[change-array-by-copy] Implement with

Bug: v8:12764
Change-Id: I67b9b0e4f3c7ca6a2719c234b7f7605f07f86b28
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3671760
Reviewed-by: Marja Hölttä <marja@chromium.org>
Commit-Queue: Shu-yu Guo <syg@chromium.org>
Reviewed-by: Adam Klein <adamk@chromium.org>
Cr-Commit-Position: refs/heads/main@{#80874}

BUILD.bazel

@@ -783,6 +783,7 @@ filegroup(
         "src/builtins/array-splice.tq",
         "src/builtins/array-to-reversed.tq",
         "src/builtins/array-unshift.tq",
+        "src/builtins/array-with.tq",
         "src/builtins/array.tq",
         "src/builtins/arraybuffer.tq",
         "src/builtins/base.tq",
@@ -883,6 +884,7 @@ filegroup(
         "src/builtins/typed-array-subarray.tq",
         "src/builtins/typed-array-to-reversed.tq",
         "src/builtins/typed-array-values.tq",
+        "src/builtins/typed-array-with.tq",
         "src/builtins/typed-array.tq",
         "src/builtins/weak-ref.tq",
         "src/ic/handler-configuration.tq",

BUILD.gn

@@ -1683,6 +1683,7 @@ torque_files = [
   "src/builtins/array-splice.tq",
   "src/builtins/array-to-reversed.tq",
   "src/builtins/array-unshift.tq",
+  "src/builtins/array-with.tq",
   "src/builtins/array.tq",
   "src/builtins/arraybuffer.tq",
   "src/builtins/base.tq",
@@ -1783,6 +1784,7 @@ torque_files = [
   "src/builtins/typed-array-subarray.tq",
   "src/builtins/typed-array-to-reversed.tq",
   "src/builtins/typed-array-values.tq",
+  "src/builtins/typed-array-with.tq",
   "src/builtins/typed-array.tq",
   "src/builtins/weak-ref.tq",
   "src/ic/handler-configuration.tq",

src/builtins/array-with.tq

@@ -0,0 +1,89 @@
+// Copyright 2022 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.
+
+namespace array {
+transitioning macro TryFastPackedArrayWith(implicit context: Context)(
+    receiver: JSReceiver, len: Number, actualIndex: Number,
+    value: JSAny): JSArray labels Slow {
+  // Array#with does not preserve holes and always creates packed Arrays. Holes
+  // in the source array-like are treated like any other element and the value
+  // is computed with Get. So, there are only fast paths for packed elements.
+  const array: FastJSArray = Cast<FastJSArray>(receiver) otherwise Slow;
+  if (IsFastPackedElementsKind(array.map.elements_kind)) {
+    const lenSmi = Cast<Smi>(len) otherwise Slow;
+    // It is possible that the index coercion shrunk the source array, in which
+    // case go to the slow case.
+    if (lenSmi > array.length) goto Slow;
+
+    // Steps 7-9 done by copying and overriding the value at index.
+    const copy = ExtractFastJSArray(context, array, 0, lenSmi);
+    FastCreateDataProperty(copy, actualIndex, value);
+
+    // 10. Return A.
+    return copy;
+  }
+  goto Slow;
+}
+
+transitioning macro GenericArrayWith(
+    context: Context, receiver: JSReceiver, len: Number, actualIndex: Number,
+    value: JSAny): JSArray {
+  // 7. Let A be ? ArrayCreate(𝔽(len)).
+  const copy = ArrayCreate(len);
+
+  // 8. Let k be 0.
+  let k: Number = 0;
+
+  // 9. Repeat, while k < len,
+  while (k < len) {
+    // a. Let Pk be ! ToString(𝔽(k)).
+    // b. If k is actualIndex, let fromValue be value.
+    // c. Else, let fromValue be ? Get(O, Pk).
+    const fromValue = k == actualIndex ? value : GetProperty(receiver, k);
+
+    // d. Perform ! CreateDataPropertyOrThrow(A, Pk, fromValue).
+    FastCreateDataProperty(copy, k, fromValue);
+
+    // e. Set k to k + 1.
+    ++k;
+  }
+
+  // 10. Return A.
+  return copy;
+}
+
+// https://tc39.es/proposal-change-array-by-copy/#sec-array.prototype.with
+transitioning javascript builtin ArrayPrototypeWith(
+    js-implicit context: NativeContext, receiver: JSAny)(...arguments): JSAny {
+  const index = arguments[0];
+  const value = arguments[1];
+
+  // 1. Let O be ? ToObject(this value).
+  const object: JSReceiver = ToObject_Inline(context, receiver);
+
+  // 2. Let len be ? LengthOfArrayLike(O).
+  const len: Number = GetLengthProperty(object);
+
+  try {
+    // 3. Let relativeIndex be ? ToIntegerOrInfinity(index).
+    const relativeIndex = ToInteger_Inline(index);
+
+    // 4. If relativeIndex ≥ 0, let actualIndex be relativeIndex.
+    // 5. Else, let actualIndex be len + relativeIndex.
+    // 6. If actualIndex ≥ len or actualIndex < 0, throw a RangeError exception.
+    const actualIndex =
+        ConvertRelativeIndex(relativeIndex, len) otherwise OutOfBounds,
+          OutOfBounds;
+
+    try {
+      return TryFastPackedArrayWith(object, len, actualIndex, value)
+          otherwise Slow;
+    } label Slow {
+      return GenericArrayWith(context, object, len, actualIndex, value);
+    }
+  } label OutOfBounds deferred {
+    ThrowRangeError(MessageTemplate::kInvalid, 'index', index);
+  }
+}
+}

src/builtins/base.tq

@@ -360,9 +360,11 @@ const kBigIntMaxLength: constexpr intptr generates 'BigInt::kMaxLength';
 
 extern enum MessageTemplate {
   kAllPromisesRejected,
+  kInvalid,
   kInvalidArrayBufferLength,
   kInvalidArrayLength,
   kInvalidIndex,
+  kInvalidTypedArrayIndex,
   kNotConstructor,
   kNotGeneric,
   kCalledNonCallable,
@@ -644,6 +646,8 @@ transitioning macro ToInteger_Inline(implicit context: Context)(input: JSAny):
   }
 }
 
+extern macro ToBigInt(Context, JSAny): BigInt;
+
 extern enum BigIntHandling extends int32
 constexpr 'CodeStubAssembler::BigIntHandling' { kConvertToNumber, kThrow }
 
@@ -683,6 +687,8 @@ extern macro ThrowRangeError(implicit context: Context)(
     constexpr MessageTemplate): never;
 extern macro ThrowRangeError(implicit context: Context)(
     constexpr MessageTemplate, Object): never;
+extern macro ThrowRangeError(implicit context: Context)(
+    constexpr MessageTemplate, Object, Object): never;
 extern macro ThrowTypeError(implicit context: Context)(
     constexpr MessageTemplate): never;
 extern macro ThrowTypeError(implicit context: Context)(
@@ -828,6 +834,7 @@ extern macro IsElementsKindInRange(
     ElementsKind, constexpr ElementsKind, constexpr ElementsKind): bool;
 
 extern macro IsFastElementsKind(constexpr ElementsKind): constexpr bool;
+extern macro IsFastPackedElementsKind(constexpr ElementsKind): constexpr bool;
 extern macro IsDoubleElementsKind(constexpr ElementsKind): constexpr bool;
 
 extern macro GetNonRabGsabElementsKind(ElementsKind): ElementsKind;
@@ -1306,6 +1313,7 @@ extern macro BasicLoadNumberDictionaryElement(NumberDictionary, intptr): JSAny
     labels NotData, IfHole;
 
 extern macro IsFastElementsKind(ElementsKind): bool;
+extern macro IsFastPackedElementsKind(ElementsKind): bool;
 extern macro IsDoubleElementsKind(ElementsKind): bool;
 extern macro IsFastSmiOrTaggedElementsKind(ElementsKind): bool;
 extern macro IsFastSmiElementsKind(ElementsKind): bool;

src/builtins/data-view.tq

@@ -536,7 +536,6 @@ transitioning javascript builtin DataViewPrototypeGetBigInt64(
 }
 
 extern macro ToNumber(Context, JSAny): Number;
-extern macro ToBigInt(Context, JSAny): BigInt;
 extern macro TruncateFloat64ToWord32(float64): uint32;
 
 extern macro DataViewBuiltinsAssembler::StoreWord8(

src/builtins/typed-array-with.tq

@@ -0,0 +1,96 @@
+// Copyright 2022 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.
+
+namespace typed_array {
+const kBuiltinNameWith: constexpr string = '%TypedArray%.prototype.with';
+
+// https://tc39.es/proposal-change-array-by-copy/#sec-%typedarray%.prototype.with
+transitioning javascript builtin TypedArrayPrototypeWith(
+    js-implicit context: NativeContext, receiver: JSAny)(...arguments): JSAny {
+  const index = arguments[0];
+  let value: JSAny = arguments[1];
+
+  try {
+    // 1. Let O be the this value.
+    // 2. Perform ? ValidateTypedArray(O).
+    // 3. Let len be O.[[ArrayLength]].
+    const array: JSTypedArray =
+        Cast<JSTypedArray>(receiver) otherwise NotTypedArray;
+    let attachedArrayAndLength = EnsureAttachedAndReadLength(array)
+        otherwise IsDetachedOrOutOfBounds;
+    const originalLength = attachedArrayAndLength.length;
+
+    // TODO(v8:12764): This change is waiting on upstream
+    // https://github.com/tc39/proposal-change-array-by-copy/issues/85
+    if (IsBigInt64ElementsKind(array.elements_kind)) {
+      // 4. If O.[[ContentType]] is BigInt, set value to ? ToBigInt(value).
+      value = ToBigInt(context, value);
+    } else {
+      // 5. Else, set value to ? ToNumber(value).
+      value = ToNumber_Inline(value);
+    }
+
+    // 6. Let relativeIndex be ? ToIntegerOrInfinity(index).
+    const relativeIndex = ToInteger_Inline(index);
+
+    // 7. If relativeIndex ≥ 0, let actualIndex be relativeIndex.
+    // 8. Else, let actualIndex be len + relativeIndex.
+    const actualIndex: uintptr = ConvertRelativeIndex(
+        relativeIndex, originalLength) otherwise IndexOutOfBounds,
+                       IndexOutOfBounds;
+
+    // 9. If ! IsValidIntegerIndex(O, 𝔽(actualIndex)) is false, throw a
+    // RangeError exception.
+    attachedArrayAndLength = EnsureAttachedAndReadLength(array)
+        otherwise IndexOutOfBounds;
+    if (actualIndex >= attachedArrayAndLength.length) goto IndexOutOfBounds;
+
+    // 10. Let A be ? TypedArrayCreateSameType(O, « 𝔽(len) »).
+    const copy = TypedArrayCreateSameType(array, originalLength);
+    const fastCopyableLength =
+        UintPtrMin(originalLength, attachedArrayAndLength.length);
+
+    // Steps 11-12's copy loop implemented by memmove.
+    const info = GetTypedArrayElementsInfo(copy);
+    const countBytes: uintptr =
+        info.CalculateByteLength(fastCopyableLength) otherwise unreachable;
+    // TypedArrayCreateSameType always use built-in constructors, and so cannot
+    // cause the source TypedArray to become detached or OOB.
+    const srcPtr: RawPtr = array.data_ptr;
+
+    if (IsSharedArrayBuffer(array.buffer)) {
+      CallCRelaxedMemmove(copy.data_ptr, srcPtr, countBytes);
+    } else {
+      CallCMemmove(copy.data_ptr, srcPtr, countBytes);
+    }
+
+    // b. If k is actualIndex, then
+    //   i. Perform ? Set(A, Pk, value, true).
+    const accessor: TypedArrayAccessor =
+        GetTypedArrayAccessor(copy.elements_kind);
+    accessor.StoreJSAny(context, copy, actualIndex, value)
+        otherwise unreachable;
+
+    // Fill the remainder with undefined, in case of resize during parameter
+    // conversion. This is not the same as doing nothing because:
+    // - Undefined convert to NaN, which is observable when stored into
+    //   Float32 and Float64Arrays
+    // - Undefined cannot convert to BigInt and throws
+    let k: uintptr = fastCopyableLength;
+    while (k < copy.length) {
+      accessor.StoreJSAny(context, copy, k, Undefined) otherwise unreachable;
+      ++k;
+    }
+
+    // 11. Return A.
+    return copy;
+  } label IndexOutOfBounds deferred {
+    ThrowRangeError(MessageTemplate::kInvalidTypedArrayIndex);
+  } label NotTypedArray deferred {
+    ThrowTypeError(MessageTemplate::kNotTypedArray, kBuiltinNameWith);
+  } label IsDetachedOrOutOfBounds deferred {
+    ThrowTypeError(MessageTemplate::kDetachedOperation, kBuiltinNameWith);
+  }
+}
+}

src/builtins/typed-array.tq

@@ -298,7 +298,7 @@ builtin StoreTypedElementNumeric<T : type extends ElementsKind>(
   return kStoreSucceded;
 }
 
-// Returns True on sucess or False if the typedArrays was detached.
+// Returns True on success or False if the typedArrays was detached.
 builtin StoreTypedElementJSAny<T : type extends ElementsKind>(
     context: Context, typedArray: JSTypedArray, index: uintptr,
     value: JSAny): Smi {

src/codegen/code-stub-assembler.cc

@@ -14492,6 +14492,18 @@ TNode<BoolT> CodeStubAssembler::IsFastElementsKind(
                                Int32Constant(LAST_FAST_ELEMENTS_KIND));
 }
 
+TNode<BoolT> CodeStubAssembler::IsFastPackedElementsKind(
+    TNode<Int32T> elements_kind) {
+  static_assert(FIRST_ELEMENTS_KIND == FIRST_FAST_ELEMENTS_KIND);
+  // ElementsKind values that are even are packed. See
+  // internal::IsFastPackedElementsKind.
+  static_assert((~PACKED_SMI_ELEMENTS & 1) == 1);
+  static_assert((~PACKED_ELEMENTS & 1) == 1);
+  static_assert((~PACKED_DOUBLE_ELEMENTS & 1) == 1);
+  return Word32And(IsNotSetWord32(elements_kind, 1),
+                   IsFastElementsKind(elements_kind));
+}
+
 TNode<BoolT> CodeStubAssembler::IsFastOrNonExtensibleOrSealedElementsKind(
     TNode<Int32T> elements_kind) {
   static_assert(FIRST_ELEMENTS_KIND == FIRST_FAST_ELEMENTS_KIND);

src/codegen/code-stub-assembler.h

@@ -2719,6 +2719,10 @@ class V8_EXPORT_PRIVATE CodeStubAssembler
   bool IsFastElementsKind(ElementsKind kind) {
     return v8::internal::IsFastElementsKind(kind);
   }
+  TNode<BoolT> IsFastPackedElementsKind(TNode<Int32T> elements_kind);
+  bool IsFastPackedElementsKind(ElementsKind kind) {
+    return v8::internal::IsFastPackedElementsKind(kind);
+  }
   TNode<BoolT> IsFastOrNonExtensibleOrSealedElementsKind(
       TNode<Int32T> elements_kind);
 

src/init/bootstrapper.cc

@@ -4497,6 +4497,8 @@ void Genesis::InitializeGlobal_harmony_change_array_by_copy() {
 
     SimpleInstallFunction(isolate_, array_prototype, "toReversed",
                           Builtin::kArrayPrototypeToReversed, 0, true);
+    SimpleInstallFunction(isolate_, array_prototype, "with",
+                          Builtin::kArrayPrototypeWith, 2, true);
 
     Handle<JSObject> unscopables = Handle<JSObject>::cast(
         JSObject::GetProperty(isolate(), array_prototype,
@@ -4511,6 +4513,8 @@ void Genesis::InitializeGlobal_harmony_change_array_by_copy() {
                                isolate());
     SimpleInstallFunction(isolate_, prototype, "toReversed",
                           Builtin::kTypedArrayPrototypeToReversed, 0, true);
+    SimpleInstallFunction(isolate_, prototype, "with",
+                          Builtin::kTypedArrayPrototypeWith, 2, true);
   }
 }
 

test/mjsunit/harmony/array-with.js

@@ -0,0 +1,136 @@
+// Copyright 2022 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-change-array-by-copy
+
+"use strict";
+
+assertEquals(2, Array.prototype.with.length);
+assertEquals("with", Array.prototype.with.name);
+
+const values = [1, 1.1, true, false, undefined, null, "foo", {}];
+
+(function TestSmiPacked() {
+  let a = [1,2,3,4];
+  for (let v of values) {
+    let b = a.with(1, v);
+    assertEquals([1,2,3,4], a);
+    assertEquals([1,v,3,4], b);
+    assertFalse(a === b);
+    let c = a.with(-1, v);
+    assertEquals([1,2,3,4], a);
+    assertEquals([1,2,3,v], c);
+    assertFalse(a === c);
+  }
+})();
+
+(function TestDoublePacked() {
+  let a = [1.1,2.2,3.3,4.4];
+  for (let v of values) {
+    let b = a.with(1, v);
+    assertEquals([1.1,2.2,3.3,4.4], a);
+    assertEquals([1.1,v,3.3,4.4], b);
+    assertFalse(a === b);
+    let c = a.with(-1, v);
+    assertEquals([1.1,2.2,3.3,4.4], a);
+    assertEquals([1.1,2.2,3.3,v], c);
+    assertFalse(a === c);
+  }
+})();
+
+(function TestPacked() {
+  let a = [true,false,1,42.42];
+  for (let v of values) {
+    let b = a.with(1, v);
+    assertEquals([true,false,1,42.42], a);
+    assertEquals([true,v,1,42.42], b);
+    assertFalse(a === b);
+    let c = a.with(-1, v);
+    assertEquals([true,false,1,42.42], a);
+    assertEquals([true,false,1,v], c);
+    assertFalse(a === c);
+  }
+})();
+
+(function TestGeneric() {
+  let a = { length: 4,
+            get "0"() { return "hello"; },
+            get "1"() { return "cursed"; },
+            get "2"() { return "java"; },
+            get "3"() { return "script" } };
+  for (let v of values) {
+    let b = Array.prototype.with.call(a, 1, v);
+    assertEquals("cursed", a[1]);
+    assertEquals(["hello",v,"java","script"], b);
+    assertFalse(a === b);
+    assertTrue(Array.isArray(b));
+    assertEquals(Array, b.constructor);
+    let c = Array.prototype.with.call(a, -1, v);
+    assertEquals("script", a[a.length-1]);
+    assertEquals(["hello","cursed","java",v], c);
+    assertFalse(a === c);
+    assertTrue(Array.isArray(c));
+    assertEquals(Array, c.constructor);
+  }
+})();
+
+(function TestTooBig() {
+  let a = { length: Math.pow(2, 32) };
+  assertThrows(() => Array.prototype.with.call(a, 1, 42), RangeError);
+})();
+
+(function TestNoSpecies() {
+  class MyArray extends Array {
+    static get [Symbol.species]() { return MyArray; }
+  }
+  let a = new MyArray();
+  a.length = 4;
+  assertEquals(Array, a.with(1,42).constructor);
+})();
+
+(function TestOutOfBounds() {
+  let a = [1,2,3,4];
+  assertThrows(() => { a.with(a.length, 42); }, RangeError);
+  assertThrows(() => { a.with(-a.length - 1, 42); }, RangeError);
+})();
+
+(function TestIndexShenanigans() {
+  let a = [1,2,3,4];
+  // The index can resize and do other shenanigans since it's coerced before
+  // iteration.
+  let b = a.with({ valueOf() { a.length = 2; return 1; } }, 42);
+  assertEquals([1,2], a);
+  assertEquals([1,42,undefined,undefined], b);
+
+  // Holey.
+  a = [1,2,3,4,,,];
+  let c = a.with({ valueOf() { a.length = 2; return 1; } }, 42);
+  assertEquals([1,2], a);
+  assertEquals([1,42,undefined,undefined,undefined,undefined], c);
+
+  a = [1,2,3,4];
+  let d = a.with({ valueOf() { a[2] = "barf"; return 1; } }, 42);
+  assertEquals([1,2,"barf",4], a);
+  assertEquals([1,42,"barf",4], d);
+})();
+
+(function TestValuePassthrough() {
+  let a = [1,2,3,4];
+  // The value isn't used in any meaningful sense by with.
+  a.with(1, { valueOf() { assertUnreachable(); } });
+})();
+
+// All tests after this have an invalidated elements-on-prototype protector.
+(function TestNoHoles() {
+  let a = [,,,,];
+  Array.prototype[3] = "on proto";
+  for (let v of values) {
+    let b = a.with(1,v);
+    assertEquals([undefined,v,undefined,"on proto"], b);
+    assertTrue(b.hasOwnProperty('0'));
+    assertTrue(b.hasOwnProperty('1'));
+    assertTrue(b.hasOwnProperty('2'));
+    assertTrue(b.hasOwnProperty('3'));
+  }
+})();

test/mjsunit/harmony/typedarray-with.js

@@ -0,0 +1,310 @@
+// Copyright 2022 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-change-array-by-copy --harmony-rab-gsab
+// Flags: --allow-natives-syntax
+
+"use strict";
+
+d8.file.execute('test/mjsunit/typedarray-helpers.js');
+
+function NormalizeValue(array, value) {
+  if (array instanceof BigInt64Array || array instanceof BigUint64Array) {
+    return BigInt(value);
+  }
+  return value;
+}
+
+function CheckWith(orig, index, indexNotEvil, v, vNotEvil) {
+  const origLen = orig.length;
+  const absoluteIndex = indexNotEvil < 0
+        ? indexNotEvil + orig.length
+        : indexNotEvil;
+  const origVAtIndex = orig[absoluteIndex];
+  const copy = orig.with(index, v);
+
+  assertEquals(origLen, copy.length);
+  for (let i = 0; i < origLen; i++) {
+    assertEquals(i == absoluteIndex ? vNotEvil : orig[i], copy[i]);
+  }
+  assertEquals(origVAtIndex, orig[absoluteIndex]);
+  assertFalse(copy === orig);
+  assertFalse(copy.buffer === orig.buffer);
+}
+
+function CheckWithShrunkOrDetached(orig, v, vNotEvil) {
+  const origLen = orig.length;
+  if (orig instanceof BigInt64Array ||
+      orig instanceof BigUint64Array) {
+    // This is funny. For BigInt TAs this throws because when shrinking the
+    // source array, the remainder of the copy is filled with undefineds because
+    // OOB TA loads return undefined, but undefined can't be coerced to BigInt
+    // and throw a TypeError.
+    assertThrows(() => { orig.with(1, v); }, TypeError);
+    return;
+  }
+
+  const copy = orig.with(1, v);
+  assertEquals(origLen, copy.length);
+  assertEquals(NormalizeValue(copy, 0), copy[0]);
+  assertEquals(vNotEvil, copy[1]);
+  for (let i = 2; i < copy.length; i++) {
+    if (copy instanceof Float32Array || copy instanceof Float64Array) {
+      assertEquals(NaN, copy[i]);
+    } else {
+      assertEquals(0, copy[i]);
+    }
+  }
+}
+
+(function TestSurface() {
+  for (let TA of ctors) {
+    assertEquals(2, TA.prototype.with.length);
+    assertEquals("with", TA.prototype.with.name);
+  }
+})();
+
+(function TestBasic() {
+  for (let TA of ctors) {
+    let a = new TA(4);
+    const v = NormalizeValue(a, 42);
+    for (let i = 0; i < 4; i++) {
+      WriteToTypedArray(a, i, i);
+    }
+    CheckWith(a, 1, 1, v, v);
+    CheckWith(a, -1, -1, v, v);
+  }
+})();
+
+(function TestOutOfBounds() {
+  for (let TA of ctors) {
+    let a = new TA(4);
+    const v = NormalizeValue(a, 42);
+    assertThrows(() => { a.with(a.length, v); }, RangeError);
+    assertThrows(() => { a.with(-a.length - 1, v); }, RangeError);
+  }
+})();
+
+(function TestNonTypedArray() {
+  for (let TA of ctors) {
+    assertThrows(() => { TA.prototype.with.call([1,2,3,4], 1, 42); }, TypeError);
+  }
+})();
+
+(function TestResizableBuffer() {
+  for (let TA of ctors) {
+    const rab = CreateResizableArrayBuffer(4 * TA.BYTES_PER_ELEMENT,
+                                           8 * TA.BYTES_PER_ELEMENT);
+    const fixedLength = new TA(rab, 0, 4);
+    const fixedLengthWithOffset = new TA(rab, 2 * TA.BYTES_PER_ELEMENT, 2);
+    const lengthTracking = new TA(rab, 0);
+    const lengthTrackingWithOffset = new TA(rab, 2 * TA.BYTES_PER_ELEMENT);
+
+    const v = NormalizeValue(fixedLength, 42);
+
+    // Write some data into the array.
+    const taWrite = new TA(rab);
+    for (let i = 0; i < 4; i++) {
+      WriteToTypedArray(taWrite, i, i);
+    }
+
+    // Orig. array: [0, 1, 2, 3]
+    //              [0, 1, 2, 3] << fixedLength
+    //                    [2, 3] << fixedLengthWithOffset
+    //              [0, 1, 2, 3, ...] << lengthTracking
+    //                    [2, 3, ...] << lengthTrackingWithOffset
+
+    CheckWith(fixedLength, 1, 1, v, v);
+    CheckWith(fixedLengthWithOffset, 1, 1, v, v);
+    CheckWith(lengthTracking, 1, 1, v, v);
+    CheckWith(lengthTrackingWithOffset, 1, 1, v, v);
+
+    CheckWith(fixedLength, -1, -1, v, v);
+    CheckWith(fixedLengthWithOffset, -1, -1, v, v);
+    CheckWith(lengthTracking, -1, -1, v, v);
+    CheckWith(lengthTrackingWithOffset, -1, -1, v, v);
+
+    // Shrink so that the TAs with offset go out of bounds.
+    rab.resize(1 * TA.BYTES_PER_ELEMENT);
+    WriteToTypedArray(taWrite, 0, 0);
+
+    assertThrows(() => { fixedLength.with(0, v); }, TypeError);
+    assertThrows(() => { fixedLengthWithOffset.with(0, v); }, TypeError);
+    CheckWith(lengthTracking, 0, 0, v, v);
+    assertThrows(() => { lengthTrackingWithOffset.with(0, v); }, TypeError);
+
+    // Shrink to zero.
+    rab.resize(0);
+
+    assertThrows(() => { fixedLength.with(0, v); }, TypeError);
+    assertThrows(() => { fixedLengthWithOffset.with(0, v); }, TypeError);
+    assertThrows(() => { lengthTracking.with(0, v); }, RangeError);
+    assertThrows(() => { lengthTrackingWithOffset.copyWithin(0, 1, 1); },
+                 TypeError);
+
+    // Grow so that all TAs are back in-bounds.
+    rab.resize(6 * TA.BYTES_PER_ELEMENT);
+    for (let i = 0; i < 6; ++i) {
+      WriteToTypedArray(taWrite, i, i);
+    }
+
+    // Orig. array: [0, 1, 2, 3, 4, 5]
+    //              [0, 1, 2, 3] << fixedLength
+    //                    [2, 3] << fixedLengthWithOffset
+    //              [0, 1, 2, 3, 4, 5, ...] << lengthTracking
+    //                    [2, 3, 4, 5, ...] << lengthTrackingWithOffset
+
+    CheckWith(fixedLength, 1, 1, v, v);
+    CheckWith(fixedLengthWithOffset, 1, 1, v, v);
+    CheckWith(lengthTracking, 4, 4, v, v);
+    CheckWith(lengthTrackingWithOffset, 1, 1, v, v);
+
+    CheckWith(fixedLength, -1, -1, v, v);
+    CheckWith(fixedLengthWithOffset, -1, -1, v, v);
+    CheckWith(lengthTracking, -4, -4, v, v);
+    CheckWith(lengthTrackingWithOffset, -3, -3, v, v);
+  }
+})();
+
+(function TestParameterConversionShrinks() {
+  for (let TA of ctors) {
+    const rab = CreateResizableArrayBuffer(4 * TA.BYTES_PER_ELEMENT,
+                                           8 * TA.BYTES_PER_ELEMENT);
+    const fixedLength = new TA(rab, 0, 4);
+    const v = NormalizeValue(fixedLength, 42);
+
+    const evilIndex = { valueOf: () => { rab.resize(2 * TA.BYTES_PER_ELEMENT);
+                                          return 2; }};
+    assertThrows(() => { fixedLength.with(evilIndex, v); },
+                 RangeError);
+
+    const evilV = { valueOf: () => { rab.resize(2 * TA.BYTES_PER_ELEMENT);
+                                      return v; }};
+    rab.resize(4 * TA.BYTES_PER_ELEMENT);
+    const lengthTracking = new TA(rab, 0);
+    CheckWithShrunkOrDetached(lengthTracking, evilV, v);
+  }
+})();
+
+(function TestParameterConversionGrows() {
+  for (let TA of ctors) {
+    const rab = CreateResizableArrayBuffer(4 * TA.BYTES_PER_ELEMENT,
+                                           8 * TA.BYTES_PER_ELEMENT);
+    const lengthTracking = new TA(rab, 0);
+    const v = NormalizeValue(lengthTracking, 42);
+
+    const evilIndex = { valueOf: () => { rab.resize(6 * TA.BYTES_PER_ELEMENT);
+                                          return 1; }};
+    const evilV = { valueOf: () => { rab.resize(6 * TA.BYTES_PER_ELEMENT);
+                                      return v; }};
+    CheckWith(lengthTracking, evilIndex, 1, v, v);
+    rab.resize(4 * TA.BYTES_PER_ELEMENT);
+    CheckWith(lengthTracking, 1, 1, evilV, v);
+  }
+})();
+
+(function TestParameterConversionDetaches() {
+  for (let TA of ctors) {
+    let rab = CreateResizableArrayBuffer(4 * TA.BYTES_PER_ELEMENT,
+                                         8 * TA.BYTES_PER_ELEMENT);
+    const fixedLength = new TA(rab, 0, 4);
+    const v = NormalizeValue(fixedLength, 42);
+
+    const evilIndex = { valueOf: () => { %ArrayBufferDetach(rab);
+                                          return 2; }};
+    assertThrows(() => { fixedLength.with(evilIndex, v); },
+                 RangeError);
+
+    rab = CreateResizableArrayBuffer(4 * TA.BYTES_PER_ELEMENT,
+                                     8 * TA.BYTES_PER_ELEMENT);
+    const lengthTracking = new TA(rab, 0);
+    const evilV = { valueOf: () => { %ArrayBufferDetach(rab);
+                                      return v; }};
+    assertThrows(() => { fixedLength.with(1, evilV); }, TypeError);
+  }
+})();
+
+(function TestGrowableSAB() {
+  for (let TA of ctors) {
+    const gsab = CreateGrowableSharedArrayBuffer(4 * TA.BYTES_PER_ELEMENT,
+                                                 8 * TA.BYTES_PER_ELEMENT);
+    const fixedLength = new TA(gsab, 0, 4);
+    const fixedLengthWithOffset = new TA(gsab, 2 * TA.BYTES_PER_ELEMENT, 2);
+    const lengthTracking = new TA(gsab, 0);
+    const lengthTrackingWithOffset = new TA(gsab, 2 * TA.BYTES_PER_ELEMENT);
+
+    const v = NormalizeValue(fixedLength, 42);
+
+    // Write some data into the array.
+    const taWrite = new TA(gsab);
+    for (let i = 0; i < 4; i++) {
+      WriteToTypedArray(taWrite, i, 2 * i);
+    }
+
+    // Orig. array: [0, 2, 4, 6]
+    //              [0, 2, 4, 6] << fixedLength
+    //                    [4, 6] << fixedLengthWithOffset
+    //              [0, 2, 4, 6, ...] << lengthTracking
+    //                    [4, 6, ...] << lengthTrackingWithOffset
+
+    CheckWith(fixedLength, 1, 1, v, v);
+    CheckWith(fixedLengthWithOffset, 1, 1, v, v);
+    CheckWith(lengthTracking, 1, 1, v, v);
+    CheckWith(lengthTrackingWithOffset, 1, 1, v, v);
+
+    CheckWith(fixedLength, -1, -1, v, v);
+    CheckWith(fixedLengthWithOffset, -1, -1, v, v);
+    CheckWith(lengthTracking, -1, -1, v, v);
+    CheckWith(lengthTrackingWithOffset, -1, -1, v, v);
+
+    // Grow.
+    gsab.grow(6 * TA.BYTES_PER_ELEMENT);
+    for (let i = 0; i < 6; ++i) {
+      WriteToTypedArray(taWrite, i, 2 * i);
+    }
+
+    // Orig. array: [0, 2, 4, 6, 8, 10]
+    //              [0, 2, 4, 6] << fixedLength
+    //                    [4, 6] << fixedLengthWithOffset
+    //              [0, 2, 4, 6, 8, 10, ...] << lengthTracking
+    //                    [4, 6, 8, 10, ...] << lengthTrackingWithOffset
+    CheckWith(fixedLength, 1, 1, v, v);
+    CheckWith(fixedLengthWithOffset, 1, 1, v, v);
+    CheckWith(lengthTracking, 4, 4, v, v);
+    CheckWith(lengthTrackingWithOffset, 1, 1, v, v);
+
+    CheckWith(fixedLength, -1, -1, v, v);
+    CheckWith(fixedLengthWithOffset, -1, -1, v, v);
+    CheckWith(lengthTracking, -4, -4, v, v);
+    CheckWith(lengthTrackingWithOffset, -3, -3, v, v);
+  }
+})();
+
+(function TestParameterConversionGrowsSAB() {
+  for (let TA of ctors) {
+    let gsab = CreateGrowableSharedArrayBuffer(4 * TA.BYTES_PER_ELEMENT,
+                                               8 * TA.BYTES_PER_ELEMENT);
+    let lengthTracking = new TA(gsab, 0);
+    const v = NormalizeValue(lengthTracking, 42);
+
+    const evilIndex = { valueOf: () => { gsab.grow(6 * TA.BYTES_PER_ELEMENT);
+                                          return 1; }};
+    const evilV = { valueOf: () => { gsab.grow(6 * TA.BYTES_PER_ELEMENT);
+                                      return v; }};
+    CheckWith(lengthTracking, evilIndex, 1, v, v);
+
+    gsab = CreateGrowableSharedArrayBuffer(4 * TA.BYTES_PER_ELEMENT,
+                                           8 * TA.BYTES_PER_ELEMENT);
+    lengthTracking = new TA(gsab, 0);
+    CheckWith(lengthTracking, 1, 1, evilV, v);
+  }
+})();
+
+(function TestNoSpecies() {
+  class MyUint8Array extends Uint8Array {
+    constructor(len) { super(len); }
+    static get [Symbol.species]() { return MyUint8Array; }
+  }
+  assertEquals(Uint8Array, (new MyUint8Array(4)).with(0, 42).constructor);
+})();

tools/v8heapconst.py

@@ -536,30 +536,30 @@ KNOWN_OBJECTS = {
   ("old_space", 0x04b35): "StringSplitCache",
   ("old_space", 0x04f3d): "RegExpMultipleCache",
   ("old_space", 0x05345): "BuiltinsConstantsTable",
-  ("old_space", 0x0577d): "AsyncFunctionAwaitRejectSharedFun",
-  ("old_space", 0x057a1): "AsyncFunctionAwaitResolveSharedFun",
-  ("old_space", 0x057c5): "AsyncGeneratorAwaitRejectSharedFun",
-  ("old_space", 0x057e9): "AsyncGeneratorAwaitResolveSharedFun",
-  ("old_space", 0x0580d): "AsyncGeneratorYieldResolveSharedFun",
-  ("old_space", 0x05831): "AsyncGeneratorReturnResolveSharedFun",
-  ("old_space", 0x05855): "AsyncGeneratorReturnClosedRejectSharedFun",
-  ("old_space", 0x05879): "AsyncGeneratorReturnClosedResolveSharedFun",
-  ("old_space", 0x0589d): "AsyncIteratorValueUnwrapSharedFun",
-  ("old_space", 0x058c1): "PromiseAllResolveElementSharedFun",
-  ("old_space", 0x058e5): "PromiseAllSettledResolveElementSharedFun",
-  ("old_space", 0x05909): "PromiseAllSettledRejectElementSharedFun",
-  ("old_space", 0x0592d): "PromiseAnyRejectElementSharedFun",
-  ("old_space", 0x05951): "PromiseCapabilityDefaultRejectSharedFun",
-  ("old_space", 0x05975): "PromiseCapabilityDefaultResolveSharedFun",
-  ("old_space", 0x05999): "PromiseCatchFinallySharedFun",
-  ("old_space", 0x059bd): "PromiseGetCapabilitiesExecutorSharedFun",
-  ("old_space", 0x059e1): "PromiseThenFinallySharedFun",
-  ("old_space", 0x05a05): "PromiseThrowerFinallySharedFun",
-  ("old_space", 0x05a29): "PromiseValueThunkFinallySharedFun",
-  ("old_space", 0x05a4d): "ProxyRevokeSharedFun",
-  ("old_space", 0x05a71): "ShadowRealmImportValueFulfilledSFI",
-  ("old_space", 0x05a95): "SourceTextModuleExecuteAsyncModuleFulfilledSFI",
-  ("old_space", 0x05ab9): "SourceTextModuleExecuteAsyncModuleRejectedSFI",
+  ("old_space", 0x05781): "AsyncFunctionAwaitRejectSharedFun",
+  ("old_space", 0x057a5): "AsyncFunctionAwaitResolveSharedFun",
+  ("old_space", 0x057c9): "AsyncGeneratorAwaitRejectSharedFun",
+  ("old_space", 0x057ed): "AsyncGeneratorAwaitResolveSharedFun",
+  ("old_space", 0x05811): "AsyncGeneratorYieldResolveSharedFun",
+  ("old_space", 0x05835): "AsyncGeneratorReturnResolveSharedFun",
+  ("old_space", 0x05859): "AsyncGeneratorReturnClosedRejectSharedFun",
+  ("old_space", 0x0587d): "AsyncGeneratorReturnClosedResolveSharedFun",
+  ("old_space", 0x058a1): "AsyncIteratorValueUnwrapSharedFun",
+  ("old_space", 0x058c5): "PromiseAllResolveElementSharedFun",
+  ("old_space", 0x058e9): "PromiseAllSettledResolveElementSharedFun",
+  ("old_space", 0x0590d): "PromiseAllSettledRejectElementSharedFun",
+  ("old_space", 0x05931): "PromiseAnyRejectElementSharedFun",
+  ("old_space", 0x05955): "PromiseCapabilityDefaultRejectSharedFun",
+  ("old_space", 0x05979): "PromiseCapabilityDefaultResolveSharedFun",
+  ("old_space", 0x0599d): "PromiseCatchFinallySharedFun",
+  ("old_space", 0x059c1): "PromiseGetCapabilitiesExecutorSharedFun",
+  ("old_space", 0x059e5): "PromiseThenFinallySharedFun",
+  ("old_space", 0x05a09): "PromiseThrowerFinallySharedFun",
+  ("old_space", 0x05a2d): "PromiseValueThunkFinallySharedFun",
+  ("old_space", 0x05a51): "ProxyRevokeSharedFun",
+  ("old_space", 0x05a75): "ShadowRealmImportValueFulfilledSFI",
+  ("old_space", 0x05a99): "SourceTextModuleExecuteAsyncModuleFulfilledSFI",
+  ("old_space", 0x05abd): "SourceTextModuleExecuteAsyncModuleRejectedSFI",
 }
 
 # Lower 32 bits of first page addresses for various heap spaces.