Quelle  AtomicOperations-mips-shared.h

/* 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/. */

/* For documentation, see jit/AtomicOperations.h */

#ifndef jit_mips_shared_AtomicOperations_mips_shared_h
#define jit_mips_shared_AtomicOperations_mips_shared_h

#include "mozilla/Assertions.h"

#include "builtin/AtomicsObject.h"
#include "vm/Uint8Clamped.h"

#if !defined(__clang__) && !defined(__GNUC__)
#  error "This file only for gcc-compatible compilers"
#endif

inline bool js::jit::AtomicOperations::hasAtomic8() { return true; }

inline bool js::jit::AtomicOperations::isLockfree8() {
  MOZ_ASSERT(__atomic_always_lock_free(sizeof(int8_t), 0));
  MOZ_ASSERT(__atomic_always_lock_free(sizeof(int16_t), 0));
  MOZ_ASSERT(__atomic_always_lock_free(sizeof(int32_t), 0));
  MOZ_ASSERT(__atomic_always_lock_free(sizeof(int64_t), 0));
  return true;
}

inline void js::jit::AtomicOperations::fenceSeqCst() {
  __atomic_thread_fence(__ATOMIC_SEQ_CST);
}

namespace js {
namespace jit {

inline void AtomicPause() { asm volatile("sync" ::: "memory"); }

}  // namespace jit
}  // namespace js

inline void js::jit::AtomicOperations::pause() { AtomicPause(); }

template <typename T>
inline T js::jit::AtomicOperations::loadSeqCst(T* addr) {
  static_assert(sizeof(T) <= sizeof(void*),
                "atomics supported up to pointer size only");
  T v;
  __atomic_load(addr, &v, __ATOMIC_SEQ_CST);
  return v;
}

template <typename T>
inline void js::jit::AtomicOperations::storeSeqCst(T* addr, T val) {
  static_assert(sizeof(T) <= sizeof(void*),
                "atomics supported up to pointer size only");
  __atomic_store(addr, &val, __ATOMIC_SEQ_CST);
}

template <typename T>
inline T js::jit::AtomicOperations::compareExchangeSeqCst(T* addr, T oldval,
                                                          T newval) {
  static_assert(sizeof(T) <= sizeof(void*),
                "atomics supported up to pointer size only");
  __atomic_compare_exchange(addr, &oldval, &newval, false, __ATOMIC_SEQ_CST,
                            __ATOMIC_SEQ_CST);
  return oldval;
}

template <typename T>
inline T js::jit::AtomicOperations::fetchAddSeqCst(T* addr, T val) {
  static_assert(sizeof(T) <= sizeof(void*),
                "atomics supported up to pointer size only");
  return __atomic_fetch_add(addr, val, __ATOMIC_SEQ_CST);
}

template <typename T>
inline T js::jit::AtomicOperations::fetchSubSeqCst(T* addr, T val) {
  static_assert(sizeof(T) <= sizeof(void*),
                "atomics supported up to pointer size only");
  return __atomic_fetch_sub(addr, val, __ATOMIC_SEQ_CST);
}

template <typename T>
inline T js::jit::AtomicOperations::fetchAndSeqCst(T* addr, T val) {
  static_assert(sizeof(T) <= sizeof(void*),
                "atomics supported up to pointer size only");
  return __atomic_fetch_and(addr, val, __ATOMIC_SEQ_CST);
}

template <typename T>
inline T js::jit::AtomicOperations::fetchOrSeqCst(T* addr, T val) {
  static_assert(sizeof(T) <= sizeof(void*),
                "atomics supported up to pointer size only");
  return __atomic_fetch_or(addr, val, __ATOMIC_SEQ_CST);
}

template <typename T>
inline T js::jit::AtomicOperations::fetchXorSeqCst(T* addr, T val) {
  static_assert(sizeof(T) <= sizeof(void*),
                "atomics supported up to pointer size only");
  return __atomic_fetch_xor(addr, val, __ATOMIC_SEQ_CST);
}

template <typename T>
inline T js::jit::AtomicOperations::loadSafeWhenRacy(T* addr) {
  static_assert(sizeof(T) <= sizeof(void*),
                "atomics supported up to pointer size only");
  T v;
  __atomic_load(addr, &v, __ATOMIC_RELAXED);
  return v;
}

namespace js {
namespace jit {

template <>
inline uint8_clamped js::jit::AtomicOperations::loadSafeWhenRacy(
    uint8_clamped* addr) {
  uint8_t v;
  __atomic_load((uint8_t*)addr, &v, __ATOMIC_RELAXED);
  return uint8_clamped(v);
}

template <>
inline float js::jit::AtomicOperations::loadSafeWhenRacy(float* addr) {
  return *addr;
}

template <>
inline double js::jit::AtomicOperations::loadSafeWhenRacy(double* addr) {
  return *addr;
}

}  // namespace jit
}  // namespace js

template <typename T>
inline void js::jit::AtomicOperations::storeSafeWhenRacy(T* addr, T val) {
  static_assert(sizeof(T) <= sizeof(void*),
                "atomics supported up to pointer size only");
  __atomic_store(addr, &val, __ATOMIC_RELAXED);
}

namespace js {
namespace jit {

template <>
inline void js::jit::AtomicOperations::storeSafeWhenRacy(uint8_clamped* addr,
                                                         uint8_clamped val) {
  __atomic_store((uint8_t*)addr, (uint8_t*)&val, __ATOMIC_RELAXED);
}

template <>
inline void js::jit::AtomicOperations::storeSafeWhenRacy(float* addr,
                                                         float val) {
  *addr = val;
}

template <>
inline void js::jit::AtomicOperations::storeSafeWhenRacy(double* addr,
                                                         double val) {
  *addr = val;
}

}  // namespace jit
}  // namespace js

inline void js::jit::AtomicOperations::memcpySafeWhenRacy(void* dest,
                                                          const void* src,
                                                          size_t nbytes) {
  MOZ_ASSERT(!((char*)dest <= (char*)src && (char*)src < (char*)dest + nbytes));
  MOZ_ASSERT(!((char*)src <= (char*)dest && (char*)dest < (char*)src + nbytes));
  ::memcpy(dest, src, nbytes);
}

inline void js::jit::AtomicOperations::memmoveSafeWhenRacy(void* dest,
                                                           const void* src,
                                                           size_t nbytes) {
  ::memmove(dest, src, nbytes);
}

template <typename T>
inline T js::jit::AtomicOperations::exchangeSeqCst(T* addr, T val) {
  static_assert(sizeof(T) <= sizeof(void*),
                "atomics supported up to pointer size only");
  T v;
  __atomic_exchange(addr, &val, &v, __ATOMIC_SEQ_CST);
  return v;
}

#endif  // jit_mips_shared_AtomicOperations_mips_shared_h