Find arguments of a function in LLVM IR

You can use Function::getArgumentList() method to get a list of function's arguments. Then, you traverse it with iterators - ArgumentListType::begin() and ArgumentListType::end().

See class Function documentation - http://llvm.org/doxygen/classllvm_1_1Function.html

UPD:

The current way of iterating over arguments is arg_begin()/arg_end()/args() methods.