← Back
Editing: atomic.h
/* ---------------------------------------------------------------------------- Copyright (c) 2018-2023 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. // We base the primitives on the C/C++ atomics and create a mimimal wrapper for MSVC in C compilation mode. // This is why we try to use only `uintptr_t` and `<type>*` as atomic types. // To gain better insight in the range of used atomics, we use explicitly named memory order operations // instead of passing the memory order as a parameter. // ----------------------------------------------------------------------------------------------- #if defined(__cplusplus) // Use C++ atomics #include <atomic> #define _Atomic(tp) std::atomic<tp> #define mi_atomic(name) std::atomic_##name #define mi_memory_order(name) std::memory_order_##name #if (__cplusplus >= 202002L) // c++20, see issue #571 #define MI_ATOMIC_VAR_INIT(x) x #elif !defined(ATOMIC_VAR_INIT) #define MI_ATOMIC_VAR_INIT(x) x #else #define MI_ATOMIC_VAR_INIT(x) ATOMIC_VAR_INIT(x) #endif #elif defined(_MSC_VER) // Use MSVC C wrapper for C11 atomics #define _Atomic(tp) tp #define MI_ATOMIC_VAR_INIT(x) x #define mi_atomic(name) mi_atomic_##name #define mi_memory_order(name) mi_memory_order_##name #else // Use C11 atomics #include <stdatomic.h> #define mi_atomic(name) atomic_##name #define mi_memory_order(name) memory_order_##name #if (__STDC_VERSION__ >= 201710L) // c17, see issue #735 #define MI_ATOMIC_VAR_INIT(x) x #elif !defined(ATOMIC_VAR_INIT) #define MI_ATOMIC_VAR_INIT(x) x #else #define MI_ATOMIC_VAR_INIT(x) ATOMIC_VAR_INIT(x) #endif #endif // Various defines for all used memory orders in mimalloc #define mi_atomic_cas_weak(p,expected,desired,mem_success,mem_fail) \ mi_atomic(compare_exchange_weak_explicit)(p,expected,desired,mem_success,mem_fail) #define mi_atomic_cas_strong(p,expected,desired,mem_success,mem_fail) \ mi_atomic(compare_exchange_strong_explicit)(p,expected,desired,mem_success,mem_fail) #define mi_atomic_load_acquire(p) mi_atomic(load_explicit)(p,mi_memory_order(acquire)) #define mi_atomic_load_relaxed(p) mi_atomic(load_explicit)(p,mi_memory_order(relaxed)) #define mi_atomic_store_release(p,x) mi_atomic(store_explicit)(p,x,mi_memory_order(release)) #define mi_atomic_store_relaxed(p,x) mi_atomic(store_explicit)(p,x,mi_memory_order(relaxed)) #define mi_atomic_exchange_release(p,x) mi_atomic(exchange_explicit)(p,x,mi_memory_order(release)) #define mi_atomic_exchange_acq_rel(p,x) mi_atomic(exchange_explicit)(p,x,mi_memory_order(acq_rel)) #define mi_atomic_cas_weak_release(p,exp,des) mi_atomic_cas_weak(p,exp,des,mi_memory_order(release),mi_memory_order(relaxed)) #define mi_atomic_cas_weak_acq_rel(p,exp,des) mi_atomic_cas_weak(p,exp,des,mi_memory_order(acq_rel),mi_memory_order(acquire)) #define mi_atomic_cas_strong_release(p,exp,des) mi_atomic_cas_strong(p,exp,des,mi_memory_order(release),mi_memory_order(relaxed)) #define mi_atomic_cas_strong_acq_rel(p,exp,des) mi_atomic_cas_strong(p,exp,des,mi_memory_order(acq_rel),mi_memory_order(acquire)) #define mi_atomic_add_relaxed(p,x) mi_atomic(fetch_add_explicit)(p,x,mi_memory_order(relaxed)) #define mi_atomic_sub_relaxed(p,x) mi_atomic(fetch_sub_explicit)(p,x,mi_memory_order(relaxed)) #define mi_atomic_add_acq_rel(p,x) mi_atomic(fetch_add_explicit)(p,x,mi_memory_order(acq_rel)) #define mi_atomic_sub_acq_rel(p,x) mi_atomic(fetch_sub_explicit)(p,x,mi_memory_order(acq_rel)) #define mi_atomic_and_acq_rel(p,x) mi_atomic(fetch_and_explicit)(p,x,mi_memory_order(acq_rel)) #define mi_atomic_or_acq_rel(p,x) mi_atomic(fetch_or_explicit)(p,x,mi_memory_order(acq_rel)) #define mi_atomic_increment_relaxed(p) mi_atomic_add_relaxed(p,(uintptr_t)1) #define mi_atomic_decrement_relaxed(p) mi_atomic_sub_relaxed(p,(uintptr_t)1) #define mi_atomic_increment_acq_rel(p) mi_atomic_add_acq_rel(p,(uintptr_t)1) #define mi_atomic_decrement_acq_rel(p) mi_atomic_sub_acq_rel(p,(uintptr_t)1) static inline void mi_atomic_yield(void); static inline intptr_t mi_atomic_addi(_Atomic(intptr_t)*p, intptr_t add); static inline intptr_t mi_atomic_subi(_Atomic(intptr_t)*p, intptr_t sub); #if defined(__cplusplus) || !defined(_MSC_VER) // In C++/C11 atomics we have polymorphic atomics so can use the typed `ptr` variants (where `tp` is the type of atomic value) // We use these macros so we can provide a typed wrapper in MSVC in C compilation mode as well #define mi_atomic_load_ptr_acquire(tp,p) mi_atomic_load_acquire(p) #define mi_atomic_load_ptr_relaxed(tp,p) mi_atomic_load_relaxed(p) // In C++ we need to add casts to help resolve templates if NULL is passed #if defined(__cplusplus) #define mi_atomic_store_ptr_release(tp,p,x) mi_atomic_store_release(p,(tp*)x) #define mi_atomic_store_ptr_relaxed(tp,p,x) mi_atomic_store_relaxed(p,(tp*)x) #define mi_atomic_cas_ptr_weak_release(tp,p,exp,des) mi_atomic_cas_weak_release(p,exp,(tp*)des) #define mi_atomic_cas_ptr_weak_acq_rel(tp,p,exp,des) mi_atomic_cas_weak_acq_rel(p,exp,(tp*)des) #define mi_atomic_cas_ptr_strong_release(tp,p,exp,des) mi_atomic_cas_strong_release(p,exp,(tp*)des) #define mi_atomic_exchange_ptr_release(tp,p,x) mi_atomic_exchange_release(p,(tp*)x) #define mi_atomic_exchange_ptr_acq_rel(tp,p,x) mi_atomic_exchange_acq_rel(p,(tp*)x) #else #define mi_atomic_store_ptr_release(tp,p,x) mi_atomic_store_release(p,x) #define mi_atomic_store_ptr_relaxed(tp,p,x) mi_atomic_store_relaxed(p,x) #define mi_atomic_cas_ptr_weak_release(tp,p,exp,des) mi_atomic_cas_weak_release(p,exp,des) #define mi_atomic_cas_ptr_weak_acq_rel(tp,p,exp,des) mi_atomic_cas_weak_acq_rel(p,exp,des) #define mi_atomic_cas_ptr_strong_release(tp,p,exp,des) mi_atomic_cas_strong_release(p,exp,des) #define mi_atomic_exchange_ptr_release(tp,p,x) mi_atomic_exchange_release(p,x) #define mi_atomic_exchange_ptr_acq_rel(tp,p,x) mi_atomic_exchange_acq_rel(p,x) #endif // These are used by the statistics static inline int64_t mi_atomic_addi64_relaxed(volatile int64_t* p, int64_t add) { return mi_atomic(fetch_add_explicit)((_Atomic(int64_t)*)p, add, mi_memory_order(relaxed)); } static inline void mi_atomic_maxi64_relaxed(volatile int64_t* p, int64_t x) { int64_t current = mi_atomic_load_relaxed((_Atomic(int64_t)*)p); while (current < x && !mi_atomic_cas_weak_release((_Atomic(int64_t)*)p, ¤t, x)) { /* nothing */ }; } // Used by timers #define mi_atomic_loadi64_acquire(p) mi_atomic(load_explicit)(p,mi_memory_order(acquire)) #define mi_atomic_loadi64_relaxed(p) mi_atomic(load_explicit)(p,mi_memory_order(relaxed)) #define mi_atomic_storei64_release(p,x) mi_atomic(store_explicit)(p,x,mi_memory_order(release)) #define mi_atomic_storei64_relaxed(p,x) mi_atomic(store_explicit)(p,x,mi_memory_order(relaxed)) #define mi_atomic_casi64_strong_acq_rel(p,e,d) mi_atomic_cas_strong_acq_rel(p,e,d) #define mi_atomic_addi64_acq_rel(p,i) mi_atomic_add_acq_rel(p,i) #elif defined(_MSC_VER) // MSVC C compilation wrapper that uses Interlocked operations to model C11 atomics. #define WIN32_LEAN_AND_MEAN #include <windows.h> #include <intrin.h> #ifdef _WIN64 typedef LONG64 msc_intptr_t; #define MI_64(f) f##64 #else typedef LONG msc_intptr_t; #define MI_64(f) f #endif typedef enum mi_memory_order_e { mi_memory_order_relaxed, mi_memory_order_consume, mi_memory_order_acquire, mi_memory_order_release, mi_memory_order_acq_rel, mi_memory_order_seq_cst } mi_memory_order; static inline uintptr_t mi_atomic_fetch_add_explicit(_Atomic(uintptr_t)*p, uintptr_t add, mi_memory_order mo) { (void)(mo); return (uintptr_t)MI_64(_InterlockedExchangeAdd)((volatile msc_intptr_t*)p, (msc_intptr_t)add); } static inline uintptr_t mi_atomic_fetch_sub_explicit(_Atomic(uintptr_t)*p, uintptr_t sub, mi_memory_order mo) { (void)(mo); return (uintptr_t)MI_64(_InterlockedExchangeAdd)((volatile msc_intptr_t*)p, -((msc_intptr_t)sub)); } static inline uintptr_t mi_atomic_fetch_and_explicit(_Atomic(uintptr_t)*p, uintptr_t x, mi_memory_order mo) { (void)(mo); return (uintptr_t)MI_64(_InterlockedAnd)((volatile msc_intptr_t*)p, (msc_intptr_t)x); } static inline uintptr_t mi_atomic_fetch_or_explicit(_Atomic(uintptr_t)*p, uintptr_t x, mi_memory_order mo) { (void)(mo); return (uintptr_t)MI_64(_InterlockedOr)((volatile msc_intptr_t*)p, (msc_intptr_t)x); } static inline bool mi_atomic_compare_exchange_strong_explicit(_Atomic(uintptr_t)*p, uintptr_t* expected, uintptr_t desired, mi_memory_order mo1, mi_memory_order mo2) { (void)(mo1); (void)(mo2); uintptr_t read = (uintptr_t)MI_64(_InterlockedCompareExchange)((volatile msc_intptr_t*)p, (msc_intptr_t)desired, (msc_intptr_t)(*expected)); if (read == *expected) { return true; } else { *expected = read; return false; } } static inline bool mi_atomic_compare_exchange_weak_explicit(_Atomic(uintptr_t)*p, uintptr_t* expected, uintptr_t desired, mi_memory_order mo1, mi_memory_order mo2) { return mi_atomic_compare_exchange_strong_explicit(p, expected, desired, mo1, mo2); } static inline uintptr_t mi_atomic_exchange_explicit(_Atomic(uintptr_t)*p, uintptr_t exchange, mi_memory_order mo) { (void)(mo); return (uintptr_t)MI_64(_InterlockedExchange)((volatile msc_intptr_t*)p, (msc_intptr_t)exchange); } static inline void mi_atomic_thread_fence(mi_memory_order mo) { (void)(mo); _Atomic(uintptr_t) x = 0; mi_atomic_exchange_explicit(&x, 1, mo); } static inline uintptr_t mi_atomic_load_explicit(_Atomic(uintptr_t) const* p, mi_memory_order mo) { (void)(mo); #if defined(_M_IX86) || defined(_M_X64) return *p; #else uintptr_t x = *p; if (mo > mi_memory_order_relaxed) { while (!mi_atomic_compare_exchange_weak_explicit((_Atomic(uintptr_t)*)p, &x, x, mo, mi_memory_order_relaxed)) { /* nothing */ }; } return x; #endif } static inline void mi_atomic_store_explicit(_Atomic(uintptr_t)*p, uintptr_t x, mi_memory_order mo) { (void)(mo); #if defined(_M_IX86) || defined(_M_X64) *p = x; #else mi_atomic_exchange_explicit(p, x, mo); #endif } static inline int64_t mi_atomic_loadi64_explicit(_Atomic(int64_t)*p, mi_memory_order mo) { (void)(mo); #if defined(_M_X64) return *p; #else int64_t old = *p; int64_t x = old; while ((old = InterlockedCompareExchange64(p, x, old)) != x) { x = old; } return x; #endif } static inline void mi_atomic_storei64_explicit(_Atomic(int64_t)*p, int64_t x, mi_memory_order mo) { (void)(mo); #if defined(x_M_IX86) || defined(_M_X64) *p = x; #else InterlockedExchange64(p, x); #endif } // These are used by the statistics static inline int64_t mi_atomic_addi64_relaxed(volatile _Atomic(int64_t)*p, int64_t add) { #ifdef _WIN64 return (int64_t)mi_atomic_addi((int64_t*)p, add); #else int64_t current; int64_t sum; do { current = *p; sum = current + add; } while (_InterlockedCompareExchange64(p, sum, current) != current); return current; #endif } static inline void mi_atomic_maxi64_relaxed(volatile _Atomic(int64_t)*p, int64_t x) { int64_t current; do { current = *p; } while (current < x && _InterlockedCompareExchange64(p, x, current) != current); } static inline void mi_atomic_addi64_acq_rel(volatile _Atomic(int64_t*)p, int64_t i) { mi_atomic_addi64_relaxed(p, i); } static inline bool mi_atomic_casi64_strong_acq_rel(volatile _Atomic(int64_t*)p, int64_t* exp, int64_t des) { int64_t read = _InterlockedCompareExchange64(p, des, *exp); if (read == *exp) { return true; } else { *exp = read; return false; } } // The pointer macros cast to `uintptr_t`. #define mi_atomic_load_ptr_acquire(tp,p) (tp*)mi_atomic_load_acquire((_Atomic(uintptr_t)*)(p)) #define mi_atomic_load_ptr_relaxed(tp,p) (tp*)mi_atomic_load_relaxed((_Atomic(uintptr_t)*)(p)) #define mi_atomic_store_ptr_release(tp,p,x) mi_atomic_store_release((_Atomic(uintptr_t)*)(p),(uintptr_t)(x)) #define mi_atomic_store_ptr_relaxed(tp,p,x) mi_atomic_store_relaxed((_Atomic(uintptr_t)*)(p),(uintptr_t)(x)) #define mi_atomic_cas_ptr_weak_release(tp,p,exp,des) mi_atomic_cas_weak_release((_Atomic(uintptr_t)*)(p),(uintptr_t*)exp,(uintptr_t)des) #define mi_atomic_cas_ptr_weak_acq_rel(tp,p,exp,des) mi_atomic_cas_weak_acq_rel((_Atomic(uintptr_t)*)(p),(uintptr_t*)exp,(uintptr_t)des) #define mi_atomic_cas_ptr_strong_release(tp,p,exp,des) mi_atomic_cas_strong_release((_Atomic(uintptr_t)*)(p),(uintptr_t*)exp,(uintptr_t)des) #define mi_atomic_exchange_ptr_release(tp,p,x) (tp*)mi_atomic_exchange_release((_Atomic(uintptr_t)*)(p),(uintptr_t)x) #define mi_atomic_exchange_ptr_acq_rel(tp,p,x) (tp*)mi_atomic_exchange_acq_rel((_Atomic(uintptr_t)*)(p),(uintptr_t)x) #define mi_atomic_loadi64_acquire(p) mi_atomic(loadi64_explicit)(p,mi_memory_order(acquire)) #define mi_atomic_loadi64_relaxed(p) mi_atomic(loadi64_explicit)(p,mi_memory_order(relaxed)) #define mi_atomic_storei64_release(p,x) mi_atomic(storei64_explicit)(p,x,mi_memory_order(release)) #define mi_atomic_storei64_relaxed(p,x) mi_atomic(storei64_explicit)(p,x,mi_memory_order(relaxed)) #endif // Atomically add a signed value; returns the previous value. static inline intptr_t mi_atomic_addi(_Atomic(intptr_t)*p, intptr_t add) { return (intptr_t)mi_atomic_add_acq_rel((_Atomic(uintptr_t)*)p, (uintptr_t)add); } // Atomically subtract a signed value; returns the previous value. static inline intptr_t mi_atomic_subi(_Atomic(intptr_t)*p, intptr_t sub) { return (intptr_t)mi_atomic_addi(p, -sub); } typedef _Atomic(uintptr_t) mi_atomic_once_t; // Returns true only on the first invocation static inline bool mi_atomic_once( mi_atomic_once_t* once ) { if (mi_atomic_load_relaxed(once) != 0) return false; // quick test uintptr_t expected = 0; return mi_atomic_cas_strong_acq_rel(once, &expected, (uintptr_t)1); // try to set to 1 } typedef _Atomic(uintptr_t) mi_atomic_guard_t; // Allows only one thread to execute at a time #define mi_atomic_guard(guard) \ uintptr_t _mi_guard_expected = 0; \ for(bool _mi_guard_once = true; \ _mi_guard_once && mi_atomic_cas_strong_acq_rel(guard,&_mi_guard_expected,(uintptr_t)1); \ (mi_atomic_store_release(guard,(uintptr_t)0), _mi_guard_once = false) ) // Yield #if defined(__cplusplus) #include <thread> static inline void mi_atomic_yield(void) { std::this_thread::yield(); } #elif defined(_WIN32) #define WIN32_LEAN_AND_MEAN #include <windows.h> static inline void mi_atomic_yield(void) { YieldProcessor(); } #elif defined(__SSE2__) #include <emmintrin.h> static inline void mi_atomic_yield(void) { _mm_pause(); } #elif (defined(__GNUC__) || defined(__clang__)) && \ (defined(__x86_64__) || defined(__i386__) || \ defined(__aarch64__) || defined(__arm__) || \ defined(__powerpc__) || defined(__ppc__) || defined(__PPC__) || defined(__POWERPC__)) #if defined(__x86_64__) || defined(__i386__) static inline void mi_atomic_yield(void) { __asm__ volatile ("pause" ::: "memory"); } #elif defined(__aarch64__) static inline void mi_atomic_yield(void) { __asm__ volatile("wfe"); } #elif defined(__arm__) #if __ARM_ARCH >= 7 static inline void mi_atomic_yield(void) { __asm__ volatile("yield" ::: "memory"); } #else static inline void mi_atomic_yield(void) { __asm__ volatile ("nop" ::: "memory"); } #endif #elif defined(__powerpc__) || defined(__ppc__) || defined(__PPC__) || defined(__POWERPC__) #ifdef __APPLE__ static inline void mi_atomic_yield(void) { __asm__ volatile ("or r27,r27,r27" ::: "memory"); } #else static inline void mi_atomic_yield(void) { __asm__ __volatile__ ("or 27,27,27" ::: "memory"); } #endif #endif #elif defined(__sun) // Fallback for other archs #include <synch.h> static inline void mi_atomic_yield(void) { smt_pause(); } #elif defined(__wasi__) #include <sched.h> static inline void mi_atomic_yield(void) { sched_yield(); } #else #include <unistd.h> static inline void mi_atomic_yield(void) { sleep(0); } #endif #endif // __MIMALLOC_ATOMIC_H
Save File
Cancel