This commit adds support for sccache, a ccache-like compiler which works on MSVC
and stores results into an S3 bucket. This also switches over all Travis and
AppVeyor automation to using sccache to ensure a shared and unified cache over
time which can be shared across builders.
The support for sccache manifests as a new `--enable-sccache` option which
instructs us to configure LLVM differently to use a 'sccache' binary instead of
a 'ccache' binary. All docker images for Travis builds are updated to download
Mozilla's tooltool builds of sccache onto various containers and systems.
Additionally a new `rust-lang-ci-sccache` bucket is configured to hold all of
our ccache goodies.
This commit switches the default build system for Rust from the makefiles to
rustbuild. The rustbuild build system has been in development for almost a year
now and has become quite mature over time. This commit is an implementation of
the proposal on [internals] which slates deletion of the makefiles on
2016-01-02.
[internals]: https://internals.rust-lang.org/t/proposal-for-promoting-rustbuild-to-official-status/4368
This commit also updates various documentation in `README.md`,
`CONTRIBUTING.md`, `src/bootstrap/README.md`, and throughout the source code of
rustbuild itself.
Closes#37858
The previous panic message delivered when a musl target was specified
but musl-root was not specified incorrectly instructed the user to add
the musl-root key to the "build" section of config.toml. The key
actually needs to be added to the "rust" section.
This is a hack to support building targets that don't support jemalloc
alongside hosts that do. The jemalloc build is controlled by a feature
of the std crate, and if that feature changes between targets, it
invalidates the fingerprint of std's build script (this is a cargo
bug); so we must ensure that the feature set used by std is the same
across all targets, which means we have to build the alloc_jemalloc
crate for targets like emscripten, even if we don't use it.
config.toml now accepts a target.$TARGET.musl-root key that lets you
override the "build" musl-root value, which is set via the --musl-root
flag or via the build.musl-root key.
With this change, it's now possible to compile std for several musl
targets at once. Here's are the sample commands to do such thing:
```
$ configure \
--enable-rustbuild \
--target=x86_64-unknown-linux-musl,arm-unknown-linux-musleabi \
--musl-root=/musl/x86_64-unknown-linux-musl/
$ edit config.toml && tail config.toml
[target.arm-unknown-linux-musleabi]
musl-root = "/x-tools/arm-unknown-linux-musleabi/arm-unknown-linux-musleabi/sysroot/usr"
$ make
```
The targets are:
- `arm-unknown-linux-musleabi`
- `arm-unknown-linux-musleabihf`
- `armv7-unknown-linux-musleabihf`
These mirror the existing `gnueabi` targets.
All of these targets produce fully static binaries, similar to the
x86 MUSL targets.
For now these targets can only be used with `--rustbuild` builds, as
https://github.com/rust-lang/compiler-rt/pull/22 only made the
necessary compiler-rt changes in the CMake configs, not the plain
GNU Make configs.
I've tested these targets GCC 5.3.0 compiled again musl-1.1.12
(downloaded from http://musl.codu.org/). An example `./configure`
invocation is:
```
./configure \
--enable-rustbuild
--target=arm-unknown-linux-musleabi \
--musl-root="$MUSL_ROOT"
```
where `MUSL_ROOT` points to the `arm-linux-musleabi` prefix.
Usually that path will be of the form
`/foobar/arm-linux-musleabi/arm-linux-musleabi`.
Usually the cross-compile toolchain will live under
`/foobar/arm-linux-musleabi/bin`. That path should either by added
to your `PATH` variable, or you should add a section to your
`config.toml` as follows:
```
[target.arm-unknown-linux-musleabi]
cc = "/foobar/arm-linux-musleabi/bin/arm-linux-musleabi-gcc"
cxx = "/foobar/arm-linux-musleabi/bin/arm-linux-musleabi-g++"
```
As a prerequisite you'll also have to put a cross-compiled static
`libunwind.a` library in `$MUSL_ROOT/lib`. This is similar to [how
the x86_64 MUSL targets are built]
(https://doc.rust-lang.org/book/advanced-linking.html).
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/`.
