v8/test/mjsunit/compiler/string-startswith.js
Maya Lekova 4e6aa9767a [turbofan] Fix startsWith when no search term is passed
This CL fixes the behaviour of String.prototype.startsWith when
undefined is passed as the search term. It also implements a small
shorthand when the search term is empty (according to the spec).

Bug: v8:11977
Change-Id: Iec2aa5f4301fcf444f20d5c1a80d3f634624d6f3
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3035089
Commit-Queue: Maya Lekova <mslekova@chromium.org>
Commit-Queue: Georg Neis <neis@chromium.org>
Auto-Submit: Maya Lekova <mslekova@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#75763}
2021-07-16 14:10:42 +00:00

95 lines
2.3 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
(function() {
function foo(string) { return string.startsWith('a'); }
%PrepareFunctionForOptimization(foo);
assertEquals(false, foo(''));
assertEquals(true, foo('a'));
assertEquals(false, foo('ba'));
assertEquals(true, foo('abc'));
%OptimizeFunctionOnNextCall(foo);
assertEquals(false, foo(''));
assertEquals(true, foo('a'));
assertEquals(false, foo('ba'));
assertEquals(true, foo('abc'));
assertOptimized(foo);
})();
(function() {
function f() { return "abc".startsWith(); }
%PrepareFunctionForOptimization(f);
assertEquals(false, f());
assertEquals(false, f());
%OptimizeFunctionOnNextCall(f);
assertEquals(false, f());
assertOptimized(f);
})();
(function() {
function g(n) { return "abc".startsWith("a", n); }
%PrepareFunctionForOptimization(g);
assertEquals(true, g(-1));
assertEquals(true, g(0));
assertEquals(false, g(1));
assertEquals(false, g(2));
assertEquals(false, g(3));
assertEquals(false, g(4));
%OptimizeFunctionOnNextCall(g);
assertEquals(true, g(-1));
assertEquals(true, g(0));
assertEquals(false, g(1));
assertEquals(false, g(2));
assertEquals(false, g(3));
assertEquals(false, g(4));
assertOptimized(g);
})();
(function() {
function g(n) { return "cba".startsWith("a", n); }
%PrepareFunctionForOptimization(g);
assertEquals(false, g(-1));
assertEquals(false, g(0));
assertEquals(false, g(1));
assertEquals(true, g(2));
assertEquals(false, g(3));
assertEquals(false, g(4));
%OptimizeFunctionOnNextCall(g);
assertEquals(false, g(-1));
assertEquals(false, g(0));
assertEquals(false, g(1));
assertEquals(true, g(2));
assertEquals(false, g(3));
assertEquals(false, g(4));
assertOptimized(g);
})();
(function() {
function f(n) { return "cba".startsWith("a", n); }
%PrepareFunctionForOptimization(f);
f();
f();
%OptimizeFunctionOnNextCall(f);
assertEquals(false, f(1073741824));
})();
(function() {
function f(str) {
return str.startsWith('');
}
%PrepareFunctionForOptimization(f);
f('foo');
f('');
%OptimizeFunctionOnNextCall(f);
assertEquals(f('foo'), true);
assertEquals(f(''), true);
})();