rustdoc: use JS to inline target type impl docs into alias
Preview docs:
- https://notriddle.com/rustdoc-html-demo-5/js-trait-alias/std/io/type.Result.html
- https://notriddle.com/rustdoc-html-demo-5/js-trait-alias-compiler/rustc_middle/ty/type.PolyTraitRef.html
This pull request also includes a bug fix for trait alias inlining across crates. This means more documentation is generated, and is why ripgrep runs slower (it's a thin wrapper on top of the `grep` crate, so 5% of its docs are now the Result type).
- Before, built with rustdoc 1.75.0-nightly (aa1a71e9e 2023-10-26), Result type alias method docs are missing: http://notriddle.com/rustdoc-html-demo-5/ripgrep-js-nightly/rg/type.Result.html
- After, built with this branch, all the methods on Result are shown: http://notriddle.com/rustdoc-html-demo-5/ripgrep-js-trait-alias/rg/type.Result.html
*Review note: This is mostly just reverting https://github.com/rust-lang/rust/pull/115201. The last commit has the new work in it.*
Fixes#115718
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
Remove `rustc_symbol_mangling/messages.ftl`.
It contains a single message that (a) doesn't contain any natural language, and (b) is only used in tests.
r? `@davidtwco`
Add method to convert internal to stable constructs
This is an alternative implementation to https://github.com/rust-lang/rust/pull/116999. I believe we can still improve the logic a bit here, but I wanted to see which direction we should go first.
In this implementation, the API is simpler and we keep Tables somewhat private. The definition is still public though, since we have to expose the Stable trait. However, there's a cost of keeping another thread-local and using `Rc`, but I'm hoping it will be a small cost.
r? ``@oli-obk``
r? ``@spastorino``
Implement jump threading MIR opt
This pass is an attempt to generalize `ConstGoto` and `SeparateConstSwitch` passes into a more complete jump threading pass.
This pass is rather heavy, as it performs a truncated backwards DFS on MIR starting from each `SwitchInt` terminator. This backwards DFS remains very limited, as it only walks through `Goto` terminators.
It is build to support constants and discriminants, and a propagating through a very limited set of operations.
The pass successfully manages to disentangle the `Some(x?)` use case and the DFA use case. It still needs a few tests before being ready.
coverage: Emit the filenames section before encoding per-function mappings
When embedding coverage information in LLVM IR (and ultimately in the resulting binary), there are two main things that each CGU needs to emit:
- A single `__llvm_covmap` record containing a coverage header, which mostly consists of a list of filenames used by the CGU's coverage mappings.
- Several `__llvm_covfun` records, one for each instrumented function, each of which contains the hash of the list of filenames in the header.
There is a kind of loose cyclic dependency between the two: we need the hash of the file table before we can emit the covfun records, but we need to traverse all of the instrumented functions in order to build the file table.
The existing code works by processing the individual functions first. It lazily adds filenames to the file table, and stores the mostly-complete function records in a temporary list. After this it hashes the file table, emits the header (containing the file table), and then uses the hash to emit all of the function records.
This PR reverses that order: first we traverse all of the functions (without trying to prepare their function records) to build a *complete* file table, and then emit it immediately. At this point we have the file table hash, so we can then proceed to build and emit all of the function records, without needing to store them in an intermediate list.
---
Along the way, this PR makes some necessary changes that are also worthwhile in their own right:
- We split `FunctionCoverage` into distinct collector/finished phases, which neatly avoids some borrow-checker hassles when extracting a function's final expression/mapping data.
- We avoid having to re-sort a function's mappings when preparing the list of filenames that it uses.
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
Uplift movability and mutability, the simple way
Just make type_ir a dependency of ast. This can be relaxed later if we want to make the dependency less heavy. Part of rust-lang/types-team#124.
r? `@lcnr` or `@jackh726`
Implement rustc part of RFC 3127 trim-paths
This PR implements (or at least tries to) [RFC 3127 trim-paths](https://github.com/rust-lang/rust/issues/111540), the rustc part. That is `-Zremap-path-scope` with all of it's components/scopes.
`@rustbot` label: +F-trim-paths
Normalize alloc-id in tests.
AllocIds are globally numbered in a rustc invocation. This makes them very sensitive to changes unrelated to what is being tested. This commit normalizes them by renumbering, in order of appearance in the output.
The renumbering allows to keep the identity, that a simple `allocN` wouldn't. This is useful when we have memory dumps.
cc `@saethlin`
r? `@oli-obk`
Remove cgu_reuse_tracker from Session
This removes a bit of global mutable state.
It will now miss post-lto cgu reuse when ThinLTO determines that a cgu doesn't get changed, but there weren't any tests for this anyway and a test for it would be fragile to the exact implementation of ThinLTO in LLVM.
Implement `-Clink-self-contained=-linker` opt out
This implements the `-Clink-self-contained` opt out necessary to switch to lld by changing rustc's defaults instead of cargo's.
Components that are enabled and disabled on the CLI are recorded, for the purpose of being merged with the ones which the target spec will declare (I'll open another PR for that tomorrow, for easier review).
For MCP510, we now check whether using the self-contained linker is disabled on the CLI. Right now it would only be sensible to with `-Zgcc-ld=lld` (and I'll add some checks that we don't both enable and disable a component on the CLI in a future PR), but the goal is to simplify adding the check of the target's enabled components here in the follow-up PRs.
r? `@petrochenkov`
