Remove `mir::CastKind::Misc` #102675

ouz-a · 2022-10-04T20:02:47Z

As discussed in #97649 mir::CastKind::Misc is not clear, this PR addresses that by creating a new enum variant for every valid cast.

r? @oli-obk

rustbot · 2022-10-04T20:02:52Z

Some changes occurred in compiler/rustc_codegen_cranelift

cc @bjorn3

Some changes occurred in src/tools/clippy

cc @rust-lang/clippy

Some changes occurred to the CTFE / Miri engine

cc @rust-lang/miri

This PR changes MIR

cc @oli-obk, @RalfJung, @JakobDegen, @davidtwco, @celinval, @vakaras

compiler/rustc_codegen_ssa/src/mir/rvalue.rs

JakobDegen · 2022-10-05T01:08:04Z

compiler/rustc_const_eval/src/transform/validate.rs

+                    CastKind::PointerFromExposedAddress
+                    | CastKind::PointerExposeAddress
+                    | CastKind::Pointer(_) => {}
+                    _ => {


We should check that the types are as expected here (leaving out CastKind::Pointer(_) might be fine). This will probably need some deduplication with the typeck code

I am not sure what to check 😅 , with new function mir_cast_kind we already report a bug with any unexpected cast, and since we built Rvalues with that new function is a check really needed?

Yes, because MIR validation doesn't just run after MIR is built, but also after transformations that modify it

I think I modified those too, but it's better to be safe than sorry will add the checks in the next PR.

RalfJung · 2022-10-05T09:15:15Z

compiler/rustc_const_eval/src/interpret/cast.rs

@@ -42,8 +42,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                let res = self.pointer_from_exposed_address_cast(&src, cast_ty)?;
                self.write_immediate(res, dest)?;
            }
-
-            Misc => {
+            IntToInt | FloatToInt | FloatToFloat | IntToFloat | FnPtrToPtr | PtrToPtr => {
                let src = self.read_immediate(src)?;
                let res = self.misc_cast(&src, cast_ty)?;


Please add a FIXME here indicating that we shouldn't have a single misc_cast for all of them, but handle them separately.

I can do that once this get's merged. 👍

Please add the FIXME now, even if you plan to fix it immediately in a follow-up. :)

But I already did :D

Ah good, I misunderstood your comment then. :)

oli-obk · 2022-10-06T12:29:23Z

Please squash the commits. Then we can merge and leave the cleanups to follow up PRs

oli-obk · 2022-10-06T18:03:07Z

@bors r+

bors · 2022-10-06T18:03:09Z

📌 Commit d59c7ff has been approved by oli-obk

It is now in the queue for this repository.

scottmcm · 2022-10-07T00:04:25Z

compiler/rustc_middle/src/mir/syntax.rs

+    FloatToInt,
+    FloatToFloat,
+    IntToFloat,
+    PtrToPtr,


Non-blocking request from the peanut gallery: It's not obvious to me how PtrToPtr differs from things in Pointer(_). Could you please put some doc-comments on the new variants?

"FIXME: Pointer(_) is legacy code and should be removed. Please submit a PR if you feel inclined." 🙃

I haven't investigated the behavior of Pointer(_) but old code did it like the below, and some Ptr to Ptr casts went through CastKind::Misc e.g code in src/test/ui/simd/intrinsic/ptr-cast.rs. However, I could also investigate what Pointer(_) is actually doing in the next PR.

(_, _) => CastKind::Misc,

Remove `mir::CastKind::Misc` As discussed in rust-lang#97649 `mir::CastKind::Misc` is not clear, this PR addresses that by creating a new enum variant for every valid cast. r? `@oli-obk`

Remove `mir::CastKind::Misc` As discussed in rust-lang#97649 `mir::CastKind::Misc` is not clear, this PR addresses that by creating a new enum variant for every valid cast. r? ``@oli-obk``

Remove `mir::CastKind::Misc` As discussed in rust-lang#97649 `mir::CastKind::Misc` is not clear, this PR addresses that by creating a new enum variant for every valid cast. r? ```@oli-obk```

…iaskrgr Rollup of 8 pull requests Successful merges: - rust-lang#101520 (Allow transmutes between the same types after erasing lifetimes) - rust-lang#102675 (Remove `mir::CastKind::Misc`) - rust-lang#102778 (Fix MIR inlining of asm_unwind) - rust-lang#102785 (Remove `DefId` from some `SelectionCandidate` variants) - rust-lang#102788 (Update rustc-dev-guide) - rust-lang#102789 (Update browser UI test version) - rust-lang#102797 (rustdoc: remove no-op CSS `.rightside { position: initial }`) - rust-lang#102798 (rustdoc: add main-heading and example-wrap link CSS to big selector) Failed merges: r? `@ghost` `@rustbot` modify labels: rollup

Remove `mir::CastKind::Misc` As discussed in rust-lang#97649 `mir::CastKind::Misc` is not clear, this PR addresses that by creating a new enum variant for every valid cast. r? ````@oli-obk````

Remove misc_cast and validate types when casting Continuing our work in rust-lang#102675 r? `@oli-obk`

Remove misc_cast and validate types when casting Continuing our work in rust-lang#102675 r? ``@oli-obk``

Remove misc_cast and validate types when casting Continuing our work in rust-lang#102675 r? ```@oli-obk```

Remove misc_cast and validate types when casting Continuing our work in rust-lang#102675 r? ````@oli-obk````

rust-highfive assigned oli-obk Oct 4, 2022

rustbot added the T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. label Oct 4, 2022

rust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Oct 4, 2022

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JakobDegen reviewed Oct 5, 2022

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Remove mir::CastKind::Misc

d59c7ff

ouz-a force-pushed the mir-technical-debt branch from db0d68d to d59c7ff Compare October 6, 2022 12:32

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 Oct 6, 2022

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Dylan-DPC mentioned this pull request Oct 8, 2022

Rollup of 7 pull requests #102801

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matthiaskrgr mentioned this pull request Oct 8, 2022

Rollup of 7 pull requests #102802

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Dylan-DPC mentioned this pull request Oct 8, 2022

Rollup of 7 pull requests #102803

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matthiaskrgr mentioned this pull request Oct 8, 2022

Rollup of 8 pull requests #102809

Merged

bors merged commit c731646 into rust-lang:master Oct 8, 2022

rustbot added this to the 1.66.0 milestone Oct 8, 2022

tedinski mentioned this pull request Oct 14, 2022

Update Kani to Rust nightly-2022-10-11 model-checking/kani#1788

Merged

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ouz-a mentioned this pull request Oct 16, 2022

Remove misc_cast and validate types when casting #103122

Merged

Dylan-DPC added a commit to Dylan-DPC/rust that referenced this pull request Oct 22, 2022

Rollup merge of rust-lang#103122 - ouz-a:mir-technical-debt, r=oli-obk

24d17ef

Remove misc_cast and validate types when casting Continuing our work in rust-lang#102675 r? `@oli-obk`

Dylan-DPC added a commit to Dylan-DPC/rust that referenced this pull request Oct 24, 2022

Rollup merge of rust-lang#103122 - ouz-a:mir-technical-debt, r=oli-obk

60f3f07

Remove misc_cast and validate types when casting Continuing our work in rust-lang#102675 r? `@oli-obk`

Dylan-DPC added a commit to Dylan-DPC/rust that referenced this pull request Oct 25, 2022

Rollup merge of rust-lang#103122 - ouz-a:mir-technical-debt, r=oli-obk

1c8201c

Remove misc_cast and validate types when casting Continuing our work in rust-lang#102675 r? ``@oli-obk``

Dylan-DPC added a commit to Dylan-DPC/rust that referenced this pull request Oct 25, 2022

Rollup merge of rust-lang#103122 - ouz-a:mir-technical-debt, r=oli-obk

ee05439

Remove misc_cast and validate types when casting Continuing our work in rust-lang#102675 r? ```@oli-obk```

Dylan-DPC added a commit to Dylan-DPC/rust that referenced this pull request Oct 25, 2022

Rollup merge of rust-lang#103122 - ouz-a:mir-technical-debt, r=oli-obk

8ba2a65

Remove misc_cast and validate types when casting Continuing our work in rust-lang#102675 r? ````@oli-obk````

Aaron1011 pushed a commit to Aaron1011/rust that referenced this pull request Jan 6, 2023

Rollup merge of rust-lang#103122 - ouz-a:mir-technical-debt, r=oli-obk

9e2be77

Remove misc_cast and validate types when casting Continuing our work in rust-lang#102675 r? ````@oli-obk````

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Remove `mir::CastKind::Misc` #102675

Remove `mir::CastKind::Misc` #102675

ouz-a commented Oct 4, 2022

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Remove mir::CastKind::Misc #102675

Remove mir::CastKind::Misc #102675

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Remove `mir::CastKind::Misc` #102675

Remove `mir::CastKind::Misc` #102675