[LLVMdev] problem with using DSA for a side-effect analysis

Vikram S. Adve vadve at cs.uiuc.edu
Thu Apr 3 21:31:40 PDT 2008

What I was hoping is that the internal implementation of the ModRef  
API in DSAA has that kind of information.  It needs to do exactly what  
you described with computeNodeMapping to implement the AliasAnalysis  

Andrew, my question was whether the ModRef info is computed by the - 
dsaa implementation.  If so, that code might be reusable (either  
directly, by exposing it through a separate interface) or indirectly  
(by duplicating) for what Zvonimir wants.


On Apr 3, 2008, at 4:53 PM, Zvonimir Rakamaric wrote:

> Thanks guys!
> I was looking into ModRef before, but I don't think that's exactly
> what I need. ModRef API call getModRefInfo requires a Value to be
> passed to it. However, some memory location M (which is a <DSNode,
> offset> pair) visible to the caller can be modified in the callee
> without any Value in the caller actually pointing to that location. I
> also need to capture those...
> I would need a call similar to getModRefInfo, just where second
> parameter is not a Value, but a DSNodeHandle pointing to the memory
> location in the caller whose ModRef status I would like to find out.
> Do you maybe have anything similar to that?
> -- Zvonimir
>> The ModRef info is directly available through the alias analysis dsa
>> client, and certainly easier to use.
>> Andrew
>> On Thu, Apr 3, 2008 at 1:28 PM, Vikram S. Adve <vadve at cs.uiuc.edu>  
>> wrote:
>>> Andrew, there used to be some code to compute the ModRef behavior of
>>> functions using DS graphs.  Does that code  still exist in svn?   
>>> What
>>> Zvonimir is asking is essentially that, although perhaps he needs it
>>> as DS nodes explicitly rather than via the generic queries in the
>>> AliasAnalysis interface.
>>> --Vikram
>>> http://www.cs.uiuc.edu/~vadve
>>> http://llvm.org/
>>> On Apr 3, 2008, at 12:45 PM, Andrew Lenharth wrote:
>>>> On Thu, Apr 3, 2008 at 12:29 PM, Zvonimir Rakamaric <zrakamar at gmail.com
>>>>> wrote:
>>>>> Currently I am using DSGraph::computeNodeMapping to do the task,
>>>>> but I
>>>>> am not sure if that's the way to go....
>>>> I believe that is the correct function to use.
>>>> Andrew
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