src/builtins/array.tq

// 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.

#include 'src/builtins/builtins-array-gen.h'

namespace array {
  // Naming convention from elements.cc. We have a similar intent but implement
  // fastpaths using generics instead of using a class hierarchy for elements
  // kinds specific implementations.
  type GenericElementsAccessor;
  type FastPackedSmiElements;
  type FastPackedObjectElements;
  type FastPackedDoubleElements;
  type FastSmiOrObjectElements;
  type FastDoubleElements;
  type DictionaryElements;

  macro EnsureWriteableFastElements(implicit context: Context)(array: JSArray) {
    assert(IsFastElementsKind(array.map.elements_kind));

    const elements: FixedArrayBase = array.elements;
    if (elements.map != kCOWMap) return;

    // There are no COW *_DOUBLE_ELEMENTS arrays, so we are allowed to always
    // extract FixedArrays and don't have to worry about FixedDoubleArrays.
    assert(IsFastSmiOrTaggedElementsKind(array.map.elements_kind));

    const length: Smi = Cast<Smi>(array.length) otherwise unreachable;
    array.elements =
        ExtractFixedArray(elements, 0, length, length, kFixedArrays);
    assert(array.elements.map != kCOWMap);
  }

  macro LoadElementOrUndefined(implicit context:
                                   Context)(a: FixedArray, i: Smi): JSAny {
    const e = UnsafeCast<(JSAny | TheHole)>(a.objects[i]);
    return ReplaceTheHoleWithUndefined(e);
  }

  macro LoadElementOrUndefined(a: FixedDoubleArray, i: Smi): NumberOrUndefined {
    const f: float64 = LoadDoubleWithHoleCheck(a, i) otherwise return Undefined;
    return AllocateHeapNumberWithValue(f);
  }

  macro StoreArrayHole(elements: FixedDoubleArray, k: Smi): void {
    StoreFixedDoubleArrayHoleSmi(elements, k);
  }

  macro StoreArrayHole(elements: FixedArray, k: Smi): void {
    elements.objects[k] = TheHole;
  }

  extern macro SetPropertyLength(implicit context: Context)(JSAny, Number);
}