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

A crash course on LLDB

Debuggers are a great tool for inspecting the state of a program at runtime.

LLDB is the LLVM debugger – that is, a debugger built using the LLVM project.

A debugger lets you run a program, stop it at any point, and inspect its state.

Depending on how your program was built, your debug session may be more or less close to the source code. A program built with a lower optimization level (for example, O0) is going to reflect the way the program was written more naturally than a program built with a higher optimization level.

To put it in simple terms, if you want to use a debugger to inspect your program at the source level, you’re better off building your program with optimization disabled (-O0) and the debug information enabled (-g). This is exactly what the Debug CMake build type is about.

Beyond that, you may have some information, such as the call stack, but you may not have easy access to symbolic information such as the...