[Atomics] Rename Atomics.futex*, remove Atomics.futexWakeOrRequeue

* Rename Atomics.futexWait -> Atomics.wait
* Rename Atomics.futexWake -> Atomics.wake
* Remove Atomics.futexWakeOrRequeue
* Return value of Atomics.wait is now a string: "ok", "not-equal" or
  "timed-out"
* Update comments that reference URL for ecmascript_sharedmem to
  https://github.com/tc39/ecmascript_sharedmem

Review-Url: https://codereview.chromium.org/2143443002
Cr-Commit-Position: refs/heads/master@{#37727}

src/futex-emulation.cc

@@ -84,7 +84,7 @@ Object* FutexEmulation::Wait(Isolate* isolate,
   base::LockGuard<base::Mutex> lock_guard(mutex_.Pointer());
 
   if (*p != value) {
-    return Smi::FromInt(Result::kNotEqual);
+    return isolate->heap()->not_equal();
   }
 
   FutexWaitListNode* node = isolate->futex_wait_list_node();
@@ -157,7 +157,7 @@ Object* FutexEmulation::Wait(Isolate* isolate,
     }
 
     if (!node->waiting_) {
-      result = Smi::FromInt(Result::kOk);
+      result = isolate->heap()->ok();
       break;
     }
 
@@ -165,7 +165,7 @@ Object* FutexEmulation::Wait(Isolate* isolate,
     if (use_timeout) {
       current_time = base::TimeTicks::Now();
       if (current_time >= timeout_time) {
-        result = Smi::FromInt(Result::kTimedOut);
+        result = isolate->heap()->timed_out();
         break;
       }
 
@@ -213,44 +213,6 @@ Object* FutexEmulation::Wake(Isolate* isolate,
 }
 
 
-Object* FutexEmulation::WakeOrRequeue(Isolate* isolate,
-                                      Handle<JSArrayBuffer> array_buffer,
-                                      size_t addr, int num_waiters_to_wake,
-                                      int32_t value, size_t addr2) {
-  DCHECK(addr < NumberToSize(isolate, array_buffer->byte_length()));
-  DCHECK(addr2 < NumberToSize(isolate, array_buffer->byte_length()));
-
-  void* backing_store = array_buffer->backing_store();
-  int32_t* p =
-      reinterpret_cast<int32_t*>(static_cast<int8_t*>(backing_store) + addr);
-
-  base::LockGuard<base::Mutex> lock_guard(mutex_.Pointer());
-  if (*p != value) {
-    return Smi::FromInt(Result::kNotEqual);
-  }
-
-  // Wake |num_waiters_to_wake|
-  int waiters_woken = 0;
-  FutexWaitListNode* node = wait_list_.Pointer()->head_;
-  while (node) {
-    if (backing_store == node->backing_store_ && addr == node->wait_addr_) {
-      if (num_waiters_to_wake > 0) {
-        node->waiting_ = false;
-        node->cond_.NotifyOne();
-        --num_waiters_to_wake;
-        waiters_woken++;
-      } else {
-        node->wait_addr_ = addr2;
-      }
-    }
-
-    node = node->next_;
-  }
-
-  return Smi::FromInt(waiters_woken);
-}
-
-
 Object* FutexEmulation::NumWaitersForTesting(Isolate* isolate,
                                              Handle<JSArrayBuffer> array_buffer,
                                              size_t addr) {

src/futex-emulation.h

@@ -21,7 +21,7 @@
 // variables for consistency.
 //
 // This is used by the Futex API defined in the SharedArrayBuffer draft spec,
-// found here: https://github.com/lars-t-hansen/ecmascript_sharedmem
+// found here: https://github.com/tc39/ecmascript_sharedmem
 
 namespace v8 {
 
@@ -81,18 +81,11 @@ class FutexWaitList {
 
 class FutexEmulation : public AllStatic {
  public:
-  // These must match the values in src/harmony-atomics.js
-  enum Result {
-    kOk = 0,
-    kNotEqual = -1,
-    kTimedOut = -2,
-  };
-
-  // Check that array_buffer[addr] == value, and return kNotEqual if not. If
+  // Check that array_buffer[addr] == value, and return "not-equal" if not. If
   // they are equal, block execution on |isolate|'s thread until woken via
   // |Wake|, or when the time given in |rel_timeout_ms| elapses. Note that
   // |rel_timeout_ms| can be Infinity.
-  // If woken, return kOk, otherwise return kTimedOut. The initial check and
+  // If woken, return "ok", otherwise return "timed-out". The initial check and
   // the decision to wait happen atomically.
   static Object* Wait(Isolate* isolate, Handle<JSArrayBuffer> array_buffer,
                       size_t addr, int32_t value, double rel_timeout_ms);
@@ -103,16 +96,6 @@ class FutexEmulation : public AllStatic {
   static Object* Wake(Isolate* isolate, Handle<JSArrayBuffer> array_buffer,
                       size_t addr, int num_waiters_to_wake);
 
-  // Check that array_buffer[addr] == value, and return kNotEqual if not. If
-  // they are equal, wake |num_waiters_to_wake| threads that are waiting on the
-  // given |addr|. The rest of the waiters will continue to wait, but will now
-  // be waiting on |addr2| instead of |addr|. The return value is the number of
-  // woken waiters or kNotEqual as described above.
-  static Object* WakeOrRequeue(Isolate* isolate,
-                               Handle<JSArrayBuffer> array_buffer, size_t addr,
-                               int num_waiters_to_wake, int32_t value,
-                               size_t addr2);
-
   // Return the number of threads waiting on |addr|. Should only be used for
   // testing.
   static Object* NumWaitersForTesting(Isolate* isolate,

src/heap-symbols.h

@@ -97,12 +97,14 @@
   V(name_string, "name")                                           \
   V(nan_string, "NaN")                                             \
   V(next_string, "next")                                           \
+  V(not_equal, "not-equal")                                        \
   V(null_string, "null")                                           \
   V(null_to_string, "[object Null]")                               \
   V(number_string, "number")                                       \
   V(Number_string, "Number")                                       \
   V(object_string, "object")                                       \
   V(Object_string, "Object")                                       \
+  V(ok, "ok")                                                      \
   V(ownKeys_string, "ownKeys")                                     \
   V(position_string, "position")                                   \
   V(preventExtensions_string, "preventExtensions")                 \
@@ -129,6 +131,7 @@
   V(Symbol_string, "Symbol")                                       \
   V(this_string, "this")                                           \
   V(throw_string, "throw")                                         \
+  V(timed_out, "timed-out")                                        \
   V(toJSON_string, "toJSON")                                       \
   V(toString_string, "toString")                                   \
   V(true_string, "true")                                           \

src/js/harmony-atomics.js

@@ -108,9 +108,7 @@ function AtomicsIsLockFreeJS(size) {
   return %_AtomicsIsLockFree(size);
 }
 
-// Futexes
-
-function AtomicsFutexWaitJS(ia, index, value, timeout) {
+function AtomicsWaitJS(ia, index, value, timeout) {
   CheckSharedInteger32TypedArray(ia);
   index = ValidateIndex(index, %_TypedArrayGetLength(ia));
   if (IS_UNDEFINED(timeout)) {
@@ -123,27 +121,14 @@ function AtomicsFutexWaitJS(ia, index, value, timeout) {
       timeout = MaxSimple(0, timeout);
     }
   }
-  return %AtomicsFutexWait(ia, index, value, timeout);
+  return %AtomicsWait(ia, index, value, timeout);
 }
 
-function AtomicsFutexWakeJS(ia, index, count) {
+function AtomicsWakeJS(ia, index, count) {
   CheckSharedInteger32TypedArray(ia);
   index = ValidateIndex(index, %_TypedArrayGetLength(ia));
   count = MaxSimple(0, TO_INTEGER(count));
-  return %AtomicsFutexWake(ia, index, count);
-}
-
-function AtomicsFutexWakeOrRequeueJS(ia, index1, count, value, index2) {
-  CheckSharedInteger32TypedArray(ia);
-  index1 = ValidateIndex(index1, %_TypedArrayGetLength(ia));
-  count = MaxSimple(0, TO_INTEGER(count));
-  value = TO_INT32(value);
-  index2 = ValidateIndex(index2, %_TypedArrayGetLength(ia));
-  if (index1 < 0 || index1 >= %_TypedArrayGetLength(ia) ||
-      index2 < 0 || index2 >= %_TypedArrayGetLength(ia)) {
-    return UNDEFINED;
-  }
-  return %AtomicsFutexWakeOrRequeue(ia, index1, count, value, index2);
+  return %AtomicsWake(ia, index, count);
 }
 
 // -------------------------------------------------------------------
@@ -154,13 +139,6 @@ var Atomics = global.Atomics;
 
 %AddNamedProperty(Atomics, toStringTagSymbol, "Atomics", READ_ONLY | DONT_ENUM);
 
-// These must match the values in src/futex-emulation.h
-utils.InstallConstants(Atomics, [
-  "OK", 0,
-  "NOTEQUAL", -1,
-  "TIMEDOUT", -2,
-]);
-
 utils.InstallFunctions(Atomics, DONT_ENUM, [
   // TODO(binji): remove the rest of the (non futex) Atomics functions as they
   // become builtins.
@@ -172,9 +150,8 @@ utils.InstallFunctions(Atomics, DONT_ENUM, [
   "xor", AtomicsXorJS,
   "exchange", AtomicsExchangeJS,
   "isLockFree", AtomicsIsLockFreeJS,
-  "futexWait", AtomicsFutexWaitJS,
-  "futexWake", AtomicsFutexWakeJS,
-  "futexWakeOrRequeue", AtomicsFutexWakeOrRequeueJS,
+  "wait", AtomicsWaitJS,
+  "wake", AtomicsWakeJS,
 ]);
 
 })

src/runtime/runtime-atomics.cc

@@ -12,7 +12,7 @@
 
 // Implement Atomic accesses to SharedArrayBuffers as defined in the
 // SharedArrayBuffer draft spec, found here
-// https://github.com/lars-t-hansen/ecmascript_sharedmem
+// https://github.com/tc39/ecmascript_sharedmem
 
 namespace v8 {
 namespace internal {

src/runtime/runtime-futex.cc

@@ -12,12 +12,12 @@
 
 // Implement Futex API for SharedArrayBuffers as defined in the
 // SharedArrayBuffer draft spec, found here:
-// https://github.com/lars-t-hansen/ecmascript_sharedmem
+// https://github.com/tc39/ecmascript_sharedmem
 
 namespace v8 {
 namespace internal {
 
-RUNTIME_FUNCTION(Runtime_AtomicsFutexWait) {
+RUNTIME_FUNCTION(Runtime_AtomicsWait) {
   HandleScope scope(isolate);
   DCHECK(args.length() == 4);
   CONVERT_ARG_HANDLE_CHECKED(JSTypedArray, sta, 0);
@@ -35,8 +35,7 @@ RUNTIME_FUNCTION(Runtime_AtomicsFutexWait) {
   return FutexEmulation::Wait(isolate, array_buffer, addr, value, timeout);
 }
 
-
-RUNTIME_FUNCTION(Runtime_AtomicsFutexWake) {
+RUNTIME_FUNCTION(Runtime_AtomicsWake) {
   HandleScope scope(isolate);
   DCHECK(args.length() == 3);
   CONVERT_ARG_HANDLE_CHECKED(JSTypedArray, sta, 0);
@@ -52,30 +51,7 @@ RUNTIME_FUNCTION(Runtime_AtomicsFutexWake) {
   return FutexEmulation::Wake(isolate, array_buffer, addr, count);
 }
 
-
-RUNTIME_FUNCTION(Runtime_AtomicsFutexWakeOrRequeue) {
-  HandleScope scope(isolate);
-  DCHECK(args.length() == 5);
-  CONVERT_ARG_HANDLE_CHECKED(JSTypedArray, sta, 0);
-  CONVERT_SIZE_ARG_CHECKED(index1, 1);
-  CONVERT_INT32_ARG_CHECKED(count, 2);
-  CONVERT_INT32_ARG_CHECKED(value, 3);
-  CONVERT_SIZE_ARG_CHECKED(index2, 4);
-  CHECK(sta->GetBuffer()->is_shared());
-  CHECK_LT(index1, NumberToSize(isolate, sta->length()));
-  CHECK_LT(index2, NumberToSize(isolate, sta->length()));
-  CHECK_EQ(sta->type(), kExternalInt32Array);
-
-  Handle<JSArrayBuffer> array_buffer = sta->GetBuffer();
-  size_t addr1 = (index1 << 2) + NumberToSize(isolate, sta->byte_offset());
-  size_t addr2 = (index2 << 2) + NumberToSize(isolate, sta->byte_offset());
-
-  return FutexEmulation::WakeOrRequeue(isolate, array_buffer, addr1, count,
-                                       value, addr2);
-}
-
-
-RUNTIME_FUNCTION(Runtime_AtomicsFutexNumWaitersForTesting) {
+RUNTIME_FUNCTION(Runtime_AtomicsNumWaitersForTesting) {
   HandleScope scope(isolate);
   DCHECK(args.length() == 2);
   CONVERT_ARG_HANDLE_CHECKED(JSTypedArray, sta, 0);

src/runtime/runtime.h

@@ -64,13 +64,10 @@ namespace internal {
   F(AtomicsOr, 3, 1)                            \
   F(AtomicsXor, 3, 1)                           \
   F(AtomicsExchange, 3, 1)                      \
-  F(AtomicsIsLockFree, 1, 1)
-
-#define FOR_EACH_INTRINSIC_FUTEX(F)  \
-  F(AtomicsFutexWait, 4, 1)          \
-  F(AtomicsFutexWake, 3, 1)          \
-  F(AtomicsFutexWakeOrRequeue, 5, 1) \
-  F(AtomicsFutexNumWaitersForTesting, 2, 1)
+  F(AtomicsIsLockFree, 1, 1)                    \
+  F(AtomicsWait, 4, 1)                          \
+  F(AtomicsWake, 3, 1)                          \
+  F(AtomicsNumWaitersForTesting, 2, 1)
 
 #define FOR_EACH_INTRINSIC_CLASSES(F)       \
   F(ThrowNonMethodError, 0, 1)              \
@@ -966,7 +963,6 @@ namespace internal {
   FOR_EACH_INTRINSIC_FORIN(F)               \
   FOR_EACH_INTRINSIC_INTERPRETER(F)         \
   FOR_EACH_INTRINSIC_FUNCTION(F)            \
-  FOR_EACH_INTRINSIC_FUTEX(F)               \
   FOR_EACH_INTRINSIC_GENERATOR(F)           \
   FOR_EACH_INTRINSIC_I18N(F)                \
   FOR_EACH_INTRINSIC_INTERNAL(F)            \

test/cctest/test-api.cc

@@ -25043,7 +25043,7 @@ TEST(FutexInterruption) {
   CompileRun(
       "var ab = new SharedArrayBuffer(4);"
       "var i32a = new Int32Array(ab);"
-      "Atomics.futexWait(i32a, 0, 0);");
+      "Atomics.wait(i32a, 0, 0);");
   CHECK(try_catch.HasTerminated());
   timeout_thread.Join();
 }