[LLVMdev] llc with -march=mips failed to compile va_start()/va_end()/va_arg()

[Akira Hatanaka]

You might want to use clang instead of llvm-gcc: I think there are
still bugs that remain unfixed in llvm-gcc and it is unlikely that
someone will fix them.

clang -ccc-host-triple mipsel-unknown-linux -ccc-clang-archs mipsel
-emit-llvm -O3 -S -o hello.ll hello.c
llc  hello.ll -o hello.s

On Mon, Aug 15, 2011 at 10:52 AM, Jim Grosbach <grosbach at apple.com> wrote:
>
> On Aug 15, 2011, at 9:42 AM, Eli Friedman wrote:
>
>> On Mon, Aug 15, 2011 at 2:18 AM, Leo Chen. <leo.q.chen at gmail.com> wrote:
>>> Hi,
>>>
>>> I am using llc (llvm 2.9) to generate the MIPS assembly
>>
>> I would suggest trying trunk; there have been a lot of improvements
>> recently to the MIPS backend.
>>
>
> I agree. Also, make sure you're using a MIPS targeted llvm-gcc build. It's unclear from your usage example how llvm-gcc was configured. You can't reliably use an x86 llvm-gcc to generate bitcode and pass that to llc targeting a difference arch.
>
> -Jim
>
>> -Eli
>>
>>> but failed
>>> when compile any codes
>>> with va_start()/va_end()/va_arg().
>>>
>>> Here is the minimal step to reproduce the failure:
>>> llvm-gcc-4.2 -emit-llvm hello.c -c -o hello.bc
>>> llc -march=mips hello.bc -o hello.s
>>>
>>> llc show this erroe message:
>>> LLVM ERROR: Cannot select: 0xa1873a0: ch = vaend 0xa187290:1,
>>> 0xa185ae0, 0xa187318 [ID=38]
>>>  0xa185ae0: i32 = FrameIndex<1> [ORD=3] [ID=10]
>>>
>>> I try the same thing on arch x86/ARM like this, and they just work fine:
>>> llc hello.bc -o hello.s  //x86
>>> llc -march=arm hello.bc -o hello.s  //ARM
>>>
>>> Can anyone tell me whether it's a bug so that I could submit the bug
>>> on Bugzilla?
>>> And any suggestion about how to fix this problem is appreciated.
>>>
>>> ----------- hello.c --------------------------
>>> #include <stdio.h>
>>> #include <stdarg.h>
>>> void print_msg( const char *fmt, ... )
>>> {
>>>    va_list ap;
>>>    va_start( ap, fmt );
>>>    vprintf( fmt, ap );
>>>    va_end( ap );
>>> }
>>> int main()
>>> {
>>>    print_msg( "hello\n" );
>>>    return 0;
>>> }
>>> -----------------------------------------------
>>>
>>>
>>> Regards,
>>> Leo
>>> _______________________________________________
>>> LLVM Developers mailing list
>>> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
>>> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>>>
>>
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