YouCompleteMe/cpp/llvm/lib/DebugInfo/DWARFContext.cpp

//===-- DWARFContext.cpp --------------------------------------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#include "DWARFContext.h"
#include "llvm/Support/Dwarf.h"
#include "llvm/Support/Format.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm>
using namespace llvm;
using namespace dwarf;

void DWARFContext::dump(raw_ostream &OS) {
  OS << ".debug_abbrev contents:\n";
  getDebugAbbrev()->dump(OS);

  OS << "\n.debug_info contents:\n";
  for (unsigned i = 0, e = getNumCompileUnits(); i != e; ++i)
    getCompileUnitAtIndex(i)->dump(OS);

  OS << "\n.debug_aranges contents:\n";
  DataExtractor arangesData(getARangeSection(), isLittleEndian(), 0);
  uint32_t offset = 0;
  DWARFDebugArangeSet set;
  while (set.extract(arangesData, &offset))
    set.dump(OS);

  OS << "\n.debug_lines contents:\n";
  for (unsigned i = 0, e = getNumCompileUnits(); i != e; ++i) {
    DWARFCompileUnit *cu = getCompileUnitAtIndex(i);
    unsigned stmtOffset =
      cu->getCompileUnitDIE()->getAttributeValueAsUnsigned(cu, DW_AT_stmt_list,
                                                           -1U);
    if (stmtOffset != -1U) {
      DataExtractor lineData(getLineSection(), isLittleEndian(),
                             cu->getAddressByteSize());
      DWARFDebugLine::DumpingState state(OS);
      DWARFDebugLine::parseStatementTable(lineData, &stmtOffset, state);
    }
  }

  OS << "\n.debug_str contents:\n";
  DataExtractor strData(getStringSection(), isLittleEndian(), 0);
  offset = 0;
  uint32_t lastOffset = 0;
  while (const char *s = strData.getCStr(&offset)) {
    OS << format("0x%8.8x: \"%s\"\n", lastOffset, s);
    lastOffset = offset;
  }
}

const DWARFDebugAbbrev *DWARFContext::getDebugAbbrev() {
  if (Abbrev)
    return Abbrev.get();

  DataExtractor abbrData(getAbbrevSection(), isLittleEndian(), 0);

  Abbrev.reset(new DWARFDebugAbbrev());
  Abbrev->parse(abbrData);
  return Abbrev.get();
}

const DWARFDebugAranges *DWARFContext::getDebugAranges() {
  if (Aranges)
    return Aranges.get();

  DataExtractor arangesData(getARangeSection(), isLittleEndian(), 0);

  Aranges.reset(new DWARFDebugAranges());
  Aranges->extract(arangesData);
  if (Aranges->isEmpty()) // No aranges in file, generate them from the DIEs.
    Aranges->generate(this);
  return Aranges.get();
}

const DWARFDebugLine::LineTable *
DWARFContext::getLineTableForCompileUnit(DWARFCompileUnit *cu) {
  if (!Line)
    Line.reset(new DWARFDebugLine());

  unsigned stmtOffset =
    cu->getCompileUnitDIE()->getAttributeValueAsUnsigned(cu, DW_AT_stmt_list,
                                                         -1U);
  if (stmtOffset == -1U)
    return 0; // No line table for this compile unit.

  // See if the line table is cached.
  if (const DWARFDebugLine::LineTable *lt = Line->getLineTable(stmtOffset))
    return lt;

  // We have to parse it first.
  DataExtractor lineData(getLineSection(), isLittleEndian(),
                         cu->getAddressByteSize());
  return Line->getOrParseLineTable(lineData, stmtOffset);
}

void DWARFContext::parseCompileUnits() {
  uint32_t offset = 0;
  const DataExtractor &debug_info_data = DataExtractor(getInfoSection(),
                                                       isLittleEndian(), 0);
  while (debug_info_data.isValidOffset(offset)) {
    CUs.push_back(DWARFCompileUnit(*this));
    if (!CUs.back().extract(debug_info_data, &offset)) {
      CUs.pop_back();
      break;
    }

    offset = CUs.back().getNextCompileUnitOffset();
  }
}

namespace {
  struct OffsetComparator {
    bool operator()(const DWARFCompileUnit &LHS,
                    const DWARFCompileUnit &RHS) const {
      return LHS.getOffset() < RHS.getOffset();
    }
    bool operator()(const DWARFCompileUnit &LHS, uint32_t RHS) const {
      return LHS.getOffset() < RHS;
    }
    bool operator()(uint32_t LHS, const DWARFCompileUnit &RHS) const {
      return LHS < RHS.getOffset();
    }
  };
}

DWARFCompileUnit *DWARFContext::getCompileUnitForOffset(uint32_t offset) {
  if (CUs.empty())
    parseCompileUnits();

  DWARFCompileUnit *i = std::lower_bound(CUs.begin(), CUs.end(), offset,
                                         OffsetComparator());
  if (i != CUs.end())
    return &*i;
  return 0;
}

DILineInfo DWARFContext::getLineInfoForAddress(uint64_t address) {
  // First, get the offset of the compile unit.
  uint32_t cuOffset = getDebugAranges()->findAddress(address);
  // Retrieve the compile unit.
  DWARFCompileUnit *cu = getCompileUnitForOffset(cuOffset);
  if (!cu)
    return DILineInfo("<invalid>", 0, 0);
  // Get the line table for this compile unit.
  const DWARFDebugLine::LineTable *lineTable = getLineTableForCompileUnit(cu);
  if (!lineTable)
    return DILineInfo("<invalid>", 0, 0);
  // Get the index of the row we're looking for in the line table.
  uint64_t hiPC =
    cu->getCompileUnitDIE()->getAttributeValueAsUnsigned(cu, DW_AT_high_pc,
                                                         -1ULL);
  uint32_t rowIndex = lineTable->lookupAddress(address, hiPC);
  if (rowIndex == -1U)
    return DILineInfo("<invalid>", 0, 0);

  // From here, contruct the DILineInfo.
  const DWARFDebugLine::Row &row = lineTable->Rows[rowIndex];
  const std::string &fileName = lineTable->Prologue.FileNames[row.File-1].Name;

  return DILineInfo(fileName.c_str(), row.Line, row.Column);
}

void DWARFContextInMemory::anchor() { }