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/*
* Copyright 2011 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "SkThread.h"
#include "SkTLS.h"
#include <pthread.h>
#include <errno.h>
#ifndef SK_BUILD_FOR_ANDROID
/**
We prefer the GCC intrinsic implementation of the atomic operations over the
SkMutex-based implementation. The SkMutex version suffers from static
destructor ordering problems.
Note clang also defines the GCC version macros and implements the intrinsics.
TODO: Verify that gcc-style __sync_* intrinsics work on ARM
According to this the intrinsics are supported on ARM in LLVM 2.7+
http://llvm.org/releases/2.7/docs/ReleaseNotes.html
*/
#if (__GNUC__ == 4 && __GNUC_MINOR__ >= 1) || __GNUC__ > 4
#if (defined(__x86_64) || defined(__i386__))
#define GCC_INTRINSIC
#endif
#endif
#if defined(GCC_INTRINSIC)
int32_t sk_atomic_inc(int32_t* addr)
{
return __sync_fetch_and_add(addr, 1);
}
int32_t sk_atomic_dec(int32_t* addr)
{
return __sync_fetch_and_add(addr, -1);
}
void sk_membar_aquire__after_atomic_dec() { }
int32_t sk_atomic_conditional_inc(int32_t* addr)
{
int32_t value = *addr;
while (true) {
if (value == 0) {
return 0;
}
int32_t before = __sync_val_compare_and_swap(addr, value, value + 1);
if (before == value) {
return value;
} else {
value = before;
}
}
}
void sk_membar_aquire__after_atomic_conditional_inc() { }
#else
SkMutex gAtomicMutex;
int32_t sk_atomic_inc(int32_t* addr)
{
SkAutoMutexAcquire ac(gAtomicMutex);
int32_t value = *addr;
*addr = value + 1;
return value;
}
int32_t sk_atomic_dec(int32_t* addr)
{
SkAutoMutexAcquire ac(gAtomicMutex);
int32_t value = *addr;
*addr = value - 1;
return value;
}
void sk_membar_aquire__after_atomic_dec() { }
int32_t sk_atomic_conditional_inc(int32_t* addr)
{
SkAutoMutexAcquire ac(gAtomicMutex);
int32_t value = *addr;
if (value != 0) ++*addr;
return value;
}
void sk_membar_aquire__after_atomic_conditional_inc() { }
#endif
#endif // SK_BUILD_FOR_ANDROID
//////////////////////////////////////////////////////////////////////////////
static void print_pthread_error(int status) {
switch (status) {
case 0: // success
break;
case EINVAL:
SkDebugf("pthread error [%d] EINVAL\n", status);
break;
case EBUSY:
SkDebugf("pthread error [%d] EBUSY\n", status);
break;
default:
SkDebugf("pthread error [%d] unknown\n", status);
break;
}
}
#ifdef SK_USE_POSIX_THREADS
SkMutex::SkMutex() {
int status;
status = pthread_mutex_init(&fMutex, NULL);
if (status != 0) {
print_pthread_error(status);
SkASSERT(0 == status);
}
}
SkMutex::~SkMutex() {
int status = pthread_mutex_destroy(&fMutex);
// only report errors on non-global mutexes
if (status != 0) {
print_pthread_error(status);
SkASSERT(0 == status);
}
}
#else // !SK_USE_POSIX_THREADS
SkMutex::SkMutex() {
if (sizeof(pthread_mutex_t) > sizeof(fStorage)) {
SkDEBUGF(("pthread mutex size = %d\n", sizeof(pthread_mutex_t)));
SkDEBUGFAIL("mutex storage is too small");
}
int status;
pthread_mutexattr_t attr;
status = pthread_mutexattr_init(&attr);
print_pthread_error(status);
SkASSERT(0 == status);
status = pthread_mutex_init((pthread_mutex_t*)fStorage, &attr);
print_pthread_error(status);
SkASSERT(0 == status);
}
SkMutex::~SkMutex() {
int status = pthread_mutex_destroy((pthread_mutex_t*)fStorage);
#if 0
// only report errors on non-global mutexes
if (!fIsGlobal) {
print_pthread_error(status);
SkASSERT(0 == status);
}
#endif
}
void SkMutex::acquire() {
int status = pthread_mutex_lock((pthread_mutex_t*)fStorage);
print_pthread_error(status);
SkASSERT(0 == status);
}
void SkMutex::release() {
int status = pthread_mutex_unlock((pthread_mutex_t*)fStorage);
print_pthread_error(status);
SkASSERT(0 == status);
}
#endif // !SK_USE_POSIX_THREADS
///////////////////////////////////////////////////////////////////////////////
static pthread_key_t gSkTLSKey;
static pthread_once_t gSkTLSKey_Once = PTHREAD_ONCE_INIT;
static void sk_tls_make_key() {
(void)pthread_key_create(&gSkTLSKey, SkTLS::Destructor);
}
void* SkTLS::PlatformGetSpecific(bool forceCreateTheSlot) {
// should we use forceCreateTheSlot to potentially skip calling pthread_once
// and just return NULL if we've never been called with
// forceCreateTheSlot==true ?
(void)pthread_once(&gSkTLSKey_Once, sk_tls_make_key);
return pthread_getspecific(gSkTLSKey);
}
void SkTLS::PlatformSetSpecific(void* ptr) {
(void)pthread_setspecific(gSkTLSKey, ptr);
}
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