Introduce FieldIndex to unify and abstract property/field offset

test/mjsunit/outobject-double-for-in.js

Index: test/mjsunit/outobject-double-for-in.js
diff --git a/test/mjsunit/regress/regress-crbug-134055.js b/test/mjsunit/outobject-double-for-in.js
similarity index 66%
copy from test/mjsunit/regress/regress-crbug-134055.js
copy to test/mjsunit/outobject-double-for-in.js
index 9b658fb6f650f04520001f61f8e34d0202c5fb7d..eb8ac940a7f403af5db752d779a4b35acab0c6a1 100644
--- a/test/mjsunit/regress/regress-crbug-134055.js
+++ b/test/mjsunit/outobject-double-for-in.js
@@ -27,37 +27,40 @@
 
 // Flags: --allow-natives-syntax
 
-function crash(obj) {
-  return obj.foo;
+function DoubleContainer() {
+  this.x0 = 0.5;
+  this.x1 = undefined;
+  this.x2 = undefined;
+  this.x3 = undefined;
+  this.x4 = undefined;
+  this.x5 = undefined;
+  this.x6 = undefined;
+  this.x7 = 5;
+  this.x8 = undefined;
+  this.x9 = undefined;
+  this.x10 = undefined;
+  this.x11 = undefined;
+  this.x12 = undefined;
+  this.x13 = undefined;
+  this.x14 = undefined;
+  this.x15 = undefined;
+  this.x16 = true;
+  this.y = 2.5;
 }
 
-function base(number_of_properties) {
-  var result = new Array();
-  for (var i = 0; i < number_of_properties; i++) {
-    result["property" + i] = "value" + i;
+var z = new DoubleContainer();
+
+function test_props(a) {
+  for (var i in a) {
+    assertTrue(i !== "x0" || a[i] === 0.5);
+    assertTrue(i !== "y" || a[i] === 2.5);
+    assertTrue(i !== "x12" || a[i] === undefined);
+    assertTrue(i !== "x16" || a[i] === true);
+    assertTrue(i !== "x7" || a[i] === 5);
   }
-  result.foo = number_of_properties;
-  return result;
 }
 
-var a = base(12);
-var b = base(13);
-var c = base(14);
-var d = base(15);
-
-crash(a);  // Premonomorphic.
-crash(a);
-crash(b);
-crash(c);
-crash(d);  // Polymorphic, degree 4.
-
-//Prepare ElementsKind transition map chain.
-var x = base(13);
-x[0] = "object";
-x = base(14);
-x[0] = "object";
-x = base(15);
-x[0] = "object";
-
-%OptimizeFunctionOnNextCall(crash);
-crash(a);
+test_props(z);
+test_props(z);
+%OptimizeFunctionOnNextCall(test_props);
+test_props(z);