What this book covers

Chapter 1, Environment Setup, describes the basic steps required to set up the environment for future experiments with Clang, suitable for Unix-based systems such as Linux and Darwin (macOS). In addition, readers will learn how to download, configure, and build LLVM source code. We will also create a simple Clang Tool to verify the syntax of the provided source code.

Chapter 2, Clang Architecture, examines the internal architecture of the Clang compiler. Starting with the basic concept of a compiler, we will explore how it is implemented in Clang. We will look at various parts of the compiler, including the driver, preprocessor (lexer), and parser. We will also examine examples that show how the C++ standard is implemented in Clang.

Chapter 3, Clang AST, talks about Clang Abstract Syntax Tree (AST), which is the basic data structure produced by the parser. We will explore how the AST is organized in Clang and how it can be traversed. We will also delve into AST Matchers — a powerful tool provided by Clang for locating specific AST nodes.

Chapter 4, Basic Libraries and Tools, explores basic LLVM libraries and tools, including the LLVM Abstract Data Type (ADT) library, used across all LLVM code. We will investigate TableGen, a Domain-Specific Language (DSL) used to generate C++ code in various parts of LLVM. Additionally, we will explore LLVM Integrated Tester (LIT) tool used for creating powerful end-to-end tests. Using the knowledge gained, we will create a simple Clang plugin to estimate source code complexity.

Chapter 5, Clang-Tidy Linter Framework, covers Clang-Tidy, a linter framework based on Clang AST, and creates a simple Clang-Tidy check. We will also discuss how compilation errors affect the AST and the results provided by different Clang Tools, such as Clang-Tidy.

Chapter 6, Advanced Code Analysis, goes further and considers another advanced data structure used for code analysis: Control Flow Graphs (CFG). We will investigate typical cases for its application and create a simple Clang-Tidy check that utilizes this data structure.

Chapter 7, Refactoring Tools, Clang provides advanced tools for code modification and refactoring. We will explore different ways to create a custom refactoring tool, including one based on the Clang-Tidy linter framework. We will also explore Clang-Format, an extremely fast utility for automatic code formatting.

Chapter 8, IDE Support and Clangd, presents Clangd - a Language Server used in various IDEs, such as Visual Studio Code (VS Code), to provide intelligent support, including navigation and code modification. Clangd exemplifies the utility of the powerful modular architecture of LLVM. It utilizes various Clang tools, such as Clang-Tidy and Clang-Format, to enhance the development experience in VS Code. Compiler performance is crucial for this tool, and we will explore several techniques Clangd employs to improve its performance, thereby offering the best experience to developers.

Appendix 1: Compilation Database, describes the Compilation Database—a method for providing complex compilation commands to different Clang Tools. This functionality is crucial for integrating Clang Tools such as Clangd and Clang-Tidy into real C/C++ projects.

Appendix 2: Build Speed Optimizations, covers several compiler performance optimizations that can be used to enhance compiler performance. We will cover Clang precompiled headers and Clang modules, which represent a serialized AST that can be loaded much faster than building it from scratch.