Switch to Arm Optimized Routines for mem* & str*

These are the updated version of the older Cortex Strings Library we
previously used. The Arm Optimized Routines also support CPU features
that are currently in development on FreeBSD, e.g. Branch Target
Identification (BTI). Rather than add BTI support to the old code it's
easier to just use the maintained version.

Sponsored by:	The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D32774

lib/libc/aarch64/string/Makefile.inc

@@ -1,20 +1,41 @@
 # $FreeBSD$
 #
-# String handling from the Cortex Strings library
-# https://git.linaro.org/toolchain/cortex-strings.git
+# String handling from the Arm Optimized Routines
+# https://github.com/ARM-software/optimized-routines
 #
 
-.PATH: ${SRCTOP}/contrib/cortex-strings/src/aarch64
+AARCH64_STRING_FUNCS= \
+	memchr \
+	memcmp \
+	memcpy \
+	memmove \
+	memrchr \
+	memset \
+	stpcpy \
+	strchr \
+	strchrnul \
+	strcmp \
+	strcpy \
+	strlen \
+	strncmp \
+	strnlen \
+	strrchr
 
-MDSRCS+= \
-	memchr.S \
-	memcmp.S \
-	memcpy.S \
-	memmove.S \
-	memset.S \
-	strchr.S \
-	strcmp.S \
-	strcpy.S \
-	strlen.S \
-	strncmp.S \
-	strnlen.S
+#
+# Add the above functions. Generate an asm file that includes the needed
+# Arm Optimized Routines file defining the function name to the libc name.
+# Some file need multiple macros defined or a weak symbol added we can
+# override the generated file in these cases.
+#
+.for FUNC in ${AARCH64_STRING_FUNCS}
+.if !exists(${FUNC}.S)
+${FUNC}.S:
+	printf '/* %sgenerated by libc/aarch64/string/Makefile.inc */\n' @ > ${.TARGET}
+	printf '#define	__%s_aarch64 %s\n' ${FUNC} ${FUNC} >> ${.TARGET}
+	printf '#include "aarch64/%s.S"\n' ${FUNC} >> ${.TARGET}
+CLEANFILES+=	${FUNC}.S
+.endif
+
+MDSRCS+=	${FUNC}.S
+CFLAGS.${FUNC}.S+=-I${SRCTOP}/contrib/arm-optimized-routines/string
+.endfor

lib/libc/aarch64/string/memcpy.S

@@ -0,0 +1,6 @@
+#define	__memcpy_aarch64	memcpy
+#define	__memmove_aarch64	memmove
+#include "aarch64/memcpy.S"
+
+.weak index
+.equ index, strchr

lib/libc/aarch64/string/memmove.S

@@ -0,0 +1,5 @@
+/*
+ * memmove is implemented in memcpy.S. Having this file simplifies the build
+ * as it stops MISRCS from picking up the C implementation and rtld expects
+ * to copy the memmove object file into its object directory.
+ */

lib/libc/aarch64/string/strchr.S

@@ -0,0 +1,5 @@
+#define	__strchr_aarch64	strchr
+#include "aarch64/strchr.S"
+
+.weak index
+.equ index, strchr

lib/libc/aarch64/string/strrchr.S

@@ -0,0 +1,5 @@
+#define	__strrchr_aarch64	strrchr
+#include "aarch64/strrchr.S"
+
+.weak rindex
+.equ rindex, strrchr