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tools/binary_size/libsupersize/nm.py

Index: tools/binary_size/libsupersize/nm.py
diff --git a/tools/binary_size/libsupersize/nm.py b/tools/binary_size/libsupersize/nm.py
new file mode 100644
index 0000000000000000000000000000000000000000..c6811d6b8ff7ac4b6edf3529b81f9e5183022167
--- /dev/null
+++ b/tools/binary_size/libsupersize/nm.py
@@ -0,0 +1,37 @@
+# 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.
+
+"""Dealing with "nm" tool."""
+
+import collections
+import subprocess
+
+
+def CollectAliasesByAddress(elf_path, tool_prefix):
+  names_by_address = collections.defaultdict(list)
+
+  # About 60mb of output, but piping takes ~30s, and loading it into RAM
+  # directly takes 3s.
+  args = [tool_prefix + 'nm', '--no-sort', '--defined-only', '--demangle',
+          elf_path]
+  output = subprocess.check_output(args)
+  for line in output.splitlines():
+    address_str, section, name = line.split(' ', 2)
+    if section not in 'tT' or not name or name[0] == '$':
+      continue
+
+    address = int(address_str, 16) & 0xfffffffffffffffe
+    if not address:
+      continue
+    # Constructors often show up twice.
+    name_list = names_by_address[address]
+    if name not in name_list:
+      name_list.append(name)
+
+  # Since this is run in a separate process, minimize data passing by returning
+  # only aliased symbols.
+  names_by_address = {k: v for k, v in names_by_address.iteritems()
+                      if len(v) > 1}
+
+  return names_by_address