Allow subzero tests to pass without le32-nacl-objdump.

pydir/run-pnacl-sz.py

 #!/usr/bin/env python2
 
 import argparse
 import itertools
 import os
 import re
 import subprocess
 import sys
 import tempfile
 
@@ skipping 178 matching lines @@
         asm_temp.close()
         output_file_name = asm_temp.name
     if args.assemble and args.filetype != 'obj':
       cmd += (['|', os.path.join(pnacl_bin_path, 'llvm-mc')] +
               TargetAssemblerFlags(args.target, args.sandbox) +
               ['-filetype=obj', '-o', output_file_name])
     elif output_file_name:
       cmd += ['-o', output_file_name]
     if args.disassemble:
       # Show wide instruction encodings, diassemble, and show relocs.
-      cmd += (['&&', os.path.join(pnacl_bin_path, 'le32-nacl-objdump')] +
+      cmd += (['&&', os.path.join(pnacl_bin_path, 'arm-nacl-objdump')] +

[Jim Stichnoth, 2016/03/09 14:38:04]

IIRC, originally the tests used the system objdump.  Later, we changed to
llvm-objdump, probably because different host systems might have different
versions of objdump with differences in output.  Sometime later, we switched to
le32-nacl-objdump because llvm-objdump was due to change its ability to
symbolize the output.

I guess "le32" was always a bit weird because there is no guarantee that the
host system or the generated code is le32, but calling out "arm" is even
weirder.

I tried changing this to i686 or x86_64, but it looks like those builds are
unaware of MIPS.

Could you maybe quarantine the weirdness by defining a helper function in this
file?  e.g.

  def GetObjdumpCmd():
    """Return a suitable objdump command."""
    return 'arm-nacl-objdump'

Later, if needed, this could be modified to construct the entire path and args
on a per-target basis, but for now I'm OK just returning a fixed string.

[Sean Klein, 2016/03/09 18:27:44]

Yeah, I agree that it's not very intuitive that "arm" happens to cover all
architectures we care about.

Updated to the "GetObjdumpCmd" function version.

               args.dis_flags +
               ['-w', '-d', '-r'] + TargetDisassemblerFlags(args.target) +
               [output_file_name])
 
     stdout_result = shellcmd(cmd, echo=args.echo_cmd)
     if not args.echo_cmd:
       sys.stdout.write(stdout_result)
     if asm_temp and not keep_output_file:
       os.remove(output_file_name)
 
 if __name__ == '__main__':
     main()