Move builtin JavaScript sources into own directory.

src/code-stubs.js

-// 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.
-
-(function(global, code_stubs) {
-
-"use strict";
-
-code_stubs.StringLengthTFStub = function StringLengthTFStub(call_conv, minor_key) {
-  var stub = function(receiver, name, i, v) {
-    // i and v are dummy parameters mandated by the InterfaceDescriptor,
-    // (LoadWithVectorDescriptor).
-    return %_StringGetLength(%_JSValueGetValue(receiver));
-  }
-  return stub;
-}
-
-code_stubs.StringAddTFStub = function StringAddTFStub(call_conv, minor_key) {
-  var stub = function(left, right) {
-    return %StringAdd(left, right);
-  }
-  return stub;
-}
-
-const kTurboFanICCallModeMask = 1;
-const kTurboFanICCallForUnptimizedCode = 0;
-const kTurboFanICCallForOptimizedCode = 1;
-
-code_stubs.MathFloorStub = function MathFloorStub(call_conv, minor_key) {
-  var call_from_optimized_ic = function(f, i, tv, receiver, v) {
-    "use strict";
-    // |f| is this function's JSFunction
-    // |i| is TypeFeedbackVector slot # of callee's CallIC for Math.floor call
-    // |receiver| is receiver, should not be used
-    // |tv| is the calling function's type vector
-    // |v| is the value to floor
-    if (f !== %_FixedArrayGet(tv, i|0)) {
-      return %_CallFunction(receiver, v, f);
-    }
-    var r = %_MathFloor(+v);
-    if (%_IsMinusZero(r)) {
-      // Collect type feedback when the result of the floor is -0. This is
-      // accomplished by storing a sentinel in the second, "extra"
-      // TypeFeedbackVector slot corresponding to the Math.floor CallIC call in
-      // the caller's TypeVector.
-      %_FixedArraySet(tv, ((i|0)+1)|0, 1);
-      return -0;
-    }
-    // Return integers in smi range as smis.
-    var trunc = r|0;
-    if (trunc === r) {
-      return trunc;
-    }
-    return r;
-  }
-  var call_mode = (minor_key & kTurboFanICCallModeMask);
-  if (call_mode == kTurboFanICCallForOptimizedCode) {
-    return call_from_optimized_ic;
-  } else {
-    %SetForceInlineFlag(call_from_optimized_ic);
-    var call_from_unoptimized_ic = function(f, i, receiver, v) {
-      var tv = %_GetTypeFeedbackVector(%_GetCallerJSFunction());
-      return call_from_optimized_ic(f, i, tv, receiver, v);
-    }
-    return call_from_unoptimized_ic;
-  }
-}
-
-})