This commit fixes an issue in Cargo where when an entire project
directory is renamed (preserving the target directory) then path
dependencies with build scripts would have their build scripts rereun
when building again. The problem with this was that when a build script
doesn't print `rerun-if-changed` Cargo's conservative fingerprint listed
an absolute path in it, which was intended to be a relative path.
The fix here is to use a relative path in the fingerprint to ensure that
it's not the reason a rebuild happens when directories are renamed.
This commit updates Cargo's parsing of rustc's dep-info files to account
for changes made upstream in rust-lang/rust#71858. This means that if
`env!` or `option_env!` is used in crate files Cargo will correctly
rebuild the crate if the env var changes.
Closes#8417
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 is a moral revert of #6503 but not a literal code revert. This
switches Cargo's behavior to avoid hashing compiler flags into
`-Cmetadata` since we've now had multiple requests of excluding flags
from the `-Cmetadata` hash: usage of `--remap-path-prefix` and PGO
options. These options should only affect how the compiler is
invoked/compiled and not radical changes such as symbol names, but
symbol names are changed based on `-Cmetadata`. Instead Cargo will still
track these flags internally, but only for reinvoking rustc, and not for
caching separately based on rustc flags.
Closes#7416
Build script updates during execution can change the memoized hash of a
`Fingerprint`, and while previously we cleared out a single build
script's memoized hash we forgot to clear out everything that depended
on it as well. This commit pessimistically clears out all `Fingerprint`
memoized hashes just before building to ensure that during the build
everything has the most up-to-date view of the world, and when build
scripts change fingerprints everything that depends on them won't have
run yet.
Closes#7362
Now that the `mtime` of intermediate artifacts is not updated there's no need
for this test anymore (it now fails because without the `mtime`s it cannot
perform the intended GC operation).
