[Gardening] Update outdated comments: ByVal -> Scalar
ByVal enum cases in mir::interpret::value were renamed to Scalar a while ago but comments still refer to the old names.
Strenghten synchronization in `Arc::is_unique`
Previously, `is_unique` would not synchronize at all with a `drop` that returned
early because it was not the last reference, leading to a data race.
Fixes#51780
Unfortunately I have no idea how to add a test for this.
Cc @jhjourdan
Any docs preposition change
This changes the docs referring to where a user should be wary of depending on "Any" trait impls from warning about relying on them "outside" of their code to warning about relying on them "inside" of their code.
[cross-lang-lto] Allow the linker to choose the LTO-plugin (which is useful when using LLD)
This PR allows for not specifying an LTO-linker plugin but still let `rustc` invoke the linker with the correct plugin arguments. This is useful when using LLD which does not need the `-plugin` argument. Since LLD is the best linker for this scenario anyway, this change should improve ergonomics quite a bit.
r? @alexcrichton
closes#45085
this commit adds an `atomic_cas` target option and an unstable `#[cfg(target_has_atomic_cas)]`
attribute to enable a subset of the `Atomic*` API on architectures that don't support atomic CAS
natively, like MSP430 and ARMv6-M.
We represent `bool` as `i1` in a `ScalarPair`, unlike other aggregates,
to optimize IR for checked operators and the like. With this patch, we
still do so when the pair is an immediate value, but we use the `i8`
memory type when the value is loaded or stored as an LLVM aggregate.
So `(bool, bool)` looks like an `{ i1, i1 }` immediate, but `{ i8, i8 }`
in memory. When a pair is a direct function argument, `PassMode::Pair`,
it is still passed using the immediate `i1` type, but as a return value
it will use the `i8` memory type. Also, `bool`-like` enum tags will now
use scalar pairs when possible, where they were previously excluded due
to optimization issues.
The docs were not specifying how to compute the alignment of the struct, so I had to spend some time trying to figure out how that works. Found the answer [on this page](http://camlorn.net/posts/April%202017/rust-struct-field-reordering.html):
> The total size of this struct is 5, but the most-aligned field is b with alignment 2, so we round up to 6 and give the struct an alignment of 2 bytes.
Fix various issues with control-flow statements inside anonymous constants
Fixes#51761.
Fixes#51963 (and the host of other reported issues there).
(Might be easiest to review per commit, as they should be standalone.)
r? @estebank
rename rustc's lld to rust-lld
to not shadow the system installed LLD when linking with LLD.
Before:
- `-C linker=lld -Z linker-flavor=ld.lld` uses rustc's LLD
- It's not possible to use a system installed LLD that's named `lld`
With this commit:
- `-C linker=rust-lld -Z linker-flavor=ld.lld` uses rustc's LLD
- `-C linker=lld -Z linker-flavor=ld.lld` uses the system installed LLD
we don't offer guarantees about the availability of LLD in the rustc sysroot so we can rename the tool as long as we don't break the wasm32-unknown-unknown target which depends on it.
r? @alexcrichton we discussed this before
in which we plug the crack where `?`-desugaring leaked into errors
Most of the time, it's not a problem that the types of the arm bodies in
a desugared-from-`?` match are different (that is, specifically: in `x?`
where x is a `Result<A, B>`, the `Ok` arm body is an `A`, whereas the
`Err` arm diverges to return a `Result<A, B>`), because they're being
assigned to different places. But in tail position, the types do need to
match, and our error message was explicitly referring to "match arms",
which is confusing when there's no `match` in the sweetly sugared
source.
It is not without some misgivings that we pollute the clarity-of-purpose
of `note_error_origin` with the suggestion to wrap with `Ok` (the other
branches are pointing out the odd-arm-out in the HIR that is the origin
of the error; the new branch that issues the `Ok` suggestion is serving
a different purpose), but it's the natural place to do it given that
we're already matching on `ObligationCauseCode::MatchExpressionArm {
arm_span, source }` there.
Resolves#51632.
