[PATCH v3] elf: Don't set its DT_VERSYM entry for unversioned symbol

[H.J. Lu]

On Tue, Nov 11, 2025 at 6:46 PM Andreas Schwab <schwab@suse.de> wrote:
>
> On Okt 31 2025, H.J. Lu wrote:
>
> > 1. Referenced symbol without '@' has no version.
> > 2. Defined symbol without the .symver directive has no version if there
> > is no linker version script.
> >
> > Symbol without version shouldn't have the base version in its DT_VERSYM
> > entry.  Instead, its DT_VERSYM entry should be all zero to indicate that
> > the symbol doesn't have a version.
>
> This breaks the testsuite of mold:
>

Why should ld change impact mold tests?

>  38/428 Test  #38: x86_64-arch-x86_64-reloc ..............................***Failed    0.09 sec
> ++ dirname /home/abuild/rpmbuild/BUILD/mold-2.40.4.60.gad08999-build/mold-2.40.4.60.gad08999/test/arch-x86_64-reloc.sh
> + . /home/abuild/rpmbuild/BUILD/mold-2.40.4.60.gad08999-build/mold-2.40.4.60.gad08999/test/common.inc
> ++ export LC_ALL=C
> ++ LC_ALL=C
> ++ '[' -z x86_64 ']'
> ++ '[' -z '' ']'
> ++ TESTDIR=out/test/x86_64
> ++ CC=cc
> ++ CXX=c++
> ++ GCC=gcc
> ++ GXX=g++
> ++ OBJDUMP=objdump
> ++ OBJCOPY=objcopy
> ++ STRIP=strip
> ++ QEMU=
> +++ basename /home/abuild/rpmbuild/BUILD/mold-2.40.4.60.gad08999-build/mold-2.40.4.60.gad08999/test/arch-x86_64-reloc.sh .sh
> ++ testname=arch-x86_64-reloc
> ++ t=out/test/x86_64/arch-x86_64-reloc
> ++ mkdir -p out/test/x86_64/arch-x86_64-reloc
> ++ case $MACHINE in
> ++ tlsdesc_opt=-mtls-dialect=gnu2
> +++ uname
> ++ '[' Linux = FreeBSD ']'
> ++ trap 'on_error $LINENO' ERR
> ++ trap on_exit EXIT
> ++ echo -n 'Testing arch-x86_64-reloc ... '
> Testing arch-x86_64-reloc ... ++ set -o pipefail
> ++ set -x
> + cat
> + cc -fPIC -c -o out/test/x86_64/arch-x86_64-reloc/a.o -x assembler -
> + cc -fPIC -c -o out/test/x86_64/arch-x86_64-reloc/b.o -xc -
> + cat
> + cc -shared -o out/test/x86_64/arch-x86_64-reloc/c.so out/test/x86_64/arch-x86_64-reloc/a.o out/test/x86_64/arch-x86_64-reloc/b.o -Wl,-z,noexecstack
> + cat
> + cc -B. -o out/test/x86_64/arch-x86_64-reloc/exe out/test/x86_64/arch-x86_64-reloc/c.so out/test/x86_64/arch-x86_64-reloc/d.s -no-pie
> mold: error: undefined symbol: print
> >>> referenced by /tmp/ccfsY4zd.o:(.text)
> >>>               /tmp/ccfsY4zd.o
> collect2: error: ld returned 1 exit status
> ++ on_error 43
> ++ code=1
> ++ echo 'command failed: 43: $CC -B. -o $t/exe $t/c.so $t/d.s -no-pie'
> command failed: 43: $CC -B. -o $t/exe $t/c.so $t/d.s -no-pie
> ++ trap - EXIT
> ++ exit 1
>
> Is this a bug in mold?

Does

$ cc -o out/test/x86_64/arch-x86_64-reloc/exe
out/test/x86_64/arch-x86_64-reloc/c.so
out/test/x86_64/arch-x86_64-reloc/d.s -no-pie

fail with ld?  "print" isn't a function in libc.

1. Where is it defined?
2. What does
"readelf -DsW" with

commit 2be0f2da2100cc2b5047f5d055cd039ac494d563
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Thu Nov 6 08:20:26 2025 +0800

    readelf: Display the base symbol version as empty string

report on the object where "print" is defined.
3.  Which linker is used to generate it?


-- 
H.J.