Overhaul the MACHINE_CPU behaviour:

* Rip out MACHINE_CPU stuff from sys.mk and include a new <bsd.cpu.mk>
  after we pull in /etc/make.conf.  We need to do it afterwards so we can
  react to the user setting of the:

* CPUTYPE variable, which contains the CPU type which the user wants to
  optimize for.  For example, if you want your binaries to only run on an
  i686-class machine (or higher), set this to i686.  If you want to support
  running binaries on a variety of CPU generations, set this to the lowest
  common denominator.  Supported values are listed in make.conf.

* bsd.cpu.mk does the expansion of CPUTYPE into MACHINE_CPU using the
  (hopefully) correct unordered list of CPU types which should be used on
  that CPU.  For example, an AMD k6 CPU wants any of the following:
    k6 k5 i586 i486 i386
  This is still an unordered list so the client makefile logic is simple -
  client makefiles need to test for the various elements of the set in
  decreasing order of priority using ${MACHINE_CPU:M<foo>}, as before.
  The various MACHINE_CPU lists are believed to be correct, but should be
  checked.

* If NO_CPU_CFLAGS is not defined, add relevant gcc compiler optimization
  settings by default (e.g. -karch=k6 for CPUTYPE=k6, etc).  Release
  builders and developers of third-party software need to make sure not to
  enable CPU-specific optimization when generating code intended to be
  portable.  We probably need to move to an /etc/world.conf to allow the
  optimization stuff to be applied separately to world/kernel and external
  compilations, but it's not any worse a problem than it was before.

* Add coverage for the ia64/itanium MACHINE_ARCH/CPUTYPE.

* Add CPUTYPE support for all of the CPU types supported by FreeBSD and gcc
  (only i386, alpha and ia64 first, since those are the minimally-working
  ports.  Other architecture porters, please feel free to add the relevant
  gunk for your platform).

Reviewed by:    jhb, obrien

1 files changed, 14 insertions, 12 deletions

diff --git a/etc/defaults/make.conf b/etc/defaults/make.conf
index f909dfd37081..be729cf3f493 100644
--- a/etc/defaults/make.conf
+++ b/etc/defaults/make.conf
@@ -13,18 +13,20 @@
 # You have to find the things you can put here in the Makefiles and 
 # documentation of the source tree.
 #
-# 
-# MACHINE_CPU controls which processor-specific optimizations will be
-# used by certain components of FreeBSD (currently only OpenSSL).
-# This should be set to a list of your CPU type, plus all previous
-# generations of the CPU architecture.  The reason for using a list is
-# because not all programs which use the MACHINE_CPU variable may have
-# optimizations for your specific CPU generation (e.g. Pentium Pro),
-# but may have optimizations for the previous generation (e.g. Pentium).
-# Currently only the following CPU generations are used:
-# i686 i585 i386
-#
-#MACHINE_CPU=i686 i586 i386
+#
+# The CPUTYPE variable controls which processor should be targetted for
+# generated code.  This controls processor-specific optimizations in
+# certain code (currently only OpenSSL) as well as modifying the value
+# of CFLAGS to contain the appropriate optimization directive to gcc.
+# The automatic setting of CFLAGS may be overridden using the
+# NO_CPU_CFLAGS variable below.
+# Currently the following CPU types are recognised:
+#   Intel x86 architecture: k7 k6 k5 i686 i585 i486 i386
+#   Alpha/AXP architecture: ev6 pca56 ev56 ev5 ev45 ev4
+#   Intel ia64 architecture: itanium
+#
+#CPUTYPE=i686
+#NO_CPU_CFLAGS=	true	# Don't add -march=<cpu> to CFLAGS automatically
 #
 # CFLAGS controls the compiler settings used when compiling C code.
 # Note that optimization settings above -O (-O2, ...) are not recommended