New options to disable/enable any pass for any functions (issue4550056)

[Xinliang David Li]

On Thu, May 26, 2011 at 2:04 AM, Richard Guenther
<richard.guenther@gmail.com> wrote:
> On Wed, May 25, 2011 at 6:53 PM, Joseph S. Myers
> <joseph@codesourcery.com> wrote:
>> On Wed, 25 May 2011, Xinliang David Li wrote:
>>
>>> Ping. The link to the message:
>>>
>>> http://gcc.gnu.org/ml/gcc-patches/2011-05/msg01303.html
>>
>> I don't consider this an option handling patch.  Patches adding whole new
>> features involving new options should be reviewed by maintainers for the
>> part of the compiler relevant to those features (since there isn't a pass
>> manager maintainer, I guess that means middle-end).
>
> Hmm, I suppose then you reviewed the option handling parts and they
> are ok?  Those globbing options always cause headache to me.
>
> +-fenable-ipa-@var{pass} @gol
> +-fenable-rtl-@var{pass} @gol
> +-fenable-rtl-@var{pass}=@var{range-list} @gol
> +-fenable-tree-@var{pass} @gol
>
> so, no -fenable-tree-@var{pass}=@var{range-list}?
>

Missed. Will add.


> Does the pass name match 1:1 with the dump file name?  In which
> case

Yes.

>
> +Disable ipa pass @var{pass}. @var{pass} is the pass name. If the same
> pass is statically invoked in the compiler multiple times, the pass
> name should be appended with a sequential number starting from 1.
>
> isn't true as passes that are invoked only a single time lack the number
> suffix (yes, I'd really like that to be changed ...)

Yes, pass with single static instance does not need number suffix.

>
> Please break likes also in .texi files and stick to 80 columns.

Done.

>  Please
> document that these options are debugging options and regular
> options for enabling/disabling passes should be used.  I would suggest
> to group documentation differently and document -fenable-* and
> -fdisable-*, thus,
>
> + -fdisable-@var{kind}-@var{pass}
> + -fenable-@var{kind}-@var{pass}
>
> Even in .texi files please two spaces after a full-stop.

Done

>
> +extern void enable_disable_pass (const char *, bool);
>
> I'd rather have both enable_pass and disable_pass ;)

Ok.

>
> +struct function;
> +extern void pass_dump_function_header (FILE *, tree, struct function *);
>
> that's odd and probably should be split out, the function should
> maybe reside in tree-pretty-print.c.

Ok.

>
> Index: tree-ssa-loop-ivopts.c
> ===================================================================
> --- tree-ssa-loop-ivopts.c      (revision 173837)
> +++ tree-ssa-loop-ivopts.c      (working copy)
> @@ -3968,7 +3968,7 @@ get_computation_cost_at (struct ivopts_d
>
> well - doesn't belong here ;)

Sorry -- many things in the same client -- not needed with your latest
change anyway.

>
> +static hashval_t
> +passr_hash (const void *p)
> +{
> +  const struct pass_registry *const s = (const struct pass_registry *const) p;
> +  return htab_hash_string (s->unique_name);
> +}
> +
> +/* Hash equal function  */
> +
> +static int
> +passr_eq (const void *p1, const void *p2)
> +{
> +  const struct pass_registry *const s1 = (const struct pass_registry
> *const) p1;
> +  const struct pass_registry *const s2 = (const struct pass_registry
> *const) p2;
> +
> +  return !strcmp (s1->unique_name, s2->unique_name);
> +}
>
> you can use htab_hash_string and strcmp directly, no need for these
> wrappers.

The hashtable entry is not string in this case. It is pass_registry,
thus the wrapper.

>
> +void
> +register_pass_name (struct opt_pass *pass, const char *name)
>
> doesn't seem to need exporting, so don't and make it static.

Done.

>
> +  if (!pass_name_tab)
> +    pass_name_tab = htab_create (10, passr_hash, passr_eq, NULL);
>
> see above, the initial size should be larger - we have 223 passes at the
> moment, so use 256.

Done.

>
> +  else
> +    return; /* Ignore plugin passes.  */
>
> ?  You mean they might clash?

Yes, name clash.

>
> +struct opt_pass *
> +get_pass_by_name (const char *name)
>
> doesn't need exporting either.

Done.

>
> +      if (is_enable)
> +        error ("unrecognized option -fenable");
> +      else
> +        error ("unrecognized option -fdisable");
>
> I think that should be fatal_error - Joseph?
>
> +      if (is_enable)
> +        error ("unknown pass %s specified in -fenable", phase_name);
> +      else
> +        error ("unknown pass %s specified in -fdisble", phase_name);
>
> likewise.
>
> +      if (!enabled_pass_uid_range_tab)
> +       enabled_pass_uid_range_tab = htab_create (10, pass_hash, pass_eq, NULL);
>
> instead of using a hashtable here please use a VEC indexed by
> the static_pass_number which shoud speed up

Ok.  The reason I did not use it is because in most of the cases, the
htab will be very small -- it is determined by the number of passes
specified in the command line, while the VEC requires allocating const
size array. Not an issue as long as by default the array is not
allocated.

>
> +static bool
> +is_pass_explicitly_enabled_or_disabled (struct opt_pass *pass,
> +                                       tree func, htab_t tab)
> +{
> +  struct uid_range **slot, *range, key;
> +  int cgraph_uid;
> +
> +  if (!tab)
> +    return false;
> +
> +  key.pass = pass;
> +  slot = (struct uid_range **) htab_find_slot (tab, &key, NO_INSERT);
> +  if (!slot || !*slot)
> +    return false;
>
> and simplify the code quite a bit.
>
> +  cgraph_uid = func ? cgraph_get_node (func)->uid : 0;
>
> note that cgraph uids are recycled, so it might not be the best idea
> to use them as discriminator (though I don't have a good idea how
> to represent ranges without them).

Yes. It is not a big problem as the blind search does not need to know
the id->name mapping. Once the id s found, it can be easily discovered
via dump.

>
> +  explicitly_enabled = is_pass_explicitly_enabled (pass,
> current_function_decl);
> +  explicitly_disabled = is_pass_explicitly_disabled (pass,
> current_function_decl);
> +
>   current_pass = pass;
>
>   /* Check whether gate check should be avoided.
>      User controls the value of the gate through the parameter
> "gate_status". */
>   gate_status = (pass->gate == NULL) ? true : pass->gate();
> +  gate_status = !explicitly_disabled && (gate_status || explicitly_enabled);
>
> so explicitly disabling wins over explicit enabling ;)  I think this
> implementation detail and the fact that you always query both
> hints at that the interface should be like
>
> gate_status = override_gate_status (pass, current_function_decl, gate_status);

Done.

>
> instead.
>
> Thus, please split out the function header dumping changes and rework
> the rest of the patch as suggested.

Split out. The new patch is attached.

Ok after testing is done?

Thanks,

David

>
> Thanks,
> Richard.
>
>> --
>> Joseph S. Myers
>> joseph@codesourcery.com
>>
>
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