Skip to content

Externally implementable items #146348

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom
Open
jdonszelmann wants to merge 22 commits into
base: main
Choose a base branch
from
Open

Externally implementable items #146348

jdonszelmann wants to merge 22 commits into from
+3,428 −65

Conversation

@jdonszelmann
Copy link
Contributor

@jdonszelmann jdonszelmann commented Sep 8, 2025 •
edited
Loading

Supersedes #140010
Tracking issue: #125418

Getting started:

#![feature(eii)]

#[eii(eii1)]
pub fn decl1(x: u64) 
// body optional (it's the default)
{
    println!("default {x}");
}

// in another crate, maybe
#[eii1]
pub fn decl2(x: u64) {
    println!("explicit {x}");
}

fn main() {
    decl1(4);
}
  • tiny perf regression, underlying issue makes multiple things in the compiler slow, not just EII, planning to solve those separately.
  • No codegen_gcc support, they don't have bindings for weak symbols yet but could
  • No windows support yet for weak definitions

This PR merges the implementation of EII for just llvm + not windows, doesn't yet contain like a new panic handler implementation or alloc handler. With this implementation, it would support implementing the panic handler in terms of EII already since it requires no default implementation so no weak symbols

The PR has been open in various forms for about a year now, but I feel that having some implementation merged to build upon

@rustbot rustbot added A-attributes Area: Attributes (`#[…]`, `#![…]`) A-LLVM Area: Code generation parts specific to LLVM. Both correctness bugs and optimization-related issues. S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. T-clippy Relevant to the Clippy team. 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 Sep 8, 2025
@rust-log-analyzer

This comment has been minimized.

Sign in to view
jdonszelmann
jdonszelmann commented Sep 8, 2025
View reviewed changes
jdonszelmann
jdonszelmann commented Sep 8, 2025
View reviewed changes
@rust-log-analyzer

This comment has been minimized.

Sign in to view
@rust-log-analyzer

This comment has been minimized.

Sign in to view
@rust-log-analyzer

This comment has been minimized.

Sign in to view
@rust-log-analyzer

This comment has been minimized.

Sign in to view
@jdonszelmann
Copy link
Contributor Author

jdonszelmann commented Sep 9, 2025

@bors2 try @rust-timer queue

@rust-timer

This comment has been minimized.

Sign in to view
@rust-bors

This comment has been minimized.

Sign in to view
rust-bors bot added a commit that referenced this pull request Sep 9, 2025
@rust-bors
Auto merge of #146348 - jdonszelmann:eiiv3, r=<try>
d5a6633 
[DONT MERGE] externally implementable items
@rustbot rustbot added the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Sep 9, 2025
@rust-bors
Copy link

rust-bors bot commented Sep 9, 2025

☀️ Try build successful (CI)
Build commit: d5a6633 (d5a66337e06d3b77a1ab8f6793055535195c3ae9, parent: 364da5d88d772fa40fb20353443595385443ac25)

@rust-timer

This comment has been minimized.

Sign in to view
@rust-timer
Copy link
Collaborator

rust-timer commented Sep 9, 2025

Finished benchmarking commit (d5a6633): comparison URL.

Overall result: ❌ regressions - please read the text below

Benchmarking this pull request means it may be perf-sensitive – we'll automatically label it not fit for rolling up. You can override this, but we strongly advise not to, due to possible changes in compiler perf.

Next Steps: If you can justify the regressions found in this try perf run, please do so in sufficient writing along with @rustbot label: +perf-regression-triaged. If not, please fix the regressions and do another perf run. If its results are neutral or positive, the label will be automatically removed.

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

Instruction count

Our most reliable metric. Used to determine the overall result above. However, even this metric can be noisy.

mean range count
Regressions ❌
(primary)		 0.3% [0.1%, 1.5%] 19
Regressions ❌
(secondary)		 0.4% [0.1%, 1.0%] 44
Improvements ✅
(primary)		 - - 0
Improvements ✅
(secondary)		 -0.0% [-0.1%, -0.0%] 4
All ❌✅ (primary) 0.3% [0.1%, 1.5%] 19

Max RSS (memory usage)

Results (primary 1.7%, secondary 3.9%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

mean range count
Regressions ❌
(primary)		 1.7% [0.6%, 2.3%] 6
Regressions ❌
(secondary)		 4.7% [1.1%, 11.2%] 16
Improvements ✅
(primary)		 - - 0
Improvements ✅
(secondary)		 -2.1% [-2.9%, -1.2%] 2
All ❌✅ (primary) 1.7% [0.6%, 2.3%] 6

Cycles

Results (primary 3.1%, secondary -1.3%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

mean range count
Regressions ❌
(primary)		 3.1% [3.1%, 3.1%] 1
Regressions ❌
(secondary)		 3.2% [2.5%, 3.6%] 3
Improvements ✅
(primary)		 - - 0
Improvements ✅
(secondary)		 -2.8% [-4.1%, -2.0%] 9
All ❌✅ (primary) 3.1% [3.1%, 3.1%] 1

Binary size

Results (primary 0.0%, secondary 0.1%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

mean range count
Regressions ❌
(primary)		 0.0% [0.0%, 0.1%] 93
Regressions ❌
(secondary)		 0.1% [0.0%, 0.3%] 61
Improvements ✅
(primary)		 - - 0
Improvements ✅
(secondary)		 - - 0
All ❌✅ (primary) 0.0% [0.0%, 0.1%] 93

Bootstrap: 468.052s -> 471.14s (0.66%)
Artifact size: 387.52 MiB -> 390.25 MiB (0.71%)

@rustbot rustbot added perf-regression Performance regression. and removed S-waiting-on-perf Status: Waiting on a perf run to be completed. labels Sep 9, 2025
@jdonszelmann
Copy link
Contributor Author

jdonszelmann commented Sep 10, 2025

Well, shit. I think I know some fixes but I hoped this wouldn't happen

jdonszelmann
jdonszelmann commented Sep 10, 2025
View reviewed changes
@rustbot
Copy link
Collaborator

rustbot commented Dec 12, 2025

This PR was rebased onto a different main commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.

lcnr
lcnr reviewed Dec 12, 2025
View reviewed changes
lcnr
lcnr reviewed Dec 12, 2025
View reviewed changes
lcnr
lcnr reviewed Dec 12, 2025
View reviewed changes
Copy link
Contributor

@lcnr lcnr left a comment •
edited by rustbot
Loading

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

r=me after nits :3

View changes since this review

@jdonszelmann jdonszelmann force-pushed the eiiv3 branch 2 times, most recently from e78dd1b to aafb44f Compare December 12, 2025 11:08
@lcnr lcnr mentioned this pull request Dec 12, 2025
Open
@jdonszelmann
Copy link
Contributor Author

jdonszelmann commented Dec 12, 2025

@bors r=lcnr,oli-obk

@bors
Copy link
Collaborator

bors commented Dec 12, 2025

📌 Commit e7b729c has been approved by lcnr,oli-obk

It is now in the queue for this repository.

@bors 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 Dec 12, 2025
bors added a commit that referenced this pull request Dec 12, 2025
@bors
Auto merge of #146348 - jdonszelmann:eiiv3, r=lcnr,oli-obk
4a942cd 
Externally implementable items

Supersedes #140010
Tracking issue: #125418

Getting started:

```rust
#![feature(eii)]

#[eii(eii1)]
pub fn decl1(x: u64)
// body optional (it's the default)
{
    println!("default {x}");
}

// in another crate, maybe
#[eii1]
pub fn decl2(x: u64) {
    println!("explicit {x}");
}

fn main() {
    decl1(4);
}
```

- tiny perf regression, underlying issue makes multiple things in the compiler slow, not just EII, planning to solve those separately.
- No codegen_gcc support, they don't have bindings for weak symbols yet but could
- No windows support yet for weak definitions

This PR merges the implementation of EII for just llvm + not windows, doesn't yet contain like a new panic handler implementation or alloc handler. With this implementation, it would support implementing the panic handler in terms of EII already since it requires no default implementation so no weak symbols

The PR has been open in various forms for about a year now, but I feel that having some implementation merged to build upon
@bors
Copy link
Collaborator

bors commented Dec 12, 2025

⌛ Testing commit e7b729c with merge 4a942cd...

@rust-log-analyzer
Copy link
Collaborator

rust-log-analyzer commented Dec 12, 2025

The job x86_64-mingw-1 failed! Check out the build log: (web) (plain enhanced) (plain)

Click to see the possible cause of the failure (guessed by this bot) 
test [ui] tests\ui\editions\unsafe-attr-edition-span.rs#e2021 ... ok
test [ui] tests\ui\editions\unsafe-attr-edition-span.rs#e2024 ... ok
test [ui] tests\ui\editions\never-type-fallback.rs#e2021 ... ok
test [ui] tests\ui\editions\never-type-fallback.rs#e2024 ... ok
test [ui] tests\ui\eii\cross_crate.rs ... ok
test [ui] tests\ui\eii\cross_crate_wrong_ty.rs ... ok
test [ui] tests\ui\eii\codegen_single_crate.rs ... ok
test [ui] tests\ui\eii\codegen_cross_crate.rs ... ok
test [ui] tests\ui\eii\default\call_default.rs ... FAILED
test [ui] tests\ui\eii\default\local_crate.rs ... ok
test [ui] tests\ui\eii\default\local_crate_explicit.rs ... ok
test [ui] tests\ui\eii\default\call_impl.rs ... ok
test [ui] tests\ui\eii\errors.rs ... ok
test [ui] tests\ui\eii\multiple_decls.rs ... ok
test [ui] tests\ui\eii\duplicate\duplicate1.rs ... ok
test [ui] tests\ui\eii\duplicate\duplicate2.rs ... ok
test [ui] tests\ui\eii\multiple_impls.rs ... ok
test [ui] tests\ui\eii\privacy1.rs ... ok
test [ui] tests\ui\eii\subtype_1.rs ... ok
test [ui] tests\ui\eii\privacy2.rs ... ok
test [ui] tests\ui\eii\duplicate\duplicate3.rs ... ok
test [ui] tests\ui\eii\subtype_2.rs ... ok
test [ui] tests\ui\eii\subtype_3.rs ... ok
test [ui] tests\ui\eii\subtype_4.rs ... ok
test [ui] tests\ui\eii\unsafe_impl_err.rs ... ok
test [ui] tests\ui\eii\unsafe_impl_ok.rs ... ok
test [ui] tests\ui\eii\wrong_ret_ty.rs ... ok
test [ui] tests\ui\eii\same-symbol.rs ... ok
test [ui] tests\ui\eii\wrong_target.rs ... ok
test [ui] tests\ui\eii\wrong_ty.rs ... ok
test [ui] tests\ui\eii\wrong_ty_2.rs ... ok
test [ui] tests\ui\empty\empty-attributes.rs ... ok
test [ui] tests\ui\empty\empty-comment.rs ... ok
test [ui] tests\ui\empty\empty-linkname.rs ... ok
test [ui] tests\ui\empty\empty-never-array.rs ... ok
test [ui] tests\ui\empty\empty-macro-use.rs ... ok
---
test [ui] tests\ui\zero-sized\zero-sized-btreemap-insert.rs ... ok

failures:

---- [ui] tests\ui\eii\default\call_default.rs stdout ----

error: test compilation failed although it shouldn't!
status: exit code: 1
command: PATH="D:\a\rust\rust\build\x86_64-pc-windows-gnu\stage2\bin;D:\a\rust\rust\build\x86_64-pc-windows-gnu\bootstrap-tools\x86_64-pc-windows-gnu\release\deps;D:\a\rust\rust\ninja;D:\a\rust\rust\mingw64\bin;C:\msys64\usr\bin;D:\a\rust\rust\sccache;C:\Program Files\MongoDB\Server\7.0\bin;C:\vcpkg;C:\tools\zstd;C:\hostedtoolcache\windows\stack\3.7.1\x64;C:\cabal\bin;C:\ghcup\bin;C:\mingw64\bin;C:\Program Files\dotnet;C:\Program Files\MySQL\MySQL Server 8.0\bin;C:\Program Files\R\R-4.5.2\bin\x64;C:\SeleniumWebDrivers\GeckoDriver;C:\SeleniumWebDrivers\EdgeDriver;C:\SeleniumWebDrivers\ChromeDriver;C:\Program Files (x86)\sbt\bin;C:\Program Files (x86)\GitHub CLI;C:\Program Files\Git\bin;C:\Program Files (x86)\pipx_bin;C:\npm\prefix;C:\hostedtoolcache\windows\go\1.24.11\x64\bin;C:\hostedtoolcache\windows\Python\3.9.13\x64\Scripts;C:\hostedtoolcache\windows\Python\3.9.13\x64;C:\hostedtoolcache\windows\Ruby\3.3.10\x64\bin;C:\Program Files\OpenSSL\bin;C:\tools\kotlinc\bin;C:\hostedtoolcache\windows\Java_Temurin-Hotspot_jdk\17.0.17-10\x64\bin;C:\Program Files\ImageMagick-7.1.2-Q16-HDRI;C:\Program Files\Microsoft SDKs\Azure\CLI2\wbin;C:\ProgramData\kind;C:\ProgramData\Chocolatey\bin;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0;C:\Windows\System32\OpenSSH;C:\Program Files\PowerShell\7;C:\Program Files\Microsoft\Web Platform Installer;C:\Program Files\Microsoft SQL Server\Client SDK\ODBC\170\Tools\Binn;C:\Program Files\Microsoft SQL Server\150\Tools\Binn;C:\Program Files\dotnet;C:\Program Files (x86)\Windows Kits\10\Windows Performance Toolkit;C:\Program Files (x86)\WiX Toolset v3.14\bin;C:\Program Files\Microsoft SQL Server\130\DTS\Binn;C:\Program Files\Microsoft SQL Server\140\DTS\Binn;C:\Program Files\Microsoft SQL Server\150\DTS\Binn;C:\Program Files\Microsoft SQL Server\160\DTS\Binn;C:\Program Files\Microsoft SQL Server\170\DTS\Binn;C:\ProgramData\chocolatey\lib\pulumi\tools\Pulumi\bin;C:\Program Files\CMake\bin;C:\Strawberry\c\bin;C:\Strawberry\perl\site\bin;C:\Strawberry\perl\bin;C:\ProgramData\chocolatey\lib\maven\apache-maven-3.9.11\bin;C:\Program Files\Microsoft Service Fabric\bin\Fabric\Fabric.Code;C:\Program Files\Microsoft SDKs\Service Fabric\Tools\ServiceFabricLocalClusterManager;C:\Program Files\nodejs;C:\Program Files\Git\cmd;C:\Program Files\Git\mingw64\bin;C:\Program Files\Git\usr\bin;C:\Program Files\GitHub CLI;C:\tools\php;C:\Program Files (x86)\sbt\bin;C:\Program Files\Amazon\AWSCLIV2;C:\Program Files\Amazon\SessionManagerPlugin\bin;C:\Program Files\Amazon\AWSSAMCLI\bin;C:\Program Files\Microsoft SQL Server\130\Tools\Binn;C:\Program Files\mongosh;C:\Program Files\LLVM\bin;C:\Program Files (x86)\LLVM\bin;C:\Users\runneradmin\.dotnet\tools;C:\Users\runneradmin\.cargo\bin;C:\Users\runneradmin\AppData\Local\Microsoft\WindowsApps" "D:\\a\\rust\\rust\\build\\x86_64-pc-windows-gnu\\stage2\\bin\\rustc.exe" "D:\\a\\rust\\rust\\tests\\ui\\eii\\default\\call_default.rs" "-Zthreads=1" "-Zsimulate-remapped-rust-src-base=/rustc/FAKE_PREFIX" "-Ztranslate-remapped-path-to-local-path=no" "-Z" "ignore-directory-in-diagnostics-source-blocks=C:\\Users\\runneradmin\\.cargo" "-Z" "ignore-directory-in-diagnostics-source-blocks=D:\\a\\rust\\rust\\vendor" "--sysroot" "D:\\a\\rust\\rust\\build\\x86_64-pc-windows-gnu\\stage2" "--target=x86_64-pc-windows-gnu" "--check-cfg" "cfg(test,FALSE)" "-O" "--error-format" "json" "--json" "future-incompat" "-Ccodegen-units=1" "-Zui-testing" "-Zdeduplicate-diagnostics=no" "-Zwrite-long-types-to-disk=no" "-Cstrip=debuginfo" "-o" "D:\\a\\rust\\rust\\build\\x86_64-pc-windows-gnu\\test\\ui\\eii\\default\\call_default\\a.exe" "-A" "internal_features" "-A" "unused_parens" "-A" "unused_braces" "-Crpath" "-Cdebuginfo=0" "-Lnative=D:\\a\\rust\\rust\\build\\x86_64-pc-windows-gnu\\native\\rust-test-helpers" "-L" "D:\\a\\rust\\rust\\build\\x86_64-pc-windows-gnu\\test\\ui\\eii\\default\\call_default\\auxiliary"
stdout: none
--- stderr -------------------------------
error: linking with `x86_64-w64-mingw32-gcc` failed: exit code: 1
   |
   = note: "x86_64-w64-mingw32-gcc" "-fno-use-linker-plugin" "-Wl,--dynamicbase" "-Wl,--disable-auto-image-base" "-m64" "-Wl,--high-entropy-va" "C:\\Users\\RUNNER~1\\AppData\\Local\\Temp\\rustcI7Jwb4\\symbols.o" "<2 object files omitted>" "-Wl,-Bstatic" "D:\\a\\rust\\rust\\build\\x86_64-pc-windows-gnu\\test\\ui\\eii\\default\\call_default\\auxiliary/libdecl_with_default.rlib" "<sysroot>\\lib\\rustlib\\x86_64-pc-windows-gnu\\lib/{libstd-*,libpanic_unwind-*,libobject-*,libmemchr-*,libaddr2line-*,libgimli-*,libcfg_if-*,libwindows_targets-*,librustc_demangle-*,libstd_detect-*,libhashbrown-*,librustc_std_workspace_alloc-*,libminiz_oxide-*,libadler2-*,libunwind-*,liblibc-*,librustc_std_workspace_core-*,liballoc-*,libcore-*,libcompiler_builtins-*}.rlib" "-Wl,-Bdynamic" "-lkernel32" "-lkernel32" "-lkernel32" "-lntdll" "-luserenv" "-lws2_32" "-ldbghelp" "-lgcc_eh" "-l:libpthread.a" "-lmsvcrt" "-lmingwex" "-lmingw32" "-lgcc" "-lmsvcrt" "-lmingwex" "-luser32" "-lkernel32" "-Wl,--nxcompat" "-L" "D:\\a\\rust\\rust\\build\\x86_64-pc-windows-gnu\\native\\rust-test-helpers" "-L" "D:\\a\\rust\\rust\\build\\x86_64-pc-windows-gnu\\test\\ui\\eii\\default\\call_default\\auxiliary" "-o" "D:\\a\\rust\\rust\\build\\x86_64-pc-windows-gnu\\test\\ui\\eii\\default\\call_default\\a.exe" "-Wl,--gc-sections" "-no-pie" "-Wl,-O1" "-Wl,--strip-debug" "-nodefaultlibs"
   = note: some arguments are omitted. use `--verbose` to show all linker arguments
   = note: D:/a/rust/rust/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/14.1.0/../../../../x86_64-w64-mingw32/bin/ld.exe: D:\a\rust\rust\build\x86_64-pc-windows-gnu\test\ui\eii\default\call_default\a.call_default.e65edcad8a79f346-cgu.0.rcgu.o:call_default.e65edcad8a79f346-cgu.0:(.text+0x86): undefined reference to `decl_with_default::decl1'
           collect2.exe: error: ld returned 1 exit status
           
   = note: some `extern` functions couldn't be found; some native libraries may need to be installed or have their path specified
   = note: use the `-l` flag to specify native libraries to link

error: aborting due to 1 previous error
------------------------------------------

---- [ui] tests\ui\eii\default\call_default.rs stdout end ----

failures:
    [ui] tests\ui\eii\default\call_default.rs

test result: FAILED. 19882 passed; 1 failed; 340 ignored; 0 measured; 21 filtered out; finished in 1329.49s

Some tests failed in compiletest suite=ui mode=ui host=x86_64-pc-windows-gnu target=x86_64-pc-windows-gnu
Bootstrap failed while executing `test --stage 2 --skip=compiler --skip=src`
Build completed unsuccessfully in 1:52:35
make: *** [Makefile:123: ci-mingw-x] Error 1
  local time: Fri Dec 12 18:15:53 CUT 2025
  network time: Fri, 12 Dec 2025 18:15:54 GMT
##[error]Process completed with exit code 2.
##[group]Run echo "disk usage:"
echo "disk usage:"

@bors
Copy link
Collaborator

bors commented Dec 12, 2025

💔 Test failed - checks-actions

@bors bors added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. labels Dec 12, 2025
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Reviewers

@GuillaumeGomez GuillaumeGomez GuillaumeGomez left review comments

@fmease fmease fmease left review comments

@lcnr lcnr lcnr left review comments

@bjorn3 bjorn3 bjorn3 requested changes

@oli-obk oli-obk oli-obk approved these changes

Assignees

@oli-obk oli-obk

@lcnr lcnr

Labels

A-attributes Area: Attributes (`#[…]`, `#![…]`) A-LLVM Area: Code generation parts specific to LLVM. Both correctness bugs and optimization-related issues. perf-regression Performance regression. S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-clippy Relevant to the Clippy team. 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.

Projects

None yet

Milestone

No milestone

Development

Successfully merging this pull request may close these issues.