1 #ifndef Py_PYMACRO_H 2 #define Py_PYMACRO_H 3 4 // gh-91782: On FreeBSD 12, if the _POSIX_C_SOURCE and _XOPEN_SOURCE macros are 5 // defined, <sys/cdefs.h> disables C11 support and <assert.h> does not define 6 // the static_assert() macro. 7 // https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=255290 8 // 9 // macOS <= 10.10 doesn't define static_assert in assert.h at all despite 10 // having C11 compiler support. 11 // 12 // static_assert is defined in glibc from version 2.16. Compiler support for 13 // the C11 _Static_assert keyword is in gcc >= 4.6. 14 // 15 // MSVC makes static_assert a keyword in C11-17, contrary to the standards. 16 // 17 // In C++11 and C2x, static_assert is a keyword, redefining is undefined 18 // behaviour. So only define if building as C, not C++ (if __cplusplus is 19 // not defined), and only for C11-17. 20 #if !defined(static_assert) && (defined(__GNUC__) || defined(__clang__)) \ 21 && !defined(__cplusplus) && defined(__STDC_VERSION__) \ 22 && __STDC_VERSION__ >= 201112L && __STDC_VERSION__ <= 201710L 23 # define static_assert _Static_assert 24 #endif 25 26 /* Minimum value between x and y */ 27 #define Py_MIN(x, y) (((x) > (y)) ? (y) : (x)) 28 29 /* Maximum value between x and y */ 30 #define Py_MAX(x, y) (((x) > (y)) ? (x) : (y)) 31 32 /* Absolute value of the number x */ 33 #define Py_ABS(x) ((x) < 0 ? -(x) : (x)) 34 35 #define _Py_XSTRINGIFY(x) #x 36 37 /* Convert the argument to a string. For example, Py_STRINGIFY(123) is replaced 38 with "123" by the preprocessor. Defines are also replaced by their value. 39 For example Py_STRINGIFY(__LINE__) is replaced by the line number, not 40 by "__LINE__". */ 41 #define Py_STRINGIFY(x) _Py_XSTRINGIFY(x) 42 43 /* Get the size of a structure member in bytes */ 44 #define Py_MEMBER_SIZE(type, member) sizeof(((type *)0)->member) 45 46 /* Argument must be a char or an int in [-128, 127] or [0, 255]. */ 47 #define Py_CHARMASK(c) ((unsigned char)((c) & 0xff)) 48 49 #if (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L \ 50 && !defined(__cplusplus)) 51 # define Py_BUILD_ASSERT_EXPR(cond) \ 52 ((void)sizeof(struct { int dummy; _Static_assert(cond, #cond); }), \ 53 0) 54 #else 55 /* Assert a build-time dependency, as an expression. 56 * 57 * Your compile will fail if the condition isn't true, or can't be evaluated 58 * by the compiler. This can be used in an expression: its value is 0. 59 * 60 * Example: 61 * 62 * #define foo_to_char(foo) \ 63 * ((char *)(foo) \ 64 * + Py_BUILD_ASSERT_EXPR(offsetof(struct foo, string) == 0)) 65 * 66 * Written by Rusty Russell, public domain, http://ccodearchive.net/ 67 */ 68 # define Py_BUILD_ASSERT_EXPR(cond) \ 69 (sizeof(char [1 - 2*!(cond)]) - 1) 70 #endif 71 72 #if ((defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L) \ 73 || (defined(__cplusplus) && __cplusplus >= 201103L)) 74 // Use static_assert() on C11 and newer 75 # define Py_BUILD_ASSERT(cond) \ 76 do { \ 77 static_assert((cond), #cond); \ 78 } while (0) 79 #else 80 # define Py_BUILD_ASSERT(cond) \ 81 do { \ 82 (void)Py_BUILD_ASSERT_EXPR(cond); \ 83 } while(0) 84 #endif 85 86 /* Get the number of elements in a visible array 87 88 This does not work on pointers, or arrays declared as [], or function 89 parameters. With correct compiler support, such usage will cause a build 90 error (see Py_BUILD_ASSERT_EXPR). 91 92 Written by Rusty Russell, public domain, http://ccodearchive.net/ 93 94 Requires at GCC 3.1+ */ 95 #if (defined(__GNUC__) && !defined(__STRICT_ANSI__) && \ 96 (((__GNUC__ == 3) && (__GNUC_MINOR__ >= 1)) || (__GNUC__ >= 4))) 97 /* Two gcc extensions. 98 &a[0] degrades to a pointer: a different type from an array */ 99 #define Py_ARRAY_LENGTH(array) \ 100 (sizeof(array) / sizeof((array)[0]) \ 101 + Py_BUILD_ASSERT_EXPR(!__builtin_types_compatible_p(typeof(array), \ 102 typeof(&(array)[0])))) 103 #else 104 #define Py_ARRAY_LENGTH(array) \ 105 (sizeof(array) / sizeof((array)[0])) 106 #endif 107 108 109 /* Define macros for inline documentation. */ 110 #define PyDoc_VAR(name) static const char name[] 111 #define PyDoc_STRVAR(name,str) PyDoc_VAR(name) = PyDoc_STR(str) 112 #ifdef WITH_DOC_STRINGS 113 #define PyDoc_STR(str) str 114 #else 115 #define PyDoc_STR(str) "" 116 #endif 117 118 /* Below "a" is a power of 2. */ 119 /* Round down size "n" to be a multiple of "a". */ 120 #define _Py_SIZE_ROUND_DOWN(n, a) ((size_t)(n) & ~(size_t)((a) - 1)) 121 /* Round up size "n" to be a multiple of "a". */ 122 #define _Py_SIZE_ROUND_UP(n, a) (((size_t)(n) + \ 123 (size_t)((a) - 1)) & ~(size_t)((a) - 1)) 124 /* Round pointer "p" down to the closest "a"-aligned address <= "p". */ 125 #define _Py_ALIGN_DOWN(p, a) ((void *)((uintptr_t)(p) & ~(uintptr_t)((a) - 1))) 126 /* Round pointer "p" up to the closest "a"-aligned address >= "p". */ 127 #define _Py_ALIGN_UP(p, a) ((void *)(((uintptr_t)(p) + \ 128 (uintptr_t)((a) - 1)) & ~(uintptr_t)((a) - 1))) 129 /* Check if pointer "p" is aligned to "a"-bytes boundary. */ 130 #define _Py_IS_ALIGNED(p, a) (!((uintptr_t)(p) & (uintptr_t)((a) - 1))) 131 132 /* Use this for unused arguments in a function definition to silence compiler 133 * warnings. Example: 134 * 135 * int func(int a, int Py_UNUSED(b)) { return a; } 136 */ 137 #if defined(__GNUC__) || defined(__clang__) 138 # define Py_UNUSED(name) _unused_ ## name __attribute__((unused)) 139 #elif defined(_MSC_VER) 140 // Disable warning C4100: unreferenced formal parameter, 141 // declare the parameter, 142 // restore old compiler warnings. 143 # define Py_UNUSED(name) \ 144 __pragma(warning(push)) \ 145 __pragma(warning(suppress: 4100)) \ 146 _unused_ ## name \ 147 __pragma(warning(pop)) 148 #else 149 # define Py_UNUSED(name) _unused_ ## name 150 #endif 151 152 #if defined(RANDALL_WAS_HERE) 153 # define Py_UNREACHABLE() \ 154 Py_FatalError( \ 155 "If you're seeing this, the code is in what I thought was\n" \ 156 "an unreachable state.\n\n" \ 157 "I could give you advice for what to do, but honestly, why\n" \ 158 "should you trust me? I clearly screwed this up. I'm writing\n" \ 159 "a message that should never appear, yet I know it will\n" \ 160 "probably appear someday.\n\n" \ 161 "On a deep level, I know I'm not up to this task.\n" \ 162 "I'm so sorry.\n" \ 163 "https://xkcd.com/2200") 164 #elif defined(Py_DEBUG) 165 # define Py_UNREACHABLE() \ 166 Py_FatalError( \ 167 "We've reached an unreachable state. Anything is possible.\n" \ 168 "The limits were in our heads all along. Follow your dreams.\n" \ 169 "https://xkcd.com/2200") 170 #elif defined(__GNUC__) && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 5)) 171 # define Py_UNREACHABLE() __builtin_unreachable() 172 #elif defined(__clang__) || defined(__INTEL_COMPILER) 173 # define Py_UNREACHABLE() __builtin_unreachable() 174 #elif defined(_MSC_VER) 175 # define Py_UNREACHABLE() __assume(0) 176 #else 177 # define Py_UNREACHABLE() \ 178 Py_FatalError("Unreachable C code path reached") 179 #endif 180 181 #define _Py_CONTAINER_OF(ptr, type, member) \ 182 (type*)((char*)ptr - offsetof(type, member)) 183 184 // Prevent using an expression as a l-value. 185 // For example, "int x; _Py_RVALUE(x) = 1;" fails with a compiler error. 186 #define _Py_RVALUE(EXPR) ((void)0, (EXPR)) 187 188 // Return non-zero if the type is signed, return zero if it's unsigned. 189 // Use "<= 0" rather than "< 0" to prevent the compiler warning: 190 // "comparison of unsigned expression in '< 0' is always false". 191 #define _Py_IS_TYPE_SIGNED(type) ((type)(-1) <= 0) 192 193 #endif /* Py_PYMACRO_H */ 194