yosys.patch

diff --git a/kernel/driver.cc b/kernel/driver.cc
index b55f0283..05987113 100644
--- a/kernel/driver.cc
+++ b/kernel/driver.cc
@@ -198,6 +198,7 @@ int main(int argc, char **argv)
 	std::string backend_command = "auto";
 	std::vector<std::string> vlog_defines;
 	std::vector<std::string> passes_commands;
+	std::vector<std::string> passes_commands_before;
 	std::vector<std::string> plugin_filenames;
 	std::string output_filename = "";
 	std::string scriptfile = "";
@@ -274,7 +275,10 @@ int main(int argc, char **argv)
 #endif
 		printf("\n");
 		printf("    -p command\n");
-		printf("        execute the commands\n");
+		printf("        execute the commands after input file processing\n");
+		printf("\n");
+		printf("    -Z command\n");
+		printf("        execute the commands before input file processing\n");
 		printf("\n");
 		printf("    -m module_file\n");
 		printf("        load the specified module (aka plugin)\n");
@@ -342,7 +346,7 @@ int main(int argc, char **argv)
 	}
 
 	int opt;
-	while ((opt = getopt(argc, argv, "MXAQTVSgm:f:Hh:b:o:p:l:L:qv:tds:c:W:w:e:r:D:P:E:x:")) != -1)
+	while ((opt = getopt(argc, argv, "MXAQTVSgm:f:Hh:b:o:p:Z:l:L:qv:tds:c:W:w:e:r:D:P:E:x:")) != -1)
 	{
 		switch (opt)
 		{
@@ -388,7 +392,11 @@ int main(int argc, char **argv)
 		case 'p':
 			passes_commands.push_back(optarg);
 			run_shell = false;
 			break;
+		case 'Z':
+			passes_commands_before.push_back(optarg);
+                       run_shell = false;
+			break;
 		case 'o':
 			output_filename = optarg;
 			run_shell = false;
@@ -519,6 +526,9 @@ int main(int argc, char **argv)
 		run_pass(vdef_cmd);
 	}
 
+	for (auto&& cmd : passes_commands_before)
+		run_pass(cmd);
+
 	while (optind < argc)
 		if (run_frontend(argv[optind++], frontend_command))
 			run_shell = false;