Make `#[used]` work when linking with `ld64`
To make `#[used]` work in static libraries, we use the `symbols.o` trick introduced in https://github.com/rust-lang/rust/pull/95604.
However, the linker shipped with Xcode, ld64, works a bit differently from other linkers; in particular, [it completely ignores undefined symbols by themselves](https://github.com/apple-oss-distributions/ld64/blob/ld64-954.16/src/ld/parsers/macho_relocatable_file.cpp#L2455-L2468), and only consider them if they have relocations (something something atoms something fixups, I don't know the details).
So to make the `symbols.o` file work on ld64, we need to actually insert a relocation. That's kinda cumbersome to do though, since the relocation must be valid, and hence must point to a valid piece of machine code, and is hence very architecture-specific.
Fixes https://github.com/rust-lang/rust/issues/133491, see that for investigation.
---
Another option would be to pass `-u _foo` to the final linker invocation. This has the problem that `-u` causes the linker to not be able to dead-strip the symbol, which is undesirable. (If we did this, we would possibly also want to do it by putting the arguments in a file by itself, and passing that file via ``@`,` e.g. ``@undefined_symbols.txt`,` similar to https://github.com/rust-lang/rust/issues/52699, though that [is only supported since Xcode 12](https://developer.apple.com/documentation/xcode-release-notes/xcode-12-release-notes#Linking), and I'm not sure we wanna bump that).
Various other options that are probably all undesirable as they affect link time performance:
- Pass `-all_load` to the linker.
- Pass `-ObjC` to the linker (the Objective-C support in the linker has different code paths that load more of the binary), and instrument the binaries that contain `#[used]` symbols.
- Pass `-force_load` to libraries that contain `#[used]` symbols.
Failed attempt: Embed `-u _foo` in the object file with `LC_LINKER_OPTION`, akin to https://github.com/rust-lang/rust/issues/121293. Doesn't work, both because `ld64` doesn't read that from archive members unless it already has a reason to load the member (which is what this PR is trying to make it do), and because `ld64` only support the `-l`, `-needed-l`, `-framework` and `-needed_framework` flags in there.
---
TODO:
- [x] Support all Apple architectures.
- [x] Ensure that this works regardless of the actual type of the symbol.
- [x] Write up more docs.
- [x] Wire up a few proper tests.
`@rustbot` label O-apple
librustdoc: Use `pulldown-cmark-escape` for HTML escaping
Implementation of `@notriddle` 's [suggestion](https://github.com/rust-lang/rust/pull/137274#issuecomment-2669001585).
Somewhat related to #137274 , but the two PRs should be complementary.
Local perf results look like a nice improvement! (so would love a perf run on the CI)
Emit getelementptr inbounds nuw for pointer::add()
Lower pointer::add (via intrinsic::offset with unsigned offset) to getelementptr inbounds nuw on LLVM versions that support it. This lets LLVM make use of the pre-condition that the offset addition does not wrap in an unsigned sense. Together with inbounds, this also implies that the offset is non-negative.
Fixes https://github.com/rust-lang/rust/issues/137217.
vectorcall ABI: require SSE2
According to the official docs at https://learn.microsoft.com/en-us/cpp/cpp/vectorcall, SSE2 is required for this ABI. Add a check that enforces this.
I put this together with the other checks ensuring the target features required for a function are present... however, since the ABI is known pre-monomorphization, it would be possible to do this check earlier, which would have the advantage of checking even in `cargo check`. It would have the disadvantage of spreading this code in yet more places.
The first commit just does a little refactoring of the mono-time ABI check to make it easier to add the new check.
Cc `@workingjubilee`
try-job: dist-i586-gnu-i586-i686-musl
Rollup of 9 pull requests
Successful merges:
- #135354 ([Debuginfo] Add MSVC Synthetic and Summary providers to LLDB)
- #136826 (Replace mem::zeroed with mem::MaybeUninit::uninit for large struct in Unix)
- #137194 (More const {} init in thread_local)
- #137334 (Greatly simplify lifetime captures in edition 2024)
- #137382 (bootstrap: add doc for vendor build step)
- #137423 (Improve a bit HIR pretty printer)
- #137435 (Fix "missing match arm body" suggestion involving `!`)
- #137448 (Fix bugs due to unhandled `ControlFlow` in compiler)
- #137458 (Fix missing self subst when rendering `impl Fn*<T>` with no output type)
r? `@ghost`
`@rustbot` modify labels: rollup
Improve a bit HIR pretty printer
This PR improve (a bit) the HIR pretty printer.
It does so by:
- Not printing elided lifetimes (those are not expressible in surface Rust anyway)
- And by rendering implicit self with the shorthand syntax
I also tried fixing some indentation and other things but gave up for now.
Best reviewed commit by commit.
Replace mem::zeroed with mem::MaybeUninit::uninit for large struct in Unix
As discussion in #136737.
- Replace `mem::zeroed()` with `MaybeUninit::uninit()` for `sockaddr_storage` in `accept()` and `recvfrom()` since these functions fill in the address structure
- Replace `mem::zeroed()` with `MaybeUninit::uninit()` for `pthread_attr_t` in thread-related functions since `pthread_attr_init()` initializes the structure
- Add references to man pages to document this behavior
[Debuginfo] Add MSVC Synthetic and Summary providers to LLDB
Adds handling for `tuple$<>`, `ref$<slice$2<>`, `ref$<str$>` and `enum2$<>`.
Also fixes a bug in MSVC vec/string handling where the script was unable to determine the element's type due to LLDB ignoring template arg debug information
<details>
<summary>Sample code</summary>
```rust
pub enum Number {
One = 57,
Two = 99,
}
#[repr(u8)]
pub enum Container {
First(u32),
Second { val: u64, val2: i8 },
Third,
}
...
let u8_val = b'a';
let float = 42.78000000000001;
let tuple = (u8_val, float);
let str_val = "eef";
let mut string = "freef".to_owned();
let mut_str = string.as_mut_str();
let array: [u8; 4] = [1, 2, 3, 4];
let ref_array = array.as_slice();
let mut array2: [u32; 4] = [1, 2, 3, 4];
let mut_array = array2.as_mut_slice();
let enum_val = Number::One;
let mut enum_val2 = Number::Two;
let sum_val = Container::First(15);
let sum_val_2 = Container::Second { val: 0, val2: 0 };
let sum_val_3 = Container::Third;
let non_zero = NonZeroU128::new(100).unwrap();
let large_discr = NonZeroU128::new(255);
```
</details>
Before:
After:
try-job: aarch64-apple
try-job: x86_64-msvc-1
try-job: i686-msvc-1
try-job: x86_64-mingw-1
try-job: i686-mingw
try-job: aarch64-gnu
stabilize stage management for rustc tools
https://github.com/rust-lang/rust/pull/135990 got out of control due to excessive complexity. This PR aims to achieve the same goal with a simpler approach, likely through multiple smaller PRs. I will keep the other one read-only and open as a reference for future work.
This work stabilizes the staging logic for `ToolRustc` programs, so you no longer need to handle build and target compilers separately in steps. Previously, most tools didn't do this correctly, which was causing the compiler to be built twice (e.g., `x test cargo --stage 1` would compile the stage 2 compiler before, but now it only compiles the stage 1 compiler).
I also tried to document how we should write `ToolRustc` steps as they are quite different and require more attention than other tools.
Next goal is to stabilize how stages are handled for the rustc itself. Currently, `x build --stage 1` builds the stage 1 compiler which is fine, but `x build compiler --stage 1` builds stage 2 compiler.
~~for now, r? ghost~~
Remove `NtVis` and `NtTy`
The next part of #124141. The first actual remove of `Nonterminal` variants. `NtVis` is a simple case that doesn't get much use, but `NtTy` is more complex.
r? `@petrochenkov`
KonaeAkira
许杰友 Jieyou Xu (Joe)
Josh Stone
Jakub Beránek
Tshepang Mbambo
Oli Scherer
Deadbeef
moxian
Boxy
bors
DianQK
jyn
Jacob Pratt