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authorrobot-ydb-importer <[email protected]>2024-02-01 17:04:24 +0300
committerAlexander Smirnov <[email protected]>2024-02-09 19:16:57 +0300
commit92eec2d2cadb061e8d0736fc1e6006255d1db6aa (patch)
tree374efcbf55311667e4f87ee2790bf71ac6756ae4 /contrib/libs/llvm12/include/llvm/Support/Parallel.h
parentb34656eaa432fe5258085ca4e4642774fe082456 (diff)
YDB Import 559
Diffstat (limited to 'contrib/libs/llvm12/include/llvm/Support/Parallel.h')
-rw-r--r--contrib/libs/llvm12/include/llvm/Support/Parallel.h318
1 files changed, 0 insertions, 318 deletions
diff --git a/contrib/libs/llvm12/include/llvm/Support/Parallel.h b/contrib/libs/llvm12/include/llvm/Support/Parallel.h
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--- a/contrib/libs/llvm12/include/llvm/Support/Parallel.h
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@@ -1,318 +0,0 @@
-#pragma once
-
-#ifdef __GNUC__
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Wunused-parameter"
-#endif
-
-//===- llvm/Support/Parallel.h - Parallel algorithms ----------------------===//
-//
-// 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
-//
-//===----------------------------------------------------------------------===//
-
-#ifndef LLVM_SUPPORT_PARALLEL_H
-#define LLVM_SUPPORT_PARALLEL_H
-
-#include "llvm/ADT/STLExtras.h"
-#include "llvm/Config/llvm-config.h"
-#include "llvm/Support/Error.h"
-#include "llvm/Support/MathExtras.h"
-#include "llvm/Support/Threading.h"
-
-#include <algorithm>
-#include <condition_variable>
-#include <functional>
-#include <mutex>
-
-namespace llvm {
-
-namespace parallel {
-
-// Strategy for the default executor used by the parallel routines provided by
-// this file. It defaults to using all hardware threads and should be
-// initialized before the first use of parallel routines.
-extern ThreadPoolStrategy strategy;
-
-namespace detail {
-
-#if LLVM_ENABLE_THREADS
-
-class Latch {
- uint32_t Count;
- mutable std::mutex Mutex;
- mutable std::condition_variable Cond;
-
-public:
- explicit Latch(uint32_t Count = 0) : Count(Count) {}
- ~Latch() { sync(); }
-
- void inc() {
- std::lock_guard<std::mutex> lock(Mutex);
- ++Count;
- }
-
- void dec() {
- std::lock_guard<std::mutex> lock(Mutex);
- if (--Count == 0)
- Cond.notify_all();
- }
-
- void sync() const {
- std::unique_lock<std::mutex> lock(Mutex);
- Cond.wait(lock, [&] { return Count == 0; });
- }
-};
-
-class TaskGroup {
- Latch L;
- bool Parallel;
-
-public:
- TaskGroup();
- ~TaskGroup();
-
- void spawn(std::function<void()> f);
-
- void sync() const { L.sync(); }
-};
-
-const ptrdiff_t MinParallelSize = 1024;
-
-/// Inclusive median.
-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) {
- llvm::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));
- });
- // 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);
- });
- parallel_quick_sort(Pivot + 1, End, Comp, TG, Depth - 1);
-}
-
-template <class RandomAccessIterator, class Comparator>
-void parallel_sort(RandomAccessIterator Start, RandomAccessIterator End,
- const Comparator &Comp) {
- TaskGroup TG;
- parallel_quick_sort(Start, End, Comp, TG,
- llvm::Log2_64(std::distance(Start, End)) + 1);
-}
-
-// TaskGroup has a relatively high overhead, so we want to reduce
-// the number of spawn() calls. We'll create up to 1024 tasks here.
-// (Note that 1024 is an arbitrary number. This code probably needs
-// improving to take the number of available cores into account.)
-enum { MaxTasksPerGroup = 1024 };
-
-template <class IterTy, class FuncTy>
-void parallel_for_each(IterTy Begin, IterTy End, FuncTy Fn) {
- // Limit the number of tasks to MaxTasksPerGroup to limit job scheduling
- // overhead on large inputs.
- ptrdiff_t TaskSize = std::distance(Begin, End) / MaxTasksPerGroup;
- if (TaskSize == 0)
- TaskSize = 1;
-
- TaskGroup TG;
- while (TaskSize < std::distance(Begin, End)) {
- TG.spawn([=, &Fn] { std::for_each(Begin, Begin + TaskSize, Fn); });
- Begin += TaskSize;
- }
- std::for_each(Begin, End, Fn);
-}
-
-template <class IndexTy, class FuncTy>
-void parallel_for_each_n(IndexTy Begin, IndexTy End, FuncTy Fn) {
- // Limit the number of tasks to MaxTasksPerGroup to limit job scheduling
- // overhead on large inputs.
- ptrdiff_t TaskSize = (End - Begin) / MaxTasksPerGroup;
- if (TaskSize == 0)
- TaskSize = 1;
-
- TaskGroup TG;
- IndexTy I = Begin;
- for (; I + TaskSize < End; I += TaskSize) {
- TG.spawn([=, &Fn] {
- for (IndexTy J = I, E = I + TaskSize; J != E; ++J)
- Fn(J);
- });
- }
- for (IndexTy J = I; J < End; ++J)
- Fn(J);
-}
-
-template <class IterTy, class ResultTy, class ReduceFuncTy,
- class TransformFuncTy>
-ResultTy parallel_transform_reduce(IterTy Begin, IterTy End, ResultTy Init,
- ReduceFuncTy Reduce,
- TransformFuncTy Transform) {
- // Limit the number of tasks to MaxTasksPerGroup to limit job scheduling
- // overhead on large inputs.
- size_t NumInputs = std::distance(Begin, End);
- if (NumInputs == 0)
- return std::move(Init);
- size_t NumTasks = std::min(static_cast<size_t>(MaxTasksPerGroup), NumInputs);
- std::vector<ResultTy> Results(NumTasks, Init);
- {
- // Each task processes either TaskSize or TaskSize+1 inputs. Any inputs
- // remaining after dividing them equally amongst tasks are distributed as
- // one extra input over the first tasks.
- TaskGroup TG;
- size_t TaskSize = NumInputs / NumTasks;
- size_t RemainingInputs = NumInputs % NumTasks;
- IterTy TBegin = Begin;
- for (size_t TaskId = 0; TaskId < NumTasks; ++TaskId) {
- IterTy TEnd = TBegin + TaskSize + (TaskId < RemainingInputs ? 1 : 0);
- TG.spawn([=, &Transform, &Reduce, &Results] {
- // Reduce the result of transformation eagerly within each task.
- ResultTy R = Init;
- for (IterTy It = TBegin; It != TEnd; ++It)
- R = Reduce(R, Transform(*It));
- Results[TaskId] = R;
- });
- TBegin = TEnd;
- }
- assert(TBegin == End);
- }
-
- // Do a final reduction. There are at most 1024 tasks, so this only adds
- // constant single-threaded overhead for large inputs. Hopefully most
- // reductions are cheaper than the transformation.
- ResultTy FinalResult = std::move(Results.front());
- for (ResultTy &PartialResult :
- makeMutableArrayRef(Results.data() + 1, Results.size() - 1))
- FinalResult = Reduce(FinalResult, std::move(PartialResult));
- return std::move(FinalResult);
-}
-
-#endif
-
-} // namespace detail
-} // namespace parallel
-
-template <class RandomAccessIterator,
- class Comparator = std::less<
- typename std::iterator_traits<RandomAccessIterator>::value_type>>
-void parallelSort(RandomAccessIterator Start, RandomAccessIterator End,
- const Comparator &Comp = Comparator()) {
-#if LLVM_ENABLE_THREADS
- if (parallel::strategy.ThreadsRequested != 1) {
- parallel::detail::parallel_sort(Start, End, Comp);
- return;
- }
-#endif
- llvm::sort(Start, End, Comp);
-}
-
-template <class IterTy, class FuncTy>
-void parallelForEach(IterTy Begin, IterTy End, FuncTy Fn) {
-#if LLVM_ENABLE_THREADS
- if (parallel::strategy.ThreadsRequested != 1) {
- parallel::detail::parallel_for_each(Begin, End, Fn);
- return;
- }
-#endif
- std::for_each(Begin, End, Fn);
-}
-
-template <class FuncTy>
-void parallelForEachN(size_t Begin, size_t End, FuncTy Fn) {
-#if LLVM_ENABLE_THREADS
- if (parallel::strategy.ThreadsRequested != 1) {
- parallel::detail::parallel_for_each_n(Begin, End, Fn);
- return;
- }
-#endif
- for (size_t I = Begin; I != End; ++I)
- Fn(I);
-}
-
-template <class IterTy, class ResultTy, class ReduceFuncTy,
- class TransformFuncTy>
-ResultTy parallelTransformReduce(IterTy Begin, IterTy End, ResultTy Init,
- ReduceFuncTy Reduce,
- TransformFuncTy Transform) {
-#if LLVM_ENABLE_THREADS
- if (parallel::strategy.ThreadsRequested != 1) {
- return parallel::detail::parallel_transform_reduce(Begin, End, Init, Reduce,
- Transform);
- }
-#endif
- for (IterTy I = Begin; I != End; ++I)
- Init = Reduce(std::move(Init), Transform(*I));
- return std::move(Init);
-}
-
-// Range wrappers.
-template <class RangeTy,
- class Comparator = std::less<decltype(*std::begin(RangeTy()))>>
-void parallelSort(RangeTy &&R, const Comparator &Comp = Comparator()) {
- parallelSort(std::begin(R), std::end(R), Comp);
-}
-
-template <class RangeTy, class FuncTy>
-void parallelForEach(RangeTy &&R, FuncTy Fn) {
- parallelForEach(std::begin(R), std::end(R), Fn);
-}
-
-template <class RangeTy, class ResultTy, class ReduceFuncTy,
- class TransformFuncTy>
-ResultTy parallelTransformReduce(RangeTy &&R, ResultTy Init,
- ReduceFuncTy Reduce,
- TransformFuncTy Transform) {
- return parallelTransformReduce(std::begin(R), std::end(R), Init, Reduce,
- Transform);
-}
-
-// Parallel for-each, but with error handling.
-template <class RangeTy, class FuncTy>
-Error parallelForEachError(RangeTy &&R, FuncTy Fn) {
- // The transform_reduce algorithm requires that the initial value be copyable.
- // Error objects are uncopyable. We only need to copy initial success values,
- // so work around this mismatch via the C API. The C API represents success
- // values with a null pointer. The joinErrors discards null values and joins
- // multiple errors into an ErrorList.
- return unwrap(parallelTransformReduce(
- std::begin(R), std::end(R), wrap(Error::success()),
- [](LLVMErrorRef Lhs, LLVMErrorRef Rhs) {
- return wrap(joinErrors(unwrap(Lhs), unwrap(Rhs)));
- },
- [&Fn](auto &&V) { return wrap(Fn(V)); }));
-}
-
-} // namespace llvm
-
-#endif // LLVM_SUPPORT_PARALLEL_H
-
-#ifdef __GNUC__
-#pragma GCC diagnostic pop
-#endif