For some targets, rustc uses a "CRT fallback", where it links CRT
object files it ships instead of letting the host compiler link
them.
On musl, rustc currently links crt1, crti and crtn (provided by
libc), but does not link crtbegin and crtend (provided by libgcc).
In particular, crtend is responsible for terminating the .eh_frame
section. Lack of terminator may result in segfaults during
unwinding, as reported in #47551 and encountered by the LLVM 12
update in #81451.
This patch links crtbegin and crtend for musl as well, following
the table at the top of crt_objects.rs.
[librustdoc] Only split lang string on `,`, ` `, and `\t`
Split markdown lang strings into tokens on `,`.
The previous behavior was to split lang strings into tokens on any
character that wasn't a `_`, `_`, or alphanumeric.
This is a potentially breaking change, so please scrutinize! See discussion in #78344.
I noticed some test cases that made me wonder if there might have been some reason for the original behavior:
```
t("{.no_run .example}", false, true, Ignore::None, true, false, false, false, v(), None);
t("{.sh .should_panic}", true, false, Ignore::None, false, false, false, false, v(), None);
t("{.example .rust}", false, false, Ignore::None, true, false, false, false, v(), None);
t("{.test_harness .rust}", false, false, Ignore::None, true, true, false, false, v(), None);
```
It seemed pretty peculiar to specifically test lang strings in braces, with all the tokens prefixed by `.`.
I did some digging, and it looks like the test cases were added way back in [this commit from 2014](https://github.com/rust-lang/rust/commit/3fef7a74ca9a) by `@skade.`
It looks like they were added just to make sure that the splitting was permissive, and aren't testing that those strings in particular are accepted.
Closes https://github.com/rust-lang/rust/issues/78344.
This version adds the ability to use `rdpmc` hardware-based performance
counters instead of wall-clock time for measuring duration. This also
introduces a dependency on the `perf-event-open-sys` crate on Linux
which is used when using hardware counters.
Move pick_by_value_method docs above function header
- Currently style triggers #81183 so we can't add `#[instrument]` to
this function.
- Having docs above the header is more consistent with the rest of the
code base.
Cleanup `PpMode` and friends
This PR:
- Separates `PpSourceMode` and `PpHirMode` to remove invalid states
- Renames the variant to remove the redundant `Ppm` prefix
- Adds basic documentation for the different pretty-print modes
- Cleanups some code to make it more idiomatic
Not sure if this is actually useful, but it looks cleaner to me.
Add #[rustc_legacy_const_generics]
This is the first step towards removing `#[rustc_args_required_const]`: a new attribute is added which rewrites function calls of the form `func(a, b, c)` to `func::<{b}>(a, c)`. This allows previously stabilized functions in `stdarch` which use `rustc_args_required_const` to use const generics instead.
This new attribute is not intended to ever be stabilized, it is only intended for use in `stdarch` as a replacement for `#[rustc_args_required_const]`.
```rust
#[rustc_legacy_const_generics(1)]
pub fn foo<const Y: usize>(x: usize, z: usize) -> [usize; 3] {
[x, Y, z]
}
fn main() {
assert_eq!(foo(0 + 0, 1 + 1, 2 + 2), [0, 2, 4]);
assert_eq!(foo::<{1 + 1}>(0 + 0, 2 + 2), [0, 2, 4]);
}
```
r? `@oli-obk`
Improve error msgs when found type is deref of expected
This improves help messages in two cases:
- When expected type is `T` and found type is `&T`, we now look through blocks
and suggest dereferencing the expression of the block, rather than the whole
block.
- In the above case, if the expression is an `&`, we not suggest removing the
`&` instead of adding `*`.
Both of these are demonstrated in the regression test. Before this patch the
first error in the test would be:
error[E0308]: `if` and `else` have incompatible types
--> test.rs:8:9
|
5 | / if true {
6 | | a
| | - expected because of this
7 | | } else {
8 | | b
| | ^ expected `usize`, found `&usize`
9 | | };
| |_____- `if` and `else` have incompatible types
|
help: consider dereferencing the borrow
|
7 | } else *{
8 | b
9 | };
|
Now:
error[E0308]: `if` and `else` have incompatible types
--> test.rs:8:9
|
5 | / if true {
6 | | a
| | - expected because of this
7 | | } else {
8 | | b
| | ^
| | |
| | expected `usize`, found `&usize`
| | help: consider dereferencing the borrow: `*b`
9 | | };
| |_____- `if` and `else` have incompatible types
The second error:
error[E0308]: `if` and `else` have incompatible types
--> test.rs:14:9
|
11 | / if true {
12 | | 1
| | - expected because of this
13 | | } else {
14 | | &1
| | ^^ expected integer, found `&{integer}`
15 | | };
| |_____- `if` and `else` have incompatible types
|
help: consider dereferencing the borrow
|
13 | } else *{
14 | &1
15 | };
|
now:
error[E0308]: `if` and `else` have incompatible types
--> test.rs:14:9
|
11 | / if true {
12 | | 1
| | - expected because of this
13 | | } else {
14 | | &1
| | ^-
| | ||
| | |help: consider removing the `&`: `1`
| | expected integer, found `&{integer}`
15 | | };
| |_____- `if` and `else` have incompatible types
Fixes#82361
---
r? ````@estebank````
fix the false 'defined here' messages
Closes#80853.
Take this code:
```rust
struct S;
fn repro_ref(thing: S) {
thing();
}
```
Previously, the error message would be this:
```
error[E0618]: expected function, found `S`
--> src/lib.rs:4:5
|
3 | fn repro_ref(thing: S) {
| ----- `S` defined here
4 | thing();
| ^^^^^--
| |
| call expression requires function
error: aborting due to previous error
```
This is incorrect as `S` is not defined in the function arguments, `thing` is defined there. With this change, the following is emitted:
```
error[E0618]: expected function, found `S`
--> $DIR/80853.rs:4:5
|
LL | fn repro_ref(thing: S) {
| ----- is of type `S`
LL | thing();
| ^^^^^--
| |
| call expression requires function
|
= note: local variable `S` is not a function
error: aborting due to previous error
```
As you can see, this error message points out that `thing` is of type `S` and later in a note, that `S` is not a function. This change does seem like a downside for some error messages. Take this example:
```
LL | struct Empty2;
| -------------- is of type `Empty2`
```
As you can see, the error message shows that the definition of `Empty2` is of type `Empty2`. Although this isn't wrong, it would be more helpful if it would say something like this (which was there previously):
```
LL | struct Empty2;
| -------------- `Empty2` defined here
```
If there is a better way of doing this, where the `Empty2` example would stay the same as without this change, please inform me.
**Update: This is now fixed**
CC `@camelid`
Fix ICE caused by suggestion with no code substitutions
Change suggestion logic to filter and checking _before_ creating
specific resolution suggestion.
Assert earlier that suggestions contain code substitions to make it
easier in the future to debug invalid uses. If we find this becomes too
noisy in the wild, we can always make the emitter resilient to these
cases and remove the assertions.
Fix#78651.
- Currently style triggers #81183 so we can't add `#[instrument]` to
this function.
- Having docs above the header is more consistent with the rest of the
code base.
Make the `Query` enum a simple struct.
A lot of code in `rustc_query_system` is generic over it, only to encode an exceptional error case: query cycles.
The delayed computations are now done at cycle detection.
Refactor inlining decisions so that inexpensive criteria are considered first:
1. Based on code generation attributes.
2. Based on MIR availability (examines call graph).
3. Based on MIR body.
Consider auto derefs before warning about write only fields
Changes from #81473 extended the dead code lint with an ability to detect
fields that are written to but never read from. The implementation skips
over fields on the left hand side of an assignment, without marking them
as live.
A field access might involve an automatic dereference and de-facto read
the field. Conservatively mark expressions with deref adjustments as
live to avoid generating false positive warnings.
Closes#81626.
Implement -Z hir-stats for nested foreign items
An attempt to compute HIR stats for crates with nested foreign items results in an ICE.
```rust
fn main() {
extern "C" { fn f(); }
}
```
```
thread 'rustc' panicked at 'visit_nested_xxx must be manually implemented in this visitor'
```
Provide required implementation of visitor method.
Improve non_fmt_panic lint.
This change:
- fixes the span used by this lint in the case the panic argument is a single macro expansion (e.g. `panic!(a!())`);
- adds a suggestion for `panic!(format!(..))` to remove `format!()` instead of adding `"{}", ` or using `panic_any` like it does now; and
- fixes the incorrect suggestion to replace `panic![123]` by `panic_any(123]`.
Fixes#82109.
Fixes#82110.
Fixes#82111.
Example output:
```
warning: panic message is not a string literal
--> src/main.rs:8:12
|
8 | panic!(format!("error: {}", "oh no"));
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: `#[warn(non_fmt_panic)]` on by default
= note: this is no longer accepted in Rust 2021
= note: the panic!() macro supports formatting, so there's no need for the format!() macro here
help: remove the `format!(..)` macro call
|
8 | panic!("error: {}", "oh no");
| -- --
```
r? `@estebank`
Point out implicit deref coercions in borrow
Fixes#81365
`@Aaron1011` I'm not sure why my code shows the note even in an implicit `Deref` call. See the output for `issue-81365-8.rs`.
rustc_codegen_ssa: tune codegen according to available concurrency
This change tunes ahead-of-time codegening according to the amount of
concurrency available, rather than according to the number of CPUs on
the system. This can lower memory usage by reducing the number of
compiled LLVM modules in memory at once, particularly across several
rustc instances.
Previously, each rustc instance would assume that it should codegen
ahead of time to meet the demand of number-of-CPUs workers. But often, a
rustc instance doesn't have nearly that much concurrency available to
it, because the concurrency availability is split, via the jobserver,
across all active rustc instances spawned by the driving cargo process,
and is further limited by the `-j` flag argument. Therefore, each rustc
might have had several times the number of LLVM modules in memory than
it really needed to meet demand. If the modules were large, the effect
on memory usage would be noticeable.
With this change, the required amount of ahead-of-time codegen scales up
with the actual number of workers running within a rustc instance. Note
that the number of workers running can be less than the actual
concurrency available to a rustc instance. However, if more concurrency
is actually available, workers are spun up quickly as job tokens are
acquired, and the ahead-of-time codegen scales up quickly as well.
Set path of the compile unit to the source directory
As part of the effort to implement split dwarf debug info, we ended up
setting the compile unit location to the output directory rather than
the source directory. Furthermore, it seems like we failed to remap the
prefixes for this as well!
The desired behaviour is to instead set the `DW_AT_GNU_dwo_name` to a
path relative to compiler's working directory. This still allows
debuggers to find the split dwarf files, while not changing the
behaviour of the code that is compiling with regular debug info, and not
changing the compiler's behaviour with regards to reproducibility.
Fixes#82074
cc `@alexcrichton` `@davidtwco`
This improves help messages in two cases:
- When expected type is `T` and found type is `&T`, we now look through blocks
and suggest dereferencing the expression of the block, rather than the whole
block.
- In the above case, if the expression is an `&`, we not suggest removing the
`&` instead of adding `*`.
Both of these are demonstrated in the regression test. Before this patch the
first error in the test would be:
error[E0308]: `if` and `else` have incompatible types
--> test.rs:8:9
|
5 | / if true {
6 | | a
| | - expected because of this
7 | | } else {
8 | | b
| | ^ expected `usize`, found `&usize`
9 | | };
| |_____- `if` and `else` have incompatible types
|
help: consider dereferencing the borrow
|
7 | } else *{
8 | b
9 | };
|
Now:
error[E0308]: `if` and `else` have incompatible types
--> test.rs:8:9
|
5 | / if true {
6 | | a
| | - expected because of this
7 | | } else {
8 | | b
| | ^
| | |
| | expected `usize`, found `&usize`
| | help: consider dereferencing the borrow: `*b`
9 | | };
| |_____- `if` and `else` have incompatible types
The second error:
error[E0308]: `if` and `else` have incompatible types
--> test.rs:14:9
|
11 | / if true {
12 | | 1
| | - expected because of this
13 | | } else {
14 | | &1
| | ^^ expected integer, found `&{integer}`
15 | | };
| |_____- `if` and `else` have incompatible types
|
help: consider dereferencing the borrow
|
13 | } else *{
14 | &1
15 | };
|
now:
error[E0308]: `if` and `else` have incompatible types
--> test.rs:14:9
|
11 | / if true {
12 | | 1
| | - expected because of this
13 | | } else {
14 | | &1
| | ^-
| | ||
| | |help: consider removing the `&`: `1`
| | expected integer, found `&{integer}`
15 | | };
| |_____- `if` and `else` have incompatible types
Fixes#82361
Update the bootstrap compiler
This updates the bootstrap compiler, notably leaving out a change to enable semicolon in macro expressions lint, because stdarch still depends on the old behavior.
Make `treat_err_as_bug` Option<NonZeroUsize>
`rustc -Z treat-err-as-bug=N` already requires `N` to be nonzero when the argument is parsed, so changing the type from `Option<usize>` to `Option<NonZeroUsize>` is a low-hanging fruit in terms of layout optimization.
add s390x-unknown-linux-musl target
This is the first step in bringup for Rust on s390x.
The libc and std crates need modifications as well, but getting this upstream makes that work easier.
add diagnostic items for OsString/PathBuf/Owned as well as to_vec on slice
This is adding diagnostic items to be used by rust-lang/rust-clippy#6730, but my understanding is the clippy-side change does need to be done over there since I am adding a new clippy feature.
Add diagnostic items to the following types:
OsString (os_string_type)
PathBuf (path_buf_type)
Owned (to_owned_trait)
As well as the to_vec method on slice/[T]
Suggest `return`ing tail expressions that match return type
Some newcomers are confused by the behavior of tail expressions,
interpreting that "leaving out the `;` makes it the return value".
To help them go in the right direction, suggest using `return` instead
when applicable.
Improve suggestion for tuple struct pattern matching errors.
Closes#80174
This change allows numbers to be parsed as field names when pattern matching on structs, which allows us to provide better error messages when tuple structs are matched using a struct pattern.
r? ``@estebank``
Inline hot part of PatStack::head_ctor
When building rustc with `-Codegen-units=1` this inline hint ensures
that obtaining already initialized head constructor does not involve
a function call overhead and reduces the instruction count in
match-stress-enum-check full benchmark from 11.9G to 9.8G.
It shouldn't have significant impact on the currently default
configuration where it reflects existing inlining decisions.
MIR-OPT: Pass to deduplicate blocks
This pass finds basic blocks that are completely equal,
and replaces all uses with just one of them.
```bash
$ RUSTC_LOG=rustc_mir::transform::deduplicate_blocks ./x.py build --stage 2 | grep "SUCCESS: Replacing: " > log
...
$ cat log | wc -l
23875
```
Fix sizes of repr(C) enums on hexagon
Enums on hexagon use a smallest size (but at least 1 byte) that fits all
the enumeration values. This is unlike many other ABIs where enums are
at least 32 bits.
Fixes#82100
remove redundant option/result wrapping of return values
If a function always returns `Ok(something)`, we can return `something` directly and remove the corresponding error handling in the callers.
clippy::unnecessary_wraps
Make "missing field" error message more natural
```rust
struct A {
x: i32,
y: i32,
z: i32,
}
fn main() {
A { };
}
```
```
error[E0063]: missing fields `x`, `y`, `z` in initializer of `A`
--> src/main.rs:8:5
|
8 | A { };
| ^ missing `x`, `y`, `z`
```
This error is now:
```
error[E0063]: missing fields `x`, `y` and `z` in initializer of `A`
--> src/main.rs:8:5
|
8 | A { };
| ^ missing `x`, `y` and `z`
```
I thought it looked nicer and more natural this way. Also, if there is >3 fields missing, there is an "and" as well ("missing \`x\`, \`y\`, \`z\` *and* 1 other field"), but for <=3 there is not. As such it improves consistency too.
As for the implementation, originally I ended up with a chunky `push_str` algorithm but then I figured I could just do the formatting manually since it's just 3 field names at maximum. It is comparatively readable.
As a sidenote, one thing I was wondering about is, isn't there more cases where you have a list of things like field names? Maybe this whole thing can at some point later be made into a more general function to be used in multiple areas.
When a tail expression isn't unit, we previously always suggested adding
a trailing `;` to turn it into a statement. This suggestion isn't
appropriate for any expression that doesn't have side-effects, as the
user will have likely wanted to call something else or do something with
the resulting value, instead of just discarding it.
Some newcomers are confused by the behavior of tail expressions,
interpreting that "leaving out the `;` makes it the return value".
To help them go in the right direction, suggest using `return` instead
when applicable.
Enums on hexagon use a smallest size (but at least 1 byte) that fits all
the enumeration values. This is unlike many other ABIs where enums are
at least 32 bits.
Add new `rustc` target for Arm64 machines that can target the iphonesimulator
This PR lands a new target (`aarch64-apple-ios-sim`) that targets arm64 iphone simulator, previously unreachable from Apple Silicon machines.
resolves#81632
r? `@shepmaster`
LLVM picks the right things to put into the compiled object file based
on the target deployment version.
We need to communicate it through the target triple.
Only with that LLVM will use the right commands in the file to make it
look and behave like code compiled for the arm64 iOS simulator target.
Rollup of 7 pull requests
Successful merges:
- #80595 (`impl PartialEq<Punct> for char`; symmetry for #78636)
- #81991 (Fix panic in 'remove semicolon' when types are not local)
- #82176 (fix MIR fn-ptr pretty-printing)
- #82244 (Keep consistency in example for Stdin StdinLock)
- #82260 (rustc: Show ``@path`` usage in stable)
- #82316 (Fix minor mistake in LTO docs.)
- #82332 (Don't generate src link on dummy spans)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
fix MIR fn-ptr pretty-printing
An uninitialized function pointer would get printed as `{{uninit fn()}` (notice the unbalanced parentheses), and a dangling fn ptr would ICE. This fixes both of that.
However, I have no idea how to add tests for this.
Also, I don't understand this MIR pretty-printing code. Somehow the print function `pretty_print_const_scalar` actually *returns* a transformed form of the const (but there is no doc comment explaining what is being returned); some match arms do `p!` while others do `self =`, and there's a wild mixture of `p!` and `write!`... all very mysterious and confusing.^^
r? ``@oli-obk``
Fix panic in 'remove semicolon' when types are not local
It's not possible to check if removing a semicolon fixes the type error
when checking match arms and one or both of the last arm's and the
current arm's return types are imported "opaque" types. In these cases
we don't generate a "consider removing semicolon" suggestions.
Fixes#81839
---
I'm not sure how to add a test for this. I think the test would need at least two crates. Do we have any existing tests that do this so that I can take a look?
Move the query engine out of rustc_middle
The handling of queries is moved to a trait `QueryEngine`.
It replaces `query::Queries` in the `TyCtxt`, allowing to move the query engine out of librustc_middle.
There are 2 modes to access the query engine: through `TyCtxt` and dynamic dispatch,
or through a `QueryCtxt`. The `QueryCtxt` is required for everything touching the `OnDiskCache`.
For now, I put it in librustc_incremental, which is very small.
This may not be the best place.
A significant part of the codegen time for librustc_middle is moved to the recipient crate.
This PR may require a perf run.
cc #65031
r? `@Zoxc`
Make `Clean` take &mut DocContext
- Take `FnMut` in `rustc_trait_selection::find_auto_trait_generics`
- Take `&mut DocContext` in most of `clean`
- Collect the iterator in auto_trait_impls instead of iterating lazily; the lifetimes were really bad.
This combined with https://github.com/rust-lang/rust/pull/82018 should hopefully help with https://github.com/rust-lang/rust/pull/82014 by allowing `cx.cache.exported_traits` to be modified in `register_res`. Previously it had to use interior mutability, which required either adding a RefCell to `cache.exported_traits` on *top* of the existing `RefCell<Cache>` or mixing reads and writes between `cx.exported_traits` and `cx.cache.exported_traits`. I don't currently have that working but I expect it to be reasonably easy to add after this.
rustdoc: Support argument files
Factors out the `rustc_driver` logic that handles argument files so that rustdoc supports them as well, e.g.:
rustdoc `@argfile`
This is needed to be able to generate docs for projects that already use argument files when compiling them, e.g. projects that pass a huge number of `--cfg` arguments.
The feature was stabilized for `rustc` in #66172.
Do not ICE when evaluating locals' types of invalid `yield`
When a `yield` is outside of a generator, check its value regardless to
avoid an ICE while trying to get all locals' types in writeback.
Fix#78653.
ast: Keep expansion status for out-of-line module items
I.e. whether a module `mod foo;` is already loaded from a file or not.
This is a pre-requisite to correctly treating inner attributes on such modules (https://github.com/rust-lang/rust/issues/81661).
With this change AST structures for `mod` items diverge even more for AST structure for the crate root, which previously used `ast::Mod`.
Therefore this PR removes `ast::Mod` from `ast::Crate` in the first commit, these two things are sufficiently different from each other, at least at syntactic level.
Customization points for visiting a "`mod` item or crate root" were also removed from AST visitors (`fn visit_mod`).
`ast::Mod` itself was refactored away in the second commit in favor of `ItemKind::Mod(Unsafe, ModKind)`.
name async generators something more human friendly in type error diagnostic
fixes#81457
Some details:
1. I opted to load the generator kind from the hir in TyCategory. I also use 1 impl in the hir for the descr
2. I named both the source of the future, in addition to the general type (`future`), not sure what is preferred
3. I am not sure what is required to make sure "generator" is not referred to anywhere. A brief `rg "\"generator\"" showed me that most diagnostics correctly distinguish from generators and async generator, but the `descr` of `DefKind` is pretty general (not sure how thats used)
4. should the descr impl of AsyncGeneratorKind use its display impl instead of copying the string?
Factors out the `rustc_driver` logic that handles argument files
so that rustdoc supports them as well, e.g.:
rustdoc @argfile
This is needed to be able to generate docs for projects that
already use argument files when compiling them, e.g. projects
that pass a huge number of `--cfg` arguments.
The feature was stabilized for `rustc` in #66172.
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Changes from 81473 extended the dead code lint with an ability to detect
fields that are written to but never read from. The implementation skips
over fields on the left hand side of an assignment, without marking them
as live.
A field access might involve an automatic dereference and de-facto read
the field. Conservatively mark expressions with deref adjustments as
live to avoid generating false positive warnings.
Print -Ztime-passes (and misc stats/logs) on stderr, not stdout.
I've tried not to change anything that looked similar to `rustc --print`, where people might use automation, and/or any "bulk" prints, such as dumping an entire Graphviz (`dot`) graph on stdout.
The reason I want `-Ztime-passes` to be on stderr like debug logging is I can get a complete (and correctly interleaved) view just by looking at stderr, which is merely a convenience when running `rustc`/Cargo directly, but even more important when it's nested in a build script, as Cargo will split the build script output into stdout (named `output`) and `stderr`.
Optimize counting digits in line numbers during error reporting
Replaces `.to_string().len()` with simple loop and integer division, which avoids an unnecessary allocation.
Although I couldn't figure out how to directly profile `rustc`'s error reporting, I ran a microbenchmark on my machine (2.9 GHz Dual-Core Intel Core i5) on the two strategies for `0..100_000`, and the results seem promising:
```
test to_string_len ... bench: 12,124,792 ns/iter (+/- 700,652)
test while_loop ... bench: 30,333 ns/iter (+/- 562)
```
The x86_64 disassembly reduces integer division to a multiplication + shift, so I don't think there's any problems with using integer division.
For more (micro)optimization, it would be nice if we could avoid the initial check to see if the line number is nonzero, but I don't think `self.get_max_line_num(span, children)` _guarantees_ a nonzero line number.
Replace if-let and while-let with `if let` and `while let`
This pull request replaces if-let and while-let with `if let` and `while let`.
closes https://github.com/rust-lang/rust/issues/82205
const_generics: Dont evaluate array length const when handling yet another error
Same ICE as #82009 except triggered by a different error.
cc ``@lcnr``
r? ``@varkor``
Ensure valid TraitRefs are created for GATs
This fixes `ProjectionTy::trait_ref` to use the correct substs. Places that need all of the substs have been updated to not use `trait_ref`.
r? ````@jackh726````
It's not possible to check if removing a semicolon fixes the type error
when checking match arms and one or both of the last arm's and the
current arm's return types are imported "opaque" types. In these cases
we don't generate a "consider removing semicolon" suggestions.
Fixes#81839
Precompute ancestors when checking privacy
Precompute ancestors of the old error node set so that check for private
types and traits in public interfaces can in constant time determine if
the current item has any descendants in the old error set.
This removes disparity in compilation time between public and private type
aliases reported in #50614 (from 30 s to 5 s, in an example making extensive use
of private type aliases).
No functional changes intended.
Crate root is sufficiently different from `mod` items, at least at syntactic level.
Also remove customization point for "`mod` item or crate root" from AST visitors.
remove useless ?s (clippy::needless_question_marks)
Example code:
```rust
fn opts() -> Option<String> {
let s: Option<String> = Some(String::new());
Some(s?) // this can just be "s"
}
```
Use !Sync std::lazy::OnceCell in usefulness checking
The `rustc_data_structures::sync::OnceCell` is thread-safe when building
a parallel compiler. This is unnecessary for the purposes of pattern
usefulness checking. Use `!Sync` `std::lazy::OnceCell` instead.
Add diagnostics for specific cases for const/type mismatch err
For now, this adds at least more information so better diagnostics can be emitted for const mismatch errors.
I'm not sure what exactly we want to emit, so I've left notes there temporarily, also to see if this is the right approach
r? ```@lcnr```
cc: ```@estebank```
Implement RFC 2580: Pointer metadata & VTable
RFC: https://github.com/rust-lang/rfcs/pull/2580
~~Before merging this PR:~~
* [x] Wait for the end of the RFC’s [FCP to merge](https://github.com/rust-lang/rfcs/pull/2580#issuecomment-759145278).
* [x] Open a tracking issue: https://github.com/rust-lang/rust/issues/81513
* [x] Update `#[unstable]` attributes in the PR with the tracking issue number
----
This PR extends the language with a new lang item for the `Pointee` trait which is special-cased in trait resolution to implement it for all types. Even in generic contexts, parameters can be assumed to implement it without a corresponding bound.
For this I mostly imitated what the compiler was already doing for the `DiscriminantKind` trait. I’m very unfamiliar with compiler internals, so careful review is appreciated.
This PR also extends the standard library with new unstable APIs in `core::ptr` and `std::ptr`:
```rust
pub trait Pointee {
/// One of `()`, `usize`, or `DynMetadata<dyn SomeTrait>`
type Metadata: Copy + Send + Sync + Ord + Hash + Unpin;
}
pub trait Thin = Pointee<Metadata = ()>;
pub const fn metadata<T: ?Sized>(ptr: *const T) -> <T as Pointee>::Metadata {}
pub const fn from_raw_parts<T: ?Sized>(*const (), <T as Pointee>::Metadata) -> *const T {}
pub const fn from_raw_parts_mut<T: ?Sized>(*mut (),<T as Pointee>::Metadata) -> *mut T {}
impl<T: ?Sized> NonNull<T> {
pub const fn from_raw_parts(NonNull<()>, <T as Pointee>::Metadata) -> NonNull<T> {}
/// Convenience for `(ptr.cast(), metadata(ptr))`
pub const fn to_raw_parts(self) -> (NonNull<()>, <T as Pointee>::Metadata) {}
}
impl<T: ?Sized> *const T {
pub const fn to_raw_parts(self) -> (*const (), <T as Pointee>::Metadata) {}
}
impl<T: ?Sized> *mut T {
pub const fn to_raw_parts(self) -> (*mut (), <T as Pointee>::Metadata) {}
}
/// `<dyn SomeTrait as Pointee>::Metadata == DynMetadata<dyn SomeTrait>`
pub struct DynMetadata<Dyn: ?Sized> {
// Private pointer to vtable
}
impl<Dyn: ?Sized> DynMetadata<Dyn> {
pub fn size_of(self) -> usize {}
pub fn align_of(self) -> usize {}
pub fn layout(self) -> crate::alloc::Layout {}
}
unsafe impl<Dyn: ?Sized> Send for DynMetadata<Dyn> {}
unsafe impl<Dyn: ?Sized> Sync for DynMetadata<Dyn> {}
impl<Dyn: ?Sized> Debug for DynMetadata<Dyn> {}
impl<Dyn: ?Sized> Unpin for DynMetadata<Dyn> {}
impl<Dyn: ?Sized> Copy for DynMetadata<Dyn> {}
impl<Dyn: ?Sized> Clone for DynMetadata<Dyn> {}
impl<Dyn: ?Sized> Eq for DynMetadata<Dyn> {}
impl<Dyn: ?Sized> PartialEq for DynMetadata<Dyn> {}
impl<Dyn: ?Sized> Ord for DynMetadata<Dyn> {}
impl<Dyn: ?Sized> PartialOrd for DynMetadata<Dyn> {}
impl<Dyn: ?Sized> Hash for DynMetadata<Dyn> {}
```
API differences from the RFC, in areas noted as unresolved questions in the RFC:
* Module-level functions instead of associated `from_raw_parts` functions on `*const T` and `*mut T`, following the precedent of `null`, `slice_from_raw_parts`, etc.
* Added `to_raw_parts`
An attempt to compute HIR stats for crates with nested foreign items results in an ICE.
```
fn main() {
extern "C" { fn f(); }
}
```
```
thread 'rustc' panicked at 'visit_nested_xxx must be manually implemented in this visitor'
```
Provide required implementation of visitor method.
When building rustc with `-Codegen-units=1` this inline hint ensures
that obtaining already initialized head constructor does not involve
a function call overhead and reduces the instruction count in
match-stress-enum-check full benchmark from 11.9G to 9.8G.
It shouldn't have significant impact on the currently default
configuration where it reflects existing inlining decisions.
Implement reborrow for closure captures
The strategy for captures is detailed here with examples: https://hackmd.io/PzxYMPY4RF-B9iH9uj9GTA
Key points:
- We only need to reborrow a capture in case of move closures.
- If we mutate something via a `&mut` we store it as a `MutBorrow`/`UniqueMuBorrow` of the path containing the `&mut`,
- Similarly, if it's read via `&` ref we just store it as a `ImmBorrow` of the path containing the `&` ref.
- If a path doesn't deref a `&mut`, `&`, then that path is captured by Move.
- If the use of a path results in a move when the closure is called, then that path is truncated before any deref and the truncated path is moved into the closure.
- In the case of non-move closure if a use of a path results in a move, then the path is truncated before any deref and the truncated path is moved into the closure.
Note that the implementation differs a bit from the document to allow for truncated path to be used in the ClosureKind analysis that happens as part of the first capture analysis pass.
Closes: https://github.com/rust-lang/project-rfc-2229/issues/31
r? ````@nikomatsakis````
Placeholder lifetime error cleanup
- Remove note of trait definition
- Avoid repeating the same self type
- Use original region names when possible
- Use this error kind more often
- Print closure signatures when they are suppose to implement `Fn*` traits
Works towards #57374
r? ```@nikomatsakis```
Fix debug information for function arguments of type &str or slice.
Issue details:
When lowering MIR to LLVM IR, the compiler decomposes every &str and slice argument into a data pointer and a usize. Then, the original argument is reconstructed from the pointer and the usize arguments in the body of the function that owns it. Since the original argument is declared in the body of a function, it should be marked as a LocalVariable instead of an ArgumentVairable. This confusion causes MSVC debuggers unable to visualize &str and slice arguments correctly. (See https://github.com/rust-lang/rust/issues/81894 for more details).
Fix details:
Making sure that the debug variable for every &str and slice argument is marked as LocalVariable instead of ArgumentVariable in computing_per_local_var_debug_info. This change has been verified on VS Code debugger, VS debugger, WinDbg and LLDB.
Fix SourceMap::start_point
`start_point` needs to return the *first* character's span, but it would
previously call `find_width_of_character_at_span` which returns the span
of the *last* character. The implementation is now fixed.
Other changes:
- Docs for start_point, end_point, find_width_of_character_at_span
updated
- Minor simplification in find_width_of_character_at_span code
Fixes#81800
Don't fail to remove files if they are missing
In the backend we may want to remove certain temporary files, but in
certain other situations these files might not be produced in the first
place. We don't exactly care about that, and the intent is really that
these files are gone after a certain point in the backend.
Here we unify the backend file removing calls to use `ensure_removed`
which will attempt to delete a file, but will not fail if it does not
exist (anymore).
The tradeoff to this approach is, of course, that we may miss instances
were we are attempting to remove files at wrong paths due to some bug –
compilation would silently succeed but the temporary files would remain
there somewhere.
Add 'consider using' message to overflowing_literals
Fixes#79744.
Ironically, the `overflowing_literals` handler for binary or hex already
had this message! You would think it would be the other way around :)
cc ```@scottmcm```
- Take `FnMut` in `rustc_trait_selection::find_auto_trait_generics`
- Take `&mut DocContext` in most of `clean`
- Collect the iterator in auto_trait_impls instead of iterating lazily; the lifetimes were really bad.
- Changes `fn sess` to properly return a borrow with the lifetime of `'tcx`, not the mutable borrow.
Only store a LocalDefId in some HIR nodes
Some HIR nodes are guaranteed to be HIR owners: Item, TraitItem, ImplItem, ForeignItem and MacroDef.
As a consequence, we do not need to store the `HirId`'s `local_id`, and we can directly store a `LocalDefId`.
This allows to avoid a bit of the dance with `tcx.hir().local_def_id` and `tcx.hir().local_def_id_to_hir_id` mappings.
validation: fix invalid-fn-ptr error message
https://github.com/rust-lang/rust/pull/82061 changed the code here to print an `ImmTy` instead of a `ScalarMaybeUninit`; that was an accident. So go back to printing a `ScalarMaybeUninit`.
r? ```@oli-obk```
avoid full-slicing slices
If we already have a slice, there is no need to get another full-range slice from that, just use the original.
clippy::redundant_slicing
This change tunes ahead-of-time codegening according to the amount of
concurrency available, rather than according to the number of CPUs on
the system. This can lower memory usage by reducing the number of
compiled LLVM modules in memory at once, particularly across several
rustc instances.
Previously, each rustc instance would assume that it should codegen
ahead of time to meet the demand of number-of-CPUs workers. But often, a
rustc instance doesn't have nearly that much concurrency available to
it, because the concurrency availability is split, via the jobserver,
across all active rustc instances spawned by the driving cargo process,
and is further limited by the `-j` flag argument. Therefore, each rustc
might have had several times the number of LLVM modules in memory than
it really needed to meet demand. If the modules were large, the effect
on memory usage would be noticeable.
With this change, the required amount of ahead-of-time codegen scales up
with the actual number of workers running within a rustc instance. Note
that the number of workers running can be less than the actual
concurrency available to a rustc instance. However, if more concurrency
is actually available, workers are spun up quickly as job tokens are
acquired, and the ahead-of-time codegen scales up quickly as well.
