Subzero: Add a script that builds a hybrid Subzero/llc native executable.

Subzero: Add a script that builds a hybrid Subzero/llc native executable.

The script translates a pexe using both Subzero and llc, and then uses linker tricks to resolve each symbol into either its Subzero or llc version.  This enables quick bisection-based debugging of Subzero code generation.

BUG= none
R=jfb@chromium.org, jvoung@chromium.org

Committed: https://gerrit.chromium.org/gerrit/gitweb?p=native_client/pnacl-subzero.git;a=commit;h=10ea698

[Jim Stichnoth, 2014-09-08 19:06:42]

stichnot@chromium.org changed reviewers:
+ dschuff@chromium.org, jfb@chromium.org, jvoung@chromium.org,
kschimpf@google.com

[JF, 2014-09-08 23:14:16]

https://codereview.chromium.org/551953002/diff/20001/pydir/szbuild.py
File pydir/szbuild.py (right):

https://codereview.chromium.org/551953002/diff/20001/pydir/szbuild.py#newcode88
pydir/szbuild.py:88: """
Change the code to:

def main():
  """awesome-o docstring..."""
  # ...
  argparser.ArgumentParser(description=__doc__)
  # ...


if __name__ == '__main__':
  main()

https://codereview.chromium.org/551953002/diff/20001/pydir/szbuild.py#newcode115
pydir/szbuild.py:115: pexe_base = re.sub('\.pexe', '', pexe)
os.path.{basename,splitext}

[Jim Stichnoth, 2014-09-09 00:56:20]

https://codereview.chromium.org/551953002/diff/20001/pydir/szbuild.py
File pydir/szbuild.py (right):

https://codereview.chromium.org/551953002/diff/20001/pydir/szbuild.py#newcode88
pydir/szbuild.py:88: """
On 2014/09/08 23:14:16, JF wrote:
> Change the code to:
> 
> def main():
>   """awesome-o docstring..."""
>   # ...
>   argparser.ArgumentParser(description=__doc__)
>   # ...
> 
> 
> if __name__ == '__main__':
>   main()

Done.

https://codereview.chromium.org/551953002/diff/20001/pydir/szbuild.py#newcode115
pydir/szbuild.py:115: pexe_base = re.sub('\.pexe', '', pexe)
On 2014/09/08 23:14:16, JF wrote:
> os.path.{basename,splitext}

Done.

[JF, 2014-09-09 01:22:25]

shellcmd is mildly icky, but I'll let other pythonistas quibble over it and call
it lgtm.

[jvoung (off chromium), 2014-09-09 17:28:58]

LGTM too

https://codereview.chromium.org/551953002/diff/40001/pydir/szbuild.py
File pydir/szbuild.py (right):

https://codereview.chromium.org/551953002/diff/40001/pydir/szbuild.py#newcode13
pydir/szbuild.py:13: """Creates a regex string from an array of patterns and an
array
nit: Usually docstrings are:

1 line summary.
<blank line>
Rest of the documentation.

https://codereview.chromium.org/551953002/diff/40001/pydir/szbuild.py#newcode173
pydir/szbuild.py:173: ).format(sym=sym_llc, obj=obj_llc))
Is this still necessary, with the -externalize options?

https://codereview.chromium.org/551953002/diff/40001/pydir/szbuild.py#newcode219
pydir/szbuild.py:219: '{{unsandboxed_irt,irt_query_list}}.o ' +
Maybe note that this set of files to link is to be kept in sync with
pnacl-translate's "RunHostLD"? Only difference seems to be the addition of
szrt.c.

https://codereview.chromium.org/551953002/diff/40001/pydir/szbuild.py#newcode224
pydir/szbuild.py:224: if args.verbose:
If useful, you could also have shellcmd(..., echo=args.verbose)

[Jim Stichnoth, 2014-09-09 18:14:16]

https://codereview.chromium.org/551953002/diff/40001/pydir/szbuild.py
File pydir/szbuild.py (right):

https://codereview.chromium.org/551953002/diff/40001/pydir/szbuild.py#newcode13
pydir/szbuild.py:13: """Creates a regex string from an array of patterns and an
array
On 2014/09/09 17:28:58, jvoung wrote:
> nit: Usually docstrings are:
> 
> 1 line summary.
> <blank line>
> Rest of the documentation.

Done.

https://codereview.chromium.org/551953002/diff/40001/pydir/szbuild.py#newcode173
pydir/szbuild.py:173: ).format(sym=sym_llc, obj=obj_llc))
On 2014/09/09 17:28:58, jvoung wrote:
> Is this still necessary, with the -externalize options?

Interesting, I think you're right.  It looks like with -externalize, the only
local symbols are the Subzero FP constant pool entries, which should probably
remain local in any case.

https://codereview.chromium.org/551953002/diff/40001/pydir/szbuild.py#newcode219
pydir/szbuild.py:219: '{{unsandboxed_irt,irt_query_list}}.o ' +
On 2014/09/09 17:28:58, jvoung wrote:
> Maybe note that this set of files to link is to be kept in sync with
> pnacl-translate's "RunHostLD"? Only difference seems to be the addition of
> szrt.c.

Done.

https://codereview.chromium.org/551953002/diff/40001/pydir/szbuild.py#newcode224
pydir/szbuild.py:224: if args.verbose:
On 2014/09/09 17:28:58, jvoung wrote:
> If useful, you could also have shellcmd(..., echo=args.verbose)

Good idea.  It probably shouldn't be so chatty by default.

[Jim Stichnoth, 2014-09-09 18:19:18]

Committed patchset #4 (id:60001) manually as 10ea698 (presubmit successful).