src/objects/code-inl.h

// 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.

#ifndef V8_OBJECTS_CODE_INL_H_
#define V8_OBJECTS_CODE_INL_H_

#include "src/baseline/bytecode-offset-iterator.h"
#include "src/codegen/code-desc.h"
#include "src/heap/heap-write-barrier-inl.h"
#include "src/objects/code.h"
#include "src/objects/deoptimization-data-inl.h"
#include "src/objects/instance-type-inl.h"
#include "src/objects/instruction-stream-inl.h"
#include "src/objects/trusted-object-inl.h"
#include "src/snapshot/embedded/embedded-data-inl.h"

// Has to be the last include (doesn't have include guards):
#include "src/objects/object-macros.h"

namespace v8 {
namespace internal {

OBJECT_CONSTRUCTORS_IMPL(Code, ExposedTrustedObject)
OBJECT_CONSTRUCTORS_IMPL(GcSafeCode, HeapObject)

CAST_ACCESSOR(GcSafeCode)
CAST_ACCESSOR(Code)

Tagged<Code> GcSafeCode::UnsafeCastToCode() const {
  return Code::unchecked_cast(*this);
}

#define GCSAFE_CODE_FWD_ACCESSOR(ReturnType, Name) \
  ReturnType GcSafeCode::Name() const { return UnsafeCastToCode()->Name(); }
GCSAFE_CODE_FWD_ACCESSOR(Address, instruction_start)
GCSAFE_CODE_FWD_ACCESSOR(Address, instruction_end)
GCSAFE_CODE_FWD_ACCESSOR(bool, is_builtin)
GCSAFE_CODE_FWD_ACCESSOR(Builtin, builtin_id)
GCSAFE_CODE_FWD_ACCESSOR(CodeKind, kind)
GCSAFE_CODE_FWD_ACCESSOR(bool, is_interpreter_trampoline_builtin)
GCSAFE_CODE_FWD_ACCESSOR(bool, is_baseline_trampoline_builtin)
GCSAFE_CODE_FWD_ACCESSOR(bool, is_baseline_leave_frame_builtin)
GCSAFE_CODE_FWD_ACCESSOR(bool, has_instruction_stream)
GCSAFE_CODE_FWD_ACCESSOR(bool, is_maglevved)
GCSAFE_CODE_FWD_ACCESSOR(bool, is_turbofanned)
GCSAFE_CODE_FWD_ACCESSOR(bool, has_tagged_outgoing_params)
GCSAFE_CODE_FWD_ACCESSOR(bool, marked_for_deoptimization)
GCSAFE_CODE_FWD_ACCESSOR(Tagged<Object>, raw_instruction_stream)
GCSAFE_CODE_FWD_ACCESSOR(int, stack_slots)
GCSAFE_CODE_FWD_ACCESSOR(Address, constant_pool)
GCSAFE_CODE_FWD_ACCESSOR(Address, safepoint_table_address)
#undef GCSAFE_CODE_FWD_ACCESSOR

int GcSafeCode::GetOffsetFromInstructionStart(Isolate* isolate,
                                              Address pc) const {
  return UnsafeCastToCode()->GetOffsetFromInstructionStart(isolate, pc);
}

Address GcSafeCode::InstructionStart(Isolate* isolate, Address pc) const {
  return UnsafeCastToCode()->InstructionStart(isolate, pc);
}

Address GcSafeCode::InstructionEnd(Isolate* isolate, Address pc) const {
  return UnsafeCastToCode()->InstructionEnd(isolate, pc);
}

bool GcSafeCode::CanDeoptAt(Isolate* isolate, Address pc) const {
  if (!UnsafeCastToCode()->uses_deoptimization_data()) return false;
  Tagged<DeoptimizationData> deopt_data = DeoptimizationData::unchecked_cast(
      UnsafeCastToCode()->unchecked_deoptimization_data());
  Address code_start_address = instruction_start();
  for (int i = 0; i < deopt_data->DeoptCount(); i++) {
    if (deopt_data->Pc(i).value() == -1) continue;
    Address address = code_start_address + deopt_data->Pc(i).value();
    if (address == pc && deopt_data->GetBytecodeOffsetOrBuiltinContinuationId(
                             i) != BytecodeOffset::None()) {
      return true;
    }
  }
  return false;
}

Tagged<Object> GcSafeCode::raw_instruction_stream(
    PtrComprCageBase code_cage_base) const {
  return UnsafeCastToCode()->raw_instruction_stream(code_cage_base);
}

INT_ACCESSORS(Code, instruction_size, kInstructionSizeOffset)
INT_ACCESSORS(Code, metadata_size, kMetadataSizeOffset)
INT_ACCESSORS(Code, handler_table_offset, kHandlerTableOffsetOffset)
INT_ACCESSORS(Code, code_comments_offset, kCodeCommentsOffsetOffset)
INT32_ACCESSORS(Code, unwinding_info_offset, kUnwindingInfoOffsetOffset)
UINT16_ACCESSORS(Code, parameter_count, kParameterCountOffset)

inline Tagged<ProtectedFixedArray> Code::deoptimization_data() const {
  DCHECK(uses_deoptimization_data());
  return ProtectedFixedArray::cast(
      ReadProtectedPointerField(kDeoptimizationDataOrInterpreterDataOffset));
}

inline void Code::set_deoptimization_data(Tagged<ProtectedFixedArray> value,
                                          WriteBarrierMode mode) {
  DCHECK(uses_deoptimization_data());
  DCHECK(!ObjectInYoungGeneration(value));

  WriteProtectedPointerField(kDeoptimizationDataOrInterpreterDataOffset, value);
  CONDITIONAL_PROTECTED_POINTER_WRITE_BARRIER(
      *this, kDeoptimizationDataOrInterpreterDataOffset, value, mode);
}

inline bool Code::uses_deoptimization_data() const {
  return CodeKindUsesDeoptimizationData(kind());
}

inline void Code::clear_deoptimization_data_and_interpreter_data() {
  ClearProtectedPointerField(kDeoptimizationDataOrInterpreterDataOffset);
}

inline bool Code::has_deoptimization_data_or_interpreter_data() const {
  return !IsProtectedPointerFieldCleared(
      kDeoptimizationDataOrInterpreterDataOffset);
}

Tagged<TrustedObject> Code::bytecode_or_interpreter_data() const {
  DCHECK_EQ(kind(), CodeKind::BASELINE);
  return ReadProtectedPointerField(kDeoptimizationDataOrInterpreterDataOffset);
}
void Code::set_bytecode_or_interpreter_data(Tagged<TrustedObject> value,
                                            WriteBarrierMode mode) {
  DCHECK(kind() == CodeKind::BASELINE);
  DCHECK(IsBytecodeArray(value) || IsInterpreterData(value));

  WriteProtectedPointerField(kDeoptimizationDataOrInterpreterDataOffset, value);
  CONDITIONAL_PROTECTED_POINTER_WRITE_BARRIER(
      *this, kDeoptimizationDataOrInterpreterDataOffset, value, mode);
}

inline Tagged<TrustedByteArray> Code::source_position_table() const {
  DCHECK(has_source_position_table());
  return TrustedByteArray::cast(
      ReadProtectedPointerField(kPositionTableOffset));
}

inline void Code::set_source_position_table(Tagged<TrustedByteArray> value,
                                            WriteBarrierMode mode) {
  DCHECK(!CodeKindUsesBytecodeOffsetTable(kind()));

  WriteProtectedPointerField(kPositionTableOffset, value);
  CONDITIONAL_PROTECTED_POINTER_WRITE_BARRIER(*this, kPositionTableOffset,
                                              value, mode);
}

inline Tagged<TrustedByteArray> Code::bytecode_offset_table() const {
  DCHECK(has_bytecode_offset_table());
  return TrustedByteArray::cast(
      ReadProtectedPointerField(kPositionTableOffset));
}

inline void Code::set_bytecode_offset_table(Tagged<TrustedByteArray> value,
                                            WriteBarrierMode mode) {
  DCHECK(CodeKindUsesBytecodeOffsetTable(kind()));

  WriteProtectedPointerField(kPositionTableOffset, value);
  CONDITIONAL_PROTECTED_POINTER_WRITE_BARRIER(*this, kPositionTableOffset,
                                              value, mode);
}

bool Code::has_source_position_table_or_bytecode_offset_table() const {
  return TaggedField<Object, kPositionTableOffset>::load(*this) != Smi::zero();
}

bool Code::has_source_position_table() const {
  bool has_table = has_source_position_table_or_bytecode_offset_table() &&
                   !CodeKindUsesBytecodeOffsetTable(kind());
  DCHECK_IMPLIES(!CodeKindMayLackSourcePositionTable(kind()), has_table);
  return has_table;
}

bool Code::has_bytecode_offset_table() const {
  return has_source_position_table_or_bytecode_offset_table() &&
         CodeKindUsesBytecodeOffsetTable(kind());
}

void Code::clear_source_position_table_and_bytecode_offset_table() {
  TaggedField<Object, kPositionTableOffset>::store(*this, Smi::zero());
}

ACCESSORS(Code, wrapper, Tagged<CodeWrapper>, kWrapperOffset)

Tagged<TrustedByteArray> Code::SourcePositionTable(
    Isolate* isolate, Tagged<SharedFunctionInfo> sfi) const {
  DisallowGarbageCollection no_gc;

  if (kind() == CodeKind::BASELINE) {
    return sfi->GetBytecodeArray(isolate)->SourcePositionTable(isolate);
  }

  if (!has_source_position_table()) {
    return *isolate->factory()->empty_trusted_byte_array();
  }

  return source_position_table();
}

Address Code::body_start() const { return instruction_start(); }

Address Code::body_end() const { return body_start() + body_size(); }

int Code::body_size() const { return instruction_size() + metadata_size(); }

Address Code::instruction_end() const {
  return instruction_start() + instruction_size();
}

Address Code::metadata_start() const {
  if (has_instruction_stream()) {
    static_assert(InstructionStream::kOnHeapBodyIsContiguous);
    return instruction_start() + instruction_size();
  }
  // An embedded builtin. Remapping is irrelevant wrt the metadata section so
  // we can simply use the global blob.
  // TODO(jgruber): Consider adding this as a physical Code field to avoid the
  // lookup. Alternatively, rename this (and callers) to camel-case to clarify
  // it's more than a simple accessor.
  static_assert(!InstructionStream::kOffHeapBodyIsContiguous);
  return EmbeddedData::FromBlob().MetadataStartOf(builtin_id());
}

Address Code::InstructionStart(Isolate* isolate, Address pc) const {
  if (V8_LIKELY(has_instruction_stream())) return instruction_start();
  // Note we intentionally don't bounds-check that `pc` is within the returned
  // instruction area.
  return EmbeddedData::FromBlobForPc(isolate, pc)
      .InstructionStartOf(builtin_id());
}

Address Code::InstructionEnd(Isolate* isolate, Address pc) const {
  return InstructionStart(isolate, pc) + instruction_size();
}

int Code::GetOffsetFromInstructionStart(Isolate* isolate, Address pc) const {
  const Address offset = pc - InstructionStart(isolate, pc);
  DCHECK_LE(offset, instruction_size());
  return static_cast<int>(offset);
}

Address Code::metadata_end() const {
  return metadata_start() + metadata_size();
}

Address Code::safepoint_table_address() const {
  return metadata_start() + safepoint_table_offset();
}

int Code::safepoint_table_size() const {
  return handler_table_offset() - safepoint_table_offset();
}

bool Code::has_safepoint_table() const { return safepoint_table_size() > 0; }

Address Code::handler_table_address() const {
  return metadata_start() + handler_table_offset();
}

int Code::handler_table_size() const {
  return constant_pool_offset() - handler_table_offset();
}

bool Code::has_handler_table() const { return handler_table_size() > 0; }

int Code::constant_pool_size() const {
  const int size = code_comments_offset() - constant_pool_offset();
  if (!V8_EMBEDDED_CONSTANT_POOL_BOOL) {
    DCHECK_EQ(size, 0);
    return 0;
  }
  DCHECK_GE(size, 0);
  return size;
}

bool Code::has_constant_pool() const { return constant_pool_size() > 0; }

Tagged<ProtectedFixedArray> Code::unchecked_deoptimization_data() const {
  return ProtectedFixedArray::unchecked_cast(
      ReadProtectedPointerField(kDeoptimizationDataOrInterpreterDataOffset));
}

uint8_t* Code::relocation_start() const {
  return V8_LIKELY(has_instruction_stream())
             ? instruction_stream()->relocation_start()
             : nullptr;
}

uint8_t* Code::relocation_end() const {
  return V8_LIKELY(has_instruction_stream())
             ? instruction_stream()->relocation_end()
             : nullptr;
}

int Code::relocation_size() const {
  return V8_LIKELY(has_instruction_stream())
             ? instruction_stream()->relocation_size()
             : 0;
}

bool Code::contains(Isolate* isolate, Address inner_pointer) const {
  const Address start = InstructionStart(isolate, inner_pointer);
  if (inner_pointer < start) return false;
  return inner_pointer < start + instruction_size();
}

int Code::InstructionStreamObjectSize() const {
  return InstructionStream::SizeFor(body_size());
}

int Code::SizeIncludingMetadata() const {
  int size = InstructionStreamObjectSize();
  size += relocation_size();
  if (uses_deoptimization_data()) {
    size += deoptimization_data()->Size();
  }
  return size;
}

CodeKind Code::kind() const { return KindField::decode(flags(kRelaxedLoad)); }

int Code::GetBytecodeOffsetForBaselinePC(Address baseline_pc,
                                         Tagged<BytecodeArray> bytecodes) {
  DisallowGarbageCollection no_gc;
  CHECK(!is_baseline_trampoline_builtin());
  if (is_baseline_leave_frame_builtin()) return kFunctionExitBytecodeOffset;
  CHECK_EQ(kind(), CodeKind::BASELINE);
  baseline::BytecodeOffsetIterator offset_iterator(
      TrustedByteArray::cast(bytecode_offset_table()), bytecodes);
  Address pc = baseline_pc - instruction_start();
  offset_iterator.AdvanceToPCOffset(pc);
  return offset_iterator.current_bytecode_offset();
}

uintptr_t Code::GetBaselinePCForBytecodeOffset(
    int bytecode_offset, BytecodeToPCPosition position,
    Tagged<BytecodeArray> bytecodes) {
  DisallowGarbageCollection no_gc;
  CHECK_EQ(kind(), CodeKind::BASELINE);
  baseline::BytecodeOffsetIterator offset_iterator(
      TrustedByteArray::cast(bytecode_offset_table()), bytecodes);
  offset_iterator.AdvanceToBytecodeOffset(bytecode_offset);
  uintptr_t pc = 0;
  if (position == kPcAtStartOfBytecode) {
    pc = offset_iterator.current_pc_start_offset();
  } else {
    DCHECK_EQ(position, kPcAtEndOfBytecode);
    pc = offset_iterator.current_pc_end_offset();
  }
  return pc;
}

uintptr_t Code::GetBaselineStartPCForBytecodeOffset(
    int bytecode_offset, Tagged<BytecodeArray> bytecodes) {
  return GetBaselinePCForBytecodeOffset(bytecode_offset, kPcAtStartOfBytecode,
                                        bytecodes);
}

uintptr_t Code::GetBaselineEndPCForBytecodeOffset(
    int bytecode_offset, Tagged<BytecodeArray> bytecodes) {
  return GetBaselinePCForBytecodeOffset(bytecode_offset, kPcAtEndOfBytecode,
                                        bytecodes);
}

uintptr_t Code::GetBaselinePCForNextExecutedBytecode(
    int bytecode_offset, Tagged<BytecodeArray> bytecodes) {
  DisallowGarbageCollection no_gc;
  CHECK_EQ(kind(), CodeKind::BASELINE);
  baseline::BytecodeOffsetIterator offset_iterator(
      TrustedByteArray::cast(bytecode_offset_table()), bytecodes);
  Handle<BytecodeArray> bytecodes_handle(
      reinterpret_cast<Address*>(&bytecodes));
  interpreter::BytecodeArrayIterator bytecode_iterator(bytecodes_handle,
                                                       bytecode_offset);
  interpreter::Bytecode bytecode = bytecode_iterator.current_bytecode();
  if (bytecode == interpreter::Bytecode::kJumpLoop) {
    return GetBaselineStartPCForBytecodeOffset(
        bytecode_iterator.GetJumpTargetOffset(), bytecodes);
  } else {
    DCHECK(!interpreter::Bytecodes::IsJump(bytecode));
    DCHECK(!interpreter::Bytecodes::IsSwitch(bytecode));
    DCHECK(!interpreter::Bytecodes::Returns(bytecode));
    return GetBaselineEndPCForBytecodeOffset(bytecode_offset, bytecodes);
  }
}

inline bool Code::checks_tiering_state() const {
  bool checks_state = (builtin_id() == Builtin::kCompileLazy ||
                       builtin_id() == Builtin::kInterpreterEntryTrampoline ||
                       CodeKindCanTierUp(kind()));
  return checks_state ||
         (CodeKindCanDeoptimize(kind()) && marked_for_deoptimization());
}

inline constexpr bool CodeKindHasTaggedOutgoingParams(CodeKind kind) {
  return kind != CodeKind::JS_TO_WASM_FUNCTION &&
         kind != CodeKind::C_WASM_ENTRY && kind != CodeKind::WASM_FUNCTION;
}

inline bool Code::has_tagged_outgoing_params() const {
#if V8_ENABLE_WEBASSEMBLY
  return CodeKindHasTaggedOutgoingParams(kind()) &&
         builtin_id() != Builtin::kWasmCompileLazy;
#else
  return CodeKindHasTaggedOutgoingParams(kind());
#endif
}

inline bool Code::is_turbofanned() const {
  return IsTurbofannedField::decode(flags(kRelaxedLoad));
}

inline bool Code::is_maglevved() const { return kind() == CodeKind::MAGLEV; }

unsigned Code::inlined_bytecode_size() const {
  unsigned size = RELAXED_READ_UINT_FIELD(*this, kInlinedBytecodeSizeOffset);
  DCHECK(CodeKindIsOptimizedJSFunction(kind()) || size == 0);
  return size;
}

void Code::set_inlined_bytecode_size(unsigned size) {
  DCHECK(CodeKindIsOptimizedJSFunction(kind()) || size == 0);
  RELAXED_WRITE_UINT_FIELD(*this, kInlinedBytecodeSizeOffset, size);
}

BytecodeOffset Code::osr_offset() const {
  return BytecodeOffset(RELAXED_READ_INT32_FIELD(*this, kOsrOffsetOffset));
}

void Code::set_osr_offset(BytecodeOffset offset) {
  RELAXED_WRITE_INT32_FIELD(*this, kOsrOffsetOffset, offset.ToInt());
}

bool Code::uses_safepoint_table() const {
  return is_turbofanned() || is_maglevved() || is_wasm_code();
}

int Code::stack_slots() const {
  const int slots = StackSlotsField::decode(flags(kRelaxedLoad));
  DCHECK_IMPLIES(!uses_safepoint_table(), slots == 0);
  return slots;
}

bool Code::marked_for_deoptimization() const {
  return MarkedForDeoptimizationField::decode(flags(kRelaxedLoad));
}

void Code::set_marked_for_deoptimization(bool flag) {
  DCHECK_IMPLIES(flag, AllowDeoptimization::IsAllowed(
                           GetIsolateFromWritableObject(*this)));
  int32_t previous = flags(kRelaxedLoad);
  int32_t updated = MarkedForDeoptimizationField::update(previous, flag);
  set_flags(updated, kRelaxedStore);
}

bool Code::embedded_objects_cleared() const {
  return Code::EmbeddedObjectsClearedField::decode(flags(kRelaxedLoad));
}

void Code::set_embedded_objects_cleared(bool flag) {
  DCHECK_IMPLIES(flag, marked_for_deoptimization());
  int32_t previous = flags(kRelaxedLoad);
  int32_t updated = Code::EmbeddedObjectsClearedField::update(previous, flag);
  set_flags(updated, kRelaxedStore);
}

inline bool Code::can_have_weak_objects() const {
  return CanHaveWeakObjectsField::decode(flags(kRelaxedLoad));
}

inline void Code::set_can_have_weak_objects(bool value) {
  int32_t previous = flags(kRelaxedLoad);
  int32_t updated = CanHaveWeakObjectsField::update(previous, value);
  set_flags(updated, kRelaxedStore);
}

bool Code::is_wasm_code() const { return kind() == CodeKind::WASM_FUNCTION; }

int Code::constant_pool_offset() const {
  if (!V8_EMBEDDED_CONSTANT_POOL_BOOL) {
    // Redirection needed since the field doesn't exist in this case.
    return code_comments_offset();
  }
  return ReadField<int>(kConstantPoolOffsetOffset);
}

void Code::set_constant_pool_offset(int value) {
  if (!V8_EMBEDDED_CONSTANT_POOL_BOOL) {
    // Redirection needed since the field doesn't exist in this case.
    return;
  }
  DCHECK_LE(value, metadata_size());
  WriteField<int>(kConstantPoolOffsetOffset, value);
}

Address Code::constant_pool() const {
  if (!has_constant_pool()) return kNullAddress;
  return metadata_start() + constant_pool_offset();
}

Address Code::code_comments() const {
  return metadata_start() + code_comments_offset();
}

int Code::code_comments_size() const {
  return unwinding_info_offset() - code_comments_offset();
}

bool Code::has_code_comments() const { return code_comments_size() > 0; }

Address Code::unwinding_info_start() const {
  return metadata_start() + unwinding_info_offset();
}

Address Code::unwinding_info_end() const { return metadata_end(); }

int Code::unwinding_info_size() const {
  return static_cast<int>(unwinding_info_end() - unwinding_info_start());
}

bool Code::has_unwinding_info() const { return unwinding_info_size() > 0; }

// static
Tagged<Code> Code::FromTargetAddress(Address address) {
  return InstructionStream::FromTargetAddress(address)->code(kAcquireLoad);
}

bool Code::CanContainWeakObjects() {
  return is_optimized_code() && can_have_weak_objects();
}

bool Code::IsWeakObject(Tagged<HeapObject> object) {
  return (CanContainWeakObjects() && IsWeakObjectInOptimizedCode(object));
}

bool Code::IsWeakObjectInOptimizedCode(Tagged<HeapObject> object) {
  Tagged<Map> map_object = object->map(kAcquireLoad);
  if (InstanceTypeChecker::IsMap(map_object)) {
    return Map::cast(object)->CanTransition();
  }
  return InstanceTypeChecker::IsPropertyCell(map_object) ||
         InstanceTypeChecker::IsJSReceiver(map_object) ||
         InstanceTypeChecker::IsContext(map_object);
}

bool Code::IsWeakObjectInDeoptimizationLiteralArray(Tagged<Object> object) {
  // Maps must be strong because they can be used as part of the description for
  // how to materialize an object upon deoptimization, in which case it is
  // possible to reach the code that requires the Map without anything else
  // holding a strong pointer to that Map.
  return IsHeapObject(object) && !IsMap(object) &&
         Code::IsWeakObjectInOptimizedCode(HeapObject::cast(object));
}

void Code::IterateDeoptimizationLiterals(RootVisitor* v) {
  if (!uses_deoptimization_data()) {
    DCHECK(kind() == CodeKind::BASELINE ||
           !has_deoptimization_data_or_interpreter_data());
    return;
  }

  auto deopt_data = DeoptimizationData::cast(deoptimization_data());
  if (deopt_data->length() == 0) return;

  Tagged<DeoptimizationLiteralArray> literals = deopt_data->LiteralArray();
  const int literals_length = literals->length();
  for (int i = 0; i < literals_length; ++i) {
    Tagged<MaybeObject> maybe_literal = literals->get_raw(i);
    Tagged<HeapObject> heap_literal;
    if (maybe_literal.GetHeapObject(&heap_literal)) {
      v->VisitRootPointer(Root::kStackRoots, "deoptimization literal",
                          FullObjectSlot(&heap_literal));
    }
  }
}

Tagged<Object> Code::raw_instruction_stream() const {
  PtrComprCageBase cage_base = code_cage_base();
  return Code::raw_instruction_stream(cage_base);
}

Tagged<Object> Code::raw_instruction_stream(PtrComprCageBase cage_base) const {
  return ExternalCodeField<Object>::load(cage_base, *this);
}

void Code::set_raw_instruction_stream(Tagged<Object> value,
                                      WriteBarrierMode mode) {
  ExternalCodeField<Object>::Release_Store(*this, value);
  CONDITIONAL_WRITE_BARRIER(*this, kInstructionStreamOffset, value, mode);
}

bool Code::has_instruction_stream() const {
#if defined(V8_COMPRESS_POINTERS) || !defined(V8_HOST_ARCH_64_BIT)
  const uint32_t value = ReadField<uint32_t>(kInstructionStreamOffset);
#else
  const uint64_t value = ReadField<uint64_t>(kInstructionStreamOffset);
#endif
  SLOW_DCHECK(value == 0 || !InReadOnlySpace(*this));
  return value != 0;
}

bool Code::has_instruction_stream(RelaxedLoadTag tag) const {
#if defined(V8_COMPRESS_POINTERS) || !defined(V8_HOST_ARCH_64_BIT)
  const uint32_t value =
      RELAXED_READ_INT32_FIELD(*this, kInstructionStreamOffset);
#else
  const uint64_t value =
      RELAXED_READ_INT64_FIELD(*this, kInstructionStreamOffset);
#endif
  SLOW_DCHECK(value == 0 || !InReadOnlySpace(*this));
  return value != 0;
}

PtrComprCageBase Code::code_cage_base() const {
#ifdef V8_EXTERNAL_CODE_SPACE
  return PtrComprCageBase(ExternalCodeCompressionScheme::base());
#else   // V8_EXTERNAL_CODE_SPACE
  // Without external code space: `code_cage_base == main_cage_base`. We can
  // get the main cage base from any heap object, including objects in RO
  // space.
  return GetPtrComprCageBase(*this);
#endif  // V8_EXTERNAL_CODE_SPACE
}

Tagged<InstructionStream> Code::instruction_stream() const {
  PtrComprCageBase cage_base = code_cage_base();
  return Code::instruction_stream(cage_base);
}

Tagged<InstructionStream> Code::unchecked_instruction_stream() const {
  return InstructionStream::unchecked_cast(raw_instruction_stream());
}

Tagged<InstructionStream> Code::instruction_stream(
    PtrComprCageBase cage_base) const {
  DCHECK(has_instruction_stream());
  return ExternalCodeField<InstructionStream>::load(cage_base, *this);
}

Tagged<InstructionStream> Code::instruction_stream(RelaxedLoadTag tag) const {
  PtrComprCageBase cage_base = code_cage_base();
  return Code::instruction_stream(cage_base, tag);
}

Tagged<InstructionStream> Code::instruction_stream(PtrComprCageBase cage_base,
                                                   RelaxedLoadTag tag) const {
  DCHECK(has_instruction_stream());
  return ExternalCodeField<InstructionStream>::Relaxed_Load(cage_base, *this);
}

Tagged<Object> Code::raw_instruction_stream(RelaxedLoadTag tag) const {
  PtrComprCageBase cage_base = code_cage_base();
  return Code::raw_instruction_stream(cage_base, tag);
}

Tagged<Object> Code::raw_instruction_stream(PtrComprCageBase cage_base,
                                            RelaxedLoadTag tag) const {
  return ExternalCodeField<Object>::Relaxed_Load(cage_base, *this);
}

DEF_GETTER(Code, instruction_start, Address) {
#ifdef V8_ENABLE_SANDBOX
  return ReadCodeEntrypointViaCodePointerField(kSelfIndirectPointerOffset,
                                               entrypoint_tag());
#else
  return ReadField<Address>(kInstructionStartOffset);
#endif
}

void Code::set_instruction_start(IsolateForSandbox isolate, Address value) {
#ifdef V8_ENABLE_SANDBOX
  WriteCodeEntrypointViaCodePointerField(kSelfIndirectPointerOffset, value,
                                         entrypoint_tag());
#else
  WriteField<Address>(kInstructionStartOffset, value);
#endif
}

CodeEntrypointTag Code::entrypoint_tag() const {
  switch (kind()) {
    case CodeKind::BYTECODE_HANDLER:
      return kBytecodeHandlerEntrypointTag;
    case CodeKind::BUILTIN:
      return Builtins::EntrypointTagFor(builtin_id());
    case CodeKind::REGEXP:
      return kRegExpEntrypointTag;
    case CodeKind::WASM_FUNCTION:
    case CodeKind::WASM_TO_CAPI_FUNCTION:
    case CodeKind::WASM_TO_JS_FUNCTION:
      return kWasmEntrypointTag;
    case CodeKind::JS_TO_WASM_FUNCTION:
      return kJSEntrypointTag;
    default:
      // TODO(saelo): eventually we'll want this to be UNREACHABLE().
      return kDefaultCodeEntrypointTag;
  }
}

void Code::SetInstructionStreamAndInstructionStart(
    IsolateForSandbox isolate, Tagged<InstructionStream> code,
    WriteBarrierMode mode) {
  set_raw_instruction_stream(code, mode);
  set_instruction_start(isolate, code->instruction_start());
}

void Code::SetInstructionStartForOffHeapBuiltin(IsolateForSandbox isolate,
                                                Address entry) {
  DCHECK(!has_instruction_stream());
  set_instruction_start(isolate, entry);
}

void Code::ClearInstructionStartForSerialization(IsolateForSandbox isolate) {
#ifdef V8_ENABLE_SANDBOX
  // The instruction start is stored in this object's code pointer table.
  WriteField<CodePointerHandle>(kSelfIndirectPointerOffset,
                                kNullCodePointerHandle);
#else
  set_instruction_start(isolate, kNullAddress);
#endif  // V8_ENABLE_SANDBOX
}

void Code::UpdateInstructionStart(IsolateForSandbox isolate,
                                  Tagged<InstructionStream> istream) {
  DCHECK_EQ(raw_instruction_stream(), istream);
  set_instruction_start(isolate, istream->instruction_start());
}

void Code::clear_padding() {
  memset(reinterpret_cast<void*>(address() + kUnalignedSize), 0,
         kSize - kUnalignedSize);
}

RELAXED_UINT32_ACCESSORS(Code, flags, kFlagsOffset)

void Code::initialize_flags(CodeKind kind, bool is_turbofanned,
                            int stack_slots) {
  CHECK(0 <= stack_slots && stack_slots < StackSlotsField::kMax);
  DCHECK(!CodeKindIsInterpretedJSFunction(kind));
  uint32_t value = KindField::encode(kind) |
                   IsTurbofannedField::encode(is_turbofanned) |
                   StackSlotsField::encode(stack_slots);
  static_assert(FIELD_SIZE(kFlagsOffset) == kInt32Size);
  set_flags(value, kRelaxedStore);
  DCHECK_IMPLIES(stack_slots != 0, uses_safepoint_table());
  DCHECK_IMPLIES(!uses_safepoint_table(), stack_slots == 0);
}

// Ensure builtin_id field fits into int16_t, so that we can rely on sign
// extension to convert int16_t{-1} to kNoBuiltinId.
// If the asserts fail, update the code that use kBuiltinIdOffset below.
static_assert(static_cast<int>(Builtin::kNoBuiltinId) == -1);
static_assert(Builtins::kBuiltinCount < std::numeric_limits<int16_t>::max());

void Code::set_builtin_id(Builtin builtin_id) {
  static_assert(FIELD_SIZE(kBuiltinIdOffset) == kInt16Size);
  Relaxed_WriteField<int16_t>(kBuiltinIdOffset,
                              static_cast<int16_t>(builtin_id));
}

Builtin Code::builtin_id() const {
  // Rely on sign-extension when converting int16_t to int to preserve
  // kNoBuiltinId value.
  static_assert(FIELD_SIZE(kBuiltinIdOffset) == kInt16Size);
  static_assert(static_cast<int>(static_cast<int16_t>(Builtin::kNoBuiltinId)) ==
                static_cast<int>(Builtin::kNoBuiltinId));
  int value = ReadField<int16_t>(kBuiltinIdOffset);
  return static_cast<Builtin>(value);
}

bool Code::is_builtin() const { return builtin_id() != Builtin::kNoBuiltinId; }

bool Code::is_optimized_code() const {
  return CodeKindIsOptimizedJSFunction(kind());
}

inline bool Code::is_interpreter_trampoline_builtin() const {
  return IsInterpreterTrampolineBuiltin(builtin_id());
}

inline bool Code::is_baseline_trampoline_builtin() const {
  return IsBaselineTrampolineBuiltin(builtin_id());
}

inline bool Code::is_baseline_leave_frame_builtin() const {
  return builtin_id() == Builtin::kBaselineLeaveFrame;
}

CAST_ACCESSOR(CodeWrapper)
OBJECT_CONSTRUCTORS_IMPL(CodeWrapper, Struct)
CODE_POINTER_ACCESSORS(CodeWrapper, code, kCodeOffset)

}  // namespace internal
}  // namespace v8

#include "src/objects/object-macros-undef.h"

#endif  // V8_OBJECTS_CODE_INL_H_