From e08bc60c38f91ee9d9585c2d4ad564c6b9a1622f Mon Sep 17 00:00:00 2001
From: ksen <ksen@cs.berkeley.edu>
Date: Thu, 6 Feb 2014 08:27:27 -0800
Subject: [PATCH] fixed issue #43

---
 src/js/instrument/esnstrument.js | 38 +++++++++++++++++++++++++++++++-
 tests/unit/shadow-arguments.js   | 23 ++++++++++++++-----
 2 files changed, 54 insertions(+), 7 deletions(-)

diff --git a/src/js/instrument/esnstrument.js b/src/js/instrument/esnstrument.js
index fc00ece1..08ddc333 100644
--- a/src/js/instrument/esnstrument.js
+++ b/src/js/instrument/esnstrument.js
@@ -1173,6 +1173,13 @@
             }
         };
 
+        Scope.prototype.hasOwnVar = function (name) {
+            var s = this;
+            if (s && HOP(s.vars, name))
+                return s.vars[name];
+            return null;
+        };
+
         Scope.prototype.hasVar = function (name) {
             var s = this;
             while (s !== null) {
@@ -1210,6 +1217,10 @@
 
         var currentScope = null;
 
+        // rename arguments to J$_arguments
+        var fromName = 'arguments';
+        var toName = astUtil.JALANGI_VAR+"_arguments";
+
         function handleFun(node) {
             var oldScope = currentScope;
             currentScope = new Scope(currentScope);
@@ -1217,6 +1228,9 @@
             if (node.type === 'FunctionDeclaration') {
                 oldScope.addVar(node.id.name, "defun", node.loc);
                 MAP(node.params, function (param) {
+                    if (param.name === fromName) {         // rename arguments to J$_arguments
+                        param.name = toName;
+                    }
                     currentScope.addVar(param.name, "arg");
                 });
             } else if (node.type === 'FunctionExpression') {
@@ -1224,6 +1238,9 @@
                     currentScope.addVar(node.id.name, "lambda");
                 }
                 MAP(node.params, function (param) {
+                    if (param.name === fromName) {         // rename arguments to J$_arguments
+                        param.name = toName;
+                    }
                     currentScope.addVar(param.name, "arg");
                 });
             }
@@ -1253,7 +1270,26 @@
         var visitorPost = {
             'Program':popScope,
             'FunctionDeclaration':popScope,
-            'FunctionExpression':popScope
+            'FunctionExpression':popScope,
+            'Identifier':function (node, context) {         // rename arguments to J$_arguments
+                if (context === astUtil.CONTEXT.RHS  && node.name === fromName && currentScope.hasOwnVar(toName)) {
+                    node.name = toName;
+                }
+                return node;
+            },
+            "UpdateExpression":function (node) {         // rename arguments to J$_arguments
+                if (node.argument.type === 'Identifier' && node.argument.name === fromName && currentScope.hasOwnVar(toName)) {
+                    node.argument.name = toName;
+                }
+                return node;
+            },
+            "AssignmentExpression":function (node) {         // rename arguments to J$_arguments
+                if (node.left.type === 'Identifier' && node.left.name === fromName && currentScope.hasOwnVar(toName)) {
+                    node.left.name = toName;
+                }
+                return node;
+            }
+
         };
         astUtil.transformAst(ast, visitorPost, visitorPre);
     }
diff --git a/tests/unit/shadow-arguments.js b/tests/unit/shadow-arguments.js
index a5df213c..8b881663 100644
--- a/tests/unit/shadow-arguments.js
+++ b/tests/unit/shadow-arguments.js
@@ -1,6 +1,17 @@
- var a = function a(b, arguments) {
-            };
-var D = function () {
-                a.call(null, false, null);
-};
-new D();
+function a(b, arguments) {
+    var x = arguments;
+    arguments++;
+    arguments += 4;
+    arguments = arguments + 4;
+    arguments[0] = 2;
+    arguments.callee = 'x';
+    f(arguments);
+}
+
+function f(x) {}
+
+function b() {
+    var x = arguments;
+    var y = arguments.callee;
+    var z = arguments[0];
+}