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llvm-mirror/lib/Support/ManagedStatic.cpp
Maksym Wezdecki abe2655fe0 Fix for memory leak reported by Valgrind
If llvm so lib is dlopened and dlclosed several times, then memory leak can be observed, reported by Valgrind.

This patch fixes the issue.

Reviewed By: lattner, dblaikie

Differential Revision: https://reviews.llvm.org/D83372
2021-03-16 11:01:31 -07:00

79 lines
2.3 KiB
C++

//===-- 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 *getManagedStaticMutex() {
static std::recursive_mutex m;
return &m;
}
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.
/// IMPORTANT: it's only safe to call llvm_shutdown() in single thread,
/// without any other threads executing LLVM APIs.
/// llvm_shutdown() should be the last use of LLVM APIs.
void llvm::llvm_shutdown() {
while (StaticList)
StaticList->destroy();
}