Bugfix in hydrogen array literal code generation.

If an array literal contains some non-constant elements, is of type SMI, and
then the boilerplate transitions to double or fast sometime after we've
crankshafted the code, then we could incorrectly store smis in double arrays.

BUG=
R=yangguo@chromium.org

Review URL: https://codereview.chromium.org/17334004

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@15207 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/hydrogen.cc

@@ -6064,6 +6064,11 @@ void HOptimizedGraphBuilder::VisitArrayLiteral(ArrayLiteral* expr) {
                                  isolate()->factory()->empty_string(),
                                  Runtime::FunctionForId(function_id),
                                  3));
+
+    // De-opt if elements kind changed from boilerplate_elements_kind.
+    Handle<Map> map = Handle<Map>(original_boilerplate_object->map(),
+                                  isolate());
+    AddInstruction(HCheckMaps::New(literal, map, zone()));
   }
 
   // The array is expected in the bailout environment during computation

test/mjsunit/array-literal-feedback.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 --smi-only-arrays --expose-gc
+// Flags: --track-allocation-sites --noalways-opt
+
+// Test element kind of objects.
+// Since --smi-only-arrays affects builtins, its default setting at compile
+// time sticks if built with snapshot.  If --smi-only-arrays is deactivated
+// by default, only a no-snapshot build actually has smi-only arrays enabled
+// in this test case.  Depending on whether smi-only arrays are actually
+// enabled, this test takes the appropriate code path to check smi-only arrays.
+
+// support_smi_only_arrays = %HasFastSmiElements(new Array(1,2,3,4,5,6,7,8));
+support_smi_only_arrays = true;
+
+if (support_smi_only_arrays) {
+  print("Tests include smi-only arrays.");
+} else {
+  print("Tests do NOT include smi-only arrays.");
+}
+
+if (support_smi_only_arrays) {
+
+  function get_literal(x) {
+    var literal = [1, 2, x];
+    return literal;
+  }
+
+  get_literal(3);
+  get_literal(3);
+  %OptimizeFunctionOnNextCall(get_literal);
+  a = get_literal(3);
+  assertTrue(2 != %GetOptimizationStatus(get_literal));
+  assertTrue(%HasFastSmiElements(a));
+  a[0] = 3.5;
+
+  // We should have transitioned the boilerplate array to double, and
+  // crankshafted code should de-opt on the unexpected elements kind
+  b = get_literal(3);
+  assertTrue(%HasFastDoubleElements(b));
+  assertEquals([1, 2, 3], b);
+  assertTrue(1 != %GetOptimizationStatus(get_literal));
+
+  // Optimize again
+  get_literal(3);
+  %OptimizeFunctionOnNextCall(get_literal);
+  b = get_literal(3);
+  assertTrue(%HasFastDoubleElements(b));
+  assertTrue(2 != %GetOptimizationStatus(get_literal));
+}