Deprecate no-op codegen option `-Cinline-threshold=...` #124712

Enselic · 2024-05-04T15:27:31Z

This deprecates -Cinline-threshold since using it has no effect. This has been the case since the new LLVM pass manager started being used, more than 2 years ago.

Recommend using -Cllvm-args=--inline-threshold=... instead.

Closes #89742 which is E-help-wanted.

rustbot · 2024-05-04T15:27:39Z

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workingjubilee · 2024-05-04T19:35:54Z

compiler/rustc_session/src/options.rs

@@ -1502,7 +1502,8 @@ options! {
    incremental: Option<String> = (None, parse_opt_string, [UNTRACKED],
        "enable incremental compilation"),
    inline_threshold: Option<u32> = (None, parse_opt_number, [TRACKED],
-        "set the threshold for inlining a function"),
+        "this option is deprecated and does nothing \
+        (consider using `-Cllvm-args=--inline-threshold=...`)"),


Will this have any effect if they do?

Yes that makes a difference. Building e.g. libstd with -Cllvm-args=--inline-threshold=100000 vs -Cllvm-args=--inline-threshold=2 reliably makes a big difference in the size of .text, namely 1594 kB vs 367 kB:

$ RUSTFLAGS="-Ccodegen-units=1 -Cllvm-args=--inline-threshold=100000" ./x build --stage 0 library/std $ size ./build/x86_64-unknown-linux-gnu/stage0-std/x86_64-unknown-linux-gnu/release/libstd.rlib text ... 0 ... 1594437 ... $ RUSTFLAGS="-Ccodegen-units=1 -Cllvm-args=--inline-threshold=2" ./x build --stage 0 library/std $ size ./build/x86_64-unknown-linux-gnu/stage0-std/x86_64-unknown-linux-gnu/release/libstd.rlib text ... 0 ... 367682 ...

Another example is bat with 33 MB vs 5.4 MB:

$ RUSTFLAGS="-Cllvm-args=--inline-threshold=2" cargo build --release $ ls -hl target/release/bat -rwxr-xr-x 2 martin martin 5.4M May 5 10:58 target/release/bat $ RUSTFLAGS="-Cllvm-args=--inline-threshold=100000" cargo build --release $ ls -hl target/release/bat -rwxr-xr-x 2 martin martin 33M May 5 11:13 target/release/bat

Oh neat, I'm surprised it does anything!

ehuss · 2024-06-03T15:27:10Z

r? compiler

fmease

The GH issue had a fair bit of discussion and ppl seemed to have mostly settled on deprecation + warning. While you've obviously taken the NOP (+ doc) approach, emitting a warning or remapping it to -C llvm-args=-inline-threshold= are still valid options.

Emitting a warning would've likely prevented the odyssey as reported in #89742 (comment). Not a fan of non-lint warnings (i.e., ones that cannot be suppressed) but I think it would make perfect sense here. -Cno-stack-check emits a warning for example (-Car=... doesn't OTOH).

Regarding remapping to LLVM's "new"(?) inline-threshold I'm not well-versed enough in the matter to be able to give any input on that. Apart from semantic differences compared to the OldPM days (which seems to be the case having read the discussion), I guess another factor are the guarantees we (want to) provide for -C* flags esp. wrt. alternative codegen backends (codegen_{cranelift,gcc} are still unstable ofc). I don't know anything about that, so I'll let sb. else take a look at this PR.

fmease · 2024-06-13T09:04:46Z

I'm pretty sure this needs a compiler FCP, therefore:
r? compiler-team

fmease · 2024-06-13T09:21:29Z

compiler/rustc_session/src/options.rs

@@ -1502,7 +1502,8 @@ options! {
    incremental: Option<String> = (None, parse_opt_string, [UNTRACKED],
        "enable incremental compilation"),
    inline_threshold: Option<u32> = (None, parse_opt_number, [TRACKED],


TL;DR: If the deprecation ends up getting accepted (rather than the remapping), please emit a warning like -Cno-stack-check does (and unlike -Car=... which we might want to change in a separate PR).

Done, including regression test.

Note that I also added this commit to this PR:

commit 651ff643ae68438213bded335ef47cc9c50d3039 Author: Martin Nordholts <martin.nordholts@codetale.se> Date: Fri Jun 14 19:48:40 2024 +0200 Fix typo in `-Cno-stack-check` deprecation warning The flag `--no-stack-check` does not exist: $ rustc --no-stack-check error: Unrecognized option: 'no-stack-check'. Did you mean `-C no-stack-check`?

Enselic · 2024-06-14T04:19:26Z

remapping it to -C llvm-args=-inline-threshold=

Remapping would probably have been good in late 2021 instead of making -Cinline-threshold a no-op. If we do it now - almost three years later - it would arguable be just as surprising as when it stopped working.

Also, maintaining the mapping will be quite much work. There are several knobs in LLVM to tweak, and people will have opinions on how to do it. I foresee endless discussions on how we should do it exactly. And this problem is multiplied for each codegen backend. So given where we are today, I think it is best to not try to remap.

But emitting a warning like -Cno-stack-check does is a good idea. I will do that. Thanks for taking a look at my PR!

The flag `--no-stack-check` does not exist: $ rustc --no-stack-check error: Unrecognized option: 'no-stack-check'. Did you mean `-C no-stack-check`?

This deprecates `-Cinline-threshold` since using it has no effect. This has been the case since the new LLVM pass manager started being used, more than 2 years ago.

pnkfelix · 2024-06-24T14:03:44Z

i think our official process when it comes to changing the stable command line interface of rustc is the Major Change Proposal (MCP) process.

But this specific change strikes me largely as a bug fix where the PR author is trying to make the whole thing more coherent (while also making the actual change quite minimal), and I don't think it warrants an MCP.

So, I'm going to r+ (because I don't think we need to further delay landing this change), but I also am going to nominate this PR so that the T-compiler team can double-check whether I am right that there exists some CLI changes that do not warrant an MCP.

@bors r+

bors · 2024-06-24T14:03:47Z

📌 Commit f5f067b has been approved by pnkfelix

It is now in the queue for this repository.

pnkfelix · 2024-06-24T14:05:44Z

(as an example of why I nominated this, the T-compiler team might want to discuss the valid feedback left by @fmease , in order to determine whether an MCP was in fact warranted here.)

…mpiler-errors Rollup of 11 pull requests Successful merges: - rust-lang#124460 (Show notice about "never used" of Debug for enum) - rust-lang#124712 (Deprecate no-op codegen option `-Cinline-threshold=...`) - rust-lang#125082 (Remove `MaybeUninit::uninit_array()` and replace it with inline const blocks.) - rust-lang#125575 (SmartPointer derive-macro) - rust-lang#126413 (compiletest: make the crash test error message abit more informative) - rust-lang#126673 (Ensure we don't accidentally succeed when we want to report an error) - rust-lang#126682 (coverage: Overhaul validation of the `#[coverage(..)]` attribute) - rust-lang#126899 (Suggest inline const blocks for array initialization) - rust-lang#126904 (Small fixme in core now that NonZero is generic) - rust-lang#126909 (add `@kobzol` to bootstrap team for triagebot) - rust-lang#126911 (Split the lifetimes of `MirBorrowckCtxt`) r? `@ghost` `@rustbot` modify labels: rollup

Rollup merge of rust-lang#124712 - Enselic:deprecate-inline-threshold, r=pnkfelix Deprecate no-op codegen option `-Cinline-threshold=...` This deprecates `-Cinline-threshold` since using it has no effect. This has been the case since the new LLVM pass manager started being used, more than 2 years ago. Recommend using `-Cllvm-args=--inline-threshold=...` instead. Closes rust-lang#89742 which is E-help-wanted.

It doesn't work anyway, see rust-lang/rust#124712

See rust-lang#124712 for details.

It doesn't work anyway, see rust-lang/rust#124712

@Kobzol

Update Rust toolchain from nightly-2024-06-24 to nightly-2024-06-25 without any other source changes. This is an automatically generated pull request. If any of the CI checks fail, manual intervention is required. In such a case, review the changes at https://github.com/rust-lang/rust from rust-lang@bcf94de up to rust-lang@6b0f4b5. The log for this commit range is: rust-lang@6b0f4b5ec3 Auto merge of rust-lang#126914 - compiler-errors:rollup-zx0hchm, r=compiler-errors rust-lang@16bd6e25e1 Rollup merge of rust-lang#126911 - oli-obk:do_not_count_errors, r=compiler-errors rust-lang@59c258f51f Rollup merge of rust-lang#126909 - onur-ozkan:add-kobzol, r=matthiaskrgr rust-lang@85eb835a14 Rollup merge of rust-lang#126904 - GrigorenkoPV:nonzero-fixme, r=joboet rust-lang@a7721a0373 Rollup merge of rust-lang#126899 - GrigorenkoPV:suggest-const-block, r=davidtwco rust-lang@9ce2a070b3 Rollup merge of rust-lang#126682 - Zalathar:coverage-attr, r=lcnr rust-lang@49bdf460a2 Rollup merge of rust-lang#126673 - oli-obk:dont_rely_on_err_reporting, r=compiler-errors rust-lang@46e43984d1 Rollup merge of rust-lang#126413 - matthiaskrgr:crshmsg, r=oli-obk rust-lang@ed460d2eaa Rollup merge of rust-lang#125575 - dingxiangfei2009:derive-smart-ptr, r=davidtwco rust-lang@c77dc28f87 Rollup merge of rust-lang#125082 - kpreid:const-uninit, r=dtolnay rust-lang@faa28be2f1 Rollup merge of rust-lang#124712 - Enselic:deprecate-inline-threshold, r=pnkfelix rust-lang@00e5f5886a Rollup merge of rust-lang#124460 - long-long-float:show-notice-about-enum-with-debug, r=pnkfelix rust-lang@d8d5732456 Auto merge of rust-lang#126784 - scottmcm:smaller-terminator, r=compiler-errors rust-lang@13fca73f49 Replace `MaybeUninit::uninit_array()` with array repeat expression. rust-lang@5a3e2a4e92 Auto merge of rust-lang#126523 - joboet:the_great_big_tls_refactor, r=Mark-Simulacrum rust-lang@45261ff2ec add @Kobzol to bootstrap team for triagebot rust-lang@84474a25a4 Small fixme in core now that NonZero is generic rust-lang@50a02ed789 std: fix wasm builds rust-lang@8fc6b3de19 Separate the mir body lifetime from the other lifetimes rust-lang@1c4d0ced58 Separate the lifetimes of the `BorrowckInferCtxt` from the other borrowed items rust-lang@d371d17496 Auto merge of rust-lang#126900 - matthiaskrgr:rollup-24ah97b, r=matthiaskrgr rust-lang@8ffb5f936a compiletest: make the crash test error message abit more informative rust-lang@a80ee9159b Rollup merge of rust-lang#126882 - estebank:multiline-order, r=WaffleLapkin rust-lang@8bfde609e2 Rollup merge of rust-lang#126414 - ChrisDenton:target-known, r=Nilstrieb rust-lang@94b9ea417d Rollup merge of rust-lang#126213 - zachs18:atomicbool-u8-i8-from-ptr-alignment, r=Nilstrieb rust-lang@9d24ecc37b Rollup merge of rust-lang#125241 - Veykril:tool-rust-analyzer, r=davidtwco rust-lang@ba5ec1fc5c Suggest inline const blocks for array initialization rust-lang@06c072f158 Auto merge of rust-lang#126788 - GuillaumeGomez:migrate-rustdoc-tests-syntax, r=fmease,oli-obk rust-lang@1852141219 coverage: Bless coverage attribute tests rust-lang@b7c057c9b2 coverage: Always error on `#[coverage(..)]` in unexpected places rust-lang@a000fa8b54 coverage: Tighten validation of `#[coverage(off)]` and `#[coverage(on)]` rust-lang@b5dfeba0e1 coverage: Forbid multiple `#[coverage(..)]` attributes rust-lang@6909feab8e Allow numbers in rustdoc tests commands rust-lang@4e258bb4c3 Fix tidy issue for rustdoc tests commands rust-lang@51fedf65ff Remove commands duplication between `compiletest` and `tests/rustdoc` rust-lang@1b67035579 Update `tests/rustdoc` to new test syntax rust-lang@d3ec92e16e Move `tests/rustdoc` testsuite to `//@` syntax rust-lang@2c243d9570 Auto merge of rust-lang#126891 - matthiaskrgr:rollup-p6dl1gk, r=matthiaskrgr rust-lang@b94d2754b5 Rollup merge of rust-lang#126888 - compiler-errors:oops-debug-printing, r=dtolnay rust-lang@9892b3e9fe Rollup merge of rust-lang#126854 - devnexen:std_unix_os_fallback_upd, r=Mark-Simulacrum rust-lang@3108dfaced Rollup merge of rust-lang#126849 - workingjubilee:correctly-classify-arm-low-dregs, r=Amanieu rust-lang@dcace866f0 Rollup merge of rust-lang#126845 - rust-lang:cargo_update, r=Mark-Simulacrum rust-lang@21850f5bd8 Rollup merge of rust-lang#126807 - devnexen:copy_file_macos_simpl, r=Mark-Simulacrum rust-lang@b24e3df0df Rollup merge of rust-lang#126754 - compiler-errors:use-rustfmt, r=calebcartwright rust-lang@ad0531ae0d Rollup merge of rust-lang#126455 - surechen:fix_126222, r=estebank rust-lang@7babf99ea9 Rollup merge of rust-lang#126298 - heiher:loongarch64-musl-ci, r=Mark-Simulacrum rust-lang@9a591ea1ce Rollup merge of rust-lang#126177 - carbotaniuman:unsafe_attr_errors, r=jieyouxu rust-lang@25446c25fc Remove stray println from rustfmt rust-lang@d49994b060 Auto merge of rust-lang#126023 - amandasystems:you-dropped-this-again, r=nikomatsakis rust-lang@a23917cfd0 Add hard error and migration lint for unsafe attrs rust-lang@284437d434 Special case when a code line only has multiline span starts rust-lang@f1be59fa72 SmartPointer derive-macro rust-lang@a426d6fdf0 Implement use<> formatting in rustfmt rust-lang@16fef40896 Promote loongarch64-unknown-linux-musl to Tier 2 with host tools rust-lang@03d73fa6ba ci: Add support for dist-loongarch64-musl rust-lang@fc50acae90 fix build rust-lang@bd9ce3e074 std::unix::os::home_dir: fallback's optimisation. rust-lang@0d8f734172 compiler: Fix arm32 asm issues by hierarchically sorting reg classes rust-lang@e8b5ba1111 For [E0308]: mismatched types, when expr is in an arm's body, not add semicolon ';' at the end of it. rust-lang@990535723d cargo update rust-lang@b28efb11af Save 2 pointers in `TerminatorKind` (96 → 80 bytes) rust-lang@65530ba100 std::unix::fs: copy simplification for apple. rust-lang@339015920d Add `rust_analyzer` as a predefined tool rust-lang@3f2f8438b4 Ensure we don't accidentally succeed when we want to report an error rust-lang@32f9b8bf76 std: rename module for clarity rust-lang@35f050b8da std: update TLS module documentation rust-lang@b2f29edc81 std: use the `c_int` from `core::ffi` instead of `libc` rust-lang@d70f071392 std: simplify `#[cfg]`s for TLS rust-lang@d630f5da7a Show notice about "never used" for enum rust-lang@f3facf1175 std: refactor the TLS implementation rust-lang@f5f067bf9d Deprecate no-op codegen option `-Cinline-threshold=...` rust-lang@651ff643ae Fix typo in `-Cno-stack-check` deprecation warning rust-lang@3af624272a rustc_codegen_ssa: Remove unused ModuleConfig::inline_threshold rust-lang@34e6ea1446 Tier 2 std support must always be known rust-lang@2d4cb7aa5a Update docs for AtomicU8/I8. rust-lang@7885c7b7b2 Update safety docs for AtomicBool::from_ptr. rust-lang@7b5b7a7010 Remove confusing `use_polonius` flag and do less cloning Co-authored-by: tautschnig <1144736+tautschnig@users.noreply.github.com>

rustbot assigned JohnTitor May 4, 2024

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rustc_codegen_ssa: Remove unused ModuleConfig::inline_threshold

3af6242

Enselic force-pushed the deprecate-inline-threshold branch from be39c26 to 97c67ee Compare June 14, 2024 18:18

Enselic changed the title ~~Deprecate codegen option inline-threshold~~ Deprecate no-op codegen option -Cinline-threshold=... Jun 14, 2024

Enselic added 2 commits June 14, 2024 20:21

Fix typo in -Cno-stack-check deprecation warning

651ff64

The flag `--no-stack-check` does not exist: $ rustc --no-stack-check error: Unrecognized option: 'no-stack-check'. Did you mean `-C no-stack-check`?

Deprecate no-op codegen option -Cinline-threshold=...

f5f067b

This deprecates `-Cinline-threshold` since using it has no effect. This has been the case since the new LLVM pass manager started being used, more than 2 years ago.

Enselic force-pushed the deprecate-inline-threshold branch from 97c67ee to f5f067b Compare June 14, 2024 18:26

bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Jun 24, 2024

pnkfelix added the I-compiler-nominated The issue / PR has been nominated for discussion during a compiler team meeting. label Jun 24, 2024

compiler-errors mentioned this pull request Jun 24, 2024

Rollup of 11 pull requests #126914

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bors merged commit faa28be into rust-lang:master Jun 24, 2024
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rustbot added this to the 1.81.0 milestone Jun 24, 2024

hudson-ayers mentioned this pull request Jul 16, 2024

Migrate build to be entirely cargo-based, with make as integration tool tock/tock#4075

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jannic added a commit to jannic/rp-hal that referenced this pull request Jul 26, 2024

Remove -Cinline-threshold=5 option from config.toml

003eb36

It doesn't work anyway, see rust-lang/rust#124712

jannic mentioned this pull request Jul 26, 2024

Remove -Cinline-threshold=5 option from config.toml rp-rs/rp-hal#822

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jannic added a commit to jannic/rust that referenced this pull request Jul 26, 2024

Mark the inline-threshold option as deprecated and non-functional

845540a

See rust-lang#124712 for details.

jannic added a commit to jannic/rust that referenced this pull request Jul 26, 2024

Mark the inline-threshold option as deprecated and non-functional

45cd793

See rust-lang#124712 for details.

jannic mentioned this pull request Jul 26, 2024

Mark the inline-threshold option as deprecated and non-functional #128238

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jannic added a commit to jannic/rp2040-project-template that referenced this pull request Jul 26, 2024

Remove -C inline-threshold=5 option from config.toml

17706c2

It doesn't work anyway, see rust-lang/rust#124712

jannic mentioned this pull request Jul 26, 2024

Remove -C inline-threshold=5 option from config.toml rp-rs/rp2040-project-template#79

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9names pushed a commit to rp-rs/rp2040-project-template that referenced this pull request Jul 26, 2024

Remove -C inline-threshold=5 option from config.toml (#79)

8f7b4b6

It doesn't work anyway, see rust-lang/rust#124712

9names pushed a commit to rp-rs/rp-hal that referenced this pull request Jul 26, 2024

Remove -Cinline-threshold=5 option from config.toml (#822)

956668e

It doesn't work anyway, see rust-lang/rust#124712

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Deprecate no-op codegen option `-Cinline-threshold=...` #124712

Deprecate no-op codegen option `-Cinline-threshold=...` #124712

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Deprecate no-op codegen option -Cinline-threshold=... #124712

Deprecate no-op codegen option -Cinline-threshold=... #124712

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Deprecate no-op codegen option `-Cinline-threshold=...` #124712

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