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

Chapter 4: TableGen Development

TableGen is a domain-specific language (DSL) that was originally developed in Low-Level Virtual Machine (LLVM) to express processors' instruction set architecture (ISA) and other hardware-specific details, similar to the GNU Compiler Collection's (GCC's) Machine Description (MD). Thus, many people learn TableGen when they're dealing with LLVM's backend development. However, TableGen is not just for describing hardware specifications: it is a general DSL useful for any tasks that involve non-trivial static and structural data. LLVM has also been using TableGen on parts outside the backend. For example, Clang has been using TableGen for its command-line options management. People in the community are also exploring the possibility to implement InstCombine rules (LLVM's peephole optimizations) in TableGen syntax.

Despite TableGen's universality, the language's core syntax has never been widely understood by many...