rust/compiler/rustc_codegen_llvm
Matthias Krüger accf61dd42
Rollup merge of #143293 - folkertdev:naked-function-kcfi, r=compiler-errors
fix `-Zsanitizer=kcfi` on `#[naked]` functions

fixes https://github.com/rust-lang/rust/issues/143266

With `-Zsanitizer=kcfi`, indirect calls happen via generated intermediate shim that forwards the call. The generated shim preserves the attributes of the original, including `#[unsafe(naked)]`. The shim is not a naked function though, and violates its invariants (like having a body that consists of a single `naked_asm!` call).

My fix here is to match on the `InstanceKind`, and only use `codegen_naked_asm` when the instance is not a `ReifyShim`. That does beg the question whether there are other `InstanceKind`s that could come up. As far as I can tell the answer is no: calling via `dyn` seems to work find, and `#[track_caller]` is disallowed in combination with `#[naked]`.

r? codegen
````@rustbot```` label +A-naked
cc ````@maurer```` ````@rcvalle````
2025-07-18 04:27:51 +02:00
..

The codegen crate contains the code to convert from MIR into LLVM IR, and then from LLVM IR into machine code. In general it contains code that runs towards the end of the compilation process.

For more information about how codegen works, see the rustc dev guide.