[runtime] Rewrite Function.prototype.toString in C++.

src/debug/mirrors.js

 // Copyright 2006-2012 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.
 
 (function(global, utils) {
 "use strict";
 
 // ----------------------------------------------------------------------------
 // Imports
 
 var ErrorToString;
-var FunctionSourceString;
 var GlobalArray = global.Array;
 var IsNaN = global.isNaN;
 var JSONStringify = global.JSON.stringify;
 var MakeError;
 var MapEntries;
 var MapIteratorNext;
 var MathMin = global.Math.min;
 var promiseStatusSymbol = utils.ImportNow("promise_status_symbol");
 var promiseValueSymbol = utils.ImportNow("promise_value_symbol");
 var SetIteratorNext;
 var SetValues;
 var SymbolToString;
 
 utils.Import(function(from) {
   ErrorToString = from.ErrorToString;
-  FunctionSourceString = from.FunctionSourceString;
   MakeError = from.MakeError;
   MapEntries = from.MapEntries;
   MapIteratorNext = from.MapIteratorNext;
   SetIteratorNext = from.SetIteratorNext;
   SetValues = from.SetValues;
   SymbolToString = from.SymbolToString;
 });
 
 // ----------------------------------------------------------------------------
 
@@ skipping 892 matching lines @@
 
 /**
  * Returns the source code for the function.
  * @return {string or undefined} The source code for the function. If the
  *     function is not resolved undefined will be returned.
  */
 FunctionMirror.prototype.source = function() {
   // Return source if function is resolved. Otherwise just fall through to
   // return undefined.
   if (this.resolved()) {
-    return FunctionSourceString(this.value_);
+    return %FunctionToString(this.value_);

[Yang, 2015/12/22 06:19:22]

Alternatively, you could import global.Function.prototype.toString at the start
of this file and use it here. Then you don't have to introduce this %-function.

[Benedikt Meurer, 2015/12/22 06:30:35]

As per offline discussion: This doesn't work with the current bootstrapper
unfortunately because we need that in messages.js as well. So we'll keep it this
way instead for now.

   }
 };
 
 
 /**
  * Returns the script object for the function.
  * @return {ScriptMirror or undefined} Script object for the function or
  *     undefined if the function has no script
  */
 FunctionMirror.prototype.script = function() {
@@ skipping 2094 matching lines @@
 // Functions needed by the debugger runtime.
 utils.InstallFunctions(utils, DONT_ENUM, [
   "ClearMirrorCache", ClearMirrorCache
 ]);
 
 // Export to debug.js
 utils.Export(function(to) {
   to.MirrorType = MirrorType;
 });
 })