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x86-64: Add GLIBC_ABI_DT_X86_64_PLT version dependency

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On Linux/x86-64, programs and shared libraries created with -z mark-plt
have the GLIBC_2.36 version tag dependency since -z mark-plt uses the
r_addend field of the R_X86_64_JUMP_SLOT relocation to store the offset
of the indirect branch instruction.  Glibc versions which don't have the
commit added to glibc 2.36:

commit f8587a61892cbafd98ce599131bf4f103466f084
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Fri May 20 19:21:48 2022 -0700

    x86-64: Ignore r_addend for R_X86_64_GLOB_DAT/R_X86_64_JUMP_SLOT

won't ignore the r_addend value in the R_X86_64_JUMP_SLOT relocation.  If
glibc versions defines GLIBC_ABI_DT_X86_64_PLT version tag with

commit 399384e0c8193e31aea014220ccfa24300ae5938
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Thu Aug 14 07:03:20 2025 -0700

    x86-64: Add GLIBC_ABI_DT_X86_64_PLT [BZ #33212]

to indicate inclusion of the commit:

commit f8587a61892cbafd98ce599131bf4f103466f084
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Fri May 20 19:21:48 2022 -0700

    x86-64: Ignore r_addend for R_X86_64_GLOB_DAT/R_X86_64_JUMP_SLOT

we can add GLIBC_ABI_DT_X86_64_PLT version tag dependency, instead of
GLIBC_2.36 version tag dependency.

	PR ld/33213
	* elf-bfd.h (_bfd_elf_link_add_glibc_version_dependency): Change
	return type to bool.
	* elf64-x86-64.c (elf_x86_64_add_glibc_version_dependency): Add
	GLIBC_ABI_DT_X86_64_PLT version tag dependency, instead of,
	GLIBC_2.36 version tag dependency, for -z mark-plt if libc.so
	defines GLIBC_ABI_DT_X86_64_PLT version tag.
	* elflink.c (_bfd_elf_link_add_glibc_version_dependency): Change
	return type to bool.  Return false if elf_link_add_glibc_verneed
	returns false.

Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
This commit is contained in:
H.J. Lu
2025-08-17 10:09:25 -07:00
parent 0d1e88f8bf
commit 66e4999f34
4 changed files with 25 additions and 9 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
bfd/elf-bfd.h
View File

@@ -2631,7 +2631,7 @@ extern bool _bfd_elf_link_output_relocs
(bfd *, asection *, Elf_Internal_Shdr *, Elf_Internal_Rela *,
struct elf_link_hash_entry **);
extern void _bfd_elf_link_add_glibc_version_dependency
extern bool _bfd_elf_link_add_glibc_version_dependency
(struct elf_find_verdep_info *, const char *const [], bool *);
extern void _bfd_elf_link_add_dt_relr_dependency

20
bfd/elf64-x86-64.c
View File

@@ -6246,7 +6246,7 @@ static void
elf_x86_64_add_glibc_version_dependency
(struct elf_find_verdep_info *rinfo)
{
unsigned int i = 0;
int i = 0, mark_plt = -1;
const char *version[4] = { NULL, NULL, NULL, NULL };
bool auto_version[4] = { false, false, false, false };
struct elf_x86_link_hash_table *htab;
@@ -6271,12 +6271,26 @@ elf_x86_64_add_glibc_version_dependency
}
if (htab->params->mark_plt)
{
version[i] = "GLIBC_2.36";
mark_plt = i;
auto_version[i] = true;
version[i] = "GLIBC_ABI_DT_X86_64_PLT";
i++;
}
}
if (i != 0)
if (i == 0
|| !_bfd_elf_link_add_glibc_version_dependency (rinfo, version,
auto_version))
return;
if (mark_plt < 0 || auto_version[mark_plt])
return;
/* Add the GLIBC_2.36 version dependency if libc.so doesn't have
GLIBC_ABI_DT_X86_64_PLT. */
version[0] = "GLIBC_2.36";
auto_version[0] = false;
version[1] = NULL;
_bfd_elf_link_add_glibc_version_dependency (rinfo, version,
auto_version);
}

6
bfd/elflink.c
View File

@@ -2399,7 +2399,7 @@ elf_link_add_glibc_verneed (struct elf_find_verdep_info *rinfo,
/* Add VERSION_DEP to the list of version dependencies when linked
against glibc. */
void
bool
_bfd_elf_link_add_glibc_version_dependency
(struct elf_find_verdep_info *rinfo,
const char *const version_dep[],
@@ -2412,11 +2412,13 @@ _bfd_elf_link_add_glibc_version_dependency
/* Return if not linked against glibc. */
if (!elf_link_add_glibc_verneed (rinfo, *version_dep,
&glibc_minor_base, auto_version))
return;
return false;
version_dep++;
auto_version++;
}
while (*version_dep != NULL);
return true;
}
/* Add GLIBC_ABI_DT_RELR to the list of version dependencies when

2
ld/testsuite/ld-x86-64/mark-plt-1a.rd
View File

@@ -3,5 +3,5 @@ Version needs section '.gnu.version_r' contains 1 entry:
Addr: 0x[0-9a-f]+ +Offset: 0x[0-9a-f]+ +Link: +[0-9]+ +\(.dynstr\)
+0+: Version: 1 +File: libc\.so\.6(|\.1) +Cnt: +[0-9]+
#...
0x[a-f0-9]+: Name: GLIBC_2.36 Flags: none Version: [0-9]+
0x[a-f0-9]+: Name: (GLIBC_2.36|GLIBC_ABI_DT_X86_64_PLT) Flags: none Version: [0-9]+
#pass