Started implementing undef handling in satgen

1 files changed, 172 insertions, 25 deletions

diff --git a/kernel/satgen.h b/kernel/satgen.h
index 3c63f9168..3c19f1740 100644
--- a/kernel/satgen.h
+++ b/kernel/satgen.h
@@ -40,9 +40,10 @@ struct SatGen
 	std::string prefix;
 	SigPool initial_state;
 	bool ignore_div_by_zero;
+	bool model_undef;
 
 	SatGen(ezSAT *ez, RTLIL::Design *design, SigMap *sigmap, std::string prefix = std::string()) :
-			ez(ez), design(design), sigmap(sigmap), prefix(prefix), ignore_div_by_zero(false)
+			ez(ez), design(design), sigmap(sigmap), prefix(prefix), ignore_div_by_zero(false), model_undef(false)
 	{
 	}
 
@@ -53,9 +54,9 @@ struct SatGen
 		this->prefix = prefix;
 	}
 
-	std::vector<int> importSigSpec(RTLIL::SigSpec sig, int timestep = -1)
+	std::vector<int> importSigSpecWorker(RTLIL::SigSpec &sig, std::string &pf, bool undef_mode)
 	{
-		assert(timestep < 0 || timestep > 0);
+		assert(!undef_mode || model_undef);
 		sigmap->apply(sig);
 		sig.expand();
 
@@ -64,20 +65,33 @@ struct SatGen
 
 		for (auto &c : sig.chunks)
 			if (c.wire == NULL) {
-				vec.push_back(c.data.as_bool() ? ez->TRUE : ez->FALSE);
+				vec.push_back(c.data.bits.at(0) == (undef_mode ? RTLIL::State::Sx : RTLIL::State::S1) ? ez->TRUE : ez->FALSE);
 			} else {
-				std::string name = prefix;
-				name += timestep == -1 ? "" : stringf("@%d:", timestep);
-				name += stringf(c.wire->width == 1 ?  "%s" : "%s [%d]", RTLIL::id2cstr(c.wire->name), c.offset);
+				std::string name = pf + stringf(c.wire->width == 1 ?  "%s" : "%s [%d]", RTLIL::id2cstr(c.wire->name), c.offset);
 				vec.push_back(ez->literal(name));
 			}
 		return vec;
 	}
 
-	void extendSignalWidth(std::vector<int> &vec_a, std::vector<int> &vec_b, RTLIL::Cell *cell, size_t y_width = 0)
+	std::vector<int> importSigSpec(RTLIL::SigSpec sig, int timestep = -1)
+	{
+		assert(timestep != 0);
+		std::string pf = prefix + (timestep == -1 ? "" : stringf("@%d:", timestep));
+		return importSigSpecWorker(sig, pf, false);
+	}
+
+	std::vector<int> importUndefSigSpec(RTLIL::SigSpec sig, int timestep = -1)
+	{
+		assert(timestep != 0);
+		std::string pf = "undef:" + prefix + (timestep == -1 ? "" : stringf("@%d:", timestep));
+		return importSigSpecWorker(sig, pf, true);
+	}
+
+	void extendSignalWidth(std::vector<int> &vec_a, std::vector<int> &vec_b, RTLIL::Cell *cell, size_t y_width = 0, bool undef_mode = false)
 	{
-		bool is_signed = false;
-		if (cell->parameters.count("\\A_SIGNED") > 0 && cell->parameters.count("\\B_SIGNED") > 0)
+		assert(!undef_mode || model_undef);
+		bool is_signed = undef_mode;
+		if (!undef_mode && cell->parameters.count("\\A_SIGNED") > 0 && cell->parameters.count("\\B_SIGNED") > 0)
 			is_signed = cell->parameters["\\A_SIGNED"].as_bool() && cell->parameters["\\B_SIGNED"].as_bool();
 		while (vec_a.size() < vec_b.size() || vec_a.size() < y_width)
 			vec_a.push_back(is_signed && vec_a.size() > 0 ? vec_a.back() : ez->FALSE);
@@ -85,16 +99,18 @@ struct SatGen
 			vec_b.push_back(is_signed && vec_b.size() > 0 ? vec_b.back() : ez->FALSE);
 	}
 
-	void extendSignalWidth(std::vector<int> &vec_a, std::vector<int> &vec_b, std::vector<int> &vec_y, RTLIL::Cell *cell)
+	void extendSignalWidth(std::vector<int> &vec_a, std::vector<int> &vec_b, std::vector<int> &vec_y, RTLIL::Cell *cell, bool undef_mode = false)
 	{
-		extendSignalWidth(vec_a, vec_b, cell, vec_y.size());
+		assert(!undef_mode || model_undef);
+		extendSignalWidth(vec_a, vec_b, cell, vec_y.size(), undef_mode);
 		while (vec_y.size() < vec_a.size())
 			vec_y.push_back(ez->literal());
 	}
 
-	void extendSignalWidthUnary(std::vector<int> &vec_a, std::vector<int> &vec_y, RTLIL::Cell *cell)
+	void extendSignalWidthUnary(std::vector<int> &vec_a, std::vector<int> &vec_y, RTLIL::Cell *cell, bool undef_mode = false)
 	{
-		bool is_signed = cell->parameters.count("\\A_SIGNED") > 0 && cell->parameters["\\A_SIGNED"].as_bool();
+		assert(!undef_mode || model_undef);
+		bool is_signed = undef_mode || (cell->parameters.count("\\A_SIGNED") > 0 && cell->parameters["\\A_SIGNED"].as_bool());
 		while (vec_a.size() < vec_y.size())
 			vec_a.push_back(is_signed && vec_a.size() > 0 ? vec_a.back() : ez->FALSE);
 		while (vec_y.size() < vec_a.size())
@@ -103,9 +119,37 @@ struct SatGen
 
 	bool importCell(RTLIL::Cell *cell, int timestep = -1)
 	{
+		bool arith_undef_handled = false;
+		bool is_compare = cell->type == "$lt" || cell->type == "$le" || cell->type == "$eq" || cell->type == "$ne" || cell->type == "$ge" || cell->type == "$gt";
+
+		if (model_undef && (cell->type == "$add" || cell->type == "$sub" || cell->type == "$mul" || cell->type == "$div" || cell->type == "$mod" || is_compare))
+		{
+			std::vector<int> undef_a = importUndefSigSpec(cell->connections.at("\\A"), timestep);
+			std::vector<int> undef_b = importUndefSigSpec(cell->connections.at("\\B"), timestep);
+			std::vector<int> undef_y = importUndefSigSpec(cell->connections.at("\\Y"), timestep);
+			if (is_compare)
+				extendSignalWidth(undef_a, undef_b, cell, true);
+			else
+				extendSignalWidth(undef_a, undef_b, undef_y, cell, true);
+
+			int undef_any_a = ez->expression(ezSAT::OpOr, undef_a);
+			int undef_any_b = ez->expression(ezSAT::OpOr, undef_b);
+			int undef_y_bit = ez->OR(undef_any_a, undef_any_b);
+
+			if (cell->type == "$div" || cell->type == "$mod") {
+				std::vector<int> b = importSigSpec(cell->connections.at("\\B"), timestep);
+				undef_y_bit = ez->OR(undef_y_bit, ez->NOT(ez->expression(ezSAT::OpOr, b)));
+			}
+
+			std::vector<int> undef_y_bits(undef_y.size(), undef_y_bit);
+			ez->assume(ez->vec_eq(undef_y_bits, undef_y));
+			arith_undef_handled = true;
+		}
+
 		if (cell->type == "$_AND_" || cell->type == "$_OR_" || cell->type == "$_XOR_" ||
 				cell->type == "$and" || cell->type == "$or" || cell->type == "$xor" || cell->type == "$xnor" ||
-				cell->type == "$add" || cell->type == "$sub") {
+				cell->type == "$add" || cell->type == "$sub")
+		{
 			std::vector<int> a = importSigSpec(cell->connections.at("\\A"), timestep);
 			std::vector<int> b = importSigSpec(cell->connections.at("\\B"), timestep);
 			std::vector<int> y = importSigSpec(cell->connections.at("\\Y"), timestep);
@@ -122,27 +166,75 @@ struct SatGen
 				ez->assume(ez->vec_eq(ez->vec_add(a, b), y));
 			if (cell->type == "$sub")
 				ez->assume(ez->vec_eq(ez->vec_sub(a, b), y));
+
+			if (model_undef && !arith_undef_handled)
+			{
+				std::vector<int> undef_a = importUndefSigSpec(cell->connections.at("\\A"), timestep);
+				std::vector<int> undef_b = importUndefSigSpec(cell->connections.at("\\B"), timestep);
+				std::vector<int> undef_y = importUndefSigSpec(cell->connections.at("\\Y"), timestep);
+				extendSignalWidth(undef_a, undef_b, undef_y, cell, true);
+
+				if (cell->type == "$and" || cell->type == "$_AND_") {
+					std::vector<int> a0 = ez->vec_and(ez->vec_not(a), ez->vec_not(undef_a));
+					std::vector<int> b0 = ez->vec_and(ez->vec_not(b), ez->vec_not(undef_b));
+					std::vector<int> yX = ez->vec_and(ez->vec_or(undef_a, undef_b), ez->vec_not(ez->vec_or(a0, b0)));
+					ez->assume(ez->vec_eq(yX, undef_y));
+				}
+				else if (cell->type == "$or" || cell->type == "$_OR_") {
+					std::vector<int> a1 = ez->vec_and(a, ez->vec_not(undef_a));
+					std::vector<int> b1 = ez->vec_and(b, ez->vec_not(undef_b));
+					std::vector<int> yX = ez->vec_and(ez->vec_or(undef_a, undef_b), ez->vec_not(ez->vec_or(a1, b1)));
+					ez->assume(ez->vec_eq(yX, undef_y));
+				}
+				else /* xor, xnor */ {
+					std::vector<int> yX = ez->vec_or(undef_a, undef_b);
+					ez->assume(ez->vec_eq(yX, undef_y));
+				}
+			}
 			return true;
 		}
 
-		if (cell->type == "$_INV_" || cell->type == "$not") {
+		if (cell->type == "$_INV_" || cell->type == "$not")
+		{
 			std::vector<int> a = importSigSpec(cell->connections.at("\\A"), timestep);
 			std::vector<int> y = importSigSpec(cell->connections.at("\\Y"), timestep);
 			extendSignalWidthUnary(a, y, cell);
 			ez->assume(ez->vec_eq(ez->vec_not(a), y));
+
+			if (model_undef) {
+				std::vector<int> undef_a = importUndefSigSpec(cell->connections.at("\\A"), timestep);
+				std::vector<int> undef_y = importUndefSigSpec(cell->connections.at("\\Y"), timestep);
+				extendSignalWidthUnary(undef_a, undef_y, cell, true);
+				ez->assume(ez->vec_eq(undef_a, undef_y));
+			}
 			return true;
 		}
 
-		if (cell->type == "$_MUX_" || cell->type == "$mux") {
+		if (cell->type == "$_MUX_" || cell->type == "$mux")
+		{
 			std::vector<int> a = importSigSpec(cell->connections.at("\\A"), timestep);
 			std::vector<int> b = importSigSpec(cell->connections.at("\\B"), timestep);
 			std::vector<int> s = importSigSpec(cell->connections.at("\\S"), timestep);
 			std::vector<int> y = importSigSpec(cell->connections.at("\\Y"), timestep);
 			ez->assume(ez->vec_eq(ez->vec_ite(s.at(0), b, a), y));
+
+			if (model_undef)
+			{
+				std::vector<int> undef_a = importUndefSigSpec(cell->connections.at("\\A"), timestep);
+				std::vector<int> undef_b = importUndefSigSpec(cell->connections.at("\\B"), timestep);
+				std::vector<int> undef_s = importUndefSigSpec(cell->connections.at("\\S"), timestep);
+				std::vector<int> undef_y = importUndefSigSpec(cell->connections.at("\\Y"), timestep);
+
+				std::vector<int> unequal_ab = ez->vec_not(ez->vec_iff(a, b));
+				std::vector<int> undef_ab = ez->vec_or(unequal_ab, ez->vec_or(undef_a, undef_b));
+				std::vector<int> yX = ez->vec_ite(undef_s.at(0), undef_ab, ez->vec_ite(s.at(0), undef_b, undef_a));
+				ez->assume(ez->vec_eq(yX, undef_y));
+			}
 			return true;
 		}
 
-		if (cell->type == "$pmux" || cell->type == "$safe_pmux") {
+		if (cell->type == "$pmux" || cell->type == "$safe_pmux")
+		{
 			std::vector<int> a = importSigSpec(cell->connections.at("\\A"), timestep);
 			std::vector<int> b = importSigSpec(cell->connections.at("\\B"), timestep);
 			std::vector<int> s = importSigSpec(cell->connections.at("\\S"), timestep);
@@ -155,24 +247,48 @@ struct SatGen
 			if (cell->type == "$safe_pmux")
 				tmp = ez->vec_ite(ez->onehot(s, true), tmp, a);
 			ez->assume(ez->vec_eq(tmp, y));
+
+			if (model_undef) {
+				log("FIXME: No SAT undef model cell type %s!\n", RTLIL::id2cstr(cell->type));
+				std::vector<int> undef_y = importUndefSigSpec(cell->connections.at("\\Y"), timestep);
+				ez->assume(ez->NOT(ez->expression(ezSAT::OpOr, undef_y)));
+			}
 			return true;
 		}
 
-		if (cell->type == "$pos" || cell->type == "$neg") {
+		if (cell->type == "$pos" || cell->type == "$neg")
+		{
 			std::vector<int> a = importSigSpec(cell->connections.at("\\A"), timestep);
 			std::vector<int> y = importSigSpec(cell->connections.at("\\Y"), timestep);
 			extendSignalWidthUnary(a, y, cell);
+
 			if (cell->type == "$pos") {
 				ez->assume(ez->vec_eq(a, y));
 			} else {
 				std::vector<int> zero(a.size(), ez->FALSE);
 				ez->assume(ez->vec_eq(ez->vec_sub(zero, a), y));
 			}
+
+			if (model_undef)
+			{
+				std::vector<int> undef_a = importUndefSigSpec(cell->connections.at("\\A"), timestep);
+				std::vector<int> undef_y = importUndefSigSpec(cell->connections.at("\\Y"), timestep);
+				extendSignalWidthUnary(undef_a, undef_y, cell, true);
+
+				if (cell->type == "$pos") {
+					ez->assume(ez->vec_eq(undef_a, undef_y));
+				} else {
+					log("FIXME: No SAT undef model cell type %s!\n", RTLIL::id2cstr(cell->type));
+					std::vector<int> undef_y = importUndefSigSpec(cell->connections.at("\\Y"), timestep);
+					ez->assume(ez->NOT(ez->expression(ezSAT::OpOr, undef_y)));
+				}
+			}
 			return true;
 		}
 
 		if (cell->type == "$reduce_and" || cell->type == "$reduce_or" || cell->type == "$reduce_xor" ||
-				cell->type == "$reduce_xnor" || cell->type == "$reduce_bool" || cell->type == "$logic_not") {
+				cell->type == "$reduce_xnor" || cell->type == "$reduce_bool" || cell->type == "$logic_not")
+		{
 			std::vector<int> a = importSigSpec(cell->connections.at("\\A"), timestep);
 			std::vector<int> y = importSigSpec(cell->connections.at("\\Y"), timestep);
 			if (cell->type == "$reduce_and")
@@ -187,10 +303,17 @@ struct SatGen
 				ez->SET(ez->NOT(ez->expression(ez->OpOr, a)), y.at(0));
 			for (size_t i = 1; i < y.size(); i++)
 				ez->SET(ez->FALSE, y.at(i));
+
+			if (model_undef) {
+				log("FIXME: No SAT undef model cell type %s!\n", RTLIL::id2cstr(cell->type));
+				std::vector<int> undef_y = importUndefSigSpec(cell->connections.at("\\Y"), timestep);
+				ez->assume(ez->NOT(ez->expression(ezSAT::OpOr, undef_y)));
+			}
 			return true;
 		}
 
-		if (cell->type == "$logic_and" || cell->type == "$logic_or") {
+		if (cell->type == "$logic_and" || cell->type == "$logic_or")
+		{
 			int a = ez->expression(ez->OpOr, importSigSpec(cell->connections.at("\\A"), timestep));
 			int b = ez->expression(ez->OpOr, importSigSpec(cell->connections.at("\\B"), timestep));
 			std::vector<int> y = importSigSpec(cell->connections.at("\\Y"), timestep);
@@ -200,10 +323,17 @@ struct SatGen
 				ez->SET(ez->expression(ez->OpOr, a, b), y.at(0));
 			for (size_t i = 1; i < y.size(); i++)
 				ez->SET(ez->FALSE, y.at(i));
+
+			if (model_undef) {
+				log("FIXME: No SAT undef model cell type %s!\n", RTLIL::id2cstr(cell->type));
+				std::vector<int> undef_y = importUndefSigSpec(cell->connections.at("\\Y"), timestep);
+				ez->assume(ez->NOT(ez->expression(ezSAT::OpOr, undef_y)));
+			}
 			return true;
 		}
 
-		if (cell->type == "$lt" || cell->type == "$le" || cell->type == "$eq" || cell->type == "$ne" || cell->type == "$ge" || cell->type == "$gt") {
+		if (cell->type == "$lt" || cell->type == "$le" || cell->type == "$eq" || cell->type == "$ne" || cell->type == "$ge" || cell->type == "$gt")
+		{
 			bool is_signed = cell->parameters["\\A_SIGNED"].as_bool() && cell->parameters["\\B_SIGNED"].as_bool();
 			std::vector<int> a = importSigSpec(cell->connections.at("\\A"), timestep);
 			std::vector<int> b = importSigSpec(cell->connections.at("\\B"), timestep);
@@ -223,10 +353,12 @@ struct SatGen
 				ez->SET(is_signed ? ez->vec_gt_signed(a, b) : ez->vec_gt_unsigned(a, b), y.at(0));
 			for (size_t i = 1; i < y.size(); i++)
 				ez->SET(ez->FALSE, y.at(i));
+			assert(!model_undef || arith_undef_handled);
 			return true;
 		}
 
-		if (cell->type == "$shl" || cell->type == "$shr" || cell->type == "$sshl" || cell->type == "$sshr") {
+		if (cell->type == "$shl" || cell->type == "$shr" || cell->type == "$sshl" || cell->type == "$sshr")
+		{
 			std::vector<int> a = importSigSpec(cell->connections.at("\\A"), timestep);
 			std::vector<int> b = importSigSpec(cell->connections.at("\\B"), timestep);
 			std::vector<int> y = importSigSpec(cell->connections.at("\\Y"), timestep);
@@ -247,6 +379,12 @@ struct SatGen
 				tmp = ez->vec_ite(b.at(i), tmp_shifted, tmp);
 			}
 			ez->assume(ez->vec_eq(tmp, y));
+
+			if (model_undef) {
+				log("FIXME: No SAT undef model cell type %s!\n", RTLIL::id2cstr(cell->type));
+				std::vector<int> undef_y = importUndefSigSpec(cell->connections.at("\\Y"), timestep);
+				ez->assume(ez->NOT(ez->expression(ezSAT::OpOr, undef_y)));
+			}
 			return true;
 		}
 
@@ -264,6 +402,7 @@ struct SatGen
 				tmp = ez->vec_ite(b.at(i), ez->vec_add(tmp, shifted_a), tmp);
 			}
 			ez->assume(ez->vec_eq(tmp, y));
+			assert(!model_undef || arith_undef_handled);
 			return true;
 		}
 
@@ -337,10 +476,12 @@ struct SatGen
 				ez->assume(ez->vec_eq(y, ez->vec_ite(ez->expression(ezSAT::OpOr, b), y_tmp, div_zero_result)));
 			}
 
+			assert(!model_undef || arith_undef_handled);
 			return true;
 		}
 
-		if (timestep > 0 && (cell->type == "$dff" || cell->type == "$_DFF_N_" || cell->type == "$_DFF_P_")) {
+		if (timestep > 0 && (cell->type == "$dff" || cell->type == "$_DFF_N_" || cell->type == "$_DFF_P_"))
+		{
 			if (timestep == 1) {
 				initial_state.add((*sigmap)(cell->connections.at("\\Q")));
 			} else {
@@ -348,10 +489,16 @@ struct SatGen
 				std::vector<int> q = importSigSpec(cell->connections.at("\\Q"), timestep);
 				ez->assume(ez->vec_eq(d, q));
 			}
+
+			if (model_undef) {
+				log("FIXME: No SAT undef model cell type %s!\n", RTLIL::id2cstr(cell->type));
+				std::vector<int> undef_y = importUndefSigSpec(cell->connections.at("\\Y"), timestep);
+				ez->assume(ez->NOT(ez->expression(ezSAT::OpOr, undef_y)));
+			}
 			return true;
 		}
 
-		// Unsupported internal cell types: $div $mod $pow
+		// Unsupported internal cell types: $pow $lut
 		// .. and all sequential cells except $dff and $_DFF_[NP]_
 		return false;
 	}