| Index: src/atomicops_internals_arm64_gcc.h | 
| diff --git a/src/atomicops_internals_arm64_gcc.h b/src/atomicops_internals_arm64_gcc.h | 
| index 074da5841ecc5d33d0644f81e7edefa29f533373..e6cac19932ad6858311178b8f83f1ffd4f6bd6be 100644 | 
| --- a/src/atomicops_internals_arm64_gcc.h | 
| +++ b/src/atomicops_internals_arm64_gcc.h | 
| @@ -33,7 +33,13 @@ | 
| namespace v8 { | 
| namespace internal { | 
|  | 
| -inline void MemoryBarrier() { /* Not used. */ } | 
| +inline void MemoryBarrier() { | 
| +  __asm__ __volatile__ (  // NOLINT | 
| +    "dmb ish                                  \n\t"  // Data memory barrier. | 
| +    ::: "memory" | 
| +  );  // NOLINT | 
| +} | 
| + | 
|  | 
| inline Atomic32 NoBarrier_CompareAndSwap(volatile Atomic32* ptr, | 
| Atomic32 old_value, | 
| @@ -43,17 +49,17 @@ inline Atomic32 NoBarrier_CompareAndSwap(volatile Atomic32* ptr, | 
|  | 
| __asm__ __volatile__ (  // NOLINT | 
| "0:                                    \n\t" | 
| -    "ldxr %w[prev], [%[ptr]]               \n\t"  // Load the previous value. | 
| +    "ldxr %w[prev], %[ptr]                 \n\t"  // Load the previous value. | 
| "cmp %w[prev], %w[old_value]           \n\t" | 
| "bne 1f                                \n\t" | 
| -    "stxr %w[temp], %w[new_value], [%[ptr]]\n\t"  // Try to store the new value. | 
| +    "stxr %w[temp], %w[new_value], %[ptr]  \n\t"  // Try to store the new value. | 
| "cbnz %w[temp], 0b                     \n\t"  // Retry if it did not work. | 
| "1:                                    \n\t" | 
| "clrex                                 \n\t"  // In case we didn't swap. | 
| : [prev]"=&r" (prev), | 
| -      [temp]"=&r" (temp) | 
| -    : [ptr]"r" (ptr), | 
| -      [old_value]"r" (old_value), | 
| +      [temp]"=&r" (temp), | 
| +      [ptr]"+Q" (*ptr) | 
| +    : [old_value]"r" (old_value), | 
| [new_value]"r" (new_value) | 
| : "memory", "cc" | 
| );  // NOLINT | 
| @@ -68,13 +74,13 @@ inline Atomic32 NoBarrier_AtomicExchange(volatile Atomic32* ptr, | 
|  | 
| __asm__ __volatile__ (  // NOLINT | 
| "0:                                    \n\t" | 
| -    "ldxr %w[result], [%[ptr]]             \n\t"  // Load the previous value. | 
| -    "stxr %w[temp], %w[new_value], [%[ptr]]\n\t"  // Try to store the new value. | 
| +    "ldxr %w[result], %[ptr]               \n\t"  // Load the previous value. | 
| +    "stxr %w[temp], %w[new_value], %[ptr]  \n\t"  // Try to store the new value. | 
| "cbnz %w[temp], 0b                     \n\t"  // Retry if it did not work. | 
| : [result]"=&r" (result), | 
| -      [temp]"=&r" (temp) | 
| -    : [ptr]"r" (ptr), | 
| -      [new_value]"r" (new_value) | 
| +      [temp]"=&r" (temp), | 
| +      [ptr]"+Q" (*ptr) | 
| +    : [new_value]"r" (new_value) | 
| : "memory" | 
| );  // NOLINT | 
|  | 
| @@ -88,14 +94,14 @@ inline Atomic32 NoBarrier_AtomicIncrement(volatile Atomic32* ptr, | 
|  | 
| __asm__ __volatile__ (  // NOLINT | 
| "0:                                       \n\t" | 
| -    "ldxr %w[result], [%[ptr]]                \n\t"  // Load the previous value. | 
| +    "ldxr %w[result], %[ptr]                  \n\t"  // Load the previous value. | 
| "add %w[result], %w[result], %w[increment]\n\t" | 
| -    "stxr %w[temp], %w[result], [%[ptr]]      \n\t"  // Try to store the result. | 
| +    "stxr %w[temp], %w[result], %[ptr]        \n\t"  // Try to store the result. | 
| "cbnz %w[temp], 0b                        \n\t"  // Retry on failure. | 
| : [result]"=&r" (result), | 
| -      [temp]"=&r" (temp) | 
| -    : [ptr]"r" (ptr), | 
| -      [increment]"r" (increment) | 
| +      [temp]"=&r" (temp), | 
| +      [ptr]"+Q" (*ptr) | 
| +    : [increment]"r" (increment) | 
| : "memory" | 
| );  // NOLINT | 
|  | 
| @@ -104,23 +110,9 @@ inline Atomic32 NoBarrier_AtomicIncrement(volatile Atomic32* ptr, | 
|  | 
| inline Atomic32 Barrier_AtomicIncrement(volatile Atomic32* ptr, | 
| Atomic32 increment) { | 
| -  Atomic32 result; | 
| -  int32_t temp; | 
| - | 
| -  __asm__ __volatile__ (  // NOLINT | 
| -    "dmb ish                                  \n\t"  // Data memory barrier. | 
| -    "0:                                       \n\t" | 
| -    "ldxr %w[result], [%[ptr]]                \n\t"  // Load the previous value. | 
| -    "add %w[result], %w[result], %w[increment]\n\t" | 
| -    "stxr %w[temp], %w[result], [%[ptr]]      \n\t"  // Try to store the result. | 
| -    "cbnz %w[temp], 0b                        \n\t"  // Retry on failure. | 
| -    "dmb ish                                  \n\t"  // Data memory barrier. | 
| -    : [result]"=&r" (result), | 
| -      [temp]"=&r" (temp) | 
| -    : [ptr]"r" (ptr), | 
| -      [increment]"r" (increment) | 
| -    : "memory" | 
| -  );  // NOLINT | 
| +  MemoryBarrier(); | 
| +  Atomic32 result = NoBarrier_AtomicIncrement(ptr, increment); | 
| +  MemoryBarrier(); | 
|  | 
| return result; | 
| } | 
| @@ -133,10 +125,10 @@ inline Atomic32 Acquire_CompareAndSwap(volatile Atomic32* ptr, | 
|  | 
| __asm__ __volatile__ (  // NOLINT | 
| "0:                                    \n\t" | 
| -    "ldxr %w[prev], [%[ptr]]               \n\t"  // Load the previous value. | 
| +    "ldxr %w[prev], %[ptr]                 \n\t"  // Load the previous value. | 
| "cmp %w[prev], %w[old_value]           \n\t" | 
| "bne 1f                                \n\t" | 
| -    "stxr %w[temp], %w[new_value], [%[ptr]]\n\t"  // Try to store the new value. | 
| +    "stxr %w[temp], %w[new_value], %[ptr]  \n\t"  // Try to store the new value. | 
| "cbnz %w[temp], 0b                     \n\t"  // Retry if it did not work. | 
| "dmb ish                               \n\t"  // Data memory barrier. | 
| "1:                                    \n\t" | 
| @@ -144,9 +136,9 @@ inline Atomic32 Acquire_CompareAndSwap(volatile Atomic32* ptr, | 
| // 'clrex'. | 
| "clrex                                 \n\t" | 
| : [prev]"=&r" (prev), | 
| -      [temp]"=&r" (temp) | 
| -    : [ptr]"r" (ptr), | 
| -      [old_value]"r" (old_value), | 
| +      [temp]"=&r" (temp), | 
| +      [ptr]"+Q" (*ptr) | 
| +    : [old_value]"r" (old_value), | 
| [new_value]"r" (new_value) | 
| : "memory", "cc" | 
| );  // NOLINT | 
| @@ -160,21 +152,22 @@ inline Atomic32 Release_CompareAndSwap(volatile Atomic32* ptr, | 
| Atomic32 prev; | 
| int32_t temp; | 
|  | 
| +  MemoryBarrier(); | 
| + | 
| __asm__ __volatile__ (  // NOLINT | 
| -    "dmb ish                               \n\t"  // Data memory barrier. | 
| "0:                                    \n\t" | 
| -    "ldxr %w[prev], [%[ptr]]               \n\t"  // Load the previous value. | 
| +    "ldxr %w[prev], %[ptr]                 \n\t"  // Load the previous value. | 
| "cmp %w[prev], %w[old_value]           \n\t" | 
| "bne 1f                                \n\t" | 
| -    "stxr %w[temp], %w[new_value], [%[ptr]]\n\t"  // Try to store the new value. | 
| +    "stxr %w[temp], %w[new_value], %[ptr]  \n\t"  // Try to store the new value. | 
| "cbnz %w[temp], 0b                     \n\t"  // Retry if it did not work. | 
| "1:                                    \n\t" | 
| // If the compare failed the we still need a 'clrex'. | 
| "clrex                                 \n\t" | 
| : [prev]"=&r" (prev), | 
| -      [temp]"=&r" (temp) | 
| -    : [ptr]"r" (ptr), | 
| -      [old_value]"r" (old_value), | 
| +      [temp]"=&r" (temp), | 
| +      [ptr]"+Q" (*ptr) | 
| +    : [old_value]"r" (old_value), | 
| [new_value]"r" (new_value) | 
| : "memory", "cc" | 
| );  // NOLINT | 
| @@ -188,17 +181,11 @@ inline void NoBarrier_Store(volatile Atomic32* ptr, Atomic32 value) { | 
|  | 
| inline void Acquire_Store(volatile Atomic32* ptr, Atomic32 value) { | 
| *ptr = value; | 
| -  __asm__ __volatile__ (  // NOLINT | 
| -    "dmb ish  \n\t"  // Data memory barrier. | 
| -    ::: "memory"     // Prevent gcc from reordering before the store above. | 
| -  );  // NOLINT | 
| +  MemoryBarrier(); | 
| } | 
|  | 
| inline void Release_Store(volatile Atomic32* ptr, Atomic32 value) { | 
| -  __asm__ __volatile__ (  // NOLINT | 
| -    "dmb ish  \n\t"  // Data memory barrier. | 
| -    ::: "memory"     // Prevent gcc from reordering after the store below. | 
| -  );  // NOLINT | 
| +  MemoryBarrier(); | 
| *ptr = value; | 
| } | 
|  | 
| @@ -208,18 +195,12 @@ inline Atomic32 NoBarrier_Load(volatile const Atomic32* ptr) { | 
|  | 
| inline Atomic32 Acquire_Load(volatile const Atomic32* ptr) { | 
| Atomic32 value = *ptr; | 
| -  __asm__ __volatile__ (  // NOLINT | 
| -    "dmb ish  \n\t"  // Data memory barrier. | 
| -    ::: "memory"     // Prevent gcc from reordering before the load above. | 
| -  );  // NOLINT | 
| +  MemoryBarrier(); | 
| return value; | 
| } | 
|  | 
| inline Atomic32 Release_Load(volatile const Atomic32* ptr) { | 
| -  __asm__ __volatile__ (  // NOLINT | 
| -    "dmb ish  \n\t"  // Data memory barrier. | 
| -    ::: "memory"     // Prevent gcc from reordering after the load below. | 
| -  );  // NOLINT | 
| +  MemoryBarrier(); | 
| return *ptr; | 
| } | 
|  | 
| @@ -234,17 +215,17 @@ inline Atomic64 NoBarrier_CompareAndSwap(volatile Atomic64* ptr, | 
|  | 
| __asm__ __volatile__ (  // NOLINT | 
| "0:                                    \n\t" | 
| -    "ldxr %[prev], [%[ptr]]                \n\t" | 
| +    "ldxr %[prev], %[ptr]                  \n\t" | 
| "cmp %[prev], %[old_value]             \n\t" | 
| "bne 1f                                \n\t" | 
| -    "stxr %w[temp], %[new_value], [%[ptr]] \n\t" | 
| +    "stxr %w[temp], %[new_value], %[ptr]   \n\t" | 
| "cbnz %w[temp], 0b                     \n\t" | 
| "1:                                    \n\t" | 
| "clrex                                 \n\t" | 
| : [prev]"=&r" (prev), | 
| -      [temp]"=&r" (temp) | 
| -    : [ptr]"r" (ptr), | 
| -      [old_value]"r" (old_value), | 
| +      [temp]"=&r" (temp), | 
| +      [ptr]"+Q" (*ptr) | 
| +    : [old_value]"r" (old_value), | 
| [new_value]"r" (new_value) | 
| : "memory", "cc" | 
| );  // NOLINT | 
| @@ -259,13 +240,13 @@ inline Atomic64 NoBarrier_AtomicExchange(volatile Atomic64* ptr, | 
|  | 
| __asm__ __volatile__ (  // NOLINT | 
| "0:                                    \n\t" | 
| -    "ldxr %[result], [%[ptr]]              \n\t" | 
| -    "stxr %w[temp], %[new_value], [%[ptr]] \n\t" | 
| +    "ldxr %[result], %[ptr]                \n\t" | 
| +    "stxr %w[temp], %[new_value], %[ptr]   \n\t" | 
| "cbnz %w[temp], 0b                     \n\t" | 
| : [result]"=&r" (result), | 
| -      [temp]"=&r" (temp) | 
| -    : [ptr]"r" (ptr), | 
| -      [new_value]"r" (new_value) | 
| +      [temp]"=&r" (temp), | 
| +      [ptr]"+Q" (*ptr) | 
| +    : [new_value]"r" (new_value) | 
| : "memory" | 
| );  // NOLINT | 
|  | 
| @@ -279,14 +260,14 @@ inline Atomic64 NoBarrier_AtomicIncrement(volatile Atomic64* ptr, | 
|  | 
| __asm__ __volatile__ (  // NOLINT | 
| "0:                                     \n\t" | 
| -    "ldxr %[result], [%[ptr]]               \n\t" | 
| +    "ldxr %[result], %[ptr]                 \n\t" | 
| "add %[result], %[result], %[increment] \n\t" | 
| -    "stxr %w[temp], %[result], [%[ptr]]     \n\t" | 
| +    "stxr %w[temp], %[result], %[ptr]       \n\t" | 
| "cbnz %w[temp], 0b                      \n\t" | 
| : [result]"=&r" (result), | 
| -      [temp]"=&r" (temp) | 
| -    : [ptr]"r" (ptr), | 
| -      [increment]"r" (increment) | 
| +      [temp]"=&r" (temp), | 
| +      [ptr]"+Q" (*ptr) | 
| +    : [increment]"r" (increment) | 
| : "memory" | 
| );  // NOLINT | 
|  | 
| @@ -295,23 +276,9 @@ inline Atomic64 NoBarrier_AtomicIncrement(volatile Atomic64* ptr, | 
|  | 
| inline Atomic64 Barrier_AtomicIncrement(volatile Atomic64* ptr, | 
| Atomic64 increment) { | 
| -  Atomic64 result; | 
| -  int32_t temp; | 
| - | 
| -  __asm__ __volatile__ (  // NOLINT | 
| -    "dmb ish                                \n\t" | 
| -    "0:                                     \n\t" | 
| -    "ldxr %[result], [%[ptr]]               \n\t" | 
| -    "add %[result], %[result], %[increment] \n\t" | 
| -    "stxr %w[temp], %[result], [%[ptr]]     \n\t" | 
| -    "cbnz %w[temp], 0b                      \n\t" | 
| -    "dmb ish                                \n\t" | 
| -    : [result]"=&r" (result), | 
| -      [temp]"=&r" (temp) | 
| -    : [ptr]"r" (ptr), | 
| -      [increment]"r" (increment) | 
| -    : "memory" | 
| -  );  // NOLINT | 
| +  MemoryBarrier(); | 
| +  Atomic64 result = NoBarrier_AtomicIncrement(ptr, increment); | 
| +  MemoryBarrier(); | 
|  | 
| return result; | 
| } | 
| @@ -324,18 +291,18 @@ inline Atomic64 Acquire_CompareAndSwap(volatile Atomic64* ptr, | 
|  | 
| __asm__ __volatile__ (  // NOLINT | 
| "0:                                    \n\t" | 
| -    "ldxr %[prev], [%[ptr]]                \n\t" | 
| +    "ldxr %[prev], %[ptr]                  \n\t" | 
| "cmp %[prev], %[old_value]             \n\t" | 
| "bne 1f                                \n\t" | 
| -    "stxr %w[temp], %[new_value], [%[ptr]] \n\t" | 
| +    "stxr %w[temp], %[new_value], %[ptr]   \n\t" | 
| "cbnz %w[temp], 0b                     \n\t" | 
| "dmb ish                               \n\t" | 
| "1:                                    \n\t" | 
| "clrex                                 \n\t" | 
| : [prev]"=&r" (prev), | 
| -      [temp]"=&r" (temp) | 
| -    : [ptr]"r" (ptr), | 
| -      [old_value]"r" (old_value), | 
| +      [temp]"=&r" (temp), | 
| +      [ptr]"+Q" (*ptr) | 
| +    : [old_value]"r" (old_value), | 
| [new_value]"r" (new_value) | 
| : "memory", "cc" | 
| );  // NOLINT | 
| @@ -349,20 +316,21 @@ inline Atomic64 Release_CompareAndSwap(volatile Atomic64* ptr, | 
| Atomic64 prev; | 
| int32_t temp; | 
|  | 
| +  MemoryBarrier(); | 
| + | 
| __asm__ __volatile__ (  // NOLINT | 
| -    "dmb ish                               \n\t" | 
| "0:                                    \n\t" | 
| -    "ldxr %[prev], [%[ptr]]                \n\t" | 
| +    "ldxr %[prev], %[ptr]                  \n\t" | 
| "cmp %[prev], %[old_value]             \n\t" | 
| "bne 1f                                \n\t" | 
| -    "stxr %w[temp], %[new_value], [%[ptr]] \n\t" | 
| +    "stxr %w[temp], %[new_value], %[ptr]   \n\t" | 
| "cbnz %w[temp], 0b                     \n\t" | 
| "1:                                    \n\t" | 
| "clrex                                 \n\t" | 
| : [prev]"=&r" (prev), | 
| -      [temp]"=&r" (temp) | 
| -    : [ptr]"r" (ptr), | 
| -      [old_value]"r" (old_value), | 
| +      [temp]"=&r" (temp), | 
| +      [ptr]"+Q" (*ptr) | 
| +    : [old_value]"r" (old_value), | 
| [new_value]"r" (new_value) | 
| : "memory", "cc" | 
| );  // NOLINT | 
| @@ -376,17 +344,11 @@ inline void NoBarrier_Store(volatile Atomic64* ptr, Atomic64 value) { | 
|  | 
| inline void Acquire_Store(volatile Atomic64* ptr, Atomic64 value) { | 
| *ptr = value; | 
| -  __asm__ __volatile__ (  // NOLINT | 
| -    "dmb ish  \n\t" | 
| -    ::: "memory" | 
| -  );  // NOLINT | 
| +  MemoryBarrier(); | 
| } | 
|  | 
| inline void Release_Store(volatile Atomic64* ptr, Atomic64 value) { | 
| -  __asm__ __volatile__ (  // NOLINT | 
| -    "dmb ish  \n\t" | 
| -    ::: "memory" | 
| -  );  // NOLINT | 
| +  MemoryBarrier(); | 
| *ptr = value; | 
| } | 
|  | 
| @@ -396,18 +358,12 @@ inline Atomic64 NoBarrier_Load(volatile const Atomic64* ptr) { | 
|  | 
| inline Atomic64 Acquire_Load(volatile const Atomic64* ptr) { | 
| Atomic64 value = *ptr; | 
| -  __asm__ __volatile__ (  // NOLINT | 
| -    "dmb ish  \n\t" | 
| -    ::: "memory" | 
| -  );  // NOLINT | 
| +  MemoryBarrier(); | 
| return value; | 
| } | 
|  | 
| inline Atomic64 Release_Load(volatile const Atomic64* ptr) { | 
| -  __asm__ __volatile__ (  // NOLINT | 
| -    "dmb ish  \n\t" | 
| -    ::: "memory" | 
| -  );  // NOLINT | 
| +  MemoryBarrier(); | 
| return *ptr; | 
| } | 
|  | 
|  |