mozjs_sys 0.67.1

System crate for the Mozilla SpiderMonkey JavaScript engine.
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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 * vim: set ts=8 sts=2 et sw=2 tw=80:
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef jit_AtomicOp_h
#define jit_AtomicOp_h

namespace js {
namespace jit {

// Types of atomic operation, shared by MIR and LIR.

enum AtomicOp {
  AtomicFetchAddOp,
  AtomicFetchSubOp,
  AtomicFetchAndOp,
  AtomicFetchOrOp,
  AtomicFetchXorOp
};

// Memory barrier types, shared by MIR and LIR.
//
// MembarSynchronizing is here because some platforms can make the
// distinction (DSB vs DMB on ARM, SYNC vs parameterized SYNC on MIPS)
// but there's been no reason to use it yet.

enum MemoryBarrierBits {
  MembarLoadLoad = 1,
  MembarLoadStore = 2,
  MembarStoreStore = 4,
  MembarStoreLoad = 8,

  MembarSynchronizing = 16,

  // For validity testing
  MembarNobits = 0,
  MembarAllbits = 31,
};

static inline constexpr MemoryBarrierBits operator|(MemoryBarrierBits a,
                                                    MemoryBarrierBits b) {
  return MemoryBarrierBits(int(a) | int(b));
}

static inline constexpr MemoryBarrierBits operator&(MemoryBarrierBits a,
                                                    MemoryBarrierBits b) {
  return MemoryBarrierBits(int(a) & int(b));
}

static inline constexpr MemoryBarrierBits operator~(MemoryBarrierBits a) {
  return MemoryBarrierBits(~int(a));
}

// Standard barrier bits for a full barrier.
static constexpr MemoryBarrierBits MembarFull =
    MembarLoadLoad | MembarLoadStore | MembarStoreLoad | MembarStoreStore;

// Standard sets of barrier bits for atomic loads and stores.
// See http://gee.cs.oswego.edu/dl/jmm/cookbook.html for more.
static constexpr MemoryBarrierBits MembarBeforeLoad = MembarNobits;
static constexpr MemoryBarrierBits MembarAfterLoad =
    MembarLoadLoad | MembarLoadStore;
static constexpr MemoryBarrierBits MembarBeforeStore = MembarStoreStore;
static constexpr MemoryBarrierBits MembarAfterStore = MembarStoreLoad;

struct Synchronization {
  const MemoryBarrierBits barrierBefore;
  const MemoryBarrierBits barrierAfter;

  constexpr Synchronization(MemoryBarrierBits before, MemoryBarrierBits after)
      : barrierBefore(before), barrierAfter(after) {}

  static Synchronization None() {
    return Synchronization(MemoryBarrierBits(MembarNobits),
                           MemoryBarrierBits(MembarNobits));
  }

  static Synchronization Full() {
    return Synchronization(MembarFull, MembarFull);
  }

  static Synchronization Load() {
    return Synchronization(MembarBeforeLoad, MembarAfterLoad);
  }

  static Synchronization Store() {
    return Synchronization(MembarBeforeStore, MembarAfterStore);
  }

  bool isNone() const { return (barrierBefore | barrierAfter) == MembarNobits; }
};

}  // namespace jit
}  // namespace js

#endif /* jit_AtomicOp_h */