b6f7ea5805
As discussed in https://docs.google.com/document/d/1sBdGe8RHgeYP850cKSSgGABTyfMdvaEWLy-vertuTCo/edit?ts=5b3ba5cc#, this CL introduces a new bytecode (CloneObject), and a new IC type. In this prototype implementation, the type feedback looks like the following: Uninitialized case: { uninitialized_sentinel, uninitialized_sentinel } Monomorphic case: { weak 'source' map, strong 'result' map } Polymorphic case: { WeakFixedArray with { weak 'source' map, strong 'result' map }, cleared value } Megamorphic case: { megamorphic_sentinel, cleared_Value } In the fast case, Object cloning is done by allocating an object with the saved result map, and a shallow clone of the fast properties from the source object, as well as cloned fast elements from the source object. If at any point the fast case can't be taken, the IC transitions to the slow case and remains there. This prototype CL does not include any TurboFan optimization, and the CloneObject operation is merely reduced to a stub call. It may still be possible to get some further improvements by somehow incorporating compile-time boilerplate elements into the cloned object, or simplifying how the boilerplate elements are inserted into the object. In terms of performance, we improve the ObjectSpread score in JSTests/ObjectLiteralSpread/ by about 8x, with substantial improvements over the Babel and ObjectAssign scores. R=gsathya@chromium.org, mvstanton@chromium.org, rmcilroy@chromium.org, neis@chromium.org, bmeurer@chromium.org BUG=v8:7611 Change-Id: I79e1796eb77016fb4feba0e1d3bb9abb348c183e Reviewed-on: https://chromium-review.googlesource.com/1127472 Commit-Queue: Caitlin Potter <caitp@igalia.com> Reviewed-by: Ross McIlroy <rmcilroy@chromium.org> Reviewed-by: Michael Stanton <mvstanton@chromium.org> Reviewed-by: Georg Neis <neis@chromium.org> Reviewed-by: Jakob Kummerow <jkummerow@chromium.org> Cr-Commit-Position: refs/heads/master@{#54595}
102 lines
2.3 KiB
JavaScript
102 lines
2.3 KiB
JavaScript
// Copyright 2018 the V8 project authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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(function testDoubleElements() {
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function f(src) { return {...src}; }
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var src = [1.5];
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src[0] = 1;
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// Uninitialized
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assertEquals({ 0: 1 }, f(src));
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src[0] = 1.3;
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// Monomorphic
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assertEquals({ 0: 1.3 }, f(src));
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})();
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(function testInObjectProperties() {
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function f(src) { return {...src}; }
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function C() { this.foo = "foo"; }
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var src;
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for (var i = 0; i < 10; ++i) {
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src = new C();
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}
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// Uninitialized
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assertEquals({ foo: "foo" }, f(src));
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// Monomorphic
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assertEquals({ foo: "foo" }, f(src));
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})();
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(function testInObjectProperties2() {
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function f(src) { return {...src}; }
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function C() {
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this.foo = "foo";
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this.p0 = "0";
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this.p1 = "1";
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this.p2 = "2";
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this.p3 = "3";
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}
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var src;
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for (var i = 0; i < 10; ++i) {
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src = new C();
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}
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// Uninitialized
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assertEquals({ foo: "foo", p0: "0", p1: "1", p2: "2", p3: "3" }, f(src));
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// Monomorphic
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assertEquals({ foo: "foo", p0: "0", p1: "1", p2: "2", p3: "3" }, f(src));
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})();
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(function testPolymorphicToMegamorphic() {
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function f(src) { return {...src}; }
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function C1() {
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this.foo = "foo";
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this.p0 = "0";
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this.p1 = "1";
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this.p2 = "2";
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this.p3 = "3";
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}
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function C2() {
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this.p0 = "0";
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this.p1 = "1";
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this[0] = 0;
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}
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function C3() {
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this.x = 774;
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this.y = 663;
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this.rgb = 0xFF00FF;
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}
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function C4() {
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this.qqq = {};
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this.v_1 = [];
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this.name = "C4";
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this.constructor = C4;
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}
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// Uninitialized
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assertEquals({ foo: "foo", p0: "0", p1: "1", p2: "2", p3: "3" }, f(new C1()));
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// Monomorphic
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assertEquals({ foo: "foo", p0: "0", p1: "1", p2: "2", p3: "3" }, f(new C1()));
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// Polymorphic (2)
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assertEquals({ 0: 0, p0: "0", p1: "1" }, f(new C2()));
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assertEquals({ 0: 0, p0: "0", p1: "1" }, f(new C2()));
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// Polymorphic (3)
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assertEquals({ x: 774, y: 663, rgb: 0xFF00FF }, f(new C3()));
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assertEquals({ x: 774, y: 663, rgb: 0xFF00FF }, f(new C3()));
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// Polymorphic (4)
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assertEquals({ qqq: {}, v_1: [], name: "C4", constructor: C4 }, f(new C4()));
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assertEquals({ qqq: {}, v_1: [], name: "C4", constructor: C4 }, f(new C4()));
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// Megamorphic
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assertEquals({ boop: 1 }, f({ boop: 1 }));
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})();
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