deps/v8/src/builtins/array-flat.tq - main - githubmirror/node

deps/v8/src/builtins/array-flat.tq
272 строки10 KB
Michaël Zasso
deps: update V8 to 12.2.281.27
31 мар 2024, 16:36
31 мар 2024, 16:3609a8440
// Copyright 2023 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 ArrayIsArray_Inline(
    implicit context: Context)(element: JSAny): Boolean {
  if (Is<JSArray>(element)) {
    return True;
  } else if (Is<JSProxy>(element)) {
    return Cast<Boolean>(runtime::ArrayIsArray(element))
        otherwise unreachable;
  } else {
    return False;
  }
}

transitioning macro FlattenIntoArrayFast(
    implicit context: Context)(target: JSReceiver, source: JSReceiver,
    sourceLength: Number, start: Number, depth: Smi, hasMapper: constexpr bool,
    mapfn: JSAny, thisArgs: JSAny): Number
    labels Bailout(Number, Number) {
  // 1. Let targetIndex be start.
  let targetIndex: Number = start;

  // 2. Let sourceIndex be 0.
  let smiSourceIndex: Smi = 0;
  const fastSource = Cast<FastJSArray>(source)
      otherwise goto Bailout(targetIndex, smiSourceIndex);
  let fastOW = NewFastJSArrayWitness(fastSource);

  // The source is a FastJSArray, thus its length must be a Smi.
  dcheck(Is<Smi>(sourceLength));
  const smiSourceLength = UnsafeCast<Smi>(sourceLength);

  // 3. Repeat, while sourceIndex < sourceLen
  for (; smiSourceIndex < smiSourceLength; smiSourceIndex++) {
    fastOW.Recheck() otherwise goto Bailout(targetIndex, smiSourceIndex);

    // Ensure that we haven't walked beyond a possibly updated length.
    if (smiSourceIndex >= fastOW.Get().length)
      goto Bailout(targetIndex, smiSourceIndex);

    // a. Let P be ! ToString(sourceIndex).
    // b. Let exists be ? HasProperty(source, P).
    //   i. Let element be ? Get(source, P).
    let element = fastOW.LoadElementNoHole(smiSourceIndex)
        otherwise continue;
    //   ii. If mapperFunction is present, then
    if constexpr (hasMapper) {
      //  1. Set element to ? Call(mapperFunction, thisArgs , « element,
      //                          sourceIndex, source »).
      element = Call(context, mapfn, thisArgs, element, smiSourceIndex, source);
    }
    // iii. Let shouldFlatten be false.
    let shouldFlatten: Boolean = False;
    // iv. If depth > 0, then
    let elementLength: Number = 0;
    if (depth > 0) {
      // Set shouldFlatten to ? IsArray(element).
      // 1. Let elementLen be ? ToLength(? Get(element, "length")).
      try {
        const elementJSArray: JSArray =
            Cast<JSArray>(element) otherwise NonJSArray;
        shouldFlatten = True;
        elementLength = elementJSArray.length;
      } label NonJSArray {
        if (Is<JSProxy>(element)) {
          shouldFlatten = Cast<Boolean>(runtime::ArrayIsArray(element))
              otherwise unreachable;
        }
        if (shouldFlatten == True) {
          elementLength = GetLengthProperty(element);
        }
      }
    }
    // v. If shouldFlatten is true, then
    if (shouldFlatten == True) {
      if (elementLength > 0) {
        // 2. Set targetIndex to ? FlattenIntoArray(target, element,
        //    elementLen, targetIndex, depth - 1).
        const element = Cast<JSReceiver>(element) otherwise unreachable;
        targetIndex = FlattenIntoArrayWithoutMapFn(
            target, element, elementLength, targetIndex, depth - 1);
      }
    } else {
      // 1. If targetIndex >= 2^53-1, throw a TypeError exception.
      if (targetIndex >= kMaxSafeInteger) deferred {
          ThrowTypeError(
              MessageTemplate::kFlattenPastSafeLength, sourceLength,
              targetIndex);
        }
      // 2. Perform ? CreateDataPropertyOrThrow(target,
      //                                        ! ToString(targetIndex),
      //                                        element).
      FastCreateDataProperty(target, targetIndex, element);
      targetIndex++;
    }
  }
  return targetIndex;
}

// https://tc39.github.io/proposal-flatMap/#sec-FlattenIntoArray
transitioning macro FlattenIntoArraySlow(
    implicit context: Context)(target: JSReceiver, source: JSReceiver,
    sourceIndex: Number, sourceLength: Number, start: Number, depth: Smi,
    hasMapper: constexpr bool, mapfn: JSAny, thisArgs: JSAny): Number {
  // 1. Let targetIndex be start.
  let targetIndex: Number = start;

  // 2. Let sourceIndex be 0.
  let sourceIndex: Number = sourceIndex;

  // 3. Repeat, while sourceIndex < sourceLen
  while (sourceIndex < sourceLength) {
    // a. Let P be ! ToString(sourceIndex).
    // b. Let exists be ? HasProperty(source, P).
    const exists: Boolean = HasProperty(source, sourceIndex);
    if (exists == True) {
      let element: JSAny;
      // i. Let element be ? Get(source, P).
      element = GetProperty(source, sourceIndex);

      // ii. If mapperFunction is present, then
      if constexpr (hasMapper) {
        // 1. Set element to ? Call(mapperFunction, thisArgs , « element,
        //                          sourceIndex, source »).
        element = Call(context, mapfn, thisArgs, element, sourceIndex, source);
      }
      // iii. Let shouldFlatten be false.
      let shouldFlatten: Boolean = False;
      // iv. If depth > 0, then
      if (depth > 0) {
        // Set shouldFlatten to ? IsArray(element).
        shouldFlatten = ArrayIsArray_Inline(element);
      }
      // v. If shouldFlatten is true, then
      if (shouldFlatten == True) {
        // 1. Let elementLen be ? ToLength(? Get(element, "length")).
        const elementLength: Number = GetLengthProperty(element);
        // 2. Set targetIndex to ? FlattenIntoArray(target, element,
        //    elementLen, targetIndex, depth - 1).
        const element = Cast<JSReceiver>(element) otherwise unreachable;
        targetIndex = FlattenIntoArrayWithoutMapFn(
            target, element, elementLength, targetIndex, depth - 1);
      } else {
        // 1. If targetIndex >= 2^53-1, throw a TypeError exception.
        if (targetIndex >= kMaxSafeInteger) deferred {
            ThrowTypeError(
                MessageTemplate::kFlattenPastSafeLength, sourceLength,
                targetIndex);
          }
        // 2. Perform ? CreateDataPropertyOrThrow(target,
        //                                        ! ToString(targetIndex),
        //                                        element).
        FastCreateDataProperty(target, targetIndex, element);
        targetIndex++;
      }
    }
    // d. Increase sourceIndex by 1.
    sourceIndex++;
  }
  return targetIndex;
}

transitioning macro FlattenIntoArray(
    implicit context: Context)(target: JSReceiver, source: JSReceiver,
    sourceLength: Number, start: Number, depth: Smi, hasMapper: constexpr bool,
    mapfn: JSAny, thisArgs: JSAny): Number {
  try {
    return FlattenIntoArrayFast(
        target, source, sourceLength, start, depth, hasMapper, mapfn, thisArgs)
        otherwise Bailout;
  } label Bailout(kTargetIndex: Number, kSourceIndex: Number) {
    return FlattenIntoArraySlow(
        target, source, kSourceIndex, sourceLength, kTargetIndex, depth,
        hasMapper, mapfn, thisArgs);
  }
}

transitioning builtin FlattenIntoArrayWithoutMapFn(
    implicit context: Context)(target: JSReceiver, source: JSReceiver,
    sourceLength: Number, start: Number, depth: Smi): Number {
  // This builtin might get called recursively, check stack for overflow
  // manually as it has stub linkage.
  PerformStackCheck();
  return FlattenIntoArray(
      target, source, sourceLength, start, depth, false, Undefined, Undefined);
}

transitioning builtin FlattenIntoArrayWithMapFn(
    implicit context: Context)(target: JSReceiver, source: JSReceiver,
    sourceLength: Number, start: Number, depth: Smi, mapfn: JSAny,
    thisArgs: JSAny): Number {
  return FlattenIntoArray(
      target, source, sourceLength, start, depth, true, mapfn, thisArgs);
}

// https://tc39.github.io/proposal-flatMap/#sec-Array.prototype.flat
transitioning javascript builtin ArrayPrototypeFlat(
    js-implicit context: NativeContext, receiver: JSAny)(...arguments): JSAny {
  // 1. Let O be ? ToObject(this value).
  const o: JSReceiver = ToObject_Inline(context, receiver);

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

  // 3. Let depthNum be 1.
  let depthNum: Number = 1;

  // 4. If depth is not Undefined, then
  if (arguments[0] != Undefined) {
    // a. Set depthNum to ? ToInteger(depth).
    depthNum = ToInteger_Inline(arguments[0]);
  }

  // We will hit stack overflow before the stack depth reaches kSmiMax, so we
  // can truncate depthNum(Number) to Smi to improve performance.
  let depthSmi: Smi = 0;
  try {
    depthSmi = Cast<PositiveSmi>(depthNum) otherwise NotPositiveSmi;
  } label NotPositiveSmi {
    if (depthNum <= 0) {
      depthSmi = 0;
    } else {
      depthSmi = Convert<Smi>(Convert<intptr>(kSmiMax));
    }
  }

  // 5. Let A be ? ArraySpeciesCreate(O, 0).
  const a: JSReceiver = ArraySpeciesCreate(context, o, 0);

  // 6. Perform ? FlattenIntoArray(A, O, sourceLen, 0, depthNum).
  FlattenIntoArrayWithoutMapFn(a, o, len, 0, depthSmi);

  // 7. Return A.
  return a;
}

// https://tc39.github.io/proposal-flatMap/#sec-Array.prototype.flatMap
transitioning javascript builtin ArrayPrototypeFlatMap(
    js-implicit context: NativeContext, receiver: JSAny)(...arguments): JSAny {
  // 1. Let O be ? ToObject(this value).
  const o: JSReceiver = ToObject_Inline(context, receiver);

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

  // 3. If IsCallable(mapperFunction) is false, throw a TypeError exception.
  let mapfn: Callable;
  try {
    mapfn = Cast<Callable>(arguments[0])
        otherwise NonCallableError;
  } label NonCallableError deferred {
    ThrowCalledNonCallable(arguments[0]);
  }


  // 4. If thisArgs is present, let T be thisArgs; else let T be Undefined.
  const t: JSAny = arguments[1];

  // 5. Let A be ? ArraySpeciesCreate(O, 0).
  const a: JSReceiver = ArraySpeciesCreate(context, o, 0);

  // 6. Perform ? FlattenIntoArray(A, O, sourceLen, 0, depthNum).
  FlattenIntoArrayWithMapFn(a, o, len, 0, 1, mapfn, t);

  // 7. Return A.
  return a;
}
}