Fix alignment of class derived from empty class.

The record layout code didn't properly take into account that
an empty class at offset 0 can have an alignment greater than 1.

Patch by Andrea Di Biagio.

llvm-svn: 186370

1 files changed, 4 insertions, 3 deletions

diff --git a/clang/lib/AST/RecordLayoutBuilder.cpp b/clang/lib/AST/RecordLayoutBuilder.cpp
index 51b1c062e0d..5df372639da 100644
--- a/clang/lib/AST/RecordLayoutBuilder.cpp
+++ b/clang/lib/AST/RecordLayoutBuilder.cpp
@@ -1532,18 +1532,19 @@ CharUnits RecordLayoutBuilder::LayoutBase(const BaseSubobjectInfo *Base) {
     }
   }
   
+  CharUnits UnpackedBaseAlign = Layout.getNonVirtualAlign();
+  CharUnits BaseAlign = (Packed) ? CharUnits::One() : UnpackedBaseAlign;
+ 
   // If we have an empty base class, try to place it at offset 0.
   if (Base->Class->isEmpty() &&
       (!HasExternalLayout || Offset == CharUnits::Zero()) &&
       EmptySubobjects->CanPlaceBaseAtOffset(Base, CharUnits::Zero())) {
     setSize(std::max(getSize(), Layout.getSize()));
+    UpdateAlignment(BaseAlign, UnpackedBaseAlign);
 
     return CharUnits::Zero();
   }
 
-  CharUnits UnpackedBaseAlign = Layout.getNonVirtualAlign();
-  CharUnits BaseAlign = (Packed) ? CharUnits::One() : UnpackedBaseAlign;
-
   // The maximum field alignment overrides base align.
   if (!MaxFieldAlignment.isZero()) {
     BaseAlign = std::min(BaseAlign, MaxFieldAlignment);