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llvm-mirror/lib/Support/ManagedStatic.cpp
Chandler Carruth ae65e281f3 Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636
2019-01-19 08:50:56 +00:00

85 lines
2.3 KiB
C++

//===-- ManagedStatic.cpp - Static Global wrapper -------------------------===//
//
// 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 implements the ManagedStatic class and llvm_shutdown().
//
//===----------------------------------------------------------------------===//
#include "llvm/Support/ManagedStatic.h"
#include "llvm/Config/config.h"
#include "llvm/Support/Mutex.h"
#include "llvm/Support/MutexGuard.h"
#include "llvm/Support/Threading.h"
#include <cassert>
using namespace llvm;
static const ManagedStaticBase *StaticList = nullptr;
static sys::Mutex *ManagedStaticMutex = nullptr;
static llvm::once_flag mutex_init_flag;
static void initializeMutex() {
ManagedStaticMutex = new sys::Mutex();
}
static sys::Mutex* getManagedStaticMutex() {
llvm::call_once(mutex_init_flag, initializeMutex);
return ManagedStaticMutex;
}
void ManagedStaticBase::RegisterManagedStatic(void *(*Creator)(),
void (*Deleter)(void*)) const {
assert(Creator);
if (llvm_is_multithreaded()) {
MutexGuard Lock(*getManagedStaticMutex());
if (!Ptr.load(std::memory_order_relaxed)) {
void *Tmp = Creator();
Ptr.store(Tmp, std::memory_order_release);
DeleterFn = Deleter;
// Add to list of managed statics.
Next = StaticList;
StaticList = this;
}
} else {
assert(!Ptr && !DeleterFn && !Next &&
"Partially initialized ManagedStatic!?");
Ptr = Creator();
DeleterFn = Deleter;
// Add to list of managed statics.
Next = StaticList;
StaticList = this;
}
}
void ManagedStaticBase::destroy() const {
assert(DeleterFn && "ManagedStatic not initialized correctly!");
assert(StaticList == this &&
"Not destroyed in reverse order of construction?");
// Unlink from list.
StaticList = Next;
Next = nullptr;
// Destroy memory.
DeleterFn(Ptr);
// Cleanup.
Ptr = nullptr;
DeleterFn = nullptr;
}
/// llvm_shutdown - Deallocate and destroy all ManagedStatic variables.
void llvm::llvm_shutdown() {
MutexGuard Lock(*getManagedStaticMutex());
while (StaticList)
StaticList->destroy();
}