binary_size: Check debug data format before starting.

If the debug data format is DWARF4 and binutils is not new enough
the output will be more or less useless (no files will be detected).
Detect that case early instead of having the user wait for many hours
for something that can't be used.

BUG=370378

Review URL: https://codereview.chromium.org/302633003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@275866 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 32 insertions, 1 deletions

diff --git a/tools/binary_size/run_binary_size_analysis.py b/tools/binary_size/run_binary_size_analysis.py
index 4168874..aefc85d 100755
--- a/tools/binary_size/run_binary_size_analysis.py
+++ b/tools/binary_size/run_binary_size_analysis.py
@@ -561,6 +561,35 @@ def _find_in_system_path(binary):
       return binary_path
   return None
 
+def CheckDebugFormatSupport(library, addr2line_binary):
+  """Kills the program if debug data is in an unsupported format.
+
+  There are two common versions of the DWARF debug formats and
+  since we are right now transitioning from DWARF2 to newer formats,
+  it's possible to have a mix of tools that are not compatible. Detect
+  that and abort rather than produce meaningless output."""
+  tool_output = subprocess.check_output([addr2line_binary, '--version'])
+  version_re = re.compile(r'^GNU [^ ]+ .* (\d+).(\d+).*?$', re.M)
+  parsed_output = version_re.match(tool_output)
+  major = int(parsed_output.group(1))
+  minor = int(parsed_output.group(2))
+  supports_dwarf4 = major > 2 or major == 2 and minor > 22
+
+  if supports_dwarf4:
+    return
+
+  print('Checking version of debug information in %s.' % library)
+  debug_info = subprocess.check_output(['readelf', '--debug-dump=info',
+                                       '--dwarf-depth=1', library])
+  dwarf_version_re = re.compile(r'^\s+Version:\s+(\d+)$', re.M)
+  parsed_dwarf_format_output = dwarf_version_re.search(debug_info)
+  version = int(parsed_dwarf_format_output.group(1))
+  if version > 2:
+    print('The supplied tools only support DWARF2 debug data but the binary\n' +
+          'uses DWARF%d. Update the tools or compile the binary\n' % version +
+          'with -gdwarf-2.')
+    sys.exit(1)
+
 
 def main():
   usage = """%prog [options]
@@ -655,8 +684,10 @@ def main():
     assert nm_binary, 'Unable to find nm in the path. Use --nm-binary '\
         'to specify location.'
 
-  print('nm: %s' % nm_binary)
   print('addr2line: %s' % addr2line_binary)
+  print('nm: %s' % nm_binary)
+
+  CheckDebugFormatSupport(opts.library, addr2line_binary)
 
   symbols = GetNmSymbols(opts.nm_in, opts.nm_out, opts.library,
                          opts.jobs, opts.verbose is True,