[jboss-jira] [JBoss JIRA] Created: (JASSIST-80) Editing MethodCall produces incorrect byte code | java.lang.VerifyError: Illegal target of jump or branch | invalid instruction

[Martin Burger (JIRA)]

Editing MethodCall produces incorrect byte code | java.lang.VerifyError: Illegal target of jump or branch | invalid instruction
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                 Key: JASSIST-80
                 URL: https://jira.jboss.org/jira/browse/JASSIST-80
             Project: Javassist
          Issue Type: Bug
    Affects Versions: 3.10.0.GA
         Environment: $ java -version
java version "1.6.0_07"
Java(TM) SE Runtime Environment (build 1.6.0_07-b06-153)
Java HotSpot(TM) 64-Bit Server VM (build 1.6.0_07-b06-57, mixed mode) 
            Reporter: Martin Burger
            Assignee: Shigeru Chiba


Note: Most likely this issue is related to JASSIST-79.

I instrument method calls in a class called org.mozilla.javascript.TokenStream.

If I run (or, load) this class, a java.lang.VerifyError will be thrown:

Exception in thread "main" java.lang.VerifyError: (class: org/mozilla/javascript/TokenStream, method: getToken$JINSI_4etOXffNDXVw signature: ()I) Illegal target of jump or branch

It seems Javassist introduces a defective goto statement at position 33217 in method getToken$JINSI_4etOXffNDXVw:

33217	goto	465

The corresponding Java code (excerpt):

            case '-':
                if (matchChar('=')) {
                    this.op = SUB;
                    c = ASSIGN;
                } else if (matchChar('-')) {
                    if (0 == (flags & TSF_DIRTYLINE)) {
                        // treat HTML end-comment after possible whitespace
                        // after line start as comment-utill-eol
                        if (matchChar('>')) {
                            skipLine();
                            continue retry;
                        }
                    }
                    c = DEC;
                } else {
                    c = SUB;
                }
                flags |= TSF_DIRTYLINE;
                return c;

I think the continue statement is related to this defect.

JAD fails to decompile the instrumented class:

ERROR: invalid instruction at 33217 in the method getToken$JINSI_4etOXffNDXVw. The method will be decompiled incorrectly.

Javassist's framedump fails, too:

Exception in thread "main" java.lang.RuntimeException: javassist.bytecode.BadBytecode: Stack is empty[pos = 465]
        at javassist.bytecode.analysis.FramePrinter.print(FramePrinter.java:89)
        at javassist.bytecode.analysis.FramePrinter.print(FramePrinter.java:60)
        at javassist.bytecode.analysis.FramePrinter.print(FramePrinter.java:51)
        at javassist.tools.framedump.main(framedump.java:45)
Caused by: javassist.bytecode.BadBytecode: Stack is empty[pos = 465]
        at javassist.bytecode.analysis.Analyzer.analyzeNextEntry(Analyzer.java:179)
        at javassist.bytecode.analysis.Analyzer.analyze(Analyzer.java:143)
        at javassist.bytecode.analysis.FramePrinter.print(FramePrinter.java:87)
        ... 3 more
Caused by: java.lang.IndexOutOfBoundsException: Stack is empty
        at javassist.bytecode.analysis.Frame.pop(Frame.java:130)
        at javassist.bytecode.analysis.Executor.simplePop(Executor.java:970)
        at javassist.bytecode.analysis.Executor.evalStore(Executor.java:869)
        at javassist.bytecode.analysis.Executor.execute(Executor.java:188)
        at javassist.bytecode.analysis.Analyzer.analyzeNextEntry(Analyzer.java:177)
        ... 5 more

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