1 files changed, 13 insertions, 5 deletions
diff --git a/lib/CodeGen/CGBlocks.cpp b/lib/CodeGen/CGBlocks.cpp
index 1d8b326d20..d181da2de6 100644
--- a/lib/CodeGen/CGBlocks.cpp
+++ b/lib/CodeGen/CGBlocks.cpp
@@ -428,7 +428,11 @@ static void computeBlockInfo(CodeGenModule &CGM, CodeGenFunction *CGF,
   // to get reproducible results.  There should probably be an
   // llvm::array_pod_stable_sort.
   std::stable_sort(layout.begin(), layout.end());
-
+  
+  // Needed for blocks layout info.
+  info.BlockHeaderForcedGapOffset = info.BlockSize;
+  info.BlockHeaderForcedGapSize = CharUnits::Zero();
+  
   CharUnits &blockSize = info.BlockSize;
   info.BlockAlign = std::max(maxFieldAlign, info.BlockAlign);
 
@@ -469,17 +473,22 @@ static void computeBlockInfo(CodeGenModule &CGM, CodeGenFunction *CGF,
         endAlign = getLowBit(blockSize);
 
         // ...until we get to the alignment of the maximum field.
-        if (endAlign >= maxFieldAlign)
+        if (endAlign >= maxFieldAlign) {
+          if (li == first) {
+            // No user field was appended. So, a gap was added.
+            // Save total gap size for use in block layout bit map.
+            info.BlockHeaderForcedGapSize = li->Size;
+          }
           break;
+        }
       }
-
       // Don't re-append everything we just appended.
       layout.erase(first, li);
     }
   }
 
   assert(endAlign == getLowBit(blockSize));
-
+  
   // At this point, we just have to add padding if the end align still
   // isn't aligned right.
   if (endAlign < maxFieldAlign) {
@@ -494,7 +503,6 @@ static void computeBlockInfo(CodeGenModule &CGM, CodeGenFunction *CGF,
 
   assert(endAlign >= maxFieldAlign);
   assert(endAlign == getLowBit(blockSize));
-
   // Slam everything else on now.  This works because they have
   // strictly decreasing alignment and we expect that size is always a
   // multiple of alignment.