This is the mail archive of the gcc-patches@gcc.gnu.org mailing list for the GCC project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: [PATCH] Do not allow to inline ifunc resolvers (PR ipa/81128).


> diff --git a/gcc/ipa-visibility.c b/gcc/ipa-visibility.c
> index d5a3ae56c46..69e6e295d55 100644
> --- a/gcc/ipa-visibility.c
> +++ b/gcc/ipa-visibility.c
> @@ -97,7 +97,8 @@ non_local_p (struct cgraph_node *node, void *data ATTRIBUTE_UNUSED)
>            && !DECL_EXTERNAL (node->decl)
>            && !node->externally_visible
>            && !node->used_from_other_partition
> -          && !node->in_other_partition);
> +          && !node->in_other_partition
> +          && !lookup_attribute ("ifunc", DECL_ATTRIBUTES (node->decl)));
>  }
>  
>  /* Return true when function can be marked local.  */
> 
> It's questionable if local.local can be true for ifunc function? If can, one would need to
> move check for ifunc aerly in:
> /* Return function availability.  See cgraph.h for description of individual
>    return values.  */
> enum availability
> cgraph_node::get_availability (symtab_node *ref)
> {
>   if (ref)
>     {
>       cgraph_node *cref = dyn_cast <cgraph_node *> (ref);
>       if (cref)
> 	ref = cref->global.inlined_to;
>     }
>   enum availability avail;
>   if (!analyzed)
>     avail = AVAIL_NOT_AVAILABLE;
>   else if (local.local)
>     avail = AVAIL_LOCAL;
>   else if (global.inlined_to)
>     avail = AVAIL_AVAILABLE;
>   else if (transparent_alias)
>     ultimate_alias_target (&avail, ref);
>   else if (lookup_attribute ("ifunc", DECL_ATTRIBUTES (decl)))
>     avail = AVAIL_INTERPOSABLE;
> 
> ...
> 
> What solution do you prefer Honza?

Probably just update non_local_p to also check that availability is at least AVAIL_AVAILABLE.
Then we will have one place to collect such a side cases where !EXTERNAL function can be
interposed.

Honza
> 
> Thanks,
> Martin
> 
> > 
> > Honza
> >> Martin
> >>
> >> gcc/ChangeLog:
> >>
> >> 2017-06-22  Martin Liska  <mliska@suse.cz>
> >>
> >> 	* ipa-inline.c (can_inline_edge_p): Return false for ifunc fns.
> >> 	* ipa-visibility.c (can_replace_by_local_alias): Likewise.
> >>
> >> gcc/c-family/ChangeLog:
> >>
> >> 2017-06-22  Martin Liska  <mliska@suse.cz>
> >>
> >> 	* c-attribs.c (handle_alias_ifunc_attribute): Append ifunc alias
> >> 	to a function declaration.
> >>
> >> gcc/testsuite/ChangeLog:
> >>
> >> 2017-06-22  Martin Liska  <mliska@suse.cz>
> >>
> >> 	* gcc.target/i386/pr81128.c: New test.
> >> ---
> >>  gcc/c-family/c-attribs.c                | 11 ++++--
> >>  gcc/ipa-inline.c                        |  2 +
> >>  gcc/ipa-visibility.c                    |  3 +-
> >>  gcc/testsuite/gcc.target/i386/pr81128.c | 65 +++++++++++++++++++++++++++++++++
> >>  4 files changed, 77 insertions(+), 4 deletions(-)
> >>  create mode 100644 gcc/testsuite/gcc.target/i386/pr81128.c
> >>
> >>
> > 
> >> diff --git a/gcc/c-family/c-attribs.c b/gcc/c-family/c-attribs.c
> >> index 2b6845f2cbd..626ffa1cde7 100644
> >> --- a/gcc/c-family/c-attribs.c
> >> +++ b/gcc/c-family/c-attribs.c
> >> @@ -1846,9 +1846,14 @@ handle_alias_ifunc_attribute (bool is_alias, tree *node, tree name, tree args,
> >>  	TREE_STATIC (decl) = 1;
> >>  
> >>        if (!is_alias)
> >> -	/* ifuncs are also aliases, so set that attribute too.  */
> >> -	DECL_ATTRIBUTES (decl)
> >> -	  = tree_cons (get_identifier ("alias"), args, DECL_ATTRIBUTES (decl));
> >> +	{
> >> +	  /* ifuncs are also aliases, so set that attribute too.  */
> >> +	  DECL_ATTRIBUTES (decl)
> >> +	    = tree_cons (get_identifier ("alias"), args,
> >> +			 DECL_ATTRIBUTES (decl));
> >> +	  DECL_ATTRIBUTES (decl) = tree_cons (get_identifier ("ifunc"),
> >> +					      NULL, DECL_ATTRIBUTES (decl));
> >> +	}
> >>      }
> >>    else
> >>      {
> >> diff --git a/gcc/ipa-inline.c b/gcc/ipa-inline.c
> >> index fb20d3723cc..588fa9c41e4 100644
> >> --- a/gcc/ipa-inline.c
> >> +++ b/gcc/ipa-inline.c
> >> @@ -370,6 +370,8 @@ can_inline_edge_p (struct cgraph_edge *e, bool report,
> >>        e->inline_failed = CIF_ATTRIBUTE_MISMATCH;
> >>        inlinable = false;
> >>      }
> >> +  else if (lookup_attribute ("ifunc", DECL_ATTRIBUTES (e->callee->decl)))
> >> +      inlinable = false;
> >>    /* Check if caller growth allows the inlining.  */
> >>    else if (!DECL_DISREGARD_INLINE_LIMITS (callee->decl)
> >>  	   && !disregard_limits
> >> diff --git a/gcc/ipa-visibility.c b/gcc/ipa-visibility.c
> >> index d5a3ae56c46..79d05b41085 100644
> >> --- a/gcc/ipa-visibility.c
> >> +++ b/gcc/ipa-visibility.c
> >> @@ -345,7 +345,8 @@ can_replace_by_local_alias (symtab_node *node)
> >>    
> >>    return (node->get_availability () > AVAIL_INTERPOSABLE
> >>  	  && !decl_binds_to_current_def_p (node->decl)
> >> -	  && !node->can_be_discarded_p ());
> >> +	  && !node->can_be_discarded_p ()
> >> +	  && !lookup_attribute ("ifunc", DECL_ATTRIBUTES (node->decl)));
> >>  }
> >>  
> >>  /* Return true if we can replace reference to NODE by local alias
> >> diff --git a/gcc/testsuite/gcc.target/i386/pr81128.c b/gcc/testsuite/gcc.target/i386/pr81128.c
> >> new file mode 100644
> >> index 00000000000..90a567ad690
> >> --- /dev/null
> >> +++ b/gcc/testsuite/gcc.target/i386/pr81128.c
> >> @@ -0,0 +1,65 @@
> >> +/* PR ipa/81128 */
> >> +/* { dg-do run } */
> >> +/* { dg-options "-O3" } */
> >> +/* { dg-require-ifunc "" } */
> >> +
> >> +
> >> +#include <stdio.h>
> >> +#include <stdlib.h>
> >> +#include <time.h>
> >> +
> >> +int resolver_fn = 0;
> >> +int resolved_fn = 0;
> >> +
> >> +static inline void
> >> +do_it_right_at_runtime_A ()
> >> +{
> >> +  resolved_fn++;
> >> +}
> >> +
> >> +static inline void
> >> +do_it_right_at_runtime_B ()
> >> +{
> >> +  resolved_fn++;
> >> +}
> >> +
> >> +static inline void do_it_right_at_runtime (void);
> >> +
> >> +void do_it_right_at_runtime (void)
> >> +  __attribute__ ((ifunc ("resolve_do_it_right_at_runtime")));
> >> +
> >> +static void (*resolve_do_it_right_at_runtime (void)) (void)
> >> +{
> >> +  srand (time (NULL));
> >> +  int r = rand ();
> >> +  resolver_fn++;
> >> +
> >> +  /* Use intermediate variable to get a warning for non-matching
> >> +   * prototype. */
> >> +  typeof(do_it_right_at_runtime) *func;
> >> +  if (r & 1)
> >> +    func = do_it_right_at_runtime_A;
> >> +  else
> >> +    func = do_it_right_at_runtime_B;
> >> +
> >> +  return (void *) func;
> >> +}
> >> +
> >> +int
> >> +main (void)
> >> +{
> >> +  const unsigned int ITERS = 10;
> >> +
> >> +  for (int i = ITERS; i > 0; i--)
> >> +    {
> >> +      do_it_right_at_runtime ();
> >> +    }
> >> +
> >> +  if (resolver_fn != 1)
> >> +    __builtin_abort ();
> >> +
> >> +  if (resolved_fn != 10)
> >> +    __builtin_abort ();
> >> +
> >> +  return 0;
> >> +}
> >>
> > 


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]