[LLVMdev] llvm and flushing instruction cache

[Jeffrey Yasskin]

On Sat, Mar 6, 2010 at 10:34 PM, Shasank Chavan
<shanko_chavano at hotmail.com> wrote:
> Hi.  I have a very quick question.  Is the instruction cache flushed by the
> llvm jit before code in memory is written to or executed?  I'm assuming so,
> but I can't find where in the source code this is happening.  In particular
> I searched for clflush, invd, and wbinvd instructions, but couldn't find
> them.  And if it's not necessary to do this, can you please explain why?
> (I'm assuming the target platform has a separate L1 i-cache).  Thanks.

In general, yes. It's possible there are cases we've missed (I fixed
one in the last couple months), in which case please let us know. The
actual code is in sys::Memory::InvalidateInstructionCache
(http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/System/Memory.cpp?view=markup),
called by, for example,
lib/Target/PowerPC/PPCJITInfo.cpp:PPCCompilationCallbackC().