+/*
+ * compiler.h
+ *
+ * Compiler-specific definitions. Currently, only GCC and clang are supported.
+ *
+ * Copyright 2022 Eric Biggers
+ *
+ * Permission is hereby granted, free of charge, to any person
+ * obtaining a copy of this software and associated documentation
+ * files (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following
+ * conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+ * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+ * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ */
+
#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)))
-# define likely(x) __builtin_expect(!!(x), 1)
-# define unlikely(x) __builtin_expect(!!(x), 0)
-# define inline inline __attribute__((always_inline))
-# define prefetch(x) __builtin_prefetch(x)
+/* 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 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)
+
+/* 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
+
+/* Endianness definitions. Either CPU_IS_BIG_ENDIAN() or CPU_IS_LITTLE_ENDIAN()
+ * evaluates to 1. The other evaluates 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) || defined(__powerpc64__)
+# define UNALIGNED_ACCESS_IS_FAST 1
+#else
+# define UNALIGNED_ACCESS_IS_FAST 0
+#endif
+
+/* Get the minimum of two variables, without multiple evaluation. */
+#undef min
+#define min(a, b) ({ typeof(a) _a = (a); typeof(b) _b = (b); \
+ (_a < _b) ? _a : _b; })
+#undef MIN
+#define MIN(a, b) min((a), (b))
+
+/* Get the maximum of two variables, without multiple evaluation. */
+#undef max
+#define max(a, b) ({ typeof(a) _a = (a); typeof(b) _b = (b); \
+ (_a > _b) ? _a : _b; })
+#undef MAX
+#define MAX(a, b) max((a), (b))
+
+/* Get the maximum of three variables, without multiple evaluation. */
+#undef max3
+#define max3(a, b, c) max(max((a), (b)), (c))
+
+/* Swap the values of two variables, without multiple evaluation. */
+#ifndef swap
+# define swap(a, b) ({ typeof(a) _a = (a); (a) = (b); (b) = _a; })
+#endif
+#define SWAP(a, b) swap((a), (b))
+
+/* 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. */
+#ifdef __CHECKER__
+# define STATIC_ASSERT(expr)
+#elif __STDC_VERSION__ >= 201112L
+# define STATIC_ASSERT(expr) _Static_assert((expr), "")
#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)
-# define likely(x) (x)
-# define unlikely(x) (x)
-# define prefetch(x)
-#endif /* __GNUC__ */
+# 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 */
git://wimlib.net / wimlib / blobdiff