path: root/lib/Analysis/DebugInfo.cpp

//===--- DebugInfo.cpp - Debug Information Helper Classes -----------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the helper classes used to build and interpret debug
// information in LLVM IR form.
//
//===----------------------------------------------------------------------===//

#include "llvm/Analysis/DebugInfo.h"
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Intrinsics.h"
#include "llvm/IntrinsicInst.h"
#include "llvm/Instructions.h"
#include "llvm/LLVMContext.h"
#include "llvm/Module.h"
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/Support/Dwarf.h"
#include "llvm/Support/DebugLoc.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
using namespace llvm::dwarf;

//===----------------------------------------------------------------------===//
// DIDescriptor
//===----------------------------------------------------------------------===//

/// ValidDebugInfo - Return true if V represents valid debug info value.
/// FIXME : Add DIDescriptor.isValid()
bool DIDescriptor::ValidDebugInfo(MDNode *N, CodeGenOpt::Level OptLevel) {
  if (!N)
    return false;

  DIDescriptor DI(N);

  // Check current version. Allow Version6 for now.
  unsigned Version = DI.getVersion();
  if (Version != LLVMDebugVersion && Version != LLVMDebugVersion6)
    return false;

  unsigned Tag = DI.getTag();
  switch (Tag) {
  case DW_TAG_variable:
    assert(DIVariable(N).Verify() && "Invalid DebugInfo value");
    break;
  case DW_TAG_compile_unit:
    assert(DICompileUnit(N).Verify() && "Invalid DebugInfo value");
    break;
  case DW_TAG_subprogram:
    assert(DISubprogram(N).Verify() && "Invalid DebugInfo value");
    break;
  case DW_TAG_lexical_block:
    // FIXME: This interfers with the quality of generated code during
    // optimization.
    if (OptLevel != CodeGenOpt::None)
      return false;
    // FALLTHROUGH
  default:
    break;
  }

  return true;
}

DIDescriptor::DIDescriptor(MDNode *N, unsigned RequiredTag) {
  DbgNode = N;

  // If this is non-null, check to see if the Tag matches. If not, set to null.
  if (N && getTag() != RequiredTag) {
    DbgNode = 0;
  }
}

const std::string &
DIDescriptor::getStringField(unsigned Elt, std::string &Result) const {
  Result.clear();
  if (DbgNode == 0)
    return Result;

  if (Elt < DbgNode->getNumElements())
    if (MDString *MDS = dyn_cast_or_null<MDString>(DbgNode->getElement(Elt))) {
      Result.assign(MDS->begin(),