A new target, `s390x-unknown-linux-gnu`, has been added to the compiler
and can be used to build no_core/no_std Rust programs.
Known limitations:
- librustc_trans/cabi_s390x.rs is missing. This means no support for
`extern "C" fn`.
- No support for this arch in libc. This means std can be cross compiled
for this target.
Disable gcc_personality_v0.c in rustbuild as well as the normal build.
Rustbuild now gets further on FreeBSD, but it still fails due to other problems.
The compiler-rt build system has been a never ending cause of pain for Rust
unfortunately:
* The build system is very difficult to invoke and configure to only build
compiler-rt, especially across platforms.
* The standard build system doesn't actually do what we want, not working for
some of our platforms and requiring a significant number of patches on our end
which are difficult to apply when updating compiler-rt.
* Compiling compiler-rt requires LLVM to be compiled, which... is a big
dependency! This also means that over time compiler-rt is not guaranteed to
build against older versions of LLVM (or newer versions), and we often want to
work with multiple versions of LLVM simultaneously.
The makefiles and rustbuild already know how to compile C code, the code here is
far from the *only* C code we're compiling. This patch jettisons all logic to
work with compiler-rt's build system and just goes straight to the source. We
just list all files manually (copied from compiler-rt's
lib/builtins/CMakeLists.txt) and compile them into an archive.
It's likely that this means we'll fail to pick up new files when we upgrade
compiler-rt, but that seems like a much less significant cost to pay than what
we're currently paying.
cc #34400, first steps towards that
The organization in rustbuild was a little odd at the moment where the `lib.rs`
was quite small but the binary `main.rs` was much larger. Unfortunately as well
there was a `build/` directory with the implementation of the build system, but
this directory was ignored by GitHub on the file-search prompt which was a
little annoying.
This commit reorganizes rustbuild slightly where all the library files (the
build system) is located directly inside of `src/bootstrap` and all the binaries
now live in `src/bootstrap/bin` (they're small). Hopefully this should allow
GitHub to index and allow navigating all the files while maintaining a
relatively similar layout to the other libraries in `src/`.
