Add "read_verilog -pwires" feature

README.md

@@ -354,6 +354,10 @@ Verilog Attributes and non-standard features
   module inputs. The attribute is attached to the input wire by the HDL
   front-end when the input is declared with a default value.
 
+- The ``parameter`` and ``localparam`` attributes are used to mark wires
+  that represent module parameters or localparams (when the HDL front-end
+  is run in -pwires mode).
+
 - In addition to the ``(* ... *)`` attribute syntax, Yosys supports
   the non-standard ``{* ... *}`` attribute syntax to set default attributes
   for everything that comes after the ``{* ... *}`` statement. (Reset

frontends/ast/ast.cc

@@ -46,7 +46,7 @@ namespace AST {
 // instantiate global variables (private API)
 namespace AST_INTERNAL {
 	bool flag_dump_ast1, flag_dump_ast2, flag_no_dump_ptr, flag_dump_vlog1, flag_dump_vlog2, flag_dump_rtlil, flag_nolatches, flag_nomeminit;
-	bool flag_nomem2reg, flag_mem2reg, flag_noblackbox, flag_lib, flag_nowb, flag_noopt, flag_icells, flag_autowire;
+	bool flag_nomem2reg, flag_mem2reg, flag_noblackbox, flag_lib, flag_nowb, flag_noopt, flag_icells, flag_pwires, flag_autowire;
 	AstNode *current_ast, *current_ast_mod;
 	std::map<std::string, AstNode*> current_scope;
 	const dict<RTLIL::SigBit, RTLIL::SigBit> *genRTLIL_subst_ptr = NULL;
@@ -1112,6 +1112,7 @@ static AstModule* process_module(AstNode *ast, bool defer, AstNode *original_ast
 	current_module->nowb = flag_nowb;
 	current_module->noopt = flag_noopt;
 	current_module->icells = flag_icells;
+	current_module->pwires = flag_pwires;
 	current_module->autowire = flag_autowire;
 	current_module->fixup_ports();
 
@@ -1126,7 +1127,7 @@ static AstModule* process_module(AstNode *ast, bool defer, AstNode *original_ast
 
 // create AstModule instances for all modules in the AST tree and add them to 'design'
 void AST::process(RTLIL::Design *design, AstNode *ast, bool dump_ast1, bool dump_ast2, bool no_dump_ptr, bool dump_vlog1, bool dump_vlog2, bool dump_rtlil,
-		bool nolatches, bool nomeminit, bool nomem2reg, bool mem2reg, bool noblackbox, bool lib, bool nowb, bool noopt, bool icells, bool nooverwrite, bool overwrite, bool defer, bool autowire)
+		bool nolatches, bool nomeminit, bool nomem2reg, bool mem2reg, bool noblackbox, bool lib, bool nowb, bool noopt, bool icells, bool pwires, bool nooverwrite, bool overwrite, bool defer, bool autowire)
 {
 	current_ast = ast;
 	flag_dump_ast1 = dump_ast1;
@@ -1144,6 +1145,7 @@ void AST::process(RTLIL::Design *design, AstNode *ast, bool dump_ast1, bool dump
 	flag_nowb = nowb;
 	flag_noopt = noopt;
 	flag_icells = icells;
+	flag_pwires = pwires;
 	flag_autowire = autowire;
 
 	log_assert(current_ast->type == AST_DESIGN);
@@ -1480,6 +1482,7 @@ std::string AstModule::derive_common(RTLIL::Design *design, dict<RTLIL::IdString
 	flag_nowb = nowb;
 	flag_noopt = noopt;
 	flag_icells = icells;
+	flag_pwires = pwires;
 	flag_autowire = autowire;
 	use_internal_line_num();
 
@@ -1551,6 +1554,7 @@ RTLIL::Module *AstModule::clone() const
 	new_mod->lib = lib;
 	new_mod->noopt = noopt;
 	new_mod->icells = icells;
+	new_mod->pwires = pwires;
 	new_mod->autowire = autowire;
 
 	return new_mod;

frontends/ast/ast.h

@@ -286,13 +286,13 @@ namespace AST
 
 	// process an AST tree (ast must point to an AST_DESIGN node) and generate RTLIL code
 	void process(RTLIL::Design *design, AstNode *ast, bool dump_ast1, bool dump_ast2, bool no_dump_ptr, bool dump_vlog1, bool dump_vlog2, bool dump_rtlil, bool nolatches, bool nomeminit,
-			bool nomem2reg, bool mem2reg, bool noblackbox, bool lib, bool nowb, bool noopt, bool icells, bool nooverwrite, bool overwrite, bool defer, bool autowire);
+			bool nomem2reg, bool mem2reg, bool noblackbox, bool lib, bool nowb, bool noopt, bool icells, bool pwires, bool nooverwrite, bool overwrite, bool defer, bool autowire);
 
 	// parametric modules are supported directly by the AST library
 	// therefore we need our own derivate of RTLIL::Module with overloaded virtual functions
 	struct AstModule : RTLIL::Module {
 		AstNode *ast;
-		bool nolatches, nomeminit, nomem2reg, mem2reg, noblackbox, lib, nowb, noopt, icells, autowire;
+		bool nolatches, nomeminit, nomem2reg, mem2reg, noblackbox, lib, nowb, noopt, icells, pwires, autowire;
 		~AstModule() YS_OVERRIDE;
 		RTLIL::IdString derive(RTLIL::Design *design, dict<RTLIL::IdString, RTLIL::Const> parameters, bool mayfail) YS_OVERRIDE;
 		RTLIL::IdString derive(RTLIL::Design *design, dict<RTLIL::IdString, RTLIL::Const> parameters, dict<RTLIL::IdString, RTLIL::Module*> interfaces, dict<RTLIL::IdString, RTLIL::IdString> modports, bool mayfail) YS_OVERRIDE;
@@ -325,7 +325,7 @@ namespace AST_INTERNAL
 {
 	// internal state variables
 	extern bool flag_dump_ast1, flag_dump_ast2, flag_no_dump_ptr, flag_dump_rtlil, flag_nolatches, flag_nomeminit;
-	extern bool flag_nomem2reg, flag_mem2reg, flag_lib, flag_noopt, flag_icells, flag_autowire;
+	extern bool flag_nomem2reg, flag_mem2reg, flag_lib, flag_noopt, flag_icells, flag_pwires, flag_autowire;
 	extern AST::AstNode *current_ast, *current_ast_mod;
 	extern std::map<std::string, AST::AstNode*> current_scope;
 	extern const dict<RTLIL::SigBit, RTLIL::SigBit> *genRTLIL_subst_ptr;

frontends/ast/genrtlil.cc

@@ -853,7 +853,6 @@ RTLIL::SigSpec AstNode::genRTLIL(int width_hint, bool sign_hint)
 	case AST_FUNCTION:
 	case AST_DPI_FUNCTION:
 	case AST_AUTOWIRE:
-	case AST_LOCALPARAM:
 	case AST_DEFPARAM:
 	case AST_GENVAR:
 	case AST_GENFOR:
@@ -895,6 +894,26 @@ RTLIL::SigSpec AstNode::genRTLIL(int width_hint, bool sign_hint)
 	// remember the parameter, needed for example in techmap
 	case AST_PARAMETER:
 		current_module->avail_parameters.insert(str);
+		/* fall through */
+	case AST_LOCALPARAM:
+		if (flag_pwires)
+		{
+			if (GetSize(children) < 1 || children[0]->type != AST_CONSTANT)
+				log_file_error(filename, linenum, "Parameter `%s' with non-constant value!\n", str.c_str());
+
+			RTLIL::Const val = children[0]->bitsAsConst();
+			RTLIL::Wire *wire = current_module->addWire(str, GetSize(val));
+			current_module->connect(wire, val);
+
+			wire->attributes["\\src"] = stringf("%s:%d", filename.c_str(), linenum);
+			wire->attributes[type == AST_PARAMETER ? "\\parameter" : "\\localparam"] = 1;
+
+			for (auto &attr : attributes) {
+				if (attr.second->type != AST_CONSTANT)
+					log_file_error(filename, linenum, "Attribute `%s' with non-constant value!\n", attr.first.c_str());
+				wire->attributes[attr.first] = attr.second->asAttrConst();
+			}
+		}
 		break;
 
 	// create an RTLIL::Wire for an AST_WIRE node

frontends/verilog/verilog_frontend.cc

@@ -168,6 +168,9 @@ struct VerilogFrontend : public Frontend {
 		log("    -icells\n");
 		log("        interpret cell types starting with '$' as internal cell types\n");
 		log("\n");
+		log("    -pwires\n");
+		log("        add a wire for each module parameter\n");
+		log("\n");
 		log("    -nooverwrite\n");
 		log("        ignore re-definitions of modules. (the default behavior is to\n");
 		log("        create an error message if the existing module is not a black box\n");
@@ -228,6 +231,7 @@ struct VerilogFrontend : public Frontend {
 		bool flag_nodpi = false;
 		bool flag_noopt = false;
 		bool flag_icells = false;
+		bool flag_pwires = false;
 		bool flag_nooverwrite = false;
 		bool flag_overwrite = false;
 		bool flag_defer = false;
@@ -368,6 +372,10 @@ struct VerilogFrontend : public Frontend {
 				flag_icells = true;
 				continue;
 			}
+			if (arg == "-pwires") {
+				flag_pwires = true;
+				continue;
+			}
 			if (arg == "-ignore_redef" || arg == "-nooverwrite") {
 				flag_nooverwrite = true;
 				flag_overwrite = false;
@@ -458,7 +466,7 @@ struct VerilogFrontend : public Frontend {
 			error_on_dpi_function(current_ast);
 
 		AST::process(design, current_ast, flag_dump_ast1, flag_dump_ast2, flag_no_dump_ptr, flag_dump_vlog1, flag_dump_vlog2, flag_dump_rtlil, flag_nolatches,
-				flag_nomeminit, flag_nomem2reg, flag_mem2reg, flag_noblackbox, lib_mode, flag_nowb, flag_noopt, flag_icells, flag_nooverwrite, flag_overwrite, flag_defer, default_nettype_wire);
+				flag_nomeminit, flag_nomem2reg, flag_mem2reg, flag_noblackbox, lib_mode, flag_nowb, flag_noopt, flag_icells, flag_pwires, flag_nooverwrite, flag_overwrite, flag_defer, default_nettype_wire);
 
 		if (!flag_nopp)
 			delete lexin;

frontends/verilog/verilog_parser.y

@@ -319,15 +319,17 @@ module_para_list:
 
 single_module_para:
 	/* empty */ |
-	TOK_PARAMETER {
+	attr TOK_PARAMETER {
 		if (astbuf1) delete astbuf1;
 		astbuf1 = new AstNode(AST_PARAMETER);
 		astbuf1->children.push_back(AstNode::mkconst_int(0, true));
+		append_attr(astbuf1, $1);
 	} param_signed param_integer param_range single_param_decl |
-	TOK_LOCALPARAM {
+	attr TOK_LOCALPARAM {
 		if (astbuf1) delete astbuf1;
 		astbuf1 = new AstNode(AST_LOCALPARAM);
 		astbuf1->children.push_back(AstNode::mkconst_int(0, true));
+		append_attr(astbuf1, $1);
 	} param_signed param_integer param_range single_param_decl |
 	single_param_decl;
 
@@ -1217,6 +1219,7 @@ param_decl:
 	attr TOK_PARAMETER {
 		astbuf1 = new AstNode(AST_PARAMETER);
 		astbuf1->children.push_back(AstNode::mkconst_int(0, true));
+		append_attr(astbuf1, $1);
 	} param_signed param_integer param_real param_range param_decl_list ';' {
 		delete astbuf1;
 	};
@@ -1225,6 +1228,7 @@ localparam_decl:
 	attr TOK_LOCALPARAM {
 		astbuf1 = new AstNode(AST_LOCALPARAM);
 		astbuf1->children.push_back(AstNode::mkconst_int(0, true));
+		append_attr(astbuf1, $1);
 	} param_signed param_integer param_real param_range param_decl_list ';' {
 		delete astbuf1;
 	};