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//==--- Linux.cpp - Threading abstraction implementation ------- -*-C++ -*-===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2022 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
//
//===----------------------------------------------------------------------===//
//
// Implements threading support for Linux
//
//===----------------------------------------------------------------------===//
#if SWIFT_THREADING_LINUX
#include "swift/Threading/Impl.h"
#include "swift/Threading/Errors.h"
#include "swift/Threading/ThreadSanitizer.h"
namespace {
#pragma clang diagnostic push
#pragma GCC diagnostic ignored "-Wglobal-constructors"
class MainThreadRememberer {
private:
pthread_t mainThread_;
public:
MainThreadRememberer() { mainThread_ = pthread_self(); }
pthread_t main_thread() const { return mainThread_; }
};
MainThreadRememberer rememberer;
#if !defined(__LP64__) && !defined(_LP64)
pthread_mutex_t once_mutex = PTHREAD_MUTEX_INITIALIZER;
#endif
#pragma clang diagnostic pop
} // namespace
using namespace swift;
using namespace threading_impl;
bool swift::threading_impl::thread_is_main() {
return pthread_equal(pthread_self(), rememberer.main_thread());
}
void swift::threading_impl::once_slow(once_t &predicate, void (*fn)(void *),
void *context) {
// On 32-bit Linux we can't have per-once locks
#if defined(__LP64__) || defined(_LP64)
linux::ulock_lock(&predicate.lock);
#else
pthread_mutex_lock(&once_mutex);
#endif
if (predicate.flag.load(std::memory_order_acquire) == 0) {
fn(context);
predicate.flag.store(tsan::enabled() ? 1 : -1, std::memory_order_release);
}
#if defined(__LP64__) || defined(_LP64)
linux::ulock_unlock(&predicate.lock);
#else
pthread_mutex_unlock(&once_mutex);
#endif
}
std::optional<swift::threading_impl::stack_bounds>
swift::threading_impl::thread_get_current_stack_bounds() {
pthread_attr_t attr;
size_t size = 0;
void *begin = nullptr;
if (!pthread_getattr_np(pthread_self(), &attr)) {
if (!pthread_attr_getstack(&attr, &begin, &size)) {
stack_bounds result = { begin, (char *)begin + size };
pthread_attr_destroy(&attr);
return result;
}
pthread_attr_destroy(&attr);
}
return {};
}
#endif // SWIFT_THREADING_LINUX
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