Merge pull request #7 from YosysHQ/master

Syncing with official repo

28 files changed, 4101 insertions, 1029 deletions

diff --git a/frontends/aiger/Makefile.inc b/frontends/aiger/Makefile.inc
new file mode 100644
index 000000000..bc1112452
--- /dev/null
+++ b/frontends/aiger/Makefile.inc
@@ -0,0 +1,3 @@
+
+OBJS += frontends/aiger/aigerparse.o
+
diff --git a/frontends/aiger/aigerparse.cc b/frontends/aiger/aigerparse.cc
new file mode 100644
index 000000000..e8ee487e5
--- /dev/null
+++ b/frontends/aiger/aigerparse.cc
@@ -0,0 +1,1078 @@
+/*
+ *  yosys -- Yosys Open SYnthesis Suite
+ *
+ *  Copyright (C) 2012  Clifford Wolf <clifford@clifford.at>
+ *                2019  Eddie Hung <eddie@fpgeh.com>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+// [[CITE]] The AIGER And-Inverter Graph (AIG) Format Version 20071012
+// Armin Biere. The AIGER And-Inverter Graph (AIG) Format Version 20071012. Technical Report 07/1, October 2011, FMV Reports Series, Institute for Formal Models and Verification, Johannes Kepler University, Altenbergerstr. 69, 4040 Linz, Austria.
+// http://fmv.jku.at/papers/Biere-FMV-TR-07-1.pdf
+
+// https://stackoverflow.com/a/46137633
+#ifdef _MSC_VER
+#include <stdlib.h>
+#define __builtin_bswap32 _byteswap_ulong
+#elif defined(__APPLE__)
+#include <libkern/OSByteOrder.h>
+#define __builtin_bswap32 OSSwapInt32
+#endif
+#define __STDC_FORMAT_MACROS
+#include <inttypes.h>
+
+#include "kernel/yosys.h"
+#include "kernel/sigtools.h"
+#include "kernel/celltypes.h"
+#include "aigerparse.h"
+
+YOSYS_NAMESPACE_BEGIN
+
+inline int32_t from_big_endian(int32_t i32) {
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+	return __builtin_bswap32(i32);
+#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+	return i32;
+#else
+#error "Unknown endianness"
+#endif
+}
+
+#define log_debug2(...) ;
+//#define log_debug2(...) log_debug(__VA_ARGS__)
+
+struct ConstEvalAig
+{
+	RTLIL::Module *module;
+	dict<RTLIL::SigBit, RTLIL::State> values_map;
+	dict<RTLIL::SigBit, RTLIL::Cell*> sig2driver;
+	dict<SigBit, pool<RTLIL::SigBit>> sig2deps;
+
+	ConstEvalAig(RTLIL::Module *module) : module(module)
+	{
+		for (auto &it : module->cells_) {
+			if (!yosys_celltypes.cell_known(it.second->type))
+				continue;
+			for (auto &it2 : it.second->connections())
+				if (yosys_celltypes.cell_output(it.second->type, it2.first)) {
+					auto r YS_ATTRIBUTE(unused) = sig2driver.insert(std::make_pair(it2.second, it.second));
+					log_assert(r.second);
+				}
+		}
+	}
+
+	void clear()
+	{
+		values_map.clear();
+		sig2deps.clear();
+	}
+
+	void set(RTLIL::SigBit sig, RTLIL::State value)
+	{
+		auto it = values_map.find(sig);
+#ifndef NDEBUG
+		if (it != values_map.end()) {
+			RTLIL::State current_val = it->second;
+			log_assert(current_val == value);
+		}
+#endif
+		if (it != values_map.end())
+			it->second = value;
+		else
+			values_map[sig] = value;
+	}
+
+	void set_incremental(RTLIL::SigSpec sig, RTLIL::Const value)
+	{
+		log_assert(GetSize(sig) == GetSize(value));
+
+		for (int i = 0; i < GetSize(sig); i++) {
+			auto it = values_map.find(sig[i]);
+			if (it != values_map.end()) {
+				RTLIL::State current_val = it->second;
+				if (current_val != value[i])
+					for (auto dep : sig2deps[sig[i]])
+						values_map.erase(dep);
+				it->second = value[i];
+			}
+			else
+				values_map[sig[i]] = value[i];
+		}
+	}
+
+	void compute_deps(RTLIL::SigBit output, const pool<RTLIL::SigBit> &inputs)
+	{
+		sig2deps[output].insert(output);
+
+		RTLIL::Cell *cell = sig2driver.at(output);
+		RTLIL::SigBit sig_a = cell->getPort("\\A");
+		sig2deps[sig_a].reserve(sig2deps[sig_a].size() + sig2deps[output].size()); // Reserve so that any invalidation
+											   // that may occur does so here, and
+											   // not mid insertion (below)
+		sig2deps[sig_a].insert(sig2deps[output].begin(), sig2deps[output].end());
+		if (!inputs.count(sig_a))
+			compute_deps(sig_a, inputs);
+
+		if (cell->type == "$_AND_") {
+			RTLIL::SigSpec sig_b = cell->getPort("\\B");
+			sig2deps[sig_b].reserve(sig2deps[sig_b].size() + sig2deps[output].size()); // Reserve so that any invalidation
+												   // that may occur does so here, and
+												   // not mid insertion (below)
+			sig2deps[sig_b].insert(sig2deps[output].begin(), sig2deps[output].end());
+
+			if (!inputs.count(sig_b))
+				compute_deps(sig_b, inputs);
+		}
+		else if (cell->type == "$_NOT_") {
+		}
+		else log_abort();
+	}
+
+	bool eval(RTLIL::Cell *cell)
+	{
+		RTLIL::SigBit sig_y = cell->getPort("\\Y");
+		if (values_map.count(sig_y))
+			return true;
+
+		RTLIL::SigBit sig_a = cell->getPort("\\A");
+		if (!eval(sig_a))
+			return false;
+
+		RTLIL::State eval_ret = RTLIL::Sx;
+		if (cell->type == "$_NOT_") {
+			if (sig_a == State::S0) eval_ret = State::S1;
+			else if (sig_a == State::S1) eval_ret = State::S0;
+		}
+		else if (cell->type == "$_AND_") {
+			if (sig_a == State::S0) {
+				eval_ret = State::S0;
+				goto eval_end;
+			}
+
+			{
+				RTLIL::SigBit sig_b = cell->getPort("\\B");
+				if (!eval(sig_b))
+					return false;
+				if (sig_b == State::S0) {
+					eval_ret = State::S0;
+					goto eval_end;
+				}
+
+				if (sig_a != State::S1 || sig_b != State::S1)
+					goto eval_end;
+
+				eval_ret = State::S1;
+			}
+		}
+		else log_abort();
+
+eval_end:
+		set(sig_y, eval_ret);
+		return true;
+	}
+
+	bool eval(RTLIL::SigBit &sig)
+	{
+		auto it = values_map.find(sig);
+		if (it != values_map.end()) {
+			sig = it->second;
+			return true;
+		}
+
+		RTLIL::Cell *cell = sig2driver.at(sig);
+		if (!eval(cell))
+			return false;
+
+		it = values_map.find(sig);
+		if (it != values_map.end()) {
+			sig = it->second;
+			return true;
+		}
+
+		return false;
+	}
+};
+
+AigerReader::AigerReader(RTLIL::Design *design, std::istream &f, RTLIL::IdString module_name, RTLIL::IdString clk_name, std::string map_filename, bool wideports)
+	: design(design), f(f), clk_name(clk_name), map_filename(map_filename), wideports(wideports)
+{
+	module = new RTLIL::Module;
+	module->name = module_name;
+	if (design->module(module->name))
+		log_error("Duplicate definition of module %s!\n", log_id(module->name));
+}
+
+void AigerReader::parse_aiger()
+{
+	std::string header;
+	f >> header;
+	if (header != "aag" && header != "aig")
+		log_error("Unsupported AIGER file!\n");
+
+	// Parse rest of header
+	if (!(f >> M >> I >> L >> O >> A))
+		log_error("Invalid AIGER header\n");
+
+	// Optional values
+	B = C = J = F = 0;
+	if (f.peek() != ' ') goto end_of_header;
+	if (!(f >> B)) log_error("Invalid AIGER header\n");
+	if (f.peek() != ' ') goto end_of_header;
+	if (!(f >> C)) log_error("Invalid AIGER header\n");
+	if (f.peek() != ' ') goto end_of_header;
+	if (!(f >> J)) log_error("Invalid AIGER header\n");
+	if (f.peek() != ' ') goto end_of_header;
+	if (!(f >> F)) log_error("Invalid AIGER header\n");
+end_of_header:
+
+	std::string line;
+	std::getline(f, line); // Ignore up to start of next line, as standard
+	// says anything that follows could be used for
+	// optional sections
+
+	log_debug("M=%u I=%u L=%u O=%u A=%u B=%u C=%u J=%u F=%u\n", M, I, L, O, A, B, C, J, F);
+
+	line_count = 1;
+	piNum = 0;
+	flopNum = 0;
+
+	if (header == "aag")
+		parse_aiger_ascii();
+	else if (header == "aig")
+		parse_aiger_binary();
+	else
+		log_abort();
+
+	RTLIL::Wire* n0 = module->wire("\\__0__");
+	if (n0)
+		module->connect(n0, State::S0);
+
+	// Parse footer (symbol table, comments, etc.)
+	unsigned l1;
+	std::string s;
+	for (int c = f.peek(); c != EOF; c = f.peek(), ++line_count) {
+		if (c == 'i' || c == 'l' || c == 'o' || c == 'b') {
+			f.ignore(1);
+			if (!(f >> l1 >> s))
+				log_error("Line %u cannot be interpreted as a symbol entry!\n", line_count);
+
+			if ((c == 'i' && l1 > inputs.size()) || (c == 'l' && l1 > latches.size()) || (c == 'o' && l1 > outputs.size()))
+				log_error("Line %u has invalid symbol position!\n", line_count);
+
+			RTLIL::Wire* wire;
+			if (c == 'i') wire = inputs[l1];
+			else if (c == 'l') wire = latches[l1];
+			else if (c == 'o') wire = outputs[l1];
+			else if (c == 'b') wire = bad_properties[l1];
+			else log_abort();
+
+			module->rename(wire, stringf("\\%s", s.c_str()));
+		}
+		else if (c == 'j' || c == 'f') {
+			// TODO
+		}
+		else if (c == 'c') {
+			f.ignore(1);
+			if (f.peek() == '\n')
+				break;
+			// Else constraint (TODO)
+		}
+		else
+			log_error("Line %u: cannot interpret first character '%c'!\n", line_count, c);
+		std::getline(f, line); // Ignore up to start of next line
+	}
+
+	post_process();
+}
+
+static uint32_t parse_xaiger_literal(std::istream &f)
+{
+	uint32_t l;
+	f.read(reinterpret_cast<char*>(&l), sizeof(l));
+	if (f.gcount() != sizeof(l))
+#if defined(_WIN32) && defined(__MINGW32__)
+		log_error("Offset %I64d: unable to read literal!\n", static_cast<int64_t>(f.tellg()));
+#else
+		log_error("Offset %" PRId64 ": unable to read literal!\n", static_cast<int64_t>(f.tellg()));
+#endif
+	return from_big_endian(l);
+}
+
+static RTLIL::Wire* createWireIfNotExists(RTLIL::Module *module, unsigned literal)
+{
+	const unsigned variable = literal >> 1;
+	const bool invert = literal & 1;
+	RTLIL::IdString wire_name(stringf("\\__%d%s__", variable, invert ? "b" : ""));
+	RTLIL::Wire *wire = module->wire(wire_name);
+	if (wire) return wire;
+	log_debug2("Creating %s\n", wire_name.c_str());
+	wire = module->addWire(wire_name);
+	wire->port_input = wire->port_output = false;
+	if (!invert) return wire;
+	RTLIL::IdString wire_inv_name(stringf("\\__%d__", variable));
+	RTLIL::Wire *wire_inv = module->wire(wire_inv_name);
+	if (wire_inv) {
+		if (module->cell(wire_inv_name)) return wire;
+	}
+	else {
+		log_debug2("Creating %s\n", wire_inv_name.c_str());
+		wire_inv = module->addWire(wire_inv_name);
+		wire_inv->port_input = wire_inv->port_output = false;
+	}
+
+	log_debug2("Creating %s = ~%s\n", wire_name.c_str(), wire_inv_name.c_str());
+	module->addNotGate(stringf("\\__%d__$not", variable), wire_inv, wire);
+
+	return wire;
+}
+
+void AigerReader::parse_xaiger(const dict<int,IdString> &box_lookup)
+{
+	std::string header;
+	f >> header;
+	if (header != "aag" && header != "aig")
+		log_error("Unsupported AIGER file!\n");
+
+	// Parse rest of header
+	if (!(f >> M >> I >> L >> O >> A))
+		log_error("Invalid AIGER header\n");
+
+	// Optional values
+	B = C = J = F = 0;
+
+	std::string line;
+	std::getline(f, line); // Ignore up to start of next line, as standard
+	// says anything that follows could be used for
+	// optional sections
+
+	log_debug("M=%u I=%u L=%u O=%u A=%u\n", M, I, L, O, A);
+
+	line_count = 1;
+	piNum = 0;
+	flopNum = 0;
+
+	if (header == "aag")
+		parse_aiger_ascii();
+	else if (header == "aig")
+		parse_aiger_binary();
+	else
+		log_abort();
+
+	RTLIL::Wire* n0 = module->wire("\\__0__");
+	if (n0)
+		module->connect(n0, State::S0);
+
+	// Parse footer (symbol table, comments, etc.)
+	std::string s;
+	bool comment_seen = false;
+	for (int c = f.peek(); c != EOF; c = f.peek()) {
+		if (comment_seen || c == 'c') {
+			if (!comment_seen) {
+				f.ignore(1);
+				c = f.peek();
+				comment_seen = true;
+			}
+			if (c == '\n')
+				break;
+			f.ignore(1);
+			// XAIGER extensions
+			if (c == 'm') {
+				uint32_t dataSize YS_ATTRIBUTE(unused) = parse_xaiger_literal(f);
+				uint32_t lutNum = parse_xaiger_literal(f);
+				uint32_t lutSize YS_ATTRIBUTE(unused) = parse_xaiger_literal(f);
+				log_debug("m: dataSize=%u lutNum=%u lutSize=%u\n", dataSize, lutNum, lutSize);
+				ConstEvalAig ce(module);
+				for (unsigned i = 0; i < lutNum; ++i) {
+					uint32_t rootNodeID = parse_xaiger_literal(f);
+					uint32_t cutLeavesM = parse_xaiger_literal(f);
+					log_debug2("rootNodeID=%d cutLeavesM=%d\n", rootNodeID, cutLeavesM);
+					RTLIL::Wire *output_sig = module->wire(stringf("\\__%d__", rootNodeID));
+					uint32_t nodeID;
+					RTLIL::SigSpec input_sig;
+					for (unsigned j = 0; j < cutLeavesM; ++j) {
+						nodeID = parse_xaiger_literal(f);
+						log_debug2("\t%u\n", nodeID);
+						RTLIL::Wire *wire = module->wire(stringf("\\__%d__", nodeID));
+						log_assert(wire);
+						input_sig.append(wire);
+					}
+					// TODO: Compute LUT mask from AIG in less than O(2 ** input_sig.size())
+					ce.clear();
+					ce.compute_deps(output_sig, input_sig.to_sigbit_pool());
+					RTLIL::Const lut_mask(RTLIL::State::Sx, 1 << input_sig.size());
+					for (int j = 0; j < (1 << cutLeavesM); ++j) {
+						int gray = j ^ (j >> 1);
+						ce.set_incremental(input_sig, RTLIL::Const{gray, static_cast<int>(cutLeavesM)});
+						RTLIL::SigBit o(output_sig);
+						bool success YS_ATTRIBUTE(unused) = ce.eval(o);
+						log_assert(success);
+						log_assert(o.wire == nullptr);
+						lut_mask[gray] = o.data;
+					}
+					RTLIL::Cell *output_cell = module->cell(stringf("\\__%d__$and", rootNodeID));
+					log_assert(output_cell);
+					module->remove(output_cell);
+					module->addLut(stringf("\\__%d__$lut", rootNodeID), input_sig, output_sig, std::move(lut_mask));
+				}
+			}
+			else if (c == 'r') {
+				uint32_t dataSize YS_ATTRIBUTE(unused) = parse_xaiger_literal(f);
+				flopNum = parse_xaiger_literal(f);
+				log_debug("flopNum: %u\n", flopNum);
+				log_assert(dataSize == (flopNum+1) * sizeof(uint32_t));
+				f.ignore(flopNum * sizeof(uint32_t));
+			}
+			else if (c == 'n') {
+				parse_xaiger_literal(f);
+				f >> s;
+				log_debug("n: '%s'\n", s.c_str());
+			}
+			else if (c == 'h') {
+				f.ignore(sizeof(uint32_t));
+				uint32_t version YS_ATTRIBUTE(unused) = parse_xaiger_literal(f);
+				log_assert(version == 1);
+				uint32_t ciNum YS_ATTRIBUTE(unused) = parse_xaiger_literal(f);
+				log_debug("ciNum = %u\n", ciNum);
+				uint32_t coNum YS_ATTRIBUTE(unused) = parse_xaiger_literal(f);
+				log_debug("coNum = %u\n", coNum);
+				piNum = parse_xaiger_literal(f);
+				log_debug("piNum = %u\n", piNum);
+				uint32_t poNum YS_ATTRIBUTE(unused) = parse_xaiger_literal(f);
+				log_debug("poNum = %u\n", poNum);
+				uint32_t boxNum = parse_xaiger_literal(f);
+				log_debug("boxNum = %u\n", boxNum);
+				for (unsigned i = 0; i < boxNum; i++) {
+					f.ignore(2*sizeof(uint32_t));
+					uint32_t boxUniqueId = parse_xaiger_literal(f);
+					log_assert(boxUniqueId > 0);
+					uint32_t oldBoxNum = parse_xaiger_literal(f);
+					RTLIL::Cell* cell = module->addCell(stringf("$__box%u__", oldBoxNum), box_lookup.at(boxUniqueId));
+					boxes.emplace_back(cell);
+				}
+			}
+			else if (c == 'a' || c == 'i' || c == 'o') {
+				uint32_t dataSize = parse_xaiger_literal(f);
+				f.ignore(dataSize);
+			}
+			else {
+				break;
+			}
+		}
+		else
+			log_error("Line %u: cannot interpret first character '%c'!\n", line_count, c);
+	}
+
+	post_process();
+}
+
+void AigerReader::parse_aiger_ascii()
+{
+	std::string line;
+	std::stringstream ss;
+
+	unsigned l1, l2, l3;
+
+	// Parse inputs
+	for (unsigned i = 1; i <= I; ++i, ++line_count) {
+		if (!(f >> l1))
+			log_error("Line %u cannot be interpreted as an input!\n", line_count);
+		log_debug2("%d is an input\n", l1);
+		log_assert(!(l1 & 1)); // Inputs can't be inverted
+		RTLIL::Wire *wire = createWireIfNotExists(module, l1);
+		wire->port_input = true;
+		inputs.push_back(wire);
+	}
+
+	// Parse latches
+	RTLIL::Wire *clk_wire = nullptr;
+	if (L > 0 && !clk_name.empty()) {
+		clk_wire = module->wire(clk_name);
+		log_assert(!clk_wire);
+		log_debug2("Creating %s\n", clk_name.c_str());
+		clk_wire = module->addWire(clk_name);
+		clk_wire->port_input = true;
+		clk_wire->port_output = false;
+	}
+	for (unsigned i = 0; i < L; ++i, ++line_count) {
+		if (!(f >> l1 >> l2))
+			log_error("Line %u cannot be interpreted as a latch!\n", line_count);
+		log_debug2("%d %d is a latch\n", l1, l2);
+		log_assert(!(l1 & 1));
+		RTLIL::Wire *q_wire = createWireIfNotExists(module, l1);
+		RTLIL::Wire *d_wire = createWireIfNotExists(module, l2);
+
+		if (clk_wire)
+			module->addDffGate(NEW_ID, clk_wire, d_wire, q_wire);
+		else
+			module->addFfGate(NEW_ID, d_wire, q_wire);
+
+		// Reset logic is optional in AIGER 1.9
+		if (f.peek() == ' ') {
+			if (!(f >> l3))
+				log_error("Line %u cannot be interpreted as a latch!\n", line_count);
+
+			if (l3 == 0)
+				q_wire->attributes["\\init"] = State::S0;
+			else if (l3 == 1)
+				q_wire->attributes["\\init"] = State::S1;
+			else if (l3 == l1) {
+				//q_wire->attributes["\\init"] = RTLIL::Sx;
+			}
+			else
+				log_error("Line %u has invalid reset literal for latch!\n", line_count);
+		}
+		else {
+			// AIGER latches are assumed to be initialized to zero
+			q_wire->attributes["\\init"] = State::S0;
+		}
+		latches.push_back(q_wire);
+	}
+
+	// Parse outputs
+	for (unsigned i = 0; i < O; ++i, ++line_count) {
+		if (!(f >> l1))
+			log_error("Line %u cannot be interpreted as an output!\n", line_count);
+
+		log_debug2("%d is an output\n", l1);
+		const unsigned variable = l1 >> 1;
+		const bool invert = l1 & 1;
+		RTLIL::IdString wire_name(stringf("\\__%d%s__", variable, invert ? "b" : "")); // FIXME: is "b" the right suffix?
+		RTLIL::Wire *wire = module->wire(wire_name);
+		if (!wire)
+			wire = createWireIfNotExists(module, l1);
+		else if (wire->port_input || wire->port_output) {
+			RTLIL::Wire *new_wire = module->addWire(NEW_ID);
+			module->connect(new_wire, wire);
+			wire = new_wire;
+		}
+		wire->port_output = true;
+		outputs.push_back(wire);
+	}
+
+	// Parse bad properties
+	for (unsigned i = 0; i < B; ++i, ++line_count) {
+		if (!(f >> l1))
+			log_error("Line %u cannot be interpreted as a bad state property!\n", line_count);
+
+		log_debug2("%d is a bad state property\n", l1);
+		RTLIL::Wire *wire = createWireIfNotExists(module, l1);
+		wire->port_output = true;
+		bad_properties.push_back(wire);
+	}
+
+	// TODO: Parse invariant constraints
+	for (unsigned i = 0; i < C; ++i, ++line_count)
+		std::getline(f, line); // Ignore up to start of next line
+
+	// TODO: Parse justice properties
+	for (unsigned i = 0; i < J; ++i, ++line_count)
+		std::getline(f, line); // Ignore up to start of next line
+
+	// TODO: Parse fairness constraints
+	for (unsigned i = 0; i < F; ++i, ++line_count)
+		std::getline(f, line); // Ignore up to start of next line
+
+	// Parse AND
+	for (unsigned i = 0; i < A; ++i) {
+		if (!(f >> l1 >> l2 >> l3))
+			log_error("Line %u cannot be interpreted as an AND!\n", line_count);
+
+		log_debug2("%d %d %d is an AND\n", l1, l2, l3);
+		log_assert(!(l1 & 1));
+		RTLIL::Wire *o_wire = createWireIfNotExists(module, l1);
+		RTLIL::Wire *i1_wire = createWireIfNotExists(module, l2);
+		RTLIL::Wire *i2_wire = createWireIfNotExists(module, l3);
+		module->addAndGate(o_wire->name.str() + "$and", i1_wire, i2_wire, o_wire);
+	}
+	std::getline(f, line); // Ignore up to start of next line
+}
+
+static unsigned parse_next_delta_literal(std::istream &f, unsigned ref)
+{
+	unsigned x = 0, i = 0;
+	unsigned char ch;
+	while ((ch = f.get()) & 0x80)
+		x |= (ch & 0x7f) << (7 * i++);
+	return ref - (x | (ch << (7 * i)));
+}
+
+void AigerReader::parse_aiger_binary()
+{
+	unsigned l1, l2, l3;
+	std::string line;
+
+	// Parse inputs
+	for (unsigned i = 1; i <= I; ++i) {
+		log_debug2("%d is an input\n", i);
+		RTLIL::Wire *wire = createWireIfNotExists(module, i << 1);
+		wire->port_input = true;
+		log_assert(!wire->port_output);
+		inputs.push_back(wire);
+	}
+
+	// Parse latches
+	RTLIL::Wire *clk_wire = nullptr;
+	if (L > 0 && !clk_name.empty()) {
+		clk_wire = module->wire(clk_name);
+		log_assert(!clk_wire);
+		log_debug2("Creating %s\n", clk_name.c_str());
+		clk_wire = module->addWire(clk_name);
+		clk_wire->port_input = true;
+		clk_wire->port_output = false;
+	}
+	l1 = (I+1) * 2;
+	for (unsigned i = 0; i < L; ++i, ++line_count, l1 += 2) {
+		if (!(f >> l2))
+			log_error("Line %u cannot be interpreted as a latch!\n", line_count);
+		log_debug("%d %d is a latch\n", l1, l2);
+		RTLIL::Wire *q_wire = createWireIfNotExists(module, l1);
+		RTLIL::Wire *d_wire = createWireIfNotExists(module, l2);
+
+		if (clk_wire)
+			module->addDff(NEW_ID, clk_wire, d_wire, q_wire);
+		else
+			module->addFf(NEW_ID, d_wire, q_wire);
+
+		// Reset logic is optional in AIGER 1.9
+		if (f.peek() == ' ') {
+			if (!(f >> l3))
+				log_error("Line %u cannot be interpreted as a latch!\n", line_count);
+
+			if (l3 == 0)
+				q_wire->attributes["\\init"] = State::S0;
+			else if (l3 == 1)
+				q_wire->attributes["\\init"] = State::S1;
+			else if (l3 == l1) {
+				//q_wire->attributes["\\init"] = RTLIL::Sx;
+			}
+			else
+				log_error("Line %u has invalid reset literal for latch!\n", line_count);
+		}
+		else {
+			// AIGER latches are assumed to be initialized to zero
+			q_wire->attributes["\\init"] = State::S0;
+		}
+		latches.push_back(q_wire);
+	}
+
+	// Parse outputs
+	for (unsigned i = 0; i < O; ++i, ++line_count) {
+		if (!(f >> l1))
+			log_error("Line %u cannot be interpreted as an output!\n", line_count);
+
+		log_debug2("%d is an output\n", l1);
+		const unsigned variable = l1 >> 1;
+		const bool invert = l1 & 1;
+		RTLIL::IdString wire_name(stringf("\\__%d%s__", variable, invert ? "b" : "")); // FIXME: is "_b" the right suffix?
+		RTLIL::Wire *wire = module->wire(wire_name);
+		if (!wire)
+			wire = createWireIfNotExists(module, l1);
+		else if (wire->port_input || wire->port_output) {
+			RTLIL::Wire *new_wire = module->addWire(NEW_ID);
+			module->connect(new_wire, wire);
+			wire = new_wire;
+		}
+		wire->port_output = true;
+		outputs.push_back(wire);
+	}
+	std::getline(f, line); // Ignore up to start of next line
+
+	// Parse bad properties
+	for (unsigned i = 0; i < B; ++i, ++line_count) {
+		if (!(f >> l1))
+			log_error("Line %u cannot be interpreted as a bad state property!\n", line_count);
+
+		log_debug2("%d is a bad state property\n", l1);
+		RTLIL::Wire *wire = createWireIfNotExists(module, l1);
+		wire->port_output = true;
+		bad_properties.push_back(wire);
+	}
+	if (B > 0)
+		std::getline(f, line); // Ignore up to start of next line
+
+	// TODO: Parse invariant constraints
+	for (unsigned i = 0; i < C; ++i, ++line_count)
+		std::getline(f, line); // Ignore up to start of next line
+
+	// TODO: Parse justice properties
+	for (unsigned i = 0; i < J; ++i, ++line_count)
+		std::getline(f, line); // Ignore up to start of next line
+
+	// TODO: Parse fairness constraints
+	for (unsigned i = 0; i < F; ++i, ++line_count)
+		std::getline(f, line); // Ignore up to start of next line
+
+	// Parse AND
+	l1 = (I+L+1) << 1;
+	for (unsigned i = 0; i < A; ++i, ++line_count, l1 += 2) {
+		l2 = parse_next_delta_literal(f, l1);
+		l3 = parse_next_delta_literal(f, l2);
+
+		log_debug2("%d %d %d is an AND\n", l1, l2, l3);
+		log_assert(!(l1 & 1));
+		RTLIL::Wire *o_wire = createWireIfNotExists(module, l1);
+		RTLIL::Wire *i1_wire = createWireIfNotExists(module, l2);
+		RTLIL::Wire *i2_wire = createWireIfNotExists(module, l3);
+		module->addAndGate(o_wire->name.str() + "$and", i1_wire, i2_wire, o_wire);
+	}
+}
+
+void AigerReader::post_process()
+{
+	pool<IdString> seen_boxes;
+	unsigned ci_count = 0, co_count = 0;
+	for (auto cell : boxes) {
+		RTLIL::Module* box_module = design->module(cell->type);
+		log_assert(box_module);
+
+		if (seen_boxes.insert(cell->type).second) {
+			auto it = box_module->attributes.find("\\abc_carry");
+			if (it != box_module->attributes.end()) {
+				RTLIL::Wire *carry_in = nullptr, *carry_out = nullptr;
+				auto carry_in_out = it->second.decode_string();
+				auto pos = carry_in_out.find(',');
+				if (pos == std::string::npos)
+					log_error("'abc_carry' attribute on module '%s' does not contain ','.\n", log_id(cell->type));
+				auto carry_in_name = RTLIL::escape_id(carry_in_out.substr(0, pos));
+				carry_in = box_module->wire(carry_in_name);
+				if (!carry_in || !carry_in->port_input)
+					log_error("'abc_carry' on module '%s' contains '%s' which does not exist or is not an input port.\n", log_id(cell->type), carry_in_name.c_str());
+
+				auto carry_out_name = RTLIL::escape_id(carry_in_out.substr(pos+1));
+				carry_out = box_module->wire(carry_out_name);
+				if (!carry_out || !carry_out->port_output)
+					log_error("'abc_carry' on module '%s' contains '%s' which does not exist or is not an output port.\n", log_id(cell->type), carry_out_name.c_str());
+
+				auto &ports = box_module->ports;
+				for (auto jt = ports.begin(); jt != ports.end(); ) {
+					RTLIL::Wire* w = box_module->wire(*jt);
+					log_assert(w);
+					if (w == carry_in || w == carry_out) {
+						jt = ports.erase(jt);
+						continue;
+					}
+					if (w->port_id > carry_in->port_id)
+						--w->port_id;
+					if (w->port_id > carry_out->port_id)
+						--w->port_id;
+					log_assert(w->port_input || w->port_output);
+					log_assert(ports[w->port_id-1] == w->name);
+					++jt;
+				}
+				ports.push_back(carry_in->name);
+				carry_in->port_id = ports.size();
+				ports.push_back(carry_out->name);
+				carry_out->port_id = ports.size();
+			}
+		}
+
+		// NB: Assume box_module->ports are sorted alphabetically
+		//     (as RTLIL::Module::fixup_ports() would do)
+		for (auto port_name : box_module->ports) {
+			RTLIL::Wire* port = box_module->wire(port_name);
+			log_assert(port);
+			RTLIL::SigSpec rhs;
+			for (int i = 0; i < GetSize(port); i++) {
+				RTLIL::Wire* wire = nullptr;
+				if (port->port_input) {
+					log_assert(co_count < outputs.size());
+					wire = outputs[co_count++];
+					log_assert(wire);
+					log_assert(wire->port_output);
+					wire->port_output = false;
+				}
+				if (port->port_output) {
+					log_assert((piNum + ci_count) < inputs.size());
+					wire = inputs[piNum + ci_count++];
+					log_assert(wire);
+					log_assert(wire->port_input);
+					wire->port_input = false;
+				}
+				rhs.append(wire);
+			}
+
+			cell->setPort(port_name, rhs);
+		}
+	}
+
+	dict<RTLIL::IdString, int> wideports_cache;
+
+	if (!map_filename.empty()) {
+		std::ifstream mf(map_filename);
+		std::string type, symbol;
+		int variable, index;
+		while (mf >> type >> variable >> index >> symbol) {
+			RTLIL::IdString escaped_s = RTLIL::escape_id(symbol);
+			if (type == "input") {
+				log_assert(static_cast<unsigned>(variable) < inputs.size());
+				RTLIL::Wire* wire = inputs[variable];
+				log_assert(wire);
+				log_assert(wire->port_input);
+				log_debug("Renaming input %s", log_id(wire));
+
+				if (index == 0) {
+					// Cope with the fact that a CI might be identical
+					// to a PI (necessary due to ABC); in those cases
+					// simply connect the latter to the former
+					RTLIL::Wire* existing = module->wire(escaped_s);
+					if (!existing)
+						module->rename(wire, escaped_s);
+					else {
+						wire->port_input = false;
+						module->connect(wire, existing);
+					}
+				}
+				else if (index > 0) {
+					std::string indexed_name = stringf("%s[%d]", escaped_s.c_str(), index);
+					RTLIL::Wire* existing = module->wire(indexed_name);
+					if (!existing) {
+						module->rename(wire, indexed_name);
+						if (wideports)
+							wideports_cache[escaped_s] = std::max(wideports_cache[escaped_s], index);
+					}
+					else {
+						module->connect(wire, existing);
+						wire->port_input = false;
+					}
+				}
+				log_debug(" -> %s\n", log_id(wire));
+			}
+			else if (type == "output") {
+				log_assert(static_cast<unsigned>(variable + co_count) < outputs.size());
+				RTLIL::Wire* wire = outputs[variable + co_count];
+				log_assert(wire);
+				log_assert(wire->port_output);
+				if (escaped_s == "$__dummy__") {
+					wire->port_output = false;
+					continue;
+				}
+				log_debug("Renaming output %s", log_id(wire));
+
+				if (index == 0) {
+					// Cope with the fact that a CO might be identical
+					// to a PO (necessary due to ABC); in those cases
+					// simply connect the latter to the former
+					RTLIL::Wire* existing = module->wire(escaped_s);
+					if (!existing) {
+						if (escaped_s.ends_with("$inout.out")) {
+							wire->port_output = false;
+							RTLIL::Wire *in_wire = module->wire(escaped_s.substr(0, escaped_s.size()-10));
+							log_assert(in_wire);
+							log_assert(in_wire->port_input && !in_wire->port_output);
+							in_wire->port_output = true;
+							module->connect(in_wire, wire);
+						}
+						else
+							module->rename(wire, escaped_s);
+					}
+					else {
+						wire->port_output = false;
+						module->connect(wire, existing);
+						wire = existing;
+					}
+				}
+				else if (index > 0) {
+					std::string indexed_name = stringf("%s[%d]", escaped_s.c_str(), index);
+					RTLIL::Wire* existing = module->wire(indexed_name);
+					if (!existing) {
+						if (escaped_s.ends_with("$inout.out")) {
+							wire->port_output = false;
+							RTLIL::Wire *in_wire = module->wire(stringf("%s[%d]", escaped_s.substr(0, escaped_s.size()-10).c_str(), index));
+							log_assert(in_wire);
+							log_assert(in_wire->port_input && !in_wire->port_output);
+							in_wire->port_output = true;
+							module->connect(in_wire, wire);
+						}
+						else {
+							module->rename(wire, indexed_name);
+							if (wideports)
+								wideports_cache[escaped_s] = std::max(wideports_cache[escaped_s], index);
+						}
+					}
+					else {
+						module->connect(wire, existing);
+						wire->port_output = false;
+					}
+				}
+				log_debug(" -> %s\n", log_id(wire));
+			}
+			else if (type == "box") {
+				RTLIL::Cell* cell = module->cell(stringf("$__box%d__", variable));
+				if (cell) { // ABC could have optimised this box away
+					module->rename(cell, escaped_s);
+					for (const auto &i : cell->connections()) {
+						RTLIL::IdString port_name = i.first;
+						RTLIL::SigSpec rhs = i.second;
+						int index = 0;
+						for (auto bit : rhs.bits()) {
+							RTLIL::Wire* wire = bit.wire;
+							RTLIL::IdString escaped_s = RTLIL::escape_id(stringf("%s.%s", log_id(cell), log_id(port_name)));
+							if (index == 0)
+								module->rename(wire, escaped_s);
+							else if (index > 0) {
+								module->rename(wire, stringf("%s[%d]", escaped_s.c_str(), index));
+								if (wideports)
+									wideports_cache[escaped_s] = std::max(wideports_cache[escaped_s], index);
+							}
+							index++;
+						}
+					}
+				}
+			}
+			else
+				log_error("Symbol type '%s' not recognised.\n", type.c_str());
+		}
+	}
+
+	for (auto &wp : wideports_cache) {
+		auto name = wp.first;
+		int width = wp.second + 1;
+
+		RTLIL::Wire *wire = module->wire(name);
+		if (wire)
+			module->rename(wire, RTLIL::escape_id(stringf("%s[%d]", name.c_str(), 0)));
+
+		// Do not make ports with a mix of input/output into
+		// wide ports
+		bool port_input = false, port_output = false;
+		for (int i = 0; i < width; i++) {
+			RTLIL::IdString other_name = name.str() + stringf("[%d]", i);
+			RTLIL::Wire *other_wire = module->wire(other_name);
+			if (other_wire) {
+				port_input = port_input || other_wire->port_input;
+				port_output = port_output || other_wire->port_output;
+			}
+		}
+
+		wire = module->addWire(name, width);
+		wire->port_input = port_input;
+		wire->port_output = port_output;
+
+		for (int i = 0; i < width; i++) {
+			RTLIL::IdString other_name = name.str() + stringf("[%d]", i);
+			RTLIL::Wire *other_wire = module->wire(other_name);
+			if (other_wire) {
+				other_wire->port_input = false;
+				other_wire->port_output = false;
+			}
+			if (wire->port_input) {
+				if (other_wire)
+					module->connect(other_wire, SigSpec(wire, i));
+			}
+			else {
+								  // Since we skip POs that are connected to Sx,
+								  // re-connect them here
+				module->connect(SigSpec(wire, i), other_wire ? other_wire : SigSpec(RTLIL::Sx));
+			}
+		}
+	}
+
+	module->fixup_ports();
+
+	// Insert into a new (temporary) design so that "clean" will only
+	// operate (and run checks on) this one module
+	RTLIL::Design *mapped_design = new RTLIL::Design;
+	mapped_design->add(module);
+	Pass::call(mapped_design, "clean");
+	mapped_design->modules_.erase(module->name);
+	delete mapped_design;
+
+	design->add(module);
+
+	for (auto cell : module->cells().to_vector()) {
+		if (cell->type != "$lut") continue;
+		auto y_port = cell->getPort("\\Y").as_bit();
+		if (y_port.wire->width == 1)
+			module->rename(cell, stringf("%s$lut", y_port.wire->name.c_str()));
+		else
+			module->rename(cell, stringf("%s[%d]$lut", y_port.wire->name.c_str(), y_port.offset));
+	}
+}
+
+struct AigerFrontend : public Frontend {
+	AigerFrontend() : Frontend("aiger", "read AIGER file") { }
+	void help() YS_OVERRIDE
+	{
+		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
+		log("\n");
+		log("    read_aiger [options] [filename]\n");
+		log("\n");
+		log("Load module from an AIGER file into the current design.\n");
+		log("\n");
+		log("    -module_name <module_name>\n");
+		log("        Name of module to be created (default: <filename>)\n");
+		log("\n");
+		log("    -clk_name <wire_name>\n");
+		log("        If specified, AIGER latches to be transformed into $_DFF_P_ cells\n");
+		log("        clocked by wire of this name. Otherwise, $_FF_ cells will be used.\n");
+		log("\n");
+		log("    -map <filename>\n");
+		log("        read file with port and latch symbols\n");
+		log("\n");
+		log("    -wideports\n");
+		log("        Merge ports that match the pattern 'name[int]' into a single\n");
+		log("        multi-bit port 'name'.\n");
+		log("\n");
+	}
+	void execute(std::istream *&f, std::string filename, std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
+	{
+		log_header(design, "Executing AIGER frontend.\n");
+
+		RTLIL::IdString clk_name = "\\clk";
+		RTLIL::IdString module_name;
+		std::string map_filename;
+		bool wideports = false;
+
+		size_t argidx;
+		for (argidx = 1; argidx < args.size(); argidx++) {
+			std::string arg = args[argidx];
+			if (arg == "-module_name" && argidx+1 < args.size()) {
+				module_name = RTLIL::escape_id(args[++argidx]);
+				continue;
+			}
+			if (arg == "-clk_name" && argidx+1 < args.size()) {
+				clk_name = RTLIL::escape_id(args[++argidx]);
+				continue;
+			}
+			if (map_filename.empty() && arg == "-map" && argidx+1 < args.size()) {
+				map_filename = args[++argidx];
+				continue;
+			}
+			if (arg == "-wideports") {
+				wideports = true;
+				continue;
+			}
+			break;
+		}
+		extra_args(f, filename, args, argidx);
+
+		if (module_name.empty()) {
+#ifdef _WIN32
+			char fname[_MAX_FNAME];
+			_splitpath(filename.c_str(), NULL /* drive */, NULL /* dir */, fname, NULL /* ext */);
+			module_name = fname;
+#else
+			char* bn = strdup(filename.c_str());
+			module_name = RTLIL::escape_id(bn);
+			free(bn);
+#endif
+		}
+
+		AigerReader reader(design, *f, module_name, clk_name, map_filename, wideports);
+		reader.parse_aiger();
+	}
+} AigerFrontend;
+
+YOSYS_NAMESPACE_END
diff --git a/frontends/aiger/aigerparse.h b/frontends/aiger/aigerparse.h
new file mode 100644
index 000000000..583c9d0f9
--- /dev/null
+++ b/frontends/aiger/aigerparse.h
@@ -0,0 +1,58 @@
+/*
+ *  yosys -- Yosys Open SYnthesis Suite
+ *
+ *  Copyright (C) 2012  Clifford Wolf <clifford@clifford.at>
+ *                2019  Eddie Hung <eddie@fpgeh.com>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#ifndef ABC_AIGERPARSE
+#define ABC_AIGERPARSE
+
+#include "kernel/yosys.h"
+
+YOSYS_NAMESPACE_BEGIN
+
+struct AigerReader
+{
+    RTLIL::Design *design;
+    std::istream &f;
+    RTLIL::IdString clk_name;
+    RTLIL::Module *module;
+    std::string map_filename;
+    bool wideports;
+
+    unsigned M, I, L, O, A;
+    unsigned B, C, J, F; // Optional in AIGER 1.9
+    unsigned line_count;
+    uint32_t piNum, flopNum;
+
+    std::vector<RTLIL::Wire*> inputs;
+    std::vector<RTLIL::Wire*> latches;
+    std::vector<RTLIL::Wire*> outputs;
+    std::vector<RTLIL::Wire*> bad_properties;
+    std::vector<RTLIL::Cell*> boxes;
+
+    AigerReader(RTLIL::Design *design, std::istream &f, RTLIL::IdString module_name, RTLIL::IdString clk_name, std::string map_filename, bool wideports);
+    void parse_aiger();
+    void parse_xaiger(const dict<int,IdString> &box_lookup);
+    void parse_aiger_ascii();
+    void parse_aiger_binary();
+    void post_process();
+};
+
+YOSYS_NAMESPACE_END
+
+#endif
diff --git a/frontends/ast/ast.cc b/frontends/ast/ast.cc
index 999202b47..21279cbfa 100644
--- a/frontends/ast/ast.cc
+++ b/frontends/ast/ast.cc
@@ -2,6 +2,7 @@
  *  yosys -- Yosys Open SYnthesis Suite
  *
  *  Copyright (C) 2012  Clifford Wolf <clifford@clifford.at>
+ *  Copyright (C) 2018  Ruben Undheim <ruben.undheim@gmail.com>
  *
  *  Permission to use, copy, modify, and/or distribute this software for any
  *  purpose with or without fee is hereby granted, provided that the above
@@ -35,17 +36,17 @@ YOSYS_NAMESPACE_BEGIN
 using namespace AST;
 using namespace AST_INTERNAL;
 
-// instanciate global variables (public API)
+// instantiate global variables (public API)
 namespace AST {
 	std::string current_filename;
 	void (*set_line_num)(int) = NULL;
 	int (*get_line_num)() = NULL;
 }
 
-// instanciate global variables (private API)
+// instantiate global variables (private API)
 namespace AST_INTERNAL {
-	bool flag_dump_ast1, flag_dump_ast2, flag_dump_vlog, flag_dump_rtlil, flag_nolatches, flag_nomeminit;
-	bool flag_nomem2reg, flag_mem2reg, flag_lib, flag_noopt, flag_icells, flag_autowire;
+	bool flag_dump_ast1, flag_dump_ast2, flag_no_dump_ptr, flag_dump_vlog1, flag_dump_vlog2, flag_dump_rtlil, flag_nolatches, flag_nomeminit;
+	bool flag_nomem2reg, flag_mem2reg, flag_noblackbox, flag_lib, flag_nowb, flag_noopt, flag_icells, flag_pwires, flag_autowire;
 	AstNode *current_ast, *current_ast_mod;
 	std::map<std::string, AstNode*> current_scope;
 	const dict<RTLIL::SigBit, RTLIL::SigBit> *genRTLIL_subst_ptr = NULL;
@@ -153,9 +154,15 @@ std::string AST::type2str(AstNodeType type)
 	X(AST_GENIF)
 	X(AST_GENCASE)
 	X(AST_GENBLOCK)
+	X(AST_TECALL)
 	X(AST_POSEDGE)
 	X(AST_NEGEDGE)
 	X(AST_EDGE)
+	X(AST_INTERFACE)
+	X(AST_INTERFACEPORT)
+	X(AST_INTERFACEPORTTYPE)
+	X(AST_MODPORT)
+	X(AST_MODPORTMEMBER)
 	X(AST_PACKAGE)
 #undef X
 	default:
@@ -171,8 +178,7 @@ bool AstNode::get_bool_attribute(RTLIL::IdString id)
 
 	AstNode *attr = attributes.at(id);
 	if (attr->type != AST_CONSTANT)
-		log_error("Attribute `%s' with non-constant value at %s:%d!\n",
-				id.c_str(), attr->filename.c_str(), attr->linenum);
+		log_file_error(attr->filename, attr->linenum, "Attribute `%s' with non-constant value!\n", id.c_str());
 
 	return attr->integer != 0;
 }
@@ -191,8 +197,13 @@ AstNode::AstNode(AstNodeType type, AstNode *child1, AstNode *child2, AstNode *ch
 	is_input = false;
 	is_output = false;
 	is_reg = false;
+	is_logic = false;
 	is_signed = false;
 	is_string = false;
+	is_wand = false;
+	is_wor = false;
+	is_unsized = false;
+	was_checked = false;
 	range_valid = false;
 	range_swapped = false;
 	port_id = 0;
@@ -265,18 +276,20 @@ void AstNode::dumpAst(FILE *f, std::string indent) const
 	std::string type_name = type2str(type);
 	fprintf(f, "%s%s <%s:%d>", indent.c_str(), type_name.c_str(), filename.c_str(), linenum);
 
-	if (id2ast)
-		fprintf(f, " [%p -> %p]", this, id2ast);
-	else
-		fprintf(f, " [%p]", this);
+	if (!flag_no_dump_ptr) {
+		if (id2ast)
+			fprintf(f, " [%p -> %p]", this, id2ast);
+		else
+			fprintf(f, " [%p]", this);
+	}
 
 	if (!str.empty())
 		fprintf(f, " str='%s'", str.c_str());
 	if (!bits.empty()) {
 		fprintf(f, " bits='");
 		for (size_t i = bits.size(); i > 0; i--)
-			fprintf(f, "%c", bits[i-1] == RTLIL::S0 ? '0' :
-					bits[i-1] == RTLIL::S1 ? '1' :
+			fprintf(f, "%c", bits[i-1] == State::S0 ? '0' :
+					bits[i-1] == State::S1 ? '1' :
 					bits[i-1] == RTLIL::Sx ? 'x' :
 					bits[i-1] == RTLIL::Sz ? 'z' : '?');
 		fprintf(f, "'(%d)", GetSize(bits));
@@ -285,7 +298,9 @@ void AstNode::dumpAst(FILE *f, std::string indent) const
 		fprintf(f, " input");
 	if (is_output)
 		fprintf(f, " output");
-	if (is_reg)
+	if (is_logic)
+		fprintf(f, " logic");
+	if (is_reg) // this is an AST dump, not Verilog - if we see "logic reg" that's fine.
 		fprintf(f, " reg");
 	if (is_signed)
 		fprintf(f, " signed");
@@ -425,9 +440,12 @@ void AstNode::dumpVlog(FILE *f, std::string indent) const
 		break;
 
 	case AST_RANGE:
-		if (range_valid)
-			fprintf(f, "[%d:%d]", range_left, range_right);
-		else {
+		if (range_valid) {
+			if (range_swapped)
+				fprintf(f, "[%d:%d]", range_right, range_left);
+			else
+				fprintf(f, "[%d:%d]", range_left, range_right);
+		} else {
 			for (auto child : children) {
 				fprintf(f, "%c", first ? '[' : ':');
 				child->dumpVlog(f, "");
@@ -556,7 +574,8 @@ void AstNode::dumpVlog(FILE *f, std::string indent) const
 
 	case AST_CONCAT:
 		fprintf(f, "{");
-		for (auto child : children) {
+		for (int i = GetSize(children)-1; i >= 0; i--) {
+			auto child = children[i];
 			if (!first)
 				fprintf(f, ", ");
 			child->dumpVlog(f, "");
@@ -652,6 +671,8 @@ bool AstNode::operator==(const AstNode &other) const
 		return false;
 	if (is_output != other.is_output)
 		return false;
+	if (is_logic != other.is_logic)
+		return false;
 	if (is_reg != other.is_reg)
 		return false;
 	if (is_signed != other.is_signed)
@@ -700,7 +721,7 @@ AstNode *AstNode::mkconst_int(uint32_t v, bool is_signed, int width)
 	node->integer = v;
 	node->is_signed = is_signed;
 	for (int i = 0; i < width; i++) {
-		node->bits.push_back((v & 1) ? RTLIL::S1 : RTLIL::S0);
+		node->bits.push_back((v & 1) ? State::S1 : State::S0);
 		v = v >> 1;
 	}
 	node->range_valid = true;
@@ -710,23 +731,29 @@ AstNode *AstNode::mkconst_int(uint32_t v, bool is_signed, int width)
 }
 
 // create an AST node for a constant (using a bit vector as value)
-AstNode *AstNode::mkconst_bits(const std::vector<RTLIL::State> &v, bool is_signed)
+AstNode *AstNode::mkconst_bits(const std::vector<RTLIL::State> &v, bool is_signed, bool is_unsized)
 {
 	AstNode *node = new AstNode(AST_CONSTANT);
 	node->is_signed = is_signed;
 	node->bits = v;
 	for (size_t i = 0; i < 32; i++) {
 		if (i < node->bits.size())
-			node->integer |= (node->bits[i] == RTLIL::S1) << i;
+			node->integer |= (node->bits[i] == State::S1) << i;
 		else if (is_signed && !node->bits.empty())
-			node->integer |= (node->bits.back() == RTLIL::S1) << i;
+			node->integer |= (node->bits.back() == State::S1) << i;
 	}
 	node->range_valid = true;
 	node->range_left = node->bits.size()-1;
 	node->range_right = 0;
+	node->is_unsized = is_unsized;
 	return node;
 }
 
+AstNode *AstNode::mkconst_bits(const std::vector<RTLIL::State> &v, bool is_signed)
+{
+	return mkconst_bits(v, is_signed, false);
+}
+
 // create an AST node for a constant (using a string in bit vector form as value)
 AstNode *AstNode::mkconst_str(const std::vector<RTLIL::State> &v)
 {
@@ -745,7 +772,7 @@ AstNode *AstNode::mkconst_str(const std::string &str)
 	for (size_t i = 0; i < str.size(); i++) {
 		unsigned char ch = str[str.size() - i - 1];
 		for (int j = 0; j < 8; j++) {
-			data.push_back((ch & 1) ? RTLIL::S1 : RTLIL::S0);
+			data.push_back((ch & 1) ? State::S1 : State::S0);
 			ch = ch >> 1;
 		}
 	}
@@ -758,11 +785,19 @@ AstNode *AstNode::mkconst_str(const std::string &str)
 bool AstNode::bits_only_01() const
 {
 	for (auto bit : bits)
-		if (bit != RTLIL::S0 && bit != RTLIL::S1)
+		if (bit != State::S0 && bit != State::S1)
 			return false;
 	return true;
 }
 
+RTLIL::Const AstNode::bitsAsUnsizedConst(int width)
+{
+	RTLIL::State extbit = bits.back();
+	while (width > int(bits.size()))
+		bits.push_back(extbit);
+	return RTLIL::Const(bits);
+}
+
 RTLIL::Const AstNode::bitsAsConst(int width, bool is_signed)
 {
 	std::vector<RTLIL::State> bits = this->bits;
@@ -895,9 +930,9 @@ RTLIL::Const AstNode::realAsConst(int width)
 }
 
 // create a new AstModule from an AST_MODULE AST node
-static AstModule* process_module(AstNode *ast, bool defer)
+static AstModule* process_module(AstNode *ast, bool defer, AstNode *original_ast = NULL)
 {
-	log_assert(ast->type == AST_MODULE);
+	log_assert(ast->type == AST_MODULE || ast->type == AST_INTERFACE);
 
 	if (defer)
 		log("Storing AST representation for module `%s'.\n", ast->str.c_str());
@@ -908,33 +943,116 @@ static AstModule* process_module(AstNode *ast, bool defer)
 	current_module->ast = NULL;
 	current_module->name = ast->str;
 	current_module->attributes["\\src"] = stringf("%s:%d", ast->filename.c_str(), ast->linenum);
+	current_module->set_bool_attribute("\\cells_not_processed");
 
 	current_ast_mod = ast;
-	AstNode *ast_before_simplify = ast->clone();
+	AstNode *ast_before_simplify;
+	if (original_ast != NULL)
+		ast_before_simplify = original_ast;
+	else
+		ast_before_simplify = ast->clone();
 
 	if (flag_dump_ast1) {
-		log("Dumping Verilog AST before simplification:\n");
+		log("Dumping AST before simplification:\n");
 		ast->dumpAst(NULL, "    ");
 		log("--- END OF AST DUMP ---\n");
 	}
+	if (flag_dump_vlog1) {
+		log("Dumping Verilog AST before simplification:\n");
+		ast->dumpVlog(NULL, "    ");
+		log("--- END OF AST DUMP ---\n");
+	}
 
 	if (!defer)
 	{
+		bool blackbox_module = flag_lib;
+
+		if (!blackbox_module && !flag_noblackbox) {
+			blackbox_module = true;
+			for (auto child : ast->children) {
+				if (child->type == AST_WIRE && (child->is_input || child->is_output))
+					continue;
+				if (child->type == AST_PARAMETER || child->type == AST_LOCALPARAM)
+					continue;
+				if (child->type == AST_CELL && child->children.size() > 0 && child->children[0]->type == AST_CELLTYPE &&
+						(child->children[0]->str == "$specify2" || child->children[0]->str == "$specify3" || child->children[0]->str == "$specrule"))
+					continue;
+				blackbox_module = false;
+				break;
+			}
+		}
+
 		while (ast->simplify(!flag_noopt, false, false, 0, -1, false, false)) { }
 
 		if (flag_dump_ast2) {
-			log("Dumping Verilog AST after simplification:\n");
+			log("Dumping AST after simplification:\n");
 			ast->dumpAst(NULL, "    ");
 			log("--- END OF AST DUMP ---\n");
 		}
 
-		if (flag_dump_vlog) {
-			log("Dumping Verilog AST (as requested by dump_vlog option):\n");
+		if (flag_dump_vlog2) {
+			log("Dumping Verilog AST after simplification:\n");
 			ast->dumpVlog(NULL, "    ");
 			log("--- END OF AST DUMP ---\n");
 		}
 
-		if (flag_lib) {
+		if (flag_nowb && ast->attributes.count("\\whitebox")) {
+			delete ast->attributes.at("\\whitebox");
+			ast->attributes.erase("\\whitebox");
+		}
+
+		if (ast->attributes.count("\\lib_whitebox")) {
+			if (!flag_lib || flag_nowb) {
+				delete ast->attributes.at("\\lib_whitebox");
+				ast->attributes.erase("\\lib_whitebox");
+			} else {
+				if (ast->attributes.count("\\whitebox")) {
+					delete ast->attributes.at("\\whitebox");
+					ast->attributes.erase("\\whitebox");
+				}
+				AstNode *n = ast->attributes.at("\\lib_whitebox");
+				ast->attributes["\\whitebox"] = n;
+				ast->attributes.erase("\\lib_whitebox");
+			}
+		}
+
+		if (!blackbox_module && ast->attributes.count("\\blackbox")) {
+			AstNode *n = ast->attributes.at("\\blackbox");
+			if (n->type != AST_CONSTANT)
+				log_file_error(ast->filename, ast->linenum, "Got blackbox attribute with non-constant value!\n");
+			blackbox_module = n->asBool();
+		}
+
+		if (blackbox_module && ast->attributes.count("\\whitebox")) {
+			AstNode *n = ast->attributes.at("\\whitebox");
+			if (n->type != AST_CONSTANT)
+				log_file_error(ast->filename, ast->linenum, "Got whitebox attribute with non-constant value!\n");
+			blackbox_module = !n->asBool();
+		}
+
+		if (ast->attributes.count("\\noblackbox")) {
+			if (blackbox_module) {
+				AstNode *n = ast->attributes.at("\\noblackbox");
+				if (n->type != AST_CONSTANT)
+					log_file_error(ast->filename, ast->linenum, "Got noblackbox attribute with non-constant value!\n");
+				blackbox_module = !n->asBool();
+			}
+			delete ast->attributes.at("\\noblackbox");
+			ast->attributes.erase("\\noblackbox");
+		}
+
+		if (blackbox_module)
+		{
+			if (ast->attributes.count("\\whitebox")) {
+				delete ast->attributes.at("\\whitebox");
+				ast->attributes.erase("\\whitebox");
+			}
+
+			if (ast->attributes.count("\\lib_whitebox")) {
+				delete ast->attributes.at("\\lib_whitebox");
+				ast->attributes.erase("\\lib_whitebox");
+			}
+
 			std::vector<AstNode*> new_children;
 			for (auto child : ast->children) {
 				if (child->type == AST_WIRE && (child->is_input || child->is_output)) {
@@ -943,20 +1061,26 @@ static AstModule* process_module(AstNode *ast, bool defer)
 					child->delete_children();
 					child->children.push_back(AstNode::mkconst_int(0, false, 0));
 					new_children.push_back(child);
+				} else if (child->type == AST_CELL && child->children.size() > 0 && child->children[0]->type == AST_CELLTYPE &&
+						(child->children[0]->str == "$specify2" || child->children[0]->str == "$specify3" || child->children[0]->str == "$specrule")) {
+					new_children.push_back(child);
 				} else {
 					delete child;
 				}
 			}
+
 			ast->children.swap(new_children);
-			ast->attributes["\\blackbox"] = AstNode::mkconst_int(1, false);
+
+			if (ast->attributes.count("\\blackbox") == 0) {
+				ast->attributes["\\blackbox"] = AstNode::mkconst_int(1, false);
+			}
 		}
 
 		ignoreThisSignalsInInitial = RTLIL::SigSpec();
 
 		for (auto &attr : ast->attributes) {
 			if (attr.second->type != AST_CONSTANT)
-				log_error("Attribute `%s' with non-constant value at %s:%d!\n",
-						attr.first.c_str(), ast->filename.c_str(), ast->linenum);
+				log_file_error(ast->filename, ast->linenum, "Attribute `%s' with non-constant value!\n", attr.first.c_str());
 			current_module->attributes[attr.first] = attr.second->asAttrConst();
 		}
 		for (size_t i = 0; i < ast->children.size(); i++) {
@@ -980,15 +1104,27 @@ static AstModule* process_module(AstNode *ast, bool defer)
 
 		ignoreThisSignalsInInitial = RTLIL::SigSpec();
 	}
+	else {
+		for (auto &attr : ast->attributes) {
+			if (attr.second->type != AST_CONSTANT)
+				continue;
+			current_module->attributes[attr.first] = attr.second->asAttrConst();
+		}
+	}
 
+	if (ast->type == AST_INTERFACE)
+		current_module->set_bool_attribute("\\is_interface");
 	current_module->ast = ast_before_simplify;
 	current_module->nolatches = flag_nolatches;
 	current_module->nomeminit = flag_nomeminit;
 	current_module->nomem2reg = flag_nomem2reg;
 	current_module->mem2reg = flag_mem2reg;
+	current_module->noblackbox = flag_noblackbox;
 	current_module->lib = flag_lib;
+	current_module->nowb = flag_nowb;
 	current_module->noopt = flag_noopt;
 	current_module->icells = flag_icells;
+	current_module->pwires = flag_pwires;
 	current_module->autowire = flag_autowire;
 	current_module->fixup_ports();
 
@@ -1002,27 +1138,32 @@ static AstModule* process_module(AstNode *ast, bool defer)
 }
 
 // create AstModule instances for all modules in the AST tree and add them to 'design'
-void AST::process(RTLIL::Design *design, AstNode *ast, bool dump_ast1, bool dump_ast2, bool dump_vlog, bool dump_rtlil,
-		bool nolatches, bool nomeminit, bool nomem2reg, bool mem2reg, bool lib, bool noopt, bool icells, bool nooverwrite, bool overwrite, bool defer, bool autowire)
+void AST::process(RTLIL::Design *design, AstNode *ast, bool dump_ast1, bool dump_ast2, bool no_dump_ptr, bool dump_vlog1, bool dump_vlog2, bool dump_rtlil,
+		bool nolatches, bool nomeminit, bool nomem2reg, bool mem2reg, bool noblackbox, bool lib, bool nowb, bool noopt, bool icells, bool pwires, bool nooverwrite, bool overwrite, bool defer, bool autowire)
 {
 	current_ast = ast;
 	flag_dump_ast1 = dump_ast1;
 	flag_dump_ast2 = dump_ast2;
-	flag_dump_vlog = dump_vlog;
+	flag_no_dump_ptr = no_dump_ptr;
+	flag_dump_vlog1 = dump_vlog1;
+	flag_dump_vlog2 = dump_vlog2;
 	flag_dump_rtlil = dump_rtlil;
 	flag_nolatches = nolatches;
 	flag_nomeminit = nomeminit;
 	flag_nomem2reg = nomem2reg;
 	flag_mem2reg = mem2reg;
+	flag_noblackbox = noblackbox;
 	flag_lib = lib;
+	flag_nowb = nowb;
 	flag_noopt = noopt;
 	flag_icells = icells;
+	flag_pwires = pwires;
 	flag_autowire = autowire;
 
 	log_assert(current_ast->type == AST_DESIGN);
 	for (auto it = current_ast->children.begin(); it != current_ast->children.end(); it++)
 	{
-		if ((*it)->type == AST_MODULE)
+		if ((*it)->type == AST_MODULE || (*it)->type == AST_INTERFACE)
 		{
 			for (auto n : design->verilog_globals)
 				(*it)->children.push_back(n->clone());
@@ -1035,7 +1176,7 @@ void AST::process(RTLIL::Design *design, AstNode *ast, bool dump_ast1, bool dump
 				}
 			}
 
-			if (flag_icells && (*it)->str.substr(0, 2) == "\\$")
+			if (flag_icells && (*it)->str.compare(0, 2, "\\$") == 0)
 				(*it)->str = (*it)->str.substr(1);
 
 			if (defer)
@@ -1043,9 +1184,8 @@ void AST::process(RTLIL::Design *design, AstNode *ast, bool dump_ast1, bool dump
 
 			if (design->has((*it)->str)) {
 				RTLIL::Module *existing_mod = design->module((*it)->str);
-				if (!nooverwrite && !overwrite && !existing_mod->get_bool_attribute("\\blackbox")) {
-					log_error("Re-definition of module `%s' at %s:%d!\n",
-							(*it)->str.c_str(), (*it)->filename.c_str(), (*it)->linenum);
+				if (!nooverwrite && !overwrite && !existing_mod->get_blackbox_attribute()) {
+					log_file_error((*it)->filename, (*it)->linenum, "Re-definition of module `%s'!\n", (*it)->str.c_str());
 				} else if (nooverwrite) {
 					log("Ignoring re-definition of module `%s' at %s:%d.\n",
 							(*it)->str.c_str(), (*it)->filename.c_str(), (*it)->linenum);
@@ -1074,29 +1214,274 @@ AstModule::~AstModule()
 		delete ast;
 }
 
+
+// An interface port with modport is specified like this:
+//    <interface_name>.<modport_name>
+// This function splits the interface_name from the modport_name, and fails if it is not a valid combination
+std::pair<std::string,std::string> AST::split_modport_from_type(std::string name_type)
+{
+	std::string interface_type = "";
+	std::string interface_modport = "";
+	size_t ndots = std::count(name_type.begin(), name_type.end(), '.');
+	// Separate the interface instance name from any modports:
+	if (ndots == 0) { // Does not have modport
+		interface_type = name_type;
+	}
+	else {
+		std::stringstream name_type_stream(name_type);
+		std::string segment;
+		std::vector<std::string> seglist;
+		while(std::getline(name_type_stream, segment, '.')) {
+			seglist.push_back(segment);
+		}
+		if (ndots == 1) { // Has modport
+			interface_type = seglist[0];
+			interface_modport = seglist[1];
+		}
+		else { // Erroneous port type
+			log_error("More than two '.' in signal port type (%s)\n", name_type.c_str());
+		}
+	}
+	return std::pair<std::string,std::string>(interface_type, interface_modport);
+
+}
+
+AstNode * AST::find_modport(AstNode *intf, std::string name)
+{
+	for (auto &ch : intf->children)
+		if (ch->type == AST_MODPORT)
+			if (ch->str == name) // Modport found
+				return ch;
+	return NULL;
+}
+
+// Iterate over all wires in an interface and add them as wires in the AST module:
+void AST::explode_interface_port(AstNode *module_ast, RTLIL::Module * intfmodule, std::string intfname, AstNode *modport)
+{
+	for (auto &wire_it : intfmodule->wires_){
+		AstNode *wire = new AstNode(AST_WIRE, new AstNode(AST_RANGE, AstNode::mkconst_int(wire_it.second->width -1, true), AstNode::mkconst_int(0, true)));
+		std::string origname = log_id(wire_it.first);
+		std::string newname = intfname + "." + origname;
+		wire->str = newname;
+		if (modport != NULL) {
+			bool found_in_modport = false;
+			// Search for the current wire in the wire list for the current modport
+			for (auto &ch : modport->children) {
+				if (ch->type == AST_MODPORTMEMBER) {
+					std::string compare_name = "\\" + origname;
+					if (ch->str == compare_name) { // Found signal. The modport decides whether it is input or output
+						found_in_modport = true;
+						wire->is_input = ch->is_input;
+						wire->is_output = ch->is_output;
+						break;
+					}
+				}
+			}
+			if (found_in_modport) {
+				module_ast->children.push_back(wire);
+			}
+			else { // If not found in modport, do not create port
+				delete wire;
+			}
+		}
+		else { // If no modport, set inout
+			wire->is_input = true;
+			wire->is_output = true;
+			module_ast->children.push_back(wire);
+		}
+	}
+}
+
+// When an interface instance is found in a module, the whole RTLIL for the module will be rederived again
+// from AST. The interface members are copied into the AST module with the prefix of the interface.
+void AstModule::reprocess_module(RTLIL::Design *design, dict<RTLIL::IdString, RTLIL::Module*> local_interfaces)
+{
+	loadconfig();
+
+	bool is_top = false;
+	AstNode *new_ast = ast->clone();
+	for (auto &intf : local_interfaces) {
+		std::string intfname = intf.first.str();
+		RTLIL::Module *intfmodule = intf.second;
+		for (auto &wire_it : intfmodule->wires_){
+			AstNode *wire = new AstNode(AST_WIRE, new AstNode(AST_RANGE, AstNode::mkconst_int(wire_it.second->width -1, true), AstNode::mkconst_int(0, true)));
+			std::string newname = log_id(wire_it.first);
+			newname = intfname + "." + newname;
+			wire->str = newname;
+			new_ast->children.push_back(wire);
+		}
+	}
+
+	AstNode *ast_before_replacing_interface_ports = new_ast->clone();
+
+	// Explode all interface ports. Note this will only have an effect on 'top
+	// level' modules. Other sub-modules will have their interface ports
+	// exploded via the derive(..) function
+	for (size_t i =0; i<new_ast->children.size(); i++)
+	{
+		AstNode *ch2 = new_ast->children[i];
+		if (ch2->type == AST_INTERFACEPORT) { // Is an interface port
+			std::string name_port = ch2->str; // Name of the interface port
+			if (ch2->children.size() > 0) {
+				for(size_t j=0; j<ch2->children.size();j++) {
+					AstNode *ch = ch2->children[j];
+					if(ch->type == AST_INTERFACEPORTTYPE) { // Found the AST node containing the type of the interface
+						std::pair<std::string,std::string> res = split_modport_from_type(ch->str);
+						std::string interface_type = res.first;
+						std::string interface_modport = res.second; // Is "", if no modport
+						if (design->modules_.count(interface_type) > 0) {
+							// Add a cell to the module corresponding to the interface port such that
+							// it can further propagated down if needed:
+							AstNode *celltype_for_intf = new AstNode(AST_CELLTYPE);
+							celltype_for_intf->str = interface_type;
+							AstNode *cell_for_intf = new AstNode(AST_CELL, celltype_for_intf);
+							cell_for_intf->str = name_port + "_inst_from_top_dummy";
+							new_ast->children.push_back(cell_for_intf);
+
+							// Get all members of this non-overridden dummy interface instance:
+							RTLIL::Module *intfmodule = design->modules_[interface_type]; // All interfaces should at this point in time (assuming
+							                                                              // reprocess_module is called from the hierarchy pass) be
+							                                                              // present in design->modules_
+							AstModule *ast_module_of_interface = (AstModule*)intfmodule;
+							std::string interface_modport_compare_str = "\\" + interface_modport;
+							AstNode *modport = find_modport(ast_module_of_interface->ast, interface_modport_compare_str); // modport == NULL if no modport
+							// Iterate over all wires in the interface and add them to the module:
+							explode_interface_port(new_ast, intfmodule, name_port, modport);
+						}
+						break;
+					}
+				}
+			}
+		}
+	}
+
+	// The old module will be deleted. Rename and mark for deletion:
+	std::string original_name = this->name.str();
+	std::string changed_name = original_name + "_before_replacing_local_interfaces";
+	design->rename(this, changed_name);
+	this->set_bool_attribute("\\to_delete");
+
+	// Check if the module was the top module. If it was, we need to remove the top attribute and put it on the
+	// new module.
+	if (this->get_bool_attribute("\\initial_top")) {
+		this->attributes.erase("\\initial_top");
+		is_top = true;
+	}
+
+	// Generate RTLIL from AST for the new module and add to the design:
+	AstModule *newmod = process_module(new_ast, false, ast_before_replacing_interface_ports);
+	delete(new_ast);
+	design->add(newmod);
+	RTLIL::Module* mod = design->module(original_name);
+	if (is_top)
+		mod->set_bool_attribute("\\top");
+
+	// Set the attribute "interfaces_replaced_in_module" so that it does not happen again.
+	mod->set_bool_attribute("\\interfaces_replaced_in_module");
+}
+
+// create a new parametric module (when needed) and return the name of the generated module - WITH support for interfaces
+// This method is used to explode the interface when the interface is a port of the module (not instantiated inside)
+RTLIL::IdString AstModule::derive(RTLIL::Design *design, dict<RTLIL::IdString, RTLIL::Const> parameters, dict<RTLIL::IdString, RTLIL::Module*> interfaces, dict<RTLIL::IdString, RTLIL::IdString> modports, bool mayfail)
+{
+	AstNode *new_ast = NULL;
+	std::string modname = derive_common(design, parameters, &new_ast, mayfail);
+
+	// Since interfaces themselves may be instantiated with different parameters,
+	// "modname" must also take those into account, so that unique modules
+	// are derived for any variant of interface connections:
+	std::string interf_info = "";
+
+	bool has_interfaces = false;
+	for(auto &intf : interfaces) {
+		interf_info += log_id(intf.second->name);
+		has_interfaces = true;
+	}
+
+	if (has_interfaces)
+		modname += "$interfaces$" + interf_info;
+
+
+	if (!design->has(modname)) {
+		new_ast->str = modname;
+
+		// Iterate over all interfaces which are ports in this module:
+		for(auto &intf : interfaces) {
+			RTLIL::Module * intfmodule = intf.second;
+			std::string intfname = intf.first.str();
+			// Check if a modport applies for the interface port:
+			AstNode *modport = NULL;
+			if (modports.count(intfname) > 0) {
+				std::string interface_modport = modports.at(intfname).str();
+				AstModule *ast_module_of_interface = (AstModule*)intfmodule;
+				AstNode *ast_node_of_interface = ast_module_of_interface->ast;
+				modport = find_modport(ast_node_of_interface, interface_modport);
+			}
+			// Iterate over all wires in the interface and add them to the module:
+			explode_interface_port(new_ast, intfmodule, intfname, modport);
+		}
+
+		design->add(process_module(new_ast, false));
+		design->module(modname)->check();
+
+		RTLIL::Module* mod = design->module(modname);
+
+		// Now that the interfaces have been exploded, we can delete the dummy port related to every interface.
+		for(auto &intf : interfaces) {
+			if(mod->wires_.count(intf.first)) {
+				mod->wires_.erase(intf.first);
+				mod->fixup_ports();
+				// We copy the cell of the interface to the sub-module such that it can further be found if it is propagated
+				// down to sub-sub-modules etc.
+				RTLIL::Cell * new_subcell = mod->addCell(intf.first, intf.second->name);
+				new_subcell->set_bool_attribute("\\is_interface");
+			}
+			else {
+				log_error("No port with matching name found (%s) in %s. Stopping\n", log_id(intf.first), modname.c_str());
+			}
+		}
+
+		// If any interfaces were replaced, set the attribute 'interfaces_replaced_in_module':
+		if (interfaces.size() > 0) {
+			mod->set_bool_attribute("\\interfaces_replaced_in_module");
+		}
+
+	} else {
+		log("Found cached RTLIL representation for module `%s'.\n", modname.c_str());
+	}
+
+	delete new_ast;
+	return modname;
+}
+
+// create a new parametric module (when needed) and return the name of the generated module - without support for interfaces
+RTLIL::IdString AstModule::derive(RTLIL::Design *design, dict<RTLIL::IdString, RTLIL::Const> parameters, bool mayfail)
+{
+	AstNode *new_ast = NULL;
+	std::string modname = derive_common(design, parameters, &new_ast, mayfail);
+
+	if (!design->has(modname)) {
+		new_ast->str = modname;
+		design->add(process_module(new_ast, false));
+		design->module(modname)->check();
+	} else {
+		log("Found cached RTLIL representation for module `%s'.\n", modname.c_str());
+	}
+
+	delete new_ast;
+	return modname;
+}
+
 // create a new parametric module (when needed) and return the name of the generated module
-RTLIL::IdString AstModule::derive(RTLIL::Design *design, dict<RTLIL::IdString, RTLIL::Const> parameters, bool)
+std::string AstModule::derive_common(RTLIL::Design *design, dict<RTLIL::IdString, RTLIL::Const> parameters, AstNode **new_ast_out, bool)
 {
 	std::string stripped_name = name.str();
 
-	if (stripped_name.substr(0, 9) == "$abstract")
+	if (stripped_name.compare(0, 9, "$abstract") == 0)
 		stripped_name = stripped_name.substr(9);
 
 	log_header(design, "Executing AST frontend in derive mode using pre-parsed AST for module `%s'.\n", stripped_name.c_str());
-
-	current_ast = NULL;
-	flag_dump_ast1 = false;
-	flag_dump_ast2 = false;
-	flag_dump_vlog = false;
-	flag_nolatches = nolatches;
-	flag_nomeminit = nomeminit;
-	flag_nomem2reg = nomem2reg;
-	flag_mem2reg = mem2reg;
-	flag_lib = lib;
-	flag_noopt = noopt;
-	flag_icells = icells;
-	flag_autowire = autowire;
-	use_internal_line_num();
+	loadconfig();
 
 	std::string para_info;
 	AstNode *new_ast = ast->clone();
@@ -1114,7 +1499,10 @@ RTLIL::IdString AstModule::derive(RTLIL::Design *design, dict<RTLIL::IdString, R
 	rewrite_parameter:
 			para_info += stringf("%s=%s", child->str.c_str(), log_signal(RTLIL::SigSpec(parameters[para_id])));
 			delete child->children.at(0);
-			if ((parameters[para_id].flags & RTLIL::CONST_FLAG_STRING) != 0)
+			if ((parameters[para_id].flags & RTLIL::CONST_FLAG_REAL) != 0) {
+				child->children[0] = new AstNode(AST_REALVALUE);
+				child->children[0]->realvalue = std::stod(parameters[para_id].decode_string());
+			} else if ((parameters[para_id].flags & RTLIL::CONST_FLAG_STRING) != 0)
 				child->children[0] = AstNode::mkconst_str(parameters[para_id].decode_string());
 			else
 				child->children[0] = AstNode::mkconst_bits(parameters[para_id].bits, (parameters[para_id].flags & RTLIL::CONST_FLAG_SIGNED) != 0);
@@ -1147,15 +1535,8 @@ RTLIL::IdString AstModule::derive(RTLIL::Design *design, dict<RTLIL::IdString, R
 	else
 		modname = "$paramod" + stripped_name + para_info;
 
-	if (!design->has(modname)) {
-		new_ast->str = modname;
-		design->add(process_module(new_ast, false));
-		design->module(modname)->check();
-	} else {
-		log("Found cached RTLIL representation for module `%s'.\n", modname.c_str());
-	}
 
-	delete new_ast;
+	(*new_ast_out) = new_ast;
 	return modname;
 }
 
@@ -1170,14 +1551,38 @@ RTLIL::Module *AstModule::clone() const
 	new_mod->nomeminit = nomeminit;
 	new_mod->nomem2reg = nomem2reg;
 	new_mod->mem2reg = mem2reg;
+	new_mod->noblackbox = noblackbox;
 	new_mod->lib = lib;
+	new_mod->nowb = nowb;
 	new_mod->noopt = noopt;
 	new_mod->icells = icells;
+	new_mod->pwires = pwires;
 	new_mod->autowire = autowire;
 
 	return new_mod;
 }
 
+void AstModule::loadconfig() const
+{
+	current_ast = NULL;
+	flag_dump_ast1 = false;
+	flag_dump_ast2 = false;
+	flag_dump_vlog1 = false;
+	flag_dump_vlog2 = false;
+	flag_nolatches = nolatches;
+	flag_nomeminit = nomeminit;
+	flag_nomem2reg = nomem2reg;
+	flag_mem2reg = mem2reg;
+	flag_noblackbox = noblackbox;
+	flag_lib = lib;
+	flag_nowb = nowb;
+	flag_noopt = noopt;
+	flag_icells = icells;
+	flag_pwires = pwires;
+	flag_autowire = autowire;
+	use_internal_line_num();
+}
+
 // internal dummy line number callbacks
 namespace {
 	int internal_line_num;
@@ -1197,4 +1602,3 @@ void AST::use_internal_line_num()
 }
 
 YOSYS_NAMESPACE_END
-
diff --git a/frontends/ast/ast.h b/frontends/ast/ast.h
index 756629aca..93fee913e 100644
--- a/frontends/ast/ast.h
+++ b/frontends/ast/ast.h
@@ -1,4 +1,4 @@
-/*
+/* -*- c++ -*-
  *  yosys -- Yosys Open SYnthesis Suite
  *
  *  Copyright (C) 2012  Clifford Wolf <clifford@clifford.at>
@@ -137,11 +137,17 @@ namespace AST
 		AST_GENIF,
 		AST_GENCASE,
 		AST_GENBLOCK,
-
+		AST_TECALL,
+		
 		AST_POSEDGE,
 		AST_NEGEDGE,
 		AST_EDGE,
 
+		AST_INTERFACE,
+		AST_INTERFACEPORT,
+		AST_INTERFACEPORTTYPE,
+		AST_MODPORT,
+		AST_MODPORTMEMBER,
 		AST_PACKAGE
 	};
 
@@ -168,7 +174,7 @@ namespace AST
 		// node content - most of it is unused in most node types
 		std::string str;
 		std::vector<RTLIL::State> bits;
-		bool is_input, is_output, is_reg, is_signed, is_string, range_valid, range_swapped;
+		bool is_input, is_output, is_reg, is_logic, is_signed, is_string, is_wand, is_wor, range_valid, range_swapped, was_checked, is_unsized;
 		int port_id, range_left, range_right;
 		uint32_t integer;
 		double realvalue;
@@ -209,6 +215,8 @@ namespace AST
 			MEM2REG_FL_SET_ASYNC = 0x00000800,
 			MEM2REG_FL_EQ2       = 0x00001000,
 			MEM2REG_FL_CMPLX_LHS = 0x00002000,
+			MEM2REG_FL_CONST_LHS = 0x00004000,
+			MEM2REG_FL_VAR_LHS   = 0x00008000,
 
 			/* proc flags */
 			MEM2REG_FL_EQ1       = 0x01000000,
@@ -232,6 +240,7 @@ namespace AST
 		bool has_const_only_constructs(bool &recommend_const_eval);
 		void replace_variables(std::map<std::string, varinfo_t> &variables, AstNode *fcall);
 		AstNode *eval_const_function(AstNode *fcall);
+		bool is_simple_const_expr();
 
 		// create a human-readable text representation of the AST (for debugging)
 		void dumpAst(FILE *f, std::string indent) const;
@@ -254,6 +263,7 @@ namespace AST
 
 		// helper functions for creating AST nodes for constants
 		static AstNode *mkconst_int(uint32_t v, bool is_signed, int width = 32);
+		static AstNode *mkconst_bits(const std::vector<RTLIL::State> &v, bool is_signed, bool is_unsized);
 		static AstNode *mkconst_bits(const std::vector<RTLIL::State> &v, bool is_signed);
 		static AstNode *mkconst_str(const std::vector<RTLIL::State> &v);
 		static AstNode *mkconst_str(const std::string &str);
@@ -261,6 +271,7 @@ namespace AST
 		// helper function for creating sign-extended const objects
 		RTLIL::Const bitsAsConst(int width, bool is_signed);
 		RTLIL::Const bitsAsConst(int width = -1);
+		RTLIL::Const bitsAsUnsizedConst(int width);
 		RTLIL::Const asAttrConst();
 		RTLIL::Const asParaConst();
 		uint64_t asInt(bool is_signed);
@@ -274,17 +285,21 @@ namespace AST
 	};
 
 	// process an AST tree (ast must point to an AST_DESIGN node) and generate RTLIL code
-	void process(RTLIL::Design *design, AstNode *ast, bool dump_ast1, bool dump_ast2, bool dump_vlog, bool dump_rtlil, bool nolatches, bool nomeminit,
-			bool nomem2reg, bool mem2reg, bool lib, bool noopt, bool icells, bool nooverwrite, bool overwrite, bool defer, bool autowire);
+	void process(RTLIL::Design *design, AstNode *ast, bool dump_ast1, bool dump_ast2, bool no_dump_ptr, bool dump_vlog1, bool dump_vlog2, bool dump_rtlil, bool nolatches, bool nomeminit,
+			bool nomem2reg, bool mem2reg, bool noblackbox, bool lib, bool nowb, bool noopt, bool icells, bool pwires, bool nooverwrite, bool overwrite, bool defer, bool autowire);
 
 	// parametric modules are supported directly by the AST library
 	// therefore we need our own derivate of RTLIL::Module with overloaded virtual functions
 	struct AstModule : RTLIL::Module {
 		AstNode *ast;
-		bool nolatches, nomeminit, nomem2reg, mem2reg, lib, noopt, icells, autowire;
-		virtual ~AstModule();
-		virtual RTLIL::IdString derive(RTLIL::Design *design, dict<RTLIL::IdString, RTLIL::Const> parameters, bool mayfail);
-		virtual RTLIL::Module *clone() const;
+		bool nolatches, nomeminit, nomem2reg, mem2reg, noblackbox, lib, nowb, noopt, icells, pwires, autowire;
+		~AstModule() YS_OVERRIDE;
+		RTLIL::IdString derive(RTLIL::Design *design, dict<RTLIL::IdString, RTLIL::Const> parameters, bool mayfail) YS_OVERRIDE;
+		RTLIL::IdString derive(RTLIL::Design *design, dict<RTLIL::IdString, RTLIL::Const> parameters, dict<RTLIL::IdString, RTLIL::Module*> interfaces, dict<RTLIL::IdString, RTLIL::IdString> modports, bool mayfail) YS_OVERRIDE;
+		std::string derive_common(RTLIL::Design *design, dict<RTLIL::IdString, RTLIL::Const> parameters, AstNode **new_ast_out, bool mayfail);
+		void reprocess_module(RTLIL::Design *design, dict<RTLIL::IdString, RTLIL::Module *> local_interfaces) YS_OVERRIDE;
+		RTLIL::Module *clone() const YS_OVERRIDE;
+		void loadconfig() const;
 	};
 
 	// this must be set by the language frontend before parsing the sources
@@ -300,13 +315,18 @@ namespace AST
 
 	// call a DPI function
 	AstNode *dpi_call(const std::string &rtype, const std::string &fname, const std::vector<std::string> &argtypes, const std::vector<AstNode*> &args);
+
+	// Helper functions related to handling SystemVerilog interfaces
+	std::pair<std::string,std::string> split_modport_from_type(std::string name_type);
+	AstNode * find_modport(AstNode *intf, std::string name);
+	void explode_interface_port(AstNode *module_ast, RTLIL::Module * intfmodule, std::string intfname, AstNode *modport);
 }
 
 namespace AST_INTERNAL
 {
 	// internal state variables
-	extern bool flag_dump_ast1, flag_dump_ast2, flag_dump_rtlil, flag_nolatches, flag_nomeminit;
-	extern bool flag_nomem2reg, flag_mem2reg, flag_lib, flag_noopt, flag_icells, flag_autowire;
+	extern bool flag_dump_ast1, flag_dump_ast2, flag_no_dump_ptr, flag_dump_rtlil, flag_nolatches, flag_nomeminit;
+	extern bool flag_nomem2reg, flag_mem2reg, flag_lib, flag_noopt, flag_icells, flag_pwires, flag_autowire;
 	extern AST::AstNode *current_ast, *current_ast_mod;
 	extern std::map<std::string, AST::AstNode*> current_scope;
 	extern const dict<RTLIL::SigBit, RTLIL::SigBit> *genRTLIL_subst_ptr;
diff --git a/frontends/ast/genrtlil.cc b/frontends/ast/genrtlil.cc
index d9f0039af..407a34472 100644
--- a/frontends/ast/genrtlil.cc
+++ b/frontends/ast/genrtlil.cc
@@ -55,8 +55,7 @@ static RTLIL::SigSpec uniop2rtlil(AstNode *that, std::string type, int result_wi
 	if (gen_attributes)
 		for (auto &attr : that->attributes) {
 			if (attr.second->type != AST_CONSTANT)
-				log_error("Attribute `%s' with non-constant value at %s:%d!\n",
-						attr.first.c_str(), that->filename.c_str(), that->linenum);
+				log_file_error(that->filename, that->linenum, "Attribute `%s' with non-constant value!\n", attr.first.c_str());
 			cell->attributes[attr.first] = attr.second->asAttrConst();
 		}
 
@@ -89,8 +88,7 @@ static void widthExtend(AstNode *that, RTLIL::SigSpec &sig, int width, bool is_s
 	if (that != NULL)
 		for (auto &attr : that->attributes) {
 			if (attr.second->type != AST_CONSTANT)
-				log_error("Attribute `%s' with non-constant value at %s:%d!\n",
-						attr.first.c_str(), that->filename.c_str(), that->linenum);
+				log_file_error(that->filename, that->linenum, "Attribute `%s' with non-constant value!\n", attr.first.c_str());
 			cell->attributes[attr.first] = attr.second->asAttrConst();
 		}
 
@@ -117,8 +115,7 @@ static RTLIL::SigSpec binop2rtlil(AstNode *that, std::string type, int result_wi
 
 	for (auto &attr : that->attributes) {
 		if (attr.second->type != AST_CONSTANT)
-			log_error("Attribute `%s' with non-constant value at %s:%d!\n",
-					attr.first.c_str(), that->filename.c_str(), that->linenum);
+			log_file_error(that->filename, that->linenum, "Attribute `%s' with non-constant value!\n", attr.first.c_str());
 		cell->attributes[attr.first] = attr.second->asAttrConst();
 	}
 
@@ -152,8 +149,7 @@ static RTLIL::SigSpec mux2rtlil(AstNode *that, const RTLIL::SigSpec &cond, const
 
 	for (auto &attr : that->attributes) {
 		if (attr.second->type != AST_CONSTANT)
-			log_error("Attribute `%s' with non-constant value at %s:%d!\n",
-					attr.first.c_str(), that->filename.c_str(), that->linenum);
+			log_file_error(that->filename, that->linenum, "Attribute `%s' with non-constant value!\n", attr.first.c_str());
 		cell->attributes[attr.first] = attr.second->asAttrConst();
 	}
 
@@ -207,8 +203,8 @@ struct AST_INTERNAL::ProcessGenerator
 		proc->name = stringf("$proc$%s:%d$%d", always->filename.c_str(), always->linenum, autoidx++);
 		for (auto &attr : always->attributes) {
 			if (attr.second->type != AST_CONSTANT)
-				log_error("Attribute `%s' with non-constant value at %s:%d!\n",
-						attr.first.c_str(), always->filename.c_str(), always->linenum);
+				log_file_error(always->filename, always->linenum, "Attribute `%s' with non-constant value!\n",
+						attr.first.c_str());
 			proc->attributes[attr.first] = attr.second->asAttrConst();
 		}
 		current_module->processes[proc->name] = proc;
@@ -238,7 +234,7 @@ struct AST_INTERNAL::ProcessGenerator
 
 		if (found_anyedge_syncs) {
 			if (found_global_syncs)
-				log_error("Found non-synthesizable event list at %s:%d!\n", always->filename.c_str(), always->linenum);
+				log_file_error(always->filename, always->linenum, "Found non-synthesizable event list!\n");
 			log("Note: Assuming pure combinatorial block at %s:%d in\n", always->filename.c_str(), always->linenum);
 			log("compliance with IEC 62142(E):2005 / IEEE Std. 1364.1(E):2002. Recommending\n");
 			log("use of @* instead of @(...) for better match of synthesis and simulation.\n");
@@ -253,12 +249,12 @@ struct AST_INTERNAL::ProcessGenerator
 					continue;
 				found_clocked_sync = true;
 				if (found_global_syncs || found_anyedge_syncs)
-					log_error("Found non-synthesizable event list at %s:%d!\n", always->filename.c_str(), always->linenum);
+					log_file_error(always->filename, always->linenum, "Found non-synthesizable event list!\n");
 				RTLIL::SyncRule *syncrule = new RTLIL::SyncRule;
 				syncrule->type = child->type == AST_POSEDGE ? RTLIL::STp : RTLIL::STn;
 				syncrule->signal = child->children[0]->genRTLIL();
 				if (GetSize(syncrule->signal) != 1)
-					log_error("Found posedge/negedge event on a signal that is not 1 bit wide at %s:%d!\n", always->filename.c_str(), always->linenum);
+					log_file_error(always->filename, always->linenum, "Found posedge/negedge event on a signal that is not 1 bit wide!\n");
 				addChunkActions(syncrule->actions, subst_lvalue_from, subst_lvalue_to, true);
 				proc->syncs.push_back(syncrule);
 			}
@@ -480,8 +476,7 @@ struct AST_INTERNAL::ProcessGenerator
 
 				for (auto &attr : ast->attributes) {
 					if (attr.second->type != AST_CONSTANT)
-						log_error("Attribute `%s' with non-constant value at %s:%d!\n",
-								attr.first.c_str(), ast->filename.c_str(), ast->linenum);
+						log_file_error(ast->filename, ast->linenum, "Attribute `%s' with non-constant value!\n", attr.first.c_str());
 					sw->attributes[attr.first] = attr.second->asAttrConst();
 				}
 
@@ -509,6 +504,7 @@ struct AST_INTERNAL::ProcessGenerator
 
 					RTLIL::CaseRule *backup_case = current_case;
 					current_case = new RTLIL::CaseRule;
+					current_case->attributes["\\src"] = stringf("%s:%d", child->filename.c_str(), child->linenum);
 					last_generated_case = current_case;
 					addChunkActions(current_case->actions, this_case_eq_ltemp, this_case_eq_rvalue);
 					for (auto node : child->children) {
@@ -530,7 +526,16 @@ struct AST_INTERNAL::ProcessGenerator
 				}
 
 				if (last_generated_case != NULL && ast->get_bool_attribute("\\full_case") && default_case == NULL) {
+			#if 0
+					// this is a valid transformation, but as optimization it is premature.
+					// better: add a default case that assigns 'x' to everything, and let later
+					// optimizations take care of the rest
 					last_generated_case->compare.clear();
+			#else
+					default_case = new RTLIL::CaseRule;
+					addChunkActions(default_case->actions, this_case_eq_ltemp, SigSpec(State::Sx, GetSize(this_case_eq_rvalue)));
+					sw->cases.push_back(default_case);
+			#endif
 				} else {
 					if (default_case == NULL) {
 						default_case = new RTLIL::CaseRule;
@@ -549,12 +554,16 @@ struct AST_INTERNAL::ProcessGenerator
 			break;
 
 		case AST_WIRE:
-			log_error("Found wire declaration in block without label at at %s:%d!\n", ast->filename.c_str(), ast->linenum);
+			log_file_error(ast->filename, ast->linenum, "Found reg declaration in block without label!\n");
+			break;
+
+		case AST_ASSIGN:
+			log_file_error(ast->filename, ast->linenum, "Found continous assignment in always/initial block!\n");
 			break;
 
 		case AST_PARAMETER:
 		case AST_LOCALPARAM:
-			log_error("Found parameter declaration in block without label at at %s:%d!\n", ast->filename.c_str(), ast->linenum);
+			log_file_error(ast->filename, ast->linenum, "Found parameter declaration in block without label!\n");
 			break;
 
 		case AST_NONE:
@@ -602,7 +611,7 @@ void AstNode::detectSignWidthWorker(int &width_hint, bool &sign_hint, bool *foun
 		if (id_ast == NULL && current_scope.count(str))
 			id_ast = current_scope.at(str);
 		if (!id_ast)
-			log_error("Failed to resolve identifier %s for width detection at %s:%d!\n", str.c_str(), filename.c_str(), linenum);
+			log_file_error(filename, linenum, "Failed to resolve identifier %s for width detection!\n", str.c_str());
 		if (id_ast->type == AST_PARAMETER || id_ast->type == AST_LOCALPARAM) {
 			if (id_ast->children.size() > 1 && id_ast->children[1]->range_valid) {
 				this_width = id_ast->children[1]->range_left - id_ast->children[1]->range_right + 1;
@@ -612,7 +621,7 @@ void AstNode::detectSignWidthWorker(int &width_hint, bool &sign_hint, bool *foun
 			if (id_ast->children[0]->type == AST_CONSTANT)
 				this_width = id_ast->children[0]->bits.size();
 			else
-				log_error("Failed to detect width for parameter %s at %s:%d!\n", str.c_str(), filename.c_str(), linenum);
+				log_file_error(filename, linenum, "Failed to detect width for parameter %s!\n", str.c_str());
 			if (children.size() != 0)
 				range = children[0];
 		} else if (id_ast->type == AST_WIRE || id_ast->type == AST_AUTOWIRE) {
@@ -624,7 +633,7 @@ void AstNode::detectSignWidthWorker(int &width_hint, bool &sign_hint, bool *foun
 					// log("---\n");
 					// id_ast->dumpAst(NULL, "decl> ");
 					// dumpAst(NULL, "ref> ");
-					log_error("Failed to detect width of signal access `%s' at %s:%d!\n", str.c_str(), filename.c_str(), linenum);
+					log_file_error(filename, linenum, "Failed to detect width of signal access `%s'!\n", str.c_str());
 				}
 			} else {
 				this_width = id_ast->range_left - id_ast->range_right + 1;
@@ -635,10 +644,12 @@ void AstNode::detectSignWidthWorker(int &width_hint, bool &sign_hint, bool *foun
 			this_width = 32;
 		} else if (id_ast->type == AST_MEMORY) {
 			if (!id_ast->children[0]->range_valid)
-				log_error("Failed to detect width of memory access `%s' at %s:%d!\n", str.c_str(), filename.c_str(), linenum);
+				log_file_error(filename, linenum, "Failed to detect width of memory access `%s'!\n", str.c_str());
 			this_width = id_ast->children[0]->range_left - id_ast->children[0]->range_right + 1;
+			if (children.size() > 1)
+				range = children[1];
 		} else
-			log_error("Failed to detect width for identifier %s at %s:%d!\n", str.c_str(), filename.c_str(), linenum);
+			log_file_error(filename, linenum, "Failed to detect width for identifier %s!\n", str.c_str());
 		if (range) {
 			if (range->children.size() == 1)
 				this_width = 1;
@@ -648,9 +659,8 @@ void AstNode::detectSignWidthWorker(int &width_hint, bool &sign_hint, bool *foun
 				while (left_at_zero_ast->simplify(true, true, false, 1, -1, false, false)) { }
 				while (right_at_zero_ast->simplify(true, true, false, 1, -1, false, false)) { }
 				if (left_at_zero_ast->type != AST_CONSTANT || right_at_zero_ast->type != AST_CONSTANT)
-					log_error("Unsupported expression on dynamic range select on signal `%s' at %s:%d!\n",
-							str.c_str(), filename.c_str(), linenum);
-				this_width = left_at_zero_ast->integer - right_at_zero_ast->integer + 1;
+					log_file_error(filename, linenum, "Unsupported expression on dynamic range select on signal `%s'!\n", str.c_str());
+				this_width = abs(int(left_at_zero_ast->integer - right_at_zero_ast->integer)) + 1;
 				delete left_at_zero_ast;
 				delete right_at_zero_ast;
 			} else
@@ -665,7 +675,7 @@ void AstNode::detectSignWidthWorker(int &width_hint, bool &sign_hint, bool *foun
 	case AST_TO_BITS:
 		while (children[0]->simplify(true, false, false, 1, -1, false, false) == true) { }
 		if (children[0]->type != AST_CONSTANT)
-			log_error("Left operand of tobits expression is not constant at %s:%d!\n", filename.c_str(), linenum);
+			log_file_error(filename, linenum, "Left operand of tobits expression is not constant!\n");
 		children[1]->detectSignWidthWorker(sub_width_hint, sign_hint);
 		width_hint = max(width_hint, children[0]->bitsAsConst().as_int());
 		break;
@@ -693,7 +703,7 @@ void AstNode::detectSignWidthWorker(int &width_hint, bool &sign_hint, bool *foun
 	case AST_REPLICATE:
 		while (children[0]->simplify(true, false, false, 1, -1, false, true) == true) { }
 		if (children[0]->type != AST_CONSTANT)
-			log_error("Left operand of replicate expression is not constant at %s:%d!\n", filename.c_str(), linenum);
+			log_file_error(filename, linenum, "Left operand of replicate expression is not constant!\n");
 		children[1]->detectSignWidthWorker(sub_width_hint, sub_sign_hint);
 		width_hint = max(width_hint, children[0]->bitsAsConst().as_int() * sub_width_hint);
 		sign_hint = false;
@@ -767,7 +777,7 @@ void AstNode::detectSignWidthWorker(int &width_hint, bool &sign_hint, bool *foun
 		if (!id2ast->is_signed)
 			sign_hint = false;
 		if (!id2ast->children[0]->range_valid)
-			log_error("Failed to detect width of memory access `%s' at %s:%d!\n", str.c_str(), filename.c_str(), linenum);
+			log_file_error(filename, linenum, "Failed to detect width of memory access `%s'!\n", str.c_str());
 		this_width = id2ast->children[0]->range_left - id2ast->children[0]->range_right + 1;
 		width_hint = max(width_hint, this_width);
 		break;
@@ -777,8 +787,8 @@ void AstNode::detectSignWidthWorker(int &width_hint, bool &sign_hint, bool *foun
 			if (GetSize(children) == 1) {
 				while (children[0]->simplify(true, false, false, 1, -1, false, true) == true) { }
 				if (children[0]->type != AST_CONSTANT)
-					log_error("System function %s called with non-const argument at %s:%d!\n",
-							RTLIL::unescape_id(str).c_str(), filename.c_str(), linenum);
+					log_file_error(filename, linenum, "System function %s called with non-const argument!\n",
+							RTLIL::unescape_id(str).c_str());
 				width_hint = max(width_hint, int(children[0]->asInt(true)));
 			}
 			break;
@@ -798,9 +808,8 @@ void AstNode::detectSignWidthWorker(int &width_hint, bool &sign_hint, bool *foun
 	// everything should have been handled above -> print error if not.
 	default:
 		for (auto f : log_files)
-			current_ast->dumpAst(f, "verilog-ast> ");
-		log_error("Don't know how to detect sign and width for %s node at %s:%d!\n",
-				type2str(type).c_str(), filename.c_str(), linenum);
+			current_ast_mod->dumpAst(f, "verilog-ast> ");
+		log_file_error(filename, linenum, "Don't know how to detect sign and width for %s node!\n", type2str(type).c_str());
 	}
 
 	if (*found_real)
@@ -845,7 +854,6 @@ RTLIL::SigSpec AstNode::genRTLIL(int width_hint, bool sign_hint)
 	case AST_FUNCTION:
 	case AST_DPI_FUNCTION:
 	case AST_AUTOWIRE:
-	case AST_LOCALPARAM:
 	case AST_DEFPARAM:
 	case AST_GENVAR:
 	case AST_GENFOR:
@@ -853,23 +861,71 @@ RTLIL::SigSpec AstNode::genRTLIL(int width_hint, bool sign_hint)
 	case AST_GENIF:
 	case AST_GENCASE:
 	case AST_PACKAGE:
+	case AST_MODPORT:
+	case AST_MODPORTMEMBER:
+		break;
+	case AST_INTERFACEPORT: {
+		// If a port in a module with unknown type is found, mark it with the attribute 'is_interface'
+		// This is used by the hierarchy pass to know when it can replace interface connection with the individual
+		// signals.
+		RTLIL::Wire *wire = current_module->addWire(str, 1);
+		wire->attributes["\\src"] = stringf("%s:%d", filename.c_str(), linenum);
+		wire->start_offset = 0;
+		wire->port_id = port_id;
+		wire->port_input = true;
+		wire->port_output = true;
+		wire->set_bool_attribute("\\is_interface");
+		if (children.size() > 0) {
+			for(size_t i=0; i<children.size();i++) {
+				if(children[i]->type == AST_INTERFACEPORTTYPE) {
+					std::pair<std::string,std::string> res = AST::split_modport_from_type(children[i]->str);
+					wire->attributes["\\interface_type"] = res.first;
+					if (res.second != "")
+						wire->attributes["\\interface_modport"] = res.second;
+					break;
+				}
+			}
+		}
+		wire->upto = 0;
+		}
+		break;
+	case AST_INTERFACEPORTTYPE:
 		break;
 
 	// remember the parameter, needed for example in techmap
 	case AST_PARAMETER:
 		current_module->avail_parameters.insert(str);
+		/* fall through */
+	case AST_LOCALPARAM:
+		if (flag_pwires)
+		{
+			if (GetSize(children) < 1 || children[0]->type != AST_CONSTANT)
+				log_file_error(filename, linenum, "Parameter `%s' with non-constant value!\n", str.c_str());
+
+			RTLIL::Const val = children[0]->bitsAsConst();
+			RTLIL::Wire *wire = current_module->addWire(str, GetSize(val));
+			current_module->connect(wire, val);
+
+			wire->attributes["\\src"] = stringf("%s:%d", filename.c_str(), linenum);
+			wire->attributes[type == AST_PARAMETER ? "\\parameter" : "\\localparam"] = 1;
+
+			for (auto &attr : attributes) {
+				if (attr.second->type != AST_CONSTANT)
+					log_file_error(filename, linenum, "Attribute `%s' with non-constant value!\n", attr.first.c_str());
+				wire->attributes[attr.first] = attr.second->asAttrConst();
+			}
+		}
 		break;
 
 	// create an RTLIL::Wire for an AST_WIRE node
 	case AST_WIRE: {
 			if (current_module->wires_.count(str) != 0)
-				log_error("Re-definition of signal `%s' at %s:%d!\n",
-						str.c_str(), filename.c_str(), linenum);
+				log_file_error(filename, linenum, "Re-definition of signal `%s'!\n", str.c_str());
 			if (!range_valid)
-				log_error("Signal `%s' with non-constant width at %s:%d!\n",
-						str.c_str(), filename.c_str(), linenum);
+				log_file_error(filename, linenum, "Signal `%s' with non-constant width!\n", str.c_str());
 
-			log_assert(range_left >= range_right || (range_left == -1 && range_right == 0));
+			if (!(range_left >= range_right || (range_left == -1 && range_right == 0)))
+				log_file_error(filename, linenum, "Signal `%s' with invalid width range %d!\n", str.c_str(), range_left - range_right + 1);
 
 			RTLIL::Wire *wire = current_module->addWire(str, range_left - range_right + 1);
 			wire->attributes["\\src"] = stringf("%s:%d", filename.c_str(), linenum);
@@ -881,26 +937,26 @@ RTLIL::SigSpec AstNode::genRTLIL(int width_hint, bool sign_hint)
 
 			for (auto &attr : attributes) {
 				if (attr.second->type != AST_CONSTANT)
-					log_error("Attribute `%s' with non-constant value at %s:%d!\n",
-							attr.first.c_str(), filename.c_str(), linenum);
+					log_file_error(filename, linenum, "Attribute `%s' with non-constant value!\n", attr.first.c_str());
 				wire->attributes[attr.first] = attr.second->asAttrConst();
 			}
+
+			if (is_wand) wire->set_bool_attribute("\\wand");
+			if (is_wor)  wire->set_bool_attribute("\\wor");
 		}
 		break;
 
 	// create an RTLIL::Memory for an AST_MEMORY node
 	case AST_MEMORY: {
 			if (current_module->memories.count(str) != 0)
-				log_error("Re-definition of memory `%s' at %s:%d!\n",
-						str.c_str(), filename.c_str(), linenum);
+				log_file_error(filename, linenum, "Re-definition of memory `%s'!\n", str.c_str());
 
 			log_assert(children.size() >= 2);
 			log_assert(children[0]->type == AST_RANGE);
 			log_assert(children[1]->type == AST_RANGE);
 
 			if (!children[0]->range_valid || !children[1]->range_valid)
-				log_error("Memory `%s' with non-constant width or size at %s:%d!\n",
-						str.c_str(), filename.c_str(), linenum);
+				log_file_error(filename, linenum, "Memory `%s' with non-constant width or size!\n", str.c_str());
 
 			RTLIL::Memory *memory = new RTLIL::Memory;
 			memory->attributes["\\src"] = stringf("%s:%d", filename.c_str(), linenum);
@@ -917,8 +973,7 @@ RTLIL::SigSpec AstNode::genRTLIL(int width_hint, bool sign_hint)
 
 			for (auto &attr : attributes) {
 				if (attr.second->type != AST_CONSTANT)
-					log_error("Attribute `%s' with non-constant value at %s:%d!\n",
-							attr.first.c_str(), filename.c_str(), linenum);
+					log_file_error(filename, linenum, "Attribute `%s' with non-constant value!\n", attr.first.c_str());
 				memory->attributes[attr.first] = attr.second->asAttrConst();
 			}
 		}
@@ -926,19 +981,22 @@ RTLIL::SigSpec AstNode::genRTLIL(int width_hint, bool sign_hint)
 
 	// simply return the corresponding RTLIL::SigSpec for an AST_CONSTANT node
 	case AST_CONSTANT:
+	case AST_REALVALUE:
 		{
 			if (width_hint < 0)
 				detectSignWidth(width_hint, sign_hint);
-
 			is_signed = sign_hint;
-			return RTLIL::SigSpec(bitsAsConst());
-		}
 
-	case AST_REALVALUE:
-		{
+			if (type == AST_CONSTANT) {
+				if (is_unsized) {
+					return RTLIL::SigSpec(bitsAsUnsizedConst(width_hint));
+				} else {
+					return RTLIL::SigSpec(bitsAsConst());
+				}
+			}
+
 			RTLIL::SigSpec sig = realAsConst(width_hint);
-			log_warning("converting real value %e to binary %s at %s:%d.\n",
-					realvalue, log_signal(sig), filename.c_str(), linenum);
+			log_file_warning(filename, linenum, "converting real value %e to binary %s.\n", realvalue, log_signal(sig));
 			return sig;
 		}
 
@@ -949,6 +1007,7 @@ RTLIL::SigSpec AstNode::genRTLIL(int width_hint, bool sign_hint)
 		{
 			RTLIL::Wire *wire = NULL;
 			RTLIL::SigChunk chunk;
+			bool is_interface = false;
 
 			int add_undef_bits_msb = 0;
 			int add_undef_bits_lsb = 0;
@@ -958,25 +1017,48 @@ RTLIL::SigSpec AstNode::genRTLIL(int width_hint, bool sign_hint)
 				wire->attributes["\\src"] = stringf("%s:%d", filename.c_str(), linenum);
 				wire->name = str;
 				if (flag_autowire)
-					log_warning("Identifier `%s' is implicitly declared at %s:%d.\n", str.c_str(), filename.c_str(), linenum);
+					log_file_warning(filename, linenum, "Identifier `%s' is implicitly declared.\n", str.c_str());
 				else
-					log_error("Identifier `%s' is implicitly declared at %s:%d and `default_nettype is set to none.\n", str.c_str(), filename.c_str(), linenum);
+					log_file_error(filename, linenum, "Identifier `%s' is implicitly declared and `default_nettype is set to none.\n", str.c_str());
 			}
 			else if (id2ast->type == AST_PARAMETER || id2ast->type == AST_LOCALPARAM) {
 				if (id2ast->children[0]->type != AST_CONSTANT)
-					log_error("Parameter %s does not evaluate to constant value at %s:%d!\n",
-							str.c_str(), filename.c_str(), linenum);
+					log_file_error(filename, linenum, "Parameter %s does not evaluate to constant value!\n", str.c_str());
 				chunk = RTLIL::Const(id2ast->children[0]->bits);
 				goto use_const_chunk;
 			}
-			else if (!id2ast || (id2ast->type != AST_WIRE && id2ast->type != AST_AUTOWIRE &&
-					id2ast->type != AST_MEMORY) || current_module->wires_.count(str) == 0)
-				log_error("Identifier `%s' doesn't map to any signal at %s:%d!\n",
-						str.c_str(), filename.c_str(), linenum);
+			else if (id2ast && (id2ast->type == AST_WIRE || id2ast->type == AST_AUTOWIRE || id2ast->type == AST_MEMORY) && current_module->wires_.count(str) != 0) {
+				RTLIL::Wire *current_wire = current_module->wire(str);
+				if (current_wire->get_bool_attribute("\\is_interface"))
+					is_interface = true;
+				// Ignore
+			}
+			// If an identifier is found that is not already known, assume that it is an interface:
+			else if (1) { // FIXME: Check if sv_mode first?
+				is_interface = true;
+			}
+			else {
+				log_file_error(filename, linenum, "Identifier `%s' doesn't map to any signal!\n", str.c_str());
+			}
 
 			if (id2ast->type == AST_MEMORY)
-				log_error("Identifier `%s' does map to an unexpanded memory at %s:%d!\n",
-						str.c_str(), filename.c_str(), linenum);
+				log_file_error(filename, linenum, "Identifier `%s' does map to an unexpanded memory!\n", str.c_str());
+
+			// If identifier is an interface, create a RTLIL::SigSpec with a dummy wire with a attribute called 'is_interface'
+			// This makes it possible for the hierarchy pass to see what are interface connections and then replace them
+			// with the individual signals:
+			if (is_interface) {
+				RTLIL::Wire *dummy_wire;
+				std::string dummy_wire_name = "$dummywireforinterface" + str;
+				if (current_module->wires_.count(dummy_wire_name))
+					dummy_wire = current_module->wires_[dummy_wire_name];
+				else {
+					dummy_wire = current_module->addWire(dummy_wire_name);
+					dummy_wire->set_bool_attribute("\\is_interface");
+				}
+				RTLIL::SigSpec tmp = RTLIL::SigSpec(dummy_wire);
+				return tmp;
+			}
 
 			wire = current_module->wires_[str];
 			chunk.wire = wire;
@@ -985,7 +1067,8 @@ RTLIL::SigSpec AstNode::genRTLIL(int width_hint, bool sign_hint)
 
 		use_const_chunk:
 			if (children.size() != 0) {
-				log_assert(children[0]->type == AST_RANGE);
+				if (children[0]->type != AST_RANGE)
+					log_file_error(filename, linenum, "Single range expected.\n");
 				int source_width = id2ast->range_left - id2ast->range_right + 1;
 				int source_offset = id2ast->range_right;
 				if (!children[0]->range_valid) {
@@ -994,9 +1077,8 @@ RTLIL::SigSpec AstNode::genRTLIL(int width_hint, bool sign_hint)
 					while (left_at_zero_ast->simplify(true, true, false, 1, -1, false, false)) { }
 					while (right_at_zero_ast->simplify(true, true, false, 1, -1, false, false)) { }
 					if (left_at_zero_ast->type != AST_CONSTANT || right_at_zero_ast->type != AST_CONSTANT)
-						log_error("Unsupported expression on dynamic range select on signal `%s' at %s:%d!\n",
-								str.c_str(), filename.c_str(), linenum);
-					int width = left_at_zero_ast->integer - right_at_zero_ast->integer + 1;
+						log_file_error(filename, linenum, "Unsupported expression on dynamic range select on signal `%s'!\n", str.c_str());
+					int width = abs(int(left_at_zero_ast->integer - right_at_zero_ast->integer)) + 1;
 					AstNode *fake_ast = new AstNode(AST_NONE, clone(), children[0]->children.size() >= 2 ?
 							children[0]->children[1]->clone() : children[0]->children[0]->clone());
 					fake_ast->children[0]->delete_children();
@@ -1023,11 +1105,11 @@ RTLIL::SigSpec AstNode::genRTLIL(int width_hint, bool sign_hint)
 						chunk.offset = (id2ast->range_left - id2ast->range_right + 1) - (chunk.offset + chunk.width);
 					if (chunk.offset >= source_width || chunk.offset + chunk.width < 0) {
 						if (chunk.width == 1)
-							log_warning("Range select out of bounds on signal `%s' at %s:%d: Setting result bit to undef.\n",
-									str.c_str(), filename.c_str(), linenum);
+							log_file_warning(filename, linenum, "Range select out of bounds on signal `%s': Setting result bit to undef.\n",
+									str.c_str());
 						else
-							log_warning("Range select out of bounds on signal `%s' at %s:%d: Setting all %d result bits to undef.\n",
-									str.c_str(), filename.c_str(), linenum, chunk.width);
+							log_file_warning(filename, linenum, "Range select [%d:%d] out of bounds on signal `%s': Setting all %d result bits to undef.\n",
+									children[0]->range_left, children[0]->range_right, str.c_str(), chunk.width);
 						chunk = RTLIL::SigChunk(RTLIL::State::Sx, chunk.width);
 					} else {
 						if (chunk.width + chunk.offset > source_width) {
@@ -1040,11 +1122,11 @@ RTLIL::SigSpec AstNode::genRTLIL(int width_hint, bool sign_hint)
 							chunk.offset += add_undef_bits_lsb;
 						}
 						if (add_undef_bits_lsb)
-							log_warning("Range select out of bounds on signal `%s' at %s:%d: Setting %d LSB bits to undef.\n",
-									str.c_str(), filename.c_str(), linenum, add_undef_bits_lsb);
+							log_file_warning(filename, linenum, "Range [%d:%d] select out of bounds on signal `%s': Setting %d LSB bits to undef.\n",
+									children[0]->range_left, children[0]->range_right, str.c_str(), add_undef_bits_lsb);
 						if (add_undef_bits_msb)
-							log_warning("Range select out of bounds on signal `%s' at %s:%d: Setting %d MSB bits to undef.\n",
-									str.c_str(), filename.c_str(), linenum, add_undef_bits_msb);
+							log_file_warning(filename, linenum, "Range [%d:%d] select out of bounds on signal `%s': Setting %d MSB bits to undef.\n",
+									children[0]->range_left, children[0]->range_right, str.c_str(), add_undef_bits_msb);
 					}
 				}
 			}
@@ -1083,7 +1165,7 @@ RTLIL::SigSpec AstNode::genRTLIL(int width_hint, bool sign_hint)
 			RTLIL::SigSpec left = children[0]->genRTLIL();
 			RTLIL::SigSpec right = children[1]->genRTLIL();
 			if (!left.is_fully_const())
-				log_error("Left operand of replicate expression is not constant at %s:%d!\n", filename.c_str(), linenum);
+				log_file_error(filename, linenum, "Left operand of replicate expression is not constant!\n");
 			int count = left.as_int();
 			RTLIL::SigSpec sig;
 			for (int i = 0; i < count; i++)
@@ -1322,7 +1404,7 @@ RTLIL::SigSpec AstNode::genRTLIL(int width_hint, bool sign_hint)
 			int num_words = 1;
 			if (type == AST_MEMINIT) {
 				if (children[2]->type != AST_CONSTANT)
-					log_error("Memory init with non-constant word count at %s:%d!\n", filename.c_str(), linenum);
+					log_file_error(filename, linenum, "Memory init with non-constant word count!\n");
 				num_words = int(children[2]->asInt(false));
 				cell->parameters["\\WORDS"] = RTLIL::Const(num_words);
 			}
@@ -1371,16 +1453,21 @@ RTLIL::SigSpec AstNode::genRTLIL(int width_hint, bool sign_hint)
 			if (GetSize(en) != 1)
 				en = current_module->ReduceBool(NEW_ID, en);
 
-			std::stringstream sstr;
-			sstr << celltype << "$" << filename << ":" << linenum << "$" << (autoidx++);
+			IdString cellname;
+			if (str.empty()) {
+				std::stringstream sstr;
+				sstr << celltype << "$" << filename << ":" << linenum << "$" << (autoidx++);
+				cellname = sstr.str();
+			} else {
+				cellname = str;
+			}
 
-			RTLIL::Cell *cell = current_module->addCell(sstr.str(), celltype);
+			RTLIL::Cell *cell = current_module->addCell(cellname, celltype);
 			cell->attributes["\\src"] = stringf("%s:%d", filename.c_str(), linenum);
 
 			for (auto &attr : attributes) {
 				if (attr.second->type != AST_CONSTANT)
-					log_error("Attribute `%s' with non-constant value at %s:%d!\n",
-							attr.first.c_str(), filename.c_str(), linenum);
+					log_file_error(filename, linenum, "Attribute `%s' with non-constant value!\n", attr.first.c_str());
 				cell->attributes[attr.first] = attr.second->asAttrConst();
 			}
 
@@ -1401,9 +1488,9 @@ RTLIL::SigSpec AstNode::genRTLIL(int width_hint, bool sign_hint)
 						new_left.append(left[i]);
 						new_right.append(right[i]);
 					}
-				log_warning("Ignoring assignment to constant bits at %s:%d:\n"
+				log_file_warning(filename, linenum, "Ignoring assignment to constant bits:\n"
 						"    old assignment: %s = %s\n    new assignment: %s = %s.\n",
-						filename.c_str(), linenum, log_signal(left), log_signal(right),
+						log_signal(left), log_signal(right),
 						log_signal(new_left), log_signal(new_right));
 				left = new_left;
 				right = new_right;
@@ -1418,34 +1505,37 @@ RTLIL::SigSpec AstNode::genRTLIL(int width_hint, bool sign_hint)
 			int port_counter = 0, para_counter = 0;
 
 			if (current_module->count_id(str) != 0)
-				log_error("Re-definition of cell `%s' at %s:%d!\n",
-						str.c_str(), filename.c_str(), linenum);
+				log_file_error(filename, linenum, "Re-definition of cell `%s'!\n", str.c_str());
 
 			RTLIL::Cell *cell = current_module->addCell(str, "");
 			cell->attributes["\\src"] = stringf("%s:%d", filename.c_str(), linenum);
+			// Set attribute 'module_not_derived' which will be cleared again after the hierarchy pass
+			cell->set_bool_attribute("\\module_not_derived");
 
 			for (auto it = children.begin(); it != children.end(); it++) {
 				AstNode *child = *it;
 				if (child->type == AST_CELLTYPE) {
 					cell->type = child->str;
-					if (flag_icells && cell->type.substr(0, 2) == "\\$")
+					if (flag_icells && cell->type.begins_with("\\$"))
 						cell->type = cell->type.substr(1);
 					continue;
 				}
 				if (child->type == AST_PARASET) {
+					int extra_const_flags = 0;
 					IdString paraname = child->str.empty() ? stringf("$%d", ++para_counter) : child->str;
 					if (child->children[0]->type == AST_REALVALUE) {
-						log_warning("Replacing floating point parameter %s.%s = %f with string at %s:%d.\n",
-							log_id(cell), log_id(paraname), child->children[0]->realvalue,
-							filename.c_str(), linenum);
+						log_file_warning(filename, linenum, "Replacing floating point parameter %s.%s = %f with string.\n",
+								log_id(cell), log_id(paraname), child->children[0]->realvalue);
+						extra_const_flags = RTLIL::CONST_FLAG_REAL;
 						auto strnode = AstNode::mkconst_str(stringf("%f", child->children[0]->realvalue));
 						strnode->cloneInto(child->children[0]);
 						delete strnode;
 					}
 					if (child->children[0]->type != AST_CONSTANT)
-						log_error("Parameter %s.%s with non-constant value at %s:%d!\n",
-								log_id(cell), log_id(paraname), filename.c_str(), linenum);
+						log_file_error(filename, linenum, "Parameter %s.%s with non-constant value!\n",
+								log_id(cell), log_id(paraname));
 					cell->parameters[paraname] = child->children[0]->asParaConst();
+					cell->parameters[paraname].flags |= extra_const_flags;
 					continue;
 				}
 				if (child->type == AST_ARGUMENT) {
@@ -1465,10 +1555,29 @@ RTLIL::SigSpec AstNode::genRTLIL(int width_hint, bool sign_hint)
 			}
 			for (auto &attr : attributes) {
 				if (attr.second->type != AST_CONSTANT)
-					log_error("Attribute `%s' with non-constant value at %s:%d!\n",
-							attr.first.c_str(), filename.c_str(), linenum);
+					log_file_error(filename, linenum, "Attribute `%s' with non-constant value.\n", attr.first.c_str());
 				cell->attributes[attr.first] = attr.second->asAttrConst();
 			}
+			if (cell->type.in("$specify2", "$specify3")) {
+				int src_width = GetSize(cell->getPort("\\SRC"));
+				int dst_width = GetSize(cell->getPort("\\DST"));
+				bool full = cell->getParam("\\FULL").as_bool();
+				if (!full && src_width != dst_width)
+					log_file_error(filename, linenum, "Parallel specify SRC width does not match DST width.\n");
+				if (cell->type == "$specify3") {
+					int dat_width = GetSize(cell->getPort("\\DAT"));
+					if (dat_width != dst_width)
+						log_file_error(filename, linenum, "Specify DAT width does not match DST width.\n");
+				}
+				cell->setParam("\\SRC_WIDTH", Const(src_width));
+				cell->setParam("\\DST_WIDTH", Const(dst_width));
+			}
+			if (cell->type == "$specrule") {
+				int src_width = GetSize(cell->getPort("\\SRC"));
+				int dst_width = GetSize(cell->getPort("\\DST"));
+				cell->setParam("\\SRC_WIDTH", Const(src_width));
+				cell->setParam("\\DST_WIDTH", Const(dst_width));
+			}
 		}
 		break;
 
@@ -1486,6 +1595,37 @@ RTLIL::SigSpec AstNode::genRTLIL(int width_hint, bool sign_hint)
 			delete always;
 		} break;
 
+	case AST_TECALL: {
+			int sz = children.size();
+			if (str == "$info") {
+				if (sz > 0)
+					log_file_info(filename, linenum, "%s.\n", children[0]->str.c_str());
+				else
+					log_file_info(filename, linenum, "\n");
+			} else if (str == "$warning") {
+				if (sz > 0)
+					log_file_warning(filename, linenum, "%s.\n", children[0]->str.c_str());
+				else
+					log_file_warning(filename, linenum, "\n");
+			} else if (str == "$error") {
+				if (sz > 0)
+					log_file_error(filename, linenum, "%s.\n", children[0]->str.c_str());
+				else
+					log_file_error(filename, linenum, "\n");
+			} else if (str == "$fatal") {
+				// TODO: 1st parameter, if exists, is 0,1 or 2, and passed to $finish()
+				// if no parameter is given, default value is 1
+				// dollar_finish(sz ? children[0] : 1);
+				// perhaps create & use log_file_fatal()
+				if (sz > 0)
+					log_file_error(filename, linenum, "FATAL: %s.\n", children[0]->str.c_str());
+				else
+					log_file_error(filename, linenum, "FATAL.\n");
+			} else {
+				log_file_error(filename, linenum, "Unknown elabortoon system task '%s'.\n", str.c_str());
+			}
+		} break;
+
 	case AST_FCALL: {
 			if (str == "\\$anyconst" || str == "\\$anyseq" || str == "\\$allconst" || str == "\\$allseq")
 			{
@@ -1493,19 +1633,18 @@ RTLIL::SigSpec AstNode::genRTLIL(int width_hint, bool sign_hint)
 				int width = width_hint;
 
 				if (GetSize(children) > 1)
-					log_error("System function %s got %d arguments, expected 1 or 0 at %s:%d.\n",
-							RTLIL::unescape_id(str).c_str(), GetSize(children), filename.c_str(), linenum);
+					log_file_error(filename, linenum, "System function %s got %d arguments, expected 1 or 0.\n",
+							RTLIL::unescape_id(str).c_str(), GetSize(children));
 
 				if (GetSize(children) == 1) {
 					if (children[0]->type != AST_CONSTANT)
-						log_error("System function %s called with non-const argument at %s:%d!\n",
-								RTLIL::unescape_id(str).c_str(), filename.c_str(), linenum);
+						log_file_error(filename, linenum, "System function %s called with non-const argument!\n",
+								RTLIL::unescape_id(str).c_str());
 					width = children[0]->asInt(true);
 				}
 
 				if (width <= 0)
-					log_error("Failed to detect width of %s at %s:%d!\n",
-							RTLIL::unescape_id(str).c_str(), filename.c_str(), linenum);
+					log_file_error(filename, linenum, "Failed to detect width of %s!\n", RTLIL::unescape_id(str).c_str());
 
 				Cell *cell = current_module->addCell(myid, str.substr(1));
 				cell->attributes["\\src"] = stringf("%s:%d", filename.c_str(), linenum);
@@ -1514,7 +1653,7 @@ RTLIL::SigSpec AstNode::genRTLIL(int width_hint, bool sign_hint)
 				if (attributes.count("\\reg")) {
 					auto &attr = attributes.at("\\reg");
 					if (attr->type != AST_CONSTANT)
-						log_error("Attribute `reg' with non-constant value at %s:%d!\n", filename.c_str(), linenum);
+						log_file_error(filename, linenum, "Attribute `reg' with non-constant value!\n");
 					cell->attributes["\\reg"] =  attr->asAttrConst();
 				}
 
@@ -1530,10 +1669,9 @@ RTLIL::SigSpec AstNode::genRTLIL(int width_hint, bool sign_hint)
 	// everything should have been handled above -> print error if not.
 	default:
 		for (auto f : log_files)
-			current_ast->dumpAst(f, "verilog-ast> ");
+			current_ast_mod->dumpAst(f, "verilog-ast> ");
 		type_name = type2str(type);
-		log_error("Don't know how to generate RTLIL code for %s node at %s:%d!\n",
-				type_name.c_str(), filename.c_str(), linenum);
+		log_file_error(filename, linenum, "Don't know how to generate RTLIL code for %s node!\n", type_name.c_str());
 	}
 
 	return RTLIL::SigSpec();
@@ -1563,4 +1701,3 @@ RTLIL::SigSpec AstNode::genWidthRTLIL(int width, const dict<RTLIL::SigBit, RTLIL
 }
 
 YOSYS_NAMESPACE_END
-
diff --git a/frontends/ast/simplify.cc b/frontends/ast/simplify.cc
index a16fdfeeb..b1ee22f42 100644
--- a/frontends/ast/simplify.cc
+++ b/frontends/ast/simplify.cc
@@ -50,7 +50,6 @@ using namespace AST_INTERNAL;
 bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage, int width_hint, bool sign_hint, bool in_param)
 {
 	static int recursion_counter = 0;
-	static pair<string, int> last_blocking_assignment_warn;
 	static bool deep_recursion_warning = false;
 
 	if (recursion_counter++ == 1000 && deep_recursion_warning) {
@@ -71,8 +70,7 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 
 	if (stage == 0)
 	{
-		log_assert(type == AST_MODULE);
-		last_blocking_assignment_warn = pair<string, int>();
+		log_assert(type == AST_MODULE || type == AST_INTERFACE);
 
 		deep_recursion_warning = true;
 		while (simplify(const_fold, at_zero, in_lvalue, 1, width_hint, sign_hint, in_param)) { }
@@ -113,6 +111,9 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 				if (memflags & AstNode::MEM2REG_FL_CMPLX_LHS)
 					goto verbose_activate;
 
+				if ((memflags & AstNode::MEM2REG_FL_CONST_LHS) && !(memflags & AstNode::MEM2REG_FL_VAR_LHS))
+					goto verbose_activate;
+
 				// log("Note: Not replacing memory %s with list of registers (flags=0x%08lx).\n", mem->str.c_str(), long(memflags));
 				continue;
 
@@ -137,12 +138,23 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 				int mem_width, mem_size, addr_bits;
 				node->meminfo(mem_width, mem_size, addr_bits);
 
+				int data_range_left = node->children[0]->range_left;
+				int data_range_right = node->children[0]->range_right;
+
+				if (node->children[0]->range_swapped)
+					std::swap(data_range_left, data_range_right);
+
 				for (int i = 0; i < mem_size; i++) {
 					AstNode *reg = new AstNode(AST_WIRE, new AstNode(AST_RANGE,
-							mkconst_int(mem_width-1, true), mkconst_int(0, true)));
+							mkconst_int(data_range_left, true), mkconst_int(data_range_right, true)));
 					reg->str = stringf("%s[%d]", node->str.c_str(), i);
 					reg->is_reg = true;
 					reg->is_signed = node->is_signed;
+					for (auto &it : node->attributes)
+						if (it.first != ID(mem2reg))
+							reg->attributes.emplace(it.first, it.second->clone());
+					reg->filename = node->filename;
+					reg->linenum = node->linenum;
 					children.push_back(reg);
 					while (reg->simplify(true, false, false, 1, -1, false, false)) { }
 				}
@@ -177,13 +189,13 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 	// note that $display, $finish, and $stop are used for synthesis-time DRC so they're not in this list
 	if ((type == AST_FCALL || type == AST_TCALL) && (str == "$strobe" || str == "$monitor" || str == "$time" ||
 			str == "$dumpfile" || str == "$dumpvars" || str == "$dumpon" || str == "$dumpoff" || str == "$dumpall")) {
-		log_warning("Ignoring call to system %s %s at %s:%d.\n", type == AST_FCALL ? "function" : "task", str.c_str(), filename.c_str(), linenum);
+		log_file_warning(filename, linenum, "Ignoring call to system %s %s.\n", type == AST_FCALL ? "function" : "task", str.c_str());
 		delete_children();
 		str = std::string();
 	}
 
 	if ((type == AST_TCALL) && (str == "$display" || str == "$write") && (!current_always || current_always->type != AST_INITIAL)) {
-		log_warning("System task `%s' outside initial block is unsupported at %s:%d.\n", str.c_str(), filename.c_str(), linenum);
+		log_file_warning(filename, linenum, "System task `%s' outside initial block is unsupported.\n", str.c_str());
 		delete_children();
 		str = std::string();
 	}
@@ -195,14 +207,14 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 	{
 		int nargs = GetSize(children);
 		if (nargs < 1)
-			log_error("System task `%s' got %d arguments, expected >= 1 at %s:%d.\n",
-					str.c_str(), int(children.size()), filename.c_str(), linenum);
+			log_file_error(filename, linenum, "System task `%s' got %d arguments, expected >= 1.\n",
+					str.c_str(), int(children.size()));
 
 		// First argument is the format string
 		AstNode *node_string = children[0];
 		while (node_string->simplify(true, false, false, stage, width_hint, sign_hint, false)) { }
 		if (node_string->type != AST_CONSTANT)
-			log_error("Failed to evaluate system task `%s' with non-constant 1st argument at %s:%d.\n", str.c_str(), filename.c_str(), linenum);
+			log_file_error(filename, linenum, "Failed to evaluate system task `%s' with non-constant 1st argument.\n", str.c_str());
 		std::string sformat = node_string->bitsAsConst().decode_string();
 
 		// Other arguments are placeholders. Process the string as we go through it
@@ -215,7 +227,7 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 			{
 				// If there's no next character, that's a problem
 				if (i+1 >= sformat.length())
-					log_error("System task `%s' called with `%%' at end of string at %s:%d.\n", str.c_str(), filename.c_str(), linenum);
+					log_file_error(filename, linenum, "System task `%s' called with `%%' at end of string.\n", str.c_str());
 
 				char cformat = sformat[++i];
 
@@ -239,13 +251,13 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 					case 'x':
 					case 'X':
 						if (next_arg >= GetSize(children))
-							log_error("Missing argument for %%%c format specifier in system task `%s' at %s:%d.\n",
-									cformat, str.c_str(), filename.c_str(), linenum);
+							log_file_error(filename, linenum, "Missing argument for %%%c format specifier in system task `%s'.\n",
+									cformat, str.c_str());
 
 						node_arg = children[next_arg++];
 						while (node_arg->simplify(true, false, false, stage, width_hint, sign_hint, false)) { }
 						if (node_arg->type != AST_CONSTANT)
-							log_error("Failed to evaluate system task `%s' with non-constant argument at %s:%d.\n", str.c_str(), filename.c_str(), linenum);
+							log_file_error(filename, linenum, "Failed to evaluate system task `%s' with non-constant argument.\n", str.c_str());
 						break;
 
 					case 'm':
@@ -253,7 +265,7 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 						break;
 
 					default:
-						log_error("System task `%s' called with invalid/unsupported format specifier at %s:%d.\n", str.c_str(), filename.c_str(), linenum);
+						log_file_error(filename, linenum, "System task `%s' called with invalid/unsupported format specifier.\n", str.c_str());
 						break;
 				}
 
@@ -325,8 +337,19 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 		for (size_t i = 0; i < children.size(); i++) {
 			AstNode *node = children[i];
 			if (node->type == AST_WIRE) {
+				if (node->children.size() == 1 && node->children[0]->type == AST_RANGE) {
+					for (auto c : node->children[0]->children) {
+						if (!c->is_simple_const_expr()) {
+							if (attributes.count("\\dynports"))
+								delete attributes.at("\\dynports");
+							attributes["\\dynports"] = AstNode::mkconst_int(1, true);
+						}
+					}
+				}
 				if (this_wire_scope.count(node->str) > 0) {
 					AstNode *first_node = this_wire_scope[node->str];
+					if (first_node->is_input && node->is_reg)
+						goto wires_are_incompatible;
 					if (!node->is_input && !node->is_output && node->is_reg && node->children.size() == 0)
 						goto wires_are_compatible;
 					if (first_node->children.size() == 0 && node->children.size() == 1 && node->children[0]->type == AST_RANGE) {
@@ -361,6 +384,8 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 						first_node->is_output = true;
 					if (node->is_reg)
 						first_node->is_reg = true;
+					if (node->is_logic)
+						first_node->is_logic = true;
 					if (node->is_signed)
 						first_node->is_signed = true;
 					for (auto &it : node->attributes) {
@@ -374,7 +399,7 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 					continue;
 				wires_are_incompatible:
 					if (stage > 1)
-						log_error("Incompatible re-declaration of wire %s at %s:%d.\n", node->str.c_str(), filename.c_str(), linenum);
+						log_file_error(filename, linenum, "Incompatible re-declaration of wire %s.\n", node->str.c_str());
 					continue;
 				}
 				this_wire_scope[node->str] = node;
@@ -402,7 +427,7 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 	if (type == AST_ALWAYS || type == AST_INITIAL)
 	{
 		if (current_always != nullptr)
-			log_error("Invalid nesting of always blocks and/or initializations at %s:%d.\n", filename.c_str(), linenum);
+			log_file_error(filename, linenum, "Invalid nesting of always blocks and/or initializations.\n");
 
 		current_always = this;
 		current_always_clocked = false;
@@ -440,6 +465,29 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 		children[1]->detectSignWidth(width_hint, sign_hint);
 		width_hint = max(width_hint, backup_width_hint);
 		child_0_is_self_determined = true;
+		// test only once, before optimizations and memory mappings but after assignment LHS was mapped to an identifier
+		if (children[0]->id2ast && !children[0]->was_checked) {
+			if ((type == AST_ASSIGN_LE || type == AST_ASSIGN_EQ) && children[0]->id2ast->is_logic)
+				children[0]->id2ast->is_reg = true; // if logic type is used in a block asignment
+			if ((type == AST_ASSIGN_LE || type == AST_ASSIGN_EQ) && !children[0]->id2ast->is_reg)
+				log_warning("wire '%s' is assigned in a block at %s:%d.\n", children[0]->str.c_str(), filename.c_str(), linenum);
+			if (type == AST_ASSIGN && children[0]->id2ast->is_reg) {
+				bool is_rand_reg = false;
+				if (children[1]->type == AST_FCALL) {
+					if (children[1]->str == "\\$anyconst")
+						is_rand_reg = true;
+					if (children[1]->str == "\\$anyseq")
+						is_rand_reg = true;
+					if (children[1]->str == "\\$allconst")
+						is_rand_reg = true;
+					if (children[1]->str == "\\$allseq")
+						is_rand_reg = true;
+				}
+				if (!is_rand_reg)
+					log_warning("reg '%s' is assigned in a continuous assignment at %s:%d.\n", children[0]->str.c_str(), filename.c_str(), linenum);
+			}
+			children[0]->was_checked = true;
+		}
 		break;
 
 	case AST_PARAMETER:
@@ -451,7 +499,7 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 			while (!children[1]->basic_prep && children[1]->simplify(false, false, false, stage, -1, false, true) == true)
 				did_something = true;
 			if (!children[1]->range_valid)
-				log_error("Non-constant width range on parameter decl at %s:%d.\n", filename.c_str(), linenum);
+				log_file_error(filename, linenum, "Non-constant width range on parameter decl.\n");
 			width_hint = max(width_hint, children[1]->range_left - children[1]->range_right + 1);
 		}
 		break;
@@ -615,6 +663,7 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 	// (iterate by index as e.g. auto wires can add new children in the process)
 	for (size_t i = 0; i < children.size(); i++) {
 		bool did_something_here = true;
+		bool backup_flag_autowire = flag_autowire;
 		if ((type == AST_GENFOR || type == AST_FOR) && i >= 3)
 			break;
 		if ((type == AST_GENIF || type == AST_GENCASE) && i >= 1)
@@ -625,6 +674,8 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 			break;
 		if (type == AST_PREFIX && i >= 1)
 			break;
+		if (type == AST_DEFPARAM && i == 0)
+			flag_autowire = true;
 		while (did_something_here && i < children.size()) {
 			bool const_fold_here = const_fold, in_lvalue_here = in_lvalue;
 			int width_hint_here = width_hint;
@@ -659,6 +710,7 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 			children.erase(children.begin() + (i--));
 			did_something = true;
 		}
+		flag_autowire = backup_flag_autowire;
 	}
 	for (auto &attr : attributes) {
 		while (attr.second->simplify(true, false, false, stage, -1, false, true))
@@ -695,7 +747,7 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 	if (type == AST_DEFPARAM && !children.empty())
 	{
 		if (children[0]->type != AST_IDENTIFIER)
-			log_error("Module name in defparam at %s:%d contains non-constant expressions!\n", filename.c_str(), linenum);
+			log_file_error(filename, linenum, "Module name in defparam contains non-constant expressions!\n");
 
 		string modname, paramname = children[0]->str;
 
@@ -712,13 +764,13 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 		}
 
 		if (pos == std::string::npos)
-			log_error("Can't find object for defparam `%s` at %s:%d!\n", RTLIL::unescape_id(paramname).c_str(), filename.c_str(), linenum);
+			log_file_error(filename, linenum, "Can't find object for defparam `%s`!\n", RTLIL::unescape_id(paramname).c_str());
 
 		paramname = "\\" + paramname.substr(pos+1);
 
 		if (current_scope.at(modname)->type != AST_CELL)
-			log_error("Defparam argument `%s . %s` does not match a cell at %s:%d!\n",
-					RTLIL::unescape_id(modname).c_str(), RTLIL::unescape_id(paramname).c_str(), filename.c_str(), linenum);
+			log_file_error(filename, linenum, "Defparam argument `%s . %s` does not match a cell!\n",
+					RTLIL::unescape_id(modname).c_str(), RTLIL::unescape_id(paramname).c_str());
 
 		AstNode *paraset = new AstNode(AST_PARASET, children[1]->clone(), GetSize(children) > 2 ? children[2]->clone() : NULL);
 		paraset->str = paramname;
@@ -732,7 +784,7 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 	if (type == AST_PREFIX) {
 		if (children[0]->type != AST_CONSTANT) {
 			// dumpAst(NULL, ">   ");
-			log_error("Index in generate block prefix syntax at %s:%d is not constant!\n", filename.c_str(), linenum);
+			log_file_error(filename, linenum, "Index in generate block prefix syntax is not constant!\n");
 		}
 		if (children[1]->type == AST_PREFIX)
 			children[1]->simplify(const_fold, at_zero, in_lvalue, stage, width_hint, sign_hint, in_param);
@@ -748,9 +800,9 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 	// evaluate TO_BITS nodes
 	if (type == AST_TO_BITS) {
 		if (children[0]->type != AST_CONSTANT)
-			log_error("Left operand of to_bits expression is not constant at %s:%d!\n", filename.c_str(), linenum);
+			log_file_error(filename, linenum, "Left operand of to_bits expression is not constant!\n");
 		if (children[1]->type != AST_CONSTANT)
-			log_error("Right operand of to_bits expression is not constant at %s:%d!\n", filename.c_str(), linenum);
+			log_file_error(filename, linenum, "Right operand of to_bits expression is not constant!\n");
 		RTLIL::Const new_value = children[1]->bitsAsConst(children[0]->bitsAsConst().as_int(), children[1]->is_signed);
 		newNode = mkconst_bits(new_value.bits, children[1]->is_signed);
 		goto apply_newNode;
@@ -814,7 +866,7 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 		multirange_dimensions.clear();
 		for (auto range : children[1]->children) {
 			if (!range->range_valid)
-				log_error("Non-constant range on memory decl at %s:%d.\n", filename.c_str(), linenum);
+				log_file_error(filename, linenum, "Non-constant range on memory decl.\n");
 			multirange_dimensions.push_back(min(range->range_left, range->range_right));
 			multirange_dimensions.push_back(max(range->range_left, range->range_right) - min(range->range_left, range->range_right) + 1);
 			total_size *= multirange_dimensions.back();
@@ -832,7 +884,7 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 		for (int i = 0; 2*i < GetSize(id2ast->multirange_dimensions); i++)
 		{
 			if (GetSize(children[0]->children) < i)
-				log_error("Insufficient number of array indices for %s at %s:%d.\n", log_id(str), filename.c_str(), linenum);
+				log_file_error(filename, linenum, "Insufficient number of array indices for %s.\n", log_id(str));
 
 			AstNode *new_index_expr = children[0]->children[i]->children.at(0)->clone();
 
@@ -861,12 +913,12 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 	if (type == AST_PARAMETER || type == AST_LOCALPARAM) {
 		if (children.size() > 1 && children[1]->type == AST_RANGE) {
 			if (!children[1]->range_valid)
-				log_error("Non-constant width range on parameter decl at %s:%d.\n", filename.c_str(), linenum);
+				log_file_error(filename, linenum, "Non-constant width range on parameter decl.\n");
 			int width = std::abs(children[1]->range_left - children[1]->range_right) + 1;
 			if (children[0]->type == AST_REALVALUE) {
 				RTLIL::Const constvalue = children[0]->realAsConst(width);
-				log_warning("converting real value %e to binary %s at %s:%d.\n",
-						children[0]->realvalue, log_signal(constvalue), filename.c_str(), linenum);
+				log_file_warning(filename, linenum, "converting real value %e to binary %s.\n",
+						children[0]->realvalue, log_signal(constvalue));
 				delete children[0];
 				children[0] = mkconst_bits(constvalue.bits, sign_hint);
 				did_something = true;
@@ -907,12 +959,15 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 			}
 		}
 		if (current_scope.count(str) == 0) {
-			// log_warning("Creating auto-wire `%s' in module `%s'.\n", str.c_str(), current_ast_mod->str.c_str());
-			AstNode *auto_wire = new AstNode(AST_AUTOWIRE);
-			auto_wire->str = str;
-			current_ast_mod->children.push_back(auto_wire);
-			current_scope[str] = auto_wire;
-			did_something = true;
+			if (flag_autowire || str == "\\$global_clock") {
+				AstNode *auto_wire = new AstNode(AST_AUTOWIRE);
+				auto_wire->str = str;
+				current_ast_mod->children.push_back(auto_wire);
+				current_scope[str] = auto_wire;
+				did_something = true;
+			} else {
+				log_file_error(filename, linenum, "Identifier `%s' is implicitly declared and `default_nettype is set to none.\n", str.c_str());
+			}
 		}
 		if (id2ast != current_scope[str]) {
 			id2ast = current_scope[str];
@@ -924,7 +979,7 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 	if (type == AST_IDENTIFIER && children.size() == 2 && children[0]->type == AST_RANGE && children[1]->type == AST_RANGE && !in_lvalue)
 	{
 		if (id2ast == NULL || id2ast->type != AST_MEMORY || children[0]->children.size() != 1)
-			log_error("Invalid bit-select on memory access at %s:%d!\n", filename.c_str(), linenum);
+			log_file_error(filename, linenum, "Invalid bit-select on memory access!\n");
 
 		int mem_width, mem_size, addr_bits;
 		id2ast->meminfo(mem_width, mem_size, addr_bits);
@@ -932,6 +987,9 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 		int data_range_left = id2ast->children[0]->range_left;
 		int data_range_right = id2ast->children[0]->range_right;
 
+		if (id2ast->children[0]->range_swapped)
+			std::swap(data_range_left, data_range_right);
+
 		std::stringstream sstr;
 		sstr << "$mem2bits$" << str << "$" << filename << ":" << linenum << "$" << (autoidx++);
 		std::string wire_id = sstr.str();
@@ -949,6 +1007,7 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 
 		AstNode *assign = new AstNode(AST_ASSIGN_EQ, new AstNode(AST_IDENTIFIER), data);
 		assign->children[0]->str = wire_id;
+		assign->children[0]->was_checked = true;
 
 		if (current_block)
 		{
@@ -973,10 +1032,29 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 	}
 
 	if (type == AST_WHILE)
-		log_error("While loops are only allowed in constant functions at %s:%d!\n", filename.c_str(), linenum);
+		log_file_error(filename, linenum, "While loops are only allowed in constant functions!\n");
 
 	if (type == AST_REPEAT)
-		log_error("Repeat loops are only allowed in constant functions at %s:%d!\n", filename.c_str(), linenum);
+	{
+		AstNode *count = children[0];
+		AstNode *body = children[1];
+
+		// eval count expression
+		while (count->simplify(true, false, false, stage, 32, true, false)) { }
+
+		if (count->type != AST_CONSTANT)
+			log_file_error(filename, linenum, "Repeat loops outside must have constant repeat counts!\n");
+
+		// convert to a block with the body repeated n times
+		type = AST_BLOCK;
+		children.clear();
+		for (int i = 0; i < count->bitsAsConst().as_int(); i++)
+			children.insert(children.begin(), body->clone());
+
+		delete count;
+		delete body;
+		did_something = true;
+	}
 
 	// unroll for loops and generate-for blocks
 	if ((type == AST_GENFOR || type == AST_FOR) && children.size() != 0)
@@ -991,31 +1069,36 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 			body_ast = body_ast->children.at(0);
 
 		if (init_ast->type != AST_ASSIGN_EQ)
-			log_error("Unsupported 1st expression of generate for-loop at %s:%d!\n", filename.c_str(), linenum);
+			log_file_error(filename, linenum, "Unsupported 1st expression of generate for-loop!\n");
 		if (next_ast->type != AST_ASSIGN_EQ)
-			log_error("Unsupported 3rd expression of generate for-loop at %s:%d!\n", filename.c_str(), linenum);
+			log_file_error(filename, linenum, "Unsupported 3rd expression of generate for-loop!\n");
 
 		if (type == AST_GENFOR) {
 			if (init_ast->children[0]->id2ast == NULL || init_ast->children[0]->id2ast->type != AST_GENVAR)
-				log_error("Left hand side of 1st expression of generate for-loop at %s:%d is not a gen var!\n", filename.c_str(), linenum);
+				log_file_error(filename, linenum, "Left hand side of 1st expression of generate for-loop is not a gen var!\n");
 			if (next_ast->children[0]->id2ast == NULL || next_ast->children[0]->id2ast->type != AST_GENVAR)
-				log_error("Left hand side of 3rd expression of generate for-loop at %s:%d is not a gen var!\n", filename.c_str(), linenum);
+				log_file_error(filename, linenum, "Left hand side of 3rd expression of generate for-loop is not a gen var!\n");
 		} else {
 			if (init_ast->children[0]->id2ast == NULL || init_ast->children[0]->id2ast->type != AST_WIRE)
-				log_error("Left hand side of 1st expression of generate for-loop at %s:%d is not a register!\n", filename.c_str(), linenum);
+				log_file_error(filename, linenum, "Left hand side of 1st expression of generate for-loop is not a register!\n");
 			if (next_ast->children[0]->id2ast == NULL || next_ast->children[0]->id2ast->type != AST_WIRE)
-				log_error("Left hand side of 3rd expression of generate for-loop at %s:%d is not a register!\n", filename.c_str(), linenum);
+				log_file_error(filename, linenum, "Left hand side of 3rd expression of generate for-loop is not a register!\n");
 		}
 
 		if (init_ast->children[0]->id2ast != next_ast->children[0]->id2ast)
-			log_error("Incompatible left-hand sides in 1st and 3rd expression of generate for-loop at %s:%d!\n", filename.c_str(), linenum);
+			log_file_error(filename, linenum, "Incompatible left-hand sides in 1st and 3rd expression of generate for-loop!\n");
 
 		// eval 1st expression
 		AstNode *varbuf = init_ast->children[1]->clone();
-		while (varbuf->simplify(true, false, false, stage, 32, true, false)) { }
+		{
+			int expr_width_hint = -1;
+			bool expr_sign_hint = true;
+			varbuf->detectSignWidth(expr_width_hint, expr_sign_hint);
+			while (varbuf->simplify(true, false, false, stage, 32, true, false)) { }
+		}
 
 		if (varbuf->type != AST_CONSTANT)
-			log_error("Right hand side of 1st expression of generate for-loop at %s:%d is not constant!\n", filename.c_str(), linenum);
+			log_file_error(filename, linenum, "Right hand side of 1st expression of generate for-loop is not constant!\n");
 
 		varbuf = new AstNode(AST_LOCALPARAM, varbuf);
 		varbuf->str = init_ast->children[0]->str;
@@ -1034,10 +1117,15 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 		{
 			// eval 2nd expression
 			AstNode *buf = while_ast->clone();
-			while (buf->simplify(true, false, false, stage, width_hint, sign_hint, false)) { }
+			{
+				int expr_width_hint = -1;
+				bool expr_sign_hint = true;
+				buf->detectSignWidth(expr_width_hint, expr_sign_hint);
+				while (buf->simplify(true, false, false, stage, expr_width_hint, expr_sign_hint, false)) { }
+			}
 
 			if (buf->type != AST_CONSTANT)
-				log_error("2nd expression of generate for-loop at %s:%d is not constant!\n", filename.c_str(), linenum);
+				log_file_error(filename, linenum, "2nd expression of generate for-loop is not constant!\n");
 
 			if (buf->integer == 0) {
 				delete buf;
@@ -1075,15 +1163,27 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 
 			// eval 3rd expression
 			buf = next_ast->children[1]->clone();
-			while (buf->simplify(true, false, false, stage, 32, true, false)) { }
+			{
+				int expr_width_hint = -1;
+				bool expr_sign_hint = true;
+				buf->detectSignWidth(expr_width_hint, expr_sign_hint);
+				while (buf->simplify(true, false, false, stage, expr_width_hint, expr_sign_hint, true)) { }
+			}
 
 			if (buf->type != AST_CONSTANT)
-				log_error("Right hand side of 3rd expression of generate for-loop at %s:%d is not constant!\n", filename.c_str(), linenum);
+				log_file_error(filename, linenum, "Right hand side of 3rd expression of generate for-loop is not constant!\n");
 
 			delete varbuf->children[0];
 			varbuf->children[0] = buf;
 		}
 
+		if (type == AST_FOR) {
+			AstNode *buf = next_ast->clone();
+			delete buf->children[1];
+			buf->children[1] = varbuf->children[0]->clone();
+			current_block->children.insert(current_block->children.begin() + current_block_idx++, buf);
+		}
+
 		current_scope[varbuf->str] = backup_scope_varbuf;
 		delete varbuf;
 		delete_children();
@@ -1095,8 +1195,7 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 	{
 		for (size_t i = 0; i < children.size(); i++)
 			if (children[i]->type == AST_WIRE || children[i]->type == AST_MEMORY || children[i]->type == AST_PARAMETER || children[i]->type == AST_LOCALPARAM)
-				log_error("Local declaration in unnamed block at %s:%d is an unsupported SystemVerilog feature!\n",
-						children[i]->filename.c_str(), children[i]->linenum);
+				log_file_error(children[i]->filename, children[i]->linenum, "Local declaration in unnamed block is an unsupported SystemVerilog feature!\n");
 	}
 
 	// transform block with name
@@ -1144,7 +1243,7 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 		if (buf->type != AST_CONSTANT) {
 			// for (auto f : log_files)
 			// 	dumpAst(f, "verilog-ast> ");
-			log_error("Condition for generate if at %s:%d is not constant!\n", filename.c_str(), linenum);
+			log_file_error(filename, linenum, "Condition for generate if is not constant!\n");
 		}
 		if (buf->asBool() != 0) {
 			delete buf;
@@ -1185,7 +1284,7 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 		if (buf->type != AST_CONSTANT) {
 			// for (auto f : log_files)
 			// 	dumpAst(f, "verilog-ast> ");
-			log_error("Condition for generate case at %s:%d is not constant!\n", filename.c_str(), linenum);
+			log_file_error(filename, linenum, "Condition for generate case is not constant!\n");
 		}
 
 		bool ref_signed = buf->is_signed;
@@ -1219,7 +1318,7 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 				if (buf->type != AST_CONSTANT) {
 					// for (auto f : log_files)
 					// 	dumpAst(f, "verilog-ast> ");
-					log_error("Expression in generate case at %s:%d is not constant!\n", filename.c_str(), linenum);
+					log_file_error(filename, linenum, "Expression in generate case is not constant!\n");
 				}
 
 				bool is_selected = RTLIL::const_eq(ref_value, buf->bitsAsConst(), ref_signed && buf->is_signed, ref_signed && buf->is_signed, 1).as_bool();
@@ -1260,7 +1359,7 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 	if (type == AST_CELLARRAY)
 	{
 		if (!children.at(0)->range_valid)
-			log_error("Non-constant array range on cell array at %s:%d.\n", filename.c_str(), linenum);
+			log_file_error(filename, linenum, "Non-constant array range on cell array.\n");
 
 		newNode = new AstNode(AST_GENBLOCK);
 		int num = max(children.at(0)->range_left, children.at(0)->range_right) - min(children.at(0)->range_left, children.at(0)->range_right) + 1;
@@ -1271,7 +1370,7 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 			newNode->children.push_back(new_cell);
 			new_cell->str += stringf("[%d]", idx);
 			if (new_cell->type == AST_PRIMITIVE) {
-				log_error("Cell arrays of primitives are currently not supported at %s:%d.\n", filename.c_str(), linenum);
+				log_file_error(filename, linenum, "Cell arrays of primitives are currently not supported.\n");
 			} else {
 				log_assert(new_cell->children.at(0)->type == AST_CELLTYPE);
 				new_cell->children.at(0)->str = stringf("$array:%d:%d:%s", i, num, new_cell->children.at(0)->str.c_str());
@@ -1285,8 +1384,7 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 	if (type == AST_PRIMITIVE)
 	{
 		if (children.size() < 2)
-			log_error("Insufficient number of arguments for primitive `%s' at %s:%d!\n",
-					str.c_str(), filename.c_str(), linenum);
+			log_file_error(filename, linenum, "Insufficient number of arguments for primitive `%s'!\n", str.c_str());
 
 		std::vector<AstNode*> children_list;
 		for (auto child : children) {
@@ -1301,8 +1399,7 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 		if (str == "bufif0" || str == "bufif1" || str == "notif0" || str == "notif1")
 		{
 			if (children_list.size() != 3)
-				log_error("Invalid number of arguments for primitive `%s' at %s:%d!\n",
-						str.c_str(), filename.c_str(), linenum);
+				log_file_error(filename, linenum, "Invalid number of arguments for primitive `%s'!\n", str.c_str());
 
 			std::vector<RTLIL::State> z_const(1, RTLIL::State::Sz);
 
@@ -1322,6 +1419,7 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 			str.clear();
 			type = AST_ASSIGN;
 			children.push_back(children_list.at(0));
+			children.back()->was_checked = true;
 			children.push_back(node);
 			did_something = true;
 		}
@@ -1358,6 +1456,7 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 			str.clear();
 			type = AST_ASSIGN;
 			children.push_back(children_list[0]);
+			children.back()->was_checked = true;
 			children.push_back(node);
 			did_something = true;
 		}
@@ -1387,8 +1486,7 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 			while (left_at_zero_ast->simplify(true, true, false, stage, -1, false, false)) { }
 			while (right_at_zero_ast->simplify(true, true, false, stage, -1, false, false)) { }
 			if (left_at_zero_ast->type != AST_CONSTANT || right_at_zero_ast->type != AST_CONSTANT)
-				log_error("Unsupported expression on dynamic range select on signal `%s' at %s:%d!\n",
-						str.c_str(), filename.c_str(), linenum);
+				log_file_error(filename, linenum, "Unsupported expression on dynamic range select on signal `%s'!\n", str.c_str());
 			result_width = abs(int(left_at_zero_ast->integer - right_at_zero_ast->integer)) + 1;
 		}
 		did_something = true;
@@ -1415,36 +1513,52 @@ skip_dynamic_range_lvalue_expansion:;
 
 		AstNode *wire_check = new AstNode(AST_WIRE);
 		wire_check->str = id_check;
+		wire_check->was_checked = true;
 		current_ast_mod->children.push_back(wire_check);
 		current_scope[wire_check->str] = wire_check;
 		while (wire_check->simplify(true, false, false, 1, -1, false, false)) { }
 
 		AstNode *wire_en = new AstNode(AST_WIRE);
 		wire_en->str = id_en;
+		wire_en->was_checked = true;
 		current_ast_mod->children.push_back(wire_en);
 		if (current_always_clocked) {
 			current_ast_mod->children.push_back(new AstNode(AST_INITIAL, new AstNode(AST_BLOCK, new AstNode(AST_ASSIGN_LE, new AstNode(AST_IDENTIFIER), AstNode::mkconst_int(0, false, 1)))));
 			current_ast_mod->children.back()->children[0]->children[0]->children[0]->str = id_en;
+			current_ast_mod->children.back()->children[0]->children[0]->children[0]->was_checked = true;
 		}
 		current_scope[wire_en->str] = wire_en;
 		while (wire_en->simplify(true, false, false, 1, -1, false, false)) { }
 
-		std::vector<RTLIL::State> x_bit;
-		x_bit.push_back(RTLIL::State::Sx);
+		AstNode *check_defval;
+		if (type == AST_LIVE || type == AST_FAIR) {
+			check_defval = new AstNode(AST_REDUCE_BOOL, children[0]->clone());
+		} else {
+			std::vector<RTLIL::State> x_bit;
+			x_bit.push_back(RTLIL::State::Sx);
+			check_defval = mkconst_bits(x_bit, false);
+		}
 
-		AstNode *assign_check = new AstNode(AST_ASSIGN_LE, new AstNode(AST_IDENTIFIER), mkconst_bits(x_bit, false));
+		AstNode *assign_check = new AstNode(AST_ASSIGN_LE, new AstNode(AST_IDENTIFIER), check_defval);
 		assign_check->children[0]->str = id_check;
+		assign_check->children[0]->was_checked = true;
 
 		AstNode *assign_en = new AstNode(AST_ASSIGN_LE, new AstNode(AST_IDENTIFIER), mkconst_int(0, false, 1));
 		assign_en->children[0]->str = id_en;
+		assign_en->children[0]->was_checked = true;
 
 		AstNode *default_signals = new AstNode(AST_BLOCK);
 		default_signals->children.push_back(assign_check);
 		default_signals->children.push_back(assign_en);
 		current_top_block->children.insert(current_top_block->children.begin(), default_signals);
 
-		assign_check = new AstNode(AST_ASSIGN_LE, new AstNode(AST_IDENTIFIER), new AstNode(AST_REDUCE_BOOL, children[0]->clone()));
-		assign_check->children[0]->str = id_check;
+		if (type == AST_LIVE || type == AST_FAIR) {
+			assign_check = nullptr;
+		} else {
+			assign_check = new AstNode(AST_ASSIGN_LE, new AstNode(AST_IDENTIFIER), new AstNode(AST_REDUCE_BOOL, children[0]->clone()));
+			assign_check->children[0]->str = id_check;
+			assign_check->children[0]->was_checked = true;
+		}
 
 		if (current_always == nullptr || current_always->type != AST_INITIAL) {
 			assign_en = new AstNode(AST_ASSIGN_LE, new AstNode(AST_IDENTIFIER), mkconst_int(1, false, 1));
@@ -1453,12 +1567,15 @@ skip_dynamic_range_lvalue_expansion:;
 			assign_en->children[1]->str = "\\$initstate";
 		}
 		assign_en->children[0]->str = id_en;
+		assign_en->children[0]->was_checked = true;
 
 		newNode = new AstNode(AST_BLOCK);
-		newNode->children.push_back(assign_check);
+		if (assign_check != nullptr)
+			newNode->children.push_back(assign_check);
 		newNode->children.push_back(assign_en);
 
 		AstNode *assertnode = new AstNode(type);
+		assertnode->str = str;
 		assertnode->children.push_back(new AstNode(AST_IDENTIFIER));
 		assertnode->children.push_back(new AstNode(AST_IDENTIFIER));
 		assertnode->children[0]->str = id_check;
@@ -1504,11 +1621,13 @@ skip_dynamic_range_lvalue_expansion:;
 			current_scope[wire_tmp->str] = wire_tmp;
 			wire_tmp->attributes["\\nosync"] = AstNode::mkconst_int(1, false);
 			while (wire_tmp->simplify(true, false, false, 1, -1, false, false)) { }
+			wire_tmp->is_logic = true;
 
 			AstNode *wire_tmp_id = new AstNode(AST_IDENTIFIER);
 			wire_tmp_id->str = wire_tmp->str;
 
 			newNode->children.push_back(new AstNode(AST_ASSIGN_EQ, wire_tmp_id, children[1]->clone()));
+			newNode->children.back()->was_checked = true;
 
 			int cursor = 0;
 			for (auto child : children[0]->children)
@@ -1538,14 +1657,6 @@ skip_dynamic_range_lvalue_expansion:;
 		sstr << "$memwr$" << children[0]->str << "$" << filename << ":" << linenum << "$" << (autoidx++);
 		std::string id_addr = sstr.str() + "_ADDR", id_data = sstr.str() + "_DATA", id_en = sstr.str() + "_EN";
 
-		if (type == AST_ASSIGN_EQ) {
-			pair<string, int> this_blocking_assignment_warn(filename, linenum);
-			if (this_blocking_assignment_warn != last_blocking_assignment_warn)
-				log_warning("Blocking assignment to memory in line %s:%d is handled like a non-blocking assignment.\n",
-						filename.c_str(), linenum);
-			last_blocking_assignment_warn = this_blocking_assignment_warn;
-		}
-
 		int mem_width, mem_size, addr_bits;
 		bool mem_signed = children[0]->id2ast->is_signed;
 		children[0]->id2ast->meminfo(mem_width, mem_size, addr_bits);
@@ -1561,12 +1672,14 @@ skip_dynamic_range_lvalue_expansion:;
 
 		AstNode *wire_addr = new AstNode(AST_WIRE, new AstNode(AST_RANGE, mkconst_int(addr_bits-1, true), mkconst_int(0, true)));
 		wire_addr->str = id_addr;
+		wire_addr->was_checked = true;
 		current_ast_mod->children.push_back(wire_addr);
 		current_scope[wire_addr->str] = wire_addr;
 		while (wire_addr->simplify(true, false, false, 1, -1, false, false)) { }
 
 		AstNode *wire_data = new AstNode(AST_WIRE, new AstNode(AST_RANGE, mkconst_int(mem_width-1, true), mkconst_int(0, true)));
 		wire_data->str = id_data;
+		wire_data->was_checked = true;
 		wire_data->is_signed = mem_signed;
 		current_ast_mod->children.push_back(wire_data);
 		current_scope[wire_data->str] = wire_data;
@@ -1576,6 +1689,7 @@ skip_dynamic_range_lvalue_expansion:;
 		if (current_always->type != AST_INITIAL) {
 			wire_en = new AstNode(AST_WIRE, new AstNode(AST_RANGE, mkconst_int(mem_width-1, true), mkconst_int(0, true)));
 			wire_en->str = id_en;
+			wire_en->was_checked = true;
 			current_ast_mod->children.push_back(wire_en);
 			current_scope[wire_en->str] = wire_en;
 			while (wire_en->simplify(true, false, false, 1, -1, false, false)) { }
@@ -1591,14 +1705,17 @@ skip_dynamic_range_lvalue_expansion:;
 
 		AstNode *assign_addr = new AstNode(AST_ASSIGN_LE, new AstNode(AST_IDENTIFIER), mkconst_bits(x_bits_addr, false));
 		assign_addr->children[0]->str = id_addr;
+		assign_addr->children[0]->was_checked = true;
 
 		AstNode *assign_data = new AstNode(AST_ASSIGN_LE, new AstNode(AST_IDENTIFIER), mkconst_bits(x_bits_data, false));
 		assign_data->children[0]->str = id_data;
+		assign_data->children[0]->was_checked = true;
 
 		AstNode *assign_en = nullptr;
 		if (current_always->type != AST_INITIAL) {
 			assign_en = new AstNode(AST_ASSIGN_LE, new AstNode(AST_IDENTIFIER), mkconst_int(0, false, mem_width));
 			assign_en->children[0]->str = id_en;
+			assign_en->children[0]->was_checked = true;
 		}
 
 		AstNode *default_signals = new AstNode(AST_BLOCK);
@@ -1610,6 +1727,7 @@ skip_dynamic_range_lvalue_expansion:;
 
 		assign_addr = new AstNode(AST_ASSIGN_LE, new AstNode(AST_IDENTIFIER), children[0]->children[0]->children[0]->clone());
 		assign_addr->children[0]->str = id_addr;
+		assign_addr->children[0]->was_checked = true;
 
 		if (children[0]->children.size() == 2)
 		{
@@ -1624,12 +1742,14 @@ skip_dynamic_range_lvalue_expansion:;
 				assign_data = new AstNode(AST_ASSIGN_LE, new AstNode(AST_IDENTIFIER),
 						new AstNode(AST_CONCAT, mkconst_bits(padding_x, false), children[1]->clone()));
 				assign_data->children[0]->str = id_data;
+				assign_data->children[0]->was_checked = true;
 
 				if (current_always->type != AST_INITIAL) {
 					for (int i = 0; i < mem_width; i++)
 						set_bits_en[i] = offset <= i && i < offset+width ? RTLIL::State::S1 : RTLIL::State::S0;
 					assign_en = new AstNode(AST_ASSIGN_LE, new AstNode(AST_IDENTIFIER), mkconst_bits(set_bits_en, false));
 					assign_en->children[0]->str = id_en;
+					assign_en->children[0]->was_checked = true;
 				}
 			}
 			else
@@ -1645,12 +1765,13 @@ skip_dynamic_range_lvalue_expansion:;
 				while (left_at_zero_ast->simplify(true, true, false, 1, -1, false, false)) { }
 				while (right_at_zero_ast->simplify(true, true, false, 1, -1, false, false)) { }
 				if (left_at_zero_ast->type != AST_CONSTANT || right_at_zero_ast->type != AST_CONSTANT)
-					log_error("Unsupported expression on dynamic range select on signal `%s' at %s:%d!\n", str.c_str(), filename.c_str(), linenum);
-				int width = left_at_zero_ast->integer - right_at_zero_ast->integer + 1;
+					log_file_error(filename, linenum, "Unsupported expression on dynamic range select on signal `%s'!\n", str.c_str());
+				int width = abs(int(left_at_zero_ast->integer - right_at_zero_ast->integer)) + 1;
 
 				assign_data = new AstNode(AST_ASSIGN_LE, new AstNode(AST_IDENTIFIER),
 						new AstNode(AST_SHIFT_LEFT, children[1]->clone(), offset_ast->clone()));
 				assign_data->children[0]->str = id_data;
+				assign_data->children[0]->was_checked = true;
 
 				if (current_always->type != AST_INITIAL) {
 					for (int i = 0; i < mem_width; i++)
@@ -1658,6 +1779,7 @@ skip_dynamic_range_lvalue_expansion:;
 					assign_en = new AstNode(AST_ASSIGN_LE, new AstNode(AST_IDENTIFIER),
 							new AstNode(AST_SHIFT_LEFT, mkconst_bits(set_bits_en, false), offset_ast->clone()));
 					assign_en->children[0]->str = id_en;
+					assign_en->children[0]->was_checked = true;
 				}
 
 				delete left_at_zero_ast;
@@ -1669,10 +1791,12 @@ skip_dynamic_range_lvalue_expansion:;
 		{
 			assign_data = new AstNode(AST_ASSIGN_LE, new AstNode(AST_IDENTIFIER), children[1]->clone());
 			assign_data->children[0]->str = id_data;
+			assign_data->children[0]->was_checked = true;
 
 			if (current_always->type != AST_INITIAL) {
 				assign_en = new AstNode(AST_ASSIGN_LE, new AstNode(AST_IDENTIFIER), mkconst_bits(set_bits_en, false));
 				assign_en->children[0]->str = id_en;
+				assign_en->children[0]->was_checked = true;
 			}
 		}
 
@@ -1731,25 +1855,25 @@ skip_dynamic_range_lvalue_expansion:;
 
 			if (str == "\\$past")
 			{
-				if (width_hint <= 0)
+				if (width_hint < 0)
 					goto replace_fcall_later;
 
 				int num_steps = 1;
 
 				if (GetSize(children) != 1 && GetSize(children) != 2)
-					log_error("System function %s got %d arguments, expected 1 or 2 at %s:%d.\n",
-							RTLIL::unescape_id(str).c_str(), int(children.size()), filename.c_str(), linenum);
+					log_file_error(filename, linenum, "System function %s got %d arguments, expected 1 or 2.\n",
+							RTLIL::unescape_id(str).c_str(), int(children.size()));
 
 				if (!current_always_clocked)
-					log_error("System function %s is only allowed in clocked blocks at %s:%d.\n",
-							RTLIL::unescape_id(str).c_str(), filename.c_str(), linenum);
+					log_file_error(filename, linenum, "System function %s is only allowed in clocked blocks.\n",
+							RTLIL::unescape_id(str).c_str());
 
 				if (GetSize(children) == 2)
 				{
 					AstNode *buf = children[1]->clone();
-					while (buf->simplify(true, false, false, stage, width_hint, sign_hint, false)) { }
+					while (buf->simplify(true, false, false, stage, -1, false, false)) { }
 					if (buf->type != AST_CONSTANT)
-						log_error("Failed to evaluate system function `%s' with non-constant value at %s:%d.\n", str.c_str(), filename.c_str(), linenum);
+						log_file_error(filename, linenum, "Failed to evaluate system function `%s' with non-constant value.\n", str.c_str());
 
 					num_steps = buf->asInt(true);
 					delete buf;
@@ -1763,6 +1887,11 @@ skip_dynamic_range_lvalue_expansion:;
 
 				log_assert(block != nullptr);
 
+				if (num_steps == 0) {
+					newNode = children[0]->clone();
+					goto apply_newNode;
+				}
+
 				int myidx = autoidx++;
 				AstNode *outreg = nullptr;
 
@@ -1781,6 +1910,7 @@ skip_dynamic_range_lvalue_expansion:;
 					AstNode *regid = new AstNode(AST_IDENTIFIER);
 					regid->str = reg->str;
 					regid->id2ast = reg;
+					regid->was_checked = true;
 
 					AstNode *rhs = nullptr;
 
@@ -1802,15 +1932,15 @@ skip_dynamic_range_lvalue_expansion:;
 				goto apply_newNode;
 			}
 
-			if (str == "\\$stable" || str == "\\$rose" || str == "\\$fell")
+			if (str == "\\$stable" || str == "\\$rose" || str == "\\$fell" || str == "\\$changed")
 			{
 				if (GetSize(children) != 1)
-					log_error("System function %s got %d arguments, expected 1 at %s:%d.\n",
-							RTLIL::unescape_id(str).c_str(), int(children.size()), filename.c_str(), linenum);
+					log_file_error(filename, linenum, "System function %s got %d arguments, expected 1.\n",
+							RTLIL::unescape_id(str).c_str(), int(children.size()));
 
 				if (!current_always_clocked)
-					log_error("System function %s is only allowed in clocked blocks at %s:%d.\n",
-							RTLIL::unescape_id(str).c_str(), filename.c_str(), linenum);
+					log_file_error(filename, linenum, "System function %s is only allowed in clocked blocks.\n",
+							RTLIL::unescape_id(str).c_str());
 
 				AstNode *present = children.at(0)->clone();
 				AstNode *past = clone();
@@ -1819,11 +1949,18 @@ skip_dynamic_range_lvalue_expansion:;
 				if (str == "\\$stable")
 					newNode = new AstNode(AST_EQ, past, present);
 
+				else if (str == "\\$changed")
+					newNode = new AstNode(AST_NE, past, present);
+
 				else if (str == "\\$rose")
-					newNode = new AstNode(AST_LOGIC_AND, new AstNode(AST_LOGIC_NOT, past), present);
+					newNode = new AstNode(AST_LOGIC_AND,
+							new AstNode(AST_LOGIC_NOT, new AstNode(AST_BIT_AND, past, mkconst_int(1,false))),
+							new AstNode(AST_BIT_AND, present, mkconst_int(1,false)));
 
 				else if (str == "\\$fell")
-					newNode = new AstNode(AST_LOGIC_AND, past, new AstNode(AST_LOGIC_NOT, present));
+					newNode = new AstNode(AST_LOGIC_AND,
+							new AstNode(AST_BIT_AND, past, mkconst_int(1,false)),
+							new AstNode(AST_LOGIC_NOT, new AstNode(AST_BIT_AND, present, mkconst_int(1,false))));
 
 				else
 					log_abort();
@@ -1840,13 +1977,13 @@ skip_dynamic_range_lvalue_expansion:;
 			if (str == "\\$clog2")
 			{
 				if (children.size() != 1)
-					log_error("System function %s got %d arguments, expected 1 at %s:%d.\n",
-							RTLIL::unescape_id(str).c_str(), int(children.size()), filename.c_str(), linenum);
+					log_file_error(filename, linenum, "System function %s got %d arguments, expected 1.\n",
+							RTLIL::unescape_id(str).c_str(), int(children.size()));
 
 				AstNode *buf = children[0]->clone();
 				while (buf->simplify(true, false, false, stage, width_hint, sign_hint, false)) { }
 				if (buf->type != AST_CONSTANT)
-					log_error("Failed to evaluate system function `%s' with non-constant value at %s:%d.\n", str.c_str(), filename.c_str(), linenum);
+					log_file_error(filename, linenum, "Failed to evaluate system function `%s' with non-constant value.\n", str.c_str());
 
 				RTLIL::Const arg_value = buf->bitsAsConst();
 				if (arg_value.as_bool())
@@ -1858,19 +1995,19 @@ skip_dynamic_range_lvalue_expansion:;
 					if (arg_value.bits.at(i) == RTLIL::State::S1)
 						result = i + 1;
 
-				newNode = mkconst_int(result, false);
+				newNode = mkconst_int(result, true);
 				goto apply_newNode;
 			}
 
 			if (str == "\\$size" || str == "\\$bits")
 			{
 				if (str == "\\$bits" && children.size() != 1)
-					log_error("System function %s got %d arguments, expected 1 at %s:%d.\n",
-							RTLIL::unescape_id(str).c_str(), int(children.size()), filename.c_str(), linenum);
+					log_file_error(filename, linenum, "System function %s got %d arguments, expected 1.\n",
+							RTLIL::unescape_id(str).c_str(), int(children.size()));
 
 				if (str == "\\$size" && children.size() != 1 && children.size() != 2)
-					log_error("System function %s got %d arguments, expected 1 or 2 at %s:%d.\n",
-							RTLIL::unescape_id(str).c_str(), int(children.size()), filename.c_str(), linenum);
+					log_file_error(filename, linenum, "System function %s got %d arguments, expected 1 or 2.\n",
+							RTLIL::unescape_id(str).c_str(), int(children.size()));
 
 				int dim = 1;
 				if (str == "\\$size" && children.size() == 2) {
@@ -1893,7 +2030,7 @@ skip_dynamic_range_lvalue_expansion:;
 					if (id_ast == NULL && current_scope.count(buf->str))
 						id_ast = current_scope.at(buf->str);
 					if (!id_ast)
-						log_error("Failed to resolve identifier %s for width detection at %s:%d!\n", buf->str.c_str(), filename.c_str(), linenum);
+						log_file_error(filename, linenum, "Failed to resolve identifier %s for width detection!\n", buf->str.c_str());
 					if (id_ast->type == AST_MEMORY) {
 						// We got here only if the argument is a memory
 						// Otherwise $size() and $bits() return the expression width
@@ -1901,15 +2038,15 @@ skip_dynamic_range_lvalue_expansion:;
 						if (str == "\\$bits") {
 							if (mem_range->type == AST_RANGE) {
 								if (!mem_range->range_valid)
-									log_error("Failed to detect width of memory access `%s' at %s:%d!\n", buf->str.c_str(), filename.c_str(), linenum);
+									log_file_error(filename, linenum, "Failed to detect width of memory access `%s'!\n", buf->str.c_str());
 								mem_depth = mem_range->range_left - mem_range->range_right + 1;
 							} else
-								log_error("Unknown memory depth AST type in `%s' at %s:%d!\n", buf->str.c_str(), filename.c_str(), linenum);
+								log_file_error(filename, linenum, "Unknown memory depth AST type in `%s'!\n", buf->str.c_str());
 						} else {
 							// $size()
 							if (mem_range->type == AST_RANGE) {
 								if (!mem_range->range_valid)
-									log_error("Failed to detect width of memory access `%s' at %s:%d!\n", buf->str.c_str(), filename.c_str(), linenum);
+									log_file_error(filename, linenum, "Failed to detect width of memory access `%s'!\n", buf->str.c_str());
 								int dims;
 								if (id_ast->multirange_dimensions.empty())
 									dims = 1;
@@ -1920,9 +2057,9 @@ skip_dynamic_range_lvalue_expansion:;
 								else if (dim <= dims) {
 									width_hint = id_ast->multirange_dimensions[2*dim-1];
 								} else if ((dim > dims+1) || (dim < 0))
-									log_error("Dimension %d out of range in `%s', as it only has dimensions 1..%d at %s:%d!\n", dim, buf->str.c_str(), dims+1, filename.c_str(), linenum);
+									log_file_error(filename, linenum, "Dimension %d out of range in `%s', as it only has dimensions 1..%d!\n", dim, buf->str.c_str(), dims+1);
 							} else
-								log_error("Unknown memory depth AST type in `%s' at %s:%d!\n", buf->str.c_str(), filename.c_str(), linenum);
+								log_file_error(filename, linenum, "Unknown memory depth AST type in `%s'!\n", buf->str.c_str());
 						}
 					}
 				}
@@ -1943,19 +2080,19 @@ skip_dynamic_range_lvalue_expansion:;
 
 				if (func_with_two_arguments) {
 					if (children.size() != 2)
-						log_error("System function %s got %d arguments, expected 2 at %s:%d.\n",
-								RTLIL::unescape_id(str).c_str(), int(children.size()), filename.c_str(), linenum);
+						log_file_error(filename, linenum, "System function %s got %d arguments, expected 2.\n",
+								RTLIL::unescape_id(str).c_str(), int(children.size()));
 				} else {
 					if (children.size() != 1)
-						log_error("System function %s got %d arguments, expected 1 at %s:%d.\n",
-								RTLIL::unescape_id(str).c_str(), int(children.size()), filename.c_str(), linenum);
+						log_file_error(filename, linenum, "System function %s got %d arguments, expected 1.\n",
+								RTLIL::unescape_id(str).c_str(), int(children.size()));
 				}
 
 				if (children.size() >= 1) {
 					while (children[0]->simplify(true, false, false, stage, width_hint, sign_hint, false)) { }
 					if (!children[0]->isConst())
-						log_error("Failed to evaluate system function `%s' with non-constant argument at %s:%d.\n",
-								RTLIL::unescape_id(str).c_str(), filename.c_str(), linenum);
+						log_file_error(filename, linenum, "Failed to evaluate system function `%s' with non-constant argument.\n",
+								RTLIL::unescape_id(str).c_str());
 					int child_width_hint = width_hint;
 					bool child_sign_hint = sign_hint;
 					children[0]->detectSignWidth(child_width_hint, child_sign_hint);
@@ -1965,8 +2102,8 @@ skip_dynamic_range_lvalue_expansion:;
 				if (children.size() >= 2) {
 					while (children[1]->simplify(true, false, false, stage, width_hint, sign_hint, false)) { }
 					if (!children[1]->isConst())
-						log_error("Failed to evaluate system function `%s' with non-constant argument at %s:%d.\n",
-								RTLIL::unescape_id(str).c_str(), filename.c_str(), linenum);
+						log_file_error(filename, linenum, "Failed to evaluate system function `%s' with non-constant argument.\n",
+								RTLIL::unescape_id(str).c_str());
 					int child_width_hint = width_hint;
 					bool child_sign_hint = sign_hint;
 					children[1]->detectSignWidth(child_width_hint, child_sign_hint);
@@ -2018,14 +2155,14 @@ skip_dynamic_range_lvalue_expansion:;
 				for (int i = 2; i < GetSize(dpi_decl->children); i++)
 				{
 					if (i-2 >= GetSize(children))
-						log_error("Insufficient number of arguments in DPI function call at %s:%d.\n", filename.c_str(), linenum);
+						log_file_error(filename, linenum, "Insufficient number of arguments in DPI function call.\n");
 
 					argtypes.push_back(RTLIL::unescape_id(dpi_decl->children.at(i)->str));
 					args.push_back(children.at(i-2)->clone());
 					while (args.back()->simplify(true, false, false, stage, -1, false, true)) { }
 
 					if (args.back()->type != AST_CONSTANT && args.back()->type != AST_REALVALUE)
-						log_error("Failed to evaluate DPI function with non-constant argument at %s:%d.\n", filename.c_str(), linenum);
+						log_file_error(filename, linenum, "Failed to evaluate DPI function with non-constant argument.\n");
 				}
 
 				newNode = dpi_call(rtype, fname, argtypes, args);
@@ -2037,7 +2174,7 @@ skip_dynamic_range_lvalue_expansion:;
 			}
 
 			if (current_scope.count(str) == 0 || current_scope[str]->type != AST_FUNCTION)
-				log_error("Can't resolve function name `%s' at %s:%d.\n", str.c_str(), filename.c_str(), linenum);
+				log_file_error(filename, linenum, "Can't resolve function name `%s'.\n", str.c_str());
 		}
 
 		if (type == AST_TCALL)
@@ -2045,26 +2182,26 @@ skip_dynamic_range_lvalue_expansion:;
 			if (str == "$finish" || str == "$stop")
 			{
 				if (!current_always || current_always->type != AST_INITIAL)
-					log_error("System task `%s' outside initial block is unsupported at %s:%d.\n", str.c_str(), filename.c_str(), linenum);
+					log_file_error(filename, linenum, "System task `%s' outside initial block is unsupported.\n", str.c_str());
 
-				log_error("System task `%s' executed at %s:%d.\n", str.c_str(), filename.c_str(), linenum);
+				log_file_error(filename, linenum, "System task `%s' executed.\n", str.c_str());
 			}
 
 			if (str == "\\$readmemh" || str == "\\$readmemb")
 			{
 				if (GetSize(children) < 2 || GetSize(children) > 4)
-					log_error("System function %s got %d arguments, expected 2-4 at %s:%d.\n",
-							RTLIL::unescape_id(str).c_str(), int(children.size()), filename.c_str(), linenum);
+					log_file_error(filename, linenum, "System function %s got %d arguments, expected 2-4.\n",
+							RTLIL::unescape_id(str).c_str(), int(children.size()));
 
 				AstNode *node_filename = children[0]->clone();
 				while (node_filename->simplify(true, false, false, stage, width_hint, sign_hint, false)) { }
 				if (node_filename->type != AST_CONSTANT)
-					log_error("Failed to evaluate system function `%s' with non-constant 1st argument at %s:%d.\n", str.c_str(), filename.c_str(), linenum);
+					log_file_error(filename, linenum, "Failed to evaluate system function `%s' with non-constant 1st argument.\n", str.c_str());
 
 				AstNode *node_memory = children[1]->clone();
 				while (node_memory->simplify(true, false, false, stage, width_hint, sign_hint, false)) { }
 				if (node_memory->type != AST_IDENTIFIER || node_memory->id2ast == nullptr || node_memory->id2ast->type != AST_MEMORY)
-					log_error("Failed to evaluate system function `%s' with non-memory 2nd argument at %s:%d.\n", str.c_str(), filename.c_str(), linenum);
+					log_file_error(filename, linenum, "Failed to evaluate system function `%s' with non-memory 2nd argument.\n", str.c_str());
 
 				int start_addr = -1, finish_addr = -1;
 
@@ -2072,7 +2209,7 @@ skip_dynamic_range_lvalue_expansion:;
 					AstNode *node_addr = children[2]->clone();
 					while (node_addr->simplify(true, false, false, stage, width_hint, sign_hint, false)) { }
 					if (node_addr->type != AST_CONSTANT)
-						log_error("Failed to evaluate system function `%s' with non-constant 3rd argument at %s:%d.\n", str.c_str(), filename.c_str(), linenum);
+						log_file_error(filename, linenum, "Failed to evaluate system function `%s' with non-constant 3rd argument.\n", str.c_str());
 					start_addr = int(node_addr->asInt(false));
 				}
 
@@ -2080,7 +2217,7 @@ skip_dynamic_range_lvalue_expansion:;
 					AstNode *node_addr = children[3]->clone();
 					while (node_addr->simplify(true, false, false, stage, width_hint, sign_hint, false)) { }
 					if (node_addr->type != AST_CONSTANT)
-						log_error("Failed to evaluate system function `%s' with non-constant 4th argument at %s:%d.\n", str.c_str(), filename.c_str(), linenum);
+						log_file_error(filename, linenum, "Failed to evaluate system function `%s' with non-constant 4th argument.\n", str.c_str());
 					finish_addr = int(node_addr->asInt(false));
 				}
 
@@ -2102,11 +2239,13 @@ skip_dynamic_range_lvalue_expansion:;
 				}
 
 				newNode = readmem(str == "\\$readmemh", node_filename->bitsAsConst().decode_string(), node_memory->id2ast, start_addr, finish_addr, unconditional_init);
+				delete node_filename;
+				delete node_memory;
 				goto apply_newNode;
 			}
 
 			if (current_scope.count(str) == 0 || current_scope[str]->type != AST_TASK)
-				log_error("Can't resolve task name `%s' at %s:%d.\n", str.c_str(), filename.c_str(), linenum);
+				log_file_error(filename, linenum, "Can't resolve task name `%s'.\n", str.c_str());
 		}
 
 		AstNode *decl = current_scope[str];
@@ -2134,15 +2273,17 @@ skip_dynamic_range_lvalue_expansion:;
 			}
 
 			if (in_param)
-				log_error("Non-constant function call in constant expression at %s:%d.\n", filename.c_str(), linenum);
+				log_file_error(filename, linenum, "Non-constant function call in constant expression.\n");
 			if (require_const_eval)
-				log_error("Function %s can only be called with constant arguments at %s:%d.\n", str.c_str(), filename.c_str(), linenum);
+				log_file_error(filename, linenum, "Function %s can only be called with constant arguments.\n", str.c_str());
 		}
 
 		size_t arg_count = 0;
 		std::map<std::string, std::string> replace_rules;
 		vector<AstNode*> added_mod_children;
 		dict<std::string, AstNode*> wire_cache;
+		vector<AstNode*> new_stmts;
+		vector<AstNode*> output_assignments;
 
 		if (current_block == NULL)
 		{
@@ -2167,6 +2308,8 @@ skip_dynamic_range_lvalue_expansion:;
 
 			AstNode *always = new AstNode(AST_ALWAYS, new AstNode(AST_BLOCK,
 					new AstNode(AST_ASSIGN_EQ, lvalue, clone())));
+			always->children[0]->children[0]->was_checked = true;
+
 			current_ast_mod->children.push_back(always);
 
 			goto replace_fcall_with_id;
@@ -2192,7 +2335,7 @@ skip_dynamic_range_lvalue_expansion:;
 				if (attr.first.str().rfind("\\via_celltype_defparam_", 0) == 0)
 				{
 					AstNode *cell_arg = new AstNode(AST_PARASET, attr.second->clone());
-					cell_arg->str = RTLIL::escape_id(attr.first.str().substr(strlen("\\via_celltype_defparam_")));
+					cell_arg->str = RTLIL::escape_id(attr.first.substr(strlen("\\via_celltype_defparam_")));
 					cell->children.push_back(cell_arg);
 				}
 
@@ -2216,6 +2359,7 @@ skip_dynamic_range_lvalue_expansion:;
 						AstNode *assign = child->is_input ?
 								new AstNode(AST_ASSIGN_EQ, wire_id->clone(), arg) :
 								new AstNode(AST_ASSIGN_EQ, arg, wire_id->clone());
+						assign->children[0]->was_checked = true;
 
 						for (auto it = current_block->children.begin(); it != current_block->children.end(); it++) {
 							if (*it != current_block_child)
@@ -2253,7 +2397,7 @@ skip_dynamic_range_lvalue_expansion:;
 									goto tcall_incompatible_wires;
 						} else {
 					tcall_incompatible_wires:
-							log_error("Incompatible re-declaration of wire %s at %s:%d.\n", child->str.c_str(), filename.c_str(), linenum);
+							log_file_error(filename, linenum, "Incompatible re-declaration of wire %s.\n", child->str.c_str());
 						}
 					}
 				}
@@ -2264,8 +2408,8 @@ skip_dynamic_range_lvalue_expansion:;
 					wire->port_id = 0;
 					wire->is_input = false;
 					wire->is_output = false;
-					if (!child->is_output)
-						wire->attributes["\\nosync"] = AstNode::mkconst_int(1, false);
+					wire->is_reg = true;
+					wire->attributes["\\nosync"] = AstNode::mkconst_int(1, false);
 					wire_cache[child->str] = wire;
 
 					current_ast_mod->children.push_back(wire);
@@ -2286,13 +2430,11 @@ skip_dynamic_range_lvalue_expansion:;
 					AstNode *assign = child->is_input ?
 							new AstNode(AST_ASSIGN_EQ, wire_id, arg) :
 							new AstNode(AST_ASSIGN_EQ, arg, wire_id);
-
-					for (auto it = current_block->children.begin(); it != current_block->children.end(); it++) {
-						if (*it != current_block_child)
-							continue;
-						current_block->children.insert(it, assign);
-						break;
-					}
+					assign->children[0]->was_checked = true;
+					if (child->is_input)
+						new_stmts.push_back(assign);
+					else
+						output_assignments.push_back(assign);
 				}
 			}
 
@@ -2306,14 +2448,18 @@ skip_dynamic_range_lvalue_expansion:;
 			{
 				AstNode *stmt = child->clone();
 				stmt->replace_ids(prefix, replace_rules);
+				new_stmts.push_back(stmt);
+			}
 
-				for (auto it = current_block->children.begin(); it != current_block->children.end(); it++) {
-					if (*it != current_block_child)
-						continue;
-					current_block->children.insert(it, stmt);
-					break;
-				}
+		new_stmts.insert(new_stmts.end(), output_assignments.begin(), output_assignments.end());
+
+		for (auto it = current_block->children.begin(); ; it++) {
+			log_assert(it != current_block->children.end());
+			if (*it == current_block_child) {
+				current_block->children.insert(it, new_stmts.begin(), new_stmts.end());
+				break;
 			}
+		}
 
 	replace_fcall_with_id:
 		if (type == AST_FCALL) {
@@ -2641,7 +2787,7 @@ AstNode *AstNode::readmem(bool is_readmemh, std::string mem_filename, AstNode *m
 	yosys_input_files.insert(mem_filename);
 
 	if (f.fail())
-		log_error("Can not open file `%s` for %s at %s:%d.\n", mem_filename.c_str(), str.c_str(), filename.c_str(), linenum);
+		log_file_error(filename, linenum, "Can not open file `%s` for %s.\n", mem_filename.c_str(), str.c_str());
 
 	log_assert(GetSize(memory->children) == 2 && memory->children[1]->type == AST_RANGE && memory->children[1]->range_valid);
 	int range_left =  memory->children[1]->range_left, range_right =  memory->children[1]->range_right;
@@ -2663,13 +2809,13 @@ AstNode *AstNode::readmem(bool is_readmemh, std::string mem_filename, AstNode *m
 		std::getline(f, line);
 
 		for (int i = 0; i < GetSize(line); i++) {
-			if (in_comment && line.substr(i, 2) == "*/") {
+			if (in_comment && line.compare(i, 2, "*/") == 0) {
 				line[i] = ' ';
 				line[i+1] = ' ';
 				in_comment = false;
 				continue;
 			}
-			if (!in_comment && line.substr(i, 2) == "/*")
+			if (!in_comment && line.compare(i, 2, "/*") == 0)
 				in_comment = true;
 			if (in_comment)
 				line[i] = ' ';
@@ -2678,7 +2824,7 @@ AstNode *AstNode::readmem(bool is_readmemh, std::string mem_filename, AstNode *m
 		while (1)
 		{
 			token = next_token(line, " \t\r\n");
-			if (token.empty() || token.substr(0, 2) == "//")
+			if (token.empty() || token.compare(0, 2, "//") == 0)
 				break;
 
 			if (token[0] == '@') {
@@ -2687,7 +2833,7 @@ AstNode *AstNode::readmem(bool is_readmemh, std::string mem_filename, AstNode *m
 				char *endptr;
 				cursor = strtol(nptr, &endptr, 16);
 				if (!*nptr || *endptr)
-					log_error("Can not parse address `%s` for %s at %s:%d.\n", nptr, str.c_str(), filename.c_str(), linenum);
+					log_file_error(filename, linenum, "Can not parse address `%s` for %s.\n", nptr, str.c_str());
 				continue;
 			}
 
@@ -2725,6 +2871,7 @@ AstNode *AstNode::readmem(bool is_readmemh, std::string mem_filename, AstNode *m
 				block->children.push_back(new AstNode(AST_ASSIGN_EQ, new AstNode(AST_IDENTIFIER, new AstNode(AST_RANGE, AstNode::mkconst_int(cursor, false))), value));
 				block->children.back()->children[0]->str = memory->str;
 				block->children.back()->children[0]->id2ast = memory;
+				block->children.back()->children[0]->was_checked = true;
 			}
 
 			cursor += increment;
@@ -2748,8 +2895,15 @@ AstNode *AstNode::readmem(bool is_readmemh, std::string mem_filename, AstNode *m
 void AstNode::expand_genblock(std::string index_var, std::string prefix, std::map<std::string, std::string> &name_map)
 {
 	if (!index_var.empty() && type == AST_IDENTIFIER && str == index_var) {
-		current_scope[index_var]->children[0]->cloneInto(this);
-		return;
+		if (children.empty()) {
+			current_scope[index_var]->children[0]->cloneInto(this);
+		} else {
+			AstNode *p = new AstNode(AST_LOCALPARAM, current_scope[index_var]->children[0]->clone());
+			p->str = stringf("$genval$%d", autoidx++);
+			current_ast_mod->children.push_back(p);
+			str = p->str;
+			id2ast = p;
+		}
 	}
 
 	if ((type == AST_IDENTIFIER || type == AST_FCALL || type == AST_TCALL) && name_map.count(str) > 0)
@@ -2783,7 +2937,11 @@ void AstNode::expand_genblock(std::string index_var, std::string prefix, std::ma
 
 	for (size_t i = 0; i < children.size(); i++) {
 		AstNode *child = children[i];
-		if (child->type != AST_FUNCTION && child->type != AST_TASK && child->type != AST_PREFIX)
+		// AST_PREFIX member names should not be prefixed; a nested AST_PREFIX
+		// still needs to recursed-into
+		if (type == AST_PREFIX && i == 1 && child->type == AST_IDENTIFIER)
+			continue;
+		if (child->type != AST_FUNCTION && child->type != AST_TASK)
 			child->expand_genblock(index_var, prefix, name_map);
 	}
 
@@ -2838,7 +2996,7 @@ void AstNode::mem2reg_as_needed_pass1(dict<AstNode*, pool<std::string>> &mem2reg
 		dict<AstNode*, uint32_t> &mem2reg_candidates, dict<AstNode*, uint32_t> &proc_flags, uint32_t &flags)
 {
 	uint32_t children_flags = 0;
-	int ignore_children_counter = 0;
+	int lhs_children_counter = 0;
 
 	if (type == AST_ASSIGN || type == AST_ASSIGN_LE || type == AST_ASSIGN_EQ)
 	{
@@ -2864,6 +3022,16 @@ void AstNode::mem2reg_as_needed_pass1(dict<AstNode*, pool<std::string>> &mem2reg
 				proc_flags[mem] |= AstNode::MEM2REG_FL_EQ1;
 			}
 
+			// for proper (non-init) writes: remember if this is a constant index or not
+			if ((flags & MEM2REG_FL_INIT) == 0) {
+				if (children[0]->children.size() && children[0]->children[0]->type == AST_RANGE && children[0]->children[0]->children.size()) {
+					if (children[0]->children[0]->children[0]->type == AST_CONSTANT)
+						mem2reg_candidates[mem] |= AstNode::MEM2REG_FL_CONST_LHS;
+					else
+						mem2reg_candidates[mem] |= AstNode::MEM2REG_FL_VAR_LHS;
+				}
+			}
+
 			// remember where this is
 			if (flags & MEM2REG_FL_INIT) {
 				if (!(mem2reg_candidates[mem] & AstNode::MEM2REG_FL_SET_INIT))
@@ -2876,7 +3044,7 @@ void AstNode::mem2reg_as_needed_pass1(dict<AstNode*, pool<std::string>> &mem2reg
 			}
 		}
 
-		ignore_children_counter = 1;
+		lhs_children_counter = 1;
 	}
 
 	if (type == AST_IDENTIFIER && id2ast && id2ast->type == AST_MEMORY)
@@ -2919,12 +3087,23 @@ void AstNode::mem2reg_as_needed_pass1(dict<AstNode*, pool<std::string>> &mem2reg
 	log_assert((flags & ~0x000000ff) == 0);
 
 	for (auto child : children)
-		if (ignore_children_counter > 0)
-			ignore_children_counter--;
-		else if (proc_flags_p)
+	{
+		if (lhs_children_counter > 0) {
+			lhs_children_counter--;
+			if (child->children.size() && child->children[0]->type == AST_RANGE && child->children[0]->children.size()) {
+				for (auto c : child->children[0]->children) {
+					if (proc_flags_p)
+						c->mem2reg_as_needed_pass1(mem2reg_places, mem2reg_candidates, *proc_flags_p, flags);
+					else
+						c->mem2reg_as_needed_pass1(mem2reg_places, mem2reg_candidates, proc_flags, flags);
+				}
+			}
+		} else
+		if (proc_flags_p)
 			child->mem2reg_as_needed_pass1(mem2reg_places, mem2reg_candidates, *proc_flags_p, flags);
 		else
 			child->mem2reg_as_needed_pass1(mem2reg_places, mem2reg_candidates, proc_flags, flags);
+	}
 
 	flags &= ~children_flags | backup_flags;
 
@@ -2943,7 +3122,7 @@ bool AstNode::mem2reg_check(pool<AstNode*> &mem2reg_set)
 		return false;
 
 	if (children.empty() || children[0]->type != AST_RANGE || GetSize(children[0]->children) != 1)
-		log_error("Invalid array access at %s:%d.\n", filename.c_str(), linenum);
+		log_file_error(filename, linenum, "Invalid array access.\n");
 
 	return true;
 }
@@ -2976,6 +3155,39 @@ bool AstNode::mem2reg_as_needed_pass2(pool<AstNode*> &mem2reg_set, AstNode *mod,
 	if (type == AST_FUNCTION || type == AST_TASK)
 		return false;
 
+	if (type == AST_MEMINIT && id2ast && mem2reg_set.count(id2ast))
+	{
+		log_assert(children[0]->type == AST_CONSTANT);
+		log_assert(children[1]->type == AST_CONSTANT);
+		log_assert(children[2]->type == AST_CONSTANT);
+
+		int cursor = children[0]->asInt(false);
+		Const data = children[1]->bitsAsConst();
+		int length = children[2]->asInt(false);
+
+		if (length != 0)
+		{
+			AstNode *block = new AstNode(AST_INITIAL, new AstNode(AST_BLOCK));
+			mod->children.push_back(block);
+			block = block->children[0];
+
+			int wordsz = GetSize(data) / length;
+
+			for (int i = 0; i < length; i++) {
+				block->children.push_back(new AstNode(AST_ASSIGN_EQ, new AstNode(AST_IDENTIFIER, new AstNode(AST_RANGE, AstNode::mkconst_int(cursor+i, false))), mkconst_bits(data.extract(i*wordsz, wordsz).bits, false)));
+				block->children.back()->children[0]->str = str;
+				block->children.back()->children[0]->id2ast = id2ast;
+				block->children.back()->children[0]->was_checked = true;
+			}
+		}
+
+		AstNode *newNode = new AstNode(AST_NONE);
+		newNode->cloneInto(this);
+		delete newNode;
+
+		did_something = true;
+	}
+
 	if (type == AST_ASSIGN && block == NULL && children[0]->mem2reg_check(mem2reg_set))
 	{
 		if (async_block == NULL) {
@@ -2985,6 +3197,7 @@ bool AstNode::mem2reg_as_needed_pass2(pool<AstNode*> &mem2reg_set, AstNode *mod,
 
 		AstNode *newNode = clone();
 		newNode->type = AST_ASSIGN_EQ;
+		newNode->children[0]->was_checked = true;
 		async_block->children[0]->children.push_back(newNode);
 
 		newNode = new AstNode(AST_NONE);
@@ -3008,6 +3221,7 @@ bool AstNode::mem2reg_as_needed_pass2(pool<AstNode*> &mem2reg_set, AstNode *mod,
 		AstNode *wire_addr = new AstNode(AST_WIRE, new AstNode(AST_RANGE, mkconst_int(addr_bits-1, true), mkconst_int(0, true)));
 		wire_addr->str = id_addr;
 		wire_addr->is_reg = true;
+		wire_addr->was_checked = true;
 		wire_addr->attributes["\\nosync"] = AstNode::mkconst_int(1, false);
 		mod->children.push_back(wire_addr);
 		while (wire_addr->simplify(true, false, false, 1, -1, false, false)) { }
@@ -3015,6 +3229,7 @@ bool AstNode::mem2reg_as_needed_pass2(pool<AstNode*> &mem2reg_set, AstNode *mod,
 		AstNode *wire_data = new AstNode(AST_WIRE, new AstNode(AST_RANGE, mkconst_int(mem_width-1, true), mkconst_int(0, true)));
 		wire_data->str = id_data;
 		wire_data->is_reg = true;
+		wire_data->was_checked = true;
 		wire_data->is_signed = mem_signed;
 		wire_data->attributes["\\nosync"] = AstNode::mkconst_int(1, false);
 		mod->children.push_back(wire_data);
@@ -3028,6 +3243,7 @@ bool AstNode::mem2reg_as_needed_pass2(pool<AstNode*> &mem2reg_set, AstNode *mod,
 
 		AstNode *assign_addr = new AstNode(AST_ASSIGN_EQ, new AstNode(AST_IDENTIFIER), children[0]->children[0]->children[0]->clone());
 		assign_addr->children[0]->str = id_addr;
+		assign_addr->children[0]->was_checked = true;
 		block->children.insert(block->children.begin()+assign_idx+1, assign_addr);
 
 		AstNode *case_node = new AstNode(AST_CASE, new AstNode(AST_IDENTIFIER));
@@ -3051,6 +3267,7 @@ bool AstNode::mem2reg_as_needed_pass2(pool<AstNode*> &mem2reg_set, AstNode *mod,
 		children[0]->id2ast = NULL;
 		children[0]->str = id_data;
 		type = AST_ASSIGN_EQ;
+		children[0]->was_checked = true;
 
 		did_something = true;
 	}
@@ -3083,6 +3300,7 @@ bool AstNode::mem2reg_as_needed_pass2(pool<AstNode*> &mem2reg_set, AstNode *mod,
 			AstNode *wire_addr = new AstNode(AST_WIRE, new AstNode(AST_RANGE, mkconst_int(addr_bits-1, true), mkconst_int(0, true)));
 			wire_addr->str = id_addr;
 			wire_addr->is_reg = true;
+			wire_addr->was_checked = true;
 			if (block)
 				wire_addr->attributes["\\nosync"] = AstNode::mkconst_int(1, false);
 			mod->children.push_back(wire_addr);
@@ -3091,6 +3309,7 @@ bool AstNode::mem2reg_as_needed_pass2(pool<AstNode*> &mem2reg_set, AstNode *mod,
 			AstNode *wire_data = new AstNode(AST_WIRE, new AstNode(AST_RANGE, mkconst_int(mem_width-1, true), mkconst_int(0, true)));
 			wire_data->str = id_data;
 			wire_data->is_reg = true;
+			wire_data->was_checked = true;
 			wire_data->is_signed = mem_signed;
 			if (block)
 				wire_data->attributes["\\nosync"] = AstNode::mkconst_int(1, false);
@@ -3099,6 +3318,7 @@ bool AstNode::mem2reg_as_needed_pass2(pool<AstNode*> &mem2reg_set, AstNode *mod,
 
 			AstNode *assign_addr = new AstNode(block ? AST_ASSIGN_EQ : AST_ASSIGN, new AstNode(AST_IDENTIFIER), children[0]->children[0]->clone());
 			assign_addr->children[0]->str = id_addr;
+			assign_addr->children[0]->was_checked = true;
 
 			AstNode *case_node = new AstNode(AST_CASE, new AstNode(AST_IDENTIFIER));
 			case_node->children[0]->str = id_addr;
@@ -3109,6 +3329,7 @@ bool AstNode::mem2reg_as_needed_pass2(pool<AstNode*> &mem2reg_set, AstNode *mod,
 				AstNode *cond_node = new AstNode(AST_COND, AstNode::mkconst_int(i, false, addr_bits), new AstNode(AST_BLOCK));
 				AstNode *assign_reg = new AstNode(AST_ASSIGN_EQ, new AstNode(AST_IDENTIFIER), new AstNode(AST_IDENTIFIER));
 				assign_reg->children[0]->str = id_data;
+				assign_reg->children[0]->was_checked = true;
 				assign_reg->children[1]->str = stringf("%s[%d]", str.c_str(), i);
 				cond_node->children[1]->children.push_back(assign_reg);
 				case_node->children.push_back(cond_node);
@@ -3121,6 +3342,7 @@ bool AstNode::mem2reg_as_needed_pass2(pool<AstNode*> &mem2reg_set, AstNode *mod,
 			AstNode *cond_node = new AstNode(AST_COND, new AstNode(AST_DEFAULT), new AstNode(AST_BLOCK));
 			AstNode *assign_reg = new AstNode(AST_ASSIGN_EQ, new AstNode(AST_IDENTIFIER), AstNode::mkconst_bits(x_bits, false));
 			assign_reg->children[0]->str = id_data;
+			assign_reg->children[0]->was_checked = true;
 			cond_node->children[1]->children.push_back(assign_reg);
 			case_node->children.push_back(cond_node);
 
@@ -3195,6 +3417,16 @@ bool AstNode::has_const_only_constructs(bool &recommend_const_eval)
 	return false;
 }
 
+bool AstNode::is_simple_const_expr()
+{
+	if (type == AST_IDENTIFIER)
+		return false;
+	for (auto child : children)
+		if (!child->is_simple_const_expr())
+			return false;
+	return true;
+}
+
 // helper function for AstNode::eval_const_function()
 void AstNode::replace_variables(std::map<std::string, AstNode::varinfo_t> &variables, AstNode *fcall)
 {
@@ -3202,13 +3434,13 @@ void AstNode::replace_variables(std::map<std::string, AstNode::varinfo_t> &varia
 		int offset = variables.at(str).offset, width = variables.at(str).val.bits.size();
 		if (!children.empty()) {
 			if (children.size() != 1 || children.at(0)->type != AST_RANGE)
-				log_error("Memory access in constant function is not supported in %s:%d (called from %s:%d).\n",
-						filename.c_str(), linenum, fcall->filename.c_str(), fcall->linenum);
+				log_file_error(filename, linenum, "Memory access in constant function is not supported\n%s:%d: ...called from here.\n",
+						fcall->filename.c_str(), fcall->linenum);
 			children.at(0)->replace_variables(variables, fcall);
 			while (simplify(true, false, false, 1, -1, false, true)) { }
 			if (!children.at(0)->range_valid)
-				log_error("Non-constant range in %s:%d (called from %s:%d).\n",
-						filename.c_str(), linenum, fcall->filename.c_str(), fcall->linenum);
+				log_file_error(filename, linenum, "Non-constant range\n%s:%d: ... called from here.\n",
+						fcall->filename.c_str(), fcall->linenum);
 			offset = min(children.at(0)->range_left, children.at(0)->range_right);
 			width = min(std::abs(children.at(0)->range_left - children.at(0)->range_right) + 1, width);
 		}
@@ -3230,25 +3462,17 @@ AstNode *AstNode::eval_const_function(AstNode *fcall)
 {
 	std::map<std::string, AstNode*> backup_scope;
 	std::map<std::string, AstNode::varinfo_t> variables;
-	bool delete_temp_block = false;
-	AstNode *block = NULL;
+	AstNode *block = new AstNode(AST_BLOCK);
 
 	size_t argidx = 0;
 	for (auto child : children)
 	{
-		if (child->type == AST_BLOCK)
-		{
-			log_assert(block == NULL);
-			block = child;
-			continue;
-		}
-
 		if (child->type == AST_WIRE)
 		{
 			while (child->simplify(true, false, false, 1, -1, false, true)) { }
 			if (!child->range_valid)
-				log_error("Can't determine size of variable %s in %s:%d (called from %s:%d).\n",
-						child->str.c_str(), child->filename.c_str(), child->linenum, fcall->filename.c_str(), fcall->linenum);
+				log_file_error(child->filename, child->linenum, "Can't determine size of variable %s\n%s:%d: ... called from here.\n",
+						child->str.c_str(), fcall->filename.c_str(), fcall->linenum);
 			variables[child->str].val = RTLIL::Const(RTLIL::State::Sx, abs(child->range_left - child->range_right)+1);
 			variables[child->str].offset = min(child->range_left, child->range_right);
 			variables[child->str].is_signed = child->is_signed;
@@ -3259,13 +3483,9 @@ AstNode *AstNode::eval_const_function(AstNode *fcall)
 			continue;
 		}
 
-		log_assert(block == NULL);
-		delete_temp_block = true;
-		block = new AstNode(AST_BLOCK);
 		block->children.push_back(child->clone());
 	}
 
-	log_assert(block != NULL);
 	log_assert(variables.count(str) != 0);
 
 	while (!block->children.empty())
@@ -3291,24 +3511,24 @@ AstNode *AstNode::eval_const_function(AstNode *fcall)
 				continue;
 
 			if (stmt->children.at(1)->type != AST_CONSTANT)
-				log_error("Non-constant expression in constant function at %s:%d (called from %s:%d). X\n",
-						stmt->filename.c_str(), stmt->linenum, fcall->filename.c_str(), fcall->linenum);
+				log_file_error(stmt->filename, stmt->linenum, "Non-constant expression in constant function\n%s:%d: ... called from here. X\n",
+						fcall->filename.c_str(), fcall->linenum);
 
 			if (stmt->children.at(0)->type != AST_IDENTIFIER)
-				log_error("Unsupported composite left hand side in constant function at %s:%d (called from %s:%d).\n",
-						stmt->filename.c_str(), stmt->linenum, fcall->filename.c_str(), fcall->linenum);
+				log_file_error(stmt->filename, stmt->linenum, "Unsupported composite left hand side in constant function\n%s:%d: ... called from here.\n",
+						fcall->filename.c_str(), fcall->linenum);
 
 			if (!variables.count(stmt->children.at(0)->str))
-				log_error("Assignment to non-local variable in constant function at %s:%d (called from %s:%d).\n",
-						stmt->filename.c_str(), stmt->linenum, fcall->filename.c_str(), fcall->linenum);
+				log_file_error(stmt->filename, stmt->linenum, "Assignment to non-local variable in constant function\n%s:%d: ... called from here.\n",
+						fcall->filename.c_str(), fcall->linenum);
 
 			if (stmt->children.at(0)->children.empty()) {
 				variables[stmt->children.at(0)->str].val = stmt->children.at(1)->bitsAsConst(variables[stmt->children.at(0)->str].val.bits.size());
 			} else {
 				AstNode *range = stmt->children.at(0)->children.at(0);
 				if (!range->range_valid)
-					log_error("Non-constant range in %s:%d (called from %s:%d).\n",
-							range->filename.c_str(), range->linenum, fcall->filename.c_str(), fcall->linenum);
+					log_file_error(range->filename, range->linenum, "Non-constant range\n%s:%d: ... called from here.\n",
+							fcall->filename.c_str(), fcall->linenum);
 				int offset = min(range->range_left, range->range_right);
 				int width = std::abs(range->range_left - range->range_right) + 1;
 				varinfo_t &v = variables[stmt->children.at(0)->str];
@@ -3339,8 +3559,8 @@ AstNode *AstNode::eval_const_function(AstNode *fcall)
 			while (cond->simplify(true, false, false, 1, -1, false, true)) { }
 
 			if (cond->type != AST_CONSTANT)
-				log_error("Non-constant expression in constant function at %s:%d (called from %s:%d).\n",
-						stmt->filename.c_str(), stmt->linenum, fcall->filename.c_str(), fcall->linenum);
+				log_file_error(stmt->filename, stmt->linenum, "Non-constant expression in constant function\n%s:%d: ... called from here.\n",
+						fcall->filename.c_str(), fcall->linenum);
 
 			if (cond->asBool()) {
 				block->children.insert(block->children.begin(), stmt->children.at(1)->clone());
@@ -3360,8 +3580,8 @@ AstNode *AstNode::eval_const_function(AstNode *fcall)
 			while (num->simplify(true, false, false, 1, -1, false, true)) { }
 
 			if (num->type != AST_CONSTANT)
-				log_error("Non-constant expression in constant function at %s:%d (called from %s:%d).\n",
-						stmt->filename.c_str(), stmt->linenum, fcall->filename.c_str(), fcall->linenum);
+				log_file_error(stmt->filename, stmt->linenum, "Non-constant expression in constant function\n%s:%d: ... called from here.\n",
+						fcall->filename.c_str(), fcall->linenum);
 
 			block->children.erase(block->children.begin());
 			for (int i = 0; i < num->bitsAsConst().as_int(); i++)
@@ -3398,8 +3618,8 @@ AstNode *AstNode::eval_const_function(AstNode *fcall)
 					while (cond->simplify(true, false, false, 1, -1, false, true)) { }
 
 					if (cond->type != AST_CONSTANT)
-						log_error("Non-constant expression in constant function at %s:%d (called from %s:%d).\n",
-								stmt->filename.c_str(), stmt->linenum, fcall->filename.c_str(), fcall->linenum);
+						log_file_error(stmt->filename, stmt->linenum, "Non-constant expression in constant function\n%s:%d: ... called from here.\n",
+								fcall->filename.c_str(), fcall->linenum);
 
 					found_match = cond->asBool();
 					delete cond;
@@ -3428,13 +3648,12 @@ AstNode *AstNode::eval_const_function(AstNode *fcall)
 			continue;
 		}
 
-		log_error("Unsupported language construct in constant function at %s:%d (called from %s:%d).\n",
-				stmt->filename.c_str(), stmt->linenum, fcall->filename.c_str(), fcall->linenum);
+		log_file_error(stmt->filename, stmt->linenum, "Unsupported language construct in constant function\n%s:%d: ... called from here.\n",
+				fcall->filename.c_str(), fcall->linenum);
 		log_abort();
 	}
 
-	if (delete_temp_block)
-		delete block;
+	delete block;
 
 	for (auto &it : backup_scope)
 		if (it.second == NULL)
@@ -3446,4 +3665,3 @@ AstNode *AstNode::eval_const_function(AstNode *fcall)
 }
 
 YOSYS_NAMESPACE_END
-
diff --git a/frontends/blif/blifparse.cc b/frontends/blif/blifparse.cc
index e6bb99954..d17cacf29 100644
--- a/frontends/blif/blifparse.cc
+++ b/frontends/blif/blifparse.cc
@@ -78,12 +78,14 @@ failed:
 	return std::pair<RTLIL::IdString, int>("\\" + name, 0);
 }
 
-void parse_blif(RTLIL::Design *design, std::istream &f, std::string dff_name, bool run_clean, bool sop_mode, bool wideports)
+void parse_blif(RTLIL::Design *design, std::istream &f, IdString dff_name, bool run_clean, bool sop_mode, bool wideports)
 {
 	RTLIL::Module *module = nullptr;
 	RTLIL::Const *lutptr = NULL;
 	RTLIL::Cell *sopcell = NULL;
+	RTLIL::Cell *lastcell = nullptr;
 	RTLIL::State lut_default_state = RTLIL::State::Sx;
+	std::string err_reason;
 	int blif_maxnum = 0, sopmode = -1;
 
 	auto blif_wire = [&](const std::string &wire_name) -> Wire*
@@ -159,6 +161,7 @@ void parse_blif(RTLIL::Design *design, std::istream &f, std::string dff_name, bo
 				if (module != nullptr)
 					goto error;
 				module = new RTLIL::Module;
+				lastcell = nullptr;
 				module->name = RTLIL::escape_id(strtok(NULL, " \t\r\n"));
 				obj_attributes = &module->attributes;
 				obj_parameters = nullptr;
@@ -232,6 +235,7 @@ void parse_blif(RTLIL::Design *design, std::istream &f, std::string dff_name, bo
 				}
 
 				module = nullptr;
+				lastcell = nullptr;
 				obj_attributes = nullptr;
 				obj_parameters = nullptr;
 				continue;
@@ -264,6 +268,22 @@ void parse_blif(RTLIL::Design *design, std::istream &f, std::string dff_name, bo
 				continue;
 			}
 
+			if (!strcmp(cmd, ".cname"))
+			{
+				char *p = strtok(NULL, " \t\r\n");
+				if (p == NULL)
+					goto error;
+
+				if(lastcell == nullptr || module == nullptr)
+				{
+					err_reason = stringf("No primitive object to attach .cname %s.", p);
+					goto error_with_reason;
+				}
+
+				module->rename(lastcell, p);
+				continue;
+			}
+
 			if (!strcmp(cmd, ".attr") || !strcmp(cmd, ".param")) {
 				char *n = strtok(NULL, " \t\r\n");
 				char *v = strtok(NULL, "\r\n");
@@ -281,12 +301,16 @@ void parse_blif(RTLIL::Design *design, std::istream &f, std::string dff_name, bo
 						const_v.bits[i] = v[n-i-1] != '0' ? State::S1 : State::S0;
 				}
 				if (!strcmp(cmd, ".attr")) {
-					if (obj_attributes == nullptr)
-						goto error;
+					if (obj_attributes == nullptr) {
+						err_reason = stringf("No object to attach .attr too.");
+						goto error_with_reason;
+					}
 					(*obj_attributes)[id_n] = const_v;
 				} else {
-					if (obj_parameters == nullptr)
-						goto error;
+					if (obj_parameters == nullptr) {
+						err_reason = stringf("No object to attach .param too.");
+						goto error_with_reason;
+					}
 					(*obj_parameters)[id_n] = const_v;
 				}
 				continue;
@@ -331,6 +355,7 @@ void parse_blif(RTLIL::Design *design, std::istream &f, std::string dff_name, bo
 					}
 				}
 
+				lastcell = cell;
 				obj_attributes = &cell->attributes;
 				obj_parameters = &cell->parameters;
 				continue;
@@ -383,6 +408,7 @@ void parse_blif(RTLIL::Design *design, std::istream &f, std::string dff_name, bo
 					cell->setPort(it.first, sig);
 				}
 
+				lastcell = cell;
 				obj_attributes = &cell->attributes;
 				obj_parameters = &cell->parameters;
 				continue;
@@ -391,7 +417,7 @@ void parse_blif(RTLIL::Design *design, std::istream &f, std::string dff_name, bo
 			obj_attributes = nullptr;
 			obj_parameters = nullptr;
 
-			if (!strcmp(cmd, ".barbuf"))
+			if (!strcmp(cmd, ".barbuf") || !strcmp(cmd, ".conn"))
 			{
 				char *p = strtok(NULL, " \t\r\n");
 				if (p == NULL)
@@ -459,6 +485,7 @@ void parse_blif(RTLIL::Design *design, std::istream &f, std::string dff_name, bo
 					sopcell->setPort("\\A", input_sig);
 					sopcell->setPort("\\Y", output_sig);
 					sopmode = -1;
+					lastcell = sopcell;
 				}
 				else
 				{
@@ -469,6 +496,7 @@ void parse_blif(RTLIL::Design *design, std::istream &f, std::string dff_name, bo
 					cell->setPort("\\Y", output_sig);
 					lutptr = &cell->parameters.at("\\LUT");
 					lut_default_state = RTLIL::State::Sx;
+					lastcell = cell;
 				}
 				continue;
 			}
@@ -546,15 +574,17 @@ void parse_blif(RTLIL::Design *design, std::istream &f, std::string dff_name, bo
 
 error:
 	log_error("Syntax error in line %d!\n", line_count);
+error_with_reason:
+	log_error("Syntax error in line %d: %s\n", line_count, err_reason.c_str());
 }
 
 struct BlifFrontend : public Frontend {
 	BlifFrontend() : Frontend("blif", "read BLIF file") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
-		log("    read_blif [filename]\n");
+		log("    read_blif [options] [filename]\n");
 		log("\n");
 		log("Load modules from a BLIF file into the current design.\n");
 		log("\n");
@@ -566,7 +596,7 @@ struct BlifFrontend : public Frontend {
 		log("        multi-bit port 'name'.\n");
 		log("\n");
 	}
-	virtual void execute(std::istream *&f, std::string filename, std::vector<std::string> args, RTLIL::Design *design)
+	void execute(std::istream *&f, std::string filename, std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
 	{
 		bool sop_mode = false;
 		bool wideports = false;
diff --git a/frontends/blif/blifparse.h b/frontends/blif/blifparse.h
index 955b6aacf..2b84cb795 100644
--- a/frontends/blif/blifparse.h
+++ b/frontends/blif/blifparse.h
@@ -24,7 +24,7 @@
 
 YOSYS_NAMESPACE_BEGIN
 
-extern void parse_blif(RTLIL::Design *design, std::istream &f, std::string dff_name,
+extern void parse_blif(RTLIL::Design *design, std::istream &f, IdString dff_name,
 		bool run_clean = false, bool sop_mode = false, bool wideports = false);
 
 YOSYS_NAMESPACE_END
diff --git a/frontends/ilang/.gitignore b/frontends/ilang/.gitignore
index 43106a814..f586b33c7 100644
--- a/frontends/ilang/.gitignore
+++ b/frontends/ilang/.gitignore
@@ -1,4 +1,4 @@
 ilang_lexer.cc
 ilang_parser.output
 ilang_parser.tab.cc
-ilang_parser.tab.h
+ilang_parser.tab.hh
diff --git a/frontends/ilang/Makefile.inc b/frontends/ilang/Makefile.inc
index e2a476c93..6f1f0e8fc 100644
--- a/frontends/ilang/Makefile.inc
+++ b/frontends/ilang/Makefile.inc
@@ -1,15 +1,14 @@
 
 GENFILES += frontends/ilang/ilang_parser.tab.cc
-GENFILES += frontends/ilang/ilang_parser.tab.h
+GENFILES += frontends/ilang/ilang_parser.tab.hh
 GENFILES += frontends/ilang/ilang_parser.output
 GENFILES += frontends/ilang/ilang_lexer.cc
 
 frontends/ilang/ilang_parser.tab.cc: frontends/ilang/ilang_parser.y
 	$(Q) mkdir -p $(dir $@)
-	$(P) $(BISON) -d -r all -b frontends/ilang/ilang_parser $<
-	$(Q) mv frontends/ilang/ilang_parser.tab.c frontends/ilang/ilang_parser.tab.cc
+	$(P) $(BISON) -o $@ -d -r all -b frontends/ilang/ilang_parser $<
 
-frontends/ilang/ilang_parser.tab.h: frontends/ilang/ilang_parser.tab.cc
+frontends/ilang/ilang_parser.tab.hh: frontends/ilang/ilang_parser.tab.cc
 
 frontends/ilang/ilang_lexer.cc: frontends/ilang/ilang_lexer.l
 	$(Q) mkdir -p $(dir $@)
diff --git a/frontends/ilang/ilang_frontend.cc b/frontends/ilang/ilang_frontend.cc
index ed6789987..30d9ff79d 100644
--- a/frontends/ilang/ilang_frontend.cc
+++ b/frontends/ilang/ilang_frontend.cc
@@ -35,7 +35,7 @@ YOSYS_NAMESPACE_BEGIN
 
 struct IlangFrontend : public Frontend {
 	IlangFrontend() : Frontend("ilang", "read modules from ilang file") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -44,11 +44,47 @@ struct IlangFrontend : public Frontend {
 		log("Load modules from an ilang file to the current design. (ilang is a text\n");
 		log("representation of a design in yosys's internal format.)\n");
 		log("\n");
+		log("    -nooverwrite\n");
+		log("        ignore re-definitions of modules. (the default behavior is to\n");
+		log("        create an error message if the existing module is not a blackbox\n");
+		log("        module, and overwrite the existing module if it is a blackbox module.)\n");
+		log("\n");
+		log("    -overwrite\n");
+		log("        overwrite existing modules with the same name\n");
+		log("\n");
+		log("    -lib\n");
+		log("        only create empty blackbox modules\n");
+		log("\n");
 	}
-	virtual void execute(std::istream *&f, std::string filename, std::vector<std::string> args, RTLIL::Design *design)
+	void execute(std::istream *&f, std::string filename, std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
 	{
+		ILANG_FRONTEND::flag_nooverwrite = false;
+		ILANG_FRONTEND::flag_overwrite = false;
+		ILANG_FRONTEND::flag_lib = false;
+
 		log_header(design, "Executing ILANG frontend.\n");
-		extra_args(f, filename, args, 1);
+
+		size_t argidx;
+		for (argidx = 1; argidx < args.size(); argidx++) {
+			std::string arg = args[argidx];
+			if (arg == "-nooverwrite") {
+				ILANG_FRONTEND::flag_nooverwrite = true;
+				ILANG_FRONTEND::flag_overwrite = false;
+				continue;
+			}
+			if (arg == "-overwrite") {
+				ILANG_FRONTEND::flag_nooverwrite = false;
+				ILANG_FRONTEND::flag_overwrite = true;
+				continue;
+			}
+			if (arg == "-lib") {
+				ILANG_FRONTEND::flag_lib = true;
+				continue;
+			}
+			break;
+		}
+		extra_args(f, filename, args, argidx);
+
 		log("Input filename: %s\n", filename.c_str());
 
 		ILANG_FRONTEND::lexin = f;
diff --git a/frontends/ilang/ilang_frontend.h b/frontends/ilang/ilang_frontend.h
index ad3ffec90..f8a152841 100644
--- a/frontends/ilang/ilang_frontend.h
+++ b/frontends/ilang/ilang_frontend.h
@@ -32,6 +32,9 @@ YOSYS_NAMESPACE_BEGIN
 namespace ILANG_FRONTEND {
 	extern std::istream *lexin;
 	extern RTLIL::Design *current_design;
+	extern bool flag_nooverwrite;
+	extern bool flag_overwrite;
+	extern bool flag_lib;
 }
 
 YOSYS_NAMESPACE_END
diff --git a/frontends/ilang/ilang_lexer.l b/frontends/ilang/ilang_lexer.l
index 842388548..4fd0ae855 100644
--- a/frontends/ilang/ilang_lexer.l
+++ b/frontends/ilang/ilang_lexer.l
@@ -30,7 +30,7 @@
 #endif
 
 #include "frontends/ilang/ilang_frontend.h"
-#include "ilang_parser.tab.h"
+#include "ilang_parser.tab.hh"
 
 USING_YOSYS_NAMESPACE
 
@@ -53,6 +53,7 @@ USING_YOSYS_NAMESPACE
 "attribute"	{ return TOK_ATTRIBUTE; }
 "parameter"	{ return TOK_PARAMETER; }
 "signed"	{ return TOK_SIGNED; }
+"real"		{ return TOK_REAL; }
 "wire"		{ return TOK_WIRE; }
 "memory"	{ return TOK_MEMORY; }
 "width"		{ return TOK_WIDTH; }
diff --git a/frontends/ilang/ilang_parser.y b/frontends/ilang/ilang_parser.y
index bfc062fec..b4b9693da 100644
--- a/frontends/ilang/ilang_parser.y
+++ b/frontends/ilang/ilang_parser.y
@@ -37,13 +37,24 @@ namespace ILANG_FRONTEND {
 	std::vector<std::vector<RTLIL::SwitchRule*>*> switch_stack;
 	std::vector<RTLIL::CaseRule*> case_stack;
 	dict<RTLIL::IdString, RTLIL::Const> attrbuf;
+	bool flag_nooverwrite, flag_overwrite, flag_lib;
+	bool delete_current_module;
 }
 using namespace ILANG_FRONTEND;
 YOSYS_NAMESPACE_END
 USING_YOSYS_NAMESPACE
 %}
 
-%name-prefix "rtlil_frontend_ilang_yy"
+%define api.prefix {rtlil_frontend_ilang_yy}
+
+/* The union is defined in the header, so we need to provide all the
+ * includes it requires
+ */
+%code requires {
+#include <string>
+#include <vector>
+#include "frontends/ilang/ilang_frontend.h"
+}
 
 %union {
 	char *string;
@@ -59,7 +70,7 @@ USING_YOSYS_NAMESPACE
 %token TOK_CELL TOK_CONNECT TOK_SWITCH TOK_CASE TOK_ASSIGN TOK_SYNC
 %token TOK_LOW TOK_HIGH TOK_POSEDGE TOK_NEGEDGE TOK_EDGE TOK_ALWAYS TOK_GLOBAL TOK_INIT
 %token TOK_UPDATE TOK_PROCESS TOK_END TOK_INVALID TOK_EOL TOK_OFFSET
-%token TOK_PARAMETER TOK_ATTRIBUTE TOK_MEMORY TOK_SIZE TOK_SIGNED TOK_UPTO
+%token TOK_PARAMETER TOK_ATTRIBUTE TOK_MEMORY TOK_SIZE TOK_SIGNED TOK_REAL TOK_UPTO
 
 %type <rsigspec> sigspec_list_reversed
 %type <sigspec> sigspec sigspec_list
@@ -93,18 +104,38 @@ design:
 
 module:
 	TOK_MODULE TOK_ID EOL {
-		if (current_design->has($2))
-			rtlil_frontend_ilang_yyerror(stringf("ilang error: redefinition of module %s.", $2).c_str());
+		delete_current_module = false;
+		if (current_design->has($2)) {
+			RTLIL::Module *existing_mod = current_design->module($2);
+			if (!flag_overwrite && (flag_lib || (attrbuf.count("\\blackbox") && attrbuf.at("\\blackbox").as_bool()))) {
+				log("Ignoring blackbox re-definition of module %s.\n", $2);
+				delete_current_module = true;
+			} else if (!flag_nooverwrite && !flag_overwrite && !existing_mod->get_bool_attribute("\\blackbox")) {
+				rtlil_frontend_ilang_yyerror(stringf("ilang error: redefinition of module %s.", $2).c_str());
+			} else if (flag_nooverwrite) {
+				log("Ignoring re-definition of module %s.\n", $2);
+				delete_current_module = true;
+			} else {
+				log("Replacing existing%s module %s.\n", existing_mod->get_bool_attribute("\\blackbox") ? " blackbox" : "", $2);
+				current_design->remove(existing_mod);
+			}
+		}
 		current_module = new RTLIL::Module;
 		current_module->name = $2;
 		current_module->attributes = attrbuf;
-		current_design->add(current_module);
+		if (!delete_current_module)
+			current_design->add(current_module);
 		attrbuf.clear();
 		free($2);
 	} module_body TOK_END {
 		if (attrbuf.size() != 0)
 			rtlil_frontend_ilang_yyerror("dangling attribute");
 		current_module->fixup_ports();
+		if (delete_current_module)
+			delete current_module;
+		else if (flag_lib)
+			current_module->makeblackbox();
+		current_module = nullptr;
 	} EOL;
 
 module_body:
@@ -219,6 +250,12 @@ cell_body:
 		free($4);
 		delete $5;
 	} |
+	cell_body TOK_PARAMETER TOK_REAL TOK_ID constant EOL {
+		current_cell->parameters[$4] = *$5;
+		current_cell->parameters[$4].flags |= RTLIL::CONST_FLAG_REAL;
+		free($4);
+		delete $5;
+	} |
 	cell_body TOK_CONNECT TOK_ID sigspec EOL {
 		if (current_cell->hasPort($3))
 			rtlil_frontend_ilang_yyerror(stringf("ilang error: redefinition of cell port %s.", $3).c_str());
@@ -245,14 +282,14 @@ proc_stmt:
 	} case_body sync_list TOK_END EOL;
 
 switch_stmt:
-	attr_list TOK_SWITCH sigspec EOL {
+	TOK_SWITCH sigspec EOL {
 		RTLIL::SwitchRule *rule = new RTLIL::SwitchRule;
-		rule->signal = *$3;
+		rule->signal = *$2;
 		rule->attributes = attrbuf;
 		switch_stack.back()->push_back(rule);
 		attrbuf.clear();
-		delete $3;
-	} switch_body TOK_END EOL;
+		delete $2;
+	} attr_list switch_body TOK_END EOL;
 
 attr_list:
 	/* empty */ |
@@ -261,9 +298,11 @@ attr_list:
 switch_body:
 	switch_body TOK_CASE {
 		RTLIL::CaseRule *rule = new RTLIL::CaseRule;
+		rule->attributes = attrbuf;
 		switch_stack.back()->back()->cases.push_back(rule);
 		switch_stack.push_back(&rule->switches);
 		case_stack.push_back(rule);
+		attrbuf.clear();
 	} compare_list EOL case_body {
 		switch_stack.pop_back();
 		case_stack.pop_back();
@@ -282,12 +321,15 @@ compare_list:
 	/* empty */;
 
 case_body:
+	case_body attr_stmt |
 	case_body switch_stmt |
 	case_body assign_stmt |
 	/* empty */;
 
 assign_stmt:
 	TOK_ASSIGN sigspec sigspec EOL {
+		if (attrbuf.size() != 0)
+			rtlil_frontend_ilang_yyerror("dangling attribute");
 		case_stack.back()->actions.push_back(RTLIL::SigSig(*$2, *$3));
 		delete $2;
 		delete $3;
@@ -387,17 +429,13 @@ sigspec:
 		$$ = new RTLIL::SigSpec(current_module->wires_[$1]);
 		free($1);
 	} |
-	TOK_ID '[' TOK_INT ']' {
-		if (current_module->wires_.count($1) == 0)
-			rtlil_frontend_ilang_yyerror(stringf("ilang error: wire %s not found", $1).c_str());
-		$$ = new RTLIL::SigSpec(current_module->wires_[$1], $3);
-		free($1);
+	sigspec '[' TOK_INT ']' {
+		$$ = new RTLIL::SigSpec($1->extract($3));
+		delete $1;
 	} |
-	TOK_ID '[' TOK_INT ':' TOK_INT ']' {
-		if (current_module->wires_.count($1) == 0)
-			rtlil_frontend_ilang_yyerror(stringf("ilang error: wire %s not found", $1).c_str());
-		$$ = new RTLIL::SigSpec(current_module->wires_[$1], $5, $3 - $5 + 1);
-		free($1);
+	sigspec '[' TOK_INT ':' TOK_INT ']' {
+		$$ = new RTLIL::SigSpec($1->extract($5, $3 - $5 + 1));
+		delete $1;
 	} |
 	'{' sigspec_list '}' {
 		$$ = $2;
@@ -427,4 +465,3 @@ conn_stmt:
 		delete $2;
 		delete $3;
 	};
-
diff --git a/frontends/json/jsonparse.cc b/frontends/json/jsonparse.cc
index 629578c61..7aceffbfc 100644
--- a/frontends/json/jsonparse.cc
+++ b/frontends/json/jsonparse.cc
@@ -25,7 +25,7 @@ struct JsonNode
 {
 	char type; // S=String, N=Number, A=Array, D=Dict
 	string data_string;
-	int data_number;
+	int64_t data_number;
 	vector<JsonNode*> data_array;
 	dict<string, JsonNode*> data_dict;
 	vector<string> data_dict_keys;
@@ -206,6 +206,38 @@ struct JsonNode
 	}
 };
 
+Const json_parse_attr_param_value(JsonNode *node)
+{
+	Const value;
+
+	if (node->type == 'S') {
+		string &s = node->data_string;
+		size_t cursor = s.find_first_not_of("01xz");
+		if (cursor == string::npos) {
+			value = Const::from_string(s);
+		} else if (s.find_first_not_of(' ', cursor) == string::npos) {
+			value = Const(s.substr(0, GetSize(s)-1));
+		} else {
+			value = Const(s);
+		}
+	} else
+	if (node->type == 'N') {
+		value = Const(node->data_number, 32);
+		if (node->data_number < 0)
+			value.flags |= RTLIL::CONST_FLAG_SIGNED;
+	} else
+	if (node->type == 'A') {
+		log_error("JSON attribute or parameter value is an array.\n");
+	} else
+	if (node->type == 'D') {
+		log_error("JSON attribute or parameter value is a dict.\n");
+	} else {
+		log_abort();
+	}
+
+	return value;
+}
+
 void json_parse_attr_param(dict<IdString, Const> &results, JsonNode *node)
 {
 	if (node->type != 'D')
@@ -214,28 +246,7 @@ void json_parse_attr_param(dict<IdString, Const> &results, JsonNode *node)
 	for (auto it : node->data_dict)
 	{
 		IdString key = RTLIL::escape_id(it.first.c_str());
-		JsonNode *value_node = it.second;
-		Const value;
-
-		if (value_node->type == 'S') {
-			string &s = value_node->data_string;
-			if (s.find_first_not_of("01xz") == string::npos)
-				value = Const::from_string(s);
-			else
-				value = Const(s);
-		} else
-		if (value_node->type == 'N') {
-			value = Const(value_node->data_number, 32);
-		} else
-		if (value_node->type == 'A') {
-			log_error("JSON attribute or parameter value is an array.\n");
-		} else
-		if (value_node->type == 'D') {
-			log_error("JSON attribute or parameter value is a dict.\n");
-		} else {
-			log_abort();
-		}
-
+		Const value = json_parse_attr_param_value(it.second);
 		results[key] = value;
 	}
 }
@@ -292,6 +303,18 @@ void json_import(Design *design, string &modname, JsonNode *node)
 			if (port_wire == nullptr)
 				port_wire = module->addWire(port_name, GetSize(port_bits_node->data_array));
 
+			if (port_node->data_dict.count("upto") != 0) {
+				JsonNode *val = port_node->data_dict.at("upto");
+				if (val->type == 'N')
+					port_wire->upto = val->data_number != 0;
+			}
+
+			if (port_node->data_dict.count("offset") != 0) {
+				JsonNode *val = port_node->data_dict.at("offset");
+				if (val->type == 'N')
+					port_wire->start_offset = val->data_number;
+			}
+
 			if (port_direction_node->data_string == "input") {
 				port_wire->port_input = true;
 			} else
@@ -372,6 +395,18 @@ void json_import(Design *design, string &modname, JsonNode *node)
 			if (wire == nullptr)
 				wire = module->addWire(net_name, GetSize(bits_node->data_array));
 
+			if (net_node->data_dict.count("upto") != 0) {
+				JsonNode *val = net_node->data_dict.at("upto");
+				if (val->type == 'N')
+					wire->upto = val->data_number != 0;
+			}
+
+			if (net_node->data_dict.count("offset") != 0) {
+				JsonNode *val = net_node->data_dict.at("offset");
+				if (val->type == 'N')
+					wire->start_offset = val->data_number;
+			}
+
 			for (int i = 0; i < GetSize(bits_node->data_array); i++)
 			{
 				JsonNode *bitval_node = bits_node->data_array.at(i);
@@ -494,7 +529,7 @@ void json_import(Design *design, string &modname, JsonNode *node)
 
 struct JsonFrontend : public Frontend {
 	JsonFrontend() : Frontend("json", "read JSON file") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -504,7 +539,7 @@ struct JsonFrontend : public Frontend {
 		log("for a description of the file format.\n");
 		log("\n");
 	}
-	virtual void execute(std::istream *&f, std::string filename, std::vector<std::string> args, RTLIL::Design *design)
+	void execute(std::istream *&f, std::string filename, std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
 	{
 		log_header(design, "Executing JSON frontend.\n");
 
diff --git a/frontends/liberty/liberty.cc b/frontends/liberty/liberty.cc
index b9e53a4be..14de95e07 100644
--- a/frontends/liberty/liberty.cc
+++ b/frontends/liberty/liberty.cc
@@ -36,7 +36,8 @@ static RTLIL::SigSpec parse_func_identifier(RTLIL::Module *module, const char *&
 
 	int id_len = 0;
 	while (('a' <= expr[id_len] && expr[id_len] <= 'z') || ('A' <= expr[id_len] && expr[id_len] <= 'Z') ||
-			('0' <= expr[id_len] && expr[id_len] <= '9') || expr[id_len] == '.' || expr[id_len] == '_') id_len++;
+			('0' <= expr[id_len] && expr[id_len] <= '9') || expr[id_len] == '.' ||
+			expr[id_len] == '_' || expr[id_len] == '[' || expr[id_len] == ']') id_len++;
 
 	if (id_len == 0)
 		log_error("Expected identifier at `%s'.\n", expr);
@@ -452,7 +453,7 @@ void parse_type_map(std::map<std::string, std::tuple<int, int, bool>> &type_map,
 
 struct LibertyFrontend : public Frontend {
 	LibertyFrontend() : Frontend("liberty", "read cells from liberty file") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -485,7 +486,7 @@ struct LibertyFrontend : public Frontend {
 		log("        set the specified attribute (to the value 1) on all loaded modules\n");
 		log("\n");
 	}
-	virtual void execute(std::istream *&f, std::string filename, std::vector<std::string> args, RTLIL::Design *design)
+	void execute(std::istream *&f, std::string filename, std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
 	{
 		bool flag_lib = false;
 		bool flag_nooverwrite = false;
@@ -550,7 +551,7 @@ struct LibertyFrontend : public Frontend {
 			if (design->has(cell_name)) {
 				Module *existing_mod = design->module(cell_name);
 				if (!flag_nooverwrite && !flag_overwrite && !existing_mod->get_bool_attribute("\\blackbox")) {
-					log_error("Re-definition of of cell/module %s!\n", log_id(cell_name));
+					log_error("Re-definition of cell/module %s!\n", log_id(cell_name));
 				} else if (flag_nooverwrite) {
 					log("Ignoring re-definition of module %s.\n", log_id(cell_name));
 					continue;
@@ -615,7 +616,7 @@ struct LibertyFrontend : public Frontend {
 					LibertyAst *bus_type_node = node->find("bus_type");
 
 					if (!bus_type_node || !type_map.count(bus_type_node->value))
-						log_error("Unkown or unsupported type for bus interface %s on cell %s.\n",
+						log_error("Unknown or unsupported type for bus interface %s on cell %s.\n",
 								node->args.at(0).c_str(), log_id(cell_name));
 
 					int bus_type_width = std::get<0>(type_map.at(bus_type_node->value));
@@ -634,9 +635,12 @@ struct LibertyFrontend : public Frontend {
 				}
 			}
 
-			for (auto node : cell->children)
+			if (!flag_lib)
 			{
-				if (!flag_lib) {
+				// some liberty files do not put ff/latch at the beginning of a cell
+				// try to find "ff" or "latch" and create FF/latch _before_ processing all other nodes
+				for (auto node : cell->children)
+				{
 					if (node->id == "ff" && node->args.size() == 2)
 						create_ff(module, node);
 					if (node->id == "latch" && node->args.size() == 2)
@@ -645,7 +649,10 @@ struct LibertyFrontend : public Frontend {
 							goto skip_cell;
 						}
 				}
+			}
 
+			for (auto node : cell->children)
+			{
 				if (node->id == "pin" && node->args.size() == 1)
 				{
 					LibertyAst *dir = node->find("direction");
diff --git a/frontends/verific/README b/frontends/verific/README
index b4c436a3a..89584f2e8 100644
--- a/frontends/verific/README
+++ b/frontends/verific/README
@@ -4,35 +4,6 @@ This directory contains Verific bindings for Yosys.
 See http://www.verific.com/ for details.
 
 
-Building Yosys with the 32 bit Verific eval library on amd64:
-=============================================================
-
-1.) Use a Makefile.conf like the following one:
-
---snip--
-CONFIG := gcc
-ENABLE_TCL := 0
-ENABLE_PLUGINS := 0
-ENABLE_VERIFIC := 1
-CXXFLAGS += -m32
-LDFLAGS += -m32
-VERIFIC_DIR = /usr/local/src/verific_lib_eval
---snap--
-
-
-2.) Install the necessary multilib packages
-
-Hint: On debian/ubuntu the multilib packages have names such as
-libreadline-dev:i386 or lib32readline6-dev, depending on the
-exact version of debian/ubuntu you are working with.
-
-
-3.) Build and test
-
-make -j8
-./yosys -p 'verific -sv frontends/verific/example.sv; verific -import top'
-
-
 Verific Features that should be enabled in your Verific library
 ===============================================================
 
@@ -50,7 +21,7 @@ Then run in the following command in this directory:
 
 	sby -f example.sby
 
-This will generate approximately one page of text outpout. The last lines
+This will generate approximately one page of text output. The last lines
 should be something like this:
 
 	SBY [example] summary: Elapsed clock time [H:MM:SS (secs)]: 0:00:00 (0)
diff --git a/frontends/verific/verific.cc b/frontends/verific/verific.cc
index 62a8028b8..c5eef4b55 100644
--- a/frontends/verific/verific.cc
+++ b/frontends/verific/verific.cc
@@ -19,6 +19,7 @@
 
 #include "kernel/yosys.h"
 #include "kernel/sigtools.h"
+#include "kernel/celltypes.h"
 #include "kernel/log.h"
 #include <stdlib.h>
 #include <stdio.h>
@@ -46,7 +47,15 @@ USING_YOSYS_NAMESPACE
 #include "VeriModule.h"
 #include "VeriWrite.h"
 #include "VhdlUnits.h"
-#include "Message.h"
+#include "VeriLibrary.h"
+
+#ifndef SYMBIOTIC_VERIFIC_API_VERSION
+#  error "Only Symbiotic EDA flavored Verific is supported. Please contact office@symbioticeda.com for commercial support for Yosys+Verific."
+#endif
+
+#if SYMBIOTIC_VERIFIC_API_VERSION < 1
+#  error "Please update your version of Symbiotic EDA flavored Verific."
+#endif
 
 #ifdef __clang__
 #pragma clang diagnostic pop
@@ -64,6 +73,9 @@ YOSYS_NAMESPACE_BEGIN
 int verific_verbose;
 bool verific_import_pending;
 string verific_error_msg;
+int verific_sva_fsm_limit;
+
+vector<string> verific_incdirs, verific_libdirs;
 
 void msg_func(msg_type_t msg_type, const char *message_id, linefile_type linefile, const char *msg, va_list args)
 {
@@ -100,9 +112,10 @@ string get_full_netlist_name(Netlist *nl)
 
 // ==================================================================
 
-VerificImporter::VerificImporter(bool mode_gates, bool mode_keep, bool mode_nosva, bool mode_names, bool mode_verific, bool mode_autocover) :
+VerificImporter::VerificImporter(bool mode_gates, bool mode_keep, bool mode_nosva, bool mode_names, bool mode_verific, bool mode_autocover, bool mode_fullinit) :
 		mode_gates(mode_gates), mode_keep(mode_keep), mode_nosva(mode_nosva),
-		mode_names(mode_names), mode_verific(mode_verific), mode_autocover(mode_autocover)
+		mode_names(mode_names), mode_verific(mode_verific), mode_autocover(mode_autocover),
+		mode_fullinit(mode_fullinit)
 {
 }
 
@@ -115,6 +128,27 @@ RTLIL::SigBit VerificImporter::net_map_at(Net *net)
 	return net_map.at(net);
 }
 
+bool is_blackbox(Netlist *nl)
+{
+	if (nl->IsBlackBox())
+		return true;
+
+	const char *attr = nl->GetAttValue("blackbox");
+	if (attr != nullptr && strcmp(attr, "0"))
+		return true;
+
+	return false;
+}
+
+RTLIL::IdString VerificImporter::new_verific_id(Verific::DesignObj *obj)
+{
+	std::string s = stringf("$verific$%s", obj->Name());
+	if (obj->Linefile())
+		s += stringf("$%s:%d", Verific::LineFile::GetFileName(obj->Linefile()), Verific::LineFile::GetLineNo(obj->Linefile()));
+	s += stringf("$%d", autoidx++);
+	return s;
+}
+
 void VerificImporter::import_attributes(dict<RTLIL::IdString, RTLIL::Const> &attributes, DesignObj *obj)
 {
 	MapIter mi;
@@ -200,7 +234,7 @@ RTLIL::SigSpec VerificImporter::operatorOutput(Instance *inst, const pool<Net*,
 			dummy_wire = NULL;
 		} else {
 			if (dummy_wire == NULL)
-				dummy_wire = module->addWire(NEW_ID);
+				dummy_wire = module->addWire(new_verific_id(inst));
 			else
 				dummy_wire->width++;
 			sig.append(RTLIL::SigSpec(dummy_wire, dummy_wire->width - 1));
@@ -216,8 +250,8 @@ bool VerificImporter::import_netlist_instance_gates(Instance *inst, RTLIL::IdStr
 	}
 
 	if (inst->Type() == PRIM_NAND) {
-		RTLIL::SigSpec tmp = module->addWire(NEW_ID);
-		module->addAndGate(NEW_ID, net_map_at(inst->GetInput1()), net_map_at(inst->GetInput2()), tmp);
+		RTLIL::SigSpec tmp = module->addWire(new_verific_id(inst));
+		module->addAndGate(new_verific_id(inst), net_map_at(inst->GetInput1()), net_map_at(inst->GetInput2()), tmp);
 		module->addNotGate(inst_name, tmp, net_map_at(inst->GetOutput()));
 		return true;
 	}
@@ -228,8 +262,8 @@ bool VerificImporter::import_netlist_instance_gates(Instance *inst, RTLIL::IdStr
 	}
 
 	if (inst->Type() == PRIM_NOR) {
-		RTLIL::SigSpec tmp = module->addWire(NEW_ID);
-		module->addOrGate(NEW_ID, net_map_at(inst->GetInput1()), net_map_at(inst->GetInput2()), tmp);
+		RTLIL::SigSpec tmp = module->addWire(new_verific_id(inst));
+		module->addOrGate(new_verific_id(inst), net_map_at(inst->GetInput1()), net_map_at(inst->GetInput2()), tmp);
 		module->addNotGate(inst_name, tmp, net_map_at(inst->GetOutput()));
 		return true;
 	}
@@ -269,16 +303,16 @@ bool VerificImporter::import_netlist_instance_gates(Instance *inst, RTLIL::IdStr
 	if (inst->Type() == PRIM_FADD)
 	{
 		RTLIL::SigSpec a = net_map_at(inst->GetInput1()), b = net_map_at(inst->GetInput2()), c = net_map_at(inst->GetCin());
-		RTLIL::SigSpec x = inst->GetCout() ? net_map_at(inst->GetCout()) : module->addWire(NEW_ID);
-		RTLIL::SigSpec y = inst->GetOutput() ? net_map_at(inst->GetOutput()) : module->addWire(NEW_ID);
-		RTLIL::SigSpec tmp1 = module->addWire(NEW_ID);
-		RTLIL::SigSpec tmp2 = module->addWire(NEW_ID);
-		RTLIL::SigSpec tmp3 = module->addWire(NEW_ID);
-		module->addXorGate(NEW_ID, a, b, tmp1);
+		RTLIL::SigSpec x = inst->GetCout() ? net_map_at(inst->GetCout()) : module->addWire(new_verific_id(inst));
+		RTLIL::SigSpec y = inst->GetOutput() ? net_map_at(inst->GetOutput()) : module->addWire(new_verific_id(inst));
+		RTLIL::SigSpec tmp1 = module->addWire(new_verific_id(inst));
+		RTLIL::SigSpec tmp2 = module->addWire(new_verific_id(inst));
+		RTLIL::SigSpec tmp3 = module->addWire(new_verific_id(inst));
+		module->addXorGate(new_verific_id(inst), a, b, tmp1);
 		module->addXorGate(inst_name, tmp1, c, y);
-		module->addAndGate(NEW_ID, tmp1, c, tmp2);
-		module->addAndGate(NEW_ID, a, b, tmp3);
-		module->addOrGate(NEW_ID, tmp2, tmp3, x);
+		module->addAndGate(new_verific_id(inst), tmp1, c, tmp2);
+		module->addAndGate(new_verific_id(inst), a, b, tmp3);
+		module->addOrGate(new_verific_id(inst), tmp2, tmp3, x);
 		return true;
 	}
 
@@ -305,63 +339,78 @@ bool VerificImporter::import_netlist_instance_gates(Instance *inst, RTLIL::IdStr
 
 bool VerificImporter::import_netlist_instance_cells(Instance *inst, RTLIL::IdString inst_name)
 {
+	RTLIL::Cell *cell = nullptr;
+
 	if (inst->Type() == PRIM_AND) {
-		module->addAnd(inst_name, net_map_at(inst->GetInput1()), net_map_at(inst->GetInput2()), net_map_at(inst->GetOutput()));
+		cell = module->addAnd(inst_name, net_map_at(inst->GetInput1()), net_map_at(inst->GetInput2()), net_map_at(inst->GetOutput()));
+		import_attributes(cell->attributes, inst);
 		return true;
 	}
 
 	if (inst->Type() == PRIM_NAND) {
-		RTLIL::SigSpec tmp = module->addWire(NEW_ID);
-		module->addAnd(NEW_ID, net_map_at(inst->GetInput1()), net_map_at(inst->GetInput2()), tmp);
-		module->addNot(inst_name, tmp, net_map_at(inst->GetOutput()));
+		RTLIL::SigSpec tmp = module->addWire(new_verific_id(inst));
+		cell = module->addAnd(new_verific_id(inst), net_map_at(inst->GetInput1()), net_map_at(inst->GetInput2()), tmp);
+		import_attributes(cell->attributes, inst);
+		cell = module->addNot(inst_name, tmp, net_map_at(inst->GetOutput()));
+		import_attributes(cell->attributes, inst);
 		return true;
 	}
 
 	if (inst->Type() == PRIM_OR) {
-		module->addOr(inst_name, net_map_at(inst->GetInput1()), net_map_at(inst->GetInput2()), net_map_at(inst->GetOutput()));
+		cell = module->addOr(inst_name, net_map_at(inst->GetInput1()), net_map_at(inst->GetInput2()), net_map_at(inst->GetOutput()));
+		import_attributes(cell->attributes, inst);
 		return true;
 	}
 
 	if (inst->Type() == PRIM_NOR) {
-		RTLIL::SigSpec tmp = module->addWire(NEW_ID);
-		module->addOr(NEW_ID, net_map_at(inst->GetInput1()), net_map_at(inst->GetInput2()), tmp);
-		module->addNot(inst_name, tmp, net_map_at(inst->GetOutput()));
+		RTLIL::SigSpec tmp = module->addWire(new_verific_id(inst));
+		cell = module->addOr(new_verific_id(inst), net_map_at(inst->GetInput1()), net_map_at(inst->GetInput2()), tmp);
+		import_attributes(cell->attributes, inst);
+		cell = module->addNot(inst_name, tmp, net_map_at(inst->GetOutput()));
+		import_attributes(cell->attributes, inst);
 		return true;
 	}
 
 	if (inst->Type() == PRIM_XOR) {
-		module->addXor(inst_name, net_map_at(inst->GetInput1()), net_map_at(inst->GetInput2()), net_map_at(inst->GetOutput()));
+		cell = module->addXor(inst_name, net_map_at(inst->GetInput1()), net_map_at(inst->GetInput2()), net_map_at(inst->GetOutput()));
+		import_attributes(cell->attributes, inst);
 		return true;
 	}
 
 	if (inst->Type() == PRIM_XNOR) {
-		module->addXnor(inst_name, net_map_at(inst->GetInput1()), net_map_at(inst->GetInput2()), net_map_at(inst->GetOutput()));
+		cell = module->addXnor(inst_name, net_map_at(inst->GetInput1()), net_map_at(inst->GetInput2()), net_map_at(inst->GetOutput()));
+		import_attributes(cell->attributes, inst);
 		return true;
 	}
 
 	if (inst->Type() == PRIM_INV) {
-		module->addNot(inst_name, net_map_at(inst->GetInput()), net_map_at(inst->GetOutput()));
+		cell = module->addNot(inst_name, net_map_at(inst->GetInput()), net_map_at(inst->GetOutput()));
+		import_attributes(cell->attributes, inst);
 		return true;
 	}
 
 	if (inst->Type() == PRIM_MUX) {
-		module->addMux(inst_name, net_map_at(inst->GetInput1()), net_map_at(inst->GetInput2()), net_map_at(inst->GetControl()), net_map_at(inst->GetOutput()));
+		cell = module->addMux(inst_name, net_map_at(inst->GetInput1()), net_map_at(inst->GetInput2()), net_map_at(inst->GetControl()), net_map_at(inst->GetOutput()));
+		import_attributes(cell->attributes, inst);
 		return true;
 	}
 
 	if (inst->Type() == PRIM_TRI) {
-		module->addMux(inst_name, RTLIL::State::Sz, net_map_at(inst->GetInput()), net_map_at(inst->GetControl()), net_map_at(inst->GetOutput()));
+		cell = module->addMux(inst_name, RTLIL::State::Sz, net_map_at(inst->GetInput()), net_map_at(inst->GetControl()), net_map_at(inst->GetOutput()));
+		import_attributes(cell->attributes, inst);
 		return true;
 	}
 
 	if (inst->Type() == PRIM_FADD)
 	{
-		RTLIL::SigSpec a_plus_b = module->addWire(NEW_ID, 2);
-		RTLIL::SigSpec y = inst->GetOutput() ? net_map_at(inst->GetOutput()) : module->addWire(NEW_ID);
+		RTLIL::SigSpec a_plus_b = module->addWire(new_verific_id(inst), 2);
+		RTLIL::SigSpec y = inst->GetOutput() ? net_map_at(inst->GetOutput()) : module->addWire(new_verific_id(inst));
 		if (inst->GetCout())
 			y.append(net_map_at(inst->GetCout()));
-		module->addAdd(NEW_ID, net_map_at(inst->GetInput1()), net_map_at(inst->GetInput2()), a_plus_b);
-		module->addAdd(inst_name, a_plus_b, net_map_at(inst->GetCin()), y);
+		cell = module->addAdd(new_verific_id(inst), net_map_at(inst->GetInput1()), net_map_at(inst->GetInput2()), a_plus_b);
+		import_attributes(cell->attributes, inst);
+		cell = module->addAdd(inst_name, a_plus_b, net_map_at(inst->GetCin()), y);
+		import_attributes(cell->attributes, inst);
 		return true;
 	}
 
@@ -372,24 +421,26 @@ bool VerificImporter::import_netlist_instance_cells(Instance *inst, RTLIL::IdStr
 		log_assert(clocking.body_net == nullptr);
 
 		if (inst->GetSet()->IsGnd() && inst->GetReset()->IsGnd())
-			clocking.addDff(inst_name, net_map_at(inst->GetInput()), net_map_at(inst->GetOutput()));
+			cell = clocking.addDff(inst_name, net_map_at(inst->GetInput()), net_map_at(inst->GetOutput()));
 		else if (inst->GetSet()->IsGnd())
-			clocking.addAdff(inst_name, net_map_at(inst->GetReset()), net_map_at(inst->GetInput()), net_map_at(inst->GetOutput()), RTLIL::State::S0);
+			cell = clocking.addAdff(inst_name, net_map_at(inst->GetReset()), net_map_at(inst->GetInput()), net_map_at(inst->GetOutput()), RTLIL::State::S0);
 		else if (inst->GetReset()->IsGnd())
-			clocking.addAdff(inst_name, net_map_at(inst->GetSet()), net_map_at(inst->GetInput()), net_map_at(inst->GetOutput()), RTLIL::State::S1);
+			cell = clocking.addAdff(inst_name, net_map_at(inst->GetSet()), net_map_at(inst->GetInput()), net_map_at(inst->GetOutput()), RTLIL::State::S1);
 		else
-			clocking.addDffsr(inst_name, net_map_at(inst->GetSet()), net_map_at(inst->GetReset()),
+			cell = clocking.addDffsr(inst_name, net_map_at(inst->GetSet()), net_map_at(inst->GetReset()),
 					net_map_at(inst->GetInput()), net_map_at(inst->GetOutput()));
+		import_attributes(cell->attributes, inst);
 		return true;
 	}
 
 	if (inst->Type() == PRIM_DLATCHRS)
 	{
 		if (inst->GetSet()->IsGnd() && inst->GetReset()->IsGnd())
-			module->addDlatch(inst_name, net_map_at(inst->GetControl()), net_map_at(inst->GetInput()), net_map_at(inst->GetOutput()));
+			cell = module->addDlatch(inst_name, net_map_at(inst->GetControl()), net_map_at(inst->GetInput()), net_map_at(inst->GetOutput()));
 		else
-			module->addDlatchsr(inst_name, net_map_at(inst->GetControl()), net_map_at(inst->GetSet()), net_map_at(inst->GetReset()),
+			cell = module->addDlatchsr(inst_name, net_map_at(inst->GetControl()), net_map_at(inst->GetSet()), net_map_at(inst->GetReset()),
 					net_map_at(inst->GetInput()), net_map_at(inst->GetOutput()));
+		import_attributes(cell->attributes, inst);
 		return true;
 	}
 
@@ -405,37 +456,45 @@ bool VerificImporter::import_netlist_instance_cells(Instance *inst, RTLIL::IdStr
 		if (inst->GetCout() != NULL)
 			out.append(net_map_at(inst->GetCout()));
 		if (inst->GetCin()->IsGnd()) {
-			module->addAdd(inst_name, IN1, IN2, out, SIGNED);
+			cell = module->addAdd(inst_name, IN1, IN2, out, SIGNED);
+			import_attributes(cell->attributes, inst);
 		} else {
-			RTLIL::SigSpec tmp = module->addWire(NEW_ID, GetSize(out));
-			module->addAdd(NEW_ID, IN1, IN2, tmp, SIGNED);
-			module->addAdd(inst_name, tmp, net_map_at(inst->GetCin()), out, false);
+			RTLIL::SigSpec tmp = module->addWire(new_verific_id(inst), GetSize(out));
+			cell = module->addAdd(new_verific_id(inst), IN1, IN2, tmp, SIGNED);
+			import_attributes(cell->attributes, inst);
+			cell = module->addAdd(inst_name, tmp, net_map_at(inst->GetCin()), out, false);
+			import_attributes(cell->attributes, inst);
 		}
 		return true;
 	}
 
 	if (inst->Type() == OPER_MULTIPLIER) {
-		module->addMul(inst_name, IN1, IN2, OUT, SIGNED);
+		cell = module->addMul(inst_name, IN1, IN2, OUT, SIGNED);
+		import_attributes(cell->attributes, inst);
 		return true;
 	}
 
 	if (inst->Type() == OPER_DIVIDER) {
-		module->addDiv(inst_name, IN1, IN2, OUT, SIGNED);
+		cell = module->addDiv(inst_name, IN1, IN2, OUT, SIGNED);
+		import_attributes(cell->attributes, inst);
 		return true;
 	}
 
 	if (inst->Type() == OPER_MODULO) {
-		module->addMod(inst_name, IN1, IN2, OUT, SIGNED);
+		cell = module->addMod(inst_name, IN1, IN2, OUT, SIGNED);
+		import_attributes(cell->attributes, inst);
 		return true;
 	}
 
 	if (inst->Type() == OPER_REMAINDER) {
-		module->addMod(inst_name, IN1, IN2, OUT, SIGNED);
+		cell = module->addMod(inst_name, IN1, IN2, OUT, SIGNED);
+		import_attributes(cell->attributes, inst);
 		return true;
 	}
 
 	if (inst->Type() == OPER_SHIFT_LEFT) {
-		module->addShl(inst_name, IN1, IN2, OUT, false);
+		cell = module->addShl(inst_name, IN1, IN2, OUT, false);
+		import_attributes(cell->attributes, inst);
 		return true;
 	}
 
@@ -445,7 +504,8 @@ bool VerificImporter::import_netlist_instance_cells(Instance *inst, RTLIL::IdStr
 		for (unsigned i = 1; i < inst->OutputSize(); i++) {
 			vec.append(RTLIL::State::S0);
 		}
-		module->addShl(inst_name, vec, IN, OUT, false);
+		cell = module->addShl(inst_name, vec, IN, OUT, false);
+		import_attributes(cell->attributes, inst);
 		return true;
 	}
 
@@ -455,7 +515,8 @@ bool VerificImporter::import_netlist_instance_cells(Instance *inst, RTLIL::IdStr
 		for (unsigned i = 1; i < inst->OutputSize(); i++) {
 			vec.append(RTLIL::State::S0);
 		}
-		module->addShl(inst_name, vec, IN, OUT, false);
+		cell = module->addShl(inst_name, vec, IN, OUT, false);
+		import_attributes(cell->attributes, inst);
 		return true;
 	}
 
@@ -463,108 +524,127 @@ bool VerificImporter::import_netlist_instance_cells(Instance *inst, RTLIL::IdStr
 		Net *net_cin = inst->GetCin();
 		Net *net_a_msb = inst->GetInput1Bit(0);
 		if (net_cin->IsGnd())
-			module->addShr(inst_name, IN1, IN2, OUT, false);
+			cell = module->addShr(inst_name, IN1, IN2, OUT, false);
 		else if (net_cin == net_a_msb)
-			module->addSshr(inst_name, IN1, IN2, OUT, true);
+			cell = module->addSshr(inst_name, IN1, IN2, OUT, true);
 		else
 			log_error("Can't import Verific OPER_SHIFT_RIGHT instance %s: carry_in is neither 0 nor msb of left input\n", inst->Name());
+		import_attributes(cell->attributes, inst);
 		return true;
 	}
 
 	if (inst->Type() == OPER_REDUCE_AND) {
-		module->addReduceAnd(inst_name, IN, net_map_at(inst->GetOutput()), SIGNED);
+		cell = module->addReduceAnd(inst_name, IN, net_map_at(inst->GetOutput()), SIGNED);
+		import_attributes(cell->attributes, inst);
 		return true;
 	}
 
 	if (inst->Type() == OPER_REDUCE_OR) {
-		module->addReduceOr(inst_name, IN, net_map_at(inst->GetOutput()), SIGNED);
+		cell = module->addReduceOr(inst_name, IN, net_map_at(inst->GetOutput()), SIGNED);
+		import_attributes(cell->attributes, inst);
 		return true;
 	}
 
 	if (inst->Type() == OPER_REDUCE_XOR) {
-		module->addReduceXor(inst_name, IN, net_map_at(inst->GetOutput()), SIGNED);
+		cell = module->addReduceXor(inst_name, IN, net_map_at(inst->GetOutput()), SIGNED);
+		import_attributes(cell->attributes, inst);
 		return true;
 	}
 
 	if (inst->Type() == OPER_REDUCE_XNOR) {
-		module->addReduceXnor(inst_name, IN, net_map_at(inst->GetOutput()), SIGNED);
+		cell = module->addReduceXnor(inst_name, IN, net_map_at(inst->GetOutput()), SIGNED);
+		import_attributes(cell->attributes, inst);
 		return true;
 	}
 
 	if (inst->Type() == OPER_REDUCE_NOR) {
-		SigSpec t = module->ReduceOr(NEW_ID, IN, SIGNED);
-		module->addNot(inst_name, t, net_map_at(inst->GetOutput()));
+		SigSpec t = module->ReduceOr(new_verific_id(inst), IN, SIGNED);
+		cell = module->addNot(inst_name, t, net_map_at(inst->GetOutput()));
+		import_attributes(cell->attributes, inst);
 		return true;
 	}
 
 	if (inst->Type() == OPER_LESSTHAN) {
 		Net *net_cin = inst->GetCin();
 		if (net_cin->IsGnd())
-			module->addLt(inst_name, IN1, IN2, net_map_at(inst->GetOutput()), SIGNED);
+			cell = module->addLt(inst_name, IN1, IN2, net_map_at(inst->GetOutput()), SIGNED);
 		else if (net_cin->IsPwr())
-			module->addLe(inst_name, IN1, IN2, net_map_at(inst->GetOutput()), SIGNED);
+			cell = module->addLe(inst_name, IN1, IN2, net_map_at(inst->GetOutput()), SIGNED);
 		else
 			log_error("Can't import Verific OPER_LESSTHAN instance %s: carry_in is neither 0 nor 1\n", inst->Name());
+		import_attributes(cell->attributes, inst);
 		return true;
 	}
 
 	if (inst->Type() == OPER_WIDE_AND) {
-		module->addAnd(inst_name, IN1, IN2, OUT, SIGNED);
+		cell = module->addAnd(inst_name, IN1, IN2, OUT, SIGNED);
+		import_attributes(cell->attributes, inst);
 		return true;
 	}
 
 	if (inst->Type() == OPER_WIDE_OR) {
-		module->addOr(inst_name, IN1, IN2, OUT, SIGNED);
+		cell = module->addOr(inst_name, IN1, IN2, OUT, SIGNED);
+		import_attributes(cell->attributes, inst);
 		return true;
 	}
 
 	if (inst->Type() == OPER_WIDE_XOR) {
-		module->addXor(inst_name, IN1, IN2, OUT, SIGNED);
+		cell = module->addXor(inst_name, IN1, IN2, OUT, SIGNED);
+		import_attributes(cell->attributes, inst);
 		return true;
 	}
 
 	if (inst->Type() == OPER_WIDE_XNOR) {
-		module->addXnor(inst_name, IN1, IN2, OUT, SIGNED);
+		cell = module->addXnor(inst_name, IN1, IN2, OUT, SIGNED);
+		import_attributes(cell->attributes, inst);
 		return true;
 	}
 
 	if (inst->Type() == OPER_WIDE_BUF) {
-		module->addPos(inst_name, IN, FILTERED_OUT, SIGNED);
+		cell = module->addPos(inst_name, IN, FILTERED_OUT, SIGNED);
+		import_attributes(cell->attributes, inst);
 		return true;
 	}
 
 	if (inst->Type() == OPER_WIDE_INV) {
-		module->addNot(inst_name, IN, OUT, SIGNED);
+		cell = module->addNot(inst_name, IN, OUT, SIGNED);
+		import_attributes(cell->attributes, inst);
 		return true;
 	}
 
 	if (inst->Type() == OPER_MINUS) {
-		module->addSub(inst_name, IN1, IN2, OUT, SIGNED);
+		cell = module->addSub(inst_name, IN1, IN2, OUT, SIGNED);
+		import_attributes(cell->attributes, inst);
 		return true;
 	}
 
 	if (inst->Type() == OPER_UMINUS) {
-		module->addNeg(inst_name, IN, OUT, SIGNED);
+		cell = module->addNeg(inst_name, IN, OUT, SIGNED);
+		import_attributes(cell->attributes, inst);
 		return true;
 	}
 
 	if (inst->Type() == OPER_EQUAL) {
-		module->addEq(inst_name, IN1, IN2, net_map_at(inst->GetOutput()), SIGNED);
+		cell = module->addEq(inst_name, IN1, IN2, net_map_at(inst->GetOutput()), SIGNED);
+		import_attributes(cell->attributes, inst);
 		return true;
 	}
 
 	if (inst->Type() == OPER_NEQUAL) {
-		module->addNe(inst_name, IN1, IN2, net_map_at(inst->GetOutput()), SIGNED);
+		cell = module->addNe(inst_name, IN1, IN2, net_map_at(inst->GetOutput()), SIGNED);
+		import_attributes(cell->attributes, inst);
 		return true;
 	}
 
 	if (inst->Type() == OPER_WIDE_MUX) {
-		module->addMux(inst_name, IN1, IN2, net_map_at(inst->GetControl()), OUT);
+		cell = module->addMux(inst_name, IN1, IN2, net_map_at(inst->GetControl()), OUT);
+		import_attributes(cell->attributes, inst);
 		return true;
 	}
 
 	if (inst->Type() == OPER_NTO1MUX) {
-		module->addShr(inst_name, IN2, IN1, net_map_at(inst->GetOutput()));
+		cell = module->addShr(inst_name, IN2, IN1, net_map_at(inst->GetOutput()));
+		import_attributes(cell->attributes, inst);
 		return true;
 	}
 
@@ -584,25 +664,29 @@ bool VerificImporter::import_netlist_instance_cells(Instance *inst, RTLIL::IdStr
 			padded_data.append(d);
 		}
 
-		module->addShr(inst_name, padded_data, sel, out);
+		cell = module->addShr(inst_name, padded_data, sel, out);
+		import_attributes(cell->attributes, inst);
 		return true;
 	}
 
 	if (inst->Type() == OPER_SELECTOR)
 	{
-		module->addPmux(inst_name, State::S0, IN2, IN1, net_map_at(inst->GetOutput()));
+		cell = module->addPmux(inst_name, State::S0, IN2, IN1, net_map_at(inst->GetOutput()));
+		import_attributes(cell->attributes, inst);
 		return true;
 	}
 
 	if (inst->Type() == OPER_WIDE_SELECTOR)
 	{
 		SigSpec out = OUT;
-		module->addPmux(inst_name, SigSpec(State::S0, GetSize(out)), IN2, IN1, out);
+		cell = module->addPmux(inst_name, SigSpec(State::S0, GetSize(out)), IN2, IN1, out);
+		import_attributes(cell->attributes, inst);
 		return true;
 	}
 
 	if (inst->Type() == OPER_WIDE_TRI) {
-		module->addMux(inst_name, RTLIL::SigSpec(RTLIL::State::Sz, inst->OutputSize()), IN, net_map_at(inst->GetControl()), OUT);
+		cell = module->addMux(inst_name, RTLIL::SigSpec(RTLIL::State::Sz, inst->OutputSize()), IN, net_map_at(inst->GetControl()), OUT);
+		import_attributes(cell->attributes, inst);
 		return true;
 	}
 
@@ -616,9 +700,10 @@ bool VerificImporter::import_netlist_instance_cells(Instance *inst, RTLIL::IdStr
 		RTLIL::SigSpec sig_reset = operatorInport(inst, "reset");
 
 		if (sig_set.is_fully_const() && !sig_set.as_bool() && sig_reset.is_fully_const() && !sig_reset.as_bool())
-			clocking.addDff(inst_name, IN, OUT);
+			cell = clocking.addDff(inst_name, IN, OUT);
 		else
-			clocking.addDffsr(inst_name, sig_set, sig_reset, IN, OUT);
+			cell = clocking.addDffsr(inst_name, sig_set, sig_reset, IN, OUT);
+		import_attributes(cell->attributes, inst);
 
 		return true;
 	}
@@ -701,13 +786,14 @@ void VerificImporter::merge_past_ffs(pool<RTLIL::Cell*> &candidates)
 
 void VerificImporter::import_netlist(RTLIL::Design *design, Netlist *nl, std::set<Netlist*> &nl_todo)
 {
-	std::string module_name = nl->IsOperator() ? std::string("$verific$") + nl->Owner()->Name() : RTLIL::escape_id(nl->Owner()->Name());
+	std::string netlist_name = nl->GetAtt(" \\top") ? nl->CellBaseName() : nl->Owner()->Name();
+	std::string module_name = nl->IsOperator() ? "$verific$" + netlist_name : RTLIL::escape_id(netlist_name);
 
 	netlist = nl;
 
 	if (design->has(module_name)) {
-		if (!nl->IsOperator())
-			log_cmd_error("Re-definition of module `%s'.\n", nl->Owner()->Name());
+		if (!nl->IsOperator() && !is_blackbox(nl))
+			log_cmd_error("Re-definition of module `%s'.\n", netlist_name.c_str());
 		return;
 	}
 
@@ -715,7 +801,7 @@ void VerificImporter::import_netlist(RTLIL::Design *design, Netlist *nl, std::se
 	module->name = module_name;
 	design->add(module);
 
-	if (nl->IsBlackBox()) {
+	if (is_blackbox(nl)) {
 		log("Importing blackbox module %s.\n", RTLIL::id2cstr(module->name));
 		module->set_bool_attribute("\\blackbox");
 	} else {
@@ -847,7 +933,7 @@ void VerificImporter::import_netlist(RTLIL::Design *design, Netlist *nl, std::se
 						ascii_initdata++;
 					}
 					if (initval_valid) {
-						RTLIL::Cell *cell = module->addCell(NEW_ID, "$meminit");
+						RTLIL::Cell *cell = module->addCell(new_verific_id(net), "$meminit");
 						cell->parameters["\\WORDS"] = 1;
 						if (net->GetOrigTypeRange()->LeftRangeBound() < net->GetOrigTypeRange()->RightRangeBound())
 							cell->setPort("\\ADDR", word_idx);
@@ -910,7 +996,7 @@ void VerificImporter::import_netlist(RTLIL::Design *design, Netlist *nl, std::se
 		if (net->Bus())
 			continue;
 
-		RTLIL::IdString wire_name = module->uniquify(mode_names || net->IsUserDeclared() ? RTLIL::escape_id(net->Name()) : NEW_ID);
+		RTLIL::IdString wire_name = module->uniquify(mode_names || net->IsUserDeclared() ? RTLIL::escape_id(net->Name()) : new_verific_id(net));
 
 		if (verific_verbose)
 			log("  importing net %s as %s.\n", net->Name(), log_id(wire_name));
@@ -934,7 +1020,7 @@ void VerificImporter::import_netlist(RTLIL::Design *design, Netlist *nl, std::se
 
 		if (found_new_net)
 		{
-			RTLIL::IdString wire_name = module->uniquify(mode_names || netbus->IsUserDeclared() ? RTLIL::escape_id(netbus->Name()) : NEW_ID);
+			RTLIL::IdString wire_name = module->uniquify(mode_names || netbus->IsUserDeclared() ? RTLIL::escape_id(netbus->Name()) : new_verific_id(netbus));
 
 			if (verific_verbose)
 				log("  importing netbus %s as %s.\n", netbus->Name(), log_id(wire_name));
@@ -1010,16 +1096,16 @@ void VerificImporter::import_netlist(RTLIL::Design *design, Netlist *nl, std::se
 		}
 
 		if (GetSize(anyconst_sig))
-			module->connect(anyconst_sig, module->Anyconst(NEW_ID, GetSize(anyconst_sig)));
+			module->connect(anyconst_sig, module->Anyconst(new_verific_id(netbus), GetSize(anyconst_sig)));
 
 		if (GetSize(anyseq_sig))
-			module->connect(anyseq_sig, module->Anyseq(NEW_ID, GetSize(anyseq_sig)));
+			module->connect(anyseq_sig, module->Anyseq(new_verific_id(netbus), GetSize(anyseq_sig)));
 
 		if (GetSize(allconst_sig))
-			module->connect(allconst_sig, module->Allconst(NEW_ID, GetSize(allconst_sig)));
+			module->connect(allconst_sig, module->Allconst(new_verific_id(netbus), GetSize(allconst_sig)));
 
 		if (GetSize(allseq_sig))
-			module->connect(allseq_sig, module->Allseq(NEW_ID, GetSize(allseq_sig)));
+			module->connect(allseq_sig, module->Allseq(new_verific_id(netbus), GetSize(allseq_sig)));
 	}
 
 	for (auto it : init_nets)
@@ -1043,10 +1129,10 @@ void VerificImporter::import_netlist(RTLIL::Design *design, Netlist *nl, std::se
 	}
 
 	for (auto net : anyconst_nets)
-		module->connect(net_map_at(net), module->Anyconst(NEW_ID));
+		module->connect(net_map_at(net), module->Anyconst(new_verific_id(net)));
 
 	for (auto net : anyseq_nets)
-		module->connect(net_map_at(net), module->Anyseq(NEW_ID));
+		module->connect(net_map_at(net), module->Anyseq(new_verific_id(net)));
 
 	pool<Instance*, hash_ptr_ops> sva_asserts;
 	pool<Instance*, hash_ptr_ops> sva_assumes;
@@ -1057,7 +1143,7 @@ void VerificImporter::import_netlist(RTLIL::Design *design, Netlist *nl, std::se
 
 	FOREACH_INSTANCE_OF_NETLIST(nl, mi, inst)
 	{
-		RTLIL::IdString inst_name = module->uniquify(mode_names || inst->IsUserDeclared() ? RTLIL::escape_id(inst->Name()) : NEW_ID);
+		RTLIL::IdString inst_name = module->uniquify(mode_names || inst->IsUserDeclared() ? RTLIL::escape_id(inst->Name()) : new_verific_id(inst));
 
 		if (verific_verbose)
 			log("  importing cell %s (%s) as %s.\n", inst->Name(), inst->View()->Owner()->Name(), log_id(inst_name));
@@ -1125,27 +1211,34 @@ void VerificImporter::import_netlist(RTLIL::Design *design, Netlist *nl, std::se
 		if (inst->Type() == OPER_WRITE_PORT || inst->Type() == OPER_CLOCKED_WRITE_PORT)
 		{
 			RTLIL::Memory *memory = module->memories.at(RTLIL::escape_id(inst->GetOutput()->Name()));
-			if (memory->width != int(inst->Input2Size()))
-				log_error("Import of asymmetric memories of this type is not supported yet: %s %s\n", inst->Name(), inst->GetInput()->Name());
+			int numchunks = int(inst->Input2Size()) / memory->width;
+			int chunksbits = ceil_log2(numchunks);
+
+			if ((numchunks * memory->width) != int(inst->Input2Size()) || (numchunks & (numchunks - 1)) != 0)
+				log_error("Import of asymmetric memories of this type is not supported yet: %s %s\n", inst->Name(), inst->GetOutput()->Name());
 
-			RTLIL::SigSpec addr = operatorInput1(inst);
-			RTLIL::SigSpec data = operatorInput2(inst);
-
-			RTLIL::Cell *cell = module->addCell(inst_name, "$memwr");
-			cell->parameters["\\MEMID"] = memory->name.str();
-			cell->parameters["\\CLK_ENABLE"] = false;
-			cell->parameters["\\CLK_POLARITY"] = true;
-			cell->parameters["\\PRIORITY"] = 0;
-			cell->parameters["\\ABITS"] = GetSize(addr);
-			cell->parameters["\\WIDTH"] = GetSize(data);
-			cell->setPort("\\EN", RTLIL::SigSpec(net_map_at(inst->GetControl())).repeat(GetSize(data)));
-			cell->setPort("\\CLK", RTLIL::State::S0);
-			cell->setPort("\\ADDR", addr);
-			cell->setPort("\\DATA", data);
-
-			if (inst->Type() == OPER_CLOCKED_WRITE_PORT) {
-				cell->parameters["\\CLK_ENABLE"] = true;
-				cell->setPort("\\CLK", net_map_at(inst->GetClock()));
+			for (int i = 0; i < numchunks; i++)
+			{
+				RTLIL::SigSpec addr = {operatorInput1(inst), RTLIL::Const(i, chunksbits)};
+				RTLIL::SigSpec data = operatorInput2(inst).extract(i * memory->width, memory->width);
+
+				RTLIL::Cell *cell = module->addCell(numchunks == 1 ? inst_name :
+						RTLIL::IdString(stringf("%s_%d", inst_name.c_str(), i)), "$memwr");
+				cell->parameters["\\MEMID"] = memory->name.str();
+				cell->parameters["\\CLK_ENABLE"] = false;
+				cell->parameters["\\CLK_POLARITY"] = true;
+				cell->parameters["\\PRIORITY"] = 0;
+				cell->parameters["\\ABITS"] = GetSize(addr);
+				cell->parameters["\\WIDTH"] = GetSize(data);
+				cell->setPort("\\EN", RTLIL::SigSpec(net_map_at(inst->GetControl())).repeat(GetSize(data)));
+				cell->setPort("\\CLK", RTLIL::State::S0);
+				cell->setPort("\\ADDR", addr);
+				cell->setPort("\\DATA", data);
+
+				if (inst->Type() == OPER_CLOCKED_WRITE_PORT) {
+					cell->parameters["\\CLK_ENABLE"] = true;
+					cell->setPort("\\CLK", net_map_at(inst->GetClock()));
+				}
 			}
 			continue;
 		}
@@ -1181,7 +1274,7 @@ void VerificImporter::import_netlist(RTLIL::Design *design, Netlist *nl, std::se
 			log_assert(inst->Input1Size() == inst->OutputSize());
 
 			SigSpec sig_d, sig_q, sig_o;
-			sig_q = module->addWire(NEW_ID, inst->Input1Size());
+			sig_q = module->addWire(new_verific_id(inst), inst->Input1Size());
 
 			for (int i = int(inst->Input1Size())-1; i >= 0; i--){
 				sig_d.append(net_map_at(inst->GetInput1Bit(i)));
@@ -1195,8 +1288,8 @@ void VerificImporter::import_netlist(RTLIL::Design *design, Netlist *nl, std::se
 						log_signal(sig_d), log_signal(sig_q), log_signal(sig_o));
 			}
 
-			clocking.addDff(NEW_ID, sig_d, sig_q);
-			module->addXnor(NEW_ID, sig_d, sig_q, sig_o);
+			clocking.addDff(new_verific_id(inst), sig_d, sig_q);
+			module->addXnor(new_verific_id(inst), sig_d, sig_q, sig_o);
 
 			if (!mode_keep)
 				continue;
@@ -1210,7 +1303,7 @@ void VerificImporter::import_netlist(RTLIL::Design *design, Netlist *nl, std::se
 
 			SigSpec sig_d = net_map_at(inst->GetInput1());
 			SigSpec sig_o = net_map_at(inst->GetOutput());
-			SigSpec sig_q = module->addWire(NEW_ID);
+			SigSpec sig_q = module->addWire(new_verific_id(inst));
 
 			if (verific_verbose) {
 				log("    %sedge FF with D=%s, Q=%s, C=%s.\n", clocking.posedge ? "pos" : "neg",
@@ -1219,8 +1312,8 @@ void VerificImporter::import_netlist(RTLIL::Design *design, Netlist *nl, std::se
 						log_signal(sig_d), log_signal(sig_q), log_signal(sig_o));
 			}
 
-			clocking.addDff(NEW_ID, sig_d, sig_q);
-			module->addXnor(NEW_ID, sig_d, sig_q, sig_o);
+			clocking.addDff(new_verific_id(inst), sig_d, sig_q);
+			module->addXnor(new_verific_id(inst), sig_d, sig_q, sig_o);
 
 			if (!mode_keep)
 				continue;
@@ -1239,7 +1332,7 @@ void VerificImporter::import_netlist(RTLIL::Design *design, Netlist *nl, std::se
 				log("    %sedge FF with D=%s, Q=%s, C=%s.\n", clocking.posedge ? "pos" : "neg",
 						log_signal(sig_d), log_signal(sig_q), log_signal(clocking.clock_sig));
 
-			past_ffs.insert(clocking.addDff(NEW_ID, sig_d, sig_q));
+			past_ffs.insert(clocking.addDff(new_verific_id(inst), sig_d, sig_q));
 
 			if (!mode_keep)
 				continue;
@@ -1253,14 +1346,14 @@ void VerificImporter::import_netlist(RTLIL::Design *design, Netlist *nl, std::se
 
 			SigBit sig_d = net_map_at(inst->GetInput1());
 			SigBit sig_o = net_map_at(inst->GetOutput());
-			SigBit sig_q = module->addWire(NEW_ID);
+			SigBit sig_q = module->addWire(new_verific_id(inst));
 
 			if (verific_verbose)
 				log("    %sedge FF with D=%s, Q=%s, C=%s.\n", clocking.posedge ? "pos" : "neg",
 						log_signal(sig_d), log_signal(sig_q), log_signal(clocking.clock_sig));
 
-			clocking.addDff(NEW_ID, sig_d, sig_q);
-			module->addEq(NEW_ID, {sig_q, sig_d}, Const(inst->Type() == PRIM_SVA_ROSE ? 1 : 2, 2), sig_o);
+			clocking.addDff(new_verific_id(inst), sig_d, sig_q);
+			module->addEq(new_verific_id(inst), {sig_q, sig_d}, Const(inst->Type() == PRIM_SVA_ROSE ? 1 : 2, 2), sig_o);
 
 			if (!mode_keep)
 				continue;
@@ -1283,9 +1376,9 @@ void VerificImporter::import_netlist(RTLIL::Design *design, Netlist *nl, std::se
 
 			Cell *cell = nullptr;
 			if (assume_attr != nullptr && !strcmp(assume_attr, "1"))
-				cell = module->addAssume(NEW_ID, cond, State::S1);
+				cell = module->addAssume(new_verific_id(inst), cond, State::S1);
 			else
-				cell = module->addAssert(NEW_ID, cond, State::S1);
+				cell = module->addAssert(new_verific_id(inst), cond, State::S1);
 
 			import_attributes(cell->attributes, inst);
 			continue;
@@ -1327,7 +1420,7 @@ void VerificImporter::import_netlist(RTLIL::Design *design, Netlist *nl, std::se
 			IdString port_name_id = RTLIL::escape_id(port_name);
 			auto &sigvec = cell_port_conns[port_name_id];
 			if (GetSize(sigvec) <= port_offset) {
-				SigSpec zwires = module->addWire(NEW_ID, port_offset+1-GetSize(sigvec));
+				SigSpec zwires = module->addWire(new_verific_id(inst), port_offset+1-GetSize(sigvec));
 				for (auto bit : zwires)
 					sigvec.push_back(bit);
 			}
@@ -1363,6 +1456,50 @@ void VerificImporter::import_netlist(RTLIL::Design *design, Netlist *nl, std::se
 
 		merge_past_ffs(past_ffs);
 	}
+
+	if (!mode_fullinit)
+	{
+		pool<SigBit> non_ff_bits;
+		CellTypes ff_types;
+
+		ff_types.setup_internals_ff();
+		ff_types.setup_stdcells_mem();
+
+		for (auto cell : module->cells())
+		{
+			if (ff_types.cell_known(cell->type))
+				continue;
+
+			for (auto conn : cell->connections())
+			{
+				if (!cell->output(conn.first))
+					continue;
+
+				for (auto bit : conn.second)
+					if (bit.wire != nullptr)
+						non_ff_bits.insert(bit);
+			}
+		}
+
+		for (auto wire : module->wires())
+		{
+			if (!wire->attributes.count("\\init"))
+				continue;
+
+			Const &initval = wire->attributes.at("\\init");
+			for (int i = 0; i < GetSize(initval); i++)
+			{
+				if (initval[i] != State::S0 && initval[i] != State::S1)
+					continue;
+
+				if (non_ff_bits.count(SigBit(wire, i)))
+					initval[i] = State::Sx;
+			}
+
+			if (initval.is_fully_undef())
+				wire->attributes.erase("\\init");
+		}
+	}
 }
 
 // ==================================================================
@@ -1537,30 +1674,35 @@ struct VerificExtNets
 	int portname_cnt = 0;
 
 	// a map from Net to the same Net one level up in the design hierarchy
-	std::map<Net*, Net*> net_level_up;
+	std::map<Net*, Net*> net_level_up_drive_up;
+	std::map<Net*, Net*> net_level_up_drive_down;
 
-	Net *get_net_level_up(Net *net)
+	Net *route_up(Net *net, bool drive_up, Net *final_net = nullptr)
 	{
+		auto &net_level_up = drive_up ? net_level_up_drive_up : net_level_up_drive_down;
+
 		if (net_level_up.count(net) == 0)
 		{
 			Netlist *nl = net->Owner();
 
 			// Simply return if Netlist is not unique
-			if (nl->NumOfRefs() != 1)
-				return net;
+			log_assert(nl->NumOfRefs() == 1);
 
 			Instance *up_inst = (Instance*)nl->GetReferences()->GetLast();
 			Netlist *up_nl = up_inst->Owner();
 
 			// create new Port
 			string name = stringf("___extnets_%d", portname_cnt++);
-			Port *new_port = new Port(name.c_str(), DIR_OUT);
+			Port *new_port = new Port(name.c_str(), drive_up ? DIR_OUT : DIR_IN);
 			nl->Add(new_port);
 			net->Connect(new_port);
 
 			// create new Net in up Netlist
-			Net *new_net = new Net(name.c_str());
-			up_nl->Add(new_net);
+			Net *new_net = final_net;
+			if (new_net == nullptr || new_net->Owner() != up_nl) {
+				new_net = new Net(name.c_str());
+				up_nl->Add(new_net);
+			}
 			up_inst->Connect(new_port, new_net);
 
 			net_level_up[net] = new_net;
@@ -1569,6 +1711,39 @@ struct VerificExtNets
 		return net_level_up.at(net);
 	}
 
+	Net *route_up(Net *net, bool drive_up, Netlist *dest, Net *final_net = nullptr)
+	{
+		while (net->Owner() != dest)
+			net = route_up(net, drive_up, final_net);
+		if (final_net != nullptr)
+			log_assert(net == final_net);
+		return net;
+	}
+
+	Netlist *find_common_ancestor(Netlist *A, Netlist *B)
+	{
+		std::set<Netlist*> ancestors_of_A;
+
+		Netlist *cursor = A;
+		while (1) {
+			ancestors_of_A.insert(cursor);
+			if (cursor->NumOfRefs() != 1)
+				break;
+			cursor = ((Instance*)cursor->GetReferences()->GetLast())->Owner();
+		}
+
+		cursor = B;
+		while (1) {
+			if (ancestors_of_A.count(cursor))
+				return cursor;
+			if (cursor->NumOfRefs() != 1)
+				break;
+			cursor = ((Instance*)cursor->GetReferences()->GetLast())->Owner();
+		}
+
+		log_error("No common ancestor found between %s and %s.\n", get_full_netlist_name(A).c_str(), get_full_netlist_name(B).c_str());
+	}
+
 	void run(Netlist *nl)
 	{
 		MapIter mi, mi2;
@@ -1592,19 +1767,37 @@ struct VerificExtNets
 			if (verific_verbose)
 				log("Fixing external net reference on port %s.%s.%s:\n", get_full_netlist_name(nl).c_str(), inst->Name(), port->Name());
 
-			while (net->IsExternalTo(nl))
-			{
-				Net *newnet = get_net_level_up(net);
-				if (newnet == net) break;
+			Netlist *ext_nl = net->Owner();
 
+			if (verific_verbose)
+				log(" external net owner: %s\n", get_full_netlist_name(ext_nl).c_str());
+
+			Netlist *ca_nl = find_common_ancestor(nl, ext_nl);
+
+			if (verific_verbose)
+				log(" common ancestor: %s\n", get_full_netlist_name(ca_nl).c_str());
+
+			Net *ca_net = route_up(net, !port->IsOutput(), ca_nl);
+			Net *new_net = ca_net;
+
+			if (ca_nl != nl)
+			{
 				if (verific_verbose)
-					log("  external net: %s.%s\n", get_full_netlist_name(net->Owner()).c_str(), net->Name());
-				net = newnet;
+					log(" net in common ancestor: %s\n", ca_net->Name());
+
+				string name = stringf("___extnets_%d", portname_cnt++);
+				new_net = new Net(name.c_str());
+				nl->Add(new_net);
+
+				Net *n YS_ATTRIBUTE(unused) = route_up(new_net, port->IsOutput(), ca_nl, ca_net);
+				log_assert(n == ca_net);
 			}
 
 			if (verific_verbose)
-				log("  final net: %s.%s%s\n", get_full_netlist_name(net->Owner()).c_str(), net->Name(), net->IsExternalTo(nl) ? " (external)" : "");
-			todo_connect.push_back(tuple<Instance*, Port*, Net*>(inst, port, net));
+				log(" new local net: %s\n", new_net->Name());
+
+			log_assert(!new_net->IsExternalTo(nl));
+			todo_connect.push_back(tuple<Instance*, Port*, Net*>(inst, port, new_net));
 		}
 
 		for (auto it : todo_connect) {
@@ -1614,30 +1807,64 @@ struct VerificExtNets
 	}
 };
 
-void verific_import(Design *design, std::string top)
+void verific_import(Design *design, const std::map<std::string,std::string> &parameters, std::string top)
 {
+	verific_sva_fsm_limit = 16;
+
 	std::set<Netlist*> nl_todo, nl_done;
 
-	{
-		VhdlLibrary *vhdl_lib = vhdl_file::GetLibrary("work", 1);
-		VeriLibrary *veri_lib = veri_file::GetLibrary("work", 1);
+	VhdlLibrary *vhdl_lib = vhdl_file::GetLibrary("work", 1);
+	VeriLibrary *veri_lib = veri_file::GetLibrary("work", 1);
+	Array *netlists = NULL;
+	Array veri_libs, vhdl_libs;
+	if (vhdl_lib) vhdl_libs.InsertLast(vhdl_lib);
+	if (veri_lib) veri_libs.InsertLast(veri_lib);
+
+	Map verific_params(STRING_HASH);
+	for (const auto &i : parameters)
+		verific_params.Insert(i.first.c_str(), i.second.c_str());
 
-		Array veri_libs, vhdl_libs;
-		if (vhdl_lib) vhdl_libs.InsertLast(vhdl_lib);
-		if (veri_lib) veri_libs.InsertLast(veri_lib);
+	if (top.empty()) {
+		netlists = hier_tree::ElaborateAll(&veri_libs, &vhdl_libs, &verific_params);
+	}
+	else {
+		Array veri_modules, vhdl_units;
+
+		if (veri_lib) {
+			VeriModule *veri_module = veri_lib->GetModule(top.c_str(), 1);
+			if (veri_module) {
+				veri_modules.InsertLast(veri_module);
+			}
 
-		Array *netlists = hier_tree::ElaborateAll(&veri_libs, &vhdl_libs);
-		Netlist *nl;
-		int i;
+			// Also elaborate all root modules since they may contain bind statements
+			MapIter mi;
+			FOREACH_VERILOG_MODULE_IN_LIBRARY(veri_lib, mi, veri_module) {
+				if (!veri_module->IsRootModule()) continue;
+				veri_modules.InsertLast(veri_module);
+			}
+		}
 
-		FOREACH_ARRAY_ITEM(netlists, i, nl) {
-			if (top.empty() || nl->Owner()->Name() == top)
-				nl_todo.insert(nl);
+		if (vhdl_lib) {
+			VhdlDesignUnit *vhdl_unit = vhdl_lib->GetPrimUnit(top.c_str());
+			if (vhdl_unit)
+				vhdl_units.InsertLast(vhdl_unit);
 		}
 
-		delete netlists;
+		netlists = hier_tree::Elaborate(&veri_modules, &vhdl_units, &verific_params);
+	}
+
+	Netlist *nl;
+	int i;
+
+	FOREACH_ARRAY_ITEM(netlists, i, nl) {
+		if (top.empty() && nl->CellBaseName() != top)
+			continue;
+		nl->AddAtt(new Att(" \\top", NULL));
+		nl_todo.insert(nl);
 	}
 
+	delete netlists;
+
 	if (!verific_error_msg.empty())
 		log_error("%s\n", verific_error_msg.c_str());
 
@@ -1648,7 +1875,7 @@ void verific_import(Design *design, std::string top)
 	while (!nl_todo.empty()) {
 		Netlist *nl = *nl_todo.begin();
 		if (nl_done.count(nl) == 0) {
-			VerificImporter importer(false, false, false, false, false, false);
+			VerificImporter importer(false, false, false, false, false, false, false);
 			importer.import_netlist(design, nl, nl_todo);
 		}
 		nl_todo.erase(nl);
@@ -1658,6 +1885,8 @@ void verific_import(Design *design, std::string top)
 	veri_file::Reset();
 	vhdl_file::Reset();
 	Libset::Reset();
+	verific_incdirs.clear();
+	verific_libdirs.clear();
 	verific_import_pending = false;
 
 	if (!verific_error_msg.empty())
@@ -1669,6 +1898,7 @@ YOSYS_NAMESPACE_END
 
 PRIVATE_NAMESPACE_BEGIN
 
+#ifdef YOSYS_ENABLE_VERIFIC
 bool check_noverific_env()
 {
 	const char *e = getenv("YOSYS_NOVERIFIC");
@@ -1678,10 +1908,11 @@ bool check_noverific_env()
 		return false;
 	return true;
 }
+#endif
 
 struct VerificPass : public Pass {
 	VerificPass() : Pass("verific", "load Verilog and VHDL designs using Verific") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -1702,11 +1933,18 @@ struct VerificPass : public Pass {
 		log("\n");
 		log("Like -sv, but define FORMAL instead of SYNTHESIS.\n");
 		log("\n");
+		log("\n");
 		log("    verific {-vhdl87|-vhdl93|-vhdl2k|-vhdl2008|-vhdl} <vhdl-file>..\n");
 		log("\n");
 		log("Load the specified VHDL files into Verific.\n");
 		log("\n");
 		log("\n");
+		log("    verific -work <libname> {-sv|-vhdl|...} <hdl-file>\n");
+		log("\n");
+		log("Load the specified Verilog/SystemVerilog/VHDL file into the specified library.\n");
+		log("(default library when -work is not present: \"work\")\n");
+		log("\n");
+		log("\n");
 		log("    verific -vlog-incdir <directory>..\n");
 		log("\n");
 		log("Add Verilog include directories.\n");
@@ -1728,6 +1966,15 @@ struct VerificPass : public Pass {
 		log("Remove Verilog defines previously set with -vlog-define.\n");
 		log("\n");
 		log("\n");
+		log("    verific -set-error <msg_id>..\n");
+		log("    verific -set-warning <msg_id>..\n");
+		log("    verific -set-info <msg_id>..\n");
+		log("    verific -set-ignore <msg_id>..\n");
+		log("\n");
+		log("Set message severity. <msg_id> is the string in square brackets when a message\n");
+		log("is printed, such as VERI-1209.\n");
+		log("\n");
+		log("\n");
 		log("    verific -import [options] <top-module>..\n");
 		log("\n");
 		log("Elaborate the design for the specified top modules, import to Yosys and\n");
@@ -1751,6 +1998,16 @@ struct VerificPass : public Pass {
 		log("  -autocover\n");
 		log("    Generate automatic cover statements for all asserts\n");
 		log("\n");
+		log("  -fullinit\n");
+		log("    Keep all register initializations, even those for non-FF registers.\n");
+		log("\n");
+		log("  -chparam name value \n");
+		log("    Elaborate the specified top modules (all modules when -all given) using\n");
+		log("    this parameter value. Modules on which this parameter does not exist will\n");
+		log("    cause Verific to produce a VERI-1928 or VHDL-1676 message. This option\n");
+		log("    can be specified multiple times to override multiple parameters.\n");
+		log("    String values must be passed in double quotes (\").\n");
+		log("\n");
 		log("  -v, -vv\n");
 		log("    Verbose log messages. (-vv is even more verbose than -v.)\n");
 		log("\n");
@@ -1769,6 +2026,9 @@ struct VerificPass : public Pass {
 		log("  -nosva\n");
 		log("    Ignore SVA properties, do not infer checker logic.\n");
 		log("\n");
+		log("  -L <int>\n");
+		log("    Maximum number of ctrl bits for SVA checker FSMs (default=16).\n");
+		log("\n");
 		log("  -n\n");
 		log("    Keep all Verific names on instances and nets. By default only\n");
 		log("    user-declared names are preserved.\n");
@@ -1780,23 +2040,51 @@ struct VerificPass : public Pass {
 		log("\n");
 	}
 #ifdef YOSYS_ENABLE_VERIFIC
-	virtual void execute(std::vector<std::string> args, RTLIL::Design *design)
+	void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
 	{
+		static bool set_verific_global_flags = true;
+
 		if (check_noverific_env())
 			log_cmd_error("This version of Yosys is built without Verific support.\n");
 
 		log_header(design, "Executing VERIFIC (loading SystemVerilog and VHDL designs using Verific).\n");
 
-		Message::SetConsoleOutput(0);
-		Message::RegisterCallBackMsg(msg_func);
-		RuntimeFlags::SetVar("db_preserve_user_nets", 1);
-		RuntimeFlags::SetVar("db_allow_external_nets", 1);
-		RuntimeFlags::SetVar("vhdl_ignore_assertion_statements", 0);
-		RuntimeFlags::SetVar("veri_extract_dualport_rams", 0);
-		RuntimeFlags::SetVar("veri_extract_multiport_rams", 1);
-		RuntimeFlags::SetVar("db_infer_wide_operators", 1);
+		if (set_verific_global_flags)
+		{
+			Message::SetConsoleOutput(0);
+			Message::RegisterCallBackMsg(msg_func);
+
+			RuntimeFlags::SetVar("db_preserve_user_nets", 1);
+			RuntimeFlags::SetVar("db_allow_external_nets", 1);
+			RuntimeFlags::SetVar("db_infer_wide_operators", 1);
+
+			RuntimeFlags::SetVar("veri_extract_dualport_rams", 0);
+			RuntimeFlags::SetVar("veri_extract_multiport_rams", 1);
+
+			RuntimeFlags::SetVar("vhdl_extract_dualport_rams", 0);
+			RuntimeFlags::SetVar("vhdl_extract_multiport_rams", 1);
+
+			RuntimeFlags::SetVar("vhdl_support_variable_slice", 1);
+			RuntimeFlags::SetVar("vhdl_ignore_assertion_statements", 0);
+
+			// Workaround for VIPER #13851
+			RuntimeFlags::SetVar("veri_create_name_for_unnamed_gen_block", 1);
+
+			// WARNING: instantiating unknown module 'XYZ' (VERI-1063)
+			Message::SetMessageType("VERI-1063", VERIFIC_ERROR);
+
+			// https://github.com/YosysHQ/yosys/issues/1055
+			RuntimeFlags::SetVar("veri_elaborate_top_level_modules_having_interface_ports", 1) ;
+
+#ifndef DB_PRESERVE_INITIAL_VALUE
+#  warning Verific was built without DB_PRESERVE_INITIAL_VALUE.
+#endif
+
+			set_verific_global_flags = false;
+		}
 
 		verific_verbose = 0;
+		verific_sva_fsm_limit = 16;
 
 		const char *release_str = Message::ReleaseString();
 		time_t release_time = Message::ReleaseDate();
@@ -1811,16 +2099,39 @@ struct VerificPass : public Pass {
 		log("Built with Verific %s, released at %s.\n", release_str, release_tmstr);
 
 		int argidx = 1;
+		std::string work = "work";
+
+		if (GetSize(args) > argidx && (args[argidx] == "-set-error" || args[argidx] == "-set-warning" ||
+				args[argidx] == "-set-info" || args[argidx] == "-set-ignore"))
+		{
+			msg_type_t new_type;
+
+			if (args[argidx] == "-set-error")
+				new_type = VERIFIC_ERROR;
+			else if (args[argidx] == "-set-warning")
+				new_type = VERIFIC_WARNING;
+			else if (args[argidx] == "-set-info")
+				new_type = VERIFIC_INFO;
+			else if (args[argidx] == "-set-ignore")
+				new_type = VERIFIC_IGNORE;
+			else
+				log_abort();
+
+			for (argidx++; argidx < GetSize(args); argidx++)
+				Message::SetMessageType(args[argidx].c_str(), new_type);
+
+			goto check_error;
+		}
 
 		if (GetSize(args) > argidx && args[argidx] == "-vlog-incdir") {
 			for (argidx++; argidx < GetSize(args); argidx++)
-				veri_file::AddIncludeDir(args[argidx].c_str());
+				verific_incdirs.push_back(args[argidx]);
 			goto check_error;
 		}
 
 		if (GetSize(args) > argidx && args[argidx] == "-vlog-libdir") {
 			for (argidx++; argidx < GetSize(args); argidx++)
-				veri_file::AddYDir(args[argidx].c_str());
+				verific_libdirs.push_back(args[argidx]);
 			goto check_error;
 		}
 
@@ -1847,6 +2158,15 @@ struct VerificPass : public Pass {
 			goto check_error;
 		}
 
+		for (; argidx < GetSize(args); argidx++)
+		{
+			if (args[argidx] == "-work" && argidx+1 < GetSize(args)) {
+				work = args[++argidx];
+				continue;
+			}
+			break;
+		}
+
 		if (GetSize(args) > argidx && (args[argidx] == "-vlog95" || args[argidx] == "-vlog2k" || args[argidx] == "-sv2005" ||
 				args[argidx] == "-sv2009" || args[argidx] == "-sv2012" || args[argidx] == "-sv" || args[argidx] == "-formal"))
 		{
@@ -1869,7 +2189,7 @@ struct VerificPass : public Pass {
 			veri_file::DefineMacro("VERIFIC");
 			veri_file::DefineMacro(args[argidx] == "-formal" ? "FORMAL" : "SYNTHESIS");
 
-			for (argidx++; argidx < GetSize(args) && GetSize(args[argidx]) >= 2 && args[argidx].substr(0, 2) == "-D"; argidx++) {
+			for (argidx++; argidx < GetSize(args) && GetSize(args[argidx]) >= 2 && args[argidx].compare(0, 2, "-D") == 0; argidx++) {
 				std::string name = args[argidx].substr(2);
 				if (args[argidx] == "-D") {
 					if (++argidx >= GetSize(args))
@@ -1886,10 +2206,15 @@ struct VerificPass : public Pass {
 				}
 			}
 
+			for (auto &dir : verific_incdirs)
+				veri_file::AddIncludeDir(dir.c_str());
+			for (auto &dir : verific_libdirs)
+				veri_file::AddYDir(dir.c_str());
+
 			while (argidx < GetSize(args))
 				file_names.Insert(args[argidx++].c_str());
 
-			if (!veri_file::AnalyzeMultipleFiles(&file_names, verilog_mode, "work", veri_file::MFCU))
+			if (!veri_file::AnalyzeMultipleFiles(&file_names, verilog_mode, work.c_str(), veri_file::MFCU))
 					log_cmd_error("Reading Verilog/SystemVerilog sources failed.\n");
 
 			verific_import_pending = true;
@@ -1899,7 +2224,7 @@ struct VerificPass : public Pass {
 		if (GetSize(args) > argidx && args[argidx] == "-vhdl87") {
 			vhdl_file::SetDefaultLibraryPath((proc_share_dirname() + "verific/vhdl_vdbs_1987").c_str());
 			for (argidx++; argidx < GetSize(args); argidx++)
-				if (!vhdl_file::Analyze(args[argidx].c_str(), "work", vhdl_file::VHDL_87))
+				if (!vhdl_file::Analyze(args[argidx].c_str(), work.c_str(), vhdl_file::VHDL_87))
 					log_cmd_error("Reading `%s' in VHDL_87 mode failed.\n", args[argidx].c_str());
 			verific_import_pending = true;
 			goto check_error;
@@ -1908,7 +2233,7 @@ struct VerificPass : public Pass {
 		if (GetSize(args) > argidx && args[argidx] == "-vhdl93") {
 			vhdl_file::SetDefaultLibraryPath((proc_share_dirname() + "verific/vhdl_vdbs_1993").c_str());
 			for (argidx++; argidx < GetSize(args); argidx++)
-				if (!vhdl_file::Analyze(args[argidx].c_str(), "work", vhdl_file::VHDL_93))
+				if (!vhdl_file::Analyze(args[argidx].c_str(), work.c_str(), vhdl_file::VHDL_93))
 					log_cmd_error("Reading `%s' in VHDL_93 mode failed.\n", args[argidx].c_str());
 			verific_import_pending = true;
 			goto check_error;
@@ -1917,7 +2242,7 @@ struct VerificPass : public Pass {
 		if (GetSize(args) > argidx && args[argidx] == "-vhdl2k") {
 			vhdl_file::SetDefaultLibraryPath((proc_share_dirname() + "verific/vhdl_vdbs_1993").c_str());
 			for (argidx++; argidx < GetSize(args); argidx++)
-				if (!vhdl_file::Analyze(args[argidx].c_str(), "work", vhdl_file::VHDL_2K))
+				if (!vhdl_file::Analyze(args[argidx].c_str(), work.c_str(), vhdl_file::VHDL_2K))
 					log_cmd_error("Reading `%s' in VHDL_2K mode failed.\n", args[argidx].c_str());
 			verific_import_pending = true;
 			goto check_error;
@@ -1926,7 +2251,7 @@ struct VerificPass : public Pass {
 		if (GetSize(args) > argidx && (args[argidx] == "-vhdl2008" || args[argidx] == "-vhdl")) {
 			vhdl_file::SetDefaultLibraryPath((proc_share_dirname() + "verific/vhdl_vdbs_2008").c_str());
 			for (argidx++; argidx < GetSize(args); argidx++)
-				if (!vhdl_file::Analyze(args[argidx].c_str(), "work", vhdl_file::VHDL_2008))
+				if (!vhdl_file::Analyze(args[argidx].c_str(), work.c_str(), vhdl_file::VHDL_2008))
 					log_cmd_error("Reading `%s' in VHDL_2008 mode failed.\n", args[argidx].c_str());
 			verific_import_pending = true;
 			goto check_error;
@@ -1937,9 +2262,10 @@ struct VerificPass : public Pass {
 			std::set<Netlist*> nl_todo, nl_done;
 			bool mode_all = false, mode_gates = false, mode_keep = false;
 			bool mode_nosva = false, mode_names = false, mode_verific = false;
-			bool mode_autocover = false;
+			bool mode_autocover = false, mode_fullinit = false;
 			bool flatten = false, extnets = false;
 			string dumpfile;
+			Map parameters(STRING_HASH);
 
 			for (argidx++; argidx < GetSize(args); argidx++) {
 				if (args[argidx] == "-all") {
@@ -1966,6 +2292,10 @@ struct VerificPass : public Pass {
 					mode_nosva = true;
 					continue;
 				}
+				if (args[argidx] == "-L" && argidx+1 < GetSize(args)) {
+					verific_sva_fsm_limit = atoi(args[++argidx].c_str());
+					continue;
+				}
 				if (args[argidx] == "-n") {
 					mode_names = true;
 					continue;
@@ -1974,6 +2304,19 @@ struct VerificPass : public Pass {
 					mode_autocover = true;
 					continue;
 				}
+				if (args[argidx] == "-fullinit") {
+					mode_fullinit = true;
+					continue;
+				}
+				if (args[argidx] == "-chparam"  && argidx+2 < GetSize(args)) {
+					const std::string &key = args[++argidx];
+					const std::string &value = args[++argidx];
+					unsigned new_insertion = parameters.Insert(key.c_str(), value.c_str(),
+									           1 /* force_overwrite */);
+					if (!new_insertion)
+						log_warning_noprefix("-chparam %s already specified: overwriting.\n", key.c_str());
+					continue;
+				}
 				if (args[argidx] == "-V") {
 					mode_verific = true;
 					continue;
@@ -1993,98 +2336,56 @@ struct VerificPass : public Pass {
 				break;
 			}
 
-			if (argidx > GetSize(args) && args[argidx].substr(0, 1) == "-")
+			if (argidx > GetSize(args) && args[argidx].compare(0, 1, "-") == 0)
 				cmd_error(args, argidx, "unknown option");
 
 			if (mode_all)
 			{
-#if 0
-				log("Running veri_file::ElaborateAll().\n");
-				if (!veri_file::ElaborateAll())
-					log_cmd_error("Elaboration of Verilog modules failed.\n");
-
-				log("Running vhdl_file::ElaborateAll().\n");
-				if (!vhdl_file::ElaborateAll())
-					log_cmd_error("Elaboration of VHDL modules failed.\n");
-
-				Library *lib = Netlist::PresentDesign()->Owner()->Owner();
-
-				if (argidx == GetSize(args))
-				{
-					MapIter iter;
-					char *iter_name;
-					Verific::Cell *iter_cell;
-
-					FOREACH_MAP_ITEM(lib->GetCells(), iter, &iter_name, &iter_cell) {
-						if (*iter_name != '$')
-							nl_todo.insert(iter_cell->GetFirstNetlist());
-					}
-				}
-				else
-				{
-					for (; argidx < GetSize(args); argidx++)
-					{
-						Verific::Cell *cell = lib->GetCell(args[argidx].c_str());
-
-						if (cell == nullptr)
-							log_cmd_error("Module not found: %s\n", args[argidx].c_str());
-
-						nl_todo.insert(cell->GetFirstNetlist());
-						cell->GetFirstNetlist()->SetPresentDesign();
-					}
-				}
-#else
 				log("Running hier_tree::ElaborateAll().\n");
 
-				VhdlLibrary *vhdl_lib = vhdl_file::GetLibrary("work", 1);
-				VeriLibrary *veri_lib = veri_file::GetLibrary("work", 1);
+				VhdlLibrary *vhdl_lib = vhdl_file::GetLibrary(work.c_str(), 1);
+				VeriLibrary *veri_lib = veri_file::GetLibrary(work.c_str(), 1);
 
 				Array veri_libs, vhdl_libs;
 				if (vhdl_lib) vhdl_libs.InsertLast(vhdl_lib);
 				if (veri_lib) veri_libs.InsertLast(veri_lib);
 
-				Array *netlists = hier_tree::ElaborateAll(&veri_libs, &vhdl_libs);
+				Array *netlists = hier_tree::ElaborateAll(&veri_libs, &vhdl_libs, &parameters);
 				Netlist *nl;
 				int i;
 
 				FOREACH_ARRAY_ITEM(netlists, i, nl)
 					nl_todo.insert(nl);
 				delete netlists;
-#endif
 			}
 			else
 			{
 				if (argidx == GetSize(args))
 					log_cmd_error("No top module specified.\n");
 
-#if 0
-				for (; argidx < GetSize(args); argidx++) {
-					if (veri_file::GetModule(args[argidx].c_str())) {
-						log("Running veri_file::Elaborate(\"%s\").\n", args[argidx].c_str());
-						if (!veri_file::Elaborate(args[argidx].c_str()))
-							log_cmd_error("Elaboration of top module `%s' failed.\n", args[argidx].c_str());
-						nl_todo.insert(Netlist::PresentDesign());
-					} else {
-						log("Running vhdl_file::Elaborate(\"%s\").\n", args[argidx].c_str());
-						if (!vhdl_file::Elaborate(args[argidx].c_str()))
-							log_cmd_error("Elaboration of top module `%s' failed.\n", args[argidx].c_str());
-						nl_todo.insert(Netlist::PresentDesign());
-					}
-				}
-#else
 				Array veri_modules, vhdl_units;
 				for (; argidx < GetSize(args); argidx++)
 				{
 					const char *name = args[argidx].c_str();
+					VeriLibrary* veri_lib = veri_file::GetLibrary(work.c_str(), 1);
+
+					if (veri_lib) {
+						VeriModule *veri_module = veri_lib->GetModule(name, 1);
+						if (veri_module) {
+							log("Adding Verilog module '%s' to elaboration queue.\n", name);
+							veri_modules.InsertLast(veri_module);
+							continue;
+						}
 
-					VeriModule *veri_module = veri_file::GetModule(name);
-					if (veri_module) {
-						log("Adding Verilog module '%s' to elaboration queue.\n", name);
-						veri_modules.InsertLast(veri_module);
-						continue;
+						// Also elaborate all root modules since they may contain bind statements
+						MapIter mi;
+						FOREACH_VERILOG_MODULE_IN_LIBRARY(veri_lib, mi, veri_module) {
+							if (!veri_module->IsRootModule()) continue;
+							veri_modules.InsertLast(veri_module);
+						}
 					}
 
-					VhdlLibrary *vhdl_lib = vhdl_file::GetLibrary("work", 1);
+					VhdlLibrary *vhdl_lib = vhdl_file::GetLibrary(work.c_str(), 1);
 					VhdlDesignUnit *vhdl_unit = vhdl_lib->GetPrimUnit(name);
 					if (vhdl_unit) {
 						log("Adding VHDL unit '%s' to elaboration queue.\n", name);
@@ -2096,14 +2397,15 @@ struct VerificPass : public Pass {
 				}
 
 				log("Running hier_tree::Elaborate().\n");
-				Array *netlists = hier_tree::Elaborate(&veri_modules, &vhdl_units);
+				Array *netlists = hier_tree::Elaborate(&veri_modules, &vhdl_units, &parameters);
 				Netlist *nl;
 				int i;
 
-				FOREACH_ARRAY_ITEM(netlists, i, nl)
+				FOREACH_ARRAY_ITEM(netlists, i, nl) {
+					nl->AddAtt(new Att(" \\top", NULL));
 					nl_todo.insert(nl);
+				}
 				delete netlists;
-#endif
 			}
 
 			if (!verific_error_msg.empty())
@@ -2129,7 +2431,7 @@ struct VerificPass : public Pass {
 				Netlist *nl = *nl_todo.begin();
 				if (nl_done.count(nl) == 0) {
 					VerificImporter importer(mode_gates, mode_keep, mode_nosva,
-							mode_names, mode_verific, mode_autocover);
+							mode_names, mode_verific, mode_autocover, mode_fullinit);
 					importer.import_netlist(design, nl, nl_todo);
 				}
 				nl_todo.erase(nl);
@@ -2139,6 +2441,8 @@ struct VerificPass : public Pass {
 			veri_file::Reset();
 			vhdl_file::Reset();
 			Libset::Reset();
+			verific_incdirs.clear();
+			verific_libdirs.clear();
 			verific_import_pending = false;
 			goto check_error;
 		}
@@ -2151,7 +2455,7 @@ struct VerificPass : public Pass {
 
 	}
 #else /* YOSYS_ENABLE_VERIFIC */
-	virtual void execute(std::vector<std::string>, RTLIL::Design *) {
+	void execute(std::vector<std::string>, RTLIL::Design *) YS_OVERRIDE {
 		log_cmd_error("This version of Yosys is built without Verific support.\n");
 	}
 #endif
@@ -2159,7 +2463,7 @@ struct VerificPass : public Pass {
 
 struct ReadPass : public Pass {
 	ReadPass() : Pass("read", "load HDL designs") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -2186,27 +2490,54 @@ struct ReadPass : public Pass {
 		log("\n");
 		log("Unset global Verilog/SystemVerilog defines.\n");
 		log("\n");
+		log("\n");
+		log("    read -incdir <directory>\n");
+		log("\n");
+		log("Add directory to global Verilog/SystemVerilog include directories.\n");
+		log("\n");
+		log("\n");
+		log("    read -verific\n");
+		log("    read -noverific\n");
+		log("\n");
+		log("Subsequent calls to 'read' will either use or not use Verific. Calling 'read'\n");
+		log("with -verific will result in an error on Yosys binaries that are built without\n");
+		log("Verific support. The default is to use Verific if it is available.\n");
+		log("\n");
 	}
-	virtual void execute(std::vector<std::string> args, RTLIL::Design *design)
+	void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
 	{
-		if (args.size() < 2)
+#ifdef YOSYS_ENABLE_VERIFIC
+		static bool verific_available = !check_noverific_env();
+#else
+		static bool verific_available = false;
+#endif
+		static bool use_verific = verific_available;
+
+		if (args.size() < 2 || args[1][0] != '-')
 			log_cmd_error("Missing mode parameter.\n");
 
+		if (args[1] == "-verific" || args[1] == "-noverific") {
+			if (args.size() != 2)
+				log_cmd_error("Additional arguments to -verific/-noverific.\n");
+			if (args[1] == "-verific") {
+				if (!verific_available)
+					log_cmd_error("This version of Yosys is built without Verific support.\n");
+				use_verific = true;
+			} else {
+				use_verific = false;
+			}
+			return;
+		}
+
 		if (args.size() < 3)
 			log_cmd_error("Missing file name parameter.\n");
 
-#ifdef YOSYS_ENABLE_VERIFIC
-		bool use_verific = !check_noverific_env();
-#else
-		bool use_verific = false;
-#endif
-
 		if (args[1] == "-vlog95" || args[1] == "-vlog2k") {
 			if (use_verific) {
 				args[0] = "verific";
 			} else {
 				args[0] = "read_verilog";
-				args.erase(args.begin()+1, args.begin()+2);
+				args[1] = "-defer";
 			}
 			Pass::call(design, args);
 			return;
@@ -2220,6 +2551,7 @@ struct ReadPass : public Pass {
 				if (args[1] == "-formal")
 					args.insert(args.begin()+1, std::string());
 				args[1] = "-sv";
+				args.insert(args.begin()+1, "-defer");
 			}
 			Pass::call(design, args);
 			return;
@@ -2263,6 +2595,20 @@ struct ReadPass : public Pass {
 			return;
 		}
 
+		if (args[1] == "-incdir") {
+			if (use_verific) {
+				args[0] = "verific";
+				args[1] = "-vlog-incdir";
+				Pass::call(design, args);
+			}
+			args[0] = "verilog_defaults";
+			args[1] = "-add";
+			for (int i = 2; i < GetSize(args); i++)
+				args[i] = "-I" + args[i];
+			Pass::call(design, args);
+			return;
+		}
+
 		log_cmd_error("Missing or unsupported mode parameter.\n");
 	}
 } ReadPass;
diff --git a/frontends/verific/verific.h b/frontends/verific/verific.h
index cbd9314db..5cbd78f7b 100644
--- a/frontends/verific/verific.h
+++ b/frontends/verific/verific.h
@@ -26,7 +26,7 @@ YOSYS_NAMESPACE_BEGIN
 extern int verific_verbose;
 
 extern bool verific_import_pending;
-extern void verific_import(Design *design, std::string top = std::string());
+extern void verific_import(Design *design, const std::map<std::string,std::string> &parameters, std::string top = std::string());
 
 extern pool<int> verific_sva_prims;
 
@@ -72,12 +72,13 @@ struct VerificImporter
 	pool<Verific::Net*, hash_ptr_ops> any_all_nets;
 
 	bool mode_gates, mode_keep, mode_nosva, mode_names, mode_verific;
-	bool mode_autocover;
+	bool mode_autocover, mode_fullinit;
 
-	VerificImporter(bool mode_gates, bool mode_keep, bool mode_nosva, bool mode_names, bool mode_verific, bool mode_autocover);
+	VerificImporter(bool mode_gates, bool mode_keep, bool mode_nosva, bool mode_names, bool mode_verific, bool mode_autocover, bool mode_fullinit);
 
 	RTLIL::SigBit net_map_at(Verific::Net *net);
 
+	RTLIL::IdString new_verific_id(Verific::DesignObj *obj);
 	void import_attributes(dict<RTLIL::IdString, RTLIL::Const> &attributes, Verific::DesignObj *obj);
 
 	RTLIL::SigSpec operatorInput(Verific::Instance *inst);
@@ -101,6 +102,8 @@ void verific_import_sva_cover(VerificImporter *importer, Verific::Instance *inst
 void verific_import_sva_trigger(VerificImporter *importer, Verific::Instance *inst);
 bool verific_is_sva_net(VerificImporter *importer, Verific::Net *net);
 
+extern int verific_sva_fsm_limit;
+
 YOSYS_NAMESPACE_END
 
 #endif
diff --git a/frontends/verific/verificsva.cc b/frontends/verific/verificsva.cc
index 8e985c3a6..909e9b4f1 100644
--- a/frontends/verific/verificsva.cc
+++ b/frontends/verific/verificsva.cc
@@ -357,7 +357,7 @@ struct SvaFsm
 		for (int i = 0; i < GetSize(nodes); i++)
 		{
 			if (next_state_sig[i] != State::S0) {
-				clocking.addDff(NEW_ID, next_state_sig[i], state_wire[i], Const(0, 1));
+				clocking.addDff(NEW_ID, next_state_sig[i], state_wire[i], State::S0);
 			} else {
 				module->connect(state_wire[i], State::S0);
 			}
@@ -466,13 +466,14 @@ struct SvaFsm
 
 		dnode.ctrl.sort_and_unify();
 
-		if (GetSize(dnode.ctrl) > 16) {
+		if (GetSize(dnode.ctrl) > verific_sva_fsm_limit) {
 			if (verific_verbose >= 2) {
 				log("    detected state explosion in DFSM generation:\n");
 				dump();
 				log("      ctrl signal: %s\n", log_signal(dnode.ctrl));
 			}
-			log_error("SVA DFSM state ctrl signal has %d (>16) bits. Stopping to prevent exponential design size explosion.\n", GetSize(dnode.ctrl));
+			log_error("SVA DFSM state ctrl signal has %d (>%d) bits. Stopping to prevent exponential design size explosion.\n",
+					GetSize(dnode.ctrl), verific_sva_fsm_limit);
 		}
 
 		for (int i = 0; i < (1 << GetSize(dnode.ctrl)); i++)
@@ -826,9 +827,9 @@ struct SvaFsm
 
 			for (auto &it : nodes[i].edges) {
 				if (it.second != State::S1)
-					log("          egde %s -> %d\n", log_signal(it.second), it.first);
+					log("          edge %s -> %d\n", log_signal(it.second), it.first);
 				else
-					log("          egde -> %d\n", it.first);
+					log("          edge -> %d\n", it.first);
 			}
 
 			for (auto &it : nodes[i].links) {
@@ -855,9 +856,9 @@ struct SvaFsm
 
 			for (auto &it : unodes[i].edges) {
 				if (!it.second.empty())
-					log("          egde %s -> %d\n", log_signal(it.second), it.first);
+					log("          edge %s -> %d\n", log_signal(it.second), it.first);
 				else
-					log("          egde -> %d\n", it.first);
+					log("          edge -> %d\n", it.first);
 			}
 
 			for (auto &ctrl : unodes[i].accept) {
@@ -1517,9 +1518,11 @@ struct VerificSvaImporter
 
 			Instance *consequent_inst = net_to_ast_driver(consequent_net);
 
-			if (consequent_inst->Type() != PRIM_SVA_S_EVENTUALLY && consequent_inst->Type() != PRIM_SVA_EVENTUALLY) {
+			if (consequent_inst == nullptr)
+				return false;
+
+			if (consequent_inst->Type() != PRIM_SVA_S_EVENTUALLY && consequent_inst->Type() != PRIM_SVA_EVENTUALLY)
 				return false;
-			}
 
 			if (mode_cover || mode_trigger)
 				parser_error(consequent_inst);
@@ -1663,7 +1666,20 @@ struct VerificSvaImporter
 				log("  importing SVA property at root cell %s (%s) at %s:%d.\n", root->Name(), root->View()->Owner()->Name(),
 						LineFile::GetFileName(root->Linefile()), LineFile::GetLineNo(root->Linefile()));
 
-			RTLIL::IdString root_name = module->uniquify(importer->mode_names || root->IsUserDeclared() ? RTLIL::escape_id(root->Name()) : NEW_ID);
+			bool is_user_declared = root->IsUserDeclared();
+
+			// FIXME
+			if (!is_user_declared) {
+				const char *name = root->Name();
+				for (int i = 0; name[i]; i++) {
+					if (i ? (name[i] < '0' || name[i] > '9') : (name[i] != 'i')) {
+						is_user_declared = true;
+						break;
+					}
+				}
+			}
+
+			RTLIL::IdString root_name = module->uniquify(importer->mode_names || is_user_declared ? RTLIL::escape_id(root->Name()) : NEW_ID);
 
 			// parse SVA sequence into trigger signal
 
diff --git a/frontends/verilog/.gitignore b/frontends/verilog/.gitignore
index 1d4ae9e5c..aadbcdcdd 100644
--- a/frontends/verilog/.gitignore
+++ b/frontends/verilog/.gitignore
@@ -1,4 +1,4 @@
 verilog_lexer.cc
 verilog_parser.output
 verilog_parser.tab.cc
-verilog_parser.tab.h
+verilog_parser.tab.hh
diff --git a/frontends/verilog/Makefile.inc b/frontends/verilog/Makefile.inc
index a06c1d5ab..6a8462b41 100644
--- a/frontends/verilog/Makefile.inc
+++ b/frontends/verilog/Makefile.inc
@@ -1,20 +1,21 @@
 
 GENFILES += frontends/verilog/verilog_parser.tab.cc
-GENFILES += frontends/verilog/verilog_parser.tab.h
+GENFILES += frontends/verilog/verilog_parser.tab.hh
 GENFILES += frontends/verilog/verilog_parser.output
 GENFILES += frontends/verilog/verilog_lexer.cc
 
 frontends/verilog/verilog_parser.tab.cc: frontends/verilog/verilog_parser.y
 	$(Q) mkdir -p $(dir $@)
-	$(P) $(BISON) -d -r all -b frontends/verilog/verilog_parser $<
-	$(Q) mv frontends/verilog/verilog_parser.tab.c frontends/verilog/verilog_parser.tab.cc
+	$(P) $(BISON) -o $@ -d -r all -b frontends/verilog/verilog_parser $<
 
-frontends/verilog/verilog_parser.tab.h: frontends/verilog/verilog_parser.tab.cc
+frontends/verilog/verilog_parser.tab.hh: frontends/verilog/verilog_parser.tab.cc
 
 frontends/verilog/verilog_lexer.cc: frontends/verilog/verilog_lexer.l
 	$(Q) mkdir -p $(dir $@)
 	$(P) flex -o frontends/verilog/verilog_lexer.cc $<
 
+frontends/verilog/verilog_parser.tab.o: CXXFLAGS += -DYYMAXDEPTH=10000000
+
 OBJS += frontends/verilog/verilog_parser.tab.o
 OBJS += frontends/verilog/verilog_lexer.o
 OBJS += frontends/verilog/preproc.o
diff --git a/frontends/verilog/const2ast.cc b/frontends/verilog/const2ast.cc
index 4a58357bf..49281f7e7 100644
--- a/frontends/verilog/const2ast.cc
+++ b/frontends/verilog/const2ast.cc
@@ -49,8 +49,7 @@ static int my_decimal_div_by_two(std::vector<uint8_t> &digits)
 	int carry = 0;
 	for (size_t i = 0; i < digits.size(); i++) {
 		if (digits[i] >= 10)
-			log_error("Invalid use of [a-fxz?] in decimal constant at %s:%d.\n",
-				current_filename.c_str(), get_line_num());
+			log_file_error(current_filename, get_line_num(), "Invalid use of [a-fxz?] in decimal constant.\n");
 		digits[i] += carry * 10;
 		carry = digits[i] % 2;
 		digits[i] /= 2;
@@ -72,7 +71,7 @@ static int my_ilog2(int x)
 }
 
 // parse a binary, decimal, hexadecimal or octal number with support for special bits ('x', 'z' and '?')
-static void my_strtobin(std::vector<RTLIL::State> &data, const char *str, int len_in_bits, int base, char case_type)
+static void my_strtobin(std::vector<RTLIL::State> &data, const char *str, int len_in_bits, int base, char case_type, bool is_unsized)
 {
 	// all digits in string (MSB at index 0)
 	std::vector<uint8_t> digits;
@@ -86,10 +85,8 @@ static void my_strtobin(std::vector<RTLIL::State> &data, const char *str, int le
 			digits.push_back(10 + *str - 'A');
 		else if (*str == 'x' || *str == 'X')
 			digits.push_back(0xf0);
-		else if (*str == 'z' || *str == 'Z')
+		else if (*str == 'z' || *str == 'Z' || *str == '?')
 			digits.push_back(0xf1);
-		else if (*str == '?')
-			digits.push_back(0xf2);
 		str++;
 	}
 
@@ -100,42 +97,43 @@ static void my_strtobin(std::vector<RTLIL::State> &data, const char *str, int le
 
 	if (base == 10) {
 		while (!digits.empty())
-			data.push_back(my_decimal_div_by_two(digits) ? RTLIL::S1 : RTLIL::S0);
+			data.push_back(my_decimal_div_by_two(digits) ? State::S1 : State::S0);
 	} else {
 		int bits_per_digit = my_ilog2(base-1);
 		for (auto it = digits.rbegin(), e = digits.rend(); it != e; it++) {
 			if (*it > (base-1) && *it < 0xf0)
-				log_error("Digit larger than %d used in in base-%d constant at %s:%d.\n",
-					base-1, base, current_filename.c_str(), get_line_num());
+				log_file_error(current_filename, get_line_num(), "Digit larger than %d used in in base-%d constant.\n",
+					       base-1, base);
 			for (int i = 0; i < bits_per_digit; i++) {
 				int bitmask = 1 << i;
 				if (*it == 0xf0)
 					data.push_back(case_type == 'x' ? RTLIL::Sa : RTLIL::Sx);
 				else if (*it == 0xf1)
 					data.push_back(case_type == 'x' || case_type == 'z' ? RTLIL::Sa : RTLIL::Sz);
-				else if (*it == 0xf2)
-					data.push_back(RTLIL::Sa);
 				else
-					data.push_back((*it & bitmask) ? RTLIL::S1 : RTLIL::S0);
+					data.push_back((*it & bitmask) ? State::S1 : State::S0);
 			}
 		}
 	}
 
 	int len = GetSize(data);
-	RTLIL::State msb = data.empty() ? RTLIL::S0 : data.back();
+	RTLIL::State msb = data.empty() ? State::S0 : data.back();
 
 	if (len_in_bits < 0) {
 		if (len < 32)
-			data.resize(32, msb == RTLIL::S0 || msb == RTLIL::S1 ? RTLIL::S0 : msb);
+			data.resize(32, msb == State::S0 || msb == State::S1 ? RTLIL::S0 : msb);
 		return;
 	}
 
+	if (is_unsized && (len > len_in_bits))
+		log_file_error(current_filename, get_line_num(), "Unsized constant must have width of 1 bit, but have %d bits!\n", len);
+
 	for (len = len - 1; len >= 0; len--)
-		if (data[len] == RTLIL::S1)
+		if (data[len] == State::S1)
 			break;
-	if (msb == RTLIL::S0 || msb == RTLIL::S1) {
+	if (msb == State::S0 || msb == State::S1) {
 		len += 1;
-		data.resize(len_in_bits, RTLIL::S0);
+		data.resize(len_in_bits, State::S0);
 	} else {
 		len += 2;
 		data.resize(len_in_bits, msb);
@@ -151,7 +149,7 @@ AstNode *VERILOG_FRONTEND::const2ast(std::string code, char case_type, bool warn
 {
 	if (warn_z) {
 		AstNode *ret = const2ast(code, case_type);
-		if (std::find(ret->bits.begin(), ret->bits.end(), RTLIL::State::Sz) != ret->bits.end())
+		if (ret != nullptr && std::find(ret->bits.begin(), ret->bits.end(), RTLIL::State::Sz) != ret->bits.end())
 			log_warning("Yosys has only limited support for tri-state logic at the moment. (%s:%d)\n",
 				current_filename.c_str(), get_line_num());
 		return ret;
@@ -167,7 +165,7 @@ AstNode *VERILOG_FRONTEND::const2ast(std::string code, char case_type, bool warn
 		for (int i = 0; i < len; i++) {
 			unsigned char ch = str[len - i];
 			for (int j = 0; j < 8; j++) {
-				data.push_back((ch & 1) ? RTLIL::S1 : RTLIL::S0);
+				data.push_back((ch & 1) ? State::S1 : State::S0);
 				ch = ch >> 1;
 			}
 		}
@@ -187,9 +185,9 @@ AstNode *VERILOG_FRONTEND::const2ast(std::string code, char case_type, bool warn
 	// Simple base-10 integer
 	if (*endptr == 0) {
 		std::vector<RTLIL::State> data;
-		my_strtobin(data, str, -1, 10, case_type);
-		if (data.back() == RTLIL::S1)
-			data.push_back(RTLIL::S0);
+		my_strtobin(data, str, -1, 10, case_type, false);
+		if (data.back() == State::S1)
+			data.push_back(State::S0);
 		return AstNode::mkconst_bits(data, true);
 	}
 
@@ -197,12 +195,13 @@ AstNode *VERILOG_FRONTEND::const2ast(std::string code, char case_type, bool warn
 	if (str == endptr)
 		len_in_bits = -1;
 
-	// The "<bits>'s?[bodhBODH]<digits>" syntax
+	// The "<bits>'[sS]?[bodhBODH]<digits>" syntax
 	if (*endptr == '\'')
 	{
 		std::vector<RTLIL::State> data;
 		bool is_signed = false;
-		if (*(endptr+1) == 's') {
+		bool is_unsized = len_in_bits < 0;
+		if (*(endptr+1) == 's' || *(endptr+1) == 'S') {
 			is_signed = true;
 			endptr++;
 		}
@@ -210,32 +209,37 @@ AstNode *VERILOG_FRONTEND::const2ast(std::string code, char case_type, bool warn
 		{
 		case 'b':
 		case 'B':
-			my_strtobin(data, endptr+2, len_in_bits, 2, case_type);
+			my_strtobin(data, endptr+2, len_in_bits, 2, case_type, is_unsized);
 			break;
 		case 'o':
 		case 'O':
-			my_strtobin(data, endptr+2, len_in_bits, 8, case_type);
+			my_strtobin(data, endptr+2, len_in_bits, 8, case_type, is_unsized);
 			break;
 		case 'd':
 		case 'D':
-			my_strtobin(data, endptr+2, len_in_bits, 10, case_type);
+			my_strtobin(data, endptr+2, len_in_bits, 10, case_type, is_unsized);
 			break;
 		case 'h':
 		case 'H':
-			my_strtobin(data, endptr+2, len_in_bits, 16, case_type);
+			my_strtobin(data, endptr+2, len_in_bits, 16, case_type, is_unsized);
 			break;
 		default:
-			return NULL;
+			char next_char = char(tolower(*(endptr+1)));
+			if (next_char == '0' || next_char == '1' || next_char == 'x' || next_char == 'z') {
+				is_unsized = true;
+				my_strtobin(data, endptr+1, 1, 2, case_type, is_unsized);
+			} else {
+				return NULL;
+			}
 		}
 		if (len_in_bits < 0) {
-			if (is_signed && data.back() == RTLIL::S1)
-				data.push_back(RTLIL::S0);
+			if (is_signed && data.back() == State::S1)
+				data.push_back(State::S0);
 		}
-		return AstNode::mkconst_bits(data, is_signed);
+		return AstNode::mkconst_bits(data, is_signed, is_unsized);
 	}
 
 	return NULL;
 }
 
 YOSYS_NAMESPACE_END
-
diff --git a/frontends/verilog/verilog_frontend.cc b/frontends/verilog/verilog_frontend.cc
index 505c94619..0e2bead6f 100644
--- a/frontends/verilog/verilog_frontend.cc
+++ b/frontends/verilog/verilog_frontend.cc
@@ -42,14 +42,14 @@ static std::list<std::vector<std::string>> verilog_defaults_stack;
 static void error_on_dpi_function(AST::AstNode *node)
 {
 	if (node->type == AST::AST_DPI_FUNCTION)
-		log_error("Found DPI function %s at %s:%d.\n", node->str.c_str(), node->filename.c_str(), node->linenum);
+		log_file_error(node->filename, node->linenum, "Found DPI function %s.\n", node->str.c_str());
 	for (auto child : node->children)
 		error_on_dpi_function(child);
 }
 
 struct VerilogFrontend : public Frontend {
 	VerilogFrontend() : Frontend("verilog", "read modules from Verilog file") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -66,19 +66,37 @@ struct VerilogFrontend : public Frontend {
 		log("        enable support for SystemVerilog assertions and some Yosys extensions\n");
 		log("        replace the implicit -D SYNTHESIS with -D FORMAL\n");
 		log("\n");
+		log("    -noassert\n");
+		log("        ignore assert() statements\n");
+		log("\n");
+		log("    -noassume\n");
+		log("        ignore assume() statements\n");
+		log("\n");
 		log("    -norestrict\n");
-		log("        ignore restrict() assertions\n");
+		log("        ignore restrict() statements\n");
 		log("\n");
 		log("    -assume-asserts\n");
 		log("        treat all assert() statements like assume() statements\n");
 		log("\n");
+		log("    -assert-assumes\n");
+		log("        treat all assume() statements like assert() statements\n");
+		log("\n");
+		log("    -debug\n");
+		log("        alias for -dump_ast1 -dump_ast2 -dump_vlog1 -dump_vlog2 -yydebug\n");
+		log("\n");
 		log("    -dump_ast1\n");
 		log("        dump abstract syntax tree (before simplification)\n");
 		log("\n");
 		log("    -dump_ast2\n");
 		log("        dump abstract syntax tree (after simplification)\n");
 		log("\n");
-		log("    -dump_vlog\n");
+		log("    -no_dump_ptr\n");
+		log("        do not include hex memory addresses in dump (easier to diff dumps)\n");
+		log("\n");
+		log("    -dump_vlog1\n");
+		log("        dump ast as Verilog code (before simplification)\n");
+		log("\n");
+		log("    -dump_vlog2\n");
 		log("        dump ast as Verilog code (after simplification)\n");
 		log("\n");
 		log("    -dump_rtlil\n");
@@ -127,8 +145,21 @@ struct VerilogFrontend : public Frontend {
 		log("    -nodpi\n");
 		log("        disable DPI-C support\n");
 		log("\n");
+		log("    -noblackbox\n");
+		log("        do not automatically add a (* blackbox *) attribute to an\n");
+		log("        empty module.\n");
+		log("\n");
 		log("    -lib\n");
 		log("        only create empty blackbox modules. This implies -DBLACKBOX.\n");
+		log("        modules with the (* whitebox *) attribute will be preserved.\n");
+		log("        (* lib_whitebox *) will be treated like (* whitebox *).\n");
+		log("\n");
+		log("    -nowb\n");
+		log("        delete (* whitebox *) and (* lib_whitebox *) attributes from\n");
+		log("        all modules.\n");
+		log("\n");
+		log("    -specify\n");
+		log("        parse and import specify blocks\n");
 		log("\n");
 		log("    -noopt\n");
 		log("        don't perform basic optimizations (such as const folding) in the\n");
@@ -137,6 +168,9 @@ struct VerilogFrontend : public Frontend {
 		log("    -icells\n");
 		log("        interpret cell types starting with '$' as internal cell types\n");
 		log("\n");
+		log("    -pwires\n");
+		log("        add a wire for each module parameter\n");
+		log("\n");
 		log("    -nooverwrite\n");
 		log("        ignore re-definitions of modules. (the default behavior is to\n");
 		log("        create an error message if the existing module is not a black box\n");
@@ -180,11 +214,13 @@ struct VerilogFrontend : public Frontend {
 		log("supported by the Yosys Verilog front-end.\n");
 		log("\n");
 	}
-	virtual void execute(std::istream *&f, std::string filename, std::vector<std::string> args, RTLIL::Design *design)
+	void execute(std::istream *&f, std::string filename, std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
 	{
 		bool flag_dump_ast1 = false;
 		bool flag_dump_ast2 = false;
-		bool flag_dump_vlog = false;
+		bool flag_no_dump_ptr = false;
+		bool flag_dump_vlog1 = false;
+		bool flag_dump_vlog2 = false;
 		bool flag_dump_rtlil = false;
 		bool flag_nolatches = false;
 		bool flag_nomeminit = false;
@@ -195,9 +231,12 @@ struct VerilogFrontend : public Frontend {
 		bool flag_nodpi = false;
 		bool flag_noopt = false;
 		bool flag_icells = false;
+		bool flag_pwires = false;
 		bool flag_nooverwrite = false;
 		bool flag_overwrite = false;
 		bool flag_defer = false;
+		bool flag_noblackbox = false;
+		bool flag_nowb = false;
 		std::map<std::string, std::string> defines_map;
 		std::list<std::string> include_dirs;
 		std::list<std::string> attributes;
@@ -208,10 +247,9 @@ struct VerilogFrontend : public Frontend {
 		norestrict_mode = false;
 		assume_asserts_mode = false;
 		lib_mode = false;
+		specify_mode = false;
 		default_nettype_wire = true;
 
-		log_header(design, "Executing Verilog-2005 frontend.\n");
-
 		args.insert(args.begin()+1, verilog_defaults.begin(), verilog_defaults.end());
 
 		size_t argidx;
@@ -225,6 +263,14 @@ struct VerilogFrontend : public Frontend {
 				formal_mode = true;
 				continue;
 			}
+			if (arg == "-noassert") {
+				noassert_mode = true;
+				continue;
+			}
+			if (arg == "-noassume") {
+				noassume_mode = true;
+				continue;
+			}
 			if (arg == "-norestrict") {
 				norestrict_mode = true;
 				continue;
@@ -233,6 +279,18 @@ struct VerilogFrontend : public Frontend {
 				assume_asserts_mode = true;
 				continue;
 			}
+			if (arg == "-assert-assumes") {
+				assert_assumes_mode = true;
+				continue;
+			}
+			if (arg == "-debug") {
+				flag_dump_ast1 = true;
+				flag_dump_ast2 = true;
+				flag_dump_vlog1 = true;
+				flag_dump_vlog2 = true;
+				frontend_verilog_yydebug = true;
+				continue;
+			}
 			if (arg == "-dump_ast1") {
 				flag_dump_ast1 = true;
 				continue;
@@ -241,8 +299,16 @@ struct VerilogFrontend : public Frontend {
 				flag_dump_ast2 = true;
 				continue;
 			}
-			if (arg == "-dump_vlog") {
-				flag_dump_vlog = true;
+			if (arg == "-no_dump_ptr") {
+				flag_no_dump_ptr = true;
+				continue;
+			}
+			if (arg == "-dump_vlog1") {
+				flag_dump_vlog1 = true;
+				continue;
+			}
+			if (arg == "-dump_vlog2") {
+				flag_dump_vlog2 = true;
 				continue;
 			}
 			if (arg == "-dump_rtlil") {
@@ -281,11 +347,23 @@ struct VerilogFrontend : public Frontend {
 				flag_nodpi = true;
 				continue;
 			}
+			if (arg == "-noblackbox") {
+				flag_noblackbox = true;
+				continue;
+			}
 			if (arg == "-lib") {
 				lib_mode = true;
 				defines_map["BLACKBOX"] = string();
 				continue;
 			}
+			if (arg == "-nowb") {
+				flag_nowb = true;
+				continue;
+			}
+			if (arg == "-specify") {
+				specify_mode = true;
+				continue;
+			}
 			if (arg == "-noopt") {
 				flag_noopt = true;
 				continue;
@@ -294,6 +372,10 @@ struct VerilogFrontend : public Frontend {
 				flag_icells = true;
 				continue;
 			}
+			if (arg == "-pwires") {
+				flag_pwires = true;
+				continue;
+			}
 			if (arg == "-ignore_redef" || arg == "-nooverwrite") {
 				flag_nooverwrite = true;
 				flag_overwrite = false;
@@ -347,6 +429,8 @@ struct VerilogFrontend : public Frontend {
 		}
 		extra_args(f, filename, args, argidx);
 
+		log_header(design, "Executing Verilog-2005 frontend: %s\n", filename.c_str());
+
 		log("Parsing %s%s input from `%s' to AST representation.\n",
 				formal_mode ? "formal " : "", sv_mode ? "SystemVerilog" : "Verilog", filename.c_str());
 
@@ -381,7 +465,8 @@ struct VerilogFrontend : public Frontend {
 		if (flag_nodpi)
 			error_on_dpi_function(current_ast);
 
-		AST::process(design, current_ast, flag_dump_ast1, flag_dump_ast2, flag_dump_vlog, flag_dump_rtlil, flag_nolatches, flag_nomeminit, flag_nomem2reg, flag_mem2reg, lib_mode, flag_noopt, flag_icells, flag_nooverwrite, flag_overwrite, flag_defer, default_nettype_wire);
+		AST::process(design, current_ast, flag_dump_ast1, flag_dump_ast2, flag_no_dump_ptr, flag_dump_vlog1, flag_dump_vlog2, flag_dump_rtlil, flag_nolatches,
+				flag_nomeminit, flag_nomem2reg, flag_mem2reg, flag_noblackbox, lib_mode, flag_nowb, flag_noopt, flag_icells, flag_pwires, flag_nooverwrite, flag_overwrite, flag_defer, default_nettype_wire);
 
 		if (!flag_nopp)
 			delete lexin;
@@ -395,7 +480,7 @@ struct VerilogFrontend : public Frontend {
 
 struct VerilogDefaults : public Pass {
 	VerilogDefaults() : Pass("verilog_defaults", "set default options for read_verilog") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -416,7 +501,7 @@ struct VerilogDefaults : public Pass {
 		log("not imply -clear.\n");
 		log("\n");
 	}
-	virtual void execute(std::vector<std::string> args, RTLIL::Design*)
+	void execute(std::vector<std::string> args, RTLIL::Design*) YS_OVERRIDE
 	{
 		if (args.size() < 2)
 			cmd_error(args, 1, "Missing argument.");
@@ -453,7 +538,7 @@ struct VerilogDefaults : public Pass {
 
 struct VerilogDefines : public Pass {
 	VerilogDefines() : Pass("verilog_defines", "define and undefine verilog defines") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -469,7 +554,7 @@ struct VerilogDefines : public Pass {
 		log("        undefine the preprocessor symbol 'name'\n");
 		log("\n");
 	}
-	virtual void execute(std::vector<std::string> args, RTLIL::Design *design)
+	void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
 	{
 		size_t argidx;
 		for (argidx = 1; argidx < args.size(); argidx++) {
@@ -519,13 +604,11 @@ void frontend_verilog_yyerror(char const *fmt, ...)
 	va_list ap;
 	char buffer[1024];
 	char *p = buffer;
-	p += snprintf(p, buffer + sizeof(buffer) - p, "Parser error in line %s:%d: ",
-			YOSYS_NAMESPACE_PREFIX AST::current_filename.c_str(), frontend_verilog_yyget_lineno());
 	va_start(ap, fmt);
 	p += vsnprintf(p, buffer + sizeof(buffer) - p, fmt, ap);
 	va_end(ap);
 	p += snprintf(p, buffer + sizeof(buffer) - p, "\n");
-	YOSYS_NAMESPACE_PREFIX log_error("%s", buffer);
+	YOSYS_NAMESPACE_PREFIX log_file_error(YOSYS_NAMESPACE_PREFIX AST::current_filename, frontend_verilog_yyget_lineno(),
+					      "%s", buffer);
 	exit(1);
 }
-
diff --git a/frontends/verilog/verilog_frontend.h b/frontends/verilog/verilog_frontend.h
index 16edc7985..a7c9b2fe6 100644
--- a/frontends/verilog/verilog_frontend.h
+++ b/frontends/verilog/verilog_frontend.h
@@ -54,15 +54,27 @@ namespace VERILOG_FRONTEND
 	// running in -formal mode
 	extern bool formal_mode;
 
+	// running in -noassert mode
+	extern bool noassert_mode;
+
+	// running in -noassume mode
+	extern bool noassume_mode;
+
 	// running in -norestrict mode
 	extern bool norestrict_mode;
 
 	// running in -assume-asserts mode
 	extern bool assume_asserts_mode;
 
+	// running in -assert-assumes mode
+	extern bool assert_assumes_mode;
+
 	// running in -lib mode
 	extern bool lib_mode;
 
+	// running in -specify mode
+	extern bool specify_mode;
+
 	// lexer input stream
 	extern std::istream *lexin;
 }
diff --git a/frontends/verilog/verilog_lexer.l b/frontends/verilog/verilog_lexer.l
index d12c9ee4e..4acfb414d 100644
--- a/frontends/verilog/verilog_lexer.l
+++ b/frontends/verilog/verilog_lexer.l
@@ -42,7 +42,7 @@
 #include "kernel/log.h"
 #include "frontends/verilog/verilog_frontend.h"
 #include "frontends/ast/ast.h"
-#include "verilog_parser.tab.h"
+#include "verilog_parser.tab.hh"
 
 USING_YOSYS_NAMESPACE
 using namespace AST;
@@ -70,6 +70,9 @@ YOSYS_NAMESPACE_END
 #define YY_INPUT(buf,result,max_size) \
 	result = readsome(*VERILOG_FRONTEND::lexin, buf, max_size)
 
+#undef YY_BUF_SIZE
+#define YY_BUF_SIZE 65536
+
 %}
 
 %option yylineno
@@ -135,6 +138,9 @@ YOSYS_NAMESPACE_END
 		frontend_verilog_yyerror("Unsupported default nettype: %s", p);
 }
 
+"`protect"[^\n]* /* ignore `protect*/
+"`endprotect"[^\n]* /* ignore `endprotect*/
+
 "`"[a-zA-Z_$][a-zA-Z0-9_$]* {
 	frontend_verilog_yyerror("Unimplemented compiler directive or undefined macro %s.", yytext);
 }
@@ -145,11 +151,14 @@ YOSYS_NAMESPACE_END
 "endfunction"  { return TOK_ENDFUNCTION; }
 "task"         { return TOK_TASK; }
 "endtask"      { return TOK_ENDTASK; }
-"specify"      { return TOK_SPECIFY; }
+"specify"      { return specify_mode ? TOK_SPECIFY : TOK_IGNORED_SPECIFY; }
 "endspecify"   { return TOK_ENDSPECIFY; }
 "specparam"    { return TOK_SPECPARAM; }
 "package"      { SV_KEYWORD(TOK_PACKAGE); }
 "endpackage"   { SV_KEYWORD(TOK_ENDPACKAGE); }
+"interface"    { SV_KEYWORD(TOK_INTERFACE); }
+"endinterface" { SV_KEYWORD(TOK_ENDINTERFACE); }
+"modport"      { SV_KEYWORD(TOK_MODPORT); }
 "parameter"    { return TOK_PARAMETER; }
 "localparam"   { return TOK_LOCALPARAM; }
 "defparam"     { return TOK_DEFPARAM; }
@@ -183,6 +192,16 @@ YOSYS_NAMESPACE_END
 "always_ff"    { SV_KEYWORD(TOK_ALWAYS); }
 "always_latch" { SV_KEYWORD(TOK_ALWAYS); }
 
+ /* use special token for labels on assert, assume, cover, and restrict because it's insanley complex
+    to fix parsing of cells otherwise. (the current cell parser forces a reduce very early to update some
+    global state.. its a mess) */
+[a-zA-Z_$][a-zA-Z0-9_$]*/[ \t\r\n]*:[ \t\r\n]*(assert|assume|cover|restrict)[^a-zA-Z0-9_$\.] {
+	if (!strcmp(yytext, "default"))
+		return TOK_DEFAULT;
+	frontend_verilog_yylval.string = new std::string(std::string("\\") + yytext);
+	return TOK_SVA_LABEL;
+}
+
 "assert"     { if (formal_mode) return TOK_ASSERT; SV_KEYWORD(TOK_ASSERT); }
 "assume"     { if (formal_mode) return TOK_ASSUME; SV_KEYWORD(TOK_ASSUME); }
 "cover"      { if (formal_mode) return TOK_COVER; SV_KEYWORD(TOK_COVER); }
@@ -192,7 +211,9 @@ YOSYS_NAMESPACE_END
 "const"      { if (formal_mode) return TOK_CONST; SV_KEYWORD(TOK_CONST); }
 "checker"    { if (formal_mode) return TOK_CHECKER; SV_KEYWORD(TOK_CHECKER); }
 "endchecker" { if (formal_mode) return TOK_ENDCHECKER; SV_KEYWORD(TOK_ENDCHECKER); }
-"logic"      { SV_KEYWORD(TOK_REG); }
+"final"      { SV_KEYWORD(TOK_FINAL); }
+"logic"      { SV_KEYWORD(TOK_LOGIC); }
+"var"        { SV_KEYWORD(TOK_VAR); }
 "bit"        { SV_KEYWORD(TOK_REG); }
 
 "eventually"   { if (formal_mode) return TOK_EVENTUALLY; SV_KEYWORD(TOK_EVENTUALLY); }
@@ -202,6 +223,8 @@ YOSYS_NAMESPACE_END
 "output"  { return TOK_OUTPUT; }
 "inout"   { return TOK_INOUT; }
 "wire"    { return TOK_WIRE; }
+"wor"     { return TOK_WOR; }
+"wand"    { return TOK_WAND; }
 "reg"     { return TOK_REG; }
 "integer" { return TOK_INTEGER; }
 "signed"  { return TOK_SIGNED; }
@@ -216,7 +239,7 @@ YOSYS_NAMESPACE_END
 	return TOK_CONSTVAL;
 }
 
-[0-9]*[ \t]*\'s?[bodhBODH][ \t\r\n]*[0-9a-fA-FzxZX?_]+ {
+[0-9]*[ \t]*\'[sS]?[bodhBODH]?[ \t\r\n]*[0-9a-fA-FzxZX?_]+ {
 	frontend_verilog_yylval.string = new std::string(yytext);
 	return TOK_CONSTVAL;
 }
@@ -268,7 +291,7 @@ YOSYS_NAMESPACE_END
 		yystr[j++] = yystr[i++];
 	}
 	yystr[j] = 0;
-	frontend_verilog_yylval.string = new std::string(yystr);
+	frontend_verilog_yylval.string = new std::string(yystr, j);
 	free(yystr);
 	return TOK_STRING;
 }
@@ -287,6 +310,17 @@ supply1 { return TOK_SUPPLY1; }
 	return TOK_ID;
 }
 
+"$"(setup|hold|setuphold|removal|recovery|recrem|skew|timeskew|fullskew|nochange) {
+	if (!specify_mode) REJECT;
+	frontend_verilog_yylval.string = new std::string(yytext);
+	return TOK_ID;
+}
+
+"$"(info|warning|error|fatal) {
+	frontend_verilog_yylval.string = new std::string(yytext);
+	return TOK_MSG_TASKS;
+}
+
 "$signed"   { return TOK_TO_SIGNED; }
 "$unsigned" { return TOK_TO_UNSIGNED; }
 
@@ -295,6 +329,11 @@ supply1 { return TOK_SUPPLY1; }
 	return TOK_ID;
 }
 
+[a-zA-Z_$][a-zA-Z0-9_$\.]* {
+	frontend_verilog_yylval.string = new std::string(std::string("\\") + yytext);
+	return TOK_ID;
+}
+
 "/*"[ \t]*(synopsys|synthesis)[ \t]*translate_off[ \t]*"*/" {
 	static bool printed_warning = false;
 	if (!printed_warning) {
@@ -392,6 +431,17 @@ import[ \t\r\n]+\"(DPI|DPI-C)\"[ \t\r\n]+function[ \t\r\n]+ {
 "+:" { return TOK_POS_INDEXED; }
 "-:" { return TOK_NEG_INDEXED; }
 
+[-+]?[=*]> {
+	if (!specify_mode) REJECT;
+	frontend_verilog_yylval.string = new std::string(yytext);
+	return TOK_SPECIFY_OPER;
+}
+
+"&&&" {
+	if (!specify_mode) REJECT;
+	return TOK_SPECIFY_AND;
+}
+
 "/*" { BEGIN(COMMENT); }
 <COMMENT>.    /* ignore comment body */
 <COMMENT>\n   /* ignore comment body */
diff --git a/frontends/verilog/verilog_parser.y b/frontends/verilog/verilog_parser.y
index e803d8072..4afd72b73 100644
--- a/frontends/verilog/verilog_parser.y
+++ b/frontends/verilog/verilog_parser.y
@@ -35,6 +35,7 @@
 
 %{
 #include <list>
+#include <stack>
 #include <string.h>
 #include "frontends/verilog/verilog_frontend.h"
 #include "kernel/log.h"
@@ -47,7 +48,8 @@ YOSYS_NAMESPACE_BEGIN
 namespace VERILOG_FRONTEND {
 	int port_counter;
 	std::map<std::string, int> port_stubs;
-	std::map<std::string, AstNode*> attr_list, default_attr_list;
+	std::map<std::string, AstNode*> *attr_list, default_attr_list;
+	std::stack<std::map<std::string, AstNode*> *> attr_list_stack;
 	std::map<std::string, AstNode*> *albuf;
 	std::vector<AstNode*> ast_stack;
 	struct AstNode *astbuf1, *astbuf2, *astbuf3;
@@ -57,9 +59,11 @@ namespace VERILOG_FRONTEND {
 	std::vector<char> case_type_stack;
 	bool do_not_require_port_stubs;
 	bool default_nettype_wire;
-	bool sv_mode, formal_mode, lib_mode;
-	bool norestrict_mode, assume_asserts_mode;
+	bool sv_mode, formal_mode, lib_mode, specify_mode;
+	bool noassert_mode, noassume_mode, norestrict_mode;
+	bool assume_asserts_mode, assert_assumes_mode;
 	bool current_wire_rand, current_wire_const;
+	bool current_modport_input, current_modport_output;
 	std::istream *lexin;
 }
 YOSYS_NAMESPACE_END
@@ -90,41 +94,77 @@ static void free_attr(std::map<std::string, AstNode*> *al)
 	delete al;
 }
 
+struct specify_target {
+	char polarity_op;
+	AstNode *dst, *dat;
+};
+
+struct specify_triple {
+	AstNode *t_min, *t_avg, *t_max;
+};
+
+struct specify_rise_fall {
+	specify_triple rise;
+	specify_triple fall;
+};
+
 %}
 
-%name-prefix "frontend_verilog_yy"
+%define api.prefix {frontend_verilog_yy}
+
+/* The union is defined in the header, so we need to provide all the
+ * includes it requires
+ */
+%code requires {
+#include <map>
+#include <string>
+#include "frontends/verilog/verilog_frontend.h"
+}
 
 %union {
 	std::string *string;
 	struct YOSYS_NAMESPACE_PREFIX AST::AstNode *ast;
 	std::map<std::string, YOSYS_NAMESPACE_PREFIX AST::AstNode*> *al;
+	struct specify_target *specify_target_ptr;
+	struct specify_triple *specify_triple_ptr;
+	struct specify_rise_fall *specify_rise_fall_ptr;
 	bool boolean;
+	char ch;
 }
 
 %token <string> TOK_STRING TOK_ID TOK_CONSTVAL TOK_REALVAL TOK_PRIMITIVE
+%token <string> TOK_SVA_LABEL TOK_SPECIFY_OPER TOK_MSG_TASKS
+%token TOK_ASSERT TOK_ASSUME TOK_RESTRICT TOK_COVER TOK_FINAL
 %token ATTR_BEGIN ATTR_END DEFATTR_BEGIN DEFATTR_END
 %token TOK_MODULE TOK_ENDMODULE TOK_PARAMETER TOK_LOCALPARAM TOK_DEFPARAM
 %token TOK_PACKAGE TOK_ENDPACKAGE TOK_PACKAGESEP
-%token TOK_INPUT TOK_OUTPUT TOK_INOUT TOK_WIRE TOK_REG
+%token TOK_INTERFACE TOK_ENDINTERFACE TOK_MODPORT TOK_VAR
+%token TOK_INPUT TOK_OUTPUT TOK_INOUT TOK_WIRE TOK_WAND TOK_WOR TOK_REG TOK_LOGIC
 %token TOK_INTEGER TOK_SIGNED TOK_ASSIGN TOK_ALWAYS TOK_INITIAL
 %token TOK_BEGIN TOK_END TOK_IF TOK_ELSE TOK_FOR TOK_WHILE TOK_REPEAT
 %token TOK_DPI_FUNCTION TOK_POSEDGE TOK_NEGEDGE TOK_OR TOK_AUTOMATIC
 %token TOK_CASE TOK_CASEX TOK_CASEZ TOK_ENDCASE TOK_DEFAULT
-%token TOK_FUNCTION TOK_ENDFUNCTION TOK_TASK TOK_ENDTASK TOK_SPECIFY TOK_ENDSPECIFY TOK_SPECPARAM
+%token TOK_FUNCTION TOK_ENDFUNCTION TOK_TASK TOK_ENDTASK TOK_SPECIFY
+%token TOK_IGNORED_SPECIFY TOK_ENDSPECIFY TOK_SPECPARAM TOK_SPECIFY_AND
 %token TOK_GENERATE TOK_ENDGENERATE TOK_GENVAR TOK_REAL
 %token TOK_SYNOPSYS_FULL_CASE TOK_SYNOPSYS_PARALLEL_CASE
 %token TOK_SUPPLY0 TOK_SUPPLY1 TOK_TO_SIGNED TOK_TO_UNSIGNED
-%token TOK_POS_INDEXED TOK_NEG_INDEXED TOK_ASSERT TOK_ASSUME
-%token TOK_RESTRICT TOK_COVER TOK_PROPERTY TOK_ENUM TOK_TYPEDEF
+%token TOK_POS_INDEXED TOK_NEG_INDEXED TOK_PROPERTY TOK_ENUM TOK_TYPEDEF
 %token TOK_RAND TOK_CONST TOK_CHECKER TOK_ENDCHECKER TOK_EVENTUALLY
 %token TOK_INCREMENT TOK_DECREMENT TOK_UNIQUE TOK_PRIORITY
 
 %type <ast> range range_or_multirange  non_opt_range non_opt_multirange range_or_signed_int
 %type <ast> wire_type expr basic_expr concat_list rvalue lvalue lvalue_concat_list
-%type <string> opt_label tok_prim_wrapper hierarchical_id
-%type <boolean> opt_signed unique_case_attr
+%type <string> opt_label opt_sva_label tok_prim_wrapper hierarchical_id
+%type <boolean> opt_signed opt_property unique_case_attr
 %type <al> attr case_attr
 
+%type <specify_target_ptr> specify_target
+%type <specify_triple_ptr> specify_triple
+%type <specify_rise_fall_ptr> specify_rise_fall
+%type <ast> specify_if specify_condition specify_opt_arg
+%type <ch> specify_edge
+
 // operator precedence from low to high
 %left OP_LOR
 %left OP_LAND
@@ -167,19 +207,23 @@ design:
 	param_decl design |
 	localparam_decl design |
 	package design |
+	interface design |
 	/* empty */;
 
 attr:
 	{
-		for (auto &it : attr_list)
-			delete it.second;
-		attr_list.clear();
+		if (attr_list != nullptr)
+			attr_list_stack.push(attr_list);
+		attr_list = new std::map<std::string, AstNode*>;
 		for (auto &it : default_attr_list)
-			attr_list[it.first] = it.second->clone();
+			(*attr_list)[it.first] = it.second->clone();
 	} attr_opt {
-		std::map<std::string, AstNode*> *al = new std::map<std::string, AstNode*>;
-		al->swap(attr_list);
-		$$ = al;
+		$$ = attr_list;
+		if (!attr_list_stack.empty()) {
+			attr_list = attr_list_stack.top();
+			attr_list_stack.pop();
+		} else
+			attr_list = nullptr;
 	};
 
 attr_opt:
@@ -188,15 +232,20 @@ attr_opt:
 
 defattr:
 	DEFATTR_BEGIN {
+		if (attr_list != nullptr)
+			attr_list_stack.push(attr_list);
+		attr_list = new std::map<std::string, AstNode*>;
 		for (auto &it : default_attr_list)
 			delete it.second;
 		default_attr_list.clear();
-		for (auto &it : attr_list)
-			delete it.second;
-		attr_list.clear();
 	} opt_attr_list {
-		default_attr_list = attr_list;
-		attr_list.clear();
+		attr_list->swap(default_attr_list);
+		delete attr_list;
+		if (!attr_list_stack.empty()) {
+			attr_list = attr_list_stack.top();
+			attr_list_stack.pop();
+		} else
+			attr_list = nullptr;
 	} DEFATTR_END;
 
 opt_attr_list:
@@ -208,15 +257,15 @@ attr_list:
 
 attr_assign:
 	hierarchical_id {
-		if (attr_list.count(*$1) != 0)
-			delete attr_list[*$1];
-		attr_list[*$1] = AstNode::mkconst_int(1, false);
+		if (attr_list->count(*$1) != 0)
+			delete (*attr_list)[*$1];
+		(*attr_list)[*$1] = AstNode::mkconst_int(1, false);
 		delete $1;
 	} |
 	hierarchical_id '=' expr {
-		if (attr_list.count(*$1) != 0)
-			delete attr_list[*$1];
-		attr_list[*$1] = $3;
+		if (attr_list->count(*$1) != 0)
+			delete (*attr_list)[*$1];
+		(*attr_list)[*$1] = $3;
 		delete $1;
 	};
 
@@ -225,7 +274,7 @@ hierarchical_id:
 		$$ = $1;
 	} |
 	hierarchical_id TOK_PACKAGESEP TOK_ID {
-		if ($3->substr(0, 1) == "\\")
+		if ($3->compare(0, 1, "\\") == 0)
 			*$1 += "::" + $3->substr(1);
 		else
 			*$1 += "::" + *$3;
@@ -233,7 +282,7 @@ hierarchical_id:
 		$$ = $1;
 	} |
 	hierarchical_id '.' TOK_ID {
-		if ($3->substr(0, 1) == "\\")
+		if ($3->compare(0, 1, "\\") == 0)
 			*$1 += "." + $3->substr(1);
 		else
 			*$1 += "." + *$3;
@@ -270,15 +319,17 @@ module_para_list:
 
 single_module_para:
 	/* empty */ |
-	TOK_PARAMETER {
+	attr TOK_PARAMETER {
 		if (astbuf1) delete astbuf1;
 		astbuf1 = new AstNode(AST_PARAMETER);
 		astbuf1->children.push_back(AstNode::mkconst_int(0, true));
+		append_attr(astbuf1, $1);
 	} param_signed param_integer param_range single_param_decl |
-	TOK_LOCALPARAM {
+	attr TOK_LOCALPARAM {
 		if (astbuf1) delete astbuf1;
 		astbuf1 = new AstNode(AST_LOCALPARAM);
 		astbuf1->children.push_back(AstNode::mkconst_int(0, true));
+		append_attr(astbuf1, $1);
 	} param_signed param_integer param_range single_param_decl |
 	single_param_decl;
 
@@ -296,12 +347,18 @@ module_arg_opt_assignment:
 		if (ast_stack.back()->children.size() > 0 && ast_stack.back()->children.back()->type == AST_WIRE) {
 			AstNode *wire = new AstNode(AST_IDENTIFIER);
 			wire->str = ast_stack.back()->children.back()->str;
-			if (ast_stack.back()->children.back()->is_reg)
+			if (ast_stack.back()->children.back()->is_input) {
+				AstNode *n = ast_stack.back()->children.back();
+				if (n->attributes.count("\\defaultvalue"))
+					delete n->attributes.at("\\defaultvalue");
+				n->attributes["\\defaultvalue"] = $2;
+			} else
+			if (ast_stack.back()->children.back()->is_reg || ast_stack.back()->children.back()->is_logic)
 				ast_stack.back()->children.push_back(new AstNode(AST_INITIAL, new AstNode(AST_BLOCK, new AstNode(AST_ASSIGN_LE, wire, $2))));
 			else
 				ast_stack.back()->children.push_back(new AstNode(AST_ASSIGN, wire, $2));
 		} else
-			frontend_verilog_yyerror("Syntax error.");
+			frontend_verilog_yyerror("SystemVerilog interface in module port list cannot have a default value.");
 	} |
 	/* empty */;
 
@@ -319,6 +376,21 @@ module_arg:
 		}
 		delete $1;
 	} module_arg_opt_assignment |
+	TOK_ID {
+		astbuf1 = new AstNode(AST_INTERFACEPORT);
+		astbuf1->children.push_back(new AstNode(AST_INTERFACEPORTTYPE));
+		astbuf1->children[0]->str = *$1;
+		delete $1;
+	} TOK_ID {  /* SV interfaces */
+		if (!sv_mode)
+			frontend_verilog_yyerror("Interface found in port list (%s). This is not supported unless read_verilog is called with -sv!", $3->c_str());
+		astbuf2 = astbuf1->clone(); // really only needed if multiple instances of same type.
+		astbuf2->str = *$3;
+		delete $3;
+		astbuf2->port_id = ++port_counter;
+		ast_stack.back()->children.push_back(astbuf2);
+		delete astbuf1; // really only needed if multiple instances of same type.
+	} module_arg_opt_assignment |
 	attr wire_type range TOK_ID {
 		AstNode *node = $2;
 		node->str = *$4;
@@ -356,6 +428,33 @@ package_body:
 package_body_stmt:
 	localparam_decl;
 
+interface:
+	TOK_INTERFACE TOK_ID {
+		do_not_require_port_stubs = false;
+		AstNode *intf = new AstNode(AST_INTERFACE);
+		ast_stack.back()->children.push_back(intf);
+		ast_stack.push_back(intf);
+		current_ast_mod = intf;
+		port_stubs.clear();
+		port_counter = 0;
+		intf->str = *$2;
+		delete $2;
+	} module_para_opt module_args_opt ';' interface_body TOK_ENDINTERFACE {
+		if (port_stubs.size() != 0)
+			frontend_verilog_yyerror("Missing details for module port `%s'.",
+				port_stubs.begin()->first.c_str());
+		ast_stack.pop_back();
+		log_assert(ast_stack.size() == 1);
+		current_ast_mod = NULL;
+	};
+
+interface_body:
+	interface_body interface_body_stmt |;
+
+interface_body_stmt:
+	param_decl | localparam_decl | defparam_decl | wire_decl | always_stmt | assign_stmt |
+	modport_stmt;
+
 non_opt_delay:
 	'#' TOK_ID { delete $2; } |
 	'#' TOK_CONSTVAL { delete $2; } |
@@ -376,9 +475,10 @@ wire_type:
 	};
 
 wire_type_token_list:
-	wire_type_token | wire_type_token_list wire_type_token;
+	wire_type_token | wire_type_token_list wire_type_token |
+	wire_type_token_io ;
 
-wire_type_token:
+wire_type_token_io:
 	TOK_INPUT {
 		astbuf3->is_input = true;
 	} |
@@ -388,12 +488,26 @@ wire_type_token:
 	TOK_INOUT {
 		astbuf3->is_input = true;
 		astbuf3->is_output = true;
-	} |
+	};
+
+wire_type_token:
 	TOK_WIRE {
 	} |
+	TOK_WOR {
+		astbuf3->is_wor = true;
+	} |
+	TOK_WAND {
+		astbuf3->is_wand = true;
+	} |
 	TOK_REG {
 		astbuf3->is_reg = true;
 	} |
+	TOK_LOGIC {
+		astbuf3->is_logic = true;
+	} |
+	TOK_VAR {
+		astbuf3->is_logic = true;
+	} |
 	TOK_INTEGER {
 		astbuf3->is_reg = true;
 		astbuf3->range_left = 31;
@@ -403,6 +517,7 @@ wire_type_token:
 	TOK_GENVAR {
 		astbuf3->type = AST_GENVAR;
 		astbuf3->is_reg = true;
+		astbuf3->is_signed = true;
 		astbuf3->range_left = 31;
 		astbuf3->range_right = 0;
 	} |
@@ -477,7 +592,7 @@ module_body:
 
 module_body_stmt:
 	task_func_decl | specify_block |param_decl | localparam_decl | defparam_decl | specparam_declaration | wire_decl | assign_stmt | cell_stmt |
-	always_stmt | TOK_GENERATE module_gen_body TOK_ENDGENERATE | defattr | assert_property | checker_decl;
+	always_stmt | TOK_GENERATE module_gen_body TOK_ENDGENERATE | defattr | assert_property | checker_decl | ignored_specify_block;
 
 checker_decl:
 	TOK_CHECKER TOK_ID ';' {
@@ -545,6 +660,7 @@ task_func_decl:
 		AstNode *outreg = new AstNode(AST_WIRE);
 		outreg->str = *$6;
 		outreg->is_signed = $4;
+		outreg->is_reg = true;
 		if ($5 != NULL) {
 			outreg->children.push_back($5);
 			outreg->is_signed = $4 || $5->is_signed;
@@ -619,7 +735,7 @@ task_func_port:
 		astbuf2 = $3;
 		if (astbuf1->range_left >= 0 && astbuf1->range_right >= 0) {
 			if (astbuf2) {
-				frontend_verilog_yyerror("Syntax error.");
+				frontend_verilog_yyerror("integer/genvar types cannot have packed dimensions (task/function arguments)");
 			} else {
 				astbuf2 = new AstNode(AST_RANGE);
 				astbuf2->children.push_back(AstNode::mkconst_int(astbuf1->range_left, true));
@@ -627,27 +743,266 @@ task_func_port:
 			}
 		}
 		if (astbuf2 && astbuf2->children.size() != 2)
-			frontend_verilog_yyerror("Syntax error.");
+			frontend_verilog_yyerror("task/function argument range must be of the form: [<expr>:<expr>], [<expr>+:<expr>], or [<expr>-:<expr>]");
 	} wire_name | wire_name;
 
 task_func_body:
 	task_func_body behavioral_stmt |
 	/* empty */;
 
+/*************************** specify parser ***************************/
+
 specify_block:
-	TOK_SPECIFY specify_item_opt TOK_ENDSPECIFY |
-	TOK_SPECIFY TOK_ENDSPECIFY ;
+	TOK_SPECIFY specify_item_list TOK_ENDSPECIFY;
 
-specify_item_opt:
-	specify_item_opt specify_item |
-	specify_item ;
+specify_item_list:
+	specify_item specify_item_list |
+	/* empty */;
 
 specify_item:
+	specify_if '(' specify_edge expr TOK_SPECIFY_OPER specify_target ')' '=' specify_rise_fall ';' {
+		AstNode *en_expr = $1;
+		char specify_edge = $3;
+		AstNode *src_expr = $4;
+		string *oper = $5;
+		specify_target *target = $6;
+		specify_rise_fall *timing = $9;
+
+		if (specify_edge != 0 && target->dat == nullptr)
+			frontend_verilog_yyerror("Found specify edge but no data spec.\n");
+
+		AstNode *cell = new AstNode(AST_CELL);
+		ast_stack.back()->children.push_back(cell);
+		cell->str = stringf("$specify$%d", autoidx++);
+		cell->children.push_back(new AstNode(AST_CELLTYPE));
+		cell->children.back()->str = target->dat ? "$specify3" : "$specify2";
+
+		char oper_polarity = 0;
+		char oper_type = oper->at(0);
+
+		if (oper->size() == 3) {
+			oper_polarity = oper->at(0);
+			oper_type = oper->at(1);
+		}
+
+		cell->children.push_back(new AstNode(AST_PARASET, AstNode::mkconst_int(oper_type == '*', false, 1)));
+		cell->children.back()->str = "\\FULL";
+
+		cell->children.push_back(new AstNode(AST_PARASET, AstNode::mkconst_int(oper_polarity != 0, false, 1)));
+		cell->children.back()->str = "\\SRC_DST_PEN";
+
+		cell->children.push_back(new AstNode(AST_PARASET, AstNode::mkconst_int(oper_polarity == '+', false, 1)));
+		cell->children.back()->str = "\\SRC_DST_POL";
+
+		cell->children.push_back(new AstNode(AST_PARASET, timing->rise.t_min));
+		cell->children.back()->str = "\\T_RISE_MIN";
+
+		cell->children.push_back(new AstNode(AST_PARASET, timing->rise.t_avg));
+		cell->children.back()->str = "\\T_RISE_TYP";
+
+		cell->children.push_back(new AstNode(AST_PARASET, timing->rise.t_max));
+		cell->children.back()->str = "\\T_RISE_MAX";
+
+		cell->children.push_back(new AstNode(AST_PARASET, timing->fall.t_min));
+		cell->children.back()->str = "\\T_FALL_MIN";
+
+		cell->children.push_back(new AstNode(AST_PARASET, timing->fall.t_avg));
+		cell->children.back()->str = "\\T_FALL_TYP";
+
+		cell->children.push_back(new AstNode(AST_PARASET, timing->fall.t_max));
+		cell->children.back()->str = "\\T_FALL_MAX";
+
+		cell->children.push_back(new AstNode(AST_ARGUMENT, en_expr ? en_expr : AstNode::mkconst_int(1, false, 1)));
+		cell->children.back()->str = "\\EN";
+
+		cell->children.push_back(new AstNode(AST_ARGUMENT, src_expr));
+		cell->children.back()->str = "\\SRC";
+
+		cell->children.push_back(new AstNode(AST_ARGUMENT, target->dst));
+		cell->children.back()->str = "\\DST";
+
+		if (target->dat)
+		{
+			cell->children.push_back(new AstNode(AST_PARASET, AstNode::mkconst_int(specify_edge != 0, false, 1)));
+			cell->children.back()->str = "\\EDGE_EN";
+
+			cell->children.push_back(new AstNode(AST_PARASET, AstNode::mkconst_int(specify_edge == 'p', false, 1)));
+			cell->children.back()->str = "\\EDGE_POL";
+
+			cell->children.push_back(new AstNode(AST_PARASET, AstNode::mkconst_int(target->polarity_op != 0, false, 1)));
+			cell->children.back()->str = "\\DAT_DST_PEN";
+
+			cell->children.push_back(new AstNode(AST_PARASET, AstNode::mkconst_int(target->polarity_op == '+', false, 1)));
+			cell->children.back()->str = "\\DAT_DST_POL";
+
+			cell->children.push_back(new AstNode(AST_ARGUMENT, target->dat));
+			cell->children.back()->str = "\\DAT";
+		}
+
+		delete oper;
+		delete target;
+		delete timing;
+	} |
+	TOK_ID '(' specify_edge expr specify_condition ',' specify_edge expr specify_condition ',' expr specify_opt_arg ')' ';' {
+		if (*$1 != "$setup" && *$1 != "$hold" && *$1 != "$setuphold" && *$1 != "$removal" && *$1 != "$recovery" &&
+				*$1 != "$recrem" && *$1 != "$skew" && *$1 != "$timeskew" && *$1 != "$fullskew" && *$1 != "$nochange")
+			frontend_verilog_yyerror("Unsupported specify rule type: %s\n", $1->c_str());
+
+		AstNode *src_pen = AstNode::mkconst_int($3 != 0, false, 1);
+		AstNode *src_pol = AstNode::mkconst_int($3 == 'p', false, 1);
+		AstNode *src_expr = $4, *src_en = $5 ? $5 : AstNode::mkconst_int(1, false, 1);
+
+		AstNode *dst_pen = AstNode::mkconst_int($7 != 0, false, 1);
+		AstNode *dst_pol = AstNode::mkconst_int($7 == 'p', false, 1);
+		AstNode *dst_expr = $8, *dst_en = $9 ? $9 : AstNode::mkconst_int(1, false, 1);
+
+		AstNode *limit = $11;
+		AstNode *limit2 = $12;
+
+		AstNode *cell = new AstNode(AST_CELL);
+		ast_stack.back()->children.push_back(cell);
+		cell->str = stringf("$specify$%d", autoidx++);
+		cell->children.push_back(new AstNode(AST_CELLTYPE));
+		cell->children.back()->str = "$specrule";
+
+		cell->children.push_back(new AstNode(AST_PARASET, AstNode::mkconst_str(*$1)));
+		cell->children.back()->str = "\\TYPE";
+
+		cell->children.push_back(new AstNode(AST_PARASET, limit));
+		cell->children.back()->str = "\\T_LIMIT";
+
+		cell->children.push_back(new AstNode(AST_PARASET, limit2 ? limit2 : AstNode::mkconst_int(0, true)));
+		cell->children.back()->str = "\\T_LIMIT2";
+
+		cell->children.push_back(new AstNode(AST_PARASET, src_pen));
+		cell->children.back()->str = "\\SRC_PEN";
+
+		cell->children.push_back(new AstNode(AST_PARASET, src_pol));
+		cell->children.back()->str = "\\SRC_POL";
+
+		cell->children.push_back(new AstNode(AST_PARASET, dst_pen));
+		cell->children.back()->str = "\\DST_PEN";
+
+		cell->children.push_back(new AstNode(AST_PARASET, dst_pol));
+		cell->children.back()->str = "\\DST_POL";
+
+		cell->children.push_back(new AstNode(AST_ARGUMENT, src_en));
+		cell->children.back()->str = "\\SRC_EN";
+
+		cell->children.push_back(new AstNode(AST_ARGUMENT, src_expr));
+		cell->children.back()->str = "\\SRC";
+
+		cell->children.push_back(new AstNode(AST_ARGUMENT, dst_en));
+		cell->children.back()->str = "\\DST_EN";
+
+		cell->children.push_back(new AstNode(AST_ARGUMENT, dst_expr));
+		cell->children.back()->str = "\\DST";
+
+		delete $1;
+	};
+
+specify_opt_arg:
+	',' expr {
+		$$ = $2;
+	} |
+	/* empty */ {
+		$$ = nullptr;
+	};
+
+specify_if:
+	TOK_IF '(' expr ')' {
+		$$ = $3;
+	} |
+	/* empty */ {
+		$$ = nullptr;
+	};
+
+specify_condition:
+	TOK_SPECIFY_AND expr {
+		$$ = $2;
+	} |
+	/* empty */ {
+		$$ = nullptr;
+	};
+
+specify_target:
+	expr {
+		$$ = new specify_target;
+		$$->polarity_op = 0;
+		$$->dst = $1;
+		$$->dat = nullptr;
+	} |
+	'(' expr ':' expr ')'{
+		$$ = new specify_target;
+		$$->polarity_op = 0;
+		$$->dst = $2;
+		$$->dat = $4;
+	} |
+	'(' expr TOK_NEG_INDEXED expr ')'{
+		$$ = new specify_target;
+		$$->polarity_op = '-';
+		$$->dst = $2;
+		$$->dat = $4;
+	} |
+	'(' expr TOK_POS_INDEXED expr ')'{
+		$$ = new specify_target;
+		$$->polarity_op = '+';
+		$$->dst = $2;
+		$$->dat = $4;
+	};
+
+specify_edge:
+	TOK_POSEDGE { $$ = 'p'; } |
+	TOK_NEGEDGE { $$ = 'n'; } |
+	{ $$ = 0; };
+
+specify_rise_fall:
+	specify_triple {
+		$$ = new specify_rise_fall;
+		$$->rise = *$1;
+		$$->fall.t_min = $1->t_min->clone();
+		$$->fall.t_avg = $1->t_avg->clone();
+		$$->fall.t_max = $1->t_max->clone();
+		delete $1;
+	} |
+	'(' specify_triple ',' specify_triple ')' {
+		$$ = new specify_rise_fall;
+		$$->rise = *$2;
+		$$->fall = *$4;
+		delete $2;
+		delete $4;
+	};
+
+specify_triple:
+	expr {
+		$$ = new specify_triple;
+		$$->t_min = $1;
+		$$->t_avg = $1->clone();
+		$$->t_max = $1->clone();
+	} |
+	expr ':' expr ':' expr {
+		$$ = new specify_triple;
+		$$->t_min = $1;
+		$$->t_avg = $3;
+		$$->t_max = $5;
+	};
+
+/******************** ignored specify parser **************************/
+
+ignored_specify_block:
+	TOK_IGNORED_SPECIFY ignored_specify_item_opt TOK_ENDSPECIFY |
+	TOK_IGNORED_SPECIFY TOK_ENDSPECIFY ;
+
+ignored_specify_item_opt:
+	ignored_specify_item_opt ignored_specify_item |
+	ignored_specify_item ;
+
+ignored_specify_item:
 	specparam_declaration
 	// | pulsestyle_declaration
 	// | showcancelled_declaration
 	| path_declaration
-	// | system_timing_declaration
+	| system_timing_declaration
 	;
 
 specparam_declaration:
@@ -658,63 +1013,62 @@ specparam_declaration:
 // and the 'non_opt_range' rule allows index ranges not allowed by 1364-2005
 // exxxxtending this for SV specparam would change this anyhow
 specparam_range:
-	'[' constant_expression ':' constant_expression ']' ;
+	'[' ignspec_constant_expression ':' ignspec_constant_expression ']' ;
 
 list_of_specparam_assignments:
 	specparam_assignment | list_of_specparam_assignments ',' specparam_assignment;
 
 specparam_assignment:
-	TOK_ID '=' constant_mintypmax_expression ;
+	ignspec_id '=' constant_mintypmax_expression ;
 
-/*
-pulsestyle_declaration :
-	;
-
-showcancelled_declaration :
-	;
-*/
+ignspec_opt_cond:
+	TOK_IF '(' ignspec_expr ')' | /* empty */;
 
 path_declaration :
-	simple_path_declaration
+	simple_path_declaration ';'
 	// | edge_sensitive_path_declaration
 	// | state_dependent_path_declaration
 	;
 
 simple_path_declaration :
-	parallel_path_description '=' path_delay_value ';'
-	// | full_path_description '=' path_delay_value ';'
+	ignspec_opt_cond parallel_path_description '=' path_delay_value |
+	ignspec_opt_cond full_path_description '=' path_delay_value
 	;
 
 path_delay_value :
-	//list_of_path_delay_expressions
-	'(' list_of_path_delay_expressions ')'
+	'(' path_delay_expression list_of_path_delay_extra_expressions ')'
+	|     path_delay_expression
+	|     path_delay_expression list_of_path_delay_extra_expressions
 	;
 
-list_of_path_delay_expressions :
-/*
-	t_path_delay_expression
-	| trise_path_delay_expression ',' tfall_path_delay_expression
-	| trise_path_delay_expression ',' tfall_path_delay_expression ',' tz_path_delay_expression
-	| t01_path_delay_expression ',' t10_path_delay_expression ',' t0z_path_delay_expression ','
-	  tz1_path_delay_expression ',' t1z_path_delay_expression ',' tz0_path_delay_expression
-	| t01_path_delay_expression ',' t10_path_delay_expression ',' t0z_path_delay_expression ','
-	  tz1_path_delay_expression ',' t1z_path_delay_expression ',' tz0_path_delay_expression ','
-	  t0x_path_delay_expression ',' tx1_path_delay_expression ',' t1x_path_delay_expression ','
-	  tx0_path_delay_expression ',' txz_path_delay_expression ',' tzx_path_delay_expression
-*/
-	path_delay_expression
-	| path_delay_expression ',' path_delay_expression
-	| path_delay_expression ',' path_delay_expression ',' path_delay_expression
-	| path_delay_expression ',' path_delay_expression ',' path_delay_expression ','
-	  path_delay_expression ',' path_delay_expression ',' path_delay_expression
-	| path_delay_expression ',' path_delay_expression ',' path_delay_expression ','
-	  path_delay_expression ',' path_delay_expression ',' path_delay_expression ','
-	  path_delay_expression ',' path_delay_expression ',' path_delay_expression ','
-	  path_delay_expression ',' path_delay_expression ',' path_delay_expression
-	;
+list_of_path_delay_extra_expressions :
+	',' path_delay_expression | ',' path_delay_expression list_of_path_delay_extra_expressions;
+
+specify_edge_identifier :
+	TOK_POSEDGE | TOK_NEGEDGE ;
 
 parallel_path_description :
-	'(' specify_input_terminal_descriptor opt_polarity_operator '=' '>' specify_output_terminal_descriptor ')' ;
+	'(' specify_input_terminal_descriptor opt_polarity_operator '=' '>' specify_output_terminal_descriptor ')' |
+	'(' specify_edge_identifier specify_input_terminal_descriptor '=' '>' '(' specify_output_terminal_descriptor opt_polarity_operator ':' ignspec_expr ')' ')' |
+	'(' specify_edge_identifier specify_input_terminal_descriptor '=' '>' '(' specify_output_terminal_descriptor TOK_POS_INDEXED ignspec_expr ')' ')' ;
+
+full_path_description :
+	'(' list_of_path_inputs '*' '>' list_of_path_outputs ')' |
+	'(' specify_edge_identifier list_of_path_inputs '*' '>' '(' list_of_path_outputs opt_polarity_operator ':' ignspec_expr ')' ')' |
+	'(' specify_edge_identifier list_of_path_inputs '*' '>' '(' list_of_path_outputs TOK_POS_INDEXED ignspec_expr ')' ')' ;
+
+// This was broken into 2 rules to solve shift/reduce conflicts
+list_of_path_inputs :
+	specify_input_terminal_descriptor                  opt_polarity_operator  |
+	specify_input_terminal_descriptor more_path_inputs opt_polarity_operator ;
+
+more_path_inputs :
+    ',' specify_input_terminal_descriptor |
+    more_path_inputs ',' specify_input_terminal_descriptor ;
+
+list_of_path_outputs :
+	specify_output_terminal_descriptor |
+	list_of_path_outputs ',' specify_output_terminal_descriptor ;
 
 opt_polarity_operator :
 	'+'
@@ -723,81 +1077,46 @@ opt_polarity_operator :
 
 // Good enough for the time being
 specify_input_terminal_descriptor :
-	TOK_ID ;
+	ignspec_id ;
 
 // Good enough for the time being
 specify_output_terminal_descriptor :
-	TOK_ID ;
+	ignspec_id ;
 
-/*
 system_timing_declaration :
-	;
-*/
-
-/*
-t_path_delay_expression :
-	path_delay_expression;
-
-trise_path_delay_expression :
-	path_delay_expression;
+	ignspec_id '(' system_timing_args ')' ';' ;
 
-tfall_path_delay_expression :
-	path_delay_expression;
+system_timing_arg :
+	TOK_POSEDGE ignspec_id |
+	TOK_NEGEDGE ignspec_id |
+	ignspec_expr ;
 
-tz_path_delay_expression :
-	path_delay_expression;
-
-t01_path_delay_expression :
-	path_delay_expression;
-
-t10_path_delay_expression :
-	path_delay_expression;
-
-t0z_path_delay_expression :
-	path_delay_expression;
-
-tz1_path_delay_expression :
-	path_delay_expression;
-
-t1z_path_delay_expression :
-	path_delay_expression;
-
-tz0_path_delay_expression :
-	path_delay_expression;
-
-t0x_path_delay_expression :
-	path_delay_expression;
-
-tx1_path_delay_expression :
-	path_delay_expression;
-
-t1x_path_delay_expression :
-	path_delay_expression;
-
-tx0_path_delay_expression :
-	path_delay_expression;
-
-txz_path_delay_expression :
-	path_delay_expression;
-
-tzx_path_delay_expression :
-	path_delay_expression;
-*/
+system_timing_args :
+	system_timing_arg |
+	system_timing_args ',' system_timing_arg ;
 
 path_delay_expression :
-	constant_mintypmax_expression;
+	ignspec_constant_expression;
 
 constant_mintypmax_expression :
-	constant_expression
-	| constant_expression ':' constant_expression ':' constant_expression
+	ignspec_constant_expression
+	| ignspec_constant_expression ':' ignspec_constant_expression ':' ignspec_constant_expression
 	;
 
 // for the time being this is OK, but we may write our own expr here.
 // as I'm not sure it is legal to use a full expr here (probably not)
 // On the other hand, other rules requiring constant expressions also use 'expr'
-// (such as param assignment), so we may leave this as-is, perhaps assing runtime checks for constant-ness
-constant_expression:
-	expr ;
+// (such as param assignment), so we may leave this as-is, perhaps adding runtime checks for constant-ness
+ignspec_constant_expression:
+	expr { delete $1; };
+
+ignspec_expr:
+	expr { delete $1; };
+
+ignspec_id:
+	TOK_ID { delete $1; };
+
+/**********************************************************************/
 
 param_signed:
 	TOK_SIGNED {
@@ -807,7 +1126,7 @@ param_signed:
 param_integer:
 	TOK_INTEGER {
 		if (astbuf1->children.size() != 1)
-			frontend_verilog_yyerror("Syntax error.");
+			frontend_verilog_yyerror("Internal error in param_integer - should not happen?");
 		astbuf1->children.push_back(new AstNode(AST_RANGE));
 		astbuf1->children.back()->children.push_back(AstNode::mkconst_int(31, true));
 		astbuf1->children.back()->children.push_back(AstNode::mkconst_int(0, true));
@@ -817,7 +1136,7 @@ param_integer:
 param_real:
 	TOK_REAL {
 		if (astbuf1->children.size() != 1)
-			frontend_verilog_yyerror("Syntax error.");
+			frontend_verilog_yyerror("Parameter already declared as integer, cannot set to real.");
 		astbuf1->children.push_back(new AstNode(AST_REALVALUE));
 	} | /* empty */;
 
@@ -825,23 +1144,25 @@ param_range:
 	range {
 		if ($1 != NULL) {
 			if (astbuf1->children.size() != 1)
-				frontend_verilog_yyerror("Syntax error.");
+				frontend_verilog_yyerror("integer/real parameters should not have a range.");
 			astbuf1->children.push_back($1);
 		}
 	};
 
 param_decl:
-	TOK_PARAMETER {
+	attr TOK_PARAMETER {
 		astbuf1 = new AstNode(AST_PARAMETER);
 		astbuf1->children.push_back(AstNode::mkconst_int(0, true));
+		append_attr(astbuf1, $1);
 	} param_signed param_integer param_real param_range param_decl_list ';' {
 		delete astbuf1;
 	};
 
 localparam_decl:
-	TOK_LOCALPARAM {
+	attr TOK_LOCALPARAM {
 		astbuf1 = new AstNode(AST_LOCALPARAM);
 		astbuf1->children.push_back(AstNode::mkconst_int(0, true));
+		append_attr(astbuf1, $1);
 	} param_signed param_integer param_real param_range param_decl_list ';' {
 		delete astbuf1;
 	};
@@ -851,9 +1172,15 @@ param_decl_list:
 
 single_param_decl:
 	TOK_ID '=' expr {
-		if (astbuf1 == nullptr)
-			frontend_verilog_yyerror("syntax error");
-		AstNode *node = astbuf1->clone();
+		AstNode *node;
+		if (astbuf1 == nullptr) {
+			if (!sv_mode)
+				frontend_verilog_yyerror("In pure Verilog (not SystemVerilog), parameter/localparam with an initializer must use the parameter/localparam keyword");
+			node = new AstNode(AST_PARAMETER);
+			node->children.push_back(AstNode::mkconst_int(0, true));
+		} else {
+			node = astbuf1->clone();
+		}
 		node->str = *$1;
 		delete node->children[0];
 		node->children[0] = $3;
@@ -884,7 +1211,7 @@ wire_decl:
 		astbuf2 = $3;
 		if (astbuf1->range_left >= 0 && astbuf1->range_right >= 0) {
 			if (astbuf2) {
-				frontend_verilog_yyerror("Syntax error.");
+				frontend_verilog_yyerror("integer/genvar types cannot have packed dimensions.");
 			} else {
 				astbuf2 = new AstNode(AST_RANGE);
 				astbuf2->children.push_back(AstNode::mkconst_int(astbuf1->range_left, true));
@@ -892,7 +1219,7 @@ wire_decl:
 			}
 		}
 		if (astbuf2 && astbuf2->children.size() != 2)
-			frontend_verilog_yyerror("Syntax error.");
+			frontend_verilog_yyerror("wire/reg/logic packed dimension must be of the form: [<expr>:<expr>], [<expr>+:<expr>], or [<expr>-:<expr>]");
 	} wire_name_list {
 		delete astbuf1;
 		if (astbuf2 != NULL)
@@ -977,7 +1304,12 @@ wire_name_and_opt_assign:
 	wire_name '=' expr {
 		AstNode *wire = new AstNode(AST_IDENTIFIER);
 		wire->str = ast_stack.back()->children.back()->str;
-		if (astbuf1->is_reg)
+		if (astbuf1->is_input) {
+			if (astbuf1->attributes.count("\\defaultvalue"))
+				delete astbuf1->attributes.at("\\defaultvalue");
+			astbuf1->attributes["\\defaultvalue"] = $3;
+		} else
+		if (astbuf1->is_reg || astbuf1->is_logic)
 			ast_stack.back()->children.push_back(new AstNode(AST_INITIAL, new AstNode(AST_BLOCK, new AstNode(AST_ASSIGN_LE, wire, $3))));
 		else
 			ast_stack.back()->children.push_back(new AstNode(AST_ASSIGN, wire, $3));
@@ -986,7 +1318,7 @@ wire_name_and_opt_assign:
 wire_name:
 	TOK_ID range_or_multirange {
 		if (astbuf1 == nullptr)
-			frontend_verilog_yyerror("Syntax error.");
+			frontend_verilog_yyerror("Internal error - should not happen - no AST_WIRE node.");
 		AstNode *node = astbuf1->clone();
 		node->str = *$1;
 		append_attr_clone(node, albuf);
@@ -994,7 +1326,7 @@ wire_name:
 			node->children.push_back(astbuf2->clone());
 		if ($2 != NULL) {
 			if (node->is_input || node->is_output)
-				frontend_verilog_yyerror("Syntax error.");
+				frontend_verilog_yyerror("input/output/inout ports cannot have unpacked dimensions.");
 			if (!astbuf2) {
 				AstNode *rng = new AstNode(AST_RANGE);
 				rng->children.push_back(AstNode::mkconst_int(0, true));
@@ -1002,7 +1334,13 @@ wire_name:
 				node->children.push_back(rng);
 			}
 			node->type = AST_MEMORY;
-			node->children.push_back($2);
+			auto *rangeNode = $2;
+			if (rangeNode->type == AST_RANGE && rangeNode->children.size() == 1) {
+				// SV array size [n], rewrite as [n-1:0]
+				rangeNode->children[0] = new AstNode(AST_SUB, rangeNode->children[0], AstNode::mkconst_int(1, true));
+				rangeNode->children.push_back(AstNode::mkconst_int(0, false));
+			}
+			node->children.push_back(rangeNode);
 		}
 		if (current_function_or_task == NULL) {
 			if (do_not_require_port_stubs && (node->is_input || node->is_output) && port_stubs.count(*$1) == 0) {
@@ -1024,6 +1362,7 @@ wire_name:
 				node->port_id = current_function_or_task_port_id++;
 		}
 		ast_stack.back()->children.push_back(node);
+
 		delete $1;
 	};
 
@@ -1148,27 +1487,40 @@ cell_port_list_rules:
 	cell_port | cell_port_list_rules ',' cell_port;
 
 cell_port:
-	/* empty */ {
+	attr {
 		AstNode *node = new AstNode(AST_ARGUMENT);
 		astbuf2->children.push_back(node);
+		free_attr($1);
 	} |
-	expr {
+	attr expr {
 		AstNode *node = new AstNode(AST_ARGUMENT);
 		astbuf2->children.push_back(node);
-		node->children.push_back($1);
+		node->children.push_back($2);
+		free_attr($1);
 	} |
-	'.' TOK_ID '(' expr ')' {
+	attr '.' TOK_ID '(' expr ')' {
 		AstNode *node = new AstNode(AST_ARGUMENT);
-		node->str = *$2;
+		node->str = *$3;
 		astbuf2->children.push_back(node);
-		node->children.push_back($4);
-		delete $2;
+		node->children.push_back($5);
+		delete $3;
+		free_attr($1);
 	} |
-	'.' TOK_ID '(' ')' {
+	attr '.' TOK_ID '(' ')' {
 		AstNode *node = new AstNode(AST_ARGUMENT);
-		node->str = *$2;
+		node->str = *$3;
 		astbuf2->children.push_back(node);
-		delete $2;
+		delete $3;
+		free_attr($1);
+	} |
+	attr '.' TOK_ID {
+		AstNode *node = new AstNode(AST_ARGUMENT);
+		node->str = *$3;
+		astbuf2->children.push_back(node);
+		node->children.push_back(new AstNode(AST_IDENTIFIER));
+		node->children.back()->str = *$3;
+		delete $3;
+		free_attr($1);
 	};
 
 always_stmt:
@@ -1236,74 +1588,219 @@ opt_label:
 		$$ = NULL;
 	};
 
+opt_sva_label:
+	TOK_SVA_LABEL ':' {
+		$$ = $1;
+	} |
+	/* empty */ {
+		$$ = NULL;
+	};
+
 opt_property:
-	TOK_PROPERTY | /* empty */;
+	TOK_PROPERTY {
+		$$ = true;
+	} |
+	TOK_FINAL {
+		$$ = false;
+	} |
+	/* empty */ {
+		$$ = false;
+	};
 
-opt_stmt_label:
-	TOK_ID ':' | /* empty */;
+modport_stmt:
+    TOK_MODPORT TOK_ID {
+        AstNode *modport = new AstNode(AST_MODPORT);
+        ast_stack.back()->children.push_back(modport);
+        ast_stack.push_back(modport);
+        modport->str = *$2;
+        delete $2;
+    }  modport_args_opt {
+        ast_stack.pop_back();
+        log_assert(ast_stack.size() == 2);
+    } ';'
+
+modport_args_opt:
+    '(' ')' | '(' modport_args optional_comma ')';
+
+modport_args:
+    modport_arg | modport_args ',' modport_arg;
+
+modport_arg:
+    modport_type_token modport_member |
+    modport_member
+
+modport_member:
+    TOK_ID {
+        AstNode *modport_member = new AstNode(AST_MODPORTMEMBER);
+        ast_stack.back()->children.push_back(modport_member);
+        modport_member->str = *$1;
+        modport_member->is_input = current_modport_input;
+        modport_member->is_output = current_modport_output;
+        delete $1;
+    }
+
+modport_type_token:
+    TOK_INPUT {current_modport_input = 1; current_modport_output = 0;} | TOK_OUTPUT {current_modport_input = 0; current_modport_output = 1;}
 
 assert:
-	opt_stmt_label TOK_ASSERT opt_property '(' expr ')' ';' {
-		ast_stack.back()->children.push_back(new AstNode(assume_asserts_mode ? AST_ASSUME : AST_ASSERT, $5));
+	opt_sva_label TOK_ASSERT opt_property '(' expr ')' ';' {
+		if (noassert_mode) {
+			delete $5;
+		} else {
+			AstNode *node = new AstNode(assume_asserts_mode ? AST_ASSUME : AST_ASSERT, $5);
+			if ($1 != nullptr)
+				node->str = *$1;
+			ast_stack.back()->children.push_back(node);
+		}
+		if ($1 != nullptr)
+			delete $1;
 	} |
-	opt_stmt_label TOK_ASSUME opt_property '(' expr ')' ';' {
-		ast_stack.back()->children.push_back(new AstNode(AST_ASSUME, $5));
+	opt_sva_label TOK_ASSUME opt_property '(' expr ')' ';' {
+		if (noassume_mode) {
+			delete $5;
+		} else {
+			AstNode *node = new AstNode(assert_assumes_mode ? AST_ASSERT : AST_ASSUME, $5);
+			if ($1 != nullptr)
+				node->str = *$1;
+			ast_stack.back()->children.push_back(node);
+		}
+		if ($1 != nullptr)
+			delete $1;
 	} |
-	opt_stmt_label TOK_ASSERT opt_property '(' TOK_EVENTUALLY expr ')' ';' {
-		ast_stack.back()->children.push_back(new AstNode(assume_asserts_mode ? AST_FAIR : AST_LIVE, $6));
+	opt_sva_label TOK_ASSERT opt_property '(' TOK_EVENTUALLY expr ')' ';' {
+		if (noassert_mode) {
+			delete $6;
+		} else {
+			AstNode *node = new AstNode(assume_asserts_mode ? AST_FAIR : AST_LIVE, $6);
+			if ($1 != nullptr)
+				node->str = *$1;
+			ast_stack.back()->children.push_back(node);
+		}
+		if ($1 != nullptr)
+			delete $1;
 	} |
-	opt_stmt_label TOK_ASSUME opt_property '(' TOK_EVENTUALLY expr ')' ';' {
-		ast_stack.back()->children.push_back(new AstNode(AST_FAIR, $6));
+	opt_sva_label TOK_ASSUME opt_property '(' TOK_EVENTUALLY expr ')' ';' {
+		if (noassume_mode) {
+			delete $6;
+		} else {
+			AstNode *node = new AstNode(assert_assumes_mode ? AST_LIVE : AST_FAIR, $6);
+			if ($1 != nullptr)
+				node->str = *$1;
+			ast_stack.back()->children.push_back(node);
+		}
+		if ($1 != nullptr)
+			delete $1;
 	} |
-	opt_stmt_label TOK_COVER opt_property '(' expr ')' ';' {
-		ast_stack.back()->children.push_back(new AstNode(AST_COVER, $5));
+	opt_sva_label TOK_COVER opt_property '(' expr ')' ';' {
+		AstNode *node = new AstNode(AST_COVER, $5);
+		if ($1 != nullptr) {
+			node->str = *$1;
+			delete $1;
+		}
+		ast_stack.back()->children.push_back(node);
 	} |
-	opt_stmt_label TOK_COVER opt_property '(' ')' ';' {
-		ast_stack.back()->children.push_back(new AstNode(AST_COVER, AstNode::mkconst_int(1, false)));
+	opt_sva_label TOK_COVER opt_property '(' ')' ';' {
+		AstNode *node = new AstNode(AST_COVER, AstNode::mkconst_int(1, false));
+		if ($1 != nullptr) {
+			node->str = *$1;
+			delete $1;
+		}
+		ast_stack.back()->children.push_back(node);
 	} |
-	opt_stmt_label TOK_COVER ';' {
-		ast_stack.back()->children.push_back(new AstNode(AST_COVER, AstNode::mkconst_int(1, false)));
+	opt_sva_label TOK_COVER ';' {
+		AstNode *node = new AstNode(AST_COVER, AstNode::mkconst_int(1, false));
+		if ($1 != nullptr) {
+			node->str = *$1;
+			delete $1;
+		}
+		ast_stack.back()->children.push_back(node);
 	} |
-	opt_stmt_label TOK_RESTRICT opt_property '(' expr ')' ';' {
-		if (norestrict_mode)
+	opt_sva_label TOK_RESTRICT opt_property '(' expr ')' ';' {
+		if (norestrict_mode) {
 			delete $5;
-		else
-			ast_stack.back()->children.push_back(new AstNode(AST_ASSUME, $5));
+		} else {
+			AstNode *node = new AstNode(AST_ASSUME, $5);
+			if ($1 != nullptr)
+				node->str = *$1;
+			ast_stack.back()->children.push_back(node);
+		}
+		if (!$3)
+			log_file_warning(current_filename, get_line_num(), "SystemVerilog does not allow \"restrict\" without \"property\".\n");
+		if ($1 != nullptr)
+			delete $1;
 	} |
-	opt_stmt_label TOK_RESTRICT opt_property '(' TOK_EVENTUALLY expr ')' ';' {
-		if (norestrict_mode)
+	opt_sva_label TOK_RESTRICT opt_property '(' TOK_EVENTUALLY expr ')' ';' {
+		if (norestrict_mode) {
 			delete $6;
-		else
-			ast_stack.back()->children.push_back(new AstNode(AST_FAIR, $6));
+		} else {
+			AstNode *node = new AstNode(AST_FAIR, $6);
+			if ($1 != nullptr)
+				node->str = *$1;
+			ast_stack.back()->children.push_back(node);
+		}
+		if (!$3)
+			log_file_warning(current_filename, get_line_num(), "SystemVerilog does not allow \"restrict\" without \"property\".\n");
+		if ($1 != nullptr)
+			delete $1;
 	};
 
 assert_property:
-	TOK_ASSERT TOK_PROPERTY '(' expr ')' ';' {
-		ast_stack.back()->children.push_back(new AstNode(assume_asserts_mode ? AST_ASSUME : AST_ASSERT, $4));
-	} |
-	TOK_ASSUME TOK_PROPERTY '(' expr ')' ';' {
-		ast_stack.back()->children.push_back(new AstNode(AST_ASSUME, $4));
+	opt_sva_label TOK_ASSERT TOK_PROPERTY '(' expr ')' ';' {
+		ast_stack.back()->children.push_back(new AstNode(assume_asserts_mode ? AST_ASSUME : AST_ASSERT, $5));
+		if ($1 != nullptr) {
+			ast_stack.back()->children.back()->str = *$1;
+			delete $1;
+		}
 	} |
-	TOK_ASSERT TOK_PROPERTY '(' TOK_EVENTUALLY expr ')' ';' {
-		ast_stack.back()->children.push_back(new AstNode(assume_asserts_mode ? AST_FAIR : AST_LIVE, $5));
+	opt_sva_label TOK_ASSUME TOK_PROPERTY '(' expr ')' ';' {
+		ast_stack.back()->children.push_back(new AstNode(AST_ASSUME, $5));
+		if ($1 != nullptr) {
+			ast_stack.back()->children.back()->str = *$1;
+			delete $1;
+		}
 	} |
-	TOK_ASSUME TOK_PROPERTY '(' TOK_EVENTUALLY expr ')' ';' {
-		ast_stack.back()->children.push_back(new AstNode(AST_FAIR, $5));
+	opt_sva_label TOK_ASSERT TOK_PROPERTY '(' TOK_EVENTUALLY expr ')' ';' {
+		ast_stack.back()->children.push_back(new AstNode(assume_asserts_mode ? AST_FAIR : AST_LIVE, $6));
+		if ($1 != nullptr) {
+			ast_stack.back()->children.back()->str = *$1;
+			delete $1;
+		}
 	} |
-	TOK_COVER TOK_PROPERTY '(' expr ')' ';' {
-		ast_stack.back()->children.push_back(new AstNode(AST_COVER, $4));
+	opt_sva_label TOK_ASSUME TOK_PROPERTY '(' TOK_EVENTUALLY expr ')' ';' {
+		ast_stack.back()->children.push_back(new AstNode(AST_FAIR, $6));
+		if ($1 != nullptr) {
+			ast_stack.back()->children.back()->str = *$1;
+			delete $1;
+		}
 	} |
-	TOK_RESTRICT TOK_PROPERTY '(' expr ')' ';' {
-		if (norestrict_mode)
-			delete $4;
-		else
-			ast_stack.back()->children.push_back(new AstNode(AST_ASSUME, $4));
+	opt_sva_label TOK_COVER TOK_PROPERTY '(' expr ')' ';' {
+		ast_stack.back()->children.push_back(new AstNode(AST_COVER, $5));
+		if ($1 != nullptr) {
+			ast_stack.back()->children.back()->str = *$1;
+			delete $1;
+		}
 	} |
-	TOK_RESTRICT TOK_PROPERTY '(' TOK_EVENTUALLY expr ')' ';' {
-		if (norestrict_mode)
+	opt_sva_label TOK_RESTRICT TOK_PROPERTY '(' expr ')' ';' {
+		if (norestrict_mode) {
 			delete $5;
-		else
-			ast_stack.back()->children.push_back(new AstNode(AST_FAIR, $5));
+		} else {
+			ast_stack.back()->children.push_back(new AstNode(AST_ASSUME, $5));
+			if ($1 != nullptr) {
+				ast_stack.back()->children.back()->str = *$1;
+				delete $1;
+			}
+		}
+	} |
+	opt_sva_label TOK_RESTRICT TOK_PROPERTY '(' TOK_EVENTUALLY expr ')' ';' {
+		if (norestrict_mode) {
+			delete $6;
+		} else {
+			ast_stack.back()->children.push_back(new AstNode(AST_FAIR, $6));
+			if ($1 != nullptr) {
+				ast_stack.back()->children.back()->str = *$1;
+				delete $1;
+			}
+		}
 	};
 
 simple_behavioral_stmt:
@@ -1339,6 +1836,16 @@ behavioral_stmt:
 	} opt_arg_list ';'{
 		ast_stack.pop_back();
 	} |
+	TOK_MSG_TASKS attr {
+		AstNode *node = new AstNode(AST_TCALL);
+		node->str = *$1;
+		delete $1;
+		ast_stack.back()->children.push_back(node);
+		ast_stack.push_back(node);
+		append_attr(node, $2);
+	} opt_arg_list ';'{
+		ast_stack.pop_back();
+	} |
 	attr TOK_BEGIN opt_label {
 		AstNode *node = new AstNode(AST_BLOCK);
 		ast_stack.back()->children.push_back(node);
@@ -1348,7 +1855,7 @@ behavioral_stmt:
 			node->str = *$3;
 	} behavioral_stmt_list TOK_END opt_label {
 		if ($3 != NULL && $7 != NULL && *$3 != *$7)
-			frontend_verilog_yyerror("Syntax error.");
+			frontend_verilog_yyerror("Begin label (%s) and end label (%s) don't match.", $3->c_str()+1, $7->c_str()+1);
 		if ($3 != NULL)
 			delete $3;
 		if ($7 != NULL)
@@ -1521,6 +2028,11 @@ case_expr_list:
 	TOK_DEFAULT {
 		ast_stack.back()->children.push_back(new AstNode(AST_DEFAULT));
 	} |
+	TOK_SVA_LABEL {
+		ast_stack.back()->children.push_back(new AstNode(AST_IDENTIFIER));
+		ast_stack.back()->children.back()->str = *$1;
+		delete $1;
+	} |
 	expr {
 		ast_stack.back()->children.push_back($1);
 	} |
@@ -1629,6 +2141,15 @@ gen_stmt:
 		if ($6 != NULL)
 			delete $6;
 		ast_stack.pop_back();
+	} |
+	TOK_MSG_TASKS {
+		AstNode *node = new AstNode(AST_TECALL);
+		node->str = *$1;
+		delete $1;
+		ast_stack.back()->children.push_back(node);
+		ast_stack.push_back(node);
+	} opt_arg_list ';'{
+		ast_stack.pop_back();		
 	};
 
 gen_stmt_block:
@@ -1663,8 +2184,8 @@ basic_expr:
 		$$ = $1;
 	} |
 	'(' expr ')' TOK_CONSTVAL {
-		if ($4->substr(0, 1) != "'")
-			frontend_verilog_yyerror("Syntax error.");
+		if ($4->compare(0, 1, "'") != 0)
+			frontend_verilog_yyerror("Cast operation must be applied on sized constants e.g. (<expr>)<constval> , while %s is not a sized constant.", $4->c_str());
 		AstNode *bits = $2;
 		AstNode *val = const2ast(*$4, case_type_stack.size() == 0 ? 0 : case_type_stack.back(), !lib_mode);
 		if (val == NULL)
@@ -1673,8 +2194,8 @@ basic_expr:
 		delete $4;
 	} |
 	hierarchical_id TOK_CONSTVAL {
-		if ($2->substr(0, 1) != "'")
-			frontend_verilog_yyerror("Syntax error.");
+		if ($2->compare(0, 1, "'") != 0)
+			frontend_verilog_yyerror("Cast operation must be applied on sized constants, e.g. <ID>\'d0, while %s is not a sized constant.", $2->c_str());
 		AstNode *bits = new AstNode(AST_IDENTIFIER);
 		bits->str = *$1;
 		AstNode *val = const2ast(*$2, case_type_stack.size() == 0 ? 0 : case_type_stack.back(), !lib_mode);
@@ -1899,4 +2420,3 @@ concat_list:
 		$$ = $3;
 		$$->children.push_back($1);
 	};
-