The assertion is this one in ppc_build_one_stub
BFD_ASSERT (stub_entry->stub_offset >= stub_entry->group->stub_sec->size);
It is checking that a stub doesn't overwrite the tail of a previous
stub, so not something trivial.
Normally, stub sizing iterates until no stubs are added, detected by
no change in stub section size. Iteration also continues if no stubs
are added but one or more stubs increases in size, which also can be
detected by a change in stub section size. But there is a
pathological case where stub section sizing decreases one iteration
then increases the next. To handle that situation, stub sizing also
stops at more than STUB_SHRINK_ITER (20) iterations when calculated
stub section size is smaller. The previous larger size is kept for
the actual layout (so that building the stubs, which behaves like
another iteration of stub sizing, will see the stub section sizes
shrink). The problem with that stopping condition is that it assumes
that stub sizing is only affected by addresses external to the stub
sections, which isn't always true.
This patch fixes that by also keeping larger individual stub_offset
addresses past STUB_SHRINK_ITER. It also catches a further
pathological case where one stub shrinks and another expands in such a
way that no stub section size change is seen.
PR 28827
* elf64-ppc.c (struct ppc_link_hash_table): Add stub_changed.
(STUB_SHRINK_ITER): Move earlier in file.
(ppc_size_one_stub): Detect any change in stub_offset. Keep
larger one if past STUB_SHRINK_ITER.
(ppc64_elf_size_stubs): Iterate on stub_changed too.
Make bfd.stamp depend on source bfd.texi to avoid regenerating
doc/bfd.info for each make run.
PR binutils/28807
* Makefile.in: Regenerate.
* doc/local.mk (%D%/bfd.stamp): Depend on $(srcdir)/%D%/bfd.texi.
Rename bfdlib_LTLIBRARIES and bfdinclude_HEADERS to lib_LTLIBRARIES and
include_HEADERS to fix the missing installed library and header files in
bfd caused by
commit bd32be01c9
Author: Mike Frysinger <vapier@gentoo.org>
Date: Fri Dec 3 00:23:20 2021 -0500
bfd: merge doc subdir up a level
PR binutils/28807
* Makefile.am (bfdlib_LTLIBRARIES): Renamed to ...
(lib_LTLIBRARIES): This.
(bfdinclude_HEADERS): Renamed to ...
(include_HEADERS): This.
* Makefile.in: Regenerate.
* doc/local.mk (install): Removed.
This is a generated file name from a correspondingly named C file.
Rename it to avoid unique build rules since there's no difference
to the generated manual.
More fun with R_PPC64_NONE found in .opd. Fixed by the
allocate_dynrelocs and ppc64_elf_size_dynamic_sections changes, and
since we are doing ifunc, opd and SYMBOL_REFERENCES_LOCAL tests later,
don't duplicate that work in check_relocs.
* elf64-ppc.c (ppc64_elf_check_relocs): Remove opd and ifunc
conditions for rel_count.
(dec_dynrel_count): Likewise.
(allocate_dynrelocs): Test for opd and ifunc when allocating
relative relocs.
(ppc64_elf_size_dynamic_sections): Likewise.
Similarly to the local GOT case.
* elf64-ppc.c (ppc64_elf_size_dynamic_sections): Don't allocate
space for PLT relocs against local syms when enable_dt_relr.
Fixes another case where we end up with superfluous R_PPC64_NONE.
* elf64-ppc.c (ppc64_elf_size_dynamic_sections): Don't allocate
space for GOT relocs against non-TLS local syms when enable_dt_relr.
(ppc64_elf_layout_multitoc): Likewise.
HJ: "There are 238 R_PPC64_NONEs in libc.so.6 alone."
Indeed, let's make them go away. I had the SYMBOL_REFERENCES_LOCAL
test in the wrong place. check_relocs is too early to know whether a
symbol is dynamic in a shared library. Lots of glibc symbols are made
local by version script, but that doesn't happen until
size_dynamic_sections.
* elf64-ppc.c (ppc64_elf_check_relocs): Don't count relative relocs
here depending on SYMBOL_REFERENCES_LOCAL.
(dec_dynrel_count): Likewise.
(allocate_dynrelocs): Do so here instead.
I see this error with clang-14:
CC elf64-ppc.lo
/home/smarchi/src/binutils-gdb/bfd/elf64-ppc.c:13131:11: error: use of bitwise '&' with boolean operands [-Werror,-Wbitwise-instead-of-logical]
return (check_pasted_section (info, ".init")
~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Fix by replacing & with &&. But given that the check_pasted_section
function has side-effects and we want to make sure both calls are made,
assign to temporary variables before evaluating the `&&`.
Change-Id: I849e1b2401bea5f4d8ef3ab9af99ba9e3ef42490
PowerPC64 takes a more traditional approach to DT_RELR than x86. Count
relative relocs in check_relocs, allocate space for them and output in
the usual places but not doing so when enable_dt_relr. DT_RELR is
sized in the existing ppc stub relaxation machinery, run via the
linker's ldemul_after_allocation hook. DT_RELR is output in the same
function that writes ppc stubs, run via ldemul_finish.
This support should be considered experimental.
bfd/
* elf64-ppc.c (struct ppc_local_dyn_relocs): Renamed from
ppc_dyn_relocs. Add rel_count field. Update uses.
(struct ppc_dyn_relocs): New. Replace all uses of elf_dyn_relocs.
(struct ppc_link_hash_table): Add relr_alloc, relr_count and
relr_addr.
(ppc64_elf_copy_indirect_symbol): Merge rel_count.
(ppc64_elf_check_relocs): Init rel_count for global and local syms.
(dec_dynrel_count): Change r_info param to reloc pointer. Update
all callers. Handle decrementing rel_count.
(allocate_got): Don't allocate space for relative relocs when
enable_dt_relr.
(allocate_dynrelocs): Likewise.
(ppc64_elf_size_dynamic_sections): Likewise. Handle srelrdyn.
(ppc_build_one_stub): Don't emit relative relocs on .branch_lt.
(compare_relr_address, append_relr_off): New functions.
(got_and_plt_relr_for_local_syms, got_and_plt_relr): Likewise.
(ppc64_elf_size_stubs): Size .relr.syn.
(ppc64_elf_build_stubs): Emit .relr.dyn.
(build_global_entry_stubs_and_plt): Don't output relative relocs
when enable_dt_relr.
(write_plt_relocs_for_local_syms): Likewise.
(ppc64_elf_relocate_section): Likewise.
binutils/
* testsuite/lib/binutils-common.exp (supports_dt_relr): Add
powerpc64.
ld/
* emulparams/elf64ppc.sh: Source dt-relr.sh.
* testsuite/ld-elf/dt-relr-2b.d: Adjust for powerpc.
* testsuite/ld-elf/dt-relr-2c.d: Likewise.
* testsuite/ld-elf/dt-relr-2d.d: Likewise.
* testsuite/ld-elf/dt-relr-2e.d: Likewise.
bfd/
* elf-bfd.h (UNDEFWEAK_NO_DYNAMIC_RELOC): Test linker_def.
ld/
* ldelf.c (ldelf_before_allocation): Don't force __ehdr_start
local and hidden here..
* ldlang.c (lang_symbol_tweaks): ..do so here instead and set
def_regular and linker_def for check_relocs. New function
extracted from lang_process.
tc-ppc.c: In function 'ppc_comm':
tc-ppc.c:4560:40: error: 'visibility' may be used uninitialized in this function [-Werror=maybe-uninitialized]
With that fixed we hit lots of segfaults in the ld testsuite.
PR 22085
bfd/
* xcofflink.c (xcoff_link_input_bfd): Don't segfault on NULL
sym_hash.
gas/
* config/tc-ppc.c (ppc_comm): Init visibility.
This makes the code setting DT_RELR tags generally available. Many
targets will be able to use the defaults. Those that can't should set
up sh_entsize for .relr.dyn output section before reaching the dynamic
tag code in bfd_elf_final_link.
* elflink.c (bfd_elf_final_link): Set up DT_RELR tags and sh_entsize.
* elfxx-x86.c (_bfd_x86_elf_finish_dynamic_sections): Don't do any
of that here.
When DT_RELR is enabled, to avoid random run-time crash with older glibc
binaries without DT_RELR support, add a GLIBC_ABI_DT_RELR symbol version,
which is provided by glibc with DT_RELR support, dependency on the shared
C library if it provides a GLIBC_2.XX symbol version.
bfd/
* elflink.c (elf_link_add_dt_relr_dependency): New function.
(bfd_elf_size_dynamic_sections): Call
elf_link_add_dt_relr_dependency if DT_RELR is enabled.
ld/
* ld.texi: Mention GLIBC_ABI_DT_RELR in -z pack-relative-relocs
entry.
* testsuite/ld-elf/dt-relr-glibc-1.c: New file.
* testsuite/ld-elf/dt-relr-glibc-1a.rd: Likewise.
* testsuite/ld-elf/dt-relr-glibc-1b.rd: Likewise.
* testsuite/ld-elf/dt-relr.exp: Likewise.
DT_RELR is implemented with linker relaxation:
1. During linker relaxation, we scan input relocations with the same
logic in relocate_section to determine if a relative relocation should
be generated and save the relative relocation candidate information for
sizing the DT_RELR section later after all symbols addresses can be
determined. For these relative relocations which can't be placed in
the DT_RELR section, they will be placed in the rela.dyn/rel.dyn
section.
2. When DT_RELR is enabled, _bfd_elf_map_sections_to_segments calls a
backend function to size the DT_RELR section which will compute the
DT_RELR section size and tell ldelf_map_segments to layout sections
again when the DT_RELR section size has been increased.
3. After regular symbol processing is finished, bfd_elf_final_link calls
a backend function to finish the DT_RELR section.
* elf32-i386.c (elf_i386_relocate_section): Don't generate
relative relocation when DT_RELR is enabled.
(elf_i386_finish_dynamic_symbol): Likewise.
* elf64-x86-64.c (elf_x86_64_relocate_section): Don't generate
relative relocation when DT_RELR is enabled.
(elf_x86_64_finish_dynamic_symbol): Likewise.
* elfxx-x86.c (_bfd_x86_elf_link_hash_table_create): Initialize
relative_r_type, relative_r_name, elf_append_reloc,
elf_write_addend and elf_write_addend_in_got.
(elf_x86_relative_reloc_record_add): New function.
(_bfd_x86_elf_link_relax_section): Likewise.
(elf64_dt_relr_bitmap_add): Likewise.
(elf32_dt_relr_bitmap_add): Likewise.
(_bfd_elf32_write_addend): Likewise.
(_bfd_elf64_write_addend): Likewise.
(elf_x86_size_or_finish_relative_reloc): Likewise.
(elf_x86_compute_dl_relr_bitmap): Likewise.
(elf_x86_write_dl_relr_bitmap): Likewise.
(elf_x86_relative_reloc_compare ): Likewise.
(_bfd_elf_x86_size_relative_relocs): Likewise.
(_bfd_elf_x86_finish_relative_relocs): Likewise.
(_bfd_x86_elf_size_dynamic_sections): Skip the .relr.dyn section.
(_bfd_x86_elf_finish_dynamic_sections): Convert 3 spare dynamic
tags to DT_RELR, DT_RELRSZ and for compact relative relocation.
* elfxx-x86.h (X86_64_GOT_TYPE_P): New.
(I386_GOT_TYPE_P): Likewise.
(X86_GOT_TYPE_P): Likewise.
(X86_64_RELATIVE_RELOC_TYPE_P): Likewise.
(I386_RELATIVE_RELOC_TYPE_P): Likewise.
(X86_RELATIVE_RELOC_TYPE_P): Likewise.
(X86_LOCAL_GOT_RELATIVE_RELOC_P): Likewise.
(I386_PCREL_TYPE_P): Likewise.
(X86_64_PCREL_TYPE_P): Likewise.
(X86_64_NEED_DYNAMIC_RELOC_TYPE_P): Rewrite.
(I386_NEED_DYNAMIC_RELOC_TYPE_P): Likewise.
(GENERATE_DYNAMIC_RELOCATION_P): Also check rel_from_abs.
(elf_x86_link_hash_entry): Add got_relative_reloc_done.
(elf_x86_relative_reloc_record): New.
(elf_x86_relative_reloc_data): Likewise.
(elf_dt_relr_bitmap): Likewise.
(elf_x86_link_hash_table): Add dt_relr_bitmap, relative_reloc,
unaligned_relative_reloc, relative_r_type, relative_r_name,
elf_append_reloc, elf_write_addend, elf_write_addend_in_got and
relative_reloc_done.
(elf_x86_relative_reloc_done): New.
(relative_reloc_packed): Likewise.
(_bfd_x86_elf_link_relax_section): Likewise.
(_bfd_elf_x86_size_relative_relocs): Likewise.
(_bfd_elf_x86_finish_relative_relocs): Likewise.
(_bfd_elf32_write_addend): Likewise.
(_bfd_elf64_write_addend): Likewise.
(bfd_elf32_bfd_relax_section): Likewise.
(bfd_elf64_bfd_relax_section): Likewise.
(elf_backend_size_relative_relocs): Likewise.
(elf_backend_finish_relative_relocs): Likewise.
(elf_x86_allocate_local_got_info): Also allocate
relative_reloc_done.
On some targets, the DT_RELR section size can be computed only after all
symbols addresses can be determined. Set the preliminary DT_RELR section
size before mapping sections to segments and set the final DT_RELR section
size after regular symbol processing is done.
* elf-bfd.h (elf_backend_data): Add size_relative_relocs and
finish_relative_relocs.
* elf.c (_bfd_elf_map_sections_to_segments): Call
size_relative_relocs if DT_RELR is enabled.
* elflink.c (bfd_elf_final_link): Call finish_relative_relocs
after regular symbol processing is finished if DT_RELR is enabled.
* elfxx-target.h (elf_backend_size_relative_relocs): New.
(elf_backend_finish_relative_relocs): Likewise.
(elfNN_bed): Add elf_backend_size_relative_relocs and
elf_backend_finish_relative_relocs.
Add a -z pack-relative-relocs option to enable DT_RELR and create a
relr.dyn section for DT_RELR. DT_RELR is implemented with the linker
relaxation infrastructure, but it doesn't require the --relax option
enabled. -z pack-relative-relocs implies -z combreloc. -z nocombreloc
implies -z nopack-relative-relocs.
-z pack-relative-relocs is chosen over the similar option in lld,
--pack-dyn-relocs=relr, to implement a glibc binary lockout mechanism
with a special glibc version symbol, to avoid random crashes of DT_RELR
binaries with the existing glibc binaries.
bfd/
* elf-bfd.h (elf_link_hash_table): Add srelrdyn.
* elflink.c (_bfd_elf_link_create_dynamic_sections): Create a
.relr.dyn section for DT_RELR.
include/
* bfdlink.h (bfd_link_info): Add enable_dt_relr.
ld/
* News: Mention -z pack-relative-relocs and
-z nopack-relative-relocs.
* ld.texi: Document -z pack-relative-relocs and
-z nopack-relative-relocs.
* ldelf.c (ldelf_after_parse): Disable DT_RELR if not building
PIE nor shared library. Add 3 spare dynamic tags for DT_RELR,
DT_RELRSZ and DT_RELRENT.
* ldlang.c (lang_relax_sections): Also enable relaxation if
DT_RELR is enabled.
* emulparams/elf32_x86_64.sh: Source dt-relr.sh.
* emulparams/elf_i386.sh: Likewise.
* emulparams/elf_x86_64.sh: Likewise.
* emulparams/dt-relr.sh: New file.
* scripttempl/elf.sc: Support .relr.dyn.
