You're reading from LLVM Code Generation A deep dive into compiler backend development

Product type Paperback

Published in May 2025

Publisher Packt

ISBN-13 9781837637782

Length 620 pages

Edition 1st Edition

Languages

C++

Tools

LLVM

Concepts

Programming Language

Author (1):

Quentin Colombet

View More author details

Table of Contents (30) Chapters

Preface

1. Part 1: Getting Started with LLVM

2. Building LLVM and Understanding the Directory Structure FREE CHAPTER

3. Contributing to LLVM

4. Compiler Basics and How They Map to LLVM APIs

5. Writing Your First Optimization

6. Dealing with Pass Managers

7. TableGen – LLVM Swiss Army Knife for Modeling

8. Part 2: Middle-End: LLVM IR to LLVM IR

9. Understanding LLVM IR

10. Survey of the Existing Passes

11. Introducing Target-Specific Constructs

12. Hands-On Debugging LLVM IR Passes

13. Part 3: Introduction to the Backend

14. Getting Started with the Backend

15. Getting Started with the Machine Code Layer

16. The Machine Pass Pipeline

17. Part 4: LLVM IR to Machine IR

18. Getting Started with Instruction Selection

19. Instruction Selection: The IR Building Phase

20. Instruction Selection: The Legalization Phase

21. Instruction Selection: The Selection Phase and Beyond

22. Part 5: Final Lowering and Optimizations

23. Instruction Scheduling

24. Register Allocation

25. Lowering of the Stack Layout

26. Getting Started with the Assembler

27. Unlock Your Book’s Exclusive Benefits

28. Other Books You May Enjoy

29. Index

Debugging the TableGen framework

When you interact with TableGen, it may not be immediately obvious what part of TableGen fails you, or how you misused it!

In this section, you will learn ways to determine what goes wrong. The way to fix the problem may, however, be backend-specific, and given the sheer volume of TableGen backends, we will not cover this in this book. However, we give you general guidance on how to approach them.

Let’s start with the basics!

Identifying the failing component

As you learned in Getting started with TableGen, a TableGen workflow implies several components – the frontend, the backend, and the use of the generated output in LLVM.

To identify which component is at fault, you need to identify when the failure occurs:

If the failure occurs while producing the .inc file, the problem is either with the TableGen frontend or backend, the syntax you used, or how you used the specific constructs (class or record) of...