From ec4c772746d7f56ef20b94b8a8c46184f02d96b3 Mon Sep 17 00:00:00 2001
From: "vegorov@chromium.org"
 <vegorov@chromium.org@ce2b1a6d-e550-0410-aec6-3dcde31c8c00>
Date: Thu, 12 Apr 2012 19:32:29 +0000
Subject: [PATCH] Return LOOKUP variable instead of CONTEXT for non-context
 allocated outer scope parameters.

R=kmillikin@chromium.org
BUG=chromium:119609
TEST=test/mjsunit/regress/regress-119609.js

Review URL: https://chromiumcodereview.appspot.com/10010046

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@11298 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
---
 src/scopes.cc                          | 17 +++++---
 test/mjsunit/regress/regress-119609.js | 71 ++++++++++++++++++++++++++++++++++
 2 files changed, 83 insertions(+), 5 deletions(-)
 create mode 100644 test/mjsunit/regress/regress-119609.js

diff --git a/src/scopes.cc b/src/scopes.cc
index 859cbd1..1e35e48 100644
--- a/src/scopes.cc
+++ b/src/scopes.cc
@@ -388,14 +388,17 @@ Variable* Scope::LocalLookup(Handle<String> name) {
 
   // Check context slot lookup.
   VariableMode mode;
+  Variable::Location location = Variable::CONTEXT;
   InitializationFlag init_flag;
   int index = scope_info_->ContextSlotIndex(*name, &mode, &init_flag);
   if (index < 0) {
     // Check parameters.
-    mode = VAR;
-    init_flag = kCreatedInitialized;
     index = scope_info_->ParameterIndex(*name);
     if (index < 0) return NULL;
+
+    mode = DYNAMIC;
+    location = Variable::LOOKUP;
+    init_flag = kCreatedInitialized;
   }
 
   Variable* var =
@@ -405,7 +408,7 @@ Variable* Scope::LocalLookup(Handle<String> name) {
                          true,
                          Variable::NORMAL,
                          init_flag);
-  var->AllocateTo(Variable::CONTEXT, index);
+  var->AllocateTo(location, index);
   return var;
 }
 
@@ -949,10 +952,14 @@ bool Scope::ResolveVariable(CompilationInfo* info,
       break;
 
     case BOUND_EVAL_SHADOWED:
-      // We found a variable variable binding that might be shadowed
-      // by 'eval' introduced variable bindings.
+      // We either found a variable binding that might be shadowed by eval  or
+      // gave up on it (e.g. by encountering a local with the same in the outer
+      // scope which was not promoted to a context, this can happen if we use
+      // debugger to evaluate arbitrary expressions at a break point).
       if (var->is_global()) {
         var = NonLocal(proxy->name(), DYNAMIC_GLOBAL);
+      } else if (var->is_dynamic()) {
+        var = NonLocal(proxy->name(), DYNAMIC);
       } else {
         Variable* invalidated = var;
         var = NonLocal(proxy->name(), DYNAMIC_LOCAL);
diff --git a/test/mjsunit/regress/regress-119609.js b/test/mjsunit/regress/regress-119609.js
new file mode 100644
index 0000000..af4335b
--- /dev/null
+++ b/test/mjsunit/regress/regress-119609.js
@@ -0,0 +1,71 @@
+// Copyright 2012 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: --expose-debug-as debug
+
+Debug = debug.Debug;
+
+var exception = false;
+
+function listener(event, exec_state, event_data, data) {
+  try {
+    if (event == Debug.DebugEvent.Break) {
+      function lookup(name) {
+	return exec_state.frame(0).evaluate(name).value();
+      }
+
+      assertEquals(3, lookup("e"));
+      assertEquals(4, lookup("f"));
+      assertEquals(1, lookup("a"));
+
+      try {
+	assertEquals(2, lookup("b"));
+      } catch (e) {
+	assertEquals("ReferenceError: b is not defined", e.toString());
+      }
+    }
+  } catch (e) {
+    exception = e.toString() + e.stack;
+  }
+}
+
+Debug.setListener(listener);
+
+function f(a, b) {
+  var c = 3;
+  function d(e, f) {
+    var g = a;
+    var h = c;
+    debugger;
+  }
+
+  return d;
+}
+
+f(1, 2)(3, 4);
+
+assertFalse(exception);
-- 
2.7.4