MS ABI: Padding injected between empty vbases doesn't up required align

Only alignment is changed, not required alignment.

llvm-svn: 213217

2 files changed, 58 insertions, 1 deletions

diff --git a/clang/lib/AST/RecordLayoutBuilder.cpp b/clang/lib/AST/RecordLayoutBuilder.cpp
index b5ebbee83b5..b3deebaecfa 100644
--- a/clang/lib/AST/RecordLayoutBuilder.cpp
+++ b/clang/lib/AST/RecordLayoutBuilder.cpp
@@ -2615,7 +2615,7 @@ void MicrosoftRecordLayoutBuilder::layoutVirtualBases(const CXXRecordDecl *RD) {
     if ((PreviousBaseLayout && PreviousBaseLayout->hasZeroSizedSubObject() &&
         BaseLayout.leadsWithZeroSizedBase()) || HasVtordisp) {
       Size = Size.RoundUpToAlignment(VtorDispAlignment) + VtorDispSize;
-      RequiredAlignment = VtorDispAlignment;
+      Alignment = std::max(VtorDispAlignment, Alignment);
     }
     // Insert the virtual base.
     ElementInfo Info = getAdjustedElementInfo(BaseLayout);
diff --git a/clang/test/Layout/ms-x86-pack-and-align.cpp b/clang/test/Layout/ms-x86-pack-and-align.cpp
index 73984652aeb..5e1aae1ca75 100644
--- a/clang/test/Layout/ms-x86-pack-and-align.cpp
+++ b/clang/test/Layout/ms-x86-pack-and-align.cpp
@@ -598,6 +598,62 @@ struct ND : NC {};
 // CHECK-X64-NEXT:      | [sizeof=12, align=4
 // CHECK-X64-NEXT:      |  nvsize=8, nvalign=4]
 
+struct OA {};
+struct OB {};
+struct OC : virtual OA, virtual OB {};
+#pragma pack(push, 1)
+struct OD : OC {};
+#pragma pack(pop)
+
+// CHECK: *** Dumping AST Record Layout
+// CHECK-NEXT:    0 | struct OA (empty)
+// CHECK-NEXT:      | [sizeof=1, align=1
+// CHECK-NEXT:      |  nvsize=0, nvalign=1]
+// CHECK: *** Dumping AST Record Layout
+// CHECK-NEXT:    0 | struct OB (empty)
+// CHECK-NEXT:      | [sizeof=1, align=1
+// CHECK-NEXT:      |  nvsize=0, nvalign=1]
+// CHECK: *** Dumping AST Record Layout
+// CHECK-NEXT:    0 | struct OC
+// CHECK-NEXT:    0 |   (OC vbtable pointer)
+// CHECK-NEXT:    4 |   struct OA (virtual base) (empty)
+// CHECK-NEXT:    8 |   struct OB (virtual base) (empty)
+// CHECK-NEXT:      | [sizeof=8, align=4
+// CHECK-NEXT:      |  nvsize=4, nvalign=4]
+// CHECK: *** Dumping AST Record Layout
+// CHECK-NEXT:    0 | struct OD
+// CHECK-NEXT:    0 |   struct OC (base)
+// CHECK-NEXT:    0 |     (OC vbtable pointer)
+// CHECK-NEXT:    4 |   struct OA (virtual base) (empty)
+// CHECK-NEXT:    8 |   struct OB (virtual base) (empty)
+// CHECK-NEXT:      | [sizeof=8, align=1
+// CHECK-NEXT:      |  nvsize=4, nvalign=1]
+// CHECK-X64: *** Dumping AST Record Layout
+// CHECK-X64-NEXT:    0 | struct OA (empty)
+// CHECK-X64-NEXT:      | [sizeof=1, align=1
+// CHECK-X64-NEXT:      |  nvsize=0, nvalign=1]
+// CHECK-X64: *** Dumping AST Record Layout
+// CHECK-X64-NEXT:    0 | struct OB (empty)
+// CHECK-X64-NEXT:      | [sizeof=1, align=1
+// CHECK-X64-NEXT:      |  nvsize=0, nvalign=1]
+// CHECK-X64: *** Dumping AST Record Layout
+// CHECK-X64-NEXT:    0 | struct OC
+// CHECK-X64-NEXT:    0 |   (OC vbtable pointer)
+// CHECK-X64-NEXT:    8 |   struct OA (virtual base) (empty)
+// CHECK-X64-NEXT:   12 |   struct OB (virtual base) (empty)
+// CHECK-X64-NEXT:      | [sizeof=16, align=8
+// CHECK-X64-NEXT:      |  nvsize=8, nvalign=8]
+// CHECK-X64: *** Dumping AST Record Layout
+// CHECK-X64-NEXT:    0 | struct OD
+// CHECK-X64-NEXT:    0 |   struct OC (base)
+// CHECK-X64-NEXT:    0 |     (OC vbtable pointer)
+// CHECK-X64-NEXT:    8 |   struct OA (virtual base) (empty)
+// CHECK-X64-NEXT:   12 |   struct OB (virtual base) (empty)
+// CHECK-X64-NEXT:      | [sizeof=12, align=1
+// CHECK-X64-NEXT:      |  nvsize=8, nvalign=1]
+
+
+
 int a[
 sizeof(X)+
 sizeof(Y)+
@@ -623,4 +679,5 @@ sizeof(RB3)+
 sizeof(RC)+
 sizeof(RE)+
 sizeof(ND)+
+sizeof(OD)+
 0];