Introduce Rust symbol mangling scheme.
This is an implementation of a "feature-complete" Rust mangling scheme, in the vein of rust-lang/rfcs#2603 ~~- but with some differences, see https://github.com/rust-lang/rfcs/pull/2603#issuecomment-458410463 for details~~ (@michaelwoerister integrated my proposed changes into the RFC itself).
On nightly, you can now control the mangling scheme with `-Z symbol-mangling-version`, which can be:
* `legacy`: the older mangling version, still the default currently
* `v0`: the new RFC mangling version, as implemented by this PR
To test the new mangling, set `RUSTFLAGS=-Zsymbol-mangling-version=v0` (or change [`rustflags` in `.cargo/config.toml`](https://doc.rust-lang.org/cargo/reference/config.html#configuration-keys)). Please note that only symbols from crates built with that flag will use the new mangling, and that tool support (e.g. debuggers) will be limited initially, and it may take a while for everything to be upstreamed. However, `RUST_BACKTRACE` should work out of the box with either mangling version.
<hr/>
The demangling implementation PR is https://github.com/alexcrichton/rustc-demangle/pull/23
~~(this PR already uses it via a git dependency, to allow testing)~~.
Discussion of the *design* of the mangling scheme should still happen on the RFC, but this PR's specific implementation details can be reviewed in parallel.
*Notes for reviewers*:
* ~~only the last 6 commits are specific to this branch, if necessary I can open a separate PR for everything else (it was meant to be its own small refactoring, but it got a bit out of hand)~~
~~based on #58140~~
* the "harness" commit is only there because it does some extra validation (comparing the demangling from `rustc-demangle` to the compiler's pretty-printing, adjusted slightly to produce the same output), that I would like to try on crater
* ~~there is the question of whether we should turn on the new mangling now, wait for tools to support it (I'm working on that), and/or have it under a `-Z` flag for now~~ (we're gating this on `-Z symbol-mangling-version=v0`, see above)
r? @nikomatsakis / @michaelwoerister cc @rust-lang/compiler
Migrate some books to mdbook version 0.2
There are 3 books still using old version but they need more effort so I hope to do them in subsequent PR if I find the time.
Swap order of `unsafe async fn` to `async unsafe fn`
Change the order of `unsafe async fn` to `async unsafe fn`.
I had intended to do this a while back but didn't get around to it...
This should be done because:
- It is the order used by `const unsafe fn` so therefore it is consistent.
- This keeps all the "effect/restriction" modifiers to the left of `unsafe` (which according to some is not an effect) instead of mixing them such that we are more forward compatible with some sort of effect system.
r? @cramertj
Speed up Azure CI installing Windows dependencies
There is known issue where PowerShell is unreasonably slow downloading
files due to an issue with rendering the progress bar, see this [issue](https://github.com/PowerShell/PowerShell/issues/2138)
That issue is fixed in PowerShell Core (available in Azure Pipelines as
pwsh.exe) but it can also be worked around by setting:
$ProgressPreference = 'SilentlyContinue'
I measured downloading LLVM and it took about 220s before, 5s after, so the improvement is significant.
error: remove StringError from Debug output
Seeing `StringError("something something")` in debug output can cause
someone to think there was an error dealing with `String`s, not that the
error type is just a string. So, remove that noise.
For example:
```
io error: Custom { kind: InvalidData, error: StringError("corrupt data") }
```
With this change:
```
io error: Custom { kind: InvalidData, error: "corrupt data" }
```
Make the `type_name` intrinsic deterministic
cc @eddyb for the printing infrastructure
cc @Centril for the deterministic (coherent?) output
r? @sfackler
ci: Favor SCRIPT instead of RUST_CHECK_TARGET
Since #61212 we've been timing out on OSX, and this looks to be because
we're building tools like Cargo and the RLS twice instead of once. This
turns out to be a slight bug in our configuration. CI builders using the
`RUST_CHECK_TARGET` directive actually execute `make all` just before
their acual target. In `make all` we're building a stage2 cargo, and
then in `make dist` we're building a stage1 cargo.
Other builders use `SCRIPT` which provides explicit control over what
`x.py` script, for example, is used to execute the build. This moves
almost all targets to using `SCRIPT` to ensure that we're explicitly
specifying what's being built where. Additionally this updates the logic
of `RUST_CHECK_TARGET` to remove the pre-flight tidy as well as the
pre-flight `make all`. The system LLVM builder (run on PRs) now
explicitly runs tidy first and then runs the rest of the test suite.
Avoid `hygiene_data` lookups
These commits mostly introduce compound operations that allow two close adjacent `hygiene_data` lookups to be combined.
r? @petrochenkov
