Re: FYI: Why META_MODE rebuilds so much for building again after installworld (no source changes)

On Feb 23, 2023, at 19:54, Simon J. Gerraty <sjg@juniper.net> wrote:
> 
>> 
>> First some output log lines around a few sbin/realpath "is newer than"
>> related Building lines, with the .info lines in place now (I've
>> got both kmod.mk and kern.mk with the .info line, likely producing
>> redundant output but I did not know up front for sure):
>> 
>> make[4]: "/usr/main-src/sys/conf/kmod.mk" line 72:
>> .CURDIR=/usr/main-src/sys/modules/aac
>> .OBJDIR=/usr/obj/BUILDs/main-amd64-nodbg-clang/usr/main-src/amd64.amd64/sys/GENERIC-NODBG/modules/usr/main-src/sys/modules/aac
>> OBJTOP=/usr/obj/BUILDs/main-amd64-nodbg-clang/usr/main-src/amd64.amd64/sys/GENERIC-NODBG/modules/usr/main-src
> 
> So as you can see that OBJTOP not does provide a match for where
> /usr/obj/BUILDs/main-amd64-nodbg-clang/usr/main-src/amd64.amd64/tmp/legacy/usr/sbin/realpath is
> 
> you really want it fixed at
> 
> /usr/obj/BUILDs/main-amd64-nodbg-clang/usr/main-src/amd64.amd64
> 
> which is difficult given the way it is defined in
> src.sys.obj.mk

Yep, but possibly understated.

> Perhaps you want to be using
> 
> .MAKE.META.IGNORE_PATHS+= ${MAKEOBJDIRPREFIX}/tmp/legacy/usr
> or is that ${MAKEOBJDIRPREFIX}/${TARGET}.${TARGET_ARCH}/tmp/legacy/usr 
> 

I had started with trying to use MAKEOBJDIRPREFIX but it
appeared to end up with an empty expansion in something
I'd looked at, making the addition to
.MAKE.META.IGNORE_PATHS ineffective.

But with the .info lines in place, I should probably
recheck an example with ${MAKEOBJDIRPREFIX} in it.
(Expecting .MAKE.META.IGNORE_PATHS to not work but
showing what happens for the MAKEOBJDIRPREFIX use.)
This turns out to be different for "modules" vs.
"pure kernel". I start with a "modules" example
below.

So for .MAKE.META.IGNORE_PATHS += ${MAKEOBJDIRPREFIX}/tmp/legacy/usr
. . .

make[4]: "/usr/main-src/sys/conf/kmod.mk" line 72: 
.CURDIR=/usr/main-src/sys/modules/aac
.OBJDIR=/usr/obj/BUILDs/main-amd64-nodbg-clang/usr/main-src/amd64.amd64/sys/GENERIC-NODBG/modules/usr/main-src/sys/modules/aac
OBJTOP=/usr/obj/BUILDs/main-amd64-nodbg-clang/usr/main-src/amd64.amd64/sys/GENERIC-NODBG/modules/usr/main-src
.MAKE.META.IGNORE_PATHS=/bin/sh  /bin  /lib  /rescue  /sbin  /usr/bin  /usr/lib  /usr/sbin  /usr/share /usr/include /usr/local/etc/libmap.d /usr/obj/BUILDs/main-amd64-nodbg-clang/usr/main-src/amd64.amd64/sys/GENERIC-NODBG/modules/tmp/legacy/usr
make[4]: "/usr/main-src/sys/conf/kern.mk" line 3:  .CURDIR=/usr/main-src/sys/modules/aac
.OBJDIR=/usr/obj/BUILDs/main-amd64-nodbg-clang/usr/main-src/amd64.amd64/sys/GENERIC-NODBG/modules/usr/main-src/sys/modules/aac
OBJTOP=/usr/obj/BUILDs/main-amd64-nodbg-clang/usr/main-src/amd64.amd64/sys/GENERIC-NODBG/modules/usr/main-src
.MAKE.META.IGNORE_PATHS=/bin/sh  /bin  /lib  /rescue  /sbin  /usr/bin  /usr/lib  /usr/sbin  /usr/share /usr/include /usr/local/etc/libmap.d /usr/obj/BUILDs/main-amd64-nodbg-clang/usr/main-src/amd64.amd64/sys/GENERIC-NODBG/modules/tmp/legacy/usr
/usr/obj/BUILDs/main-amd64-nodbg-clang/usr/main-src/amd64.amd64/sys/GENERIC-NODBG/modules/usr/main-src/sys/modules/aac/machine.meta: 23: file '/usr/obj/BUILDs/main-amd64-nodbg-clang/usr/main-src/amd64.amd64/tmp/legacy/usr/sbin/realpath' is newer than the target...
Building /usr/obj/BUILDs/main-amd64-nodbg-clang/usr/main-src/amd64.amd64/sys/GENERIC-NODBG/modules/usr/main-src/sys/modules/aac/machine

So, it looks like it ended up with MAKEOBJDIRPREFIX being:

/usr/obj/BUILDs/main-amd64-nodbg-clang/usr/main-src/amd64.amd64/sys/GENERIC-NODBG/modules

But looking outside the "modules" part of the kernel build
log ends up showing:

.MAKE.META.IGNORE_PATHS=/bin/sh  /bin  /lib  /rescue  /sbin  /usr/bin  /usr/lib  /usr/sbin  /usr/share /usr/include /usr/local/etc/libmap.d /tmp/legacy/usr

So MAKEOBJDIRPREFIX expanded to empty, resulting in:
/tmp/legacy/usr .

So: more can-not-get-there-from-here. I've still no
clue of a notation that will work. (It would need to
apply to buildworld as well, making for more
constraints than just working for buildkernel.)

As for:

${MAKEOBJDIRPREFIX}/${TARGET}.${TARGET_ARCH}/tmp/legacy/usr

my memory is that ${TARGET}.${TARGET_ARCH} are supposed to
only be use in the top level makefiles. But, just seeing
what results . . .

/usr/obj/BUILDs/main-amd64-nodbg-clang/usr/main-src/amd64.amd64/sys/GENERIC-NODBG/modules/amd64.amd64/tmp/legacy/usr

Still not right for "modules".

I'll note that outside modules, it is:

/amd64.amd64/tmp/legacy/usr

and still not right (MAKEOBJDIRPREFIX expanded
to empty).


I still do not know notation to make .MAKE.META.IGNORE_PATHS
effective for the specific list of tmp/legacy/usr/sbin/*
examples in question.

Effectively, it appears that the coverage of
.MAKE.META.IGNORE_PATHS is just incomplete (via the
notational constraints it is used within).

===
Mark Millard
marklmi at yahoo.com