[LLVMdev] The problem of densemap and loop

[Hanbing Li]

Dear John, 

First thing, the 3 loops in Densemap are all " Loop at depth 1 containing: %1<header><exiting>,%3,%5<latch> " in the 3 functions. 

The dense map is in a ImmutablePass. I got it in FunctionPass and tried insert the information in this FunctionPass. So to turn the FunctionPass to ModulePass may be a better idea? 

Another interesting thing: if just before the insertion, I used "L -> print(errs());" to print the Loop, there were 6 items in ls. BUT when I tried to read it in a ModulePass, I can't get the correct result. 
" 

for (Module::iterator FI = M.begin(), E = M.end(); FI != E; ) { 
F = FI++; 

if (!F->hasName() && !F->isDeclaration()){} 
else{ 

LoopInfo *LI = &getAnalysis<LoopInfo>(*F); 
WCETInfo *WI = &getAnalysis<WCETInfo>(); //WI is the ImmutablePass which contains the dense map 

for(LoopInfo::iterator i=LI->begin(); i!=LI->end(); ++i) { 
Loop *L = *i; 

int lb=0; 
lb=WI->outls(L); // the method: return ls.find(L)->second; 

} 

} 

} " 

Thank you 

Sincerely, 

Hanbing 

----- Mail original -----

> De: "John Criswell" <jtcriswel at gmail.com>
> À: "Hanbing Li" <hanbing.li at inria.fr>, llvmdev at cs.uiuc.edu
> Envoyé: Jeudi 28 Août 2014 18:59:52
> Objet: Re: [LLVMdev] The problem of densemap and loop

> Dear Hanbing,

> You haven't provided enough information to help diagnose the problem. It
> would help if you specified which 3 loops actually end up in the DenseMap.

> One thing to check for is if your code is in a FunctionPass. A FunctionPass
> computes its results anew each time it is run on a function, and so it's
> possible that this is the cause of the problem. Similarly, the Loop objects
> for each function might be deleted and re-allocated for new Loop objects
> every time you run the LoopAnalysis on a new function. That would make it
> look like you only have three elements when, in fact, you've added six
> elements but three were deallocated.

> Alternatively, you might have some something silly like making ls a local
> variable, so it gets destroyed each time you enter the function/method in
> which it appears.

> However, these are just guesses. I'm not certain it can be diagnosed even if
> you do provide more information.

> Regards,

> John Criswell

> On 8/28/14, 12:49 PM, Hanbing Li wrote:

> > Hello, everyone,
> 

> > I created a dense map like this: DenseMap<Loop *, int> ls;
> 
> > And I have a module which contains 3 functions:
> 
> > function F and it has a loop which is " Loop at depth 1 containing:
> > %1<header><exiting>,%3,%5<latch> "
> 
> > function G and it has two loops which are "
> 

> > Loop at depth 1 containing: %8<header><exiting>,%10,%14<latch>
> 

> > Loop at depth 1 containing: %1<header><exiting>,%3,%5<latch> "
> 
> > function main and it has 3 loops which are "
> 

> > Loop at depth 1 containing: %17<header><exiting>,%19,%23<latch>
> 

> > Loop at depth 1 containing: %8<header><exiting>,%10,%14<latch
> 

> > Loop at depth 1 containing: %1<header><exiting>,%3,%5<latch> "
> 
> > Then I tried to insert these loops into ls and the expected result is that
> > there are 6 items in ls after the insertion.
> 
> > But I got only 3.
> 

> > So my question is why this happened?
> 
> > The dense map uses the name of the loop to check if the element is in it?
> 
> > Is there anything wrong during my code?
> 

> > Looking forward to your answer.
> 

> > Thank you
> 

> > Sincerely,
> 

> > Hanbing
> 

> > _______________________________________________
> 
> > 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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