instruction cache flushing in Cygwin

[Glenn Strauss]

On Thu, Jun 05, 2025 at 11:33:18PM -0700, Jeremy Drake via Cygwin wrote:
> I noticed while looking at JIT test failures in LLVM that they don't have
> an implementation for Cygwin for flushing the instruction cache.  I don't
> see any Cygwin function calling FlushInstructionCache, is there some
> POSIXy function for this?  I don't really want to have to include Windows
> headers just to get FlushInstructionCache and GetCurrentProcess, risking
> pulling in a lot of extra definitions.

Do you need something specific to Cygwin, or something that is specific
to CPU-architecture?  GCC and Clang both have __builtin___clear_cache()
intrinsic (yes, with all those underscores)

Cheers, Glenn