/* ---------------------------------------------------------------------------- Copyright (c) 2018, Microsoft Research, Daan Leijen This is free software; you can redistribute it and/or modify it under the terms of the MIT license. A copy of the license can be found in the file "LICENSE" at the root of this distribution. -----------------------------------------------------------------------------*/ #pragma once #ifndef MIMALLOC_ATOMIC_H #define MIMALLOC_ATOMIC_H // ------------------------------------------------------ // Atomics // We need to be portable between C, C++, and MSVC. // ------------------------------------------------------ #if defined(_MSC_VER) #define _Atomic(tp) tp #define ATOMIC_VAR_INIT(x) x #elif defined(__cplusplus) #include #define _Atomic(tp) std::atomic #else #include #endif #define mi_atomic_cast(tp,x) (volatile _Atomic(tp)*)(x) // ------------------------------------------------------ // Atomic operations specialized for mimalloc // ------------------------------------------------------ // Atomically add a 64-bit value; returns the previous value. // Note: not using _Atomic(int64_t) as it is only used for statistics. static inline void mi_atomic_add64(volatile int64_t* p, int64_t add); // Atomically add a value; returns the previous value. Memory ordering is relaxed. static inline intptr_t mi_atomic_add(volatile _Atomic(intptr_t)* p, intptr_t add); // Atomically compare and exchange a value; returns `true` if successful. // May fail spuriously. Memory ordering as release on success, and relaxed on failure. // (Note: expected and desired are in opposite order from atomic_compare_exchange) static inline bool mi_atomic_cas_weak(volatile _Atomic(uintptr_t)* p, uintptr_t desired, uintptr_t expected); // Atomically compare and exchange a value; returns `true` if successful. // Memory ordering is acquire-release // (Note: expected and desired are in opposite order from atomic_compare_exchange) static inline bool mi_atomic_cas_strong(volatile _Atomic(uintptr_t)* p, uintptr_t desired, uintptr_t expected); // Atomically exchange a value. Memory ordering is acquire-release. static inline uintptr_t mi_atomic_exchange(volatile _Atomic(uintptr_t)* p, uintptr_t exchange); // Atomically read a value. Memory ordering is relaxed. static inline uintptr_t mi_atomic_read_relaxed(const volatile _Atomic(uintptr_t)* p); // Atomically read a value. Memory ordering is acquire. static inline uintptr_t mi_atomic_read(const volatile _Atomic(uintptr_t)* p); // Atomically write a value. Memory ordering is release. static inline void mi_atomic_write(volatile _Atomic(uintptr_t)* p, uintptr_t x); // Yield static inline void mi_atomic_yield(void); // Atomically add a value; returns the previous value. static inline uintptr_t mi_atomic_addu(volatile _Atomic(uintptr_t)* p, uintptr_t add) { return (uintptr_t)mi_atomic_add((volatile _Atomic(intptr_t)*)p, (intptr_t)add); } // Atomically subtract a value; returns the previous value. static inline uintptr_t mi_atomic_subu(volatile _Atomic(uintptr_t)* p, uintptr_t sub) { return (uintptr_t)mi_atomic_add((volatile _Atomic(intptr_t)*)p, -((intptr_t)sub)); } // Atomically increment a value; returns the incremented result. static inline uintptr_t mi_atomic_increment(volatile _Atomic(uintptr_t)* p) { return mi_atomic_addu(p, 1); } // Atomically decrement a value; returns the decremented result. static inline uintptr_t mi_atomic_decrement(volatile _Atomic(uintptr_t)* p) { return mi_atomic_subu(p, 1); } // Atomically read a pointer; Memory order is relaxed. static inline void* mi_atomic_read_ptr_relaxed(volatile _Atomic(void*) const * p) { return (void*)mi_atomic_read_relaxed((const volatile _Atomic(uintptr_t)*)p); } // Atomically read a pointer; Memory order is acquire. static inline void* mi_atomic_read_ptr(volatile _Atomic(void*) const * p) { return (void*)mi_atomic_read((const volatile _Atomic(uintptr_t)*)p); } // Atomically write a pointer static inline void mi_atomic_write_ptr(volatile _Atomic(void*)* p, void* x) { mi_atomic_write((volatile _Atomic(uintptr_t)*)p, (uintptr_t)x ); } // Atomically compare and exchange a pointer; returns `true` if successful. May fail spuriously. // (Note: expected and desired are in opposite order from atomic_compare_exchange) static inline bool mi_atomic_cas_ptr_weak(volatile _Atomic(void*)* p, void* desired, void* expected) { return mi_atomic_cas_weak((volatile _Atomic(uintptr_t)*)p, (uintptr_t)desired, (uintptr_t)expected); } // Atomically compare and exchange a pointer; returns `true` if successful. // (Note: expected and desired are in opposite order from atomic_compare_exchange) static inline bool mi_atomic_cas_ptr_strong(volatile _Atomic(void*)* p, void* desired, void* expected) { return mi_atomic_cas_strong((volatile _Atomic(uintptr_t)*)p, (uintptr_t)desired, (uintptr_t)expected); } // Atomically exchange a pointer value. static inline void* mi_atomic_exchange_ptr(volatile _Atomic(void*)* p, void* exchange) { return (void*)mi_atomic_exchange((volatile _Atomic(uintptr_t)*)p, (uintptr_t)exchange); } #ifdef _MSC_VER #define WIN32_LEAN_AND_MEAN #include #include #ifdef _WIN64 typedef LONG64 msc_intptr_t; #define RC64(f) f##64 #else typedef LONG msc_intptr_t; #define RC64(f) f #endif static inline intptr_t mi_atomic_add(volatile _Atomic(intptr_t)* p, intptr_t add) { return (intptr_t)RC64(_InterlockedExchangeAdd)((volatile msc_intptr_t*)p, (msc_intptr_t)add); } static inline bool mi_atomic_cas_strong(volatile _Atomic(uintptr_t)* p, uintptr_t desired, uintptr_t expected) { return (expected == RC64(_InterlockedCompareExchange)((volatile msc_intptr_t*)p, (msc_intptr_t)desired, (msc_intptr_t)expected)); } static inline bool mi_atomic_cas_weak(volatile _Atomic(uintptr_t)* p, uintptr_t desired, uintptr_t expected) { return mi_atomic_cas_strong(p,desired,expected); } static inline uintptr_t mi_atomic_exchange(volatile _Atomic(uintptr_t)* p, uintptr_t exchange) { return (uintptr_t)RC64(_InterlockedExchange)((volatile msc_intptr_t*)p, (msc_intptr_t)exchange); } static inline uintptr_t mi_atomic_read(volatile _Atomic(uintptr_t) const* p) { return *p; } static inline uintptr_t mi_atomic_read_relaxed(volatile _Atomic(uintptr_t) const* p) { return mi_atomic_read(p); } static inline void mi_atomic_write(volatile _Atomic(uintptr_t)* p, uintptr_t x) { mi_atomic_exchange(p,x); } static inline void mi_atomic_yield(void) { YieldProcessor(); } static inline void mi_atomic_add64(volatile _Atomic(int64_t)* p, int64_t add) { #ifdef _WIN64 mi_atomic_add(p,add); #else int64_t current; int64_t sum; do { current = *p; sum = current + add; } while (_InterlockedCompareExchange64(p, sum, current) != current); #endif } #else #ifdef __cplusplus #define MI_USING_STD using namespace std; #else #define MI_USING_STD #endif static inline void mi_atomic_add64(volatile int64_t* p, int64_t add) { MI_USING_STD atomic_fetch_add_explicit((volatile _Atomic(int64_t)*)p, add, memory_order_relaxed); } static inline intptr_t mi_atomic_add(volatile _Atomic(intptr_t)* p, intptr_t add) { MI_USING_STD return atomic_fetch_add_explicit(p, add, memory_order_relaxed); } static inline bool mi_atomic_cas_weak(volatile _Atomic(uintptr_t)* p, uintptr_t desired, uintptr_t expected) { MI_USING_STD return atomic_compare_exchange_weak_explicit(p, &expected, desired, memory_order_release, memory_order_relaxed); } static inline bool mi_atomic_cas_strong(volatile _Atomic(uintptr_t)* p, uintptr_t desired, uintptr_t expected) { MI_USING_STD return atomic_compare_exchange_strong_explicit(p, &expected, desired, memory_order_acq_rel, memory_order_relaxed); } static inline uintptr_t mi_atomic_exchange(volatile _Atomic(uintptr_t)* p, uintptr_t exchange) { MI_USING_STD return atomic_exchange_explicit(p, exchange, memory_order_acq_rel); } static inline uintptr_t mi_atomic_read_relaxed(const volatile _Atomic(uintptr_t)* p) { MI_USING_STD return atomic_load_explicit((volatile _Atomic(uintptr_t)*) p, memory_order_relaxed); } static inline uintptr_t mi_atomic_read(const volatile _Atomic(uintptr_t)* p) { MI_USING_STD return atomic_load_explicit((volatile _Atomic(uintptr_t)*) p, memory_order_acquire); } static inline void mi_atomic_write(volatile _Atomic(uintptr_t)* p, uintptr_t x) { MI_USING_STD return atomic_store_explicit(p, x, memory_order_release); } #if defined(__cplusplus) #include static inline void mi_atomic_yield(void) { std::this_thread::yield(); } #elif (defined(__GNUC__) || defined(__clang__)) && \ (defined(__x86_64__) || defined(__i386__) || defined(__arm__) || defined(__aarch64__)) #if defined(__x86_64__) || defined(__i386__) static inline void mi_atomic_yield(void) { asm volatile ("pause" ::: "memory"); } #elif defined(__arm__) || defined(__aarch64__) static inline void mi_atomic_yield(void) { asm volatile("yield"); } #endif #elif defined(__wasi__) #include static inline void mi_atomic_yield() { sched_yield(); } #else #include static inline void mi_atomic_yield(void) { sleep(0); } #endif #endif #endif // __MIMALLOC_ATOMIC_H