Implemented proper handling of stub placeholder modules

3 files changed, 30 insertions, 6 deletions

diff --git a/frontends/ast/ast.cc b/frontends/ast/ast.cc
index d35ea4171..091b196ef 100644
--- a/frontends/ast/ast.cc
+++ b/frontends/ast/ast.cc
@@ -46,7 +46,7 @@ namespace AST {
 
 // instanciate global variables (private API)
 namespace AST_INTERNAL {
-	bool flag_dump_ast, flag_dump_ast_diff, flag_dump_vlog, flag_nolatches, flag_nomem2reg, flag_mem2reg;
+	bool flag_dump_ast, flag_dump_ast_diff, flag_dump_vlog, flag_nolatches, flag_nomem2reg, flag_mem2reg, flag_lib;
 	AstNode *current_ast, *current_ast_mod;
 	std::map<std::string, AstNode*> current_scope;
 	RTLIL::SigSpec *genRTLIL_subst_from = NULL;
@@ -679,6 +679,18 @@ static AstModule* process_module(AstNode *ast)
 		log("--- END OF AST DUMP ---\n");
 	}
 
+	if (flag_lib) {
+		std::vector<AstNode*> new_children;
+		for (auto child : ast->children) {
+			if (child->type == AST_WIRE && (child->is_input || child->is_output))
+				new_children.push_back(child);
+			else
+				delete child;
+		}
+		ast->children.swap(new_children);
+		ast->attributes["\\placeholder"] = AstNode::mkconst_int(0, false, 0);
+	}
+
 	current_module = new AstModule;
 	current_module->ast = NULL;
 	current_module->name = ast->str;
@@ -705,11 +717,12 @@ static AstModule* process_module(AstNode *ast)
 	current_module->nolatches = flag_nolatches;
 	current_module->nomem2reg = flag_nomem2reg;
 	current_module->mem2reg = flag_mem2reg;
+	current_module->lib = flag_lib;
 	return current_module;
 }
 
 // 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_ast, bool dump_ast_diff, bool dump_vlog, bool nolatches, bool nomem2reg, bool mem2reg)
+void AST::process(RTLIL::Design *design, AstNode *ast, bool dump_ast, bool dump_ast_diff, bool dump_vlog, bool nolatches, bool nomem2reg, bool mem2reg, bool lib)
 {
 	current_ast = ast;
 	flag_dump_ast = dump_ast;
@@ -718,6 +731,7 @@ void AST::process(RTLIL::Design *design, AstNode *ast, bool dump_ast, bool dump_
 	flag_nolatches = nolatches;
 	flag_nomem2reg = nomem2reg;
 	flag_mem2reg = mem2reg;
+	flag_lib = lib;
 
 	assert(current_ast->type == AST_DESIGN);
 	for (auto it = current_ast->children.begin(); it != current_ast->children.end(); it++) {
@@ -747,6 +761,7 @@ RTLIL::IdString AstModule::derive(RTLIL::Design *design, std::map<RTLIL::IdStrin
 	flag_nolatches = nolatches;
 	flag_nomem2reg = nomem2reg;
 	flag_mem2reg = mem2reg;
+	flag_lib = lib;
 	use_internal_line_num();
 
 	std::vector<unsigned char> hash_data;
@@ -821,6 +836,7 @@ void AstModule::update_auto_wires(std::map<RTLIL::IdString, int> auto_sizes)
 	flag_nolatches = nolatches;
 	flag_nomem2reg = nomem2reg;
 	flag_mem2reg = mem2reg;
+	flag_lib = lib;
 	use_internal_line_num();
 
 	for (auto it = auto_sizes.begin(); it != auto_sizes.end(); it++) {
diff --git a/frontends/ast/ast.h b/frontends/ast/ast.h
index d65851acd..05b9a95cf 100644
--- a/frontends/ast/ast.h
+++ b/frontends/ast/ast.h
@@ -189,13 +189,13 @@ 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_ast = false, bool dump_ast_diff = false, bool dump_vlog = false, bool nolatches = false, bool nomem2reg = false, bool mem2reg = false);
+	void process(RTLIL::Design *design, AstNode *ast, bool dump_ast = false, bool dump_ast_diff = false, bool dump_vlog = false, bool nolatches = false, bool nomem2reg = false, bool mem2reg = false, bool lib = false);
 
 	// parametric modules are supported directly by the AST library
 	// therfore we need our own derivate of RTLIL::Module with overloaded virtual functions
 	struct AstModule : RTLIL::Module {
 		AstNode *ast;
-		bool nolatches, nomem2reg, mem2reg;
+		bool nolatches, nomem2reg, mem2reg, lib;
 		virtual ~AstModule();
 		virtual RTLIL::IdString derive(RTLIL::Design *design, std::map<RTLIL::IdString, RTLIL::Const> parameters);
 		virtual void update_auto_wires(std::map<RTLIL::IdString, int> auto_sizes);
@@ -217,7 +217,7 @@ namespace AST
 namespace AST_INTERNAL
 {
 	// internal state variables
-	extern bool flag_dump_ast, flag_dump_ast_diff, flag_nolatches, flag_nomem2reg, flag_mem2reg;
+	extern bool flag_dump_ast, flag_dump_ast_diff, flag_nolatches, flag_nomem2reg, flag_mem2reg, flag_lib;
 	extern AST::AstNode *current_ast, *current_ast_mod;
 	extern std::map<std::string, AST::AstNode*> current_scope;
 	extern RTLIL::SigSpec *genRTLIL_subst_from, *genRTLIL_subst_to;
diff --git a/frontends/verilog/verilog_frontend.cc b/frontends/verilog/verilog_frontend.cc
index f4a8c79fa..f9731cbc2 100644
--- a/frontends/verilog/verilog_frontend.cc
+++ b/frontends/verilog/verilog_frontend.cc
@@ -89,6 +89,9 @@ struct VerilogFrontend : public Frontend {
 		log("    -nopp\n");
 		log("        do not run the pre-processor\n");
 		log("\n");
+		log("    -lib\n");
+		log("        only create empty placeholder modules\n");
+		log("\n");
 	}
 	virtual void execute(FILE *&f, std::string filename, std::vector<std::string> args, RTLIL::Design *design)
 	{
@@ -100,6 +103,7 @@ struct VerilogFrontend : public Frontend {
 		bool flag_mem2reg = false;
 		bool flag_ppdump = false;
 		bool flag_nopp = false;
+		bool flag_lib = false;
 		frontend_verilog_yydebug = false;
 
 		log_header("Executing Verilog-2005 frontend.\n");
@@ -144,6 +148,10 @@ struct VerilogFrontend : public Frontend {
 				flag_nopp = true;
 				continue;
 			}
+			if (arg == "-lib") {
+				flag_lib = true;
+				continue;
+			}
 			break;
 		}
 		extra_args(f, filename, args, argidx);
@@ -173,7 +181,7 @@ struct VerilogFrontend : public Frontend {
 		frontend_verilog_yyparse();
 		frontend_verilog_yylex_destroy();
 
-		AST::process(design, current_ast, flag_dump_ast, flag_dump_ast_diff, flag_dump_vlog, flag_nolatches, flag_nomem2reg, flag_mem2reg);
+		AST::process(design, current_ast, flag_dump_ast, flag_dump_ast_diff, flag_dump_vlog, flag_nolatches, flag_nomem2reg, flag_mem2reg, flag_lib);
 
 		if (!flag_nopp)
 			fclose(fp);