#pragma once
#include <c10/macros/Macros.h>
/**
* Android versions with libgnustl incorrectly handle thread_local C++
* qualifier with composite types. NDK up to r17 version is affected.
*
* (A fix landed on Jun 4 2018:
* https://android-review.googlesource.com/c/toolchain/gcc/+/683601)
*
* In such cases, use c10::ThreadLocal<T> wrapper
* which is `pthread_*` based with smart pointer semantics.
*
* In addition, convenient macro C10_DEFINE_TLS_static is available.
* To define static TLS variable of type std::string, do the following
* ```
* C10_DEFINE_TLS_static(std::string, str_tls_);
* ///////
* {
* *str_tls_ = "abc";
* assert(str_tls_->length(), 3);
* }
* ```
*
* (see c10/test/util/ThreadLocal_test.cpp for more examples)
*/
#if !defined(C10_PREFER_CUSTOM_THREAD_LOCAL_STORAGE)
#if defined(C10_ANDROID) && defined(__GLIBCXX__) && __GLIBCXX__ < 20180604
#define C10_PREFER_CUSTOM_THREAD_LOCAL_STORAGE
#endif // defined(C10_ANDROID) && defined(__GLIBCXX__) && __GLIBCXX__ < 20180604
#endif // !defined(C10_PREFER_CUSTOM_THREAD_LOCAL_STORAGE)
#if defined(C10_PREFER_CUSTOM_THREAD_LOCAL_STORAGE)
#include <c10/util/Exception.h>
#include <errno.h>
#include <pthread.h>
#include <memory>
namespace c10 {
/**
* @brief Temporary thread_local C++ qualifier replacement for Android
* based on `pthread_*`.
* To be used with composite types that provide default ctor.
*/
template <typename Type>
class ThreadLocal {
public:
ThreadLocal() {
pthread_key_create(
&key_, [](void* buf) { delete static_cast<Type*>(buf); });
}
~ThreadLocal() {
if (void* current = pthread_getspecific(key_)) {
delete static_cast<Type*>(current);
}
pthread_key_delete(key_);
}
ThreadLocal(const ThreadLocal&) = delete;
ThreadLocal& operator=(const ThreadLocal&) = delete;
Type& get() {
if (void* current = pthread_getspecific(key_)) {
return *static_cast<Type*>(current);
}
std::unique_ptr<Type> ptr = std::make_unique<Type>();
if (0 == pthread_setspecific(key_, ptr.get())) {
return *ptr.release();
}
int err = errno;
TORCH_INTERNAL_ASSERT(false, "pthread_setspecific() failed, errno = ", err);
}
Type& operator*() {
return get();
}
Type* operator->() {
return &get();
}
private:
pthread_key_t key_;
};
} // namespace c10
#define C10_DEFINE_TLS_static(Type, Name) static ::c10::ThreadLocal<Type> Name
#define C10_DECLARE_TLS_class_static(Class, Type, Name) \
static ::c10::ThreadLocal<Type> Name
#define C10_DEFINE_TLS_class_static(Class, Type, Name) \
::c10::ThreadLocal<Type> Class::Name
#else // defined(C10_PREFER_CUSTOM_THREAD_LOCAL_STORAGE)
namespace c10 {
/**
* @brief Default thread_local implementation for non-Android cases.
* To be used with composite types that provide default ctor.
*/
template <typename Type>
class ThreadLocal {
public:
using Accessor = Type* (*)();
explicit ThreadLocal(Accessor accessor) : accessor_(accessor) {}
ThreadLocal(const ThreadLocal&) = delete;
ThreadLocal& operator=(const ThreadLocal&) = delete;
Type& get() {
return *accessor_();
}
Type& operator*() {
return get();
}
Type* operator->() {
return &get();
}
private:
Accessor accessor_;
};
} // namespace c10
#define C10_DEFINE_TLS_static(Type, Name) \
static ::c10::ThreadLocal<Type> Name([]() { \
static thread_local Type var; \
return &var; \
})
#define C10_DECLARE_TLS_class_static(Class, Type, Name) \
static ::c10::ThreadLocal<Type> Name
#define C10_DEFINE_TLS_class_static(Class, Type, Name) \
::c10::ThreadLocal<Type> Class::Name([]() { \
static thread_local Type var; \
return &var; \
})
#endif // defined(C10_PREFER_CUSTOM_THREAD_LOCAL_STORAGE)