LLVM IR to Machine code(Arm)

The scheduling phase takes the DAG of target instructions from the selection phase and assigns an order. The scheduler can pick an order depending on various constraints of the machines (i.e. order for minimal register pressure or try to cover instruction latencies). Once an order is established, the DAG is converted to a list of MachineInstrs and the SelectionDAG is destroyed.

How the DAG is converted into list of MachineInstrs . Where I can see the code of this conversion in llvm source code ?