[llvm-commits] [PATCH] review for fix of profiling test failures on ARM

[David Tweed]

Hi Takumi,

Thanks for looking over the patch.

| Some targets don't support MCJIT. Please consider Win32 PECOFF.
| (3 of them don't work on Win32 due to atexit issue, though)

Fair enough: I clearly didn't research the MCJIT status deeply enough. Out
of curiousity, do the profiling tests pass on those platforms as it stands?
(I can't find any of those platforms listed on the buildbot page.)

| What would happen if -use-mcjit were set by default for arm-elf?

That's a good question, one I don't know the complete answer to yet. In
general the old JIT doesn't compile runnable code on ARM and the MCJIT does,
but I don't know if there are any cases where the reverse is true. My
current focus is looking at the regression test failures as reported by the
buildbots and seeing how many can be "properly" resolved so they pass and we
get closer to a more useful default green build on ARM. I'm happy to turn on
mcjit for ARM Elf in some regression tests that are really testing the
profiling instruction insertion, but I'd need to do some more comprehensive
testing before I was happy turning it on for users by default.

Supposing I was to figure out some magic way to add the -use-mcjit option
for those tests only on ARM-Linux, would that be a valid way to fix the
issue in the main tree?

Many thanks,
David Tweed