[clang] [clang][Itanium Mangle] Enable mangling of enclosing class for member… (PR #110503)

[Haojian Wu via cfe-commits]

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@@ -693,14 +693,13 @@ ItaniumMangleContextImpl::getEffectiveDeclContext(const Decl *D) {
     if (VD->isExternC())
       return getASTContext().getTranslationUnitDecl();
 
-  if (const auto *FD = D->getAsFunction()) {
-    if (FD->isExternC())
-      return getASTContext().getTranslationUnitDecl();
+  if (const auto *FD = getASTContext().getLangOpts().getClangABICompat() >
+                               LangOptions::ClangABI::Ver19
+                           ? D->getAsFunction()
+                           : dyn_cast<FunctionDecl>(D)) {
     // Member-like constrained friends are mangled as if they were members of
     // the enclosing class.
-    if (FD->isMemberLikeConstrainedFriend() &&
-        getASTContext().getLangOpts().getClangABICompat() >
-            LangOptions::ClangABI::Ver17)
+    if (FD->isMemberLikeConstrainedFriend())
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hokein wrote:

this looks like a behavior change, we should keep the `getClangABICompat() > LangOptions::ClangABI::Ver17` check.

https://github.com/llvm/llvm-project/pull/110503