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https://issues.apache.org/jira/browse/BCEL-283?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Mark Roberts updated BCEL-283:
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Attachment: Appendix1-verifier.pdf
ClassFileCMP-SE6.0.pdf
> Support for StackMap should be different from StackMapTable
> -----------------------------------------------------------
>
> Key: BCEL-283
> URL: https://issues.apache.org/jira/browse/BCEL-283
> Project: Commons BCEL
> Issue Type: Bug
> Reporter: Mark Roberts
> Attachments: Appendix1-verifier.pdf, ClassFileCMP-SE6.0.pdf
>
>
> It turns out we made a mistake with the StackMap renaming changes. I ran
> into a problem decoding some old .class files and went back to the Java
> Specification Requests (JSRs) to try and understand the history of the
> StackMap attribute. While I was not able to get the complete story, I have a
> pretty good guess at what happened and it does explain the problem I have
> seen.
> The official introduction of StackMaps appears to be JSR 202 from (approx.)
> Sept. 2006 and it is part of JDK6 (see attached spec) . However, StackMaps
> were originally proposed much earlier (approx.) March 2002 - see the attached
> verifier spec. It appears there were some implementations of this earlier
> specification - the ASM tool was one and there may be others.
> The key differences are:
> Typechecker Spec: StackMap attribute with fixed format and no frame type
> byte
> JDK 6 Spec: StackMapTable attribute with variable format including
> a frame type byte.
> The JVM and the javap tool support BOTH formats. BCEL recognizes both
> attribute names, but treats them the same, as JDK6 version.
> I don't think the changes will be too difficult. I will create a proposed
> fix within the next few days.
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