llvm dev - Nov 2012 - [LLVMdev] Inconsistent result with CallGraph

Hello:

We are working with LLVM-3.1 and we have a problem.This is the code we have
executed:

virtual void getAnalysisUsage( llvm::AnalysisUsage & info ) const {

   info.addRequired<CallGraph>();

   ...

}

...

virtual bool runOnModule( Module & M )

{

...

CallGraph &CG = this->getAnalysis<CallGraph>();

CallGraphNode *cgn;

unsigned nref;

for(CallGraph::const_iterator I=CG.begin(),E=CG.end();I!=E;I++)

{

    cgn=I->second;

    if((cgn)&&(cgn->getFunction()))

    {

          nref=cgn->getNumReferences();

         
llvm::dbgs()<<"uses:"<<nref<<"\n";

          cgn->dump();

    }

}

...

}

In a simple program with only one function (Main), this is the output:

uses:0

Call graph node for function: 'main'<<0x7f928340c760>> 
#uses=1


We have been searching in llvm files and dump function calls
getNumReferences() (which is in Callgraph.h). And it is assumed that the
call cgn->getNumReferences() references to the same function. Why are we
getting different values? Dump shows uses=1, and cgn->getNumReferences()
shows uses=0;

We are writing a Module pass as you can see in the previous code. We have
this pass registered as:

char PARALLWARE::ID = 0;

static RegisterPass<PARALLWARE> X( "parallware","run
Parallware source to
source autoparallel compiler");


Is this a bug or we are making a mistake?

Thank you for your time. Best regards
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Hi Eugenio, I took a quick look at the 3.2 code and as far as I can see it is
impossible to get what you get.  So I suggest you try running under valgrind
to see if you are using freed memory or something like that.

Ciao, Duncan.

On 28/11/12 13:00, Eugenio Novás Cortés wrote:
> Hello:
>
> We are working with LLVM-3.1 and we have a problem.This is the code we have
> executed:
>
> virtual void getAnalysisUsage( llvm::AnalysisUsage & info ) const {
>
>     info.addRequired<CallGraph>();
>
>     ...
>
> }
>
> ...
>
> virtual bool runOnModule( Module & M )
>
> {
>
> ...
>
> CallGraph &CG = this->getAnalysis<CallGraph>();
>
> CallGraphNode *cgn;
>
> unsigned nref;
>
> for(CallGraph::const_iterator I=CG.begin(),E=CG.end();I!=E;I++)
>
> {
>
>      cgn=I->second;
>
>      if((cgn)&&(cgn->getFunction()))
>
>      {
>
>            nref=cgn->getNumReferences();
>
>           
llvm::dbgs()<<"uses:"<<nref<<"\n";
>
>            cgn->dump();
>
>      }
>
> }
>
> ...
>
> }
>
> In a simple program with only one function (Main), this is the output:
>
> uses:0
>
> Call graph node for function: 'main'<<0x7f928340c760>> 
#uses=1
>
>
> We have been searching in llvm files and dump function calls
getNumReferences()
> (which is in Callgraph.h). And it is assumed that the
> call cgn->getNumReferences() references to the same function. Why are we
getting
> different values? Dump shows uses=1, and cgn->getNumReferences() shows
uses=0;
>
> We are writing a Module pass as you can see in the previous code. We have
this
> pass registered as:
>
> char PARALLWARE::ID = 0;
>
> static RegisterPass<PARALLWARE> X( "parallware","run
Parallware source to
> source autoparallel compiler");
>
>
> Is this a bug or we are making a mistake?
>
> Thank you for your time. Best regards
>
>
>
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>