117 lines
3.6 KiB
C++
117 lines
3.6 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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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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#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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if (ThreadsRequested == 0)
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return MaxThreadCount;
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if (!Limit)
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return ThreadsRequested;
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return std::min((unsigned)MaxThreadCount, ThreadsRequested);
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}
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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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// Must be included after Threading.inc to provide definition for llvm::thread
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// because FreeBSD's condvar.h (included by user.h) misuses the "thread"
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// keyword.
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#include "llvm/Support/thread.h"
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#if defined(__APPLE__)
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// Darwin's default stack size for threads except the main one is only 512KB,
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// which is not enough for some/many normal LLVM compilations. This implements
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// the same interface as std::thread but requests the same stack size as the
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// main thread (8MB) before creation.
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const llvm::Optional<unsigned> llvm::thread::DefaultStackSize = 8 * 1024 * 1024;
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#else
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const llvm::Optional<unsigned> llvm::thread::DefaultStackSize = None;
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#endif
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#endif
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Optional<ThreadPoolStrategy>
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llvm::get_threadpool_strategy(StringRef Num, ThreadPoolStrategy Default) {
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if (Num == "all")
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return llvm::hardware_concurrency();
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if (Num.empty())
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return Default;
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unsigned V;
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if (Num.getAsInteger(10, V))
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return None; // malformed 'Num' value
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if (V == 0)
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return Default;
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// Do not take the Default into account. This effectively disables
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// heavyweight_hardware_concurrency() if the user asks for any number of
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// threads on the cmd-line.
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ThreadPoolStrategy S = llvm::hardware_concurrency();
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S.ThreadsRequested = V;
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return S;
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}
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