clang 3.8.0 based powerpc (32 bit) buildworld runs on a PowerMac!

[Mark Millard]

I now have an SSD that contains:

0) installkernel material from a gcc 4.2.1 based buildkernel

1) installworld material from a clang 3.8.0 based buildworld
   (clang 3.8.0, libc++, etc.)

It boots and seems to be operating fine after booting --in both a G5 and a G4 PowerMac.

Apparently the clang code generation has been updated to not require an explicit -mlongcall. I had to remove those since clang rejects them on command lines. It linked without complaint (and later seems to be running fine). (I've seen llvm review notes mentioning the "medium model" or some phrase like that for powerpc.)

(I've not been able to buildkernel yet for powerpc (non-64) from my amd64 environment: rejected command lines for other issues. Thus the current limitation to buildworld.)



To get to (1) I did the following sort of sequence:
(The first few steps deal with other issues in order to have sufficient context.)


A) Started by installing the latest powerpc (non-64) snapshot.
   ( http://ftp1.freebsd.org/pub/FreeBSD/snapshots/ISO-IMAGES/11.0/FreeBSD-11.0-CURRENT-powerpc-20160113-r293801-disc1.iso )

   (I had to use a PowerMac with video hardware that vt would handle.)
   (Basic display, no X-windows involvement here.)


B) Rebuild, including using my usual kernel configuration that has
   both vt and sc. I did this based on projects/clang380-import
   -r294201 /usr/src but still using gcc 4.2.1 (native on the
   PowerMac). The configuration turns off kernel debugging extras too.


C) installkernel, installworld, etc., set to use sc instead of vt, and rebooted.

   (As of this I could use the SSD in more PowerMacs by using sc instead of vt via a /boot/loader.conf assignment.)


D) dump/restore the file systems to another SSD (after partitioning it).
   Adjust the host name and the like on the copy.

   (This copy later ends up having new installworld materials overlaid.)


E) In a projects/clang380-import -r294201 amd64 environment, buildworld for
   TARGET_ARCH=powerpc . WITH_LIBCPLUSPLUS= and clang related material built,
   gcc 4.2.1 related material not built. WITH_BOOT= as well. I choose
   WITHOUT_DEBUG= and WITHOUT_DEBUG_FILES= . (I've not tried enabling them yet.)
   binutils is not from ports.


F) Use DESTDIR= with installworld to an initially empty directory tree. tar the tree.
   

G) Transfer the tar file to the PowerMac. Mount the to-be-updated SSD to
   /mnt and /mnt/var. After chflags -R noschg on /mnt and /mnt/var use
   tar xpf to replace things from the buildworld on /mnt and /mnt/var.

   (This does leave older gcc 4.2.1 related materials in place.)

H) Dismounts, shutdown, and then boot from the updated SSD.



Note: I've never manage to get powerpc64-xtoolchain-gcc/powerpc64-gcc to produce working 32-bit code. So I've never gotten this far via that path.


===
Mark Millard
markmi at dsl-only.net