FoldVerifier.java

/*
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 * 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.
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package org.graalvm.compiler.replacements.verifier;

import java.lang.annotation.Annotation;

import javax.annotation.processing.ProcessingEnvironment;
import javax.lang.model.element.AnnotationMirror;
import javax.lang.model.element.Element;
import javax.lang.model.element.ElementKind;
import javax.lang.model.element.ExecutableElement;
import javax.lang.model.element.Modifier;
import javax.lang.model.type.TypeKind;
import javax.tools.Diagnostic.Kind;

import org.graalvm.compiler.api.replacements.Fold;

public final class FoldVerifier extends AbstractVerifier {

    public FoldVerifier(ProcessingEnvironment env) {
        super(env);
    }

    @Override
    public Class<? extends Annotation> getAnnotationClass() {
        return Fold.class;
    }

    @Override
    public void verify(Element element, AnnotationMirror annotation, PluginGenerator generator) {
        if (element.getKind() != ElementKind.METHOD) {
            assert false : "Element is guaranteed to be a method.";
            return;
        }

        ExecutableElement foldMethod = (ExecutableElement) element;
        if (foldMethod.getReturnType().getKind() == TypeKind.VOID) {
            env.getMessager().printMessage(Kind.ERROR,
                            String.format("A @%s method must not be void as it won't yield a compile-time constant (the reason for supporting folding!).", Fold.class.getSimpleName()), element,
                            annotation);
        } else if (foldMethod.getModifiers().contains(Modifier.PRIVATE)) {
            env.getMessager().printMessage(Kind.ERROR, String.format("A @%s method must not be private.", Fold.class.getSimpleName()), element, annotation);
        } else {
            generator.addPlugin(new GeneratedFoldPlugin(foldMethod));
        }
    }
}