kc3-lang/harfbuzz/src/hb-atomic.hh
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Hash : 27b2e16a
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Date : 2025-04-20T04:34:40
[atomic] Make cmpexch() non-const Was a mistake. Make the affected members mutable instead.
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src/hb-atomic.hh
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/* * Copyright © 2007 Chris Wilson * Copyright © 2009,2010 Red Hat, Inc. * Copyright © 2011,2012 Google, Inc. * * This is part of HarfBuzz, a text shaping library. * * Permission is hereby granted, without written agreement and without * license or royalty fees, to use, copy, modify, and distribute this * software and its documentation for any purpose, provided that the * above copyright notice and the following two paragraphs appear in * all copies of this software. * * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH * DAMAGE. * * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND * FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS. * * Contributor(s): * Chris Wilson <chris@chris-wilson.co.uk> * Red Hat Author(s): Behdad Esfahbod * Google Author(s): Behdad Esfahbod */ #ifndef HB_ATOMIC_HH #define HB_ATOMIC_HH #include "hb.hh" #include "hb-meta.hh" /* * Atomic integers and pointers. */ /* We need external help for these */ #if defined(hb_atomic_int_impl_add) \ && defined(hb_atomic_ptr_impl_get) \ && defined(hb_atomic_ptr_impl_cmpexch) /* Defined externally, i.e. in config.h. */ #elif !defined(HB_NO_MT) && defined(__ATOMIC_ACQUIRE) /* C++11-style GCC primitives. We prefer these as they don't require linking to libstdc++ / libc++. */ #define _hb_memory_barrier() __sync_synchronize () #define hb_atomic_int_impl_add(AI, V) __atomic_fetch_add ((AI), (V), __ATOMIC_ACQ_REL) #define hb_atomic_int_impl_set_relaxed(AI, V) __atomic_store_n ((AI), (V), __ATOMIC_RELAXED) #define hb_atomic_int_impl_set(AI, V) __atomic_store_n ((AI), (V), __ATOMIC_RELEASE) #define hb_atomic_int_impl_get_relaxed(AI) __atomic_load_n ((AI), __ATOMIC_RELAXED) #define hb_atomic_int_impl_get(AI) __atomic_load_n ((AI), __ATOMIC_ACQUIRE) #define hb_atomic_ptr_impl_set_relaxed(P, V) __atomic_store_n ((P), (V), __ATOMIC_RELAXED) #define hb_atomic_ptr_impl_get_relaxed(P) __atomic_load_n ((P), __ATOMIC_RELAXED) #define hb_atomic_ptr_impl_get(P) __atomic_load_n ((P), __ATOMIC_ACQUIRE) static inline bool _hb_atomic_ptr_impl_cmplexch (const void **P, const void *O_, const void *N) { const void *O = O_; // Need lvalue return __atomic_compare_exchange_n ((void **) P, (void **) &O, (void *) N, true, __ATOMIC_ACQ_REL, __ATOMIC_RELAXED); } #define hb_atomic_ptr_impl_cmpexch(P,O,N) _hb_atomic_ptr_impl_cmplexch ((const void **) (P), (O), (N)) #elif !defined(HB_NO_MT) /* C++11 atomics. */ #include <atomic> #define _hb_memory_r_barrier() std::atomic_thread_fence(std::memory_order_acquire) #define _hb_memory_w_barrier() std::atomic_thread_fence(std::memory_order_release) #define hb_atomic_int_impl_add(AI, V) (reinterpret_cast<std::atomic<typename std::decay<decltype (*(AI))>::type> *> (AI)->fetch_add ((V), std::memory_order_acq_rel)) #define hb_atomic_int_impl_set_relaxed(AI, V) (reinterpret_cast<std::atomic<typename std::decay<decltype (*(AI))>::type> *> (AI)->store ((V), std::memory_order_relaxed)) #define hb_atomic_int_impl_set(AI, V) (reinterpret_cast<std::atomic<typename std::decay<decltype (*(AI))>::type> *> (AI)->store ((V), std::memory_order_release)) #define hb_atomic_int_impl_get_relaxed(AI) (reinterpret_cast<std::atomic<typename std::decay<decltype (*(AI))>::type> const *> (AI)->load (std::memory_order_relaxed)) #define hb_atomic_int_impl_get(AI) (reinterpret_cast<std::atomic<typename std::decay<decltype (*(AI))>::type> const *> (AI)->load (std::memory_order_acquire)) #define hb_atomic_ptr_impl_set_relaxed(P, V) (reinterpret_cast<std::atomic<void*> *> (P)->store ((V), std::memory_order_relaxed)) #define hb_atomic_ptr_impl_get_relaxed(P) (reinterpret_cast<std::atomic<void*> const *> (P)->load (std::memory_order_relaxed)) #define hb_atomic_ptr_impl_get(P) (reinterpret_cast<std::atomic<void*> *> (P)->load (std::memory_order_acquire)) static inline bool _hb_atomic_ptr_impl_cmplexch (const void **P, const void *O_, const void *N) { const void *O = O_; // Need lvalue return reinterpret_cast<std::atomic<const void*> *> (P)->compare_exchange_weak (O, N, std::memory_order_acq_rel, std::memory_order_relaxed); } #define hb_atomic_ptr_impl_cmpexch(P,O,N) _hb_atomic_ptr_impl_cmplexch ((const void **) (P), (O), (N)) #else /* defined(HB_NO_MT) */ #define hb_atomic_int_impl_add(AI, V) ((*(AI) += (V)) - (V)) #define _hb_memory_barrier() do {} while (0) #define hb_atomic_ptr_impl_cmpexch(P,O,N) (* (void **) (P) == (void *) (O) ? (* (void **) (P) = (void *) (N), true) : false) #endif /* This should never be disabled, even under HB_NO_MT. * except that MSVC gives me an internal compiler error, so disabled there. * * https://github.com/harfbuzz/harfbuzz/pull/4119 */ #ifndef _hb_compiler_memory_r_barrier #if defined(__ATOMIC_ACQUIRE) // gcc-like static inline void _hb_compiler_memory_r_barrier () { asm volatile("": : :"memory"); } #elif !defined(_MSC_VER) #include <atomic> #define _hb_compiler_memory_r_barrier() std::atomic_signal_fence (std::memory_order_acquire) #else static inline void _hb_compiler_memory_r_barrier () {} #endif #endif #ifndef _hb_memory_r_barrier #define _hb_memory_r_barrier() _hb_memory_barrier () #endif #ifndef _hb_memory_w_barrier #define _hb_memory_w_barrier() _hb_memory_barrier () #endif #ifndef hb_atomic_int_impl_set_relaxed #define hb_atomic_int_impl_set_relaxed(AI, V) (*(AI) = (V)) #endif #ifndef hb_atomic_int_impl_get_relaxed #define hb_atomic_int_impl_get_relaxed(AI) (*(AI)) #endif #ifndef hb_atomic_ptr_impl_set_relaxed #define hb_atomic_ptr_impl_set_relaxed(P, V) (*(P) = (V)) #endif #ifndef hb_atomic_ptr_impl_get_relaxed #define hb_atomic_ptr_impl_get_relaxed(P) (*(P)) #endif #ifndef hb_atomic_int_impl_set template <typename T> inline void hb_atomic_int_impl_set (T *AI, T v) { _hb_memory_w_barrier (); *AI = v; } #endif #ifndef hb_atomic_int_impl_get template <typename T> inline T hb_atomic_int_impl_get (const T *AI) { T v = *AI; _hb_memory_r_barrier (); return v; } #endif #ifndef hb_atomic_ptr_impl_get inline void *hb_atomic_ptr_impl_get (void ** const P) { void *v = *P; _hb_memory_r_barrier (); return v; } #endif template <typename T> struct hb_atomic_t { hb_atomic_t () = default; constexpr hb_atomic_t (T v) : v (v) {} hb_atomic_t& operator = (T v_) { set_relaxed (v_); return *this; } operator T () const { return get_relaxed (); } void set_relaxed (T v_) { hb_atomic_int_impl_set_relaxed (&v, v_); } void set_release (T v_) { hb_atomic_int_impl_set (&v, v_); } T get_relaxed () const { return hb_atomic_int_impl_get_relaxed (&v); } T get_acquire () const { return hb_atomic_int_impl_get (&v); } T inc () { return hb_atomic_int_impl_add (&v, 1); } T dec () { return hb_atomic_int_impl_add (&v, -1); } int operator ++ (int) { return inc (); } int operator -- (int) { return dec (); } long operator |= (long v_) { set_relaxed (get_relaxed () | v_); return *this; } T v = 0; }; template <typename T> struct hb_atomic_t<T*> { hb_atomic_t () = default; constexpr hb_atomic_t (T* v) : v (v) {} hb_atomic_t (const hb_atomic_t &other) = delete; void init (T* v_ = nullptr) { set_relaxed (v_); } void set_relaxed (T* v_) { hb_atomic_ptr_impl_set_relaxed (&v, v_); } T *get_relaxed () const { return (T *) hb_atomic_ptr_impl_get_relaxed (&v); } T *get_acquire () const { return (T *) hb_atomic_ptr_impl_get ((void **) &v); } bool cmpexch (const T *old, T *new_) { return hb_atomic_ptr_impl_cmpexch ((void **) &v, (void *) old, (void *) new_); } operator bool () const { return get_acquire () != nullptr; } T * operator -> () const { return get_acquire (); } template <typename C> operator C * () const { return get_acquire (); } T *v = nullptr; }; static inline bool hb_barrier () { _hb_compiler_memory_r_barrier (); return true; } #endif /* HB_ATOMIC_HH */