Miri: fix error on dangling pointer inbounds offset
We used to claim that the pointer was "dereferenced", but that is just not true.
Can be reviewed commit-by-commit. The first commit is an unrelated rename that didn't seem worth splitting into its own PR.
r? `@oli-obk`
Turns out opaque types can have hidden types registered during mir validation
See the newly added test's documentation for an explanation.
fixes#114121
Replace in-tree `rustc_apfloat` with the new version of the crate
Replace the in-tree version of `rustc_apfloat` with the new version of the crate which has been correctly licensed. The new crate incorporates upstream changes from LLVM since the original port was done including many correctness fixes and has been extensively fuzz tested to validate correctness.
Fixes#100233Fixes#102403Fixes#113407Fixes#113409Fixes#55993Fixes#93224Closes#93225Closes#109573
interpret: make read/write methods generic
Instead of always having to call `into()` to convert things to `PlaceTy`/`OpTy`, make the relevant methods generic. This also means that when we read from an `MPlaceTy`, we avoid creating an intermediate `PlaceTy`.
This makes it feasible to remove the `Copy` from `MPlaceTy`. All the other `*Ty` interpreter types already had their `Copy` removed a while ago so this is only consistent. (And in fact we had one function that accidentally took `MPlaceTy` instead of `&MPlaceTy`.)
Double check that hidden types match the expected hidden type
Fixes https://github.com/rust-lang/rust/issues/113278 specifically, but I left a TODO for where we should also add some hardening.
It feels a bit like papering over the issue, but at least this way we don't get unsoundness, but just surprising errors. Errors will be improved and given spans before this PR lands.
r? `@compiler-errors` `@lcnr`
Normalize the RHS of an `Unsize` goal in the new solver
`Unsize` goals are... tricky. Not only do they structurally match on their self type, but they're also structural on their other type parameter. I'm pretty certain that it is both incomplete and also just plain undesirable to not consider normalizing the RHS of an unsize goal. More practically, I'd like for this code to work:
```rust
trait A {}
trait B: A {}
impl A for usize {}
impl B for usize {}
trait Mirror {
type Assoc: ?Sized;
}
impl<T: ?Sized> Mirror for T {
type Assoc = T;
}
fn main() {
// usize: Unsize<dyn B>
let x = Box::new(1usize) as Box<<dyn B as Mirror>::Assoc>;
// dyn A: Unsize<dyn B>
let y = x as Box<<dyn A as Mirror>::Assoc>;
}
```
---
In order to achieve this, we add `EvalCtxt::normalize_non_self_ty` (naming modulo bikeshedding), which *must* be used for all non-self type arguments that are structurally matched in candidate assembly. Currently this is only necessary for `Unsize`'s argument, but I could see future traits requiring this (hopefully rarely) in the future. It uses `repeat_while_none` to limit infinite looping, and normalizes the self type until it is no longer an alias.
Also, we need to fix feature gate detection for `trait_upcasting` and `unsized_tuple_coercion` when HIR typeck has unnormalized types. We can do that by checking the `ImplSource` returned by selection, which necessitates adding a new impl source for tuple upcasting.
interpret: Unify projections for MPlaceTy, PlaceTy, OpTy
For ~forever, we didn't really have proper shared code for handling projections into those three types. This is mostly because `PlaceTy` projections require `&mut self`: they might have to `force_allocate` to be able to represent a project part-way into a local.
This PR finally fixes that, by enhancing `Place::Local` with an `offset` so that such an optimized place can point into a part of a place without having requiring an in-memory representation. If we later write to that place, we will still do `force_allocate` -- for now we don't have an optimized path in `write_immediate` that would avoid allocation for partial overwrites of immediately stored locals. But in `write_immediate` we have `&mut self` so at least this no longer pollutes all our type signatures.
(Ironically, I seem to distantly remember that many years ago, `Place::Local` *did* have an `offset`, and I removed it to simplify things. I guess I didn't realize why it was so useful... I am also not sure if this was actually used to achieve place projection on `&self` back then.)
The `offset` had type `Option<Size>`, where `None` represent "no projection was applied". This is needed because locals *can* be unsized (when they are arguments) but `Place::Local` cannot store metadata: if the offset is `None`, this refers to the entire local, so we can use the metadata of the local itself (which must be indirect); if a projection gets applied, since the local is indirect, it will turn into a `Place::Ptr`. (Note that even for indirect locals we can have `Place::Local`: when the local appears in MIR, we always start with `Place::Local`, and only check `frame.locals` later. We could eagerly normalize to `Place::Ptr` but I don't think that would actually simplify things much.)
Having done all that, we can finally properly abstract projections: we have a new `Projectable` trait that has the basic methods required for projecting, and then all projection methods are implemented for anything that implements that trait. We can even implement it for `ImmTy`! (Not that we need that, but it seems neat.) The visitor can be greatly simplified; it doesn't need its own trait any more but it can use the `Projectable` trait. We also don't need the separate `Mut` visitor any more; that was required only to reflect that projections on `PlaceTy` needed `&mut self`.
It is possible that there are some more `&mut self` that can now become `&self`... I guess we'll notice that over time.
r? `@oli-obk`
Reuse the MIR validator for MIR inlining
Instead of having the inliner home-cook its own validation, we just check that the substituted MIR body passes the regular validation.
The MIR validation is first split in two: control flow validation (MIR syntax and CFG invariants) and type validation (subtyping relationship in assignments and projections). Only the latter can be affected by instantiating type parameters.
clarify MIR uninit vs LLVM undef/poison
In [this LLVM discussion](https://discourse.llvm.org/t/rfc-load-instruction-uninitialized-memory-semantics/67481) I learned that mapping our uninitialized memory in MIR to poison in LLVM would be quite problematic due to the lack of a byte type. I am not sure where to write down this insight but this seems like a reasonable start.
miri will report an UB when calling a function that has a `#[target_feature(enable = ...)]` attribute is called and the required feature is not available.
"Available features" are the same that `is_x86_feature_detected!` (or equivalent) reports to be available during miri execution (which can be enabled or disabled with the `-C target-feature` flag).
Rename `adjustment::PointerCast` and variants using it to `PointerCoercion`
It makes it sounds like the `ExprKind` and `Rvalue` are supposed to represent all pointer related casts, when in reality their just used to share a little enum variants. Make it clear there these are only coercions and that people who see this and think "why are so many pointer related casts not in these variants" aren't insane.
This enum was added in #59987. I'm not sure whether the variant sharing is actually worth it, but this at least makes it less confusing.
r? oli-obk
It makes it sound like the `ExprKind` and `Rvalue` are supposed to represent all pointer related
casts, when in reality their just used to share a some enum variants. Make it clear there these
are only coercion to make it clear why only some pointer related "casts" are in the enum.
Split `SelectionContext::select` into fns that take a binder and don't
*most* usages of `SelectionContext::select` don't need to use a binder, but wrap them in a dummy because of the signature. Let's split this out into `SelectionContext::{select,poly_select}` and limit the usages of the latter.
Right now, we only have 3 places where we're calling `poly_select` -- fulfillment, internally within the old solver, and the auto-trait finder.
r? `@lcnr`
Move `TyCtxt::mk_x` to `Ty::new_x` where applicable
Part of rust-lang/compiler-team#616
turns out there's a lot of places we construct `Ty` this is a ridiculously huge PR :S
r? `@oli-obk`
Make simd_shuffle_indices use valtrees
This removes the second-to-last user of the `destructure_mir_constant` query. So in a follow-up we can remove the query and just move the query provider function directly into pretty printing (which is the last user).
cc `@rust-lang/clippy` there's a small functional change, but I think it is correct?
Switch the BB CFG cache from postorder to RPO
The `BasicBlocks` CFG cache is interesting:
- it stores a postorder, but `traversal::postorder` doesn't use it
- `traversal::reverse_postorder` does traverse the postorder cache backwards
- we do more RPO traversals than postorder traversals (around 20x on the perf.rlo benchmarks IIRC) but it's not cached
- a couple places here and there were manually reversing the non-cached postorder traversal
This PR switches the order of the cache, and makes a bit more use of it. This is a tiny win locally, but it's also for consistency and aesthetics.
r? `@ghost`
Take MIR dataflow analyses by mutable reference
The main motivation here is any analysis requiring dynamically sized scratch memory to work. One concrete example would be pointer target tracking, where tracking the results of a dereference can result in multiple possible targets. This leads to processing multi-level dereferences requiring the ability to handle a changing number of potential targets per step. A (simplified) function for this would be `fn apply_deref(potential_targets: &mut Vec<Target>)` which would use the scratch space contained in the analysis to send arguments and receive the results.
The alternative to this would be to wrap everything in a `RefCell`, which is what `MaybeRequiresStorage` currently does. This comes with a small perf cost and loses the compiler's guarantee that we don't try to take multiple borrows at the same time.
For the implementation:
* `AnalysisResults` is an unfortunate requirement to avoid an unconstrained type parameter error.
* `CloneAnalysis` could just be `Clone` instead, but that would result in more work than is required to have multiple cursors over the same result set.
* `ResultsVisitor` now takes the results type on in each function as there's no other way to have access to the analysis without cloning it. This could use an associated type rather than a type parameter, but the current approach makes it easier to not care about the type when it's not necessary.
* `MaybeRequiresStorage` now no longer uses a `RefCell`, but the graphviz formatter now does. It could be removed, but that would require even more changes and doesn't really seem necessary.
- Switch TypeId to 128 bits
- Hack around the fact that tracing-subscriber dislikes how TypeId is hashed
- Remove lowering of type_id128 from rustc_codegen_llvm
- Remove unnecessary `type_id128` intrinsic (just change return type of `type_id`)
- Only hash the lower 64 bits of the TypeId
- Reword comment
Replace const eval limit by a lint and add an exponential backoff warning
The lint triggers at the first power of 2 that comes after 1 million function calls or traversed back-edges (takes less than a second on usual programs). After the first emission, an unsilenceable warning is repeated at every following power of 2 terminators, causing it to get reported less and less the longer the evaluation runs.
cc `@rust-lang/wg-const-eval`
fixes#93481closes#67217
Only rewrite valtree-constants to patterns and keep other constants opaque
Now that we can reliably fall back to comparing constants with `PartialEq::eq` to the match scrutinee, we can
1. eagerly try to convert constants to valtrees
2. then deeply convert the valtree to a pattern
3. if the to-valtree conversion failed, create an "opaque constant" pattern.
This PR specifically avoids any behavioral changes or major cleanups. What we can now do as follow ups is
* move the two remaining call sites to `destructure_mir_constant` off that query
* make valtree to pattern conversion infallible
* this needs to be done after careful analysis of the effects. There may be user visible changes from that.
based on https://github.com/rust-lang/rust/pull/111768
change `BorrowKind::Unique` to be a mutating `PlaceContext`
fixes#112056
I believe that `BorrowKind::Unique` is a footgun in general, so I added a FIXME and opened https://github.com/rust-lang/rust/issues/112072. This is a bit too involved for this PR though.
Ensure Fluent messages are in alphabetical order
Fixes#111847
This adds a tidy check to ensure Fluent messages are in alphabetical order, as well as sorting all existing messages. I think the error could be worded better, would appreciate suggestions.
<details>
<summary>Script used to sort files</summary>
```py
import sys
import re
fn = sys.argv[1]
with open(fn, 'r') as f:
data = f.read().split("\n")
chunks = []
cur = ""
for line in data:
if re.match(r"^([a-zA-Z0-9_]+)\s*=\s*", line):
chunks.append(cur)
cur = ""
cur += line + "\n"
chunks.append(cur)
chunks.sort()
with open(fn, 'w') as f:
f.write(''.join(chunks).strip("\n\n") + "\n")
```
</details>
