runtime/vm/object.cc

// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

#include "vm/object.h"

#include <memory>

#include "compiler/method_recognizer.h"
#include "include/dart_api.h"
#include "lib/integers.h"
#include "lib/stacktrace.h"
#include "platform/assert.h"
#include "platform/text_buffer.h"
#include "platform/unaligned.h"
#include "platform/unicode.h"
#include "vm/bit_vector.h"
#include "vm/bootstrap.h"
#include "vm/bytecode_reader.h"
#include "vm/canonical_tables.h"
#include "vm/class_finalizer.h"
#include "vm/class_id.h"
#include "vm/closure_functions_cache.h"
#include "vm/code_comments.h"
#include "vm/code_descriptors.h"
#include "vm/code_observers.h"
#include "vm/compiler/assembler/disassembler.h"
#include "vm/compiler/assembler/disassembler_kbc.h"
#include "vm/compiler/jit/compiler.h"
#include "vm/compiler/runtime_api.h"
#include "vm/cpu.h"
#include "vm/dart.h"
#include "vm/dart_api_state.h"
#include "vm/dart_entry.h"
#include "vm/datastream.h"
#include "vm/debugger.h"
#include "vm/deopt_instructions.h"
#include "vm/double_conversion.h"
#include "vm/elf.h"
#include "vm/exceptions.h"
#include "vm/growable_array.h"
#include "vm/hash.h"
#include "vm/hash_table.h"
#include "vm/heap/become.h"
#include "vm/heap/heap.h"
#include "vm/heap/sampler.h"
#include "vm/heap/weak_code.h"
#include "vm/image_snapshot.h"
#include "vm/isolate_reload.h"
#include "vm/kernel.h"
#include "vm/kernel_binary.h"
#include "vm/kernel_isolate.h"
#include "vm/kernel_loader.h"
#include "vm/log.h"
#include "vm/native_symbol.h"
#include "vm/object_graph.h"
#include "vm/object_store.h"
#include "vm/os.h"
#include "vm/parser.h"
#include "vm/profiler.h"
#include "vm/regexp/regexp.h"
#include "vm/resolver.h"
#include "vm/reusable_handles.h"
#include "vm/reverse_pc_lookup_cache.h"
#include "vm/runtime_entry.h"
#include "vm/scopes.h"
#include "vm/stack_frame.h"
#include "vm/stub_code.h"
#include "vm/symbols.h"
#include "vm/tags.h"
#include "vm/thread_registry.h"
#include "vm/timeline.h"
#include "vm/type_testing_stubs.h"
#include "vm/zone_text_buffer.h"

#if !defined(DART_PRECOMPILED_RUNTIME)
#include "vm/compiler/aot/precompiler.h"
#include "vm/compiler/assembler/assembler.h"
#include "vm/compiler/backend/code_statistics.h"
#include "vm/compiler/compiler_state.h"
#include "vm/compiler/frontend/kernel_fingerprints.h"
#include "vm/compiler/frontend/kernel_translation_helper.h"
#include "vm/compiler/intrinsifier.h"
#endif  // !defined(DART_PRECOMPILED_RUNTIME)

namespace dart {

DEFINE_FLAG(uint64_t,
            huge_method_cutoff_in_code_size,
            200000,
            "Huge method cutoff in unoptimized code size (in bytes).");
DEFINE_FLAG(
    bool,
    show_internal_names,
    false,
    "Show names of internal classes (e.g. \"OneByteString\") in error messages "
    "instead of showing the corresponding interface names (e.g. \"String\"). "
    "Also show legacy nullability in type names.");

DEFINE_FLAG(bool,
            remove_script_timestamps_for_test,
            false,
            "Remove script timestamps to allow for deterministic testing.");

#if !defined(DART_PRECOMPILED_RUNTIME)
DEFINE_FLAG(bool, use_register_cc, true, "Use register calling conventions");
#endif

DECLARE_FLAG(bool, intrinsify);
DECLARE_FLAG(bool, trace_deoptimization);
DECLARE_FLAG(bool, trace_deoptimization_verbose);
DECLARE_FLAG(bool, trace_reload);
DECLARE_FLAG(bool, write_protect_code);
DECLARE_FLAG(bool, precompiled_mode);
DECLARE_FLAG(int, max_polymorphic_checks);

static const char* const kGetterPrefix = "get:";
static const intptr_t kGetterPrefixLength = strlen(kGetterPrefix);
static const char* const kSetterPrefix = "set:";
static const intptr_t kSetterPrefixLength = strlen(kSetterPrefix);
static const char* const kInitPrefix = "init:";
static const intptr_t kInitPrefixLength = strlen(kInitPrefix);

// A cache of VM heap allocated preinitialized empty ic data entry arrays.
ArrayPtr ICData::cached_icdata_arrays_[kCachedICDataArrayCount];

cpp_vtable Object::builtin_vtables_[kNumPredefinedCids] = {};

// These are initialized to a value that will force an illegal memory access if
// they are being used.
#if defined(RAW_NULL)
#error RAW_NULL should not be defined.
#endif
#define RAW_NULL static_cast<uword>(kHeapObjectTag)

#define CHECK_ERROR(error)                                                     \
  {                                                                            \
    ErrorPtr err = (error);                                                    \
    if (err != Error::null()) {                                                \
      return err;                                                              \
    }                                                                          \
  }

#define DEFINE_SHARED_READONLY_HANDLE(Type, name)                              \
  Type* Object::name##_ = nullptr;
SHARED_READONLY_HANDLES_LIST(DEFINE_SHARED_READONLY_HANDLE)
#undef DEFINE_SHARED_READONLY_HANDLE

ObjectPtr Object::null_ = static_cast<ObjectPtr>(RAW_NULL);
BoolPtr Object::true_ = static_cast<BoolPtr>(RAW_NULL);
BoolPtr Object::false_ = static_cast<BoolPtr>(RAW_NULL);
ClassPtr Object::class_class_ = static_cast<ClassPtr>(RAW_NULL);
ClassPtr Object::dynamic_class_ = static_cast<ClassPtr>(RAW_NULL);
ClassPtr Object::void_class_ = static_cast<ClassPtr>(RAW_NULL);
ClassPtr Object::type_parameters_class_ = static_cast<ClassPtr>(RAW_NULL);
ClassPtr Object::type_arguments_class_ = static_cast<ClassPtr>(RAW_NULL);
ClassPtr Object::patch_class_class_ = static_cast<ClassPtr>(RAW_NULL);
ClassPtr Object::function_class_ = static_cast<ClassPtr>(RAW_NULL);
ClassPtr Object::closure_data_class_ = static_cast<ClassPtr>(RAW_NULL);
ClassPtr Object::ffi_trampoline_data_class_ = static_cast<ClassPtr>(RAW_NULL);
ClassPtr Object::field_class_ = static_cast<ClassPtr>(RAW_NULL);
ClassPtr Object::script_class_ = static_cast<ClassPtr>(RAW_NULL);
ClassPtr Object::library_class_ = static_cast<ClassPtr>(RAW_NULL);
ClassPtr Object::namespace_class_ = static_cast<ClassPtr>(RAW_NULL);
ClassPtr Object::kernel_program_info_class_ = static_cast<ClassPtr>(RAW_NULL);
ClassPtr Object::code_class_ = static_cast<ClassPtr>(RAW_NULL);
ClassPtr Object::instructions_class_ = static_cast<ClassPtr>(RAW_NULL);
ClassPtr Object::instructions_section_class_ = static_cast<ClassPtr>(RAW_NULL);
ClassPtr Object::instructions_table_class_ = static_cast<ClassPtr>(RAW_NULL);
ClassPtr Object::object_pool_class_ = static_cast<ClassPtr>(RAW_NULL);
ClassPtr Object::pc_descriptors_class_ = static_cast<ClassPtr>(RAW_NULL);
ClassPtr Object::code_source_map_class_ = static_cast<ClassPtr>(RAW_NULL);
ClassPtr Object::compressed_stackmaps_class_ = static_cast<ClassPtr>(RAW_NULL);
ClassPtr Object::var_descriptors_class_ = static_cast<ClassPtr>(RAW_NULL);
ClassPtr Object::exception_handlers_class_ = static_cast<ClassPtr>(RAW_NULL);
ClassPtr Object::context_class_ = static_cast<ClassPtr>(RAW_NULL);
ClassPtr Object::context_scope_class_ = static_cast<ClassPtr>(RAW_NULL);
ClassPtr Object::bytecode_class_ = static_cast<ClassPtr>(RAW_NULL);
ClassPtr Object::sentinel_class_ = static_cast<ClassPtr>(RAW_NULL);
ClassPtr Object::singletargetcache_class_ = static_cast<ClassPtr>(RAW_NULL);
ClassPtr Object::unlinkedcall_class_ = static_cast<ClassPtr>(RAW_NULL);
ClassPtr Object::monomorphicsmiablecall_class_ =
    static_cast<ClassPtr>(RAW_NULL);
ClassPtr Object::icdata_class_ = static_cast<ClassPtr>(RAW_NULL);
ClassPtr Object::megamorphic_cache_class_ = static_cast<ClassPtr>(RAW_NULL);
ClassPtr Object::subtypetestcache_class_ = static_cast<ClassPtr>(RAW_NULL);
ClassPtr Object::loadingunit_class_ = static_cast<ClassPtr>(RAW_NULL);
ClassPtr Object::api_error_class_ = static_cast<ClassPtr>(RAW_NULL);
ClassPtr Object::language_error_class_ = static_cast<ClassPtr>(RAW_NULL);
ClassPtr Object::unhandled_exception_class_ = static_cast<ClassPtr>(RAW_NULL);
ClassPtr Object::unwind_error_class_ = static_cast<ClassPtr>(RAW_NULL);
ClassPtr Object::weak_serialization_reference_class_ =
    static_cast<ClassPtr>(RAW_NULL);
ClassPtr Object::weak_array_class_ = static_cast<ClassPtr>(RAW_NULL);

static void AppendSubString(BaseTextBuffer* buffer,
                            const char* name,
                            intptr_t start_pos,
                            intptr_t len) {
  buffer->Printf("%.*s", static_cast<int>(len), &name[start_pos]);
}

// Used to define setters and getters for untagged object fields that are
// defined with the WSR_COMPRESSED_POINTER_FIELD macro. See
// PRECOMPILER_WSR_FIELD_DECLARATION in object.h for more information.
#if defined(DART_PRECOMPILER)
#define PRECOMPILER_WSR_FIELD_DEFINITION(Class, Type, Name)                    \
  Type##Ptr Class::Name() const {                                              \
    return Type::RawCast(WeakSerializationReference::Unwrap(untag()->Name())); \
  }
#else
#define PRECOMPILER_WSR_FIELD_DEFINITION(Class, Type, Name)                    \
  void Class::set_##Name(const Type& value) const {                            \
    untag()->set_##Name(value.ptr());                                          \
  }
#endif

PRECOMPILER_WSR_FIELD_DEFINITION(ClosureData, Function, parent_function)
PRECOMPILER_WSR_FIELD_DEFINITION(Function, FunctionType, signature)

#undef PRECOMPILER_WSR_FIELD_DEFINITION

#if defined(_MSC_VER)
#define TRACE_TYPE_CHECKS_VERBOSE(format, ...)                                 \
  if (FLAG_trace_type_checks_verbose) {                                        \
    OS::PrintErr(format, __VA_ARGS__);                                         \
  }
#else
#define TRACE_TYPE_CHECKS_VERBOSE(format, ...)                                 \
  if (FLAG_trace_type_checks_verbose) {                                        \
    OS::PrintErr(format, ##__VA_ARGS__);                                       \
  }
#endif

// Remove private keys, but retain getter/setter/constructor/mixin manglings.
StringPtr String::RemovePrivateKey(const String& name) {
  ASSERT(name.IsOneByteString());
  GrowableArray<uint8_t> without_key(name.Length());
  intptr_t i = 0;
  while (i < name.Length()) {
    while (i < name.Length()) {
      uint8_t c = name.CharAt(i++);
      if (c == '@') break;
      without_key.Add(c);
    }
    while (i < name.Length()) {
      uint8_t c = name.CharAt(i);
      if ((c < '0') || (c > '9')) break;
      i++;
    }
  }

  return String::FromLatin1(without_key.data(), without_key.length());
}

// Takes a vm internal name and makes it suitable for external user.
//
// Examples:
//
// Internal getter and setter prefixes are changed:
//
//   get:foo -> foo
//   set:foo -> foo=
//
// Private name mangling is removed, possibly multiple times:
//
//   _ReceivePortImpl@709387912 -> _ReceivePortImpl
//   _ReceivePortImpl@709387912._internal@709387912 ->
//      _ReceivePortImpl._internal
//   _C@6328321&_E@6328321&_F@6328321 -> _C&_E&_F
//
// The trailing . on the default constructor name is dropped:
//
//   List. -> List
//
// And so forth:
//
//   get:foo@6328321 -> foo
//   _MyClass@6328321. -> _MyClass
//   _MyClass@6328321.named -> _MyClass.named
//
// For extension methods the following demangling is done
//   ext|func -> ext.func (instance extension method)
//   ext|get#prop -> ext.prop (instance extension getter)
//   ext|set#prop -> ext.prop= (instance extension setter)
//   ext|sfunc -> ext.sfunc (static extension method)
//   get:ext|sprop -> ext.sprop (static extension getter)
//   set:ext|sprop -> ext.sprop= (static extension setter)
//
const char* String::ScrubName(const String& name, bool is_extension) {
  Thread* thread = Thread::Current();
  NoSafepointScope no_safepoint(thread);
  Zone* zone = thread->zone();
  ZoneTextBuffer printer(zone);

#if !defined(DART_PRECOMPILED_RUNTIME)
  if (name.Equals(Symbols::TopLevel())) {
    // Name of invisible top-level class.
    return "";
  }
#endif  // !defined(DART_PRECOMPILED_RUNTIME)

  const char* cname = name.ToCString();
  ASSERT(strlen(cname) == static_cast<size_t>(name.Length()));
  const intptr_t name_len = name.Length();
  // First remove all private name mangling and if 'is_extension' is true
  // substitute the first '|' character with '.'.
  intptr_t start_pos = 0;
  intptr_t sum_segment_len = 0;
  for (intptr_t i = 0; i < name_len; i++) {
    if ((cname[i] == '@') && ((i + 1) < name_len) && (cname[i + 1] >= '0') &&
        (cname[i + 1] <= '9')) {
      // Append the current segment to the unmangled name.
      const intptr_t segment_len = i - start_pos;
      sum_segment_len += segment_len;
      AppendSubString(&printer, cname, start_pos, segment_len);
      // Advance until past the name mangling. The private keys are only
      // numbers so we skip until the first non-number.
      i++;  // Skip the '@'.
      while ((i < name.Length()) && (name.CharAt(i) >= '0') &&
             (name.CharAt(i) <= '9')) {
        i++;
      }
      start_pos = i;
      i--;  // Account for for-loop increment.
    } else if (is_extension && cname[i] == '|') {
      // Append the current segment to the unmangled name.
      const intptr_t segment_len = i - start_pos;
      AppendSubString(&printer, cname, start_pos, segment_len);
      // Append the '.' character (replaces '|' with '.').
      AppendSubString(&printer, ".", 0, 1);
      start_pos = i + 1;
      // Account for length of segments added so far.
      sum_segment_len += (segment_len + 1);
    }
  }

  const char* unmangled_name = nullptr;
  if (start_pos == 0) {
    // No name unmangling needed, reuse the name that was passed in.
    unmangled_name = cname;
    sum_segment_len = name_len;
  } else if (name.Length() != start_pos) {
    // Append the last segment.
    const intptr_t segment_len = name.Length() - start_pos;
    sum_segment_len += segment_len;
    AppendSubString(&printer, cname, start_pos, segment_len);
  }
  if (unmangled_name == nullptr) {
    // Merge unmangled_segments.
    unmangled_name = printer.buffer();
  }

  printer.Clear();
  intptr_t start = 0;
  intptr_t len = sum_segment_len;
  bool is_setter = false;
  if (is_extension) {
    // First scan till we see the '.' character.
    for (intptr_t i = 0; i < len; i++) {
      if (unmangled_name[i] == '.') {
        intptr_t slen = i + 1;
        intptr_t plen = slen - start;
        AppendSubString(&printer, unmangled_name, start, plen);
        unmangled_name += slen;
        len -= slen;
        break;
      } else if (unmangled_name[i] == ':') {
        if (start != 0) {
          // Reset and break.
          start = 0;
          is_setter = false;
          break;
        }
        if (unmangled_name[0] == 's') {
          is_setter = true;
        }
        start = i + 1;
      }
    }
  }
  intptr_t dot_pos = -1;  // Position of '.' in the name, if any.
  start = 0;
  for (intptr_t i = start; i < len; i++) {
    if (unmangled_name[i] == ':' ||
        (is_extension && unmangled_name[i] == '#')) {
      if (start != 0) {
        // Reset and break.
        start = 0;
        dot_pos = -1;
        break;
      }
      ASSERT(start == 0);  // Only one : is possible in getters or setters.
      if (unmangled_name[0] == 's') {
        ASSERT(!is_setter);
        is_setter = true;
      }
      start = i + 1;
    } else if (unmangled_name[i] == '.') {
      if (dot_pos != -1) {
        // Reset and break.
        start = 0;
        dot_pos = -1;
        break;
      }
      ASSERT(dot_pos == -1);  // Only one dot is supported.
      dot_pos = i;
    }
  }

  if (!is_extension && (start == 0) && (dot_pos == -1)) {
    // This unmangled_name is fine as it is.
    return unmangled_name;
  }

  // Drop the trailing dot if needed.
  intptr_t end = ((dot_pos + 1) == len) ? dot_pos : len;

  intptr_t substr_len = end - start;
  AppendSubString(&printer, unmangled_name, start, substr_len);
  if (is_setter) {
    const char* equals = Symbols::Equals().ToCString();
    const intptr_t equals_len = strlen(equals);
    AppendSubString(&printer, equals, 0, equals_len);
  }

  return printer.buffer();
}

StringPtr String::ScrubNameRetainPrivate(const String& name,
                                         bool is_extension) {
#if !defined(DART_PRECOMPILED_RUNTIME)
  intptr_t len = name.Length();
  intptr_t start = 0;
  intptr_t at_pos = -1;  // Position of '@' in the name, if any.
  bool is_setter = false;

  String& result = String::Handle();

  // If extension strip out the leading prefix e.g" ext|func would strip out
  // 'ext|'.
  if (is_extension) {
    // First scan till we see the '|' character.
    for (intptr_t i = 0; i < len; i++) {
      if (name.CharAt(i) == '|') {
        result = String::SubString(name, start, (i - start));
        result = String::Concat(result, Symbols::Dot());
        start = i + 1;
        break;
      } else if (name.CharAt(i) == ':') {
        if (start != 0) {
          // Reset and break.
          start = 0;
          is_setter = false;
          break;
        }
        if (name.CharAt(0) == 's') {
          is_setter = true;
        }
        start = i + 1;
      }
    }
  }

  for (intptr_t i = start; i < len; i++) {
    if (name.CharAt(i) == ':' || (is_extension && name.CharAt(i) == '#')) {
      // Only one : is possible in getters or setters.
      ASSERT(is_extension || start == 0);
      if (name.CharAt(start) == 's') {
        is_setter = true;
      }
      start = i + 1;
    } else if (name.CharAt(i) == '@') {
      // Setters should have only one @ so we know where to put the =.
      ASSERT(!is_setter || (at_pos == -1));
      at_pos = i;
    }
  }

  if (start == 0) {
    // This unmangled_name is fine as it is.
    return name.ptr();
  }

  if (is_extension) {
    const String& fname =
        String::Handle(String::SubString(name, start, (len - start)));
    result = String::Concat(result, fname);
  } else {
    result = String::SubString(name, start, (len - start));
  }

  if (is_setter) {
    // Setters need to end with '='.
    if (at_pos == -1) {
      return String::Concat(result, Symbols::Equals());
    } else {
      const String& pre_at =
          String::Handle(String::SubString(result, 0, at_pos - 4));
      const String& post_at =
          String::Handle(String::SubString(name, at_pos, len - at_pos));
      result = String::Concat(pre_at, Symbols::Equals());
      result = String::Concat(result, post_at);
    }
  }

  return result.ptr();
#endif                // !defined(DART_PRECOMPILED_RUNTIME)
  return name.ptr();  // In AOT, return argument unchanged.
}

template <typename type>
static bool IsSpecialCharacter(type value) {
  return ((value == '"') || (value == '\n') || (value == '\f') ||
          (value == '\b') || (value == '\t') || (value == '\v') ||
          (value == '\r') || (value == '\\') || (value == '$'));
}

static inline bool IsAsciiNonprintable(int32_t c) {
  return ((0 <= c) && (c < 32)) || (c == 127);
}

static int32_t EscapeOverhead(int32_t c) {
  if (IsSpecialCharacter(c)) {
    return 1;  // 1 additional byte for the backslash.
  } else if (IsAsciiNonprintable(c)) {
    return 3;  // 3 additional bytes to encode c as \x00.
  }
  return 0;
}

template <typename type>
static type SpecialCharacter(type value) {
  if (value == '"') {
    return '"';
  } else if (value == '\n') {
    return 'n';
  } else if (value == '\f') {
    return 'f';
  } else if (value == '\b') {
    return 'b';
  } else if (value == '\t') {
    return 't';
  } else if (value == '\v') {
    return 'v';
  } else if (value == '\r') {
    return 'r';
  } else if (value == '\\') {
    return '\\';
  } else if (value == '$') {
    return '$';
  }
  UNREACHABLE();
  return '\0';
}

#if defined(DART_DYNAMIC_MODULES)
static BytecodePtr CreateVMInternalBytecode(KernelBytecode::Opcode opcode) {
  const KBCInstr* instructions = nullptr;
  intptr_t instructions_size = 0;

  KernelBytecode::GetVMInternalBytecodeInstructions(opcode, &instructions,
                                                    &instructions_size);

  const auto& bytecode = Bytecode::Handle(
      Bytecode::New(reinterpret_cast<uword>(instructions), instructions_size,
                    -1, TypedDataBase::Handle(), Object::empty_object_pool()));
  bytecode.set_pc_descriptors(Object::empty_descriptors());
  bytecode.set_exception_handlers(Object::empty_exception_handlers());
  return bytecode.ptr();
}
#endif  // defined(DART_DYNAMIC_MODULES)

void Object::InitNullAndBool(IsolateGroup* isolate_group) {
  // Should only be run by the vm isolate.
  ASSERT(isolate_group == Dart::vm_isolate_group());
  Thread* thread = Thread::Current();
  auto heap = isolate_group->heap();

  // TODO(iposva): NoSafepointScope needs to be added here.
  ASSERT(class_class() == null_);

  // Allocate and initialize the null instance.
  // 'null_' must be the first object allocated as it is used in allocation to
  // clear the pointer fields of objects.
  {
    uword address =
        heap->Allocate(thread, Instance::InstanceSize(), Heap::kOld);
    null_ = static_cast<InstancePtr>(address + kHeapObjectTag);
    InitializeObjectVariant<Instance>(address, kNullCid);
    null_->untag()->SetCanonical();
  }

  // Allocate and initialize the bool instances.
  // These must be allocated such that at kBoolValueBitPosition, the address
  // of true is 0 and the address of false is 1, and their addresses are
  // otherwise identical.
  {
    // Allocate a dummy bool object to give true the desired alignment.
    uword address = heap->Allocate(thread, Bool::InstanceSize(), Heap::kOld);
    InitializeObject<Bool>(address);
    static_cast<BoolPtr>(address + kHeapObjectTag)->untag()->value_ = false;
  }
  {
    // Allocate true.
    uword address = heap->Allocate(thread, Bool::InstanceSize(), Heap::kOld);
    true_ = static_cast<BoolPtr>(address + kHeapObjectTag);
    InitializeObject<Bool>(address);
    true_->untag()->value_ = true;
    true_->untag()->SetCanonical();
  }
  {
    // Allocate false.
    uword address = heap->Allocate(thread, Bool::InstanceSize(), Heap::kOld);
    false_ = static_cast<BoolPtr>(address + kHeapObjectTag);
    InitializeObject<Bool>(address);
    false_->untag()->value_ = false;
    false_->untag()->SetCanonical();
  }

  // Check that the objects have been allocated at appropriate addresses.
  ASSERT(static_cast<uword>(true_) ==
         static_cast<uword>(null_) + kTrueOffsetFromNull);
  ASSERT(static_cast<uword>(false_) ==
         static_cast<uword>(null_) + kFalseOffsetFromNull);
  ASSERT((static_cast<uword>(true_) & kBoolValueMask) == 0);
  ASSERT((static_cast<uword>(false_) & kBoolValueMask) != 0);
  ASSERT(static_cast<uword>(false_) ==
         (static_cast<uword>(true_) | kBoolValueMask));
  ASSERT((static_cast<uword>(null_) & kBoolVsNullMask) == 0);
  ASSERT((static_cast<uword>(true_) & kBoolVsNullMask) != 0);
  ASSERT((static_cast<uword>(false_) & kBoolVsNullMask) != 0);
}

void Object::InitVtables() {
  {
    Object fake_handle;
    builtin_vtables_[kObjectCid] = fake_handle.vtable();
  }

#define INIT_VTABLE(clazz)                                                     \
  {                                                                            \
    clazz fake_handle;                                                         \
    builtin_vtables_[k##clazz##Cid] = fake_handle.vtable();                    \
  }
  CLASS_LIST_NO_OBJECT_NOR_STRING_NOR_ARRAY_NOR_MAP(INIT_VTABLE)
  INIT_VTABLE(GrowableObjectArray)
#undef INIT_VTABLE

#define INIT_VTABLE(clazz)                                                     \
  {                                                                            \
    Map fake_handle;                                                           \
    builtin_vtables_[k##clazz##Cid] = fake_handle.vtable();                    \
  }
  CLASS_LIST_MAPS(INIT_VTABLE)
#undef INIT_VTABLE

#define INIT_VTABLE(clazz)                                                     \
  {                                                                            \
    Set fake_handle;                                                           \
    builtin_vtables_[k##clazz##Cid] = fake_handle.vtable();                    \
  }
  CLASS_LIST_SETS(INIT_VTABLE)
#undef INIT_VTABLE

#define INIT_VTABLE(clazz)                                                     \
  {                                                                            \
    Array fake_handle;                                                         \
    builtin_vtables_[k##clazz##Cid] = fake_handle.vtable();                    \
  }
  CLASS_LIST_FIXED_LENGTH_ARRAYS(INIT_VTABLE)
#undef INIT_VTABLE

#define INIT_VTABLE(clazz)                                                     \
  {                                                                            \
    String fake_handle;                                                        \
    builtin_vtables_[k##clazz##Cid] = fake_handle.vtable();                    \
  }
  CLASS_LIST_STRINGS(INIT_VTABLE)
#undef INIT_VTABLE

  {
    Instance fake_handle;
    builtin_vtables_[kFfiNativeTypeCid] = fake_handle.vtable();
  }

#define INIT_VTABLE(clazz)                                                     \
  {                                                                            \
    Instance fake_handle;                                                      \
    builtin_vtables_[kFfi##clazz##Cid] = fake_handle.vtable();                 \
  }
  CLASS_LIST_FFI_TYPE_MARKER(INIT_VTABLE)
#undef INIT_VTABLE

  {
    Instance fake_handle;
    builtin_vtables_[kFfiNativeFunctionCid] = fake_handle.vtable();
  }

  {
    Pointer fake_handle;
    builtin_vtables_[kPointerCid] = fake_handle.vtable();
  }

  {
    DynamicLibrary fake_handle;
    builtin_vtables_[kDynamicLibraryCid] = fake_handle.vtable();
  }

#define INIT_VTABLE(clazz)                                                     \
  {                                                                            \
    TypedData fake_internal_handle;                                            \
    builtin_vtables_[kTypedData##clazz##Cid] = fake_internal_handle.vtable();  \
    TypedDataView fake_view_handle;                                            \
    builtin_vtables_[kTypedData##clazz##ViewCid] = fake_view_handle.vtable();  \
    builtin_vtables_[kUnmodifiableTypedData##clazz##ViewCid] =                 \
        fake_view_handle.vtable();                                             \
    ExternalTypedData fake_external_handle;                                    \
    builtin_vtables_[kExternalTypedData##clazz##Cid] =                         \
        fake_external_handle.vtable();                                         \
  }
  CLASS_LIST_TYPED_DATA(INIT_VTABLE)
#undef INIT_VTABLE

  {
    TypedDataView fake_handle;
    builtin_vtables_[kByteDataViewCid] = fake_handle.vtable();
    builtin_vtables_[kUnmodifiableByteDataViewCid] = fake_handle.vtable();
  }

  {
    Instance fake_handle;
    builtin_vtables_[kByteBufferCid] = fake_handle.vtable();
    builtin_vtables_[kNullCid] = fake_handle.vtable();
    builtin_vtables_[kDynamicCid] = fake_handle.vtable();
    builtin_vtables_[kVoidCid] = fake_handle.vtable();
    builtin_vtables_[kNeverCid] = fake_handle.vtable();
  }
}

void Object::Init(IsolateGroup* isolate_group) {
  // Should only be run by the vm isolate.
  ASSERT(isolate_group == Dart::vm_isolate_group());
  Heap* heap = isolate_group->heap();
  Thread* thread = Thread::Current();
  ASSERT(thread != nullptr);
  // Ensure lock checks in setters are happy.
  SafepointWriteRwLocker ml(thread, isolate_group->program_lock());

  InitVtables();

// Allocate the read only object handles here.
#define INITIALIZE_SHARED_READONLY_HANDLE(Type, name)                          \
  name##_ = Type::ReadOnlyHandle();
  SHARED_READONLY_HANDLES_LIST(INITIALIZE_SHARED_READONLY_HANDLE)
#undef INITIALIZE_SHARED_READONLY_HANDLE

  *null_object_ = Object::null();
  *null_class_ = Class::null();
  *null_array_ = Array::null();
  *null_string_ = String::null();
  *null_instance_ = Instance::null();
  *null_function_ = Function::null();
  *null_function_type_ = FunctionType::null();
  *null_record_type_ = RecordType::null();
  *null_type_arguments_ = TypeArguments::null();
  *null_closure_ = Closure::null();
  *empty_type_arguments_ = TypeArguments::null();
  *null_abstract_type_ = AbstractType::null();
  *null_compressed_stackmaps_ = CompressedStackMaps::null();
  *bool_true_ = true_;
  *bool_false_ = false_;

  // Initialize the empty array and empty instantiations cache array handles to
  // null_ in order to be able to check if the empty and zero arrays were
  // allocated (RAW_NULL is not available).
  *empty_array_ = Array::null();
  *empty_instantiations_cache_array_ = Array::null();
  *empty_subtype_test_cache_array_ = Array::null();

  Class& cls = Class::Handle();

  // Allocate and initialize the class class.
  {
    intptr_t size = Class::InstanceSize();
    uword address = heap->Allocate(thread, size, Heap::kOld);
    class_class_ = static_cast<ClassPtr>(address + kHeapObjectTag);
    InitializeObject<Class>(address);

    Class fake;
    // Initialization from Class::New<Class>.
    // Directly set ptr_ to break a circular dependency: SetRaw will attempt
    // to lookup class class in the class table where it is not registered yet.
    cls.ptr_ = class_class_;
    ASSERT(builtin_vtables_[kClassCid] == fake.vtable());
    cls.set_instance_size(
        Class::InstanceSize(),
        compiler::target::RoundedAllocationSize(RTN::Class::InstanceSize()));
    const intptr_t host_next_field_offset = Class::NextFieldOffset();
    const intptr_t target_next_field_offset = RTN::Class::NextFieldOffset();
    cls.set_next_field_offset(host_next_field_offset, target_next_field_offset);
    cls.set_id(Class::kClassId);
    cls.set_state_bits(0);
    cls.set_is_allocate_finalized();
    cls.set_is_declaration_loaded();
    cls.set_is_type_finalized();
    cls.set_type_arguments_field_offset_in_words(Class::kNoTypeArguments,
                                                 RTN::Class::kNoTypeArguments);
    cls.set_num_type_arguments_unsafe(0);
    cls.set_num_native_fields(0);
    cls.InitEmptyFields();
    isolate_group->class_table()->Register(cls);
  }

  // Allocate and initialize the null class.
  cls = Class::New<Instance, RTN::Instance>(kNullCid, isolate_group);
  cls.set_num_type_arguments_unsafe(0);
  isolate_group->object_store()->set_null_class(cls);

  // Allocate and initialize Never class.
  cls = Class::New<Instance, RTN::Instance>(kNeverCid, isolate_group);
  cls.set_num_type_arguments_unsafe(0);
  cls.set_is_allocate_finalized();
  cls.set_is_declaration_loaded();
  cls.set_is_type_finalized();
  isolate_group->object_store()->set_never_class(cls);

  // Allocate and initialize the free list element class.
  cls = Class::New<FreeListElement::FakeInstance,
                   RTN::FreeListElement::FakeInstance>(kFreeListElement,
                                                       isolate_group);
  cls.set_num_type_arguments_unsafe(0);
  cls.set_is_allocate_finalized();
  cls.set_is_declaration_loaded();
  cls.set_is_type_finalized();

  // Allocate and initialize the forwarding corpse class.
  cls = Class::New<ForwardingCorpse::FakeInstance,
                   RTN::ForwardingCorpse::FakeInstance>(kForwardingCorpse,
                                                        isolate_group);
  cls.set_num_type_arguments_unsafe(0);
  cls.set_is_allocate_finalized();
  cls.set_is_declaration_loaded();
  cls.set_is_type_finalized();

  // Allocate and initialize Sentinel class.
  cls = Class::New<Sentinel, RTN::Sentinel>(isolate_group);
  sentinel_class_ = cls.ptr();

  // Allocate and initialize the sentinel values.
  {
    *sentinel_ ^= Sentinel::New();
  }

  // Allocate and initialize optimizing compiler constants.
  {
    *unknown_constant_ ^= Sentinel::New();
    *non_constant_ ^= Sentinel::New();
    *optimized_out_ ^= Sentinel::New();
  }

  // Allocate the remaining VM internal classes.
  cls = Class::New<TypeParameters, RTN::TypeParameters>(isolate_group);
  type_parameters_class_ = cls.ptr();

  cls = Class::New<TypeArguments, RTN::TypeArguments>(isolate_group);
  type_arguments_class_ = cls.ptr();

  cls = Class::New<PatchClass, RTN::PatchClass>(isolate_group);
  patch_class_class_ = cls.ptr();

  cls = Class::New<Function, RTN::Function>(isolate_group);
  function_class_ = cls.ptr();

  cls = Class::New<ClosureData, RTN::ClosureData>(isolate_group);
  closure_data_class_ = cls.ptr();

  cls = Class::New<FfiTrampolineData, RTN::FfiTrampolineData>(isolate_group);
  ffi_trampoline_data_class_ = cls.ptr();

  cls = Class::New<Field, RTN::Field>(isolate_group);
  field_class_ = cls.ptr();

  cls = Class::New<Script, RTN::Script>(isolate_group);
  script_class_ = cls.ptr();

  cls = Class::New<Library, RTN::Library>(isolate_group);
  library_class_ = cls.ptr();

  cls = Class::New<Namespace, RTN::Namespace>(isolate_group);
  namespace_class_ = cls.ptr();

  cls = Class::New<KernelProgramInfo, RTN::KernelProgramInfo>(isolate_group);
  kernel_program_info_class_ = cls.ptr();

  cls = Class::New<Code, RTN::Code>(isolate_group);
  code_class_ = cls.ptr();

  cls = Class::New<Instructions, RTN::Instructions>(isolate_group);
  instructions_class_ = cls.ptr();

  cls =
      Class::New<InstructionsSection, RTN::InstructionsSection>(isolate_group);
  instructions_section_class_ = cls.ptr();

  cls = Class::New<InstructionsTable, RTN::InstructionsTable>(isolate_group);
  instructions_table_class_ = cls.ptr();

  cls = Class::New<ObjectPool, RTN::ObjectPool>(isolate_group);
  object_pool_class_ = cls.ptr();

  cls = Class::New<PcDescriptors, RTN::PcDescriptors>(isolate_group);
  pc_descriptors_class_ = cls.ptr();

  cls = Class::New<CodeSourceMap, RTN::CodeSourceMap>(isolate_group);
  code_source_map_class_ = cls.ptr();

  cls =
      Class::New<CompressedStackMaps, RTN::CompressedStackMaps>(isolate_group);
  compressed_stackmaps_class_ = cls.ptr();

  cls =
      Class::New<LocalVarDescriptors, RTN::LocalVarDescriptors>(isolate_group);
  var_descriptors_class_ = cls.ptr();

  cls = Class::New<ExceptionHandlers, RTN::ExceptionHandlers>(isolate_group);
  exception_handlers_class_ = cls.ptr();

  cls = Class::New<Context, RTN::Context>(isolate_group);
  context_class_ = cls.ptr();

  cls = Class::New<ContextScope, RTN::ContextScope>(isolate_group);
  context_scope_class_ = cls.ptr();

  cls = Class::New<Bytecode, RTN::Bytecode>(isolate_group);
  bytecode_class_ = cls.ptr();

  cls = Class::New<SingleTargetCache, RTN::SingleTargetCache>(isolate_group);
  singletargetcache_class_ = cls.ptr();

  cls = Class::New<UnlinkedCall, RTN::UnlinkedCall>(isolate_group);
  unlinkedcall_class_ = cls.ptr();

  cls = Class::New<MonomorphicSmiableCall, RTN::MonomorphicSmiableCall>(
      isolate_group);
  monomorphicsmiablecall_class_ = cls.ptr();

  cls = Class::New<ICData, RTN::ICData>(isolate_group);
  icdata_class_ = cls.ptr();

  cls = Class::New<MegamorphicCache, RTN::MegamorphicCache>(isolate_group);
  megamorphic_cache_class_ = cls.ptr();

  cls = Class::New<SubtypeTestCache, RTN::SubtypeTestCache>(isolate_group);
  subtypetestcache_class_ = cls.ptr();

  cls = Class::New<LoadingUnit, RTN::LoadingUnit>(isolate_group);
  loadingunit_class_ = cls.ptr();

  cls = Class::New<ApiError, RTN::ApiError>(isolate_group);
  api_error_class_ = cls.ptr();

  cls = Class::New<LanguageError, RTN::LanguageError>(isolate_group);
  language_error_class_ = cls.ptr();

  cls = Class::New<UnhandledException, RTN::UnhandledException>(isolate_group);
  unhandled_exception_class_ = cls.ptr();

  cls = Class::New<UnwindError, RTN::UnwindError>(isolate_group);
  unwind_error_class_ = cls.ptr();

  cls = Class::New<WeakSerializationReference, RTN::WeakSerializationReference>(
      isolate_group);
  weak_serialization_reference_class_ = cls.ptr();

  cls = Class::New<WeakArray, RTN::WeakArray>(isolate_group);
  weak_array_class_ = cls.ptr();

  ASSERT(class_class() != null_);

  // Pre-allocate classes in the vm isolate so that we can for example create a
  // symbol table and populate it with some frequently used strings as symbols.
  cls = Class::New<Array, RTN::Array>(isolate_group);
  isolate_group->object_store()->set_array_class(cls);
  cls.set_type_arguments_field_offset(Array::type_arguments_offset(),
                                      RTN::Array::type_arguments_offset());
  cls.set_num_type_arguments_unsafe(1);
  cls = Class::New<Array, RTN::Array>(kImmutableArrayCid, isolate_group);
  isolate_group->object_store()->set_immutable_array_class(cls);
  cls.set_type_arguments_field_offset(Array::type_arguments_offset(),
                                      RTN::Array::type_arguments_offset());
  cls.set_num_type_arguments_unsafe(1);
  // In order to be able to canonicalize arguments descriptors early.
  cls.set_is_prefinalized();
  cls =
      Class::New<GrowableObjectArray, RTN::GrowableObjectArray>(isolate_group);
  isolate_group->object_store()->set_growable_object_array_class(cls);
  cls.set_type_arguments_field_offset(
      GrowableObjectArray::type_arguments_offset(),
      RTN::GrowableObjectArray::type_arguments_offset());
  cls.set_num_type_arguments_unsafe(1);
  cls = Class::NewStringClass(kOneByteStringCid, isolate_group);
  isolate_group->object_store()->set_one_byte_string_class(cls);
  cls = Class::NewStringClass(kTwoByteStringCid, isolate_group);
  isolate_group->object_store()->set_two_byte_string_class(cls);
  cls = Class::New<Mint, RTN::Mint>(isolate_group);
  isolate_group->object_store()->set_mint_class(cls);
  cls = Class::New<Double, RTN::Double>(isolate_group);
  isolate_group->object_store()->set_double_class(cls);
  cls = Class::New<Float32x4, RTN::Float32x4>(isolate_group);
  isolate_group->object_store()->set_float32x4_class(cls);
  cls = Class::New<Float64x2, RTN::Float64x2>(isolate_group);
  isolate_group->object_store()->set_float64x2_class(cls);
  cls = Class::New<Int32x4, RTN::Int32x4>(isolate_group);
  isolate_group->object_store()->set_int32x4_class(cls);

  // Ensure that class kExternalTypedDataUint8ArrayCid is registered as we
  // need it when reading in the token stream of bootstrap classes in the VM
  // isolate.
  Class::NewExternalTypedDataClass(kExternalTypedDataUint8ArrayCid,
                                   isolate_group);

  // Needed for object pools of VM isolate stubs.
  Class::NewTypedDataClass(kTypedDataInt8ArrayCid, isolate_group);

  // Allocate and initialize the empty_array instance.
  {
    uword address = heap->Allocate(thread, Array::InstanceSize(0), Heap::kOld);
    InitializeObjectVariant<Array>(address, kImmutableArrayCid, 0);
    Array::initializeHandle(empty_array_,
                            static_cast<ArrayPtr>(address + kHeapObjectTag));
    empty_array_->untag()->set_length(Smi::New(0));
    empty_array_->SetCanonical();
  }

  Smi& smi = Smi::Handle();
  // Allocate and initialize the empty instantiations cache array instance,
  // which contains metadata as the first element and a sentinel value
  // at the start of the first entry.
  {
    const intptr_t array_size =
        static_cast<intptr_t>(TypeArguments::Cache::kHeaderSize) +
        static_cast<intptr_t>(TypeArguments::Cache::kEntrySize);
    uword address =
        heap->Allocate(thread, Array::InstanceSize(array_size), Heap::kOld);
    InitializeObjectVariant<Array>(address, kImmutableArrayCid, array_size);
    Array::initializeHandle(empty_instantiations_cache_array_,
                            static_cast<ArrayPtr>(address + kHeapObjectTag));
    empty_instantiations_cache_array_->untag()->set_length(
        Smi::New(array_size));
    // The empty cache has no occupied entries and is not a hash-based cache.
    smi = Smi::New(0);
    empty_instantiations_cache_array_->SetAt(
        TypeArguments::Cache::kMetadataIndex, smi);
    // Make the first (and only) entry unoccupied by setting its first element
    // to the sentinel value.
    smi = TypeArguments::Cache::Sentinel();
    InstantiationsCacheTable table(*empty_instantiations_cache_array_);
    table.At(0).Set<TypeArguments::Cache::kSentinelIndex>(smi);
    // The other contents of the array are immaterial.
    empty_instantiations_cache_array_->SetCanonical();
  }

  // Allocate and initialize the empty subtype test cache array instance,
  // which contains a single unoccupied entry.
  {
    const intptr_t array_size = SubtypeTestCache::kTestEntryLength;
    uword address =
        heap->Allocate(thread, Array::InstanceSize(array_size), Heap::kOld);
    InitializeObjectVariant<Array>(address, kImmutableArrayCid, array_size);
    Array::initializeHandle(empty_subtype_test_cache_array_,
                            static_cast<ArrayPtr>(address + kHeapObjectTag));
    empty_subtype_test_cache_array_->untag()->set_length(Smi::New(array_size));
    // Make the first (and only) entry unoccupied by setting its first element
    // to the null value.
    empty_subtype_test_cache_array_->SetAt(
        SubtypeTestCache::kInstanceCidOrSignature, Object::null_object());
    smi = TypeArguments::Cache::Sentinel();
    SubtypeTestCacheTable table(*empty_subtype_test_cache_array_);
    table.At(0).Set<SubtypeTestCache::kInstanceCidOrSignature>(
        Object::null_object());
    // The other contents of the array are immaterial.
    empty_subtype_test_cache_array_->SetCanonical();
  }

  // Allocate and initialize the canonical empty context scope object.
  {
    uword address =
        heap->Allocate(thread, ContextScope::InstanceSize(0), Heap::kOld);
    InitializeObject<ContextScope>(address, 0);
    ContextScope::initializeHandle(
        empty_context_scope_,
        static_cast<ContextScopePtr>(address + kHeapObjectTag));
    empty_context_scope_->StoreNonPointer(
        &empty_context_scope_->untag()->num_variables_, 0);
    empty_context_scope_->StoreNonPointer(
        &empty_context_scope_->untag()->is_implicit_, true);
    empty_context_scope_->SetCanonical();
  }

  // Allocate and initialize the canonical empty object pool object.
  {
    uword address =
        heap->Allocate(thread, ObjectPool::InstanceSize(0), Heap::kOld);
    InitializeObject<ObjectPool>(address, 0);
    ObjectPool::initializeHandle(
        empty_object_pool_,
        static_cast<ObjectPoolPtr>(address + kHeapObjectTag));
    empty_object_pool_->StoreNonPointer(&empty_object_pool_->untag()->length_,
                                        0);
    empty_object_pool_->SetCanonical();
  }

  // Allocate and initialize the empty_compressed_stackmaps instance.
  {
    const intptr_t instance_size = CompressedStackMaps::InstanceSize(0);
    uword address = heap->Allocate(thread, instance_size, Heap::kOld);
    InitializeObject<CompressedStackMaps>(address, 0);
    CompressedStackMaps::initializeHandle(
        empty_compressed_stackmaps_,
        static_cast<CompressedStackMapsPtr>(address + kHeapObjectTag));
    empty_compressed_stackmaps_->untag()->payload()->set_flags_and_size(0);
    empty_compressed_stackmaps_->SetCanonical();
  }

  // Allocate and initialize the empty_descriptors instance.
  {
    uword address =
        heap->Allocate(thread, PcDescriptors::InstanceSize(0), Heap::kOld);
    InitializeObject<PcDescriptors>(address, 0);
    PcDescriptors::initializeHandle(
        empty_descriptors_,
        static_cast<PcDescriptorsPtr>(address + kHeapObjectTag));
    empty_descriptors_->StoreNonPointer(&empty_descriptors_->untag()->length_,
                                        0);
    empty_descriptors_->SetCanonical();
  }

  // Allocate and initialize the canonical empty variable descriptor object.
  {
    uword address = heap->Allocate(thread, LocalVarDescriptors::InstanceSize(0),
                                   Heap::kOld);
    InitializeObject<LocalVarDescriptors>(address, 0);
    LocalVarDescriptors::initializeHandle(
        empty_var_descriptors_,
        static_cast<LocalVarDescriptorsPtr>(address + kHeapObjectTag));
    empty_var_descriptors_->StoreNonPointer(
        &empty_var_descriptors_->untag()->num_entries_, 0);
    empty_var_descriptors_->SetCanonical();
  }

  // Allocate and initialize the canonical empty exception handler info object.
  // The vast majority of all functions do not contain an exception handler
  // and can share this canonical descriptor.
  {
    uword address =
        heap->Allocate(thread, ExceptionHandlers::InstanceSize(0), Heap::kOld);
    InitializeObject<ExceptionHandlers>(address, 0);
    ExceptionHandlers::initializeHandle(
        empty_exception_handlers_,
        static_cast<ExceptionHandlersPtr>(address + kHeapObjectTag));
    empty_exception_handlers_->StoreNonPointer(
        &empty_exception_handlers_->untag()->packed_fields_, 0);
    empty_exception_handlers_->SetCanonical();
  }

  // Empty exception handlers for async/async* functions.
  {
    uword address =
        heap->Allocate(thread, ExceptionHandlers::InstanceSize(0), Heap::kOld);
    InitializeObject<ExceptionHandlers>(address, 0);
    ExceptionHandlers::initializeHandle(
        empty_async_exception_handlers_,
        static_cast<ExceptionHandlersPtr>(address + kHeapObjectTag));
    empty_async_exception_handlers_->StoreNonPointer(
        &empty_async_exception_handlers_->untag()->packed_fields_,
        UntaggedExceptionHandlers::AsyncHandlerBit::update(true, 0));
    empty_async_exception_handlers_->SetCanonical();
  }

  // Allocate and initialize the canonical empty type arguments object.
  {
    uword address =
        heap->Allocate(thread, TypeArguments::InstanceSize(0), Heap::kOld);
    InitializeObject<TypeArguments>(address, 0);
    TypeArguments::initializeHandle(
        empty_type_arguments_,
        static_cast<TypeArgumentsPtr>(address + kHeapObjectTag));
    empty_type_arguments_->untag()->set_length(Smi::New(0));
    empty_type_arguments_->untag()->set_hash(Smi::New(0));
    empty_type_arguments_->ComputeHash();
    empty_type_arguments_->SetCanonical();
  }

  // The VM isolate snapshot object table is initialized to an empty array
  // as we do not have any VM isolate snapshot at this time.
  *vm_isolate_snapshot_object_table_ = Object::empty_array().ptr();

  cls = Class::New<Instance, RTN::Instance>(kDynamicCid, isolate_group);
  cls.set_is_abstract();
  cls.set_num_type_arguments_unsafe(0);
  cls.set_is_allocate_finalized();
  cls.set_is_declaration_loaded();
  cls.set_is_type_finalized();
  dynamic_class_ = cls.ptr();

  cls = Class::New<Instance, RTN::Instance>(kVoidCid, isolate_group);
  cls.set_num_type_arguments_unsafe(0);
  cls.set_is_allocate_finalized();
  cls.set_is_declaration_loaded();
  cls.set_is_type_finalized();
  void_class_ = cls.ptr();

  cls = Class::New<Type, RTN::Type>(isolate_group);
  cls.set_is_allocate_finalized();
  cls.set_is_declaration_loaded();
  cls.set_is_type_finalized();

  cls = Class::New<FunctionType, RTN::FunctionType>(isolate_group);
  cls.set_is_allocate_finalized();
  cls.set_is_declaration_loaded();
  cls.set_is_type_finalized();

  cls = Class::New<RecordType, RTN::RecordType>(isolate_group);
  cls.set_is_allocate_finalized();
  cls.set_is_declaration_loaded();
  cls.set_is_type_finalized();

  cls = dynamic_class_;
  *dynamic_type_ =
      Type::New(cls, Object::null_type_arguments(), Nullability::kNullable);
  dynamic_type_->SetIsFinalized();
  dynamic_type_->ComputeHash();
  dynamic_type_->SetCanonical();

  cls = void_class_;
  *void_type_ =
      Type::New(cls, Object::null_type_arguments(), Nullability::kNullable);
  void_type_->SetIsFinalized();
  void_type_->ComputeHash();
  void_type_->SetCanonical();

  // Since TypeArguments objects are passed as function arguments, make them
  // behave as Dart instances, although they are just VM objects.
  // Note that we cannot set the super type to ObjectType, which does not live
  // in the vm isolate. See special handling in Class::SuperClass().
  cls = type_arguments_class_;
  cls.set_interfaces(Object::empty_array());
  cls.SetFields(Object::empty_array());
  cls.SetFunctions(Object::empty_array());

  cls = Class::New<Bool, RTN::Bool>(isolate_group);
  isolate_group->object_store()->set_bool_class(cls);

  *smi_illegal_cid_ = Smi::New(kIllegalCid);
  *smi_zero_ = Smi::New(0);

  String& error_str = String::Handle();
  error_str = String::New(
      "Callbacks into the Dart VM are currently prohibited. Either there are "
      "outstanding pointers from Dart_TypedDataAcquireData that have not been "
      "released with Dart_TypedDataReleaseData, or a finalizer is running.",
      Heap::kOld);
  *no_callbacks_error_ = ApiError::New(error_str, Heap::kOld);
  error_str = String::New(
      "No api calls are allowed while unwind is in progress", Heap::kOld);
  *unwind_in_progress_error_ = UnwindError::New(error_str, Heap::kOld);
  error_str = String::New("SnapshotWriter Error", Heap::kOld);
  *snapshot_writer_error_ =
      LanguageError::New(error_str, Report::kError, Heap::kOld);
  error_str = String::New("Branch offset overflow", Heap::kOld);
  *branch_offset_error_ =
      LanguageError::New(error_str, Report::kBailout, Heap::kOld);
  error_str = String::New("Background Compilation Failed", Heap::kOld);
  *background_compilation_error_ =
      LanguageError::New(error_str, Report::kBailout, Heap::kOld);
  error_str = String::New("No debuggable code where breakpoint was requested",
                          Heap::kOld);
  *no_debuggable_code_error_ =
      LanguageError::New(error_str, Report::kError, Heap::kOld);
  error_str = String::New("Out of memory", Heap::kOld);
  *out_of_memory_error_ =
      LanguageError::New(error_str, Report::kError, Heap::kOld);

  // Allocate the parameter types and names for synthetic getters.
  *synthetic_getter_parameter_types_ = Array::New(1, Heap::kOld);
  synthetic_getter_parameter_types_->SetAt(0, Object::dynamic_type());
  *synthetic_getter_parameter_names_ = Array::New(1, Heap::kOld);
  // Fill in synthetic_getter_parameter_names_ later, after symbols are
  // initialized (in Object::FinalizeVMIsolate).
  // synthetic_getter_parameter_names_ object needs to be created earlier as
  // VM isolate snapshot reader references it before Object::FinalizeVMIsolate.

#if defined(DART_DYNAMIC_MODULES)
  *implicit_getter_bytecode_ =
      CreateVMInternalBytecode(KernelBytecode::kVMInternal_ImplicitGetter);

  *implicit_setter_bytecode_ =
      CreateVMInternalBytecode(KernelBytecode::kVMInternal_ImplicitSetter);

  *implicit_static_getter_bytecode_ = CreateVMInternalBytecode(
      KernelBytecode::kVMInternal_ImplicitStaticGetter);

  *implicit_static_setter_bytecode_ = CreateVMInternalBytecode(
      KernelBytecode::kVMInternal_ImplicitStaticSetter);

  *method_extractor_bytecode_ =
      CreateVMInternalBytecode(KernelBytecode::kVMInternal_MethodExtractor);

  *invoke_closure_bytecode_ =
      CreateVMInternalBytecode(KernelBytecode::kVMInternal_InvokeClosure);

  *invoke_field_bytecode_ =
      CreateVMInternalBytecode(KernelBytecode::kVMInternal_InvokeField);

  *nsm_dispatcher_bytecode_ = CreateVMInternalBytecode(
      KernelBytecode::kVMInternal_NoSuchMethodDispatcher);

  *dynamic_invocation_forwarder_bytecode_ = CreateVMInternalBytecode(
      KernelBytecode::kVMInternal_ForwardDynamicInvocation);

  *implicit_static_closure_bytecode_ = CreateVMInternalBytecode(
      KernelBytecode::kVMInternal_ImplicitStaticClosure);

  *implicit_instance_closure_bytecode_ = CreateVMInternalBytecode(
      KernelBytecode::kVMInternal_ImplicitInstanceClosure);

  *implicit_constructor_closure_bytecode_ = CreateVMInternalBytecode(
      KernelBytecode::kVMInternal_ImplicitConstructorClosure);
#endif  // defined(DART_DYNAMIC_MODULES)

  // Some thread fields need to be reinitialized as null constants have not been
  // initialized until now.
  thread->ClearStickyError();

  ASSERT(!null_object_->IsSmi());
  ASSERT(!null_class_->IsSmi());
  ASSERT(null_class_->IsClass());
  ASSERT(!null_array_->IsSmi());
  ASSERT(null_array_->IsArray());
  ASSERT(!null_string_->IsSmi());
  ASSERT(null_string_->IsString());
  ASSERT(!null_instance_->IsSmi());
  ASSERT(null_instance_->IsInstance());
  ASSERT(!null_function_->IsSmi());
  ASSERT(null_function_->IsFunction());
  ASSERT(!null_function_type_->IsSmi());
  ASSERT(null_function_type_->IsFunctionType());
  ASSERT(!null_record_type_->IsSmi());
  ASSERT(null_record_type_->IsRecordType());
  ASSERT(!null_type_arguments_->IsSmi());
  ASSERT(null_type_arguments_->IsTypeArguments());
  ASSERT(!null_compressed_stackmaps_->IsSmi());
  ASSERT(null_compressed_stackmaps_->IsCompressedStackMaps());
  ASSERT(!empty_array_->IsSmi());
  ASSERT(empty_array_->IsArray());
  ASSERT(!empty_instantiations_cache_array_->IsSmi());
  ASSERT(empty_instantiations_cache_array_->IsArray());
  ASSERT(!empty_subtype_test_cache_array_->IsSmi());
  ASSERT(empty_subtype_test_cache_array_->IsArray());
  ASSERT(!empty_type_arguments_->IsSmi());
  ASSERT(empty_type_arguments_->IsTypeArguments());
  ASSERT(!empty_context_scope_->IsSmi());
  ASSERT(empty_context_scope_->IsContextScope());
  ASSERT(!empty_compressed_stackmaps_->IsSmi());
  ASSERT(empty_compressed_stackmaps_->IsCompressedStackMaps());
  ASSERT(!empty_descriptors_->IsSmi());
  ASSERT(empty_descriptors_->IsPcDescriptors());
  ASSERT(!empty_var_descriptors_->IsSmi());
  ASSERT(empty_var_descriptors_->IsLocalVarDescriptors());
  ASSERT(!empty_exception_handlers_->IsSmi());
  ASSERT(empty_exception_handlers_->IsExceptionHandlers());
  ASSERT(!empty_async_exception_handlers_->IsSmi());
  ASSERT(empty_async_exception_handlers_->IsExceptionHandlers());
  ASSERT(!sentinel_->IsSmi());
  ASSERT(sentinel_->IsSentinel());
  ASSERT(!unknown_constant_->IsSmi());
  ASSERT(unknown_constant_->IsSentinel());
  ASSERT(!non_constant_->IsSmi());
  ASSERT(non_constant_->IsSentinel());
  ASSERT(!optimized_out_->IsSmi());
  ASSERT(optimized_out_->IsSentinel());
  ASSERT(!bool_true_->IsSmi());
  ASSERT(bool_true_->IsBool());
  ASSERT(!bool_false_->IsSmi());
  ASSERT(bool_false_->IsBool());
  ASSERT(smi_illegal_cid_->IsSmi());
  ASSERT(smi_zero_->IsSmi());
  ASSERT(!no_callbacks_error_->IsSmi());
  ASSERT(no_callbacks_error_->IsApiError());
  ASSERT(!unwind_in_progress_error_->IsSmi());
  ASSERT(unwind_in_progress_error_->IsUnwindError());
  ASSERT(!snapshot_writer_error_->IsSmi());
  ASSERT(snapshot_writer_error_->IsLanguageError());
  ASSERT(!branch_offset_error_->IsSmi());
  ASSERT(branch_offset_error_->IsLanguageError());
  ASSERT(!background_compilation_error_->IsSmi());
  ASSERT(background_compilation_error_->IsLanguageError());
  ASSERT(!out_of_memory_error_->IsSmi());
  ASSERT(out_of_memory_error_->IsLanguageError());
  ASSERT(!vm_isolate_snapshot_object_table_->IsSmi());
  ASSERT(vm_isolate_snapshot_object_table_->IsArray());
  ASSERT(!synthetic_getter_parameter_types_->IsSmi());
  ASSERT(synthetic_getter_parameter_types_->IsArray());
  ASSERT(!synthetic_getter_parameter_names_->IsSmi());
  ASSERT(synthetic_getter_parameter_names_->IsArray());
  ASSERT(!implicit_getter_bytecode_->IsSmi());
  ASSERT(implicit_getter_bytecode_->IsBytecode());
  ASSERT(!implicit_setter_bytecode_->IsSmi());
  ASSERT(implicit_setter_bytecode_->IsBytecode());
  ASSERT(!implicit_static_getter_bytecode_->IsSmi());
  ASSERT(implicit_static_getter_bytecode_->IsBytecode());
  ASSERT(!implicit_static_setter_bytecode_->IsSmi());
  ASSERT(implicit_static_setter_bytecode_->IsBytecode());
  ASSERT(!method_extractor_bytecode_->IsSmi());
  ASSERT(method_extractor_bytecode_->IsBytecode());
  ASSERT(!invoke_closure_bytecode_->IsSmi());
  ASSERT(invoke_closure_bytecode_->IsBytecode());
  ASSERT(!invoke_field_bytecode_->IsSmi());
  ASSERT(invoke_field_bytecode_->IsBytecode());
  ASSERT(!nsm_dispatcher_bytecode_->IsSmi());
  ASSERT(nsm_dispatcher_bytecode_->IsBytecode());
  ASSERT(!dynamic_invocation_forwarder_bytecode_->IsSmi());
  ASSERT(dynamic_invocation_forwarder_bytecode_->IsBytecode());
  ASSERT(!implicit_static_closure_bytecode_->IsSmi());
  ASSERT(implicit_static_closure_bytecode_->IsBytecode());
  ASSERT(!implicit_instance_closure_bytecode_->IsSmi());
  ASSERT(implicit_instance_closure_bytecode_->IsBytecode());
  ASSERT(!implicit_constructor_closure_bytecode_->IsSmi());
  ASSERT(implicit_constructor_closure_bytecode_->IsBytecode());
}

void Object::FinishInit(IsolateGroup* isolate_group) {
  // The type testing stubs we initialize in AbstractType objects for the
  // canonical type of kDynamicCid/kVoidCid need to be set in this
  // method, which is called after StubCode::InitOnce().
  Code& code = Code::Handle();

  code = TypeTestingStubGenerator::DefaultCodeForType(*dynamic_type_);
  dynamic_type_->InitializeTypeTestingStubNonAtomic(code);

  code = TypeTestingStubGenerator::DefaultCodeForType(*void_type_);
  void_type_->InitializeTypeTestingStubNonAtomic(code);
}

void Object::Cleanup() {
  null_ = static_cast<ObjectPtr>(RAW_NULL);
  true_ = static_cast<BoolPtr>(RAW_NULL);
  false_ = static_cast<BoolPtr>(RAW_NULL);
  class_class_ = static_cast<ClassPtr>(RAW_NULL);
  dynamic_class_ = static_cast<ClassPtr>(RAW_NULL);
  void_class_ = static_cast<ClassPtr>(RAW_NULL);
  type_parameters_class_ = static_cast<ClassPtr>(RAW_NULL);
  type_arguments_class_ = static_cast<ClassPtr>(RAW_NULL);
  patch_class_class_ = static_cast<ClassPtr>(RAW_NULL);
  function_class_ = static_cast<ClassPtr>(RAW_NULL);
  closure_data_class_ = static_cast<ClassPtr>(RAW_NULL);
  ffi_trampoline_data_class_ = static_cast<ClassPtr>(RAW_NULL);
  field_class_ = static_cast<ClassPtr>(RAW_NULL);
  script_class_ = static_cast<ClassPtr>(RAW_NULL);
  library_class_ = static_cast<ClassPtr>(RAW_NULL);
  namespace_class_ = static_cast<ClassPtr>(RAW_NULL);
  kernel_program_info_class_ = static_cast<ClassPtr>(RAW_NULL);
  code_class_ = static_cast<ClassPtr>(RAW_NULL);
  instructions_class_ = static_cast<ClassPtr>(RAW_NULL);
  instructions_section_class_ = static_cast<ClassPtr>(RAW_NULL);
  instructions_table_class_ = static_cast<ClassPtr>(RAW_NULL);
  object_pool_class_ = static_cast<ClassPtr>(RAW_NULL);
  pc_descriptors_class_ = static_cast<ClassPtr>(RAW_NULL);
  code_source_map_class_ = static_cast<ClassPtr>(RAW_NULL);
  compressed_stackmaps_class_ = static_cast<ClassPtr>(RAW_NULL);
  var_descriptors_class_ = static_cast<ClassPtr>(RAW_NULL);
  exception_handlers_class_ = static_cast<ClassPtr>(RAW_NULL);
  context_class_ = static_cast<ClassPtr>(RAW_NULL);
  context_scope_class_ = static_cast<ClassPtr>(RAW_NULL);
  bytecode_class_ = static_cast<ClassPtr>(RAW_NULL);
  singletargetcache_class_ = static_cast<ClassPtr>(RAW_NULL);
  unlinkedcall_class_ = static_cast<ClassPtr>(RAW_NULL);
  monomorphicsmiablecall_class_ = static_cast<ClassPtr>(RAW_NULL);
  icdata_class_ = static_cast<ClassPtr>(RAW_NULL);
  megamorphic_cache_class_ = static_cast<ClassPtr>(RAW_NULL);
  subtypetestcache_class_ = static_cast<ClassPtr>(RAW_NULL);
  loadingunit_class_ = static_cast<ClassPtr>(RAW_NULL);
  api_error_class_ = static_cast<ClassPtr>(RAW_NULL);
  language_error_class_ = static_cast<ClassPtr>(RAW_NULL);
  unhandled_exception_class_ = static_cast<ClassPtr>(RAW_NULL);
  unwind_error_class_ = static_cast<ClassPtr>(RAW_NULL);
}

// An object visitor which will mark all visited objects. This is used to
// premark all objects in the vm_isolate_ heap.  Also precalculates hash
// codes so that we can get the identity hash code of objects in the read-
// only VM isolate.
class FinalizeVMIsolateVisitor : public ObjectVisitor {
 public:
  FinalizeVMIsolateVisitor()
#if defined(HASH_IN_OBJECT_HEADER)
      : counter_(1337)
#endif
  {
  }

  void VisitObject(ObjectPtr obj) {
    // Free list elements should never be marked.
    ASSERT(!obj->untag()->IsMarked());
    // No forwarding corpses in the VM isolate.
    ASSERT(!obj->IsForwardingCorpse());
    if (!obj->IsFreeListElement()) {
      obj->untag()->SetMarkBitUnsynchronized();
      Object::FinalizeReadOnlyObject(obj);
#if defined(HASH_IN_OBJECT_HEADER)
      // These objects end up in the read-only VM isolate which is shared
      // between isolates, so we have to prepopulate them with identity hash
      // codes, since we can't add hash codes later.
      if (Object::GetCachedHash(obj) == 0) {
        // Some classes have identity hash codes that depend on their contents,
        // not per object.
        ASSERT(!obj->IsStringInstance());
        if (obj == Object::null()) {
          Object::SetCachedHashIfNotSet(obj, kNullIdentityHash);
        } else if (obj == Object::bool_true().ptr()) {
          Object::SetCachedHashIfNotSet(obj, kTrueIdentityHash);
        } else if (obj == Object::bool_false().ptr()) {
          Object::SetCachedHashIfNotSet(obj, kFalseIdentityHash);
        } else if (!obj->IsMint() && !obj->IsDouble()) {
          counter_ += 2011;  // The year Dart was announced and a prime.
          counter_ &= 0x3fffffff;
          if (counter_ == 0) counter_++;
          Object::SetCachedHashIfNotSet(obj, counter_);
        }
      }
#endif
#if !defined(DART_PRECOMPILED_RUNTIME)
      if (obj->IsClass()) {
        // Won't be able to update read-only VM isolate classes if implementors
        // are discovered later. We use kVoidCid instead of kDynamicCid here to
        // be able to distinguish read-only VM isolate classes during reload.
        // See ProgramReloadContext::RestoreClassHierarchyInvariants.
        static_cast<ClassPtr>(obj)->untag()->implementor_cid_ = kVoidCid;
      }
#endif
    }
  }

 private:
#if defined(HASH_IN_OBJECT_HEADER)
  int32_t counter_;
#endif
};

#define SET_CLASS_NAME(class_name, name)                                       \
  cls = class_name##_class();                                                  \
  cls.set_name(Symbols::name());

void Object::FinalizeVMIsolate(IsolateGroup* isolate_group) {
  // Should only be run by the vm isolate.
  ASSERT(isolate_group == Dart::vm_isolate_group());

  // Finish initialization of synthetic_getter_parameter_names_ which was
  // Started in Object::InitOnce()
  synthetic_getter_parameter_names_->SetAt(0, Symbols::This());

  // Set up names for all VM singleton classes.
  Class& cls = Class::Handle();

  SET_CLASS_NAME(class, Class);
  SET_CLASS_NAME(dynamic, Dynamic);
  SET_CLASS_NAME(void, Void);
  SET_CLASS_NAME(type_parameters, TypeParameters);
  SET_CLASS_NAME(type_arguments, TypeArguments);
  SET_CLASS_NAME(patch_class, PatchClass);
  SET_CLASS_NAME(function, Function);
  SET_CLASS_NAME(closure_data, ClosureData);
  SET_CLASS_NAME(ffi_trampoline_data, FfiTrampolineData);
  SET_CLASS_NAME(field, Field);
  SET_CLASS_NAME(script, Script);
  SET_CLASS_NAME(library, LibraryClass);
  SET_CLASS_NAME(namespace, Namespace);
  SET_CLASS_NAME(kernel_program_info, KernelProgramInfo);
  SET_CLASS_NAME(weak_serialization_reference, WeakSerializationReference);
  SET_CLASS_NAME(weak_array, WeakArray);
  SET_CLASS_NAME(code, Code);
  SET_CLASS_NAME(instructions, Instructions);
  SET_CLASS_NAME(instructions_section, InstructionsSection);
  SET_CLASS_NAME(instructions_table, InstructionsTable);
  SET_CLASS_NAME(object_pool, ObjectPool);
  SET_CLASS_NAME(code_source_map, CodeSourceMap);
  SET_CLASS_NAME(pc_descriptors, PcDescriptors);
  SET_CLASS_NAME(compressed_stackmaps, CompressedStackMaps);
  SET_CLASS_NAME(var_descriptors, LocalVarDescriptors);
  SET_CLASS_NAME(exception_handlers, ExceptionHandlers);
  SET_CLASS_NAME(context, Context);
  SET_CLASS_NAME(context_scope, ContextScope);
  SET_CLASS_NAME(bytecode, Bytecode);
  SET_CLASS_NAME(sentinel, Sentinel);
  SET_CLASS_NAME(singletargetcache, SingleTargetCache);
  SET_CLASS_NAME(unlinkedcall, UnlinkedCall);
  SET_CLASS_NAME(monomorphicsmiablecall, MonomorphicSmiableCall);
  SET_CLASS_NAME(icdata, ICData);
  SET_CLASS_NAME(megamorphic_cache, MegamorphicCache);
  SET_CLASS_NAME(subtypetestcache, SubtypeTestCache);
  SET_CLASS_NAME(loadingunit, LoadingUnit);
  SET_CLASS_NAME(api_error, ApiError);
  SET_CLASS_NAME(language_error, LanguageError);
  SET_CLASS_NAME(unhandled_exception, UnhandledException);
  SET_CLASS_NAME(unwind_error, UnwindError);

  // Set up names for classes which are also pre-allocated in the vm isolate.
  cls = isolate_group->object_store()->array_class();
  cls.set_name(Symbols::_List());
  cls = isolate_group->object_store()->one_byte_string_class();
  cls.set_name(Symbols::OneByteString());
  cls = isolate_group->object_store()->never_class();
  cls.set_name(Symbols::Never());

  // Set up names for the pseudo-classes for free list elements and forwarding
  // corpses. Mainly this makes VM debugging easier.
  cls = isolate_group->class_table()->At(kFreeListElement);
  cls.set_name(Symbols::FreeListElement());
  cls = isolate_group->class_table()->At(kForwardingCorpse);
  cls.set_name(Symbols::ForwardingCorpse());

#if defined(DART_PRECOMPILER)
  const auto& function =
      Function::Handle(StubCode::UnknownDartCode().function());
  function.set_name(Symbols::OptimizedOut());
#endif  // defined(DART_PRECOMPILER)

  {
    ASSERT(isolate_group == Dart::vm_isolate_group());
    Thread* thread = Thread::Current();
    WritableVMIsolateScope scope(thread);
    HeapIterationScope iteration(thread);
    FinalizeVMIsolateVisitor premarker;
    ASSERT(isolate_group->heap()->UsedInWords(Heap::kNew) == 0);
    iteration.IterateOldObjectsNoImagePages(&premarker);
    // Make the VM isolate read-only again after setting all objects as marked.
    // Note objects in image pages are already pre-marked.
  }
}

void Object::FinalizeReadOnlyObject(ObjectPtr object) {
  NoSafepointScope no_safepoint;
  intptr_t cid = object->GetClassIdOfHeapObject();
  if (cid == kOneByteStringCid) {
    OneByteStringPtr str = static_cast<OneByteStringPtr>(object);
    if (String::GetCachedHash(str) == 0) {
      intptr_t hash = String::Hash(str);
      String::SetCachedHashIfNotSet(str, hash);
    }
    intptr_t size = OneByteString::UnroundedSize(str);
    ASSERT(size <= str->untag()->HeapSize());
    memset(reinterpret_cast<void*>(UntaggedObject::ToAddr(str) + size), 0,
           str->untag()->HeapSize() - size);
  } else if (cid == kTwoByteStringCid) {
    TwoByteStringPtr str = static_cast<TwoByteStringPtr>(object);
    if (String::GetCachedHash(str) == 0) {
      intptr_t hash = String::Hash(str);
      String::SetCachedHashIfNotSet(str, hash);
    }
    ASSERT(String::GetCachedHash(str) != 0);
    intptr_t size = TwoByteString::UnroundedSize(str);
    ASSERT(size <= str->untag()->HeapSize());
    memset(reinterpret_cast<void*>(UntaggedObject::ToAddr(str) + size), 0,
           str->untag()->HeapSize() - size);
  } else if (cid == kCodeSourceMapCid) {
    CodeSourceMapPtr map = CodeSourceMap::RawCast(object);
    intptr_t size = CodeSourceMap::UnroundedSize(map);
    ASSERT(size <= map->untag()->HeapSize());
    memset(reinterpret_cast<void*>(UntaggedObject::ToAddr(map) + size), 0,
           map->untag()->HeapSize() - size);
  } else if (cid == kCompressedStackMapsCid) {
    CompressedStackMapsPtr maps = CompressedStackMaps::RawCast(object);
    intptr_t size = CompressedStackMaps::UnroundedSize(maps);
    ASSERT(size <= maps->untag()->HeapSize());
    memset(reinterpret_cast<void*>(UntaggedObject::ToAddr(maps) + size), 0,
           maps->untag()->HeapSize() - size);
  } else if (cid == kPcDescriptorsCid) {
    PcDescriptorsPtr desc = PcDescriptors::RawCast(object);
    intptr_t size = PcDescriptors::UnroundedSize(desc);
    ASSERT(size <= desc->untag()->HeapSize());
    memset(reinterpret_cast<void*>(UntaggedObject::ToAddr(desc) + size), 0,
           desc->untag()->HeapSize() - size);
  }
}

void Object::set_vm_isolate_snapshot_object_table(const Array& table) {
  ASSERT(Isolate::Current() == Dart::vm_isolate());
  *vm_isolate_snapshot_object_table_ = table.ptr();
}

// Make unused space in an object whose type has been transformed safe
// for traversing during GC.
// The unused part of the transformed object is marked as a FreeListElement
// object that is not inserted into to the freelist.
void Object::MakeUnusedSpaceTraversable(const Object& obj,
                                        intptr_t original_size,
                                        intptr_t used_size) {
  ASSERT(Thread::Current()->no_safepoint_scope_depth() > 0);
  ASSERT(!obj.IsNull());
  ASSERT(original_size >= used_size);
  if (original_size > used_size) {
    intptr_t leftover_size = original_size - used_size;
    uword addr = UntaggedObject::ToAddr(obj.ptr()) + used_size;
    if (obj.ptr()->IsNewObject()) {
      FreeListElement::AsElementNew(addr, leftover_size);
    } else {
      FreeListElement::AsElement(addr, leftover_size);
    }
    // On architectures with a relaxed memory model, the concurrent marker may
    // observe the write of the filler object's header before observing the
    // new array length, and so treat it as a pointer. Ensure it is a Smi so
    // the marker won't dereference it.
    ASSERT((*reinterpret_cast<uword*>(addr) & kSmiTagMask) == kSmiTag);
    ASSERT((*reinterpret_cast<uword*>(addr + kWordSize) & kSmiTagMask) ==
           kSmiTag);
  }
}

void Object::VerifyBuiltinVtables() {
#if defined(DEBUG)
  ASSERT(builtin_vtables_[kIllegalCid] == 0);
  ASSERT(builtin_vtables_[kFreeListElement] == 0);
  ASSERT(builtin_vtables_[kForwardingCorpse] == 0);
  ClassTable* table = IsolateGroup::Current()->class_table();
  for (intptr_t cid = kObjectCid; cid < kNumPredefinedCids; cid++) {
    if (table->HasValidClassAt(cid)) {
      ASSERT(builtin_vtables_[cid] != 0);
    }
  }
#endif
}

void Object::RegisterClass(const Class& cls,
                           const String& name,
                           const Library& lib) {
  ASSERT(name.Length() > 0);
  ASSERT(name.CharAt(0) != '_');
  cls.set_name(name);
  lib.AddClass(cls);
}

void Object::RegisterPrivateClass(const Class& cls,
                                  const String& public_class_name,
                                  const Library& lib) {
  ASSERT(public_class_name.Length() > 0);
  ASSERT(public_class_name.CharAt(0) == '_');
  String& str = String::Handle();
  str = lib.PrivateName(public_class_name);
  cls.set_name(str);
  lib.AddClass(cls);
}

// Initialize a new isolate from source or from a snapshot.
//
// There are three possibilities:
//   1. Running a Kernel binary.  This function will bootstrap from the KERNEL
//      file.
//   2. There is no vm snapshot.  This function will bootstrap from source.
//   3. There is a vm snapshot.  The caller should initialize from the snapshot.
//
// A non-null kernel argument indicates (1).
// A nullptr kernel indicates (2) or (3).
ErrorPtr Object::Init(IsolateGroup* isolate_group,
                      const uint8_t* kernel_buffer,
                      intptr_t kernel_buffer_size) {
  Thread* thread = Thread::Current();
  Zone* zone = thread->zone();
  ASSERT(isolate_group == thread->isolate_group());
  TIMELINE_DURATION(thread, Isolate, "Object::Init");

#if defined(DART_PRECOMPILED_RUNTIME)
  const bool bootstrapping = false;
#else
  const bool is_kernel = (kernel_buffer != nullptr);
  const bool bootstrapping =
      (Dart::vm_snapshot_kind() == Snapshot::kNone) || is_kernel;
#endif  // defined(DART_PRECOMPILED_RUNTIME).

  if (bootstrapping) {
#if !defined(DART_PRECOMPILED_RUNTIME)
    // Object::Init version when we are bootstrapping from source or from a
    // Kernel binary.
    // This will initialize isolate group object_store, shared by all isolates
    // running in the isolate group.
    ObjectStore* object_store = isolate_group->object_store();
    SafepointWriteRwLocker ml(thread, isolate_group->program_lock());

    Class& cls = Class::Handle(zone);
    Type& type = Type::Handle(zone);
    Array& array = Array::Handle(zone);
    WeakArray& weak_array = WeakArray::Handle(zone);
    Library& lib = Library::Handle(zone);
    TypeArguments& type_args = TypeArguments::Handle(zone);

    // All RawArray fields will be initialized to an empty array, therefore
    // initialize array class first.
    cls = Class::New<Array, RTN::Array>(isolate_group);
    ASSERT(object_store->array_class() == Class::null());
    object_store->set_array_class(cls);

    // VM classes that are parameterized (Array, ImmutableArray,
    // GrowableObjectArray, Map, ConstMap,
    // Set, ConstSet) are also pre-finalized, so
    // CalculateFieldOffsets() is not called, so we need to set the offset
    // of their type_arguments_ field, which is explicitly
    // declared in their respective Raw* classes.
    cls.set_type_arguments_field_offset(Array::type_arguments_offset(),
                                        RTN::Array::type_arguments_offset());
    cls.set_num_type_arguments_unsafe(1);

    // Set up the growable object array class (Has to be done after the array
    // class is setup as one of its field is an array object).
    cls = Class::New<GrowableObjectArray, RTN::GrowableObjectArray>(
        isolate_group);
    object_store->set_growable_object_array_class(cls);
    cls.set_type_arguments_field_offset(
        GrowableObjectArray::type_arguments_offset(),
        RTN::GrowableObjectArray::type_arguments_offset());
    cls.set_num_type_arguments_unsafe(1);

    // Initialize hash set for regexp_table_.
    const intptr_t kInitialCanonicalRegExpSize = 4;
    weak_array = HashTables::New<CanonicalRegExpSet>(
        kInitialCanonicalRegExpSize, Heap::kOld);
    object_store->set_regexp_table(weak_array);

    // Initialize hash set for canonical types.
    const intptr_t kInitialCanonicalTypeSize = 16;
    array = HashTables::New<CanonicalTypeSet>(kInitialCanonicalTypeSize,
                                              Heap::kOld);
    object_store->set_canonical_types(array);

    // Initialize hash set for canonical function types.
    const intptr_t kInitialCanonicalFunctionTypeSize = 16;
    array = HashTables::New<CanonicalFunctionTypeSet>(
        kInitialCanonicalFunctionTypeSize, Heap::kOld);
    object_store->set_canonical_function_types(array);

    // Initialize hash set for canonical record types.
    const intptr_t kInitialCanonicalRecordTypeSize = 16;
    array = HashTables::New<CanonicalRecordTypeSet>(
        kInitialCanonicalRecordTypeSize, Heap::kOld);
    object_store->set_canonical_record_types(array);

    // Initialize hash set for canonical type parameters.
    const intptr_t kInitialCanonicalTypeParameterSize = 4;
    array = HashTables::New<CanonicalTypeParameterSet>(
        kInitialCanonicalTypeParameterSize, Heap::kOld);
    object_store->set_canonical_type_parameters(array);

    // Initialize hash set for canonical_type_arguments_.
    const intptr_t kInitialCanonicalTypeArgumentsSize = 4;
    array = HashTables::New<CanonicalTypeArgumentsSet>(
        kInitialCanonicalTypeArgumentsSize, Heap::kOld);
    object_store->set_canonical_type_arguments(array);

    // Setup type class early in the process.
    const Class& type_cls =
        Class::Handle(zone, Class::New<Type, RTN::Type>(isolate_group));
    const Class& function_type_cls = Class::Handle(
        zone, Class::New<FunctionType, RTN::FunctionType>(isolate_group));
    const Class& record_type_cls = Class::Handle(
        zone, Class::New<RecordType, RTN::RecordType>(isolate_group));
    const Class& type_parameter_cls = Class::Handle(
        zone, Class::New<TypeParameter, RTN::TypeParameter>(isolate_group));
    const Class& library_prefix_cls = Class::Handle(
        zone, Class::New<LibraryPrefix, RTN::LibraryPrefix>(isolate_group));

    // Pre-allocate the OneByteString class needed by the symbol table.
    cls = Class::NewStringClass(kOneByteStringCid, isolate_group);
    object_store->set_one_byte_string_class(cls);

    // Pre-allocate the TwoByteString class needed by the symbol table.
    cls = Class::NewStringClass(kTwoByteStringCid, isolate_group);
    object_store->set_two_byte_string_class(cls);

    // Setup the symbol table for the symbols created in the isolate.
    Symbols::SetupSymbolTable(isolate_group);

    // Set up the libraries array before initializing the core library.
    const GrowableObjectArray& libraries =
        GrowableObjectArray::Handle(zone, GrowableObjectArray::New(Heap::kOld));
    object_store->set_libraries(libraries);

    // Pre-register the core library.
    Library::InitCoreLibrary(isolate_group);

    // Basic infrastructure has been setup, initialize the class dictionary.
    const Library& core_lib = Library::Handle(zone, Library::CoreLibrary());
    ASSERT(!core_lib.IsNull());

    const GrowableObjectArray& pending_classes =
        GrowableObjectArray::Handle(zone, GrowableObjectArray::New());
    object_store->set_pending_classes(pending_classes);

    // Now that the symbol table is initialized and that the core dictionary as
    // well as the core implementation dictionary have been setup, preallocate
    // remaining classes and register them by name in the dictionaries.
    String& name = String::Handle(zone);
    cls = object_store->array_class();  // Was allocated above.
    RegisterPrivateClass(cls, Symbols::_List(), core_lib);
    pending_classes.Add(cls);
    // We cannot use NewNonParameterizedType(), because Array is
    // parameterized.  Warning: class _List has not been patched yet. Its
    // declared number of type parameters is still 0. It will become 1 after
    // patching. The array type allocated below represents the raw type _List
    // and not _List<E> as we could expect. Use with caution.
    type = Type::New(Class::Handle(zone, cls.ptr()),
                     Object::null_type_arguments(), Nullability::kNonNullable);
    type.SetIsFinalized();
    type ^= type.Canonicalize(thread);
    object_store->set_array_type(type);

    cls = object_store->growable_object_array_class();  // Was allocated above.
    RegisterPrivateClass(cls, Symbols::_GrowableList(), core_lib);
    pending_classes.Add(cls);

    cls = Class::New<Array, RTN::Array>(kImmutableArrayCid, isolate_group);
    object_store->set_immutable_array_class(cls);
    cls.set_type_arguments_field_offset(Array::type_arguments_offset(),
                                        RTN::Array::type_arguments_offset());
    cls.set_num_type_arguments_unsafe(1);
    ASSERT(object_store->immutable_array_class() !=
           object_store->array_class());
    cls.set_is_prefinalized();
    RegisterPrivateClass(cls, Symbols::_ImmutableList(), core_lib);
    pending_classes.Add(cls);

    cls = object_store->one_byte_string_class();  // Was allocated above.
    RegisterPrivateClass(cls, Symbols::OneByteString(), core_lib);
    pending_classes.Add(cls);

    cls = object_store->two_byte_string_class();  // Was allocated above.
    RegisterPrivateClass(cls, Symbols::TwoByteString(), core_lib);
    pending_classes.Add(cls);

    // Pre-register the isolate library so the native class implementations can
    // be hooked up before compiling it.
    Library& isolate_lib = Library::Handle(
        zone, Library::LookupLibrary(thread, Symbols::DartIsolate()));
    if (isolate_lib.IsNull()) {
      isolate_lib = Library::NewLibraryHelper(Symbols::DartIsolate(), true);
      isolate_lib.SetLoadRequested();
      isolate_lib.Register(thread);
    }
    object_store->set_bootstrap_library(ObjectStore::kIsolate, isolate_lib);
    ASSERT(!isolate_lib.IsNull());
    ASSERT(isolate_lib.ptr() == Library::IsolateLibrary());

    cls = Class::New<Capability, RTN::Capability>(isolate_group);
    RegisterPrivateClass(cls, Symbols::_Capability(), isolate_lib);
    pending_classes.Add(cls);

    cls = Class::New<ReceivePort, RTN::ReceivePort>(isolate_group);
    RegisterPrivateClass(cls, Symbols::_RawReceivePort(), isolate_lib);
    pending_classes.Add(cls);

    cls = Class::New<SendPort, RTN::SendPort>(isolate_group);
    RegisterPrivateClass(cls, Symbols::_SendPort(), isolate_lib);
    pending_classes.Add(cls);

    cls = Class::New<TransferableTypedData, RTN::TransferableTypedData>(
        isolate_group);
    RegisterPrivateClass(cls, Symbols::_TransferableTypedDataImpl(),
                         isolate_lib);
    pending_classes.Add(cls);

    const Class& stacktrace_cls = Class::Handle(
        zone, Class::New<StackTrace, RTN::StackTrace>(isolate_group));
    RegisterPrivateClass(stacktrace_cls, Symbols::_StackTrace(), core_lib);
    pending_classes.Add(stacktrace_cls);
    // Super type set below, after Object is allocated.

    cls = Class::New<RegExp, RTN::RegExp>(isolate_group);
    RegisterPrivateClass(cls, Symbols::_RegExp(), core_lib);
    pending_classes.Add(cls);

    // Initialize the base interfaces used by the core VM classes.

    // Allocate and initialize the pre-allocated classes in the core library.
    // The script and token index of these pre-allocated classes is set up when
    // the corelib script is compiled.
    cls = Class::New<Instance, RTN::Instance>(kInstanceCid, isolate_group);
    object_store->set_object_class(cls);
    cls.set_name(Symbols::Object());
    cls.set_num_type_arguments_unsafe(0);
    cls.set_is_prefinalized();
    cls.set_is_const();
    core_lib.AddClass(cls);
    pending_classes.Add(cls);
    type = Type::NewNonParameterizedType(cls);
    ASSERT(type.IsCanonical());
    object_store->set_object_type(type);
    type = type.ToNullability(Nullability::kNonNullable, Heap::kOld);
    ASSERT(type.IsCanonical());
    object_store->set_non_nullable_object_type(type);
    type = type.ToNullability(Nullability::kNullable, Heap::kOld);
    ASSERT(type.IsCanonical());
    object_store->set_nullable_object_type(type);

    cls = Class::New<Bool, RTN::Bool>(isolate_group);
    object_store->set_bool_class(cls);
    RegisterClass(cls, Symbols::Bool(), core_lib);
    pending_classes.Add(cls);

    cls = Class::New<Instance, RTN::Instance>(kNullCid, isolate_group);
    object_store->set_null_class(cls);
    cls.set_num_type_arguments_unsafe(0);
    cls.set_is_prefinalized();
    RegisterClass(cls, Symbols::Null(), core_lib);
    pending_classes.Add(cls);

    cls = Class::New<Instance, RTN::Instance>(kNeverCid, isolate_group);
    cls.set_num_type_arguments_unsafe(0);
    cls.set_is_allocate_finalized();
    cls.set_is_declaration_loaded();
    cls.set_is_type_finalized();
    cls.set_name(Symbols::Never());
    object_store->set_never_class(cls);

    ASSERT(!library_prefix_cls.IsNull());
    RegisterPrivateClass(library_prefix_cls, Symbols::_LibraryPrefix(),
                         core_lib);
    pending_classes.Add(library_prefix_cls);

    RegisterPrivateClass(type_cls, Symbols::_Type(), core_lib);
    pending_classes.Add(type_cls);

    RegisterPrivateClass(function_type_cls, Symbols::_FunctionType(), core_lib);
    pending_classes.Add(function_type_cls);

    RegisterPrivateClass(record_type_cls, Symbols::_RecordType(), core_lib);
    pending_classes.Add(record_type_cls);

    RegisterPrivateClass(type_parameter_cls, Symbols::_TypeParameter(),
                         core_lib);
    pending_classes.Add(type_parameter_cls);

    cls = Class::New<Integer, RTN::Integer>(isolate_group);
    object_store->set_integer_implementation_class(cls);
    RegisterPrivateClass(cls, Symbols::_IntegerImplementation(), core_lib);
    pending_classes.Add(cls);

    cls = Class::New<Smi, RTN::Smi>(isolate_group);
    object_store->set_smi_class(cls);
    RegisterPrivateClass(cls, Symbols::_Smi(), core_lib);
    pending_classes.Add(cls);

    cls = Class::New<Mint, RTN::Mint>(isolate_group);
    object_store->set_mint_class(cls);
    RegisterPrivateClass(cls, Symbols::_Mint(), core_lib);
    pending_classes.Add(cls);

    cls = Class::New<Double, RTN::Double>(isolate_group);
    object_store->set_double_class(cls);
    RegisterPrivateClass(cls, Symbols::_Double(), core_lib);
    pending_classes.Add(cls);

    // Class that represents the Dart class _Closure and C++ class Closure.
    cls = Class::New<Closure, RTN::Closure>(isolate_group);
    object_store->set_closure_class(cls);
    RegisterPrivateClass(cls, Symbols::_Closure(), core_lib);
    pending_classes.Add(cls);

    cls = Class::New<Record, RTN::Record>(isolate_group);
    RegisterPrivateClass(cls, Symbols::_Record(), core_lib);
    pending_classes.Add(cls);

    cls = Class::New<WeakProperty, RTN::WeakProperty>(isolate_group);
    object_store->set_weak_property_class(cls);
    RegisterPrivateClass(cls, Symbols::_WeakProperty(), core_lib);

    cls = Class::New<WeakReference, RTN::WeakReference>(isolate_group);
    cls.set_type_arguments_field_offset(
        WeakReference::type_arguments_offset(),
        RTN::WeakReference::type_arguments_offset());
    cls.set_num_type_arguments_unsafe(1);
    object_store->set_weak_reference_class(cls);
    RegisterPrivateClass(cls, Symbols::_WeakReference(), core_lib);

    // Pre-register the mirrors library so we can place the vm class
    // MirrorReference there rather than the core library.
    lib = Library::LookupLibrary(thread, Symbols::DartMirrors());
    if (lib.IsNull()) {
      lib = Library::NewLibraryHelper(Symbols::DartMirrors(), true);
      lib.SetLoadRequested();
      lib.Register(thread);
    }
    object_store->set_bootstrap_library(ObjectStore::kMirrors, lib);
    ASSERT(!lib.IsNull());
    ASSERT(lib.ptr() == Library::MirrorsLibrary());

    cls = Class::New<MirrorReference, RTN::MirrorReference>(isolate_group);
    RegisterPrivateClass(cls, Symbols::_MirrorReference(), lib);

    // Pre-register dart:_compact_hash library so that we could place
    // collection classes (_Map, _ConstMap, _Set, _ConstSet) here.
    lib = Library::LookupLibrary(thread, Symbols::DartCompactHash());
    if (lib.IsNull()) {
      lib = Library::NewLibraryHelper(Symbols::DartCompactHash(), true);
      lib.SetLoadRequested();
      lib.Register(thread);
    }
    object_store->set_bootstrap_library(ObjectStore::kCompactHash, lib);

    ASSERT(!lib.IsNull());
    ASSERT(lib.ptr() == Library::CompactHashLibrary());
    cls = Class::New<Map, RTN::Map>(isolate_group);
    object_store->set_map_impl_class(cls);
    cls.set_type_arguments_field_offset(Map::type_arguments_offset(),
                                        RTN::Map::type_arguments_offset());
    cls.set_num_type_arguments_unsafe(2);
    RegisterPrivateClass(cls, Symbols::_Map(), lib);
    pending_classes.Add(cls);

    cls = Class::New<Map, RTN::Map>(kConstMapCid, isolate_group);
    object_store->set_const_map_impl_class(cls);
    cls.set_type_arguments_field_offset(Map::type_arguments_offset(),
                                        RTN::Map::type_arguments_offset());
    cls.set_num_type_arguments_unsafe(2);
    cls.set_is_prefinalized();
    RegisterPrivateClass(cls, Symbols::_ConstMap(), lib);
    pending_classes.Add(cls);

    cls = Class::New<Set, RTN::Set>(isolate_group);
    object_store->set_set_impl_class(cls);
    cls.set_type_arguments_field_offset(Set::type_arguments_offset(),
                                        RTN::Set::type_arguments_offset());
    cls.set_num_type_arguments_unsafe(1);
    RegisterPrivateClass(cls, Symbols::_Set(), lib);
    pending_classes.Add(cls);

    cls = Class::New<Set, RTN::Set>(kConstSetCid, isolate_group);
    object_store->set_const_set_impl_class(cls);
    cls.set_type_arguments_field_offset(Set::type_arguments_offset(),
                                        RTN::Set::type_arguments_offset());
    cls.set_num_type_arguments_unsafe(1);
    cls.set_is_prefinalized();
    RegisterPrivateClass(cls, Symbols::_ConstSet(), lib);
    pending_classes.Add(cls);

    // Pre-register the collection library.
    lib = Library::LookupLibrary(thread, Symbols::DartCollection());
    if (lib.IsNull()) {
      lib = Library::NewLibraryHelper(Symbols::DartCollection(), true);
      lib.SetLoadRequested();
      lib.Register(thread);
    }
    object_store->set_bootstrap_library(ObjectStore::kCollection, lib);

    // Pre-register the async library so we can place the vm class
    // FutureOr there rather than the core library.
    lib = Library::LookupLibrary(thread, Symbols::DartAsync());
    if (lib.IsNull()) {
      lib = Library::NewLibraryHelper(Symbols::DartAsync(), true);
      lib.SetLoadRequested();
      lib.Register(thread);
    }
    object_store->set_bootstrap_library(ObjectStore::kAsync, lib);
    ASSERT(!lib.IsNull());
    ASSERT(lib.ptr() == Library::AsyncLibrary());
    cls = Class::New<FutureOr, RTN::FutureOr>(isolate_group);
    cls.set_type_arguments_field_offset(FutureOr::type_arguments_offset(),
                                        RTN::FutureOr::type_arguments_offset());
    cls.set_num_type_arguments_unsafe(1);
    RegisterClass(cls, Symbols::FutureOr(), lib);
    pending_classes.Add(cls);
    object_store->set_future_or_class(cls);

    cls = Class::New<SuspendState, RTN::SuspendState>(isolate_group);
    RegisterPrivateClass(cls, Symbols::_SuspendState(), lib);
    pending_classes.Add(cls);

    // Pre-register the developer library so we can place the vm class
    // UserTag there rather than the core library.
    lib = Library::LookupLibrary(thread, Symbols::DartDeveloper());
    if (lib.IsNull()) {
      lib = Library::NewLibraryHelper(Symbols::DartDeveloper(), true);
      lib.SetLoadRequested();
      lib.Register(thread);
    }
    object_store->set_bootstrap_library(ObjectStore::kDeveloper, lib);
    ASSERT(!lib.IsNull());
    ASSERT(lib.ptr() == Library::DeveloperLibrary());
    cls = Class::New<UserTag, RTN::UserTag>(isolate_group);
    RegisterPrivateClass(cls, Symbols::_UserTag(), lib);
    pending_classes.Add(cls);

    // Setup some default native field classes which can be extended for
    // specifying native fields in dart classes.
    Library::InitNativeWrappersLibrary(isolate_group, is_kernel);
    ASSERT(object_store->native_wrappers_library() != Library::null());

    // Pre-register the typed_data library so the native class implementations
    // can be hooked up before compiling it.
    lib = Library::LookupLibrary(thread, Symbols::DartTypedData());
    if (lib.IsNull()) {
      lib = Library::NewLibraryHelper(Symbols::DartTypedData(), true);
      lib.SetLoadRequested();
      lib.Register(thread);
    }
    object_store->set_bootstrap_library(ObjectStore::kTypedData, lib);
    ASSERT(!lib.IsNull());
    ASSERT(lib.ptr() == Library::TypedDataLibrary());
#define REGISTER_TYPED_DATA_CLASS(clazz)                                       \
  cls = Class::NewTypedDataClass(kTypedData##clazz##ArrayCid, isolate_group);  \
  RegisterPrivateClass(cls, Symbols::_##clazz##List(), lib);

    DART_CLASS_LIST_TYPED_DATA(REGISTER_TYPED_DATA_CLASS);
#undef REGISTER_TYPED_DATA_CLASS
#define REGISTER_TYPED_DATA_VIEW_CLASS(clazz)                                  \
  cls =                                                                        \
      Class::NewTypedDataViewClass(kTypedData##clazz##ViewCid, isolate_group); \
  RegisterPrivateClass(cls, Symbols::_##clazz##View(), lib);                   \
  pending_classes.Add(cls);                                                    \
  cls = Class::NewUnmodifiableTypedDataViewClass(                              \
      kUnmodifiableTypedData##clazz##ViewCid, isolate_group);                  \
  RegisterPrivateClass(cls, Symbols::_Unmodifiable##clazz##View(), lib);       \
  pending_classes.Add(cls);

    CLASS_LIST_TYPED_DATA(REGISTER_TYPED_DATA_VIEW_CLASS);

    cls = Class::NewTypedDataViewClass(kByteDataViewCid, isolate_group);
    RegisterPrivateClass(cls, Symbols::_ByteDataView(), lib);
    pending_classes.Add(cls);
    cls = Class::NewUnmodifiableTypedDataViewClass(kUnmodifiableByteDataViewCid,
                                                   isolate_group);
    RegisterPrivateClass(cls, Symbols::_UnmodifiableByteDataView(), lib);
    pending_classes.Add(cls);

#undef REGISTER_TYPED_DATA_VIEW_CLASS
#define REGISTER_EXT_TYPED_DATA_CLASS(clazz)                                   \
  cls = Class::NewExternalTypedDataClass(kExternalTypedData##clazz##Cid,       \
                                         isolate_group);                       \
  RegisterPrivateClass(cls, Symbols::_External##clazz(), lib);

    cls = Class::New<Instance, RTN::Instance>(kByteBufferCid, isolate_group,
                                              /*register_class=*/false);
    cls.set_instance_size(0, 0);
    cls.set_next_field_offset(-kWordSize, -compiler::target::kWordSize);
    isolate_group->class_table()->Register(cls);
    RegisterPrivateClass(cls, Symbols::_ByteBuffer(), lib);
    pending_classes.Add(cls);

    CLASS_LIST_TYPED_DATA(REGISTER_EXT_TYPED_DATA_CLASS);
#undef REGISTER_EXT_TYPED_DATA_CLASS
    // Register Float32x4, Int32x4, and Float64x2 in the object store.
    cls = Class::New<Float32x4, RTN::Float32x4>(isolate_group);
    RegisterPrivateClass(cls, Symbols::_Float32x4(), lib);
    pending_classes.Add(cls);
    object_store->set_float32x4_class(cls);

    cls = Class::New<Instance, RTN::Instance>(kIllegalCid, isolate_group,
                                              /*register_class=*/true,
                                              /*is_abstract=*/true);
    RegisterClass(cls, Symbols::Float32x4(), lib);
    cls.set_num_type_arguments_unsafe(0);
    cls.set_is_prefinalized();
    type = Type::NewNonParameterizedType(cls);
    object_store->set_float32x4_type(type);

    cls = Class::New<Int32x4, RTN::Int32x4>(isolate_group);
    RegisterPrivateClass(cls, Symbols::_Int32x4(), lib);
    pending_classes.Add(cls);
    object_store->set_int32x4_class(cls);

    cls = Class::New<Instance, RTN::Instance>(kIllegalCid, isolate_group,
                                              /*register_class=*/true,
                                              /*is_abstract=*/true);
    RegisterClass(cls, Symbols::Int32x4(), lib);
    cls.set_num_type_arguments_unsafe(0);
    cls.set_is_prefinalized();
    type = Type::NewNonParameterizedType(cls);
    object_store->set_int32x4_type(type);

    cls = Class::New<Float64x2, RTN::Float64x2>(isolate_group);
    RegisterPrivateClass(cls, Symbols::_Float64x2(), lib);
    pending_classes.Add(cls);
    object_store->set_float64x2_class(cls);

    cls = Class::New<Instance, RTN::Instance>(kIllegalCid, isolate_group,
                                              /*register_class=*/true,
                                              /*is_abstract=*/true);
    RegisterClass(cls, Symbols::Float64x2(), lib);
    cls.set_num_type_arguments_unsafe(0);
    cls.set_is_prefinalized();
    type = Type::NewNonParameterizedType(cls);
    object_store->set_float64x2_type(type);

    // Set the super type of class StackTrace to Object type so that the
    // 'toString' method is implemented.
    type = object_store->object_type();
    stacktrace_cls.set_super_type(type);

    // Abstract class that represents the Dart class Type.
    // Note that this class is implemented by Dart class _AbstractType.
    cls = Class::New<Instance, RTN::Instance>(kIllegalCid, isolate_group,
                                              /*register_class=*/true,
                                              /*is_abstract=*/true);
    cls.set_num_type_arguments_unsafe(0);
    cls.set_is_prefinalized();
    RegisterClass(cls, Symbols::Type(), core_lib);
    pending_classes.Add(cls);
    type = Type::NewNonParameterizedType(cls);
    object_store->set_type_type(type);

    // Abstract class that represents the Dart class Function.
    cls = Class::New<Instance, RTN::Instance>(kIllegalCid, isolate_group,
                                              /*register_class=*/true,
                                              /*is_abstract=*/true);
    cls.set_num_type_arguments_unsafe(0);
    cls.set_is_prefinalized();
    RegisterClass(cls, Symbols::Function(), core_lib);
    pending_classes.Add(cls);
    type = Type::NewNonParameterizedType(cls);
    object_store->set_function_type(type);

    // Abstract class that represents the Dart class Record.
    cls = Class::New<Instance, RTN::Instance>(kIllegalCid, isolate_group,
                                              /*register_class=*/true,
                                              /*is_abstract=*/true);
    RegisterClass(cls, Symbols::Record(), core_lib);
    pending_classes.Add(cls);
    object_store->set_record_class(cls);

    cls = Class::New<Number, RTN::Number>(isolate_group);
    RegisterClass(cls, Symbols::Number(), core_lib);
    pending_classes.Add(cls);
    type = Type::NewNonParameterizedType(cls);
    object_store->set_number_type(type);
    type = type.ToNullability(Nullability::kNullable, Heap::kOld);
    object_store->set_nullable_number_type(type);

    cls = Class::New<Instance, RTN::Instance>(kIllegalCid, isolate_group,
                                              /*register_class=*/true,
                                              /*is_abstract=*/true);
    RegisterClass(cls, Symbols::Int(), core_lib);
    cls.set_num_type_arguments_unsafe(0);
    cls.set_is_prefinalized();
    pending_classes.Add(cls);
    type = Type::NewNonParameterizedType(cls);
    object_store->set_int_type(type);
    type = type.ToNullability(Nullability::kNonNullable, Heap::kOld);
    object_store->set_non_nullable_int_type(type);
    type = type.ToNullability(Nullability::kNullable, Heap::kOld);
    object_store->set_nullable_int_type(type);

    cls = Class::New<Instance, RTN::Instance>(kIllegalCid, isolate_group,
                                              /*register_class=*/true,
                                              /*is_abstract=*/true);
    RegisterClass(cls, Symbols::Double(), core_lib);
    cls.set_num_type_arguments_unsafe(0);
    cls.set_is_prefinalized();
    pending_classes.Add(cls);
    type = Type::NewNonParameterizedType(cls);
    object_store->set_double_type(type);
    type = type.ToNullability(Nullability::kNullable, Heap::kOld);
    object_store->set_nullable_double_type(type);

    name = Symbols::_String().ptr();
    cls = Class::New<Instance, RTN::Instance>(kIllegalCid, isolate_group,
                                              /*register_class=*/true,
                                              /*is_abstract=*/true);
    RegisterClass(cls, name, core_lib);
    cls.set_num_type_arguments_unsafe(0);
    cls.set_is_prefinalized();
    pending_classes.Add(cls);
    type = Type::NewNonParameterizedType(cls);
    object_store->set_string_type(type);

    cls = object_store->bool_class();
    type = Type::NewNonParameterizedType(cls);
    object_store->set_bool_type(type);

    cls = object_store->smi_class();
    type = Type::NewNonParameterizedType(cls);
    object_store->set_smi_type(type);

    cls = object_store->mint_class();
    type = Type::NewNonParameterizedType(cls);
    object_store->set_mint_type(type);

    // The classes 'void' and 'dynamic' are phony classes to make type checking
    // more regular; they live in the VM isolate. The class 'void' is not
    // registered in the class dictionary because its name is a reserved word.
    // The class 'dynamic' is registered in the class dictionary because its
    // name is a built-in identifier (this is wrong).  The corresponding types
    // are stored in the object store.
    cls = object_store->null_class();
    type =
        Type::New(cls, Object::null_type_arguments(), Nullability::kNullable);
    type.SetIsFinalized();
    type ^= type.Canonicalize(thread);
    object_store->set_null_type(type);
    cls.set_declaration_type(type);
    ASSERT(type.IsNullable());

    // Consider removing when/if Null becomes an ordinary class.
    type = object_store->object_type();
    cls.set_super_type(type);

    cls = object_store->never_class();
    type = Type::New(cls, Object::null_type_arguments(),
                     Nullability::kNonNullable);
    type.SetIsFinalized();
    type ^= type.Canonicalize(thread);
    object_store->set_never_type(type);
    type_args = TypeArguments::New(1);
    type_args.SetTypeAt(0, type);
    type_args = type_args.Canonicalize(thread);
    object_store->set_type_argument_never(type_args);

    // Create and cache commonly used type arguments <int>, <double>,
    // <String>, <String, dynamic> and <String, String>.
    type_args = TypeArguments::New(1);
    type = object_store->int_type();
    type_args.SetTypeAt(0, type);
    type_args = type_args.Canonicalize(thread);
    object_store->set_type_argument_int(type_args);

    type_args = TypeArguments::New(1);
    type = object_store->double_type();
    type_args.SetTypeAt(0, type);
    type_args = type_args.Canonicalize(thread);
    object_store->set_type_argument_double(type_args);

    type_args = TypeArguments::New(1);
    type = object_store->string_type();
    type_args.SetTypeAt(0, type);
    type_args = type_args.Canonicalize(thread);
    object_store->set_type_argument_string(type_args);

    type_args = TypeArguments::New(2);
    type = object_store->string_type();
    type_args.SetTypeAt(0, type);
    type_args.SetTypeAt(1, Object::dynamic_type());
    type_args = type_args.Canonicalize(thread);
    object_store->set_type_argument_string_dynamic(type_args);

    type_args = TypeArguments::New(2);
    type = object_store->string_type();
    type_args.SetTypeAt(0, type);
    type_args.SetTypeAt(1, type);
    type_args = type_args.Canonicalize(thread);
    object_store->set_type_argument_string_string(type_args);

    lib = Library::LookupLibrary(thread, Symbols::DartFfi());
    if (lib.IsNull()) {
      lib = Library::NewLibraryHelper(Symbols::DartFfi(), true);
      lib.SetLoadRequested();
      lib.Register(thread);
    }
    object_store->set_bootstrap_library(ObjectStore::kFfi, lib);

    cls = Class::New<Instance, RTN::Instance>(kFfiNativeTypeCid, isolate_group);
    cls.set_num_type_arguments_unsafe(0);
    cls.set_is_prefinalized();
    pending_classes.Add(cls);
    object_store->set_ffi_native_type_class(cls);
    RegisterClass(cls, Symbols::FfiNativeType(), lib);

#define REGISTER_FFI_TYPE_MARKER(clazz)                                        \
  cls = Class::New<Instance, RTN::Instance>(kFfi##clazz##Cid, isolate_group);  \
  cls.set_num_type_arguments_unsafe(0);                                        \
  cls.set_is_prefinalized();                                                   \
  pending_classes.Add(cls);                                                    \
  RegisterClass(cls, Symbols::Ffi##clazz(), lib);
    CLASS_LIST_FFI_TYPE_MARKER(REGISTER_FFI_TYPE_MARKER);
#undef REGISTER_FFI_TYPE_MARKER

    cls = Class::New<Instance, RTN::Instance>(kFfiNativeFunctionCid,
                                              isolate_group);
    cls.set_type_arguments_field_offset(Instance::NextFieldOffset(),
                                        RTN::Instance::NextFieldOffset());
    cls.set_num_type_arguments_unsafe(1);
    cls.set_is_prefinalized();
    pending_classes.Add(cls);
    RegisterClass(cls, Symbols::FfiNativeFunction(), lib);

    cls = Class::NewPointerClass(kPointerCid, isolate_group);
    object_store->set_ffi_pointer_class(cls);
    pending_classes.Add(cls);
    RegisterClass(cls, Symbols::FfiPointer(), lib);

    cls = Class::New<DynamicLibrary, RTN::DynamicLibrary>(kDynamicLibraryCid,
                                                          isolate_group);
    cls.set_instance_size(DynamicLibrary::InstanceSize(),
                          compiler::target::RoundedAllocationSize(
                              RTN::DynamicLibrary::InstanceSize()));
    cls.set_is_prefinalized();
    pending_classes.Add(cls);
    RegisterClass(cls, Symbols::FfiDynamicLibrary(), lib);

    cls = Class::New<NativeFinalizer, RTN::NativeFinalizer>(isolate_group);
    object_store->set_native_finalizer_class(cls);
    RegisterPrivateClass(cls, Symbols::_NativeFinalizer(), lib);

    cls = Class::New<Finalizer, RTN::Finalizer>(isolate_group);
    cls.set_type_arguments_field_offset(
        Finalizer::type_arguments_offset(),
        RTN::Finalizer::type_arguments_offset());
    cls.set_num_type_arguments_unsafe(1);
    object_store->set_finalizer_class(cls);
    pending_classes.Add(cls);
    RegisterPrivateClass(cls, Symbols::_FinalizerImpl(), core_lib);

    // Pre-register the internal library so we can place the vm class
    // FinalizerEntry there rather than the core library.
    lib = Library::LookupLibrary(thread, Symbols::DartInternal());
    if (lib.IsNull()) {
      lib = Library::NewLibraryHelper(Symbols::DartInternal(), true);
      lib.SetLoadRequested();
      lib.Register(thread);
    }
    object_store->set_bootstrap_library(ObjectStore::kInternal, lib);
    ASSERT(!lib.IsNull());
    ASSERT(lib.ptr() == Library::InternalLibrary());

    cls = Class::New<FinalizerEntry, RTN::FinalizerEntry>(isolate_group);
    object_store->set_finalizer_entry_class(cls);
    pending_classes.Add(cls);
    RegisterClass(cls, Symbols::FinalizerEntry(), lib);

    // Finish the initialization by compiling the bootstrap scripts containing
    // the base interfaces and the implementation of the internal classes.
    const Error& error = Error::Handle(
        zone, Bootstrap::DoBootstrapping(kernel_buffer, kernel_buffer_size));
    if (!error.IsNull()) {
      return error.ptr();
    }

    isolate_group->class_table()->CopySizesFromClassObjects();

    ClassFinalizer::VerifyBootstrapClasses();

    // Adds static const fields (class ids) to the class 'ClassID');
    lib = Library::LookupLibrary(thread, Symbols::DartInternal());
    ASSERT(!lib.IsNull());
    cls = lib.LookupClassAllowPrivate(Symbols::ClassID());
    ASSERT(!cls.IsNull());
    const bool injected = cls.InjectCIDFields();
    ASSERT(injected);

    // Set up recognized state of all functions (core, math and typed data).
    MethodRecognizer::InitializeState();
#endif  // !defined(DART_PRECOMPILED_RUNTIME)
  } else {
    // Object::Init version when we are running in a version of dart that has a
    // full snapshot linked in and an isolate is initialized using the full
    // snapshot.
    ObjectStore* object_store = isolate_group->object_store();
    SafepointWriteRwLocker ml(thread, isolate_group->program_lock());

    Class& cls = Class::Handle(zone);

    // Set up empty classes in the object store, these will get initialized
    // correctly when we read from the snapshot.  This is done to allow
    // bootstrapping of reading classes from the snapshot.  Some classes are not
    // stored in the object store. Yet we still need to create their Class
    // object so that they get put into the class_table (as a side effect of
    // Class::New()).
    cls = Class::New<Instance, RTN::Instance>(kInstanceCid, isolate_group);
    object_store->set_object_class(cls);

    cls = Class::New<LibraryPrefix, RTN::LibraryPrefix>(isolate_group);
    cls = Class::New<Type, RTN::Type>(isolate_group);
    cls = Class::New<FunctionType, RTN::FunctionType>(isolate_group);
    cls = Class::New<RecordType, RTN::RecordType>(isolate_group);
    cls = Class::New<TypeParameter, RTN::TypeParameter>(isolate_group);

    cls = Class::New<Array, RTN::Array>(isolate_group);
    object_store->set_array_class(cls);

    cls = Class::New<Array, RTN::Array>(kImmutableArrayCid, isolate_group);
    object_store->set_immutable_array_class(cls);

    cls = Class::New<GrowableObjectArray, RTN::GrowableObjectArray>(
        isolate_group);
    object_store->set_growable_object_array_class(cls);

    cls = Class::New<Map, RTN::Map>(isolate_group);
    object_store->set_map_impl_class(cls);

    cls = Class::New<Map, RTN::Map>(kConstMapCid, isolate_group);
    object_store->set_const_map_impl_class(cls);

    cls = Class::New<Set, RTN::Set>(isolate_group);
    object_store->set_set_impl_class(cls);

    cls = Class::New<Set, RTN::Set>(kConstSetCid, isolate_group);
    object_store->set_const_set_impl_class(cls);

    cls = Class::New<Float32x4, RTN::Float32x4>(isolate_group);
    object_store->set_float32x4_class(cls);

    cls = Class::New<Int32x4, RTN::Int32x4>(isolate_group);
    object_store->set_int32x4_class(cls);

    cls = Class::New<Float64x2, RTN::Float64x2>(isolate_group);
    object_store->set_float64x2_class(cls);

#define REGISTER_TYPED_DATA_CLASS(clazz)                                       \
  cls = Class::NewTypedDataClass(kTypedData##clazz##Cid, isolate_group);
    CLASS_LIST_TYPED_DATA(REGISTER_TYPED_DATA_CLASS);
#undef REGISTER_TYPED_DATA_CLASS
#define REGISTER_TYPED_DATA_VIEW_CLASS(clazz)                                  \
  cls =                                                                        \
      Class::NewTypedDataViewClass(kTypedData##clazz##ViewCid, isolate_group); \
  cls = Class::NewUnmodifiableTypedDataViewClass(                              \
      kUnmodifiableTypedData##clazz##ViewCid, isolate_group);
    CLASS_LIST_TYPED_DATA(REGISTER_TYPED_DATA_VIEW_CLASS);
#undef REGISTER_TYPED_DATA_VIEW_CLASS
    cls = Class::NewTypedDataViewClass(kByteDataViewCid, isolate_group);
    cls = Class::NewUnmodifiableTypedDataViewClass(kUnmodifiableByteDataViewCid,
                                                   isolate_group);
#define REGISTER_EXT_TYPED_DATA_CLASS(clazz)                                   \
  cls = Class::NewExternalTypedDataClass(kExternalTypedData##clazz##Cid,       \
                                         isolate_group);
    CLASS_LIST_TYPED_DATA(REGISTER_EXT_TYPED_DATA_CLASS);
#undef REGISTER_EXT_TYPED_DATA_CLASS

    cls = Class::New<Instance, RTN::Instance>(kFfiNativeTypeCid, isolate_group);
    object_store->set_ffi_native_type_class(cls);

#define REGISTER_FFI_CLASS(clazz)                                              \
  cls = Class::New<Instance, RTN::Instance>(kFfi##clazz##Cid, isolate_group);
    CLASS_LIST_FFI_TYPE_MARKER(REGISTER_FFI_CLASS);
#undef REGISTER_FFI_CLASS

    cls = Class::New<Instance, RTN::Instance>(kFfiNativeFunctionCid,
                                              isolate_group);

    cls = Class::NewPointerClass(kPointerCid, isolate_group);
    object_store->set_ffi_pointer_class(cls);

    cls = Class::New<DynamicLibrary, RTN::DynamicLibrary>(kDynamicLibraryCid,
                                                          isolate_group);

    cls = Class::New<Instance, RTN::Instance>(kByteBufferCid, isolate_group,
                                              /*register_isolate_group=*/false);
    cls.set_instance_size_in_words(0, 0);
    isolate_group->class_table()->Register(cls);

    cls = Class::New<Integer, RTN::Integer>(isolate_group);
    object_store->set_integer_implementation_class(cls);

    cls = Class::New<Smi, RTN::Smi>(isolate_group);
    object_store->set_smi_class(cls);

    cls = Class::New<Mint, RTN::Mint>(isolate_group);
    object_store->set_mint_class(cls);

    cls = Class::New<Double, RTN::Double>(isolate_group);
    object_store->set_double_class(cls);

    cls = Class::New<Closure, RTN::Closure>(isolate_group);
    object_store->set_closure_class(cls);

    cls = Class::New<Record, RTN::Record>(isolate_group);

    cls = Class::NewStringClass(kOneByteStringCid, isolate_group);
    object_store->set_one_byte_string_class(cls);

    cls = Class::NewStringClass(kTwoByteStringCid, isolate_group);
    object_store->set_two_byte_string_class(cls);

    cls = Class::New<Bool, RTN::Bool>(isolate_group);
    object_store->set_bool_class(cls);

    cls = Class::New<Instance, RTN::Instance>(kNullCid, isolate_group);
    object_store->set_null_class(cls);

    cls = Class::New<Instance, RTN::Instance>(kNeverCid, isolate_group);
    object_store->set_never_class(cls);

    cls = Class::New<Capability, RTN::Capability>(isolate_group);
    cls = Class::New<ReceivePort, RTN::ReceivePort>(isolate_group);
    cls = Class::New<SendPort, RTN::SendPort>(isolate_group);
    cls = Class::New<StackTrace, RTN::StackTrace>(isolate_group);
    cls = Class::New<SuspendState, RTN::SuspendState>(isolate_group);
    cls = Class::New<RegExp, RTN::RegExp>(isolate_group);
    cls = Class::New<Number, RTN::Number>(isolate_group);

    cls = Class::New<WeakProperty, RTN::WeakProperty>(isolate_group);
    object_store->set_weak_property_class(cls);
    cls = Class::New<WeakReference, RTN::WeakReference>(isolate_group);
    object_store->set_weak_reference_class(cls);
    cls = Class::New<Finalizer, RTN::Finalizer>(isolate_group);
    object_store->set_finalizer_class(cls);
    cls = Class::New<NativeFinalizer, RTN::NativeFinalizer>(isolate_group);
    object_store->set_native_finalizer_class(cls);
    cls = Class::New<FinalizerEntry, RTN::FinalizerEntry>(isolate_group);
    object_store->set_finalizer_entry_class(cls);

    cls = Class::New<MirrorReference, RTN::MirrorReference>(isolate_group);
    c