[LLVMdev] A few beginner level questions..

[Chris Lattner]

On Wed, 17 Nov 2004, Reid Spencer wrote:
> > 2. For an application , for every instruction if its a call
> > instruction I try to print out the called function as below ..
> >
> > void pass01a::instruct_show(Instruction* I){
> >    if ( isa<CallInst>(*I) ){
> >        const CallInst     *CI      = cast<CallInst>(I);
> >        const Function    *Func  = CI->getCalledFunction() ;
> >        std::cerr<<":calledFunction:"<<Func->getName();
> >    }
> > }

As a general comment, the above could be rewritten like this:

 void pass01a::instruct_show(Instruction* I){
    if (const CallInst *CI = dyn_cast<CallInst>(*I) ){
        const Function    *Func  = CI->getCalledFunction() ;
        std::cerr<<":calledFunction:"<<Func->getName();
    }

... saving you a line of code ...

> > Now it works fine for some application but for one of the benchmark in
> > MIBENCH , i am getting the following error .. Is there something wrong
> > with my coding or llvm itself .? Is there any simpler way to extract
> > the function names?

There is a problem with your code, though I don't blame you.  I've updated
the comment on the getCalledFunction() method to read this:

  /// getCalledFunction - Return the function being called by this instruction
  /// if it is a direct call.  If it is a call through a function pointer,
  /// return null.

I hope that helps,

-Chris

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