Add ability to layout the vtable pointer in trivial cases. I noticed

that we would silently do bad things with virtual bases in the layout
code, so, we just turn them off.  When people do better things with
them, we can turn them back on.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@77556 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 20 insertions, 6 deletions

diff --git a/lib/AST/RecordLayoutBuilder.cpp b/lib/AST/RecordLayoutBuilder.cpp
index e3581d88d2..a60a72b74f 100644
--- a/lib/AST/RecordLayoutBuilder.cpp
+++ b/lib/AST/RecordLayoutBuilder.cpp
@@ -24,11 +24,19 @@ ASTRecordLayoutBuilder::ASTRecordLayoutBuilder(ASTContext &Ctx)
   : Ctx(Ctx), Size(0), Alignment(8), StructPacking(0), NextOffset(0),
   IsUnion(false), NonVirtualSize(0), NonVirtualAlignment(8) {}
 
+void ASTRecordLayoutBuilder::LayoutVtable(const CXXRecordDecl *RD) {
+  if (RD->isPolymorphic())
+    {
+      assert (RD->getNumBases() == 0 && "no polymorphic inheritance yet");
+      int AS = 0;
+      UpdateAlignment(Ctx.Target.getPointerAlign(AS));
+      Size += Ctx.Target.getPointerWidth(AS);
+      NextOffset = Size;
+    }
+}
+
 void 
 ASTRecordLayoutBuilder::LayoutNonVirtualBases(const CXXRecordDecl *RD) {
-  assert(!RD->isPolymorphic() && 
-         "FIXME: We don't support polymorphic classes yet!");
-  
   for (CXXRecordDecl::base_class_const_iterator i = RD->bases_begin(),
        e = RD->bases_end(); i != e; ++i) {
     if (!i->isVirtual()) {
@@ -74,14 +82,20 @@ void ASTRecordLayoutBuilder::Layout(const RecordDecl *D) {
     UpdateAlignment(AA->getAlignment());
 
   // If this is a C++ class, lay out the nonvirtual bases.
-  if (Ctx.getLangOptions().CPlusPlus)
-    LayoutNonVirtualBases(cast<CXXRecordDecl>(D));
+  if (Ctx.getLangOptions().CPlusPlus) {
+    const CXXRecordDecl *RD = cast<CXXRecordDecl>(D);
+    LayoutVtable(RD);
+    LayoutNonVirtualBases(RD);
+
+    assert (RD->getNumVBases() == 0
+            && "FIXME: We don't support virtual bases yet!");
+  }
 
   LayoutFields(D);
   
   NonVirtualSize = Size;
   NonVirtualAlignment = Alignment;
-  
+
   // Finally, round the size of the total struct up to the alignment of the
   // struct itself.
   FinishLayout();