r196997 - [ms-abi] Makes Virtual Base Alignment Look at All Virtual Bases

[Warren Hunt]

Author: whunt
Date: Tue Dec 10 20:21:03 2013
New Revision: 196997

URL: http://llvm.org/viewvc/llvm-project?rev=196997&view=rev
Log:
[ms-abi] Makes Virtual Base Alignment Look at All Virtual Bases

Prior to this patch, the alignment imposed by virtual bases only 
included direct virtual bases.  This patch fixes it to look at all 
virtual bases.


Modified:
    cfe/trunk/lib/AST/RecordLayoutBuilder.cpp
    cfe/trunk/test/Layout/ms-x86-pack-and-align.cpp

Modified: cfe/trunk/lib/AST/RecordLayoutBuilder.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/RecordLayoutBuilder.cpp?rev=196997&r1=196996&r2=196997&view=diff
==============================================================================
--- cfe/trunk/lib/AST/RecordLayoutBuilder.cpp (original)
+++ cfe/trunk/lib/AST/RecordLayoutBuilder.cpp Tue Dec 10 20:21:03 2013
@@ -2125,8 +2125,6 @@ public:
   /// \brief The alignment of the non-virtual portion of the record layout
   /// Only used for C++ layouts.
   CharUnits NonVirtualAlignment;
-  /// \brief The additional alignment imposed by the virtual bases.
-  CharUnits VirtualAlignment;
   /// \brief The primary base class (if one exists).
   const CXXRecordDecl *PrimaryBase;
   /// \brief The class we share our vb-pointer with.
@@ -2265,7 +2263,6 @@ MicrosoftRecordLayoutBuilder::initialize
   HasExtendableVFPtr = false;
   SharedVBPtrBase = 0;
   PrimaryBase = 0;
-  VirtualAlignment = CharUnits::One();
   LeadsWithZeroSizedBase = false;
 
   // If the record has a dynamic base class, attempt to choose a primary base
@@ -2285,7 +2282,6 @@ MicrosoftRecordLayoutBuilder::initialize
       HasZeroSizedSubObject = true;
     // Handle virtual bases.
     if (i->isVirtual()) {
-      VirtualAlignment = std::max(VirtualAlignment, getBaseAlignment(Layout));
       HasVBPtr = true;
       continue;
     }
@@ -2555,7 +2551,14 @@ void MicrosoftRecordLayoutBuilder::layou
   if (!HasVBPtr)
     return;
 
-  updateAlignment(VirtualAlignment);
+  for (CXXRecordDecl::base_class_const_iterator i = RD->vbases_begin(),
+                                                e = RD->vbases_end();
+       i != e; ++i) {
+    const CXXRecordDecl *BaseDecl =
+        cast<CXXRecordDecl>(i->getType()->getAs<RecordType>()->getDecl());
+    const ASTRecordLayout &Layout = Context.getASTRecordLayout(BaseDecl);
+    updateAlignment(getBaseAlignment(Layout));
+  }
   PreviousBaseLayout = 0;
 
   // Zero-sized v-bases obey the alignment attribute so apply it here.  The

Modified: cfe/trunk/test/Layout/ms-x86-pack-and-align.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Layout/ms-x86-pack-and-align.cpp?rev=196997&r1=196996&r2=196997&view=diff
==============================================================================
--- cfe/trunk/test/Layout/ms-x86-pack-and-align.cpp (original)
+++ cfe/trunk/test/Layout/ms-x86-pack-and-align.cpp Tue Dec 10 20:21:03 2013
@@ -114,7 +114,32 @@ struct Z : virtual B {
 
 #pragma pack(pop)
 
+struct A1 { long long a; };
+#pragma pack(push, 1)
+struct B1 : virtual A1 { char a; };
+#pragma pack(pop)
+struct C1 : B1 {};
+// CHECK: *** Dumping AST Record Layout
+// CHECK:    0 | struct C1
+// CHECK:    0 |   struct B1 (base)
+// CHECK:    0 |     (B1 vbtable pointer)
+// CHECK:    4 |     char a
+// CHECK:    8 |   struct A1 (virtual base)
+// CHECK:    8 |     long long a
+// CHECK:      | [sizeof=16, align=8
+// CHECK:      |  nvsize=5, nvalign=1]
+// CHECK-X64: *** Dumping AST Record Layout
+// CHECK-X64:    0 | struct C1
+// CHECK-X64:    0 |   struct B1 (base)
+// CHECK-X64:    0 |     (B1 vbtable pointer)
+// CHECK-X64:    8 |     char a
+// CHECK-X64:   16 |   struct A1 (virtual base)
+// CHECK-X64:   16 |     long long a
+// CHECK-X64:      | [sizeof=24, align=8
+// CHECK-X64:      |  nvsize=9, nvalign=1]
+
 int a[
 sizeof(X)+
 sizeof(Y)+
-sizeof(Z)];
+sizeof(Z)+
+sizeof(C1)];