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.
Gold supports:
--map-whole-files Map whole files to memory (default on 64-bit hosts)
--no-map-whole-files Map relevant file parts to memory (default on 32-bit hosts)
This patch adds --[no-]map-whole-files command line options for gold
compatibility. They are ignored for ld.
* lexsup.c (ld_options): Add --[no-]map-whole-files for gold
option compatibility.
If plugin didn't claim the file, unmap the buffer.
* plugin.c (plugin_input_file_t): Add use_mmap.
(plugin_pagesize): New.
(get_view): Use plugin_pagesize. Set use_mmap if mmap is used.
(plugin_load_plugins): Initialize plugin_pagesize.
(plugin_maybe_claim): Unmap the buffer if plugin didn't claim the
file.
Offset passed to mmap must be a multiple of the page size. This patch
aligns offset passed to mmap.
* plugin.c (get_view): Align offset passed to mmap.
When plugin isn't active or there is no thing more to claim, we don't
need to call bfd_check_format.
* ldfile.c (ldfile_try_open_bfd): Don't call bfd_check_format
if plugin isn't active or there is no thing more to claim.
There is no need to call bfd_check_format. We should just check format
against bfd_object directly.
* plugin.c (plugin_maybe_claim): Check format against bfd_object
directly.
This patch removes the argument of pointer to struct ld_plugin_input_file.
This is the first step to extract a plugin_object_p out of
plugin_maybe_claim for BFD.
* plugin.c: Include "libbfd.h".
(plugin_strdup): New.
(plugin_maybe_claim): Remove the argument of pointer to struct
ld_plugin_input_file. Open and handle input entry.
* plugin.h (plugin_maybe_claim): Updated.
* ldfile.c (ldfile_try_open_bfd): Call plugin_maybe_claim directly
without passing a pointer to struct ld_plugin_input_file.
* ldmain.c: Don't include "libbfd.h".
(add_archive_element): Call plugin_maybe_claim directly without
passing a pointer to struct ld_plugin_input_file.
This patch uses mmap if it is available and works. It also caches the
view buffer for get_view.
* configure.ac: Add AC_FUNC_MMAP.
* config.in: Regenerated.
* configure: Likewise.
* plugin.c: Include <sys/mman.h>.
(MAP_FAILED): New. Defined if not defined.
(PROT_READ): Likewise.
(MAP_PRIVATE): Likewise.
(view_buffer_t): New.
(plugin_input_file_t): Add view_buffer.
(get_view): Try mmap and cache the view buffer.
(plugin_maybe_claim): Initialize view_buffer.
This patch closes fd only if fd != -1.
* plugin.c (release_input_file): Set fd to -1 after closing it.
(plugin_maybe_claim): Close fd only if fd != -1.
This patchs adds plugin_input_file_t to implement get_input_file, get_view
and release_input_file. The maximum memeory overhead per IR input file
are about 40 bytes for plugin_input_file_t plus the memory to store input
IR filename. According to
http://gcc.gnu.org/wiki/whopr/driver
RELEASE_INPUT_FILE: Function pointer to the linker interface that
releases a file descriptor for a claimed input file. The plug-in library
must call this interface for each file descriptor obtained by the "get
input file" interface. It must release all such file descriptors before
returning from the WPA phase.
However, GCC plug-in library doesn't use the "get input file" interface.
It processed the IR input in the claim file handler. Since the the file
descriptor opened for the IR input was unused after the claim file
handler returns and GCC plug-in library before GCC 5 doesn't call the
RELEASE_INPUT_FILE function pointer, ld closed the file descriptor to
avoid leaking file descriptor. But this approach doesn't work with
other plug-in libraries which uses the "get input file", "get view" and
"release input file" interfaces. To avoid file descriptor leak with
GCC prior to GCC 5 and support other plug-in libraries at the same time,
we close the file descriptor only if the input IR file is a bfd_object
file. This scheme doesn't work when a plug-in library needs the file
descriptor and its IR is stored in bfd_object file.
PR ld/17878
* plugin.c: Include <errno.h>.
(errno): New. Declare if needed.
(plugin_input_file_t): New.
(get_input_file): Implemented.
(get_view): Likewise.
(release_input_file): Likewise.
(add_symbols): Updated.
(get_symbols): Likewise.
(plugin_maybe_claim): Allocate a plugin_input_file_t. Close fd
only for a bfd_object input.
Moving .toc out of .got caused us to lose toc sorting and multi-toc
support.
* emultempl/ppc64elf.em (toc_section_name): New var.
(ppc_after_open): Set it.
(ppc_before_allocation): Use it.
(gld${EMULATION_NAME}_after_allocation): Here too.
The changes to reorder sections for better relro protection on powerpc64,
3e2b0f31, 23283c1b, and 5ad18f16, run into a problem with xlc.
xlc -qdatalocal puts global variables into .toc, which means that .toc
must be writable. The simplest way to accomplish this is to edit the
linker script to remove .toc sections from .got on detecting xlc object
files.
bfd/
* elf64-ppc.h (struct ppc64_elf_params): Add "object_in_toc".
* elf64-ppc.c (ppc64_elf_add_symbol_hook): Assume that global symbols
in .toc indicate xlc compiled code that might require a rw .toc.
ld/
* emulparams/elf64ppc.sh (INITIAL_READWRITE_SECTIONS): Define.
* emultempl/ppc64elf.em (params): Init new field.
(ppc_after_open): New function.
(LDEMUL_AFTER_OPEN): Define.
* ldlang.c (lang_final): Whitespace fix.
ld/testsuite/
* ld-powerpc/tocvar.d, * ld-powerpc/tocvar.s: New test.
* ld-powerpc/tocnovar.d, * ld-powerpc/tocnovar.s: New test.
* ld-powerpc/powerpc.exp: Run tocvar and tocnovar.
This patch fixes PR 4643 by allowing symbols in the LENGTH and ORIGIN
fields of MEMORY regions. Previously, only constants and constant
expressions are allowed.
For the AVR target, this helps define memory constraints more
accurately (per device), without having to create a ton of device
specific linker scripts.
ld/
PR 4643
* ldexp.c (fold_name): Fold LENGTH only after
lang_first_phase_enum.
* ldgram.y (memory_spec): Don't evaluate ORIGIN and LENGTH
rightaway.
* ldlang.h (struct memory_region_struct): Add origin_exp and
length_exp fields.
* ldlang.c (lang_do_memory_regions): New.
(lang_memory_region_lookup): Initialize origin_exp and
length_exp fields.
(lang_process): Call lang_do_memory_regions.
ld/testsuite/
* ld-scripts/memory.t: Define new symbol tred.
* ld-scripts/memory_sym.t: New.
* ld-scripts/script.exp: Perform MEMORY with symbols test, and
conditionally check values of linker symbols.
.toc1 is the second level TOC section used by gcc's -mminimal-toc. It
too should be read-only after relocation. Also, the last patch
description mentioned .sbss moving but didn't actually do that, so fix
that problem. .tocbss (whatever that is) was before .sbss previously,
so move that one too.
* emulparams/elf64ppc.sh (OTHER_SDATA_SECTIONS): Use in place of..
(OTHER_BSS_SYMBOLS): ..this.
(OTHER_PLT_RELOC_SECTIONS): Don't define.
(OTHER_GOT_RELOC_SECTIONS): Add rela.toc1 and rela.tocbss.
(OTHER_READWRITE_SECTIONS): Don't define. Move .toc1 to..
(OTHER_RELRO_SECTIONS_2): ..here.
* scripttempl/elf.sc: Move SBSS too when DATA_SDATA.
When creating a linker mapfile (using -Map=MAPFILE), we previously would
always try to evaluate the expression from a PROVIDE statement.
However, this is not always safe, consider:
PROVIDE (foo = 0x10);
PROVIDE (bar = foo);
In this example, if neither 'foo' or 'bar' is needed, then while
generating the linker mapfile evaluating the expression for 'foo' is
harmless (just the value 0x10). However, evaluating the expression for
'bar' requires the symbol 'foo', which is undefined. This used to cause
a fatal error.
This patch changes the behaviour, so that when the destination of the
PROVIDE is not defined (that is the PROVIDE is not going to provide
anything) the expression is not evaluated, and instead a special string
is displayed to indicate that the linker is discarding the PROVIDE
statement.
This change not only fixes the spurious undefined symbol error, but also
means that a user can now tell if a PROVIDE statement has provided
anything by inspecting the linker mapfile, something that could not be
done before.
ld/ChangeLog:
* ldlang.c (print_assignment): Only evaluate the expression for a
PROVIDE'd assignment when the destination is being defined.
Display a special message for PROVIDE'd symbols that are not being
provided.
ld/testsuite/ChangeLog:
* ld-scripts/provide-4.d: New file.
* ld-scripts/provide-4-map.d: New file.
* ld-scripts/provide-4.t: New file.
* ld-scripts/provide-5.d: New file.
* ld-scripts/provide-5.s: New file.
* ld-scripts/provide-5-map.d: New file.
* ld-scripts/provide-5.t: New file.
* ld-scripts/provide.exp: Run the provide-4.d and provide-5.d
tests.
This moves .got too, which requires .sdata and .sbss to move with it,
because these sections share addressing via the toc pointer and with
small-model code must be within a 16-bit signed offset. .plt, .iplt
and .branch_lt must also be moved since they are addressed via a
32-bit offset from the toc pointer, and we might have a very large
.data section.
This change means we may have some bss style sections before the data
segment, necessitating another PT_LOAD header. Also, since _edata is
defined at the end of the data segment it's possible with an empty
.data to have _edata at the end of .plt which looks a little unusual
since .plt is a bss style section. That should only happen rarely in
real world binaries, but does occur in the ld testsuite.
ld/
* emulparams/elf64ppc.sh (BSS_PLT): Don't define.
(OTHER_READWRITE_SECTIONS): Move .branch_lt to..
(OTHER_RELRO_SECTIONS_2): ..here.
(DATA_GOT, SEPARATE_GOTPLT, DATA_SDATA, DATA_PLT,
PLT_BEFORE_GOT): Define.
* scripttempl/elf.sc: Handle DATA_SDATA and DATA_GOT/DATA_PLT/
PLT_BEFORE_GOT combination.
(DATA_GOT, SDATA_GOT): Don't define if either is already defined.
ld/testsuite/
* ld-powerpc/ambiguousv1.d,
* ld-powerpc/ambiguousv1b.d,
* ld-powerpc/ambiguousv2.d,
* ld-powerpc/ambiguousv2b.d,
* ld-powerpc/elfv2exe.d,
* ld-powerpc/elfv2so.d,
* ld-powerpc/tlsexe.r,
* ld-powerpc/tlsexetoc.r,
* ld-powerpc/tlsso.r,
* ld-powerpc/tlstocso.r: Update.
More sections can be read-only after relocation. .opd is an obvious
candidate.
* emulparams/elf64ppc.sh (OTHER_READWRITE_SECTIONS): Move .opd to..
(OTHER_RELRO_SECTIONS_2): ..here, new define.
* scripttempl/elf.sc: Add OTHER_RELRO_SECTIONS_2.
Running lang_common before garbage collection means slightly less work
in garbage collection code, since common symbols should no longer
appear there. It does have the side effect of keeping linker script
symbols (at least those defined outside of sections) global too,
hence some testsuite churn.
bfd/
PR 17165
* elf-bfd.h (ELF_COMMON_DEF): Note that this might be true for
linker script assignments too.
* elflink.c (elf_gc_sweep_symbol): Don't drop ELF_COMMON_DEF syms.
(bfd_elf_gc_mark_dynamic_ref_symbol): Similarly.
ld/
PR 17165
* ldlang.c (lang_process): Run lang_common before lang_gc_sections.
ld/testsuite/
* ld-gc/pr14265.d,
* ld-cris/tls-gc-68.d,
* ld-cris/tls-gc-69.d,
* ld-cris/tls-gc-70.d,
* ld-cris/tls-gc-71.d,
* ld-cris/tls-gc-75.d,
* ld-cris/tls-gc-76.d,
* ld-cris/tls-gc-79.d,
* ld-mmix/bpo-10.d,
* ld-mmix/bpo-11.d: Update.
If no object files have .eh_frame, but some shared library does, then
ld creates a .eh_frame_hdr section using the shared library bfd. This
is silly since shared library .eh_frame sections don't contribute to
the output .eh_frame and thus no .eh_frame_hdr is needed.
Also, the bfd section list and count is cleared for shared libraries,
and a zero section count used as a flag in lang_check to omit a call
to bfd_merge_private_bfd_data for shared libraries. If we create a
section on a shared lib bfd then ld will wrongly attempt to merge the
shared library private bfd data.
PR 17742
* ld/emultempl/elf32.em (gld${EMULATION_NAME}_after_open): Exclude
shared libraries in loop looking for .eh_frame sections.
Similarly for build-id loop.
The AVR target has an elf header flag to indicate if an object was
assembler ready for linker relaxation. If a partial link is performed
then it is important that the link-relax flag in the output object is
set correctly, otherwise, during the final link, we might try to perform
linker relaxation on code that was not assembled suitably.
As the link-relax elf header covers the entire object file we must be
conservative when setting the flag in the output object, so, for a
partial link, any input object that does not have the link-relax flag
set will cause the output object to also not have the link-relax flag
set.
This conservative approach could be softened in future, we only need to
disable the link relax flag if an input file is not marked link-relax
ready, and the input file contains a relaxable section. However, I've
left this optimisation for a later day.
For the final link I've overloaded the use of the link-relax elf header
flag, in a final executable, the flag now indicates if the executable
was built with linker relaxation on or not.
ld/ChangeLog:
* emultempl/avrelf.em: Add include of elf/avr.h.
(avr_finish): New function.
(LDEMUL_FINISH): Added.
ld/testsuite/ChangeLog:
* ld-avr/relax-elf-flags-01.d: New file.
* ld-avr/relax-elf-flags-02.d: New file.
* ld-avr/relax-elf-flags-03.d: New file.
* ld-avr/relax-elf-flags-04.d: New file.
* ld-avr/relax-elf-flags-05.d: New file.
* ld-avr/relax-elf-flags-06.d: New file.
* ld-avr/relax-elf-flags-07.d: New file.
* ld-avr/relax-elf-flags-08.d: New file.
* ld-avr/relax-elf-flags-a.s: New file.
* ld-avr/relax-elf-flags-b.s: New file.
or maybe not just yet, but this is better than a FIXME.
* ldexp.c (update_definedness): Return false if script symbol is
redefining a strong symbol in an object.
(exp_fold_tree_1 <etree_assign>): Set up for reporting a multiple
definition error, but for now leave disabled.
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 old code missed testing bfd_link_hash_undefweak, and wrongly
excluded bfd_link_hash_common symbols. It is also clearer to invert
the set of enum bfd_link_hash_type values tested.
bfd_link_hash_indirect and bfd_link_hash_warning will never appear
here.
* ldexp.c (update_definedness): Correct logic setting by_object.
This moves support code for DEFINED to ldexp.c where it is used,
losing the lang_ prefix on identifiers. Two new functions are needed
to initialize and clean up to hash table, but other than that there
are no functional changes here.
* ldexp.c (struct definedness_hash_entry, definedness_table)
(definedness_newfunc, symbol_defined, update_definedness): Move
and rename from..
* ldlang.h (struct lang_definedness_hash_entry): ..here,..
* ldlang.c (lang_definedness_table, lang_definedness_newfunc)
(lang_symbol_defined, lang_update_definedness): ..and here.
* ldexp.c (ldexp_init, ldexp_finish): New functions, extracted from..
* ldlang.c (lang_init, lang_finish): ..here.
* ldexp.h (ldexp_init, ldexp_finish): Declare.
* ldlang.h (lang_symbol_defined, lang_update_definedness): Delete.
* ldmain.c (main): Call ldexp_init and ldexp_finish.
When there are both PLT and GOT references to the same function symbol,
linker will create a GOTPLT slot for PLT entry and a GOT slot for GOT
reference. A run-time JUMP_SLOT relocation is created to update the
GOTPLT slot and a run-time GLOB_DAT relocation is created to update the
GOT slot. Both JUMP_SLOT and GLOB_DAT relocations will apply the same
symbol value to GOTPLT and GOT slots, respectively, at run-time.
This optimization combines GOTPLT and GOT slots into a single GOT slot
and removes the run-time JUMP_SLOT relocation. It replaces the regular
PLT entry:
indirect jump [GOTPLT slot]
push relocation index
jump PLT0
with an GOT PLT entry with an indirect jump via the GOT slot:
indirect jump [GOT slot]
nop
and resolves PLT reference to the GOT PLT entry.
We must avoid this optimization if pointer equality is needed since
we don't clear symbol value in this case and the dynamic linker won't
update the GOT slot. Otherwise, the resulting binary will get into an
infinite loop at run-time.
bfd/
* elf32-i386.c (elf_i386_got_plt_entry): New.
(elf_i386_pic_got_plt_entry): Likewise.
(elf_i386_link_hash_entry): Add plt_got.
(elf_i386_link_hash_table): Likewise.
(elf_i386_link_hash_newfunc): Initialize plt_got.offset to -1.
(elf_i386_get_local_sym_hash): Likewise.
(elf_i386_check_relocs): Create the GOT PLT if there are both
PLT and GOT references when the regular PLT is used.
(elf_i386_allocate_dynrelocs): Use the GOT PLT if there are
both PLT and GOT references unless pointer equality is needed.
(elf_i386_relocate_section): Also check the GOT PLT when
resolving R_386_PLT32.
(elf_i386_finish_dynamic_symbol): Use the GOT PLT if it is
available.
* elf64-x86-64.c (elf_x86_64_link_hash_entry): Add plt_got.
(elf_x86_64_link_hash_table): Likewise.
(elf_x86_64_link_hash_newfunc): Initialize plt_got.offset to -1.
(elf_x86_64_get_local_sym_hash): Likewise.
(elf_x86_64_check_relocs): Create the GOT PLT if there are both
PLT and GOT references when the regular PLT is used.
(elf_x86_64_allocate_dynrelocs): Use the GOT PLT if there are
both PLT and GOT references unless pointer equality is needed.
(elf_x86_64_relocate_section): Also check the GOT PLT when
resolving R_X86_64_PLT32.
(elf_x86_64_finish_dynamic_symbol): Use the GOT PLT if it is
available.
ld/
* emulparams/elf_i386.sh (TINY_READONLY_SECTION): New.
* emulparams/elf_x86_64.sh (TINY_READONLY_SECTION): Add .plt.got.
ld/testsuite/
* ld-i386/i386.exp: Add run-time relocation tests for plt-main.
* ld-i386/plt-main.rd: New file.
* ld-x86-64/plt-main-bnd.dd: Likewise.
* ld-x86-64/plt-main.rd: Likewise.
* ld-x86-64/x86-64.exp: Add run-time relocation tests for
plt-main.
Alignment of plt stubs was broken, firstly because the option was
being dropped due to the alignment value not being set in the "params"
struct used in elf64-ppc.c, and secondly due to not calculating the
number of alignment boundary crossings correctly.
bfd/
* elf64-ppc.c (plt_stub_pad): Correct.
ld/
* ld.texinfo: Correct --plt-align documentation.
* emultempl/ppc64elf.em (plt_stub_align): Delete. Use and set
params.plt_stub_align instead.
H.J. Lu
Alan Modra
Senthil Kumar Selvaraj
Andrew Burgess
Jiong Wang
Eric Botcazou
Igor Zamyatin
Denis Chertykov