From 74c0cdbf762ff42f3d39c21329e468c451d7c564 Mon Sep 17 00:00:00 2001
From: verwaest <verwaest@chromium.org>
Date: Mon, 23 Feb 2015 10:25:38 -0800
Subject: [PATCH] Prototype objects never share their map, and hence cannot be
 in deprecated state.

Review URL: https://codereview.chromium.org/955433002

Cr-Commit-Position: refs/heads/master@{#26802}
---
 src/ic/handler-compiler.cc |  2 +-
 src/objects.cc             | 34 ++++++++++------------------------
 src/objects.h              |  7 ++-----
 3 files changed, 13 insertions(+), 30 deletions(-)

diff --git a/src/ic/handler-compiler.cc b/src/ic/handler-compiler.cc
index 4fd61b4f41..15dc941503 100644
--- a/src/ic/handler-compiler.cc
+++ b/src/ic/handler-compiler.cc
@@ -74,7 +74,7 @@ Handle<Code> PropertyHandlerCompiler::GetCode(Code::Kind kind,
                                               Handle<Name> name) {
   Code::Flags flags = Code::ComputeHandlerFlags(kind, type, cache_holder());
   Handle<Code> code = GetCodeWithFlags(flags, name);
-  PROFILE(isolate(), CodeCreateEvent(Logger::STUB_TAG, *code, *name));
+  PROFILE(isolate(), CodeCreateEvent(Logger::HANDLER_TAG, *code, *name));
 #ifdef DEBUG
   code->VerifyEmbeddedObjects();
 #endif
diff --git a/src/objects.cc b/src/objects.cc
index ea4b6644c1..7a3490286a 100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -2931,30 +2931,7 @@ Handle<Map> Map::GeneralizeAllFieldRepresentations(
 
 
 // static
-MaybeHandle<Map> Map::TryUpdate(Handle<Map> map) {
-  Handle<Map> proto_map(map);
-  while (proto_map->prototype()->IsJSObject()) {
-    Handle<JSObject> holder(JSObject::cast(proto_map->prototype()));
-    proto_map = Handle<Map>(holder->map());
-    if (proto_map->is_deprecated() && JSObject::TryMigrateInstance(holder)) {
-      proto_map = Handle<Map>(holder->map());
-    }
-  }
-  return TryUpdateInternal(map);
-}
-
-
-// static
-Handle<Map> Map::Update(Handle<Map> map) {
-  if (!map->is_deprecated()) return map;
-  return ReconfigureProperty(map, -1, kData, NONE, Representation::None(),
-                             HeapType::None(map->GetIsolate()),
-                             ALLOW_IN_DESCRIPTOR);
-}
-
-
-// static
-MaybeHandle<Map> Map::TryUpdateInternal(Handle<Map> old_map) {
+MaybeHandle<Map> Map::TryUpdate(Handle<Map> old_map) {
   DisallowHeapAllocation no_allocation;
   DisallowDeoptimization no_deoptimization(old_map->GetIsolate());
 
@@ -3018,6 +2995,15 @@ MaybeHandle<Map> Map::TryUpdateInternal(Handle<Map> old_map) {
 }
 
 
+// static
+Handle<Map> Map::Update(Handle<Map> map) {
+  if (!map->is_deprecated()) return map;
+  return ReconfigureProperty(map, -1, kData, NONE, Representation::None(),
+                             HeapType::None(map->GetIsolate()),
+                             ALLOW_IN_DESCRIPTOR);
+}
+
+
 MaybeHandle<Object> JSObject::SetPropertyWithInterceptor(LookupIterator* it,
                                                          Handle<Object> value) {
   Handle<Name> name = it->name();
diff --git a/src/objects.h b/src/objects.h
index d4af4a6255..8b6f1e2e62 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -6068,12 +6068,9 @@ class Map: public HeapObject {
   // Returns a non-deprecated version of the input. If the input was not
   // deprecated, it is directly returned. Otherwise, the non-deprecated version
   // is found by re-transitioning from the root of the transition tree using the
-  // descriptor array of the map. Returns NULL if no updated map is found.
-  // This method also applies any pending migrations along the prototype chain.
+  // descriptor array of the map. Returns MaybeHandle<Map>() if no updated map
+  // is found.
   static MaybeHandle<Map> TryUpdate(Handle<Map> map) WARN_UNUSED_RESULT;
-  // Same as above, but does not touch the prototype chain.
-  static MaybeHandle<Map> TryUpdateInternal(Handle<Map> map)
-      WARN_UNUSED_RESULT;
 
   // Returns a non-deprecated version of the input. This method may deprecate
   // existing maps along the way if encodings conflict. Not for use while