Weird bug (maybe in clang - inetd.c does not compile without INET6)

Hi,

I am building my systems from source and usually with WITHOUT_INET6
knob among others. Partly inertia, partly minimalisation, partly
speedup. At the moment, my boxes are at 15-STABLE, last working build
is from May 30, 2026, git hash cfbe04310e254890c471f97f03dc7c3c5e9af01c
- that's with compiler

# cc -v
FreeBSD clang version 19.1.7 (https://github.com/llvm/llvm-project.git llvmorg-19.1.7-0-gcd708029e0b2)

Then new LLVM is being imported, builds do not work with error

---- 8< ------------------------------------------------------------

===> usr.bin/clang/llvm-min-tblgen (obj,all,install)
make[3]: don't know how to make TableGen.cpp. Stop

make[3]: stopped making "all" in /usr/src/usr.bin/clang/llvm-min-tblgen
*** Error code 2

Stop.
make[2]: stopped making "bootstrap-tools" in /usr/src
        0.40 real         0.16 user         0.04 sys
*** Error code 1

Stop.
make[1]: stopped making "buildworld" in /usr/src
*** Error code 1

Stop.
make: stopped making "buildworld" in /usr/src

---- 8< ------------------------------------------------------------

for commits 0008bdb8bd28d1c15670084ca63015b551a33f76,
c76ec29427955975909939e41052e19d000cf008,
85298a854720b7e712d4500b8d6ca340f6c39dd8,
4575fcccafed03e93f306ddd287229c4568e7280 - import was divided into more
commits.

Next commits does not build as well, with different error:

---- 8< ------------------------------------------------------------

In file included from
/usr/src/contrib/llvm-project/libcxx/src/algorithm.cpp:9: In file
included from
/usr/src/contrib/llvm-project/libcxx/include/algorithm:1865: In file
included from
/usr/src/contrib/llvm-project/libcxx/include/__algorithm/inplace_merge.h:27:
In file included from
/usr/src/contrib/llvm-project/libcxx/include/__memory/unique_ptr.h:48:
/usr/src/contrib/llvm-project/libcxx/include/__type_traits/remove_extent.h:9:2:
error: unterminated conditional directive 9 | #ifndef
_LIBCPP___TYPE_TRAITS_REMOVE_EXTENT_H |  ^ 3 errors generated. ***
Error code 1

Stop.
make[4]: stopped making "all" in /usr/src/lib/libc++
*** Error code 1

Stop.
make[3]: stopped making "_prebuild_libs" in /usr/src
*** Error code 1

Stop.
make[2]: stopped making "libraries" in /usr/src
        8.67 real         6.56 user         0.65 sys
*** Error code 1

Stop.
make[1]: stopped making "buildworld" in /usr/src
*** Error code 1

Stop.
make: stopped making "buildworld" in /usr/src

---- 8< ------------------------------------------------------------

Commits were fe97aeb6c4fb57f9cd3ae834e66d85bcb36b91ee,
cf7d88e89f1dcc1b66c3e8f327e16122d42d6a6c,
d08fb64ae2157d3bc65777589728e880e6409d72,
c1db7ad65d704e4ae81bbfe7bdaf049120d324a2 - I think with those import of
new LLVM is being finished.

Now, one could expect things going back to normal, but for me, with
WITHOUT_INET6 knob in action, did not work, the error is

---- 8< ------------------------------------------------------------

===> usr.sbin/inetd (all)
cc -target x86_64-unknown-freebsd15.1
--sysroot=/usr/obj/usr/src/amd64.amd64/tmp
-B/usr/obj/usr/src/amd64.amd64/tmp/usr/bin -fpie -DPIC   -O2 -pipe
-fno-common   -DLOGIN_CAP -DLIBWRAP -DIPSEC -fPIE
-ffile-prefix-map=/usr/src=/usr/src
-ffile-prefix-map=/usr/obj/usr/src=/usr/obj -MD  -MF.depend.inetd.pieo
-MTinetd.pieo -std=gnu17 -Wno-format-zero-length
-fstack-protector-strong -Wsystem-headers -Werror -Wall -Wno-format-y2k
-W -Wno-unused-parameter -Wstrict-prototypes -Wmissing-prototypes
-Wpointer-arith -Wreturn-type -Wcast-qual -Wwrite-strings -Wswitch
-Wshadow -Wunused-parameter -Wcast-align -Wchar-subscripts
-Wnested-externs -Wold-style-definition -Wno-pointer-sign -Wdate-time
-Wmissing-variable-declarations -Wthread-safety -Wno-empty-body
-Wno-string-plus-int -Wno-unused-const-variable
-Wno-error=unused-but-set-parameter
-Wno-error=cast-function-type-mismatch  -Qunused-arguments      -c
/usr/src/usr.sbin/inetd/inetd.c -o inetd.pieo
/usr/src/usr.sbin/inetd/inetd.c:737:26: warning: cast from 'struct
servtab *(*)(int)' to 'bi_fn_t *' (aka 'void (*)(int, struct servtab
*)') converts to incompatible function type
[-Wcast-function-type-mismatch] 737 |
sep->se_bi->bi_fn == (bi_fn_t *) tcpmux) { |
                          ^~~~~~~~~~~~~~~~~~
/usr/src/usr.sbin/inetd/inetd.c:1365:44: error: variable 'nbuf2' is
uninitialized when passed as a const pointer argument here
[-Werror,-Wuninitialized-const-pointer] 1365 |
       rpcb_set(sep->se_rpc_prog, i, netid2, &nbuf2); |
                                                       ^~~~~ 1 warning
and 1 error generated. *** Error code 1

Stop.
make[4]: stopped making "all" in /usr/src/usr.sbin/inetd
*** Error code 1

Stop.
make[3]: stopped making "all" in /usr/src/usr.sbin
*** Error code 1

Stop.
make[2]: stopped making "all" in /usr/src
       39.48 real        17.22 user         3.71 sys
*** Error code 1

Stop.
make[1]: stopped making "buildworld" in /usr/src
*** Error code 1

Stop.
make: stopped making "buildworld" in /usr/src

---- 8< ------------------------------------------------------------

The error points to function setup, which, after looking into it,
should compile just fine when INET6 is not defined, but, for some
reason not known to me, does not. There was no change in inetd.c source
file, compiler was changed, it is now

# cc -v
FreeBSD clang version 21.1.7 (https://github.com/llvm/llvm-project.git llvmorg-21.1.7-0-gcd708029e0b2)

I used simple 'brute force' patch for this, see attachment, which
allowed me to finish the build process and after installing run the
resulting system as usual.

Addition:

I tried with recent trees as well, yesterday's commit
cfc5ebfeb889a0e894f94bfe45ee1ba4338ececb and today's commit
f310b83defebddcb0fab9fbb4d9629ea8d0a2f04, with the same result -
inetd.c does not compile, even when using newer clang

# cc -v
FreeBSD clang version 21.1.8 (https://github.com/llvm/llvm-project.git llvmorg-21.1.8-0-g2078da43e25a)

Applying my patch solves the issue.

Conclusion:

I think we either have a bug in clang toolchain - I see the file being
succesfully compiled with older clang, and working, or newer clang
shows more problem tan older one, and then polishing and applying my
patch is appropriate. While I work with 15-STABLE sources, I verified
the file inetd.c is exactly the same in CURRENT sources.

Regards,
Milan

--- inetd.c.orig	2026-08-14 19:10:15.866775000 +0200
+++ inetd.c	2026-08-16 17:13:16.947397000 +0200
@@ -1315,11 +1315,15 @@
         if (sep->se_rpc) {
 		u_int i;
 		socklen_t len = sep->se_ctrladdr_size;
-		struct netconfig *netid, *netid2 = NULL;
+		struct netconfig *netid;
 #ifdef INET6
+		struct netconfig *netid2 = NULL;
 		struct sockaddr_in sock;
 #endif
-		struct netbuf nbuf, nbuf2;
+		struct netbuf nbuf;
+#ifdef INET6
+		struct netbuf nbuf2;
+#endif
 
                 if (getsockname(sep->se_fd,
 				(struct sockaddr*)&sep->se_ctrladdr, &len) < 0){
@@ -1360,10 +1364,12 @@
                 for (i = sep->se_rpc_lowvers; i <= sep->se_rpc_highvers; i++) {
 			rpcb_unset(sep->se_rpc_prog, i, netid);
 			rpcb_set(sep->se_rpc_prog, i, netid, &nbuf);
+#ifdef INET6
 			if (netid2) {
 				rpcb_unset(sep->se_rpc_prog, i, netid2);
 				rpcb_set(sep->se_rpc_prog, i, netid2, &nbuf2);
 			}
+#endif
                 }
         }
 	if (sep->se_socktype == SOCK_STREAM)