Building LLVM for Kotlin/Native

This document describes how to compile LLVM distribution and use it to build Kotlin/Native.
Usually, you don't need to compile LLVM by yourself: it is downloaded automatically when you run or build Kotlin/Native compiler.

But if you don't want to download prebuilt LLVM or want to experiment with your own distribution, you come to the right place.

Part 1. Building the right LLVM version.

Use package.py script to build LLVM distribution the same way the Kotlin team does.

Part 2. Building Kotlin/Native against given LLVM distribution.

Change kotlin.native.llvm Gradle property to the absolute path of the freshly built LLVM distribution.

It's possible to:

• either edit gradle.properties,
• or pass -Pkotlin.native.llvm=<path> when executing Gradle tasks from the command line.

It's important to correctly specify llvm version. Look up <version> in <llvm-distribution>/lib/clang/<version>/include. kotlin.native.llvm.next.<host>.version Gradle property is used with llvm distributions provided by kotlin.native.llvm=<path>.

Now we are ready to build Kotlin/Native itself. The process is described in README.md.

NOTE: In gradle.properties we also have defined special default and next LLVM versions. The default version is the one Kotlin/Native uses, and the next is there to experiment during migration to another LLVM version.

Q&A

— Can I override .konan location?
— Yes, by setting $KONAN_DATA_DIR environment variable. See HACKING.md.

— Can I use another LLVM distribution without rebuilding Kotlin/Native?
— Yes, see HACKING.md.