diff options
Diffstat (limited to 'include/lld/Core/Parallel.h')
| -rw-r--r-- | include/lld/Core/Parallel.h | 279 |
1 files changed, 55 insertions, 224 deletions
diff --git a/include/lld/Core/Parallel.h b/include/lld/Core/Parallel.h index 64b4f2ab04d8d..58fa87e85c51c 100644 --- a/include/lld/Core/Parallel.h +++ b/include/lld/Core/Parallel.h @@ -10,16 +10,12 @@ #ifndef LLD_CORE_PARALLEL_H #define LLD_CORE_PARALLEL_H -#include "lld/Core/Instrumentation.h" #include "lld/Core/LLVM.h" +#include "lld/Core/TaskGroup.h" #include "llvm/Support/MathExtras.h" -#include "llvm/Support/thread.h" +#include "llvm/Config/llvm-config.h" #include <algorithm> -#include <atomic> -#include <condition_variable> -#include <mutex> -#include <stack> #if defined(_MSC_VER) && LLVM_ENABLE_THREADS #include <concrt.h> @@ -27,249 +23,84 @@ #endif namespace lld { -/// \brief Allows one or more threads to wait on a potentially unknown number of -/// events. -/// -/// A latch starts at \p count. inc() increments this, and dec() decrements it. -/// All calls to sync() will block while the count is not 0. -/// -/// Calling dec() on a Latch with a count of 0 has undefined behaivor. -class Latch { - uint32_t _count; - mutable std::mutex _condMut; - mutable std::condition_variable _cond; -public: - explicit Latch(uint32_t count = 0) : _count(count) {} - ~Latch() { sync(); } - - void inc() { - std::unique_lock<std::mutex> lock(_condMut); - ++_count; - } - - void dec() { - std::unique_lock<std::mutex> lock(_condMut); - if (--_count == 0) - _cond.notify_all(); - } - - void sync() const { - std::unique_lock<std::mutex> lock(_condMut); - _cond.wait(lock, [&] { - return _count == 0; - }); - } -}; - -// Classes in this namespace are implementation details of this header. -namespace internal { - -/// \brief An abstract class that takes closures and runs them asynchronously. -class Executor { -public: - virtual ~Executor() = default; - virtual void add(std::function<void()> func) = 0; -}; - -#if !defined(LLVM_ENABLE_THREADS) || LLVM_ENABLE_THREADS == 0 -class SyncExecutor : public Executor { -public: - virtual void add(std::function<void()> func) { - func(); - } -}; - -inline Executor *getDefaultExecutor() { - static SyncExecutor exec; - return &exec; -} -#elif defined(_MSC_VER) -/// \brief An Executor that runs tasks via ConcRT. -class ConcRTExecutor : public Executor { - struct Taskish { - Taskish(std::function<void()> task) : _task(task) {} - - std::function<void()> _task; - - static void run(void *p) { - Taskish *self = static_cast<Taskish *>(p); - self->_task(); - concurrency::Free(self); - } - }; - -public: - virtual void add(std::function<void()> func) { - Concurrency::CurrentScheduler::ScheduleTask(Taskish::run, - new (concurrency::Alloc(sizeof(Taskish))) Taskish(func)); - } -}; - -inline Executor *getDefaultExecutor() { - static ConcRTExecutor exec; - return &exec; -} -#else -/// \brief An implementation of an Executor that runs closures on a thread pool -/// in filo order. -class ThreadPoolExecutor : public Executor { -public: - explicit ThreadPoolExecutor(unsigned threadCount = - std::thread::hardware_concurrency()) - : _stop(false), _done(threadCount) { - // Spawn all but one of the threads in another thread as spawning threads - // can take a while. - std::thread([&, threadCount] { - for (size_t i = 1; i < threadCount; ++i) { - std::thread([=] { - work(); - }).detach(); - } - work(); - }).detach(); - } - - ~ThreadPoolExecutor() override { - std::unique_lock<std::mutex> lock(_mutex); - _stop = true; - lock.unlock(); - _cond.notify_all(); - // Wait for ~Latch. - } - - void add(std::function<void()> f) override { - std::unique_lock<std::mutex> lock(_mutex); - _workStack.push(f); - lock.unlock(); - _cond.notify_one(); - } - -private: - void work() { - while (true) { - std::unique_lock<std::mutex> lock(_mutex); - _cond.wait(lock, [&] { - return _stop || !_workStack.empty(); - }); - if (_stop) - break; - auto task = _workStack.top(); - _workStack.pop(); - lock.unlock(); - task(); - } - _done.dec(); - } - - std::atomic<bool> _stop; - std::stack<std::function<void()>> _workStack; - std::mutex _mutex; - std::condition_variable _cond; - Latch _done; -}; - -inline Executor *getDefaultExecutor() { - static ThreadPoolExecutor exec; - return &exec; -} -#endif - -} // namespace internal - -/// \brief Allows launching a number of tasks and waiting for them to finish -/// either explicitly via sync() or implicitly on destruction. -class TaskGroup { - Latch _latch; - -public: - void spawn(std::function<void()> f) { - _latch.inc(); - internal::getDefaultExecutor()->add([&, f] { - f(); - _latch.dec(); - }); - } - - void sync() const { _latch.sync(); } -}; - -#if !defined(LLVM_ENABLE_THREADS) || LLVM_ENABLE_THREADS == 0 -template <class RandomAccessIterator, class Comp> +#if !LLVM_ENABLE_THREADS +template <class RandomAccessIterator, class Comparator> void parallel_sort( - RandomAccessIterator start, RandomAccessIterator end, - const Comp &comp = std::less< + RandomAccessIterator Start, RandomAccessIterator End, + const Comparator &Comp = std::less< typename std::iterator_traits<RandomAccessIterator>::value_type>()) { - std::sort(start, end, comp); + std::sort(Start, End, Comp); } #elif defined(_MSC_VER) // Use ppl parallel_sort on Windows. -template <class RandomAccessIterator, class Comp> +template <class RandomAccessIterator, class Comparator> void parallel_sort( - RandomAccessIterator start, RandomAccessIterator end, - const Comp &comp = std::less< + RandomAccessIterator Start, RandomAccessIterator End, + const Comparator &Comp = std::less< typename std::iterator_traits<RandomAccessIterator>::value_type>()) { - concurrency::parallel_sort(start, end, comp); + concurrency::parallel_sort(Start, End, Comp); } #else namespace detail { -const ptrdiff_t minParallelSize = 1024; +const ptrdiff_t MinParallelSize = 1024; /// \brief Inclusive median. -template <class RandomAccessIterator, class Comp> -RandomAccessIterator medianOf3(RandomAccessIterator start, - RandomAccessIterator end, const Comp &comp) { - RandomAccessIterator mid = start + (std::distance(start, end) / 2); - return comp(*start, *(end - 1)) - ? (comp(*mid, *(end - 1)) ? (comp(*start, *mid) ? mid : start) - : end - 1) - : (comp(*mid, *start) ? (comp(*(end - 1), *mid) ? mid : end - 1) - : start); -} - -template <class RandomAccessIterator, class Comp> -void parallel_quick_sort(RandomAccessIterator start, RandomAccessIterator end, - const Comp &comp, TaskGroup &tg, size_t depth) { +template <class RandomAccessIterator, class Comparator> +RandomAccessIterator medianOf3(RandomAccessIterator Start, + RandomAccessIterator End, + const Comparator &Comp) { + RandomAccessIterator Mid = Start + (std::distance(Start, End) / 2); + return Comp(*Start, *(End - 1)) + ? (Comp(*Mid, *(End - 1)) ? (Comp(*Start, *Mid) ? Mid : Start) + : End - 1) + : (Comp(*Mid, *Start) ? (Comp(*(End - 1), *Mid) ? Mid : End - 1) + : Start); +} + +template <class RandomAccessIterator, class Comparator> +void parallel_quick_sort(RandomAccessIterator Start, RandomAccessIterator End, + const Comparator &Comp, TaskGroup &TG, size_t Depth) { // Do a sequential sort for small inputs. - if (std::distance(start, end) < detail::minParallelSize || depth == 0) { - std::sort(start, end, comp); + if (std::distance(Start, End) < detail::MinParallelSize || Depth == 0) { + std::sort(Start, End, Comp); return; } // Partition. - auto pivot = medianOf3(start, end, comp); - // Move pivot to end. - std::swap(*(end - 1), *pivot); - pivot = std::partition(start, end - 1, [&comp, end](decltype(*start) v) { - return comp(v, *(end - 1)); + auto Pivot = medianOf3(Start, End, Comp); + // Move Pivot to End. + std::swap(*(End - 1), *Pivot); + Pivot = std::partition(Start, End - 1, [&Comp, End](decltype(*Start) V) { + return Comp(V, *(End - 1)); }); - // Move pivot to middle of partition. - std::swap(*pivot, *(end - 1)); + // Move Pivot to middle of partition. + std::swap(*Pivot, *(End - 1)); // Recurse. - tg.spawn([=, &comp, &tg] { - parallel_quick_sort(start, pivot, comp, tg, depth - 1); + TG.spawn([=, &Comp, &TG] { + parallel_quick_sort(Start, Pivot, Comp, TG, Depth - 1); }); - parallel_quick_sort(pivot + 1, end, comp, tg, depth - 1); + parallel_quick_sort(Pivot + 1, End, Comp, TG, Depth - 1); } } -template <class RandomAccessIterator, class Comp> +template <class RandomAccessIterator, class Comparator> void parallel_sort( - RandomAccessIterator start, RandomAccessIterator end, - const Comp &comp = std::less< + RandomAccessIterator Start, RandomAccessIterator End, + const Comparator &Comp = std::less< typename std::iterator_traits<RandomAccessIterator>::value_type>()) { - TaskGroup tg; - detail::parallel_quick_sort(start, end, comp, tg, - llvm::Log2_64(std::distance(start, end)) + 1); + TaskGroup TG; + detail::parallel_quick_sort(Start, End, Comp, TG, + llvm::Log2_64(std::distance(Start, End)) + 1); } #endif -template <class T> void parallel_sort(T *start, T *end) { - parallel_sort(start, end, std::less<T>()); +template <class T> void parallel_sort(T *Start, T *End) { + parallel_sort(Start, End, std::less<T>()); } -#if !defined(LLVM_ENABLE_THREADS) || LLVM_ENABLE_THREADS == 0 +#if !LLVM_ENABLE_THREADS template <class IterTy, class FuncTy> void parallel_for_each(IterTy Begin, IterTy End, FuncTy Fn) { std::for_each(Begin, End, Fn); @@ -302,12 +133,12 @@ void parallel_for_each(IterTy Begin, IterTy End, FuncTy Fn) { if (TaskSize == 0) TaskSize = 1; - TaskGroup Tg; + TaskGroup TG; while (TaskSize <= std::distance(Begin, End)) { - Tg.spawn([=, &Fn] { std::for_each(Begin, Begin + TaskSize, Fn); }); + TG.spawn([=, &Fn] { std::for_each(Begin, Begin + TaskSize, Fn); }); Begin += TaskSize; } - Tg.spawn([=, &Fn] { std::for_each(Begin, End, Fn); }); + TG.spawn([=, &Fn] { std::for_each(Begin, End, Fn); }); } template <class IndexTy, class FuncTy> @@ -316,20 +147,20 @@ void parallel_for(IndexTy Begin, IndexTy End, FuncTy Fn) { if (TaskSize == 0) TaskSize = 1; - TaskGroup Tg; + TaskGroup TG; IndexTy I = Begin; for (; I + TaskSize < End; I += TaskSize) { - Tg.spawn([=, &Fn] { + TG.spawn([=, &Fn] { for (IndexTy J = I, E = I + TaskSize; J != E; ++J) Fn(J); }); } - Tg.spawn([=, &Fn] { + TG.spawn([=, &Fn] { for (IndexTy J = I; J < End; ++J) Fn(J); }); } #endif -} // end namespace lld +} // End namespace lld #endif // LLD_CORE_PARALLEL_H |