T Compiler Meeting Agenda 2024 09 05

T-compiler Meeting Agenda 2024-09-05

Announcements

Other WG meetings

MCPs/FCPs

  • New MCPs (take a look, see if you like them!)
  • Old MCPs (stale MCP might be closed as per MCP procedure)
    • None at this time
  • Old MCPs (not seconded, take a look)
  • Pending FCP requests (check your boxes!)
    • “sanitizers: Stabilize AddressSanitizer and LeakSanitizer for the Tier 1 targets” rust#123617
    • “Add --print host-triple to print host target triple” rust#125579
  • Things in FCP (make sure you’re good with it)
  • Accepted MCPs
    • No new accepted proposals this time.
  • MCPs blocked on unresolved concerns
  • Finalized FCPs (disposition merge)
    • None
  • Other teams finalized FCPs
    • “rustdoc: add header map to the table of contents” rust#120736
    • “doc: Make block of inline Deref methods foldable” rust#127474

WG checkins

None

Backport nominations

T-compiler beta / T-compiler stable

  • No beta nominations for T-compiler this time.
  • No stable nominations for T-compiler this time.

T-types stable / T-types beta

  • No beta nominations for T-types this time.
  • No stable nominations for T-types this time.

PRs S-waiting-on-team

T-compiler

  • “Stabilize extended_varargs_abi_support” rust#116161
  • “Better errors with bad/missing identifiers in MBEs” rust#118939
  • “Uplift clippy::invalid_null_ptr_usage lint” rust#119220
  • “Rename AsyncIterator back to Stream, introduce an AFIT-based AsyncIterator trait” rust#119550
  • “Disallow deriving (other than Copy/Clone) on types with unnamed fields” rust#121270
  • “Emit a warning if a match is too complex” rust#122685
  • “Add Unicode block-drawing compiler output support” rust#126597
  • “Emit error when calling/declaring functions with vectors that require missing target feature” rust#127731
  • “[crater] Make missing_fragment_specifier an unconditional error” rust#128425
  • “repr(int) fieldless enums are ABI-compatible with int” rust#128600
  • “optimize attribute applied to things other than methods/functions/c…” rust#128943
  • “Gate repr(Rust) correctly on non-ADT items” rust#129422
  • Issues in progress or waiting on other teams

Issues of Note

Short Summary

P-critical

T-compiler

  • None

T-types

  • No P-critical issues for T-types this time.

P-high regressions

P-high beta regressions

Unassigned P-high nightly regressions

  • No unassigned P-high nightly regressions this time.

Performance logs

triage logs for 2024-09-03

This week we had some trouble with our performance bot, but luckily the issue has been resolved. In the end, we saw much more improvements than regressions.

Triage done by @kobzol. Revision range: acb4e8b6..6199b69c

Summary:

(instructions:u) mean range count
Regressions ❌ (primary) 0.3% [0.2%, 0.4%] 8
Regressions ❌ (secondary) 0.7% [0.2%, 1.5%] 9
Improvements ✅ (primary) -0.8% [-3.4%, -0.2%] 158
Improvements ✅ (secondary) -0.7% [-2.3%, -0.2%] 96
All ❌✅ (primary) -0.7% [-3.4%, 0.4%] 166

2 Regressions, 3 Improvements, 1 Mixed; 3 of them in rollups 19 artifact comparisons made in total

Regressions

Rollup of 7 pull requests #129750 (Comparison Link)

(instructions:u) mean range count
Regressions ❌ (primary) 0.4% [0.3%, 0.5%] 7
Regressions ❌ (secondary) 6.0% [6.0%, 6.0%] 1
Improvements ✅ (primary) - - 0
Improvements ✅ (secondary) - - 0
All ❌✅ (primary) 0.4% [0.3%, 0.5%] 7
  • This was bimodal noise.

Rollup of 8 pull requests #129922 (Comparison Link)

(instructions:u) mean range count
Regressions ❌ (primary) - - 0
Regressions ❌ (secondary) 5.8% [5.8%, 5.8%] 1
Improvements ✅ (primary) - - 0
Improvements ✅ (secondary) - - 0
All ❌✅ (primary) - - 0
  • Likely the same story, just with a different benchmark.
  • Not marking as triaged yet.

Improvements

Rollup of 15 pull requests #129809 (Comparison Link)

(instructions:u) mean range count
Regressions ❌ (primary) - - 0
Regressions ❌ (secondary) - - 0
Improvements ✅ (primary) -0.3% [-0.9%, -0.2%] 21
Improvements ✅ (secondary) -0.7% [-5.9%, -0.1%] 18
All ❌✅ (primary) -0.3% [-0.9%, -0.2%] 21

Revert “Auto merge of #127537 - veluca93:struct_tf, r=BoxyUwU” #129854 (Comparison Link)

(instructions:u) mean range count
Regressions ❌ (primary) - - 0
Regressions ❌ (secondary) - - 0
Improvements ✅ (primary) -0.4% [-1.1%, -0.2%] 81
Improvements ✅ (secondary) -0.5% [-2.2%, -0.2%] 24
All ❌✅ (primary) -0.4% [-1.1%, -0.2%] 81
  • Revert of an earlier PR that had larger than expected regressions.
  • Investigation is ongoing on how to land it without such large regressions.

Apply size optimizations to panic machinery and some cold functions #129063 (Comparison Link)

(instructions:u) mean range count
Regressions ❌ (primary) 0.2% [0.2%, 0.2%] 2
Regressions ❌ (secondary) - - 0
Improvements ✅ (primary) -1.2% [-3.0%, -0.3%] 16
Improvements ✅ (secondary) -1.0% [-1.5%, -0.4%] 4
All ❌✅ (primary) -1.0% [-3.0%, 0.2%] 18

Mixed

Rewrite lint_expectations in a single pass. #127313 (Comparison Link)

(instructions:u) mean range count
Regressions ❌ (primary) 0.4% [0.3%, 0.4%] 9
Regressions ❌ (secondary) 0.6% [0.2%, 1.5%] 14
Improvements ✅ (primary) -0.5% [-1.5%, -0.2%] 82
Improvements ✅ (secondary) -0.7% [-1.8%, -0.1%] 58
All ❌✅ (primary) -0.4% [-1.5%, 0.4%] 91
  • More improvements than regressions, marking as triaged.

Nominated Issues

T-compiler

  • “Tracking peak total storage use” rust#129808
    • nominated by @Jubilee
    • Context: last week our CI started to fail due to not having enough storage available
    • Questions for all teams:
      • Are we aware of past efforts being aware of whether or not we have reduced the size?
      • What information is [t-compiler] currently tracking re: size?
      • What information would [t-compiler] like to have available re: size?
  • “Add Unicode block-drawing compiler output support” rust#126597
    • Proposal from @Esteban Küber
    • Nominated by @León Orell Liehr (fmease) (assigned reviewer), asks if this proposal would benefit from some sort of agreement from T-compiler (MCP or other)
    • More context here and here

RFC

  • No I-compiler-nominated RFCs this time.

Oldest PRs waiting for review

T-compiler

  • “fix: get llvm type of global val” rust#128820 (last review activity: about 21 days ago)
    • cc @Nikita Popov
  • “Implement a lint for implicit autoref of raw pointer dereference - take 2” rust#123239
    • cc: @León Orell Liehr (fmease)
  • “Apply EarlyOtherwiseBranch to scalar value” rust#129047 (last review activity: about 22 days ago)
    • cc: @cjgillot

Next week’s WG checkins

None

Next meetings' agenda draft: hackmd link