-fdump-passes -fenable-xxx=func_name_list

Xinliang David Li davidxl@google.com
Tue Jun 7 20:39:00 GMT 2011


The dump-pass patch with test case.

David

On Tue, Jun 7, 2011 at 11:54 AM, Xinliang David Li <davidxl@google.com> wrote:
> Please review the attached two patches.
>
> In the first patch, gate functions are cleaned up. All the per
> function legality checks are moved into the executor and the
> optimization heuristic checks (optimize for size) remain in the
> gators. These allow the the following overriding order:
>
>    common flags (O2, -ftree-vrp, -fgcse etc)   <---  compiler
> heuristic (optimize for size/speed) <--- -fdisable/enable forcing pass
> options  <--- legality check
>
> Testing under going. Ok for trunk?
>
> Thanks,
>
> David
>
> On Tue, Jun 7, 2011 at 9:24 AM, Xinliang David Li <davidxl@google.com> wrote:
>> Ok -- that sounds good.
>>
>> David
>>
>> On Tue, Jun 7, 2011 at 3:10 AM, Richard Guenther
>> <richard.guenther@gmail.com> wrote:
>>> On Mon, Jun 6, 2011 at 6:00 PM, Xinliang David Li <davidxl@google.com> wrote:
>>>> On Mon, Jun 6, 2011 at 4:38 AM, Richard Guenther
>>>> <richard.guenther@gmail.com> wrote:
>>>>> On Thu, Jun 2, 2011 at 9:12 AM, Xinliang David Li <davidxl@google.com> wrote:
>>>>>> This is the version of the patch that walks through pass lists.
>>>>>>
>>>>>> Ok with this one?
>>>>>
>>>>> +/* Dump all optimization passes.  */
>>>>> +
>>>>> +void
>>>>> +dump_passes (void)
>>>>> +{
>>>>> +  struct cgraph_node *n, *node = NULL;
>>>>> +  tree save_fndecl = current_function_decl;
>>>>> +
>>>>> +  fprintf (stderr, "MAX_UID = %d\n", cgraph_max_uid);
>>>>>
>>>>> this isn't accurate info - cloning can cause more cgraph nodes to
>>>>> appear (it also looks completely unrelated to dump_passes ...).
>>>>> Please drop it.
>>>>
>>>> Ok.
>>>>
>>>>
>>>>>
>>>>> +  create_pass_tab();
>>>>> +  gcc_assert (pass_tab);
>>>>>
>>>>> you have quite many asserts of this kind - we don't want them when
>>>>> the previous stmt as in this case indicates everything is ok.
>>>>
>>>> ok.
>>>>
>>>>>
>>>>> +  push_cfun (DECL_STRUCT_FUNCTION (node->decl));
>>>>>
>>>>> this has side-effects, I'm not sure we want this here.  Why do you
>>>>> need it?  Probably because of
>>>>>
>>>>> +  is_really_on = override_gate_status (pass, current_function_decl, is_on);
>>>>>
>>>>> ?  But that is dependent on the function given which should have no
>>>>> effect (unless it is overridden globally in which case override_gate_status
>>>>> and friends should deal with a NULL cfun).
>>>>
>>>> As we discussed, currently some pass gate functions depend on per node
>>>> information -- those checks need to be pushed into execute functions.
>>>> I would like to clean those up later -- at which time, the push/pop
>>>> can be removed.
>>>
>>> I'd like to do it the other way around, first clean up the gate functions then
>>> drop in this patch without the cfun push/pop.  The revised patch looks ok
>>> to me with the cfun push/pop removed.
>>>
>>> Thanks,
>>> Richard.
>>>
>>>>>
>>>>> I don't understand why you need another table mapping pass to name
>>>>> when pass->name is available and the info is trivially re-constructible.
>>>>
>>>> This is needed as the pass->name is not the canonicalized name (i.e.,
>>>> not with number suffix etc), so the extra mapping from id to
>>>> normalized name is needed.
>>>>
>>>> Thanks,
>>>>
>>>> David
>>>>
>>>>>
>>>>> Thanks,
>>>>> Richard.
>>>>>
>>>>>> David
>>>>>>
>>>>>> On Wed, Jun 1, 2011 at 12:45 PM, Xinliang David Li <davidxl@google.com> wrote:
>>>>>>> On Wed, Jun 1, 2011 at 12:29 PM, Richard Guenther
>>>>>>> <richard.guenther@gmail.com> wrote:
>>>>>>>> On Wed, Jun 1, 2011 at 6:16 PM, Xinliang David Li <davidxl@google.com> wrote:
>>>>>>>>> On Wed, Jun 1, 2011 at 1:51 AM, Richard Guenther
>>>>>>>>> <richard.guenther@gmail.com> wrote:
>>>>>>>>>> On Wed, Jun 1, 2011 at 1:34 AM, Xinliang David Li <davidxl@google.com> wrote:
>>>>>>>>>>> The following patch implements the a new option that dumps gcc PASS
>>>>>>>>>>> configuration. The sample output is attached.  There is one
>>>>>>>>>>> limitation: some placeholder passes that are named with '*xxx' are
>>>>>>>>>>> note registered thus they are not listed. They are not important as
>>>>>>>>>>> they can not be turned on/off anyway.
>>>>>>>>>>>
>>>>>>>>>>> The patch also enhanced -fenable-xxx and -fdisable-xx to allow a list
>>>>>>>>>>> of function assembler names to be specified.
>>>>>>>>>>>
>>>>>>>>>>> Ok for trunk?
>>>>>>>>>>
>>>>>>>>>> Please split the patch.
>>>>>>>>>>
>>>>>>>>>> I'm not too happy how you dump the pass configuration.  Why not simply,
>>>>>>>>>> at a _single_ place, walk the pass tree?  Instead of doing pieces of it
>>>>>>>>>> at pass execution time when it's not already dumped - that really looks
>>>>>>>>>> gross.
>>>>>>>>>
>>>>>>>>> Yes, that was the original plan -- but it has problems
>>>>>>>>> 1) the dumper needs to know the root pass lists -- which can change
>>>>>>>>> frequently -- it can be a long term maintanance burden;
>>>>>>>>> 2) the centralized dumper needs to be done after option processing
>>>>>>>>> 3) not sure if gate functions have any side effects or have dependencies on cfun
>>>>>>>>>
>>>>>>>>> The proposed solutions IMHO is not that intrusive -- just three hooks
>>>>>>>>> to do the dumping and tracking indentation.
>>>>>>>>
>>>>>>>> Well, if you have a CU that is empty or optimized to nothing at some point
>>>>>>>> you will not get a complete pass list.  I suppose optimize attributes might
>>>>>>>> also confuse output.  Your solution might not be that intrusive
>>>>>>>> but it is still ugly.  I don't see 1) as an issue, for 2) you can just call the
>>>>>>>> dumping from toplev_main before calling do_compile (), 3) gate functions
>>>>>>>> shouldn't have side-effects, but as they could gate on optimize_for_speed ()
>>>>>>>> your option summary output will be bogus anyway.
>>>>>>>>
>>>>>>>> So - what is the output intended for if it isn't reliable?
>>>>>>>
>>>>>>> This needs to be cleaned up at some point -- the gate function should
>>>>>>> behave the same for all functions and per-function decisions need to
>>>>>>> be pushed down to the executor body.  I will try to rework the patch
>>>>>>> as you suggested to see if there are problems.
>>>>>>>
>>>>>>> David
>>>>>>>
>>>>>>>
>>>>>>>>
>>>>>>>> Richard.
>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> The documentation should also link this option to the -fenable/disable
>>>>>>>>>> options as obviously the pass names in that dump are those to be
>>>>>>>>>> used for those flags (and not readily available anywhere else).
>>>>>>>>>
>>>>>>>>> Ok.
>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> I also think that it would be way more useful to note in the individual
>>>>>>>>>> dump files the functions (at the place they would usually appear) that
>>>>>>>>>> have the pass explicitly enabled/disabled.
>>>>>>>>>
>>>>>>>>> Ok -- for ipa passes or tree/rtl passes where all functions are
>>>>>>>>> explicitly disabled.
>>>>>>>>>
>>>>>>>>> Thanks,
>>>>>>>>>
>>>>>>>>> David
>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> Richard.
>>>>>>>>>>
>>>>>>>>>>> Thanks,
>>>>>>>>>>>
>>>>>>>>>>> David
>>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>
>
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