AdaWebPack

AdaWebPack includes GNAT-LLVM compiler for WebAssembly target, GNAT Run Time Library and AdaWebPack bindings for Web API.

How to install

Prebuild packages are available on Release page.

You will also need wasm-ld, the Web asssembly linker. You will find this:

• on Fedora Linux through the lld package;
• on Ubuntu through the lld-16 package;
• on other Linux systems look for a similarly-named package.

How to build

• Setup GNAT using Alire.

• Clone GNAT-LLVM. Latest known good revision of GNAT-LLVM compatible with GNAT FSF is 66e36d929524972353600db5d604d0189cf0308f.

  git clone https://github.com/AdaCore/gnat-llvm
  git -C gnat-llvm checkout 66e36d929524972353600db5d604d0189cf0308f
  

• Clone bb-runtimes. Use gnat-fsf-14 branch.

  git clone -b gnat-fsf-14 https://github.com/Fabien-Chouteau/bb-runtimes gnat-llvm/llvm-interface/bb-runtimes
  

• Clone GCC sources. Use, for instance, releases/gcc-14.1.0 commit.

  git clone --single-branch --branch=releases/gcc-14 --shallow-since=01-04-2024 https://github.com/gcc-mirror/gcc gnat-llvm/llvm-interface/gcc
  git -C gnat-llvm/llvm-interface/gcc checkout releases/gcc-14.1.0
  

• Setup GNAT-LLVM development environment, see details in GNAT-LLVM README. Note, you need to use externally build LLVM with enabled 'lld' project and 'WebAssembly' target, so, if you build it your-self, cmake command line should contain among other switches:

  cmake ... -DLLVM_ENABLE_PROJECTS='...;clang;lld' -DLLVM_TARGETS_TO_BUILD="...;WebAssembly"
  

  On Ubuntu it is possible to install prebuild LLVM/CLang packages (use LLVM/CLang 16). However, alternatives need to be updated using the provided script:

  sudo utilities/update-alternatives-clang.sh 16 100
  

  Or install a LLVM 16 binary release (llvm-16, lld-16 and clang-16 are required).

• Checkout AdaWebPack repository into gnat-llvm/llvm-interface as adawebpack_src and create link for Makefile.target.

  cd gnat-llvm/llvm-interface
  git clone https://github.com/godunko/adawebpack.git adawebpack_src
  ln -s adawebpack_src/source/rtl/Makefile.target
  cd -
  

• Create a link to RTS source code

  cd gnat-llvm/llvm-interface
  ln -s bb-runtimes/gnat_rts_sources/include/rts-sources/
  cd -
  

• Create a link to GNAT source code (or copy it)

  cd gnat-llvm/llvm-interface
  ln -s gcc/gcc/ada gnat_src
  cd -
  

• Apply patch to GNAT-LLVM repository

  cd gnat-llvm/llvm-interface
  patch -p1 < adawebpack_src/patches/gnat-llvm.patch
  patch -p1 < adawebpack_src/patches/llvm_wrapper2.patch
  cd -
  

• Use make wasm to build compiler and Run Time Library

  cd gnat-llvm/llvm-interface
  make wasm
  cd -
  

• When make finishes, you will find toolchain in gnat-llvm/llvm-interface/bin.

  cd gnat-llvm/llvm-interface
  export PATH=$PWD/bin:$PATH
  cd -
  

• Now you can build examples:

  cd gnat-llvm/llvm-interface/adawebpack_src
  make build_examples
  cd -
  

  You will most likely need to run the examples through an HTTP server; otherwise, the browser will report a security error and/or refuse to load the page. An easy way to obtain an HTTP server is by via Python 3 with python3 -m http.server.

Usage with Docker

It could be handy to use docker.

• Find latest build on our Fedora COPR repository.
• Build a container image (make sure to replace curl argument with latest RPM URL)

  docker build --tag wgprbuild - <<EOF
  FROM registry.fedoraproject.org/fedora-minimal:40
  RUN microdnf --assumeyes install \
    gprbuild \
    clang16 \
    llvm16 \
    lld \
    libgnat \
    ca-certificates && \
  curl -O \
  https://download.copr.fedorainfracloud.org/results/reznik/adawebpack/fedora-40-x86_64/07674186-adawebpack/adawebpack-24.0.0-git.fc40.x86_64.rpm && \
  rpm -i adawebpack*.rpm && \
  rm -f adawebpack*.rpm && \
  /usr/share/adawebpack/update-alternatives-clang.sh 16 99 && \
  microdnf clean all
  EOF
  

• Write a bash wrapper script to replace gprbuild like this:

  #!/bin/bash
  exec docker run --rm --tmpfs /tmp/ --user $UID --volume $HOME:$HOME --workdir $PWD wgprbuild gprbuild "$@"
  

Unsupported features

• nested subprograms are not supported

• exceptions support is limited to local exceptions propagation and last chance handler

• tasks and protected objects are not supported

License

Web API bindings is licensed under BSD3 license.

GNAT Runtime Library is licensed under GPL3 license with GCC Runtime Library Exception.