mirror of
https://github.com/apple/swift.git
synced 2026-11-04 00:12:11 +01:00
Doug Gregor
5a7329e431
Introduce EMBEDDED_SWIFT_MUTEX_NUM_WORDS to capture the number of words that will be allocated within Synchronization.Mutex to store a platform mutex. The previously-picked value is too small for some platforms (32-bit watchOS needs at least 11) and is being copied into sources in several different places. Centralizing that value let's us customize it further, both in the platform header and through the command line. Part of rdar://181952065.
83 lines
2.7 KiB
C
83 lines
2.7 KiB
C
/*===------ EmbeddedPlatformMultiThreadedPOSIX.c -----------------*- C -*-===*
|
|
*
|
|
* This source file is part of the Swift.org open source project
|
|
*
|
|
* Copyright (c) 2026 Apple Inc. and the Swift project authors
|
|
* Licensed under Apache License v2.0 with Runtime Library Exception
|
|
*
|
|
* See https://swift.org/LICENSE.txt for license information
|
|
* See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
|
|
*
|
|
*===----------------------------------------------------------------------===*
|
|
*
|
|
* A multi-threaded implementation of the Embedded Swift platform mutex hooks
|
|
* on top of `pthread_mutex_t`. The `pthread_mutex_t` is constructed directly
|
|
* in the eight pointer-sized words of caller-owned storage that the platform
|
|
* layer provides — 64 bytes on 64-bit targets, which fits every currently
|
|
* supported `pthread_mutex_t` (40 bytes on glibc LP64, 56 bytes on Darwin
|
|
* LP64).
|
|
*
|
|
*===----------------------------------------------------------------------===*/
|
|
|
|
|
|
#include "swift/EmbeddedPlatform.h"
|
|
|
|
#include <pthread.h>
|
|
|
|
#if __STDC_VERSION__ >= 201112L
|
|
_Static_assert(sizeof(pthread_mutex_t) <= EMBEDDED_SWIFT_MUTEX_NUM_WORDS * sizeof(void *),
|
|
"pthread_mutex_t does not fit in the Embedded Swift Platform "
|
|
"mutex storage (8 pointer-sized words)");
|
|
_Static_assert(_Alignof(pthread_mutex_t) <= _Alignof(void *),
|
|
"pthread_mutex_t requires stronger alignment than the Embedded "
|
|
"Swift Platform mutex storage provides");
|
|
#endif
|
|
|
|
static void trap_if(int failed) {
|
|
if (failed) {
|
|
#if __has_builtin(__builtin_trap)
|
|
__builtin_trap();
|
|
#else
|
|
*(volatile int*)0x11 = 0;
|
|
#endif
|
|
}
|
|
}
|
|
|
|
void _swift_mutex_init(void *mutex, swift_mutex_flags_t flags) {
|
|
int type;
|
|
if (flags & SWIFT_MUTEX_RECURSIVE) {
|
|
type = PTHREAD_MUTEX_RECURSIVE;
|
|
} else if (flags & SWIFT_MUTEX_CHECKED) {
|
|
type = PTHREAD_MUTEX_ERRORCHECK;
|
|
} else {
|
|
type = PTHREAD_MUTEX_NORMAL;
|
|
}
|
|
|
|
if (type == PTHREAD_MUTEX_NORMAL) {
|
|
trap_if(pthread_mutex_init((pthread_mutex_t *)mutex, NULL) != 0);
|
|
return;
|
|
}
|
|
|
|
pthread_mutexattr_t attr;
|
|
trap_if(pthread_mutexattr_init(&attr) != 0);
|
|
trap_if(pthread_mutexattr_settype(&attr, type) != 0);
|
|
trap_if(pthread_mutex_init((pthread_mutex_t *)mutex, &attr) != 0);
|
|
(void)pthread_mutexattr_destroy(&attr);
|
|
}
|
|
|
|
void _swift_mutex_destroy(void *mutex) {
|
|
trap_if(pthread_mutex_destroy((pthread_mutex_t *)mutex) != 0);
|
|
}
|
|
|
|
void _swift_mutex_lock(void *mutex) {
|
|
trap_if(pthread_mutex_lock((pthread_mutex_t *)mutex) != 0);
|
|
}
|
|
|
|
void _swift_mutex_unlock(void *mutex) {
|
|
trap_if(pthread_mutex_unlock((pthread_mutex_t *)mutex) != 0);
|
|
}
|
|
|
|
__swift_ptrdiff_t _swift_mutex_tryLock(void *mutex) {
|
|
return pthread_mutex_trylock((pthread_mutex_t *)mutex) == 0 ? 1 : 0;
|
|
}
|