nested function question

[Ian Lance Taylor]

On Tue, Sep 11, 2012 at 2:15 AM, Aurelien Buhrig
<aurelien.buhrig.gcc@gmail.com> wrote:
>
>
>
>> Hi,
>>
>> The gcc.c-torture/execute/nestfunc-3.c test fails on a private target. I
>> suspect this is because the STATIC_CHAIN_REGNUM, which is not a call
>> used register, is used by the caller function (main), modified by the
>> trampoline, but not restored upon nested function return.
>>
>> Should the STATIC_CHAIN_REGNUM be defined so that
>> CALL_USED_REGISTERS[STATIC_CHAIN_REGNUM] == 0?
>
> The question is rather:
> Should the STATIC_CHAIN_REGNUM be defined so that
> CALL_USED_REGISTERS[STATIC_CHAIN_REGNUM] == 1? Or is it possible to make
> nested functions work if CALL_USED_REGISTERS[STATIC_CHAIN_REGNUM] == 0?

The static chain register is normally a call-used register or a fixed
register or a stack location.  It may be possible to make it work with
a call-saved register, but clearly it is essential that the call to
the nested function restore the original value of the register before
returning.

Ian