set "keep" on modules with $assert cells in "hierarchy"

diff --git a/passes/hierarchy/hierarchy.cc b/passes/hierarchy/hierarchy.cc
index 2c77a892ae5cdeedd88423c1112a029f1d8b3732..960fc19292767f97770b74dcba0229e414125199 100644 (file)
--- a/passes/hierarchy/hierarchy.cc
+++ b/passes/hierarchy/hierarchy.cc
@@ -286,6 +286,17 @@ void hierarchy(RTLIL::Design *design, RTLIL::Module *top, bool purge_lib, bool f
        log("Removed %zd unused modules.\n", del_modules.size());
 }
 
+bool set_keep_assert(std::map<RTLIL::Module*, bool> &cache, RTLIL::Module *mod)
+{
+       if (cache.count(mod) == 0)
+               for (auto c : mod->cells()) {
+                       RTLIL::Module *m = mod->design->module(c->type);
+                       if ((m != nullptr && set_keep_assert(cache, m)) || c->type == "$assert")
+                               return cache[mod] = true;
+               }
+       return cache[mod];
+}
+
 struct HierarchyPass : public Pass {
        HierarchyPass() : Pass("hierarchy", "check, expand and clean up design hierarchy") { }
        virtual void help()
@@ -317,6 +328,11 @@ struct HierarchyPass : public Pass {
                log("        per default this pass also converts positional arguments in cells\n");
                log("        to arguments using port names. this option disables this behavior.\n");
                log("\n");
+               log("    -nokeep_asserts\n");
+               log("        per default this pass sets the \"keep\" attribute on all modules\n");
+               log("        that directly or indirectly contain one or more $assert cells. this\n");
+               log("        option disables this behavior.\n");
+               log("\n");
                log("    -top <module>\n");
                log("        use the specified top module to built a design hierarchy. modules\n");
                log("        outside this tree (unused modules) are removed.\n");
@@ -353,6 +369,7 @@ struct HierarchyPass : public Pass {
 
                bool generate_mode = false;
                bool keep_positionals = false;
+               bool nokeep_asserts = false;
                std::vector<std::string> generate_cells;
                std::vector<generate_port_decl_t> generate_ports;
 
@@ -410,6 +427,10 @@ struct HierarchyPass : public Pass {
                                keep_positionals = true;
                                continue;
                        }
+                       if (args[argidx] == "-nokeep_asserts") {
+                               nokeep_asserts = true;
+                               continue;
+                       }
                        if (args[argidx] == "-libdir" && argidx+1 < args.size()) {
                                libdirs.push_back(args[++argidx]);
                                continue;
@@ -477,6 +498,15 @@ struct HierarchyPass : public Pass {
                                        mod_it.second->attributes.erase("\\top");
                }
 
+               if (!nokeep_asserts) {
+                       std::map<RTLIL::Module*, bool> cache;
+                       for (auto mod : design->modules())
+                               if (set_keep_assert(cache, mod)) {
+                                       log("Module %s directly or indirectly contains $assert cells -> setting \"keep\" attribute.\n", log_id(mod));
+                                       mod->set_bool_attribute("\\keep");
+                               }
+               }
+
                if (!keep_positionals)
                {
                        std::set<RTLIL::Module*> pos_mods;