Add mnemonic to parameter constants in JSON for FSM Coverage (#7531)

src/V3AstNodes.cpp

@@ -543,6 +543,22 @@ AstNetlist::AstNetlist()
     addMiscsp(m_constPoolp);
 }
 
+string AstNetlist::astConstOrigParamName(const AstConst* nodep) const {
+    if (!nodep->num().hasOrigParamName()) return "";
+    const auto it = m_constOrigParamNames.find(nodep);
+    UASSERT_OBJ(it != m_constOrigParamNames.end(), nodep, "Missing originating parameter name");
+    return it->second;
+}
+
+void AstNetlist::astConstOrigParamName(const AstConst* nodep, const string& name) {
+    UASSERT(!name.empty(), "Empty originating parameter name");
+    m_constOrigParamNames[nodep] = name;
+}
+
+void AstNetlist::astConstOrigParamNameErase(const AstConst* nodep) {
+    m_constOrigParamNames.erase(nodep);
+}
+
 void AstNetlist::timeprecisionMerge(FileLine*, const VTimescale& value) {
     const VTimescale prec = v3Global.opt.timeComputePrec(value);
     if (prec.isNone() || prec == m_timeprecision) {
@@ -1819,6 +1835,46 @@ string AstBasicDType::prettyDTypeName(bool) const {
 void AstNodeExpr::dump(std::ostream& str) const { this->AstNode::dump(str); }
 void AstNodeExpr::dumpJson(std::ostream& str) const { dumpJsonGen(str); }
 
+AstConst::~AstConst() {
+    // Only rare constants carry originating parameter-name metadata. For all other AstConst nodes,
+    // the V3Number bit keeps this destructor from touching AstNetlist's side table. When the bit is
+    // set, erase the entry before this AstConst address can be reused by a different node.
+    if (m_num.hasOrigParamName()) v3Global.rootp()->astConstOrigParamNameErase(this);
+}
+
+string AstConst::origParamName() const {
+    if (!m_num.hasOrigParamName()) return "";
+    return v3Global.rootp()->astConstOrigParamName(this);
+}
+
+void AstConst::origParamName(const string& name) {
+    UASSERT(!name.empty(), "Empty originating parameter name");
+    v3Global.rootp()->astConstOrigParamName(this, name);
+    m_num.hasOrigParamName(true);
+}
+
+void AstConst::cloneRelink() {
+    // Preserve parameter-origin metadata across AST clones; the side-table key must be this
+    // new AstConst, not the original node.
+    if (const AstConst* const oldp = clonep()) {
+        const string name = oldp->origParamName();
+        m_num.hasOrigParamName(false);
+        if (!name.empty()) origParamName(name);
+    }
+    m_num.nodep(this);
+}
+
+void AstConst::dump(std::ostream& str) const {
+    this->AstNodeExpr::dump(str);
+    const string name = origParamName();
+    if (!name.empty()) str << " origParamName=" << name;
+}
+void AstConst::dumpJson(std::ostream& str) const {
+    const string name = origParamName();
+    if (!name.empty()) dumpJsonStr(str, "origParamName", name);
+    dumpJsonGen(str);
+}
+
 bool AstNodeExpr::isLValue() const {
     if (const AstNodeVarRef* const varrefp = VN_CAST(this, NodeVarRef)) {
         return varrefp->access().isWriteOrRW();