Simplify check_tls on ARM, now that llvm emits mapping symbols.

src/untrusted/irt/check_tls.py

 # Copyright (c) 2012 The Native Client Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # A simple program to run objdump on a file and assert that the ABI TLS
 # register appears nowhere in it.  This ensures that the direct register access
 # style of TLS is not being used in the IRT blob.
 
 import subprocess
 import sys
@@ skipping 13 matching lines @@
   whitelist_regex = None
   if arch == 'x86-32':
     objdump_args = [objdump, '-d', obj_file]
     # "%gs:4" is allowed but all other uses of %gs are suspect.
     register = '%gs'
     regex = re.compile(register + r'(?!:0x4\b)')
   elif arch == 'x86-64':
     # Nothing to check.
     regex = None
   elif arch.startswith('arm'):
-    if arch == 'arm-gcc':
-      objdump_flags = ['-d']
-    elif arch == 'arm-pnacl':
-      # TODO(mcgrathr): Just use -d when PNaCl compiler is fixed so it works.
-      # See http://code.google.com/p/nativeclient/issues/detail?id=2818
-      objdump_flags = ['-D', '--section=.text']
+    objdump_flags = ['-d']
     objdump_args = [objdump] + objdump_flags + [obj_file]
     # A real reference to r9 should probably be preceded by some character
     # that is not legal for an identifier (e.g., spaces, commas, brackets).
     register = 'r9'
     regex = re.compile('[^_\w]' + register)
     whitelist_regex = re.compile(r'ldr\s+r0,\s*\[r9,\s*#4\]\s*$')
   else:
     print 'Unknown architecture: %s' % arch
     sys.exit(1)
 
   if regex is not None:
     proc = subprocess.Popen(objdump_args,

[Roland McGrath, 2013/03/04 23:15:41]

objdump_flags and objdump_args are now set unconditionally.
So just set objdump_args unconditionally at the top before the if chain.

[jvoung (off chromium), 2013/03/05 00:34:40]

Done.

                             stdout=subprocess.PIPE,
                             bufsize=-1)
     for line in proc.stdout:
       if regex.search(line) and not (whitelist_regex is not None and
                                      whitelist_regex.search(line)):
         print '%s use found: %s' % (register, line)
         print 'This looks like an %s direct TLS use.' % arch
         print 'Such uses are disallowed by the IRT context constraints.'
         print 'These never happen if -mtls-use-call is used in the compilation.'
         print 'Check that all libraries used in the IRT were compiled that way.'
         sys.exit(1)
     if proc.wait() != 0:
       print 'Command failed: %s' % objdump_args
       sys.exit(1)
 
   if outfile is not None:
     outf = open(outfile, 'w')
     outf.write('TLS in %s OK\n' % obj_file)
     outf.close()
 
 
 if __name__ == '__main__':
   Main(sys.argv[1:])