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