Re: ClassReader exception due to bad bytecode

Hi Buu,

org.objectweb.asm.util.CheckClassAdapter is your friend. It has a more
verbose output of failure reasons in your instrumented code.

Best regards

Tronje

Buu Vinh wrote:
> After using ASM 3.2 for the bytecode instrumentation, I tried to verify the result by feeding the transformed bytecode to ClassReader and invoking ASMifierClassVisitor:
> .........
> cr = new ClassReader(originalBytes);
> cw = new ClassWriter(cr,ClassWriter.COMPUTE_MAXS);
> BciClassAdapter bca = new BciClassAdapter(cw, iClass);
> cr.accept(bca, 0);
> byte[] newBytes = cw.toByteArray();
> 
> ClassReader cr = new ClassReader(newBytes);  
> File tmpFile = new File(fileName);
> File tmpDir = tmpFile.getParentFile();
> tmpDir.mkdirs();
> ClassVisitor cv = new ASMifierClassVisitor(new PrintWriter(tmpFile));
> cr.accept(cv, 0);
> ........
> 
> I got ClassReader Exception when processing "newBytes":
> 
> java.lang.ArrayIndexOutOfBoundsException: Array index out of range: 51966   
>  at com.bv.asm.ClassReader.readUTF8(ClassReader.java:1946)                 
>  at com.bv.asm.ClassReader.readClass(ClassReader.java:2015)                
>  at com.bv.asm.ClassReader.getClassName(ClassReader.java:229)              
>  at com.bv.bci.instrument.InstrumentClass.verify(InstrumentClass.java:287) 
> 
> Apparently ClassReader was not able to parse "newBytes", I assumed that "newBytes" was ill-formated due to some kind of problem in my bytecode instrumenation, but I could not locate the error. I used ClassWriter.COMPUTE_MAXS, but it did not help. Please advice. Thanks
> 
> 
> 

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     Tronje Krop <[email protected]>

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