LLVM Cookbook

Chapter 6. Target-independent Code Generator

In this chapter, we will cover the following recipes:

• The life of an LLVM IR instruction
• Visualizing the LLVM IR CFG using GraphViz
• Describing the target using TableGen
• Defining an instruction set
• Adding a machine code descriptor
• Implementing the MachineInstrBuilder class
• Implementing the MachineBasicBlock class
• Implementing the MachineFunction class
• Writing an instruction selector
• Legalizing SelectionDAG
• Optimizing SelectionDAG
• Selecting instructions from the DAG
• Scheduling instructions in SelectionDAG

Introduction

After optimizing the LLVM IR, it needs to be converted into machine instructions for execution. The machine-independent code generator interface gives an abstract layer that helps convert IR into machine ...