The previous setup did not properly consider hyperthreads (at least in local
testing), which likely skews CI results as well. The new code is both simpler
and hopefully will produce more accurate results.
Make rustc use `RUST_BACKTRACE=full` by default
Compiler panics should be rare - when they do occur, we want the report
filed by the user to contain as much information as possible. This is
especially important when the panic is due to an incremental compilation
bug, since we may not have enough information to reproduce it.
This PR sets `RUST_BACKTRACE=full` inside `rustc` if the user has not
explicitly set `RUST_BACKTRACE`. This is more verbose than
`RUST_BACKTRACE=1`, but this may make it easier to debug incremental
compilation issues. Users who find this too verbose can still manually
set `RUST_BACKTRACE` before invoking the compiler.
This only affects `rustc` (and any tool using `rustc_driver::install_ice_hook`).
It does *not* affect any user crates or the standard library -
backtraces will continue to be off by default in any application
*compiled* by rustc.
Temporary fix for the layout of aligned enums
Fix for the issue #92464
~~I was after this issue for quite some time now, I have a temporary fix for it.
I think the current problem is [here](e75f96763f/compiler/rustc_middle/src/ty/layout.rs (L1305-L1310)) created `tag` value might be wrong, because when I checked `min` and `max` values it's always between 0..1, which results in wrong size comparison in a few lines down below.
I think `min` and `max` values don't take `#[repr(aligned(8))]` into consideration and just act from base values assigned inside the enum. If what I am saying is true, aligned enums were created with the wrong layout for some time.~~
~~As stated in the title this is only a temporary fix and I think this needs further investigation, if someone wants to mentor it I would like to work on that too.~~ 😸
**Edit: Weird some tests fail now going to close this for now...**
**Edit2: I made it work again.**
I think I figured out the main problem of the issue, layout types of aligned enums with custom discriminant types were not handled, which resulted in confusing(such as this issue) behavior down the line, this is a kinda hacky fix for the issue.
pub use std::simd::StdFloat;
Syncs portable-simd up to commit rust-lang/portable-simd@03f6fbb21e,
Diff: 533f0fc81a...03f6fbb21e
This sync requires a little bit more legwork because it also introduces a trait into `std::simd`, so that it is no longer simply a reexport of `core::simd`. Out of simple-minded consistency and to allow more options, I replicated the pattern for the way `core::simd` is integrated in the first place, however this is not necessary if it doesn't acquire any interdependencies inside `std`: it could be a simple crate reexport. I just don't know yet if that will happen or not.
To summarize other misc changes:
- Shifts no longer panic, now wrap on too-large shifts (like `Simd` integers usually do!)
- mask16x32 will now be many i16s, not many i32s... 🙃
- `#[must_use]` is spread around generously
- Adjusts division, float min/max, and `Mask::{from,to}_array` internally to be faster
- Adds the much-requested `Simd::cast::<U>` function (equivalent to `simd.to_array().map(|lane| lane as U)`)
Compress amount of hashed bytes for `isize` values in StableHasher
This is another attempt to land https://github.com/rust-lang/rust/pull/92103, this time hopefully with a correct implementation w.r.t. stable hashing guarantees. The previous PR was [reverted](https://github.com/rust-lang/rust/pull/93014) because it could produce the [same hash](https://github.com/rust-lang/rust/pull/92103#issuecomment-1014625442) for different values even in quite simple situations. I have since added a basic [test](https://github.com/rust-lang/rust/pull/93193) that should guard against that situation, I also added a new test in this PR, specialised for this optimization.
## Why this optimization helps
Since the original PR, I have tried to analyze why this optimization even helps (and why it especially helps for `clap`). I found that the vast majority of stable-hashing `i64` actually comes from hashing `isize` (which is converted to `i64` in the stable hasher). I only found a single place where is this datatype used directly in the compiler, and this place has also been showing up in traces that I used to find out when is `isize` being hashed. This place is `rustc_span::FileName::DocTest`, however, I suppose that isizes also come from other places, but they might not be so easy to find (there were some other entries in the trace). `clap` hashes about 8.5 million `isize`s, and all of them fit into a single byte, which is why this optimization has helped it [quite a lot](https://github.com/rust-lang/rust/pull/92103#issuecomment-1005711861).
Now, I'm not sure if special casing `isize` is the correct solution here, maybe something could be done with that `isize` inside `DocTest` or in other places, but that's for another discussion I suppose. In this PR, instead of hardcoding a special case inside `SipHasher128`, I instead put it into `StableHasher`, and only used it for `isize` (I tested that for `i64` it doesn't help, or at least not for `clap` and other few benchmarks that I was testing).
## New approach
Since the most common case is a single byte, I added a fast path for hashing `isize` values which positive value fits within a single byte, and a cold path for the rest of the values.
To avoid the previous correctness problem, we need to make sure that each unique `isize` value will produce a unique hash stream to the hasher. By hash stream I mean a sequence of bytes that will be hashed (a different sequence should produce a different hash, but that is of course not guaranteed).
We have to distinguish different values that produce the same bit pattern when we combine them. For example, if we just simply skipped the leading zero bytes for values that fit within a single byte, `(0xFF, 0xFFFFFFFFFFFFFFFF)` and `(0xFFFFFFFFFFFFFFFF, 0xFF)` would send the same hash stream to the hasher, which must not happen.
To avoid this situation, values `[0, 0xFE]` are hashed as a single byte. When we hash a larger (treating `isize` as `u64`) value, we first hash an additional byte `0xFF`. Since `0xFF` cannot occur when we apply the single byte optimization, we guarantee that the hash streams will be unique when hashing two values `(a, b)` and `(b, a)` if `a != b`:
1) When both `a` and `b` are within `[0, 0xFE]`, their hash streams will be different.
2) When neither `a` and `b` are within `[0, 0xFE]`, their hash streams will be different.
3) When `a` is within `[0, 0xFE]` and `b` isn't, when we hash `(a, b)`, the hash stream will definitely not begin with `0xFF`. When we hash `(b, a)`, the hash stream will definitely begin with `0xFF`. Therefore the hash streams will be different.
r? `@the8472`
Support configuring whether to capture backtraces at runtime
Tracking issue: https://github.com/rust-lang/rust/issues/93346
This adds a new API to the `std::panic` module which configures whether and how the default panic hook will emit a backtrace when a panic occurs.
After discussion with `@yaahc` on [Zulip](https://rust-lang.zulipchat.com/#narrow/stream/219381-t-libs/topic/backtrace.20lib.20vs.2E.20panic), this PR chooses to avoid adjusting or seeking to provide a similar API for the (currently unstable) std::backtrace API. It seems likely that the users of that API may wish to expose more specific settings rather than just a global one (e.g., emulating the `env_logger`, `tracing` per-module configuration) to avoid the cost of capture in hot code. The API added here could plausibly be copied and/or re-exported directly from std::backtrace relatively easily, but I don't think that's the right call as of now.
```rust
mod panic {
#[derive(Copy, Clone, Debug, PartialEq, Eq)]
#[non_exhaustive]
pub enum BacktraceStyle {
Short,
Full,
Off,
}
fn set_backtrace_style(BacktraceStyle);
fn get_backtrace_style() -> Option<BacktraceStyle>;
}
```
Several unresolved questions:
* Do we need to move to a thread-local or otherwise more customizable strategy for whether to capture backtraces? See [this comment](https://github.com/rust-lang/rust/pull/79085#issuecomment-727845826) for some potential use cases for this.
* Proposed answer: no, leave this for third-party hooks.
* Bikeshed on naming of all the options, as usual.
* Should BacktraceStyle be moved into `std::backtrace`?
* It's already somewhat annoying to import and/or re-type the `std::panic::` prefix necessary to use these APIs, probably adding a second module to the mix isn't worth it.
Note that PR #79085 proposed a much simpler API, but particularly in light of the desire to fully replace setting environment variables via `env::set_var` to control the backtrace API, a more complete API seems preferable. This PR likely subsumes that one.
don't suggest adding `let` due to bad assignment expressions inside of `while` loop
adds a check that our `lhs` expression is actually within the conditional part of the `while` loop, instead of anywhere in the `while` body.
fixes#93486
[borrowck] Fix help on mutating &self in async fns
Previously, when rustc was provided an async function that tried to
mutate through a shared reference to an implicit self (as shown in the
ui test), rustc would suggest modifying the parameter signature
to `&mut` + the fully qualified name of the ty (in the case of the repro
`S`). If a user modified their code to match the suggestion, the
compiler would not accept it.
This commit modifies the suggestion so that when rustc is provided the
ui test that is also attached in this commit, it suggests (correctly)
`&mut self`. We try to be careful about distinguishing between implicit
and explicit self annotations, since the latter seem to be handled
correctly already.
This is my first PR here so I'm pretty sure I probably missed something/could use better terminology. I also didn't try to make the match exhaustive since implicit self is the only real special case that I need to handle (that I'm aware of), and I'm pretty sure there's a cleaner way to do this so any advice would be greatly appreciated! (I'm also not terribly confident about how I wrote the ui tests)
here is your cc as requested `@compiler-errors`
This is an attempt to fix#93093
debuginfo: Make sure that type names for closure and generator environments are unique in debuginfo.
Before this change, closure/generator environments coming from different instantiations of the same generic function were all assigned the same name even though they were distinct types with potentially different data layout. Now we append the generic arguments of the originating function to the type name.
This commit also emits `{closure_env#0}` as the name of these types in order to disambiguate them from the accompanying closure function (which keeps being called `{closure#0}`). Previously both were assigned the same name.
NOTE: Changing debuginfo names like this can break pretty printers and other debugger plugins. I think it's OK in this particular case because the names we are changing were ambiguous anyway. In general though it would be great to have a process for doing changes like these.
Compiler panics should be rare - when they do occur, we want the report
filed by the user to contain as much information as possible. This is
especially important when the panic is due to an incremental compilation
bug, since we may not have enough information to reproduce it.
This PR sets `RUST_BACKTRACE=full` inside `rustc` if the user has not
explicitly set `RUST_BACKTRACE`. This is more verbose than
`RUST_BACKTRACE=1`, but this may make it easier to debug incremental
compilation issues. Users who find this too verbose can still manually
set `RUST_BACKTRACE` before invoking the compiler.
This only affects `rustc` (and any tool using `rustc_driver::install_ice_hook`).
It does *not* affect any user crates or the standard library -
backtraces will continue to be off by default in any application
*compiled* by rustc.
Make dead code check a query.
Dead code check is run for each invocation of the compiler, even if no modifications were involved.
This PR makes dead code check a query keyed on the module. This allows to skip the check when a module has not changed.
To perform this, a query `live_symbols_and_ignored_derived_traits` is introduced to encapsulate the global analysis of finding live symbols. The second query `check_mod_deathness` outputs diagnostics for each module based on this first query's results.
Continue work on associated const equality
This actually implements some more complex logic for assigning associated consts to values.
Inside of projection candidates, it now defers to a separate function for either consts or
types. To reduce amount of code, projections are now generic over T, where T is either a Type or
a Const. I can add some comments back later, but this was the fastest way to implement it.
It also now finds the correct type of consts in type_of.
---
The current main TODO is finding the const of the def id for the LeafDef.
Right now it works if the function isn't called, but once you use the trait impl with the bound it fails inside projection.
I was hoping to get some help in getting the `&'tcx ty::Const<'tcx>`, in addition to a bunch of other `todo!()`s which I think may not be hit.
r? `@oli-obk`
Updates #92827
Enable combining `+crt-static` and `relocation-model=pic` on `x86_64-unknown-linux-gnu`
Modern `gcc` versions support `-static-pie`, and `rustc` will already fall-back to `-static` if the local `gcc` is too old (and hence this change is optimistic rather than absolute). This brings the `-musl` and `-gnu` targets to feature compatibility (albeit with different default settings).
Of note a `-static` or `-static-pie` binary based on glibc that uses NSS-backed functions (`gethostbyname` or `getpwuid` etc.) need to have access to the `libnss_X.so.2` libraries and any of their dynamic dependencies.
I wasn't sure about the `# only`/`# ignore` changes (I've not got a `gnux32` toolchain to test with hence not also enabling `-static-pie` there).
Disable drop range analysis
The previous PR, #93165, still performed the drop range analysis despite ignoring the results. Unfortunately, there were ICEs in the analysis as well, so some packages failed to build (see the issue #93197 for an example). This change further disables the analysis and just provides dummy results in that case.
Before this change, closure/generator environments coming from different
instantiations of the same generic function were all assigned the same
name even though they were distinct types with potentially different data
layout. Now we append the generic arguments of the originating function
to the type name.
This commit also emits '{closure_env#0}' as the name of these types in
order to disambiguate them from the accompanying closure function
'{closure#0}'. Previously both were assigned the same name.
Rollup of 9 pull requests
Successful merges:
- #91343 (Fix suggestion to slice if scrutinee is a `Result` or `Option`)
- #93019 (If an integer is entered with an upper-case base prefix (0Xbeef, 0O755, 0B1010), suggest to make it lowercase)
- #93090 (`impl Display for io::ErrorKind`)
- #93456 (Remove an unnecessary transmute from opaque::Encoder)
- #93492 (Hide failed command unless in verbose mode)
- #93504 (kmc-solid: Increase the default stack size)
- #93513 (Allow any pretty printed line to have at least 60 chars)
- #93532 (Update books)
- #93533 (Update cargo)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Update cargo
10 commits in 1c034752de0df744fcd7788fcbca158830b8bf85..25fcb135d02ea897ce894b67ae021f48107d522b
2022-01-25 22:36:53 +0000 to 2022-02-01 01:32:48 +0000
- fix(install): Keep v1 file formatting the same (rust-lang/cargo#10349)
- fix(vendor): Use tables for sample config (rust-lang/cargo#10348)
- Add bash completion for `cargo clippy` (rust-lang/cargo#10347)
- Do not ignore `--features` when `--all-features` is present (rust-lang/cargo#10337)
- test: Fix compatibilty with new toml_edit (rust-lang/cargo#10350)
- extra-link-arg-etc: support all link types (credit `@davidhewitt)` (rust-lang/cargo#10274)
- Make clippy happy (rust-lang/cargo#10340)
- Update publishing link for semver rules. (rust-lang/cargo#10338)
- Normalize --path when install bin outside current workspace (rust-lang/cargo#10335)
- Bump clap to v3.0.13 (rust-lang/cargo#10336)
Update books
## nomicon
4 commits in 66d097d3d80e8f88c288c6879c7c2b909ecf8ad4..9493715a6280a1f74be759c7e1ef9999b5d13e6f
2022-01-05 05:45:21 +0900 to 2022-01-27 19:00:32 -0800
- send-and-sync: it's -> its (rust-lang/nomicon#332)
- Clarify the HRTB chapter (rust-lang/nomicon#330)
- Clarify repr(transparent) in other-reprs (rust-lang/nomicon#329)
- Make C code more recognizably C (rust-lang/nomicon#331)
## reference
10 commits in 4dee6eb63d728ffb9e7a2ed443e9ada9275c69d2..411c2f0d5cebf48453ae2d136ad0c5e611d39aec
2022-01-18 09:26:33 -0800 to 2022-01-30 12:46:37 -0800
- paths.md: update comments of `Canoical paths` section (rust-lang/reference#1146)
- Add undocumented outer attributes above StructExpr fields (rust-lang/reference#1150)
- (rust-lang/reference#1148)
- Fix micro typo in async/unsafe function docs (rust-lang/reference#1145)
- Note difference in CTFE timing between associated and free constants (rust-lang/reference#1120)
- Update the Preludes chapter for the 2021 edition changes to the standard library prelude (rust-lang/reference#1136)
- Link to associated constants section rather than glossary (rust-lang/reference#1141)
- functions.md: replace `argument` with `parameter` (rust-lang/reference#1142)
- Improve rendering (rust-lang/reference#1143)
- (minor) link references and replace wording by syntax definition (rust-lang/reference#1139)
## book
24 commits in f17df27fc14696912c48b8b7a7a8fa49e648088d..98904efaa4fc968db8ff59cf2744d9f7ed158166
2022-01-18 17:46:28 -0500 to 2022-01-29 21:22:31 -0500
- Snapshot of chapter 17 for nostarch
- Remove the section on object safety.
- Don't put a hyphen in 'object safe'. Fixesrust-lang/book#2960.
- Clarify that add_text on Post will work in any state. Fixesrust-lang/book#2159.
- Fix incorrect descriptions of what the code is doing. Fixesrust-lang/book#2745.
- Fix link style and inclusion in print
- Snapshot of ch16 for nostarch
- Cut discussion of threading models Rust *doesn't* support.
- Update a quote of compiler output
- Move transfers between threads, not shares. Fixesrust-lang/book#2843.
- Ch20-02 Remove reference to a long-gone "trick"
- Clarify translations a bit
- Added a mention to the translations appendix
- Fix listing number from `8-5` to `9-5` in `ch09-02`
- Moving example into blockquote means it can't be extracted to a listing project
- Move a link to the end with all the other links
- Propagate edits back to ch 9
- Responding to edits in chapter 9
- Update to 1.58
- Snapshot of chapter 15 for nostarch
- Change 'only difference' to 'main difference'. Fixesrust-lang/book#1581.
- Add a back reference to tuple struct syntax. Fixesrust-lang/book#1916
- Add a link to a section reference
- Remove an outdated example that says it won't compile but it does
## rustc-dev-guide
2 commits in 78dd6a4684cf8d6b72275fab6d0429ea40b66338..8763adb62c712df69b1d39ea3e692b6d696cc4d9
2022-01-18 14:44:26 -0300 to 2022-01-26 14:01:40 -0800
- git.md: Expanded a note to try to stress what you need to do if you're playing
- Clarify that r? works in comments.
## embedded-book
1 commits in 8c395bdd8073deb20ca67e1ed4b14a3a7e315a37..d5fc1bce3f8eb398f9c25f1b15e0257d7537cd41
2021-11-14 11:38:31 +0000 to 2022-01-24 07:13:31 +0000
- Add link to Japanese translation (rust-embedded/book#311)
Allow any pretty printed line to have at least 60 chars
Follow-up to #93155. The rustc AST pretty printer has a tendency to get stuck in "vertical smear mode" when formatting highly nested code, where it puts a linebreak at *every possible* linebreak opportunity once the indentation goes beyond the pretty printer's target line width:
```rust
...
((&([("test"
as
&str)]
as
[&str; 1])
as
&[&str; 1]),
(&([]
as
[ArgumentV1; 0])
as
&[ArgumentV1; 0]))
...
```
```rust
...
[(1
as
i32),
(2
as
i32),
(3
as
i32)]
as
[i32; 3]
...
```
This is less common after #93155 because that PR greatly reduced the total amount of indentation, but the "vertical smear mode" failure mode is still just as present when you have deeply nested modules, functions, or trait impls, such as in the case of macro-expanded code from `-Zunpretty=expanded`.
Vertical smear mode is never the best way to format highly indented code though. It does not prevent the target line width from being exceeded, and it produces output that is less readable than just a longer line.
This PR makes the pretty printing algorithm allow a minimum of 60 chars on every line independent of indentation. So as code gets more indented, the right margin eventually recedes to make room for formatting without vertical smear.
```console
├─────────────────────────────────────┤
├─────────────────────────────────────┤
├─────────────────────────────────────┤
├───────────────────────────────────┤
├─────────────────────────────────┤
├───────────────────────────────┤
├─────────────────────────────┤
├───────────────────────────┤
├───────────────────────────┤
├───────────────────────────┤
├───────────────────────────┤
├───────────────────────────┤
├─────────────────────────────┤
├───────────────────────────────┤
├─────────────────────────────────┤
├───────────────────────────────────┤
├─────────────────────────────────────┤
```
Hide failed command unless in verbose mode
This is particularly intended for invoking compiletest; the command line there
is long (3,350 characters on my system) and takes up a lot of screen real estate
for little benefit to the majority of those running bootstrap. This moves
printing it to verbose mode (-v must be passed) which means that it's still
possible to access when needed for debugging.
The main downside is that CI logs will by-default become less usable for
debugging (particularly) spurious failures, but it is pretty rare for us to
really need the information there -- it's usually fairly obvious what is being
run with a little investigation.
r? `@ehuss` as you've done some of the spurious failure investigations, so can
(hopefully) confirm my intuition that this won't seriously hinder them.
If an integer is entered with an upper-case base prefix (0Xbeef, 0O755, 0B1010), suggest to make it lowercase
The current error for this case isn't really great, it just complains about the whole thing past the `0` being an invalid suffix.
