[PowerPC, Mach-O] PPCMachObjectWriter.cpp, at long last

[David Fang]

Don,
 	The test doesn't actually *run* the executable, it only produces 
the object file and compares the output, doesn't even link to an 
executable.  The cpu/triple needs to be specified so !powerpc-darwin users 
see the same result, just cross-compiled.

Fang

> Question: Should the mcpu and mtriple flags somehow be detected?
>
> I ask because if I run this on my G5, would it not fail?
>
> Don
>
> On 7/25/13 11:27 AM, David Fang wrote:
>>  Rafael,
>>
>>  Testing .s->.o via llvm-mc would be ideal, but the PPCAsmParser doesn't
>>  support darwin syntax yet.
>>  I've revised the test commands and added a comment:
>>
>>  [hello-reloc.ll]
>>  ...
>> ;  RUN: llc -filetype=asm -relocation-model=pic -mcpu=g4
>>  -mtriple=powerpc-apple-darwin8 %s -o - | tee %t1 | FileCheck
>>  -check-prefix=DARWIN-G4-ASM %s
>> ;  RUN: llc -filetype=obj -relocation-model=pic -mcpu=g4
>>  -mtriple=powerpc-apple-darwin8 %s -o - | tee %t2 | macho-dump | tee %t3
>>  FileCheck -check-prefix=DARWIN-G4-DUMP %s
>> 
>> ;  FIXME: validating .s->.o requires darwin asm syntax support in
>>  PPCAsmParser
>> ;  RUN-XFAIL: llvm-mc -relocation-model=pic -mcpu=g4
>>  -triple=powerpc-apple-darwin8 %t1 -o - | tee %t4 | macho-dump | tee %t5 |
>>  FileCheck -check-prefix=DARWIN-G4-DUMP %s
>> ;  RUN-XFAIL: diff -u %t2 %t4 || diff -u %t3 %t5
>>
>>  The RUN-XFAIL doesn't actually run, it's just a comment.
>>  The diff first compares object files, and if that fails, the second diff
>>  will also fail and show the differences from macho-dump.
>>
>>  Would this be acceptable for now?
>>
>>  Fang
>> 
>> >  OK, now that I see that this is adding the entire PPCMachObjectWriter
>> >  I think it should be tested with llvm-mc. Even a hack like using a .s
>> >  file with "linux" syntax would be better than depending on llc
>> >  -filetype=obj.
>> > 
>> >  In the past uses llc -filetype=obj stayed around longer than intended
>> >  and were fairly brittle.
>> > 
>> >  On 25 July 2013 00:05, David Fang <fang at csl.cornell.edu> wrote:
>> > >  Hi,
>> > >          Attached is a patch from my powerpc-darwin8 branch
>> > >  [https://github.com/fangism/llvm/tree/powerpc-darwin8] that I've been
>> > >  maintaining and merging from trunk for months.  This contains the 
>> > >  first cut
>> > >  of the relocation entry implementation for mach-o/PPC, which is 
>> > >  missing on
>> > >  trunk.
>> > > 
>> > >  The patch addresses the feature requested here:
>> > >  http://llvm.org/bugs/show_bug.cgi?id=14636
>> > > 
>> > >  1. This patch was extracted piecewise from my powerpc-darwin8 branch. 
>> > >  I can
>> > >  only compile the branch and not master/trunk because of other
>> > >  compiler-workarounds that are needed, but excluded from this patch.
>> > >  It's *possible* I may have made a cut/paste/merge error.
>> > >  I could use a volunteer or two to actually test-compile and run this 
>> > >  on
>> > >  svn-trunk.  Running the new test CodeGen/PowerPC/hello-reloc.ll with
>> > >  llvm-lit would be great feedback, and shouldn't require a Darwin 
>> > >  machine,
>> > >  just have Targets=PPC.
>> > > 
>> > >  2. I've tested PIC objects on small hello-world sized programs such as 
>> > >  the
>> > >  test that is included.  The executables run correctly.
>> > > 
>> > >  3. I have compared the object files and their dumps against 
>> > >  system-assembled
>> > >  (GNU as) object files.  (See bug report above for details.)
>> > > 
>> > >  4. Style comments are welcome, though effort to conform on this was 
>> > >  minimal.
>> > >  I plan to follow through on feedback.
>> > > 
>> > >  I understand this may take many iterations, but the ball has to get 
>> > >  rolling
>> > >  some time.
>> > > 
>> > >  Let the comments begin.
>> > > 
>> > >  Fang
>> > > 
>> > >  -- 
>> > >  David Fang
>> > >  http://www.csl.cornell.edu/~fang/
>> > > 
>>>> _______________________________________________
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>> > >  llvm-commits at cs.uiuc.edu
>> > >  http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
>> > > 
>> > 
>> 
>
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-- 
David Fang
http://www.csl.cornell.edu/~fang/