allocation-site-info.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: --allow-natives-syntax --expose-gc --opt --no-always-opt

var elements_kind = {
  fast_smi_only            :  'fast smi only elements',
  fast                     :  'fast elements',
  fast_double              :  'fast double elements',
  dictionary               :  'dictionary elements',
  external_byte            :  'external byte elements',
  external_unsigned_byte   :  'external unsigned byte elements',
  external_short           :  'external short elements',
  external_unsigned_short  :  'external unsigned short elements',
  external_int             :  'external int elements',
  external_unsigned_int    :  'external unsigned int elements',
  external_float           :  'external float elements',
  external_double          :  'external double elements',
  external_pixel           :  'external pixel elements'
}

function getKind(obj) {
  if (%HasSmiElements(obj)) return elements_kind.fast_smi_only;
  if (%HasObjectElements(obj)) return elements_kind.fast;
  if (%HasDoubleElements(obj)) return elements_kind.fast_double;
  if (%HasDictionaryElements(obj)) return elements_kind.dictionary;
}

function isHoley(obj) {
  if (%HasHoleyElements(obj)) return true;
  return false;
}

function assertKind(expected, obj, name_opt) {
  assertEquals(expected, getKind(obj), name_opt);
}

function assertHoley(obj, name_opt) {
  assertEquals(true, isHoley(obj), name_opt);
}

function assertNotHoley(obj, name_opt) {
  assertEquals(false, isHoley(obj), name_opt);
}

obj = [];
assertNotHoley(obj);
assertKind(elements_kind.fast_smi_only, obj);

obj = [1, 2, 3];
assertNotHoley(obj);
assertKind(elements_kind.fast_smi_only, obj);

obj = new Array();
assertNotHoley(obj);
assertKind(elements_kind.fast_smi_only, obj);

obj = new Array(0);
assertHoley(obj);
assertKind(elements_kind.fast_smi_only, obj);

obj = new Array(2);
assertHoley(obj);
assertKind(elements_kind.fast_smi_only, obj);

obj = new Array(1,2,3);
assertNotHoley(obj);
assertKind(elements_kind.fast_smi_only, obj);

obj = new Array(1, "hi", 2, undefined);
assertNotHoley(obj);
assertKind(elements_kind.fast, obj);

function fastliteralcase(literal, value) {
  literal[0] = value;
  return literal;
}

function get_standard_literal() {
  var literal = [1, 2, 3];
  return literal;
}

%PrepareFunctionForOptimization(get_standard_literal);

// Case: [1,2,3] as allocation site
obj = fastliteralcase(get_standard_literal(), 1);
assertKind(elements_kind.fast_smi_only, obj);
obj = fastliteralcase(get_standard_literal(), 1.5);
assertKind(elements_kind.fast_double, obj);
obj = fastliteralcase(get_standard_literal(), 2);
assertKind(elements_kind.fast_double, obj);

// The test below is in a loop because arrays that live
// at global scope without the chance of being recreated
// don't have allocation site information attached.
for (i = 0; i < 2; i++) {
  obj = fastliteralcase([5, 3, 2], 1.5);
  assertKind(elements_kind.fast_double, obj);
  obj = fastliteralcase([3, 6, 2], 1.5);
  assertKind(elements_kind.fast_double, obj);

  // Note: thanks to pessimistic transition store stubs, we'll attempt
  // to transition to the most general elements kind seen at a particular
  // store site. So, the elements kind will be double.
  obj = fastliteralcase([2, 6, 3], 2);
  assertKind(elements_kind.fast_double, obj);
}

// Verify that we will not pretransition the double->fast path.
obj = fastliteralcase(get_standard_literal(), "elliot");
assertKind(elements_kind.fast, obj);
obj = fastliteralcase(get_standard_literal(), 3);
assertKind(elements_kind.fast, obj);

// Make sure this works in optimized code too.
  %OptimizeFunctionOnNextCall(get_standard_literal);
get_standard_literal();
obj = get_standard_literal();
assertKind(elements_kind.fast, obj);

function fastliteralcase_smifast(value) {
  var literal = [1, 2, 3, 4];
  literal[0] = value;
  return literal;
}

obj = fastliteralcase_smifast(1);
assertKind(elements_kind.fast_smi_only, obj);
obj = fastliteralcase_smifast("carter");
assertKind(elements_kind.fast, obj);
obj = fastliteralcase_smifast(2);
assertKind(elements_kind.fast, obj);

// Case: make sure transitions from packed to holey are tracked
function fastliteralcase_smiholey(index, value) {
  var literal = [1, 2, 3, 4];
  literal[index] = value;
  return literal;
}

obj = fastliteralcase_smiholey(5, 1);
assertKind(elements_kind.fast_smi_only, obj);
assertHoley(obj);
obj = fastliteralcase_smiholey(0, 1);
assertKind(elements_kind.fast_smi_only, obj);
assertHoley(obj);

function newarraycase_smidouble(value) {
  var a = new Array();
  a[0] = value;
  return a;
}

// Case: new Array() as allocation site, smi->double
obj = newarraycase_smidouble(1);
assertKind(elements_kind.fast_smi_only, obj);
obj = newarraycase_smidouble(1.5);
assertKind(elements_kind.fast_double, obj);
obj = newarraycase_smidouble(2);
assertKind(elements_kind.fast_double, obj);

function newarraycase_smiobj(value) {
  var a = new Array();
  a[0] = value;
  return a;
}

// Case: new Array() as allocation site, smi->fast
obj = newarraycase_smiobj(1);
assertKind(elements_kind.fast_smi_only, obj);
obj = newarraycase_smiobj("gloria");
assertKind(elements_kind.fast, obj);
obj = newarraycase_smiobj(2);
assertKind(elements_kind.fast, obj);

function newarraycase_length_smidouble(value) {
  var a = new Array(3);
  a[0] = value;
  return a;
}

// Case: new Array(length) as allocation site
obj = newarraycase_length_smidouble(1);
assertKind(elements_kind.fast_smi_only, obj);
obj = newarraycase_length_smidouble(1.5);
assertKind(elements_kind.fast_double, obj);
obj = newarraycase_length_smidouble(2);
assertKind(elements_kind.fast_double, obj);

// Try to continue the transition to fast object.
// TODO(mvstanton): re-enable commented out code when
// FLAG_pretenuring_call_new is turned on in the build.
obj = newarraycase_length_smidouble("coates");
assertKind(elements_kind.fast, obj);
obj = newarraycase_length_smidouble(2);
// assertKind(elements_kind.fast, obj);

function newarraycase_length_smiobj(value) {
  var a = new Array(3);
  a[0] = value;
  return a;
}

// Case: new Array(<length>) as allocation site, smi->fast
obj = newarraycase_length_smiobj(1);
assertKind(elements_kind.fast_smi_only, obj);
obj = newarraycase_length_smiobj("gloria");
assertKind(elements_kind.fast, obj);
obj = newarraycase_length_smiobj(2);
assertKind(elements_kind.fast, obj);

function newarraycase_list_smidouble(value) {
  var a = new Array(1, 2, 3);
  a[0] = value;
  return a;
}

obj = newarraycase_list_smidouble(1);
assertKind(elements_kind.fast_smi_only, obj);
obj = newarraycase_list_smidouble(1.5);
assertKind(elements_kind.fast_double, obj);
obj = newarraycase_list_smidouble(2);
assertKind(elements_kind.fast_double, obj);

function newarraycase_list_smiobj(value) {
  var a = new Array(4, 5, 6);
  a[0] = value;
  return a;
}

obj = newarraycase_list_smiobj(1);
assertKind(elements_kind.fast_smi_only, obj);
obj = newarraycase_list_smiobj("coates");
assertKind(elements_kind.fast, obj);
obj = newarraycase_list_smiobj(2);
assertKind(elements_kind.fast, obj);

// Perform a gc because without it the test below can experience an
// allocation failure at an inconvenient point. Allocation mementos get
// cleared on gc, and they can't deliver elements kind feedback when that
// happens.
gc();

// Case: array constructor calls with out of date feedback.
// The boilerplate should incorporate all feedback, but the input array
// should be minimally transitioned based on immediate need.
(function() {
  function foo(i) {
    // We have two cases, one for literals one for constructed arrays.
    var a = (i == 0)
      ? [1, 2, 3]
      : new Array(1, 2, 3);
    return a;
  }

  for (var i = 0; i < 2; i++) {
    a = foo(i);
    b = foo(i);
    b[5] = 1;  // boilerplate goes holey
    assertHoley(foo(i));
    a[0] = 3.5;  // boilerplate goes holey double
    assertKind(elements_kind.fast_double, a);
    assertNotHoley(a);
    var c = foo(i);
    assertKind(elements_kind.fast_double, c);
    assertHoley(c);
  }
})();

function newarraycase_onearg(len, value) {
  var a = new Array(len);
  a[0] = value;
  return a;
}

obj = newarraycase_onearg(5, 3.5);
assertKind(elements_kind.fast_double, obj);
obj = newarraycase_onearg(10, 5);
assertKind(elements_kind.fast_double, obj);
obj = newarraycase_onearg(0, 5);
assertKind(elements_kind.fast_double, obj);

// Verify that cross context calls work
var realmA = Realm.current();
var realmB = Realm.create();
assertEquals(0, realmA);
assertEquals(1, realmB);

function instanceof_check(type) {
  assertTrue(new type() instanceof type);
  assertTrue(new type(5) instanceof type);
  assertTrue(new type(1,2,3) instanceof type);
}

function instanceof_check2(type) {
  assertTrue(new type() instanceof type);
  assertTrue(new type(5) instanceof type);
  assertTrue(new type(1,2,3) instanceof type);
}

%PrepareFunctionForOptimization(instanceof_check);

var realmBArray = Realm.eval(realmB, "Array");
// Two calls with Array because ES6 instanceof desugars into a load of Array,
// and load has a premonomorphic state.
instanceof_check(Array);
instanceof_check(Array);
instanceof_check(realmBArray);

// instanceof_check2 is here because the call site goes through a state.
// Since instanceof_check(Array) was first called with the current context
// Array function, it went from (uninit->Array) then (Array->megamorphic).
// We'll get a different state traversal if we start with realmBArray.
// It'll go (uninit->realmBArray) then (realmBArray->megamorphic). Recognize
// that state "Array" implies an AllocationSite is present, and code is
// configured to use it.

// Two calls with realmBArray because ES6 instanceof desugars into a load of
// realmBArray, and load has a premonomorphic state.
instanceof_check2(realmBArray);
instanceof_check2(realmBArray);
instanceof_check2(Array);

  %OptimizeFunctionOnNextCall(instanceof_check);

// No de-opt will occur because HCallNewArray wasn't selected, on account of
// the call site not being monomorphic to Array.
instanceof_check(Array);
assertOptimized(instanceof_check);
instanceof_check(realmBArray);
assertOptimized(instanceof_check);

// Try to optimize again, but first clear all type feedback, and allow it
// to be monomorphic on first call. Only after optimizing do we introduce
// realmBArray. This should deopt the method.
  %PrepareFunctionForOptimization(instanceof_check);
  %DeoptimizeFunction(instanceof_check);
  %ClearFunctionFeedback(instanceof_check);
instanceof_check(Array);
instanceof_check(Array);
  %PrepareFunctionForOptimization(instanceof_check);
  %OptimizeFunctionOnNextCall(instanceof_check);
instanceof_check(Array);
assertOptimized(instanceof_check);

instanceof_check(realmBArray);
assertUnoptimized(instanceof_check);

// Perform a gc because without it the test below can experience an
// allocation failure at an inconvenient point. Allocation mementos get
// cleared on gc, and they can't deliver elements kind feedback when that
// happens.
gc();

// Case: make sure nested arrays benefit from allocation site feedback as
// well.
(function() {
  // Make sure we handle nested arrays
  function get_nested_literal() {
    var literal = [[1,2,3,4], [2], [3]];
    return literal;
  }

  obj = get_nested_literal();
  assertKind(elements_kind.fast, obj);
  obj[0][0] = 3.5;
  obj[2][0] = "hello";
  obj = get_nested_literal();
  assertKind(elements_kind.fast_double, obj[0]);
  assertKind(elements_kind.fast_smi_only, obj[1]);
  assertKind(elements_kind.fast, obj[2]);

  // A more complex nested literal case.
  function get_deep_nested_literal() {
    var literal = [[1], [[2], "hello"], 3, [4]];
    return literal;
  }

  obj = get_deep_nested_literal();
  assertKind(elements_kind.fast_smi_only, obj[1][0]);
  obj[0][0] = 3.5;
  obj[1][0][0] = "goodbye";
  assertKind(elements_kind.fast_double, obj[0]);
  assertKind(elements_kind.fast, obj[1][0]);

  obj = get_deep_nested_literal();
  assertKind(elements_kind.fast_double, obj[0]);
  assertKind(elements_kind.fast, obj[1][0]);
})();

// Perform a gc because without it the test below can experience an
// allocation failure at an inconvenient point. Allocation mementos get
// cleared on gc, and they can't deliver elements kind feedback when that
// happens.
gc();

// Make sure object literals with array fields benefit from the type feedback
// that allocation mementos provide.
(function() {
  // A literal in an object
  function get_object_literal() {
    var literal = {
      array: [1,2,3],
      data: 3.5
    };
    return literal;
  }

  obj = get_object_literal();
  assertKind(elements_kind.fast_smi_only, obj.array);
  // Force double transition.
  obj.array[1] = 3.5;
  assertKind(elements_kind.fast_double, obj.array);
  // Transition information should be fed back to the inner literal.
  obj = get_object_literal();
  assertKind(elements_kind.fast_double, obj.array);

  function get_nested_object_literal() {
    var literal = {
      array: [[1],[2],[3]],
      data: 3.5
    };
    return literal;
  }

  obj = get_nested_object_literal();
  assertKind(elements_kind.fast, obj.array);
  assertKind(elements_kind.fast_smi_only, obj.array[1]);
  obj.array[1][0] = 3.5;
  assertKind(elements_kind.fast_double, obj.array[1]);
  obj = get_nested_object_literal();
  assertKind(elements_kind.fast_double, obj.array[1]);

    %OptimizeFunctionOnNextCall(get_nested_object_literal);
  get_nested_object_literal();
  obj = get_nested_object_literal();
  assertKind(elements_kind.fast_double, obj.array[1]);

  // Make sure we handle nested arrays
  function get_nested_literal() {
    var literal = [[1,2,3,4], [2], [3]];
    return literal;
  }

  obj = get_nested_literal();
  assertKind(elements_kind.fast, obj);
  obj[0][0] = 3.5;
  obj[2][0] = "hello";
  obj = get_nested_literal();
  assertKind(elements_kind.fast_double, obj[0]);
  assertKind(elements_kind.fast_smi_only, obj[1]);
  assertKind(elements_kind.fast, obj[2]);

  // A more complex nested literal case.
  function get_deep_nested_literal() {
    var literal = [[1], [[2], "hello"], 3, [4]];
    return literal;
  }

  obj = get_deep_nested_literal();
  assertKind(elements_kind.fast_smi_only, obj[1][0]);
  obj[0][0] = 3.5;
  obj[1][0][0] = "goodbye";
  assertKind(elements_kind.fast_double, obj[0]);
  assertKind(elements_kind.fast, obj[1][0]);

  obj = get_deep_nested_literal();
  assertKind(elements_kind.fast_double, obj[0]);
  assertKind(elements_kind.fast, obj[1][0]);
})();

// Test gathering allocation site feedback for generic ics.
(function() {
  function make() { return new Array(); }
  function foo(a, i) { a[0] = i; }

  var a = make();
  assertKind(elements_kind.fast_smi_only, a);

  // Make the keyed store ic go generic.
  foo("howdy", 1);
  foo(a, 3.5);

  var b = make();
  assertKind(elements_kind.fast_double, b);
})();

(function TestBoilerplateMapDeprecation() {
  function literal() {
    return { a: 1, b: 2 };
  }
  literal();
  literal();
  let instance = literal();
  assertKind(elements_kind.fast_smi_only, [instance.a, instance.b]);
  // Create literal instances with double insteand of smi values.
  for (let i = 0; i < 1000; i++) {
    instance  = literal();
    instance.a = 1.2;
    assertKind(elements_kind.fast_double, [instance.a, instance.b]);
  }

  // After deprecating the original boilerplate map we should get heap numbers
  // back for the original unmodified literal as well.
  for (let i =0; i < 100; i++) {
    instance = literal();
    assertKind(elements_kind.fast_double, [instance.a, instance.b]);
  }
})();

(function TestInnerBoilerplateMapDeprecation() {
  // Create a literal where the inner literals cause a map deprecation of the
  // previous inner literal.
  function literal() {
    return [
    {xA2A:false, a: 1,   b: 2, c: 3, d: 4.1},
    {xA2A:false, a: 1,   b: 2, c: 3, d: 4.1},
    {xA2A:false, a: 1,   b: 2, c: 3, d: 4.1},
    {xA2A:false, a: 1,   b: 2, c: 3, d: 4.1},

    {xA2A:false, a: 1.1, b: 2, c: 3, d: 4.1},
    {xA2A:false, a: 1.1, b: 2, c: 3, d: 4.1},
    {xA2A:false, a: 1.1, b: 2, c: 3, d: 4.1},
    {xA2A:false, a: 1.1, b: 2, c: 3, d: 4.1},
    {xA2A:false, a: 1.1, b: 2, c: 3, d: 4.1},
    {xA2A:false, a: 1.1, b: 2, c: 3, d: 4.1},
    {xA2A:false, a: 1.1, b: 2, c: 3, d: 4.1},
    {xA2A:false, a: 1.1, b: 2, c: 3, d: 4.1},
    {xA2A:false, a: 1.1, b: 2, c: 3, d: 4.1},
    {xA2A:false, a: 1.1, b: 2, c: 3, d: 4.1}
    ];
  };
  let instance = literal();

  // Make sure all sub-literals are migrated properly.
  for (let i = 0; i < instance.length; i++) {
    let sub_literal = instance[i];
    assertKind(elements_kind.fast_double, [sub_literal.a]);
    assertKind(elements_kind.fast_smi_only, [sub_literal.b]);
    assertKind(elements_kind.fast_smi_only, [sub_literal.c]);
    assertKind(elements_kind.fast_double, [sub_literal.d]);
  }

  instance = literal();
  instance = literal();
  instance = literal();
  for (let i = 0; i < instance.length; i++) {
    let sub_literal = instance[i];
    assertKind(elements_kind.fast_double, [sub_literal.a]);
    assertKind(elements_kind.fast_smi_only, [sub_literal.b]);
    assertKind(elements_kind.fast_smi_only, [sub_literal.c]);
    assertKind(elements_kind.fast_double, [sub_literal.d]);
  }
})();