void VBTableInfo::EmitVBTableDefinition(
    CodeGenModule &CGM, const CXXRecordDecl *RD,
    llvm::GlobalVariable::LinkageTypes Linkage) const {
  assert(RD->getNumVBases() && ReusingBase->getNumVBases() &&
         "should only emit vbtables for classes with vbtables");

  const ASTRecordLayout &BaseLayout =
    CGM.getContext().getASTRecordLayout(VBPtrSubobject.getBase());
  const ASTRecordLayout &DerivedLayout =
    CGM.getContext().getASTRecordLayout(RD);

  SmallVector<llvm::Constant *, 4> Offsets;

  // The offset from ReusingBase's vbptr to itself always leads.
  CharUnits VBPtrOffset = BaseLayout.getVBPtrOffset();
  Offsets.push_back(
      llvm::ConstantInt::get(CGM.IntTy, -VBPtrOffset.getQuantity()));

  // These are laid out in the same order as in Itanium, which is the same as
  // the order of the vbase iterator.
  for (CXXRecordDecl::base_class_const_iterator I = ReusingBase->vbases_begin(),
       E = ReusingBase->vbases_end(); I != E; ++I) {
    const CXXRecordDecl *VBase = I->getType()->getAsCXXRecordDecl();
    CharUnits Offset = DerivedLayout.getVBaseClassOffset(VBase);
    assert(!Offset.isNegative());
    // Make it relative to the subobject vbptr.
    Offset -= VBPtrSubobject.getBaseOffset() + VBPtrOffset;
    Offsets.push_back(llvm::ConstantInt::get(CGM.IntTy, Offset.getQuantity()));
  }

  assert(Offsets.size() ==
         cast<llvm::ArrayType>(cast<llvm::PointerType>(GV->getType())
                               ->getElementType())->getNumElements());
  llvm::ArrayType *VBTableType =
    llvm::ArrayType::get(CGM.IntTy, Offsets.size());
  llvm::Constant *Init = llvm::ConstantArray::get(VBTableType, Offsets);
  GV->setInitializer(Init);

  // Set the correct linkage.
  GV->setLinkage(Linkage);

  // Set the right visibility.
  CGM.setTypeVisibility(GV, RD, CodeGenModule::TVK_ForVTable);
}