Fix for issue 545: don't reuse this VariableProxy.

Review URL: http://codereview.chromium.org/464069


git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@3432 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/compiler.cc

@@ -56,6 +56,8 @@ class CodeGenSelector: public AstVisitor {
  private:
   // Visit an expression in a given expression context.
   void ProcessExpression(Expression* expr, Expression::Context context) {
+    ASSERT(expr->context() == Expression::kUninitialized ||
+           expr->context() == context);
     Expression::Context saved = context_;
     context_ = context;
     Visit(expr);

src/scopes.cc

@@ -189,8 +189,7 @@ void Scope::Initialize(bool inside_with) {
       variables_.Declare(this, Factory::this_symbol(), Variable::VAR,
                          false, Variable::THIS);
   var->rewrite_ = new Slot(var, Slot::PARAMETER, -1);
-  receiver_ = new VariableProxy(Factory::this_symbol(), true, false);
-  receiver_->BindTo(var);
+  receiver_ = var;
 
   if (is_function_scope()) {
     // Declare 'arguments' variable which exists in all functions.

src/scopes.h

@@ -206,8 +206,13 @@ class Scope: public ZoneObject {
   // ---------------------------------------------------------------------------
   // Accessors.
 
-  // The variable corresponding to the (function) receiver.
-  VariableProxy* receiver() const  { return receiver_; }
+  // A new variable proxy corresponding to the (function) receiver.
+  VariableProxy* receiver() const {
+    VariableProxy* proxy =
+        new VariableProxy(Factory::this_symbol(), true, false);
+    proxy->BindTo(receiver_);
+    return proxy;
+  }
 
   // The variable holding the function literal for named function
   // literals, or NULL.
@@ -314,7 +319,7 @@ class Scope: public ZoneObject {
   // Declarations.
   ZoneList<Declaration*> decls_;
   // Convenience variable.
-  VariableProxy* receiver_;
+  Variable* receiver_;
   // Function variable, if any; function scopes only.
   Variable* function_;
   // Convenience variable; function scopes only.

test/mjsunit/regress/regress-545.js

+// Copyright 2009 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// See: http://code.google.com/p/v8/issues/detail?id=545
+// and: http://code.google.com/p/chromium/issues/detail?id=28353
+
+// The "this" variable proxy was reused. If context annotations differ between
+// uses, this can cause a use in a value context to assume a test context. Since
+// it has no true/false labels set, it causes a null-pointer dereference and
+// segmentation fault.
+
+// Code should not crash:
+
+// Original bug report by Robert Swiecki (wrapped to not throw):
+try {
+ new IsPrimitive(load())?this.join():String('
').charCodeAt((!this>Math));
+} catch (e) {}
+
+// Shorter examples:
+
+this + !this;
+
+this + (this ? 1 : 2);