| //===-- ManagedStatic.cpp - Static Global wrapper -------------------------===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file implements the ManagedStatic class and llvm_shutdown(). |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "llvm/Support/ManagedStatic.h" |
| #include "llvm/Support/Threading.h" |
| #include <cassert> |
| #include <mutex> |
| using namespace llvm; |
| |
| static const ManagedStaticBase *StaticList = nullptr; |
| static std::recursive_mutex *ManagedStaticMutex = nullptr; |
| LLVM_DEFINE_ONCE_FLAG(mutex_init_flag); |
| |
| #if 0 |
| |
| static void initializeMutex() { |
| ManagedStaticMutex = new std::recursive_mutex(); |
| } |
| |
| static std::recursive_mutex* getManagedStaticMutex() { |
| // We need to use a function local static here, since this can get called |
| // during a static constructor and we need to guarantee that it's initialized |
| // correctly. |
| llvm::call_once(mutex_init_flag, initializeMutex); |
| return ManagedStaticMutex; |
| } |
| |
| #else |
| |
| // SwiftShader: from https://reviews.llvm.org/D83372 |
| static std::recursive_mutex *getManagedStaticMutex() { |
| static std::recursive_mutex m; |
| return &m; |
| } |
| |
| #endif |
| |
| void ManagedStaticBase::RegisterManagedStatic(void *(*Creator)(), |
| void (*Deleter)(void*)) const { |
| assert(Creator); |
| std::lock_guard<std::recursive_mutex> 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; |
| } |
| } |
| |
| 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() { |
| // SwiftShader: from https://reviews.llvm.org/D83372 |
| // This may be called after the mutex is destroyed. Instead of fixing this, |
| // don't bother locking the mutex, and require llvm_shutdown to be called from |
| // exactly one thread. |
| // std::lock_guard<std::recursive_mutex> Lock(*getManagedStaticMutex()); |
| |
| while (StaticList) |
| StaticList->destroy(); |
| } |