Improve `derive(Debug)` #98190

nnethercote · 2022-06-17T07:09:50Z

r? @ghost

nnethercote · 2022-06-17T07:10:04Z

@bors try @rust-timer queue

rust-timer · 2022-06-17T07:10:06Z

Awaiting bors try build completion.

@rustbot label: +S-waiting-on-perf

bors · 2022-06-17T07:10:13Z

⌛ Trying commit 196abcbb4334341a28f4aa9b2470323e0fce89fb with merge 4f6798a53481778eba489b676fe20c8769302ce3...

bors · 2022-06-17T09:00:36Z

☀️ Try build successful - checks-actions
Build commit: 4f6798a53481778eba489b676fe20c8769302ce3 (4f6798a53481778eba489b676fe20c8769302ce3)

rust-timer · 2022-06-17T09:00:38Z

Queued 4f6798a53481778eba489b676fe20c8769302ce3 with parent 3cf1275, future comparison URL.

rust-timer · 2022-06-17T10:18:05Z

Finished benchmarking commit (4f6798a53481778eba489b676fe20c8769302ce3): comparison url.

Instruction count

Primary benchmarks: mixed results
Secondary benchmarks: mixed results

	mean¹	max	count²
Regressions 😿 (primary)	1.4%	2.9%	3
Regressions 😿 (secondary)	1.4%	2.4%	10
Improvements 🎉 (primary)	-0.9%	-4.6%	104
Improvements 🎉 (secondary)	-3.4%	-10.1%	24
All 😿🎉 (primary)	-0.8%	-4.6%	107

Max RSS (memory usage)

Results

Primary benchmarks: 🎉 relevant improvements found
Secondary benchmarks: 🎉 relevant improvements found

	mean¹	max	count²
Regressions 😿 (primary)	N/A	N/A	0
Regressions 😿 (secondary)	N/A	N/A	0
Improvements 🎉 (primary)	-3.0%	-6.3%	6
Improvements 🎉 (secondary)	-1.9%	-2.2%	4
All 😿🎉 (primary)	-3.0%	-6.3%	6

Cycles

Results

Primary benchmarks: mixed results
Secondary benchmarks: 🎉 relevant improvements found

	mean¹	max	count²
Regressions 😿 (primary)	3.9%	5.0%	2
Regressions 😿 (secondary)	N/A	N/A	0
Improvements 🎉 (primary)	-2.5%	-5.0%	13
Improvements 🎉 (secondary)	-5.5%	-10.1%	13
All 😿🎉 (primary)	-1.7%	-5.0%	15

If you disagree with this performance assessment, please file an issue in rust-lang/rustc-perf.

Benchmarking this pull request likely means that it is perf-sensitive, so we're automatically marking it as not fit for rolling up. While you can manually mark this PR as fit for rollup, we strongly recommend not doing so since this PR may lead to changes in compiler perf.

Next Steps: If you can justify the regressions found in this try perf run, please indicate this with @rustbot label: +perf-regression-triaged along with sufficient written justification. If you cannot justify the regressions please fix the regressions and do another perf run. If the next run shows neutral or positive results, the label will be automatically removed.

@bors rollup=never
@rustbot label: +S-waiting-on-review -S-waiting-on-perf +perf-regression

the arithmetic mean of the percent change ↩ ↩² ↩³
number of relevant changes ↩ ↩² ↩³

nnethercote · 2022-06-17T10:28:08Z

This PR is me experimenting with ways to shrink the size of the code generated by derive(Debug). The motivation was complaints about the size of binaries produced by Rust (here and here) but compile speed is also affected. The preliminary results are quite promising.

nnethercote · 2022-06-21T07:43:53Z

I learned today that @scottmcm tried much the same thing in #95637, with mixed results. I have incorporated some of the code from that PR here. The main difference is that for small numbers of fields, I am passing names and values directly rather than putting them into an array. That seems to make a big difference, performance-wise.

@bors try @rust-timer queue

rust-timer · 2022-06-21T07:43:55Z

Awaiting bors try build completion.

@rustbot label: +S-waiting-on-perf

bors · 2022-06-21T07:44:01Z

⌛ Trying commit b949e0ed572645b0c8093e9b2d09b48da9fa8268 with merge 58b1508314a0f5e3086564b8240c4ad61302c499...

bors · 2022-06-21T09:37:11Z

☀️ Try build successful - checks-actions
Build commit: 58b1508314a0f5e3086564b8240c4ad61302c499 (58b1508314a0f5e3086564b8240c4ad61302c499)

rust-timer · 2022-06-21T09:37:12Z

Queued 58b1508314a0f5e3086564b8240c4ad61302c499 with parent 42dcf70, future comparison URL.

rust-timer · 2022-06-21T11:08:51Z

Finished benchmarking commit (58b1508314a0f5e3086564b8240c4ad61302c499): comparison url.

Instruction count

Primary benchmarks: mixed results
Secondary benchmarks: mixed results

	mean¹	max	count²
Regressions 😿 (primary)	0.9%	3.0%	7
Regressions 😿 (secondary)	0.9%	1.4%	9
Improvements 🎉 (primary)	-1.0%	-5.2%	114
Improvements 🎉 (secondary)	-2.9%	-10.0%	30
All 😿🎉 (primary)	-0.9%	-5.2%	121

Max RSS (memory usage)

Results

Primary benchmarks: mixed results
Secondary benchmarks: mixed results

	mean¹	max	count²
Regressions 😿 (primary)	4.9%	7.9%	3
Regressions 😿 (secondary)	2.4%	3.0%	5
Improvements 🎉 (primary)	-2.6%	-6.7%	11
Improvements 🎉 (secondary)	-2.8%	-3.6%	3
All 😿🎉 (primary)	-1.0%	7.9%	14

Cycles

Results

Primary benchmarks: mixed results
Secondary benchmarks: 🎉 relevant improvements found

	mean¹	max	count²
Regressions 😿 (primary)	3.6%	6.4%	3
Regressions 😿 (secondary)	N/A	N/A	0
Improvements 🎉 (primary)	-2.9%	-5.3%	15
Improvements 🎉 (secondary)	-5.1%	-10.1%	15
All 😿🎉 (primary)	-1.8%	6.4%	18

If you disagree with this performance assessment, please file an issue in rust-lang/rustc-perf.

Benchmarking this pull request likely means that it is perf-sensitive, so we're automatically marking it as not fit for rolling up. While you can manually mark this PR as fit for rollup, we strongly recommend not doing so since this PR may lead to changes in compiler perf.

Next Steps: If you can justify the regressions found in this try perf run, please indicate this with @rustbot label: +perf-regression-triaged along with sufficient written justification. If you cannot justify the regressions please fix the regressions and do another perf run. If the next run shows neutral or positive results, the label will be automatically removed.

@bors rollup=never
@rustbot label: +S-waiting-on-review -S-waiting-on-perf +perf-regression

the arithmetic mean of the percent change ↩ ↩² ↩³
number of relevant changes ↩ ↩² ↩³

nnethercote · 2022-06-22T04:14:19Z

The performance results are generally very good, with 144 improvements and 16 regressions.

Among the regressions:

5 are from opt full runs. The other runs for the affected benchmarks are universally good. E.g. regex-1.5.5 has the worst opt full regression of 2.97%, but also has 22 runs that improve. So this shows that it's something about opt full. My best guess is that the codegen unit boundaries are being perturbed (because this PR significantly changes the code of the benchmarks) and for some reason this is showing up in opt full runs more than anywhere else. There are still 7 opt full improvements, including a 10% improvement for the derive stress test.
7 are for tt-muncher, which doesn't use derive(Debug). It's < 1% regression in every case. I was able to partially reproduce, but local investigation didn't turn up anything of interest.
2 are for serde_derive-1.0.136, which doesn't use derive(Debug). I couldn't reproduce these regressions locally.
2 are for externs, which doesn't use derive(Debug). I couldn't reproduce these regressions locally.

I think these results are clearly good enough for merging, and I'm not much worried by the regressions.

@rustbot label: +perf-regression-triaged

nnethercote · 2022-06-22T04:18:37Z

r? @scottmcm

Though please forward the review to anyone else who is more appropriate.

nnethercote · 2022-06-22T04:18:54Z

@bors try @rust-timer queue

nnethercote · 2022-06-22T20:50:44Z

Thank you for the fast review.

We definitely don't want to roll this up, because it has known large performance effects.

@bors rollup=never

scottmcm · 2022-06-22T21:02:23Z

Oh, right, I forgot perfbot already set never. Thanks for fixing.

The new names are more accurate. Co-authored-by: Scott McMurray <scottmcm@users.noreply.github.com>

This commit adds new methods that combine sequences of existing formatting methods. - `Formatter::debug_{tuple,struct}_field[12345]_finish`, equivalent to a `Formatter::debug_{tuple,struct}` + N x `Debug{Tuple,Struct}::field` + `Debug{Tuple,Struct}::finish` call sequence. - `Formatter::debug_{tuple,struct}_fields_finish` is similar, but can handle any number of fields by using arrays. These new methods are all marked as `doc(hidden)` and unstable. They are intended for the compiler's own use. Special-casing up to 5 fields gives significantly better performance results than always using arrays (as was tried in rust-lang#95637). The commit also changes the `Debug` deriving code to use these new methods. For example, where the old `Debug` code for a struct with two fields would be like this: ``` fn fmt(&self, f: &mut ::core::fmt::Formatter) -> ::core::fmt::Result { match *self { Self { f1: ref __self_0_0, f2: ref __self_0_1, } => { let debug_trait_builder = &mut ::core::fmt::Formatter::debug_struct(f, "S2"); let _ = ::core::fmt::DebugStruct::field(debug_trait_builder, "f1", &&(*__self_0_0)); let _ = ::core::fmt::DebugStruct::field(debug_trait_builder, "f2", &&(*__self_0_1)); ::core::fmt::DebugStruct::finish(debug_trait_builder) } } } ``` the new code is like this: ``` fn fmt(&self, f: &mut ::core::fmt::Formatter) -> ::core::fmt::Result { match *self { Self { f1: ref __self_0_0, f2: ref __self_0_1, } => ::core::fmt::Formatter::debug_struct_field2_finish( f, "S2", "f1", &&(*__self_0_0), "f2", &&(*__self_0_1), ), } } ``` This shrinks the code produced for `Debug` instances considerably, reducing compile times and binary sizes. Co-authored-by: Scott McMurray <scottmcm@users.noreply.github.com>

The handwritten versions more compact and easier to read than the derived version.

nnethercote · 2022-06-24T00:25:45Z

I made some minor improvement, nothing really noteworthy.

@bors r=scottmcm

bors · 2022-06-24T00:25:47Z

📌 Commit 20f0cda has been approved by scottmcm

bors · 2022-06-26T15:00:06Z

⌛ Testing commit 20f0cda with merge 788dded...

bors · 2022-06-26T17:15:41Z

☀️ Test successful - checks-actions
Approved by: scottmcm
Pushing 788dded to master...

rust-timer · 2022-06-26T18:55:51Z

Finished benchmarking commit (788dded): comparison url.

Instruction count

Primary benchmarks: 🎉 relevant improvements found
Secondary benchmarks: mixed results

	mean¹	max	count²
Regressions 😿 (primary)	0.5%	0.6%	4
Regressions 😿 (secondary)	0.5%	0.8%	13
Improvements 🎉 (primary)	-1.0%	-5.3%	120
Improvements 🎉 (secondary)	-1.8%	-10.3%	69
All 😿🎉 (primary)	-1.0%	-5.3%	124

Max RSS (memory usage)

Results

Primary benchmarks: mixed results
Secondary benchmarks: 🎉 relevant improvements found

	mean¹	max	count²
Regressions 😿 (primary)	3.0%	6.9%	3
Regressions 😿 (secondary)	1.0%	1.0%	1
Improvements 🎉 (primary)	-2.8%	-6.5%	6
Improvements 🎉 (secondary)	-3.1%	-3.8%	8
All 😿🎉 (primary)	-0.9%	6.9%	9

Cycles

Results

Primary benchmarks: 🎉 relevant improvements found
Secondary benchmarks: 🎉 relevant improvements found

	mean¹	max	count²
Regressions 😿 (primary)	2.2%	2.4%	2
Regressions 😿 (secondary)	N/A	N/A	0
Improvements 🎉 (primary)	-3.0%	-5.7%	27
Improvements 🎉 (secondary)	-5.9%	-10.0%	14
All 😿🎉 (primary)	-2.6%	-5.7%	29

If you disagree with this performance assessment, please file an issue in rust-lang/rustc-perf.

@rustbot label: -perf-regression

the arithmetic mean of the percent change ↩ ↩² ↩³
number of relevant changes ↩ ↩² ↩³

nnethercote · 2022-06-26T21:16:41Z

Interesting opt full results again. Pre-merge results:

Benchmark	Profile	Scenario	% Change	Significance Factor?
regex-1.5.5	opt	full	2.87%	8.14x
diesel-1.4.8	opt	full	-1.28%	6.01x
html5ever-0.26.0	opt	full	-0.93%	4.15x
webrender-2022	opt	full	-0.66%	2.28x
serde-1.0.136	opt	full	-0.55%	3.42x
image-0.24.1	opt	full	0.50%	2.84x
cranelift-codegen-0.82.1	opt	full	-0.49%	1.92x
cargo-0.60.0	opt	full	0.45%	1.61x
clap-3.1.6	opt	full	-0.40%	1.58x

Post-merge results:

Benchmark	Profile	Scenario	% Change	Significance Factor?
html5ever-0.26.0	opt	full	-0.86%	3.41x
regex-1.5.5	opt	full	0.64%	1.76x
diesel-1.4.8	opt	full	-0.64%	2.72x
image-0.24.1	opt	full	0.61%	3.61x
cranelift-codegen-0.82.1	opt	full	-0.55%	2.10x
webrender-2022	opt	full	-0.54%	2.28x
serde-1.0.136	opt	full	-0.31%	1.91x

The post-merge results were less extreme in general, for both improvements and regressions. Clearly there's a lot of variation there, presumably due to the changes in codegen-unit boundaries.

But overall the perf results are still super-duper.

nnethercote · 2022-06-27T00:35:38Z

Also, the significant factors on all those opt full cases are quite low, which fits with the other observations.

nnethercote · 2022-07-14T02:25:19Z

@hudson-ayers You might be interested in this PR! It was inspired by part of your "Tighten Rust's Belt" paper at LCTES'22.

hudson-ayers · 2022-07-14T03:40:47Z

Wow, this is great to see! Thank you for working on this, and glad that my work was able to inspire it! I tested this out on one of my motivating examples from awhile back -- Tock's UdpEndpoint type -- and found the size of the generated debug code shrank by 176 bytes as a result of this PR. This sort of savings is very meaningful for low resource embedded systems with < 500kB of flash.

Pkgsrc changes: * Add patch to fix vendor/kqueue issue (on 32-bit hosts) * Adjust other patches & line numbers * Version bumps & checksum changes. Upstream changes: Version 1.64.0 (2022-09-22) =========================== Language -------- - [Unions with mutable references or tuples of allowed types are now allowed](rust-lang/rust#97995) - It is now considered valid to deallocate memory pointed to by a shared reference `&T` [if every byte in `T` is inside an `UnsafeCell`](rust-lang/rust#98017) - Unused tuple struct fields are now warned against in an allow-by-default lint, [`unused_tuple_struct_fields`] (rust-lang/rust#95977), similar to the existing warning for unused struct fields. This lint will become warn-by-default in the future. Compiler -------- - [Add Nintendo Switch as tier 3 target] (rust-lang/rust#88991) - Refer to Rust's [platform support page][platform-support-doc] for more information on Rust's tiered platform support. - [Only compile `#[used]` as llvm.compiler.used for ELF targets] (rust-lang/rust#93718) - [Add the `--diagnostic-width` compiler flag to define the terminal width.] (rust-lang/rust#95635) - [Add support for link-flavor `rust-lld` for iOS, tvOS and watchOS] (rust-lang/rust#98771) Libraries --------- - [Remove restrictions on compare-exchange memory ordering.] (rust-lang/rust#98383) - You can now `write!` or `writeln!` into an `OsString`: [Implement `fmt::Write` for `OsString`](rust-lang/rust#97915) - [Make RwLockReadGuard covariant] (rust-lang/rust#96820) - [Implement `FusedIterator` for `std::net::[Into]Incoming`] (rust-lang/rust#97300) - [`impl<T: AsRawFd> AsRawFd for {Arc,Box}<T>`] (rust-lang/rust#97437) - [`ptr::copy` and `ptr::swap` are doing untyped copies] (rust-lang/rust#97712) - [Add cgroupv1 support to `available_parallelism`] (rust-lang/rust#97925) - [Mitigate many incorrect uses of `mem::uninitialized`] (rust-lang/rust#99182) Stabilized APIs --------------- - [`future::IntoFuture`] (https://doc.rust-lang.org/stable/std/future/trait.IntoFuture.html) - [`future::poll_fn`] (https://doc.rust-lang.org/stable/std/future/fn.poll_fn.html) - [`task::ready!`] (https://doc.rust-lang.org/stable/std/task/macro.ready.html) - [`num::NonZero*::checked_mul`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroUsize.html#method.checked_mul) - [`num::NonZero*::checked_pow`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroUsize.html#method.checked_pow) - [`num::NonZero*::saturating_mul`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroUsize.html#method.saturating_mul) - [`num::NonZero*::saturating_pow`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroUsize.html#method.saturating_pow) - [`num::NonZeroI*::abs`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroIsize.html#method.abs) - [`num::NonZeroI*::checked_abs`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroIsize.html#method.checked_abs) - [`num::NonZeroI*::overflowing_abs`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroIsize.html#method.overflowing_abs) - [`num::NonZeroI*::saturating_abs`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroIsize.html#method.saturating_abs) - [`num::NonZeroI*::unsigned_abs`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroIsize.html#method.unsigned_abs) - [`num::NonZeroI*::wrapping_abs`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroIsize.html#method.wrapping_abs) - [`num::NonZeroU*::checked_add`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroUsize.html#method.checked_add) - [`num::NonZeroU*::checked_next_power_of_two`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroUsize.html#method.checked_next_power_of_two) - [`num::NonZeroU*::saturating_add`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroUsize.html#method.saturating_add) - [`os::unix::process::CommandExt::process_group`] (https://doc.rust-lang.org/stable/std/os/unix/process/trait.CommandExt.html#tymethod.process_group) - [`os::windows::fs::FileTypeExt::is_symlink_dir`] (https://doc.rust-lang.org/stable/std/os/windows/fs/trait.FileTypeExt.html#tymethod.is_symlink_dir) - [`os::windows::fs::FileTypeExt::is_symlink_file`] (https://doc.rust-lang.org/stable/std/os/windows/fs/trait.FileTypeExt.html#tymethod.is_symlink_file) These types were previously stable in `std::ffi`, but are now also available in `core` and `alloc`: - [`core::ffi::CStr`] (https://doc.rust-lang.org/stable/core/ffi/struct.CStr.html) - [`core::ffi::FromBytesWithNulError`] (https://doc.rust-lang.org/stable/core/ffi/struct.FromBytesWithNulError.html) - [`alloc::ffi::CString`] (https://doc.rust-lang.org/stable/alloc/ffi/struct.CString.html) - [`alloc::ffi::FromVecWithNulError`] (https://doc.rust-lang.org/stable/alloc/ffi/struct.FromVecWithNulError.html) - [`alloc::ffi::IntoStringError`] (https://doc.rust-lang.org/stable/alloc/ffi/struct.IntoStringError.html) - [`alloc::ffi::NulError`] (https://doc.rust-lang.org/stable/alloc/ffi/struct.NulError.html) These types were previously stable in `std::os::raw`, but are now also available in `core::ffi` and `std::ffi`: - [`ffi::c_char`] (https://doc.rust-lang.org/stable/std/ffi/type.c_char.html) - [`ffi::c_double`] (https://doc.rust-lang.org/stable/std/ffi/type.c_double.html) - [`ffi::c_float`] (https://doc.rust-lang.org/stable/std/ffi/type.c_float.html) - [`ffi::c_int`] (https://doc.rust-lang.org/stable/std/ffi/type.c_int.html) - [`ffi::c_long`] (https://doc.rust-lang.org/stable/std/ffi/type.c_long.html) - [`ffi::c_longlong`] (https://doc.rust-lang.org/stable/std/ffi/type.c_longlong.html) - [`ffi::c_schar`] (https://doc.rust-lang.org/stable/std/ffi/type.c_schar.html) - [`ffi::c_short`] (https://doc.rust-lang.org/stable/std/ffi/type.c_short.html) - [`ffi::c_uchar`] (https://doc.rust-lang.org/stable/std/ffi/type.c_uchar.html) - [`ffi::c_uint`] (https://doc.rust-lang.org/stable/std/ffi/type.c_uint.html) - [`ffi::c_ulong`] (https://doc.rust-lang.org/stable/std/ffi/type.c_ulong.html) - [`ffi::c_ulonglong`] (https://doc.rust-lang.org/stable/std/ffi/type.c_ulonglong.html) - [`ffi::c_ushort`] (https://doc.rust-lang.org/stable/std/ffi/type.c_ushort.html) These APIs are now usable in const contexts: - [`slice::from_raw_parts`] (https://doc.rust-lang.org/stable/core/slice/fn.from_raw_parts.html) Cargo ----- - [Packages can now inherit settings from the workspace so that the settings can be centralized in one place.] (rust-lang/cargo#10859) See [`workspace.package`](https://doc.rust-lang.org/nightly/cargo/reference/workspaces.html#the-workspacepackage-table) and [`workspace.dependencies`](https://doc.rust-lang.org/nightly/cargo/reference/workspaces.html#the-workspacedependencies-table) for more details on how to define these common settings. - [Cargo commands can now accept multiple `--target` flags to build for multiple targets at once] (rust-lang/cargo#10766), and the [`build.target`](https://doc.rust-lang.org/nightly/cargo/reference/config.html#buildtarget) config option may now take an array of multiple targets. - [The `--jobs` argument can now take a negative number to count backwards from the max CPUs.] (rust-lang/cargo#10844) - [`cargo add` will now update `Cargo.lock`.] (rust-lang/cargo#10902) - [Added](rust-lang/cargo#10838) the [`--crate-type`](https://doc.rust-lang.org/nightly/cargo/commands/cargo-rustc.html#option-cargo-rustc---crate-type) flag to `cargo rustc` to override the crate type. - [Significantly improved the performance fetching git dependencies from GitHub when using a hash in the `rev` field.] (rust-lang/cargo#10079) Misc ---- - [The `rust-analyzer` rustup component is now available on the stable channel.] (rust-lang/rust#98640) Compatibility Notes ------------------- - The minimum required versions for all `-linux-gnu` targets are now at least kernel 3.2 and glibc 2.17, for targets that previously supported older versions: [Increase the minimum linux-gnu versions](rust-lang/rust#95026) - [Network primitives are now implemented with the ideal Rust layout, not the C system layout] (rust-lang/rust#78802). This can cause problems when transmuting the types. - [Add assertion that `transmute_copy`'s `U` is not larger than `T`] (rust-lang/rust#98839) - [A soundness bug in `BTreeMap` was fixed] (rust-lang/rust#99413) that allowed data it was borrowing to be dropped before the container. - [The Drop behavior of C-like enums cast to ints has changed] (rust-lang/rust#96862). These are already discouraged by a compiler warning. - [Relate late-bound closure lifetimes to parent fn in NLL] (rust-lang/rust#98835) - [Errors at const-eval time are now in future incompatibility reports] (rust-lang/rust#97743) - On the `thumbv6m-none-eabi` target, some incorrect `asm!` statements were erroneously accepted if they used the high registers (r8 to r14) as an input/output operand. [This is no longer accepted] (rust-lang/rust#99155). - [`impl Trait` was accidentally accepted as the associated type value of return-position `impl Trait`] (rust-lang/rust#97346), without fulfilling all the trait bounds of that associated type, as long as the hidden type satisfies said bounds. This has been fixed. 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. - Windows builds now use profile-guided optimization, providing 10-20% improvements to compiler performance: [Utilize PGO for windows x64 rustc dist builds] (rust-lang/rust#96978) - [Stop keeping metadata in memory before writing it to disk] (rust-lang/rust#96544) - [compiletest: strip debuginfo by default for mode=ui] (rust-lang/rust#98140) - Many improvements to generated code for derives, including performance improvements: - [Don't use match-destructuring for derived ops on structs.] (rust-lang/rust#98446) - [Many small deriving cleanups] (rust-lang/rust#98741) - [More derive output improvements] (rust-lang/rust#98758) - [Clarify deriving code](rust-lang/rust#98915) - [Final derive output improvements] (rust-lang/rust#99046) - [Stop injecting `#[allow(unused_qualifications)]` in generated `derive` implementations](rust-lang/rust#99485) - [Improve `derive(Debug)`](rust-lang/rust#98190) - [Bump to clap 3](rust-lang/rust#98213) - [fully move dropck to mir](rust-lang/rust#98641) - [Optimize `Vec::insert` for the case where `index == len`.] (rust-lang/rust#98755) - [Convert rust-analyzer to an in-tree tool] (rust-lang/rust#99603)

Pkgsrc changes: * This package now contains rust-analyzer, so implicitly conflicts with that pkgsrc package. The same goes for the rust-src package. * Add NetBSD/arm6 port * Add unfinished NetBSD/mipsel port * Revert the use of the internal LLVM, should now build with the new pkgsrc LLVM (15). * Add depndence on compat80 for sparc64 to fix the build * Adapt patches * Add CHECK_INTERPRETER_SKIP for a few (mostly unused) files. (A proper fix may come later.) Upstream changes: Version 1.64.0 (2022-09-22) =========================== Language -------- - [Unions with mutable references or tuples of allowed types are now allowed](rust-lang/rust#97995) - It is now considered valid to deallocate memory pointed to by a shared reference `&T` [if every byte in `T` is inside an `UnsafeCell`](rust-lang/rust#98017) - Unused tuple struct fields are now warned against in an allow-by-default lint, [`unused_tuple_struct_fields`] (rust-lang/rust#95977), similar to the existing warning for unused struct fields. This lint will become warn-by-default in the future. Compiler -------- - [Add Nintendo Switch as tier 3 target] (rust-lang/rust#88991) - Refer to Rust's [platform support page][platform-support-doc] for more information on Rust's tiered platform support. - [Only compile `#[used]` as llvm.compiler.used for ELF targets] (rust-lang/rust#93718) - [Add the `--diagnostic-width` compiler flag to define the terminal width.] (rust-lang/rust#95635) - [Add support for link-flavor `rust-lld` for iOS, tvOS and watchOS] (rust-lang/rust#98771) Libraries --------- - [Remove restrictions on compare-exchange memory ordering.] (rust-lang/rust#98383) - You can now `write!` or `writeln!` into an `OsString`: [Implement `fmt::Write` for `OsString`](rust-lang/rust#97915) - [Make RwLockReadGuard covariant] (rust-lang/rust#96820) - [Implement `FusedIterator` for `std::net::[Into]Incoming`] (rust-lang/rust#97300) - [`impl<T: AsRawFd> AsRawFd for {Arc,Box}<T>`] (rust-lang/rust#97437) - [`ptr::copy` and `ptr::swap` are doing untyped copies] (rust-lang/rust#97712) - [Add cgroupv1 support to `available_parallelism`] (rust-lang/rust#97925) - [Mitigate many incorrect uses of `mem::uninitialized`] (rust-lang/rust#99182) Stabilized APIs --------------- - [`future::IntoFuture`] (https://doc.rust-lang.org/stable/std/future/trait.IntoFuture.html) - [`future::poll_fn`] (https://doc.rust-lang.org/stable/std/future/fn.poll_fn.html) - [`task::ready!`] (https://doc.rust-lang.org/stable/std/task/macro.ready.html) - [`num::NonZero*::checked_mul`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroUsize.html#method.checked_mul) - [`num::NonZero*::checked_pow`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroUsize.html#method.checked_pow) - [`num::NonZero*::saturating_mul`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroUsize.html#method.saturating_mul) - [`num::NonZero*::saturating_pow`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroUsize.html#method.saturating_pow) - [`num::NonZeroI*::abs`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroIsize.html#method.abs) - [`num::NonZeroI*::checked_abs`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroIsize.html#method.checked_abs) - [`num::NonZeroI*::overflowing_abs`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroIsize.html#method.overflowing_abs) - [`num::NonZeroI*::saturating_abs`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroIsize.html#method.saturating_abs) - [`num::NonZeroI*::unsigned_abs`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroIsize.html#method.unsigned_abs) - [`num::NonZeroI*::wrapping_abs`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroIsize.html#method.wrapping_abs) - [`num::NonZeroU*::checked_add`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroUsize.html#method.checked_add) - [`num::NonZeroU*::checked_next_power_of_two`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroUsize.html#method.checked_next_power_of_two) - [`num::NonZeroU*::saturating_add`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroUsize.html#method.saturating_add) - [`os::unix::process::CommandExt::process_group`] (https://doc.rust-lang.org/stable/std/os/unix/process/trait.CommandExt.html#tymethod.process_group) - [`os::windows::fs::FileTypeExt::is_symlink_dir`] (https://doc.rust-lang.org/stable/std/os/windows/fs/trait.FileTypeExt.html#tymethod.is_symlink_dir) - [`os::windows::fs::FileTypeExt::is_symlink_file`] (https://doc.rust-lang.org/stable/std/os/windows/fs/trait.FileTypeExt.html#tymethod.is_symlink_file) These types were previously stable in `std::ffi`, but are now also available in `core` and `alloc`: - [`core::ffi::CStr`] (https://doc.rust-lang.org/stable/core/ffi/struct.CStr.html) - [`core::ffi::FromBytesWithNulError`] (https://doc.rust-lang.org/stable/core/ffi/struct.FromBytesWithNulError.html) - [`alloc::ffi::CString`] (https://doc.rust-lang.org/stable/alloc/ffi/struct.CString.html) - [`alloc::ffi::FromVecWithNulError`] (https://doc.rust-lang.org/stable/alloc/ffi/struct.FromVecWithNulError.html) - [`alloc::ffi::IntoStringError`] (https://doc.rust-lang.org/stable/alloc/ffi/struct.IntoStringError.html) - [`alloc::ffi::NulError`] (https://doc.rust-lang.org/stable/alloc/ffi/struct.NulError.html) These types were previously stable in `std::os::raw`, but are now also available in `core::ffi` and `std::ffi`: - [`ffi::c_char`] (https://doc.rust-lang.org/stable/std/ffi/type.c_char.html) - [`ffi::c_double`] (https://doc.rust-lang.org/stable/std/ffi/type.c_double.html) - [`ffi::c_float`] (https://doc.rust-lang.org/stable/std/ffi/type.c_float.html) - [`ffi::c_int`] (https://doc.rust-lang.org/stable/std/ffi/type.c_int.html) - [`ffi::c_long`] (https://doc.rust-lang.org/stable/std/ffi/type.c_long.html) - [`ffi::c_longlong`] (https://doc.rust-lang.org/stable/std/ffi/type.c_longlong.html) - [`ffi::c_schar`] (https://doc.rust-lang.org/stable/std/ffi/type.c_schar.html) - [`ffi::c_short`] (https://doc.rust-lang.org/stable/std/ffi/type.c_short.html) - [`ffi::c_uchar`] (https://doc.rust-lang.org/stable/std/ffi/type.c_uchar.html) - [`ffi::c_uint`] (https://doc.rust-lang.org/stable/std/ffi/type.c_uint.html) - [`ffi::c_ulong`] (https://doc.rust-lang.org/stable/std/ffi/type.c_ulong.html) - [`ffi::c_ulonglong`] (https://doc.rust-lang.org/stable/std/ffi/type.c_ulonglong.html) - [`ffi::c_ushort`] (https://doc.rust-lang.org/stable/std/ffi/type.c_ushort.html) These APIs are now usable in const contexts: - [`slice::from_raw_parts`] (https://doc.rust-lang.org/stable/core/slice/fn.from_raw_parts.html) Cargo ----- - [Packages can now inherit settings from the workspace so that the settings can be centralized in one place.] (rust-lang/cargo#10859) See [`workspace.package`](https://doc.rust-lang.org/nightly/cargo/reference/workspaces.html#the-workspacepackage-table) and [`workspace.dependencies`](https://doc.rust-lang.org/nightly/cargo/reference/workspaces.html#the-workspacedependencies-table) for more details on how to define these common settings. - [Cargo commands can now accept multiple `--target` flags to build for multiple targets at once] (rust-lang/cargo#10766), and the [`build.target`](https://doc.rust-lang.org/nightly/cargo/reference/config.html#buildtarget) config option may now take an array of multiple targets. - [The `--jobs` argument can now take a negative number to count backwards from the max CPUs.] (rust-lang/cargo#10844) - [`cargo add` will now update `Cargo.lock`.] (rust-lang/cargo#10902) - [Added](rust-lang/cargo#10838) the [`--crate-type`](https://doc.rust-lang.org/nightly/cargo/commands/cargo-rustc.html#option-cargo-rustc---crate-type) flag to `cargo rustc` to override the crate type. - [Significantly improved the performance fetching git dependencies from GitHub when using a hash in the `rev` field.] (rust-lang/cargo#10079) Misc ---- - [The `rust-analyzer` rustup component is now available on the stable channel.] (rust-lang/rust#98640) Compatibility Notes ------------------- - The minimum required versions for all `-linux-gnu` targets are now at least kernel 3.2 and glibc 2.17, for targets that previously supported older versions: [Increase the minimum linux-gnu versions](rust-lang/rust#95026) - [Network primitives are now implemented with the ideal Rust layout, not the C system layout] (rust-lang/rust#78802). This can cause problems when transmuting the types. - [Add assertion that `transmute_copy`'s `U` is not larger than `T`] (rust-lang/rust#98839) - [A soundness bug in `BTreeMap` was fixed] (rust-lang/rust#99413) that allowed data it was borrowing to be dropped before the container. - [The Drop behavior of C-like enums cast to ints has changed] (rust-lang/rust#96862). These are already discouraged by a compiler warning. - [Relate late-bound closure lifetimes to parent fn in NLL] (rust-lang/rust#98835) - [Errors at const-eval time are now in future incompatibility reports] (rust-lang/rust#97743) - On the `thumbv6m-none-eabi` target, some incorrect `asm!` statements were erroneously accepted if they used the high registers (r8 to r14) as an input/output operand. [This is no longer accepted] (rust-lang/rust#99155). - [`impl Trait` was accidentally accepted as the associated type value of return-position `impl Trait`] (rust-lang/rust#97346), without fulfilling all the trait bounds of that associated type, as long as the hidden type satisfies said bounds. This has been fixed. 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. - Windows builds now use profile-guided optimization, providing 10-20% improvements to compiler performance: [Utilize PGO for windows x64 rustc dist builds] (rust-lang/rust#96978) - [Stop keeping metadata in memory before writing it to disk] (rust-lang/rust#96544) - [compiletest: strip debuginfo by default for mode=ui] (rust-lang/rust#98140) - Many improvements to generated code for derives, including performance improvements: - [Don't use match-destructuring for derived ops on structs.] (rust-lang/rust#98446) - [Many small deriving cleanups] (rust-lang/rust#98741) - [More derive output improvements] (rust-lang/rust#98758) - [Clarify deriving code](rust-lang/rust#98915) - [Final derive output improvements] (rust-lang/rust#99046) - [Stop injecting `#[allow(unused_qualifications)]` in generated `derive` implementations](rust-lang/rust#99485) - [Improve `derive(Debug)`](rust-lang/rust#98190) - [Bump to clap 3](rust-lang/rust#98213) - [fully move dropck to mir](rust-lang/rust#98641) - [Optimize `Vec::insert` for the case where `index == len`.] (rust-lang/rust#98755) - [Convert rust-analyzer to an in-tree tool] (rust-lang/rust#99603)

rustbot added T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. T-libs Relevant to the library team, which will review and decide on the PR/issue. labels Jun 17, 2022

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nnethercote force-pushed the optimize-derive-Debug-code branch from 196abcb to b949e0e Compare June 21, 2022 07:42

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nnethercote and others added 3 commits June 23, 2022 11:10

Rename some ExtCtxt methods.

7586e79

The new names are more accurate. Co-authored-by: Scott McMurray <scottmcm@users.noreply.github.com>

Rewrite TyKind::fmt.

20f0cda

The handwritten versions more compact and easier to read than the derived version.

nnethercote force-pushed the optimize-derive-Debug-code branch from 7ff867e to 20f0cda Compare June 24, 2022 00:24

nnethercote changed the title ~~Optimize the code produced by derive(Debug).~~ Improve derive(Debug) Jun 24, 2022

This was referenced Jun 24, 2022

[Experiment] [WIP] Add clone_from to clone derive #98445

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Don't use match-destructuring for derived ops on structs. #98446

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bors added the merged-by-bors This PR was explicitly merged by bors. label Jun 26, 2022

bors merged commit 788dded into rust-lang:master Jun 26, 2022

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bors mentioned this pull request Jun 26, 2022

Add MAX_UTF{8, 16}_LEN constants #98198

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nnethercote deleted the optimize-derive-Debug-code branch June 26, 2022 21:08

nnethercote mentioned this pull request Jun 26, 2022

Improve some deriving code and add a test #98376

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scottmcm mentioned this pull request Feb 27, 2023

Derive PartialOrd by calling tuple's version #108515

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Improve `derive(Debug)` #98190

Improve `derive(Debug)` #98190

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hudson-ayers commented Jul 14, 2022

Improve derive(Debug) #98190

Improve derive(Debug) #98190

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Improve `derive(Debug)` #98190

Improve `derive(Debug)` #98190