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/3rd_party/llvm/lib/Support/Threading.cpp

https://code.google.com/p/softart/
C++ | 147 lines | 94 code | 27 blank | 26 comment | 18 complexity | f98324331022726d95ad72c86cfbf43c MD5 | raw file
Possible License(s): LGPL-2.1, BSD-3-Clause, JSON, MPL-2.0-no-copyleft-exception, GPL-2.0, GPL-3.0, LGPL-3.0, BSD-2-Clause
  1//===-- llvm/Support/Threading.cpp- Control multithreading mode --*- C++ -*-==//
  2//
  3//                     The LLVM Compiler Infrastructure
  4//
  5// This file is distributed under the University of Illinois Open Source
  6// License. See LICENSE.TXT for details.
  7//
  8//===----------------------------------------------------------------------===//
  9//
 10// This file implements llvm_start_multithreaded() and friends.
 11//
 12//===----------------------------------------------------------------------===//
 13
 14#include "llvm/Support/Threading.h"
 15#include "llvm/Config/config.h"
 16#include "llvm/Support/Atomic.h"
 17#include "llvm/Support/Mutex.h"
 18#include <cassert>
 19
 20using namespace llvm;
 21
 22static bool multithreaded_mode = false;
 23
 24static sys::Mutex* global_lock = 0;
 25
 26bool llvm::llvm_start_multithreaded() {
 27#if LLVM_ENABLE_THREADS != 0
 28  assert(!multithreaded_mode && "Already multithreaded!");
 29  multithreaded_mode = true;
 30  global_lock = new sys::Mutex(true);
 31
 32  // We fence here to ensure that all initialization is complete BEFORE we
 33  // return from llvm_start_multithreaded().
 34  sys::MemoryFence();
 35  return true;
 36#else
 37  return false;
 38#endif
 39}
 40
 41void llvm::llvm_stop_multithreaded() {
 42#if LLVM_ENABLE_THREADS != 0
 43  assert(multithreaded_mode && "Not currently multithreaded!");
 44
 45  // We fence here to insure that all threaded operations are complete BEFORE we
 46  // return from llvm_stop_multithreaded().
 47  sys::MemoryFence();
 48
 49  multithreaded_mode = false;
 50  delete global_lock;
 51#endif
 52}
 53
 54bool llvm::llvm_is_multithreaded() {
 55  return multithreaded_mode;
 56}
 57
 58void llvm::llvm_acquire_global_lock() {
 59  if (multithreaded_mode) global_lock->acquire();
 60}
 61
 62void llvm::llvm_release_global_lock() {
 63  if (multithreaded_mode) global_lock->release();
 64}
 65
 66#if LLVM_ENABLE_THREADS != 0 && defined(HAVE_PTHREAD_H)
 67#include <pthread.h>
 68
 69struct ThreadInfo {
 70  void (*UserFn)(void *);
 71  void *UserData;
 72};
 73static void *ExecuteOnThread_Dispatch(void *Arg) {
 74  ThreadInfo *TI = reinterpret_cast<ThreadInfo*>(Arg);
 75  TI->UserFn(TI->UserData);
 76  return 0;
 77}
 78
 79void llvm::llvm_execute_on_thread(void (*Fn)(void*), void *UserData,
 80                                  unsigned RequestedStackSize) {
 81  ThreadInfo Info = { Fn, UserData };
 82  pthread_attr_t Attr;
 83  pthread_t Thread;
 84
 85  // Construct the attributes object.
 86  if (::pthread_attr_init(&Attr) != 0)
 87    return;
 88
 89  // Set the requested stack size, if given.
 90  if (RequestedStackSize != 0) {
 91    if (::pthread_attr_setstacksize(&Attr, RequestedStackSize) != 0)
 92      goto error;
 93  }
 94
 95  // Construct and execute the thread.
 96  if (::pthread_create(&Thread, &Attr, ExecuteOnThread_Dispatch, &Info) != 0)
 97    goto error;
 98
 99  // Wait for the thread and clean up.
100  ::pthread_join(Thread, 0);
101
102 error:
103  ::pthread_attr_destroy(&Attr);
104}
105#elif LLVM_ENABLE_THREADS!=0 && defined(LLVM_ON_WIN32)
106#include "Windows/Windows.h"
107#include <process.h>
108
109struct ThreadInfo {
110  void (*func)(void*);
111  void *param;
112};
113
114static unsigned __stdcall ThreadCallback(void *param) {
115  struct ThreadInfo *info = reinterpret_cast<struct ThreadInfo *>(param);
116  info->func(info->param);
117
118  return 0;
119}
120
121void llvm::llvm_execute_on_thread(void (*Fn)(void*), void *UserData,
122                                  unsigned RequestedStackSize) {
123  struct ThreadInfo param = { Fn, UserData };
124
125  HANDLE hThread = (HANDLE)::_beginthreadex(NULL,
126                                            RequestedStackSize, ThreadCallback,
127                                            &param, 0, NULL);
128
129  if (hThread) {
130    // We actually don't care whether the wait succeeds or fails, in
131    // the same way we don't care whether the pthread_join call succeeds
132    // or fails.  There's not much we could do if this were to fail. But
133    // on success, this call will wait until the thread finishes executing
134    // before returning.
135    (void)::WaitForSingleObject(hThread, INFINITE);
136    ::CloseHandle(hThread);
137  }
138}
139#else
140// Support for non-Win32, non-pthread implementation.
141void llvm::llvm_execute_on_thread(void (*Fn)(void*), void *UserData,
142                                  unsigned RequestedStackSize) {
143  (void) RequestedStackSize;
144  Fn(UserData);
145}
146
147#endif