This is an attempt to balance three problems, each of which would
be violated by a simpler implementation:
- A type alias should show all the `impl` blocks for the target
type, and vice versa, if they're applicable. If nothing was
done, and rustdoc continues to match them up in HIR, this
would not work.
- Copying the target type's docs into its aliases' HTML pages
directly causes far too much redundant HTML text to be generated
when a crate has large numbers of methods and large numbers
of type aliases.
- Using JavaScript exclusively for type alias impl docs would
be a functional regression, and could make some docs very hard
to find for non-JS readers.
- Making sure that only applicable docs are show in the
resulting page requires a type checkers. Do not reimplement
the type checker in JavaScript.
So, to make it work, rustdoc stashes these type-alias-inlined docs
in a JSONP "database-lite". The file is generated in `write_shared.rs`,
included in a `<script>` tag added in `print_item.rs`, and `main.js`
takes care of patching the additional docs into the DOM.
The format of `trait.impl` and `type.impl` JS files are superficially
similar. Each line, except the JSONP wrapper itself, belongs to a crate,
and they are otherwise separate (rustdoc should be idempotent). The
"meat" of the file is HTML strings, so the frontend code is very simple.
Links are relative to the doc root, though, so the frontend needs to fix
that up, and inlined docs can reuse these files.
However, there are a few differences, caused by the sophisticated
features that type aliases have. Consider this crate graph:
```text
---------------------------------
| crate A: struct Foo<T> |
| type Bar = Foo<i32> |
| impl X for Foo<i8> |
| impl Y for Foo<i32> |
---------------------------------
|
----------------------------------
| crate B: type Baz = A::Foo<i8> |
| type Xyy = A::Foo<i8> |
| impl Z for Xyy |
----------------------------------
```
The type.impl/A/struct.Foo.js JS file has a structure kinda like this:
```js
JSONP({
"A": [["impl Y for Foo<i32>", "Y", "A::Bar"]],
"B": [["impl X for Foo<i8>", "X", "B::Baz", "B::Xyy"], ["impl Z for Xyy", "Z", "B::Baz"]],
});
```
When the type.impl file is loaded, only the current crate's docs are
actually used. The main reason to bundle them together is that there's
enough duplication in them for DEFLATE to remove the redundancy.
The contents of a crate are a list of impl blocks, themselves
represented as lists. The first item in the sublist is the HTML block,
the second item is the name of the trait (which goes in the sidebar),
and all others are the names of type aliases that successfully match.
This way:
- There's no need to generate these files for types that have no aliases
in the current crate. If a dependent crate makes a type alias, it'll
take care of generating its own docs.
- There's no need to reimplement parts of the type checker in
JavaScript. The Rust backend does the checking, and includes its
results in the file.
- Docs defined directly on the type alias are dropped directly in the
HTML by `render_assoc_items`, and are accessible without JavaScript.
The JSONP file will not list impl items that are known to be part
of the main HTML file already.
[JSONP]: https://en.wikipedia.org/wiki/JSONP
This is shorter, avoids potential conflicts with a crate
named `implementors`[^1], and will be less confusing when JS
include files are added for type aliases.
[^1]: AFAIK, this couldn't actually cause any problems right now,
but it's simpler just to make it impossible than relying on never
having a file named `trait.Foo.js` in the crate data area.
Use beta cargo in opt-dist
Using the new stage2 cargo caused issues when a backwards-incompatible change was made to cargo. This means that we won't be testing the LTO/1-CGU optimized cargo, but I don't think that's a big issue, as we primarily want to test the compiler.
Should fix [this](https://github.com/rust-lang/rust/pull/117000#issuecomment-1773639109) failure.
Rollup of 4 pull requests
Successful merges:
- #116985 (Use gdb.ValuePrinter tag class)
- #116989 (Skip test if Unix sockets are unsupported)
- #117034 (Don't crash on empty match in the `nonexhaustive_omitted_patterns` lint)
- #117037 (rustdoc book doc example error)
r? `@ghost`
`@rustbot` modify labels: rollup
rustdoc book doc example error
closes#117036
This is the minimal change required to make the second what-to-include.md example valid.
Another more modern solution could be considered:
```
/// Example
/// ```rust
/// let fortytwo = "42".parse::<u32>()?;
/// println!("{} + 10 = {}", fortytwo, fortytwo+10);
/// # Ok::<(), <u32 as std::str::FromStr>::Err>(())
/// ```
```
Use gdb.ValuePrinter tag class
GDB 14 has a "gdb.ValuePrinter" tag class that was introduced to let GDB evolve the pretty-printer API. Users of this tag are required to hide any local attributes or methods. This patch makes this change to the Rust pretty-printers. At present this is just a cleanup, providing the basis for any future changes.
ci: add a runner for vanilla LLVM 17
For CI cost, this can be seen as replacing the llvm-14 runner we dropped in #114148.
Also, I've set `IS_NOT_LATEST_LLVM` in the llvm-16 runner, since that's not the latest anymore.
Fix x86_64-gnu-llvm-15 CI tests
The CI script was broken - if there was a test failure in the first command chain (inside the `if`), CI would not report the failure.
It happened because there were two command chains separated by `&&` in the script, and since `set -e` doesn't exit for chained commands, if the first chain has failed, the script would happily continue forward, ignoring any test failures.
This could be fixed e.g. by adding some `|| exit 1` to the first chain, but I suppose that the `&&` chaining is unnecessary here anyway.
Reported [on Zulip](https://rust-lang.zulipchat.com/#narrow/stream/242791-t-infra/topic/test.20failure.20didn't.20stop.20CI).
Fixes: https://github.com/rust-lang/rust/issues/116867
Sync rustc_codegen_cranelift
The main highlights this time is new support for riscv64 linux enabled by a cranelift update. I have also updated some of the crates built as part of cg_clif's test suite which enabled removing several patches for them. And finally I have fixed a couple of tests in rustc's test suite with cg_clif.
r? `@ghost`
`@rustbot` label +A-codegen +A-cranelift +T-compiler +subtree-sync
Rollup of 7 pull requests
Successful merges:
- #116312 (Initiate the inner usage of `cfg_match` (Compiler))
- #116928 (fix bootstrap paths in triagebot.toml)
- #116955 (Updated README with expandable table of content.)
- #116981 (update the registers of csky target)
- #116992 (Mention the syntax for `use` on `mod foo;` if `foo` doesn't exist)
- #117026 (Fix broken link to Ayu theme in the rustdoc book)
- #117028 (Remove unnecessary `all` in Box)
r? `@ghost`
`@rustbot` modify labels: rollup
Mention the syntax for `use` on `mod foo;` if `foo` doesn't exist
Newcomers might get confused that `mod` is the only way of defining scopes, and that it can be used as if it were `use`.
Fix#69492.
coverage: Emit mappings for unused functions without generating stubs
For a while I've been annoyed by the fact that generating coverage maps for unused functions involves generating a stub function at the LLVM level.
As I suspected, generating that stub function isn't actually necessary, as long as we specifically tell LLVM about the symbol names of all the functions that have coverage mappings but weren't codegenned (due to being unused).
---
There is some helper code that gets moved around in the follow-up patches, so look at the first patch to see the most important functional changes.
---
`@rustbot` label +A-code-coverage
