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From 7dfe8a35215a019f552f117d907eca294225c121 Mon Sep 17 00:00:00 2001
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From: Adhemerval Zanella <azanella@linux.vnet.ibm.com>
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Date: Wed, 12 Jun 2013 10:21:22 -0500
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Subject: [PATCH 35/42] Fix unsafe compiler optimization
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GCC 4.8 enables -ftree-loop-distribute-patterns at -O3 by default and
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this optimization may transform loops into memset/memmove calls. Without
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proper handling this may generate unexpected PLT calls on GLIBC.
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This patch fixes by create memset/memmove alias to internal GLIBC
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__GI_memset/__GI_memmove symbols.
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(cherry picked from commit 6a97b62a5b4f18aea849d6f4d8de58d1469d2521)
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---
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sysdeps/generic/symbol-hacks.h | 7 ++++++-
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sysdeps/wordsize-32/symbol-hacks.h | 2 ++
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3 files changed, 16 insertions(+), 1 deletion(-)
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diff --git a/sysdeps/generic/symbol-hacks.h b/sysdeps/generic/symbol-hacks.h
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index bc7b4c4..9eaf014 100644
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--- a/sysdeps/generic/symbol-hacks.h
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+++ b/sysdeps/generic/symbol-hacks.h
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@@ -1 +1,6 @@
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-/* Fortunately nothing to do. */
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+/* Some compiler optimizations may transform loops into memset/memmove
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+ calls and without proper declaration it may generate PLT calls. */
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+#if !defined __ASSEMBLER__ && !defined NOT_IN_libc && defined SHARED
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+asm ("memmove = __GI_memmove");
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+asm ("memset = __GI_memset");
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+#endif
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diff --git a/sysdeps/wordsize-32/symbol-hacks.h b/sysdeps/wordsize-32/symbol-hacks.h
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index 52a14fc..ad5b231 100644
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--- a/sysdeps/wordsize-32/symbol-hacks.h
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+++ b/sysdeps/wordsize-32/symbol-hacks.h
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@@ -16,6 +16,8 @@
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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+#include_next "symbol-hacks.h"
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+
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/* A very dirty trick: gcc emits references to __divdi3, __udivdi3,
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__moddi3, and __umoddi3. These functions are exported and
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therefore we get PLTs. Unnecessarily so. Changing gcc is a big
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--
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1.7.11.7
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