[deoptimizer] Add support for materializing Generator objects.

This adds support for materializing objects of {JSGeneratorObject} type
during deoptimization. Cases where soft-deopts remove any escaping use
of the implicit generator object can cause it to be escape analyzed.

R=jarin@chromium.org
TEST=mjsunit/regress/regress-crbug-732169
BUG=chromium:732169

Change-Id: I2ec10b2a509a4f37a456a8ca2fd74b8de2fb55be
Reviewed-on: https://chromium-review.googlesource.com/530847Reviewed-by: Georg Neis <neis@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#45849}

src/deoptimizer.cc

@@ -4442,6 +4442,30 @@ Handle<Object> TranslatedState::MaterializeCapturedObjectAt(
       object->set_bound_arguments(FixedArray::cast(*bound_arguments));
       return object;
     }
+    case JS_GENERATOR_OBJECT_TYPE: {
+      Handle<JSGeneratorObject> object = Handle<JSGeneratorObject>::cast(
+          isolate_->factory()->NewJSObjectFromMap(map, NOT_TENURED));
+      slot->value_ = object;
+      Handle<Object> properties = materializer.FieldAt(value_index);
+      Handle<Object> elements = materializer.FieldAt(value_index);
+      Handle<Object> function = materializer.FieldAt(value_index);
+      Handle<Object> context = materializer.FieldAt(value_index);
+      Handle<Object> receiver = materializer.FieldAt(value_index);
+      Handle<Object> input_or_debug_pos = materializer.FieldAt(value_index);
+      Handle<Object> resume_mode = materializer.FieldAt(value_index);
+      Handle<Object> continuation_offset = materializer.FieldAt(value_index);
+      Handle<Object> register_file = materializer.FieldAt(value_index);
+      object->set_properties(FixedArray::cast(*properties));
+      object->set_elements(FixedArrayBase::cast(*elements));
+      object->set_function(JSFunction::cast(*function));
+      object->set_context(Context::cast(*context));
+      object->set_receiver(*receiver);
+      object->set_input_or_debug_pos(*input_or_debug_pos);
+      object->set_resume_mode(Smi::cast(*resume_mode)->value());
+      object->set_continuation(Smi::cast(*continuation_offset)->value());
+      object->set_register_file(FixedArray::cast(*register_file));
+      return object;
+    }
     case CONS_STRING_TYPE: {
       Handle<ConsString> object = Handle<ConsString>::cast(
           isolate_->factory()
@@ -4544,7 +4568,6 @@ Handle<Object> TranslatedState::MaterializeCapturedObjectAt(
     case JS_MESSAGE_OBJECT_TYPE:
     case JS_DATE_TYPE:
     case JS_CONTEXT_EXTENSION_OBJECT_TYPE:
-    case JS_GENERATOR_OBJECT_TYPE:
     case JS_ASYNC_GENERATOR_OBJECT_TYPE:
     case JS_MODULE_NAMESPACE_TYPE:
     case JS_ARRAY_BUFFER_TYPE:

test/mjsunit/regress/regress-crbug-732169.js

+// Copyright 2017 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --allow-natives-syntax
+
+function* f([x]) { yield x }
+// No warm-up of {f} to trigger soft deopt.
+%OptimizeFunctionOnNextCall(f);
+var gen = f([23]);
+
+assertEquals("[object Generator]", gen.toString());
+assertEquals({ done:false, value:23 }, gen.next());
+assertEquals({ done:true, value:undefined }, gen.next());