[Interpreter] Add support for for..in.

src/compiler/interpreter-assembler.h

Index: src/compiler/interpreter-assembler.h
diff --git a/src/compiler/interpreter-assembler.h b/src/compiler/interpreter-assembler.h
index b546fb21f0526f1211e90ed927182e6632351ba9..dc6cd4504a82ffd2e75185e96618f467ff713686 100644
--- a/src/compiler/interpreter-assembler.h
+++ b/src/compiler/interpreter-assembler.h
@@ -79,6 +79,8 @@ class InterpreterAssembler {
   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);
@@ -92,6 +94,9 @@ class InterpreterAssembler {
   // 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);