[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.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@196997 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/AST/RecordLayoutBuilder.cpp b/lib/AST/RecordLayoutBuilder.cpp
index a5b07384dc8d45c8b9f279a87e63dcb5963dc4c8..112e6d6981d5375d857a87fa00c389328eab31be 100644 (file)
--- a/lib/AST/RecordLayoutBuilder.cpp
+++ b/lib/AST/RecordLayoutBuilder.cpp
@@ -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::initializeCXXLayout(const CXXRecordDecl *RD) {
   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::initializeCXXLayout(const CXXRecordDecl *RD) {
       HasZeroSizedSubObject = true;
     // Handle virtual bases.
     if (i->isVirtual()) {
-      VirtualAlignment = std::max(VirtualAlignment, getBaseAlignment(Layout));
       HasVBPtr = true;
       continue;
     }
@@ -2555,7 +2551,14 @@ void MicrosoftRecordLayoutBuilder::layoutVirtualBases(const CXXRecordDecl *RD) {
   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

diff --git a/test/Layout/ms-x86-pack-and-align.cpp b/test/Layout/ms-x86-pack-and-align.cpp
index f9f2b30f5f73e006aa18b040392f51a0442ee572..c7bf4d31579bc46add84e160fb7938987a43703b 100644 (file)
--- a/test/Layout/ms-x86-pack-and-align.cpp
+++ b/test/Layout/ms-x86-pack-and-align.cpp
@@ -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)];