Rollup of 9 pull requests #82785
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Rollup of 9 pull requests #82785
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### Overview
This commit begins the implementation work for RFC 2945. For more
information, see the rendered RFC [1] and tracking issue [2].
A boolean `unwind` payload is added to the `C`, `System`, `Stdcall`,
and `Thiscall` variants, marking whether unwinding across FFI
boundaries is acceptable. The cases where each of these variants'
`unwind` member is true correspond with the `C-unwind`,
`system-unwind`, `stdcall-unwind`, and `thiscall-unwind` ABI strings
introduced in RFC 2945 [3].
### Feature Gate and Unstable Book
This commit adds a `c_unwind` feature gate for the new ABI strings.
Tests for this feature gate are included in `src/test/ui/c-unwind/`,
which ensure that this feature gate works correctly for each of the
new ABIs.
A new language features entry in the unstable book is added as well.
### Further Work To Be Done
This commit does not proceed to implement the new unwinding ABIs,
and is intentionally scoped specifically to *defining* the ABIs and
their feature flag.
### One Note on Test Churn
This will lead to some test churn, in re-blessing hash tests, as the
deleted comment in `src/librustc_target/spec/abi.rs` mentioned,
because we can no longer guarantee the ordering of the `Abi`
variants.
While this is a downside, this decision was made bearing in mind
that RFC 2945 states the following, in the "Other `unwind` Strings"
section [3]:
> More unwind variants of existing ABI strings may be introduced,
> with the same semantics, without an additional RFC.
Adding a new variant for each of these cases, rather than specifying
a payload for a given ABI, would quickly become untenable, and make
working with the `Abi` enum prone to mistakes.
This approach encodes the unwinding information *into* a given ABI,
to account for the future possibility of other `-unwind` ABI
strings.
### Ignore Directives
`ignore-*` directives are used in two of our `*-unwind` ABI test
cases.
Specifically, the `stdcall-unwind` and `thiscall-unwind` test cases
ignore architectures that do not support `stdcall` and
`thiscall`, respectively.
These directives are cribbed from
`src/test/ui/c-variadic/variadic-ffi-1.rs` for `stdcall`, and
`src/test/ui/extern/extern-thiscall.rs` for `thiscall`.
This would otherwise fail on some targets, see:
rust-lang-ci@fcf697f
### Footnotes
[1]: https://github.com/rust-lang/rfcs/blob/master/text/2945-c-unwind-abi.md
[2]: rust-lang#74990
[3]: https://github.com/rust-lang/rfcs/blob/master/text/2945-c-unwind-abi.md#other-unwind-abi-strings
### Changes
This commit implements unwind ABI's, specified in RFC 2945.
We adjust the `rustc_middle::ty::layout::fn_can_unwind` function,
used to compute whether or not a `FnAbi` object represents a
function that should be able to unwind when `panic=unwind` is in
use.
Changes are also made to
`rustc_mir_build::build::should_abort_on_panic` so that the
function ABI is used to determind whether it should abort, assuming
that the `panic=unwind` strategy is being used, and no explicit
unwind attribute was provided.
### Tests
Unit tests, checking that the behavior is correct for `C-unwind`,
`stdcall-unwind`, `system-unwind`, and `thiscall-unwind`, are
included. These alternative `unwind` ABI strings are specified in
RFC 2945, in the "_Other `unwind` ABI strings_" section.
Additionally, a test case is included to assert that the LLVM IR
generated for an external function defined with the `C-unwind` ABI
will be appropriately labeled with the `nounwind` LLVM attribute
when the `panic=abort` compilation flag is used.
### Ignore Directives
This commit uses `ignore-*` directives in two of our `*-unwind` ABI
test cases.
Specifically, the `stdcall-unwind` and `thiscall-unwind` test cases
ignore architectures that do not support `stdcall` and `thiscall`,
respectively.
These directives are cribbed from
`src/test/ui/c-variadic/variadic-ffi-1.rs` for `stdcall`, and
`src/test/ui/extern/extern-thiscall.rs` for `thiscall`.
### Integration Tests
This commit introduces some new fixtures to the `run-make-fulldeps`
test suite.
* c-unwind-abi-catch-panic: Exercise unwinding a panic. This
catches a panic across an FFI boundary and downcasts it into
an integer.
* c-unwind-abi-catch-lib-panic: This is similar to the previous
`*catch-panic` test, however in this case the Rust code that
panics resides in a separate crate.
### Add `rust_eh_personality` to `#[no_std]` alloc tests
This commit addresses some test failures that now occur in the
following two tests:
* no_std-alloc-error-handler-custom.rs
* no_std-alloc-error-handler-default.rs
Each test now defines a `rust_eh_personality` extern function, in
the same manner as shown in the "Writing an executable without
stdlib" section of the `lang_items` documentation here:
https://doc.rust-lang.org/unstable-book/language-features/lang-items.html#writing-an-executable-without-stdlib
Without this change, these tests would fail to compile due to a
linking error explaining that there was an "undefined reference
to `rust_eh_personality'."
### Updated hash
* update 32-bit hash in `impl1` test
### Panics
This commit uses `panic!` macro invocations that return a string,
rather than using an integer as a panic payload.
Doing so avoids the following warnings that were observed during
rollup for the `*-msvc-1` targets:
```
warning: panic message is not a string literal
--> panic.rs:10:16
|
10 | panic!(x); // That is too big!
| ^
|
= note: `#[warn(non_fmt_panic)]` on by default
= note: this is no longer accepted in Rust 2021
help: add a "{}" format string to Display the message
|
10 | panic!("{}", x); // That is too big!
| ^^^^^
help: or use std::panic::panic_any instead
|
10 | std::panic::panic_any(x); // That is too big!
| ^^^^^^^^^^^^^^^^^^^^^
warning: 1 warning emitted
```
See: https://github.com/rust-lang-ci/rust/runs/1992118428
As these errors imply, panicking without a format string will be
disallowed in Rust 2021, per rust-lang#78500.
### Add debug assertion to check `AbiDatas` ordering
This makes a small alteration to `Abi::index`, so that we include a
debug assertion to check that the index we are returning corresponds
with the same abi in our data array.
This will help prevent ordering bugs in the future, which can
manifest in rather strange errors.
### Using exhaustive ABI matches
This slightly modifies the changes from our previous commits,
favoring exhaustive matches in place of `_ => ...` fall-through
arms.
This should help with maintenance in the future, when additional
ABI's are added, or when existing ABI's are modified.
### List all `-unwind` ABI's in unstable book
This updates the `c-unwind` page in the unstable book to list _all_
of the other ABI strings that are introduced by this feature gate.
Now, all of the ABI's specified by RFC 2945 are shown.
Co-authored-by: Amanieu d'Antras <amanieu@gmail.com>
Co-authored-by: Niko Matsakis <niko@alum.mit.edu>
Due to a rebase, some edits were needed in the mod file.
- Remove most of the information about passes. Passes are deprecated. - Add `--document-private-items`; it was missing before. - Update `--output-format json`; it was very outdated. - Note that `--input-format` is deprecated. - Move deprecated options to the very end. - Move `passes.html` to the end of the table of contents. Ideally it would be removed altogether, but that causes mdbook not to generate the docs.
…inherits_doc_hidden
…atsakis Inherit `#[stable(..)]` annotations in enum variants and fields from its item Lint changes for rust-lang#65515. The stdlib will have to be updated once this lands in beta and that version is promoted in master.
…d-abi, r=Amanieu Implement RFC 2945: "C-unwind" ABI ## Implement RFC 2945: "C-unwind" ABI This branch implements [RFC 2945]. The tracking issue for this RFC is rust-lang#74990. The feature gate for the issue is `#![feature(c_unwind)]`. This RFC was created as part of the ffi-unwind project group tracked at rust-lang/lang-team#19. ### Changes Further details will be provided in commit messages, but a high-level overview of the changes follows: * A boolean `unwind` payload is added to the `C`, `System`, `Stdcall`, and `Thiscall` variants, marking whether unwinding across FFI boundaries is acceptable. The cases where each of these variants' `unwind` member is true correspond with the `C-unwind`, `system-unwind`, `stdcall-unwind`, and `thiscall-unwind` ABI strings introduced in RFC 2945 [3]. * This commit adds a `c_unwind` feature gate for the new ABI strings. Tests for this feature gate are included in `src/test/ui/c-unwind/`, which ensure that this feature gate works correctly for each of the new ABIs. A new language features entry in the unstable book is added as well. * We adjust the `rustc_middle::ty::layout::fn_can_unwind` function, used to compute whether or not a `FnAbi` object represents a function that should be able to unwind when `panic=unwind` is in use. * Changes are also made to `rustc_mir_build::build::should_abort_on_panic` so that the function ABI is used to determind whether it should abort, assuming that the `panic=unwind` strategy is being used, and no explicit unwind attribute was provided. [RFC 2945]: https://github.com/rust-lang/rfcs/blob/master/text/2945-c-unwind-abi.md
…c-hidden, r=jyn514 Don't warn for `missing_doc_examples` when item is #[doc(hidden)] r? ``@jyn514``
Implement NOOP_METHOD_CALL lint Implements the beginnings of rust-lang/lang-team#67 - a lint for detecting noop method calls (e.g, calling `<&T as Clone>::clone()` when `T: !Clone`). This PR does not fully realize the vision and has a few limitations that need to be addressed either before merging or in subsequent PRs: * [ ] No UFCS support * [ ] The warning message is pretty plain * [ ] Doesn't work for `ToOwned` The implementation uses [`Instance::resolve`](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_middle/ty/instance/struct.Instance.html#method.resolve) which is normally later in the compiler. It seems that there are some invariants that this function relies on that we try our best to respect. For instance, it expects substitutions to have happened, which haven't yet performed, but we check first for `needs_subst` to ensure we're dealing with a monomorphic type. Thank you to `@davidtwco,` `@Aaron1011,` and `@wesleywiser` for helping me at various points through out this PR ❤️.
resolve: Reduce scope of `pub_use_of_private_extern_crate` deprecation lint This lint was deny-by-default since July 2017, crater showed 7 uses on crates.io back then (rust-lang#42894 (comment)). Unfortunately, the construction `pub use foo as bar` where `foo` is `extern crate foo;` was used by an older version `bitflags`, so turning it into an error causes too many regressions. So, this PR reduces the scope of the lint instead of turning it into a hard error, and only turns some more rarely used components of it into errors.
…ramertj Improved IO Bytes Size Hint After trying to implement better `size_hint()` return values for `File` in [this PR](rust-lang#81044) and changing to implementing it for `BufReader` in [this PR](rust-lang#81052), I have arrived at this implementation that provides tighter bounds for the `Bytes` iterator of various readers including `BufReader`, `Empty`, and `Chain`. Unfortunately, for `BufReader`, the size_hint only improves after calling `fill_buffer` due to it using the contents of the buffer for the hint. Nevertheless, the the tighter bounds should result in better pre-allocation of space to handle the contents of the `Bytes` iterator. Closes rust-lang#81052
… r=davidtwco Add suggestion `.collect()` for iterators in iterators Closes rust-lang#81584 ``` error[E0515]: cannot return value referencing function parameter `y` --> main3.rs:4:38 | 4 | ... .map(|y| y.iter().map(|x| x + 1)) | -^^^^^^^^^^^^^^^^^^^^^^ | | | returns a value referencing data owned by the current function | `y` is borrowed here | help: Maybe use `.collect()` to allocate the iterator ``` Added the suggestion: `help: Maybe use `.collect()` to allocate the iterator`
… r=GuillaumeGomez Shorten html::render The `mod.rs` for librustdoc's `html::render` was over 3,000 lines. This PR reduces it to around 2,300 by 1. Moving `Context` and associated `impl`s to a separate file 2. Moving the `print_item` function and its helpers to a separate file 3. Moving `write_shared` and `write_minify` to their own file Related to issue rust-lang#60302. Edit 1: `SharedContext` and related `impl`s is only 72 lines and so will not be moved.
Update rustdoc documentation - Remove most of the information about passes. Passes are deprecated. - Add `--document-private-items`; it was missing before. - Update `--output-format json`; it was very outdated. - Note that `--input-format` is deprecated. - Move deprecated options to the very end. Closes rust-lang#82675. r? ``@Manishearth``
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Successful merges:
#[stable(..)]annotations in enum variants and fields from its item #71481 (Inherit#[stable(..)]annotations in enum variants and fields from its item)missing_doc_exampleswhen item is #[doc(hidden)] #76716 (Don't warn formissing_doc_exampleswhen item is #[doc(hidden)])pub_use_of_private_extern_cratedeprecation lint #80763 (resolve: Reduce scope ofpub_use_of_private_extern_cratedeprecation lint).collect()for iterators in iterators #81939 (Add suggestion.collect()for iterators in iterators)Failed merges:
r? @ghost
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