diff options
| -rw-r--r-- | src/fns.c | 43 | ||||
| -rw-r--r-- | src/lisp.h | 20 |
2 files changed, 25 insertions, 38 deletions
diff --git a/src/fns.c b/src/fns.c index 0af9b725c7a..94505eda444 100644 --- a/src/fns.c +++ b/src/fns.c @@ -439,17 +439,29 @@ If string STR1 is greater, the value is a positive number N; } /* Check whether the platform allows access to unaligned addresses for - size_t integers without trapping or undue penalty (a few cycles is OK). + size_t integers without trapping or undue penalty (a few cycles is OK), + and that a word-sized memcpy can be used to generate such an access. This whitelist is incomplete but since it is only used to improve performance, omitting cases is safe. */ -#if defined __x86_64__|| defined __amd64__ \ - || defined __i386__ || defined __i386 \ - || defined __arm64__ || defined __aarch64__ \ - || defined __powerpc__ || defined __powerpc \ - || defined __ppc__ || defined __ppc \ - || defined __s390__ || defined __s390x__ +#if (defined __x86_64__|| defined __amd64__ \ + || defined __i386__ || defined __i386 \ + || defined __arm64__ || defined __aarch64__ \ + || defined __powerpc__ || defined __powerpc \ + || defined __ppc__ || defined __ppc \ + || defined __s390__ || defined __s390x__) \ + && defined __OPTIMIZE__ #define HAVE_FAST_UNALIGNED_ACCESS 1 + +/* Load a word from a possibly unaligned address. */ +static inline size_t +load_unaligned_size_t (const void *p) +{ + size_t x; + memcpy (&x, p, sizeof x); + return x; +} + #else #define HAVE_FAST_UNALIGNED_ACCESS 0 #endif @@ -497,17 +509,12 @@ Symbols are also allowed; their print names are used instead. */) if (HAVE_FAST_UNALIGNED_ACCESS) { /* First compare entire machine words. */ - typedef size_t word_t; - int ws = sizeof (word_t); - const word_t *w1 = (const word_t *) SDATA (string1); - const word_t *w2 = (const word_t *) SDATA (string2); - while (b < nb - ws + 1) - { - if (UNALIGNED_LOAD_SIZE (w1, b / ws) - != UNALIGNED_LOAD_SIZE (w2, b / ws)) - break; - b += ws; - } + int ws = sizeof (size_t); + const char *w1 = SSDATA (string1); + const char *w2 = SSDATA (string2); + while (b < nb - ws + 1 && load_unaligned_size_t (w1 + b) + == load_unaligned_size_t (w2 + b)) + b += ws; } /* Scan forward to the differing byte. */ diff --git a/src/lisp.h b/src/lisp.h index cacd318c26f..165fa47b0b3 100644 --- a/src/lisp.h +++ b/src/lisp.h @@ -5305,26 +5305,6 @@ __lsan_ignore_object (void const *p) } #endif -/* If built with USE_SANITIZER_UNALIGNED_LOAD defined, use compiler - provided ASan functions to perform unaligned loads, allowing ASan - to catch bugs which it might otherwise miss. */ -#if defined HAVE_SANITIZER_COMMON_INTERFACE_DEFS_H \ - && defined ADDRESS_SANITIZER \ - && defined USE_SANITIZER_UNALIGNED_LOAD -# include <sanitizer/common_interface_defs.h> -# if (SIZE_MAX == UINT64_MAX) -# define UNALIGNED_LOAD_SIZE(a, i) \ - (size_t) __sanitizer_unaligned_load64 ((void *) ((a) + (i))) -# elif (SIZE_MAX == UINT32_MAX) -# define UNALIGNED_LOAD_SIZE(a, i) \ - (size_t) __sanitizer_unaligned_load32 ((void *) ((a) + (i))) -# else -# define UNALIGNED_LOAD_SIZE(a, i) *((a) + (i)) -# endif -#else -# define UNALIGNED_LOAD_SIZE(a, i) *((a) + (i)) -#endif - extern void xputenv (const char *); extern char *egetenv_internal (const char *, ptrdiff_t); |