LLVM for m68k completed (but not merged)

[John Paul Adrian Glaubitz <glaubitz@xxxxxxxxxxxxxxxxxxx>]

Hi!


I just received the news that the m68k backend for LLVM has been finished [1].

It has not been merged upstream yet (that will take some time), but it should
be usable now. I'm currently test-building it on Debian/m68k and it would probably
a good idea if more people give it a spin to help finding issues.

One issue I found is that CycleTimer has not been implemented. A quick fix is to
use the definition used by MIPS, i.e.:

diff --git a/llvm/utils/benchmark/src/cycleclock.h b/llvm/utils/benchmark/src/cycleclock.h
index 1b0f09359c9..88b7805faaf 100644
--- a/llvm/utils/benchmark/src/cycleclock.h
+++ b/llvm/utils/benchmark/src/cycleclock.h
@@ -161,7 +161,7 @@ inline BENCHMARK_ALWAYS_INLINE int64_t Now() {
   struct timeval tv;
   gettimeofday(&tv, nullptr);
   return static_cast<int64_t>(tv.tv_sec) * 1000000 + tv.tv_usec;
-#elif defined(__mips__)
+#elif defined(__mips__) || defined(__m68k__)
   // mips apparently only allows rdtsc for superusers, so we fall
   // back to gettimeofday.  It's possible clock_gettime would be better.
   struct timeval tv;

Thanks,
Adrian

> [1] https://github.com/M680x0/M680x0-mono-repo

-- 
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer - glaubitz@xxxxxxxxxx
`. `'   Freie Universitaet Berlin - glaubitz@xxxxxxxxxxxxxxxxxxx
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