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* [Bug c/66784] New: no symbol emitted for builtin with lto
@ 2015-07-07 0:48 guido.hatzsis at yandex dot com
2015-07-07 8:11 ` [Bug lto/66784] " rguenth at gcc dot gnu.org
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: guido.hatzsis at yandex dot com @ 2015-07-07 0:48 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66784
Bug ID: 66784
Summary: no symbol emitted for builtin with lto
Product: gcc
Version: lto
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: guido.hatzsis at yandex dot com
Target Milestone: ---
No symbols are emitted when compiling a built-in with -flto.
eg:
# cat << __EOF > bar.i
_Complex float __mulsc3(float x, float y, float z, float a) { return -1.0; }
__EOF
# rm bar.o ; gcc -c bar.i ; gcc-nm bar.o
0000000000000000 T __mulsc3
# rm bar.o ; gcc -flto -c bar.i ; gcc-nm bar.o
/usr/lib/gcc/x86_64-pc-linux-gnu/5.1.0/../../../../x86_64-pc-linux-gnu/bin/nm:
bar.o: no symbols
# cat << __EOF > bar.i
void __mulsc3(float x, float y, float z, float a) { }
__EOF
# rm bar.o ; gcc -flto -c bar.i ; gcc-nm bar.o
bar.i:1:6: warning: conflicting types for built-in function ‘__mulsc3’
void __mulsc3(float x, float y, float z, float a) { }
^
00000000 T __mulsc3
>From gcc-bugs-return-491613-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org Tue Jul 07 01:22:37 2015
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From: "kkojima at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/66780] [4.9 Regression] Compiling with -fstack-protector-strong causes binary to segfault
Date: Tue, 07 Jul 2015 01:22:00 -0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?idf780
--- Comment #1 from Kazumoto Kojima <kkojima at gcc dot gnu.org> ---
I can reproduce the issue with the trunk cross compiler.
It seems that openproc function in proc/readproc.c is miscompiled
with -fstack-protector-strong. Here is a reduced test case:
--
int t;
struct s {};
int bar (void);
int baz (int, struct s *);
int
foo (int x)
{
struct s sbuf;
static int d;
int val = bar ();
if (d)
{
t = baz (x, &sbuf);
d = 1;
}
return val;
}
--
It turned out that the fix for PR65249 causes this problem.
The codes for stack protect can be inserted after some function
call returning a value. That return value in R0 register could
be clobbered with the fix for PR65249.
I thought that stack_chk_guard thingy is inserted at the head
of the function. It's not the case, unfortunately.
I think that the wrong code is worse than the ICE. I'd like
to revert the patches of PR65249 and reopen that PR.
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2021-12-24 8:20 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2015-07-07 0:48 [Bug c/66784] New: no symbol emitted for builtin with lto guido.hatzsis at yandex dot com
2015-07-07 8:11 ` [Bug lto/66784] " rguenth at gcc dot gnu.org
2015-08-04 8:27 ` guido.hatzsis at yandex dot com
2021-12-24 8:20 ` pinskia at gcc dot gnu.org
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