Merge experimental/a64 to bleeding_edge.

src/atomicops_internals_a64_gcc.h

Index: src/atomicops_internals_a64_gcc.h
diff --git a/src/atomicops_internals_a64_gcc.h b/src/atomicops_internals_a64_gcc.h
new file mode 100644
index 0000000000000000000000000000000000000000..074da5841ecc5d33d0644f81e7edefa29f533373
--- /dev/null
+++ b/src/atomicops_internals_a64_gcc.h
@@ -0,0 +1,416 @@
+// Copyright 2012 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// This file is an internal atomic implementation, use atomicops.h instead.
+
+#ifndef V8_ATOMICOPS_INTERNALS_ARM_GCC_H_
+#define V8_ATOMICOPS_INTERNALS_ARM_GCC_H_
+
+namespace v8 {
+namespace internal {
+
+inline void MemoryBarrier() { /* Not used. */ }
+
+inline Atomic32 NoBarrier_CompareAndSwap(volatile Atomic32* ptr,
+                                         Atomic32 old_value,
+                                         Atomic32 new_value) {
+  Atomic32 prev;
+  int32_t temp;
+
+  __asm__ __volatile__ (  // NOLINT
+    "0:                                    \n\t"
+    "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.
+    "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),
+      [new_value]"r" (new_value)
+    : "memory", "cc"
+  );  // NOLINT
+
+  return prev;
+}
+
+inline Atomic32 NoBarrier_AtomicExchange(volatile Atomic32* ptr,
+                                         Atomic32 new_value) {
+  Atomic32 result;
+  int32_t temp;
+
+  __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.
+    "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)
+    : "memory"
+  );  // NOLINT
+
+  return result;
+}
+
+inline Atomic32 NoBarrier_AtomicIncrement(volatile Atomic32* ptr,
+                                          Atomic32 increment) {
+  Atomic32 result;
+  int32_t temp;
+
+  __asm__ __volatile__ (  // NOLINT
+    "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.
+    : [result]"=&r" (result),
+      [temp]"=&r" (temp)
+    : [ptr]"r" (ptr),
+      [increment]"r" (increment)
+    : "memory"
+  );  // NOLINT
+
+  return result;
+}
+
+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
+
+  return result;
+}
+
+inline Atomic32 Acquire_CompareAndSwap(volatile Atomic32* ptr,
+                                       Atomic32 old_value,
+                                       Atomic32 new_value) {
+  Atomic32 prev;
+  int32_t temp;
+
+  __asm__ __volatile__ (  // NOLINT
+    "0:                                    \n\t"
+    "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.
+    "cbnz %w[temp], 0b                     \n\t"  // Retry if it did not work.
+    "dmb ish                               \n\t"  // Data memory barrier.
+    "1:                                    \n\t"
+    // If the compare failed the 'dmb' is unnecessary, but we still need a
+    // 'clrex'.
+    "clrex                                 \n\t"
+    : [prev]"=&r" (prev),
+      [temp]"=&r" (temp)
+    : [ptr]"r" (ptr),
+      [old_value]"r" (old_value),
+      [new_value]"r" (new_value)
+    : "memory", "cc"
+  );  // NOLINT
+
+  return prev;
+}
+
+inline Atomic32 Release_CompareAndSwap(volatile Atomic32* ptr,
+                                       Atomic32 old_value,
+                                       Atomic32 new_value) {
+  Atomic32 prev;
+  int32_t temp;
+
+  __asm__ __volatile__ (  // NOLINT
+    "dmb ish                               \n\t"  // Data memory barrier.
+    "0:                                    \n\t"
+    "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.
+    "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),
+      [new_value]"r" (new_value)
+    : "memory", "cc"
+  );  // NOLINT
+
+  return prev;
+}
+
+inline void NoBarrier_Store(volatile Atomic32* ptr, Atomic32 value) {
+  *ptr = 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
+}
+
+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
+  *ptr = value;
+}
+
+inline Atomic32 NoBarrier_Load(volatile const Atomic32* ptr) {
+  return *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
+  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
+  return *ptr;
+}
+
+// 64-bit versions of the operations.
+// See the 32-bit versions for comments.
+
+inline Atomic64 NoBarrier_CompareAndSwap(volatile Atomic64* ptr,
+                                         Atomic64 old_value,
+                                         Atomic64 new_value) {
+  Atomic64 prev;
+  int32_t temp;
+
+  __asm__ __volatile__ (  // NOLINT
+    "0:                                    \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"
+    "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),
+      [new_value]"r" (new_value)
+    : "memory", "cc"
+  );  // NOLINT
+
+  return prev;
+}
+
+inline Atomic64 NoBarrier_AtomicExchange(volatile Atomic64* ptr,
+                                         Atomic64 new_value) {
+  Atomic64 result;
+  int32_t temp;
+
+  __asm__ __volatile__ (  // NOLINT
+    "0:                                    \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)
+    : "memory"
+  );  // NOLINT
+
+  return result;
+}
+
+inline Atomic64 NoBarrier_AtomicIncrement(volatile Atomic64* ptr,
+                                          Atomic64 increment) {
+  Atomic64 result;
+  int32_t temp;
+
+  __asm__ __volatile__ (  // NOLINT
+    "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"
+    : [result]"=&r" (result),
+      [temp]"=&r" (temp)
+    : [ptr]"r" (ptr),
+      [increment]"r" (increment)
+    : "memory"
+  );  // NOLINT
+
+  return result;
+}
+
+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
+
+  return result;
+}
+
+inline Atomic64 Acquire_CompareAndSwap(volatile Atomic64* ptr,
+                                       Atomic64 old_value,
+                                       Atomic64 new_value) {
+  Atomic64 prev;
+  int32_t temp;
+
+  __asm__ __volatile__ (  // NOLINT
+    "0:                                    \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"
+    "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),
+      [new_value]"r" (new_value)
+    : "memory", "cc"
+  );  // NOLINT
+
+  return prev;
+}
+
+inline Atomic64 Release_CompareAndSwap(volatile Atomic64* ptr,
+                                       Atomic64 old_value,
+                                       Atomic64 new_value) {
+  Atomic64 prev;
+  int32_t temp;
+
+  __asm__ __volatile__ (  // NOLINT
+    "dmb ish                               \n\t"
+    "0:                                    \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"
+    "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),
+      [new_value]"r" (new_value)
+    : "memory", "cc"
+  );  // NOLINT
+
+  return prev;
+}
+
+inline void NoBarrier_Store(volatile Atomic64* ptr, Atomic64 value) {
+  *ptr = value;
+}
+
+inline void Acquire_Store(volatile Atomic64* ptr, Atomic64 value) {
+  *ptr = value;
+  __asm__ __volatile__ (  // NOLINT
+    "dmb ish  \n\t"
+    ::: "memory"
+  );  // NOLINT
+}
+
+inline void Release_Store(volatile Atomic64* ptr, Atomic64 value) {
+  __asm__ __volatile__ (  // NOLINT
+    "dmb ish  \n\t"
+    ::: "memory"
+  );  // NOLINT
+  *ptr = value;
+}
+
+inline Atomic64 NoBarrier_Load(volatile const Atomic64* ptr) {
+  return *ptr;
+}
+
+inline Atomic64 Acquire_Load(volatile const Atomic64* ptr) {
+  Atomic64 value = *ptr;
+  __asm__ __volatile__ (  // NOLINT
+    "dmb ish  \n\t"
+    ::: "memory"
+  );  // NOLINT
+  return value;
+}
+
+inline Atomic64 Release_Load(volatile const Atomic64* ptr) {
+  __asm__ __volatile__ (  // NOLINT
+    "dmb ish  \n\t"
+    ::: "memory"
+  );  // NOLINT
+  return *ptr;
+}
+
+} }  // namespace v8::internal
+
+#endif  // V8_ATOMICOPS_INTERNALS_ARM_GCC_H_