chore: bump to cc@1.4.3 for rustc_llvm and library by weihanglo · Pull Request #161260 · rust-lang/rust

weihanglo · 2026-08-17T20:08:08Z

What is this?

Old cc-rs derives this from the -Clto rustflag on its own.
cc@1.2.39 starts gating that behind -Clinker-plugin-lto,
which bootstrap doesn't pass.
Therefore,
we need to pass this flag explicitly to keep LTO mode

Previous efforts:

I personally want this because of cc 1.3.0+ has the support of Cargo -Ztrim-paths,
which helps what I am experimenting in #161049.

How to review

Commit by commit.

To keep commits bisect-able,
I added the first commit without cc bump.
clang should be fine with duplicate -flto flags.

One thing I am not certain is whether we should probe -flto flag in this case,
or just make this fail if -flto isn't supported.
(I assume -flto is quote widely supported)

r? Kobzol

🤖 LLM disclosure: I used LLM for the experiment of #161049, but not the bootstrap LTO change in this PR.

rustbot · 2026-08-17T20:08:14Z

Kobzol is not on the review rotation at the moment.
They may take a while to respond.

weihanglo · 2026-08-17T20:09:00Z

@bors try @rust-timer queue

and cc @bjorn3 @Kobzol

chore: bump to cc@1.4.3 for rustc_llvm and library

rust-bors · 2026-08-17T21:07:28Z

☀️ Try build successful (CI)
Build commit: 7256718 (7256718699c6a701d58e50866ab3f86a2ffa8cef)
Base parent: 6d656b1 (6d656b1efca82491a110b476ac9bbe712628ccb6)

rust-timer · 2026-08-17T22:03:54Z

Finished benchmarking commit (7256718): comparison URL.

Overall result: no relevant changes - no action needed

Benchmarking means the PR may be perf-sensitive. Consider adding rollup=never if this change is not fit for rolling up.

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

Instruction count

This perf run didn't have relevant results for this metric.

Max RSS (memory usage)

This perf run didn't have relevant results for this metric.

Cycles

This perf run didn't have relevant results for this metric.

Binary size

This perf run didn't have relevant results for this metric.

Bootstrap: 468.493s -> 459.635s (-1.89%)
Artifact size: 398.93 MiB -> 398.87 MiB (-0.01%)

weihanglo · 2026-08-17T22:57:51Z

@Kobzol od you know why there is no result? I guess because GitHub was down?

weihanglo · 2026-08-17T22:58:03Z

@bors try @rust-timer queue

chore: bump to cc@1.4.3 for rustc_llvm and library

rust-bors · 2026-08-17T23:57:31Z

☀️ Try build successful (CI)
Build commit: 52a6c34 (52a6c343ae344ec730508ef19f1eb62167f1b4ad)
Base parent: e702eca (e702ecae8a3e3756e8a499f8592be1e3efac0e8f)

rust-timer · 2026-08-18T00:54:24Z

Finished benchmarking commit (52a6c34): comparison URL.

Overall result: no relevant changes - no action needed

Benchmarking means the PR may be perf-sensitive. Consider adding rollup=never if this change is not fit for rolling up.

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

Instruction count

This perf run didn't have relevant results for this metric.

Max RSS (memory usage)

Results (secondary 1.6%)

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

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	1.6%	[0.6%, 2.5%]	2
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Cycles

This perf run didn't have relevant results for this metric.

Binary size

Results (primary 0.1%, 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)	0.1%	[0.0%, 0.1%]	75
Regressions ❌ (secondary)	0.1%	[0.0%, 0.1%]	114
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.1%	[0.0%, 0.1%]	75

Bootstrap: 457.751s -> 457.734s (-0.00%)
Artifact size: 398.90 MiB -> 398.92 MiB (0.00%)

weihanglo · 2026-08-18T01:42:31Z

Ah. I see. No relevant largely means insignificant. Then I think this is ready.

@rustbot ready

chore: bump to cc@1.4.3 for rustc_llvm and library ### What is this? Old cc-rs derives this from the `-Clto` rustflag on its own. `cc@1.2.39` starts gating that behind `-Clinker-plugin-lto`, which bootstrap doesn't pass. Therefore, we need to pass this flag explicitly to keep LTO mode Previous efforts: * #146186 * #155438 I personally want this because of cc 1.3.0+ has the support of Cargo `-Ztrim-paths`, which helps what I am experimenting in <#161049>. ### How to review Commit by commit. To keep commits bisect-able, I added the first commit without cc bump. clang should be fine with duplicate `-flto` flags. One thing I am not certain is whether we should probe `-flto` flag in this case, or just make this fail if `-flto` isn't supported. (I assume `-flto` is quote widely supported) r? Kobzol --- 🤖 **LLM disclosure:** I used LLM for the experiment of <#161049>, but not the bootstrap LTO change in this PR.

rust-bors · 2026-08-19T17:05:37Z

💔 Test for ddaaa13 failed: CI. Failed job:

auto - dist-aarch64-linux (web logs, enhanced plaintext logs)

weihanglo · 2026-08-19T19:10:50Z

Oh, no. Still failed.

@rustbot author

weihanglo · 2026-08-19T21:15:22Z

  configure:3111: clang -O3 -ffunction-sections -fdata-sections -fPIC --target=aarch64-unknown-linux-gnu -fprofile-generate=/tmp/tmp-multistage/opt-artifacts/rustc-pgo -fembed-bitcode=all -fdebug-prefix-map=/checkout=/rustc/ddaaa135e3858b8f39f80c8d25184560a6a9fd37 -flto=thin -O3 -ffunction-sections -fdata-sections -fPIC --target=aarch64-unknown-linux-gnu -fprofile-generate=/tmp/tmp-multistage/opt-artifacts/rustc-pgo -fembed-bitcode=all -fdebug-prefix-map=/checkout=/rustc/ddaaa135e3858b8f39f80c8d25184560a6a9fd37 -flto=thin -O3 -ffunction-sections -fdata-sections -fPIC --target=aarch64-unknown-linux-gnu -fprofile-generate=/tmp/tmp-multistage/opt-artifacts/rustc-pgo -fembed-bitcode=all -fdebug-prefix-map=/checkout=/rustc/ddaaa135e3858b8f39f80c8d25184560a6a9fd37 -flto=thin conftest.c  >&5
  /usr/bin/ld: /rustroot/bin/../lib/LLVMgold.so: error loading plugin: /usr/lib64/libstdc++.so.6: version `CXXABI_1.3.11' not found (required by /rustroot/bin/../lib/LLVMgold.so)
  clang: error: linker command failed with exit code 1 (use -v to see invocation)

Did that mean to provide CXXABI_1.3.11 we need some similar hack added in #134690 like this, as the system libstdc++ is outdated?

rust/src/ci/docker/host-x86_64/dist-x86_64-linux/Dockerfile

Lines 115 to 117 in f7d782a

    
           # FIXME: Without this, LLVMgold.so incorrectly resolves to the system 
        
           # libstdc++, instead of the one we build. 
        
           ENV LD_PRELOAD=/rustroot/lib64/libstdc++.so.6

Just like what we did for x86_64 in PR 134690

Old cc-rs derives this from the `-Clto` rustflag on its own. `cc@1.2.39` starts gating that behind `-Clinker-plugin-lto`, which bootstrap doesn't pass. Therefore, we need to pass this flag explicitly to keep LTO mode

Also pulls in * find-msvc-tools 0.1.5 -> 0.1.11 * shlex 2.0.1 (new transitive dep of cc)

Also pulls in * find-msvc-tools 0.1.5 -> 0.1.11 * shlex 1.3.0 -> 2.0.1

weihanglo · 2026-08-20T04:11:26Z

@bors try jobs=dist-aarch64-linux @rust-timer queue

chore: bump to cc@1.4.3 for rustc_llvm and library try-job: dist-aarch64-linux

rust-bors · 2026-08-20T07:43:06Z

☀️ Try build successful (CI)
Build commit: a5859e2 (a5859e2a19c9cca181acab527d5003db8ae6e560)
Base parent: f7d782a (f7d782a3be46d6bb4b9792fe69a61db389ba1769)

rust-timer · 2026-08-20T07:44:09Z

Finished benchmarking commit (a5859e2): comparison URL.

Overall result: no relevant changes - BENCHMARK(S) FAILED

Benchmarking means the PR may be perf-sensitive. Consider adding rollup=never if this change is not fit for rolling up.

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

❗ ❗ ❗ ❗ ❗
Warning ⚠️: The following benchmark(s) failed to build:

Job failure

❗ ❗ ❗ ❗ ❗

Instruction count

This perf run didn't have relevant results for this metric.

Max RSS (memory usage)

This perf run didn't have relevant results for this metric.

Cycles

This perf run didn't have relevant results for this metric.

Binary size

This perf run didn't have relevant results for this metric.

Bootstrap: missing data
Artifact size: missing data

Kobzol · 2026-08-20T07:48:31Z

(The try build didn't contain artifacts for x64, so the perf. run failed).

rustbot assigned Kobzol Aug 17, 2026

This comment has been minimized.

Sign in to view

rustbot added the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Aug 17, 2026

This comment has been minimized.

Sign in to view

rust-bors Bot pushed a commit that referenced this pull request Aug 17, 2026

Auto merge of #161260 - weihanglo:cc-1.4.3, r=<try>

7256718

chore: bump to cc@1.4.3 for rustc_llvm and library

weihanglo mentioned this pull request Aug 17, 2026

Update the cc crate for rustc_llvm #155438

Open

This comment has been minimized.

Sign in to view

rustbot removed the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Aug 17, 2026

This comment has been minimized.

Sign in to view

rustbot added the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Aug 17, 2026

This comment has been minimized.

Sign in to view

rust-bors Bot pushed a commit that referenced this pull request Aug 17, 2026

Auto merge of #161260 - weihanglo:cc-1.4.3, r=<try>

52a6c34

chore: bump to cc@1.4.3 for rustc_llvm and library

This comment has been minimized.

Sign in to view

rustbot removed the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Aug 18, 2026

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Aug 18, 2026

rust-bors Bot 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-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Aug 19, 2026

This comment has been minimized.

Sign in to view

rust-bors Bot 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 Aug 19, 2026

rustbot added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Aug 19, 2026

weihanglo added 4 commits August 20, 2026 00:09

ci(dist-aarch64-linux): preload built libstdc++

2f9f649

Just like what we did for x86_64 in PR 134690

bootstrap: keep rustc C deps with configured LTO mode

0cb5887

Old cc-rs derives this from the `-Clto` rustflag on its own. `cc@1.2.39` starts gating that behind `-Clinker-plugin-lto`, which bootstrap doesn't pass. Therefore, we need to pass this flag explicitly to keep LTO mode

rustc_llvm: bump cc to 1.4.3

6fb7414

Also pulls in * find-msvc-tools 0.1.5 -> 0.1.11 * shlex 2.0.1 (new transitive dep of cc)

library: bump cc to 1.4.3

055eace

Also pulls in * find-msvc-tools 0.1.5 -> 0.1.11 * shlex 1.3.0 -> 2.0.1

weihanglo force-pushed the cc-1.4.3 branch from b366ce4 to 055eace Compare August 20, 2026 04:09

rustbot added A-CI Area: Our Github Actions CI A-testsuite Area: The testsuite used to check the correctness of rustc T-infra Relevant to the infrastructure team, which will review and decide on the PR/issue. labels Aug 20, 2026

This comment has been minimized.

Sign in to view

rustbot added the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Aug 20, 2026

This comment has been minimized.

Sign in to view

rust-bors Bot pushed a commit that referenced this pull request Aug 20, 2026

Auto merge of #161260 - weihanglo:cc-1.4.3, r=<try>

a5859e2

chore: bump to cc@1.4.3 for rustc_llvm and library try-job: dist-aarch64-linux

This comment has been minimized.

Sign in to view

rustbot removed the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Aug 20, 2026

Uh oh!

Uh oh!

Conversation

weihanglo commented Aug 17, 2026 • edited by rustbot Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

What is this?

How to review

Uh oh!

rustbot commented Aug 17, 2026

Uh oh!

weihanglo commented Aug 17, 2026

Uh oh!

This comment has been minimized.

This comment has been minimized.

rust-bors Bot commented Aug 17, 2026

Uh oh!

This comment has been minimized.

rust-timer commented Aug 17, 2026

Overall result: no relevant changes - no action needed

Uh oh!

weihanglo commented Aug 17, 2026

Uh oh!

weihanglo commented Aug 17, 2026

Uh oh!

This comment has been minimized.

This comment has been minimized.

rust-bors Bot commented Aug 17, 2026

Uh oh!

This comment has been minimized.

rust-timer commented Aug 18, 2026

Overall result: no relevant changes - no action needed

Uh oh!

weihanglo commented Aug 18, 2026

Uh oh!

This comment has been minimized.

This comment has been minimized.

rust-bors Bot commented Aug 19, 2026

Uh oh!

weihanglo commented Aug 19, 2026

Uh oh!

weihanglo commented Aug 19, 2026

Uh oh!

weihanglo commented Aug 20, 2026

Uh oh!

This comment has been minimized.

This comment has been minimized.

rust-bors Bot commented Aug 20, 2026

Uh oh!

This comment has been minimized.

rust-timer commented Aug 20, 2026

Overall result: no relevant changes - BENCHMARK(S) FAILED

Uh oh!

Kobzol commented Aug 20, 2026

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

7 participants

weihanglo commented Aug 17, 2026 •

edited by rustbot

Loading