Minikotlin Compiler Converts Kotlin to WebAssembly with No External Dependencies

Overview of Minikotlin

Minikotlin is a new Kotlin compiler designed from scratch in C, specifically for outputting WebAssembly. Unlike traditional Kotlin compilers that rely on the JVM or LLVM, Minikotlin directly transforms Kotlin source code into WebAssembly GC bytecode, aiming for a streamlined compilation process without external dependencies.

Compilation Process

The compiler takes .kt files and processes them as a single unit to maintain visibility and interaction between different classes. This unique approach means that classes are compiled directly into WebAssembly supported structures, allowing for optimized memory allocation without traditional heap overhead.

Memory Management and Features

All Kotlin classes become garbage-collected struct types in Minikotlin, with properties functioning as actual struct fields. This facilitates a more efficient allocation process through struct.new, a method that avoids manual memory management. Additionally, advanced language features such as enums, sealed hierarchies, and smart-casting are supported and properly lowered to the WebAssembly GC type system.

Unique Characteristics

Minikotlin distinguishes itself with custom IRs for intermediate representation prior to the final WebAssembly output. This detailed lowering process ensures that all Kotlin features integrate seamlessly into the WebAssembly target, enhancing both functionality and performance. The compiler operates completely within the WebAssembly environment, omitting the need for an installed toolchain.