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//===-- 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/Threading.h" 
#include <cassert> 
#include <mutex> 
using namespace llvm; 
 
static const ManagedStaticBase *StaticList = nullptr; 
static std::recursive_mutex *ManagedStaticMutex = nullptr; 
static llvm::once_flag mutex_init_flag; 
 
static void initializeMutex() { 
  ManagedStaticMutex = new std::recursive_mutex(); 
} 
 
static std::recursive_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()) { 
    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; 
    } 
  } 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() { 
  std::lock_guard<std::recursive_mutex> Lock(*getManagedStaticMutex()); 
 
  while (StaticList) 
    StaticList->destroy(); 
}