Specify architecture for SPARC gas tests

[Jose E. Marchesi]

Hi Rainer.  Thanks for looking at this.

    A couple of SPARC gas tests FAIL on Solaris/SPARC (both
    sparc-sun-solaris2.11 and sparcv9-sun-solaris2.11):
    
    FAIL: sparc PAUSE
    FAIL: sparc CBCOND
    FAIL: sparc CFR
    FAIL: sparc CRYPTO
    FAIL: sparc HPC+VIS3
    FAIL: sparc IMA
    FAIL: sparc OSA2015 %mwait asr and MWAIT instruction
    FAIL: sparc OSA2015 %mcdper asr
    FAIL: sparc SPARC5 and VIS4.0
    FAIL: OSA2015 crypto instructions
    FAIL: SPARC6
    FAIL: FPCMPSHL OSA2017 instructions
    FAIL: OSA2017 ONADD/ONSUB/ONMUL/ONDIV instructions.
    FAIL: OSA2017 RLE instructions
    FAIL: sparc64 rdasr
    FAIL: sparc64 rdpr
    FAIL: sparc64 rdhpr
    FAIL: sparc64 wrasr
    FAIL: sparc64 wrpr
    
    It turns out there's a common pattern here: failures happen for all
    tests that use SPARC ISA extensions beyond sparcv9, e.g. for the sparc
    PAUSE test:
    
    regexp_diff match failure
    regexp "^   0:  b7 80 40 02     wr  %g1, %g2, %pause$"
    line   "   0:   b7 80 40 02     wr  %g1, %g2, %asr27"
    [...]
    regexp_diff match failure
    regexp "^   8:  b7 80 20 08     pause  8$"
    line   "   8:   b7 80 20 08     wr  8, %asr27"
    [...]
    
    The fix is easy, actually: just as the tests specify the ISA extension
    to use as a gas flag, the same needs to be done for objdump.  For the
    test above, which has -Av9v, this means passing -msparc:v9v to objdump.
    Doing so makes all but two (unrelated; to be reported separately)
    failures go away.

In GNU/Linux GAS annotates the hardware capabilities when it assembles
an ELF object.  From gas/config/tc-sparc.c:sparc_md_end:

#if defined(OBJ_ELF) && !defined(TE_SOLARIS)
  hwcaps = hwcap_seen & U0xffffffff;
  hwcaps2 = hwcap_seen >> 32;

  if (hwcaps)
    bfd_elf_add_obj_attr_int (stdoutput, OBJ_ATTR_GNU, Tag_GNU_Sparc_HWCAPS, hwcaps);
  if (hwcaps2)
    bfd_elf_add_obj_attr_int (stdoutput, OBJ_ATTR_GNU, Tag_GNU_Sparc_HWCAPS2, hwcaps2);
#endif

Then when BFD opens the file, it looks at the GNU object attributes
HWCAPS and HWCAPS2 and determines the opcodes architecture that is
subsequently used by the disassembler.  See
bfd/elfxx-spac.c:_bfd_sparc_elf_object_p.

The hwcaps tags are not created in Solaris though, so that's why the
tests are failing...  I wonder if it is possible to change the tests so
they use -msparc:MACH only when testing in solaris targets?

Alternatively, I guess we could just change the assembler to add the GNU
object attributes also in solaris...