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

Working with the new AnalysisManager

Modern compiler optimizations can be complex. They usually require lots of information from the target program in order to make correct decisions and optimal transformations. For example, in the Writing an LLVM Pass for the new PassManager section, LLVM used the noalias attribute to calculate memory aliasing information, which might eventually be used to remove redundant memory loads.

Some of this information – called analysis, in LLVM – is expensive to evaluate. In addition, a single analysis might also depend on other analyses. Therefore, LLVM creates an AnalysisManager component to handle all tasks related to program analysis in LLVM. In this section, we are going to show you how to use AnalysisManager in your own Passes for the sake of writing more powerful and sophisticated program transformations or analyses. We will also use a sample project, HaltAnalyzer, to drive our tutorial here. The next section will provide you with...