x86-64: Implement strcmp family IFUNC selectors in C

Implement strcmp 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 strcmp family functions within libc.

	* sysdeps/x86_64/multiarch/Makefile (sysdep_routines): Add
	strcmp-sse2, strcmp-sse4_2, strncmp-sse2, strncmp-sse4_2,
	strcasecmp_l-sse2, strcasecmp_l-sse4_2, strcasecmp_l-avx,
	strncase_l-sse2, strncase_l-sse4_2 and strncase_l-avx.
	* sysdeps/x86_64/multiarch/ifunc-strcasecmp.h: New file.
	* sysdeps/x86_64/multiarch/strcasecmp.c: Likewise.
	* sysdeps/x86_64/multiarch/strcasecmp_l-avx.S: Likewise.
	* sysdeps/x86_64/multiarch/strcasecmp_l-sse2.S: Likewise.
	* sysdeps/x86_64/multiarch/strcasecmp_l-sse4_2.S: Likewise.
	* sysdeps/x86_64/multiarch/strcasecmp_l.c: Likewise.
	* sysdeps/x86_64/multiarch/strcmp-sse2.S: Likewise.
	* sysdeps/x86_64/multiarch/strcmp-sse4_2.S: Likewise.
	* sysdeps/x86_64/multiarch/strcmp.c: Likewise.
	* sysdeps/x86_64/multiarch/strncase.c: Likewise.
	* sysdeps/x86_64/multiarch/strncase_l-avx.S : Likewise.
	* sysdeps/x86_64/multiarch/strncase_l-sse2.S: Likewise.
	* sysdeps/x86_64/multiarch/strncase_l-sse4_2.S: Likewise.
	* sysdeps/x86_64/multiarch/strncase_l.c: Likewise.
	* sysdeps/x86_64/multiarch/strncmp-sse2.S: Likewise.
	* sysdeps/x86_64/multiarch/strncmp-sse4_2.S: Likewise.
	* sysdeps/x86_64/multiarch/strncmp.c: Likewise.
	* sysdeps/x86_64/multiarch/strcasecmp_l.S: Removed.
	* sysdeps/x86_64/multiarch/strcmp.S: Likewise.
	* sysdeps/x86_64/multiarch/strncase_l.S: Likewise.
	* sysdeps/x86_64/multiarch/strncmp.S: Likewise.
	* sysdeps/x86_64/multiarch/strcmp-sse42.S: Include <sysdep.h>.
	(STRCMP_SSE42): New.  Defined to __strcmp_sse42 if not defined.
	[USE_AS_STRCASECMP_L || USE_AS_STRNCASECMP_L]: Include
	"locale-defines.h".
	(UPDATE_STRNCMP_COUNTER): New.
	(SECTION): Likewise.
	(GLABEL): Likewise.
	(LABEL): Likewise.
	* sysdeps/x86_64/multiarch/strncmp-ssse3.S: Rewrite and enable
	for libc.a.

1 files changed, 10 insertions, 4 deletions

diff --git a/sysdeps/x86_64/multiarch/Makefile b/sysdeps/x86_64/multiarch/Makefile
index 2c54c5cc23..68257c4017 100644
--- a/sysdeps/x86_64/multiarch/Makefile
+++ b/sysdeps/x86_64/multiarch/Makefile
@@ -4,8 +4,10 @@ endif
 
 ifeq ($(subdir),string)
 
-sysdep_routines += strncat-c stpncpy-c strncpy-c strcmp-ssse3 \
-		   strcmp-sse2-unaligned strncmp-ssse3 \
+sysdep_routines += strncat-c stpncpy-c strncpy-c \
+		   strcmp-sse2 strcmp-sse2-unaligned strcmp-ssse3  \
+		   strcmp-sse4_2 \
+		   strncmp-sse2 strncmp-ssse3 strncmp-sse4_2 \
 		   memchr-sse2 rawmemchr-sse2 memchr-avx2 rawmemchr-avx2 \
 		   memrchr-sse2 memrchr-avx2 \
 		   memcmp-sse2 \
@@ -14,11 +16,15 @@ sysdep_routines += strncat-c stpncpy-c strncpy-c strcmp-ssse3 \
 		   memmove-ssse3 \
 		   memcpy-ssse3-back \
 		   memmove-ssse3-back \
-		   memmove-avx512-no-vzeroupper strcasecmp_l-ssse3 \
+		   memmove-avx512-no-vzeroupper \
+		   strcasecmp_l-sse2 strcasecmp_l-ssse3 \
+		   strcasecmp_l-sse4_2 strcasecmp_l-avx \
+		   strncase_l-sse2 strncase_l-ssse3 \
+		   strncase_l-sse4_2 strncase_l-avx \
 		   strchr-sse2 strchrnul-sse2 strchr-avx2 strchrnul-avx2 \
 		   strrchr-sse2 strrchr-avx2 \
 		   strlen-sse2 strnlen-sse2 strlen-avx2 strnlen-avx2 \
-		   strncase_l-ssse3 strcat-ssse3 strncat-ssse3\
+		   strcat-ssse3 strncat-ssse3\
 		   strcpy-sse2 stpcpy-sse2 \
 		   strcpy-ssse3 strncpy-ssse3 stpcpy-ssse3 stpncpy-ssse3 \
 		   strcpy-sse2-unaligned strncpy-sse2-unaligned \