armv7 target /sys/kern/kern_linker.c build failures for main in personal build (KLD_DPF with __func__ used in argment as if it produced a string literal)

Both non-debug and debug builds got the issue:

--- kern_linker.o ---
/usr/main-src/sys/kern/kern_linker.c:340:16: error: expected ')'
  340 |             (__func__ ": registering exterror categories for %s\n",
      |                       ^
/usr/main-src/sys/kern/kern_linker.c:340:6: note: to match this '('
  340 |             (__func__ ": registering exterror categories for %s\n",
      |             ^
/usr/main-src/sys/kern/kern_linker.c:357:16: error: expected ')'
  357 |             (__func__ ": unregistering exterror categories for
%s\n",
      |                       ^
/usr/main-src/sys/kern/kern_linker.c:357:6: note: to match this '('
  357 |             (__func__ ": unregistering exterror categories for
%s\n",
      |             ^
Building
/usr/obj/BUILDs/main-CA7-nodbg-clang/usr/main-src/arm.armv7/sys/GENERIC-NODBG-CA7/kern_module.o
Building
/usr/obj/BUILDs/main-CA7-nodbg-clang/usr/main-src/arm.armv7/sys/GENERIC-NODBG-CA7/kern_mtxpool.o
2 errors generated.
*** [kern_linker.o] Error code 1


--- kern_linker.o ---
/usr/main-src/sys/kern/kern_linker.c:340:16: error: expected ')'
  340 |             (__func__ ": registering exterror categories for %s\n",
      |                       ^
/usr/main-src/sys/kern/kern_linker.c:340:6: note: to match this '('
  340 |             (__func__ ": registering exterror categories for %s\n",
      |             ^
/usr/main-src/sys/kern/kern_linker.c:357:16: error: expected ')'
  357 |             (__func__ ": unregistering exterror categories for
%s\n",
      |                       ^
/usr/main-src/sys/kern/kern_linker.c:357:6: note: to match this '('
  357 |             (__func__ ": unregistering exterror categories for
%s\n",
      |             ^
Building
/usr/obj/BUILDs/main-CA7-dbg-clang/usr/main-src/arm.armv7/sys/GENERIC-DBG-CA7/kern_mutex.o
2 errors generated.
*** [kern_linker.o] Error code 1


I'll remind that, in C, __func__ is a reference to an implicit, function
local:

static const char __func__[] = "function-name";

and is not a string literal. One cannot concatenate __func__ with a
string literal via adjacent placement (that would be a language extension).

Note: aarch4 did not report such a failure when built from the same
source tree on the same machine. an amd64 system also did not report the
failure when based on a copy of the same source tree.


My prior context predated:

author	Brooks Davis <brooks@FreeBSD.org>	2026-08-03 16:50:01 +0000
committer	Brooks Davis <brooks@FreeBSD.org>	2026-08-03 21:43:23 +0000
commit	295f10230903d54c700518467c4ea4492f5c4faa (patch)
tree	fc76723160a417b8aa23121ff7a8a4e29f634527 /sys/kern/kern_linker.c
parent	bbf95a9b8481e41a99b301e12338e1cda6915a01 (diff)

exterror(9): dynamic kernel categories

Make it possible to define categories without compiling their
paths into libc (important for third-party modules).  The
EXTERR_CATEGORY_DYNAMIC macro can be defined to a string describing the
compilation unit (generally the path relative to src/sys) which takes
the place of EXTERR_CATEGORY.

These strings are assembled in linker sets with category numbers
assigned at system startup or module load time.  The strings can be
retrieved from the kern.exterr.categories.<category> sysctl.

Reviewed by:	kib
Sponsored by:	Innovate UK
Differential Revision:	https://reviews.freebsd.org/D58237

The code from that is:

+static void
+linker_file_register_exterr(linker_file_t lf)
+{
+	struct exterr_cat **start, **stop;
+
+	KLD_DPF(FILE,
+	    (__func__ ": registering exterror categories for %s\n",
+	    lf->filename));
+
+	sx_assert(&kld_sx, SA_XLOCKED);
+
+	if (linker_file_lookup_set(lf, "exterr_cats", &start, &stop, NULL) != 0)
+		return;
+
+	exterr_cat_register_module(start, stop);
+}
+
+static void
+linker_file_unregister_exterr(linker_file_t lf)
+{
+	struct exterr_cat **start, **stop;
+
+	KLD_DPF(FILE,
+	    (__func__ ": unregistering exterror categories for %s\n",
+	    lf->filename));
+
+	sx_assert(&kld_sx, SA_XLOCKED);
+
+	if (linker_file_lookup_set(lf, "exterr_cats", &start, &stop, NULL) != 0)
+		return;
+
+	exterr_cat_unregister_module(start, stop);
+}
+


-- 
===
Mark Millard
marklmi at yahoo.com