Install <sys/platform/x86.h> so that programmers can do
#if __has_include(<sys/platform/x86.h>)
#include <sys/platform/x86.h>
#endif
...
if (CPU_FEATURE_USABLE (SSE2))
...
if (CPU_FEATURE_USABLE (AVX2))
...
<sys/platform/x86.h> exports only:
enum
{
COMMON_CPUID_INDEX_1 = 0,
COMMON_CPUID_INDEX_7,
COMMON_CPUID_INDEX_80000001,
COMMON_CPUID_INDEX_D_ECX_1,
COMMON_CPUID_INDEX_80000007,
COMMON_CPUID_INDEX_80000008,
COMMON_CPUID_INDEX_7_ECX_1,
/* Keep the following line at the end. */
COMMON_CPUID_INDEX_MAX
};
struct cpuid_features
{
struct cpuid_registers cpuid;
struct cpuid_registers usable;
};
struct cpu_features
{
struct cpu_features_basic basic;
struct cpuid_features features[COMMON_CPUID_INDEX_MAX];
};
/* Get a pointer to the CPU features structure. */
extern const struct cpu_features *__x86_get_cpu_features
(unsigned int max) __attribute__ ((const));
Since all feature checks are done through macros, programs compiled with
a newer <sys/platform/x86.h> are compatible with the older glibc binaries
as long as the layout of struct cpu_features is identical. The features
array can be expanded with backward binary compatibility for both .o and
.so files. When COMMON_CPUID_INDEX_MAX is increased to support new
processor features, __x86_get_cpu_features in the older glibc binaries
returns NULL and HAS_CPU_FEATURE/CPU_FEATURE_USABLE return false on the
new processor feature. No new symbol version is neeeded.
Both CPU_FEATURE_USABLE and HAS_CPU_FEATURE are provided. HAS_CPU_FEATURE
can be used to identify processor features.
Note: Although GCC has __builtin_cpu_supports, it only supports a subset
of <sys/platform/x86.h> and it is equivalent to CPU_FEATURE_USABLE. It
doesn't support HAS_CPU_FEATURE.
Merge x86 ifunc-defines.sym with x86 cpu-features-offsets.sym. Remove
x86 ifunc-defines.sym and rtld-global-offsets.sym. No code changes on
i686 and x86-64.
* sysdeps/i386/i686/multiarch/Makefile (gen-as-const-headers):
Remove ifunc-defines.sym.
* sysdeps/x86_64/multiarch/Makefile (gen-as-const-headers):
Likewise.
* sysdeps/i386/i686/multiarch/ifunc-defines.sym: Removed.
* sysdeps/x86/rtld-global-offsets.sym: Likewise.
* sysdeps/x86_64/multiarch/ifunc-defines.sym: Likewise.
* sysdeps/x86/Makefile (gen-as-const-headers): Remove
rtld-global-offsets.sym.
* sysdeps/x86_64/multiarch/ifunc-defines.sym: Merged with ...
* sysdeps/x86/cpu-features-offsets.sym: This.
* sysdeps/x86/cpu-features.h: Include <cpu-features-offsets.h>
instead of <ifunc-defines.h> and <rtld-global-offsets.h>.
GCC added support for -msse4 in version 4.3. Thus the configure tests
for it are obsolete, and this patch removes them.
Tested for x86_64 and x86 (testsuite, and that installed stripped
shared libraries are unchanged by this patch).
* sysdeps/i386/configure.ac (libc_cv_cc_sse4): Remove configure
test.
* sysdeps/i386/configure: Regenerated.
* sysdeps/i386/i686/multiarch/Makefile
[$(config-cflags-sse4) = yes]: Make code unconditional.
* sysdeps/i386/i686/multiarch/strcspn.S [HAVE_SSE4_SUPPORT]:
Likewise.
* sysdeps/i386/i686/multiarch/strspn.S [HAVE_SSE4_SUPPORT]:
Likewise.
* sysdeps/x86_64/configure.ac (libc_cv_cc_sse4): Remove configure
test.
* sysdeps/x86_64/configure: Regenerated.
* sysdeps/x86_64/multiarch/Makefile [$(config-cflags-sse4) = yes]:
Make code unconditional.
* sysdeps/x86_64/multiarch/strcspn.S [HAVE_SSE4_SUPPORT]:
Likewise.
* sysdeps/x86_64/multiarch/strspn.S [HAVE_SSE4_SUPPORT]: Likewise.
* config.h.in (HAVE_SSE4_SUPPORT): Remove #undef.
These new memcpy functions are the 32-bit version of x86_64 SSE2 unaligned
memcpy. Memcpy average performace benefit is 18% on Silvermont, other
platforms also improved about 35%, benchmarked on Silvermont, Haswell, Ivy
Bridge, Sandy Bridge and Westmere, performance results attached in
https://sourceware.org/ml/libc-alpha/2014-07/msg00157.html
* sysdeps/i386/i686/multiarch/bcopy-sse2-unaligned.S: New file.
* sysdeps/i386/i686/multiarch/memcpy-sse2-unaligned.S: Likewise.
* sysdeps/i386/i686/multiarch/memmove-sse2-unaligned.S: Likewise.
* sysdeps/i386/i686/multiarch/mempcpy-sse2-unaligned.S: Likewise.
* sysdeps/i386/i686/multiarch/bcopy.S: Select the sse2_unaligned
version if bit_Fast_Unaligned_Load is set.
* sysdeps/i386/i686/multiarch/memcpy.S: Likewise.
* sysdeps/i386/i686/multiarch/memcpy_chk.S: Likewise.
* sysdeps/i386/i686/multiarch/memmove.S: Likewise.
* sysdeps/i386/i686/multiarch/memmove_chk.S: Likewise.
* sysdeps/i386/i686/multiarch/mempcpy.S: Likewise.
* sysdeps/i386/i686/multiarch/mempcpy_chk.S: Likewise.
* sysdeps/i386/i686/multiarch/Makefile (sysdep_routines): Add
bcopy-sse2-unaligned, memcpy-sse2-unaligned,
memmove-sse2-unaligned and mempcpy-sse2-unaligned.
* sysdeps/i386/i686/multiarch/ifunc-impl-list.c (MAX_IFUNC): Set
to 4.
(__libc_ifunc_impl_list): Test __bcopy_sse2_unaligned,
__memmove_chk_sse2_unaligned, __memmove_sse2_unaligned,
__memcpy_chk_sse2_unaligned, __memcpy_sse2_unaligned,
__mempcpy_chk_sse2_unaligned, and __mempcpy_sse2_unaligned.
This patch adds 32bit SSE4.2 string functions. It uses -16L instead of
0xfffffffffffffff0L, which works for both 32bit and 64bit long. Tested
on 32bit Core i7 and Core 2.
This patch adds multiarch support when configured for i686. I modified
some x86-64 functions to support 32bit. I will contribute 32bit SSE string
and memory functions later.
