[Interpreter] Add support for for..in.

src/compiler/interpreter-assembler.h

 // Copyright 2015 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.
 
 #ifndef V8_COMPILER_INTERPRETER_ASSEMBLER_H_
 #define V8_COMPILER_INTERPRETER_ASSEMBLER_H_
 
 // Clients of this interface shouldn't depend on lots of compiler internals.
 // Do not include anything from src/compiler here!
 #include "src/allocation.h"
@@ skipping 61 matching lines @@
   // Returns the location in memory of the register |reg_index| in the
   // interpreter register file.
   Node* RegisterLocation(Node* reg_index);
 
   // Constants.
   Node* Int32Constant(int value);
   Node* IntPtrConstant(intptr_t value);
   Node* NumberConstant(double value);
   Node* HeapConstant(Handle<HeapObject> object);
   Node* BooleanConstant(bool value);
+  Node* NullConstant();
+  Node* UndefinedConstant();

[rmcilroy, 2015/10/28 13:46:22]

nit - you can just use HeapConstant(factory()->undefined_value()) for these to
avoid the extra functions. I don't really mind though (although would we used
one or the other approach consistently in interpreter.cc).

[oth, 2015/10/28 22:50:40]

Okay, used the more verbose form.

 
   // Tag and untag Smi values.
   Node* SmiTag(Node* value);
   Node* SmiUntag(Node* value);
 
   // Basic arithmetic operations.
   Node* IntPtrAdd(Node* a, Node* b);
   Node* IntPtrSub(Node* a, Node* b);
   Node* WordShl(Node* value, int shift);
 
   // Load constant at |index| in the constant pool.
   Node* LoadConstantPoolEntry(Node* index);
 
+  // Load an element from a fixed array on the heap.
+  Node* LoadFixedArrayElement(Node* fixed_array, int index);
+
   // Load a field from an object on the heap.
   Node* LoadObjectField(Node* object, int offset);
 
   // Load |slot_index| from |context|.
   Node* LoadContextSlot(Node* context, int slot_index);
   Node* LoadContextSlot(Node* context, Node* slot_index);
   // Stores |value| into |slot_index| of |context|.
   Node* StoreContextSlot(Node* context, Node* slot_index, Node* value);
 
   // Load the TypeFeedbackVector for the current function.
@@ skipping 103 matching lines @@
   bool code_generated_;
 
   DISALLOW_COPY_AND_ASSIGN(InterpreterAssembler);
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_INTERPRETER_ASSEMBLER_H_