This is an automated email from the ASF dual-hosted git repository.
xiaoxiang pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/nuttx.git
The following commit(s) were added to refs/heads/master by this push:
new 7c96537a58b string:use builtin function to optimize libc function
7c96537a58b is described below
commit 7c96537a58b125cdc16f8ff2ea668def13bc9413
Author: anjiahao <[email protected]>
AuthorDate: Fri Jan 10 11:46:01 2025 +0800
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 <[email protected]>
---
include/nuttx/compiler.h | 7 ++
include/string.h | 226 ++++++++++++++++++++++++++++++++++++++
libs/libc/machine/arch_libc.c | 23 +++-
libs/libc/string/lib_bsdmemchr.c | 1 +
libs/libc/string/lib_bsdstpcpy.c | 1 +
libs/libc/string/lib_bsdstpncpy.c | 1 +
libs/libc/string/lib_bsdstrcat.c | 1 +
libs/libc/string/lib_bsdstrchr.c | 1 +
libs/libc/string/lib_bsdstrcmp.c | 1 +
libs/libc/string/lib_bsdstrcpy.c | 1 +
libs/libc/string/lib_bsdstrlen.c | 1 +
libs/libc/string/lib_bsdstrncmp.c | 1 +
libs/libc/string/lib_bsdstrncpy.c | 1 +
libs/libc/string/lib_bsdstrrchr.c | 1 +
libs/libc/string/lib_memchr.c | 1 +
libs/libc/string/lib_strcat.c | 1 +
libs/libc/string/lib_strchr.c | 1 +
libs/libc/string/lib_strcpy.c | 1 +
libs/libc/string/lib_strcspn.c | 1 +
libs/libc/string/lib_strlen.c | 1 +
libs/libc/string/lib_strncmp.c | 1 +
libs/libc/string/lib_strrchr.c | 1 +
libs/libc/string/lib_strstr.c | 1 +
23 files changed, 275 insertions(+), 1 deletion(-)
diff --git a/include/nuttx/compiler.h b/include/nuttx/compiler.h
index 63588bb6e24..99c1efd3b1b 100644
--- a/include/nuttx/compiler.h
+++ b/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 */
diff --git a/include/string.h b/include/string.h
index dd8a92c4306..1cfc1e04e56 100644
--- a/include/string.h
+++ b/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)
}
diff --git a/libs/libc/machine/arch_libc.c b/libs/libc/machine/arch_libc.c
index 0cce4c4d227..aaad3f83fdb 100644
--- a/libs/libc/machine/arch_libc.c
+++ b/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
diff --git a/libs/libc/string/lib_bsdmemchr.c b/libs/libc/string/lib_bsdmemchr.c
index de33da42d15..fd4f7ad88fa 100644
--- a/libs/libc/string/lib_bsdmemchr.c
+++ b/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;
diff --git a/libs/libc/string/lib_bsdstpcpy.c b/libs/libc/string/lib_bsdstpcpy.c
index 5c6f36767f0..0949c67e84d 100644
--- a/libs/libc/string/lib_bsdstpcpy.c
+++ b/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)
{
diff --git a/libs/libc/string/lib_bsdstpncpy.c
b/libs/libc/string/lib_bsdstpncpy.c
index 79fb41b21b0..bc1708170b1 100644
--- a/libs/libc/string/lib_bsdstpncpy.c
+++ b/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;
diff --git a/libs/libc/string/lib_bsdstrcat.c b/libs/libc/string/lib_bsdstrcat.c
index f04d9e4ca0a..86e65001016 100644
--- a/libs/libc/string/lib_bsdstrcat.c
+++ b/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)
{
diff --git a/libs/libc/string/lib_bsdstrchr.c b/libs/libc/string/lib_bsdstrchr.c
index a910e881e2e..4446c173285 100644
--- a/libs/libc/string/lib_bsdstrchr.c
+++ b/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)
{
diff --git a/libs/libc/string/lib_bsdstrcmp.c b/libs/libc/string/lib_bsdstrcmp.c
index 9366d0d0a9f..b8ba758a3cb 100644
--- a/libs/libc/string/lib_bsdstrcmp.c
+++ b/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)
{
diff --git a/libs/libc/string/lib_bsdstrcpy.c b/libs/libc/string/lib_bsdstrcpy.c
index 95e221de6c5..bf352ade5af 100644
--- a/libs/libc/string/lib_bsdstrcpy.c
+++ b/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;
diff --git a/libs/libc/string/lib_bsdstrlen.c b/libs/libc/string/lib_bsdstrlen.c
index efd117ae0ed..992f40f01b9 100644
--- a/libs/libc/string/lib_bsdstrlen.c
+++ b/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)
{
diff --git a/libs/libc/string/lib_bsdstrncmp.c
b/libs/libc/string/lib_bsdstrncmp.c
index 4f7d12823e2..a1f7441eebb 100644
--- a/libs/libc/string/lib_bsdstrncmp.c
+++ b/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)
{
diff --git a/libs/libc/string/lib_bsdstrncpy.c
b/libs/libc/string/lib_bsdstrncpy.c
index 0012804fbaa..a35c7dd40f5 100644
--- a/libs/libc/string/lib_bsdstrncpy.c
+++ b/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;
diff --git a/libs/libc/string/lib_bsdstrrchr.c
b/libs/libc/string/lib_bsdstrrchr.c
index 22dbcb6b698..50ab3d58779 100644
--- a/libs/libc/string/lib_bsdstrrchr.c
+++ b/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;
diff --git a/libs/libc/string/lib_memchr.c b/libs/libc/string/lib_memchr.c
index dcacfde4b69..08555b79a5d 100644
--- a/libs/libc/string/lib_memchr.c
+++ b/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;
diff --git a/libs/libc/string/lib_strcat.c b/libs/libc/string/lib_strcat.c
index a7692eae14a..882c9ccae42 100644
--- a/libs/libc/string/lib_strcat.c
+++ b/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;
diff --git a/libs/libc/string/lib_strchr.c b/libs/libc/string/lib_strchr.c
index c60ba071def..9002dbae8f5 100644
--- a/libs/libc/string/lib_strchr.c
+++ b/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++)
diff --git a/libs/libc/string/lib_strcpy.c b/libs/libc/string/lib_strcpy.c
index d4244fe33b7..011ed3efbb7 100644
--- a/libs/libc/string/lib_strcpy.c
+++ b/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;
diff --git a/libs/libc/string/lib_strcspn.c b/libs/libc/string/lib_strcspn.c
index 163d3ab9b08..82bd46ef06d 100644
--- a/libs/libc/string/lib_strcspn.c
+++ b/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;
diff --git a/libs/libc/string/lib_strlen.c b/libs/libc/string/lib_strlen.c
index 919940b15a5..b77d2300ddb 100644
--- a/libs/libc/string/lib_strlen.c
+++ b/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;
diff --git a/libs/libc/string/lib_strncmp.c b/libs/libc/string/lib_strncmp.c
index 02ffef9b467..00ab1e753fe 100644
--- a/libs/libc/string/lib_strncmp.c
+++ b/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;
diff --git a/libs/libc/string/lib_strrchr.c b/libs/libc/string/lib_strrchr.c
index db683445652..873e9b66ac8 100644
--- a/libs/libc/string/lib_strrchr.c
+++ b/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;
diff --git a/libs/libc/string/lib_strstr.c b/libs/libc/string/lib_strstr.c
index bcd5d265a4d..67cbbd2ad6d 100644
--- a/libs/libc/string/lib_strstr.c
+++ b/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
