Fix a stack height mismatch when deoptimizing.

When deoptimizing from the key subexpression of a keyed arguments access,
the unoptimized code expects to find the value of the receiver on the
expression stack.  The environment of the optimizing compiler did not
contain this value during evaluation of the key subexpression.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@6981 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

diff --git a/src/hydrogen.cc b/src/hydrogen.cc
index 2de70ff..c4eae9a 100644 (file)
--- a/src/hydrogen.cc
+++ b/src/hydrogen.cc
@@ -3830,9 +3830,11 @@ bool HGraphBuilder::TryArgumentsAccess(Property* expr) {
     HInstruction* elements = AddInstruction(new HArgumentsElements);
     result = new HArgumentsLength(elements);
   } else {
+    Push(graph()->GetArgumentsObject());
     VisitForValue(expr->key());
     if (HasStackOverflow()) return false;
     HValue* key = Pop();
+    Drop(1);  // Arguments object.
     HInstruction* elements = AddInstruction(new HArgumentsElements);
     HInstruction* length = AddInstruction(new HArgumentsLength(elements));
     AddInstruction(new HBoundsCheck(key, length));

diff --git a/test/mjsunit/regress/regress-1210.js b/test/mjsunit/regress/regress-1210.js
new file mode 100644 (file)
index 0000000..9c708a5
--- /dev/null
+++ b/test/mjsunit/regress/regress-1210.js
@@ -0,0 +1,48 @@
+// Copyright 2011 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.
+
+// Deoptimization of the key expression in an arguments access should see
+// the arguments object as the value of the receiver.
+
+var a = 0;
+
+function observe(x, y) { return x; }
+
+function side_effect(x) { a = x; }
+
+function test() {
+  // We will trigger deoptimization of 'a + 0' which should bail out to
+  // immediately after the call to 'side_effect' (i.e., still in the key
+  // subexpression of the arguments access).
+  return observe(a, arguments[side_effect(a), a + 0]);
+}
+
+// Run enough to optimize assuming global 'a' is a smi.
+for (var i = 0; i < 1000000; ++i) test(0);
+
+a = "hello";
+test(0);