Use `&raw` in the standard library
Since the stabilization in #127679 has reached stage0, 1.82-beta, we can
start using `&raw` freely, and even the soft-deprecated `ptr::addr_of!`
and `ptr::addr_of_mut!` can stop allowing the unstable feature.
I intentionally did not change any documentation or tests, but the rest
of those macro uses are all now using `&raw const` or `&raw mut` in the
standard library.
bump rustc-build-sysroot version
This removes an implicit `--cap-lints` in the sysroot build. Let's see if that causes any trouble for the targets we test.
Reorder stack spills so that constants come later.
Currently constants are "pulled forward" and have their stack spills emitted first. This confuses LLVM as to where to place breakpoints at function entry, and results in argument values being wrong in the debugger. It's straightforward to avoid emitting the stack spills for constants until arguments/etc have been introduced in debug_introduce_locals, so do that.
Example LLVM IR (irrelevant IR elided):
Before:
```
define internal void `@_ZN11rust_1289457binding17h2c78f956ba4bd2c3E(i64` %a, i64 %b, double %c) unnamed_addr #0 !dbg !178 { start:
%c.dbg.spill = alloca [8 x i8], align 8
%b.dbg.spill = alloca [8 x i8], align 8
%a.dbg.spill = alloca [8 x i8], align 8
%x.dbg.spill = alloca [4 x i8], align 4
store i32 0, ptr %x.dbg.spill, align 4, !dbg !192 ; LLVM places breakpoint here.
#dbg_declare(ptr %x.dbg.spill, !190, !DIExpression(), !192)
store i64 %a, ptr %a.dbg.spill, align 8
#dbg_declare(ptr %a.dbg.spill, !187, !DIExpression(), !193)
store i64 %b, ptr %b.dbg.spill, align 8
#dbg_declare(ptr %b.dbg.spill, !188, !DIExpression(), !194)
store double %c, ptr %c.dbg.spill, align 8
#dbg_declare(ptr %c.dbg.spill, !189, !DIExpression(), !195)
ret void, !dbg !196
}
```
After:
```
define internal void `@_ZN11rust_1289457binding17h2c78f956ba4bd2c3E(i64` %a, i64 %b, double %c) unnamed_addr #0 !dbg !178 { start:
%x.dbg.spill = alloca [4 x i8], align 4
%c.dbg.spill = alloca [8 x i8], align 8
%b.dbg.spill = alloca [8 x i8], align 8
%a.dbg.spill = alloca [8 x i8], align 8
store i64 %a, ptr %a.dbg.spill, align 8
#dbg_declare(ptr %a.dbg.spill, !187, !DIExpression(), !192)
store i64 %b, ptr %b.dbg.spill, align 8
#dbg_declare(ptr %b.dbg.spill, !188, !DIExpression(), !193)
store double %c, ptr %c.dbg.spill, align 8
#dbg_declare(ptr %c.dbg.spill, !189, !DIExpression(), !194)
store i32 0, ptr %x.dbg.spill, align 4, !dbg !195 ; LLVM places breakpoint here.
#dbg_declare(ptr %x.dbg.spill, !190, !DIExpression(), !195)
ret void, !dbg !196
}
```
Note in particular the position of the "LLVM places breakpoint here" comment relative to the stack spills for the function arguments. LLVM assumes that the first instruction with with a debug location is the end of the prologue. As LLVM does not currently offer front ends any direct control over the placement of the prologue end reordering the IR is the only mechanism available to fix argument values at function entry in the presence of MIR optimizations like SingleUseConsts. Fixes#128945
r? `@michaelwoerister`
Since the stabilization in #127679 has reached stage0, 1.82-beta, we can
start using `&raw` freely, and even the soft-deprecated `ptr::addr_of!`
and `ptr::addr_of_mut!` can stop allowing the unstable feature.
I intentionally did not change any documentation or tests, but the rest
of those macro uses are all now using `&raw const` or `&raw mut` in the
standard library.
Don't keep the `external_traits` as shared mutable data between the
`DocContext` and `clean::Crate`. Instead, move the data over when necessary.
This allows us to get rid of a borrowck hack in the `DocVisitor`.
Collect relevant item bounds from trait clauses for nested rigid projections
Rust currently considers trait where-clauses that bound the trait's *own* associated types to act like an item bound:
```rust
trait Foo where Self::Assoc: Bar { type Assoc; }
// acts as if:
trait Foo { type Assoc: Bar; }
```
### Background
This behavior has existed since essentially forever (i.e. before Rust 1.0), since we originally started out by literally looking at the where clauses written on the trait when assembling `SelectionCandidate::ProjectionCandidate` for projections. However, looking at the predicates of the associated type themselves was not sound, since it was unclear which predicates were *assumed* and which predicates were *implied*, and therefore this was reworked in #72788 (which added a query for the predicates we consider for `ProjectionCandidate`s), and then finally item bounds and predicates were split in #73905.
### Problem 1: GATs don't uplift bounds correctly
All the while, we've still had logic to uplift associated type bounds from a trait's where clauses. However, with the introduction of GATs, this logic was never really generalized correctly for them, since we were using simple equality to test if the self type of a trait where clause is a projection. This leads to shortcomings, such as:
```rust
trait Foo
where
for<'a> Self::Gat<'a>: Debug,
{
type Gat<'a>;
}
fn test<T: Foo>(x: T::Gat<'static>) {
//~^ ERROR `<T as Foo>::Gat<'a>` doesn't implement `Debug`
println!("{:?}", x);
}
```
### Problem 2: Nested associated type bounds are not uplifted
We also don't attempt to uplift bounds on nested associated types, something that we couldn't really support until #120584. This can be demonstrated best with an example:
```rust
trait A
where Self::Assoc: B,
where <Self::Assoc as B>::Assoc2: C,
{
type Assoc; // <~ The compiler *should* treat this like it has an item bound `B<Assoc2: C>`.
}
trait B { type Assoc2; }
trait C {}
fn is_c<T: C>() {}
fn test<T: A>() {
is_c::<<Self::Assoc as B>::Assoc2>();
//~^ ERROR the trait bound `<<T as A>::Assoc as B>::Assoc2: C` is not satisfied
}
```
Why does this matter?
Well, generalizing this behavior bridges a gap between the associated type bounds (ATB) feature and trait where clauses. Currently, all bounds that can be stably written on associated types can also be expressed as where clauses on traits; however, with the stabilization of ATB, there are now bounds that can't be desugared in the same way. This fixes that.
## How does this PR fix things?
First, when scraping item bounds from the trait's where clauses, given a trait predicate, we'll loop of the self type of the predicate as long as it's a projection. If we find a projection whose trait ref matches, we'll uplift the bound. This allows us to uplift, for example `<Self as Trait>::Assoc: Bound` (pre-existing), but also `<<Self as Trait>::Assoc as Iterator>::Item: Bound` (new).
If that projection is a GAT, we will check if all of the GAT's *own* args are all unique late-bound vars. We then map the late-bound vars to early-bound vars from the GAT -- this allows us to uplift `for<'a, 'b> Self::Assoc<'a, 'b>: Trait` into an item bound, but we will leave `for<'a> Self::Assoc<'a, 'a>: Trait` and `Self::Assoc<'static, 'static>: Trait` alone.
### Okay, but does this *really* matter?
I consider this to be an improvement of the status quo because it makes GATs a bit less magical, and makes rigid projections a bit more expressive.
Rollup of 6 pull requests
Successful merges:
- #130735 (Simple validation for unsize coercion in MIR validation)
- #130781 (Fix up setting strip = true in Cargo.toml makes build scripts fail in…)
- #130811 (add link from random() helper fn to extensive DefaultRandomSource docs)
- #130819 (Add `must_use` attribute to `len_utf8` and `len_utf16`.)
- #130832 (fix some cfg logic around optimize_for_size and 16-bit targets)
- #130842 (Add tracking issue for io_error_inprogress)
r? `@ghost`
`@rustbot` modify labels: rollup
fix some cfg logic around optimize_for_size and 16-bit targets
Fixes https://github.com/rust-lang/rust/issues/130818.
Fixes https://github.com/rust-lang/rust/issues/129910.
There are still some warnings when building on a 16bit target:
```
warning: struct `AlignedStorage` is never constructed
--> /home/r/src/rust/rustc.2/library/core/src/slice/sort/stable/mod.rs:135:8
|
135 | struct AlignedStorage<T, const N: usize> {
| ^^^^^^^^^^^^^^
|
= note: `#[warn(dead_code)]` on by default
warning: associated items `new` and `as_uninit_slice_mut` are never used
--> /home/r/src/rust/rustc.2/library/core/src/slice/sort/stable/mod.rs:141:8
|
140 | impl<T, const N: usize> AlignedStorage<T, N> {
| -------------------------------------------- associated items in this implementation
141 | fn new() -> Self {
| ^^^
...
145 | fn as_uninit_slice_mut(&mut self) -> &mut [MaybeUninit<T>] {
| ^^^^^^^^^^^^^^^^^^^
warning: function `quicksort` is never used
--> /home/r/src/rust/rustc.2/library/core/src/slice/sort/unstable/quicksort.rs:19:15
|
19 | pub(crate) fn quicksort<'a, T, F>(
| ^^^^^^^^^
warning: `core` (lib) generated 3 warnings
```
However, the cfg stuff here is sufficiently messy that I didn't want to touch more of it. I think all `feature = "optimize_for_size"` should become `any(feature = "optimize_for_size", target_pointer_width = "16")` but I am not entirely certain. Warnings are fine, Miri will just ignore them.
Cc `@Voultapher`
Add `must_use` attribute to `len_utf8` and `len_utf16`.
The `len_utf8` and `len_utf16` methods in `char` should have the `must_use` attribute.
The somewhat similar method `<[T]>::len` has had this attribute since #95274. Considering that these two methods would most likely be used to test the size of a buffer (before a call to `encode_utf8` or `encode_utf16`), *not* using their return values could indicate a bug.
According to ["When to add `#[must_use]`](https://std-dev-guide.rust-lang.org/policy/must-use.html), this is **not** considered a breaking change (and could be reverted again at a later time).
Fix up setting strip = true in Cargo.toml makes build scripts fail in…
Fix issue: https://github.com/rust-lang/rust/issues/110536
Strip binary is PATH dependent which breaks builds in MacOS.
For example, on my Mac, the output of 'which strip' is '/opt/homebrew/opt/binutils/bin/strip', which leads to incorrect 'strip' results. Therefore, just like on other systems, it is also necessary to specify 'stripcmd' on macOS. However, it seems that there is a bug in binutils [bugzilla-Bug 31571](https://sourceware.org/bugzilla/show_bug.cgi?id=31571), which leads to the problem mentioned above.
Simple validation for unsize coercion in MIR validation
This adds the most basic validity check to unsize coercions in MIR. The src and target of an unsize cast must *at least* implement `Src: CoerceUnsized<Target>` for this to be valid.
This doesn't the second, more subtle validity check that is taken of advantage in codegen [here](914193c8f4/compiler/rustc_codegen_ssa/src/base.rs (L126)), but I did leave a beefy FIXME for that explaining what it is.
As a consequence, this also fixes an ICE with GVN and invalid unsize coercions. This is somewhat coincidental, since MIR inlining will check that a body is valid before inlining it; so now that we determine it to be invalid, we don't inline it, and we don't encounter the GVN ICE. I'm not certain if the same GVN ICE is triggerable without the inliner, and perhaps instead with trivial where clauses or something.
cc `@RalfJung`
switch custom target JSON test to a less exotic target
We used to test an AVR target here, but while it is nice to test a 16bit target, it is also currently the case that rustc CI does not even check that libcore builds on a 16bit target -- and we don't want Miri to be in the game of maintaining that support. (See https://github.com/rust-lang/rust/issues/130818.)
So let's use a tier 2 target as the basis for testing a custom JSON target.
(FWIW, we also test wasm32-wasip2 which is tier 3, but I expect it will become tier 2 Soon-ish.)
Android: Fixed tests for libc time API
Closes#3888.
There's nothing to do, really. All of the API is already supported by `miri`, but I just tweaked tests a bit to match the data structures and functions from `bionic`.
