diff options
Diffstat (limited to 'extract.h')
| -rw-r--r-- | extract.h | 49 |
1 files changed, 41 insertions, 8 deletions
@@ -20,8 +20,41 @@ */ /* - * Macros to extract possibly-unaligned big-endian integral values. + * Inline functions or macros to extract possibly-unaligned big-endian + * integral values. */ +#include "funcattrs.h" + +/* + * If we have versions of GCC or Clang that support an __attribute__ + * to say "if we're building with unsigned behavior sanitization, + * don't complain about undefined behavior in this function", we + * label these functions with that attribute - we *know* it's undefined + * in the C standard, but we *also* know it does what we want with + * the ISA we're targeting and the compiler we're using. + * + * For GCC 4.9.0 and later, we use __attribute__((no_sanitize_undefined)); + * pre-5.0 GCC doesn't have __has_attribute, and I'm not sure whether + * GCC or Clang first had __attribute__((no_sanitize(XXX)). + * + * For Clang, we check for __attribute__((no_sanitize(XXX)) with + * __has_attribute, as there are versions of Clang that support + * __attribute__((no_sanitize("undefined")) but don't support + * __attribute__((no_sanitize_undefined)). + * + * We define this here, rather than in funcattrs.h, because we + * only want it used here, we don't want it to be broadly used. + * (Any printer will get this defined, but this should at least + * make it harder for people to find.) + */ +#if defined(__GNUC__) && ((__GNUC__ * 100 + __GNUC_MINOR__) >= 409) +#define UNALIGNED_OK __attribute__((no_sanitize_undefined)) +#elif __has_attribute(no_sanitize) +#define UNALIGNED_OK __attribute__((no_sanitize("undefined"))) +#else +#define UNALIGNED_OK +#endif + #ifdef LBL_ALIGN /* * The processor doesn't natively handle unaligned loads. @@ -31,7 +64,7 @@ defined(__mips) || defined(__mips__)) /* - * This is a GCC-compatible compiler and we have __attribute__, which +* This is a GCC-compatible compiler and we have __attribute__, which * we assume that mean we have __attribute__((packed)), and this is * MIPS or Alpha, which has instructions that can help when doing * unaligned loads. @@ -88,19 +121,19 @@ typedef struct { uint32_t val; } __attribute__((packed)) unaligned_uint32_t; -static inline uint16_t +UNALIGNED_OK static inline uint16_t EXTRACT_16BITS(const void *p) { return ((uint16_t)ntohs(((const unaligned_uint16_t *)(p))->val)); } -static inline uint32_t +UNALIGNED_OK static inline uint32_t EXTRACT_32BITS(const void *p) { return ((uint32_t)ntohl(((const unaligned_uint32_t *)(p))->val)); } -static inline uint64_t +UNALIGNED_OK static inline uint64_t EXTRACT_64BITS(const void *p) { return ((uint64_t)(((uint64_t)ntohl(((const unaligned_uint32_t *)(p) + 0)->val)) << 32 | @@ -138,19 +171,19 @@ EXTRACT_64BITS(const void *p) * The processor natively handles unaligned loads, so we can just * cast the pointer and fetch through it. */ -static inline uint16_t +static inline uint16_t UNALIGNED_OK EXTRACT_16BITS(const void *p) { return ((uint16_t)ntohs(*(const uint16_t *)(p))); } -static inline uint32_t +static inline uint32_t UNALIGNED_OK EXTRACT_32BITS(const void *p) { return ((uint32_t)ntohl(*(const uint32_t *)(p))); } -static inline uint64_t +static inline uint64_t UNALIGNED_OK EXTRACT_64BITS(const void *p) { return ((uint64_t)(((uint64_t)ntohl(*((const uint32_t *)(p) + 0))) << 32 | |