> **Note**: this PR is me weaving together the work of many others. For
example @yerzham's and @cpetig's work on #565 pretty much shaped this
PR. Thank you!
This commit adds initial configuration support for building wasi-sdk
with support for C++ exceptions in WebAssembly. A small test is included
which is exercised in CI at this time, but otherwise this does not
update CI to actually ship sdk builds with C++ exceptions enabled.
Instead the intention here is to make it easier to test builds with
support for C++ exceptions and centralize planning/development around
this.
The goal here is to get things compiling to the point that applications
can be compiled. I haven't thoroughly tested C++ exceptions and as
evident in this PR it still requires changes in LLVM. Some small logic
is added here to apply a `*.patch` file to LLVM to avoid needing a new
submodule fork or waiting for upstream changes. The intention is that
this `*.patch` is short-lived once the changes are officially merged
into LLVM itself.
The `*.patch` included here contains llvm/llvm-project#168449 as well as
another minor edit I found was necessary to get things compiling
locally. Given the discussion on that PR it looks like once LLVM is
updated with that merged the extra part of the `*.patch` won't be
necessary.
This PR notably does not enable shared libraries when exceptions are
enabled. I don't know enough about how things are supposed to work to be
able to fully diagnose the compilation errors I'm seeing if shared
libraries are enabled. This is something I'd hope would be fixed before
actually shipping exceptions support.
This PR then additionally folds in [this gist][gist] for various bits of
build logic to this repository itself.
Finally, this PR includes some documentation about the current status of
exceptions and links to various tracking issues too.
[gist]: https://gist.github.com/yerzham/302efcec6a2e82c1e8de4aed576ea29d
This updates to include WebAssembly/wasi-libc#709 and then additionally
configures wasi-libc with `-DWASI_SDK_VERSION=...` to ensure that
wasi-sdk builds will now have `__wasi_sdk_major__` defined along with
`__wasi_sdk_version__`.
ClosesWebAssembly/wasi-libc#688
In componentize-py Joel's building custom wasi-sdk binaries for more
Linux compat which is what maturin, the build tool use there, desires. I
don't think there's a concrete reason to have a higher Linux version
here, so let's lower it in wasi-sdk itself.
This commit switches the build container from Ubuntu 20.04 (glibc 2.31)
to AlmaLinux 8 (glibc 2.28). The AlmaLinux container is what Wasmtime
uses, for example, and has supported security updates to 2029 and is I
believe intended to be used for purposes such as this.
This commit updates the build of the `wasm32-wasip2` target to always
pass `-fPIC` to compilation of wasi-libc. This notably enables using
`libc.a` in dynamic linking situations instead of being forced to use
`libc.so`. While many applications likely want to use `libc.so` I've
found it more flexible if objects are compatible with as many builds as
possible. This will enable, for example, building shared libraries in
Rust by default since Rust only ships `libc.a`, not `libc.so`, in the
pre-built sysroot. This behavior additionally matches the Rust
`wasm32-wasip2` target where `-fPIC` is enabled by default there.
* Provide flags for emitting the standard exception-handling
instructions.
* More further explain what flags are doing.
* Show a sample program that can be compiled both ways.
* Delegate running in a runtime to various runtimes, so remove the "run
the program" documentation here.
* Remove `wasm-opt` documentation since it's now documented how to emit
the standard instructions directly with LLVM.
This bit me while releasing wasi-sdk-26/27 because while I tried to get
both builds going at once they overlapped in their key meaning that they
had to progress one-at-a-time. This uses `github.ref` instead of the PR
number which I think should be more robust in situations like this.
Add a cmake option WASI_SDK_CPU_CFLAGS to specify CFLAGS to control wasm
features to enable/disable.
Make the default `-mcpu=lime1`.
Comparing to the default "generic" target of the recent llvm, this
effectively
* disables reference-types and bulk-memory (enable their partial
counterparts instead)
* enables extended-const
Note: as of writing this, a few popular runtimes, including wasm3 and
wasm-micro-runtime,
don't support extented-const yet.
Note: regardless of this, wasi-libc enables necessary features for
certain files. (bulk-memory and exception-handling)
cf. https://github.com/WebAssembly/wasi-sdk/issues/525
References:
https://github.com/WebAssembly/tool-conventions/blob/main/Lime.mdhttps://github.com/bytecodealliance/wasm-micro-runtime/issues/4272
This commit enables thread support in libc++ for all thread models,
enabling C++ applications that use threading APIs like `<atomic>` but do
not spawn threads (e.g. Clang) to be built with minimal changes.
Fixes#546.
Depends on WebAssembly/wasi-libc#602.
Update from LLVM 20.1.1 to 20.1.8. This release contains various bug
fixes and notably for wasi-sdk includes llvm/llvm-project#146574, which
fixes inline asm vector operands.
`wasi-sdk` releases have always been a bit ad hoc, but after discussing
#536 we all agreed some regularity would be helpful; let's see what we
think of a 3-month cadence.
This change allows us to have per-target libclang_rt.* libraries instead
of per-OS. This is particularly required for w/threads and wo/threads
targets, whose rt libraries could be incompatible even with the same OS
string.
This change starts building `compiler-rt` for w/threads and wo/threads
separately, so that we can enable thread-related features for p1-threads
target for building upcoming ASan clang_rt libraries. Also
`COMPILER_RT_OS_DIR` is not set anymore as it's unused when
`LLVM_ENABLE_PER_TARGET_RUNTIME_DIR` is enabled.
Sy Brand
Alex Crichton
Roman Volosatovs
Nis Meinert
Tim Chevalier
Catherine
YAMAMOTO Takashi
Dan Gohman
Andrew Brown
Yuta Saito