Prevent use after free caused by accessing a member into a dense set.

The member gets invalidated as elements are added to the dense set. Directly
access the underlying pointer instead. Not sure how to create a test case for
this :-(. Maybe Richard can help.

llvm-svn: 229673

1 files changed, 2 insertions, 1 deletions

diff --git a/clang/lib/Serialization/ASTReader.cpp b/clang/lib/Serialization/ASTReader.cpp
index a0cb7b506bd..3125b8e43e9 100644
--- a/clang/lib/Serialization/ASTReader.cpp
+++ b/clang/lib/Serialization/ASTReader.cpp
@@ -6628,7 +6628,8 @@ ASTReader::FindExternalVisibleDeclsByName(const DeclContext *DC,
       auto Merged = MergedLookups.find(DC);
       if (Merged != MergedLookups.end()) {
         for (unsigned I = 0; I != Merged->second.size(); ++I) {
-          LookUpInContexts(Merged->second[I]);
+          const DeclContext *Context = Merged->second[I];
+          LookUpInContexts(Context);
           // We might have just added some more merged lookups. If so, our
           // iterator is now invalid, so grab a fresh one before continuing.
           Merged = MergedLookups.find(DC);