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Motiejus Jakštys 2021-12-22 10:46:49 +02:00
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@ -3,7 +3,7 @@
# Bazel zig cc toolchain
This is a C/C++ toolchain that can (cross-)compile C/C++ programs. It contains
clang-13, musl, glibc (versions 2-2.33, selectable), all in a ~40MB package.
clang-13, musl, glibc (versions 2-2.34, selectable), all in a ~40MB package.
Read
[here](https://andrewkelley.me/post/zig-cc-powerful-drop-in-replacement-gcc-clang.html)
about zig-cc; the rest of the README will present how to use this toolchain
@ -54,13 +54,46 @@ used, run:
$ bazel query @zig_sdk//... | sed -En '/.*_toolchain$/ s/.*:(.*)_toolchain$/\1/p'
```
## Compiling OS X executables
# Known Issues in bazel-zig-cc
MacOS SDK (`--sysroot`) may be necessary. Read [Jakub's comment][sysroot] about
it. This section will be expanded once yours truly understands more about the
requirements and limitations of linking on OSX.
These are the things you may stumble into when using bazel-zig-cc. I am
unlikely to implement them, but patches implementing those will be accepted.
See [Questions & Contributions](#questions-amp-contributions) on how to
contribute.
# Known Issues
## OSX: sysroot
MacOS SDK (`--sysroot`) may be necessary for non-trivial programs (and is
required for all cgo darwin/arm64 ones). Read [Jakub's comment][sysroot] about
it. Support for OSX sysroot is currently not implemented.
## OSX: different OS targets (Catalina -- Monterey)
Since [zig 0.9.0](https://ziglang.org/download/0.9.0/release-notes.html#macOS)
zig may target macos.10 (Catalina), macos.11 (Big Sur) or macos.12 (Monterey).
It currently targets the lowest version.
## Zig cache
Currently zig cache is in `$HOME` so `bazel clean --expunge` does not clear the
zig cache. Zig's cache should be stored somewhere in the project's path.
## Alternative download URLs
Currently zig is downloaded from [dl.jakstys.lt](https://dl.jakstys.lt/zig/),
which is nuts. One should provide a way to specify alternative URLs for the zig
toolchain.
## Bazel toolchain target locations
The path to Bazel toolchains is `@zig_sdk//:<toolchain>_toolchain`. It should
be moved to `@zig_sdk//toolchain:<toolchain>` or similar; so the user-facing
targets are in their own namespace.
# Known Issues in upstream
This section lists issues that I've stumbled into when using `zig cc`, and
is outside of control bazel-zig-cc's control.
## using glibc 2.27 or older
@ -72,7 +105,7 @@ Background: when glibc 2.27 or older is selected, it may miss `fcntl64`. A
workaround is applied for `x86_64`, but not for aarch64. The same workaround
may apply to aarch64, but the author didn't find a need to test it (yet).
# Closed issues
# Closed upstream issues
- [ziglang/zig misplaced relocated glibc stubs (pthread_sigmask) #7667](https://github.com/ziglang/zig/issues/7667) (CLOSED, thanks mjonaitis and andrewrk)
- [ziglang/zig macho: fail if requested -framework is not found #10312](https://github.com/ziglang/zig/pull/10312) (CLOSED, thanks kubkon)
@ -134,15 +167,6 @@ how CI does it.
This section lists things that I think will happen at some point: either by
myself, or my colleagues, or outside contributors.
* Move Zig cache path to bazel root, so `bazel clean --expunge` clears the zig
cache.
* Provide a way to specify alternative URLs for the zig toolchain (currently
zig is downloaded from jakstys.lt, which is nuts).
* Rename `@zig_sdk//:<toolchain>_toolchain` to
`@zig_sdk//toolchain:<toolchain>` or similar; so the user-facing targets are
in their own namespace.
* Provide a way to specify sysroot for Darwin (OSX). See [#Compiling OS X
executables](#compiling-os-x-executables) for an ongoing discussion.
# Questions & Contributions