A way forward for pointer equality in const eval by oli-obk · Pull Request #73398 · rust-lang/rust

oli-obk · 2020-06-16T08:44:20Z

r? @varkor on the first commit and @RalfJung on the second commit

src/test/ui/const-generics/raw-ptr-const-param-deref.stderr

oli-obk · 2020-06-16T12:28:01Z

r? @RalfJung for the miri changes and general scheme. I'll find someone to review everything else once we both can agree on a design

src/libcore/intrinsics.rs

src/libcore/ptr/const_ptr.rs

src/librustc_mir/transform/check_consts/ops.rs

src/test/ui/consts/const-eval/const_raw_ptr_ops.stderr

src/librustc_mir/interpret/intrinsics.rs

src/libcore/ptr/const_ptr.rs

src/librustc_mir/interpret/intrinsics.rs

src/librustc_mir/transform/check_consts/ops.rs

src/libcore/ptr/const_ptr.rs

bors · 2020-06-19T16:03:49Z

☔ The latest upstream changes (presumably #73504) made this pull request unmergeable. Please resolve the merge conflicts.

oli-obk · 2020-06-21T11:18:28Z

@bors r=varkor,RalfJung,nagisa

bors · 2020-06-21T11:18:29Z

📌 Commit e465b22 has been approved by varkor,RalfJung,nagisa

@varkor

…,RalfJung,nagisa A way forward for pointer equality in const eval r? @varkor on the first commit and @RalfJung on the second commit cc rust-lang#53020

@varkor

…,RalfJung,nagisa A way forward for pointer equality in const eval r? @varkor on the first commit and @RalfJung on the second commit cc rust-lang#53020

@varkor

…,RalfJung,nagisa A way forward for pointer equality in const eval r? @varkor on the first commit and @RalfJung on the second commit cc rust-lang#53020

@ghost

…arth Rollup of 9 pull requests Successful merges: - rust-lang#72271 (Improve compiler error message for wrong generic parameter order) - rust-lang#72493 ( move leak-check to during coherence, candidate eval) - rust-lang#73398 (A way forward for pointer equality in const eval) - rust-lang#73472 (Clean up E0689 explanation) - rust-lang#73496 (Account for multiple impl/dyn Trait in return type when suggesting `'_`) - rust-lang#73515 (Add second message for LiveDrop errors) - rust-lang#73567 (Clarify --extern documentation.) - rust-lang#73572 (Fix typos in doc comments) - rust-lang#73590 (bootstrap: no `config.toml` exists regression) Failed merges: r? @ghost

This commit includes work-arounds for the following changes in the compiler: - Raw pointers as const generic parameters are now forbidden. <rust-lang/rust#73398> This means the work-around for ICE caused by `&'static [_]` const generic parameters doesn't work anymore. An alternative work-around is yet to be implemented. - Mutable references are now forbidden in all constant contexts except for `const fn`s. <rust-lang/rust#72934> Working around this change was as easy as mechanically replacing `const` with `const fn` for most cases. The only tricky case was the definition of `id_map` inside `build!`, which is a macro meant to be called inside a `const` item. The type of `id_map` isn't explicitly specified but is rather implied by a given configuration function, so this couldn't be mechanically replaced with a `const` item. To resolve this problem, I added an explicit type to `build!`'s signature.

Fix ptr doc warnings. rust-lang#73398 added some stray backtick lines which cause warnings when the docs are built.

bjorn3 · 2020-06-27T09:32:05Z

src/libcore/slice/mod.rs


+        // While performance would suffer if `guaranteed_eq` just returned `false`
+        // for all arguments, correctness and return value of this function are not affected.
+        #[cfg(not(bootstrap))]


Why was this changed? This function is not const.

Not yet, we're working towards that. I have a local branch where I'm trying to run this in -Zunleash-the-miri-inside-of-you mode.

RalfJung · 2020-06-27T09:39:04Z

src/librustc_mir/interpret/intrinsics.rs

                let offset_ptr = ptr.ptr_wrapping_signed_offset(offset_bytes, self);
                self.write_scalar(offset_ptr, dest)?;
            }
+            sym::ptr_guaranteed_eq | sym::ptr_guaranteed_ne => {


I just realized that this implementation will also be used by Miri, which is a bug. Can we somehow make it be used only during CTCE?

doesn't miri fall back to this only if it has no own impl? So we can just give miri an impl that behaves differently.

Miri prefers the CTFE impls, to make sure we test those properly.

I am working on a PR that adds these to Miri in a way that it prefers its own impls.

Here it is: rust-lang/miri#1459

@oli-obk

…r=oli-obk Add some `const_compare_raw_pointers`-related regression tests Closes rust-lang#71381 Closes rust-lang#71382 Closes rust-lang#71611 Closes rust-lang#72352 r? @oli-obk, the author of rust-lang#73398

rust-highfive assigned varkor Jun 16, 2020

rust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Jun 16, 2020

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oli-obk force-pushed the const_raw_ptr_cmp branch from ea4d8b4 to e0c0a23 Compare June 16, 2020 10:51

varkor reviewed Jun 16, 2020

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rust-highfive assigned RalfJung and unassigned varkor Jun 16, 2020

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oli-obk force-pushed the const_raw_ptr_cmp branch from 1da7834 to 217021e Compare June 16, 2020 13:24

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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 Jun 21, 2020

Manishearth mentioned this pull request Jun 21, 2020

Rollup of 14 pull requests #73598

Closed

Manishearth mentioned this pull request Jun 22, 2020

Rollup of 13 pull requests #73604

Closed

This was referenced Jun 22, 2020

Rollup of 12 pull requests #73633

Closed

Rollup of 9 pull requests #73643

Merged

bors merged commit ae38698 into rust-lang:master Jun 23, 2020

ehuss mentioned this pull request Jun 23, 2020

Fix ptr doc warnings. #73673

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Dylan-DPC-zz pushed a commit to Dylan-DPC-zz/rust that referenced this pull request Jun 25, 2020

Rollup merge of rust-lang#73673 - ehuss:fix-ptr-docs, r=oli-obk

da1e916

Fix ptr doc warnings. rust-lang#73398 added some stray backtick lines which cause warnings when the docs are built.

Manishearth added a commit to Manishearth/rust that referenced this pull request Jun 26, 2020

Rollup merge of rust-lang#73673 - ehuss:fix-ptr-docs, r=oli-obk

57167a9

Fix ptr doc warnings. rust-lang#73398 added some stray backtick lines which cause warnings when the docs are built.

Manishearth added a commit to Manishearth/rust that referenced this pull request Jun 26, 2020

Rollup merge of rust-lang#73673 - ehuss:fix-ptr-docs, r=oli-obk

d51c959

Fix ptr doc warnings. rust-lang#73398 added some stray backtick lines which cause warnings when the docs are built.

Manishearth added a commit to Manishearth/rust that referenced this pull request Jun 26, 2020

Rollup merge of rust-lang#73673 - ehuss:fix-ptr-docs, r=oli-obk

91f8766

Fix ptr doc warnings. rust-lang#73398 added some stray backtick lines which cause warnings when the docs are built.

bjorn3 reviewed Jun 27, 2020

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oli-obk deleted the const_raw_ptr_cmp branch June 27, 2020 09:41

JohnTitor mentioned this pull request Jun 27, 2020

Add some const_compare_raw_pointers-related regression tests #73795

Merged

kanru mentioned this pull request Jul 20, 2020

Type mismatch in function arguments E0631, E0271 are falsely recognized as E0308 mismatched types #74400

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cuviper added this to the 1.46 milestone May 2, 2024

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bors commented Jun 19, 2020

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oli-obk commented Jun 16, 2020 •

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