llvm dev - Apr 2008 - [LLVMdev] problem with using DSA for a side-effect analysis

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

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  
interface.

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.

--Vikram
http://www.cs.uiuc.edu/~vadve
http://llvm.org/



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
> _______________________________________________
> 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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On Thu, Apr 3, 2008 at 4:53 PM, Zvonimir Rakamaric <zrakamar at gmail.com>
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?
I haven't looked at the dsaaa implementation for quite a while, but
that would be the place to start.  If the DSNodeHandle corrosponds to
anything in the current function, you could just use that as a value,
but it won't always.  Eitherway, seeing how DSAaa does this would be
the best code to start from.

Andrew

On Fri, Apr 4, 2008 at 2:38 AM, Andrew Lenharth <andrewl at lenharth.org>
wrote:
> On Thu, Apr 3, 2008 at 4:53 PM, Zvonimir Rakamaric <zrakamar at
gmail.com> 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?
>
>  I haven't looked at the dsaaa implementation for quite a while, but
>  that would be the place to start.  If the DSNodeHandle corrosponds to
>  anything in the current function, you could just use that as a value,
>  but it won't always.  Eitherway, seeing how DSAaa does this would be
>  the best code to start from.
Thanks!
I already had most of the code for it already written, staring at the
DSAaa helped me to fix a couple of problems. It seems to be working
perfectly now...
Btw, apart from the difference I already mentioned, DSAaa modref is
also not so good fit for me because it is not field-sensitive...

-- Zvonimir