This commit updates the `backtrace` crate from 0.3.34 to 0.3.35. The
[included set of changes][changes] for this update mostly includes some
gimli-related improvements (not relevant for the standard library) but
critically includes a fix for rust-lang/backtrace-rs#230. The standard
library will not aqcuire a session-local lock whenever a backtrace is
generated on Windows to allow external synchronization with the
`backtrace` crate itself, allowing `backtrace` to be safely used while
other threads may be panicking.
[changes]: https://github.com/rust-lang/backtrace-rs/compare/0.3.34...0.3.35
Don't special case the `Self` parameter by name
This results in a couple of small diagnostic regressions. They could be avoided by keeping the special case just for diagnostics, but that seems worse.
closes#50125
cc #60869
Change the placement of two functions.
Right now, the order is as follows:
`pop_front()`
`push_front()`
`push_back()`
`pop_back()`
`swap_remove_back()`
`swap_remove_front()`
I believe it would be more natural, and easier to follow, if we place `pop_back()` right after the `pop_front()`, and `swap_remove_back()` after the `swap_remove_front()` like this:
`pop_front()`
`pop_back()`
`push_front()`
`push_back()`
`swap_remove_front()`
`swap_remove_back()`
The rest of the documentation (at least in this module) adheres to the same logic, where the 'front' function always precedes its 'back' equivalent.
Do not generate allocations for zero sized allocations
Alternative to https://github.com/rust-lang/rust/issues/62487
r? @eddyb
There are other places where we could do this, too, but that would cause `static FOO: () = ();` to not have a unique address
Serialize additional data for procedural macros
Split off from #62855
This PR serializes the declaration `Span` and attributes for all
procedural macros. This allows Rustdoc to properly render doc comments
and source links when performing inlinig procedural macros across crates
Initial implementation of or-patterns
An incomplete implementation of or-patterns (e.g. `Some(0 | 1)` as a pattern). This patch set aims to implement initial parsing of `or-patterns`.
Related to: #54883
CC @alexreg @varkor
r? @Centril
resolve: Properly integrate derives and `macro_rules` scopes
So,
```rust
#[derive(A, B)]
struct S;
m!();
```
turns into something like
```rust
struct S;
A_placeholder!( struct S; );
B_placeholder!( struct S; );
m!();
```
during expansion.
And for `m!()` its "`macro_rules` scope" (aka "legacy scope") should point to the `B_placeholder` call rather than to the derive container `#[derive(A, B)]`.
`fn build_reduced_graph` now makes sure the legacy scope points to the right thing.
(It's still a mystery for me why this worked before https://github.com/rust-lang/rust/pull/63535.)
Unfortunately, placeholders from derives are currently treated separately from placeholders from other macros and need to be passed as `extra_placeholders` rather than a part of the AST fragment.
That's fixable, but I wanted to keep this PR more minimal to close the regression faster.
Fixes https://github.com/rust-lang/rust/issues/63651
r? @matthewjasper
Add APIs for uninitialized Box, Rc, and Arc. (Plus get_mut_unchecked)
Assigning `MaybeUninit::<Foo>::uninit()` to a local variable is usually free, even when `size_of::<Foo>()` is large. However, passing it for example to `Arc::new` [causes at least one copy](https://youtu.be/F1AquroPfcI?t=4116) (from the stack to the newly allocated heap memory) even though there is no meaningful data. It is theoretically possible that a Sufficiently Advanced Compiler could optimize this copy away, but this is [reportedly unlikely to happen soon in LLVM](https://youtu.be/F1AquroPfcI?t=5431).
This PR proposes two sets of features:
* Constructors for containers (`Box`, `Rc`, `Arc`) of `MaybeUninit<T>` or `[MaybeUninit<T>]` that do not initialized the data, and unsafe conversions to the known-initialized types (without `MaybeUninit`). The constructors are guaranteed not to make unnecessary copies.
* On `Rc` and `Arc`, an unsafe `get_mut_unchecked` method that provides `&mut T` access without checking the reference count. `Arc::get_mut` involves multiple atomic operations whose cost can be non-trivial. `Rc::get_mut` is less costly, but we add `Rc::get_mut_unchecked` anyway for symmetry with `Arc`.
These can be useful independently, but they will presumably be typical when the new constructors of `Rc` and `Arc` are used.
An alternative with a safe API would be to introduce `UniqueRc` and `UniqueArc` types that have the same memory layout as `Rc` and `Arc` (and so zero-cost conversion to them) but are guaranteed to have only one reference. But introducing entire new types feels “heavier” than new constructors on existing types, and initialization of `MaybeUninit<T>` typically requires unsafe code anyway.
Summary of new APIs (all unstable in this PR):
```rust
impl<T> Box<T> { pub fn new_uninit() -> Box<MaybeUninit<T>> {…} }
impl<T> Box<MaybeUninit<T>> { pub unsafe fn assume_init(self) -> Box<T> {…} }
impl<T> Box<[T]> { pub fn new_uninit_slice(len: usize) -> Box<[MaybeUninit<T>]> {…} }
impl<T> Box<[MaybeUninit<T>]> { pub unsafe fn assume_init(self) -> Box<[T]> {…} }
impl<T> Rc<T> { pub fn new_uninit() -> Rc<MaybeUninit<T>> {…} }
impl<T> Rc<MaybeUninit<T>> { pub unsafe fn assume_init(self) -> Rc<T> {…} }
impl<T> Rc<[T]> { pub fn new_uninit_slice(len: usize) -> Rc<[MaybeUninit<T>]> {…} }
impl<T> Rc<[MaybeUninit<T>]> { pub unsafe fn assume_init(self) -> Rc<[T]> {…} }
impl<T> Arc<T> { pub fn new_uninit() -> Arc<MaybeUninit<T>> {…} }
impl<T> Arc<MaybeUninit<T>> { pub unsafe fn assume_init(self) -> Arc<T> {…} }
impl<T> Arc<[T]> { pub fn new_uninit_slice(len: usize) -> Arc<[MaybeUninit<T>]> {…} }
impl<T> Arc<[MaybeUninit<T>]> { pub unsafe fn assume_init(self) -> Arc<[T]> {…} }
impl<T: ?Sized> Rc<T> { pub unsafe fn get_mut_unchecked(this: &mut Self) -> &mut T {…} }
impl<T: ?Sized> Arc<T> { pub unsafe fn get_mut_unchecked(this: &mut Self) -> &mut T {…} }
```
Refactor Miri ops (unary, binary) to have more types
This is the part of https://github.com/rust-lang/rust/pull/63448 that is just a refactoring. It helps that PR by making it easier to perform machine arithmetic.
r? @oli-obk @eddyb
Split off from #62855
This PR deerializes the declaration `Span` and attributes for all
procedural macros from their underlying function definitions.
This allows Rustdoc to properly render doc comments
and source links when inlining procedural macros across crates
Opaque builtin derive macros
* Buiilt-in derives are now opaque macros
* This required limiting the visibility of some previously unexposed functions in `core`.
* This also required the change to `Ident` serialization.
* All gensyms are replaced with hygienic identifiers
* Use hygiene to avoid most other name-resolution issues with buiilt-in derives.
* As far as I know the only remaining case that breaks is an ADT that has the same name as one of its parameters. Fixing this completely seemed to be more effort than it's worth.
* Remove gensym in `Ident::decode`, which lead to linker errors due to `inline` being gensymmed.
* `Ident`now panics if incremental compilation tries to serialize it (it currently doesn't).
* `Ident` no longer uses `gensym` to emulate cross-crate hygiene. It only applied to reexports.
* `SyntaxContext` is no longer serializable.
* The long-term fix for this is to properly implement cross-crate hygiene, but this seemed to be acceptable for now.
* Move type/const parameter shadowing checks to `resolve`
* This was previously split between resolve and type checking. The type checking pass compared `InternedString`s, not Identifiers.
* Removed the `SyntaxContext` from `{ast, hir}::{InlineAsm, GlobalAsm}`
cc #60869
r? @petrochenkov
Modify librustc_llvm to pass -DNDEBUG while compiling.
Currently, librustc_llvm builds are not reproducible because the LLVM files it compiles use the debug version of llvm_unreachable, which uses __FILE__. To fix this, we propagate NDEBUG from bootstrap if applicable and use it when compiling librustc_llvm.
r? @alexcrichton
rustc_codegen_utils: account for 1-indexed anonymous lifetimes in v0 mangling.
I don't really understand why `anonymize_late_bound_regions` starts with `BrAnon(1)` instead of `BrAnon(0)`, but it does (maybe @nikomatsakis knows?): c43d03a19f/src/librustc/ty/fold.rs (L696-L712)
Thankfully, the mangling format and demangler implementations are fine, and I just needed to offset the anonymized lifetime indices by `1` to get the correct mangling.
cc @alexcrichton @michaelwoerister
Hash the remapped sysroot instead of the original.
One of the reasons that rustc builds are not reproducible is because the --sysroot path is dependent on the current directory. We can fix this by hashing the remapped sysroot instead of the original when applicable.
Note that with this patch, the hash will stay the same if both the sysroot and the remapped path change. However, given that if the contents of the sysroot change the hash will also stay the same, this might be acceptable. I would appreciate feedback on the best way to do this.
This helps #34902, although it does not fix it by itself.
Override Cycle::try_fold
It's not very pretty, but I believe this is the simplest way to correctly implement `Cycle::try_fold`. The following may seem correct:
```rust
loop {
acc = self.iter.try_fold(acc, &mut f)?;
self.iter = self.orig.clone();
}
```
...but this loops infinitely in case `self.orig` is empty, as opposed to returning `acc`. So we first have to fully iterate `self.orig` to check whether it is empty or not, and before _that_, we have to iterate the remaining elements of `self.iter`.
This should always call `self.orig.clone()` the same amount of times as repeated `next()` calls would.
r? @scottmcm
