Re: [Qemu-devel] assertion in temp_save

[Max Filippov <jcmvbkbc@gmail.com>]

On Sun, Nov 18, 2012 at 7:34 AM, Max Filippov <jcmvbkbc@gmail.com> wrote:
> On Sun, Nov 18, 2012 at 7:19 AM, Max Filippov <jcmvbkbc@gmail.com> wrote:
>> Hi Aurelien,
>>
>> starting with commit 2c0366f tcg: don't explicitly save globals and temps
>> I get the following abort on target-xtensa:
>>
>> qemu-system-xtensa: tcg/tcg.c:1665: temp_save: Assertion
>> `s->temps[temp].val_type == 2 || s->temps[temp].fixed_reg' failed.
>> Aborted
>>
>> I see that that commit only adds assertion and that bad thing happens
>> elsewhere. I've found that removal of tcg_gen_discard_i32 in the
>> gen_right_shift_sar makes it work again. The trace of the TB that fails
>> translation is below. If 'discard loc5' is removed it starts to work.
>>
>> Any idea of what might be wrong?
>
> In the debugger loc5 looks like this when abort happens:
>
> (gdb) p s->temps[105]
> $2 = {
>   base_type = TCG_TYPE_I32,
>   type = TCG_TYPE_I32,
>   val_type = 0,
>   reg = 11,
>   val = 32,
>   mem_reg = 4,
>   mem_offset = 128,
>   fixed_reg = 0,
>   mem_coherent = 0,
>   mem_allocated = 0,
>   temp_local = 1,
>   temp_allocated = 0,
>   next_free_temp = -1,
>   name = 0x0
> }

Looks like the issue is local temp reaching the end of TB in a dead state.
Hence the question: is discard applicable to local temps?
Or maybe I should just make it global (two other tcg values used with discard
in other targets are also globals) and avoid temp_local_new/temp_free at
first place?

-- 
Thanks.
-- Max