Run mir-opt panic=abort tests on CI - #160200

Kobzol · 2026-07-30T07:54:21Z

Context: https://rust-lang.zulipchat.com/#narrow/channel/131828-t-compiler/topic/Blessing.20mir-opt.20on.20a.20clean.20checkout.20produces.20a.20diff/near/613465816

It looks like we didn't run them on CI (ever? lol).

r? @RalfJung

rustbot · 2026-07-30T07:54:27Z

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

jieyouxu · 2026-07-30T08:20:56Z

cf. #154607

jieyouxu · 2026-07-30T08:21:55Z

+        let panic_abort_target = builder
+            .ensure(MirOptPanicAbortSyntheticTarget { compiler: self.compiler, base: self.target });
+        run(panic_abort_target);


Question: hm, could we have this show up in a step resolution snapshot?

View changes since the review

We have it shown in the step snapshot tests. Do you want to separate it so that instead of running mir-opt directly within the step, we generate two steps, one without mir-opt and another with mir-opt? And when blessing, we move the generation of additional steps to make_run?

RalfJung · 2026-07-30T08:33:37Z

I don't know nearly enough about bootstrap to review this.^^
@rustbot reroll

RalfJung · 2026-07-30T08:34:28Z

+        // Now also run the tests for the host with panic=abort
+        let panic_abort_target = builder
+            .ensure(MirOptPanicAbortSyntheticTarget { compiler: self.compiler, base: self.target });
+        run(panic_abort_target);


This will be redundant with --bless I think?
mir-opt --bless already takes very long due to all the sysroots it is building, I'd prefer it not to become even slower.

View changes since the review

It is only redundant if the host target matches the hardcoded targets we have below. I can add an if condition to skip them if they match the host target.

That being said, if the stdlib it built, re-running the tests again should be very fast, they will just be ignored.

It is always redundant. There are only 4 actually distinct configurations, so running more than 4 targets on --bless is redundant.

I see, so the target doesn't really matter, the only thing that matters is bitwidth and the panic strategy? Yeah, in that case I will try to optimize it to always run 2 targets when not blessing, and 4 targets when blessing.

Yeah.

When checking it's good to check the actual self.target to ensure CI covers them all. But in principle only the bitwidth and panic strategy should matter.

RalfJung · 2026-07-30T08:38:24Z

Cc @saethlin

RalfJung · 2026-07-30T08:42:18Z

The existing behavior of --bless is kind of annoying since it takes so long to build all these sysroots... and it actually builds 5 sysroots when 4 should be enough. (With this PR as-is it'd become 6 sysroots!) Not sure if there is something we could improve there. Does bootstrap know whether self.target is a 32bit target or 64bit target? If yes, we could bless

current target
current target with panic=abort
target of other bitwidth
target of other bitwidth with panic=abort

And only run the first two steps for non-bless mode. That'd be nice.

Kobzol · 2026-08-07T07:28:14Z

And only run the first two steps for non-bless mode. That'd be nice.

But when we do the check, we should test all 4 combinations, right? Otherwise we could get back into the same problem, where some of the combinations are not checked on CI, and thus bless becomes "dirty".

RalfJung · 2026-08-07T07:30:57Z

We are running mir-opt tests on all tier 1 targets, right? So 32bit and 64bit are both covered.

Kobzol · 2026-08-07T07:32:05Z

Ah, I see, makes sense. Thanks.

And only include the target name when rendering test metadata, to avoid including filenames in it.

…anicStrategy`

… of targets to check

rustbot · 2026-08-07T08:23:33Z

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.

Kobzol · 2026-08-07T08:24:41Z

Ok, I refactored the whole thing. Now when checking, we run the current target, and then the current target with the "inverted" panic strategy. And when blessing, we run the current target + four fixed targets, as before (there was a comment saying that running also the current target when blessing is desired).

It is now possible to create synthetic targets with both panic abort/unwind strategies, and the generated miropt test steps are now created as separate step instances, which means that they will be more explicit tin the step trace, and they will also be properly cached.

RalfJung · 2026-08-07T08:56:24Z

-            // selection covers all our tier 1 operating systems and architectures using only tier
-            // 1 targets.
+            // We also include the host target, since some tests use very specific `only` clauses
+            // that are not covered by the target set below.


Suggested change

// that are not covered by the target set below.

// that are not covered by the target set below.

// FIXME: In the future it'd be great to skip one of the other 4 targets if its

// bit-width and panic combination is already covered by the host.

View changes since the review

I implemented the optimization right away.

rust-log-analyzer · 2026-08-07T10:43:16Z

The job aarch64-gnu-llvm-21-1 failed! Check out the build log: (web) (plain enhanced) (plain)

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


##[endgroup]
[TIMING:end] test::Compiletest { test_compiler: Compiler { stage: 2, host: aarch64-unknown-linux-gnu, forced_compiler: false }, target: aarch64-unknown-linux-gnu, mode: coverage-run, suite: "coverage", path: "tests/coverage", compare_mode: None } -- 0.087
[TIMING:end] test::Coverage { compiler: Compiler { stage: 2, host: aarch64-unknown-linux-gnu, forced_compiler: false }, target: aarch64-unknown-linux-gnu, mode: coverage-run } -- 0.000
[TIMING:start] synthetic_targets::SyntheticTargetWithPanicStrategy { compiler: Compiler { stage: 2, host: aarch64-unknown-linux-gnu, forced_compiler: false }, base: aarch64-unknown-linux-gnu, strategy: Abort }
[TIMING:end] synthetic_targets::SyntheticTargetWithPanicStrategy { compiler: Compiler { stage: 2, host: aarch64-unknown-linux-gnu, forced_compiler: false }, base: aarch64-unknown-linux-gnu, strategy: Abort } -- 0.000
[TIMING:start] test::MirOpt { compiler: Compiler { stage: 2, host: aarch64-unknown-linux-gnu, forced_compiler: false }, target: aarch64-unknown-linux-gnu }
[TIMING:start] test::Compiletest { test_compiler: Compiler { stage: 2, host: aarch64-unknown-linux-gnu, forced_compiler: false }, target: aarch64-unknown-linux-gnu, mode: mir-opt, suite: "mir-opt", path: "tests/mir-opt", compare_mode: None }
[TIMING:start] compile::Std { target: aarch64-unknown-linux-gnu, build_compiler: Compiler { stage: 2, host: aarch64-unknown-linux-gnu, forced_compiler: false }, crates: [], force_recompile: false, extra_rust_args: [], is_for_mir_opt_tests: true }
Uplifting library (stage1 -> stage2)
[TIMING:end] compile::Std { target: aarch64-unknown-linux-gnu, build_compiler: Compiler { stage: 2, host: aarch64-unknown-linux-gnu, forced_compiler: false }, crates: [], force_recompile: false, extra_rust_args: [], is_for_mir_opt_tests: true } -- 0.000
---

##[endgroup]
[TIMING:end] test::Compiletest { test_compiler: Compiler { stage: 2, host: aarch64-unknown-linux-gnu, forced_compiler: false }, target: aarch64-unknown-linux-gnu, mode: mir-opt, suite: "mir-opt", path: "tests/mir-opt", compare_mode: None } -- 7.872
[TIMING:end] test::MirOpt { compiler: Compiler { stage: 2, host: aarch64-unknown-linux-gnu, forced_compiler: false }, target: aarch64-unknown-linux-gnu } -- 0.000
[TIMING:start] test::MirOpt { compiler: Compiler { stage: 2, host: aarch64-unknown-linux-gnu, forced_compiler: false }, target: aarch64-unknown-linux-gnu-synthetic-miropt-abort(/checkout/obj/build/synthetic-target-specs/aarch64-unknown-linux-gnu-synthetic-miropt-abort.json) }
[TIMING:start] test::Compiletest { test_compiler: Compiler { stage: 2, host: aarch64-unknown-linux-gnu, forced_compiler: false }, target: aarch64-unknown-linux-gnu-synthetic-miropt-abort(/checkout/obj/build/synthetic-target-specs/aarch64-unknown-linux-gnu-synthetic-miropt-abort.json), mode: mir-opt, suite: "mir-opt", path: "tests/mir-opt", compare_mode: None }
[TIMING:start] compile::Std { target: aarch64-unknown-linux-gnu-synthetic-miropt-abort(/checkout/obj/build/synthetic-target-specs/aarch64-unknown-linux-gnu-synthetic-miropt-abort.json), build_compiler: Compiler { stage: 2, host: aarch64-unknown-linux-gnu, forced_compiler: false }, crates: [], force_recompile: false, extra_rust_args: [], is_for_mir_opt_tests: true }
[TIMING:start] compile::StartupObjects { compiler: Compiler { stage: 2, host: aarch64-unknown-linux-gnu, forced_compiler: false }, target: aarch64-unknown-linux-gnu-synthetic-miropt-abort(/checkout/obj/build/synthetic-target-specs/aarch64-unknown-linux-gnu-synthetic-miropt-abort.json) }
[TIMING:end] compile::StartupObjects { compiler: Compiler { stage: 2, host: aarch64-unknown-linux-gnu, forced_compiler: false }, target: aarch64-unknown-linux-gnu-synthetic-miropt-abort(/checkout/obj/build/synthetic-target-specs/aarch64-unknown-linux-gnu-synthetic-miropt-abort.json) } -- 0.000
[TIMING:start] compile::Std { target: aarch64-unknown-linux-gnu-synthetic-miropt-abort(/checkout/obj/build/synthetic-target-specs/aarch64-unknown-linux-gnu-synthetic-miropt-abort.json), build_compiler: Compiler { stage: 1, host: aarch64-unknown-linux-gnu, forced_compiler: false }, crates: [], force_recompile: false, extra_rust_args: [], is_for_mir_opt_tests: false }
[TIMING:start] compile::StartupObjects { compiler: Compiler { stage: 1, host: aarch64-unknown-linux-gnu, forced_compiler: false }, target: aarch64-unknown-linux-gnu-synthetic-miropt-abort(/checkout/obj/build/synthetic-target-specs/aarch64-unknown-linux-gnu-synthetic-miropt-abort.json) }
[TIMING:end] compile::StartupObjects { compiler: Compiler { stage: 1, host: aarch64-unknown-linux-gnu, forced_compiler: false }, target: aarch64-unknown-linux-gnu-synthetic-miropt-abort(/checkout/obj/build/synthetic-target-specs/aarch64-unknown-linux-gnu-synthetic-miropt-abort.json) } -- 0.000
[TIMING:start] builder::Libdir { compiler: Compiler { stage: 1, host: aarch64-unknown-linux-gnu, forced_compiler: false }, target: aarch64-unknown-linux-gnu-synthetic-miropt-abort(/checkout/obj/build/synthetic-target-specs/aarch64-unknown-linux-gnu-synthetic-miropt-abort.json) }
[TIMING:end] builder::Libdir { compiler: Compiler { stage: 1, host: aarch64-unknown-linux-gnu, forced_compiler: false }, target: aarch64-unknown-linux-gnu-synthetic-miropt-abort(/checkout/obj/build/synthetic-target-specs/aarch64-unknown-linux-gnu-synthetic-miropt-abort.json) } -- 0.001

thread 'main' (1120) panicked at src/bootstrap/src/lib.rs:1263:16:
no entry found for key
stack backtrace:
   0: __rustc::rust_begin_unwind
             at /rustc/08d5b675a9b2abdca5e2fe4eabe0e07bbda15d49/library/std/src/panicking.rs:679:5
   1: core::panicking::panic_fmt
             at /rustc/08d5b675a9b2abdca5e2fe4eabe0e07bbda15d49/library/core/src/panicking.rs:80:14
   2: core::panicking::panic_display::<&str>
             at /rustc/08d5b675a9b2abdca5e2fe4eabe0e07bbda15d49/library/core/src/panicking.rs:259:5
   3: core::option::expect_failed
             at /rustc/08d5b675a9b2abdca5e2fe4eabe0e07bbda15d49/library/core/src/option.rs:2260:5
   4: <core::option::Option<&cc::tool::Tool>>::expect
             at /rustc/08d5b675a9b2abdca5e2fe4eabe0e07bbda15d49/library/core/src/option.rs:969:21
   5: <std::collections::hash::map::HashMap<bootstrap::core::config::target_selection::TargetSelection, cc::tool::Tool> as core::ops::index::Index<&bootstrap::core::config::target_selection::TargetSelection>>::index
             at /rustc/08d5b675a9b2abdca5e2fe4eabe0e07bbda15d49/library/std/src/collections/hash/map.rs:1517:23
   6: <bootstrap::Build>::cc
             at /checkout/src/bootstrap/src/lib.rs:1263:16
   7: <bootstrap::Build>::linker
             at /checkout/src/bootstrap/src/lib.rs:1375:23
   8: <bootstrap::core::builder::cargo::Cargo>::configure_linker
             at /checkout/src/bootstrap/src/core/builder/cargo.rs:359:46
   9: <bootstrap::core::builder::cargo::Cargo>::new
             at /checkout/src/bootstrap/src/core/builder/cargo.rs:162:23
  10: <bootstrap::core::build_steps::compile::Std as bootstrap::core::builder::CommandLineStep>::run
             at /checkout/src/bootstrap/src/core/build_steps/compile.rs:264:29
  11: <bootstrap::core::build_steps::compile::Std as bootstrap::core::builder::Step>::run
             at /checkout/src/bootstrap/src/core/builder/mod.rs:131:9
---
  21: <bootstrap::core::builder::Builder>::ensure::<bootstrap::core::build_steps::test::MirOpt>
             at /checkout/src/bootstrap/src/core/builder/mod.rs:1648:36
  22: <bootstrap::core::build_steps::test::MirOpt as bootstrap::core::builder::CommandLineStep>::make_run
             at /checkout/src/bootstrap/src/core/build_steps/test.rs:2193:25
  23: <bootstrap::core::builder::CommandLineStepDescription>::maybe_run
             at /checkout/src/bootstrap/src/core/builder/mod.rs:489:13
  24: bootstrap::core::builder::cli_paths::match_paths_to_steps_and_run
             at /checkout/src/bootstrap/src/core/builder/cli_paths.rs:134:22
  25: <bootstrap::core::builder::Builder>::run_step_descriptions
             at /checkout/src/bootstrap/src/core/builder/mod.rs:1174:9
  26: <bootstrap::core::builder::Builder>::execute_cli
             at /checkout/src/bootstrap/src/core/builder/mod.rs:1132:14
  27: <bootstrap::Build>::build
             at /checkout/src/bootstrap/src/lib.rs:802:25
  28: bootstrap::main
             at /checkout/src/bootstrap/src/bin/main.rs:157:11
  29: <fn() as core::ops::function::FnOnce<()>>::call_once
             at /rustc/08d5b675a9b2abdca5e2fe4eabe0e07bbda15d49/library/core/src/ops/function.rs:250:5
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

Bootstrap has panicked, currently active steps:
test::MirOpt { compiler: Compiler { stage: 2, host: aarch64-unknown-linux-gnu, forced_compiler: false }, target: aarch64-unknown-linux-gnu-synthetic-miropt-abort(/checkout/obj/build/synthetic-target-specs/aarch64-unknown-linux-gnu-synthetic-miropt-abort.json) } at src/bootstrap/src/core/build_steps/test.rs:2193
test::Compiletest { test_compiler: Compiler { stage: 2, host: aarch64-unknown-linux-gnu, forced_compiler: false }, target: aarch64-unknown-linux-gnu-synthetic-miropt-abort(/checkout/obj/build/synthetic-target-specs/aarch64-unknown-linux-gnu-synthetic-miropt-abort.json), mode: mir-opt, suite: "mir-opt", path: "tests/mir-opt", compare_mode: None } at src/bootstrap/src/core/build_steps/test.rs:2198
compile::Std { target: aarch64-unknown-linux-gnu-synthetic-miropt-abort(/checkout/obj/build/synthetic-target-specs/aarch64-unknown-linux-gnu-synthetic-miropt-abort.json), build_compiler: Compiler { stage: 2, host: aarch64-unknown-linux-gnu, forced_compiler: false }, crates: [], force_recompile: false, extra_rust_args: [], is_for_mir_opt_tests: true } at src/bootstrap/src/core/build_steps/test.rs:2306
compile::Std { target: aarch64-unknown-linux-gnu-synthetic-miropt-abort(/checkout/obj/build/synthetic-target-specs/aarch64-unknown-linux-gnu-synthetic-miropt-abort.json), build_compiler: Compiler { stage: 1, host: aarch64-unknown-linux-gnu, forced_compiler: false }, crates: [], force_recompile: false, extra_rust_args: [], is_for_mir_opt_tests: false } at src/bootstrap/src/core/build_steps/compile.rs:220
Build completed unsuccessfully in 0:28:12
  local time: Fri Aug  7 10:43:02 UTC 2026
  network time: Fri, 07 Aug 2026 10:43:02 GMT
##[error]Process completed with exit code 1.
##[group]Run echo "disk usage:"

rustbot assigned RalfJung Jul 30, 2026

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jieyouxu 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 4, 2026

Kobzol added 3 commits August 7, 2026 10:15

Bless bootstrap tests

a3ca89e

And only include the target name when rendering test metadata, to avoid including filenames in it.

Generalize MirOptPanicAbortSyntheticTarget to `SyntheticTargetWithP…

7dc8d27

…anicStrategy`

Create targets for mir-opt tests explicitly and use the minimal set…

b63868d

… of targets to check

Kobzol force-pushed the mir-opt-panic-abort-on-ci branch from a65622e to b63868d Compare August 7, 2026 08:23

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Fix host normalization

910c6bf

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RalfJung reviewed Aug 7, 2026

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Comment thread src/bootstrap/src/core/build_steps/test.rs

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Bless at most four individual targets

0ce420f

Kobzol force-pushed the mir-opt-panic-abort-on-ci branch from 560add1 to 0ce420f Compare August 7, 2026 10:11

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