Re-land [mangle] Fix mangling where an extra mangle context is required.

This reverts r374268 (git commit c34385d07c7d59447bf836b740f032235391d121)

I think I reverted this by mistake, so I'm relanding it. While my bisect
found this revision, I think the crashes I'm seeing locally must be
environmental. Maybe the version of clang I'm using miscompiles tot
clang.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@374269 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 10 insertions, 0 deletions

diff --git a/lib/AST/ASTContext.cpp b/lib/AST/ASTContext.cpp
index a41b64ffcc..8dd57f2bd2 100644
--- a/lib/AST/ASTContext.cpp
+++ b/lib/AST/ASTContext.cpp
@@ -10261,6 +10261,16 @@ ASTContext::getManglingNumberContext(const DeclContext *DC) {
   return *MCtx;
 }
 
+MangleNumberingContext &
+ASTContext::getManglingNumberContext(NeedExtraManglingDecl_t, const Decl *D) {
+  assert(LangOpts.CPlusPlus); // We don't need mangling numbers for plain C.
+  std::unique_ptr<MangleNumberingContext> &MCtx =
+      ExtraMangleNumberingContexts[D];
+  if (!MCtx)
+    MCtx = createMangleNumberingContext();
+  return *MCtx;
+}
+
 std::unique_ptr<MangleNumberingContext>
 ASTContext::createMangleNumberingContext() const {
   return ABI->createMangleNumberingContext();