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

This chapter expects that you have a build of the clang executable. If you don't, please build it using the following command:

$ ninja clang

In addition, you can use the following command-line flag to print out the textual representation of AST:

$ clang -Xclang -ast-dump foo.c

For example, let's say foo.c contains the following content:

int foo(int c) { return c + 1; }

By using the -Xclang -ast-dump command-line flag, we can print out AST for foo.c:

TranslationUnitDecl 0x560f3929f5a8 <<invalid sloc>> <invalid sloc>
|…
`-FunctionDecl 0x560f392e1350 <foo.c:2:1, col:30> col:5 foo 'int (int)'
  |-ParmVarDecl 0x560f392e1280 <col:9, col:13> col:13 used c 'int'
  `-CompoundStmt 0x560f392e14c8 <col:16, col:30>
    `-ReturnStmt 0x560f392e14b8 <col:17, col:28>
      `-BinaryOperator 0x560f392e1498 &lt...