Update the cc crate for rustc_llvm by bjorn3 · Pull Request #155438 · rust-lang/rust

bjorn3 · 2026-04-17T13:41:33Z

Latest stacker needs a newer cc than 1.2.16 as older versions don't have windows arm64ec support.

rustbot · 2026-04-17T13:41:36Z

These commits modify the Cargo.lock file. Unintentional changes to Cargo.lock can be introduced when switching branches and rebasing PRs.

If this was unintentional then you should revert the changes before this PR is merged.
Otherwise, you can ignore this comment.

rustbot · 2026-04-17T13:41:39Z

r? @Mark-Simulacrum

rustbot has assigned @Mark-Simulacrum.
They will have a look at your PR within the next two weeks and either review your PR or reassign to another reviewer.

Use r? to explicitly pick a reviewer

Why was this reviewer chosen?

The reviewer was selected based on:

Owners of files modified in this PR: @Mark-Simulacrum

bjorn3 · 2026-04-17T13:50:24Z

Given that the previous attempt regressed performance:

@bors try @rust-timer queue

Update the cc crate for rustc_llvm

rust-bors · 2026-04-17T15:58:45Z

☀️ Try build successful (CI)
Build commit: f61a781 (f61a781aa926b40af32168929f416c41f07e54b3, parent: 27dbdb57a2f90b5c90247e6ef14f2657a03473da)

rust-timer · 2026-04-17T16:53:32Z

Finished benchmarking commit (f61a781): comparison URL.

Overall result: ❌ regressions - please read:

Benchmarking means the PR may be perf-sensitive. It's automatically marked not fit for rolling up. Overriding is possible but disadvised: it risks changing compiler perf.

Next, please: If you can, justify the regressions found in this try perf run in writing along with @rustbot label: +perf-regression-triaged. If not, fix the regressions and do another perf run. Neutral or positive results will clear the label automatically.

@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)	0.7%	[0.4%, 3.4%]	247
Regressions ❌ (secondary)	0.9%	[0.0%, 2.7%]	289
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.7%	[0.4%, 3.4%]	247

Max RSS (memory usage)

Results (primary -0.0%, secondary 2.4%)

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

	mean	range	count
Regressions ❌ (primary)	1.5%	[1.5%, 1.5%]	1
Regressions ❌ (secondary)	2.4%	[2.2%, 2.6%]	2
Improvements ✅ (primary)	-1.6%	[-1.6%, -1.6%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-0.0%	[-1.6%, 1.5%]	2

Cycles

Results (secondary -2.2%)

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)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-2.2%	[-2.2%, -2.1%]	2
All ❌✅ (primary)	-	-	0

Binary size

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

Bootstrap: 490.301s -> 492.119s (0.37%)
Artifact size: 394.23 MiB -> 393.76 MiB (-0.12%)

Mark-Simulacrum · 2026-04-18T12:57:35Z

I think we need an explanation if not necessarily a solution (though those regressions look rather large, including on full builds).

@rustbot author

Update a bunch of dependencies to reduce windows-sys duplication This gets rid of windows-sys 0.60 and with the exception of curl and stacker it gets rid of windows-sys 0.59. For stacker getting rid of windows-sys 0.59 is blocked on rust-lang/stacker#145 and #155438.

ChrisDenton · 2026-04-19T12:51:17Z

The nearest to an explanation seems to be #146186 (comment), cc @madsmtm

It would be a bit of a problem if we can never upgrade cc-rs again...

madsmtm · 2026-04-19T15:48:54Z

I never got further than that investigation unfortunately

Update a bunch of dependencies to reduce windows-sys duplication This gets rid of windows-sys 0.60 and with the exception of curl and stacker it gets rid of windows-sys 0.59. For stacker getting rid of windows-sys 0.59 is blocked on rust-lang/stacker#145 and rust-lang/rust#155438.

bjorn3 · 2026-04-23T09:35:52Z

I've ran cachegrind for stm32f4-0.15.1 and I'm now fairly certain that #146186 (comment) was correct about jemalloc being the cause of the slowdown. Cachegrind shows a lot more jemalloc functions after this PR, suggesting less inlining.

bjorn3 · 2026-04-23T09:38:16Z

Pushed a commit to use the first cc release containing rust-lang/cc-rs#1424.

@bors try @rust-timer queue

thomcc · 2026-05-11T17:43:16Z

Maybe you can explicitly pass .flag_if_supported("-flto")?

Unless I'm mistaken, .flag_if_supported("-flto") will only work where we're directly using cc, which is not everywhere in the build (for example, as mentioned, it doesn't cover jemalloc).

Previously, any dependency of ours that was using cc would automatically get -flto when -Clto was passed, but that's not the case anymore (I'm not sure I think that was a good change, although I do understand the logic).

I think the most straightforward way to get this back is possibly to pass -flto via CFLAGS and CXXFLAGS in the environment, as the cc will pick things up specified that way automatically.

That said, doing so could have the side effect of turning on LTO for other parts of the build (as most systems that build C will pick these up, even if they don't parse/translate rustflags, which most don't), which may be a good thing, but also could cause further problems.

bjorn3 · 2026-05-11T17:45:42Z

The code I modified is the code that determines the CFLAGS and CXXFLAGS env vars that will be passed to cargo build.

bjorn3 · 2026-06-18T16:31:02Z

Looks like the code I modified effectively gets ignored in the end: #t-infra/bootstrap > weird code in fill_target_compiler @ 💬

Latest stacker needs a newer cc than 1.2.16 as older versions don't have windows arm64ec support.

rustbot · 2026-07-05T17:24:14Z

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.

bjorn3 · 2026-07-05T17:24:52Z

@bors try @rust-timer queue

rust-timer · 2026-07-05T17:24:54Z

Awaiting bors try build completion.

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

Update the cc crate for rustc_llvm

rust-bors · 2026-07-05T17:39:46Z

💔 Test for 983a800 failed: CI. Failed job:

try - dist-x86_64-linux-quick (web logs, enhanced plaintext logs)

rust-log-analyzer · 2026-07-05T17:39:48Z

The job dist-x86_64-linux-quick failed! Check out the build log: (web) (plain enhanced) (plain)

Click to see the possible cause of the failure (guessed by this bot)

note: to see what the problems were, use the option `--future-incompat-report`, or run `cargo report future-incompatibilities --id 1`
##[endgroup]
[2026-07-05T17:39:06.766Z INFO  opt_dist::timer] Section `Stage 1 (Rustc PGO)` starts
[2026-07-05T17:39:06.766Z INFO  opt_dist::timer] Section `Stage 1 (Rustc PGO) > Build PGO instrumented rustc and LLVM` starts
[2026-07-05T17:39:06.766Z INFO  opt_dist::exec] Executing `RUST_BACKTRACE=full python3 /checkout/x.py build --target x86_64-unknown-linux-gnu --host x86_64-unknown-linux-gnu --stage 2 library/std --set rust.llvm-bitcode-linker=false --set build.extended=false --set rust.codegen-backends=['llvm'] --set rust.deny-warnings=false --rust-profile-generate /tmp/tmp-multistage/opt-artifacts/rustc-pgo --set llvm.thin-lto=false --set llvm.link-shared=true [at /checkout/obj]`
##[group]Building bootstrap
    Finished `dev` profile [unoptimized] target(s) in 0.07s
##[endgroup]
[TIMING:start] compile::Assemble { target_compiler: Compiler { stage: 2, host: x86_64-unknown-linux-gnu, forced_compiler: false } }
[TIMING:start] builder::Libdir { compiler: Compiler { stage: 2, host: x86_64-unknown-linux-gnu, forced_compiler: false }, target: x86_64-unknown-linux-gnu }
---
[  8%] Building CXX object lib/TableGen/CMakeFiles/LLVMTableGen.dir/StringMatcher.cpp.o
[  8%] Building CXX object lib/CAS/CMakeFiles/LLVMCAS.dir/OnDiskDataAllocator.cpp.o
[  8%] Building CXX object lib/DebugInfo/CodeView/CMakeFiles/LLVMDebugInfoCodeView.dir/DebugChecksumsSubsection.cpp.o
[  8%] Building CXX object lib/CAS/CMakeFiles/LLVMCAS.dir/OnDiskGraphDB.cpp.o
terminate called after throwing an instance of '__gnu_cxx::recursive_init_error'
  what():  std::exception
[  8%] Building CXX object lib/CAS/CMakeFiles/LLVMCAS.dir/OnDiskKeyValueDB.cpp.o
[  8%] Building CXX object lib/CAS/CMakeFiles/LLVMCAS.dir/OnDiskTrieRawHashMap.cpp.o
clang++: error: unable to execute command: Aborted (core dumped)
clang++: error: linker command failed due to signal (use -v to see invocation)
gmake[2]: *** [bin/not] Error 1
gmake[1]: *** [utils/not/CMakeFiles/not.dir/all] Error 2
gmake[1]: *** Waiting for unfinished jobs....
[  8%] Building CXX object lib/CAS/CMakeFiles/LLVMCAS.dir/UnifiedOnDiskCache.cpp.o
[  8%] Building CXX object lib/TableGen/CMakeFiles/LLVMTableGen.dir/StringToOffsetTable.cpp.o
[  8%] Linking CXX executable ../../bin/split-file
[  8%] Linking CXX static library ../../libLLVMBitstreamReader.a
---
  11:     0x560ae74521cb - std[47a2d46b774d1631]::panicking::panic_with_hook
                               at /rustc/0417c25868d6dfbd1c291dfeae950504faa6f790/library/std/src/panicking.rs:825:13
  12:     0x560ae7436522 - std[47a2d46b774d1631]::panicking::panic_handler::{closure#0}
                               at /rustc/0417c25868d6dfbd1c291dfeae950504faa6f790/library/std/src/panicking.rs:698:13
  13:     0x560ae742da69 - std[47a2d46b774d1631]::sys::backtrace::__rust_end_short_backtrace::<std[47a2d46b774d1631]::panicking::panic_handler::{closure#0}, !>
                               at /rustc/0417c25868d6dfbd1c291dfeae950504faa6f790/library/std/src/sys/backtrace.rs:182:18
  14:     0x560ae743752d - __rustc[78fecf9cf3d67ec5]::rust_begin_unwind
                               at /rustc/0417c25868d6dfbd1c291dfeae950504faa6f790/library/std/src/panicking.rs:689:5
  15:     0x560ae660bdec - core[509fcdf7a39c491f]::panicking::panic_fmt
                               at /rustc/0417c25868d6dfbd1c291dfeae950504faa6f790/library/core/src/panicking.rs:80:14
  16:     0x560ae6f64637 - cmake[30c47ed045c761cc]::fail
  17:     0x560ae6f642c3 - cmake[30c47ed045c761cc]::run
  18:     0x560ae6f6a2fb - <cmake[30c47ed045c761cc]::Config>::build
  19:     0x560ae687309d - <bootstrap[1e37754010aae0d4]::core::build_steps::llvm::Llvm as bootstrap[1e37754010aae0d4]::core::builder::Step>::run
                               at /checkout/src/bootstrap/src/core/build_steps/llvm.rs:553:13
  20:     0x560ae6d4be50 - <bootstrap[1e37754010aae0d4]::core::builder::Builder>::ensure::<bootstrap[1e37754010aae0d4]::core::build_steps::llvm::Llvm>
                               at /checkout/src/bootstrap/src/core/builder/mod.rs:1607:36
  21:     0x560ae67b7f73 - <bootstrap[1e37754010aae0d4]::core::build_steps::compile::Assemble as bootstrap[1e37754010aae0d4]::core::builder::Step>::run
                               at /checkout/src/bootstrap/src/core/build_steps/compile.rs:2149:69
  22:     0x560ae6e07103 - <bootstrap[1e37754010aae0d4]::core::builder::Builder>::ensure::<bootstrap[1e37754010aae0d4]::core::build_steps::compile::Assemble>
                               at /checkout/src/bootstrap/src/core/builder/mod.rs:1607:36
  23:     0x560ae6e94fe0 - <bootstrap[1e37754010aae0d4]::core::builder::Builder>::compiler
                               at /checkout/src/bootstrap/src/core/builder/mod.rs:1168:14
  24:     0x560ae67af995 - <bootstrap[1e37754010aae0d4]::core::build_steps::compile::Std as bootstrap[1e37754010aae0d4]::core::builder::Step>::make_run
                               at /checkout/src/bootstrap/src/core/build_steps/compile.rs:142:41
  25:     0x560ae6e8a1ca - <bootstrap[1e37754010aae0d4]::core::builder::StepDescription>::maybe_run
                               at /checkout/src/bootstrap/src/core/builder/mod.rs:476:13
  26:     0x560ae66667aa - bootstrap[1e37754010aae0d4]::core::builder::cli_paths::match_paths_to_steps_and_run
                               at /checkout/src/bootstrap/src/core/builder/cli_paths.rs:232:18
  27:     0x560ae6e93f96 - <bootstrap[1e37754010aae0d4]::core::builder::Builder>::run_step_descriptions
                               at /checkout/src/bootstrap/src/core/builder/mod.rs:1140:9
  28:     0x560ae6e8d6c2 - <bootstrap[1e37754010aae0d4]::core::builder::Builder>::execute_cli
                               at /checkout/src/bootstrap/src/core/builder/mod.rs:1119:14
  29:     0x560ae6a8d85c - <bootstrap[1e37754010aae0d4]::Build>::build
                               at /checkout/src/bootstrap/src/lib.rs:803:25
  30:     0x560ae6612d0e - bootstrap[ce725515cf2db4c9]::main
                               at /checkout/src/bootstrap/src/bin/main.rs:130:11
  31:     0x560ae6615d23 - <fn() as core[509fcdf7a39c491f]::ops::function::FnOnce<()>>::call_once
                               at /rustc/0417c25868d6dfbd1c291dfeae950504faa6f790/library/core/src/ops/function.rs:250:5
  32:     0x560ae660d156 - std[47a2d46b774d1631]::sys::backtrace::__rust_begin_short_backtrace::<fn(), ()>
                               at /rustc/0417c25868d6dfbd1c291dfeae950504faa6f790/library/std/src/sys/backtrace.rs:166:18
  33:     0x560ae66105f9 - std[47a2d46b774d1631]::rt::lang_start::<()>::{closure#0}
                               at /rustc/0417c25868d6dfbd1c291dfeae950504faa6f790/library/std/src/rt.rs:206:18
  34:     0x560ae74508b7 - <&dyn core[509fcdf7a39c491f]::ops::function::Fn<(), Output = i32> + core[509fcdf7a39c491f]::marker::Sync + core[509fcdf7a39c491f]::panic::unwind_safe::RefUnwindSafe as core[509fcdf7a39c491f]::ops::function::FnOnce<()>>::call_once
                               at /rustc/0417c25868d6dfbd1c291dfeae950504faa6f790/library/core/src/ops/function.rs:287:21
  35:     0x560ae74508b7 - std[47a2d46b774d1631]::panicking::catch_unwind::do_call::<&dyn core[509fcdf7a39c491f]::ops::function::Fn<(), Output = i32> + core[509fcdf7a39c491f]::marker::Sync + core[509fcdf7a39c491f]::panic::unwind_safe::RefUnwindSafe, i32>
                               at /rustc/0417c25868d6dfbd1c291dfeae950504faa6f790/library/std/src/panicking.rs:581:40
  36:     0x560ae74508b7 - std[47a2d46b774d1631]::panicking::catch_unwind::<i32, &dyn core[509fcdf7a39c491f]::ops::function::Fn<(), Output = i32> + core[509fcdf7a39c491f]::marker::Sync + core[509fcdf7a39c491f]::panic::unwind_safe::RefUnwindSafe>
                               at /rustc/0417c25868d6dfbd1c291dfeae950504faa6f790/library/std/src/panicking.rs:544:19
  37:     0x560ae74508b7 - std[47a2d46b774d1631]::panic::catch_unwind::<&dyn core[509fcdf7a39c491f]::ops::function::Fn<(), Output = i32> + core[509fcdf7a39c491f]::marker::Sync + core[509fcdf7a39c491f]::panic::unwind_safe::RefUnwindSafe, i32>
                               at /rustc/0417c25868d6dfbd1c291dfeae950504faa6f790/library/std/src/panic.rs:359:14
  38:     0x560ae74508b7 - std[47a2d46b774d1631]::rt::lang_start_internal::{closure#0}
                               at /rustc/0417c25868d6dfbd1c291dfeae950504faa6f790/library/std/src/rt.rs:175:24
  39:     0x560ae74508b7 - std[47a2d46b774d1631]::panicking::catch_unwind::do_call::<std[47a2d46b774d1631]::rt::lang_start_internal::{closure#0}, isize>
                               at /rustc/0417c25868d6dfbd1c291dfeae950504faa6f790/library/std/src/panicking.rs:581:40
  40:     0x560ae74508b7 - std[47a2d46b774d1631]::panicking::catch_unwind::<isize, std[47a2d46b774d1631]::rt::lang_start_internal::{closure#0}>
                               at /rustc/0417c25868d6dfbd1c291dfeae950504faa6f790/library/std/src/panicking.rs:544:19
  41:     0x560ae74508b7 - std[47a2d46b774d1631]::panic::catch_unwind::<std[47a2d46b774d1631]::rt::lang_start_internal::{closure#0}, isize>
                               at /rustc/0417c25868d6dfbd1c291dfeae950504faa6f790/library/std/src/panic.rs:359:14
  42:     0x560ae74508b7 - std[47a2d46b774d1631]::rt::lang_start_internal
                               at /rustc/0417c25868d6dfbd1c291dfeae950504faa6f790/library/std/src/rt.rs:171:5
  43:     0x560ae660d091 - std[47a2d46b774d1631]::rt::lang_start::<()>
                               at /rustc/0417c25868d6dfbd1c291dfeae950504faa6f790/library/std/src/rt.rs:205:5
---
[2026-07-05T17:39:38.337Z INFO  opt_dist::utils] Free disk space: 1.30 TiB out of total 2.51 TiB (48.36% used)
Error: Optimized build pipeline has failed

Caused by:
    Command RUST_BACKTRACE=full python3 /checkout/x.py build --target x86_64-unknown-linux-gnu --host x86_64-unknown-linux-gnu --stage 2 library/std --set rust.llvm-bitcode-linker=false --set build.extended=false --set rust.codegen-backends=['llvm'] --set rust.deny-warnings=false --rust-profile-generate /tmp/tmp-multistage/opt-artifacts/rustc-pgo --set llvm.thin-lto=false --set llvm.link-shared=true [at /checkout/obj] has failed with exit code Some(1)

Stack backtrace:
   0: <anyhow::Error>::msg::<alloc::string::String>
             at /rust/deps/anyhow-1.0.102/src/backtrace.rs:10:14
   1: <opt_dist::exec::CmdBuilder>::run
             at /rustc/983a800be9147f45ff2daabf04e08bee070ae35d/src/tools/opt-dist/src/exec.rs:80:17
   2: <opt_dist::exec::Bootstrap>::run
             at /rustc/983a800be9147f45ff2daabf04e08bee070ae35d/src/tools/opt-dist/src/exec.rs:199:18
   3: opt_dist::execute_pipeline::{closure#1}::{closure#0}
             at /rustc/983a800be9147f45ff2daabf04e08bee070ae35d/src/tools/opt-dist/src/main.rs:256:21
   4: <opt_dist::timer::TimerSection>::section::<opt_dist::execute_pipeline::{closure#1}::{closure#0}, ()>
             at /rustc/983a800be9147f45ff2daabf04e08bee070ae35d/src/tools/opt-dist/src/timer.rs:111:22
   5: opt_dist::execute_pipeline::{closure#1}
             at /rustc/983a800be9147f45ff2daabf04e08bee070ae35d/src/tools/opt-dist/src/main.rs:245:15
   6: <opt_dist::timer::TimerSection>::section::<opt_dist::execute_pipeline::{closure#1}, opt_dist::training::RustcPGOProfile>
             at /rustc/983a800be9147f45ff2daabf04e08bee070ae35d/src/tools/opt-dist/src/timer.rs:111:22
   7: opt_dist::execute_pipeline
             at /rustc/983a800be9147f45ff2daabf04e08bee070ae35d/src/tools/opt-dist/src/main.rs:242:35
   8: opt_dist::main
             at /rustc/983a800be9147f45ff2daabf04e08bee070ae35d/src/tools/opt-dist/src/main.rs:469:18
   9: <fn() -> core::result::Result<(), anyhow::Error> as core::ops::function::FnOnce<()>>::call_once
             at /rustc/0417c25868d6dfbd1c291dfeae950504faa6f790/library/core/src/ops/function.rs:250:5
  10: std::sys::backtrace::__rust_begin_short_backtrace::<fn() -> core::result::Result<(), anyhow::Error>, core::result::Result<(), anyhow::Error>>
             at /rustc/0417c25868d6dfbd1c291dfeae950504faa6f790/library/std/src/sys/backtrace.rs:166:18
  11: std::rt::lang_start::<core::result::Result<(), anyhow::Error>>::{closure#0}
             at /rustc/0417c25868d6dfbd1c291dfeae950504faa6f790/library/std/src/rt.rs:206:18
  12: <&dyn core::ops::function::Fn<(), Output = i32> + core::marker::Sync + core::panic::unwind_safe::RefUnwindSafe as core::ops::function::FnOnce<()>>::call_once
             at /rustc/0417c25868d6dfbd1c291dfeae950504faa6f790/library/core/src/ops/function.rs:287:21
  13: std::panicking::catch_unwind::do_call::<&dyn core::ops::function::Fn<(), Output = i32> + core::marker::Sync + core::panic::unwind_safe::RefUnwindSafe, i32>
             at /rustc/0417c25868d6dfbd1c291dfeae950504faa6f790/library/std/src/panicking.rs:581:40
  14: std::panicking::catch_unwind::<i32, &dyn core::ops::function::Fn<(), Output = i32> + core::marker::Sync + core::panic::unwind_safe::RefUnwindSafe>
             at /rustc/0417c25868d6dfbd1c291dfeae950504faa6f790/library/std/src/panicking.rs:544:19
  15: std::panic::catch_unwind::<&dyn core::ops::function::Fn<(), Output = i32> + core::marker::Sync + core::panic::unwind_safe::RefUnwindSafe, i32>
             at /rustc/0417c25868d6dfbd1c291dfeae950504faa6f790/library/std/src/panic.rs:359:14
  16: std::rt::lang_start_internal::{closure#0}
             at /rustc/0417c25868d6dfbd1c291dfeae950504faa6f790/library/std/src/rt.rs:175:24
  17: std::panicking::catch_unwind::do_call::<std::rt::lang_start_internal::{closure#0}, isize>
             at /rustc/0417c25868d6dfbd1c291dfeae950504faa6f790/library/std/src/panicking.rs:581:40

bjorn3 · 2026-07-05T17:43:08Z

terminate called after throwing an instance of '__gnu_cxx::recursive_init_error'
  what():  std::exception
[  8%] Building CXX object lib/CAS/CMakeFiles/LLVMCAS.dir/OnDiskKeyValueDB.cpp.o
[  8%] Building CXX object lib/CAS/CMakeFiles/LLVMCAS.dir/OnDiskTrieRawHashMap.cpp.o
clang++: error: unable to execute command: Aborted (core dumped)
clang++: error: linker command failed due to signal (use -v to see invocation)

@bors try @rust-timer queue

rust-timer · 2026-07-05T17:43:11Z

This pull request is already queued and waiting for a try build to finish.

Update the cc crate for rustc_llvm

rust-bors · 2026-07-05T17:55:31Z

💔 Test for 5852e40 failed: CI. Failed job:

try - dist-x86_64-linux-quick (web logs, enhanced plaintext logs)

rust-log-analyzer · 2026-07-05T17:55:33Z

The job dist-x86_64-linux-quick failed! Check out the build log: (web) (plain enhanced) (plain)

Click to see the possible cause of the failure (guessed by this bot)

note: to see what the problems were, use the option `--future-incompat-report`, or run `cargo report future-incompatibilities --id 1`
##[endgroup]
[2026-07-05T17:55:03.027Z INFO  opt_dist::timer] Section `Stage 1 (Rustc PGO)` starts
[2026-07-05T17:55:03.027Z INFO  opt_dist::timer] Section `Stage 1 (Rustc PGO) > Build PGO instrumented rustc and LLVM` starts
[2026-07-05T17:55:03.027Z INFO  opt_dist::exec] Executing `RUST_BACKTRACE=full python3 /checkout/x.py build --target x86_64-unknown-linux-gnu --host x86_64-unknown-linux-gnu --stage 2 library/std --set rust.llvm-bitcode-linker=false --set build.extended=false --set rust.codegen-backends=['llvm'] --set rust.deny-warnings=false --rust-profile-generate /tmp/tmp-multistage/opt-artifacts/rustc-pgo --set llvm.thin-lto=false --set llvm.link-shared=true [at /checkout/obj]`
##[group]Building bootstrap
    Finished `dev` profile [unoptimized] target(s) in 0.06s
##[endgroup]
[TIMING:start] compile::Assemble { target_compiler: Compiler { stage: 2, host: x86_64-unknown-linux-gnu, forced_compiler: false } }
[TIMING:start] builder::Libdir { compiler: Compiler { stage: 2, host: x86_64-unknown-linux-gnu, forced_compiler: false }, target: x86_64-unknown-linux-gnu }
---
[  9%] Building CXX object lib/DebugInfo/CodeView/CMakeFiles/LLVMDebugInfoCodeView.dir/TypeStreamMerger.cpp.o
[  9%] Building CXX object lib/DebugInfo/CodeView/CMakeFiles/LLVMDebugInfoCodeView.dir/TypeTableCollection.cpp.o
terminate called after throwing an instance of '__gnu_cxx::recursive_init_error'
[  9%] Linking CXX executable ../../bin/llvm-min-tblgen
  what():  std::exception
clang++: error: unable to execute command: Aborted (core dumped)
clang++: error: linker command failed due to signal (use -v to see invocation)
gmake[2]: *** [bin/UnicodeNameMappingGenerator] Error 1
gmake[1]: *** [utils/UnicodeData/CMakeFiles/UnicodeNameMappingGenerator.dir/all] Error 2
gmake[1]: *** Waiting for unfinished jobs....
[  9%] Built target not
[  9%] Linking CXX static library ../../libLLVMDebugInfoCodeView.a
[  9%] Built target LLVMDebugInfoCodeView
[  9%] Built target split-file
---
  11:     0x55f1b559a1cb - std[47a2d46b774d1631]::panicking::panic_with_hook
                               at /rustc/0417c25868d6dfbd1c291dfeae950504faa6f790/library/std/src/panicking.rs:825:13
  12:     0x55f1b557e522 - std[47a2d46b774d1631]::panicking::panic_handler::{closure#0}
                               at /rustc/0417c25868d6dfbd1c291dfeae950504faa6f790/library/std/src/panicking.rs:698:13
  13:     0x55f1b5575a69 - std[47a2d46b774d1631]::sys::backtrace::__rust_end_short_backtrace::<std[47a2d46b774d1631]::panicking::panic_handler::{closure#0}, !>
                               at /rustc/0417c25868d6dfbd1c291dfeae950504faa6f790/library/std/src/sys/backtrace.rs:182:18
  14:     0x55f1b557f52d - __rustc[78fecf9cf3d67ec5]::rust_begin_unwind
                               at /rustc/0417c25868d6dfbd1c291dfeae950504faa6f790/library/std/src/panicking.rs:689:5
  15:     0x55f1b4753dec - core[509fcdf7a39c491f]::panicking::panic_fmt
                               at /rustc/0417c25868d6dfbd1c291dfeae950504faa6f790/library/core/src/panicking.rs:80:14
  16:     0x55f1b50ac637 - cmake[30c47ed045c761cc]::fail
  17:     0x55f1b50ac2c3 - cmake[30c47ed045c761cc]::run
  18:     0x55f1b50b22fb - <cmake[30c47ed045c761cc]::Config>::build
  19:     0x55f1b49bb09d - <bootstrap[1e37754010aae0d4]::core::build_steps::llvm::Llvm as bootstrap[1e37754010aae0d4]::core::builder::Step>::run
                               at /checkout/src/bootstrap/src/core/build_steps/llvm.rs:553:13
  20:     0x55f1b4e93e50 - <bootstrap[1e37754010aae0d4]::core::builder::Builder>::ensure::<bootstrap[1e37754010aae0d4]::core::build_steps::llvm::Llvm>
                               at /checkout/src/bootstrap/src/core/builder/mod.rs:1607:36
  21:     0x55f1b48fff73 - <bootstrap[1e37754010aae0d4]::core::build_steps::compile::Assemble as bootstrap[1e37754010aae0d4]::core::builder::Step>::run
                               at /checkout/src/bootstrap/src/core/build_steps/compile.rs:2149:69
  22:     0x55f1b4f4f103 - <bootstrap[1e37754010aae0d4]::core::builder::Builder>::ensure::<bootstrap[1e37754010aae0d4]::core::build_steps::compile::Assemble>
                               at /checkout/src/bootstrap/src/core/builder/mod.rs:1607:36
  23:     0x55f1b4fdcfe0 - <bootstrap[1e37754010aae0d4]::core::builder::Builder>::compiler
                               at /checkout/src/bootstrap/src/core/builder/mod.rs:1168:14
  24:     0x55f1b48f7995 - <bootstrap[1e37754010aae0d4]::core::build_steps::compile::Std as bootstrap[1e37754010aae0d4]::core::builder::Step>::make_run
                               at /checkout/src/bootstrap/src/core/build_steps/compile.rs:142:41
  25:     0x55f1b4fd21ca - <bootstrap[1e37754010aae0d4]::core::builder::StepDescription>::maybe_run
                               at /checkout/src/bootstrap/src/core/builder/mod.rs:476:13
  26:     0x55f1b47ae7aa - bootstrap[1e37754010aae0d4]::core::builder::cli_paths::match_paths_to_steps_and_run
                               at /checkout/src/bootstrap/src/core/builder/cli_paths.rs:232:18
  27:     0x55f1b4fdbf96 - <bootstrap[1e37754010aae0d4]::core::builder::Builder>::run_step_descriptions
                               at /checkout/src/bootstrap/src/core/builder/mod.rs:1140:9
  28:     0x55f1b4fd56c2 - <bootstrap[1e37754010aae0d4]::core::builder::Builder>::execute_cli
                               at /checkout/src/bootstrap/src/core/builder/mod.rs:1119:14
  29:     0x55f1b4bd585c - <bootstrap[1e37754010aae0d4]::Build>::build
                               at /checkout/src/bootstrap/src/lib.rs:803:25
  30:     0x55f1b475ad0e - bootstrap[ce725515cf2db4c9]::main
                               at /checkout/src/bootstrap/src/bin/main.rs:130:11
  31:     0x55f1b475dd23 - <fn() as core[509fcdf7a39c491f]::ops::function::FnOnce<()>>::call_once
                               at /rustc/0417c25868d6dfbd1c291dfeae950504faa6f790/library/core/src/ops/function.rs:250:5
  32:     0x55f1b4755156 - std[47a2d46b774d1631]::sys::backtrace::__rust_begin_short_backtrace::<fn(), ()>
                               at /rustc/0417c25868d6dfbd1c291dfeae950504faa6f790/library/std/src/sys/backtrace.rs:166:18
  33:     0x55f1b47585f9 - std[47a2d46b774d1631]::rt::lang_start::<()>::{closure#0}
                               at /rustc/0417c25868d6dfbd1c291dfeae950504faa6f790/library/std/src/rt.rs:206:18
  34:     0x55f1b55988b7 - <&dyn core[509fcdf7a39c491f]::ops::function::Fn<(), Output = i32> + core[509fcdf7a39c491f]::marker::Sync + core[509fcdf7a39c491f]::panic::unwind_safe::RefUnwindSafe as core[509fcdf7a39c491f]::ops::function::FnOnce<()>>::call_once
                               at /rustc/0417c25868d6dfbd1c291dfeae950504faa6f790/library/core/src/ops/function.rs:287:21
  35:     0x55f1b55988b7 - std[47a2d46b774d1631]::panicking::catch_unwind::do_call::<&dyn core[509fcdf7a39c491f]::ops::function::Fn<(), Output = i32> + core[509fcdf7a39c491f]::marker::Sync + core[509fcdf7a39c491f]::panic::unwind_safe::RefUnwindSafe, i32>
                               at /rustc/0417c25868d6dfbd1c291dfeae950504faa6f790/library/std/src/panicking.rs:581:40
  36:     0x55f1b55988b7 - std[47a2d46b774d1631]::panicking::catch_unwind::<i32, &dyn core[509fcdf7a39c491f]::ops::function::Fn<(), Output = i32> + core[509fcdf7a39c491f]::marker::Sync + core[509fcdf7a39c491f]::panic::unwind_safe::RefUnwindSafe>
                               at /rustc/0417c25868d6dfbd1c291dfeae950504faa6f790/library/std/src/panicking.rs:544:19
  37:     0x55f1b55988b7 - std[47a2d46b774d1631]::panic::catch_unwind::<&dyn core[509fcdf7a39c491f]::ops::function::Fn<(), Output = i32> + core[509fcdf7a39c491f]::marker::Sync + core[509fcdf7a39c491f]::panic::unwind_safe::RefUnwindSafe, i32>
                               at /rustc/0417c25868d6dfbd1c291dfeae950504faa6f790/library/std/src/panic.rs:359:14
  38:     0x55f1b55988b7 - std[47a2d46b774d1631]::rt::lang_start_internal::{closure#0}
                               at /rustc/0417c25868d6dfbd1c291dfeae950504faa6f790/library/std/src/rt.rs:175:24
  39:     0x55f1b55988b7 - std[47a2d46b774d1631]::panicking::catch_unwind::do_call::<std[47a2d46b774d1631]::rt::lang_start_internal::{closure#0}, isize>
                               at /rustc/0417c25868d6dfbd1c291dfeae950504faa6f790/library/std/src/panicking.rs:581:40
  40:     0x55f1b55988b7 - std[47a2d46b774d1631]::panicking::catch_unwind::<isize, std[47a2d46b774d1631]::rt::lang_start_internal::{closure#0}>
                               at /rustc/0417c25868d6dfbd1c291dfeae950504faa6f790/library/std/src/panicking.rs:544:19
  41:     0x55f1b55988b7 - std[47a2d46b774d1631]::panic::catch_unwind::<std[47a2d46b774d1631]::rt::lang_start_internal::{closure#0}, isize>
                               at /rustc/0417c25868d6dfbd1c291dfeae950504faa6f790/library/std/src/panic.rs:359:14
  42:     0x55f1b55988b7 - std[47a2d46b774d1631]::rt::lang_start_internal
                               at /rustc/0417c25868d6dfbd1c291dfeae950504faa6f790/library/std/src/rt.rs:171:5
  43:     0x55f1b4755091 - std[47a2d46b774d1631]::rt::lang_start::<()>
                               at /rustc/0417c25868d6dfbd1c291dfeae950504faa6f790/library/std/src/rt.rs:205:5
---
[2026-07-05T17:55:20.584Z INFO  opt_dist::utils] Free disk space: 1.29 TiB out of total 2.51 TiB (48.36% used)
Error: Optimized build pipeline has failed

Caused by:
    Command RUST_BACKTRACE=full python3 /checkout/x.py build --target x86_64-unknown-linux-gnu --host x86_64-unknown-linux-gnu --stage 2 library/std --set rust.llvm-bitcode-linker=false --set build.extended=false --set rust.codegen-backends=['llvm'] --set rust.deny-warnings=false --rust-profile-generate /tmp/tmp-multistage/opt-artifacts/rustc-pgo --set llvm.thin-lto=false --set llvm.link-shared=true [at /checkout/obj] has failed with exit code Some(1)

Stack backtrace:
   0: <anyhow::Error>::msg::<alloc::string::String>
             at /rust/deps/anyhow-1.0.102/src/backtrace.rs:10:14
   1: <opt_dist::exec::CmdBuilder>::run
             at /rustc/5852e40d78ba87bc4e873c7e5fd214f3b1bca062/src/tools/opt-dist/src/exec.rs:80:17
   2: <opt_dist::exec::Bootstrap>::run
             at /rustc/5852e40d78ba87bc4e873c7e5fd214f3b1bca062/src/tools/opt-dist/src/exec.rs:199:18
   3: opt_dist::execute_pipeline::{closure#1}::{closure#0}
             at /rustc/5852e40d78ba87bc4e873c7e5fd214f3b1bca062/src/tools/opt-dist/src/main.rs:256:21
   4: <opt_dist::timer::TimerSection>::section::<opt_dist::execute_pipeline::{closure#1}::{closure#0}, ()>
             at /rustc/5852e40d78ba87bc4e873c7e5fd214f3b1bca062/src/tools/opt-dist/src/timer.rs:111:22
   5: opt_dist::execute_pipeline::{closure#1}
             at /rustc/5852e40d78ba87bc4e873c7e5fd214f3b1bca062/src/tools/opt-dist/src/main.rs:245:15
   6: <opt_dist::timer::TimerSection>::section::<opt_dist::execute_pipeline::{closure#1}, opt_dist::training::RustcPGOProfile>
             at /rustc/5852e40d78ba87bc4e873c7e5fd214f3b1bca062/src/tools/opt-dist/src/timer.rs:111:22
   7: opt_dist::execute_pipeline
             at /rustc/5852e40d78ba87bc4e873c7e5fd214f3b1bca062/src/tools/opt-dist/src/main.rs:242:35
   8: opt_dist::main
             at /rustc/5852e40d78ba87bc4e873c7e5fd214f3b1bca062/src/tools/opt-dist/src/main.rs:469:18
   9: <fn() -> core::result::Result<(), anyhow::Error> as core::ops::function::FnOnce<()>>::call_once
             at /rustc/0417c25868d6dfbd1c291dfeae950504faa6f790/library/core/src/ops/function.rs:250:5
  10: std::sys::backtrace::__rust_begin_short_backtrace::<fn() -> core::result::Result<(), anyhow::Error>, core::result::Result<(), anyhow::Error>>
             at /rustc/0417c25868d6dfbd1c291dfeae950504faa6f790/library/std/src/sys/backtrace.rs:166:18
  11: std::rt::lang_start::<core::result::Result<(), anyhow::Error>>::{closure#0}
             at /rustc/0417c25868d6dfbd1c291dfeae950504faa6f790/library/std/src/rt.rs:206:18
  12: <&dyn core::ops::function::Fn<(), Output = i32> + core::marker::Sync + core::panic::unwind_safe::RefUnwindSafe as core::ops::function::FnOnce<()>>::call_once
             at /rustc/0417c25868d6dfbd1c291dfeae950504faa6f790/library/core/src/ops/function.rs:287:21
  13: std::panicking::catch_unwind::do_call::<&dyn core::ops::function::Fn<(), Output = i32> + core::marker::Sync + core::panic::unwind_safe::RefUnwindSafe, i32>
             at /rustc/0417c25868d6dfbd1c291dfeae950504faa6f790/library/std/src/panicking.rs:581:40
  14: std::panicking::catch_unwind::<i32, &dyn core::ops::function::Fn<(), Output = i32> + core::marker::Sync + core::panic::unwind_safe::RefUnwindSafe>
             at /rustc/0417c25868d6dfbd1c291dfeae950504faa6f790/library/std/src/panicking.rs:544:19
  15: std::panic::catch_unwind::<&dyn core::ops::function::Fn<(), Output = i32> + core::marker::Sync + core::panic::unwind_safe::RefUnwindSafe, i32>
             at /rustc/0417c25868d6dfbd1c291dfeae950504faa6f790/library/std/src/panic.rs:359:14
  16: std::rt::lang_start_internal::{closure#0}
             at /rustc/0417c25868d6dfbd1c291dfeae950504faa6f790/library/std/src/rt.rs:175:24
  17: std::panicking::catch_unwind::do_call::<std::rt::lang_start_internal::{closure#0}, isize>
             at /rustc/0417c25868d6dfbd1c291dfeae950504faa6f790/library/std/src/panicking.rs:581:40

Fix typo Extracted out of rust-lang#155438

rustbot assigned Mark-Simulacrum Apr 17, 2026

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

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

Auto merge of #155438 - bjorn3:update_cc, r=<try>

f61a781

Update the cc crate for rustc_llvm

bjorn3 mentioned this pull request Apr 17, 2026

Update a bunch of dependencies to reduce windows-sys duplication #155444

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rustbot added perf-regression Performance regression. and removed S-waiting-on-perf Status: Waiting on a perf run to be completed. labels Apr 17, 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 Apr 18, 2026

This was referenced Apr 21, 2026

Outdated cc crates in rustc lead to incorrect toolchain use on m68k #155602

Open

Allow windows-sys 0.61 rust-lang/stacker#145

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bjorn3 added 8 commits July 5, 2026 19:19

Update the cc crate for rustc_llvm

545b128

Latest stacker needs a newer cc than 1.2.16 as older versions don't have windows arm64ec support.

[PERF] Downgrade to 1.2.21

f995b77

[PERF] Update to cc 1.2.30

7ad9e19

[PERF] Update to 1.2.35

cc938b4

[PERF] Update to 1.2.37

d683a61

Fix typo

80f2615

Build C code with LTO when LTO is enabled for rust code

f94d7f1

Update the cc crate for rustc_llvm

221e2b0

Latest stacker needs a newer cc than 1.2.16 as older versions don't have windows arm64ec support.

bjorn3 force-pushed the update_cc branch from 5d56260 to 221e2b0 Compare July 5, 2026 17:24

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rustbot added the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Jul 5, 2026

rust-bors Bot pushed a commit that referenced this pull request Jul 5, 2026

Auto merge of #155438 - bjorn3:update_cc, r=<try>

983a800

Update the cc crate for rustc_llvm

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rust-bors Bot pushed a commit that referenced this pull request Jul 5, 2026

Auto merge of #155438 - bjorn3:update_cc, r=<try>

5852e40

Update the cc crate for rustc_llvm

bjorn3 mentioned this pull request Jul 5, 2026

Fix typo #158825

Open

JonathanBrouwer added a commit to JonathanBrouwer/rust that referenced this pull request Jul 5, 2026

Rollup merge of rust-lang#158825 - bjorn3:fix_typo, r=clubby789

bde5bb9

Fix typo Extracted out of rust-lang#155438

jhpratt added a commit to jhpratt/rust that referenced this pull request Jul 6, 2026

Rollup merge of rust-lang#158825 - bjorn3:fix_typo, r=clubby789

f423b10

Fix typo Extracted out of rust-lang#155438

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rust-timer commented Apr 17, 2026

Overall result: ❌ regressions - please read:

Instruction count

Max RSS (memory usage)

Cycles

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bjorn3 commented Apr 17, 2026 •

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