[llvm] r193412 - Call destroy from ~BasicCallGraph.

[Nick Lewycky]

Rafael Espindola wrote:
> Author: rafael
> Date: Fri Oct 25 10:01:34 2013
> New Revision: 193412
>
> URL: http://llvm.org/viewvc/llvm-project?rev=193412&view=rev
> Log:
> Call destroy from ~BasicCallGraph.
>
> This fix a memory leak found by valgrind.
>
> Calling it from the base class destructor would not destroy the BasicCallGraph
> bits.
>
> FIXME: BasicCallGraph is the only thing that inherits from CallGraph. Can
> we merge the two?

That's an interesting question. What would a derived CallGraph be 
allowed to do which BasicCallGraph doesn't?

Can we have call sites in functions that are declared but not defined? I 
don't think so because the call edge itself is represented with a 
CallInst/InvokeInst. The API is written in terms of llvm::CallSite.

Could we have a CallGraph which does complex analysis to resolve 
indirect call sites? I don't think so, users of the CallGraph API assume 
that edges are guaranteed to be direct and will crash if they aren't.

We could replace getRoot() but does that help? Can I have a Module which 
would be miscompiled if I used a BasicCG? And what to 
getExternalCallingNode / getCallsExternalNode do? They return a 
CallGraphNode but again the API is still written in terms of CallSites, 
and those CallSites can't refer to things that aren't in the Module anyways?

Is anybody using this?

Nick