Restore `#![no_builtins]` crates participation in LTO.
After #113716, we can make `#![no_builtins]` crates participate in LTO again.
`#![no_builtins]` with LTO does not result in undefined references to the error. I believe this type of issue won't happen again.
Fixes#72140. Fixes#112245. Fixes#110606. Fixes#105734. Fixes#96486. Fixes#108853. Fixes#108893. Fixes#78744. Fixes#91158. Fixes https://github.com/rust-lang/cargo/issues/10118. Fixes https://github.com/rust-lang/compiler-builtins/issues/347.
The `nightly-2023-07-20` version does not always reproduce problems due to changes in compiler-builtins, core, and user code. That's why this issue recurs and disappears.
Some issues were not tested due to the difficulty of reproducing them.
r? pnkfelix
cc `@bjorn3` `@japaric` `@alexcrichton` `@Amanieu`
Liveness data is pushed from multiple parts of NLL. Instead of changing
the call sites to maintain live loans, move the latter to `LivenessValues` where
this liveness data is pushed to, and maintain live loans there.
This fixes the differences in polonius scopes on some CFGs where a
variable was dead in tracing but as a MIR terminator its regions were marked
live from "constraint generation"
Stabilize C string literals
RFC: https://rust-lang.github.io/rfcs/3348-c-str-literal.html
Tracking issue: https://github.com/rust-lang/rust/issues/105723
Documentation PR (reference manual): https://github.com/rust-lang/reference/pull/1423
# Stabilization report
Stabilizes C string and raw C string literals (`c"..."` and `cr#"..."#`), which are expressions of type [`&CStr`](https://doc.rust-lang.org/stable/core/ffi/struct.CStr.html). Both new literals require Rust edition 2021 or later.
```rust
const HELLO: &core::ffi::CStr = c"Hello, world!";
```
C strings may contain any byte other than `NUL` (`b'\x00'`), and their in-memory representation is guaranteed to end with `NUL`.
## Implementation
Originally implemented by PR https://github.com/rust-lang/rust/pull/108801, which was reverted due to unintentional changes to lexer behavior in Rust editions < 2021.
The current implementation landed in PR https://github.com/rust-lang/rust/pull/113476, which restricts C string literals to Rust edition >= 2021.
## Resolutions to open questions from the RFC
* Adding C character literals (`c'.'`) of type `c_char` is not part of this feature.
* Support for `c"..."` literals does not prevent `c'.'` literals from being added in the future.
* C string literals should not be blocked on making `&CStr` a thin pointer.
* It's possible to declare constant expressions of type `&'static CStr` in stable Rust (as of v1.59), so C string literals are not adding additional coupling on the internal representation of `CStr`.
* The unstable `concat_bytes!` macro should not accept `c"..."` literals.
* C strings have two equally valid `&[u8]` representations (with or without terminal `NUL`), so allowing them to be used in `concat_bytes!` would be ambiguous.
* Adding a type to represent C strings containing valid UTF-8 is not part of this feature.
* Support for a hypothetical `&Utf8CStr` may be explored in the future, should such a type be added to Rust.
Refactor NLL constraint generation and most of polonius fact generation
As discussed in #118175, NLL "constraint generation" is only about liveness, but currently also contains legacy polonius fact generation. The latter is quite messy, and this PR cleans this up to prepare for its future removal:
- splits polonius fact generation out of NLL constraint generation
- merges NLL constraint generation to its more natural place, liveness
- extracts all of the polonius fact generation from NLLs apart from MIR typeck (as fact generation is somewhat in a single place there already, but should be cleaned up) into its own explicit module, with a single entry point instead of many.
There should be no behavior changes, and tests seem to behave the same as master: without polonius, with legacy polonius, with the in-tree polonius.
I've split everything into smaller logical commits for easier review, as it required quite a bit of code to be split and moved around, but it should all be trivial changes.
r? `@matthewjasper`
Rollup of 3 pull requests
Successful merges:
- #118483 (rustdoc: `div.where` instead of fmt-newline class)
- #118486 (generic_const_exprs: suggest to add the feature, not use it)
- #118489 (Wesley is on vacation)
r? `@ghost`
`@rustbot` modify labels: rollup
generic_const_exprs: suggest to add the feature, not use it
Usually our missing feature messages look something like
```
= help: add `#![feature(inline_const)]` to the crate attributes to enable
```
However `generic_const_exprs` used a different verb. That's inconsistent and it also means playground won't add that nice hyperlink to add the feature automatically. So let's use the same verb as everywhere else.
explain a good reason for why LocalValue does not store the type of the local
As found out by `@lcnr` in https://github.com/rust-lang/rust/pull/112307, storing the type here can lead to subtle bugs when it gets out of sync with the MIR body. That's not the reason why the interpreter does it this way I think, but good thing we dodged that bullet. :)
Change `SwitchTarget` representation in StableMIR
The new structure encodes its invariant, which reduces the likelihood of having an inconsistent representation. It is also more intuitive and user friendly.
I encapsulated the structure for now in case we decide to change it back.
### Notes:
1. I had to change the `Successors` type, since there's a conflict on the iterator type. We could potentially implement an iterator here, but I would prefer keeping it simple for now, and add a `successors_iter()` method if needed.
2. I removed `CoroutineDrop` for now since it we never create it. We can add it when we add support to other MIR stages.
Add `-Zfunction-return={keep,thunk-extern}` option
This is intended to be used for Linux kernel RETHUNK builds.
With this commit (optionally backported to Rust 1.73.0), plus a patched Linux kernel to pass the flag, I get a RETHUNK build with Rust enabled that is `objtool`-warning-free and is able to boot in QEMU and load a sample Rust kernel module.
Issue: https://github.com/rust-lang/rust/issues/116853.
On Fn arg mismatch for a fn path, suggest a closure
When encountering a fn call that has a path to another fn being passed in, where an `Fn` impl is expected, and the arguments differ, suggest wrapping the argument with a closure with the appropriate arguments.
The last `help` is new:
```
error[E0631]: type mismatch in function arguments
--> $DIR/E0631.rs:9:9
|
LL | fn f(_: u64) {}
| ------------ found signature defined here
...
LL | foo(f);
| --- ^ expected due to this
| |
| required by a bound introduced by this call
|
= note: expected function signature `fn(usize) -> _`
found function signature `fn(u64) -> _`
note: required by a bound in `foo`
--> $DIR/E0631.rs:3:11
|
LL | fn foo<F: Fn(usize)>(_: F) {}
| ^^^^^^^^^ required by this bound in `foo`
help: consider wrapping the function in a closure
|
LL | foo(|arg0: usize| f(/* u64 */));
| +++++++++++++ +++++++++++
```
The new structure encodes its invariant, which reduces the likelihood
of having an inconsistent representation. It is also more intuitive and
user friendly.
I encapsulated the structure for now in case we decide to change it back.
This is intended to be used for Linux kernel RETHUNK builds.
With this commit (optionally backported to Rust 1.73.0), plus a
patched Linux kernel to pass the flag, I get a RETHUNK build with
Rust enabled that is `objtool`-warning-free and is able to boot in
QEMU and load a sample Rust kernel module.
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Dispose llvm::TargetMachines prior to llvm::Context being disposed
If the TargetMachine is disposed after the Context is disposed, it can lead to use after frees in some cases.
I've observed this happening occasionally on code compiled for aarch64-pc-windows-msvc using `-Zstack-protector=strong` but other users have reported AVs from host aarch64-pc-windows-msvc compilers as well.
I was not able to extract a self-contained test case yet so there is no accompanying test.
Fixes#118462
rustc_span: Remove unused symbols.
As noted here, there is no guarantee that all pre-interned symbols are used.
b10cfcd65f/compiler/rustc_span/src/symbol.rs (L124-L125)
This was done starting with using ripgrep to search for `sym::whatever`. I removed anything that didn't show up. However this had a huge number of false positives, due to extensive macro use. Then there was a manual phase of adding back all the ones used my macros.
I don't think this was worth my time to do, but it's done now . ¯\_(ツ)_/¯
Tweak message on ADT with private fields building
When trying to create an inaccessible ADT due to private fields, handle the case when no fields were passed.
```
error: cannot construct `Foo` with struct literal syntax due to private fields
--> $DIR/issue-76077.rs:8:5
|
LL | foo::Foo {};
| ^^^^^^^^
|
= note: private field `you_cant_use_this_field` that was not provided
```
miri: add test checking that aggregate assignments reset memory to uninit
Also, `write_aggregate` is really just a helper for evaluating `Aggregate` rvalues, so it should be in `step.rs`, not `place.rs`. Also factor out `Repeat` rvalues into their own function while we are at it.
r? `@saethlin`
Fixes https://github.com/rust-lang/miri/issues/3195
They're not used in `rustc_session`, and `rustc_metadata` is a more
obvious location.
`MetadataLoader` was originally put into `rustc_session` in #41565 to
avoid a dependency on LLVM, but things have changed a lot since then and
that's no longer relevant, e.g. `rustc_codegen_llvm` depends on
`rustc_metadata`.
Fix `PartialEq` args when `#[const_trait]` is enabled
This is based off of your PR that enforces effects on all methods, so just see the last commits.
r? fee1-dead
Tweak parsing recovery of enums, for exprs and match arm patterns
Tweak recovery of `for (pat in expr) {}` for more accurate spans.
When encountering `match` arm `(pat if expr) => {}`, recover and suggest removing parentheses. Fix#100825.
When encountering malformed enums, try more localized per-variant parse recovery.
Move parser recovery tests to subdirectory.
If the TargetMachine is disposed after the Context is disposed, it can
lead to use after frees in some cases.
I've observed this happening occasionally on code compiled for
aarch64-pc-windows-msvc using `-Zstack-protector=strong` but other users
have reported AVs from host aarch64-pc-windows-msvc compilers as well.
Pass +forced-atomics feature for riscv32{i,im,imc}-unknown-none-elf
As said in https://github.com/rust-lang/rust/pull/98333#issuecomment-1666375293, `forced-atomics` target feature is also needed to enable atomic load/store on these targets (otherwise, libcalls are generated): https://godbolt.org/z/433qeG7vd
~~This PR is currently marked as a draft because:~~
- ~~`forced-atomics` target feature is currently broken (https://github.com/rust-lang/rust/issues/114153).~~ EDIT: Fixed
- ~~`forced-atomics` target feature has been added in LLVM 16 (f5ed0cb217), but the current minimum LLVM version [is 15](90f0b24ad3/src/bootstrap/llvm.rs (L557)). In LLVM 15, the atomic load/store of these targets generates libcalls anyway.~~ EDIT: LLVM 15 has been dropped
Depending on the policy on the minimum LLVM version for these targets, this may be blocked until the minimum LLVM version is increased to 16.
r? `@Amanieu`
When encountering a fn call that has a path to another fn being passed
in, where an `Fn` impl is expected, and the arguments differ, suggest
wrapping the argument with a closure with the appropriate arguments.
When trying to create an inaccessible ADT due to private fields, handle
the case when no fields were passed.
```
error: cannot construct `Foo` with struct literal syntax due to private fields
--> $DIR/issue-76077.rs:8:5
|
LL | foo::Foo {};
| ^^^^^^^^
|
= note: private field `you_cant_use_this_field` that was not provided
```
ConstProp: Correctly remove const if unknown value assigned to it.
Closes#118328
The problematic sequence of MIR is:
```rust
_1 = const 0_usize;
_1 = const _; // This is an associated constant we can't know before monomorphization.
_0 = _1;
```
1. When `ConstProp::visit_assign` happens on `_1 = const 0_usize;`, it records that `0x0usize` is the value for `_1`.
2. Next `visit_assign` happens on `_1 = const _;`. Because the rvalue `.has_param()`, it can't be const evaled.
3. Finaly, `visit_assign` happens on `_0 = _1;`. Here it would think the value of `_1` was `0x0usize` from step 1.
The solution is to remove consts when checking the RValue fails, as they may have contained values that should now be invalidated, as that local was overwritten.
This should probably be back-ported to beta. Stable is more iffy, as it's gone unidentified since 1.70, so I only think it's worthwhile if there's another reason for a 1.74.1 release anyway.
Suggest `let` or `==` on typo'd let-chain
When encountering a bare assignment in a let-chain, suggest turning the
assignment into a `let` expression or an equality check.
```
error: expected expression, found `let` statement
--> $DIR/bad-if-let-suggestion.rs:5:8
|
LL | if let x = 1 && i = 2 {}
| ^^^^^^^^^
|
= note: only supported directly in conditions of `if` and `while` expressions
help: you might have meant to continue the let-chain
|
LL | if let x = 1 && let i = 2 {}
| +++
help: you might have meant to compare for equality
|
LL | if let x = 1 && i == 2 {}
| +
```
Add `never_patterns` feature gate
This PR adds the feature gate and most basic parsing for the experimental `never_patterns` feature. See the tracking issue (https://github.com/rust-lang/rust/issues/118155) for details on the experiment.
`@scottmcm` has agreed to be my lang-team liaison for this experiment.
Rollup of 7 pull requests
Successful merges:
- #118342 (Dont suggest `!` for path in function call if it has generic args)
- #118383 (Address unused tuple struct fields in the standard library)
- #118401 (`rustc_ast_lowering` cleanups)
- #118409 (format_foreign.rs: unwrap return Option value for `fn position`, as it always returns Some)
- #118413 (Fix the issue of suggesting unwrap/expect for shorthand field)
- #118425 (Update cargo)
- #118429 (Fix a typo in a `format_args!` note)
r? `@ghost`
`@rustbot` modify labels: rollup
format_foreign.rs: unwrap return Option value for `fn position`, as it always returns Some
Trivial cleanup.
It will be nice to have way to run exhaustiveness analysis on similar cases to see dead code.
Fix coroutine validation for mixed panic strategy
Validation introduced in #113124 allows `UnwindAction::Continue` and `TerminatorKind::Resume` to occur only in functions with ABI that can unwind. The function ABI depends on the panic strategy, which can vary across crates.
Usually MIR is built and validated in the same crate. The coroutine drop glue thus far was an exception. As a result validation could fail when mixing different panic strategies.
Avoid the problem by executing `AbortUnwindingCalls` along with the validation.
Fixes#116953.
Eagerly return `ExprKind::Err` on `yield`/`await` in wrong coroutine context
This PR does 2 things:
1. Refuses to lower `.await` or `yield` when we are outside of the right coroutine context for the operator. Instead, we lower to `hir::ExprKind::Err`, to silence subsequent redundant errors.
2. Reworks a bit of the span tracking in `LoweringContext` to fix a bad span when we have something like `let x = [0; async_fn().await]` where the `await` is inside of an anon const. The span for the "item" still kinda sucks, since it overlaps with the `await` span, but at least it's accurate.
Remove HIR opkinds
`hir::BinOp`, `hir::BinOpKind`, and `hir::UnOp` are identical to `ast::BinOp`, `ast::BinOpKind`, and `ast::UnOp`, respectively. This seems silly, so this PR removes the HIR ones. (A re-export lets the AST ones be referred to using a `hir::` qualifier, which avoids renaming churn.)
r? `@cjgillot`
Unify `TraitRefs` and `PolyTraitRefs` in `ValuePairs`
I did this recently with `FnSigs` and `PolyFnSigs` but didn't think to do it with `TraitRefs` and `PolyTraitRefs`.
Cut code size for feature hashing
This locally cuts ~32 kB of .text instructions.
This isn't really a clear win in terms of readability. IMO the code size benefits are worth it (even if they're not necessarily present in the x86_64 hyperoptimized build, I expect them to translate similarly to other platforms). Ultimately there's lots of "small ish" low hanging fruit like this that I'm seeing that seems worth tackling to me, and could translate into larger wins in aggregate.
Rollup of 6 pull requests
Successful merges:
- #118193 (Add missing period in `std::process::Command` docs)
- #118222 (unify read_to_end and io::copy impls for reading into a Vec)
- #118323 (give dev-friendly error message for incorrect config profiles)
- #118378 (Perform LTO optimisations with wasm-ld + -Clinker-plugin-lto)
- #118399 (Clean dead codes in miri)
- #118410 (update test for new LLVM 18 codegen)
r? `@ghost`
`@rustbot` modify labels: rollup
Validation introduced in #113124 allows UnwindAction::Continue and
TerminatorKind::Resume to occur only in functions with ABI that can
unwind. The function ABI depends on the panic strategy, which can vary
across crates.
Usually MIR is built and validated in the same crate. The coroutine drop
glue thus far was an exception. As a result validation could fail when
mixing different panic strategies.
Avoid the problem by executing AbortUnwindingCalls along with the
validation.
When encountering a bare assignment in a let-chain, suggest turning the
assignment into a `let` expression or an equality check.
```
error: expected expression, found `let` statement
--> $DIR/bad-if-let-suggestion.rs:5:8
|
LL | if let x = 1 && i = 2 {}
| ^^^^^^^^^
|
= note: only supported directly in conditions of `if` and `while` expressions
help: you might have meant to continue the let-chain
|
LL | if let x = 1 && let i = 2 {}
| +++
help: you might have meant to compare for equality
|
LL | if let x = 1 && i == 2 {}
| +
```
Perform LTO optimisations with wasm-ld + -Clinker-plugin-lto
Fixes (partially) #60059. Technically, `--target wasm32-unknown-unknown -Clinker-plugin-lto` would complete without errors before, but it was not producing optimized code. At least, it may have been but it was probably not the opt-level people intended.
Similarly to #118377, this could benefit from a warning about using an explicit libLTO path with LLD, which will ignore it and use its internal LLVM. Especially given we always use lld on wasm targets. I left the code open to that possibility rather than making it perfectly neat.
effects: Run `enforce_context_effects` for all method calls
So that we also perform checks when overloaded `PartialEq`s are called.
r? `@compiler-errors`
They're identical to the same-named types from `ast`. I find it silly
(and inefficient) to have all this boilerplate code to convert one type
to an identical type.
There is already a small amount of type sharing between the AST and HIR,
e.g. `Attribute`, `MacroDef`.
The commit adds a `pub use` to `rustc_hir` so that, for example,
`ast::BinOp` can also be referred to as `hir::BinOp`. This is so the
many existing `hir`-qualified mentions of these types don't need to
change.
The commit also moves a couple of operations from the (removed) HIR
types to the AST types, e.g. `is_by_value`.
rustc_span: Use correct edit distance start length for suggestions
Otherwise the suggestions can be off-base for non-ASCII identifiers. For example suggesting that `Ok` is a name similar to `读文`.
Closes https://github.com/rust-lang/rust/issues/72553.
QueryContext: rename try_collect_active_jobs -> collect_active_jobs, change return type from Option<QueryMap> to QueryMap
As there currently always Some(...) inside.
Added linker_arg(s) Linker trait methods for link-arg to be prefixed "-Wl," for cc-like linker args and not verbatim
https://github.com/rust-lang/rust/issues/99427#issuecomment-1234443468
> here's one possible improvement to -l link-arg making it more portable between linkers and useful - befriending it with the verbatim modifier (https://github.com/rust-lang/rust/issues/99425).
>
> -l link-arg:-verbatim=-foo would add -Wl,-foo (or equivalent) when C compiler is used as a linker, and just -foo when bare linker is used.
> -l link-arg:+verbatim=-bar on the other hand would always pass just -bar.
Add `pretty_terminator` to pretty stable-mir
~Because we don't have successors in `stable_mir` this is somewhat lacking but it's better than nothing~, also fixed bug(?) with `Opaque` which printed extra `"` when we try to print opaqued `String`.
**Edit**: Added successors so this covers Terminators as a whole.
r? `@celinval`
Account for `!` arm in tail `match` expr
On functions with a default return type that influences the coerced type of `match` arms, check if the failing arm is actually of type `!`. If so, suggest changing the return type so the coercion against the prior arms is successful.
```
error[E0308]: `match` arms have incompatible types
--> $DIR/match-tail-expr-never-type-error.rs:9:13
|
LL | fn bar(a: bool) {
| - help: try adding a return type: `-> i32`
LL | / match a {
LL | | true => 1,
| | - this is found to be of type `{integer}`
LL | | false => {
LL | | never()
| | ^^^^^^^
| | |
| | expected integer, found `()`
| | this expression is of type `!`, but it get's coerced to `()` due to its surrounding expression
LL | | }
LL | | }
| |_____- `match` arms have incompatible types
```
Fix#24157.
- Rename them both `as_str`, which is the typical name for a function
that returns a `&str`. (`to_string` is appropriate for functions
returning `String` or maybe `Cow<'a, str>`.)
- Change `UnOp::as_str` from an associated function (weird!) to a
method.
- Avoid needless `self` dereferences.
Do not erase late bound regions when selecting inherent associated types
In the fix for #97156 we would want the following code:
```rust
#![feature(inherent_associated_types)]
#![allow(incomplete_features)]
struct Foo<T>(T);
impl Foo<fn(&'static ())> {
type Assoc = u32;
}
trait Other {}
impl Other for u32 {}
// FIXME(inherent_associated_types): Avoid emitting two diagnostics (they only differ in span).
// FIXME(inherent_associated_types): Enhancement: Spruce up the diagnostic by saying something like
// "implementation is not general enough" as is done for traits via
// `try_report_trait_placeholder_mismatch`.
fn bar(_: Foo<for<'a> fn(&'a ())>::Assoc) {}
//~^ ERROR mismatched types
//~| ERROR mismatched types
fn main() {}
```
to fail with ...
```
error[E0220]: associated type `Assoc` not found for `Foo<for<'a> fn(&'a ())>` in the current scope
--> tests/ui/associated-inherent-types/issue-109789.rs:18:36
|
4 | struct Foo<T>(T);
| ------------- associated item `Assoc` not found for this struct
...
18 | fn bar(_: Foo<for<'a> fn(&'a ())>::Assoc) {}
| ^^^^^ associated item not found in `Foo<for<'a> fn(&'a ())>`
|
= note: the associated type was found for
- `Foo<fn(&'static ())>`
error: aborting due to previous error
For more information about this error, try `rustc --explain E0220`.
```
This PR fixes the ICE we are currently getting "was a subtype of Foo<Binder(fn(&ReStatic ()), [])> during selection but now it is not"
Also fixes#112631
r? `@lcnr`
On functions with a default return type that influences the coerced type
of `match` arms, check if the failing arm is actually of type `!`. If
so, suggest changing the return type so the coercion against the prior
arms is successful.
```
error[E0308]: `match` arms have incompatible types
--> $DIR/match-tail-expr-never-type-error.rs:9:13
|
LL | fn bar(a: bool) {
| - help: try adding a return type: `-> i32`
LL | / match a {
LL | | true => 1,
| | - this is found to be of type `{integer}`
LL | | false => {
LL | | never()
| | ^^^^^^^
| | |
| | expected integer, found `()`
| | this expression is of type `!`, but it get's coerced to `()` due to its surrounding expression
LL | | }
LL | | }
| |_____- `match` arms have incompatible types
```
Fix#24157.
Suggest swapping the order of `ref` and `box`
It is not valid grammar to write `ref box <ident>` in patterns, but `box ref <ident>` is.
This patch adds a diagnostic to suggest swapping them, analogous to what we do for `mut let`.
Enable the Arm Cortex-A53 errata mitigation on aarch64-unknown-none
Arm Cortex-A53 CPUs have an errata related to a specific sequence of instructions - errata number 843419 (https://documentation-service.arm.com/static/5fa29fddb209f547eebd361d). There is a mitigation that can be applied at link-time which detects the when sequence of instructions exists at a specific alignment. When detected, the linker re-writes those instructions and either changes an ADRP to an ADR, or bounces to a veneer to break the sequence.
The linker argument to enable the mitigation is "--fix-cortex-a53-843419", and this is supported by GNU ld and LLVM lld. The gcc argument to enable the flag is "-mfix-cortex-a53-843419".
Because the aarch64-unknown-none target uses rust-lld directly, this patch causes rustc to emit the "--fix-cortex-a53-843419" argument when calling the linker, just like aarch64-linux-gnu-gcc on Ubuntu 22.04 does.
Failure to enable this mitigation in the linker can cause the production of instruction sequences that do not execute correctly on Arm Cortex-A53.
