Do not do the block-specific rewrite when there is no block literals.

Fixes radar 7546096.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@93519 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Frontend/RewriteObjC.cpp

@@ -4043,7 +4043,7 @@ std::string RewriteObjC::SynthesizeBlockDescriptor(std::string DescTag,
 void RewriteObjC::SynthesizeBlockLiterals(SourceLocation FunLocStart,
                                           const char *FunName) {
   // Insert declaration for the function in which block literal is used.
-  if (CurFunctionDeclToDeclareForBlock)
+  if (CurFunctionDeclToDeclareForBlock && !Blocks.empty())
     RewriteBlockLiteralFunctionDecl(CurFunctionDeclToDeclareForBlock);
   // Insert closures that were part of the function.
   for (unsigned i = 0; i < Blocks.size(); i++) {

test/Rewriter/rewrite-extern-c.mm

@@ -0,0 +1,8 @@
+// RUN: %clang_cc1 -x objective-c++ -fblocks -rewrite-objc -o - %s
+// radar 7546096
+
+extern "C" {
+        short foo() { } 
+}
+typedef unsigned char Boolean;
+