Book Image

LLVM Techniques, Tips, and Best Practices Clang and Middle-End Libraries

By : Min-Yih Hsu
Book Image

LLVM Techniques, Tips, and Best Practices Clang and Middle-End Libraries

By: Min-Yih Hsu

Overview of this book

Every programmer or engineer, at some point in their career, works with compilers to optimize their applications. Compilers convert a high-level programming language into low-level machine-executable code. LLVM provides the infrastructure, reusable libraries, and tools needed for developers to build their own compilers. With LLVM’s extensive set of tooling, you can effectively generate code for different backends as well as optimize them. In this book, you’ll explore the LLVM compiler infrastructure and understand how to use it to solve different problems. You’ll start by looking at the structure and design philosophy of important components of LLVM and gradually move on to using Clang libraries to build tools that help you analyze high-level source code. As you advance, the book will show you how to process LLVM IR – a powerful way to transform and optimize the source program for various purposes. Equipped with this knowledge, you’ll be able to leverage LLVM and Clang to create a wide range of useful programming language tools, including compilers, interpreters, IDEs, and source code analyzers. By the end of this LLVM book, you’ll have developed the skills to create powerful tools using the LLVM framework to overcome different real-world challenges.
Table of Contents (18 chapters)
1
Section 1: Build System and LLVM-Specific Tooling
6
Section 2: Frontend Development
11
Section 3: "Middle-End" Development

Technical requirements

In Chapter 1, Saving Resources When Building LLVM, we showed you how to build LLVM. Those instructions, however, did not build Clang. To include Clang in the build list, please edit the value that's been assigned to the LLVM_ENABLE_PROJECTS CMake variable, like so:

$ cmake -G Ninja -DLLVM_ENABLE_PROJECTS="clang;clang-tools-extra"

The value of that variable should be a semi-colon-separated list, where each item is one of LLVM's subprojects. In this case, we're including Clang and clang-tools-extra, which contains a bunch of useful tools based on Clang's techniques. For example, the clang-format tool is used by countless open source projects, especially large-scale ones, to impose a unified coding style in their code base.

Adding Clang to an existing build

If you already have an LLVM build where Clang was not enabled, you can edit the LLVM_ENABLE_PROJECTS CMake argument's value in CMakeCache.txt without invoking...