update to literal-escaper 0.0.4 for better API without `unreachable` and faster string parsing
This is the replacement for just the part of https://github.com/rust-lang/rust/pull/138163 dealing with the changed API of unescape functionality, since that got moved into its own crate.
<del>This uses an unpublished version of literal-escaper (https://github.com/rust-lang/literal-escaper/pull/8).</del>
r? `@nnethercote`
The panic_abort crate must be compiled with panic=abort, but cargo
doesn't allow setting the panic strategy for a single crate the usual
way using panic="abort", but luckily per-package rustflags do allow
this. Bootstrap previously handled this in its rustc wrapper, but for
example the build systems of cg_clif and cg_gcc don't use the rustc
wrapper, so they would either need to add one, patch the standard
library or be unable to build a sysroot suitable for both panic=abort
and panic=unwind (as is currently the case).
Many of `std`'s dependency have a dependency on the crates.io
`compiler-builtins` when used with the feature
`rustc-std-workspace-core`. Use a Cargo patch to select the in-tree
version instead.
`compiler-builtins` is also added as a dependency of
`rustc-std-workspace-core` so these crates can remove their crates.io
dependency in the future.
Fixes
```
Checking stage0 library artifacts {alloc, core, panic_abort, panic_unwind, proc_macro, std, sysroot, test, unwind} (x86_64-unknown-linux-gnu)
warning: profile package spec `adler` in profile `release` did not match any packages
Did you mean `adler2`?
```
Apply size optimizations to panic machinery and some cold functions
* std dependencies gimli and addr2line are now built with opt-level=s
* various panic-related methods and `#[cold]` methods are now marked `#[optimize(size)]`
Panics should be cold enough that it doesn't make sense to optimize them for speed. The only tradeoff here is if someone does a lot of backtrace captures (without panics) and printing then the opt-level change might impact their perf.
Seems to be the first use of the optimize attribute. Tracking issue #54882
This ensures that the Cargo.lock packaged for it in the rust-src
component is up-to-date, allowing rust-analyzer to run cargo metadata on
the standard library even when the rust-src component is stored in a
read-only location as is necessary for loading crates.io dependencies of
the standard library.
This also simplifies tidy's license check for runtime dependencies as it
can now look at all entries in library/Cargo.lock without having to
filter for just the dependencies of runtime crates. In addition this
allows removing an exception in check_runtime_license_exceptions that
was necessary due to the compiler enabling a feature on the object crate
which pulls in a dependency not allowed for the standard library.
While cargo workspaces normally enable dependencies of multiple targets
to be reused, for the standard library we do not want this reusing to
prevent conflicts between dependencies of the sysroot and of tools that
are built using this sysroot. For this reason we already use an unstable
cargo feature to ensure that any dependencies which would otherwise be
shared get a different -Cmetadata argument as well as using separate
build dirs.
This doesn't change the situation around vendoring. We already have
several cargo workspaces that need to be vendored. Adding another one
doesn't change much.
There are also no cargo profiles that are shared between the root
workspace and the library workspace anyway, so it doesn't add any extra
work when changing cargo profiles.
