[Interpreter] Add support for parameter variables.

src/objects-inl.h

 // Copyright 2012 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.
 //
 // Review notes:
 //
 // - The use of macros in these inline functions may seem superfluous
 // but it is absolutely needed to make sure gcc generates optimal
 // code. gcc is not happy when attempting to inline too deep.
 //
@@ skipping 4040 matching lines @@
   DCHECK(IsAligned(frame_size, static_cast<unsigned>(kPointerSize)));
   WRITE_INT_FIELD(this, kFrameSizeOffset, frame_size);
 }
 
 
 int BytecodeArray::frame_size() const {
   return READ_INT_FIELD(this, kFrameSizeOffset);
 }
 
 
+void BytecodeArray::set_parameter_count(int number_of_parameters) {
+  DCHECK_GE(number_of_parameters, 0);
+  // Parameter count is stored as the size on stack of the parameters to allow
+  // it to be used directly by generated code.
+  WRITE_INT_FIELD(this, kParameterSizeOffset,
+                  (number_of_parameters << kPointerSizeLog2));
+}
+
+
+int BytecodeArray::parameter_count() const {
+  // Parameter count is stored as the size on stack of the parameters to allow
+  // it to be used directly by generated code.
+  return READ_INT_FIELD(this, kParameterSizeOffset) >> kPointerSizeLog2;
+}
+
+
 Address BytecodeArray::GetFirstBytecodeAddress() {
   return reinterpret_cast<Address>(this) - kHeapObjectTag + kHeaderSize;
 }
 
 
 int BytecodeArray::BytecodeArraySize() { return SizeFor(this->length()); }
 
 
 ACCESSORS(FixedTypedArrayBase, base_pointer, Object, kBasePointerOffset)
 
@@ skipping 3787 matching lines @@
 #undef READ_INT64_FIELD
 #undef WRITE_INT64_FIELD
 #undef READ_BYTE_FIELD
 #undef WRITE_BYTE_FIELD
 #undef NOBARRIER_READ_BYTE_FIELD
 #undef NOBARRIER_WRITE_BYTE_FIELD
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_INL_H_