llvm dev - Sep 2015 - [libunwind][Mips] Problem using gas to assemble UnwindRegistersSave.S

The latest TOT of libunwind fails for me when I build 
UnwindRegistersSave.S for the Mips. My copy of clang uses a 2.25 
binutils Mips assembler.
This is the message I get:

  "/home/rich/ellcc/bin/mips-elf-as" -o 
/tmp/UnwindRegistersSave-a2c974.o -EL /tmp/UnwindRegistersSave-545450.s
src/UnwindRegistersSave.S: Assembler messages:
src/UnwindRegistersSave.S:99: Error: opcode not supported on this 
processor: mips1 (mips1) `teq $0,$0'

If I compile with -integrated-as it assembles as expected.

I was able to get it to work without the integrated assembler with this 
change:



#
# extern int unw_getcontext(unw_context_t* thread_state)
#
# Just trap for the time being.
DEFINE_LIBUNWIND_FUNCTION(unw_getcontext)
   .set mips32r2
   teq $0, $0

#elif defined(__ppc__)

telling the assembler to allow r2 instructions.

Should the integrated assembler be enabled by default for the Mips? It 
looks as if the stock clang does not use the integrated assembler yet.

-Rich

Hi Richard,

Clang doesn't have support for MIPS I. The trap-on-condition instructions
were added in MIPS II and they should work fine. This is why it works with
".set mips32r2".

Which version of the ISA did you specify when you used the integrated assembler?

Thanks,
Vasileios

On 09/27/2015 06:41 PM, Vasileios Kalintiris wrote:
> Hi Richard,
>
> Clang doesn't have support for MIPS I. The trap-on-condition
instructions were added in MIPS II and they should work fine. This is why it
works with ".set mips32r2".
>
> Which version of the ISA did you specify when you used the integrated
assembler?
>
> Thanks,
> Vasileios
>
>
Hi Vasileios,

The integrated assembler works great. It was gas that complained. 
Apparently gas must default to MIPS I

-Rich