v8/test/mjsunit/compiler/regress-9945-1.js
Georg Neis 52e07ffec5 [turbofan] Fix a deopt loop
... by disallowing checkpoint elimination across function boundaries.
See the comment in checkpoint-elimination.cc and the tests for details.

Bug: v8:9945
Change-Id: Ibf4ab6f0e4e709e26d3c4428a082ef45dcbeb8b0
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1906208
Auto-Submit: Georg Neis <neis@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Maya Lekova <mslekova@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Commit-Queue: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#65027}
2019-11-19 08:18:37 +00:00

67 lines
1.9 KiB
JavaScript

// Copyright 2019 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// Flags: --allow-natives-syntax --opt --no-always-opt
// Flags: --concurrent-recompilation --block-concurrent-recompilation
function foo(x) { bar(x) }
function bar(x) { x.p }
%PrepareFunctionForOptimization(foo);
%PrepareFunctionForOptimization(bar);
// Create map transitions such that a's final map is not stable.
var dummy = [];
dummy.p = 0;
dummy.q = 0;
var a = [];
a.p = 42;
var b = [];
b.p = 42;
// Warm-up.
foo(a);
foo(a);
// Trigger optimization of bar but don't yet complete it.
%OptimizeFunctionOnNextCall(bar, "concurrent");
foo(a);
%PrepareFunctionForOptimization(bar);
// Change a's map from PACKED_SMI_ELEMENTS to PACKED_ELEMENTS and run bar in the
// interpreter (via foo) s.t. bar's load feedback changes accordingly.
a[0] = {};
foo(a);
assertUnoptimized(bar, "no sync");
// Now finish the optimization of bar, which was based on the old
// PACKED_SMI_ELEMENTS feedback.
%UnblockConcurrentRecompilation();
assertOptimized(bar);
// If we were to call the optimized bar now, it would deopt.
// Instead we trigger optimization of foo, which will inline bar (this time
// based on the new PACKED_ELEMENTS map.
%OptimizeFunctionOnNextCall(foo);
foo(a);
assertOptimized(foo);
%PrepareFunctionForOptimization(foo);
assertOptimized(bar);
// Now call the optimized foo on an object that has the old PACKED_SMI_ELEMENTS
// map. This will lead to an eager deopt of foo when the inlined bar sees that
// old map.
foo(b);
assertUnoptimized(foo);
assertOptimized(bar);
// Now ensure there is no deopt-loop. There used to be a deopt-loop because, as
// a result of over-eager checkpoint elimination, we used to deopt into foo
// (right before the call to bar) rather than into bar (right before the load).
%OptimizeFunctionOnNextCall(foo);
foo(b);
assertOptimized(foo);