This adds support for branching and merging control flow and uses this
to correctly handle the case where a value is dropped in one branch of
an if expression but not another.
There are other cases we need to handle, which will come in follow up
patches.
Issue #57478
This is needed to handle cases like `[a, b.await, c]`. `ExprUseVisitor`
considers `a` to be consumed when it is passed to the array, but the
array is not quite live yet at that point. This means we were missing
the `a` value across the await point. Attributing drops to the parent
expression means we do not consider the value consumed until the
consuming expression has finished.
Issue #57478
The main change needed to make this work is to do a pessimistic over-
approximation for AssignOps. The existing ScopeTree analysis in
region.rs works by doing both left to right and right to left order and
then choosing the most conservative ordering. This behavior is needed
because AssignOp's evaluation order depends on whether it is a primitive
type or an overloaded operator, which runs as a method call.
This change mimics the same behavior as region.rs in
generator_interior.rs.
Issue #57478
This change adds the basic infrastructure for tracking drop ranges in
generator interior analysis, which allows us to exclude dropped types
from the generator type.
Not yet complete, but many of the async/await and generator tests pass.
The main missing piece is tracking branching control flow (e.g. around
an `if` expression). The patch does include support, however, for
multiple yields in th e same block.
Issue #57478
Avoid unnecessary monomorphization of inline asm related functions
This should reduce build time for codegen backends by avoiding duplicated monomorphization of certain inline asm related functions for each passed in closure type.
Rollup of 14 pull requests
Successful merges:
- #92629 (Pick themes on settings page, not every page)
- #92640 (Fix ICEs related to `Deref<Target=[T; N]>` on newtypes)
- #92701 (Add some more attribute validation)
- #92803 (Hide mobile sidebar on some clicks)
- #92830 (Rustdoc style cleanups)
- #92866 ("Does exists" typos fix)
- #92870 (add `rustc_diagnostic_item` attribute to `AtomicBool` type)
- #92914 (htmldocck: Add support for `/text()` in ``@snapshot`)`
- #92923 (Abstract the pretty printer's ringbuffer to be infinitely sized)
- #92946 (Exclude llvm-libunwind from the self-contained set on s390x-musl targets)
- #92947 (rustdoc: Use `intersperse` in a `visit_path` function)
- #92997 (Add `~const` bound test for negative impls)
- #93004 (update codegen test for LLVM 14)
- #93016 (Stabilize vec_spare_capacity)
Failed merges:
- #92924 (Delete pretty printer tracing)
r? `@ghost`
`@rustbot` modify labels: rollup
rustdoc: Use `intersperse` in a `visit_path` function
(~~Is there a better way to word the title?~~ Eh, this works, I guess.)
I'm surprised that the compiler didn't complain when I left out the `.to_string()`, but hey, if it works then it works.
Exclude llvm-libunwind from the self-contained set on s390x-musl targets
llvm-libunwind does not support s390x targets at present, so we cannot build it
for s390x targets. Accordingly, remove it from the self-contained set.
Abstract the pretty printer's ringbuffer to be infinitely sized
This PR backports 8e5e83c3ff from the `prettyplease` crate into `rustc_ast_pretty`.
Using a dedicated RingBuffer type with non-wrapping indices, instead of manually `%`-ing indices into a capped sized buffer, unlocks a number of simplifications to the pretty printing algorithm implementation in followup commits such as fcb5968b1e and 4427cedcb8.
This change also greatly reduces memory overhead of the pretty printer. The old implementation always grows its buffer to 205920 bytes even for files without deeply nested code, because it only wraps its indices when they hit the maximum tolerable size of the ring buffer (the size after which the pretty printer will crash if there are that many tokens buffered). In contrast, the new implementation uses memory proportional to the peak number of simultaneously buffered tokens only, not the number of tokens that have ever been in the buffer.
Speaking of crashing the pretty printer and "maximum tolerable size", the constant used for that in the old implementation is a lie:
de9b573eed/compiler/rustc_ast_pretty/src/pp.rs (L227-L228)
It was raised from 3 to 55 in https://github.com/rust-lang/rust/pull/33934 because that was empirically the size that avoided crashing on one particular test crate, but according to https://github.com/rust-lang/rust/pull/33934#issuecomment-226700470 other syntax trees still crash at that size. There is no reason to believe that any particular size is good enough for arbitrary code, and using a large number like 55 adds overhead to inputs that never need close to that much of a buffer. The new implementation eliminates this tradeoff.
htmldocck: Add support for `/text()` in `@snapshot`
This allows just testing the text, in cases where the HTML tags don't
matter.
See https://github.com/rust-lang/rust/pull/92908#discussion_r785191758 for an example of when this would be useful.
r? `@GuillaumeGomez`
add `rustc_diagnostic_item` attribute to `AtomicBool` type
I wanted to use this in clippy and found that it didn't work. So hopefully this addition will fix it.
Rustdoc style cleanups
- Make "since" version numbers grey again (regressed in #92602).
- Remove unneeded selectors for when crate filter dropdown is a
sibling of search-input.
- Crate filter dropdown doesn't need to be 100% width on mobile.
- Only build crate filter dropdown when there is more than one crate.
- Remove unused addCrateDropdown
Demo: https://rustdoc.crud.net/jsha/style-cleanups/std/string/struct.String.html
r? `@GuillaumeGomez`
Add some more attribute validation
This adds some more validation for the position of attributes:
* `link` is only valid on an `extern` block
* `windows_subsystem` and `no_builtins` are only valid at the crate level
Fix ICEs related to `Deref<Target=[T; N]>` on newtypes
1. Stash a const infer's type into the canonical var during canonicalization, so we can recreate the fresh const infer with that same type.
For example, given `[T; _]` we know `_` is a `usize`. If we go from infer => canonical => infer, we shouldn't forget that variable is a usize.
Fixes#92626Fixes#83704
2. Don't stash the autoderef'd slice type that we get from method lookup, but instead recreate it during method confirmation. We need to do this because the type we receive back after picking the method references a type variable that does not exist after probing is done.
Fixes#92637
... A better solution for the second issue would be to actually _properly_ implement `Deref` for `[T; N]` instead of fixing this autoderef hack to stop leaking inference variables. But I actually looked into this, and there are many complications with const impls.
Pick themes on settings page, not every page
This hides the paintbrush icon on most pages by default, in preference for the settings on the settings page. When loading from a local file, and not in mobile view, continue to show the theme picker. That's because some browsers limit access to localStorage from file:/// URLs, so choosing a theme from settings.html doesn't take effect.
Fixes#84539
Part of #59840
r? `@GuillaumeGomez`
Demo: https://rustdoc.crud.net/jsha/theme-picker-local-only-2/std/io/trait.Read.html
Out of cycle Clippy update
I want to do an out-of-cycle sync for rust-lang/rust-clippy#8295, and possibly backport this to stable together with https://github.com/rust-lang/rust/issues/92938. If this doesn't get backported to stable, then I at least want to backport it to beta.
r? `@Manishearth`
Replace use of `ty()` on term and use it in more places. This will allow more flexibility in the
future, but slightly worried it allows items which are consts which only accept types.
- Make "since" version numbers grey again (regressed in #92602).
- Remove unneeded selectors for when crate filter dropdown is a
sibling of search-input.
- Crate filter dropdown doesn't need to be 100% width on mobile.
- Only build crate filter dropdown when there is more than one crate.
- Remove unused addCrateDropdown.
Use `carrying_{mul|add}` in `num::bignum`
Now that we have (unstable) methods for this, we don't need the bespoke trait methods for it in the `bignum` implementation.
cc #85532
Add `log2` and `log10` to `NonZeroU*`
This version is nice in that it doesn't need to worry about zeros, and thus doesn't have any error cases.
cc `int_log` tracking issue #70887
(I didn't add them to `NonZeroI*` despite it being on `i*` since allowing negatives bring back the error cases again.)
Remove LLVMRustMarkAllFunctionsNounwind
This was originally introduced in #10916 as a way to remove all landing
pads when performing LTO. However this is no longer necessary today
since rustc properly marks all functions and call-sites as nounwind
where appropriate.
In fact this is incorrect in the presence of `extern "C-unwind"` which
must create a landing pad when compiled with `-C panic=abort` so that
foreign exceptions are caught and properly turned into aborts.
rustc_codegen_llvm: Remove (almost) unused span parameter from many functions in metadata.rs
Many functions and intermediate data structures in `rustc_codegen_llvm/src/debuginfo/metadata.rs` take a span parameter that is only used for providing a span to a `span_bug!()` invocation, in case the debuginfo typemap gets corrupted. However, this span does not really convey useful information as it just points to the first point a type is used -- and half of the time is initialized to `DUMMY_SP`.
This PR removes this span parameter from the module.
It also removes the following unused parameters from `composite_type_metadata()` together with an outdated comment:
```rust
// Ignore source location information as long as it
// can't be reconstructed for non-local crates.
_file_metadata: &'ll DIFile,
_definition_span: Span,
```
Implement `#[rustc_must_implement_one_of]` attribute
This PR adds a new attribute — `#[rustc_must_implement_one_of]` that allows changing the "minimal complete definition" of a trait. It's similar to GHC's minimal `{-# MINIMAL #-}` pragma, though `#[rustc_must_implement_one_of]` is weaker atm.
Such attribute was long wanted. It can be, for example, used in `Read` trait to make transitions to recently added `read_buf` easier:
```rust
#[rustc_must_implement_one_of(read, read_buf)]
pub trait Read {
fn read(&mut self, buf: &mut [u8]) -> Result<usize> {
let mut buf = ReadBuf::new(buf);
self.read_buf(&mut buf)?;
Ok(buf.filled_len())
}
fn read_buf(&mut self, buf: &mut ReadBuf<'_>) -> Result<()> {
default_read_buf(|b| self.read(b), buf)
}
}
impl Read for Ty0 {}
//^ This will fail to compile even though all `Read` methods have default implementations
// Both of these will compile just fine
impl Read for Ty1 {
fn read(&mut self, buf: &mut [u8]) -> Result<usize> { /* ... */ }
}
impl Read for Ty2 {
fn read_buf(&mut self, buf: &mut ReadBuf<'_>) -> Result<()> { /* ... */ }
}
```
For now, this is implemented as an internal attribute to start experimenting on the design of this feature. In the future we may want to extend it:
- Allow arbitrary requirements like `a | (b & c)`
- Allow multiple requirements like
- ```rust
#[rustc_must_implement_one_of(a, b)]
#[rustc_must_implement_one_of(c, d)]
```
- Make it appear in rustdoc documentation
- Change the syntax?
- Etc
Eventually, we should make an RFC and make this (or rather similar) attribute public.
---
I'm fairly new to compiler development and not at all sure if the implementation makes sense, but at least it passes tests :)
Clarifications in the target tier policy
We've added several targets since the introduction of the target tier policy. Based on experiences of those adding such targets, and discussions around such additions, clarify the target tier policy to make it easier to follow and work with.
None of these changes substantively change the requirements on targets. (In some cases the changes do direct target submitters to follow specific process requirements for the addition of a target, such as how to respond to requirements, where to put target-specific documentation, or what should appear in that documentation. Those changes are procedural in nature and document the procedures we already direct people to follow.)
- Clarify how to quote and respond to the target tier policy requirements. Several times, people have seemed unclear on how to respond to some of the policy requirements, particularly those that just state things the target developers must *not* do (e.g. not posting to PRs that break the target). Add a note that such requirements just need acknowledgement, nothing more.
- Clarify dependency requirements in the face of cross-compilation. I previously phrased this confusingly in terms of "host tools", since that is the case where an exception applies (allowing proprietary target libraries commonly used by binaries for the target). Rephrase it to apply equally to cross-compilation. This doesn't change the net effect of the requirements, since other requirements already cover the dependencies of the Rust toolchain.
- Clarify documentation about running binaries. The requirement for target documentation talks about "running tests", but tier 3 targets often don't support running the full testsuite, and in practice the documentation for how to run an individual binary may be more useful. Change "running tests" to "running binaries, or running tests".
- Explain where to place target-specific documentation (a subdirectory of platform-support, with a link from the platform-support entry for the target).
- Add a template for target-specific documentation.
ProjectionPredicate should be able to handle both associated types and consts so this adds the
first step of that. It mainly just pipes types all the way down, not entirely sure how to handle
consts, but hopefully that'll come with time.
