From 432b18ca8d0654318a8d882b28b20af2cb2d2e5d Mon Sep 17 00:00:00 2001 From: Cory Fields Date: Tue, 27 Feb 2024 18:29:24 +0000 Subject: [PATCH] serialization: detect byteswap builtins without autoconf tests Rather than a complicated set of tests to decide which bswap functions to use, always prefer the compiler built-ins when available. These builtins and fallbacks can all be removed once we're using c++23, which adds std::byteswap. --- configure.ac | 7 +---- src/compat/byteswap.h | 68 ++++++++++++++++++++++++++-------------- src/compat/endian.h | 24 +++++++------- src/test/bswap_tests.cpp | 6 ++-- 4 files changed, 60 insertions(+), 45 deletions(-) diff --git a/configure.ac b/configure.ac index 50e6870dd93..882bd01075b 100644 --- a/configure.ac +++ b/configure.ac @@ -975,7 +975,7 @@ if test "$TARGET_OS" = "darwin"; then AX_CHECK_LINK_FLAG([-Wl,-fixup_chains], [HARDENED_LDFLAGS="$HARDENED_LDFLAGS -Wl,-fixup_chains"], [], [$LDFLAG_WERROR]) fi -AC_CHECK_HEADERS([endian.h sys/endian.h byteswap.h sys/select.h sys/prctl.h sys/sysctl.h vm/vm_param.h sys/vmmeter.h sys/resources.h]) +AC_CHECK_HEADERS([endian.h sys/endian.h sys/select.h sys/prctl.h sys/sysctl.h vm/vm_param.h sys/vmmeter.h sys/resources.h]) AC_CHECK_DECLS([getifaddrs, freeifaddrs],[CHECK_SOCKET],, [#include @@ -997,11 +997,6 @@ AC_CHECK_DECLS([le16toh, le32toh, le64toh, htole16, htole32, htole64, be16toh, b #include #endif]) -AC_CHECK_DECLS([bswap_16, bswap_32, bswap_64],,, - [#if HAVE_BYTESWAP_H - #include - #endif]) - AC_MSG_CHECKING([for __builtin_clzl]) AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[ ]], [[ (void) __builtin_clzl(0); diff --git a/src/compat/byteswap.h b/src/compat/byteswap.h index 9ee71ef267d..0d0b079230e 100644 --- a/src/compat/byteswap.h +++ b/src/compat/byteswap.h @@ -5,44 +5,66 @@ #ifndef BITCOIN_COMPAT_BYTESWAP_H #define BITCOIN_COMPAT_BYTESWAP_H -#if defined(HAVE_CONFIG_H) -#include -#endif - #include - -#if defined(HAVE_BYTESWAP_H) -#include +#ifdef _MSC_VER +#include #endif -#if defined(MAC_OSX) -#include -#define bswap_16(x) OSSwapInt16(x) -#define bswap_32(x) OSSwapInt32(x) -#define bswap_64(x) OSSwapInt64(x) +// All internal_bswap_* functions can be replaced with std::byteswap once we +// require c++23. Both libstdc++ and libc++ implement std::byteswap via these +// builtins. +#ifndef DISABLE_BUILTIN_BSWAPS +# if defined __has_builtin +# if __has_builtin(__builtin_bswap16) +# define bitcoin_builtin_bswap16(x) __builtin_bswap16(x) +# endif +# if __has_builtin(__builtin_bswap32) +# define bitcoin_builtin_bswap32(x) __builtin_bswap32(x) +# endif +# if __has_builtin(__builtin_bswap64) +# define bitcoin_builtin_bswap64(x) __builtin_bswap64(x) +# endif +# elif defined(_MSC_VER) +# define bitcoin_builtin_bswap16(x) _byteswap_ushort(x) +# define bitcoin_builtin_bswap32(x) _byteswap_ulong(x) +# define bitcoin_builtin_bswap64(x) _byteswap_uint64(x) +# endif +#endif + +// MSVC's _byteswap_* functions are not constexpr + +#ifndef _MSC_VER +#define BSWAP_CONSTEXPR constexpr #else -// Non-MacOS / non-Darwin +#define BSWAP_CONSTEXPR +#endif -#if HAVE_DECL_BSWAP_16 == 0 -inline uint16_t bswap_16(uint16_t x) +inline BSWAP_CONSTEXPR uint16_t internal_bswap_16(uint16_t x) { +#ifdef bitcoin_builtin_bswap16 + return bitcoin_builtin_bswap16(x); +#else return (x >> 8) | (x << 8); +#endif } -#endif // HAVE_DECL_BSWAP16 == 0 -#if HAVE_DECL_BSWAP_32 == 0 -inline uint32_t bswap_32(uint32_t x) +inline BSWAP_CONSTEXPR uint32_t internal_bswap_32(uint32_t x) { +#ifdef bitcoin_builtin_bswap32 + return bitcoin_builtin_bswap32(x); +#else return (((x & 0xff000000U) >> 24) | ((x & 0x00ff0000U) >> 8) | ((x & 0x0000ff00U) << 8) | ((x & 0x000000ffU) << 24)); +#endif } -#endif // HAVE_DECL_BSWAP32 == 0 -#if HAVE_DECL_BSWAP_64 == 0 -inline uint64_t bswap_64(uint64_t x) +inline BSWAP_CONSTEXPR uint64_t internal_bswap_64(uint64_t x) { +#ifdef bitcoin_builtin_bswap64 + return bitcoin_builtin_bswap64(x); +#else return (((x & 0xff00000000000000ull) >> 56) | ((x & 0x00ff000000000000ull) >> 40) | ((x & 0x0000ff0000000000ull) >> 24) @@ -51,9 +73,7 @@ inline uint64_t bswap_64(uint64_t x) | ((x & 0x0000000000ff0000ull) << 24) | ((x & 0x000000000000ff00ull) << 40) | ((x & 0x00000000000000ffull) << 56)); +#endif } -#endif // HAVE_DECL_BSWAP64 == 0 - -#endif // defined(MAC_OSX) #endif // BITCOIN_COMPAT_BYTESWAP_H diff --git a/src/compat/endian.h b/src/compat/endian.h index 882de2dbf0e..70161409f85 100644 --- a/src/compat/endian.h +++ b/src/compat/endian.h @@ -76,7 +76,7 @@ inline uint16_t htobe16(uint16_t host_16bits) #if HAVE_DECL_HTOLE16 == 0 inline uint16_t htole16(uint16_t host_16bits) { - return bswap_16(host_16bits); + return internal_bswap_16(host_16bits); } #endif // HAVE_DECL_HTOLE16 @@ -90,7 +90,7 @@ inline uint16_t be16toh(uint16_t big_endian_16bits) #if HAVE_DECL_LE16TOH == 0 inline uint16_t le16toh(uint16_t little_endian_16bits) { - return bswap_16(little_endian_16bits); + return internal_bswap_16(little_endian_16bits); } #endif // HAVE_DECL_LE16TOH @@ -104,7 +104,7 @@ inline uint32_t htobe32(uint32_t host_32bits) #if HAVE_DECL_HTOLE32 == 0 inline uint32_t htole32(uint32_t host_32bits) { - return bswap_32(host_32bits); + return internal_bswap_32(host_32bits); } #endif // HAVE_DECL_HTOLE32 @@ -118,7 +118,7 @@ inline uint32_t be32toh(uint32_t big_endian_32bits) #if HAVE_DECL_LE32TOH == 0 inline uint32_t le32toh(uint32_t little_endian_32bits) { - return bswap_32(little_endian_32bits); + return internal_bswap_32(little_endian_32bits); } #endif // HAVE_DECL_LE32TOH @@ -132,7 +132,7 @@ inline uint64_t htobe64(uint64_t host_64bits) #if HAVE_DECL_HTOLE64 == 0 inline uint64_t htole64(uint64_t host_64bits) { - return bswap_64(host_64bits); + return internal_bswap_64(host_64bits); } #endif // HAVE_DECL_HTOLE64 @@ -146,7 +146,7 @@ inline uint64_t be64toh(uint64_t big_endian_64bits) #if HAVE_DECL_LE64TOH == 0 inline uint64_t le64toh(uint64_t little_endian_64bits) { - return bswap_64(little_endian_64bits); + return internal_bswap_64(little_endian_64bits); } #endif // HAVE_DECL_LE64TOH @@ -155,7 +155,7 @@ inline uint64_t le64toh(uint64_t little_endian_64bits) #if HAVE_DECL_HTOBE16 == 0 inline uint16_t htobe16(uint16_t host_16bits) { - return bswap_16(host_16bits); + return internal_bswap_16(host_16bits); } #endif // HAVE_DECL_HTOBE16 @@ -169,7 +169,7 @@ inline uint16_t htole16(uint16_t host_16bits) #if HAVE_DECL_BE16TOH == 0 inline uint16_t be16toh(uint16_t big_endian_16bits) { - return bswap_16(big_endian_16bits); + return internal_bswap_16(big_endian_16bits); } #endif // HAVE_DECL_BE16TOH @@ -183,7 +183,7 @@ inline uint16_t le16toh(uint16_t little_endian_16bits) #if HAVE_DECL_HTOBE32 == 0 inline uint32_t htobe32(uint32_t host_32bits) { - return bswap_32(host_32bits); + return internal_bswap_32(host_32bits); } #endif // HAVE_DECL_HTOBE32 @@ -197,7 +197,7 @@ inline uint32_t htole32(uint32_t host_32bits) #if HAVE_DECL_BE32TOH == 0 inline uint32_t be32toh(uint32_t big_endian_32bits) { - return bswap_32(big_endian_32bits); + return internal_bswap_32(big_endian_32bits); } #endif // HAVE_DECL_BE32TOH @@ -211,7 +211,7 @@ inline uint32_t le32toh(uint32_t little_endian_32bits) #if HAVE_DECL_HTOBE64 == 0 inline uint64_t htobe64(uint64_t host_64bits) { - return bswap_64(host_64bits); + return internal_bswap_64(host_64bits); } #endif // HAVE_DECL_HTOBE64 @@ -225,7 +225,7 @@ inline uint64_t htole64(uint64_t host_64bits) #if HAVE_DECL_BE64TOH == 0 inline uint64_t be64toh(uint64_t big_endian_64bits) { - return bswap_64(big_endian_64bits); + return internal_bswap_64(big_endian_64bits); } #endif // HAVE_DECL_BE64TOH diff --git a/src/test/bswap_tests.cpp b/src/test/bswap_tests.cpp index 2be7122fc16..fe48e39c418 100644 --- a/src/test/bswap_tests.cpp +++ b/src/test/bswap_tests.cpp @@ -16,9 +16,9 @@ BOOST_AUTO_TEST_CASE(bswap_tests) uint16_t e1 = 0x3412; uint32_t e2 = 0xbc9a7856; uint64_t e3 = 0xbc9a78563412f0de; - BOOST_CHECK(bswap_16(u1) == e1); - BOOST_CHECK(bswap_32(u2) == e2); - BOOST_CHECK(bswap_64(u3) == e3); + BOOST_CHECK(internal_bswap_16(u1) == e1); + BOOST_CHECK(internal_bswap_32(u2) == e2); + BOOST_CHECK(internal_bswap_64(u3) == e3); } BOOST_AUTO_TEST_SUITE_END()