e71b802279
The existing object materialization in the deoptimizer has the following problems: - Objects do not necessarily verify during materialization (because during the depth first walk we might have inconsistent objects). - Stack can overflow (because we just materialize using recursive calls). - We generalize object fields. This CL re-implements the materialization algorithm to solve this problem. The new implementation creates the objects in two steps: 1. We allocate space for all the objects. In general, we allocate ByteArrays of the right size. For leaf objects that cannot participate in cycles, we build and initialize the materialized objects completely. For JS objects, we insert markers into the byte array at the positions where unboxed doubles are expected. 2. We initialize all the objects with the proper field values and change the map from the ByteArray map to the correct map. This requires some sync with the concurrent marker (Heap::NotifyObjectLayoutChange). When initializing the JS object fields, we make sure that we respect the unboxed double marker. Bug: chromium:770106, v8:3836 Change-Id: I1ec466a9d19db9538df4ba915516d4c3ca825632 Reviewed-on: https://chromium-review.googlesource.com/777559 Commit-Queue: Jaroslav Sevcik <jarin@chromium.org> Reviewed-by: Ulan Degenbaev <ulan@chromium.org> Reviewed-by: Michael Starzinger <mstarzinger@chromium.org> Cr-Commit-Position: refs/heads/master@{#49821}
23 lines
496 B
JavaScript
23 lines
496 B
JavaScript
// Copyright 2017 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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// Flags: --allow-natives-syntax
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function C() {}
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%CompleteInobjectSlackTracking(new C());
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function f() {
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// Create a non-escaping object.
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var o = new C();
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// Add an out-of-object double property.
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o.x = 0.5;
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%DeoptimizeNow();
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return o.x + 0.25;
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}
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f();
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f();
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%OptimizeFunctionOnNextCall(f);
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assertEquals(0.75, f());
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