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// Copyright 2017 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-iterator-gen.h"
#include "src/builtins/growable-fixed-array-gen.h"
#include "src/builtins/builtins-collections-gen.h"
#include "src/builtins/builtins-string-gen.h"
#include "src/builtins/builtins-utils-gen.h"
#include "src/builtins/builtins.h"
#include "src/codegen/code-stub-assembler.h"
#include "src/heap/factory-inl.h"
namespace v8 {
namespace internal {
using IteratorRecord = TorqueStructIteratorRecord;
TNode<Object> IteratorBuiltinsAssembler::GetIteratorMethod(
TNode<Context> context, TNode<Object> object) {
return GetProperty(context, object, factory()->iterator_symbol());
}
IteratorRecord IteratorBuiltinsAssembler::GetIterator(TNode<Context> context,
TNode<Object> object) {
TNode<Object> method = GetIteratorMethod(context, object);
return GetIterator(context, object, method);
}
IteratorRecord IteratorBuiltinsAssembler::GetIterator(TNode<Context> context,
TNode<Object> object,
TNode<Object> method) {
Label if_not_callable(this, Label::kDeferred), if_callable(this);
GotoIf(TaggedIsSmi(method), &if_not_callable);
Branch(IsCallable(CAST(method)), &if_callable, &if_not_callable);
BIND(&if_not_callable);
CallRuntime(Runtime::kThrowIteratorError, context, object);
Unreachable();
BIND(&if_callable);
{
TNode<Object> iterator = Call(context, method, object);
Label get_next(this), if_notobject(this, Label::kDeferred);
GotoIf(TaggedIsSmi(iterator), &if_notobject);
Branch(IsJSReceiver(CAST(iterator)), &get_next, &if_notobject);
BIND(&if_notobject);
CallRuntime(Runtime::kThrowSymbolIteratorInvalid, context);
Unreachable();
BIND(&get_next);
TNode<Object> next =
GetProperty(context, iterator, factory()->next_string());
return IteratorRecord{TNode<JSReceiver>::UncheckedCast(iterator), next};
}
}
TNode<JSReceiver> IteratorBuiltinsAssembler::IteratorStep(
TNode<Context> context, const IteratorRecord& iterator, Label* if_done,
base::Optional<TNode<Map>> fast_iterator_result_map) {
DCHECK_NOT_NULL(if_done);
// 1. a. Let result be ? Invoke(iterator, "next", « »).
TNode<Object> result = Call(context, iterator.next, iterator.object);
// 3. If Type(result) is not Object, throw a TypeError exception.
Label if_notobject(this, Label::kDeferred), return_result(this);
GotoIf(TaggedIsSmi(result), &if_notobject);
TNode<HeapObject> heap_object_result = CAST(result);
TNode<Map> result_map = LoadMap(heap_object_result);
if (fast_iterator_result_map) {
// Fast iterator result case:
Label if_generic(this);
// 4. Return result.
GotoIfNot(TaggedEqual(result_map, *fast_iterator_result_map), &if_generic);
// IteratorComplete
// 2. Return ToBoolean(? Get(iterResult, "done")).
TNode<Object> done =
LoadObjectField(heap_object_result, JSIteratorResult::kDoneOffset);
BranchIfToBooleanIsTrue(done, if_done, &return_result);
BIND(&if_generic);
}
// Generic iterator result case:
{
// 3. If Type(result) is not Object, throw a TypeError exception.
GotoIfNot(IsJSReceiverMap(result_map), &if_notobject);
// IteratorComplete
// 2. Return ToBoolean(? Get(iterResult, "done")).
TNode<Object> done =
GetProperty(context, heap_object_result, factory()->done_string());
BranchIfToBooleanIsTrue(done, if_done, &return_result);
}
BIND(&if_notobject);
CallRuntime(Runtime::kThrowIteratorResultNotAnObject, context, result);
Unreachable();
BIND(&return_result);
return CAST(heap_object_result);
}
TNode<Object> IteratorBuiltinsAssembler::IteratorValue(
TNode<Context> context, TNode<JSReceiver> result,
base::Optional<TNode<Map>> fast_iterator_result_map) {
Label exit(this);
TVARIABLE(Object, var_value);
if (fast_iterator_result_map) {
// Fast iterator result case:
Label if_generic(this);
TNode<Map> map = LoadMap(result);
GotoIfNot(TaggedEqual(map, *fast_iterator_result_map), &if_generic);
var_value = LoadObjectField(result, JSIteratorResult::kValueOffset);
Goto(&exit);
BIND(&if_generic);
}
// Generic iterator result case:
var_value = GetProperty(context, result, factory()->value_string());
Goto(&exit);
BIND(&exit);
return var_value.value();
}
TNode<JSArray> IteratorBuiltinsAssembler::IterableToList(
TNode<Context> context, TNode<Object> iterable, TNode<Object> iterator_fn) {
GrowableFixedArray values(state());
FillFixedArrayFromIterable(context, iterable, iterator_fn, &values);
return values.ToJSArray(context);
}
TNode<FixedArray> IteratorBuiltinsAssembler::IterableToFixedArray(
TNode<Context> context, TNode<Object> iterable, TNode<Object> iterator_fn) {
GrowableFixedArray values(state());
FillFixedArrayFromIterable(context, iterable, iterator_fn, &values);
TNode<FixedArray> new_array = values.ToFixedArray();
return new_array;
}
void IteratorBuiltinsAssembler::FillFixedArrayFromIterable(
TNode<Context> context, TNode<Object> iterable, TNode<Object> iterator_fn,
GrowableFixedArray* values) {
// 1. Let iteratorRecord be ? GetIterator(items, method).
IteratorRecord iterator_record = GetIterator(context, iterable, iterator_fn);
// 2. Let values be a new empty List.
// The GrowableFixedArray has already been created. It's ok if we do this step
// out of order, since creating an empty List is not observable.
Label loop_start(this, {values->var_array(), values->var_length(),
values->var_capacity()}),
done(this);
Goto(&loop_start);
// 3. Let next be true.
// 4. Repeat, while next is not false
BIND(&loop_start);
{
// a. Set next to ? IteratorStep(iteratorRecord).
TNode<JSReceiver> next = IteratorStep(context, iterator_record, &done);
// b. If next is not false, then
// i. Let nextValue be ? IteratorValue(next).
TNode<Object> next_value = IteratorValue(context, next);
// ii. Append nextValue to the end of the List values.
values->Push(next_value);
Goto(&loop_start);
}
BIND(&done);
}
TF_BUILTIN(IterableToList, IteratorBuiltinsAssembler) {
auto context = Parameter<Context>(Descriptor::kContext);
auto iterable = Parameter<Object>(Descriptor::kIterable);
auto iterator_fn = Parameter<Object>(Descriptor::kIteratorFn);
Return(IterableToList(context, iterable, iterator_fn));
}
TF_BUILTIN(IterableToFixedArray, IteratorBuiltinsAssembler) {
auto context = Parameter<Context>(Descriptor::kContext);
auto iterable = Parameter<Object>(Descriptor::kIterable);
auto iterator_fn = Parameter<Object>(Descriptor::kIteratorFn);
Return(IterableToFixedArray(context, iterable, iterator_fn));
}
#if V8_ENABLE_WEBASSEMBLY
TF_BUILTIN(IterableToFixedArrayForWasm, IteratorBuiltinsAssembler) {
auto context = Parameter<Context>(Descriptor::kContext);
auto iterable = Parameter<Object>(Descriptor::kIterable);
auto expected_length = Parameter<Smi>(Descriptor::kExpectedLength);
TNode<Object> iterator_fn = GetIteratorMethod(context, iterable);
GrowableFixedArray values(state());
Label done(this);
FillFixedArrayFromIterable(context, iterable, iterator_fn, &values);
GotoIf(WordEqual(SmiUntag(expected_length), values.var_length()->value()),
&done);
Return(CallRuntime(
Runtime::kThrowTypeError, context,
SmiConstant(MessageTemplate::kWasmTrapMultiReturnLengthMismatch)));
BIND(&done);
Return(values.var_array()->value());
}
#endif // V8_ENABLE_WEBASSEMBLY
TNode<JSArray> IteratorBuiltinsAssembler::StringListFromIterable(
TNode<Context> context, TNode<Object> iterable) {
Label done(this);
GrowableFixedArray list(state());
// 1. If iterable is undefined, then
// a. Return a new empty List.
GotoIf(IsUndefined(iterable), &done);
// 2. Let iteratorRecord be ? GetIterator(items).
IteratorRecord iterator_record = GetIterator(context, iterable);
// 3. Let list be a new empty List.
Label loop_start(this,
{list.var_array(), list.var_length(), list.var_capacity()});
Goto(&loop_start);
// 4. Let next be true.
// 5. Repeat, while next is not false
Label if_isnotstringtype(this, Label::kDeferred),
if_exception(this, Label::kDeferred);
BIND(&loop_start);
{
// a. Set next to ? IteratorStep(iteratorRecord).
TNode<JSReceiver> next = IteratorStep(context, iterator_record, &done);
// b. If next is not false, then
// i. Let nextValue be ? IteratorValue(next).
TNode<Object> next_value = IteratorValue(context, next);
// ii. If Type(nextValue) is not String, then
GotoIf(TaggedIsSmi(next_value), &if_isnotstringtype);
TNode<Uint16T> next_value_type = LoadInstanceType(CAST(next_value));
GotoIfNot(IsStringInstanceType(next_value_type), &if_isnotstringtype);
// iii. Append nextValue to the end of the List list.
list.Push(next_value);
Goto(&loop_start);
// 5.b.ii
BIND(&if_isnotstringtype);
{
// 1. Let error be ThrowCompletion(a newly created TypeError object).
TVARIABLE(Object, var_exception);
{
compiler::ScopedExceptionHandler handler(this, &if_exception,
&var_exception);
CallRuntime(Runtime::kThrowTypeError, context,
SmiConstant(MessageTemplate::kIterableYieldedNonString),
next_value);
}
Unreachable();
// 2. Return ? IteratorClose(iteratorRecord, error).
BIND(&if_exception);
IteratorCloseOnException(context, iterator_record);
CallRuntime(Runtime::kReThrow, context, var_exception.value());
Unreachable();
}
}
BIND(&done);
// 6. Return list.
return list.ToJSArray(context);
}
TF_BUILTIN(StringListFromIterable, IteratorBuiltinsAssembler) {
auto context = Parameter<Context>(Descriptor::kContext);
auto iterable = Parameter<Object>(Descriptor::kIterable);
Return(StringListFromIterable(context, iterable));
}
// This builtin always returns a new JSArray and is thus safe to use even in the
// presence of code that may call back into user-JS. This builtin will take the
// fast path if the iterable is a fast array and the Array prototype and the
// Symbol.iterator is untouched. The fast path skips the iterator and copies the
// backing store to the new array. Note that if the array has holes, the holes
// will be copied to the new array, which is inconsistent with the behavior of
// an actual iteration, where holes should be replaced with undefined (if the
// prototype has no elements). To maintain the correct behavior for holey
// arrays, use the builtins IterableToList or IterableToListWithSymbolLookup.
TF_BUILTIN(IterableToListMayPreserveHoles, IteratorBuiltinsAssembler) {
auto context = Parameter<Context>(Descriptor::kContext);
auto iterable = Parameter<Object>(Descriptor::kIterable);
auto iterator_fn = Parameter<Object>(Descriptor::kIteratorFn);
Label slow_path(this);
GotoIfNot(IsFastJSArrayWithNoCustomIteration(context, iterable), &slow_path);
// The fast path will copy holes to the new array.
TailCallBuiltin(Builtin::kCloneFastJSArray, context, iterable);
BIND(&slow_path);
TailCallBuiltin(Builtin::kIterableToList, context, iterable, iterator_fn);
}
void IteratorBuiltinsAssembler::FastIterableToList(
TNode<Context> context, TNode<Object> iterable,
TVariable<JSArray>* var_result, Label* slow) {
Label done(this), check_string(this), check_map(this), check_set(this);
GotoIfNot(
Word32Or(IsFastJSArrayWithNoCustomIteration(context, iterable),
IsFastJSArrayForReadWithNoCustomIteration(context, iterable)),
&check_string);
// Fast path for fast JSArray.
*var_result = CAST(
CallBuiltin(Builtin::kCloneFastJSArrayFillingHoles, context, iterable));
Goto(&done);
BIND(&check_string);
{
Label string_maybe_fast_call(this);
StringBuiltinsAssembler string_assembler(state());
string_assembler.BranchIfStringPrimitiveWithNoCustomIteration(
iterable, context, &string_maybe_fast_call, &check_map);
BIND(&string_maybe_fast_call);
const TNode<IntPtrT> length = LoadStringLengthAsWord(CAST(iterable));
// Use string length as conservative approximation of number of codepoints.
GotoIf(
IntPtrGreaterThan(length, IntPtrConstant(JSArray::kMaxFastArrayLength)),
slow);
*var_result = CAST(CallBuiltin(Builtin::kStringToList, context, iterable));
Goto(&done);
}
BIND(&check_map);
{
Label map_fast_call(this);
BranchIfIterableWithOriginalKeyOrValueMapIterator(
state(), iterable, context, &map_fast_call, &check_set);
BIND(&map_fast_call);
*var_result =
CAST(CallBuiltin(Builtin::kMapIteratorToList, context, iterable));
Goto(&done);
}
BIND(&check_set);
{
Label set_fast_call(this);
BranchIfIterableWithOriginalValueSetIterator(state(), iterable, context,
&set_fast_call, slow);
BIND(&set_fast_call);
*var_result =
CAST(CallBuiltin(Builtin::kSetOrSetIteratorToList, context, iterable));
Goto(&done);
}
BIND(&done);
}
TNode<JSArray> IteratorBuiltinsAssembler::FastIterableToList(
TNode<Context> context, TNode<Object> iterable, Label* slow) {
TVARIABLE(JSArray, var_fast_result);
FastIterableToList(context, iterable, &var_fast_result, slow);
return var_fast_result.value();
}
// This builtin loads the property Symbol.iterator as the iterator, and has fast
// paths for fast arrays, for primitive strings, for sets and set iterators, and
// for map iterators. These fast paths will only be taken if Symbol.iterator and
// the Iterator prototype are not modified in a way that changes the original
// iteration behavior.
// * In case of fast holey arrays, holes will be converted to undefined to
// reflect iteration semantics. Note that replacement by undefined is only
// correct when the NoElements protector is valid.
// * In case of map/set iterators, there is an additional requirement that the
// iterator is not partially consumed. To be spec-compliant, after spreading
// the iterator is set to be exhausted.
TF_BUILTIN(IterableToListWithSymbolLookup, IteratorBuiltinsAssembler) {
auto context = Parameter<Context>(Descriptor::kContext);
auto iterable = Parameter<Object>(Descriptor::kIterable);
Label slow_path(this);
GotoIfForceSlowPath(&slow_path);
TVARIABLE(JSArray, var_result);
FastIterableToList(context, iterable, &var_result, &slow_path);
Return(var_result.value());
BIND(&slow_path);
{
TNode<Object> iterator_fn = GetIteratorMethod(context, iterable);
TailCallBuiltin(Builtin::kIterableToList, context, iterable, iterator_fn);
}
}
TF_BUILTIN(GetIteratorWithFeedbackLazyDeoptContinuation,
IteratorBuiltinsAssembler) {
auto context = Parameter<Context>(Descriptor::kContext);
auto receiver = Parameter<Object>(Descriptor::kReceiver);
// TODO(v8:10047): Use TaggedIndex here once TurboFan supports it.
auto call_slot_smi = Parameter<Smi>(Descriptor::kCallSlot);
auto feedback = Parameter<FeedbackVector>(Descriptor::kFeedback);
auto iterator_method = Parameter<Object>(Descriptor::kResult);
// Note, that the builtin also expects the call_slot as a Smi.
TNode<Object> result =
CallBuiltin(Builtin::kCallIteratorWithFeedback, context, receiver,
iterator_method, call_slot_smi, feedback);
Return(result);
}
// This builtin creates a FixedArray based on an Iterable and doesn't have a
// fast path for anything.
TF_BUILTIN(IterableToFixedArrayWithSymbolLookupSlow,
IteratorBuiltinsAssembler) {
auto context = Parameter<Context>(Descriptor::kContext);
auto iterable = Parameter<Object>(Descriptor::kIterable);
TNode<Object> iterator_fn = GetIteratorMethod(context, iterable);
TailCallBuiltin(Builtin::kIterableToFixedArray, context, iterable,
iterator_fn);
}
} // namespace internal
} // namespace v8
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