Installation

This work is in the process of upstreaming into nightly Rust. In the future a manual installation should not be neccessary anymore (unless you want to contribute to this project). Till then, you can follow the instructions below. Please be aware that the msvc target is not supported at the moment, all other tier 1 targets should work. Please open an issue if you have issues on a supported tier 1 target, or if you succesfully build this project on a tier2/tier3 target.

Build instructions

First you need to clone and configure this Rust fork:

git clone --depth=1 git@github.com:rust-lang/rust.git
cd rust
./configure --enable-llvm-link-shared --enable-llvm-plugins --enable-llvm-enzyme --release-channel=nightly --enable-llvm-assertions --enable-clang --enable-lld --enable-option-checking --enable-ninja --disable-docs

Afterwards you can build rustc using:

./x.py build --stage 1 library

Afterwards rustc toolchain link will allow you to use it through cargo:

rustup toolchain link enzyme build/host/stage1
rustup toolchain install nightly # enables -Z unstable-options

You can then run examples from our docs:

cd ..
git clone git@github.com:EnzymeAD/rustbook.git  
cd rustbook/samples
RUSTFLAGS="-Zautodiff=Enable" cargo +enzyme test reverse

Autodiff is still experimental, so if you want to use it in your own projects, you will need to add lto="fat" to your Cargo.toml and use RUSTFLAGS="-Zautodiff=Enable" cargo +enzyme instead of cargo or cargo +nightly.

Compiler Explorer and dist builds

Our compiler explorer instance can be updated to a newer rustc in a similar way. First, prepare a docker instance.

docker run -it ubuntu:22.04
export CC=clang CXX=clang++
apt update
apt install wget vim python3 git curl libssl-dev pkg-config lld ninja-build cmake clang build-essential 

Then build rustc in a slightly altered way:

git clone --depth=1 https://github.com/EnzymeAD/rust.git
cd rust
./configure --enable-llvm-link-shared --enable-llvm-plugins --enable-llvm-enzyme --release-channel=nightly --enable-llvm-assertions --enable-clang --enable-lld --enable-option-checking --enable-ninja --disable-docs
./x dist

We then copy the tarball to our host. The dockerid is the newest entry under docker ps -a.

docker cp <dockerid>:/rust/build/dist/rust-nightly-x86_64-unknown-linux-gnu.tar.gz rust-nightly-x86_64-unknown-linux-gnu.tar.gz

Afterwards we can create a new (pre-release) tag on the EnzymeAD/rust repository and make a PR against the EnzymeAD/enzyme-explorer repository to update the tag. Remember to ping tgymnich on the PR to run his update script.

Build instruction for Enzyme itself

Following the Rust build instruction above will build LLVMEnzyme, LLDEnzyme, and ClangEnzyme along with the Rust compiler. We recommend that approach, if you just want to use any of them and have no experience with cmake. However, if you prefer to just build Enzyme without Rust, then these instructions might help.

git clone --depth=1 git@github.com:llvm/llvm-project.git 
cd llvm-project
mkdir build
cd build
cmake -G Ninja ../llvm -DLLVM_TARGETS_TO_BUILD="host" -DLLVM_ENABLE_ASSERTIONS=ON -DLLVM_ENABLE_PROJECTS="clang;lld" -DLLVM_ENABLE_RUNTIMES="openmp" -DLLVM_ENABLE_PLUGINS=ON -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=.
ninja
ninja install

This gives you a working LLVM build, now we can continue with building Enzyme. Leave the llvm-project folder, and execute the following commands:

git clone git@github.com:EnzymeAD/Enzyme.git 
cd Enzyme/enzyme
mkdir build 
cd build 
cmake .. -G Ninja -DLLVM_DIR=<YourLocalPath>/llvm-project/build/lib/cmake/llvm/ -DLLVM_EXTERNAL_LIT=<YourLocalPath>/llvm-project/llvm/utils/lit/lit.py -DCMAKE_BUILD_TYPE=Release -DCMAKE_EXPORT_COMPILE_COMMANDS=YES -DBUILD_SHARED_LIBS=ON
ninja

This will build Enzyme, and you can find it in Enzyme/enzyme/build/lib/<LLD/Clang/LLVM>Enzyme.so. (Endings might differ based on your OS).