Merge pull request #3 from YosysHQ/master

Updates from official repo

187 files changed, 1097 insertions, 728 deletions

diff --git a/CodingReadme b/CodingReadme
index 5800e30c3..4ab132a63 100644
--- a/CodingReadme
+++ b/CodingReadme
@@ -21,7 +21,7 @@ Here is a the C++ code for a "hello_world" Yosys command (hello.cc):
 
 	struct HelloWorldPass : public Pass {
 		HelloWorldPass() : Pass("hello_world") { }
-		virtual void execute(vector<string>, Design*) {
+		void execute(vector<string>, Design*) override {
 			log("Hello World!\n");
 		}
 	} HelloWorldPass;
diff --git a/Makefile b/Makefile
index 11803ec0a..eed4e8f23 100644
--- a/Makefile
+++ b/Makefile
@@ -5,6 +5,7 @@ CONFIG := clang
 # CONFIG := emcc
 # CONFIG := mxe
 # CONFIG := msys2
+# CONFIG := msys2-64
 
 # features (the more the better)
 ENABLE_TCL := 1
@@ -107,7 +108,7 @@ OBJS = kernel/version_$(GIT_REV).o
 # is just a symlink to your actual ABC working directory, as 'make mrproper'
 # will remove the 'abc' directory and you do not want to accidentally
 # delete your work on ABC..
-ABCREV = 6df1396
+ABCREV = ae6716b
 ABCPULL = 1
 ABCURL ?= https://github.com/berkeley-abc/abc
 ABCMKARGS = CC="$(CXX)" CXX="$(CXX)" ABC_USE_LIBSTDCXX=1
@@ -199,14 +200,14 @@ yosys.html: misc/yosys.html
 
 else ifeq ($(CONFIG),mxe)
 PKG_CONFIG = /usr/local/src/mxe/usr/bin/i686-w64-mingw32.static-pkg-config
-CXX = /usr/local/src/mxe/usr/bin/i686-w64-mingw32.static-gcc
-LD = /usr/local/src/mxe/usr/bin/i686-w64-mingw32.static-gcc
+CXX = /usr/local/src/mxe/usr/bin/i686-w64-mingw32.static-g++
+LD = /usr/local/src/mxe/usr/bin/i686-w64-mingw32.static-g++
 CXXFLAGS += -std=c++11 -Os -D_POSIX_SOURCE -DYOSYS_MXE_HACKS -Wno-attributes
 CXXFLAGS := $(filter-out -fPIC,$(CXXFLAGS))
 LDFLAGS := $(filter-out -rdynamic,$(LDFLAGS)) -s
 LDLIBS := $(filter-out -lrt,$(LDLIBS))
-ABCMKARGS += ARCHFLAGS="-DABC_USE_STDINT_H -DWIN32_NO_DLL -DHAVE_STRUCT_TIMESPEC -fpermissive -w"
-ABCMKARGS += LIBS="lib/x86/pthreadVC2.lib -s" ABC_USE_NO_READLINE=1
+ABCMKARGS += ARCHFLAGS="-DWIN32_NO_DLL -DHAVE_STRUCT_TIMESPEC -fpermissive -w"
+ABCMKARGS += LIBS="lib/x86/pthreadVC2.lib -s" ABC_USE_NO_READLINE=1 CC="/usr/local/src/mxe/usr/bin/i686-w64-mingw32.static-gcc"
 EXE = .exe
 
 else ifeq ($(CONFIG),msys2)
@@ -217,11 +218,22 @@ CXXFLAGS := $(filter-out -fPIC,$(CXXFLAGS))
 LDFLAGS := $(filter-out -rdynamic,$(LDFLAGS)) -s
 LDLIBS := $(filter-out -lrt,$(LDLIBS))
 ABCMKARGS += ARCHFLAGS="-DABC_USE_STDINT_H -DWIN32_NO_DLL -DHAVE_STRUCT_TIMESPEC -fpermissive -w"
-ABCMKARGS += LIBS="lib/x86/pthreadVC2.lib -s" ABC_USE_NO_READLINE=0
+ABCMKARGS += LIBS="-lpthread -s" ABC_USE_NO_READLINE=0 CC="i686-w64-mingw32-gcc" CXX="$(CXX)"
+EXE = .exe
+
+else ifeq ($(CONFIG),msys2-64)
+CXX = x86_64-w64-mingw32-g++
+LD = x86_64-w64-mingw32-g++
+CXXFLAGS += -std=c++11 -Os -D_POSIX_SOURCE -DYOSYS_WIN32_UNIX_DIR
+CXXFLAGS := $(filter-out -fPIC,$(CXXFLAGS))
+LDFLAGS := $(filter-out -rdynamic,$(LDFLAGS)) -s
+LDLIBS := $(filter-out -lrt,$(LDLIBS))
+ABCMKARGS += ARCHFLAGS="-DABC_USE_STDINT_H -DWIN32_NO_DLL -DHAVE_STRUCT_TIMESPEC -fpermissive -w"
+ABCMKARGS += LIBS="-lpthread -s" ABC_USE_NO_READLINE=0 CC="x86_64-w64-mingw32-gcc" CXX="$(CXX)"
 EXE = .exe
 
 else ifneq ($(CONFIG),none)
-$(error Invalid CONFIG setting '$(CONFIG)'. Valid values: clang, gcc, gcc-4.8, emcc, mxe, msys2)
+$(error Invalid CONFIG setting '$(CONFIG)'. Valid values: clang, gcc, gcc-4.8, emcc, mxe, msys2, msys2-64)
 endif
 
 ifeq ($(ENABLE_LIBYOSYS),1)
@@ -276,7 +288,7 @@ endif
 
 ifeq ($(CONFIG),mxe)
 CXXFLAGS += -DYOSYS_ENABLE_TCL
-LDLIBS += -ltcl86 -lwsock32 -lws2_32 -lnetapi32
+LDLIBS += -ltcl86 -lwsock32 -lws2_32 -lnetapi32 -lz
 else
 CXXFLAGS += $(shell PKG_CONFIG_PATH=$(PKG_CONFIG_PATH) $(PKG_CONFIG) --silence-errors --cflags tcl || echo -I$(TCL_INCLUDE)) -DYOSYS_ENABLE_TCL
 ifeq ($(OS), FreeBSD)
@@ -676,6 +688,9 @@ config-mxe: clean
 config-msys2: clean
 	echo 'CONFIG := msys2' > Makefile.conf
 
+config-msys2-64: clean
+	echo 'CONFIG := msys2-64' > Makefile.conf
+
 config-gprof: clean
 	echo 'CONFIG := gcc' > Makefile.conf
 	echo 'ENABLE_GPROF := 1' >> Makefile.conf
diff --git a/README.md b/README.md
index c02691d94..424d9bbf2 100644
--- a/README.md
+++ b/README.md
@@ -389,7 +389,7 @@ Verilog Attributes and non-standard features
 Non-standard or SystemVerilog features for formal verification
 ==============================================================
 
-- Support for ``assert``, ``assume``, ``restrict``, and ``cover'' is enabled
+- Support for ``assert``, ``assume``, ``restrict``, and ``cover`` is enabled
   when ``read_verilog`` is called with ``-formal``.
 
 - The system task ``$initstate`` evaluates to 1 in the initial state and
diff --git a/backends/aiger/aiger.cc b/backends/aiger/aiger.cc
index 526e50a49..c323691a3 100644
--- a/backends/aiger/aiger.cc
+++ b/backends/aiger/aiger.cc
@@ -657,7 +657,7 @@ struct AigerWriter
 
 struct AigerBackend : public Backend {
 	AigerBackend() : Backend("aiger", "write design to AIGER file") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -690,7 +690,7 @@ struct AigerBackend : public Backend {
 		log("        like -map, but more verbose\n");
 		log("\n");
 	}
-	virtual void execute(std::ostream *&f, std::string filename, std::vector<std::string> args, RTLIL::Design *design)
+	void execute(std::ostream *&f, std::string filename, std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
 	{
 		bool ascii_mode = false;
 		bool zinit_mode = false;
diff --git a/backends/blif/blif.cc b/backends/blif/blif.cc
index e4509e0d0..0db5ff27c 100644
--- a/backends/blif/blif.cc
+++ b/backends/blif/blif.cc
@@ -464,7 +464,7 @@ struct BlifDumper
 
 struct BlifBackend : public Backend {
 	BlifBackend() : Backend("blif", "write design to BLIF file") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -534,7 +534,7 @@ struct BlifBackend : public Backend {
 		log("        do not write definitions for the $true, $false and $undef wires.\n");
 		log("\n");
 	}
-	virtual void execute(std::ostream *&f, std::string filename, std::vector<std::string> args, RTLIL::Design *design)
+	void execute(std::ostream *&f, std::string filename, std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
 	{
 		std::string top_module_name;
 		std::string buf_type, buf_in, buf_out;
diff --git a/backends/btor/btor.cc b/backends/btor/btor.cc
index 61a2f8ba3..58d2a8625 100644
--- a/backends/btor/btor.cc
+++ b/backends/btor/btor.cc
@@ -1076,7 +1076,7 @@ struct BtorWorker
 
 struct BtorBackend : public Backend {
 	BtorBackend() : Backend("btor", "write design to BTOR file") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -1091,7 +1091,7 @@ struct BtorBackend : public Backend {
 		log("    Output only a single bad property for all asserts\n");
 		log("\n");
 	}
-	virtual void execute(std::ostream *&f, std::string filename, std::vector<std::string> args, RTLIL::Design *design)
+	void execute(std::ostream *&f, std::string filename, std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
 	{
 		bool verbose = false, single_bad = false;
 
diff --git a/backends/edif/edif.cc b/backends/edif/edif.cc
index a6534b911..5f9ec54fd 100644
--- a/backends/edif/edif.cc
+++ b/backends/edif/edif.cc
@@ -90,7 +90,7 @@ struct EdifNames
 
 struct EdifBackend : public Backend {
 	EdifBackend() : Backend("edif", "write design to EDIF netlist file") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -116,7 +116,7 @@ struct EdifBackend : public Backend {
 		log("is targeted.\n");
 		log("\n");
 	}
-	virtual void execute(std::ostream *&f, std::string filename, std::vector<std::string> args, RTLIL::Design *design)
+	void execute(std::ostream *&f, std::string filename, std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
 	{
 		log_header(design, "Executing EDIF backend.\n");
 		std::string top_module_name;
diff --git a/backends/firrtl/firrtl.cc b/backends/firrtl/firrtl.cc
index 06cbc9b2b..4f56f498c 100644
--- a/backends/firrtl/firrtl.cc
+++ b/backends/firrtl/firrtl.cc
@@ -527,7 +527,7 @@ struct FirrtlWorker
 
 struct FirrtlBackend : public Backend {
 	FirrtlBackend() : Backend("firrtl", "write design to a FIRRTL file") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -536,7 +536,7 @@ struct FirrtlBackend : public Backend {
 		log("Write a FIRRTL netlist of the current design.\n");
 		log("\n");
 	}
-	virtual void execute(std::ostream *&f, std::string filename, std::vector<std::string> args, RTLIL::Design *design)
+	void execute(std::ostream *&f, std::string filename, std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
 	{
 		size_t argidx;
 		for (argidx = 1; argidx < args.size(); argidx++)
diff --git a/backends/ilang/ilang_backend.cc b/backends/ilang/ilang_backend.cc
index 1f7f12361..4c58ea087 100644
--- a/backends/ilang/ilang_backend.cc
+++ b/backends/ilang/ilang_backend.cc
@@ -382,7 +382,7 @@ PRIVATE_NAMESPACE_BEGIN
 
 struct IlangBackend : public Backend {
 	IlangBackend() : Backend("ilang", "write design to ilang file") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -395,7 +395,7 @@ struct IlangBackend : public Backend {
 		log("        only write selected parts of the design.\n");
 		log("\n");
 	}
-	virtual void execute(std::ostream *&f, std::string filename, std::vector<std::string> args, RTLIL::Design *design)
+	void execute(std::ostream *&f, std::string filename, std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
 	{
 		bool selected = false;
 
@@ -422,7 +422,7 @@ struct IlangBackend : public Backend {
 
 struct DumpPass : public Pass {
 	DumpPass() : Pass("dump", "print parts of the design in ilang format") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -445,7 +445,7 @@ struct DumpPass : public Pass {
 		log("        like -outfile but append instead of overwrite\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
 	{
 		std::string filename;
 		bool flag_m = false, flag_n = false, append = false;
diff --git a/backends/intersynth/intersynth.cc b/backends/intersynth/intersynth.cc
index 34cb52fb4..2eb08dbe9 100644
--- a/backends/intersynth/intersynth.cc
+++ b/backends/intersynth/intersynth.cc
@@ -46,7 +46,7 @@ static std::string netname(std::set<std::string> &conntypes_code, std::set<std::
 
 struct IntersynthBackend : public Backend {
 	IntersynthBackend() : Backend("intersynth", "write design to InterSynth netlist file") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -71,7 +71,7 @@ struct IntersynthBackend : public Backend {
 		log("http://www.clifford.at/intersynth/\n");
 		log("\n");
 	}
-	virtual void execute(std::ostream *&f, std::string filename, std::vector<std::string> args, RTLIL::Design *design)
+	void execute(std::ostream *&f, std::string filename, std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
 	{
 		log_header(design, "Executing INTERSYNTH backend.\n");
 		log_push();
diff --git a/backends/json/json.cc b/backends/json/json.cc
index d3b7077a2..f5c687981 100644
--- a/backends/json/json.cc
+++ b/backends/json/json.cc
@@ -93,8 +93,10 @@ struct JsonWriter
 				f << get_string(param.second.decode_string());
 			else if (GetSize(param.second.bits) > 32)
 				f << get_string(param.second.as_string());
-			else
+			else if ((param.second.flags & RTLIL::ConstFlags::CONST_FLAG_SIGNED) != 0)
 				f << stringf("%d", param.second.as_int());
+			else
+				f << stringf("%u", param.second.as_int());
 			first = false;
 		}
 	}
@@ -250,7 +252,7 @@ struct JsonWriter
 
 struct JsonBackend : public Backend {
 	JsonBackend() : Backend("json", "write design to a JSON file") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -458,7 +460,7 @@ struct JsonBackend : public Backend {
 		log("format. A program processing this format must ignore all unknown fields.\n");
 		log("\n");
 	}
-	virtual void execute(std::ostream *&f, std::string filename, std::vector<std::string> args, RTLIL::Design *design)
+	void execute(std::ostream *&f, std::string filename, std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
 	{
 		bool aig_mode = false;
 
@@ -482,7 +484,7 @@ struct JsonBackend : public Backend {
 
 struct JsonPass : public Pass {
 	JsonPass() : Pass("json", "write design in JSON format") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -499,7 +501,7 @@ struct JsonPass : public Pass {
 		log("See 'help write_json' for a description of the JSON format used.\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
 	{
 		std::string filename;
 		bool aig_mode = false;
diff --git a/backends/protobuf/protobuf.cc b/backends/protobuf/protobuf.cc
index 9a6fedee7..f56147cef 100644
--- a/backends/protobuf/protobuf.cc
+++ b/backends/protobuf/protobuf.cc
@@ -231,7 +231,7 @@ struct ProtobufDesignSerializer
 
 struct ProtobufBackend : public Backend {
 	ProtobufBackend(): Backend("protobuf", "write design to a Protocol Buffer file") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -249,7 +249,7 @@ struct ProtobufBackend : public Backend {
 		log("Yosys source code distribution.\n");
 		log("\n");
 	}
-	virtual void execute(std::ostream *&f, std::string filename, std::vector<std::string> args, RTLIL::Design *design)
+	void execute(std::ostream *&f, std::string filename, std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
 	{
 		bool aig_mode = false;
 		bool text_mode = false;
@@ -286,7 +286,7 @@ struct ProtobufBackend : public Backend {
 
 struct ProtobufPass : public Pass {
 	ProtobufPass() : Pass("protobuf", "write design in Protobuf format") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -307,7 +307,7 @@ struct ProtobufPass : public Pass {
 		log("Yosys source code distribution.\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
 	{
 		std::string filename;
 		bool aig_mode = false;
diff --git a/backends/simplec/simplec.cc b/backends/simplec/simplec.cc
index c9656caff..349bc5a6d 100644
--- a/backends/simplec/simplec.cc
+++ b/backends/simplec/simplec.cc
@@ -742,7 +742,7 @@ struct SimplecWorker
 
 struct SimplecBackend : public Backend {
 	SimplecBackend() : Backend("simplec", "convert design to simple C code") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -761,7 +761,7 @@ struct SimplecBackend : public Backend {
 		log("THIS COMMAND IS UNDER CONSTRUCTION\n");
 		log("\n");
 	}
-	virtual void execute(std::ostream *&f, std::string filename, std::vector<std::string> args, RTLIL::Design *design)
+	void execute(std::ostream *&f, std::string filename, std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
 	{
 		reserved_cids.clear();
 		id2cid.clear();
diff --git a/backends/smt2/Makefile.inc b/backends/smt2/Makefile.inc
index eacda2734..dce82f01a 100644
--- a/backends/smt2/Makefile.inc
+++ b/backends/smt2/Makefile.inc
@@ -6,7 +6,7 @@ ifneq ($(CONFIG),emcc)
 TARGETS += yosys-smtbmc
 
 yosys-smtbmc: backends/smt2/smtbmc.py
-	$(P) sed 's|##yosys-sys-path##|sys.path += [os.path.dirname(__file__) + p for p in ["/share/python3", "/../share/yosys/python3"]]|;' < $< > $@.new
+	$(P) sed 's|##yosys-sys-path##|sys.path += [os.path.dirname(os.path.realpath(__file__)) + p for p in ["/share/python3", "/../share/yosys/python3"]]|;' < $< > $@.new
 	$(Q) chmod +x $@.new
 	$(Q) mv $@.new $@
 
diff --git a/backends/smt2/smt2.cc b/backends/smt2/smt2.cc
index ca1ceacc7..e2777ae04 100644
--- a/backends/smt2/smt2.cc
+++ b/backends/smt2/smt2.cc
@@ -1251,7 +1251,7 @@ struct Smt2Worker
 
 struct Smt2Backend : public Backend {
 	Smt2Backend() : Backend("smt2", "write design to SMT-LIBv2 file") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -1407,7 +1407,7 @@ struct Smt2Backend : public Backend {
 		log("from non-zero to zero in the test design.\n");
 		log("\n");
 	}
-	virtual void execute(std::ostream *&f, std::string filename, std::vector<std::string> args, RTLIL::Design *design)
+	void execute(std::ostream *&f, std::string filename, std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
 	{
 		std::ifstream template_f;
 		bool bvmode = true, memmode = true, wiresmode = false, verbose = false, statebv = false, statedt = false;
diff --git a/backends/smt2/smtio.py b/backends/smt2/smtio.py
index 1a8d2484c..3fc823e3e 100644
--- a/backends/smt2/smtio.py
+++ b/backends/smt2/smtio.py
@@ -17,7 +17,9 @@
 #
 
 import sys, re, os, signal
-import resource, subprocess
+import subprocess
+if os.name == "posix":
+    import resource
 from copy import deepcopy
 from select import select
 from time import time
@@ -27,12 +29,13 @@ from threading import Thread
 
 # This is needed so that the recursive SMT2 S-expression parser
 # does not run out of stack frames when parsing large expressions
-smtio_reclimit = 64 * 1024
-smtio_stacksize = 128 * 1024 * 1024
-if sys.getrecursionlimit() < smtio_reclimit:
-    sys.setrecursionlimit(smtio_reclimit)
-if resource.getrlimit(resource.RLIMIT_STACK)[0] < smtio_stacksize:
-    resource.setrlimit(resource.RLIMIT_STACK, (smtio_stacksize, -1))
+if os.name == "posix":
+    smtio_reclimit = 64 * 1024
+    smtio_stacksize = 128 * 1024 * 1024
+    if sys.getrecursionlimit() < smtio_reclimit:
+        sys.setrecursionlimit(smtio_reclimit)
+    if resource.getrlimit(resource.RLIMIT_STACK)[0] < smtio_stacksize:
+        resource.setrlimit(resource.RLIMIT_STACK, (smtio_stacksize, -1))
 
 
 # currently running solvers (so we can kill them)
@@ -51,8 +54,9 @@ def force_shutdown(signum, frame):
             os.kill(p.pid, signal.SIGTERM)
     sys.exit(1)
 
+if os.name == "posix":
+    signal.signal(signal.SIGHUP, force_shutdown)
 signal.signal(signal.SIGINT, force_shutdown)
-signal.signal(signal.SIGHUP, force_shutdown)
 signal.signal(signal.SIGTERM, force_shutdown)
 
 def except_hook(exctype, value, traceback):
@@ -1053,4 +1057,3 @@ class MkVcd:
                     print("b0 %s" % self.nets[path][0], file=self.f)
                 else:
                     print("b1 %s" % self.nets[path][0], file=self.f)
-
diff --git a/backends/smv/smv.cc b/backends/smv/smv.cc
index 768969e6b..b8383412b 100644
--- a/backends/smv/smv.cc
+++ b/backends/smv/smv.cc
@@ -675,7 +675,7 @@ struct SmvWorker
 
 struct SmvBackend : public Backend {
 	SmvBackend() : Backend("smv", "write design to SMV file") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -693,7 +693,7 @@ struct SmvBackend : public Backend {
 		log("THIS COMMAND IS UNDER CONSTRUCTION\n");
 		log("\n");
 	}
-	virtual void execute(std::ostream *&f, std::string filename, std::vector<std::string> args, RTLIL::Design *design)
+	void execute(std::ostream *&f, std::string filename, std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
 	{
 		std::ifstream template_f;
 		bool verbose = false;
diff --git a/backends/spice/spice.cc b/backends/spice/spice.cc
index 4101cbf98..b6a3f1e77 100644
--- a/backends/spice/spice.cc
+++ b/backends/spice/spice.cc
@@ -132,7 +132,7 @@ static void print_spice_module(std::ostream &f, RTLIL::Module *module, RTLIL::De
 
 struct SpiceBackend : public Backend {
 	SpiceBackend() : Backend("spice", "write design to SPICE netlist file") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -161,7 +161,7 @@ struct SpiceBackend : public Backend {
 		log("        set the specified module as design top module\n");
 		log("\n");
 	}
-	virtual void execute(std::ostream *&f, std::string filename, std::vector<std::string> args, RTLIL::Design *design)
+	void execute(std::ostream *&f, std::string filename, std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
 	{
 		std::string top_module_name;
 		RTLIL::Module *top_module = NULL;
diff --git a/backends/table/table.cc b/backends/table/table.cc
index 27b7edfff..979273dd3 100644
--- a/backends/table/table.cc
+++ b/backends/table/table.cc
@@ -29,7 +29,7 @@ PRIVATE_NAMESPACE_BEGIN
 
 struct TableBackend : public Backend {
 	TableBackend() : Backend("table", "write design as connectivity table") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -48,7 +48,7 @@ struct TableBackend : public Backend {
 		log("module inputs and outputs are output using cell type and port '-' and with\n");
 		log("'pi' (primary input) or 'po' (primary output) or 'pio' as direction.\n");
 	}
-	virtual void execute(std::ostream *&f, std::string filename, std::vector<std::string> args, RTLIL::Design *design)
+	void execute(std::ostream *&f, std::string filename, std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
 	{
 		log_header(design, "Executing TABLE backend.\n");
 
diff --git a/backends/verilog/verilog_backend.cc b/backends/verilog/verilog_backend.cc
index b50dc12af..44e4e5f97 100644
--- a/backends/verilog/verilog_backend.cc
+++ b/backends/verilog/verilog_backend.cc
@@ -1482,7 +1482,7 @@ void dump_module(std::ostream &f, std::string indent, RTLIL::Module *module)
 
 struct VerilogBackend : public Backend {
 	VerilogBackend() : Backend("verilog", "write design to Verilog file") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -1550,7 +1550,7 @@ struct VerilogBackend : public Backend {
 		log("this command is called on a design with RTLIL processes.\n");
 		log("\n");
 	}
-	virtual void execute(std::ostream *&f, std::string filename, std::vector<std::string> args, RTLIL::Design *design)
+	void execute(std::ostream *&f, std::string filename, std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
 	{
 		log_header(design, "Executing Verilog backend.\n");
 
diff --git a/examples/basys3/example.xdc b/examples/basys3/example.xdc
index c1fd0e925..8cdaa1996 100644
--- a/examples/basys3/example.xdc
+++ b/examples/basys3/example.xdc
@@ -19,3 +19,6 @@ set_property -dict { IOSTANDARD LVCMOS33 PACKAGE_PIN L1  } [get_ports {LD[15]}]
 
 create_clock -add -name sys_clk_pin -period 10.00 -waveform {0 5} [get_ports CLK]
 
+set_property CONFIG_VOLTAGE 3.3 [current_design]
+set_property CFGBVS VCCO [current_design]
+
diff --git a/examples/basys3/run_prog.tcl b/examples/basys3/run_prog.tcl
index d711af840..b078ad511 100644
--- a/examples/basys3/run_prog.tcl
+++ b/examples/basys3/run_prog.tcl
@@ -1,3 +1,4 @@
+open_hw
 connect_hw_server
 open_hw_target [lindex [get_hw_targets] 0]
 set_property PROGRAM.FILE example.bit [lindex [get_hw_devices] 0]
diff --git a/examples/cxx-api/evaldemo.cc b/examples/cxx-api/evaldemo.cc
index e5cc8d8e7..34373487d 100644
--- a/examples/cxx-api/evaldemo.cc
+++ b/examples/cxx-api/evaldemo.cc
@@ -22,7 +22,7 @@ struct EvalDemoPass : public Pass
 {
 	EvalDemoPass() : Pass("evaldemo") { }
 
-	virtual void execute(vector<string>, Design *design)
+	void execute(vector<string>, Design *design) YS_OVERRIDE
 	{
 		Module *module = design->top_module();
 
diff --git a/frontends/ast/ast.cc b/frontends/ast/ast.cc
index 999202b47..7c72a50d9 100644
--- a/frontends/ast/ast.cc
+++ b/frontends/ast/ast.cc
@@ -171,8 +171,8 @@ 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 +191,10 @@ 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;
+	was_checked = false;
 	range_valid = false;
 	range_swapped = false;
 	port_id = 0;
@@ -285,7 +287,9 @@ 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");
@@ -652,6 +656,8 @@ 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)
@@ -955,8 +961,8 @@ static AstModule* process_module(AstNode *ast, bool defer)
 
 		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++) {
@@ -1044,8 +1050,8 @@ 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);
+					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);
@@ -1197,4 +1203,3 @@ void AST::use_internal_line_num()
 }
 
 YOSYS_NAMESPACE_END
-
diff --git a/frontends/ast/ast.h b/frontends/ast/ast.h
index 756629aca..d94199643 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>
@@ -168,7 +168,7 @@ 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, range_valid, range_swapped, was_checked;
 		int port_id, range_left, range_right;
 		uint32_t integer;
 		double realvalue;
@@ -282,9 +282,9 @@ namespace AST
 	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;
+		~AstModule() YS_OVERRIDE;
+		RTLIL::IdString derive(RTLIL::Design *design, dict<RTLIL::IdString, RTLIL::Const> parameters, bool mayfail) YS_OVERRIDE;
+		RTLIL::Module *clone() const YS_OVERRIDE;
 	};
 
 	// this must be set by the language frontend before parsing the sources
diff --git a/frontends/ast/genrtlil.cc b/frontends/ast/genrtlil.cc
index d9f0039af..0f7e910f3 100644
--- a/frontends/ast/genrtlil.cc
+++ b/frontends/ast/genrtlil.cc
@@ -55,8 +55,8 @@ 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 +89,8 @@ 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 +117,8 @@ 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 +152,8 @@ 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 +207,8 @@ 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 +238,7 @@ 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 +253,12 @@ 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 +480,8 @@ 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();
 				}
 
@@ -549,12 +549,12 @@ 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 wire declaration in block without label!\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 +602,7 @@ 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 +612,7 @@ 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 +624,7 @@ 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 +635,10 @@ 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;
 		} 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;
@@ -648,8 +648,8 @@ 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);
+					log_file_error(filename, linenum, "Unsupported expression on dynamic range select on signal `%s'!\n",
+						       str.c_str());
 				this_width = left_at_zero_ast->integer - right_at_zero_ast->integer + 1;
 				delete left_at_zero_ast;
 				delete right_at_zero_ast;
@@ -665,7 +665,7 @@ 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 +693,7 @@ 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 +767,7 @@ 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 +777,8 @@ 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;
@@ -799,8 +799,8 @@ void AstNode::detectSignWidthWorker(int &width_hint, bool &sign_hint, bool *foun
 	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);
+		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)
@@ -863,11 +863,11 @@ RTLIL::SigSpec AstNode::genRTLIL(int width_hint, bool sign_hint)
 	// 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));
 
@@ -881,8 +881,8 @@ 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();
 			}
 		}
@@ -891,16 +891,16 @@ RTLIL::SigSpec AstNode::genRTLIL(int width_hint, bool sign_hint)
 	// 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 +917,8 @@ 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();
 			}
 		}
@@ -937,8 +937,8 @@ RTLIL::SigSpec AstNode::genRTLIL(int width_hint, bool sign_hint)
 	case AST_REALVALUE:
 		{
 			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;
 		}
 
@@ -958,25 +958,25 @@ 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);
+				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());
 
 			wire = current_module->wires_[str];
 			chunk.wire = wire;
@@ -994,8 +994,8 @@ 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);
+						log_file_error(filename, linenum, "Unsupported expression on dynamic range select on signal `%s'!\n",
+							       str.c_str());
 					int width = 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());
@@ -1023,11 +1023,11 @@ 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 out of bounds on signal `%s': Setting all %d result bits to undef.\n",
+									str.c_str(), chunk.width);
 						chunk = RTLIL::SigChunk(RTLIL::State::Sx, chunk.width);
 					} else {
 						if (chunk.width + chunk.offset > source_width) {
@@ -1040,11 +1040,11 @@ 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 select out of bounds on signal `%s': Setting %d LSB bits to undef.\n",
+									 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 select out of bounds on signal `%s': Setting %d MSB bits to undef.\n",
+									 str.c_str(), add_undef_bits_msb);
 					}
 				}
 			}
@@ -1083,7 +1083,7 @@ 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 +1322,7 @@ 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);
 			}
@@ -1379,8 +1379,8 @@ 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();
 			}
 
@@ -1401,10 +1401,10 @@ 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"
-						"    old assignment: %s = %s\n    new assignment: %s = %s.\n",
-						filename.c_str(), linenum, log_signal(left), log_signal(right),
-						log_signal(new_left), log_signal(new_right));
+				log_file_warning(filename, linenum, "Ignoring assignment to constant bits:\n"
+						 "    old assignment: %s = %s\n    new assignment: %s = %s.\n",
+						 log_signal(left), log_signal(right),
+						 log_signal(new_left), log_signal(new_right));
 				left = new_left;
 				right = new_right;
 			}
@@ -1418,8 +1418,7 @@ 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);
@@ -1435,16 +1434,15 @@ RTLIL::SigSpec AstNode::genRTLIL(int width_hint, bool sign_hint)
 				if (child->type == AST_PARASET) {
 					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);
 						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();
 					continue;
 				}
@@ -1465,8 +1463,8 @@ 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();
 			}
 		}
@@ -1493,19 +1491,19 @@ 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 +1512,7 @@ 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();
 				}
 
@@ -1532,8 +1530,8 @@ RTLIL::SigSpec AstNode::genRTLIL(int width_hint, bool sign_hint)
 		for (auto f : log_files)
 			current_ast->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 +1561,3 @@ 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..04c429f7f 100644
--- a/frontends/ast/simplify.cc
+++ b/frontends/ast/simplify.cc
@@ -177,13 +177,13 @@ 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 +195,14 @@ 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 +215,7 @@ 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 +239,13 @@ 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 +253,7 @@ 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;
 				}
 
@@ -327,6 +327,8 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 			if (node->type == AST_WIRE) {
 				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 +363,8 @@ 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 +378,7 @@ 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 +406,7 @@ 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 +444,16 @@ 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)
+				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 +465,7 @@ 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;
@@ -695,7 +709,7 @@ 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 +726,13 @@ 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 +746,7 @@ 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 +762,9 @@ 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 +828,7 @@ 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 +846,7 @@ 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 +875,12 @@ 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;
@@ -924,7 +938,7 @@ 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);
@@ -949,6 +963,7 @@ 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 +988,10 @@ 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);
+		log_file_error(filename, linenum, "Repeat loops are only allowed in constant functions!\n");
 
 	// unroll for loops and generate-for blocks
 	if ((type == AST_GENFOR || type == AST_FOR) && children.size() != 0)
@@ -991,31 +1006,31 @@ 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)) { }
 
 		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;
@@ -1037,7 +1052,7 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 			while (buf->simplify(true, false, false, stage, width_hint, 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;
@@ -1078,7 +1093,7 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 			while (buf->simplify(true, false, false, stage, 32, true, false)) { }
 
 			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;
@@ -1095,8 +1110,7 @@ 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 +1158,7 @@ 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 +1199,7 @@ 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 +1233,7 @@ 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 +1274,7 @@ 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 +1285,7 @@ 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 +1299,8 @@ 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 +1315,8 @@ 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);
 
@@ -1387,8 +1401,8 @@ 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;
@@ -1415,16 +1429,19 @@ 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)) { }
@@ -1434,9 +1451,11 @@ skip_dynamic_range_lvalue_expansion:;
 
 		AstNode *assign_check = new AstNode(AST_ASSIGN_LE, new AstNode(AST_IDENTIFIER), mkconst_bits(x_bit, false));
 		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);
@@ -1445,6 +1464,7 @@ skip_dynamic_range_lvalue_expansion:;
 
 		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));
@@ -1453,6 +1473,7 @@ 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);
@@ -1561,12 +1582,14 @@ 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 +1599,7 @@ 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 +1615,17 @@ 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 +1637,7 @@ 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 +1652,14 @@ 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 +1675,13 @@ 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);
+					log_file_error(filename, linenum, "Unsupported expression on dynamic range select on signal `%s'!\n", str.c_str());
 				int width = 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 +1689,7 @@ 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 +1701,12 @@ 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;
 			}
 		}
 
@@ -1737,19 +1771,19 @@ skip_dynamic_range_lvalue_expansion:;
 				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)) { }
 					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;
@@ -1805,12 +1839,12 @@ skip_dynamic_range_lvalue_expansion:;
 			if (str == "\\$stable" || str == "\\$rose" || str == "\\$fell")
 			{
 				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();
@@ -1840,13 +1874,13 @@ 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())
@@ -1865,12 +1899,12 @@ skip_dynamic_range_lvalue_expansion:;
 			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 +1927,7 @@ 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 $bits() return the expression width
@@ -1901,15 +1935,15 @@ skip_dynamic_range_lvalue_expansion:;
 						if (str == "\\$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 +1954,9 @@ 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 +1977,19 @@ 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 +1999,8 @@ 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 +2052,14 @@ 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 +2071,7 @@ 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 +2079,26 @@ 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 +2106,7 @@ 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 +2114,7 @@ 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));
 				}
 
@@ -2106,7 +2140,7 @@ skip_dynamic_range_lvalue_expansion:;
 			}
 
 			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];
@@ -2134,9 +2168,9 @@ 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;
@@ -2253,7 +2287,7 @@ 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());
 						}
 					}
 				}
@@ -2641,7 +2675,7 @@ 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;
@@ -2687,7 +2721,7 @@ 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;
 			}
 
@@ -2943,7 +2977,7 @@ 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;
 }
@@ -3008,6 +3042,7 @@ 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 +3050,7 @@ 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);
@@ -3083,6 +3119,7 @@ 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 +3128,7 @@ 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 +3137,7 @@ 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 +3148,7 @@ 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 +3161,7 @@ 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);
 
@@ -3202,13 +3243,13 @@ 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);
 		}
@@ -3247,8 +3288,8 @@ AstNode *AstNode::eval_const_function(AstNode *fcall)
 		{
 			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;
@@ -3291,24 +3332,24 @@ 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 +3380,8 @@ 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 +3401,8 @@ 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 +3439,8 @@ 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;
@@ -3428,8 +3469,8 @@ 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();
 	}
 
@@ -3446,4 +3487,3 @@ AstNode *AstNode::eval_const_function(AstNode *fcall)
 }
 
 YOSYS_NAMESPACE_END
-
diff --git a/frontends/blif/blifparse.cc b/frontends/blif/blifparse.cc
index e6bb99954..034b3e70c 100644
--- a/frontends/blif/blifparse.cc
+++ b/frontends/blif/blifparse.cc
@@ -83,7 +83,9 @@ void parse_blif(RTLIL::Design *design, std::istream &f, std::string dff_name, bo
 	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 primative 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;
 			}
@@ -546,11 +574,13 @@ 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");
@@ -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/ilang/ilang_frontend.cc b/frontends/ilang/ilang_frontend.cc
index ed6789987..d8783ac1d 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");
@@ -45,7 +45,7 @@ struct IlangFrontend : public Frontend {
 		log("representation of a design in yosys's internal 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 ILANG frontend.\n");
 		extra_args(f, filename, args, 1);
diff --git a/frontends/json/jsonparse.cc b/frontends/json/jsonparse.cc
index 629578c61..82361ea9b 100644
--- a/frontends/json/jsonparse.cc
+++ b/frontends/json/jsonparse.cc
@@ -494,7 +494,7 @@ 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 +504,7 @@ 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..0a5bd84de 100644
--- a/frontends/liberty/liberty.cc
+++ b/frontends/liberty/liberty.cc
@@ -452,7 +452,7 @@ 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 +485,7 @@ 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;
diff --git a/frontends/verific/verific.cc b/frontends/verific/verific.cc
index 8937cdde8..b8c0375ce 100644
--- a/frontends/verific/verific.cc
+++ b/frontends/verific/verific.cc
@@ -1685,7 +1685,7 @@ bool check_noverific_env()
 
 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");
@@ -1732,6 +1732,15 @@ 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");
@@ -1784,21 +1793,34 @@ 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("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);
+
+			// 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);
+
+			set_verific_global_flags = false;
+		}
 
 		verific_verbose = 0;
 
@@ -1816,6 +1838,28 @@ struct VerificPass : public Pass {
 
 		int argidx = 1;
 
+		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++)
 				verific_incdirs.push_back(args[argidx]);
@@ -2162,7 +2206,7 @@ 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
@@ -2170,7 +2214,7 @@ 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");
@@ -2203,7 +2247,7 @@ struct ReadPass : public Pass {
 		log("Add directory to global Verilog/SystemVerilog include directories.\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)
 			log_cmd_error("Missing mode parameter.\n");
diff --git a/frontends/verilog/const2ast.cc b/frontends/verilog/const2ast.cc
index 4a58357bf..7848c626d 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;
@@ -105,8 +104,8 @@ static void my_strtobin(std::vector<RTLIL::State> &data, const char *str, int le
 		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)
@@ -238,4 +237,3 @@ AstNode *VERILOG_FRONTEND::const2ast(std::string code, char case_type, bool warn
 }
 
 YOSYS_NAMESPACE_END
-
diff --git a/frontends/verilog/verilog_frontend.cc b/frontends/verilog/verilog_frontend.cc
index 505c94619..911e36112 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");
@@ -180,7 +180,7 @@ 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;
@@ -395,7 +395,7 @@ 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 +416,7 @@ 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 +453,7 @@ 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 +469,7 @@ 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 +519,11 @@ 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_lexer.l b/frontends/verilog/verilog_lexer.l
index d12c9ee4e..0134416c1 100644
--- a/frontends/verilog/verilog_lexer.l
+++ b/frontends/verilog/verilog_lexer.l
@@ -192,7 +192,7 @@ 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); }
+"logic"      { SV_KEYWORD(TOK_LOGIC); }
 "bit"        { SV_KEYWORD(TOK_REG); }
 
 "eventually"   { if (formal_mode) return TOK_EVENTUALLY; SV_KEYWORD(TOK_EVENTUALLY); }
diff --git a/frontends/verilog/verilog_parser.y b/frontends/verilog/verilog_parser.y
index e803d8072..78cac5543 100644
--- a/frontends/verilog/verilog_parser.y
+++ b/frontends/verilog/verilog_parser.y
@@ -105,7 +105,7 @@ static void free_attr(std::map<std::string, AstNode*> *al)
 %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_INPUT TOK_OUTPUT TOK_INOUT TOK_WIRE 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
@@ -376,9 +376,10 @@ 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 +389,17 @@ wire_type_token:
 	TOK_INOUT {
 		astbuf3->is_input = true;
 		astbuf3->is_output = true;
-	} |
+	};
+
+wire_type_token:
 	TOK_WIRE {
 	} |
 	TOK_REG {
 		astbuf3->is_reg = true;
 	} |
+	TOK_LOGIC {
+		astbuf3->is_logic = true;
+	} |
 	TOK_INTEGER {
 		astbuf3->is_reg = true;
 		astbuf3->range_left = 31;
@@ -545,6 +551,7 @@ 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;
@@ -1024,6 +1031,7 @@ wire_name:
 				node->port_id = current_function_or_task_port_id++;
 		}
 		ast_stack.back()->children.push_back(node);
+
 		delete $1;
 	};
 
diff --git a/kernel/celledges.h b/kernel/celledges.h
index 6aab9ed43..2cc297cb2 100644
--- a/kernel/celledges.h
+++ b/kernel/celledges.h
@@ -1,4 +1,4 @@
-/*
+/* -*- c++ -*-
  *  yosys -- Yosys Open SYnthesis Suite
  *
  *  Copyright (C) 2012  Clifford Wolf <clifford@clifford.at>
@@ -38,7 +38,7 @@ struct FwdCellEdgesDatabase : AbstractCellEdgesDatabase
 	dict<SigBit, pool<SigBit>> db;
 	FwdCellEdgesDatabase(SigMap &sigmap) : sigmap(sigmap) { }
 
-	virtual void add_edge(RTLIL::Cell *cell, RTLIL::IdString from_port, int from_bit, RTLIL::IdString to_port, int to_bit, int) override {
+	void add_edge(RTLIL::Cell *cell, RTLIL::IdString from_port, int from_bit, RTLIL::IdString to_port, int to_bit, int) YS_OVERRIDE {
 		SigBit from_sigbit = sigmap(cell->getPort(from_port)[from_bit]);
 		SigBit to_sigbit = sigmap(cell->getPort(to_port)[to_bit]);
 		db[from_sigbit].insert(to_sigbit);
@@ -51,7 +51,7 @@ struct RevCellEdgesDatabase : AbstractCellEdgesDatabase
 	dict<SigBit, pool<SigBit>> db;
 	RevCellEdgesDatabase(SigMap &sigmap) : sigmap(sigmap) { }
 
-	virtual void add_edge(RTLIL::Cell *cell, RTLIL::IdString from_port, int from_bit, RTLIL::IdString to_port, int to_bit, int) override {
+	void add_edge(RTLIL::Cell *cell, RTLIL::IdString from_port, int from_bit, RTLIL::IdString to_port, int to_bit, int) YS_OVERRIDE {
 		SigBit from_sigbit = sigmap(cell->getPort(from_port)[from_bit]);
 		SigBit to_sigbit = sigmap(cell->getPort(to_port)[to_bit]);
 		db[to_sigbit].insert(from_sigbit);
diff --git a/kernel/log.cc b/kernel/log.cc
index 6d562b9e6..0ee2170a0 100644
--- a/kernel/log.cc
+++ b/kernel/log.cc
@@ -203,7 +203,8 @@ void logv_header(RTLIL::Design *design, const char *format, va_list ap)
 		log_files.pop_back();
 }
 
-void logv_warning(const char *format, va_list ap)
+static void logv_warning_with_prefix(const char *prefix,
+                                     const char *format, va_list ap)
 {
 	std::string message = vstringf(format, ap);
 	bool suppressed = false;
@@ -214,7 +215,7 @@ void logv_warning(const char *format, va_list ap)
 
 	if (suppressed)
 	{
-		log("Suppressed warning: %s", message.c_str());
+		log("Suppressed %s%s", prefix, message.c_str());
 	}
 	else
 	{
@@ -224,7 +225,7 @@ void logv_warning(const char *format, va_list ap)
 
 		if (log_warnings.count(message))
 		{
-			log("Warning: %s", message.c_str());
+			log("%s%s", prefix, message.c_str());
 			log_flush();
 		}
 		else
@@ -232,7 +233,7 @@ void logv_warning(const char *format, va_list ap)
 			if (log_errfile != NULL && !log_quiet_warnings)
 				log_files.push_back(log_errfile);
 
-			log("Warning: %s", message.c_str());
+			log("%s%s", prefix, message.c_str());
 			log_flush();
 
 			if (log_errfile != NULL && !log_quiet_warnings)
@@ -245,49 +246,30 @@ void logv_warning(const char *format, va_list ap)
 	}
 }
 
-void logv_warning_noprefix(const char *format, va_list ap)
+void logv_warning(const char *format, va_list ap)
 {
-	std::string message = vstringf(format, ap);
-	bool suppressed = false;
-
-	for (auto &re : log_nowarn_regexes)
-		if (std::regex_search(message, re))
-			suppressed = true;
-
-	if (suppressed)
-	{
-		log("%s", message.c_str());
-	}
-	else
-	{
-		for (auto &re : log_werror_regexes)
-			if (std::regex_search(message, re))
-				log_error("%s",  message.c_str());
-
-		if (log_warnings.count(message))
-		{
-			log("%s", message.c_str());
-			log_flush();
-		}
-		else
-		{
-			if (log_errfile != NULL && !log_quiet_warnings)
-				log_files.push_back(log_errfile);
-
-			log("%s", message.c_str());
-			log_flush();
-
-			if (log_errfile != NULL && !log_quiet_warnings)
-				log_files.pop_back();
+	logv_warning_with_prefix("Warning: ", format, ap);
+}
 
-			log_warnings.insert(message);
-		}
+void logv_warning_noprefix(const char *format, va_list ap)
+{
+	logv_warning_with_prefix("", format, ap);
+}
 
-		log_warnings_count++;
-	}
+void log_file_warning(const std::string &filename, int lineno,
+                      const char *format, ...)
+{
+	va_list ap;
+	va_start(ap, format);
+	std::string prefix = stringf("%s:%d: Warning: ",
+				     filename.c_str(), lineno);
+	logv_warning_with_prefix(prefix.c_str(), format, ap);
+	va_end(ap);
 }
 
-void logv_error(const char *format, va_list ap)
+YS_ATTRIBUTE(noreturn)
+static void logv_error_with_prefix(const char *prefix,
+                                   const char *format, va_list ap)
 {
 #ifdef EMSCRIPTEN
 	auto backup_log_files = log_files;
@@ -302,7 +284,7 @@ void logv_error(const char *format, va_list ap)
 				f = stderr;
 
 	log_last_error = vstringf(format, ap);
-	log("ERROR: %s", log_last_error.c_str());
+	log("%s%s", prefix, log_last_error.c_str());
 	log_flush();
 
 	if (log_error_atexit)
@@ -318,6 +300,21 @@ void logv_error(const char *format, va_list ap)
 #endif
 }
 
+void logv_error(const char *format, va_list ap)
+{
+	logv_error_with_prefix("ERROR: ", format, ap);
+}
+
+void log_file_error(const string &filename, int lineno,
+                    const char *format, ...)
+{
+	va_list ap;
+	va_start(ap, format);
+	std::string prefix = stringf("%s:%d: ERROR: ",
+				     filename.c_str(), lineno);
+	logv_error_with_prefix(prefix.c_str(), format, ap);
+}
+
 void log(const char *format, ...)
 {
 	va_list ap;
@@ -636,4 +633,3 @@ dict<std::string, std::pair<std::string, int>> get_coverage_data()
 #endif
 
 YOSYS_NAMESPACE_END
-
diff --git a/kernel/log.h b/kernel/log.h
index a2aacfd4d..0b4905c3a 100644
--- a/kernel/log.h
+++ b/kernel/log.h
@@ -73,8 +73,13 @@ YS_NORETURN void logv_error(const char *format, va_list ap) YS_ATTRIBUTE(noretur
 void log(const char *format, ...)  YS_ATTRIBUTE(format(printf, 1, 2));
 void log_header(RTLIL::Design *design, const char *format, ...) YS_ATTRIBUTE(format(printf, 2, 3));
 void log_warning(const char *format, ...) YS_ATTRIBUTE(format(printf, 1, 2));
+
+// Log with filename to report a problem in a source file.
+void log_file_warning(const std::string &filename, int lineno, const char *format, ...) YS_ATTRIBUTE(format(printf, 3, 4));
+
 void log_warning_noprefix(const char *format, ...) YS_ATTRIBUTE(format(printf, 1, 2));
 YS_NORETURN void log_error(const char *format, ...) YS_ATTRIBUTE(format(printf, 1, 2), noreturn);
+void log_file_error(const string &filename, int lineno, const char *format, ...) YS_ATTRIBUTE(format(printf, 3, 4), noreturn);
 YS_NORETURN void log_cmd_error(const char *format, ...) YS_ATTRIBUTE(format(printf, 1, 2), noreturn);
 
 void log_spacer();
diff --git a/kernel/modtools.h b/kernel/modtools.h
index ffcb48d44..409562eb9 100644
--- a/kernel/modtools.h
+++ b/kernel/modtools.h
@@ -1,4 +1,4 @@
-/*
+/* -*- c++ -*-
  *  yosys -- Yosys Open SYnthesis Suite
  *
  *  Copyright (C) 2012  Clifford Wolf <clifford@clifford.at>
@@ -158,7 +158,7 @@ struct ModIndex : public RTLIL::Monitor
 #endif
 	}
 
-	virtual void notify_connect(RTLIL::Cell *cell, const RTLIL::IdString &port, const RTLIL::SigSpec &old_sig, RTLIL::SigSpec &sig) YS_OVERRIDE
+	void notify_connect(RTLIL::Cell *cell, const RTLIL::IdString &port, const RTLIL::SigSpec &old_sig, RTLIL::SigSpec &sig) YS_OVERRIDE
 	{
 		log_assert(module == cell->module);
 
@@ -169,7 +169,7 @@ struct ModIndex : public RTLIL::Monitor
 		port_add(cell, port, sig);
 	}
 
-	virtual void notify_connect(RTLIL::Module *mod YS_ATTRIBUTE(unused), const RTLIL::SigSig &sigsig) YS_OVERRIDE
+	void notify_connect(RTLIL::Module *mod YS_ATTRIBUTE(unused), const RTLIL::SigSig &sigsig) YS_OVERRIDE
 	{
 		log_assert(module == mod);
 
@@ -214,13 +214,13 @@ struct ModIndex : public RTLIL::Monitor
 		}
 	}
 
-	virtual void notify_connect(RTLIL::Module *mod YS_ATTRIBUTE(unused), const std::vector<RTLIL::SigSig>&) YS_OVERRIDE
+	void notify_connect(RTLIL::Module *mod YS_ATTRIBUTE(unused), const std::vector<RTLIL::SigSig>&) YS_OVERRIDE
 	{
 		log_assert(module == mod);
 		auto_reload_module = true;
 	}
 
-	virtual void notify_blackout(RTLIL::Module *mod YS_ATTRIBUTE(unused)) YS_OVERRIDE
+	void notify_blackout(RTLIL::Module *mod YS_ATTRIBUTE(unused)) YS_OVERRIDE
 	{
 		log_assert(module == mod);
 		auto_reload_module = true;
diff --git a/kernel/register.cc b/kernel/register.cc
index e30414f44..402a5b3ea 100644
--- a/kernel/register.cc
+++ b/kernel/register.cc
@@ -615,7 +615,7 @@ static struct CellHelpMessages {
 
 struct HelpPass : public Pass {
 	HelpPass() : Pass("help", "display help messages") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		log("\n");
 		log("    help  ................  list all commands\n");
@@ -684,7 +684,7 @@ struct HelpPass : public Pass {
 
 		fclose(f);
 	}
-	virtual void execute(std::vector<std::string> args, RTLIL::Design*)
+	void execute(std::vector<std::string> args, RTLIL::Design*) YS_OVERRIDE
 	{
 		if (args.size() == 1) {
 			log("\n");
@@ -768,7 +768,7 @@ struct HelpPass : public Pass {
 
 struct EchoPass : public Pass {
 	EchoPass() : Pass("echo", "turning echoing back of commands on and off") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		log("\n");
 		log("    echo on\n");
@@ -781,7 +781,7 @@ struct EchoPass : public Pass {
 		log("Do not print all commands to log before executing them. (default)\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, 2, "Unexpected argument.");
@@ -806,10 +806,9 @@ struct MinisatSatSolver : public SatSolver {
 	MinisatSatSolver() : SatSolver("minisat") {
 		yosys_satsolver = this;
 	}
-	virtual ezSAT *create() YS_OVERRIDE {
+	ezSAT *create() YS_OVERRIDE {
 		return new ezMiniSAT();
 	}
 } MinisatSatSolver;
 
 YOSYS_NAMESPACE_END
-
diff --git a/kernel/register.h b/kernel/register.h
index 8024c56a0..c74029823 100644
--- a/kernel/register.h
+++ b/kernel/register.h
@@ -1,4 +1,4 @@
-/*
+/* -*- c++ -*-
  *  yosys -- Yosys Open SYnthesis Suite
  *
  *  Copyright (C) 2012  Clifford Wolf <clifford@clifford.at>
@@ -88,9 +88,9 @@ struct Frontend : Pass
 
 	std::string frontend_name;
 	Frontend(std::string name, std::string short_help = "** document me **");
-	virtual void run_register() YS_OVERRIDE;
-	virtual ~Frontend();
-	virtual void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE YS_FINAL;
+	void run_register() YS_OVERRIDE;
+	~Frontend() YS_OVERRIDE;
+	void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE YS_FINAL;
 	virtual void execute(std::istream *&f, std::string filename, std::vector<std::string> args, RTLIL::Design *design) = 0;
 
 	static std::vector<std::string> next_args;
@@ -104,9 +104,9 @@ struct Backend : Pass
 {
 	std::string backend_name;
 	Backend(std::string name, std::string short_help = "** document me **");
-	virtual void run_register() YS_OVERRIDE;
-	virtual ~Backend();
-	virtual void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE YS_FINAL;
+	void run_register() YS_OVERRIDE;
+	~Backend() YS_OVERRIDE;
+	void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE YS_FINAL;
 	virtual void execute(std::ostream *&f, std::string filename,  std::vector<std::string> args, RTLIL::Design *design) = 0;
 
 	void extra_args(std::ostream *&f, std::string &filename, std::vector<std::string> args, size_t argidx);
diff --git a/kernel/rtlil.h b/kernel/rtlil.h
index 54d0b8c22..027faf416 100644
--- a/kernel/rtlil.h
+++ b/kernel/rtlil.h
@@ -1,4 +1,4 @@
-/*
+/* -*- c++ -*-
  *  yosys -- Yosys Open SYnthesis Suite
  *
  *  Copyright (C) 2012  Clifford Wolf <clifford@clifford.at>
diff --git a/kernel/satgen.h b/kernel/satgen.h
index 8d760fff7..210cca3f3 100644
--- a/kernel/satgen.h
+++ b/kernel/satgen.h
@@ -1,4 +1,4 @@
-/*
+/* -*- c++ -*-
  *  yosys -- Yosys Open SYnthesis Suite
  *
  *  Copyright (C) 2012  Clifford Wolf <clifford@clifford.at>
diff --git a/kernel/yosys.cc b/kernel/yosys.cc
index 750a154e6..264b1f63d 100644
--- a/kernel/yosys.cc
+++ b/kernel/yosys.cc
@@ -636,7 +636,7 @@ extern Tcl_Interp *yosys_get_tcl_interp()
 
 struct TclPass : public Pass {
 	TclPass() : Pass("tcl", "execute a TCL script file") { }
-	virtual void help() {
+	void help() YS_OVERRIDE {
 		log("\n");
 		log("    tcl <filename>\n");
 		log("\n");
@@ -649,7 +649,7 @@ struct TclPass : public Pass {
 		log("in order to avoid a name collision with the built in commands.\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)
 			log_cmd_error("Missing script file.\n");
 		if (args.size() > 2)
@@ -825,6 +825,8 @@ void run_frontend(std::string filename, std::string command, std::string *backen
 			command = "vhdl";
 		else if (filename.size() > 4 && filename.substr(filename.size()-5) == ".blif")
 			command = "blif";
+		else if (filename.size() > 5 && filename.substr(filename.size()-6) == ".eblif")
+			command = "blif";
 		else if (filename.size() > 4 && filename.substr(filename.size()-5) == ".json")
 			command = "json";
 		else if (filename.size() > 3 && filename.substr(filename.size()-3) == ".il")
@@ -1111,7 +1113,7 @@ void shell(RTLIL::Design *design)
 
 struct ShellPass : public Pass {
 	ShellPass() : Pass("shell", "enter interactive command mode") { }
-	virtual void help() {
+	void help() YS_OVERRIDE {
 		log("\n");
 		log("    shell\n");
 		log("\n");
@@ -1143,7 +1145,7 @@ struct ShellPass : public Pass {
 		log("Press Ctrl-D or type 'exit' to leave the interactive shell.\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 {
 		extra_args(args, 1, design, false);
 		shell(design);
 	}
@@ -1152,7 +1154,7 @@ struct ShellPass : public Pass {
 #if defined(YOSYS_ENABLE_READLINE) || defined(YOSYS_ENABLE_EDITLINE)
 struct HistoryPass : public Pass {
 	HistoryPass() : Pass("history", "show last interactive commands") { }
-	virtual void help() {
+	void help() YS_OVERRIDE {
 		log("\n");
 		log("    history\n");
 		log("\n");
@@ -1161,7 +1163,7 @@ struct HistoryPass : public Pass {
 		log("from executed scripts.\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 {
 		extra_args(args, 1, design, false);
 #ifdef YOSYS_ENABLE_READLINE
 		for(HIST_ENTRY **list = history_list(); *list != NULL; list++)
@@ -1176,7 +1178,7 @@ struct HistoryPass : public Pass {
 
 struct ScriptCmdPass : public Pass {
 	ScriptCmdPass() : Pass("script", "execute commands from script file") { }
-	virtual void help() {
+	void help() YS_OVERRIDE {
 		log("\n");
 		log("    script <filename> [<from_label>:<to_label>]\n");
 		log("\n");
@@ -1191,7 +1193,7 @@ struct ScriptCmdPass : public Pass {
 		log("marked with that label (until the next label) is executed.\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)
 			log_cmd_error("Missing script file.\n");
 		else if (args.size() == 2)
diff --git a/kernel/yosys.h b/kernel/yosys.h
index 14cbcd610..c9f973318 100644
--- a/kernel/yosys.h
+++ b/kernel/yosys.h
@@ -1,4 +1,4 @@
-/*
+/* -*- c++ -*-
  *  yosys -- Yosys Open SYnthesis Suite
  *
  *  Copyright (C) 2012  Clifford Wolf <clifford@clifford.at>
diff --git a/manual/CHAPTER_Prog/stubnets.cc b/manual/CHAPTER_Prog/stubnets.cc
index eb77bd404..8123e63db 100644
--- a/manual/CHAPTER_Prog/stubnets.cc
+++ b/manual/CHAPTER_Prog/stubnets.cc
@@ -98,7 +98,7 @@ static void find_stub_nets(RTLIL::Design *design, RTLIL::Module *module, bool re
 // each pass contains a singleton object that is derived from Pass
 struct StubnetsPass : public Pass {
 	StubnetsPass() : Pass("stubnets") { }
-	virtual void execute(std::vector<std::string> args, RTLIL::Design *design)
+	void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
 	{
 		// variables to mirror information from passed options
 		bool report_bits = 0;
diff --git a/manual/PRESENTATION_Prog/my_cmd.cc b/manual/PRESENTATION_Prog/my_cmd.cc
index d99bfe1e8..5d9a7e13b 100644
--- a/manual/PRESENTATION_Prog/my_cmd.cc
+++ b/manual/PRESENTATION_Prog/my_cmd.cc
@@ -6,7 +6,7 @@ PRIVATE_NAMESPACE_BEGIN
 
 struct MyPass : public Pass {
     MyPass() : Pass("my_cmd", "just a simple test") { }
-    virtual void execute(std::vector<std::string> args, RTLIL::Design *design)
+    void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
     {
         log("Arguments to my_cmd:\n");
         for (auto &arg : args)
@@ -22,7 +22,7 @@ struct MyPass : public Pass {
 
 struct Test1Pass : public Pass {
     Test1Pass() : Pass("test1", "creating the absval module") { }
-    virtual void execute(std::vector<std::string>, RTLIL::Design *design)
+    void execute(std::vector<std::string>, RTLIL::Design *design) YS_OVERRIDE
     {
         if (design->has("\\absval") != 0)
             log_error("A module with the name absval already exists!\n");
@@ -49,7 +49,7 @@ struct Test1Pass : public Pass {
 
 struct Test2Pass : public Pass {
     Test2Pass() : Pass("test2", "demonstrating sigmap on test module") { }
-    virtual void execute(std::vector<std::string>, RTLIL::Design *design)
+    void execute(std::vector<std::string>, RTLIL::Design *design) YS_OVERRIDE
     {
         if (design->selection_stack.back().empty())
             log_cmd_error("This command can't operator on an empty selection!\n");
diff --git a/passes/cmds/add.cc b/passes/cmds/add.cc
index e698926f9..cfccca966 100644
--- a/passes/cmds/add.cc
+++ b/passes/cmds/add.cc
@@ -83,7 +83,7 @@ static void add_wire(RTLIL::Design *design, RTLIL::Module *module, std::string n
 
 struct AddPass : public Pass {
 	AddPass() : Pass("add", "add objects to the design") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -106,7 +106,7 @@ struct AddPass : public Pass {
 		log("selected modules.\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
 	{
 		std::string command;
 		std::string arg_name;
diff --git a/passes/cmds/blackbox.cc b/passes/cmds/blackbox.cc
index 497b35f5c..6094f8f16 100644
--- a/passes/cmds/blackbox.cc
+++ b/passes/cmds/blackbox.cc
@@ -24,7 +24,7 @@ PRIVATE_NAMESPACE_BEGIN
 
 struct BlackboxPass : public Pass {
 	BlackboxPass() : Pass("blackbox", "change type of cells in the design") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -34,7 +34,7 @@ struct BlackboxPass : public Pass {
 		log("module attribute).\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++)
diff --git a/passes/cmds/check.cc b/passes/cmds/check.cc
index bb8fe6856..64697c134 100644
--- a/passes/cmds/check.cc
+++ b/passes/cmds/check.cc
@@ -27,7 +27,7 @@ PRIVATE_NAMESPACE_BEGIN
 
 struct CheckPass : public Pass {
 	CheckPass() : Pass("check", "check for obvious problems in the design") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -51,7 +51,7 @@ struct CheckPass : public Pass {
 		log("problems are found in the current design.\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
 	{
 		int counter = 0;
 		bool noinit = false;
diff --git a/passes/cmds/chformal.cc b/passes/cmds/chformal.cc
index a8c1fef85..522758eae 100644
--- a/passes/cmds/chformal.cc
+++ b/passes/cmds/chformal.cc
@@ -25,7 +25,7 @@ PRIVATE_NAMESPACE_BEGIN
 
 struct ChformalPass : public Pass {
 	ChformalPass() : Pass("chformal", "change formal constraints of the design") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -62,7 +62,7 @@ struct ChformalPass : public Pass {
 		log("        change the roles of cells as indicated. this options can be combined\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
 	{
 		bool assert2assume = false;
 		bool assume2assert = false;
diff --git a/passes/cmds/chtype.cc b/passes/cmds/chtype.cc
index 90d51667c..979aeadd4 100644
--- a/passes/cmds/chtype.cc
+++ b/passes/cmds/chtype.cc
@@ -24,7 +24,7 @@ PRIVATE_NAMESPACE_BEGIN
 
 struct ChtypePass : public Pass {
 	ChtypePass() : Pass("chtype", "change type of cells in the design") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -40,7 +40,7 @@ struct ChtypePass : public Pass {
 		log("\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
 	{
 		IdString set_type;
 		dict<IdString, IdString> map_types;
diff --git a/passes/cmds/connect.cc b/passes/cmds/connect.cc
index 52611cf44..d480b79ac 100644
--- a/passes/cmds/connect.cc
+++ b/passes/cmds/connect.cc
@@ -43,7 +43,7 @@ static void unset_drivers(RTLIL::Design *design, RTLIL::Module *module, SigMap &
 
 struct ConnectPass : public Pass {
 	ConnectPass() : Pass("connect", "create or remove connections") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -75,7 +75,7 @@ struct ConnectPass : public Pass {
 		log("This command does not operate on module with processes.\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
 	{
 		RTLIL::Module *module = NULL;
 		for (auto &it : design->modules_) {
diff --git a/passes/cmds/connwrappers.cc b/passes/cmds/connwrappers.cc
index 1ea48b7eb..5a15cbbaf 100644
--- a/passes/cmds/connwrappers.cc
+++ b/passes/cmds/connwrappers.cc
@@ -150,7 +150,7 @@ struct ConnwrappersWorker
 
 struct ConnwrappersPass : public Pass {
 	ConnwrappersPass() : Pass("connwrappers", "match width of input-output port pairs") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -172,7 +172,7 @@ struct ConnwrappersPass : public Pass {
 		log("The options -signed, -unsigned, and -port can be specified multiple times.\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
 	{
 		ConnwrappersWorker worker;
 
diff --git a/passes/cmds/copy.cc b/passes/cmds/copy.cc
index fb863512b..acd2dba52 100644
--- a/passes/cmds/copy.cc
+++ b/passes/cmds/copy.cc
@@ -26,7 +26,7 @@ PRIVATE_NAMESPACE_BEGIN
 
 struct CopyPass : public Pass {
 	CopyPass() : Pass("copy", "copy modules in the design") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -36,7 +36,7 @@ struct CopyPass : public Pass {
 		log("by this command.\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() != 3)
 			log_cmd_error("Invalid number of arguments!\n");
diff --git a/passes/cmds/cover.cc b/passes/cmds/cover.cc
index ef4f3f7d0..0ec747671 100644
--- a/passes/cmds/cover.cc
+++ b/passes/cmds/cover.cc
@@ -35,7 +35,7 @@ PRIVATE_NAMESPACE_BEGIN
 
 struct CoverPass : public Pass {
 	CoverPass() : Pass("cover", "print code coverage counters") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -83,7 +83,7 @@ struct CoverPass : public Pass {
 		log("Coverage counters are only available in Yosys for Linux.\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
 	{
 		std::vector<FILE*> out_files;
 		std::vector<std::string> patterns;
diff --git a/passes/cmds/delete.cc b/passes/cmds/delete.cc
index 6d51d30e7..f8d91ea48 100644
--- a/passes/cmds/delete.cc
+++ b/passes/cmds/delete.cc
@@ -24,7 +24,7 @@ PRIVATE_NAMESPACE_BEGIN
 
 struct DeletePass : public Pass {
 	DeletePass() : Pass("delete", "delete objects in the design") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -40,7 +40,7 @@ struct DeletePass : public Pass {
 		log("selected wires, thus 'deleting' module ports.\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
 	{
 		bool flag_input = false;
 		bool flag_output = false;
diff --git a/passes/cmds/design.cc b/passes/cmds/design.cc
index 490c8dde5..172addcc1 100644
--- a/passes/cmds/design.cc
+++ b/passes/cmds/design.cc
@@ -27,7 +27,7 @@ std::vector<RTLIL::Design*> pushed_designs;
 
 struct DesignPass : public Pass {
 	DesignPass() : Pass("design", "save, restore and reset current design") { }
-	virtual ~DesignPass() {
+	~DesignPass() YS_OVERRIDE {
 		for (auto &it : saved_designs)
 			delete it.second;
 		saved_designs.clear();
@@ -35,7 +35,7 @@ struct DesignPass : public Pass {
 			delete it;
 		pushed_designs.clear();
 	}
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -94,7 +94,7 @@ struct DesignPass : public Pass {
 		log("between calls to 'read_verilog'. This command resets this memory.\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
 	{
 		bool got_mode = false;
 		bool reset_mode = false;
diff --git a/passes/cmds/edgetypes.cc b/passes/cmds/edgetypes.cc
index 7b75a009f..58ed6457d 100644
--- a/passes/cmds/edgetypes.cc
+++ b/passes/cmds/edgetypes.cc
@@ -25,7 +25,7 @@ PRIVATE_NAMESPACE_BEGIN
 
 struct EdgetypePass : public Pass {
 	EdgetypePass() : Pass("edgetypes", "list all types of edges in selection") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -35,7 +35,7 @@ struct EdgetypePass : public Pass {
 		log("is a 4-tuple of source and sink cell type and port 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++) {
diff --git a/passes/cmds/logcmd.cc b/passes/cmds/logcmd.cc
index 85386f3d2..522e1089d 100644
--- a/passes/cmds/logcmd.cc
+++ b/passes/cmds/logcmd.cc
@@ -27,7 +27,7 @@ PRIVATE_NAMESPACE_BEGIN
 
 struct LogPass : public Pass {
 	LogPass() : Pass("log", "print text and log files") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -52,7 +52,7 @@ struct LogPass : public Pass {
 		log("        do not append a newline\n");
 		log("\n");
 	}
-	virtual void execute(std::vector<std::string> args, RTLIL::Design*)
+	void execute(std::vector<std::string> args, RTLIL::Design*) YS_OVERRIDE
 	{
 		size_t argidx;
 		bool to_stdout = false;
diff --git a/passes/cmds/ltp.cc b/passes/cmds/ltp.cc
index 42dc794ec..05701710b 100644
--- a/passes/cmds/ltp.cc
+++ b/passes/cmds/ltp.cc
@@ -141,7 +141,7 @@ struct LtpWorker
 
 struct LtpPass : public Pass {
 	LtpPass() : Pass("ltp", "print longest topological path") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -154,7 +154,7 @@ struct LtpPass : public Pass {
 		log("        automatically exclude FF cell types\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
 	{
 		bool noff = false;
 
diff --git a/passes/cmds/plugin.cc b/passes/cmds/plugin.cc
index 828c671de..aa6d5b6cc 100644
--- a/passes/cmds/plugin.cc
+++ b/passes/cmds/plugin.cc
@@ -58,7 +58,7 @@ void load_plugin(std::string, std::vector<std::string>)
 
 struct PluginPass : public Pass {
 	PluginPass() : Pass("plugin", "load and list loaded plugins") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -76,7 +76,7 @@ struct PluginPass : public Pass {
 		log("        List loaded plugins\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
 	{
 		std::string plugin_filename;
 		std::vector<std::string> plugin_aliases;
diff --git a/passes/cmds/qwp.cc b/passes/cmds/qwp.cc
index f2dfa760e..1c64a7b77 100644
--- a/passes/cmds/qwp.cc
+++ b/passes/cmds/qwp.cc
@@ -778,7 +778,7 @@ struct QwpWorker
 
 struct QwpPass : public Pass {
 	QwpPass() : Pass("qwp", "quadratic wirelength placer") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -808,7 +808,7 @@ struct QwpPass : public Pass {
 		log("dense matrix operations. It is only a toy-placer for small circuits.\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
 	{
 		QwpConfig config;
 		xorshift32_state = 123456789;
diff --git a/passes/cmds/rename.cc b/passes/cmds/rename.cc
index 6a002869b..dce576fdf 100644
--- a/passes/cmds/rename.cc
+++ b/passes/cmds/rename.cc
@@ -54,7 +54,7 @@ static void rename_in_module(RTLIL::Module *module, std::string from_name, std::
 
 struct RenamePass : public Pass {
 	RenamePass() : Pass("rename", "rename object in the design") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -81,7 +81,7 @@ struct RenamePass : public Pass {
 		log("Rename top module.\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
 	{
 		std::string pattern_prefix = "_", pattern_suffix = "_";
 		bool flag_enumerate = false;
diff --git a/passes/cmds/scatter.cc b/passes/cmds/scatter.cc
index f083e1f67..7123ba9fb 100644
--- a/passes/cmds/scatter.cc
+++ b/passes/cmds/scatter.cc
@@ -27,7 +27,7 @@ PRIVATE_NAMESPACE_BEGIN
 
 struct ScatterPass : public Pass {
 	ScatterPass() : Pass("scatter", "add additional intermediate nets") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -41,7 +41,7 @@ struct ScatterPass : public Pass {
 		log("Use the opt_clean command to get rid of the additional nets.\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
 	{
 		CellTypes ct(design);
 		extra_args(args, 1, design);
diff --git a/passes/cmds/scc.cc b/passes/cmds/scc.cc
index 76363e051..99f4fbae8 100644
--- a/passes/cmds/scc.cc
+++ b/passes/cmds/scc.cc
@@ -218,7 +218,7 @@ struct SccWorker
 
 struct SccPass : public Pass {
 	SccPass() : Pass("scc", "detect strongly connected components (logic loops)") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -255,7 +255,7 @@ struct SccPass : public Pass {
 		log("        that are part of a found logic loop\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
 	{
 		std::map<std::string, std::string> setAttr;
 		bool allCellTypes = false;
diff --git a/passes/cmds/select.cc b/passes/cmds/select.cc
index a0720797f..d97aa2b37 100644
--- a/passes/cmds/select.cc
+++ b/passes/cmds/select.cc
@@ -950,7 +950,7 @@ PRIVATE_NAMESPACE_BEGIN
 
 struct SelectPass : public Pass {
 	SelectPass() : Pass("select", "modify and view the list of selected objects") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -964,7 +964,7 @@ struct SelectPass : public Pass {
 		log("list of selected objects.\n");
 		log("\n");
 		log("Note that many commands support an optional [selection] argument that can be\n");
-		log("used to override the global selection for the command. The syntax of this\n");
+		log("used to YS_OVERRIDE the global selection for the command. The syntax of this\n");
 		log("optional argument is identical to the syntax of the <selection> argument\n");
 		log("described here.\n");
 		log("\n");
@@ -1167,7 +1167,7 @@ struct SelectPass : public Pass {
 		log("    select */t:SWITCH %%x:+[GATE] */t:SWITCH %%d\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
 	{
 		bool add_mode = false;
 		bool del_mode = false;
@@ -1470,7 +1470,7 @@ struct SelectPass : public Pass {
 
 struct CdPass : public Pass {
 	CdPass() : Pass("cd", "a shortcut for 'select -module <name>'") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -1496,7 +1496,7 @@ struct CdPass : public Pass {
 		log("This is just a shortcut for 'select -clear'.\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() != 1 && args.size() != 2)
 			log_cmd_error("Invalid number of arguments.\n");
@@ -1578,7 +1578,7 @@ static void log_matches(const char *title, Module *module, T list)
 
 struct LsPass : public Pass {
 	LsPass() : Pass("ls", "list modules or objects in modules") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -1589,7 +1589,7 @@ struct LsPass : public Pass {
 		log("When an active module is selected, this prints a list of objects in the module.\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 = 1;
 		extra_args(args, argidx, design);
diff --git a/passes/cmds/setattr.cc b/passes/cmds/setattr.cc
index 689e3148b..d38a6b3da 100644
--- a/passes/cmds/setattr.cc
+++ b/passes/cmds/setattr.cc
@@ -56,7 +56,7 @@ static void do_setunset(dict<RTLIL::IdString, RTLIL::Const> &attrs, const std::v
 
 struct SetattrPass : public Pass {
 	SetattrPass() : Pass("setattr", "set/unset attributes on objects") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -69,7 +69,7 @@ struct SetattrPass : public Pass {
 		log("instead of objects within modules.\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
 	{
 		std::vector<setunset_t> setunset_list;
 		bool flag_mod = false;
@@ -130,7 +130,7 @@ struct SetattrPass : public Pass {
 
 struct SetparamPass : public Pass {
 	SetparamPass() : Pass("setparam", "set/unset parameters on objects") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -142,7 +142,7 @@ struct SetparamPass : public Pass {
 		log("The -type option can be used to change the cell type of the selected cells.\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
 	{
 		vector<setunset_t> setunset_list;
 		string new_cell_type;
@@ -188,7 +188,7 @@ struct SetparamPass : public Pass {
 
 struct ChparamPass : public Pass {
 	ChparamPass() : Pass("chparam", "re-evaluate modules with new parameters") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -203,7 +203,7 @@ struct ChparamPass : public Pass {
 		log("List the available parameters of the selected modules.\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
 	{
 		std::vector<setunset_t> setunset_list;
 		dict<RTLIL::IdString, RTLIL::Const> new_parameters;
diff --git a/passes/cmds/setundef.cc b/passes/cmds/setundef.cc
index 1cd942796..eac1f6236 100644
--- a/passes/cmds/setundef.cc
+++ b/passes/cmds/setundef.cc
@@ -142,7 +142,7 @@ struct SetundefWorker
 
 struct SetundefPass : public Pass {
 	SetundefPass() : Pass("setundef", "replace undef values with defined constants") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -179,7 +179,7 @@ struct SetundefPass : public Pass {
 		log("        also create/update init values for flip-flops\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
 	{
 		bool got_value = false;
 		bool undriven_mode = false;
diff --git a/passes/cmds/show.cc b/passes/cmds/show.cc
index 56e1122bf..ec04418fa 100644
--- a/passes/cmds/show.cc
+++ b/passes/cmds/show.cc
@@ -573,7 +573,7 @@ struct ShowWorker
 
 struct ShowPass : public Pass {
 	ShowPass() : Pass("show", "generate schematics using graphviz") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -655,7 +655,7 @@ struct ShowPass : public Pass {
 		log("the 'show' command is executed.\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
 	{
 		log_header(design, "Generating Graphviz representation of design.\n");
 		log_push();
diff --git a/passes/cmds/splice.cc b/passes/cmds/splice.cc
index 7418ec4d2..bafafca4e 100644
--- a/passes/cmds/splice.cc
+++ b/passes/cmds/splice.cc
@@ -247,7 +247,7 @@ struct SpliceWorker
 
 struct SplicePass : public Pass {
 	SplicePass() : Pass("splice", "create explicit splicing cells") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -288,7 +288,7 @@ struct SplicePass : public Pass {
 		log("by selected wires are rewired.\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
 	{
 		bool sel_by_cell = false;
 		bool sel_by_wire = false;
diff --git a/passes/cmds/splitnets.cc b/passes/cmds/splitnets.cc
index 5e37fc597..f5a1f17b3 100644
--- a/passes/cmds/splitnets.cc
+++ b/passes/cmds/splitnets.cc
@@ -87,7 +87,7 @@ struct SplitnetsWorker
 
 struct SplitnetsPass : public Pass {
 	SplitnetsPass() : Pass("splitnets", "split up multi-bit nets") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -109,7 +109,7 @@ struct SplitnetsPass : public Pass {
 		log("        and split nets so that no driver drives only part of a net.\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
 	{
 		bool flag_ports = false;
 		bool flag_driver = false;
diff --git a/passes/cmds/stat.cc b/passes/cmds/stat.cc
index f1d958a1a..54f4ea817 100644
--- a/passes/cmds/stat.cc
+++ b/passes/cmds/stat.cc
@@ -209,7 +209,7 @@ void read_liberty_cellarea(dict<IdString, double> &cell_area, string liberty_fil
 
 struct StatPass : public Pass {
 	StatPass() : Pass("stat", "print some statistics") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -231,7 +231,7 @@ struct StatPass : public Pass {
 		log("        e.g. $add_8 for an 8 bit wide $add cell.\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
 	{
 		log_header(design, "Printing statistics.\n");
 
diff --git a/passes/cmds/tee.cc b/passes/cmds/tee.cc
index b68c089e9..ff80f3859 100644
--- a/passes/cmds/tee.cc
+++ b/passes/cmds/tee.cc
@@ -27,7 +27,7 @@ PRIVATE_NAMESPACE_BEGIN
 
 struct TeePass : public Pass {
 	TeePass() : Pass("tee", "redirect command output to file") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -49,7 +49,7 @@ struct TeePass : public Pass {
 		log("        Add/subract INT from the -v setting for this command.\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
 	{
 		std::vector<FILE*> backup_log_files, files_to_close;
 		int backup_log_verbose_level = log_verbose_level;
diff --git a/passes/cmds/torder.cc b/passes/cmds/torder.cc
index 56223610d..3c0eac8de 100644
--- a/passes/cmds/torder.cc
+++ b/passes/cmds/torder.cc
@@ -27,7 +27,7 @@ PRIVATE_NAMESPACE_BEGIN
 
 struct TorderPass : public Pass {
 	TorderPass() : Pass("torder", "print cells in topological order") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -43,7 +43,7 @@ struct TorderPass : public Pass {
 		log("        are not used in topological sorting. this option deactivates that.\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
 	{
 		bool noautostop = false;
 		dict<IdString, pool<IdString>> stop_db;
diff --git a/passes/cmds/trace.cc b/passes/cmds/trace.cc
index 1a5f873ff..f5305cde9 100644
--- a/passes/cmds/trace.cc
+++ b/passes/cmds/trace.cc
@@ -25,34 +25,34 @@ PRIVATE_NAMESPACE_BEGIN
 
 struct TraceMonitor : public RTLIL::Monitor
 {
-	virtual void notify_module_add(RTLIL::Module *module) YS_OVERRIDE
+	void notify_module_add(RTLIL::Module *module) YS_OVERRIDE
 	{
 		log("#TRACE# Module add: %s\n", log_id(module));
 	}
 
-	virtual void notify_module_del(RTLIL::Module *module) YS_OVERRIDE
+	void notify_module_del(RTLIL::Module *module) YS_OVERRIDE
 	{
 		log("#TRACE# Module delete: %s\n", log_id(module));
 	}
 
-	virtual void notify_connect(RTLIL::Cell *cell, const RTLIL::IdString &port, const RTLIL::SigSpec &old_sig, RTLIL::SigSpec &sig) YS_OVERRIDE
+	void notify_connect(RTLIL::Cell *cell, const RTLIL::IdString &port, const RTLIL::SigSpec &old_sig, RTLIL::SigSpec &sig) YS_OVERRIDE
 	{
 		log("#TRACE# Cell connect: %s.%s.%s = %s (was: %s)\n", log_id(cell->module), log_id(cell), log_id(port), log_signal(sig), log_signal(old_sig));
 	}
 
-	virtual void notify_connect(RTLIL::Module *module, const RTLIL::SigSig &sigsig) YS_OVERRIDE
+	void notify_connect(RTLIL::Module *module, const RTLIL::SigSig &sigsig) YS_OVERRIDE
 	{
 		log("#TRACE# Connection in module %s: %s = %s\n", log_id(module), log_signal(sigsig.first), log_signal(sigsig.second));
 	}
 
-	virtual void notify_connect(RTLIL::Module *module, const std::vector<RTLIL::SigSig> &sigsig_vec) YS_OVERRIDE
+	void notify_connect(RTLIL::Module *module, const std::vector<RTLIL::SigSig> &sigsig_vec) YS_OVERRIDE
 	{
 		log("#TRACE# New connections in module %s:\n", log_id(module));
 		for (auto &sigsig : sigsig_vec)
 			log("##    %s = %s\n", log_signal(sigsig.first), log_signal(sigsig.second));
 	}
 
-	virtual void notify_blackout(RTLIL::Module *module) YS_OVERRIDE
+	void notify_blackout(RTLIL::Module *module) YS_OVERRIDE
 	{
 		log("#TRACE# Blackout in module %s:\n", log_id(module));
 	}
@@ -60,7 +60,7 @@ struct TraceMonitor : public RTLIL::Monitor
 
 struct TracePass : public Pass {
 	TracePass() : Pass("trace", "redirect command output to file") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -70,7 +70,7 @@ struct TracePass : public Pass {
 		log("the design in real time.\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++)
@@ -95,4 +95,3 @@ struct TracePass : public Pass {
 } TracePass;
 
 PRIVATE_NAMESPACE_END
-
diff --git a/passes/cmds/write_file.cc b/passes/cmds/write_file.cc
index 70892a945..9613b462b 100644
--- a/passes/cmds/write_file.cc
+++ b/passes/cmds/write_file.cc
@@ -25,7 +25,7 @@ PRIVATE_NAMESPACE_BEGIN
 
 struct WriteFileFrontend : public Frontend {
 	WriteFileFrontend() : Frontend("=write_file", "write a text to a file") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -44,7 +44,7 @@ struct WriteFileFrontend : public Frontend {
 		log("    EOT\n");
 		log("\n");
 	}
-	virtual void execute(std::istream *&f, std::string filename, std::vector<std::string> args, RTLIL::Design*)
+	void execute(std::istream *&f, std::string filename, std::vector<std::string> args, RTLIL::Design*) YS_OVERRIDE
 	{
 		bool append_mode = false;
 		std::string output_filename;
diff --git a/passes/equiv/equiv_add.cc b/passes/equiv/equiv_add.cc
index 0494a724f..71599f46e 100644
--- a/passes/equiv/equiv_add.cc
+++ b/passes/equiv/equiv_add.cc
@@ -25,7 +25,7 @@ PRIVATE_NAMESPACE_BEGIN
 
 struct EquivAddPass : public Pass {
 	EquivAddPass() : Pass("equiv_add", "add a $equiv cell") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -39,7 +39,7 @@ struct EquivAddPass : public Pass {
 		log("This command adds $equiv cells for the ports of the specified cells.\n");
 		log("\n");
 	}
-	virtual void execute(std::vector<std::string> args, Design *design)
+	void execute(std::vector<std::string> args, Design *design) YS_OVERRIDE
 	{
 		bool try_mode = false;
 
diff --git a/passes/equiv/equiv_induct.cc b/passes/equiv/equiv_induct.cc
index c958c3de4..bcc68d6d2 100644
--- a/passes/equiv/equiv_induct.cc
+++ b/passes/equiv/equiv_induct.cc
@@ -162,7 +162,7 @@ struct EquivInductWorker
 
 struct EquivInductPass : public Pass {
 	EquivInductPass() : Pass("equiv_induct", "proving $equiv cells using temporal induction") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -192,7 +192,7 @@ struct EquivInductPass : public Pass {
 		log("after reset.\n");
 		log("\n");
 	}
-	virtual void execute(std::vector<std::string> args, Design *design)
+	void execute(std::vector<std::string> args, Design *design) YS_OVERRIDE
 	{
 		int success_counter = 0;
 		bool model_undef = false;
diff --git a/passes/equiv/equiv_make.cc b/passes/equiv/equiv_make.cc
index b20463777..b1f88d55e 100644
--- a/passes/equiv/equiv_make.cc
+++ b/passes/equiv/equiv_make.cc
@@ -390,7 +390,7 @@ struct EquivMakeWorker
 
 struct EquivMakePass : public Pass {
 	EquivMakePass() : Pass("equiv_make", "prepare a circuit for equivalence checking") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -415,7 +415,7 @@ struct EquivMakePass : public Pass {
 		log("checking problem. Use 'miter -equiv' if you want to create a miter circuit.\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
 	{
 		EquivMakeWorker worker;
 		worker.ct.setup(design);
diff --git a/passes/equiv/equiv_mark.cc b/passes/equiv/equiv_mark.cc
index 22c501763..135eaf145 100644
--- a/passes/equiv/equiv_mark.cc
+++ b/passes/equiv/equiv_mark.cc
@@ -204,7 +204,7 @@ struct EquivMarkWorker
 
 struct EquivMarkPass : public Pass {
 	EquivMarkPass() : Pass("equiv_mark", "mark equivalence checking regions") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -216,7 +216,7 @@ struct EquivMarkPass : public Pass {
 		log("wires and cells.\n");
 		log("\n");
 	}
-	virtual void execute(std::vector<std::string> args, Design *design)
+	void execute(std::vector<std::string> args, Design *design) YS_OVERRIDE
 	{
 		log_header(design, "Executing EQUIV_MARK pass.\n");
 
diff --git a/passes/equiv/equiv_miter.cc b/passes/equiv/equiv_miter.cc
index eb2e5a171..e06f9515b 100644
--- a/passes/equiv/equiv_miter.cc
+++ b/passes/equiv/equiv_miter.cc
@@ -261,7 +261,7 @@ struct EquivMiterWorker
 
 struct EquivMiterPass : public Pass {
 	EquivMiterPass() : Pass("equiv_miter", "extract miter from equiv circuit") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -282,7 +282,7 @@ struct EquivMiterPass : public Pass {
 		log("        Create compare logic that handles undefs correctly\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
 	{
 		EquivMiterWorker worker;
 		worker.ct.setup(design);
diff --git a/passes/equiv/equiv_purge.cc b/passes/equiv/equiv_purge.cc
index f8d3cd0af..18b3e7d36 100644
--- a/passes/equiv/equiv_purge.cc
+++ b/passes/equiv/equiv_purge.cc
@@ -176,7 +176,7 @@ struct EquivPurgeWorker
 
 struct EquivPurgePass : public Pass {
 	EquivPurgePass() : Pass("equiv_purge", "purge equivalence checking module") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -187,7 +187,7 @@ struct EquivPurgePass : public Pass {
 		log("ports as needed.\n");
 		log("\n");
 	}
-	virtual void execute(std::vector<std::string> args, Design *design)
+	void execute(std::vector<std::string> args, Design *design) YS_OVERRIDE
 	{
 		log_header(design, "Executing EQUIV_PURGE pass.\n");
 
diff --git a/passes/equiv/equiv_remove.cc b/passes/equiv/equiv_remove.cc
index 770497a51..c5c28c7d9 100644
--- a/passes/equiv/equiv_remove.cc
+++ b/passes/equiv/equiv_remove.cc
@@ -24,7 +24,7 @@ PRIVATE_NAMESPACE_BEGIN
 
 struct EquivRemovePass : public Pass {
 	EquivRemovePass() : Pass("equiv_remove", "remove $equiv cells") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -40,7 +40,7 @@ struct EquivRemovePass : public Pass {
 		log("        keep gate circuit\n");
 		log("\n");
 	}
-	virtual void execute(std::vector<std::string> args, Design *design)
+	void execute(std::vector<std::string> args, Design *design) YS_OVERRIDE
 	{
 		bool mode_gold = false;
 		bool mode_gate = false;
diff --git a/passes/equiv/equiv_simple.cc b/passes/equiv/equiv_simple.cc
index e69e17ac6..c2fab26f2 100644
--- a/passes/equiv/equiv_simple.cc
+++ b/passes/equiv/equiv_simple.cc
@@ -273,7 +273,7 @@ struct EquivSimpleWorker
 
 struct EquivSimplePass : public Pass {
 	EquivSimplePass() : Pass("equiv_simple", "try proving simple $equiv instances") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -298,7 +298,7 @@ struct EquivSimplePass : public Pass {
 		log("        the max. number of time steps to be considered (default = 1)\n");
 		log("\n");
 	}
-	virtual void execute(std::vector<std::string> args, Design *design)
+	void execute(std::vector<std::string> args, Design *design) YS_OVERRIDE
 	{
 		bool verbose = false, short_cones = false, model_undef = false, nogroup = false;
 		int success_counter = 0;
diff --git a/passes/equiv/equiv_status.cc b/passes/equiv/equiv_status.cc
index 7b9230b35..b4a93ccf5 100644
--- a/passes/equiv/equiv_status.cc
+++ b/passes/equiv/equiv_status.cc
@@ -24,7 +24,7 @@ PRIVATE_NAMESPACE_BEGIN
 
 struct EquivStatusPass : public Pass {
 	EquivStatusPass() : Pass("equiv_status", "print status of equivalent checking module") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -36,7 +36,7 @@ struct EquivStatusPass : public Pass {
 		log("        produce an error if any unproven $equiv cell is found\n");
 		log("\n");
 	}
-	virtual void execute(std::vector<std::string> args, Design *design)
+	void execute(std::vector<std::string> args, Design *design) YS_OVERRIDE
 	{
 		bool assert_mode = false;
 		int unproven_count = 0;
diff --git a/passes/equiv/equiv_struct.cc b/passes/equiv/equiv_struct.cc
index c4ced6a71..a7973fd04 100644
--- a/passes/equiv/equiv_struct.cc
+++ b/passes/equiv/equiv_struct.cc
@@ -283,7 +283,7 @@ struct EquivStructWorker
 
 struct EquivStructPass : public Pass {
 	EquivStructPass() : Pass("equiv_struct", "structural equivalence checking") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -314,7 +314,7 @@ struct EquivStructPass : public Pass {
 		log("        maximum number of iterations to run before aborting\n");
 		log("\n");
 	}
-	virtual void execute(std::vector<std::string> args, Design *design)
+	void execute(std::vector<std::string> args, Design *design) YS_OVERRIDE
 	{
 		pool<IdString> fwonly_cells({ "$equiv" });
 		bool mode_icells = false;
diff --git a/passes/fsm/fsm.cc b/passes/fsm/fsm.cc
index 997558b85..c5cb338ab 100644
--- a/passes/fsm/fsm.cc
+++ b/passes/fsm/fsm.cc
@@ -27,7 +27,7 @@ PRIVATE_NAMESPACE_BEGIN
 
 struct FsmPass : public Pass {
 	FsmPass() : Pass("fsm", "extract and optimize finite state machines") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -68,7 +68,7 @@ struct FsmPass : public Pass {
 		log("        passed through to fsm_recode pass\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
 	{
 		bool flag_nomap = false;
 		bool flag_norecode = false;
diff --git a/passes/fsm/fsm_detect.cc b/passes/fsm/fsm_detect.cc
index 9fb5446e7..fc504e98c 100644
--- a/passes/fsm/fsm_detect.cc
+++ b/passes/fsm/fsm_detect.cc
@@ -245,7 +245,7 @@ static void detect_fsm(RTLIL::Wire *wire)
 
 struct FsmDetectPass : public Pass {
 	FsmDetectPass() : Pass("fsm_detect", "finding FSMs in design") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -261,7 +261,7 @@ struct FsmDetectPass : public Pass {
 		log("'fsm_encoding' attribute to \"none\".\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
 	{
 		log_header(design, "Executing FSM_DETECT pass (finding FSMs in design).\n");
 		extra_args(args, 1, design);
diff --git a/passes/fsm/fsm_expand.cc b/passes/fsm/fsm_expand.cc
index 2c344a1c1..c34d0c15c 100644
--- a/passes/fsm/fsm_expand.cc
+++ b/passes/fsm/fsm_expand.cc
@@ -265,7 +265,7 @@ struct FsmExpand
 
 struct FsmExpandPass : public Pass {
 	FsmExpandPass() : Pass("fsm_expand", "expand FSM cells by merging logic into it") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -279,7 +279,7 @@ struct FsmExpandPass : public Pass {
 		log("word-wide cells. Call with -full to consider all cells for merging.\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
 	{
 		bool full_mode = false;
 
diff --git a/passes/fsm/fsm_export.cc b/passes/fsm/fsm_export.cc
index 1cbfcfae8..8eb1872f0 100644
--- a/passes/fsm/fsm_export.cc
+++ b/passes/fsm/fsm_export.cc
@@ -120,7 +120,7 @@ void write_kiss2(struct RTLIL::Module *module, struct RTLIL::Cell *cell, std::st
  */
 struct FsmExportPass : public Pass {
 	FsmExportPass() : Pass("fsm_export", "exporting FSMs to KISS2 files") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -143,7 +143,7 @@ struct FsmExportPass : public Pass {
 		log("        use binary state encoding as state names instead of s0, s1, ...\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
 	{
 		dict<RTLIL::IdString, RTLIL::Const>::iterator attr_it;
 		std::string arg;
diff --git a/passes/fsm/fsm_extract.cc b/passes/fsm/fsm_extract.cc
index 8a4ee3f26..67551f673 100644
--- a/passes/fsm/fsm_extract.cc
+++ b/passes/fsm/fsm_extract.cc
@@ -401,7 +401,7 @@ static void extract_fsm(RTLIL::Wire *wire)
 
 struct FsmExtractPass : public Pass {
 	FsmExtractPass() : Pass("fsm_extract", "extracting FSMs in design") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -417,7 +417,7 @@ struct FsmExtractPass : public Pass {
 		log("'opt_clean' pass to eliminate this signal.\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
 	{
 		log_header(design, "Executing FSM_EXTRACT pass (extracting FSM from design).\n");
 		extra_args(args, 1, design);
diff --git a/passes/fsm/fsm_info.cc b/passes/fsm/fsm_info.cc
index 2cc1a7d53..0548259ee 100644
--- a/passes/fsm/fsm_info.cc
+++ b/passes/fsm/fsm_info.cc
@@ -30,7 +30,7 @@ PRIVATE_NAMESPACE_BEGIN
 
 struct FsmInfoPass : public Pass {
 	FsmInfoPass() : Pass("fsm_info", "print information on finite state machines") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -41,7 +41,7 @@ struct FsmInfoPass : public Pass {
 		log("pass so that this information is included in the synthesis log file.\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
 	{
 		log_header(design, "Executing FSM_INFO pass (dumping all available information on FSM cells).\n");
 		extra_args(args, 1, design);
diff --git a/passes/fsm/fsm_map.cc b/passes/fsm/fsm_map.cc
index 3edaf84d2..90c958912 100644
--- a/passes/fsm/fsm_map.cc
+++ b/passes/fsm/fsm_map.cc
@@ -322,7 +322,7 @@ static void map_fsm(RTLIL::Cell *fsm_cell, RTLIL::Module *module)
 
 struct FsmMapPass : public Pass {
 	FsmMapPass() : Pass("fsm_map", "mapping FSMs to basic logic") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -331,7 +331,7 @@ struct FsmMapPass : public Pass {
 		log("This pass translates FSM cells to flip-flops and logic.\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
 	{
 		log_header(design, "Executing FSM_MAP pass (mapping FSMs to basic logic).\n");
 		extra_args(args, 1, design);
diff --git a/passes/fsm/fsm_opt.cc b/passes/fsm/fsm_opt.cc
index 5b1da44fc..3a6ac2746 100644
--- a/passes/fsm/fsm_opt.cc
+++ b/passes/fsm/fsm_opt.cc
@@ -323,7 +323,7 @@ PRIVATE_NAMESPACE_BEGIN
 
 struct FsmOptPass : public Pass {
 	FsmOptPass() : Pass("fsm_opt", "optimize finite state machines") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -334,7 +334,7 @@ struct FsmOptPass : public Pass {
 		log("combination with the 'opt_clean' pass (see also 'help fsm').\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
 	{
 		log_header(design, "Executing FSM_OPT pass (simple optimizations of FSMs).\n");
 		extra_args(args, 1, design);
diff --git a/passes/fsm/fsm_recode.cc b/passes/fsm/fsm_recode.cc
index e1bde728f..fa1ff48cc 100644
--- a/passes/fsm/fsm_recode.cc
+++ b/passes/fsm/fsm_recode.cc
@@ -126,7 +126,7 @@ static void fsm_recode(RTLIL::Cell *cell, RTLIL::Module *module, FILE *fm_set_fs
 
 struct FsmRecodePass : public Pass {
 	FsmRecodePass() : Pass("fsm_recode", "recoding finite state machines") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -151,7 +151,7 @@ struct FsmRecodePass : public Pass {
 		log("            .map <old_bitpattern> <new_bitpattern>\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
 	{
 		FILE *fm_set_fsm_file = NULL;
 		FILE *encfile = NULL;
diff --git a/passes/hierarchy/hierarchy.cc b/passes/hierarchy/hierarchy.cc
index e61851481..5df69848e 100644
--- a/passes/hierarchy/hierarchy.cc
+++ b/passes/hierarchy/hierarchy.cc
@@ -343,7 +343,7 @@ int find_top_mod_score(Design *design, Module *module, dict<Module*, int> &db)
 
 struct HierarchyPass : public Pass {
 	HierarchyPass() : Pass("hierarchy", "check, expand and clean up design hierarchy") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -414,7 +414,7 @@ struct HierarchyPass : public Pass {
 		log("in the current design.\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
 	{
 		log_header(design, "Executing HIERARCHY pass (managing design hierarchy).\n");
 
diff --git a/passes/hierarchy/submod.cc b/passes/hierarchy/submod.cc
index e9ee4eef9..ec242aa1f 100644
--- a/passes/hierarchy/submod.cc
+++ b/passes/hierarchy/submod.cc
@@ -269,7 +269,7 @@ struct SubmodWorker
 
 struct SubmodPass : public Pass {
 	SubmodPass() : Pass("submod", "moving part of a module to a new submodule") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -297,7 +297,7 @@ struct SubmodPass : public Pass {
 		log("with -copy to not modify the source module.\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
 	{
 		log_header(design, "Executing SUBMOD pass (moving cells to submodules as requested).\n");
 		log_push();
diff --git a/passes/hierarchy/uniquify.cc b/passes/hierarchy/uniquify.cc
index 1da0870f6..c88ecd82e 100644
--- a/passes/hierarchy/uniquify.cc
+++ b/passes/hierarchy/uniquify.cc
@@ -24,7 +24,7 @@ PRIVATE_NAMESPACE_BEGIN
 
 struct UniquifyPass : public Pass {
 	UniquifyPass() : Pass("uniquify", "create unique copies of modules") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -41,7 +41,7 @@ struct UniquifyPass : public Pass {
 		log("attribute set (the 'top' module is unique implicitly).\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
 	{
 		log_header(design, "Executing UNIQUIFY pass (creating unique copies of modules).\n");
 
diff --git a/passes/memory/memory.cc b/passes/memory/memory.cc
index 947d598be..712bc2537 100644
--- a/passes/memory/memory.cc
+++ b/passes/memory/memory.cc
@@ -27,7 +27,7 @@ PRIVATE_NAMESPACE_BEGIN
 
 struct MemoryPass : public Pass {
 	MemoryPass() : Pass("memory", "translate memories to basic cells") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -48,7 +48,7 @@ struct MemoryPass : public Pass {
 		log("or multiport memory blocks if called with the -nomap option.\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
 	{
 		bool flag_nomap = false;
 		bool flag_nordff = false;
diff --git a/passes/memory/memory_bram.cc b/passes/memory/memory_bram.cc
index a7f9cf382..e8552bbcf 100644
--- a/passes/memory/memory_bram.cc
+++ b/passes/memory/memory_bram.cc
@@ -1120,7 +1120,7 @@ void handle_cell(Cell *cell, const rules_t &rules)
 
 struct MemoryBramPass : public Pass {
 	MemoryBramPass() : Pass("memory_bram", "map memories to block rams") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -1210,7 +1210,7 @@ struct MemoryBramPass : public Pass {
 		log("the data bits to accommodate the enable pattern of port A.\n");
 		log("\n");
 	}
-	virtual void execute(vector<string> args, Design *design)
+	void execute(vector<string> args, Design *design) YS_OVERRIDE
 	{
 		rules_t rules;
 
diff --git a/passes/memory/memory_collect.cc b/passes/memory/memory_collect.cc
index ab66e3fb8..70d98713c 100644
--- a/passes/memory/memory_collect.cc
+++ b/passes/memory/memory_collect.cc
@@ -246,7 +246,7 @@ static void handle_module(Design *design, Module *module)
 
 struct MemoryCollectPass : public Pass {
 	MemoryCollectPass() : Pass("memory_collect", "creating multi-port memory cells") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -256,7 +256,7 @@ struct MemoryCollectPass : public Pass {
 		log("memory cells.\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 {
 		log_header(design, "Executing MEMORY_COLLECT pass (generating $mem cells).\n");
 		extra_args(args, 1, design);
 		for (auto &mod_it : design->modules_)
diff --git a/passes/memory/memory_dff.cc b/passes/memory/memory_dff.cc
index 6e036397d..32df19174 100644
--- a/passes/memory/memory_dff.cc
+++ b/passes/memory/memory_dff.cc
@@ -283,7 +283,7 @@ struct MemoryDffWorker
 
 struct MemoryDffPass : public Pass {
 	MemoryDffPass() : Pass("memory_dff", "merge input/output DFFs into memories") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -297,7 +297,7 @@ struct MemoryDffPass : public Pass {
 		log("        do not merge registers on read ports\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
 	{
 		bool flag_wr_only = false;
 
diff --git a/passes/memory/memory_map.cc b/passes/memory/memory_map.cc
index bffeec857..a0b808e56 100644
--- a/passes/memory/memory_map.cc
+++ b/passes/memory/memory_map.cc
@@ -352,7 +352,7 @@ struct MemoryMapWorker
 
 struct MemoryMapPass : public Pass {
 	MemoryMapPass() : Pass("memory_map", "translate multiport memories to basic cells") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -362,7 +362,7 @@ struct MemoryMapPass : public Pass {
 		log("pass to word-wide DFFs and address decoders.\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 {
 		log_header(design, "Executing MEMORY_MAP pass (converting $mem cells to logic and flip-flops).\n");
 		extra_args(args, 1, design);
 		for (auto mod : design->selected_modules())
diff --git a/passes/memory/memory_memx.cc b/passes/memory/memory_memx.cc
index 2b02e2490..958370164 100644
--- a/passes/memory/memory_memx.cc
+++ b/passes/memory/memory_memx.cc
@@ -28,7 +28,7 @@ PRIVATE_NAMESPACE_BEGIN
 
 struct MemoryMemxPass : public Pass {
 	MemoryMemxPass() : Pass("memory_memx", "emulate vlog sim behavior for mem ports") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -38,7 +38,7 @@ struct MemoryMemxPass : public Pass {
 		log("behavior for out-of-bounds memory reads and writes.\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 {
 		log_header(design, "Executing MEMORY_MEMX pass (converting $mem cells to logic and flip-flops).\n");
 		extra_args(args, 1, design);
 
diff --git a/passes/memory/memory_nordff.cc b/passes/memory/memory_nordff.cc
index 87ab7c623..ba0361c0f 100644
--- a/passes/memory/memory_nordff.cc
+++ b/passes/memory/memory_nordff.cc
@@ -25,7 +25,7 @@ PRIVATE_NAMESPACE_BEGIN
 
 struct MemoryNordffPass : public Pass {
 	MemoryNordffPass() : Pass("memory_nordff", "extract read port FFs from memories") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -35,7 +35,7 @@ struct MemoryNordffPass : public Pass {
 		log("similar to what one would get from calling memory_dff with -nordff.\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
 	{
 		log_header(design, "Executing MEMORY_NORDFF pass (extracting $dff cells from $mem).\n");
 
diff --git a/passes/memory/memory_share.cc b/passes/memory/memory_share.cc
index ca09ac52c..172afe0cb 100644
--- a/passes/memory/memory_share.cc
+++ b/passes/memory/memory_share.cc
@@ -726,7 +726,7 @@ struct MemoryShareWorker
 
 struct MemorySharePass : public Pass {
 	MemorySharePass() : Pass("memory_share", "consolidate memory ports") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -752,7 +752,7 @@ struct MemorySharePass : public Pass {
 		log("optimizations) such as \"share\" and \"opt_merge\".\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 {
 		log_header(design, "Executing MEMORY_SHARE pass (consolidating $memrd/$memwr cells).\n");
 		extra_args(args, 1, design);
 		for (auto module : design->selected_modules())
diff --git a/passes/memory/memory_unpack.cc b/passes/memory/memory_unpack.cc
index a0fc31b5e..49ec66792 100644
--- a/passes/memory/memory_unpack.cc
+++ b/passes/memory/memory_unpack.cc
@@ -127,7 +127,7 @@ void handle_module(RTLIL::Design *design, RTLIL::Module *module)
 
 struct MemoryUnpackPass : public Pass {
 	MemoryUnpackPass() : Pass("memory_unpack", "unpack multi-port memory cells") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -137,7 +137,7 @@ struct MemoryUnpackPass : public Pass {
 		log("$memwr cells. It is the counterpart to the memory_collect pass.\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 {
 		log_header(design, "Executing MEMORY_UNPACK pass (generating $memrd/$memwr cells form $mem cells).\n");
 		extra_args(args, 1, design);
 		for (auto &mod_it : design->modules_)
diff --git a/passes/opt/opt.cc b/passes/opt/opt.cc
index 021c1a03f..a4aca2fee 100644
--- a/passes/opt/opt.cc
+++ b/passes/opt/opt.cc
@@ -27,7 +27,7 @@ PRIVATE_NAMESPACE_BEGIN
 
 struct OptPass : public Pass {
 	OptPass() : Pass("opt", "perform simple optimizations") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -63,7 +63,7 @@ struct OptPass : public Pass {
 		log("\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
 	{
 		std::string opt_clean_args;
 		std::string opt_expr_args;
diff --git a/passes/opt/opt_clean.cc b/passes/opt/opt_clean.cc
index 25d462ada..c3b13acaf 100644
--- a/passes/opt/opt_clean.cc
+++ b/passes/opt/opt_clean.cc
@@ -442,7 +442,7 @@ void rmunused_module(RTLIL::Module *module, bool purge_mode, bool verbose, bool
 
 struct OptCleanPass : public Pass {
 	OptCleanPass() : Pass("opt_clean", "remove unused cells and wires") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -459,7 +459,7 @@ struct OptCleanPass : public Pass {
 		log("        also remove internal nets if they have a public 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
 	{
 		bool purge_mode = false;
 
@@ -505,7 +505,7 @@ struct OptCleanPass : public Pass {
 
 struct CleanPass : public Pass {
 	CleanPass() : Pass("clean", "remove unused cells and wires") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -520,7 +520,7 @@ struct CleanPass : public Pass {
 		log("in -purge mode between the commands.\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
 	{
 		bool purge_mode = false;
 
diff --git a/passes/opt/opt_demorgan.cc b/passes/opt/opt_demorgan.cc
index f2af1cb93..1699a6454 100644
--- a/passes/opt/opt_demorgan.cc
+++ b/passes/opt/opt_demorgan.cc
@@ -169,7 +169,7 @@ void demorgan_worker(
 
 struct OptDemorganPass : public Pass {
 	OptDemorganPass() : Pass("opt_demorgan", "Optimize reductions with DeMorgan equivalents") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -179,7 +179,7 @@ struct OptDemorganPass : public Pass {
 		log("overall gate count of the circuit\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
 	{
 		log_header(design, "Executing OPT_DEMORGAN pass (push inverters through $reduce_* cells).\n");
 
diff --git a/passes/opt/opt_expr.cc b/passes/opt/opt_expr.cc
index a54a5c6b8..0ba233c62 100644
--- a/passes/opt/opt_expr.cc
+++ b/passes/opt/opt_expr.cc
@@ -1470,7 +1470,7 @@ void replace_const_cells(RTLIL::Design *design, RTLIL::Module *module, bool cons
 
 struct OptExprPass : public Pass {
 	OptExprPass() : Pass("opt_expr", "perform const folding and simple expression rewriting") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -1504,7 +1504,7 @@ struct OptExprPass : public Pass {
 		log("        replaced by 'a'. the -keepdc option disables all such optimizations.\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
 	{
 		bool mux_undef = false;
 		bool mux_bool = false;
diff --git a/passes/opt/opt_merge.cc b/passes/opt/opt_merge.cc
index 2aeb514e4..eedf88904 100644
--- a/passes/opt/opt_merge.cc
+++ b/passes/opt/opt_merge.cc
@@ -341,7 +341,7 @@ struct OptMergeWorker
 
 struct OptMergePass : public Pass {
 	OptMergePass() : Pass("opt_merge", "consolidate identical cells") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -357,7 +357,7 @@ struct OptMergePass : public Pass {
 		log("        Operate on all cell types, not just built-in types.\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
 	{
 		log_header(design, "Executing OPT_MERGE pass (detect identical cells).\n");
 
diff --git a/passes/opt/opt_muxtree.cc b/passes/opt/opt_muxtree.cc
index f5ddc2af9..87c7ce9b2 100644
--- a/passes/opt/opt_muxtree.cc
+++ b/passes/opt/opt_muxtree.cc
@@ -449,7 +449,7 @@ struct OptMuxtreeWorker
 
 struct OptMuxtreePass : public Pass {
 	OptMuxtreePass() : Pass("opt_muxtree", "eliminate dead trees in multiplexer trees") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -462,7 +462,7 @@ struct OptMuxtreePass : public Pass {
 		log("This pass only operates on completely selected modules without processes.\n");
 		log("\n");
 	}
-	virtual void execute(vector<std::string> args, RTLIL::Design *design)
+	void execute(vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
 	{
 		log_header(design, "Executing OPT_MUXTREE pass (detect dead branches in mux trees).\n");
 		extra_args(args, 1, design);
diff --git a/passes/opt/opt_reduce.cc b/passes/opt/opt_reduce.cc
index eb9d02ad5..d99f1ca6a 100644
--- a/passes/opt/opt_reduce.cc
+++ b/passes/opt/opt_reduce.cc
@@ -329,7 +329,7 @@ struct OptReduceWorker
 
 struct OptReducePass : public Pass {
 	OptReducePass() : Pass("opt_reduce", "simplify large MUXes and AND/OR gates") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -350,7 +350,7 @@ struct OptReducePass : public Pass {
 		log("      alias for -fine\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
 	{
 		bool do_fine = false;
 
diff --git a/passes/opt/opt_rmdff.cc b/passes/opt/opt_rmdff.cc
index b5edb357b..5880254c1 100644
--- a/passes/opt/opt_rmdff.cc
+++ b/passes/opt/opt_rmdff.cc
@@ -399,7 +399,7 @@ delete_dff:
 
 struct OptRmdffPass : public Pass {
 	OptRmdffPass() : Pass("opt_rmdff", "remove DFFs with constant inputs") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -409,7 +409,7 @@ struct OptRmdffPass : public Pass {
 		log("a constant driver.\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
 	{
 		int total_count = 0, total_initdrv = 0;
 		log_header(design, "Executing OPT_RMDFF pass (remove dff with constant values).\n");
diff --git a/passes/opt/rmports.cc b/passes/opt/rmports.cc
index 756be7473..fc1596ebf 100644
--- a/passes/opt/rmports.cc
+++ b/passes/opt/rmports.cc
@@ -28,7 +28,7 @@ PRIVATE_NAMESPACE_BEGIN
 
 struct RmportsPassPass : public Pass {
 	RmportsPassPass() : Pass("rmports", "remove module ports with no connections") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -39,7 +39,7 @@ struct RmportsPassPass : public Pass {
 		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
 	{
 		log_header(design, "Executing RMPORTS pass (remove ports with no connections).\n");
 
diff --git a/passes/opt/share.cc b/passes/opt/share.cc
index 22914eaa7..b80280829 100644
--- a/passes/opt/share.cc
+++ b/passes/opt/share.cc
@@ -1421,7 +1421,7 @@ struct ShareWorker
 
 struct SharePass : public Pass {
 	SharePass() : Pass("share", "perform sat-based resource sharing") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -1453,7 +1453,7 @@ struct SharePass : public Pass {
 		log("    Only perform the first N merges, then stop. This is useful for debugging.\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
 	{
 		ShareWorkerConfig config;
 
diff --git a/passes/opt/wreduce.cc b/passes/opt/wreduce.cc
index 07503fbb3..0164f58d6 100644
--- a/passes/opt/wreduce.cc
+++ b/passes/opt/wreduce.cc
@@ -353,7 +353,7 @@ struct WreduceWorker
 
 struct WreducePass : public Pass {
 	WreducePass() : Pass("wreduce", "reduce the word size of operations if possible") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -373,7 +373,7 @@ struct WreducePass : public Pass {
 		log("        flows that use the 'memory_memx' pass.\n");
 		log("\n");
 	}
-	virtual void execute(std::vector<std::string> args, Design *design)
+	void execute(std::vector<std::string> args, Design *design) YS_OVERRIDE
 	{
 		WreduceConfig config;
 		bool opt_memx = false;
diff --git a/passes/proc/proc.cc b/passes/proc/proc.cc
index d5366f266..ef7cb0f71 100644
--- a/passes/proc/proc.cc
+++ b/passes/proc/proc.cc
@@ -27,7 +27,7 @@ PRIVATE_NAMESPACE_BEGIN
 
 struct ProcPass : public Pass {
 	ProcPass() : Pass("proc", "translate processes to netlists") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -57,7 +57,7 @@ struct ProcPass : public Pass {
 		log("        executed in -ifx mode.\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
 	{
 		std::string global_arst;
 		bool ifxmode = false;
diff --git a/passes/proc/proc_arst.cc b/passes/proc/proc_arst.cc
index 216b00ddd..b69eba3f9 100644
--- a/passes/proc/proc_arst.cc
+++ b/passes/proc/proc_arst.cc
@@ -203,7 +203,7 @@ restart_proc_arst:
 
 struct ProcArstPass : public Pass {
 	ProcArstPass() : Pass("proc_arst", "detect asynchronous resets") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -221,7 +221,7 @@ struct ProcArstPass : public Pass {
 		log("        in the 'init' attribute on the net.\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
 	{
 		std::string global_arst;
 		bool global_arst_neg = false;
diff --git a/passes/proc/proc_clean.cc b/passes/proc/proc_clean.cc
index 7dbabc211..b9e43d1db 100644
--- a/passes/proc/proc_clean.cc
+++ b/passes/proc/proc_clean.cc
@@ -143,7 +143,7 @@ void proc_clean(RTLIL::Module *mod, RTLIL::Process *proc, int &total_count)
 
 struct ProcCleanPass : public Pass {
 	ProcCleanPass() : Pass("proc_clean", "remove empty parts of processes") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -153,7 +153,7 @@ struct ProcCleanPass : public Pass {
 		log("if it contains only empty structures.\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
 	{
 		int total_count = 0;
 		log_header(design, "Executing PROC_CLEAN pass (remove empty switches from decision trees).\n");
diff --git a/passes/proc/proc_dff.cc b/passes/proc/proc_dff.cc
index f732baa17..519d35cd6 100644
--- a/passes/proc/proc_dff.cc
+++ b/passes/proc/proc_dff.cc
@@ -370,7 +370,7 @@ void proc_dff(RTLIL::Module *mod, RTLIL::Process *proc, ConstEval &ce)
 
 struct ProcDffPass : public Pass {
 	ProcDffPass() : Pass("proc_dff", "extract flip-flops from processes") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -380,7 +380,7 @@ struct ProcDffPass : public Pass {
 		log("d-type flip-flop cells.\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
 	{
 		log_header(design, "Executing PROC_DFF pass (convert process syncs to FFs).\n");
 
diff --git a/passes/proc/proc_dlatch.cc b/passes/proc/proc_dlatch.cc
index 15200ec12..d9d5dfbed 100644
--- a/passes/proc/proc_dlatch.cc
+++ b/passes/proc/proc_dlatch.cc
@@ -422,7 +422,7 @@ void proc_dlatch(proc_dlatch_db_t &db, RTLIL::Process *proc)
 
 struct ProcDlatchPass : public Pass {
 	ProcDlatchPass() : Pass("proc_dlatch", "extract latches from processes") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -432,7 +432,7 @@ struct ProcDlatchPass : public Pass {
 		log("d-type latches.\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
 	{
 		log_header(design, "Executing PROC_DLATCH pass (convert process syncs to latches).\n");
 
diff --git a/passes/proc/proc_init.cc b/passes/proc/proc_init.cc
index 0c8fb83dc..e2dc07e53 100644
--- a/passes/proc/proc_init.cc
+++ b/passes/proc/proc_init.cc
@@ -102,7 +102,7 @@ void proc_init(RTLIL::Module *mod, RTLIL::Process *proc)
 
 struct ProcInitPass : public Pass {
 	ProcInitPass() : Pass("proc_init", "convert initial block to init attributes") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -113,7 +113,7 @@ struct ProcInitPass : public Pass {
 		log("respective wire.\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
 	{
 		log_header(design, "Executing PROC_INIT pass (extract init attributes).\n");
 
diff --git a/passes/proc/proc_mux.cc b/passes/proc/proc_mux.cc
index 57e131ca5..1329c1fef 100644
--- a/passes/proc/proc_mux.cc
+++ b/passes/proc/proc_mux.cc
@@ -382,7 +382,7 @@ void proc_mux(RTLIL::Module *mod, RTLIL::Process *proc, bool ifxmode)
 
 struct ProcMuxPass : public Pass {
 	ProcMuxPass() : Pass("proc_mux", "convert decision trees to multiplexers") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -396,7 +396,7 @@ struct ProcMuxPass : public Pass {
 		log("        'case' expressions and 'if' conditions.\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
 	{
 		bool ifxmode = false;
 		log_header(design, "Executing PROC_MUX pass (convert decision trees to multiplexers).\n");
diff --git a/passes/proc/proc_rmdead.cc b/passes/proc/proc_rmdead.cc
index 5672fb475..7c334e661 100644
--- a/passes/proc/proc_rmdead.cc
+++ b/passes/proc/proc_rmdead.cc
@@ -65,7 +65,7 @@ void proc_rmdead(RTLIL::SwitchRule *sw, int &counter)
 
 struct ProcRmdeadPass : public Pass {
 	ProcRmdeadPass() : Pass("proc_rmdead", "eliminate dead trees in decision trees") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -74,7 +74,7 @@ struct ProcRmdeadPass : public Pass {
 		log("This pass identifies unreachable branches in decision trees and removes them.\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
 	{
 		log_header(design, "Executing PROC_RMDEAD pass (remove dead branches from decision trees).\n");
 
diff --git a/passes/sat/Makefile.inc b/passes/sat/Makefile.inc
index 4fcce2fad..8ab0280c0 100644
--- a/passes/sat/Makefile.inc
+++ b/passes/sat/Makefile.inc
@@ -7,4 +7,5 @@ OBJS += passes/sat/miter.o
 OBJS += passes/sat/expose.o
 OBJS += passes/sat/assertpmux.o
 OBJS += passes/sat/clk2fflogic.o
+OBJS += passes/sat/async2sync.o
 
diff --git a/passes/sat/assertpmux.cc b/passes/sat/assertpmux.cc
index 63a907671..509cb0ba9 100644
--- a/passes/sat/assertpmux.cc
+++ b/passes/sat/assertpmux.cc
@@ -181,7 +181,7 @@ struct AssertpmuxWorker
 
 struct AssertpmuxPass : public Pass {
 	AssertpmuxPass() : Pass("assertpmux", "convert internal signals to module ports") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -199,7 +199,7 @@ struct AssertpmuxPass : public Pass {
 		log("        additional constrained and check the $pmux condition always.\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
 	{
 		bool flag_noinit = false;
 		bool flag_always = false;
diff --git a/passes/sat/async2sync.cc b/passes/sat/async2sync.cc
new file mode 100644
index 000000000..c92db7118
--- /dev/null
+++ b/passes/sat/async2sync.cc
@@ -0,0 +1,147 @@
+/*
+ *  yosys -- Yosys Open SYnthesis Suite
+ *
+ *  Copyright (C) 2012  Clifford Wolf <clifford@clifford.at>
+ *
+ *  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.
+ *
+ */
+
+#include "kernel/yosys.h"
+#include "kernel/sigtools.h"
+
+USING_YOSYS_NAMESPACE
+PRIVATE_NAMESPACE_BEGIN
+
+struct Async2syncPass : public Pass {
+	Async2syncPass() : Pass("async2sync", "convert async FF inputs to sync circuits") { }
+	void help() YS_OVERRIDE
+	{
+		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
+		log("\n");
+		log("    async2sync [options] [selection]\n");
+		log("\n");
+		log("This command replaces async FF inputs with sync circuits emulating the same\n");
+		log("behavior for when the async signals are actually synchronized to the clock.\n");
+		log("\n");
+		log("This pass assumes negative hold time for the async FF inputs. For example when\n");
+		log("a reset deasserts with the clock edge, then the FF output will still drive the\n");
+		log("reset value in the next cycle regardless of the data-in value at the time of\n");
+		log("the clock edge.\n");
+		log("\n");
+		log("Currently only $adff cells are supported by this pass.\n");
+		log("\n");
+	}
+	void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
+	{
+		// bool flag_noinit = false;
+
+		log_header(design, "Executing ASYNC2SYNC pass.\n");
+
+		size_t argidx;
+		for (argidx = 1; argidx < args.size(); argidx++)
+		{
+			// if (args[argidx] == "-noinit") {
+			// 	flag_noinit = true;
+			// 	continue;
+			// }
+			break;
+		}
+		extra_args(args, argidx, design);
+
+		for (auto module : design->selected_modules())
+		{
+			SigMap sigmap(module);
+			dict<SigBit, State> initbits;
+			pool<SigBit> del_initbits;
+
+			for (auto wire : module->wires())
+				if (wire->attributes.count("\\init") > 0)
+				{
+					Const initval = wire->attributes.at("\\init");
+					SigSpec initsig = sigmap(wire);
+
+					for (int i = 0; i < GetSize(initval) && i < GetSize(initsig); i++)
+						if (initval[i] == State::S0 || initval[i] == State::S1)
+							initbits[initsig[i]] = initval[i];
+				}
+
+			for (auto cell : vector<Cell*>(module->selected_cells()))
+			{
+				if (cell->type.in("$adff"))
+				{
+					// bool clk_pol = cell->parameters["\\CLK_POLARITY"].as_bool();
+					bool arst_pol = cell->parameters["\\ARST_POLARITY"].as_bool();
+					Const arst_val = cell->parameters["\\ARST_VALUE"];
+
+					SigSpec sig_clk = cell->getPort("\\CLK");
+					SigSpec sig_arst = cell->getPort("\\ARST");
+					SigSpec sig_d = cell->getPort("\\D");
+					SigSpec sig_q = cell->getPort("\\Q");
+
+					log("Replacing %s.%s (%s): ARST=%s, D=%s, Q=%s\n",
+							log_id(module), log_id(cell), log_id(cell->type),
+							log_signal(sig_arst), log_signal(sig_d), log_signal(sig_q));
+
+					Const init_val;
+					for (int i = 0; i < GetSize(sig_q); i++) {
+						SigBit bit = sigmap(sig_q[i]);
+						init_val.bits.push_back(initbits.count(bit) ? initbits.at(bit) : State::Sx);
+						del_initbits.insert(bit);
+					}
+
+					Wire *new_d = module->addWire(NEW_ID, GetSize(sig_d));
+					Wire *new_q = module->addWire(NEW_ID, GetSize(sig_q));
+					new_q->attributes["\\init"] = init_val;
+
+					if (arst_pol) {
+						module->addMux(NEW_ID, sig_d, arst_val, sig_arst, new_d);
+						module->addMux(NEW_ID, new_q, arst_val, sig_arst, sig_q);
+					} else {
+						module->addMux(NEW_ID, arst_val, sig_d, sig_arst, new_d);
+						module->addMux(NEW_ID, arst_val, new_q, sig_arst, sig_q);
+					}
+
+					cell->setPort("\\D", new_d);
+					cell->setPort("\\Q", new_q);
+					cell->unsetPort("\\ARST");
+					cell->unsetParam("\\ARST_POLARITY");
+					cell->unsetParam("\\ARST_VALUE");
+					cell->type = "$dff";
+					continue;
+				}
+			}
+
+			for (auto wire : module->wires())
+				if (wire->attributes.count("\\init") > 0)
+				{
+					bool delete_initattr = true;
+					Const initval = wire->attributes.at("\\init");
+					SigSpec initsig = sigmap(wire);
+
+					for (int i = 0; i < GetSize(initval) && i < GetSize(initsig); i++)
+						if (del_initbits.count(initsig[i]) > 0)
+							initval[i] = State::Sx;
+						else if (initval[i] != State::Sx)
+							delete_initattr = false;
+
+					if (delete_initattr)
+						wire->attributes.erase("\\init");
+					else
+						wire->attributes.at("\\init") = initval;
+				}
+		}
+	}
+} Async2syncPass;
+
+PRIVATE_NAMESPACE_END
diff --git a/passes/sat/clk2fflogic.cc b/passes/sat/clk2fflogic.cc
index 736c6f571..49ec795d3 100644
--- a/passes/sat/clk2fflogic.cc
+++ b/passes/sat/clk2fflogic.cc
@@ -25,7 +25,7 @@ PRIVATE_NAMESPACE_BEGIN
 
 struct Clk2fflogicPass : public Pass {
 	Clk2fflogicPass() : Pass("clk2fflogic", "convert clocked FFs to generic $ff cells") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -36,7 +36,7 @@ struct Clk2fflogicPass : public Pass {
 		log("multiple clocks.\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
 	{
 		// bool flag_noinit = false;
 
diff --git a/passes/sat/eval.cc b/passes/sat/eval.cc
index 09f69cc5c..008cd2dfa 100644
--- a/passes/sat/eval.cc
+++ b/passes/sat/eval.cc
@@ -360,7 +360,7 @@ struct VlogHammerReporter
 
 struct EvalPass : public Pass {
 	EvalPass() : Pass("eval", "evaluate the circuit given an input") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -383,7 +383,7 @@ struct EvalPass : public Pass {
 		log("        then all output ports of the current module are used.\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
 	{
 		std::vector<std::pair<std::string, std::string>> sets;
 		std::vector<std::string> shows, tables;
diff --git a/passes/sat/expose.cc b/passes/sat/expose.cc
index fa8f0c6be..809345486 100644
--- a/passes/sat/expose.cc
+++ b/passes/sat/expose.cc
@@ -220,7 +220,7 @@ RTLIL::Wire *add_new_wire(RTLIL::Module *module, RTLIL::IdString name, int width
 
 struct ExposePass : public Pass {
 	ExposePass() : Pass("expose", "convert internal signals to module ports") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -257,7 +257,7 @@ struct ExposePass : public Pass {
 		log("        designator for the exposed signal.\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
 	{
 		bool flag_shared = false;
 		bool flag_evert = false;
diff --git a/passes/sat/freduce.cc b/passes/sat/freduce.cc
index a3028bfce..f29631639 100644
--- a/passes/sat/freduce.cc
+++ b/passes/sat/freduce.cc
@@ -760,7 +760,7 @@ struct FreduceWorker
 
 struct FreducePass : public Pass {
 	FreducePass() : Pass("freduce", "perform functional reduction") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -791,7 +791,7 @@ struct FreducePass : public Pass {
 		log("circuit that is analyzed.\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
 	{
 		reduce_counter = 0;
 		reduce_stop_at = 0;
diff --git a/passes/sat/miter.cc b/passes/sat/miter.cc
index 9e150b60c..d37f1b126 100644
--- a/passes/sat/miter.cc
+++ b/passes/sat/miter.cc
@@ -358,7 +358,7 @@ void create_miter_assert(struct Pass *that, std::vector<std::string> args, RTLIL
 
 struct MiterPass : public Pass {
 	MiterPass() : Pass("miter", "automatically create a miter circuit") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -402,7 +402,7 @@ struct MiterPass : public Pass {
 		log("        call 'flatten; opt_expr -keepdc -undriven;;' on the miter circuit.\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() > 1 && args[1] == "-equiv") {
 			create_miter_equiv(this, args, design);
diff --git a/passes/sat/sat.cc b/passes/sat/sat.cc
index 6c0834deb..695a03e15 100644
--- a/passes/sat/sat.cc
+++ b/passes/sat/sat.cc
@@ -890,7 +890,7 @@ void print_qed()
 
 struct SatPass : public Pass {
 	SatPass() : Pass("sat", "solve a SAT problem in the circuit") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -1057,7 +1057,7 @@ struct SatPass : public Pass {
 		log("        Like -falsify but do not return an error for timeouts.\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
 	{
 		std::vector<std::pair<std::string, std::string>> sets, sets_init, prove, prove_x;
 		std::map<int, std::vector<std::pair<std::string, std::string>>> sets_at;
diff --git a/passes/sat/sim.cc b/passes/sat/sim.cc
index b49c12529..fadffcdbc 100644
--- a/passes/sat/sim.cc
+++ b/passes/sat/sim.cc
@@ -745,7 +745,7 @@ struct SimWorker : SimShared
 
 struct SimPass : public Pass {
 	SimPass() : Pass("sim", "simulate the circuit") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -787,7 +787,7 @@ struct SimPass : public Pass {
 		log("        enable debug output\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
 	{
 		SimWorker worker;
 		int numcycles = 20;
diff --git a/passes/techmap/abc.cc b/passes/techmap/abc.cc
index 18868c6d7..d2d15a4a9 100644
--- a/passes/techmap/abc.cc
+++ b/passes/techmap/abc.cc
@@ -1248,7 +1248,7 @@ void abc_module(RTLIL::Design *design, RTLIL::Module *current_module, std::strin
 
 struct AbcPass : public Pass {
 	AbcPass() : Pass("abc", "use ABC for technology mapping") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -1420,7 +1420,7 @@ struct AbcPass : public Pass {
 		log("[1] http://www.eecs.berkeley.edu/~alanmi/abc/\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
 	{
 		log_header(design, "Executing ABC pass (technology mapping using ABC).\n");
 		log_push();
diff --git a/passes/techmap/aigmap.cc b/passes/techmap/aigmap.cc
index b9ac7aded..35df2ff79 100644
--- a/passes/techmap/aigmap.cc
+++ b/passes/techmap/aigmap.cc
@@ -25,7 +25,7 @@ PRIVATE_NAMESPACE_BEGIN
 
 struct AigmapPass : public Pass {
 	AigmapPass() : Pass("aigmap", "map logic to and-inverter-graph circuit") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		log("\n");
 		log("    aigmap [options] [selection]\n");
@@ -37,7 +37,7 @@ struct AigmapPass : public Pass {
 		log("        Enable creation of $_NAND_ cells\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
 	{
 		bool nand_mode = false;
 
diff --git a/passes/techmap/alumacc.cc b/passes/techmap/alumacc.cc
index 95be7ab3b..dc7d416b0 100644
--- a/passes/techmap/alumacc.cc
+++ b/passes/techmap/alumacc.cc
@@ -539,7 +539,7 @@ struct AlumaccWorker
 
 struct AlumaccPass : public Pass {
 	AlumaccPass() : Pass("alumacc", "extract ALU and MACC cells") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -549,7 +549,7 @@ struct AlumaccPass : public Pass {
 		log("and $macc cells.\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
 	{
 		log_header(design, "Executing ALUMACC pass (create $alu and $macc cells).\n");
 
diff --git a/passes/techmap/attrmap.cc b/passes/techmap/attrmap.cc
index dec81d216..0b5576b06 100644
--- a/passes/techmap/attrmap.cc
+++ b/passes/techmap/attrmap.cc
@@ -81,7 +81,7 @@ struct AttrmapAction {
 
 struct AttrmapTocase : AttrmapAction {
 	string name;
-	virtual bool apply(IdString &id, Const&) {
+	bool apply(IdString &id, Const&) YS_OVERRIDE {
 		if (match_name(name, id, true))
 			id = RTLIL::escape_id(name);
 		return true;
@@ -90,7 +90,7 @@ struct AttrmapTocase : AttrmapAction {
 
 struct AttrmapRename : AttrmapAction {
 	string old_name, new_name;
-	virtual bool apply(IdString &id, Const&) {
+	bool apply(IdString &id, Const&) YS_OVERRIDE {
 		if (match_name(old_name, id))
 			id = RTLIL::escape_id(new_name);
 		return true;
@@ -101,7 +101,7 @@ struct AttrmapMap : AttrmapAction {
 	bool imap;
 	string old_name, new_name;
 	string old_value, new_value;
-	virtual bool apply(IdString &id, Const &val) {
+	bool apply(IdString &id, Const &val) YS_OVERRIDE {
 		if (match_name(old_name, id) && match_value(old_value, val, true)) {
 			id = RTLIL::escape_id(new_name);
 			val = make_value(new_value);
@@ -112,7 +112,7 @@ struct AttrmapMap : AttrmapAction {
 
 struct AttrmapRemove : AttrmapAction {
 	string name, value;
-	virtual bool apply(IdString &id, Const &val) {
+	bool apply(IdString &id, Const &val) YS_OVERRIDE {
 		return !(match_name(name, id) && match_value(value, val));
 	}
 };
@@ -144,7 +144,7 @@ void attrmap_apply(string objname, vector<std::unique_ptr<AttrmapAction>> &actio
 
 struct AttrmapPass : public Pass {
 	AttrmapPass() : Pass("attrmap", "renaming attributes") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -179,7 +179,7 @@ struct AttrmapPass : public Pass {
 		log("            -imap keep=\"false\" keep=0 -remove keep=0\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
 	{
 		log_header(design, "Executing ATTRMAP pass (move or copy attributes).\n");
 
diff --git a/passes/techmap/attrmvcp.cc b/passes/techmap/attrmvcp.cc
index 1537def00..e59aa6518 100644
--- a/passes/techmap/attrmvcp.cc
+++ b/passes/techmap/attrmvcp.cc
@@ -25,7 +25,7 @@ PRIVATE_NAMESPACE_BEGIN
 
 struct AttrmvcpPass : public Pass {
 	AttrmvcpPass() : Pass("attrmvcp", "move or copy attributes from wires to driving cells") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		log("\n");
 		log("    attrmvcp [options] [selection]\n");
@@ -53,7 +53,7 @@ struct AttrmvcpPass : public Pass {
 		log("        multiple times.\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
 	{
 		log_header(design, "Executing ATTRMVCP pass (move or copy attributes).\n");
 
diff --git a/passes/techmap/deminout.cc b/passes/techmap/deminout.cc
index 0b8fd5246..9f0c7bf67 100644
--- a/passes/techmap/deminout.cc
+++ b/passes/techmap/deminout.cc
@@ -25,7 +25,7 @@ PRIVATE_NAMESPACE_BEGIN
 
 struct DeminoutPass : public Pass {
 	DeminoutPass() : Pass("deminout", "demote inout ports to input or output") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		log("\n");
 		log("    deminout [options] [selection]\n");
@@ -33,7 +33,7 @@ struct DeminoutPass : public Pass {
 		log("\"Demote\" inout ports to input or output ports, if possible.\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
 	{
 		log_header(design, "Executing DEMINOUT pass (demote inout ports to input or output).\n");
 
diff --git a/passes/techmap/dff2dffe.cc b/passes/techmap/dff2dffe.cc
index 4d515f174..3291f5a4a 100644
--- a/passes/techmap/dff2dffe.cc
+++ b/passes/techmap/dff2dffe.cc
@@ -253,7 +253,7 @@ struct Dff2dffeWorker
 
 struct Dff2dffePass : public Pass {
 	Dff2dffePass() : Pass("dff2dffe", "transform $dff cells to $dffe cells") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -284,7 +284,7 @@ struct Dff2dffePass : public Pass {
 		log("        $_DFFE_[NP]_.\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
 	{
 		log_header(design, "Executing DFF2DFFE pass (transform $dff to $dffe where applicable).\n");
 
diff --git a/passes/techmap/dff2dffs.cc b/passes/techmap/dff2dffs.cc
index 0bfbdc965..39a4f6ade 100644
--- a/passes/techmap/dff2dffs.cc
+++ b/passes/techmap/dff2dffs.cc
@@ -26,7 +26,7 @@ PRIVATE_NAMESPACE_BEGIN
 
 struct Dff2dffsPass : public Pass {
 	Dff2dffsPass() : Pass("dff2dffs", "process sync set/reset with SR over CE priority") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		log("\n");
 		log("    dff2dffs [options] [selection]\n");
@@ -35,7 +35,7 @@ struct Dff2dffsPass : public Pass {
 		log("dff2dffe for SR over CE priority.\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
 	{
 		log_header(design, "Executing dff2dffs pass (merge synchronous set/reset into FF cells).\n");
 
diff --git a/passes/techmap/dffinit.cc b/passes/techmap/dffinit.cc
index 6a8a86383..a8eecc970 100644
--- a/passes/techmap/dffinit.cc
+++ b/passes/techmap/dffinit.cc
@@ -25,7 +25,7 @@ PRIVATE_NAMESPACE_BEGIN
 
 struct DffinitPass : public Pass {
 	DffinitPass() : Pass("dffinit", "set INIT param on FF cells") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -44,7 +44,7 @@ struct DffinitPass : public Pass {
 		log("        mode.)\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
 	{
 		log_header(design, "Executing DFFINIT pass (set INIT param on FF cells).\n");
 
diff --git a/passes/techmap/dfflibmap.cc b/passes/techmap/dfflibmap.cc
index 5ccb770c4..416ed2bd5 100644
--- a/passes/techmap/dfflibmap.cc
+++ b/passes/techmap/dfflibmap.cc
@@ -537,7 +537,7 @@ static void dfflibmap(RTLIL::Design *design, RTLIL::Module *module, bool prepare
 
 struct DfflibmapPass : public Pass {
 	DfflibmapPass() : Pass("dfflibmap", "technology mapping of flip-flops") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		log("\n");
 		log("    dfflibmap [-prepare] -liberty <file> [selection]\n");
@@ -553,7 +553,7 @@ struct DfflibmapPass : public Pass {
 		log("liberty file.\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
 	{
 		log_header(design, "Executing DFFLIBMAP pass (mapping DFF cells to sequential cells from liberty file).\n");
 
diff --git a/passes/techmap/dffsr2dff.cc b/passes/techmap/dffsr2dff.cc
index 0d4d53627..086a1d2fa 100644
--- a/passes/techmap/dffsr2dff.cc
+++ b/passes/techmap/dffsr2dff.cc
@@ -176,7 +176,7 @@ void adff_worker(SigMap &sigmap, Module *module, Cell *cell)
 
 struct Dffsr2dffPass : public Pass {
 	Dffsr2dffPass() : Pass("dffsr2dff", "convert DFFSR cells to simpler FF cell types") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -186,7 +186,7 @@ struct Dffsr2dffPass : public Pass {
 		log("$_DFF_???_) to simpler FF cell types when any of the set/reset inputs is unused.\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
 	{
 		log_header(design, "Executing DFFSR2DFF pass (mapping DFFSR cells to simpler FFs).\n");
 
diff --git a/passes/techmap/extract.cc b/passes/techmap/extract.cc
index 71e29c60b..fff90f13c 100644
--- a/passes/techmap/extract.cc
+++ b/passes/techmap/extract.cc
@@ -352,7 +352,7 @@ bool compareSortNeedleList(RTLIL::Module *left, RTLIL::Module *right)
 
 struct ExtractPass : public Pass {
 	ExtractPass() : Pass("extract", "find subcircuits and replace them with cells") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -440,7 +440,7 @@ struct ExtractPass : public Pass {
 		log("See 'help techmap' for a pass that does the opposite thing.\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
 	{
 		log_header(design, "Executing EXTRACT pass (map subcircuits to cells).\n");
 		log_push();
diff --git a/passes/techmap/extract_counter.cc b/passes/techmap/extract_counter.cc
index af0eb852a..a8d0bc834 100644
--- a/passes/techmap/extract_counter.cc
+++ b/passes/techmap/extract_counter.cc
@@ -559,7 +559,7 @@ void counter_worker(
 
 struct ExtractCounterPass : public Pass {
 	ExtractCounterPass() : Pass("extract_counter", "Extract GreenPak4 counter cells") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -578,7 +578,7 @@ struct ExtractCounterPass : public Pass {
 		log("\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
 	{
 		log_header(design, "Executing EXTRACT_COUNTER pass (find counters in netlist).\n");
 
diff --git a/passes/techmap/extract_fa.cc b/passes/techmap/extract_fa.cc
index a68cc5e2e..9e6dc0d24 100644
--- a/passes/techmap/extract_fa.cc
+++ b/passes/techmap/extract_fa.cc
@@ -531,7 +531,7 @@ struct ExtractFaWorker
 
 struct ExtractFaPass : public Pass {
 	ExtractFaPass() : Pass("extract_fa", "find and extract full/half adders") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -553,7 +553,7 @@ struct ExtractFaPass : public Pass {
 		log("        Verbose output\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
 	{
 		ExtractFaConfig config;
 
diff --git a/passes/techmap/extract_reduce.cc b/passes/techmap/extract_reduce.cc
index cc21c8665..a77bbc0b7 100644
--- a/passes/techmap/extract_reduce.cc
+++ b/passes/techmap/extract_reduce.cc
@@ -19,6 +19,7 @@
 
 #include "kernel/yosys.h"
 #include "kernel/sigtools.h"
+#include <deque>
 
 USING_YOSYS_NAMESPACE
 PRIVATE_NAMESPACE_BEGIN
@@ -33,7 +34,7 @@ struct ExtractReducePass : public Pass
 
 	ExtractReducePass() : Pass("extract_reduce", "converts gate chains into $reduce_* cells") { }
 
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -62,7 +63,7 @@ struct ExtractReducePass : public Pass
 				(cell->type == "$_XOR_" && gt == GateType::Xor);
 	}
 
-	virtual void execute(std::vector<std::string> args, RTLIL::Design *design)
+	void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
 	{
 		log_header(design, "Executing EXTRACT_REDUCE pass.\n");
 		log_push();
diff --git a/passes/techmap/hilomap.cc b/passes/techmap/hilomap.cc
index 82cecac26..9ec651aef 100644
--- a/passes/techmap/hilomap.cc
+++ b/passes/techmap/hilomap.cc
@@ -55,7 +55,7 @@ void hilomap_worker(RTLIL::SigSpec &sig)
 
 struct HilomapPass : public Pass {
 	HilomapPass() : Pass("hilomap", "technology mapping of constant hi- and/or lo-drivers") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		log("\n");
 		log("    hilomap [options] [selection]\n");
@@ -74,7 +74,7 @@ struct HilomapPass : public Pass {
 		log("        each constant bit.\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
 	{
 		log_header(design, "Executing HILOMAP pass (mapping to constant drivers).\n");
 
diff --git a/passes/techmap/insbuf.cc b/passes/techmap/insbuf.cc
index aa81468dc..2173049b4 100644
--- a/passes/techmap/insbuf.cc
+++ b/passes/techmap/insbuf.cc
@@ -25,7 +25,7 @@ PRIVATE_NAMESPACE_BEGIN
 
 struct InsbufPass : public Pass {
 	InsbufPass() : Pass("insbuf", "insert buffer cells for connected wires") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		log("\n");
 		log("    insbuf [options] [selection]\n");
@@ -37,7 +37,7 @@ struct InsbufPass : public Pass {
 		log("        call to \"clean\" will remove all $_BUF_ in the design.)\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
 	{
 		log_header(design, "Executing INSBUF pass (insert buffer cells for connected wires).\n");
 
diff --git a/passes/techmap/iopadmap.cc b/passes/techmap/iopadmap.cc
index 690ba87ed..efcc082d5 100644
--- a/passes/techmap/iopadmap.cc
+++ b/passes/techmap/iopadmap.cc
@@ -34,7 +34,7 @@ void split_portname_pair(std::string &port1, std::string &port2)
 
 struct IopadmapPass : public Pass {
 	IopadmapPass() : Pass("iopadmap", "technology mapping of i/o pads (or buffers)") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		log("\n");
 		log("    iopadmap [options] [selection]\n");
@@ -78,7 +78,7 @@ struct IopadmapPass : public Pass {
 		log("Tristate PADS (-toutpad, -tinoutpad) always operate in -bits mode.\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
 	{
 		log_header(design, "Executing IOPADMAP pass (mapping inputs/outputs to IO-PAD cells).\n");
 
diff --git a/passes/techmap/lut2mux.cc b/passes/techmap/lut2mux.cc
index 2bb0bd8b4..d32bbff14 100644
--- a/passes/techmap/lut2mux.cc
+++ b/passes/techmap/lut2mux.cc
@@ -56,7 +56,7 @@ int lut2mux(Cell *cell)
 
 struct Lut2muxPass : public Pass {
 	Lut2muxPass() : Pass("lut2mux", "convert $lut to $_MUX_") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -65,7 +65,7 @@ struct Lut2muxPass : public Pass {
 		log("This pass converts $lut cells to $_MUX_ gates.\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
 	{
 		log_header(design, "Executing LUT2MUX pass (convert $lut to $_MUX_).\n");
 
diff --git a/passes/techmap/maccmap.cc b/passes/techmap/maccmap.cc
index 32569d076..3e8e59e6b 100644
--- a/passes/techmap/maccmap.cc
+++ b/passes/techmap/maccmap.cc
@@ -365,7 +365,7 @@ PRIVATE_NAMESPACE_BEGIN
 
 struct MaccmapPass : public Pass {
 	MaccmapPass() : Pass("maccmap", "mapping macc cells") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -375,7 +375,7 @@ struct MaccmapPass : public Pass {
 		log("is used then the $macc cell is mapped to $add, $sub, etc. cells instead.\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
 	{
 		bool unmap_mode = false;
 
diff --git a/passes/techmap/muxcover.cc b/passes/techmap/muxcover.cc
index 1dc649587..12da9ed0c 100644
--- a/passes/techmap/muxcover.cc
+++ b/passes/techmap/muxcover.cc
@@ -561,7 +561,7 @@ struct MuxcoverWorker
 
 struct MuxcoverPass : public Pass {
 	MuxcoverPass() : Pass("muxcover", "cover trees of MUX cells with wider MUXes") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -579,7 +579,7 @@ struct MuxcoverPass : public Pass {
 		log("        less efficient than the original circuit.\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
 	{
 		log_header(design, "Executing MUXCOVER pass (mapping to wider MUXes).\n");
 
diff --git a/passes/techmap/nlutmap.cc b/passes/techmap/nlutmap.cc
index f1a41cc3e..cc765d89c 100644
--- a/passes/techmap/nlutmap.cc
+++ b/passes/techmap/nlutmap.cc
@@ -129,7 +129,7 @@ struct NlutmapWorker
 
 struct NlutmapPass : public Pass {
 	NlutmapPass() : Pass("nlutmap", "map to LUTs of different sizes") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -149,7 +149,7 @@ struct NlutmapPass : public Pass {
 		log("to generic logic gates ($_AND_, etc.).\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
 	{
 		NlutmapConfig config;
 
diff --git a/passes/techmap/pmuxtree.cc b/passes/techmap/pmuxtree.cc
index c626dbcc5..b7a22dc3b 100644
--- a/passes/techmap/pmuxtree.cc
+++ b/passes/techmap/pmuxtree.cc
@@ -67,7 +67,7 @@ static SigSpec recursive_mux_generator(Module *module, const SigSpec &sig_data,
 
 struct PmuxtreePass : public Pass {
 	PmuxtreePass() : Pass("pmuxtree", "transform $pmux cells to trees of $mux cells") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -76,7 +76,7 @@ struct PmuxtreePass : public Pass {
 		log("This pass transforms $pmux cells to a trees of $mux cells.\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
 	{
 		log_header(design, "Executing PMUXTREE pass.\n");
 
diff --git a/passes/techmap/shregmap.cc b/passes/techmap/shregmap.cc
index 6936b499e..f20863ba0 100644
--- a/passes/techmap/shregmap.cc
+++ b/passes/techmap/shregmap.cc
@@ -391,7 +391,7 @@ struct ShregmapWorker
 
 struct ShregmapPass : public Pass {
 	ShregmapPass() : Pass("shregmap", "map shift registers") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -449,7 +449,7 @@ struct ShregmapPass : public Pass {
 		log("        map to greenpak4 shift registers.\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
 	{
 		ShregmapOptions opts;
 		string clkpol, enpol;
diff --git a/passes/techmap/simplemap.cc b/passes/techmap/simplemap.cc
index c6b932bdc..660b60601 100644
--- a/passes/techmap/simplemap.cc
+++ b/passes/techmap/simplemap.cc
@@ -575,7 +575,7 @@ PRIVATE_NAMESPACE_BEGIN
 
 struct SimplemapPass : public Pass {
 	SimplemapPass() : Pass("simplemap", "mapping simple coarse-grain cells") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -590,7 +590,7 @@ struct SimplemapPass : public Pass {
 		log("  $sr, $ff, $dff, $dffsr, $adff, $dlatch\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
 	{
 		log_header(design, "Executing SIMPLEMAP pass (map simple cells to gate primitives).\n");
 		extra_args(args, 1, design);
diff --git a/passes/techmap/techmap.cc b/passes/techmap/techmap.cc
index 1908ae8b5..d0e5e2236 100644
--- a/passes/techmap/techmap.cc
+++ b/passes/techmap/techmap.cc
@@ -891,7 +891,7 @@ struct TechmapWorker
 
 struct TechmapPass : public Pass {
 	TechmapPass() : Pass("techmap", "generic technology mapper") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -1022,7 +1022,7 @@ struct TechmapPass : public Pass {
 		log("essentially techmap but using the design itself as map library).\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
 	{
 		log_header(design, "Executing TECHMAP pass (map to technology primitives).\n");
 		log_push();
@@ -1141,7 +1141,7 @@ struct TechmapPass : public Pass {
 
 struct FlattenPass : public Pass {
 	FlattenPass() : Pass("flatten", "flatten design") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -1155,7 +1155,7 @@ struct FlattenPass : public Pass {
 		log("flattened by this command.\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
 	{
 		log_header(design, "Executing FLATTEN pass (flatten design).\n");
 		log_push();
diff --git a/passes/techmap/tribuf.cc b/passes/techmap/tribuf.cc
index 03629082c..587cb9038 100644
--- a/passes/techmap/tribuf.cc
+++ b/passes/techmap/tribuf.cc
@@ -139,7 +139,7 @@ struct TribufWorker {
 
 struct TribufPass : public Pass {
 	TribufPass() : Pass("tribuf", "infer tri-state buffers") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -156,7 +156,7 @@ struct TribufPass : public Pass {
 		log("        to non-tristate logic. this option implies -merge.\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
 	{
 		TribufConfig config;
 
diff --git a/passes/techmap/zinit.cc b/passes/techmap/zinit.cc
index a577e1235..b46147fb9 100644
--- a/passes/techmap/zinit.cc
+++ b/passes/techmap/zinit.cc
@@ -25,7 +25,7 @@ PRIVATE_NAMESPACE_BEGIN
 
 struct ZinitPass : public Pass {
 	ZinitPass() : Pass("zinit", "add inverters so all FF are zero-initialized") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -37,7 +37,7 @@ struct ZinitPass : public Pass {
 		log("        also add zero initialization to uninitialized FFs\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
 	{
 		bool all_mode = false;
 
diff --git a/passes/tests/test_abcloop.cc b/passes/tests/test_abcloop.cc
index 09cb41954..5d5466afe 100644
--- a/passes/tests/test_abcloop.cc
+++ b/passes/tests/test_abcloop.cc
@@ -244,7 +244,7 @@ static void test_abcloop()
 
 struct TestAbcloopPass : public Pass {
 	TestAbcloopPass() : Pass("test_abcloop", "automatically test handling of loops in abc command") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -259,7 +259,7 @@ struct TestAbcloopPass : public Pass {
 		log("        use this value as rng seed value (default = unix time).\n");
 		log("\n");
 	}
-	virtual void execute(std::vector<std::string> args, RTLIL::Design*)
+	void execute(std::vector<std::string> args, RTLIL::Design*) YS_OVERRIDE
 	{
 		int num_iter = 100;
 		xorshift32_state = 0;
diff --git a/passes/tests/test_autotb.cc b/passes/tests/test_autotb.cc
index cb31056f4..bfb1d6642 100644
--- a/passes/tests/test_autotb.cc
+++ b/passes/tests/test_autotb.cc
@@ -324,7 +324,7 @@ static void autotest(std::ostream &f, RTLIL::Design *design, int num_iter, int s
 
 struct TestAutotbBackend : public Backend {
 	TestAutotbBackend() : Backend("=test_autotb", "generate simple test benches") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -349,7 +349,7 @@ struct TestAutotbBackend : public Backend {
 		log("        number of iterations the test bench should run (default = 1000)\n");
 		log("\n");
 	}
-	virtual void execute(std::ostream *&f, std::string filename, std::vector<std::string> args, RTLIL::Design *design)
+	void execute(std::ostream *&f, std::string filename, std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
 	{
 		int num_iter = 1000;
 		int seed = 0;
diff --git a/passes/tests/test_cell.cc b/passes/tests/test_cell.cc
index 47b6bdf23..e360b5edb 100644
--- a/passes/tests/test_cell.cc
+++ b/passes/tests/test_cell.cc
@@ -652,7 +652,7 @@ static void run_eval_test(RTLIL::Design *design, bool verbose, bool nosat, std::
 
 struct TestCellPass : public Pass {
 	TestCellPass() : Pass("test_cell", "automatically test the implementation of a cell type") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -712,7 +712,7 @@ struct TestCellPass : public Pass {
 		log("        create a Verilog test bench to test simlib and write_verilog\n");
 		log("\n");
 	}
-	virtual void execute(std::vector<std::string> args, RTLIL::Design*)
+	void execute(std::vector<std::string> args, RTLIL::Design*) YS_OVERRIDE
 	{
 		int num_iter = 100;
 		std::string techmap_cmd = "techmap -assert";
diff --git a/techlibs/achronix/synth_achronix.cc b/techlibs/achronix/synth_achronix.cc
index 7f4503070..92b10781d 100755
--- a/techlibs/achronix/synth_achronix.cc
+++ b/techlibs/achronix/synth_achronix.cc
@@ -28,7 +28,7 @@ PRIVATE_NAMESPACE_BEGIN
 struct SynthAchronixPass : public ScriptPass {
   SynthAchronixPass() : ScriptPass("synth_achronix", "synthesis for Acrhonix Speedster22i FPGAs.") { }
 
-  virtual void help() YS_OVERRIDE
+  void help() YS_OVERRIDE
   {
     //   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
     log("\n");
@@ -63,7 +63,7 @@ struct SynthAchronixPass : public ScriptPass {
   string top_opt, family_opt, vout_file;
   bool retime, flatten;
 
-  virtual void clear_flags() YS_OVERRIDE
+  void clear_flags() YS_OVERRIDE
   {
     top_opt = "-auto-top";
     vout_file = "";
@@ -71,7 +71,7 @@ struct SynthAchronixPass : public ScriptPass {
     flatten = true;
   }
 
-  virtual void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
+  void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
   {
     string run_from, run_to;
     clear_flags();
@@ -118,7 +118,7 @@ struct SynthAchronixPass : public ScriptPass {
     log_pop();
   }
 
-  virtual void script() YS_OVERRIDE
+  void script() YS_OVERRIDE
   {
     if (check_label("begin"))
       {
diff --git a/techlibs/common/prep.cc b/techlibs/common/prep.cc
index cc977f97e..897f37dbb 100644
--- a/techlibs/common/prep.cc
+++ b/techlibs/common/prep.cc
@@ -29,7 +29,7 @@ struct PrepPass : public ScriptPass
 {
 	PrepPass() : ScriptPass("prep", "generic synthesis script") { }
 
-	virtual void help() YS_OVERRIDE
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -81,7 +81,7 @@ struct PrepPass : public ScriptPass
 	string top_module, fsm_opts;
 	bool autotop, flatten, ifxmode, memxmode, nomemmode, nokeepdc, nordff;
 
-	virtual void clear_flags() YS_OVERRIDE
+	void clear_flags() YS_OVERRIDE
 	{
 		top_module.clear();
 
@@ -94,7 +94,7 @@ struct PrepPass : public ScriptPass
 		nordff = true;
 	}
 
-	virtual void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
+	void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
 	{
 		string run_from, run_to;
 
@@ -163,7 +163,7 @@ struct PrepPass : public ScriptPass
 		log_pop();
 	}
 
-	virtual void script() YS_OVERRIDE
+	void script() YS_OVERRIDE
 	{
 
 		if (check_label("begin"))
diff --git a/techlibs/common/synth.cc b/techlibs/common/synth.cc
index 4ca34839e..efb214759 100644
--- a/techlibs/common/synth.cc
+++ b/techlibs/common/synth.cc
@@ -29,7 +29,7 @@ struct SynthPass : public ScriptPass
 {
 	SynthPass() : ScriptPass("synth", "generic synthesis script") { }
 
-	virtual void help() YS_OVERRIDE
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -81,7 +81,7 @@ struct SynthPass : public ScriptPass
 	string top_module, fsm_opts, memory_opts;
 	bool autotop, flatten, noalumacc, nofsm, noabc, noshare;
 
-	virtual void clear_flags() YS_OVERRIDE
+	void clear_flags() YS_OVERRIDE
 	{
 		top_module.clear();
 		fsm_opts.clear();
@@ -95,7 +95,7 @@ struct SynthPass : public ScriptPass
 		noshare = false;
 	}
 
-	virtual void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
+	void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
 	{
 		string run_from, run_to;
 		clear_flags();
@@ -165,7 +165,7 @@ struct SynthPass : public ScriptPass
 		log_pop();
 	}
 
-	virtual void script() YS_OVERRIDE
+	void script() YS_OVERRIDE
 	{
 		if (check_label("begin"))
 		{
diff --git a/techlibs/coolrunner2/coolrunner2_sop.cc b/techlibs/coolrunner2/coolrunner2_sop.cc
index 431e0a127..48da0d8ad 100644
--- a/techlibs/coolrunner2/coolrunner2_sop.cc
+++ b/techlibs/coolrunner2/coolrunner2_sop.cc
@@ -25,7 +25,7 @@ PRIVATE_NAMESPACE_BEGIN
 
 struct Coolrunner2SopPass : public Pass {
 	Coolrunner2SopPass() : Pass("coolrunner2_sop", "break $sop cells into ANDTERM/ORTERM cells") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		log("\n");
 		log("    coolrunner2_sop [options] [selection]\n");
@@ -33,7 +33,7 @@ struct Coolrunner2SopPass : public Pass {
 		log("Break $sop cells into ANDTERM/ORTERM cells.\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
 	{
 		log_header(design, "Executing COOLRUNNER2_SOP pass (break $sop cells into ANDTERM/ORTERM cells).\n");
 		extra_args(args, 1, design);
diff --git a/techlibs/coolrunner2/synth_coolrunner2.cc b/techlibs/coolrunner2/synth_coolrunner2.cc
index 2e94c3449..a5dac3566 100644
--- a/techlibs/coolrunner2/synth_coolrunner2.cc
+++ b/techlibs/coolrunner2/synth_coolrunner2.cc
@@ -29,7 +29,7 @@ struct SynthCoolrunner2Pass : public ScriptPass
 {
 	SynthCoolrunner2Pass() : ScriptPass("synth_coolrunner2", "synthesis for Xilinx Coolrunner-II CPLDs") { }
 
-	virtual void help() YS_OVERRIDE
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -66,7 +66,7 @@ struct SynthCoolrunner2Pass : public ScriptPass
 	string top_opt, json_file;
 	bool flatten, retime;
 
-	virtual void clear_flags() YS_OVERRIDE
+	void clear_flags() YS_OVERRIDE
 	{
 		top_opt = "-auto-top";
 		json_file = "";
@@ -74,7 +74,7 @@ struct SynthCoolrunner2Pass : public ScriptPass
 		retime = false;
 	}
 
-	virtual void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
+	void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
 	{
 		string run_from, run_to;
 		clear_flags();
@@ -121,7 +121,7 @@ struct SynthCoolrunner2Pass : public ScriptPass
 		log_pop();
 	}
 
-	virtual void script() YS_OVERRIDE
+	void script() YS_OVERRIDE
 	{
 		if (check_label("begin"))
 		{
diff --git a/techlibs/easic/synth_easic.cc b/techlibs/easic/synth_easic.cc
index e17138f3a..b5ed93be4 100644
--- a/techlibs/easic/synth_easic.cc
+++ b/techlibs/easic/synth_easic.cc
@@ -29,7 +29,7 @@ struct SynthEasicPass : public ScriptPass
 {
 	SynthEasicPass() : ScriptPass("synth_easic", "synthesis for eASIC platform") { }
 
-	virtual void help() YS_OVERRIDE
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -67,7 +67,7 @@ struct SynthEasicPass : public ScriptPass
 	string top_opt, vlog_file, etools_path;
 	bool flatten, retime;
 
-	virtual void clear_flags() YS_OVERRIDE
+	void clear_flags() YS_OVERRIDE
 	{
 		top_opt = "-auto-top";
 		vlog_file = "";
@@ -76,7 +76,7 @@ struct SynthEasicPass : public ScriptPass
 		retime = false;
 	}
 
-	virtual void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
+	void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
 	{
 		string run_from, run_to;
 		clear_flags();
@@ -127,7 +127,7 @@ struct SynthEasicPass : public ScriptPass
 		log_pop();
 	}
 
-	virtual void script() YS_OVERRIDE
+	void script() YS_OVERRIDE
 	{
 		string phys_clk_lib = stringf("%s/data_ruby28/design_libs/logical/timing/gp/n3x_phys_clk_0v893ff125c.lib", etools_path.c_str());
 		string logic_lut_lib = stringf("%s/data_ruby28/design_libs/logical/timing/gp/n3x_logic_lut_0v893ff125c.lib", etools_path.c_str());
diff --git a/techlibs/ecp5/synth_ecp5.cc b/techlibs/ecp5/synth_ecp5.cc
index 76051d1a2..a13dd8d41 100644
--- a/techlibs/ecp5/synth_ecp5.cc
+++ b/techlibs/ecp5/synth_ecp5.cc
@@ -30,7 +30,7 @@ struct SynthEcp5Pass : public ScriptPass
 {
 	SynthEcp5Pass() : ScriptPass("synth_ecp5", "synthesis for ECP5 FPGAs") { }
 
-	virtual void help() YS_OVERRIDE
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -95,7 +95,7 @@ struct SynthEcp5Pass : public ScriptPass
 	string top_opt, blif_file, edif_file, json_file;
 	bool noccu2, nodffe, nobram, nodram, nomux, flatten, retime, abc2, vpr;
 
-	virtual void clear_flags() YS_OVERRIDE
+	void clear_flags() YS_OVERRIDE
 	{
 		top_opt = "-auto-top";
 		blif_file = "";
@@ -112,7 +112,7 @@ struct SynthEcp5Pass : public ScriptPass
 		vpr = false;
 	}
 
-	virtual void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
+	void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
 	{
 		string run_from, run_to;
 		clear_flags();
@@ -199,7 +199,7 @@ struct SynthEcp5Pass : public ScriptPass
 		log_pop();
 	}
 
-	virtual void script() YS_OVERRIDE
+	void script() YS_OVERRIDE
 	{
 		if (check_label("begin"))
 		{
diff --git a/techlibs/gowin/synth_gowin.cc b/techlibs/gowin/synth_gowin.cc
index 44dec265d..793f345be 100644
--- a/techlibs/gowin/synth_gowin.cc
+++ b/techlibs/gowin/synth_gowin.cc
@@ -29,7 +29,7 @@ struct SynthGowinPass : public ScriptPass
 {
 	SynthGowinPass() : ScriptPass("synth_gowin", "synthesis for Gowin FPGAs") { }
 
-	virtual void help() YS_OVERRIDE
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -61,14 +61,14 @@ struct SynthGowinPass : public ScriptPass
 	string top_opt, vout_file;
 	bool retime;
 
-	virtual void clear_flags() YS_OVERRIDE
+	void clear_flags() YS_OVERRIDE
 	{
 		top_opt = "-auto-top";
 		vout_file = "";
 		retime = false;
 	}
 
-	virtual void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
+	void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
 	{
 		string run_from, run_to;
 		clear_flags();
@@ -111,7 +111,7 @@ struct SynthGowinPass : public ScriptPass
 		log_pop();
 	}
 
-	virtual void script() YS_OVERRIDE
+	void script() YS_OVERRIDE
 	{
 		if (check_label("begin"))
 		{
diff --git a/techlibs/greenpak4/greenpak4_dffinv.cc b/techlibs/greenpak4/greenpak4_dffinv.cc
index 7d9d7d5b0..d57e978a0 100644
--- a/techlibs/greenpak4/greenpak4_dffinv.cc
+++ b/techlibs/greenpak4/greenpak4_dffinv.cc
@@ -91,7 +91,7 @@ void invert_gp_dff(Cell *cell, bool invert_input)
 
 struct Greenpak4DffInvPass : public Pass {
 	Greenpak4DffInvPass() : Pass("greenpak4_dffinv", "merge greenpak4 inverters and DFF/latches") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		log("\n");
 		log("    greenpak4_dffinv [options] [selection]\n");
@@ -99,7 +99,7 @@ struct Greenpak4DffInvPass : public Pass {
 		log("Merge GP_INV cells with GP_DFF* and GP_DLATCH* cells.\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
 	{
 		log_header(design, "Executing GREENPAK4_DFFINV pass (merge input/output inverters into FF/latch cells).\n");
 
diff --git a/techlibs/greenpak4/synth_greenpak4.cc b/techlibs/greenpak4/synth_greenpak4.cc
index 5e0e9e5d5..b91d5273a 100644
--- a/techlibs/greenpak4/synth_greenpak4.cc
+++ b/techlibs/greenpak4/synth_greenpak4.cc
@@ -29,7 +29,7 @@ struct SynthGreenPAK4Pass : public ScriptPass
 {
 	SynthGreenPAK4Pass() : ScriptPass("synth_greenpak4", "synthesis for GreenPAK4 FPGAs") { }
 
-	virtual void help() YS_OVERRIDE
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -70,7 +70,7 @@ struct SynthGreenPAK4Pass : public ScriptPass
 	string top_opt, part, json_file;
 	bool flatten, retime;
 
-	virtual void clear_flags() YS_OVERRIDE
+	void clear_flags() YS_OVERRIDE
 	{
 		top_opt = "-auto-top";
 		part = "SLG46621V";
@@ -79,7 +79,7 @@ struct SynthGreenPAK4Pass : public ScriptPass
 		retime = false;
 	}
 
-	virtual void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
+	void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
 	{
 		string run_from, run_to;
 		clear_flags();
@@ -133,7 +133,7 @@ struct SynthGreenPAK4Pass : public ScriptPass
 		log_pop();
 	}
 
-	virtual void script() YS_OVERRIDE
+	void script() YS_OVERRIDE
 	{
 		if (check_label("begin"))
 		{
diff --git a/techlibs/ice40/ice40_ffinit.cc b/techlibs/ice40/ice40_ffinit.cc
index c914b20e8..3089d8932 100644
--- a/techlibs/ice40/ice40_ffinit.cc
+++ b/techlibs/ice40/ice40_ffinit.cc
@@ -25,7 +25,7 @@ PRIVATE_NAMESPACE_BEGIN
 
 struct Ice40FfinitPass : public Pass {
 	Ice40FfinitPass() : Pass("ice40_ffinit", "iCE40: handle FF init values") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -35,7 +35,7 @@ struct Ice40FfinitPass : public Pass {
 		log("nonzero init values.\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
 	{
 		log_header(design, "Executing ICE40_FFINIT pass (implement FF init values).\n");
 
diff --git a/techlibs/ice40/ice40_ffssr.cc b/techlibs/ice40/ice40_ffssr.cc
index 9afbc0fce..668df09dd 100644
--- a/techlibs/ice40/ice40_ffssr.cc
+++ b/techlibs/ice40/ice40_ffssr.cc
@@ -25,7 +25,7 @@ PRIVATE_NAMESPACE_BEGIN
 
 struct Ice40FfssrPass : public Pass {
 	Ice40FfssrPass() : Pass("ice40_ffssr", "iCE40: merge synchronous set/reset into FF cells") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		log("\n");
 		log("    ice40_ffssr [options] [selection]\n");
@@ -33,7 +33,7 @@ struct Ice40FfssrPass : public Pass {
 		log("Merge synchronous set/reset $_MUX_ cells into iCE40 FFs.\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
 	{
 		log_header(design, "Executing ICE40_FFSSR pass (merge synchronous set/reset into FF cells).\n");
 
diff --git a/techlibs/ice40/ice40_opt.cc b/techlibs/ice40/ice40_opt.cc
index 7af60f297..162740059 100644
--- a/techlibs/ice40/ice40_opt.cc
+++ b/techlibs/ice40/ice40_opt.cc
@@ -136,7 +136,7 @@ static void run_ice40_opts(Module *module, bool unlut_mode)
 
 struct Ice40OptPass : public Pass {
 	Ice40OptPass() : Pass("ice40_opt", "iCE40: perform simple optimizations") { }
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -156,7 +156,7 @@ struct Ice40OptPass : public Pass {
 		log("mapped SB_LUT4 cells back to logic.\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
 	{
 		string opt_expr_args = "-mux_undef -undriven";
 		bool unlut_mode = false;
diff --git a/techlibs/ice40/synth_ice40.cc b/techlibs/ice40/synth_ice40.cc
index abd890a56..b0687e5e3 100644
--- a/techlibs/ice40/synth_ice40.cc
+++ b/techlibs/ice40/synth_ice40.cc
@@ -29,7 +29,7 @@ struct SynthIce40Pass : public ScriptPass
 {
 	SynthIce40Pass() : ScriptPass("synth_ice40", "synthesis for iCE40 FPGAs") { }
 
-	virtual void help() YS_OVERRIDE
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -88,7 +88,7 @@ struct SynthIce40Pass : public ScriptPass
 	string top_opt, blif_file, edif_file, json_file;
 	bool nocarry, nodffe, nobram, flatten, retime, abc2, vpr;
 
-	virtual void clear_flags() YS_OVERRIDE
+	void clear_flags() YS_OVERRIDE
 	{
 		top_opt = "-auto-top";
 		blif_file = "";
@@ -103,7 +103,7 @@ struct SynthIce40Pass : public ScriptPass
 		vpr = false;
 	}
 
-	virtual void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
+	void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
 	{
 		string run_from, run_to;
 		clear_flags();
@@ -182,7 +182,7 @@ struct SynthIce40Pass : public ScriptPass
 		log_pop();
 	}
 
-	virtual void script() YS_OVERRIDE
+	void script() YS_OVERRIDE
 	{
 		if (check_label("begin"))
 		{
diff --git a/techlibs/intel/synth_intel.cc b/techlibs/intel/synth_intel.cc
index c51949bd4..d74f295ec 100644
--- a/techlibs/intel/synth_intel.cc
+++ b/techlibs/intel/synth_intel.cc
@@ -28,7 +28,7 @@ PRIVATE_NAMESPACE_BEGIN
 struct SynthIntelPass : public ScriptPass {
   SynthIntelPass() : ScriptPass("synth_intel", "synthesis for Intel (Altera) FPGAs.") { }
 
-  virtual void help() YS_OVERRIDE
+  void help() YS_OVERRIDE
   {
     //   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
     log("\n");
@@ -79,7 +79,7 @@ struct SynthIntelPass : public ScriptPass {
   string top_opt, family_opt, vout_file, blif_file;
   bool retime, flatten, nobram, noiopads;
 
-  virtual void clear_flags() YS_OVERRIDE
+  void clear_flags() YS_OVERRIDE
   {
     top_opt = "-auto-top";
     family_opt = "max10";
@@ -91,7 +91,7 @@ struct SynthIntelPass : public ScriptPass {
     noiopads = false;
   }
 
-  virtual void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
+  void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
   {
     string run_from, run_to;
     clear_flags();
@@ -156,7 +156,7 @@ struct SynthIntelPass : public ScriptPass {
     log_pop();
   }
 
-  virtual void script() YS_OVERRIDE
+  void script() YS_OVERRIDE
   {
     if (check_label("begin"))
       {
@@ -255,7 +255,7 @@ struct SynthIntelPass : public ScriptPass {
           run(stringf("write_verilog -attr2comment -defparam -nohex -decimal -renameprefix syn_ %s",
                       help_mode ? "<file-name>" : vout_file.c_str()));
       }
-    
+
     if (check_label("vpr"))
       {
         if (!blif_file.empty() || help_mode)
@@ -264,7 +264,7 @@ struct SynthIntelPass : public ScriptPass {
             run(stringf("write_blif %s", help_mode ? "<file-name>" : blif_file.c_str()));
           }
       }
-  }       
+  }
 } SynthIntelPass;
 
 PRIVATE_NAMESPACE_END
diff --git a/techlibs/xilinx/synth_xilinx.cc b/techlibs/xilinx/synth_xilinx.cc
index 1bc61daef..590fe61d2 100644
--- a/techlibs/xilinx/synth_xilinx.cc
+++ b/techlibs/xilinx/synth_xilinx.cc
@@ -38,7 +38,7 @@ struct SynthXilinxPass : public Pass
 {
 	SynthXilinxPass() : Pass("synth_xilinx", "synthesis for Xilinx FPGAs") { }
 
-	virtual void help()
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -128,7 +128,7 @@ struct SynthXilinxPass : public Pass
 		log("        write_blif <file-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
 	{
 		std::string top_opt = "-auto-top";
 		std::string edif_file;
diff --git a/tests/various/reg_wire_error.sv b/tests/various/reg_wire_error.sv
new file mode 100644
index 000000000..fe5ff3abd
--- /dev/null
+++ b/tests/various/reg_wire_error.sv
@@ -0,0 +1,74 @@
+module sub_mod(input i_in, output o_out);
+assign o_out = i_in;
+endmodule
+
+module test(i_clk, i, i_reg, o_reg, o_wire, o_mr, o_mw, o_ml);
+input i_clk;
+input i;
+input i_reg;
+output o_reg;
+output o_wire;
+output o_mr, o_mw, o_ml;
+
+// Enable this to see how it doesn't fail on yosys although it should
+//reg o_wire;
+// Enable this instead of the above to see how logic can be mapped to a wire
+logic o_wire;
+// Enable this to see how it doesn't fail on yosys although it should
+//reg i_reg;
+// Disable this to see how it doesn't fail on yosys although it should
+//reg o_reg;
+
+logic l_reg;
+
+// Enable this to tst if logic-turne-reg will catch assignments even if done before it turned into a reg
+assign l_reg = !o_reg;
+initial o_reg = 1'b0;
+always @(posedge i_clk)
+begin
+  o_reg <= !o_reg;
+  l_reg <= !o_reg;
+end
+
+assign o_wire = !o_reg;
+// Uncomment this to see how a logic already turned intoa reg can be freely assigned on yosys
+assign l_reg = !o_reg;
+
+sub_mod sm_inst (
+  .i_in(1'b1),
+  .o_out(o_reg)
+);
+
+wire   mw1[0:1];
+wire   mw2[0:1];
+wire   mw3[0:1];
+reg    mr1[0:1];
+reg    mr2[0:1];
+reg    mr3[0:1];
+logic  ml1[0:1];
+logic  ml2[0:1];
+logic  ml3[0:1];
+
+assign o_mw = mw1[i];
+assign o_mr = mr1[i];
+assign o_ml = ml1[i];
+
+assign mw1[1] = 1'b1;
+//assign mr1[1] = 1'b1;
+assign ml1[1] = 1'b1;
+always @(posedge i_clk)
+begin
+  mr2[0] = 1'b0;
+  mw2[0] = 1'b0;
+  ml2[0] = 1'b0;
+end
+
+always @(posedge i_clk)
+begin
+  mr3[0] <= 1'b0;
+  mw3[0] <= 1'b0;
+  ml3[0] <= 1'b0;
+end
+
+endmodule
+
diff --git a/tests/various/reg_wire_error.ys b/tests/various/reg_wire_error.ys
new file mode 100644
index 000000000..b9d03155d
--- /dev/null
+++ b/tests/various/reg_wire_error.ys
@@ -0,0 +1 @@
+read_verilog -sv reg_wire_error.sv