This adds an implementation of thread local storage for the
`wasm32-unknown-unknown` target when the `atomics` feature is
implemented. This, however, comes with a notable caveat of that it
requires a new feature of the standard library, `wasm-bindgen-threads`,
to be enabled.
Thread local storage for wasm (when `atomics` are enabled and there's
actually more than one thread) is powered by the assumption that an
external entity can fill in some information for us. It's not currently
clear who will fill in this information nor whose responsibility it
should be long-term. In the meantime there's a strategy being gamed out
in the `wasm-bindgen` project specifically, and the hope is that we can
continue to test and iterate on the standard library without committing
to a particular strategy yet.
As to the details of `wasm-bindgen`'s strategy, LLVM doesn't currently
have the ability to emit custom `global` values (thread locals in a
`WebAssembly.Module`) so we leverage the `wasm-bindgen` CLI tool to do
it for us. To that end we have a few intrinsics, assuming two global values:
* `__wbindgen_current_id` - gets the current thread id as a 32-bit
integer. It's `wasm-bindgen`'s responsibility to initialize this
per-thread and then inform libstd of the id. Currently `wasm-bindgen`
performs this initialization as part of the `start` function.
* `__wbindgen_tcb_{get,set}` - in addition to a thread id it's assumed
that there's a global available for simply storing a pointer's worth
of information (a thread control block, which currently only contains
thread local storage). This would ideally be a native `global`
injected by LLVM, but we don't have a great way to support that right
now.
To reiterate, this is all intended to be unstable and purely intended
for testing out Rust on the web with threads. The story is very likely
to change in the future and we want to make sure that we're able to do
that!
Fix range literals borrowing suggestions
Fixes#54505. The compiler issued incorrect range borrowing suggestions (missing `()` around borrows of range literals). This was not correct syntax (see the issue for an example).
With changes in this PR, this is fixed for all types of `Range` literals.
Thanks again to @varkor and @estebank for their invaluable help and guidance.
r? @varkor
Prepare miri engine for enforcing validity invariant during execution
In particular, make recursive checking of references optional, and add a `const_mode` parameter that says whether `usize` is allowed to contain a pointer. Also refactor validation a bit to be type-driven at the "leafs" (primitive types), and separately validate scalar layout to catch `NonNull` violations (which it did not properly validate before).
Fixes https://github.com/rust-lang/rust/issues/53826
Also fixes https://github.com/rust-lang/rust/issues/54751
r? @oli-obk
[NLL] Improve closure region bound errors
Previously, we would report free region errors that originate from closure with the span of the closure and a "closure body requires ..." message. This is now updated to use a reason and span from inside the closure.
Thanks to reviewers Tyler Mandry (for pointing out that this is
ridiculous and we need a helper function), Niko Matsakis (for pointing
out that the span-calculation code only has a couple free variables),
and Esteban Küber (for pointing out `get_generics`).
Add the library search box on the 404 page
It actually has a link to search already, but it would be better to
have the search "box" as like index.md to be consistent.
<style> can be shared with index.md, but these pages currently
use https://doc.rust-lang.org/rust.css directly.
Fixes#14572.
Fix dead code lint for functions using impl Trait
Fixes https://github.com/rust-lang/rust/issues/54754
This is a minimal fix that doesn't add any new queries or touches unnecessary code. Please nominate for beta backport if wanted.
rustc: Allow `#[no_mangle]` anywhere in a crate
This commit updates the compiler to allow the `#[no_mangle]` (and
`#[export_name]` attributes) to be located anywhere within a crate.
These attributes are unconditionally processed, causing the compiler to
always generate an exported symbol with the appropriate name.
After some discussion on #54135 it was found that not a great reason
this hasn't been allowed already, and it seems to match the behavior
that many expect! Previously the compiler would only export a
`#[no_mangle]` symbol if it were *publicly reachable*, meaning that it
itself is `pub` and it's otherwise publicly reachable from the root of
the crate. This new definition is that `#[no_mangle]` *is always
reachable*, no matter where it is in a crate or whether it has `pub` or
not.
This should make it much easier to declare an exported symbol with a
known and unique name, even when it's an internal implementation detail
of the crate itself. Note that these symbols will persist beyond LTO as
well, always making their way to the linker.
Along the way this commit removes the `private_no_mangle_functions` lint
(also for statics) as there's no longer any need to lint these
situations. Furthermore a good number of tests were updated now that
symbol visibility has been changed.
Closes#54135
NLL: temps in block tail expression diagnostic
This change adds a diagnostic that explains when temporaries in a block tail expression live longer than block local variables that they borrow, and attempts to suggest turning the tail expresion into a statement (either by adding a semicolon at the end, when its result value is clearly unused, or by introducing a `let`-binding for the result value and then returning that).
Fix#54556
This commit updates the compiler to allow the `#[no_mangle]` (and
`#[export_name]` attributes) to be located anywhere within a crate.
These attributes are unconditionally processed, causing the compiler to
always generate an exported symbol with the appropriate name.
After some discussion on #54135 it was found that not a great reason
this hasn't been allowed already, and it seems to match the behavior
that many expect! Previously the compiler would only export a
`#[no_mangle]` symbol if it were *publicly reachable*, meaning that it
itself is `pub` and it's otherwise publicly reachable from the root of
the crate. This new definition is that `#[no_mangle]` *is always
reachable*, no matter where it is in a crate or whether it has `pub` or
not.
This should make it much easier to declare an exported symbol with a
known and unique name, even when it's an internal implementation detail
of the crate itself. Note that these symbols will persist beyond LTO as
well, always making their way to the linker.
Along the way this commit removes the `private_no_mangle_functions` lint
(also for statics) as there's no longer any need to lint these
situations. Furthermore a good number of tests were updated now that
symbol visibility has been changed.
Closes#54135
