Re: [PATCH] Ensure that MIPS target code is compiled for the O32 ABI.

[Andrei Borzenkov <arvidjaar@gmail.com>]

22.08.2015 21:04, Mark H Weaver пишет:
> Andrei Borzenkov <arvidjaar@gmail.com> writes:
>
>> 19.08.2015 21:35, Mark H Weaver пишет:
>>> Include -mabi=32 in CFLAGS_PLATFORM and CCASFLAGS_PLATFORM to compile
>>> code for the O32 ABI when targetting MIPS, since the MIPS assembly code
>>> in GRUB assumes this.  This flag is also needed when compiling
>>> asm-tests/mips.S from configure, because GNU as rejects MIPS register
>>> names such as $t2 unless the O32 ABI is selected.
>>> ---
>>>    conf/Makefile.common | 4 ++++
>>>    configure.ac         | 7 +++++--
>>>    2 files changed, 9 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/conf/Makefile.common b/conf/Makefile.common
>>> index fcb8d2e..bd125da 100644
>>> --- a/conf/Makefile.common
>>> +++ b/conf/Makefile.common
>>> @@ -20,6 +20,10 @@ endif
>>>    if COND_powerpc_ieee1275
>>>      CFLAGS_PLATFORM += -mcpu=powerpc
>>>    endif
>>> +if COND_mips
>>> +  CFLAGS_PLATFORM += -mabi=32
>>> +  CCASFLAGS_PLATFORM = -mabi=32
>>> +endif
>>>
>>
>> Does it work with clang?
>
> Based on the error message below, clang seems to accept and understand
> the -mabi=32 option, but the version of clang that we have in GNU Guix
> (which uses the N32 ABI on MIPS) seems to lack support for compiling for
> O32:
>
>    mhw@librenote:~$ clang -mabi=32 mips.S
>    error: unknown target CPU 'mips32r2'
>
> However, it doesn't work without that option either:
>
>    mhw@librenote:~$ clang mips.S
>    mips.S: Assembler messages:
>    mips.S:7: Error: invalid operands `ld $t2,0($t6)'
>    mips.S:10: Error: invalid operands `addiu $t7,$s0,(b-a)'
>    clang-3.6: error: assembler command failed with exit code 1 (use -v to see invocation)
>
> This is the same failure that occurs with gcc when configured to use the
> N32 ABI by default.  I also tried passing -fno-integrated-as in both
> cases above, but it made no difference.
>

Could you paste "clang -v" output for both cases? I believe I understand 
what's going on.