Fix a couple of problems with initialization and assignment to

__block variables where the act of initialization/assignment
itself causes the __block variable to be copied to the heap
because the variable is of block type and is being assigned
a block literal which captures the variable.

rdar://problem/9814099

llvm-svn: 136337

1 files changed, 11 insertions, 1 deletions

diff --git a/clang/lib/CodeGen/CGObjC.cpp b/clang/lib/CodeGen/CGObjC.cpp
index f81b6b75e3f..2f9ff224959 100644
--- a/clang/lib/CodeGen/CGObjC.cpp
+++ b/clang/lib/CodeGen/CGObjC.cpp
@@ -2144,10 +2144,20 @@ CodeGenFunction::EmitARCStoreStrong(const BinaryOperator *e,
   TryEmitResult result = tryEmitARCRetainScalarExpr(*this, e->getRHS());
   llvm::Value *value = result.getPointer();
 
+  bool hasImmediateRetain = result.getInt();
+
+  // If we didn't emit a retained object, and the l-value is of block
+  // type, then we need to emit the block-retain immediately in case
+  // it invalidates the l-value.
+  if (!hasImmediateRetain && e->getType()->isBlockPointerType()) {
+    value = EmitARCRetainBlock(value);
+    hasImmediateRetain = true;
+  }
+
   LValue lvalue = EmitLValue(e->getLHS());
 
   // If the RHS was emitted retained, expand this.
-  if (result.getInt()) {
+  if (hasImmediateRetain) {
     llvm::Value *oldValue =
       EmitLoadOfScalar(lvalue.getAddress(), lvalue.isVolatileQualified(),
                        lvalue.getAlignment(), e->getType(),