Always run intrinsics lowering pass
Move intrinsics lowering pass from the optimization phase (where it
would not run if -Zmir-opt-level=0), to the drop lowering phase where it
runs unconditionally.
The implementation of those intrinsics in code generation and
interpreter is unnecessary. Remove it.
Fixed conflict with drop elaboration and coverage
See
https://github.com/rust-lang/rust/issues/80045#issuecomment-745733339
Coverage statements are moved to the beginning of the BCB. This does
also affect what's counted before a panic, changing some results, but I
think these results may even be preferred? In any case, there are no
guarantees about what's counted when a panic occurs (by design).
r? `@tmandry`
FYI `@wesleywiser` `@ecstatic-morse`
Fix issue #78496
EarlyOtherwiseBranch finds MIR structures like:
```
bb0: {
...
_2 = discriminant(X)
...
switchInt(_2) -> [1_isize: bb1, otherwise: bb3]
}
bb1: {
...
_3 = discriminant(Y)
...
switchInt(_3) -> [1_isize: bb2, otherwise: bb3]
}
bb2: {...}
bb3: {...}
```
And transforms them into something like:
```
bb0: {
...
_2 = discriminant(X)
_3 = discriminant(Y)
_4 = Eq(_2, _3)
switchInt(_4) -> [true: bb4, otherwise: bb3]
}
bb2: {...} // unchanged
bb3: {...} // unchanged
bb4: {
switchInt(_2) -> [1_isize: bb2, otherwise: bb3]
}
```
But that is not always a safe thing to do -- sometimes the early `otherwise` branch is necessary so the later block could assume the value of `discriminant(X)`.
I am not totally sure what's the best way to detect that, but fixing #78496 should be easy -- we just check if `X` is a sub-expression of `Y`. A more precise test might be to check if `Y` contains a `Downcast(1)` of `X`, but I think this might be good enough.
Fix#78496
See
https://github.com/rust-lang/rust/issues/80045#issuecomment-745733339
Coverage statements are moved to the beginning of the BCB. This does
also affect what's counted before a panic, changing some results, but I
think these results may even be preferred? In any case, there are no
guarantees about what's counted when a panic occurs (by design).
make MIR graphviz generation use gsgdt
gsgdt [https://crates.io/crates/gsgdt] is a crate which provides an
interface for stringly typed graphs. It also provides generation of
graphviz dot format from said graph.
This is the first in a series of PRs on moving graphviz code out of rustc into normal crates and then implementating graph diffing on top of these crates.
r? `@oli-obk`
Fixes reported bugs in Rust Coverage
Fixes: #79569Fixes: #79566Fixes: #79565
For the first issue (#79569), I got hit a `debug_assert!()` before
encountering the reported error message (because I have `debug = true`
enabled in my config.toml).
The assertion showed me that some `SwitchInt`s can have more than one
target pointing to the same `BasicBlock`.
I had thought that was invalid, but since it seems to be possible, I'm
allowing this now.
I added a new test for this.
----
In the last two cases above, both tests (intentionally) fail to compile,
but the `InstrumentCoverage` pass is invoked anyway.
The MIR starts with an `Unreachable` `BasicBlock`, which I hadn't
encountered before. (I had assumed the `InstrumentCoverage` pass
would only be invoked with MIRs from successful compilations.)
I don't have test infrastructure set up to test coverage on files that
fail to compile, so I didn't add a new test.
r? `@tmandry`
FYI: `@wesleywiser`
consider assignments of union field of ManuallyDrop type safe
Assigning to `Copy` union fields is safe because that assignment will never drop anything. However, with https://github.com/rust-lang/rust/pull/77547, unions may also have `ManuallyDrop` fields, and their assignments are currently still unsafe. That seems unnecessary though, as assigning `ManuallyDrop` does not drop anything either, and is thus safe even for union fields.
I assume this will at least require FCP.
[mir-opt] Allow debuginfo to be generated for a constant or a Place
Prior to this commit, debuginfo was always generated by mapping a name
to a Place. This has the side-effect that `SimplifyLocals` cannot remove
locals that are only used for debuginfo because their other uses have
been const-propagated.
To allow these locals to be removed, we now allow debuginfo to point to
a constant value. The `ConstProp` pass detects when debuginfo points to
a local with a known constant value and replaces it with the value. This
allows the later `SimplifyLocals` pass to remove the local.
Move intrinsics lowering pass from the optimization phase (where it
would not run if -Zmir-opt-level=0), to the drop lowering phase where it
runs unconditionally.
The implementation of those intrinsics in code generation and
interpreter is unnecessary. Remove it.
Adds checks for:
* `no_core` attribute
* explicitly-enabled `legacy` symbol mangling
* mir_opt_level > 1 (which enables inlining)
I removed code from the `Inline` MIR pass that forcibly disabled
inlining if `-Zinstrument-coverage` was set. The default `mir_opt_level`
does not enable inlining anyway. But if the level is explicitly set and
is greater than 1, I issue a warning.
The new warnings show up in tests, which is much better for diagnosing
potential option conflicts in these cases.
Remove an unused dependency that made `rustdoc` crash
Whilst struggling with https://github.com/rust-lang/rust/issues/79980 I discovered that this dependency was unused, and that made rustdoc crash. This PR removes it.
fix more clippy::complexity findings
fix clippy::unnecessary_filter_map
use if let Some(x) = .. instead of ...map(|x|) to conditionally run fns that return () (clippy::option_map_unit_fn)
fix clippy::{needless_bool, manual_unwrap_or}
don't clone types that are copy (clippy::clone_on_copy)
don't convert types into identical types with .into() (clippy::useless_conversion)
use strip_prefix over slicing (clippy::manual_strip)
r? ``@Dylan-DPC``
Fixes: #79569Fixes: #79566Fixes: #79565
For the first issue (#79569), I got hit a `debug_assert!()` before
encountering the reported error message (because I have `debug = true`
enabled in my config.toml).
The assertion showed me that some `SwitchInt`s can have more than one
target pointing to the same `BasicBlock`.
I had thought that was invalid, but since it seems to be possible, I'm
allowing this now.
I added a new test for this.
----
In the last two cases above, both tests (intentionally) fail to compile,
but the `InstrumentCoverage` pass is invoked anyway.
The MIR starts with an `Unreachable` `BasicBlock`, which I hadn't
encountered before. (I had assumed the `InstrumentCoverage` pass
would only be invoked with MIRs from successful compilations.)
I don't have test infrastructure set up to test coverage on files that
fail to compile, so I didn't add a new test.
Capture precise paths in THIR and MIR
This PR allows THIR and MIR to use the result of the new capture analysis to actually capture precise paths
To achieve we:
- Writeback min capture results to TypeckResults
- Move handling upvars to PlaceBuilder in mir_build
- Lower precise paths in THIR build by reading min_captures
- Search for ancestors in min_capture when trying to build a MIR place which starts off of an upvar
Closes: https://github.com/rust-lang/project-rfc-2229/issues/10
Partly implements: rust-lang/project-rfc-2229#18
Work that remains (not in this PR):
- [ ] [Known bugs when feature gate is enabled](https://github.com/rust-lang/project-rfc-2229/projects/1?card_filter_query=label%3Abug)
- [ ] Use min_capure_map for
- [ ] Liveness analysis
- [ ] rustc_mir/interpret/validity.rs
- [ ] regionck
- [ ] rust-lang/project-rfc-2229#8
- [ ] remove closure_captures and upvar_capture_map
r? `@ghost`
CTFE: tweak abort-on-uninhabited message
Having an "aborted execution:" makes it more consistent with the `Abort` terminator saying "the program aborted execution". Right now, at least one of the two errors will look weird in Miri.
r? `@oli-obk`
Dogfood `str_split_once()`
Part of https://github.com/rust-lang/rust/issues/74773.
Beyond increased clarity, this fixes some instances of a common confusion with how `splitn(2)` behaves: the first element will always be `Some()`, regardless of the delimiter, and even if the value is empty.
Given this code:
```rust
fn main() {
let val = "...";
let mut iter = val.splitn(2, '=');
println!("Input: {:?}, first: {:?}, second: {:?}", val, iter.next(), iter.next());
}
```
We get:
```
Input: "no_delimiter", first: Some("no_delimiter"), second: None
Input: "k=v", first: Some("k"), second: Some("v")
Input: "=", first: Some(""), second: Some("")
```
Using `str_split_once()` makes more clear what happens when the delimiter is not found.
Constier maybe uninit
I was playing around trying to make `[T; N]::zip()` in #79451 be `const fn`. One of the things I bumped into was `MaybeUninit::assume_init`. Is there any reason for the intrinsic `assert_inhabited<T>()` and therefore `MaybeUninit::assume_init` not being `const`?
---
I have as best as I could tried to follow the instruction in [library/core/src/intrinsics.rs](https://github.com/rust-lang/rust/blob/master/library/core/src/intrinsics.rs#L11). I have no idea what I am doing but it seems to compile after some slight changes after the copy paste. Is this anywhere near how this should be done?
Also any ideas for name of the feature gate? I guess `const_maybe_assume_init` is quite misleading since I have added some more methods. Should I add test? If so what should be tested?
Fixes to Rust coverage
Fixes: #79725
Some macros can create a situation where `fn_sig_span` and `body_span`
map to different files.
New documentation on coverage tests incorrectly assumed multiple test
binaries could just be listed at the end of the `llvm-cov` command,
but it turns out each binary needs a `--object` prefix.
This PR fixes the bug and updates the documentation to correct that
issue. It also fixes a few other minor issues in internal implementation
comments, and adds documentation on getting coverage results for doc
tests.
minor stylistic clippy cleanups
simplify if let Some(_) = x to if x.is_some() (clippy::redundant_pattern_matching)
don't create owned values for comparison (clippy::cmp_owned)
use .contains() or .any() instead of find(x).is_some() (clippy::search_is_some)
don't wrap code block in Ok() (clipppy::unit_arg)
Also generate `StorageDead` in constants
r? `@eddyb`
None of this special casing is actually necessary since we started promoting within constants and statics.
We may want to keep some of it around out of perf reasons, but it's not required for user visible behaviour
somewhat related: #68622
remove this weird special case from promotion
Promotion has a special case to ignore interior mutability under some specific circumstances. The purpose of this PR is to figure out what changes if we remove that. Since `Cell::new` and friends only get promoted inside `const`/`static` initializers these days, it actually is not easy to exploit this case: you need something like
```rust
const TEST_INTERIOR_MUT: () = {
// The "0." case is already ruled out by not permitting any interior mutability in `const`.
let _val: &'static _ = &(Cell::new(1), 2).1;
};
```
I assume something like `&Some(&(Cell::new(1), 2).1)` would hit the nested case inside `validate_rvalue`... though I am not sure why that would not just trigger nested promotion, first promoting the inner reference and then the outer one?
Fixes https://github.com/rust-lang/rust/issues/67534 (by simply rejecting that code^^)
r? `@oli-obk` (but for now this is not meant to be merged!)
Cc `@rust-lang/wg-const-eval`
Fixes: #79725
Some macros can create a situation where `fn_sig_span` and `body_span`
map to different files.
New documentation on coverage tests incorrectly assumed multiple test
binaries could just be listed at the end of the `llvm-cov` command,
but it turns out each binary needs a `--object` prefix.
This PR fixes the bug and updates the documentation to correct that
issue. It also fixes a few other minor issues in internal implementation
comments, and adds documentation on getting coverage results for doc
tests.
