rustc_mir: double-check const-promotion candidates for sanity.
Previously, const promotion involved tracking information about the value in a MIR local (or any part of the computation leading up to that value), aka "qualifs", in a quite stateful manner, which is hard to extend to arbitrary CFGs without a dataflow pass.
However, the nature of the promotion we do is that it's effectively an SSA-like "tree" (or DAG, really), of assigned-once locals - which is how we can take them from the original MIR in the first place.
This structure means that the subset of the MIR responsible for computing any given part of a const-promoted value is readily analyzable by walking that tree/DAG.
This PR implements such an analysis in `promote_consts`, reusing the `HasMutInterior` / `NeedsDrop` computation from `qualify_consts`, but reimplementing the equivalent of `IsNotPromotable` / `IsNotImplicitlyPromotable`.
Eventually we should be able to remove `IsNotPromotable` / `IsNotImplicitlyPromotable` from `qualify_consts`, which will simplify @ecstatic-morse's dataflow-based const-checking efforts.
But currently this is mainly for a crater check-only run - it will compare the results from the old promotion collection and the new promotion validation and ICE if they don't match.
r? @oli-obk
This is leftover from a restructuring of lint registration for drivers;
it should now happen via the register_lints field on Config rather than
this function.
SGX: Clear additional flag on enclave entry
An attacker could set both the AC flag in CR0 as in rflags. This causes the enclave to perform an AEX upon a misaligned memory access, and an attacker learns some information about the internal enclave state.
The AC flag in rflags is copied from userspace upon an enclave entry. Upon AEX it is copied and later restored. This patch forces the rflag.AC bit to be reset right after an enter.
self-profiling: Update measureme to 0.4.0 and remove non-RAII methods from profiler.
This PR removes all non-RAII based profiling methods from `SelfProfilerRef` 🎉
It also delegates the `TimingGuard` implementation to `measureme`, now that that is available there.
r? @wesleywiser
Insurance policy in case `iter.size_hint()` lies.
Follow up to https://github.com/rust-lang/rust/pull/64949/files#r334235076.
(If the perf impact is bad we can use `debug_assert!` instead.)
The good news is that the UI tests pass locally so `iter.size_hint()` seems to be honest *thus far*.
On the other hand, with the status quo we do not have an insurance policy should that change in some case. This is problematic because a) this could possibly make some program be accepted which shouldn't, b) the compiler itself could have memory unsafety if the correctness of the iterator is assumed in `unsafe { ... }` code (even though the blame lies with the `unsafe { ... }` block in question.)
r? @RalfJung
cc @nnethercote
(Or more precisely, a pair of such traits: one for `derive(PartialEq)` and one
for `derive(Eq)`.)
((The addition of the second marker trait, `StructuralEq`, is largely a hack to
work-around `fn (&T)` not implementing `PartialEq` and `Eq`; see also issue
rust-lang/rust#46989; otherwise I would just check if `Eq` is implemented.))
Note: this does not use trait fulfillment error-reporting machinery; it just
uses the trait system to determine if the ADT was tagged or not. (Nonetheless, I
have kept an `on_unimplemented` message on the new trait for structural_match
check, even though it is currently not used.)
Note also: this does *not* resolve the ICE from rust-lang/rust#65466, as noted
in a comment added in this commit. Further work is necessary to resolve that and
other problems with the structural match checking, especially to do so without
breaking stable code (adapted from test fn-ptr-is-structurally-matchable.rs):
```rust
fn r_sm_to(_: &SM) {}
fn main() {
const CFN6: Wrap<fn(&SM)> = Wrap(r_sm_to);
let input: Wrap<fn(&SM)> = Wrap(r_sm_to);
match Wrap(input) {
Wrap(CFN6) => {}
Wrap(_) => {}
};
}
```
where we would hit a problem with the strategy of unconditionally checking for
`PartialEq` because the type `for <'a> fn(&'a SM)` does not currently even
*implement* `PartialEq`.
----
added review feedback:
* use an or-pattern
* eschew `return` when tail position will do.
* don't need fresh_expansion; just add `structural_match` to appropriate `allow_internal_unstable` attributes.
also fixed example in doc comment so that it actually compiles.
Fix default "disable-shortcuts" feature value
Follow-up of https://github.com/rust-lang/rust/pull/65656
It fixes the bad handling of the default value of the feature (which would disable shortcut by default, which is bad!).
r? @Dylan-DPC
cc @kinnison
Prevent unnecessary allocation in PathBuf::set_extension.
It was allocating a new `OsString` that was immediately dropped after using it with `set_file_name`. Now it directly changes the extension in the original buffer, without touching the rest of the file name or allocating a temporary string.
Fix check of `statx` and handle EPERM
Should fix#65662https://github.com/rust-lang/rust/issues/65662#issuecomment-544593939
> I think a reasonable solution might be to do something like try to stat AT_CWD initially and if that fails with EPERM or ENOSYS we disable the syscall entirely, otherwise it's cached as always good to use.
r? @alexcrichton
Intern place projection
This should sit on top of https://github.com/rust-lang/rust/pull/65197. After that one merged, I'm gonna rebase on top of it.
The important commits are the last three and there's a bunch of code repetition that I'm going to remove but for that I need to refactor some things that probably need to be added before this PR.
Anyway this work helps as is because we can run perf tests :).
r? @oli-obk /cc @nikomatsakis
Fix the start/end byte positions in the compiler JSON output
Track the changes made during normalization in the `SourceFile` and use this information to correct the `start_byte` and `end_byte` fields in the JSON output.
This should ensure the start/end byte fields can be used to index the original file, even if Rust normalized the source code for parsing purposes. Both CRLF to LF and BOM removal are handled with this one.
The rough plan was discussed with @matklad in rust-lang-nursery/rustfix#176 - although I ended up going with `u32` offset tracking so I wouldn't need to deal with `u32 + i32` arithmetics when applying the offset to the span byte positions.
Fixes#65029
Stabilize `#[non_exhaustive]` (RFC 2008)
Fixes#44109.
This pull request stabilizes the `#[non_exhaustive]` attribute, which is used to indicate that a type will have more fields / variants added in the future. It can be applied to `struct`s, `enum`s and `enum` variants. See https://github.com/rust-lang/rust/issues/44109#issuecomment-533356866 for the stabilization report.
r? @Centril
