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//===-- llvm/Support/Threading.cpp- Control multithreading mode --*- C++ -*-==//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements llvm_start_multithreaded() and friends.
//
//===----------------------------------------------------------------------===//
#include "llvm/Support/Threading.h"
#include "llvm/Support/Atomic.h"
#include "llvm/Support/Mutex.h"
#include "llvm/Config/config.h"
#include <cassert>
using namespace llvm;
static bool multithreaded_mode = false;
static sys::Mutex* global_lock = 0;
bool llvm::llvm_start_multithreaded() {
#ifdef LLVM_MULTITHREADED
assert(!multithreaded_mode && "Already multithreaded!");
multithreaded_mode = true;
global_lock = new sys::Mutex(true);
// We fence here to ensure that all initialization is complete BEFORE we
// return from llvm_start_multithreaded().
sys::MemoryFence();
return true;
#else
return false;
#endif
}
void llvm::llvm_stop_multithreaded() {
#ifdef LLVM_MULTITHREADED
assert(multithreaded_mode && "Not currently multithreaded!");
// We fence here to insure that all threaded operations are complete BEFORE we
// return from llvm_stop_multithreaded().
sys::MemoryFence();
multithreaded_mode = false;
delete global_lock;
#endif
}
bool llvm::llvm_is_multithreaded() {
return multithreaded_mode;
}
void llvm::llvm_acquire_global_lock() {
if (multithreaded_mode) global_lock->acquire();
}
void llvm::llvm_release_global_lock() {
if (multithreaded_mode) global_lock->release();
}
#if defined(LLVM_MULTITHREADED) && defined(HAVE_PTHREAD_H)
#include <pthread.h>
struct ThreadInfo {
void (*UserFn)(void *);
void *UserData;
};
static void *ExecuteOnThread_Dispatch(void *Arg) {
ThreadInfo *TI = reinterpret_cast<ThreadInfo*>(Arg);
TI->UserFn(TI->UserData);
return 0;
}
void llvm::llvm_execute_on_thread(void (*Fn)(void*), void *UserData,
unsigned RequestedStackSize) {
ThreadInfo Info = { Fn, UserData };
pthread_attr_t Attr;
pthread_t Thread;
// Construct the attributes object.
if (::pthread_attr_init(&Attr) != 0)
return;
// Set the requested stack size, if given.
if (RequestedStackSize != 0) {
if (::pthread_attr_setstacksize(&Attr, RequestedStackSize) != 0)
goto error;
}
// Construct and execute the thread.
if (::pthread_create(&Thread, &Attr, ExecuteOnThread_Dispatch, &Info) != 0)
goto error;
// Wait for the thread and clean up.
::pthread_join(Thread, 0);
error:
::pthread_attr_destroy(&Attr);
}
#else
// No non-pthread implementation, currently.
void llvm::llvm_execute_on_thread(void (*Fn)(void*), void *UserData,
unsigned RequestedStackSize) {
(void) RequestedStackSize;
Fn(UserData);
}
#endif
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