Add "buffered-normalized mode", add $buf cell type, and add "bufnorm" command

backends/rtlil/rtlil_backend.cc

@@ -125,6 +125,10 @@ void RTLIL_BACKEND::dump_wire(std::ostream &f, std::string indent, const RTLIL::
 		dump_const(f, it.second);
 		f << stringf("\n");
 	}
+	if (wire->driverCell_) {
+		f << stringf("%s" "# driver %s %s\n", indent.c_str(),
+				wire->driverCell()->name.c_str(), wire->driverPort().c_str());
+	}
 	f << stringf("%s" "wire ", indent.c_str());
 	if (wire->width != 1)
 		f << stringf("width %d ", wire->width);

kernel/calc.cc

@@ -601,6 +601,14 @@ RTLIL::Const RTLIL::const_pos(const RTLIL::Const &arg1, const RTLIL::Const&, boo
 	return arg1_ext;
 }
 
+RTLIL::Const RTLIL::const_buf(const RTLIL::Const &arg1, const RTLIL::Const&, bool signed1, bool, int result_len)
+{
+	RTLIL::Const arg1_ext = arg1;
+	extend_u0(arg1_ext, result_len, signed1);
+
+	return arg1_ext;
+}
+
 RTLIL::Const RTLIL::const_neg(const RTLIL::Const &arg1, const RTLIL::Const&, bool signed1, bool, int result_len)
 {
 	RTLIL::Const arg1_ext = arg1;

kernel/cellaigs.cc

@@ -290,7 +290,7 @@ Aig::Aig(Cell *cell)
 		}
 	}
 
-	if (cell->type.in(ID($not), ID($_NOT_), ID($pos), ID($_BUF_)))
+	if (cell->type.in(ID($not), ID($_NOT_), ID($pos), ID($buf), ID($_BUF_)))
 	{
 		for (int i = 0; i < GetSize(cell->getPort(ID::Y)); i++) {
 			int A = mk.inport(ID::A, i);

kernel/celledges.cc

@@ -24,7 +24,7 @@ PRIVATE_NAMESPACE_BEGIN
 
 void bitwise_unary_op(AbstractCellEdgesDatabase *db, RTLIL::Cell *cell)
 {
-	bool is_signed = cell->getParam(ID::A_SIGNED).as_bool();
+	bool is_signed = (cell->type != ID($buf)) && cell->getParam(ID::A_SIGNED).as_bool();
 	int a_width = GetSize(cell->getPort(ID::A));
 	int y_width = GetSize(cell->getPort(ID::Y));
 
@@ -392,7 +392,7 @@ PRIVATE_NAMESPACE_END
 
 bool YOSYS_NAMESPACE_PREFIX AbstractCellEdgesDatabase::add_edges_from_cell(RTLIL::Cell *cell)
 {
-	if (cell->type.in(ID($not), ID($pos))) {
+	if (cell->type.in(ID($not), ID($pos), ID($buf))) {
 		bitwise_unary_op(this, cell);
 		return true;
 	}

kernel/celltypes.h

@@ -114,7 +114,7 @@ struct CellTypes
 	void setup_internals_eval()
 	{
 		std::vector<RTLIL::IdString> unary_ops = {
-			ID($not), ID($pos), ID($neg),
+			ID($not), ID($pos), ID($buf), ID($neg),
 			ID($reduce_and), ID($reduce_or), ID($reduce_xor), ID($reduce_xnor), ID($reduce_bool),
 			ID($logic_not), ID($slice), ID($lut), ID($sop)
 		};
@@ -339,7 +339,7 @@ struct CellTypes
 			type = ID($shl);
 
 		if (type != ID($sshr) && type != ID($sshl) && type != ID($shr) && type != ID($shl) && type != ID($shift) && type != ID($shiftx) &&
-				type != ID($pos) && type != ID($neg) && type != ID($not)) {
+				type != ID($pos) && type != ID($buf) && type != ID($neg) && type != ID($not)) {
 			if (!signed1 || !signed2)
 				signed1 = false, signed2 = false;
 		}
@@ -381,6 +381,7 @@ struct CellTypes
 		HANDLE_CELL_TYPE(modfloor)
 		HANDLE_CELL_TYPE(pow)
 		HANDLE_CELL_TYPE(pos)
+		HANDLE_CELL_TYPE(buf)
 		HANDLE_CELL_TYPE(neg)
 #undef HANDLE_CELL_TYPE
 

kernel/constids.inc

@@ -43,6 +43,7 @@ X(CE_OVER_SRST)
 X(CFG_ABITS)
 X(CFG_DBITS)
 X(CFG_INIT)
+X(chain)
 X(CI)
 X(CLK)
 X(clkbuf_driver)

kernel/qcsat.cc

@@ -77,7 +77,7 @@ void QuickConeSat::prepare()
 
 int QuickConeSat::cell_complexity(RTLIL::Cell *cell)
 {
-	if (cell->type.in(ID($concat), ID($slice), ID($pos), ID($_BUF_)))
+	if (cell->type.in(ID($concat), ID($slice), ID($pos), ID($buf), ID($_BUF_)))
 		return 0;
 	if (cell->type.in(ID($not), ID($and), ID($or), ID($xor), ID($xnor),
 			ID($reduce_and), ID($reduce_or), ID($reduce_xor),

kernel/rtlil.cc

@@ -21,6 +21,7 @@
 #include "kernel/macc.h"
 #include "kernel/celltypes.h"
 #include "kernel/binding.h"
+#include "kernel/sigtools.h"
 #include "frontends/verilog/verilog_frontend.h"
 #include "frontends/verilog/preproc.h"
 #include "backends/rtlil/rtlil_backend.h"
@@ -1108,6 +1109,13 @@ namespace {
 					cell->type.begins_with("$verific$") || cell->type.begins_with("$array:") || cell->type.begins_with("$extern:"))
 				return;
 
+			if (cell->type == ID($buf)) {
+				port(ID::A, param(ID::WIDTH));
+				port(ID::Y, param(ID::WIDTH));
+				check_expected();
+				return;
+			}
+
 			if (cell->type.in(ID($not), ID($pos), ID($neg))) {
 				param_bool(ID::A_SIGNED);
 				port(ID::A, param(ID::A_WIDTH));
@@ -2493,6 +2501,23 @@ DEF_METHOD(ReduceBool, 1, ID($reduce_bool))
 DEF_METHOD(LogicNot,   1, ID($logic_not))
 #undef DEF_METHOD
 
+#define DEF_METHOD(_func, _y_size, _type) \
+	RTLIL::Cell* RTLIL::Module::add ## _func(RTLIL::IdString name, const RTLIL::SigSpec &sig_a, const RTLIL::SigSpec &sig_y, bool /* is_signed */, const std::string &src) { \
+		RTLIL::Cell *cell = addCell(name, _type);           \
+		cell->parameters[ID::WIDTH] = sig_a.size();         \
+		cell->setPort(ID::A, sig_a);                        \
+		cell->setPort(ID::Y, sig_y);                        \
+		cell->set_src_attribute(src);                       \
+		return cell;                                        \
+	} \
+	RTLIL::SigSpec RTLIL::Module::_func(RTLIL::IdString name, const RTLIL::SigSpec &sig_a, bool is_signed, const std::string &src) { \
+		RTLIL::SigSpec sig_y = addWire(NEW_ID, _y_size);    \
+		add ## _func(name, sig_a, sig_y, is_signed, src);   \
+		return sig_y;                                       \
+	}
+DEF_METHOD(Buf, sig_a.size(), ID($buf))
+#undef DEF_METHOD
+
 #define DEF_METHOD(_func, _y_size, _type) \
 	RTLIL::Cell* RTLIL::Module::add ## _func(RTLIL::IdString name, const RTLIL::SigSpec &sig_a, const RTLIL::SigSpec &sig_b, const RTLIL::SigSpec &sig_y, bool is_signed, const std::string &src) { \
 		RTLIL::Cell *cell = addCell(name, _type);           \
@@ -3540,6 +3565,110 @@ void RTLIL::Cell::unsetPort(const RTLIL::IdString& portname)
 	}
 }
 
+void RTLIL::Design::bufNormalize(bool enable)
+{
+	if (!enable)
+	{
+		if (!flagBufferedNormalized)
+			return;
+
+		for (auto module : modules()) {
+			module->bufNormQueue.clear();
+			for (auto wire : module->wires()) {
+				wire->driverCell_ = nullptr;
+				wire->driverPort_ = IdString();
+			}
+		}
+
+		flagBufferedNormalized = false;
+		return;
+	}
+
+	if (!flagBufferedNormalized)
+	{
+		for (auto module : modules())
+		{
+			for (auto cell : module->cells())
+			for (auto &conn : cell->connections()) {
+				if (!cell->output(conn.first) || GetSize(conn.second) == 0)
+					continue;
+				if (conn.second.is_wire()) {
+					Wire *wire = conn.second.as_wire();
+					log_assert(wire->driverCell_ == nullptr);
+					wire->driverCell_ = cell;
+					wire->driverPort_ = conn.first;
+				} else {
+					pair<RTLIL::Cell*, RTLIL::IdString> key(cell, conn.first);
+					module->bufNormQueue.insert(key);
+				}
+			}
+		}
+
+		flagBufferedNormalized = true;
+	}
+
+	for (auto module : modules())
+		module->bufNormalize();
+}
+
+void RTLIL::Module::bufNormalize()
+{
+	if (!design->flagBufferedNormalized)
+		return;
+
+	while (GetSize(bufNormQueue) || !connections_.empty())
+	{
+		pool<pair<RTLIL::Cell*, RTLIL::IdString>> queue;
+		bufNormQueue.swap(queue);
+
+		pool<Wire*> outWires;
+		for (auto &conn : connections())
+		for (auto &chunk : conn.first.chunks())
+			if (chunk.wire) outWires.insert(chunk.wire);
+
+		SigMap sigmap(this);
+		new_connections({});
+
+		for (auto &key : queue)
+		{
+			Cell *cell = key.first;
+			const IdString &portname = key.second;
+			const SigSpec &sig = cell->getPort(portname);
+			if (GetSize(sig) == 0) continue;
+
+			if (sig.is_wire()) {
+				Wire *wire = sig.as_wire();
+				if (wire->driverCell_) {
+					log_error("Conflict between %s %s in module %s\n",
+										log_id(cell), log_id(wire->driverCell_), log_id(this));
+				}
+				log_assert(wire->driverCell_ == nullptr);
+				wire->driverCell_ = cell;
+				wire->driverPort_ = portname;
+				continue;
+			}
+
+			for (auto &chunk : sig.chunks())
+				if (chunk.wire) outWires.insert(chunk.wire);
+
+			Wire *wire = addWire(NEW_ID, GetSize(sig));
+			sigmap.add(sig, wire);
+			cell->setPort(portname, wire);
+
+			// FIXME: Move init attributes from old 'sig' to new 'wire'
+		}
+
+		for (auto wire : outWires)
+		{
+			SigSpec outsig = wire, insig = sigmap(wire);
+			for (int i = 0; i < GetSize(wire); i++)
+				if (insig[i] == outsig[i])
+					insig[i] = State::Sx;
+			addBuf(NEW_ID, insig, outsig);
+		}
+	}
+}
+
 void RTLIL::Cell::setPort(const RTLIL::IdString& portname, RTLIL::SigSpec signal)
 {
 	auto r = connections_.insert(portname);
@@ -3559,6 +3688,40 @@ void RTLIL::Cell::setPort(const RTLIL::IdString& portname, RTLIL::SigSpec signal
 		log_backtrace("-X- ", yosys_xtrace-1);
 	}
 
+	while (module->design && module->design->flagBufferedNormalized && output(portname))
+	{
+		pair<RTLIL::Cell*, RTLIL::IdString> key(this, portname);
+
+		if (conn_it->second.is_wire()) {
+			Wire *w = conn_it->second.as_wire();
+			if (w->driverCell_ == this && w->driverPort_ == portname) {
+				w->driverCell_ = nullptr;
+				w->driverPort_ = IdString();
+			}
+		}
+
+		if (GetSize(signal) == 0) {
+			module->bufNormQueue.erase(key);
+			break;
+		}
+
+		if (!signal.is_wire()) {
+			module->bufNormQueue.insert(key);
+			break;
+		}
+
+		Wire *w = signal.as_wire();
+		if (w->driverCell_ != nullptr) {
+			pair<RTLIL::Cell*, RTLIL::IdString> other_key(w->driverCell_, w->driverPort_);
+			module->bufNormQueue.insert(other_key);
+		}
+		w->driverCell_ = this;
+		w->driverPort_ = portname;
+
+		module->bufNormQueue.erase(key);
+		break;
+	}
+
 	conn_it->second = std::move(signal);
 }
 
@@ -3654,9 +3817,9 @@ void RTLIL::Cell::fixup_parameters(bool set_a_signed, bool set_b_signed)
 			type.begins_with("$verific$") || type.begins_with("$array:") || type.begins_with("$extern:"))
 		return;
 
-	if (type == ID($mux) || type == ID($pmux) || type == ID($bmux)) {
+	if (type == ID($buf) || type == ID($mux) || type == ID($pmux) || type == ID($bmux)) {
 		parameters[ID::WIDTH] = GetSize(connections_[ID::Y]);
-		if (type != ID($mux))
+		if (type != ID($buf) && type != ID($mux))
 			parameters[ID::S_WIDTH] = GetSize(connections_[ID::S]);
 		check();
 		return;

kernel/rtlil.h

@@ -503,6 +503,7 @@ namespace RTLIL
 	RTLIL::Const const_pow         (const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len);
 
 	RTLIL::Const const_pos         (const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len);
+	RTLIL::Const const_buf         (const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len);
 	RTLIL::Const const_neg         (const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len);
 
 	RTLIL::Const const_mux         (const RTLIL::Const &arg1, const RTLIL::Const &arg2, const RTLIL::Const &arg3);
@@ -1065,6 +1066,9 @@ struct RTLIL::Design
 	pool<RTLIL::Monitor*> monitors;
 	dict<std::string, std::string> scratchpad;
 
+	bool flagBufferedNormalized = false;
+	void bufNormalize(bool enable=true);
+
 	int refcount_modules_;
 	dict<RTLIL::IdString, RTLIL::Module*> modules_;
 	std::vector<RTLIL::Binding*> bindings_;
@@ -1209,6 +1213,9 @@ struct RTLIL::Module : public RTLIL::AttrObject
 	std::vector<RTLIL::IdString> ports;
 	void fixup_ports();
 
+	pool<pair<RTLIL::Cell*, RTLIL::IdString>> bufNormQueue;
+	void bufNormalize();
+
 	template<typename T> void rewrite_sigspecs(T &functor);
 	template<typename T> void rewrite_sigspecs2(T &functor);
 	void cloneInto(RTLIL::Module *new_mod) const;
@@ -1280,6 +1287,7 @@ struct RTLIL::Module : public RTLIL::AttrObject
 
 	RTLIL::Cell* addNot (RTLIL::IdString name, const RTLIL::SigSpec &sig_a, const RTLIL::SigSpec &sig_y, bool is_signed = false, const std::string &src = "");
 	RTLIL::Cell* addPos (RTLIL::IdString name, const RTLIL::SigSpec &sig_a, const RTLIL::SigSpec &sig_y, bool is_signed = false, const std::string &src = "");
+	RTLIL::Cell* addBuf (RTLIL::IdString name, const RTLIL::SigSpec &sig_a, const RTLIL::SigSpec &sig_y, bool is_signed = false, const std::string &src = "");
 	RTLIL::Cell* addNeg (RTLIL::IdString name, const RTLIL::SigSpec &sig_a, const RTLIL::SigSpec &sig_y, bool is_signed = false, const std::string &src = "");
 
 	RTLIL::Cell* addAnd  (RTLIL::IdString name, const RTLIL::SigSpec &sig_a, const RTLIL::SigSpec &sig_b, const RTLIL::SigSpec &sig_y, bool is_signed = false, const std::string &src = "");
@@ -1414,6 +1422,7 @@ struct RTLIL::Module : public RTLIL::AttrObject
 
 	RTLIL::SigSpec Not (RTLIL::IdString name, const RTLIL::SigSpec &sig_a, bool is_signed = false, const std::string &src = "");
 	RTLIL::SigSpec Pos (RTLIL::IdString name, const RTLIL::SigSpec &sig_a, bool is_signed = false, const std::string &src = "");
+	RTLIL::SigSpec Buf (RTLIL::IdString name, const RTLIL::SigSpec &sig_a, bool is_signed = false, const std::string &src = "");
 	RTLIL::SigSpec Neg (RTLIL::IdString name, const RTLIL::SigSpec &sig_a, bool is_signed = false, const std::string &src = "");
 
 	RTLIL::SigSpec And  (RTLIL::IdString name, const RTLIL::SigSpec &sig_a, const RTLIL::SigSpec &sig_b, bool is_signed = false, const std::string &src = "");
@@ -1501,6 +1510,10 @@ struct RTLIL::Module : public RTLIL::AttrObject
 #endif
 };
 
+namespace RTLIL_BACKEND {
+void dump_wire(std::ostream &f, std::string indent, const RTLIL::Wire *wire);
+}
+
 struct RTLIL::Wire : public RTLIL::AttrObject
 {
 	unsigned int hashidx_;
@@ -1512,6 +1525,12 @@ struct RTLIL::Wire : public RTLIL::AttrObject
 	Wire();
 	~Wire();
 
+	friend struct RTLIL::Design;
+	friend struct RTLIL::Cell;
+	friend void RTLIL_BACKEND::dump_wire(std::ostream &f, std::string indent, const RTLIL::Wire *wire);
+	RTLIL::Cell *driverCell_ = nullptr;
+	RTLIL::IdString driverPort_;
+
 public:
 	// do not simply copy wires
 	Wire(RTLIL::Wire &other) = delete;
@@ -1522,6 +1541,9 @@ struct RTLIL::Wire : public RTLIL::AttrObject
 	int width, start_offset, port_id;
 	bool port_input, port_output, upto, is_signed;
 
+	RTLIL::Cell *driverCell() const    { log_assert(driverCell_); return driverCell_; };
+	RTLIL::IdString driverPort() const { log_assert(driverCell_); return driverPort_; };
+
 #ifdef WITH_PYTHON
 	static std::map<unsigned int, RTLIL::Wire*> *get_all_wires(void);
 #endif