pessimistic.js

/*******************************************************************************
 * Copyright (c) 2013 Max Schaefer.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     Max Schaefer - initial API and implementation
 *******************************************************************************/

/* Pessimistic call graph builder. */
if(typeof define !== 'function') {
  var define = require('amdefine')(module);
}

define(function(require, exports) {
  var graph = require('./graph'),
      natives = require('./natives'),
      flowgraph = require('./flowgraph'),
      callgraph = require('./callgraph');

  function addOneShotEdges(ast, fg) {
    // set up flow for one-shot calls
    ast.attr.functions.forEach(function(fn) {
      var parent = fn.attr.parent,
          childProp = fn.attr.childProp;

      if(childProp === 'callee' && parent &&
         (parent.type === 'CallExpression' || parent.type === 'NewExpression')) {
        // one-shot closure
        parent.attr.oneshot = true;
        for(var i=0,nargs=parent.arguments.length;i<nargs;++i) {
          if(i >= fn.params.length)
            break;
          fg.addEdge(flowgraph.argVertex(parent, i+1), flowgraph.parmVertex(fn, i+1));
        }
        fg.addEdge(flowgraph.retVertex(fn), flowgraph.resVertex(parent));
      } else {
        // not a one-shot closure
        for(var i=0,nparms=fn.params.length;i<=nparms;++i)
          fg.addEdge(flowgraph.unknownVertex(), flowgraph.parmVertex(fn, i));
        fg.addEdge(flowgraph.retVertex(fn), flowgraph.unknownVertex());
      }
    });

    // set up flow for all other calls
    ast.attr.calls.forEach(function(call) {
      if(!call.attr.oneshot)
        for(var i=0,nargs=call.arguments.length;i<=nargs;++i)
          fg.addEdge(flowgraph.argVertex(call, i), flowgraph.unknownVertex());
        fg.addEdge(flowgraph.unknownVertex(), flowgraph.resVertex(call));
    });
  }

  function buildCallGraph(ast, noOneShot) {
	var fg = new graph.Graph();
  	natives.addNativeFlowEdges(fg);
  	if(!noOneShot)
  	  addOneShotEdges(ast, fg);
  	flowgraph.addIntraproceduralFlowGraphEdges(ast, fg);
  	return callgraph.extractCG(ast, fg);
  }

  exports.buildCallGraph = buildCallGraph;
  return exports;
});