llvm dev - May 2015 - [LLVMdev] Processing functions in call graph SCC "order" with function-level analyses

Hi all,

I have one analysis pass that I want to perform on call graph SCCs. However, for
each function in the SCC, I need function-level analyses, like the dominator
tree and the memory dependency analysis.

I’ve been told before
<http://stackoverflow.com/questions/30059622/using-dominatortreewrapperpass-in-callgraphsccpass>
that these were not available from a CallGraphSCCPass. What would be the best
approach for me to access this information? Should I run the passes manually, or
is there another, more pass-scheduler-friendly approach?

Félix
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On 5/18/15 10:45 PM, Félix Cloutier wrote:
> Hi all,
>
> I have one analysis pass that I want to perform on call graph SCCs. 
> However, for each function in the SCC, I need function-level analyses, 
> like the dominator tree and the memory dependency analysis.
>
> I’ve been told before 
>
<http://stackoverflow.com/questions/30059622/using-dominatortreewrapperpass-in-callgraphsccpass>
that
> these were not available from a CallGraphSCCPass. What would be the 
> best approach for me to access this information? Should I run the 
> passes manually, or is there another, more pass-scheduler-friendly 
> approach?
I would write a ModulePass that simply iterates over the call graph.  
LLVM provides a CallGraph analysis which one can use to find SCCs; DSA 
has an analysis called CallTargets which does "real" CallGraph
analysis
(which means that it tries to reason about function pointers, though I 
cannot guarantee that its reasoning will be as accurate as you want).

If you use a ModulePass, can you analyze any part of the program you 
like, and you can use FunctionPasses.

Regards,

John Criswell
>
> Félix
>
>
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev

-- 
John Criswell
Assistant Professor
Department of Computer Science, University of Rochester
http://www.cs.rochester.edu/u/criswell

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Thanks John.

Does this solve the problem of analysis availability though? If I still have to
run the function analyses manually, I might as well keep rolling with the
CallGraphSCCPass. (I probably should have mentioned that this is what I’m using
right now.)

Félix
> Le 2015-05-19 à 10:12:32, John Criswell <jtcriswel at gmail.com> a
écrit :
> 
> On 5/18/15 10:45 PM, Félix Cloutier wrote:
>> Hi all,
>> 
>> I have one analysis pass that I want to perform on call graph SCCs.
However, for each function in the SCC, I need function-level analyses, like the
dominator tree and the memory dependency analysis.
>> 
>> I’ve been told before
<http://stackoverflow.com/questions/30059622/using-dominatortreewrapperpass-in-callgraphsccpass>
that these were not available from a CallGraphSCCPass. What would be the best
approach for me to access this information? Should I run the passes manually, or
is there another, more pass-scheduler-friendly approach?
> 
> I would write a ModulePass that simply iterates over the call graph.  LLVM
provides a CallGraph analysis which one can use to find SCCs; DSA has an
analysis called CallTargets which does "real" CallGraph analysis
(which means that it tries to reason about function pointers, though I cannot
guarantee that its reasoning will be as accurate as you want).
> 
> If you use a ModulePass, can you analyze any part of the program you like,
and you can use FunctionPasses.
> 
> Regards,
> 
> John Criswell
> 
>> 
>> Félix
>> 
>> 
>> _______________________________________________
>> LLVM Developers mailing list
>> LLVMdev at cs.uiuc.edu <mailto:LLVMdev at cs.uiuc.edu>        
http://llvm.cs.uiuc.edu <http://llvm.cs.uiuc.edu/>
>> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
<http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev>
> 
> 
> -- 
> John Criswell
> Assistant Professor
> Department of Computer Science, University of Rochester
> http://www.cs.rochester.edu/u/criswell
<http://www.cs.rochester.edu/u/criswell>
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