Date: Sat, 31 Jan 2009 18:27:02 +0000 (UTC) From: David Schultz <das@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r187961 - in head: include sys/sys Message-ID: <200901311827.n0VIR2WF031218@svn.freebsd.org>
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Author: das Date: Sat Jan 31 18:27:02 2009 New Revision: 187961 URL: http://svn.freebsd.org/changeset/base/187961 Log: Add a function attribute called `__malloc_like', which informs gcc that the annotated function returns a pointer that doesn't alias any extant pointer. This results in a 50%+ speedup in microbenchmarks such as the following: char *cp = malloc(1), *buf = malloc(BUF); for (i = 0; i < BUF; i++) buf[i] = *cp; In real programs, your mileage will vary. Note that gcc already performs this optimization automatically for any function called `malloc', `calloc', `strdup', or `strndup' unless -fno-builtins is used. Modified: head/include/stdlib.h head/include/string.h head/include/wchar.h head/sys/sys/cdefs.h head/sys/sys/malloc.h Modified: head/include/stdlib.h ============================================================================== --- head/include/stdlib.h Sat Jan 31 18:06:34 2009 (r187960) +++ head/include/stdlib.h Sat Jan 31 18:27:02 2009 (r187961) @@ -88,14 +88,14 @@ int atoi(const char *); long atol(const char *); void *bsearch(const void *, const void *, size_t, size_t, int (*)(const void *, const void *)); -void *calloc(size_t, size_t); +void *calloc(size_t, size_t) __malloc_like; div_t div(int, int) __pure2; void exit(int) __dead2; void free(void *); char *getenv(const char *); long labs(long) __pure2; ldiv_t ldiv(long, long) __pure2; -void *malloc(size_t); +void *malloc(size_t) __malloc_like; int mblen(const char *, size_t); size_t mbstowcs(wchar_t * __restrict , const char * __restrict, size_t); int mbtowc(wchar_t * __restrict, const char * __restrict, size_t); Modified: head/include/string.h ============================================================================== --- head/include/string.h Sat Jan 31 18:06:34 2009 (r187960) +++ head/include/string.h Sat Jan 31 18:27:02 2009 (r187961) @@ -78,7 +78,7 @@ int strcoll(const char *, const char *) char *strcpy(char * __restrict, const char * __restrict); size_t strcspn(const char *, const char *) __pure; #if __POSIX_VISIBLE >= 200112 || __XSI_VISIBLE -char *strdup(const char *); +char *strdup(const char *) __malloc_like; #endif char *strerror(int); #if __POSIX_VISIBLE >= 200112 @@ -96,7 +96,7 @@ char *strncat(char * __restrict, const c int strncmp(const char *, const char *, size_t) __pure; char *strncpy(char * __restrict, const char * __restrict, size_t); #if __BSD_VISIBLE -char *strndup(const char *, size_t); +char *strndup(const char *, size_t) __malloc_like; char *strnstr(const char *, const char *, size_t) __pure; #endif char *strpbrk(const char *, const char *) __pure; Modified: head/include/wchar.h ============================================================================== --- head/include/wchar.h Sat Jan 31 18:06:34 2009 (r187960) +++ head/include/wchar.h Sat Jan 31 18:27:02 2009 (r187961) @@ -214,7 +214,7 @@ int wcwidth(wchar_t); wchar_t *fgetwln(struct __sFILE * __restrict, size_t * __restrict); size_t mbsnrtowcs(wchar_t * __restrict, const char ** __restrict, size_t, size_t, mbstate_t * __restrict); -wchar_t *wcsdup(const wchar_t *); +wchar_t *wcsdup(const wchar_t *) __malloc_like; size_t wcsnrtombs(char * __restrict, const wchar_t ** __restrict, size_t, size_t, mbstate_t * __restrict); size_t wcslcat(wchar_t *, const wchar_t *, size_t); Modified: head/sys/sys/cdefs.h ============================================================================== --- head/sys/sys/cdefs.h Sat Jan 31 18:06:34 2009 (r187960) +++ head/sys/sys/cdefs.h Sat Jan 31 18:27:02 2009 (r187961) @@ -221,8 +221,10 @@ #endif #if __GNUC_PREREQ__(2, 96) +#define __malloc_like __attribute__((__malloc__)) #define __pure __attribute__((__pure__)) #else +#define __malloc_like #define __pure #endif Modified: head/sys/sys/malloc.h ============================================================================== --- head/sys/sys/malloc.h Sat Jan 31 18:06:34 2009 (r187960) +++ head/sys/sys/malloc.h Sat Jan 31 18:27:02 2009 (r187961) @@ -190,9 +190,9 @@ typedef void malloc_type_list_func_t(str void contigfree(void *addr, unsigned long size, struct malloc_type *type); void *contigmalloc(unsigned long size, struct malloc_type *type, int flags, vm_paddr_t low, vm_paddr_t high, unsigned long alignment, - unsigned long boundary); + unsigned long boundary) __malloc_like; void free(void *addr, struct malloc_type *type); -void *malloc(unsigned long size, struct malloc_type *type, int flags); +void *malloc(unsigned long size, struct malloc_type *type, int flags) __malloc_like; void malloc_init(void *); int malloc_last_fail(void); void malloc_type_allocated(struct malloc_type *type, unsigned long size);
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