From 80cbf81b3b394d547a0e85a9e1e5bb592f9cb6b5 Mon Sep 17 00:00:00 2001
From: Wilson Snyder <wsnyder@wsnyder.org>
Date: Fri, 17 Mar 2023 22:27:55 -0400
Subject: [PATCH] Internals: Fix missing relink() and add assert

---
 src/V3Ast.h     | 8 +++++++-
 src/V3Clock.cpp | 6 ++++--
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/src/V3Ast.h b/src/V3Ast.h
index cee54c5b8..cae837a51 100644
--- a/src/V3Ast.h
+++ b/src/V3Ast.h
@@ -1440,6 +1440,13 @@ protected:
 
 public:
     VNRelinker() = default;
+    ~VNRelinker() {
+        // Relink is needed so m_iterpp's get restored, e.g. can't have:
+        // ->unlinkFrBack(relinker);
+        // if (only_sometimes) relinker.relink(newp);
+        UDEBUGONLY(
+            UASSERT_STATIC(!m_backp, "Active linker must be relink()ed before destruction"););
+    }
     inline void relink(AstNode* newp);
     AstNode* oldp() const { return m_oldp; }
     void dump(std::ostream& str = std::cout) const;
@@ -1645,7 +1652,6 @@ public:
     bool brokeExistsAbove() const { return brokeExists() && (m_brokenState >> 7); }
     bool brokeExistsBelow() const { return brokeExists() && !(m_brokenState >> 7); }
     // Note: brokeExistsBelow is not quite precise, as it is true for sibling nodes as well
-    bool brokeIterpp() const { return !!m_iterpp; }
 
     // CONSTRUCTORS
     virtual ~AstNode() = default;
diff --git a/src/V3Clock.cpp b/src/V3Clock.cpp
index f2a537555..1a7be8041 100644
--- a/src/V3Clock.cpp
+++ b/src/V3Clock.cpp
@@ -146,17 +146,19 @@ private:
         UASSERT_OBJ(nodep->hasClocked(), nodep, "Should have been converted by V3Sched");
         UASSERT_OBJ(nodep->stmtsp(), nodep, "Should not have been created if empty");
 
-        VNRelinker relinker;
-        nodep->unlinkFrBack(&relinker);
         AstNode* const stmtsp = nodep->stmtsp()->unlinkFrBackWithNext();
 
         // Create 'if' statement, if needed
         if (!m_lastSenp || !nodep->sensesp()->sameTree(m_lastSenp)) {
+            VNRelinker relinker;
+            nodep->unlinkFrBack(&relinker);
             clearLastSen();
             m_lastSenp = nodep->sensesp();
             // Make a new if statement
             m_lastIfp = makeActiveIf(m_lastSenp);
             relinker.relink(m_lastIfp);
+        } else {
+            nodep->unlinkFrBack();
         }
 
         // Move statements to if