LLVM 18 x86 data layout update #116672

maurer · 2023-10-12T17:44:01Z

With https://reviews.llvm.org/D86310 LLVM now has i128 aligned to 16-bytes on x86 based platforms. This will be in LLVM-18. This patch updates all our spec targets to be 16-byte aligned, and removes the alignment when speaking to older LLVM.

This results in Rust overaligning things relative to LLVM on older LLVMs.

This implements MCP rust-lang/compiler-team#683.

See #54341

rustbot · 2023-10-12T17:44:11Z

r? @cjgillot

(rustbot has picked a reviewer for you, use r? to override)

rustbot · 2023-10-12T17:44:14Z

These commits modify compiler targets.
(See the Target Tier Policy.)

maurer · 2023-10-12T17:44:30Z

@rustbot label: +llvm-main

rustbot · 2023-10-12T17:55:38Z

These commits modify compiler targets.
(See the Target Tier Policy.)

cjgillot · 2023-10-12T18:18:09Z

r? @nikic

tgross35 · 2023-10-12T19:56:19Z

compiler/rustc_ast/src/ast.rs

+    #[cfg(not(bootstrap))]
+    static_assert_size!(LitKind, 32);
    static_assert_size!(Local, 72);
-    static_assert_size!(MetaItemLit, 40);
+    // This can be removed after i128:128 is in the bootstrap compiler's target.
+    #[cfg(not(bootstrap))]
+    static_assert_size!(MetaItemLit, 48);


I don't think config on bootstrap is too reliable since we could wind up with a bootstrap with either LLVM version. It would be better if there is a way to check the LLVM version here.

Alternatively, a static assertion that size can be either 24 or 32 (or 40/48) with a // FIXME: is probably suitable

This doesn't depend on the LLVM version - it depends on the alignment in the spec file. If you refer back to the zulip conversation we had, you'll note that TargetDataLayout will determine the size of these types, which is derived from the pre-munged data_layout, not the one after correction.

So in theory, after this rev, this should always be the case, regardless of LLVM version linked.

All that said, I might be misunderstanding something here, because I'm getting some creader issues in stage2+

Hm, then I guess those are coming from rustc using the new layout strings (16-byte align) while llvm <18 uses the adjusted version (8byte)? What happens if you update the layout strings, don't do the LLVM<18 fixup, and just suppress the "different default layout strings" error? I think that would force older LLVM to use 16byte alignment (like Clang does), which means all of rust upgrades at once.

I've just tested, and that works (./x.py test and ./x.py dist both complete locally).

The check still seemed valuable, so I've uploaded a change that makes the bug! conditional check the munged data layout rather than munging it when sending it to LLVM.

You can't do this, it will cause LLVM to assert. Even if LLVM didn't assert it would break cross-language LTO.

You seem to be right. I must have had asserts off locally or something, because this did work with the vendored LLVM locally.

Given that:

We can't adjust rustc's data layout without adjusting LLVM's data layout, that results in bugs.

We can't adjust LLVM's data layout on older LLVM.

Does that just leave the "newer LLVM needs to munge the data_layout early in execution, before TargetDataLayout gets built?

tgross35 · 2023-10-12T19:56:51Z

compiler/rustc_middle/src/mir/mod.rs

@@ -1585,13 +1585,19 @@ mod size_asserts {
    use super::*;
    use rustc_data_structures::static_assert_size;
    // tidy-alphabetical-start
-    static_assert_size!(BasicBlockData<'_>, 136);
+    // This can be removed after i128:128 is in the bootstrap compiler's target.
+    #[cfg(not(bootstrap))]


Same as the comment in compiler/rustc_ast/src/ast.rs

tmandry · 2023-10-12T22:09:59Z

Seems like this is worth mentioning in release notes. Possibly under compatibility notes?

@rustbot label relnotes

tgross35 · 2023-10-12T22:18:50Z

I was thinking this may be important enough to merit a blog post, so people know the change is coming and what to expect

Pack u128 in the compiler to mitigate new alignment This is based on rust-lang#116672, adding a new `#[repr(packed(8))]` wrapper on `u128` to avoid changing any of the compiler's size assertions. This is needed in two places: * `SwitchTargets`, otherwise its `SmallVec<[u128; 1]>` gets padded up to 32 bytes. * `LitKind::Int`, so that entire `enum` can stay 24 bytes. * This change definitely has far-reaching effects though, since it's public.

…cuviper Update data layouts in custom target tests for LLVM 18 Apply the data layout changes from rust-lang#116672 to custom target specs as well, as we started validating them since rust-lang#120062. Fixes rust-lang#120492. r? `@cuviper`

…cuviper Update data layouts in custom target tests for LLVM 18 Apply the data layout changes from rust-lang#116672 to custom target specs as well, as we started validating them since rust-lang#120062. Fixes rust-lang#120492. r? ``@cuviper``

…cuviper Update data layouts in custom target tests for LLVM 18 Apply the data layout changes from rust-lang#116672 to custom target specs as well, as we started validating them since rust-lang#120062. Fixes rust-lang#120492. r? ```@cuviper```

Rollup merge of rust-lang#120529 - nikic:llvm-18-datalayout-fixes, r=cuviper Update data layouts in custom target tests for LLVM 18 Apply the data layout changes from rust-lang#116672 to custom target specs as well, as we started validating them since rust-lang#120062. Fixes rust-lang#120492. r? ```@cuviper```

Related PRs so far: - rust-lang/rust#119869 - rust-lang/rust#120080 - rust-lang/rust#120128 - rust-lang/rust#119369 - rust-lang/rust#116672 By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 and MIT licenses. --------- Signed-off-by: Felipe R. Monteiro <felisous@amazon.com> Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com> Co-authored-by: tautschnig <tautschnig@users.noreply.github.com> Co-authored-by: Qinheping Hu <qinhh@amazon.com> Co-authored-by: Michael Tautschnig <tautschn@amazon.com> Co-authored-by: Felipe R. Monteiro <felisous@amazon.com>

The old CI test was removed (#77 (comment)) due to rust-lang/rust#116672 causing a mismatch of data layouts with the custom target (`src/tests/x86_64-soft_float.json`): ```console error: data-layout for target `x86_64-soft_float-10047705440633310713`, `e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128`, differs from LLVM target's `x86_64-unknown-none` default layout, `e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128` ``` This PR removes the unused custom target and reintroduces the CI test with the now-available tier 2 target [`x86_64-unknown-none`](https://doc.rust-lang.org/nightly/rustc/platfor m-support/x86_64-unknown-none.html). This makes this test much more robust, since we don't have to update a custom target ourselves and can even use stable Rust now. PR #146

Pkgsrc changes: * Adapt checksums and patches. Upstream chnages: Version 1.77.0 (2024-03-21) ========================== - [Reveal opaque types within the defining body for exhaustiveness checking.] (rust-lang/rust#116821) - [Stabilize C-string literals.] (rust-lang/rust#117472) - [Stabilize THIR unsafeck.] (rust-lang/rust#117673) - [Add lint `static_mut_refs` to warn on references to mutable statics.] (rust-lang/rust#117556) - [Support async recursive calls (as long as they have indirection).] (rust-lang/rust#117703) - [Undeprecate lint `unstable_features` and make use of it in the compiler.] (rust-lang/rust#118639) - [Make inductive cycles in coherence ambiguous always.] (rust-lang/rust#118649) - [Get rid of type-driven traversal in const-eval interning] (rust-lang/rust#119044), only as a [future compatiblity lint] (rust-lang/rust#122204) for now. - [Deny braced macro invocations in let-else.] (rust-lang/rust#119062) Compiler -------- - [Include lint `soft_unstable` in future breakage reports.] (rust-lang/rust#116274) - [Make `i128` and `u128` 16-byte aligned on x86-based targets.] (rust-lang/rust#116672) - [Use `--verbose` in diagnostic output.] (rust-lang/rust#119129) - [Improve spacing between printed tokens.] (rust-lang/rust#120227) - [Merge the `unused_tuple_struct_fields` lint into `dead_code`.] (rust-lang/rust#118297) - [Error on incorrect implied bounds in well-formedness check] (rust-lang/rust#118553), with a temporary exception for Bevy. - [Fix coverage instrumentation/reports for non-ASCII source code.] (rust-lang/rust#119033) - [Fix `fn`/`const` items implied bounds and well-formedness check.] (rust-lang/rust#120019) - [Promote `riscv32{im|imafc}-unknown-none-elf` targets to tier 2.] (rust-lang/rust#118704) - Add several new tier 3 targets: - [`aarch64-unknown-illumos`] (rust-lang/rust#112936) - [`hexagon-unknown-none-elf`] (rust-lang/rust#117601) - [`riscv32imafc-esp-espidf`] (rust-lang/rust#119738) - [`riscv32im-risc0-zkvm-elf`] (rust-lang/rust#117958) Refer to Rust's [platform support page][platform-support-doc] for more information on Rust's tiered platform support. Libraries --------- - [Implement `From<&[T; N]>` for `Cow<[T]>`.] (rust-lang/rust#113489) - [Remove special-case handling of `vec.split_off (0)`.](rust-lang/rust#119917) Stabilized APIs --------------- - [`array::each_ref`] (https://doc.rust-lang.org/stable/std/primitive.array.html#method.each_ref) - [`array::each_mut`] (https://doc.rust-lang.org/stable/std/primitive.array.html#method.each_mut) - [`core::net`] (https://doc.rust-lang.org/stable/core/net/index.html) - [`f32::round_ties_even`] (https://doc.rust-lang.org/stable/std/primitive.f32.html#method.round_ties_even) - [`f64::round_ties_even`] (https://doc.rust-lang.org/stable/std/primitive.f64.html#method.round_ties_even) - [`mem::offset_of!`] (https://doc.rust-lang.org/stable/std/mem/macro.offset_of.html) - [`slice::first_chunk`] (https://doc.rust-lang.org/stable/std/primitive.slice.html#method.first_chunk) - [`slice::first_chunk_mut`] (https://doc.rust-lang.org/stable/std/primitive.slice.html#method.first_chunk_mut) - [`slice::split_first_chunk`] (https://doc.rust-lang.org/stable/std/primitive.slice.html#method.split_first_chunk) - [`slice::split_first_chunk_mut`] (https://doc.rust-lang.org/stable/std/primitive.slice.html#method.split_first_chunk_mut) - [`slice::last_chunk`] (https://doc.rust-lang.org/stable/std/primitive.slice.html#method.last_chunk) - [`slice::last_chunk_mut`] (https://doc.rust-lang.org/stable/std/primitive.slice.html#method.last_chunk_mut) - [`slice::split_last_chunk`] (https://doc.rust-lang.org/stable/std/primitive.slice.html#method.split_last_chunk) - [`slice::split_last_chunk_mut`] (https://doc.rust-lang.org/stable/std/primitive.slice.html#method.split_last_chunk_mut) - [`slice::chunk_by`] (https://doc.rust-lang.org/stable/std/primitive.slice.html#method.chunk_by) - [`slice::chunk_by_mut`] (https://doc.rust-lang.org/stable/std/primitive.slice.html#method.chunk_by_mut) - [`Bound::map`] (https://doc.rust-lang.org/stable/std/ops/enum.Bound.html#method.map) - [`File::create_new`] (https://doc.rust-lang.org/stable/std/fs/struct.File.html#method.create_new) - [`Mutex::clear_poison`] (https://doc.rust-lang.org/stable/std/sync/struct.Mutex.html#method.clear_poison) - [`RwLock::clear_poison`] (https://doc.rust-lang.org/stable/std/sync/struct.RwLock.html#method.clear_poison) Cargo ----- - [Extend the build directive syntax with `cargo::`.] (rust-lang/cargo#12201) - [Stabilize metadata `id` format as `PackageIDSpec`.] (rust-lang/cargo#12914) - [Pull out as `cargo-util-schemas` as a crate.] (rust-lang/cargo#13178) - [Strip all debuginfo when debuginfo is not requested.] (rust-lang/cargo#13257) - [Inherit jobserver from env for all kinds of runners.] (rust-lang/cargo#12776) - [Deprecate rustc plugin support in cargo.] (rust-lang/cargo#13248) Rustdoc ----- - [Allows links in markdown headings.] (rust-lang/rust#117662) - [Search for tuples and unit by type with `()`.] (rust-lang/rust#118194) - [Clean up the source sidebar's hide button.] (rust-lang/rust#119066) - [Prevent JS injection from `localStorage`.] (rust-lang/rust#120250) Misc ---- - [Recommend version-sorting for all sorting in style guide.] (rust-lang/rust#115046) Internal Changes ---------------- These changes do not affect any public interfaces of Rust, but they represent significant improvements to the performance or internals of rustc and related tools. - [Add more weirdness to `weird-exprs.rs`.] (rust-lang/rust#119028)

Separate immediate and in-memory ScalarPair representation Currently, we assume that ScalarPair is always represented using a two-element struct, both as an immediate value and when stored in memory. This currently works fairly well, but runs into problems with rust-lang/rust#116672, where a ScalarPair involving an i128 type can no longer be represented as a two-element struct in memory. For example, the tuple `(i32, i128)` needs to be represented in-memory as `{ i32, [3 x i32], i128 }` to satisfy alignment requirements. Using `{ i32, i128 }` instead will result in the second element being stored at the wrong offset (prior to LLVM 18). Resolve this issue by no longer requiring that the immediate and in-memory type for ScalarPair are the same. The in-memory type will now look the same as for normal struct types (and will include padding filler and similar), while the immediate type stays a simple two-element struct type. This also means that booleans in immediate ScalarPair are now represented as i1 rather than i8, just like we do everywhere else. The core change here is to llvm_type (which now treats ScalarPair as a normal struct) and immediate_llvm_type (which returns the two-element struct that llvm_type used to produce). The rest is fixing things up to no longer assume these are the same. In particular, this switches places that try to get pointers to the ScalarPair elements to use byte-geps instead of struct-geps.

bjorn3 · 2024-10-04T13:18:40Z

tests/codegen/i128-x86-align.rs

+}
+
+#[no_mangle]
+pub fn load(x: &ScalarPair) -> ScalarPair {


Is it intentional that this is testing the rust abi? The C ABI returns ScalarPair quite differently using an sret pointer. #130899 will change the Rust ABI to also return it using an sret pointer.

I believe the intent was to test a case where i128 gets returned in an LLVM IR struct. If that situation no longer occurs after that PR, then testing the sret case is fine.

This is based on the pkgsrc-wip rust180 package, retaining the main pkgsrc changes as best as I could. Pkgsrc changes: * Adapt checksums and patches. * Make this work again on big-endian aarch64 (at least on NetBSD). * Make the choice of GCC = 12 work for sparc64 by testing options after options.mk is included (which is required...). Makes this work on NetBSD/sparc64 10.0 again. Upstream chnages: Version 1.80.1 (2024-08-08) =========================== - [Fix miscompilation in the jump threading MIR optimization when comparing floats] (rust-lang/rust#128271) - [Revert changes to the `dead_code` lint from 1.80.0] (rust-lang/rust#128618) Version 1.80.0 (2024-07-25) ========================== Language -------- - [Document maximum allocation size] (rust-lang/rust#116675) - [Allow zero-byte offsets and ZST read/writes on arbitrary pointers] (rust-lang/rust#117329) - [Support C23's variadics without a named parameter] (rust-lang/rust#124048) - [Stabilize `exclusive_range_pattern` feature] (rust-lang/rust#124459) - [Guarantee layout and ABI of `Result` in some scenarios] (rust-lang/rust#124870) Compiler -------- - [Update cc crate to v1.0.97 allowing additional spectre mitigations on MSVC targets] (rust-lang/rust#124892) - [Allow field reordering on types marked `repr(packed(1))`] (rust-lang/rust#125360) - [Add a lint against never type fallback affecting unsafe code] (rust-lang/rust#123939) - [Disallow cast with trailing braced macro in let-else] (rust-lang/rust#125049) - [Expand `for_loops_over_fallibles` lint to lint on fallibles behind references.] (rust-lang/rust#125156) - [self-contained linker: retry linking without `-fuse-ld=lld` on CCs that don't support it] (rust-lang/rust#125417) - [Do not parse CVarArgs (`...`) as a type in trait bounds] (rust-lang/rust#125863) - Improvements to LLDB formatting [#124458] (rust-lang/rust#124458) [#124500] (rust-lang/rust#124500) - [For the wasm32-wasip2 target default to PIC and do not use `-fuse-ld=lld`] (rust-lang/rust#124858) - [Add x86_64-unknown-linux-none as a tier 3 target] (rust-lang/rust#125023) - [Lint on `foo.into_iter()` resolving to `&Box<[T]>: IntoIterator`] (rust-lang/rust#124097) Libraries --------- - [Add `size_of` and `size_of_val` and `align_of` and `align_of_val` to the prelude] (rust-lang/rust#123168) - [Abort a process when FD ownership is violated] (rust-lang/rust#124210) - [io::Write::write_fmt: panic if the formatter fails when the stream does not fail] (rust-lang/rust#125012) - [Panic if `PathBuf::set_extension` would add a path separator] (rust-lang/rust#125070) - [Add assert_unsafe_precondition to unchecked_{add,sub,neg,mul,shl,shr} methods] (rust-lang/rust#121571) - [Update `c_char` on AIX to use the correct type] (rust-lang/rust#122986) - [`offset_of!` no longer returns a temporary] (rust-lang/rust#124484) - [Handle sigma in `str.to_lowercase` correctly] (rust-lang/rust#124773) - [Raise `DEFAULT_MIN_STACK_SIZE` to at least 64KiB] (rust-lang/rust#126059) Stabilized APIs --------------- - [`impl Default for Rc<CStr>`] (https://doc.rust-lang.org/beta/alloc/rc/struct.Rc.html#impl-Default-for-Rc%3CCStr%3E) - [`impl Default for Rc<str>`] (https://doc.rust-lang.org/beta/alloc/rc/struct.Rc.html#impl-Default-for-Rc%3Cstr%3E) - [`impl Default for Rc<[T]>`] (https://doc.rust-lang.org/beta/alloc/rc/struct.Rc.html#impl-Default-for-Rc%3C%5BT%5D%3E) - [`impl Default for Arc<str>`] (https://doc.rust-lang.org/beta/alloc/sync/struct.Arc.html#impl-Default-for-Arc%3Cstr%3E) - [`impl Default for Arc<CStr>`] (https://doc.rust-lang.org/beta/alloc/sync/struct.Arc.html#impl-Default-for-Arc%3CCStr%3E) - [`impl Default for Arc<[T]>`] (https://doc.rust-lang.org/beta/alloc/sync/struct.Arc.html#impl-Default-for-Arc%3C%5BT%5D%3E) - [`impl IntoIterator for Box<[T]>`] (https://doc.rust-lang.org/beta/alloc/boxed/struct.Box.html#impl-IntoIterator-for-Box%3C%5BI%5D,+A%3E) - [`impl FromIterator<String> for Box<str>`] (https://doc.rust-lang.org/beta/alloc/boxed/struct.Box.html#impl-FromIterator%3CString%3E-for-Box%3Cstr%3E) - [`impl FromIterator<char> for Box<str>`] (https://doc.rust-lang.org/beta/alloc/boxed/struct.Box.html#impl-FromIterator%3Cchar%3E-for-Box%3Cstr%3E) - [`LazyCell`] (https://doc.rust-lang.org/beta/core/cell/struct.LazyCell.html) - [`LazyLock`] (https://doc.rust-lang.org/beta/std/sync/struct.LazyLock.html) - [`Duration::div_duration_f32`] (https://doc.rust-lang.org/beta/std/time/struct.Duration.html#method.div_duration_f32) - [`Duration::div_duration_f64`] (https://doc.rust-lang.org/beta/std/time/struct.Duration.html#method.div_duration_f64) - [`Option::take_if`] (https://doc.rust-lang.org/beta/std/option/enum.Option.html#method.take_if) - [`Seek::seek_relative`] (https://doc.rust-lang.org/beta/std/io/trait.Seek.html#method.seek_relative) - [`BinaryHeap::as_slice`] (https://doc.rust-lang.org/beta/std/collections/struct.BinaryHeap.html#method.as_slice) - [`NonNull::offset`] (https://doc.rust-lang.org/beta/std/ptr/struct.NonNull.html#method.offset) - [`NonNull::byte_offset`] (https://doc.rust-lang.org/beta/std/ptr/struct.NonNull.html#method.byte_offset) - [`NonNull::add`] (https://doc.rust-lang.org/beta/std/ptr/struct.NonNull.html#method.add) - [`NonNull::byte_add`] (https://doc.rust-lang.org/beta/std/ptr/struct.NonNull.html#method.byte_add) - [`NonNull::sub`] (https://doc.rust-lang.org/beta/std/ptr/struct.NonNull.html#method.sub) - [`NonNull::byte_sub`] (https://doc.rust-lang.org/beta/std/ptr/struct.NonNull.html#method.byte_sub) - [`NonNull::offset_from`] (https://doc.rust-lang.org/beta/std/ptr/struct.NonNull.html#method.offset_from) - [`NonNull::byte_offset_from`] (https://doc.rust-lang.org/beta/std/ptr/struct.NonNull.html#method.byte_offset_from) - [`NonNull::read`] (https://doc.rust-lang.org/beta/std/ptr/struct.NonNull.html#method.read) - [`NonNull::read_volatile`] (https://doc.rust-lang.org/beta/std/ptr/struct.NonNull.html#method.read_volatile) - [`NonNull::read_unaligned`] (https://doc.rust-lang.org/beta/std/ptr/struct.NonNull.html#method.read_unaligned) - [`NonNull::write`] (https://doc.rust-lang.org/beta/std/ptr/struct.NonNull.html#method.write) - [`NonNull::write_volatile`] (https://doc.rust-lang.org/beta/std/ptr/struct.NonNull.html#method.write_volatile) - [`NonNull::write_unaligned`] (https://doc.rust-lang.org/beta/std/ptr/struct.NonNull.html#method.write_unaligned) - [`NonNull::write_bytes`] (https://doc.rust-lang.org/beta/std/ptr/struct.NonNull.html#method.write_bytes) - [`NonNull::copy_to`] (https://doc.rust-lang.org/beta/std/ptr/struct.NonNull.html#method.copy_to) - [`NonNull::copy_to_nonoverlapping`] (https://doc.rust-lang.org/beta/std/ptr/struct.NonNull.html#method.copy_to_nonoverlapping) - [`NonNull::copy_from`] (https://doc.rust-lang.org/beta/std/ptr/struct.NonNull.html#method.copy_from) - [`NonNull::copy_from_nonoverlapping`] (https://doc.rust-lang.org/beta/std/ptr/struct.NonNull.html#method.copy_from_nonoverlapping) - [`NonNull::replace`] (https://doc.rust-lang.org/beta/std/ptr/struct.NonNull.html#method.replace) - [`NonNull::swap`] (https://doc.rust-lang.org/beta/std/ptr/struct.NonNull.html#method.swap) - [`NonNull::drop_in_place`] (https://doc.rust-lang.org/beta/std/ptr/struct.NonNull.html#method.drop_in_place) - [`NonNull::align_offset`] (https://doc.rust-lang.org/beta/std/ptr/struct.NonNull.html#method.align_offset) - [`<[T]>::split_at_checked`] (https://doc.rust-lang.org/beta/std/primitive.slice.html#method.split_at_checked) - [`<[T]>::split_at_mut_checked`] (https://doc.rust-lang.org/beta/std/primitive.slice.html#method.split_at_mut_checked) - [`str::split_at_checked`] (https://doc.rust-lang.org/beta/std/primitive.str.html#method.split_at_checked) - [`str::split_at_mut_checked`] (https://doc.rust-lang.org/beta/std/primitive.str.html#method.split_at_mut_checked) - [`str::trim_ascii`] (https://doc.rust-lang.org/beta/std/primitive.str.html#method.trim_ascii) - [`str::trim_ascii_start`] (https://doc.rust-lang.org/beta/std/primitive.str.html#method.trim_ascii_start) - [`str::trim_ascii_end`] (https://doc.rust-lang.org/beta/std/primitive.str.html#method.trim_ascii_end) - [`<[u8]>::trim_ascii`] (https://doc.rust-lang.org/beta/core/primitive.slice.html#method.trim_ascii) - [`<[u8]>::trim_ascii_start`] (https://doc.rust-lang.org/beta/core/primitive.slice.html#method.trim_ascii_start) - [`<[u8]>::trim_ascii_end`] (https://doc.rust-lang.org/beta/core/primitive.slice.html#method.trim_ascii_end) - [`Ipv4Addr::BITS`] (https://doc.rust-lang.org/beta/core/net/struct.Ipv4Addr.html#associatedconstant.BITS) - [`Ipv4Addr::to_bits`] (https://doc.rust-lang.org/beta/core/net/struct.Ipv4Addr.html#method.to_bits) - [`Ipv4Addr::from_bits`] (https://doc.rust-lang.org/beta/core/net/struct.Ipv4Addr.html#method.from_bits) - [`Ipv6Addr::BITS`] (https://doc.rust-lang.org/beta/core/net/struct.Ipv6Addr.html#associatedconstant.BITS) - [`Ipv6Addr::to_bits`] (https://doc.rust-lang.org/beta/core/net/struct.Ipv6Addr.html#method.to_bits) - [`Ipv6Addr::from_bits`] (https://doc.rust-lang.org/beta/core/net/struct.Ipv6Addr.html#method.from_bits) - [`Vec::<[T; N]>::into_flattened`] (https://doc.rust-lang.org/beta/alloc/vec/struct.Vec.html#method.into_flattened) - [`<[[T; N]]>::as_flattened`] (https://doc.rust-lang.org/beta/core/primitive.slice.html#method.as_flattened) - [`<[[T; N]]>::as_flattened_mut`] (https://doc.rust-lang.org/beta/core/primitive.slice.html#method.as_flattened_mut) These APIs are now stable in const contexts: - [`<[T]>::last_chunk`] (https://doc.rust-lang.org/beta/core/primitive.slice.html#method.last_chunk) - [`BinaryHeap::new`] (https://doc.rust-lang.org/beta/std/collections/struct.BinaryHeap.html#method.new) Cargo ----- - [Stabilize `-Zcheck-cfg` as always enabled] (rust-lang/cargo#13571) - [Warn, rather than fail publish, if a target is excluded] (rust-lang/cargo#13713) - [Add special `check-cfg` lint config for the `unexpected_cfgs` lint] (rust-lang/cargo#13913) - [Stabilize `cargo update --precise <yanked>`] (rust-lang/cargo#13974) - [Don't change file permissions on `Cargo.toml` when using `cargo add`] (rust-lang/cargo#13898) - [Support using `cargo fix` on IPv6-only networks] (rust-lang/cargo#13907) Rustdoc ----- - [Allow searching for references] (rust-lang/rust#124148) - [Stabilize `custom_code_classes_in_docs` feature] (rust-lang/rust#124577) - [fix: In cross-crate scenarios show enum variants on type aliases of enums] (rust-lang/rust#125300) Compatibility Notes ------------------- - [rustfmt estimates line lengths differently when using non-ascii characters] (rust-lang/rustfmt#6203) - [Type aliases are now handled correctly in orphan check] (rust-lang/rust#117164) - [Allow instructing rustdoc to read from stdin via `-`] (rust-lang/rust#124611) - [`std::env::{set_var, remove_var}` can no longer be converted to safe function pointers and no longer implement the `Fn` family of traits] (rust-lang/rust#124636) - [Warn (or error) when `Self` constructor from outer item is referenced in inner nested item] (rust-lang/rust#124187) - [Turn `indirect_structural_match` and `pointer_structural_match` lints into hard errors] (rust-lang/rust#124661) - [Make `where_clause_object_safety` lint a regular object safety violation] (rust-lang/rust#125380) - [Turn `proc_macro_back_compat` lint into a hard error.] (rust-lang/rust#125596) - [Detect unused structs even when implementing private traits] (rust-lang/rust#122382) - [`std::sync::ReentrantLockGuard<T>` is no longer `Sync` if `T: !Sync`] (rust-lang/rust#125527) which means [`std::io::StdoutLock` and `std::io::StderrLock` are no longer Sync] (rust-lang/rust#127340) Internal Changes ---------------- These changes do not affect any public interfaces of Rust, but they represent significant improvements to the performance or internals of rustc and related tools. - Misc improvements to size of generated html by rustdoc e.g. [#124738] (rust-lang/rust#124738) and [#123734] (rust-lang/rust#123734) - [MSVC targets no longer depend on libc] (rust-lang/rust#124050) Version 1.79.0 (2024-06-13) ========================== Language -------- - [Stabilize inline `const {}` expressions.] (rust-lang/rust#104087) - [Prevent opaque types being instantiated twice with different regions within the same function.] (rust-lang/rust#116935) - [Stabilize WebAssembly target features that are in phase 4 and 5.] (rust-lang/rust#117457) - [Add the `redundant_lifetimes` lint to detect lifetimes which are semantically redundant.] (rust-lang/rust#118391) - [Stabilize the `unnameable_types` lint for public types that can't be named.] (rust-lang/rust#120144) - [Enable debuginfo in macros, and stabilize `-C collapse-macro-debuginfo` and `#[collapse_debuginfo]`.] (rust-lang/rust#120845) - [Propagate temporary lifetime extension into `if` and `match` expressions.] (rust-lang/rust#121346) - [Restrict promotion of `const fn` calls.] (rust-lang/rust#121557) - [Warn against refining impls of crate-private traits with `refining_impl_trait` lint.] (rust-lang/rust#121720) - [Stabilize associated type bounds (RFC 2289).] (rust-lang/rust#122055) - [Stabilize importing `main` from other modules or crates.] (rust-lang/rust#122060) - [Check return types of function types for well-formedness] (rust-lang/rust#115538) - [Rework `impl Trait` lifetime inference] (rust-lang/rust#116891) - [Change inductive trait solver cycles to be ambiguous] (rust-lang/rust#122791) Compiler -------- - [Define `-C strip` to only affect binaries, not artifacts like `.pdb`.] (rust-lang/rust#115120) - [Stabilize `-Crelro-level` for controlling runtime link hardening.] (rust-lang/rust#121694) - [Stabilize checking of `cfg` names and values at compile-time with `--check-cfg`.] (rust-lang/rust#123501) *Note that this only stabilizes the compiler part, the Cargo part is still unstable in this release.* - [Add `aarch64-apple-visionos` and `aarch64-apple-visionos-sim` tier 3 targets.] (rust-lang/rust#121419) - [Add `riscv32ima-unknown-none-elf` tier 3 target.] (rust-lang/rust#122696) - [Promote several Windows targets to tier 2] (rust-lang/rust#121712): `aarch64-pc-windows-gnullvm`, `i686-pc-windows-gnullvm`, and `x86_64-pc-windows-gnullvm`. Refer to Rust's [platform support page][platform-support-doc] for more information on Rust's tiered platform support. Libraries --------- - [Implement `FromIterator` for `(impl Default + Extend, impl Default + Extend)`.] (rust-lang/rust#107462) - [Implement `{Div,Rem}Assign<NonZero<X>>` on `X`.] (rust-lang/rust#121952) - [Document overrides of `clone_from()` in core/std.] (rust-lang/rust#122201) - [Link MSVC default lib in core.] (rust-lang/rust#122268) - [Caution against using `transmute` between pointers and integers.] (rust-lang/rust#122379) - [Enable frame pointers for the standard library.] (rust-lang/rust#122646) Stabilized APIs --------------- - [`{integer}::unchecked_add`] (https://doc.rust-lang.org/stable/core/primitive.i32.html#method.unchecked_add) - [`{integer}::unchecked_mul`] (https://doc.rust-lang.org/stable/core/primitive.i32.html#method.unchecked_mul) - [`{integer}::unchecked_sub`] (https://doc.rust-lang.org/stable/core/primitive.i32.html#method.unchecked_sub) - [`<[T]>::split_at_unchecked`] (https://doc.rust-lang.org/stable/core/primitive.slice.html#method.split_at_unchecked) - [`<[T]>::split_at_mut_unchecked`] (https://doc.rust-lang.org/stable/core/primitive.slice.html#method.split_at_mut_unchecked) - [`<[u8]>::utf8_chunks`] (https://doc.rust-lang.org/stable/core/primitive.slice.html#method.utf8_chunks) - [`str::Utf8Chunks`] (https://doc.rust-lang.org/stable/core/str/struct.Utf8Chunks.html) - [`str::Utf8Chunk`] (https://doc.rust-lang.org/stable/core/str/struct.Utf8Chunk.html) - [`<*const T>::is_aligned`] (https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.is_aligned) - [`<*mut T>::is_aligned`] (https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.is_aligned-1) - [`NonNull::is_aligned`] (https://doc.rust-lang.org/stable/core/ptr/struct.NonNull.html#method.is_aligned) - [`<*const [T]>::len`] (https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.len) - [`<*mut [T]>::len`] (https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.len-1) - [`<*const [T]>::is_empty`] (https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.is_empty) - [`<*mut [T]>::is_empty`] (https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.is_empty-1) - [`NonNull::<[T]>::is_empty`] (https://doc.rust-lang.org/stable/core/ptr/struct.NonNull.html#method.is_empty) - [`CStr::count_bytes`] (https://doc.rust-lang.org/stable/core/ffi/c_str/struct.CStr.html#method.count_bytes) - [`io::Error::downcast`] (https://doc.rust-lang.org/stable/std/io/struct.Error.html#method.downcast) - [`num::NonZero<T>`] (https://doc.rust-lang.org/stable/core/num/struct.NonZero.html) - [`path::absolute`] (https://doc.rust-lang.org/stable/std/path/fn.absolute.html) - [`proc_macro::Literal::byte_character`] (https://doc.rust-lang.org/stable/proc_macro/struct.Literal.html#method.byte_character) - [`proc_macro::Literal::c_string`] (https://doc.rust-lang.org/stable/proc_macro/struct.Literal.html#method.c_string) These APIs are now stable in const contexts: - [`Atomic*::into_inner`] (https://doc.rust-lang.org/stable/core/sync/atomic/struct.AtomicUsize.html#method.into_inner) - [`io::Cursor::new`] (https://doc.rust-lang.org/stable/std/io/struct.Cursor.html#method.new) - [`io::Cursor::get_ref`] (https://doc.rust-lang.org/stable/std/io/struct.Cursor.html#method.get_ref) - [`io::Cursor::position`] (https://doc.rust-lang.org/stable/std/io/struct.Cursor.html#method.position) - [`io::empty`] (https://doc.rust-lang.org/stable/std/io/fn.empty.html) - [`io::repeat`] (https://doc.rust-lang.org/stable/std/io/fn.repeat.html) - [`io::sink`] (https://doc.rust-lang.org/stable/std/io/fn.sink.html) - [`panic::Location::caller`] (https://doc.rust-lang.org/stable/std/panic/struct.Location.html#method.caller) - [`panic::Location::file`] (https://doc.rust-lang.org/stable/std/panic/struct.Location.html#method.file) - [`panic::Location::line`] (https://doc.rust-lang.org/stable/std/panic/struct.Location.html#method.line) - [`panic::Location::column`] (https://doc.rust-lang.org/stable/std/panic/struct.Location.html#method.column) Cargo ----- - [Prevent dashes in `lib.name`, always normalizing to `_`.] (rust-lang/cargo#12783) - [Stabilize MSRV-aware version requirement selection in `cargo add`.] (rust-lang/cargo#13608) - [Switch to using `gitoxide` by default for listing files.] (rust-lang/cargo#13696) Rustdoc ----- - [Always display stability version even if it's the same as the containing item.] (rust-lang/rust#118441) - [Show a single search result for items with multiple paths.] (rust-lang/rust#119912) - [Support typing `/` in docs to begin a search.] (rust-lang/rust#123355) Misc ---- Compatibility Notes ------------------- - [Update the minimum external LLVM to 17.] (rust-lang/rust#122649) - [`RustcEncodable` and `RustcDecodable` are soft-destabilized, to be removed from the prelude in next edition.] (rust-lang/rust#116016) - [The `wasm_c_abi` future-incompatibility lint will warn about use of the non-spec-compliant C ABI.] (rust-lang/rust#117918) Use `wasm-bindgen v0.2.88` to generate forward-compatible bindings. - [Check return types of function types for well-formedness] (rust-lang/rust#115538) Version 1.78.0 (2024-05-02) =========================== Language -------- - [Stabilize `#[cfg(target_abi = ...)]`] (rust-lang/rust#119590) - [Stabilize the `#[diagnostic]` namespace and `#[diagnostic::on_unimplemented]` attribute] (rust-lang/rust#119888) - [Make async-fn-in-trait implementable with concrete signatures] (rust-lang/rust#120103) - [Make matching on NaN a hard error, and remove the rest of `illegal_floating_point_literal_pattern`] (rust-lang/rust#116284) - [static mut: allow mutable reference to arbitrary types, not just slices and arrays] (rust-lang/rust#117614) - [Extend `invalid_reference_casting` to include references casting to bigger memory layout] (rust-lang/rust#118983) - [Add `non_contiguous_range_endpoints` lint for singleton gaps after exclusive ranges] (rust-lang/rust#118879) - [Add `wasm_c_abi` lint for use of older wasm-bindgen versions] (rust-lang/rust#117918) This lint currently only works when using Cargo. - [Update `indirect_structural_match` and `pointer_structural_match` lints to match RFC] (rust-lang/rust#120423) - [Make non-`PartialEq`-typed consts as patterns a hard error] (rust-lang/rust#120805) - [Split `refining_impl_trait` lint into `_reachable`, `_internal` variants] (rust-lang/rust#121720) - [Remove unnecessary type inference when using associated types inside of higher ranked `where`-bounds] (rust-lang/rust#119849) - [Weaken eager detection of cyclic types during type inference] (rust-lang/rust#119989) - [`trait Trait: Auto {}`: allow upcasting from `dyn Trait` to `dyn Auto`] (rust-lang/rust#119338) Compiler -------- - [Made `INVALID_DOC_ATTRIBUTES` lint deny by default] (rust-lang/rust#111505) - [Increase accuracy of redundant `use` checking] (rust-lang/rust#117772) - [Suggest moving definition if non-found macro_rules! is defined later] (rust-lang/rust#121130) - [Lower transmutes from int to pointer type as gep on null] (rust-lang/rust#121282) Target changes: - [Windows tier 1 targets now require at least Windows 10] (rust-lang/rust#115141) - [Enable CMPXCHG16B, SSE3, SAHF/LAHF and 128-bit Atomics in tier 1 Windows] (rust-lang/rust#120820) - [Add `wasm32-wasip1` tier 2 (without host tools) target] (rust-lang/rust#120468) - [Add `wasm32-wasip2` tier 3 target] (rust-lang/rust#119616) - [Rename `wasm32-wasi-preview1-threads` to `wasm32-wasip1-threads`] (rust-lang/rust#122170) - [Add `arm64ec-pc-windows-msvc` tier 3 target] (rust-lang/rust#119199) - [Add `armv8r-none-eabihf` tier 3 target for the Cortex-R52] (rust-lang/rust#110482) - [Add `loongarch64-unknown-linux-musl` tier 3 target] (rust-lang/rust#121832) Refer to Rust's [platform support page][platform-support-doc] for more information on Rust's tiered platform support. Libraries --------- - [Bump Unicode to version 15.1.0, regenerate tables] (rust-lang/rust#120777) - [Make align_offset, align_to well-behaved in all cases] (rust-lang/rust#121201) - [PartialEq, PartialOrd: document expectations for transitive chains] (rust-lang/rust#115386) - [Optimize away poison guards when std is built with panic=abort] (rust-lang/rust#100603) - [Replace pthread `RwLock` with custom implementation] (rust-lang/rust#110211) - [Implement unwind safety for Condvar on all platforms] (rust-lang/rust#121768) - [Add ASCII fast-path for `char::is_grapheme_extended`] (rust-lang/rust#121138) Stabilized APIs --------------- - [`impl Read for &Stdin`] (https://doc.rust-lang.org/stable/std/io/struct.Stdin.html#impl-Read-for-%26Stdin) - [Accept non `'static` lifetimes for several `std::error::Error` related implementations] (rust-lang/rust#113833) - [Make `impl<Fd: AsFd>` impl take `?Sized`] (rust-lang/rust#114655) - [`impl From<TryReserveError> for io::Error`] (https://doc.rust-lang.org/stable/std/io/struct.Error.html#impl-From%3CTryReserveError%3E-for-Error) These APIs are now stable in const contexts: - [`Barrier::new()`] (https://doc.rust-lang.org/stable/std/sync/struct.Barrier.html#method.new) Cargo ----- - [Stabilize lockfile v4](rust-lang/cargo#12852) - [Respect `rust-version` when generating lockfile] (rust-lang/cargo#12861) - [Control `--charset` via auto-detecting config value] (rust-lang/cargo#13337) - [Support `target.<triple>.rustdocflags` officially] (rust-lang/cargo#13197) - [Stabilize global cache data tracking] (rust-lang/cargo#13492) Misc ---- - [rustdoc: add `--test-builder-wrapper` arg to support wrappers such as RUSTC_WRAPPER when building doctests] (rust-lang/rust#114651) Compatibility Notes ------------------- - [Many unsafe precondition checks now run for user code with debug assertions enabled] (rust-lang/rust#120594) This change helps users catch undefined behavior in their code, though the details of how much is checked are generally not stable. - [riscv only supports split_debuginfo=off for now] (rust-lang/rust#120518) - [Consistently check bounds on hidden types of `impl Trait`] (rust-lang/rust#121679) - [Change equality of higher ranked types to not rely on subtyping] (rust-lang/rust#118247) - [When called, additionally check bounds on normalized function return type] (rust-lang/rust#118882) - [Expand coverage for `arithmetic_overflow` lint] (rust-lang/rust#119432) Internal Changes ---------------- These changes do not affect any public interfaces of Rust, but they represent significant improvements to the performance or internals of rustc and related tools. - [Update to LLVM 18](rust-lang/rust#120055) - [Build `rustc` with 1CGU on `x86_64-pc-windows-msvc`] (rust-lang/rust#112267) - [Build `rustc` with 1CGU on `x86_64-apple-darwin`] (rust-lang/rust#112268) - [Introduce `run-make` V2 infrastructure, a `run_make_support` library and port over 2 tests as example] (rust-lang/rust#113026) - [Windows: Implement condvar, mutex and rwlock using futex] (rust-lang/rust#121956) Version 1.77.0 (2024-03-21) ========================== - [Reveal opaque types within the defining body for exhaustiveness checking.] (rust-lang/rust#116821) - [Stabilize C-string literals.] (rust-lang/rust#117472) - [Stabilize THIR unsafeck.] (rust-lang/rust#117673) - [Add lint `static_mut_refs` to warn on references to mutable statics.] (rust-lang/rust#117556) - [Support async recursive calls (as long as they have indirection).] (rust-lang/rust#117703) - [Undeprecate lint `unstable_features` and make use of it in the compiler.] (rust-lang/rust#118639) - [Make inductive cycles in coherence ambiguous always.] (rust-lang/rust#118649) - [Get rid of type-driven traversal in const-eval interning] (rust-lang/rust#119044), only as a [future compatiblity lint] (rust-lang/rust#122204) for now. - [Deny braced macro invocations in let-else.] (rust-lang/rust#119062) Compiler -------- - [Include lint `soft_unstable` in future breakage reports.] (rust-lang/rust#116274) - [Make `i128` and `u128` 16-byte aligned on x86-based targets.] (rust-lang/rust#116672) - [Use `--verbose` in diagnostic output.] (rust-lang/rust#119129) - [Improve spacing between printed tokens.] (rust-lang/rust#120227) - [Merge the `unused_tuple_struct_fields` lint into `dead_code`.] (rust-lang/rust#118297) - [Error on incorrect implied bounds in well-formedness check] (rust-lang/rust#118553), with a temporary exception for Bevy. - [Fix coverage instrumentation/reports for non-ASCII source code.] (rust-lang/rust#119033) - [Fix `fn`/`const` items implied bounds and well-formedness check.] (rust-lang/rust#120019) - [Promote `riscv32{im|imafc}-unknown-none-elf` targets to tier 2.] (rust-lang/rust#118704) - Add several new tier 3 targets: - [`aarch64-unknown-illumos`] (rust-lang/rust#112936) - [`hexagon-unknown-none-elf`] (rust-lang/rust#117601) - [`riscv32imafc-esp-espidf`] (rust-lang/rust#119738) - [`riscv32im-risc0-zkvm-elf`] (rust-lang/rust#117958) Refer to Rust's [platform support page][platform-support-doc] for more information on Rust's tiered platform support. Libraries --------- - [Implement `From<&[T; N]>` for `Cow<[T]>`.] (rust-lang/rust#113489) - [Remove special-case handling of `vec.split_off (0)`.](rust-lang/rust#119917) Stabilized APIs --------------- - [`array::each_ref`] (https://doc.rust-lang.org/stable/std/primitive.array.html#method.each_ref) - [`array::each_mut`] (https://doc.rust-lang.org/stable/std/primitive.array.html#method.each_mut) - [`core::net`] (https://doc.rust-lang.org/stable/core/net/index.html) - [`f32::round_ties_even`] (https://doc.rust-lang.org/stable/std/primitive.f32.html#method.round_ties_even) - [`f64::round_ties_even`] (https://doc.rust-lang.org/stable/std/primitive.f64.html#method.round_ties_even) - [`mem::offset_of!`] (https://doc.rust-lang.org/stable/std/mem/macro.offset_of.html) - [`slice::first_chunk`] (https://doc.rust-lang.org/stable/std/primitive.slice.html#method.first_chunk) - [`slice::first_chunk_mut`] (https://doc.rust-lang.org/stable/std/primitive.slice.html#method.first_chunk_mut) - [`slice::split_first_chunk`] (https://doc.rust-lang.org/stable/std/primitive.slice.html#method.split_first_chunk) - [`slice::split_first_chunk_mut`] (https://doc.rust-lang.org/stable/std/primitive.slice.html#method.split_first_chunk_mut) - [`slice::last_chunk`] (https://doc.rust-lang.org/stable/std/primitive.slice.html#method.last_chunk) - [`slice::last_chunk_mut`] (https://doc.rust-lang.org/stable/std/primitive.slice.html#method.last_chunk_mut) - [`slice::split_last_chunk`] (https://doc.rust-lang.org/stable/std/primitive.slice.html#method.split_last_chunk) - [`slice::split_last_chunk_mut`] (https://doc.rust-lang.org/stable/std/primitive.slice.html#method.split_last_chunk_mut) - [`slice::chunk_by`] (https://doc.rust-lang.org/stable/std/primitive.slice.html#method.chunk_by) - [`slice::chunk_by_mut`] (https://doc.rust-lang.org/stable/std/primitive.slice.html#method.chunk_by_mut) - [`Bound::map`] (https://doc.rust-lang.org/stable/std/ops/enum.Bound.html#method.map) - [`File::create_new`] (https://doc.rust-lang.org/stable/std/fs/struct.File.html#method.create_new) - [`Mutex::clear_poison`] (https://doc.rust-lang.org/stable/std/sync/struct.Mutex.html#method.clear_poison) - [`RwLock::clear_poison`] (https://doc.rust-lang.org/stable/std/sync/struct.RwLock.html#method.clear_poison) Cargo ----- - [Extend the build directive syntax with `cargo::`.] (rust-lang/cargo#12201) - [Stabilize metadata `id` format as `PackageIDSpec`.] (rust-lang/cargo#12914) - [Pull out as `cargo-util-schemas` as a crate.] (rust-lang/cargo#13178) - [Strip all debuginfo when debuginfo is not requested.] (rust-lang/cargo#13257) - [Inherit jobserver from env for all kinds of runners.] (rust-lang/cargo#12776) - [Deprecate rustc plugin support in cargo.] (rust-lang/cargo#13248) Rustdoc ----- - [Allows links in markdown headings.] (rust-lang/rust#117662) - [Search for tuples and unit by type with `()`.] (rust-lang/rust#118194) - [Clean up the source sidebar's hide button.] (rust-lang/rust#119066) - [Prevent JS injection from `localStorage`.] (rust-lang/rust#120250) Misc ---- - [Recommend version-sorting for all sorting in style guide.] (rust-lang/rust#115046) Internal Changes ---------------- These changes do not affect any public interfaces of Rust, but they represent significant improvements to the performance or internals of rustc and related tools. - [Add more weirdness to `weird-exprs.rs`.] (rust-lang/rust#119028)

rustbot assigned cjgillot Oct 12, 2023

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels Oct 12, 2023

rustbot added the llvm-main Marks PRs that are making Rust work with LLVM main (this label is consumed by CI tooling) label Oct 12, 2023