Breakpad Mac symbol dumper: Unify with Linux dumper; support DWARF CFI.

This patch rewrites the Mac symbol dumper to use the same set of classes
the Linux dumper does for reading debugging information from various
sources, consolidating them into a single table, and writing that out as a
Breakpad symbol file.

In the process, it also adds support for dumping DWARF call frame
information and .eh_frame exception-handling information as Breakpad 'STACK
CFI' records. This allows the Breakpad processor to generate stack traces
from code compiled with -fomit-frame-pointer.

The patch also replaces the DumpSymbols Objective C++ class with
google_breakpad::DumpSymbols, a plain C++ class. The code still uses some
Objective C++ to use the Foundation facilities for dealing with file names
in a file-system-independent fashion, and for examining the contents of
.dSYM bundles.

Since the code has been entirely rewritten, I have changed the author
lines.
A=jimb R=mark

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@614 4c0a9323-5329-0410-9bdc-e9ce6186880e

5 files changed, 640 insertions, 1236 deletions

diff --git a/src/common/mac/dump_syms.h b/src/common/mac/dump_syms.h
index 1acaf44a..f2bee657 100644
--- a/src/common/mac/dump_syms.h
+++ b/src/common/mac/dump_syms.h
@@ -1,4 +1,6 @@
-// Copyright (c) 2006, Google Inc.
+// -*- mode: c++ -*-
+
+// Copyright (c) 2010, Google Inc.
 // All rights reserved.
 //
 // Redistribution and use in source and binary forms, with or without
@@ -27,53 +29,133 @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-// dump_syms.h: Interface for DumpSymbols.  This class will take a mach-o file
-// and extract the symbol information and write it to a file using the
-// breakpad symbol file format.  
+// Author: Jim Blandy <jimb@mozilla.com> <jimb@red-bean.com>
+
+// dump_syms.h: Declaration of google_breakpad::DumpSymbols, a class for
+// reading debugging information from Mach-O files and writing it out as a
+// Breakpad symbol file.
 
-#import <Foundation/Foundation.h>
+#include <Foundation/Foundation.h>
 #include <mach-o/loader.h>
-#include "common/dwarf/dwarf2reader.h"
-
-// This will map from an architecture string to a SectionMap, which
-// will contain the offsets for all the sections in the dictionary
-typedef map<string, dwarf2reader::SectionMap *> ArchSectionMap;
-
-@interface DumpSymbols : NSObject {
- @protected
-  NSString *sourcePath_;              // Source of symbols (STRONG)
-  NSString *architecture_;            // Architecture to extract (STRONG)
-  NSMutableDictionary *addresses_;    // Addresses and symbols (STRONG)
-  NSMutableSet *functionAddresses_;   // Function addresses (STRONG)
-  NSMutableDictionary *sources_;      // Address and Source file paths (STRONG)
-  NSMutableDictionary *headers_;      // Mach-o header information (STRONG)
-  NSMutableDictionary *sectionData_; // Keyed by seg/sect name (STRONG)
-  uint32_t   lastStartAddress_;
-  ArchSectionMap *sectionsForArch_;
-}
-
-- (id)initWithContentsOfFile:(NSString *)machoFile;
-
-- (NSArray *)availableArchitectures;
-
-// One of ppc, x86, i386, ppc64, x86_64
-// If the architecture is not available, it will return NO
-// If not set, the native architecture will be used
-- (BOOL)setArchitecture:(NSString *)architecture;
-- (NSString *)architecture;
-
-// Write the symbols to |symbolFilePath|.  Return YES if successful.
-- (BOOL)writeSymbolFile:(NSString *)symbolFilePath;
-
-@end
-
-@interface MachSection : NSObject {
- @protected
-  struct section *sect_;
-  uint32_t sectionNumber_;
-}
-- (id)initWithMachSection:(struct section *)sect andNumber:(uint32_t)sectionNumber;
-- (struct section*)sectionPointer;
-- (uint32_t)sectionNumber;
-
-@end
+#include <stdio.h>
+#include <stdlib.h>
+
+#include <string>
+#include <vector>
+
+#include "common/byte_cursor.h"
+#include "common/mac/macho_reader.h"
+#include "common/module.h"
+
+namespace google_breakpad {
+
+class DumpSymbols {
+ public:
+  DumpSymbols() 
+      : input_pathname_(),
+        object_filename_(), 
+        contents_(),
+        selected_object_file_(),
+        selected_object_name_() { }
+  ~DumpSymbols() {
+    [input_pathname_ release];
+    [object_filename_ release];
+    [contents_ release];
+  }
+
+  // Prepare to read debugging information from |filename|. |filename| may be
+  // the name of a universal binary, a Mach-O file, or a dSYM bundle
+  // containing either of the above. On success, return true; if there is a
+  // problem reading |filename|, report it and return false.
+  //
+  // (This class uses NSString for filenames and related values,
+  // because the Mac Foundation framework seems to support
+  // filename-related operations more fully on NSString values.)
+  bool Read(NSString *filename);
+
+  // If this dumper's file includes an object file for |cpu_type| and
+  // |cpu_subtype|, then select that object file for dumping, and return
+  // true. Otherwise, return false, and leave this dumper's selected
+  // architecture unchanged.
+  //
+  // By default, if this dumper's file contains only one object file, then
+  // the dumper will dump those symbols; and if it contains more than one
+  // object file, then the dumper will dump the object file whose
+  // architecture matches that of this dumper program.
+  bool SetArchitecture(cpu_type_t cpu_type, cpu_subtype_t cpu_subtype);
+
+  // Return a pointer to an array of 'struct fat_arch' structures,
+  // describing the object files contained in this dumper's file. Set
+  // *|count| to the number of elements in the array. The returned array is
+  // owned by this DumpSymbols instance.
+  //
+  // If there are no available architectures, this function
+  // may return NULL.
+  const struct fat_arch *AvailableArchitectures(size_t *count) {
+    *count = object_files_.size();
+    if (object_files_.size() > 0)
+      return &object_files_[0];
+    return NULL;
+  }
+
+  // Read the selected object file's debugging information, and write it
+  // out to |stream|. Return true on success; if an error occurs, report it
+  // and return false.
+  bool WriteSymbolFile(FILE *stream);
+
+ private:
+  // Used internally.
+  class DumperLineToModule;
+  class LoadCommandDumper;
+
+  // Return an identifier string for the file this DumpSymbols is dumping.
+  std::string Identifier();
+
+  // Read debugging information from |dwarf_sections|, which was taken from
+  // |macho_reader|, and add it to |module|. On success, return true;
+  // on failure, report the problem and return false.
+  bool ReadDwarf(google_breakpad::Module *module,
+                 const mach_o::Reader &macho_reader,
+                 const mach_o::SectionMap &dwarf_sections) const;
+
+  // Read DWARF CFI or .eh_frame data from |section|, belonging to
+  // |macho_reader|, and record it in |module|.  If |eh_frame| is true,
+  // then the data is .eh_frame-format data; otherwise, it is standard DWARF
+  // .debug_frame data. On success, return true; on failure, report
+  // the problem and return false.
+  bool ReadCFI(google_breakpad::Module *module,
+               const mach_o::Reader &macho_reader,
+               const mach_o::Section &section,
+               bool eh_frame) const;
+
+  // The name of the file or bundle whose symbols this will dump.
+  // This is the path given to Read, for use in error messages.
+  NSString *input_pathname_;
+
+  // The name of the file this DumpSymbols will actually read debugging
+  // information from. Normally, this is the same as input_pathname_, but if
+  // filename refers to a dSYM bundle, then this is the resource file
+  // within that bundle.
+  NSString *object_filename_;
+
+  // The complete contents of object_filename_, mapped into memory.
+  NSData *contents_;
+
+  // A vector of fat_arch structures describing the object files
+  // object_filename_ contains. If object_filename_ refers to a fat binary,
+  // this may have more than one element; if it refers to a Mach-O file, this
+  // has exactly one element.
+  vector<struct fat_arch> object_files_;
+
+  // The object file in object_files_ selected to dump, or NULL if 
+  // SetArchitecture hasn't been called yet.
+  const struct fat_arch *selected_object_file_;
+
+  // A string that identifies the selected object file, for use in error
+  // messages.  This is usually object_filename_, but if that refers to a
+  // fat binary, it includes an indication of the particular architecture
+  // within that binary.
+  string selected_object_name_;
+};
+
+}  // namespace google_breakpad
diff --git a/src/common/mac/dump_syms.mm b/src/common/mac/dump_syms.mm
index cf70b1c6..ab2f2b9e 100644
--- a/src/common/mac/dump_syms.mm
+++ b/src/common/mac/dump_syms.mm
@@ -1,4 +1,6 @@
-// Copyright (c) 2006, Google Inc.
+// -*- mode: c++ -*-
+
+// Copyright (c) 2010, Google Inc.
 // All rights reserved.
 //
 // Redistribution and use in source and binary forms, with or without
@@ -27,1196 +29,450 @@
 // (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.mm: Create a symbol file for use with minidumps
 
-#include <unistd.h>
-#include <signal.h>
-#include <cxxabi.h>
-#include <stdlib.h>
+#include "common/mac/dump_syms.h"
 
-#include <mach/machine.h>
+#include <Foundation/Foundation.h>
 #include <mach-o/arch.h>
 #include <mach-o/fat.h>
-#include <mach-o/loader.h>
-#include <mach-o/nlist.h>
-#include <mach-o/stab.h>
-#include <fcntl.h>
-
-#import <Foundation/Foundation.h>
-
-#import "dump_syms.h"
-#import "common/mac/file_id.h"
-#import "common/mac/macho_utilities.h"
-#import "common/dwarf/dwarf2reader.h"
-#import "common/dwarf/functioninfo.h"
-#import "common/dwarf/bytereader.h"
-
+#include <stdio.h>
+
+#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/mac/file_id.h"
+#include "common/mac/macho_reader.h"
+#include "common/module.h"
+#include "common/stabs_reader.h"
+#include "common/stabs_to_module.h"
+
+using dwarf2reader::ByteReader;
+using google_breakpad::DwarfCUToModule;
+using google_breakpad::DwarfLineToModule;
 using google_breakpad::FileID;
-
-static NSString *kAddressSymbolKey = @"symbol";
-static NSString *kAddressConvertedSymbolKey = @"converted_symbol";
-static NSString *kAddressSourceLineKey = @"line";
-static NSString *kFunctionSizeKey = @"size";
-static NSString *kFunctionFileKey = @"source_file";
-static NSString *kHeaderBaseAddressKey = @"baseAddr";
-static NSString *kHeaderSizeKey = @"size";
-static NSString *kHeaderOffsetKey = @"offset";  // Offset to the header
-static NSString *kHeaderIs64BitKey = @"is64";
-static NSString *kHeaderCPUTypeKey = @"cpuType";
-
-// The section for __TEXT, __text seems to be always 1.  This is useful
-// for pruning out extraneous non-function symbols.
-static const int kTextSection = 1;
-
-// Dump FunctionMap to stdout.  Print address, function name, file
-// name, line number, lowpc, and highpc if available.
-void DumpFunctionMap(const dwarf2reader::FunctionMap function_map) {
-  for (dwarf2reader::FunctionMap::const_iterator iter = function_map.begin();
-       iter != function_map.end(); ++iter) {
-    if (iter->second->name.empty()) {
-      continue;
-    }
-    printf("%08llx: %s", iter->first,
-	   iter->second->name.data());
-    if (!iter->second->file.empty()) {
-      printf(" - %s", iter->second->file.data());
-      if (iter->second->line != 0) {
-	printf(":%u", iter->second->line);
-      }
-    }
-    if (iter->second->lowpc != 0 && iter->second->highpc != 0) {
-      printf(" (%08llx - %08llx)\n",
-	     iter->second->lowpc,
-	     iter->second->highpc);
-    }
-  }
-}
-
-
-@interface DumpSymbols(PrivateMethods)
-- (NSString *)convertCPlusPlusSymbol:(NSString *)symbol;
-- (void)addFunction:(NSString *)name line:(int)line address:(uint64_t)address section:(int)section;
-- (BOOL)processSymbolItem:(struct nlist_64 *)list stringTable:(char *)table;
-- (BOOL)loadSymbolInfo:(void *)base offset:(uint32_t)offset;
-- (BOOL)loadSymbolInfo64:(void *)base offset:(uint32_t)offset;
-- (BOOL)loadSymbolInfoForArchitecture;
-- (BOOL)loadDWARFSymbolInfo:(void *)base offset:(uint32_t)offset;
-- (BOOL)loadSTABSSymbolInfo:(void *)base offset:(uint32_t)offset;
-- (void)generateSectionDictionary:(struct mach_header*)header;
-- (BOOL)loadHeader:(void *)base offset:(uint32_t)offset;
-- (BOOL)loadHeader64:(void *)base offset:(uint32_t)offset;
-- (BOOL)loadModuleInfo;
-- (void)processDWARFLineNumberInfo:(dwarf2reader::LineMap*)line_map;
-- (void)processDWARFFunctionInfo:(dwarf2reader::FunctionMap*)address_to_funcinfo;
-- (void)processDWARFSourceFileInfo:(vector<dwarf2reader::SourceFileInfo>*) files;
-- (BOOL)loadSymbolInfo:(void *)base offset:(uint32_t)offset;
-- (dwarf2reader::SectionMap*)getSectionMapForArchitecture:(NSString*)architecture;
-@end
-
-@implementation DumpSymbols
-//=============================================================================
-- (NSString *)convertCPlusPlusSymbol:(NSString *)symbol {
-  // __cxa_demangle will realloc this if needed
-  char *buffer = (char *)malloc(1024);
-  size_t buffer_size = 1024;
-  int result;
-
-  const char *sym = [symbol UTF8String];
-  NSString *demangled = nil;
-  buffer = abi::__cxa_demangle(sym, buffer, &buffer_size, &result);
-  if (result == 0) {
-    demangled = [NSString stringWithUTF8String:buffer];
-  }
-  free(buffer);
-  return demangled;
-}
-
-//=============================================================================
-- (void)addFunction:(NSString *)name line:(int)line address:(uint64_t)address section:(int)section {
-  NSNumber *addressNum = [NSNumber numberWithUnsignedLongLong:address];
-
-  if (!address)
-    return;
-
-  // If the function starts with "_Z" or "__Z" then demangle it.
-  BOOL isCPP = NO;
-
-  if ([name hasPrefix:@"__Z"]) {
-    // Remove the leading underscore
-    name = [name substringFromIndex:1];
-    isCPP = YES;
-  } else if ([name hasPrefix:@"_Z"]) {
-    isCPP = YES;
-  }
-
-  // Filter out non-functions
-  if ([name hasSuffix:@".eh"])
-    return;
-
-  if ([name hasSuffix:@"__func__"])
-    return;
-
-  if ([name hasSuffix:@"GCC_except_table"])
-    return;
-
-  if (isCPP) {
-    // OBJCPP_MANGLING_HACK
-    // There are cases where ObjC++ mangles up an ObjC name using quasi-C++ 
-    // mangling:
-    // @implementation Foozles + (void)barzles {
-    //    static int Baz = 0;
-    // } @end
-    // gives you _ZZ18+[Foozles barzles]E3Baz
-    // c++filt won't parse this properly, and will crash in certain cases. 
-    // Logged as radar:
-    // 5129938: c++filt does not deal with ObjC++ symbols
-    // If 5129938 ever gets fixed, we can remove this, but for now this prevents
-    // c++filt from attempting to demangle names it doesn't know how to handle.
-    // This is with c++filt 2.16
-    NSCharacterSet *objcppCharSet = [NSCharacterSet characterSetWithCharactersInString:@"-+[]: "];
-    NSRange emptyRange = { NSNotFound, 0 };
-    NSRange objcppRange = [name rangeOfCharacterFromSet:objcppCharSet];
-    isCPP = NSEqualRanges(objcppRange, emptyRange);
-  } else if ([name characterAtIndex:0] == '_') {
-    // Remove the leading underscore
-    name = [name substringFromIndex:1];
-  }
-
-  // If there's already an entry for this address, check and see if we can add
-  // either the symbol, or a missing line #
-  NSMutableDictionary *dict = [addresses_ objectForKey:addressNum];
-
-  if (!dict) {
-    dict = [[NSMutableDictionary alloc] init];
-    [addresses_ setObject:dict forKey:addressNum];
-    [dict release];
-  }
-
-  if (name && ![dict objectForKey:kAddressSymbolKey]) {
-    [dict setObject:name forKey:kAddressSymbolKey];
-
-    // only functions, not line number addresses
-    [functionAddresses_ addObject:addressNum];
-  }
-
-  if (isCPP) {
-    // try demangling
-    NSString *demangled = [self convertCPlusPlusSymbol:name];
-    if (demangled != nil)
-      [dict setObject:demangled forKey:kAddressConvertedSymbolKey];
-  }
-  
-  if (line && ![dict objectForKey:kAddressSourceLineKey])
-    [dict setObject:[NSNumber numberWithUnsignedInt:line]
-             forKey:kAddressSourceLineKey];
-
-}
-
-//=============================================================================
-- (BOOL)processSymbolItem:(struct nlist_64 *)list stringTable:(char *)table {
-  uint32_t n_strx = list->n_un.n_strx;
-  BOOL result = NO;
-
-  // We don't care about non-section specific information except function length
-  if (list->n_sect == 0 && list->n_type != N_FUN )
-    return NO;
-
-  if (list->n_type == N_FUN) {
-    if (list->n_sect != 0) {
-      // we get the function address from the first N_FUN
-      lastStartAddress_ = list->n_value;
-    }
-    else {
-      // an N_FUN from section 0 may follow the initial N_FUN
-      // giving us function length information
-      NSMutableDictionary *dict = [addresses_ objectForKey:
-        [NSNumber numberWithUnsignedLong:lastStartAddress_]];
-      
-      assert(dict);
-
-      // only set the function size the first time
-      // (sometimes multiple section 0 N_FUN entries appear!)
-      if (![dict objectForKey:kFunctionSizeKey]) {
-        [dict setObject:[NSNumber numberWithUnsignedLongLong:list->n_value]
-                 forKey:kFunctionSizeKey];
-      }
-    }
-  }
-  
-  int line = list->n_desc;
-  
-  // __TEXT __text section
-  NSMutableDictionary *archSections = [sectionData_ objectForKey:architecture_];
-
-  uint32_t mainSection = [[archSections objectForKey:@"__TEXT__text" ] sectionNumber];
-
-  // Extract debugging information:
-  // Doc: http://developer.apple.com/documentation/DeveloperTools/gdb/stabs/stabs_toc.html
-  // Header: /usr/include/mach-o/stab.h:
-  if (list->n_type == N_SO)  {
-    NSString *src = [NSString stringWithUTF8String:&table[n_strx]];
-    NSString *ext = [src pathExtension];
-    NSNumber *address = [NSNumber numberWithUnsignedLongLong:list->n_value];
-
-    // Leopard puts .c files with no code as an offset of 0, but a
-    // crash can't happen here and it throws off our code that matches
-    // symbols to line numbers so we ignore them..
-    // Return YES because this isn't an error, just something we don't
-    // care to handle.
-    if ([address unsignedLongValue] == 0) {
-      return YES;
-    }
-    // TODO(waylonis):Ensure that we get the full path for the source file
-    // from the first N_SO record
-    // If there is an extension, we'll consider it source code
-    if ([ext length]) {
-      if (!sources_)
-        sources_ = [[NSMutableDictionary alloc] init];
-      // Save the source associated with an address
-      [sources_ setObject:src forKey:address];
-      result = YES;
-    }
-  } else if (list->n_type == N_FUN) {
-    NSString *fn = [NSString stringWithUTF8String:&table[n_strx]];
-    NSRange range = [fn rangeOfString:@":" options:NSBackwardsSearch];
-
-    if (![fn length])
-      return NO;
-
-    if (range.length > 0) {
-      // The function has a ":" followed by some stuff, so strip it off
-      fn = [fn substringToIndex:range.location];
-    }
+using google_breakpad::mach_o::FatReader;
+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 std::make_pair;
+using std::pair;
+using std::string;
+using std::vector;
+
+namespace google_breakpad {
+
+bool DumpSymbols::Read(NSString *filename) {
+  if (![[NSFileManager defaultManager] fileExistsAtPath:filename]) {
+    fprintf(stderr, "Object file does not exist: %s\n",
+	    [filename fileSystemRepresentation]);
+    return false;
+  }
+
+  input_pathname_ = [filename retain];
+
+  // Does this filename refer to a dSYM bundle?
+  NSBundle *bundle = [NSBundle bundleWithPath:input_pathname_];
+
+  if (bundle) {
+    // Filenames referring to bundles usually have names of the form
+    // "<basename>.dSYM"; however, if the user has specified a wrapper
+    // suffix (the WRAPPER_SUFFIX and WRAPPER_EXTENSION build settings),
+    // then the name may have the form "<basename>.<extension>.dSYM". In
+    // either case, the resource name for the file containing the DWARF
+    // info within the bundle is <basename>.
+    //
+    // Since there's no way to tell how much to strip off, remove one
+    // extension at a time, and use the first one that
+    // pathForResource:ofType:inDirectory likes.
+    NSString *base_name = [input_pathname_ lastPathComponent];
+    NSString *dwarf_resource;
     
-    [self addFunction:fn line:line address:list->n_value section:list->n_sect ];
-
-    result = YES;
-  } else if (list->n_type == N_SLINE && list->n_sect == mainSection) {
-    [self addFunction:nil line:line address:list->n_value section:list->n_sect ];
-    result = YES;
-  } else if (((list->n_type & N_TYPE) == N_SECT) && !(list->n_type & N_STAB)) {
-    // Regular symbols or ones that are external
-    NSString *fn = [NSString stringWithUTF8String:&table[n_strx]];
-
-    [self addFunction:fn line:0 address:list->n_value section:list->n_sect ];
-    result = YES;
-  }
-
-  return result;
-}
-
-#define SwapLongLongIfNeeded(a) (swap ? NXSwapLongLong(a) : (a))
-#define SwapLongIfNeeded(a) (swap ? NXSwapLong(a) : (a))
-#define SwapIntIfNeeded(a) (swap ? NXSwapInt(a) : (a))
-#define SwapShortIfNeeded(a) (swap ? NXSwapShort(a) : (a))
-
-//=============================================================================
-- (BOOL)loadSymbolInfo:(void *)base offset:(uint32_t)offset {
-  BOOL loadedStabs = [self loadSTABSSymbolInfo:base offset:offset];
-
-  NSMutableDictionary *archSections = [sectionData_ objectForKey:architecture_];
-  BOOL loadedDWARF = NO;
-  if ([archSections objectForKey:@"__DWARF__debug_info"]) {
-    // Treat this this as debug information
-    loadedDWARF = [self loadDWARFSymbolInfo:base offset:offset];
-  }
-
-  return loadedDWARF || loadedStabs;
-}
-
-//=============================================================================
-- (BOOL)loadDWARFSymbolInfo:(void *)base offset:(uint32_t)offset {
-
-  struct mach_header *header = (struct mach_header *) 
-    ((uint32_t)base + offset);
-  BOOL swap = (header->magic == MH_CIGAM);
-
-  NSMutableDictionary *archSections = [sectionData_ objectForKey:architecture_];
-  assert (archSections != nil);
-  section *dbgInfoSection = [[archSections objectForKey:@"__DWARF__debug_info"] sectionPointer];
-  uint32_t debugInfoSize = SwapLongIfNeeded(dbgInfoSection->size);
-
-#if __BIG_ENDIAN__
-  dwarf2reader::ByteReader byte_reader(swap ?
-                                       dwarf2reader::ENDIANNESS_LITTLE :
-                                       dwarf2reader::ENDIANNESS_BIG);
-#elif __LITTLE_ENDIAN__
-  dwarf2reader::ByteReader byte_reader(swap ?
-                                       dwarf2reader::ENDIANNESS_BIG :
-                                       dwarf2reader::ENDIANNESS_LITTLE);
-#endif
-  uint64_t dbgOffset = 0;
-
-  dwarf2reader::SectionMap* oneArchitectureSectionMap = [self getSectionMapForArchitecture:architecture_];
-
-  while (dbgOffset < debugInfoSize) {
-    // Prepare necessary objects.
-    dwarf2reader::FunctionMap off_to_funcinfo;
-    dwarf2reader::FunctionMap address_to_funcinfo;
-    dwarf2reader::LineMap line_map;
-    vector<dwarf2reader::SourceFileInfo> files;
-    vector<string> dirs;
-
-    dwarf2reader::CULineInfoHandler line_info_handler(&files, &dirs,
-						      &line_map);
-
-    dwarf2reader::CUFunctionInfoHandler function_info_handler(&files, &dirs,
-                                                              &line_map,
-                                                              &off_to_funcinfo,
-                                                              &address_to_funcinfo,
-							      &line_info_handler,
-                                                              *oneArchitectureSectionMap,
-                                                              &byte_reader);
-
-    dwarf2reader::CompilationUnit compilation_unit(*oneArchitectureSectionMap,
-                                                   dbgOffset,
-                                                   &byte_reader,
-                                                   &function_info_handler);
-
-    dbgOffset += compilation_unit.Start();
-
-    // The next 3 functions take the info that the dwarf reader
-    // gives and massages them into the data structures that
-    // dump_syms uses 
-    [self processDWARFSourceFileInfo:&files];
-    [self processDWARFFunctionInfo:&address_to_funcinfo];
-    [self processDWARFLineNumberInfo:&line_map];
-  }
-
-  return YES;
-}
-
-- (void)processDWARFSourceFileInfo:(vector<dwarf2reader::SourceFileInfo>*) files {
-  if (!sources_)
-    sources_ = [[NSMutableDictionary alloc] init];
-  // Save the source associated with an address
-  vector<dwarf2reader::SourceFileInfo>::const_iterator iter = files->begin();
-  for (; iter != files->end(); iter++) {
-    NSString *sourceFile = [NSString stringWithUTF8String:(*iter).name.c_str()];
-    if ((*iter).lowpc != ULLONG_MAX) {
-      NSNumber *address = [NSNumber numberWithUnsignedLongLong:(*iter).lowpc];
-      if ([address unsignedLongLongValue] == 0) {
-        continue;
-      }
-      [sources_ setObject:sourceFile forKey:address];
-    }
-  }
-}
-  
-- (void)processDWARFFunctionInfo:(dwarf2reader::FunctionMap*)address_to_funcinfo {
-  for (dwarf2reader::FunctionMap::const_iterator iter = address_to_funcinfo->begin();
-       iter != address_to_funcinfo->end(); ++iter) {
-    if (iter->second->name.empty()) {
-      continue;
-    }
-
-    if (!addresses_)
-      addresses_ = [[NSMutableDictionary alloc] init];
-
-    NSNumber *addressNum = [NSNumber numberWithUnsignedLongLong:(*iter).second->lowpc];
-	
-    [functionAddresses_ addObject:addressNum];
-
-    NSMutableDictionary *dict = [addresses_ objectForKey:addressNum];
-
-    if (!dict) {
-      dict = [[NSMutableDictionary alloc] init];
-      [addresses_ setObject:dict forKey:addressNum];
-      [dict release];
-    }
-
-    // set name of function if it isn't already set
-    if (![dict objectForKey:kAddressSymbolKey]) {
-      NSString *symbolName = [NSString stringWithUTF8String:iter->second->name.c_str()];
-      [dict setObject:symbolName forKey:kAddressSymbolKey];
-    }
-
-    // try demangling function name if we have a mangled name
-    if (![dict objectForKey:kAddressConvertedSymbolKey] &&
-        !iter->second->mangled_name.empty()) {
-      NSString *mangled = [NSString stringWithUTF8String:iter->second->mangled_name.c_str()];
-      NSString *demangled = [self convertCPlusPlusSymbol:mangled];
-      if (demangled != nil)
-        [dict setObject:demangled forKey:kAddressConvertedSymbolKey];
-    }
-  
-    // set line number for beginning of function
-    if (iter->second->line && ![dict objectForKey:kAddressSourceLineKey])
-      [dict setObject:[NSNumber numberWithUnsignedInt:iter->second->line]
-	    forKey:kAddressSourceLineKey];
-
-    // set function size by subtracting low PC from high PC
-    if (![dict objectForKey:kFunctionSizeKey]) {
-      [dict setObject:[NSNumber numberWithUnsignedLongLong:iter->second->highpc - iter->second->lowpc]
-	    forKey:kFunctionSizeKey];
-    }
-
-    // Set the file that the function is in
-    if (![dict objectForKey:kFunctionFileKey]) {
-      [dict setObject:[NSString stringWithUTF8String:iter->second->file.c_str()]
-               forKey:kFunctionFileKey];
-    }
-  }
-}
-
-- (void)processDWARFLineNumberInfo:(dwarf2reader::LineMap*)line_map {
-  for (dwarf2reader::LineMap::const_iterator iter = line_map->begin();
-       iter != line_map->end(); 
-       ++iter) {
-
-    NSNumber *addressNum = [NSNumber numberWithUnsignedLongLong:iter->first];
-    NSMutableDictionary *dict = [addresses_ objectForKey:addressNum];
-
-    if (!dict) {
-      dict = [[NSMutableDictionary alloc] init];
-      [addresses_ setObject:dict forKey:addressNum];
-      [dict release];
-    } 
-	
-    if (iter->second.second && ![dict objectForKey:kAddressSourceLineKey]) {
-      [dict setObject:[NSNumber numberWithUnsignedInt:iter->second.second]
-	    forKey:kAddressSourceLineKey];
-    }
-
-    // Set the file that the function's address is in
-    if (![dict objectForKey:kFunctionFileKey]) {
-      [dict setObject:[NSString stringWithUTF8String:iter->second.first.c_str()]
-               forKey:kFunctionFileKey];
-    }
-  }
-}
-
-//=============================================================================
-- (BOOL)loadSTABSSymbolInfo:(void *)base offset:(uint32_t)offset {
-  struct mach_header *header = (struct mach_header *)((uint32_t)base + offset);
-  BOOL swap = (header->magic == MH_CIGAM);
-  uint32_t count = SwapLongIfNeeded(header->ncmds);
-  struct load_command *cmd =
-    (struct load_command *)((uint32_t)header + sizeof(struct mach_header));
-  uint32_t symbolTableCommand = SwapLongIfNeeded(LC_SYMTAB);
-  BOOL result = NO;
-
-  if (!addresses_)
-    addresses_ = [[NSMutableDictionary alloc] init];
-
-  for (uint32_t i = 0; cmd && (i < count); ++i) {
-    if (cmd->cmd == symbolTableCommand) {
-      struct symtab_command *symtab = (struct symtab_command *)cmd;
-      uint32_t ncmds = SwapLongIfNeeded(symtab->nsyms);
-      uint32_t symoff = SwapLongIfNeeded(symtab->symoff);
-      uint32_t stroff = SwapLongIfNeeded(symtab->stroff);
-      struct nlist *list = (struct nlist *)((uint32_t)base + symoff + offset);
-      char *strtab = ((char *)header + stroff);
-
-      // Process each command, looking for debugging stuff
-      for (uint32_t j = 0; j < ncmds; ++j, ++list) {
-        // Fill in an nlist_64 structure and process with that
-        struct nlist_64 nlist64;
-        nlist64.n_un.n_strx = SwapLongIfNeeded(list->n_un.n_strx);
-        nlist64.n_type = list->n_type;
-        nlist64.n_sect = list->n_sect;
-        nlist64.n_desc = SwapShortIfNeeded(list->n_desc);
-        nlist64.n_value = (uint64_t)SwapLongIfNeeded(list->n_value);
-
-        // TODO(nealsid): is this broken? we get NO if one symbol fails
-        // but then we lose that information if another suceeeds
-        if ([self processSymbolItem:&nlist64 stringTable:strtab])
-          result = YES;
+    do {
+      NSString *new_base_name = [base_name stringByDeletingPathExtension];
+
+      // If stringByDeletingPathExtension returned the name unchanged, then
+      // there's nothing more for us to strip off --- lose.
+      if ([new_base_name isEqualToString:base_name]) {
+	fprintf(stderr, "Unable to find DWARF-bearing file in bundle: %s\n",
+		[input_pathname_ fileSystemRepresentation]);
+        return false;
       }
-    }
-
-    uint32_t cmdSize = SwapLongIfNeeded(cmd->cmdsize);
-    cmd = (struct load_command *)((uint32_t)cmd + cmdSize);
-  }
-
-  return result;
-}
-
-//=============================================================================
-- (BOOL)loadSymbolInfo64:(void *)base offset:(uint32_t)offset {
-  struct mach_header_64 *header = (struct mach_header_64 *)
-    ((uint32_t)base + offset);
-  BOOL swap = (header->magic == MH_CIGAM_64);
-  uint32_t count = SwapLongIfNeeded(header->ncmds);
-  struct load_command *cmd =
-    (struct load_command *)((uint32_t)header + sizeof(struct mach_header));
-  uint32_t symbolTableCommand = SwapLongIfNeeded(LC_SYMTAB);
-  BOOL result = NO;
 
-  for (uint32_t i = 0; cmd && (i < count); i++) {
-    if (cmd->cmd == symbolTableCommand) {
-      struct symtab_command *symtab = (struct symtab_command *)cmd;
-      uint32_t ncmds = SwapLongIfNeeded(symtab->nsyms);
-      uint32_t symoff = SwapLongIfNeeded(symtab->symoff);
-      uint32_t stroff = SwapLongIfNeeded(symtab->stroff);
-      struct nlist_64 *list = (struct nlist_64 *)((uint32_t)base + symoff);
-      char *strtab = ((char *)header + stroff);
+      // Take the shortened result as our new base_name.
+      base_name = new_base_name;
 
-      // Process each command, looking for debugging stuff
-      for (uint32_t j = 0; j < ncmds; ++j, ++list) {
-        if (!(list->n_type & (N_STAB | N_TYPE)))
-          continue;
+      // Try to find a DWARF resource in the bundle under the new base_name.
+      dwarf_resource = [bundle pathForResource:base_name
+                        ofType:nil inDirectory:@"DWARF"];
+    } while (!dwarf_resource);
 
-        // Fill in an nlist_64 structure and process with that
-        struct nlist_64 nlist64;
-        nlist64.n_un.n_strx = SwapLongIfNeeded(list->n_un.n_strx);
-        nlist64.n_type = list->n_type;
-        nlist64.n_sect = list->n_sect;
-        nlist64.n_desc = SwapShortIfNeeded(list->n_desc);
-        nlist64.n_value = SwapLongLongIfNeeded(list->n_value);
-
-        if ([self processSymbolItem:&nlist64 stringTable:strtab])
-          result = YES;
-      }
-    }
-
-    uint32_t cmdSize = SwapLongIfNeeded(cmd->cmdsize);
-    cmd = (struct load_command *)((uint32_t)cmd + cmdSize);
-  }
-
-  return result;
-}
-
-//=============================================================================
-- (BOOL)loadSymbolInfoForArchitecture {
-  NSMutableData *data = [[NSMutableData alloc]
-    initWithContentsOfMappedFile:sourcePath_];
-
-  NSDictionary *headerInfo = [headers_ objectForKey:architecture_];
-  void *base = [data mutableBytes];
-  uint32_t offset =
-    [[headerInfo objectForKey:kHeaderOffsetKey] unsignedLongValue];
-  BOOL is64 = [[headerInfo objectForKey:kHeaderIs64BitKey] boolValue];
-  BOOL result = is64 ? [self loadSymbolInfo64:base offset:offset] :
-    [self loadSymbolInfo:base offset:offset];
-
-  [data release];
-  return result;
-}
-
-- (dwarf2reader::SectionMap*)getSectionMapForArchitecture:(NSString*)architecture {
-
-  string currentArch([architecture UTF8String]);
-  dwarf2reader::SectionMap *oneArchitectureSectionMap;
-
-  ArchSectionMap::const_iterator iter = sectionsForArch_->find(currentArch);
-  
-  if (iter == sectionsForArch_->end()) {
-    oneArchitectureSectionMap = new dwarf2reader::SectionMap();
-    sectionsForArch_->insert(make_pair(currentArch, oneArchitectureSectionMap));
+    object_filename_ = [dwarf_resource retain];
   } else {
-    oneArchitectureSectionMap = iter->second;
-  }
-    
-  return oneArchitectureSectionMap;
+    object_filename_ = [input_pathname_ retain];
+  }
+
+  // Read the file's contents into memory.
+  //
+  // The documentation for dataWithContentsOfMappedFile says:
+  //
+  //     Because of file mapping restrictions, this method should only be
+  //     used if the file is guaranteed to exist for the duration of the
+  //     data object’s existence. It is generally safer to use the
+  //     dataWithContentsOfFile: method.
+  //
+  // I gather this means that OS X doesn't have (or at least, that method
+  // doesn't use) a form of mapping like Linux's MAP_PRIVATE, where the
+  // process appears to get its own copy of the data, and changes to the
+  // file don't affect memory and vice versa).
+  NSError *error;
+  contents_ = [NSData dataWithContentsOfFile:object_filename_
+	                             options:0
+	                               error:&error];
+  if (!contents_) {
+    fprintf(stderr, "Error reading object file: %s: %s\n",
+	    [object_filename_ fileSystemRepresentation],
+	    [[error localizedDescription] UTF8String]);
+    return false;
+  }
+  [contents_ retain];
+
+  // Get the list of object files present in the file.
+  FatReader::Reporter fat_reporter([object_filename_
+                                    fileSystemRepresentation]);
+  FatReader fat_reader(&fat_reporter);
+  if (!fat_reader.Read(reinterpret_cast<const uint8_t *>([contents_ bytes]),
+                       [contents_ length])) {
+    return false;
+  }
+
+  // Get our own copy of fat_reader's object file list.
+  size_t object_files_count;
+  const struct fat_arch *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_ fileSystemRepresentation]);
+    return false;
+  }
+  object_files_.resize(object_files_count);
+  memcpy(&object_files_[0], object_files,
+         sizeof(struct fat_arch) * object_files_count);
+
+  return true;
 }
 
-//=============================================================================
-// build a dictionary of section numbers keyed off a string
-// which is the concatenation of the segment name and the section name
-- (void)generateSectionDictionary:(struct mach_header*)header {
-
-  BOOL swap = (header->magic == MH_CIGAM);
-  uint32_t count = SwapLongIfNeeded(header->ncmds);
-  struct load_command *cmd =
-    (struct load_command *)((uint32_t)header + sizeof(struct mach_header));
-  uint32_t segmentCommand = SwapLongIfNeeded(LC_SEGMENT);
-  uint32_t sectionNumber = 1;   // section numbers are counted from 1
-  
-  cpu_type_t cpu = SwapIntIfNeeded(header->cputype);
-
-  NSString *arch;
-
-  if (cpu & CPU_ARCH_ABI64)
-    arch = ((cpu & ~CPU_ARCH_ABI64) == CPU_TYPE_X86) ?
-      @"x86_64" : @"ppc64";
-  else
-    arch = (cpu == CPU_TYPE_X86) ? @"x86" : @"ppc";
-
-  NSMutableDictionary *archSections;
-
-  if (!sectionData_) {
-    sectionData_ = [[NSMutableDictionary alloc] init];
-  }
-  
-  if (![sectionData_ objectForKey:architecture_]) {
-    [sectionData_ setObject:[[NSMutableDictionary alloc] init] forKey:arch];
-  }
-
-  archSections = [sectionData_ objectForKey:arch];
-
-  dwarf2reader::SectionMap* oneArchitectureSectionMap = [self getSectionMapForArchitecture:arch];
-  
-  // loop through every segment command, then through every section
-  // contained inside each of them
-  for (uint32_t i = 0; cmd && (i < count); ++i) {
-    if (cmd->cmd == segmentCommand) {            
-      struct segment_command *seg = (struct segment_command *)cmd;
-      section *sect = (section *)((uint32_t)cmd + sizeof(segment_command));
-      uint32_t nsects = SwapLongIfNeeded(seg->nsects);
-      
-      for (uint32_t j = 0; j < nsects; ++j) {
-        NSString *segSectName = [NSString stringWithFormat:@"%s%s",
-          seg->segname, sect->sectname];
-        
-        [archSections setObject:[[MachSection alloc] initWithMachSection:sect andNumber:sectionNumber]
-		      forKey:segSectName];
-
-	// filter out sections with size 0, offset 0
-	if (sect->offset != 0 && sect->size != 0) {
-	  // fill sectionmap for dwarf reader
-	  oneArchitectureSectionMap->insert(make_pair(sect->sectname,make_pair(((const char*)header) + SwapLongIfNeeded(sect->offset), (size_t)SwapLongIfNeeded(sect->size))));
-	}
-
-        ++sect;
-        ++sectionNumber;
-      }
-    }
-
-    uint32_t cmdSize = SwapLongIfNeeded(cmd->cmdsize);
-    cmd = (struct load_command *)((uint32_t)cmd + cmdSize);
-  }
+bool DumpSymbols::SetArchitecture(cpu_type_t cpu_type,
+                                  cpu_subtype_t cpu_subtype) {
+  // Find the best match for the architecture the user requested.
+  const struct fat_arch *best_match
+    = NXFindBestFatArch(cpu_type, cpu_subtype, &object_files_[0],
+                        object_files_.size());
+  if (!best_match) return false;
+
+  // Record the selected object file.
+  selected_object_file_ = best_match;
+  return true;
 }
 
-//=============================================================================
-- (BOOL)loadHeader:(void *)base offset:(uint32_t)offset {
-  struct mach_header *header = (struct mach_header *)((uint32_t)base + offset);
-  BOOL swap = (header->magic == MH_CIGAM);
-  uint32_t count = SwapLongIfNeeded(header->ncmds);
-  struct load_command *cmd =
-    (struct load_command *)((uint32_t)header + sizeof(struct mach_header));
-  uint32_t segmentCommand = SwapLongIfNeeded(LC_SEGMENT);
-
-  [self generateSectionDictionary:header];
-
-  for (uint32_t i = 0; cmd && (i < count); ++i) {
-    if (cmd->cmd == segmentCommand) {
-      struct segment_command *seg = (struct segment_command *)cmd;
-      
-      if (!strcmp(seg->segname, "__TEXT")) {
-        uint32_t addr = SwapLongIfNeeded(seg->vmaddr);
-        uint32_t size = SwapLongIfNeeded(seg->vmsize);
-        cpu_type_t cpu = SwapIntIfNeeded(header->cputype);
-        NSString *cpuStr = (cpu == CPU_TYPE_I386) ? @"x86" : @"ppc";
-
-        [headers_ setObject:[NSDictionary dictionaryWithObjectsAndKeys:
-          [NSNumber numberWithUnsignedLongLong:(uint64_t)addr],
-          kHeaderBaseAddressKey,
-          [NSNumber numberWithUnsignedLongLong:(uint64_t)size], kHeaderSizeKey,
-          [NSNumber numberWithUnsignedLong:offset], kHeaderOffsetKey,
-          [NSNumber numberWithBool:NO], kHeaderIs64BitKey,
-          [NSNumber numberWithUnsignedLong:cpu], kHeaderCPUTypeKey,
-          nil] forKey:cpuStr];
-
-        return YES;
-      }
-    }
-
-    uint32_t cmdSize = SwapLongIfNeeded(cmd->cmdsize);
-    cmd = (struct load_command *)((uint32_t)cmd + cmdSize);
+string DumpSymbols::Identifier() {
+  FileID file_id([object_filename_ fileSystemRepresentation]);
+  unsigned char identifier_bytes[16];
+  cpu_type_t cpu_type = selected_object_file_->cputype;
+  if (!file_id.MachoIdentifier(cpu_type, identifier_bytes)) {
+    fprintf(stderr, "Unable to calculate UUID of mach-o binary %s!\n",
+	    [object_filename_ fileSystemRepresentation]);
+    return "";
   }
 
-  return NO;
-}
-
-//=============================================================================
-- (BOOL)loadHeader64:(void *)base offset:(uint32_t)offset {
-  struct mach_header_64 *header =
-    (struct mach_header_64 *)((uint32_t)base + offset);
-  BOOL swap = (header->magic == MH_CIGAM_64);
-  uint32_t count = SwapLongIfNeeded(header->ncmds);
-  struct load_command *cmd =
-    (struct load_command *)((uint32_t)header + sizeof(struct mach_header_64));
-
-  for (uint32_t i = 0; cmd && (i < count); ++i) {
-    uint32_t segmentCommand = SwapLongIfNeeded(LC_SEGMENT_64);
-    if (cmd->cmd == segmentCommand) {
-      struct segment_command_64 *seg = (struct segment_command_64 *)cmd;
-      if (!strcmp(seg->segname, "__TEXT")) {
-        uint64_t addr = SwapLongLongIfNeeded(seg->vmaddr);
-        uint64_t size = SwapLongLongIfNeeded(seg->vmsize);
-        cpu_type_t cpu = SwapIntIfNeeded(header->cputype);
-        cpu &= (~CPU_ARCH_ABI64);
-        NSString *cpuStr = (cpu == CPU_TYPE_I386) ? @"x86_64" : @"ppc64";
-
-        [headers_ setObject:[NSDictionary dictionaryWithObjectsAndKeys:
-          [NSNumber numberWithUnsignedLongLong:addr], kHeaderBaseAddressKey,
-          [NSNumber numberWithUnsignedLongLong:size], kHeaderSizeKey,
-          [NSNumber numberWithUnsignedLong:offset], kHeaderOffsetKey,
-          [NSNumber numberWithBool:YES], kHeaderIs64BitKey,
-          [NSNumber numberWithUnsignedLong:cpu], kHeaderCPUTypeKey,
-          nil] forKey:cpuStr];
-        return YES;
-      }
-    }
+  char identifier_string[40];
+  FileID::ConvertIdentifierToString(identifier_bytes, identifier_string,
+                                    sizeof(identifier_string));
 
-    uint32_t cmdSize = SwapLongIfNeeded(cmd->cmdsize);
-    cmd = (struct load_command *)((uint32_t)cmd + cmdSize);
-  }
+  string compacted(identifier_string);
+  for(size_t i = compacted.find('-'); i != string::npos;
+      i = compacted.find('-', i))
+    compacted.erase(i, 1);
 
-  return NO;
+  return compacted;
 }
 
-//=============================================================================
-- (BOOL)loadModuleInfo {
-  uint64_t result = 0;
-  NSMutableData *data = [[NSMutableData alloc]
-    initWithContentsOfMappedFile:sourcePath_];
-  void *bytes = [data mutableBytes];
-  struct fat_header *fat = (struct fat_header *)bytes;
-
-  if (!fat) {
-    [data release];
-    return 0;
-  }
-
-  // Gather some information based on the header
-  BOOL isFat = fat->magic == FAT_MAGIC || fat->magic == FAT_CIGAM;
-  BOOL is64 = fat->magic == MH_MAGIC_64 || fat->magic == MH_CIGAM_64;
-  BOOL is32 = fat->magic == MH_MAGIC || fat->magic == MH_CIGAM;
-  BOOL swap = fat->magic == FAT_CIGAM || fat->magic == MH_CIGAM_64 ||
-    fat->magic == MH_CIGAM;
-
-  if (!is64 && !is32 && !isFat) {
-    [data release];
-    return 0;
-  }
-
-  // Load any available architectures and save the information
-  headers_ = [[NSMutableDictionary alloc] init];
-
-  if (isFat) {
-    struct fat_arch *archs =
-      (struct fat_arch *)((uint32_t)fat + sizeof(struct fat_header));
-    uint32_t count = SwapLongIfNeeded(fat->nfat_arch);
-
-    for (uint32_t i = 0; i < count; ++i) {
-      archs[i].cputype = SwapIntIfNeeded(archs[i].cputype);
-      archs[i].cpusubtype = SwapIntIfNeeded(archs[i].cpusubtype);
-      archs[i].offset = SwapLongIfNeeded(archs[i].offset);
-      archs[i].size = SwapLongIfNeeded(archs[i].size);
-      archs[i].align = SwapLongIfNeeded(archs[i].align);
+// A line-to-module loader that accepts line number info parsed by
+// dwarf2reader::LineInfo and populates a Module and a line vector
+// with the results.
+class DumpSymbols::DumperLineToModule:
+      public DwarfCUToModule::LineToModuleFunctor {
+ public:
+  // Create a line-to-module converter using BYTE_READER.
+  DumperLineToModule(dwarf2reader::ByteReader *byte_reader)
+      : byte_reader_(byte_reader) { }
+  void operator()(const char *program, uint64 length,
+                  Module *module, vector<Module::Line> *lines) {
+    DwarfLineToModule handler(module, lines);
+    dwarf2reader::LineInfo parser(program, length, byte_reader_, &handler);
+    parser.Start();
+  }
+ private:
+  dwarf2reader::ByteReader *byte_reader_;  // WEAK
+};
+
+bool DumpSymbols::ReadDwarf(google_breakpad::Module *module,
+                            const mach_o::Reader &macho_reader,
+                            const mach_o::SectionMap &dwarf_sections) const {
+  // Build a byte reader of the appropriate endianness.
+  ByteReader byte_reader(macho_reader.big_endian() 
+                         ? dwarf2reader::ENDIANNESS_BIG
+                         : dwarf2reader::ENDIANNESS_LITTLE);
+
+  // Construct a context for this file.
+  DwarfCUToModule::FileContext file_context(selected_object_name_,
+                                            module);
+
+  // Build a dwarf2reader::SectionMap from our mach_o::SectionMap.
+  for (mach_o::SectionMap::const_iterator it = dwarf_sections.begin();
+       it != dwarf_sections.end(); it++) {
+    file_context.section_map[it->first] =
+      make_pair(reinterpret_cast<const char *>(it->second.contents.start),
+                it->second.contents.Size());
+  }
+
+  // Find the __debug_info section.
+  std::pair<const char *, uint64> debug_info_section
+      = file_context.section_map["__debug_info"];
+  // There had better be a __debug_info section!
+  if (!debug_info_section.first) {
+    fprintf(stderr, "%s: __DWARF segment of file has no __debug_info section\n",
+	    selected_object_name_.c_str());
+    return false;
+  }
+ 
+  // Build a line-to-module loader for the root handler to use.
+  DumperLineToModule line_to_module(&byte_reader);
+
+  // Walk the __debug_info section, one compilation unit at a time.
+  uint64 debug_info_length = debug_info_section.second;
+  for (uint64 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, &reporter);
+    // Make a Dwarf2Handler that drives our DIEHandler.
+    dwarf2reader::DIEDispatcher die_dispatcher(&root_handler);
+    // Make a DWARF parser for the compilation unit at OFFSET.
+    dwarf2reader::CompilationUnit dwarf_reader(file_context.section_map,
+                                               offset,
+                                               &byte_reader,
+                                               &die_dispatcher);
+    // Process the entire compilation unit; get the offset of the next.
+    offset += dwarf_reader.Start();
+  }
+
+  return true;
+}
 
-      if (archs[i].cputype & CPU_ARCH_ABI64)
-        result = [self loadHeader64:bytes offset:archs[i].offset];
+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;
+    default: {
+      const NXArchInfo *arch =
+          NXGetArchInfoFromCpuType(macho_reader.cpu_type(),
+                                   macho_reader.cpu_subtype());
+      fprintf(stderr, "%s: cannot convert DWARF call frame information for ",
+              selected_object_name_.c_str());
+      if (arch)
+        fprintf(stderr, "architecture '%s'", arch->name);
       else
-        result = [self loadHeader:bytes offset:archs[i].offset];
+        fprintf(stderr, "architecture %d,%d",
+                macho_reader.cpu_type(), macho_reader.cpu_subtype());
+      fprintf(stderr, " to Breakpad symbol file: no register name table\n");
+      return false;
     }
-  } else if (is32) {
-    result = [self loadHeader:bytes offset:0];
-  } else {
-    result = [self loadHeader64:bytes offset:0];
-  }
-
-  [data release];
-  return result;
-}
-
-//=============================================================================
-static BOOL WriteFormat(int fd, const char *fmt, ...) {
-  va_list list;
-  char buffer[4096];
-  ssize_t expected, written;
-
-  va_start(list, fmt);
-  vsnprintf(buffer, sizeof(buffer), fmt, list);
-  expected = strlen(buffer);
-  written = write(fd, buffer, strlen(buffer));
-  va_end(list);
-
-  return expected == written;
-}
-
-//=============================================================================
-- (BOOL)outputSymbolFile:(int)fd {
-  // Get the baseAddress for this architecture
-  NSDictionary *archDict = [headers_ objectForKey:architecture_];
-  NSNumber *baseAddressNum = [archDict objectForKey:kHeaderBaseAddressKey];
-  uint64_t baseAddress =
-    baseAddressNum ? [baseAddressNum unsignedLongLongValue] : 0;
-  NSNumber *moduleSizeNum = [archDict objectForKey:kHeaderSizeKey];
-  uint64_t moduleSize =
-    moduleSizeNum ? [moduleSizeNum unsignedLongLongValue] : 0;
-
-  // UUID
-  FileID file_id([sourcePath_ fileSystemRepresentation]);
-  unsigned char identifier[16];
-  char identifierStr[40];
-  const char *moduleName = [[sourcePath_ lastPathComponent] UTF8String];
-  int cpu_type = [[archDict objectForKey:kHeaderCPUTypeKey] unsignedLongValue];
-  if (file_id.MachoIdentifier(cpu_type, identifier)) {
-    FileID::ConvertIdentifierToString(identifier, identifierStr,
-                                      sizeof(identifierStr));
-  }
-  else {
-    fprintf(stderr, "Unable to calculate UUID of mach-o binary!\n");
-    return NO;
   }
 
-  // keep track exclusively of function addresses
-  // for sanity checking function lengths
-  functionAddresses_ = [[NSMutableSet alloc] init];
-
-  // Gather the information
-  [self loadSymbolInfoForArchitecture];
-
-  NSArray *sortedAddresses = [[addresses_ allKeys]
-    sortedArrayUsingSelector:@selector(compare:)];
+  // Find the call frame information and its size.
+  const char *cfi = reinterpret_cast<const char *>(section.contents.start);
+  size_t cfi_size = section.contents.Size();
 
-  NSArray *sortedFunctionAddresses = [[functionAddresses_ allObjects]
-    sortedArrayUsingSelector:@selector(compare:)];
-
-  // position ourselves at the 2nd function
-  unsigned int funcIndex = 1;
-
-  // Remove the dashes from the string
-  NSMutableString *compactedStr =
-    [NSMutableString stringWithCString:identifierStr encoding:NSASCIIStringEncoding];
-  [compactedStr replaceOccurrencesOfString:@"-" withString:@"" options:0
-                                     range:NSMakeRange(0, [compactedStr length])];
-
-  if (!WriteFormat(fd, "MODULE mac %s %s0 %s\n", [architecture_ UTF8String],
-                   [compactedStr UTF8String], moduleName)) {
-    return NO;
-  }
-
-  // Sources ordered by address
-  NSArray *sources = [[sources_ allKeys]
-    sortedArrayUsingSelector:@selector(compare:)];
-  NSMutableDictionary *fileNameToFileIndex = [[NSMutableDictionary alloc] init];
-  unsigned int sourceCount = [sources count];
-  for (unsigned int i = 0; i < sourceCount; ++i) {
-    NSString *file = [sources_ objectForKey:[sources objectAtIndex:i]];
-    if (!WriteFormat(fd, "FILE %d %s\n", i + 1, [file UTF8String]))
-      return NO;
-
-    [fileNameToFileIndex setObject:[NSNumber numberWithUnsignedInt:i+1]
-                            forKey:file];
-  }
-
-  // Symbols
-  char terminatingChar = '\n';
-  uint32_t fileIdx = 0, nextFileIdx = 0;
-  uint64_t nextSourceFileAddress = 0;
-  NSNumber *nextAddress;
-  uint64_t nextAddressVal;
-  unsigned int addressCount = [sortedAddresses count];
-  
-  bool insideFunction = false;
-  
-  for (unsigned int i = 0; i < addressCount; ++i) {
-    NSNumber *address = [sortedAddresses objectAtIndex:i];
-    // skip sources that have a starting address of 0
-    if ([address unsignedLongValue] == 0) {
-      continue;
-    }
-
-    uint64_t addressVal = [address unsignedLongLongValue] - baseAddress;
-
-    // Get the next address to calculate the length
-    if (i + 1 < addressCount) {
-      nextAddress = [sortedAddresses objectAtIndex:i + 1];
-      nextAddressVal = [nextAddress unsignedLongLongValue] - baseAddress;
-    } else {
-      nextAddressVal = baseAddress + moduleSize;
-      // The symbol reader doesn't want a trailing newline
-      terminatingChar = '\0';
-    }
+  // 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);
+  dwarf2reader::ByteReader byte_reader(macho_reader.big_endian() ?
+                                       dwarf2reader::ENDIANNESS_BIG :
+                                       dwarf2reader::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);
     
-    NSDictionary *dict = [addresses_ objectForKey:address];
-    NSNumber *line = [dict objectForKey:kAddressSourceLineKey];
-    NSString *symbol = [dict objectForKey:kAddressConvertedSymbolKey];
-
-    if (!symbol)
-      symbol = [dict objectForKey:kAddressSymbolKey];
-
-    // sanity check the function length by making sure it doesn't
-    // run beyond the next function entry
-    uint64_t nextFunctionAddress = 0;
-    if (symbol && funcIndex < [sortedFunctionAddresses count]) {
-      nextFunctionAddress = [[sortedFunctionAddresses objectAtIndex:funcIndex]
-        unsignedLongLongValue] - baseAddress;
-      ++funcIndex;
-    }
-
-    // Skip some symbols
-    if ([symbol hasPrefix:@"vtable for"])
-      continue;
-
-    if ([symbol hasPrefix:@"__static_initialization_and_destruction_0"])
-      continue;
-
-    if ([symbol hasPrefix:@"_GLOBAL__I_"])
-      continue;
-
-    if ([symbol hasPrefix:@"__func__."])
-      continue;
-
-    if ([symbol hasPrefix:@"__gnu"])
-      continue;
-
-    if ([symbol hasPrefix:@"typeinfo "])
-      continue;
-
-    if ([symbol hasPrefix:@"EH_frame"])
-      continue;
-
-    if ([symbol hasPrefix:@"GCC_except_table"])
-      continue;
-
-    if ([symbol hasPrefix:@"__tcf"])
-      continue;
-
-    if ([symbol hasPrefix:@"non-virtual thunk"])
-      continue;
-
-    // Find the source file (if any) that contains this address
-    while (sourceCount && (addressVal >= nextSourceFileAddress)) {
-      fileIdx = nextFileIdx;
-
-      if (nextFileIdx < sourceCount) {
-        NSNumber *addr = [sources objectAtIndex:nextFileIdx];
-        ++nextFileIdx;
-        nextSourceFileAddress = [addr unsignedLongLongValue] - baseAddress;
-      } else {
-        nextSourceFileAddress = baseAddress + moduleSize;
-        break;
-      }
-    }
-
-    NSNumber *functionLength = [dict objectForKey:kFunctionSizeKey];
-
-    if (line) {
-      if (symbol && functionLength) {
-
-        uint64_t functionLengthVal = [functionLength unsignedLongLongValue];
-
-        insideFunction = true;
-        // sanity check to make sure the length we were told does not exceed
-        // the space between this function and the next
-        if (nextFunctionAddress != 0) {
-          uint64_t functionLengthVal2 = nextFunctionAddress - addressVal;
-
-          if(functionLengthVal > functionLengthVal2 ) {
-            functionLengthVal = functionLengthVal2;
-          }
-        }
-
-        // Function
-        if (!WriteFormat(fd, "FUNC %llx %llx 0 %s\n", addressVal,
-                         functionLengthVal, [symbol UTF8String]))
-          return NO;
-      }
-
-      // Throw out line number information that doesn't correspond to
-      // any function
-      if (insideFunction) {
-        // Source line
-        uint64_t length = nextAddressVal - addressVal;
-
-        // if fileNameToFileIndex/dict has an entry for the
-        // file/kFunctionFileKey, we're processing DWARF and have stored
-        // files for each program counter.  If there is no entry, we're
-        // processing STABS and can use the old method of mapping
-        // addresses to files(which was basically iterating over a set
-        // of addresses until we reached one that was greater than the
-        // high PC of the current file, then moving on to the next file)
-        NSNumber *fileIndex = [fileNameToFileIndex objectForKey:[dict objectForKey:kFunctionFileKey]];
-        if (!WriteFormat(fd, "%llx %llx %d %d\n", addressVal, length,
-                         [line unsignedIntValue], fileIndex ? [fileIndex unsignedIntValue] : fileIdx))
-          return NO;
-      } 
-    } else {
-      // PUBLIC <address> <stack-size> <name>
-      if (!WriteFormat(fd, "PUBLIC %llx 0 %s\n", addressVal,
-                       [symbol UTF8String]))
-        return NO;
-      insideFunction = false;
-    }
-  }
-
-  return YES;
+  dwarf2reader::CallFrameInfo::Reporter dwarf_reporter(selected_object_name_,
+                                                       section.section_name);
+  dwarf2reader::CallFrameInfo parser(cfi, cfi_size,
+                                     &byte_reader, &handler, &dwarf_reporter,
+                                     eh_frame);
+  parser.Start();
+  return true;
 }
 
-//=============================================================================
-- (id)initWithContentsOfFile:(NSString *)path {
-  if ((self = [super init])) {
-
-    if (![[NSFileManager defaultManager] fileExistsAtPath:path]) {
-      [self autorelease];
-      return nil;
-    }
-
-    sourcePath_ = [path copy];
-
-    // Test for .DSYM bundle
-    NSBundle *dsymBundle = [NSBundle bundleWithPath:sourcePath_];
-
-    if (dsymBundle) {
-
-      // we need to take the DSYM bundle path and remove it's
-      // extension to get the name of the file inside the resources
-      // directory of the bundle that actually has the DWARF
-      // information
-      // But, Xcode supports something called "Wrapper extension"(see
-      // build settings), which would make the bundle name
-      // /tmp/foo/test.kext.dSYM, but the dwarf binary name would
-      // still be "test".  so, now we loop through until deleting the
-      // extension doesn't change the string
-
-      // e.g. suppose sourcepath_ is /tmp/foo/test.dSYM
-
-      NSString *dwarfBinName = [sourcePath_ lastPathComponent];
-      NSString *dwarfBinPath;
-
-      // We use a do/while loop so we can handle files without an extension
-      do {
-        dwarfBinName = [dwarfBinName stringByDeletingPathExtension];
-        // now, dwarfBinName is "test"
-        dwarfBinPath = [dsymBundle pathForResource:dwarfBinName ofType:nil inDirectory:@"DWARF"];
-        if (dwarfBinPath != nil)
-          break;
-      } while (![[dwarfBinName stringByDeletingPathExtension] isEqualToString:dwarfBinName]);
-
-      if (dwarfBinPath == nil) {
-        NSLog(@"The bundle passed on the command line does not appear to be a DWARF dSYM bundle");
-        [self autorelease];
-        return nil;
-      }
-
-      // otherwise we're good to go
-      [sourcePath_ release];
-
-      sourcePath_ = [dwarfBinPath copy];
-      NSLog(@"Loading DWARF dSYM file from %@", sourcePath_);
-    }
-
-    sectionsForArch_ = new ArchSectionMap();
-
-    if (![self loadModuleInfo]) {
-      [self autorelease];
-      return nil;
-    }
-
-    // If there's more than one, use the native one
-    if ([headers_ count] > 1) {
-      const NXArchInfo *localArchInfo = NXGetLocalArchInfo();
-
-      if (localArchInfo) {
-        cpu_type_t cpu = localArchInfo->cputype;
-        NSString *arch;
+// 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)
+      : dumper_(dumper), module_(module), reader_(reader) { }
+
+  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_;
+};
+
+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);
+    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 (!dumper_.ReadDwarf(module_, reader_, section_map))
+      return false;
+    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;
+}
 
-        if (cpu & CPU_ARCH_ABI64)
-          arch = ((cpu & ~CPU_ARCH_ABI64) == CPU_TYPE_X86) ?
-            @"x86_64" : @"ppc64";
-        else
-          arch = (cpu == CPU_TYPE_X86) ? @"x86" : @"ppc";
+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;
+}
 
-        [self setArchitecture:arch];
+bool DumpSymbols::WriteSymbolFile(FILE *stream) {
+  // 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.
+      const NXArchInfo *local_arch = NXGetLocalArchInfo();
+      if (!SetArchitecture(local_arch->cputype, local_arch->cpusubtype)) {
+        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_ fileSystemRepresentation]);
+        return false;
       }
-    } else {
-      // Specify the default architecture
-      [self setArchitecture:[[headers_ allKeys] objectAtIndex:0]];
     }
   }
 
-  return self;
-}
-
-//=============================================================================
-- (NSArray *)availableArchitectures {
-  return [headers_ allKeys];
-}
+  assert(selected_object_file_);
 
-//=============================================================================
-- (void)dealloc {
-  [sourcePath_ release];
-  [architecture_ release];
-  [addresses_ release];
-  [functionAddresses_ release];
-  [sources_ release];
-  [headers_ release];
-  delete sectionsForArch_;
-
-  [super dealloc];
-}
+  // Find the name of the selected file's architecture, to appear in
+  // the MODULE record and in error messages.
+  const NXArchInfo *selected_arch_info
+      = NXGetArchInfoFromCpuType(selected_object_file_->cputype,
+                                 selected_object_file_->cpusubtype);
 
-//=============================================================================
-- (BOOL)setArchitecture:(NSString *)architecture {
-  NSString *normalized = [architecture lowercaseString];
-  BOOL isValid = NO;
-
-  if ([normalized isEqualToString:@"ppc"]) {
-    isValid = YES;
-  }
-  else if ([normalized isEqualToString:@"i386"]) {
-    normalized = @"x86";
-    isValid = YES;
-  }
-  else if ([normalized isEqualToString:@"x86"]) {
-    isValid = YES;
-  }
-  else if ([normalized isEqualToString:@"ppc64"]) {
-    isValid = YES;
-  }
-  else if ([normalized isEqualToString:@"x86_64"]) {
-    isValid = YES;
+  // 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_ UTF8String];
+  if (object_files_.size() > 1) {
+    selected_object_name_ += ", architecture ";
+    selected_object_name_ + selected_arch_info->name;
   }
 
-  if (isValid) {
-    if (![headers_ objectForKey:normalized])
-      return NO;
+  // Compute a module name, to appear in the MODULE record.
+  NSString *module_name = [object_filename_ lastPathComponent];
 
-    [architecture_ autorelease];
-    architecture_ = [normalized copy];
-  }
+  // Choose an identifier string, to appear in the MODULE record.
+  string identifier = Identifier();
+  if (identifier.empty())
+    return false;
+  identifier += "0";
 
-  return isValid;
-}
-
-//=============================================================================
-- (NSString *)architecture {
-  return architecture_;
-}
+  // Create a module to hold the debugging information.
+  Module module([module_name UTF8String], "mac", selected_arch_info->name, 
+                identifier);
 
-//=============================================================================
-- (BOOL)writeSymbolFile:(NSString *)destinationPath {
-  const char *dest = [destinationPath fileSystemRepresentation];
-  int fd;
+  // Parse the selected object file.
+  mach_o::Reader::Reporter reporter(selected_object_name_);
+  mach_o::Reader reader(&reporter);
+  if (!reader.Read(reinterpret_cast<const uint8_t *>([contents_ bytes])
+                   + selected_object_file_->offset,
+                   selected_object_file_->size,
+		   selected_object_file_->cputype,
+		   selected_object_file_->cpusubtype))
+    return false;
 
-  if ([[destinationPath substringToIndex:1] isEqualToString:@"-"])
-    fd = STDOUT_FILENO;
-  else
-    fd = open(dest, O_WRONLY | O_CREAT | O_TRUNC, 0666);
+  // Walk its load commands, and deal with whatever is there.
+  LoadCommandDumper load_command_dumper(*this, &module, reader);
+  if (!reader.WalkLoadCommands(&load_command_dumper))
+    return false;
 
-  if (fd == -1)
-    return NO;
-
-  BOOL result = [self outputSymbolFile:fd];
-
-  close(fd);
-
-  return result;
+  return module.Write(stream);
 }
 
-@end
-
-@implementation MachSection 
-
-- (id)initWithMachSection:(section *)sect andNumber:(uint32_t)sectionNumber {
-  if ((self = [super init])) {
-    sect_ = sect;
-    sectionNumber_ = sectionNumber;
-  }
-
-  return self;
-}
-
-- (section*)sectionPointer {
-  return sect_;
-}
-
-- (uint32_t)sectionNumber {
-  return sectionNumber_;
-}
-@end
+}  // namespace google_breakpad
diff --git a/src/common/mac/macho_walker.cc b/src/common/mac/macho_walker.cc
index 4e1d9f16..ecea8997 100644
--- a/src/common/mac/macho_walker.cc
+++ b/src/common/mac/macho_walker.cc
@@ -62,22 +62,11 @@ MachoWalker::~MachoWalker() {
 }
 
 int MachoWalker::ValidateCPUType(int cpu_type) {
-  // If the user didn't specify, try to use the local architecture.  If that
-  // fails, use the base type for the executable.
+  // If the user didn't specify, use the local architecture.
   if (cpu_type == 0) {
     const NXArchInfo *arch = NXGetLocalArchInfo();
-    if (arch)
-      cpu_type = arch->cputype;
-    else
-#if __ppc__
-      cpu_type = CPU_TYPE_POWERPC;
-#elif __i386__
-      cpu_type = CPU_TYPE_X86;
-#elif __x86_64__
-      cpu_type = CPU_TYPE_X86_64;
-#else
-#error Unknown architecture -- are you on a PDP-11?
-#endif
+    assert(arch);
+    cpu_type = arch->cputype;
   }
 
   return cpu_type;
diff --git a/src/tools/mac/dump_syms/dump_syms.xcodeproj/project.pbxproj b/src/tools/mac/dump_syms/dump_syms.xcodeproj/project.pbxproj
index 0c345928..f492bd7a 100644
--- a/src/tools/mac/dump_syms/dump_syms.xcodeproj/project.pbxproj
+++ b/src/tools/mac/dump_syms/dump_syms.xcodeproj/project.pbxproj
@@ -8,6 +8,15 @@
 
 /* Begin PBXBuildFile section */
 		B88FAE0B11665B5700407530 /* test_assembler.cc in Sources */ = {isa = PBXBuildFile; fileRef = B88FAE0911665B5700407530 /* test_assembler.cc */; };
+		B88FAE1911665FE400407530 /* dwarf2diehandler.cc in Sources */ = {isa = PBXBuildFile; fileRef = B88FAE1711665FE400407530 /* dwarf2diehandler.cc */; };
+		B88FAE261166603300407530 /* dwarf_cu_to_module.cc in Sources */ = {isa = PBXBuildFile; fileRef = B88FAE1E1166603300407530 /* dwarf_cu_to_module.cc */; };
+		B88FAE271166603300407530 /* dwarf_line_to_module.cc in Sources */ = {isa = PBXBuildFile; fileRef = B88FAE201166603300407530 /* dwarf_line_to_module.cc */; };
+		B88FAE281166603300407530 /* language.cc in Sources */ = {isa = PBXBuildFile; fileRef = B88FAE221166603300407530 /* language.cc */; };
+		B88FAE291166603300407530 /* module.cc in Sources */ = {isa = PBXBuildFile; fileRef = B88FAE241166603300407530 /* module.cc */; };
+		B88FAE2C1166606200407530 /* macho_reader.cc in Sources */ = {isa = PBXBuildFile; fileRef = B89E0E6E1166571D00DD08C9 /* macho_reader.cc */; };
+		B88FAE351166673E00407530 /* dwarf_cfi_to_module.cc in Sources */ = {isa = PBXBuildFile; fileRef = B88FAE331166673E00407530 /* dwarf_cfi_to_module.cc */; };
+		B88FAE3B11666C6F00407530 /* stabs_reader.cc in Sources */ = {isa = PBXBuildFile; fileRef = B88FAE3911666C6F00407530 /* stabs_reader.cc */; settings = {COMPILER_FLAGS = "-DHAVE_MACH_O_NLIST_H"; }; };
+		B88FAE3E11666C8900407530 /* stabs_to_module.cc in Sources */ = {isa = PBXBuildFile; fileRef = B88FAE3C11666C8900407530 /* stabs_to_module.cc */; };
 		B89E0E601166556C00DD08C9 /* libcrypto.dylib in Frameworks */ = {isa = PBXBuildFile; fileRef = B89E0E5F1166556C00DD08C9 /* libcrypto.dylib */; };
 		B89E0E781166576C00DD08C9 /* macho_reader.cc in Sources */ = {isa = PBXBuildFile; fileRef = B89E0E6E1166571D00DD08C9 /* macho_reader.cc */; };
 		B89E0E7A1166576C00DD08C9 /* macho_dump.cc in Sources */ = {isa = PBXBuildFile; fileRef = B89E0E701166573700DD08C9 /* macho_dump.cc */; };
@@ -16,7 +25,6 @@
 		B89E0EA111665AC300DD08C9 /* gtest_main.cc in Sources */ = {isa = PBXBuildFile; fileRef = B89E0E9F11665AC300DD08C9 /* gtest_main.cc */; };
 		B89E0EA211665AC300DD08C9 /* gtest-all.cc in Sources */ = {isa = PBXBuildFile; fileRef = B89E0EA011665AC300DD08C9 /* gtest-all.cc */; };
 		B89E0EA411665AEA00DD08C9 /* gmock-all.cc in Sources */ = {isa = PBXBuildFile; fileRef = B89E0EA311665AEA00DD08C9 /* gmock-all.cc */; };
-		B8C5B5161166534700D34F4E /* functioninfo.cc in Sources */ = {isa = PBXBuildFile; fileRef = F9C7ED420E8AD93000E953AD /* functioninfo.cc */; };
 		B8C5B5171166534700D34F4E /* dwarf2reader.cc in Sources */ = {isa = PBXBuildFile; fileRef = F95B422F0E0E22D100DBDE83 /* dwarf2reader.cc */; };
 		B8C5B5181166534700D34F4E /* bytereader.cc in Sources */ = {isa = PBXBuildFile; fileRef = F95B422C0E0E22D100DBDE83 /* bytereader.cc */; };
 		B8C5B5191166534700D34F4E /* macho_utilities.cc in Sources */ = {isa = PBXBuildFile; fileRef = 557800890BE1F3AB00EC23E0 /* macho_utilities.cc */; };
@@ -43,6 +51,23 @@
 		9BE650460B52F6D800611104 /* macho_walker.h */ = {isa = PBXFileReference; fileEncoding = 30; lastKnownFileType = sourcecode.c.h; name = macho_walker.h; path = ../../../common/mac/macho_walker.h; sourceTree = SOURCE_ROOT; };
 		B88FAE0911665B5700407530 /* test_assembler.cc */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; name = test_assembler.cc; path = ../../../common/test_assembler.cc; sourceTree = SOURCE_ROOT; };
 		B88FAE0A11665B5700407530 /* test_assembler.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = test_assembler.h; path = ../../../common/test_assembler.h; sourceTree = SOURCE_ROOT; };
+		B88FAE1711665FE400407530 /* dwarf2diehandler.cc */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; name = dwarf2diehandler.cc; path = ../../../common/dwarf/dwarf2diehandler.cc; sourceTree = SOURCE_ROOT; };
+		B88FAE1811665FE400407530 /* dwarf2diehandler.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = dwarf2diehandler.h; path = ../../../common/dwarf/dwarf2diehandler.h; sourceTree = SOURCE_ROOT; };
+		B88FAE1D1166603300407530 /* byte_cursor.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = byte_cursor.h; path = ../../../common/byte_cursor.h; sourceTree = SOURCE_ROOT; };
+		B88FAE1E1166603300407530 /* dwarf_cu_to_module.cc */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; name = dwarf_cu_to_module.cc; path = ../../../common/dwarf_cu_to_module.cc; sourceTree = SOURCE_ROOT; };
+		B88FAE1F1166603300407530 /* dwarf_cu_to_module.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = dwarf_cu_to_module.h; path = ../../../common/dwarf_cu_to_module.h; sourceTree = SOURCE_ROOT; };
+		B88FAE201166603300407530 /* dwarf_line_to_module.cc */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; name = dwarf_line_to_module.cc; path = ../../../common/dwarf_line_to_module.cc; sourceTree = SOURCE_ROOT; };
+		B88FAE211166603300407530 /* dwarf_line_to_module.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = dwarf_line_to_module.h; path = ../../../common/dwarf_line_to_module.h; sourceTree = SOURCE_ROOT; };
+		B88FAE221166603300407530 /* language.cc */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; name = language.cc; path = ../../../common/language.cc; sourceTree = SOURCE_ROOT; };
+		B88FAE231166603300407530 /* language.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = language.h; path = ../../../common/language.h; sourceTree = SOURCE_ROOT; };
+		B88FAE241166603300407530 /* module.cc */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; name = module.cc; path = ../../../common/module.cc; sourceTree = SOURCE_ROOT; };
+		B88FAE251166603300407530 /* module.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = module.h; path = ../../../common/module.h; sourceTree = SOURCE_ROOT; };
+		B88FAE331166673E00407530 /* dwarf_cfi_to_module.cc */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; name = dwarf_cfi_to_module.cc; path = ../../../common/dwarf_cfi_to_module.cc; sourceTree = SOURCE_ROOT; };
+		B88FAE341166673E00407530 /* dwarf_cfi_to_module.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = dwarf_cfi_to_module.h; path = ../../../common/dwarf_cfi_to_module.h; sourceTree = SOURCE_ROOT; };
+		B88FAE3911666C6F00407530 /* stabs_reader.cc */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; name = stabs_reader.cc; path = ../../../common/stabs_reader.cc; sourceTree = SOURCE_ROOT; };
+		B88FAE3A11666C6F00407530 /* stabs_reader.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = stabs_reader.h; path = ../../../common/stabs_reader.h; sourceTree = SOURCE_ROOT; };
+		B88FAE3C11666C8900407530 /* stabs_to_module.cc */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; name = stabs_to_module.cc; path = ../../../common/stabs_to_module.cc; sourceTree = SOURCE_ROOT; };
+		B88FAE3D11666C8900407530 /* stabs_to_module.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = stabs_to_module.h; path = ../../../common/stabs_to_module.h; sourceTree = SOURCE_ROOT; };
 		B89E0E5F1166556C00DD08C9 /* libcrypto.dylib */ = {isa = PBXFileReference; lastKnownFileType = "compiled.mach-o.dylib"; name = libcrypto.dylib; path = /usr/lib/libcrypto.dylib; sourceTree = "<absolute>"; };
 		B89E0E6D1166571D00DD08C9 /* macho_reader_unittest.cc */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; name = macho_reader_unittest.cc; path = ../../../common/mac/macho_reader_unittest.cc; sourceTree = SOURCE_ROOT; };
 		B89E0E6E1166571D00DD08C9 /* macho_reader.cc */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; name = macho_reader.cc; path = ../../../common/mac/macho_reader.cc; sourceTree = SOURCE_ROOT; };
@@ -62,8 +87,6 @@
 		F95B422F0E0E22D100DBDE83 /* dwarf2reader.cc */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; name = dwarf2reader.cc; path = ../../../common/dwarf/dwarf2reader.cc; sourceTree = SOURCE_ROOT; };
 		F95B42300E0E22D100DBDE83 /* dwarf2reader.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = dwarf2reader.h; path = ../../../common/dwarf/dwarf2reader.h; sourceTree = SOURCE_ROOT; };
 		F95B42310E0E22D100DBDE83 /* line_state_machine.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = line_state_machine.h; path = ../../../common/dwarf/line_state_machine.h; sourceTree = SOURCE_ROOT; };
-		F9C7ED420E8AD93000E953AD /* functioninfo.cc */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; name = functioninfo.cc; path = ../../../common/dwarf/functioninfo.cc; sourceTree = SOURCE_ROOT; };
-		F9F5344D0E7C902C0012363F /* functioninfo.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = functioninfo.h; path = ../../../common/dwarf/functioninfo.h; sourceTree = SOURCE_ROOT; };
 /* End PBXFileReference section */
 
 /* Begin PBXFrameworksBuildPhase section */
@@ -99,6 +122,8 @@
 				B89E0E9D11665A9500DD08C9 /* TESTING */,
 				F9F5344B0E7C8FFC0012363F /* DWARF */,
 				B89E0E6C1166569700DD08C9 /* MACHO */,
+				B88FAE3811666A1700407530 /* STABS */,
+				B88FAE1C11665FFD00407530 /* MODULE */,
 				B8E8CA0C1156C854009E61B2 /* byteswap.h */,
 				9BE650410B52F6D800611104 /* file_id.cc */,
 				9BE650420B52F6D800611104 /* file_id.h */,
@@ -131,6 +156,35 @@
 			name = Products;
 			sourceTree = "<group>";
 		};
+		B88FAE1C11665FFD00407530 /* MODULE */ = {
+			isa = PBXGroup;
+			children = (
+				B88FAE1D1166603300407530 /* byte_cursor.h */,
+				B88FAE1E1166603300407530 /* dwarf_cu_to_module.cc */,
+				B88FAE1F1166603300407530 /* dwarf_cu_to_module.h */,
+				B88FAE201166603300407530 /* dwarf_line_to_module.cc */,
+				B88FAE211166603300407530 /* dwarf_line_to_module.h */,
+				B88FAE221166603300407530 /* language.cc */,
+				B88FAE231166603300407530 /* language.h */,
+				B88FAE241166603300407530 /* module.cc */,
+				B88FAE251166603300407530 /* module.h */,
+				B88FAE331166673E00407530 /* dwarf_cfi_to_module.cc */,
+				B88FAE341166673E00407530 /* dwarf_cfi_to_module.h */,
+				B88FAE3C11666C8900407530 /* stabs_to_module.cc */,
+				B88FAE3D11666C8900407530 /* stabs_to_module.h */,
+			);
+			name = MODULE;
+			sourceTree = "<group>";
+		};
+		B88FAE3811666A1700407530 /* STABS */ = {
+			isa = PBXGroup;
+			children = (
+				B88FAE3911666C6F00407530 /* stabs_reader.cc */,
+				B88FAE3A11666C6F00407530 /* stabs_reader.h */,
+			);
+			name = STABS;
+			sourceTree = "<group>";
+		};
 		B89E0E6C1166569700DD08C9 /* MACHO */ = {
 			isa = PBXGroup;
 			children = (
@@ -162,8 +216,6 @@
 		F9F5344B0E7C8FFC0012363F /* DWARF */ = {
 			isa = PBXGroup;
 			children = (
-				F9C7ED420E8AD93000E953AD /* functioninfo.cc */,
-				F9F5344D0E7C902C0012363F /* functioninfo.h */,
 				F95B422E0E0E22D100DBDE83 /* dwarf2enums.h */,
 				F95B422F0E0E22D100DBDE83 /* dwarf2reader.cc */,
 				F95B42300E0E22D100DBDE83 /* dwarf2reader.h */,
@@ -171,6 +223,8 @@
 				F95B422B0E0E22D100DBDE83 /* bytereader-inl.h */,
 				F95B422C0E0E22D100DBDE83 /* bytereader.cc */,
 				F95B42310E0E22D100DBDE83 /* line_state_machine.h */,
+				B88FAE1711665FE400407530 /* dwarf2diehandler.cc */,
+				B88FAE1811665FE400407530 /* dwarf2diehandler.h */,
 			);
 			name = DWARF;
 			sourceTree = "<group>";
@@ -231,9 +285,6 @@
 /* Begin PBXProject section */
 		08FB7793FE84155DC02AAC07 /* Project object */ = {
 			isa = PBXProject;
-			attributes = {
-				BuildIndependentTargetsInParallel = NO;
-			};
 			buildConfigurationList = 1DEB927808733DD40010E9CD /* Build configuration list for PBXProject "dump_syms" */;
 			compatibilityVersion = "Xcode 2.4";
 			hasScannedForEncodings = 1;
@@ -275,7 +326,7 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
-				B8C5B5161166534700D34F4E /* functioninfo.cc in Sources */,
+				B88FAE2C1166606200407530 /* macho_reader.cc in Sources */,
 				B8C5B5171166534700D34F4E /* dwarf2reader.cc in Sources */,
 				B8C5B5181166534700D34F4E /* bytereader.cc in Sources */,
 				B8C5B5191166534700D34F4E /* macho_utilities.cc in Sources */,
@@ -284,6 +335,14 @@
 				B8C5B51C1166534700D34F4E /* macho_walker.cc in Sources */,
 				B8C5B51D1166534700D34F4E /* dump_syms.mm in Sources */,
 				B8C5B51E1166534700D34F4E /* dump_syms_tool.mm in Sources */,
+				B88FAE1911665FE400407530 /* dwarf2diehandler.cc in Sources */,
+				B88FAE261166603300407530 /* dwarf_cu_to_module.cc in Sources */,
+				B88FAE271166603300407530 /* dwarf_line_to_module.cc in Sources */,
+				B88FAE281166603300407530 /* language.cc in Sources */,
+				B88FAE291166603300407530 /* module.cc in Sources */,
+				B88FAE351166673E00407530 /* dwarf_cfi_to_module.cc in Sources */,
+				B88FAE3B11666C6F00407530 /* stabs_reader.cc in Sources */,
+				B88FAE3E11666C8900407530 /* stabs_to_module.cc in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
diff --git a/src/tools/mac/dump_syms/dump_syms_tool.mm b/src/tools/mac/dump_syms/dump_syms_tool.mm
index bd741220..0b8c11b9 100644
--- a/src/tools/mac/dump_syms/dump_syms_tool.mm
+++ b/src/tools/mac/dump_syms/dump_syms_tool.mm
@@ -35,9 +35,14 @@
 #include <mach-o/arch.h>
 #include <unistd.h>
 
+#include <vector>
+
 #include "common/mac/dump_syms.h"
 #include "common/mac/macho_utilities.h"
 
+using google_breakpad::DumpSymbols;
+using std::vector;
+
 struct Options {
   Options() : srcPath(), arch() { }
   NSString *srcPath;
@@ -46,24 +51,38 @@ struct Options {
 
 //=============================================================================
 static bool Start(const Options &options) {
-  DumpSymbols *dump = [[DumpSymbols alloc]
-                        initWithContentsOfFile:options.srcPath];
-  
-  if (!dump) {
-    fprintf(stderr, "%s is not a valid Mach-o file\n",
-            [options.srcPath fileSystemRepresentation]);
-    return false;
-  }
+  DumpSymbols dump_symbols;
 
-  if (![dump setArchitecture:[NSString
-                              stringWithUTF8String:options.arch->name]]) {
-    fprintf(stderr, "Architecture: %s not available in %s\n", 
-            options.arch->name,
-            [options.srcPath fileSystemRepresentation]);
+  if (!dump_symbols.Read(options.srcPath))
     return false;
+
+  if (options.arch) {
+    if (!dump_symbols.SetArchitecture(options.arch->cputype,
+                                      options.arch->cpusubtype)) {
+      fprintf(stderr, "%s: no architecture '%s' is present in file.\n",
+              [options.srcPath fileSystemRepresentation], options.arch->name);
+      size_t available_size;
+      const struct fat_arch *available =
+        dump_symbols.AvailableArchitectures(&available_size);
+      if (available_size == 1)
+        fprintf(stderr, "the file's architecture is: ");
+      else
+        fprintf(stderr, "architectures present in the file are:\n");
+      for (size_t i = 0; i < available_size; i++) {
+        const struct fat_arch *arch = &available[i];
+        const NXArchInfo *arch_info =
+          NXGetArchInfoFromCpuType(arch->cputype, arch->cpusubtype);
+        if (arch_info)
+          fprintf(stderr, "%s (%s)\n", arch_info->name, arch_info->description);
+        else
+          fprintf(stderr, "unrecognized cpu type 0x%x, subtype 0x%x\n",
+                  arch->cputype, arch->cpusubtype);
+      }
+      return false;
+    }
   }
-  
-  return [dump writeSymbolFile:@"-"];
+      
+  return dump_symbols.WriteSymbolFile(stdout);
 }
 
 //=============================================================================
@@ -71,7 +90,8 @@ static void Usage(int argc, const char *argv[]) {
   fprintf(stderr, "Output a Breakpad symbol file from a Mach-o file.\n");
   fprintf(stderr, "Usage: %s [-a ARCHITECTURE] <Mach-o file>\n",
           argv[0]);
-  fprintf(stderr, "\t-a: Architecture type [default: native]\n");
+  fprintf(stderr, "\t-a: Architecture type [default: native, or whatever is\n");
+  fprintf(stderr, "\t    in the file, if it contains only one architecture]\n");
   fprintf(stderr, "\t-h: Usage\n");
   fprintf(stderr, "\t-?: Usage\n");
 }
@@ -81,8 +101,6 @@ static void SetupOptions(int argc, const char *argv[], Options *options) {
   extern int optind;
   signed char ch;
 
-  options->arch = NXGetLocalArchInfo();
-
   while ((ch = getopt(argc, (char * const *)argv, "a:h?")) != -1) {
     switch (ch) {
       case 'a': {