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* [Bug target/66609] New: [sh] Relative address expressions bind at as-time, even if symbol is weak
@ 2015-06-19 21:11 bugdal at aerifal dot cx
2015-08-23 8:48 ` [Bug target/66609] " kkojima at gcc dot gnu.org
` (9 more replies)
0 siblings, 10 replies; 11+ messages in thread
From: bugdal at aerifal dot cx @ 2015-06-19 21:11 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66609
Bug ID: 66609
Summary: [sh] Relative address expressions bind at as-time,
even if symbol is weak
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: bugdal at aerifal dot cx
Target Milestone: ---
Minimal test case (compile with -fPIC and -Os or higher, for sh2 or later):
__attribute__((__weak__,__visibility__("hidden"))) void foo()
{
}
void bar()
{
foo();
}
For the call from bar to foo, gcc generates:
mov.l .L3,r1
braf r1
.LPCS0:
nop
.align 2
.L3:
.long foo-(.LPCS0+2)
Gas in turn ignores the fact that foo is weak and assembles the literal to a
constant with no relocation. This is the following bug I just reported in
binutils:
https://sourceware.org/bugzilla/show_bug.cgi?id=18561
However, GCC can and probably should work around it, by instead generating the
equivalent form that gas assembles correctly:
.long foo@PCREL-(.LPCS0+2-.)
This is easily changed at the following location:
https://gcc.gnu.org/git/?p=gcc.git;a=blob;f=gcc/config/sh/sh.c;h=e5fcd7683ef7e06d56a10427d792ba018d1af884;hb=HEAD#l1662
and changing it seems to have solved the problem for me, but I did not yet test
extensively. I'm not sure if the subsequent case for UNSPEC_PCREL_SYMOFF also
needs changes.
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug target/66609] [sh] Relative address expressions bind at as-time, even if symbol is weak
2015-06-19 21:11 [Bug target/66609] New: [sh] Relative address expressions bind at as-time, even if symbol is weak bugdal at aerifal dot cx
@ 2015-08-23 8:48 ` kkojima at gcc dot gnu.org
2015-08-24 1:59 ` bugdal at aerifal dot cx
` (8 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: kkojima at gcc dot gnu.org @ 2015-08-23 8:48 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66609
Kazumoto Kojima <kkojima at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |kkojima at gcc dot gnu.org
--- Comment #1 from Kazumoto Kojima <kkojima at gcc dot gnu.org> ---
Created attachment 36246
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=36246&action=edit
patch
> .long foo@PCREL-(.LPCS0+2-.)
looks to be reasonable. It seems that sh backend shouldn't
use UNSPEC_SYMOFF for that case in the first place. Does
the patch attached work for you?
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug target/66609] [sh] Relative address expressions bind at as-time, even if symbol is weak
2015-06-19 21:11 [Bug target/66609] New: [sh] Relative address expressions bind at as-time, even if symbol is weak bugdal at aerifal dot cx
2015-08-23 8:48 ` [Bug target/66609] " kkojima at gcc dot gnu.org
@ 2015-08-24 1:59 ` bugdal at aerifal dot cx
2015-08-24 2:50 ` kkojima at gcc dot gnu.org
` (7 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: bugdal at aerifal dot cx @ 2015-08-24 1:59 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66609
--- Comment #2 from Rich Felker <bugdal at aerifal dot cx> ---
The patch in comment 1 applies successfully to GCC 5.2.0 and fixes both the
test case and the real-world code I was experiencing problems with.
Unfortunately it doesn't apply to some of the older GCC versions I need to
support, but I think I can backport it. Thanks!
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug target/66609] [sh] Relative address expressions bind at as-time, even if symbol is weak
2015-06-19 21:11 [Bug target/66609] New: [sh] Relative address expressions bind at as-time, even if symbol is weak bugdal at aerifal dot cx
2015-08-23 8:48 ` [Bug target/66609] " kkojima at gcc dot gnu.org
2015-08-24 1:59 ` bugdal at aerifal dot cx
@ 2015-08-24 2:50 ` kkojima at gcc dot gnu.org
2015-08-24 23:23 ` kkojima at gcc dot gnu.org
` (6 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: kkojima at gcc dot gnu.org @ 2015-08-24 2:50 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66609
--- Comment #3 from Kazumoto Kojima <kkojima at gcc dot gnu.org> ---
(In reply to Rich Felker from comment #2)
Thanks for the confirmation. I'll commit the patch after the undergoing
additional test done.
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug target/66609] [sh] Relative address expressions bind at as-time, even if symbol is weak
2015-06-19 21:11 [Bug target/66609] New: [sh] Relative address expressions bind at as-time, even if symbol is weak bugdal at aerifal dot cx
` (2 preceding siblings ...)
2015-08-24 2:50 ` kkojima at gcc dot gnu.org
@ 2015-08-24 23:23 ` kkojima at gcc dot gnu.org
2015-09-19 3:39 ` olegendo at gcc dot gnu.org
` (5 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: kkojima at gcc dot gnu.org @ 2015-08-24 23:23 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66609
--- Comment #4 from Kazumoto Kojima <kkojima at gcc dot gnu.org> ---
Author: kkojima
Date: Mon Aug 24 23:23:00 2015
New Revision: 227155
URL: https://gcc.gnu.org/viewcvs?rev=227155&root=gcc&view=rev
Log:
PR target/66609
* [SH] Take into account weak symbols for pc relative calls/sibcalls.
Modified:
trunk/gcc/ChangeLog
trunk/gcc/config/sh/sh-protos.h
trunk/gcc/config/sh/sh.c
trunk/gcc/config/sh/sh.md
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug target/66609] [sh] Relative address expressions bind at as-time, even if symbol is weak
2015-06-19 21:11 [Bug target/66609] New: [sh] Relative address expressions bind at as-time, even if symbol is weak bugdal at aerifal dot cx
` (3 preceding siblings ...)
2015-08-24 23:23 ` kkojima at gcc dot gnu.org
@ 2015-09-19 3:39 ` olegendo at gcc dot gnu.org
2015-09-19 12:52 ` kkojima at gcc dot gnu.org
` (4 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: olegendo at gcc dot gnu.org @ 2015-09-19 3:39 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66609
Oleg Endo <olegendo at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |olegendo at gcc dot gnu.org
--- Comment #5 from Oleg Endo <olegendo at gcc dot gnu.org> ---
Kaz, do you think it's OK to backport this to GCC 5? It looks like the patch
is not so intrusive...
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug target/66609] [sh] Relative address expressions bind at as-time, even if symbol is weak
2015-06-19 21:11 [Bug target/66609] New: [sh] Relative address expressions bind at as-time, even if symbol is weak bugdal at aerifal dot cx
` (4 preceding siblings ...)
2015-09-19 3:39 ` olegendo at gcc dot gnu.org
@ 2015-09-19 12:52 ` kkojima at gcc dot gnu.org
2015-09-21 7:29 ` bugdal at aerifal dot cx
` (3 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: kkojima at gcc dot gnu.org @ 2015-09-19 12:52 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66609
--- Comment #6 from Kazumoto Kojima <kkojima at gcc dot gnu.org> ---
(In reply to Oleg Endo from comment #5)
> Kaz, do you think it's OK to backport this to GCC 5? It looks like the
> patch is not so intrusive...
Changing relocation is always intrusive, I think. I won't
object to backport it, though. The patch does the right thing
and will affect only very limited cases.
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug target/66609] [sh] Relative address expressions bind at as-time, even if symbol is weak
2015-06-19 21:11 [Bug target/66609] New: [sh] Relative address expressions bind at as-time, even if symbol is weak bugdal at aerifal dot cx
` (5 preceding siblings ...)
2015-09-19 12:52 ` kkojima at gcc dot gnu.org
@ 2015-09-21 7:29 ` bugdal at aerifal dot cx
2015-09-21 7:33 ` bugdal at aerifal dot cx
` (2 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: bugdal at aerifal dot cx @ 2015-09-21 7:29 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66609
--- Comment #7 from Rich Felker <bugdal at aerifal dot cx> ---
Created attachment 36359
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=36359&action=edit
preprocessed source still affected by the bug
Oddly I'm still experiencing this bug for some functions but not others, even
with the patch applied. I've attached preprocessed output of a file which is
being miscompiled: the reference to __do_cleanup_push wrongly binds locally,
but the reference to __do_cleanup_pop is overridable like it should be.
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug target/66609] [sh] Relative address expressions bind at as-time, even if symbol is weak
2015-06-19 21:11 [Bug target/66609] New: [sh] Relative address expressions bind at as-time, even if symbol is weak bugdal at aerifal dot cx
` (6 preceding siblings ...)
2015-09-21 7:29 ` bugdal at aerifal dot cx
@ 2015-09-21 7:33 ` bugdal at aerifal dot cx
2015-09-23 18:10 ` bugdal at aerifal dot cx
2015-10-26 12:24 ` olegendo at gcc dot gnu.org
9 siblings, 0 replies; 11+ messages in thread
From: bugdal at aerifal dot cx @ 2015-09-21 7:33 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66609
--- Comment #8 from Rich Felker <bugdal at aerifal dot cx> ---
Perhaps hold off on worrying about this; it's only happening with -mfdpic (with
my forward-port of the fdpic patch applied) so it's possible that the bug is on
my end in code that's not in upstream gcc. I'll follow up on this more later.
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug target/66609] [sh] Relative address expressions bind at as-time, even if symbol is weak
2015-06-19 21:11 [Bug target/66609] New: [sh] Relative address expressions bind at as-time, even if symbol is weak bugdal at aerifal dot cx
` (7 preceding siblings ...)
2015-09-21 7:33 ` bugdal at aerifal dot cx
@ 2015-09-23 18:10 ` bugdal at aerifal dot cx
2015-10-26 12:24 ` olegendo at gcc dot gnu.org
9 siblings, 0 replies; 11+ messages in thread
From: bugdal at aerifal dot cx @ 2015-09-23 18:10 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66609
--- Comment #9 from Rich Felker <bugdal at aerifal dot cx> ---
Indeed, the fdpic patch I forward-ported introduced new duplicates of some of
the fragments that were changed in sh.md by the above patch. Once I fixed
those, the problem went away. Sorry for the noise.
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug target/66609] [sh] Relative address expressions bind at as-time, even if symbol is weak
2015-06-19 21:11 [Bug target/66609] New: [sh] Relative address expressions bind at as-time, even if symbol is weak bugdal at aerifal dot cx
` (8 preceding siblings ...)
2015-09-23 18:10 ` bugdal at aerifal dot cx
@ 2015-10-26 12:24 ` olegendo at gcc dot gnu.org
9 siblings, 0 replies; 11+ messages in thread
From: olegendo at gcc dot gnu.org @ 2015-10-26 12:24 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66609
Oleg Endo <olegendo at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Resolution|--- |FIXED
--- Comment #10 from Oleg Endo <olegendo at gcc dot gnu.org> ---
I think we can close this as fixed.
^ permalink raw reply [flat|nested] 11+ messages in thread
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2015-08-23 8:48 ` [Bug target/66609] " kkojima at gcc dot gnu.org
2015-08-24 1:59 ` bugdal at aerifal dot cx
2015-08-24 2:50 ` kkojima at gcc dot gnu.org
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