Set MustBuildLookupTable on PrimaryContext in ExternalASTMerger

Summary:
`MustBuildLookupTable` must always be called on a primary context as we otherwise
trigger an assert, but we don't ensure that this will always happen in our code right now.

This patch explicitly requests the primary context when doing this call as this shouldn't break
anything (as calling `getPrimaryContext` on a context which is its own primary context is a no-op)
but will catch these rare cases where we somehow operate on a declaration context that is
not its own primary context.

See also D54863.

Reviewers: martong, a.sidorin, shafik

Reviewed By: martong

Subscribers: davide, rnkovacs, cfe-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D54898

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@347863 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/AST/ExternalASTMerger.cpp b/lib/AST/ExternalASTMerger.cpp
index e7ca3ac145976d312e4ea64bcd3e781b57c30e94..12e6bfc041a48b35751a0b8069f979f5ebd68571 100644 (file)
--- a/lib/AST/ExternalASTMerger.cpp
+++ b/lib/AST/ExternalASTMerger.cpp
@@ -144,14 +144,14 @@ public:
     }
     if (auto *ToTag = dyn_cast<TagDecl>(To)) {
       ToTag->setHasExternalLexicalStorage();
-      ToTag->setMustBuildLookupTable();
+      ToTag->getPrimaryContext()->setMustBuildLookupTable();
       assert(Parent.CanComplete(ToTag));
     } else if (auto *ToNamespace = dyn_cast<NamespaceDecl>(To)) {
       ToNamespace->setHasExternalVisibleStorage();
       assert(Parent.CanComplete(ToNamespace));
     } else if (auto *ToContainer = dyn_cast<ObjCContainerDecl>(To)) {
       ToContainer->setHasExternalLexicalStorage();
-      ToContainer->setMustBuildLookupTable();
+      ToContainer->getPrimaryContext()->setMustBuildLookupTable();
       assert(Parent.CanComplete(ToContainer));
     }
     return To;