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x86-64: Implement memcmp family IFUNC selectors in C
Implement memcmp family IFUNC selectors in C. All internal calls within libc.so can use IFUNC on x86-64 since unlike x86, x86-64 supports PC-relative addressing to access the GOT entry so that it can call via PLT without using an extra register. For libc.a, we can't use IFUNC for functions which are called before IFUNC has been initialized. Use IFUNC internally reduces the icache footprint since libc.so and other codes in the process use the same implementations. This patch uses IFUNC for memcmp family functions within libc. * sysdeps/x86_64/multiarch/Makefile (sysdep_routines): Add memcmp-sse2. * sysdeps/x86_64/multiarch/ifunc-memcmp.h: New file. * sysdeps/x86_64/multiarch/memcmp-sse2.S: Likewise. * sysdeps/x86_64/multiarch/memcmp.c: Likewise. * sysdeps/x86_64/multiarch/wmemcmp.c: Likewise. * sysdeps/x86_64/multiarch/memcmp.S: Removed. * sysdeps/x86_64/multiarch/wmemcmp.S: Likewise.
This commit is contained in:
H.J. Lu
parent
93e46f8773
commit
b91a52d0d7
12
ChangeLog
12
ChangeLog
@ -1,3 +1,15 @@
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2017-06-15 H.J. Lu <hongjiu.lu@intel.com>
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Erich Elsen <eriche@google.com>
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* sysdeps/x86_64/multiarch/Makefile (sysdep_routines): Add
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memcmp-sse2.
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* sysdeps/x86_64/multiarch/ifunc-memcmp.h: New file.
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* sysdeps/x86_64/multiarch/memcmp-sse2.S: Likewise.
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* sysdeps/x86_64/multiarch/memcmp.c: Likewise.
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* sysdeps/x86_64/multiarch/wmemcmp.c: Likewise.
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* sysdeps/x86_64/multiarch/memcmp.S: Removed.
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* sysdeps/x86_64/multiarch/wmemcmp.S: Likewise.
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2017-06-15 H.J. Lu <hongjiu.lu@intel.com>
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Erich Elsen <eriche@google.com>
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@ -8,6 +8,7 @@ sysdep_routines += strncat-c stpncpy-c strncpy-c strcmp-ssse3 \
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strcmp-sse2-unaligned strncmp-ssse3 \
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memchr-sse2 rawmemchr-sse2 memchr-avx2 rawmemchr-avx2 \
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memrchr-sse2 memrchr-avx2 \
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memcmp-sse2 \
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memcmp-avx2-movbe \
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memcmp-sse4 memcpy-ssse3 \
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memmove-ssse3 \
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@ -45,7 +45,7 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
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__memchr_avx2)
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IFUNC_IMPL_ADD (array, i, memchr, 1, __memchr_sse2))
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/* Support sysdeps/x86_64/multiarch/memcmp.S. */
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/* Support sysdeps/x86_64/multiarch/memcmp.c. */
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IFUNC_IMPL (i, name, memcmp,
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IFUNC_IMPL_ADD (array, i, memcmp,
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(HAS_ARCH_FEATURE (AVX2_Usable)
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@ -390,7 +390,7 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
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__wmemchr_avx2)
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IFUNC_IMPL_ADD (array, i, wmemchr, 1, __wmemchr_sse2))
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/* Support sysdeps/x86_64/multiarch/wmemcmp.S. */
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/* Support sysdeps/x86_64/multiarch/wmemcmp.c. */
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IFUNC_IMPL (i, name, wmemcmp,
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IFUNC_IMPL_ADD (array, i, wmemcmp,
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(HAS_ARCH_FEATURE (AVX2_Usable)
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45
sysdeps/x86_64/multiarch/ifunc-memcmp.h
Normal file
45
sysdeps/x86_64/multiarch/ifunc-memcmp.h
Normal file
@ -0,0 +1,45 @@
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/* Common definition for memcmp/wmemcmp ifunc selections.
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All versions must be listed in ifunc-impl-list.c.
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Copyright (C) 2017 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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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 <init-arch.h>
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extern __typeof (REDIRECT_NAME) OPTIMIZE (sse2) attribute_hidden;
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extern __typeof (REDIRECT_NAME) OPTIMIZE (ssse3) attribute_hidden;
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extern __typeof (REDIRECT_NAME) OPTIMIZE (sse4_1) attribute_hidden;
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extern __typeof (REDIRECT_NAME) OPTIMIZE (avx2_movbe) attribute_hidden;
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static inline void *
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IFUNC_SELECTOR (void)
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{
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const struct cpu_features* cpu_features = __get_cpu_features ();
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if (!CPU_FEATURES_ARCH_P (cpu_features, Prefer_No_VZEROUPPER)
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&& CPU_FEATURES_ARCH_P (cpu_features, AVX2_Usable)
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&& CPU_FEATURES_CPU_P (cpu_features, MOVBE)
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&& CPU_FEATURES_ARCH_P (cpu_features, AVX_Fast_Unaligned_Load))
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return OPTIMIZE (avx2_movbe);
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if (CPU_FEATURES_CPU_P (cpu_features, SSE4_1))
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return OPTIMIZE (sse4_1);
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if (CPU_FEATURES_CPU_P (cpu_features, SSSE3))
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return OPTIMIZE (ssse3);
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return OPTIMIZE (sse2);
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}
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31
sysdeps/x86_64/multiarch/memcmp-sse2.S
Normal file
31
sysdeps/x86_64/multiarch/memcmp-sse2.S
Normal file
@ -0,0 +1,31 @@
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/* memcmp with SSE2.
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Copyright (C) 2017 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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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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#if IS_IN (libc)
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# define memcmp __memcmp_sse2
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# ifdef SHARED
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# undef libc_hidden_builtin_def
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# define libc_hidden_builtin_def(name)
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# endif
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# undef weak_alias
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# define weak_alias(ignored1, ignored2)
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#endif
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#include <sysdeps/x86_64/memcmp.S>
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@ -1,78 +0,0 @@
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/* Multiple versions of memcmp
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All versions must be listed in ifunc-impl-list.c.
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Copyright (C) 2010-2017 Free Software Foundation, Inc.
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Contributed by Intel Corporation.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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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 <sysdep.h>
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#include <init-arch.h>
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/* Define multiple versions only for the definition in libc. */
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#if IS_IN (libc)
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.text
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ENTRY(memcmp)
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.type memcmp, @gnu_indirect_function
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LOAD_RTLD_GLOBAL_RO_RDX
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HAS_ARCH_FEATURE (Prefer_No_VZEROUPPER)
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jnz 1f
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HAS_ARCH_FEATURE (AVX2_Usable)
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jz 1f
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HAS_CPU_FEATURE (MOVBE)
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jz 1f
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HAS_ARCH_FEATURE (AVX_Fast_Unaligned_Load)
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jz 1f
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leaq __memcmp_avx2_movbe(%rip), %rax
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ret
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1: HAS_CPU_FEATURE (SSSE3)
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jnz 2f
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leaq __memcmp_sse2(%rip), %rax
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ret
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2: HAS_CPU_FEATURE (SSE4_1)
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jz 3f
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leaq __memcmp_sse4_1(%rip), %rax
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ret
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3: leaq __memcmp_ssse3(%rip), %rax
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ret
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END(memcmp)
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# undef ENTRY
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# define ENTRY(name) \
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.type __memcmp_sse2, @function; \
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.p2align 4; \
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.globl __memcmp_sse2; \
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.hidden __memcmp_sse2; \
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__memcmp_sse2: cfi_startproc; \
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CALL_MCOUNT
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# undef END
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# define END(name) \
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cfi_endproc; .size __memcmp_sse2, .-__memcmp_sse2
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# ifdef SHARED
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# undef libc_hidden_builtin_def
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/* It doesn't make sense to send libc-internal memcmp calls through a PLT.
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The speedup we get from using SSE4 instructions is likely eaten away
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by the indirect call in the PLT. */
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# define libc_hidden_builtin_def(name) \
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.globl __GI_memcmp; __GI_memcmp = __memcmp_sse2
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# endif
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#endif
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#include "../memcmp.S"
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38
sysdeps/x86_64/multiarch/memcmp.c
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38
sysdeps/x86_64/multiarch/memcmp.c
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@ -0,0 +1,38 @@
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/* Multiple versions of memcmp.
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All versions must be listed in ifunc-impl-list.c.
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Copyright (C) 2017 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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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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/* Define multiple versions only for the definition in lib and for
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DSO. */
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#if IS_IN (libc)
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# define memcmp __redirect_memcmp
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# include <string.h>
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# undef memcmp
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# define SYMBOL_NAME memcmp
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# include "ifunc-memcmp.h"
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libc_ifunc_redirected (__redirect_memcmp, memcmp, IFUNC_SELECTOR ());
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# undef bcmp
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weak_alias (memcmp, bcmp)
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# ifdef SHARED
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__hidden_ver1 (memcmp, __GI_memcmp, __redirect_memcmp)
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__attribute__ ((visibility ("hidden")));
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# endif
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#endif
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@ -1,7 +1,6 @@
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/* Multiple versions of wmemcmp
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All versions must be listed in ifunc-impl-list.c.
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Copyright (C) 2011-2017 Free Software Foundation, Inc.
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Contributed by Intel Corporation.
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Copyright (C) 2017 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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@ -18,38 +17,15 @@
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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 <sysdep.h>
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#include <init-arch.h>
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/* Define multiple versions only for the definition in libc. */
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/* Define multiple versions only for the definition in lib and for
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DSO. */
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#if IS_IN (libc)
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.text
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ENTRY(wmemcmp)
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.type wmemcmp, @gnu_indirect_function
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LOAD_RTLD_GLOBAL_RO_RDX
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HAS_ARCH_FEATURE (Prefer_No_VZEROUPPER)
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jnz 1f
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HAS_ARCH_FEATURE (AVX2_Usable)
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jz 1f
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HAS_CPU_FEATURE (MOVBE)
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jz 1f
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HAS_ARCH_FEATURE (AVX_Fast_Unaligned_Load)
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jz 1f
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leaq __wmemcmp_avx2_movbe(%rip), %rax
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ret
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# define wmemcmp __redirect_wmemcmp
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# include <wchar.h>
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# undef wmemcmp
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1: HAS_CPU_FEATURE (SSSE3)
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jnz 2f
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leaq __wmemcmp_sse2(%rip), %rax
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ret
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# define SYMBOL_NAME wmemcmp
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# include "ifunc-memcmp.h"
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2: HAS_CPU_FEATURE (SSE4_1)
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jz 3f
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leaq __wmemcmp_sse4_1(%rip), %rax
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ret
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3: leaq __wmemcmp_ssse3(%rip), %rax
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ret
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END(wmemcmp)
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libc_ifunc_redirected (__redirect_wmemcmp, wmemcmp, IFUNC_SELECTOR ());
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#endif
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