Encode types in SMIR
The first commit makes sure we can actually store a Ty<'tcx> (with the lifetime) in the thread local and get it back out. The second commit then introduces types.
r? `@spastorino`
Make alias bounds sound in the new solver (take 2)
Make alias bounds sound in the new solver (in a way that does not require coinduction) by only considering them for projection types whose corresponding trait refs come from a param-env candidate.
That is, given `<T as Trait>::Assoc: Bound`, we only *really* need to consider the alias bound if `T: Trait` is satisfied via a param-env candidate. If it's instead satisfied, e.g., via an user provided impl candidate or a , then that impl should have a concrete type to which we could otherwise normalize `<T as Trait>::Assoc`, and that concrete type is then responsible to prove the `Bound` on it.
Similar consideration is given to opaque types, since we only need to consider alias bounds if we're *not* in reveal-all mode, since similarly we'd be able to reveal the opaque types and prove any bounds that way.
This does not remove that hacky "eager projection replacement" logic from object bounds, which are somewhat like alias bounds. But removing this eager normalization behavior (added in #108333) would require full coinduction to be enabled. Compare to #110628, which does remove this object-bound custom logic but requires coinduction to be sound.
r? `@lcnr`
Update cargo
10 commits in 569b648b5831ae8a515e90c80843a5287c3304ef..26b73d15a68fb94579f6d3590585ec0e9d81d3d5
2023-05-05 15:49:44 +0000 to 2023-05-09 20:28:03 +0000
- Update the semver-check script to be able to run in any directory. (rust-lang/cargo#12117)
- Semver: Note that it is not a breaking change to make an unsafe function safe (rust-lang/cargo#12116)
- Add more documentation for artifact-dependencies. (rust-lang/cargo#12110)
- changelog: move registry query fixes to the right place (rust-lang/cargo#12086)
- Disallow RUSTUP_TOOLCHAIN in the [env] table. (rust-lang/cargo#12107)
- Disallow RUSTUP_HOME in the [env] table. (rust-lang/cargo#12101)
- Fix redacting tokens in http debug. (rust-lang/cargo#12095)
- Fix self_signed_should_fail for macOS. (rust-lang/cargo#12097)
- Update git2 (rust-lang/cargo#12096)
- do not try an exponential number of package names (rust-lang/cargo#12083)
r? `@ghost`
Implement SSA-based reference propagation
Rust has a tendency to create a lot of short-lived borrows, in particular for method calls. This PR aims to remove those short-lived borrows with a const-propagation dedicated to pointers to local places.
This pass aims to transform the following pattern:
```
_1 = &raw? mut? PLACE;
_3 = *_1;
_4 = &raw? mut? *_1;
```
Into
```
_1 = &raw? mut? PLACE;
_3 = PLACE;
_4 = &raw? mut? PLACE;
```
where `PLACE` is a direct or an indirect place expression.
By removing indirection, this pass should help both dest-prop and const-prop to handle more cases.
This optimization is distinct from const-prop and dataflow const-prop since the borrow-reborrow patterns needs to preserve borrowck invariants, especially the uniqueness property of mutable references.
The pointed-to places are computed using a SSA analysis. We suppose that removable borrows are typically temporaries from autoref, so they are by construction assigned only once, and a SSA analysis is enough to catch them. For each local, we store both where and how it is used, in order to efficiently compute the all-or-nothing property. Thanks to `Derefer`, we only have to track locals, not places in general.
---
There are 3 properties that need to be upheld for this transformation to be legal:
- place constness: `PLACE` must refer to the same memory wherever it appears;
- pointer liveness: we must not introduce dereferences of dangling pointers;
- `&mut` borrow uniqueness.
## Constness
If `PLACE` is an indirect projection, if its of the form `(*LOCAL).PROJECTIONS` where:
- `LOCAL` is SSA;
- all projections in `PROJECTIONS` are constant (no dereference and no indexing).
If `PLACE` is a direct projection of a local, we consider it as constant if:
- the local is always live, or it has a single `StorageLive` that dominates all uses;
- all projections are constant.
# Liveness
When performing a substitution, we must take care not to introduce uses of dangling locals.
Using a dangling borrow is UB. Therefore, we assume that for any use of `*x`, where `x` is a borrow, the pointed-to memory is live.
Limitations:
- occurrences of `*x` in an `&raw mut? *x` are accepted;
- raw pointers are allowed to be dangling.
In those 2 case, we do not substitute anything, to be on the safe side.
**Open question:** we do not differentiate borrows of ZST and non-ZST. The UB rules may be
different depending on the layout. Having a different treatment would effectively prevent this
pass from running on polymorphic MIR, which defeats the purpose of MIR opts.
## Uniqueness
For `&mut` borrows, we also need to preserve the uniqueness property:
we must avoid creating a state where we interleave uses of `*_1` and `_2`.
To do it, we only perform full substitution of mutable borrows:
we replace either all or none of the occurrences of `*_1`.
Some care has to be taken when `_1` is copied in other locals.
```
_1 = &raw? mut? _2;
_3 = *_1;
_4 = _1
_5 = *_4
```
In such cases, fully substituting `_1` means fully substituting all of the copies.
For immutable borrows, we do not need to preserve such uniqueness property,
so we perform all the possible substitutions without removing the `_1 = &_2` statement.
Rollup of 6 pull requests
Successful merges:
- #97320 (Stabilize const_ptr_read)
- #110770 (Limit lifetime of format_args!() with inlined args.)
- #111021 (Move some tests)
- #111215 (Various changes to name resolution of anon consts)
- #111242 (support set `rpath` option for each target independently)
- #111282 (Remove some `assume`s from slice iterators that don't do anything)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Remove some `assume`s from slice iterators that don't do anything
Because the start pointer is iterators is already a `NonNull`, we emit the appropriate `!nonnull` metadata when loading the pointer to tell LLVM that it's non-null.
Probably the best way to see that it's the metadata that's important (and not the `assume`) is to observe that LLVM actually *removes* the `assume` from the optimized IR: <https://rust.godbolt.org/z/KhE6G963n>.
(I also checked that, yes, the if-not-ZST `assume` on `end` is still doing something: it's how there's a `!nonnull` metadata on its load, even though it's an ordinary raw pointer. The codegen test added in this PR fails if the other `assume` is removed.)
support set `rpath` option for each target independently
Currently the `rpath` option is a global config and it's effect on all targets.
But sometimes when developers edit the rustc code and try to release rust toolchains themselves, they may not want to add `rpath` in all targets to avoid dynamically linked shared object library privilege escalation attack.
This PR supports set `rpath` option for each target independently .
Common developers are not aware of the existence of this configuration option and do not affect the existing development process. This configuration option takes effect only after developers explicitly sets .
r? ``@albertlarsan68``
Various changes to name resolution of anon consts
Sorry this PR is kind of all over the place ^^'
Fixes#111012
- Rewrites anon const nameres to all go through `fn resolve_anon_const` explicitly instead of `visit_anon_const` to ensure that we do not accidentally resolve anon consts as if they are allowed to use generics when they aren't. Also means that we dont have bits of code for resolving anon consts that will get out of sync (i.e. legacy const generics and resolving path consts that were parsed as type arguments)
- Renames two of the `LifetimeRibKind`, `AnonConst -> ConcreteAnonConst` and `ConstGeneric -> ConstParamTy`
- Noticed while doing this that under `generic_const_exprs` all lifetimes currently get resolved to errors without any error being emitted which was causing a bunch of tests to pass without their bugs having been fixed, incidentally fixed that in this PR and marked those tests as `// known-bug:`. I'm fine to break those since `generic_const_exprs` is a very unstable incomplete feature and this PR _does_ make generic_const_exprs "less broken" as a whole, also I can't be assed to figure out what the underlying causes of all of them are. This PR reopens#77357#83993
- Changed `generics_of` to stop providing generics and predicates to enum variant discriminant anon consts since those are not allowed to use generic parameters
- Updated the error for non 'static lifetime in const arguments and the error for non 'static lifetime in const param tys to use `derive(Diagnostic)`
I have a vague idea why const-arg-in-const-arg.rs, in-closure.rs and simple.rs have started failing which is unfortunate since these were deliberately made to work, I think lifetime resolution being broken just means this regressed at some point and nobody noticed because the tests were not testing anything :( I'm fine breaking these too for the same reason as the tests for #77357#83993. I couldn't get `// known-bug` to work for these ICEs and just kept getting different stderr between CI and local `--bless` so I just removed them and will create an issue to track re-adding (and fixing) the bugs if this PR lands.
r? `@cjgillot` cc `@compiler-errors`
Revert "Populate effective visibilities in `rustc_privacy`"
This reverts commit cff85f22f5, cc #110907. It needs to be fixed, but there are too many issues being reported that I wanted to put up a revert until a proper fix can be committed.
Fixes a ton of issues where private but still reachable impls were missing during codegen:
Fixes#111320Fixes#111321Fixes#111334Fixes#111357Fixes#111368Fixes#111373Fixes#111377Fixes#111386Fixes#111387
`@bors` p=1
r? `@petrochenkov`
Update books
## rust-lang/edition-guide
1 commits in 6038be9d37d7251c966b486154af621d1794d7af..f63e578b92ff43e8cc38fcaa257b660f45c8a8c2
2023-04-26 18:40:19 UTC to 2023-04-26 18:40:19 UTC
- Fix grammar (rust-lang/edition-guide#281)
## rust-embedded/book
2 commits in 897fcf566f16bf87bf37199bdddec1801fd00532..d9eb4c3f75435b008881062ffa77bf0d1527b37d
2023-05-08 10:06:29 UTC to 2023-05-08 07:19:03 UTC
- Update Interoperability section (rust-embedded/book#351)
- Update c-with-rust.md (rust-embedded/book#352)
## rust-lang/reference
3 commits in 1f8dc727e94ae4ef92adf70df979521a1ea1143e..28dc0f3576b55f5e57c5d6e65cd68ba3161e9fd5
2023-05-06 20:25:36 UTC to 2023-05-05 01:51:00 UTC
- Add an entry for macro_rules in the "Weak keywords" lexer block (rust-lang/reference#1356)
- Document f16c target feature (rust-lang/reference#1337)
- Fix example for non-x86 targets (rust-lang/reference#1334)
## rust-lang/rust-by-example
4 commits in 31961fe22521a779070a44a8f30a2b00a20b6212..8ee9528b72b927cff8fd32346db8bbd1198816f0
2023-05-01 21:18:34 UTC to 2023-04-25 11:19:41 UTC
- add: zero padding example (rust-lang/rust-by-example#1706)
- Update reenter_question_mark.md (rust-lang/rust-by-example#1705)
- Clarify array out-of-bounds behavior. (rust-lang/rust-by-example#1703)
- Update README.md (rust-lang/rust-by-example#1704)
## rust-lang/rustc-dev-guide
2 commits in 2a5eb92197e9cf8fe91164dcbf4f9b88c0d7e73d..28dbeaf5c44bc7f5111ad412e99f2d7c5cec6c90
2023-05-02 02:20:21 UTC to 2023-04-26 19:09:10 UTC
- Add unset-exec-env compiletest header. (rust-lang/rustc-dev-guide#1682)
- extend the sixth trait system requirement (rust-lang/rustc-dev-guide#1671)
Min specialization improvements
- Don't allow specialization impls with no items, such implementations are probably not correct and only occur as mistakes in the compiler and standard library
- Fix a missing normalization call
- Adds spans for lifetime errors from overly general specializations
Closes#79457Closes#109815
Implement builtin # syntax and use it for offset_of!(...)
Add `builtin #` syntax to the parser, as well as a generic infrastructure to support both item and expression position builtin syntaxes. The PR also uses this infrastructure for the implementation of the `offset_of!` macro, added by #106934.
cc `@petrochenkov` `@DrMeepster`
cc #110680 `builtin #` tracking issue
cc #106655 `offset_of!` tracking issue
tweak "make mut" spans when assigning to locals
Work towards fixing #106857
This PR just cleans up a lot of spans which is helpful before properly fixing the issues. Best reviewed commit-by-commit.
r? `@estebank`
Tweak borrow suggestion span
Avoids a `span_to_snippet` call when we don't need to surround the expression in parentheses. The fact that the suggestion was using the whole span of the expression rather than just appending a `&` was prevented me from using `// run-rustfix` in another PR (https://github.com/rust-lang/rust/pull/110432#discussion_r1170500484).
Also some drive-by renames of functions that have been annoying me for a bit.
Add GNU Property Note
Fix#103001
Generates the missing property note:
```
Displaying notes found in: .note.gnu.property
Owner Data size Description
GNU 0x00000010 NT_GNU_PROPERTY_TYPE_0 Properties: x86 feature: IBT
```
Start using `windows sys` for Windows FFI bindings in std
Switch to using windows-sys for FFI. In order to avoid some currently contentious issues, this uses windows-bindgen to generate a smaller set of bindings instead of using the full crate.
Unlike the windows-sys crate, the generated bindings uses `*mut c_void` for handle types instead of `isize`. This to sidestep opsem concerns about mixing pointer types and integers between languages. Note that `SOCKET` remains defined as an integer but instead of being a usize, it's changed to fit the [standard library definition](a41fc00eaf/library/std/src/os/windows/raw.rs (L12-L16)):
```rust
#[cfg(target_pointer_width = "32")]
pub type SOCKET = u32;
#[cfg(target_pointer_width = "64")]
pub type SOCKET = u64;
```
The generated bindings also customizes the `#[link]` imports. I hope to switch to using raw-dylib but I don't want to tie that too closely with the switch to windows-sys.
---
Changes outside of the bindings are, for the most part, fairly minimal (e.g. some differences in `*mut` vs. `*const` or a few types differ). One issue is that our own bindings sometimes mix in higher level types, like `BorrowedHandle`. This is pretty adhoc though.
Add `#[inline]` to functions that are never called
This makes libcore binary size reduce by ~300 bytes. Not much, but these functions are never called so it doesn't make sense for them to get into the binary anyway.
Always const-evaluate the GCD in `slice::align_to_offsets`
Use an inline `const`-block to force the compiler to calculate the GCD at compile time, even in debug mode. This shouldn't affect the behavior of the program at all, but it drastically cuts down on the number of instructions emitted with optimizations disabled.
With the current implementation, a single `slice::align_to` instantiation (specifically `<[u8]>::align_to::<u128>()`) generates 676 instructions (on x86-64). Forcing the GCD computation to be const cuts it down to 327 instructions, so just over 50% less. This is obviously not representative of actual runtime gains, but I still see it as a significant win as long as it doesn't degrade compile times.
Not having to worry about LLVM const-evaluating the GCD function also allows it to use the textbook recursive euclidean algorithm instead of a much more complicated iterative implementation with multiple `unsafe`-blocks.
Rollup of 6 pull requests
Successful merges:
- #104070 (Prevent aborting guard from aborting the process in a forced unwind)
- #109410 (Introduce `AliasKind::Inherent` for inherent associated types)
- #111004 (Migrate `mir_transform` to translatable diagnostics)
- #111118 (Suggest struct when we get colon in fileds in enum)
- #111170 (Diagnostic args are still args if they're documented)
- #111354 (Fix miscompilation when calling default methods on `Future`)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Disable nrvo mir opt
See #111005 and #110902 . The ICE can definitely be hit on stable, the miscompilation I'm not sure about. The pass makes some pretty sketchy assumptions though, and we should not have it on while that's the case.
I'm not going to work on actually fixing this, it's probably not excessively difficult though.
r? rust-lang/mir-opt
Fix miscompilation when calling default methods on `Future`
In https://github.com/rust-lang/rust/issues/111264 I discovered a lingering miscompilation when calling a default method on `Future` (none currently exist). https://github.com/rust-lang/rust/pull/111279 added a debug assertion, which sadly doesn't help much since to my knowledge stage0 is not built with them enabled, and it still doesn't make default methods work like they should.
This PR fixes `resolve_instance` to resolve default methods on `Future` correctly, allowing library contributors to add `Future` combinators without running into ICEs or miscompilations. I've tested this as part of https://github.com/rust-lang/rust/pull/111347, but no test is included here (assuming that future methods include their own tests that would cover this sufficiently).
r? `@compiler-errors`
