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.

godunko / adawebpack