Re: [PATCH v4 03/36] tcg: Allocate objects contiguously in temp_allocate_frame

[Richard Henderson]

On 1/11/23 01:59, Alex Bennée wrote:
> > @@ -3277,13 +3278,26 @@ static void temp_allocate_frame(TCGContext *s, TCGTemp 
> > *ts)
> >           tcg_raise_tb_overflow(s);
> >       }
> >       s->current_frame_offset = off + size;
> > -
> > -    ts->mem_offset = off;
> >   #if defined(__sparc__)
> > -    ts->mem_offset += TCG_TARGET_STACK_BIAS;
> > +    off += TCG_TARGET_STACK_BIAS;
> >   #endif
> > -    ts->mem_base = s->frame_temp;
> > -    ts->mem_allocated = 1;
> > +
> > +    /* If the object was subdivided, assign memory to all the parts. */
> > +    if (ts->base_type != ts->type) {
> > +        int part_size = tcg_type_size(ts->type);
> > +        int part_count = size / part_size;
> > +
> > +        ts -= ts->temp_subindex;
>
> Whats going on here? Are we jumping to a previous temp? What guarentees
> there is something at ts - ts->temp_subindex?

Yes.  Guaranteed by base_type != type.  See tcg_temp_new_internal -- it's the raison 
d'être of temp_subindex.


r~