Book Image

Learn LLVM 12

By : Kai Nacke
Book Image

Learn LLVM 12

By: Kai Nacke

Overview of this book

LLVM was built to bridge the gap between compiler textbooks and actual compiler development. It provides a modular codebase and advanced tools which help developers to build compilers easily. This book provides a practical introduction to LLVM, gradually helping you navigate through complex scenarios with ease when it comes to building and working with compilers. You’ll start by configuring, building, and installing LLVM libraries, tools, and external projects. Next, the book will introduce you to LLVM design and how it works in practice during each LLVM compiler stage: frontend, optimizer, and backend. Using a subset of a real programming language as an example, you will then learn how to develop a frontend and generate LLVM IR, hand it over to the optimization pipeline, and generate machine code from it. Later chapters will show you how to extend LLVM with a new pass and how instruction selection in LLVM works. You’ll also focus on Just-in-Time compilation issues and the current state of JIT-compilation support that LLVM provides, before finally going on to understand how to develop a new backend for LLVM. By the end of this LLVM book, you will have gained real-world experience in working with the LLVM compiler development framework with the help of hands-on examples and source code snippets.
Table of Contents (17 chapters)
Section 1 – The Basics of Compiler Construction with LLVM
Section 2 – From Source to Machine Code Generation
Section 3 –Taking LLVM to the Next Level

Contents of the LLVM mono repository

In Chapter 1, Installing LLVM, you cloned the LLVM mono repository. This repository contains all LLVM top-level projects. They can be grouped as follows:

  • LLVM core libraries and additions
  • Compilers and tools
  • Runtime libraries

In the next sections, we will take a closer look at these groups.

LLVM core libraries and additions

The LLVM core libraries are in the llvm directory. This project provides a set of libraries with optimizers and code generation for well-known CPUs. It also provides tools based on these libraries. The LLVM static compiler llc takes a file written in LLVM intermediate representation (IR) as input and compiles it into either bitcode, assembler output, or a binary object file. Tools such as llvm-objdump and llvm-dwarfdump let you inspect object files, and those such as llvm-ar let you create an archive file from a set of object files. It also includes tools that help with the development of LLVM itself...