[llvm-dev] Finding callees of a function

[Tim Northover via llvm-dev]

Hi Marc,

On Wed, 15 Jan 2020 at 09:52, Marc via llvm-dev <llvm-dev at lists.llvm.org> wrote:
>   bool Foo:runOnModule(Module &M) {
>     LLVMContext &C = M.getContext();
>     for (auto &F : M) {
>       // magic here
>
> if I want to know from which function (callee) each function is called -
> how can I do this?

To get the direct callers you would iterate through the users of F,
and check whether it's being used as the callee operand in a CallInst
or InvokeInst. Fortunately there's a CallSite class that abstracts
away many of the differences. So something like:

    for (auto &U : F.getUsers()) {
      if (auto CS = CallSite(U)) {
        if (CS->getCalledFunction() == F)
          doStuff(CS);
      }
    }

> I am aware that this will not work for calls that are made outside of
> the analyzed module.

Also indirect calls.

Cheers.

Tim.