rustc_query_system: simplify QueryCache::iter
Minor cleanup to reduce a small amount of complexity and code bloat.
Reduces the number of mono items in rustc_query_impl by 15%.
2229: Handle capturing a reference into a repr packed struct
RFC 1240 states that it is unsafe to capture references into a
packed-struct. This PR ensures that when a closure captures a precise
path, we aren't violating this safety constraint.
To acheive so we restrict the capture precision to the struct itself.
An interesting edge case where we decided to restrict precision:
```rust
struct Foo(String);
let foo: Foo;
let c = || {
println!("{}", foo.0);
let x = foo.0;
}
```
Given how closures get desugared today, foo.0 will be moved into the
closure, making the `println!`, safe. However this can be very subtle
and also will be unsafe if the closure gets inline.
Closes: https://github.com/rust-lang/project-rfc-2229/issues/33
r? `@nikomatsakis`
Allow calling *const methods on *mut values
This allows `*const` methods to be called on `*mut` values.
TODOs:
- [x] ~~Remove debug logs~~ Done.
- [x] ~~I haven't tested, but I think this currently won't work when the `self` value has type like `&&&&& *mut X` because I don't do any autoderefs when probing. To fix this the new code in `rustc_typeck::check::method::probe` needs to reuse `pick_method` somehow as I think that's the function that autoderefs.~~ This works, because autoderefs are done before calling `pick_core`, in `method_autoderef_steps`, called by `probe_op`.
- [x] ~~I should probably move the new `Pick` to `pick_autorefd_method`. If not, I should move it to its own function.~~ Done.
- [ ] ~~Test this with a `Pick` with `to_ptr = true` and `unsize = true`.~~ I think this case cannot happen, because we don't have any array methods with `*mut [X]` receiver. I should confirm that this is true and document this. I've placed two assertions about this.
- [x] ~~Maybe give `(Mutability, bool)` a name and fields~~ I now have a `to_const_ptr` field in `Pick`.
- [x] ~~Changes in `adjust_self_ty` is quite hacky. The problem is we can't deref a pointer, and even if we don't have an adjustment to get the address of a value, so to go from `*mut` to `*const` we need a special case.~~ There's still a special case for `to_const_ptr`, but I'm not sure if we can avoid this.
- [ ] Figure out how `reached_raw_pointer` stuff is used. I suspect only for error messages.
Fixes#80258
expand: Do not allocate `Lrc` for `allow_internal_unstable` list unless necessary
This allocation is done for any macro defined in the current crate, or used from a different crate.
EDIT: This also removes an `Lrc` increment from each *use* of such macro, which may be more significant.
Noticed when reviewing https://github.com/rust-lang/rust/pull/82367.
This probably doesn't matter, but let's do a perf run.
Adjust some `#[cfg]`s to take non-Unix non-Windows operating systems into account
This makes compilation to such targets (e.g. `wasm32-wasi`) easier.
cc rust-lang/miri#722bb6d1d0a09 (r48100619)
Eagerly construct bodies of THIR
With this PR:
- the THIR is no longer constructed lazily, but is entirely built before being passed to the MIR Builder
- the THIR is now allocated in arenas instead of `Box`es
However, this PR doesn't make any changes to the way patterns are constructed: they are still boxed, and exhaustiveness checking is unchanged.
Implements MCP rust-lang/compiler-team#409.
Closesrust-lang/project-thir-unsafeck#1.
r? `@ghost` cc `@nikomatsakis` `@oli-obk`
Shorten `rustc_middle::ty::mod`
Related to #60302.
This PR moves all `Adt*`, `Assoc*`, `Generic*`, and `UpVar*` types to separate files.
This, alongside some `use` reordering, puts `mod.rs` at ~2,200 lines, thus removing the `// ignore-tidy-filelength`.
The particular groups were chosen as they had 4 or more "substantive" members.
Rollup of 9 pull requests
Successful merges:
- #81309 (always eagerly eval consts in Relate)
- #82217 (Edition-specific preludes)
- #82807 (rustdoc: Remove redundant enableSearchInput function)
- #82924 (WASI: Switch to crt1-command.o to enable support for new-style commands)
- #82949 (Do not attempt to unlock envlock in child process after a fork.)
- #82955 (fix: wrong word)
- #82962 (Treat header as first paragraph for shortened markdown descriptions)
- #82976 (fix error message for copy(_nonoverlapping) overflow)
- #82977 (Rename `Option::get_or_default` to `get_or_insert_default`)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
WASI: Switch to crt1-command.o to enable support for new-style commands
This switches Rust's WASI target to use crt1-command.o instead of
crt1.o, which enables support for new-style commands. By default,
new-style commands work the same way as old-style commands, so nothing
immediately changes here, but this will be needed by later changes to
enable support for typed arguments.
See here for more information on new-style commands:
- https://github.com/WebAssembly/wasi-libc/pull/203
- https://reviews.llvm.org/D81689
r? ```@alexcrichton```
Edition-specific preludes
This changes `{std,core}::prelude` to export edition-specific preludes under `rust_2015`, `rust_2018` and `rust_2021`. (As suggested in https://github.com/rust-lang/rust/issues/51418#issuecomment-395630382.) For now they all just re-export `v1::*`, but this allows us to add things to the 2021edition prelude soon.
This also changes the compiler to make the automatically injected prelude import dependent on the selected edition.
cc `@rust-lang/libs` `@djc`
Implement RFC 2945: "C-unwind" ABI
## Implement RFC 2945: "C-unwind" ABI
This branch implements [RFC 2945]. The tracking issue for this RFC is #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
Remove the -Zinsert-sideeffect
This removes all of the code we had in place to work-around LLVM's
handling of forward progress. From this removal excluded is a workaround
where we'd insert a `sideeffect` into clearly infinite loops such as
`loop {}`. This code remains conditionally effective when the LLVM
version is earlier than 12.0, which fixed the forward progress related
miscompilations at their root.
This removes all of the code we had in place to work-around LLVM's
handling of forward progress. From this removal excluded is a workaround
where we'd insert a `sideeffect` into clearly infinite loops such as
`loop {}`. This code remains conditionally effective when the LLVM
version is earlier than 12.0, which fixed the forward progress related
miscompilations at their root.
Store HIR attributes in a side table
Same idea as #72015 but for attributes.
The objective is to reduce incr-comp invalidations due to modified attributes.
Notably, those due to modified doc comments.
Implementation:
- collect attributes during AST->HIR lowering, in `LocalDefId -> ItemLocalId -> &[Attributes]` nested tables;
- access the attributes through a `hir_owner_attrs` query;
- local refactorings to use this access;
- remove `attrs` from HIR data structures one-by-one.
Change in behaviour:
- the HIR visitor traverses all attributes at once instead of parent-by-parent;
- attribute arrays are sometimes duplicated: for statements and variant constructors;
- as a consequence, attributes are marked as used after unused-attribute lint emission to avoid duplicate lints.
~~Current bug: the lint level is not correctly applied in `std::backtrace_rs`, triggering an unused attribute warning on `#![no_std]`. I welcome suggestions.~~
