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gcc can't seem to figure out that the address of a member variable of AK::Atomic<u32> in AtomicRefCounted cannot be null when fetch_sub-ing. Add a bogus condition to convince the compiler that it can't be null.
455 lines
14 KiB
C++
455 lines
14 KiB
C++
/*
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* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#pragma once
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#include <AK/Concepts.h>
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#include <AK/Platform.h>
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#include <AK/Types.h>
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namespace AK {
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static inline void atomic_signal_fence(MemoryOrder order) noexcept
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{
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return __atomic_signal_fence(order);
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}
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static inline void atomic_thread_fence(MemoryOrder order) noexcept
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{
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return __atomic_thread_fence(order);
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}
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static inline void full_memory_barrier() noexcept
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{
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atomic_signal_fence(AK::MemoryOrder::memory_order_acq_rel);
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atomic_thread_fence(AK::MemoryOrder::memory_order_acq_rel);
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}
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template<typename T>
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static inline T atomic_exchange(T volatile* var, T desired, MemoryOrder order = memory_order_seq_cst) noexcept
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{
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return __atomic_exchange_n(var, desired, order);
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}
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template<typename T, typename V = RemoveVolatile<T>>
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static inline V* atomic_exchange(T volatile** var, V* desired, MemoryOrder order = memory_order_seq_cst) noexcept
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{
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return __atomic_exchange_n(var, desired, order);
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}
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template<typename T, typename V = RemoveVolatile<T>>
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static inline V* atomic_exchange(T volatile** var, nullptr_t, MemoryOrder order = memory_order_seq_cst) noexcept
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{
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return __atomic_exchange_n(const_cast<V**>(var), nullptr, order);
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}
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template<typename T>
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[[nodiscard]] static inline bool atomic_compare_exchange_strong(T volatile* var, T& expected, T desired, MemoryOrder order = memory_order_seq_cst) noexcept
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{
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if (order == memory_order_acq_rel || order == memory_order_release)
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return __atomic_compare_exchange_n(var, &expected, desired, false, memory_order_release, memory_order_acquire);
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return __atomic_compare_exchange_n(var, &expected, desired, false, order, order);
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}
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template<typename T, typename V = RemoveVolatile<T>>
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[[nodiscard]] static inline bool atomic_compare_exchange_strong(T volatile** var, V*& expected, V* desired, MemoryOrder order = memory_order_seq_cst) noexcept
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{
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if (order == memory_order_acq_rel || order == memory_order_release)
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return __atomic_compare_exchange_n(var, &expected, desired, false, memory_order_release, memory_order_acquire);
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return __atomic_compare_exchange_n(var, &expected, desired, false, order, order);
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}
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template<typename T, typename V = RemoveVolatile<T>>
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[[nodiscard]] static inline bool atomic_compare_exchange_strong(T volatile** var, V*& expected, nullptr_t, MemoryOrder order = memory_order_seq_cst) noexcept
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{
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if (order == memory_order_acq_rel || order == memory_order_release)
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return __atomic_compare_exchange_n(const_cast<V**>(var), &expected, nullptr, false, memory_order_release, memory_order_acquire);
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return __atomic_compare_exchange_n(const_cast<V**>(var), &expected, nullptr, false, order, order);
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}
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template<typename T>
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static inline T atomic_fetch_add(T volatile* var, T val, MemoryOrder order = memory_order_seq_cst) noexcept
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{
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return __atomic_fetch_add(var, val, order);
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}
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template<typename T>
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static inline T atomic_fetch_sub(T volatile* var, T val, MemoryOrder order = memory_order_seq_cst) noexcept
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{
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return __atomic_fetch_sub(var, val, order);
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}
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template<typename T>
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static inline T atomic_fetch_and(T volatile* var, T val, MemoryOrder order = memory_order_seq_cst) noexcept
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{
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return __atomic_fetch_and(var, val, order);
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}
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template<typename T>
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static inline T atomic_fetch_or(T volatile* var, T val, MemoryOrder order = memory_order_seq_cst) noexcept
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{
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return __atomic_fetch_or(var, val, order);
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}
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template<typename T>
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static inline T atomic_fetch_xor(T volatile* var, T val, MemoryOrder order = memory_order_seq_cst) noexcept
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{
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return __atomic_fetch_xor(var, val, order);
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}
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template<typename T>
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static inline T atomic_load(T volatile* var, MemoryOrder order = memory_order_seq_cst) noexcept
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{
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return __atomic_load_n(var, order);
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}
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template<typename T, typename V = RemoveVolatile<T>>
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static inline V* atomic_load(T volatile** var, MemoryOrder order = memory_order_seq_cst) noexcept
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{
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return __atomic_load_n(const_cast<V**>(var), order);
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}
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template<typename T>
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static inline void atomic_store(T volatile* var, T desired, MemoryOrder order = memory_order_seq_cst) noexcept
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{
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__atomic_store_n(var, desired, order);
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}
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template<typename T, typename V = RemoveVolatile<T>>
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static inline void atomic_store(T volatile** var, V* desired, MemoryOrder order = memory_order_seq_cst) noexcept
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{
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__atomic_store_n(var, desired, order);
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}
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template<typename T, typename V = RemoveVolatile<T>>
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static inline void atomic_store(T volatile** var, nullptr_t, MemoryOrder order = memory_order_seq_cst) noexcept
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{
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__atomic_store_n(const_cast<V**>(var), nullptr, order);
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}
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template<typename T>
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static inline bool atomic_is_lock_free(T volatile* ptr = nullptr) noexcept
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{
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return __atomic_is_lock_free(sizeof(T), ptr);
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}
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template<typename T, MemoryOrder DefaultMemoryOrder = AK::MemoryOrder::memory_order_seq_cst>
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class Atomic {
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// FIXME: This should work through concepts/requires clauses, but according to the compiler,
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// "IsIntegral is not more specialized than IsFundamental".
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// Additionally, Enums are not fundamental types except that they behave like them in every observable way.
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static_assert(IsFundamental<T> | IsEnum<T>, "Atomic doesn't support non-primitive types, because it relies on compiler intrinsics. If you put non-primitives into it, you'll get linker errors like \"undefined reference to __atomic_store\".");
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T m_value { 0 };
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public:
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Atomic() noexcept = default;
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Atomic& operator=(Atomic const&) volatile = delete;
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Atomic& operator=(Atomic&&) volatile = delete;
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Atomic(Atomic const&) = delete;
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Atomic(Atomic&&) = delete;
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constexpr Atomic(T val) noexcept
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: m_value(val)
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{
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}
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T volatile* ptr() noexcept
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{
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return &m_value;
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}
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T exchange(T desired, MemoryOrder order = DefaultMemoryOrder) volatile noexcept
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{
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// We use this hack to prevent unnecessary initialization, even if T has a default constructor.
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// NOTE: Will need to investigate if it pessimizes the generated assembly.
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alignas(T) u8 buffer[sizeof(T)];
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T* ret = reinterpret_cast<T*>(buffer);
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__atomic_exchange(&m_value, &desired, ret, order);
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return *ret;
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}
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[[nodiscard]] bool compare_exchange_strong(T& expected, T desired, MemoryOrder order = DefaultMemoryOrder) volatile noexcept
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{
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if (order == memory_order_acq_rel || order == memory_order_release)
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return __atomic_compare_exchange(&m_value, &expected, &desired, false, memory_order_release, memory_order_acquire);
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return __atomic_compare_exchange(&m_value, &expected, &desired, false, order, order);
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}
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ALWAYS_INLINE operator T() const volatile noexcept
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{
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return load();
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}
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ALWAYS_INLINE T load(MemoryOrder order = DefaultMemoryOrder) const volatile noexcept
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{
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alignas(T) u8 buffer[sizeof(T)];
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T* ret = reinterpret_cast<T*>(buffer);
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__atomic_load(&m_value, ret, order);
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return *ret;
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}
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// NOLINTNEXTLINE(misc-unconventional-assign-operator) We want operator= to exchange the value, so returning an object of type Atomic& here does not make sense
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ALWAYS_INLINE T operator=(T desired) volatile noexcept
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{
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store(desired);
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return desired;
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}
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ALWAYS_INLINE void store(T desired, MemoryOrder order = DefaultMemoryOrder) volatile noexcept
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{
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__atomic_store(&m_value, &desired, order);
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}
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ALWAYS_INLINE bool is_lock_free() const volatile noexcept
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{
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return __atomic_is_lock_free(sizeof(m_value), &m_value);
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}
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};
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template<Integral T, MemoryOrder DefaultMemoryOrder>
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class Atomic<T, DefaultMemoryOrder> {
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T m_value { 0 };
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public:
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Atomic() noexcept = default;
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Atomic& operator=(Atomic const&) volatile = delete;
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Atomic& operator=(Atomic&&) volatile = delete;
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Atomic(Atomic const&) = delete;
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Atomic(Atomic&&) = delete;
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constexpr Atomic(T val) noexcept
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: m_value(val)
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{
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}
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T volatile* ptr() noexcept
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{
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return &m_value;
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}
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T exchange(T desired, MemoryOrder order = DefaultMemoryOrder) volatile noexcept
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{
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return __atomic_exchange_n(&m_value, desired, order);
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}
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[[nodiscard]] bool compare_exchange_strong(T& expected, T desired, MemoryOrder order = DefaultMemoryOrder) volatile noexcept
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{
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if (order == memory_order_acq_rel || order == memory_order_release)
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return __atomic_compare_exchange_n(&m_value, &expected, desired, false, memory_order_release, memory_order_acquire);
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return __atomic_compare_exchange_n(&m_value, &expected, desired, false, order, order);
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}
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ALWAYS_INLINE T operator++() volatile noexcept
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{
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return fetch_add(1) + 1;
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}
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ALWAYS_INLINE T operator++(int) volatile noexcept
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{
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return fetch_add(1);
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}
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ALWAYS_INLINE T operator+=(T val) volatile noexcept
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{
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return fetch_add(val) + val;
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}
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ALWAYS_INLINE T fetch_add(T val, MemoryOrder order = DefaultMemoryOrder) volatile noexcept
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{
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return __atomic_fetch_add(&m_value, val, order);
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}
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ALWAYS_INLINE T operator--() volatile noexcept
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{
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return fetch_sub(1) - 1;
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}
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ALWAYS_INLINE T operator--(int) volatile noexcept
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{
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return fetch_sub(1);
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}
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ALWAYS_INLINE T operator-=(T val) volatile noexcept
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{
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return fetch_sub(val) - val;
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}
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ALWAYS_INLINE T fetch_sub(T val, MemoryOrder order = DefaultMemoryOrder) volatile noexcept
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{
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T volatile* ptr = &m_value;
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// FIXME: GCC > 12 will wrongly warn on -Wstringop-overflow here with ASAN+UBSAN
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#if defined(AK_COMPILER_GCC) && defined(HAS_ADDRESS_SANITIZER)
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if (!ptr)
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__builtin_unreachable();
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#endif
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return __atomic_fetch_sub(ptr, val, order);
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}
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ALWAYS_INLINE T operator&=(T val) volatile noexcept
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{
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return fetch_and(val) & val;
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}
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ALWAYS_INLINE T fetch_and(T val, MemoryOrder order = DefaultMemoryOrder) volatile noexcept
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{
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return __atomic_fetch_and(&m_value, val, order);
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}
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ALWAYS_INLINE T operator|=(T val) volatile noexcept
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{
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return fetch_or(val) | val;
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}
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ALWAYS_INLINE T fetch_or(T val, MemoryOrder order = DefaultMemoryOrder) volatile noexcept
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{
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return __atomic_fetch_or(&m_value, val, order);
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}
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ALWAYS_INLINE T operator^=(T val) volatile noexcept
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{
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return fetch_xor(val) ^ val;
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}
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ALWAYS_INLINE T fetch_xor(T val, MemoryOrder order = DefaultMemoryOrder) volatile noexcept
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{
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return __atomic_fetch_xor(&m_value, val, order);
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}
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ALWAYS_INLINE operator T() const volatile noexcept
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{
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return load();
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}
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ALWAYS_INLINE T load(MemoryOrder order = DefaultMemoryOrder) const volatile noexcept
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{
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return __atomic_load_n(&m_value, order);
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}
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// NOLINTNEXTLINE(misc-unconventional-assign-operator) We want operator= to exchange the value, so returning an object of type Atomic& here does not make sense
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ALWAYS_INLINE T operator=(T desired) volatile noexcept
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{
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store(desired);
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return desired;
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}
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ALWAYS_INLINE void store(T desired, MemoryOrder order = DefaultMemoryOrder) volatile noexcept
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{
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__atomic_store_n(&m_value, desired, order);
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}
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ALWAYS_INLINE bool is_lock_free() const volatile noexcept
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{
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return __atomic_is_lock_free(sizeof(m_value), &m_value);
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}
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};
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template<typename T, MemoryOrder DefaultMemoryOrder>
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class Atomic<T*, DefaultMemoryOrder> {
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T* m_value { nullptr };
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public:
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Atomic() noexcept = default;
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Atomic& operator=(Atomic const&) volatile = delete;
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Atomic& operator=(Atomic&&) volatile = delete;
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Atomic(Atomic const&) = delete;
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Atomic(Atomic&&) = delete;
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constexpr Atomic(T* val) noexcept
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: m_value(val)
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{
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}
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T* volatile* ptr() noexcept
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{
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return &m_value;
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}
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T* exchange(T* desired, MemoryOrder order = DefaultMemoryOrder) volatile noexcept
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{
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return __atomic_exchange_n(&m_value, desired, order);
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}
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[[nodiscard]] bool compare_exchange_strong(T*& expected, T* desired, MemoryOrder order = DefaultMemoryOrder) volatile noexcept
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{
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if (order == memory_order_acq_rel || order == memory_order_release)
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return __atomic_compare_exchange_n(&m_value, &expected, desired, false, memory_order_release, memory_order_acquire);
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return __atomic_compare_exchange_n(&m_value, &expected, desired, false, order, order);
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}
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T* operator++() volatile noexcept
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{
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return fetch_add(1) + 1;
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}
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T* operator++(int) volatile noexcept
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{
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return fetch_add(1);
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}
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T* operator+=(ptrdiff_t val) volatile noexcept
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{
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return fetch_add(val) + val;
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}
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T* fetch_add(ptrdiff_t val, MemoryOrder order = DefaultMemoryOrder) volatile noexcept
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{
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return __atomic_fetch_add(&m_value, val * sizeof(*m_value), order);
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}
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T* operator--() volatile noexcept
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{
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return fetch_sub(1) - 1;
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}
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T* operator--(int) volatile noexcept
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{
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return fetch_sub(1);
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}
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T* operator-=(ptrdiff_t val) volatile noexcept
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{
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return fetch_sub(val) - val;
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}
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T* fetch_sub(ptrdiff_t val, MemoryOrder order = DefaultMemoryOrder) volatile noexcept
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{
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return __atomic_fetch_sub(&m_value, val * sizeof(*m_value), order);
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}
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operator T*() const volatile noexcept
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{
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return load();
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}
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T* load(MemoryOrder order = DefaultMemoryOrder) const volatile noexcept
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{
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return __atomic_load_n(&m_value, order);
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}
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// NOLINTNEXTLINE(misc-unconventional-assign-operator) We want operator= to exchange the value, so returning an object of type Atomic& here does not make sense
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T* operator=(T* desired) volatile noexcept
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{
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store(desired);
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return desired;
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}
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void store(T* desired, MemoryOrder order = DefaultMemoryOrder) volatile noexcept
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{
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__atomic_store_n(&m_value, desired, order);
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}
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bool is_lock_free() const volatile noexcept
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{
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return __atomic_is_lock_free(sizeof(m_value), &m_value);
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}
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};
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}
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#if USING_AK_GLOBALLY
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using AK::Atomic;
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using AK::full_memory_barrier;
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#endif
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