1 //===-- ManagedStatic.cpp - Static Global wrapper -------------------------===// 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 the ManagedStatic class and llvm_shutdown(). 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "llvm/Support/ManagedStatic.h" 15 #include "llvm/Config/config.h" 16 #include "llvm/Support/Mutex.h" 17 #include "llvm/Support/MutexGuard.h" 18 #include "llvm/Support/Threading.h" 19 #include <cassert> 20 using namespace llvm; 21 22 static const ManagedStaticBase *StaticList = nullptr; 23 static sys::Mutex *ManagedStaticMutex = nullptr; 24 static llvm::once_flag mutex_init_flag; 25 initializeMutex()26static void initializeMutex() { 27 ManagedStaticMutex = new sys::Mutex(); 28 } 29 getManagedStaticMutex()30static sys::Mutex* getManagedStaticMutex() { 31 llvm::call_once(mutex_init_flag, initializeMutex); 32 return ManagedStaticMutex; 33 } 34 RegisterManagedStatic(void * (* Creator)(),void (* Deleter)(void *)) const35void ManagedStaticBase::RegisterManagedStatic(void *(*Creator)(), 36 void (*Deleter)(void*)) const { 37 assert(Creator); 38 if (llvm_is_multithreaded()) { 39 MutexGuard Lock(*getManagedStaticMutex()); 40 41 if (!Ptr.load(std::memory_order_relaxed)) { 42 void *Tmp = Creator(); 43 44 Ptr.store(Tmp, std::memory_order_release); 45 DeleterFn = Deleter; 46 47 // Add to list of managed statics. 48 Next = StaticList; 49 StaticList = this; 50 } 51 } else { 52 assert(!Ptr && !DeleterFn && !Next && 53 "Partially initialized ManagedStatic!?"); 54 Ptr = Creator(); 55 DeleterFn = Deleter; 56 57 // Add to list of managed statics. 58 Next = StaticList; 59 StaticList = this; 60 } 61 } 62 destroy() const63void ManagedStaticBase::destroy() const { 64 assert(DeleterFn && "ManagedStatic not initialized correctly!"); 65 assert(StaticList == this && 66 "Not destroyed in reverse order of construction?"); 67 // Unlink from list. 68 StaticList = Next; 69 Next = nullptr; 70 71 // Destroy memory. 72 DeleterFn(Ptr); 73 74 // Cleanup. 75 Ptr = nullptr; 76 DeleterFn = nullptr; 77 } 78 79 /// llvm_shutdown - Deallocate and destroy all ManagedStatic variables. llvm_shutdown()80void llvm::llvm_shutdown() { 81 MutexGuard Lock(*getManagedStaticMutex()); 82 83 while (StaticList) 84 StaticList->destroy(); 85 } 86