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| author | Adhemerval Zanella <azanella@linux.vnet.ibm.com> | 2013-06-12 10:21:22 -0500 |
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| committer | Adhemerval Zanella <azanella@linux.vnet.ibm.com> | 2013-06-12 10:21:22 -0500 |
| commit | 6a97b62a5b4f18aea849d6f4d8de58d1469d2521 (patch) | |
| tree | 0fdb35cb468bdb040fd3a1f01b4ddcc70b0f30dd | |
| parent | 94f2c076692a5a4beaa9a85eb10dbe4d891acb1e (diff) | |
| download | glibc-6a97b62a5b4f18aea849d6f4d8de58d1469d2521.tar glibc-6a97b62a5b4f18aea849d6f4d8de58d1469d2521.tar.gz glibc-6a97b62a5b4f18aea849d6f4d8de58d1469d2521.tar.bz2 glibc-6a97b62a5b4f18aea849d6f4d8de58d1469d2521.zip | |
Fix unsafe compiler optimization
GCC 4.8 enables -ftree-loop-distribute-patterns at -O3 by default and
this optimization may transform loops into memset/memmove calls. Without
proper handling this may generate unexpected PLT calls on GLIBC.
This patch fixes by create memset/memmove alias to internal GLIBC
__GI_memset/__GI_memmove symbols.
| -rw-r--r-- | ChangeLog | 8 | ||||
| -rw-r--r-- | sysdeps/generic/symbol-hacks.h | 7 | ||||
| -rw-r--r-- | sysdeps/wordsize-32/symbol-hacks.h | 2 |
3 files changed, 16 insertions, 1 deletions
@@ -1,3 +1,11 @@ +2013-06-11 Adhemerval Zanella <azanella@linux.vnet.ibm.com> + + [BZ #15605] + * sysdeps/generic/symbol-hacks.h: Add workaround for memset/memmove calls + generated by the compiler on loop optimizations. + * sysdeps/wordsize-32/symbol-hacks.h: Include next symbol-hacks.h for + general definitions. + 2013-06-12 Joseph Myers <joseph@codesourcery.com> * math/bug-nextafter.c: Include <math-tests.h>. diff --git a/sysdeps/generic/symbol-hacks.h b/sysdeps/generic/symbol-hacks.h index bc7b4c4441..9eaf014ff2 100644 --- a/sysdeps/generic/symbol-hacks.h +++ b/sysdeps/generic/symbol-hacks.h @@ -1 +1,6 @@ -/* Fortunately nothing to do. */ +/* Some compiler optimizations may transform loops into memset/memmove + calls and without proper declaration it may generate PLT calls. */ +#if !defined __ASSEMBLER__ && !defined NOT_IN_libc && defined SHARED +asm ("memmove = __GI_memmove"); +asm ("memset = __GI_memset"); +#endif diff --git a/sysdeps/wordsize-32/symbol-hacks.h b/sysdeps/wordsize-32/symbol-hacks.h index 52ac5c1e0a..202a8070de 100644 --- a/sysdeps/wordsize-32/symbol-hacks.h +++ b/sysdeps/wordsize-32/symbol-hacks.h @@ -16,6 +16,8 @@ License along with the GNU C Library; if not, see <http://www.gnu.org/licenses/>. */ +#include_next "symbol-hacks.h" + /* A very dirty trick: gcc emits references to __divdi3, __udivdi3, __moddi3, and __umoddi3. These functions are exported and therefore we get PLTs. Unnecessarily so. Changing gcc is a big |