Fix off-by-one error in AstTyper.

This causes the first parameter to be confused with the first
stack local when we collect type information.

R=jkummerow@chromium.org

Review URL: https://codereview.chromium.org/105943007

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@18296 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/typing.h

@@ -84,7 +84,7 @@ class AstTyper: public AstVisitor {
 
   int variable_index(Variable* var) {
     return var->IsStackLocal() ? var->index() :
-           var->IsParameter() ? -var->index() : kNoVar;
+           var->IsParameter() ? -var->index() - 1 : kNoVar;
   }
 
   void VisitDeclarations(ZoneList<Declaration*>* declarations);

test/mjsunit/regress/regress-param-local-type.js

+// Copyright 2013 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.
+
+// Flags: --allow-natives-syntax
+
+// Test that we do not confuse the first local and the first parameter
+// when gathering type information.
+
+function f(a) {  // First parameter is tagged.
+  var s = '';    // First local has string type.
+  var n = 0;
+  var i = 1;
+  n = i + a;
+}
+
+f(1);
+f(1);
+%OptimizeFunctionOnNextCall(f);
+f(1);
+assertOptimized(f);