Each recursive call was creating an `OsString` for a `&Path`, only for
it to be turned into a `CString` right away. Instead we can directly
pass `.name_cstr()`, saving two allocations each time.
PR #93918 made it so that `-static-libstdc++` was only set in one place,
and was only set during linking, but accidentally also made it so that
it is no longer passed when building LLD or sanitizers, only when
building LLVM itself. This moves the logic for setting
`-static-libstdc++` in the linker flags back to `configure_cmake` so
that it takes effect for all CMake invocations in `native.rs`.
As a side-effect, this also causes libstdc++ to be statically compiled
into sanitizers and LLD if `llvm-tools-enabled` is set but
`llvm-static-stdcpp` is not, even though previously it was only linked
statically if `llvm-static-stdcpp` was set explicitly. But that seems
more like the expected behavior anyway.
This makes the order of the output always consistent:
1. Place of the `match` missing arms
2. The `enum` definition span
3. The structured suggestion to add a fallthrough arm
this also fixes a bug where bootstrap would try to use the fake `rustc` binary built by bootstrap -
cargo puts it in a different directory when using `cargo run` instead of x.py
Same rationale as https://github.com/rust-lang/rust/pull/76544;
it would be nice to make python entirely optional at some point.
This also removes $ROOT as an option for the build directory; I haven't been using it, and like Alex
said in https://github.com/rust-lang/rust/pull/76544#discussion_r488248930 it seems like a
misfeature.
This allows running `cargo run` from src/bootstrap, although that still gives
lots of compile errors if you don't use the beta toolchain.
Add link to closed PR for future optimizers of ChunkedBitSet relations
While optimizing these operations proved unfruitful w.r.t. improving compiler performance right now, faster versions might be needed at a later time. This PR adds a link in the FIXME to save any future optimizers some time, as requested by `@nnethercote` in https://github.com/rust-lang/rust/pull/94625.
r? `@nnethercote`
Rollup of 4 pull requests
Successful merges:
- #93350 (libunwind: readd link attrs to _Unwind_Backtrace)
- #93827 (Stabilize const_fn_fn_ptr_basics, const_fn_trait_bound, and const_impl_trait)
- #94696 (Remove whitespaces and use CSS to align line numbers to the right instead)
- #94700 (rustdoc: Update minifier version)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Rollup of 4 pull requests
Successful merges:
- #93350 (libunwind: readd link attrs to _Unwind_Backtrace)
- #93827 (Stabilize const_fn_fn_ptr_basics, const_fn_trait_bound, and const_impl_trait)
- #94696 (Remove whitespaces and use CSS to align line numbers to the right instead)
- #94700 (rustdoc: Update minifier version)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
rustdoc: Update minifier version
This new version includes a fix for the CSS minifier which was badly handling inline media queries like ``@import` 'i';`.
r? `@notriddle`
Remove whitespaces and use CSS to align line numbers to the right instead
Instead of generating whitespaces to create padding, we simply use the CSS rule: `text-align: right`.
Nice side-effect: it reduces the generated HTML size from **75.004** to **74.828** (MegaBytes) on the std source pages (it's not much but it's always a nice plus 😆 ).
There are no changes in the generated UI.
r? `@notriddle`
Stabilize const_fn_fn_ptr_basics, const_fn_trait_bound, and const_impl_trait
# Stabilization Report
This PR serves as a request for stabilization for three const evaluation features:
1. `const_fn_fn_ptr_basics`
2. `const_fn_trait_bound`
3. `const_impl_trait`
These are being stabilized together because they are relatively minor and related updates to existing functionality.
## `const_fn_fn_ptr_basics`
Allows creating, passing, and casting function pointers in a `const fn`.
The following is an example of what is now allowed:
```rust
const fn get_function() -> fn() {
fn foo() {
println!("Hello, World!");
}
foo
}
```
Casts between function pointer types are allowed, as well as transmuting from integers:
```rust
const fn get_function() -> fn() {
unsafe {
std::mem::transmute(0x1234usize)
}
}
```
However, casting from a function pointer to an integer is not allowed:
```rust
const fn fn_to_usize(f: fn()) -> usize {
f as usize //~ pointers cannot be cast to integers during const eval
}
```
Calling function pointers is also not allowed.
```rust
const fn call_fn_ptr(f: fn()) {
f() //~ function pointers are not allowed in const fn
}
```
### Test Coverage
The following tests include code that exercises this feature:
- `src/test/ui/consts/issue-37550.rs`
- `src/test/ui/consts/issue-46553.rs`
- `src/test/ui/consts/issue-56164.rs`
- `src/test/ui/consts/min_const_fn/allow_const_fn_ptr_run_pass.rs`
- `src/test/ui/consts/min_const_fn/cast_fn.rs`
- `src/test/ui/consts/min_const_fn/cmp_fn_pointers.rs`
## `const_fn_trait_bound`
Allows trait bounds in `const fn`. Additionally, this feature allows creating and passing `dyn Trait` objects.
Examples such as the following are allowed by this feature:
```rust
const fn do_thing<T: Foo>(_x: &T) {
// ...
}
```
Previously only `Sized` was allowed as a trait bound.
There is no way to call methods from the trait because trait methods cannot currently be marked as const. Allowing trait bounds in const functions does allow the const function to use the trait's associated types and constants.
This feature also allowes `dyn Trait` types. These work equivalently to non-const code. Similar to other pointers in const code, the value of a `dyn Trait` pointer cannot be observed.
Note that due to https://github.com/rust-lang/rust/issues/90912, it was already possible to do the example above as follows:
```rust
const fn do_thing<T>(_x: &T) where (T,): Foo {
// ...
}
```
### Test Coverage
The following tests include code that exercises `const_fn_trait_bound`:
- `src/test/ui/consts/const-fn.rs`
- `src/test/ui/consts/issue-88071.rs`
- `src/test/ui/consts/min_const_fn/min_const_fn.rs`
- `src/test/ui/consts/min_const_fn/min_const_fn_dyn.rs`
- `src/test/ui/nll/issue-55825-const-fn.rs`
- Many of the tests in `src/test/ui/rfc-2632-const-trait-impl/` also exercise this feature.
## `const_impl_trait`
Allows argument and return position `impl Trait` in a `const fn`, such as in the following example:
```rust
const fn do_thing(x: impl Foo) -> impl Foo {
x
}
```
Similar to generic parameters and function pointers, this allows the creation of such opaque types, but not doing anything with them beyond accessing associated types and constants.
### Test Coverage
The following tests exercise this feature:
- `src/test/ui/type-alias-impl-trait/issue-53096.rs`
- `src/test/ui/type-alias-impl-trait/issue-53678-generator-and-const-fn.rs`
## Documentation
These features are documented along with the other const evaluation features in the Rust Reference at https://doc.rust-lang.org/stable/reference/const_eval.html.
There is a PR that updates this documentation to reflect the capabilities enabled by these features at https://github.com/rust-lang/reference/pull/1166.
Tracking issues: #57563, #63997, #93706
libunwind: readd link attrs to _Unwind_Backtrace
It seems the removal of these in 1c07096a45 was unintended; readding them fixes the build.
fixesrust-lang/rust#93349
r? `@alexcrichton`
