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However, under > `CONFIG_RUST_INLINE_HELPERS=3Dy`, `rustc` emits LLVM bitcode and Clang > performs final code generation after the helper bitcode is linked, > but Clang does not trap unreachable IR by default. >=20 > In turn, this means `objtool` follows compiler-generated impossible Rust > `enum` paths through alignment padding into the next function, resulting > in fallthrough warnings. >=20 > Thus pass the LLVM `trap-unreachable` option to the final Clang invocatio= n > and suppress traps immediately after `noreturn` calls, which `objtool` > already recognizes as dead ends. The combination of both flags makes it > match `rustc`'s behavior. >=20 > Rust 1.85.0 (the minimum supported one) supports LLVM >=3D 18, and both > flags are available in LLVM 18. >=20 > Assisted-by: LLM > Cc: Gary Guo > Cc: Boqun Feng > Cc: Alice Ryhl > Cc: Matthew Maurer > Cc: Josh Poimboeuf > Cc: Peter Zijlstra > Cc: stable@vger.kernel.org > Fixes: 3a2486cc1da5 ("kbuild: rust: provide an option to inline C helpers= into Rust") > Signed-off-by: Miguel Ojeda Acked-by: Gary Guo > --- > Makefile | 10 ++++++++++ > rust/Makefile | 3 ++- > scripts/Makefile.build | 3 ++- > 3 files changed, 14 insertions(+), 2 deletions(-)