LLVM (Low Level Virtual Machine)

• LLVM is a set of compiler and toolchain technologies
• Allows creating frontends for any programming language
• Allows creating backends for any instruction set architecture
• It is designed around a language independent Intermediate Representation (IR)

Steps

• Frontend

• Source Code

• Lexical Analysis (AST)

• IR Code

• Middle

• IR code optimization

• Backend

• IR code

• Machine code

Bulding LLVM

Lexer

• Scans the source code and breaks into a collection of tokens
• Tokens
• Identifier: x, color, UP
• Keyword: if, while, return
• Separator: }, (, ;
• Operator: +, <, =
• Literal: true, 6.02e23, "music"

AST (Abstract Syntax Tree)

• Tree to represent to structure of the code and the relation between the tokens

Parser

• Builds the AST

IR

• Generates the intermediate representation code