Book Image

LLVM Essentials

By : Mayur Pandey, Suyog Sarda, David Farago
Book Image

LLVM Essentials

By: Mayur Pandey, Suyog Sarda, David Farago

Overview of this book

LLVM is currently the point of interest for many firms, and has a very active open source community. It provides us with a compiler infrastructure that can be used to write a compiler for a language. It provides us with a set of reusable libraries that can be used to optimize code, and a target-independent code generator to generate code for different backends. It also provides us with a lot of other utility tools that can be easily integrated into compiler projects. This book details how you can use the LLVM compiler infrastructure libraries effectively, and will enable you to design your own custom compiler with LLVM in a snap. We start with the basics, where you’ll get to know all about LLVM. We then cover how you can use LLVM library calls to emit intermediate representation (IR) of simple and complex high-level language paradigms. Moving on, we show you how to implement optimizations at different levels, write an optimization pass, generate code that is independent of a target, and then map the code generated to a backend. The book also walks you through CLANG, IR to IR transformations, advanced IR block transformations, and target machines. By the end of this book, you’ll be able to easily utilize the LLVM libraries in your own projects.
Table of Contents (14 chapters)
LLVM Essentials
About the Authors
About the Reviewer


Memory operations form an important instruction for most of the target architecture. Some of the architectures have sophisticated instructions to move data in and out of the memory. Some even perform binary operations directly on the memory operands, while some of them load data from memory into registers and then perform operations on them (CISC vs RISC). Many load-store operations are also done by LLVM instrinsics. For examples, please refer to

LLVM IR provides a common playfield for all the architectures. It provides elementary instructions for data operations on memory or on aggregate data types. The architectures, while lowering LLVM IR, may combine IR instructions to emit their specific instructions. In this chapter, we went through some advanced IR instructions and also looked into examples of them. For a detailed study, refer to, which provides the authoritative resource...