We cache initial `rustc --version` invocations, to speed up noop builds.
We check the mtime of `rustc` to bust the cache if the complier changed.
However, before this PR, we didn't look at mtimes of `RUSTC_WRAPPER` /
`RUSTC_WORKSPACE_WRAPPER`, so we could've re-use old cache with new
wrapper.
This commit is the Cargo half of support necessary for
rust-lang/rust#70458. Today the compiler emits embedded bytecode in
rlibs by default, but compresses it. This is both extraneous disk space
and wasted build time for almost all builds, so the PR in question there
is changing rustc to have a `-Cembed-bitcode` flag which, when enabled,
places the bitcode in the object file rather than an auxiliary file (no
extra compression), but also enables `-Cembed-bitcode=no` to disable
bitcode emission entirely.
This Cargo support changes Cargo to pass `-Cembed-bitcode=no` for almost
all compilations. Cargo will keep `lto = true` and such working by not
passing this flag (and thus allowing bitcode to get embedded), but by
default `cargo build` and `cargo build --release` will no longer have
any bitcode in rlibs which should result in speedier builds!
Most of the changes here were around the test suite and various
assertions about the `rustc` command lines we spit out. One test was
hard-disabled until we can get `-Cembed-bitcode=no` into nightly, and
then we can make it a nightly-only test. The test will then be stable
again once `-Cembed-bitcode=no` hits stable.
Note that this is intended to land before the upstream `-Cembed-bitcode`
change. The thinking is that we'll land everything in rust-lang/rust all
at once so there's no build time regressions for anyone. If we were to
land the `-Cembed-bitcode` PR first then there would be a build time
regression until we land Cargo changes because rustc would be emitting
uncompressed bitcode by default and Cargo wouldn't be turning it off.
This commit enables pipelined compilation by default in Cargo now that
the requisite support has been stablized in rust-lang/rust#62766. This
involved minor updates in a number of locations here and there, but
nothing of meat has changed from the original implementation (just
tweaks to how rustc is called).
* Collapse the nested cargotest::support module into the cargotest
module (merge the mod.rs's)
* Rename the cargotest module to support
* Nest the top-level hamcrest module into support
By rewriting the tests, with rerast (https://github.com/google/rerast),
to use the newly introduced "at" method.
First I added the following temporary function to cargotest::support:
pub fn project_foo() -> ProjectBuilder {
project("foo")
}
Then I defined the following rewrite.rs:
use cargotest::support::{ project, project_foo };
fn rule1(a: &'static str) {
replace!(project("foo") => project_foo());
replace!(project(a) => project_foo().at(a));
}
Then I ran rerast:
cargo +nightly rerast --rules_file=rewrite.rs --force --targets tests --file tests/testsuite/main.rs
Finally I searched and replaced the references to project_foo with
argument-less project (a little awkardly on macOS with a git clean).
find tests -type f -exec sed -i -e 's/project_foo/project/g' {} +
git clean -d tests
