forked from OSchip/llvm-project
120 lines
3.1 KiB
C++
120 lines
3.1 KiB
C++
#include "Threading.h"
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#include "Trace.h"
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#include "llvm/ADT/ScopeExit.h"
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#include "llvm/Support/FormatVariadic.h"
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#include "llvm/Support/Threading.h"
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#include <atomic>
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#include <thread>
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#ifdef __USE_POSIX
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#include <pthread.h>
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#elif defined(__APPLE__)
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#include <sys/resource.h>
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#elif defined (_WIN32)
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#include <windows.h>
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#endif
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namespace clang {
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namespace clangd {
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void Notification::notify() {
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{
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std::lock_guard<std::mutex> Lock(Mu);
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Notified = true;
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// Broadcast with the lock held. This ensures that it's safe to destroy
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// a Notification after wait() returns, even from another thread.
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CV.notify_all();
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}
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}
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void Notification::wait() const {
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std::unique_lock<std::mutex> Lock(Mu);
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CV.wait(Lock, [this] { return Notified; });
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}
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Semaphore::Semaphore(std::size_t MaxLocks) : FreeSlots(MaxLocks) {}
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bool Semaphore::try_lock() {
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std::unique_lock<std::mutex> Lock(Mutex);
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if (FreeSlots > 0) {
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--FreeSlots;
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return true;
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}
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return false;
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}
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void Semaphore::lock() {
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trace::Span Span("WaitForFreeSemaphoreSlot");
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// trace::Span can also acquire locks in ctor and dtor, we make sure it
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// happens when Semaphore's own lock is not held.
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{
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std::unique_lock<std::mutex> Lock(Mutex);
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SlotsChanged.wait(Lock, [&]() { return FreeSlots > 0; });
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--FreeSlots;
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}
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}
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void Semaphore::unlock() {
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std::unique_lock<std::mutex> Lock(Mutex);
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++FreeSlots;
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Lock.unlock();
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SlotsChanged.notify_one();
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}
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AsyncTaskRunner::~AsyncTaskRunner() { wait(); }
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bool AsyncTaskRunner::wait(Deadline D) const {
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std::unique_lock<std::mutex> Lock(Mutex);
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return clangd::wait(Lock, TasksReachedZero, D,
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[&] { return InFlightTasks == 0; });
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}
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void AsyncTaskRunner::runAsync(const llvm::Twine &Name,
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llvm::unique_function<void()> Action) {
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{
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std::lock_guard<std::mutex> Lock(Mutex);
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++InFlightTasks;
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}
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auto CleanupTask = llvm::make_scope_exit([this]() {
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std::lock_guard<std::mutex> Lock(Mutex);
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int NewTasksCnt = --InFlightTasks;
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if (NewTasksCnt == 0) {
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// Note: we can't unlock here because we don't want the object to be
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// destroyed before we notify.
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TasksReachedZero.notify_one();
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}
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});
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std::thread(
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[](std::string Name, decltype(Action) Action, decltype(CleanupTask)) {
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llvm::set_thread_name(Name);
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Action();
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// Make sure function stored by Action is destroyed before CleanupTask
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// is run.
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Action = nullptr;
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},
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Name.str(), std::move(Action), std::move(CleanupTask))
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.detach();
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}
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Deadline timeoutSeconds(llvm::Optional<double> Seconds) {
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using namespace std::chrono;
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if (!Seconds)
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return Deadline::infinity();
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return steady_clock::now() +
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duration_cast<steady_clock::duration>(duration<double>(*Seconds));
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}
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void wait(std::unique_lock<std::mutex> &Lock, std::condition_variable &CV,
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Deadline D) {
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if (D == Deadline::zero())
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return;
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if (D == Deadline::infinity())
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return CV.wait(Lock);
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CV.wait_until(Lock, D.time());
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}
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} // namespace clangd
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} // namespace clang
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