The refactoring mainly keeps the separation between the modules clearer.
For example, process_deferred_edges function moved to cfg_build.rs since
that is really part of building the CFG, not finding the fixpoint.
Also, we use PostOrderId instead of usize in a lot more places now.
Splits drop_ranges into drop_ranges::record_consumed_borrow,
drop_ranges::cfg_build, and drop_ranges::cfg_propagate. The top level
drop_ranges module has an entry point that does all the coordination of
the other three phases, using code original in generator_interior.
All tests pass now! The issue was that we weren't handling all edges
correctly, but now they are handled consistently.
This includes code to dump a graphviz file for the CFG we built for drop
tracking.
Also removes old DropRanges tests.
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
Delete pretty printer tracing
These are left over from 2011. I did not find these helpful at all in my work on https://github.com/dtolnay/prettyplease despite doing significant refactors to this code. Learning what these messages all refer to is harder than putting in your own messages to log exactly what is relevant to specifically the thing that you are working on debugging.
Directly use ConstValue for single literals in blocks
Addresses the minimal repro in https://github.com/rust-lang/rust/issues/92186, but doesn't fix the underlying problem (which would be solved by solving the anon subst problem afaict).
I do, however, think that it makes sense in general to treat single literals in anon blocks as const values directly, especially in light of the problem that the issue refers to (anon const evaluation being postponed until infer variables in substs can be resolved, which was introduced by https://github.com/rust-lang/rust/pull/90023), i.e. while we do get warnings for those unnecessary braces, we should try to avoid errors caused by those braces if possible.
Improve SIMD casts
* Allows `simd_cast` intrinsic to take `usize` and `isize`
* Adds `simd_as` intrinsic, which is the same as `simd_cast` except for saturating float-to-int conversions (matching the behavior of `as`).
cc `@workingjubilee`
Let qpath contain NtTy: `<$:ty as $:ty>::…`
Example:
```rust
macro_rules! m {
(<$type:ty as $trait:ty>::$name:ident) => {
<$type as $trait>::$name
};
}
fn main() {
let _: m!(<str as ToOwned>::Owned);
}
```
Previous behavior:
```console
error: expected identifier, found `ToOwned`
--> src/main.rs:3:19
|
3 | <$type as $trait>::$name
| ^^^^^^ expected identifier
...
8 | let _: m!(<str as ToOwned>::Owned);
| ---------------------------
| |
| this macro call doesn't expand to a type
| in this macro invocation
```
The <code>expected identifier, found \`ToOwned\`</code> error is particularly silly. I think it should be fine to accept this code as long as $trait is of the form `TyKind::Path(None, path)`; if it is any other kind of `NtTy`, we'll keep the same behavior as before.
Implement raw-dylib support for windows-gnu
Add support for `#[link(kind = "raw-dylib")]` on windows-gnu targets. Work around binutils's linker's inability to read import libraries produced by LLVM by calling out to the binutils `dlltool` utility to create an import library from a temporary .DEF file; this approach is effectively a slightly refined version of `@mati865's` earlier attempt at this strategy in PR #88801. (In particular, this attempt at this strategy adds support for `#[link_ordinal(...)]` as well.)
In support of #58713.
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.
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.
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.
