Add "read_ilang -[no]overwrite"

Signed-off-by: Clifford Wolf <clifford@clifford.at>

frontends/ilang/ilang_frontend.cc

@@ -44,11 +44,39 @@ struct IlangFrontend : public Frontend {
 		log("Load modules from an ilang file to the current design. (ilang is a text\n");
 		log("representation of a design in yosys's internal format.)\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 blackbox\n");
+		log("        module, and overwrite the existing module if it is  a blackbox module.)\n");
+		log("\n");
+		log("    -overwrite\n");
+		log("        overwrite existing modules with the same name\n");
+		log("\n");
 	}
 	void execute(std::istream *&f, std::string filename, std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
 	{
+		ILANG_FRONTEND::flag_nooverwrite = false;
+		ILANG_FRONTEND::flag_overwrite = false;
+
 		log_header(design, "Executing ILANG frontend.\n");
-		extra_args(f, filename, args, 1);
+
+		size_t argidx;
+		for (argidx = 1; argidx < args.size(); argidx++) {
+			std::string arg = args[argidx];
+			if (arg == "-nooverwrite") {
+				ILANG_FRONTEND::flag_nooverwrite = true;
+				ILANG_FRONTEND::flag_overwrite = false;
+				continue;
+			}
+			if (arg == "-overwrite") {
+				ILANG_FRONTEND::flag_nooverwrite = false;
+				ILANG_FRONTEND::flag_overwrite = true;
+				continue;
+			}
+			break;
+		}
+		extra_args(f, filename, args, argidx);
+
 		log("Input filename: %s\n", filename.c_str());
 
 		ILANG_FRONTEND::lexin = f;

frontends/ilang/ilang_frontend.h

@@ -32,6 +32,8 @@ YOSYS_NAMESPACE_BEGIN
 namespace ILANG_FRONTEND {
 	extern std::istream *lexin;
 	extern RTLIL::Design *current_design;
+	extern bool flag_nooverwrite;
+	extern bool flag_overwrite;
 }
 
 YOSYS_NAMESPACE_END

frontends/ilang/ilang_parser.y

@@ -37,6 +37,8 @@ namespace ILANG_FRONTEND {
 	std::vector<std::vector<RTLIL::SwitchRule*>*> switch_stack;
 	std::vector<RTLIL::CaseRule*> case_stack;
 	dict<RTLIL::IdString, RTLIL::Const> attrbuf;
+	bool flag_nooverwrite, flag_overwrite;
+	bool delete_current_module;
 }
 using namespace ILANG_FRONTEND;
 YOSYS_NAMESPACE_END
@@ -93,11 +95,26 @@ design:
 
 module:
 	TOK_MODULE TOK_ID EOL {
-		if (current_design->has($2))
+		delete_current_module = false;
+		if (current_design->has($2)) {
+			RTLIL::Module *existing_mod = current_design->module($2);
+			if (!flag_overwrite && attrbuf.count("\\blackbox") && attrbuf.at("\\blackbox").as_bool()) {
+				log("Ignoring blackbox re-definition of module %s.\n", $2);
+				delete_current_module = true;
+			} else if (!flag_nooverwrite && !flag_overwrite && !existing_mod->get_bool_attribute("\\blackbox")) {
 				rtlil_frontend_ilang_yyerror(stringf("ilang error: redefinition of module %s.", $2).c_str());
+			} else if (flag_nooverwrite) {
+				log("Ignoring re-definition of module %s.\n", $2);
+				delete_current_module = true;
+			} else {
+				log("Replacing existing%s module %s.\n", existing_mod->get_bool_attribute("\\blackbox") ? " blackbox" : "", $2);
+				current_design->remove(existing_mod);
+			}
+		}
 		current_module = new RTLIL::Module;
 		current_module->name = $2;
 		current_module->attributes = attrbuf;
+		if (!delete_current_module)
 			current_design->add(current_module);
 		attrbuf.clear();
 		free($2);
@@ -105,6 +122,9 @@ module:
 		if (attrbuf.size() != 0)
 			rtlil_frontend_ilang_yyerror("dangling attribute");
 		current_module->fixup_ports();
+		if (delete_current_module)
+			delete current_module;
+		current_module = nullptr;
 	} EOL;
 
 module_body: