Rollup of 5 pull requests #148496
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Rollup of 5 pull requests #148496
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The tests fail on s390x and presumably other big-endian systems, due to check of raw alloc values in the MIR output. To fix the tests remove the raw bytes from the MIR output (via: compile-flags: -Zdump-mir-exclude-alloc-bytes) and update the matching diffs.
This implements a new unstable compiler flag `-Zannotate-moves` that makes
move and copy operations visible in profilers by creating synthetic debug
information. This is achieved with zero runtime cost by manipulating debug
info scopes to make moves/copies appear as calls to `compiler_move<T, SIZE>`
and `compiler_copy<T, SIZE>` marker functions in profiling tools.
This allows developers to identify expensive move/copy operations in their
code using standard profiling tools, without requiring specialized tooling
or runtime instrumentation.
The implementation works at codegen time. When processing MIR operands
(`Operand::Move` and `Operand::Copy`), the codegen creates an `OperandRef`
with an optional `move_annotation` field containing an `Instance` of the
appropriate profiling marker function. When storing the operand,
`store_with_annotation()` wraps the store operation in a synthetic debug
scope that makes it appear inlined from the marker.
Two marker functions (`compiler_move` and `compiler_copy`) are defined
in `library/core/src/profiling.rs`. These are never actually called -
they exist solely as debug info anchors.
Operations are only annotated if the type:
- Meets the size threshold (default: 65 bytes, configurable via
`-Zannotate-moves=SIZE`)
- Has a non-scalar backend representation (scalars use registers,
not memcpy)
This has a very small size impact on object file size. With the default
limit it's well under 0.1%, and even with a very small limit of 8 bytes
it's still ~1.5%. This could be enabled by default.
The first was a warning:
```
Testing stage2 {rustc_parse_format} (aarch64-apple-darwin)
Compiling rustc_index v0.0.0 (/Users/ci/project/compiler/rustc_index)
error: extern crate `smallvec` is unused in crate `rustc_index`
--> compiler/rustc_index/src/lib.rs:2:1
|
2 | #![cfg_attr(all(feature = "nightly", test), feature(stmt_expr_attributes))]
| ^
|
= help: remove the dependency or add `use smallvec as _;` to the crate root
= note: `-D unused-crate-dependencies` implied by `-D warnings`
= help: to override `-D warnings` add `#[allow(unused_crate_dependencies)]`
error: could not compile `rustc_index` (lib) due to 1 previous error
```
The second was that `type_ir_macros` didn't fully specify its
dependencies:
```
Testing stage1 {rustc_type_ir_macros} (aarch64-apple-darwin)
Compiling rustc_type_ir_macros v0.0.0 (/Users/jyn/src/ferrocene3/compiler/rustc_type_ir_macros)
error[E0432]: unresolved import `syn::visit_mut`
--> compiler/rustc_type_ir_macros/src/lib.rs:2:10
|
2 | use syn::visit_mut::VisitMut;
| ^^^^^^^^^ could not find `visit_mut` in `syn`
|
note: found an item that was configured out
--> /Users/jyn/.local/lib/cargo/registry/src/index.crates.io-1949cf8c6b5b557f/syn-2.0.106/src/lib.rs:880:21
|
878 | #[cfg(feature = "visit-mut")]
| --------------------- the item is gated behind the `visit-mut` feature
879 | #[cfg_attr(docsrs, doc(cfg(feature = "visit-mut")))]
880 | pub use crate::gen::visit_mut;
| ^^^^^^^^^
error[E0433]: failed to resolve: could not find `visit_mut` in `syn`
--> compiler/rustc_type_ir_macros/src/lib.rs:206:18
|
206 | syn::visit_mut::visit_type_path_mut(self, i);
| ^^^^^^^^^ could not find `visit_mut` in `syn`
|
note: found an item that was configured out
--> /Users/jyn/.local/lib/cargo/registry/src/index.crates.io-1949cf8c6b5b557f/syn-2.0.106/src/lib.rs:880:21
|
878 | #[cfg(feature = "visit-mut")]
| --------------------- the item is gated behind the `visit-mut` feature
879 | #[cfg_attr(docsrs, doc(cfg(feature = "visit-mut")))]
880 | pub use crate::gen::visit_mut;
| ^^^^^^^^^
```
Previously we only showed the trait's assoc item if the trait was local, because we were looking for a small span only for the generics, which we don't have for foreign traits. We now use `def_span` for the item, so we at least provide some context, even if its span is too wide.
```
error[E0195]: lifetime parameters or bounds on type `IntoIter` do not match the trait declaration
--> tests/ui/lifetimes/missing-lifetime-in-assoc-type-4.rs:7:18
|
7 | type IntoIter<'a> = std::collections::btree_map::Values<'a, i32, T>;
| ^^^^ lifetimes do not match type in trait
|
::: /home/gh-estebank/rust/library/core/src/iter/traits/collect.rs:292:5
|
292 | type IntoIter: Iterator<Item = Self::Item>;
| ------------------------------------------ lifetimes in impl do not match this type in trait
```
Given an associated item that needs a named lifetime, look at the enclosing `impl` item for one. If there is none, look at the self type and the implemented trait to see if either of those has an anonimous lifetime. If so, suggest adding a named lifetime.
```
error: in the trait associated type is declared without lifetime parameters, so using a borrowed type for them requires that lifetime to come from the implemented type
--> $DIR/missing-lifetime-in-assoc-type-2.rs:5:17
|
LL | type Item = &T;
| ^ this lifetime must come from the implemented type
|
help: add a lifetime to the impl block and use it in the self type and associated type
|
LL ~ impl<'a> IntoIterator for &'a S {
LL ~ type Item = &'a T;
|
```
Move the previous long message to a note and use a shorter primary message:
```
error: missing lifetime in associated type
--> $DIR/missing-lifetime-in-assoc-type-1.rs:9:17
|
LL | impl<'a> IntoIterator for &S {
| ---- there is a named lifetime specified on the impl block you could use
...
LL | type Item = &T;
| ^ this lifetime must come from the implemented type
|
note: in the trait the associated type is declared without lifetime parameters, so using a borrowed type for them requires that lifetime to come from the implemented type
--> $SRC_DIR/core/src/iter/traits/collect.rs:LL:COL
help: consider using the lifetime from the impl block
|
LL | type Item = &'a T;
| ++
```
…eril Tweak output of missing lifetime on associated type Follow up to rust-lang#135602. Previously we only showed the trait's assoc item if the trait was local, because we were looking for a small span only for the generics, which we don't have for foreign traits. We now use `def_span` for the item, so we at least provide some context, even if its span is too wide. ``` error[E0195]: lifetime parameters or bounds on type `IntoIter` do not match the trait declaration --> tests/ui/lifetimes/missing-lifetime-in-assoc-type-4.rs:7:18 | 7 | type IntoIter<'a> = std::collections::btree_map::Values<'a, i32, T>; | ^^^^ lifetimes do not match type in trait | ::: /home/gh-estebank/rust/library/core/src/iter/traits/collect.rs:292:5 | 292 | type IntoIter: Iterator<Item = Self::Item>; | ------------------------------------------ lifetimes in impl do not match this type in trait ``` Given an associated item that needs a named lifetime, look at the enclosing `impl` item for one. If there is none, look at the self type and the implemented trait to see if either of those has an anonimous lifetime. If so, suggest adding a named lifetime. ``` error: in the trait associated type is declared without lifetime parameters, so using a borrowed type for them requires that lifetime to come from the implemented type --> $DIR/missing-lifetime-in-assoc-type-2.rs:5:17 | LL | type Item = &T; | ^ this lifetime must come from the implemented type | help: add a lifetime to the impl block and use it in the self type and associated type | LL ~ impl<'a> IntoIterator for &'a S { LL ~ type Item = &'a T; | ``` Move the previous long message to a note and use a shorter primary message: ``` error: missing lifetime in associated type --> $DIR/missing-lifetime-in-assoc-type-1.rs:9:17 | LL | impl<'a> IntoIterator for &S { | ---- there is a named lifetime specified on the impl block you could use ... LL | type Item = &T; | ^ this lifetime must come from the implemented type | note: in the trait the associated type is declared without lifetime parameters, so using a borrowed type for them requires that lifetime to come from the implemented type --> $SRC_DIR/core/src/iter/traits/collect.rs:LL:COL help: consider using the lifetime from the impl block | LL | type Item = &'a T; | ++ ``` r? ````@Nadrieril````
…saethlin Add -Zannotate-moves for profiler visibility of move/copy operations (codegen) **Note:** this is an alternative implementation of rust-lang#147206; rather than being a MIR transform, it adds the annotations closer to codegen. It's functionally the same but the implementation is lower impact and it could be more correct. --- This implements a new unstable compiler flag `-Zannotate-moves` that makes move and copy operations visible in profilers by creating synthetic debug information. This is achieved with zero runtime cost by manipulating debug info scopes to make moves/copies appear as calls to `compiler_move<T, SIZE>` and `compiler_copy<T, SIZE>` marker functions in profiling tools. This allows developers to identify expensive move/copy operations in their code using standard profiling tools, without requiring specialized tooling or runtime instrumentation. The implementation works at codegen time. When processing MIR operands (`Operand::Move` and `Operand::Copy`), the codegen creates an `OperandRef` with an optional `move_annotation` field containing an `Instance` of the appropriate profiling marker function. When storing the operand, `store_with_annotation()` wraps the store operation in a synthetic debug scope that makes it appear inlined from the marker. Two marker functions (`compiler_move` and `compiler_copy`) are defined in `library/core/src/profiling.rs`. These are never actually called - they exist solely as debug info anchors. Operations are only annotated if: - We're generating debug info and the feature is enabled. - Meets the size threshold (default: 65 bytes, configurable via `-Zannotate-moves=SIZE`), and is non-zero - Has a memory representation This has a very small size impact on object file size. With the default limit it's well under 0.1%, and even with a very small limit of 8 bytes it's still ~1.5%. This could be enabled by default.
…=saethlin Fix tests for big-endian The tests fail on s390x and presumably other big-endian systems, due to check of raw alloc values in the MIR output. To fix the tests remove the raw bytes from the MIR output (via: compile-flags: -Zdump-mir-exclude-alloc-bytes) and update the matching diffs.
compiler: Fix a couple issues around cargo feature unification cc rust-lang#148266. this doesn't fix all the issues (`rustc_public` and `rustc_transmute` still emit warnings when tested individually), but it fixes all the simple ones. To fix rustc_public I will probably need help from ```@AlexanderPortland``` or ```@makai410``` to make sure I am not accidentally cfg-ing out items that are meant to be public. To fix `rustc_transmute`, I will need to know (from ```@jswrenn``` ?) in what context the `rustc` cargo feature is disapled. To reproduce the issues, you can run `x test rustc_{transmute,public}` locally. --- The first issue I fixed was a warning in `rustc_index`: ``` Testing stage2 {rustc_parse_format} (aarch64-apple-darwin) Compiling rustc_index v0.0.0 (/Users/ci/project/compiler/rustc_index) error: extern crate `smallvec` is unused in crate `rustc_index` --> compiler/rustc_index/src/lib.rs:2:1 | 2 | #![cfg_attr(all(feature = "nightly", test), feature(stmt_expr_attributes))] | ^ | = help: remove the dependency or add `use smallvec as _;` to the crate root = note: `-D unused-crate-dependencies` implied by `-D warnings` = help: to override `-D warnings` add `#[allow(unused_crate_dependencies)]` error: could not compile `rustc_index` (lib) due to 1 previous error ``` The second was that `type_ir_macros` didn't fully specify its dependencies: ``` Testing stage1 {rustc_type_ir_macros} (aarch64-apple-darwin) Compiling rustc_type_ir_macros v0.0.0 (/Users/jyn/src/ferrocene3/compiler/rustc_type_ir_macros) error[E0432]: unresolved import `syn::visit_mut` --> compiler/rustc_type_ir_macros/src/lib.rs:2:10 | 2 | use syn::visit_mut::VisitMut; | ^^^^^^^^^ could not find `visit_mut` in `syn` | note: found an item that was configured out --> /Users/jyn/.local/lib/cargo/registry/src/index.crates.io-1949cf8c6b5b557f/syn-2.0.106/src/lib.rs:880:21 | 878 | #[cfg(feature = "visit-mut")] | --------------------- the item is gated behind the `visit-mut` feature 879 | #[cfg_attr(docsrs, doc(cfg(feature = "visit-mut")))] 880 | pub use crate::gen::visit_mut; | ^^^^^^^^^ error[E0433]: failed to resolve: could not find `visit_mut` in `syn` --> compiler/rustc_type_ir_macros/src/lib.rs:206:18 | 206 | syn::visit_mut::visit_type_path_mut(self, i); | ^^^^^^^^^ could not find `visit_mut` in `syn` | note: found an item that was configured out --> /Users/jyn/.local/lib/cargo/registry/src/index.crates.io-1949cf8c6b5b557f/syn-2.0.106/src/lib.rs:880:21 | 878 | #[cfg(feature = "visit-mut")] | --------------------- the item is gated behind the `visit-mut` feature 879 | #[cfg_attr(docsrs, doc(cfg(feature = "visit-mut")))] 880 | pub use crate::gen::visit_mut; | ^^^^^^^^^ ```
…uffix, r=fee1-dead
Dogfood `trim_{suffix|prefix}` in compiler
cc rust-lang#142312
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Nov 4, 2025
Rollup of 5 pull requests Successful merges: - #145314 (Tweak output of missing lifetime on associated type) - #147803 (Add -Zannotate-moves for profiler visibility of move/copy operations (codegen)) - #147925 (Fix tests for big-endian) - #148341 (compiler: Fix a couple issues around cargo feature unification) - #148371 (Dogfood `trim_{suffix|prefix}` in compiler) r? `@ghost` `@rustbot` modify labels: rollup
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Successful merges:
trim_{suffix|prefix}in compiler #148371 (Dogfoodtrim_{suffix|prefix}in compiler)r? @ghost
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