Add some regression tests
Closes#64848 (fixed by #67631)
Closes#65918 (ICE is hidden by #67000, no longer ICE)
Closes#66473 (fixed by #68084)
Closes#67550 (set mir-opt-level to 3)
r? @Centril
Treat extern statics just like statics in the "const pointer to static" representation
fixes#67612
r? @spastorino
cc @RalfJung this does not affect runtime promotion at all. This is just about promotion within static item bodies.
* Removes unnecessary feature flag from track_caller test.
* Tests of panic internals no longer need to explicitly construct Location.
* Add #![warn(const_err)] to retain-never-const per @oli-obk.
* Add track_caller test with diverging function.
This extends the invalid cases we catch in const prop to include
overflowing integer casts using the same machinery as the overflowing
binary and unary operation logic.
We only want to return specializations when `Reveal::All` is passed, not
when `Reveal::UserFacing` is. Resolving this fixes several issues with
the `ConstProp`, `SimplifyBranches`, and `Inline` MIR optimization
passes.
Fixes#66901
`hir::BorrowKind::Raw` borrows and casting a reference to a raw
pointer no longer do a reborrow followed by a cast. Instead we
dereference and take the address.
Remove uniform array move MIR passes
This PR fixes a number of bugs caused by limitations of this pass
* Projections from constant indexes weren't being canonicalized
* Constant indexes from the start weren't being canonicalized (they could have different min_lengths)
* It didn't apply to non-moves
This PR makes the following changes to support removing this pass:
* ConstantIndex of arrays are now generated in a canonical form (from the start, min_length is the actual length).
* Subslices are now split when generating move paths and when checking subslices have been moved.
Additionally
* The parent move path of a projection from an array element is now calculated correctly
closes#66502
These passes were buggy, MIR building is now responsible for
canonicalizing `ConstantIndex` projections and `MoveData` is responsible
for splitting `Subslice` projections.
We now only propagate a scalar pair if the Rvalue is a tuple with two
scalars. This for example avoids propagating a (u8, u8) value when
Rvalue has type `((), u8, u8)` (see the regression test). While this is
a correct thing to do, implementation is tricky and will be done later.
Fixes#66971Fixes#66339Fixes#67019
rustc: hide HirId's fmt::Debug output from -Z span_free_formats.
This replaces the only occurrences of `HirId {...}` from tests with paths, i.e.:
```rust
[closure@HirId { owner: DefIndex(4), local_id: 15 } q:&i32, t:&T]
```
becomes, after this PR:
```rust
[closure@foo<T>::{{closure}}#0 q:&i32, t:&T]
```
r? @oli-obk cc @michaelwoerister
Handle statics in MIR as const pointers
This is the first PR towards the goal of removing `PlaceBase::Static`. In this PR:
* Statics are lowered to dereferencing a const pointer.
* The temporaries holding such pointers are tracked in MIR, for the most part this is only used for diagnostics. There are two exceptions:
* The borrow checker has some checks for thread-locals that directly use this data.
* Const checking will suppress "cannot dereference raw pointer" diagnostics for pointers to `static mut`/`extern static`. This is to maintain the current behaviour (12 tests fail otherwise).
The following are left to future PRs (I think that @spastorino will be working on the first 3):
* Applying the same treatments to promoted statics.
* Removing `PlaceBase::Static`.
* Replacing `PlaceBase` with `Local`.
* Moving the ever growing collection of metadata that we have for diagnostics in MIR passes somewhere more appropriate.
r? @oli-obk
This optimization depends on inlining for the identity
conversions introduced by the lowering of the `?`.
To take advantage of `SimplifyArmIdentity`, `-Z mir-opt-level=2`
is required because that triggers the inlining MIR optimization.
Split ConstValue into two enums
Hello,
Issue #59210 appeared abandoned, so I gave it a go.
Some further cleanup and refactoring may be mandated.
I did not test beyond `x.py check`, since my home computer dies compiling librustc.
Fixes#59210
An expression like `x[1][{ x = y; 2}]` would perform the bounds check
for the inner index operation before evaluating the outer index. This
would allow out of bounds memory accesses.
[mir-opt] Handle return place in ConstProp and improve SimplifyLocals pass
Temporarily rebased on top of #66074. The top 2 commits are new.
r? @oli-obk
[mir-opt] Implement pass to remove branches on uninhabited variants
Based on discussion [here](https://github.com/rust-lang/rust/pull/64890#discussion_r333612125), this is a pass to eliminate dead code that is caused by branching on an enum with uninhabited variants.
r? @oli-obk
Fix `-Zunpretty=mir-cfg` to render multiple items
`-Zunpretty=mir-cfg` outputs DOT to stdout for all items being compiled. However, it puts all of these items in separate `digraph`s, which means the result of redirecting that output to a file is not valid. Most dot renderers (I have tried `dot` and `xdot`) cannot render the output.
This PR checks to see if `write_mir_graphviz` will process multiple items, and writes them each as a `subgraph` in a single, top-level `digraph`. As a result, DOT can be viewed without manually editing the output file. The output is unchanged when printing a single item (e.g.`-Zunpretty=mir-cfg=item_name`).
Here's the output of `xdot` for a rust file containing three items:
The borders are a result of the nonstandard–but well-supported–[`cluster` prefix](https://graphviz.gitlab.io/_pages/doc/info/lang.html) (search for "Subgraphs and Clusters"). They will not appear if your renderer does not support this extension, but the graph will still render properly.
