libdwelf: add dwelf_elf_remove_debug_relocsupstream/users/amerey/try-remove-relocs2

Provide a public function for removing debug section relocations.

eu-strip previously contained the code to remove debug section
relocations.  This patch moves that code into
dwelf_elf_remove_debug_relocs.

https://sourceware.org/bugzilla/show_bug.cgi?id=31447

Signed-off-by: Di Chen <[email protected]>
Signed-off-by: Aaron Merey <[email protected]>

4 files changed, 96 insertions, 1 deletions

diff --git a/tests/Makefile.am b/tests/Makefile.am
index ffccb0cd..a3c4a745 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -59,7 +59,7 @@ check_PROGRAMS = arextract arsymtest newfile saridx scnnames sectiondump \
 		  get-units-invalid get-units-split attr-integrate-skel \
 		  all-dwarf-ranges unit-info next_cfi \
 		  elfcopy addsections xlate_notes elfrdwrnop \
-		  dwelf_elf_e_machine_string \
+		  dwelf_elf_e_machine_string remove-relocs \
 		  getphdrnum leb128 read_unaligned \
 		  msg_tst system-elf-libelf-test system-elf-gelf-test \
 		  nvidia_extended_linemap_libdw elf-print-reloc-syms \
@@ -204,6 +204,7 @@ TESTS = run-arextract.sh run-arsymtest.sh run-ar.sh newfile test-nlist \
 	run-strip-version.sh run-xlate-note.sh \
 	run-readelf-discr.sh \
 	run-dwelf_elf_e_machine_string.sh \
+	run-remove-relocs.sh \
 	run-elfclassify.sh run-elfclassify-self.sh \
 	run-disasm-riscv64.sh \
 	run-pt_gnu_prop-tests.sh \
@@ -576,6 +577,7 @@ EXTRA_DIST = run-arextract.sh run-arsymtest.sh run-ar.sh \
 	     run-readelf-discr.sh \
 	     testfile-rng.debug.bz2 testfile-urng.debug.bz2 \
 	     run-dwelf_elf_e_machine_string.sh \
+	     run-remove-relocs.sh testfile-remove-relocs.bz2 \
 	     run-elfclassify.sh run-elfclassify-self.sh \
 	     run-disasm-riscv64.sh \
 	     testfile-riscv64-dis1.o.bz2 testfile-riscv64-dis1.expect.bz2 \
@@ -856,6 +858,7 @@ debuginfod_build_id_find_LDADD = $(libelf) $(libdw)
 xlate_notes_LDADD = $(libelf)
 elfrdwrnop_LDADD = $(libelf)
 dwelf_elf_e_machine_string_LDADD = $(libelf) $(libdw)
+remove_relocs_LDADD = $(libelf) $(libdw)
 getphdrnum_LDADD = $(libelf) $(libdw)
 leb128_LDADD = $(libelf) $(libdw)
 read_unaligned_LDADD = $(libelf) $(libdw)
diff --git a/tests/remove-relocs.c b/tests/remove-relocs.c
new file mode 100644
index 00000000..9a678f59
--- /dev/null
+++ b/tests/remove-relocs.c
@@ -0,0 +1,38 @@
+/* Test program for dwelf_elf_remove_debug_relocs
+   Copyright (C) 2024 Red Hat, Inc.
+   This file is part of elfutils.
+
+   This file is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   elfutils 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 General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include <fcntl.h>
+#include ELFUTILS_HEADER(dw)
+#include ELFUTILS_HEADER(dwelf)
+
+int main(int argc __attribute__ ((unused)), char **argv) {
+  Elf *elf;
+  elf_version (EV_CURRENT);
+  int fd = open (argv[1], O_RDWR);
+
+  elf = elf_begin (fd, ELF_C_RDWR, NULL);
+
+  dwelf_elf_remove_debug_relocations (elf);
+  elf_update (elf, ELF_C_WRITE);
+
+  elf_end (elf);
+  return 0;
+}
diff --git a/tests/run-remove-relocs.sh b/tests/run-remove-relocs.sh
new file mode 100755
index 00000000..3a49a5ab
--- /dev/null
+++ b/tests/run-remove-relocs.sh
@@ -0,0 +1,54 @@
+#! /usr/bin/env bash
+# Test dwelf_elf_remove_debug_relocations
+# Copyright (C) 2024 Red Hat, Inc.
+# This file is part of elfutils.
+#
+# This file is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# elfutils 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 General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+. $srcdir/test-subr.sh
+
+# = qq.c =
+# int add (int a, int b)
+# {
+#   return a+b;
+# }
+#
+# int main()
+# {
+#   return 0;
+# }
+
+# Using gcc (GCC) 14.2.1 20240801 (Red Hat 14.2.1-1)
+# gcc -g -c qq.c -o testfile-remove-relocs
+
+testfiles testfile-remove-relocs
+
+# Before debug relocations are removed some indices into string tables are
+# set to a default value of 0.  This causes incorrect file and function
+# names to be displayed.
+testrun_compare ${abs_builddir}/allfcts testfile-remove-relocs <<\EOF
+qq.c/qq.c:6:GNU C17 14.2.1 20240801 (Red Hat 14.2.1-1) -mtune=generic -march=x86-64 -g
+qq.c/qq.c:1:add
+EOF
+
+# Remove debug relocations and write the changes to the testfile.
+testrun ${abs_builddir}/remove-relocs testfile-remove-relocs
+
+# Correct file and function names should now be displayed.
+testrun_compare ${abs_builddir}/allfcts testfile-remove-relocs <<\EOF
+/home/dichen/elfutils/tests/qq.c:6:main
+/home/dichen/elfutils/tests/qq.c:1:add
+EOF
+
+exit 0
diff --git a/tests/testfile-remove-relocs.bz2 b/tests/testfile-remove-relocs.bz2
new file mode 100644
index 00000000..2f7ca9b6
--- /dev/null
+++ b/tests/testfile-remove-relocs.bz2