Implement rustc part of RFC 3127 trim-paths
This PR implements (or at least tries to) [RFC 3127 trim-paths](https://github.com/rust-lang/rust/issues/111540), the rustc part. That is `-Zremap-path-scope` with all of it's components/scopes.
`@rustbot` label: +F-trim-paths
Remove lots of generics from `ty::print`
All of these generics mostly resolve to the same thing, which means we can remove them, greatly simplifying the types involved in pretty printing and unlocking another simplification (that is not performed in this PR): Using `&mut self` instead of passing `self` through the return type.
cc `@eddyb` you probably know why it's like this, just checking in and making sure I didn't do anything bad
r? oli-obk
These are `Self` in almost all printers except one, which can just store
the state as a field instead. This simplifies the printer and allows for
further simplifications, for example using `&mut self` instead of
passing around the printer.
don't UB on dangling ptr deref, instead check inbounds on projections
This implements https://github.com/rust-lang/reference/pull/1387 in Miri. See that PR for what the change is about.
Detecting dangling references in `let x = &...;` is now done by validity checking only, so some tests need to have validity checking enabled. There is no longer inherently a "nodangle" check in evaluating the expression `&*ptr` (aside from the aliasing model).
r? `@oli-obk`
Based on:
- https://github.com/rust-lang/reference/pull/1387
- https://github.com/rust-lang/rust/pull/115524
interpret: clean up AllocBytes
Fixes https://github.com/rust-lang/miri/issues/2836
Nothing has moved here in half a year, so let's just remove these unused stubs -- they need a proper re-design anyway.
r? `@oli-obk`
It's a better name, and lets "active features" refer to the features
that are active in a particular program, due to being declared or
enabled by the edition.
The commit also renames `Features::enabled` as `Features::active` to
match this; I changed my mind and have decided that "active" is a little
better thatn "enabled" for this, particularly because a number of
pre-existing comments use "active" in this way.
Finally, the commit renames `Status::Stable` as `Status::Accepted`, to
match `ACCEPTED_FEATURES`.
Format all the let-chains in compiler crates
Since rust-lang/rustfmt#5910 has landed, soon we will have support for formatting let-chains (as soon as rustfmt syncs and beta gets bumped).
This PR applies the changes [from master rustfmt to rust-lang/rust eagerly](https://rust-lang.zulipchat.com/#narrow/stream/122651-general/topic/out.20formatting.20of.20prs/near/374997516), so that the next beta bump does not have to deal with a 200+ file diff and can remain concerned with other things like `cfg(bootstrap)` -- #113637 was a pain to land, for example, because of let-else.
I will also add this commit to the ignore list after it has landed.
The commands that were run -- I'm not great at bash-foo, but this applies rustfmt to every compiler crate, and then reverts the two crates that should probably be formatted out-of-tree.
```
~/rustfmt $ ls -1d ~/rust/compiler/* | xargs -I@ cargo run --bin rustfmt -- `@/src/lib.rs` --config-path ~/rust --edition=2021 # format all of the compiler crates
~/rust $ git checkout HEAD -- compiler/rustc_codegen_{gcc,cranelift} # revert changes to cg-gcc and cg-clif
```
cc `@rust-lang/rustfmt`
r? `@WaffleLapkin` or `@Nilstrieb` who said they may be able to review this purely mechanical PR :>
cc `@Mark-Simulacrum` and `@petrochenkov,` who had some thoughts on the order of operations with big formatting changes in https://github.com/rust-lang/rust/pull/95262#issue-1178993801. I think the situation has changed since then, given that let-chains support exists on master rustfmt now, and I'm fairly confident that this formatting PR should land even if *bootstrap* rustfmt doesn't yet format let-chains in order to lessen the burden of the next beta bump.
const_eval: allow function pointer signatures containing &mut T in const contexts
potentially fixes#114994
We utilize a `TypeVisitor` here in order to more easily handle control flow.
- In the event the typekind the Visitor sees is a function pointer, we skip over it
- However, otherwise we do one of two things:
- If we find a mutable reference, check it, then continue visiting types
- If we find any other type, continue visiting types
This means we will check if the function pointer _itself_ is mutable, but not if any of the types _within_ are.
const-eval: make misalignment a hard error
It's been a future-incompat error (showing up in cargo's reports) since https://github.com/rust-lang/rust/pull/104616, Rust 1.68, released in March. That should be long enough.
The question for the lang team is simply -- should we move ahead with this, making const-eval alignment failures a hard error? (It turns out some of them accidentally already were hard errors since #104616. But not all so this is still a breaking change. Crater found no regression.)
miri: make NaN generation non-deterministic
This implements the [LLVM semantics for NaN generation](https://llvm.org/docs/LangRef.html#behavior-of-floating-point-nan-values). I will soon submit an RFC to make this also officially the Rust semantics, but it has been our de-facto semantics for a long time so there's no reason Miri has to wait for that RFC. This PR just better aligns Miri with codegen.
This PR does that just for the operations that have MIR primitives; a future PR will adjust the intrinsics.
Show more information when multiple `impl`s apply
- When there are `impl`s without type params, show only those (to avoid showing overly generic `impl`s).
```
error[E0283]: type annotations needed
--> $DIR/multiple-impl-apply.rs:34:9
|
LL | let y = x.into();
| ^ ---- type must be known at this point
|
note: multiple `impl`s satisfying `_: From<Baz>` found
--> $DIR/multiple-impl-apply.rs:14:1
|
LL | impl From<Baz> for Bar {
| ^^^^^^^^^^^^^^^^^^^^^^
...
LL | impl From<Baz> for Foo {
| ^^^^^^^^^^^^^^^^^^^^^^
= note: required for `Baz` to implement `Into<_>`
help: consider giving `y` an explicit type
|
LL | let y: /* Type */ = x.into();
| ++++++++++++
```
- Lower the importance of `T: Sized`, `T: WellFormed` and coercion errors, to prioritize more relevant errors. The pre-existing deduplication logic deals with hiding redundant errors better that way, and we show errors with more metadata that is useful to the user.
- Show `<SelfTy as Trait>::assoc_fn` suggestion in more cases.
```
error[E0790]: cannot call associated function on trait without specifying the corresponding `impl` type
--> $DIR/cross-return-site-inference.rs:38:16
|
LL | return Err(From::from("foo"));
| ^^^^^^^^^^ cannot call associated function of trait
|
help: use a fully-qualified path to a specific available implementation
|
LL | return Err(</* self type */ as From>::from("foo"));
| +++++++++++++++++++ +
```
Fix#88284.
In `report_fullfillment_errors` push back `T: Sized`, `T: WellFormed`
and coercion errors to the end of the list. The pre-existing
deduplication logic eliminates redundant errors better that way, keeping
the resulting output with fewer errors than before, while also having
more detail.
Rollup of 5 pull requests
Successful merges:
- #115863 (Add check_unused_messages in tidy)
- #116210 (Ensure that `~const` trait bounds on associated functions are in const traits or impls)
- #116358 (Rename both of the `Match` relations)
- #116371 (Remove unused features from `rustc_llvm`.)
- #116374 (Print normalized ty)
r? `@ghost`
`@rustbot` modify labels: rollup
Partially outline code inside the panic! macro
This outlines code inside the panic! macro in some cases. This is split out from https://github.com/rust-lang/rust/pull/115562 to exclude changes to rustc.
interpret: more consistently use ImmTy in operators and casts
The diff in src/tools/miri/src/shims/x86/sse2.rs should hopefully suffice to explain why this is nicer. :)
rename mir::Constant -> mir::ConstOperand, mir::ConstKind -> mir::Const
Also, be more consistent with the `to/eval_bits` methods... we had some that take a type and some that take a size, and then sometimes the one that takes a type is called `bits_for_ty`.
Turns out that `ty::Const`/`mir::ConstKind` carry their type with them, so we don't need to even pass the type to those `eval_bits` functions at all.
However this is not properly consistent yet: in `ty` we have most of the methods on `ty::Const`, but in `mir` we have them on `mir::ConstKind`. And indeed those two types are the ones that correspond to each other. So `mir::ConstantKind` should actually be renamed to `mir::Const`. But what to do with `mir::Constant`? It carries around a span, that's really more like a constant operand that appears as a MIR operand... it's more suited for `syntax.rs` than `consts.rs`, but the bigger question is, which name should it get if we want to align the `mir` and `ty` types? `ConstOperand`? `ConstOp`? `Literal`? It's not a literal but it has a field called `literal` so it would at least be consistently wrong-ish...
``@oli-obk`` any ideas?
move required_consts check to general post-mono-check function
This factors some code that is common between the interpreter and the codegen backends into shared helper functions. Also as a side-effect the interpreter now uses the same `eval` functions as everyone else to get the evaluated MIR constants.
Also this is in preparation for another post-mono check that will be needed for (the current hackfix for) https://github.com/rust-lang/rust/issues/115709: ensuring that all locals are dynamically sized.
I didn't expect this to change diagnostics, but it's just cycle errors that change.
r? `@oli-obk`
Rollup of 6 pull requests
Successful merges:
- #115736 (Remove `verbose_generic_activity_with_arg`)
- #115771 (cleanup leftovers of const_err lint)
- #115798 (add helper method for finding the one non-1-ZST field)
- #115812 (Merge settings.css into rustdoc.css)
- #115815 (fix: return early when has tainted in mir pass)
- #115816 (Disabled socketpair for Vita)
r? `@ghost`
`@rustbot` modify labels: rollup
cleanup leftovers of const_err lint
Some code / comments seem to not have been updated when const_err was turned into a hard error, so we can do a bit of cleanup here.
r? `@oli-obk`
Read from non-scalar constants and statics in dataflow const-prop
DataflowConstProp is designed to handle scalar values. When MIR features an assignment from a non-scalar constant, we need to manually decompose it into the custom state space.
This PR tweaks interpreter callbacks to allow reusing `eval_mir_constant` without having a stack frame to get a span from.
r? `@oli-obk`
cc `@jachris`
miri: catch function calls where the argument is caller-invalid / the return value callee-invalid
When doing a type-changing copy, we must validate the data both at the old and new type.
Fixes https://github.com/rust-lang/miri/issues/3017
miri ABI compatibility check: accept u32 and i32
If only the sign differs, then surely these types are compatible. (We do still check that `arg_ext` is the same, just in case.)
Also I made it so that the ABI check must *imply* that size and alignment are the same, but it doesn't actively check that itself. With how crazy ABI constraints get, having equal size and align really shouldn't be used as a signal for anything I think...
Add MIR validation for unwind out from nounwind functions + fixes to make validation pass
`@Nilstrieb` This is the MIR validation you asked in https://github.com/rust-lang/rust/pull/112403#discussion_r1222739722.
Two passes need to be fixed to get the validation to pass:
* `RemoveNoopLandingPads` currently unconditionally introduce a resume block (even there is none to begin with!), changed to not do that
* Generator state transform introduces a `assert` which may unwind, and its drop elaboration also introduces many new `UnwindAction`s, so in this case run the AbortUnwindingCalls after the transformation.
I believe this PR should also fixRust-for-Linux/linux#1016, cc `@ojeda`
r? `@Nilstrieb`
Add a new `compare_bytes` intrinsic instead of calling `memcmp` directly
As discussed in #113435, this lets the backends be the place that can have the "don't call the function if n == 0" logic, if it's needed for the target. (I didn't actually *add* those checks, though, since as I understood it we didn't actually need them on known targets?)
Doing this also let me make it `const` (unstable), which I don't think `extern "C" fn memcmp` can be.
cc `@RalfJung` `@Amanieu`
Add documentation to has_deref
Documentation of `has_deref` needed some polish to be more clear about where it should be used and what's it's purpose.
cc https://github.com/rust-lang/rust/issues/114401
r? `@RalfJung`
const validation: point at where we found a pointer but expected an integer
Instead of validation just printing "unable to turn pointer into bytes", make this a regular validation error that says where in the value the bad pointer was found. Also distinguish "expected integer, got pointer" from "expected pointer, got partial pointer or mix of pointers".
To avoid duplicating things too much I refactored the diagnostics for validity a bit, so that "got uninit, expected X" and "got pointer, expected X" can share the "X" part. Also all the errors emitted for validation are now grouped under `const_eval_validation` so that they are in a single group in the ftl file.
r? `@oli-obk`
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>
Pretty-print inherent projections correctly
Previously, we were trying to pretty-print inherent projections with `Printer::print_def_path` which is incorrect since
it expects the substitutions to be of a certain format (parents substs followed by own substs) which doesn't hold for
inherent projections (self type subst followed by own substs).
Now we print inherent projections manually.
Fixes#111390.
Fixes#111397.
Lacking tests! Is there a test suite / compiletest flags for the pretty-printer? In most if not all cases,
inherent projections are normalized away before they get the chance to appear in diagnostics.
If I were to create regression tests for linked issues, they would need to be `mir-opt` tests to exercise
`-Zdump-mir=all` (right?) which doesn't feel quite adequate to me.
`@rustbot` label F-inherent_associated_types
Suppress "erroneous constant used" for constants tainted by errors
When constant evaluation fails because its MIR is tainted by errors,
suppress note indicating that erroneous constant was used, since those
errors have to be fixed regardless of the constant being used or not.
Fixes#110891.
Move expansion of query macros in rustc_middle to rustc_middle::query
This moves the expansion of `define_callbacks!` and `define_feedable!` from `rustc_middle::ty::query` to `rustc_middle::query`.
This means that types used in queries are both imported and used in `rustc_middle::query` instead of being split between these modules. It also decouples `rustc_middle::ty::query` further from `rustc_middle` which is helpful since we want to move `rustc_middle::ty::query` to the query system crates.
When constant evaluation fails because its MIR is tainted by errors,
suppress note indicating that erroneous constant was used, since those
errors have to be fixed regardless of the constant being used or not.
Change the immediate_dominator return type to Option, and use None to
indicate that node has no immediate dominator.
Also fix the issue where the start node would be returned as its own
immediate dominator.
Currently a `{D,Subd}iagnosticMessage` can be created from any type that
impls `Into<String>`. That includes `&str`, `String`, and `Cow<'static,
str>`, which are reasonable. It also includes `&String`, which is pretty
weird, and results in many places making unnecessary allocations for
patterns like this:
```
self.fatal(&format!(...))
```
This creates a string with `format!`, takes a reference, passes the
reference to `fatal`, which does an `into()`, which clones the
reference, doing a second allocation. Two allocations for a single
string, bleh.
This commit changes the `From` impls so that you can only create a
`{D,Subd}iagnosticMessage` from `&str`, `String`, or `Cow<'static,
str>`. This requires changing all the places that currently create one
from a `&String`. Most of these are of the `&format!(...)` form
described above; each one removes an unnecessary static `&`, plus an
allocation when executed. There are also a few places where the existing
use of `&String` was more reasonable; these now just use `clone()` at
the call site.
As well as making the code nicer and more efficient, this is a step
towards possibly using `Cow<'static, str>` in
`{D,Subd}iagnosticMessage::{Str,Eager}`. That would require changing
the `From<&'a str>` impls to `From<&'static str>`, which is doable, but
I'm not yet sure if it's worthwhile.
Don't validate constants in const propagation
Validation is neither necessary nor desirable.
The constant validation is already omitted at mir-opt-level >= 3, so there there are not changes in MIR test output (the propagation of invalid constants is covered by an existing test in tests/mir-opt/const_prop/invalid_constant.rs).
Tweak await span to not contain dot
Fixes a discrepancy between method calls and await expressions where the latter are desugared to have a span that *contains* the dot (i.e. `.await`) but method call identifiers don't contain the dot. This leads to weird suggestions suggestions in borrowck -- see linked issue.
Fixes#110761
This mostly touches a bunch of tests to tighten their `await` span.
More core::fmt::rt cleanup.
- Removes the `V1` suffix from the `Argument` and `Flag` types.
- Moves more of the format_args lang items into the `core::fmt::rt` module. (The only remaining lang item in `core::fmt` is `Arguments` itself, which is a public type.)
Part of https://github.com/rust-lang/rust/issues/99012
Follow-up to https://github.com/rust-lang/rust/pull/110616
They're semantically the same, so this means the backends don't need to handle the intrinsic and means fewer MIR basic blocks in pointer arithmetic code.
Evaluate place expression in `PlaceMention`
https://github.com/rust-lang/rust/pull/102256 introduces a `PlaceMention(place)` MIR statement which keep trace of `let _ = place` statements from surface rust, but without semantics.
This PR proposes to change the behaviour of `let _ =` patterns with respect to the borrow-checker to verify that the bound place is live.
Specifically, consider this code:
```rust
let _ = {
let a = 5;
&a
};
```
This passes borrowck without error on stable. Meanwhile, replacing `_` by `_: _` or `_p` errors with "error[E0597]: `a` does not live long enough", [see playground](https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=c448d25a7c205dc95a0967fe96bccce8).
This PR *does not* change how `_` patterns behave with respect to initializedness: it remains ok to bind a moved-from place to `_`.
The relevant test is `tests/ui/borrowck/let_underscore_temporary.rs`. Crater check found no regression.
For consistency, this PR changes miri to evaluate the place found in `PlaceMention`, and report eventual dangling pointers found within it.
r? `@RalfJung`
Add offset_of! macro (RFC 3308)
Implements https://github.com/rust-lang/rfcs/pull/3308 (tracking issue #106655) by adding the built in macro `core::mem::offset_of`. Two of the future possibilities are also implemented:
* Nested field accesses (without array indexing)
* DST support (for `Sized` fields)
I wrote this a few months ago, before the RFC merged. Now that it's merged, I decided to rebase and finish it.
cc `@thomcc` (RFC author)
Add `rustc_fluent_macro` to decouple fluent from `rustc_macros`
Fluent, with all the icu4x it brings in, takes quite some time to compile. `fluent_messages!` is only needed in further downstream rustc crates, but is blocking more upstream crates like `rustc_index`. By splitting it out, we allow `rustc_macros` to be compiled earlier, which speeds up `x check compiler` by about 5 seconds (and even more after the needless dependency on `serde_json` is removed from `rustc_data_structures`).
Encode hashes as bytes, not varint
In a few places, we store hashes as `u64` or `u128` and then apply `derive(Decodable, Encodable)` to the enclosing struct/enum. It is more efficient to encode hashes directly than try to apply some varint encoding. This PR adds two new types `Hash64` and `Hash128` which are produced by `StableHasher` and replace every use of storing a `u64` or `u128` that represents a hash.
Distribution of the byte lengths of leb128 encodings, from `x build --stage 2` with `incremental = true`
Before:
```
( 1) 373418203 (53.7%, 53.7%): 1
( 2) 196240113 (28.2%, 81.9%): 3
( 3) 108157958 (15.6%, 97.5%): 2
( 4) 17213120 ( 2.5%, 99.9%): 4
( 5) 223614 ( 0.0%,100.0%): 9
( 6) 216262 ( 0.0%,100.0%): 10
( 7) 15447 ( 0.0%,100.0%): 5
( 8) 3633 ( 0.0%,100.0%): 19
( 9) 3030 ( 0.0%,100.0%): 8
( 10) 1167 ( 0.0%,100.0%): 18
( 11) 1032 ( 0.0%,100.0%): 7
( 12) 1003 ( 0.0%,100.0%): 6
( 13) 10 ( 0.0%,100.0%): 16
( 14) 10 ( 0.0%,100.0%): 17
( 15) 5 ( 0.0%,100.0%): 12
( 16) 4 ( 0.0%,100.0%): 14
```
After:
```
( 1) 372939136 (53.7%, 53.7%): 1
( 2) 196240140 (28.3%, 82.0%): 3
( 3) 108014969 (15.6%, 97.5%): 2
( 4) 17192375 ( 2.5%,100.0%): 4
( 5) 435 ( 0.0%,100.0%): 5
( 6) 83 ( 0.0%,100.0%): 18
( 7) 79 ( 0.0%,100.0%): 10
( 8) 50 ( 0.0%,100.0%): 9
( 9) 6 ( 0.0%,100.0%): 19
```
The remaining 9 or 10 and 18 or 19 are `u64` and `u128` respectively that have the high bits set. As far as I can tell these are coming primarily from `SwitchTargets`.
Fluent, with all the icu4x it brings in, takes quite some time to
compile. `fluent_messages!` is only needed in further downstream rustc
crates, but is blocking more upstream crates like `rustc_index`. By
splitting it out, we allow `rustc_macros` to be compiled earlier, which
speeds up `x check compiler` by about 5 seconds (and even more after the
needless dependency on `serde_json` is removed from
`rustc_data_structures`).
Various minor Idx-related tweaks
Nothing particularly exciting here, but a couple of things I noticed as I was looking for more index conversions to simplify.
cc https://github.com/rust-lang/compiler-team/issues/606
r? `@WaffleLapkin`
This allows us to get rid of the `rustc_const_eval->rustc_borrowck`
dependency edge which was delaying the compilation of borrowck.
The added utils in `rustc_middle` are small and should not affect
compile times there.
Rollup of 8 pull requests
Successful merges:
- #110153 (Fix typos in compiler)
- #110165 (rustdoc: use CSS `overscroll-behavior` instead of JavaScript)
- #110175 (Symbol cleanups)
- #110203 (Remove `..` from return type notation)
- #110205 (rustdoc: make settings radio and checks thicker, less contrast)
- #110222 (Improve the error message when forwarding a matched fragment to another macro)
- #110237 (Split out a separate feature gate for impl trait in associated types)
- #110241 (tidy: Issue an error when UI test limits are too high)
Failed merges:
- #110218 (Remove `ToRegionVid`)
r? `@ghost`
`@rustbot` modify labels: rollup
Refactor unwind in MIR
This makes unwinding from current `Option<BasicBlock>` into
```rust
enum UnwindAction {
Continue,
Cleanup(BasicBlock),
Unreachable,
Terminate,
}
```
cc `@JakobDegen` `@RalfJung` `@Amanieu`
Unify terminology used in unwind action and terminator, and reflect
the fact that a nounwind panic is triggered instead of an immediate
abort is triggered for this terminator.
Don't ICE when encountering `dyn*` in statics or consts
Since we have properly implemented `dyn*` support in CTFE (#107728), let's not ICE here anymore.
Fixes#105777
r? `@eholk`
Move a const-prop-lint specific hack from mir interpret to const-prop-lint and make it fallible
fixes#109743
This hack didn't need to live in the mir interpreter. For const-prop-lint it is entirely correct to avoid doing any const prop if normalization fails at this stage. Most likely we couldn't const propagate anything anyway, and if revealing was needed (so opaque types were involved), we wouldn't want to be too smart and leak the hidden type anyway.
Insert alignment checks for pointer dereferences when debug assertions are enabled
Closes https://github.com/rust-lang/rust/issues/54915
- [x] Jake tells me this sounds like a place to use `MirPatch`, but I can't figure out how to insert a new basic block with a new terminator in the middle of an existing basic block, using `MirPatch`. (if nobody else backs up this point I'm checking this as "not actually a good idea" because the code looks pretty clean to me after rearranging it a bit)
- [x] Using `CastKind::PointerExposeAddress` is definitely wrong, we don't want to expose. Calling a function to get the pointer address seems quite excessive. ~I'll see if I can add a new `CastKind`.~ `CastKind::Transmute` to the rescue!
- [x] Implement a more helpful panic message like slice bounds checking.
r? `@oli-obk`
And while doing the updates for that, also uses `FieldIdx` in `ProjectionKind::Field` and `TypeckResults::field_indices`.
There's more places that could use it (like `rustc_const_eval` and `LayoutS`), but I tried to keep this PR from exploding to *even more* places.
Part 2/? of https://github.com/rust-lang/compiler-team/issues/606
Lint against escape sequences in Fluent files
Fixes#109686 by checking for `\n`, `\"` and `\'` in Fluent files. It might be useful to have a way to opt out of this check, but all messages with violations currently do seem to be incorrect.
Support TLS access into dylibs on Windows
This allows access to `#[thread_local]` in upstream dylibs on Windows by introducing a MIR shim to return the address of the thread local. Accesses that go into an upstream dylib will call the MIR shim to get the address of it.
`convert_tls_rvalues` is introduced in `rustc_codegen_ssa` which rewrites MIR TLS accesses to dummy calls which are replaced with calls to the MIR shims when the dummy calls are lowered to backend calls.
A new `dll_tls_export` target option enables this behavior with a `false` value which is set for Windows platforms.
This fixes https://github.com/rust-lang/rust/issues/84933.
As I've been trying to replace a `Vec` with an `IndexVec`, having `last` exist on both but returning very different types makes the transition a bit awkward -- the errors are later, where you get things like "there's no `ty` method on `mir::Field`" rather than a more localized error like "hey, there's no `last` on `IndexVec`".
So I propose renaming `last` to `last_index` to help distinguish `Vec::last`, which returns an element, and `IndexVec::last_index`, which returns an index.
(Similarly, `Iterator::last` also returns an element, not an index.)
Add a builtin `FnPtr` trait that is implemented for all function pointers
r? `@ghost`
Rebased version of https://github.com/rust-lang/rust/pull/99531 (plus adjustments mentioned in the PR).
If perf is happy with this version, I would like to land it, even if the diagnostics fix in 9df8e1befb5031a5bf9d8dfe25170620642d3c59 only works for `FnPtr` specifically, and does not generally improve blanket impls.
Fixes#109543. When checking paths in HIR typeck, we don't want to check
for const predicates since all we want might just be a function pointer.
Therefore we move this to MIR constck and check that bounds are met
during MIR constck.
Since structs are always `VariantIdx(0)`, there's a bunch of files where the only reason they had `VariantIdx` or `vec::Idx` imported at all was to get the first variant.
So this uses a constant for that, and adds some doc-comments to `VariantIdx` while I'm there, since it doesn't have any today.
Updates `interpret`, `codegen_ssa`, and `codegen_cranelift` to consume the new cast instead of the intrinsic.
Includes `CastTransmute` for custom MIR building, to be able to test the extra UB.
Detect uninhabited types early in const eval
r? `@RalfJung`
implements https://github.com/rust-lang/rust/pull/108442#discussion_r1143003840
this is a breaking change, as some UB during const eval is now detected instead of silently being ignored. Users can see this and other UB that may cause future breakage with `-Zextra-const-ub-checks` or just by running miri on their code, which sets that flag by default.
a general type system cleanup
removes the helper functions `traits::fully_solve_X` as they add more complexity then they are worth. It's confusing which of these helpers should be used in which context.
changes the way we deal with overflow to always add depth in `evaluate_predicates_recursively`. It may make sense to actually fully transition to not have `recursion_depth` on obligations but that's probably a bit too much for this PR.
also removes some other small - and imo unnecessary - helpers.
r? types
Tweak implementation of overflow checking assertions
Extract and reuse logic controlling behaviour of overflow checking assertions instead of duplicating it three times.
r? `@cjgillot`
Wrap the whole LocalInfo in ClearCrossCrate.
MIR contains a lot of information about locals. The primary purpose of this information is the quality of borrowck diagnostics.
This PR aims to drop this information after MIR analyses are finished, ie. starting from post-cleanup runtime MIR.
Implement checked Shl/Shr at MIR building.
This does not require any special handling by codegen backends,
as the overflow behaviour is entirely determined by the rhs (shift amount).
This allows MIR ConstProp to remove the overflow check for constant shifts.
~There is an existing different behaviour between cg_llvm and cg_clif (cc `@bjorn3).`
I took cg_llvm's one as reference: overflow if `rhs < 0 || rhs > number_of_bits_in_lhs_ty`.~
EDIT: `cg_llvm` and `cg_clif` implement the overflow check differently. This PR uses `cg_llvm`'s implementation based on a `BitAnd` instead of `cg_clif`'s one based on an unsigned comparison.
Strengthen state tracking in const-prop
Some/many of the changes are replicated between both the const-prop lint and the const-prop optimization.
Behaviour changes:
- const-prop opt does not give a span to propagated values. This was useless as that span's primary purpose is to diagnose evaluation failure in codegen.
- we remove the `OnlyPropagateInto` mode. It was only used for function arguments, which are better modeled by a write before entry.
- the tracking of assignments and discriminants make clearer that we do nothing in `NoPropagation` mode or on indirect places.
This makes it easier to open the messages file while developing on features.
The commit was the result of automatted changes:
for p in compiler/rustc_*; do mv $p/locales/en-US.ftl $p/messages.ftl; rmdir $p/locales; done
for p in compiler/rustc_*; do sed -i "s#\.\./locales/en-US.ftl#../messages.ftl#" $p/src/lib.rs; done
Rollup of 9 pull requests
Successful merges:
- #108879 (Unconstrained terms should account for infer vars being equated)
- #108936 (Rustdoc: don't hide anonymous reexport)
- #108940 (Add myself to compiler reviewers list)
- #108945 (Make some report and emit errors take DefIds instead of BodyIds)
- #108946 (Document the resulting values produced when using `From<bool>` on floats)
- #108956 (Make ptr::from_ref and ptr::from_mut in #106116 const.)
- #108960 (Remove `body_def_id` from `Inherited`)
- #108963 (only call git on git checkouts during bootstrap)
- #108964 (Fix the docs for pointer method with_metadata_of)
Failed merges:
- #108950 (Directly construct Inherited in typeck.)
r? `@ghost`
`@rustbot` modify labels: rollup
Do not ICE when failing to normalize in ConstProp.
There is no reason to delay a bug there, as we bubble up the failure as TooGeneric.
Fixes https://github.com/rust-lang/rust/issues/97728
Check for free regions in MIR validation
This turns https://github.com/rust-lang/rust/issues/108720 into a MIR validation failure that will reproduce without debug-assertions enabled.
```
error: internal compiler error: broken MIR in Item(WithOptConstParam { did: DefId(0:296 ~ futures_util[3805]::future::future::remote_handle::{impl#3}::poll), const_param_did: None }) (after pass ScalarReplacementOfAggregates) at bb0[0]:
Free regions in optimized runtime-post-cleanup MIR
--> /home/ben/.cargo/registry/src/github.com-1ecc6299db9ec823/futures-util-0.3.26/src/future/future/remote_handle.rs:96:13
|
96 | let this = self.project();
| ^^^^
```
const_eval: `implies_by` in `rustc_const_unstable`
Fixes#107605.
Extend support for `implies_by` (from `#[stable]` and `#[unstable]`) to `#[rustc_const_stable]` and `#[rustc_const_unstable]`.
cc ``@steffahn``
rustc_middle: Remove trait `DefIdTree`
This trait was a way to generalize over both `TyCtxt` and `Resolver`, but now `Resolver` has access to `TyCtxt`, so this trait is no longer necessary.
Support allocations with non-Box<[u8]> bytes
This is prep work for allowing miri to support passing pointers to C code, which will require `Allocation`s to be correctly aligned. Currently, it just makes `Allocation` generic and plumbs the necessary changes through the right places.
The follow-up to this will be adding a type in the miri interpreter which correctly aligns the bytes, using that for the Miri engine, then allowing Miri to pass pointers into these allocations to C calls.
Based off of #100467, credit to ```@emarteca``` for the code
Avoid invoking typeck from borrowck
This PR attempts to reduce direct dependencies between typeck and MIR-related queries. The goal is to have all the information transit either through THIR or through dedicated queries that avoid depending on the whole `TypeckResults`.
In a first commit, we store the type information that MIR building requires into THIR. This avoids edges between mir_built and typeck.
In the second and third commit, we wrap informations around closures (upvars, kind origin and user-provided signature) to avoid borrowck depending on typeck information.
There should be a single remaining borrowck -> typeck edge in the good path, due to inline consts.
MIR-Validate StorageLive.
`StorageLive` statements on a local which already has storage is banned by miri.
This check is easy enough, and can detect bugs in MIR opts.
Unify validity checks into a single query
Previously, there were two queries to check whether a type allows the 0x01 or zeroed bitpattern.
I am planning on adding a further initness to check in #100423, truly uninit for MaybeUninit, which would make this three queries. This seems overkill for such a small feature, so this PR unifies them into one.
I am not entirely happy with the naming and key type and open for improvements.
r? oli-obk
(This is a large commit. The changes to
`compiler/rustc_middle/src/ty/context.rs` are the most important ones.)
The current naming scheme is a mess, with a mix of `_intern_`, `intern_`
and `mk_` prefixes, with little consistency. In particular, in many
cases it's easy to use an iterator interner when a (preferable) slice
interner is available.
The guiding principles of the new naming system:
- No `_intern_` prefixes.
- The `intern_` prefix is for internal operations.
- The `mk_` prefix is for external operations.
- For cases where there is a slice interner and an iterator interner,
the former is `mk_foo` and the latter is `mk_foo_from_iter`.
Also, `slice_interners!` and `direct_interners!` can now be `pub` or
non-`pub`, which helps enforce the internal/external operations
division.
It's not perfect, but I think it's a clear improvement.
The following lists show everything that was renamed.
slice_interners
- const_list
- mk_const_list -> mk_const_list_from_iter
- intern_const_list -> mk_const_list
- substs
- mk_substs -> mk_substs_from_iter
- intern_substs -> mk_substs
- check_substs -> check_and_mk_substs (this is a weird one)
- canonical_var_infos
- intern_canonical_var_infos -> mk_canonical_var_infos
- poly_existential_predicates
- mk_poly_existential_predicates -> mk_poly_existential_predicates_from_iter
- intern_poly_existential_predicates -> mk_poly_existential_predicates
- _intern_poly_existential_predicates -> intern_poly_existential_predicates
- predicates
- mk_predicates -> mk_predicates_from_iter
- intern_predicates -> mk_predicates
- _intern_predicates -> intern_predicates
- projs
- intern_projs -> mk_projs
- place_elems
- mk_place_elems -> mk_place_elems_from_iter
- intern_place_elems -> mk_place_elems
- bound_variable_kinds
- mk_bound_variable_kinds -> mk_bound_variable_kinds_from_iter
- intern_bound_variable_kinds -> mk_bound_variable_kinds
direct_interners
- region
- intern_region (unchanged)
- const
- mk_const_internal -> intern_const
- const_allocation
- intern_const_alloc -> mk_const_alloc
- layout
- intern_layout -> mk_layout
- adt_def
- intern_adt_def -> mk_adt_def_from_data (unusual case, hard to avoid)
- alloc_adt_def(!) -> mk_adt_def
- external_constraints
- intern_external_constraints -> mk_external_constraints
Other
- type_list
- mk_type_list -> mk_type_list_from_iter
- intern_type_list -> mk_type_list
- tup
- mk_tup -> mk_tup_from_iter
- intern_tup -> mk_tup
Previously, there were two queries to check whether a type allows the
0x01 or zeroed bitpattern.
I am planning on adding a further initness to check, truly uninit for
MaybeUninit, which would make this three queries. This seems overkill
for such a small feature, so this PR unifies them into one.
Remove type-traversal trait aliases
#107924 moved the type traversal (folding and visiting) traits into the type library, but created trait aliases in `rustc_middle` to minimise both the API churn for trait consumers and the arising boilerplate. As mentioned in that PR, an alternative approach of defining subtraits with blanket implementations of the respective supertraits was also considered at that time but was ruled out as not adding much value.
Unfortunately, it has since emerged that rust-analyzer has difficulty with these trait aliases at present, resulting in a degraded contributor experience (see the recent [r-a has become useless](https://rust-lang.zulipchat.com/#narrow/stream/182449-t-compiler.2Fhelp/topic/r-a.20has.20become.20useless) topic on the #t-compiler/help Zulip stream).
This PR removes the trait aliases, and accordingly the underlying type library traits are now used directly; they are parameterised by `TyCtxt<'tcx>` rather than just the `'tcx` lifetime, and imports have been updated to reflect the fact that the trait aliases' explicitly named traits are no longer automatically brought into scope. These changes also roll-back the (no-longer required) workarounds to #107747 that were made in b409329c62.
Since this PR is just a find+replace together with the changes necessary for compilation & tidy to pass, it's currently just one mega-commit. Let me know if you'd like it broken up.
r? `@oli-obk`
Instead of loading the Fluent resources for every crate in
`rustc_error_messages`, each crate generates typed identifiers for its
own diagnostics and creates a static which are pulled together in the
`rustc_driver` crate and provided to the diagnostic emitter.
Signed-off-by: David Wood <david.wood@huawei.com>
Miri: basic dyn* support
As usual I am very unsure about the dynamic dispatch stuff, but it passes even the `Pin<&mut dyn* Trait>` test so that is something.
TBH I think it was a mistake to make `dyn Trait` and `dyn* Trait` part of the same `TyKind` variant. Almost everywhere in Miri this lead to the wrong default behavior, resulting in strange ICEs instead of nice "unimplemented" messages. The two types describe pretty different runtime data layout after all.
Strangely I did not need to do the equivalent of [this diff](https://github.com/rust-lang/rust/pull/106532#discussion_r1087095963) in Miri. Maybe that is because the unsizing logic matches on `ty::Dynamic(.., ty::Dyn)` already? In `unsized_info` I don't think the `target_dyn_kind` can be `DynStar`, since then it wouldn't be unsized!
r? `@oli-obk` Cc `@eholk` (dyn-star) https://github.com/rust-lang/rust/issues/102425
There are several `mk_foo`/`intern_foo` pairs, where the former takes an
iterator and the latter takes a slice. (This naming convention is bad,
but that's a fix for another PR.)
This commit changes several `mk_foo` occurrences into `intern_foo`,
avoiding the need for some `.iter()`/`.into_iter()` calls. Affected
cases:
- mk_type_list
- mk_tup
- mk_substs
- mk_const_list
Don't ICE in `might_permit_raw_init` if reference is polymorphic
Emitting optimized MIR for a polymorphic function may require computing layout of a type that isn't (yet) known. This happens in the instcombine pass, for example. Let's fail gracefully in that condition.
cc `@saethlin`
fixes#107999
Use `target` instead of `machine` for mir interpreter integer handling.
The naming of `machine` only makes sense from a mir interpreter internals perspective, but outside users talk about the `target` platform. As per https://github.com/rust-lang/rust/pull/108029#issuecomment-1429791015
r? `@RalfJung`
Avoid accessing HIR when it can be avoided
Experiment to see if it helps some incremental cases.
Will be rebased once https://github.com/rust-lang/rust/pull/107942 gets merged.
r? `@ghost`
interpret: rename Pointer::from_addr → from_addr_invalid
This function corresponds to `ptr::invalid` in the standard library; the previous name was not clear enough IMO.
Extend support for `implies_by` (from `#[stable]` and `#[unstable]`)
to `#[rustc_const_stable]` and `#[rustc_const_unstable]`.
Signed-off-by: David Wood <david.wood@huawei.com>
Rename `PointerSized` to `PointerLike`
The old name was unnecessarily vague. This PR renames a nightly language feature that I added, so I don't think it needs any additional approval, though anyone can feel free to speak up if you dislike the rename.
It's still unsatisfying that we don't the user which of {size, alignment} is wrong, but this trait really is just a stepping stone for a more generalized mechanism to create `dyn*`, just meant for nightly testing, so I don't think it really deserves additional diagnostic machinery for now.
Fixes#107696, cc ``@RalfJung``
r? ``@eholk``
Modify existing bounds if they exist
Fixes#107335.
This implementation is kinda gross but I don't really see a better way to do it.
This primarily does two things: Modifies `suggest_constraining_type_param` to accept a new parameter that indicates a span to be replaced instead of added, if presented, and limit the additive suggestions to either suggest a new bound on an existing bound (see newly added unit test) or add the generics argument if a generics argument wasn't found.
The former change is required to retain the capability to add an entirely new bounds if it was entirely omitted.
r? ``@compiler-errors``
interpret: move discriminant reading and writing to separate file
This is quite different from the otherwise fairly general read and write functions in place.rs and operand.rs, and also it's nice to have these two functions close together as they are basically inverses of each other.
Bump bootstrap compiler to 1.68
This also changes our stage0.json to include the rustc component for the rustfmt pinned nightly toolchain, which is currently necessary due to rustfmt dynamically linking to that toolchain's librustc_driver and libstd.
r? `@pietroalbini`
Use stable metric for const eval limit instead of current terminator-based logic
This patch adds a `MirPass` that inserts a new MIR instruction `ConstEvalCounter` to any loops and function calls in the CFG. This instruction is used during Const Eval to count against the `const_eval_limit`, and emit the `StepLimitReached` error, replacing the current logic which uses Terminators only.
The new method of counting loops and function calls should be more stable across compiler versions (i.e., not cause crates that compiled successfully before, to no longer compile when changes to the MIR generation/optimization are made).
Also see: #103877
remove unnecessary check for opaque types
this isn't needed and may hide some errors.
after analysis there are no opaque types so it's a noop anyways
before analysis there are opaque types but due to `Reveal::UserFacing` we don't reveal them. `is_subtype` simply discards the opaque type constraints as these will get checked again during mir borrowck.
r? types
want to land this after the beta-cutoff as mir validator changes are apparently pretty scary
Rollup of 11 pull requests
Successful merges:
- #106407 (Improve proc macro attribute diagnostics)
- #106960 (Teach parser to understand fake anonymous enum syntax)
- #107085 (Custom MIR: Support binary and unary operations)
- #107086 (Print PID holding bootstrap build lock on Linux)
- #107175 (Fix escaping inference var ICE in `point_at_expr_source_of_inferred_type`)
- #107204 (suggest qualifying bare associated constants)
- #107248 (abi: add AddressSpace field to Primitive::Pointer )
- #107272 (Implement ObjectSafe and WF in the new solver)
- #107285 (Implement `Generator` and `Future` in the new solver)
- #107286 (ICE in new solver if we see an inference variable)
- #107313 (Add Style Team Triagebot config)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
abi: add AddressSpace field to Primitive::Pointer
...and remove it from `PointeeInfo`, which isn't meant for this.
There are still various places (marked with FIXMEs) that assume all pointers
have the same size and alignment. Fixing this requires parsing non-default
address spaces in the data layout string (and various other changes),
which will be done in a followup.
(That is, if it's actually worth it to support multiple different pointer sizes.
There is a lot of code that would be affected by that.)
Fixes#106367
r? ``@oli-obk``
cc ``@Patryk27``
InstCombine away intrinsic validity assertions
This optimization (currently) fires 246 times on the standard library. It seems to fire hardly at all on the big crates in the benchmark suite. Interesting.
- Remove logic that limits const eval based on terminators, and use the
stable metric instead (back edges + fn calls)
- Add unstable flag `tiny-const-eval-limit` to add UI tests that do not
have to go up to the regular 2M step limit
This patch adds a `MirPass` that tracks the number of back-edges and
function calls in the CFG, adds a new MIR instruction to increment a
counter every time they are encountered during Const Eval, and emit a
warning if a configured limit is breached.
use LocalDefId instead of HirId in trait resolution to simplify
the obligation clause resolution
Signed-off-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
...and remove it from `PointeeInfo`, which isn't meant for this.
There are still various places (marked with FIXMEs) that assume all pointers
have the same size and alignment. Fixing this requires parsing non-default
address spaces in the data layout string, which will be done in a followup.
Switching them to `Break(())` and `Continue(())` instead.
libs-api would like to remove these constants, so stop using them in compiler to make the removal PR later smaller.
Polymorphization cleanup
Split out of #106233
Use a newtype instead of a bitset directly. This makes the code way easier to read and easier to adapt for future changes.
Rollup of 6 pull requests
Successful merges:
- #105567 (KCFI test: Also support LLVM 16 output)
- #105847 (Ensure param-env is const before calling `eval_to_valtree`)
- #105983 (Add a missing early return in drop tracking `handle_uninhabited_return`)
- #106027 (rustdoc: simplify CSS and DOM for more-scraped-examples)
- #106035 (Migrate search tab title color to CSS variable)
- #106037 (Add regression test for #94293)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Ensure param-env is const before calling `eval_to_valtree`
Other queries call `ParamEnv::with_const` *inside* of the query itself (e.g. `const_eval_global_id_for_typeck`), so this could alternatively be moved into the provider of `eval_to_valtree` instead. I don't have a particularly strong opinion, though *theoretically* caching is better if we make the query keys more constrained.
I'm not exactly sure how this is an effect of the `-Zmir-opt-level=3` flag. Maybe something about the inliner causes us to inline an unevaluated const into a body where it can be evaluated, but where it has not yet been normalized.
This seems likely, since we're inlining `from_fn_1::<{ N / 2 }, _>` in `from_fn_2`, which means that we will need to evaluate that constant during the const prop pass after inlining.
Fixes#104396
Retag as FnEntry on `drop_in_place`
This commit changes the mir drop shim to always retag its argument as if it were a `&mut`.
cc rust-lang/unsafe-code-guidelines#373
Rollup of 8 pull requests
Successful merges:
- #105584 (add assert messages if chunks/windows are length 0)
- #105602 (interpret: add read_machine_[ui]size convenience methods)
- #105824 (str.lines() docstring: clarify that line endings are not returned)
- #105980 (Refer to "Waker" rather than "RawWaker" in `drop` comment)
- #105986 (Fix typo in reading_half_a_pointer.rs)
- #105995 (Add regression test for #96530)
- #106008 (Sort lint_groups in no_lint_suggestion)
- #106014 (Add comment explaining what the scrape-examples-toggle.goml GUI test is about)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Rename `assert_uninit_valid` intrinsic
It's not about "uninit" anymore but about "filling with 0x01 bytes" so the name should at least try to reflect that.
This is actually not fully correct though, as it does still panic for all uninit with `-Zstrict-init-checks`. I'm not sure what the best way is to deal with that not causing confusion. I guess we could just remove the flag? I don't think having it makes a lot of sense anymore with the direction that we have chose to go. It could be relevant again if #100423 lands so removing it may be a bit over eager.
r? `@RalfJung`
Combine `ty::Projection` and `ty::Opaque` into `ty::Alias`
Implements https://github.com/rust-lang/types-team/issues/79.
This PR consolidates `ty::Projection` and `ty::Opaque` into a single `ty::Alias`, with an `AliasKind` and `AliasTy` type (renamed from `ty::ProjectionTy`, which is the inner data of `ty::Projection`) defined as so:
```
enum AliasKind {
Projection,
Opaque,
}
struct AliasTy<'tcx> {
def_id: DefId,
substs: SubstsRef<'tcx>,
}
```
Since we don't have access to `TyCtxt` in type flags computation, and because repeatedly calling `DefKind` on the def-id is expensive, these two types are distinguished with `ty::AliasKind`, conveniently glob-imported into `ty::{Projection, Opaque}`. For example:
```diff
match ty.kind() {
- ty::Opaque(..) =>
+ ty::Alias(ty::Opaque, ..) => {}
_ => {}
}
```
This PR also consolidates match arms that treated `ty::Opaque` and `ty::Projection` identically.
r? `@ghost`
Don't require owned data in `MaybeStorageLive`
Small improvement that avoids a clone. I don't expect this to have any noticeable perf effects, but better to have it than not to.
r? ``@tmiasko``
compiler: remove unnecessary imports and qualified paths
Some of these imports were necessary before Edition 2021, others were already in the prelude.
I hope it's fine that this PR is so spread-out across files :/
use the correct `Reveal` during validation
supersedes #105454. Deals with https://github.com/rust-lang/rust/issues/105009#issuecomment-1342395333, not closing #105009 as the ICE may leak into beta
The issue was the following:
- we optimize the mir, using `Reveal::All`
- some optimization relies on the hidden type of an opaque type
- we then validate using `Reveal::UserFacing` again which is not able to observe the hidden type
r? `@jackh726`
interpret: clobber return place when calling function
Makes sure the callee cannot observe the previous contents of the return place, and the caller cannot read any of the old return place contents even if the function unwinds.
I don't think we can test for this though, that would require some strange hand-written MIR.
r? `````@oli-obk`````
Some initial normalization method changes
1. Rename `AtExt::normalize` to `QueryNormalizeExt::query_normalize` (using the `QueryNormalizer`)
2. Introduce `NormalizeExt::normalize` to replace `partially_normalize_associated_types_in` (using the `AssocTypeNormalizer`)
3. Rename `FnCtxt::normalize_associated_types_in` to `FnCtxt::normalize`
4. Remove some unused other normalization fns in `Inherited` and `FnCtxt`
Also includes one drive-by where we're no longer creating a `FnCtxt` inside of `check_fn`, but passing it in. This means we don't need such weird `FnCtxt` construction logic.
Stacked on top of #104835 for convenience.
r? types
Prefer doc comments over `//`-comments in compiler
Doc comments are generally nicer: they show up in the documentation, they are shown in IDEs when you hover other mentions of items, etc. Thus it makes sense to use them instead of `//`-comments.
Pretty-print generators with their `generator_kind`
After removing `GenFuture`, I special-cased async generators to pretty-print as `impl Future<Output = X>` mainly to avoid too much diagnostics changes originally.
This now reverses that change so that async fn/blocks are pretty-printed as `[$async-type@$source-position]` in various diagnostics, and updates the tests that this touches.
After removing `GenFuture`, I special-cased async generators to pretty-print as `impl Future<Output = X>` mainly to avoid too much diagnostics changes originally.
This now reverses that change so that async fn/blocks are pretty-printed as `[$movability `async` $something@$source-position]` in various diagnostics, and updates the tests that this touches.
Add `ConstKind::Expr`
Starting to implement `ty::ConstKind::Abstract`, most of the match cases are stubbed out, some I was unsure what to add, others I didn't want to add until a more complete implementation was ready.
r? `@lcnr`
Initial pass at expr/abstract const/s
Address comments
Switch to using a list instead of &[ty::Const], rm `AbstractConst`
Remove try_unify_abstract_consts
Update comments
Add edits
Recurse more
More edits
Prevent equating associated consts
Move failing test to ui
Changes this test from incremental to ui, and mark it as failing and a known bug.
Does not cause the compiler to ICE, so should be ok.
Previously, async constructs would be lowered to "normal" generators,
with an additional `from_generator` / `GenFuture` shim in between to
convert from `Generator` to `Future`.
The compiler will now special-case these generators internally so that
async constructs will *directly* implement `Future` without the need
to go through the `from_generator` / `GenFuture` shim.
The primary motivation for this change was hiding this implementation
detail in stack traces and debuginfo, but it can in theory also help
the optimizer as there is less abstractions to see through.
Add `PolyExistentialPredicate` type alias
Wrapping `ExistentialPredicate`s in a binder is very common, and this alias already exists for the `PolyExistential{TraitRef,Projection}` types.
Improve spans for RPITIT object-safety errors
No reason why we can't point at the `impl Trait` that causes the object-safety violation.
Also [drive-by: Add is_async fn to hir::IsAsync](c4165f3a96), which touches clippy too.
nll: correctly deal with bivariance
fixes#104409
when in a bivariant context, relating stuff should always trivially succeed. Also changes the mir validator to correctly deal with higher ranked regions.
r? types cc ``@RalfJung``
Convert predicates into Predicate in the Obligation constructor
instead of having almost all callers do that.
This reduces a bit of boilerplate, and also paves the way for my work towards https://github.com/rust-lang/compiler-team/issues/531 (as it makes it easier to accept both goals and clauses where right now it only accepts predicates).
interpret: support for per-byte provenance
Also factors the provenance map into its own module.
The third commit does the same for the init mask. I can move it in a separate PR if you prefer.
Fixes https://github.com/rust-lang/miri/issues/2181
r? `@oli-obk`
interpret: move type_name implementation to an interpreter-independent helper file
This should avoid pinging rust-lang/miri each time that file changes, which is really not necessary.
r? `@oli-obk`
Accept `TyCtxt` instead of `TyCtxtAt` in `Ty::is_*` functions
Functions in answer:
- `Ty::is_freeze`
- `Ty::is_sized`
- `Ty::is_unpin`
- `Ty::is_copy_modulo_regions`
This allows to remove a lot of useless `.at(DUMMY_SP)`, making the code a bit nicer :3
r? `@compiler-errors`
Add eval hack in `super_relate_consts` back
Partially reverts 01adb7e98d.
This extra eval call *still* needs to happen, for example, in `normalize_param_env_or_error` when a param-env predicate has an unnormalized constant, since the param-env candidates never get normalized during candidate assembly (everywhere else we can assume that they are normalized fully).
r? `@lcnr,` though I feel like I've assigned quite a few PRs to you in the last few days, so feel free to reassign to someone else familiar with this code if you're busy!
cc #103243 (fixes the issue, but don't want to auto-close that until a backport is performed).
Split phase change from `MirPass`
The main goal here is to simplify the pass manager logic. `MirPass` no longer contains the `phase_change` method, and `run_passes` instead accepts an `Option<PhaseChange>`. The hope is that this addresses the comments (and maybe perf regression) from #99102 .
r? `@oli-obk` cc `@RalfJung`
interpret: remove an incorrect assertion
This fixes an ICE in Miri, [reported](https://rust-lang.zulipchat.com/#narrow/stream/269128-miri/topic/SwitchInt.20with.20no.20targets.3F) by `@saethlin.` The faulty assertion was introduced by 432535da2b, when a previously correct assertion checking that the `otherwise` target exists got replaced by this assertion checking that at least one more target beyond `otherwise` exists.
Sadly we don't have a small reproducer so I don't think we can easily add a testcase.
More dupe word typos
I only picked those changes (from the regex search) that I am pretty certain doesn't change meaning and is just a typo fix. Do correct me if any fix is undesirable and I can revert those. Thanks.
Unify `tcx.constness` query and param env constness checks
The checks that we do in the `constness` query seem inconsistent with the checks that we do to determine if an item's param-env is const, so I merged them into the `constness` query and call that from the `param_env` query.
I'm not sure if this totally makes sense -- is there a case where `tcx.param_env()` would return a const param-env for an item whose `tcx.constness()` is `Constness::NotConst`? Because if not, it seems a bit dangerous that these two differ.
Luckily, not many places actually use `tcx.constness()`, and the checks in `tcx.param_env()` seem stricter than the checks in `tcx.constness()` (at least for the types of items we type-check).
Also, due to the way that `tcx.param_env()` is implemented, it _never_ used to return a const param-env for a item coming from a different crate, which also seems dangerous (though also probably not weaponizable currently, because we seldom actually compute the param-env for a non-local item).
Remove `mir::CastKind::Misc`
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````
Don't ICE when trying to copy unsized value in const prop
When we have a trivially false where-clause predicate like `Self: Sized` where `Self = dyn Trait`, we sometimes don't throw an error during typeck for an illegal operation such as copying an unsized type.
This, unfortunately, cannot be made into an error (at least not without some migration -- see #95611 for example), but we should at least not ICE, since this function will never actually be reachable from main, for example.
r? `@RalfJung` since I think you added these assertions? but feel free to reassign.
Fixes#102553
Introduce mir::Unevaluated
Previously the distinction between unevaluated constants in the type-system and in mir was not explicit and a little confusing. Probably better to introduce its own type for that.
r? `@lcnr`
interpret: expose generate_stacktrace without full InterpCx
In Miri we sometimes want to emit diagnostics without having a full `&InterpCx` available. To avoid duplicating code, this adds a way to get a stacktrace from an arbitrary slice of interpreter frames, that Miri can use with access to just a thread manager.
On later stages, the feature is already stable.
Result of running:
rg -l "feature.let_else" compiler/ src/librustdoc/ library/ | xargs sed -s -i "s#\\[feature.let_else#\\[cfg_attr\\(bootstrap, feature\\(let_else\\)#"
The `<*const T>::guaranteed_*` methods now return an option for the unknown case
cc https://github.com/rust-lang/rust/issues/53020#issuecomment-1236932443
I chose `0` for "not equal" and `1` for "equal" and left `2` for the unknown case so backends can just forward to raw pointer equality and it works ✨
r? `@fee1-dead` or `@lcnr`
cc `@rust-lang/wg-const-eval`
Normalize before erasing late-bound regions in `equal_up_to_regions`
Normalize erasing regions **first**, before passing the type through a `BottomUpFolder` which erases late-bound regions too.
The root cause of this issue is due to 96d4137dee, which removes a `normalize_erasing_regions` that happens before this call to `equal_up_to_regions`. While reverting that commit might be a fix, I think it was suspicious to be erasing late-bound regions first _then_ normalizing types in the first place in `equal_up_to_regions`.
-----
I am tempted to ask the reviewer to review and `r+` this without a UI test, since the existing issues that I think this fixes are all incredibly difficult to minimize (anything hyper/warp related, given the nature of those libraries 😓) or impossible to reproduce locally (the miri test), namely:
* This recently reported issue with tokio + warp: #101430
* This issue from `@RalfJung` about Miri being broken: #101344
* This additional issue reported in a comment by `@tmandry` (issue with fuchsia + hyper): https://github.com/rust-lang/rust/issues/101344#issuecomment-1235974564
I have locally verified that the repro in #101430 is fixed with this PR, but after a couple of hours of attempting to minimize this error and either failing to actually repro the ICE, or being overwhelmed with the number of traits and functions I need to inline into a UI test, I have basically given up. Thoughts are appreciated on how best to handle this.
r? `@oli-obk` who is at the intersection of MIR and types-related stuff who may be able to give advice 😅
Add a Machine hook for inline assembly
I'm sketching out some support in Miri to "execute" inline assembly. I want this because there are codebases which have very simple inline assembly like hand-written syscall wrappers, and it would be nice to test such code without modification.
r? ``@oli-obk``
Try normalizing types without RevealAll in ParamEnv in MIR validation
Before, the MIR validator used RevealAll in its ParamEnv for type
checking. This could cause false negatives in some cases due to
RevealAll ParamEnvs not always use all predicates as expected here.
Since some MIR passes like inlining use RevealAll as well, keep using
it in the MIR validator too, but when it fails usign RevealAll, also
try the check without it, to stop false negatives.
Fixes#99866
cc ````````@compiler-errors```````` who nicely helped me on zulip
Fix a bunch of typo
This PR will fix some typos detected by [typos].
I only picked the ones I was sure were spelling errors to fix, mostly in
the comments.
[typos]: https://github.com/crate-ci/typos
This PR will fix some typos detected by [typos].
I only picked the ones I was sure were spelling errors to fix, mostly in
the comments.
[typos]: https://github.com/crate-ci/typos
Rework definition of MIR phases to more closely reflect semantic concerns
Implements most of rust-lang/compiler-team#522 .
I tried my best to restrict this PR to the "core" parts of the MCP. In other words, this includes just enough changes to make the new definition of `MirPhase` make sense. That means there are a couple of FIXMEs lying around. Depending on what reviewers prefer, I can either fix them in this PR or send follow up PRs. There are also a couple other refactorings of the `rustc_mir_transform/src/lib.rs` file that I want to do in follow ups that I didn't leave explicit FIXMEs for.
Rollup of 9 pull requests
Successful merges:
- #95376 (Add `vec::Drain{,Filter}::keep_rest`)
- #100092 (Fall back when relating two opaques by substs in MIR typeck)
- #101019 (Suggest returning closure as `impl Fn`)
- #101022 (Erase late bound regions before comparing types in `suggest_dereferences`)
- #101101 (interpret: make read-pointer-as-bytes a CTFE-only error with extra information)
- #101123 (Remove `register_attr` feature)
- #101175 (Don't --bless in pre-push hook)
- #101176 (rustdoc: remove unused CSS selectors for `.table-display`)
- #101180 (Add another MaybeUninit array test with const)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
interpret: make read-pointer-as-bytes a CTFE-only error with extra information
Next step in the reaction to https://github.com/rust-lang/rust/issues/99923. Also teaches Miri to implicitly strip provenance in more situations when transmuting pointers to integers, which fixes https://github.com/rust-lang/miri/issues/2456.
Pointer-to-int transmutation during CTFE now produces a message like this:
```
= help: this code performed an operation that depends on the underlying bytes representing a pointer
= help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
```
r? ``@oli-obk``
Revert let_chains stabilization
This is the revert against master, the beta revert was already done in #100538.
Bumps the stage0 compiler which already has it reverted.
Rollup of 7 pull requests
Successful merges:
- #100898 (Do not report too many expr field candidates)
- #101056 (Add the syntax of references to their documentation summary.)
- #101106 (Rustdoc-Json: Retain Stripped Modules when they are imported, not when they have items)
- #101131 (CTFE: exposing pointers and calling extern fn is just impossible)
- #101141 (Simplify `get_trait_ref` fn used for `virtual_function_elimination`)
- #101146 (Various changes to logging of borrowck-related code)
- #101156 (Remove `Sync` requirement from lint pass objects)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
CTFE: exposing pointers and calling extern fn is just impossible
The remaining "needs RFC" errors are just needlessly confusing, I think -- time to get rid of that error variant. They are anyway only reachable with miri-unleashed (if at all).
r? `@oli-obk`
Before, the MIR validator used RevealAll in its ParamEnv for type
checking. This could cause false negatives in some cases due to
RevealAll ParamEnvs not always use all predicates as expected here.
Since some MIR passes like inlining use RevealAll as well, keep using
it in the MIR validator too, but when it fails usign RevealAll, also
try the check without it, to stop false negatives.
remove an ineffective check in const_prop
Based on https://github.com/rust-lang/rust/pull/100043, only the last two commits are new.
ConstProp has a special check when reading from a local that prevents reading uninit locals. However, if that local flows into `force_allocation`, then no check fires and evaluation proceeds. So this check is not really effective at preventing accesses to uninit locals.
With https://github.com/rust-lang/rust/pull/100043, `read_immediate` and friends always fail when reading uninit locals, so I don't see why ConstProp would need a separate check. Thus I propose we remove it. This is needed to be able to do https://github.com/rust-lang/rust/pull/100085.
extra sanity check against consts pointing to mutable memory
This should be both unreachable and redundant (since we already ensure that validation only reads from read-only memory, when validating consts), but I feel like we cannot be paranoid enough here, and also if this ever fails it'll be a nicer error than the "cannot read from mutable memory" error.
Replace `Body::basic_blocks()` with field access
Since the refactoring in #98930, it is possible to borrow the basic blocks
independently from other parts of MIR by accessing the `basic_blocks` field
directly.
Replace unnecessary `Body::basic_blocks()` method with a direct field access,
which has an additional benefit of borrowing the basic blocks only.
no alignment check during interning
This should fix https://github.com/rust-lang/rust/issues/101034
r? `@oli-obk`
Unfortunately we don't have a self-contained testcase for this problem. I am not sure how it can be triggered...
Diagnostics migr const eval
This PR should eventually contain all diagnostic migrations for the `rustc_const_eval` crate.
r? `@davidtwco`
`@rustbot` label +A-translation
Because `PassMode::Cast` is by far the largest variant, but is
relatively rare.
This requires making `PassMode` not impl `Copy`, and `Clone` is no
longer necessary. This causes lots of sigil adjusting, but nothing very
notable.
Check projection types before inlining MIR
Fixes https://github.com/rust-lang/rust/issues/100550
I'm very unhappy with this solution, having to duplicate MIR validation code, but at least it removes the ICE.
r? `@compiler-errors`
suggest `once_cell::Lazy` for non-const statics
Addresses https://github.com/rust-lang/rust/issues/100410
Some questions:
- removing the `if` seems to include too many cases (e.g. calls to non-const functions inside a `const fn`), but this code excludes the following case:
```rust
const FOO: Foo = non_const_fn();
```
Should we suggest `once_cell` in this case as well?
- The original issue mentions suggesting `AtomicI32` instead of `Mutex<i32>`, should this PR address that as well?
Rename Machine memory hooks to suggest when they run
Some of the other memory hooks start with `before_` or `after_` to indicate that they run before or after a certain operation. These don't, so I was a bit confused as to when they are supposed to run.
`memory_read` can be read two ways in English, "memory was read" or "this is a memory read" so without the prefix this was especially ambiguous.
Erase regions better in `promote_candidate`
Use `tcx.erase_regions` instead of manually walking through the substs.... this also makes the code slightly simpler 🙈Fixes#100360Fixes#89851
Use `TraitEngine` in more places that don't specifically need `FulfillmentContext::new_in_snapshot`
Not sure if this change is worthwhile, but couldn't hurt re: chalkification
r? types
Improve size assertions.
- For any file with four or more size assertions, move them into a
separate module (as is already done for `hir.rs`).
- Add some more for AST nodes and THIR nodes.
- Put the `hir.rs` ones in alphabetical order.
r? `@lqd`
- For any file with four or more size assertions, move them into a
separate module (as is already done for `hir.rs`).
- Add some more for AST nodes and THIR nodes.
- Put the `hir.rs` ones in alphabetical order.
Deeply deny fn and raw ptrs in const generics
I think this is right -- just because we wrap a fn ptr in a wrapper type does not mean we should allow it in a const parameter.
We now reject both of these in the same way:
```
#![feature(adt_const_params)]
#[derive(Eq, PartialEq)]
struct Wrapper();
fn foo<const W: Wrapper>() {}
fn foo2<const F: fn()>() {}
```
This does regress one test (`src/test/ui/consts/refs_check_const_eq-issue-88384.stderr`), but I'm not sure it should've passed in the first place.
cc: ``@b-naber`` who introduced that test^
fixes#99641
interpret, ptr_offset_from: refactor and test too-far-apart check
We didn't have any tests for the "too far apart" message, and indeed that check mostly relied on the in-bounds check and was otherwise probably not entirely correct... so I rewrote that check, and it is before the in-bounds check so we can test it separately.
interpret: rename Tag/PointerTag to Prov/Provenance
We were pretty inconsistent with calling this the "tag" vs the "provenance" of the pointer; I think we should consistently call it "provenance".
r? `@oli-obk`
Let's avoid using two different terms for the same thing -- let's just call it "provenance" everywhere.
In Miri, provenance consists of an AllocId and an SbTag (Stacked Borrows tag), which made this even more confusing.
interpret: make some large types not Copy
Also remove some unused trait impls (mostly HashStable).
This didn't find any unnecessary copies that I managed to avoid, but it might still be better to require explicit clone for these types? Not sure.
r? `@oli-obk`
Use constant eval to do strict mem::uninit/zeroed validity checks
I'm not sure about the code organisation here, I just dumped the check in rustc_const_eval at the root. Not hard to move it elsewhere, in any case.
Also, this means cranelift codegen intrinsics lose the strict checks, since they don't seem to depend on rustc_const_eval, and I didn't see a point in keeping around two copies.
I also left comments in the is_zero_valid methods about "uhhh help how do i do this", those apply to both methods equally.
Also rustc_codegen_ssa now depends on rustc_const_eval... is this okay?
Pinging `@RalfJung` since you were the one who mentioned this to me, so I'm assuming you're interested.
Haven't had a chance to run full tests on this since it's really warm, and it's 1AM, I'll check out any failures/comments in the morning :)
interpret/visitor: support visiting with a PlaceTy
Finally we can visit a `PlaceTy` in a way that will only do `force_allocation` when needed ti visit a field. :)
r? `@oli-obk`
interpret: get rid of MemPlaceMeta::Poison
This is achieved by refactoring the projection code (`{mplace,place,operand}_{downcast,field,index,...}`) so that we no longer need to call `assert_mem_place` in the operand handling.
Pull Derefer before ElaborateDrops
_Follow up work to #97025#96549#96116#95887 #95649_
This moves `Derefer` before `ElaborateDrops` and creates a new `Rvalue` called `VirtualRef` that allows us to bypass many constraints for `DerefTemp`.
r? `@oli-obk`
interpret: refactor projection handling code
Moves our projection handling code into a common file, and avoids the use of a
general mplace-based fallback function by have more specialized implementations.
mplace_index (and the other slice-related functions) could be more efficient by
copy-pasting the body of operand_index. Or we could do some trait magic to share
the code between them. But for now this is probably fine.
This is the common part of https://github.com/rust-lang/rust/pull/99013 and https://github.com/rust-lang/rust/pull/99097. I am seeing some strange perf results so this probably should be its own change so we know which diff caused which perf changes...
r? `@oli-obk`
Moves our projection handling code into a common file, and avoids the use of a
general mplace-based fallback function by have more specialized implementations.
mplace_index (and the other slice-related functions) could be more efficient by
copy-pasting the body of operand_index. Or we could do some trait magic to share
the code between them. But for now this is probably fine.
Implement `SourceMap::is_span_accessible`
This patch adds `SourceMap::is_span_accessible` and replaces `span_to_snippet(span).is_ok()` and `span_to_snippet(span).is_err()` with it. This removes a `&str` to `String` conversion.
don't allow ZST in ScalarInt
There are several indications that we should not ZST as a ScalarInt:
- We had two ways to have ZST valtrees, either an empty `Branch` or a `Leaf` with a ZST in it.
`ValTree::zst()` used the former, but the latter could possibly arise as well.
- Likewise, the interpreter had `Immediate::Uninit` and `Immediate::Scalar(Scalar::ZST)`.
- LLVM codegen already had to special-case ZST ScalarInt.
So I propose we stop using ScalarInt to represent ZST (which are clearly not integers). Instead, we can add new ZST variants to those types that did not have other variants which could be used for this purpose.
Based on https://github.com/rust-lang/rust/pull/98831. Only the commits starting from "don't allow ZST in ScalarInt" are new.
r? `@oli-obk`
There are several indications that we should not ZST as a ScalarInt:
- We had two ways to have ZST valtrees, either an empty `Branch` or a `Leaf` with a ZST in it.
`ValTree::zst()` used the former, but the latter could possibly arise as well.
- Likewise, the interpreter had `Immediate::Uninit` and `Immediate::Scalar(Scalar::ZST)`.
- LLVM codegen already had to special-case ZST ScalarInt.
So instead add new ZST variants to those types that did not have other variants
which could be used for this purpose.
Clarify MIR semantics of storage statements
Seems worthwhile to start closing out some of the less controversial open questions about MIR semantics. Hopefully this is fairly non-controversial - it's what we implement already, and I see no reason to do anything more restrictive. cc ``@tmiasko`` who commented on this when it was discussed in the original PR that added these docs.
interpret: use AllocRange in UninitByteAccess
also use nice new format string syntax in `interpret/error.rs`, and use the `#` flag to add `0x` prefixes where applicable.
r? ``@oli-obk``
Make MIR basic blocks field public
This makes it possible to mutably borrow different fields of the MIR
body without resorting to methods like `basic_blocks_local_decls_mut_and_var_debug_info`.
To preserve validity of control flow graph caches in the presence of
modifications, a new struct `BasicBlocks` wraps together basic blocks
and control flow graph caches.
The `BasicBlocks` dereferences to `IndexVec<BasicBlock, BasicBlockData>`.
On the other hand a mutable access requires explicit `as_mut()` call.
This makes it possible to mutably borrow different fields of the MIR
body without resorting to methods like `basic_blocks_local_decls_mut_and_var_debug_info`.
To preserve validity of control flow graph caches in the presence of
modifications, a new struct `BasicBlocks` wraps together basic blocks
and control flow graph caches.
The `BasicBlocks` dereferences to `IndexVec<BasicBlock, BasicBlockData>`.
On the other hand a mutable access requires explicit `as_mut()` call.
interpret: remove support for unsized_locals
I added support for unsized_locals in https://github.com/rust-lang/rust/pull/59780 but the current implementation is a crude hack and IMO definitely not the right way to have unsized locals in MIR. It also [causes problems](https://rust-lang.zulipchat.com/#narrow/stream/146212-t-compiler.2Fconst-eval/topic/Missing.20Layout.20Check.20in.20.60interpret.2Foperand.2Ers.60.3F). and what codegen does is unsound and has been for years since clearly nobody cares (so I hope nobody actually relies on that implementation and I'll be happy if Miri ensures they do not). I think if we want to have unsized locals in Miri/MIR we should add them properly, either by having a `StorageLive` that takes metadata or by having an `alloca` that returns a pointer (making the ptr indirection explicit) or something like that.
So, this PR removes the `LocalValue::Unallocated` hack. It adds `Immediate::Uninit`, for several reasons:
- This lets us still do fairly little work in `push_stack_frame`, in particular we do not actually have to create any allocations.
- If/when I remove `ScalarMaybeUninit`, we will need something like this to have an "optimized" representation of uninitialized locals. Without this we'd have to put uninitialized integers into the heap!
- const-prop needs some way to indicate "I don't know the value of this local'; it used to use `LocalValue::Unallocated` for that, now it can use `Immediate::Uninit`.
There is still a fundamental difference between `LocalValue::Unallocated` and `Immediate::Uninit`: the latter is considered a regular local that you can read from and write to, it just has a more optimized representation when compared with an actual `Allocation` that is fully uninit. In contrast, `LocalValue::Unallocated` had this really odd behavior where you would write to it but not read from it. (This is in fact what caused the problems mentioned above.)
While at it I also did two drive-by cleanups/improvements:
- In `pop_stack_frame`, do the return value copying and local deallocation while the frame is still on the stack. This leads to better error locations being reported. The old errors were [sometimes rather confusing](https://rust-lang.zulipchat.com/#narrow/stream/269128-miri/topic/Cron.20Job.20Failure.202022-06-24/near/287445522).
- Deduplicate `copy_op` and `copy_op_transmute`.
r? `@oli-obk`
Operand::Uninit is an *allocated* operand that is fully uninitialized.
This lets us lazily allocate the actual backing store of *all* locals (no matter their ABI).
I also reordered things in pop_stack_frame at the same time.
I should probably have made that a separate commit...
Change enum->int casts to not go through MIR casts.
follow-up to https://github.com/rust-lang/rust/pull/96814
this simplifies all backends and even gives LLVM more information about the return value of `Rvalue::Discriminant`, enabling optimizations in more cases.
fix interpreter validity check on Box
Follow-up to https://github.com/rust-lang/rust/pull/98554: avoid walking over parts of the value twice.
And then move all that logic into the general visitor so not each visitor implementation has to deal with it...
Interpret: AllocRange Debug impl, and use it more consistently
The two commits are pretty independent but it did not seem worth having two PRs for them.
r? ``@oli-obk``
interpret: don't rely on ScalarPair for overflowed arithmetic
This is for https://github.com/rust-lang/rust/pull/97861.
Cc `@eddyb`
I would like to avoid making this depend on `dest.layout.abi` to avoid a branch that we are not usually covering both sides of. Though OTOH this seems like fairly straight-forward code. But let's benchmark this option first to see how bad that extra `force_allocation` really is.
CTFE interning: don't walk allocations that don't need it
The interning of const allocations visits the mplace looking for references to intern. Walking big aggregates like big static arrays can be costly, so we only do it if the allocation we're interning contains references or interior mutability.
Walking ZSTs was avoided before, and this optimization is now applied to cases where there are no references/relocations either.
---
While initially looking at this in the context of #93215, I've been testing with smaller allocations than the 16GB one in that issue, and with different init/uninit patterns (esp. via padding).
In that example, by default, `eval_to_allocation_raw` is the heaviest query followed by `incr_comp_serialize_result_cache`. So I'll show numbers when incremental compilation is disabled, to focus on the const allocations themselves at 95% of the compilation time, at bigger array sizes on these minimal examples like `static ARRAY: [u64; LEN] = [0; LEN];`.
That is a close construction to parts of the `ctfe-stress-test-5` benchmark, which has const allocations in the megabytes, while most crates usually have way smaller ones. This PR will have the most impact in these situations, as the walk during the interning starts to dominate the runtime.
Unicode crates (some of which are present in our benchmarks) like `ucd`, `encoding_rs`, etc come to mind as having bigger than usual allocations as well, because of big tables of code points (in the hundreds of KB, so still an order of magnitude or 2 less than the stress test).
In a check build, for a single static array shown above, from 100 to 10^9 u64s (for lengths in powers of ten), the constant factors are lowered:
(log scales for easier comparisons)
(linear scale for absolute diff at higher Ns)
For one of the alternatives of that issue
```rust
const ROWS: usize = 100_000;
const COLS: usize = 10_000;
static TWODARRAY: [[u128; COLS]; ROWS] = [[0; COLS]; ROWS];
```
we can see a similar reduction of around 3x (from 38s to 12s or so).
For the same size, the slowest case IIRC is when there are uninitialized bytes e.g. via padding
```rust
const ROWS: usize = 100_000;
const COLS: usize = 10_000;
static TWODARRAY: [[(u64, u8); COLS]; ROWS] = [[(0, 0); COLS]; ROWS];
```
then interning/walking does not dominate anymore (but means there is likely still some interesting work left to do here).
Compile times in this case rise up quite a bit, and avoiding interning walks has less impact: around 23%, from 730s on master to 568s with this PR.
Enable MIR inlining
Continuation of https://github.com/rust-lang/rust/pull/82280 by `@wesleywiser.`
#82280 has shown nice compile time wins could be obtained by enabling MIR inlining.
Most of the issues in https://github.com/rust-lang/rust/issues/81567 are now fixed,
except the interaction with polymorphization which is worked around specifically.
I believe we can proceed with enabling MIR inlining in the near future
(preferably just after beta branching, in case we discover new issues).
Steps before merging:
- [x] figure out the interaction with polymorphization;
- [x] figure out how miri should deal with extern types;
- [x] silence the extra arithmetic overflow warnings;
- [x] remove the codegen fulfilment ICE;
- [x] remove the type normalization ICEs while compiling nalgebra;
- [ ] tweak the inlining threshold.
interpret: make a comment less scary
This slipped past my review: "has no meaning" could be read as "is undefined behavior". That is certainly not what we mean so be more clear.
cleanup mir visitor for `rustc::pass_by_value`
by changing `& $($mutability)?` to `$(& $mutability)?`
I also did some formatting changes because I started doing them for the visit methods I changed and then couldn't get myself to stop xx, I hope that's still fairly easy to review.
Const eval no longer runs MIR optimizations so unless this is getting
run as part of a MIR optimization like const-prop, there can be unused
type parameters even if polymorphization is enabled.
interpret: add From<&MplaceTy> for PlaceTy
We have a similar instance for `&MPlaceTy` to `OpTy`. Also add the same for `&mut`.
This avoids having to write `&(*place).into()`, which we have a few times here and at least twice in Miri (and it comes up again in my current patch).
r? ```@oli-obk```
interpret: do not prune requires_caller_location stack frames quite so early
https://github.com/rust-lang/rust/pull/87000 made the interpreter skip `caller_location` frames for its stacktraces and `cur_span`. However, those functions are used for much more than just panic reporting, and e.g. when Miri reports UB somewhere, it probably wants to point inside `caller_location` frames. (And if it did not, it would want to have its own logic to decide that, not be forced into it by the core interpreter engine.) This fixes some rare ICEs in Miri that say "we should never pop more than one frame at once".
So let's remove all `caller_location` logic from the core interpreter, and instead move it to CTFE error reporting. This does not change user-visible behavior. That's the first commit.
We might additionally want to change CTFE error reporting to treat panics differently from other errors: only prune `caller_location` frames for panics. The second commit does that. But honestly I am not sure if this is an improvement.
r? ``@oli-obk``
Checking the size/alignment of an mplace may be costly, so we only do it
on the types where the walk we want to avoid could be expensive: the larger types
like arrays and slices, rather than on all aggregates being interned.
Reorganizes the previous commits to have a single exit-point to avoid doing the
potentially costly walk. Also moves the relocations tests before the interior
mutability test: only references are important when checking for `UnsafeCell`s
and we're checking if there are any to decide to avoid the walk anyways.
The interning of const allocations visits the mplace looking for references
to intern. Walking big aggregates like big static arrays can be costly,
so we only do it if the allocation we're interning contains references
or interior mutability.
Walking ZSTs was avoided before, and this optimization is now applied
to cases where there are no references/relocations either.
We now have an infallible function that also tells us which kind of allocation we are talking about.
Also we do longer have to distinguish between data and function allocations for liveness.
Remove dereferencing of Box from codegen
Through #94043, #94414, #94873, and #95328, I've been fixing issues caused by Box being treated like a pointer when it is not a pointer. However, these PRs just introduced special cases for Box. This PR removes those special cases and instead transforms a deref of Box into a deref of the pointer it contains.
Hopefully, this is the end of the Box<T, A> ICEs.
The current code is a basis for `is_const_fn_raw`, and `impl_constness`
is no longer a valid name, which is previously used for determining the
constness of impls, and not items in general.
And likewise for the `Const::val` method.
Because its type is called `ConstKind`. Also `val` is a confusing name
because `ConstKind` is an enum with seven variants, one of which is
called `Value`. Also, this gives consistency with `TyS` and `PredicateS`
which have `kind` fields.
The commit also renames a few `Const` variables from `val` to `c`, to
avoid confusion with the `ConstKind::Value` variant.
Remove unnecessary `to_string` and `String::new`
73fa217bc1 changed the type of the `suggestion` argument to `impl ToString`. This patch removes unnecessary `to_string` and `String::new`.
cc: `````@davidtwco`````
interpret: unify offset_from check with offset check
`offset` does the check with a single `check_ptr_access` call while `offset_from` used two calls. Make them both just one one call.
I originally intended to actually factor this into a common function, but I am no longer sure if that makes a lot of sense... the two functions start with pretty different precondition (e.g. `offset` *knows* that the 2nd pointer has the same provenance).
I also reworded the UB messages a little. Saying it "cannot" do something is not how we usually phrase UB (as far as I know). Instead it's not *allowed* to do that.
r? ``````@oli-obk``````
use precise spans for recursive const evaluation
This fixes https://github.com/rust-lang/rust/issues/73283 by using a `TyCtxtAt` with a more precise span when the interpreter recursively calls itself. Hopefully such calls are sufficiently rare that this does not cost us too much performance.
(In theory, cycles can also arise through layout computation, as layout can depend on consts -- but layout computation happens all the time so we'd have to do something to not make this terrible for performance.)
This commit makes type folding more like the way chalk does it.
Currently, `TypeFoldable` has `fold_with` and `super_fold_with` methods.
- `fold_with` is the standard entry point, and defaults to calling
`super_fold_with`.
- `super_fold_with` does the actual work of traversing a type.
- For a few types of interest (`Ty`, `Region`, etc.) `fold_with` instead
calls into a `TypeFolder`, which can then call back into
`super_fold_with`.
With the new approach, `TypeFoldable` has `fold_with` and
`TypeSuperFoldable` has `super_fold_with`.
- `fold_with` is still the standard entry point, *and* it does the
actual work of traversing a type, for all types except types of
interest.
- `super_fold_with` is only implemented for the types of interest.
Benefits of the new model.
- I find it easier to understand. The distinction between types of
interest and other types is clearer, and `super_fold_with` doesn't
exist for most types.
- With the current model is easy to get confused and implement a
`super_fold_with` method that should be left defaulted. (Some of the
precursor commits fixed such cases.)
- With the current model it's easy to call `super_fold_with` within
`TypeFolder` impls where `fold_with` should be called. The new
approach makes this mistake impossible, and this commit fixes a number
of such cases.
- It's potentially faster, because it avoids the `fold_with` ->
`super_fold_with` call in all cases except types of interest. A lot of
the time the compile would inline those away, but not necessarily
always.
Rollup of 5 pull requests
Successful merges:
- #97312 (Compute lifetimes in scope at diagnostic time)
- #97495 (Add E0788 for improper #[no_coverage] usage)
- #97579 (Avoid creating `SmallVec`s in `global_llvm_features`)
- #97767 (interpret: do not claim UB until we looked more into variadic functions)
- #97787 (E0432: rust 2018 -> rust 2018 or later in --explain message)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
interpret: better control over whether we read data with provenance
The resolution in https://github.com/rust-lang/unsafe-code-guidelines/issues/286 seems to be that when we load data at integer type, we implicitly strip provenance. So let's implement that in Miri at least for scalar loads. This makes use of the fact that `Scalar` layouts distinguish pointer-sized integers and pointers -- so I was expecting some wild bugs where layouts set this incorrectly, but so far that does not seem to happen.
This does not entirely implement the solution to https://github.com/rust-lang/unsafe-code-guidelines/issues/286; we still do the wrong thing for integers in larger types: we will `copy_op` them and then do validation, and validation will complain about the provenance. To fix that we need mutating validation; validation needs to strip the provenance rather than complaining about it. This is a larger undertaking (but will also help resolve https://github.com/rust-lang/miri/issues/845 since we can reset padding to `Uninit`).
The reason this is useful is that we can now implement `addr` as a `transmute` from a pointer to an integer, and actually get the desired behavior of stripping provenance without exposing it!
take back half-baked noaliasing check in Assignment
Doing an aliasing check in `copy_op` does not make a ton of sense. We have to eventually do something in the `Assignment` statement handling instead.
rename PointerAddress → PointerExposeAddress
`PointerAddress` sounds a bit too much like `ptr.addr()`, but this corresponds to `ptr.expose_addr()`.
r? `@tmiasko`
Ensure we never consider the null pointer dereferencable
This replaces the checks that are being removed in https://github.com/rust-lang/rust/pull/97188. Those checks were too early and hence incorrect.
Miri call ABI check: ensure type size+align stay the same
We should almost certainly not accept calls where caller and callee disagree on the size or alignment of the type.
The checks we do *almost* imply that, except that `ScalarPair` types can have `repr(align)` and thus differ in size/align even when they are pairs of the same primitive type.
r? ``@oli-obk``
Add validation layer for Derefer
_Follow up work to #96549#96116#95857 #95649_
This adds validation for Derefer making sure it is always the first projection.
r? rust-lang/mir-opt
Replace `#[default_method_body_is_const]` with `#[const_trait]`
pulled out of #96077
related issues: #67792 and #92158
cc `@fee1-dead`
This is groundwork to only allowing `impl const Trait` for traits that are marked with `#[const_trait]`. This is necessary to prevent adding a new default method from becoming a breaking change (as it could be a non-const fn).
Move various checks to typeck so them failing causes the typeck result to get tainted
Fixes#69487fixes#79047
cc `@RalfJung` this gets rid of the `Transmute` invalid program error variant
