path: root/lib/CodeGen/CGClass.cpp

//===--- CGClass.cpp - Emit LLVM Code for C++ classes ---------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This contains code dealing with C++ code generation of classes
//
//===----------------------------------------------------------------------===//

#include "CodeGenFunction.h"
#include "clang/AST/CXXInheritance.h"
#include "clang/AST/RecordLayout.h"

using namespace clang;
using namespace CodeGen;

static uint64_t 
ComputeNonVirtualBaseClassOffset(ASTContext &Context, CXXBasePaths &Paths,
                                 unsigned Start) {
  uint64_t Offset = 0;

  const CXXBasePath &Path = Paths.front();
  for (unsigned i = Start, e = Path.size(); i != e; ++i) {
    const CXXBasePathElement& Element = Path[i];

    // Get the layout.
    const ASTRecordLayout &Layout = Context.getASTRecordLayout(Element.Class);
    
    const CXXBaseSpecifier *BS = Element.Base;
    assert(!BS->isVirtual() && "Should not see virtual bases here!");
    
    const CXXRecordDecl *Base = 
      cast<CXXRecordDecl>(BS->getType()->getAs<RecordType>()->getDecl());
    
    // Add the offset.
    Offset += Layout.getBaseClassOffset(Base) / 8;
  }

  return Offset;
}

llvm::Constant *
CodeGenModule::GetNonVirtualBaseClassOffset(const CXXRecordDecl *Class,
                                            const CXXRecordDecl *BaseClass) {
  if (Class == BaseClass)
    return 0;

  CXXBasePaths Paths(/*FindAmbiguities=*/false,
                     /*RecordPaths=*/true, /*DetectVirtual=*/false);
  if (!const_cast<CXXRecordDecl *>(Class)->
        isDerivedFrom(const_cast<CXXRecordDecl *>(BaseClass), Paths)) {
    assert(false && "Class must be derived from the passed in base class!");
    return 0;</