2012/11/28 Richard Henderson <r...@redhat.com>:
> On 11/25/2012 07:26 AM, Kai Tietz wrote:
>> - if ((ccvt & (IX86_CALLCVT_FASTCALL | IX86_CALLCVT_THISCALL)) != 0)
>> + if ((ccvt & IX86_CALLCVT_FASTCALL) != 0)
>> {
>> /* Fastcall functions use ecx/edx for arguments, which leaves
>> us with EAX for the static chain.
>> @@ -25142,6 +25160,12 @@ ix86_static_chain (const_tree fndecl, bo
>> leaves us with EAX for the static chain. */
>> regno = AX_REG;
>> }
>> + else if ((ccvt & IX86_CALLCVT_THISCALL) != 0)
>> + {
>> + /* Thiscall functions use ecx for arguments, which leaves
>> + us with EDX for the static chain. */
>> + regno = DX_REG;
>> + }
>
> How is this not abi breakage? Why not leave eax as the static chain?
>
>
> r~
Well, interesting function here is get_scratch_register_on_entry,
where for thiscall (it uses just ecx) we have by this %eax remaining
as scratch. Well, we could switch that here and make scratch %edx for
thiscall?
Kai
