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

Chapter 7: Handling AST

In the previous chapter, we learned how Clang's preprocessor handles preprocessing directives in C-family languages. We also learned how to write different kinds of preprocessor plugins, such as pragma handlers, to extend Clang's functionalities. Those skills are especially useful when it comes to implementing field-specific logic or even custom language features.

In this chapter, we're going to talk about a semantic-aware representation of the original source code file once it has been parsed, known as an Abstract Syntax Tree (AST). An AST is a format that carries rich semantic information, including types, expression trees, and symbols, to name a few. It is not only used as a blueprint to generate LLVM IR for later ...