llvm dev - Jan 2011 - [LLVMdev] Identify Loops from within FunctionPass, or possible to intermix different types of Passes?

LLVMers,

I have a traversal plan which needs to visit certain types of Functions. 
For each instruction in such functions, I will need to know:
1. is it located inside a loop
2. if yes, what level of loop nest it is currently in.

So on the highest level, it should be a FunctionPass. However, in order 
to identify loops and loop-nest levels, it should also be a LoopPass.

Is there a reasonably simple way to identify loop(s) within a function 
under FunctionPass?

(Any existing LLVM code that I can take a look?)

OR

Is it possible to intermix different types of LLVM Passes?

E.g.

class MyPass: public FunctionPass, public LoopPass{
   ...
public:
   bool runOnFunction(...);
   bool runOnLoop(...);
   ...
};

Does this make any sense?
I haven't seem to find any existing LLVM pass under such uses.


Thank you very much

Chuck

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On Jan 6, 2011, at 9:21 AM, Chuck Zhao wrote:
> LLVMers,
> 
> I have a traversal plan which needs to visit certain types of Functions.
For each instruction in such functions, I will need to know:
> 1. is it located inside a loop
> 2. if yes, what level of loop nest it is currently in.
> 
> So on the highest level, it should be a FunctionPass. However, in order to
identify loops and loop-nest levels, it should also be a LoopPass.
> 
> Is there a reasonably simple way to identify loop(s) within a function
under FunctionPass?
> 
> (Any existing LLVM code that I can take a look?)
Your FunctionPass can use LoopInfo to get this information.

-
Devang
> 
> OR
> 
> Is it possible to intermix different types of LLVM Passes?
> 
> E.g.
> 
> class MyPass: public FunctionPass, public LoopPass{
>   ...
> public:
>   bool runOnFunction(...);
>   bool runOnLoop(...);
>   ...
> };
> 
> Does this make any sense?
> I haven't seem to find any existing LLVM pass under such uses.
> 
> 
> Thank you very much
> 
> Chuck
> 
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
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I've never seen a LoopPass, but doing a function pass and grab the loop info
from "\llvm\Analysis\LoopInfo.h".
>From there just you use the LoopInfo api to grap the loop headers and loop
blocks and whatever else you want to do.

- Thank
Jeff Kunkel

On Thu, Jan 6, 2011 at 2:24 PM, Devang Patel <dpatel at apple.com> wrote:
>
> On Jan 6, 2011, at 9:21 AM, Chuck Zhao wrote:
>
>  LLVMers,
>
> I have a traversal plan which needs to visit certain types of Functions.
> For each instruction in such functions, I will need to know:
> 1. is it located inside a loop
> 2. if yes, what level of loop nest it is currently in.
>
> So on the highest level, it should be a FunctionPass. However, in order to
> identify loops and loop-nest levels, it should also be a LoopPass.
>
> Is there a reasonably simple way to identify loop(s) within a function
> under FunctionPass?
>
> (Any existing LLVM code that I can take a look?)
>
>
> Your FunctionPass can use LoopInfo to get this information.
>
> -
> Devang
>
>
> OR
>
> Is it possible to intermix different types of LLVM Passes?
>
> E.g.
>
> class MyPass: public FunctionPass, public LoopPass{
>   ...
> public:
>   bool runOnFunction(...);
>   bool runOnLoop(...);
>   ...
> };
>
> Does this make any sense?
> I haven't seem to find any existing LLVM pass under such uses.
>
>
> Thank you very much
>
> Chuck
>
>  _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>
>
>
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>
>
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