Implement Atomics API

test/mjsunit/harmony/atomics.js

+// Copyright 2014 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --harmony-atomics --harmony-sharedarraybuffer
+//
+
+var IntegerTypedArrayConstructors = [
+  {constr: Int8Array, min: -128, max: 127},
+  {constr: Int16Array, min: -32768, max: 32767},
+  {constr: Int32Array, min: -0x80000000, max: 0x7fffffff},
+  {constr: Uint8Array, min: 0, max: 255},
+// TODO(binji): support?
+//  {constr: Uint8ClampedArray, min: 0, max: 255},

[Jarin, 2015/06/01 17:50:10]

The spec has the clamped arrays, so I guess we should support them.

[binji, 2015/06/02 21:32:55]

JF suggested we should push back on this. I agree, as it makes the code more
complex and it is not clear yet what the benefit is.

[Jarin, 2015/06/03 13:30:15]

Acknowledged.

+  {constr: Uint16Array, min: 0, max: 65535},
+  {constr: Uint32Array, min: 0, max: 0xffffffff},
+];
+
+var TypedArrayConstructors = IntegerTypedArrayConstructors.concat([
+  {constr: Float32Array},
+  {constr: Float64Array},
+]);
+
+(function TestBadArray() {
+  var ab = new ArrayBuffer(16);
+  var u32a = new Uint32Array(16);
+  var sab = new SharedArrayBuffer(128);
+  var sf32a = new Float32Array(sab);
+  var sf64a = new Float64Array(sab);
+
+  // Atomic ops required shared typed arrays
+  [undefined, 1, 'hi', 3.4, ab, u32a, sab].forEach(function(o) {
+    assertThrows(function() { Atomics.compareExchange(o, 0, 0, 0); },
+                 TypeError);
+    assertThrows(function() { Atomics.load(o, 0); }, TypeError);
+    assertThrows(function() { Atomics.store(o, 0, 0); }, TypeError);
+    assertThrows(function() { Atomics.add(o, 0, 0); }, TypeError);
+    assertThrows(function() { Atomics.sub(o, 0, 0); }, TypeError);
+    assertThrows(function() { Atomics.and(o, 0, 0); }, TypeError);
+    assertThrows(function() { Atomics.or(o, 0, 0); }, TypeError);
+    assertThrows(function() { Atomics.xor(o, 0, 0); }, TypeError);
+    assertThrows(function() { Atomics.exchange(o, 0, 0); }, TypeError);
+  });
+
+  // Arithmetic atomic ops require integer shared arrays
+  [sab, sf32a, sf64a].forEach(function(o) {
+    assertThrows(function() { Atomics.add(o, 0, 0); }, TypeError);
+    assertThrows(function() { Atomics.sub(o, 0, 0); }, TypeError);
+    assertThrows(function() { Atomics.and(o, 0, 0); }, TypeError);
+    assertThrows(function() { Atomics.or(o, 0, 0); }, TypeError);
+    assertThrows(function() { Atomics.xor(o, 0, 0); }, TypeError);
+    assertThrows(function() { Atomics.exchange(o, 0, 0); }, TypeError);
+  });
+})();
+
+function testAtomicOp(op, ia, index, expectedIndex, name) {
+  for (var i = 0; i < ia.length; ++i)
+    ia[i] = 22;
+
+  ia[expectedIndex] = 0;
+  assertEquals(0, op(ia, index, 0, 0), name);
+  assertEquals(0, ia[expectedIndex], name);
+
+  for (var i = 0; i < ia.length; ++i) {
+    if (i == expectedIndex) continue;
+    assertEquals(22, ia[i], name);
+  }
+}
+
+(function TestBadIndex() {
+  var sab = new SharedArrayBuffer(8);
+  var si32a = new Int32Array(sab);
+
+  // Non-integer indexes are converted to an integer first, so they should all
+  // operate on index 0.
+  [undefined, null, false, 'hi', {}].forEach(function(i) {
+    var name = String(i);
+
+    testAtomicOp(Atomics.compareExchange, si32a, i, 0, name);
+    testAtomicOp(Atomics.load, si32a, i, 0, name);
+    testAtomicOp(Atomics.store, si32a, i, 0, name);
+    testAtomicOp(Atomics.add, si32a, i, 0, name);
+    testAtomicOp(Atomics.sub, si32a, i, 0, name);
+    testAtomicOp(Atomics.and, si32a, i, 0, name);
+    testAtomicOp(Atomics.or, si32a, i, 0, name);
+    testAtomicOp(Atomics.xor, si32a, i, 0, name);
+    testAtomicOp(Atomics.exchange, si32a, i, 0, name);
+  });
+
+  // Out-of-bounds indexes should return undefined.
+  // TODO(binji): Should these throw RangeError instead?
+  [-1, 2, 100].forEach(function(i) {
+    var name = String(i);
+    assertEquals(undefined, Atomics.compareExchange(si32a, i, 0, 0), name);
+    assertEquals(undefined, Atomics.load(si32a, i), name);
+    assertEquals(undefined, Atomics.store(si32a, i, 0), name);
+    assertEquals(undefined, Atomics.add(si32a, i, 0), name);
+    assertEquals(undefined, Atomics.sub(si32a, i, 0), name);
+    assertEquals(undefined, Atomics.and(si32a, i, 0), name);
+    assertEquals(undefined, Atomics.or(si32a, i, 0), name);
+    assertEquals(undefined, Atomics.xor(si32a, i, 0), name);
+    assertEquals(undefined, Atomics.exchange(si32a, i, 0), name);
+  });
+})();
+
+(function TestGoodIndex() {
+  var sab = new SharedArrayBuffer(64);
+  var si32a = new Int32Array(sab);
+
+  var valueOf = {valueOf: function(){ return 3;}};
+  var toString = {toString: function(){ return '3';}};
+
+  [3, 3.5, '3', '3.5', valueOf, toString].forEach(function(i) {
+    var name = String(i);
+
+    testAtomicOp(Atomics.compareExchange, si32a, i, 3, name);
+    testAtomicOp(Atomics.load, si32a, i, 3, name);
+    testAtomicOp(Atomics.store, si32a, i, 3, name);
+    testAtomicOp(Atomics.add, si32a, i, 3, name);
+    testAtomicOp(Atomics.sub, si32a, i, 3, name);
+    testAtomicOp(Atomics.and, si32a, i, 3, name);
+    testAtomicOp(Atomics.or, si32a, i, 3, name);
+    testAtomicOp(Atomics.xor, si32a, i, 3, name);
+    testAtomicOp(Atomics.exchange, si32a, i, 3, name);
+  });
+})();
+
+(function TestCompareExchange() {
+  TypedArrayConstructors.forEach(function(t) {
+    var sab = new SharedArrayBuffer(10 * t.constr.BYTES_PER_ELEMENT);
+    var sta = new t.constr(sab);
+    var name = Object.prototype.toString.call(sta);
+    for (var i = 0; i < 10; ++i) {
+      // sta[i] == 0, CAS will store
+      assertEquals(0, Atomics.compareExchange(sta, i, 0, 50), name);
+      assertEquals(50, sta[i], name);
+
+      // sta[i] == 50, CAS will not store
+      assertEquals(50, Atomics.compareExchange(sta, i, 0, 100), name);
+      assertEquals(50, sta[i], name);
+    }
+  });
+
+  IntegerTypedArrayConstructors.forEach(function(t) {
+    var sab = new SharedArrayBuffer(10 * t.constr.BYTES_PER_ELEMENT);
+    var sta = new t.constr(sab);
+    var name = Object.prototype.toString.call(sta);
+    var range = t.max - t.min + 1;
+    var add;
+    var oldVal, oldValWrapped;
+    var newVal, newValWrapped;
+
+    for (add = -range; add <= range; add += range) {
+      sta[0] = oldVal = 0;
+      newVal = t.max + add + 1;
+      newValWrapped = t.min;
+      assertEquals(oldVal,
+                   Atomics.compareExchange(sta, 0, oldVal, newVal), name);
+      assertEquals(newValWrapped, sta[0], name);
+
+      oldVal = newVal;
+      oldValWrapped = newValWrapped;
+      newVal = t.min + add - 1;
+      newValWrapped = t.max;
+      assertEquals(oldValWrapped,
+                   Atomics.compareExchange(sta, 0, oldVal, newVal), name);
+      assertEquals(newValWrapped, sta[0], name);
+    }
+  });
+
+  // * Exact float values should be OK
+  // * Infinity, -Infinity should be OK (has exact representation)
+  // * NaN is not OK, it has many representations, cannot ensure successful CAS
+  // because it does a bitwise compare
+  [1.5, 4.25, -1e8, -Infinity, Infinity].forEach(function(v) {
+    var sab = new SharedArrayBuffer(10 * Float32Array.BYTES_PER_ELEMENT);
+    var sf32a = new Float32Array(sab);
+    sf32a[0] = 0;
+    assertEquals(0, Atomics.compareExchange(sf32a, 0, 0, v));
+    assertEquals(v, sf32a[0]);
+    assertEquals(v, Atomics.compareExchange(sf32a, 0, v, 0));
+    assertEquals(0, sf32a[0]);
+
+    var sab2 = new SharedArrayBuffer(10 * Float64Array.BYTES_PER_ELEMENT);
+    var sf64a = new Float64Array(sab2);
+    sf64a[0] = 0;
+    assertEquals(0, Atomics.compareExchange(sf64a, 0, 0, v));
+    assertEquals(v, sf64a[0]);
+    assertEquals(v, Atomics.compareExchange(sf64a, 0, v, 0));
+    assertEquals(0, sf64a[0]);
+  });
+})();
+
+(function TestLoad() {
+  TypedArrayConstructors.forEach(function(t) {
+    var sab = new SharedArrayBuffer(10 * t.constr.BYTES_PER_ELEMENT);
+    var sta = new t.constr(sab);
+    var name = Object.prototype.toString.call(sta);
+    for (var i = 0; i < 10; ++i) {
+      sta[i] = 0;
+      assertEquals(0, Atomics.load(sta, i), name);
+      sta[i] = 50;
+      assertEquals(50, Atomics.load(sta, i), name);
+    }
+  });
+})();
+
+(function TestStore() {
+  TypedArrayConstructors.forEach(function(t) {
+    var sab = new SharedArrayBuffer(10 * t.constr.BYTES_PER_ELEMENT);
+    var sta = new t.constr(sab);
+    var name = Object.prototype.toString.call(sta);
+    for (var i = 0; i < 10; ++i) {
+      assertEquals(50, Atomics.store(sta, i, 50), name);
+      assertEquals(50, sta[i], name);
+
+      assertEquals(100, Atomics.store(sta, i, 100), name);
+      assertEquals(100, sta[i], name);
+    }
+  });
+
+  IntegerTypedArrayConstructors.forEach(function(t) {
+    var sab = new SharedArrayBuffer(10 * t.constr.BYTES_PER_ELEMENT);
+    var sta = new t.constr(sab);
+    var name = Object.prototype.toString.call(sta);
+    var range = t.max - t.min + 1;
+    var add;
+    var val, valWrapped;
+
+    for (add = -range; add <= range; add += range) {
+      sta[0] = 0;
+      val = t.max + add + 1;
+      valWrapped = t.min;
+      assertEquals(val, Atomics.store(sta, 0, val), name);
+      assertEquals(valWrapped, sta[0], name);
+
+      val = t.min + add - 1;
+      valWrapped = t.max;
+      assertEquals(val, Atomics.store(sta, 0, val), name);
+      assertEquals(valWrapped, sta[0], name);
+    }
+  });
+
+  [1.5, 4.25, -1e8, -Infinity, Infinity, NaN].forEach(function(v) {
+    var sab = new SharedArrayBuffer(10 * Float32Array.BYTES_PER_ELEMENT);
+    var sf32a = new Float32Array(sab);
+    sf32a[0] = 0;
+    assertEquals(v, Atomics.store(sf32a, 0, v));
+    assertEquals(v, sf32a[0]);
+
+    var sab2 = new SharedArrayBuffer(10 * Float64Array.BYTES_PER_ELEMENT);
+    var sf64a = new Float64Array(sab2);
+    sf64a[0] = 0;
+    assertEquals(v, Atomics.store(sf64a, 0, v));
+    assertEquals(v, sf64a[0]);
+  });
+})();
+
+(function TestAdd() {
+  IntegerTypedArrayConstructors.forEach(function(t) {
+    var sab = new SharedArrayBuffer(10 * t.constr.BYTES_PER_ELEMENT);
+    var sta = new t.constr(sab);
+    var name = Object.prototype.toString.call(sta);
+    for (var i = 0; i < 10; ++i) {
+      assertEquals(0, Atomics.add(sta, i, 50), name);
+      assertEquals(50, sta[i], name);
+
+      assertEquals(50, Atomics.add(sta, i, 70), name);
+      assertEquals(120, sta[i], name);
+    }
+  });
+
+  IntegerTypedArrayConstructors.forEach(function(t) {
+    var sab = new SharedArrayBuffer(10 * t.constr.BYTES_PER_ELEMENT);
+    var sta = new t.constr(sab);
+    var name = Object.prototype.toString.call(sta);
+    var range = t.max - t.min + 1;
+    var add;
+
+    for (add = -range; add <= range; add += range) {
+      sta[0] = t.max;
+      valWrapped = t.min;
+      assertEquals(t.max, Atomics.add(sta, 0, add + 1), name);
+      assertEquals(t.min, sta[0], name);
+
+      assertEquals(t.min, Atomics.add(sta, 0, add - 1), name);
+      assertEquals(t.max, sta[0], name);
+    }
+  });
+})();
+
+(function TestSub() {
+  IntegerTypedArrayConstructors.forEach(function(t) {
+    var sab = new SharedArrayBuffer(10 * t.constr.BYTES_PER_ELEMENT);
+    var sta = new t.constr(sab);
+    var name = Object.prototype.toString.call(sta);
+    for (var i = 0; i < 10; ++i) {
+      sta[i] = 120;
+      assertEquals(120, Atomics.sub(sta, i, 50), name);
+      assertEquals(70, sta[i], name);
+
+      assertEquals(70, Atomics.sub(sta, i, 70), name);
+      assertEquals(0, sta[i], name);
+    }
+  });
+
+  IntegerTypedArrayConstructors.forEach(function(t) {
+    var sab = new SharedArrayBuffer(10 * t.constr.BYTES_PER_ELEMENT);
+    var sta = new t.constr(sab);
+    var name = Object.prototype.toString.call(sta);
+    var range = t.max - t.min + 1;
+    var add;
+
+    for (add = -range; add <= range; add += range) {
+      sta[0] = t.max;
+      valWrapped = t.min;
+      assertEquals(t.max, Atomics.sub(sta, 0, add - 1), name);
+      assertEquals(t.min, sta[0], name);
+
+      assertEquals(t.min, Atomics.sub(sta, 0, add + 1), name);
+      assertEquals(t.max, sta[0], name);
+    }
+  });
+})();
+
+(function TestAnd() {
+  IntegerTypedArrayConstructors.forEach(function(t) {
+    var sab = new SharedArrayBuffer(10 * t.constr.BYTES_PER_ELEMENT);
+    var sta = new t.constr(sab);
+    var name = Object.prototype.toString.call(sta);
+    for (var i = 0; i < 10; ++i) {
+      sta[i] = 0x3f;
+      assertEquals(0x3f, Atomics.and(sta, i, 0x30), name);
+      assertEquals(0x30, sta[i], name);
+
+      assertEquals(0x30, Atomics.and(sta, i, 0x20), name);
+      assertEquals(0x20, sta[i], name);
+    }
+  });
+
+  IntegerTypedArrayConstructors.forEach(function(t) {
+    var sab = new SharedArrayBuffer(10 * t.constr.BYTES_PER_ELEMENT);
+    var sta = new t.constr(sab);
+    var name = Object.prototype.toString.call(sta);
+    var range = t.max - t.min + 1;
+    var add;
+
+    // There's no way to wrap results with logical operators, just test that
+    // using an out-of-range value is properly masked.
+    for (add = -range; add <= range; add += range) {
+      sta[0] = 0xf;
+      assertEquals(0xf, Atomics.and(sta, 0, 0x3 + add), name);
+      assertEquals(0x3, sta[0], name);
+    }
+  });
+})();
+
+(function TestOr() {
+  IntegerTypedArrayConstructors.forEach(function(t) {
+    var sab = new SharedArrayBuffer(10 * t.constr.BYTES_PER_ELEMENT);
+    var sta = new t.constr(sab);
+    var name = Object.prototype.toString.call(sta);
+    for (var i = 0; i < 10; ++i) {
+      sta[i] = 0x30;
+      assertEquals(0x30, Atomics.or(sta, i, 0x1c), name);
+      assertEquals(0x3c, sta[i], name);
+
+      assertEquals(0x3c, Atomics.or(sta, i, 0x09), name);
+      assertEquals(0x3d, sta[i], name);
+    }
+  });
+
+  IntegerTypedArrayConstructors.forEach(function(t) {
+    var sab = new SharedArrayBuffer(10 * t.constr.BYTES_PER_ELEMENT);
+    var sta = new t.constr(sab);
+    var name = Object.prototype.toString.call(sta);
+    var range = t.max - t.min + 1;
+    var add;
+
+    // There's no way to wrap results with logical operators, just test that
+    // using an out-of-range value is properly masked.
+    for (add = -range; add <= range; add += range) {
+      sta[0] = 0x12;
+      assertEquals(0x12, Atomics.or(sta, 0, 0x22 + add), name);
+      assertEquals(0x32, sta[0], name);
+    }
+  });
+})();
+
+(function TestXor() {
+  IntegerTypedArrayConstructors.forEach(function(t) {
+    var sab = new SharedArrayBuffer(10 * t.constr.BYTES_PER_ELEMENT);
+    var sta = new t.constr(sab);
+    var name = Object.prototype.toString.call(sta);
+    for (var i = 0; i < 10; ++i) {
+      sta[i] = 0x30;
+      assertEquals(0x30, Atomics.xor(sta, i, 0x1c), name);
+      assertEquals(0x2c, sta[i], name);
+
+      assertEquals(0x2c, Atomics.xor(sta, i, 0x09), name);
+      assertEquals(0x25, sta[i], name);
+    }
+  });
+
+  IntegerTypedArrayConstructors.forEach(function(t) {
+    var sab = new SharedArrayBuffer(10 * t.constr.BYTES_PER_ELEMENT);
+    var sta = new t.constr(sab);
+    var name = Object.prototype.toString.call(sta);
+    var range = t.max - t.min + 1;
+    var add;
+
+    // There's no way to wrap results with logical operators, just test that
+    // using an out-of-range value is properly masked.
+    for (add = -range; add <= range; add += range) {
+      sta[0] = 0x12;
+      assertEquals(0x12, Atomics.xor(sta, 0, 0x22 + add), name);
+      assertEquals(0x30, sta[0], name);
+    }
+  });
+})();
+
+(function TestExchange() {
+  IntegerTypedArrayConstructors.forEach(function(t) {
+    var sab = new SharedArrayBuffer(10 * t.constr.BYTES_PER_ELEMENT);
+    var sta = new t.constr(sab);
+    var name = Object.prototype.toString.call(sta);
+    for (var i = 0; i < 10; ++i) {
+      sta[i] = 0x30;
+      assertEquals(0x30, Atomics.exchange(sta, i, 0x1c), name);
+      assertEquals(0x1c, sta[i], name);
+
+      assertEquals(0x1c, Atomics.exchange(sta, i, 0x09), name);
+      assertEquals(0x09, sta[i], name);
+    }
+  });
+
+  IntegerTypedArrayConstructors.forEach(function(t) {
+    var sab = new SharedArrayBuffer(10 * t.constr.BYTES_PER_ELEMENT);
+    var sta = new t.constr(sab);
+    var name = Object.prototype.toString.call(sta);
+    var range = t.max - t.min + 1;
+    var add;
+
+    // There's no way to wrap results with logical operators, just test that
+    // using an out-of-range value is properly masked.
+    for (add = -range; add <= range; add += range) {
+      sta[0] = 0x12;
+      assertEquals(0x12, Atomics.exchange(sta, 0, 0x22 + add), name);
+      assertEquals(0x22, sta[0], name);
+    }
+  });
+})();
+
+(function TestIsLockFree() {
+  // For all platforms we support, 1, 2 and 4 bytes should be lock-free.
+  assertEquals(true, Atomics.isLockFree(1));
+  assertEquals(true, Atomics.isLockFree(2));
+  assertEquals(true, Atomics.isLockFree(4));
+
+  // Sizes that aren't equal to a typedarray BYTES_PER_ELEMENT always return
+  // false.
+  var validSizes = {};
+  TypedArrayConstructors.forEach(function(t) {
+    validSizes[t.constr.BYTES_PER_ELEMENT] = true;
+  });
+
+  for (var i = 0; i < 1000; ++i) {
+    if (!validSizes[i]) {
+      assertEquals(false, Atomics.isLockFree(i));
+    }
+  }
+})();