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

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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

Getting started with TableGen

The name TableGen stems from its original usage – generating tables. For instance, TableGen generates the table that represents all the registers of a target. TableGen outgrew this purpose and is now used to model a wide range of things, from Clang’s command-line options to multi-level intermediate representation (MLIR) operations’ boilerplate C++ code, or used directly within LLVM to generate the instruction selection tables, and so on.

Fundamentally, TableGen is a DSL to produce records. A record is an entity with a name and an arbitrary number of fields, where each field has its own type.

How these records are used and what output TableGen generates from them depends on the specific TableGen backend.

We will survey one of the TableGen backends used in this book in the Discovering a TableGen backend section, but you will learn how to use this backend and the other ones in the relevant upcoming chapters.

TableGen...