Adding a block to a function

A function consists of basic blocks. A basic block has an entry point. A basic block consists of a number of IR instructions, the last instruction being a terminator instruction. It has single exit point. LLVM provides the BasicBlock class to create and handle basic blocks. A basic block might have an entry point as its label, which indicates where to insert the next instructions. We can use the IRBuilder object to hold these new basic block IR.