Add unwind information to mips epilogues

[Richard Sandiford]

Bernd Schmidt <bernds@codesourcery.com> writes:
> On 08/31/11 20:43, Richard Sandiford wrote:
>> Bernd Schmidt <bernds@codesourcery.com> writes:
>>> This is necessary when adding shrink-wrapping; otherwise dwarf2cfi sees
>>> inconsistent information and aborts.
>>>
>>> Tested on mips64-elf together with the rest of the shrink-wrapping
>>> patches. Ok?
>> 
>> It looks like the current code doesn't handle the RESTORE instruction.
>> Could you also test that somehow?  A mipsisa32-elf run with -mips16
>> ought to work
>
> Hmm, I'm having some trouble with that.
>  * mipsisa32-elf doesn't build on trunk
>  * 4.6 doesn't allow plain "-mips16"; I have to add "-msoft-float"
>  * With that, 4.6 produces rather a lot of testsuite failures.
>    (>400 execute failures in my current run and it's not even gotten
>    very far)
>
> Just to make sure - am I missing anything here, or is this stuff just in
> bad shape?

Gah, my bad, sorry.  I'd forgotten mipsisa32-elf is EABI32
rather than o32.  mips-elf with -mips32/-mips16 would test
what I was after.  Or the kind of spot-checks I was thinking
of could be done with any mips* compiler.  Compile some tests
that are interesting for shrinking wrapping with:

    -c -mips16 -mips32 -mabi=32 -Owhatever

and see if (a) it compiles, (b) it uses shrink-wrap and RESTORE
and (c) the CFI dump (from readelf -wf or whatever) looks OK.

Thanks for trying though.  I'll look into the mipsisa32-elf build failure
and (if I get time) the EABI32 -mips16/-msoft-float problem.

(For the record, I do test -mips16 fairly regularly, but at a lower
ISA level.  I suppose I should try MIPS16e more myself too....)

Richard