Fix MSVC class layout for empty classes. Patch by Dmitry Sokolov.

llvm-svn: 145544

1 files changed, 9 insertions, 4 deletions

diff --git a/clang/lib/AST/RecordLayoutBuilder.cpp b/clang/lib/AST/RecordLayoutBuilder.cpp
index 60a7c2d1fe7..88a90a41729 100644
--- a/clang/lib/AST/RecordLayoutBuilder.cpp
+++ b/clang/lib/AST/RecordLayoutBuilder.cpp
@@ -1399,10 +1399,8 @@ void RecordLayoutBuilder::Layout(const CXXRecordDecl *RD) {
   }
 
   // Finally, round the size of the total struct up to the alignment
-  // of the struct itself.  Amazingly, this does not occur in the MS
-  // ABI after virtual base layout.
-  if (!isMicrosoftCXXABI() || RD->getNumVBases())
-    FinishLayout(RD);
+  // of the struct itself.
+  FinishLayout(RD);
 
 #ifndef NDEBUG
   // Check that we have base offsets for all bases.
@@ -1882,6 +1880,13 @@ void RecordLayoutBuilder::FinishLayout(const NamedDecl *D) {
     else
       setSize(CharUnits::One());
   }
+
+  // MSVC doesn't round up to the alignment of the record with virtual bases.
+  if (const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(D)) {
+    if (isMicrosoftCXXABI() && RD->getNumVBases())
+      return;
+  }
+
   // Finally, round the size of the record up to the alignment of the
   // record itself.
   uint64_t UnpaddedSize = getSizeInBits() - UnfilledBitsInLastByte;