Each of `{D,Subd}iagnosticMessage::{Str,Eager}` has a comment:
```
// FIXME(davidtwco): can a `Cow<'static, str>` be used here?
```
This commit answers that question in the affirmative. It's not the most
compelling change ever, but it might be worth merging.
This requires changing the `impl<'a> From<&'a str>` impls to `impl
From<&'static str>`, which involves a bunch of knock-on changes that
require/result in call sites being a little more precise about exactly
what kind of string they use to create errors, and not just `&str`. This
will result in fewer unnecessary allocations, though this will not have
any notable perf effects given that these are error paths.
Note that I was lazy within Clippy, using `to_string` in a few places to
preserve the existing string imprecision. I could have used `impl
Into<{D,Subd}iagnosticMessage>` in various places as is done in the
compiler, but that would have required changes to *many* call sites
(mostly changing `&format("...")` to `format!("...")`) which didn't seem
worthwhile.
Fluent, with all the icu4x it brings in, takes quite some time to
compile. `fluent_messages!` is only needed in further downstream rustc
crates, but is blocking more upstream crates like `rustc_index`. By
splitting it out, we allow `rustc_macros` to be compiled earlier, which
speeds up `x check compiler` by about 5 seconds (and even more after the
needless dependency on `serde_json` is removed from
`rustc_data_structures`).
Nils had an excellent idea the other day: the same way that rustdoc is
able to load `rustc_driver` from the sysroot, ui-fulldeps tests should
also be able to load it from the sysroot. That allows us to run fulldeps
tests with stage1, without having to fully rebuild the compiler twice.
It does unfortunately have the downside that we're running the tests on
the *bootstrap* compiler, not the in-tree sources, but since most of the
fulldeps tests are for the *API* of the compiler, that seems ok.
I think it's possible to extend this to `run-make-fulldeps`, but I've
run out of energy for tonight.
- Move `plugin` tests into a subdirectory.
Plugins are loaded at runtime with `dlopen` and so require the ABI of
the running compile to match the ABI of the compiler linked with
`rustc_driver`. As a result they can't be supported in stage 1 and have
to use `// ignore-stage1`.
- Remove `ignore-stage1` from most non-plugin tests
- Ignore diagnostic tests in stage 1. Even though this requires a stage
2 build to load rustc_driver, it's primarily testing the error message
that the *running* compiler emits when the diagnostic struct is malformed.
- Pass `-Zforce-unstable-if-unmarked` in stage1, not just stage2. That
allows running `hash-stable-is-unstable` in stage1, since it now
suggests adding `rustc_private` to enable loading the crates.
- Add libLLVM.so to the stage0 target sysroot, to allow fulldeps tests
that act as custom drivers to load it at runtime.
- Pass `--sysroot stage0-sysroot` in compiletest so that we use the
correct version of std.
Instead of loading the Fluent resources for every crate in
`rustc_error_messages`, each crate generates typed identifiers for its
own diagnostics and creates a static which are pulled together in the
`rustc_driver` crate and provided to the diagnostic emitter.
Signed-off-by: David Wood <david.wood@huawei.com>
