52 lines
1.4 KiB
JavaScript
52 lines
1.4 KiB
JavaScript
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// Copyright 2019 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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// The GetIterator bytecode is used to implement a part of the iterator
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// protocol (https://tc39.es/ecma262/#sec-getiterator).
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// Here, call to the @@iterator property returns invalid JS receiver.
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// This test ensures that the optimized version of the GetIterator bytecode
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// incorporates exception handling mechanism without deoptimizing.
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// Flags: --allow-natives-syntax --opt
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var iteratorCount = 0;
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var exceptionCount = 0;
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function foo(obj) {
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// The following for-of loop uses the iterator protocol to iterate
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// over the 'obj'.
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// The GetIterator bytecode invovlves 3 steps:
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// 1. method = GetMethod(obj, @@iterator)
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// 2. iterator = Call(method, obj)
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// 3. if(!IsJSReceiver(iterator)) throw SymbolIteratorInvalid.
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try{
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for(let a of obj){
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assertUnreachable();
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}
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} catch(e){
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exceptionCount++;
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}
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}
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// This iterator retuns '3' which is not a valid JSReceiver
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var iterator = function() {
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iteratorCount++;
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return 3;
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}
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let y = {
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get [Symbol.iterator]() {
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return iterator;
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}
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};
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%PrepareFunctionForOptimization(foo);
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foo(y);
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foo(y);
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%OptimizeFunctionOnNextCall(foo);
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foo(y);
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assertOptimized(foo);
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assertEquals(iteratorCount, 3);
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assertEquals(exceptionCount, 3);
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