On Fri, Nov 8, 2013 at 11:03 AM, Ilya Enkovich <enkovich....@gmail.com> wrote:
> 2013/11/8 Richard Biener <richard.guent...@gmail.com>:
>> On Thu, Nov 7, 2013 at 7:55 PM, Jeff Law <l...@redhat.com> wrote:
>>> On 11/07/13 04:50, Ilya Enkovich wrote:
>>>>
>>>> Hi,
>>>>
>>>> Here is an updated patch version.
>>>
>>> I think this needs to hold until we have a consensus on what the parameter
>>> passing looks like for bounded pointers.
>>
>> I still think the best thing to do on GIMPLE is
>>
>> arg_2 = __builtin_ia32_bnd_arg (arg_1(D));
>> foo (arg_2);
>>
>> that is, make the parameter an implicit pair of {value, bound} where
>> the bound is determined by the value going through a bound association
>> builtin. No extra explicit argument to the calls so arguments match
>> the fndecl and fntype. All the complexity is defered to the expander
>> which can trivially lookup bound arguments via the SSA def (I suppose
>> it does that anyway now for getting at the explicit bound argument now).
>>
>> As far as I can see (well, think), all currently passed bound arguments
>> are the return value of such builtin already.
>
> All bounds are result of different builtin calls. Small example:
>
> int *global_p;
> void foo (int *p)
> {
> int buf[10];
> bar (p, buf, global_p);
> }
>
>
> It is translated into:
>
> __bound_tmp.1_7 = __builtin_ia32_bndmk (&buf, 40);
> __bound_tmp.1_6 = __builtin_ia32_arg_bnd (p_3(D)(ab));
> global_p.0_2 = global_p;
> __bound_tmp.1_8 = __builtin_ia32_bndldx (&global_p, global_p.0_2);
> bar (p_3(D)(ab), __bound_tmp.1_6, &buf, __bound_tmp.1_7,
> global_p.0_2, __bound_tmp.1_8);
>
> Bounds binding via calls as you suggest may be done as following:
>
> __bound_tmp.1_7 = __builtin_ia32_bndmk (&buf, 40);
> __bound_tmp.1_6 = __builtin_ia32_arg_bnd (p_3(D)(ab));
> global_p.0_2 = global_p;
> __bound_tmp.1_8 = __builtin_ia32_bndldx (&global_p, global_p.0_2);
> _9 = __builtin_bind_bounds (p_3(D)(ab), __bound_tmp.1_6);
> _10 = __builtin_bind_bounds (&buf, __bound_tmp.1_7);
> _11 = __builtin_bind_bounds (global_p.0_2, __bound_tmp.1_8);
> bar (_9, _10, _11);
>
> Is it close to what you propose?
Yes.
Richard.
> Ilya
>>
>> Richard.
>>
>>
>>
>>> Jeff
