write_json: dump default parameter values

Fixes #1823.

This will allow nextpnr to reuse the default value information already
present in yosys cells_sim.v and avoid duplicating (and probably
desyncing) this information.

1 files changed, 10 insertions, 0 deletions

diff --git a/backends/json/json.cc b/backends/json/json.cc
index 1da23bb7d..1a8b757ef 100644
--- a/backends/json/json.cc
+++ b/backends/json/json.cc
@@ -141,6 +141,12 @@ struct JsonWriter
 		write_parameters(module->attributes, /*for_module=*/true);
 		f << stringf("\n      },\n");
 
+		if (module->parameter_default_values.size()) {
+			f << stringf("      \"parameter_default_values\": {");
+			write_parameters(module->parameter_default_values, /*for_module=*/true);
+			f << stringf("\n      },\n");
+		}
+
 		f << stringf("      \"ports\": {");
 		bool first = true;
 		for (auto n : module->ports) {
@@ -310,6 +316,10 @@ struct JsonBackend : public Backend {
 		log("            <attribute_name>: <attribute_value>,\n");
 		log("            ...\n");
 		log("          },\n");
+		log("          \"parameter_default_values\": {\n");
+		log("            <parameter_name>: <parameter_value>,\n");
+		log("            ...\n");
+		log("          },\n");
 		log("          \"ports\": {\n");
 		log("            <port_name>: <port_details>,\n");
 		log("            ...\n");