1 files changed, 726 insertions, 0 deletions
diff --git a/externals/breakpad/src/common/mac/dump_syms.cc b/externals/breakpad/src/common/mac/dump_syms.cc
new file mode 100644
index 0000000000..c06945e483
--- /dev/null
+++ b/externals/breakpad/src/common/mac/dump_syms.cc
@@ -0,0 +1,726 @@
+// -*- mode: c++ -*-
+
+// Copyright 2011 Google LLC
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google LLC nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Author: Jim Blandy <jimb@mozilla.com> <jimb@red-bean.com>
+
+// dump_syms.cc: Create a symbol file for use with minidumps
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>  // Must come first
+#endif
+
+#include "common/mac/dump_syms.h"
+
+#include <assert.h>
+#include <dirent.h>
+#include <errno.h>
+#include <mach-o/arch.h>
+#include <mach-o/fat.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <ostream>
+#include <string>
+#include <vector>
+
+#include "common/dwarf/bytereader-inl.h"
+#include "common/dwarf/dwarf2reader.h"
+#include "common/dwarf_cfi_to_module.h"
+#include "common/dwarf_cu_to_module.h"
+#include "common/dwarf_line_to_module.h"
+#include "common/dwarf_range_list_handler.h"
+#include "common/mac/file_id.h"
+#include "common/mac/arch_utilities.h"
+#include "common/mac/macho_reader.h"
+#include "common/module.h"
+#include "common/path_helper.h"
+#include "common/scoped_ptr.h"
+#include "common/stabs_reader.h"
+#include "common/stabs_to_module.h"
+#include "common/symbol_data.h"
+
+#ifndef CPU_TYPE_ARM
+#define CPU_TYPE_ARM (static_cast<cpu_type_t>(12))
+#endif //  CPU_TYPE_ARM
+
+#ifndef CPU_TYPE_ARM64
+#define CPU_TYPE_ARM64 (static_cast<cpu_type_t>(16777228))
+#endif  // CPU_TYPE_ARM64
+
+using google_breakpad::ByteReader;
+using google_breakpad::DwarfCUToModule;
+using google_breakpad::DwarfLineToModule;
+using google_breakpad::DwarfRangeListHandler;
+using google_breakpad::mach_o::FatReader;
+using google_breakpad::mach_o::FileID;
+using google_breakpad::mach_o::Section;
+using google_breakpad::mach_o::Segment;
+using google_breakpad::Module;
+using google_breakpad::StabsReader;
+using google_breakpad::StabsToModule;
+using google_breakpad::scoped_ptr;
+using std::make_pair;
+using std::pair;
+using std::string;
+using std::vector;
+
+namespace {
+// Return a vector<string> with absolute paths to all the entries
+// in directory (excluding . and ..).
+vector<string> list_directory(const string& directory) {
+  vector<string> entries;
+  DIR* dir = opendir(directory.c_str());
+  if (!dir) {
+    return entries;
+  }
+
+  string path = directory;
+  if (path[path.length() - 1] != '/') {
+    path += '/';
+  }
+
+  struct dirent* entry = NULL;
+  while ((entry = readdir(dir))) {
+    if (strcmp(entry->d_name, ".") != 0 && strcmp(entry->d_name, "..") != 0) {
+      entries.push_back(path + entry->d_name);
+    }
+  }
+
+  closedir(dir);
+  return entries;
+}
+}
+
+namespace google_breakpad {
+
+bool DumpSymbols::Read(const string& filename) {
+  selected_object_file_ = nullptr;
+  struct stat st;
+  if (stat(filename.c_str(), &st) == -1) {
+    fprintf(stderr, "Could not access object file %s: %s\n",
+            filename.c_str(), strerror(errno));
+    return false;
+  }
+
+  from_disk_ = true;
+
+  // Does this filename refer to a dSYM bundle?
+  string contents_path = filename + "/Contents/Resources/DWARF";
+  string object_filename;
+  if (S_ISDIR(st.st_mode) &&
+      access(contents_path.c_str(), F_OK) == 0) {
+    // If there's one file under Contents/Resources/DWARF then use that,
+    // otherwise bail out.
+    const vector<string> entries = list_directory(contents_path);
+    if (entries.size() == 0) {
+      fprintf(stderr, "Unable to find DWARF-bearing file in bundle: %s\n",
+              filename.c_str());
+      return false;
+    }
+    if (entries.size() > 1) {
+      fprintf(stderr, "Too many DWARF files in bundle: %s\n",
+              filename.c_str());
+      return false;
+    }
+
+    object_filename = entries[0];
+  } else {
+    object_filename = filename;
+  }
+
+  // Read the file's contents into memory.
+  bool read_ok = true;
+  string error;
+  scoped_array<uint8_t> contents;
+  off_t total = 0;
+  if (stat(object_filename.c_str(), &st) != -1) {
+    FILE* f = fopen(object_filename.c_str(), "rb");
+    if (f) {
+      contents.reset(new uint8_t[st.st_size]);
+      while (total < st.st_size && !feof(f)) {
+        size_t read = fread(&contents[0] + total, 1, st.st_size - total, f);
+        if (read == 0) {
+          if (ferror(f)) {
+            read_ok = false;
+            error = strerror(errno);
+          }
+          break;
+        }
+        total += read;
+      }
+      fclose(f);
+    } else {
+      error = strerror(errno);
+    }
+  }
+
+  if (!read_ok) {
+    fprintf(stderr, "Error reading object file: %s: %s\n",
+            object_filename.c_str(), error.c_str());
+    return false;
+  }
+  return ReadData(contents.release(), total, object_filename);
+}
+
+bool DumpSymbols::ReadData(uint8_t* contents, size_t size,
+                           const std::string& filename) {
+  contents_.reset(contents);
+  size_ = size;
+  object_filename_ = filename;
+
+  // Get the list of object files present in the file.
+  FatReader::Reporter fat_reporter(object_filename_);
+  FatReader fat_reader(&fat_reporter);
+  if (!fat_reader.Read(contents_.get(), size)) {
+    return false;
+  }
+
+  // Get our own copy of fat_reader's object file list.
+  size_t object_files_count;
+  const SuperFatArch* object_files =
+    fat_reader.object_files(&object_files_count);
+  if (object_files_count == 0) {
+    fprintf(stderr, "Fat binary file contains *no* architectures: %s\n",
+            object_filename_.c_str());
+    return false;
+  }
+  object_files_.resize(object_files_count);
+  memcpy(&object_files_[0], object_files,
+         sizeof(SuperFatArch) * object_files_count);
+
+  return true;
+}
+
+bool DumpSymbols::SetArchitecture(const ArchInfo& info) {
+  // Find the best match for the architecture the user requested.
+  const SuperFatArch* best_match =
+      FindBestMatchForArchitecture(info.cputype, info.cpusubtype);
+  if (!best_match) return false;
+
+  // Record the selected object file.
+  selected_object_file_ = best_match;
+  return true;
+}
+
+
+SuperFatArch* DumpSymbols::FindBestMatchForArchitecture(
+    cpu_type_t cpu_type,
+    cpu_subtype_t cpu_subtype) {
+  SuperFatArch* closest_match = nullptr;
+  for (auto& object_file : object_files_) {
+    if (static_cast<cpu_type_t>(object_file.cputype) == cpu_type) {
+      // If there's an exact match, return it directly.
+      if ((static_cast<cpu_subtype_t>(object_file.cpusubtype) &
+           ~CPU_SUBTYPE_MASK) == (cpu_subtype & ~CPU_SUBTYPE_MASK)) {
+        return &object_file;
+      }
+      // Otherwise, hold on to this as the closest match since at least the CPU
+      // type matches.
+      if (!closest_match) {
+        closest_match = &object_file;
+      }
+    }
+  }
+  // No exact match found.
+  fprintf(stderr,
+          "Failed to find an exact match for an object file with cpu "
+          "type: %d and cpu subtype: %d.\n",
+          cpu_type, cpu_subtype);
+  if (closest_match) {
+    fprintf(stderr, "Using %s as the closest match.\n",
+            GetNameFromCPUType(closest_match->cputype,
+                               closest_match->cpusubtype));
+    return closest_match;
+  }
+  return nullptr;
+}
+
+string DumpSymbols::Identifier() {
+  scoped_ptr<FileID> file_id;
+
+  if (from_disk_) {
+    file_id.reset(new FileID(object_filename_.c_str()));
+  } else {
+    file_id.reset(new FileID(contents_.get(), size_));
+  }
+  unsigned char identifier_bytes[16];
+  scoped_ptr<Module> module;
+  if (!selected_object_file_) {
+    if (!CreateEmptyModule(module))
+      return string();
+  }
+  cpu_type_t cpu_type = selected_object_file_->cputype;
+  cpu_subtype_t cpu_subtype = selected_object_file_->cpusubtype;
+  if (!file_id->MachoIdentifier(cpu_type, cpu_subtype, identifier_bytes)) {
+    fprintf(stderr, "Unable to calculate UUID of mach-o binary %s!\n",
+            object_filename_.c_str());
+    return "";
+  }
+
+  char identifier_string[40];
+  FileID::ConvertIdentifierToString(identifier_bytes, identifier_string,
+                                    sizeof(identifier_string));
+
+  string compacted(identifier_string);
+  for(size_t i = compacted.find('-'); i != string::npos;
+      i = compacted.find('-', i))
+    compacted.erase(i, 1);
+
+  // The pdb for these IDs has an extra byte, so to make everything uniform put
+  // a 0 on the end of mac IDs.
+  compacted += "0";
+
+  return compacted;
+}
+
+// A range handler that accepts rangelist data parsed by
+// RangeListReader and populates a range vector (typically
+// owned by a function) with the results.
+class DumpSymbols::DumperRangesHandler:
+      public DwarfCUToModule::RangesHandler {
+ public:
+  DumperRangesHandler(ByteReader* reader) :
+      reader_(reader) { }
+
+  bool ReadRanges(
+      enum DwarfForm form, uint64_t data,
+      RangeListReader::CURangesInfo* cu_info,
+      vector<Module::Range>* ranges) {
+    DwarfRangeListHandler handler(ranges);
+    RangeListReader range_list_reader(reader_, cu_info,
+                                                    &handler);
+    return range_list_reader.ReadRanges(form, data);
+  }
+
+ private:
+  ByteReader* reader_;
+};
+
+// A line-to-module loader that accepts line number info parsed by
+// LineInfo and populates a Module and a line vector
+// with the results.
+class DumpSymbols::DumperLineToModule:
+      public DwarfCUToModule::LineToModuleHandler {
+ public:
+  // Create a line-to-module converter using BYTE_READER.
+  DumperLineToModule(ByteReader* byte_reader)
+      : byte_reader_(byte_reader) { }
+
+  void StartCompilationUnit(const string& compilation_dir) {
+    compilation_dir_ = compilation_dir;
+  }
+
+  void ReadProgram(const uint8_t* program,
+                   uint64_t length,
+                   const uint8_t* string_section,
+                   uint64_t string_section_length,
+                   const uint8_t* line_string_section,
+                   uint64_t line_string_section_length,
+                   Module* module,
+                   vector<Module::Line>* lines,
+                   std::map<uint32_t, Module::File*>* files) {
+    DwarfLineToModule handler(module, compilation_dir_, lines, files);
+    LineInfo parser(program, length, byte_reader_, nullptr, 0,
+                                  nullptr, 0, &handler);
+    parser.Start();
+  }
+ private:
+  string compilation_dir_;
+  ByteReader* byte_reader_;  // WEAK
+};
+
+bool DumpSymbols::CreateEmptyModule(scoped_ptr<Module>& module) {
+  // Select an object file, if SetArchitecture hasn't been called to set one
+  // explicitly.
+  if (!selected_object_file_) {
+    // If there's only one architecture, that's the one.
+    if (object_files_.size() == 1)
+      selected_object_file_ = &object_files_[0];
+    else {
+      // Look for an object file whose architecture matches our own.
+      ArchInfo local_arch = GetLocalArchInfo();
+      if (!SetArchitecture(local_arch)) {
+        fprintf(stderr, "%s: object file contains more than one"
+                " architecture, none of which match the current"
+                " architecture; specify an architecture explicitly"
+                " with '-a ARCH' to resolve the ambiguity\n",
+                object_filename_.c_str());
+        return false;
+      }
+    }
+  }
+
+  assert(selected_object_file_);
+
+  // Find the name of the selected file's architecture, to appear in
+  // the MODULE record and in error messages.
+  const char* selected_arch_name = GetNameFromCPUType(
+      selected_object_file_->cputype, selected_object_file_->cpusubtype);
+
+  // In certain cases, it is possible that architecture info can't be reliably
+  // determined, e.g. new architectures that breakpad is unware of. In that
+  // case, avoid crashing and return false instead.
+  if (selected_arch_name == kUnknownArchName) {
+    return false;
+  }
+
+  if (strcmp(selected_arch_name, "i386") == 0)
+    selected_arch_name = "x86";
+
+  // Produce a name to use in error messages that includes the
+  // filename, and the architecture, if there is more than one.
+  selected_object_name_ = object_filename_;
+  if (object_files_.size() > 1) {
+    selected_object_name_ += ", architecture ";
+    selected_object_name_ + selected_arch_name;
+  }
+
+  // Compute a module name, to appear in the MODULE record.
+  string module_name;
+  if (!module_name_.empty()) {
+    module_name = module_name_;
+  } else {
+    module_name = google_breakpad::BaseName(object_filename_);
+  }
+
+  // Choose an identifier string, to appear in the MODULE record.
+  string identifier = Identifier();
+  if (identifier.empty())
+    return false;
+
+  // Create a module to hold the debugging information.
+  module.reset(new Module(module_name, "mac", selected_arch_name, identifier,
+                          "", enable_multiple_, prefer_extern_name_));
+  return true;
+}
+
+void DumpSymbols::StartProcessSplitDwarf(
+    google_breakpad::CompilationUnit* reader,
+    Module* module,
+    google_breakpad::Endianness endianness,
+    bool handle_inter_cu_refs,
+    bool handle_inline) const {
+  std::string split_file;
+  google_breakpad::SectionMap split_sections;
+  google_breakpad::ByteReader split_byte_reader(endianness);
+  uint64_t cu_offset = 0;
+  if (reader->ProcessSplitDwarf(split_file, split_sections, split_byte_reader,
+                                cu_offset))
+    return;
+  DwarfCUToModule::FileContext file_context(split_file, module,
+                                            handle_inter_cu_refs);
+  for (auto section : split_sections)
+    file_context.AddSectionToSectionMap(section.first, section.second.first,
+                                        section.second.second);
+  // Because DWP/DWO file doesn't have .debug_addr/.debug_line/.debug_line_str,
+  // its debug info will refer to .debug_addr/.debug_line in the main binary.
+  if (file_context.section_map().find(".debug_addr") ==
+      file_context.section_map().end())
+    file_context.AddSectionToSectionMap(".debug_addr", reader->GetAddrBuffer(),
+                                        reader->GetAddrBufferLen());
+  if (file_context.section_map().find(".debug_line") ==
+      file_context.section_map().end())
+    file_context.AddSectionToSectionMap(".debug_line", reader->GetLineBuffer(),
+                                        reader->GetLineBufferLen());
+  if (file_context.section_map().find(".debug_line_str") ==
+      file_context.section_map().end())
+    file_context.AddSectionToSectionMap(".debug_line_str",
+                                        reader->GetLineStrBuffer(),
+                                        reader->GetLineStrBufferLen());
+  DumperRangesHandler ranges_handler(&split_byte_reader);
+  DumperLineToModule line_to_module(&split_byte_reader);
+  DwarfCUToModule::WarningReporter reporter(split_file, cu_offset);
+  DwarfCUToModule root_handler(
+      &file_context, &line_to_module, &ranges_handler, &reporter, handle_inline,
+      reader->GetLowPC(), reader->GetAddrBase(), reader->HasSourceLineInfo(),
+      reader->GetSourceLineOffset());
+  google_breakpad::DIEDispatcher die_dispatcher(&root_handler);
+  google_breakpad::CompilationUnit split_reader(
+      split_file, file_context.section_map(), cu_offset, &split_byte_reader,
+      &die_dispatcher);
+  split_reader.SetSplitDwarf(reader->GetAddrBase(), reader->GetDWOID());
+  split_reader.Start();
+  // Normally, it won't happen unless we have transitive reference.
+  if (split_reader.ShouldProcessSplitDwarf()) {
+    StartProcessSplitDwarf(&split_reader, module, endianness,
+                           handle_inter_cu_refs, handle_inline);
+  }
+}
+
+void DumpSymbols::ReadDwarf(google_breakpad::Module* module,
+                            const mach_o::Reader& macho_reader,
+                            const mach_o::SectionMap& dwarf_sections,
+                            bool handle_inter_cu_refs) const {
+  // Build a byte reader of the appropriate endianness.
+  google_breakpad::Endianness endianness =
+      macho_reader.big_endian() ? ENDIANNESS_BIG : ENDIANNESS_LITTLE;
+  ByteReader byte_reader(endianness);
+
+  // Construct a context for this file.
+  DwarfCUToModule::FileContext file_context(selected_object_name_,
+                                            module,
+                                            handle_inter_cu_refs);
+
+  // Build a SectionMap from our mach_o::SectionMap.
+  for (mach_o::SectionMap::const_iterator it = dwarf_sections.begin();
+       it != dwarf_sections.end(); ++it) {
+    file_context.AddSectionToSectionMap(
+        it->first,
+        it->second.contents.start,
+        it->second.contents.Size());
+  }
+
+  // Find the __debug_info section.
+  SectionMap::const_iterator debug_info_entry =
+      file_context.section_map().find("__debug_info");
+  // There had better be a __debug_info section!
+  if (debug_info_entry == file_context.section_map().end()) {
+    fprintf(stderr, "%s: __DWARF segment of file has no __debug_info section\n",
+            selected_object_name_.c_str());
+    return;
+  }
+  const std::pair<const uint8_t*, uint64_t>& debug_info_section =
+      debug_info_entry->second;
+
+  // Build a line-to-module loader for the root handler to use.
+  DumperLineToModule line_to_module(&byte_reader);
+
+  // .debug_ranges and .debug_rngslists reader
+  DumperRangesHandler ranges_handler(&byte_reader);
+
+  // Walk the __debug_info section, one compilation unit at a time.
+  uint64_t debug_info_length = debug_info_section.second;
+  bool handle_inline = symbol_data_ & INLINES;
+  for (uint64_t offset = 0; offset < debug_info_length;) {
+    // Make a handler for the root DIE that populates MODULE with the
+    // debug info.
+    DwarfCUToModule::WarningReporter reporter(selected_object_name_,
+                                              offset);
+    DwarfCUToModule root_handler(&file_context, &line_to_module,
+                                 &ranges_handler, &reporter, handle_inline);
+    // Make a Dwarf2Handler that drives our DIEHandler.
+    DIEDispatcher die_dispatcher(&root_handler);
+    // Make a DWARF parser for the compilation unit at OFFSET.
+    CompilationUnit dwarf_reader(selected_object_name_,
+                                               file_context.section_map(),
+                                               offset,
+                                               &byte_reader,
+                                               &die_dispatcher);
+    // Process the entire compilation unit; get the offset of the next.
+    offset += dwarf_reader.Start();
+    // Start to process split dwarf file.
+    if (dwarf_reader.ShouldProcessSplitDwarf()) {
+      StartProcessSplitDwarf(&dwarf_reader, module, endianness,
+                             handle_inter_cu_refs, handle_inline);
+    }
+  }
+}
+
+bool DumpSymbols::ReadCFI(google_breakpad::Module* module,
+                          const mach_o::Reader& macho_reader,
+                          const mach_o::Section& section,
+                          bool eh_frame) const {
+  // Find the appropriate set of register names for this file's
+  // architecture.
+  vector<string> register_names;
+  switch (macho_reader.cpu_type()) {
+    case CPU_TYPE_X86:
+      register_names = DwarfCFIToModule::RegisterNames::I386();
+      break;
+    case CPU_TYPE_X86_64:
+      register_names = DwarfCFIToModule::RegisterNames::X86_64();
+      break;
+    case CPU_TYPE_ARM:
+      register_names = DwarfCFIToModule::RegisterNames::ARM();
+      break;
+    case CPU_TYPE_ARM64:
+      register_names = DwarfCFIToModule::RegisterNames::ARM64();
+      break;
+    default: {
+      const char* arch_name = GetNameFromCPUType(macho_reader.cpu_type(),
+                                                 macho_reader.cpu_subtype());
+      fprintf(
+          stderr,
+          "%s: cannot convert DWARF call frame information for architecture "
+          "'%s' (%d, %d) to Breakpad symbol file: no register name table\n",
+          selected_object_name_.c_str(), arch_name, macho_reader.cpu_type(),
+          macho_reader.cpu_subtype());
+      return false;
+    }
+  }
+
+  // Find the call frame information and its size.
+  const uint8_t* cfi = section.contents.start;
+  size_t cfi_size = section.contents.Size();
+
+  // Plug together the parser, handler, and their entourages.
+  DwarfCFIToModule::Reporter module_reporter(selected_object_name_,
+                                             section.section_name);
+  DwarfCFIToModule handler(module, register_names, &module_reporter);
+  ByteReader byte_reader(macho_reader.big_endian() ?
+                                       ENDIANNESS_BIG :
+                                       ENDIANNESS_LITTLE);
+  byte_reader.SetAddressSize(macho_reader.bits_64() ? 8 : 4);
+  // At the moment, according to folks at Apple and some cursory
+  // investigation, Mac OS X only uses DW_EH_PE_pcrel-based pointers, so
+  // this is the only base address the CFI parser will need.
+  byte_reader.SetCFIDataBase(section.address, cfi);
+
+  CallFrameInfo::Reporter dwarf_reporter(selected_object_name_,
+                                                       section.section_name);
+  CallFrameInfo parser(cfi, cfi_size,
+                                     &byte_reader, &handler, &dwarf_reporter,
+                                     eh_frame);
+  parser.Start();
+  return true;
+}
+
+// A LoadCommandHandler that loads whatever debugging data it finds into a
+// Module.
+class DumpSymbols::LoadCommandDumper:
+      public mach_o::Reader::LoadCommandHandler {
+ public:
+  // Create a load command dumper handling load commands from READER's
+  // file, and adding data to MODULE.
+  LoadCommandDumper(const DumpSymbols& dumper,
+                    google_breakpad::Module* module,
+                    const mach_o::Reader& reader,
+                    SymbolData symbol_data,
+                    bool handle_inter_cu_refs)
+      : dumper_(dumper),
+        module_(module),
+        reader_(reader),
+        symbol_data_(symbol_data),
+        handle_inter_cu_refs_(handle_inter_cu_refs) { }
+
+  bool SegmentCommand(const mach_o::Segment& segment);
+  bool SymtabCommand(const ByteBuffer& entries, const ByteBuffer& strings);
+
+ private:
+  const DumpSymbols& dumper_;
+  google_breakpad::Module* module_;  // WEAK
+  const mach_o::Reader& reader_;
+  const SymbolData symbol_data_;
+  const bool handle_inter_cu_refs_;
+};
+
+bool DumpSymbols::LoadCommandDumper::SegmentCommand(const Segment& segment) {
+  mach_o::SectionMap section_map;
+  if (!reader_.MapSegmentSections(segment, &section_map))
+    return false;
+
+  if (segment.name == "__TEXT") {
+    module_->SetLoadAddress(segment.vmaddr);
+    if (symbol_data_ & CFI) {
+      mach_o::SectionMap::const_iterator eh_frame =
+          section_map.find("__eh_frame");
+      if (eh_frame != section_map.end()) {
+        // If there is a problem reading this, don't treat it as a fatal error.
+        dumper_.ReadCFI(module_, reader_, eh_frame->second, true);
+      }
+    }
+    return true;
+  }
+
+  if (segment.name == "__DWARF") {
+    if ((symbol_data_ & SYMBOLS_AND_FILES) || (symbol_data_ & INLINES)) {
+      dumper_.ReadDwarf(module_, reader_, section_map, handle_inter_cu_refs_);
+    }
+    if (symbol_data_ & CFI) {
+      mach_o::SectionMap::const_iterator debug_frame
+          = section_map.find("__debug_frame");
+      if (debug_frame != section_map.end()) {
+        // If there is a problem reading this, don't treat it as a fatal error.
+        dumper_.ReadCFI(module_, reader_, debug_frame->second, false);
+      }
+    }
+  }
+
+  return true;
+}
+
+bool DumpSymbols::LoadCommandDumper::SymtabCommand(const ByteBuffer& entries,
+                                                   const ByteBuffer& strings) {
+  StabsToModule stabs_to_module(module_);
+  // Mac OS X STABS are never "unitized", and the size of the 'value' field
+  // matches the address size of the executable.
+  StabsReader stabs_reader(entries.start, entries.Size(),
+                           strings.start, strings.Size(),
+                           reader_.big_endian(),
+                           reader_.bits_64() ? 8 : 4,
+                           true,
+                           &stabs_to_module);
+  if (!stabs_reader.Process())
+    return false;
+  stabs_to_module.Finalize();
+  return true;
+}
+
+bool DumpSymbols::ReadSymbolData(Module** out_module) {
+  scoped_ptr<Module> module;
+  if (!CreateEmptyModule(module))
+    return false;
+
+  // Parse the selected object file.
+  mach_o::Reader::Reporter reporter(selected_object_name_);
+  mach_o::Reader reader(&reporter);
+  if (!reader.Read(&contents_[0]
+                   + selected_object_file_->offset,
+                   selected_object_file_->size,
+                   selected_object_file_->cputype,
+                   selected_object_file_->cpusubtype))
+    return false;
+
+  // Walk its load commands, and deal with whatever is there.
+  LoadCommandDumper load_command_dumper(*this, module.get(), reader,
+                                        symbol_data_, handle_inter_cu_refs_);
+  if (!reader.WalkLoadCommands(&load_command_dumper))
+    return false;
+
+  *out_module = module.release();
+
+  return true;
+}
+
+// Read the selected object file's debugging information, and write out the
+// header only to |stream|. Return true on success; if an error occurs, report
+// it and return false.
+bool DumpSymbols::WriteSymbolFileHeader(std::ostream& stream) {
+  scoped_ptr<Module> module;
+  if (!CreateEmptyModule(module))
+    return false;
+
+  return module->Write(stream, symbol_data_);
+}
+
+}  // namespace google_breakpad