This ensures that the entry function is never elided due to inlining, even with `inline(always)`. Fixes#47783.
There were a couple of possible ways of addressing this issue; I simply picked the one that seemed most direct. A warning could be appropriate, but considering using inlining hints in other places it doesn't apply also throws no warnings, and it seems like an edge case anyway, I haven't added one for now.
Introduce UnpackedKind
This adds an `UnpackedKind` type as a typesafe counterpart to `Kind`. This should make future changes to kinds (such as const generics!) more resilient, as the type-checker will be able to catch more potential issues.
r? @eddyb
cc @yodaldevoid
Allow for instantiating statics from upstream crates
This PR makes the infrastructure around translating statics a bit more flexible so that it can also instantiate statics from upstream crates if the need arises. This is preparatory work for a MIR-only RLIBs prototype, where the instantiation of a `static` may be deferred until a leaf crate.
r? @eddyb (feel free to assign to someone else if you're busy)
rustc_mir: handle all aggregate kinds in, and always run, the deaggregator.
This helps with removing`Rvalue::Aggregate` from the MIR, and with enabling more optimizations.
r? @nikomatsakis
This adds an `UnpackedKind` type as a typesafe counterpart to `Kind`. This should make future changes to kinds (such as const generics!) more resilient, as the type-checker should catch more potential issues.
You can now choose between the following:
- `#[unwind(allowed)]`
- `#[unwind(aborts)]`
Per rust-lang/rust#48251, the default is `#[unwind(allowed)]`, though
I think we should change this eventually.
Don't promote to 'static the result of dereferences.
This is a **breaking change**, removing copies out of dereferences from rvalue-to-`'static` promotion.
With miri we won't easily know whether the dereference itself would see the same value at runtime as miri (e.g. after mutating a `static`) or even if it can be interpreted (e.g. integer pointers).
One alternative to this ban is defining at least *some* of those situations as UB, i.e. you shouldn't have a reference in the first place, and you should work through raw pointers instead, to avoid promotion.
**EDIT**: The other *may seem* to be to add some analysis which whitelists references-to-constant-values and assume any values produced by arbitrary computation to not be safe to promote dereferences thereof - but that means producing a reference from an associated constant or `const fn` would necessarily obscure it, and in the former case, this could still impact code that runs on stable today. What we do today to track "references to statics" only works because we restrict taking a reference to a `static` at all to other `static`s (which, again, are currently limited in that they can't be read at compile-time) and to runtime-only `fn`s (*not* `const fn`s).
I'm primarily opening this PR with a conservative first approximation (e.g. `&(*r).a` is not allowed, only reborrows are, and in the old borrow only implicit ones from adjustments, at that) for cratering.
r? @nikomatsakis
rustc_mir: insert a dummy access to places being matched on, when building MIR.
Fixes#47412 by adding a `_dummy = Discriminant(place)` before each `match place {...}`.
r? @nikomatsakis
Disallow function pointers to #[rustc_args_required_const]
This commit disallows acquiring a function pointer to functions tagged as
`#[rustc_args_required_const]`. This is intended to be used as future-proofing
for the stdsimd crate to avoid taking a function pointer to any intrinsic which
has a hard requirement that one of the arguments is a constant value.
Note that the first commit here isn't related specifically to this feature, but was necessary to get this working in stdsimd!
[NLL] Add false edges out of infinite loops
Resolves#46036 by adding a `cleanup` member to the `FalseEdges` terminator kind. There's also a small doc fix to one of the other comments in `into.rs` which I can pull out in to another PR if desired =)
This PR should pass CI but the test suite has been relatively unstable on my system so I'm not 100% sure.
r? @nikomatsakis
NLL: Limit two-phase borrows to autoref-introduced borrows
This imposes a restriction on two-phase borrows so that it only applies to autoref-introduced borrows.
The goal is to ensure that our initial deployment of two-phase borrows is very conservative. We want it to still cover the `v.push(v.len());` example, but we do not want it to cover cases like `let imm = &v; let mu = &mut v; mu.push(imm.len());`
(Why do we want it to be conservative? Because when you are not conservative, then the results you get, at least with the current analysis, are tightly coupled to details of the MIR construction that we would rather remain invisible to the end user.)
Fix#46747
I decided, for this PR, to add a debug-flag `-Z two-phase-beyond-autoref`, to re-enable the more general approach. But my intention here is *not* that we would eventually turn on that debugflag by default; the main reason I added it was that I thought it was useful for writing tests to be able to write source that looks like desugared MIR.
This commit disallows acquiring a function pointer to functions tagged as
`#[rustc_args_required_const]`. This is intended to be used as future-proofing
for the stdsimd crate to avoid taking a function pointer to any intrinsic which
has a hard requirement that one of the arguments is a constant value.
Namely, the mutable borrows also carries a flag indicating whether
they should support two-phase borrows.
This allows us to thread down, from the point of the borrow's
introduction, whether the particular adjustment that created it is one
that yields two-phase mutable borrows.
Added `-Z two-phase-beyond-autoref` to bring back old behavior (mainly
to allow demonstration of desugared examples).
Updated tests to use aforementioned flag when necessary. (But in each
case where I added the flag, I made sure to also include a revision
without the flag so that one can readily see what the actual behavior
we expect is for the initial deployment of NLL.)
As opposed to using weirdness involving pretending the body block
is the loop block. This does not pass tests
This commit is [ci skip] because I know it doesn't pass tests yet.
Somehow this commit introduces nondeterminism into the handling of
loops.
rustc: Add `#[rustc_args_required_const]`
This commit adds a new unstable attribute to the compiler which requires that
arguments to a function are always provided as constants. The primary use case
for this is SIMD intrinsics where arguments are defined by vendors to be
constant and in LLVM they indeed must be constant as well.
For now this is mostly just a semantic guarantee in rustc that an argument is a
constant when invoked, phases like trans don't actually take advantage of it
yet. This means that we'll be able to use this in stdsimd but we won't be able
to remove the `constify_*` macros just yet. Hopefully soon though!
[NLL] Improve DefiningTy::Const
Fixes#47590 by fixing the way DefiningTy represents constants. Previously, constants were represented using just the type of the variable. However, this will fail to capture early-bound regions as NLL inference vars, resulting in an ICE when we try to compute region VIDs a little bit later in the universal
region resolution process. (ref #47590)
Fixes#47590 by fixing the way DefiningTy represents constants. Previously,
constants were represented using just the type of the variable. However, this
will fail to capture early-bound regions as NLL inference vars, resulting in an
ICE when we try to compute region VIDs a little bit later in the universal
region resolution process.
MIR-borrowck: augmented assignment causes duplicate errors
Fixes#45697. This PR resolves the error duplication. I attempted to replace the existing sets since there were quite a few but only managed to replace two of them.
r? @nikomatsakis
Sometimes a simple goto misses the cleanup/unwind edges. Specifically, in the
case of infinite loops such as those introduced by a loop statement without any
other out edges. Analogous to TerminatorKind::FalseEdges; this new terminator
kind is used when we want borrowck to consider an unwind path, but real control
flow should never actually take it.
This commit adds a new unstable attribute to the compiler which requires that
arguments to a function are always provided as constants. The primary use case
for this is SIMD intrinsics where arguments are defined by vendors to be
constant and in LLVM they indeed must be constant as well.
For now this is mostly just a semantic guarantee in rustc that an argument is a
constant when invoked, phases like trans don't actually take advantage of it
yet. This means that we'll be able to use this in stdsimd but we won't be able
to remove the `constify_*` macros just yet. Hopefully soon though!
Fix overflow when performing drop check calculations in NLL
Clearing out the infcx's region constraints after processing each type
ends up interacting badly with normalizing associated types. This commit
keeps all region constraints intact until the end of
TypeLivenessGenerator.add_drop_live_constraint, ensuring that normalized
types are able to re-use existing inference variables.
Fixes#47589
Fix ref-to-ptr coercions not working with NLL in certain cases
Implicit coercions from references to pointers were lowered to slightly
different Mir than explicit casts (e.g. 'foo as *mut T'). This resulted
in certain uses of self-referential structs compiling correctly when an
explicit cast was used, but not when the implicit coercion was used.
To fix this, this commit adds an outer 'Use' expr when applying a
raw-ptr-borrow adjustment. This makes the lowered Mir for coercions
identical to that of explicit coercions, allowing the original code to
compile regardless of how the raw ptr cast occurs.
Fixes#47722
Cleanup the shim code
- We now write directly to `RETURN_PLACE` instead of creating intermediates
- `tuple_like_shim` takes an iterator (used by #47867)
- `tuple_like_shim` no longer relies on it being the first thing to create blocks, and uses relative block indexing in a cleaner way (necessary for #47867)
- All the shim builders take `dest, src` arguments instead of hardcoding RETURN_PLACE
r? @eddyb
Turn `type_id` into a constant intrinsic
https://github.com/rust-lang/rust/issues/27745
The method `get_type_id` in `Any` is intended to support reflection. It's currently unstable in favor of using an associated constant instead. This PR makes the `type_id` intrinsic a constant intrinsic, the same as `size_of` and `align_of`, allowing `TypeId::of` to be a `const fn`, which will allow using an associated constant in `Any`.
rustc: prefer ParamEnvAnd and LayoutCx over tuples for LayoutOf.
This PR provides `tcx.layout_of(param_env.and(ty))` as the idiomatic replacement for the existing `(tcx, param_env).layout_of(ty)` and removes fragile (coherence-wise) layout-related tuple impls.
r? @nikomatsakis
Clearing out the infcx's region constraints after processing each type
ends up interacting badly with normalizing associated types. This commit
keeps all region constraints intact until the end of
TypeLivenessGenerator.add_drop_live_constraint, ensuring that normalized
types are able to re-use existing inference variables.
Fixes#47589
rustc: Add an option to default hidden visibility
This commit adds a new option to target specifictions to specify that symbols
should be "hidden" visibility by default in LLVM. While there are no existing
targets that take advantage of this the `wasm32-unknown-unknown` target will
soon start to use this visibility. The LLD linker currently interprets `hidden`
as "don't export this from the wasm module" which is what we want for 90% of our
functions. While the LLD linker does have a "export this symbol" argument which
is what we use for other linkers, it was also somewhat easier to do this change
instead which'll involve less arguments flying around. Additionally there's no
need for non-`hidden` visibility for most of our symbols!
This change should not immediately impact the wasm targets as-is, but rather
this is laying the foundations for soon integrating LLD as a linker for wasm
code.
is_unsafe_place only filters out statics in the rhs, not the lhs. Since
it's possible to reach that 'Place::Static', we handle statics the same
way as we do locals.
Fixes#47789
This commit adds a new option to target specifictions to specify that symbols
should be "hidden" visibility by default in LLVM. While there are no existing
targets that take advantage of this the `wasm32-unknown-unknown` target will
soon start to use this visibility. The LLD linker currently interprets `hidden`
as "don't export this from the wasm module" which is what we want for 90% of our
functions. While the LLD linker does have a "export this symbol" argument which
is what we use for other linkers, it was also somewhat easier to do this change
instead which'll involve less arguments flying around. Additionally there's no
need for non-`hidden` visibility for most of our symbols!
This change should not immediately impact the wasm targets as-is, but rather
this is laying the foundations for soon integrating LLD as a linker for wasm
code.
Implicit coercions from references to pointers were lowered to slightly
different Mir than explicit casts (e.g. 'foo as *mut T'). This resulted
in certain uses of self-referential structs compiling correctly when an
explicit cast was used, but not when the implicit coercion was used.
To fix this, this commit adds an outer 'Use' expr when applying a
raw-ptr-borrow adjustment. This makes the lowered Mir for coercions
identical to that of explicit coercions, allowing the original code to
compile regardless of how the raw ptr cast occurs.
Fixes#47722
Fix never-type rvalue ICE
This fixes#43061.
r? @nikomatsakis
A small post-mortem as a follow-up to our investigations in https://github.com/rust-lang/rust/pull/47291:
The problem as I understand it is that when `NeverToAny` coercions are made, the expression/statement that is coerced may be enclosed in a block. In our case, the statement `x;` was being transformed to something like: `NeverToAny( {x;} )`. Then, `NeverToAny` is transformed into an expression:
000fbbc9b8/src/librustc_mir/build/expr/into.rs (L52-L59)
Which ends up calling `ast_block_stmts` on the block `{x;}`, which triggers this condition:
000fbbc9b8/src/librustc_mir/build/block.rs (L141-L147)
In our case, there is no return expression, so `push_assign_unit` is called. But the block has already been recorded as _diverging_, meaning the result of the block will be assigned to a location of type `!`, rather than `()`. This causes the MIR error.
I'm assuming the `NeverToAny` coercion code is doing what it's supposed to (there don't seem to be any other problems), so fixing the issue simply consists of checking that the destination for the return value actually _is_ supposed to be a unit. (If no return value is given, the only other possible type for the return value is `!`, which can just be ignored, as it will be unreachable anyway.)
I checked the other cases of `push_assign_unit`, and it didn't look like they could be affected by the divergence issue (blocks are kind of special-cased in this regard as far as I can tell), so this should be sufficient to fix the issue.
Add CGU size heuristic for partitioning
This addresses the concern of #47316 by estimating CGU size based on
the size of its MIR. Looking at the size estimate differences for a
small selection of crates, this heuristic produces different orderings,
which should more accurately reflect optimisation time. (Fixes #47316.)
r? @michaelwoerister
renumber regions in generators
This fixes#47189, but I think we still have to double check various things around how to treat generators in MIR type check + borrow check (e.g., what borrows should be invalidated by a `Suspend`? What consistency properties should type check be enforcing anyway around the "interior" type?)
Also fixes#47587 thanks to @spastorino's commit.
r? @pnkfelix
Custom error when moving arg outside of its closure
When given the following code:
```rust
fn give_any<F: for<'r> FnOnce(&'r ())>(f: F) {
f(&());
}
fn main() {
let mut x = None;
give_any(|y| x = Some(y));
}
```
provide a custom error:
```
error: borrowed data cannot be moved outside of its closure
--> file.rs:7:27
|
6 | let mut x = None;
| ----- borrowed data cannot be moved into here...
7 | give_any(|y| x = Some(y));
| --- ^ cannot be moved outside of its closure
| |
| ...because it cannot outlive this closure
```
instead of the generic lifetime error:
```
error[E0495]: cannot infer an appropriate lifetime due to conflicting requirements
--> file.rs:7:27
|
7 | give_any(|y| x = Some(y));
| ^
|
note: first, the lifetime cannot outlive the anonymous lifetime #2 defined on the body at 7:14...
--> file.rs:7:14
|
7 | give_any(|y| x = Some(y));
| ^^^^^^^^^^^^^^^
note: ...so that expression is assignable (expected &(), found &())
--> file.rs:7:27
|
7 | give_any(|y| x = Some(y));
| ^
note: but, the lifetime must be valid for the block suffix following statement 0 at 6:5...
--> file.rs:6:5
|
6 | / let mut x = None;
7 | | give_any(|y| x = Some(y));
8 | | }
| |_^
note: ...so that variable is valid at time of its declaration
--> file.rs:6:9
|
6 | let mut x = None;
| ^^^^^
```
Fix#45983.
remove bogus assertion and comments
The code (incorrectly) assumed that constants could not have generics
in scope, but it's not really a problem if they do.
Fixes#47153
r? @pnkfelix
avoid double-unsizing arrays in bytestring match lowering
The match lowering code, when lowering matches against bytestrings,
works by coercing both the scrutinee and the pattern to `&[u8]` and
then comparing them using `<[u8] as Eq>::eq`.
If the scrutinee is already of type `&[u8]`, then unsizing it is both
unneccessary and a trait error caught by the new and updated MIR typeck,
so this PR changes lowering to avoid doing that (match lowering tried to
avoid that before, but that attempt was quite broken).
Fixes#46920.
r? @eddyb
This addresses the concern of #47316 by estimating CGU size based on
the size of its MIR. Looking at the size estimate differences for a
small selection of crates, this heuristic produces different orderings,
which should more accurately reflect optimisation time.
Fixes#47316.
remove noop landing pads in cleanup shims
No-op landing pads are already removed in the normal optimization pipeline - so also removing them on the shim pipeline should slightly improve codegen performance, as these cleanup blocks are known to hurt LLVM.
This un-regresses and is therefore a fix for #47442. However, the reporter of that issue should try using `-C panic=abort` instead of carefully avoiding panics.
r? @eddyb
Add a default directory for -Zmir-dump-dir
The current behaviour of dumping in the current directory is rarely
desirable: a sensible default directory for dumping is much more
convenient. This makes sets the default value for `-Zmir-dump-dir`
to `mir_dump/`.
r? @eddyb
The match lowering code, when lowering matches against bytestrings,
works by coercing both the scrutinee and the pattern to `&[u8]` and
then comparing them using `<[u8] as Eq>::eq`.
If the scrutinee is already of type `&[u8]`, then unsizing it is both
unneccessary and a trait error caught by the new and updated MIR typeck,
so this PR changes lowering to avoid doing that (match lowering tried to
avoid that before, but that attempt was quite broken).
Fixes#46920.
These are already removed in the normal optimization pipeline - so this
should slightly improve codegen performance, as these cleanup blocks are
known to hurt LLVM.
This un-regresses and is therefore a fix for #47442. However, the
reporter of that issue should try using `-C panic=abort` instead of
carefully avoiding panics.
No longer parse it.
Remove AutoTrait variant from AST and HIR.
Remove backwards compatibility lint.
Remove coherence checks, they make no sense for the new syntax.
Remove from rustdoc.
Use the new fs_read_write functions in rustc internals
Uses `fs::read` and `fs::write` (added by #45837) where appropriate, to simplify code and dog-food these new APIs. This also improves performance, when combined with #47324.
Shorten names of some compiler generated artifacts.
This PR makes the compiler mangle codegen unit names by default. The name of every codegen unit name will now be a random string of 16 characters. It also makes the file extensions of some intermediate compiler products shorter. Hopefully, these changes will reduce the pressure on tools with path length restrictions like buildbot. The change should also solve problems with case-insensitive file system.
cc #47186 and #47222
r? @alexcrichton
Make normalize_and_test_predicates into a query
From #44891.
I'm not real solid on how `dep_graph` stuff works, but if a node is going to have a key (again, not sure how important that is), then the key needs to be `Copy`. So since `normalize_and_test_predicates` only had one out-of-module use, I changed that call site to use a new function, `substitute_normalize_and_test_predicates` which is the query and enables having the arguments be `Copy`. Hopefully this makes sense.
r? @nikomatsakis
and/or @michaelwoerister
rustc: use {U,I}size instead of {U,I}s shorthands.
`Us`/`Is` come from a time when `us` and `is` were the literal suffixes that are now `usize` / `isize`.
r? @nikomatsakis
Bump to 1.25.0
* Bump the release version to 1.25
* Bump the bootstrap compiler to the recent beta
* Allow using unstable rustdoc features on beta - this fix has been applied to
the beta branch but needed to go to the master branch as well.
Reword reason for move note
On move errors, when encountering an enum variant, be more ambiguous and do not refer to the type on the cause note, to avoid referring to `(maybe as std::prelude::v1::Some).0`, and instead refer to `the value`.
Sidesteps part of the problem with #41962:
```
error[E0382]: use of partially moved value: `maybe`
--> file.rs:5:30
|
5 | if let Some(thing) = maybe {
| ----- ^^^^^ value used here after move
| |
| value moved here
= note: move occurs because the value has type `std::vec::Vec<bool>`, which does not implement the `Copy` trait
error[E0382]: use of moved value: `(maybe as std::prelude::v1::Some).0`
--> file.rs:5:21
|
5 | if let Some(thing) = maybe {
| ^^^^^ value moved here in previous iteration of loop
= note: move occurs because the value has type `std::vec::Vec<bool>`, which does not implement the `Copy` trait
error: aborting due to 2 previous errors
```
Previous discussion: #44360
r? @arielb1
NLL fixes
First, introduce pre-statement effects to dataflow to fix#46875. Edge dataflow effects might make that redundant, but I'm not sure of the best way to integrate them with liveness etc., and if this is a hack, this is one of the cleanest hacks I've seen.
And I want a small fix to avoid the torrent of bug reports.
Second, fix linking of projections to fix#46974
r? @pnkfelix
Do not expand a derive invocation when derive is not allowed
Closes#46655.
The first commit is what actually closes#46655. The second one is just a refactoring I have done while waiting on a test.
Implements RFC 1937: `?` in `main`
This is the first part of the RFC 1937 that supports new
`Termination` trait in the rust `main` function.
Thanks @nikomatsakis, @arielb1 and all other people in the gitter channel for all your help!
The support for doctest and `#[test]` is still missing, bu as @nikomatsakis said, smaller pull requests are better :)
[MIR Borrowck] Moveck inline asm statements
Closes#45695
New behavior:
* Input operands to `asm!` are moved, direct output operands are initialized.
* Direct, non-read-write outputs match the assignment changes in #46752 (Shallow writes, end borrows).
