freebsd stable - May 2018 - 11.1-RELEASE-p10 cannot compile freebsd stable/11 kernel?

On Sun, May 13, 2018 at 09:58:29AM -0500, Mike Karels
wrote:
> I attempted a kernel compile from stable/11, as a freebsd-update didn't
> seem to update /usr/src/sys, and I'm running a custom kernel.  I get
> compile errors like this:
> 
>     ../../../amd64/amd64/support.S:829:2: error: unknown directive
>      .altmacro
>      ^
>     <instantiation>:1:13: error: invalid register name
>     handle_ibrs_%(ll):
> 		^~
>     <instantiation>:3:2: note: while in macro instantiation
>      ibrs_seq_label %(ll)
>      ^
>     <instantiation>:2:2: note: while in macro instantiation
>      .rept 32
>      ^
>     ../../../amd64/amd64/support.S:858:2: note: while in macro
instantiation
>      ibrs_seq 32
>      ^
>     <instantiation>:1:13: error: invalid register name
>     handle_ibrs_%(ll):
> 		^~
>     <instantiation>:8:2: note: while in macro instantiation
>      ibrs_seq_label %(ll)
>      ^
>     <instantiation>:2:2: note: while in macro instantiation
>      .rept 32
>      ^
>     ../../../amd64/amd64/support.S:858:2: note: while in macro
instantiation
>      ibrs_seq 32
>      ^
>     <instantiation>:1:13: error: invalid register name
>     handle_ibrs_%(ll):
> (and this continues)
> 
> I had just run freebsd-update:
> 
>     pughole# freebsd-version
>     11.1-RELEASE-p10
> 
> 
>     pughole# cc --version
>     FreeBSD clang version 4.0.0 (tags/RELEASE_400/final 297347) (based on
LLVM 4.0.0)
>     Target: x86_64-unknown-freebsd11.1
>     Thread model: posix
>     InstalledDir: /usr/bin
> 
> I know that clang has been updated a lot; has the kernel source gotten
> ahead of clang on stable/11?
On stable/11 they are in sync.  The official method of upgrade is
	make buildworld buildkernel
from older version takes care of the compiler version transparently.
If you use config/make, ensure that the installed world is at the
compatible level for the kernel sources.

Another option might be stopping using integrated clang assembler, there
is some option in out build system for that, but I do not know it enough
to remember.

[details omittied]
> > I know that clang has been updated a lot; has the kernel source gotten
> > ahead of clang on stable/11?
> On stable/11 they are in sync.  The official method of upgrade is
> 	make buildworld buildkernel
> from older version takes care of the compiler version transparently.
> If you use config/make, ensure that the installed world is at the
> compatible level for the kernel sources.
So the freebsd-update version is not in sync with the -stable branch?
That was not at all obvious to me.  I upgrade from source on my -current
test system, but normally use freebsd-update on my production systems
(until it failed to update the kernel).

		Mike