deps/v8/src/heap/factory-base.cc - main - githubmirror/node

deps/v8/src/heap/factory-base.cc
1 542 строки61 KB
Joyee Cheung
build,test: test array index hash collision
24 апр 2026, 19:01
24 апр 2026, 19:01fff9a8a
// Copyright 2020 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/heap/factory-base.h"

#include "src/ast/ast-source-ranges.h"
#include "src/ast/ast.h"
#include "src/common/assert-scope.h"
#include "src/common/globals.h"
#include "src/execution/local-isolate.h"
#include "src/handles/handles-inl.h"
#include "src/heap/factory.h"
#include "src/heap/heap-inl.h"
#include "src/heap/large-page-inl.h"
#include "src/heap/local-factory-inl.h"
#include "src/heap/mutable-page.h"
#include "src/heap/read-only-heap.h"
#include "src/logging/local-logger.h"
#include "src/logging/log.h"
#include "src/objects/arguments-inl.h"
#include "src/objects/instance-type.h"
#include "src/objects/js-regexp-inl.h"
#include "src/objects/literal-objects-inl.h"
#include "src/objects/module-inl.h"
#include "src/objects/oddball.h"
#include "src/objects/shared-function-info-inl.h"
#include "src/objects/shared-function-info.h"
#include "src/objects/source-text-module.h"
#include "src/objects/string-inl.h"
#include "src/objects/string.h"
#include "src/objects/swiss-name-dictionary-inl.h"
#include "src/objects/template-objects-inl.h"
#include "src/roots/roots.h"
#include "src/sandbox/check.h"

namespace v8 {
namespace internal {

template <typename Impl>
template <AllocationType allocation>
Handle<HeapNumber> FactoryBase<Impl>::NewHeapNumber() {
  static_assert(sizeof(HeapNumber) <= kMaxRegularHeapObjectSize);
  Tagged<Map> map = read_only_roots().heap_number_map();
  Tagged<HeapObject> result = AllocateRawWithImmortalMap(
      sizeof(HeapNumber), allocation, map,
      USE_ALLOCATION_ALIGNMENT_HEAP_NUMBER_BOOL ? kDoubleUnaligned
                                                : kTaggedAligned);
  return handle(Cast<HeapNumber>(result), isolate());
}

template V8_EXPORT_PRIVATE Handle<HeapNumber>
FactoryBase<Factory>::NewHeapNumber<AllocationType::kYoung>();
template V8_EXPORT_PRIVATE Handle<HeapNumber>
FactoryBase<Factory>::NewHeapNumber<AllocationType::kOld>();
template V8_EXPORT_PRIVATE Handle<HeapNumber>
FactoryBase<Factory>::NewHeapNumber<AllocationType::kReadOnly>();
template V8_EXPORT_PRIVATE Handle<HeapNumber>
FactoryBase<Factory>::NewHeapNumber<AllocationType::kSharedOld>();

template V8_EXPORT_PRIVATE Handle<HeapNumber>
FactoryBase<LocalFactory>::NewHeapNumber<AllocationType::kOld>();

template <typename Impl>
Handle<Struct> FactoryBase<Impl>::NewStruct(InstanceType type,
                                            AllocationType allocation) {
  ReadOnlyRoots roots = read_only_roots();
  Tagged<Map> map = Map::GetMapFor(roots, type);
  int size = map->instance_size();
  return handle(NewStructInternal(roots, map, size, allocation), isolate());
}

template <typename Impl>
Handle<AccessorPair> FactoryBase<Impl>::NewAccessorPair() {
  auto accessors =
      NewStructInternal<AccessorPair>(ACCESSOR_PAIR_TYPE, AllocationType::kOld);
  DisallowGarbageCollection no_gc;
  accessors->set_getter(read_only_roots().null_value(), SKIP_WRITE_BARRIER);
  accessors->set_setter(read_only_roots().null_value(), SKIP_WRITE_BARRIER);
  return handle(accessors, isolate());
}

template <typename Impl>
Handle<Code> FactoryBase<Impl>::NewCode(const NewCodeOptions& options) {
  DirectHandle<CodeWrapper> wrapper = NewCodeWrapper();
  Tagged<Map> map = read_only_roots().code_map();
  int size = map->instance_size();
  Tagged<Code> code = TrustedCast<Code>(
      AllocateRawWithImmortalMap(size, AllocationType::kTrusted, map));
  DisallowGarbageCollection no_gc;
  code->InitAndPublish(isolate());
  code->initialize_flags(options.kind, options.is_context_specialized,
                         options.is_turbofanned);
  code->set_builtin_id(options.builtin);
  code->set_instruction_size(options.instruction_size);
  code->set_metadata_size(options.metadata_size);
  code->set_inlined_bytecode_size(options.inlined_bytecode_size);
  code->set_osr_offset(options.osr_offset);
  SBXCHECK_IMPLIES(options.deoptimization_data.is_null(),
                   options.osr_offset.IsNone());
  code->set_handler_table_offset(options.handler_table_offset);
  code->set_constant_pool_offset(options.constant_pool_offset);
  code->set_code_comments_offset(options.code_comments_offset);
  code->set_jump_table_info_offset(options.jump_table_info_offset);
  code->set_unwinding_info_offset(options.unwinding_info_offset);
  code->set_parameter_count(options.parameter_count);
  code->set_js_dispatch_handle(kNullJSDispatchHandle);

  // Set bytecode/interpreter data or deoptimization data.
  if (CodeKindUsesBytecodeOrInterpreterData(options.kind)) {
    DCHECK(options.deoptimization_data.is_null());
    Tagged<TrustedObject> data =
        *options.bytecode_or_interpreter_data.ToHandleChecked();
    DCHECK(IsBytecodeArray(data) || IsInterpreterData(data));
    code->set_bytecode_or_interpreter_data(data);
  } else if (CodeKindUsesDeoptimizationData(options.kind)) {
    DCHECK(options.bytecode_or_interpreter_data.is_null());
    code->set_deoptimization_data(
        *options.deoptimization_data.ToHandleChecked());
  } else {
    DCHECK(options.deoptimization_data.is_null());
    DCHECK(options.bytecode_or_interpreter_data.is_null());
    code->clear_deoptimization_data_and_interpreter_data();
  }

  // Set bytecode offset table or source position table.
  if (CodeKindUsesBytecodeOffsetTable(options.kind)) {
    DCHECK(options.source_position_table.is_null());
    code->set_bytecode_offset_table(
        *options.bytecode_offset_table.ToHandleChecked());
  } else if (CodeKindMayLackSourcePositionTable(options.kind)) {
    DCHECK(options.bytecode_offset_table.is_null());
    Handle<TrustedByteArray> table;
    if (options.source_position_table.ToHandle(&table)) {
      code->set_source_position_table(*table);
    } else {
      code->clear_source_position_table_and_bytecode_offset_table();
    }
  } else {
    DCHECK(options.bytecode_offset_table.is_null());
    code->set_source_position_table(
        *options.source_position_table.ToHandleChecked());
  }

  // Set instruction stream and entrypoint.
  Handle<InstructionStream> istream;
  if (options.instruction_stream.ToHandle(&istream)) {
    DCHECK_EQ(options.instruction_start, kNullAddress);
    code->SetInstructionStreamAndInstructionStart(isolate(), *istream);
  } else {
    DCHECK_NE(options.instruction_start, kNullAddress);
    code->set_raw_instruction_stream(Smi::zero(), SKIP_WRITE_BARRIER);
    code->SetInstructionStartForOffHeapBuiltin(isolate(),
                                               options.instruction_start);
  }

  wrapper->set_code(code);
  code->set_wrapper(*wrapper);

  code->clear_padding();
  return handle(code, isolate());
}

template <typename Impl>
DirectHandle<CodeWrapper> FactoryBase<Impl>::NewCodeWrapper() {
  DirectHandle<CodeWrapper> wrapper(
      Cast<CodeWrapper>(NewWithImmortalMap(read_only_roots().code_wrapper_map(),
                                           AllocationType::kOld)),
      isolate());
  // The CodeWrapper is typically created before the Code object it wraps, so
  // the code field cannot yet be set. However, as a heap verifier might see
  // the wrapper before the field can be set, we need to clear the field here.
  wrapper->clear_code();
  return wrapper;
}

template <typename Impl>
Handle<FixedArray> FactoryBase<Impl>::NewFixedArray(uint32_t length,
                                                    AllocationType allocation,
                                                    AllocationHint hint) {
  return FixedArray::New(isolate(), length, allocation, hint);
}

template <typename Impl>
Handle<TrustedFixedArray> FactoryBase<Impl>::NewTrustedFixedArray(
    int length, AllocationType allocation) {
  DCHECK(allocation == AllocationType::kTrusted ||
         allocation == AllocationType::kSharedTrusted);

  // TODO(saelo): Move this check to TrustedFixedArray::New once we have a RO
  // trusted space.
  if (length == 0) return empty_trusted_fixed_array();
  return TrustedFixedArray::New(isolate(), length, allocation);
}

template <typename Impl>
Handle<ProtectedFixedArray> FactoryBase<Impl>::NewProtectedFixedArray(
    int length, bool shared) {
  if (length == 0) return empty_protected_fixed_array();
  return ProtectedFixedArray::New(isolate(), length, shared);
}

template <typename Impl>
Handle<FixedArray> FactoryBase<Impl>::NewFixedArrayWithMap(
    DirectHandle<Map> map, int length, AllocationType allocation) {
  // Zero-length case must be handled outside, where the knowledge about
  // the map is.
  DCHECK_LT(0, length);
  return NewFixedArrayWithFiller(map, length, undefined_value(), allocation);
}

template <typename Impl>
Handle<FixedArray> FactoryBase<Impl>::NewFixedArrayWithHoles(
    uint32_t length, AllocationType allocation) {
  if (length == 0) return impl()->empty_fixed_array();
  return NewFixedArrayWithFiller(fixed_array_map(), length, the_hole_value(),
                                 allocation);
}

template <typename Impl>
Handle<FixedArray> FactoryBase<Impl>::NewFixedArrayWithFiller(
    DirectHandle<Map> map, uint32_t length, DirectHandle<HeapObject> filler,
    AllocationType allocation) {
  Tagged<HeapObject> result = AllocateRawFixedArray(length, allocation);
  DisallowGarbageCollection no_gc;
  DCHECK(ReadOnlyHeap::Contains(*map));
  DCHECK(ReadOnlyHeap::Contains(*filler));
  result->set_map_after_allocation(isolate(), *map, SKIP_WRITE_BARRIER);
  Tagged<FixedArray> array = Cast<FixedArray>(result);
  array->set_length(length);
  MemsetTagged(array->RawFieldOfFirstElement(), *filler, length);
  return handle(array, isolate());
}

template <typename Impl>
DirectHandle<FixedArray> FactoryBase<Impl>::NewFixedArrayWithZeroes(
    uint32_t length, AllocationType allocation) {
  if (length == 0) return impl()->empty_fixed_array();
  if (length > FixedArray::kMaxLength) {
    base::FatalNoSecurityImpact("Invalid FixedArray size %d", length);
  }
  Tagged<HeapObject> result = AllocateRawFixedArray(length, allocation);
  DisallowGarbageCollection no_gc;
  result->set_map_after_allocation(
      isolate(), read_only_roots().fixed_array_map(), SKIP_WRITE_BARRIER);
  Tagged<FixedArray> array = Cast<FixedArray>(result);
  array->set_length(length);
  MemsetTagged(array->RawFieldOfFirstElement(), Smi::zero(), length);
  return direct_handle(array, isolate());
}

template <typename Impl>
Handle<FixedArrayBase> FactoryBase<Impl>::NewFixedDoubleArray(
    uint32_t length, AllocationType allocation) {
  return FixedDoubleArray::New(isolate(), length, allocation);
}

template <typename Impl>
Handle<WeakFixedArray> FactoryBase<Impl>::NewWeakFixedArrayWithMap(
    Tagged<Map> map, int length, AllocationType allocation) {
  // Zero-length case must be handled outside.
  DCHECK_LT(0, length);
  DCHECK(ReadOnlyHeap::Contains(map));

  Tagged<HeapObject> result =
      AllocateRawArray(WeakFixedArray::SizeFor(length), allocation);
  result->set_map_after_allocation(isolate(), map, SKIP_WRITE_BARRIER);
  DisallowGarbageCollection no_gc;
  Tagged<WeakFixedArray> array = Cast<WeakFixedArray>(result);
  array->set_length(length);
  MemsetTagged(ObjectSlot(array->RawFieldOfFirstElement()),
               read_only_roots().undefined_value(), length);

  return handle(array, isolate());
}

template <typename Impl>
Handle<WeakFixedArray> FactoryBase<Impl>::NewWeakFixedArray(
    int length, AllocationType allocation) {
  return WeakFixedArray::New(isolate(), length, allocation);
}

template <typename Impl>
Handle<TrustedWeakFixedArray> FactoryBase<Impl>::NewTrustedWeakFixedArray(
    int length) {
  // TODO(saelo): Move this check to TrustedWeakFixedArray::New once we have a
  // RO trusted space.
  if (length == 0) return empty_trusted_weak_fixed_array();
  return TrustedWeakFixedArray::New(isolate(), length);
}

template <typename Impl>
Handle<ProtectedWeakFixedArray> FactoryBase<Impl>::NewProtectedWeakFixedArray(
    int length) {
  // TODO(saelo): Move this check to ProtectedWeakFixedArray::New once we have
  // a RO trusted space.
  if (length == 0) return empty_protected_weak_fixed_array();
  return ProtectedWeakFixedArray::New(isolate(), length);
}

template <typename Impl>
Handle<ByteArray> FactoryBase<Impl>::NewByteArray(
    int length, AllocationType allocation, AllocationAlignment alignment) {
  return ByteArray::New(isolate(), length, allocation, alignment);
}

template <typename Impl>
Handle<TrustedByteArray> FactoryBase<Impl>::NewTrustedByteArray(
    int length, AllocationType allocation_type) {
  if (length == 0) return empty_trusted_byte_array();
  return TrustedByteArray::New(isolate(), length, allocation_type);
}

template <typename Impl>
DirectHandle<DeoptimizationLiteralArray>
FactoryBase<Impl>::NewDeoptimizationLiteralArray(int length) {
  return TrustedCast<DeoptimizationLiteralArray>(
      NewTrustedWeakFixedArray(length));
}

template <typename Impl>
DirectHandle<DeoptimizationFrameTranslation>
FactoryBase<Impl>::NewDeoptimizationFrameTranslation(int length) {
  return TrustedCast<DeoptimizationFrameTranslation>(
      NewTrustedByteArray(length));
}

template <typename Impl>
Handle<BytecodeArray> FactoryBase<Impl>::NewBytecodeArray(
    int length, const uint8_t* raw_bytecodes, int frame_size,
    uint16_t parameter_count, uint16_t max_arguments,
    DirectHandle<TrustedFixedArray> constant_pool,
    DirectHandle<TrustedByteArray> handler_table, AllocationType allocation) {
  DCHECK(allocation == AllocationType::kTrusted ||
         allocation == AllocationType::kSharedTrusted);
  if (length < 0 || length > BytecodeArray::kMaxLength) {
    base::FatalNoSecurityImpact("Fatal JavaScript invalid size error %d",
                                length);
    UNREACHABLE();
  }
  DirectHandle<BytecodeWrapper> wrapper = NewBytecodeWrapper();
  int size = BytecodeArray::SizeFor(length);
  Tagged<HeapObject> result = AllocateRawWithImmortalMap(
      size, allocation, read_only_roots().bytecode_array_map());
  DisallowGarbageCollection no_gc;
  Tagged<BytecodeArray> instance = TrustedCast<BytecodeArray>(result);
  // BytecodeArrays are initially unpublished and are only published to the
  // sandbox after bytecode verification.
  instance->InitDontPublish(isolate());
  instance->set_length(length);
  instance->set_frame_size(frame_size);
  instance->set_parameter_count(parameter_count);
  instance->set_max_arguments(max_arguments);
  instance->set_incoming_new_target_or_generator_register(
      interpreter::Register::invalid_value());
  instance->set_constant_pool(*constant_pool);
  instance->set_handler_table(*handler_table);
  instance->clear_source_position_table(kReleaseStore);
  instance->set_wrapper(*wrapper);
  CopyBytes(reinterpret_cast<uint8_t*>(instance->GetFirstBytecodeAddress()),
            raw_bytecodes, length);
  instance->clear_padding();
  return handle(instance, isolate());
}

template <typename Impl>
DirectHandle<BytecodeWrapper> FactoryBase<Impl>::NewBytecodeWrapper(
    AllocationType allocation) {
  DCHECK(allocation == AllocationType::kOld ||
         allocation == AllocationType::kSharedOld);

  DirectHandle<BytecodeWrapper> wrapper(
      Cast<BytecodeWrapper>(NewWithImmortalMap(
          read_only_roots().bytecode_wrapper_map(), allocation)),
      isolate());
  // The BytecodeWrapper is typically created before the BytecodeArray it
  // wraps, so the bytecode field cannot yet be set. However, as a heap
  // verifier might see the wrapper before the field can be set, we need to
  // clear the field here.
  wrapper->clear_bytecode();
  return wrapper;
}

template <typename Impl>
Handle<Script> FactoryBase<Impl>::NewScript(
    DirectHandle<UnionOf<String, Undefined>> source,
    ScriptEventType script_event_type) {
  return NewScriptWithId(source, isolate()->GetNextScriptId(),
                         script_event_type);
}

template <typename Impl>
Handle<Script> FactoryBase<Impl>::NewScriptWithId(
    DirectHandle<UnionOf<String, Undefined>> source, int script_id,
    ScriptEventType script_event_type) {
  DCHECK(IsString(*source) || IsUndefined(*source));
  // Create and initialize script object.
  ReadOnlyRoots roots = read_only_roots();
  Handle<Script> script = handle(
      NewStructInternal<Script>(SCRIPT_TYPE, AllocationType::kOld), isolate());
  {
    DisallowGarbageCollection no_gc;
    Tagged<Script> raw = *script;
    raw->set_source(*source);
    raw->set_name(roots.undefined_value(), SKIP_WRITE_BARRIER);
    raw->set_id(script_id);
    raw->set_line_offset(0);
    raw->set_column_offset(0);
    raw->set_context_data(roots.undefined_value(), SKIP_WRITE_BARRIER);
    raw->set_type(Script::Type::kNormal);
    raw->set_line_ends(Smi::zero());
    raw->set_eval_from_shared_or_wrapped_arguments(roots.undefined_value(),
                                                   SKIP_WRITE_BARRIER);
    raw->set_eval_from_position(0);
    raw->set_infos(roots.empty_weak_fixed_array(), SKIP_WRITE_BARRIER);
    raw->set_flags(0);
    raw->set_host_defined_options(roots.empty_fixed_array(),
                                  SKIP_WRITE_BARRIER);
    raw->set_source_hash(roots.undefined_value(), SKIP_WRITE_BARRIER);
    raw->set_compiled_lazy_function_positions(roots.undefined_value(),
                                              SKIP_WRITE_BARRIER);
#ifdef V8_SCRIPTORMODULE_LEGACY_LIFETIME
    raw->set_script_or_modules(roots.empty_array_list());
#endif
  }
  impl()->ProcessNewScript(script, script_event_type);
  return script;
}

template <typename Impl>
DirectHandle<SloppyArgumentsElements>
FactoryBase<Impl>::NewSloppyArgumentsElements(
    int length, DirectHandle<Context> context,
    DirectHandle<FixedArray> arguments, AllocationType allocation) {
  Tagged<SloppyArgumentsElements> result =
      Cast<SloppyArgumentsElements>(AllocateRawWithImmortalMap(
          SloppyArgumentsElements::SizeFor(length), allocation,
          read_only_roots().sloppy_arguments_elements_map()));

  DisallowGarbageCollection no_gc;
  WriteBarrierMode write_barrier_mode = allocation == AllocationType::kYoung
                                            ? SKIP_WRITE_BARRIER
                                            : UPDATE_WRITE_BARRIER;
  result->set_length(length);
  result->set_context(*context, write_barrier_mode);
  result->set_arguments(*arguments, write_barrier_mode);
  return direct_handle(result, isolate());
}

template <typename Impl>
DirectHandle<ArrayList> FactoryBase<Impl>::NewArrayList(
    int size, AllocationType allocation) {
  return ArrayList::New(isolate(), size, allocation);
}

template <typename Impl>
Handle<SharedFunctionInfo> FactoryBase<Impl>::NewSharedFunctionInfoForLiteral(
    FunctionLiteral* literal, DirectHandle<Script> script, bool is_toplevel) {
  FunctionKind kind = literal->kind();
  Handle<SharedFunctionInfo> shared =
      NewSharedFunctionInfo(literal->GetName(isolate()), {},
                            Builtin::kCompileLazy, 0, kDontAdapt, kind);
  shared->set_function_literal_id(literal->function_literal_id(),
                                  kRelaxedStore);
  literal->set_shared_function_info(shared);
  SharedFunctionInfo::InitFromFunctionLiteral(isolate(), literal, is_toplevel);
  shared->SetScript(isolate(), read_only_roots(), *script,
                    literal->function_literal_id(), false);
  return shared;
}

template <typename Impl>
Handle<SharedFunctionInfo> FactoryBase<Impl>::CloneSharedFunctionInfo(
    DirectHandle<SharedFunctionInfo> other) {
  Tagged<Map> map = read_only_roots().shared_function_info_map();

  Tagged<SharedFunctionInfo> shared =
      Cast<SharedFunctionInfo>(NewWithImmortalMap(map, AllocationType::kOld));
  DisallowGarbageCollection no_gc;

  shared->CopyFrom(*other, isolate());

  return handle(shared, isolate());
}

template <typename Impl>
DirectHandle<SharedFunctionInfoWrapper>
FactoryBase<Impl>::NewSharedFunctionInfoWrapper(
    DirectHandle<SharedFunctionInfo> sfi) {
  Tagged<Map> map = read_only_roots().shared_function_info_wrapper_map();
  Tagged<SharedFunctionInfoWrapper> wrapper =
      TrustedCast<SharedFunctionInfoWrapper>(
          NewWithImmortalMap(map, AllocationType::kTrusted));

  wrapper->set_shared_info(*sfi);

  return direct_handle(wrapper, isolate());
}

template <typename Impl>
Handle<PreparseData> FactoryBase<Impl>::NewPreparseData(int data_length,
                                                        int children_length) {
  int size = PreparseData::SizeFor(data_length, children_length);
  Tagged<PreparseData> result = Cast<PreparseData>(AllocateRawWithImmortalMap(
      size, AllocationType::kOld, read_only_roots().preparse_data_map()));
  DisallowGarbageCollection no_gc;
  result->set_data_length(data_length);
  result->set_children_length(children_length);
  MemsetTagged(ObjectSlot(result->children()), read_only_roots().null_value(),
               children_length);
  result->clear_padding();
  return handle(result, isolate());
}

template <typename Impl>
DirectHandle<UncompiledDataWithoutPreparseData>
FactoryBase<Impl>::NewUncompiledDataWithoutPreparseData(
    DirectHandle<String> inferred_name, int32_t start_position,
    int32_t end_position) {
  int size = sizeof(UncompiledDataWithoutPreparseData);
  Tagged<Map> map =
      read_only_roots().uncompiled_data_without_preparse_data_map();
  Tagged<UncompiledDataWithoutPreparseData> result =
      TrustedCast<UncompiledDataWithoutPreparseData>(
          AllocateRawWithImmortalMap(size, AllocationType::kTrusted, map));
  DisallowGarbageCollection no_gc;
  result->InitAndPublish(isolate());
  result->set_inferred_name(*inferred_name);
  result->set_start_position(start_position);
  result->set_end_position(end_position);
  return direct_handle(result, isolate());
}

template <typename Impl>
DirectHandle<UncompiledDataWithPreparseData>
FactoryBase<Impl>::NewUncompiledDataWithPreparseData(
    DirectHandle<String> inferred_name, int32_t start_position,
    int32_t end_position, DirectHandle<PreparseData> preparse_data) {
  int size = sizeof(UncompiledDataWithPreparseData);
  Tagged<Map> map = read_only_roots().uncompiled_data_with_preparse_data_map();
  Tagged<UncompiledDataWithPreparseData> result =
      TrustedCast<UncompiledDataWithPreparseData>(
          AllocateRawWithImmortalMap(size, AllocationType::kTrusted, map));
  DisallowGarbageCollection no_gc;
  result->InitAndPublish(isolate());
  result->set_inferred_name(*inferred_name);
  result->set_start_position(start_position);
  result->set_end_position(end_position);
  result->set_preparse_data(*preparse_data);
  return direct_handle(result, isolate());
}

template <typename Impl>
DirectHandle<UncompiledDataWithoutPreparseDataWithJob>
FactoryBase<Impl>::NewUncompiledDataWithoutPreparseDataWithJob(
    DirectHandle<String> inferred_name, int32_t start_position,
    int32_t end_position) {
  int size = sizeof(UncompiledDataWithoutPreparseDataWithJob);
  Tagged<Map> map =
      read_only_roots().uncompiled_data_without_preparse_data_with_job_map();
  Tagged<UncompiledDataWithoutPreparseDataWithJob> result =
      TrustedCast<UncompiledDataWithoutPreparseDataWithJob>(
          AllocateRawWithImmortalMap(size, AllocationType::kTrusted, map));
  DisallowGarbageCollection no_gc;
  result->InitAndPublish(isolate());
  result->set_inferred_name(*inferred_name);
  result->set_start_position(start_position);
  result->set_end_position(end_position);
  result->set_job(kNullAddress);
  return direct_handle(result, isolate());
}

template <typename Impl>
DirectHandle<UncompiledDataWithPreparseDataAndJob>
FactoryBase<Impl>::NewUncompiledDataWithPreparseDataAndJob(
    DirectHandle<String> inferred_name, int32_t start_position,
    int32_t end_position, DirectHandle<PreparseData> preparse_data) {
  int size = sizeof(UncompiledDataWithPreparseDataAndJob);
  Tagged<Map> map =
      read_only_roots().uncompiled_data_with_preparse_data_and_job_map();
  Tagged<UncompiledDataWithPreparseDataAndJob> result =
      TrustedCast<UncompiledDataWithPreparseDataAndJob>(
          AllocateRawWithImmortalMap(size, AllocationType::kTrusted, map));
  DisallowGarbageCollection no_gc;
  result->InitAndPublish(isolate());
  result->set_inferred_name(*inferred_name);
  result->set_start_position(start_position);
  result->set_end_position(end_position);
  result->set_preparse_data(*preparse_data);
  result->set_job(kNullAddress);
  return direct_handle(result, isolate());
}

template <typename Impl>
Handle<SharedFunctionInfo> FactoryBase<Impl>::NewSharedFunctionInfo(
    MaybeDirectHandle<String> maybe_name,
    MaybeDirectHandle<HeapObject> maybe_function_data, Builtin builtin, int len,
    AdaptArguments adapt, FunctionKind kind) {
  Handle<SharedFunctionInfo> shared =
      NewSharedFunctionInfo(AllocationType::kOld);
  DisallowGarbageCollection no_gc;
  Tagged<SharedFunctionInfo> raw = *shared;
  // Function names are assumed to be flat elsewhere.
  DirectHandle<String> shared_name;
  bool has_shared_name = maybe_name.ToHandle(&shared_name);
  if (has_shared_name) {
    DCHECK(shared_name->IsFlat());
    raw->set_name_or_scope_info(*shared_name, kReleaseStore);
  } else {
    DCHECK_EQ(raw->name_or_scope_info(kAcquireLoad),
              SharedFunctionInfo::kNoSharedNameSentinel);
  }

  DirectHandle<HeapObject> function_data;
  if (maybe_function_data.ToHandle(&function_data)) {
    // If we pass function_data then we shouldn't pass a builtin index, and
    // the function_data should not be code with a builtin.
    DCHECK(!Builtins::IsBuiltinId(builtin));
    DCHECK(!IsInstructionStream(*function_data));
    DCHECK(!IsCode(*function_data));
    if (IsExposedTrustedObject(*function_data)) {
      raw->SetTrustedData(TrustedCast<ExposedTrustedObject>(*function_data));
    } else {
      raw->SetUntrustedData(*function_data);
    }
  } else if (Builtins::IsBuiltinId(builtin)) {
    raw->set_builtin_id(builtin);
  } else {
    DCHECK(raw->HasBuiltinId());
    DCHECK_EQ(Builtin::kIllegal, raw->builtin_id());
  }

  raw->CalculateConstructAsBuiltin();
  raw->set_kind(kind);

  switch (adapt) {
    case AdaptArguments::kYes:
      raw->set_formal_parameter_count(JSParameterCount(len));
      break;
    case AdaptArguments::kNo:
      raw->DontAdaptArguments();
      break;
  }
  raw->set_length(len);

  DCHECK_IMPLIES(raw->HasBuiltinId(),
                 Builtins::CheckFormalParameterCount(
                     raw->builtin_id(), raw->length(),
                     raw->internal_formal_parameter_count_with_receiver()));
#ifdef VERIFY_HEAP
  if (v8_flags.verify_heap) raw->SharedFunctionInfoVerify(isolate());
#endif  // VERIFY_HEAP
  return shared;
}

template <typename Impl>
Handle<ObjectBoilerplateDescription>
FactoryBase<Impl>::NewObjectBoilerplateDescription(int boilerplate,
                                                   int all_properties,
                                                   int index_keys,
                                                   bool has_seen_proto) {
  return ObjectBoilerplateDescription::New(
      isolate(), boilerplate, all_properties, index_keys, has_seen_proto,
      AllocationType::kOld);
}

template <typename Impl>
Handle<ArrayBoilerplateDescription>
FactoryBase<Impl>::NewArrayBoilerplateDescription(
    ElementsKind elements_kind, DirectHandle<FixedArrayBase> constant_values) {
  auto result = NewStructInternal<ArrayBoilerplateDescription>(
      ARRAY_BOILERPLATE_DESCRIPTION_TYPE, AllocationType::kOld);
  DisallowGarbageCollection no_gc;
  result->set_elements_kind(elements_kind);
  result->set_constant_elements(*constant_values);
  return handle(result, isolate());
}

template <typename Impl>
DirectHandle<RegExpDataWrapper> FactoryBase<Impl>::NewRegExpDataWrapper() {
  DirectHandle<RegExpDataWrapper> wrapper(
      Cast<RegExpDataWrapper>(NewWithImmortalMap(
          read_only_roots().regexp_data_wrapper_map(), AllocationType::kOld)),
      isolate());
  wrapper->clear_data();
  return wrapper;
}

template <typename Impl>
DirectHandle<RegExpBoilerplateDescription>
FactoryBase<Impl>::NewRegExpBoilerplateDescription(
    DirectHandle<RegExpData> data, DirectHandle<String> source,
    Tagged<Smi> flags) {
  auto result = NewStructInternal<RegExpBoilerplateDescription>(
      REG_EXP_BOILERPLATE_DESCRIPTION_TYPE, AllocationType::kOld);
  DisallowGarbageCollection no_gc;
  result->set_data(*data);
  result->set_source(*source);
  result->set_flags(flags.value());
  return direct_handle(result, isolate());
}

template <typename Impl>
Handle<TemplateObjectDescription>
FactoryBase<Impl>::NewTemplateObjectDescription(
    DirectHandle<FixedArray> raw_strings,
    DirectHandle<FixedArray> cooked_strings) {
  DCHECK_EQ(raw_strings->length(), cooked_strings->length());
  DCHECK_LT(0, raw_strings->length());
  auto result = NewStructInternal<TemplateObjectDescription>(
      TEMPLATE_OBJECT_DESCRIPTION_TYPE, AllocationType::kOld);
  DisallowGarbageCollection no_gc;
  result->set_raw_strings(*raw_strings);
  result->set_cooked_strings(*cooked_strings);
  return handle(result, isolate());
}

template <typename Impl>
Handle<FeedbackMetadata> FactoryBase<Impl>::NewFeedbackMetadata(
    int slot_count, int create_closure_slot_count, AllocationType allocation) {
  DCHECK_LE(0, slot_count);
  int size = FeedbackMetadata::SizeFor(slot_count, create_closure_slot_count);
  Tagged<FeedbackMetadata> result =
      Cast<FeedbackMetadata>(AllocateRawWithImmortalMap(
          size, allocation, read_only_roots().feedback_metadata_map()));
  result->set_slot_count(slot_count);
  result->set_create_closure_slot_count(create_closure_slot_count);

  // Initialize the data section to 0.
  int data_size = size - FeedbackMetadata::kHeaderSize;
  Address data_start = result->address() + FeedbackMetadata::kHeaderSize;
  memset(reinterpret_cast<uint8_t*>(data_start), 0, data_size);
  // Fields have been zeroed out but not initialized, so this object will not
  // pass object verification at this point.
  return handle(result, isolate());
}

template <typename Impl>
Handle<CoverageInfo> FactoryBase<Impl>::NewCoverageInfo(
    const ZoneVector<SourceRange>& slots) {
  const int slot_count = static_cast<int>(slots.size());

  int size = CoverageInfo::SizeFor(slot_count);
  Tagged<Map> map = read_only_roots().coverage_info_map();
  Tagged<CoverageInfo> info = Cast<CoverageInfo>(
      AllocateRawWithImmortalMap(size, AllocationType::kOld, map));
  info->set_slot_count(slot_count);
  for (int i = 0; i < slot_count; i++) {
    SourceRange range = slots[i];
    info->InitializeSlot(i, range.start, range.end);
  }
  return handle(info, isolate());
}

template <typename Impl>
Handle<String> FactoryBase<Impl>::MakeOrFindTwoCharacterString(uint16_t c1,
                                                               uint16_t c2) {
  if ((c1 | c2) <= unibrow::Latin1::kMaxChar) {
    uint8_t buffer[] = {static_cast<uint8_t>(c1), static_cast<uint8_t>(c2)};
    return InternalizeString(base::Vector<const uint8_t>(buffer, 2));
  }
  uint16_t buffer[] = {c1, c2};
  return InternalizeString(base::Vector<const uint16_t>(buffer, 2));
}

template <typename Impl>
template <class StringTableKey>
Handle<String> FactoryBase<Impl>::InternalizeStringWithKey(
    StringTableKey* key) {
  return indirect_handle(isolate()->string_table()->LookupKey(isolate(), key),
                         isolate());
}

template EXPORT_TEMPLATE_DEFINE(V8_EXPORT_PRIVATE)
    Handle<String> FactoryBase<Factory>::InternalizeStringWithKey(
        OneByteStringKey* key);
template EXPORT_TEMPLATE_DEFINE(V8_EXPORT_PRIVATE)
    Handle<String> FactoryBase<Factory>::InternalizeStringWithKey(
        TwoByteStringKey* key);
template EXPORT_TEMPLATE_DEFINE(V8_EXPORT_PRIVATE)
    Handle<String> FactoryBase<Factory>::InternalizeStringWithKey(
        SeqOneByteSubStringKey* key);
template EXPORT_TEMPLATE_DEFINE(V8_EXPORT_PRIVATE)
    Handle<String> FactoryBase<Factory>::InternalizeStringWithKey(
        SeqTwoByteSubStringKey* key);

template EXPORT_TEMPLATE_DEFINE(V8_EXPORT_PRIVATE)
    Handle<String> FactoryBase<LocalFactory>::InternalizeStringWithKey(
        OneByteStringKey* key);
template EXPORT_TEMPLATE_DEFINE(V8_EXPORT_PRIVATE)
    Handle<String> FactoryBase<LocalFactory>::InternalizeStringWithKey(
        TwoByteStringKey* key);

template <typename Impl>
Handle<String> FactoryBase<Impl>::InternalizeString(
    base::Vector<const uint8_t> string, bool convert_encoding) {
  SequentialStringKey<uint8_t> key(string, HashSeed(read_only_roots()),
                                   convert_encoding);
  return InternalizeStringWithKey(&key);
}

template <typename Impl>
Handle<String> FactoryBase<Impl>::InternalizeString(
    base::Vector<const uint16_t> string, bool convert_encoding) {
  SequentialStringKey<uint16_t> key(string, HashSeed(read_only_roots()),
                                    convert_encoding);
  return InternalizeStringWithKey(&key);
}

template <typename Impl>
Handle<SeqOneByteString> FactoryBase<Impl>::NewOneByteInternalizedString(
    base::Vector<const uint8_t> str, uint32_t raw_hash_field) {
  Handle<SeqOneByteString> result =
      AllocateRawOneByteInternalizedString(str.length(), raw_hash_field);
  // No synchronization is needed since the shared string hasn't yet escaped to
  // script.
  DisallowGarbageCollection no_gc;
  MemCopy(result->GetChars(no_gc, SharedStringAccessGuardIfNeeded::NotNeeded()),
          str.begin(), str.length());
  return result;
}

template <typename Impl>
Handle<SeqTwoByteString> FactoryBase<Impl>::NewTwoByteInternalizedString(
    base::Vector<const base::uc16> str, uint32_t raw_hash_field) {
  Handle<SeqTwoByteString> result =
      AllocateRawTwoByteInternalizedString(str.length(), raw_hash_field);
  // No synchronization is needed since the shared string hasn't yet escaped to
  // script.
  DisallowGarbageCollection no_gc;
  MemCopy(result->GetChars(no_gc, SharedStringAccessGuardIfNeeded::NotNeeded()),
          str.begin(), str.length() * base::kUC16Size);
  return result;
}

template <typename Impl>
DirectHandle<SeqOneByteString>
FactoryBase<Impl>::NewOneByteInternalizedStringFromTwoByte(
    base::Vector<const base::uc16> str, uint32_t raw_hash_field) {
  DirectHandle<SeqOneByteString> result =
      AllocateRawOneByteInternalizedString(str.length(), raw_hash_field);
  DisallowGarbageCollection no_gc;
  CopyChars(
      result->GetChars(no_gc, SharedStringAccessGuardIfNeeded::NotNeeded()),
      str.begin(), str.length());
  return result;
}

template <typename Impl>
template <typename SeqStringT>
MaybeHandle<SeqStringT> FactoryBase<Impl>::NewRawStringWithMap(
    int length, Tagged<Map> map, AllocationType allocation,
    AllocationHint hint) {
  DCHECK(SeqStringT::IsCompatibleMap(map, read_only_roots()));
  DCHECK_IMPLIES(!StringShape(map).IsShared(),
                 RefineAllocationTypeForInPlaceInternalizableString(
                     allocation, map) == allocation);
  if (length < 0 || static_cast<uint32_t>(length) > String::kMaxLength) {
    THROW_NEW_ERROR(isolate(), NewInvalidStringLengthError());
  }
  DCHECK_GT(length, 0);  // Use Factory::empty_string() instead.
  int size = SeqStringT::SizeFor(length);
  DCHECK_GE(ObjectTraits<SeqStringT>::kMaxSize, size);

  Tagged<SeqStringT> string = Cast<SeqStringT>(AllocateRawWithImmortalMap(
      size, allocation, map, AllocationAlignment::kTaggedAligned, hint));
  DisallowGarbageCollection no_gc;
  string->clear_padding_destructively(length);
  string->set_length(length);
  string->set_raw_hash_field(String::kEmptyHashField);
  DCHECK_EQ(size, string->Size());
  return handle(string, isolate());
}

template <typename Impl>
MaybeHandle<SeqOneByteString> FactoryBase<Impl>::NewRawOneByteString(
    uint32_t length, AllocationType allocation, AllocationHint hint) {
  Tagged<Map> map = read_only_roots().seq_one_byte_string_map();
  return NewRawStringWithMap<SeqOneByteString>(
      length, map,
      RefineAllocationTypeForInPlaceInternalizableString(allocation, map),
      hint);
}

template <typename Impl>
MaybeHandle<SeqTwoByteString> FactoryBase<Impl>::NewRawTwoByteString(
    uint32_t length, AllocationType allocation, AllocationHint hint) {
  Tagged<Map> map = read_only_roots().seq_two_byte_string_map();
  return NewRawStringWithMap<SeqTwoByteString>(
      length, map,
      RefineAllocationTypeForInPlaceInternalizableString(allocation, map),
      hint);
}

template <typename Impl>
MaybeHandle<SeqOneByteString> FactoryBase<Impl>::NewRawSharedOneByteString(
    int length) {
  return NewRawStringWithMap<SeqOneByteString>(
      length, read_only_roots().shared_seq_one_byte_string_map(),
      AllocationType::kSharedOld, AllocationHint());
}

template <typename Impl>
MaybeHandle<SeqTwoByteString> FactoryBase<Impl>::NewRawSharedTwoByteString(
    int length) {
  return NewRawStringWithMap<SeqTwoByteString>(
      length, read_only_roots().shared_seq_two_byte_string_map(),
      AllocationType::kSharedOld, AllocationHint());
}

template <typename Impl>
template <template <typename> typename HandleType>
  requires(std::is_convertible_v<HandleType<String>, DirectHandle<String>>)
HandleType<String>::MaybeType FactoryBase<Impl>::NewConsString(
    HandleType<String> left, HandleType<String> right,
    AllocationType allocation) {
  if (IsThinString(*left)) {
    left = HandleType<String>(Cast<ThinString>(*left)->actual(), isolate());
  }
  if (IsThinString(*right)) {
    right = HandleType<String>(Cast<ThinString>(*right)->actual(), isolate());
  }
  uint32_t left_length = left->length();
  if (left_length == 0) return right;
  uint32_t right_length = right->length();
  if (right_length == 0) return left;

  uint32_t length = left_length + right_length;

  if (length == 2) {
    uint16_t c1 = left->Get(0, isolate());
    uint16_t c2 = right->Get(0, isolate());
    return MakeOrFindTwoCharacterString(c1, c2);
  }

  // Make sure that an out of memory exception is thrown if the length
  // of the new cons string is too large.
  if (length > String::kMaxLength || length < 0) {
    THROW_NEW_ERROR(isolate(), NewInvalidStringLengthError());
  }

  bool left_is_one_byte = left->IsOneByteRepresentation();
  bool right_is_one_byte = right->IsOneByteRepresentation();
  bool is_one_byte = left_is_one_byte && right_is_one_byte;

  // If the resulting string is small make a flat string.
  if (length < ConsString::kMinLength) {
    // Note that neither of the two inputs can be a slice because:
    static_assert(ConsString::kMinLength <= SlicedString::kMinLength);
    DCHECK(left->IsFlat());
    DCHECK(right->IsFlat());

    static_assert(ConsString::kMinLength <= String::kMaxLength);
    if (is_one_byte) {
      HandleType<SeqOneByteString> result =
          NewRawOneByteString(length, allocation).ToHandleChecked();
      DisallowGarbageCollection no_gc;
      SharedStringAccessGuardIfNeeded access_guard(isolate());
      uint8_t* dest = result->GetChars(no_gc, access_guard);
      // Copy left part.
      {
        const uint8_t* src =
            left->template GetDirectStringChars<uint8_t>(no_gc, access_guard);
        CopyChars(dest, src, left_length);
      }
      // Copy right part.
      {
        const uint8_t* src =
            right->template GetDirectStringChars<uint8_t>(no_gc, access_guard);
        CopyChars(dest + left_length, src, right_length);
      }
      return result;
    }

    HandleType<SeqTwoByteString> result =
        NewRawTwoByteString(length, allocation).ToHandleChecked();

    DisallowGarbageCollection no_gc;
    SharedStringAccessGuardIfNeeded access_guard(isolate());
    base::uc16* sink = result->GetChars(no_gc, access_guard);
    String::WriteToFlat(*left, sink, 0, left->length(), access_guard);
    String::WriteToFlat(*right, sink + left->length(), 0, right->length(),
                        access_guard);
    return result;
  }

  return NewConsString(left, right, length, is_one_byte, allocation);
}

template <typename Impl>
Handle<String> FactoryBase<Impl>::NewConsString(DirectHandle<String> left,
                                                DirectHandle<String> right,
                                                int length, bool one_byte,
                                                AllocationType allocation) {
  DCHECK(!IsThinString(*left));
  DCHECK(!IsThinString(*right));
  DCHECK_GE(length, ConsString::kMinLength);
  DCHECK_LE(length, String::kMaxLength);

  Tagged<ConsString> result = Cast<ConsString>(
      one_byte ? NewWithImmortalMap(
                     read_only_roots().cons_one_byte_string_map(), allocation)
               : NewWithImmortalMap(
                     read_only_roots().cons_two_byte_string_map(), allocation));

  DisallowGarbageCollection no_gc;
  WriteBarrierModeScope mode = result->GetWriteBarrierMode(no_gc);
  result->set_raw_hash_field(String::kEmptyHashField);
  result->set_length(length);
  result->set_first(*left, *mode);
  result->set_second(*right, *mode);
  return handle(result, isolate());
}

template <typename Impl>
Handle<String> FactoryBase<Impl>::LookupSingleCharacterStringFromCode(
    uint16_t code) {
  if (code <= String::kMaxOneByteCharCode) {
    return Cast<String>(
        isolate()->root_handle(RootsTable::SingleCharacterStringIndex(code)));
  }
  uint16_t buffer[] = {code};
  return InternalizeString(base::Vector<const uint16_t>(buffer, 1));
}

template <typename Impl>
MaybeHandle<String> FactoryBase<Impl>::NewStringFromOneByte(
    base::Vector<const uint8_t> string, AllocationType allocation) {
  DCHECK_NE(allocation, AllocationType::kReadOnly);
  int length = string.length();
  if (length == 0) return empty_string();
  if (length == 1) return LookupSingleCharacterStringFromCode(string[0]);
  Handle<SeqOneByteString> result;
  ASSIGN_RETURN_ON_EXCEPTION(isolate(), result,
                             NewRawOneByteString(string.length(), allocation));

  DisallowGarbageCollection no_gc;
  // Copy the characters into the new object.
  // SharedStringAccessGuardIfNeeded is NotNeeded because {result} is freshly
  // allocated and hasn't escaped the factory yet, so it can't be concurrently
  // accessed.
  CopyChars(Cast<SeqOneByteString>(*result)->GetChars(
                no_gc, SharedStringAccessGuardIfNeeded::NotNeeded()),
            string.begin(), length);
  return result;
}
namespace {

template <typename Impl>
V8_INLINE Handle<String> StringViewToString(FactoryBase<Impl>* factory,
                                            std::string_view string,
                                            NumberCacheMode mode) {
  // We tenure the allocated string since it is referenced from the
  // number-string cache which lives in the old space.
  AllocationType type = mode == NumberCacheMode::kIgnore
                            ? AllocationType::kYoung
                            : AllocationType::kOld;
  return factory->NewStringFromAsciiChecked(string, type);
}

}  // namespace

template <typename Impl>
Handle<String> FactoryBase<Impl>::NumberToString(DirectHandle<Object> number,
                                                 NumberCacheMode mode) {
  SLOW_DCHECK(IsNumber(*number));
  if (IsSmi(*number)) return SmiToString(Cast<Smi>(*number), mode);

  double double_value = Cast<HeapNumber>(number)->value();
  // Try to canonicalize doubles.
  return DoubleToString(double_value, true, mode);
}

template <typename Impl>
Handle<String> FactoryBase<Impl>::DoubleToString(double value,
                                                 bool canonicalize,
                                                 NumberCacheMode mode) {
  if (canonicalize) {
    // Try to canonicalize doubles.
    int smi_value;
    if (DoubleToSmiInteger(value, &smi_value)) {
      return SmiToString(Smi::FromInt(smi_value), mode);
    }
  }

  // LocalFactory does not have access to number string cache, only
  // main thread Factory does (since it's a mutable root).
  constexpr bool kCanUseCache = std::is_same_v<Impl, Factory>;

  InternalIndex entry = InternalIndex::NotFound();
  uint64_t value_bits = 0;
  if constexpr (kCanUseCache) {
    if (mode != NumberCacheMode::kIgnore) {
      value_bits = base::bit_cast<uint64_t>(value);
      entry = DoubleStringCache::GetEntryFor(isolate(), value_bits);
    }
    if (mode == NumberCacheMode::kBoth) {
      Handle<Object> cached =
          DoubleStringCache::Get(isolate(), entry, value_bits);
      if (!IsUndefined(*cached, isolate())) return Cast<String>(cached);
    }
  }

  Handle<String> result;
  if (value == 0) {
    result = zero_string();
  } else if (std::isnan(value)) {
    result = NaN_string();
  } else {
    char arr[kNumberToStringBufferSize];
    base::Vector<char> buffer(arr, arraysize(arr));
    std::string_view string = DoubleToStringView(value, buffer);
    result = StringViewToString(this, string, mode);
  }
  if constexpr (kCanUseCache) {
    if (mode != NumberCacheMode::kIgnore) {
      DoubleStringCache::Set(isolate(), entry, value_bits, result);
    }
  }
  return result;
}

template <typename Impl>
inline Handle<String> FactoryBase<Impl>::SmiToString(Tagged<Smi> number,
                                                     NumberCacheMode mode) {
  // LINT.IfChange(CheckPreallocatedNumberStrings)
  {
    DCHECK_EQ(kPreallocatedNumberStringTableSize,
              preallocated_number_string_table()->length());
    int index = number.value();
    if (static_cast<unsigned>(index) < kPreallocatedNumberStringTableSize) {
      return handle(
          Cast<String>(preallocated_number_string_table()->get(index)),
          isolate());
    }
  }
  // LINT.ThenChange(/src/codegen/code-stub-assembler.cc:CheckPreallocatedNumberStrings)

  // LocalFactory does not have access to the number_string_cache, only
  // main thread Factory does (since it's a mutable root).
  constexpr bool kCanUseCache = std::is_same_v<Impl, Factory>;

  InternalIndex entry = InternalIndex::NotFound();
  if constexpr (kCanUseCache) {
    if (mode != NumberCacheMode::kIgnore) {
      entry = SmiStringCache::GetEntryFor(isolate(), number);
    }
    if (mode == NumberCacheMode::kBoth) {
      Handle<Object> cached = SmiStringCache::Get(isolate(), entry, number);
      if (!IsUndefined(*cached, isolate())) return Cast<String>(cached);
    }
  }

  Handle<String> result;
  {
    char arr[kNumberToStringBufferSize];
    base::Vector<char> buffer(arr, arraysize(arr));
    std::string_view string = IntToStringView(number.value(), buffer);
    result = StringViewToString(this, string, mode);
  }
  if constexpr (kCanUseCache) {
    if (mode != NumberCacheMode::kIgnore) {
      SmiStringCache::Set(isolate(), entry, number, result);
    }
  }

  // Compute the hash here (rather than letting the caller take care of it) so
  // that the "cache hit" case above doesn't have to bother with it.
  static_assert(Smi::kMaxValue <= std::numeric_limits<uint32_t>::max());
  {
    DisallowGarbageCollection no_gc;
    Tagged<String> raw = *result;
    if (raw->raw_hash_field() == String::kEmptyHashField &&
        number.value() >= 0) {
      uint32_t raw_hash_field = StringHasher::MakeArrayIndexHash(
          static_cast<uint32_t>(number.value()), raw->length(),
          HashSeed(read_only_roots()));
      raw->set_raw_hash_field(raw_hash_field);
    }
  }
  return result;
}

template <typename Impl>
Handle<FreshlyAllocatedBigInt> FactoryBase<Impl>::NewBigInt(
    uint32_t length, AllocationType allocation) {
  if (length > BigInt::kMaxLength) {
    base::FatalNoSecurityImpact("Fatal JavaScript invalid size error %d",
                                length);
    UNREACHABLE();
  }
  Tagged<HeapObject> result = AllocateRawWithImmortalMap(
      BigInt::SizeFor(length), allocation, read_only_roots().bigint_map());
  DisallowGarbageCollection no_gc;
  Tagged<FreshlyAllocatedBigInt> bigint = Cast<FreshlyAllocatedBigInt>(result);
  bigint->clear_padding();
  return handle(bigint, isolate());
}

template <typename Impl>
Handle<ScopeInfo> FactoryBase<Impl>::NewScopeInfo(int length,
                                                  AllocationType type) {
  DCHECK(type == AllocationType::kOld || type == AllocationType::kReadOnly);
  int size = ScopeInfo::SizeFor(length);
  Tagged<HeapObject> obj = AllocateRawWithImmortalMap(
      size, type, read_only_roots().scope_info_map());
  Tagged<ScopeInfo> scope_info = Cast<ScopeInfo>(obj);
  MemsetTagged(scope_info->data_start(), read_only_roots().undefined_value(),
               length);
#if TAGGED_SIZE_8_BYTES
  scope_info->set_optional_padding(0);
#endif
  return handle(scope_info, isolate());
}

template <typename Impl>
DirectHandle<SourceTextModuleInfo>
FactoryBase<Impl>::NewSourceTextModuleInfo() {
  return Cast<SourceTextModuleInfo>(NewFixedArrayWithMap(
      module_info_map(), SourceTextModuleInfo::kLength, AllocationType::kOld));
}

template <typename Impl>
Handle<SharedFunctionInfo> FactoryBase<Impl>::NewSharedFunctionInfo(
    AllocationType allocation) {
  Tagged<Map> map = read_only_roots().shared_function_info_map();
  Tagged<SharedFunctionInfo> shared =
      Cast<SharedFunctionInfo>(NewWithImmortalMap(map, allocation));

  DisallowGarbageCollection no_gc;
  shared->Init(read_only_roots(), isolate()->GetAndIncNextUniqueSfiId());
  return handle(shared, isolate());
}

template <typename Impl>
Handle<DescriptorArray> FactoryBase<Impl>::NewDescriptorArray(
    int number_of_descriptors, int slack, AllocationType allocation) {
  int number_of_all_descriptors = number_of_descriptors + slack;
  // Zero-length case must be handled outside.
  DCHECK_LT(0, number_of_all_descriptors);
  int size = DescriptorArray::SizeFor(number_of_all_descriptors);
  Tagged<HeapObject> obj = AllocateRawWithImmortalMap(
      size, allocation, read_only_roots().descriptor_array_map());
  Tagged<DescriptorArray> array = Cast<DescriptorArray>(obj);

  auto raw_gc_state = DescriptorArrayMarkingState::kInitialGCState;
  if (allocation != AllocationType::kYoung &&
      allocation != AllocationType::kReadOnly) {
    auto* local_heap = allocation == AllocationType::kSharedOld
                           ? isolate()->shared_space_isolate()->heap()
                           : isolate()->heap();
    Heap* heap = local_heap->AsHeap();
    if (heap->incremental_marking()->IsMajorMarking()) {
      // Black allocation: We must create a full marked state.
      raw_gc_state = DescriptorArrayMarkingState::GetFullyMarkedState(
          heap->mark_compact_collector()->epoch(), number_of_descriptors);
    }
  }
  array->Initialize(read_only_roots().empty_enum_cache(),
                    read_only_roots().undefined_value(), number_of_descriptors,
                    slack, raw_gc_state);
  return handle(array, isolate());
}

template <typename Impl>
Handle<ClassPositions> FactoryBase<Impl>::NewClassPositions(int start,
                                                            int end) {
  auto result = NewStructInternal<ClassPositions>(CLASS_POSITIONS_TYPE,
                                                  AllocationType::kOld);
  result->set_start(start);
  result->set_end(end);
  return handle(result, isolate());
}

template <typename Impl>
Handle<SeqOneByteString>
FactoryBase<Impl>::AllocateRawOneByteInternalizedString(
    int length, uint32_t raw_hash_field) {
  CHECK_GE(String::kMaxLength, length);
  // The canonical empty_string is the only zero-length string we allow.
  DCHECK_IMPLIES(length == 0, !impl()->EmptyStringRootIsInitialized());

  Tagged<Map> map = read_only_roots().internalized_one_byte_string_map();
  const int size = SeqOneByteString::SizeFor(length);
  // TODO(jgruber): Can we promote these in ReadOnlyPromotion instead? There
  // must've been a reason we didn't do so initially, but it may no longer
  // apply.
  bool can_alloc_in_ro_space =
      impl()->CanAllocateInReadOnlySpace() && size <= kMaxRegularHeapObjectSize;
  const AllocationType allocation =
      RefineAllocationTypeForInPlaceInternalizableString(
          can_alloc_in_ro_space ? AllocationType::kReadOnly
                                : AllocationType::kOld,
          map);
  Tagged<HeapObject> result = AllocateRawWithImmortalMap(size, allocation, map);
  Tagged<SeqOneByteString> answer = Cast<SeqOneByteString>(result);
  DisallowGarbageCollection no_gc;
  answer->clear_padding_destructively(length);
  answer->set_length(length);
  answer->set_raw_hash_field(raw_hash_field);
  DCHECK_EQ(size, answer->Size());
  return handle(answer, isolate());
}

template <typename Impl>
Handle<SeqTwoByteString>
FactoryBase<Impl>::AllocateRawTwoByteInternalizedString(
    int length, uint32_t raw_hash_field) {
  CHECK_GE(String::kMaxLength, length);
  DCHECK_NE(0, length);  // Use Heap::empty_string() instead.

  Tagged<Map> map = read_only_roots().internalized_two_byte_string_map();
  int size = SeqTwoByteString::SizeFor(length);
  // TODO(jgruber): Can we promote these in ReadOnlyPromotion instead? There
  // must've been a reason we didn't do so initially, but it may no longer
  // apply.
  bool can_alloc_in_ro_space =
      impl()->CanAllocateInReadOnlySpace() && size <= kMaxRegularHeapObjectSize;
  Tagged<SeqTwoByteString> answer =
      Cast<SeqTwoByteString>(AllocateRawWithImmortalMap(
          size,
          RefineAllocationTypeForInPlaceInternalizableString(
              can_alloc_in_ro_space ? AllocationType::kReadOnly
                                    : AllocationType::kOld,
              map),
          map));
  DisallowGarbageCollection no_gc;
  answer->clear_padding_destructively(length);
  answer->set_length(length);
  answer->set_raw_hash_field(raw_hash_field);
  DCHECK_EQ(size, answer->Size());
  return handle(answer, isolate());
}

template <typename Impl>
Tagged<HeapObject> FactoryBase<Impl>::AllocateRawArray(
    int size, AllocationType allocation, AllocationHint hint,
    AllocationAlignment alignment) {
  Tagged<HeapObject> result = AllocateRaw(size, allocation, alignment, hint);
  if ((size >
       isolate()->heap()->AsHeap()->MaxRegularHeapObjectSize(allocation)) &&
      v8_flags.use_marking_progress_bar) {
    LargePage::FromHeapObject(isolate()->GetMainThreadIsolateUnsafe(), result)
        ->marking_progress_tracker()
        .Enable(size);
  }
  return result;
}

template <typename Impl>
Tagged<HeapObject> FactoryBase<Impl>::AllocateRawFixedArray(
    int length, AllocationType allocation) {
  if (length < 0 || length > FixedArray::kMaxLength) {
    base::FatalNoSecurityImpact("Fatal JavaScript invalid size error %d",
                                length);
    UNREACHABLE();
  }
  return AllocateRawArray(FixedArray::SizeFor(length), allocation);
}

template <typename Impl>
Tagged<HeapObject> FactoryBase<Impl>::AllocateRawWeakArrayList(
    int capacity, AllocationType allocation) {
  if (capacity < 0 || capacity > WeakArrayList::kMaxCapacity) {
    base::FatalNoSecurityImpact("Fatal JavaScript invalid size error %d",
                                capacity);
    UNREACHABLE();
  }
  return AllocateRawArray(WeakArrayList::SizeForCapacity(capacity), allocation);
}

template <typename Impl>
Tagged<HeapObject> FactoryBase<Impl>::NewWithImmortalMap(
    Tagged<Map> map, AllocationType allocation) {
  return AllocateRawWithImmortalMap(map->instance_size(), allocation, map);
}

template <typename Impl>
Tagged<HeapObject> FactoryBase<Impl>::AllocateRawWithImmortalMap(
    int size, AllocationType allocation, Tagged<Map> map,
    AllocationAlignment alignment, AllocationHint hint) {
  // TODO(delphick): Potentially you could also pass an immortal immovable Map
  // from OLD_SPACE here, like external_map or message_object_map, but currently
  // no one does so this check is sufficient.
  DCHECK(ReadOnlyHeap::Contains(map));
  Tagged<HeapObject> result = AllocateRaw(size, allocation, alignment, hint);
  DisallowGarbageCollection no_gc;
  result->set_map_after_allocation(isolate(), map, SKIP_WRITE_BARRIER);
  return result;
}

template <typename Impl>
Tagged<HeapObject> FactoryBase<Impl>::AllocateRaw(int size,
                                                  AllocationType allocation,
                                                  AllocationAlignment alignment,
                                                  AllocationHint hint) {
  return impl()->AllocateRaw(size, allocation, alignment, hint);
}

template <typename Impl>
Handle<SwissNameDictionary>
FactoryBase<Impl>::NewSwissNameDictionaryWithCapacity(
    int capacity, AllocationType allocation) {
  DCHECK(SwissNameDictionary::IsValidCapacity(capacity));

  if (capacity == 0) {
    DCHECK_NE(
        read_only_roots().address_at(RootIndex::kEmptySwissPropertyDictionary),
        kNullAddress);

    return empty_swiss_property_dictionary();
  }

  if (capacity < 0 || capacity > SwissNameDictionary::MaxCapacity()) {
    base::FatalNoSecurityImpact("Fatal JavaScript invalid size error %d",
                                capacity);
    UNREACHABLE();
  }

  int meta_table_length = SwissNameDictionary::MetaTableSizeFor(capacity);
  DirectHandle<ByteArray> meta_table =
      impl()->NewByteArray(meta_table_length, allocation);

  Tagged<Map> map = read_only_roots().swiss_name_dictionary_map();
  int size = SwissNameDictionary::SizeFor(capacity);
  Tagged<SwissNameDictionary> table = Cast<SwissNameDictionary>(
      AllocateRawWithImmortalMap(size, allocation, map));
  DisallowGarbageCollection no_gc;
  table->Initialize(isolate(), *meta_table, capacity);
  return handle(table, isolate());
}

template <typename Impl>
Handle<SwissNameDictionary> FactoryBase<Impl>::NewSwissNameDictionary(
    int at_least_space_for, AllocationType allocation) {
  return NewSwissNameDictionaryWithCapacity(
      SwissNameDictionary::CapacityFor(at_least_space_for), allocation);
}

template <typename Impl>
DirectHandle<FunctionTemplateRareData>
FactoryBase<Impl>::NewFunctionTemplateRareData() {
  auto function_template_rare_data =
      NewStructInternal<FunctionTemplateRareData>(
          FUNCTION_TEMPLATE_RARE_DATA_TYPE, AllocationType::kOld);
  DisallowGarbageCollection no_gc;
  function_template_rare_data->set_c_function_overloads(
      *impl()->empty_fixed_array(), SKIP_WRITE_BARRIER);
  return direct_handle(function_template_rare_data, isolate());
}

template <typename Impl>
MaybeDirectHandle<Map> FactoryBase<Impl>::GetInPlaceInternalizedStringMap(
    Tagged<Map> from_string_map) {
  InstanceType instance_type = from_string_map->instance_type();
  MaybeDirectHandle<Map> map;
  switch (instance_type) {
    case SEQ_TWO_BYTE_STRING_TYPE:
    case SHARED_SEQ_TWO_BYTE_STRING_TYPE:
      map = internalized_two_byte_string_map();
      break;
    case SEQ_ONE_BYTE_STRING_TYPE:
    case SHARED_SEQ_ONE_BYTE_STRING_TYPE:
      map = internalized_one_byte_string_map();
      break;
    case SHARED_EXTERNAL_TWO_BYTE_STRING_TYPE:
    case EXTERNAL_TWO_BYTE_STRING_TYPE:
      map = external_internalized_two_byte_string_map();
      break;
    case SHARED_EXTERNAL_ONE_BYTE_STRING_TYPE:
    case EXTERNAL_ONE_BYTE_STRING_TYPE:
      map = external_internalized_one_byte_string_map();
      break;
    default:
      break;
  }
  DCHECK_EQ(!map.is_null(), String::IsInPlaceInternalizable(instance_type));
  return map;
}

template <typename Impl>
AllocationType
FactoryBase<Impl>::RefineAllocationTypeForInPlaceInternalizableString(
    AllocationType allocation, Tagged<Map> string_map) {
#ifdef DEBUG
  InstanceType instance_type = string_map->instance_type();
  DCHECK(InstanceTypeChecker::IsInternalizedString(instance_type) ||
         String::IsInPlaceInternalizable(instance_type));
#endif
  if (v8_flags.single_generation && allocation == AllocationType::kYoung) {
    allocation = AllocationType::kOld;
  }
  if (allocation != AllocationType::kOld) return allocation;
  return impl()->AllocationTypeForInPlaceInternalizableString();
}

template <typename Impl>
JSDispatchHandle FactoryBase<Impl>::NewJSDispatchHandle(
    uint16_t parameter_count, DirectHandle<Code> code,
    JSDispatchTable::Space* space) {
  JSDispatchTable& jdt = isolate()->js_dispatch_table();
  auto result =
      jdt.TryAllocateAndInitializeEntry(space, parameter_count, *code);
  if (result) {
    return *result;
  }
  auto allocate_callback = [&]() {
    return (result = jdt.TryAllocateAndInitializeEntry(space, parameter_count,
                                                       *code))
        .has_value();
  };
  // Dispatch entries are only freed on major GCs.
  AllocationType type = AllocationType::kOld;
  auto allocator = isolate()->heap()->allocator();
  allocator->RetryCustomAllocateOrFail(allocate_callback, type);
  return *result;
}

// Instantiate FactoryBase for the two variants we want.
template class EXPORT_TEMPLATE_DEFINE(V8_EXPORT_PRIVATE) FactoryBase<Factory>;
template class EXPORT_TEMPLATE_DEFINE(V8_EXPORT_PRIVATE)
    FactoryBase<LocalFactory>;

template V8_EXPORT_PRIVATE MaybeIndirectHandle<String>
FactoryBase<Factory>::NewConsString(IndirectHandle<String> left,
                                    IndirectHandle<String> right,
                                    AllocationType allocation);
template V8_EXPORT_PRIVATE MaybeDirectHandle<String>
FactoryBase<Factory>::NewConsString(DirectHandle<String> left,
                                    DirectHandle<String> right,
                                    AllocationType allocation);
template V8_EXPORT_PRIVATE MaybeIndirectHandle<String>
FactoryBase<LocalFactory>::NewConsString(IndirectHandle<String> left,
                                         IndirectHandle<String> right,
                                         AllocationType allocation);
template V8_EXPORT_PRIVATE MaybeDirectHandle<String>
FactoryBase<LocalFactory>::NewConsString(DirectHandle<String> left,
                                         DirectHandle<String> right,
                                         AllocationType allocation);

}  // namespace internal
}  // namespace v8