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 "include/dart_api.h"
#include "platform/assert.h"
#include "vm/assembler.h"
#include "vm/cpu.h"
#include "vm/bigint_operations.h"
#include "vm/bit_vector.h"
#include "vm/bootstrap.h"
#include "vm/class_finalizer.h"
#include "vm/code_generator.h"
#include "vm/code_observers.h"
#include "vm/code_patcher.h"
#include "vm/compiler.h"
#include "vm/compiler_stats.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/disassembler.h"
#include "vm/double_conversion.h"
#include "vm/exceptions.h"
#include "vm/flow_graph_builder.h"
#include "vm/flow_graph_compiler.h"
#include "vm/growable_array.h"
#include "vm/hash_table.h"
#include "vm/heap.h"
#include "vm/intermediate_language.h"
#include "vm/intrinsifier.h"
#include "vm/object_id_ring.h"
#include "vm/object_store.h"
#include "vm/parser.h"
#include "vm/report.h"
#include "vm/reusable_handles.h"
#include "vm/runtime_entry.h"
#include "vm/scopes.h"
#include "vm/stack_frame.h"
#include "vm/symbols.h"
#include "vm/tags.h"
#include "vm/timer.h"
#include "vm/unicode.h"

namespace dart {

DEFINE_FLAG(int, huge_method_cutoff_in_code_size, 200000,
    "Huge method cutoff in unoptimized code size (in bytes).");
DEFINE_FLAG(int, huge_method_cutoff_in_tokens, 20000,
    "Huge method cutoff in tokens: Disables optimizations for huge methods.");
DEFINE_FLAG(bool, overlap_type_arguments, true,
    "When possible, partially or fully overlap the type arguments of a type "
    "with the type arguments of its super type.");
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\")");
DEFINE_FLAG(bool, trace_disabling_optimized_code, false,
    "Trace disabling optimized code.");
DEFINE_FLAG(bool, throw_on_javascript_int_overflow, false,
    "Throw an exception when the result of an integer calculation will not "
    "fit into a javascript integer.");
DEFINE_FLAG(bool, use_field_guards, true, "Guard field cids.");
DEFINE_FLAG(bool, use_lib_cache, true, "Use library name cache");
DEFINE_FLAG(bool, trace_field_guards, false, "Trace changes in field's cids.");

DECLARE_FLAG(bool, enable_type_checks);
DECLARE_FLAG(bool, error_on_bad_override);
DECLARE_FLAG(bool, trace_compiler);
DECLARE_FLAG(bool, trace_deoptimization);
DECLARE_FLAG(bool, trace_deoptimization_verbose);
DECLARE_FLAG(bool, verbose_stacktrace);
DECLARE_FLAG(charp, coverage_dir);
DECLARE_FLAG(bool, write_protect_code);

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

cpp_vtable Object::handle_vtable_ = 0;
cpp_vtable Object::builtin_vtables_[kNumPredefinedCids] = { 0 };
cpp_vtable Smi::handle_vtable_ = 0;

// These are initialized to a value that will force a illegal memory access if
// they are being used.
#if defined(RAW_NULL)
#error RAW_NULL should not be defined.
#endif
#define RAW_NULL kHeapObjectTag
Object* Object::null_object_ = NULL;
Array* Object::null_array_ = NULL;
String* Object::null_string_ = NULL;
Instance* Object::null_instance_ = NULL;
TypeArguments* Object::null_type_arguments_ = NULL;
Array* Object::empty_array_ = NULL;
Array* Object::zero_array_ = NULL;
PcDescriptors* Object::empty_descriptors_ = NULL;
Instance* Object::sentinel_ = NULL;
Instance* Object::transition_sentinel_ = NULL;
Instance* Object::unknown_constant_ = NULL;
Instance* Object::non_constant_ = NULL;
Bool* Object::bool_true_ = NULL;
Bool* Object::bool_false_ = NULL;
Smi* Object::smi_illegal_cid_ = NULL;
LanguageError* Object::snapshot_writer_error_ = NULL;
LanguageError* Object::branch_offset_error_ = NULL;

RawObject* Object::null_ = reinterpret_cast<RawObject*>(RAW_NULL);
RawClass* Object::class_class_ = reinterpret_cast<RawClass*>(RAW_NULL);
RawClass* Object::dynamic_class_ = reinterpret_cast<RawClass*>(RAW_NULL);
RawClass* Object::void_class_ = reinterpret_cast<RawClass*>(RAW_NULL);
RawType* Object::dynamic_type_ = reinterpret_cast<RawType*>(RAW_NULL);
RawType* Object::void_type_ = reinterpret_cast<RawType*>(RAW_NULL);
RawClass* Object::unresolved_class_class_ =
    reinterpret_cast<RawClass*>(RAW_NULL);
RawClass* Object::type_arguments_class_ = reinterpret_cast<RawClass*>(RAW_NULL);
RawClass* Object::patch_class_class_ = reinterpret_cast<RawClass*>(RAW_NULL);
RawClass* Object::function_class_ = reinterpret_cast<RawClass*>(RAW_NULL);
RawClass* Object::closure_data_class_ = reinterpret_cast<RawClass*>(RAW_NULL);
RawClass* Object::redirection_data_class_ =
    reinterpret_cast<RawClass*>(RAW_NULL);
RawClass* Object::field_class_ = reinterpret_cast<RawClass*>(RAW_NULL);
RawClass* Object::literal_token_class_ = reinterpret_cast<RawClass*>(RAW_NULL);
RawClass* Object::token_stream_class_ = reinterpret_cast<RawClass*>(RAW_NULL);
RawClass* Object::script_class_ = reinterpret_cast<RawClass*>(RAW_NULL);
RawClass* Object::library_class_ = reinterpret_cast<RawClass*>(RAW_NULL);
RawClass* Object::namespace_class_ = reinterpret_cast<RawClass*>(RAW_NULL);
RawClass* Object::code_class_ = reinterpret_cast<RawClass*>(RAW_NULL);
RawClass* Object::instructions_class_ = reinterpret_cast<RawClass*>(RAW_NULL);
RawClass* Object::pc_descriptors_class_ = reinterpret_cast<RawClass*>(RAW_NULL);
RawClass* Object::stackmap_class_ = reinterpret_cast<RawClass*>(RAW_NULL);
RawClass* Object::var_descriptors_class_ =
    reinterpret_cast<RawClass*>(RAW_NULL);
RawClass* Object::exception_handlers_class_ =
    reinterpret_cast<RawClass*>(RAW_NULL);
RawClass* Object::deopt_info_class_ = reinterpret_cast<RawClass*>(RAW_NULL);
RawClass* Object::context_class_ = reinterpret_cast<RawClass*>(RAW_NULL);
RawClass* Object::context_scope_class_ = reinterpret_cast<RawClass*>(RAW_NULL);
RawClass* Object::icdata_class_ = reinterpret_cast<RawClass*>(RAW_NULL);
RawClass* Object::megamorphic_cache_class_ =
    reinterpret_cast<RawClass*>(RAW_NULL);
RawClass* Object::subtypetestcache_class_ =
    reinterpret_cast<RawClass*>(RAW_NULL);
RawClass* Object::api_error_class_ = reinterpret_cast<RawClass*>(RAW_NULL);
RawClass* Object::language_error_class_ = reinterpret_cast<RawClass*>(RAW_NULL);
RawClass* Object::unhandled_exception_class_ =
    reinterpret_cast<RawClass*>(RAW_NULL);
RawClass* Object::unwind_error_class_ = reinterpret_cast<RawClass*>(RAW_NULL);


const double MegamorphicCache::kLoadFactor = 0.75;


// The following functions are marked as invisible, meaning they will be hidden
// in the stack trace and will be hidden from reflective access.
// (Library, class name, method name)
// Additionally, private functions in dart:* that are native or constructors are
// marked as invisible by the parser.
#define INVISIBLE_LIST(V)                                                      \
  V(CoreLibrary, int, _throwFormatException)                                   \
  V(CoreLibrary, int, _parse)                                                  \

static void MarkFunctionAsInvisible(const Library& lib,
                                    const char* class_name,
                                    const char* function_name) {
  ASSERT(!lib.IsNull());
  const Class& cls = Class::Handle(
      lib.LookupClassAllowPrivate(String::Handle(String::New(class_name))));
  ASSERT(!cls.IsNull());
  const Function& function =
      Function::Handle(
          cls.LookupFunctionAllowPrivate(
              String::Handle(String::New(function_name))));
  ASSERT(!function.IsNull());
  function.set_is_visible(false);
}


static void MarkInvisibleFunctions() {
#define MARK_FUNCTION(lib, class_name, function_name)                          \
  MarkFunctionAsInvisible(Library::Handle(Library::lib()),                     \
      #class_name, #function_name);                                            \

INVISIBLE_LIST(MARK_FUNCTION)
#undef MARK_FUNCTION
}


// 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@6be832b -> _ReceivePortImpl
//   _ReceivePortImpl@6be832b._internal@6be832b -> _ReceivePortImpl._internal
//   _C@0x2b4ab9cc&_E@0x2b4ab9cc&_F@0x2b4ab9cc -> _C&_E&_F
//
// The trailing . on the default constructor name is dropped:
//
//   List. -> List
//
// And so forth:
//
//   get:foo@6be832b -> foo
//   _MyClass@6b3832b. -> _MyClass
//   _MyClass@6b3832b.named -> _MyClass.named
//
RawString* String::IdentifierPrettyName(const String& name) {
  if (name.Equals(Symbols::TopLevel())) {
    // Name of invisible top-level class.
    return Symbols::Empty().raw();
  }

  // First remove all private name mangling.
  String& unmangled_name = String::Handle(Symbols::Empty().raw());
  String& segment = String::Handle();
  intptr_t start_pos = 0;
  for (intptr_t i = 0; i < name.Length(); i++) {
    if (name.CharAt(i) == '@' &&
        (i+1) < name.Length() &&
        (name.CharAt(i+1) >= '0') &&
        (name.CharAt(i+1) <= '9')) {
      // Append the current segment to the unmangled name.
      segment = String::SubString(name, start_pos, (i - start_pos));
      unmangled_name = String::Concat(unmangled_name, segment);

      // 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.
    }
  }
  if (start_pos == 0) {
    // No name unmangling needed, reuse the name that was passed in.
    unmangled_name = name.raw();
  } else if (name.Length() != start_pos) {
    // Append the last segment.
    segment = String::SubString(name, start_pos, (name.Length() - start_pos));
    unmangled_name = String::Concat(unmangled_name, segment);
  }

  intptr_t len = unmangled_name.Length();
  intptr_t start = 0;
  intptr_t dot_pos = -1;  // Position of '.' in the name, if any.
  bool is_setter = false;
  for (intptr_t i = start; i < len; i++) {
    if (unmangled_name.CharAt(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.CharAt(0) == 's') {
        is_setter = true;
      }
      start = i + 1;
    } else if (unmangled_name.CharAt(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 ((start == 0) && (dot_pos == -1)) {
    // This unmangled_name is fine as it is.
    return unmangled_name.raw();
  }

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

  const String& result =
      String::Handle(String::SubString(unmangled_name, start, (end - start)));

  if (is_setter) {
    // Setters need to end with '='.
    return String::Concat(result, Symbols::Equals());
  }

  return result.raw();
}


RawString* String::IdentifierPrettyNameRetainPrivate(const String& name) {
  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;

  for (intptr_t i = start; i < len; i++) {
    if (name.CharAt(i) == ':') {
      ASSERT(start == 0);  // Only one : is possible in getters or setters.
      if (name.CharAt(0) == '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.raw();
  }

  String& result =
      String::Handle(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.raw();
}


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 bool IsAsciiPrintChar(int32_t code_point) {
  return (code_point >= ' ') && (code_point <= '~');
}


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


static inline bool NeedsEscapeSequence(int32_t c) {
  return (c == '"')  ||
         (c == '\\') ||
         (c == '$')  ||
         IsAsciiNonprintable(c);
}


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';
}


void Object::InitOnce() {
  // TODO(iposva): NoGCScope needs to be added here.
  ASSERT(class_class() == null_);
  // Initialize the static vtable values.
  {
    Object fake_object;
    Smi fake_smi;
    Object::handle_vtable_ = fake_object.vtable();
    Smi::handle_vtable_ = fake_smi.vtable();
  }

  Isolate* isolate = Isolate::Current();
  Heap* heap = isolate->heap();

  // Allocate the read only object handles here.
  null_object_ = Object::ReadOnlyHandle();
  null_array_ = Array::ReadOnlyHandle();
  null_string_ = String::ReadOnlyHandle();
  null_instance_ = Instance::ReadOnlyHandle();
  null_type_arguments_ = TypeArguments::ReadOnlyHandle();
  empty_array_ = Array::ReadOnlyHandle();
  zero_array_ = Array::ReadOnlyHandle();
  empty_descriptors_ = PcDescriptors::ReadOnlyHandle();
  sentinel_ = Instance::ReadOnlyHandle();
  transition_sentinel_ = Instance::ReadOnlyHandle();
  unknown_constant_ =  Instance::ReadOnlyHandle();
  non_constant_ =  Instance::ReadOnlyHandle();
  bool_true_ = Bool::ReadOnlyHandle();
  bool_false_ = Bool::ReadOnlyHandle();
  smi_illegal_cid_ = Smi::ReadOnlyHandle();
  snapshot_writer_error_ = LanguageError::ReadOnlyHandle();
  branch_offset_error_ = LanguageError::ReadOnlyHandle();


  // Allocate and initialize the null instance.
  // 'null_' must be the first object allocated as it is used in allocation to
  // clear the object.
  {
    uword address = heap->Allocate(Instance::InstanceSize(), Heap::kOld);
    null_ = reinterpret_cast<RawInstance*>(address + kHeapObjectTag);
    // The call below is using 'null_' to initialize itself.
    InitializeObject(address, kNullCid, Instance::InstanceSize());
  }

  *null_object_ = Object::null();
  *null_array_ = Array::null();
  *null_string_ = String::null();
  *null_instance_ = Instance::null();
  *null_type_arguments_ = TypeArguments::null();

  // Initialize the empty and zero 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();
  *zero_array_ = Array::null();

  Class& cls = Class::Handle();

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

    Class fake;
    // Initialization from Class::New<Class>.
    // Directly set raw_ to break a circular dependency: SetRaw will attempt
    // to lookup class class in the class table where it is not registered yet.
    cls.raw_ = class_class_;
    cls.set_handle_vtable(fake.vtable());
    cls.set_instance_size(Class::InstanceSize());
    cls.set_next_field_offset(Class::NextFieldOffset());
    cls.set_id(Class::kClassId);
    cls.set_state_bits(0);
    cls.set_is_finalized();
    cls.set_is_type_finalized();
    cls.set_type_arguments_field_offset_in_words(Class::kNoTypeArguments);
    cls.set_num_type_arguments(0);
    cls.set_num_own_type_arguments(0);
    cls.set_num_native_fields(0);
    cls.InitEmptyFields();
    isolate->RegisterClass(cls);
  }

  // Allocate and initialize the null class.
  cls = Class::New<Instance>(kNullCid);
  cls.set_num_type_arguments(0);
  cls.set_num_own_type_arguments(0);
  isolate->object_store()->set_null_class(cls);

  // Allocate and initialize the free list element class.
  cls = Class::New<FreeListElement::FakeInstance>(kFreeListElement);
  cls.set_num_type_arguments(0);
  cls.set_num_own_type_arguments(0);
  cls.set_is_finalized();
  cls.set_is_type_finalized();

  // Allocate and initialize the sentinel values of Null class.
  {
    *sentinel_ ^=
        Object::Allocate(kNullCid, Instance::InstanceSize(), Heap::kOld);

    *transition_sentinel_ ^=
        Object::Allocate(kNullCid, Instance::InstanceSize(), Heap::kOld);
  }

  // Allocate and initialize optimizing compiler constants.
  {
    *unknown_constant_ ^=
        Object::Allocate(kNullCid, Instance::InstanceSize(), Heap::kOld);
    *non_constant_ ^=
        Object::Allocate(kNullCid, Instance::InstanceSize(), Heap::kOld);
  }

  // Allocate the remaining VM internal classes.
  cls = Class::New<UnresolvedClass>();
  unresolved_class_class_ = cls.raw();

  cls = Class::New<TypeArguments>();
  type_arguments_class_ = cls.raw();

  cls = Class::New<PatchClass>();
  patch_class_class_ = cls.raw();

  cls = Class::New<Function>();
  function_class_ = cls.raw();

  cls = Class::New<ClosureData>();
  closure_data_class_ = cls.raw();

  cls = Class::New<RedirectionData>();
  redirection_data_class_ = cls.raw();

  cls = Class::New<Field>();
  field_class_ = cls.raw();

  cls = Class::New<LiteralToken>();
  literal_token_class_ = cls.raw();

  cls = Class::New<TokenStream>();
  token_stream_class_ = cls.raw();

  cls = Class::New<Script>();
  script_class_ = cls.raw();

  cls = Class::New<Library>();
  library_class_ = cls.raw();

  cls = Class::New<Namespace>();
  namespace_class_ = cls.raw();

  cls = Class::New<Code>();
  code_class_ = cls.raw();

  cls = Class::New<Instructions>();
  instructions_class_ = cls.raw();

  cls = Class::New<PcDescriptors>();
  pc_descriptors_class_ = cls.raw();

  cls = Class::New<Stackmap>();
  stackmap_class_ = cls.raw();

  cls = Class::New<LocalVarDescriptors>();
  var_descriptors_class_ = cls.raw();

  cls = Class::New<ExceptionHandlers>();
  exception_handlers_class_ = cls.raw();

  cls = Class::New<DeoptInfo>();
  deopt_info_class_ = cls.raw();

  cls = Class::New<Context>();
  context_class_ = cls.raw();

  cls = Class::New<ContextScope>();
  context_scope_class_ = cls.raw();

  cls = Class::New<ICData>();
  icdata_class_ = cls.raw();

  cls = Class::New<MegamorphicCache>();
  megamorphic_cache_class_ = cls.raw();

  cls = Class::New<SubtypeTestCache>();
  subtypetestcache_class_ = cls.raw();

  cls = Class::New<ApiError>();
  api_error_class_ = cls.raw();

  cls = Class::New<LanguageError>();
  language_error_class_ = cls.raw();

  cls = Class::New<UnhandledException>();
  unhandled_exception_class_ = cls.raw();

  cls = Class::New<UnwindError>();
  unwind_error_class_ = cls.raw();

  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>();
  isolate->object_store()->set_array_class(cls);
  cls.set_type_arguments_field_offset(Array::type_arguments_offset());
  cls.set_num_type_arguments(1);
  cls.set_num_own_type_arguments(1);
  cls = Class::New<Array>(kImmutableArrayCid);
  isolate->object_store()->set_immutable_array_class(cls);
  cls.set_type_arguments_field_offset(Array::type_arguments_offset());
  cls.set_num_type_arguments(1);
  cls.set_num_own_type_arguments(1);
  cls = Class::NewStringClass(kOneByteStringCid);
  isolate->object_store()->set_one_byte_string_class(cls);
  cls = Class::NewStringClass(kTwoByteStringCid);
  isolate->object_store()->set_two_byte_string_class(cls);

  // Allocate and initialize the empty_array instance.
  {
    uword address = heap->Allocate(Array::InstanceSize(0), Heap::kOld);
    InitializeObject(address, kArrayCid, Array::InstanceSize(0));
    Array::initializeHandle(
        empty_array_,
        reinterpret_cast<RawArray*>(address + kHeapObjectTag));
    empty_array_->raw_ptr()->length_ = Smi::New(0);
  }

  // Allocate and initialize the zero_array instance.
  {
    uword address = heap->Allocate(Array::InstanceSize(1), Heap::kOld);
    InitializeObject(address, kArrayCid, Array::InstanceSize(1));
    Array::initializeHandle(
        zero_array_,
        reinterpret_cast<RawArray*>(address + kHeapObjectTag));
    zero_array_->raw_ptr()->length_ = Smi::New(1);
    zero_array_->raw_ptr()->data()[0] = Smi::New(0);
  }

  // Allocate and initialize the empty_descriptors instance.
  {
    uword address = heap->Allocate(PcDescriptors::InstanceSize(0), Heap::kOld);
    InitializeObject(address, kPcDescriptorsCid,
                     PcDescriptors::InstanceSize(0));
    PcDescriptors::initializeHandle(
        empty_descriptors_,
        reinterpret_cast<RawPcDescriptors*>(address + kHeapObjectTag));
    empty_descriptors_->raw_ptr()->length_ = 0;
  }


  cls = Class::New<Instance>(kDynamicCid);
  cls.set_is_abstract();
  cls.set_num_type_arguments(0);
  cls.set_num_own_type_arguments(0);
  cls.set_is_type_finalized();
  cls.set_is_finalized();
  dynamic_class_ = cls.raw();

  cls = Class::New<Instance>(kVoidCid);
  cls.set_num_type_arguments(0);
  cls.set_num_own_type_arguments(0);
  cls.set_is_type_finalized();
  cls.set_is_finalized();
  void_class_ = cls.raw();

  cls = Class::New<Type>();
  cls.set_is_type_finalized();
  cls.set_is_finalized();
  isolate->object_store()->set_type_class(cls);

  cls = dynamic_class_;
  dynamic_type_ = Type::NewNonParameterizedType(cls);

  cls = void_class_;
  void_type_ = Type::NewNonParameterizedType(cls);

  // Allocate and initialize singleton true and false boolean objects.
  cls = Class::New<Bool>();
  isolate->object_store()->set_bool_class(cls);
  *bool_true_ = Bool::New(true);
  *bool_false_ = Bool::New(false);

  *smi_illegal_cid_ = Smi::New(kIllegalCid);

  String& error_str = String::Handle();
  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);

  ASSERT(!null_object_->IsSmi());
  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_type_arguments_->IsSmi());
  ASSERT(null_type_arguments_->IsTypeArguments());
  ASSERT(!empty_array_->IsSmi());
  ASSERT(empty_array_->IsArray());
  ASSERT(!zero_array_->IsSmi());
  ASSERT(zero_array_->IsArray());
  ASSERT(!sentinel_->IsSmi());
  ASSERT(sentinel_->IsInstance());
  ASSERT(!transition_sentinel_->IsSmi());
  ASSERT(transition_sentinel_->IsInstance());
  ASSERT(!unknown_constant_->IsSmi());
  ASSERT(unknown_constant_->IsInstance());
  ASSERT(!non_constant_->IsSmi());
  ASSERT(non_constant_->IsInstance());
  ASSERT(!bool_true_->IsSmi());
  ASSERT(bool_true_->IsBool());
  ASSERT(!bool_false_->IsSmi());
  ASSERT(bool_false_->IsBool());
  ASSERT(smi_illegal_cid_->IsSmi());
  ASSERT(!snapshot_writer_error_->IsSmi());
  ASSERT(snapshot_writer_error_->IsLanguageError());
  ASSERT(!branch_offset_error_->IsSmi());
  ASSERT(branch_offset_error_->IsLanguageError());
}


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

void Object::RegisterSingletonClassNames() {
  Class& cls = Class::Handle();

  // Set up names for all VM singleton classes.
  SET_CLASS_NAME(class, Class);
  SET_CLASS_NAME(dynamic, Dynamic);
  SET_CLASS_NAME(void, Void);
  SET_CLASS_NAME(unresolved_class, UnresolvedClass);
  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(redirection_data, RedirectionData);
  SET_CLASS_NAME(field, Field);
  SET_CLASS_NAME(literal_token, LiteralToken);
  SET_CLASS_NAME(token_stream, TokenStream);
  SET_CLASS_NAME(script, Script);
  SET_CLASS_NAME(library, LibraryClass);
  SET_CLASS_NAME(namespace, Namespace);
  SET_CLASS_NAME(code, Code);
  SET_CLASS_NAME(instructions, Instructions);
  SET_CLASS_NAME(pc_descriptors, PcDescriptors);
  SET_CLASS_NAME(stackmap, Stackmap);
  SET_CLASS_NAME(var_descriptors, LocalVarDescriptors);
  SET_CLASS_NAME(exception_handlers, ExceptionHandlers);
  SET_CLASS_NAME(deopt_info, DeoptInfo);
  SET_CLASS_NAME(context, Context);
  SET_CLASS_NAME(context_scope, ContextScope);
  SET_CLASS_NAME(icdata, ICData);
  SET_CLASS_NAME(megamorphic_cache, MegamorphicCache);
  SET_CLASS_NAME(subtypetestcache, SubtypeTestCache);
  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 object array and one byte string class which are
  // pre-allocated in the vm isolate also.
  cls = Dart::vm_isolate()->object_store()->array_class();
  cls.set_name(Symbols::_List());
  cls = Dart::vm_isolate()->object_store()->one_byte_string_class();
  cls.set_name(Symbols::OneByteString());
}


// 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 an TypedDataInt8Array
// object.
void Object::MakeUnusedSpaceTraversable(const Object& obj,
                                        intptr_t original_size,
                                        intptr_t used_size) {
  ASSERT(Isolate::Current()->no_gc_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 = RawObject::ToAddr(obj.raw()) + used_size;
    if (leftover_size >= TypedData::InstanceSize(0)) {
      // Update the leftover space as an TypedDataInt8Array object.
      RawTypedData* raw =
          reinterpret_cast<RawTypedData*>(RawObject::FromAddr(addr));
      uword tags = 0;
      tags = RawObject::SizeTag::update(leftover_size, tags);
      tags = RawObject::ClassIdTag::update(kTypedDataInt8ArrayCid, tags);
      raw->ptr()->tags_ = tags;
      intptr_t leftover_len = (leftover_size - TypedData::InstanceSize(0));
      ASSERT(TypedData::InstanceSize(leftover_len) == leftover_size);
      raw->ptr()->length_ = Smi::New(leftover_len);
    } else {
      // Update the leftover space as a basic object.
      ASSERT(leftover_size == Object::InstanceSize());
      RawObject* raw = reinterpret_cast<RawObject*>(RawObject::FromAddr(addr));
      uword tags = 0;
      tags = RawObject::SizeTag::update(leftover_size, tags);
      tags = RawObject::ClassIdTag::update(kInstanceCid, tags);
      raw->ptr()->tags_ = tags;
    }
  }
}


void Object::VerifyBuiltinVtables() {
#if defined(DEBUG)
  Isolate* isolate = Isolate::Current();
  ASSERT(isolate != NULL);
  Class& cls = Class::Handle(isolate, Class::null());
  for (intptr_t cid = (kIllegalCid + 1); cid < kNumPredefinedCids; cid++) {
    if (isolate->class_table()->HasValidClassAt(cid)) {
      cls ^= isolate->class_table()->At(cid);
      ASSERT(builtin_vtables_[cid] == cls.raw_ptr()->handle_vtable_);
    }
  }
  ASSERT(builtin_vtables_[kFreeListElement] == 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);
}


RawError* Object::Init(Isolate* isolate) {
  TIMERSCOPE(isolate, time_bootstrap);
  ObjectStore* object_store = isolate->object_store();

  Class& cls = Class::Handle(isolate);
  Type& type = Type::Handle(isolate);
  Array& array = Array::Handle(isolate);
  Library& lib = Library::Handle(isolate);

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

  // Array and ImmutableArray are the only VM classes that are parameterized.
  // Since they are pre-finalized, CalculateFieldOffsets() is not called, so we
  // need to set the offset of their type_arguments_ field, which is explicitly
  // declared in RawArray.
  cls.set_type_arguments_field_offset(Array::type_arguments_offset());
  cls.set_num_type_arguments(1);
  cls.set_num_own_type_arguments(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>();
  object_store->set_growable_object_array_class(cls);
  cls.set_type_arguments_field_offset(
      GrowableObjectArray::type_arguments_offset());
  cls.set_num_type_arguments(1);
  cls.set_num_own_type_arguments(1);

  // canonical_type_arguments_ are Smi terminated.
  // Last element contains the count of used slots.
  const intptr_t kInitialCanonicalTypeArgumentsSize = 4;
  array = Array::New(kInitialCanonicalTypeArgumentsSize + 1);
  array.SetAt(kInitialCanonicalTypeArgumentsSize,
              Smi::Handle(isolate, Smi::New(0)));
  object_store->set_canonical_type_arguments(array);

  // Setup type class early in the process.
  cls = Class::New<Type>();
  object_store->set_type_class(cls);

  cls = Class::New<TypeRef>();
  object_store->set_type_ref_class(cls);

  cls = Class::New<TypeParameter>();
  object_store->set_type_parameter_class(cls);

  cls = Class::New<BoundedType>();
  object_store->set_bounded_type_class(cls);

  cls = Class::New<MixinAppType>();
  object_store->set_mixin_app_type_class(cls);

  cls = Class::New<LibraryPrefix>();
  object_store->set_library_prefix_class(cls);

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

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

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

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

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

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

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

  Context& context = Context::Handle(isolate, Context::New(0, Heap::kOld));
  object_store->set_empty_context(context);

  // 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(isolate);
  cls = object_store->array_class();  // Was allocated above.
  RegisterPrivateClass(cls, Symbols::_List(), core_lib);
  pending_classes.Add(cls);
  // We cannot use NewNonParameterizedType(cls), because Array is parameterized.
  type ^= Type::New(Object::Handle(isolate, cls.raw()),
                    TypeArguments::Handle(isolate),
                    Scanner::kNoSourcePos);
  type.SetIsFinalized();
  type ^= type.Canonicalize();
  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>(kImmutableArrayCid);
  object_store->set_immutable_array_class(cls);
  cls.set_type_arguments_field_offset(Array::type_arguments_offset());
  cls.set_num_type_arguments(1);
  cls.set_num_own_type_arguments(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);

  cls = Class::NewStringClass(kExternalOneByteStringCid);
  object_store->set_external_one_byte_string_class(cls);
  RegisterPrivateClass(cls, Symbols::ExternalOneByteString(), core_lib);
  pending_classes.Add(cls);

  cls = Class::NewStringClass(kExternalTwoByteStringCid);
  object_store->set_external_two_byte_string_class(cls);
  RegisterPrivateClass(cls, Symbols::ExternalTwoByteString(), 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(isolate, Library::LookupLibrary(Symbols::DartIsolate()));
  if (isolate_lib.IsNull()) {
    isolate_lib = Library::NewLibraryHelper(Symbols::DartIsolate(), true);
    isolate_lib.SetLoadRequested();
    isolate_lib.Register();
    isolate->object_store()->set_bootstrap_library(ObjectStore::kIsolate,
                                                   isolate_lib);
  }
  ASSERT(!isolate_lib.IsNull());
  ASSERT(isolate_lib.raw() == Library::IsolateLibrary());

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

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

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

  cls = Class::New<Stacktrace>();
  object_store->set_stacktrace_class(cls);
  RegisterClass(cls, Symbols::StackTrace(), core_lib);
  pending_classes.Add(cls);
  // Super type set below, after Object is allocated.

  cls = Class::New<JSRegExp>();
  RegisterPrivateClass(cls, Symbols::JSSyntaxRegExp(), 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 in
  // the parser when the corelib script is compiled (see
  // Parser::ParseClassDefinition).
  cls = Class::New<Instance>(kInstanceCid);
  object_store->set_object_class(cls);
  cls.set_name(Symbols::Object());
  cls.set_num_type_arguments(0);
  cls.set_num_own_type_arguments(0);
  cls.set_is_prefinalized();
  core_lib.AddClass(cls);
  pending_classes.Add(cls);
  type = Type::NewNonParameterizedType(cls);
  object_store->set_object_type(type);

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

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

  cls = object_store->library_prefix_class();
  ASSERT(!cls.IsNull());
  RegisterPrivateClass(cls, Symbols::_LibraryPrefix(), core_lib);
  pending_classes.Add(cls);

  cls = object_store->type_class();
  RegisterPrivateClass(cls, Symbols::Type(), core_lib);
  pending_classes.Add(cls);

  cls = object_store->type_ref_class();
  RegisterPrivateClass(cls, Symbols::TypeRef(), core_lib);
  pending_classes.Add(cls);

  cls = object_store->type_parameter_class();
  RegisterPrivateClass(cls, Symbols::TypeParameter(), core_lib);
  pending_classes.Add(cls);

  cls = object_store->bounded_type_class();
  RegisterPrivateClass(cls, Symbols::BoundedType(), core_lib);
  pending_classes.Add(cls);

  cls = object_store->mixin_app_type_class();
  RegisterPrivateClass(cls, Symbols::MixinAppType(), core_lib);
  pending_classes.Add(cls);

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

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

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

  cls = Class::New<Bigint>();
  object_store->set_bigint_class(cls);
  RegisterPrivateClass(cls, Symbols::_Bigint(), core_lib);
  pending_classes.Add(cls);

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

  // Abstract super class for all signature classes.
  cls = Class::New<Instance>(kIllegalCid);
  cls.set_num_type_arguments(0);
  cls.set_num_own_type_arguments(0);
  cls.set_is_prefinalized();
  RegisterPrivateClass(cls, Symbols::FunctionImpl(), core_lib);
  pending_classes.Add(cls);
  type = Type::NewNonParameterizedType(cls);
  object_store->set_function_impl_type(type);

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

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

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

  // Pre-register the profiler library so we can place the vm class
  // UserTag there rather than the core library.
  lib = Library::LookupLibrary(Symbols::DartProfiler());
  if (lib.IsNull()) {
    lib = Library::NewLibraryHelper(Symbols::DartProfiler(), true);
    lib.SetLoadRequested();
    lib.Register();
    isolate->object_store()->set_bootstrap_library(ObjectStore::kProfiler,
                                                   lib);
  }
  ASSERT(!lib.IsNull());
  ASSERT(lib.raw() == Library::ProfilerLibrary());

  lib = Library::LookupLibrary(Symbols::DartProfiler());
  ASSERT(!lib.IsNull());
  cls = Class::New<UserTag>();
  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);
  ASSERT(isolate->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(Symbols::DartTypedData());
  if (lib.IsNull()) {
    lib = Library::NewLibraryHelper(Symbols::DartTypedData(), true);
    lib.SetLoadRequested();
    lib.Register();
    isolate->object_store()->set_bootstrap_library(ObjectStore::kTypedData,
                                                   lib);
  }
  ASSERT(!lib.IsNull());
  ASSERT(lib.raw() == Library::TypedDataLibrary());
  const intptr_t typed_data_class_array_length =
      RawObject::NumberOfTypedDataClasses();
  Array& typed_data_classes =
      Array::Handle(Array::New(typed_data_class_array_length));
  int index = 0;
#define REGISTER_TYPED_DATA_CLASS(clazz)                                       \
  cls = Class::NewTypedDataClass(kTypedData##clazz##Cid);                      \
  index = kTypedData##clazz##Cid - kTypedDataInt8ArrayCid;                     \
  typed_data_classes.SetAt(index, cls);                                        \
  RegisterPrivateClass(cls, Symbols::_##clazz(), lib);                         \

  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);              \
  index = kTypedData##clazz##ViewCid - kTypedDataInt8ArrayCid;                 \
  typed_data_classes.SetAt(index, cls);                                        \
  RegisterPrivateClass(cls, Symbols::_##clazz##View(), lib);                   \
  pending_classes.Add(cls);                                                    \

  CLASS_LIST_TYPED_DATA(REGISTER_TYPED_DATA_VIEW_CLASS);
  cls = Class::NewTypedDataViewClass(kByteDataViewCid);
  index = kByteDataViewCid - kTypedDataInt8ArrayCid;
  typed_data_classes.SetAt(index, cls);
  RegisterPrivateClass(cls, Symbols::_ByteDataView(), lib);
  pending_classes.Add(cls);
#undef REGISTER_TYPED_DATA_VIEW_CLASS
#define REGISTER_EXT_TYPED_DATA_CLASS(clazz)                                   \
  cls = Class::NewExternalTypedDataClass(kExternalTypedData##clazz##Cid);      \
  index = kExternalTypedData##clazz##Cid - kTypedDataInt8ArrayCid;             \
  typed_data_classes.SetAt(index, cls);                                        \
  RegisterPrivateClass(cls, Symbols::_External##clazz(), lib);                 \

  CLASS_LIST_TYPED_DATA(REGISTER_EXT_TYPED_DATA_CLASS);
#undef REGISTER_EXT_TYPED_DATA_CLASS
  // Register Float32x4 and Int32x4 in the object store.
  cls = Class::New<Float32x4>();
  object_store->set_float32x4_class(cls);
  RegisterPrivateClass(cls, Symbols::_Float32x4(), lib);
  cls = Class::New<Int32x4>();
  object_store->set_int32x4_class(cls);
  RegisterPrivateClass(cls, Symbols::_Int32x4(), lib);
  cls = Class::New<Float64x2>();
  object_store->set_float64x2_class(cls);
  RegisterPrivateClass(cls, Symbols::_Float64x2(), lib);

  cls = Class::New<Instance>(kIllegalCid);
  RegisterClass(cls, Symbols::Float32x4(), lib);
  cls.set_num_type_arguments(0);
  cls.set_num_own_type_arguments(0);
  cls.set_is_prefinalized();
  pending_classes.Add(cls);
  type = Type::NewNonParameterizedType(cls);
  object_store->set_float32x4_type(type);

  cls = Class::New<Instance>(kIllegalCid);
  RegisterClass(cls, Symbols::Int32x4(), lib);
  cls.set_num_type_arguments(0);
  cls.set_num_own_type_arguments(0);
  cls.set_is_prefinalized();
  pending_classes.Add(cls);
  type = Type::NewNonParameterizedType(cls);
  object_store->set_int32x4_type(type);

  cls = Class::New<Instance>(kIllegalCid);
  RegisterClass(cls, Symbols::Float64x2(), lib);
  cls.set_num_type_arguments(0);
  cls.set_num_own_type_arguments(0);
  cls.set_is_prefinalized();
  pending_classes.Add(cls);
  type = Type::NewNonParameterizedType(cls);
  object_store->set_float64x2_type(type);

  object_store->set_typed_data_classes(typed_data_classes);

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

  // Abstract class that represents the Dart class Function.
  cls = Class::New<Instance>(kIllegalCid);
  cls.set_num_type_arguments(0);
  cls.set_num_own_type_arguments(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);

  cls = Class::New<Number>();
  RegisterClass(cls, Symbols::Number(), core_lib);
  pending_classes.Add(cls);
  type = Type::NewNonParameterizedType(cls);
  object_store->set_number_type(type);

  cls = Class::New<Instance>(kIllegalCid);
  RegisterClass(cls, Symbols::Int(), core_lib);
  cls.set_num_type_arguments(0);
  cls.set_num_own_type_arguments(0);
  cls.set_is_prefinalized();
  pending_classes.Add(cls);
  type = Type::NewNonParameterizedType(cls);
  object_store->set_int_type(type);

  cls = Class::New<Instance>(kIllegalCid);
  RegisterClass(cls, Symbols::Double(), core_lib);
  cls.set_num_type_arguments(0);
  cls.set_num_own_type_arguments(0);
  cls.set_is_prefinalized();
  pending_classes.Add(cls);
  type = Type::NewNonParameterizedType(cls);
  object_store->set_double_type(type);

  name = Symbols::New("String");
  cls = Class::New<Instance>(kIllegalCid);
  RegisterClass(cls, name, core_lib);
  cls.set_num_type_arguments(0);
  cls.set_num_own_type_arguments(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 phoney 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::NewNonParameterizedType(cls);
  object_store->set_null_type(type);

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

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

  ClassFinalizer::VerifyBootstrapClasses();
  MarkInvisibleFunctions();

  // Set up the intrinsic state of all functions (core, math and typed data).
  Intrinsifier::InitializeState();

  // Set up recognized state of all functions (core, math and typed data).
  MethodRecognizer::InitializeState();

  // Adds static const fields (class ids) to the class 'ClassID');
  lib = Library::LookupLibrary(Symbols::DartInternal());
  ASSERT(!lib.IsNull());
  cls = lib.LookupClassAllowPrivate(Symbols::ClassID());
  ASSERT(!cls.IsNull());
  Field& field = Field::Handle(isolate);
  Smi& value = Smi::Handle(isolate);
  String& field_name = String::Handle(isolate);

#define CLASS_LIST_WITH_NULL(V)                                                \
  V(Null)                                                                      \
  CLASS_LIST_NO_OBJECT(V)

#define ADD_SET_FIELD(clazz)                                                   \
  field_name = Symbols::New("cid"#clazz);                                      \
  field = Field::New(field_name, true, false, true, false, cls, 0);            \
  value = Smi::New(k##clazz##Cid);                                             \
  field.set_value(value);                                                      \
  field.set_type(Type::Handle(Type::IntType()));                               \
  cls.AddField(field);                                                         \

  CLASS_LIST_WITH_NULL(ADD_SET_FIELD)
#undef ADD_SET_FIELD

  return Error::null();
}


void Object::InitFromSnapshot(Isolate* isolate) {
  TIMERSCOPE(isolate, time_bootstrap);
  ObjectStore* object_store = isolate->object_store();

  Class& cls = Class::Handle();

  // 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.
  cls = Class::New<Instance>(kInstanceCid);
  object_store->set_object_class(cls);

  cls = Class::New<LibraryPrefix>();
  object_store->set_library_prefix_class(cls);

  cls = Class::New<Type>();
  object_store->set_type_class(cls);

  cls = Class::New<TypeRef>();
  object_store->set_type_ref_class(cls);

  cls = Class::New<TypeParameter>();
  object_store->set_type_parameter_class(cls);

  cls = Class::New<BoundedType>();
  object_store->set_bounded_type_class(cls);

  cls = Class::New<MixinAppType>();
  object_store->set_mixin_app_type_class(cls);

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

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

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

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

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

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

#define REGISTER_TYPED_DATA_CLASS(clazz)                                       \
  cls = Class::NewTypedDataClass(kTypedData##clazz##Cid);
  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);
  CLASS_LIST_TYPED_DATA(REGISTER_TYPED_DATA_VIEW_CLASS);
  cls = Class::NewTypedDataViewClass(kByteDataViewCid);
#undef REGISTER_TYPED_DATA_VIEW_CLASS
#define REGISTER_EXT_TYPED_DATA_CLASS(clazz)                                   \
  cls = Class::NewExternalTypedDataClass(kExternalTypedData##clazz##Cid);
  CLASS_LIST_TYPED_DATA(REGISTER_EXT_TYPED_DATA_CLASS);
#undef REGISTER_EXT_TYPED_DATA_CLASS

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

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

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

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

  cls = Class::New<Bigint>();
  object_store->set_bigint_class(cls);

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

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

  cls = Class::NewStringClass(kExternalOneByteStringCid);
  object_store->set_external_one_byte_string_class(cls);

  cls = Class::NewStringClass(kExternalTwoByteStringCid);
  object_store->set_external_two_byte_string_class(cls);

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

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

  cls = Class::New<Capability>();
  cls = Class::New<ReceivePort>();
  cls = Class::New<SendPort>();

  cls = Class::New<Stacktrace>();
  object_store->set_stacktrace_class(cls);

  cls = Class::New<JSRegExp>();

  // 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<Number>();

  cls = Class::New<WeakProperty>();
  object_store->set_weak_property_class(cls);

  cls = Class::New<MirrorReference>();

  cls = Class::New<UserTag>();
}


void Object::Print() const {
  OS::Print("%s\n", ToCString());
}


void Object::PrintJSON(JSONStream* stream, bool ref) const {
  if (IsNull()) {
    JSONObject jsobj(stream);
    jsobj.AddProperty("type", ref ? "@Null" : "Null");
    jsobj.AddProperty("id", "objects/null");
    jsobj.AddProperty("valueAsString", "null");
  } else {
    PrintJSONImpl(stream, ref);
  }
}


RawString* Object::DictionaryName() const {
  return String::null();
}


void Object::InitializeObject(uword address, intptr_t class_id, intptr_t size) {
  // TODO(iposva): Get a proper halt instruction from the assembler which
  // would be needed here for code objects.
  uword initial_value = reinterpret_cast<uword>(null_);
  uword cur = address;
  uword end = address + size;
  while (cur < end) {
    *reinterpret_cast<uword*>(cur) = initial_value;
    cur += kWordSize;
  }
  uword tags = 0;
  ASSERT(class_id != kIllegalCid);
  tags = RawObject::ClassIdTag::update(class_id, tags);
  tags = RawObject::SizeTag::update(size, tags);
  reinterpret_cast<RawObject*>(address)->tags_ = tags;
}


void Object::CheckHandle() const {
#if defined(DEBUG)
  if (raw_ != Object::null()) {
    if ((reinterpret_cast<uword>(raw_) & kSmiTagMask) == kSmiTag) {
      ASSERT(vtable() == Smi::handle_vtable_);
      return;
    }
    intptr_t cid = raw_->GetClassId();
    if (cid >= kNumPredefinedCids) {
      cid = kInstanceCid;
    }
    ASSERT(vtable() == builtin_vtables_[cid]);
    if (FLAG_verify_handles) {
      Isolate* isolate = Isolate::Current();
      Heap* isolate_heap = isolate->heap();
      Heap* vm_isolate_heap = Dart::vm_isolate()->heap();
      ASSERT(isolate_heap->Contains(RawObject::ToAddr(raw_)) ||
             vm_isolate_heap->Contains(RawObject::ToAddr(raw_)));
    }
  }
#endif
}


RawObject* Object::Allocate(intptr_t cls_id,
                            intptr_t size,
                            Heap::Space space) {
  ASSERT(Utils::IsAligned(size, kObjectAlignment));
  Isolate* isolate = Isolate::Current();
  ASSERT(isolate->no_callback_scope_depth() == 0);
  Heap* heap = isolate->heap();

  uword address = heap->Allocate(size, space);
  if (address == 0) {
    // Use the preallocated out of memory exception to avoid calling
    // into dart code or allocating any code.
    const Instance& exception =
        Instance::Handle(isolate->object_store()->out_of_memory());
    Exceptions::Throw(isolate, exception);
    UNREACHABLE();
  }
  if (space == Heap::kNew) {
    isolate->class_table()->UpdateAllocatedNew(cls_id, size);
  } else {
    isolate->class_table()->UpdateAllocatedOld(cls_id, size);
  }
  NoGCScope no_gc;
  InitializeObject(address, cls_id, size);
  RawObject* raw_obj = reinterpret_cast<RawObject*>(address + kHeapObjectTag);
  ASSERT(cls_id == RawObject::ClassIdTag::decode(raw_obj->ptr()->tags_));
  return raw_obj;
}


class StoreBufferUpdateVisitor : public ObjectPointerVisitor {
 public:
  explicit StoreBufferUpdateVisitor(Isolate* isolate, RawObject* obj) :
      ObjectPointerVisitor(isolate), old_obj_(obj) {
    ASSERT(old_obj_->IsOldObject());
  }

  void VisitPointers(RawObject** first, RawObject** last) {
    for (RawObject** curr = first; curr <= last; ++curr) {
      RawObject* raw_obj = *curr;
      if (raw_obj->IsHeapObject() && raw_obj->IsNewObject()) {
        old_obj_->SetRememberedBit();
        isolate()->store_buffer()->AddObject(old_obj_);
        // Remembered this object. There is no need to continue searching.
        return;
      }
    }
  }

 private:
  RawObject* old_obj_;

  DISALLOW_COPY_AND_ASSIGN(StoreBufferUpdateVisitor);
};


bool Object::IsReadOnlyHandle() const {
  return Dart::IsReadOnlyHandle(reinterpret_cast<uword>(this));
}


bool Object::IsNotTemporaryScopedHandle() const {
  return (IsZoneHandle() || IsReadOnlyHandle());
}



RawObject* Object::Clone(const Object& src, Heap::Space space) {
  const Class& cls = Class::Handle(src.clazz());
  intptr_t size = src.raw()->Size();
  RawObject* raw_obj = Object::Allocate(cls.id(), size, space);
  NoGCScope no_gc;
  memmove(raw_obj->ptr(), src.raw()->ptr(), size);
  if ((space == Heap::kOld) && !raw_obj->IsRemembered()) {
    StoreBufferUpdateVisitor visitor(Isolate::Current(), raw_obj);
    raw_obj->VisitPointers(&visitor);
  }
  return raw_obj;
}


RawString* Class::Name() const {
  // TODO(turnidge): This assert fails for the fake kFreeListElement class.
  // Fix this.
  ASSERT(raw_ptr()->name_ != String::null());
  return raw_ptr()->name_;
}


RawString* Class::PrettyName() const {
  return GeneratePrettyName();
}


RawString* Class::UserVisibleName() const {
  ASSERT(raw_ptr()->user_name_ != String::null());
  return raw_ptr()->user_name_;
}


RawType* Class::SignatureType() const {
  ASSERT(IsSignatureClass());
  const Function& function = Function::Handle(signature_function());
  ASSERT(!function.IsNull());
  if (function.signature_class() != raw()) {
    // This class is a function type alias. Return the canonical signature type.
    const Class& canonical_class = Class::Handle(function.signature_class());
    return canonical_class.SignatureType();
  }
  // Return the first canonical signature type if already computed at class
  // finalization time. The optimizer may canonicalize instantiated function
  // types of the same signature class, but these will be added after the
  // uninstantiated signature class at index 0.
  Array& signature_types = Array::Handle();
  signature_types ^= canonical_types();
  if (signature_types.IsNull()) {
    set_canonical_types(empty_array());
    signature_types ^= canonical_types();
  }
  // The canonical_types array is initialized to the empty array.
  ASSERT(!signature_types.IsNull());
  if (signature_types.Length() > 0) {
    Type& signature_type = Type::Handle();
    signature_type ^= signature_types.At(0);
    ASSERT(!signature_type.IsNull());
    return signature_type.raw();
  }
  // A signature class extends class Instance and is parameterized in the same
  // way as the owner class of its non-static signature function.
  // It is not type parameterized if its signature function is static.
  // See Class::NewSignatureClass() for the setup of its type parameters.
  // During type finalization, the type arguments of the super class of the
  // owner class of its signature function will be prepended to the type
  // argument vector. Therefore, we only need to set the type arguments
  // matching the type parameters here.
  const TypeArguments& signature_type_arguments =
      TypeArguments::Handle(type_parameters());
  const Type& signature_type = Type::Handle(
      Type::New(*this, signature_type_arguments, token_pos()));

  // Return the still unfinalized signature type.
  ASSERT(!signature_type.IsFinalized());
  return signature_type.raw();
}


RawAbstractType* Class::RareType() const {
  const Type& type = Type::Handle(Type::New(
      *this,
      Object::null_type_arguments(),
      Scanner::kNoSourcePos));
  return ClassFinalizer::FinalizeType(*this,
                                      type,
                                      ClassFinalizer::kCanonicalize);
}


RawAbstractType* Class::DeclarationType() const {
  const TypeArguments& args = TypeArguments::Handle(type_parameters());
  const Type& type = Type::Handle(Type::New(
      *this,
      args,
      Scanner::kNoSourcePos));
  return ClassFinalizer::FinalizeType(*this,
                                      type,
                                      ClassFinalizer::kCanonicalize);
}


template <class FakeObject>
RawClass* Class::New() {
  ASSERT(Object::class_class() != Class::null());
  Class& result = Class::Handle();
  {
    RawObject* raw = Object::Allocate(Class::kClassId,
                                      Class::InstanceSize(),
                                      Heap::kOld);
    NoGCScope no_gc;
    result ^= raw;
  }
  FakeObject fake;
  result.set_handle_vtable(fake.vtable());
  result.set_instance_size(FakeObject::InstanceSize());
  result.set_next_field_offset(FakeObject::NextFieldOffset());
  COMPILE_ASSERT((FakeObject::kClassId != kInstanceCid));
  result.set_id(FakeObject::kClassId);
  result.set_state_bits(0);
  if (FakeObject::kClassId < kInstanceCid) {
    // VM internal classes are done. There is no finalization needed or
    // possible in this case.
    result.set_is_finalized();
  } else {
    // VM backed classes are almost ready: run checks and resolve class
    // references, but do not recompute size.
    result.set_is_prefinalized();
  }
  result.set_type_arguments_field_offset_in_words(kNoTypeArguments);
  result.set_num_type_arguments(0);
  result.set_num_own_type_arguments(0);
  result.set_num_native_fields(0);
  result.set_token_pos(Scanner::kNoSourcePos);
  result.InitEmptyFields();
  Isolate::Current()->RegisterClass(result);
  return result.raw();
}



static void ReportTooManyTypeArguments(const Class& cls) {
  Report::MessageF(Report::kError,
                   Script::Handle(cls.script()),
                   cls.token_pos(),
                   "too many type parameters declared in class '%s' or in its "
                   "super classes",
                   String::Handle(cls.Name()).ToCString());
  UNREACHABLE();
}


void Class::set_num_type_arguments(intptr_t value) const {
  if (!Utils::IsInt(16, value)) {
    ReportTooManyTypeArguments(*this);
  }
  raw_ptr()->num_type_arguments_ = value;
}


void Class::set_num_own_type_arguments(intptr_t value) const {
  if (!Utils::IsInt(16, value)) {
    ReportTooManyTypeArguments(*this);
  }
  raw_ptr()->num_own_type_arguments_ = value;
}


// Initialize class fields of type Array with empty array.
void Class::InitEmptyFields() {
  if (Object::empty_array().raw() == Array::null()) {
    // The empty array has not been initialized yet.
    return;
  }
  StorePointer(&raw_ptr()->interfaces_, Object::empty_array().raw());
  StorePointer(&raw_ptr()->constants_, Object::empty_array().raw());
  StorePointer(&raw_ptr()->functions_, Object::empty_array().raw());
  StorePointer(&raw_ptr()->fields_, Object::empty_array().raw());
  StorePointer(&raw_ptr()->invocation_dispatcher_cache_,
               Object::empty_array().raw());
}


RawArray* Class::OffsetToFieldMap() const {
  Array& array = Array::Handle(raw_ptr()->offset_in_words_to_field_);
  if (array.IsNull()) {
    ASSERT(is_finalized());
    const intptr_t length = raw_ptr()->instance_size_in_words_;
    array = Array::New(length, Heap::kOld);
    Class& cls = Class::Handle(this->raw());
    Array& fields = Array::Handle();
    Field& f = Field::Handle();
    while (!cls.IsNull()) {
      fields = cls.fields();
      for (intptr_t i = 0; i < fields.Length(); ++i) {
        f ^= fields.At(i);
        if (!f.is_static()) {
          array.SetAt(f.Offset() >> kWordSizeLog2, f);
        }
      }
      cls = cls.SuperClass();
    }
    StorePointer(&raw_ptr()->offset_in_words_to_field_, array.raw());
  }
  return array.raw();
}


bool Class::HasInstanceFields() const {
  const Array& field_array = Array::Handle(fields());
  Field& field = Field::Handle();
  for (intptr_t i = 0; i < field_array.Length(); ++i) {
    field ^= field_array.At(i);
    if (!field.is_static()) {
      return true;
    }
  }
  return false;
}


void Class::SetFunctions(const Array& value) const {
  ASSERT(!value.IsNull());
#if defined(DEBUG)
  // Verify that all the functions in the array have this class as owner.
  Function& func = Function::Handle();
  intptr_t len = value.Length();
  for (intptr_t i = 0; i < len; i++) {
    func ^= value.At(i);
    ASSERT(func.Owner() == raw());
  }
#endif
  StorePointer(&raw_ptr()->functions_, value.raw());
}


void Class::AddFunction(const Function& function) const {
  const Array& arr = Array::Handle(functions());
  const Array& new_arr = Array::Handle(Array::Grow(arr, arr.Length() + 1));
  new_arr.SetAt(arr.Length(), function);
  SetFunctions(new_arr);
}


intptr_t Class::FindFunctionIndex(const Function& needle) const {
  Isolate* isolate = Isolate::Current();
  if (EnsureIsFinalized(isolate) != Error::null()) {
    return -1;
  }
  REUSABLE_ARRAY_HANDLESCOPE(isolate);
  REUSABLE_FUNCTION_HANDLESCOPE(isolate);
  Array& funcs = isolate->ArrayHandle();
  Function& function = isolate->FunctionHandle();
  funcs ^= functions();
  ASSERT(!funcs.IsNull());
  const intptr_t len = funcs.Length();
  for (intptr_t i = 0; i < len; i++) {
    function ^= funcs.At(i);
    if (function.raw() == needle.raw()) {
      return i;
    }
  }
  // No function found.
  return -1;
}


RawFunction* Class::FunctionFromIndex(intptr_t idx) const {
  const Array& funcs = Array::Handle(functions());
  if ((idx < 0) || (idx >= funcs.Length())) {
    return Function::null();
  }
  Function& func = Function::Handle();
  func ^= funcs.At(idx);
  ASSERT(!func.IsNull());
  return func.raw();
}


RawFunction* Class::ImplicitClosureFunctionFromIndex(intptr_t idx) const {
  const Array& funcs = Array::Handle(functions());
  if ((idx < 0) || (idx >= funcs.Length())) {
    return Function::null();
  }
  Function& func = Function::Handle();
  func ^= funcs.At(idx);
  ASSERT(!func.IsNull());
  if (!func.HasImplicitClosureFunction()) {
    return Function::null();
  }
  const Function& closure_func =
      Function::Handle(func.ImplicitClosureFunction());
  ASSERT(!closure_func.IsNull());
  return closure_func.raw();
}


intptr_t Class::FindImplicitClosureFunctionIndex(const Function& needle) const {
  Isolate* isolate = Isolate::Current();
  if (EnsureIsFinalized(isolate) != Error::null()) {
    return -1;
  }
  REUSABLE_ARRAY_HANDLESCOPE(isolate);
  REUSABLE_FUNCTION_HANDLESCOPE(isolate);
  Array& funcs = isolate->ArrayHandle();
  Function& function = isolate->FunctionHandle();
  funcs ^= functions();
  ASSERT(!funcs.IsNull());
  Function& implicit_closure = Function::Handle(isolate);
  const intptr_t len = funcs.Length();
  for (intptr_t i = 0; i < len; i++) {
    function ^= funcs.At(i);
    implicit_closure ^= function.implicit_closure_function();
    if (implicit_closure.IsNull()) {
      // Skip non-implicit closure functions.
      continue;
    }
    if (needle.raw() == implicit_closure.raw()) {
      return i;
    }
  }
  // No function found.
  return -1;
}



intptr_t Class::FindInvocationDispatcherFunctionIndex(
    const Function& needle) const {
  Isolate* isolate = Isolate::Current();
  if (EnsureIsFinalized(isolate) != Error::null()) {
    return -1;
  }
  REUSABLE_ARRAY_HANDLESCOPE(isolate);
  REUSABLE_OBJECT_HANDLESCOPE(isolate);
  Array& funcs = isolate->ArrayHandle();
  Object& object = isolate->ObjectHandle();
  funcs ^= invocation_dispatcher_cache();
  ASSERT(!funcs.IsNull());
  const intptr_t len = funcs.Length();
  for (intptr_t i = 0; i < len; i++) {
    object = funcs.At(i);
    // The invocation_dispatcher_cache is a table with some entries that
    // are functions.
    if (object.IsFunction()) {
      if (Function::Cast(object).raw() == needle.raw()) {
        return i;
      }
    }
  }
  // No function found.
  return -1;
}



RawFunction* Class::InvocationDispatcherFunctionFromIndex(intptr_t idx) const {
  Isolate* isolate = Isolate::Current();
  REUSABLE_ARRAY_HANDLESCOPE(isolate);
  REUSABLE_OBJECT_HANDLESCOPE(isolate);
  Array& dispatcher_cache = isolate->ArrayHandle();
  Object& object = isolate->ObjectHandle();
  dispatcher_cache ^= invocation_dispatcher_cache();
  object = dispatcher_cache.At(idx);
  if (!object.IsFunction()) {
    return Function::null();
  }
  return Function::Cast(object).raw();
}


void Class::AddClosureFunction(const Function& function) const {
  GrowableObjectArray& closures =
      GrowableObjectArray::Handle(raw_ptr()->closure_functions_);
  if (closures.IsNull()) {
    closures = GrowableObjectArray::New(4);
    StorePointer(&raw_ptr()->closure_functions_, closures.raw());
  }
  ASSERT(function.IsNonImplicitClosureFunction());
  ASSERT(function.Owner() == this->raw());
  closures.Add(function);
}


// Lookup the innermost closure function that contains token at token_pos.
RawFunction* Class::LookupClosureFunction(intptr_t token_pos) const {
  if (raw_ptr()->closure_functions_ == GrowableObjectArray::null()) {
    return Function::null();
  }
  const GrowableObjectArray& closures =
      GrowableObjectArray::Handle(raw_ptr()->closure_functions_);
  Function& closure = Function::Handle();
  intptr_t num_closures = closures.Length();
  intptr_t best_fit_token_pos = -1;
  intptr_t best_fit_index = -1;
  for (intptr_t i = 0; i < num_closures; i++) {
    closure ^= closures.At(i);
    ASSERT(!closure.IsNull());
    if ((closure.token_pos() <= token_pos) &&
        (token_pos <= closure.end_token_pos()) &&
        (best_fit_token_pos < closure.token_pos())) {
      best_fit_index = i;
      best_fit_token_pos = closure.token_pos();
    }
  }
  closure = Function::null();
  if (best_fit_index >= 0) {
    closure ^= closures.At(best_fit_index);
  }
  return closure.raw();
}

intptr_t Class::FindClosureIndex(const Function& needle) const {
  if (closures() == GrowableObjectArray::null()) {
    return -1;
  }
  Isolate* isolate = Isolate::Current();
  const GrowableObjectArray& closures_array =
      GrowableObjectArray::Handle(isolate, closures());
  REUSABLE_FUNCTION_HANDLESCOPE(isolate);
  Function& closure = isolate->FunctionHandle();
  intptr_t num_closures = closures_array.Length();
  for (intptr_t i = 0; i < num_closures; i++) {
    closure ^= closures_array.At(i);
    ASSERT(!closure.IsNull());
    if (closure.raw() == needle.raw()) {
      return i;
    }
  }
  return -1;
}


RawFunction* Class::ClosureFunctionFromIndex(intptr_t idx) const {
  const GrowableObjectArray& closures_array =
      GrowableObjectArray::Handle(closures());
  if ((idx < 0) || (idx >= closures_array.Length())) {
    return Function::null();
  }
  Function& func = Function::Handle();
  func ^= closures_array.At(idx);
  ASSERT(!func.IsNull());
  return func.raw();
}


void Class::set_signature_function(const Function& value) const {
  ASSERT(value.IsClosureFunction() || value.IsSignatureFunction());
  StorePointer(&raw_ptr()->signature_function_, value.raw());
}


void Class::set_state_bits(intptr_t bits) const {
  raw_ptr()->state_bits_ = static_cast<uint16_t>(bits);
}


void Class::set_library(const Library& value) const {
  StorePointer(&raw_ptr()->library_, value.raw());
}


void Class::set_type_parameters(const TypeArguments& value) const {
  StorePointer(&raw_ptr()->type_parameters_, value.raw());
}


intptr_t Class::NumTypeParameters(Isolate* isolate) const {
  if (IsMixinApplication() && !is_mixin_type_applied()) {
    ClassFinalizer::ApplyMixinType(*this);
  }
  if (type_parameters() == TypeArguments::null()) {
    return 0;
  }
  REUSABLE_TYPE_ARGUMENTS_HANDLESCOPE(isolate);
  TypeArguments& type_params = isolate->TypeArgumentsHandle();
  type_params = type_parameters();
  return type_params.Length();
}


intptr_t Class::NumOwnTypeArguments() const {
  // Return cached value if already calculated.
  if (num_own_type_arguments() != kUnknownNumTypeArguments) {
    return num_own_type_arguments();
  }
  Isolate* isolate = Isolate::Current();
  const intptr_t num_type_params = NumTypeParameters();
  if (!FLAG_overlap_type_arguments ||
      (num_type_params == 0) ||
      (super_type() == AbstractType::null()) ||
      (super_type() == isolate->object_store()->object_type())) {
    set_num_own_type_arguments(num_type_params);
    return num_type_params;
  }
  ASSERT(!IsMixinApplication() || is_mixin_type_applied());
  const AbstractType& sup_type = AbstractType::Handle(isolate, super_type());
  const TypeArguments& sup_type_args =
      TypeArguments::Handle(isolate, sup_type.arguments());
  if (sup_type_args.IsNull()) {
    // The super type is raw or the super class is non generic.
    // In either case, overlapping is not possible.
    set_num_own_type_arguments(num_type_params);
    return num_type_params;
  }
  const intptr_t num_sup_type_args = sup_type_args.Length();
  // At this point, the super type may or may not be finalized. In either case,
  // the result of this function must remain the same.
  // The value of num_sup_type_args may increase when the super type is
  // finalized, but the last num_sup_type_args type arguments will not be
  // modified by finalization, only shifted to higher indices in the vector.
  // They may however get wrapped in a BoundedType, which we skip.
  // The super type may not even be resolved yet. This is not necessary, since
  // we only check for matching type parameters, which are resolved by default.
  const TypeArguments& type_params =
      TypeArguments::Handle(isolate, type_parameters());
  // Determine the maximum overlap of a prefix of the vector consisting of the
  // type parameters of this class with a suffix of the vector consisting of the
  // type arguments of the super type of this class.
  // The number of own type arguments of this class is the number of its type
  // parameters minus the number of type arguments in the overlap.
  // Attempt to overlap the whole vector of type parameters; reduce the size
  // of the vector (keeping the first type parameter) until it fits or until
  // its size is zero.
  TypeParameter& type_param = TypeParameter::Handle(isolate);
  AbstractType& sup_type_arg = AbstractType::Handle(isolate);
  for (intptr_t num_overlapping_type_args =
           (num_type_params < num_sup_type_args) ?
               num_type_params : num_sup_type_args;
       num_overlapping_type_args > 0; num_overlapping_type_args--) {
    intptr_t i = 0;
    for (; i < num_overlapping_type_args; i++) {
      type_param ^= type_params.TypeAt(i);
      sup_type_arg = sup_type_args.TypeAt(
          num_sup_type_args - num_overlapping_type_args + i);
      // BoundedType can nest in case the finalized super type has bounded type
      // arguments that overlap multiple times in its own super class chain.
      while (sup_type_arg.IsBoundedType()) {
        sup_type_arg = BoundedType::Cast(sup_type_arg).type();
      }
      if (!type_param.Equals(sup_type_arg)) break;
    }
    if (i == num_overlapping_type_args) {
      // Overlap found.
      set_num_own_type_arguments(num_type_params - num_overlapping_type_args);
      return num_type_params - num_overlapping_type_args;
    }
  }
  // No overlap found.
  set_num_own_type_arguments(num_type_params);
  return num_type_params;
}


intptr_t Class::NumTypeArguments() const {
  // Return cached value if already calculated.
  if (num_type_arguments() != kUnknownNumTypeArguments) {
    return num_type_arguments();
  }
  // To work properly, this call requires the super class of this class to be
  // resolved, which is checked by the type_class() call on the super type.
  // Note that calling type_class() on a MixinAppType fails.
  Isolate* isolate = Isolate::Current();
  Class& cls = Class::Handle(isolate);
  AbstractType& sup_type = AbstractType::Handle(isolate);
  cls = raw();
  intptr_t num_type_args = 0;
  do {
    if (cls.IsSignatureClass()) {
      Function& signature_fun = Function::Handle(isolate);
      signature_fun ^= cls.signature_function();
      if (!signature_fun.is_static() &&
          !signature_fun.HasInstantiatedSignature()) {
        cls = signature_fun.Owner();
      }
    }
    // Calling NumOwnTypeArguments() on a mixin application class will setup the
    // type parameters if not already done.
    num_type_args += cls.NumOwnTypeArguments();
    // Super type of Object class is null.
    if ((cls.super_type() == AbstractType::null()) ||
        (cls.super_type() == isolate->object_store()->object_type())) {
      break;
    }
    sup_type = cls.super_type();
    ClassFinalizer::ResolveTypeClass(cls, sup_type);
    cls = sup_type.type_class();
  } while (true);
  set_num_type_arguments(num_type_args);
  return num_type_args;
}


RawClass* Class::SuperClass() const {
  if (super_type() == AbstractType::null()) {
    return Class::null();
  }
  const AbstractType& sup_type = AbstractType::Handle(super_type());
  return sup_type.type_class();
}


void Class::set_super_type(const AbstractType& value) const {
  ASSERT(value.IsNull() ||
         (value.IsType() && !value.IsDynamicType()) ||
         value.IsMixinAppType());
  StorePointer(&raw_ptr()->super_type_, value.raw());
}


// Return a TypeParameter if the type_name is a type parameter of this class.
// Return null otherwise.
RawTypeParameter* Class::LookupTypeParameter(const String& type_name) const {
  ASSERT(!type_name.IsNull());
  Isolate* isolate = Isolate::Current();
  REUSABLE_TYPE_ARGUMENTS_HANDLESCOPE(isolate);
  REUSABLE_TYPE_PARAMETER_HANDLESCOPE(isolate);
  REUSABLE_STRING_HANDLESCOPE(isolate);
  TypeArguments& type_params = isolate->TypeArgumentsHandle();
  TypeParameter&  type_param = isolate->TypeParameterHandle();
  String& type_param_name = isolate->StringHandle();

  type_params ^= type_parameters();
  if (!type_params.IsNull()) {
    const intptr_t num_type_params = type_params.Length();
    for (intptr_t i = 0; i < num_type_params; i++) {
      type_param ^= type_params.TypeAt(i);
      type_param_name = type_param.name();
      if (type_param_name.Equals(type_name)) {
        return type_param.raw();
      }
    }
  }
  return TypeParameter::null();
}


void Class::CalculateFieldOffsets() const {
  Array& flds = Array::Handle(fields());
  const Class& super = Class::Handle(SuperClass());
  intptr_t offset = 0;
  intptr_t type_args_field_offset = kNoTypeArguments;
  if (super.IsNull()) {
    offset = Instance::NextFieldOffset();
    ASSERT(offset > 0);
  } else {
    ASSERT(super.is_finalized() || super.is_prefinalized());
    type_args_field_offset = super.type_arguments_field_offset();
    offset = super.next_field_offset();
    ASSERT(offset > 0);
    // We should never call CalculateFieldOffsets for native wrapper
    // classes, assert this.
    ASSERT(num_native_fields() == 0);
    set_num_native_fields(super.num_native_fields());
  }
  // If the super class is parameterized, use the same type_arguments field,
  // otherwise, if this class is the first in the super chain to be
  // parameterized, introduce a new type_arguments field.
  if (type_args_field_offset == kNoTypeArguments) {
    const TypeArguments& type_params = TypeArguments::Handle(type_parameters());
    if (!type_params.IsNull()) {
      ASSERT(type_params.Length() > 0);
      // The instance needs a type_arguments field.
      type_args_field_offset = offset;
      offset += kWordSize;
    }
  }
  set_type_arguments_field_offset(type_args_field_offset);
  ASSERT(offset > 0);
  Field& field = Field::Handle();
  intptr_t len = flds.Length();
  for (intptr_t i = 0; i < len; i++) {
    field ^= flds.At(i);
    // Offset is computed only for instance fields.
    if (!field.is_static()) {
      ASSERT(field.Offset() == 0);
      field.SetOffset(offset);
      offset += kWordSize;
    }
  }
  set_instance_size(RoundedAllocationSize(offset));
  set_next_field_offset(offset);
}


RawFunction* Class::GetInvocationDispatcher(const String& target_name,
                                            const Array& args_desc,
                                            RawFunction::Kind kind) const {
  enum {
    kNameIndex = 0,
    kArgsDescIndex,
    kFunctionIndex,
    kEntrySize
  };

  ASSERT(kind == RawFunction::kNoSuchMethodDispatcher ||
         kind == RawFunction::kInvokeFieldDispatcher);
  Function& dispatcher = Function::Handle();
  Array& cache = Array::Handle(invocation_dispatcher_cache());
  ASSERT(!cache.IsNull());
  String& name = String::Handle();
  Array& desc = Array::Handle();
  intptr_t i = 0;
  for (; i < cache.Length(); i += kEntrySize) {
    name ^= cache.At(i + kNameIndex);
    if (name.IsNull()) break;  // Reached last entry.
    if (!name.Equals(target_name)) continue;
    desc ^= cache.At(i + kArgsDescIndex);
    if (desc.raw() != args_desc.raw()) continue;
    dispatcher ^= cache.At(i + kFunctionIndex);
    if (dispatcher.kind() == kind) {
      // Found match.
      ASSERT(dispatcher.IsFunction());
      break;
    }
  }

  if (dispatcher.IsNull()) {
    if (i == cache.Length()) {
      // Allocate new larger cache.
      intptr_t new_len = (cache.Length() == 0)
          ? static_cast<intptr_t>(kEntrySize)
          : cache.Length() * 2;
      cache ^= Array::Grow(cache, new_len);
      set_invocation_dispatcher_cache(cache);
    }
    dispatcher ^= CreateInvocationDispatcher(target_name, args_desc, kind);
    cache.SetAt(i + kNameIndex, target_name);
    cache.SetAt(i + kArgsDescIndex, args_desc);
    cache.SetAt(i + kFunctionIndex, dispatcher);
  }
  return dispatcher.raw();
}


RawFunction* Class::CreateInvocationDispatcher(const String& target_name,
                                               const Array& args_desc,
                                               RawFunction::Kind kind) const {
  Function& invocation = Function::Handle(
      Function::New(String::Handle(Symbols::New(target_name)),
                    kind,
                    false,  // Not static.
                    false,  // Not const.
                    false,  // Not abstract.
                    false,  // Not external.
                    false,  // Not native.
                    *this,
                    0));  // No token position.
  ArgumentsDescriptor desc(args_desc);
  invocation.set_num_fixed_parameters(desc.PositionalCount());
  invocation.SetNumOptionalParameters(desc.NamedCount(),
                                      false);  // Not positional.
  invocation.set_parameter_types(Array::Handle(Array::New(desc.Count(),
                                                          Heap::kOld)));
  invocation.set_parameter_names(Array::Handle(Array::New(desc.Count(),
                                                          Heap::kOld)));
  // Receiver.
  invocation.SetParameterTypeAt(0, Type::Handle(Type::DynamicType()));
  invocation.SetParameterNameAt(0, Symbols::This());
  // Remaining positional parameters.
  intptr_t i = 1;
  for (; i < desc.PositionalCount(); i++) {
    invocation.SetParameterTypeAt(i, Type::Handle(Type::DynamicType()));
    char name[64];
    OS::SNPrint(name, 64, ":p%" Pd, i);
    invocation.SetParameterNameAt(i, String::Handle(Symbols::New(name)));
  }

  // Named parameters.
  for (; i < desc.Count(); i++) {
    invocation.SetParameterTypeAt(i, Type::Handle(Type::DynamicType()));
    intptr_t index = i - desc.PositionalCount();
    invocation.SetParameterNameAt(i, String::Handle(desc.NameAt(index)));
  }
  invocation.set_result_type(Type::Handle(Type::DynamicType()));
  invocation.set_is_visible(false);  // Not visible in stack trace.
  invocation.set_saved_args_desc(args_desc);

  return invocation.raw();
}


RawArray* Class::invocation_dispatcher_cache() const {
  return raw_ptr()->invocation_dispatcher_cache_;
}


void Class::set_invocation_dispatcher_cache(const Array& cache) const {
  StorePointer(&raw_ptr()->invocation_dispatcher_cache_, cache.raw());
}


void Class::Finalize() const {
  ASSERT(!is_finalized());
  // Prefinalized classes have a VM internal representation and no Dart fields.
  // Their instance size  is precomputed and field offsets are known.
  if (!is_prefinalized()) {
    // Compute offsets of instance fields and instance size.
    CalculateFieldOffsets();
  }
  set_is_finalized();
}


// Helper class to handle an array of code weak properties. Implements
// registration and disabling of stored code objects.
class WeakCodeReferences : public ValueObject {
 public:
  explicit WeakCodeReferences(const Array& value) : array_(value) {}
  virtual ~WeakCodeReferences() {}

  void Register(const Code& value) {
    if (!array_.IsNull()) {
      // Try to find and reuse cleared WeakProperty to avoid allocating new one.
      WeakProperty& weak_property = WeakProperty::Handle();
      for (intptr_t i = 0; i < array_.Length(); i++) {
        weak_property ^= array_.At(i);
        if (weak_property.key() == Code::null()) {
          // Empty property found. Reuse it.
          weak_property.set_key(value);
          return;
        }
      }
    }

    const WeakProperty& weak_property = WeakProperty::Handle(
        WeakProperty::New(Heap::kOld));
    weak_property.set_key(value);

    intptr_t length = array_.IsNull() ? 0 : array_.Length();
    const Array& new_array = Array::Handle(
        Array::Grow(array_, length + 1, Heap::kOld));
    new_array.SetAt(length, weak_property);
    UpdateArrayTo(new_array);
  }

  virtual void UpdateArrayTo(const Array& array) = 0;
  virtual void ReportDeoptimization(const Code& code) = 0;
  virtual void ReportSwitchingCode(const Code& code) = 0;

  static bool IsOptimizedCode(const Array& dependent_code, const Code& code) {
    if (!code.is_optimized()) {
      return false;
    }
    WeakProperty& weak_property = WeakProperty::Handle();
    for (intptr_t i = 0; i < dependent_code.Length(); i++) {
      weak_property ^= dependent_code.At(i);
      if (code.raw() == weak_property.key()) {
        return true;
      }
    }
    return false;
  }

  void DisableCode() {
    const Array& code_objects = Array::Handle(array_.raw());
    if (code_objects.IsNull()) {
      return;
    }
    UpdateArrayTo(Object::null_array());
    // Disable all code on stack.
    Code& code = Code::Handle();
    {
      DartFrameIterator iterator;
      StackFrame* frame = iterator.NextFrame();
      while (frame != NULL) {
        code = frame->LookupDartCode();
        if (IsOptimizedCode(code_objects, code)) {
          ReportDeoptimization(code);
          DeoptimizeAt(code, frame->pc());
        }
        frame = iterator.NextFrame();
      }
    }

    // Switch functions that use dependent code to unoptimized code.
    WeakProperty& weak_property = WeakProperty::Handle();
    Function& function = Function::Handle();
    for (intptr_t i = 0; i < code_objects.Length(); i++) {
      weak_property ^= code_objects.At(i);
      code ^= weak_property.key();
      if (code.IsNull()) {
        // Code was garbage collected already.
        continue;
      }

      function ^= code.function();
      // If function uses dependent code switch it to unoptimized.
      if (code.is_optimized() && (function.CurrentCode() == code.raw())) {
        ReportSwitchingCode(code);
        function.SwitchToUnoptimizedCode();
      } else if (function.unoptimized_code() == code.raw()) {
        ReportSwitchingCode(code);
        function.ClearICData();
        // Remove the code object from the function. The next time the
        // function is invoked, it will be compiled again.
        function.ClearCode();
        // Invalidate the old code object so existing references to it
        // (from optimized code) will fail when invoked.
        if (!CodePatcher::IsEntryPatched(code)) {
          CodePatcher::PatchEntry(code);
        }
      } else {
        // Make non-OSR code non-entrant.
        if (code.GetEntryPatchPc() != 0) {
          if (!CodePatcher::IsEntryPatched(code)) {
            ReportSwitchingCode(code);
            CodePatcher::PatchEntry(code);
          }
        }
      }
    }
  }

 private:
  const Array& array_;
  DISALLOW_COPY_AND_ASSIGN(WeakCodeReferences);
};


class CHACodeArray : public WeakCodeReferences {
 public:
  explicit CHACodeArray(const Class& cls)
      : WeakCodeReferences(Array::Handle(cls.cha_codes())), cls_(cls) {
  }

  virtual void UpdateArrayTo(const Array& value) {
    cls_.set_cha_codes(value);
  }

  virtual void ReportDeoptimization(const Code& code) {
    if (FLAG_trace_deoptimization || FLAG_trace_deoptimization_verbose) {
      Function& function = Function::Handle(code.function());
      OS::PrintErr("Deoptimizing %s because CHA optimized (%s).\n",
          function.ToFullyQualifiedCString(),
          cls_.ToCString());
    }
  }

  virtual void ReportSwitchingCode(const Code& code) {
    if (FLAG_trace_deoptimization || FLAG_trace_deoptimization_verbose) {
      Function& function = Function::Handle(code.function());
      OS::PrintErr("Switching %s to unoptimized code because CHA invalid"
                   " (%s)\n",
                   function.ToFullyQualifiedCString(),
                   cls_.ToCString());
    }
  }

 private:
  const Class& cls_;
  DISALLOW_COPY_AND_ASSIGN(CHACodeArray);
};


void Class::RegisterCHACode(const Code& code) {
  ASSERT(code.is_optimized());
  CHACodeArray a(*this);
  a.Register(code);
}


void Class::DisableCHAOptimizedCode() {
  CHACodeArray a(*this);
  a.DisableCode();
}


void Class::set_cha_codes(const Array& cache) const {
  StorePointer(&raw_ptr()->cha_codes_, cache.raw());
}


// Apply the members from the patch class to the original class.
bool Class::ApplyPatch(const Class& patch, Error* error) const {
  ASSERT(error != NULL);
  ASSERT(!is_finalized());
  // Shared handles used during the iteration.
  String& member_name = String::Handle();

  const PatchClass& patch_class =
      PatchClass::Handle(PatchClass::New(*this, patch));

  Array& orig_list = Array::Handle(functions());
  intptr_t orig_len = orig_list.Length();
  Array& patch_list = Array::Handle(patch.functions());
  intptr_t patch_len = patch_list.Length();

  // TODO(iposva): Verify that only patching existing methods and adding only
  // new private methods.
  Function& func = Function::Handle();
  Function& orig_func = Function::Handle();
  // Lookup the original implicit constructor, if any.
  member_name = Name();
  member_name = String::Concat(member_name, Symbols::Dot());
  Function& orig_implicit_ctor = Function::Handle(LookupFunction(member_name));
  if (!orig_implicit_ctor.IsNull() &&
      !orig_implicit_ctor.IsImplicitConstructor()) {
    // Not an implicit constructor, but a user declared one.
    orig_implicit_ctor = Function::null();
  }
  const GrowableObjectArray& new_functions = GrowableObjectArray::Handle(
      GrowableObjectArray::New(orig_len));
  for (intptr_t i = 0; i < orig_len; i++) {
    orig_func ^= orig_list.At(i);
    member_name ^= orig_func.name();
    func = patch.LookupFunction(member_name);
    if (func.IsNull()) {
      // Non-patched function is preserved, all patched functions are added in
      // the loop below.
      // However, an implicitly created constructor should not be preserved if
      // the patch provides a constructor or a factory. Wait for now.
      if (orig_func.raw() != orig_implicit_ctor.raw()) {
        new_functions.Add(orig_func);
      }
    } else if (func.UserVisibleSignature() !=
               orig_func.UserVisibleSignature()) {
      // Compare user visible signatures to ignore different implicit parameters
      // when patching a constructor with a factory.
      *error = LanguageError::NewFormatted(
          *error,  // No previous error.
          Script::Handle(patch.script()),
          func.token_pos(),
          Report::kError,
          Heap::kNew,
          "signature mismatch: '%s'", member_name.ToCString());
      return false;
    }
  }
  for (intptr_t i = 0; i < patch_len; i++) {
    func ^= patch_list.At(i);
    if (func.IsConstructor() || func.IsFactory()) {
      // Do not preserve the original implicit constructor, if any.
      orig_implicit_ctor = Function::null();
    }
    func.set_owner(patch_class);
    new_functions.Add(func);
  }
  if (!orig_implicit_ctor.IsNull()) {
    // Preserve the original implicit constructor.
    new_functions.Add(orig_implicit_ctor);
  }
  Array& new_list = Array::Handle(Array::MakeArray(new_functions));
  SetFunctions(new_list);

  // Merge the two list of fields. Raise an error when duplicates are found or
  // when a public field is being added.
  orig_list = fields();
  orig_len = orig_list.Length();
  patch_list = patch.fields();
  patch_len = patch_list.Length();

  Field& field = Field::Handle();
  Field& orig_field = Field::Handle();
  new_list = Array::New(patch_len + orig_len);
  for (intptr_t i = 0; i < patch_len; i++) {
    field ^= patch_list.At(i);
    field.set_owner(*this);
    member_name = field.name();
    // TODO(iposva): Verify non-public fields only.

    // Verify no duplicate additions.
    orig_field ^= LookupField(member_name);
    if (!orig_field.IsNull()) {
      *error = LanguageError::NewFormatted(
          *error,  // No previous error.
          Script::Handle(patch.script()),
          field.token_pos(),
          Report::kError,
          Heap::kNew,
          "duplicate field: %s", member_name.ToCString());
      return false;
    }
    new_list.SetAt(i, field);
  }
  for (intptr_t i = 0; i < orig_len; i++) {
    field ^= orig_list.At(i);
    new_list.SetAt(patch_len + i, field);
  }
  SetFields(new_list);

  // The functions and fields in the patch class are no longer needed.
  patch.SetFunctions(Object::empty_array());
  patch.SetFields(Object::empty_array());
  return true;
}


static RawString* BuildClosureSource(const Array& formal_params,
                                     const String& expr) {
  const GrowableObjectArray& src_pieces =
      GrowableObjectArray::Handle(GrowableObjectArray::New());
  String& piece = String::Handle();
  src_pieces.Add(Symbols::LParen());
  // Add formal parameters.
  intptr_t num_formals = formal_params.Length();
  for (intptr_t i = 0; i < num_formals; i++) {
    if (i > 0) {
      src_pieces.Add(Symbols::CommaSpace());
    }
    piece ^= formal_params.At(i);
    src_pieces.Add(piece);
  }
  src_pieces.Add(Symbols::RParenArrow());
  src_pieces.Add(expr);
  src_pieces.Add(Symbols::Semicolon());
  return String::ConcatAll(Array::Handle(Array::MakeArray(src_pieces)));
}


static RawFunction* EvaluateHelper(const Class& cls,
                                   const String& expr,
                                   const Array& param_names,
                                   bool is_static) {
  const String& func_src =
      String::Handle(BuildClosureSource(param_names, expr));
  Script& script = Script::Handle();
  script = Script::New(Symbols::Empty(), func_src, RawScript::kSourceTag);
  // In order to tokenize the source, we need to get the key to mangle
  // private names from the library from which the class originates.
  const Library& lib = Library::Handle(cls.library());
  ASSERT(!lib.IsNull());
  const String& lib_key = String::Handle(lib.private_key());
  script.Tokenize(lib_key);

  const Function& func = Function::Handle(
       Function::NewEvalFunction(cls, script, is_static));
  func.set_result_type(Type::Handle(Type::DynamicType()));
  const intptr_t num_implicit_params = is_static ? 0 : 1;
  func.set_num_fixed_parameters(num_implicit_params + param_names.Length());
  func.SetNumOptionalParameters(0, true);
  func.SetIsOptimizable(false);
  return func.raw();
}


RawObject* Class::Evaluate(const String& expr,
                           const Array& param_names,
                           const Array& param_values) const {
  const Function& eval_func =
      Function::Handle(EvaluateHelper(*this, expr, param_names, true));