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//===-- llvm/Support/thread.h - Wrapper for <thread> ------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This header is a wrapper for <thread> that works around problems with the
// MSVC headers when exceptions are disabled. It also provides llvm::thread,
// which is either a typedef of std::thread or a replacement that calls the
// function synchronously depending on the value of LLVM_ENABLE_THREADS.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_SUPPORT_THREAD_H
#define LLVM_SUPPORT_THREAD_H
#include "llvm/Config/llvm-config.h"
#include <optional>
#ifdef _WIN32
typedef unsigned long DWORD;
typedef void *PVOID;
typedef PVOID HANDLE;
#endif
#if LLVM_ENABLE_THREADS
#include <thread>
namespace llvm {
#if LLVM_ON_UNIX || _WIN32
/// LLVM thread following std::thread interface with added constructor to
/// specify stack size.
class thread {
template <typename CalleeTuple> static void GenericThreadProxy(void *Ptr) {
std::unique_ptr<CalleeTuple> Callee(static_cast<CalleeTuple *>(Ptr));
std::apply(
[](auto &&F, auto &&...Args) {
std::forward<decltype(F)>(F)(std::forward<decltype(Args)>(Args)...);
},
*Callee);
}
public:
#if LLVM_ON_UNIX
using native_handle_type = pthread_t;
using id = pthread_t;
using start_routine_type = void *(*)(void *);
template <typename CalleeTuple> static void *ThreadProxy(void *Ptr) {
GenericThreadProxy<CalleeTuple>(Ptr);
return nullptr;
}
#elif _WIN32
using native_handle_type = HANDLE;
using id = DWORD;
using start_routine_type = unsigned(__stdcall *)(void *);
template <typename CalleeTuple>
static unsigned __stdcall ThreadProxy(void *Ptr) {
GenericThreadProxy<CalleeTuple>(Ptr);
return 0;
}
#endif
static const std::optional<unsigned> DefaultStackSize;
thread() : Thread(native_handle_type()) {}
thread(thread &&Other) noexcept
: Thread(std::exchange(Other.Thread, native_handle_type())) {}
template <class Function, class... Args>
explicit thread(Function &&f, Args &&...args)
: thread(DefaultStackSize, f, args...) {}
template <class Function, class... Args>
explicit thread(std::optional<unsigned> StackSizeInBytes, Function &&f,
Args &&...args);
thread(const thread &) = delete;
~thread() {
if (joinable())
std::terminate();
}
thread &operator=(thread &&Other) noexcept {
if (joinable())
std::terminate();
Thread = std::exchange(Other.Thread, native_handle_type());
return *this;
}
bool joinable() const noexcept { return Thread != native_handle_type(); }
inline id get_id() const noexcept;
native_handle_type native_handle() const noexcept { return Thread; }
static unsigned hardware_concurrency() {
return std::thread::hardware_concurrency();
};
inline void join();
inline void detach();
void swap(llvm::thread &Other) noexcept { std::swap(Thread, Other.Thread); }
private:
native_handle_type Thread;
};
thread::native_handle_type
llvm_execute_on_thread_impl(thread::start_routine_type ThreadFunc, void *Arg,
std::optional<unsigned> StackSizeInBytes);
void llvm_thread_join_impl(thread::native_handle_type Thread);
void llvm_thread_detach_impl(thread::native_handle_type Thread);
thread::id llvm_thread_get_id_impl(thread::native_handle_type Thread);
thread::id llvm_thread_get_current_id_impl();
template <class Function, class... Args>
thread::thread(std::optional<unsigned> StackSizeInBytes, Function &&f,
Args &&...args) {
typedef std::tuple<std::decay_t<Function>, std::decay_t<Args>...> CalleeTuple;
std::unique_ptr<CalleeTuple> Callee(
new CalleeTuple(std::forward<Function>(f), std::forward<Args>(args)...));
Thread = llvm_execute_on_thread_impl(ThreadProxy<CalleeTuple>, Callee.get(),
StackSizeInBytes);
if (Thread != native_handle_type())
Callee.release();
}
thread::id thread::get_id() const noexcept {
return llvm_thread_get_id_impl(Thread);
}
void thread::join() {
llvm_thread_join_impl(Thread);
Thread = native_handle_type();
}
void thread::detach() {
llvm_thread_detach_impl(Thread);
Thread = native_handle_type();
}
namespace this_thread {
inline thread::id get_id() { return llvm_thread_get_current_id_impl(); }
} // namespace this_thread
#else // !LLVM_ON_UNIX && !_WIN32
/// std::thread backed implementation of llvm::thread interface that ignores the
/// stack size request.
class thread {
public:
using native_handle_type = std::thread::native_handle_type;
using id = std::thread::id;
thread() : Thread(std::thread()) {}
thread(thread &&Other) noexcept
: Thread(std::exchange(Other.Thread, std::thread())) {}
template <class Function, class... Args>
explicit thread(std::optional<unsigned> StackSizeInBytes, Function &&f,
Args &&...args)
: Thread(std::forward<Function>(f), std::forward<Args>(args)...) {}
template <class Function, class... Args>
explicit thread(Function &&f, Args &&...args) : Thread(f, args...) {}
thread(const thread &) = delete;
~thread() {}
thread &operator=(thread &&Other) noexcept {
Thread = std::exchange(Other.Thread, std::thread());
return *this;
}
bool joinable() const noexcept { return Thread.joinable(); }
id get_id() const noexcept { return Thread.get_id(); }
native_handle_type native_handle() noexcept { return Thread.native_handle(); }
static unsigned hardware_concurrency() {
return std::thread::hardware_concurrency();
};
inline void join() { Thread.join(); }
inline void detach() { Thread.detach(); }
void swap(llvm::thread &Other) noexcept { std::swap(Thread, Other.Thread); }
private:
std::thread Thread;
};
namespace this_thread {
inline thread::id get_id() { return std::this_thread::get_id(); }
}
#endif // LLVM_ON_UNIX || _WIN32
} // namespace llvm
#else // !LLVM_ENABLE_THREADS
#include <utility>
namespace llvm {
struct thread {
thread() {}
thread(thread &&other) {}
template <class Function, class... Args>
explicit thread(std::optional<unsigned> StackSizeInBytes, Function &&f,
Args &&...args) {
f(std::forward<Args>(args)...);
}
template <class Function, class... Args>
explicit thread(Function &&f, Args &&...args) {
f(std::forward<Args>(args)...);
}
thread(const thread &) = delete;
void detach() {
report_fatal_error("Detaching from a thread does not make sense with no "
"threading support");
}
void join() {}
static unsigned hardware_concurrency() { return 1; };
};
} // namespace llvm
#endif // LLVM_ENABLE_THREADS
#endif // LLVM_SUPPORT_THREAD_H
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