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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;
#if 0
static void initializeMutex() {
ManagedStaticMutex = new std::recursive_mutex();
}
static std::recursive_mutex *getManagedStaticMutex() {
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);
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() {
// 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();
}