Merge block/function pointer types with objc's __weak

attribute properly and avoid bogus warning. This is
an objective-c fix only. objective-c++ follows different code
pass and requires separate fix (which will come at a later time).
Fixes radar 7214820.

llvm-svn: 95571

1 files changed, 16 insertions, 3 deletions

diff --git a/clang/lib/AST/ASTContext.cpp b/clang/lib/AST/ASTContext.cpp
index 7e03f56f62f..386a5f3c7bd 100644
--- a/clang/lib/AST/ASTContext.cpp
+++ b/clang/lib/AST/ASTContext.cpp
@@ -4303,11 +4303,24 @@ QualType ASTContext::mergeFunctionTypes(QualType lhs, QualType rhs) {
   bool allRTypes = true;
 
   // Check return type
-  QualType retType = mergeTypes(lbase->getResultType(), rbase->getResultType());
+  QualType LRES = lbase->getResultType();
+  QualType RRES = rbase->getResultType();
+  Qualifiers::GC GC_L = LRES.getObjCGCAttr();
+  Qualifiers::GC GC_R = RRES.getObjCGCAttr();
+  // __weak/__strong attribute on one function/block return type but
+  // not the other is OK.
+  if (GC_L != GC_R) {
+    if (GC_R == Qualifiers::GCNone)
+      RRES = getObjCGCQualType(RRES, GC_L);
+    else if (GC_L == Qualifiers::GCNone)
+      LRES = getObjCGCQualType(LRES, GC_R);
+  }
+  
+  QualType retType = mergeTypes(LRES, RRES);
   if (retType.isNull()) return QualType();
-  if (getCanonicalType(retType) != getCanonicalType(lbase->getResultType()))
+  if (getCanonicalType(retType) != getCanonicalType(LRES))
     allLTypes = false;
-  if (getCanonicalType(retType) != getCanonicalType(rbase->getResultType()))
+  if (getCanonicalType(retType) != getCanonicalType(RRES))
     allRTypes = false;
   // FIXME: double check this
   bool NoReturn = lbase->getNoReturnAttr() || rbase->getNoReturnAttr();