jdk-24/test/langtools/tools/javac/patterns/NoUnnecessaryCast.java

110 lines
4.3 KiB
Java

/*
* Copyright (c) 2020, 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.
* @modules jdk.jdeps/com.sun.tools.classfile
* @compile NoUnnecessaryCast.java
* @run main NoUnnecessaryCast
*/
import java.io.File;
import java.io.IOException;
import com.sun.tools.classfile.Attribute;
import com.sun.tools.classfile.ClassFile;
import com.sun.tools.classfile.Code_attribute;
import com.sun.tools.classfile.Code_attribute.InvalidIndex;
import com.sun.tools.classfile.ConstantPool;
import com.sun.tools.classfile.ConstantPoolException;
import com.sun.tools.classfile.Descriptor.InvalidDescriptor;
import com.sun.tools.classfile.Instruction;
import com.sun.tools.classfile.Method;
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, ConstantPoolException, InvalidDescriptor, InvalidIndex {
new NoUnnecessaryCast()
.checkClassFile(new File(System.getProperty("test.classes", "."),
NoUnnecessaryCast.class.getName() + ".class"));
}
void checkClassFile(File file)
throws IOException, ConstantPoolException, InvalidDescriptor, InvalidIndex {
ClassFile classFile = ClassFile.read(file);
ConstantPool constantPool = classFile.constant_pool;
Method method = Arrays.stream(classFile.methods)
.filter(m -> getName(m, constantPool)
.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
""";
Code_attribute code = (Code_attribute) method.attributes
.get(Attribute.Code);
String actualInstructions = printCode(code);
if (!expectedInstructions.equals(actualInstructions)) {
throw new AssertionError("Unexpected instructions found:\n" +
actualInstructions);
}
}
String printCode(Code_attribute code) {
return StreamSupport.stream(code.getInstructions().spliterator(), false)
.map(Instruction::getMnemonic)
.collect(Collectors.joining("\n", "", "\n"));
}
String getName(Method m, ConstantPool constantPool) {
try {
return m.getName(constantPool);
} catch (ConstantPoolException ex) {
throw new IllegalStateException(ex);
}
}
boolean test(Object o) {
return o instanceof String s && s.isEmpty();
}
}