| //===-- llvm/Support/Threading.cpp- Control multithreading mode --*- C++ -*-==// |
| // |
| // 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 |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file defines helper functions for running LLVM in a multi-threaded |
| // environment. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "llvm/Support/Threading.h" |
| #include "llvm/ADT/Optional.h" |
| #include "llvm/Config/config.h" |
| #include "llvm/Support/Host.h" |
| |
| #include <cassert> |
| #include <errno.h> |
| #include <stdlib.h> |
| #include <string.h> |
| |
| using namespace llvm; |
| |
| //===----------------------------------------------------------------------===// |
| //=== WARNING: Implementation here must contain only TRULY operating system |
| //=== independent code. |
| //===----------------------------------------------------------------------===// |
| |
| bool llvm::llvm_is_multithreaded() { |
| #if LLVM_ENABLE_THREADS != 0 |
| return true; |
| #else |
| return false; |
| #endif |
| } |
| |
| #if LLVM_ENABLE_THREADS == 0 || \ |
| (!defined(_WIN32) && !defined(HAVE_PTHREAD_H)) |
| uint64_t llvm::get_threadid() { return 0; } |
| |
| uint32_t llvm::get_max_thread_name_length() { return 0; } |
| |
| void llvm::set_thread_name(const Twine &Name) {} |
| |
| void llvm::get_thread_name(SmallVectorImpl<char> &Name) { Name.clear(); } |
| |
| llvm::BitVector llvm::get_thread_affinity_mask() { return {}; } |
| |
| unsigned llvm::ThreadPoolStrategy::compute_thread_count() const { |
| // When threads are disabled, ensure clients will loop at least once. |
| return 1; |
| } |
| |
| #else |
| |
| int computeHostNumHardwareThreads(); |
| |
| unsigned llvm::ThreadPoolStrategy::compute_thread_count() const { |
| int MaxThreadCount = UseHyperThreads ? computeHostNumHardwareThreads() |
| : sys::getHostNumPhysicalCores(); |
| if (MaxThreadCount <= 0) |
| MaxThreadCount = 1; |
| if (ThreadsRequested == 0) |
| return MaxThreadCount; |
| if (!Limit) |
| return ThreadsRequested; |
| return std::min((unsigned)MaxThreadCount, ThreadsRequested); |
| } |
| |
| // Include the platform-specific parts of this class. |
| #ifdef LLVM_ON_UNIX |
| #include "Unix/Threading.inc" |
| #endif |
| #ifdef _WIN32 |
| #include "Windows/Threading.inc" |
| #endif |
| |
| // Must be included after Threading.inc to provide definition for llvm::thread |
| // because FreeBSD's condvar.h (included by user.h) misuses the "thread" |
| // keyword. |
| #include "llvm/Support/thread.h" |
| |
| #if defined(__APPLE__) |
| // Darwin's default stack size for threads except the main one is only 512KB, |
| // which is not enough for some/many normal LLVM compilations. This implements |
| // the same interface as std::thread but requests the same stack size as the |
| // main thread (8MB) before creation. |
| const llvm::Optional<unsigned> llvm::thread::DefaultStackSize = 8 * 1024 * 1024; |
| #else |
| const llvm::Optional<unsigned> llvm::thread::DefaultStackSize = None; |
| #endif |
| |
| |
| #endif |
| |
| Optional<ThreadPoolStrategy> |
| llvm::get_threadpool_strategy(StringRef Num, ThreadPoolStrategy Default) { |
| if (Num == "all") |
| return llvm::hardware_concurrency(); |
| if (Num.empty()) |
| return Default; |
| unsigned V; |
| if (Num.getAsInteger(10, V)) |
| return None; // malformed 'Num' value |
| if (V == 0) |
| return Default; |
| |
| // Do not take the Default into account. This effectively disables |
| // heavyweight_hardware_concurrency() if the user asks for any number of |
| // threads on the cmd-line. |
| ThreadPoolStrategy S = llvm::hardware_concurrency(); |
| S.ThreadsRequested = V; |
| return S; |
| } |