Fix PR6473.

Clang's support for weakref is now better than llvm-gcc's :-)

We don't introduce a new symbol and we correctly mark undefined references weak only if there is no
definition or regular undefined references in the same file.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@97733 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 9 insertions, 0 deletions

diff --git a/lib/CodeGen/CodeGenModule.h b/lib/CodeGen/CodeGenModule.h
index ac8332647b..c839b42559 100644
--- a/lib/CodeGen/CodeGenModule.h
+++ b/lib/CodeGen/CodeGenModule.h
@@ -29,6 +29,7 @@
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/StringMap.h"
 #include "llvm/ADT/StringSet.h"
+#include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/Support/ValueHandle.h"
 #include <list>
 
@@ -117,6 +118,11 @@ class CodeGenModule : public BlockModule {
   /// pointer lookups instead of full string lookups.
   llvm::DenseMap<const char*, llvm::GlobalValue*> GlobalDeclMap;
 
+  // WeakRefReferences - A set of references that have only been seen via
+  // a weakref so far. This is used to remove the weak of the reference if we ever
+  // see a direct reference or a definition.
+  llvm::SmallPtrSet<llvm::GlobalValue*, 10> WeakRefReferences;
+
   /// \brief Contains the strings used for mangled names.
   ///
   /// FIXME: Eventually, this should map from the semantic/canonical
@@ -243,6 +249,9 @@ public:
   void BuildThunksForVirtual(GlobalDecl GD);
   void BuildThunksForVirtualRecursive(GlobalDecl GD, GlobalDecl BaseOGD);
 
+  /// GetWeakRefReference - Get a reference to the target of VD.
+  llvm::Constant *GetWeakRefReference(const ValueDecl *VD);
+
   /// BuildThunk - Build a thunk for the given method.
   llvm::Constant *BuildThunk(GlobalDecl GD, bool Extern, 
                              const ThunkAdjustment &ThisAdjustment);