llvm dev - Feb 2013 - [LLVMdev] How to get type of a call instruction

I need to get the type of a call instruction to typecast a (void*) pointer
to the type of the function which is called. How can I achieve that?
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Blind Faith <person.of.book at gmail.com> writes:
> I need to get the type of a call instruction to typecast a (void*) pointer
> to the type of the function which is called. How can I achieve that?
CallInst::getType    ?

CallInst is derived from Value, Value's have a type, which you obtain
with getType method.

Then you use BitCastInst for the typecast.

But maybe you are not talking about the type of the value returned by
the call, but the type of the called function (you want to typecast a
void* to a function pointer.) Then you use CallInst::getCalledFunction
and Function::getFunctionType. Finally, you need BitCastInst for the
typecast.

The Doxygen documentation is handy for that. Using clang & opt for
looking at the llvm assembly and/or LLVM C++ API representation helps a
lot too.

[please keep the discussion on-list, thanks]

Blind Faith <person.of.book at gmail.com> writes:
> CallInst::getCalledFunction followed by Function::getFunctionType does not
> work for indirect calls, because getCalledFunction returns NULL for
> indirect calls, and my focus is indirect calls. Any idea how to get the
> Function Type from indirect calls?
Maybe CallInst::getCalledValue ?

getCalledValue - Get a pointer to the function that is invoked by this
instruction

Note that it returns a Value*, not a Function*.

Then you can use Value::getType.