From 3d073c9534d9f84acf8ae6b9e3e692bb21ae47da Mon Sep 17 00:00:00 2001
From: Wilson Snyder <wsnyder@wsnyder.org>
Date: Sun, 23 Aug 2020 20:00:39 -0400
Subject: [PATCH] Fix class extends to use virtual destruction

---
 src/V3AstNodes.cpp | 6 +++++-
 src/V3AstNodes.h   | 3 +++
 src/V3CCtors.cpp   | 4 +++-
 src/V3LinkDot.cpp  | 2 ++
 4 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/src/V3AstNodes.cpp b/src/V3AstNodes.cpp
index b3b9c2d32..8f140aa9e 100644
--- a/src/V3AstNodes.cpp
+++ b/src/V3AstNodes.cpp
@@ -1095,7 +1095,11 @@ void AstClass::repairCache() {
     clearCache();
     for (AstNode* itemp = membersp(); itemp; itemp = itemp->nextp()) { insertCache(itemp); }
 }
-void AstClass::dump(std::ostream& str) const { this->AstNode::dump(str); }
+void AstClass::dump(std::ostream& str) const {
+    this->AstNode::dump(str);
+    if (isExtended()) str << " [EXT]";
+    if (isVirtual()) str << " [VIRT]";
+}
 AstClass* AstClassExtends::classp() const {
     AstClassRefDType* refp = VN_CAST(dtypep(), ClassRefDType);
     UASSERT_OBJ(refp, this, "class extends non-ref");
diff --git a/src/V3AstNodes.h b/src/V3AstNodes.h
index 2ce8f2ffb..f4dd547ff 100644
--- a/src/V3AstNodes.h
+++ b/src/V3AstNodes.h
@@ -305,6 +305,7 @@ class AstClass : public AstNodeModule {
     MemberNameMap m_members;  // Members or method children
     AstClassPackage* m_packagep = nullptr;  // Class package this is under
     bool m_virtual = false;  // Virtual class
+    bool m_extended = false;  // Is extension or extended by other classes
     void insertCache(AstNode* nodep);
 
 public:
@@ -336,6 +337,8 @@ public:
         const auto it = m_members.find(name);
         return (it == m_members.end()) ? nullptr : it->second;
     }
+    bool isExtended() const { return m_extended; }
+    void isExtended(bool flag) { m_extended = flag; }
     bool isVirtual() const { return m_virtual; }
     void isVirtual(bool flag) { m_virtual = flag; }
 };
diff --git a/src/V3CCtors.cpp b/src/V3CCtors.cpp
index 14d99fc86..55c60685e 100644
--- a/src/V3CCtors.cpp
+++ b/src/V3CCtors.cpp
@@ -170,10 +170,12 @@ void V3CCtors::cctorsAll() {
                 }
             }
         }
-        if (VN_IS(modp, Class)) {
+        if (AstClass* classp = VN_CAST(modp, Class)) {
             AstCFunc* funcp = new AstCFunc(modp->fileline(), "~", nullptr, "");
             funcp->isDestructor(true);
             funcp->isStatic(false);
+            // If can be referred to by base pointer, need virtual delete
+            funcp->isVirtual(classp->isExtended());
             funcp->slow(false);
             modp->addStmtp(funcp);
         }
diff --git a/src/V3LinkDot.cpp b/src/V3LinkDot.cpp
index 985eb8e26..f6916a082 100644
--- a/src/V3LinkDot.cpp
+++ b/src/V3LinkDot.cpp
@@ -2709,6 +2709,8 @@ private:
                             AstClassRefDType* newp
                                 = new AstClassRefDType{nodep->fileline(), classp};
                             cextp->childDTypep(newp);
+                            classp->isExtended(true);
+                            nodep->isExtended(true);
                             VL_DO_DANGLING(cpackagerefp->unlinkFrBack()->deleteTree(),
                                            cpackagerefp);
                             ok = true;