Rollup of 6 pull requests
Successful merges:
- rust-lang/rust#143069 (Add fast-path for accessing the current thread id)
- rust-lang/rust#146518 (Improve the documentation around `ZERO_AR_DATE`)
- rust-lang/rust#146596 (Add a dummy codegen backend)
- rust-lang/rust#146617 (Don’t suggest foreign `doc(hidden)` types in "the following other types implement trait" diagnostics)
- rust-lang/rust#146635 (cg_llvm: Stop using `as_c_char_ptr` for coverage-related bindings)
- rust-lang/rust#147184 (Fix the bevy implied bounds hack for the next solver)
r? `@ghost`
`@rustbot` modify labels: rollup
cg_llvm: Stop using `as_c_char_ptr` for coverage-related bindings
[As explained by a note in `ffi.rs`](8a1b39995e/compiler/rustc_codegen_llvm/src/llvm/ffi.rs (L4-L11)), passing strings and byte slices through FFI is more convenient if we take advantage of the fact that `*const c_uchar` and `*const c_char` have the same ABI.
Doing so avoids having to rely on a special helper function, since we can just call `as_ptr` instead.
(The same logic applies to every other binding that currently uses the `as_c_char_ptr` helper; I just haven't adjusted all of them yet.)
---
As a drive-by change, this PR also marks some coverage-related FFI bindings as `safe`.
cg_llvm: Replace some DIBuilder wrappers with LLVM-C API bindings (part 5)
- Part of rust-lang/rust#134001
- Follow-up to rust-lang/rust#146673
---
This is another batch of LLVMDIBuilder binding migrations, replacing some our own LLVMRust bindings with bindings to upstream LLVM-C APIs.
Some of these are a little more complex than most of the previous migrations, because they split one LLVMRust binding into multiple LLVM bindings, but nothing too fancy.
This appears to be the last of the low-hanging fruit. As noted in https://github.com/rust-lang/rust/issues/134001#issuecomment-2524979268, the remaining bindings are difficult or impossible to migrate at present.
cg_llvm: Move target machine command-line quoting from C++ to Rust
When this code was introduced in rust-lang/rust#130446 and rust-lang/rust#131805, it was complicated by the need to maintain compatibility with earlier versions of LLVM.
Now that LLVM 20 is the baseline (rust-lang/rust#145071), we can do all of the quoting in pure Rust code, and pass two flat strings to LLVM to be used as-is.
---
In this PR, my priority has been to preserve the existing behaviour as much as possible, without worrying too much about what the behaviour *should* be. (Though I did avoid a leading space before the first argument.)
cg_llvm: Replace some DIBuilder wrappers with LLVM-C API bindings (part 4)
- Part of rust-lang/rust#134001
- Follow-up to rust-lang/rust#146631
---
This is another batch of LLVMDIBuilder binding migrations, replacing some our own LLVMRust bindings with bindings to upstream LLVM-C APIs.
Make llvm_enzyme a regular cargo feature
This makes it clearer that it is set by the build system rather than by the rustc that compiles the current rustc. It also avoids bootstrap needing to pass `--check-cfg llvm_enzyme` to rustc.
cg_llvm: Replace some DIBuilder wrappers with LLVM-C API bindings (part 3)
- Part of rust-lang/rust#134001
- Follow-up to rust-lang/rust#136375
- Follow-up to rust-lang/rust#136632
---
This is another batch of LLVMDIBuilder binding migrations, replacing some our own LLVMRust bindings with bindings to upstream LLVM-C APIs.
This PR migrates all of the bindings that were touched by rust-lang/rust#136632, plus `LLVMDIBuilderCreateStructType`.
This makes it clearer that it is set by the build system rather than by
the rustc that compiles the current rustc. It also avoids bootstrap
needing to pass --check-cfg llvm_enzyme to rustc.
Use captures(address) instead of captures(none) for indirect args
While provenance cannot be captured through these arguments, the address / object identity can.
Fixes https://github.com/rust-lang/rust/issues/137668.
r? `@ghost`
The underlying implementation of `LLVMCreateConstantRangeAttribute` assumes
that each of `LowerWords` and `UpperWords` points to enough u64 values to
define an integer of the specified bit-length, and will encounter UB if that is
not the case.
Our safe wrapper function always passes pointers to `[u64; 2]` arrays,
regardless of the bit-length specified. That's fine in practice, because scalar
primitives never exceed 128 bits, but it is technically a soundness hole in a
safe function.
We can close the soundness hole by explicitly asserting `size_bits <= 128`.
This is effectively just a stricter version of the existing check that the
value must be small enough to fit in `c_uint`.
`&Freeze` parameters are not only `readonly` within the function,
but any captures of the pointer can also only be used for reads.
This can now be encoded using the `captures(address, read_provenance)`
attribute.
