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[wpiutil] Remove unused ManagedStatic class (#4358)

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We migrated to magic statics for lazy construction like the following:
```cpp
class Singleton {
  static Singleton& GetSingleton() {
    static Singleton instance;
    return instance;
  }
};
```
This commit is contained in:
Tyler Veness
2022-08-17 18:04:42 -07:00
committed by GitHub
parent ac9be78e27
commit ea6b1d8449
4 changed files with 0 additions and 261 deletions
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1
upstream_utils/update_llvm.py
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@@ -60,7 +60,6 @@ def run_global_replacements(wpiutil_llvm_files):
# Replace llvm_unreachable() with wpi_unreachable()
content = content.replace("llvm_unreachable", "wpi_unreachable")
content = content.replace("llvm_shutdown", "wpi_shutdown")
content = content.replace("llvm_is_multithreaded()", "1")

77
wpiutil/src/main/native/thirdparty/llvm/cpp/llvm/ManagedStatic.cpp vendored
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@@ -1,77 +0,0 @@
//===-- 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 wpi_shutdown().
//
//===----------------------------------------------------------------------===//
#include "wpi/ManagedStatic.h"
#include "wpi/mutex.h"
#include <cassert>
#include <mutex>
using namespace wpi;
static const ManagedStaticBase *StaticList = nullptr;
static wpi::mutex *getManagedStaticMutex() {
static wpi::mutex m;
return &m;
}
void ManagedStaticBase::RegisterManagedStatic(void *(*Creator)(),
void (*Deleter)(void*)) const {
assert(Creator);
if (1) {
std::scoped_lock 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;
}
/// wpi_shutdown - Deallocate and destroy all ManagedStatic variables.
/// IMPORTANT: it's only safe to call wpi_shutdown() in single thread,
/// without any other threads executing LLVM APIs.
/// wpi_shutdown() should be the last use of LLVM APIs.
void wpi::wpi_shutdown() {
while (StaticList)
StaticList->destroy();
}

125
wpiutil/src/main/native/thirdparty/llvm/include/wpi/ManagedStatic.h vendored
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@@ -1,125 +0,0 @@
//===-- llvm/Support/ManagedStatic.h - Static Global wrapper ----*- C++ -*-===//
//
// 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 defines the ManagedStatic class and the wpi_shutdown() function.
//
//===----------------------------------------------------------------------===//
#ifndef WPIUTIL_WPI_MANAGEDSTATIC_H
#define WPIUTIL_WPI_MANAGEDSTATIC_H
#include <atomic>
#include <cstddef>
namespace wpi {
/// object_creator - Helper method for ManagedStatic.
template <class C> struct object_creator {
static void *call() { return new C(); }
};
/// object_deleter - Helper method for ManagedStatic.
///
template <typename T> struct object_deleter {
static void call(void *Ptr) { delete (T *)Ptr; }
};
template <typename T, size_t N> struct object_deleter<T[N]> {
static void call(void *Ptr) { delete[](T *)Ptr; }
};
// ManagedStatic must be initialized to zero, and it must *not* have a dynamic
// initializer because managed statics are often created while running other
// dynamic initializers. In standard C++11, the best way to accomplish this is
// with a constexpr default constructor. However, different versions of the
// Visual C++ compiler have had bugs where, even though the constructor may be
// constexpr, a dynamic initializer may be emitted depending on optimization
// settings. For the affected versions of MSVC, use the old linker
// initialization pattern of not providing a constructor and leaving the fields
// uninitialized. See http://llvm.org/PR41367 for details.
#if !defined(_MSC_VER) || (_MSC_VER >= 1925) || defined(__clang__)
#define LLVM_USE_CONSTEXPR_CTOR
#endif
/// ManagedStaticBase - Common base class for ManagedStatic instances.
class ManagedStaticBase {
protected:
#ifdef LLVM_USE_CONSTEXPR_CTOR
mutable std::atomic<void *> Ptr{};
mutable void (*DeleterFn)(void *) = nullptr;
mutable const ManagedStaticBase *Next = nullptr;
#else
// This should only be used as a static variable, which guarantees that this
// will be zero initialized.
mutable std::atomic<void *> Ptr;
mutable void (*DeleterFn)(void *);
mutable const ManagedStaticBase *Next;
#endif
void RegisterManagedStatic(void *(*creator)(), void (*deleter)(void*)) const;
public:
#ifdef LLVM_USE_CONSTEXPR_CTOR
constexpr ManagedStaticBase() = default;
#endif
/// isConstructed - Return true if this object has not been created yet.
bool isConstructed() const { return Ptr != nullptr; }
void destroy() const;
};
/// ManagedStatic - This transparently changes the behavior of global statics to
/// be lazily constructed on demand (good for reducing startup times of dynamic
/// libraries that link in LLVM components) and for making destruction be
/// explicit through the wpi_shutdown() function call.
///
template <class C, class Creator = object_creator<C>,
class Deleter = object_deleter<C>>
class ManagedStatic : public ManagedStaticBase {
public:
// Accessors.
C &operator*() {
void *Tmp = Ptr.load(std::memory_order_acquire);
if (!Tmp)
RegisterManagedStatic(Creator::call, Deleter::call);
return *static_cast<C *>(Ptr.load(std::memory_order_relaxed));
}
C *operator->() { return &**this; }
const C &operator*() const {
void *Tmp = Ptr.load(std::memory_order_acquire);
if (!Tmp)
RegisterManagedStatic(Creator::call, Deleter::call);
return *static_cast<C *>(Ptr.load(std::memory_order_relaxed));
}
const C *operator->() const { return &**this; }
// Extract the instance, leaving the ManagedStatic uninitialized. The
// user is then responsible for the lifetime of the returned instance.
C *claim() {
return static_cast<C *>(Ptr.exchange(nullptr));
}
};
/// wpi_shutdown - Deallocate and destroy all ManagedStatic variables.
void wpi_shutdown();
/// wpi_shutdown_obj - This is a simple helper class that calls
/// wpi_shutdown() when it is destroyed.
struct wpi_shutdown_obj {
wpi_shutdown_obj() = default;
~wpi_shutdown_obj() { wpi_shutdown(); }
};
} // end namespace wpi
#endif // WPIUTIL_WPI_MANAGEDSTATIC_H

58
wpiutil/src/test/native/ManagedStaticTest.cpp
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@@ -1,58 +0,0 @@
// Copyright (c) FIRST and other WPILib contributors.
// Open Source Software; you can modify and/or share it under the terms of
// the WPILib BSD license file in the root directory of this project.
#include "wpi/ManagedStatic.h" // NOLINT(build/include_order)
#include "gtest/gtest.h"
static int refCount = 0;
struct StaticTestClass {
StaticTestClass() { refCount++; }
~StaticTestClass() { refCount--; }
void Func() {}
};
namespace wpi {
TEST(ManagedStaticTest, LazyDoesNotInitialize) {
{
refCount = 0;
wpi::ManagedStatic<StaticTestClass> managedStatic;
(void)managedStatic;
ASSERT_EQ(refCount, 0);
}
ASSERT_EQ(refCount, 0);
wpi_shutdown();
}
TEST(ManagedStaticTest, LazyInitDoesntDestruct) {
{
refCount = 0;
wpi::ManagedStatic<StaticTestClass> managedStatic;
ASSERT_EQ(refCount, 0);
managedStatic->Func();
ASSERT_EQ(refCount, 1);
}
ASSERT_EQ(refCount, 1);
wpi_shutdown();
ASSERT_EQ(refCount, 0);
}
TEST(ManagedStaticTest, EagerInit) {
{
refCount = 0;
StaticTestClass* test = new StaticTestClass{};
ASSERT_EQ(refCount, 1); // NOLINT
wpi::ManagedStatic<StaticTestClass> managedStatic(
test, [](void* val) { delete static_cast<StaticTestClass*>(val); });
ASSERT_EQ(refCount, 1);
managedStatic->Func();
ASSERT_EQ(refCount, 1);
}
ASSERT_EQ(refCount, 1);
wpi_shutdown();
ASSERT_EQ(refCount, 0);
}
} // namespace wpi