Re: [DynInst_API:] Inserting multiple snippets at an insertion point?

["Wayne Motycka" <wmotycka@xxxxxxxxxxx>]

Oh, I had forgot about the insertBefore and insertAfter flags, that is
probably what I'll need to use.

Thanks Bill.

-Wayne

On Mon, July 21, 2014 11:53 am, Bill Williams wrote:
> On 07/21/2014 11:45 AM, Wayne Motycka wrote:
>
>> I've been trying to find ways to instrument the edges in the Dyninst
>> CFG
>> but instrumenting the back edge from a system library call, e.g. calling
>>  printf(), doesn't give insertion points that seem reasonable/valid
>> (the
>> insertion point addresses given by getExitPoints() and getAllPoints()
>> appears to be out of the local programs address ranges.)
>>
> It's possible (and if memory serves, it's likely) that when you're
> inserting edge instrumentation, its instpoint address will be somewhere in
> relocated code and will not correspond neatly to an original address.
> (This is particularly true for call/return edges, as a particular
> interprocedural edge doesn't live anywhere in the original binary.) We
> *should* hand back NULL instpoints if they're really unusable.
>
>
>> So, I'm thinking of moving that edge instrumenting code block into the
>> edge that connects the calling block to the subsequent block along with
>> the instrumenting code for that connecting edge, effectively marking
>> that connecting edge as both the return path from the printf() system
>> call and the inter-block connecting edge (which is EdgeTypeEnum type of
>> "post-call
>> fallthrough")
>>
> This is also a reasonable approach, and call fallthrough edges exist for
> this sort of simplification.
>
>> My question is if it is possible to insert two snippets referencing
>> calls to my edge marking library routine?
>>
> Yes, it's valid to insert multiple snippets at the same instrumentation
> point; the "before/after" parameter to insertSnippet governs the relative
> order of execution, if that's relevant to you.
>
>> Thanks,
>> Wayne Motycka
>> E2 Lab @ Univ. of Nebraska - Lincoln
>>
>>
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>>
>
>
> --
> --bw
>
>
> Bill Williams
> Paradyn Project
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>