Objective-C. Fixes an assert where because of captured

variable in block is over-aligned with an align
attribute causing block metadata size not be multiple
of alignment. rdar://17878679


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@215449 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/CGBlocks.cpp

@@ -539,6 +539,16 @@ static void computeBlockInfo(CodeGenModule &CGM, CodeGenFunction *CGF,
   // multiple of alignment.
   for (SmallVectorImpl<BlockLayoutChunk>::iterator
          li = layout.begin(), le = layout.end(); li != le; ++li) {
+    if (endAlign < li->Alignment) {
+      // size may not be multiple of alignment. This can only happen with
+      // an over-aligned variable. We will be adding a padding field to
+      // make the size be multiple of alignment.
+      CharUnits padding = li->Alignment - endAlign;
+      elementTypes.push_back(llvm::ArrayType::get(CGM.Int8Ty,
+                                                  padding.getQuantity()));
+      blockSize += padding;
+      endAlign = getLowBit(blockSize);
+    }
     assert(endAlign >= li->Alignment);
     li->setIndex(info, elementTypes.size());
     elementTypes.push_back(li->Type);

test/CodeGenObjC/block-over-align.m

@@ -0,0 +1,25 @@
+// RUN: %clang_cc1 -fblocks -triple x86_64-apple-darwin -emit-llvm -o /dev/null %s
+// rdar://17878679
+
+typedef struct
+{
+  int i;
+} GAXBackboardState  __attribute__ ((aligned(32))); // minimum alignment is 32-byte boundary
+
+@interface GAXSpringboard @end
+
+@implementation GAXSpringboard
+{
+ GAXBackboardState _reflectedBackboardState;
+}
+
+- (void) MyMethod
+{
+ GAXBackboardState newBackboardState;
+ ^{
+    _reflectedBackboardState = newBackboardState;
+    return newBackboardState.i;
+  }();
+}
+@end
+