Remove isolate argument from handle allocation: Part II

runtime/vm/object.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/object.h"
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "vm/assembler.h"
 #include "vm/cpu.h"
@@ skipping 894 matching lines @@
   *extractor_parameter_names_ = Array::New(1, Heap::kOld);
   extractor_parameter_names_->SetAt(0, Symbols::This());
 
   ASSERT(!extractor_parameter_types_->IsSmi());
   ASSERT(extractor_parameter_types_->IsArray());
   ASSERT(!extractor_parameter_names_->IsSmi());
   ASSERT(extractor_parameter_names_->IsArray());
 
 
   // Set up names for all VM singleton classes.
-  Class& cls = Class::Handle(isolate);
+  Class& cls = Class::Handle();
 
   SET_CLASS_NAME(class, Class);
   SET_CLASS_NAME(dynamic, Dynamic);
   SET_CLASS_NAME(void, Void);
   SET_CLASS_NAME(unresolved_class, UnresolvedClass);
   SET_CLASS_NAME(type_arguments, TypeArguments);
   SET_CLASS_NAME(patch_class, PatchClass);
   SET_CLASS_NAME(function, Function);
   SET_CLASS_NAME(closure_data, ClosureData);
   SET_CLASS_NAME(redirection_data, RedirectionData);
@@ skipping 90 matching lines @@
         tags = AtomicOperations::CompareAndSwapWord(
             &raw->ptr()->tags_, old_tags, new_tags);
       } while (tags != old_tags);
     }
   }
 }
 
 
 void Object::VerifyBuiltinVtables() {
 #if defined(DEBUG)
-  Isolate* isolate = Isolate::Current();
-  ASSERT(isolate != NULL);
-  Class& cls = Class::Handle(isolate, Class::null());
+  Thread* thread = Thread::Current();
+  Isolate* isolate = thread->isolate();
+  Class& cls = Class::Handle(thread->zone(), Class::null());
   for (intptr_t cid = (kIllegalCid + 1); cid < kNumPredefinedCids; cid++) {
     if (isolate->class_table()->HasValidClassAt(cid)) {
       cls ^= isolate->class_table()->At(cid);
       ASSERT(builtin_vtables_[cid] == cls.raw_ptr()->handle_vtable_);
     }
   }
   ASSERT(builtin_vtables_[kFreeListElement] == 0);
 #endif
 }
 
@@ skipping 15 matching lines @@
   ASSERT(public_class_name.CharAt(0) == '_');
   String& str = String::Handle();
   str = lib.PrivateName(public_class_name);
   cls.set_name(str);
   lib.AddClass(cls);
 }
 
 
 RawError* Object::Init(Isolate* isolate) {
   Thread* thread = Thread::Current();
+  Zone* zone = thread->zone();
   ASSERT(isolate == thread->isolate());
   TimelineDurationScope tds(thread,
                             isolate->GetIsolateStream(),
                             "Object::Init");
 
 #if defined(DART_NO_SNAPSHOT)
   // Object::Init version when we are running in a version of dart that does
   // not have a full snapshot linked in.
   ObjectStore* object_store = isolate->object_store();
 
-  Class& cls = Class::Handle(isolate);
-  Type& type = Type::Handle(isolate);
-  Array& array = Array::Handle(isolate);
-  Library& lib = Library::Handle(isolate);
+  Class& cls = Class::Handle(zone);
+  Type& type = Type::Handle(zone);
+  Array& array = Array::Handle(zone);
+  Library& lib = Library::Handle(zone);
 
   // 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);
 
   // VM classes that are parameterized (Array, ImmutableArray,
   // GrowableObjectArray, and LinkedHashMap) are also pre-finalized,
   // so CalculateFieldOffsets() is not called, so we need to set the
   // offset of their type_arguments_ field, which is explicitly
   // declared in their respective Raw* classes.
   cls.set_type_arguments_field_offset(Array::type_arguments_offset());
   cls.set_num_type_arguments(1);
 
   // Set up the growable object array class (Has to be done after the array
   // class is setup as one of its field is an array object).
   cls = Class::New<GrowableObjectArray>();
   object_store->set_growable_object_array_class(cls);
   cls.set_type_arguments_field_offset(
       GrowableObjectArray::type_arguments_offset());
   cls.set_num_type_arguments(1);
 
   // canonical_type_arguments_ are Smi terminated.
   // Last element contains the count of used slots.
   const intptr_t kInitialCanonicalTypeArgumentsSize = 4;
   array = Array::New(kInitialCanonicalTypeArgumentsSize + 1);
   array.SetAt(kInitialCanonicalTypeArgumentsSize,
-              Smi::Handle(isolate, Smi::New(0)));
+              Smi::Handle(zone, Smi::New(0)));
   object_store->set_canonical_type_arguments(array);
 
   // Setup type class early in the process.
-  const Class& type_cls = Class::Handle(isolate, Class::New<Type>());
-  const Class& type_ref_cls = Class::Handle(isolate, Class::New<TypeRef>());
-  const Class& type_parameter_cls = Class::Handle(isolate,
+  const Class& type_cls = Class::Handle(zone, Class::New<Type>());
+  const Class& type_ref_cls = Class::Handle(zone, Class::New<TypeRef>());
+  const Class& type_parameter_cls = Class::Handle(zone,
                                                   Class::New<TypeParameter>());
-  const Class& bounded_type_cls = Class::Handle(isolate,
+  const Class& bounded_type_cls = Class::Handle(zone,
                                                 Class::New<BoundedType>());
-  const Class& mixin_app_type_cls = Class::Handle(isolate,
+  const Class& mixin_app_type_cls = Class::Handle(zone,
                                                   Class::New<MixinAppType>());
-  const Class& library_prefix_cls = Class::Handle(isolate,
+  const Class& library_prefix_cls = Class::Handle(zone,
                                                   Class::New<LibraryPrefix>());
 
   // Pre-allocate the OneByteString class needed by the symbol table.
   cls = Class::NewStringClass(kOneByteStringCid);
   object_store->set_one_byte_string_class(cls);
 
   // Pre-allocate the TwoByteString class needed by the symbol table.
   cls = Class::NewStringClass(kTwoByteStringCid);
   object_store->set_two_byte_string_class(cls);
 
   // Setup the symbol table for the symbols created in the isolate.
   Symbols::SetupSymbolTable(isolate);
 
   // Set up the libraries array before initializing the core library.
   const GrowableObjectArray& libraries = GrowableObjectArray::Handle(
-      isolate, GrowableObjectArray::New(Heap::kOld));
+      zone, GrowableObjectArray::New(Heap::kOld));
   object_store->set_libraries(libraries);
 
   // Pre-register the core library.
   Library::InitCoreLibrary(isolate);
 
   // Basic infrastructure has been setup, initialize the class dictionary.
-  const Library& core_lib = Library::Handle(isolate, Library::CoreLibrary());
+  const Library& core_lib = Library::Handle(zone, Library::CoreLibrary());
   ASSERT(!core_lib.IsNull());
 
   const GrowableObjectArray& pending_classes =
-      GrowableObjectArray::Handle(isolate, GrowableObjectArray::New());
+      GrowableObjectArray::Handle(zone, GrowableObjectArray::New());
   object_store->set_pending_classes(pending_classes);
 
-  Context& context = Context::Handle(isolate, Context::New(0, Heap::kOld));
+  Context& context = Context::Handle(zone, Context::New(0, Heap::kOld));
   object_store->set_empty_context(context);
 
   // Now that the symbol table is initialized and that the core dictionary as
   // well as the core implementation dictionary have been setup, preallocate
   // remaining classes and register them by name in the dictionaries.
-  String& name = String::Handle(isolate);
+  String& name = String::Handle(zone);
   cls = object_store->array_class();  // Was allocated above.
   RegisterPrivateClass(cls, Symbols::_List(), core_lib);
   pending_classes.Add(cls);
   // We cannot use NewNonParameterizedType(cls), because Array is parameterized.
   // Warning: class _List has not been patched yet. Its declared number of type
   // parameters is still 0. It will become 1 after patching. The array type
   // allocated below represents the raw type _List and not _List<E> as we
   // could expect. Use with caution.
-  type ^= Type::New(Object::Handle(isolate, cls.raw()),
-                    TypeArguments::Handle(isolate),
+  type ^= Type::New(Object::Handle(zone, cls.raw()),
+                    TypeArguments::Handle(zone),
                     Scanner::kNoSourcePos);
   type.SetIsFinalized();
   type ^= type.Canonicalize();
   object_store->set_array_type(type);
 
   cls = object_store->growable_object_array_class();  // Was allocated above.
   RegisterPrivateClass(cls, Symbols::_GrowableList(), core_lib);
   pending_classes.Add(cls);
 
   cls = Class::New<Array>(kImmutableArrayCid);
@@ skipping 19 matching lines @@
   pending_classes.Add(cls);
 
   cls = Class::NewStringClass(kExternalTwoByteStringCid);
   object_store->set_external_two_byte_string_class(cls);
   RegisterPrivateClass(cls, Symbols::ExternalTwoByteString(), core_lib);
   pending_classes.Add(cls);
 
   // Pre-register the isolate library so the native class implementations
   // can be hooked up before compiling it.
   Library& isolate_lib =
-      Library::Handle(isolate, Library::LookupLibrary(Symbols::DartIsolate()));
+      Library::Handle(zone, Library::LookupLibrary(Symbols::DartIsolate()));
   if (isolate_lib.IsNull()) {
     isolate_lib = Library::NewLibraryHelper(Symbols::DartIsolate(), true);
     isolate_lib.SetLoadRequested();
     isolate_lib.Register();
     object_store->set_bootstrap_library(ObjectStore::kIsolate, isolate_lib);
   }
   ASSERT(!isolate_lib.IsNull());
   ASSERT(isolate_lib.raw() == Library::IsolateLibrary());
 
   cls = Class::New<Capability>();
   RegisterPrivateClass(cls, Symbols::_CapabilityImpl(), isolate_lib);
   pending_classes.Add(cls);
 
   cls = Class::New<ReceivePort>();
   RegisterPrivateClass(cls, Symbols::_RawReceivePortImpl(), isolate_lib);
   pending_classes.Add(cls);
 
   cls = Class::New<SendPort>();
   RegisterPrivateClass(cls, Symbols::_SendPortImpl(), isolate_lib);
   pending_classes.Add(cls);
 
-  const Class& stacktrace_cls = Class::Handle(isolate,
+  const Class& stacktrace_cls = Class::Handle(zone,
                                               Class::New<Stacktrace>());
   RegisterPrivateClass(stacktrace_cls, Symbols::_StackTrace(), core_lib);
   pending_classes.Add(stacktrace_cls);
   // Super type set below, after Object is allocated.
 
   cls = Class::New<JSRegExp>();
   RegisterPrivateClass(cls, Symbols::JSSyntaxRegExp(), core_lib);
   pending_classes.Add(cls);
 
   // Initialize the base interfaces used by the core VM classes.
@@ skipping 306 matching lines @@
   Intrinsifier::InitializeState();
 
   // Set up recognized state of all functions (core, math and typed data).
   MethodRecognizer::InitializeState();
 
   // Adds static const fields (class ids) to the class 'ClassID');
   lib = Library::LookupLibrary(Symbols::DartInternal());
   ASSERT(!lib.IsNull());
   cls = lib.LookupClassAllowPrivate(Symbols::ClassID());
   ASSERT(!cls.IsNull());
-  Field& field = Field::Handle(isolate);
-  Smi& value = Smi::Handle(isolate);
-  String& field_name = String::Handle(isolate);
+  Field& field = Field::Handle(zone);
+  Smi& value = Smi::Handle(zone);
+  String& field_name = String::Handle(zone);
 
 #define CLASS_LIST_WITH_NULL(V)                                                \
   V(Null)                                                                      \
   CLASS_LIST_NO_OBJECT(V)
 
 #define ADD_SET_FIELD(clazz)                                                   \
   field_name = Symbols::New("cid"#clazz);                                      \
   field = Field::New(field_name, true, false, true, false, cls, 0);            \
   value = Smi::New(k##clazz##Cid);                                             \
   field.SetStaticValue(value, true);                                           \
@@ skipping 107 matching lines @@
   cls = Class::New<Stacktrace>();
   cls = Class::New<JSRegExp>();
   cls = Class::New<Number>();
 
   cls = Class::New<WeakProperty>();
   object_store->set_weak_property_class(cls);
 
   cls = Class::New<MirrorReference>();
   cls = Class::New<UserTag>();
 
-  const Context& context = Context::Handle(isolate,
+  const Context& context = Context::Handle(zone,
                                            Context::New(0, Heap::kOld));
   object_store->set_empty_context(context);
 
 #endif  // defined(DART_NO_SNAPSHOT).
 
   return Error::null();
 }
 
 
 void Object::Print() const {
@@ skipping 753 matching lines @@
   type_params = type_parameters();
   return type_params.Length();
 }
 
 
 intptr_t Class::NumOwnTypeArguments() const {
   // Return cached value if already calculated.
   if (num_own_type_arguments() != kUnknownNumTypeArguments) {
     return num_own_type_arguments();
   }
-  Isolate* isolate = Isolate::Current();
+  Thread* thread = Thread::Current();
+  Isolate* isolate = thread->isolate();
+  Zone* zone = thread->zone();
   const intptr_t num_type_params = NumTypeParameters();
   if (!FLAG_overlap_type_arguments ||
       (num_type_params == 0) ||
       (super_type() == AbstractType::null()) ||
       (super_type() == isolate->object_store()->object_type())) {
     set_num_own_type_arguments(num_type_params);
     return num_type_params;
   }
   ASSERT(!IsMixinApplication() || is_mixin_type_applied());
-  const AbstractType& sup_type = AbstractType::Handle(isolate, super_type());
+  const AbstractType& sup_type = AbstractType::Handle(zone, super_type());
   const TypeArguments& sup_type_args =
-      TypeArguments::Handle(isolate, sup_type.arguments());
+      TypeArguments::Handle(zone, sup_type.arguments());
   if (sup_type_args.IsNull()) {
     // The super type is raw or the super class is non generic.
     // In either case, overlapping is not possible.
     set_num_own_type_arguments(num_type_params);
     return num_type_params;
   }
   const intptr_t num_sup_type_args = sup_type_args.Length();
   // At this point, the super type may or may not be finalized. In either case,
   // the result of this function must remain the same.
   // The value of num_sup_type_args may increase when the super type is
   // finalized, but the last num_sup_type_args type arguments will not be
   // modified by finalization, only shifted to higher indices in the vector.
   // They may however get wrapped in a BoundedType, which we skip.
   // The super type may not even be resolved yet. This is not necessary, since
   // we only check for matching type parameters, which are resolved by default.
   const TypeArguments& type_params =
-      TypeArguments::Handle(isolate, type_parameters());
+      TypeArguments::Handle(zone, type_parameters());
   // Determine the maximum overlap of a prefix of the vector consisting of the
   // type parameters of this class with a suffix of the vector consisting of the
   // type arguments of the super type of this class.
   // The number of own type arguments of this class is the number of its type
   // parameters minus the number of type arguments in the overlap.
   // Attempt to overlap the whole vector of type parameters; reduce the size
   // of the vector (keeping the first type parameter) until it fits or until
   // its size is zero.
-  TypeParameter& type_param = TypeParameter::Handle(isolate);
-  AbstractType& sup_type_arg = AbstractType::Handle(isolate);
+  TypeParameter& type_param = TypeParameter::Handle(zone);
+  AbstractType& sup_type_arg = AbstractType::Handle(zone);
   for (intptr_t num_overlapping_type_args =
            (num_type_params < num_sup_type_args) ?
                num_type_params : num_sup_type_args;
        num_overlapping_type_args > 0; num_overlapping_type_args--) {
     intptr_t i = 0;
     for (; i < num_overlapping_type_args; i++) {
       type_param ^= type_params.TypeAt(i);
       sup_type_arg = sup_type_args.TypeAt(
           num_sup_type_args - num_overlapping_type_args + i);
       // BoundedType can nest in case the finalized super type has bounded type
@@ skipping 21 matching lines @@
 
 
 intptr_t Class::NumTypeArguments() const {
   // Return cached value if already calculated.
   if (num_type_arguments() != kUnknownNumTypeArguments) {
     return num_type_arguments();
   }
   // To work properly, this call requires the super class of this class to be
   // resolved, which is checked by the type_class() call on the super type.
   // Note that calling type_class() on a MixinAppType fails.
-  Isolate* isolate = Isolate::Current();
-  Class& cls = Class::Handle(isolate);
-  AbstractType& sup_type = AbstractType::Handle(isolate);
+  Thread* thread = Thread::Current();
+  Zone* zone = thread->zone();
+  Isolate* isolate = thread->isolate();
+  Class& cls = Class::Handle(zone);
+  AbstractType& sup_type = AbstractType::Handle(zone);
   cls = raw();
   intptr_t num_type_args = 0;
   do {
     if (cls.IsSignatureClass()) {
-      Function& signature_fun = Function::Handle(isolate);
+      Function& signature_fun = Function::Handle(zone);
       signature_fun ^= cls.signature_function();
       if (!signature_fun.is_static() &&
           !signature_fun.HasInstantiatedSignature()) {
         cls = signature_fun.Owner();
       }
     }
     // Calling NumOwnTypeArguments() on a mixin application class will setup the
     // type parameters if not already done.
     num_type_args += cls.NumOwnTypeArguments();
     // Super type of Object class is null.
@@ skipping 1241 matching lines @@
 // be resolved as well as their interfaces.
 bool Class::TypeTestNonRecursive(const Class& cls,
                                  Class::TypeTestKind test_kind,
                                  const TypeArguments& type_arguments,
                                  const Class& other,
                                  const TypeArguments& other_type_arguments,
                                  Error* bound_error,
                                  Heap::Space space) {
   // Use the thsi object as if it was the receiver of this method, but instead
   // of recursing reset it to the super class and loop.
-  Isolate* isolate = Isolate::Current();
-  Class& thsi = Class::Handle(isolate, cls.raw());
+  Zone* zone = Thread::Current()->zone();
+  Class& thsi = Class::Handle(zone, cls.raw());
   while (true) {
     ASSERT(!thsi.IsVoidClass());
     // Check for DynamicType.
     // Each occurrence of DynamicType in type T is interpreted as the dynamic
     // type, a supertype of all types.
     if (other.IsDynamicClass()) {
       return true;
     }
     // In the case of a subtype test, each occurrence of DynamicType in type S
     // is interpreted as the bottom type, a subtype of all types.
@@ skipping 37 matching lines @@
       }
       return type_arguments.TypeTest(test_kind,
                                      other_type_arguments,
                                      from_index,
                                      num_type_params,
                                      bound_error,
                                      space);
     }
     const bool other_is_function_class = other.IsFunctionClass();
     if (other.IsSignatureClass() || other_is_function_class) {
-      const Function& other_fun = Function::Handle(isolate,
+      const Function& other_fun = Function::Handle(zone,
                                                    other.signature_function());
       if (thsi.IsSignatureClass()) {
         if (other_is_function_class) {
           return true;
         }
         // Check for two function types.
         const Function& fun =
-            Function::Handle(isolate, thsi.signature_function());
+            Function::Handle(zone, thsi.signature_function());
         return fun.TypeTest(test_kind,
                             type_arguments,
                             other_fun,
                             other_type_arguments,
                             bound_error,
                             space);
       }
       // Check if type S has a call() method of function type T.
       Function& function =
-          Function::Handle(isolate,
-                           thsi.LookupDynamicFunction(Symbols::Call()));
+          Function::Handle(zone, thsi.LookupDynamicFunction(Symbols::Call()));
       if (function.IsNull()) {
         // Walk up the super_class chain.
-        Class& cls = Class::Handle(isolate, thsi.SuperClass());
+        Class& cls = Class::Handle(zone, thsi.SuperClass());
         while (!cls.IsNull() && function.IsNull()) {
           function = cls.LookupDynamicFunction(Symbols::Call());
           cls = cls.SuperClass();
         }
       }
       if (!function.IsNull()) {
         if (other_is_function_class ||
             function.TypeTest(test_kind,
                               type_arguments,
                               other_fun,
                               other_type_arguments,
                               bound_error,
                               space)) {
               return true;
             }
       }
     }
     // Check for 'direct super type' specified in the implements clause
     // and check for transitivity at the same time.
-    Array& interfaces = Array::Handle(isolate, thsi.interfaces());
-    AbstractType& interface = AbstractType::Handle(isolate);
-    Class& interface_class = Class::Handle(isolate);
-    TypeArguments& interface_args = TypeArguments::Handle(isolate);
-    Error& error = Error::Handle(isolate);
+    Array& interfaces = Array::Handle(zone, thsi.interfaces());
+    AbstractType& interface = AbstractType::Handle(zone);
+    Class& interface_class = Class::Handle(zone);
+    TypeArguments& interface_args = TypeArguments::Handle(zone);
+    Error& error = Error::Handle(zone);
     for (intptr_t i = 0; i < interfaces.Length(); i++) {
       interface ^= interfaces.At(i);
       if (!interface.IsFinalized()) {
         // We may be checking bounds at finalization time and can encounter
         // a still unfinalized interface.
         ClassFinalizer::FinalizeType(
             thsi, interface, ClassFinalizer::kCanonicalize);
         interfaces.SetAt(i, interface);
       }
       if (interface.IsMalbounded()) {
@@ skipping 287 matching lines @@
 
   // No function found.
   return Function::null();
 }
 
 
 RawFunction* Class::LookupFunctionAtToken(intptr_t token_pos) const {
   // TODO(hausner): we can shortcut the negative case if we knew the
   // beginning and end token position of the class.
   Thread* thread = Thread::Current();
-  Isolate* isolate = thread->isolate();
+  Zone* zone = thread->zone();
   if (EnsureIsFinalized(thread) != Error::null()) {
     return Function::null();
   }
-  Function& func = Function::Handle(isolate);
+  Function& func = Function::Handle(zone);
   func = LookupClosureFunction(token_pos);
   if (!func.IsNull()) {
     return func.raw();
   }
-  Array& funcs = Array::Handle(isolate, functions());
+  Array& funcs = Array::Handle(zone, functions());
   intptr_t len = funcs.Length();
   for (intptr_t i = 0; i < len; i++) {
     func ^= funcs.At(i);
     if ((func.token_pos() <= token_pos) &&
         (token_pos <= func.end_token_pos())) {
       return func.raw();
     }
   }
   // No function found.
   return Function::null();
@@ skipping 46 matching lines @@
       }
       return Field::null();
     }
   }
   // No field found.
   return Field::null();
 }
 
 
 RawLibraryPrefix* Class::LookupLibraryPrefix(const String& name) const {
-  Isolate* isolate = Isolate::Current();
-  const Library& lib = Library::Handle(isolate, library());
-  const Object& obj = Object::Handle(isolate, lib.LookupLocalObject(name));
+  Zone* zone = Thread::Current()->zone();
+  const Library& lib = Library::Handle(zone, library());
+  const Object& obj = Object::Handle(zone, lib.LookupLocalObject(name));
   if (!obj.IsNull() && obj.IsLibraryPrefix()) {
     return LibraryPrefix::Cast(obj).raw();
   }
   return LibraryPrefix::null();
 }
 
 
 const char* Class::ToCString() const {
   const Library& lib = Library::Handle(library());
   const char* library_name = lib.IsNull() ? "" : lib.ToCString();
@@ skipping 714 matching lines @@
 
 
 void TypeArguments::SetLength(intptr_t value) const {
   ASSERT(!IsCanonical());
   // This is only safe because we create a new Smi, which does not cause
   // heap allocation.
   StoreSmi(&raw_ptr()->length_, Smi::New(value));
 }
 
 
-static void GrowCanonicalTypeArguments(Isolate* isolate, const Array& table) {
+static void GrowCanonicalTypeArguments(Thread* thread, const Array& table) {
+  Isolate* isolate = thread->isolate();
+  Zone* zone = thread->zone();
   // Last element of the array is the number of used elements.
   const intptr_t table_size = table.Length() - 1;
   const intptr_t new_table_size = table_size * 2;
-  Array& new_table = Array::Handle(isolate, Array::New(new_table_size + 1));
+  Array& new_table = Array::Handle(zone, Array::New(new_table_size + 1));
   // Copy all elements from the original table to the newly allocated
   // array.
-  TypeArguments& element = TypeArguments::Handle(isolate);
-  Object& new_element = Object::Handle(isolate);
+  TypeArguments& element = TypeArguments::Handle(zone);
+  Object& new_element = Object::Handle(zone);
   for (intptr_t i = 0; i < table_size; i++) {
     element ^= table.At(i);
     if (!element.IsNull()) {
       const intptr_t hash = element.Hash();
       ASSERT(Utils::IsPowerOfTwo(new_table_size));
       intptr_t index = hash & (new_table_size - 1);
       new_element = new_table.At(index);
       while (!new_element.IsNull()) {
         index = (index + 1) & (new_table_size - 1);  // Move to next element.
         new_element = new_table.At(index);
       }
       new_table.SetAt(index, element);
     }
   }
   // Copy used count.
   new_element = table.At(table_size);
   new_table.SetAt(new_table_size, new_element);
   // Remember the new table now.
   isolate->object_store()->set_canonical_type_arguments(new_table);
 }
 
 
-static void InsertIntoCanonicalTypeArguments(Isolate* isolate,
+static void InsertIntoCanonicalTypeArguments(Thread* thread,
                                              const Array& table,
                                              const TypeArguments& arguments,
                                              intptr_t index) {
+  Zone* zone = thread->zone();
   arguments.SetCanonical();  // Mark object as being canonical.
   table.SetAt(index, arguments);  // Remember the new element.
   // Update used count.
   // Last element of the array is the number of used elements.
   const intptr_t table_size = table.Length() - 1;
   const intptr_t used_elements =
       Smi::Value(Smi::RawCast(table.At(table_size))) + 1;
-  const Smi& used = Smi::Handle(isolate, Smi::New(used_elements));
+  const Smi& used = Smi::Handle(zone, Smi::New(used_elements));
   table.SetAt(table_size, used);
 
 #ifdef DEBUG
   // Verify that there are no duplicates.
   // Duplicates could appear if hash values are not kept constant across
   // snapshots, e.g. if class ids are not preserved by the snapshots.
   TypeArguments& other_arguments = TypeArguments::Handle();
   for (intptr_t i = 0; i < table_size; i++) {
     if ((i != index) && (table.At(i) != TypeArguments::null())) {
       other_arguments ^= table.At(i);
       if (arguments.Equals(other_arguments)) {
         // Recursive types may be equal, but have different hashes.
         ASSERT(arguments.IsRecursive());
         ASSERT(other_arguments.IsRecursive());
         ASSERT(arguments.Hash() != other_arguments.Hash());
       }
     }
   }
 #endif
 
   // Rehash if table is 75% full.
   if (used_elements > ((table_size / 4) * 3)) {
-    GrowCanonicalTypeArguments(isolate, table);
+    GrowCanonicalTypeArguments(thread, table);
   }
 }
 
 
 static intptr_t FindIndexInCanonicalTypeArguments(
-    Isolate* isolate,
+    Zone* zone,
     const Array& table,
     const TypeArguments& arguments,
     intptr_t hash) {
   // Last element of the array is the number of used elements.
   const intptr_t table_size = table.Length() - 1;
   ASSERT(Utils::IsPowerOfTwo(table_size));
   intptr_t index = hash & (table_size - 1);
 
-  TypeArguments& current = TypeArguments::Handle(isolate);
+  TypeArguments& current = TypeArguments::Handle(zone);
   current ^= table.At(index);
   while (!current.IsNull() && !current.Equals(arguments)) {
     index = (index + 1) & (table_size - 1);  // Move to next element.
     current ^= table.At(index);
   }
   return index;  // Index of element if found or slot into which to add it.
 }
 
 
 RawTypeArguments* TypeArguments::CloneUnfinalized() const {
@@ skipping 39 matching lines @@
 
 RawTypeArguments* TypeArguments::Canonicalize(TrailPtr trail) const {
   if (IsNull() || IsCanonical()) {
     ASSERT(IsOld());
     return this->raw();
   }
   const intptr_t num_types = Length();
   if (IsRaw(0, num_types)) {
     return TypeArguments::null();
   }
-  Isolate* isolate = Isolate::Current();
+  Thread* thread = Thread::Current();
+  Zone* zone = thread->zone();
+  Isolate* isolate = thread->isolate();
   ObjectStore* object_store = isolate->object_store();
-  Array& table = Array::Handle(isolate,
+  Array& table = Array::Handle(zone,
                                object_store->canonical_type_arguments());
   // Last element of the array is the number of used elements.
   const intptr_t num_used =
       Smi::Value(Smi::RawCast(table.At(table.Length() - 1)));
   const intptr_t hash = Hash();
-  intptr_t index =
-      FindIndexInCanonicalTypeArguments(isolate, table, *this, hash);
-  TypeArguments& result = TypeArguments::Handle(isolate);
+  intptr_t index = FindIndexInCanonicalTypeArguments(zone, table, *this, hash);
+  TypeArguments& result = TypeArguments::Handle(zone);
   result ^= table.At(index);
   if (result.IsNull()) {
     // Canonicalize each type argument.
-    AbstractType& type_arg = AbstractType::Handle(isolate);
+    AbstractType& type_arg = AbstractType::Handle(zone);
     for (intptr_t i = 0; i < num_types; i++) {
       type_arg = TypeAt(i);
       type_arg = type_arg.Canonicalize(trail);
       SetTypeAt(i, type_arg);
     }
     // Canonicalization of a recursive type may change its hash.
     intptr_t canonical_hash = hash;
     if (IsRecursive()) {
       canonical_hash = Hash();
     }
     // Canonicalization of the type argument's own type arguments may add an
     // entry to the table, or even grow the table, and thereby change the
     // previously calculated index.
     table = object_store->canonical_type_arguments();
     if ((canonical_hash != hash) ||
         (Smi::Value(Smi::RawCast(table.At(table.Length() - 1))) != num_used)) {
       index = FindIndexInCanonicalTypeArguments(
-          isolate, table, *this, canonical_hash);
+          zone, table, *this, canonical_hash);
       result ^= table.At(index);
     }
     if (result.IsNull()) {
       // Make sure we have an old space object and add it to the table.
       if (this->IsNew()) {
         result ^= Object::Clone(*this, Heap::kOld);
       } else {
         result ^= this->raw();
       }
       ASSERT(result.IsOld());
-      InsertIntoCanonicalTypeArguments(isolate, table, result, index);
+      InsertIntoCanonicalTypeArguments(thread, table, result, index);
     }
   }
   ASSERT(result.Equals(*this));
   ASSERT(!result.IsNull());
   ASSERT(result.IsTypeArguments());
   ASSERT(result.IsCanonical());
   return result.raw();
 }
 
 
@@ skipping 696 matching lines @@
                                  const Array& argument_names,
                                  String* error_message) const {
   const intptr_t num_named_arguments =
       argument_names.IsNull() ? 0 : argument_names.Length();
   if (!AreValidArgumentCounts(num_arguments,
                               num_named_arguments,
                               error_message)) {
     return false;
   }
   // Verify that all argument names are valid parameter names.
-  Isolate* isolate = Isolate::Current();
-  String& argument_name = String::Handle(isolate);
-  String& parameter_name = String::Handle(isolate);
+  Zone* zone = Thread::Current()->zone();
+  String& argument_name = String::Handle(zone);
+  String& parameter_name = String::Handle(zone);
   for (intptr_t i = 0; i < num_named_arguments; i++) {
     argument_name ^= argument_names.At(i);
     ASSERT(argument_name.IsSymbol());
     bool found = false;
     const intptr_t num_positional_args = num_arguments - num_named_arguments;
     const intptr_t num_parameters = NumParameters();
     for (intptr_t j = num_positional_args;
          !found && (j < num_parameters);
          j++) {
       parameter_name = ParameterNameAt(j);
@@ skipping 25 matching lines @@
                                  String* error_message) const {
   const intptr_t num_arguments = args_desc.Count();
   const intptr_t num_named_arguments = args_desc.NamedCount();
 
   if (!AreValidArgumentCounts(num_arguments,
                               num_named_arguments,
                               error_message)) {
     return false;
   }
   // Verify that all argument names are valid parameter names.
-  Isolate* isolate = Isolate::Current();
-  String& argument_name = String::Handle(isolate);
-  String& parameter_name = String::Handle(isolate);
+  Zone* zone = Thread::Current()->zone();
+  String& argument_name = String::Handle(zone);
+  String& parameter_name = String::Handle(zone);
   for (intptr_t i = 0; i < num_named_arguments; i++) {
     argument_name ^= args_desc.NameAt(i);
     ASSERT(argument_name.IsSymbol());
     bool found = false;
     const intptr_t num_positional_args = num_arguments - num_named_arguments;
     const int num_parameters = NumParameters();
     for (intptr_t j = num_positional_args;
          !found && (j < num_parameters);
          j++) {
       parameter_name = ParameterNameAt(j);
@@ skipping 658 matching lines @@
       pieces->Add(Symbols::RBracket());
     } else {
       pieces->Add(Symbols::RBrace());
     }
   }
 }
 
 
 RawInstance* Function::ImplicitStaticClosure() const {
   if (implicit_static_closure() == Instance::null()) {
-    Isolate* isolate = Isolate::Current();
+    Thread* thread = Thread::Current();
+    Isolate* isolate = thread->isolate();
+    Zone* zone = thread->zone();
     ObjectStore* object_store = isolate->object_store();
     const Context& context =
-        Context::Handle(isolate, object_store->empty_context());
+        Context::Handle(zone, object_store->empty_context());
     Instance& closure =
-        Instance::Handle(isolate, Closure::New(*this, context, Heap::kOld));
+        Instance::Handle(zone, Closure::New(*this, context, Heap::kOld));
     const char* error_str = NULL;
     closure ^= closure.CheckAndCanonicalize(&error_str);
     ASSERT(!closure.IsNull());
     set_implicit_static_closure(closure);
   }
   return implicit_static_closure();
 }
 
 
 RawInstance* Function::ImplicitInstanceClosure(const Instance& receiver) const {
@@ skipping 1494 matching lines @@
 }
 
 
 RawTokenStream* TokenStream::New(intptr_t len) {
   if (len < 0 || len > kMaxElements) {
     // This should be caught before we reach here.
     FATAL1("Fatal error in TokenStream::New: invalid len %" Pd "\n", len);
   }
   uint8_t* data = reinterpret_cast<uint8_t*>(::malloc(len));
   ASSERT(data != NULL);
-  Isolate* isolate = Isolate::Current();
+  Zone* zone = Thread::Current()->zone();
   const ExternalTypedData& stream = ExternalTypedData::Handle(
-      isolate,
+      zone,
       ExternalTypedData::New(kExternalTypedDataUint8ArrayCid,
                              data, len, Heap::kOld));
   stream.AddFinalizer(data, DataFinalizer);
-  const TokenStream& result = TokenStream::Handle(isolate, TokenStream::New());
+  const TokenStream& result = TokenStream::Handle(zone, TokenStream::New());
   result.SetStream(stream);
   return result.raw();
 }
 
 
 // CompressedTokenMap maps String and LiteralToken keys to Smi values.
 // It also supports lookup by Scanner::TokenDescriptor.
 class CompressedTokenTraits {
  public:
   static bool IsMatch(const Scanner::TokenDescriptor& descriptor,
@@ skipping 106 matching lines @@
   uint8_t* buffer_;
   WriteStream stream_;
   CompressedTokenMap tokens_;
 
   DISALLOW_COPY_AND_ASSIGN(CompressedTokenStreamData);
 };
 
 
 RawTokenStream* TokenStream::New(const Scanner::GrowableTokenStream& tokens,
                                  const String& private_key) {
-  Isolate* isolate = Isolate::Current();
+  Zone* zone = Thread::Current()->zone();
   // Copy the relevant data out of the scanner into a compressed stream of
   // tokens.
   CompressedTokenStreamData data;
   intptr_t len = tokens.length();
   for (intptr_t i = 0; i < len; i++) {
     Scanner::TokenDescriptor token = tokens[i];
     if (token.kind == Token::kIDENT) {  // Identifier token.
       data.AddIdentToken(token.literal);
     } else if (Token::NeedsLiteralToken(token.kind)) {  // Literal token.
       data.AddLiteralToken(token);
     } else {  // Keyword, pseudo keyword etc.
       ASSERT(token.kind < Token::kNumTokens);
       data.AddSimpleToken(token.kind);
     }
   }
   data.AddSimpleToken(Token::kEOS);  // End of stream.
 
   // Create and setup the token stream object.
   const ExternalTypedData& stream = ExternalTypedData::Handle(
-      isolate,
+      zone,
       ExternalTypedData::New(kExternalTypedDataUint8ArrayCid,
                              data.GetStream(), data.Length(), Heap::kOld));
   stream.AddFinalizer(data.GetStream(), DataFinalizer);
-  const TokenStream& result = TokenStream::Handle(isolate, New());
+  const TokenStream& result = TokenStream::Handle(zone, New());
   result.SetPrivateKey(private_key);
   const Array& token_objects =
-      Array::Handle(isolate, data.MakeTokenObjectsArray());
+      Array::Handle(zone, data.MakeTokenObjectsArray());
   {
     NoSafepointScope no_safepoint;
     result.SetStream(stream);
     result.SetTokenObjects(token_objects);
   }
   return result.raw();
 }
 
 
 const char* TokenStream::ToCString() const {
@@ skipping 167 matching lines @@
 }
 
 
 RawString* Script::GenerateSource() const {
   const TokenStream& token_stream = TokenStream::Handle(tokens());
   return token_stream.GenerateSource();
 }
 
 
 RawGrowableObjectArray* Script::GenerateLineNumberArray() const {
-  Isolate* isolate = Isolate::Current();
+  Zone* zone = Thread::Current()->zone();
   const GrowableObjectArray& info =
-      GrowableObjectArray::Handle(isolate, GrowableObjectArray::New());
-  const String& source = String::Handle(isolate, Source());
+      GrowableObjectArray::Handle(zone, GrowableObjectArray::New());
+  const String& source = String::Handle(zone, Source());
   const String& key = Symbols::Empty();
-  const Object& line_separator = Object::Handle(isolate);
-  const TokenStream& tkns = TokenStream::Handle(isolate, tokens());
-  Smi& value = Smi::Handle(isolate);
-  String& tokenValue = String::Handle(isolate);
+  const Object& line_separator = Object::Handle(zone);
+  const TokenStream& tkns = TokenStream::Handle(zone, tokens());
+  Smi& value = Smi::Handle(zone);
+  String& tokenValue = String::Handle(zone);
   ASSERT(!tkns.IsNull());
   TokenStream::Iterator tkit(tkns, 0, TokenStream::Iterator::kAllTokens);
   int current_line = -1;
   Scanner s(source, key);
   s.Scan();
   bool skippedNewline = false;
   while (tkit.CurrentTokenKind() != Token::kEOS) {
     if (tkit.CurrentTokenKind() == Token::kNEWLINE) {
       // Skip newlines from the token stream.
       skippedNewline = true;
@@ skipping 322 matching lines @@
   return result.raw();
 }
 
 
 const char* Script::ToCString() const {
   return "Script";
 }
 
 
 RawLibrary* Script::FindLibrary() const {
-  Isolate* isolate = Isolate::Current();
+  Thread* thread = Thread::Current();
+  Zone* zone = thread->zone();
+  Isolate* isolate = thread->isolate();
   const GrowableObjectArray& libs = GrowableObjectArray::Handle(
-      isolate, isolate->object_store()->libraries());
+      zone, isolate->object_store()->libraries());
   Library& lib = Library::Handle();
   Array& scripts = Array::Handle();
   for (intptr_t i = 0; i < libs.Length(); i++) {
     lib ^= libs.At(i);
     scripts = lib.LoadedScripts();
     for (intptr_t j = 0; j < scripts.Length(); j++) {
       if (scripts.At(j) == raw()) {
         return lib.raw();
       }
     }
@@ skipping 226 matching lines @@
 
 typedef UnorderedHashSet<LibraryUrlTraits> LibraryLoadErrorSet;
 
 
 RawInstance* Library::TransitiveLoadError() const {
   if (LoadError() != Instance::null()) {
     return LoadError();
   }
   Thread* thread = Thread::Current();
   Isolate* isolate = thread->isolate();
+  Zone* zone = thread->zone();
   ObjectStore* object_store = isolate->object_store();
   LibraryLoadErrorSet set(object_store->library_load_error_table());
   bool present = false;
   if (set.GetOrNull(*this, &present) != Object::null()) {
     object_store->set_library_load_error_table(set.Release());
     return Instance::null();
   }
   // Ensure we don't repeatedly visit the same library again.
   set.Insert(*this);
   object_store->set_library_load_error_table(set.Release());
   intptr_t num_imp = num_imports();
-  Library& lib = Library::Handle(isolate);
-  Instance& error = Instance::Handle(isolate);
+  Library& lib = Library::Handle(zone);
+  Instance& error = Instance::Handle(zone);
   for (intptr_t i = 0; i < num_imp; i++) {
     HANDLESCOPE(thread);
     lib = ImportLibraryAt(i);
     error = lib.TransitiveLoadError();
     if (!error.IsNull()) {
       break;
     }
   }
   return error.raw();
 }
@@ skipping 551 matching lines @@
 RawFunction* Library::LookupLocalFunction(const String& name) const {
   Object& obj = Object::Handle(LookupLocalObjectAllowPrivate(name));
   if (obj.IsFunction()) {
     return Function::Cast(obj).raw();
   }
   return Function::null();
 }
 
 
 RawObject* Library::LookupLocalObjectAllowPrivate(const String& name) const {
-  Isolate* isolate = Isolate::Current();
-  Object& obj = Object::Handle(isolate, Object::null());
+  Thread* thread = Thread::Current();
+  Zone* zone = thread->zone();
+  Object& obj = Object::Handle(zone, Object::null());
   obj = LookupLocalObject(name);
   if (obj.IsNull() && ShouldBePrivate(name)) {
-    String& private_name = String::Handle(isolate, PrivateName(name));
+    String& private_name = String::Handle(zone, PrivateName(name));
     obj = LookupLocalObject(private_name);
   }
   return obj.raw();
 }
 
 
 RawObject* Library::LookupObjectAllowPrivate(const String& name) const {
   // First check if name is found in the local scope of the library.
   Object& obj = Object::Handle(LookupLocalObjectAllowPrivate(name));
   if (!obj.IsNull()) {
@@ skipping 78 matching lines @@
   if (obj.IsClass()) {
     return Class::Cast(obj).raw();
   }
   return Class::null();
 }
 
 
 RawClass* Library::LookupClassAllowPrivate(const String& name) const {
   // See if the class is available in this library or in the top level
   // scope of any imported library.
-  Isolate* isolate = Isolate::Current();
-  const Class& cls = Class::Handle(isolate, LookupClass(name));
+  Zone* zone = Thread::Current()->zone();
+  const Class& cls = Class::Handle(zone, LookupClass(name));
   if (!cls.IsNull()) {
     return cls.raw();
   }
 
   // Now try to lookup the class using its private name, but only in
   // this library (not in imported libraries).
   if (ShouldBePrivate(name)) {
-    String& private_name = String::Handle(isolate, PrivateName(name));
+    String& private_name = String::Handle(zone, PrivateName(name));
     const Object& obj = Object::Handle(LookupLocalObject(private_name));
     if (obj.IsClass()) {
       return Class::Cast(obj).raw();
     }
   }
   return Class::null();
 }
 
 
 RawLibraryPrefix* Library::LookupLocalLibraryPrefix(const String& name) const {
@@ skipping 31 matching lines @@
 RawNamespace* Library::ImportAt(intptr_t index) const {
   if ((index < 0) || index >= num_imports()) {
     return Namespace::null();
   }
   const Array& import_list = Array::Handle(imports());
   return Namespace::RawCast(import_list.At(index));
 }
 
 
 bool Library::ImportsCorelib() const {
-  Isolate* isolate = Isolate::Current();
-  Library& imported = Library::Handle(isolate);
+  Zone* zone = Thread::Current()->zone();
+  Library& imported = Library::Handle(zone);
   intptr_t count = num_imports();
   for (int i = 0; i < count; i++) {
     imported = ImportLibraryAt(i);
     if (imported.IsCoreLibrary()) {
       return true;
     }
   }
-  LibraryPrefix& prefix = LibraryPrefix::Handle(isolate);
+  LibraryPrefix& prefix = LibraryPrefix::Handle(zone);
   LibraryPrefixIterator it(*this);
   while (it.HasNext()) {
     prefix = it.GetNext();
     count = prefix.num_imports();
     for (int i = 0; i < count; i++) {
       imported = prefix.GetLibrary(i);
       if (imported.IsCoreLibrary()) {
         return true;
       }
     }
@@ skipping 177 matching lines @@
                 fld_cnt);
     cls_name = Symbols::New(name_buffer);
     Class::NewNativeWrapper(native_flds_lib, cls_name, fld_cnt);
   }
   native_flds_lib.SetLoaded();
 }
 
 
 // Returns library with given url in current isolate, or NULL.
 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());
+  Thread* thread = Thread::Current();
+  Zone* zone = thread->zone();
+  Isolate* isolate = thread->isolate();
+  Library& lib = Library::Handle(zone, Library::null());
+  String& lib_url = String::Handle(zone, String::null());
   GrowableObjectArray& libs = GrowableObjectArray::Handle(
-      isolate, isolate->object_store()->libraries());
+      zone, isolate->object_store()->libraries());
   for (int i = 0; i < libs.Length(); i++) {
     lib ^= libs.At(i);
     lib_url ^= lib.url();
     if (lib_url.Equals(url)) {
       return lib.raw();
     }
   }
   return Library::null();
 }
 
@@ skipping 308 matching lines @@
     import ^= imports.At(index);
     return import.library();
   }
   return Library::null();
 }
 
 
 RawInstance* LibraryPrefix::LoadError() const {
   Thread* thread = Thread::Current();
   Isolate* isolate = thread->isolate();
+  Zone* zone = thread->zone();
   ObjectStore* object_store = isolate->object_store();
   GrowableObjectArray& libs =
-      GrowableObjectArray::Handle(isolate, object_store->libraries());
+      GrowableObjectArray::Handle(zone, object_store->libraries());
   ASSERT(!libs.IsNull());
   LibraryLoadErrorSet set(HashTables::New<LibraryLoadErrorSet>(libs.Length()));
   object_store->set_library_load_error_table(set.Release());
-  Library& lib = Library::Handle(isolate);
-  Instance& error = Instance::Handle(isolate);
+  Library& lib = Library::Handle(zone);
+  Instance& error = Instance::Handle(zone);
   for (int32_t i = 0; i < num_imports(); i++) {
     lib = GetLibrary(i);
     ASSERT(!lib.IsNull());
     HANDLESCOPE(thread);
     error = lib.TransitiveLoadError();
     if (!error.IsNull()) {
       break;
     }
   }
   object_store->set_library_load_error_table(Object::empty_array());
@@ skipping 108 matching lines @@
   // loading. Once all outstanding load requests have completed, the embedder
   // will call the core library to:
   // - invalidate dependent code of this prefix;
   // - mark this prefixes as loaded;
   // - complete the future associated with this prefix.
   const Library& deferred_lib = Library::Handle(GetLibrary(0));
   if (deferred_lib.Loaded()) {
     this->set_is_loaded();
     return true;
   } else if (deferred_lib.LoadNotStarted()) {
-    Isolate* isolate = Isolate::Current();
+    Thread* thread = Thread::Current();
+    Isolate* isolate = thread->isolate();
     Api::Scope api_scope(isolate);
+    Zone* zone = thread->zone();
     deferred_lib.SetLoadRequested();
     const GrowableObjectArray& pending_deferred_loads =
         GrowableObjectArray::Handle(
             isolate->object_store()->pending_deferred_loads());
     pending_deferred_loads.Add(deferred_lib);
-    const String& lib_url = String::Handle(isolate, deferred_lib.url());
+    const String& lib_url = String::Handle(zone, deferred_lib.url());
     Dart_LibraryTagHandler handler = isolate->library_tag_handler();
     handler(Dart_kImportTag,
             Api::NewHandle(isolate, importer()),
             Api::NewHandle(isolate, lib_url.raw()));
   } else {
     // Another load request is in flight.
     ASSERT(deferred_lib.LoadRequested());
   }
   return false;  // Load request not yet completed.
 }
@@ skipping 212 matching lines @@
     return true;
   }
   // The name is not filtered out.
   return false;
 }
 
 
 // Look up object with given name in library and filter out hidden
 // names. Also look up getters and setters.
 RawObject* Namespace::Lookup(const String& name) const {
-  Isolate* isolate = Isolate::Current();
-  const Library& lib = Library::Handle(isolate, library());
+  Zone* zone = Thread::Current()->zone();
+  const Library& lib = Library::Handle(zone, library());
   intptr_t ignore = 0;
 
   // Lookup the name in the library's symbols.
-  Object& obj = Object::Handle(isolate, lib.LookupEntry(name, &ignore));
+  Object& obj = Object::Handle(zone, lib.LookupEntry(name, &ignore));
   if (!Field::IsGetterName(name) &&
       !Field::IsSetterName(name) &&
       (obj.IsNull() || obj.IsLibraryPrefix())) {
     const String& getter_name = String::Handle(Field::LookupGetterSymbol(name));
     if (!getter_name.IsNull()) {
       obj = lib.LookupEntry(getter_name, &ignore);
     }
     if (obj.IsNull()) {
       const String& setter_name =
           String::Handle(Field::LookupSetterSymbol(name));
@@ skipping 3754 matching lines @@
 bool Instance::IsInstanceOf(const AbstractType& other,
                             const TypeArguments& other_instantiator,
                             Error* bound_error) const {
   ASSERT(other.IsFinalized());
   ASSERT(!other.IsDynamicType());
   ASSERT(!other.IsMalformed());
   ASSERT(!other.IsMalbounded());
   if (other.IsVoidType()) {
     return false;
   }
-  Isolate* isolate = Isolate::Current();
-  const Class& cls = Class::Handle(isolate, clazz());
-  TypeArguments& type_arguments = TypeArguments::Handle(isolate);
+  Zone* zone = Thread::Current()->zone();
+  const Class& cls = Class::Handle(zone, clazz());
+  TypeArguments& type_arguments = TypeArguments::Handle(zone);
   if (cls.NumTypeArguments() > 0) {
     type_arguments = GetTypeArguments();
     ASSERT(type_arguments.IsNull() || type_arguments.IsCanonical());
     // The number of type arguments in the instance must be greater or equal to
     // 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 subclass of the class
     // defining the closure. Truncating the vector to the correct length on
     // instantiation is unnecessary. The vector may therefore be longer.
     // Also, an optimization reuses the type argument vector of the instantiator
     // of generic instances when its layout is compatible.
     ASSERT(type_arguments.IsNull() ||
            (type_arguments.Length() >= cls.NumTypeArguments()));
   }
-  Class& other_class = Class::Handle(isolate);
-  TypeArguments& other_type_arguments = TypeArguments::Handle(isolate);
+  Class& other_class = Class::Handle(zone);
+  TypeArguments& other_type_arguments = TypeArguments::Handle(zone);
   // Note that we may encounter a bound error in checked mode.
   if (!other.IsInstantiated()) {
     const AbstractType& instantiated_other = AbstractType::Handle(
-        isolate, other.InstantiateFrom(other_instantiator, bound_error));
+        zone, other.InstantiateFrom(other_instantiator, bound_error));
     if ((bound_error != NULL) && !bound_error->IsNull()) {
       ASSERT(Isolate::Current()->flags().type_checks());
       return false;
     }
     other_class = instantiated_other.type_class();
     other_type_arguments = instantiated_other.arguments();
   } else {
     other_class = other.type_class();
     other_type_arguments = other.arguments();
   }
@@ skipping 1166 matching lines @@
   return clone.raw();
 }
 
 
 RawAbstractType* Type::Canonicalize(TrailPtr trail) const {
   ASSERT(IsFinalized());
   if (IsCanonical() || IsMalformed()) {
     ASSERT(IsMalformed() || TypeArguments::Handle(arguments()).IsOld());
     return this->raw();
   }
-  Isolate* isolate = Isolate::Current();
-  Type& type = Type::Handle(isolate);
-  const Class& cls = Class::Handle(isolate, type_class());
+  Thread* thread = Thread::Current();
+  Zone* zone = thread->zone();
+  Isolate* isolate = thread->isolate();
+  Type& type = Type::Handle(zone);
+  const Class& cls = Class::Handle(zone, type_class());
   if (cls.raw() == Object::dynamic_class() && (isolate != Dart::vm_isolate())) {
     return Object::dynamic_type();
   }
   // Fast canonical lookup/registry for simple types.
   if (cls.NumTypeArguments() == 0) {
     type = cls.CanonicalType();
     if (type.IsNull()) {
       ASSERT(!cls.raw()->IsVMHeapObject() || (isolate == Dart::vm_isolate()));
       cls.set_canonical_types(*this);
       SetCanonical();
       return this->raw();
     }
     ASSERT(this->Equals(type));
     ASSERT(type.IsCanonical());
     return type.raw();
   }
 
-  Array& canonical_types = Array::Handle(isolate);
+  Array& canonical_types = Array::Handle(zone);
   canonical_types ^= cls.canonical_types();
   if (canonical_types.IsNull()) {
     canonical_types = empty_array().raw();
   }
   intptr_t length = 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.
   intptr_t index = 1;  // Slot 0 is reserved for CanonicalType().
   while (index < length) {
     type ^= canonical_types.At(index);
     if (type.IsNull()) {
       break;
     }
     ASSERT(type.IsFinalized());
     if (this->Equals(type)) {
       ASSERT(type.IsCanonical());
       return type.raw();
     }
     index++;
   }
   // The type was not found in the table. It is not canonical yet.
 
   // Canonicalize the type arguments.
-  TypeArguments& type_args = TypeArguments::Handle(isolate, arguments());
+  TypeArguments& type_args = TypeArguments::Handle(zone, arguments());
   // In case the type is first canonicalized at runtime, its type argument
   // vector may be longer than necessary. This is not an issue.
   ASSERT(type_args.IsNull() || (type_args.Length() >= cls.NumTypeArguments()));
   type_args = type_args.Canonicalize(trail);
   set_arguments(type_args);
 
   // Canonicalizing the type arguments may have changed the index, may have
   // grown the table, or may even have canonicalized this type.
   canonical_types ^= cls.canonical_types();
   if (canonical_types.IsNull()) {
@@ skipping 13 matching lines @@
     index++;
   }
 
   // The type needs to be added to the list. Grow the list if it is full.
   if (index >= length) {
     ASSERT((index == length) || ((index == 1) && (length == 0)));
     const intptr_t new_length = (length > 64) ?
         (length + 64) :
         ((length == 0) ? 2 : (length * 2));
     const Array& new_canonical_types = Array::Handle(
-        isolate, Array::Grow(canonical_types, new_length, Heap::kOld));
+        zone, Array::Grow(canonical_types, new_length, Heap::kOld));
     cls.set_canonical_types(new_canonical_types);
     canonical_types = new_canonical_types.raw();
   }
   canonical_types.SetAt(index, *this);
   if ((index == 1) && cls.IsCanonicalSignatureClass()) {
     canonical_types.SetAt(0, *this);  // Also set canonical signature type at 0.
 #ifdef DEBUG
     // Verify that the first canonical type is the signature type by checking
     // that the type argument vector of the canonical type ends with the
     // uninstantiated type parameters of the signature class. Note that these
     // type parameters may be bounded if the super class of the owner class
     // declares bounds.
     // The signature type is finalized during class finalization, before the
     // optimizer may canonicalize instantiated function types of the same
     // signature class.
     // Although the signature class extends class Instance, the type arguments
     // of the super class of the owner class of its signature function will be
     // prepended to the type argument vector during class finalization.
     const TypeArguments& type_params =
-      TypeArguments::Handle(isolate, cls.type_parameters());
+        TypeArguments::Handle(zone, cls.type_parameters());
     const intptr_t num_type_params = cls.NumTypeParameters();
     const intptr_t num_type_args = cls.NumTypeArguments();
-    AbstractType& type_arg = AbstractType::Handle(isolate);
-    TypeParameter& type_param = TypeParameter::Handle(isolate);
+    AbstractType& type_arg = AbstractType::Handle(zone);
+    TypeParameter& type_param = TypeParameter::Handle(zone);
     for (intptr_t i = 0; i < num_type_params; i++) {
       type_arg = type_args.TypeAt(num_type_args - num_type_params + i);
       while (type_arg.IsBoundedType()) {
         type_arg = BoundedType::Cast(type_arg).type();
       }
       type_param ^= type_params.TypeAt(i);
       ASSERT(type_arg.Equals(type_param));
     }
 #endif
   }
@@ skipping 1623 matching lines @@
     ASSERT(!digits_.IsNull());
     set_digits(digits_);
   } else {
     ASSERT(digits() == TypedData::EmptyUint32Array(Isolate::Current()));
   }
   return true;
 }
 
 
 RawBigint* Bigint::New(Heap::Space space) {
-  Isolate* isolate = Isolate::Current();
+  Thread* thread = Thread::Current();
+  Zone* zone = thread->zone();
+  Isolate* isolate = thread->isolate();
   ASSERT(isolate->object_store()->bigint_class() != Class::null());
-  Bigint& result = Bigint::Handle(isolate);
+  Bigint& result = Bigint::Handle(zone);
   {
     RawObject* raw = Object::Allocate(Bigint::kClassId,
                                       Bigint::InstanceSize(),
                                       space);
     NoSafepointScope no_safepoint;
     result ^= raw;
   }
   result.SetNeg(false);
   result.SetUsed(0);
   result.set_digits(
-      TypedData::Handle(isolate, TypedData::EmptyUint32Array(isolate)));
+      TypedData::Handle(zone, TypedData::EmptyUint32Array(isolate)));
   return result.raw();
 }
 
 
 RawBigint* Bigint::New(bool neg, intptr_t used, const TypedData& digits,
                        Heap::Space space) {
   ASSERT((used == 0) ||
          (!digits.IsNull() && (digits.Length() >= (used + (used & 1)))));
-  Isolate* isolate = Isolate::Current();
+  Thread* thread = Thread::Current();
+  Zone* zone = thread->zone();
+  Isolate* isolate = thread->isolate();
   ASSERT(isolate->object_store()->bigint_class() != Class::null());
-  Bigint& result = Bigint::Handle(isolate);
+  Bigint& result = Bigint::Handle(zone);
   {
     RawObject* raw = Object::Allocate(Bigint::kClassId,
                                       Bigint::InstanceSize(),
                                       space);
     NoSafepointScope no_safepoint;
     result ^= raw;
   }
   // Clamp the digits array.
   while ((used > 0) && (digits.GetUint32((used - 1) << 2) == 0)) {
     --used;
   }
   if (used > 0) {
     if ((used & 1) != 0) {
       // Set leading zero for 64-bit processing of digit pairs.
       digits.SetUint32(used << 2, 0);
     }
     result.set_digits(digits);
   } else {
     neg = false;
     result.set_digits(
-        TypedData::Handle(isolate, TypedData::EmptyUint32Array(isolate)));
+        TypedData::Handle(zone, TypedData::EmptyUint32Array(isolate)));
   }
   result.SetNeg(neg);
   result.SetUsed(used);
   return result.raw();
 }
 
 
 RawBigint* Bigint::NewFromInt64(int64_t value, Heap::Space space) {
   const TypedData& digits = TypedData::Handle(NewDigits(2, space));
   bool neg;
@@ skipping 2464 matching lines @@
       element = At(index);
       jsarr.AddValue(element);
     }
   }
 }
 
 
 RawArray* Array::Grow(const Array& source,
                       intptr_t new_length,
                       Heap::Space space) {
-  Isolate* isolate = Isolate::Current();
-  const Array& result = Array::Handle(isolate, Array::New(new_length, space));
+  Zone* zone = Thread::Current()->zone();
+  const Array& result = Array::Handle(zone, Array::New(new_length, space));
   intptr_t len = 0;
   if (!source.IsNull()) {
     len = source.Length();
     result.SetTypeArguments(
-        TypeArguments::Handle(isolate, source.GetTypeArguments()));
+        TypeArguments::Handle(zone, source.GetTypeArguments()));
   }
   ASSERT(new_length >= len);  // Cannot copy 'source' into new array.
   ASSERT(new_length != len);  // Unnecessary copying of array.
-  PassiveObject& obj = PassiveObject::Handle(isolate);
+  PassiveObject& obj = PassiveObject::Handle(zone);
   for (int i = 0; i < len; i++) {
     obj = source.At(i);
     result.SetAt(i, obj);
   }
   return result.raw();
 }
 
 
 RawArray* Array::MakeArray(const GrowableObjectArray& growable_array) {
   ASSERT(!growable_array.IsNull());
   intptr_t used_len = growable_array.Length();
   // Get the type arguments and prepare to copy them.
   const TypeArguments& type_arguments =
       TypeArguments::Handle(growable_array.GetTypeArguments());
   if ((used_len == 0) && (type_arguments.IsNull())) {
     // This is a raw List (as in no type arguments), so we can return the
     // simple empty array.
     return Object::empty_array().raw();
   }
   intptr_t capacity_len = growable_array.Capacity();
-  Isolate* isolate = Isolate::Current();
-  const Array& array = Array::Handle(isolate, growable_array.data());
+  Zone* zone = Thread::Current()->zone();
+  const Array& array = Array::Handle(zone, growable_array.data());
   array.SetTypeArguments(type_arguments);
   intptr_t capacity_size = Array::InstanceSize(capacity_len);
   intptr_t used_size = Array::InstanceSize(used_len);
   NoSafepointScope no_safepoint;
 
   // 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.
   Object::MakeUnusedSpaceTraversable(array, capacity_size, used_size);
 
@@ skipping 655 matching lines @@
 }
 
 
 RawTypedData* TypedData::EmptyUint32Array(Isolate* isolate) {
   ASSERT(isolate != NULL);
   ASSERT(isolate->object_store() != NULL);
   if (isolate->object_store()->empty_uint32_array() != TypedData::null()) {
     // Already created.
     return isolate->object_store()->empty_uint32_array();
   }
-  const TypedData& array = TypedData::Handle(isolate,
+  const TypedData& array = TypedData::Handle(isolate->current_zone(),
       TypedData::New(kTypedDataUint32ArrayCid, 0, Heap::kOld));
   isolate->object_store()->set_empty_uint32_array(array);
   return array.raw();
 }
 
 
 const char* TypedData::ToCString() const {
   return "TypedData";
 }
 
@@ skipping 91 matching lines @@
 
 void Capability::PrintJSONImpl(JSONStream* stream, bool ref) const {
   Instance::PrintJSONImpl(stream, ref);
 }
 
 
 RawReceivePort* ReceivePort::New(Dart_Port id,
                                  bool is_control_port,
                                  Heap::Space space) {
   ASSERT(id != ILLEGAL_PORT);
-  Isolate* isolate = Isolate::Current();
+  Thread* thread = Thread::Current();
+  Zone* zone = thread->zone();
   const SendPort& send_port =
-      SendPort::Handle(isolate, SendPort::New(id, isolate->origin_id()));
+      SendPort::Handle(zone, SendPort::New(id, thread->isolate()->origin_id()));
 
-  ReceivePort& result = ReceivePort::Handle(isolate);
+  ReceivePort& result = ReceivePort::Handle(zone);
   {
     RawObject* raw = Object::Allocate(ReceivePort::kClassId,
                                       ReceivePort::InstanceSize(),
                                       space);
     NoSafepointScope no_safepoint;
     result ^= raw;
     result.StorePointer(&result.raw_ptr()->send_port_, send_port.raw());
   }
   if (is_control_port) {
     PortMap::SetPortState(id, PortMap::kControlPort);
@@ skipping 534 matching lines @@
     NoSafepointScope no_safepoint;
     result ^= raw;
   }
   result.set_label(label);
   AddTagToIsolate(isolate, result);
   return result.raw();
 }
 
 
 RawUserTag* UserTag::DefaultTag() {
-  Isolate* isolate = Isolate::Current();
+  Thread* thread = Thread::Current();
+  Zone* zone = thread->zone();
+  Isolate* isolate = thread->isolate();
   ASSERT(isolate != NULL);
   if (isolate->default_tag() != UserTag::null()) {
     // Already created.
     return isolate->default_tag();
   }
   // Create default tag.
-  const UserTag& result = UserTag::Handle(isolate,
+  const UserTag& result = UserTag::Handle(zone,
                                           UserTag::New(Symbols::Default()));
   ASSERT(result.tag() == UserTags::kDefaultUserTag);
   isolate->set_default_tag(result);
   return result.raw();
 }
 
 
 RawUserTag* UserTag::FindTagInIsolate(Isolate* isolate, const String& label) {
   ASSERT(isolate->tag_table() != GrowableObjectArray::null());
   const GrowableObjectArray& tag_table = GrowableObjectArray::Handle(
-      isolate, isolate->tag_table());
-  UserTag& other = UserTag::Handle(isolate);
-  String& tag_label = String::Handle(isolate);
+      isolate->current_zone(), isolate->tag_table());
+  UserTag& other = UserTag::Handle(isolate->current_zone());
+  String& tag_label = String::Handle(isolate->current_zone());
   for (intptr_t i = 0; i < tag_table.Length(); i++) {
     other ^= tag_table.At(i);
     ASSERT(!other.IsNull());
     tag_label ^= other.label();
     ASSERT(!tag_label.IsNull());
     if (tag_label.Equals(label)) {
       return other.raw();
     }
   }
   return UserTag::null();
 }
 
 
 void UserTag::AddTagToIsolate(Isolate* isolate, const UserTag& tag) {
   ASSERT(isolate->tag_table() != GrowableObjectArray::null());
   const GrowableObjectArray& tag_table = GrowableObjectArray::Handle(
-      isolate, isolate->tag_table());
+      isolate->current_zone(), isolate->tag_table());
   ASSERT(!TagTableIsFull(isolate));
 #if defined(DEBUG)
   // Verify that no existing tag has the same tag id.
-  UserTag& other = UserTag::Handle(isolate);
+  UserTag& other = UserTag::Handle(isolate->current_zone());
   for (intptr_t i = 0; i < tag_table.Length(); i++) {
     other ^= tag_table.At(i);
     ASSERT(!other.IsNull());
     ASSERT(tag.tag() != other.tag());
   }
 #endif
   // Generate the UserTag tag id by taking the length of the isolate's
   // tag table + kUserTagIdOffset.
   uword tag_id = tag_table.Length() + UserTags::kUserTagIdOffset;
   ASSERT(tag_id >= UserTags::kUserTagIdOffset);
   ASSERT(tag_id < (UserTags::kUserTagIdOffset + UserTags::kMaxUserTags));
   tag.set_tag(tag_id);
   tag_table.Add(tag);
 }
 
 
 bool UserTag::TagTableIsFull(Isolate* isolate) {
   ASSERT(isolate->tag_table() != GrowableObjectArray::null());
   const GrowableObjectArray& tag_table = GrowableObjectArray::Handle(
-      isolate, isolate->tag_table());
+      isolate->current_zone(), isolate->tag_table());
   ASSERT(tag_table.Length() <= UserTags::kMaxUserTags);
   return tag_table.Length() == UserTags::kMaxUserTags;
 }
 
 
 RawUserTag* UserTag::FindTagById(uword tag_id) {
-  Isolate* isolate = Isolate::Current();
+  Thread* thread = Thread::Current();
+  Zone* zone = thread->zone();
+  Isolate* isolate = thread->isolate();
   ASSERT(isolate->tag_table() != GrowableObjectArray::null());
   const GrowableObjectArray& tag_table = GrowableObjectArray::Handle(
-      isolate, isolate->tag_table());
-  UserTag& tag = UserTag::Handle(isolate);
+      zone, isolate->tag_table());
+  UserTag& tag = UserTag::Handle(zone);
   for (intptr_t i = 0; i < tag_table.Length(); i++) {
     tag ^= tag_table.At(i);
     if (tag.tag() == tag_id) {
       return tag.raw();
     }
   }
   return UserTag::null();
 }
 
 
 const char* UserTag::ToCString() const {
   const String& tag_label = String::Handle(label());
   return tag_label.ToCString();
 }
 
 
 void UserTag::PrintJSONImpl(JSONStream* stream, bool ref) const {
   Instance::PrintJSONImpl(stream, ref);
 }
 
 
 }  // namespace dart