This implements padding of orphan executable sections for PowerPC.
Of course, the simple implementation of bfd_arch_ppc_nop_fill and
removing the NOP definition didn't work, with powerpc64 hitting a
testsuite failure linking to S-records. That's because the srec
target is BFD_ENDIAN_UNKNOWN so the test of bfd_big_endian (abfd) in
default_data_link_order therefore returned false, resulting in a
little-endian nop pattern. The rest of the patch fixes that problem
by adding a new field to bfd_link_info that can be used to determine
actual endianness on targets like srec.
PR 13616
include/
* bfdlink.h (struct bfd_link_info <big_endian>): New field.
bfd/
* cpu-powerpc.c (bfd_arch_ppc_nop_fill): New function, use it
for all ppc arch info.
* linker.c (default_data_link_order): Pass info->big_endian to
arch_info->fill function.
ld/
* emulparams/elf64lppc.sh (NOP): Don't define.
* emulparams/elf64ppc.sh (NOP): Don't define.
* ldwrite.c (build_link_order): Use link_info.big_endian. Move
code determining endian to use for data_statement to..
* ldemul.c (after_open_default): ..here. Set link_info.big_endian.
This is quite complicated because the CTF section's contents depend on
the final contents of the symtab and strtab, because it has two sections
whose contents are shuffled to be in 1:1 correspondence with the symtab,
and an internal strtab that gets deduplicated against the ELF strtab
(with offsets adjusted to point into the ELF strtab instead). It is
also compressed if large enough, so its size depends on its contents!
So we cannot construct it as early as most sections: we cannot even
*begin* construction until after the symtab and strtab are finalized.
Thankfully there is already one section treated similarly: compressed
debugging sections: the only differences are that compressed debugging
sections have extra handling to deal with their changing name if
compressed (CTF sections are always called ".ctf" for now, though we
have reserved ".ctf.*" against future use), and that compressed
debugging sections have previously-uncompressed content which has to be
stashed away for later compression, while CTF sections have no content
at all until we generate it (very late).
BFD also cannot do the link itself: libctf knows how to do it, and BFD
cannot call libctf directly because libctf already depends on bfd for
file I/O. So we have to use a pair of callbacks, one, examine_strtab,
which allows a caller to examine the symtab and strtab after
finalization (called from elf_link_swap_symbols_out(), right before the
symtabs are written, and after the strtab has been finalized), and one
which actually does the emission (called emit_ctf simply because it is
grouped with a bunch of section-specific late-emission function calls at
the bottom of bfd_elf_final_link, and a section-specific name seems best
for that). emit_ctf is actually called *twice*: once from lang_process
if the emulation suggests that this bfd target does not examine the
symtab or strtab, and once via a bfd callback if it does. (This means
that non-ELF targets still get CTF emitted, even though the late CTF
emission stage is never called for them).
v2: merged with non-ELF support patch: slight commit message
adjustments.
v3: do not spend time merging CTF, or crash, if the CTF section is
explicitly discarded. Do not try to merge or compress CTF unless
linking.
v4: add CTF_COMPRESSION_THRESHOLD. Annul the freed input ctf_file_t's
after writeout: set SEC_IN_MEMORY on the output contents so a future
bfd enhancement knows it could free it. Add SEC_LINKER_CREATED |
SEC_KEEP to avoid having to add .ctf to the linker script. Drop
now-unnecessary ldlang.h-level elf-bfd.h include and hackery around
it. Adapt to elf32.em->elf.em and elf-generic.em->ldelf*.c
changes.
v5: fix tabdamage. Drop #inclusions in .h files: include in .c files,
.em files, and use struct forwards instead. Use bfd_section_is_ctf
inline function rather than SECTION_IS_CTF macro. Move a few
comments.
* Makefile.def (dependencies): all-ld depends on all-libctf.
* Makefile.in: Regenerated.
include/
* bfdlink.h (elf_strtab_hash): New forward.
(elf_sym_strtab): Likewise.
(struct bfd_link_callbacks <examine_strtab>): New.
(struct bfd_link_callbacks <emit_ctf>): Likewise.
bfd/
* elf-bfd.h (bfd_section_is_ctf): New inline function.
* elf.c (special_sections_c): Add ".ctf".
(assign_file_positions_for_non_load_sections): Note that
compressed debugging sections etc are not assigned here. Treat
CTF sections like SEC_ELF_COMPRESS sections when is_linker_output:
sh_offset -1.
(assign_file_positions_except_relocs): Likewise.
(find_section_in_list): Note that debugging and CTF sections, as
well as reloc sections, are assigned later.
(_bfd_elf_assign_file_positions_for_non_load): CTF sections get
their size and contents updated.
(_bfd_elf_set_section_contents): Skip CTF sections: unlike
compressed sections, they have no uncompressed content to copy at
this stage.
* elflink.c (elf_link_swap_symbols_out): Call the examine_strtab
callback right before the strtab is written out.
(bfd_elf_final_link): Don't cache the section contents of CTF
sections: they are not populated yet. Call the emit_ctf callback
right at the end, after all the symbols and strings are flushed
out.
ld/
* ldlang.h: (struct lang_input_statement_struct): Add the_ctf.
(struct elf_sym_strtab): Add forward.
(struct elf_strtab_hash): Likewise.
(ldlang_ctf_apply_strsym): Declare.
(ldlang_write_ctf_late): Likewise.
* ldemul.h (ldemul_emit_ctf_early): New.
(ldemul_examine_strtab_for_ctf): Likewise.
(ld_emulation_xfer_type) <emit_ctf_early>: Likewise.
(ld_emulation_xfer_type) <examine_strtab_for_ctf>: Likewise.
* ldemul.c (ldemul_emit_ctf_early): New.
(ldemul_examine_strtab_for_ctf): Likewise.
* ldlang.c: Include ctf-api.h.
(CTF_COMPRESSION_THRESHOLD): New.
(ctf_output): New. Initialized in...
(ldlang_open_ctf): ... this new function. Open all the CTF
sections in the input files: mark them non-loaded and empty
so as not to copy their contents to the output, but linker-created
so the section gets created in the target.
(ldlang_merge_ctf): New, merge types via ctf_link_add_ctf and
ctf_link.
(ldlang_ctf_apply_strsym): New, an examine_strtab callback: wrap
ldemul_examine_strtab_for_ctf.
(lang_write_ctf): New, write out the CTF section.
(ldlang_write_ctf_late): New, late call via bfd's emit_ctf hook.
(lang_process): Call ldlang_open_ctf, ldlang_merge_ctf, and
lang_write_ctf.
* ldmain.c (link_callbacks): Add ldlang_ctf_apply_strsym,
ldlang_write_ctf_late.
* emultempl/aix.em: Add ctf-api.h.
* emultempl/armcoff.em: Likewise.
* emultempl/beos.em: Likewise.
* emultempl/elf.em: Likewise.
* emultempl/generic.em: Likewise.
* emultempl/linux.em: Likewise.
* emultempl/msp430.em: Likewise.
* emultempl/pe.em: Likewise.
* emultempl/pep.em: Likewise.
* emultempl/ticoff.em: Likewise.
* emultempl/vanilla.em: Likewise.
* ldcref.c: Likewise.
* ldctor.c: Likewise.
* ldelf.c: Likewise.
* ldelfgen.c: Likewise.
* ldemul.c: Likewise.
* ldexp.c: Likewise.
* ldfile.c: Likewise.
* ldgram.c: Likewise.
* ldlex.l: Likewise.
* ldmain.c: Likewise.
* ldmisc.c: Likewise.
* ldver.c: Likewise.
* ldwrite.c: Likewise.
* lexsup.c: Likewise.
* mri.c: Likewise.
* pe-dll.c: Likewise.
* plugin.c: Likewise.
* ldelfgen.c (ldelf_emit_ctf_early): New.
(ldelf_examine_strtab_for_ctf): tell libctf about the symtab and
strtab.
(struct ctf_strsym_iter_cb_arg): New, state to do so.
(ldelf_ctf_strtab_iter_cb): New: tell libctf about
each string in the strtab in turn.
(ldelf_ctf_symbols_iter_cb): New, tell libctf
about each symbol in the symtab in turn.
* ldelfgen.h (struct elf_sym_strtab): Add forward.
(struct elf_strtab_hash): Likewise.
(struct ctf_file): Likewise.
(ldelf_emit_ctf_early): Declare.
(ldelf_examine_strtab_for_ctf): Likewise.
* emultempl/elf-generic.em (LDEMUL_EMIT_CTF_EARLY): Set it.
(LDEMUL_EXAMINE_STRTAB_FOR_CTF): Likewise.
* emultempl/aix.em (ld_${EMULATION_NAME}_emulation): Add
emit_ctf_early and examine_strtab_for_ctf, NULL by default.
* emultempl/armcoff.em (ld_${EMULATION_NAME}_emulation): Likewise.
* emultempl/beos.em (ld_${EMULATION_NAME}_emulation): Likewise.
* emultempl/elf.em (ld_${EMULATION_NAME}_emulation): Likewise.
* emultempl/generic.em (ld_${EMULATION_NAME}_emulation): Likewise.
* emultempl/linux.em (ld_${EMULATION_NAME}_emulation): Likewise.
* emultempl/msp430.em (ld_${EMULATION_NAME}_emulation): Likewise.
* emultempl/pe.em (ld_${EMULATION_NAME}_emulation): Likewise.
* emultempl/pep.em (ld_${EMULATION_NAME}_emulation): Likewise.
* emultempl/ticoff.em (ld_${EMULATION_NAME}_emulation): Likewise.
* emultempl/vanilla.em (ld_vanilla_emulation): Likewise.
* Makefile.am: Pull in libctf (and zlib, a transitive requirement
for compressed CTF section emission). Pass it on to DejaGNU.
* configure.ac: Add AM_ZLIB.
* aclocal.m4: Added zlib.m4.
* Makefile.in: Regenerated.
* testsuite/ld-bootstrap/bootstrap.exp: Use it when relinking ld.
This patch, along with previous patches in the series, supports
putting the ELF file header and program headers in a PT_LOAD without
sections.
Logic governing whether headers a loaded has changed a little: The
primary reason to include headers is now the presence of
SIZEOF_HEADERS in a linker script. However, to support scripts that
may have reserved space for headers by hand, we continue to add
headers whenever the first section address is past the end of headers
modulo page size.
include/
* bfdlink.h (struct bfd_link_info): Add load_phdrs field.
bfd/
* elf-nacl.c (nacl_modify_segment_map): Cope with header PT_LOAD
lacking sections.
* elf.c (_bfd_elf_map_sections_to_segments): Assume file and
program headers are required when info->load_phdrs. Reorganize
code handling program headers. Generate a mapping without
sections just for file and program headers when -z separate-code
would indicate they should be on a different page to the first
section.
ld/
* ldexp.c (fold_name <SIZEOF_HEADERS>): Set link_info.load_phdrs.
* testsuite/ld-elf/loadaddr1.d: Pass -z noseparate-code.
* testsuite/ld-elf/loadaddr2.d: Likewise.
* testsuite/ld-i386/vxworks2.sd: Adjust expected output.
* testsuite/ld-powerpc/vxworks2.sd: Likewise.
* testsuite/ld-elf/overlay.d: Remove spu xfail.
* testsuite/ld-spu/ovl.lnk: Don't use SIZEOF_HEADERS.
* testsuite/ld-tic6x/dsbt-be.ld: Likewise.
* testsuite/ld-tic6x/dsbt-inrange.ld: Likewise.
* testsuite/ld-tic6x/dsbt-overflow.ld: Likewise.
* testsuite/ld-tic6x/dsbt.ld: Likewise.
It is usually possible to tell absolute and ordinary symbols apart in
BFD throughout the link, by checking whether the section that owns the
symbol is absolute or not.
That however does not work for ordinary symbols defined in a linker
script outside an output section statement. Initially such symbols are
entered into to the link hash as absolute symbols, owned by the absolute
section. A flag is set in the internal linker expression defining such
symbols to tell the linker to convert them to section-relative ones in
the final phase of the link. That flag is however not accessible to BFD
linker code, including BFD target code in particular.
Add a flag to the link hash then to copy the information held in the
linker expression. Define a macro, `bfd_is_abs_symbol', for BFD code to
use where determining whether a symbol is absolute or ordinary is
required before the final link phase.
This macro will correctly identify the special `__ehdr_start' symbol as
ordinary throughout link, for example, even though early on it will be
assigned to the absolute section. Of course this does not let BFD code
identify what the symbol's ultimate section will be before the final
link phase has converted this symbol (in `update_definedness').
include/
* bfdlink.h (bfd_link_hash_entry): Add `rel_from_abs' member.
bfd/
* linker.c (bfd_is_abs_symbol): New macro.
* bfd-in2.h: Regenerate.
ld/
* ldexp.c (exp_fold_tree_1) <etree_assign, etree_provide>
<etree_provided>: Copy expression's `rel_from_abs' flag to the
link hash.
Andrew Sadek <andrew.sadek.se@gmail.com>
A new implemented feature in GCC Microblaze that allows Position
Independent Code to run using Data Text Relative addressing instead
of using Global Offset Table.
Its aim was to make 'PIC' more efficient and flexible as elf size
excess performance overhead were noticed when using GOT due to the
indirect addressing.
include/ChangeLog:
* bfdlink.h (Add flag): Add new flag @ 'bfd_link_info' struct.
* elf/microblaze.h (Add 3 new relocations):
R_MICROBLAZE_TEXTPCREL_64, R_MICROBLAZE_TEXTREL_64
and R_MICROBLAZE_TEXTREL_32_LO for relax function.
bfd/ChangeLog:
* bfd/reloc.c (2 new BFD relocations):
BFD_RELOC_MICROBLAZE_64_TEXTPCREL &
BFD_RELOC_MICROBLAZE_64_TEXTPCREL
* bfd/bfd-in2.h: Regenerate
* bfd/libbfd.h: Regenerate
* bfd/elf32-microblaze.c (Handle new relocs): define 'HOWTO' of 3
new relocs and handle them in both relocate and relax functions.
(microblaze_elf_reloc_type_lookup): add mapping between for new
bfd relocs.
(microblaze_elf_relocate_section): Handle new relocs in case of
elf relocation.
(microblaze_elf_relax_section): Handle new relocs for elf relaxation.
gas/ChangeLog:
* gas/config/tc-microblaze.c (Handle new relocs directives in
assembler): Handle new relocs from compiler output.
(imm_types): add new imm types for data text relative addressing
TEXT_OFFSET, TEXT_PC_OFFSET
(md_convert_frag): conversion for BFD_RELOC_MICROBLAZE_64_TEXTPCREL,
BFD_RELOC_MICROBLAZE_64_TEXTPCREL
(md_apply_fix): apply fix for BFD_RELOC_MICROBLAZE_64_TEXTPCREL,
BFD_RELOC_MICROBLAZE_64_TEXTPCREL
(md_estimate_size_before_relax): estimate size for
BFD_RELOC_MICROBLAZE_64_TEXTPCREL,
BFD_RELOC_MICROBLAZE_64_TEXTPCREL
(tc_gen_reloc): generate relocations for
BFD_RELOC_MICROBLAZE_64_TEXTPCREL,
BFD_RELOC_MICROBLAZE_64_TEXTPCREL
ld/ChangeLog:
* ld/lexsup.c (Add 2 ld options):
(ld_options): add disable-multiple-abs-defs @ 'ld_options' array
(parse_args): parse new option and pass flag to 'link_info' struct.
* ld/ldlex.h (Add enum): add new enum @ 'option_values' enum.
* ld/ld.texinfo (Add new option): Add description for
'disable-multiple-abs-defs'
* ld/main.c: Initialize flags with false @ 'main'. Handle
disable-multiple-abs-defs @ 'mutiple_definition'.
The new "-z separate-code" option will generate separate code LOAD
segment which must be in wholly disjoint pages from any other data.
include/
PR ld/22393
* bfdlink.h (bfd_link_info): Add separate_code.
ld/
PR ld/22393
* NEWS: Mention "-z separate-code".
* emultempl/elf32.em (gld${EMULATION_NAME}_get_script): Get
builtin linker scripts and return linker scripts from disk for
"-z separate-code".
(gld${EMULATION_NAME}_handle_option): Handle "-z separate-code"
and "-z noseparate-code".
* genscripts.sh: Generate linker scripts for "-z separate-code".
(LD_FLAG): Set to *textonly for "-z separate-code".
* ld.texinfo: Document "-z separate-code".
* lexsup.c (elf_shlib_list_options): Add linker help messsages
for "-z separate-code" and "-z noseparate-code".
* scripttempl/elf.sc (SEPARATE_TEXT): New
(TEXT_SEGMENT_ALIGN): Likewise.
Use ${TEXT_SEGMENT_ALIGN} to align and pad text segment to
${MAXPAGESIZE}.
When --no-define-common is used to build shared library, treat common
symbol as undefined so that common symbols that are referenced from a
shared library to be assigned addresses only in the main program. This
eliminates the unused duplicate space in the shared library, and also
prevents any possible confusion over resolving to the wrong duplicate
when there are many dynamic modules with specialized search paths for
runtime symbol resolution.
--no-define-common is only allowed when building a shared library.
bfd/
PR ld/21903:
* elflink.c (elf_link_add_object_symbols): Treat common symbol
as undefined for --no-define-common.
include/
PR ld/21903:
* bfdlink.h (bfd_link_info): Add inhibit_common_definition.
ld/
PR ld/21903:
* ld.h (command_line): Remove inhibit_common_definition.
* ldgram.y: Replace command_line.inhibit_common_definition with
link_info.inhibit_common_definition.
* ldlang.c (lang_common): Likewise.
* lexsup.c (parse_args): Likewise.
* ldmain.c (main): Only allow --no-define-common with -shared.
* testsuite/ld-elf/pr21903.s: New file.
* testsuite/ld-elf/pr21903a.d: Likewise.
* testsuite/ld-elf/pr21903b.d: Likewise.
* testsuite/ld-elf/pr21903c.d: Likewise.
* testsuite/ld-elf/pr21903d.d: Likewise.
* testsuite/ld-elf/pr21903e.d: Likewise.
To support IBT in Intel Control-flow Enforcement Technology (CET)
instructions:
https://software.intel.com/sites/default/files/managed/4d/2a/control-flow-enforcement-technology-preview.pdf
#define GNU_PROPERTY_X86_FEATURE_1_AND 0xc0000002
#define GNU_PROPERTY_X86_FEATURE_1_IBT (1U << 0)
are added to GNU program properties to indicate that all executable
sections are compatible with IBT when ENDBR instruction starts each
valid target where an indirect branch instruction can land.
GNU_PROPERTY_X86_FEATURE_1_IBT is set on output only if it is set on
all relocatable inputs.
The followings changes are made to the Procedure Linkage Table (PLT):
1. For 64-bit x86-64, PLT is changed to
PLT0: push GOT[1]
bnd jmp *GOT[2]
nop
...
PLTn: endbr64
push namen_reloc_index
bnd jmp PLT0
together with the second PLT section:
PLTn: endbr64
bnd jmp *GOT[namen_index]
nop
BND prefix is also added so that IBT-enabled PLT is compatible with MPX.
2. For 32-bit x86-64 (x32) and i386, PLT is changed to
PLT0: push GOT[1]
jmp *GOT[2]
nop
...
PLTn: endbr64 # endbr32 for i386.
push namen_reloc_index
jmp PLT0
together with the second PLT section:
PLTn: endbr64 # endbr32 for i386.
jmp *GOT[namen_index]
nop
BND prefix isn't used since MPX isn't supported on x32 and BND registers
aren't used in parameter passing on i386.
GOT is an array of addresses. Initially, GOT[namen_index] is filled
with the address of the ENDBR instruction of the corresponding entry
in the first PLT section. The function, namen, is called via the
ENDBR instruction in the second PLT entry. GOT[namen_index] is updated
to the actual address of the function, namen, at run-time.
2 linker command line options are added:
1. -z ibtplt: Generate IBT-enabled PLT.
2. -z ibt: Generate GNU_PROPERTY_X86_FEATURE_1_IBT in GNU program
properties as well as IBT-enabled PLT.
bfd/
* elf32-i386.c (elf_i386_lazy_ibt_plt0_entry): New.
(elf_i386_lazy_ibt_plt_entry): Likewise.
(elf_i386_pic_lazy_ibt_plt0_entry): Likewise.
(elf_i386_non_lazy_ibt_plt_entry): Likewise.
(elf_i386_pic_non_lazy_ibt_plt_entry): Likewise.
(elf_i386_eh_frame_lazy_ibt_plt): Likewise.
(elf_i386_lazy_plt_layout): Likewise.
(elf_i386_non_lazy_plt_layout): Likewise.
(elf_i386_link_hash_entry): Add plt_second.
(elf_i386_link_hash_table): Add plt_second and
plt_second_eh_frame.
(elf_i386_allocate_dynrelocs): Use the second PLT if needed.
(elf_i386_size_dynamic_sections): Use .plt.got unwind info for
the second PLT. Check the second PLT.
(elf_i386_relocate_section): Use the second PLT to resolve
PLT reference if needed.
(elf_i386_finish_dynamic_symbol): Fill and use the second PLT if
needed.
(elf_i386_finish_dynamic_sections): Set sh_entsize on the
second PLT. Generate unwind info for the second PLT.
(elf_i386_plt_type): Add plt_second.
(elf_i386_get_synthetic_symtab): Support the second PLT.
(elf_i386_parse_gnu_properties): Support
GNU_PROPERTY_X86_FEATURE_1_AND.
(elf_i386_merge_gnu_properties): Support
GNU_PROPERTY_X86_FEATURE_1_AND. If info->ibt is set, turn
on GNU_PROPERTY_X86_FEATURE_1_IBT
(elf_i386_link_setup_gnu_properties): If info->ibt is set,
turn on GNU_PROPERTY_X86_FEATURE_1_IBT. Use IBT-enabled PLT
for info->ibtplt, info->ibt or GNU_PROPERTY_X86_FEATURE_1_IBT
is set on all relocatable inputs.
* elf64-x86-64.c (elf_x86_64_lazy_ibt_plt_entry): New.
(elf_x32_lazy_ibt_plt_entry): Likewise.
(elf_x86_64_non_lazy_ibt_plt_entry): Likewise.
(elf_x32_non_lazy_ibt_plt_entry): Likewise.
(elf_x86_64_eh_frame_lazy_ibt_plt): Likewise.
(elf_x32_eh_frame_lazy_ibt_plt): Likewise.
(elf_x86_64_lazy_ibt_plt): Likewise.
(elf_x32_lazy_ibt_plt): Likewise.
(elf_x86_64_non_lazy_ibt_plt): Likewise.
(elf_x32_non_lazy_ibt_plt): Likewise.
(elf_x86_64_get_synthetic_symtab): Support the second PLT.
(elf_x86_64_parse_gnu_properties): Support
GNU_PROPERTY_X86_FEATURE_1_AND.
(elf_x86_64_merge_gnu_properties): Support
GNU_PROPERTY_X86_FEATURE_1_AND. If info->ibt is set, turn
on GNU_PROPERTY_X86_FEATURE_1_IBT
(elf_x86_64_link_setup_gnu_properties): If info->ibt is set,
turn on GNU_PROPERTY_X86_FEATURE_1_IBT. Use IBT-enabled PLT
for info->ibtplt, info->ibt or GNU_PROPERTY_X86_FEATURE_1_IBT
is set on all relocatable inputs.
binutils/
* readelf.c (decode_x86_feature): New.
(print_gnu_property_note): Call decode_x86_feature on
GNU_PROPERTY_X86_FEATURE_1_AND.
* testsuite/binutils-all/i386/empty.d: New file.
* testsuite/binutils-all/i386/empty.s: Likewise.
* testsuite/binutils-all/i386/ibt.d: Likewise.
* testsuite/binutils-all/i386/ibt.s: Likewise.
* testsuite/binutils-all/x86-64/empty-x32.d: Likewise.
* testsuite/binutils-all/x86-64/empty.d: Likewise.
* testsuite/binutils-all/x86-64/empty.s: Likewise.
* testsuite/binutils-all/x86-64/ibt-x32.d: Likewise.
* testsuite/binutils-all/x86-64/ibt.d: Likewise.
* testsuite/binutils-all/x86-64/ibt.s: Likewise.
include/
* bfdlink.h (bfd_link_info): Add ibtplt and ibt.
* elf/common.h (GNU_PROPERTY_X86_FEATURE_1_AND): New.
(GNU_PROPERTY_X86_FEATURE_1_IBT): Likewise.
ld/
* Makefile.am (ELF_X86_DEPS): Add $(srcdir)/emulparams/cet.sh.
* Makefile.in: Regenerated.
* NEWS: Mention GNU_PROPERTY_X86_FEATURE_1_IBT, -z ibtplt
and -z ibt.
* emulparams/cet.sh: New file.
* testsuite/ld-i386/ibt-plt-1.d: Likewise.
* testsuite/ld-i386/ibt-plt-1.s: Likewise.
* testsuite/ld-i386/ibt-plt-2.s: Likewise.
* testsuite/ld-i386/ibt-plt-2a.d: Likewise.
* testsuite/ld-i386/ibt-plt-2b.d: Likewise.
* testsuite/ld-i386/ibt-plt-2c.d: Likewise.
* testsuite/ld-i386/ibt-plt-2d.d: Likewise.
* testsuite/ld-i386/ibt-plt-3.s: Likewise.
* testsuite/ld-i386/ibt-plt-3a.d: Likewise.
* testsuite/ld-i386/ibt-plt-3b.d: Likewise.
* testsuite/ld-i386/ibt-plt-3c.d: Likewise.
* testsuite/ld-i386/ibt-plt-3d.d: Likewise.
* testsuite/ld-i386/plt-main-ibt.dd: Likewise.
* testsuite/ld-i386/plt-pie-ibt.dd: Likewise.
* testsuite/ld-i386/property-x86-empty.s: Likewise.
* testsuite/ld-i386/property-x86-ibt.s: Likewise.
* testsuite/ld-i386/property-x86-ibt1a.d: Likewise.
* testsuite/ld-i386/property-x86-ibt1b.d: Likewise.
* testsuite/ld-i386/property-x86-ibt2.d: Likewise.
* testsuite/ld-i386/property-x86-ibt3a.d: Likewise.
* testsuite/ld-i386/property-x86-ibt3b.d: Likewise.
* testsuite/ld-i386/property-x86-ibt4.d: Likewise.
* testsuite/ld-i386/property-x86-ibt5.d: Likewise.
* testsuite/ld-x86-64/ibt-plt-1-x32.d: Likewise.
* testsuite/ld-x86-64/ibt-plt-1.d: Likewise.
* testsuite/ld-x86-64/ibt-plt-1.s: Likewise.
* testsuite/ld-x86-64/ibt-plt-2.s: Likewise.
* testsuite/ld-x86-64/ibt-plt-2a-x32.d: Likewise.
* testsuite/ld-x86-64/ibt-plt-2a.d: Likewise.
* testsuite/ld-x86-64/ibt-plt-2b-x32.d: Likewise.
* testsuite/ld-x86-64/ibt-plt-2b.d: Likewise.
* testsuite/ld-x86-64/ibt-plt-2c-x32.d: Likewise.
* testsuite/ld-x86-64/ibt-plt-2c.d: Likewise.
* testsuite/ld-x86-64/ibt-plt-2d-x32.d: Likewise.
* testsuite/ld-x86-64/ibt-plt-2d.d: Likewise.
* testsuite/ld-x86-64/ibt-plt-3.s: Likewise.
* testsuite/ld-x86-64/ibt-plt-3a-x32.d: Likewise.
* testsuite/ld-x86-64/ibt-plt-3a.d: Likewise.
* testsuite/ld-x86-64/ibt-plt-3b-x32.d: Likewise.
* testsuite/ld-x86-64/ibt-plt-3b.d: Likewise.
* testsuite/ld-x86-64/ibt-plt-3c-x32.d: Likewise.
* testsuite/ld-x86-64/ibt-plt-3c.d: Likewise.
* testsuite/ld-x86-64/ibt-plt-3d-x32.d: Likewise.
* testsuite/ld-x86-64/ibt-plt-3d.d: Likewise.
* testsuite/ld-x86-64/plt-main-ibt-now.rd: Likewise.
* testsuite/ld-x86-64/plt-main-ibt-x32.dd: Likewise.
* testsuite/ld-x86-64/plt-main-ibt.dd: Likewise.
* testsuite/ld-x86-64/property-x86-empty.s: Likewise.
* testsuite/ld-x86-64/property-x86-ibt.s: Likewise.
* testsuite/ld-x86-64/property-x86-ibt1a-x32.d: Likewise.
* testsuite/ld-x86-64/property-x86-ibt1a.d: Likewise.
* testsuite/ld-x86-64/property-x86-ibt1b-x32.d: Likewise.
* testsuite/ld-x86-64/property-x86-ibt1b.d: Likewise.
* testsuite/ld-x86-64/property-x86-ibt2-x32.d: Likewise.
* testsuite/ld-x86-64/property-x86-ibt2.d: Likewise.
* testsuite/ld-x86-64/property-x86-ibt3a-x32.d: Likewise.
* testsuite/ld-x86-64/property-x86-ibt3a.d: Likewise.
* testsuite/ld-x86-64/property-x86-ibt3b-x32.d: Likewise.
* testsuite/ld-x86-64/property-x86-ibt3b.d: Likewise.
* testsuite/ld-x86-64/property-x86-ibt4-x32.d: Likewise.
* testsuite/ld-x86-64/property-x86-ibt4.d: Likewise.
* testsuite/ld-x86-64/property-x86-ibt5-x32.d: Likewise.
* testsuite/ld-x86-64/property-x86-ibt5.d: Likewise.
* emulparams/elf32_x86_64.sh: Source emulparams/cet.sh.
(TINY_READONLY_SECTION): Add .plt.sec.
* emulparams/elf_i386.sh: Likewise.
* emulparams/elf_x86_64.sh: Source emulparams/cet.sh.
* ld.texinfo: Document -z ibtplt and -z ibt.
* testsuite/ld-i386/i386.exp: Run IBT and IBT PLT tests.
* testsuite/ld-x86-64/x86-64.exp: Likewise.
* testsuite/ld-x86-64/pr21481b.S (check): Updated for x32.
This commit adds a new linker feature: the ability to resolve section
groups as part of a relocatable link.
Currently section groups are automatically resolved when performing a
final link, and are carried through when performing a relocatable link.
By carried through this means that one copy of each section group (from
all the copies that might be found in all the input files) is placed
into the output file. Sections that are part of a section group will
not match input section specifiers within a linker script and are
forcibly kept as separate sections.
There is a slight resemblance between section groups and common
section. Like section groups, common sections are carried through when
performing a relocatable link, and resolved (allocated actual space)
only at final link time.
However, with common sections there is an ability to force the linker to
allocate space for the common sections when performing a relocatable
link, there's currently no such ability for section groups.
This commit adds such a mechanism. This new facility can be accessed in
two ways, first there's a command line switch --force-group-allocation,
second, there's a new linker script command FORCE_GROUP_ALLOCATION. If
one of these is used when performing a relocatable link then the linker
will resolve the section groups as though it were performing a final
link, the section group will be deleted, and the members of the group
will be placed like normal input sections. If there are multiple copies
of the group (from multiple input files) then only one copy of the group
members will be placed, the duplicate copies will be discarded.
Unlike common sections that have the --no-define-common command line
flag, and INHIBIT_COMMON_ALLOCATION linker script command there is no
way to prevent group resolution during a final link, this is because the
ELF gABI specifically prohibits the presence of SHT_GROUP sections in a
fully linked executable. However, the code as written should make
adding such a feature trivial, setting the new resolve_section_groups
flag to false during a final link should work as you'd expect.
bfd/ChangeLog:
* elf.c (_bfd_elf_make_section_from_shdr): Don't initially mark
SEC_GROUP sections as SEC_EXCLUDE.
(bfd_elf_set_group_contents): Replace use of abort with an assert.
(assign_section_numbers): Use resolve_section_groups flag instead
of relocatable link type.
(_bfd_elf_init_private_section_data): Use resolve_section_groups
flag instead of checking the final_link flag for part of the
checks in here. Fix white space as a result.
* elflink.c (elf_link_input_bfd): Use resolve_section_groups flag
instead of relocatable link type.
(bfd_elf_final_link): Likewise.
include/ChangeLog:
* bfdlink.h (struct bfd_link_info): Add new resolve_section_groups
flag.
ld/ChangeLog:
* ld.h (struct args_type): Add force_group_allocation field.
* ldgram.y: Add support for FORCE_GROUP_ALLOCATION.
* ldlex.h: Likewise.
* ldlex.l: Likewise.
* lexsup.c: Likewise.
* ldlang.c (unique_section_p): Check resolve_section_groups flag
not the relaxable link flag.
(lang_add_section): Discard section groups when we're resolving
groups. Clear the SEC_LINK_ONCE flag if we're resolving section
groups.
* ldmain.c (main): Initialise resolve_section_groups flag in
link_info based on command line flags.
* testsuite/ld-elf/group11.d: New file.
* testsuite/ld-elf/group12.d: New file.
* testsuite/ld-elf/group12.ld: New file.
* NEWS: Mention new features.
* ld.texinfo (Options): Document --force-group-allocation.
(Miscellaneous Commands): Document FORCE_GROUP_ALLOCATION.
dynamic_ref_after_ir_def is a little odd compared to other symbol
flags in that as the name suggests, it is set only for certain
references after a definition. It turns out that setting a flag for
any non-ir reference from a dynamic object can be used to solve the
problem for which this flag was invented, which I think is a cleaner.
This patch does that, and sets non_ir_ref only for regular object
references.
include/
* bfdlink.h (struct bfd_link_hash_entry): Update non_ir_ref
comment. Rename dynamic_ref_after_ir_def to non_ir_ref_dynamic.
ld/
* plugin.c (is_visible_from_outside): Use non_ir_ref_dynamic.
(plugin_notice): Set non_ir_ref for references from regular
objects, non_ir_ref_dynamic for references from dynamic objects.
bfd/
* elf64-ppc.c (add_symbol_adjust): Transfer non_ir_ref_dynamic.
* elflink.c (elf_link_add_object_symbols): Update to use
non_ir_ref_dynamic.
(elf_link_input_bfd): Test non_ir_ref_dynamic in addition to
non_ir_ref.
* linker.c (_bfd_generic_link_add_one_symbol): Likewise.
We need to make an IR symbol visible if it is defined in an IR object
and referenced in a dynamic object. When --as-needed is used, since
linker removes the IR symbol reference of the dynamic object if the
dynamic object isn't needed in the first pass, the IR definition isn't
visible to the dynamic object even if the dynamic object becomes needed
in the second pass. Add dynamic_ref_after_ir_def to bfd_link_hash_entry
to track IR symbol which is defined in an IR object and later referenced
in a dynamic object. dynamic_ref_after_ir_def is preserved when restoring
the symbol table for unneeded dynamic object.
bfd/
PR ld/21382
* elflink.c (elf_link_add_object_symbols): Preserve
dynamic_ref_after_ir_def when restoring the symbol table for
unneeded dynamic object.
include/
PR ld/21382
* bfdlink.h (bfd_link_hash_entry): Add dynamic_ref_after_ir_def.
ld/
PR ld/21382
* plugin.c (is_visible_from_outside): Symbol may be visible
from outside if dynamic_ref_after_ir_def is set.
(plugin_notice): Set dynamic_ref_after_ir_def if the symbol is
defined in an IR object and referenced in a dynamic object.
* testsuite/ld-plugin/lto.exp: Run PR ld/21382 tests.
* testsuite/ld-plugin/pr21382a.c: New file.
* testsuite/ld-plugin/pr21382b.c: Likewise.
-z nodynamic-undefined-weak is only implemented for x86. (The sparc
backend has some support code but doesn't enable the option by
including ld/emulparams/dynamic_undefined_weak.sh, and since the
support looks like it may be broken I haven't enabled it.) This patch
adds the complementary -z dynamic-undefined-weak, extends both options
to affect building of shared libraries as well as executables, and
adds support for the option on powerpc.
include/
* bfdlink.h (struct bfd_link_info <dynamic_undefined_weak>):
Revise comment.
bfd/
* elflink.c (_bfd_elf_adjust_dynamic_symbol): Hide undefweak
or make dynamic for info->dynamic_undefined_weak 0 and 1.
* elf32-ppc.c:Formatting.
(ensure_undefweak_dynamic): Don't make dynamic when
info->dynamic_undefined_weak is zero.
(allocate_dynrelocs): Discard undefweak dyn_relocs for
info->dynamic_undefined_weak. Discard undef dyn_relocs when
not default visibility. Discard undef and undefweak
dyn_relocs earlier.
(ppc_elf_relocate_section): Adjust to suit.
* elf64-ppc.c: Formatting.
(ensure_undefweak_dynamic): Don't make dynamic when
info->dynamic_undefined_weak is zero.
(allocate_dynrelocs): Discard undefweak dyn_relocs for
info->dynamic_undefined_weak. Discard them earlier.
ld/
* ld.texinfo (dynamic-undefined-weak): Document.
(nodynamic-undefined-weak): Document that this option now can
be used with shared libs.
* emulparams/dynamic_undefined_weak.sh: Support -z
dynamic-undefined-weak.
* emulparams/elf32ppccommon.sh: Include dynamic_undefined_weak.sh.
* testsuite/ld-undefined/weak-undef.exp (undef_weak_so),
(undef_weak_exe): New. Use them. Add -z dynamic-undefined-weak
and -z nodynamic-undefined-weak tests.
* Makefile.am: Update powerpc dependencies.
* Makefile.in: Regenerate.
include/
* bfdlink.h (struct bfd_link_hash_entry): Add "section" field to
undef. Formatting.
bfd/
* elflink.c (_bfd_elf_is_start_stop): New function.
(_bfd_elf_gc_mark_rsec): Use it.
* elf-bfd.h (_bfd_elf_is_start_stop): Declare.
Delaying checking ELF relocations until opening all input files so
that symbol information is final when relocations are checked. This
is only enabled for x86 targets.
bfd/
* elf-bfd.h (_bfd_elf_link_check_relocs): New.
* elflink.c (_bfd_elf_link_check_relocs): New function.
(elf_link_add_object_symbols): Call _bfd_elf_link_check_relocs
if check_relocs_after_open_input is FALSE.
include/
* bfdlink.h (bfd_link_info): Add check_relocs_after_open_input.
ld/
* emulparams/elf32_x86_64.sh (CHECK_RELOCS_AFTER_OPEN_INPUT):
New.
* emulparams/elf_i386.sh (CHECK_RELOCS_AFTER_OPEN_INPUT):
Likewise.
* emulparams/elf_i386_be.sh (CHECK_RELOCS_AFTER_OPEN_INPUT):
Likewise.
* emulparams/elf_i386_chaos.sh (CHECK_RELOCS_AFTER_OPEN_INPUT):
Likewise.
* emulparams/elf_i386_ldso.sh (CHECK_RELOCS_AFTER_OPEN_INPUT):
Likewise.
* emulparams/elf_i386_vxworks.sh (CHECK_RELOCS_AFTER_OPEN_INPUT):
Likewise.
* emulparams/elf_x86_64.sh (CHECK_RELOCS_AFTER_OPEN_INPUT):
Likewise.
* emulparams/i386nto.sh (CHECK_RELOCS_AFTER_OPEN_INPUT):
Likewise.
* emultempl/elf32.em (gld${EMULATION_NAME}_before_parse):
Set check_relocs_after_open_input to TRUE if
CHECK_RELOCS_AFTER_OPEN_INPUT is yes.
(gld${EMULATION_NAME}_after_open): Call
_bfd_elf_link_check_relocs on all inputs if
check_relocs_after_open_input is TRUE.
This patch adds --compress-debug-sections=[none|zlib|zlib-gnu|zlib-gabi]
to ld for ELF targets to support generating compressed DWARF debug
sections. We always generate .zdebug_* section since section names have
been finalized and they can't be changed easily when compression is
being performed.
bfd/
* bfd-in.h (compressed_debug_section_type): New.
* compress.c (bfd_compress_section_contents): Add an argument
for linker write compression and always generate .zdebug_*
section when linking.
(bfd_init_section_compress_status): Pass FALSE to
bfd_compress_section_contents.
(bfd_compress_section): New function.
* elf.c (elf_fake_sections): For linking, set SEC_ELF_COMPRESS
on DWARF debug sections if COMPRESS_DEBUG is set and rename
section if COMPRESS_DEBUG_GABI_ZLIB isn't set.
(assign_file_positions_for_non_load_sections): Set sh_offset
to -1 if SEC_ELF_COMPRESS is set.
(assign_file_positions_except_relocs): Likwise.
(_bfd_elf_assign_file_positions_for_relocs): Renamed to ...
(_bfd_elf_assign_file_positions_for_non_load): This. Change
return time to bfd_boolean. Compress the section if
SEC_ELF_COMPRESS is set.
(_bfd_elf_write_object_contents): Updated.
(_bfd_elf_set_section_contents): Write section contents to
the buffer if SEC_ELF_COMPRESS is set.
* merge.c: Include "elf-bfd.h".
(sec_merge_emit): Add arguments for contents and offset. Write
to contents with offset if contents isn't NULL.
(_bfd_write_merged_section): Write section contents to the
buffer if SEC_ELF_COMPRESS is set. Pass contents and
output_offset to sec_merge_emit.
* elflink.c (bfd_elf_final_link): Allocate the buffer for
output section contents if SEC_ELF_COMPRESS is set.
* section.c (SEC_ELF_COMPRESS): New.
* bfd-in2.h: Regenerated.
gas/
* as.h (compressed_debug_section_type): Removed.
include/
* bfdlink.h (bfd_link_info): Add compress_debug.
ld/
* ld.texinfo: Document --compress-debug-sections=.
* ldmain.c (main): Set BFD_COMPRESS on output_bfd if
COMPRESS_DEBUG is set. Set BFD_COMPRESS_GABI on output_bfd
for COMPRESS_DEBUG_GABI_ZLIB.
* lexsup.c (elf_static_list_options): Add
--compress-debug-sections=.
* emultempl/elf32.em (OPTION_COMPRESS_DEBUG): New.
(xtra_long): Add "compress-debug-sections".
(gld${EMULATION_NAME}_handle_option): Handle
OPTION_COMPRESS_DEBUG.
ld/testsuite/
* ld-elf/compress.exp (build_tests): Add tests for
--compress-debug-sections=.
(run_tests): Likewise.
Add additonal tests for --compress-debug-sections=.
* ld-elf/gabiend.rt: New file.
* ld-elf/gabinormal.rt: Likewise.
* ld-elf/gnubegin.rS: Likewise.
* ld-elf/gnunormal.rS: Likewise.
* ld-elf/zlibbegin.rS: Likewise.
* ld-elf/zlibnormal.rS: Likewise.
Address of protected data defined in the shared library may be external,
i.e., due to copy relocation. By default, linker backend checks if
relocations against protected data symbols are valid for building shared
library and issues an error if relocation isn't allowed. The new option
override linker backend default. When -z noextern-protected-data is used,
updates on protected data symbols by another module won't be visibile
to the resulting shared library. This option is specific to ELF/i386
and ELF/x86-64.
bfd/
PR ld/pr17709
* elflink.c (_bfd_elf_adjust_dynamic_copy): Check
info->extern_protected_data when warning copy relocs against
protected symbols.
(_bfd_elf_symbol_refs_local_p): Check info->extern_protected_data
when checking protected non-function symbols.
include/
PR ld/pr17709
* bfdlink.h (bfd_link_info): Add extern_protected_data.
ld/
PR ld/pr17709
* ld.texinfo: Document "-z noextern-protected-data".
* ldmain.c (main): Initialize link_info.extern_protected_data
to -1.
* lexsup.c (elf_shlib_list_options): Add
"-z [no]extern-protected-data".
* emulparams/elf32_x86_64.sh: Source extern_protected_data.sh.
* emulparams/elf_i386.sh: Likewise.
* emulparams/elf_i386_be.sh: Likewise.
* emulparams/elf_i386_chaos.sh: Likewise.
* emulparams/elf_i386_ldso.sh: Likewise.
* emulparams/elf_i386_vxworks.sh: Likewise.
* emulparams/elf_k1om.sh: Likewise.
* emulparams/elf_l1om.sh: Likewise.
* emulparams/elf_x86_64.sh: Source extern_protected_data.sh.
(PARSE_AND_LIST_OPTIONS): Renamed to ...
(PARSE_AND_LIST_OPTIONS_BNDPLT): This.
(PARSE_AND_LIST_ARGS_CASE_Z): Renamed to ...
(PARSE_AND_LIST_ARGS_CASE_Z_BNDPLT): This.
(PARSE_AND_LIST_OPTIONS): Append $PARSE_AND_LIST_OPTIONS_BNDPLT.
(PARSE_AND_LIST_ARGS_CASE_Z): Append
$PARSE_AND_LIST_ARGS_CASE_Z_BNDPLT.
* emulparams/extern_protected_data.sh: New file.
ld/testsuite/
PR ld/pr17709
* ld-i386/i386.exp: Run protected6b.
* ld-i386/protected6b.d: New file.
* ld-x86-64/protected6b.d: Likewise.
* ld-x86-64/x86-64.exp: Run protected6b.
LTO output objects have an STT_FILE symbol using the name of the file,
a temporary file. This results in executables that can't be exactly
reproduced, so the file name needs to be dropped. We don't want to
lose all file symbols when linking a mix of lto and non-lto objects as
a file symbol can be used to figure which source file generated a
given local symbol. So lto output objects need to be marked.
I chose to mark lto output objects with a new bfd flag. This flag is
also used to fix a bug in the link-once handling; An object being
loaded after "loading_lto_outputs" is set might be one extracted from
an archive to satisfy new references from lto objects, not an lto
object itself.
The new flag is copied from archive to elements, and the same done
for no_export. This fixes a bug in that --exclude-libs doesn't work
with thin archives. I'm not completely happy with this part of the
patch and may revist this to avoid the hack in
_bfd_look_for_bfd_in_cache.
PR ld/17973
include/
* bfdlink.h (struct bfd_link_info): Delete loading_lto_outputs.
bfd/
* bfd.c (struct bfd): Add lto_output.
* linker.c (_bfd_handle_already_linked): Explicitly test for
objects added by the lto plugin.
* opncls.c (_bfd_new_bfd_contained_in): Copy lto_output and
no_export flags from archive.
* archive.c (open_nested_file): New function, setting lto_output
and no_export, extracted from..
(find_nested_archive): ..here. Flip params. Rename from
_bfd_find_nested_archive.
(_bfd_get_elt_at_filepos): Correct var typo. Use open_nested_file.
(_bfd_look_for_bfd_in_cache): Copy no_export.
* elflink.c (elf_link_add_object_symbols): Remove now unnecessary
my_archive->no_export test.
(elf_link_input_bfd): Drop existing lto_output STT_FILE syms.
Don't use the file name when adding lto_output STT_FILE sym.
* bfd-in2.h: Regenerate.
ld/
* ldlang.h (struct lang_input_statement_flags): Add lto_output.
* ldlang.c (lang_process): Don't set loading_lto_outputs.
* ldfile.c (ldfile_try_open_bfd): Transfer entry flags.lto_output
to bfd.
* plugin.c (add_input_file, add_input_library): Set flags.lto_output.
Trying to use the SEC_LINKER_CREATED section flag to determine whether
a symbol is linker defined fails to work on targets like alpha that
define special SEC_COMMON sections. These might contain symbols that
originated in an object file.
include/
* bfdlink.h (struct bfd_link_hash_entry): Comment non_ir_ref. Add
linker_def.
bfd/
* elflink.c (_bfd_elf_define_linkage_sym): Set linker_def.
* linker.c (_bfd_generic_link_add_one_symbol): Clear linker_def
for CDEF, DEF, DEFW, COM.
ld/
* ldexp.c (exp_fold_tree_1 <etree_provide>): Test linker_def.
ld/testsuite/
* ld-powerpc/sdabase.s,
* ld-powerpc/sdabase.t,
* ld-powerpc/sdabase.d: New test.
* ld-powerpc/sdabase2.t,
* ld-powerpc/sdabase2.d: New test.
* ld-powerpc/powerpc.exp: Run them.
The main aim of this change was to have non_ir_ref set correctly on
new indirect symbols. I could have added a "copy" param to the "notice"
function, so that indirect symbols could be created in plugin_notice,
but it seemed cleaner to create indirect syms earlier and pass them
rather than "string" to "notice".
include/
* bfdlink.h (struct bfd_link_callbacks <notice>): Remove "string"
param, add "inh".
bfd/
* coff-aux.c (coff_m68k_aux_link_add_one_symbol): Only call "notice"
here when not calling the generic add_symbol function. Formatting.
Correct handling of indirect symbols. Update notice call.
* elflink.c (_bfd_elf_notice_as_needed): Update notice call.
* linker.c (_bfd_generic_link_add_one_symbol): Create indirect
symbols early. Update notice call. Add comments regarding weak
symbols vs. indirect.
ld/
* ldmain.c (notice): Update args.
* plugin.c (plugin_notice): Likewise. Follow warning sym link.
Handle new indirect symbol.
Alan Modra
Nick Alcock
H.J. Lu
Maciej W. Rozycki
Michael Eager
Andrew Burgess
fincs
Thomas Preud'homme
Nick Clifton
Rich Felker
Catherine Moore
Igor Zamyatin