This repository contains no compiler or library code itself; it uses git submodules to pull in the upstream Clang and LLVM tree, as well as the wasi-libc tree.
The libc portion of this SDK is the wasi-libc.
Upstream Clang and LLVM (from 9.0 onwards) can compile for WASI out of the box, and WebAssembly support is included in them by default. So, all that's done here is to provide builds configured to set the default target and sysroot for convenience.
One could also use a standard Clang installation, build a sysroot from the sources mentioned above, and compile with "--target=wasm32-wasi --sysroot=/path/to/sysroot".
This repository uses git submodule, to clone it you need use the command below :
git clone --recursive https://github.com/WebAssembly/wasi-sdk.gitThe Wasm-sdk's build process needs some packages :
cmakeclangninja
Please refer to your OS documentation to install those packages.
To build the full package:
cd wasi-sdk
NINJA_FLAGS=-v make packageThe built package can be found into dist directory. For releasing a new
version of the package on GitHub, see RELEASING.md.
A typical installation from the release binaries might look like the following:
export WASI_VERSION=14
export WASI_VERSION_FULL=${WASI_VERSION}.0
wget https://github.com/WebAssembly/wasi-sdk/releases/download/wasi-sdk-${WASI_VERSION}/wasi-sdk-${WASI_VERSION_FULL}-linux.tar.gz
tar xvf wasi-sdk-${WASI_VERSION_FULL}-linux.tar.gzUse the clang installed in the wasi-sdk directory:
export WASI_SDK_PATH=`pwd`/wasi-sdk-${WASI_VERSION_FULL}
CC="${WASI_SDK_PATH}/bin/clang --sysroot=${WASI_SDK_PATH}/share/wasi-sysroot"
$CC foo.c -o foo.wasmNote: ${WASI_SDK_PATH}/share/wasi-sysroot contains the WASI-specific
includes/libraries/etc. The --sysroot=... option is not necessary if
WASI_SDK_PATH is /opt/wasi-sdk.
Autoconf 2.70 now recognizes WASI.
For convenience when building packages that aren't yet updated, updated
config.sub and config.guess files are installed at share/misc/config.*
in the install directory.
We provide a docker image including wasi-sdk that can be used for building projects without a separate installation of the SDK. Autotools, CMake, and Ninja are included in this image, and standard environment variables are set to use wask-sdk for building.
For example, this command can build a make-based project with the Docker image.
docker run -v `pwd`:/src -w /src ghcr.io/webassembly/wasi-sdk make
Take note of the notable limitations below when building projects, for example many projects will need threads support disabled in a configure step before building with wasi-sdk.
This repository does not yet support C++ exceptions. C++ code is supported only with -fno-exceptions for now. Similarly, there is not yet support for setjmp/longjmp. Work on support for exception handling is underway at the language level which will support both of these features.
This repository does not yet support threads. Specifically, WASI does not yet have an API for creating and managing threads yet, and WASI libc does not yet have pthread support.
This repository does not yet support dynamic libraries. While there are some efforts to design a system for dynamic libraries in wasm, it is still in development and not yet generally usable.
There is no support for networking. It is a goal of WASI to support networking in the future though.