jdk-24/test/jdk/java/lang/StackWalker/TestBCI.java

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * This code is free software; you can redistribute it and/or modify it
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 *
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 * 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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 */

/*
 * @test
 * @bug 8140450
 * @summary Basic test for the StackWalker::getByteCodeIndex method
 * @enablePreview
 * @run main TestBCI
 */

import java.lang.StackWalker.StackFrame;
import java.io.IOException;
import java.io.InputStream;
import java.lang.classfile.Attributes;
import java.lang.classfile.ClassFile;
import java.lang.classfile.ClassModel;
import java.lang.classfile.MethodModel;
import java.lang.constant.MethodTypeDesc;
import java.util.Comparator;
import java.util.HashMap;
import java.util.Map;
import java.util.Optional;
import java.util.SortedSet;
import java.util.TreeSet;
import java.util.function.Function;
import java.util.stream.Collectors;

import static java.lang.StackWalker.Option.RETAIN_CLASS_REFERENCE;

public class TestBCI {
    public static void main(String... args) throws Exception {
        TestBCI test = new TestBCI(Walker.class);
        System.out.println("Line number table:");
        test.methods.values().stream()
            .sorted(Comparator.comparing(MethodInfo::name).reversed())
            .forEach(System.out::println);

        // walk the stack
        test.walk();
    }

    private final Map<String, MethodInfo> methods;
    private final Class<?> clazz;
    TestBCI(Class<?> c) throws IllegalArgumentException, IOException {
        Map<String, MethodInfo> methods;
        String filename = c.getName().replace('.', '/') + ".class";
        try (InputStream in = c.getResourceAsStream(filename)) {
            var cf = ClassFile.of().parse(in.readAllBytes());
            methods = cf.methods().stream()
                .map(m -> new MethodInfo(cf, m))
                .collect(Collectors.toMap(MethodInfo::name, Function.identity()));
        }
        this.clazz = c;
        this.methods = methods;
    }

    void walk() {
        Walker walker = new Walker();
        walker.m1();
    }

    void verify(StackFrame frame) {
        if (frame.getDeclaringClass() != clazz)
            return;

        int bci = frame.getByteCodeIndex();
        int lineNumber = frame.getLineNumber();
        System.out.format("%s.%s bci %d (%s:%d)%n",
                          frame.getClassName(), frame.getMethodName(), bci,
                          frame.getFileName(), lineNumber);

        MethodInfo method = methods.get(frame.getMethodName());
        SortedSet<Integer> values = method.findLineNumbers(bci).get();
        if (!values.contains(lineNumber)) {
            throw new RuntimeException("line number for bci: " + bci + " "
                + lineNumber + " not matched line number table: " + values);
        }
    }

    /*
     * BCIs in the execution stack when StackWalker::forEach is invoked
     * will cover BCI range in the line number table.
     */
    class Walker {
        final StackWalker walker = StackWalker.getInstance(RETAIN_CLASS_REFERENCE);
        void m1() {
            int i = (int)Math.random()+2;
            m2(i*2);
        }

        void m2(int i) {
            i++;
            m3(i);
        }

        void m3(int i) {
            i++; m4(i++);
        }

        int m4(int i) {
            walker.forEach(TestBCI.this::verify);
            return i;
        }
    }

    static class MethodInfo {
        final MethodModel method;
        final String name;
        final MethodTypeDesc desc;
        final Map<Integer, SortedSet<Integer>> bciToLineNumbers = new HashMap<>();
        MethodInfo(ClassModel cf, MethodModel m) {
            this.method = m;
            this.name = m.methodName().stringValue();
            this.desc = m.methodTypeSymbol();
            m.code().orElseThrow(() -> new IllegalArgumentException("Missing Code in " + m))
                    .findAttribute(Attributes.lineNumberTable())
                    .orElseThrow(() -> new IllegalArgumentException("Missing LineNumberTable in " + m))
                    .lineNumbers().forEach(entry ->
                            bciToLineNumbers.computeIfAbsent(entry.startPc(), _ -> new TreeSet<>())
                                    .add(entry.lineNumber()));
        }

        String name() {
            return name;
        }

        Optional<SortedSet<Integer>> findLineNumbers(int value) {
            return bciToLineNumbers.entrySet().stream()
                    .sorted(Map.Entry.comparingByKey(Comparator.reverseOrder()))
                    .filter(e -> e.getKey().intValue() <= value)
                    .map(Map.Entry::getValue)
                    .findFirst();
        }

        @Override
        public String toString() {
            StringBuilder sb = new StringBuilder();
            sb.append(name);
            sb.append(desc.displayDescriptor()).append(" ");
            bciToLineNumbers.entrySet().stream()
                .sorted(Map.Entry.comparingByKey())
                .forEach(entry -> sb.append("bci:").append(entry.getKey()).append(" ")
                                    .append(entry.getValue()).append(" "));
            return sb.toString();
        }
    }

}