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https://issues.apache.org/jira/browse/BCEL-195?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14711977#comment-14711977
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Sebb commented on BCEL-195:
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OK, I see.
Do both patches need to be applied still?
But we really need some test code that can potentially expose the problem and
test the new code.
I realise that it's not possible to provide a copy of everything Daikon does,
but even a single sample would help.
Seems to me that there are at least two types of branch changes:
- changing one or more branch instructions to point to a new location
- changing the position of an Instruction handle within the list by
adding/removing instructions earlier in the list
I assume it is the first case that is causing problems.
> addition of hashCode() to generic/Instruction.java breaks Targeters
> -------------------------------------------------------------------
>
> Key: BCEL-195
> URL: https://issues.apache.org/jira/browse/BCEL-195
> Project: Commons BCEL
> Issue Type: Bug
> Components: Main
> Affects Versions: 6.0
> Reporter: Mark Roberts
> Attachments: bcel195.diff, targeters.diff
>
>
> [Revision 1532198|http://svn.apache.org/r1532198] added a {{hashCode()}}
> function to the Instruction class. Unfortunately, this breaks the
> Instruction targeting mechanism. I understand the goal of trying to reuse
> instructions - an 'iadd' is the same as any other 'iadd'. However, one
> 'goto 50' is not the same as another 'goto 50' due to the way Targeters are
> implemented. If branch instructions are reused, then only one entry gets put
> on the Targeter list. So when some api is used to modify the instruction
> list and location 50 becomes location 52 ONLY ONE of the branches gets
> updated. A very bad thing. So unless you modify the hash to special case
> branch instructions (and there might be other instructions needing special
> treatment as well) its broken. We fixed it by simply commenting the hash out
> to make things like they used to be and all works great.
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