diff options
| author | Junio C Hamano <gitster@pobox.com> | 2025-07-24 16:03:56 -0700 |
|---|---|---|
| committer | Junio C Hamano <gitster@pobox.com> | 2025-07-24 16:03:56 -0700 |
| commit | 42eb2881587b3bc699f38b9b35861281b1ef316b (patch) | |
| tree | c257b87ec20c300e8a07d7b20dd811f140ad1234 | |
| parent | 0686fa42162f920b93d26ad1cd1ab1970f16706f (diff) | |
| parent | f4ac32c03af5ac53964a05c4de435da53a59615c (diff) | |
| download | git-42eb2881587b3bc699f38b9b35861281b1ef316b.tar.gz | |
Merge branch 'ss/compat-bswap-revamp'
Clean-up compat/bswap.h mess.
* ss/compat-bswap-revamp:
bswap.h: provide a built-in based version of bswap32/64 if possible
bswap.h: remove optimized x86 version of bswap32/64
bswap.h: always overwrite ntohl/ ntohll macros
bswap.h: define GIT_LITTLE_ENDIAN on msvc as little endian
bswap.h: add support for __BYTE_ORDER__
| -rw-r--r-- | compat/bswap.h | 110 |
1 files changed, 46 insertions, 64 deletions
diff --git a/compat/bswap.h b/compat/bswap.h index b34054f2bd..28635ebc69 100644 --- a/compat/bswap.h +++ b/compat/bswap.h @@ -32,78 +32,35 @@ static inline uint64_t default_bswap64(uint64_t val) ((val & (uint64_t)0xff00000000000000ULL) >> 56)); } +/* + * __has_builtin is available since Clang 10 and GCC 10. + * Below is a fallback for older compilers. + */ +#ifndef __has_builtin +# define __has_builtin(x) 0 +#endif + #undef bswap32 #undef bswap64 -#if defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__)) - -#define bswap32 git_bswap32 -static inline uint32_t git_bswap32(uint32_t x) -{ - uint32_t result; - if (__builtin_constant_p(x)) - result = default_swab32(x); - else - __asm__("bswap %0" : "=r" (result) : "0" (x)); - return result; -} - -#define bswap64 git_bswap64 -#if defined(__x86_64__) -static inline uint64_t git_bswap64(uint64_t x) -{ - uint64_t result; - if (__builtin_constant_p(x)) - result = default_bswap64(x); - else - __asm__("bswap %q0" : "=r" (result) : "0" (x)); - return result; -} -#else -static inline uint64_t git_bswap64(uint64_t x) -{ - union { uint64_t i64; uint32_t i32[2]; } tmp, result; - if (__builtin_constant_p(x)) - result.i64 = default_bswap64(x); - else { - tmp.i64 = x; - result.i32[0] = git_bswap32(tmp.i32[1]); - result.i32[1] = git_bswap32(tmp.i32[0]); - } - return result.i64; -} -#endif - -#elif defined(_MSC_VER) && (defined(_M_IX86) || defined(_M_X64) || defined(_M_ARM64)) +#if defined(_MSC_VER) && (defined(_M_IX86) || defined(_M_X64) || defined(_M_ARM64)) #include <stdlib.h> #define bswap32(x) _byteswap_ulong(x) #define bswap64(x) _byteswap_uint64(x) -#endif +#define GIT_LITTLE_ENDIAN 1234 +#define GIT_BIG_ENDIAN 4321 +#define GIT_BYTE_ORDER GIT_LITTLE_ENDIAN -#if defined(bswap32) +#elif __has_builtin(__builtin_bswap32) && __has_builtin(__builtin_bswap64) -#undef ntohl -#undef htonl -#define ntohl(x) bswap32(x) -#define htonl(x) bswap32(x) +#define bswap32(x) __builtin_bswap32((x)) +#define bswap64(x) __builtin_bswap64((x)) #endif -#if defined(bswap64) - -#undef ntohll -#undef htonll -#define ntohll(x) bswap64(x) -#define htonll(x) bswap64(x) - -#else - -#undef ntohll -#undef htonll - #if defined(__BYTE_ORDER) && defined(__LITTLE_ENDIAN) && defined(__BIG_ENDIAN) # define GIT_BYTE_ORDER __BYTE_ORDER @@ -116,7 +73,13 @@ static inline uint64_t git_bswap64(uint64_t x) # define GIT_LITTLE_ENDIAN LITTLE_ENDIAN # define GIT_BIG_ENDIAN BIG_ENDIAN -#else +#elif defined(__BYTE_ORDER__) && defined(__ORDER_LITTLE_ENDIAN__) && defined(__ORDER_BIG_ENDIAN__) + +# define GIT_BYTE_ORDER __BYTE_ORDER__ +# define GIT_LITTLE_ENDIAN __ORDER_LITTLE_ENDIAN__ +# define GIT_BIG_ENDIAN __ORDER_BIG_ENDIAN__ + +#elif !defined(GIT_BYTE_ORDER) # define GIT_BIG_ENDIAN 4321 # define GIT_LITTLE_ENDIAN 1234 @@ -135,14 +98,33 @@ static inline uint64_t git_bswap64(uint64_t x) #endif +#undef ntohl +#undef htonl +#undef ntohll +#undef htonll + #if GIT_BYTE_ORDER == GIT_BIG_ENDIAN -# define ntohll(n) (n) -# define htonll(n) (n) +# define ntohl(x) (x) +# define htonl(x) (x) +# define ntohll(x) (x) +# define htonll(x) (x) #else -# define ntohll(n) default_bswap64(n) -# define htonll(n) default_bswap64(n) -#endif +# if defined(bswap32) +# define ntohl(x) bswap32(x) +# define htonl(x) bswap32(x) +# else +# define ntohl(x) default_swab32(x) +# define htonl(x) default_swab32(x) +# endif + +# if defined(bswap64) +# define ntohll(x) bswap64(x) +# define htonll(x) bswap64(x) +# else +# define ntohll(x) default_bswap64(x) +# define htonll(x) default_bswap64(x) +# endif #endif static inline uint16_t get_be16(const void *ptr) |