1 files changed, 24 insertions, 4 deletions

diff --git a/passes/cmds/connect.cc b/passes/cmds/connect.cc
index 0cc6cbe52..d85ea9ad5 100644
--- a/passes/cmds/connect.cc
+++ b/passes/cmds/connect.cc
@@ -60,7 +60,7 @@ struct ConnectPass : public Pass {
 		log("Unconnect all existing drivers for the specified expression.\n");
 		log("\n");
 		log("\n");
-		log("    connect [-nomap] -port <cell> <port> <expr>\n");
+		log("    connect [-nomap] [-assert] -port <cell> <port> <expr>\n");
 		log("\n");
 		log("Connect the specified cell port to the specified cell port.\n");
 		log("\n");
@@ -72,6 +72,9 @@ struct ConnectPass : public Pass {
 		log("The connect command operates in one module only. Either only one module must\n");
 		log("be selected or an active module must be set using the 'cd' command.\n");
 		log("\n");
+		log("The -assert option verifies that the connection already exists, instead of\n");
+		log("making it.\n");
+		log("\n");
 		log("This command does not operate on module with processes.\n");
 		log("\n");
 	}
@@ -88,7 +91,7 @@ struct ConnectPass : public Pass {
 		if (!module->processes.empty())
 			log_cmd_error("Found processes in selected module.\n");
 
-		bool flag_nounset = false, flag_nomap = false;
+		bool flag_nounset = false, flag_nomap = false, flag_assert = false;
 		std::string set_lhs, set_rhs, unset_expr;
 		std::string port_cell, port_port, port_expr;
 
@@ -104,6 +107,10 @@ struct ConnectPass : public Pass {
 				flag_nomap = true;
 				continue;
 			}
+			if (arg == "-assert") {
+				flag_assert = true;
+				continue;
+			}
 			if (arg == "-set" && argidx+2 < args.size()) {
 				set_lhs = args[++argidx];
 				set_rhs = args[++argidx];
@@ -126,7 +133,7 @@ struct ConnectPass : public Pass {
 		if (!flag_nomap)
 			for (auto &it : module->connections()) {
 				std::vector<RTLIL::SigBit> lhs = it.first.to_sigbit_vector();
-				std::vector<RTLIL::SigBit> rhs = it.first.to_sigbit_vector();
+				std::vector<RTLIL::SigBit> rhs = it.second.to_sigbit_vector();
 				for (size_t i = 0; i < lhs.size(); i++)
 					if (rhs[i].wire != nullptr)
 						sigmap.add(lhs[i], rhs[i]);
@@ -137,6 +144,9 @@ struct ConnectPass : public Pass {
 			if (!unset_expr.empty() || !port_cell.empty())
 				log_cmd_error("Can't use -set together with -unset and/or -port.\n");
 
+			if (flag_assert)
+				log_cmd_error("The -assert option is only supported with -port.\n");
+
 			RTLIL::SigSpec sig_lhs, sig_rhs;
 			if (!RTLIL::SigSpec::parse_sel(sig_lhs, design, module, set_lhs))
 				log_cmd_error("Failed to parse set lhs expression `%s'.\n", set_lhs.c_str());
@@ -157,6 +167,9 @@ struct ConnectPass : public Pass {
 			if (!port_cell.empty() || flag_nounset)
 				log_cmd_error("Can't use -unset together with -port and/or -nounset.\n");
 
+			if (flag_assert)
+				log_cmd_error("The -assert option is only supported with -port.\n");
+
 			RTLIL::SigSpec sig;
 			if (!RTLIL::SigSpec::parse_sel(sig, design, module, unset_expr))
 				log_cmd_error("Failed to parse unset expression `%s'.\n", unset_expr.c_str());
@@ -177,7 +190,14 @@ struct ConnectPass : public Pass {
 			if (!RTLIL::SigSpec::parse_sel(sig, design, module, port_expr))
 				log_cmd_error("Failed to parse port expression `%s'.\n", port_expr.c_str());
 
-			module->cell(RTLIL::escape_id(port_cell))->setPort(RTLIL::escape_id(port_port), sigmap(sig));
+			if (!flag_assert) {
+				module->cell(RTLIL::escape_id(port_cell))->setPort(RTLIL::escape_id(port_port), sigmap(sig));
+			} else {
+				SigSpec cur = module->cell(RTLIL::escape_id(port_cell))->getPort(RTLIL::escape_id(port_port));
+				if (sigmap(sig) != sigmap(cur)) {
+					log_cmd_error("Expected connection not present: expected %s, found %s.\n", log_signal(sig), log_signal(cur));
+				}
+			}
 		}
 		else
 			log_cmd_error("Expected -set, -unset, or -port.\n");