On 06/27/2017 04:57 PM, Jan Hubicka wrote:
>> Hello.
>>
>> Currently ifunc is interpreted as normal alias by IPA optimizations. That's
>> problematic
>> as should not consider ifunc alias as candidate for inlining, or redirection.
>>
>> Patch can bootstrap on ppc64le-redhat-linux and survives regression tests.
>> And survives MVC tests on x86_64-linux-gnu.
>>
>> Ready to be installed?
>
> Wasn't this supposed to go with arranging availability to be
> AVAIL_INTERPOSABLE
> (as the target will be interposed by linker to the corect target)
Should work, there's alternative patch:
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-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?
Thanks,
Martin
>
> Honza
>> Martin
>>
>> gcc/ChangeLog:
>>
>> 2017-06-22 Martin Liska <mli...@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 <mli...@suse.cz>
>>
>> * c-attribs.c (handle_alias_ifunc_attribute): Append ifunc alias
>> to a function declaration.
>>
>> gcc/testsuite/ChangeLog:
>>
>> 2017-06-22 Martin Liska <mli...@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;
>> +}
>>
>
