Optimize away __Vconfigure if empty function

src/V3EmitCHeaders.cpp

@@ -209,7 +209,9 @@ class EmitCHeader final : public EmitCConstInit {
 
         if (!VN_IS(modp, Class)) {
             decorateFirst(first, section);
-            puts("void " + protect("__Vconfigure") + "(bool first);\n");
+            if (v3Global.opt.coverage()) {
+                puts("void " + protect("__Vconfigure") + "(bool first);\n");
+            }
         } else {
             decorateFirst(first, section);
             const std::string name = V3OutFormatter::quoteNameControls(

src/V3EmitCImp.cpp

@@ -163,12 +163,12 @@ class EmitCImp final : public EmitCFunc {
                              "(" + modName + "* vlSelf, bool first);");
         }
 
-        puts("\nvoid " + modName + "::" + protect("__Vconfigure") + "(bool first) {\n");
-        puts("(void)first;  // Prevent unused variable warning\n");
         if (v3Global.opt.coverage()) {
+            puts("\nvoid " + modName + "::" + protect("__Vconfigure") + "(bool first) {\n");
+            puts("(void)first;  // Prevent unused variable warning\n");
             puts(modName + "__" + protect("_configure_coverage") + "(this, first);\n");
+            puts("}\n");
         }
-        puts("}\n");
     }
     void emitCoverageImp() {
         // Rather than putting out VL_COVER_INSERT calls directly, we do it via this

src/V3EmitCSyms.cpp

@@ -1277,15 +1277,17 @@ std::vector<std::string> EmitCSyms::getSymCtorStmts() {
         add(stmt);
     }
 
-    add("// Setup each module's pointer back to symbol table (for public functions)");
-    for (const ScopeModPair& i : m_scopes) {
-        const AstScope* const scopep = i.first;
-        AstNodeModule* const modp = i.second;
-        // first is used by AstCoverDecl's call to __vlCoverInsert
-        const bool first = !modp->user1();
-        modp->user1(true);
-        add(VIdProtect::protectIf(scopep->nameDotless(), scopep->protect()) + "."
-            + protect("__Vconfigure") + "(" + (first ? "true" : "false") + ");");
+    if (v3Global.opt.coverage()) {
+        add("// Setup each module's pointer back to symbol table (for public functions)");
+        for (const ScopeModPair& i : m_scopes) {
+            const AstScope* const scopep = i.first;
+            AstNodeModule* const modp = i.second;
+            // first is used by AstCoverDecl's call to __vlCoverInsert
+            const bool first = !modp->user1();
+            modp->user1(true);
+            add(VIdProtect::protectIf(scopep->nameDotless(), scopep->protect()) + "."
+                + protect("__Vconfigure") + "(" + (first ? "true" : "false") + ");");
+        }
     }
 
     // Every scope has the same construction shape, so all fold into one table with no

test_regress/t/t_protect_ids_key.out

@@ -12,7 +12,6 @@
   <map from="PStVCQ" to="__PVT__secret_r"/>
   <map from="PSfqS0" to="__PVT__t__DOT__secret_inst"/>
   <map from="PSScAO" to="__VactTriggered"/>
-  <map from="PSx9Nt" to="__Vconfigure"/>
   <map from="PSrjMj" to="__Vdly__secret_cyc"/>
   <map from="PS4o5S" to="__Vdpiexp_dpix_a_func_TOP__t__DOT__secret_inst"/>
   <map from="PStVA8" to="__Vdpiexp_dpix_a_task_TOP__t__DOT__secret_inst"/>