LuaJIT on Tiger / Leopard / PowerPC!

[cellularmitosis]

Hey folks! Good news, we can now run LuaJIT on Tiger and Leopard / PowerPC!

If you aren't familiar with LuaJIT, it is a just-in-time compiled implementation of Lua, a popular dynamic / "scripting" language.

What makes LuaJIT remarkable is that is one of the if not the fastest JIT implementations ever, and yet it was mostly the work of a single person, Mike Pall, and is mostly hand-crafted assembler. The benchmarks speak for themselves https://luajit.org/performance_ppc.html

Anyway, I was curious if this would run on our old Macs, but ran into compilation errors.

Some googling lead to this post from 9 years ago https://www.freelists.org/post/luajit/LuaJIT-on-PowerPC-Macs which indicated that an older version would compile. So I revived this thread here https://www.freelists.org/post/luajit/LuaJIT-on-OS-X-Leopard-PowerPC,3 and Mike Pall responded with a patch, and now the more recent versions of LuaJIT build and run!

The remaining snag is that FFI (the foreign-function interface, i.e. how you interface with libraries written in C) doesn't work, but I'll dig into this next.

 

[barracuda156]

Hey folks! Good news, we can now run LuaJIT on Tiger and Leopard / PowerPC!

If you aren't familiar with LuaJIT, it is a just-in-time compiled implementation of Lua, a popular dynamic / "scripting" language.

What makes LuaJIT remarkable is that is one of the if not the fastest JIT implementations ever, and yet it was mostly the work of a single person, Mike Pall, and is mostly hand-crafted assembler. The benchmarks speak for themselves https://luajit.org/performance_ppc.html

Anyway, I was curious if this would run on our old Macs, but ran into compilation errors.

Some googling lead to this post from 9 years ago https://www.freelists.org/post/luajit/LuaJIT-on-PowerPC-Macs which indicated that an older version would compile. So I revived this thread here https://www.freelists.org/post/luajit/LuaJIT-on-OS-X-Leopard-PowerPC,3 and Mike Pall responded with a patch, and now the more recent versions of LuaJIT build and run!

The remaining snag is that FFI (the foreign-function interface, i.e. how you interface with libraries written in C) doesn't work, but I'll dig into this next.

I rewrote the patch for Macports version, and it has built:

36-85% port -v installed luajit
The following ports are currently installed:
  luajit @2.1.0-beta3_5 (active) requested_variants='' platform='darwin 10' archs='ppc' date='2022-03-20T01:10:50+0800'

Will it be implemented upstream in the source? If not, I will open a ticket on Macports so that it can be implemented as a patch.

 

[cellularmitosis]

@barracuda156 also, the patch is slightly different for the 2.1.0-beta3 version:

$ cat /tmp/no-plt-2.patch
diff -urN LuaJIT-2.1.0-beta3/src/host/buildvm.c LuaJIT-2.1.0-beta3.patched/src/host/buildvm.c
--- LuaJIT-2.1.0-beta3/src/host/buildvm.c    2017-05-01 14:05:00.000000000 -0500
+++ LuaJIT-2.1.0-beta3.patched/src/host/buildvm.c    2022-03-19 00:45:57.000000000 -0500
@@ -113,7 +113,7 @@
       name[0] = name[1] == 'R' ? '_' : '@';  /* Just for _RtlUnwind@16. */
     else
       *p = '\0';
-#elif LJ_TARGET_PPC && !LJ_TARGET_CONSOLE
+#elif LJ_TARGET_PPC && !LJ_TARGET_CONSOLE && !LJ_TARGET_OSX
     /* Keep @plt etc. */
 #else
     *p = '\0';

 

[cellularmitosis]

@barracuda156 also, the patch is slightly different for the 2.1.0-beta3 version:

$ cat /tmp/no-plt-2.patch
diff -urN LuaJIT-2.1.0-beta3/src/host/buildvm.c LuaJIT-2.1.0-beta3.patched/src/host/buildvm.c
--- LuaJIT-2.1.0-beta3/src/host/buildvm.c    2017-05-01 14:05:00.000000000 -0500
+++ LuaJIT-2.1.0-beta3.patched/src/host/buildvm.c    2022-03-19 00:45:57.000000000 -0500
@@ -113,7 +113,7 @@
       name[0] = name[1] == 'R' ? '_' : '@';  /* Just for _RtlUnwind@16. */
     else
       *p = '\0';
-#elif LJ_TARGET_PPC && !LJ_TARGET_CONSOLE
+#elif LJ_TARGET_PPC && !LJ_TARGET_CONSOLE && !LJ_TARGET_OSX
     /* Keep @plt etc. */
 #else
     *p = '\0';

either way, it just boils down to appending "&& !LJ_TARGET_OSX"

 

[barracuda156]

@barracuda156 also, the patch is slightly different for the 2.1.0-beta3 version:

$ cat /tmp/no-plt-2.patch
diff -urN LuaJIT-2.1.0-beta3/src/host/buildvm.c LuaJIT-2.1.0-beta3.patched/src/host/buildvm.c
--- LuaJIT-2.1.0-beta3/src/host/buildvm.c    2017-05-01 14:05:00.000000000 -0500
+++ LuaJIT-2.1.0-beta3.patched/src/host/buildvm.c    2022-03-19 00:45:57.000000000 -0500
@@ -113,7 +113,7 @@
       name[0] = name[1] == 'R' ? '_' : '@';  /* Just for _RtlUnwind@16. */
     else
       *p = '\0';
-#elif LJ_TARGET_PPC && !LJ_TARGET_CONSOLE
+#elif LJ_TARGET_PPC && !LJ_TARGET_CONSOLE && !LJ_TARGET_OSX
     /* Keep @plt etc. */
 #else
     *p = '\0';

Yes, I already did that, otherwise it won't build.

P. S. Do you know if support for ppc64 may be added? As of now, it fails.

 

[barracuda156]

Fixed now in Macports: https://trac.macports.org/ticket/64853

 

[cellularmitosis]

awesome!

 

[barracuda156]

awesome!

By the way, I just fixed MoarVM, nqp and rakudo (perl6): https://trac.macports.org/ticket/64587

 

[barracuda156]

awesome!

Unfortunately, test performance is miserable though: https://github.com/macports/macports-ports/pull/16651#issuecomment-1315823817