Remove some Isolate::current_zone() calls, as it gets the zone from mutator thread not the current thread

BUG=
R=zra@google.com

Review URL: https://codereview.chromium.org/1414493003 .

runtime/lib/bool.cc

@@ -21,7 +21,7 @@ DEFINE_NATIVE_ENTRY(Bool_fromEnvironment, 3) {
   GET_NATIVE_ARGUMENT(Bool, default_value, arguments->NativeArgAt(2));
   // Call the embedder to supply us with the environment.
   const String& env_value =
-      String::Handle(Api::CallEnvironmentCallback(isolate, name));
+      String::Handle(Api::CallEnvironmentCallback(thread, name));
   if (!env_value.IsNull()) {
     if (Symbols::True().Equals(env_value)) {
       return Bool::True().raw();

runtime/lib/integers.cc

@@ -237,7 +237,7 @@ DEFINE_NATIVE_ENTRY(Integer_fromEnvironment, 3) {
   GET_NATIVE_ARGUMENT(Integer, default_value, arguments->NativeArgAt(2));
   // Call the embedder to supply us with the environment.
   const String& env_value =
-      String::Handle(Api::CallEnvironmentCallback(isolate, name));
+      String::Handle(Api::CallEnvironmentCallback(thread, name));
   if (!env_value.IsNull()) {
     const Integer& result = Integer::Handle(ParseInteger(env_value));
     if (!result.IsNull()) {

runtime/lib/string.cc

@@ -20,7 +20,7 @@ DEFINE_NATIVE_ENTRY(String_fromEnvironment, 3) {
   GET_NATIVE_ARGUMENT(String, default_value, arguments->NativeArgAt(2));
   // Call the embedder to supply us with the environment.
   const String& env_value =
-      String::Handle(Api::CallEnvironmentCallback(isolate, name));
+      String::Handle(Api::CallEnvironmentCallback(thread, name));
   if (!env_value.IsNull()) {
     return Symbols::New(env_value);
   }

runtime/vm/benchmark_test.cc

@@ -41,8 +41,7 @@ BENCHMARK(CorelibCompileAll) {
   bin::Builtin::SetNativeResolver(bin::Builtin::kIOLibrary);
   Timer timer(true, "Compile all of Core lib benchmark");
   timer.Start();
-  const Error& error = Error::Handle(benchmark->isolate()->current_zone(),
+  const Error& error = Error::Handle(Library::CompileAll());
-                                     Library::CompileAll());
   if (!error.IsNull()) {
     OS::PrintErr("Unexpected error in CorelibCompileAll benchmark:\n%s",
                  error.ToErrorCString());
@@ -61,8 +60,7 @@ BENCHMARK(CorelibCompilerStats) {
   stats->EnableBenchmark();
   Timer timer(true, "Compiler stats compiling all of Core lib");
   timer.Start();
-  const Error& error = Error::Handle(benchmark->isolate()->current_zone(),
+  const Error& error = Error::Handle(Library::CompileAll());
-                                     Library::CompileAll());
   if (!error.IsNull()) {
     OS::PrintErr("Unexpected error in CorelibCompileAll benchmark:\n%s",
                  error.ToErrorCString());

runtime/vm/code_generator.cc

@@ -1452,7 +1452,7 @@ DEFINE_RUNTIME_ENTRY(OptimizeInvokedFunction, 1) {
     // prevent recursive triggering of function optimization.
     function.set_usage_counter(0);
     if (FLAG_background_compilation) {
-      BackgroundCompiler::EnsureInit(isolate);
+      BackgroundCompiler::EnsureInit(thread);
       ASSERT(isolate->background_compiler() != NULL);
       isolate->background_compiler()->CompileOptimized(function);
       // Continue in the same code.

runtime/vm/compiler.cc

@@ -1569,15 +1569,16 @@ void BackgroundCompiler::Stop(BackgroundCompiler* task) {
 }
 
 
-void BackgroundCompiler::EnsureInit(Isolate* isolate) {
+void BackgroundCompiler::EnsureInit(Thread* thread) {
   bool start_task = false;
+  Isolate* isolate = thread->isolate();
   {
     MutexLocker ml(isolate->mutex());
     if (isolate->background_compiler() == NULL) {
       BackgroundCompiler* task = new BackgroundCompiler(isolate);
       isolate->set_background_compiler(task);
       isolate->set_background_compilation_queue(GrowableObjectArray::Handle(
-          isolate->current_zone(), GrowableObjectArray::New()));
+          thread->zone(), GrowableObjectArray::New()));
       start_task = true;
     }
   }

runtime/vm/compiler.h

@@ -106,7 +106,7 @@ class Compiler : public AllStatic {
 // isolate.
 class BackgroundCompiler : public ThreadPool::Task {
  public:
-  static void EnsureInit(Isolate* isolate);
+  static void EnsureInit(Thread* thread);
 
   static void Stop(BackgroundCompiler* task);
 

runtime/vm/dart_api_impl.cc

@@ -4966,17 +4966,18 @@ DART_EXPORT void Dart_SetWeakHandleReturnValue(Dart_NativeArguments args,
 
 
 // --- Environment ---
-RawString* Api::CallEnvironmentCallback(Isolate* isolate, const String& name) {
+RawString* Api::CallEnvironmentCallback(Thread* thread, const String& name) {
+  Isolate* isolate = thread->isolate();
   Scope api_scope(isolate);
   Dart_EnvironmentCallback callback = isolate->environment_callback();
-  String& result = String::Handle(isolate->current_zone());
+  String& result = String::Handle(thread->zone());
   if (callback != NULL) {
     Dart_Handle response = callback(Api::NewHandle(isolate, name.raw()));
     if (::Dart_IsString(response)) {
       result ^= Api::UnwrapHandle(response);
     } else if (::Dart_IsError(response)) {
-      const Object& error =
+      const Object& error = Object::Handle(
-          Object::Handle(isolate->current_zone(), Api::UnwrapHandle(response));
+          thread->zone(), Api::UnwrapHandle(response));
       Exceptions::ThrowArgumentError(
           String::Handle(String::New(Error::Cast(error).ToErrorCString())));
     } else if (!::Dart_IsNull(response)) {
@@ -5052,7 +5053,7 @@ DART_EXPORT Dart_Handle Dart_SetLibraryTagHandler(
 // NOTE: Need to pass 'result' as a parameter here in order to avoid
 // warning: variable 'result' might be clobbered by 'longjmp' or 'vfork'
 // which shows up because of the use of setjmp.
-static void CompileSource(Isolate* isolate,
+static void CompileSource(Thread* thread,
                           const Library& lib,
                           const Script& script,
                           Dart_Handle* result) {
@@ -5061,13 +5062,13 @@ static void CompileSource(Isolate* isolate,
   if (update_lib_status) {
     lib.SetLoadInProgress();
   }
-  ASSERT(isolate != NULL);
+  ASSERT(thread != NULL);
   const Error& error =
-      Error::Handle(isolate->current_zone(), Compiler::Compile(lib, script));
+      Error::Handle(thread->zone(), Compiler::Compile(lib, script));
   if (error.IsNull()) {
-    *result = Api::NewHandle(isolate, lib.raw());
+    *result = Api::NewHandle(thread->isolate(), lib.raw());
   } else {
-    *result = Api::NewHandle(isolate, error.raw());
+    *result = Api::NewHandle(thread->isolate(), error.raw());
     // Compilation errors are not Dart instances, so just mark the library
     // as having failed to load without providing an error instance.
     lib.SetLoadError(Object::null_instance());
@@ -5116,7 +5117,7 @@ DART_EXPORT Dart_Handle Dart_LoadScript(Dart_Handle url,
       Script::New(url_str, source_str, RawScript::kScriptTag));
   script.SetLocationOffset(line_offset, column_offset);
   Dart_Handle result;
-  CompileSource(I, library, script, &result);
+  CompileSource(T, library, script, &result);
   return result;
 }
 
@@ -5361,7 +5362,7 @@ DART_EXPORT Dart_Handle Dart_LoadLibrary(Dart_Handle url,
       Script::New(url_str, source_str, RawScript::kLibraryTag));
   script.SetLocationOffset(line_offset, column_offset);
   Dart_Handle result;
-  CompileSource(I, library, script, &result);
+  CompileSource(T, library, script, &result);
   // Propagate the error out right now.
   if (::Dart_IsError(result)) {
     return result;
@@ -5456,7 +5457,7 @@ DART_EXPORT Dart_Handle Dart_LoadSource(Dart_Handle library,
       Script::New(url_str, source_str, RawScript::kSourceTag));
   script.SetLocationOffset(line_offset, column_offset);
   Dart_Handle result;
-  CompileSource(I, lib, script, &result);
+  CompileSource(T, lib, script, &result);
   return result;
 }
 
@@ -5485,7 +5486,7 @@ DART_EXPORT Dart_Handle Dart_LibraryLoadPatch(Dart_Handle library,
   const Script& script = Script::Handle(Z,
       Script::New(url_str, source_str, RawScript::kPatchTag));
   Dart_Handle result;
-  CompileSource(I, lib, script, &result);
+  CompileSource(T, lib, script, &result);
   return result;
 }
 

runtime/vm/dart_api_impl.h

@@ -269,7 +269,7 @@ class Api : AllStatic {
   static void SetWeakHandleReturnValue(NativeArguments* args,
                                        Dart_WeakPersistentHandle retval);
 
-  static RawString* CallEnvironmentCallback(Isolate* isolate,
+  static RawString* CallEnvironmentCallback(Thread* thread,
                                             const String& name);
 
  private:

runtime/vm/debugger.cc

@@ -2402,10 +2402,10 @@ void Debugger::CollectLibraryFields(const GrowableObjectArray& field_list,
                                     const String& prefix,
                                     bool include_private_fields) {
   DictionaryIterator it(lib);
-  Object& entry = Object::Handle(isolate_->current_zone());
+  Object& entry = Object::Handle(zone());
   Field& field = Field::Handle(zone());
   String& field_name = String::Handle(zone());
-  PassiveObject& field_value = PassiveObject::Handle(isolate_->current_zone());
+  PassiveObject& field_value = PassiveObject::Handle(zone());
   while (it.HasNext()) {
     entry = it.GetNext();
     if (entry.IsField()) {

runtime/vm/debugger.h

@@ -650,7 +650,10 @@ class Debugger {
 
   void HandleSteppingRequest(DebuggerStackTrace* stack_trace);
 
-  Zone* zone() const { return isolate_->current_zone(); }
+  Zone* zone() const {
+    ASSERT(isolate_->MutatorThreadIsCurrentThread());
+    return isolate_->current_zone();
+  }
 
   Isolate* isolate_;
   Dart_Port isolate_id_;  // A unique ID for the isolate in the debugger.

runtime/vm/isolate.cc

@@ -217,7 +217,7 @@ const char* IsolateMessageHandler::name() const {
 // [ OOB dispatch, Isolate library dispatch, <message specific data> ]
 RawError* IsolateMessageHandler::HandleLibMessage(const Array& message) {
   if (message.Length() < 2) return Error::null();
-  Zone* zone = I->current_zone();
+  Zone* zone = T->zone();
   const Object& type = Object::Handle(zone, message.At(1));
   if (!type.IsSmi()) return Error::null();
   const intptr_t msg_type = Smi::Cast(type).Value();
@@ -640,10 +640,10 @@ MessageHandler::MessageStatus IsolateMessageHandler::ProcessUnhandledException(
   }
 
   // Generate the error and stacktrace strings for the error message.
-  String& exc_str = String::Handle(I->current_zone());
+  String& exc_str = String::Handle(T->zone());
-  String& stacktrace_str = String::Handle(I->current_zone());
+  String& stacktrace_str = String::Handle(T->zone());
   if (result.IsUnhandledException()) {
-    Zone* zone = I->current_zone();
+    Zone* zone = T->zone();
     const UnhandledException& uhe = UnhandledException::Cast(result);
     const Instance& exception = Instance::Handle(zone, uhe.exception());
     Object& tmp = Object::Handle(zone);
@@ -1887,8 +1887,7 @@ void Isolate::PrintJSON(JSONStream* stream, bool ref) {
     vm_tag_counters()->PrintToJSONObject(&tagCounters);
   }
   if (object_store()->sticky_error() != Object::null()) {
-    Error& error = Error::Handle(current_zone(),
+    Error& error = Error::Handle(object_store()->sticky_error());
-        object_store()->sticky_error());
     ASSERT(!error.IsNull());
     jsobj.AddProperty("error", error, false);
   }

runtime/vm/native_api_impl.cc

@@ -69,14 +69,13 @@ DART_EXPORT bool Dart_CloseNativePort(Dart_Port native_port_id) {
 
 // --- Verification tools ---
 
-static void CompileAll(Isolate* isolate, Dart_Handle* result) {
+static void CompileAll(Thread* thread, Dart_Handle* result) {
-  ASSERT(isolate != NULL);
+  ASSERT(thread != NULL);
-  const Error& error =
+  const Error& error = Error::Handle(thread->zone(), Library::CompileAll());
-      Error::Handle(isolate->current_zone(), Library::CompileAll());
   if (error.IsNull()) {
     *result = Api::Success();
   } else {
-    *result = Api::NewHandle(isolate, error.raw());
+    *result = Api::NewHandle(thread->isolate(), error.raw());
   }
 }
 
@@ -88,7 +87,7 @@ DART_EXPORT Dart_Handle Dart_CompileAll() {
     return result;
   }
   CHECK_CALLBACK_STATE(T);
-  CompileAll(I, &result);
+  CompileAll(T, &result);
   return result;
 }
 

runtime/vm/object.cc

@@ -17641,7 +17641,7 @@ bool Bigint::CheckAndCanonicalizeFields(const char** error_str) const {
     ASSERT(!digits_.IsNull());
     set_digits(digits_);
   } else {
-    ASSERT(digits() == TypedData::EmptyUint32Array(Isolate::Current()));
+    ASSERT(digits() == TypedData::EmptyUint32Array(Thread::Current()));
   }
   return true;
 }
@@ -17663,7 +17663,7 @@ RawBigint* Bigint::New(Heap::Space space) {
   result.SetNeg(false);
   result.SetUsed(0);
   result.set_digits(
-      TypedData::Handle(zone, TypedData::EmptyUint32Array(isolate)));
+      TypedData::Handle(zone, TypedData::EmptyUint32Array(thread)));
   return result.raw();
 }
 
@@ -17697,7 +17697,7 @@ RawBigint* Bigint::New(bool neg, intptr_t used, const TypedData& digits,
   } else {
     neg = false;
     result.set_digits(
-        TypedData::Handle(zone, TypedData::EmptyUint32Array(isolate)));
+        TypedData::Handle(zone, TypedData::EmptyUint32Array(thread)));
   }
   result.SetNeg(neg);
   result.SetUsed(used);
@@ -20920,14 +20920,16 @@ RawTypedData* TypedData::New(intptr_t class_id,
 }
 
 
-RawTypedData* TypedData::EmptyUint32Array(Isolate* isolate) {
+RawTypedData* TypedData::EmptyUint32Array(Thread* thread) {
+  ASSERT(thread != NULL);
+  Isolate* isolate = thread->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->current_zone(),
+  const TypedData& array = TypedData::Handle(thread->zone(),
       TypedData::New(kTypedDataUint32ArrayCid, 0, Heap::kOld));
   isolate->object_store()->set_empty_uint32_array(array);
   return array.raw();
@@ -21590,10 +21592,11 @@ void UserTag::MakeActive() const {
 
 
 RawUserTag* UserTag::New(const String& label, Heap::Space space) {
-  Isolate* isolate = Isolate::Current();
+  Thread* thread = Thread::Current();
+  Isolate* isolate = thread->isolate();
   ASSERT(isolate->tag_table() != GrowableObjectArray::null());
   // Canonicalize by name.
-  UserTag& result = UserTag::Handle(FindTagInIsolate(isolate, label));
+  UserTag& result = UserTag::Handle(FindTagInIsolate(thread, label));
   if (!result.IsNull()) {
     // Tag already exists, return existing instance.
     return result.raw();
@@ -21615,7 +21618,7 @@ RawUserTag* UserTag::New(const String& label, Heap::Space space) {
     result ^= raw;
   }
   result.set_label(label);
-  AddTagToIsolate(isolate, result);
+  AddTagToIsolate(thread, result);
   return result.raw();
 }
 
@@ -21638,12 +21641,14 @@ RawUserTag* UserTag::DefaultTag() {
 }
 
 
-RawUserTag* UserTag::FindTagInIsolate(Isolate* isolate, const String& label) {
+RawUserTag* UserTag::FindTagInIsolate(Thread* thread, const String& label) {
+  Isolate* isolate = thread->isolate();
+  Zone* zone = thread->zone();
   ASSERT(isolate->tag_table() != GrowableObjectArray::null());
   const GrowableObjectArray& tag_table = GrowableObjectArray::Handle(
-      isolate->current_zone(), isolate->tag_table());
+      zone, isolate->tag_table());
-  UserTag& other = UserTag::Handle(isolate->current_zone());
+  UserTag& other = UserTag::Handle(zone);
-  String& tag_label = String::Handle(isolate->current_zone());
+  String& tag_label = String::Handle(zone);
   for (intptr_t i = 0; i < tag_table.Length(); i++) {
     other ^= tag_table.At(i);
     ASSERT(!other.IsNull());
@@ -21657,10 +21662,12 @@ RawUserTag* UserTag::FindTagInIsolate(Isolate* isolate, const String& label) {
 }
 
 
-void UserTag::AddTagToIsolate(Isolate* isolate, const UserTag& tag) {
+void UserTag::AddTagToIsolate(Thread* thread, const UserTag& tag) {
+  Isolate* isolate = thread->isolate();
+  Zone* zone = thread->zone();
   ASSERT(isolate->tag_table() != GrowableObjectArray::null());
   const GrowableObjectArray& tag_table = GrowableObjectArray::Handle(
-      isolate->current_zone(), isolate->tag_table());
+      zone, isolate->tag_table());
   ASSERT(!TagTableIsFull(isolate));
 #if defined(DEBUG)
   // Verify that no existing tag has the same tag id.

runtime/vm/object.h

@@ -7208,7 +7208,7 @@ class TypedData : public Instance {
     return RawObject::IsTypedDataClassId(cid);
   }
 
-  static RawTypedData* EmptyUint32Array(Isolate* isolate);
+  static RawTypedData* EmptyUint32Array(Thread* thread);
 
  protected:
   void SetLength(intptr_t value) const {
@@ -7978,8 +7978,8 @@ class UserTag : public Instance {
   static RawUserTag* FindTagById(uword tag_id);
 
  private:
-  static RawUserTag* FindTagInIsolate(Isolate* isolate, const String& label);
+  static RawUserTag* FindTagInIsolate(Thread* thread, const String& label);
-  static void AddTagToIsolate(Isolate* isolate, const UserTag& tag);
+  static void AddTagToIsolate(Thread* thread, const UserTag& tag);
 
   void set_label(const String& tag_label) const {
     StorePointer(&raw_ptr()->label_, tag_label.raw());

runtime/vm/service.cc

@@ -1101,7 +1101,7 @@ static bool ContainsNonInstance(const Object& obj) {
 }
 
 
-static RawObject* LookupObjectId(Isolate* isolate,
+static RawObject* LookupObjectId(Thread* thread,
                                  const char* arg,
                                  ObjectIdRing::LookupResult* kind) {
   *kind = ObjectIdRing::kValid;
@@ -1113,7 +1113,7 @@ static RawObject* LookupObjectId(Isolate* isolate,
       *kind = ObjectIdRing::kInvalid;
       return Object::null();
     }
-    const Integer& obj = Integer::Handle(isolate->current_zone(),
+    const Integer& obj = Integer::Handle(thread->zone(),
         Smi::New(static_cast<intptr_t>(value)));
     return obj.raw();
   } else if (strcmp(arg, "bool-true") == 0) {
@@ -1124,7 +1124,7 @@ static RawObject* LookupObjectId(Isolate* isolate,
     return Object::null();
   }
 
-  ObjectIdRing* ring = isolate->object_id_ring();
+  ObjectIdRing* ring = thread->isolate()->object_id_ring();
   ASSERT(ring != NULL);
   intptr_t id = -1;
   if (!GetIntegerId(arg, &id)) {
@@ -1185,19 +1185,21 @@ static RawObject* LookupHeapObjectLibraries(Isolate* isolate,
   return Object::sentinel().raw();
 }
 
-static RawObject* LookupHeapObjectClasses(Isolate* isolate,
+static RawObject* LookupHeapObjectClasses(Thread* thread,
                                           char** parts, int num_parts) {
   // Class ids look like: "classes/17"
   if (num_parts < 2) {
     return Object::sentinel().raw();
   }
+  Isolate* isolate = thread->isolate();
+  Zone* zone = thread->zone();
   ClassTable* table = isolate->class_table();
   intptr_t id;
   if (!GetIntegerId(parts[1], &id) ||
       !table->IsValidIndex(id)) {
     return Object::sentinel().raw();
   }
-  Class& cls = Class::Handle(table->At(id));
+  Class& cls = Class::Handle(zone, table->At(id));
   if (num_parts == 2) {
     return cls.raw();
   }
@@ -1210,7 +1212,7 @@ static RawObject* LookupHeapObjectClasses(Isolate* isolate,
     if (!GetIntegerId(parts[3], &id)) {
       return Object::sentinel().raw();
     }
-    Function& func = Function::Handle();
+    Function& func = Function::Handle(zone);
     func ^= cls.ClosureFunctionFromIndex(id);
     if (func.IsNull()) {
       return Object::sentinel().raw();
@@ -1226,7 +1228,7 @@ static RawObject* LookupHeapObjectClasses(Isolate* isolate,
     if (!GetIntegerId(parts[3], &id)) {
       return Object::sentinel().raw();
     }
-    Field& field = Field::Handle(cls.FieldFromIndex(id));
+    Field& field = Field::Handle(zone, cls.FieldFromIndex(id));
     if (field.IsNull()) {
       return Object::sentinel().raw();
     }
@@ -1238,13 +1240,12 @@ static RawObject* LookupHeapObjectClasses(Isolate* isolate,
       return Object::sentinel().raw();
     }
     const char* encoded_id = parts[3];
-    String& id = String::Handle(isolate->current_zone(),
+    String& id = String::Handle(zone, String::New(encoded_id));
-        String::New(encoded_id));
     id = String::DecodeIRI(id);
     if (id.IsNull()) {
       return Object::sentinel().raw();
     }
-    Function& func = Function::Handle(cls.LookupFunction(id));
+    Function& func = Function::Handle(zone, cls.LookupFunction(id));
     if (func.IsNull()) {
       return Object::sentinel().raw();
     }
@@ -1259,7 +1260,7 @@ static RawObject* LookupHeapObjectClasses(Isolate* isolate,
     if (!GetIntegerId(parts[3], &id)) {
       return Object::sentinel().raw();
     }
-    Function& func = Function::Handle();
+    Function& func = Function::Handle(zone);
     func ^= cls.ImplicitClosureFunctionFromIndex(id);
     if (func.IsNull()) {
       return Object::sentinel().raw();
@@ -1275,7 +1276,7 @@ static RawObject* LookupHeapObjectClasses(Isolate* isolate,
     if (!GetIntegerId(parts[3], &id)) {
       return Object::sentinel().raw();
     }
-    Function& func = Function::Handle();
+    Function& func = Function::Handle(zone);
     func ^= cls.InvocationDispatcherFunctionFromIndex(id);
     if (func.IsNull()) {
       return Object::sentinel().raw();
@@ -1291,7 +1292,7 @@ static RawObject* LookupHeapObjectClasses(Isolate* isolate,
     if (!GetIntegerId(parts[3], &id)) {
       return Object::sentinel().raw();
     }
-    Type& type = Type::Handle();
+    Type& type = Type::Handle(zone);
     type ^= cls.CanonicalTypeFromIndex(id);
     if (type.IsNull()) {
       return Object::sentinel().raw();
@@ -1304,8 +1305,9 @@ static RawObject* LookupHeapObjectClasses(Isolate* isolate,
 }
 
 
-static RawObject* LookupHeapObjectTypeArguments(Isolate* isolate,
+static RawObject* LookupHeapObjectTypeArguments(Thread* thread,
-                                          char** parts, int num_parts) {
+                                                char** parts, int num_parts) {
+  Isolate* isolate = thread->isolate();
   // TypeArguments ids look like: "typearguments/17"
   if (num_parts < 2) {
     return Object::sentinel().raw();
@@ -1315,7 +1317,8 @@ static RawObject* LookupHeapObjectTypeArguments(Isolate* isolate,
     return Object::sentinel().raw();
   }
   ObjectStore* object_store = isolate->object_store();
-  const Array& table = Array::Handle(object_store->canonical_type_arguments());
+  const Array& table = Array::Handle(thread->zone(),
+                                     object_store->canonical_type_arguments());
   ASSERT(table.Length() > 0);
   const intptr_t table_size = table.Length() - 1;
   if ((id < 0) || (id >= table_size) || (table.At(id) == Object::null())) {
@@ -1399,7 +1402,8 @@ static RawObject* LookupHeapObjectMessage(Isolate* isolate,
 static RawObject* LookupHeapObject(Isolate* isolate,
                                    const char* id_original,
                                    ObjectIdRing::LookupResult* result) {
-  char* id = Thread::Current()->zone()->MakeCopyOfString(id_original);
+  Thread* thread = Thread::Current();
+  char* id = thread->zone()->MakeCopyOfString(id_original);
 
   // Parse the id by splitting at each '/'.
   const int MAX_PARTS = 8;
@@ -1429,9 +1433,9 @@ static RawObject* LookupHeapObject(Isolate* isolate,
 
   if (strcmp(parts[0], "objects") == 0) {
     // Object ids look like "objects/1123"
-    Object& obj = Object::Handle(isolate->current_zone());
+    Object& obj = Object::Handle(thread->zone());
     ObjectIdRing::LookupResult lookup_result;
-    obj = LookupObjectId(isolate, parts[1], &lookup_result);
+    obj = LookupObjectId(thread, parts[1], &lookup_result);
     if (lookup_result != ObjectIdRing::kValid) {
       if (result != NULL) {
         *result = lookup_result;
@@ -1443,9 +1447,9 @@ static RawObject* LookupHeapObject(Isolate* isolate,
   } else if (strcmp(parts[0], "libraries") == 0) {
     return LookupHeapObjectLibraries(isolate, parts, num_parts);
   } else if (strcmp(parts[0], "classes") == 0) {
-    return LookupHeapObjectClasses(isolate, parts, num_parts);
+    return LookupHeapObjectClasses(thread, parts, num_parts);
   } else if (strcmp(parts[0], "typearguments") == 0) {
-    return LookupHeapObjectTypeArguments(isolate, parts, num_parts);
+    return LookupHeapObjectTypeArguments(thread, parts, num_parts);
   } else if (strcmp(parts[0], "code") == 0) {
     return LookupHeapObjectCode(isolate, parts, num_parts);
   } else if (strcmp(parts[0], "messages") == 0) {
@@ -1779,11 +1783,11 @@ static bool Evaluate(Isolate* isolate, JSONStream* js) {
     PrintMissingParamError(js, "expression");
     return true;
   }
-  const String& expr_str =
+  Zone* zone = Thread::Current()->zone();
-      String::Handle(isolate->current_zone(), String::New(expr));
+  const String& expr_str = String::Handle(zone, String::New(expr));
   ObjectIdRing::LookupResult lookup_result;
-  Object& obj = Object::Handle(LookupHeapObject(isolate, target_id,
+  Object& obj = Object::Handle(zone, LookupHeapObject(isolate, target_id,
-                                                &lookup_result));
+                                                      &lookup_result));
   if (obj.raw() == Object::sentinel().raw()) {
     if (lookup_result == ObjectIdRing::kCollected) {
       PrintSentinel(js, kCollectedSentinel);
@@ -1796,29 +1800,27 @@ static bool Evaluate(Isolate* isolate, JSONStream* js) {
   }
   if (obj.IsLibrary()) {
     const Library& lib = Library::Cast(obj);
-    const Object& result = Object::Handle(lib.Evaluate(expr_str,
+    const Object& result = Object::Handle(zone,
-                                                       Array::empty_array(),
+        lib.Evaluate(expr_str, Array::empty_array(), Array::empty_array()));
-                                                       Array::empty_array()));
     result.PrintJSON(js, true);
     return true;
   }
   if (obj.IsClass()) {
     const Class& cls = Class::Cast(obj);
-    const Object& result = Object::Handle(cls.Evaluate(expr_str,
+    const Object& result = Object::Handle(zone,
-                                                       Array::empty_array(),
+        cls.Evaluate(expr_str, Array::empty_array(), Array::empty_array()));
-                                                       Array::empty_array()));
     result.PrintJSON(js, true);
     return true;
   }
   if ((obj.IsInstance() || obj.IsNull()) &&
       !ContainsNonInstance(obj)) {
     // We don't use Instance::Cast here because it doesn't allow null.
-    Instance& instance = Instance::Handle(isolate->current_zone());
+    Instance& instance = Instance::Handle(zone);
     instance ^= obj.raw();
     const Object& result =
-        Object::Handle(instance.Evaluate(expr_str,
+        Object::Handle(zone, instance.Evaluate(expr_str,
-                                         Array::empty_array(),
+                                               Array::empty_array(),
-                                         Array::empty_array()));
+                                               Array::empty_array()));
     result.PrintJSON(js, true);
     return true;
   }
@@ -1852,11 +1854,11 @@ static bool EvaluateInFrame(Isolate* isolate, JSONStream* js) {
   }
   ActivationFrame* frame = stack->FrameAt(framePos);
 
+  Zone* zone = Thread::Current()->zone();
   const char* expr = js->LookupParam("expression");
-  const String& expr_str = String::Handle(isolate->current_zone(),
+  const String& expr_str = String::Handle(zone, String::New(expr));
-      String::New(expr));
 
-  const Object& result = Object::Handle(frame->Evaluate(expr_str));
+  const Object& result = Object::Handle(zone, frame->Evaluate(expr_str));
   result.PrintJSON(js, true);
   return true;
 }

runtime/vm/snapshot.cc

@@ -1729,15 +1729,15 @@ bool SnapshotWriter::HandleVMIsolateObject(RawObject* rawobj) {
 // objects and their accompanying token streams.
 class ScriptVisitor : public ObjectVisitor {
  public:
-  explicit ScriptVisitor(Isolate* isolate) :
+  explicit ScriptVisitor(Thread* thread) :
-      ObjectVisitor(isolate),
+      ObjectVisitor(thread->isolate()),
-      objHandle_(Object::Handle(isolate->current_zone())),
+      objHandle_(Object::Handle(thread->zone())),
       count_(0),
       scripts_(NULL) {}
 
-  ScriptVisitor(Isolate* isolate, const Array* scripts) :
+  ScriptVisitor(Thread* thread, const Array* scripts) :
-      ObjectVisitor(isolate),
+      ObjectVisitor(thread->isolate()),
-      objHandle_(Object::Handle(isolate->current_zone())),
+      objHandle_(Object::Handle(thread->zone())),
       count_(0),
       scripts_(scripts) {}
 
@@ -1797,11 +1797,11 @@ FullSnapshotWriter::FullSnapshotWriter(uint8_t** vm_isolate_snapshot_buffer,
   // into an array so that we can write it out as part of the VM isolate
   // snapshot. We first count the number of script objects, allocate an array
   // and then fill it up with the script objects.
-  ScriptVisitor scripts_counter(isolate());
+  ScriptVisitor scripts_counter(thread());
   heap()->IterateOldObjects(&scripts_counter);
   intptr_t count = scripts_counter.count();
   scripts_ = Array::New(count, Heap::kOld);
-  ScriptVisitor script_visitor(isolate(), &scripts_);
+  ScriptVisitor script_visitor(thread(), &scripts_);
   heap()->IterateOldObjects(&script_visitor);
 
   // Stash the symbol table away for writing and reading into the vm isolate,