Introduce concurrent on-stack replacement.

test/mjsunit/compiler/optimized-for-in.js

 // 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: --optimize-for-in --allow-natives-syntax
+// Flags: --no-concurrent-osr
 
 // Test for-in support in Crankshaft.  For simplicity this tests assumes certain
 // fixed iteration order for properties and will have to be adjusted if V8
 // stops following insertion order.
 
 
 function a(t) {
   var result = [];
   for (var i in t) {
     result.push(i + t[i]);
@@ skipping 252 matching lines @@
   for (var i = 0; i < arr.length; i++) {
     arr[i] = i + 1;
   }
   arr.push(":");  // Force deopt at the end of the loop.
   assertEquals("211:x1234567891011121314151617181920:y", osr_inner({x: arr, y: arr}, (arr.length / 2) | 0));
   assertEquals("7x456y", osr_outer({x: [1,2,3], y: [4,5,6]}, "x"));
   assertEquals("101234567", osr_outer_and_deopt([1,2,3,4,5,6,7,8], "5"));
 }
 
 test_osr();