1) _SDA_BASE_ and _SDA2_BASE_ and defined automatically, in a similar
manner to the way _GLOBAL_OFFSET_TABLE_ is handled. It's a little
more complicated to remove the symbols because _SDA_BASE_ needs to
be there if either .sdata or .sbss is present, and similarly for
_SDA2_BASE.
2) The linker created .sdata and .sdata2 sections used for
R_PPC_EMB_SDAI16 and R_PPC_EMB_SDA2I16 pointers are created early.
Nowadays we strip unneeded sections from the output, so it isn't
necessary to delay creating the sections.
3) The output section for targets of various SDA relocs is now checked
as per the ABI(s). We previously allowed .sdata.foo and similar,
most likely because at some stage we were checking input sections.
Also, the patch fixes a long-standing bug in size_input_sections
that affects the values of symbols defined in stripped input
sections.
PR 16952
bfd/
* elf32-ppc.c (ppc_elf_create_linker_section): Move earlier.
Remove redundant setting of htab->elf.dynobj. Don't align.
Define .sdata symbols using _bfd_elf_define_linkage_sym.
(ppc_elf_create_glink): Call ppc_elf_create_linker_section.
(create_sdata_sym): Delete.
(elf_allocate_pointer_linker_section): Rename from
elf_create_pointer_linker_section. Align section.
(ppc_elf_check_relocs): Don't call ppc_elf_creat_linker_section
directly here, or create_sdata_sym. Set ref_regular on _SDA_BASE_
and _SDA2_BASE_.
(ppc_elf_size_dynamic_sections): Remove ATTRIBUTE_UNUSED on param.
Remove unnecessary tests on _SDA_BASE_ sym.
(maybe_strip_sdasym, ppc_elf_maybe_strip_sdata_syms): New functions.
(ppc_elf_relocate_section): Tighten SDA reloc symbol section checks.
* elf32-ppc.h (ppc_elf_set_sdata_syms): Delete.
(ppc_elf_maybe_strip_sdata_syms): Declare.
ld/
* emulparams/elf32ppccommon.sh (_SDA_BASE_, _SDA2_BASE_): Delete.
* emultempl/ppc32elf.em (ppc_before_allocation): Call
ppc_elf_maybe_strip_sdata_syms.
* ldlang.c (size_input_section): Correct output_offset value
for excluded input sections.
ld:
* ldlang.c (lang_finish): Don't call bfd_link_hash_table_free here.
(output_bfd_hash_table_free_fn): New variable.
(open_output): Save the _bfd_link_hash_table_free function for the
output_bfd into output_bfd_hash_table_free_fn.
* ldmain.c (ld_cleanup): If set, call output_bfd_hash_table_free_fn
on link_info.hash.
* ldlang.h (output_bfd_hash_table_free_fn): Declare.
ld/testsuite:
* ld-mmix/wrap1.d, ld-mmix/wrap1a.s, ld-mmix/wrap1b.s,
ld-mmix/wrap1c.s, ld-mmix/wrap2.d, ld-mmix/wrap3.d,
ld-mmix/wrap3a.s, ld-mmix/wrap3b.s, ld-mmix/wrap4.d: New
tests.
ld/
* emultempl/alphaelf.em (alpha_after_parse): Enable 2 relax passes.
bfd/
* elf64-alpha.c (elf64_alpha_size_got_sections): New may_merge
parameter; honor it and disable got merging when false.
(elf64_alpha_relax_got_load): Do not relax to GPREL relocs during
the first pass of relaxation.
(elf64_alpha_relax_with_lituse): Likewise. Move relaxed relocs to
the end of the LITERAL+LITUSE chain.
(elf64_alpha_relax_section): Only process LITERAL relocs during the
second pass of relaxation.
I got the ppc476 workaround wrong. bctr (and bctrl) as the last
instruction in a page can hit the icache bug if the preceding mtctr
insn is close by, and the destination is in the first few instructions
on the next page. This scenario can occur with code generated by gcc
to implement switch statements, or in code generated to call by
function pointer.
To prevent the bctr problem it is also necessary to remove other
instructions that otherwise would be safe.
bfd/
* elf32-ppc.c (ppc_elf_relocate_section): Remove bctr from list
of safe ppc476 insns at end of page. Also remove non-branch insns.
Expand comments.
ld/
* emultempl/ppc32elf.em (no_zero_padding, ppc_finish): New functions.
(LDEMUL_FINISH): Define.
the Cygwin and MinGW targets. The manifest is now going to be handled by gcc.
* scripttempl/pe.sc (R_RSRC): Remove default manifest.
* scripttempl/pep.sc (R_RSRC): Remove default manifest.
The linker script documentation does not mention the optional comma
that may follow an output section command or an overlay command.
In some cases, where a fill expression is used, and the next
output section command begins with an operator (e.g., "/DISCARD/"),
the comma may be required to separate the two commands.
Currently, GNU ld doesn't require the comma, but gold does.
ld/
PR gold/16804
* ld.texinfo: Document optional comma following output section
command and overlay command.
When aligning input sections, we are supposed to take the fill pattern
from a FILL statement, if there is one in the output section statement.
ld/
* ldlang.c (lang_size_sections_1 <lang_input_section_enum>): Use
current "fill", not "output_section_statement->fill".
ld/testsuite/
* ld-scripts/fill.d, * ld-scripts/fill.t, * ld-scripts/fill_0.s,
* ld-scripts/fill_1.s, * ld-scripts/fill_2.s: New test.
* ld-scripts/data.exp: Run it.
would not honour the [no]execstack. Fully linked binaries use a special segment to indicate the
state of the stack, but relocatable object files only have sections, and .note.GNU-stack was not
being created.
* emultempl/elf32.em (_after_open): Create a .note.GNU-stack
section when performing a relocatable link with -z [no]execstack
specified.
This patch scans all input files for symbol reference warning if the
symbol reference doesn't exist in the current input file.
ld/
PR ld/16756
* ldmain.c (symbol_warning): New function.
(warning_callback): Use it. Scan all input files for a reference
to SYMBOL.
ld/testsuite/
PR ld/16756
* ld-plugin/lto.exp: Expect filename and line number for PR
ld/12760 test.
should work for all types of input .rsrc section.
* peXXigen.c (rsrc_process_section): Add code to scan input
sections and record their lengths. Use these lengths to find the
start of each merged .rsrc section.
* scripttempl/pe.sc (R_RSRC): Fix default-manifest exclusion.
(.rsrc): Add SUBALIGN(4). Remove SORT.
* scripttempl/pep.sc: Likewise.
For libraries without a soname, -l:libfoo.so set DT_NEEDED to the search
dir plus filename, while gold and -lfoo just use the filename. This
patch fixes the inconsistency.
* ldlang.h (full_name_provided): New input flag.
* ldlang.c (new_afile): Don't use lang_input_file_is_search_file_enum
for -l:namespec. Instead use lang_input_file_is_l_enum with
full_name_provided flag.
* ldlfile.c (ldfile_open_file_search): Don't complete lib name if
full_name_provided flag is set.
* emultempl/elf32.em (gld${EMULATION_NAME}_open_dynamic_archive):
Handle full_name_provided libraries. Tidy EXTRA_SHLIB_EXTENSION
support. Set DT_NEEDED for -l:namespec as namespec.
* emultempl/aix.em (ppc_after_open_output): Handle full_name_provided.
* emultempl/linux.em (gld${EMULATION_NAME}_open_dynamic_archive):
Don't handle full_name_provided libraries.
* emultempl/pe.em (gld${EMULATION_NAME}_open_dynamic_archive): Ditto.
* emultempl/pep.em (gld${EMULATION_NAME}_open_dynamic_archive): Ditto.
* emultempl/vms.em (gld${EMULATION_NAME}_open_dynamic_archive): Ditto.
built when constructing a toolchain configued from all targets.
* Makefile.am (ALL_EMUL_EXTRA_BINARIES): Remove default-manifest.
* Makefile.in: Regenerate.
Enabled via the use of a new linker command line option: --long-plt.
* bfd-in.h: Add export of bfd_elf32_arm_use_long_plt.
* bfd-in2.h: Regenerate.
* elf32-arm.c (elf32_arm_plt_entry_long): New array.
(elf32_arm_link_hash_table_create): Set plt_entry_size to 16 if
using long PLT entries.
(bfd_elf32_arm_use_long_plt): New function.
(elf32_arm_populate_plt_entry): Add support for long PLT entries.
* emultempl/armelf.em (OPTION_LONG_PLT): Define.
(PARSE_AND_LIST_LONGOPTS): Add long-plt.
(PARSE_AND_LIST_OPTIONS): Likewise.
(PARSE_AND_LIST_ARGS_CASES): Handle long-plt.
* ld.texinfo: Document --long-plt.
* ld-arm/long-plt-format.s: New test case.
* ld-arm/long-plt-format.d: Expected disassembly.
* ld-arm/arm-elf.exp: Run the new test.
The manifest is necessary in order for the linked binaries to be executed in a Windows 8 environment.
The manifest is added using a linker script so that this feature will be compiler-neutral. The resource
merging code in the linker means that if an application provides its own manifest then the default
manifest will be ignored.
* configure.in (all_emul_extra_binaries): New variable. Populated
by invoking configure.tgt.
(EMUL_EXTRA_BINARIES): New substitution.
* configure: Regenerate.
* configure.tgt (target_extra_binaries): New variable. Set to
default-manifest.o for Cygwin and MinGW targets.
* Makefile.am (EMUL_EXTRA_BINARIES): New variable. Initialised
by the configure script.
(ALL_EMUL_EXTRA_BINARIES): New variable.
(default-manifest.o): New rule to build the default manifest.
(ld_new_DEPENDENCIES): Add EMUL_EXTRA_BINARIES.
(install-data-local): Add EMUL_EXTRA_BINARIES.
* Makefile.in: Regenerate.
* ld.texinfo: Document default manifest support.
* emulparams/i386pe.sh (DEFAULT_MANIFEST): Define.
* emulparams/i386pep.sh (DEFAULT_MANIFEST): Define.
* emultempl/default-manifest.rc: New file.
* scripttempl/pe.sc (R_RSRC): Include DEFAULT_MANIFEST, if defined.
* scripttempl/pep.sc (R_RSRC): Likewise.
* ld-pe/longsecn-1.d: Allow for extra sections.
* ld-pe/longsecn-2.d: Likewise.
* ld-pe/longsecn.d: Likewise.
* ld-pe/secrel.d: Likewise.
5446cbdf82 broke powerpc-lynxos,
powerpc-netware, powerpc-windiss and powerpc-vxworks.
bfd/
* elf32-ppc.c (ppc_elf_link_hash_table_create): Provide default
params for targets that don't use ppc32elf.em.
ld/
* emulparams/elf32ppcvxworks.sh: Source plt_unwind.sh and
use ppc32elf.em.
* emultempl/ppc32elf.em (ppc_after_open): Don't compile for
vxworks.
(LDEMUL_AFTER_OPEN): Don't set for vxworks.
(PARSE_AND_LIST_LONGOPTS, PARSE_AND_LIST_OPTIONS): Exclude
-secure-plt, -bss-plt and -sdata-got when vxworks.
Intel MPX introduces 4 bound registers, which will be used for parameter
passing in x86-64. Bound registers are cleared by branch instructions.
Branch instructions with BND prefix will keep bound register contents.
This leads to 2 requirements to 64-bit MPX run-time:
1. Dynamic linker (ld.so) should save and restore bound registers during
symbol lookup.
2. Change the current 16-byte PLT0:
ff 35 08 00 00 00 pushq GOT+8(%rip)
ff 25 00 10 00 jmpq *GOT+16(%rip)
0f 1f 40 00 nopl 0x0(%rax)
and 16-byte PLT1:
ff 25 00 00 00 00 jmpq *name@GOTPCREL(%rip)
68 00 00 00 00 pushq $index
e9 00 00 00 00 jmpq PLT0
which clear bound registers, to preserve bound registers.
We use 2 new relocations:
to mark branch instructions with BND prefix.
When linker sees any R_X86_64_PC32_BND or R_X86_64_PLT32_BND relocations,
it switches to a different PLT0:
ff 35 08 00 00 00 pushq GOT+8(%rip)
f2 ff 25 00 10 00 bnd jmpq *GOT+16(%rip)
0f 1f 00 nopl (%rax)
to preserve bound registers for symbol lookup and it also creates an
external PLT section, .pl.bnd. Linker will create a BND PLT1 entry
in .plt:
68 00 00 00 00 pushq $index
f2 e9 00 00 00 00 bnd jmpq PLT0
0f 1f 44 00 00 nopl 0(%rax,%rax,1)
and a 8-byte BND PLT entry in .plt.bnd:
f2 ff 25 00 00 00 00 bnd jmpq *name@GOTPCREL(%rip)
90 nop
Otherwise, linker will create a legacy PLT1 entry in .plt:
68 00 00 00 00 pushq $index
e9 00 00 00 00 jmpq PLT0
66 0f 1f 44 00 00 nopw 0(%rax,%rax,1)
and a 8-byte legacy PLT in .plt.bnd:
ff 25 00 00 00 00 jmpq *name@GOTPCREL(%rip)
66 90 xchg %ax,%ax
The initial value of the GOT entry for "name" will be set to the the
"pushq" instruction in the corresponding entry in .plt. Linker will
resolve reference of symbol "name" to the entry in the second PLT,
.plt.bnd.
Prelink stores the offset of pushq of PLT1 (plt_base + 0x10) in GOT[1]
and GOT[1] is stored in GOT[3]. We can undo prelink in GOT by computing
the corresponding the pushq offset with
GOT[1] + (GOT offset - &GOT[3]) * 2
Since for each entry in .plt except for PLT0 we create a 8-byte entry in
.plt.bnd, there is extra 8-byte per PLT symbol.
We also investigated the 16-byte entry for .plt.bnd. We compared the
8-byte entry vs the the 16-byte entry for .plt.bnd on Sandy Bridge.
There are no performance differences in SPEC CPU 2000/2006 as well as
micro benchmarks.
Pros:
No change to undo prelink in dynamic linker.
Only 8-byte memory overhead for each PLT symbol.
Cons:
Extra .plt.bnd section is needed.
Extra 8 byte for legacy branches to PLT.
GDB is unware of the new layout of .plt and .plt.bnd.
bfd/
* elf64-x86-64.c (elf_x86_64_bnd_plt0_entry): New.
(elf_x86_64_legacy_plt_entry): Likewise.
(elf_x86_64_bnd_plt_entry): Likewise.
(elf_x86_64_legacy_plt2_entry): Likewise.
(elf_x86_64_bnd_plt2_entry): Likewise.
(elf_x86_64_bnd_arch_bed): Likewise.
(elf_x86_64_link_hash_entry): Add has_bnd_reloc and plt_bnd.
(elf_x86_64_link_hash_table): Add plt_bnd.
(elf_x86_64_link_hash_newfunc): Initialize has_bnd_reloc and
plt_bnd.
(elf_x86_64_copy_indirect_symbol): Also copy has_bnd_reloc.
(elf_x86_64_check_relocs): Create the second PLT for Intel MPX
in 64-bit mode.
(elf_x86_64_allocate_dynrelocs): Handle the second PLT for IFUNC
symbols. Resolve call to the second PLT if it is created.
(elf_x86_64_size_dynamic_sections): Keep the second PLT section.
(elf_x86_64_relocate_section): Resolve PLT references to the
second PLT if it is created.
(elf_x86_64_finish_dynamic_symbol): Use BND PLT0 and fill the
second PLT entry for BND relocation.
(elf_x86_64_finish_dynamic_sections): Use MPX backend data if
the second PLT is created.
(elf_x86_64_get_synthetic_symtab): New.
(bfd_elf64_get_synthetic_symtab): Likewise. Undefine for NaCl.
ld/
* emulparams/elf_x86_64.sh (TINY_READONLY_SECTION): New.
ld/testsuite/
* ld-x86-64/mpx.exp: Run bnd-ifunc-1 and bnd-plt-1.
* ld-x86-64/bnd-ifunc-1.d: New file.
* ld-x86-64/bnd-ifunc-1.s: Likewise.
* ld-x86-64/bnd-plt-1.d: Likewise.
This patch allows the user to override powerpc64-ld's default for
providing linker generated register save and restore functions as used
by gcc -Os code. Normally these are not provided by ld -r, so Linux
kernel modules have needed to include their own copies.
bfd/
* elf64-ppc.h (struct ppc64_elf_params): Add save_restore_funcs.
* elf64-ppc.c (ppc64_elf_func_desc_adjust): Use it to control
provision of out-of-line register save/restore routines.
ld/
* emultempl/ppc64elf.em (params): Init new field.
(ppc_create_output_section_statements): Set params.save_restore_funcs
default.
(PARSE_AND_LIST_*): Add support for --save-restore-funcs and
--no-save-restore-funcs.
Moves assorted variables used to communicate between ld and bfd into
a struct, hooks it into the bfd link_hash_table early, and removes
all other places where such variables were passed piecemeal.
bfd/
* elf64-ppc.h (struct ppc64_elf_params): Define.
(ppc64_elf_init_stub_bfd, ppc64_elf_edit_opd, ppc64_elf_tls_setup,
ppc64_elf_setup_section_lists, ppc64_elf_size_stubs,
ppc64_elf_build_stubs): Update prototype.
* elf64-ppp.c (struct ppc_link_hash_table): Add params, delete other
fields now in params. Adjust code throughout file.
(ppc64_elf_init_stub_bfd): Delete "abfd" parameter, add "params".
Save params pointer in htab.
(ppc64_elf_edit_opd, ppc64_elf_tls_setup,
ppc64_elf_setup_section_lists, ppc64_elf_size_stubs,
ppc64_elf_build_stubs): Remove parameters now in "params".
ld/
* emultemps/ppc64elf.em (params): New static struct replacing
various other static vars. Adjust code throughout file.
This fixes the glaring error that the ppc476 workaround wasn't
actually enabled for ld -r, and adjusts relocations to match moved
code.
bfd/
* elf32-ppc.c (ppc_elf_relocate_section): Move relocs on insns
patched for ppc476 workaround. Reapply branch taken/not taken
relocs.
ld/
* emultempl/ppc32elf.em (ppc_after_open_output): Really enable
ppc476 workaround for ld -r.
The Linux kernel builds modules using ld -r. These might need the
ppc476 workaround, so enable it for ld -r if sections have sufficient
alignment to tell location within a page.
bfd/
* elf32-ppc.c (ppc_elf_relax_section): Enable ppc476 workaround
for ld -r, when code sections are sufficiently aligned.
* elf32-ppc.h (struct ppc_elf_params): Delete pagesize. Add
pagesize_p2.
ld/
* emultempl/ppc32elf.em (pagesize): New static var.
(ppc_after_open_output): Set params.pagesize_p2 from pagesize.
(PARSE_AND_LIST_ARGS_CASES): Adjust to use pagesize.
This implements a work-around for an icache bug on 476 that can cause
execution of stale instructions when control falls through from one
page to the next. The idea is to prevent such fall-through by
replacing the last instruction on a page with a branch to a patch
area containing the instruction, then branch to the next page.
The patch also fixes a number of bugs in the existing support for long
branch trampolines.
bfd/
* elf32-ppc.c (struct ppc_elf_link_hash_table): Add params.
Delete emit_stub_syms, no_tls_get_addr_opt. Update all uses.
(ppc_elf_link_params): New function.
(ppc_elf_create_glink): Align .glink to 64 bytes for ppc476
workaround.
(ppc_elf_select_plt_layout): Remove plt_style and emit_stub_syms
parameters. Use htab->params instead.
(ppc_elf_tls_setup): Remove no_tls_get_addr_opt parameter.
(ppc_elf_size_dynamic_sections): Align __glink_PLTresolve to
64 bytes for ppc476 workaround.
(struct ppc_elf_relax_info): New.
(ppc_elf_relax_section): Exclude linker created sections and
those too small to hold one instruction. Don't add another
branch around trampolines on later relax passes. Don't
generate trampolines for undefined symbols when !relocatable,
nor for plugin symbols. Allocate space for ppc476 workaround
patch area. Free fixups on error return path.
(ppc_elf_relocate_section): Handle ppc476 workaround patching.
* elf32-ppc.h (struct ppc_elf_params): New.
(ppc_elf_select_plt_layout, ppc_elf_tls_setup): Update prototype.
(ppc_elf_link_params): Declare.
* section.c (SEC_INFO_TYPE_TARGET): Define.
* bfd-in2.h: Regenerate.
ld/
* emultempl/ppc32elf.em (no_tls_get_addr_opt, emit_stub_syms)
plt_style): Delete. Adjust all refs to instead use..
(params): ..this. New variable.
(ppc_after_open_output): New function. Tweak params and pass to
ppc_elf_link_params.
(ppc_after_open): Adjust ppc_elf_select_plt_layout call.
(ppc_before_allocation): Adjust ppc_elf_tls_setup call. Enable
relaxation for ppc476 workaround.
(PARSE_AND_LIST_*): Add --{no-,}ppc476-workaround support.
(LDEMUL_CREATE_OUTPUT_SECTION_STATEMENTS): Define.
Since all MCUs now have their own specific linker script (courtesy of
TI) there is no need for these emulations and so this patch removes
them.
* Makefile.am: Remove obsolete MSP430 emulations.
* configure.tgt: Likewise.
* emulparams/msp430all.sh: Likewise.
* Makefile.in: Regenerate.
Ensures TLS orphans are placed adjacent to existing TLS sections,
and fixes places where the output_section_statement flags (which might
not be set) were tested when bfd_section flags were available.
* ldlang.c (lang_output_section_find_by_flags): Be careful to
test look->bfd_section->flags if available rather than
look->flags. Separate SEC_THREAD_LOCAL handling from
SEC_READONLY loop, and rewrite.
Adds a section for --as-needed libraries to a linker map file, similar
to what we do for archive libraries.
bfd/
* elflink.c (elf_link_add_object_symbols): Call minfo for --as-needed.
ld/
* ldlang.c (asneeded_list_head, asneeded_list_tail): New vars.
(lang_init): Initialise them.
(lang_print_asneeded): New function.
(lang_process): Call lang_print_asneeded.
* ldlang.h (struct asneeded_minfo): New.
(asneeded_list_tail): Declare.
* ldmain.c (add_archive_element): Improve archive map heading.
* ldmisc.c (minfo): Stash --as-needed info.
An assignment to dot in an output section that allocates space of
course keeps the output section. Here, I'm changing the behaviour for
assignments that don't allocate space. The idea is not so much to
allow people to force output of an empty section with ". = .", but
to fix cases where an otherwise empty section has padding added by an
alignment expression that changes with relaxation or .eh_frame
editing. Such a section might have zero size before relaxation and so
be stripped incorrectly.
ld/
* ld.texinfo (Output Section Discarding): Mention assigning to dot
as a way of keeping otherwise empty sections.
* ldexp.c (is_dot, is_value, is_sym_value, is_dot_ne_0,
is_dot_plus_0, is_align_conditional): New predicates.
(exp_fold_tree_1): Set SEC_KEEP when assigning to dot inside an
output section, except for some special cases.
* scripttempl/elfmicroblaze.sc: Use canonical form to align at
end of .heap and .stack.
ld/testsuite/
* ld-shared/elf-offset.ld: Align end of .bss with canonical form
of ALIGN that allows an empty .bss to be removed.
* ld-arm/arm-dyn.ld: Likewise.
* ld-arm/arm-lib.ld: Likewise.
* ld-elfvsb/elf-offset.ld: Likewise.
* ld-mips-elf/mips-dyn.ld: Likewise.
* ld-mips-elf/mips-lib.ld: Likewise.
* ld-arm/arm-no-rel-plt.ld: Remove duplicate ALIGN.
* ld-powerpc/vle-multiseg-1.ld: Remove ALIGN at start of section.
ALIGN address of section instead.
* ld-powerpc/vle-multiseg-2.ld: Likewise.
* ld-powerpc/vle-multiseg-3.ld: Likewise.
* ld-powerpc/vle-multiseg-4.ld: Likewise.
* ld-powerpc/vle-multiseg-6.ld: Likewise.
* ld-scripts/empty-aligned.d: Check section headers not program
headers. Remove xfail and notarget.
* ld-scripts/empty-aligned.t: Use canonical ALIGN for end of .text2.
Hans-Peter Nilsson
Alan Modra
John Marino
Chung-Lin Tang
Christian Svensson
Richard Henderson
Steve Ellcey
Nick Clifton
Jon TURNEY
Cary Coutant
Chris Faylor
H.J. Lu
Yuri Gribov
Dan Mick
Andrew Pinski
Sebastian Huber
Sandra Loosemore
Marcus Shawcroft