string:use builtin function to optimize libc function

This allows the compiler to automatically identify which string functions
can be compiled into libraries, and the compiler's internal implementation
is faster than libc functions.

Signed-off-by: anjiahao <anjiahao@xiaomi.com>

include/nuttx/compiler.h

@@ -135,6 +135,13 @@
                                  extern __inline__ no_builtin(#fn) \
                                  __attribute__((__always_inline__, \
                                                 __gnu_inline__, __artificial__))
+#  elif defined(__OPTIMIZE__) && __OPTIMIZE__ > 0 && defined(__has_builtin)
+#    define builtin_original(fn)  __typeof__(fn)  __orig_##fn __asm__(#fn)
+#    define builtin_function(fn)  builtin_original(fn); \
+                                  extern __inline__ no_builtin(#fn) \
+                                  __attribute__((__always_inline__, \
+                                                 __gnu_inline__, __artificial__))
+#    define CONFIG_HAVE_BUILTIN 1 /* Use built-in functions */
 #  endif
 
 /* Pre-processor */

include/string.h

@@ -219,6 +219,232 @@ fortify_function(explicit_bzero) void explicit_bzero(FAR void *s,
 }
 #endif
 
+#ifdef CONFIG_HAVE_BUILTIN
+#  if __has_builtin(__builtin_memcpy)
+builtin_function(memcpy) FAR void *memcpy(FAR void *dest,
+                                          FAR const void *src, size_t n)
+{
+  if (__builtin_constant_p(n))
+    {
+      return __builtin_memcpy(dest, src, n);
+    }
+  else
+    {
+      return __orig_memcpy(dest, src, n);
+    }
+}
+#  endif
+
+#  if __has_builtin(__builtin_memset)
+builtin_function(memset) FAR void *memset(FAR void *s, int c, size_t n)
+{
+  if (__builtin_constant_p(n))
+    {
+      return __builtin_memset(s, c, n);
+    }
+  else
+    {
+      return __orig_memset(s, c, n);
+    }
+}
+#  endif
+
+#  if __has_builtin(__builtin_memcmp)
+builtin_function(memcmp) int memcmp(FAR const void *s1,
+                                    FAR const void *s2, size_t n)
+{
+  if (__builtin_constant_p(s1) && __builtin_constant_p(s2))
+    {
+      return __builtin_memcmp(s1, s2, n);
+    }
+  else
+    {
+      return __orig_memcmp(s1, s2, n);
+    }
+}
+#  endif
+
+#  if __has_builtin(__builtin_memchr)
+builtin_function(memchr) FAR void *memchr(FAR const void *s,
+                                          int c, size_t n)
+{
+  if (__builtin_constant_p(s))
+    {
+      return __builtin_memchr(s, c, n);
+    }
+  else
+    {
+      return __orig_memchr(s, c, n);
+    }
+}
+#  endif
+
+#  if __has_builtin(__builtin_strcat)
+builtin_function(strcat) FAR char *strcat(FAR char *dest,
+                                          FAR const char *src)
+{
+  if (__builtin_constant_p(src))
+    {
+      return __builtin_strcat(dest, src);
+    }
+  else
+    {
+      return __orig_strcat(dest, src);
+    }
+}
+#  endif
+
+#  if __has_builtin(__builtin_strchr)
+builtin_function(strchr) FAR char *strchr(FAR const char *s, int c)
+{
+  if (__builtin_constant_p(s))
+    {
+      return __builtin_strchr(s, c);
+    }
+  else
+    {
+      return __orig_strchr(s, c);
+    }
+}
+#  endif
+
+#  if __has_builtin(__builtin_strcmp)
+builtin_function(strcmp) int strcmp(FAR const char *s1,
+                                    FAR const char *s2)
+{
+  if (__builtin_constant_p(s1) && __builtin_constant_p(s2))
+    {
+      return __builtin_strcmp(s1, s2);
+    }
+  else
+    {
+      return __orig_strcmp(s1, s2);
+    }
+}
+#  endif
+
+#  if __has_builtin(__builtin_strcpy)
+builtin_function(strcpy) FAR char *strcpy(FAR char *dest,
+                                          FAR const char *src)
+{
+  if (__builtin_constant_p(src))
+    {
+      return __builtin_strcpy(dest, src);
+    }
+  else
+    {
+      return __orig_strcpy(dest, src);
+    }
+}
+#  endif
+
+#  if __has_builtin(__builtin_strcspn)
+builtin_function(strcspn) size_t strcspn(FAR const char *s,
+                                         FAR const char *reject)
+{
+  if (__builtin_constant_p(s) && __builtin_constant_p(reject))
+    {
+      return __builtin_strcspn(s, reject);
+    }
+  else
+    {
+      return __orig_strcspn(s, reject);
+    }
+}
+#  endif
+
+#  if __has_builtin(__builtin_strlen)
+builtin_function(strlen) size_t strlen(FAR const char *s)
+{
+  if (__builtin_constant_p(s))
+    {
+      return __builtin_strlen(s);
+    }
+  else
+    {
+      return __orig_strlen(s);
+    }
+}
+#  endif
+
+#  if __has_builtin(__builtin_strncat)
+builtin_function(strncat) FAR char *strncat(FAR char *dest,
+                                            FAR const char *src,
+                                            size_t n)
+{
+  if (__builtin_constant_p(dest))
+    {
+      return __builtin_strncat(dest, src, n);
+    }
+  else
+    {
+      return __orig_strncat(dest, src, n);
+    }
+}
+#  endif
+
+#  if __has_builtin(__builtin_strncmp)
+builtin_function(strncmp) int strncmp(FAR const char *s1,
+                                      FAR const char *s2, size_t n)
+{
+  if (__builtin_constant_p(s1) && __builtin_constant_p(s2))
+    {
+      return __builtin_strncmp(s1, s2, n);
+    }
+  else
+    {
+      return __orig_strncmp(s1, s2, n);
+    }
+}
+#  endif
+
+#  if __has_builtin(__builtin_strncpy)
+builtin_function(strncpy) FAR char *strncpy(FAR char *dest,
+                                            FAR const char *src,
+                                            size_t n)
+{
+  if (__builtin_constant_p(src))
+    {
+      return __builtin_strncpy(dest, src, n);
+    }
+  else
+    {
+      return __orig_strncpy(dest, src, n);
+    }
+}
+#  endif
+
+#  if __has_builtin(__builtin_strpbrk)
+builtin_function(strpbrk) FAR char *strpbrk(FAR const char *s1,
+                                            FAR const char *s2)
+{
+  if (__builtin_constant_p(s1))
+    {
+      return __builtin_strpbrk(s1, s2);
+    }
+  else
+    {
+      return __orig_strpbrk(s1, s2);
+    }
+}
+#  endif
+
+#  if __has_builtin(__builtin_strrchr)
+builtin_function(strrchr) FAR char *strrchr(FAR const char *s,
+                                            int c)
+{
+  if (__builtin_constant_p(s))
+    {
+      return __builtin_strrchr(s, c);
+    }
+  else
+    {
+      return __orig_strrchr(s, c);
+    }
+}
+#  endif
+#endif
+
 #undef EXTERN
 #if defined(__cplusplus)
 }

libs/libc/machine/arch_libc.c

@@ -103,7 +103,8 @@ extern void __asan_storeN(FAR void *addr, size_t size);
  ****************************************************************************/
 
 #ifdef CONFIG_LIBC_ARCH_MEMCHR
-
+#undef memchr
+no_builtin("memchr")
 FAR void *memchr(FAR const void *s, int c, size_t n)
 {
 #  ifdef CONFIG_MM_KASAN_INSTRUMENT
@@ -117,6 +118,8 @@ FAR void *memchr(FAR const void *s, int c, size_t n)
 #endif
 
 #ifdef CONFIG_LIBC_ARCH_MEMCPY
+#undef memcpy
+no_builtin("memcpy")
 FAR void *memcpy(FAR void *dest, FAR const void *src, FAR size_t n)
 {
 #  ifdef CONFIG_MM_KASAN_INSTRUMENT
@@ -132,6 +135,8 @@ FAR void *memcpy(FAR void *dest, FAR const void *src, FAR size_t n)
 #endif
 
 #ifdef CONFIG_LIBC_ARCH_MEMCMP
+#undef memcmp
+no_builtin("memcmp")
 int memcmp(FAR const void *s1, FAR const void *s2, size_t n)
 {
 #  ifdef CONFIG_MM_KASAN_INSTRUMENT
@@ -160,6 +165,8 @@ FAR void *memmove(FAR void *dest, FAR const void *src, FAR size_t n)
 #endif
 
 #ifdef CONFIG_LIBC_ARCH_MEMSET
+#undef memset
+no_builtin("memset")
 FAR void *memset(FAR void *s, int c, FAR size_t n)
 {
 #  ifdef CONFIG_MM_KASAN_INSTRUMENT
@@ -172,6 +179,8 @@ FAR void *memset(FAR void *s, int c, FAR size_t n)
 #endif
 
 #ifdef CONFIG_LIBC_ARCH_STRCMP
+#undef strcmp
+no_builtin("strcmp")
 int strcmp(FAR const char *s1, FAR const char *s2)
 {
 #  ifdef CONFIG_MM_KASAN_INSTRUMENT
@@ -185,6 +194,8 @@ int strcmp(FAR const char *s1, FAR const char *s2)
 #endif
 
 #ifdef CONFIG_LIBC_ARCH_STRCPY
+#undef strcpy
+no_builtin("strcpy")
 FAR char *strcpy(FAR char *dest, FAR const char *src)
 {
 #  ifdef CONFIG_MM_KASAN_INSTRUMENT
@@ -200,6 +211,8 @@ FAR char *strcpy(FAR char *dest, FAR const char *src)
 #endif
 
 #ifdef CONFIG_LIBC_ARCH_STRLEN
+#undef strlen
+no_builtin("strlen")
 size_t strlen(FAR const char *s)
 {
   size_t ret = ARCH_LIBCFUN(strlen)(s);
@@ -213,6 +226,8 @@ size_t strlen(FAR const char *s)
 #endif
 
 #ifdef CONFIG_LIBC_ARCH_STRNCPY
+#undef strncpy
+no_builtin("strncpy")
 FAR char *strncpy(FAR char *dest, FAR const char *src, size_t n)
 {
 #  ifdef CONFIG_MM_KASAN_INSTRUMENT
@@ -228,6 +243,8 @@ FAR char *strncpy(FAR char *dest, FAR const char *src, size_t n)
 #endif
 
 #ifdef CONFIG_LIBC_ARCH_STRCHR
+#undef strchr
+no_builtin("strchr")
 FAR char *strchr(FAR const char *s, int c)
 {
 #  ifdef CONFIG_MM_KASAN_INSTRUMENT
@@ -253,6 +270,8 @@ FAR char *strchrnul(FAR const char *s, int c)
 #endif
 
 #ifdef CONFIG_LIBC_ARCH_STRNCMP
+#undef strncmp
+no_builtin("strncmp")
 int strncmp(FAR const char *s1, FAR const char *s2, size_t n)
 {
 #  ifdef CONFIG_MM_KASAN_INSTRUMENT
@@ -285,6 +304,8 @@ size_t strnlen(FAR const char *s, size_t maxlen)
 #endif
 
 #ifdef CONFIG_LIBC_ARCH_STRRCHR
+#undef strrchr
+no_builtin("strrchr")
 FAR char *strrchr(FAR const char *s, int c)
 {
 #  ifdef CONFIG_MM_KASAN_INSTRUMENT

libs/libc/string/lib_bsdmemchr.c

@@ -74,6 +74,7 @@
 
 #if !defined(CONFIG_LIBC_ARCH_MEMCHR) && defined(LIBC_BUILD_MEMCHR)
 #undef memchr
+no_builtin("memchr")
 FAR void *memchr(FAR const void *s, int c, size_t n)
 {
   FAR const unsigned char *p = (FAR const unsigned char *)s;

libs/libc/string/lib_bsdstpcpy.c

@@ -62,6 +62,7 @@
 
 #ifndef CONFIG_LIBC_ARCH_STPCPY
 #undef stpcpy
+no_builtin("stpcpy")
 nosanitize_address
 FAR char *stpcpy(FAR char *dest, FAR const char *src)
 {

libs/libc/string/lib_bsdstpncpy.c

@@ -78,6 +78,7 @@
 
 #ifndef CONFIG_LIBC_ARCH_STPNCPY
 #undef stpncpy
+no_builtin("stpncpy")
 FAR char *stpncpy(FAR char *dest, FAR const char *src, size_t n)
 {
   FAR char *ret = NULL;

libs/libc/string/lib_bsdstrcat.c

@@ -49,6 +49,7 @@
 
 #if !defined(CONFIG_LIBC_ARCH_STRCAT) && defined(LIBC_BUILD_STRCAT)
 #undef strcat
+no_builtin("strcat")
 nosanitize_address
 FAR char *strcat(FAR char *dest, FAR const char *src)
 {

libs/libc/string/lib_bsdstrchr.c

@@ -68,6 +68,7 @@
 
 #if !defined(CONFIG_LIBC_ARCH_STRCHR) && defined(LIBC_BUILD_STRCHR)
 #undef strchr
+no_builtin("strchr")
 nosanitize_address
 FAR char *strchr(FAR const char *s, int c)
 {

libs/libc/string/lib_bsdstrcmp.c

@@ -51,6 +51,7 @@
 
 #if !defined(CONFIG_LIBC_ARCH_STRCMP) && defined(LIBC_BUILD_STRCMP)
 #undef strcmp
+no_builtin("strcmp")
 nosanitize_address
 int strcmp(FAR const char *cs, FAR const char *ct)
 {

libs/libc/string/lib_bsdstrcpy.c

@@ -64,6 +64,7 @@
 #if !defined(CONFIG_LIBC_ARCH_STRCPY) && defined(LIBC_BUILD_STRCPY)
 #undef strcpy
 nosanitize_address
+no_builtin("strcpy")
 FAR char *strcpy(FAR char *dest, FAR const char *src)
 {
   FAR char *dst0 = dest;

libs/libc/string/lib_bsdstrlen.c

@@ -49,6 +49,7 @@
 
 #if !defined(CONFIG_LIBC_ARCH_STRLEN) && defined(LIBC_BUILD_STRLEN)
 #undef strlen
+no_builtin("strlen")
 nosanitize_address
 size_t strlen(FAR const char *s)
 {

libs/libc/string/lib_bsdstrncmp.c

@@ -53,6 +53,7 @@
 
 #if !defined(CONFIG_LIBC_ARCH_STRNCMP) && defined(LIBC_BUILD_STRNCMP)
 #undef strncmp
+no_builtin("strncmp")
 nosanitize_address
 int strncmp(FAR const char *cs, FAR const char *ct, size_t nb)
 {

libs/libc/string/lib_bsdstrncpy.c

@@ -77,6 +77,7 @@
 #if !defined(CONFIG_LIBC_ARCH_STRNCPY) && defined(LIBC_BUILD_STRNCPY)
 #undef strncpy
 nosanitize_address
+no_builtin("strncpy")
 FAR char *strncpy(FAR char *dest, FAR const char *src, size_t n)
 {
   FAR char *dst0 = dest;

libs/libc/string/lib_bsdstrrchr.c

@@ -36,6 +36,7 @@
 
 #if !defined(CONFIG_LIBC_ARCH_STRRCHR) && defined(LIBC_BUILD_STRRCHR)
 #undef strrchr
+no_builtin("strrchr")
 FAR char *strrchr(FAR const char *s, int c)
 {
   FAR const char *last = NULL;

libs/libc/string/lib_memchr.c

@@ -50,6 +50,7 @@
 
 #if !defined(CONFIG_LIBC_ARCH_MEMCHR) && defined(LIBC_BUILD_MEMCHR)
 #undef memchr
+no_builtin("memchr")
 FAR void *memchr(FAR const void *s, int c, size_t n)
 {
   FAR const unsigned char *p = (FAR const unsigned char *)s;

libs/libc/string/lib_strcat.c

@@ -36,6 +36,7 @@
 
 #if !defined(CONFIG_LIBC_ARCH_STRCAT) && defined(LIBC_BUILD_STRCAT)
 #undef strcat
+no_builtin("strcat")
 FAR char *strcat(FAR char *dest, FAR const char *src)
 {
   FAR char *ret = dest;

libs/libc/string/lib_strchr.c

@@ -50,6 +50,7 @@
 
 #if !defined(CONFIG_LIBC_ARCH_STRCHR) && defined(LIBC_BUILD_STRCHR)
 #undef strchr
+no_builtin("strchr")
 FAR char *strchr(FAR const char *s, int c)
 {
   for (; ; s++)

libs/libc/string/lib_strcpy.c

@@ -48,6 +48,7 @@
 
 #if !defined(CONFIG_LIBC_ARCH_STRCPY) && defined(LIBC_BUILD_STRCPY)
 #undef strcpy
+no_builtin("strcpy")
 FAR char *strcpy(FAR char *dest, FAR const char *src)
 {
   FAR char *tmp = dest;

libs/libc/string/lib_strcspn.c

@@ -42,6 +42,7 @@
  ****************************************************************************/
 
 #undef strcspn
+no_builtin("strcspn")
 size_t strcspn(const char *s, const char *reject)
 {
   size_t i;

libs/libc/string/lib_strlen.c

@@ -36,6 +36,7 @@
 
 #if !defined(CONFIG_LIBC_ARCH_STRLEN) && defined(LIBC_BUILD_STRLEN)
 #undef strlen
+no_builtin("strlen")
 size_t strlen(FAR const char *s)
 {
   FAR const char *sc;

libs/libc/string/lib_strncmp.c

@@ -36,6 +36,7 @@
 
 #if !defined(CONFIG_LIBC_ARCH_STRNCMP) && defined(LIBC_BUILD_STRNCMP)
 #undef strncmp
+no_builtin("strncmp")
 int strncmp(FAR const char *cs, FAR const char *ct, size_t nb)
 {
   register int result = 0;

libs/libc/string/lib_strrchr.c

@@ -40,6 +40,7 @@
 
 #if !defined(CONFIG_LIBC_ARCH_STRRCHR) && defined(LIBC_BUILD_STRRCHR)
 #undef strrchr
+no_builtin("strrchr")
 FAR char *strrchr(FAR const char *s, int c)
 {
   FAR const char *r = NULL;

libs/libc/string/lib_strstr.c

@@ -53,6 +53,7 @@
  */
 
 #undef strstr
+no_builtin("strstr")
 FAR char *strstr(FAR const char *haystack, FAR const char *needle)
 {
 #ifdef CONFIG_ALLOW_MIT_COMPONENTS