// 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 "platform/assert.h"
#include "vm/assembler.h"
#include "vm/bigint_operations.h"
#include "vm/bootstrap.h"
#include "vm/code_generator.h"
#include "vm/code_patcher.h"
#include "vm/compiler.h"
#include "vm/compiler_stats.h"
#include "vm/class_finalizer.h"
#include "vm/dart.h"
#include "vm/dart_api_state.h"
#include "vm/dart_entry.h"
#include "vm/debuginfo.h"
#include "vm/double_conversion.h"
#include "vm/exceptions.h"
#include "vm/growable_array.h"
#include "vm/heap.h"
#include "vm/object_store.h"
#include "vm/parser.h"
#include "vm/runtime_entry.h"
#include "vm/scopes.h"
#include "vm/stack_frame.h"
#include "vm/timer.h"
#include "vm/unicode.h"

namespace dart {

DEFINE_FLAG(bool, generate_gdb_symbols, false,
    "Generate symbols of generated dart functions for debugging with GDB");
DECLARE_FLAG(bool, trace_compiler);
DECLARE_FLAG(bool, enable_type_checks);

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 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
RawObject* Object::null_ = reinterpret_cast<RawInstance*>(RAW_NULL);
RawInstance* Object::sentinel_ = reinterpret_cast<RawInstance*>(RAW_NULL);
RawInstance* Object::transition_sentinel_ =
    reinterpret_cast<RawInstance*>(RAW_NULL);
RawClass* Object::class_class_ = reinterpret_cast<RawClass*>(RAW_NULL);
RawClass* Object::null_class_ = reinterpret_cast<RawClass*>(RAW_NULL);
RawClass* Object::dynamic_class_ = reinterpret_cast<RawClass*>(RAW_NULL);
RawClass* Object::void_class_ = reinterpret_cast<RawClass*>(RAW_NULL);
RawClass* Object::unresolved_class_class_ =
    reinterpret_cast<RawClass*>(RAW_NULL);
RawClass* Object::type_class_ = reinterpret_cast<RawClass*>(RAW_NULL);
RawClass* Object::type_parameter_class_ = reinterpret_cast<RawClass*>(RAW_NULL);
RawClass* Object::instantiated_type_class_ =
    reinterpret_cast<RawClass*>(RAW_NULL);
RawClass* Object::abstract_type_arguments_class_ =
    reinterpret_cast<RawClass*>(RAW_NULL);
RawClass* Object::type_arguments_class_ = reinterpret_cast<RawClass*>(RAW_NULL);
RawClass* Object::instantiated_type_arguments_class_ =
    reinterpret_cast<RawClass*>(RAW_NULL);
RawClass* Object::function_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::library_prefix_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::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::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);
#undef RAW_NULL

int Object::GetSingletonClassIndex(const RawClass* raw_class) {
  ASSERT(raw_class->IsHeapObject());
  if (raw_class == class_class()) {
    return kClassClass;
  } else if (raw_class == null_class()) {
    return kNullClass;
  } else if (raw_class == dynamic_class()) {
    return kDynamicClass;
  } else if (raw_class == void_class()) {
    return kVoidClass;
  } else if (raw_class == unresolved_class_class()) {
    return kUnresolvedClassClass;
  } else if (raw_class == type_class()) {
    return kTypeClass;
  } else if (raw_class == type_parameter_class()) {
    return kTypeParameterClass;
  } else if (raw_class == instantiated_type_class()) {
    return kInstantiatedTypeClass;
  } else if (raw_class == abstract_type_arguments_class()) {
    return kAbstractTypeArgumentsClass;
  } else if (raw_class == type_arguments_class()) {
    return kTypeArgumentsClass;
  } else if (raw_class == instantiated_type_arguments_class()) {
    return kInstantiatedTypeArgumentsClass;
  } else if (raw_class == function_class()) {
    return kFunctionClass;
  } else if (raw_class == field_class()) {
    return kFieldClass;
  } else if (raw_class == literal_token_class()) {
    return kLiteralTokenClass;
  } else if (raw_class == token_stream_class()) {
    return kTokenStreamClass;
  } else if (raw_class == script_class()) {
    return kScriptClass;
  } else if (raw_class == library_class()) {
    return kLibraryClass;
  } else if (raw_class == library_prefix_class()) {
    return kLibraryPrefixClass;
  } else if (raw_class == code_class()) {
    return kCodeClass;
  } else if (raw_class == instructions_class()) {
    return kInstructionsClass;
  } else if (raw_class == pc_descriptors_class()) {
    return kPcDescriptorsClass;
  } else if (raw_class == stackmap_class()) {
    return kStackmapClass;
  } else if (raw_class == var_descriptors_class()) {
    return kLocalVarDescriptorsClass;
  } else if (raw_class == exception_handlers_class()) {
    return kExceptionHandlersClass;
  } else if (raw_class == context_class()) {
    return kContextClass;
  } else if (raw_class == context_scope_class()) {
    return kContextScopeClass;
  } else if (raw_class == icdata_class()) {
    return kICDataClass;
  } else if (raw_class == api_error_class()) {
    return kApiErrorClass;
  } else if (raw_class == language_error_class()) {
    return kLanguageErrorClass;
  } else if (raw_class == unhandled_exception_class()) {
    return kUnhandledExceptionClass;
  } else if (raw_class == unwind_error_class()) {
    return kUnwindErrorClass;
  }
  return kInvalidIndex;
}


RawClass* Object::GetSingletonClass(int index) {
  switch (index) {
    case kClassClass: return class_class();
    case kNullClass: return null_class();
    case kDynamicClass: return dynamic_class();
    case kVoidClass: return void_class();
    case kUnresolvedClassClass: return unresolved_class_class();
    case kTypeClass: return type_class();
    case kTypeParameterClass: return type_parameter_class();
    case kInstantiatedTypeClass: return instantiated_type_class();
    case kAbstractTypeArgumentsClass: return abstract_type_arguments_class();
    case kTypeArgumentsClass: return type_arguments_class();
    case kInstantiatedTypeArgumentsClass:
        return instantiated_type_arguments_class();
    case kFunctionClass: return function_class();
    case kFieldClass: return field_class();
    case kLiteralTokenClass: return literal_token_class();
    case kTokenStreamClass: return token_stream_class();
    case kScriptClass: return script_class();
    case kLibraryClass: return library_class();
    case kLibraryPrefixClass: return library_prefix_class();
    case kCodeClass: return code_class();
    case kInstructionsClass: return instructions_class();
    case kPcDescriptorsClass: return pc_descriptors_class();
    case kStackmapClass: return stackmap_class();
    case kLocalVarDescriptorsClass: return var_descriptors_class();
    case kExceptionHandlersClass: return exception_handlers_class();
    case kContextClass: return context_class();
    case kContextScopeClass: return context_scope_class();
    case kICDataClass: return icdata_class();
    case kApiErrorClass: return api_error_class();
    case kLanguageErrorClass: return language_error_class();
    case kUnhandledExceptionClass: return unhandled_exception_class();
    case kUnwindErrorClass: return unwind_error_class();
    default: break;
  }
  UNREACHABLE();
  return reinterpret_cast<RawClass*>(kHeapObjectTag);  // return RAW_NULL.
}


const char* Object::GetSingletonClassName(int index) {
  switch (index) {
    case kClassClass: return "Class";
    case kNullClass: return "Null";
    case kDynamicClass: return "Dynamic";
    case kVoidClass: return "void";
    case kUnresolvedClassClass: return "UnresolvedClass";
    case kTypeClass: return "Type";
    case kTypeParameterClass: return "TypeParameter";
    case kInstantiatedTypeClass: return "InstantiatedType";
    case kAbstractTypeArgumentsClass: return "AbstractTypeArguments";
    case kTypeArgumentsClass: return "TypeArguments";
    case kInstantiatedTypeArgumentsClass: return "InstantiatedTypeArguments";
    case kFunctionClass: return "Function";
    case kFieldClass: return "Field";
    case kTokenStreamClass: return "TokenStream";
    case kScriptClass: return "Script";
    case kLibraryClass: return "Library";
    case kLibraryPrefixClass: return "LibraryPrefix";
    case kCodeClass: return "Code";
    case kInstructionsClass: return "Instructions";
    case kPcDescriptorsClass: return "PcDescriptors";
    case kStackmapClass: return "Stackmap";
    case kLocalVarDescriptorsClass: return "LocalVarDescriptors";
    case kExceptionHandlersClass: return "ExceptionHandlers";
    case kContextClass: return "Context";
    case kContextScopeClass: return "ContextScope";
    case kICDataClass: return "ICData";
    case kApiErrorClass: return "ApiError";
    case kLanguageErrorClass: return "LanguageError";
    case kUnhandledExceptionClass: return "UnhandledException";
    case kUnwindErrorClass: return "UnwindError";
    default: break;
  }
  UNREACHABLE();
  return NULL;
}


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();
  }

  Heap* heap = Isolate::Current()->heap();
  // Allocate and initialize the null instance, except its class_ field.
  // '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);
    InitializeObject(address, Instance::InstanceSize());  // Using 'null_'.
    null_->ptr()->tags_ = 0;
  }

  // Initialize object_store empty array to null_ in order to be able to check
  // if the empty array was allocated (RAW_NULL is not available).
  Isolate::Current()->object_store()->set_empty_array(Array::Handle());

  Class& cls = Class::Handle();

  // Allocate and initialize the class class.
  // At this point, class_class_ is still RAW_NULL, i.e. different from 'null_',
  // since 'null_' is not RAW_NULL anymore. However, class_class_ == null_ must
  // be true before calling Class::New<Class>(), or it will fail.
  class_class_ = Class::Handle().raw();  // Set 'class_class_' to 'null_'.
  cls = Class::New<Class>();
  cls.set_is_finalized();
  class_class_ = cls.raw();
  // Make the class_ field point to itself.
  class_class_->ptr()->class_ = class_class_;

  // Allocate and initialize the null class.
  cls = Class::New<Instance>();
  cls.set_is_finalized();
  null_class_ = cls.raw();

  // Complete initialization of null_ instance, i.e. initialize its class_
  // field.
  null_->ptr()->class_ = null_class_;

  // Allocate and initialize the sentinel values of Null class.
  {
    cls = null_class_;
    Instance& sentinel = Instance::Handle();
    sentinel ^= Object::Allocate(cls, Instance::InstanceSize(), Heap::kOld);
    sentinel_ = sentinel.raw();

    Instance& transition_sentinel = Instance::Handle();
    transition_sentinel ^=
        Object::Allocate(cls, Instance::InstanceSize(), Heap::kOld);
    transition_sentinel_ = transition_sentinel.raw();
  }

  // The interface "Dynamic" is not a VM internal class. It is the type class of
  // the "unknown type". For efficiency, we allocate it in the VM isolate.
  // Therefore, it cannot have a heap allocated name (the name is hard coded,
  // see GetSingletonClassIndex) and its array fields cannot be set to the empty
  // array, but remain null.
  cls = Class::New<Instance>();
  cls.set_is_finalized();
  cls.set_is_interface();
  dynamic_class_ = cls.raw();

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

  cls = Class::New<Instance>();
  cls.set_is_finalized();
  void_class_ = cls.raw();

  cls = Class::New<Type>();
  type_class_ = cls.raw();

  cls = Class::New<TypeParameter>();
  type_parameter_class_ = cls.raw();

  cls = Class::New<InstantiatedType>();
  instantiated_type_class_ = cls.raw();

  cls = Class::New<AbstractTypeArguments>();
  abstract_type_arguments_class_ = cls.raw();

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

  cls = Class::New<InstantiatedTypeArguments>();
  instantiated_type_arguments_class_ = cls.raw();

  cls = Class::New<Function>();
  function_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<LibraryPrefix>();
  library_prefix_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<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<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_);
}


RawClass* Object::CreateAndRegisterInterface(const char* cname,
                                             const Script& script,
                                             const Library& lib) {
  const String& name = String::Handle(String::NewSymbol(cname));
  const Class& cls = Class::Handle(
      Class::NewInterface(name, script, Scanner::kDummyTokenIndex));
  lib.AddClass(cls);
  return cls.raw();
}


void Object::RegisterClass(const Class& cls,
                           const char* cname,
                           const Script& script,
                           const Library& lib) {
  const String& name = String::Handle(String::NewSymbol(cname));
  cls.set_name(name);
  cls.set_script(script);
  lib.AddClass(cls);
}


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

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

  // 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_instance_field_offset(Array::type_arguments_offset());

  Array& empty_array = Array::Handle();
  empty_array = Array::New(0, Heap::kOld);
  object_store->set_empty_array(empty_array);

  // Re-initialize fields of the array class now that the empty array
  // has been created.
  cls.InitEmptyFields();

  // 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_instance_field_offset(
      GrowableObjectArray::type_arguments_offset());

  // Setup the symbol table used within the String class.
  const int kInitialSymbolTableSize = 16;
  array = Array::New(kInitialSymbolTableSize + 1);
  // Last element contains the count of used slots.
  array.SetAt(kInitialSymbolTableSize, Smi::Handle(Smi::New(0)));
  object_store->set_symbol_table(array);

  // canonical_type_arguments_ are NULL terminated.
  array = Array::New(4);
  object_store->set_canonical_type_arguments(array);

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

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

  const GrowableObjectArray& pending_classes =
      GrowableObjectArray::Handle(GrowableObjectArray::New(Heap::kOld));
  object_store->set_pending_classes(pending_classes);

  Context& context = Context::Handle(Context::New(0));
  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.
  const Script& impl_script = Script::Handle(Bootstrap::LoadImplScript());

  cls = Class::New<Smi>();
  object_store->set_smi_class(cls);
  RegisterClass(cls, "Smi", impl_script, core_impl_lib);
  pending_classes.Add(cls, Heap::kOld);

  cls = Class::New<Mint>();
  object_store->set_mint_class(cls);
  RegisterClass(cls, "Mint", impl_script, core_impl_lib);
  pending_classes.Add(cls, Heap::kOld);

  cls = Class::New<Bigint>();
  object_store->set_bigint_class(cls);
  RegisterClass(cls, "Bigint", impl_script, core_impl_lib);
  pending_classes.Add(cls, Heap::kOld);

  cls = Class::New<Double>();
  object_store->set_double_class(cls);
  RegisterClass(cls, "Double", impl_script, core_impl_lib);
  pending_classes.Add(cls, Heap::kOld);

  cls = Class::New<Bool>();
  object_store->set_bool_class(cls);
  RegisterClass(cls, "Bool", impl_script, core_impl_lib);
  pending_classes.Add(cls, Heap::kOld);

  cls = object_store->array_class();  // Was allocated above.
  RegisterClass(cls, "ObjectArray", impl_script, core_impl_lib);
  pending_classes.Add(cls, Heap::kOld);

  cls = object_store->growable_object_array_class();  // Was allocated above.
  RegisterClass(cls, "GrowableObjectArray", impl_script, core_impl_lib);
  pending_classes.Add(cls, Heap::kOld);

  cls = Class::New<ImmutableArray>();
  object_store->set_immutable_array_class(cls);
  cls.set_type_arguments_instance_field_offset(Array::type_arguments_offset());
  ASSERT(object_store->immutable_array_class() != object_store->array_class());
  RegisterClass(cls, "ImmutableArray", impl_script, core_impl_lib);
  pending_classes.Add(cls, Heap::kOld);

  cls = object_store->one_byte_string_class();  // Was allocated above.
  RegisterClass(cls, "OneByteString", impl_script, core_impl_lib);
  pending_classes.Add(cls, Heap::kOld);

  cls = Class::New<TwoByteString>();
  object_store->set_two_byte_string_class(cls);
  RegisterClass(cls, "TwoByteString", impl_script, core_impl_lib);
  pending_classes.Add(cls, Heap::kOld);

  cls = Class::New<FourByteString>();
  object_store->set_four_byte_string_class(cls);
  RegisterClass(cls, "FourByteString", impl_script, core_impl_lib);
  pending_classes.Add(cls, Heap::kOld);

  cls = Class::New<ExternalOneByteString>();
  object_store->set_external_one_byte_string_class(cls);
  RegisterClass(cls, "ExternalOneByteString", impl_script, core_impl_lib);
  pending_classes.Add(cls, Heap::kOld);

  cls = Class::New<ExternalTwoByteString>();
  object_store->set_external_two_byte_string_class(cls);
  RegisterClass(cls, "ExternalTwoByteString", impl_script, core_impl_lib);
  pending_classes.Add(cls, Heap::kOld);

  cls = Class::New<ExternalFourByteString>();
  object_store->set_external_four_byte_string_class(cls);
  RegisterClass(cls, "ExternalFourByteString", impl_script, core_impl_lib);
  pending_classes.Add(cls, Heap::kOld);

  cls = Class::New<Stacktrace>();
  object_store->set_stacktrace_class(cls);
  RegisterClass(cls, "Stacktrace", impl_script, core_impl_lib);
  pending_classes.Add(cls, Heap::kOld);
  // Super type set below, after Object is allocated.

  cls = Class::New<JSRegExp>();
  object_store->set_jsregexp_class(cls);
  RegisterClass(cls, "JSSyntaxRegExp", impl_script, core_impl_lib);
  pending_classes.Add(cls, Heap::kOld);

  // Initialize the base interfaces used by the core VM classes.
  const Script& script = Script::Handle(Bootstrap::LoadScript());

  // Allocate and initialize the Object class and type.
  // The Object and ExternalByteArray classes are the only pre-allocated
  // non-interface classes in the core library.
  cls = Class::New<Instance>();
  object_store->set_object_class(cls);
  cls.set_name(String::Handle(String::NewSymbol("Object")));
  cls.set_script(script);
  core_lib.AddClass(cls);
  pending_classes.Add(cls, Heap::kOld);
  type = Type::NewNonParameterizedType(cls);
  object_store->set_object_type(type);

  cls = Class::New<InternalByteArray>();
  object_store->set_internal_byte_array_class(cls);
  String& public_class_name = String::Handle();
  public_class_name = String::New("_InternalByteArray");
  cls.set_name(String::Handle(core_lib.PrivateName(public_class_name)));
  cls.set_script(script);
  core_lib.AddClass(cls);

  cls = Class::New<ExternalByteArray>();
  object_store->set_external_byte_array_class(cls);
  public_class_name = String::New("_ExternalByteArray");
  cls.set_name(String::Handle(core_lib.PrivateName(public_class_name)));
  cls.set_script(script);
  core_lib.AddClass(cls);

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

  cls = CreateAndRegisterInterface("Function", script, core_lib);
  pending_classes.Add(cls, Heap::kOld);
  type = Type::NewNonParameterizedType(cls);
  object_store->set_function_interface(type);

  cls = CreateAndRegisterInterface("num", script, core_lib);
  pending_classes.Add(cls, Heap::kOld);
  type = Type::NewNonParameterizedType(cls);
  object_store->set_number_interface(type);

  cls = CreateAndRegisterInterface("int", script, core_lib);
  pending_classes.Add(cls, Heap::kOld);
  type = Type::NewNonParameterizedType(cls);
  object_store->set_int_interface(type);

  cls = CreateAndRegisterInterface("double", script, core_lib);
  pending_classes.Add(cls, Heap::kOld);
  type = Type::NewNonParameterizedType(cls);
  object_store->set_double_interface(type);

  cls = CreateAndRegisterInterface("String", script, core_lib);
  pending_classes.Add(cls, Heap::kOld);
  type = Type::NewNonParameterizedType(cls);
  object_store->set_string_interface(type);

  cls = CreateAndRegisterInterface("bool", script, core_lib);
  pending_classes.Add(cls, Heap::kOld);
  type = Type::NewNonParameterizedType(cls);
  object_store->set_bool_interface(type);

  cls = CreateAndRegisterInterface("List", script, core_lib);
  pending_classes.Add(cls, Heap::kOld);
  type = Type::NewNonParameterizedType(cls);
  object_store->set_list_interface(type);

  cls = CreateAndRegisterInterface("ByteArray", script, core_lib);
  pending_classes.Add(cls, Heap::kOld);
  type = Type::NewNonParameterizedType(cls);
  object_store->set_byte_array_interface(type);

  // The classes 'Null' and 'void' are not registered in the class dictionary,
  // because their names are reserved keywords. Their names are not heap
  // allocated, because the classes reside in the VM isolate.
  // The corresponding types are stored in the object store.
  cls = null_class_;
  type = Type::NewNonParameterizedType(cls);
  object_store->set_null_type(type);

  cls = void_class_;
  type = Type::NewNonParameterizedType(cls);
  object_store->set_void_type(type);

  // The class 'Dynamic' is registered in the class dictionary because its name
  // is a built-in identifier, rather than a reserved keyword. Its name is not
  // heap allocated, because the class resides in the VM isolate.
  // The corresponding type, the "unknown type", is stored in the object store.
  cls = dynamic_class_;
  type = Type::NewNonParameterizedType(cls);
  object_store->set_dynamic_type(type);
  core_lib.AddClass(cls);

  // Allocate pre-initialized values.
  Bool& bool_value = Bool::Handle();
  bool_value = Bool::New(true);
  object_store->set_true_value(bool_value);
  bool_value = Bool::New(false);
  object_store->set_false_value(bool_value);

  // 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());

  // Finish the initialization by compiling the bootstrap scripts containing the
  // base interfaces and the implementation of the internal classes.
  Error& error = Error::Handle();
  error = Bootstrap::Compile(core_lib, script);
  if (!error.IsNull()) {
    return error.raw();
  }
  error = Bootstrap::Compile(core_impl_lib, impl_script);
  if (!error.IsNull()) {
    return error.raw();
  }
  const Script& isolate_script = Script::Handle(Bootstrap::LoadIsolateScript());
  Library::InitIsolateLibrary(isolate);
  Library& isolate_lib = Library::Handle(Library::IsolateLibrary());
  ASSERT(!isolate_lib.IsNull());
  error = Bootstrap::Compile(isolate_lib, isolate_script);
  if (!error.IsNull()) {
    return error.raw();
  }
  const Script& mirrors_script = Script::Handle(Bootstrap::LoadMirrorsScript());
  Library::InitMirrorsLibrary(isolate);
  Library& mirrors_lib = Library::Handle(Library::MirrorsLibrary());
  ASSERT(!mirrors_lib.IsNull());
  error = Bootstrap::Compile(mirrors_lib, mirrors_script);
  if (!error.IsNull()) {
    return error.raw();
  }
  Bootstrap::SetupNativeResolver();

  // Remove the Object superclass cycle by setting the super type to null (not
  // to the type of null).
  cls = object_store->object_class();
  cls.set_super_type(Type::Handle());

  ClassFinalizer::VerifyBootstrapClasses();
  return Error::null();
}


void Object::InitFromSnapshot(Isolate* isolate) {
  TIMERSCOPE(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<Array>();
  object_store->set_array_class(cls);

  Array& empty_array = Array::Handle();
  empty_array = Array::New(0);
  object_store->set_empty_array(empty_array);

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

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

  cls = Class::New<InternalByteArray>();
  object_store->set_internal_byte_array_class(cls);

  cls = Class::New<ExternalByteArray>();
  object_store->set_external_byte_array_class(cls);

  cls = Class::New<Instance>();
  object_store->set_object_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::New<OneByteString>();
  object_store->set_one_byte_string_class(cls);

  cls = Class::New<TwoByteString>();
  object_store->set_two_byte_string_class(cls);

  cls = Class::New<FourByteString>();
  object_store->set_four_byte_string_class(cls);

  cls = Class::New<ExternalOneByteString>();
  object_store->set_external_one_byte_string_class(cls);

  cls = Class::New<ExternalTwoByteString>();
  object_store->set_external_two_byte_string_class(cls);

  cls = Class::New<ExternalFourByteString>();
  object_store->set_external_four_byte_string_class(cls);

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

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

  cls = Class::New<JSRegExp>();
  object_store->set_jsregexp_class(cls);

  // Allocate pre-initialized values.
  Bool& bool_value = Bool::Handle();
  bool_value = Bool::New(true);
  object_store->set_true_value(bool_value);
  bool_value = Bool::New(false);
  object_store->set_false_value(bool_value);
}


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


void Object::InitializeObject(uword address, 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;
  }
}


RawObject* Object::Allocate(const Class& cls,
                            intptr_t size,
                            Heap::Space space) {
  ASSERT(Utils::IsAligned(size, kObjectAlignment));
  Isolate* isolate = Isolate::Current();
  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(exception);
    UNREACHABLE();
  }
  NoGCScope no_gc;
  InitializeObject(address, size);
  RawObject* raw_obj = reinterpret_cast<RawObject*>(address + kHeapObjectTag);
  raw_obj->ptr()->class_ = cls.raw();
  uword tags = 0;
  tags = RawObject::SizeTag::update(size, tags);
  raw_obj->ptr()->tags_ = tags;
  return raw_obj;
}


RawString* Class::Name() const {
  if (raw_ptr()->name_ != String::null()) {
    return raw_ptr()->name_;
  }
  ASSERT(class_class() != Class::null());  // class_class_ should be set up.
  intptr_t index = GetSingletonClassIndex(raw());
  return String::NewSymbol(GetSingletonClassName(index));
}


RawType* Class::SignatureType() const {
  // Return the first canonical signature type if already computed.
  const Array& signature_types = Array::Handle(canonical_types());
  if (signature_types.Length() > 0) {
    Type& signature_type = Type::Handle();
    signature_type ^= signature_types.At(0);
    if (!signature_type.IsNull()) {
      return signature_type.raw();
    }
  }
  ASSERT(IsSignatureClass());
  // 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_index()));

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


template <class FakeObject>
RawClass* Class::New() {
  Class& class_class = Class::Handle(Object::class_class());
  Class& result = Class::Handle();
  {
    RawObject* raw = Object::Allocate(class_class,
                                      Class::InstanceSize(),
                                      Heap::kOld);
    NoGCScope no_gc;
    if (class_class.IsNull()) {
      // Allocating class_class, avoid using uninitialized class vtable.
      result.raw_ = raw;
    } else {
      result ^= raw;
    }
  }
  FakeObject fake;
  result.set_handle_vtable(fake.vtable());
  result.set_instance_size(FakeObject::InstanceSize());
  result.set_next_field_offset(FakeObject::InstanceSize());
  result.set_instance_kind(FakeObject::kInstanceKind);
  result.raw_ptr()->is_const_ = false;
  result.raw_ptr()->is_interface_ = false;
  // VM backed classes are almost ready: run checks and resolve class
  // references, but do not recompute size.
  result.raw_ptr()->class_state_ = RawClass::kPreFinalized;
  result.raw_ptr()->type_arguments_instance_field_offset_ = kNoTypeArguments;
  result.raw_ptr()->num_native_fields_ = 0;
  result.raw_ptr()->token_index_ = Scanner::kDummyTokenIndex;
  result.InitEmptyFields();
  return result.raw();
}


// Initialize class fields of type Array with empty array.
void Class::InitEmptyFields() {
  const Array& empty_array = Array::Handle(Array::Empty());
  if (empty_array.IsNull()) {
    // The empty array has not been initialized yet.
    return;
  }
  StorePointer(&raw_ptr()->interfaces_, empty_array.raw());
  // TODO(srdjan): Make functions_cache growable and start with a smaller size.
  Array& fcache =
      Array::Handle(Array::New(FunctionsCache::kNumEntries * 32, Heap::kOld));
  StorePointer(&raw_ptr()->functions_cache_, fcache.raw());
  StorePointer(&raw_ptr()->constants_, empty_array.raw());
  StorePointer(&raw_ptr()->canonical_types_, empty_array.raw());
  StorePointer(&raw_ptr()->functions_, empty_array.raw());
  StorePointer(&raw_ptr()->fields_, empty_array.raw());
}

void Class::SetFunctions(const Array& value) const {
  ASSERT(!value.IsNull());
  // Bind all the functions in the array to this class.
  Function& func = Function::Handle();
  intptr_t len = value.Length();
  for (intptr_t i = 0; i < len; i++) {
    func ^= value.At(i);
    func.set_owner(*this);
  }
  StorePointer(&raw_ptr()->functions_, value.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());
  closures.Add(function);
}


// Lookup the innermost closure function that contains token at token_index.
RawFunction* Class::LookupClosureFunction(intptr_t token_index) 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_index = -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_index() <= token_index) &&
        (token_index < closure.end_token_index()) &&
        (best_fit_token_index < closure.token_index())) {
      best_fit_index = i;
      best_fit_token_index = closure.token_index();
    }
  }
  closure = Function::null();
  if (best_fit_index >= 0) {
    closure ^= closures.At(best_fit_index);
  }
  return closure.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_class_state(int8_t state) const {
  ASSERT(state == RawClass::kAllocated ||
         state == RawClass::kPreFinalized ||
         state == RawClass::kFinalized);
  raw_ptr()->class_state_ = state;
}


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());
}


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


intptr_t Class::NumTypeParameters() const {
  const TypeArguments& type_params = TypeArguments::Handle(type_parameters());
  if (type_params.IsNull()) {
    return 0;
  } else {
    return type_params.Length();
  }
}


intptr_t Class::NumTypeArguments() const {
  // To work properly, this call requires the super class of this class to be
  // resolved, which is checked by the SuperClass() call.
  Class& cls = Class::Handle(raw());
  if (IsSignatureClass()) {
    const Function& signature_fun = Function::Handle(signature_function());
    if (!signature_fun.is_static() &&
        !signature_fun.HasInstantiatedSignature()) {
      cls = signature_fun.owner();
    }
  }
  intptr_t num_type_args = NumTypeParameters();
  const Class& superclass = Class::Handle(cls.SuperClass());
  // Object is its own super class during bootstrap.
  if (!superclass.IsNull() && (superclass.raw() != raw())) {
    num_type_args += superclass.NumTypeArguments();
  }
  return num_type_args;
}


bool Class::HasTypeArguments() const {
  if (!IsSignatureClass() && (is_finalized() || is_prefinalized())) {
    // More efficient than calling NumTypeArguments().
    return type_arguments_instance_field_offset() != kNoTypeArguments;
  } else {
    // No need to check NumTypeArguments() if class has type parameters.
    return (NumTypeParameters() > 0) || (NumTypeArguments() > 0);
  }
}


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


void Class::set_super_type(const Type& value) const {
  StorePointer(&raw_ptr()->super_type_, value.raw());
}


bool Class::HasFactoryClass() const {
  const Object& factory_class = Object::Handle(raw_ptr()->factory_class_);
  return !factory_class.IsNull();
}


bool Class::HasResolvedFactoryClass() const {
  ASSERT(HasFactoryClass());
  const Object& factory_class = Object::Handle(raw_ptr()->factory_class_);
  return factory_class.IsClass();
}


RawClass* Class::FactoryClass() const {
  ASSERT(HasResolvedFactoryClass());
  Class& type_class = Class::Handle();
  type_class ^= raw_ptr()->factory_class_;
  return type_class.raw();
}


RawUnresolvedClass* Class::UnresolvedFactoryClass() const {
  ASSERT(!HasResolvedFactoryClass());
  UnresolvedClass& unresolved_factory_class = UnresolvedClass::Handle();
  unresolved_factory_class ^= raw_ptr()->factory_class_;
  return unresolved_factory_class.raw();
}


void Class::set_factory_class(const Object& value) const {
  StorePointer(&raw_ptr()->factory_class_, 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,
                                             intptr_t token_index) const {
  ASSERT(!type_name.IsNull());
  const TypeArguments& type_params = TypeArguments::Handle(type_parameters());
  if (!type_params.IsNull()) {
    intptr_t num_type_params = type_params.Length();
    TypeParameter& type_param = TypeParameter::Handle();
    String& type_param_name = String::Handle();
    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)) {
        intptr_t index = type_param.Index();
        // Create a non-finalized new TypeParameter with the given token_index.
        if (type_param.IsFinalized()) {
          // The index was adjusted during finalization. Revert.
          index -= NumTypeArguments() - num_type_params;
        } else {
          ASSERT(type_param.Index() == i);
        }
        return TypeParameter::New(*this, index, type_name, token_index);
      }
    }
  }
  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 = sizeof(RawObject);
  } else {
    type_args_field_offset = super.type_arguments_instance_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.
  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_instance_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);
}


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();
}


void Class::SetFields(const Array& value) const {
  ASSERT(!value.IsNull());
  Field& field = Field::Handle();
  intptr_t len = value.Length();
  for (intptr_t i = 0; i < len; i++) {
    field ^= value.At(i);
    field.set_owner(*this);
    // Only static const fields may contain the Object::sentinel value.
    ASSERT(!(field.is_static() && field.is_final()) ||
           (field.value() == Object::sentinel()));
  }
  // The value of static fields is already initialized to null.
  StorePointer(&raw_ptr()->fields_, value.raw());
}


template <class FakeInstance>
RawClass* Class::New(const String& name,
                     const Script& script,
                     intptr_t token_index) {
  ASSERT(token_index >= 0);
  Class& class_class = Class::Handle(Object::class_class());
  Class& result = Class::Handle();
  {
    RawObject* raw = Object::Allocate(class_class,
                                      Class::InstanceSize(),
                                      Heap::kOld);
    NoGCScope no_gc;
    result ^= raw;
  }
  FakeInstance fake;
  ASSERT(fake.IsInstance());
  result.set_handle_vtable(fake.vtable());
  result.set_instance_size(FakeInstance::InstanceSize());
  result.set_next_field_offset(FakeInstance::InstanceSize());
  result.set_instance_kind(FakeInstance::kInstanceKind);
  result.set_name(name);
  result.set_script(script);
  result.set_token_index(token_index);
  result.raw_ptr()->is_const_ = false;
  result.raw_ptr()->is_interface_ = false;
  result.raw_ptr()->class_state_ = RawClass::kAllocated;
  result.raw_ptr()->type_arguments_instance_field_offset_ = kNoTypeArguments;
  result.raw_ptr()->num_native_fields_ = 0;
  result.InitEmptyFields();
  return result.raw();
}


RawClass* Class::New(const String& name,
                     const Script& script,
                     intptr_t token_index) {
  Class& result = Class::Handle(New<Instance>(name, script, token_index));
  return result.raw();
}


RawClass* Class::NewInterface(const String& name,
                              const Script& script,
                              intptr_t token_index) {
  Class& result = Class::Handle(New<Instance>(name, script, token_index));
  result.set_is_interface();
  return result.raw();
}


RawClass* Class::NewSignatureClass(const String& name,
                                   const Function& signature_function,
                                   const Script& script) {
  ASSERT(!signature_function.IsNull());
  const Class& owner_class = Class::Handle(signature_function.owner());
  ASSERT(!owner_class.IsNull());
  TypeArguments& type_parameters = TypeArguments::Handle();
  TypeArguments& type_parameter_bounds = TypeArguments::Handle();
  // 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.
  if (!signature_function.is_static()) {
    if ((owner_class.NumTypeParameters() > 0) &&
        !signature_function.HasInstantiatedSignature()) {
      type_parameters = owner_class.type_parameters();
      type_parameter_bounds = owner_class.type_parameter_bounds();
    }
  }
  const intptr_t token_index = signature_function.token_index();
  Class& result = Class::Handle(New<Closure>(name, script, token_index));
  const Type& super_type = Type::Handle(Type::ObjectType());
  ASSERT(!super_type.IsNull());
  result.set_super_type(super_type);
  result.set_signature_function(signature_function);
  result.set_type_parameters(type_parameters);
  result.set_type_parameter_bounds(type_parameter_bounds);
  result.SetFields(Array::Handle(Array::Empty()));
  result.SetFunctions(Array::Handle(Array::Empty()));
  // Implements interface "Function".
  const Type& function_interface = Type::Handle(Type::FunctionInterface());
  const Array& interfaces = Array::Handle(Array::New(1, Heap::kOld));
  interfaces.SetAt(0, function_interface);
  result.set_interfaces(interfaces);
  // Unless the signature function already has a signature class, create a
  // canonical signature class by having the signature function point back to
  // the signature class.
  if (signature_function.signature_class() == Object::null()) {
    signature_function.set_signature_class(result);
  }
  result.set_is_finalized();
  // Instances of a signature class can only be closures.
  ASSERT(result.instance_size() == Closure::InstanceSize());
  // Cache the signature type as the first canonicalized type in result.
  const Type& signature_type = Type::Handle(result.SignatureType());
  ASSERT(!signature_type.IsFinalized());
  const Array& new_canonical_types = Array::Handle(Array::New(1, Heap::kOld));
  new_canonical_types.SetAt(0, signature_type);
  result.set_canonical_types(new_canonical_types);
  return result.raw();
}


RawClass* Class::GetClass(ObjectKind kind) {
  ObjectStore* object_store = Isolate::Current()->object_store();
  switch (kind) {
    case kSmi:
      ASSERT(object_store->smi_class() != Class::null());
      return object_store->smi_class();
    case kMint:
      ASSERT(object_store->mint_class() != Class::null());
      return object_store->mint_class();
    case kBigint:
      ASSERT(object_store->bigint_class() != Class::null());
      return object_store->bigint_class();
    case kDouble:
      ASSERT(object_store->double_class() != Class::null());
      return object_store->double_class();
    case kOneByteString:
      ASSERT(object_store->one_byte_string_class() != Class::null());
      return object_store->one_byte_string_class();
    case kTwoByteString:
      ASSERT(object_store->two_byte_string_class() != Class::null());
      return object_store->two_byte_string_class();
    case kFourByteString:
      ASSERT(object_store->four_byte_string_class() != Class::null());
      return object_store->four_byte_string_class();
    case kExternalOneByteString:
      ASSERT(object_store->external_one_byte_string_class() != Class::null());
      return object_store->external_one_byte_string_class();
    case kExternalTwoByteString:
      ASSERT(object_store->external_two_byte_string_class() != Class::null());
      return object_store->external_two_byte_string_class();
    case kExternalFourByteString:
      ASSERT(object_store->external_four_byte_string_class() != Class::null());
      return object_store->external_four_byte_string_class();
    case kBool:
      ASSERT(object_store->bool_class() != Class::null());
      return object_store->bool_class();
    case kArray:
      ASSERT(object_store->array_class() != Class::null());
      return object_store->array_class();
    case kImmutableArray:
      ASSERT(object_store->immutable_array_class() != Class::null());
      return object_store->immutable_array_class();
    case kGrowableObjectArray:
      ASSERT(object_store->growable_object_array_class() != Class::null());
      return object_store->growable_object_array_class();
    case kInternalByteArray:
      ASSERT(object_store->internal_byte_array_class() != Class::null());
      return object_store->internal_byte_array_class();
    case kExternalByteArray:
      ASSERT(object_store->external_byte_array_class() != Class::null());
      return object_store->external_byte_array_class();
    case kStacktrace:
      ASSERT(object_store->stacktrace_class() != Class::null());
      return object_store->stacktrace_class();
    case kJSRegExp:
      ASSERT(object_store->jsregexp_class() != Class::null());
      return object_store->jsregexp_class();
    case kClosure:
      return Class::New<Closure>();
    case kInstance:
      return Class::New<Instance>();
    default:
      UNREACHABLE();
  }
  return Class::null();
}


RawClass* Class::NewNativeWrapper(Library* library,
                                  const String& name,
                                  int field_count) {
  Class& cls = Class::Handle(library->LookupClass(name));
  if (cls.IsNull()) {
    cls = New<Instance>(name, Script::Handle(), Scanner::kDummyTokenIndex);
    cls.SetFields(Array::Handle(Array::Empty()));
    cls.SetFunctions(Array::Handle(Array::Empty()));
    // Set super class to Object.
    cls.set_super_type(Type::Handle(Type::ObjectType()));
    // Compute instance size.
    intptr_t instance_size = (field_count * kWordSize) + sizeof(RawObject);
    cls.set_instance_size(RoundedAllocationSize(instance_size));
    cls.set_next_field_offset(instance_size);
    cls.set_num_native_fields(field_count);
    cls.set_is_finalized();
    library->AddClass(cls);
    return cls.raw();
  } else {
    return Class::null();
  }
}


void Class::set_name(const String& value) const {
  ASSERT(value.IsSymbol());
  StorePointer(&raw_ptr()->name_, value.raw());
}


void Class::set_script(const Script& value) const {
  StorePointer(&raw_ptr()->script_, value.raw());
}


void Class::set_token_index(intptr_t token_index) const {
  ASSERT(token_index >= 0);
  raw_ptr()->token_index_ = token_index;
}


void Class::set_is_interface() const {
  raw_ptr()->is_interface_ = true;
}


void Class::set_is_const() const {
  raw_ptr()->is_const_ = true;
}


void Class::set_is_finalized() const {
  ASSERT(!is_finalized());
  set_class_state(RawClass::kFinalized);
}


void Class::set_interfaces(const Array& value) const {
  // Verification and resolving of interfaces occurs in finalizer.
  ASSERT(!value.IsNull());
  StorePointer(&raw_ptr()->interfaces_, value.raw());
}


void Class::set_functions_cache(const Array& value) const {
  ASSERT(!value.IsNull());
  StorePointer(&raw_ptr()->functions_cache_, value.raw());
}


RawArray* Class::constants() const {
  return raw_ptr()->constants_;
}

void Class::set_constants(const Array& value) const {
  ASSERT(!value.IsNull());
  StorePointer(&raw_ptr()->constants_, value.raw());
}


RawArray* Class::canonical_types() const {
  return raw_ptr()->canonical_types_;
}

void Class::set_canonical_types(const Array& value) const {
  ASSERT(!value.IsNull());
  StorePointer(&raw_ptr()->canonical_types_, value.raw());
}


void Class::set_allocation_stub(const Code& value) const {
  ASSERT(!value.IsNull());
  ASSERT(raw_ptr()->allocation_stub_ == Code::null());
  StorePointer(&raw_ptr()->allocation_stub_, value.raw());
}


bool Class::IsObjectClass() const {
  return raw() == Type::Handle(Type::ObjectType()).type_class();
}


bool Class::IsCanonicalSignatureClass() const {
  const Function& function = Function::Handle(signature_function());
  return (!function.IsNull() && (function.signature_class() == raw()));
}


// Checks if the type S is a subtype of type T.
// Type S is specified by this class parameterized with 'type_arguments', and
// type T by class 'other' parameterized with 'other_type_arguments'.
// This class and class 'other' do not need to be finalized, however, they must
// be resolved as well as their interfaces.
bool Class::IsSubtypeOf(
    const AbstractTypeArguments& type_arguments,
    const Class& other,
    const AbstractTypeArguments& other_type_arguments,
    Error* malformed_error) const {
  // Check for DynamicType.
  // The DynamicType on the lefthand side is replaced by the bottom type, which
  // is more specific than any type.
  // Any type is more specific than the DynamicType on the righthand side.
  if (IsDynamicClass() || other.IsDynamicClass()) {
    return true;
  }
  // Check for reflexivity.
  if (raw() == other.raw()) {
    const intptr_t len = NumTypeArguments();
    if (len == 0) {
      return true;
    }
    // Since we do not truncate the type argument vector of a subclass (see
    // below), we only check a prefix of the proper length.
    // Check for covariance.
    if (type_arguments.IsNull() ||
        other_type_arguments.IsNull() ||
        type_arguments.IsRawInstantiatedRaw(len) ||
        other_type_arguments.IsRawInstantiatedRaw(len)) {
      return true;
    }
    return type_arguments.IsSubtypeOf(other_type_arguments,
                                      len,
                                      malformed_error);
  }
  // Check for two function types.
  if (IsSignatureClass() && other.IsSignatureClass()) {
    const Function& fun = Function::Handle(signature_function());
    const Function& other_fun = Function::Handle(other.signature_function());
    return fun.IsSubtypeOf(type_arguments,
                           other_fun,
                           other_type_arguments,
                           malformed_error);
  }
  // Check for 'direct super type' in the case of an interface
  // (i.e. other.is_interface()) or implicit interface (i.e.
  // !other.is_interface()) and check for transitivity at the same time.
  Array& interfaces = Array::Handle(this->interfaces());
  AbstractType& interface = AbstractType::Handle();
  Class& interface_class = Class::Handle();
  AbstractTypeArguments& interface_args = AbstractTypeArguments::Handle();
  for (intptr_t i = 0; i < interfaces.Length(); i++) {
    interface ^= interfaces.At(i);
    interface_class = interface.type_class();
    interface_args = interface.arguments();
    if (!interface_args.IsNull() && !interface_args.IsInstantiated()) {
      // This type class implements an interface that is parameterized with
      // generic type(s), e.g. it implements List<T>.
      // The uninstantiated type T must be instantiated using the type
      // parameters of this type before performing the type test.
      // The type arguments of this type that are referred to by the type
      // parameters of the interface are at the end of the type vector,
      // after the type arguments of the super type of this type.
      // The index of the type parameters is adjusted upon finalization.
      ASSERT(interface.IsFinalized());
      interface_args = interface_args.InstantiateFrom(type_arguments);
      // In checked mode, verify that the instantiated interface type
      // arguments are within the bounds specified by the interface class.
      // Note that the additional bounds check in checked mode may lead to a
      // dynamic type error, but it will never change the result of the type
      // check from true in production mode to false in checked mode.
      if (FLAG_enable_type_checks && !interface_args.IsNull()) {
        // Pass type_arguments as bounds instantiator.
        if (!interface_args.IsWithinBoundsOf(interface_class,
                                             type_arguments,
                                             malformed_error)) {
          continue;
        }
      }
    }
    if (interface_class.IsSubtypeOf(interface_args,
                                    other,
                                    other_type_arguments,
                                    malformed_error)) {
      return true;
    }
  }
  // Check the interface case.
  if (is_interface()) {
    // We already checked the case where 'other' is an interface. Now, 'this',
    // an interface, cannot be more specific than a class, except class Object,
    // because although Object is not considered an interface by the vm, it is
    // one. In other words, all classes implementing this interface also extend
    // class Object. An interface is also more specific than the DynamicType.
    return (other.IsDynamicClass() || other.IsObjectClass());
  }
  const Class& super_class = Class::Handle(SuperClass());
  if (super_class.IsNull()) {
    return false;
  }
  // Instead of truncating the type argument vector to the length of the super
  // type argument vector, we make sure that the code works with a vector that
  // is longer than necessary.
  return super_class.IsSubtypeOf(type_arguments,
                                 other,
                                 other_type_arguments,
                                 malformed_error);
}


bool Class::IsTopLevel() const {
  return String::Handle(Name()).Equals("::");
}


RawFunction* Class::LookupDynamicFunction(const String& name) const {
  Function& function = Function::Handle(LookupFunction(name));
  if (function.IsNull() || !function.IsDynamicFunction()) {
    return Function::null();
  }
  return function.raw();
}


RawFunction* Class::LookupStaticFunction(const String& name) const {
  Function& function = Function::Handle(LookupFunction(name));
  if (function.IsNull() || !function.IsStaticFunction()) {
    return Function::null();
  }
  return function.raw();
}


RawFunction* Class::LookupConstructor(const String& name) const {
  Function& function = Function::Handle(LookupFunction(name));
  if (function.IsNull() || !function.IsConstructor()) {
    return Function::null();
  }
  ASSERT(!function.is_static());
  return function.raw();
}


RawFunction* Class::LookupFactory(const String& name) const {
  Function& function = Function::Handle(LookupFunction(name));
  if (function.IsNull() || !function.IsFactory()) {
    return Function::null();
  }
  ASSERT(function.is_static());
  return function.raw();
}


static bool MatchesAccessorName(const String& name,
                                const char* prefix,
                                intptr_t prefix_length,
                                const String& accessor_name) {
  intptr_t name_len = name.Length();
  intptr_t accessor_name_len = accessor_name.Length();

  if (name_len != (accessor_name_len + prefix_length)) {
    return false;
  }
  for (intptr_t i = 0; i < prefix_length; i++) {
    if (name.CharAt(i) != prefix[i]) {
      return false;
    }
  }
  for (intptr_t i = 0, j = prefix_length; i < accessor_name_len; i++, j++) {
    if (name.CharAt(j) != accessor_name.CharAt(i)) {
      return false;
    }
  }
  return true;
}


static bool MatchesPrivateName(const String& name, const String& private_name) {
  intptr_t name_len = name.Length();
  intptr_t private_len = private_name.Length();
  // The private_name must at least have room for the separator and one key
  // character.
  if ((name_len < (private_len + 2)) || (name_len == 0) || (private_len == 0)) {
    return false;
  }

  // Check for the private key separator.
  if (name.CharAt(private_len) != Scanner::kPrivateKeySeparator) {
    return false;
  }

  for (intptr_t i = 0; i < private_len; i++) {
    if (name.CharAt(i) != private_name.CharAt(i)) {
      return false;
    }
  }
  return true;
}


RawFunction* Class::LookupFunction(const String& name) const {
  Isolate* isolate = Isolate::Current();
  Array& funcs = Array::Handle(isolate, functions());
  Function& function = Function::Handle(isolate, Function::null());
  String& function_name = String::Handle(isolate, String::null());
  intptr_t len = funcs.Length();
  for (intptr_t i = 0; i < len; i++) {
    function ^= funcs.At(i);
    function_name ^= function.name();
    if (function_name.Equals(name) || MatchesPrivateName(function_name, name)) {
      return function.raw();
    }
  }

  // No function found.
  return Function::null();
}


RawFunction* Class::LookupGetterFunction(const String& name) const {
  return LookupAccessorFunction(kGetterPrefix, kGetterPrefixLength, name);
}


RawFunction* Class::LookupSetterFunction(const String& name) const {
  return LookupAccessorFunction(kSetterPrefix, kSetterPrefixLength, name);
}


RawFunction* Class::LookupAccessorFunction(const char* prefix,
                                           intptr_t prefix_length,
                                           const String& name) const {
  Isolate* isolate = Isolate::Current();
  Array& funcs = Array::Handle(isolate, functions());
  Function& function = Function::Handle(isolate, Function::null());
  String& function_name = String::Handle(isolate, String::null());
  intptr_t len = funcs.Length();
  for (intptr_t i = 0; i < len; i++) {
    function ^= funcs.At(i);
    function_name ^= function.name();
    if (MatchesAccessorName(function_name, prefix, prefix_length, name)) {
      return function.raw();
    }
  }

  // No function found.
  return Function::null();
}


RawFunction* Class::LookupFunctionAtToken(intptr_t token_index) const {
  // TODO(hausner): we can shortcut the negative case if we knew the
  // beginning and end token position of the class.
  Function& func = Function::Handle();
  func = LookupClosureFunction(token_index);
  if (!func.IsNull()) {
    return func.raw();
  }
  Array& funcs = Array::Handle(functions());
  intptr_t len = funcs.Length();
  for (intptr_t i = 0; i < len; i++) {
    func ^= funcs.At(i);
    if ((func.token_index() <= token_index) &&
        (token_index < func.end_token_index())) {
      return func.raw();
    }
  }
  // No function found.
  return Function::null();
}


RawField* Class::LookupInstanceField(const String& name) const {
  ASSERT(is_finalized());
  const Field& field = Field::Handle(LookupField(name));
  if (!field.IsNull()) {
    if (field.is_static()) {
      // Name matches but it is not of the correct kind, return NULL.
      return Field::null();
    }
    return field.raw();
  }
  // No field found.
  return Field::null();
}


RawField* Class::LookupStaticField(const String& name) const {
  ASSERT(is_finalized());
  const Field& field = Field::Handle(LookupField(name));
  if (!field.IsNull()) {
    if (!field.is_static()) {
      // Name matches but it is not of the correct kind, return NULL.
      return Field::null();
    }
    return field.raw();
  }
  // No field found.
  return Field::null();
}


RawField* Class::LookupField(const String& name) const {
  Isolate* isolate = Isolate::Current();
  const Array& flds = Array::Handle(isolate, fields());
  Field& field = Field::Handle(isolate, Field::null());
  String& field_name = String::Handle(isolate, String::null());
  intptr_t len = flds.Length();
  for (intptr_t i = 0; i < len; i++) {
    field ^= flds.At(i);
    field_name ^= field.name();
    if (field_name.Equals(name) || MatchesPrivateName(field_name, name)) {
      return field.raw();
    }
  }
  // No field found.
  return Field::null();
}


RawLibraryPrefix* Class::LookupLibraryPrefix(const String& name) const {
  Isolate* isolate = Isolate::Current();
  LibraryPrefix& lib_prefix = LibraryPrefix::Handle(isolate,
                                                    LibraryPrefix::null());
  const Library& lib = Library::Handle(isolate, library());
  Object& obj = Object::Handle(isolate, lib.LookupLocalObject(name));
  if (!obj.IsNull()) {
    if (obj.IsLibraryPrefix()) {
      lib_prefix ^= obj.raw();
    }
  }
  return lib_prefix.raw();
}


const char* Class::ToCString() const {
  const char* format = is_interface()
      ? "%s Interface: %s" : "%s Class: %s";
  const Library& lib = Library::Handle(library());
  const char* library_name = lib.IsNull() ? "" : lib.ToCString();
  const char* class_name = String::Handle(Name()).ToCString();
  intptr_t len = OS::SNPrint(NULL, 0, format, library_name, class_name) + 1;
  char* chars = reinterpret_cast<char*>(
      Isolate::Current()->current_zone()->Allocate(len));
  OS::SNPrint(chars, len, format, library_name, class_name);
  return chars;
}


void Class::InsertCanonicalConstant(intptr_t index,
                                    const Instance& constant) const {
  // The constant needs to be added to the list. Grow the list if it is full.
  Array& canonical_list = Array::Handle(constants());
  const intptr_t list_len = canonical_list.Length();
  if (index >= list_len) {
    const intptr_t new_length = (list_len == 0) ? 4 : list_len + 4;
    const Array& new_canonical_list =
        Array::Handle(Array::Grow(canonical_list, new_length, Heap::kOld));
    set_constants(new_canonical_list);
    new_canonical_list.SetAt(index, constant);
  } else {
    canonical_list.SetAt(index, constant);
  }
}


RawUnresolvedClass* UnresolvedClass::New(const LibraryPrefix& library_prefix,
                                         const String& ident,
                                         intptr_t token_index) {
  const UnresolvedClass& type = UnresolvedClass::Handle(UnresolvedClass::New());
  type.set_library_prefix(library_prefix);
  type.set_ident(ident);
  type.set_token_index(token_index);
  return type.raw();
}


RawUnresolvedClass* UnresolvedClass::New() {
  const Class& unresolved_class_class =
      Class::Handle(Object::unresolved_class_class());
  RawObject* raw = Object::Allocate(unresolved_class_class,
                                    UnresolvedClass::InstanceSize(),
                                    Heap::kNew);
  return reinterpret_cast<RawUnresolvedClass*>(raw);
}


void UnresolvedClass::set_token_index(intptr_t token_index) const {
  ASSERT(token_index >= 0);
  raw_ptr()->token_index_ = token_index;
}


void UnresolvedClass::set_ident(const String& ident) const {
  StorePointer(&raw_ptr()->ident_, ident.raw());
}


void UnresolvedClass::set_library_prefix(
    const LibraryPrefix& library_prefix) const {
  StorePointer(&raw_ptr()->library_prefix_, library_prefix.raw());
}


void UnresolvedClass::set_factory_signature_class(const Class& value) const {
  StorePointer(&raw_ptr()->factory_signature_class_, value.raw());
}


RawString* UnresolvedClass::Name() const {
  if (library_prefix() != LibraryPrefix::null()) {
    const LibraryPrefix& lib_prefix = LibraryPrefix::Handle(library_prefix());
    String& name = String::Handle();
    String& str = String::Handle();
    name = lib_prefix.name();  // Qualifier.
    str = String::New(".");
    name = String::Concat(name, str);
    str = ident();
    name = String::Concat(name, str);
    return name.raw();
  } else {
    return ident();
  }
}


const char* UnresolvedClass::ToCString() const {
  return "UnresolvedClass";
}


bool AbstractType::IsResolved() const {
  // AbstractType is an abstract class.
  UNREACHABLE();
  return false;
}


bool AbstractType::HasResolvedTypeClass() const {
  // AbstractType is an abstract class.
  UNREACHABLE();
  return false;
}


RawClass* AbstractType::type_class() const {
  // AbstractType is an abstract class.
  UNREACHABLE();
  return Class::null();
}


RawUnresolvedClass* AbstractType::unresolved_class() const {
  // AbstractType is an abstract class.
  UNREACHABLE();
  return UnresolvedClass::null();
}


RawAbstractTypeArguments* AbstractType::arguments() const  {
  // AbstractType is an abstract class.
  UNREACHABLE();
  return NULL;
}


intptr_t AbstractType::token_index() const {
  // AbstractType is an abstract class.
  UNREACHABLE();
  return -1;
}


bool AbstractType::IsInstantiated() const {
  // AbstractType is an abstract class.
  UNREACHABLE();
  return false;
}


bool AbstractType::IsFinalized() const {
  // AbstractType is an abstract class.
  UNREACHABLE();
  return false;
}


bool AbstractType::IsBeingFinalized() const {
  // AbstractType is an abstract class.
  UNREACHABLE();
  return false;
}


bool AbstractType::IsMalformed() const {
  // AbstractType is an abstract class.
  UNREACHABLE();
  return false;
}


RawError* AbstractType::malformed_error() const {
  // AbstractType is an abstract class.
  UNREACHABLE();
  return Error::null();
}


void AbstractType::set_malformed_error(const Error& value) const {
  // AbstractType is an abstract class.
  UNREACHABLE();
}


bool AbstractType::Equals(const AbstractType& other) const {
  // AbstractType is an abstract class.
  UNREACHABLE();
  return false;
}


bool AbstractType::IsIdentical(const AbstractType& other) const {
  // AbstractType is an abstract class.
  UNREACHABLE();
  return false;
}


RawAbstractType* AbstractType::InstantiateFrom(
    const AbstractTypeArguments& instantiator_type_arguments) const {
  // AbstractType is an abstract class.
  UNREACHABLE();
  return NULL;
}


RawAbstractType* AbstractType::Canonicalize() const {
  // AbstractType is an abstract class.
  UNREACHABLE();
  return NULL;
}


RawString* AbstractType::Name() const {
  // If the type is still being finalized, we may be reporting an error about
  // an illformed type, so proceed with caution.
  const AbstractTypeArguments& args =
      AbstractTypeArguments::Handle(arguments());
  const intptr_t num_args = args.IsNull() ? 0 : args.Length();
  String& class_name = String::Handle();
  intptr_t first_type_param_index;
  intptr_t num_type_params;  // Number of type parameters to print.
  if (HasResolvedTypeClass()) {
    const Class& cls = Class::Handle(type_class());
    class_name = cls.Name();
    num_type_params = cls.NumTypeParameters();  // Do not print the full vector.
    if (num_type_params > num_args) {
      first_type_param_index = 0;
      if (!IsFinalized() || IsBeingFinalized()) {
        // Most probably an illformed type. Do not fill up with "Dynamic",
        // but use actual vector.
        num_type_params = num_args;
      } else {
        ASSERT(num_args == 0);  // Type is raw.
        // No need to fill up with "Dynamic".
        num_type_params = 0;
      }
    } else {
      first_type_param_index = num_args - num_type_params;
    }
    if (cls.IsSignatureClass()) {
      // We may be reporting an error about an illformed function type. In that
      // case, avoid instantiating the signature, since it may lead to cycles.
      if (!IsFinalized() || IsBeingFinalized()) {
        return class_name.raw();
      }
      const Function& signature_function = Function::Handle(
          cls.signature_function());
      // Signature classes have no super type.
      ASSERT(first_type_param_index == 0);
      return signature_function.InstantiatedSignatureFrom(args);
    }
  } else {
    const UnresolvedClass& cls = UnresolvedClass::Handle(unresolved_class());
    class_name = cls.Name();
    num_type_params = num_args;
    first_type_param_index = 0;
  }
  String& type_name = String::Handle();
  if (num_type_params == 0) {
    type_name = class_name.raw();
  } else {
    const String& args_name = String::Handle(
        args.SubvectorName(first_type_param_index, num_type_params));
    type_name = String::Concat(class_name, args_name);
  }
  // The name is only used for type checking and debugging purposes.
  // Unless profiling data shows otherwise, it is not worth caching the name in
  // the type.
  return String::NewSymbol(type_name);
}


intptr_t AbstractType::Index() const {
  // AbstractType is an abstract class.
  UNREACHABLE();
  return -1;
}


RawString* AbstractType::ClassName() const {
  if (HasResolvedTypeClass()) {
    return Class::Handle(type_class()).Name();
  } else {
    return UnresolvedClass::Handle(unresolved_class()).Name();
  }
}


bool AbstractType::IsBoolInterface() const {
  return HasResolvedTypeClass() &&
      (type_class() == Type::Handle(Type::BoolInterface()).type_class());
}


bool AbstractType::IsIntInterface() const {
  return HasResolvedTypeClass() &&
      (type_class() == Type::Handle(Type::IntInterface()).type_class());
}


bool AbstractType::IsDoubleInterface() const {
  return HasResolvedTypeClass() &&
      (type_class() == Type::Handle(Type::DoubleInterface()).type_class());
}


bool AbstractType::IsNumberInterface() const {
  return HasResolvedTypeClass() &&
      (type_class() == Type::Handle(Type::NumberInterface()).type_class());
}


bool AbstractType::IsStringInterface() const {
  return HasResolvedTypeClass() &&
      (type_class() == Type::Handle(Type::StringInterface()).type_class());
}


bool AbstractType::IsFunctionInterface() const {
  return HasResolvedTypeClass() &&
      (type_class() == Type::Handle(Type::FunctionInterface()).type_class());
}


bool AbstractType::IsListInterface() const {
  return HasResolvedTypeClass() &&
      (type_class() == Type::Handle(Type::ListInterface()).type_class());
}


bool AbstractType::IsSubtypeOf(const AbstractType& other,
                               Error* malformed_error) const {
  ASSERT(IsFinalized());
  ASSERT(other.IsFinalized());
  // AbstractType parameters cannot be handled by Class::IsSubtypeOf().
  if (IsTypeParameter() || other.IsTypeParameter()) {
    // An uninstantiated type parameter is equivalent to Dynamic.
    return true;
  }
  const Class& cls = Class::Handle(type_class());
  return cls.IsSubtypeOf(AbstractTypeArguments::Handle(arguments()),
                         Class::Handle(other.type_class()),
                         AbstractTypeArguments::Handle(other.arguments()),
                         malformed_error);
}

RawAbstractType* AbstractType::NewTypeParameter(const Class& clazz,
                                                intptr_t index,
                                                const String& name,
                                                intptr_t token_index) {
  return TypeParameter::New(clazz, index, name, token_index);
}


RawAbstractType* AbstractType::NewInstantiatedType(
    const AbstractType& uninstantiated_type,
    const AbstractTypeArguments& instantiator_type_arguments) {
  return InstantiatedType::New(uninstantiated_type,
                               instantiator_type_arguments);
}


const char* AbstractType::ToCString() const {
  // AbstractType is an abstract class.
  UNREACHABLE();
  return "AbstractType";
}


RawType* Type::NullType() {
  return Isolate::Current()->object_store()->null_type();
}


RawType* Type::DynamicType() {
  return Isolate::Current()->object_store()->dynamic_type();
}


RawType* Type::VoidType() {
  return Isolate::Current()->object_store()->void_type();
}


RawType* Type::ObjectType() {
  return Isolate::Current()->object_store()->object_type();
}


RawType* Type::BoolInterface() {
  return Isolate::Current()->object_store()->bool_interface();
}


RawType* Type::IntInterface() {
  return Isolate::Current()->object_store()->int_interface();
}


RawType* Type::DoubleInterface() {
  return Isolate::Current()->object_store()->double_interface();
}


RawType* Type::NumberInterface() {
  return Isolate::Current()->object_store()->number_interface();
}


RawType* Type::StringInterface() {
  return Isolate::Current()->object_store()->string_interface();
}


RawType* Type::FunctionInterface() {
  return Isolate::Current()->object_store()->function_interface();
}


RawType* Type::ListInterface() {
  return Isolate::Current()->object_store()->list_interface();
}


RawType* Type::NewNonParameterizedType(
    const Class& type_class) {
  ASSERT(!type_class.HasTypeArguments());
  const TypeArguments& no_type_arguments = TypeArguments::Handle();
  Type& type = Type::Handle();
  type ^= Type::New(Object::Handle(type_class.raw()),
                    no_type_arguments,
                    Scanner::kDummyTokenIndex);
  type.set_is_finalized();
  type ^= type.Canonicalize();
  return type.raw();
}


void Type::set_is_finalized() const {
  ASSERT(!IsFinalized());
  set_type_state(RawType::kFinalized);
}


void Type::set_is_being_finalized() const {
  ASSERT(!IsFinalized() && !IsBeingFinalized());
  set_type_state(RawType::kBeingFinalized);
}


bool Type::IsMalformed() const {
  return raw_ptr()->malformed_error_ != Error::null();
}


void Type::set_malformed_error(const Error& value) const {
  StorePointer(&raw_ptr()->malformed_error_, value.raw());
}


RawError* Type::malformed_error() const {
  ASSERT(IsMalformed());
  return raw_ptr()->malformed_error_;
}


bool Type::IsResolved() const {
  if (IsFinalized()) {
    return true;
  }
  if (!HasResolvedTypeClass()) {
    return false;
  }
  const AbstractTypeArguments& args =
      AbstractTypeArguments::Handle(arguments());
  return args.IsNull() || args.IsResolved();
}


bool Type::HasResolvedTypeClass() const {
  const Object& type_class = Object::Handle(raw_ptr()->type_class_);
  return !type_class.IsNull() && type_class.IsClass();
}


RawClass* Type::type_class() const {
  ASSERT(HasResolvedTypeClass());
  Class& type_class = Class::Handle();
  type_class ^= raw_ptr()->type_class_;
  return type_class.raw();
}


RawUnresolvedClass* Type::unresolved_class() const {
  ASSERT(!HasResolvedTypeClass());
  UnresolvedClass& unresolved_class = UnresolvedClass::Handle();
  unresolved_class ^= raw_ptr()->type_class_;
  ASSERT(!unresolved_class.IsNull());
  return unresolved_class.raw();
}


RawString* Type::TypeClassName() const {
  if (HasResolvedTypeClass()) {
    const Class& cls = Class::Handle(type_class());
    return cls.Name();
  } else {
    const UnresolvedClass& cls = UnresolvedClass::Handle(unresolved_class());
    return cls.Name();
  }
}


RawAbstractTypeArguments* Type::arguments() const {
  return raw_ptr()->arguments_;
}


bool Type::IsInstantiated() const {
  const AbstractTypeArguments& args =
      AbstractTypeArguments::Handle(arguments());
  return args.IsNull() || args.IsInstantiated();
}


RawAbstractType* Type::InstantiateFrom(
    const AbstractTypeArguments& instantiator_type_arguments) const {
  ASSERT(IsFinalized());
  ASSERT(!IsInstantiated());
  AbstractTypeArguments& type_arguments =
      AbstractTypeArguments::Handle(arguments());
  type_arguments = type_arguments.InstantiateFrom(instantiator_type_arguments);
  const Class& cls = Class::Handle(type_class());
  ASSERT(cls.is_finalized());
  Type& instantiated_type = Type::Handle(
      Type::New(cls, type_arguments, token_index()));
  ASSERT(type_arguments.IsNull() ||
         (type_arguments.Length() == cls.NumTypeArguments()));
  instantiated_type.set_is_finalized();
  return instantiated_type.raw();
}


bool Type::Equals(const AbstractType& other) const {
  ASSERT(IsFinalized() && other.IsFinalized());
  if (raw() == other.raw()) {
    return true;
  }
  if (IsMalformed() || !other.IsType() || other.IsMalformed()) {
    return false;
  }
  Type& other_type = Type::Handle();
  other_type ^= other.raw();
  if (type_class() != other_type.type_class()) {
    return false;
  }
  return AbstractTypeArguments::AreEqual(
      AbstractTypeArguments::Handle(arguments()),
      AbstractTypeArguments::Handle(other.arguments()));
}


bool Type::IsIdentical(const AbstractType& other) const {
  if (raw() == other.raw()) {
    return true;
  }
  if (!other.IsType()) {
    return false;
  }
  Type& other_type = Type::Handle();
  other_type ^= other.raw();
  // Both type classes may not be resolved yet.
  String& name = String::Handle(TypeClassName());
  String& other_name = String::Handle(other_type.TypeClassName());
  if (!name.Equals(other_name)) {
    return false;
  }
  return AbstractTypeArguments::AreIdentical(
      AbstractTypeArguments::Handle(arguments()),
      AbstractTypeArguments::Handle(other.arguments()));
}


RawAbstractType* Type::Canonicalize() const {
  ASSERT(IsFinalized());
  const Class& cls = Class::Handle(type_class());
  Array& canonical_types = Array::Handle(cls.canonical_types());
  if (canonical_types.IsNull()) {
    // Types defined in the VM isolate are canonicalized via the object store.
    return this->raw();
  }
  if (!IsCanonical()) {
    const intptr_t canonical_types_len = canonical_types.Length();
    // Linear search to see whether this type is already present in the
    // list of canonicalized types.
    // TODO(asiva): Try to re-factor this lookup code to make sharing
    // easy between the 4 versions of this loop.
    Type& type = Type::Handle();
    intptr_t index = 0;
    while (index < canonical_types_len) {
      type ^= canonical_types.At(index);
      if (type.IsNull()) {
        break;
      }
      if (!type.IsFinalized()) {
        ASSERT((index == 0) && cls.IsSignatureClass());
        index++;
        continue;
      }
      if (this->Equals(type)) {
        return type.raw();
      }
      index++;
    }
    // The type needs to be added to the list. Grow the list if it is full.
    if (index == canonical_types_len) {
      const intptr_t kLengthIncrement = 2;  // Raw and parameterized.
      const intptr_t new_length = canonical_types.Length() + kLengthIncrement;
      const Array& new_canonical_types =
          Array::Handle(Array::Grow(canonical_types, new_length, Heap::kOld));
      cls.set_canonical_types(new_canonical_types);
      new_canonical_types.SetAt(index, *this);
    } else {
      canonical_types.SetAt(index, *this);
    }
    SetCanonical();
  }
  return this->raw();
}


void Type::set_type_class(const Object& value) const {
  ASSERT(!value.IsNull() && (value.IsClass() || value.IsUnresolvedClass()));
  StorePointer(&raw_ptr()->type_class_, value.raw());
}


void Type::set_arguments(const AbstractTypeArguments& value) const {
  StorePointer(&raw_ptr()->arguments_, value.raw());
}


RawType* Type::New() {
  const Class& type_class = Class::Handle(Object::type_class());
  RawObject* raw = Object::Allocate(type_class,
                                    Type::InstanceSize(),
                                    Heap::kOld);
  return reinterpret_cast<RawType*>(raw);
}


RawType* Type::New(const Object& clazz,
                   const AbstractTypeArguments& arguments,
                   intptr_t token_index) {
  const Type& result = Type::Handle(Type::New());
  result.set_type_class(clazz);
  result.set_arguments(arguments);
  result.set_token_index(token_index);
  result.raw_ptr()->type_state_ = RawType::kAllocated;
  return result.raw();
}


void Type::set_token_index(intptr_t token_index) const {
  ASSERT(token_index >= 0);
  raw_ptr()->token_index_ = token_index;
}


void Type::set_type_state(int8_t state) const {
  ASSERT(state == RawType::kAllocated ||
         state == RawType::kBeingFinalized ||
         state == RawType::kFinalized);
  raw_ptr()->type_state_ = state;
}


const char* Type::ToCString() const {
  if (IsResolved()) {
    const AbstractTypeArguments& type_arguments =
        AbstractTypeArguments::Handle(arguments());
    if (type_arguments.IsNull()) {
      const char* format = "Type: class '%s'";
      const char* class_name =
          String::Handle(Class::Handle(type_class()).Name()).ToCString();
      intptr_t len = OS::SNPrint(NULL, 0, format, class_name) + 1;
      char* chars = reinterpret_cast<char*>(
          Isolate::Current()->current_zone()->Allocate(len));
      OS::SNPrint(chars, len, format, class_name);
      return chars;
    } else {
      const char* format = "Type: class '%s', args:[%s]";
      const char* class_name =
          String::Handle(Class::Handle(type_class()).Name()).ToCString();
      const char* args_cstr =
          AbstractTypeArguments::Handle(arguments()).ToCString();
      intptr_t len = OS::SNPrint(NULL, 0, format, class_name, args_cstr) + 1;
      char* chars = reinterpret_cast<char*>(
          Isolate::Current()->current_zone()->Allocate(len));
      OS::SNPrint(chars, len, format, class_name, args_cstr);
      return chars;
    }
  } else {
    return "Unresolved Type";
  }
}


void TypeParameter::set_is_finalized() const {
  ASSERT(!IsFinalized());
  set_type_state(RawTypeParameter::kFinalized);
  // Field parameterized_class_ is not needed after finalization anymore.
  set_parameterized_class(Class::Handle());
}


bool TypeParameter::Equals(const AbstractType& other) const {
  if (raw() == other.raw()) {
    return true;
  }
  if (!other.IsTypeParameter()) {
    return false;
  }
  TypeParameter& other_type_param = TypeParameter::Handle();
  other_type_param ^= other.raw();
  if (IsFinalized() != other_type_param.IsFinalized()) {
    return false;
  }
  if (parameterized_class() != other_type_param.parameterized_class()) {
    return false;
  }
  if (Index() != other_type_param.Index()) {
    return false;
  }
  const String& name = String::Handle(Name());
  const String& other_type_param_name = String::Handle(other_type_param.Name());
  return name.Equals(other_type_param_name);
}


bool TypeParameter::IsIdentical(const AbstractType& other) const {
  if (raw() == other.raw()) {
    return true;
  }
  if (!other.IsTypeParameter()) {
    return false;
  }
  TypeParameter& other_type_param = TypeParameter::Handle();
  other_type_param ^= other.raw();
  // Both type parameters may have different type_class and their index may be
  // different after finalization, which is OK. Do not check.
  String& name = String::Handle(Name());
  String& other_name = String::Handle(other_type_param.Name());
  return name.Equals(other_name);
}


void TypeParameter::set_parameterized_class(const Class& value) const {
  // Set value may be null.
  StorePointer(&raw_ptr()->parameterized_class_, value.raw());
}


void TypeParameter::set_index(intptr_t value) const {
  ASSERT(value >= 0);
  raw_ptr()->index_ = value;
}


void TypeParameter::set_name(const String& value) const {
  ASSERT(value.IsSymbol());
  StorePointer(&raw_ptr()->name_, value.raw());
}


RawAbstractType* TypeParameter::InstantiateFrom(
    const AbstractTypeArguments& instantiator_type_arguments) const {
  ASSERT(IsFinalized());
  if (instantiator_type_arguments.IsNull()) {
    return Type::DynamicType();
  }
  return instantiator_type_arguments.TypeAt(Index());
}


RawTypeParameter* TypeParameter::New() {
  const Class& type_parameter_class =
      Class::Handle(Object::type_parameter_class());
  RawObject* raw = Object::Allocate(type_parameter_class,
                                    TypeParameter::InstanceSize(),
                                    Heap::kOld);
  return reinterpret_cast<RawTypeParameter*>(raw);
}


RawTypeParameter* TypeParameter::New(const Class& parameterized_class,
                                     intptr_t index,
                                     const String& name,
                                     intptr_t token_index) {
  const TypeParameter& result = TypeParameter::Handle(TypeParameter::New());
  result.set_parameterized_class(parameterized_class);
  result.set_index(index);
  result.set_name(name);
  result.set_token_index(token_index);
  result.raw_ptr()->type_state_ = RawTypeParameter::kAllocated;
  return result.raw();
}


void TypeParameter::set_token_index(intptr_t token_index) const {
  ASSERT(token_index >= 0);
  raw_ptr()->token_index_ = token_index;
}


void TypeParameter::set_type_state(int8_t state) const {
  ASSERT(state == RawTypeParameter::kAllocated ||
         state == RawTypeParameter::kBeingFinalized ||
         state == RawTypeParameter::kFinalized);
  raw_ptr()->type_state_ = state;
}


const char* TypeParameter::ToCString() const {
  const char* format = "TypeParameter: name %s; index: %d";
  const char* name_cstr = String::Handle(Name()).ToCString();
  intptr_t len = OS::SNPrint(NULL, 0, format, name_cstr, Index()) + 1;
  char* chars = reinterpret_cast<char*>(
      Isolate::Current()->current_zone()->Allocate(len));
  OS::SNPrint(chars, len, format, name_cstr, Index());
  return chars;
}


RawClass* InstantiatedType::type_class() const {
  return AbstractType::Handle(uninstantiated_type()).type_class();
}


RawAbstractTypeArguments* InstantiatedType::arguments() const {
  return InstantiatedTypeArguments::New(
      AbstractTypeArguments::Handle(AbstractType::Handle(
          uninstantiated_type()).arguments()),
      AbstractTypeArguments::Handle(instantiator_type_arguments()));
}


intptr_t InstantiatedType::token_index() const {
  return AbstractType::Handle(uninstantiated_type()).token_index();
}


void InstantiatedType::set_uninstantiated_type(
    const AbstractType& value) const {
  StorePointer(&raw_ptr()->uninstantiated_type_, value.raw());
}


void InstantiatedType::set_instantiator_type_arguments(
    const AbstractTypeArguments& value) const {
  StorePointer(&raw_ptr()->instantiator_type_arguments_, value.raw());
}


RawInstantiatedType* InstantiatedType::New() {
  const Class& instantiated_type_class =
      Class::Handle(Object::instantiated_type_class());
  RawObject* raw = Object::Allocate(instantiated_type_class,
                                    InstantiatedType::InstanceSize(),
                                    Heap::kOld);
  return reinterpret_cast<RawInstantiatedType*>(raw);
}


RawInstantiatedType* InstantiatedType::New(
    const AbstractType& uninstantiated_type,
    const AbstractTypeArguments& instantiator_type_arguments) {
  const InstantiatedType& result =
      InstantiatedType::Handle(InstantiatedType::New());
  result.set_uninstantiated_type(uninstantiated_type);
  result.set_instantiator_type_arguments(instantiator_type_arguments);
  return result.raw();
}


const char* InstantiatedType::ToCString() const {
  return "InstantiatedType";
}


intptr_t AbstractTypeArguments::Length() const  {
  // AbstractTypeArguments is an abstract class.
  UNREACHABLE();
  return -1;
}


RawAbstractType* AbstractTypeArguments::TypeAt(intptr_t index) const {
  // AbstractTypeArguments is an abstract class.
  UNREACHABLE();
  return NULL;
}


void AbstractTypeArguments::SetTypeAt(intptr_t index,
                                      const AbstractType& value) const {
  // AbstractTypeArguments is an abstract class.
  UNREACHABLE();
}


bool AbstractTypeArguments::IsResolved() const {
  // AbstractTypeArguments is an abstract class.
  UNREACHABLE();
  return false;
}


bool AbstractTypeArguments::IsInstantiated() const {
  // AbstractTypeArguments is an abstract class.
  UNREACHABLE();
  return false;
}


bool AbstractTypeArguments::IsUninstantiatedIdentity() const {
  // AbstractTypeArguments is an abstract class.
  UNREACHABLE();
  return false;
}


RawString* AbstractTypeArguments::SubvectorName(intptr_t from_index,
                                                intptr_t len) const {
  ASSERT(from_index + len <= Length());
  String& name = String::Handle();
  const intptr_t num_strings = 2*len + 1;  // "<""T"", ""T"">".
  const Array& strings = Array::Handle(Array::New(num_strings));
  intptr_t s = 0;
  strings.SetAt(s++, String::Handle(String::NewSymbol("<")));
  const String& kCommaSpace = String::Handle(String::NewSymbol(", "));
  AbstractType& type = AbstractType::Handle();
  for (intptr_t i = 0; i < len; i++) {
    type = TypeAt(from_index + i);
    name = type.Name();
    strings.SetAt(s++, name);
    if (i < len - 1) {
      strings.SetAt(s++, kCommaSpace);
    }
  }
  strings.SetAt(s++, String::Handle(String::NewSymbol(">")));
  ASSERT(s == num_strings);
  name = String::ConcatAll(strings);
  return String::NewSymbol(name);
}


bool AbstractTypeArguments::Equals(const AbstractTypeArguments& other) const {
  ASSERT(!IsNull());  // Use AbstractTypeArguments::AreEqual().
  if (this->raw() == other.raw()) {
    return true;
  }
  if (other.IsNull()) {
    return false;
  }
  intptr_t num_types = Length();
  if (num_types != other.Length()) {
    return false;
  }
  AbstractType& type = AbstractType::Handle();
  AbstractType& other_type = AbstractType::Handle();
  for (intptr_t i = 0; i < num_types; i++) {
    type = TypeAt(i);
    other_type = other.TypeAt(i);
    if (!type.Equals(other_type)) {
      return false;
    }
  }
  return true;
}


bool AbstractTypeArguments::AreEqual(
    const AbstractTypeArguments& arguments,
    const AbstractTypeArguments& other_arguments) {
  if (arguments.raw() == other_arguments.raw()) {
    return true;
  }
  if (arguments.IsNull()) {
    return other_arguments.IsDynamicTypes(false, other_arguments.Length());
  }
  if (other_arguments.IsNull()) {
    return arguments.IsDynamicTypes(false, arguments.Length());
  }
  return arguments.Equals(other_arguments);
}


bool AbstractTypeArguments::AreIdentical(
    const AbstractTypeArguments& arguments,
    const AbstractTypeArguments& other_arguments) {
  if (arguments.raw() == other_arguments.raw()) {
    return true;
  }
  if (arguments.IsNull() || other_arguments.IsNull()) {
    return false;
  }
  intptr_t num_types = arguments.Length();
  if (num_types != other_arguments.Length()) {
    return false;
  }
  AbstractType& type = AbstractType::Handle();
  AbstractType& other_type = AbstractType::Handle();
  for (intptr_t i = 0; i < num_types; i++) {
    type ^= arguments.TypeAt(i);
    ASSERT(!type.IsNull());
    other_type ^= other_arguments.TypeAt(i);
    if (!type.IsIdentical(other_type)) {
      return false;
    }
  }
  return true;
}


RawAbstractTypeArguments* AbstractTypeArguments::InstantiateFrom(
    const AbstractTypeArguments& instantiator_type_arguments) const {
  // AbstractTypeArguments is an abstract class.
  UNREACHABLE();
  return NULL;
}


bool AbstractTypeArguments::IsDynamicTypes(bool raw_instantiated,
                                           intptr_t len) const {
  ASSERT(Length() >= len);
  AbstractType& type = AbstractType::Handle();
  Class& type_class = Class::Handle();
  for (intptr_t i = 0; i < len; i++) {
    type = TypeAt(i);
    ASSERT(!type.IsNull());
    if (!type.HasResolvedTypeClass()) {
      if (raw_instantiated && type.IsTypeParameter()) {
        // An uninstantiated type parameter is equivalent to Dynamic.
        continue;
      }
      ASSERT((!raw_instantiated && type.IsTypeParameter()) ||
             type.IsMalformed());
      return false;
    }
    type_class = type.type_class();
    if (!type_class.IsDynamicClass()) {
      return false;
    }
  }
  return true;
}


static RawError* FormatError(const Error& prev_error,
                             const Script& script,
                             intptr_t token_index,
                             const char* format, ...) {
  va_list args;
  va_start(args, format);
  if (prev_error.IsNull()) {
    return Parser::FormatError(script, token_index, "Error", format, args);
  } else {
    return Parser::FormatErrorWithAppend(prev_error, script, token_index,
                                         "Error", format, args);
  }
}


bool AbstractTypeArguments::IsWithinBoundsOf(
    const Class& cls,
    const AbstractTypeArguments& bounds_instantiator,
    Error* malformed_error) const {
  ASSERT(FLAG_enable_type_checks);
  ASSERT(IsInstantiated());
  ASSERT(Length() >= cls.NumTypeArguments());
  const intptr_t num_type_params = cls.NumTypeParameters();
  const intptr_t offset = cls.NumTypeArguments() - num_type_params;
  AbstractType& type = AbstractType::Handle();
  AbstractType& bound = AbstractType::Handle();
  const TypeArguments& bounds =
      TypeArguments::Handle(cls.type_parameter_bounds());
  ASSERT((bounds.IsNull() && (num_type_params == 0)) ||
         (bounds.Length() == num_type_params));
  for (intptr_t i = 0; i < num_type_params; i++) {
    bound = bounds.TypeAt(i);
    if (!bound.IsDynamicType()) {
      type = TypeAt(offset + i);
      Error& malformed_bound_error = Error::Handle();
      if (bound.IsMalformed()) {
        malformed_bound_error = bound.malformed_error();
      } else if (!bound.IsInstantiated()) {
        bound = bound.InstantiateFrom(bounds_instantiator);
      }
      if (!malformed_bound_error.IsNull() ||
          !type.IsSubtypeOf(bound, malformed_error)) {
        // Ignore this bound error if another malformed error was already
        // reported for this type test.
        if (malformed_error->IsNull()) {
          const String& type_argument_name = String::Handle(type.Name());
          const String& class_name = String::Handle(cls.Name());
          const String& bound_name = String::Handle(bound.Name());
          const Script& script = Script::Handle(cls.script());
          // Since the bound was canonicalized, its token index was lost,
          // therefore, use the token index of the corresponding type parameter.
          const TypeArguments& type_parameters =
              TypeArguments::Handle(cls.type_parameters());
          type = type_parameters.TypeAt(i);
          *malformed_error ^= FormatError(malformed_bound_error,
                                          script, type.token_index(),
                                          "type argument '%s' does not "
                                          "extend bound '%s' of '%s'\n",
                                          type_argument_name.ToCString(),
                                          bound_name.ToCString(),
                                          class_name.ToCString());
        }
        return false;
      }
    }
  }
  const Class& super_class = Class::Handle(cls.SuperClass());
  if (!super_class.IsNull() &&
      !IsWithinBoundsOf(super_class, bounds_instantiator, malformed_error)) {
    return false;
  }
  return true;
}


bool AbstractTypeArguments::IsSubtypeOf(
    const AbstractTypeArguments& other,
    intptr_t len,
    Error* malformed_error) const {
  ASSERT(Length() >= len);
  ASSERT(!other.IsNull());
  ASSERT(other.Length() >= len);
  AbstractType& type = AbstractType::Handle();
  AbstractType& other_type = AbstractType::Handle();
  for (intptr_t i = 0; i < len; i++) {
    type = TypeAt(i);
    ASSERT(!type.IsNull());
    other_type = other.TypeAt(i);
    ASSERT(!other_type.IsNull());
    if (!type.IsSubtypeOf(other_type, malformed_error)) {
      return false;
    }
  }
  return true;
}


const char* AbstractTypeArguments::ToCString() const {
  // AbstractTypeArguments is an abstract class, valid only for representing
  // null.
  if (IsNull()) {
    return "NULL AbstractTypeArguments";
  }
  UNREACHABLE();
  return "AbstractTypeArguments";
}


intptr_t TypeArguments::Length() const {
  ASSERT(!IsNull());
  return Smi::Value(raw_ptr()->length_);
}


RawAbstractType* TypeArguments::TypeAt(intptr_t index) const {
  return *TypeAddr(index);
}


void TypeArguments::SetTypeAt(intptr_t index, const AbstractType& value) const {
  ASSERT(!IsCanonical());
  // TODO(iposva): Add storing NoGCScope.
  *TypeAddr(index) = value.raw();
}


bool TypeArguments::IsResolved() const {
  AbstractType& type = AbstractType::Handle();
  intptr_t num_types = Length();
  for (intptr_t i = 0; i < num_types; i++) {
    type = TypeAt(i);
    if (!type.IsResolved()) {
      return false;
    }
  }
  return true;
}


bool TypeArguments::IsInstantiated() const {
  AbstractType& type = AbstractType::Handle();
  intptr_t num_types = Length();
  for (intptr_t i = 0; i < num_types; i++) {
    type = TypeAt(i);
    ASSERT(!type.IsNull());
    if (!type.IsInstantiated()) {
      return false;
    }
  }
  return true;
}


bool TypeArguments::IsUninstantiatedIdentity() const {
  ASSERT(!IsInstantiated());
  AbstractType& type = AbstractType::Handle();
  intptr_t num_types = Length();
  for (intptr_t i = 0; i < num_types; i++) {
    type = TypeAt(i);
    if (!type.IsTypeParameter() || (type.Index() != i)) {
      return false;
    }
  }
  return true;
}


RawAbstractTypeArguments* TypeArguments::InstantiateFrom(
    const AbstractTypeArguments& instantiator_type_arguments) const {
  ASSERT(!IsInstantiated());
  if (!instantiator_type_arguments.IsNull() &&
      IsUninstantiatedIdentity() &&
      (instantiator_type_arguments.Length() == Length())) {
    return instantiator_type_arguments.raw();
  }
  const intptr_t num_types = Length();
  TypeArguments& instantiated_array =
      TypeArguments::Handle(TypeArguments::New(num_types));
  AbstractType& type = AbstractType::Handle();
  for (intptr_t i = 0; i < num_types; i++) {
    type = TypeAt(i);
    if (!type.IsInstantiated()) {
      type = type.InstantiateFrom(instantiator_type_arguments);
    }
    instantiated_array.SetTypeAt(i, type);
  }
  return instantiated_array.raw();
}


RawTypeArguments* TypeArguments::New(intptr_t len) {
  if ((len < 0) || (len > kMaxTypes)) {
    // TODO(iposva): Should we throw an illegal parameter exception?
    UNIMPLEMENTED();
    return null();
  }

  const Class& type_arguments_class =
      Class::Handle(Object::type_arguments_class());
  TypeArguments& result = TypeArguments::Handle();
  {
    RawObject* raw = Object::Allocate(type_arguments_class,
                                      TypeArguments::InstanceSize(len),
                                      Heap::kOld);
    NoGCScope no_gc;
    result ^= raw;
    // Length must be set before we start storing into the array.
    result.SetLength(len);
  }
  return result.raw();
}



RawAbstractType** TypeArguments::TypeAddr(intptr_t index) const {
  // TODO(iposva): Determine if we should throw an exception here.
  ASSERT((index >= 0) && (index < Length()));
  return &raw_ptr()->types_[index];
}


void TypeArguments::SetLength(intptr_t value) {
  ASSERT(!IsCanonical());
  // This is only safe because we create a new Smi, which does not cause
  // heap allocation.
  raw_ptr()->length_ = Smi::New(value);
}


RawAbstractTypeArguments* TypeArguments::Canonicalize() const {
  if (IsNull() || IsCanonical() || !IsInstantiated()) {
    return this->raw();
  }
  ObjectStore* object_store = Isolate::Current()->object_store();
  // 'table' must be null terminated.
  Array& table = Array::Handle(object_store->canonical_type_arguments());
  ASSERT(table.Length() > 0);
  intptr_t index = 0;
  TypeArguments& other = TypeArguments::Handle();
  other ^= table.At(index);
  while (!other.IsNull()) {
    if (this->Equals(other)) {
      return other.raw();
    }
    other ^= table.At(++index);
  }
  // Not found. Add 'this' to table.
  if (index == table.Length() - 1) {
    table = Array::Grow(table, table.Length() + 4, Heap::kOld);
    object_store->set_canonical_type_arguments(table);
  }
  table.SetAt(index, *this);
  SetCanonical();
  return this->raw();
}


const char* TypeArguments::ToCString() const {
  if (IsNull()) {
    return "NULL TypeArguments";
  }
  const char* format = "%s [%s]";
  const char* prev_cstr = "TypeArguments:";
  for (int i = 0; i < Length(); i++) {
    const AbstractType& type_at = AbstractType::Handle(TypeAt(i));
    const char* type_cstr = type_at.IsNull() ? "null" : type_at.ToCString();
    intptr_t len = OS::SNPrint(NULL, 0, format, prev_cstr, type_cstr) + 1;
    char* chars = reinterpret_cast<char*>(
        Isolate::Current()->current_zone()->Allocate(len));
    OS::SNPrint(chars, len, format, prev_cstr, type_cstr);
    prev_cstr = chars;
  }
  return prev_cstr;
}


intptr_t InstantiatedTypeArguments::Length() const {
  return AbstractTypeArguments::Handle(
      uninstantiated_type_arguments()).Length();
}


RawAbstractType* InstantiatedTypeArguments::TypeAt(intptr_t index) const {
  const AbstractType& type = AbstractType::Handle(
      AbstractTypeArguments::Handle(
          uninstantiated_type_arguments()).TypeAt(index));
  if (type.IsTypeParameter()) {
    AbstractTypeArguments& instantiator =
        AbstractTypeArguments::Handle(instantiator_type_arguments());
    if (instantiator.IsNull()) {
      return Type::DynamicType();
    }
    return instantiator.TypeAt(type.Index());
  }
  if (!type.IsInstantiated()) {
    return InstantiatedType::New(
        type, AbstractTypeArguments::Handle(instantiator_type_arguments()));
  }
  return type.raw();
}


void InstantiatedTypeArguments::SetTypeAt(intptr_t index,
                                          const AbstractType& value) const {
  // We only replace individual argument types during resolution at compile
  // time, when no type parameters are instantiated yet.
  UNREACHABLE();
}


void InstantiatedTypeArguments::set_uninstantiated_type_arguments(
    const AbstractTypeArguments& value) const {
  StorePointer(&raw_ptr()->uninstantiated_type_arguments_, value.raw());
}


void InstantiatedTypeArguments::set_instantiator_type_arguments(
    const AbstractTypeArguments& value) const {
  StorePointer(&raw_ptr()->instantiator_type_arguments_, value.raw());
}


RawInstantiatedTypeArguments* InstantiatedTypeArguments::New() {
  const Class& instantiated_type_arguments_class =
      Class::Handle(Object::instantiated_type_arguments_class());
  RawObject* raw = Object::Allocate(instantiated_type_arguments_class,
                                    InstantiatedTypeArguments::InstanceSize(),
                                    Heap::kNew);
  return reinterpret_cast<RawInstantiatedTypeArguments*>(raw);
}


RawInstantiatedTypeArguments* InstantiatedTypeArguments::New(
    const AbstractTypeArguments& uninstantiated_type_arguments,
    const AbstractTypeArguments& instantiator_type_arguments) {
  const InstantiatedTypeArguments& result =
      InstantiatedTypeArguments::Handle(InstantiatedTypeArguments::New());
  result.set_uninstantiated_type_arguments(uninstantiated_type_arguments);
  result.set_instantiator_type_arguments(instantiator_type_arguments);
  return result.raw();
}


const char* InstantiatedTypeArguments::ToCString() const {
  if (IsNull()) {
    return "NULL InstantiatedTypeArguments";
  }
  const char* format = "InstantiatedTypeArguments: [%s] instantiator: [%s]";
  const char* arg_cstr =
      AbstractTypeArguments::Handle(
          uninstantiated_type_arguments()).ToCString();
  const char* instantiator_cstr =
      AbstractTypeArguments::Handle(instantiator_type_arguments()).ToCString();
  intptr_t len =
      OS::SNPrint(NULL, 0, format, arg_cstr, instantiator_cstr) + 1;
  char* chars = reinterpret_cast<char*>(
      Isolate::Current()->current_zone()->Allocate(len));
  OS::SNPrint(chars, len, format, arg_cstr, instantiator_cstr);
  return chars;
}


void Function::SetCode(const Code& value) const {
  StorePointer(&raw_ptr()->code_, value.raw());
  ASSERT(Function::Handle(value.function()).IsNull() ||
    (value.function() == this->raw()));
  value.set_function(*this);
}


void Function::set_unoptimized_code(const Code& value) const {
  StorePointer(&raw_ptr()->unoptimized_code_, value.raw());
}


void Function::set_context_scope(const ContextScope& value) const {
  StorePointer(&raw_ptr()->context_scope_, value.raw());
}


void Function::set_closure_allocation_stub(const Code& value) const {
  ASSERT(!value.IsNull());
  ASSERT(raw_ptr()->closure_allocation_stub_ == Code::null());
  StorePointer(&raw_ptr()->closure_allocation_stub_, value.raw());
}


void Function::set_implicit_closure_function(const Function& value) const {
  ASSERT(!value.IsNull());
  ASSERT(raw_ptr()->implicit_closure_function_ == Function::null());
  StorePointer(&raw_ptr()->implicit_closure_function_, value.raw());
}


void Function::set_parent_function(const Function& value) const {
  StorePointer(&raw_ptr()->parent_function_, value.raw());
}


void Function::set_signature_class(const Class& value) const {
  StorePointer(&raw_ptr()->signature_class_, value.raw());
}


bool Function::IsInFactoryScope() const {
  Function& outer_function = Function::Handle(raw());
  while (outer_function.IsLocalFunction()) {
    outer_function = outer_function.parent_function();
  }
  return outer_function.IsFactory();
}


void Function::set_name(const String& value) const {
  ASSERT(value.IsSymbol());
  StorePointer(&raw_ptr()->name_, value.raw());
}


void Function::set_owner(const Class& value) const {
  ASSERT(!value.IsNull());
  StorePointer(&raw_ptr()->owner_, value.raw());
}


void Function::set_result_type(const AbstractType& value) const {
  ASSERT(!value.IsNull());
  StorePointer(&raw_ptr()->result_type_, value.raw());
}


RawAbstractType* Function::ParameterTypeAt(intptr_t index) const {
  const Array& parameter_types = Array::Handle(raw_ptr()->parameter_types_);
  AbstractType& parameter_type = AbstractType::Handle();
  parameter_type ^= parameter_types.At(index);
  return parameter_type.raw();
}


void Function::SetParameterTypeAt(
    intptr_t index, const AbstractType& value) const {
  ASSERT(!value.IsNull());
  const Array& parameter_types = Array::Handle(raw_ptr()->parameter_types_);
  parameter_types.SetAt(index, value);
}


void Function::set_parameter_types(const Array& value) const {
  StorePointer(&raw_ptr()->parameter_types_, value.raw());
}


RawString* Function::ParameterNameAt(intptr_t index) const {
  const Array& parameter_names = Array::Handle(raw_ptr()->parameter_names_);
  String& parameter_name = String::Handle();
  parameter_name ^= parameter_names.At(index);
  return parameter_name.raw();
}


void Function::SetParameterNameAt(intptr_t index, const String& value) const {
  ASSERT(!value.IsNull() && value.IsSymbol());
  const Array& parameter_names = Array::Handle(raw_ptr()->parameter_names_);
  parameter_names.SetAt(index, value);
}


void Function::set_parameter_names(const Array& value) const {
  StorePointer(&raw_ptr()->parameter_names_, value.raw());
}


void Function::set_kind(RawFunction::Kind value) const {
  raw_ptr()->kind_ = value;
}


void Function::set_is_static(bool is_static) const {
  raw_ptr()->is_static_ = is_static;
}


void Function::set_is_const(bool is_const) const {
  raw_ptr()->is_const_ = is_const;
}


void Function::set_token_index(intptr_t pos) const {
  ASSERT(pos >= 0);
  raw_ptr()->token_index_ = pos;
}


void Function::set_num_fixed_parameters(intptr_t n) const {
  ASSERT(n >= 0);
  raw_ptr()->num_fixed_parameters_ = n;
}


void Function::set_num_optional_parameters(intptr_t n) const {
  ASSERT(n >= 0);
  raw_ptr()->num_optional_parameters_ = n;
}


void Function::set_is_optimizable(bool value) const {
  raw_ptr()->is_optimizable_ = value;
}


intptr_t Function::NumberOfParameters() const {
  return num_fixed_parameters() + num_optional_parameters();
}


bool Function::AreValidArgumentCounts(int num_arguments,
                                      int num_named_arguments) const {
  if (num_arguments > NumberOfParameters()) {
    return false;  // Too many arguments.
  }
  const int num_positional_args = num_arguments - num_named_arguments;
  if (num_positional_args < num_fixed_parameters()) {
    return false;  // Too few arguments.
  }
  return true;
}


// TODO(regis): Return some sort of diagnosis information so that we
// can improve the error messages generated by the parser.
bool Function::AreValidArguments(int num_arguments,
                                 const Array& argument_names) const {
  const int num_named_arguments =
      argument_names.IsNull() ? 0 : argument_names.Length();
  if (!AreValidArgumentCounts(num_arguments, num_named_arguments)) {
    return false;
  }
  // Verify that all argument names are valid parameter names.
  String& argument_name = String::Handle();
  String& parameter_name = String::Handle();
  for (int i = 0; i < num_named_arguments; i++) {
    argument_name ^= argument_names.At(i);
    ASSERT(argument_name.IsSymbol());
    bool found = false;
    const int num_positional_args = num_arguments - num_named_arguments;
    const int num_parameters = NumberOfParameters();
    for (int j = num_positional_args; !found && (j < num_parameters); j++) {
      parameter_name ^= ParameterNameAt(j);
      ASSERT(argument_name.IsSymbol());
      if (argument_name.Equals(parameter_name)) {
        found = true;
      }
    }
    if (!found) {
      return false;
    }
  }
  return true;
}


// Helper allocating a C string buffer in the zone, printing the fully qualified
// name of a function in it, and replacing ':' by '_' to make sure the
// constructed name is a valid C++ identifier for debugging purpose.
// Set 'chars' to allocated buffer and return number of written characters.
static intptr_t ConstructFunctionFullyQualifiedCString(const Function& function,
                                                       char** chars,
                                                       intptr_t reserve_len) {
  const char* name = String::Handle(function.name()).ToCString();
  const char* function_format = (reserve_len == 0) ? "%s" : "%s_";
  reserve_len += OS::SNPrint(NULL, 0, function_format, name);
  const Function& parent = Function::Handle(function.parent_function());
  intptr_t written = 0;
  if (parent.IsNull()) {
    const Class& function_class = Class::Handle(function.owner());
    ASSERT(!function_class.IsNull());
    const char* class_name = String::Handle(function_class.Name()).ToCString();
    ASSERT(class_name != NULL);
    const Library& library = Library::Handle(function_class.library());
    ASSERT(!library.IsNull());
    const char* library_name = String::Handle(library.url()).ToCString();
    ASSERT(library_name != NULL);
    const char* lib_class_format =
        (library_name[0] == '\0') ? "%s%s_" : "%s_%s_";
    reserve_len +=
        OS::SNPrint(NULL, 0, lib_class_format, library_name, class_name);
    ASSERT(chars != NULL);
    *chars = reinterpret_cast<char*>(
        Isolate::Current()->current_zone()->Allocate(reserve_len + 1));
    written = OS::SNPrint(
        *chars, reserve_len, lib_class_format, library_name, class_name);
  } else {
    written = ConstructFunctionFullyQualifiedCString(parent,
                                                     chars,
                                                     reserve_len);
  }
  ASSERT(*chars != NULL);
  char* next = *chars + written;
  written += OS::SNPrint(next, reserve_len + 1, function_format, name);
  // Replace ":" with "_".
  while (true) {
    next = strchr(next, ':');
    if (next == NULL) break;
    *next = '_';
  }
  return written;
}


const char* Function::ToFullyQualifiedCString() const {
  char* chars = NULL;
  ConstructFunctionFullyQualifiedCString(*this, &chars, 0);
  return chars;
}


bool Function::HasCompatibleParametersWith(const Function& other) const {
  // The default values of optional parameters can differ.
  const intptr_t num_fixed_params = num_fixed_parameters();
  const intptr_t num_opt_params = num_optional_parameters();
  const intptr_t other_num_fixed_params = other.num_fixed_parameters();
  const intptr_t other_num_opt_params = other.num_optional_parameters();
  if ((num_fixed_params != other_num_fixed_params) ||
      (num_opt_params < other_num_opt_params)) {
    return false;
  }
  // Check that for each optional named parameter of the other function there is
  // a corresponding optional named parameter of this function with an identical
  // name at the same position.
  // Note that SetParameterNameAt() guarantees that names are symbols, so we can
  // compare their raw pointers.
  const int other_num_params = other_num_fixed_params + other_num_opt_params;
  for (intptr_t i = other_num_fixed_params; i < other_num_params; i++) {
    const String& other_param_name = String::Handle(other.ParameterNameAt(i));
    if (ParameterNameAt(i) != other_param_name.raw()) {
      return false;
    }
  }
  return true;
}


bool Function::TestParameterType(
    intptr_t parameter_position,
    const AbstractTypeArguments& type_arguments,
    const Function& other,
    const AbstractTypeArguments& other_type_arguments,
    Error* malformed_error) const {
  AbstractType& param_type =
      AbstractType::Handle(ParameterTypeAt(parameter_position));
  if (!param_type.IsInstantiated()) {
    param_type = param_type.InstantiateFrom(type_arguments);
  }
  if (param_type.IsDynamicType()) {
    return true;
  }
  AbstractType& other_param_type =
      AbstractType::Handle(other.ParameterTypeAt(parameter_position));
  if (!other_param_type.IsInstantiated()) {
    other_param_type = other_param_type.InstantiateFrom(other_type_arguments);
  }
  if (other_param_type.IsDynamicType()) {
    return true;
  }
  if (!param_type.IsSubtypeOf(other_param_type, malformed_error) &&
      !other_param_type.IsSubtypeOf(param_type, malformed_error)) {
    return false;
  }
  return true;
}


bool Function::IsSubtypeOf(
    const AbstractTypeArguments& type_arguments,
    const Function& other,
    const AbstractTypeArguments& other_type_arguments,
    Error* malformed_error) const {
  const intptr_t num_fixed_params = num_fixed_parameters();
  const intptr_t num_opt_params = num_optional_parameters();
  const intptr_t other_num_fixed_params = other.num_fixed_parameters();
  const intptr_t other_num_opt_params = other.num_optional_parameters();
  if ((num_fixed_params != other_num_fixed_params) ||
      (num_opt_params < other_num_opt_params)) {
    return false;
  }
  // Check the result type.
  AbstractType& other_res_type = AbstractType::Handle(other.result_type());
  if (!other_res_type.IsInstantiated()) {
    other_res_type = other_res_type.InstantiateFrom(other_type_arguments);
  }
  if (!other_res_type.IsDynamicType() && !other_res_type.IsVoidType()) {
    AbstractType& res_type = AbstractType::Handle(result_type());
    if (!res_type.IsInstantiated()) {
      res_type = res_type.InstantiateFrom(type_arguments);
    }
    if (!res_type.IsDynamicType() &&
        (res_type.IsVoidType() ||
         !(res_type.IsSubtypeOf(other_res_type, malformed_error) ||
           other_res_type.IsSubtypeOf(res_type, malformed_error)))) {
      return false;
    }
  }
  // Check the types of fixed parameters.
  for (intptr_t i = 0; i < num_fixed_params; i++) {
    if (!TestParameterType(i, type_arguments, other, other_type_arguments,
                           malformed_error)) {
      return false;
    }
  }
  // Check the names and types of optional parameters.
  // Check that for each optional named parameter of type T of the other
  // function type, there is a corresponding optional named parameter of this
  // function at the same position with an identical name and with a type S
  // that is a subtype or supertype of T.
  // Note that SetParameterNameAt() guarantees that names are symbols, so we
  // can compare their raw pointers.
  const intptr_t other_num_params =
      other_num_fixed_params + other_num_opt_params;
  String& other_param_name = String::Handle();
  for (intptr_t i = other_num_fixed_params; i < other_num_params; i++) {
    other_param_name = other.ParameterNameAt(i);
    if ((ParameterNameAt(i) != other_param_name.raw()) ||
        !TestParameterType(i, type_arguments, other, other_type_arguments,
                           malformed_error)) {
      return false;
    }
  }
  return true;
}


bool Function::IsImplicitClosureFunction() const {
  if (!IsClosureFunction()) {
    return false;
  }
  const Function& parent = Function::Handle(parent_function());
  return parent.raw_ptr()->implicit_closure_function_ == raw();
}


RawFunction* Function::New() {
  const Class& function_class = Class::Handle(Object::function_class());
  RawObject* raw = Object::Allocate(function_class,
                                    Function::InstanceSize(),
                                    Heap::kOld);
  return reinterpret_cast<RawFunction*>(raw);
}


RawFunction* Function::New(const String& name,
                           RawFunction::Kind kind,
                           bool is_static,
                           bool is_const,
                           intptr_t token_index) {
  const Function& result = Function::Handle(Function::New());
  result.set_parameter_types(Array::Handle(Array::Empty()));
  result.set_parameter_names(Array::Handle(Array::Empty()));
  result.set_name(name);
  result.set_kind(kind);
  result.set_is_static(is_static);
  result.set_is_const(is_const);
  result.set_token_index(token_index);
  result.set_end_token_index(token_index);
  result.set_num_fixed_parameters(0);
  result.set_num_optional_parameters(0);
  result.set_usage_counter(0);
  result.set_deoptimization_counter(0);
  result.set_is_optimizable(true);
  return result.raw();
}


RawFunction* Function::NewClosureFunction(const String& name,
                                          const Function& parent,
                                          intptr_t token_index) {
  ASSERT(!parent.IsNull());
  const Class& parent_class = Class::Handle(parent.owner());
  ASSERT(!parent_class.IsNull());
  const Function& result = Function::Handle(
      Function::New(name,
                    RawFunction::kClosureFunction,
                    /* is_static = */ parent.is_static(),
                    /* is_const = */ false,
                    token_index));
  result.set_parent_function(parent);
  result.set_owner(parent_class);
  return result.raw();
}


RawFunction* Function::ImplicitClosureFunction() const {
  // Return the existing implicit closure function if any.
  if (raw_ptr()->implicit_closure_function_ != Function::null()) {
    return raw_ptr()->implicit_closure_function_;
  }
  ASSERT(!IsSignatureFunction() && !IsClosureFunction());
  // Create closure function.
  const String& closure_name = String::Handle(name());
  const Function& closure_function = Function::Handle(
      NewClosureFunction(closure_name, *this, token_index()));

  // Set closure function's context scope.
  ContextScope& context_scope = ContextScope::Handle();
  if (is_static()) {
    context_scope ^= ContextScope::New(0);
  } else {
    context_scope ^= LocalScope::CreateImplicitClosureScope(*this);
  }
  closure_function.set_context_scope(context_scope);

  // Set closure function's result type to this result type.
  closure_function.set_result_type(AbstractType::Handle(result_type()));

  // Set closure function's formal parameters to this formal parameters,
  // removing the receiver if this is an instance method.
  const int has_receiver = is_static() ? 0 : 1;
  const int num_fixed_params = num_fixed_parameters() - has_receiver;
  const int num_optional_params = num_optional_parameters();
  const int num_params = num_fixed_params + num_optional_params;
  closure_function.set_num_fixed_parameters(num_fixed_params);
  closure_function.set_num_optional_parameters(num_optional_params);
  closure_function.set_parameter_types(Array::Handle(Array::New(num_params,
                                                                Heap::kOld)));
  closure_function.set_parameter_names(Array::Handle(Array::New(num_params,
                                                                Heap::kOld)));
  AbstractType& param_type = AbstractType::Handle();
  String& param_name = String::Handle();
  for (int i = 0; i < num_params; i++) {
    param_type = ParameterTypeAt(i + has_receiver);
    closure_function.SetParameterTypeAt(i, param_type);
    param_name = ParameterNameAt(i + has_receiver);
    closure_function.SetParameterNameAt(i, param_name);
  }

  // Lookup or create a new signature class for the closure function in the
  // library of the owner class.
  const Class& owner_class = Class::Handle(owner());
  ASSERT(!owner_class.IsNull() && (owner() == closure_function.owner()));
  const Library& library = Library::Handle(owner_class.library());
  ASSERT(!library.IsNull());
  const String& signature = String::Handle(closure_function.Signature());
  Class& signature_class = Class::ZoneHandle(
      library.LookupLocalClass(signature));
  if (signature_class.IsNull()) {
    const Script& script = Script::Handle(owner_class.script());
    signature_class = Class::NewSignatureClass(signature,
                                               closure_function,
                                               script);
    library.AddClass(signature_class);
  } else {
    closure_function.set_signature_class(signature_class);
  }
  const Type& signature_type = Type::Handle(signature_class.SignatureType());
  if (!signature_type.IsFinalized()) {
    ClassFinalizer::FinalizeType(
        signature_class, signature_type, ClassFinalizer::kFinalize);
  }
  ASSERT(closure_function.signature_class() == signature_class.raw());
  set_implicit_closure_function(closure_function);
  ASSERT(closure_function.IsImplicitClosureFunction());
  return closure_function.raw();
}


RawString* Function::BuildSignature(
    bool instantiate,
    const AbstractTypeArguments& instantiator) const {
  const GrowableObjectArray& pieces =
      GrowableObjectArray::Handle(GrowableObjectArray::New());
  const String& kCommaSpace = String::Handle(String::NewSymbol(", "));
  const String& kColonSpace = String::Handle(String::NewSymbol(": "));
  const String& kLParen = String::Handle(String::NewSymbol("("));
  const String& kRParen = String::Handle(String::NewSymbol(") => "));
  const String& kLBracket = String::Handle(String::NewSymbol("["));
  const String& kRBracket = String::Handle(String::NewSymbol("]"));
  String& name = String::Handle();
  if (!instantiate && !is_static()) {
    const String& kSpaceExtendsSpace =
        String::Handle(String::NewSymbol(" extends "));
    const String& kLAngleBracket = String::Handle(String::NewSymbol("<"));
    const String& kRAngleBracket = String::Handle(String::NewSymbol(">"));
    const Class& function_class = Class::Handle(owner());
    ASSERT(!function_class.IsNull());
    const TypeArguments& type_parameters = TypeArguments::Handle(
        function_class.type_parameters());
    if (!type_parameters.IsNull()) {
      intptr_t num_type_parameters = type_parameters.Length();
      pieces.Add(kLAngleBracket);
      const TypeArguments& bounds = TypeArguments::Handle(
          function_class.type_parameter_bounds());
      AbstractType& type_parameter = AbstractType::Handle();
      AbstractType& bound = AbstractType::Handle();
      for (intptr_t i = 0; i < num_type_parameters; i++) {
        type_parameter ^= type_parameters.TypeAt(i);
        name = type_parameter.Name();
        pieces.Add(name);
        bound = bounds.TypeAt(i);
        if (!bound.IsNull() && !bound.IsDynamicType()) {
          pieces.Add(kSpaceExtendsSpace);
          name = bound.Name();
          pieces.Add(name);
        }
        if (i < num_type_parameters - 1) {
          pieces.Add(kCommaSpace);
        }
      }
      pieces.Add(kRAngleBracket);
    }
  }
  AbstractType& param_type = AbstractType::Handle();
  const intptr_t num_params = NumberOfParameters();
  const intptr_t num_fixed_params = num_fixed_parameters();
  const intptr_t num_opt_params = num_optional_parameters();
  ASSERT((num_fixed_params + num_opt_params) == num_params);
  pieces.Add(kLParen);
  for (intptr_t i = 0; i < num_fixed_params; i++) {
    param_type = ParameterTypeAt(i);
    ASSERT(!param_type.IsNull());
    if (instantiate && !param_type.IsInstantiated()) {
      param_type = param_type.InstantiateFrom(instantiator);
    }
    name = param_type.Name();
    pieces.Add(name);
    if (i != (num_params - 1)) {
      pieces.Add(kCommaSpace);
    }
  }
  if (num_opt_params > 0) {
    pieces.Add(kLBracket);
    for (intptr_t i = num_fixed_params; i < num_params; i++) {
      name = ParameterNameAt(i);
      pieces.Add(name);
      pieces.Add(kColonSpace);
      param_type = ParameterTypeAt(i);
      if (instantiate && !param_type.IsInstantiated()) {
        param_type = param_type.InstantiateFrom(instantiator);
      }
      ASSERT(!param_type.IsNull());
      name = param_type.Name();
      pieces.Add(name);
      if (i != (num_params - 1)) {
        pieces.Add(kCommaSpace);
      }
    }
    pieces.Add(kRBracket);
  }
  pieces.Add(kRParen);
  AbstractType& res_type = AbstractType::Handle(result_type());
  if (instantiate && !res_type.IsInstantiated()) {
    res_type = res_type.InstantiateFrom(instantiator);
  }
  name = res_type.Name();
  pieces.Add(name);
  const Array& strings = Array::Handle(Array::MakeArray(pieces));
  return String::NewSymbol(String::Handle(String::ConcatAll(strings)));
}


bool Function::HasInstantiatedSignature() const {
  AbstractType& type = AbstractType::Handle(result_type());
  if (!type.IsInstantiated()) {
    return false;
  }
  const intptr_t num_parameters = NumberOfParameters();
  for (intptr_t i = 0; i < num_parameters; i++) {
    type = ParameterTypeAt(i);
    if (!type.IsInstantiated()) {
      return false;
    }
  }
  return true;
}


bool Function::HasOptimizedCode() const {
  return HasCode() && Code::Handle(raw_ptr()->code_).is_optimized();
}


const char* Function::ToCString() const {
  const char* f0 = is_static() ? " static" : "";
  const char* f1 = NULL;
  const char* f2 = is_const() ? " const" : "";
  switch (kind()) {
    case RawFunction::kFunction:
    case RawFunction::kClosureFunction:
    case RawFunction::kGetterFunction:
    case RawFunction::kSetterFunction:
      f1 = "";
      break;
    case RawFunction::kSignatureFunction:
      f1 = " signature";
      break;
    case RawFunction::kAbstract:
      f1 = " abstract";
      break;
    case RawFunction::kConstructor:
      f1 = is_static() ? " factory" : " constructor";
      break;
    case RawFunction::kImplicitGetter:
      f1 = " getter";
      break;
    case RawFunction::kImplicitSetter:
      f1 = " setter";
      break;
    case RawFunction::kConstImplicitGetter:
      f1 = " const-getter";
      break;
    default:
      UNREACHABLE();
  }
  const char* kFormat = "Function '%s':%s%s%s.";
  const char* function_name = String::Handle(name()).ToCString();
  intptr_t len = OS::SNPrint(NULL, 0, kFormat, function_name, f0, f1, f2) + 1;
  char* chars = reinterpret_cast<char*>(
      Isolate::Current()->current_zone()->Allocate(len));
  OS::SNPrint(chars, len, kFormat, function_name, f0, f1, f2);
  return chars;
}


RawString* Field::GetterName(const String& field_name) {
  String& str = String::Handle();
  str = String::New(kGetterPrefix);
  str = String::Concat(str, field_name);
  return str.raw();
}


RawString* Field::GetterSymbol(const String& field_name) {
  String& str = String::Handle();
  str = Field::GetterName(field_name);
  return String::NewSymbol(str);
}


RawString* Field::SetterName(const String& field_name) {
  String& str = String::Handle();
  str = String::New(kSetterPrefix);
  str = String::Concat(str, field_name);
  return str.raw();
}


RawString* Field::SetterSymbol(const String& field_name) {
  String& str = String::Handle();
  str = Field::SetterName(field_name);
  return String::NewSymbol(str);
}


RawString* Field::NameFromGetter(const String& getter_name) {
  String& str = String::Handle();
  str = String::New(kGetterPrefix);
  str = String::SubString(getter_name, str.Length());
  return str.raw();
}


RawString* Field::NameFromSetter(const String& setter_name) {
  String& str = String::Handle();
  str = String::New(kSetterPrefix);
  str = String::SubString(setter_name, str.Length());
  return str.raw();
}


void Field::set_name(const String& value) const {
  ASSERT(value.IsSymbol());
  StorePointer(&raw_ptr()->name_, value.raw());
}


RawInstance* Field::value() const {
  ASSERT(is_static());  // Valid only for static dart fields.
  return raw_ptr()->value_;
}


void Field::set_value(const Instance& value) const {
  ASSERT(is_static());  // Valid only for static dart fields.
  StorePointer(&raw_ptr()->value_, value.raw());
}


void Field::set_type(const AbstractType& value) const {
  ASSERT(!value.IsNull());
  StorePointer(&raw_ptr()->type_, value.raw());
}


RawField* Field::New() {
  const Class& field_class = Class::Handle(Object::field_class());
  RawObject* raw = Object::Allocate(field_class,
                                    Field::InstanceSize(),
                                    Heap::kOld);
  return reinterpret_cast<RawField*>(raw);
}


RawField* Field::New(const String& name,
                     bool is_static,
                     bool is_final,
                     intptr_t token_index) {
  const Field& result = Field::Handle(Field::New());
  result.set_name(name);
  result.set_is_static(is_static);
  if (is_static) {
    result.set_value(Instance::Handle());
  } else {
    result.SetOffset(0);
  }
  result.set_is_final(is_final);
  result.set_token_index(token_index);
  result.set_has_initializer(false);
  return result.raw();
}


const char* Field::ToCString() const {
  const char* kF0 = is_static() ? " static" : "";
  const char* kF1 = is_final() ? " final" : "";
  const char* kFormat = "Field <%s.%s>:%s%s";
  const char* field_name = String::Handle(name()).ToCString();
  const Class& cls = Class::Handle(owner());
  const char* cls_name = String::Handle(cls.Name()).ToCString();
  intptr_t len =
      OS::SNPrint(NULL, 0, kFormat, cls_name, field_name, kF0, kF1) + 1;
  char* chars = reinterpret_cast<char*>(
      Isolate::Current()->current_zone()->Allocate(len));
  OS::SNPrint(chars, len, kFormat, cls_name, field_name, kF0, kF1);
  return chars;
}


void LiteralToken::set_literal(const String& literal) const {
  StorePointer(&raw_ptr()->literal_, literal.raw());
}


void LiteralToken::set_value(const Object& value) const {
  StorePointer(&raw_ptr()->value_, value.raw());
}


RawLiteralToken* LiteralToken::New() {
  const Class& cls = Class::Handle(Object::literal_token_class());
  RawObject* raw = Object::Allocate(cls,
                                    LiteralToken::InstanceSize(),
                                    Heap::kOld);
  return reinterpret_cast<RawLiteralToken*>(raw);
}


RawLiteralToken* LiteralToken::New(Token::Kind kind, const String& literal) {
  const LiteralToken& result = LiteralToken::Handle(LiteralToken::New());
  result.set_kind(kind);
  result.set_literal(literal);
  if (kind == Token::kINTEGER) {
    const Integer& value = Integer::Handle(Integer::New(literal));
    result.set_value(value);
  } else if (kind == Token::kDOUBLE) {
    const Double& value = Double::Handle(Double::NewCanonical(literal));
    result.set_value(value);
  } else {
    ASSERT(Token::NeedsLiteralToken(kind));
    result.set_value(literal);
  }
  return result.raw();
}


const char* LiteralToken::ToCString() const {
  const String& token = String::Handle(literal());
  return token.ToCString();
}


void TokenStream::SetLength(intptr_t value) const {
  raw_ptr()->length_ = Smi::New(value);
}


void TokenStream::SetTokenAt(intptr_t index,
                             Token::Kind kind,
                             const String& literal) {
  if (kind == Token::kIDENT) {
    if (FLAG_compiler_stats) {
      CompilerStats::num_ident_tokens_total += 1;
    }
    StorePointer(EntryAddr(index), reinterpret_cast<RawObject*>(literal.raw()));
  } else if (Token::NeedsLiteralToken(kind)) {
    if (FLAG_compiler_stats) {
      CompilerStats::num_literal_tokens_total += 1;
    }
    StorePointer(
        EntryAddr(index),
        reinterpret_cast<RawObject*>(LiteralToken::New(kind, literal)));
  } else {
    ASSERT(kind < Token::kNumTokens);
    *(SmiAddr(index)) = Smi::New(kind);
  }
}


void TokenStream::SetTokenAt(intptr_t index, const Object& token) {
  StorePointer(EntryAddr(index), token.raw());
}


RawObject* TokenStream::TokenAt(intptr_t index) const {
  return *EntryAddr(index);
}


RawString* TokenStream::LiteralAt(intptr_t index) const {
  const Object& obj = Object::Handle(TokenAt(index));
  if (obj.IsString()) {
    return reinterpret_cast<RawString*>(obj.raw());
  } else if (obj.IsSmi()) {
    Token::Kind kind = static_cast<Token::Kind>(
        Smi::Value(reinterpret_cast<RawSmi*>(obj.raw())));
    ASSERT(kind < Token::kNumTokens);
    if (Token::IsPseudoKeyword(kind) || Token::IsKeyword(kind)) {
      Isolate* isolate = Isolate::Current();
      ObjectStore* object_store = isolate->object_store();
      String& str = String::Handle(isolate, String::null());
      const Array& symbols = Array::Handle(isolate,
                                           object_store->keyword_symbols());
      ASSERT(!symbols.IsNull());
      str ^= symbols.At(kind - Token::kFirstKeyword);
      ASSERT(!str.IsNull());
      return str.raw();
    }
    return String::NewSymbol(Token::Str(kind));
  } else {
    LiteralToken& token = LiteralToken::Handle();
    token ^= obj.raw();  // Must be a literal token.
    return token.literal();
  }
}


RawTokenStream* TokenStream::New(intptr_t len) {
  const Class& token_stream_class = Class::Handle(Object::token_stream_class());
  TokenStream& result = TokenStream::Handle();
  {
    RawObject* raw = Object::Allocate(token_stream_class,
                                      TokenStream::InstanceSize(len),
                                      Heap::kOld);
    NoGCScope no_gc;
    result ^= raw;
    result.SetLength(len);
  }
  return result.raw();
}


RawTokenStream* TokenStream::New(const Scanner::GrowableTokenStream& tokens) {
  intptr_t len = tokens.length();

  TokenStream& result = TokenStream::Handle(New(len));
  // Copy the relevant data out of the scanner's token stream.
  const String& empty_literal = String::Handle();
  for (intptr_t i = 0; i < len; i++) {
    Scanner::TokenDescriptor token = tokens[i];
    if (token.literal != NULL) {
      result.SetTokenAt(i, token.kind, *(token.literal));
    } else {
      result.SetTokenAt(i, token.kind, empty_literal);
    }
  }
  return result.raw();
}


const char* TokenStream::ToCString() const {
  return "TokenStream";
}


void Script::set_url(const String& value) const {
  StorePointer(&raw_ptr()->url_, value.raw());
}


void Script::set_source(const String& value) const {
  StorePointer(&raw_ptr()->source_, value.raw());
}


void Script::set_kind(RawScript::Kind value) const {
  raw_ptr()->kind_ = value;
}


void Script::set_tokens(const TokenStream& value) const {
  StorePointer(&raw_ptr()->tokens_, value.raw());
}


void Script::Tokenize(const String& private_key) const {
  const TokenStream& tkns = TokenStream::Handle(tokens());
  if (!tkns.IsNull()) {
    // Already tokenized.
    return;
  }

  // Get the source, scan and allocate the token stream.
  TimerScope timer(FLAG_compiler_stats, &CompilerStats::scanner_timer);
  const String& src = String::Handle(source());
  Scanner scanner(src, private_key);
  set_tokens(TokenStream::Handle(TokenStream::New(scanner.GetStream())));
  if (FLAG_compiler_stats) {
    CompilerStats::src_length += src.Length();
  }
}


void Script::GetTokenLocation(intptr_t token_index,
                              intptr_t* line,
                              intptr_t* column) const {
  const String& src = String::Handle(source());
  const String& dummy_key = String::Handle(String::New(""));
  Scanner scanner(src, dummy_key);
  scanner.ScanTo(token_index);
  *line = scanner.CurrentPosition().line;
  *column = scanner.CurrentPosition().column;
}


intptr_t Script::TokenIndexAtLine(intptr_t line_number) const {
  const String& src = String::Handle(source());
  const String& dummy_key = String::Handle(String::New(""));
  Scanner scanner(src, dummy_key);
  return scanner.TokenIndexAtLine(line_number);
}


RawString* Script::GetLine(intptr_t line_number) const {
  const String& src = String::Handle(source());
  intptr_t current_line = 1;
  intptr_t line_start = -1;
  intptr_t last_char = -1;
  for (intptr_t ix = 0;
       (ix < src.Length()) && (current_line <= line_number);
       ix++) {
    if ((current_line == line_number) && (line_start < 0)) {
      line_start = ix;
    }
    if (src.CharAt(ix) == '\n') {
      current_line++;
    } else if (src.CharAt(ix) == '\r') {
      if ((ix + 1 != src.Length()) && (src.CharAt(ix + 1) != '\n')) {
        current_line++;
      }
    } else {
      last_char = ix;
    }
  }
  // Guarantee that returned string is never NULL.
  String& line = String::Handle(String::NewSymbol(""));
  if (line_start >= 0) {
    line = String::SubString(src, line_start, last_char - line_start + 1);
  }
  return line.raw();
}


RawString* Script::GetSnippet(intptr_t from_line,
                              intptr_t from_column,
                              intptr_t to_line,
                              intptr_t to_column) const {
  const String& src = String::Handle(source());
  intptr_t length = src.Length();
  intptr_t line = 1;
  intptr_t column = 1;
  intptr_t lookahead = 0;
  intptr_t snippet_start = -1;
  intptr_t snippet_end = -1;
  char c = src.CharAt(lookahead);
  while (lookahead != length) {
    if (snippet_start == -1) {
      if ((line == from_line) && (column == from_column)) {
        snippet_start = lookahead;
      }
    } else if ((line == to_line) && (column == to_column)) {
      snippet_end = lookahead;
      break;
    }
    if (c == '\n') {
      line++;
      column = 0;
    }
    column++;
    lookahead++;
    if (lookahead != length) {
      // Replace '\r' with '\n' and a sequence of '\r' '\n' with a single '\n'.
      if (src.CharAt(lookahead) == '\r') {
        c = '\n';
        if (lookahead + 1 != length && src.CharAt(lookahead) == '\n') {
          lookahead++;
        }
      } else {
        c = src.CharAt(lookahead);
      }
    }
  }
  String& snippet = String::Handle();
  if ((snippet_start != -1) && (snippet_end != -1)) {
    snippet =
        String::SubString(src, snippet_start, snippet_end - snippet_start);
  }
  return snippet.raw();
}


RawScript* Script::New() {
  const Class& script_class = Class::Handle(Object::script_class());
  RawObject* raw = Object::Allocate(script_class,
                                    Script::InstanceSize(),
                                    Heap::kOld);
  return reinterpret_cast<RawScript*>(raw);
}


RawScript* Script::New(const String& url,
                       const String& source,
                       RawScript::Kind kind) {
  const Script& result = Script::Handle(Script::New());
  result.set_url(String::Handle(String::NewSymbol(url)));
  result.set_source(source);
  result.set_kind(kind);
  return result.raw();
}


const char* Script::ToCString() const {
  return "Script";
}


DictionaryIterator::DictionaryIterator(const Library& library)
    : array_(Array::Handle(library.dictionary())),
      // Last element in array is a Smi.
      size_(Array::Handle(library.dictionary()).Length() - 1),
      next_ix_(0) {
  MoveToNextObject();
}


RawObject* DictionaryIterator::GetNext() {
  ASSERT(HasNext());
  int ix = next_ix_++;
  MoveToNextObject();
  ASSERT(array_.At(ix) != Object::null());
  return array_.At(ix);
}


void DictionaryIterator::MoveToNextObject() {
  Object& obj = Object::Handle(array_.At(next_ix_));
  while (obj.IsNull() && HasNext()) {
    next_ix_++;
    obj = array_.At(next_ix_);
  }
}


ClassDictionaryIterator::ClassDictionaryIterator(const Library& library)
    : DictionaryIterator(library) {
  MoveToNextClass();
}


RawClass* ClassDictionaryIterator::GetNextClass() {
  ASSERT(HasNext());
  int ix = next_ix_++;
  Object& obj = Object::Handle(array_.At(ix));
  MoveToNextClass();
  Class& cls = Class::Handle();
  cls ^= obj.raw();
  return cls.raw();
}


void ClassDictionaryIterator::MoveToNextClass() {
  Object& obj = Object::Handle(array_.At(next_ix_));
  while (!obj.IsClass() && HasNext()) {
    next_ix_++;
    obj = array_.At(next_ix_);
  }
}


void Library::set_import_map(const Array& map) const {
  StorePointer(&raw_ptr()->import_map_, map.raw());
}


void Library::SetName(const String& name) const {
  // Only set name once.
  ASSERT(!Loaded());
  ASSERT(name.IsSymbol());
  StorePointer(&raw_ptr()->name_, name.raw());
}


void Library::SetLoadInProgress() const {
  // Should not be already loaded.
  ASSERT(raw_ptr()->load_state_ == RawLibrary::kAllocated);
  raw_ptr()->load_state_ = RawLibrary::kLoadInProgress;
}


void Library::SetLoaded() const {
  // Should not be already loaded or just allocated.
  ASSERT(LoadInProgress());
  raw_ptr()->load_state_ = RawLibrary::kLoaded;
}


void Library::SetLoadError() const {
  // Should not be already loaded or just allocated.
  ASSERT(LoadInProgress());
  raw_ptr()->load_state_ = RawLibrary::kLoadError;
}


void Library::GrowDictionary(const Array& dict, intptr_t dict_size) const {
  // TODO(iposva): Avoid exponential growth.
  intptr_t new_dict_size = dict_size * 2;
  const Array& new_dict =
      Array::Handle(Array::New(new_dict_size + 1, Heap::kOld));
  // Rehash all elements from the original dictionary
  // to the newly allocated array.
  Object& entry = Class::Handle();
  String& entry_name = String::Handle();
  Object& new_entry = Object::Handle();
  Class& cls = Class::Handle();
  Function& func = Function::Handle();
  Field& field = Field::Handle();
  LibraryPrefix& prefix = LibraryPrefix::Handle();
  for (intptr_t i = 0; i < dict_size; i++) {
    entry = dict.At(i);
    if (!entry.IsNull()) {
      if (entry.IsClass()) {
        cls ^= entry.raw();
        entry_name = cls.Name();
      } else if (entry.IsFunction()) {
        func ^= entry.raw();
        entry_name = func.name();
      } else if (entry.IsField()) {
        field ^= entry.raw();
        entry_name = field.name();
      } else if (entry.IsLibraryPrefix()) {
        prefix ^= entry.raw();
        entry_name = prefix.name();
      } else {
        UNREACHABLE();
      }
      intptr_t hash = entry_name.Hash();
      intptr_t index = hash % new_dict_size;
      new_entry = new_dict.At(index);
      while (!new_entry.IsNull()) {
        index = (index + 1) % new_dict_size;  // Move to next element.
        new_entry = new_dict.At(index);
      }
      new_dict.SetAt(index, entry);
    }
  }
  // Copy used count.
  new_entry = dict.At(dict_size);
  new_dict.SetAt(new_dict_size, new_entry);
  // Remember the new dictionary now.
  StorePointer(&raw_ptr()->dictionary_, new_dict.raw());
}


void Library::AddObject(const Object& obj, const String& name) const {
  ASSERT(obj.IsClass() ||
         obj.IsFunction() ||
         obj.IsField() ||
         obj.IsLibraryPrefix());
  ASSERT((LookupObject(name) == Object::null()) ||
         ((obj.IsLibraryPrefix() ||
           (obj.IsClass() &&
            Class::CheckedHandle(obj.raw()).IsCanonicalSignatureClass())) &&
          (LookupLocalObject(name) == Object::null())));
  const Array& dict = Array::Handle(dictionary());
  intptr_t dict_size = dict.Length() - 1;
  intptr_t index = name.Hash() % dict_size;

  Object& entry = Object::Handle();
  entry = dict.At(index);
  // An empty spot will be found because we keep the hash set at most 75% full.
  while (!entry.IsNull()) {
    index = (index + 1) % dict_size;
    entry = dict.At(index);
  }

  // Insert the object at the empty slot.
  dict.SetAt(index, obj);
  Smi& used = Smi::Handle();
  used ^= dict.At(dict_size);
  intptr_t used_elements = used.Value() + 1;  // One more element added.
  used = Smi::New(used_elements);
  dict.SetAt(dict_size, used);  // Update used count.

  // Rehash if symbol_table is 75% full.
  if (used_elements > ((dict_size / 4) * 3)) {
    GrowDictionary(dict, dict_size);
  }

  // Invalidate the cache of loaded scripts.
  if (loaded_scripts() != Array::null()) {
    StorePointer(&raw_ptr()->loaded_scripts_, Array::null());
  }
}


void Library::AddClass(const Class& cls) const {
  AddObject(cls, String::Handle(cls.Name()));
  // Link class to this library.
  cls.set_library(*this);
}


RawArray* Library::LoadedScripts() const {
  // We compute the list of loaded scripts lazily. The result is
  // cached in loaded_scripts_.
  if (loaded_scripts() == Array::null()) {
    // Iterate over the library dictionary and collect all scripts.
    const GrowableObjectArray& scripts =
        GrowableObjectArray::Handle(GrowableObjectArray::New(8));
    Object& entry = Object::Handle();
    Function& func = Function::Handle();
    Field& field = Field::Handle();
    Class& cls = Class::Handle();
    Script& owner_script = Script::Handle();
    DictionaryIterator it(*this);
    Script& script_obj = Script::Handle();
    while (it.HasNext()) {
      entry = it.GetNext();
      if (entry.IsClass()) {
        cls ^= entry.raw();
      } else if (entry.IsFunction()) {
        func ^= entry.raw();
        cls = func.owner();
      } else if (entry.IsField()) {
        field ^= entry.raw();
        cls = field.owner();
      } else {
        continue;
      }
      owner_script = cls.script();
      if (owner_script.IsNull()) {
        continue;
      }
      bool is_unique = true;
      for (int i = 0; i < scripts.Length(); i++) {
        script_obj ^= scripts.At(i);
        if (script_obj.raw() == owner_script.raw()) {
          // We already have a reference to this script.
          is_unique = false;
          break;
        }
      }
      if (is_unique) {
        // Add script to the list of scripts.
        scripts.Add(owner_script);
      }
    }

    // Create the array of scripts and cache it in loaded_scripts_.
    StorePointer(&raw_ptr()->loaded_scripts_, Array::MakeArray(scripts));
  }
  return loaded_scripts();
}


// TODO(hausner): we might want to add a script dictionary to the
// library class to make this lookup faster.
RawScript* Library::LookupScript(const String& url) const {
  const Array& scripts = Array::Handle(LoadedScripts());
  Script& script = Script::Handle();
  String& script_url = String::Handle();
  intptr_t num_scripts = scripts.Length();
  for (int i = 0; i < num_scripts; i++) {
    script ^= scripts.At(i);
    script_url = script.url();
    if (script_url.Equals(url)) {
      return script.raw();
    }
  }
  return Script::null();
}


RawFunction* Library::LookupFunctionInSource(const String& script_url,
                                             intptr_t line_number) const {
  Script& script = Script::Handle(LookupScript(script_url));
  if (script.IsNull()) {
    // The given script url is not loaded into this library.
    return Function::null();
  }

  // Determine token position at given line number.
  intptr_t token_index_at_line = script.TokenIndexAtLine(line_number);
  if (token_index_at_line < 0) {
    // Script does not contain the given line number.
    return Function::null();
  }

  return LookupFunctionInScript(script, token_index_at_line);
}


RawFunction* Library::LookupFunctionInScript(const Script& script,
                                             intptr_t token_index) const {
  Class& cls = Class::Handle();
  Function& func = Function::Handle();
  ClassDictionaryIterator it(*this);
  while (it.HasNext()) {
    cls = it.GetNextClass();
    if (script.raw() == cls.script()) {
      func = cls.LookupFunctionAtToken(token_index);
      if (!func.IsNull()) {
        return func.raw();
      }
    }
  }
  // Look in anonymous classes for toplevel functions.
  Array& anon_classes = Array::Handle(this->raw_ptr()->anonymous_classes_);
  intptr_t num_anonymous = raw_ptr()->num_anonymous_;
  for (int i = 0; i < num_anonymous; i++) {
    cls ^= anon_classes.At(i);
    ASSERT(!cls.IsNull());
    if (script.raw() == cls.script()) {
      func = cls.LookupFunctionAtToken(token_index);
      if (!func.IsNull()) {
        return func.raw();
      }
    }
  }
  return Function::null();
}


RawObject* Library::LookupLocalObject(const String& name) const {
  Isolate* isolate = Isolate::Current();
  const Array& dict = Array::Handle(isolate, dictionary());
  intptr_t dict_size = dict.Length() - 1;
  intptr_t index = name.Hash() % dict_size;

  Object& entry = Object::Handle(isolate, Object::null());
  Class& cls = Class::Handle(isolate, Class::null());
  Function& func = Function::Handle(isolate, Function::null());
  Field& field = Field::Handle(isolate, Field::null());
  LibraryPrefix& library_prefix = LibraryPrefix::Handle(isolate,
                                                        LibraryPrefix::null());
  String& entry_name = String::Handle(isolate, String::null());
  entry = dict.At(index);
  // Search the entry in the hash set.
  while (!entry.IsNull()) {
    // TODO(hausner): find a better way to handle this polymorphism.
    // Either introduce a common base class for Class, Function, Field
    // and LibraryPrefix or make the name() function virtual in Object.
    if (entry.IsClass()) {
      cls ^= entry.raw();
      entry_name = cls.Name();
    } else if (entry.IsFunction()) {
      func ^= entry.raw();
      entry_name = func.name();
    } else if (entry.IsField()) {
      field ^= entry.raw();
      entry_name = field.name();
    } else if (entry.IsLibraryPrefix()) {
      library_prefix ^= entry.raw();
      entry_name = library_prefix.name();
    } else {
      UNREACHABLE();
    }
    if (entry_name.Equals(name)) {
      return entry.raw();
    }
    index = (index + 1) % dict_size;
    entry = dict.At(index);
  }
  return Class::null();
}


static bool ShouldBePrivate(const String& name) {
  return
      (name.Length() >= 1 &&
       name.CharAt(0) == '_') ||
      (name.Length() >= 5 &&
       (name.CharAt(4) == '_' &&
        (name.CharAt(0) == 'g' || name.CharAt(0) == 's') &&
        name.CharAt(1) == 'e' &&
        name.CharAt(2) == 't' &&
        name.CharAt(3) == ':'));
}


RawField* Library::LookupLocalField(const String& name) const {
  Isolate* isolate = Isolate::Current();
  Field& field = Field::Handle(isolate, Field::null());
  Object& obj = Object::Handle(isolate, Object::null());
  obj = LookupLocalObject(name);
  if (obj.IsNull() && ShouldBePrivate(name)) {
    String& private_name = String::Handle(isolate, PrivateName(name));
    obj = LookupLocalObject(private_name);
  }
  if (!obj.IsNull()) {
    if (obj.IsField()) {
      field ^= obj.raw();
      return field.raw();
    }
  }

  // No field found.
  return Field::null();
}


RawFunction* Library::LookupLocalFunction(const String& name) const {
  Isolate* isolate = Isolate::Current();
  Function& function = Function::Handle(isolate, Function::null());
  Object& obj = Object::Handle(isolate, Object::null());
  obj = LookupLocalObject(name);
  if (obj.IsNull() && ShouldBePrivate(name)) {
    String& private_name = String::Handle(isolate, PrivateName(name));
    obj = LookupLocalObject(private_name);
  }
  if (!obj.IsNull()) {
    if (obj.IsFunction()) {
      function ^= obj.raw();
      return function.raw();
    }
  }

  // No function found.
  return Function::null();
}


RawObject* Library::LookupObjectFiltered(const String& name,
                                         const Library& filter_lib) const {
  // First check if name is found in the local scope of the library.
  Object& obj = Object::Handle(LookupLocalObject(name));
  if (!obj.IsNull()) {
    return obj.raw();
  }
  // Now check if name is found in the top level scope of any imported libs.
  const Array& imports = Array::Handle(this->imports());
  Library& import_lib = Library::Handle();
  for (intptr_t j = 0; j < this->num_imports(); j++) {
    import_lib ^= imports.At(j);
    // Skip over the library that we need to filter out.
    if (!filter_lib.IsNull() && import_lib.raw() == filter_lib.raw()) {
      continue;
    }
    obj = import_lib.LookupLocalObject(name);
    if (!obj.IsNull()) {
      return obj.raw();
    }
  }
  return Object::null();
}


RawObject* Library::LookupObject(const String& name) const {
  return LookupObjectFiltered(name, Library::Handle());
}


RawLibrary* Library::LookupObjectInImporter(const String& name) const {
  Isolate* isolate = Isolate::Current();
  const Array& imported_into_libs = Array::Handle(isolate,
                                                  this->imported_into());
  Library& lib = Library::Handle(isolate, Library::null());
  Object& obj = Object::Handle(isolate, Object::null());
  for (intptr_t i = 0; i < this->num_imported_into(); i++) {
    lib ^= imported_into_libs.At(i);
    obj = lib.LookupObjectFiltered(name, *this);
    if (!obj.IsNull()) {
      // If the object found is a class, field or function extract the
      // library in which it is defined as it might be defined in one of
      // the imported libraries.
      Class& cls = Class::Handle(isolate, Class::null());
      Function& func = Function::Handle(isolate, Function::null());
      Field& field = Field::Handle(isolate, Field::null());
      if (obj.IsClass()) {
        cls ^= obj.raw();
        lib ^= cls.library();
      } else if (obj.IsFunction()) {
        func ^= obj.raw();
        cls ^= func.owner();
        lib ^= cls.library();
      } else if (obj.IsField()) {
        field ^= obj.raw();
        cls ^= field.owner();
        lib ^= cls.library();
      }
      return lib.raw();
    }
  }
  return Library::null();
}


RawString* Library::DuplicateDefineErrorString(const String& entry_name,
                                               const Library& conflict) const {
  String& errstr = String::Handle();
  Array& array = Array::Handle(Array::New(7));
  errstr = String::New("'");
  array.SetAt(0, errstr);
  array.SetAt(1, entry_name);
  errstr = String::New("' is defined in '");
  array.SetAt(2, errstr);
  errstr = url();
  array.SetAt(3, errstr);
  errstr = String::New("' and '");
  array.SetAt(4, errstr);
  errstr = conflict.url();
  array.SetAt(5, errstr);
  errstr = String::New("'");
  array.SetAt(6, errstr);
  errstr = String::ConcatAll(array);
  return errstr.raw();
}


RawString* Library::FindDuplicateDefinition() const {
  DictionaryIterator it(*this);
  Object& obj = Object::Handle();
  Class& cls = Class::Handle();
  Function& func = Function::Handle();
  Field& field = Field::Handle();
  String& entry_name = String::Handle();
  String& error_message = String::Handle();
  Library& conflicting_lib = Library::Handle();
  LibraryPrefix& lib_prefix = LibraryPrefix::Handle();
  while (it.HasNext()) {
    obj = it.GetNext();
    ASSERT(!obj.IsNull());
    if (obj.IsClass()) {
      cls ^= obj.raw();
      if (cls.IsCanonicalSignatureClass()) {
        continue;
      }
      entry_name = cls.Name();
    } else if (obj.IsFunction()) {
      func ^= obj.raw();
      entry_name = func.name();
    } else if (obj.IsField()) {
      field ^= obj.raw();
      entry_name = field.name();
    } else if (obj.IsLibraryPrefix()) {
      // For library prefix objects we check to make sure there are no
      // duplicate definitions within the libraries imported using this
      // prefix.
      lib_prefix ^= obj.raw();
      error_message = lib_prefix.CheckForDuplicateDefinition();
      if (!error_message.IsNull()) {
        return error_message.raw();
      }
      // We don't check library prefixes defined in this library for
      // conflicts because they are not visible in the importing scope and
      // hence cannot cause any duplicate definitions.
      continue;
    } else {
      UNREACHABLE();
    }
    conflicting_lib = LookupObjectInImporter(entry_name);
    if (!conflicting_lib.IsNull()) {
      return this->DuplicateDefineErrorString(entry_name, conflicting_lib);
    }
  }
  return String::null();
}


RawClass* Library::LookupClass(const String& name) const {
  Object& obj = Object::Handle(LookupObject(name));
  if (!obj.IsNull() && obj.IsClass()) {
    return Class::CheckedHandle(obj.raw()).raw();
  }
  return Class::null();
}


RawClass* Library::LookupLocalClass(const String& name) const {
  Object& obj = Object::Handle(LookupLocalObject(name));
  if (!obj.IsNull() && obj.IsClass()) {
    return Class::CheckedHandle(obj.raw()).raw();
  }
  return Class::null();
}


RawLibraryPrefix* Library::LookupLocalLibraryPrefix(const String& name) const {
  Object& obj = Object::Handle(LookupLocalObject(name));
  if (!obj.IsNull() && obj.IsLibraryPrefix()) {
    return LibraryPrefix::CheckedHandle(obj.raw()).raw();
  }
  return LibraryPrefix::null();
}


void Library::AddAnonymousClass(const Class& cls) const {
  intptr_t num_anonymous = this->raw_ptr()->num_anonymous_;
  Array& anon_array = Array::Handle(this->raw_ptr()->anonymous_classes_);
  if (num_anonymous == anon_array.Length()) {
    intptr_t new_len = (num_anonymous == 0) ? 4 : num_anonymous * 2;
    anon_array = Array::Grow(anon_array, new_len);
    StorePointer(&raw_ptr()->anonymous_classes_, anon_array.raw());
  }
  anon_array.SetAt(num_anonymous, cls);
  num_anonymous++;
  raw_ptr()->num_anonymous_ = num_anonymous;
}


RawLibrary* Library::LookupImport(const String& url) const {
  Isolate* isolate = Isolate::Current();
  const Array& imports = Array::Handle(isolate, this->imports());
  intptr_t num_imports = this->num_imports();
  Library& lib = Library::Handle(isolate, Library::null());
  String& import_url = String::Handle(isolate, String::null());
  for (int i = 0; i < num_imports; i++) {
    lib ^= imports.At(i);
    import_url = lib.url();
    if (url.Equals(import_url)) {
      return lib.raw();
    }
  }
  return Library::null();
}


RawString* Library::LookupImportMap(const String& ident) const {
  Array& import_map = Array::Handle(this->import_map());
  intptr_t length = import_map.Length();
  intptr_t index = 0;
  String& name = String::Handle();
  while (index < (length - 1)) {
    name ^= import_map.At(index);
    if (name.Equals(ident)) {
      name ^= import_map.At(index + 1);
      return name.raw();
    }
    index += 2;
  }
  return String::null();
}


void Library::AddImport(const Library& library) const {
  Array& imports = Array::Handle(this->imports());
  intptr_t capacity = imports.Length();
  if (num_imports() == capacity) {
    capacity = capacity + kImportsCapacityIncrement;
    imports = Array::Grow(imports, capacity);
    StorePointer(&raw_ptr()->imports_, imports.raw());
  }
  intptr_t index = num_imports();
  imports.SetAt(index, library);
  set_num_imports(index + 1);
  library.AddImportedInto(*this);
}


void Library::AddImportedInto(const Library& library) const {
  Array& imported_into = Array::Handle(this->imported_into());
  intptr_t capacity = imported_into.Length();
  if (num_imported_into() == capacity) {
    capacity = capacity + kImportedIntoCapacityIncrement;
    imported_into = Array::Grow(imported_into, capacity);
    StorePointer(&raw_ptr()->imported_into_, imported_into.raw());
  }
  intptr_t index = num_imported_into();
  imported_into.SetAt(index, library);
  set_num_imported_into(index + 1);
}


void Library::InitClassDictionary() const {
  // The last element of the dictionary specifies the number of in use slots.
  // TODO(iposva): Find reasonable initial size.
  const int kInitialElementCount = 16;

  const Array& dictionary =
      Array::Handle(Array::New(kInitialElementCount + 1, Heap::kOld));
  dictionary.SetAt(kInitialElementCount, Smi::Handle(Smi::New(0)));
  StorePointer(&raw_ptr()->dictionary_, dictionary.raw());
}


void Library::InitImportList() const {
  const Array& imports =
      Array::Handle(Array::New(kInitialImportsCapacity, Heap::kOld));
  StorePointer(&raw_ptr()->imports_, imports.raw());
  raw_ptr()->num_imports_ = 0;
}


void Library::InitImportedIntoList() const {
  const Array& imported_into =
      Array::Handle(Array::New(kInitialImportedIntoCapacity, Heap::kOld));
  StorePointer(&raw_ptr()->imported_into_, imported_into.raw());
  raw_ptr()->num_imported_into_ = 0;
}


RawLibrary* Library::New() {
  const Class& library_class = Class::Handle(Object::library_class());
  RawObject* raw = Object::Allocate(library_class,
                                    Library::InstanceSize(),
                                    Heap::kOld);
  return reinterpret_cast<RawLibrary*>(raw);
}


RawLibrary* Library::NewLibraryHelper(const String& url,
                                      bool import_core_lib) {
  const Library& result = Library::Handle(Library::New());
  result.raw_ptr()->name_ = url.raw();
  result.raw_ptr()->url_ = url.raw();
  result.raw_ptr()->private_key_ = Scanner::AllocatePrivateKey(result);
  result.raw_ptr()->dictionary_ = Array::Empty();
  result.raw_ptr()->anonymous_classes_ = Array::Empty();
  result.raw_ptr()->num_anonymous_ = 0;
  result.raw_ptr()->import_map_ = Array::Empty();
  result.raw_ptr()->imports_ = Array::Empty();
  result.raw_ptr()->next_registered_ = Library::null();
  result.raw_ptr()->loaded_scripts_ = Array::null();
  result.set_native_entry_resolver(NULL);
  result.raw_ptr()->corelib_imported_ = true;
  result.raw_ptr()->load_state_ = RawLibrary::kAllocated;
  result.InitClassDictionary();
  result.InitImportList();
  result.InitImportedIntoList();
  if (import_core_lib) {
    Library& core_lib = Library::Handle(Library::CoreLibrary());
    ASSERT(!core_lib.IsNull());
    result.AddImport(core_lib);
  }
  return result.raw();
}


RawLibrary* Library::New(const String& url) {
  return NewLibraryHelper(url, true);
}


void Library::InitCoreLibrary(Isolate* isolate) {
  const String& core_lib_url = String::Handle(String::NewSymbol("dart:core"));
  const Library& core_lib =
      Library::Handle(Library::NewLibraryHelper(core_lib_url, false));
  core_lib.Register();
  isolate->object_store()->set_core_library(core_lib);
  const String& core_impl_lib_url =
      String::Handle(String::NewSymbol("dart:coreimpl"));
  const Library& core_impl_lib =
      Library::Handle(Library::NewLibraryHelper(core_impl_lib_url, false));
  isolate->object_store()->set_core_impl_library(core_impl_lib);
  core_impl_lib.Register();
  core_lib.AddImport(core_impl_lib);
  core_impl_lib.AddImport(core_lib);
  isolate->object_store()->set_root_library(Library::Handle());
}


void Library::InitIsolateLibrary(Isolate* isolate) {
  const String& url = String::Handle(String::NewSymbol("dart:isolate"));
  const Library& lib = Library::Handle(Library::New(url));
  lib.Register();
  isolate->object_store()->set_isolate_library(lib);
}


void Library::InitMirrorsLibrary(Isolate* isolate) {
  const String& url = String::Handle(String::NewSymbol("dart:mirrors"));
  const Library& lib = Library::Handle(Library::New(url));
  lib.Register();
  const Library& isolate_lib = Library::Handle(Library::IsolateLibrary());
  lib.AddImport(isolate_lib);
  isolate->object_store()->set_mirrors_library(lib);
}


void Library::InitNativeWrappersLibrary(Isolate* isolate) {
  static const int kNumNativeWrappersClasses = 4;
  ASSERT(kNumNativeWrappersClasses > 0 && kNumNativeWrappersClasses < 10);
  const String& native_flds_lib_url = String::Handle(
      String::NewSymbol("dart:nativewrappers"));
  Library& native_flds_lib = Library::Handle(
      Library::NewLibraryHelper(native_flds_lib_url, false));
  native_flds_lib.Register();
  isolate->object_store()->set_native_wrappers_library(native_flds_lib);
  static const char* const kNativeWrappersClass = "NativeFieldWrapperClass";
  static const int kNameLength = 25;
  ASSERT(kNameLength == (strlen(kNativeWrappersClass) + 1 + 1));
  char name_buffer[kNameLength];
  String& cls_name = String::Handle();
  for (int fld_cnt = 1; fld_cnt <= kNumNativeWrappersClasses; fld_cnt++) {
    OS::SNPrint(name_buffer,
                kNameLength,
                "%s%d",
                kNativeWrappersClass,
                fld_cnt);
    cls_name = String::NewSymbol(name_buffer);
    Class::NewNativeWrapper(&native_flds_lib, cls_name, fld_cnt);
  }
}


RawLibrary* Library::LookupLibrary(const String &url) {
  Isolate* isolate = Isolate::Current();
  Library& lib = Library::Handle(isolate, Library::null());
  String& lib_url = String::Handle(isolate, String::null());
  lib = isolate->object_store()->registered_libraries();
  while (!lib.IsNull()) {
    lib_url = lib.url();
    if (lib_url.Equals(url)) {
      return lib.raw();
    }
    lib = lib.next_registered();
  }
  return Library::null();
}


RawString* Library::CheckForDuplicateDefinition() {
  Library& lib = Library::Handle();
  Isolate* isolate = Isolate::Current();
  ASSERT(isolate != NULL);
  ObjectStore* object_store = isolate->object_store();
  ASSERT(object_store != NULL);
  lib ^= object_store->registered_libraries();
  String& error_message = String::Handle();
  while (!lib.IsNull()) {
    error_message = lib.FindDuplicateDefinition();
    if (!error_message.IsNull()) {
      return error_message.raw();
    }
    lib ^= lib.next_registered();
  }
  return String::null();
}


bool Library::IsKeyUsed(intptr_t key) {
  intptr_t lib_key;
  Library& lib = Library::Handle();
  lib = Isolate::Current()->object_store()->registered_libraries();
  String& lib_url = String::Handle();
  while (!lib.IsNull()) {
    lib_url ^= lib.url();
    lib_key = lib_url.Hash();
    if (lib_key == key) {
      return true;
    }
    lib = lib.next_registered();
  }
  return false;
}


RawString* Library::PrivateName(const String& name) const {
  ASSERT(ShouldBePrivate(name));
  // ASSERT(strchr(name, '@') == NULL);
  String& str = String::Handle();
  str ^= name.raw();
  str = String::Concat(str, String::Handle(this->private_key()));
  str = String::NewSymbol(str);
  return str.raw();
}


void Library::Register() const {
  ASSERT(Library::LookupLibrary(String::Handle(url())) == Library::null());
  raw_ptr()->next_registered_ =
      Isolate::Current()->object_store()->registered_libraries();
  Isolate::Current()->object_store()->set_registered_libraries(*this);
}


RawLibrary* Library::CoreLibrary() {
  return Isolate::Current()->object_store()->core_library();
}


RawLibrary* Library::CoreImplLibrary() {
  return Isolate::Current()->object_store()->core_impl_library();
}


RawLibrary* Library::IsolateLibrary() {
  return Isolate::Current()->object_store()->isolate_library();
}


RawLibrary* Library::MirrorsLibrary() {
  return Isolate::Current()->object_store()->mirrors_library();
}


RawLibrary* Library::NativeWrappersLibrary() {
  return Isolate::Current()->object_store()->native_wrappers_library();
}


const char* Library::ToCString() const {
  const char* kFormat = "Library:'%s'";
  const String& name = String::Handle(url());
  intptr_t len = OS::SNPrint(NULL, 0, kFormat, name.ToCString()) + 1;
  char* chars = reinterpret_cast<char*>(
      Isolate::Current()->current_zone()->Allocate(len));
  OS::SNPrint(chars, len, kFormat, name.ToCString());
  return chars;
}


RawLibrary* LibraryPrefix::GetLibrary(int index) const {
  Library& lib = Library::Handle();
  if ((index >= 0) || (index < num_libs())) {
    Array& libs = Array::Handle(libraries());
    lib ^= libs.At(index);
  }
  return lib.raw();
}


void LibraryPrefix::AddLibrary(const Library& library) const {
  Library& lib = Library::Handle();
  intptr_t num_current_libs = num_libs();

  // First check if the library is already in the list of libraries imported.
  if (num_current_libs > 0) {
    const String& url = String::Handle(library.url());
    String& lib_url = String::Handle();
    for (intptr_t i = 0; i < num_current_libs; i++) {
      lib = GetLibrary(i);
      ASSERT(!lib.IsNull());
      lib_url = lib.url();
      if (url.Equals(lib_url)) {
        return;  // Library already imported with same prefix.
      }
    }
  }

  // The library needs to be added to the list.
  Array& libs = Array::Handle(libraries());
  const intptr_t length = (libs.IsNull()) ? 0 : libs.Length();
  // Grow the list if it is full.
  if (num_current_libs >= length) {
    const intptr_t new_length = length + kIncrementSize;
    libs = Array::Grow(libs, new_length, Heap::kOld);
    set_libraries(libs);
  }
  libs.SetAt(num_current_libs, library);
  set_num_libs(num_current_libs + 1);
}


RawClass* LibraryPrefix::LookupLocalClass(const String& class_name) const {
  Array& libs = Array::Handle(libraries());
  Class& resolved_class = Class::Handle();
  Library& lib = Library::Handle();
  for (intptr_t i = 0; i < num_libs(); i++) {
    lib ^= libs.At(i);
    ASSERT(!lib.IsNull());
    resolved_class = lib.LookupLocalClass(class_name);
    if (!resolved_class.IsNull()) {
      return resolved_class.raw();
    }
  }
  return Class::null();
}


RawLibraryPrefix* LibraryPrefix::New() {
  const Class& library_prefix_class =
      Class::Handle(Object::library_prefix_class());
  RawObject* raw = Object::Allocate(library_prefix_class,
                                    LibraryPrefix::InstanceSize(),
                                    Heap::kOld);
  return reinterpret_cast<RawLibraryPrefix*>(raw);
}


RawLibraryPrefix* LibraryPrefix::New(const String& name, const Library& lib) {
  const LibraryPrefix& result = LibraryPrefix::Handle(LibraryPrefix::New());
  result.set_name(name);
  result.set_num_libs(0);
  result.AddLibrary(lib);
  return result.raw();
}


const char* LibraryPrefix::ToCString() const {
  const char* kFormat = "LibraryPrefix:'%s'";
  const String& prefix = String::Handle(name());
  intptr_t len = OS::SNPrint(NULL, 0, kFormat, prefix.ToCString()) + 1;
  char* chars = reinterpret_cast<char*>(
      Isolate::Current()->current_zone()->Allocate(len));
  OS::SNPrint(chars, len, kFormat, prefix.ToCString());
  return chars;
}


RawString* LibraryPrefix::CheckForDuplicateDefinition() const {
  Library& lib = Library::Handle();
  Library& conflicting_lib = Library::Handle();
  Object& obj = Object::Handle();
  Class& cls = Class::Handle();
  Function& func = Function::Handle();
  Field& field = Field::Handle();
  String& entry_name = String::Handle();

  for (intptr_t i = 0; i < num_libs(); i++) {
    lib = GetLibrary(i);
    ASSERT(!lib.IsNull());
    DictionaryIterator it(lib);
    while (it.HasNext()) {
      obj = it.GetNext();
      ASSERT(!obj.IsNull());
      if (obj.IsClass()) {
        cls ^= obj.raw();
        if (cls.IsCanonicalSignatureClass()) {
          continue;
        }
        entry_name = cls.Name();
      } else if (obj.IsFunction()) {
        func ^= obj.raw();
        entry_name = func.name();
      } else if (obj.IsField()) {
        field ^= obj.raw();
        entry_name = field.name();
      } else {
        // We don't check library prefixes defined in this library for
        // conflicts because they are not visible in the importing scope and
        // hence cannot cause any duplicate definitions.
        continue;
      }
      for (intptr_t j = i + 1; j < num_libs(); j++) {
        conflicting_lib = GetLibrary(j);
        ASSERT(!conflicting_lib.IsNull());
        // Check if name is found in the local scope of the library.
        obj = conflicting_lib.LookupLocalObject(entry_name);
        if (!obj.IsNull()) {
          return lib.DuplicateDefineErrorString(entry_name, conflicting_lib);
        }
      }
    }
  }
  return String::null();
}


void LibraryPrefix::set_name(const String& value) const {
  ASSERT(value.IsSymbol());
  StorePointer(&raw_ptr()->name_, value.raw());
}


void LibraryPrefix::set_libraries(const Array& value) const {
  StorePointer(&raw_ptr()->libraries_, value.raw());
}


void LibraryPrefix::set_num_libs(intptr_t value) const {
  raw_ptr()->num_libs_ = value;
}


RawError* Library::CompileAll() {
  Error& error = Error::Handle();
  Library& lib = Library::Handle(
      Isolate::Current()->object_store()->registered_libraries());
  Class& cls = Class::Handle();
  while (!lib.IsNull()) {
    ClassDictionaryIterator it(lib);
    while (it.HasNext()) {
      cls ^= it.GetNextClass();
      if (!cls.is_interface()) {
        error = Compiler::CompileAllFunctions(cls);
        if (!error.IsNull()) {
          return error.raw();
        }
      }
    }
    Array& anon_classes = Array::Handle(lib.raw_ptr()->anonymous_classes_);
    for (int i = 0; i < lib.raw_ptr()->num_anonymous_; i++) {
      cls ^= anon_classes.At(i);
      ASSERT(!cls.is_interface());
      error = Compiler::CompileAllFunctions(cls);
      if (!error.IsNull()) {
        return error.raw();
      }
    }
    lib = lib.next_registered();
  }
  return error.raw();
}


RawInstructions* Instructions::New(intptr_t size) {
  const Class& instructions_class = Class::Handle(Object::instructions_class());
  Instructions& result = Instructions::Handle();
  {
    uword aligned_size = Instructions::InstanceSize(size);
    RawObject* raw = Object::Allocate(instructions_class,
                                      aligned_size,
                                      Heap::kExecutable);
    NoGCScope no_gc;
    result ^= raw;
    result.set_size(size);
  }
  return result.raw();
}


const char* Instructions::ToCString() const {
  return "Instructions";
}


intptr_t PcDescriptors::Length() const {
  return Smi::Value(raw_ptr()->length_);
}


void PcDescriptors::SetLength(intptr_t value) const {
  // This is only safe because we create a new Smi, which does not cause
  // heap allocation.
  raw_ptr()->length_ = Smi::New(value);
}


uword PcDescriptors::PC(intptr_t index) const {
  return static_cast<uword>(*(EntryAddr(index, kPcEntry)));
}


void PcDescriptors::SetPC(intptr_t index, uword value) const {
  *(EntryAddr(index, kPcEntry)) = static_cast<intptr_t>(value);
}


PcDescriptors::Kind PcDescriptors::DescriptorKind(intptr_t index) const {
  return static_cast<PcDescriptors::Kind>(*(EntryAddr(index, kKindEntry)));
}


void PcDescriptors::SetKind(intptr_t index, PcDescriptors::Kind value) const {
  *(EntryAddr(index, kKindEntry)) = value;
}


intptr_t PcDescriptors::NodeId(intptr_t index) const {
  return Smi::Value(*SmiAddr(index, kNodeIdEntry));
}


void PcDescriptors::SetNodeId(intptr_t index, intptr_t value) const {
  *SmiAddr(index, kNodeIdEntry) = Smi::New(value);
}


intptr_t PcDescriptors::TokenIndex(intptr_t index) const {
  return Smi::Value(*SmiAddr(index, kTokenIndexEntry));
}


void PcDescriptors::SetTokenIndex(intptr_t index, intptr_t value) const {
  *SmiAddr(index, kTokenIndexEntry) = Smi::New(value);
}


intptr_t PcDescriptors::TryIndex(intptr_t index) const {
  return *(EntryAddr(index, kTryIndexEntry));
}


void PcDescriptors::SetTryIndex(intptr_t index, intptr_t value) const {
  *(EntryAddr(index, kTryIndexEntry)) = value;
}


RawPcDescriptors* PcDescriptors::New(intptr_t num_descriptors) {
  const Class& cls = Class::Handle(Object::pc_descriptors_class());
  PcDescriptors& result = PcDescriptors::Handle();
  {
    uword size = PcDescriptors::InstanceSize(num_descriptors);
    RawObject* raw = Object::Allocate(cls, size, Heap::kOld);
    NoGCScope no_gc;
    result ^= raw;
    result.SetLength(num_descriptors);
  }
  return result.raw();
}


const char* PcDescriptors::KindAsStr(intptr_t index) const {
  switch (DescriptorKind(index)) {
    case PcDescriptors::kDeopt: return "deopt";
    case PcDescriptors::kPatchCode: return "patch";
    case PcDescriptors::kIcCall: return "ic-call";
    case PcDescriptors::kFuncCall: return "fn-call";
    case PcDescriptors::kReturn: return "return";
    case PcDescriptors::kTypeTest: return "ty-test";
    case PcDescriptors::kOther: return "other";
  }
  UNREACHABLE();
  return "";
}


const char* PcDescriptors::ToCString() const {
  if (Length() == 0) {
    return "No pc descriptors\n";
  }
  const char* kFormat = "0x%x\t%s\t%ld\t%ld\t%ld\n";
  // First compute the buffer size required.
  intptr_t len = 0;
  for (intptr_t i = 0; i < Length(); i++) {
    len += OS::SNPrint(NULL, 0, kFormat,
        PC(i), KindAsStr(i), NodeId(i), TryIndex(i), TokenIndex(i));
  }
  // Allocate the buffer.
  char* buffer = reinterpret_cast<char*>(
      Isolate::Current()->current_zone()->Allocate(len + 1));
  // Layout the fields in the buffer.
  intptr_t index = 0;
  for (intptr_t i = 0; i < Length(); i++) {
    index += OS::SNPrint((buffer + index), (len - index), kFormat,
        PC(i), KindAsStr(i), NodeId(i), TryIndex(i), TokenIndex(i));
  }
  return buffer;
}


// Verify assumptions (in debug mode only).
// - No two deopt descriptors have the same node id (deoptimization).
// - No two ic-call descriptors have the same node id (type feedback).
// - No two descriptors of same kind have the same PC.
// A function without unique ids is marked as non-optimizable (e.g., because of
// finally blocks).
void PcDescriptors::Verify(bool check_ids) const {
#if defined(DEBUG)
  // TODO(srdjan): Implement a more efficient way to check, currently drop
  // the check for too large number of descriptors.
  if (Length() > 3000) {
    if (FLAG_trace_compiler) {
      OS::Print("Not checking pc decriptors, length %d\n", Length());
    }
    return;
  }
  for (intptr_t i = 0; i < Length(); i++) {
    uword pc = PC(i);
    PcDescriptors::Kind kind = DescriptorKind(i);
    // 'node_id' is set for kDeopt and kIcCall and must be unique for one kind.
    intptr_t node_id = AstNode::kNoId;
    if (check_ids) {
      if ((DescriptorKind(i) == PcDescriptors::kDeopt) ||
          (DescriptorKind(i) == PcDescriptors::kIcCall)) {
        node_id = NodeId(i);
      }
    }
    for (intptr_t k = i + 1; k < Length(); k++) {
      if (kind == DescriptorKind(k)) {
        if (node_id != AstNode::kNoId) {
          ASSERT(NodeId(k) != node_id);
        }
        ASSERT(pc != PC(k));
      }
    }
  }
#endif  // DEBUG
}


void Stackmap::SetCode(const Code& code) const {
  StorePointer(&raw_ptr()->code_, code.raw());
}


bool Stackmap::GetBit(intptr_t bit_offset) const {
  ASSERT(InRange(bit_offset));
  int byte_offset = bit_offset >> kBitsPerByteLog2;
  int bit_remainder = bit_offset & (kBitsPerByte - 1);
  uint8_t byte_mask = 1U << bit_remainder;
  uint8_t byte = raw_ptr()->data_[byte_offset];
  return (byte & byte_mask);
}


void Stackmap::SetBit(intptr_t bit_offset, bool value) const {
  ASSERT(InRange(bit_offset));
  int byte_offset = bit_offset >> kBitsPerByteLog2;
  int bit_remainder = bit_offset & (kBitsPerByte - 1);
  uint8_t byte_mask = 1U << bit_remainder;
  uint8_t* byte_addr = &(raw_ptr()->data_[byte_offset]);
  if (value) {
    *byte_addr |= byte_mask;
  } else {
    *byte_addr &= ~byte_mask;
  }
}


RawStackmap* Stackmap::New(uword pc_offset, BitmapBuilder* bmap) {
  const Class& cls = Class::Handle(Object::stackmap_class());
  ASSERT(!cls.IsNull());
  ASSERT(bmap != NULL);
  Stackmap& result = Stackmap::Handle();
  intptr_t size = bmap->SizeInBytes();
  {
    // Stackmap data objects are associated with a code object, allocate them
    // in old generation.
    RawObject* raw =
        Object::Allocate(cls, Stackmap::InstanceSize(size), Heap::kOld);
    NoGCScope no_gc;
    result ^= raw;
    result.set_bitmap_size_in_bytes(size);
  }
  result.SetPC(pc_offset);
  intptr_t bound = bmap->SizeInBits();
  for (intptr_t i = 0; i < bound; i++) {
    result.SetBit(i, bmap->Get(i));
  }
  result.SetMinBitOffset(bmap->Minimum());
  result.SetMaxBitOffset(bmap->Maximum());
  return result.raw();
}


void Stackmap::set_bitmap_size_in_bytes(intptr_t value) const {
  // This is only safe because we create a new Smi, which does not cause
  // heap allocation.
  raw_ptr()->bitmap_size_in_bytes_ = Smi::New(value);
}


const char* Stackmap::ToCString() const {
  if (IsNull()) {
    return "{null}";
  } else {
    intptr_t index = OS::SNPrint(NULL, 0, "0x%lx { ", PC());
    intptr_t alloc_size =
        index + ((MaximumBitOffset() + 1) * 2) + 2;  // "{ 1 0 .... }".
    Isolate* isolate = Isolate::Current();
    char* chars = reinterpret_cast<char*>(
        isolate->current_zone()->Allocate(alloc_size));
    index = OS::SNPrint(chars, alloc_size, "0x%lx { ", PC());
    for (intptr_t i = 0; i <= MaximumBitOffset(); i++) {
      index += OS::SNPrint((chars + index),
                           (alloc_size - index),
                           "%d ",
                           IsObject(i) ? 1 : 0);
    }
    OS::SNPrint((chars + index), (alloc_size - index), "}");
    return chars;
  }
}


RawString* LocalVarDescriptors::GetName(intptr_t var_index) const {
  ASSERT(var_index < Length());
  const Array& names = Array::Handle(raw_ptr()->names_);
  ASSERT(Length() == names.Length());
  const String& name = String::CheckedHandle(names.At(var_index));
  return name.raw();
}


void LocalVarDescriptors::GetScopeInfo(
                              intptr_t var_index,
                              intptr_t* scope_id,
                              intptr_t* begin_token_pos,
                              intptr_t* end_token_pos) const {
  ASSERT(var_index < Length());
  RawLocalVarDescriptors::VarInfo *info = &raw_ptr()->data_[var_index];
  *scope_id = info->scope_id;
  *begin_token_pos = info->begin_pos;
  *end_token_pos = info->end_pos;
}


intptr_t LocalVarDescriptors::GetSlotIndex(intptr_t var_index) const {
  ASSERT(var_index < Length());
  RawLocalVarDescriptors::VarInfo *info = &raw_ptr()->data_[var_index];
  return info->index;
}


void LocalVarDescriptors::SetVar(intptr_t var_index,
                                 const String& name,
                                 intptr_t stack_slot,
                                 intptr_t scope_id,
                                 intptr_t begin_pos,
                                 intptr_t end_pos) const {
  ASSERT(var_index < Length());
  const Array& names = Array::Handle(raw_ptr()->names_);
  ASSERT(Length() == names.Length());
  names.SetAt(var_index, name);
  RawLocalVarDescriptors::VarInfo *info = &raw_ptr()->data_[var_index];
  info->index = stack_slot;
  info->scope_id = scope_id;
  info->begin_pos = begin_pos;
  info->end_pos = end_pos;
}


const char* LocalVarDescriptors::ToCString() const {
  UNIMPLEMENTED();
  return "LocalVarDescriptors";
}


RawLocalVarDescriptors* LocalVarDescriptors::New(intptr_t num_variables) {
  const Class& cls = Class::Handle(Object::var_descriptors_class());
  LocalVarDescriptors& result = LocalVarDescriptors::Handle();
  {
    uword size = LocalVarDescriptors::InstanceSize(num_variables);
    RawObject* raw = Object::Allocate(cls, size, Heap::kOld);
    NoGCScope no_gc;
    result ^= raw;
    result.raw_ptr()->length_ = num_variables;
  }
  const Array& names = Array::Handle(Array::New(num_variables, Heap::kOld));
  result.raw_ptr()->names_ = names.raw();
  return result.raw();
}


intptr_t LocalVarDescriptors::Length() const {
  return raw_ptr()->length_;
}


intptr_t ExceptionHandlers::Length() const {
  return Smi::Value(raw_ptr()->length_);
}


void ExceptionHandlers::SetLength(intptr_t value) const {
  // This is only safe because we create a new Smi, which does not cause
  // heap allocation.
  raw_ptr()->length_ = Smi::New(value);
}


intptr_t ExceptionHandlers::TryIndex(intptr_t index) const {
  return *(EntryAddr(index, kTryIndexEntry));
}


void ExceptionHandlers::SetTryIndex(intptr_t index, intptr_t value) const {
  *(EntryAddr(index, kTryIndexEntry)) = value;
}


intptr_t ExceptionHandlers::HandlerPC(intptr_t index) const {
  return *(EntryAddr(index, kHandlerPcEntry));
}


void ExceptionHandlers::SetHandlerPC(intptr_t index,
                                     intptr_t value) const {
  *(EntryAddr(index, kHandlerPcEntry)) = value;
}


RawExceptionHandlers* ExceptionHandlers::New(intptr_t num_handlers) {
  const Class& cls = Class::Handle(Object::exception_handlers_class());
  ExceptionHandlers& result = ExceptionHandlers::Handle();
  {
    uword size = ExceptionHandlers::InstanceSize(num_handlers);
    RawObject* raw = Object::Allocate(cls, size, Heap::kOld);
    NoGCScope no_gc;
    result ^= raw;
    result.SetLength(num_handlers);
  }
  return result.raw();
}


const char* ExceptionHandlers::ToCString() const {
  if (Length() == 0) {
    return "No exception handlers\n";
  }
  // First compute the buffer size required.
  intptr_t len = 0;
  for (intptr_t i = 0; i < Length(); i++) {
    len += OS::SNPrint(NULL, 0, "%ld => 0x%x\n",
                       TryIndex(i), HandlerPC(i));
  }
  // Allocate the buffer.
  char* buffer = reinterpret_cast<char*>(
      Isolate::Current()->current_zone()->Allocate(len + 1));
  // Layout the fields in the buffer.
  intptr_t index = 0;
  for (intptr_t i = 0; i < Length(); i++) {
    index += OS::SNPrint((buffer + index),
                         (len - index),
                         "%ld => 0x%x\n",
                         TryIndex(i),
                         HandlerPC(i));
  }
  return buffer;
}


void Code::set_stackmaps(const Array& maps) const {
  StorePointer(&raw_ptr()->stackmaps_, maps.raw());
}


RawCode* Code::New(int pointer_offsets_length) {
  const Class& cls = Class::Handle(Object::code_class());
  Code& result = Code::Handle();
  {
    uword size = Code::InstanceSize(pointer_offsets_length);
    RawObject* raw = Object::Allocate(cls, size, Heap::kOld);
    NoGCScope no_gc;
    result ^= raw;
    result.set_pointer_offsets_length(pointer_offsets_length);
    result.set_is_optimized(false);
  }
  return result.raw();
}


RawCode* Code::FinalizeCode(const char* name, Assembler* assembler) {
  ASSERT(assembler != NULL);

  // Allocate the Instructions object.
  Instructions& instrs =
      Instructions::ZoneHandle(Instructions::New(assembler->CodeSize()));

  // Copy the instructions into the instruction area and apply all fixups.
  // Embedded pointers are still in handles at this point.
  MemoryRegion region(reinterpret_cast<void*>(instrs.EntryPoint()),
                      instrs.size());
  assembler->FinalizeInstructions(region);
  DebugInfo* pprof_symbol_generator = Dart::pprof_symbol_generator();
  if (pprof_symbol_generator != NULL) {
    pprof_symbol_generator->AddCode(instrs.EntryPoint(), instrs.size());
    pprof_symbol_generator->AddCodeRegion(name,
                                          instrs.EntryPoint(),
                                          instrs.size());
  }
  if (FLAG_generate_gdb_symbols) {
    intptr_t prolog_offset = assembler->prolog_offset();
    if (prolog_offset > 0) {
      // In order to ensure that gdb sees the first instruction of a function
      // as the prolog sequence we register two symbols for the cases when
      // the prolog sequence is not the first instruction:
      // <name>_entry is used for code preceding the prolog sequence.
      // <name> for rest of the code (first instruction is prolog sequence).
      const char* kFormat = "%s_%s";
      intptr_t len = OS::SNPrint(NULL, 0, kFormat, name, "entry");
      char* pname = reinterpret_cast<char*>(
          Isolate::Current()->current_zone()->Allocate(len + 1));
      OS::SNPrint(pname, (len + 1), kFormat, name, "entry");
      DebugInfo::RegisterSection(pname, instrs.EntryPoint(), prolog_offset);
      DebugInfo::RegisterSection(name,
                                 (instrs.EntryPoint() + prolog_offset),
                                 (instrs.size() - prolog_offset));
    } else {
      DebugInfo::RegisterSection(name, instrs.EntryPoint(), instrs.size());
    }
  }

  const ZoneGrowableArray<int>& pointer_offsets =
      assembler->GetPointerOffsets();

  // Allocate the code object.
  Code& code = Code::ZoneHandle(Code::New(pointer_offsets.length()));
  {
    NoGCScope no_gc;

    // Set pointer offsets list in Code object and resolve all handles in
    // the instruction stream to raw objects.
    ASSERT(code.pointer_offsets_length() == pointer_offsets.length());
    for (int i = 0; i < pointer_offsets.length(); i++) {
      int offset_in_instrs = pointer_offsets[i];
      code.SetPointerOffsetAt(i, offset_in_instrs);
      const Object* object = region.Load<const Object*>(offset_in_instrs);
      region.Store<RawObject*>(offset_in_instrs, object->raw());
    }

    // Hook up Code and Instruction objects.
    instrs.set_code(code.raw());
    code.set_instructions(instrs.raw());
  }
  return code.raw();
}


intptr_t Code::GetTokenIndexOfPC(uword pc) const {
  intptr_t token_index = -1;
  const PcDescriptors& descriptors = PcDescriptors::Handle(pc_descriptors());
  for (intptr_t i = 0; i < descriptors.Length(); i++) {
    if (descriptors.PC(i) == pc) {
      token_index = descriptors.TokenIndex(i);
      break;
    }
  }
  return token_index;
}


uword Code::GetDeoptPcAtNodeId(intptr_t node_id) const {
  const PcDescriptors& descriptors = PcDescriptors::Handle(pc_descriptors());
  for (intptr_t i = 0; i < descriptors.Length(); i++) {
    if ((descriptors.NodeId(i) == node_id) &&
        (descriptors.DescriptorKind(i) == PcDescriptors::kDeopt)) {
      return descriptors.PC(i);
    }
  }
  return 0;
}


uword Code::GetTypeTestAtNodeId(intptr_t node_id) const {
  const PcDescriptors& descriptors = PcDescriptors::Handle(pc_descriptors());
  for (intptr_t i = 0; i < descriptors.Length(); i++) {
    if ((descriptors.NodeId(i) == node_id) &&
        (descriptors.DescriptorKind(i) == PcDescriptors::kTypeTest)) {
      return descriptors.PC(i);
    }
  }
  return 0;
}


const char* Code::ToCString() const {
  const char* kFormat = "Code entry:0x%d";
  intptr_t len = OS::SNPrint(NULL, 0, kFormat, EntryPoint());
  char* chars = reinterpret_cast<char*>(
      Isolate::Current()->current_zone()->Allocate(len));
  OS::SNPrint(chars, len, kFormat, EntryPoint());
  return chars;
}


uword Code::GetPatchCodePc() const {
  const PcDescriptors& descriptors = PcDescriptors::Handle(pc_descriptors());
  for (intptr_t i = 0; i < descriptors.Length(); i++) {
    if (descriptors.DescriptorKind(i) == PcDescriptors::kPatchCode) {
      return descriptors.PC(i);
    }
  }
  return 0;
}


bool Code::ObjectExistInArea(intptr_t start_offset, intptr_t end_offset) const {
  for (intptr_t i = 0; i < this->pointer_offsets_length(); i++) {
    const intptr_t offset = this->GetPointerOffsetAt(i);
    if ((start_offset <= offset) && (offset < end_offset)) {
      return false;
    }
  }
  return true;
}


void Code::ExtractIcDataArraysAtCalls(
    GrowableArray<intptr_t>* node_ids,
    const GrowableObjectArray& ic_data_objs) const {
  ASSERT(node_ids != NULL);
  ASSERT(!ic_data_objs.IsNull());
  const PcDescriptors& descriptors =
      PcDescriptors::Handle(this->pc_descriptors());
  ICData& ic_data_obj = ICData::Handle();
  for (intptr_t i = 0; i < descriptors.Length(); i++) {
    if (descriptors.DescriptorKind(i) == PcDescriptors::kIcCall) {
      node_ids->Add(descriptors.NodeId(i));
      ic_data_obj = CodePatcher::GetInstanceCallIcDataAt(descriptors.PC(i));
      ic_data_objs.Add(ic_data_obj);
    }
  }
}


RawStackmap* Code::GetStackmap(uword pc, Array* maps, Stackmap* map) const {
  // This code is used only during iterating frames during a GC and hence
  // it should not in turn start a GC.
  NoGCScope no_gc;
  if (stackmaps() == Array::null()) {
    // No stack maps are present in the code object which means this
    // frame relies on tagged pointers.
    return Stackmap::null();
  }
  // A stack map is present in the code object, use the stack map to visit
  // frame slots which are marked as having objects.
  RawStackmap* previous_map = Stackmap::null();
  *maps = stackmaps();
  *map = Stackmap::null();
  for (intptr_t i = 0; i < maps->Length(); i++) {
    *map ^= maps->At(i);
    ASSERT(!map->IsNull());
    if (map->PC() == pc) {
      break;  // We found a stack map for this frame.
    }
    if (map->PC() > pc) {
      // We have not found a stackmap corresponding to the PC of this frame,
      // we will use the closest previous stack map.
      *map = previous_map;
      break;
    }
    previous_map = map->raw();
  }
  return map->raw();
}


RawContext* Context::New(intptr_t num_variables, Heap::Space space) {
  ASSERT(num_variables >= 0);

  const Class& context_class = Class::Handle(Object::context_class());
  Context& result = Context::Handle();
  {
    RawObject* raw = Object::Allocate(context_class,
                                      Context::InstanceSize(num_variables),
                                      space);
    NoGCScope no_gc;
    result ^= raw;
    result.set_num_variables(num_variables);
  }
  result.set_isolate(Isolate::Current());
  return result.raw();
}


const char* Context::ToCString() const {
  return "Context";
}


RawContextScope* ContextScope::New(intptr_t num_variables) {
  const Class& context_scope_class =
    Class::Handle(Object::context_scope_class());
  intptr_t size = ContextScope::InstanceSize(num_variables);
  ContextScope& result = ContextScope::Handle();
  {
    RawObject* raw = Object::Allocate(context_scope_class, size, Heap::kOld);
    NoGCScope no_gc;
    result ^= raw;
    result.set_num_variables(num_variables);
  }
  return result.raw();
}


intptr_t ContextScope::TokenIndexAt(intptr_t scope_index) const {
  return Smi::Value(VariableDescAddr(scope_index)->token_index);
}


void ContextScope::SetTokenIndexAt(intptr_t scope_index,
                                   intptr_t token_index) const {
  VariableDescAddr(scope_index)->token_index = Smi::New(token_index);
}


RawString* ContextScope::NameAt(intptr_t scope_index) const {
  return VariableDescAddr(scope_index)->name;
}


void ContextScope::SetNameAt(intptr_t scope_index, const String& name) const {
  VariableDescAddr(scope_index)->name = name.raw();
}


bool ContextScope::IsFinalAt(intptr_t scope_index) const {
  return Bool::Handle(VariableDescAddr(scope_index)->is_final).value();
}


void ContextScope::SetIsFinalAt(intptr_t scope_index, bool is_final) const {
  VariableDescAddr(scope_index)->is_final = Bool::Get(is_final);
}


RawAbstractType* ContextScope::TypeAt(intptr_t scope_index) const {
  return VariableDescAddr(scope_index)->type;
}


void ContextScope::SetTypeAt(
    intptr_t scope_index, const AbstractType& type) const {
  VariableDescAddr(scope_index)->type = type.raw();
}


intptr_t ContextScope::ContextIndexAt(intptr_t scope_index) const {
  return Smi::Value(VariableDescAddr(scope_index)->context_index);
}


void ContextScope::SetContextIndexAt(intptr_t scope_index,
                                     intptr_t context_index) const {
  VariableDescAddr(scope_index)->context_index = Smi::New(context_index);
}


intptr_t ContextScope::ContextLevelAt(intptr_t scope_index) const {
  return Smi::Value(VariableDescAddr(scope_index)->context_level);
}


void ContextScope::SetContextLevelAt(intptr_t scope_index,
                                     intptr_t context_level) const {
  VariableDescAddr(scope_index)->context_level = Smi::New(context_level);
}


const char* ContextScope::ToCString() const {
  return "ContextScope";
}


const char* ICData::ToCString() const {
  const char* kFormat = "ICData target:%s";
  const String& name = String::Handle(target_name());
  intptr_t len = OS::SNPrint(NULL, 0, kFormat, name.ToCString()) + 1;
  char* chars = reinterpret_cast<char*>(
      Isolate::Current()->current_zone()->Allocate(len));
  OS::SNPrint(chars, len, kFormat, name.ToCString());
  return chars;
}


void ICData::set_function(const Function& value) const {
  StorePointer(&raw_ptr()->function_, value.raw());
}


void ICData::set_target_name(const String& value) const {
  StorePointer(&raw_ptr()->target_name_, value.raw());
}


void ICData::set_id(intptr_t value) const {
  raw_ptr()->id_ = value;
}


void ICData::set_num_args_tested(intptr_t value) const {
  raw_ptr()->num_args_tested_ = value;
}


void ICData::set_ic_data(const Array& value) const {
  StorePointer(&raw_ptr()->ic_data_, value.raw());
}


intptr_t ICData::TestEntryLength() const {
  return num_args_tested() + 1 /* target function*/;
}


intptr_t ICData::NumberOfChecks() const {
  // Do not count the sentinel;
  return (Array::Handle(ic_data()).Length() / TestEntryLength()) - 1;
}


void ICData::AddCheck(const GrowableArray<const Class*>& classes,
                      const Function& target) const {
  ASSERT(classes.length() == num_args_tested());
  intptr_t old_num = NumberOfChecks();
  Array& data = Array::Handle(ic_data());
  intptr_t new_len = data.Length() + TestEntryLength();
  data = Array::Grow(data, new_len, Heap::kOld);
  set_ic_data(data);
  intptr_t data_pos = old_num * TestEntryLength();
  for (intptr_t i = 0; i < classes.length(); i++) {
    // Null is used as terminating value, do not add it.
    ASSERT(!classes[i]->IsNull());
    data.SetAt(data_pos++, *(classes[i]));
  }
  ASSERT(!target.IsNull());
  data.SetAt(data_pos, target);
}


void ICData::GetCheckAt(intptr_t index,
                        GrowableArray<const Class*>* classes,
                        Function* target) const {
  ASSERT(classes != NULL);
  ASSERT(target != NULL);
  classes->Clear();
  const Array& data = Array::Handle(ic_data());
  intptr_t data_pos = index * TestEntryLength();
  for (intptr_t i = 0; i < num_args_tested(); i++) {
    Class& cls = Class::ZoneHandle();
    cls ^= data.At(data_pos++);
    classes->Add(&cls);
  }
  (*target) ^= data.At(data_pos);
}


void ICData::GetOneClassCheckAt(
    int index, Class* cls, Function* target) const {
  ASSERT(cls != NULL);
  ASSERT(target != NULL);
  ASSERT(num_args_tested() == 1);
  const Array& data = Array::Handle(ic_data());
  intptr_t data_pos = index * TestEntryLength();
  *cls ^= data.At(data_pos);
  *target ^= data.At(data_pos + 1);
}


RawICData* ICData::New(const Function& function,
                       const String& target_name,
                       intptr_t id,
                       intptr_t num_args_tested) {
  ASSERT(num_args_tested > 0);
  const Class& cls = Class::Handle(Object::icdata_class());
  ASSERT(!cls.IsNull());
  ICData& result = ICData::Handle();
  {
    // IC data objects ar long living objects, allocate them in old generation.
    RawObject* raw =
    Object::Allocate(cls, ICData::InstanceSize(), Heap::kOld);
    NoGCScope no_gc;
    result ^= raw;
  }
  result.set_function(function);
  result.set_target_name(target_name);
  result.set_id(id);
  result.set_num_args_tested(num_args_tested);
  // Number of array elements in one test entry (num_args_tested + 1)
  intptr_t len = result.TestEntryLength();
  // IC data array must be null terminated (sentinel entry).
  const Array& ic_data = Array::Handle(Array::New(len, Heap::kOld));
  result.set_ic_data(ic_data);
  return result.raw();
}


const char* Error::ToErrorCString() const {
  UNREACHABLE();
  return "Internal Error";
}


const char* Error::ToCString() const {
  // Error is an abstract class.  We should never reach here.
  UNREACHABLE();
  return "Error";
}


RawApiError* ApiError::New(const String& message, Heap::Space space) {
  const Class& cls = Class::Handle(Object::api_error_class());
  ApiError& result = ApiError::Handle();
  {
    RawObject* raw = Object::Allocate(cls,
                                      ApiError::InstanceSize(),
                                      space);
    NoGCScope no_gc;
    result ^= raw;
  }
  result.set_message(message);
  return result.raw();
}


void ApiError::set_message(const String& message) const {
  StorePointer(&raw_ptr()->message_, message.raw());
}


const char* ApiError::ToErrorCString() const {
  const String& msg_str = String::Handle(message());
  return msg_str.ToCString();
}


const char* ApiError::ToCString() const {
  return "ApiError";
}


RawLanguageError* LanguageError::New(const String& message, Heap::Space space) {
  const Class& cls = Class::Handle(Object::language_error_class());
  LanguageError& result = LanguageError::Handle();
  {
    RawObject* raw = Object::Allocate(cls,
                                      LanguageError::InstanceSize(),
                                      space);
    NoGCScope no_gc;
    result ^= raw;
  }
  result.set_message(message);
  return result.raw();
}


void LanguageError::set_message(const String& message) const {
  StorePointer(&raw_ptr()->message_, message.raw());
}


const char* LanguageError::ToErrorCString() const {
  const String& msg_str = String::Handle(message());
  return msg_str.ToCString();
}


const char* LanguageError::ToCString() const {
  return "LanguageError";
}


RawUnhandledException* UnhandledException::New(const Instance& exception,
                                               const Instance& stacktrace,
                                               Heap::Space space) {
  const Class& cls = Class::Handle(Object::unhandled_exception_class());
  UnhandledException& result = UnhandledException::Handle();
  {
    RawObject* raw = Object::Allocate(cls,
                                      UnhandledException::InstanceSize(),
                                      space);
    NoGCScope no_gc;
    result ^= raw;
  }
  result.set_exception(exception);
  result.set_stacktrace(stacktrace);
  return result.raw();
}


void UnhandledException::set_exception(const Instance& exception) const {
  StorePointer(&raw_ptr()->exception_, exception.raw());
}


void UnhandledException::set_stacktrace(const Instance& stacktrace) const {
  StorePointer(&raw_ptr()->stacktrace_, stacktrace.raw());
}


const char* UnhandledException::ToErrorCString() const {
  Isolate* isolate = Isolate::Current();
  HANDLESCOPE(isolate);
  Object& strtmp = Object::Handle();

  const Instance& exc = Instance::Handle(exception());
  strtmp = DartLibraryCalls::ToString(exc);
  const char* exc_str =
      "<Received error while converting exception to string>";
  if (!strtmp.IsError()) {
    exc_str = strtmp.ToCString();
  }
  const Instance& stack = Instance::Handle(stacktrace());
  strtmp = DartLibraryCalls::ToString(stack);
  const char* stack_str =
      "<Received error while converting stack trace to string>";
  if (!strtmp.IsError()) {
    stack_str = strtmp.ToCString();
  }

  const char* format = "Unhandled exception:\n%s\n%s";
  int len = (strlen(exc_str) + strlen(stack_str) + strlen(format)
             - 4    // Two '%s'
             + 1);  // '\0'
  char* chars = reinterpret_cast<char*>(isolate->current_zone()->Allocate(len));
  OS::SNPrint(chars, len, format, exc_str, stack_str);
  return chars;
}


const char* UnhandledException::ToCString() const {
  return "UnhandledException";
}


RawUnwindError* UnwindError::New(const String& message, Heap::Space space) {
  const Class& cls = Class::Handle(Object::unwind_error_class());
  UnwindError& result = UnwindError::Handle();
  {
    RawObject* raw = Object::Allocate(cls,
                                      UnwindError::InstanceSize(),
                                      space);
    NoGCScope no_gc;
    result ^= raw;
  }
  result.set_message(message);
  return result.raw();
}


void UnwindError::set_message(const String& message) const {
  StorePointer(&raw_ptr()->message_, message.raw());
}


const char* UnwindError::ToErrorCString() const {
  UNIMPLEMENTED();
  return "UnwindError";
}


const char* UnwindError::ToCString() const {
  return "UnwindError";
}


bool Instance::Equals(const Instance& other) const {
  if (this->raw() == other.raw()) {
    return true;  // "===".
  }

  if (other.IsNull() || (this->clazz() != other.clazz())) {
    return false;
  }

  {
    NoGCScope no_gc;
    // Raw bits compare.
    const intptr_t instance_size = Class::Handle(this->clazz()).instance_size();
    ASSERT(instance_size != 0);
    uword this_addr = reinterpret_cast<uword>(this->raw_ptr());
    uword other_addr = reinterpret_cast<uword>(other.raw_ptr());
    for (intptr_t offset = sizeof(RawObject);
         offset < instance_size;
         offset += kWordSize) {
      if ((*reinterpret_cast<RawObject**>(this_addr + offset)) !=
          (*reinterpret_cast<RawObject**>(other_addr + offset))) {
        return false;
      }
    }
  }
  return true;
}


RawInstance* Instance::Canonicalize() const {
  ASSERT(!IsNull());
  if (!IsCanonical()) {
    const Class& cls = Class::Handle(this->clazz());
    Array& constants = Array::Handle(cls.constants());
    const intptr_t constants_len = constants.Length();
    // Linear search to see whether this value is already present in the
    // list of canonicalized constants.
    Instance& norm_value = Instance::Handle();
    intptr_t index = 0;
    while (index < constants_len) {
      norm_value ^= constants.At(index);
      if (norm_value.IsNull()) {
        break;
      }
      if (this->Equals(norm_value)) {
        return norm_value.raw();
      }
      index++;
    }
    // The value needs to be added to the list. Grow the list if
    // it is full.
    // TODO(srdjan): Copy instance into old space if canonicalized?
    cls.InsertCanonicalConstant(index, *this);
    SetCanonical();
  }
  return this->raw();
}


RawType* Instance::GetType() const {
  if (IsNull()) {
    return Type::NullType();
  }
  const Class& cls = Class::Handle(clazz());
  AbstractTypeArguments& type_arguments = AbstractTypeArguments::Handle();
  if (cls.HasTypeArguments()) {
    type_arguments = GetTypeArguments();
  }
  const Type& type = Type::Handle(
      Type::New(cls, type_arguments, Scanner::kDummyTokenIndex));
  type.set_is_finalized();
  return type.raw();
}


RawAbstractTypeArguments* Instance::GetTypeArguments() const {
  const Class& cls = Class::Handle(clazz());
  intptr_t field_offset = cls.type_arguments_instance_field_offset();
  ASSERT(field_offset != Class::kNoTypeArguments);
  AbstractTypeArguments& type_arguments = AbstractTypeArguments::Handle();
  type_arguments ^= *FieldAddrAtOffset(field_offset);
  return type_arguments.raw();
}


void Instance::SetTypeArguments(const AbstractTypeArguments& value) const {
  const Class& cls = Class::Handle(clazz());
  intptr_t field_offset = cls.type_arguments_instance_field_offset();
  ASSERT(field_offset != Class::kNoTypeArguments);
  *FieldAddrAtOffset(field_offset) = value.Canonicalize();
}


bool Instance::IsInstanceOf(const AbstractType& other,
                            const AbstractTypeArguments& other_instantiator,
                            Error* malformed_error) const {
  ASSERT(other.IsFinalized());
  ASSERT(!other.IsDynamicType());
  ASSERT(!other.IsVoidType());
  if (IsNull()) {
    Class& other_class = Class::Handle();
    if (other.IsTypeParameter()) {
      if (other_instantiator.IsNull()) {
        return true;  // Other type is uninstantiated, i.e. Dynamic.
      }
      const AbstractType& instantiated_other =
          AbstractType::Handle(other_instantiator.TypeAt(other.Index()));
      ASSERT(instantiated_other.IsInstantiated());
      other_class = instantiated_other.type_class();
    } else {
      other_class = other.type_class();
    }
    return other_class.IsObjectClass() || other_class.IsDynamicClass();
  }
  const Class& cls = Class::Handle(clazz());
  // We must not encounter Object::sentinel() or Object::transition_sentinel(),
  // both instances of class NullClass, but not instance Object::null().
  ASSERT(!cls.IsNullClass());
  AbstractTypeArguments& type_arguments = AbstractTypeArguments::Handle();
  const intptr_t num_type_arguments = cls.NumTypeArguments();
  if (num_type_arguments > 0) {
    type_arguments = GetTypeArguments();
    // Verify that the number of type arguments in the instance matches the
    // number of type arguments expected by the instance class.
    // A discrepancy is allowed for closures, which borrow the type argument
    // vector of their instantiator, which may be of a super class of the class
    // defining the closure. Truncating the vector to the correct length on
    // instantiation is unnecessary. The vector may therefore be longer.
    ASSERT(type_arguments.IsNull() ||
           (type_arguments.Length() == num_type_arguments) ||
           (cls.IsSignatureClass() &&
            (type_arguments.Length() > num_type_arguments)));
  }
  Class& other_class = Class::Handle();
  AbstractTypeArguments& other_type_arguments = AbstractTypeArguments::Handle();
  // In case 'other' is not instantiated, we could simply call
  // other.InstantiateFrom(other_instantiator), however, we can save the
  // allocation of a new AbstractType by inlining the code.
  if (other.IsTypeParameter()) {
    if (other_instantiator.IsNull()) {
      // An uninstantiated type parameter is equivalent to Dynamic.
      return true;
    }
    AbstractType& instantiated_other = AbstractType::Handle(
        other_instantiator.TypeAt(other.Index()));
    if (instantiated_other.IsDynamicType() ||
        instantiated_other.IsTypeParameter()) {
      return true;
    }
    other_class = instantiated_other.type_class();
    other_type_arguments = instantiated_other.arguments();
  } else {
    other_class = other.type_class();
    other_type_arguments = other.arguments();
    if (!other_type_arguments.IsNull() &&
        !other_type_arguments.IsInstantiated()) {
      other_type_arguments =
          other_type_arguments.InstantiateFrom(other_instantiator);
    }
  }
  return cls.IsSubtypeOf(type_arguments, other_class, other_type_arguments,
                         malformed_error);
}


bool Instance::IsValidNativeIndex(int index) const {
  const Class& cls = Class::Handle(clazz());
  return (index >= 0 && index < cls.num_native_fields());
}


RawInstance* Instance::New(const Class& cls, Heap::Space space) {
  Instance& result = Instance::Handle();
  {
    intptr_t instance_size = cls.instance_size();
    ASSERT(instance_size > 0);
    RawObject* raw = Object::Allocate(cls, instance_size, space);
    NoGCScope no_gc;
    result ^= raw;
    uword addr = reinterpret_cast<uword>(result.raw_ptr());
    // Initialize fields.
    intptr_t offset = sizeof(RawObject);
    // Initialize all native fields to NULL.
    for (intptr_t i = 0; i < cls.num_native_fields(); i++) {
      *reinterpret_cast<uword*>(addr + offset) = 0;
      offset += kWordSize;
    }
  }
  return result.raw();
}


bool Instance::IsValidFieldOffset(int offset) const {
  const Class& cls = Class::Handle(clazz());
  return (offset >= 0 && offset <= (cls.instance_size() - kWordSize));
}


const char* Instance::ToCString() const {
  if (IsNull()) {
    return "null";
  } else if (raw() == Object::sentinel()) {
    return "sentinel";
  } else if (raw() == Object::transition_sentinel()) {
    return "transition_sentinel";
  } else if (Isolate::Current()->no_gc_scope_depth() > 0) {
    // Can occur when running disassembler.
    return "Instance";
  } else {
    const char* kFormat = "Instance of '%s'";
    Class& cls = Class::Handle(clazz());
    AbstractTypeArguments& type_arguments = AbstractTypeArguments::Handle();
    const intptr_t num_type_arguments = cls.NumTypeArguments();
    if (num_type_arguments > 0) {
      type_arguments = GetTypeArguments();
    }
    const Type& type =
        Type::Handle(Type::New(cls, type_arguments, Scanner::kDummyTokenIndex));
    const String& type_name = String::Handle(type.Name());
    // Calculate the size of the string.
    intptr_t len = OS::SNPrint(NULL, 0, kFormat, type_name.ToCString()) + 1;
    char* chars = reinterpret_cast<char*>(
        Isolate::Current()->current_zone()->Allocate(len));
    OS::SNPrint(chars, len, kFormat, type_name.ToCString());
    return chars;
  }
}


const char* Number::ToCString() const {
  // Number is an interface. No instances of Number should exist.
  UNREACHABLE();
  return "Number";
}


const char* Integer::ToCString() const {
  // Integer is an interface. No instances of Integer should exist.
  UNREACHABLE();
  return "Integer";
}


RawInteger* Integer::New(const String& str) {
  const Bigint& big = Bigint::Handle(Bigint::New(str));
  if (BigintOperations::FitsIntoSmi(big)) {
    return BigintOperations::ToSmi(big);
  } else if (BigintOperations::FitsIntoMint(big)) {
    return Mint::New(BigintOperations::ToMint(big));
  } else {
    return big.raw();
  }
}


RawInteger* Integer::New(int64_t value) {
  if ((value <= Smi::kMaxValue) && (value >= Smi::kMinValue)) {
    return Smi::New(value);
  }
  return Mint::New(value);
}


double Integer::AsDoubleValue() const {
  UNIMPLEMENTED();
  return 0.0;
}


int64_t Integer::AsInt64Value() const {
  UNIMPLEMENTED();
  return 0;
}


int Integer::CompareWith(const Integer& other) const {
  UNIMPLEMENTED();
  return 0;
}


bool Smi::Equals(const Instance& other) const {
  if (other.IsNull() || !other.IsSmi()) {
    return false;
  }

  Smi& other_smi = Smi::Handle();
  other_smi ^= other.raw();
  return (this->Value() == other_smi.Value());
}


double Smi::AsDoubleValue() const {
  return static_cast<double>(this->Value());
}


int64_t Smi::AsInt64Value() const {
  return this->Value();
}


static bool FitsIntoSmi(const Integer& integer) {
  if (integer.IsSmi()) {
    return true;
  }
  if (integer.IsMint()) {
    int64_t mint_value = integer.AsInt64Value();
    return Smi::IsValid64(mint_value);
  }
  if (integer.IsBigint()) {
    Bigint& big = Bigint::Handle();
    big ^= integer.raw();
    return BigintOperations::FitsIntoSmi(big);
  }
  UNREACHABLE();
  return false;
}


int Smi::CompareWith(const Integer& other) const {
  if (other.IsSmi()) {
    Smi& smi = Smi::Handle();
    smi ^= other.raw();
    if (this->Value() < smi.Value()) {
      return -1;
    } else if (this->Value() > smi.Value()) {
      return 1;
    } else {
      return 0;
    }
  }
  ASSERT(!FitsIntoSmi(other));
  if (other.IsMint() || other.IsBigint()) {
    if (this->IsNegative() == other.IsNegative()) {
      return this->IsNegative() ? 1 : -1;
    }
    return this->IsNegative() ? -1 : 1;
  }
  UNREACHABLE();
  return 0;
}


const char* Smi::ToCString() const {
  const char* kFormat = "%ld";
  // Calculate the size of the string.
  intptr_t len = OS::SNPrint(NULL, 0, kFormat, Value()) + 1;
  char* chars = reinterpret_cast<char*>(
      Isolate::Current()->current_zone()->Allocate(len));
  OS::SNPrint(chars, len, kFormat, Value());
  return chars;
}


RawClass* Smi::Class() {
  return Isolate::Current()->object_store()->smi_class();
}


void Mint::set_value(int64_t value) const {
  raw_ptr()->value_ = value;
}


RawMint* Mint::New(int64_t val, Heap::Space space) {
  // Do not allocate a Mint if Smi would do.
  ASSERT(!Smi::IsValid64(val));
  Isolate* isolate = Isolate::Current();
  const Class& cls =
      Class::Handle(isolate->object_store()->mint_class());
  Mint& result = Mint::Handle();
  {
    RawObject* raw = Object::Allocate(cls, Mint::InstanceSize(), space);
    NoGCScope no_gc;
    result ^= raw;
  }
  result.set_value(val);
  return result.raw();
}


RawMint* Mint::NewCanonical(int64_t value) {
  // Do not allocate a Mint if Smi would do.
  ASSERT(!Smi::IsValid64(value));
  const Class& cls =
      Class::Handle(Isolate::Current()->object_store()->mint_class());
  const Array& constants = Array::Handle(cls.constants());
  const intptr_t constants_len = constants.Length();
  // Linear search to see whether this value is already present in the
  // list of canonicalized constants.
  Mint& canonical_value = Mint::Handle();
  intptr_t index = 0;
  while (index < constants_len) {
    canonical_value ^= constants.At(index);
    if (canonical_value.IsNull()) {
      break;
    }
    if (canonical_value.value() == value) {
      return canonical_value.raw();
    }
    index++;
  }
  // The value needs to be added to the constants list. Grow the list if
  // it is full.
  canonical_value = Mint::New(value, Heap::kOld);
  cls.InsertCanonicalConstant(index, canonical_value);
  canonical_value.SetCanonical();
  return canonical_value.raw();
}


bool Mint::Equals(const Instance& other) const {
  if (this->raw() == other.raw()) {
    // Both handles point to the same raw instance.
    return true;
  }

  if (!other.IsMint() || other.IsNull()) {
    return false;
  }

  Mint& other_mint = Mint::Handle();
  other_mint ^= other.raw();

  return value() == other_mint.value();
}


double Mint::AsDoubleValue() const {
  return static_cast<double>(this->value());
}


int64_t Mint::AsInt64Value() const {
  return this->value();
}


int Mint::CompareWith(const Integer& other) const {
  ASSERT(!FitsIntoSmi(*this));
  if (other.IsMint() || other.IsSmi()) {
    int64_t a = AsInt64Value();
    int64_t b = other.AsInt64Value();
    if (a < b) {
      return -1;
    } else if (a > b) {
      return 1;
    } else {
      return 0;
    }
  }
  if (other.IsBigint()) {
    Bigint& bigi = Bigint::Handle();
    bigi ^= other.raw();
    ASSERT(!BigintOperations::FitsIntoMint(bigi));
    if (this->IsNegative() == other.IsNegative()) {
      return this->IsNegative() ? 1 : -1;
    }
    return this->IsNegative() ? -1 : 1;
  }
  UNREACHABLE();
  return 0;
}


const char* Mint::ToCString() const {
  const char* kFormat = "%lld";
  // Calculate the size of the string.
  intptr_t len = OS::SNPrint(NULL, 0, kFormat, value()) + 1;
  char* chars = reinterpret_cast<char*>(
      Isolate::Current()->current_zone()->Allocate(len));
  OS::SNPrint(chars, len, kFormat, value());
  return chars;
}


void Double::set_value(double value) const {
  raw_ptr()->value_ = value;
}


bool Double::EqualsToDouble(double value) const {
  intptr_t value_offset = Double::value_offset();
  void* this_addr = reinterpret_cast<void*>(
      reinterpret_cast<uword>(this->raw_ptr()) + value_offset);
  void* other_addr = reinterpret_cast<void*>(&value);
  return (memcmp(this_addr, other_addr, sizeof(value)) == 0);
}


bool Double::Equals(const Instance& other) const {
  if (this->raw() == other.raw()) {
    return true;  // "===".
  }
  if (other.IsNull() || !other.IsDouble()) {
    return false;
  }
  Double& other_dbl = Double::Handle();
  other_dbl ^= other.raw();
  return EqualsToDouble(other_dbl.value());
}


RawDouble* Double::New(double d, Heap::Space space) {
  Isolate* isolate = Isolate::Current();
  const Class& cls =
      Class::Handle(isolate->object_store()->double_class());
  Double& result = Double::Handle();
  {
    RawObject* raw = Object::Allocate(cls, Double::InstanceSize(), space);
    NoGCScope no_gc;
    result ^= raw;
  }
  result.set_value(d);
  return result.raw();
}


static bool IsWhiteSpace(char ch) {
  return ch == '\0' || ch == '\n' || ch == '\r' || ch == ' ' || ch == '\t';
}


static bool StringToDouble(const String& str, double* double_value) {
  ASSERT(double_value != NULL);
  // TODO(regis): For now, we use strtod to convert a string to double.
  const char* nptr = str.ToCString();
  char* endptr = NULL;
  *double_value = strtod(nptr, &endptr);
  // We do not treat overflow or underflow as an error and therefore do not
  // check errno for ERANGE.
  if (!IsWhiteSpace(*endptr)) {
    return false;
  }
  return true;
}


RawDouble* Double::New(const String& str, Heap::Space space) {
  double double_value;
  if (!StringToDouble(str, &double_value)) {
    return Double::Handle().raw();
  }
  return New(double_value, space);
}


RawDouble* Double::NewCanonical(double value) {
  const Class& cls =
      Class::Handle(Isolate::Current()->object_store()->double_class());
  const Array& constants = Array::Handle(cls.constants());
  const intptr_t constants_len = constants.Length();
  // Linear search to see whether this value is already present in the
  // list of canonicalized constants.
  Double& canonical_value = Double::Handle();
  intptr_t index = 0;
  while (index < constants_len) {
    canonical_value ^= constants.At(index);
    if (canonical_value.IsNull()) {
      break;
    }
    if (canonical_value.EqualsToDouble(value)) {
      return canonical_value.raw();
    }
    index++;
  }
  // The value needs to be added to the constants list. Grow the list if
  // it is full.
  canonical_value = Double::New(value, Heap::kOld);
  cls.InsertCanonicalConstant(index, canonical_value);
  canonical_value.SetCanonical();
  return canonical_value.raw();
}


RawDouble* Double::NewCanonical(const String& str) {
  double double_value;
  if (!StringToDouble(str, &double_value)) {
    return Double::Handle().raw();
  }
  return NewCanonical(double_value);
}


const char* Double::ToCString() const {
  if (isnan(value())) {
    return "NaN";
  }
  if (isinf(value())) {
    return value() < 0 ? "-Infinity" : "Infinity";
  }
  const int kBufferSize = 128;
  char* buffer = reinterpret_cast<char*>(
      Isolate::Current()->current_zone()->Allocate(kBufferSize));
  buffer[kBufferSize - 1] = '\0';
  DoubleToCString(value(), buffer, kBufferSize);
  return buffer;
}


bool Bigint::Equals(const Instance& other) const {
  if (this->raw() == other.raw()) {
    // Both handles point to the same raw instance.
    return true;
  }

  if (!other.IsBigint() || other.IsNull()) {
    return false;
  }

  Bigint& other_bgi = Bigint::Handle();
  other_bgi ^= other.raw();

  intptr_t len = this->Length();
  if (len != other_bgi.Length()) {
    return false;
  }

  for (intptr_t i = 0; i < len; i++) {
    if (this->GetChunkAt(i) != other_bgi.GetChunkAt(i)) {
      return false;
    }
  }
  return true;
}


RawBigint* Bigint::New(const String& str, Heap::Space space) {
  return BigintOperations::NewFromCString(str.ToCString(), space);
}


RawBigint* Bigint::New(int64_t value, Heap::Space space) {
  return BigintOperations::NewFromInt64(value, space);
}


double Bigint::AsDoubleValue() const {
  return Double::Handle(BigintOperations::ToDouble(*this)).value();
}


int64_t Bigint::AsInt64Value() const {
  if (!BigintOperations::FitsIntoMint(*this)) {
    UNREACHABLE();
  }
  return BigintOperations::ToMint(*this);
}


// For positive values: Smi < Mint < Bigint.
int Bigint::CompareWith(const Integer& other) const {
  ASSERT(!FitsIntoSmi(*this));
  ASSERT(!BigintOperations::FitsIntoMint(*this));
  if (other.IsBigint()) {
    Bigint& big = Bigint::Handle();
    big ^= other.raw();
    return BigintOperations::Compare(*this, big);
  }
  if (this->IsNegative() == other.IsNegative()) {
    return this->IsNegative() ? -1 : 1;
  }
  return this->IsNegative() ? -1 : 1;
}


RawBigint* Bigint::Allocate(intptr_t length, Heap::Space space) {
  ASSERT(length >= 0);
  Isolate* isolate = Isolate::Current();
  const Class& cls = Class::Handle(isolate->object_store()->bigint_class());
  Bigint& result = Bigint::Handle();
  {
    RawObject* raw = Object::Allocate(cls, Bigint::InstanceSize(length), space);
    NoGCScope no_gc;
    result ^= raw;
    result.raw_ptr()->allocated_length_ = length;  // Chunk length allocated.
    result.raw_ptr()->signed_length_ = length;  // Chunk length in use.
  }
  return result.raw();
}


static uword ZoneAllocator(intptr_t size) {
  Zone* zone = Isolate::Current()->current_zone();
  return zone->Allocate(size);
}


const char* Bigint::ToCString() const {
  return BigintOperations::ToDecimalCString(*this, &ZoneAllocator);
}


class StringHasher : ValueObject {
 public:
  StringHasher() : hash_(0) {}
  void Add(int32_t ch) {
    hash_ += ch;
    hash_ += hash_ << 10;
    hash_ ^= hash_ >> 6;
  }
  // Return a non-zero hash of at most 'bits' bits.
  intptr_t Finalize(int bits) {
    ASSERT(1 <= bits && bits <= (kBitsPerWord - 1));
    hash_ += hash_ << 3;
    hash_ ^= hash_ >> 11;
    hash_ += hash_ << 15;
    hash_ = hash_ & ((static_cast<intptr_t>(1) << bits) - 1);
    ASSERT(hash_ >= 0);
    return hash_ == 0 ? 1 : hash_;
  }
 private:
  intptr_t hash_;
};


intptr_t String::Hash() const {
  intptr_t result = Smi::Value(raw_ptr()->hash_);
  if (result != 0) {
    return result;
  }
  result = String::Hash(*this, 0, this->Length());
  this->SetHash(result);
  return result;
}


intptr_t String::Hash(const String& str, intptr_t begin_index, intptr_t len) {
  ASSERT(begin_index >= 0);
  ASSERT(len >= 0);
  ASSERT((begin_index + len) <= str.Length());
  StringHasher hasher;
  for (intptr_t i = 0; i < len; i++) {
    hasher.Add(str.CharAt(begin_index + i));
  }
  return hasher.Finalize(String::kHashBits);
}


template<typename T>
static intptr_t HashImpl(const T* characters, intptr_t len) {
  ASSERT(len >= 0);
  StringHasher hasher;
  for (intptr_t i = 0; i < len; i++) {
    hasher.Add(characters[i]);
  }
  return hasher.Finalize(String::kHashBits);
}


intptr_t String::Hash(const uint8_t* characters, intptr_t len) {
  return HashImpl(characters, len);
}


intptr_t String::Hash(const uint16_t* characters, intptr_t len) {
  return HashImpl(characters, len);
}


intptr_t String::Hash(const uint32_t* characters, intptr_t len) {
  return HashImpl(characters, len);
}


int32_t String::CharAt(intptr_t index) const {
  // String is an abstract class.
  UNREACHABLE();
  return 0;
}


intptr_t String::CharSize() const {
  // String is an abstract class.
  UNREACHABLE();
  return 0;
}


bool String::Equals(const Instance& other) const {
  if (this->raw() == other.raw()) {
    // Both handles point to the same raw instance.
    return true;
  }

  if (!other.IsString() || other.IsNull()) {
    return false;
  }

  String& other_string = String::Handle();
  other_string ^= other.raw();
  if (this->HasHash() && other_string.HasHash() &&
      (this->Hash() != other_string.Hash())) {
    // Both sides have a hash code and it does not match.
    return false;
  }

  intptr_t len = this->Length();
  if (len != other_string.Length()) {
    // Lengths don't match.
    return false;
  }

  for (intptr_t i = 0; i < len; i++) {
    if (this->CharAt(i) != other_string.CharAt(i)) {
      return false;
    }
  }
  return true;
}


bool String::Equals(const String& str,
                    intptr_t begin_index,
                    intptr_t len) const {
  ASSERT(begin_index >= 0);
  ASSERT(begin_index == 0 || begin_index < str.Length());
  ASSERT(len >= 0);
  ASSERT(len <= str.Length());
  if (len != this->Length()) {
    // Lengths don't match.
    return false;
  }

  for (intptr_t i = 0; i < len; i++) {
    if (this->CharAt(i) != str.CharAt(begin_index + i)) {
      return false;
    }
  }
  return true;
}


bool String::Equals(const char* str) const {
  for (intptr_t i = 0; i < this->Length(); ++i) {
    if (*str == '\0') {
      // Lengths don't match.
      return false;
    }
    int32_t ch;
    intptr_t consumed = Utf8::Decode(str, &ch);
    if (consumed == 0 || this->CharAt(i) != ch) {
      return false;
    }
    str += consumed;
  }
  return *str == '\0';
}


bool String::Equals(const uint8_t* characters, intptr_t len) const {
  if (len != this->Length()) {
    // Lengths don't match.
    return false;
  }

  for (intptr_t i = 0; i < len; i++) {
    if (this->CharAt(i) != characters[i]) {
      return false;
    }
  }
  return true;
}


bool String::Equals(const uint16_t* characters, intptr_t len) const {
  if (len != this->Length()) {
    // Lengths don't match.
    return false;
  }

  for (intptr_t i = 0; i < len; i++) {
    if (this->CharAt(i) != characters[i]) {
      return false;
    }
  }
  return true;
}


bool String::Equals(const uint32_t* characters, intptr_t len) const {
  if (len != this->Length()) {
    // Lengths don't match.
    return false;
  }

  for (intptr_t i = 0; i < len; i++) {
    if (this->CharAt(i) != static_cast<int32_t>(characters[i])) {
      return false;
    }
  }
  return true;
}


intptr_t String::CompareTo(const String& other) const {
  const intptr_t this_len = this->Length();
  const intptr_t other_len = other.IsNull() ? 0 : other.Length();
  const intptr_t len = (this_len < other_len) ? this_len : other_len;
  for (intptr_t i = 0; i < len; i++) {
    int32_t this_code_point = this->CharAt(i);
    int32_t other_code_point = other.CharAt(i);
    if (this_code_point < other_code_point) {
      return -1;
    }
    if (this_code_point > other_code_point) {
      return 1;
    }
  }
  if (this_len < other_len) return -1;
  if (this_len > other_len) return 1;
  return 0;
}


bool String::StartsWith(const String& other) const {
  if (other.IsNull() || (other.Length() > this->Length())) {
    return false;
  }
  intptr_t slen = other.Length();
  for (int i = 0; i < slen; i++) {
    if (this->CharAt(i) != other.CharAt(i)) {
      return false;
    }
  }
  return true;
}


RawInstance* String::Canonicalize() const {
  if (IsCanonical()) {
    return this->raw();
  }
  return NewSymbol(*this);
}


RawString* String::New(const char* str, Heap::Space space) {
  intptr_t width = 0;
  intptr_t len = Utf8::CodePointCount(str, &width);
  if (width == 1) {
    const OneByteString& onestr
        = OneByteString::Handle(OneByteString::New(len, space));
    if (len > 0) {
      NoGCScope no_gc;
      Utf8::Decode(str, onestr.CharAddr(0), len);
    }
    return onestr.raw();
  } else if (width == 2) {
    const TwoByteString& twostr =
        TwoByteString::Handle(TwoByteString::New(len, space));
    NoGCScope no_gc;
    Utf8::Decode(str, twostr.CharAddr(0), len);
    return twostr.raw();
  }
  ASSERT(width == 4);
  const FourByteString& fourstr =
      FourByteString::Handle(FourByteString::New(len, space));
  NoGCScope no_gc;
  Utf8::Decode(str, fourstr.CharAddr(0), len);
  return fourstr.raw();
}


RawString* String::New(const uint8_t* characters,
                       intptr_t len,
                       Heap::Space space) {
  return OneByteString::New(characters, len, space);
}


RawString* String::New(const uint16_t* characters,
                       intptr_t len,
                       Heap::Space space) {
  bool is_one_byte_string = true;
  for (intptr_t i = 0; i < len; ++i) {
    if (characters[i] > 0xFF) {
      is_one_byte_string = false;
      break;
    }
  }
  if (is_one_byte_string) {
    return OneByteString::New(characters, len, space);
  }
  return TwoByteString::New(characters, len, space);
}


RawString* String::New(const uint32_t* characters,
                       intptr_t len,
                       Heap::Space space) {
  bool is_one_byte_string = true;
  bool is_two_byte_string = true;
  for (intptr_t i = 0; i < len; ++i) {
    if (characters[i] > 0xFFFF) {
      is_two_byte_string = false;
      is_one_byte_string = false;
      break;
    } else if (characters[i] > 0xFF) {
      is_one_byte_string = false;
    }
  }
  if (is_one_byte_string) {
    return OneByteString::New(characters, len, space);
  } else if (is_two_byte_string) {
    return TwoByteString::New(characters, len, space);
  }
  return FourByteString::New(characters, len, space);
}


RawString* String::New(const String& str, Heap::Space space) {
  // Currently this just creates a copy of the string in the correct space.
  // Once we have external string support, this will also create a heap copy of
  // the string if necessary. Some optimizations are possible, such as not
  // copying internal strings into the same space.
  intptr_t len = str.Length();
  String& result = String::Handle();
  intptr_t char_size = str.CharSize();
  if (char_size == kOneByteChar) {
    result ^= OneByteString::New(len, space);
  } else if (char_size == kTwoByteChar) {
    result ^= TwoByteString::New(len, space);
  } else {
    ASSERT(char_size == kFourByteChar);
    result ^= FourByteString::New(len, space);
  }
  String::Copy(result, 0, str, 0, len);
  return result.raw();
}


RawString* String::NewExternal(const uint8_t* characters,
                               intptr_t len,
                               void* peer,
                               Dart_PeerFinalizer callback,
                               Heap::Space space) {
  return ExternalOneByteString::New(characters, len, peer, callback, space);
}


RawString* String::NewExternal(const uint16_t* characters,
                               intptr_t len,
                               void* peer,
                               Dart_PeerFinalizer callback,
                               Heap::Space space) {
  return ExternalTwoByteString::New(characters, len, peer, callback, space);
}


RawString* String::NewExternal(const uint32_t* characters,
                               intptr_t len,
                               void* peer,
                               Dart_PeerFinalizer callback,
                               Heap::Space space) {
  return ExternalFourByteString::New(characters, len, peer, callback, space);
}


void String::Copy(const String& dst, intptr_t dst_offset,
                  const uint8_t* characters,
                  intptr_t len) {
  ASSERT(dst_offset >= 0);
  ASSERT(len >= 0);
  ASSERT(len <= (dst.Length() - dst_offset));
  if (dst.IsOneByteString()) {
    OneByteString& onestr = OneByteString::Handle();
    onestr ^= dst.raw();
    NoGCScope no_gc;
    if (len > 0) {
      memmove(onestr.CharAddr(dst_offset), characters, len);
    }
  } else if (dst.IsTwoByteString()) {
    TwoByteString& twostr = TwoByteString::Handle();
    twostr ^= dst.raw();
    NoGCScope no_gc;
    for (intptr_t i = 0; i < len; ++i) {
      *twostr.CharAddr(i + dst_offset) = characters[i];
    }
  } else {
    ASSERT(dst.IsFourByteString());
    FourByteString& fourstr = FourByteString::Handle();
    fourstr ^= dst.raw();
    NoGCScope no_gc;
    for (intptr_t i = 0; i < len; ++i) {
      *fourstr.CharAddr(i + dst_offset) = characters[i];
    }
  }
}


void String::Copy(const String& dst, intptr_t dst_offset,
                  const uint16_t* characters,
                  intptr_t len) {
  ASSERT(dst_offset >= 0);
  ASSERT(len >= 0);
  ASSERT(len <= (dst.Length() - dst_offset));
  if (dst.IsOneByteString()) {
    OneByteString& onestr = OneByteString::Handle();
    onestr ^= dst.raw();
    NoGCScope no_gc;
    for (intptr_t i = 0; i < len; ++i) {
      ASSERT(characters[i] <= 0xFF);
      *onestr.CharAddr(i + dst_offset) = characters[i];
    }
  } else if (dst.IsTwoByteString()) {
    TwoByteString& twostr = TwoByteString::Handle();
    twostr ^= dst.raw();
    NoGCScope no_gc;
    if (len > 0) {
      memmove(twostr.CharAddr(dst_offset), characters, len * 2);
    }
  } else {
    ASSERT(dst.IsFourByteString());
    FourByteString& fourstr = FourByteString::Handle();
    fourstr ^= dst.raw();
    NoGCScope no_gc;
    for (intptr_t i = 0; i < len; ++i) {
      *fourstr.CharAddr(i + dst_offset) = characters[i];
    }
  }
}


void String::Copy(const String& dst, intptr_t dst_offset,
                  const uint32_t* characters,
                  intptr_t len) {
  ASSERT(dst_offset >= 0);
  ASSERT(len >= 0);
  ASSERT(len <= (dst.Length() - dst_offset));
  if (dst.IsOneByteString()) {
    OneByteString& onestr = OneByteString::Handle();
    onestr ^= dst.raw();
    NoGCScope no_gc;
    for (intptr_t i = 0; i < len; ++i) {
      ASSERT(characters[i] <= 0xFF);
      *onestr.CharAddr(i + dst_offset) = characters[i];
    }
  } else if (dst.IsTwoByteString()) {
    TwoByteString& twostr = TwoByteString::Handle();
    twostr ^= dst.raw();
    NoGCScope no_gc;
    for (intptr_t i = 0; i < len; ++i) {
      ASSERT(characters[i] <= 0xFFFF);
      *twostr.CharAddr(i + dst_offset) = characters[i];
    }
  } else {
    ASSERT(dst.IsFourByteString());
    FourByteString& fourstr = FourByteString::Handle();
    fourstr ^= dst.raw();
    NoGCScope no_gc;
    if (len > 0) {
      memmove(fourstr.CharAddr(dst_offset), characters, len * 4);
    }
  }
}


void String::Copy(const String& dst, intptr_t dst_offset,
                  const String& src, intptr_t src_offset,
                  intptr_t len) {
  ASSERT(dst_offset >= 0);
  ASSERT(src_offset >= 0);
  ASSERT(len >= 0);
  ASSERT(len <= (dst.Length() - dst_offset));
  ASSERT(len <= (src.Length() - src_offset));
  if (len > 0) {
    intptr_t char_size = src.CharSize();
    if (char_size == kOneByteChar) {
      if (src.IsOneByteString()) {
        OneByteString& onestr = OneByteString::Handle();
        onestr ^= src.raw();
        NoGCScope no_gc;
        String::Copy(dst, dst_offset, onestr.CharAddr(0) + src_offset, len);
      } else {
        ASSERT(src.IsExternalOneByteString());
        ExternalOneByteString& onestr = ExternalOneByteString::Handle();
        onestr ^= src.raw();
        NoGCScope no_gc;
        String::Copy(dst, dst_offset, onestr.CharAddr(0) + src_offset, len);
      }
    } else if (char_size == kTwoByteChar) {
      if (src.IsTwoByteString()) {
        TwoByteString& twostr = TwoByteString::Handle();
        twostr ^= src.raw();
        NoGCScope no_gc;
        String::Copy(dst, dst_offset, twostr.CharAddr(0) + src_offset, len);
      } else {
        ASSERT(src.IsExternalTwoByteString());
        ExternalTwoByteString& twostr = ExternalTwoByteString::Handle();
        twostr ^= src.raw();
        NoGCScope no_gc;
        String::Copy(dst, dst_offset, twostr.CharAddr(0) + src_offset, len);
      }
    } else {
      ASSERT(char_size == kFourByteChar);
      if (src.IsFourByteString()) {
        FourByteString& fourstr = FourByteString::Handle();
        fourstr ^= src.raw();
        NoGCScope no_gc;
        String::Copy(dst, dst_offset, fourstr.CharAddr(0) + src_offset, len);
      } else {
        ASSERT(src.IsExternalFourByteString());
        ExternalFourByteString& fourstr = ExternalFourByteString::Handle();
        fourstr ^= src.raw();
        NoGCScope no_gc;
        String::Copy(dst, dst_offset, fourstr.CharAddr(0) + src_offset, len);
      }
    }
  }
}


static void GrowSymbolTable(const Array& symbol_table, intptr_t table_size) {
  // TODO(iposva): Avoid exponential growth.
  intptr_t new_table_size = table_size * 2;
  Array& new_symbol_table = Array::Handle(Array::New(new_table_size + 1));
  // Copy all elements from the original symbol table to the newly allocated
  // array.
  String& element = String::Handle();
  Object& new_element = Object::Handle();
  for (intptr_t i = 0; i < table_size; i++) {
    element ^= symbol_table.At(i);
    if (!element.IsNull()) {
      intptr_t hash = element.Hash();
      intptr_t index = hash % new_table_size;
      new_element = new_symbol_table.At(index);
      while (!new_element.IsNull()) {
        index = (index + 1) % new_table_size;  // Move to next element.
        new_element = new_symbol_table.At(index);
      }
      new_symbol_table.SetAt(index, element);
    }
  }
  // Copy used count.
  new_element = symbol_table.At(table_size);
  new_symbol_table.SetAt(new_table_size, new_element);
  // Remember the new symbol table now.
  Isolate::Current()->object_store()->set_symbol_table(new_symbol_table);
}


static void InsertIntoSymbolTable(const Array& symbol_table,
                                  const String& symbol,
                                  intptr_t index,
                                  intptr_t table_size) {
  symbol.SetCanonical();  // Mark object as being canonical.
  symbol_table.SetAt(index, symbol);  // Remember the new symbol.
  Smi& used = Smi::Handle();
  used ^= symbol_table.At(table_size);
  intptr_t used_elements = used.Value() + 1;  // One more element added.
  used = Smi::New(used_elements);
  symbol_table.SetAt(table_size, used);  // Update used count.

  // Rehash if symbol_table is 75% full.
  if (used_elements > ((table_size / 4) * 3)) {
    GrowSymbolTable(symbol_table, table_size);
  }
}


RawString* String::NewSymbol(const char* str) {
  intptr_t width = 0;
  intptr_t len = Utf8::CodePointCount(str, &width);
  intptr_t size = len * width;
  Zone* zone = Isolate::Current()->current_zone();
  if (len == 0) {
    return String::NewSymbol(reinterpret_cast<uint8_t*>(NULL), 0);
  } else if (width == 1) {
    uint8_t* characters = reinterpret_cast<uint8_t*>(zone->Allocate(size));
    Utf8::Decode(str, characters, len);
    return NewSymbol(characters, len);
  } else if (width == 2) {
    uint16_t* characters = reinterpret_cast<uint16_t*>(zone->Allocate(size));
    Utf8::Decode(str, characters, len);
    return NewSymbol(characters, len);
  }
  ASSERT(width == 4);
  uint32_t* characters = reinterpret_cast<uint32_t*>(zone->Allocate(size));
  Utf8::Decode(str, characters, len);
  return NewSymbol(characters, len);
}


template<typename T>
RawString* String::NewSymbol(const T* characters, intptr_t len) {
  Isolate* isolate = Isolate::Current();

  // Calculate the String hash for this sequence of characters.
  intptr_t hash = Hash(characters, len);

  const Array& symbol_table =
      Array::Handle(isolate, isolate->object_store()->symbol_table());
  // Last element of the array is the number of used elements.
  intptr_t table_size = symbol_table.Length() - 1;
  intptr_t index = hash % table_size;

  String& symbol = String::Handle(isolate, String::null());
  symbol ^= symbol_table.At(index);
  while (!symbol.IsNull() && !symbol.Equals(characters, len)) {
    index = (index + 1) % table_size;  // Move to next element.
    symbol ^= symbol_table.At(index);
  }
  // Since we leave enough room in the table to guarantee, that we find an
  // empty spot, index is the insertion point if symbol is null.
  if (symbol.IsNull()) {
    // Allocate new result string.
    symbol = String::New(characters, len, Heap::kOld);
    symbol.SetHash(hash);  // Remember the calculated hash value.
    InsertIntoSymbolTable(symbol_table, symbol, index, table_size);
  }
  ASSERT(symbol.IsSymbol());
  return symbol.raw();
}

template RawString* String::NewSymbol(const uint8_t* characters, intptr_t len);
template RawString* String::NewSymbol(const uint16_t* characters, intptr_t len);
template RawString* String::NewSymbol(const uint32_t* characters, intptr_t len);


RawString* String::NewSymbol(const String& str) {
  if (str.IsSymbol()) {
    return str.raw();
  }
  return NewSymbol(str, 0, str.Length());
}


RawString* String::NewSymbol(const String& str,
                             intptr_t begin_index,
                             intptr_t len) {
  ASSERT(begin_index >= 0);
  ASSERT(len >= 0);
  ASSERT((begin_index + len) <= str.Length());
  Isolate* isolate = Isolate::Current();

  // Calculate the String hash for this sequence of characters.
  intptr_t hash = String::Hash(str, begin_index, len);

  const Array& symbol_table =
      Array::Handle(isolate, isolate->object_store()->symbol_table());
  // Last element of the array is the number of used elements.
  intptr_t table_size = symbol_table.Length() - 1;
  intptr_t index = hash % table_size;

  String& symbol = String::Handle(isolate, String::null());
  symbol ^= symbol_table.At(index);
  while (!symbol.IsNull() && !symbol.Equals(str, begin_index, len)) {
    index = (index + 1) % table_size;  // Move to next element.
    symbol ^= symbol_table.At(index);
  }
  // Since we leave enough room in the table to guarantee, that we find an
  // empty spot, index is the insertion point if symbol is null.
  if (symbol.IsNull()) {
    if (str.IsOld() && begin_index == 0 && len == str.Length()) {
      // Reuse the incoming str as the symbol value.
      symbol = str.raw();
    } else {
      // Allocate a copy in old space.
      symbol = String::SubString(str, begin_index, len, Heap::kOld);
    }
    symbol.SetHash(hash);
    InsertIntoSymbolTable(symbol_table, symbol, index, table_size);
  }
  ASSERT(symbol.IsSymbol());
  return symbol.raw();
}


RawString* String::NewFormatted(const char* format, ...) {
  va_list args;
  va_start(args, format);
  intptr_t len = OS::VSNPrint(NULL, 0, format, args);
  va_end(args);

  Zone* zone = Isolate::Current()->current_zone();
  char* buffer = reinterpret_cast<char*>(zone->Allocate(len + 1));
  va_list args2;
  va_start(args2, format);
  OS::VSNPrint(buffer, (len + 1), format, args2);
  va_end(args2);

  return String::New(buffer);
}


RawString* String::Concat(const String& str1,
                          const String& str2,
                          Heap::Space space) {
  ASSERT(!str1.IsNull() && !str2.IsNull());
  intptr_t char_size = Utils::Maximum(str1.CharSize(), str2.CharSize());
  if (char_size == kFourByteChar) {
    return FourByteString::Concat(str1, str2, space);
  }
  if (char_size == kTwoByteChar) {
    return TwoByteString::Concat(str1, str2, space);
  }
  return OneByteString::Concat(str1, str2, space);
}


RawString* String::ConcatAll(const Array& strings,
                             Heap::Space space) {
  ASSERT(!strings.IsNull());
  intptr_t result_len = 0;
  intptr_t strings_len = strings.Length();
  String& str = String::Handle();
  intptr_t char_size = kOneByteChar;
  for (intptr_t i = 0; i < strings_len; i++) {
    str ^= strings.At(i);
    result_len += str.Length();
    char_size = Utils::Maximum(char_size, str.CharSize());
  }
  if (char_size == kOneByteChar) {
    return OneByteString::ConcatAll(strings, result_len, space);
  } else if (char_size == kTwoByteChar) {
    return TwoByteString::ConcatAll(strings, result_len, space);
  }
  ASSERT(char_size == kFourByteChar);
  return FourByteString::ConcatAll(strings, result_len, space);
}


RawString* String::SubString(const String& str,
                             intptr_t begin_index,
                             Heap::Space space) {
  ASSERT(!str.IsNull());
  if (begin_index >= str.Length()) {
    return String::null();
  }
  return String::SubString(str, begin_index, (str.Length() - begin_index));
}


RawString* String::SubString(const String& str,
                             intptr_t begin_index,
                             intptr_t length,
                             Heap::Space space) {
  ASSERT(!str.IsNull());
  ASSERT(begin_index >= 0);
  ASSERT(length >= 0);
  if (begin_index >= str.Length()) {
    return String::null();
  }
  String& result = String::Handle();
  bool is_one_byte_string = true;
  bool is_two_byte_string = true;
  intptr_t char_size = str.CharSize();
  if (char_size == kTwoByteChar) {
    for (intptr_t i = begin_index; i < begin_index + length; ++i) {
      if (str.CharAt(i) > 0xFF) {
        is_one_byte_string = false;
        break;
      }
    }
  } else if (char_size == kFourByteChar) {
    for (intptr_t i = begin_index; i < begin_index + length; ++i) {
      if (str.CharAt(i) > 0xFFFF) {
        is_one_byte_string = false;
        is_two_byte_string = false;
        break;
      } else if (str.CharAt(i) > 0xFF) {
        is_one_byte_string = false;
      }
    }
  }
  if (is_one_byte_string) {
    result ^= OneByteString::New(length, space);
  } else if (is_two_byte_string) {
    result ^= TwoByteString::New(length, space);
  } else {
    result ^= FourByteString::New(length, space);
  }
  String::Copy(result, 0, str, begin_index, length);
  return result.raw();
}


const char* String::ToCString() const {
  intptr_t len = Utf8::Length(*this);
  Zone* zone = Isolate::Current()->current_zone();
  char* result = reinterpret_cast<char*>(zone->Allocate(len + 1));
  Utf8::Encode(*this, result, len);
  result[len] = 0;
  return result;
}


RawString* String::Transform(int32_t (*mapping)(int32_t ch),
                             const String& str,
                             Heap::Space space) {
  ASSERT(!str.IsNull());
  bool has_mapping = false;
  int32_t dst_max = 0;
  intptr_t len = str.Length();
  // TODO(cshapiro): assume a transform is required, rollback if not.
  for (intptr_t i = 0; i < len; ++i) {
    int32_t src = str.CharAt(i);
    int32_t dst = mapping(src);
    if (src != dst) {
      has_mapping = true;
    }
    dst_max = Utils::Maximum(dst_max, dst);
  }
  if (!has_mapping) {
    return str.raw();
  }
  if (dst_max <= 0xFF) {
    return OneByteString::Transform(mapping, str, space);
  }
  if (dst_max <= 0xFFFF) {
    return TwoByteString::Transform(mapping, str, space);
  }
  ASSERT(dst_max > 0xFFFF);
  return FourByteString::Transform(mapping, str, space);
}


RawString* String::ToUpperCase(const String& str, Heap::Space space) {
  // TODO(cshapiro): create a fast-path for OneByteString instances.
  return Transform(CaseMapping::ToUpper, str, space);
}


RawString* String::ToLowerCase(const String& str, Heap::Space space) {
  // TODO(cshapiro): create a fast-path for OneByteString instances.
  return Transform(CaseMapping::ToLower, str, space);
}


RawOneByteString* OneByteString::New(intptr_t len,
                                     Heap::Space space) {
  Isolate* isolate = Isolate::Current();

  const Class& cls =
      Class::Handle(isolate->object_store()->one_byte_string_class());
  OneByteString& result = OneByteString::Handle();
  {
    RawObject* raw = Object::Allocate(cls,
                                      OneByteString::InstanceSize(len),
                                      space);
    NoGCScope no_gc;
    result ^= raw;
    result.SetLength(len);
    result.SetHash(0);
  }
  return result.raw();
}


RawOneByteString* OneByteString::New(const uint8_t* characters,
                                     intptr_t len,
                                     Heap::Space space) {
  const OneByteString& result =
      OneByteString::Handle(OneByteString::New(len, space));
  String::Copy(result, 0, characters, len);
  return result.raw();
}


RawOneByteString* OneByteString::New(const uint16_t* characters,
                                     intptr_t len,
                                     Heap::Space space) {
  const OneByteString& result =
      OneByteString::Handle(OneByteString::New(len, space));
  String::Copy(result, 0, characters, len);
  return result.raw();
}


RawOneByteString* OneByteString::New(const uint32_t* characters,
                                     intptr_t len,
                                     Heap::Space space) {
  const OneByteString& result =
      OneByteString::Handle(OneByteString::New(len, space));
  String::Copy(result, 0, characters, len);
  return result.raw();
}


RawOneByteString* OneByteString::New(const OneByteString& str,
                                     Heap::Space space) {
  intptr_t len = str.Length();
  const OneByteString& result =
      OneByteString::Handle(OneByteString::New(len, space));
  String::Copy(result, 0, str, 0, len);
  return result.raw();
}


RawOneByteString* OneByteString::Concat(const String& str1,
                                        const String& str2,
                                        Heap::Space space) {
  intptr_t len1 = str1.Length();
  intptr_t len2 = str2.Length();
  intptr_t len = len1 + len2;
  const OneByteString& result =
      OneByteString::Handle(OneByteString::New(len, space));
  String::Copy(result, 0, str1, 0, len1);
  String::Copy(result, len1, str2, 0, len2);
  return result.raw();
}


RawOneByteString* OneByteString::ConcatAll(const Array& strings,
                                           intptr_t len,
                                           Heap::Space space) {
  const OneByteString& result =
      OneByteString::Handle(OneByteString::New(len, space));
  OneByteString& str = OneByteString::Handle();
  intptr_t strings_len = strings.Length();
  intptr_t pos = 0;
  for (intptr_t i = 0; i < strings_len; i++) {
    str ^= strings.At(i);
    intptr_t str_len = str.Length();
    String::Copy(result, pos, str, 0, str_len);
    pos += str_len;
  }
  return result.raw();
}


RawOneByteString* OneByteString::Transform(int32_t (*mapping)(int32_t ch),
                                           const String& str,
                                           Heap::Space space) {
  ASSERT(!str.IsNull());
  intptr_t len = str.Length();
  const OneByteString& result =
      OneByteString::Handle(OneByteString::New(len, space));
  for (intptr_t i = 0; i < len; ++i) {
    int32_t ch = mapping(str.CharAt(i));
    ASSERT(ch >= 0 && ch <= 0xFF);
    *result.CharAddr(i) = ch;
  }
  return result.raw();
}


const char* OneByteString::ToCString() const {
  return String::ToCString();
}


RawTwoByteString* TwoByteString::New(intptr_t len,
                                     Heap::Space space) {
  Isolate* isolate = Isolate::Current();

  const Class& cls =
      Class::Handle(isolate->object_store()->two_byte_string_class());
  TwoByteString& result = TwoByteString::Handle();
  {
    RawObject* raw = Object::Allocate(cls,
                                      TwoByteString::InstanceSize(len),
                                      space);
    NoGCScope no_gc;
    result ^= raw;
    result.SetLength(len);
    result.SetHash(0);
  }
  return result.raw();
}


RawTwoByteString* TwoByteString::New(const uint16_t* characters,
                                     intptr_t len,
                                     Heap::Space space) {
  const TwoByteString& result =
      TwoByteString::Handle(TwoByteString::New(len, space));
  String::Copy(result, 0, characters, len);
  return result.raw();
}


RawTwoByteString* TwoByteString::New(const uint32_t* characters,
                                     intptr_t len,
                                     Heap::Space space) {
  const TwoByteString& result =
      TwoByteString::Handle(TwoByteString::New(len, space));
  String::Copy(result, 0, characters, len);
  return result.raw();
}


RawTwoByteString* TwoByteString::New(const TwoByteString& str,
                                     Heap::Space space) {
  intptr_t len = str.Length();
  const TwoByteString& result =
      TwoByteString::Handle(TwoByteString::New(len, space));
  String::Copy(result, 0, str, 0, len);
  return result.raw();
}


RawTwoByteString* TwoByteString::Concat(const String& str1,
                                        const String& str2,
                                        Heap::Space space) {
  intptr_t len1 = str1.Length();
  intptr_t len2 = str2.Length();
  intptr_t len = len1 + len2;
  const TwoByteString& result =
      TwoByteString::Handle(TwoByteString::New(len, space));
  String::Copy(result, 0, str1, 0, len1);
  String::Copy(result, len1, str2, 0, len2);
  return result.raw();
}


RawTwoByteString* TwoByteString::ConcatAll(const Array& strings,
                                           intptr_t len,
                                           Heap::Space space) {
  const TwoByteString& result =
      TwoByteString::Handle(TwoByteString::New(len, space));
  String& str = String::Handle();
  intptr_t strings_len = strings.Length();
  intptr_t pos = 0;
  for (intptr_t i = 0; i < strings_len; i++) {
    str ^= strings.At(i);
    intptr_t str_len = str.Length();
    String::Copy(result, pos, str, 0, str_len);
    pos += str_len;
  }
  return result.raw();
}


RawTwoByteString* TwoByteString::Transform(int32_t (*mapping)(int32_t ch),
                                           const String& str,
                                           Heap::Space space) {
  ASSERT(!str.IsNull());
  intptr_t len = str.Length();
  const TwoByteString& result =
      TwoByteString::Handle(TwoByteString::New(len, space));
  for (intptr_t i = 0; i < len; ++i) {
    int32_t ch = mapping(str.CharAt(i));
    ASSERT(ch >= 0 && ch <= 0xFFFF);
    *result.CharAddr(i) = ch;
  }
  return result.raw();
}


const char* TwoByteString::ToCString() const {
  return String::ToCString();
}


RawFourByteString* FourByteString::New(intptr_t len,
                                       Heap::Space space) {
  Isolate* isolate = Isolate::Current();

  const Class& cls =
      Class::Handle(isolate->object_store()->four_byte_string_class());
  FourByteString& result = FourByteString::Handle();
  {
    RawObject* raw = Object::Allocate(cls,
                                      FourByteString::InstanceSize(len),
                                      space);
    NoGCScope no_gc;
    result ^= raw;
    result.SetLength(len);
    result.SetHash(0);
  }
  return result.raw();
}


RawFourByteString* FourByteString::New(const uint32_t* characters,
                                       intptr_t len,
                                       Heap::Space space) {
  const FourByteString& result =
      FourByteString::Handle(FourByteString::New(len, space));
  String::Copy(result, 0, characters, len);
  return result.raw();
}


RawFourByteString* FourByteString::New(const FourByteString& str,
                                       Heap::Space space) {
  return FourByteString::New(str.CharAddr(0), str.Length(), space);
}


RawFourByteString* FourByteString::Concat(const String& str1,
                                          const String& str2,
                                          Heap::Space space) {
  intptr_t len1 = str1.Length();
  intptr_t len2 = str2.Length();
  intptr_t len = len1 + len2;
  const FourByteString& result =
      FourByteString::Handle(FourByteString::New(len, space));
  String::Copy(result, 0, str1, 0, len1);
  String::Copy(result, len1, str2, 0, len2);
  return result.raw();
}


RawFourByteString* FourByteString::ConcatAll(const Array& strings,
                                             intptr_t len,
                                             Heap::Space space) {
  const FourByteString& result =
      FourByteString::Handle(FourByteString::New(len, space));
  String& str = String::Handle();
  {
    intptr_t strings_len = strings.Length();
    intptr_t pos = 0;
    for (intptr_t i = 0; i < strings_len; i++) {
      str ^= strings.At(i);
      intptr_t str_len = str.Length();
      String::Copy(result, pos, str, 0, str_len);
      pos += str_len;
    }
  }
  return result.raw();
}


RawFourByteString* FourByteString::Transform(int32_t (*mapping)(int32_t ch),
                                             const String& str,
                                             Heap::Space space) {
  ASSERT(!str.IsNull());
  intptr_t len = str.Length();
  const FourByteString& result =
      FourByteString::Handle(FourByteString::New(len, space));
  for (intptr_t i = 0; i < len; ++i) {
    int32_t ch = mapping(str.CharAt(i));
    ASSERT(ch >= 0 && ch <= 0x10FFFF);
    *result.CharAddr(i) = ch;
  }
  return result.raw();
}


const char* FourByteString::ToCString() const {
  return String::ToCString();
}


static void AddFinalizer(const Object& referent,
                         void* peer,
                         Dart_WeakPersistentHandleFinalizer callback) {
  ASSERT(callback != NULL);
  ApiState* state = Isolate::Current()->api_state();
  ASSERT(state != NULL);
  FinalizablePersistentHandle* weak_ref =
      state->weak_persistent_handles().AllocateHandle();
  weak_ref->set_raw(referent);
  weak_ref->set_peer(peer);
  weak_ref->set_callback(callback);
}


RawExternalOneByteString* ExternalOneByteString::New(
    const uint8_t* data,
    intptr_t len,
    void* peer,
    Dart_PeerFinalizer callback,
    Heap::Space space) {
  Isolate* isolate = Isolate::Current();

  const Class& cls =
      Class::Handle(isolate->object_store()->external_one_byte_string_class());
  ExternalOneByteString& result = ExternalOneByteString::Handle();
  ExternalStringData<uint8_t>* external_data =
      new ExternalStringData<uint8_t>(data, peer, callback);
  {
    RawObject* raw = Object::Allocate(cls,
                                      ExternalOneByteString::InstanceSize(),
                                      space);
    NoGCScope no_gc;
    result ^= raw;
    result.SetLength(len);
    result.SetHash(0);
    result.SetExternalData(external_data);
  }
  AddFinalizer(result, external_data, ExternalOneByteString::Finalize);
  return result.raw();
}


static void DeleteWeakPersistentHandle(Dart_Handle handle) {
  ApiState* state = Isolate::Current()->api_state();
  ASSERT(state != NULL);
  FinalizablePersistentHandle* weak_ref =
      reinterpret_cast<FinalizablePersistentHandle*>(handle);
  ASSERT(state->IsValidWeakPersistentHandle(handle));
  state->weak_persistent_handles().FreeHandle(weak_ref);
}


void ExternalOneByteString::Finalize(Dart_Handle handle, void* peer) {
  delete reinterpret_cast<ExternalStringData<uint8_t>*>(peer);
  DeleteWeakPersistentHandle(handle);
}


const char* ExternalOneByteString::ToCString() const {
  return String::ToCString();
}


RawExternalTwoByteString* ExternalTwoByteString::New(
    const uint16_t* data,
    intptr_t len,
    void* peer,
    Dart_PeerFinalizer callback,
    Heap::Space space) {
  Isolate* isolate = Isolate::Current();

  const Class& cls =
      Class::Handle(isolate->object_store()->external_two_byte_string_class());
  ExternalTwoByteString& result = ExternalTwoByteString::Handle();
  ExternalStringData<uint16_t>* external_data =
      new ExternalStringData<uint16_t>(data, peer, callback);
  {
    RawObject* raw = Object::Allocate(cls,
                                      ExternalTwoByteString::InstanceSize(),
                                      space);
    NoGCScope no_gc;
    result ^= raw;
    result.SetLength(len);
    result.SetHash(0);
    result.SetExternalData(external_data);
  }
  AddFinalizer(result, external_data, ExternalTwoByteString::Finalize);
  return result.raw();
}


void ExternalTwoByteString::Finalize(Dart_Handle handle, void* peer) {
  delete reinterpret_cast<ExternalStringData<uint16_t>*>(peer);
  DeleteWeakPersistentHandle(handle);
}


const char* ExternalTwoByteString::ToCString() const {
  return String::ToCString();
}


RawExternalFourByteString* ExternalFourByteString::New(
    const uint32_t* data,
    intptr_t len,
    void* peer,
    Dart_PeerFinalizer callback,
    Heap::Space space) {
  Isolate* isolate = Isolate::Current();

  const Class& cls =
      Class::Handle(isolate->object_store()->external_four_byte_string_class());
  ExternalFourByteString& result = ExternalFourByteString::Handle();
  ExternalStringData<uint32_t>* external_data =
      new ExternalStringData<uint32_t>(data, peer, callback);
  {
    RawObject* raw = Object::Allocate(cls,
                                      ExternalFourByteString::InstanceSize(),
                                      space);
    NoGCScope no_gc;
    result ^= raw;
    result.SetLength(len);
    result.SetHash(0);
    result.SetExternalData(external_data);
  }
  AddFinalizer(result, external_data, ExternalFourByteString::Finalize);
  return result.raw();
}


void ExternalFourByteString::Finalize(Dart_Handle handle, void* peer) {
  delete reinterpret_cast<ExternalStringData<uint32_t>*>(peer);
  DeleteWeakPersistentHandle(handle);
}


const char* ExternalFourByteString::ToCString() const {
  return String::ToCString();
}


RawBool* Bool::True() {
  return Isolate::Current()->object_store()->true_value();
}


RawBool* Bool::False() {
  return Isolate::Current()->object_store()->false_value();
}


RawBool* Bool::New(bool value) {
  Isolate* isolate = Isolate::Current();

  const Class& cls = Class::Handle(isolate->object_store()->bool_class());
  Bool& result = Bool::Handle();
  {
    // Since the two boolean instances are singletons we allocate them straight
    // in the old generation.
    RawObject* raw = Object::Allocate(cls, Bool::InstanceSize(), Heap::kOld);
    NoGCScope no_gc;
    result ^= raw;
  }
  result.set_value(value);
  return result.raw();
}


const char* Bool::ToCString() const {
  return value() ? "true" : "false";
}


bool Array::Equals(const Instance& other) const {
  if (this->raw() == other.raw()) {
    // Both handles point to the same raw instance.
    return true;
  }

  if (!other.IsArray() || other.IsNull()) {
    return false;
  }

  // Must have the same type arguments.
  if (!AbstractTypeArguments::AreEqual(
      AbstractTypeArguments::Handle(GetTypeArguments()),
      AbstractTypeArguments::Handle(other.GetTypeArguments()))) {
    return false;
  }

  Array& other_arr = Array::Handle();
  other_arr ^= other.raw();

  intptr_t len = this->Length();
  if (len != other_arr.Length()) {
    return false;
  }

  for (intptr_t i = 0; i < len; i++) {
    if (this->At(i) != other_arr.At(i)) {
      return false;
    }
  }
  return true;
}


RawArray* Array::New(intptr_t len, Heap::Space space) {
  ObjectStore* object_store = Isolate::Current()->object_store();
  Class& cls = Class::Handle(object_store->array_class());
  return New(cls, len, space);
}


RawArray* Array::New(const Class& cls, intptr_t len, Heap::Space space) {
  if ((len < 0) || (len > kMaxArrayElements)) {
    // TODO(srdjan): Verify that illegal argument is the right thing to throw.
    GrowableArray<const Object*> args;
    args.Add(&Smi::Handle(Smi::New(len)));
    Exceptions::ThrowByType(Exceptions::kIllegalArgument, args);
  }
  Array& result = Array::Handle();
  {
    RawObject* raw = Object::Allocate(cls,
                                      Array::InstanceSize(len),
                                      space);
    NoGCScope no_gc;
    result ^= raw;
    result.SetLength(len);
  }
  return result.raw();
}


void Array::MakeImmutable() const {
  Isolate* isolate = Isolate::Current();
  raw()->ptr()->class_ = isolate->object_store()->immutable_array_class();
}


const char* Array::ToCString() const {
  return "Array";
}


RawArray* Array::Grow(const Array& source, int new_length, Heap::Space space) {
  intptr_t len = source.IsNull() ? 0 : source.Length();
  ASSERT(new_length >= len);  // Cannot copy 'source' into new array.
  ASSERT(new_length != len);  // Unnecessary copying of array.
  const Array& result = Array::Handle(Array::New(new_length, space));
  Object& obj = Object::Handle();
  for (int i = 0; i < len; i++) {
    obj = source.At(i);
    result.SetAt(i, obj);
  }
  return result.raw();
}


RawArray* Array::Empty() {
  return Isolate::Current()->object_store()->empty_array();
}


RawArray* Array::MakeArray(const GrowableObjectArray& growable_array) {
  intptr_t used_len = growable_array.Length();
  intptr_t capacity_len = growable_array.Capacity();
  Isolate* isolate = Isolate::Current();
  Array& array = Array::Handle(isolate, growable_array.data());
  Array& new_array = Array::Handle(isolate, Array::Empty());
  intptr_t capacity_size = Array::InstanceSize(capacity_len);
  intptr_t used_size = Array::InstanceSize(used_len);
  NoGCScope no_gc;

  // Update the size in the header field and length of the array object.
  uword tags = 0;
  tags = RawObject::SizeTag::update(used_size, tags);
  array.raw_ptr()->tags_ = tags;
  array.SetLength(used_len);

  // Null the GrowableObjectArray, we are removing it's backing array.
  growable_array.SetLength(0);
  growable_array.SetData(new_array);

  // If there is any left over space fill it with either an Array object or
  // just a plain object (depending on the amount of left over space) so
  // that it can be traversed over successfully during garbage collection.
  if (capacity_size != used_size) {
    ASSERT(capacity_len > used_len);
    intptr_t leftover_size = capacity_size - used_size;

    uword addr = RawObject::ToAddr(array.raw()) + used_size;
    if (leftover_size >= Array::InstanceSize(0)) {
      // As we have enough space to use an array object, update the leftover
      // space as an Array object.
      RawArray* raw = reinterpret_cast<RawArray*>(RawObject::FromAddr(addr));
      raw->ptr()->class_ = isolate->object_store()->array_class();
      tags = 0;
      tags = RawObject::SizeTag::update(leftover_size, tags);
      raw->ptr()->tags_ = tags;
      intptr_t leftover_len =
          ((leftover_size - Array::InstanceSize(0)) / kWordSize);
      raw->ptr()->tags_ = tags;
      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));
      raw->ptr()->class_ = isolate->object_store()->object_class();
      tags = 0;
      tags = RawObject::SizeTag::update(leftover_size, tags);
      raw->ptr()->tags_ = tags;
    }
  }
  return array.raw();
}


RawImmutableArray* ImmutableArray::New(intptr_t len,
                                       Heap::Space space) {
  ObjectStore* object_store = Isolate::Current()->object_store();
  Class& cls = Class::Handle(object_store->immutable_array_class());
  return reinterpret_cast<RawImmutableArray*>(Array::New(cls, len, space));
}


const char* ImmutableArray::ToCString() const {
  return "ImmutableArray";
}


void GrowableObjectArray::Add(const Object& value, Heap::Space space) const {
  ASSERT(!IsNull());
  Array& contents = Array::Handle(data());
  if (Length() == Capacity()) {
    // TODO(Issue 2500): Need a better growth strategy.
    intptr_t new_capacity = (Capacity() == 0) ? 4 : Capacity() * 2;
    if (new_capacity <= Capacity()) {
      // Use the preallocated out of memory exception to avoid calling
      // into dart code or allocating any code.
      const Instance& exception =
          Instance::Handle(Isolate::Current()->object_store()->out_of_memory());
      Exceptions::Throw(exception);
      UNREACHABLE();
    }
    Grow(new_capacity, space);
    contents = data();
  }
  ASSERT(Length() < Capacity());
  intptr_t index = Length();
  SetLength(index + 1);
  contents.SetAt(index, value);
}


void GrowableObjectArray::Grow(intptr_t new_capacity, Heap::Space space) const {
  ASSERT(new_capacity > Capacity());
  const Array& contents = Array::Handle(data());
  const Array& new_contents =
      Array::Handle(Array::Grow(contents, new_capacity, space));
  StorePointer(&(raw_ptr()->data_), new_contents.raw());
}


RawObject* GrowableObjectArray::RemoveLast() const {
  ASSERT(!IsNull());
  ASSERT(Length() > 0);
  intptr_t index = Length() - 1;
  const Array& contents = Array::Handle(data());
  const Object& obj = Object::Handle(contents.At(index));
  contents.SetAt(index, Object::Handle());
  SetLength(index);
  return obj.raw();
}


bool GrowableObjectArray::Equals(const Instance& other) const {
  // If both handles point to the same raw instance they are equal.
  if (this->raw() == other.raw()) {
    return true;
  }

  // Other instance must be non null and a GrowableObjectArray.
  if (!other.IsGrowableObjectArray() || other.IsNull()) {
    return false;
  }

  GrowableObjectArray& other_arr = GrowableObjectArray::Handle();
  other_arr ^= other.raw();

  // The capacity and length of both objects must be equal.
  if (Capacity() != other_arr.Capacity() || Length() != other_arr.Length()) {
    return false;
  }

  // Both must have the same type arguments.
  if (!AbstractTypeArguments::AreEqual(
      AbstractTypeArguments::Handle(GetTypeArguments()),
      AbstractTypeArguments::Handle(other.GetTypeArguments()))) {
    return false;
  }

  // The data part in both arrays must be identical.
  const Array& contents = Array::Handle(data());
  const Array& other_contents = Array::Handle(other_arr.data());
  for (intptr_t i = 0; i < Length(); i++) {
    if (contents.At(i) != other_contents.At(i)) {
      return false;
    }
  }
  return true;
}


RawGrowableObjectArray* GrowableObjectArray::New(intptr_t capacity,
                                                 Heap::Space space) {
  const Array& data = Array::Handle(Array::New(capacity, space));
  return New(data, space);
}


RawGrowableObjectArray* GrowableObjectArray::New(const Array& array,
                                                 Heap::Space space) {
  ObjectStore* object_store = Isolate::Current()->object_store();
  Class& cls = Class::Handle(object_store->growable_object_array_class());
  GrowableObjectArray& result = GrowableObjectArray::Handle();
  {
    RawObject* raw = Object::Allocate(cls,
                                      GrowableObjectArray::InstanceSize(),
                                      space);
    NoGCScope no_gc;
    result ^= raw;
    result.SetLength(0);
    result.SetData(array);
  }
  return result.raw();
}


const char* GrowableObjectArray::ToCString() const {
  return "GrowableObjectArray";
}


intptr_t ByteArray::Length() const {
  // ByteArray is an abstract class.
  UNREACHABLE();
  return 0;
}


void ByteArray::Copy(uint8_t* dst,
                     const ByteArray& src,
                     intptr_t src_offset,
                     intptr_t length) {
  ASSERT(Utils::RangeCheck(src_offset, length, src.Length()));
  {
    NoGCScope no_gc;
    if (length > 0) {
      memmove(dst, src.ByteAddr(src_offset), length);
    }
  }
}


void ByteArray::Copy(const ByteArray& dst,
                     intptr_t dst_offset,
                     const uint8_t* src,
                     intptr_t length) {
  ASSERT(Utils::RangeCheck(dst_offset, length, dst.Length()));
  {
    NoGCScope no_gc;
    if (length > 0) {
      memmove(dst.ByteAddr(dst_offset), src, length);
    }
  }
}


void ByteArray::Copy(const ByteArray& dst,
                     intptr_t dst_offset,
                     const ByteArray& src,
                     intptr_t src_offset,
                     intptr_t length) {
  ASSERT(Utils::RangeCheck(src_offset, length, src.Length()));
  ASSERT(Utils::RangeCheck(dst_offset, length, dst.Length()));
  {
    NoGCScope no_gc;
    if (length > 0) {
      memmove(dst.ByteAddr(dst_offset), src.ByteAddr(src_offset), length);
    }
  }
}


uint8_t* ByteArray::ByteAddr(intptr_t byte_offset) const {
  // ByteArray is an abstract class.
  UNREACHABLE();
  return NULL;
}


const char* ByteArray::ToCString() const {
  // ByteArray is an abstract class.
  UNREACHABLE();
  return "ByteArray";
}


RawInternalByteArray* InternalByteArray::New(intptr_t len,
                                             Heap::Space space) {
  Isolate* isolate = Isolate::Current();
  const Class& internal_byte_array_class =
      Class::Handle(isolate->object_store()->internal_byte_array_class());
  InternalByteArray& result = InternalByteArray::Handle();
  {
    RawObject* raw = Object::Allocate(internal_byte_array_class,
                                      InternalByteArray::InstanceSize(len),
                                      space);
    NoGCScope no_gc;
    result ^= raw;
    result.SetLength(len);
    if (len > 0) {
      memset(result.Addr<uint8_t>(0), 0, len);
    }
  }
  return result.raw();
}


RawInternalByteArray* InternalByteArray::New(const uint8_t* data,
                                             intptr_t len,
                                             Heap::Space space) {
  InternalByteArray& result =
      InternalByteArray::Handle(InternalByteArray::New(len, space));
  {
    NoGCScope no_gc;
    if (len > 0) {
      memmove(result.Addr<uint8_t>(0), data, len);
    }
  }
  return result.raw();
}


const char* InternalByteArray::ToCString() const {
  return "_InternalByteArray";
}


void ExternalByteArray::Finalize(Dart_Handle handle, void* peer) {
  delete reinterpret_cast<ExternalByteArrayData*>(peer);
  DeleteWeakPersistentHandle(handle);
}


RawExternalByteArray* ExternalByteArray::New(uint8_t* data,
                                             intptr_t len,
                                             void* peer,
                                             Dart_PeerFinalizer callback,
                                             Heap::Space space) {
  Isolate* isolate = Isolate::Current();
  const Class& external_byte_array_class =
      Class::Handle(isolate->object_store()->external_byte_array_class());
  ExternalByteArray& result = ExternalByteArray::Handle();
  ExternalByteArrayData* external_data =
        new ExternalByteArrayData(data, peer, callback);
  {
    RawObject* raw = Object::Allocate(external_byte_array_class,
                                      ExternalByteArray::InstanceSize(),
                                      space);
    NoGCScope no_gc;
    result ^= raw;
    result.SetLength(len);
    result.SetExternalData(external_data);
  }
  AddFinalizer(result, external_data, ExternalByteArray::Finalize);
  return result.raw();
}


const char* ExternalByteArray::ToCString() const {
  return "_ExternalByteArray";
}


RawClosure* Closure::New(const Function& function,
                         const Context& context,
                         Heap::Space space) {
  Isolate* isolate = Isolate::Current();
  ASSERT(context.isolate() == isolate);

  const Class& cls = Class::Handle(function.signature_class());
  Closure& result = Closure::Handle();
  {
    RawObject* raw = Object::Allocate(cls, Closure::InstanceSize(), space);
    NoGCScope no_gc;
    result ^= raw;
  }
  result.set_function(function);
  result.set_context(context);
  return result.raw();
}


void Closure::set_context(const Context& value) const {
  raw_ptr()->context_ = value.raw();
}


void Closure::set_function(const Function& value) const {
  raw_ptr()->function_ = value.raw();
}


const char* Closure::ToCString() const {
  return "Closure";
}


intptr_t Stacktrace::Length() const {
  const Array& code_array = Array::Handle(raw_ptr()->code_array_);
  return code_array.Length();
}


RawFunction* Stacktrace::FunctionAtFrame(intptr_t frame_index) const {
  const Array& function_array = Array::Handle(raw_ptr()->function_array_);
  return reinterpret_cast<RawFunction*>(function_array.At(frame_index));
}


RawCode* Stacktrace::CodeAtFrame(intptr_t frame_index) const {
  const Array& code_array = Array::Handle(raw_ptr()->code_array_);
  return reinterpret_cast<RawCode*>(code_array.At(frame_index));
}


RawSmi* Stacktrace::PcOffsetAtFrame(intptr_t frame_index) const {
  const Array& pc_offset_array = Array::Handle(raw_ptr()->pc_offset_array_);
  return reinterpret_cast<RawSmi*>(pc_offset_array.At(frame_index));
}


void Stacktrace::set_function_array(const Array& function_array) const {
  StorePointer(&raw_ptr()->function_array_, function_array.raw());
}


void Stacktrace::set_code_array(const Array& code_array) const {
  StorePointer(&raw_ptr()->code_array_, code_array.raw());
}


void Stacktrace::set_pc_offset_array(const Array& pc_offset_array) const {
  StorePointer(&raw_ptr()->pc_offset_array_, pc_offset_array.raw());
}


void Stacktrace::SetupStacktrace(intptr_t index,
                                 const GrowableArray<uword>& frame_pcs) const {
  Isolate* isolate = Isolate::Current();
  ASSERT(isolate != NULL);
  Function& function = Function::Handle(isolate, Function::null());
  Code& code = Code::Handle(isolate, Code::null());
  Smi& pc_offset = Smi::Handle(isolate, Smi::New(0));
  const Array& function_array = Array::Handle(raw_ptr()->function_array_);
  const Array& code_array = Array::Handle(raw_ptr()->code_array_);
  const Array& pc_offset_array = Array::Handle(raw_ptr()->pc_offset_array_);
  for (intptr_t i = 0; i < frame_pcs.length(); i++) {
    code = StackFrame::LookupCode(isolate, frame_pcs[i]);
    ASSERT(!code.IsNull());
    function = code.function();
    function_array.SetAt((index + i), function);
    code_array.SetAt((index + i), code);
    pc_offset = Smi::New(frame_pcs[i] - code.EntryPoint());
    pc_offset_array.SetAt((index + i), pc_offset);
  }
}


RawStacktrace* Stacktrace::New(const GrowableArray<uword>& stack_frame_pcs,
                               Heap::Space space) {
  const Class& cls = Class::Handle(
      Isolate::Current()->object_store()->stacktrace_class());
  Stacktrace& result = Stacktrace::Handle();
  {
    RawObject* raw = Object::Allocate(cls,
                                      Stacktrace::InstanceSize(),
                                      space);
    NoGCScope no_gc;
    result ^= raw;
  }
  intptr_t length = stack_frame_pcs.length();
  // Create arrays for the function, code and pc_offset triplet for each frame.
  const Array& function_array = Array::Handle(Array::New(length));
  const Array& code_array = Array::Handle(Array::New(length));
  const Array& pc_offset_array = Array::Handle(Array::New(length));
  result.set_function_array(function_array);
  result.set_code_array(code_array);
  result.set_pc_offset_array(pc_offset_array);
  // Now populate the arrays with appropriate values from each frame.
  result.SetupStacktrace(0, stack_frame_pcs);
  return result.raw();
}


void Stacktrace::Append(const GrowableArray<uword>& stack_frame_pcs) const {
  intptr_t old_length = Length();
  intptr_t new_length = old_length + stack_frame_pcs.length();

  // Grow the arrays for function, code and pc_offset triplet to accommodate
  // the new stack frames.
  Array& function_array = Array::Handle(raw_ptr()->function_array_);
  Array& code_array = Array::Handle(raw_ptr()->code_array_);
  Array& pc_offset_array = Array::Handle(raw_ptr()->pc_offset_array_);
  function_array = Array::Grow(function_array, new_length);
  code_array = Array::Grow(code_array, new_length);
  pc_offset_array = Array::Grow(pc_offset_array, new_length);
  set_function_array(function_array);
  set_code_array(code_array);
  set_pc_offset_array(pc_offset_array);
  // Now populate the arrays with appropriate values from each new frame.
  SetupStacktrace(old_length, stack_frame_pcs);
}


const char* Stacktrace::ToCStringInternal(bool verbose) const {
  Function& function = Function::Handle();
  Code& code = Code::Handle();
  Class& function_class = Class::Handle();
  Script& script = Script::Handle();
  String& function_name = String::Handle();
  String& class_name = String::Handle();
  String& url = String::Handle();

  // Iterate through the stack frames and create C string description
  // for each frame.
  intptr_t total_len = 0;
  const char* kFormat = verbose ?
      " %d. Function: '%s%s%s' url: '%s' line:%d col:%d code-entry: 0x%x\n" :
      " %d. Function: '%s%s%s' url: '%s' line:%d col:%d\n";
  GrowableArray<char*> frame_strings;
  for (intptr_t i = 0; i < Length(); i++) {
    function = FunctionAtFrame(i);
    code = CodeAtFrame(i);
    uword pc = code.EntryPoint() + Smi::Value(PcOffsetAtFrame(i));
    intptr_t token_index = code.GetTokenIndexOfPC(pc);
    function_class = function.owner();
    script = function_class.script();
    function_name = function.name();
    class_name = function_class.Name();
    url = script.url();
    intptr_t line = -1;
    intptr_t column = -1;
    if (token_index >= 0) {
      script.GetTokenLocation(token_index, &line, &column);
    }
    intptr_t len = OS::SNPrint(NULL, 0, kFormat,
                               i,
                               class_name.ToCString(),
                               function_class.IsTopLevel() ? "" : ".",
                               function_name.ToCString(),
                               url.ToCString(),
                               line, column,
                               code.EntryPoint());
    total_len += len;
    char* chars = reinterpret_cast<char*>(
        Isolate::Current()->current_zone()->Allocate(len + 1));
    OS::SNPrint(chars, (len + 1), kFormat,
                i,
                class_name.ToCString(),
                function_class.IsTopLevel() ? "" : ".",
                function_name.ToCString(),
                url.ToCString(),
                line, column,
                code.EntryPoint());
    frame_strings.Add(chars);
  }

  // Now concatentate the frame descriptions into a single C string.
  char* chars = reinterpret_cast<char*>(
      Isolate::Current()->current_zone()->Allocate(total_len + 1));
  intptr_t index = 0;
  for (intptr_t i = 0; i < frame_strings.length(); i++) {
    index += OS::SNPrint((chars + index),
                         (total_len + 1 - index),
                         "%s",
                         frame_strings[i]);
  }
  return chars;
}


const char* Stacktrace::ToCString() const {
  return ToCStringInternal(false);
}


void JSRegExp::set_pattern(const String& pattern) const {
  StorePointer(&raw_ptr()->pattern_, pattern.raw());
}


void JSRegExp::set_num_bracket_expressions(intptr_t value) const {
  raw_ptr()->num_bracket_expressions_ = Smi::New(value);
}


RawJSRegExp* JSRegExp::New(intptr_t len, Heap::Space space) {
  const Class& cls = Class::Handle(
      Isolate::Current()->object_store()->jsregexp_class());
  JSRegExp& result = JSRegExp::Handle();
  {
    RawObject* raw = Object::Allocate(cls,
                                      JSRegExp::InstanceSize(len),
                                      space);
    NoGCScope no_gc;
    result ^= raw;
    result.set_type(kUnitialized);
    result.set_flags(0);
    result.SetLength(len);
  }
  return result.raw();
}


void* JSRegExp::GetDataStartAddress() const {
  intptr_t addr = reinterpret_cast<intptr_t>(raw_ptr());
  return reinterpret_cast<void*>(addr + sizeof(RawJSRegExp));
}


RawJSRegExp* JSRegExp::FromDataStartAddress(void* data) {
  JSRegExp& regexp = JSRegExp::Handle();
  intptr_t addr = reinterpret_cast<intptr_t>(data) - sizeof(RawJSRegExp);
  regexp ^= RawObject::FromAddr(addr);
  return regexp.raw();
}


const char* JSRegExp::Flags() const {
  switch (raw_ptr()->flags_) {
    case kGlobal | kIgnoreCase | kMultiLine :
    case kIgnoreCase | kMultiLine :
      return "im";
    case kGlobal | kIgnoreCase :
    case kIgnoreCase:
      return "i";
    case kGlobal | kMultiLine :
    case kMultiLine:
      return "m";
    default:
      break;
  }
  return "";
}


bool JSRegExp::Equals(const Instance& other) const {
  if (this->raw() == other.raw()) {
    return true;  // "===".
  }
  if (other.IsNull() || !other.IsJSRegExp()) {
    return false;
  }
  JSRegExp& other_js = JSRegExp::Handle();
  other_js ^= other.raw();
  // Match the pattern.
  const String& str1 = String::Handle(pattern());
  const String& str2 = String::Handle(other_js.pattern());
  if (!str1.Equals(str2)) {
    return false;
  }
  // Match the flags.
  if ((is_global() != other_js.is_global()) ||
      (is_ignore_case() != other_js.is_ignore_case()) ||
      (is_multi_line() != other_js.is_multi_line())) {
    return false;
  }
  return true;
}


const char* JSRegExp::ToCString() const {
  const String& str = String::Handle(pattern());
  const char* format = "JSRegExp: pattern=%s flags=%s";
  intptr_t len = OS::SNPrint(NULL, 0, format, str.ToCString(), Flags());
  char* chars = reinterpret_cast<char*>(
      Isolate::Current()->current_zone()->Allocate(len + 1));
  OS::SNPrint(chars, (len + 1), format, str.ToCString(), Flags());
  return chars;
}

}  // namespace dart