supersize: Track symbol aliases and shared symbols

tools/binary_size/libsupersize/archive.py

 # Copyright 2017 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Main Python API for analyzing binary size."""
 
 import argparse
 import calendar
 import collections
 import datetime
 import gzip
 import logging
 import os
 import posixpath
 import re
 import subprocess
 import sys
 import tempfile
 import zipfile
 
+import concurrent
 import describe
 import file_format
 import function_signature
-import helpers
 import linker_map_parser
 import models
 import ninja_parser
+import nm
 import paths
 
 
 def _OpenMaybeGz(path, mode=None):
   """Calls `gzip.open()` if |path| ends in ".gz", otherwise calls `open()`."""
   if path.endswith('.gz'):
     if mode and 'w' in mode:
       return gzip.GzipFile(path, mode, 1)
     return gzip.open(path, mode)
   return open(path, mode or 'r')
@@ skipping 82 matching lines @@
       symbol.full_name = symbol.name
       symbol.name = re.sub(r'\(.*\)', '', symbol.full_name)
 
     # Don't bother storing both if they are the same.
     if symbol.full_name == symbol.name:
       symbol.full_name = ''
 
   logging.debug('Found name prefixes of: %r', found_prefixes)
 
 
-def _NormalizeObjectPaths(symbols):
-  """Ensures that all paths are formatted in a useful way."""
-  for symbol in symbols:
-    path = symbol.object_path
-    if path.startswith('obj/'):
-      # Convert obj/third_party/... -> third_party/...
-      path = path[4:]
-    elif path.startswith('../../'):
-      # Convert ../../third_party/... -> third_party/...
-      path = path[6:]
-    if path.endswith(')'):
-      # Convert foo/bar.a(baz.o) -> foo/bar.a/baz.o
-      start_idx = path.index('(')
-      path = os.path.join(path[:start_idx], path[start_idx + 1:-1])
-    symbol.object_path = path
+def _NormalizeObjectPath(path):
+  if path.startswith('obj/'):
+    # Convert obj/third_party/... -> third_party/...
+    path = path[4:]
+  elif path.startswith('../../'):
+    # Convert ../../third_party/... -> third_party/...
+    path = path[6:]
+  if path.endswith(')'):
+    # Convert foo/bar.a(baz.o) -> foo/bar.a/baz.o
+    start_idx = path.index('(')
+    path = os.path.join(path[:start_idx], path[start_idx + 1:-1])
+  return path
 
 
 def _NormalizeSourcePath(path):
   if path.startswith('gen/'):
     # Convert gen/third_party/... -> third_party/...
     return path[4:]
   if path.startswith('../../'):
     # Convert ../../third_party/... -> third_party/...
     return path[6:]
   return path
 
 
+def _SourcePathForObjectPath(object_path, source_mapper):
+  # We don't have source info for prebuilt .a files.
+  if not os.path.isabs(object_path) and not object_path.startswith('..'):
+    source_path = source_mapper.FindSourceForPath(object_path)
+    if source_path:
+      return _NormalizeSourcePath(source_path)
+  return ''
+
+
 def _ExtractSourcePaths(symbols, source_mapper):
-  """Fills in the .source_path attribute of all symbols."""
+  """Fills in the |source_path| attribute."""
   logging.debug('Parsed %d .ninja files.', source_mapper.parsed_file_count)
-
   for symbol in symbols:
     object_path = symbol.object_path
-    if symbol.source_path or not object_path:
+    if object_path and not symbol.source_path:
+      symbol.source_path = _SourcePathForObjectPath(object_path, source_mapper)
+
+
+def _ComputeAnscestorPath(path_list):
+  """Returns the common anscestor of the given paths."""
+  # Ignore missing paths.
+  path_list = [p for p in path_list if p]
+  prefix = os.path.commonprefix(path_list)
+  # Put the path count as a subdirectory to allow for better grouping when
+  # path-based breakdowns.
+  if not prefix:
+    if len(path_list) < 2:
+      return ''
+    return os.path.join('{shared}', str(len(path_list)))
+  if prefix == path_list[0]:
+    return prefix
+  assert len(path_list) > 1, 'path_list: ' + repr(path_list)
+  return os.path.join(os.path.dirname(prefix), '{shared}', str(len(path_list)))
+
+
+# This must normalize object paths at the same time because normalization
+# needs to occur before finding common ancestor.
+def _ComputeAnscestorPathsAndNormalizeObjectPaths(
+    symbols, object_paths_by_name, source_mapper):
+  num_found_paths = 0
+  num_unknown_names = 0
+  num_path_mismatches = 0
+  num_unmatched_aliases = 0
+  for symbol in symbols:
+    name = symbol.name
+    if (symbol.IsBss() or
+        not name or
+        name[0] in '*.' or  # e.g. ** merge symbols, .Lswitch.table
+        name == 'startup'):
+      symbol.object_path = _NormalizeObjectPath(symbol.object_path)
       continue
-    # We don't have source info for prebuilt .a files.
-    if not os.path.isabs(object_path) and not object_path.startswith('..'):
-      source_path = source_mapper.FindSourceForPath(object_path)
-      if source_path:
-        symbol.source_path = _NormalizeSourcePath(source_path)
+
+    object_paths = object_paths_by_name.get(name)
+    if object_paths:
+      num_found_paths += 1
+    else:
+      if not symbol.object_path and symbol.aliases:
+        # Happens when aliases are from object files where all symbols were
+        # pruned or de-duped as aliases. Since we are only scanning .o files
+        # referenced by included symbols, such files are missed.
+        # TODO(agrieve): This could be fixed by retrieving linker inputs from
+        #     build.ninja, or by looking for paths within the .map file's
+        #     discarded sections.
+        num_unmatched_aliases += 1
+        continue
+      if num_unknown_names < 10:
+        logging.warning('Symbol not found in any .o files: %r', symbol)
+      num_unknown_names += 1
+      symbol.object_path = _NormalizeObjectPath(symbol.object_path)
+      continue
+
+    if symbol.object_path and symbol.object_path not in object_paths:
+      if num_path_mismatches < 10:
+        logging.warning('Symbol path reported by .map not found by nm.')
+        logging.warning('sym=%r', symbol)
+        logging.warning('paths=%r', object_paths)
+      num_path_mismatches += 1
+
+    if source_mapper:
+      source_paths = [
+          _SourcePathForObjectPath(p, source_mapper) for p in object_paths]
+      symbol.source_path = _ComputeAnscestorPath(source_paths)
+
+    object_paths = [_NormalizeObjectPath(p) for p in object_paths]
+    symbol.object_path = _ComputeAnscestorPath(object_paths)
+
+  logging.debug('Cross-referenced %d symbols with nm output. '
+                'num_unknown_names=%d num_path_mismatches=%d '
+                'num_unused_aliases=%d', num_found_paths, num_unknown_names,
+                num_path_mismatches, num_unmatched_aliases)
+
+
+def _DiscoverMissedObjectPaths(symbols, elf_object_paths):
+  # Missing object paths are caused by .a files added by -l flags, which are not
+  # listed as explicit inputs within .ninja rules.
+  parsed_inputs = set(elf_object_paths)
+  missed_inputs = set()
+  for symbol in symbols:
+    path = symbol.object_path
+    if path.endswith(')'):
+      # Convert foo/bar.a(baz.o) -> foo/bar.a
+      path = path[:path.index('(')]
+    if path and path not in parsed_inputs:
+      missed_inputs.add(path)
+  return missed_inputs
 
 
 def _CalculatePadding(symbols):
   """Populates the |padding| field based on symbol addresses.
 
   Symbols must already be sorted by |address|.
   """
   seen_sections = []
   for i, symbol in enumerate(symbols[1:]):
     prev_symbol = symbols[i]
     if prev_symbol.section_name != symbol.section_name:
       assert symbol.section_name not in seen_sections, (
           'Input symbols must be sorted by section, then address.')
       seen_sections.append(symbol.section_name)
       continue
     if symbol.address <= 0 or prev_symbol.address <= 0:
       continue
-    # Padding-only symbols happen for ** symbol gaps.
-    prev_is_padding_only = prev_symbol.size_without_padding == 0
-    if symbol.address == prev_symbol.address and not prev_is_padding_only:
-      assert False, 'Found duplicate symbols:\n%r\n%r' % (prev_symbol, symbol)
-    # Even with symbols at the same address removed, overlaps can still
-    # happen. In this case, padding will be negative (and this is fine).
+
+    if symbol.address == prev_symbol.address:
+      if symbol.aliases and symbol.aliases is prev_symbol.aliases:
+        symbol.padding = prev_symbol.padding
+        symbol.size = prev_symbol.size
+        continue
+      # Padding-only symbols happen for ** symbol gaps.
+      assert prev_symbol.size_without_padding == 0, (
+          'Found duplicate symbols:\n%r\n%r' % (prev_symbol, symbol))
+
     padding = symbol.address - prev_symbol.end_address
-    # These thresholds were found by manually auditing arm32 Chrome.
-    # E.g.: Set them to 0 and see what warnings get logged.
+    # These thresholds were found by experimenting with arm32 Chrome.
+    # E.g.: Set them to 0 and see what warnings get logged, then take max value.
     # TODO(agrieve): See if these thresholds make sense for architectures
     #     other than arm32.
     if not symbol.name.startswith('*') and (
         symbol.section in 'rd' and padding >= 256 or
         symbol.section in 't' and padding >= 64):
-      # For nm data, this is caused by data that has no associated symbol.
-      # The linker map file lists them with no name, but with a file.
-      # Example:
-      #   .data 0x02d42764 0x120 .../V8SharedWorkerGlobalScope.o
-      # Where as most look like:
-      #   .data.MANGLED_NAME...
-      logging.debug('Large padding of %d between:\n  A) %r\n  B) %r' % (
-                    padding, prev_symbol, symbol))
-      continue
+      # Should not happen.
+      logging.warning('Large padding of %d between:\n  A) %r\n  B) %r' % (
+                      padding, prev_symbol, symbol))
     symbol.padding = padding
     symbol.size += padding
     assert symbol.size >= 0, (
         'Symbol has negative size (likely not sorted propertly): '
         '%r\nprev symbol: %r' % (symbol, prev_symbol))
 
 
 def _ClusterSymbols(symbols):
   """Returns a new list of symbols with some symbols moved into groups.
 
@@ skipping 90 matching lines @@
           group_symbols, name=name_tup[0], full_name=name_tup[1],
           section_name=group_symbols[0].section_name)
       dest_index += 1
 
   assert len(grouped_symbols[dest_index:None]) == len(symbols[src_index:None])
   grouped_symbols[dest_index:None] = symbols[src_index:None]
   logging.debug('Finished making groups.')
   return grouped_symbols
 
 
+def _AddSymbolAliases(symbols, aliases_by_address):
+  # Step 1: Create list of (index_of_symbol, name_list).
+  logging.debug('Creating alias list')
+  replacements = []
+  num_new_symbols = 0
+  for i, s in enumerate(symbols):
+    # Don't alias padding-only symbols (e.g. ** symbol gap)
+    if s.size_without_padding == 0:
+      continue
+    name_list = aliases_by_address.get(s.address)
+    if name_list:
+      if s.name not in name_list:
+        logging.warning('Name missing from aliases: %s %s', s.name, name_list)
+        continue
+      replacements.append((i, name_list))
+      num_new_symbols += len(name_list) - 1
+
+  # Step 2: Create new symbols as siblings to each existing one.
+  logging.debug('Creating %d aliases', num_new_symbols)
+  src_cursor_end = len(symbols)
+  symbols += [None] * num_new_symbols
+  dst_cursor_end = len(symbols)
+  for src_index, name_list in reversed(replacements):
+    # Copy over symbols that come after the current one.
+    chunk_size = src_cursor_end - src_index - 1
+    dst_cursor_end -= chunk_size
+    src_cursor_end -= chunk_size
+    symbols[dst_cursor_end:dst_cursor_end + chunk_size] = (
+        symbols[src_cursor_end:src_cursor_end + chunk_size])
+    sym = symbols[src_index]
+    src_cursor_end -= 1
+
+    # Create aliases (does not bother reusing the existing symbol).
+    aliases = [None] * len(name_list)
+    for i, name in enumerate(name_list):
+      aliases[i] = models.Symbol(
+          sym.section_name, sym.size, address=sym.address, name=name,
+          aliases=aliases)
+
+    dst_cursor_end -= len(aliases)
+    symbols[dst_cursor_end:dst_cursor_end + len(aliases)] = aliases
+
+  assert dst_cursor_end == src_cursor_end
+
+
 def LoadAndPostProcessSizeInfo(path):
   """Returns a SizeInfo for the given |path|."""
   logging.debug('Loading results from: %s', path)
   size_info = file_format.LoadSizeInfo(path)
   _PostProcessSizeInfo(size_info)
   return size_info
 
 
 def _PostProcessSizeInfo(size_info):
   logging.info('Normalizing symbol names')
   _NormalizeNames(size_info.raw_symbols)
   logging.info('Calculating padding')
   _CalculatePadding(size_info.raw_symbols)
   logging.info('Grouping decomposed functions')
   size_info.symbols = models.SymbolGroup(
       _ClusterSymbols(size_info.raw_symbols))
   logging.info('Processed %d symbols', len(size_info.raw_symbols))
 
 
-def CreateSizeInfo(map_path, lazy_paths=None, no_source_paths=False,
+def CreateMetadata(map_path, elf_path, apk_path, tool_prefix, output_directory):
+  metadata = None
+  if elf_path:
+    logging.debug('Constructing metadata')
+    git_rev = _DetectGitRevision(os.path.dirname(elf_path))
+    architecture = _ArchFromElf(elf_path, tool_prefix)
+    build_id = BuildIdFromElf(elf_path, tool_prefix)
+    timestamp_obj = datetime.datetime.utcfromtimestamp(os.path.getmtime(
+        elf_path))
+    timestamp = calendar.timegm(timestamp_obj.timetuple())
+
+    metadata = {
+        models.METADATA_GIT_REVISION: git_rev,
+        models.METADATA_ELF_ARCHITECTURE: architecture,
+        models.METADATA_ELF_MTIME: timestamp,
+        models.METADATA_ELF_BUILD_ID: build_id,
+    }
+
+    if output_directory:
+      relative_to_out = lambda path: os.path.relpath(path, output_directory)
+      gn_args = _ParseGnArgs(os.path.join(output_directory, 'args.gn'))
+      metadata[models.METADATA_MAP_FILENAME] = relative_to_out(map_path)
+      metadata[models.METADATA_ELF_FILENAME] = relative_to_out(elf_path)
+      metadata[models.METADATA_GN_ARGS] = gn_args
+
+      if apk_path:
+        metadata[models.METADATA_APK_FILENAME] = relative_to_out(apk_path)
+  return metadata
+
+
+def CreateSizeInfo(map_path, elf_path, tool_prefix, output_directory,
                    raw_only=False):
-  """Creates a SizeInfo from the given map file."""
-  # tool_prefix needed for c++filt.
-  lazy_paths.VerifyToolPrefix()
+  """Creates a SizeInfo.
 
-  if not no_source_paths:
-    # Parse .ninja files at the same time as parsing the .map file.
-    source_mapper_result = helpers.ForkAndCall(
-        ninja_parser.Parse, lazy_paths.VerifyOutputDirectory())
+  Args:
+    map_path: Path to the linker .map(.gz) file to parse.
+    elf_path: Path to the corresponding unstripped ELF file. Used to find symbol
+        aliases and inlined functions. Can be None.
+    tool_prefix: Prefix for c++filt & nm (required).
+    output_directory: Build output directory. If None, source_paths and symbol
+        alias information will not be recorded.
+    raw_only: Fill in just the information required for creating a .size file.
+  """
+  source_mapper = None
+  if output_directory:
+    # Start by finding the elf_object_paths, so that nm can run on them while
+    # the linker .map is being parsed.
+    logging.info('Parsing ninja files.')
+    source_mapper, elf_object_paths = ninja_parser.Parse(
+        output_directory, elf_path)
+    assert not elf_path or elf_object_paths, (
+        'Failed to find link command in ninja files for ' +
+        os.path.relpath(elf_path, output_directory))
+
+  if elf_path:
+    # Run nm on the elf file to retrieve the list of symbol names per-address.
+    # This list is required because the .map file contains only a single name
+    # for each address, yet multiple symbols are often coalesced when they are
+    # identical. This coalescing happens mainly for small symbols and for C++
+    # templates. Such symbols make up ~500kb of libchrome.so on Android.
+    elf_nm_result = nm.CollectAliasesByAddressAsync(elf_path, tool_prefix)
+
+    # Run nm on all .o/.a files to retrieve the symbol names within them.
+    # The list is used to detect when mutiple .o files contain the same symbol
+    # (e.g. inline functions), and to update the object_path / source_path
+    # fields accordingly.
+    # Looking in object files is required because the .map file choses a
+    # single path for these symbols.
+    # Rather than record all paths for each symbol, set the paths to be the
+    # common ancestor of all paths.
+    if output_directory:
+      bulk_analyzer = nm.BulkObjectFileAnalyzer(tool_prefix, output_directory)
+      bulk_analyzer.AnalyzePaths(elf_object_paths)
 
   with _OpenMaybeGz(map_path) as map_file:
     section_sizes, raw_symbols = (
         linker_map_parser.MapFileParser().Parse(map_file))
 
-  if not no_source_paths:
-    logging.info('Extracting source paths from .ninja files')
-    source_mapper = source_mapper_result.get()
+  if elf_path:
+    logging.debug('Validating section sizes')
+    elf_section_sizes = _SectionSizesFromElf(elf_path, tool_prefix)
+    for k, v in elf_section_sizes.iteritems():
+      if v != section_sizes.get(k):
+        logging.error('ELF file and .map file do not agree on section sizes.')
+        logging.error('.map file: %r', section_sizes)
+        logging.error('readelf: %r', elf_section_sizes)
+        sys.exit(1)
+
+  if elf_path and output_directory:
+    missed_object_paths = _DiscoverMissedObjectPaths(
+        raw_symbols, elf_object_paths)
+    bulk_analyzer.AnalyzePaths(missed_object_paths)
+    bulk_analyzer.Close()
+
+  if source_mapper:
+    logging.info('Looking up source paths from ninja files')
     _ExtractSourcePaths(raw_symbols, source_mapper)
     assert source_mapper.unmatched_paths_count == 0, (
         'One or more source file paths could not be found. Likely caused by '
         '.ninja files being generated at a different time than the .map file.')
 
   logging.info('Stripping linker prefixes from symbol names')
   _StripLinkerAddedSymbolPrefixes(raw_symbols)
   # Map file for some reason doesn't unmangle all names.
   # Unmangle prints its own log statement.
-  _UnmangleRemainingSymbols(raw_symbols, lazy_paths.tool_prefix)
-  logging.info('Normalizing object paths')
-  _NormalizeObjectPaths(raw_symbols)
+  _UnmangleRemainingSymbols(raw_symbols, tool_prefix)
+
+  if elf_path:
+    logging.info('Adding aliased symbols, as reported by nm')
+    # This normally does not block (it's finished by this time).
+    aliases_by_address = elf_nm_result.get()
+    _AddSymbolAliases(raw_symbols, aliases_by_address)
+
+    if output_directory:
+      # For aliases, this provides path information where there wasn't any.
+      logging.info('Computing ancestor paths for inline functions and '
+                   'normalizing object paths')
+
+      object_paths_by_name = bulk_analyzer.Get()
+      logging.debug('Fetched path information for %d symbols from %d files',
+                    len(object_paths_by_name),
+                    len(elf_object_paths) + len(missed_object_paths))
+      _ComputeAnscestorPathsAndNormalizeObjectPaths(
+          raw_symbols, object_paths_by_name, source_mapper)
+
+  if not elf_path or not output_directory:
+    logging.info('Normalizing object paths.')
+    for symbol in raw_symbols:
+      symbol.object_path = _NormalizeObjectPath(symbol.object_path)
+
   size_info = models.SizeInfo(section_sizes, raw_symbols)
 
   # Name normalization not strictly required, but makes for smaller files.
   if raw_only:
     logging.info('Normalizing symbol names')
     _NormalizeNames(size_info.raw_symbols)
   else:
     _PostProcessSizeInfo(size_info)
 
   if logging.getLogger().isEnabledFor(logging.DEBUG):
@@ skipping 102 matching lines @@
                                any_path_within_output_directory=any_input)
   if apk_path:
     with zipfile.ZipFile(apk_path) as z:
       lib_infos = [f for f in z.infolist()
                    if f.filename.endswith('.so') and f.file_size > 0]
     assert lib_infos, 'APK has no .so files.'
     # TODO(agrieve): Add support for multiple .so files, and take into account
     #     secondary architectures.
     apk_so_path = max(lib_infos, key=lambda x:x.file_size).filename
     logging.debug('Sub-apk path=%s', apk_so_path)
-    if not elf_path:
+    if not elf_path and lazy_paths.output_directory:
       elf_path = os.path.join(
           lazy_paths.output_directory, 'lib.unstripped',
           os.path.basename(apk_so_path.replace('crazy.', '')))
       logging.debug('Detected --elf-file=%s', elf_path)
 
   if map_path:
     if not map_path.endswith('.map') and not map_path.endswith('.map.gz'):
       parser.error('Expected --map-file to end with .map or .map.gz')
   else:
     map_path = elf_path + '.map'
     if not os.path.exists(map_path):
       map_path += '.gz'
     if not os.path.exists(map_path):
       parser.error('Could not find .map(.gz)? file. Use --map-file.')
 
-  metadata = None
-  if elf_path:
-    logging.debug('Constructing metadata')
-    git_rev = _DetectGitRevision(os.path.dirname(elf_path))
-    architecture = _ArchFromElf(elf_path, lazy_paths.tool_prefix)
-    build_id = BuildIdFromElf(elf_path, lazy_paths.tool_prefix)
-    timestamp_obj = datetime.datetime.utcfromtimestamp(os.path.getmtime(
-        elf_path))
-    timestamp = calendar.timegm(timestamp_obj.timetuple())
-    gn_args = _ParseGnArgs(os.path.join(lazy_paths.output_directory, 'args.gn'))
+  tool_prefix = lazy_paths.VerifyToolPrefix()
+  output_directory = None
+  if not args.no_source_paths:
+    output_directory = lazy_paths.VerifyOutputDirectory()
 
-    def relative_to_out(path):
-      return os.path.relpath(path, lazy_paths.VerifyOutputDirectory())
-
-    metadata = {
-        models.METADATA_GIT_REVISION: git_rev,
-        models.METADATA_MAP_FILENAME: relative_to_out(map_path),
-        models.METADATA_ELF_ARCHITECTURE: architecture,
-        models.METADATA_ELF_FILENAME: relative_to_out(elf_path),
-        models.METADATA_ELF_MTIME: timestamp,
-        models.METADATA_ELF_BUILD_ID: build_id,
-        models.METADATA_GN_ARGS: gn_args,
-    }
-
-    if apk_path:
-      metadata[models.METADATA_APK_FILENAME] = relative_to_out(apk_path)
-      # Extraction takes around 1 second, so do it in parallel.
-      apk_elf_result = helpers.ForkAndCall(
-          _ElfInfoFromApk, apk_path, apk_so_path, lazy_paths.tool_prefix)
+  metadata = CreateMetadata(map_path, elf_path, apk_path, tool_prefix,
+                            output_directory)
+  if apk_path and elf_path:
+    # Extraction takes around 1 second, so do it in parallel.
+    apk_elf_result = concurrent.ForkAndCall(
+        _ElfInfoFromApk, (apk_path, apk_so_path, tool_prefix))
 
   size_info = CreateSizeInfo(
-      map_path, lazy_paths, no_source_paths=args.no_source_paths, raw_only=True)
+      map_path, elf_path, tool_prefix, output_directory, raw_only=True)
 
   if metadata:
     size_info.metadata = metadata
-    logging.debug('Validating section sizes')
-    elf_section_sizes = _SectionSizesFromElf(elf_path, lazy_paths.tool_prefix)
-    for k, v in elf_section_sizes.iteritems():
-      assert v == size_info.section_sizes.get(k), (
-          'ELF file and .map file do not match.')
 
     if apk_path:
       logging.debug('Extracting section sizes from .so within .apk')
       unstripped_section_sizes = size_info.section_sizes
       apk_build_id, size_info.section_sizes = apk_elf_result.get()
-      assert apk_build_id == build_id, (
+      assert apk_build_id == metadata[models.METADATA_ELF_BUILD_ID], (
           'BuildID for %s within %s did not match the one at %s' %
           (apk_so_path, apk_path, elf_path))
 
       packed_section_name = None
+      architecture = metadata[models.METADATA_ELF_ARCHITECTURE]
       if architecture == 'ARM':
         packed_section_name = '.rel.dyn'
       elif architecture == 'AArch64':
         packed_section_name = '.rela.dyn'
 
       if packed_section_name:
         logging.debug('Recording size of unpacked relocations')
         if packed_section_name not in size_info.section_sizes:
           logging.warning('Packed section not present: %s', packed_section_name)
         else:
           size_info.section_sizes['%s (unpacked)' % packed_section_name] = (
               unstripped_section_sizes.get(packed_section_name))
 
   logging.info('Recording metadata: \n  %s',
                '\n  '.join(describe.DescribeMetadata(size_info.metadata)))
   logging.info('Saving result to %s', args.size_file)
   file_format.SaveSizeInfo(size_info, args.size_file)
   logging.info('Done')