avoid promoting division, modulo and indexing operations that could fail #80579
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| @@ -8,21 +8,34 @@ | |||
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| #![warn(const_err, arithmetic_overflow, unconditional_panic)] | |||
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| // The only way to have promoteds that fail is in `const fn` called from `const`/`static`. | |||
| const fn overflow() -> u32 { | |||
| 0 - 1 | |||
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@oli-obk unlike in previous versions of this PR, the "arithmetic overflow" and "unconditional panic" lint does not fire here and in div_by_zero1 any more. Any idea why that is?
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Ah, I guess this is because we now have separate CTFE MIR, and do not run const-prop any more on the CTFE MIR. The fn is private and otherwise unused so regular MIR is never created.
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This was referenced Jan 24, 2021
JohnTitor
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to JohnTitor/rust
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Jan 29, 2021
clean up some const error reporting around promoteds These are some error reporting simplifications enabled by rust-lang#80579. Further simplifications are possible but could be blocked on making `const_err` a hard error. r? ``````@oli-obk``````
bjorn3
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Jan 30, 2021
clean up some const error reporting around promoteds These are some error reporting simplifications enabled by rust-lang/rust#80579. Further simplifications are possible but could be blocked on making `const_err` a hard error. r? ``````@oli-obk``````
bors
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Jan 31, 2021
…-obk codegen: assume constants cannot fail to evaluate rust-lang#80579 landed, so we can finally remove this old hack from codegen and instead assume that consts never fail to evaluate. :) r? `@oli-obk`
wip-sync
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to NetBSD/pkgsrc-wip
that referenced
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Apr 10, 2021
Pkgsrc changes:
* Remove one SunOS patch, apparently no longer needed.
* Adapt one patch for Darwin, adjust cargo checksum accordingly.
* Adjust bootstraps to version 1.50.0.
Version 1.51.0 (2021-03-25)
============================
Language
--------
- [You can now parameterize items such as functions, traits, and
`struct`s by constant values in addition to by types and
lifetimes.][79135] Also known as "const generics" E.g. you can
now write the following. Note: Only values of primitive integers,
`bool`, or `char` types are currently permitted.
```rust
struct GenericArray<T, const LENGTH: usize> {
inner: [T; LENGTH]
}
impl<T, const LENGTH: usize> GenericArray<T, LENGTH> {
const fn last(&self) -> Option<&T> {
if LENGTH == 0 {
None
} else {
Some(&self.inner[LENGTH - 1])
}
}
}
```
Compiler
--------
- [Added the `-Csplit-debuginfo` codegen option for macOS platforms.][79570]
This option controls whether debug information is split across
multiple files or packed into a single file. **Note** This option
is unstable on other platforms.
- [Added tier 3\* support for `aarch64_be-unknown-linux-gnu`,
`aarch64-unknown-linux-gnu_ilp32`, and
`aarch64_be-unknown-linux-gnu_ilp32` targets.][81455]
- [Added tier 3 support for `i386-unknown-linux-gnu` and
`i486-unknown-linux-gnu` targets.][80662]
- [The `target-cpu=native` option will now detect individual features
of CPUs.][80749]
- [Rust now uses `inline-asm` for stack probes when used with LLVM
11.0.1+][77885]
\* Refer to Rust's [platform support page][forge-platform-support]
for more information on Rust's tiered platform support.
Libraries
---------
- [`Box::downcast` is now also implemented for any `dyn Any + Send
+ Sync` object.][80945]
- [`str` now implements `AsMut<str>`.][80279]
- [`u64` and `u128` now implement `From<char>`.][79502]
- [`Error` is now implemented for `&T` where `T` implements `Error`.][75180]
- [`Poll::{map_ok, map_err}` are now implemented for `Poll<Option<Result<T,
E>>>`.][80968]
- [`unsigned_abs` is now implemented for all signed integer types.][80959]
- [`io::Empty` now implements `io::Seek`.][78044]
- [`rc::Weak<T>` and `sync::Weak<T>`'s methods such as `as_ptr`
are now implemented for `T: ?Sized` types.][80764]
Stabilized APIs
---------------
- [`Arc::decrement_strong_count`]
- [`Arc::increment_strong_count`]
- [`Once::call_once_force`]
- [`Peekable::next_if_eq`]
- [`Peekable::next_if`]
- [`Seek::stream_position`]
- [`array::IntoIter`]
- [`panic::panic_any`]
- [`ptr::addr_of!`]
- [`ptr::addr_of_mut!`]
- [`slice::fill_with`]
- [`slice::split_inclusive_mut`]
- [`slice::split_inclusive`]
- [`slice::strip_prefix`]
- [`slice::strip_suffix`]
- [`str::split_inclusive`]
- [`sync::OnceState`]
- [`task::Wake`]
Cargo
-----
- [Added the `split-debuginfo` profile option to control the -Csplit-debuginfo
codegen option.][cargo/9112]
- [Added the `resolver` field to `Cargo.toml` to enable the new
feature resolver and CLI option behavior.][cargo/8997] Version
2 of the feature resolver will try to avoid unifying features of
dependencies where that unification could be unwanted. Such as
using the same dependency with a `std` feature in a build scripts
and proc-macros, while using the `no-std` feature in the final
binary. See the [Cargo book documentation][[email protected]]
for more information on the feature.
Rustdoc
-------
- [Rustdoc will now include documentation for methods available
from `Deref` traits.][80653]
- [You can now provide a `--default-theme` flag which sets the
default theme to use for documentation.][79642]
Various improvements to intra-doc links:
- [You can link to non-path primitives such as `slice`.][80181]
- [You can link to associated items.][74489]
- [You can now include generic parameters when linking to items,
like `Vec<T>`.][76934]
Misc
----
- [You can now pass `--include-ignored` to tests (e.g. with
`cargo test -- --include-ignored`) to include testing tests marked
`#[ignore]`.][80053]
Compatibility Notes
-------------------
- [WASI platforms no longer use the `wasm-bindgen` ABI, and instead
use the wasm32 ABI.][79998]
- [`rustc` no longer promotes division, modulo and indexing operations
to `const` that could fail.][80579]
- [The minimum version of glibc for the following platforms has
been bumped to version 2.31 for the distributed artifacts.][81521]
- `armv5te-unknown-linux-gnueabi`
- `sparc64-unknown-linux-gnu`
- `thumbv7neon-unknown-linux-gnueabihf`
- `armv7-unknown-linux-gnueabi`
- `x86_64-unknown-linux-gnux32`
Internal Only
-------------
- [Consistently avoid constructing optimized MIR when not doing codegen][80718]
[79135]: rust-lang/rust#79135
[74489]: rust-lang/rust#74489
[76934]: rust-lang/rust#76934
[79570]: rust-lang/rust#79570
[80181]: rust-lang/rust#80181
[79642]: rust-lang/rust#79642
[80945]: rust-lang/rust#80945
[80279]: rust-lang/rust#80279
[80053]: rust-lang/rust#80053
[79502]: rust-lang/rust#79502
[75180]: rust-lang/rust#75180
[79135]: rust-lang/rust#79135
[81521]: rust-lang/rust#81521
[80968]: rust-lang/rust#80968
[80959]: rust-lang/rust#80959
[80718]: rust-lang/rust#80718
[80653]: rust-lang/rust#80653
[80579]: rust-lang/rust#80579
[79998]: rust-lang/rust#79998
[78044]: rust-lang/rust#78044
[81455]: rust-lang/rust#81455
[80764]: rust-lang/rust#80764
[80749]: rust-lang/rust#80749
[80662]: rust-lang/rust#80662
[77885]: rust-lang/rust#77885
[cargo/8997]: rust-lang/cargo#8997
[cargo/9112]: rust-lang/cargo#9112
[[email protected]]: https://doc.rust-lang.org/nightly/cargo/reference/features.html#feature-resolver-version-2
[`Once::call_once_force`]: https://doc.rust-lang.org/stable/std/sync/struct.Once.html#method.call_once_force
[`sync::OnceState`]: https://doc.rust-lang.org/stable/std/sync/struct.OnceState.html
[`panic::panic_any`]: https://doc.rust-lang.org/stable/std/panic/fn.panic_any.html
[`slice::strip_prefix`]: https://doc.rust-lang.org/stable/std/primitive.slice.html#method.strip_prefix
[`slice::strip_suffix`]: https://doc.rust-lang.org/stable/std/primitive.slice.html#method.strip_prefix
[`Arc::increment_strong_count`]: https://doc.rust-lang.org/nightly/std/sync/struct.Arc.html#method.increment_strong_count
[`Arc::decrement_strong_count`]: https://doc.rust-lang.org/nightly/std/sync/struct.Arc.html#method.decrement_strong_count
[`slice::fill_with`]: https://doc.rust-lang.org/nightly/std/primitive.slice.html#method.fill_with
[`ptr::addr_of!`]: https://doc.rust-lang.org/nightly/std/ptr/macro.addr_of.html
[`ptr::addr_of_mut!`]: https://doc.rust-lang.org/nightly/std/ptr/macro.addr_of_mut.html
[`array::IntoIter`]: https://doc.rust-lang.org/nightly/std/array/struct.IntoIter.html
[`slice::split_inclusive`]: https://doc.rust-lang.org/nightly/std/primitive.slice.html#method.split_inclusive
[`slice::split_inclusive_mut`]: https://doc.rust-lang.org/nightly/std/primitive.slice.html#method.split_inclusive_mut
[`str::split_inclusive`]: https://doc.rust-lang.org/nightly/std/primitive.str.html#method.split_inclusive
[`task::Wake`]: https://doc.rust-lang.org/nightly/std/task/trait.Wake.html
[`Seek::stream_position`]: https://doc.rust-lang.org/nightly/std/io/trait.Seek.html#method.stream_position
[`Peekable::next_if`]: https://doc.rust-lang.org/nightly/std/iter/struct.Peekable.html#method.next_if
[`Peekable::next_if_eq`]: https://doc.rust-lang.org/nightly/std/iter/struct.Peekable.html#method.next_if_eq
netbsd-srcmastr
pushed a commit
to NetBSD/pkgsrc
that referenced
this pull request
May 26, 2021
Pkgsrc changes:
* Add support for the big-endian arm64 NetBSD target (aarch64_be).
* On NetBSD/i386, use the i586 (pentium) bootstrap kit variant in
preference to i686.
* Adjust patches, re-compute line offsets, re-compute crate checksums.
* Remove a patch which was either integrated upstream and/or no longer
applies.
* Bump bootstraps to 1.50.0.
* Move conditionals until after bsd.prefs.mk so that they work...
* Default to "dist" build target if cross-compiling, but allow
also to override via rust.BUILD_TARGET.
* Allow overriding MAKE_JOBS_SAFE via rust.MAKE_JOBS_SAFE if you
want a different trade-off between occasional breakage and performance.
* Adjust platform.mk according to work already done in wip/rust/
* Add a patch to optimize the install.sh script used to install binary
bootstraps to not do so many forks; use case/esac and parameter expansion
instead of grep, sed and cut.
* Drop building documentation for the binary bootstrap kits. This will
also impact the lang/rust-bin package. For full documentation, build
or install lang/rust as a package.
Upstream changes:
Version 1.51.0 (2021-03-25)
============================
Language
--------
- [You can now parameterize items such as functions, traits, and
`struct`s by constant values in addition to by types and
lifetimes.][79135] Also known as "const generics" E.g. you can
now write the following. Note: Only values of primitive integers,
`bool`, or `char` types are currently permitted.
```rust
struct GenericArray<T, const LENGTH: usize> {
inner: [T; LENGTH]
}
impl<T, const LENGTH: usize> GenericArray<T, LENGTH> {
const fn last(&self) -> Option<&T> {
if LENGTH == 0 {
None
} else {
Some(&self.inner[LENGTH - 1])
}
}
}
```
Compiler
--------
- [Added the `-Csplit-debuginfo` codegen option for macOS platforms.][79570]
This option controls whether debug information is split across
multiple files or packed into a single file. **Note** This option
is unstable on other platforms.
- [Added tier 3\* support for `aarch64_be-unknown-linux-gnu`,
`aarch64-unknown-linux-gnu_ilp32`, and
`aarch64_be-unknown-linux-gnu_ilp32` targets.][81455]
- [Added tier 3 support for `i386-unknown-linux-gnu` and
`i486-unknown-linux-gnu` targets.][80662]
- [The `target-cpu=native` option will now detect individual features
of CPUs.][80749]
\* Refer to Rust's [platform support page][platform-support-doc] for more
information on Rust's tiered platform support.
Libraries
---------
- [`Box::downcast` is now also implemented for any `dyn Any + Send
+ Sync` object.][80945]
- [`str` now implements `AsMut<str>`.][80279]
- [`u64` and `u128` now implement `From<char>`.][79502]
- [`Error` is now implemented for `&T` where `T` implements `Error`.][75180]
- [`Poll::{map_ok, map_err}` are now implemented for
`Poll<Option<Result<T,E>>>`.][80968]
- [`unsigned_abs` is now implemented for all signed integer types.][80959]
- [`io::Empty` now implements `io::Seek`.][78044]
- [`rc::Weak<T>` and `sync::Weak<T>`'s methods such as `as_ptr`
are now implemented for `T: ?Sized` types.][80764]
- [`Div` and `Rem` by their `NonZero` variant is now implemented
for all unsigned integers.][79134]
Stabilized APIs
---------------
- [`Arc::decrement_strong_count`]
- [`Arc::increment_strong_count`]
- [`Once::call_once_force`]
- [`Peekable::next_if_eq`]
- [`Peekable::next_if`]
- [`Seek::stream_position`]
- [`array::IntoIter`]
- [`panic::panic_any`]
- [`ptr::addr_of!`]
- [`ptr::addr_of_mut!`]
- [`slice::fill_with`]
- [`slice::split_inclusive_mut`]
- [`slice::split_inclusive`]
- [`slice::strip_prefix`]
- [`slice::strip_suffix`]
- [`str::split_inclusive`]
- [`sync::OnceState`]
- [`task::Wake`]
- [`VecDeque::range`]
- [`VecDeque::range_mut`]
Cargo
-----
- [Added the `split-debuginfo` profile option to control the -Csplit-debuginfo
codegen option.][cargo/9112]
- [Added the `resolver` field to `Cargo.toml` to enable the new
feature resolver and CLI option behavior.][cargo/8997] Version
2 of the feature resolver will try to avoid unifying features of
dependencies where that unification could be unwanted. Such as
using the same dependency with a `std` feature in a build scripts
and proc-macros, while using the `no-std` feature in the final
binary. See the [Cargo book documentation][[email protected]]
for more information on the feature.
Rustdoc
-------
- [Rustdoc will now include documentation for methods available
from _nested_ `Deref` traits.][80653]
- [You can now provide a `--default-theme` flag which sets the
default theme to use for documentation.][79642]
Various improvements to intra-doc links:
- [You can link to non-path primitives such as `slice`.][80181]
- [You can link to associated items.][74489]
- [You can now include generic parameters when linking to items,
like `Vec<T>`.][76934]
Misc
----
- [You can now pass `--include-ignored` to tests (e.g. with
`cargo test -- --include-ignored`) to include testing tests marked
`#[ignore]`.][80053]
Compatibility Notes
-------------------
- [WASI platforms no longer use the `wasm-bindgen` ABI, and instead
use the wasm32 ABI.][79998]
- [`rustc` no longer promotes division, modulo and indexing operations
to `const` that could fail.][80579]
- [The minimum version of glibc for the following platforms has
been bumped to version 2.31 for the distributed artifacts.][81521]
- `armv5te-unknown-linux-gnueabi`
- `sparc64-unknown-linux-gnu`
- `thumbv7neon-unknown-linux-gnueabihf`
- `armv7-unknown-linux-gnueabi`
- `x86_64-unknown-linux-gnux32`
- [`atomic::spin_loop_hint` has been deprecated.][80966] It's
recommended to use `hint::spin_loop` instead.
Internal Only
-------------
- [Consistently avoid constructing optimized MIR when not doing codegen][80718]
[79135]: rust-lang/rust#79135
[74489]: rust-lang/rust#74489
[76934]: rust-lang/rust#76934
[79570]: rust-lang/rust#79570
[80181]: rust-lang/rust#80181
[79642]: rust-lang/rust#79642
[80945]: rust-lang/rust#80945
[80279]: rust-lang/rust#80279
[80053]: rust-lang/rust#80053
[79502]: rust-lang/rust#79502
[75180]: rust-lang/rust#75180
[79135]: rust-lang/rust#79135
[81521]: rust-lang/rust#81521
[80968]: rust-lang/rust#80968
[80959]: rust-lang/rust#80959
[80718]: rust-lang/rust#80718
[80653]: rust-lang/rust#80653
[80579]: rust-lang/rust#80579
[79998]: rust-lang/rust#79998
[78044]: rust-lang/rust#78044
[81455]: rust-lang/rust#81455
[80764]: rust-lang/rust#80764
[80749]: rust-lang/rust#80749
[80662]: rust-lang/rust#80662
[79134]: rust-lang/rust#79134
[80966]: rust-lang/rust#80966
[cargo/8997]: rust-lang/cargo#8997
[cargo/9112]: rust-lang/cargo#9112
[[email protected]]: https://doc.rust-lang.org/nightly/cargo/reference/features.html#feature-resolver-version-2
[`Once::call_once_force`]: https://doc.rust-lang.org/stable/std/sync/struct.Once.html#method.call_once_force
[`sync::OnceState`]: https://doc.rust-lang.org/stable/std/sync/struct.OnceState.html
[`panic::panic_any`]: https://doc.rust-lang.org/stable/std/panic/fn.panic_any.html
[`slice::strip_prefix`]: https://doc.rust-lang.org/stable/std/primitive.slice.html#method.strip_prefix
[`slice::strip_suffix`]: https://doc.rust-lang.org/stable/std/primitive.slice.html#method.strip_prefix
[`Arc::increment_strong_count`]: https://doc.rust-lang.org/nightly/std/sync/struct.Arc.html#method.increment_strong_count
[`Arc::decrement_strong_count`]: https://doc.rust-lang.org/nightly/std/sync/struct.Arc.html#method.decrement_strong_count
[`slice::fill_with`]: https://doc.rust-lang.org/nightly/std/primitive.slice.html#method.fill_with
[`ptr::addr_of!`]: https://doc.rust-lang.org/nightly/std/ptr/macro.addr_of.html
[`ptr::addr_of_mut!`]: https://doc.rust-lang.org/nightly/std/ptr/macro.addr_of_mut.html
[`array::IntoIter`]: https://doc.rust-lang.org/nightly/std/array/struct.IntoIter.html
[`slice::split_inclusive`]: https://doc.rust-lang.org/nightly/std/primitive.slice.html#method.split_inclusive
[`slice::split_inclusive_mut`]: https://doc.rust-lang.org/nightly/std/primitive.slice.html#method.split_inclusive_mut
[`str::split_inclusive`]: https://doc.rust-lang.org/nightly/std/primitive.str.html#method.split_inclusive
[`task::Wake`]: https://doc.rust-lang.org/nightly/std/task/trait.Wake.html
[`Seek::stream_position`]: https://doc.rust-lang.org/nightly/std/io/trait.Seek.html#method.stream_position
[`Peekable::next_if`]: https://doc.rust-lang.org/nightly/std/iter/struct.Peekable.html#method.next_if
[`Peekable::next_if_eq`]: https://doc.rust-lang.org/nightly/std/iter/struct.Peekable.html#method.next_if_eq
[`VecDeque::range`]: https://doc.rust-lang.org/nightly/std/collections/struct.VecDeque.html#method.range
[`VecDeque::range_mut`]: https://doc.rust-lang.org/nightly/std/collections/struct.VecDeque.html#method.range_mut
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For division,
x / ywill still be promoted ifyis a non-zero integer literal; however,1/(1+1)will not be promoted any more.While at it, also see if we can reject promoting floating-point arithmetic (which are complicated so maybe we should not promote them).
This will need a crater run to see if there's code out there that relies on these things being promoted.
If we can land this, promoteds in
fn/const fncannot fail to evaluate any more, which should let us do some simplifications in codegen/Miri!Cc rust-lang/rfcs#3027
Fixes #61821
r? @oli-obk