79 lines · cpp
1//===-- ManagedStatic.cpp - Static Global wrapper -------------------------===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8//9// This file implements the ManagedStatic class and llvm_shutdown().10//11//===----------------------------------------------------------------------===//12 13#include "llvm/Support/ManagedStatic.h"14#include "llvm/Config/config.h"15#include "llvm/Support/Threading.h"16#include <cassert>17#include <mutex>18using namespace llvm;19 20static const ManagedStaticBase *StaticList = nullptr;21 22static std::recursive_mutex *getManagedStaticMutex() {23 static std::recursive_mutex m;24 return &m;25}26 27void ManagedStaticBase::RegisterManagedStatic(void *(*Creator)(),28 void (*Deleter)(void*)) const {29 assert(Creator);30 if (llvm_is_multithreaded()) {31 std::lock_guard<std::recursive_mutex> Lock(*getManagedStaticMutex());32 33 if (!Ptr.load(std::memory_order_relaxed)) {34 void *Tmp = Creator();35 36 Ptr.store(Tmp, std::memory_order_release);37 DeleterFn = Deleter;38 39 // Add to list of managed statics.40 Next = StaticList;41 StaticList = this;42 }43 } else {44 assert(!Ptr && !DeleterFn && !Next &&45 "Partially initialized ManagedStatic!?");46 Ptr = Creator();47 DeleterFn = Deleter;48 49 // Add to list of managed statics.50 Next = StaticList;51 StaticList = this;52 }53}54 55void ManagedStaticBase::destroy() const {56 assert(DeleterFn && "ManagedStatic not initialized correctly!");57 assert(StaticList == this &&58 "Not destroyed in reverse order of construction?");59 // Unlink from list.60 StaticList = Next;61 Next = nullptr;62 63 // Destroy memory.64 DeleterFn(Ptr);65 66 // Cleanup.67 Ptr = nullptr;68 DeleterFn = nullptr;69}70 71/// llvm_shutdown - Deallocate and destroy all ManagedStatic variables.72/// IMPORTANT: it's only safe to call llvm_shutdown() in single thread,73/// without any other threads executing LLVM APIs.74/// llvm_shutdown() should be the last use of LLVM APIs.75void llvm::llvm_shutdown() {76 while (StaticList)77 StaticList->destroy();78}79