[llvm] r255446 - Revert r255444.

Mehdi Amini via llvm-commits llvm-commits at lists.llvm.org
Mon Dec 14 17:08:05 PST 2015


Hi,

Recommitted in r255589, hopefully it will please all the various compilers.
If it breaks again: 

1) Please reply to the commit email you are reverting, so I am aware of what’s going on.
2) If it is on windows: please provide guidance on how to deal with MSVC non-standard compliance.

Thanks,

— 
Mehdi



> On Dec 13, 2015, at 9:22 AM, Mehdi Amini via llvm-commits <llvm-commits at lists.llvm.org> wrote:
> 
> Is it this bug: http://connect.microsoft.com/VisualStudio/feedbackdetail/view/791185/std-packaged-task-t-where-t-is-void-or-a-reference-class-are-not-movable ?
> 
>> Mehdi
> 
>> On Dec 13, 2015, at 9:16 AM, Mehdi Amini via llvm-commits <llvm-commits at lists.llvm.org> wrote:
>> 
>> Hi Nico,
>> 
>> I’ll need help figuring out why MSVC can’t build this, the compile errors are cryptic.
>> 
>> Thanks.
>> 
>>>> Mehdi
>> 
>>> On Dec 12, 2015, at 8:14 PM, Nico Weber via llvm-commits <llvm-commits at lists.llvm.org> wrote:
>>> 
>>> Author: nico
>>> Date: Sat Dec 12 22:14:39 2015
>>> New Revision: 255446
>>> 
>>> URL: http://llvm.org/viewvc/llvm-project?rev=255446&view=rev
>>> Log:
>>> Revert r255444.
>>> 
>>> It doesn't build on Windows and broke the Windows LLD and LLDB bots:
>>> http://lab.llvm.org:8011/builders/lld-x86_64-win7/builds/27693/steps/build_Lld/logs/stdio
>>> http://lab.llvm.org:8011/builders/lldb-x86-windows-msvc/builds/13468/steps/build/logs/stdio
>>> 
>>> Removed:
>>>  llvm/trunk/include/llvm/Support/ThreadPool.h
>>>  llvm/trunk/lib/Support/ThreadPool.cpp
>>>  llvm/trunk/unittests/Support/ThreadPool.cpp
>>> Modified:
>>>  llvm/trunk/include/llvm/Support/thread.h
>>>  llvm/trunk/lib/Support/CMakeLists.txt
>>>  llvm/trunk/unittests/Support/CMakeLists.txt
>>> 
>>> Removed: llvm/trunk/include/llvm/Support/ThreadPool.h
>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Support/ThreadPool.h?rev=255445&view=auto
>>> ==============================================================================
>>> --- llvm/trunk/include/llvm/Support/ThreadPool.h (original)
>>> +++ llvm/trunk/include/llvm/Support/ThreadPool.h (removed)
>>> @@ -1,95 +0,0 @@
>>> -//===-- llvm/Support/ThreadPool.h - A ThreadPool implementation -*- C++ -*-===//
>>> -//
>>> -//                     The LLVM Compiler Infrastructure
>>> -//
>>> -// This file is distributed under the University of Illinois Open Source
>>> -// License. See LICENSE.TXT for details.
>>> -//
>>> -//===----------------------------------------------------------------------===//
>>> -//
>>> -// This file defines a crude C++11 based thread pool.
>>> -//
>>> -//===----------------------------------------------------------------------===//
>>> -
>>> -#ifndef LLVM_SUPPORT_THREAD_POOL_H
>>> -#define LLVM_SUPPORT_THREAD_POOL_H
>>> -
>>> -#include "llvm/Support/thread.h"
>>> -
>>> -#include <condition_variable>
>>> -#include <functional>
>>> -#include <future>
>>> -#include <memory>
>>> -#include <mutex>
>>> -#include <queue>
>>> -#include <utility>
>>> -
>>> -namespace llvm {
>>> -
>>> -/// A ThreadPool for asynchronous parallel execution on a defined number of
>>> -/// threads.
>>> -///
>>> -/// The pool keeps a vector of threads alive, waiting on a condition variable
>>> -/// for some work to become available.
>>> -class ThreadPool {
>>> -public:
>>> -  using TaskTy = std::function<void()>;
>>> -
>>> -  /// Construct a pool with the number of core available on the system (or
>>> -  /// whatever the value returned by std::thread::hardware_concurrency() is).
>>> -  ThreadPool();
>>> -
>>> -  /// Construct a pool of \p ThreadCount threads
>>> -  ThreadPool(unsigned ThreadCount);
>>> -
>>> -  /// Blocking destructor: the pool will wait for all the threads to complete.
>>> -  ~ThreadPool();
>>> -
>>> -  /// Asynchronous submission of a task to the pool. The returned future can be
>>> -  /// used to wait for the task to finish and is *non-blocking* on destruction.
>>> -  template <typename Function, typename... Args>
>>> -  inline std::shared_future<void> async(Function &&F, Args &&... ArgList) {
>>> -    auto Task =
>>> -        std::bind(std::forward<Function>(F), std::forward<Args...>(ArgList...));
>>> -    return asyncImpl(Task);
>>> -  }
>>> -
>>> -  /// Asynchronous submission of a task to the pool. The returned future can be
>>> -  /// used to wait for the task to finish and is *non-blocking* on destruction.
>>> -  template <typename Function>
>>> -  inline std::shared_future<void> async(Function &&F) {
>>> -    return asyncImpl(F);
>>> -  }
>>> -
>>> -  /// Blocking wait for all the threads to complete and the queue to be empty.
>>> -  /// It is an error to try to add new tasks while blocking on this call.
>>> -  void wait();
>>> -
>>> -private:
>>> -  /// Asynchronous submission of a task to the pool. The returned future can be
>>> -  /// used to wait for the task to finish and is *non-blocking* on destruction.
>>> -  std::shared_future<void> asyncImpl(TaskTy f);
>>> -
>>> -  /// Threads in flight
>>> -  std::vector<llvm::thread> Threads;
>>> -
>>> -  /// Tasks waiting for execution in the pool.
>>> -  std::queue<std::packaged_task<void()>> Tasks;
>>> -
>>> -  /// Locking and signaling for accessing the Tasks queue.
>>> -  std::mutex QueueLock;
>>> -  std::condition_variable QueueCondition;
>>> -
>>> -  /// Locking and signaling for job completion
>>> -  std::mutex CompletionLock;
>>> -  std::condition_variable CompletionCondition;
>>> -
>>> -  /// Keep track of the number of thread actually busy
>>> -  std::atomic<unsigned> ActiveThreads;
>>> -
>>> -  /// Signal for the destruction of the pool, asking thread to exit.
>>> -  bool EnableFlag;
>>> -};
>>> -}
>>> -
>>> -#endif // LLVM_SUPPORT_THREAD_POOL_H
>>> 
>>> Modified: llvm/trunk/include/llvm/Support/thread.h
>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Support/thread.h?rev=255446&r1=255445&r2=255446&view=diff
>>> ==============================================================================
>>> --- llvm/trunk/include/llvm/Support/thread.h (original)
>>> +++ llvm/trunk/include/llvm/Support/thread.h Sat Dec 12 22:14:39 2015
>>> @@ -43,8 +43,6 @@ typedef std::thread thread;
>>> 
>>> #else // !LLVM_ENABLE_THREADS
>>> 
>>> -#include <utility>
>>> -
>>> namespace llvm {
>>> 
>>> struct thread {
>>> 
>>> Modified: llvm/trunk/lib/Support/CMakeLists.txt
>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/CMakeLists.txt?rev=255446&r1=255445&r2=255446&view=diff
>>> ==============================================================================
>>> --- llvm/trunk/lib/Support/CMakeLists.txt (original)
>>> +++ llvm/trunk/lib/Support/CMakeLists.txt Sat Dec 12 22:14:39 2015
>>> @@ -89,7 +89,6 @@ add_llvm_library(LLVMSupport
>>> StringRef.cpp
>>> SystemUtils.cpp
>>> TargetParser.cpp
>>> -  ThreadPool.cpp
>>> Timer.cpp
>>> ToolOutputFile.cpp
>>> Triple.cpp
>>> 
>>> Removed: llvm/trunk/lib/Support/ThreadPool.cpp
>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/ThreadPool.cpp?rev=255445&view=auto
>>> ==============================================================================
>>> --- llvm/trunk/lib/Support/ThreadPool.cpp (original)
>>> +++ llvm/trunk/lib/Support/ThreadPool.cpp (removed)
>>> @@ -1,143 +0,0 @@
>>> -//==-- llvm/Support/ThreadPool.cpp - A ThreadPool implementation -*- C++ -*-==//
>>> -//
>>> -//                     The LLVM Compiler Infrastructure
>>> -//
>>> -// This file is distributed under the University of Illinois Open Source
>>> -// License. See LICENSE.TXT for details.
>>> -//
>>> -//===----------------------------------------------------------------------===//
>>> -//
>>> -// This file implements a crude C++11 based thread pool.
>>> -//
>>> -//===----------------------------------------------------------------------===//
>>> -
>>> -#include "llvm/Support/ThreadPool.h"
>>> -
>>> -#include "llvm/Config/llvm-config.h"
>>> -#include "llvm/Support/raw_ostream.h"
>>> -
>>> -using namespace llvm;
>>> -
>>> -#if LLVM_ENABLE_THREADS
>>> -
>>> -// Default to std::thread::hardware_concurrency
>>> -ThreadPool::ThreadPool() : ThreadPool(std::thread::hardware_concurrency()) {}
>>> -
>>> -ThreadPool::ThreadPool(unsigned ThreadCount)
>>> -    : ActiveThreads(0), EnableFlag(true) {
>>> -  // Create ThreadCount threads that will loop forever, wait on QueueCondition
>>> -  // for tasks to be queued or the Pool to be destroyed.
>>> -  Threads.reserve(ThreadCount);
>>> -  for (unsigned ThreadID = 0; ThreadID < ThreadCount; ++ThreadID) {
>>> -    Threads.emplace_back([&] {
>>> -      while (true) {
>>> -        std::packaged_task<void()> Task;
>>> -        {
>>> -          std::unique_lock<std::mutex> LockGuard(QueueLock);
>>> -          // Wait for tasks to be pushed in the queue
>>> -          QueueCondition.wait(LockGuard,
>>> -                              [&] { return !EnableFlag || !Tasks.empty(); });
>>> -          // Exit condition
>>> -          if (!EnableFlag && Tasks.empty())
>>> -            return;
>>> -          // Yeah, we have a task, grab it and release the lock on the queue
>>> -
>>> -          // We first need to signal that we are active before popping the queue
>>> -          // in order for wait() to properly detect that even if the queue is
>>> -          // empty, there is still a task in flight.
>>> -          {
>>> -            ++ActiveThreads;
>>> -            std::unique_lock<std::mutex> LockGuard(CompletionLock);
>>> -          }
>>> -          Task = std::move(Tasks.front());
>>> -          Tasks.pop();
>>> -        }
>>> -        // Run the task we just grabbed
>>> -        Task();
>>> -
>>> -        {
>>> -          // Adjust `ActiveThreads`, in case someone waits on ThreadPool::wait()
>>> -          std::unique_lock<std::mutex> LockGuard(CompletionLock);
>>> -          --ActiveThreads;
>>> -        }
>>> -
>>> -        // Notify task completion, in case someone waits on ThreadPool::wait()
>>> -        CompletionCondition.notify_all();
>>> -      }
>>> -    });
>>> -  }
>>> -}
>>> -
>>> -void ThreadPool::wait() {
>>> -  // Wait for all threads to complete and the queue to be empty
>>> -  std::unique_lock<std::mutex> LockGuard(CompletionLock);
>>> -  CompletionCondition.wait(LockGuard,
>>> -                           [&] { return Tasks.empty() && !ActiveThreads; });
>>> -}
>>> -
>>> -std::shared_future<void> ThreadPool::asyncImpl(TaskTy Task) {
>>> -  /// Wrap the Task in a packaged_task to return a future object.
>>> -  std::packaged_task<void()> PackagedTask(std::move(Task));
>>> -  std::future<void> Future = PackagedTask.get_future();
>>> -  {
>>> -    // Lock the queue and push the new task
>>> -    std::unique_lock<std::mutex> LockGuard(QueueLock);
>>> -
>>> -    // Don't allow enqueueing after disabling the pool
>>> -    assert(EnableFlag && "Queuing a thread during ThreadPool destruction");
>>> -
>>> -    Tasks.push(std::move(PackagedTask));
>>> -  }
>>> -  QueueCondition.notify_one();
>>> -  return Future.share();
>>> -}
>>> -
>>> -// The destructor joins all threads, waiting for completion.
>>> -ThreadPool::~ThreadPool() {
>>> -  {
>>> -    std::unique_lock<std::mutex> LockGuard(QueueLock);
>>> -    EnableFlag = false;
>>> -  }
>>> -  QueueCondition.notify_all();
>>> -  for (auto &Worker : Threads)
>>> -    Worker.join();
>>> -}
>>> -
>>> -#else // LLVM_ENABLE_THREADS Disabled
>>> -
>>> -ThreadPool::ThreadPool() : ThreadPool(0) {}
>>> -
>>> -// No threads are launched, issue a warning if ThreadCount is not 0
>>> -ThreadPool::ThreadPool(unsigned ThreadCount)
>>> -    : ActiveThreads(0), EnableFlag(true) {
>>> -  if (ThreadCount) {
>>> -    errs() << "Warning: request a ThreadPool with " << ThreadCount
>>> -           << " threads, but LLVM_ENABLE_THREADS has been turned off\n";
>>> -  }
>>> -}
>>> -
>>> -void ThreadPool::wait() {
>>> -  // Sequential implementation running the tasks
>>> -  while (!Tasks.empty()) {
>>> -    auto Task = std::move(Tasks.front());
>>> -    Tasks.pop();
>>> -    Task();
>>> -  }
>>> -}
>>> -
>>> -std::shared_future<void> ThreadPool::asyncImpl(TaskTy Task) {
>>> -  // Get a Future with launch::deferred execution using std::async
>>> -  auto Future = std::async(std::launch::deferred, std::move(Task)).share();
>>> -  // Wrap the future so that both ThreadPool::wait() can operate and the
>>> -  // returned future can be sync'ed on.
>>> -  std::packaged_task<void()> PackagedTask([Future]() { Future.get(); });
>>> -  Tasks.push(std::move(PackagedTask));
>>> -  return Future;
>>> -}
>>> -
>>> -ThreadPool::~ThreadPool() {
>>> -  EnableFlag = false;
>>> -  wait();
>>> -}
>>> -
>>> -#endif
>>> 
>>> Modified: llvm/trunk/unittests/Support/CMakeLists.txt
>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/unittests/Support/CMakeLists.txt?rev=255446&r1=255445&r2=255446&view=diff
>>> ==============================================================================
>>> --- llvm/trunk/unittests/Support/CMakeLists.txt (original)
>>> +++ llvm/trunk/unittests/Support/CMakeLists.txt Sat Dec 12 22:14:39 2015
>>> @@ -41,7 +41,6 @@ add_llvm_unittest(SupportTests
>>> SwapByteOrderTest.cpp
>>> TargetRegistry.cpp
>>> ThreadLocalTest.cpp
>>> -  ThreadPool.cpp
>>> TimeValueTest.cpp
>>> TrailingObjectsTest.cpp
>>> UnicodeTest.cpp
>>> 
>>> Removed: llvm/trunk/unittests/Support/ThreadPool.cpp
>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/unittests/Support/ThreadPool.cpp?rev=255445&view=auto
>>> ==============================================================================
>>> --- llvm/trunk/unittests/Support/ThreadPool.cpp (original)
>>> +++ llvm/trunk/unittests/Support/ThreadPool.cpp (removed)
>>> @@ -1,91 +0,0 @@
>>> -//========- unittests/Support/ThreadPools.cpp - ThreadPools.h tests --========//
>>> -//
>>> -//                     The LLVM Compiler Infrastructure
>>> -//
>>> -// This file is distributed under the University of Illinois Open Source
>>> -// License. See LICENSE.TXT for details.
>>> -//
>>> -//===----------------------------------------------------------------------===//
>>> -
>>> -#include "llvm/Support/ThreadPool.h"
>>> -
>>> -#include "llvm/ADT/STLExtras.h"
>>> -
>>> -#include "gtest/gtest.h"
>>> -
>>> -using namespace llvm;
>>> -using namespace std::chrono;
>>> -
>>> -/// Try best to make this thread not progress faster than the main thread
>>> -static void yield() {
>>> -#ifdef LLVM_ENABLE_THREADS
>>> -  std::this_thread::yield();
>>> -#endif
>>> -  std::this_thread::sleep_for(milliseconds(200));
>>> -#ifdef LLVM_ENABLE_THREADS
>>> -  std::this_thread::yield();
>>> -#endif
>>> -}
>>> -
>>> -TEST(ThreadPoolTest, AsyncBarrier) {
>>> -  // test that async & barrier work together properly.
>>> -
>>> -  std::atomic_int checked_in{0};
>>> -
>>> -  ThreadPool Pool;
>>> -  for (size_t i = 0; i < 5; ++i) {
>>> -    Pool.async([&checked_in, i] {
>>> -      yield();
>>> -      ++checked_in;
>>> -    });
>>> -  }
>>> -  ASSERT_EQ(0, checked_in);
>>> -  Pool.wait();
>>> -  ASSERT_EQ(5, checked_in);
>>> -}
>>> -
>>> -TEST(ThreadPoolTest, Async) {
>>> -  ThreadPool Pool;
>>> -  std::atomic_int i{0};
>>> -  // sleep here just to ensure that the not-equal is correct.
>>> -  Pool.async([&i] {
>>> -    yield();
>>> -    ++i;
>>> -  });
>>> -  Pool.async([&i] { ++i; });
>>> -  ASSERT_NE(2, i.load());
>>> -  Pool.wait();
>>> -  ASSERT_EQ(2, i.load());
>>> -}
>>> -
>>> -TEST(ThreadPoolTest, GetFuture) {
>>> -  ThreadPool Pool;
>>> -  std::atomic_int i{0};
>>> -  // sleep here just to ensure that the not-equal is correct.
>>> -  Pool.async([&i] {
>>> -    yield();
>>> -    ++i;
>>> -  });
>>> -  // Force the future using get()
>>> -  Pool.async([&i] { ++i; }).get();
>>> -  ASSERT_NE(2, i.load());
>>> -  Pool.wait();
>>> -  ASSERT_EQ(2, i.load());
>>> -}
>>> -
>>> -TEST(ThreadPoolTest, PoolDestruction) {
>>> -  // Test that we are waiting on destruction
>>> -  std::atomic_int checked_in{0};
>>> -
>>> -  {
>>> -    ThreadPool Pool;
>>> -    for (size_t i = 0; i < 5; ++i) {
>>> -      Pool.async([&checked_in, i] {
>>> -        yield();
>>> -        ++checked_in;
>>> -      });
>>> -    }
>>> -    ASSERT_EQ(0, checked_in);
>>> -  }
>>> -  ASSERT_EQ(5, checked_in);
>>> -}
>>> 
>>> 
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