[pypy-dev] Virtualizable Frames getting half removed in trace

[Timothy Baldridge]

correction on my last email "but that list was never used"


On Tue, Feb 25, 2014 at 7:06 AM, Timothy Baldridge <tbaldridge at gmail.com>wrote:

> So I spent two more hours on this this morning and finally got some good
> results.
>
> a) I turned on _immutable_ = True on the Code object. Should have done
> this before.
>
> Then I noticed that the trace contained the creation of the argument list,
> but that that list was never made. The trace was also making a call out to
> some C function so that it could do the array = [None] * argc. I couldn't
> get that to go away even with promoting argc. So I changed pop_values to
> this instead:
>
> def pop_values(frame, argc):
>     if argc == 0:
>         return Arguments([], argc)
>     elif argc == 1:
>         return Arguments([frame.pop()], argc)
>     elif argc == 2:
>         b = frame.pop()
>         a = frame.pop()
>         return Arguments([a, b], argc)
>     assert False
>
> Since Clojure only supports up to 20 positional arguments, that'll work
> just fine. Now the last part of my trace consists of this:
>
> +266: label(p0, i26, p5, p7, p15, p17, i21, i25, descr=TargetToken
> (4302275472))
> debug_merge_point(0, 0, 'NO_OP')
> debug_merge_point(0, 0, 'PUSH_LOCAL 0')
> debug_merge_point(0, 0, 'PUSH_LOCAL 2')
> debug_merge_point(0, 0, 'EQ')
> +280: i27 = int_eq(i21, i26)
> guard_false(i27, descr=<Guard0x1006f6480>) [p0, p5, p7, p15, p17, i26]
> debug_merge_point(0, 0, 'COND_JMP 26')
> debug_merge_point(0, 0, 'PUSH_LOCAL 0')
> debug_merge_point(0, 0, 'PUSH_CONST 1')
> debug_merge_point(0, 0, 'PUSH_CONST 2')
> debug_merge_point(0, 0, 'INVOKE 2')
> debug_merge_point(1, 1, 'ADD')
> +289: i28 = int_add(i25, i26)
> debug_merge_point(1, 1, 'RETURN')
> debug_merge_point(0, 0, 'STORE_LOCAL 0')
> debug_merge_point(0, 0, 'JMP 6')
> debug_merge_point(0, 0, 'NO_OP')
> +295: jump(p0, i28, p5, p7, p15, p17, i21, i25, descr=TargetToken
> (4302275472))
>
> Which is exactly what I was looking for, an add and an eq.
>
> Thanks for the help everyone!
>
> Timothy
>
>
>
> On Tue, Feb 25, 2014 at 2:56 AM, Armin Rigo <arigo at tunes.org> wrote:
>
>> Hi Maciej,
>>
>> On 25 February 2014 09:09, Maciej Fijalkowski <fijall at gmail.com> wrote:
>> > ugh that looks really odd, why is p67 not removed escapes my attention
>>
>> Because we do setarrayitem and getarrayitem on non-constant indexes.
>>
>> > On Tue, Feb 25, 2014 at 6:36 AM, Timothy Baldridge <
>> tbaldridge at gmail.com> wrote:
>> >> I'm attaching a copy of my latest trace. The part I'm not happy with
>> is at
>> >> the end of the trace:
>>
>> We need tricks to avoid allocating the frame when we *leave* the
>> function.  In PyPy it can only be done if we know for sure that nobody
>> can potentially grab a reference to the frame for later (e.g. via
>> exceptions).  I'm unsure to remember the latest version of this logic,
>> but there were several ones...
>>
>>
>> A bientôt,
>>
>> Armin.
>>
>
>
>
> --
> "One of the main causes of the fall of the Roman Empire was that-lacking
> zero-they had no way to indicate successful termination of their C
> programs."
> (Robert Firth)
>



-- 
"One of the main causes of the fall of the Roman Empire was that-lacking
zero-they had no way to indicate successful termination of their C
programs."
(Robert Firth)
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.python.org/pipermail/pypy-dev/attachments/20140225/3f335b4d/attachment-0001.html>