src/builtins/array.tq - v8/v8.git - Git at Google

 // Copyright 2018 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.

 module array {
   macro GetLengthProperty(context: Context, o: Object): Number {
     if (BranchIfFastJSArray(o, context)) {
       let a: JSArray = unsafe_cast<JSArray>(o);
       return a.length_fast;
     } else
       deferred {
         return ToLength_Inline(context, GetProperty(context, o, 'length'));
       }
   }

   macro FastArraySplice(
       context: Context, args: constexpr Arguments, o: Object,
       originalLengthNumber: Number, actualStartNumber: Number, insertCount: Smi,
       actualDeleteCountNumber: Number): Object
   labels Bailout {
     let originalLength: Smi = cast<Smi>(originalLengthNumber) otherwise Bailout;
     let actualStart: Smi = cast<Smi>(actualStartNumber) otherwise Bailout;
     let actualDeleteCount: Smi =
         cast<Smi>(actualDeleteCountNumber) otherwise Bailout;
     let lengthDelta: Smi = insertCount - actualDeleteCount;
     let newLength: Smi = originalLength + lengthDelta;

     let a: JSArray = cast<JSArray>(o) otherwise Bailout;

     let map: Map = a.map;
     if (!IsPrototypeInitialArrayPrototype(context, map)) goto Bailout;
     if (IsNoElementsProtectorCellInvalid()) goto Bailout;
     if (IsArraySpeciesProtectorCellInvalid()) goto Bailout;

     // Fast path only works on fast elements kind and with writable length.
     let elementsKind: ElementsKind = EnsureArrayPushable(map) otherwise Bailout;
     if (!IsFastElementsKind(elementsKind)) goto Bailout;

     // For now, only support non-double fast elements
     if (!IsFastSmiOrTaggedElementsKind(elementsKind)) goto Bailout;

     if (IsFastSmiElementsKind(elementsKind)) {
       for (let e: Object of args [2: ]) {
         if (TaggedIsNotSmi(e)) goto Bailout;
       }
     }

     // Make sure that the length hasn't been changed by side-effect.
     let length: Smi = cast<Smi>(a.length) otherwise Bailout;
     if (originalLength != length) goto Bailout;

     let deletedResult: JSArray =
         ExtractFastJSArray(context, a, actualStart, actualDeleteCount);

     if (newLength == 0) {
       a.elements = kEmptyFixedArray;
       a.length = 0;
       return deletedResult;
     }

     let elements: FixedArray = cast<FixedArray>(a.elements) otherwise Bailout;
     let elementsMap: Map = elements.map;

     // If the source is a COW array or the spliced array is larger then the
     // source array, then allocate a new FixedArray to hold the result.
     let newElements: FixedArray = elements;
     if ((elementsMap == kCOWMap) || (lengthDelta > 0)) {
       newElements = ExtractFixedArray(
           elements, 0, actualStart, newLength, kAllFixedArrays);
       newElements.map = elementsMap;
       a.elements = newElements;
     }

     // Double check that the array is still in fast elements mode
     assert(IsFastSmiElementsKind(a.map.elements_kind));

     // Copy over inserted elements.
     let k: Smi = actualStart;
     if (insertCount > 0) {
       for (let e: Object of args [2: ]) {
         newElements[k++] = e;
       }
     }

     // Copy over elements after deleted elements.
     let count: Smi = length - actualStart - actualDeleteCount;
     while (count > 0) {
       let e: Object = elements[k - lengthDelta];
       newElements[k++] = e;
       count--;
     }

     // Fill rest of spliced FixedArray with the hole, but only if the
     // destination FixedArray is the original array's, since otherwise the array
     // is pre-filled with holes.
     if (elements == newElements) {
       let limit: Smi = elements.length;
       while (k < limit) {
         newElements[k++] = Hole;
       }
     }

     // Update the array's length after all the FixedArray shuffling is done.
     a.length = newLength;

     return deletedResult;
   }

   // https://tc39.github.io/ecma262/#sec-array.prototype.splice
   javascript builtin ArraySpliceTorque(
       context: Context, receiver: Object, ...arguments): Object {
     // 1. Let O be ? ToObject(this value).
     let o: JSReceiver = ToObject(context, receiver);

     // 2. Let len be ? ToLength(? Get(O, "length")).
     let len: Number = GetLengthProperty(context, o);

     // 3. Let relativeStart be ? ToInteger(start).
     let start: Object = arguments[0];
     let relativeStart: Number = ToInteger_Inline(context, start);

     // 4. If relativeStart < 0, let actualStart be max((len + relativeStart),
     // 0);
     //    else let actualStart be min(relativeStart, len).
     let actualStart: Number = relativeStart < 0 ?
         max((len + relativeStart), 0) :
         min(relativeStart, len);

     let insertCount: Smi;
     let actualDeleteCount: Number;
     // 5. If the Number of actual arguments is 0, then
     if (arguments.length == 0) {
       // a. Let insertCount be 0.
       insertCount = 0;
       // b. Let actualDeleteCount be 0.
       actualDeleteCount = 0;
       // 6. Else if the Number of actual arguments is 1, then
     } else if (arguments.length == 1) {
       // a. Let insertCount be 0.
       insertCount = 0;
       // b. Let actualDeleteCount be len - actualStart.
       actualDeleteCount = len - actualStart;
       // 7. Else,
     } else {
       // a. Let insertCount be the Number of actual arguments minus 2.
       insertCount = convert<Smi>(arguments.length) - 2;
       // b. Let dc be ? ToInteger(deleteCount).
       let deleteCount: Object = arguments[1];
       let dc: Number = ToInteger_Inline(context, deleteCount);
       // c. Let actualDeleteCount be min(max(dc, 0), len - actualStart).
       actualDeleteCount = min(max(dc, 0), len - actualStart);
     }

     // 8. If len + insertCount - actualDeleteCount > 2^53-1, throw a
     //    Bailout exception.
     if (len + insertCount - actualDeleteCount > kMaxSafeInteger) {
       ThrowRangeError(context, kInvalidArrayLength);
     }

     try {
       return FastArraySplice(
           context, arguments, o, len, actualStart, insertCount,
           actualDeleteCount) otherwise Bailout;
     }
     label Bailout {}
     // If the fast case fails, just continue with the slow, correct,
     // spec-compliant case.

     // 9. Let A be ? ArraySpeciesCreate(O, actualDeleteCount).
     let a: Object = ArraySpeciesCreate(context, o, actualDeleteCount);

     // 10. Let k be 0.
     let k: Number = 0;

     // 11. Repeat, while k < actualDeleteCount
     while (k < actualDeleteCount) {
       // a. Let from be ! ToString(actualStart + k).
       let from: String = ToString_Inline(context, actualStart + k);

       // b. Let fromPresent be ? HasProperty(O, from).
       let fromPresent: Oddball = HasProperty(context, o, from);

       // c. If fromPresent is true, then
       if (fromPresent == True) {
         // i. Let fromValue be ? Get(O, from).
         let fromValue: Object = GetProperty(context, o, from);

         // ii. Perform ? CreateDataPropertyOrThrow(A, ! ToString(k), fromValue).
         CreateDataProperty(context, a, ToString_Inline(context, k), fromValue);
       }

       // d. Increment k by 1.
       k = k + 1;
     }

     // 12. Perform ? Set(A, "length", actualDeleteCount, true).
     SetProperty(context, a, 'length', actualDeleteCount);

     // 13. Let items be a List whose elements are, in left-to-right order,
     //     the portion of the actual argument list starting with the third
     //     argument. The list is empty if fewer than three arguments were
     //     passed.
     // 14. Let itemCount be the Number of elements in items.
     let itemCount: Number = insertCount;

     // 15. If itemCount < actualDeleteCount, then
     if (itemCount < actualDeleteCount) {
       // a. Let k be actualStart.
       let k: Number = actualStart;

       // b. Repeat, while k < (len - actualDeleteCount)
       while (k < (len - actualDeleteCount)) {
         // i. Let from be ! ToString(k + actualDeleteCount).
         let from: String = ToString_Inline(context, k + actualDeleteCount);
         // ii. Let to be ! ToString(k + itemCount).
         let to: String = ToString_Inline(context, k + itemCount);

         // iii. Let fromPresent be ? HasProperty(O, from).
         let fromPresent: Oddball = HasProperty(context, o, from);

         // iv. If fromPresent is true, then
         if (fromPresent == True) {
           // 1. Let fromValue be ? Get(O, from).
           let fromValue: Object = GetProperty(context, o, from);

           // 2. Perform ? Set(O, to, fromValue, true).
           SetProperty(context, o, to, fromValue);

           // v. Else fromPresent is false,
         } else {
           // 1. Perform ? DeletePropertyOrThrow(O, to).
           DeleteProperty(context, o, to, kStrict);
         }
         // vi. Increase k by 1.
         k = k + 1;
       }

       // c. Let k be len.
       k = len;
       // d. Repeat, while k > (len - actualDeleteCount + itemCount)
       while (k > (len - actualDeleteCount + itemCount)) {
         // i. Perform ? DeletePropertyOrThrow(O, ! ToString(k - 1)).
         DeleteProperty(context, o, ToString_Inline(context, k - 1), kStrict);

         // ii. Decrease k by 1.
         k = k - 1;
       }
       // 16. Else if itemCount > actualDeleteCount, then
     } else if (itemCount > actualDeleteCount) {
       // a. Let k be (len - actualDeleteCount).
       let k: Number = len - actualDeleteCount;

       // b. Repeat, while k > actualStart
       while (k > actualStart) {
         // i. Let from be ! ToString(k + actualDeleteCount - 1).
         let from: String = ToString_Inline(context, k + actualDeleteCount - 1);

         // ii. Let to be ! ToString(k + itemCount - 1).
         let to: String = ToString_Inline(context, k + itemCount - 1);

         // iii. Let fromPresent be ? HasProperty(O, from).
         let fromPresent: Oddball = HasProperty(context, o, from);

         // iv. If fromPresent is true, then
         if (fromPresent == True) {
           // 1. Let fromValue be ? Get(O, from).
           let fromValue: Object = GetProperty(context, o, from);

           // 2. Perform ? Set(O, to, fromValue, true).
           SetProperty(context, o, to, fromValue);

           // v. Else fromPresent is false,
         } else {
           // 1. Perform ? DeletePropertyOrThrow(O, to).
           DeleteProperty(context, o, to, kStrict);
         }

         // vi. Decrease k by 1.
         k = k - 1;
       }
     }

     // 17. Let k be actualStart.
     k = actualStart;

     // 18. Repeat, while items is not empty
     //   a. Remove the first element from items and let E be the value of that
     //   element.
     if (arguments.length > 2) {
       for (let e: Object of arguments [2: ]) {
         // b. Perform ? Set(O, ! ToString(k), E, true).
         SetProperty(context, o, ToString_Inline(context, k), e);

         // c. Increase k by 1.
         k = k + 1;
       }
     }

     // 19. Perform ? Set(O, "length", len - actualDeleteCount + itemCount,
     // true).
     SetProperty(context, o, 'length', len - actualDeleteCount + itemCount);

     return a;
   }
 }
	// Copyright 2018 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.

	module array {
	macro GetLengthProperty(context: Context, o: Object): Number {
	if (BranchIfFastJSArray(o, context)) {
	let a: JSArray = unsafe_cast<JSArray>(o);
	return a.length_fast;
	} else
	deferred {
	return ToLength_Inline(context, GetProperty(context, o, 'length'));
	}
	}

	macro FastArraySplice(
	context: Context, args: constexpr Arguments, o: Object,
	originalLengthNumber: Number, actualStartNumber: Number, insertCount: Smi,
	actualDeleteCountNumber: Number): Object
	labels Bailout {
	let originalLength: Smi = cast<Smi>(originalLengthNumber) otherwise Bailout;
	let actualStart: Smi = cast<Smi>(actualStartNumber) otherwise Bailout;
	let actualDeleteCount: Smi =
	cast<Smi>(actualDeleteCountNumber) otherwise Bailout;
	let lengthDelta: Smi = insertCount - actualDeleteCount;
	let newLength: Smi = originalLength + lengthDelta;

	let a: JSArray = cast<JSArray>(o) otherwise Bailout;

	let map: Map = a.map;
	if (!IsPrototypeInitialArrayPrototype(context, map)) goto Bailout;
	if (IsNoElementsProtectorCellInvalid()) goto Bailout;
	if (IsArraySpeciesProtectorCellInvalid()) goto Bailout;

	// Fast path only works on fast elements kind and with writable length.
	let elementsKind: ElementsKind = EnsureArrayPushable(map) otherwise Bailout;
	if (!IsFastElementsKind(elementsKind)) goto Bailout;

	// For now, only support non-double fast elements
	if (!IsFastSmiOrTaggedElementsKind(elementsKind)) goto Bailout;

	if (IsFastSmiElementsKind(elementsKind)) {
	for (let e: Object of args [2: ]) {
	if (TaggedIsNotSmi(e)) goto Bailout;
	}
	}

	// Make sure that the length hasn't been changed by side-effect.
	let length: Smi = cast<Smi>(a.length) otherwise Bailout;
	if (originalLength != length) goto Bailout;

	let deletedResult: JSArray =
	ExtractFastJSArray(context, a, actualStart, actualDeleteCount);

	if (newLength == 0) {
	a.elements = kEmptyFixedArray;
	a.length = 0;
	return deletedResult;
	}

	let elements: FixedArray = cast<FixedArray>(a.elements) otherwise Bailout;
	let elementsMap: Map = elements.map;

	// If the source is a COW array or the spliced array is larger then the
	// source array, then allocate a new FixedArray to hold the result.
	let newElements: FixedArray = elements;
	if ((elementsMap == kCOWMap) \|\| (lengthDelta > 0)) {
	newElements = ExtractFixedArray(
	elements, 0, actualStart, newLength, kAllFixedArrays);
	newElements.map = elementsMap;
	a.elements = newElements;
	}

	// Double check that the array is still in fast elements mode
	assert(IsFastSmiElementsKind(a.map.elements_kind));

	// Copy over inserted elements.
	let k: Smi = actualStart;
	if (insertCount > 0) {
	for (let e: Object of args [2: ]) {
	newElements[k++] = e;
	}
	}

	// Copy over elements after deleted elements.
	let count: Smi = length - actualStart - actualDeleteCount;
	while (count > 0) {
	let e: Object = elements[k - lengthDelta];
	newElements[k++] = e;
	count--;
	}

	// Fill rest of spliced FixedArray with the hole, but only if the
	// destination FixedArray is the original array's, since otherwise the array
	// is pre-filled with holes.
	if (elements == newElements) {
	let limit: Smi = elements.length;
	while (k < limit) {
	newElements[k++] = Hole;
	}
	}

	// Update the array's length after all the FixedArray shuffling is done.
	a.length = newLength;

	return deletedResult;
	}

	// https://tc39.github.io/ecma262/#sec-array.prototype.splice
	javascript builtin ArraySpliceTorque(
	context: Context, receiver: Object, ...arguments): Object {
	// 1. Let O be ? ToObject(this value).
	let o: JSReceiver = ToObject(context, receiver);

	// 2. Let len be ? ToLength(? Get(O, "length")).
	let len: Number = GetLengthProperty(context, o);

	// 3. Let relativeStart be ? ToInteger(start).
	let start: Object = arguments[0];
	let relativeStart: Number = ToInteger_Inline(context, start);

	// 4. If relativeStart < 0, let actualStart be max((len + relativeStart),
	// 0);
	// else let actualStart be min(relativeStart, len).
	let actualStart: Number = relativeStart < 0 ?
	max((len + relativeStart), 0) :
	min(relativeStart, len);

	let insertCount: Smi;
	let actualDeleteCount: Number;
	// 5. If the Number of actual arguments is 0, then
	if (arguments.length == 0) {
	// a. Let insertCount be 0.
	insertCount = 0;
	// b. Let actualDeleteCount be 0.
	actualDeleteCount = 0;
	// 6. Else if the Number of actual arguments is 1, then
	} else if (arguments.length == 1) {
	// a. Let insertCount be 0.
	insertCount = 0;
	// b. Let actualDeleteCount be len - actualStart.
	actualDeleteCount = len - actualStart;
	// 7. Else,
	} else {
	// a. Let insertCount be the Number of actual arguments minus 2.
	insertCount = convert<Smi>(arguments.length) - 2;
	// b. Let dc be ? ToInteger(deleteCount).
	let deleteCount: Object = arguments[1];
	let dc: Number = ToInteger_Inline(context, deleteCount);
	// c. Let actualDeleteCount be min(max(dc, 0), len - actualStart).
	actualDeleteCount = min(max(dc, 0), len - actualStart);
	}

	// 8. If len + insertCount - actualDeleteCount > 2^53-1, throw a
	// Bailout exception.
	if (len + insertCount - actualDeleteCount > kMaxSafeInteger) {
	ThrowRangeError(context, kInvalidArrayLength);
	}

	try {
	return FastArraySplice(
	context, arguments, o, len, actualStart, insertCount,
	actualDeleteCount) otherwise Bailout;
	}
	label Bailout {}
	// If the fast case fails, just continue with the slow, correct,
	// spec-compliant case.

	// 9. Let A be ? ArraySpeciesCreate(O, actualDeleteCount).
	let a: Object = ArraySpeciesCreate(context, o, actualDeleteCount);

	// 10. Let k be 0.
	let k: Number = 0;

	// 11. Repeat, while k < actualDeleteCount
	while (k < actualDeleteCount) {
	// a. Let from be ! ToString(actualStart + k).
	let from: String = ToString_Inline(context, actualStart + k);

	// b. Let fromPresent be ? HasProperty(O, from).
	let fromPresent: Oddball = HasProperty(context, o, from);

	// c. If fromPresent is true, then
	if (fromPresent == True) {
	// i. Let fromValue be ? Get(O, from).
	let fromValue: Object = GetProperty(context, o, from);

	// ii. Perform ? CreateDataPropertyOrThrow(A, ! ToString(k), fromValue).
	CreateDataProperty(context, a, ToString_Inline(context, k), fromValue);
	}

	// d. Increment k by 1.
	k = k + 1;
	}

	// 12. Perform ? Set(A, "length", actualDeleteCount, true).
	SetProperty(context, a, 'length', actualDeleteCount);

	// 13. Let items be a List whose elements are, in left-to-right order,
	// the portion of the actual argument list starting with the third
	// argument. The list is empty if fewer than three arguments were
	// passed.
	// 14. Let itemCount be the Number of elements in items.
	let itemCount: Number = insertCount;

	// 15. If itemCount < actualDeleteCount, then
	if (itemCount < actualDeleteCount) {
	// a. Let k be actualStart.
	let k: Number = actualStart;

	// b. Repeat, while k < (len - actualDeleteCount)
	while (k < (len - actualDeleteCount)) {
	// i. Let from be ! ToString(k + actualDeleteCount).
	let from: String = ToString_Inline(context, k + actualDeleteCount);
	// ii. Let to be ! ToString(k + itemCount).
	let to: String = ToString_Inline(context, k + itemCount);

	// iii. Let fromPresent be ? HasProperty(O, from).
	let fromPresent: Oddball = HasProperty(context, o, from);

	// iv. If fromPresent is true, then
	if (fromPresent == True) {
	// 1. Let fromValue be ? Get(O, from).
	let fromValue: Object = GetProperty(context, o, from);

	// 2. Perform ? Set(O, to, fromValue, true).
	SetProperty(context, o, to, fromValue);

	// v. Else fromPresent is false,
	} else {
	// 1. Perform ? DeletePropertyOrThrow(O, to).
	DeleteProperty(context, o, to, kStrict);
	}
	// vi. Increase k by 1.
	k = k + 1;
	}

	// c. Let k be len.
	k = len;
	// d. Repeat, while k > (len - actualDeleteCount + itemCount)
	while (k > (len - actualDeleteCount + itemCount)) {
	// i. Perform ? DeletePropertyOrThrow(O, ! ToString(k - 1)).
	DeleteProperty(context, o, ToString_Inline(context, k - 1), kStrict);

	// ii. Decrease k by 1.
	k = k - 1;
	}
	// 16. Else if itemCount > actualDeleteCount, then
	} else if (itemCount > actualDeleteCount) {
	// a. Let k be (len - actualDeleteCount).
	let k: Number = len - actualDeleteCount;

	// b. Repeat, while k > actualStart
	while (k > actualStart) {
	// i. Let from be ! ToString(k + actualDeleteCount - 1).
	let from: String = ToString_Inline(context, k + actualDeleteCount - 1);

	// ii. Let to be ! ToString(k + itemCount - 1).
	let to: String = ToString_Inline(context, k + itemCount - 1);

	// iii. Let fromPresent be ? HasProperty(O, from).
	let fromPresent: Oddball = HasProperty(context, o, from);

	// iv. If fromPresent is true, then
	if (fromPresent == True) {
	// 1. Let fromValue be ? Get(O, from).
	let fromValue: Object = GetProperty(context, o, from);

	// 2. Perform ? Set(O, to, fromValue, true).
	SetProperty(context, o, to, fromValue);

	// v. Else fromPresent is false,
	} else {
	// 1. Perform ? DeletePropertyOrThrow(O, to).
	DeleteProperty(context, o, to, kStrict);
	}

	// vi. Decrease k by 1.
	k = k - 1;
	}
	}

	// 17. Let k be actualStart.
	k = actualStart;

	// 18. Repeat, while items is not empty
	// a. Remove the first element from items and let E be the value of that
	// element.
	if (arguments.length > 2) {
	for (let e: Object of arguments [2: ]) {
	// b. Perform ? Set(O, ! ToString(k), E, true).
	SetProperty(context, o, ToString_Inline(context, k), e);

	// c. Increase k by 1.
	k = k + 1;
	}
	}

	// 19. Perform ? Set(O, "length", len - actualDeleteCount + itemCount,
	// true).
	SetProperty(context, o, 'length', len - actualDeleteCount + itemCount);

	return a;
	}
	}