forked from OSchip/llvm-project
135 lines
4.1 KiB
C++
135 lines
4.1 KiB
C++
//===-- llvm/Support/Threading.cpp- Control multithreading mode --*- C++ -*-==//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file defines helper functions for running LLVM in a multi-threaded
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// environment.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Support/Threading.h"
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#include "llvm/ADT/Optional.h"
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#include "llvm/Config/config.h"
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#include "llvm/Support/Host.h"
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#include <cassert>
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#include <errno.h>
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#include <stdlib.h>
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#include <string.h>
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using namespace llvm;
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//===----------------------------------------------------------------------===//
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//=== WARNING: Implementation here must contain only TRULY operating system
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//=== independent code.
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//===----------------------------------------------------------------------===//
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bool llvm::llvm_is_multithreaded() {
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#if LLVM_ENABLE_THREADS != 0
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return true;
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#else
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return false;
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#endif
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}
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#if LLVM_ENABLE_THREADS == 0 || \
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(!defined(_WIN32) && !defined(HAVE_PTHREAD_H))
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// Support for non-Win32, non-pthread implementation.
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void llvm::llvm_execute_on_thread(void (*Fn)(void *), void *UserData,
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llvm::Optional<unsigned> StackSizeInBytes) {
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(void)StackSizeInBytes;
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Fn(UserData);
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}
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uint64_t llvm::get_threadid() { return 0; }
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uint32_t llvm::get_max_thread_name_length() { return 0; }
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void llvm::set_thread_name(const Twine &Name) {}
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void llvm::get_thread_name(SmallVectorImpl<char> &Name) { Name.clear(); }
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llvm::BitVector llvm::get_thread_affinity_mask() { return {}; }
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unsigned llvm::ThreadPoolStrategy::compute_thread_count() const {
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// When threads are disabled, ensure clients will loop at least once.
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return 1;
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}
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#if LLVM_ENABLE_THREADS == 0
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void llvm::llvm_execute_on_thread_async(
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llvm::unique_function<void()> Func,
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llvm::Optional<unsigned> StackSizeInBytes) {
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(void)Func;
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(void)StackSizeInBytes;
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report_fatal_error("Spawning a detached thread doesn't make sense with no "
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"threading support");
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}
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#else
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// Support for non-Win32, non-pthread implementation.
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void llvm::llvm_execute_on_thread_async(
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llvm::unique_function<void()> Func,
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llvm::Optional<unsigned> StackSizeInBytes) {
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(void)StackSizeInBytes;
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std::thread(std::move(Func)).detach();
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}
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#endif
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#else
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int computeHostNumHardwareThreads();
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unsigned llvm::ThreadPoolStrategy::compute_thread_count() const {
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int MaxThreadCount = UseHyperThreads ? computeHostNumHardwareThreads()
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: sys::getHostNumPhysicalCores();
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if (MaxThreadCount <= 0)
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MaxThreadCount = 1;
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// No need to create more threads than there are hardware threads, it would
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// uselessly induce more context-switching and cache eviction.
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if (!ThreadsRequested || ThreadsRequested > (unsigned)MaxThreadCount)
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return MaxThreadCount;
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return ThreadsRequested;
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}
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namespace {
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struct SyncThreadInfo {
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void (*UserFn)(void *);
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void *UserData;
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};
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using AsyncThreadInfo = llvm::unique_function<void()>;
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enum class JoiningPolicy { Join, Detach };
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} // namespace
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// Include the platform-specific parts of this class.
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#ifdef LLVM_ON_UNIX
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#include "Unix/Threading.inc"
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#endif
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#ifdef _WIN32
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#include "Windows/Threading.inc"
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#endif
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void llvm::llvm_execute_on_thread(void (*Fn)(void *), void *UserData,
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llvm::Optional<unsigned> StackSizeInBytes) {
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SyncThreadInfo Info = {Fn, UserData};
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llvm_execute_on_thread_impl(threadFuncSync, &Info, StackSizeInBytes,
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JoiningPolicy::Join);
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}
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void llvm::llvm_execute_on_thread_async(
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llvm::unique_function<void()> Func,
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llvm::Optional<unsigned> StackSizeInBytes) {
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llvm_execute_on_thread_impl(&threadFuncAsync,
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new AsyncThreadInfo(std::move(Func)),
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StackSizeInBytes, JoiningPolicy::Detach);
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}
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#endif
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