Reland "Customized support for feedback on calls to Array." and follow-up fixes.

test/mjsunit/array-feedback.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
@@ skipping 67 matching lines @@
     expected = elements_kind.fast;
   }
   assertEquals(expected, getKind(obj), name_opt);
 }
 
 if (support_smi_only_arrays) {
 
   // Verify that basic elements kind feedback works for non-constructor
   // array calls (as long as the call is made through an IC, and not
   // a CallStub).
-  // (function (){
-  //   function create0() {
-  //     return Array();
-  //   }
+  (function (){
+    function create0() {
+      return Array();
+    }
 
-  //   // Calls through ICs need warm up through uninitialized, then
-  //   // premonomorphic first.
-  //   create0();
-  //   create0();
-  //   a = create0();
-  //   assertKind(elements_kind.fast_smi_only, a);
-  //   a[0] = 3.5;
-  //   b = create0();
-  //   assertKind(elements_kind.fast_double, b);
+    // Calls through ICs need warm up through uninitialized, then
+    // premonomorphic first.
+    create0();
+    a = create0();
+    assertKind(elements_kind.fast_smi_only, a);
+    a[0] = 3.5;
+    b = create0();
+    assertKind(elements_kind.fast_double, b);
 
-  //   function create1(arg) {
-  //     return Array(arg);
-  //   }
+    function create1(arg) {
+      return Array(arg);
+    }
 
-  //   create1(0);
-  //   create1(0);
-  //   a = create1(0);
-  //   assertFalse(isHoley(a));
-  //   assertKind(elements_kind.fast_smi_only, a);
-  //   a[0] = "hello";
-  //   b = create1(10);
-  //   assertTrue(isHoley(b));
-  //   assertKind(elements_kind.fast, b);
+    create1(0);
+    create1(0);
+    a = create1(0);
+    assertFalse(isHoley(a));
+    assertKind(elements_kind.fast_smi_only, a);
+    a[0] = "hello";
+    b = create1(10);
+    assertTrue(isHoley(b));
+    assertKind(elements_kind.fast, b);
 
-  //   a = create1(100000);
-  //   assertKind(elements_kind.dictionary, a);
+    a = create1(100000);
+    assertKind(elements_kind.dictionary, a);
 
-  //   function create3(arg1, arg2, arg3) {
-  //     return Array(arg1, arg2, arg3);
-  //   }
+    function create3(arg1, arg2, arg3) {
+      return Array(arg1, arg2, arg3);
+    }
 
-  //   create3();
-  //   create3();
-  //   a = create3(1,2,3);
-  //   a[0] = 3.5;
-  //   b = create3(1,2,3);
-  //   assertKind(elements_kind.fast_double, b);
-  //   assertFalse(isHoley(b));
-  // })();
+    create3(1,2,3);
+    create3(1,2,3);
+    a = create3(1,2,3);
+    a[0] = 3.035;
+    assertKind(elements_kind.fast_double, a);
+    b = create3(1,2,3);
+    assertKind(elements_kind.fast_double, b);
+    assertFalse(isHoley(b));
+  })();
 
 
   // Verify that keyed calls work
-  // (function (){
-  //   function create0(name) {
-  //     return this[name]();
-  //   }
+  (function (){
+    function create0(name) {
+      return this[name]();
+    }
 
-  //   name = "Array";
-  //   create0(name);
-  //   create0(name);
-  //   a = create0(name);
-  //   a[0] = 3.5;
-  //   b = create0(name);
-  //   assertKind(elements_kind.fast_double, b);
-  // })();
+    name = "Array";
+    create0(name);
+    create0(name);
+    a = create0(name);
+    a[0] = 3.5;
+    b = create0(name);
+    assertKind(elements_kind.fast_double, b);
+  })();
 
 
-  // Verify that the IC can't be spoofed by patching
+  // Verify that feedback is turned off if the call site goes megamorphic.
+  (function (){
+    function foo(arg) { return arg(); }
+    foo(Array);
+    foo(function() {});
+    foo(Array);
+
+    gc();
+
+    a = foo(Array);
+    a[0] = 3.5;
+    b = foo(Array);
+    // b doesn't benefit from elements kind feedback at a megamorphic site.
+    assertKind(elements_kind.fast_smi_only, b);
+  })();
+
+
+  // Verify that crankshaft consumes type feedback.
   (function (){
     function create0() {
       return Array();
     }
 
     create0();
     create0();
     a = create0();
-    assertKind(elements_kind.fast_smi_only, a);
-    var oldArray = this.Array;
-    this.Array = function() { return ["hi"]; };
+    a[0] = 3.5;
+    %OptimizeFunctionOnNextCall(create0);
+    create0();
+    create0();
     b = create0();
-    assertEquals(["hi"], b);
-    this.Array = oldArray;
+    assertKind(elements_kind.fast_double, b);
+    assertOptimized(create0);
+
+    function create1(arg) {
+      return Array(arg);
+    }
+
+    create1(8);
+    create1(8);
+    a = create1(8);
+    a[0] = 3.5;
+    %OptimizeFunctionOnNextCall(create1);
+    b = create1(8);
+    assertKind(elements_kind.fast_double, b);
+    assertOptimized(create1);
+
+    function createN(arg1, arg2, arg3) {
+      return Array(arg1, arg2, arg3);
+    }
+
+    createN(1, 2, 3);
+    createN(1, 2, 3);
+    a = createN(1, 2, 3);
+    a[0] = 3.5;
+    %OptimizeFunctionOnNextCall(createN);
+    b = createN(1, 2, 3);
+    assertKind(elements_kind.fast_double, b);
+    assertOptimized(createN);
   })();
 
-  // Verify that calls are still made through an IC after crankshaft,
-  // though the type information is reset.
-  // TODO(mvstanton): instead, consume the type feedback gathered up
-  // until crankshaft time.
-  // (function (){
-  //   function create0() {
-  //     return Array();
-  //   }
-
-  //   create0();
-  //   create0();
-  //   a = create0();
-  //   a[0] = 3.5;
-  //   %OptimizeFunctionOnNextCall(create0);
-  //   create0();
-  //   // This test only makes sense if crankshaft is allowed
-  //   if (4 != %GetOptimizationStatus(create0)) {
-  //     create0();
-  //     b = create0();
-  //     assertKind(elements_kind.fast_smi_only, b);
-  //     b[0] = 3.5;
-  //     c = create0();
-  //     assertKind(elements_kind.fast_double, c);
-  //     assertOptimized(create0);
-  //   }
-  // })();
-
-
   // Verify that cross context calls work
   (function (){
     var realmA = Realm.current();
     var realmB = Realm.create();
     assertEquals(0, realmA);
     assertEquals(1, realmB);
 
     function instanceof_check(type) {
       assertTrue(type() instanceof type);
       assertTrue(type(5) instanceof type);
       assertTrue(type(1,2,3) instanceof type);
     }
 
     var realmBArray = Realm.eval(realmB, "Array");
     instanceof_check(Array);
     instanceof_check(Array);
     instanceof_check(Array);
     instanceof_check(realmBArray);
     instanceof_check(realmBArray);
     instanceof_check(realmBArray);
   })();
 }