kotlin-fork/kotlin-native/tools/llvm_builder/README.md

LLVM Build Infrastructure

package.py script automates downloading, building and packing of LLVM distribution used by Kotlin/Native.

Requirements

• Check LLVM requirements. Note that:
  • Visual Studio 2017 is required on Windows
  • Xcode is required on macOS
• Python 3
• ninja
• git
• CMake

Usage

Just run

python3 package.py

It will create a llvm-distribution folder which contains LLVM distribution.
Note that build will take a lot of time and all your machine cores. 😈
See HACKING.md on how to use freshly built distribution.

Building distribution for end-users

By default, package.py installs a lot of LLVM components that is not really required to use Kotlin/Native compiler. To build only essential parts, run the following command:

python3 package.py --build-targets install-distribution --distribution-components $DISTRIBUTION_COMPONENTS

Set of required $DISTRIBUTION_COMPONENTS depends on OS:

OS	Distribution components
Windows	clang libclang lld llvm-cov llvm-profdata llvm-ar clang-resource-headers
macOS	clang libclang lld llvm-cov llvm-profdata llvm-ar clang-resource-headers
Linux	clang libclang lld llvm-cov llvm-profdata llvm-ar clang-resource-headers compiler_rt

Tuning

Run python3 package.py -h to check how one can tune script's behavior. Some examples:

• --pack creates an archive (zip on Windows, tar.gz on macOS and Linux) with distribution alongside with its SHA256.
• --install-path allows overriding distribution's output directory.
• --num-stages specifies number of steps in build. Passing 2 or more makes bootstrap build which means that LLVM will build itself by using distribution from the previous step.
• --stage0 allows using existing LLVM toolchain for bootstrapping.
• --build-targets specifies what targets will be passed to Ninja.
• --distribution-components is a list of components that will be installed with install-distribution build target.

Docker

You can use Docker to build LLVM for Linux:

docker build -t kotlin-llvm-builder .
docker run --rm -it -v <HOST_PATH>:/output kotlin-llvm-builder --install-path /output/llvm-11.1.0-linux-x64 --pack

Known problems

1. libcxx and compiler-rt are built as projects, not runtimes.
2. No way to run LLVM tests out of the box.