X-Git-Url: https://wimlib.net/git/?p=wimlib;a=blobdiff_plain;f=include%2Fwimlib%2Fcompiler.h;h=2b1923c263f6c054c642d0b7c9b518b4e769f736;hp=19a9ebe70c6763cd9efb91242487a80eb45dd78d;hb=4a20aae0dd8469a352517a0b107416ffa99ccc55;hpb=9b3bd8bf81681c6ac3216f62bbf7c7cf63e9bb17 diff --git a/include/wimlib/compiler.h b/include/wimlib/compiler.h index 19a9ebe7..2b1923c2 100644 --- a/include/wimlib/compiler.h +++ b/include/wimlib/compiler.h @@ -1,33 +1,203 @@ +/* + * compiler.h + * + * Compiler-specific definitions. Currently, only GCC and clang are supported. + * + * The following copying information applies to this specific source code file: + * + * Written in 2013-2016 by Eric Biggers + * + * To the extent possible under law, the author(s) have dedicated all copyright + * and related and neighboring rights to this software to the public domain + * worldwide via the Creative Commons Zero 1.0 Universal Public Domain + * Dedication (the "CC0"). + * + * This software is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS + * FOR A PARTICULAR PURPOSE. See the CC0 for more details. + * + * You should have received a copy of the CC0 along with this software; if not + * see . + */ + #ifndef _WIMLIB_COMPILER_H #define _WIMLIB_COMPILER_H -#ifdef __GNUC__ -# if defined(__CYGWIN__) || defined(__WIN32__) -# define WIMLIBAPI __declspec(dllexport) -# else -# define WIMLIBAPI __attribute__((visibility("default"))) -# endif -# define _always_inline_attribute inline __attribute__((always_inline)) -# define _packed_attribute __attribute__((packed)) -# define _format_attribute(type, format_str, args_start) \ - /*__attribute__((format(type, format_str, args_start))) */ -# if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 4) -# define _cold_attribute __attribute__((cold)) -# else -# define _cold_attribute -# endif -# define _malloc_attribute __attribute__((malloc)) -# define _warn_unused_result_attribute __attribute__((warn_unused_result)) -# define _aligned_attribute(size) __attribute__((aligned(size))) +/* Is the compiler GCC of the specified version or later? This always returns + * false for clang, since clang is "frozen" at GNUC 4.2. The __has_* + * feature-test macros should be used to detect clang functionality instead. */ +#define GCC_PREREQ(major, minor) \ + (!defined(__clang__) && !defined(__INTEL_COMPILER) && \ + (__GNUC__ > major || \ + (__GNUC__ == major && __GNUC_MINOR__ >= minor))) + +/* Feature-test macros defined by recent versions of clang. */ +#ifndef __has_attribute +# define __has_attribute(attribute) 0 +#endif +#ifndef __has_feature +# define __has_feature(feature) 0 +#endif +#ifndef __has_builtin +# define __has_builtin(builtin) 0 +#endif + +/* Declare that the annotated function should be exported from the shared + * library (or DLL). */ +#ifdef __WIN32__ +# define WIMLIBAPI __declspec(dllexport) #else -# define WIMLIBAPI -# define _always_inline_attribute inline -# define _format_attribute(type, format_str, args_start) -# define _cold_attribute -# define _packed_attribute -# define _malloc_attribute -# define _warn_unused_result_attribute -# define _aligned_attribute(size) -#endif /* __GNUC__ */ +# define WIMLIBAPI __attribute__((visibility("default"))) +#endif + +/* Declare that the annotated function should always be inlined. This might be + * desirable in highly tuned code, e.g. compression codecs. */ +#define forceinline inline __attribute__((always_inline)) + +/* Declare that the annotated function should *not* be inlined. */ +#define noinline __attribute__((noinline)) + +/* Functionally the same as 'noinline', but documents that the reason for not + * inlining is to prevent the annotated function from being inlined into a + * recursive function, thereby increasing its stack usage. */ +#define noinline_for_stack noinline + +/* Hint that the expression is usually true. */ +#define likely(expr) __builtin_expect(!!(expr), 1) + +/* Hint that the expression is usually false. */ +#define unlikely(expr) __builtin_expect(!!(expr), 0) + +/* Prefetch into L1 cache for read. */ +#define prefetchr(addr) __builtin_prefetch((addr), 0) + +/* Prefetch into L1 cache for write. */ +#define prefetchw(addr) __builtin_prefetch((addr), 1) + +/* Declare that the members of the annotated struct are tightly packed, and the + * struct itself may be misaligned. */ +#define _packed_attribute __attribute__((packed)) + +/* Declare that the annotated variable, or variables of the annotated type, are + * to be aligned on n-byte boundaries. */ +#define _aligned_attribute(n) __attribute__((aligned(n))) + +/* Declare that pointers to the annotated type may alias other pointers. */ +#define _may_alias_attribute __attribute__((may_alias)) + +/* Hint that the annotated function is rarely called. */ +#if GCC_PREREQ(4, 4) || __has_attribute(cold) +# define _cold_attribute __attribute__((cold)) +#else +# define _cold_attribute +#endif + +/* Hint that the annotated function is malloc-like: any non-null pointer it + * returns will not alias any pointer previously in use by the program. */ +#define _malloc_attribute __attribute__((malloc)) + +/* Hint that the annotated function takes a printf()-like format string and + * arguments. This is currently disabled on Windows because MinGW does not + * support this attribute on functions taking wide-character strings. */ +#ifdef __WIN32__ +# define _format_attribute(type, format_str, format_start) +#else +# define _format_attribute(type, format_str, format_start) \ + __attribute__((format(type, format_str, format_start))) +#endif + +/* Hint that the annotated function is intentionally not used. This might be + * the case if the function contains only static assertions. */ +#define _unused_attribute __attribute__((unused)) + +/* Endianness definitions. Either CPU_IS_BIG_ENDIAN or CPU_IS_LITTLE_ENDIAN is + * set to 1. The other is set to 0. Note that newer gcc supports + * __BYTE_ORDER__ for easily determining the endianness; older gcc doesn't. In + * the latter case we fall back to a configure-time check. */ +#ifdef __BYTE_ORDER__ +# define CPU_IS_BIG_ENDIAN (__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__) +#elif defined(HAVE_CONFIG_H) +# include "config.h" +# ifdef WORDS_BIGENDIAN +# define CPU_IS_BIG_ENDIAN 1 +# else +# define CPU_IS_BIG_ENDIAN 0 +# endif +#endif +#define CPU_IS_LITTLE_ENDIAN (!CPU_IS_BIG_ENDIAN) + +/* UNALIGNED_ACCESS_IS_FAST should be defined to 1 if unaligned memory accesses + * can be performed efficiently on the target platform. */ +#if defined(__x86_64__) || defined(__i386__) || defined(__ARM_FEATURE_UNALIGNED) +# define UNALIGNED_ACCESS_IS_FAST 1 +#else +# define UNALIGNED_ACCESS_IS_FAST 0 +#endif + +/* Get the type of the specified expression. */ +#define typeof __typeof__ + +/* Get the minimum of two variables, without multiple evaluation. */ +#ifndef min +# define min(a, b) ({ typeof(a) _a = (a); typeof(b) _b = (b); \ + (_a < _b) ? _a : _b; }) +#endif + +/* Get the maximum of two variables, without multiple evaluation. */ +#ifndef max +# define max(a, b) ({ typeof(a) _a = (a); typeof(b) _b = (b); \ + (_a > _b) ? _a : _b; }) +#endif + +/* Swap the values of two variables, without multiple evaluation. */ +#ifndef swap +# define swap(a, b) ({ typeof(a) _a = (a); (a) = (b); (b) = _a; }) +#endif + +/* (Optional) Efficiently swap the bytes of a 16-bit integer. */ +#if GCC_PREREQ(4, 8) || __has_builtin(__builtin_bswap16) +# define compiler_bswap16 __builtin_bswap16 +#endif + +/* (Optional) Efficiently swap the bytes of a 32-bit integer. */ +#if GCC_PREREQ(4, 3) || __has_builtin(__builtin_bswap32) +# define compiler_bswap32 __builtin_bswap32 +#endif + +/* (Optional) Efficiently swap the bytes of a 64-bit integer. */ +#if GCC_PREREQ(4, 3) || __has_builtin(__builtin_bswap64) +# define compiler_bswap64 __builtin_bswap64 +#endif + +/* (Optional) Find Last Set bit and Find First Set bit macros. */ +#define compiler_bsr32(n) (31 - __builtin_clz(n)) +#define compiler_bsr64(n) (63 - __builtin_clzll(n)) +#define compiler_bsf32(n) __builtin_ctz(n) +#define compiler_bsf64(n) __builtin_ctzll(n) + +/* Optional definitions for checking with 'sparse'. */ +#ifdef __CHECKER__ +# define _bitwise_attr __attribute__((bitwise)) +# define _force_attr __attribute__((force)) +#else +# define _bitwise_attr +# define _force_attr +#endif + +/* STATIC_ASSERT() - verify the truth of an expression at compilation time. */ +#if __STDC_VERSION__ >= 201112L +# define STATIC_ASSERT(expr) _Static_assert((expr), "") +#else +# define STATIC_ASSERT(expr) ((void)sizeof(char[1 - 2 * !(expr)])) +#endif + +/* STATIC_ASSERT_ZERO() - verify the truth of an expression at compilation time + * and also produce a result of value '0' to be used in constant expressions */ +#define STATIC_ASSERT_ZERO(expr) ((int)sizeof(char[-!(expr)])) + +#define CONCAT_IMPL(s1, s2) s1##s2 + +/* CONCAT() - concatenate two tokens at preprocessing time. */ +#define CONCAT(s1, s2) CONCAT_IMPL(s1, s2) #endif /* _WIMLIB_COMPILER_H */