From Source to Bytecode: Understanding the Kotlin Compilation Process

Dive into the inner workings of the Kotlin compiler in this informative session. We'll explore how Kotlin code is transformed into JVM bytecode, covering key stages such as lexical analysis, parsing, semantic analysis, intermediate representation (IR) and code generation. Ideal for Kotlin developers and software engineers, this talk will enhance your understanding of the compilation process and help you write more efficient code. Join us to decode the journey from source to bytecode in Kotlin!

Transcript

1. From Source to Bytecode: Understanding the Kotlin Compilation Process Presented by Theophilus Kibet Android Engineer
2. What is a compiler? Kotlin Compiler Overview Resources What's Up today? Questions
3. A program which translates a program in a source language to a program in target language. . What is a compiler? P. 04 Bemefits OF Coroutines Source Code Compiler Target/machine code
4. 01 P. 04 Bemefits OF Coroutines .kt files Kotlin Compiler Kotlin Compiler JVM Bytecode JavaScript LLVM Bitcode Wasm
5. 02 P. 04 Bemefits OF Coroutines .kt Kotlin Compiler frontend backend target code
6. 03 P. 04 Bemefits OF Coroutines .kt Kotlin Compiler backend target code lexer parser semantic analyzer tokens syntax tree syntax tree + semantic info
7. 04 P. 04 Bemefits OF Coroutines .kt Kotlin Compiler frontend target code intermediate code generator & optimizer machine code generator & optimizer syntax tree + semantic info intermidiate representation
8. Consumes plain text of a program and groups together individual characters to form complete tokens. Token - has a value and a token type. Lexer P. 04 fun getSpeaker(id: String) { }
9. fun KtModifierKeywordToken.FUN getSpeaker KtToken.IDENTIFIER ( KtSingleValueToken.LPAR id KtToken.IDENTIFIER : KtSingleValueToken.COLON and so on..... Tokens
10. Consumes tokens and groups them together into complete statements and expressions, guided by the grammar. It outputs a syntax tree. Parser P. 04
11. A set of rules defining the language structure. ‘fun’ identifier ‘(’ parameters ‘)’ ‘{’ statements ‘}’ NB:this is just a sample rule, Kotlin has many rules for functions. Grammar
12. -> grammatical structure of the program. Abstract syntax tree(AST) contains only information which are needed for processing the source input. Concrete syntax tree(CST) contains all the information derived from the source input, this includes things like whitespaces and comments. NB:Kotlin Compiler produces a CST, referred as Program Structure Interface(PSI). Syntax tree
13. Element.FUN Token.fun Element.IDENTIFIER Element.VALUE_PARAMETER_ LIST Token.LBRACE Token.RBRACE Token.LPAR Token.RPAR Element.VALUE_PARAMETER Element.IDENTIFIER Token.COLON Element.TYPE_REFERENCE fun getSpeaker(id: String) { }
14. fun getSpeaker(id: String) { } Use PSIViewer plugin to view
15. P. 04 Bemefits OF Coroutines .kt PSI2FIR backend target code lexer parser semantic analyzer tokens PSI syntax tree + semantic info Transforms PSI to FIR.
16. -> Enhanced PSI designed for code resolution. -> Some optimization is done on the FIR. e.g replacing if statements with when and for loops with while Frontend Intermediate Representation Use FIR Tree plugin to view
17. Resolves Semantic info. imports. types Checks errors and report. Semantic Analyzer
18. P. 04 Bemefits OF Coroutines .kt frontend target code intermediate code generator & optimizer machine code generator & optimizer FIR intermidiate representation FIR2IR Transforms FIR to IR.
19. -> Enhanced FIR designed for code generation. -> More optimization is done on the IR, these are mostly architecture independent. Intermediate Representation
20. Constant folding. converting an expression by combining multiple constants into a single constant. Strength Reduction. converting a special case of an expensive operation into a less expensive. e.g 3^3 becomes 3*3 Optimizations on the IR
21. Compiler Explorer
22. -> Hard to navigate and run the project. -> No resources resources on getting dumps for every stage, you have to write a compiler plugin. NB: You can get help on Kotlin Slack - #compiler Challenges
23. 18 Resources Kotlin-Compiler-Crash-Course by Amanda What Everyone Must Know About The NEW Kotlin K2 Compiler Exploring Kotlin Performance with Romain Guy Kotlin-script-parser-test Kotlin Repository Compiler Explorer Kotlin Explorer
25. Thank @_kibetheophilus Theophilus Kibet You Contact kibettheophilus