alloc: Add unstable Cfg feature `no-global_oom_handling
For certain sorts of systems, programming, it's deemed essential that
all allocation failures be explicitly handled where they occur. For
example, see Linus Torvald's opinion in [1]. Merely not calling global
panic handlers, or always `try_reserving` first (for vectors), is not
deemed good enough, because the mere presence of the global OOM handlers
is burdens static analysis.
One option for these projects to use rust would just be to skip `alloc`,
rolling their own allocation abstractions. But this would, in my
opinion be a real shame. `alloc` has a few `try_*` methods already, and
we could easily have more. Features like custom allocator support also
demonstrate and existing to support diverse use-cases with the same
abstractions.
A natural way to add such a feature flag would a Cargo feature, but
there are currently uncertainties around how std library crate's Cargo
features may or not be stable, so to avoid any risk of stabilizing by
mistake we are going with a more low-level "raw cfg" token, which
cannot be interacted with via Cargo alone.
Note also that since there is no notion of "default cfg tokens" outside
of Cargo features, we have to invert the condition from
`global_oom_handling` to to `not(no_global_oom_handling)`. This breaks
the monotonicity that would be important for a Cargo feature (i.e.
turning on more features should never break compatibility), but it
doesn't matter for raw cfg tokens which are not intended to be
"constraint solved" by Cargo or anything else.
To support this use-case we create a new feature, "global-oom-handling",
on by default, and put the global OOM handler infra and everything else
it that depends on it behind it. By default, nothing is changed, but
users concerned about global handling can make sure it is disabled, and
be confident that all OOM handling is local and explicit.
For this first iteration, non-flat collections are outright disabled.
`Vec` and `String` don't yet have `try_*` allocation methods, but are
kept anyways since they can be oom-safely created "from parts", and we
hope to add those `try_` methods in the future.
[1]: https://lore.kernel.org/lkml/CAHk-=wh_sNLoz84AUUzuqXEsYH35u=8HV3vK-jbRbJ_B-JjGrg@mail.gmail.com/
This commit implements both the native linking modifiers infrastructure
as well as an initial attempt at the individual modifiers from the RFC.
It also introduces a feature flag for the general syntax along with
individual feature flags for each modifier.
This defers backtrace formatting to the point where we
actually want to flush delayed diagnostics. If they are discarded
before that point then we can avoid invoking the backtrace formatting
machinery which will parse debug info and symbol tables.
for debuginfo=2 this leads to a 20% walltime reduction of the UI testsuite
For certain sorts of systems, programming, it's deemed essential that
all allocation failures be explicitly handled where they occur. For
example, see Linus Torvald's opinion in [1]. Merely not calling global
panic handlers, or always `try_reserving` first (for vectors), is not
deemed good enough, because the mere presence of the global OOM handlers
is burdens static analysis.
One option for these projects to use rust would just be to skip `alloc`,
rolling their own allocation abstractions. But this would, in my
opinion be a real shame. `alloc` has a few `try_*` methods already, and
we could easily have more. Features like custom allocator support also
demonstrate and existing to support diverse use-cases with the same
abstractions.
A natural way to add such a feature flag would a Cargo feature, but
there are currently uncertainties around how std library crate's Cargo
features may or not be stable, so to avoid any risk of stabilizing by
mistake we are going with a more low-level "raw cfg" token, which
cannot be interacted with via Cargo alone.
Note also that since there is no notion of "default cfg tokens" outside
of Cargo features, we have to invert the condition from
`global_oom_handling` to to `not(no_global_oom_handling)`. This breaks
the monotonicity that would be important for a Cargo feature (i.e.
turning on more features should never break compatibility), but it
doesn't matter for raw cfg tokens which are not intended to be
"constraint solved" by Cargo or anything else.
To support this use-case we create a new feature, "global-oom-handling",
on by default, and put the global OOM handler infra and everything else
it that depends on it behind it. By default, nothing is changed, but
users concerned about global handling can make sure it is disabled, and
be confident that all OOM handling is local and explicit.
For this first iteration, non-flat collections are outright disabled.
`Vec` and `String` don't yet have `try_*` allocation methods, but are
kept anyways since they can be oom-safely created "from parts", and we
hope to add those `try_` methods in the future.
[1]: https://lore.kernel.org/lkml/CAHk-=wh_sNLoz84AUUzuqXEsYH35u=8HV3vK-jbRbJ_B-JjGrg@mail.gmail.com/
Rollup of 11 pull requests
Successful merges:
- #83553 (Update `ptr` docs with regards to `ptr::addr_of!`)
- #84183 (Update RELEASES.md for 1.52.0)
- #84709 (Add doc alias for `chdir` to `std::env::set_current_dir`)
- #84803 (Reduce duplication in `impl_dep_tracking_hash` macros)
- #84808 (Account for unsatisfied bounds in E0599)
- #84843 (use else if in std library )
- #84865 (rustbuild: Pass a `threads` flag that works to windows-gnu lld)
- #84878 (Clarify documentation for `[T]::contains`)
- #84882 (platform-support: Center the contents of the `std` and `host` columns)
- #84903 (Remove `rustc_middle::mir::interpret::CheckInAllocMsg::NullPointerTest`)
- #84913 (Do not ICE on invalid const param)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Fix stack overflow issue in `redundant_pattern_matching`
Fixes#7169
~~cc `@Jarcho` Since tomorrow is release day and we need to get this also fixed in beta, I'll just revert the PR instead of looking into the root issue. Your changes are good, so if you have an idea what could cause this stack overflow and know how to fix it, please open a PR that reverts this revert with a fix.~~
r? `@llogiq`
changelog: none (fixes stack overflow, but this was introduced in this release cycle)
A metadata collection monster
This PR introduces a metadata collection lint as discussed in #4310. It currently collects:
* The lint ID
* The lint declaration file and location (for #1303)
* The lint group
* The documentation
* The applicability (if resolvable)
* If the suggestion is a multi-part-suggestion
This data has a slightly different structure than the current [lints.json](https://github.com/rust-lang/rust-clippy/blob/gh-pages/master/lints.json) and doesn't include depreciated lints yet. I plan to adapt the website to the new format and include depreciated lints in a follow-up PR :). The current collected json looks like this: [metadata_collection.json](https://gist.github.com/xFrednet/6b9e2c3f725f476ba88db9563f67e119)
The entire implementation is guarded behind the `metadata-collector-lint` feature and the `ENABLE_METADATA_COLLECTION` environment value to prevent default collection. You can test the implementation via:
```sh
$ ENABLE_METADATA_COLLECTION=1 cargo test --test dogfood --all-features
```
changelog: none
---
The size of this PR sadly also grew into a small monster, sorry! I definitely plan to improve on this! And it's totally okay if you take your time with this :)
r? `@phansch`
cc: `@flip1995`
Do not ICE on invalid const param
When encountering a path that can't have generics, do not call
`generics_of`. This would happen when writing something like
`path::this_is_a_mod<const_val>`.
Fix#84831.
Remove `rustc_middle::mir::interpret::CheckInAllocMsg::NullPointerTest`
Removing it per https://github.com/rust-lang/rust/pull/84842#discussion_r625589674: it's a dead enum variant.
Note that `PointerArithmeticTest` also seems dead:
```
$ rg -F PointerArithmeticTest -C5
compiler/rustc_middle/src/mir/interpret/error.rs
169-
170-/// Details of why a pointer had to be in-bounds.
171-#[derive(Debug, Copy, Clone, TyEncodable, TyDecodable, HashStable)]
172-pub enum CheckInAllocMsg {
173- MemoryAccessTest,
174: PointerArithmeticTest,
175- InboundsTest,
176-}
177-
178-impl fmt::Display for CheckInAllocMsg {
179- /// When this is printed as an error the context looks like this
--
182- write!(
183- f,
184- "{}",
185- match *self {
186- CheckInAllocMsg::MemoryAccessTest => "memory access",
187: CheckInAllocMsg::PointerArithmeticTest => "pointer arithmetic",
188- CheckInAllocMsg::InboundsTest => "inbounds test",
189- }
190- )
191- }
192-}
```
Not sure if that is also desirable to be removed, however.
Clarify documentation for `[T]::contains`
Change the documentation to correctly characterize when the suggested alternative to `contains` applies, and correctly explain why it works.
Fixes#84877
rustbuild: Pass a `threads` flag that works to windows-gnu lld
MinGW driver for COFF LLD doesn't currently translate GNU-style `--threads=N` to native `/threads:N`, so we have to pass the option in its native form to avoid an error.
Also pass the `threads` flag to lld-link (windows-msvc lld) as well.
Add doc alias for `chdir` to `std::env::set_current_dir`
Searching for `chdir` in the Rust documentation produces no useful
results.
I wrote some code recently that called `libc::chdir` and manually
handled errors, because I didn't realize that the safe
`std::env::set_current_dir` existed. I searched for `chdir` and
`change_dir` and `change_directory` (the latter two based on the
precedent of unabbreviating set by `create_dir`), and I also read
through `std::fs` expecting to potentially find it there. Given that
none of those led to `std::env::set_current_dir`, I think that provides
sufficient justification to add this specific alias.
Update `ptr` docs with regards to `ptr::addr_of!`
This updates the documentation since `ptr::addr_of!` and `ptr::addr_of_mut!` are now stable. One might remove the distinction between the sections `# On packed structs` and `# Examples`, as the old section on packed structs was primarily to prevent users of doing undefined behavior, which is not necessary anymore.
Technically there is now wrong/outdated documentation on stable, but I don't think this is worth a point release 😉Fixes#83509.
``````````@rustbot`````````` modify labels: T-doc
needless_collect: Lint cases with type annotations for indirect usage and recognize `BinaryHeap`
fixes#7110
changelog: needless_collect: Lint cases with type annotations for indirect usage and recognize `BinaryHeap`.
using allow_internal_unstable (as recommended)
Fixes: #84836
```shell
$ ./build/x86_64-unknown-linux-gnu/stage1/bin/rustc src/test/run-make-fulldeps/coverage/no_cov_crate.rs
error[E0554]: `#![feature]` may not be used on the dev release channel
--> src/test/run-make-fulldeps/coverage/no_cov_crate.rs:2:1
|
2 | #![feature(no_coverage)]
| ^^^^^^^^^^^^^^^^^^^^^^^^
error: aborting due to previous error
For more information about this error, try `rustc --explain E0554`.
```
