[Lldb-commits] [clang] [lldb] Reland [MS][clang] Add support for vector deleting destructors (PR #165598)

[Eli Friedman via lldb-commits]

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@@ -8281,3 +8281,53 @@ void CodeGenModule::moveLazyEmissionStates(CodeGenModule *NewBuilder) {
 
   NewBuilder->ABI->MangleCtx = std::move(ABI->MangleCtx);
 }
+
+bool CodeGenModule::classNeedsVectorDestructor(const CXXRecordDecl *RD) {
+  if (!Context.getTargetInfo().emitVectorDeletingDtors(Context.getLangOpts()))
+    return false;
+  CXXDestructorDecl *Dtor = RD->getDestructor();
+  // The compiler can't know if new[]/delete[] will be used outside of the DLL,
+  // so just force vector deleting destructor emission if dllexport is present.
+  // This matches MSVC behavior.
+  if (Dtor && Dtor->isVirtual() && Dtor->isDefined() &&
+      Dtor->hasAttr<DLLExportAttr>())
+    return true;
+
+  return RequireVectorDeletingDtor.count(RD);
+}
+
+void CodeGenModule::requireVectorDestructorDefinition(const CXXRecordDecl *RD) {
+  if (!Context.getTargetInfo().emitVectorDeletingDtors(Context.getLangOpts()))
+    return;
+  RequireVectorDeletingDtor.insert(RD);
+
+  // To reduce code size in general case we lazily emit scalar deleting
+  // destructor definition and an alias from vector deleting destructor to
+  // scalar deleting destructor. It may happen that we first emitted the scalar
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efriedma-quic wrote:

Oh, hmm.  So normally, the scalar destuctor is sufficient, but if some translation unit uses delete[], you need the vector destructor.  And you handle this by emitting a weak symbol by default, but overriding it with an actual definition if you need it.

And it looks like this is what MSVC does... so that's fine, I guess.  Feels a little convoluted, but I guess we didn't define it.

https://github.com/llvm/llvm-project/pull/165598