Re: Dump before flag

[Richard Guenther <richard.guenther@gmail.com>]

On Thu, Jun 9, 2011 at 12:31 AM, Xinliang David Li <davidxl@google.com> wrote:
> this is the patch that just removes the TODO_dump flag and forces it
> to dump. The original code cfun->last_verified = flags &
> TODO_verify_all looks weird -- depending on TODO_dump is set or not,
> the behavior of the update is different (when no other todo flags is
> set).
>
> Ok for trunk?

-ENOPATCH.

Richard.

> David
>
> On Wed, Jun 8, 2011 at 9:52 AM, Xinliang David Li <davidxl@google.com> wrote:
>> On Wed, Jun 8, 2011 at 2:06 AM, Richard Guenther
>> <richard.guenther@gmail.com> wrote:
>>> On Wed, Jun 8, 2011 at 1:08 AM, Xinliang David Li <davidxl@google.com> wrote:
>>>> The following is the patch that does the job. Most of the changes are
>>>> just  removing TODO_dump_func. The major change is in passes.c and
>>>> tree-pass.h.
>>>>
>>>> -fdump-xxx-yyy-start       <-- dump before TODO_start
>>>> -fdump-xxx-yyy-before    <-- dump before main pass after TODO_pass
>>>> -fdump-xxx-yyy-after       <-- dump after main pass before TODO_finish
>>>> -fdump-xxx-yyy-finish      <-- dump after TODO_finish
>>>
>>> Can we bikeshed a bit more about these names?
>>
>> These names may be less confusing:
>>
>> before_preparation
>> before
>> after
>> after_cleanup
>>
>> David
>>
>>> "start" and "before"
>>> have no semantical difference to me ... as the dump before TODO_start
>>> of a pass and the dump after TODO_finish of the previous pass are
>>> identical (hopefully ;)), maybe merge those into a -between flag?
>>> If you'd specify it for a single pass then you'd get both -start and -finish
>>> (using your naming scheme).  Splitting that dump(s) to different files
>>> then might make sense (not sure about the name to use).
>>>
>>> Note that I find it extremely useful to have dumping done in
>>> chronological order - splitting some of it to different files destroys
>>> this, especially a dump after TODO_start or before TODO_finish
>>> should appear in the same file (or we could also start splitting
>>> individual TODO_ output into sub-dump-files).  I guess what would
>>> be nice instread would be a fancy dump-file viewer that could
>>> show diffs, hide things like SCEV output, etc.
>>>
>>> I suppose a patch that removes the dump TODO and unconditionally
>>> dumps at the current point would be a good preparation for this
>>> enhancing patch.
>>>
>>> Richard.
>>>
>>>> The default is 'finish'.
>>>>
>>>> Does it look ok?
>>>>
>>>> Thanks,
>>>>
>>>> David
>>>>
>>>> On Tue, Jun 7, 2011 at 2:36 AM, Richard Guenther
>>>> <richard.guenther@gmail.com> wrote:
>>>>> On Mon, Jun 6, 2011 at 6:20 PM, Xinliang David Li <davidxl@google.com> wrote:
>>>>>>>
>>>>>>> Your patch doesn't really improve this but adds to the confusion.
>>>>>>>
>>>>>>> +  /* Override dump TODOs.  */
>>>>>>> +  if (dump_file && (pass->todo_flags_finish & TODO_dump_func)
>>>>>>> +      && (dump_flags & TDF_BEFORE))
>>>>>>> +    {
>>>>>>> +      pass->todo_flags_finish &= ~TODO_dump_func;
>>>>>>> +      pass->todo_flags_start |= TODO_dump_func;
>>>>>>> +    }
>>>>>>>
>>>>>>> and certainly writing to pass is not ok.  And the TDF_BEFORE flag
>>>>>>> looks misplaced as it controls TODOs, not dumping behavior.
>>>>>>> Yes, it's a mess right now but the above looks like a hack ontop
>>>>>>> of that mess (maybe because of it, but well ...).
>>>>>>>
>>>>>>
>>>>>> How about removing dumping TODO completely -- this can be done easily
>>>>>> -- I don't understand why pass wants extra control on the dumping if
>>>>>> user already asked for dumping -- it is annoying to see empty IR dump
>>>>>> for a pass when I want to see it.
>>>>>>
>>>>>>> At least I would have expected to also get the dump after the
>>>>>>> pass, not only the one before it with this dump flag.
>>>>>>>
>>>>>>> Now, why can't you look at the previous pass output for the
>>>>>>> before-dump (as I do usually)?
>>>>>>
>>>>>> For one thing, you need to either remember what is the previous pass,
>>>>>> or dump all passes which for large files can take very long time. Even
>>>>>> with all the dumps, you will need to eyeballing to find the previous
>>>>>> pass which may or may not have the IR dumped.
>>>>>>
>>>>>> How about removing dump TODO?
>>>>>
>>>>> Yeah, I think this would go in the right direction.  Currently some passes
>>>>> do not dump function bodies because they presumably do no IL
>>>>> modification.  But this is certainly the minority (and some passes do not
>>>>> dump bodies even though they are modifying the IL ...).
>>>>>
>>>>> So I'd say we should by default dump function bodies.
>>>>>
>>>>> Note that there are three useful dumping positions (maybe four),
>>>>> before todo-start, after todo-start, before todo-finish and after todo-finish.
>>>>> By default we'd want after todo-finish.  When we no longer dump via
>>>>> a TODO then we could indeed use dump-flags to control this
>>>>> (maybe -original for the body before todo-start).
>>>>>
>>>>> What to others think?
>>>>>
>>>>> Richard.
>>>>>
>>>>>> Thanks,
>>>>>>
>>>>>> David
>>>>>>
>>>>>>
>>>>>>>
>>>>>>> Richard.
>>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>
>