diff options
Diffstat (limited to 'Include/pymacro.h')
| -rw-r--r-- | Include/pymacro.h | 68 |
1 files changed, 66 insertions, 2 deletions
diff --git a/Include/pymacro.h b/Include/pymacro.h index a82f347866e..b2886ddac5d 100644 --- a/Include/pymacro.h +++ b/Include/pymacro.h @@ -23,6 +23,69 @@ # define static_assert _Static_assert #endif + +// _Py_ALIGNED_DEF(N, T): Define a variable/member with increased alignment +// +// `N`: the desired minimum alignment, an integer literal, number of bytes +// `T`: the type of the defined variable +// (or a type with at least the defined variable's alignment) +// +// May not be used on a struct definition. +// +// Standards/compiler support for `alignas` alternatives: +// - `alignas` is a keyword in C23 and C++11. +// - `_Alignas` is a keyword in C11 +// - GCC & clang has __attribute__((aligned)) +// (use that for older standards in pedantic mode) +// - MSVC has __declspec(align) +// - `_Alignas` is common C compiler extension +// Older compilers may name `alignas` differently; to allow compilation on such +// unsupported platforms, we don't redefine _Py_ALIGNED_DEF if it's already +// defined. Note that defining it wrong (including defining it to nothing) will +// cause ABI incompatibilities. +// +// Behavior of `alignas` alternatives: +// - `alignas` & `_Alignas`: +// - Can be used multiple times; the greatest alignment applies. +// - It is an *error* if the combined effect of all `alignas` modifiers would +// decrease the alignment. +// - Takes types or numbers. +// - May not be used on a struct definition, unless also defining a variable. +// - `__declspec(align)`: +// - Has no effect if it would decrease alignment. +// - Only takes an integer literal. +// - May be used on struct or variable definitions. +// However, when defining both the struct and the variable at once, +// `declspec(aligned)` causes compiler warning 5274 and possible ABI +// incompatibility. +// - ` __attribute__((aligned))`: +// - Has no effect if it would decrease alignment. +// - Takes types or numbers +// - May be used on struct or variable definitions. +#ifndef _Py_ALIGNED_DEF +# ifdef __cplusplus +# if __cplusplus >= 201103L +# define _Py_ALIGNED_DEF(N, T) alignas(N) alignas(T) T +# elif defined(__GNUC__) || defined(__clang__) +# define _Py_ALIGNED_DEF(N, T) __attribute__((aligned(N))) T +# elif defined(_MSC_VER) +# define _Py_ALIGNED_DEF(N, T) __declspec(align(N)) T +# else +# define _Py_ALIGNED_DEF(N, T) alignas(N) alignas(T) T +# endif +# elif defined(_MSC_VER) +# define _Py_ALIGNED_DEF(N, T) __declspec(align(N)) T +# elif defined(__STDC_VERSION__) && __STDC_VERSION__ >= 202311L +# define _Py_ALIGNED_DEF(N, T) alignas(N) alignas(T) T +# elif defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L +# define _Py_ALIGNED_DEF(N, T) _Alignas(N) _Alignas(T) T +# elif (defined(__GNUC__) || defined(__clang__)) +# define _Py_ALIGNED_DEF(N, T) __attribute__((aligned(N))) T +# else +# define _Py_ALIGNED_DEF(N, T) _Alignas(N) _Alignas(T) T +# endif +#endif + /* Minimum value between x and y */ #define Py_MIN(x, y) (((x) > (y)) ? (y) : (x)) @@ -190,12 +253,13 @@ // "comparison of unsigned expression in '< 0' is always false". #define _Py_IS_TYPE_SIGNED(type) ((type)(-1) <= 0) -#if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= 0x030E0000 // 3.14 // Version helpers. These are primarily macros, but have exported equivalents. +#define _Py_PACK_VERSION(X, Y) _Py_PACK_FULL_VERSION(X, Y, 0, 0, 0) +#if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= _Py_PACK_VERSION(3, 14) PyAPI_FUNC(uint32_t) Py_PACK_FULL_VERSION(int x, int y, int z, int level, int serial); PyAPI_FUNC(uint32_t) Py_PACK_VERSION(int x, int y); #define Py_PACK_FULL_VERSION _Py_PACK_FULL_VERSION -#define Py_PACK_VERSION(X, Y) Py_PACK_FULL_VERSION(X, Y, 0, 0, 0) +#define Py_PACK_VERSION _Py_PACK_VERSION #endif // Py_LIMITED_API < 3.14 |