[interpreter] Add CreateFunctionContext bytecode

src/interpreter/bytecode-array-builder.cc

 // 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.
 
 #include "src/interpreter/bytecode-array-builder.h"
 
 #include "src/compiler.h"
 #include "src/globals.h"
 #include "src/interpreter/bytecode-array-writer.h"
 #include "src/interpreter/bytecode-dead-code-optimizer.h"
@@ skipping 319 matching lines @@
 }
 
 BytecodeArrayBuilder& BytecodeArrayBuilder::CreateClosure(
     Handle<SharedFunctionInfo> shared_info, int flags) {
   size_t entry = GetConstantPoolEntry(shared_info);
   Output(Bytecode::kCreateClosure, UnsignedOperand(entry),
          UnsignedOperand(flags));
   return *this;
 }
 
+BytecodeArrayBuilder& BytecodeArrayBuilder::CreateFunctionContext(int slots) {
+  Output(Bytecode::kCreateFunctionContext, SignedOperand(slots));

[rmcilroy, 2016/08/03 10:58:14]

Signed? This should always be positive right? Could you make the bytecode take
an unsigned operand (we probably need to add a new type or rename the Idx type).
Feel free to do this in a followup CL and just add a TODO here

[klaasb, 2016/08/03 12:28:16]

Switched to unsigned and Idx in bytecodes.h, added a comment there.

+  return *this;
+}
+
 BytecodeArrayBuilder& BytecodeArrayBuilder::CreateArguments(
     CreateArgumentsType type) {
   // TODO(rmcilroy): Consider passing the type as a bytecode operand rather
   // than having two different bytecodes once we have better support for
   // branches in the InterpreterAssembler.
   Bytecode bytecode = BytecodeForCreateArguments(type);
   Output(bytecode);
   return *this;
 }
 
@@ skipping 606 matching lines @@
       return Bytecode::kTailCall;
     default:
       UNREACHABLE();
   }
   return Bytecode::kIllegal;
 }
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8