[Interpreter] Add ClassOf intrinsic.

src/code-stub-assembler.cc

 // Copyright 2016 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.
 
 #include "src/code-stub-assembler.h"
 #include "src/code-factory.h"
 #include "src/frames-inl.h"
 #include "src/frames.h"
 #include "src/ic/stub-cache.h"
 
@@ skipping 549 matching lines @@
 Node* CodeStubAssembler::LoadMapInobjectProperties(Node* map) {
   // See Map::GetInObjectProperties() for details.
   STATIC_ASSERT(LAST_JS_OBJECT_TYPE == LAST_TYPE);
   Assert(Int32GreaterThanOrEqual(LoadMapInstanceType(map),
                                  Int32Constant(FIRST_JS_OBJECT_TYPE)));
   return LoadObjectField(
       map, Map::kInObjectPropertiesOrConstructorFunctionIndexOffset,
       MachineType::Uint8());
 }
 
+Node* CodeStubAssembler::LoadMapConstructor(Node* map) {
+  Variable result(this, MachineRepresentation::kTagged);
+  result.Bind(LoadObjectField(map, Map::kConstructorOrBackPointerOffset));
+
+  Label done(this), loop(this, &result);
+  Goto(&loop);
+  Bind(&loop);
+  {
+    GotoIf(WordIsSmi(result.value()), &done);
+    Node* is_map_type =
+        Word32Equal(LoadInstanceType(result.value()), Int32Constant(MAP_TYPE));
+    GotoUnless(is_map_type, &done);
+    result.Bind(
+        LoadObjectField(result.value(), Map::kConstructorOrBackPointerOffset));
+    Goto(&loop);
+  }
+  Bind(&done);
+  return result.value();
+}
+
 Node* CodeStubAssembler::LoadNameHashField(Node* name) {
   return LoadObjectField(name, Name::kHashFieldOffset, MachineType::Uint32());
 }
 
 Node* CodeStubAssembler::LoadNameHash(Node* name, Label* if_hash_not_computed) {
   Node* hash_field = LoadNameHashField(name);
   if (if_hash_not_computed != nullptr) {
     GotoIf(WordEqual(
                Word32And(hash_field, Int32Constant(Name::kHashNotComputedMask)),
                Int32Constant(0)),
@@ skipping 2200 matching lines @@
   }
   Bind(&miss);
   {
     TailCallRuntime(Runtime::kLoadGlobalIC_Miss, p->context, p->slot,
                     p->vector);
   }
 }
 
 }  // namespace internal
 }  // namespace v8