Re: [PATCH] Add check-symbol-verion.awk

From 567ca328d3138f6b06a8cdb88cd8511f66ed99fd Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <[email protected]>
Date: Wed, 26 Aug 2026 15:18:35 +0800
Subject: [PATCH] Add check-symbol-version.awk

commit 6deadd4eb6ab4f59d116b2d7ad97be0d0848cb7f
Author: Adhemerval Zanella <[email protected]>
Date:   Wed Oct 8 10:55:05 2025 -0300

didn't remove sysdeps/m68k/m680x0/fpu/w_fmod_compat.c.  As the result,
due to a linker bug:

https://sourceware.org/bugzilla/show_bug.cgi?id=34550

there were 2 default versions of fmod in m68k libm:

   996: 0001433c   174 FUNC    WEAK   DEFAULT   12 fmod@@GLIBC_2.0
   997: 000307d4   214 FUNC    GLOBAL DEFAULT   12 fmod@@GLIBC_2.43

Add check-symbol-version.awk to verify that versioned symbols only have
one default version in dynamic symbol table.

Signed-off-by: H.J. Lu <[email protected]>
Reviewed-by: Sam James <[email protected]>

Signed-off-by: H.J. Lu <[email protected]>
---
 elf/Makefile                     |  7 ++++
 scripts/check-symbol-version.awk | 67 ++++++++++++++++++++++++++++++++
 2 files changed, 74 insertions(+)
 create mode 100644 scripts/check-symbol-version.awk

diff --git a/elf/Makefile b/elf/Makefile
index c5bf1f38cb..9ed57f1c29 100644
--- a/elf/Makefile
+++ b/elf/Makefile
@@ -1436,6 +1436,7 @@ tests-special += \
   $(objpfx)check-execstack.out \
   $(objpfx)check-initfini.out \
   $(objpfx)check-localplt.out \
+  $(objpfx)check-symbol-version.out \
   $(objpfx)check-textrel.out \
   $(objpfx)check-wx-segment.out \
   # tests-special
@@ -2381,6 +2382,12 @@ $(objpfx)check-initfini.out: $(..)scripts/check-initfini.awk \
 	$(evaluate-test)
 generated += check-initfini.out
 
+$(objpfx)check-symbol-version.out: $(..)scripts/check-symbol-version.awk \
+			    $(all-built-dso:=.dynsym)
+	LC_ALL=C $(AWK) -f $^ > $@; \
+	$(evaluate-test)
+generated += check-symbol-version.out
+
 $(objpfx)tst-dlopenrpath: $(objpfx)tst-dlopenrpathmod.so
 CFLAGS-tst-dlopenrpath.c += -DPFX=\"$(objpfx)\"
 LDFLAGS-tst-dlopenrpathmod.so += -Wl,-rpath,\$$ORIGIN/test-subdir
diff --git a/scripts/check-symbol-version.awk b/scripts/check-symbol-version.awk
new file mode 100644
index 0000000000..2ddaa0edc9
--- /dev/null
+++ b/scripts/check-symbol-version.awk
@@ -0,0 +1,67 @@
+# Copyright (C) 2026 Free Software Foundation, Inc.
+# This file is part of the GNU C Library.
+
+# The GNU C Library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+
+# The GNU C Library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+
+# You should have received a copy of the GNU Lesser General Public
+# License along with the GNU C Library; if not, see
+# <https://www.gnu.org/licenses/>.
+
+# This awk script expects to get command-line files that are each
+# the output of 'readelf -W --dyn-syms' on a single shared object.
+# It exits successfully (0) if there are versioned symbols with more
+# than one default version in dynamic symbol table.
+# It fails (1) if any did contain versioned symbols with more than one
+# default version in dynamic symbol table.
+# It fails (2) if the input did not take the expected form.
+
+BEGIN { result = incorrect = sanity = 0 }
+
+function check_one(name) {
+  if (!sanity) {
+    print name ": *** input did not look like readelf -d output";
+    result = 2;
+  } else {
+    ok = 1;
+    if (incorrect) {
+      print name ": *** incorrect dynamic symbol table";
+      result = result ? result : 1;
+      ok = 0;
+    }
+    if (ok)
+      print name ": OK";
+  }
+
+  delete version
+  incorrect = sanity = 0
+}
+
+FILENAME != lastfile {
+  if (lastfile)
+    check_one(lastfile);
+  lastfile = FILENAME;
+}
+
+$1 == "Symbol" && $2 == "table" && $3 == "'.dynsym'" { sanity = 1 }
+$8 ~ "@@" {
+  split($8,a,"@");
+  if (version[a[1]] != "") {
+    incorrect = 1;
+    print a[1] " has 2 default versions: " version[a[1]] ", " a[3];
+  } else {
+    version[a[1]] = a[3];
+  }
+}
+
+END {
+  check_one(lastfile);
+  exit(result);
+}
-- 
2.55.0