freebsd stable - Mar 2019 - ifuncs check flawed?

I have been building FreeBSD for many years, as in since 2.2.8.

Currently my amd64 build of 12-STABLE is built with the following src.conf:

WITHOUT_BHYVE=1
WITHOUT_CAPSICUM=1
WITHOUT_CDDL=1
WITHOUT_CLANG_EXTRAS=1
WITHOUT_CLANG_FULL=1
WITHOUT_CROSS_COMPILER=1
WITHOUT_DEBUG_FILES=1
WITHOUT_EXAMPLES=1
WITHOUT_HYPERV=1
WITHOUT_JAIL=1
WITHOUT_LOCALES=1
WITHOUT_PROFILE=1
WITHOUT_QUOTAS=1
WITHOUT_TESTS=1

And a make.conf of:

BATCH=yes
MK_CDDL=no
MK_CLANG_EXTRAS=no
MK_DEBUG_FILES=no
MK_NO_PROFILE=yes
MK_TESTS=no
OPTIONS_UNSET=JAVA
WITH_JADETEX=no
WITHOUT_CDDL=yes
WITHOUT_CLANG_FULL=yes
WITHOUT_CTF=yes
WITHOUT_CTM=yes
DISABLE_VULNERABILITIES=yes

So far, so good.  (I do this to fit the whole thing onto a CD-image.)

Fooling around, and using xhyve on my Mac, I want to build a i386 version in a
VM.

So I grabbed the 20190314 snapshot of 12-STABLE, i386 flavor, and installed it. 
Works great.

Now to rebuild the world.

The buildworld and buildkernel steps both immediately fail due to the linker not
supporting ifuncs.

The code that stops the buildworld is this from /usr/src/lib/libc/Makefile:

---
.if (${LIBC_ARCH} == amd64 || ${LIBC_ARCH} == i386) && \
     ${.TARGETS:Mall} == all && \
     defined(LINKER_FEATURES) && ${LINKER_FEATURES:Mifunc} ==
""
.error ${LIBC_ARCH} libc requires linker ifunc support
.endif
---

However the linker on my system is the lld linker that supports ifuncs!  Why
does this check fail?

I am building on i386 but I am only building i386, as in I am not building all
targets or amd64.

I edited the two Makefiles that have this check to remove the check and the
builds proceed just fine.

So it appears that these checks are flawed, or I am soon to learn something new
about FreeBSD!

Thanks,

Dan Allen

On Mon, 18 Mar 2019 at 13:03, Dan Allen <danallen46 at gmail.com>
wrote:
>
> The buildworld and buildkernel steps both immediately fail due to the
linker not supporting ifuncs.
By default FreeBSD/i386 uses lld as the bootstrap linker (i.e., the
linker used for building the kernel, libraries, and userland binaries)
but still installs GNU ld as /usr/bin/ld on stable/12 due to issues in
the ports tree.

There are a few different ways you could address this:
1. Build either the buildworld or kernel-toolchain targets before make
buildkernel, which will then use the built toolchain including lld.
2. Set LD=ld.lld to explicitly use lld for the kernel link.
3. Build and install world WITH_LLD_IS_LD in src.conf, so that
/usr/bin/ld is lld.