Add std Xtensa targets support
Adds std Xtensa targets. This enables using Rust on ESP32, ESP32-S2 and ESP32-S3 chips.
Tier 3 policy:
> A tier 3 target must have a designated developer or developers (the "target maintainers") on
record to be CCed when issues arise regarding the target. (The mechanism to track and CC such
developers may evolve over time.)
`@MabezDev,` `@ivmarkov` and I (`@SergioGasquez)` will maintain the targets.
> Targets must use naming consistent with any existing targets; for instance, a target for the same
CPU or OS as an existing Rust target should use the same name for that CPU or OS. Targets should
normally use the same names and naming conventions as used elsewhere in the broader ecosystem beyond
Rust (such as in other toolchains), unless they have a very good reason to diverge. Changing the
name of a target can be highly disruptive, especially once the target reaches a higher tier, so
getting the name right is important even for a tier 3 target.
The target triple is consistent with other targets.
> Target names should not introduce undue confusion or ambiguity unless absolutely necessary to
maintain ecosystem compatibility. For example, if the name of the target makes people extremely
likely to form incorrect beliefs about what it targets, the name should be changed or augmented to
disambiguate it.
> If possible, use only letters, numbers, dashes and underscores for the name. Periods (.) are known
to cause issues in Cargo.
We follow the same naming convention as other targets.
> Tier 3 targets may have unusual requirements to build or use, but must not create legal issues or
impose onerous legal terms for the Rust project or for Rust developers or users.
The target does not introduce any legal issues.
> The target must not introduce license incompatibilities.
There are no license incompatibilities
> Anything added to the Rust repository must be under the standard Rust license (MIT OR Apache-2.0).
Everything added is under that licenses
> The target must not cause the Rust tools or libraries built for any other host (even when
supporting cross-compilation to the target) to depend on any new dependency less permissive than the
Rust licensing policy. This applies whether the dependency is a Rust crate that would require adding
new license exceptions (as specified by the tidy tool in the rust-lang/rust repository), or whether
the dependency is a native library or binary. In other words, the introduction of the target must
not cause a user installing or running a version of Rust or the Rust tools to be subject to any new
license requirements.
Requirements are not changed for any other target.
> Compiling, linking, and emitting functional binaries, libraries, or other code for the target
(whether hosted on the target itself or cross-compiling from another target) must not depend on
proprietary (non-FOSS) libraries. Host tools built for the target itself may depend on the ordinary
runtime libraries supplied by the platform and commonly used by other applications built for the
target, but those libraries must not be required for code generation for the target;
cross-compilation to the target must not require such libraries at all. For instance, rustc built
for the target may depend on a common proprietary C runtime library or console output library, but
must not depend on a proprietary code generation library or code optimization library. Rust's
license permits such combinations, but the Rust project has no interest in maintaining such
combinations within the scope of Rust itself, even at tier 3.
The linker used by the targets is the GCC linker from the GCC toolchain cross-compiled for Xtensa.
GNU GPL.
> "onerous" here is an intentionally subjective term. At a minimum, "onerous" legal/licensing terms
include but are not limited to: non-disclosure requirements, non-compete requirements, contributor
license agreements (CLAs) or equivalent, "non-commercial"/"research-only"/etc terms, requirements
conditional on the employer or employment of any particular Rust developers, revocable terms, any
requirements that create liability for the Rust project or its developers or users, or any
requirements that adversely affect the livelihood or prospects of the Rust project or its developers
or users.
No such terms exist for this target
> Neither this policy nor any decisions made regarding targets shall create any binding agreement or
estoppel by any party. If any member of an approving Rust team serves as one of the maintainers of a
target, or has any legal or employment requirement (explicit or implicit) that might affect their
decisions regarding a target, they must recuse themselves from any approval decisions regarding the
target's tier status, though they may otherwise participate in discussions.
> This requirement does not prevent part or all of this policy from being cited in an explicit
contract or work agreement (e.g. to implement or maintain support for a target). This requirement
exists to ensure that a developer or team responsible for reviewing and approving a target does not
face any legal threats or obligations that would prevent them from freely exercising their judgment
in such approval, even if such judgment involves subjective matters or goes beyond the letter of
these requirements.
Understood
> Tier 3 targets should attempt to implement as much of the standard libraries as possible and
appropriate (core for most targets, alloc for targets that can support dynamic memory allocation,
std for targets with an operating system or equivalent layer of system-provided functionality), but
may leave some code unimplemented (either unavailable or stubbed out as appropriate), whether
because the target makes it impossible to implement or challenging to implement. The authors of pull
requests are not obligated to avoid calling any portions of the standard library on the basis of a
tier 3 target not implementing those portions.
The targets implement libStd almost in its entirety, except for the missing support for process, as
this is a bare metal platform. The process `sys\unix` module is currently stubbed to return "not
implemented" errors.
> The target must provide documentation for the Rust community explaining how to build for the
target, using cross-compilation if possible. If the target supports running binaries, or running
tests (even if they do not pass), the documentation must explain how to run such binaries or tests
for the target, using emulation if possible or dedicated hardware if necessary.
Here is how to build for the target https://docs.esp-rs.org/book/installation/riscv-and-xtensa.html
and it also covers how to run binaries on the target.
> Tier 3 targets must not impose burden on the authors of pull requests, or other developers in the
community, to maintain the target. In particular, do not post comments (automated or manual) on a PR
that derail or suggest a block on the PR based on a tier 3 target. Do not send automated messages or
notifications (via any medium, including via `@)` to a PR author or others involved with a PR
regarding a tier 3 target, unless they have opted into such messages.
> Backlinks such as those generated by the issue/PR tracker when linking to an issue or PR are not
considered a violation of this policy, within reason. However, such messages (even on a separate
repository) must not generate notifications to anyone involved with a PR who has not requested such
notifications.
Understood
> Patches adding or updating tier 3 targets must not break any existing tier 2 or tier 1 target, and
must not knowingly break another tier 3 target without approval of either the compiler team or the
maintainers of the other tier 3 target.
> In particular, this may come up when working on closely related targets, such as variations of the
same architecture with different features. Avoid introducing unconditional uses of features that
another variation of the target may not have; use conditional compilation or runtime detection, as
appropriate, to let each target run code supported by that target.
No other targets should be affected
> Tier 3 targets must be able to produce assembly using at least one of rustc's supported backends
from any host target.
It can produce assembly, but it requires a custom LLVM with Xtensa support
(https://github.com/espressif/llvm-project/). The patches are trying to be upstreamed
(https://github.com/espressif/llvm-project/issues/4)
Trying to address an incremental compilation issues
This pull request contains two independent changes, one makes it so when `try_force_from_dep_node` fails to recover a query - it marks the node as "red" instead of "green" and the second one makes Debug impl for `DepNode` less panicky if it encounters something from the previous compilation that doesn't map to anything in the current one.
I'm not 100% confident that this is the correct approach, but so far I managed to find a bunch of comments suggesting that some things are allowed to fail in a certain way and changes I made are allowing for those things to fail this way and it fixes all the small reproducers I managed to find.
Compilation panic this pull request avoids is caused by an automatically generated code on an associated type and it is not happening if something else marks it as outdated first (or close like that, but scenario is quite obscure).
Fixes https://github.com/rust-lang/rust/issues/107226
Fixes https://github.com/rust-lang/rust/issues/125367
Rollup of 5 pull requests
Successful merges:
- #126620 (Actually taint InferCtxt when a fulfillment error is emitted)
- #126649 (Fix `feature = "nightly"` in the new trait solver)
- #126652 (Clarify that anonymous consts still do introduce a new scope)
- #126703 (reword the hint::blackbox non-guarantees)
- #126708 (Minimize `can_begin_literal_maybe_minus` usage)
r? `@ghost`
`@rustbot` modify labels: rollup
Clarify that anonymous consts still do introduce a new scope
See https://github.com/rust-lang/rust/issues/120363#issuecomment-2177064702
This error message is misleading: it's trying to say that `const _ : () = ...` is a workaround for the lint, but by saying that anonymous constants are treated as being in the parent scope, it makes them appear useless for scope-hiding.
They *are* useful for scope-hiding, they are simply treated as part of the parent scope when it comes to this lint.
Actually taint InferCtxt when a fulfillment error is emitted
And avoid checking the global error counter
fixes#122044fixes#123255fixes#123276fixes#125799
Implement `array::repeat`
See rust-lang/libs-team#310.
I've decided to make the function use the input value as last element instead of cloning it to every position and dropping it, and to make this part of the API so that callers are not surprised by this behaviour.
TODO: open a tracking issue. I'll wait for the ACP to be accepted, first.
`@rustbot` label +T-libs-api +T-libs
r? libs
Apparently MIR borrowck cares about at least one of these for checking variance.
In runtime MIR, though, there's no need for them as `PtrToPtr` does the same thing.
(Banning them simplifies passes like GVN that no longer need to handle multiple cast possibilities.)
Fix duplicated attributes on nonterminal expressions
This PR fixes a long-standing bug (#86055) whereby expression attributes can be duplicated when expanded through declarative macros.
First, consider how items are parsed in declarative macros:
```
Items:
- parse_nonterminal
- parse_item(ForceCollect::Yes)
- parse_item_
- attrs = parse_outer_attributes
- parse_item_common(attrs)
- maybe_whole!
- collect_tokens_trailing_token
```
The important thing is that the parsing of outer attributes is outside token collection, so the item's tokens don't include the attributes. This is how it's supposed to be.
Now consider how expression are parsed in declarative macros:
```
Exprs:
- parse_nonterminal
- parse_expr_force_collect
- collect_tokens_no_attrs
- collect_tokens_trailing_token
- parse_expr
- parse_expr_res(None)
- parse_expr_assoc_with
- parse_expr_prefix
- parse_or_use_outer_attributes
- parse_expr_dot_or_call
```
The important thing is that the parsing of outer attributes is inside token collection, so the the expr's tokens do include the attributes, i.e. in `AttributesData::tokens`.
This PR fixes the bug by rearranging expression parsing to that outer attribute parsing happens outside of token collection. This requires a number of small refactorings because expression parsing is somewhat complicated. While doing so the PR makes the code a bit cleaner and simpler, by eliminating `parse_or_use_outer_attributes` and `Option<AttrWrapper>` arguments (in favour of the simpler `parse_outer_attributes` and `AttrWrapper` arguments), and simplifying `LhsExpr`.
r? `@petrochenkov`
The way it is implemented currently try_force_from_dep_node returns true
as long as there's a function to force the query. It wasn't this way
from the beginning, earlier version was producing forcing result and it
was changed in https://github.com/rust-lang/rust/pull/89978, I couldn't
find any comments addressing this change.
One way it can fail is by failing to recover the query in
DepNodeParams::recover - when we are trying to query something that no
longer exists in the current environment
Rollup of 6 pull requests
Successful merges:
- #125447 (Allow constraining opaque types during subtyping in the trait system)
- #125766 (MCDC Coverage: instrument last boolean RHS operands from condition coverage)
- #125880 (Remove `src/tools/rust-demangler`)
- #126154 (StorageLive: refresh storage (instead of UB) when local is already live)
- #126572 (override user defined channel when using precompiled rustc)
- #126662 (Unconditionally warn on usage of `wasm32-wasi`)
r? `@ghost`
`@rustbot` modify labels: rollup
MCDC Coverage: instrument last boolean RHS operands from condition coverage
Fresh PR from #124652
--
This PR ensures that the top-level boolean expressions that are not part of the control flow are correctly instrumented thanks to condition coverage.
See discussion on https://github.com/rust-lang/rust/issues/124120.
Depends on `@Zalathar` 's condition coverage implementation #125756.
Allow constraining opaque types during subtyping in the trait system
Previous attempt: https://github.com/rust-lang/rust/pull/123979
Sometimes we don't immediately perform subtyping, but instead register a subtyping obligation and solve that obligation when its inference variables become resolved. Unlike immediate subtyping, we currently do not allow registering hidden types for opaque types. This PR also allows that.
It now parses outer attributes before collecting tokens. This avoids the
problem where the outer attribute tokens were being stored twice -- for
the attribute tokesn, and also for the expression tokens.
Fixes#86055.
Rollup of 7 pull requests
Successful merges:
- #123782 (Test that opaque types can't have themselves as a hidden type with incompatible lifetimes)
- #124580 (Suggest removing unused tuple fields if they are the last fields)
- #125787 (Migrate `bin-emit-no-symbols` `run-make` test to `rmake`)
- #126553 (match lowering: expand or-candidates mixed with candidates above)
- #126594 (Make async drop code more consistent with regular drop code)
- #126654 (Make pretty printing for `f16` and `f128` consistent)
- #126656 (rustc_type_ir: Omit some struct fields from Debug output)
r? `@ghost`
`@rustbot` modify labels: rollup
match lowering: expand or-candidates mixed with candidates above
This PR tweaks match lowering of or-patterns. Consider this:
```rust
match (x, y) {
(1, true) => 1,
(2, false) => 2,
(1 | 2, true | false) => 3,
(3 | 4, true | false) => 4,
_ => 5,
}
```
One might hope that this can be compiled to a single `SwitchInt` on `x` followed by some boolean checks. Before this PR, we compile this to 3 `SwitchInt`s on `x`, because an arm that contains more than one or-pattern was compiled on its own. This PR groups branch `3` with the two branches above, getting us down to 2 `SwitchInt`s on `x`.
We can't in general expand or-patterns freely, because this interacts poorly with another optimization we do: or-pattern simplification. When an or-pattern doesn't involve bindings, we branch the success paths of all its alternatives to the same block. The drawback is that in a case like:
```rust
match (1, true) {
(1 | 2, false) => unreachable!(),
(2, _) => unreachable!(),
_ => {}
}
```
if we used a single `SwitchInt`, by the time we test `false` we don't know whether we came from the `1` case or the `2` case, so we don't know where to go if `false` doesn't match.
Hence the limitation: we can process or-pattern alternatives alongside candidates that precede it, but not candidates that follow it. (Unless the or-pattern is the only remaining match pair of its candidate, in which case we can process it alongside whatever).
This PR allows the processing of or-pattern alternatives alongside candidates that precede it. One benefit is that we now process or-patterns in a single place in `mod.rs`.
r? ``@matthewjasper``
Suggest removing unused tuple fields if they are the last fields
Fixes#124556
We now check if dead/unused fields are the last fields of the tuple and suggest their removal instead of suggesting them to be changed to `()`.
Test that opaque types can't have themselves as a hidden type with incompatible lifetimes
fixes#122876
This PR used to add extra logic to prevent those cases, but after https://github.com/rust-lang/rust/pull/113169 this is implicitly rejected, because such usages are not defining.
improve tip for inaccessible traits
Improve the tips when the candidate method is from an inaccessible trait.
For example:
```rs
mod m {
trait Trait {
fn f() {}
}
impl<T> Trait for T {}
}
fn main() {
struct S;
S::f();
}
```
The difference between before and now is:
```diff
error[E0599]: no function or associated item named `f` found for struct `S` in the current scope
--> ./src/main.rs:88:6
|
LL | struct S;
| -------- function or associated item `f` not found for this struct
LL | S::f();
| ^ function or associated item not found in `S`
|
= help: items from traits can only be used if the trait is implemented and in scope
- help: trait `Trait` which provides `f` is implemented but not in scope; perhaps you want to import it
+ help: trait `crate:Ⓜ️:Trait` which provides `f` is implemented but not reachable
|
- LL + use crate:Ⓜ️:Trait;
|
```
hir_typeck: be more conservative in making "note caller chooses ty param" note
In https://github.com/rust-lang/rust/pull/122195 I added a "caller chooses ty for type param" note for when the return expression type a.k.a. found type does not match the expected return type.
#126547 found that this note was confusing when the found return type *contains* the expected type, e.g.
```rs
fn f<T>(t: &T) -> T {
t
}
```
because the found return type `&T` will *always* be different from the expected return type `T`, so the note was needlessly redundant and confusing.
This PR addresses that by not making the note if the found return type contains the expected return type.
r? ``@fmease`` (since you reviewed the original PR)
Fixes https://github.com/rust-lang/rust/issues/126547
safe transmute: support non-ZST, variantful, uninhabited enums
Previously, `Tree::from_enum`'s implementation branched into three disjoint cases:
1. enums that uninhabited
2. enums for which all but one variant is uninhabited
3. enums with multiple variants
This branching (incorrectly) did not differentiate between variantful and variantless uninhabited enums. In both cases, we assumed (and asserted) that uninhabited enums are zero-sized types. This assumption is false for enums like:
enum Uninhabited { A(!, u128) }
...which, currently, has the same size as `u128`. This faulty assumption manifested as the ICE reported in #126460.
In this PR, we revise the first case of `Tree::from_enum` to consider only the narrow category of "enums that are uninhabited ZSTs". These enums, whose layouts are described with `Variants::Single { index }`, are special in their layouts otherwise resemble the `!` type and cannot be descended into like typical enums. This first case captures uninhabited enums like:
enum Uninhabited { A(!, !), B(!) }
The second case is revised to consider the broader category of "enums that defer their layout to one of their variants"; i.e., enums whose layouts are described with `Variants::Single { index }` and that do have a variant at `index`. This second case captures uninhabited enums that are not ZSTs, like:
enum Uninhabited { A(!, u128) }
...which represent their variants with `Variants::Single`.
Finally, the third case is revised to cover the broader category of "enums with multiple variants", which captures uninhabited enums like:
enum Uninhabited { A(u8, !), B(!, u32) }
...which represent their variants with `Variants::Multiple`.
This PR also adds a comment requested by ````@RalfJung```` in his review of #126358 to `compiler/rustc_const_eval/src/interpret/discriminant.rs`.
Fixes#126460
r? ````@compiler-errors````
Suggest using a standalone doctest for non-local impl defs
This PR tweaks the lint output of the `non_local_definitions` lint to suggest using a standalone doctest instead of a moving the `impl` def to an impossible place as was already done with `macro_rules!` case in https://github.com/rust-lang/rust/pull/124568.
Fixes#126339
r? ```@fmease```
Place tail expression behind terminating scope
This PR implements #123739 so that we can do further experiments in nightly.
A little rewrite has been applied to `for await` lowering. It was previously `unsafe { Pin::unchecked_new(into_async_iter(..)) }`. Under the edition 2024 rule, however, `into_async_iter` gets dropped at the end of the `unsafe` block. This presumably the first Edition 2024 migration rule goes by hoisting `into_async_iter(..)` into `match` one level above, so it now looks like the following.
```rust
match into_async_iter($iter_expr) {
ref mut iter => match unsafe { Pin::unchecked_new(iter) } {
...
}
}
```
delegation: Implement glob delegation
Support delegating to all trait methods in one go.
Overriding globs with explicit definitions is also supported.
The implementation is generally based on the design from https://github.com/rust-lang/rfcs/pull/3530#issuecomment-2020869823, but unlike with list delegation in https://github.com/rust-lang/rust/pull/123413 we cannot expand glob delegation eagerly.
We have to enqueue it into the queue of unexpanded macros (most other macros are processed this way too), and then a glob delegation waits in that queue until its trait path is resolved, and enough code expands to generate the identifier list produced from the glob.
Glob delegation is only allowed in impls, and can only point to traits.
Supporting it in other places gives very little practical benefit, but significantly raises the implementation complexity.
Part of https://github.com/rust-lang/rust/issues/118212.
Replace all `&DiagCtxt` with a `DiagCtxtHandle<'_>` wrapper type
r? `@davidtwco`
This paves the way for tracking more state (e.g. error tainting) in the diagnostic context handle
Basically I will add a field to the `DiagCtxtHandle` that refers back to the `InferCtxt`'s (and others) `Option<ErrorHandled>`, allowing us to immediately taint these contexts when emitting an error and not needing manual tainting anymore (which is easy to forget and we don't do in general anyway)
