[MS] Don't bail on replacing dllimport vbase dtors with base dtors

Fix PR32990 by effectively reverting r283063 and solving it a different
way.

We want to limit the hack to not replace equivalent available_externally
dtors specifically to libc++, which uses always_inline. It seems certain
versions of libc++ do not provide all the symbols that an explicit
template instantiation is expected to provide.

If we get to the code that forms a real alias, only *then* check if this
is available_externally, and do that by asking a better question, which
is "is this a declaration for the linker?", because *that's* what means
we can't form an alias to it.

As a follow-on simplification, remove the InEveryTU parameter. Its last
use guarded this code for forming aliases, but we should never form
aliases to declarations, regardless of what we know about every TU.

llvm-svn: 315656

1 files changed, 1 insertions, 2 deletions

diff --git a/clang/lib/CodeGen/CodeGenModule.h b/clang/lib/CodeGen/CodeGenModule.h
index c1a31c9..c28c62e 100644
--- a/clang/lib/CodeGen/CodeGenModule.h
+++ b/clang/lib/CodeGen/CodeGenModule.h
@@ -1145,8 +1145,7 @@ public:
   /// are emitted lazily.
   void EmitGlobal(GlobalDecl D);
 
-  bool TryEmitDefinitionAsAlias(GlobalDecl Alias, GlobalDecl Target,
-                                bool InEveryTU);
+  bool TryEmitDefinitionAsAlias(GlobalDecl Alias, GlobalDecl Target);
   bool TryEmitBaseDestructorAsAlias(const CXXDestructorDecl *D);
 
   /// Set attributes for a global definition.