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/*
* Copyright (c) 2020, 2024, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
/*
* @test
* @bug 8237528
* @summary Verify there are no unnecessary checkcasts and conditions generated
* for the pattern matching in instanceof.
* @compile NoUnnecessaryCast.java
* @run main NoUnnecessaryCast
*/
import java.lang.classfile.*;
import java.lang.classfile.attribute.CodeAttribute;
import java.lang.classfile.constantpool.ConstantPool;
import java.io.File;
import java.io.IOException;
import java.util.Arrays;
import java.util.stream.Collectors;
import java.util.stream.StreamSupport;
public class NoUnnecessaryCast {
public static void main(String[] args) throws IOException {
new NoUnnecessaryCast()
.checkClassFile(new File(System.getProperty("test.classes", "."),
NoUnnecessaryCast.class.getName() + ".class"));
}
void checkClassFile(File file) throws IOException {
ClassModel classFile = ClassFile.of().parse(file.toPath());
MethodModel method = classFile.methods().stream()
.filter(m -> getName(m).equals("test"))
.findAny()
.get();
String expectedInstructions = """
ALOAD_1
INSTANCEOF
IFEQ
ALOAD_1
CHECKCAST
ASTORE_2
ALOAD_2
INVOKEVIRTUAL
IFEQ
ICONST_1
GOTO
ICONST_0
IRETURN
""";
CodeAttribute code = method.findAttribute(Attributes.code()).orElseThrow();
String actualInstructions = printCode(code);
if (!expectedInstructions.equals(actualInstructions)) {
throw new AssertionError("Unexpected instructions found:\n" +
actualInstructions);
}
}
String printCode(CodeAttribute code) {
return code.elementList().stream()
.filter(e -> e instanceof Instruction)
.map(ins -> ((Instruction) ins).opcode().name())
.collect(Collectors.joining("\n", "", "\n"));
}
String getName(MethodModel m) {
return m.methodName().stringValue();
}
boolean test(Object o) {
return o instanceof String s && s.isEmpty();
}
}
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