blob: 34958a257390d93ceab69a8e3c760cafb428fcba [file] [log] [blame]
//===-- 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();
}