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* [Bug c/24539] New: inconsistent handling of null-valued language hooks in GCC
@ 2005-10-26 14:28 gary at intrepid dot com
2005-10-26 14:39 ` [Bug c/24539] " gary at intrepid dot com
` (3 more replies)
0 siblings, 4 replies; 5+ messages in thread
From: gary at intrepid dot com @ 2005-10-26 14:28 UTC (permalink / raw)
To: gcc-bugs
Also posted to the GCC mailing list:
http://gcc.gnu.org/ml/gcc/2005-10/msg00932.html
http://gcc.gnu.org/ml/gcc/2005-10/msg00938.html
While working with GCC's language hooks, we found that
certain places in GCC test for a null value of
lang_hooks.callgraph.expand_function, but
cgraph_expand_function() calls the hook directly:
In cgraphunit.c:
/* Expand function specified by NODE. */
static void
cgraph_expand_function (struct cgraph_node *node)
{
tree decl = node->decl;
/* We ought to not compile any inline clones. */
gcc_assert (!node->global.inlined_to);
if (flag_unit_at_a_time)
announce_function (decl);
cgraph_lower_function (node);
/* Generate RTL for the body of DECL. */
lang_hooks.callgraph.expand_function (decl);
------------
In toplev.c:
/* Disable unit-at-a-time mode for frontends not supporting callgraph
interface. */
if (flag_unit_at_a_time && ! lang_hooks.callgraph.expand_function)
flag_unit_at_a_time = 0;
------------
In function.c:
/* Possibly warn about unused parameters.
When frontend does unit-at-a-time, the warning is already
issued at finalization time. */
if (warn_unused_parameter
&& !lang_hooks.callgraph.expand_function)
do_warn_unused_parameter (current_function_decl);
------------
We tried setting lang_hooks.callgraph.expand_function to NULL:
/* For now, disable unit-at-a-time by setting expand_function to NULL */
#undef LANG_HOOKS_CALLGRAPH_EXPAND_FUNCTION
#define LANG_HOOKS_CALLGRAPH_EXPAND_FUNCTION NULL
which has the desired effect of disabling unit-at-a-time, but
runs aground in cgraph_expand_function() with a segfault,
when it attempts to call lang_hooks.callgraph.expand_function().
It seems that GCC is handling lang_hooks.callgraph.expand_function
in an inconsistent fashion. Is a null value for expand_function
meaningful? If it is, then what is the fix for cgraph_expand_function()?
----
In a follow-up note on the GCC list, Dueway Qi notes:
I have found another similar case.
lang_hooks.callgraph.analyze_expr in gcc/gcc/cgraphunit.c
490 if (lang_hooks.callgraph.analyze_expr)
491 return lang_hooks.callgraph.analyze_expr (tp,
walk_subtrees,
492 data);
but in another part of this file
517 if ((unsigned int) TREE_CODE (t) >= LAST_AND_UNUSED_TREE_CODE)
518 return lang_hooks.callgraph.analyze_expr (tp,
walk_subtrees, data);
--
Summary: inconsistent handling of null-valued language hooks in
GCC
Product: gcc
Version: 4.0.1
Status: UNCONFIRMED
Severity: normal
Priority: P2
Component: c
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: gary at intrepid dot com
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24539
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c/24539] inconsistent handling of null-valued language hooks in GCC
2005-10-26 14:28 [Bug c/24539] New: inconsistent handling of null-valued language hooks in GCC gary at intrepid dot com
@ 2005-10-26 14:39 ` gary at intrepid dot com
2005-10-26 15:54 ` [Bug middle-end/24539] " pinskia at gcc dot gnu dot org
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: gary at intrepid dot com @ 2005-10-26 14:39 UTC (permalink / raw)
To: gcc-bugs
------- Comment #1 from gary at intrepid dot com 2005-10-26 14:39 -------
*** Bug 24540 has been marked as a duplicate of this bug. ***
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24539
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug middle-end/24539] inconsistent handling of null-valued language hooks in GCC
2005-10-26 14:28 [Bug c/24539] New: inconsistent handling of null-valued language hooks in GCC gary at intrepid dot com
2005-10-26 14:39 ` [Bug c/24539] " gary at intrepid dot com
@ 2005-10-26 15:54 ` pinskia at gcc dot gnu dot org
2005-10-26 16:07 ` gary at intrepid dot com
2005-10-26 16:09 ` pinskia at gcc dot gnu dot org
3 siblings, 0 replies; 5+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2005-10-26 15:54 UTC (permalink / raw)
To: gcc-bugs
------- Comment #2 from pinskia at gcc dot gnu dot org 2005-10-26 15:54 -------
I think analyze_expr should be removed as by the time we get there, we are
always in gimple.
As for expand_function, we really should have a default one now as almost no
language does not support unit at a time.
--
pinskia at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Component|c |middle-end
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24539
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug middle-end/24539] inconsistent handling of null-valued language hooks in GCC
2005-10-26 14:28 [Bug c/24539] New: inconsistent handling of null-valued language hooks in GCC gary at intrepid dot com
2005-10-26 14:39 ` [Bug c/24539] " gary at intrepid dot com
2005-10-26 15:54 ` [Bug middle-end/24539] " pinskia at gcc dot gnu dot org
@ 2005-10-26 16:07 ` gary at intrepid dot com
2005-10-26 16:09 ` pinskia at gcc dot gnu dot org
3 siblings, 0 replies; 5+ messages in thread
From: gary at intrepid dot com @ 2005-10-26 16:07 UTC (permalink / raw)
To: gcc-bugs
------- Comment #3 from gary at intrepid dot com 2005-10-26 16:07 -------
All/most GCC-supplied dialects may support unit-at-a-time, however,
the dialect we're working on (UPC) does not at present support
unit-at-a-time.
For now, we're de-asserting flag_unit_at_a_time in the language
specific post_options routine.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24539
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug middle-end/24539] inconsistent handling of null-valued language hooks in GCC
2005-10-26 14:28 [Bug c/24539] New: inconsistent handling of null-valued language hooks in GCC gary at intrepid dot com
` (2 preceding siblings ...)
2005-10-26 16:07 ` gary at intrepid dot com
@ 2005-10-26 16:09 ` pinskia at gcc dot gnu dot org
3 siblings, 0 replies; 5+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2005-10-26 16:09 UTC (permalink / raw)
To: gcc-bugs
------- Comment #4 from pinskia at gcc dot gnu dot org 2005-10-26 16:09 -------
(In reply to comment #3)
> For now, we're de-asserting flag_unit_at_a_time in the language
> specific post_options routine.
You should note that non unit-at-a-time will be removed in the future so you
may as well just do unit at a time to start with.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24539
^ permalink raw reply [flat|nested] 5+ messages in thread
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2005-10-26 14:28 [Bug c/24539] New: inconsistent handling of null-valued language hooks in GCC gary at intrepid dot com
2005-10-26 14:39 ` [Bug c/24539] " gary at intrepid dot com
2005-10-26 15:54 ` [Bug middle-end/24539] " pinskia at gcc dot gnu dot org
2005-10-26 16:07 ` gary at intrepid dot com
2005-10-26 16:09 ` pinskia at gcc dot gnu dot org
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