Let miri and const eval execute intrinsics' fallback bodies #124293

oli-obk · 2024-04-23T13:33:09Z

fixes rust-lang/miri#3397

r? @RalfJung

rustbot · 2024-04-23T13:33:19Z

Some changes occurred to the CTFE / Miri engine

cc @rust-lang/miri

The Miri subtree was changed

cc @rust-lang/miri

compiler/rustc_const_eval/src/const_eval/dummy_machine.rs

oli-obk · 2024-04-23T13:35:02Z

compiler/rustc_const_eval/src/interpret/terminator.rs

 self,
 instance,
 &self.copy_fn_args(args),
 destination,
 target,
 unwind,
- )
+ )? {
+ assert!(!self.tcx.intrinsic(fallback.def_id()).unwrap().must_be_overridden);


We only assert here, so backends are forced to choose a way to report the lack of intrinsic implementation, as miri and ctfe differ here in the message we want to send.

oli-obk · 2024-04-23T13:35:22Z

src/tools/miri/src/shims/intrinsics/mod.rs

+ let intrinsic_fallback_checks_ub = Symbol::intern("intrinsic_fallback_checks_ub");
+ if !this.tcx.item_attrs(instance.def_id()).iter().any(|attr| attr.path_matches(&[sym::miri, intrinsic_fallback_checks_ub])) {
+ throw_unsup_format!("miri can only use intrinsics that preserve UB. After verifying that `{intrinsic_name}` does so, add the `#[miri::intrinsic_fallback_checks_ub]` attribute to it");
+ }


We could skip this check for safe intrinsics

src/tools/miri/src/shims/intrinsics/mod.rs

RalfJung

The approach LGTM, thanks! I left some notes, mostly minor.

Please also add a test ensuring that we notice when an intrinsic does not have the intrinsic_fallback_checks_ub attribute.

compiler/rustc_const_eval/src/const_eval/machine.rs

compiler/rustc_const_eval/src/interpret/machine.rs

compiler/rustc_const_eval/src/interpret/terminator.rs

src/tools/miri/src/shims/intrinsics/atomic.rs

src/tools/miri/src/shims/intrinsics/mod.rs

RalfJung · 2024-04-29T15:27:54Z

@rustbot author

oli-obk · 2024-04-29T16:29:59Z

@rustbot ready

src/tools/miri/src/shims/intrinsics/mod.rs

compiler/rustc_const_eval/src/const_eval/machine.rs

src/tools/miri/src/shims/intrinsics/mod.rs

RalfJung · 2024-04-30T15:00:31Z

src/tools/miri/src/shims/intrinsics/mod.rs

+ return Ok(Some(ty::Instance {
+ def: ty::InstanceDef::Item(instance.def_id()),
+ args: instance.args,
+ }))


A few lines above we have "Handle intrinsics without return place" for diverging intrinsics -- shouldn't that also check for a fallback body?

probably. Let's add that when we have such an intrinsic with a fallback body

Let's at least add a FIXME then.

src/tools/miri/src/shims/intrinsics/mod.rs

RalfJung · 2024-05-02T10:22:29Z

r=me with tests blessed and FIXME added.

…to preserve all UB that the native intrinsic would have

RalfJung · 2024-05-03T17:46:32Z

@bors r+

bors · 2024-05-03T17:46:34Z

📌 Commit 821d23b has been approved by RalfJung

It is now in the queue for this repository.

…dy, r=RalfJung Let miri and const eval execute intrinsics' fallback bodies fixes rust-lang/miri#3397 r? `@RalfJung`

…mpiler-errors Rollup of 8 pull requests Successful merges: - rust-lang#124293 (Let miri and const eval execute intrinsics' fallback bodies) - rust-lang#124418 (Use a proof tree visitor to refine the `Obligation` for error reporting in new solver) - rust-lang#124480 (Change `SIGPIPE` ui from `#[unix_sigpipe = "..."]` to `-Zon-broken-pipe=...`) - rust-lang#124648 (Trim crate graph) - rust-lang#124656 (release notes 1.78: add link to interior-mut breaking change) - rust-lang#124658 (Migrate `run-make/doctests-keep-binaries` to new rmake.rs format) - rust-lang#124681 (zkvm: fix run_tests) - rust-lang#124687 (Make `Bounds.clauses` private) r? `@ghost` `@rustbot` modify labels: rollup

compiler-errors · 2024-05-04T03:33:25Z

I believe this failed in a rollup: #124688 (comment)

compiler-errors · 2024-05-04T03:33:27Z

@bors r-

RalfJung · 2024-05-04T06:38:02Z

Yeah, const_(de)allocate need the new attribute.

I'll just quickly add them since Oli is on vacation.

RalfJung · 2024-05-04T06:41:28Z

@bors r+

bors · 2024-05-04T06:41:30Z

📌 Commit 4e97c6c has been approved by RalfJung

It is now in the queue for this repository.

…dy, r=RalfJung Let miri and const eval execute intrinsics' fallback bodies fixes rust-lang/miri#3397 r? `@RalfJung`

…iaskrgr Rollup of 6 pull requests Successful merges: - rust-lang#123356 (Reduce code size of `thread::set_current`) - rust-lang#124159 (Move thread parking to `sys::sync`) - rust-lang#124293 (Let miri and const eval execute intrinsics' fallback bodies) - rust-lang#124500 (lldb-formatters: Use StdSliceSyntheticProvider for &str) - rust-lang#124677 (Set non-leaf frame pointers on Fuchsia targets) - rust-lang#124692 (We do not coerce `&mut &mut T -> *mut mut T`) r? `@ghost` `@rustbot` modify labels: rollup

…iaskrgr Rollup of 8 pull requests Successful merges: - rust-lang#123356 (Reduce code size of `thread::set_current`) - rust-lang#124159 (Move thread parking to `sys::sync`) - rust-lang#124293 (Let miri and const eval execute intrinsics' fallback bodies) - rust-lang#124677 (Set non-leaf frame pointers on Fuchsia targets) - rust-lang#124692 (We do not coerce `&mut &mut T -> *mut mut T`) - rust-lang#124698 (Rewrite `rustdoc-determinism` test in Rust) - rust-lang#124700 (Remove an unnecessary cast) - rust-lang#124701 (Docs: suggest `uN::checked_sub` instead of check-then-unchecked) r? `@ghost` `@rustbot` modify labels: rollup

Rollup merge of rust-lang#124293 - oli-obk:miri_intrinsic_fallback_body, r=RalfJung Let miri and const eval execute intrinsics' fallback bodies fixes rust-lang/miri#3397 r? ``@RalfJung``

rustbot assigned RalfJung Apr 23, 2024

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. 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 Apr 23, 2024

oli-obk commented Apr 23, 2024

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oli-obk added 2 commits May 3, 2024 09:01

Let miri and const eval execute intrinsics' fallback bodies

351658a

Ensure miri only uses fallback bodies that have manually been vetted …

821d23b

…to preserve all UB that the native intrinsic would have

oli-obk force-pushed the miri_intrinsic_fallback_body branch from 465a755 to 821d23b Compare May 3, 2024 09:37

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 May 3, 2024

compiler-errors mentioned this pull request May 4, 2024

Rollup of 8 pull requests #124688

Closed

bors 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-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. labels May 4, 2024

mark const_(de)allocate intrinsics as suitable for Miri

4e97c6c

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-author Status: This is awaiting some action (such as code changes or more information) from the author. labels May 4, 2024

matthiaskrgr mentioned this pull request May 4, 2024

Rollup of 6 pull requests #124697

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matthiaskrgr mentioned this pull request May 4, 2024

Rollup of 8 pull requests #124703

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bors merged commit ceb7b5e into rust-lang:master May 4, 2024
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rustbot added this to the 1.80.0 milestone May 4, 2024

oli-obk deleted the miri_intrinsic_fallback_body branch May 20, 2024 07:22

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Let miri and const eval execute intrinsics' fallback bodies #124293

Let miri and const eval execute intrinsics' fallback bodies #124293

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Let miri and const eval execute intrinsics' fallback bodies #124293

Let miri and const eval execute intrinsics' fallback bodies #124293

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