diff --git a/tools/binary_size/libsupersize/archive.py b/tools/binary_size/libsupersize/archive.py
index b1da8c7fec1351..e5efbeca5dfbf6 100644
--- a/tools/binary_size/libsupersize/archive.py
+++ b/tools/binary_size/libsupersize/archive.py
@@ -725,9 +725,9 @@ def _ExtendSectionRange(section_range_by_name, section_name, delta_size):
   section_range_by_name[section_name] = (prev_address, prev_size + delta_size)
 
 
-def CreateMetadata(map_path, elf_path, apk_path, minimal_apks_path,
-                   tool_prefix, output_directory, linker_name):
-  """Creates metadata dict.
+def CreateMetadata(map_path, elf_path, apk_path, minimal_apks_path, tool_prefix,
+                   output_directory, linker_name, build_config):
+  """Creates metadata dict while updating |build_config|.
 
   Args:
     map_path: Path to the linker .map(.gz) file to parse.
@@ -738,6 +738,8 @@ def CreateMetadata(map_path, elf_path, apk_path, minimal_apks_path,
     tool_prefix: Prefix for c++filt & nm.
     output_directory: Build output directory.
     linker_name: A coded linker name (see linker_map_parser.py).
+    builg_config: Common build configurations to update or to undergo
+        consistency checks.
 
   Returns:
     A dict mapping string costants to values, or None if empty. Performs
@@ -748,21 +750,31 @@ def CreateMetadata(map_path, elf_path, apk_path, minimal_apks_path,
   """
   assert not (apk_path and minimal_apks_path)
   logging.debug('Constructing metadata')
+
+  def update_build_config(key, value):
+    if key in build_config:
+      old_value = build_config[key]
+      if value != old_value:
+        raise ValueError('Inconsistent {}: {} (was {})'.format(
+            key, value, old_value))
+    else:
+      build_config[key] = value
+
   metadata = {}
 
   if output_directory:
     shorten_path = lambda path: os.path.relpath(path, output_directory)
     gn_args = _ParseGnArgs(os.path.join(output_directory, 'args.gn'))
-    metadata[models.METADATA_GN_ARGS] = gn_args
+    update_build_config(models.BUILD_CONFIG_GN_ARGS, gn_args)
   else:
     shorten_path = os.path.basename
 
   if tool_prefix:
     relative_tool_prefix = path_util.ToToolsSrcRootRelative(tool_prefix)
-    metadata[models.METADATA_TOOL_PREFIX] = relative_tool_prefix
+    update_build_config(models.BUILD_CONFIG_TOOL_PREFIX, relative_tool_prefix)
 
   if linker_name:
-    metadata[models.METADATA_LINKER_NAME] = linker_name
+    update_build_config(models.BUILD_CONFIG_LINKER_NAME, linker_name)
 
   # Deduce GIT revision.
   path_candidates = [elf_path, apk_path, minimal_apks_path]
@@ -774,8 +786,7 @@ def CreateMetadata(map_path, elf_path, apk_path, minimal_apks_path,
       if dirname:
         git_rev = _DetectGitRevision(dirname)
         if git_rev:
-          metadata[models.METADATA_GIT_REVISION] = git_rev
-          break
+          update_build_config(models.BUILD_CONFIG_GIT_REVISION, git_rev)
 
   if elf_path:
     metadata[models.METADATA_ELF_FILENAME] = shorten_path(elf_path)
@@ -1405,6 +1416,7 @@ def _AddUnattributedSectionSymbols(raw_symbols, section_ranges):
 
 def CreateSectionSizesAndSymbols(knobs=None,
                                  opts=None,
+                                 metadata=None,
                                  map_path=None,
                                  tool_prefix=None,
                                  output_directory=None,
@@ -1413,7 +1425,6 @@ def CreateSectionSizesAndSymbols(knobs=None,
                                  mapping_path=None,
                                  resources_pathmap_path=None,
                                  track_string_literals=True,
-                                 metadata=None,
                                  apk_so_path=None,
                                  pak_files=None,
                                  pak_info_file=None,
@@ -1424,6 +1435,7 @@ def CreateSectionSizesAndSymbols(knobs=None,
   Args:
     knobs: Instance of SectionSizeKnobs.
     opts: Instance of ContainerArchiveOptions.
+    metadata: Metadata dict from CreateMetadata().
     map_path: Path to the linker .map(.gz) file to parse.
     tool_prefix: Prefix for c++filt & nm (required).
     output_directory: Build output directory. If None, source_paths and symbol
@@ -1436,7 +1448,6 @@ def CreateSectionSizesAndSymbols(knobs=None,
         resource paths to shortened resource paths.
     track_string_literals: Whether to break down "** merge string" sections into
         smaller symbols (requires output_directory).
-    metadata: Metadata dict from CreateMetadata().
     apk_so_path: Path to an .so file within an APK file.
     pak_files: List of paths to .pak files.
     pak_info_file: Path to a .pak.info file.
@@ -1600,7 +1611,8 @@ def CreateSectionSizesAndSymbols(knobs=None,
   return section_sizes, raw_symbols
 
 
-def CreateSizeInfo(section_sizes_list,
+def CreateSizeInfo(build_config,
+                   section_sizes_list,
                    raw_symbols_list,
                    metadata_list,
                    normalize_names=True):
@@ -1621,7 +1633,10 @@ def CreateSizeInfo(section_sizes_list,
   raw_symbols = raw_symbols_list[0]
   metadata = metadata_list[0]
 
-  return models.SizeInfo(section_sizes, raw_symbols, metadata=metadata)
+  return models.SizeInfo(build_config,
+                         section_sizes,
+                         raw_symbols,
+                         metadata=metadata)
 
 
 def _DetectGitRevision(directory):
@@ -1927,7 +1942,6 @@ def _Inner(sub_args, apk_prefix, apk_path):
             apk_so_path, elf_path, map_path, resources_pathmap_path,
             linker_name, size_info_prefix)
 
-  # Process each container.
   # If needed, extract .apk file to a temp file and process that instead.
   if args.minimal_apks_file:
     with zip_util.UnzipToTemp(args.minimal_apks_file, _APKS_MAIN_APK) as temp:
@@ -1958,6 +1972,7 @@ def Run(args, on_config_error):
 
   knobs = SectionSizeKnobs()
 
+  build_config = {}
   metadata_list = []
   section_sizes_list = []
   raw_symbols_list = []
@@ -1969,10 +1984,11 @@ def Run(args, on_config_error):
     # may be an extracted temporary file.
     metadata = CreateMetadata(map_path, elf_path, args.apk_file,
                               args.minimal_apks_file, tool_prefix,
-                              output_directory, linker_name)
+                              output_directory, linker_name, build_config)
     section_sizes, raw_symbols = CreateSectionSizesAndSymbols(
         knobs=knobs,
         opts=opts,
+        metadata=metadata,
         map_path=map_path,
         tool_prefix=tool_prefix,
         elf_path=elf_path,
@@ -1981,7 +1997,6 @@ def Run(args, on_config_error):
         output_directory=output_directory,
         resources_pathmap_path=resources_pathmap_path,
         track_string_literals=args.track_string_literals,
-        metadata=metadata,
         apk_so_path=apk_so_path,
         pak_files=args.pak_file,
         pak_info_file=args.pak_info_file,
@@ -1992,18 +2007,18 @@ def Run(args, on_config_error):
     section_sizes_list.append(section_sizes)
     raw_symbols_list.append(raw_symbols)
 
-  size_info = CreateSizeInfo(
-      section_sizes_list,
-      raw_symbols_list,
-      metadata_list,
-      normalize_names=False)
+  size_info = CreateSizeInfo(build_config,
+                             section_sizes_list,
+                             raw_symbols_list,
+                             metadata_list,
+                             normalize_names=False)
 
   if logging.getLogger().isEnabledFor(logging.DEBUG):
     for line in describe.DescribeSizeInfoCoverage(size_info):
       logging.debug(line)
   logging.info('Recorded info for %d symbols', len(size_info.raw_symbols))
-  logging.info('Recording metadata: \n  %s', '\n  '.join(
-      describe.DescribeMetadata(size_info.metadata)))
+  logging.info('Recording metadata: \n  %s',
+               '\n  '.join(describe.DescribeDict(size_info.metadata)))
 
   logging.info('Saving result to %s', args.size_file)
   file_format.SaveSizeInfo(
diff --git a/tools/binary_size/libsupersize/console.py b/tools/binary_size/libsupersize/console.py
index f8ef12e0b6269c..5cef3ecd5b87a9 100644
--- a/tools/binary_size/libsupersize/console.py
+++ b/tools/binary_size/libsupersize/console.py
@@ -126,8 +126,7 @@ def _ReadStringLiterals(self, thing=None, all_rodata=False, elf_path=None):
       return []
     size_info = self._SizeInfoForSymbol(first_sym)
     tool_prefix = self._ToolPrefixForSymbol(size_info)
-    elf_path = self._ElfPathForSymbol(
-        size_info, tool_prefix, elf_path)
+    elf_path = self._ElfPathForSymbol(size_info, tool_prefix, elf_path)
 
     return string_extract.ReadStringLiterals(
         thing, elf_path, tool_prefix, all_rodata=all_rodata)
@@ -243,7 +242,8 @@ def _CsvFunc(self, obj=None, verbose=False, use_pager=None, to_file=None):
 
   def _ToolPrefixForSymbol(self, size_info):
     tool_prefix = self._tool_prefix_finder.Tentative()
-    orig_tool_prefix = size_info.metadata.get(models.METADATA_TOOL_PREFIX)
+    orig_tool_prefix = size_info.build_config.get(
+        models.BUILD_CONFIG_TOOL_PREFIX)
     if orig_tool_prefix:
       orig_tool_prefix = path_util.FromToolsSrcRootRelative(orig_tool_prefix)
       if os.path.exists(path_util.GetObjDumpPath(orig_tool_prefix)):
@@ -489,7 +489,7 @@ def Run(args, on_config_error):
   output_directory_finder = path_util.OutputDirectoryFinder(
       value=args.output_directory,
       any_path_within_output_directory=args.inputs[0])
-  linker_name = size_infos[-1].metadata.get(models.METADATA_LINKER_NAME)
+  linker_name = size_infos[-1].build_config.get(models.BUILD_CONFIG_LINKER_NAME)
   tool_prefix_finder = path_util.ToolPrefixFinder(
       value=args.tool_prefix,
       output_directory_finder=output_directory_finder,
diff --git a/tools/binary_size/libsupersize/describe.py b/tools/binary_size/libsupersize/describe.py
index 83eb04ddb6ab17..2e5e93f105d073 100644
--- a/tools/binary_size/libsupersize/describe.py
+++ b/tools/binary_size/libsupersize/describe.py
@@ -489,27 +489,28 @@ def _DescribeDeltaSymbolGroup(self, delta_group):
     group_desc = self._DescribeSymbolGroup(delta_group)
     return itertools.chain(diff_summary_desc, path_delta_desc, group_desc)
 
-  def _DescribeDeltaSizeInfo(self, diff):
-    common_metadata = {
-        k: v
-        for k, v in diff.before.metadata.items()
-        if diff.after.metadata.get(k) == v
-    }
-    before_metadata = {
+  def _DescribeDeltaDict(self, data_name, before_dict, after_dict):
+    common_items = {
         k: v
-        for k, v in diff.before.metadata.items() if k not in common_metadata
+        for k, v in before_dict.items() if after_dict.get(k) == v
     }
-    after_metadata = {
+    before_items = {
         k: v
-        for k, v in diff.after.metadata.items() if k not in common_metadata
+        for k, v in before_dict.items() if k not in common_items
     }
-    metadata_desc = itertools.chain(
-        ('Common Metadata:',),
-        ('    %s' % line for line in DescribeMetadata(common_metadata)),
-        ('Old Metadata:',),
-        ('    %s' % line for line in DescribeMetadata(before_metadata)),
-        ('New Metadata:',),
-        ('    %s' % line for line in DescribeMetadata(after_metadata)))
+    after_items = {k: v for k, v in after_dict.items() if k not in common_items}
+    return itertools.chain(
+        ('Common %s:' % data_name, ), ('    %s' % line
+                                       for line in DescribeDict(common_items)),
+        ('Old %s:' % data_name, ), ('    %s' % line
+                                    for line in DescribeDict(before_items)),
+        ('New %s:' % data_name, ), ('    %s' % line
+                                    for line in DescribeDict(after_items)))
+
+  def _DescribeDeltaSizeInfo(self, diff):
+    metadata_desc = self._DescribeDeltaDict('Metadata',
+                                            diff.before.metadata_legacy,
+                                            diff.after.metadata_legacy)
     unsummed_sections, summed_sections = diff.ClassifySections()
     section_desc = self._DescribeSectionSizes(unsummed_sections,
                                               summed_sections,
@@ -518,9 +519,10 @@ def _DescribeDeltaSizeInfo(self, diff):
     return itertools.chain(metadata_desc, section_desc, ('',), group_desc)
 
   def _DescribeSizeInfo(self, size_info):
+    # Support legacy output by reporting |build_config| as part of metadata.
     metadata_desc = itertools.chain(
-        ('Metadata:',),
-        ('    %s' % line for line in DescribeMetadata(size_info.metadata)))
+        ('Metadata:', ),
+        ('    %s' % line for line in DescribeDict(size_info.metadata_legacy)))
     unsummed_sections, summed_sections = size_info.ClassifySections()
     section_desc = self._DescribeSectionSizes(unsummed_sections,
                                               summed_sections,
@@ -744,16 +746,25 @@ def _UtcToLocal(utc):
   return utc + offset
 
 
-def DescribeMetadata(metadata):
-  display_dict = metadata.copy()
-  timestamp = display_dict.get(models.METADATA_ELF_MTIME)
-  if timestamp:
-    timestamp_obj = datetime.datetime.utcfromtimestamp(timestamp)
-    display_dict[models.METADATA_ELF_MTIME] = (
-        _UtcToLocal(timestamp_obj).strftime('%Y-%m-%d %H:%M:%S'))
-  gn_args = display_dict.get(models.METADATA_GN_ARGS)
-  if gn_args:
-    display_dict[models.METADATA_GN_ARGS] = ' '.join(gn_args)
+def DescribeDict(input_dict):
+  display_dict = {}
+  for k, v in input_dict.items():
+    if k == models.METADATA_ELF_MTIME:
+      timestamp_obj = datetime.datetime.utcfromtimestamp(v)
+      display_dict[k] = (
+          _UtcToLocal(timestamp_obj).strftime('%Y-%m-%d %H:%M:%S'))
+    elif isinstance(v, str):
+      display_dict[k] = v
+    elif isinstance(v, list):
+      if v:
+        if isinstance(v[0], str):
+          display_dict[k] = ' '.join(str(t) for t in v)
+        else:
+          display_dict[k] = repr(v)
+      else:
+        display_dict[k] = ''
+    else:
+      display_dict[k] = repr(v)
   return sorted('%s=%s' % t for t in display_dict.items())
 
 
diff --git a/tools/binary_size/libsupersize/diff_test.py b/tools/binary_size/libsupersize/diff_test.py
index 80a4d8996e66d2..0d641c4c6ecb1f 100755
--- a/tools/binary_size/libsupersize/diff_test.py
+++ b/tools/binary_size/libsupersize/diff_test.py
@@ -31,6 +31,7 @@ def _SetName(symbol, full_name, name=None):
 
 
 def _CreateSizeInfo(aliases=None):
+  build_config = {}
   section_sizes = {'.text': 100, '.bss': 40}
   TEXT = models.SECTION_TEXT
   symbols = [
@@ -46,7 +47,7 @@ def _CreateSizeInfo(aliases=None):
       syms = symbols[tup[0]:tup[1]]
       for sym in syms:
         sym.aliases = syms
-  return models.SizeInfo(section_sizes, symbols)
+  return models.SizeInfo(build_config, section_sizes, symbols)
 
 
 class DiffTest(unittest.TestCase):
@@ -55,27 +56,27 @@ def testIdentity(self):
     size_info1 = _CreateSizeInfo()
     size_info2 = _CreateSizeInfo()
     d = diff.Diff(size_info1, size_info2)
-    self.assertEquals((0, 0, 0), d.raw_symbols.CountsByDiffStatus()[1:])
-    self.assertEquals(0, d.raw_symbols.size)
-    self.assertEquals(0, d.raw_symbols.padding)
+    self.assertEqual((0, 0, 0), d.raw_symbols.CountsByDiffStatus()[1:])
+    self.assertEqual(0, d.raw_symbols.size)
+    self.assertEqual(0, d.raw_symbols.padding)
 
   def testSimple_Add(self):
     size_info1 = _CreateSizeInfo()
     size_info2 = _CreateSizeInfo()
     size_info1.raw_symbols -= [size_info1.raw_symbols[0]]
     d = diff.Diff(size_info1, size_info2)
-    self.assertEquals((0, 1, 0), d.raw_symbols.CountsByDiffStatus()[1:])
-    self.assertEquals(10, d.raw_symbols.size)
-    self.assertEquals(0, d.raw_symbols.padding)
+    self.assertEqual((0, 1, 0), d.raw_symbols.CountsByDiffStatus()[1:])
+    self.assertEqual(10, d.raw_symbols.size)
+    self.assertEqual(0, d.raw_symbols.padding)
 
   def testSimple_Delete(self):
     size_info1 = _CreateSizeInfo()
     size_info2 = _CreateSizeInfo()
     size_info2.raw_symbols -= [size_info2.raw_symbols[0]]
     d = diff.Diff(size_info1, size_info2)
-    self.assertEquals((0, 0, 1), d.raw_symbols.CountsByDiffStatus()[1:])
-    self.assertEquals(-10, d.raw_symbols.size)
-    self.assertEquals(0, d.raw_symbols.padding)
+    self.assertEqual((0, 0, 1), d.raw_symbols.CountsByDiffStatus()[1:])
+    self.assertEqual(-10, d.raw_symbols.size)
+    self.assertEqual(0, d.raw_symbols.padding)
 
   def testSimple_Change(self):
     size_info1 = _CreateSizeInfo()
@@ -84,9 +85,9 @@ def testSimple_Change(self):
     size_info2.raw_symbols[0].padding += 20
     size_info2.raw_symbols[-1].size += 11
     d = diff.Diff(size_info1, size_info2)
-    self.assertEquals((2, 1, 0), d.raw_symbols.CountsByDiffStatus()[1:])
-    self.assertEquals(22, d.raw_symbols.size)
-    self.assertEquals(20, d.raw_symbols.padding)
+    self.assertEqual((2, 1, 0), d.raw_symbols.CountsByDiffStatus()[1:])
+    self.assertEqual(22, d.raw_symbols.size)
+    self.assertEqual(20, d.raw_symbols.padding)
 
   def testDontMatchAcrossSections(self):
     size_info1 = _CreateSizeInfo()
@@ -98,32 +99,32 @@ def testDontMatchAcrossSections(self):
         _MakeSym(models.SECTION_RODATA, 11, 'asdf', name='Hello'),
     ]
     d = diff.Diff(size_info1, size_info2)
-    self.assertEquals((0, 1, 1), d.raw_symbols.CountsByDiffStatus()[1:])
-    self.assertEquals(0, d.raw_symbols.size)
+    self.assertEqual((0, 1, 1), d.raw_symbols.CountsByDiffStatus()[1:])
+    self.assertEqual(0, d.raw_symbols.size)
 
   def testAliases_Remove(self):
     size_info1 = _CreateSizeInfo(aliases=[(0, 3)])
     size_info2 = _CreateSizeInfo(aliases=[(0, 2)])
     d = diff.Diff(size_info1, size_info2)
     # Aliases cause all sizes to change.
-    self.assertEquals((3, 0, 0), d.raw_symbols.CountsByDiffStatus()[1:])
-    self.assertEquals(0, d.raw_symbols.size)
+    self.assertEqual((3, 0, 0), d.raw_symbols.CountsByDiffStatus()[1:])
+    self.assertEqual(0, d.raw_symbols.size)
 
   def testAliases_Add(self):
     size_info1 = _CreateSizeInfo(aliases=[(0, 2)])
     size_info2 = _CreateSizeInfo(aliases=[(0, 3)])
     d = diff.Diff(size_info1, size_info2)
     # Aliases cause all sizes to change.
-    self.assertEquals((3, 0, 0), d.raw_symbols.CountsByDiffStatus()[1:])
-    self.assertEquals(0, d.raw_symbols.size)
+    self.assertEqual((3, 0, 0), d.raw_symbols.CountsByDiffStatus()[1:])
+    self.assertEqual(0, d.raw_symbols.size)
 
   def testAliases_ChangeGroup(self):
     size_info1 = _CreateSizeInfo(aliases=[(0, 2), (2, 5)])
     size_info2 = _CreateSizeInfo(aliases=[(0, 3), (3, 5)])
     d = diff.Diff(size_info1, size_info2)
     # Aliases cause all sizes to change.
-    self.assertEquals((4, 0, 0), d.raw_symbols.CountsByDiffStatus()[1:])
-    self.assertEquals(0, d.raw_symbols.size)
+    self.assertEqual((4, 0, 0), d.raw_symbols.CountsByDiffStatus()[1:])
+    self.assertEqual(0, d.raw_symbols.size)
 
   def testStarSymbolNormalization(self):
     size_info1 = _CreateSizeInfo()
@@ -131,8 +132,8 @@ def testStarSymbolNormalization(self):
     size_info2 = _CreateSizeInfo()
     _SetName(size_info2.raw_symbols[0], '* symbol gap 2 (end of section)')
     d = diff.Diff(size_info1, size_info2)
-    self.assertEquals((0, 0, 0), d.raw_symbols.CountsByDiffStatus()[1:])
-    self.assertEquals(0, d.raw_symbols.size)
+    self.assertEqual((0, 0, 0), d.raw_symbols.CountsByDiffStatus()[1:])
+    self.assertEqual(0, d.raw_symbols.size)
 
   def testNumberNormalization(self):
     TEXT = models.SECTION_TEXT
@@ -151,8 +152,8 @@ def testNumberNormalization(self):
         _MakeSym(TEXT, 44, 'a', name='.L.ref.tmp.137'),
     ]
     d = diff.Diff(size_info1, size_info2)
-    self.assertEquals((0, 0, 0), d.raw_symbols.CountsByDiffStatus()[1:])
-    self.assertEquals(0, d.raw_symbols.size)
+    self.assertEqual((0, 0, 0), d.raw_symbols.CountsByDiffStatus()[1:])
+    self.assertEqual(0, d.raw_symbols.size)
 
   def testChangedParams(self):
     # Ensure that params changes match up so long as path doesn't change.
@@ -163,8 +164,8 @@ def testChangedParams(self):
     size_info2.raw_symbols[0].full_name = 'Foo(bool)'
     size_info2.raw_symbols[0].name = 'Foo'
     d = diff.Diff(size_info1, size_info2)
-    self.assertEquals((0, 0, 0), d.raw_symbols.CountsByDiffStatus()[1:])
-    self.assertEquals(0, d.raw_symbols.size)
+    self.assertEqual((0, 0, 0), d.raw_symbols.CountsByDiffStatus()[1:])
+    self.assertEqual(0, d.raw_symbols.size)
 
   def testChangedPaths_Native(self):
     # Ensure that non-globally-unique symbols are not matched when path changes.
@@ -172,8 +173,8 @@ def testChangedPaths_Native(self):
     size_info2 = _CreateSizeInfo()
     size_info2.raw_symbols[1].object_path = 'asdf'
     d = diff.Diff(size_info1, size_info2)
-    self.assertEquals((0, 1, 1), d.raw_symbols.CountsByDiffStatus()[1:])
-    self.assertEquals(0, d.raw_symbols.size)
+    self.assertEqual((0, 1, 1), d.raw_symbols.CountsByDiffStatus()[1:])
+    self.assertEqual(0, d.raw_symbols.size)
 
   def testChangedPaths_StringLiterals(self):
     # Ensure that string literals are not matched up.
@@ -183,8 +184,8 @@ def testChangedPaths_StringLiterals(self):
     size_info2.raw_symbols[0].full_name = models.STRING_LITERAL_NAME
     size_info2.raw_symbols[0].object_path = 'asdf'
     d = diff.Diff(size_info1, size_info2)
-    self.assertEquals((0, 1, 1), d.raw_symbols.CountsByDiffStatus()[1:])
-    self.assertEquals(0, d.raw_symbols.size)
+    self.assertEqual((0, 1, 1), d.raw_symbols.CountsByDiffStatus()[1:])
+    self.assertEqual(0, d.raw_symbols.size)
 
   def testChangedPaths_Java(self):
     # Ensure that Java symbols are matched up.
@@ -192,8 +193,8 @@ def testChangedPaths_Java(self):
     size_info2 = _CreateSizeInfo()
     size_info2.raw_symbols[0].object_path = 'asdf'
     d = diff.Diff(size_info1, size_info2)
-    self.assertEquals((0, 0, 0), d.raw_symbols.CountsByDiffStatus()[1:])
-    self.assertEquals(0, d.raw_symbols.size)
+    self.assertEqual((0, 0, 0), d.raw_symbols.CountsByDiffStatus()[1:])
+    self.assertEqual(0, d.raw_symbols.size)
 
   def testChangedPaths_ChangedParams(self):
     # Ensure that path changes are not matched when params also change.
@@ -205,8 +206,8 @@ def testChangedPaths_ChangedParams(self):
     size_info2.raw_symbols[0].name = 'Foo'
     size_info2.raw_symbols[0].object_path = 'asdf'
     d = diff.Diff(size_info1, size_info2)
-    self.assertEquals((0, 1, 1), d.raw_symbols.CountsByDiffStatus()[1:])
-    self.assertEquals(0, d.raw_symbols.size)
+    self.assertEqual((0, 1, 1), d.raw_symbols.CountsByDiffStatus()[1:])
+    self.assertEqual(0, d.raw_symbols.size)
 
 
 
diff --git a/tools/binary_size/libsupersize/file_format.py b/tools/binary_size/libsupersize/file_format.py
index 20b5ec11383ab6..28120dba66655f 100644
--- a/tools/binary_size/libsupersize/file_format.py
+++ b/tools/binary_size/libsupersize/file_format.py
@@ -253,17 +253,25 @@ def _SaveSizeInfoToFile(size_info,
   w.WriteLine(_SERIALIZATION_VERSION)
   # JSON header fields
   fields = {
-      'metadata': size_info.metadata,
       'section_sizes': size_info.section_sizes,
       'has_components': True,
       'has_padding': include_padding,
   }
+  # Preserve old format: Combine build_config and metadata.
+  metadata = size_info.metadata
+  for key in models.BUILD_CONFIG_KEYS:
+    if key in size_info.build_config:
+      if not metadata:
+        metadata = {}
+      metadata[key] = size_info.build_config[key]
+  fields['metadata'] = metadata
+
   fields_str = json.dumps(fields, indent=2, sort_keys=True)
   w.WriteLine(str(len(fields_str)))
   w.WriteLine(fields_str)
   w.LogSize('header')  # For libchrome: 570 bytes.
 
-  # Store a single copy of all paths and have them referenced by index.
+  # Store a single copy of all paths and reference them by index.
   unique_path_tuples = sorted(
       set((s.object_path, s.source_path) for s in raw_symbols))
   path_tuples = {tup: i for i, tup in enumerate(unique_path_tuples)}
@@ -381,7 +389,16 @@ def _LoadSizeInfoFromFile(file_obj, size_path):
 
   fields = json.loads(json_str)
   section_sizes = fields['section_sizes']
+
+  # Parse old format, but separate data into build_config and metadata.
+  build_config = {}
   metadata = fields.get('metadata')
+  if metadata:
+    for key in models.BUILD_CONFIG_KEYS:
+      if key in metadata:
+        build_config[key] = metadata[key]
+        del metadata[key]
+
   has_components = fields.get('has_components', False)
   has_padding = fields.get('has_padding', False)
 
@@ -505,7 +522,10 @@ def read_numeric(delta=False):
   if not has_padding:
     CalculatePadding(raw_symbols)
 
-  return models.SizeInfo(section_sizes, raw_symbols, metadata=metadata,
+  return models.SizeInfo(build_config,
+                         section_sizes,
+                         raw_symbols,
+                         metadata=metadata,
                          size_path=size_path)
 
 
diff --git a/tools/binary_size/libsupersize/integration_test.py b/tools/binary_size/libsupersize/integration_test.py
index 805ea14945aee1..4cf9f22dfa0505 100755
--- a/tools/binary_size/libsupersize/integration_test.py
+++ b/tools/binary_size/libsupersize/integration_test.py
@@ -210,25 +210,27 @@ def _CloneSizeInfo(self, use_output_directory=True, use_elf=True,
         pak_info_file = _TEST_PAK_INFO_PATH
       linker_name = 'gold'
       with _AddMocksToPath():
+        build_config = {}
         metadata = archive.CreateMetadata(_TEST_MAP_PATH, elf_path, apk_path,
                                           minimal_apks_path, _TEST_TOOL_PREFIX,
-                                          output_directory, linker_name)
+                                          output_directory, linker_name,
+                                          build_config)
         section_sizes, raw_symbols = archive.CreateSectionSizesAndSymbols(
             knobs=knobs,
             opts=opts,
+            metadata=metadata,
             map_path=_TEST_MAP_PATH,
             tool_prefix=_TEST_TOOL_PREFIX,
-            elf_path=elf_path,
             output_directory=output_directory,
+            elf_path=elf_path,
             apk_path=apk_path or extracted_minimal_apk_path,
             apk_so_path=apk_so_path,
-            metadata=metadata,
             pak_files=pak_files,
             pak_info_file=pak_info_file,
             linker_name=linker_name,
             size_info_prefix=size_info_prefix)
         IntegrationTest.cached_size_info[cache_key] = archive.CreateSizeInfo(
-            [section_sizes], [raw_symbols], [metadata])
+            build_config, [section_sizes], [raw_symbols], [metadata])
     return copy.deepcopy(IntegrationTest.cached_size_info[cache_key])
 
   def _DoArchive(self,
@@ -301,11 +303,15 @@ def _DoArchiveTest(self,
 
     sym_strs = (repr(sym) for sym in size_info.symbols)
     stats = describe.DescribeSizeInfoCoverage(size_info)
-    if size_info.metadata:
-      metadata = describe.DescribeMetadata(size_info.metadata)
+    # Merge the its metadata into build_config.
+    merged_data = size_info.build_config.copy()
+    for k, v in size_info.metadata.items():
+      merged_data[k] = v
+    if merged_data:
+      merged_data_desc = describe.DescribeDict(merged_data)
     else:
-      metadata = []
-    return itertools.chain(metadata, stats, sym_strs)
+      merged_data_desc = []
+    return itertools.chain(merged_data_desc, stats, sym_strs)
 
   @_CompareWithGolden()
   def test_Archive(self):
@@ -395,8 +401,9 @@ def test_Idempotent(self):
   def test_Diff_Basic(self):
     size_info1 = self._CloneSizeInfo(use_elf=False, use_pak=True)
     size_info2 = self._CloneSizeInfo(use_elf=False, use_pak=True)
-    size_info1.metadata = {"foo": 1, "bar": [1,2,3], "baz": "yes"}
-    size_info2.metadata = {"foo": 1, "bar": [1,3], "baz": "yes"}
+    size_info2.build_config['git_revision'] = 'xyz789'
+    size_info1.metadata = {"foo": 1, "bar": [1, 2, 3], "baz": "yes"}
+    size_info2.metadata = {"foo": 1, "bar": [1, 3], "baz": "yes"}
 
     size_info1.raw_symbols -= size_info1.raw_symbols[:2]
     size_info2.raw_symbols -= size_info2.raw_symbols[-3:]
diff --git a/tools/binary_size/libsupersize/models.py b/tools/binary_size/libsupersize/models.py
index b680274b8c2330..9e7053a9ea99e5 100644
--- a/tools/binary_size/libsupersize/models.py
+++ b/tools/binary_size/libsupersize/models.py
@@ -37,7 +37,18 @@
 import match_util
 
 
-METADATA_GIT_REVISION = 'git_revision'
+BUILD_CONFIG_GIT_REVISION = 'git_revision'
+BUILD_CONFIG_GN_ARGS = 'gn_args'
+BUILD_CONFIG_LINKER_NAME = 'linker_name'
+BUILD_CONFIG_TOOL_PREFIX = 'tool_prefix'  # Path relative to SRC_ROOT.
+
+BUILD_CONFIG_KEYS = (
+    BUILD_CONFIG_GIT_REVISION,
+    BUILD_CONFIG_GN_ARGS,
+    BUILD_CONFIG_LINKER_NAME,
+    BUILD_CONFIG_TOOL_PREFIX,
+)
+
 METADATA_APK_FILENAME = 'apk_file_name'  # Path relative to output_directory.
 METADATA_APK_SIZE = 'apk_size'  # File size of apk in bytes.
 METADATA_MAP_FILENAME = 'map_file_name'  # Path relative to output_directory.
@@ -46,9 +57,6 @@
 METADATA_ELF_MTIME = 'elf_mtime'  # int timestamp in utc.
 METADATA_ELF_BUILD_ID = 'elf_build_id'
 METADATA_ELF_RELOCATIONS_COUNT = 'elf_relocations_count'
-METADATA_GN_ARGS = 'gn_args'
-METADATA_LINKER_NAME = 'linker_name'
-METADATA_TOOL_PREFIX = 'tool_prefix'  # Path relative to SRC_ROOT.
 
 # New sections should also be added to the SuperSize UI.
 SECTION_BSS = '.bss'
@@ -195,6 +203,7 @@ class BaseSizeInfo(object):
   """Base class for SizeInfo and DeltaSizeInfo.
 
   Fields:
+    build_config: A dict of build configurations.
     section_sizes: A dict of section_name -> size.
     raw_symbols: A SymbolGroup containing all top-level symbols (no groups).
     symbols: A SymbolGroup of all symbols, where symbols have been
@@ -205,6 +214,7 @@ class BaseSizeInfo(object):
     pak_symbols: Subset of |symbols| that are from pak files.
   """
   __slots__ = (
+      'build_config',
       'section_sizes',
       'raw_symbols',
       '_symbols',
@@ -213,9 +223,10 @@ class BaseSizeInfo(object):
       '_classified_sections',
   )
 
-  def __init__(self, section_sizes, raw_symbols, symbols=None):
+  def __init__(self, build_config, section_sizes, raw_symbols, symbols=None):
     if isinstance(raw_symbols, list):
       raw_symbols = SymbolGroup(raw_symbols)
+    self.build_config = build_config
     self.section_sizes = section_sizes  # E.g. {SECTION_TEXT: 0}
     self.raw_symbols = raw_symbols
     self._symbols = symbols
@@ -267,12 +278,29 @@ class SizeInfo(BaseSizeInfo):
       'size_path',
   )
 
-  def __init__(self, section_sizes, raw_symbols, metadata=None, symbols=None,
+  def __init__(self,
+               build_config,
+               section_sizes,
+               raw_symbols,
+               metadata=None,
+               symbols=None,
                size_path=None):
-    super(SizeInfo, self).__init__(section_sizes, raw_symbols, symbols=symbols)
+    super(SizeInfo, self).__init__(build_config,
+                                   section_sizes,
+                                   raw_symbols,
+                                   symbols=symbols)
     self.metadata = metadata or {}
     self.size_path = size_path
 
+  @property
+  def metadata_legacy(self):
+    """Returns |metadata| fused with |build_config|."""
+    metadata = self.metadata.copy()
+    for k, v in self.build_config.items():
+      assert k not in metadata
+      metadata[k] = v
+    return metadata
+
 
 class DeltaSizeInfo(BaseSizeInfo):
   """What you get when you Diff() two SizeInfo objects.
@@ -287,7 +315,7 @@ class DeltaSizeInfo(BaseSizeInfo):
   )
 
   def __init__(self, before, after, section_sizes, raw_symbols):
-    super(DeltaSizeInfo, self).__init__(section_sizes, raw_symbols)
+    super(DeltaSizeInfo, self).__init__(None, section_sizes, raw_symbols)
     self.before = before
     self.after = after
 
diff --git a/tools/binary_size/libsupersize/testdata/Console.golden b/tools/binary_size/libsupersize/testdata/Console.golden
index adbbf2c009a676..21052a86f09fa2 100644
--- a/tools/binary_size/libsupersize/testdata/Console.golden
+++ b/tools/binary_size/libsupersize/testdata/Console.golden
@@ -1,12 +1,12 @@
 ********************************************************************************
 Entering interactive Python shell. Quick reference:
 
-SizeInfo: ClassifySections, metadata, native_symbols, pak_symbols, raw_symbols, section_sizes, size_path, symbols
+SizeInfo: ClassifySections, build_config, metadata, metadata_legacy, native_symbols, pak_symbols, raw_symbols, section_sizes, size_path, symbols
 Symbol: FlagsString, IsBss, IsDelta, IsDex, IsGeneratedByToolchain, IsGroup, IsNameUnique, IsNative, IsOther, IsOverhead, IsPak, IsStringLiteral, IterLeafSymbols, SetName, address, aliases, component, end_address, flags, full_name, generated_source, is_anonymous, name, num_aliases, object_path, padding, padding_pss, pss, pss_without_padding, section, section_name, size, size_without_padding, source_path, template_name
 
 SymbolGroup (extends Symbol): CountUniqueSymbols, Filter, GroupedBy, GroupedByAliases, GroupedByComponent, GroupedByFullName, GroupedByName, GroupedByPath, GroupedBySectionName, Inverted, IterUniqueSymbols, Sorted, SortedByAddress, SortedByCount, SortedByName, WhereAddressInRange, WhereComponentMatches, WhereFullNameMatches, WhereGeneratedByToolchain, WhereHasAnyAttribution, WhereHasComponent, WhereHasFlag, WhereHasPath, WhereInSection, WhereIsDex, WhereIsGroup, WhereIsNative, WhereIsPak, WhereIsTemplate, WhereMatches, WhereNameMatches, WhereObjectPathMatches, WherePathMatches, WherePssBiggerThan, WhereSizeBiggerThan, WhereSourceIsGenerated, WhereSourcePathMatches, WhereTemplateNameMatches, index, is_default_sorted
 
-DeltaSizeInfo: ClassifySections, after, before, native_symbols, pak_symbols, raw_symbols, section_sizes, symbols
+DeltaSizeInfo: ClassifySections, after, before, build_config, native_symbols, pak_symbols, raw_symbols, section_sizes, symbols
 DeltaSymbol (extends Symbol): after_symbol, before_symbol, diff_status
 DeltaSymbolGroup (extends SymbolGroup): CountsByDiffStatus, WhereDiffStatusIs, diff_status
 
diff --git a/tools/binary_size/libsupersize/testdata/Diff_Basic.golden b/tools/binary_size/libsupersize/testdata/Diff_Basic.golden
index f7a9e058226837..216bd9713fa6ef 100644
--- a/tools/binary_size/libsupersize/testdata/Diff_Basic.golden
+++ b/tools/binary_size/libsupersize/testdata/Diff_Basic.golden
@@ -1,10 +1,15 @@
 Common Metadata:
     baz=yes
     foo=1
+    gn_args=var1=true var2="foo"
+    linker_name=gold
+    tool_prefix=tools/binary_size/libsupersize/testdata/mock_toolchain/
 Old Metadata:
     bar=[1, 2, 3]
+    git_revision=abc123
 New Metadata:
     bar=[1, 3]
+    git_revision=xyz789
 
 Section Sizes (Total=0 bytes (0 bytes)):
     .bss: 0 bytes (0 bytes) (not included in totals)