Enable LTO for rustc_driver.so #101403

bjorn3 · 2022-09-04T09:27:35Z

Alternative to #97154

This enables LTO'ing dylibs behind a feature flag and uses this feature for compiling rustc_driver.so.

rust-highfive · 2022-09-04T09:27:38Z

r? @oli-obk

(rust-highfive has picked a reviewer for you, use r? to override)

bjorn3 · 2022-09-04T09:28:25Z

@bors try @rust-timer queue

rust-timer · 2022-09-04T09:28:26Z

Awaiting bors try build completion.

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

bors · 2022-09-04T09:28:34Z

⌛ Trying commit d3365e41c4520a61804dbf8bdc1501523b90b7ad with merge af5e9125d450e00077d4680e4e02685ba33e9f8e...

bors · 2022-09-04T11:01:59Z

☀️ Try build successful - checks-actions
Build commit: af5e9125d450e00077d4680e4e02685ba33e9f8e (af5e9125d450e00077d4680e4e02685ba33e9f8e)

rust-timer · 2022-09-04T11:02:00Z

Queued af5e9125d450e00077d4680e4e02685ba33e9f8e with parent c2d140b, future comparison URL.

rust-timer · 2022-09-04T21:48:49Z

Finished benchmarking commit (af5e9125d450e00077d4680e4e02685ba33e9f8e): comparison URL.

Overall result: ✅ improvements - no action needed

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.

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

Instruction count

This is a highly reliable metric that was used to determine the overall result at the top of this comment.

	mean¹	range	count²
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-4.7%	[-10.5%, -0.5%]	227
Improvements ✅ (secondary)	-4.3%	[-10.6%, -0.6%]	259
All ❌✅ (primary)	-4.7%	[-10.5%, -0.5%]	227

Max RSS (memory usage)

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean¹	range	count²
Regressions ❌ (primary)	2.9%	[1.0%, 5.1%]	27
Regressions ❌ (secondary)	3.3%	[0.9%, 11.7%]	169
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-4.1%	[-5.9%, -2.3%]	2
All ❌✅ (primary)	2.9%	[1.0%, 5.1%]	27

Cycles

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean¹	range	count²
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-4.9%	[-10.3%, -2.1%]	177
Improvements ✅ (secondary)	-5.3%	[-15.7%, -2.3%]	177
All ❌✅ (primary)	-4.9%	[-10.3%, -2.1%]	177

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

bjorn3 · 2022-09-05T09:59:55Z

This will need to add a check that the dependency formats match for all crate types. Otherwise LTO might think it needs to link in a crate at LTO time when compiling, but one of the crate types would link in a dylib containing the crate, giving duplicate symbols, or the other way around.

oli-obk · 2022-09-06T10:41:10Z

cc @Kobzol

Kobzol · 2022-09-06T10:43:17Z

We have actually been discussing this with bjorn3 😅 But thanks!

Kobzol · 2022-09-29T13:48:48Z

Regarding the perf. results:

-3 to -11% wall-time reductions on primary benchmarks, without a single regression (!) and similar results for instruction counts and cycles. This is an incredible result. As an example, it improves diesel walltime by around -10%.
1% reduction in bootstrap time.
Sadly there are some Max-RSS regressions. It's mostly around 5% for helloworld and similar small secondary crates. The primary crates have smaller regressions, up to 2%.

Overall, I think that it's a great result. The RSS hit is unfortunate, but I think that it's worth it to take it for ~5-10% improvement on real world crates. Using LTO could also remedy some of the issues with small functions not being inlined and requiring manual #[inline] sprinkling.

It remains to be seen if there will be some problems with it. One thing that comes to mind is whether LTO won't make perf. swings more common (i.e. modifying a small part of code could produce large perf. changes because of LTO instability), but we have to test that in real usage I suppose.

Also I wonder if we should print some warning or bail completely for now if LTO for dylibs is used outside of rustc. We should also maybe add some configuration option (like rust.lto), only enable it for Linux x64 builds and check it in the bootstrap compilation code, since we haven't tested it anywhere else and currently LTO is being applied unconditionally for stage 2 builds.

Kobzol · 2022-09-29T18:39:48Z

r? @Mark-Simulacrum

This PR implements LTO for the librustc_driver dylib. It's usage is currently only intended for this specific dylib, therefore it requires -Zunstable-options because of its experimental status. A new config entry rust.lto was added, which controls whether the LTO will be enabled. Currently it is enabled for x64 Linux dist CI builds. My previous comment discusses the perf results.

bors · 2022-10-23T15:00:34Z

⌛ Testing commit 565b7e0 with merge 1ca6777...

bors · 2022-10-23T18:10:45Z

☀️ Test successful - checks-actions
Approved by: Mark-Simulacrum
Pushing 1ca6777 to master...

rust-timer · 2022-10-23T20:06:19Z

Finished benchmarking commit (1ca6777): comparison URL.

Overall result: ✅ improvements - no action needed

@rustbot label: -perf-regression

Instruction count

This is a highly reliable metric that was used to determine the overall result at the top of this comment.

	mean¹	range	count²
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-4.2%	[-9.6%, -0.4%]	230
Improvements ✅ (secondary)	-4.0%	[-9.5%, -0.4%]	257
All ❌✅ (primary)	-4.2%	[-9.6%, -0.4%]	230

Max RSS (memory usage)

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean¹	range	count²
Regressions ❌ (primary)	1.7%	[0.4%, 3.1%]	27
Regressions ❌ (secondary)	3.2%	[2.1%, 5.4%]	8
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	1.7%	[0.4%, 3.1%]	27

Cycles

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean¹	range	count²
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-4.7%	[-10.3%, -1.8%]	182
Improvements ✅ (secondary)	-5.1%	[-10.9%, -2.2%]	191
All ❌✅ (primary)	-4.7%	[-10.3%, -1.8%]	182

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

RalfJung · 2022-10-25T18:01:01Z

Looks like this possibly caused #103538

Enable ThinLTO for rustc on x64 msvc This applies the great work from `@bjorn3` and `@Kobzol` in rust-lang#101403 to x64 msvc. Here are the local results for the try build `68c5c85ed759334a11f0b0e586f5032a23f85ce4`, compared to its parent `0a6b941df354c59b546ec4c0d27f2b9b0cb1162c`. Looking better than my previous local builds. ![image](https://user-images.githubusercontent.com/247183/198158039-98ebac0e-da0e-462e-8162-95e88345edb9.png) (I can't show cycle counts, as that option is failing on the windows version of the perf collector, but I'll try to analyze and debug this soon) This will be the first of a few tests for rustc / llvm / both ThinLTO on the windows and mac targets.

Enable ThinLTO for rustc on x64 msvc This applies the great work from `@bjorn3` and `@Kobzol` in rust-lang/rust#101403 to x64 msvc. Here are the local results for the try build `68c5c85ed759334a11f0b0e586f5032a23f85ce4`, compared to its parent `0a6b941df354c59b546ec4c0d27f2b9b0cb1162c`. Looking better than my previous local builds. ![image](https://user-images.githubusercontent.com/247183/198158039-98ebac0e-da0e-462e-8162-95e88345edb9.png) (I can't show cycle counts, as that option is failing on the windows version of the perf collector, but I'll try to analyze and debug this soon) This will be the first of a few tests for rustc / llvm / both ThinLTO on the windows and mac targets.

Perform a bunch of pkglint cleanup while here, and bump bootstrap kits to 1.65.0. Version 1.66.0 (2022-12-15) ========================== Language -------- - [Permit specifying explicit discriminants on all `repr(Int)` enums](rust-lang/rust#95710) ```rust #[repr(u8)] enum Foo { A(u8) = 0, B(i8) = 1, C(bool) = 42, } ``` - [Allow transmutes between the same type differing only in lifetimes](rust-lang/rust#101520) - [Change constant evaluation errors from a deny-by-default lint to a hard error](rust-lang/rust#102091) - [Trigger `must_use` on `impl Trait` for supertraits](rust-lang/rust#102287) This makes `impl ExactSizeIterator` respect the existing `#[must_use]` annotation on `Iterator`. - [Allow `..X` and `..=X` in patterns](rust-lang/rust#102275) - [Uplift `clippy::for_loops_over_fallibles` lint into rustc](rust-lang/rust#99696) - [Stabilize `sym` operands in inline assembly](rust-lang/rust#103168) - [Update to Unicode 15](rust-lang/rust#101912) - [Opaque types no longer imply lifetime bounds](rust-lang/rust#95474) This is a soundness fix which may break code that was erroneously relying on this behavior. Compiler -------- - [Add armv5te-none-eabi and thumbv5te-none-eabi tier 3 targets](rust-lang/rust#101329) - Refer to Rust's [platform support page][platform-support-doc] for more information on Rust's tiered platform support. - [Add support for linking against macOS universal libraries](rust-lang/rust#98736) Libraries --------- - [Fix `#[derive(Default)]` on a generic `#[default]` enum adding unnecessary `Default` bounds](rust-lang/rust#101040) - [Update to Unicode 15](rust-lang/rust#101821) Stabilized APIs --------------- - [`proc_macro::Span::source_text`](https://doc.rust-lang.org/stable/proc_macro/struct.Span.html#method.source_text) - [`uX::{checked_add_signed, overflowing_add_signed, saturating_add_signed, wrapping_add_signed}`](https://doc.rust-lang.org/stable/std/primitive.u8.html#method.checked_add_signed) - [`iX::{checked_add_unsigned, overflowing_add_unsigned, saturating_add_unsigned, wrapping_add_unsigned}`](https://doc.rust-lang.org/stable/std/primitive.i8.html#method.checked_add_unsigned) - [`iX::{checked_sub_unsigned, overflowing_sub_unsigned, saturating_sub_unsigned, wrapping_sub_unsigned}`](https://doc.rust-lang.org/stable/std/primitive.i8.html#method.checked_sub_unsigned) - [`BTreeSet::{first, last, pop_first, pop_last}`](https://doc.rust-lang.org/stable/std/collections/struct.BTreeSet.html#method.first) - [`BTreeMap::{first_key_value, last_key_value, first_entry, last_entry, pop_first, pop_last}`](https://doc.rust-lang.org/stable/std/collections/struct.BTreeMap.html#method.first_key_value) - [Add `AsFd` implementations for stdio lock types on WASI.](rust-lang/rust#101768) - [`impl TryFrom<Vec<T>> for Box<[T; N]>`](https://doc.rust-lang.org/stable/std/boxed/struct.Box.html#impl-TryFrom%3CVec%3CT%2C%20Global%3E%3E-for-Box%3C%5BT%3B%20N%5D%2C%20Global%3E) - [`core::hint::black_box`](https://doc.rust-lang.org/stable/std/hint/fn.black_box.html) - [`Duration::try_from_secs_{f32,f64}`](https://doc.rust-lang.org/stable/std/time/struct.Duration.html#method.try_from_secs_f32) - [`Option::unzip`](https://doc.rust-lang.org/stable/std/option/enum.Option.html#method.unzip) - [`std::os::fd`](https://doc.rust-lang.org/stable/std/os/fd/index.html) Rustdoc ------- - [Add Rustdoc warning for invalid HTML tags in the documentation](rust-lang/rust#101720) Cargo ----- - [Added `cargo remove` to remove dependencies from Cargo.toml](https://doc.rust-lang.org/nightly/cargo/commands/cargo-remove.html) - [`cargo publish` now waits for the new version to be downloadable before exiting](rust-lang/cargo#11062) See [detailed release notes](https://github.com/rust-lang/cargo/blob/master/CHANGELOG.md#cargo-166-2022-12-15) for more. Compatibility Notes ------------------- - [Only apply `ProceduralMasquerade` hack to older versions of `rental`](rust-lang/rust#94063) - [Don't export `__heap_base` and `__data_end` on wasm32-wasi.](rust-lang/rust#102385) - [Don't export `__wasm_init_memory` on WebAssembly.](rust-lang/rust#102426) - [Only export `__tls_*` on wasm32-unknown-unknown.](rust-lang/rust#102440) - [Don't link to `libresolv` in libstd on Darwin](rust-lang/rust#102766) - [Update libstd's libc to 0.2.135 (to make `libstd` no longer pull in `libiconv.dylib` on Darwin)](rust-lang/rust#103277) - [Opaque types no longer imply lifetime bounds](rust-lang/rust#95474) This is a soundness fix which may break code that was erroneously relying on this behavior. - [Make `order_dependent_trait_objects` show up in future-breakage reports](rust-lang/rust#102635) - [Change std::process::Command spawning to default to inheriting the parent's signal mask](rust-lang/rust#101077) 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. - [Enable BOLT for LLVM compilation](rust-lang/rust#94381) - [Enable LTO for rustc_driver.so](rust-lang/rust#101403)

Pkgsrc changes: * pkglint cleanups, bump bootstrap kits to 1.65.0. * New target: mipsel-unknown-netbsd, for cpu=mips32 with soft-float. * Managed to retain the build of aarch64_be, llvm needed a patch to avoid use of neon instructions in the BE case (llvm doesn't support use of neon in BE mode). Ref. patch to src/llvm-project/llvm/lib/Support/BLAKE3/blake3_impl.h. Also submitted upstream of LLVM to the BLAKE3 maintainers. * The minimum gcc version is now 7.x, and that includes the cross-compiler for the targets. For i386 this also needs to /usr/include/gcc-7 include files in the target root, because immintrin.h from gcc 5 is not compatible with gcc 7.x. This applies for the targets where we build against a root from netbsd-8 (sparc64, powerpc, i386), and files/gcc-wrap gets a hack for this. * Pick up tweak for -latomic inclusion from rust-lang/rust#104220 and rust-lang/rust#104572 * Retain ability to do 32-bit NetBSD, by changing from 64 to 32 bit types in library/std/src/sys/unix/thread_parker/netbsd.rs. * I've tried to get the "openssl-src" build with -latomic where it's needed. I've introduced the "NetBSD-generic32" system type and use it for the NetBSD mipsel target. There is another attempt to do the same in the patch to vendor/openssl-sys/build/main.rs. Upstream changes: Version 1.66.1 (2023-01-10) =========================== - Added validation of SSH host keys for git URLs in Cargo ([CVE-2022-46176](https://www.cve.org/CVERecord?id=CVE-2022-46176)) Version 1.66.0 (2022-12-15) =========================== Language -------- - [Permit specifying explicit discriminants on all `repr(Int)` enums](rust-lang/rust#95710) ```rust #[repr(u8)] enum Foo { A(u8) = 0, B(i8) = 1, C(bool) = 42, } ``` - [Allow transmutes between the same type differing only in lifetimes](rust-lang/rust#101520) - [Change constant evaluation errors from a deny-by-default lint to a hard error](rust-lang/rust#102091) - [Trigger `must_use` on `impl Trait` for supertraits](rust-lang/rust#102287) This makes `impl ExactSizeIterator` respect the existing `#[must_use]` annotation on `Iterator`. - [Allow `..X` and `..=X` in patterns](rust-lang/rust#102275) - [Uplift `clippy::for_loops_over_fallibles` lint into rustc](rust-lang/rust#99696) - [Stabilize `sym` operands in inline assembly](rust-lang/rust#103168) - [Update to Unicode 15](rust-lang/rust#101912) - [Opaque types no longer imply lifetime bounds](rust-lang/rust#95474) This is a soundness fix which may break code that was erroneously relying on this behavior. Compiler -------- - [Add armv5te-none-eabi and thumbv5te-none-eabi tier 3 targets](rust-lang/rust#101329) - Refer to Rust's [platform support page][platform-support-doc] for more information on Rust's tiered platform support. - [Add support for linking against macOS universal libraries](rust-lang/rust#98736) Libraries --------- - [Fix `#[derive(Default)]` on a generic `#[default]` enum adding unnecessary `Default` bounds](rust-lang/rust#101040) - [Update to Unicode 15](rust-lang/rust#101821) Stabilized APIs --------------- - [`proc_macro::Span::source_text`](https://doc.rust-lang.org/stable/proc_macro/struct.Span.html#method.source_text) - [`uX::{checked_add_signed, overflowing_add_signed, saturating_add_signed, wrapping_add_signed}`](https://doc.rust-lang.org/stable/std/primitive.u8.html#method.checked_add_signed) - [`iX::{checked_add_unsigned, overflowing_add_unsigned, saturating_add_unsigned, wrapping_add_unsigned}`](https://doc.rust-lang.org/stable/std/primitive.i8.html#method.checked_add_unsigned) - [`iX::{checked_sub_unsigned, overflowing_sub_unsigned, saturating_sub_unsigned, wrapping_sub_unsigned}`](https://doc.rust-lang.org/stable/std/primitive.i8.html#method.checked_sub_unsigned) - [`BTreeSet::{first, last, pop_first, pop_last}`](https://doc.rust-lang.org/stable/std/collections/struct.BTreeSet.html#method.first) - [`BTreeMap::{first_key_value, last_key_value, first_entry, last_entry, pop_first, pop_last}`](https://doc.rust-lang.org/stable/std/collections/struct.BTreeMap.html#method.first_key_value) - [Add `AsFd` implementations for stdio lock types on WASI.](rust-lang/rust#101768) - [`impl TryFrom<Vec<T>> for Box<[T; N]>`](https://doc.rust-lang.org/stable/std/boxed/struct.Box.html#impl-TryFrom%3CVec%3CT%2C%20Global%3E%3E-for-Box%3C%5BT%3B%20N%5D%2C%20Global%3E) - [`core::hint::black_box`](https://doc.rust-lang.org/stable/std/hint/fn.black_box.html) - [`Duration::try_from_secs_{f32,f64}`](https://doc.rust-lang.org/stable/std/time/struct.Duration.html#method.try_from_secs_f32) - [`Option::unzip`](https://doc.rust-lang.org/stable/std/option/enum.Option.html#method.unzip) - [`std::os::fd`](https://doc.rust-lang.org/stable/std/os/fd/index.html) Rustdoc ------- - [Add Rustdoc warning for invalid HTML tags in the documentation](rust-lang/rust#101720) Cargo ----- - [Added `cargo remove` to remove dependencies from Cargo.toml](https://doc.rust-lang.org/nightly/cargo/commands/cargo-remove.html) - [`cargo publish` now waits for the new version to be downloadable before exiting](rust-lang/cargo#11062) See [detailed release notes](https://github.com/rust-lang/cargo/blob/master/CHANGELOG.md#cargo-166-2022-12-15) for more. Compatibility Notes ------------------- - [Only apply `ProceduralMasquerade` hack to older versions of `rental`](rust-lang/rust#94063) - [Don't export `__heap_base` and `__data_end` on wasm32-wasi.](rust-lang/rust#102385) - [Don't export `__wasm_init_memory` on WebAssembly.](rust-lang/rust#102426) - [Only export `__tls_*` on wasm32-unknown-unknown.](rust-lang/rust#102440) - [Don't link to `libresolv` in libstd on Darwin](rust-lang/rust#102766) - [Update libstd's libc to 0.2.135 (to make `libstd` no longer pull in `libiconv.dylib` on Darwin)](rust-lang/rust#103277) - [Opaque types no longer imply lifetime bounds](rust-lang/rust#95474) This is a soundness fix which may break code that was erroneously relying on this behavior. - [Make `order_dependent_trait_objects` show up in future-breakage reports](rust-lang/rust#102635) - [Change std::process::Command spawning to default to inheriting the parent's signal mask](rust-lang/rust#101077) 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. - [Enable BOLT for LLVM compilation](rust-lang/rust#94381) - [Enable LTO for rustc_driver.so](rust-lang/rust#101403) Version 1.65.0 (2022-11-03) ========================== Language -------- - [Error on `as` casts of enums with `#[non_exhaustive]` variants] (rust-lang/rust#92744) - [Stabilize `let else`](rust-lang/rust#93628) - [Stabilize generic associated types (GATs)] (rust-lang/rust#96709) - [Add lints `let_underscore_drop`, `let_underscore_lock`, and `let_underscore_must_use` from Clippy] (rust-lang/rust#97739) - [Stabilize `break`ing from arbitrary labeled blocks ("label-break-value")] (rust-lang/rust#99332) - [Uninitialized integers, floats, and raw pointers are now considered immediate UB](rust-lang/rust#98919). Usage of `MaybeUninit` is the correct way to work with uninitialized memory. - [Stabilize raw-dylib for Windows x86_64, aarch64, and thumbv7a] (rust-lang/rust#99916) - [Do not allow `Drop` impl on foreign ADTs] (rust-lang/rust#99576) Compiler -------- - [Stabilize -Csplit-debuginfo on Linux] (rust-lang/rust#98051) - [Use niche-filling optimization even when multiple variants have data] (rust-lang/rust#94075) - [Associated type projections are now verified to be well-formed prior to resolving the underlying type] (rust-lang/rust#99217) - [Stringify non-shorthand visibility correctly] (rust-lang/rust#100350) - [Normalize struct field types when unsizing] (rust-lang/rust#101831) - [Update to LLVM 15](rust-lang/rust#99464) - [Fix aarch64 call abi to correctly zeroext when needed] (rust-lang/rust#97800) - [debuginfo: Generalize C++-like encoding for enums] (rust-lang/rust#98393) - [Add `special_module_name` lint] (rust-lang/rust#94467) - [Add support for generating unique profraw files by default when using `-C instrument-coverage`] (rust-lang/rust#100384) - [Allow dynamic linking for iOS/tvOS targets] (rust-lang/rust#100636) New targets: - [Add armv4t-none-eabi as a tier 3 target] (rust-lang/rust#100244) - [Add powerpc64-unknown-openbsd and riscv64-unknown-openbsd as tier 3 targets] (rust-lang/rust#101025) - Refer to Rust's [platform support page][platform-support-doc] for more information on Rust's tiered platform support. Libraries --------- - [Don't generate `PartialEq::ne` in derive(PartialEq)] (rust-lang/rust#98655) - [Windows RNG: Use `BCRYPT_RNG_ALG_HANDLE` by default] (rust-lang/rust#101325) - [Forbid mixing `System` with direct system allocator calls] (rust-lang/rust#101394) - [Document no support for writing to non-blocking stdio/stderr] (rust-lang/rust#101416) - [`std::layout::Layout` size must not overflow `isize::MAX` when rounded up to `align`](rust-lang/rust#95295) This also changes the safety conditions on `Layout::from_size_align_unchecked`. Stabilized APIs --------------- - [`std::backtrace::Backtrace`] (https://doc.rust-lang.org/stable/std/backtrace/struct.Backtrace.html) - [`Bound::as_ref`] (https://doc.rust-lang.org/stable/std/ops/enum.Bound.html#method.as_ref) - [`std::io::read_to_string`] (https://doc.rust-lang.org/stable/std/io/fn.read_to_string.html) - [`<*const T>::cast_mut`] (https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.cast_mut) - [`<*mut T>::cast_const`] (https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.cast_const) These APIs are now stable in const contexts: - [`<*const T>::offset_from`] (https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.offset_from) - [`<*mut T>::offset_from`] (https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.offset_from) Cargo ----- - [Apply GitHub fast path even for partial hashes] (rust-lang/cargo#10807) - [Do not add home bin path to PATH if it's already there] (rust-lang/cargo#11023) - [Take priority into account within the pending queue] (rust-lang/cargo#11032). This slightly optimizes job scheduling by Cargo, with typically small improvements on larger crate graph builds. Compatibility Notes ------------------- - [`std::layout::Layout` size must not overflow `isize::MAX` when rounded up to `align`] (rust-lang/rust#95295). This also changes the safety conditions on `Layout::from_size_align_unchecked`. - [`PollFn` now only implements `Unpin` if the closure is `Unpin`] (rust-lang/rust#102737). This is a possible breaking change if users were relying on the blanket unpin implementation. See discussion on the PR for details of why this change was made. - [Drop ExactSizeIterator impl from std::char::EscapeAscii] (rust-lang/rust#99880) This is a backwards-incompatible change to the standard library's surface area, but is unlikely to affect real world usage. - [Do not consider a single repeated lifetime eligible for elision in the return type] (rust-lang/rust#103450) This behavior was unintentionally changed in 1.64.0, and this release reverts that change by making this an error again. - [Reenable disabled early syntax gates as future-incompatibility lints] (rust-lang/rust#99935) - [Update the minimum external LLVM to 13] (rust-lang/rust#100460) - [Don't duplicate file descriptors into stdio fds] (rust-lang/rust#101426) - [Sunset RLS](rust-lang/rust#100863) - [Deny usage of `#![cfg_attr(..., crate_type = ...)]` to set the crate type] (rust-lang/rust#99784) This strengthens the forward compatibility lint deprecated_cfg_attr_crate_type_name to deny. - [`llvm-has-rust-patches` allows setting the build system to treat the LLVM as having Rust-specific patches] (rust-lang/rust#101072) This option may need to be set for distributions that are building Rust with a patched LLVM via `llvm-config`, not the built-in LLVM. 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 `x.sh` and `x.ps1` shell scripts] (rust-lang/rust#99992) - [compiletest: use target cfg instead of hard-coded tables] (rust-lang/rust#100260) - [Use object instead of LLVM for reading bitcode from rlibs] (rust-lang/rust#98100) - [Enable MIR inlining for optimized compilations] (rust-lang/rust#91743) This provides a 3-10% improvement in compiletimes for real world crates. See [perf results] (https://perf.rust-lang.org/compare.html?start=aedf78e56b2279cc869962feac5153b6ba7001ed&end=0075bb4fad68e64b6d1be06bf2db366c30bc75e1&stat=instructions:u).

Enable ThinLTO for rustc on x64 msvc This applies the great work from `@bjorn3` and `@Kobzol` in rust-lang/rust#101403 to x64 msvc. Here are the local results for the try build `68c5c85ed759334a11f0b0e586f5032a23f85ce4`, compared to its parent `0a6b941df354c59b546ec4c0d27f2b9b0cb1162c`. Looking better than my previous local builds. ![image](https://user-images.githubusercontent.com/247183/198158039-98ebac0e-da0e-462e-8162-95e88345edb9.png) (I can't show cycle counts, as that option is failing on the windows version of the perf collector, but I'll try to analyze and debug this soon) This will be the first of a few tests for rustc / llvm / both ThinLTO on the windows and mac targets.

rust-highfive assigned oli-obk Sep 4, 2022

rustbot added T-bootstrap Relevant to the bootstrap subteam: Rust's build system (x.py and src/bootstrap) T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels Sep 4, 2022

rust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Sep 4, 2022

rustbot added the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Sep 4, 2022

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bjorn3 mentioned this pull request Sep 4, 2022

[WIP] Use static linking for compiling rustc in CI #97154

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rustbot removed the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Sep 4, 2022

Kobzol mentioned this pull request Sep 7, 2022

Use linker plugin LTO for compiling rustc #101524

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bjorn3 force-pushed the dylib_lto branch from d3365e4 to 88b7c40 Compare September 29, 2022 13:49

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rustbot added the T-infra Relevant to the infrastructure team, which will review and decide on the PR/issue. label Sep 29, 2022

bors added the S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. label Oct 23, 2022

bors added the merged-by-bors This PR was explicitly merged by bors. label Oct 23, 2022

bors merged commit 1ca6777 into rust-lang:master Oct 23, 2022

rustbot added this to the 1.66.0 milestone Oct 23, 2022

bors mentioned this pull request Oct 23, 2022

Support #[global_allocator] without the allocator shim #86844

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bjorn3 deleted the dylib_lto branch October 23, 2022 18:40

bors mentioned this pull request Oct 23, 2022

Port pgo.sh to Python #103019

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Mark-Simulacrum mentioned this pull request Oct 25, 2022

rustc-dev component recently became a lot bigger #103538

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nnethercote mentioned this pull request Oct 26, 2022

Tracking issue for speeding up rustc via its build configuration #103595

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23 tasks

lqd mentioned this pull request Oct 26, 2022

Enable ThinLTO for rustc on x64 msvc #103591

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This was referenced Dec 13, 2022

Missing ICE info after some compiler panics #105637

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Temporarily disable building rustc with ThinLTO on x86_64-unknown-linux-gnu and x86_64-pc-windows-msvc #105662

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tmandry mentioned this pull request Apr 21, 2023

ICE: assertion failed: ptr::eq(context.tcx.gcx as *const _ as *const (), tcx.gcx as *const _ as *const ()), compiler/rustc_middle/src/ty/context/tls.rs #110564

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bjorn3 mentioned this pull request May 26, 2023

Allow linking against dylibs in LTO mode #31854

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bjorn3 mentioned this pull request Jul 13, 2023

Linking dylib with "lto = true": assertion failed: !is_full_lto_enabled(sess) #50324

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Enable LTO for rustc_driver.so #101403

Enable LTO for rustc_driver.so #101403

bjorn3 commented Sep 4, 2022 •

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RalfJung commented Oct 25, 2022

Enable LTO for rustc_driver.so #101403

Enable LTO for rustc_driver.so #101403

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bjorn3 commented Sep 4, 2022 • edited Loading

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rust-timer commented Sep 4, 2022

Overall result: ✅ improvements - no action needed

Instruction count

Max RSS (memory usage)

Cycles

Footnotes

bjorn3 commented Sep 5, 2022

oli-obk commented Sep 6, 2022

Kobzol commented Sep 6, 2022

Kobzol commented Sep 29, 2022

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bors commented Oct 23, 2022

bors commented Oct 23, 2022

rust-timer commented Oct 23, 2022

Overall result: ✅ improvements - no action needed

Instruction count

Max RSS (memory usage)

Cycles

Footnotes

RalfJung commented Oct 25, 2022

bjorn3 commented Sep 4, 2022 •

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