supersize: Tweak diff symbol matching for generated symbols

tools/binary_size/libsupersize/integration_test.py

 #!/usr/bin/env python
 # 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.
 
 import contextlib
 import copy
 import difflib
 import glob
 import itertools
@@ skipping 218 matching lines @@
     size_info2.symbols -= [a1, a2, a3]
     d = diff.Diff(size_info1, size_info2)
     self.assertEquals(d.symbols.size, -a1.size)
     self.assertEquals(d.symbols.removed_count, 3)
 
     # Adding all 3 aliases should change size.
     d = diff.Diff(size_info2, size_info1)
     self.assertEquals(d.symbols.size, a1.size)
     self.assertEquals(d.symbols.added_count, 3)
 
+  def test_Diff_Clustering(self):
+    size_info1 = self._CloneSizeInfo()
+    size_info2 = self._CloneSizeInfo()
+    S = '.text'
+    size_info1.symbols += [
+        models.Symbol(S, 11, name='.L__unnamed_1193', object_path='a'), # 1
+        models.Symbol(S, 22, name='.L__unnamed_1194', object_path='a'), # 2
+        models.Symbol(S, 33, name='.L__unnamed_1195', object_path='b'), # 3
+        models.Symbol(S, 44, name='.L__bar_195', object_path='b'), # 4
+        models.Symbol(S, 55, name='.L__bar_1195', object_path='b'), # 5
+    ]
+    size_info2.symbols += [
+        models.Symbol(S, 33, name='.L__unnamed_2195', object_path='b'), # 3
+        models.Symbol(S, 11, name='.L__unnamed_2194', object_path='a'), # 1
+        models.Symbol(S, 22, name='.L__unnamed_2193', object_path='a'), # 2
+        models.Symbol(S, 44, name='.L__bar_2195', object_path='b'), # 4
+        models.Symbol(S, 55, name='.L__bar_295', object_path='b'), # 5
+    ]
+    d = diff.Diff(size_info1, size_info2)
+    self.assertEquals(d.symbols.added_count, 0)
+    self.assertEquals(d.symbols.size, 0)
+
+
   @_CompareWithGolden()
   def test_FullDescription(self):
     return describe.GenerateLines(self._CloneSizeInfo().Cluster(),
                                   recursive=True, verbose=True)
 
   @_CompareWithGolden()
   def test_SymbolGroupMethods(self):
     all_syms = self._CloneSizeInfo().symbols
     global_syms = all_syms.WhereNameMatches('GLOBAL')
     # Tests Filter(), Inverted(), and __sub__().
@@ skipping 23 matching lines @@
     global update_goldens
     update_goldens = True
     for f in glob.glob(os.path.join(_TEST_DATA_DIR, '*.golden')):
       os.unlink(f)
 
   unittest.main(argv=argv, verbosity=2)
 
 
 if __name__ == '__main__':
   main()