[PROPOSAL] Replace gcov and kcov with llvm-cov

[Chuck Wolber]

Stemming from some hallway track conversations with maintainers at LPC
2026, I propose replacing gcov and kcov in the kernel with llvm-cov.

llvm-cov instruments at the AST which enables precise mapping back to
source code regardless of optimization level.

We have a set of patches [1] that implements kernel based llvm-cov. They
need to be updated and some additional patches are required to address
some stubs that are missing noinstr annotation. But otherwise I should
be able to send a full set of patches (including taking on the
maintainer role) to remove gcov and kcov and replace it with llvm-cov in
fairly short order.

If there is a desire to take this in pieces or implement other
intermediate steps, let me know. Otherwise I can generate a monolithic
set all at once.

[1] https://lore.kernel.org/lkml/20240905043245.1389509-1-wentaoz5@xxxxxxxxxxxx/

Thank you,

..Ch:W..