v8/test/mjsunit/maglev/lazy-deopt-with-onstack-activation.js
Leszek Swirski 0df9606dca [maglev] Add lazy deopts
Nodes can now hold a LazyDeoptSafepoint which stores the frame state in
case they trigger a lazy deopt. OpProperties have a new CanLazyDeopt
bit, and codegen emits a safepoint table entry + lazy deopt for all
nodes with this bit. Also, we now check the deoptimized code bit on
entry into the maglev compiled function.

An example use of these lazy deopts is added as a PropertyCell fast path
for LdaGlobal, which adds a code dependency on the property cell.

Bug: v8:7700
Change-Id: I663db38dfa7325d38fc6d5f079d263a958074e36
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3557251
Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Reviewed-by: Jakob Linke <jgruber@chromium.org>
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/main@{#79688}
2022-03-31 11:48:40 +00:00

34 lines
658 B
JavaScript

// Copyright 2022 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 --maglev --no-always-opt
var x = 1;
var do_change = false;
function g() {
if (do_change) {
x = 2;
return 40;
}
return 30;
}
function f() {
return g() + x;
}
%PrepareFunctionForOptimization(f);
assertEquals(31, f());
%OptimizeMaglevOnNextCall(f);
assertEquals(31, f());
assertTrue(isMaglevved(f));
// Trigger a lazy deopt on the next g() call.
do_change = true;
assertEquals(42, f());
assertFalse(isMaglevved(f));
assertUnoptimized(f);