Re: [PATCH] ipa: silent -Wodr notes with -w

["Martin Liška" <mliska@suse.cz>]

On 2/9/23 01:10, Jan Hubicka wrote:
>>> On 2/1/23 15:26, Martin Jambor wrote:
>>>> Hi,
>>>>
>>>> On Fri, Dec 02 2022, Martin Liška wrote:
>>>>> If -w is used, warn_odr properly sets *warned = false and
>>>>> so it should be preserved when calling warn_types_mismatch.
>>>>>
>>>>> Noticed that during a LTO reduction where I used -w.
>>>>>
>>>>> Patch can bootstrap on x86_64-linux-gnu and survives regression tests.
>>>>>
>>>>> Ready to be installed?
>>>>> Thanks,
>>>>> Martin
>>>>>
>>>>> gcc/ChangeLog:
>>>>>
>>>>> 	* ipa-devirt.cc (odr_types_equivalent_p): Respect *warned
>>>>> 	value if set.
>>>>
>>>
>>> Hi.
>>>
>>>> Sorry for skipping this for so long, usually ODR stuff is... interesting
>>>> to the point I gladly leave it to Honza.
>>>
>>> Makes sense, however, he's not much active when it comes to patch review.
>>
>> Sorry, I was confused by the patch and delayed reply to figure out what
>> you are trying to fix.  Indeed the dererence is missing here, however
>> every caller that sets warn to true should also set warned to non-NULL.
>> So indeed derefernce is missing, but I think the check for
>> warned == NULL should not be necessary.
> 
> This seems to bootstrap with LTO.  I am not sure what testcase you
> looked in, but unless there as a good reason to include the NULL check,
> I would rmeove it as it makes it harder to see what is going on.

Hi.

Thanks for the patch. Apparently, I noticed that during reduction of a test-case
where I used -w in order to silent all warnings.

So go ahead with your patch.

Martin

> 
> honza
> 
> diff --git a/gcc/ipa-devirt.cc b/gcc/ipa-devirt.cc
> index 14cf132c767..819860258d1 100644
> --- a/gcc/ipa-devirt.cc
> +++ b/gcc/ipa-devirt.cc
> @@ -1221,6 +1221,9 @@ odr_types_equivalent_p (tree t1, tree t2, bool warn, bool *warned,
>  			hash_set<type_pair> *visited,
>  			location_t loc1, location_t loc2)
>  {
> +  /* If we are asked to warn, we need warned to keep track if warning was
> +     output.  */
> +  gcc_assert (!warn || warned);
>    /* Check first for the obvious case of pointer identity.  */
>    if (t1 == t2)
>      return true;
> @@ -1300,7 +1303,7 @@ odr_types_equivalent_p (tree t1, tree t2, bool warn, bool *warned,
>  	      warn_odr (t1, t2, NULL, NULL, warn, warned,
>  			G_("it is defined as a pointer to different type "
>  			   "in another translation unit"));
> -	      if (warn && (warned == NULL || *warned))
> +	      if (warn && *warned)
>  	        warn_types_mismatch (TREE_TYPE (t1), TREE_TYPE (t2),
>  				     loc1, loc2);
>  	      return false;
> @@ -1315,7 +1318,7 @@ odr_types_equivalent_p (tree t1, tree t2, bool warn, bool *warned,
>  	  warn_odr (t1, t2, NULL, NULL, warn, warned,
>  		    G_("a different type is defined "
>  		       "in another translation unit"));
> -	  if (warn && (warned == NULL || *warned))
> +	  if (warn && *warned)
>  	    warn_types_mismatch (TREE_TYPE (t1), TREE_TYPE (t2), loc1, loc2);
>  	  return false;
>  	}
> @@ -1333,7 +1336,7 @@ odr_types_equivalent_p (tree t1, tree t2, bool warn, bool *warned,
>  	    warn_odr (t1, t2, NULL, NULL, warn, warned,
>  		      G_("a different type is defined in another "
>  			 "translation unit"));
> -	    if (warn && (warned == NULL || *warned))
> +	    if (warn && *warned)
>  	      warn_types_mismatch (TREE_TYPE (t1), TREE_TYPE (t2), loc1, loc2);
>  	  }
>  	gcc_assert (TYPE_STRING_FLAG (t1) == TYPE_STRING_FLAG (t2));
> @@ -1375,7 +1378,7 @@ odr_types_equivalent_p (tree t1, tree t2, bool warn, bool *warned,
>  	  warn_odr (t1, t2, NULL, NULL, warn, warned,
>  		    G_("has different return value "
>  		       "in another translation unit"));
> -	  if (warn && (warned == NULL || *warned))
> +	  if (warn && *warned)
>  	    warn_types_mismatch (TREE_TYPE (t1), TREE_TYPE (t2), loc1, loc2);
>  	  return false;
>  	}
> @@ -1398,7 +1401,7 @@ odr_types_equivalent_p (tree t1, tree t2, bool warn, bool *warned,
>  		  warn_odr (t1, t2, NULL, NULL, warn, warned,
>  			    G_("has different parameters in another "
>  			       "translation unit"));
> -		  if (warn && (warned == NULL || *warned))
> +		  if (warn && *warned)
>  		    warn_types_mismatch (TREE_VALUE (parms1),
>  					 TREE_VALUE (parms2), loc1, loc2);
>  		  return false;
> @@ -1484,7 +1487,7 @@ odr_types_equivalent_p (tree t1, tree t2, bool warn, bool *warned,
>  		    warn_odr (t1, t2, f1, f2, warn, warned,
>  			      G_("a field of same name but different type "
>  				 "is defined in another translation unit"));
> -		    if (warn && (warned == NULL || *warned))
> +		    if (warn && *warned)
>  		      warn_types_mismatch (TREE_TYPE (f1), TREE_TYPE (f2), loc1, loc2);
>  		    return false;
>  		  }