mirror of
https://github.com/python/cpython.git
synced 2024-11-22 13:28:21 +01:00
441affc9e7
The `--disable-gil` builds occasionally need to pause all but one thread. Some examples include: * Cyclic garbage collection, where this is often called a "stop the world event" * Before calling `fork()`, to ensure a consistent state for internal data structures * During interpreter shutdown, to ensure that daemon threads aren't accessing Python objects This adds the following functions to implement global and per-interpreter pauses: * `_PyEval_StopTheWorldAll()` and `_PyEval_StartTheWorldAll()` (for the global runtime) * `_PyEval_StopTheWorld()` and `_PyEval_StartTheWorld()` (per-interpreter) (The function names may change.) These functions are no-ops outside of the `--disable-gil` build.
176 lines
6.6 KiB
C
176 lines
6.6 KiB
C
#ifndef Py_PYMACRO_H
|
|
#define Py_PYMACRO_H
|
|
|
|
// gh-91782: On FreeBSD 12, if the _POSIX_C_SOURCE and _XOPEN_SOURCE macros are
|
|
// defined, <sys/cdefs.h> disables C11 support and <assert.h> does not define
|
|
// the static_assert() macro.
|
|
// https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=255290
|
|
//
|
|
// macOS <= 10.10 doesn't define static_assert in assert.h at all despite
|
|
// having C11 compiler support.
|
|
//
|
|
// static_assert is defined in glibc from version 2.16. Compiler support for
|
|
// the C11 _Static_assert keyword is in gcc >= 4.6.
|
|
//
|
|
// MSVC makes static_assert a keyword in C11-17, contrary to the standards.
|
|
//
|
|
// In C++11 and C2x, static_assert is a keyword, redefining is undefined
|
|
// behaviour. So only define if building as C (if __STDC_VERSION__ is defined),
|
|
// not C++, and only for C11-17.
|
|
#if !defined(static_assert) && (defined(__GNUC__) || defined(__clang__)) \
|
|
&& defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L \
|
|
&& __STDC_VERSION__ <= 201710L
|
|
# define static_assert _Static_assert
|
|
#endif
|
|
|
|
/* Minimum value between x and y */
|
|
#define Py_MIN(x, y) (((x) > (y)) ? (y) : (x))
|
|
|
|
/* Maximum value between x and y */
|
|
#define Py_MAX(x, y) (((x) > (y)) ? (x) : (y))
|
|
|
|
/* Absolute value of the number x */
|
|
#define Py_ABS(x) ((x) < 0 ? -(x) : (x))
|
|
|
|
#define _Py_XSTRINGIFY(x) #x
|
|
|
|
/* Convert the argument to a string. For example, Py_STRINGIFY(123) is replaced
|
|
with "123" by the preprocessor. Defines are also replaced by their value.
|
|
For example Py_STRINGIFY(__LINE__) is replaced by the line number, not
|
|
by "__LINE__". */
|
|
#define Py_STRINGIFY(x) _Py_XSTRINGIFY(x)
|
|
|
|
/* Get the size of a structure member in bytes */
|
|
#define Py_MEMBER_SIZE(type, member) sizeof(((type *)0)->member)
|
|
|
|
/* Argument must be a char or an int in [-128, 127] or [0, 255]. */
|
|
#define Py_CHARMASK(c) ((unsigned char)((c) & 0xff))
|
|
|
|
/* Assert a build-time dependency, as an expression.
|
|
|
|
Your compile will fail if the condition isn't true, or can't be evaluated
|
|
by the compiler. This can be used in an expression: its value is 0.
|
|
|
|
Example:
|
|
|
|
#define foo_to_char(foo) \
|
|
((char *)(foo) \
|
|
+ Py_BUILD_ASSERT_EXPR(offsetof(struct foo, string) == 0))
|
|
|
|
Written by Rusty Russell, public domain, http://ccodearchive.net/ */
|
|
#define Py_BUILD_ASSERT_EXPR(cond) \
|
|
(sizeof(char [1 - 2*!(cond)]) - 1)
|
|
|
|
#define Py_BUILD_ASSERT(cond) do { \
|
|
(void)Py_BUILD_ASSERT_EXPR(cond); \
|
|
} while(0)
|
|
|
|
/* Get the number of elements in a visible array
|
|
|
|
This does not work on pointers, or arrays declared as [], or function
|
|
parameters. With correct compiler support, such usage will cause a build
|
|
error (see Py_BUILD_ASSERT_EXPR).
|
|
|
|
Written by Rusty Russell, public domain, http://ccodearchive.net/
|
|
|
|
Requires at GCC 3.1+ */
|
|
#if (defined(__GNUC__) && !defined(__STRICT_ANSI__) && \
|
|
(((__GNUC__ == 3) && (__GNUC_MINOR__ >= 1)) || (__GNUC__ >= 4)))
|
|
/* Two gcc extensions.
|
|
&a[0] degrades to a pointer: a different type from an array */
|
|
#define Py_ARRAY_LENGTH(array) \
|
|
(sizeof(array) / sizeof((array)[0]) \
|
|
+ Py_BUILD_ASSERT_EXPR(!__builtin_types_compatible_p(typeof(array), \
|
|
typeof(&(array)[0]))))
|
|
#else
|
|
#define Py_ARRAY_LENGTH(array) \
|
|
(sizeof(array) / sizeof((array)[0]))
|
|
#endif
|
|
|
|
|
|
/* Define macros for inline documentation. */
|
|
#define PyDoc_VAR(name) static const char name[]
|
|
#define PyDoc_STRVAR(name,str) PyDoc_VAR(name) = PyDoc_STR(str)
|
|
#ifdef WITH_DOC_STRINGS
|
|
#define PyDoc_STR(str) str
|
|
#else
|
|
#define PyDoc_STR(str) ""
|
|
#endif
|
|
|
|
/* Below "a" is a power of 2. */
|
|
/* Round down size "n" to be a multiple of "a". */
|
|
#define _Py_SIZE_ROUND_DOWN(n, a) ((size_t)(n) & ~(size_t)((a) - 1))
|
|
/* Round up size "n" to be a multiple of "a". */
|
|
#define _Py_SIZE_ROUND_UP(n, a) (((size_t)(n) + \
|
|
(size_t)((a) - 1)) & ~(size_t)((a) - 1))
|
|
/* Round pointer "p" down to the closest "a"-aligned address <= "p". */
|
|
#define _Py_ALIGN_DOWN(p, a) ((void *)((uintptr_t)(p) & ~(uintptr_t)((a) - 1)))
|
|
/* Round pointer "p" up to the closest "a"-aligned address >= "p". */
|
|
#define _Py_ALIGN_UP(p, a) ((void *)(((uintptr_t)(p) + \
|
|
(uintptr_t)((a) - 1)) & ~(uintptr_t)((a) - 1)))
|
|
/* Check if pointer "p" is aligned to "a"-bytes boundary. */
|
|
#define _Py_IS_ALIGNED(p, a) (!((uintptr_t)(p) & (uintptr_t)((a) - 1)))
|
|
|
|
/* Use this for unused arguments in a function definition to silence compiler
|
|
* warnings. Example:
|
|
*
|
|
* int func(int a, int Py_UNUSED(b)) { return a; }
|
|
*/
|
|
#if defined(__GNUC__) || defined(__clang__)
|
|
# define Py_UNUSED(name) _unused_ ## name __attribute__((unused))
|
|
#elif defined(_MSC_VER)
|
|
// Disable warning C4100: unreferenced formal parameter,
|
|
// declare the parameter,
|
|
// restore old compiler warnings.
|
|
# define Py_UNUSED(name) \
|
|
__pragma(warning(push)) \
|
|
__pragma(warning(suppress: 4100)) \
|
|
_unused_ ## name \
|
|
__pragma(warning(pop))
|
|
#else
|
|
# define Py_UNUSED(name) _unused_ ## name
|
|
#endif
|
|
|
|
#if defined(RANDALL_WAS_HERE)
|
|
# define Py_UNREACHABLE() \
|
|
Py_FatalError( \
|
|
"If you're seeing this, the code is in what I thought was\n" \
|
|
"an unreachable state.\n\n" \
|
|
"I could give you advice for what to do, but honestly, why\n" \
|
|
"should you trust me? I clearly screwed this up. I'm writing\n" \
|
|
"a message that should never appear, yet I know it will\n" \
|
|
"probably appear someday.\n\n" \
|
|
"On a deep level, I know I'm not up to this task.\n" \
|
|
"I'm so sorry.\n" \
|
|
"https://xkcd.com/2200")
|
|
#elif defined(Py_DEBUG)
|
|
# define Py_UNREACHABLE() \
|
|
Py_FatalError( \
|
|
"We've reached an unreachable state. Anything is possible.\n" \
|
|
"The limits were in our heads all along. Follow your dreams.\n" \
|
|
"https://xkcd.com/2200")
|
|
#elif defined(__GNUC__) && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 5))
|
|
# define Py_UNREACHABLE() __builtin_unreachable()
|
|
#elif defined(__clang__) || defined(__INTEL_COMPILER)
|
|
# define Py_UNREACHABLE() __builtin_unreachable()
|
|
#elif defined(_MSC_VER)
|
|
# define Py_UNREACHABLE() __assume(0)
|
|
#else
|
|
# define Py_UNREACHABLE() \
|
|
Py_FatalError("Unreachable C code path reached")
|
|
#endif
|
|
|
|
#define _Py_CONTAINER_OF(ptr, type, member) \
|
|
(type*)((char*)ptr - offsetof(type, member))
|
|
|
|
// Prevent using an expression as a l-value.
|
|
// For example, "int x; _Py_RVALUE(x) = 1;" fails with a compiler error.
|
|
#define _Py_RVALUE(EXPR) ((void)0, (EXPR))
|
|
|
|
// Return non-zero if the type is signed, return zero if it's unsigned.
|
|
// Use "<= 0" rather than "< 0" to prevent the compiler warning:
|
|
// "comparison of unsigned expression in '< 0' is always false".
|
|
#define _Py_IS_TYPE_SIGNED(type) ((type)(-1) <= 0)
|
|
|
|
#endif /* Py_PYMACRO_H */
|