[Bug c/89341] [7/8/9 Regression] ICE in get, at cgraph.h:1332

[dmalcolm at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89341

--- Comment #5 from David Malcolm  ---
Both decls of "foo" are using the same FUNCTION_DECL.

node->alias is set in varasm.c: assemble_alias here:

5991cgraph_node::get_create (decl)->alias = true;

when processing the second decl of "foo" here:

 void foo ();

since the FUNCTION_DECL for "foo" has an "alias" attribute, given to it by
handle_weakref_attribute when parsing the first decl of here:

__attribute__((weakref("bar")))
static void foo () { }

[Bug c/89341] [7/8/9 Regression] ICE in get, at cgraph.h:1332

[dmalcolm at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89341

--- Comment #4 from David Malcolm  ---
The -Wattributes warning would be emitted here in cgraphunit.c:
process_function_and_variable_attributes:

777   if (lookup_attribute ("weakref", DECL_ATTRIBUTES (decl))
778   && (node->definition && !node->alias))
779 {
780   warning_at (DECL_SOURCE_LOCATION (node->decl),
OPT_Wattributes,
781   "% attribute ignored"
782   " because function is defined");
783   DECL_WEAK (decl) = 0;
784   DECL_ATTRIBUTES (decl) = remove_attribute ("weakref",
785  DECL_ATTRIBUTES
(decl));
786 }

but the alias stops the clause from firing:

(gdb) p node
$3 = 
(gdb) p node->definition
$4 = 1
(gdb) p node->alias
$5 = 1

The alias exclusion was added to the warning in r174952 (aka
c70f46b057cd12973d33c01c8fa0da5c14ba3944) by Honza:

@@ -880,7 +977,7 @@ process_function_and_variable_attributes (struct
cgraph_node *first,
 cgraph_mark_needed_node (node);
}
   if (lookup_attribute ("weakref", DECL_ATTRIBUTES (decl))
- && node->local.finalized)
+ && (node->local.finalized && !node->alias))
{
  warning_at (DECL_SOURCE_LOCATION (node->decl), OPT_Wattributes,
  "% attribute ignored"

[Bug c/89341] [7/8/9 Regression] ICE in get, at cgraph.h:1332

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89341

Jakub Jelinek  changed:

   What|Removed |Added

 CC||hubicka at gcc dot gnu.org,
   ||jakub at gcc dot gnu.org
   Target Milestone|--- |7.5
Summary|ICE in get, at  |[7/8/9 Regression] ICE in
   |cgraph.h:1332   |get, at cgraph.h:1332

--- Comment #3 from Jakub Jelinek  ---
This used to be accepted before r154115 (so e.g. in GCC 4.2), then it started
to ICE:
pr89341.c:3:1: internal compiler error: in function_and_variable_visibility, at
ipa.c:662
then (likely) r169332 started rejecting this:
pr89341.c:2:13: warning: ‘weakref’ attribute ignored because function is
defined [-Wattributes]
pr89341.c:2:13: error: ‘foo’ aliased to undefined symbol ‘bar’
then r174952 started to ICE on this again.