Some linker code editing needs to change multiple insns. In some
cases multiple relocations are involved and it is not sufficient to
make the changes independently as relocations are processed, because
doing so might lead to a partial edit. So in order to safely edit we
need all the relocations available in relocate(). Also, to emit
edited relocs corresponding to the edited code sequence we need some
way to pass information from relocate() to relocate_relocs(),
particularly if the edit depends on insns. We can't modify input
relocs in relocate() as they are mmapped PROT_READ, nor it is
particularly clean to write relocs to the output at that stage. So
add a Relocatable_relocs* field to relinfo to mark edited relocs.
Given that relocate is passed the raw reloc pointer, it makes sense to
remove the rel/rela parameter and r_type too. However, that means the
mips relocate() needs to know whether SHT_REL or SHT_RELA relocs are
being processed. So add a rel_type for mips, which also has the
benefit of removing relocate() overloading there.
This patch adds the infrastructure without making use of it.
Note that relinfo->rr will be NULL if not outputting relocations.
* object.h (struct Relocate_info): Add "rr".
* reloc.h (Relocatable_relocs::set_strategy): New accessor.
* reloc.cc (Sized_relobj_file::do_relocate_sections): Init
relinfo.rr for relocate_section and relocate_relocs.
* powerpc.cc (relocate): Add rel_type and preloc parameters.
Delete rela and r_type params, instead recalculate these from
preloc.
(relocate_relocs): Delete Relocatable_relocs* param, instead
use relinfo->rr.
* aarch64.cc: Likewise.
* arm.cc: Likewise.
* i386.cc: Likewise.
* mips.cc: Likewise.
* s390.cc: Likewise.
* sparc.cc: Likewise.
* target.h: Likewise.
* tilegx.cc: Likewise.
* x86_64.cc: Likewise.
* testsuite/testfile.cc: Likewise.
* target-reloc.h (relocate_section): Adjust to suit.
(apply_relocation, relocate_relocs): Likewise.
The GOT entry size is target-dependent. This patch adds a got_entry_size
function to Sized_target class so that a target can provide a value
different from default.
PR gold/19184
* incremental.cc (Got_plt_view_info): Add got_entry_size.
(Local_got_offset_visitor::visit): Replace got_entry_size_
with info_.got_entry_size.
(Local_got_offset_visitor::got_entry_size_): Removed.
(Global_got_offset_visitor::visit): Replace got_entry_size_
with info_.got_entry_size.
(Global_got_offset_visitor::got_entry_size_): Removed.
(Output_section_incremental_inputs::write_got_plt): Initialize
view_info.got_entry_size.
* target.h (Sized_target::got_entry_size): New virtual function.
* x86_64.cc (Target_x86_64::got_entry_size): New function.
This patch updates gold to treat the R_X86_64_GOTPCRELX and
R_X86_64_REX_GOTPCRELX relocations proposed in
https://groups.google.com/forum/#!topic/x86-64-abi/n9AWHogmVY0
the same as R_X86_64_GOTPCREL. FIXME: Gold should perform the
transformations as suggested.
elfcpp/
* x86_64.h (R_X86_64_GOTPCRELX): New.
(R_X86_64_REX_GOTPCRELX): Likewise.
gold/
* x86_64.cc (Target_x86_64<size>::Scan::get_reference_flags):
Treat R_X86_64_GOTPCRELX and R_X86_64_REX_GOTPCRELX the same
as R_X86_64_GOTPCREL.
(Target_x86_64<size>::Scan::local): Likewise.
(Target_x86_64<size>::Scan::possible_function_pointer_reloc):
Likewise.
(Target_x86_64<size>::Scan::global): Likewise.
(Target_x86_64<size>::Relocate::relocate): Likewise.
(Target_x86_64<size>::Relocatable_size_for_reloc::get_size_for_reloc):
Likewise.
We need to check that the output is executable before assuming that we
can replace the reference with zero.
2015-02-02 Cary Coutant <ccoutant@google.com>
gold/
* x86_64.cc (Target_x86_64::Relocate::relocate_tls): Check for
executable output file.
When --warn-unresolved-symbols is used, gold tries to create a dynamic relocation
for it, and gives an internal error if the TLS segment has not already been
created. This patch allows the IE-to-LE optimization for an undefined symbol
when building an executable, which suppresses the dynamic relocation, and
relaxes the requirement to have a TLS segment when applying a relocation for
an undefined symbol.
2015-01-28 Cary Coutant <ccoutant@google.com>
gold/
* x86_64.cc (Target_x86_64::Scan::global): Allow IE-to-LE optimization
for undef TLS symbols.
(Target_x86_64::Relocate::relocate_tls): Likewise.
(Target_x86_64::Relocate::tls_ie_to_le): Likewise.
* x86_64.cc (Target_x86_64<size>::Scan::global): Don't make PLT
entry for R_X86_64_GOTPLT64.
(Target_x86_64<size>::Relocate::relocate): Update comments for
R_X86_64_GOTPLT64.
This patch fixes 2 issues:
1. Since the GOT offset is always negative, we need to use signed int
to support 64-bit GOT relocations.
2. R_X86_64_PLTOFF64 uses the address of GLOBAL_OFFSET_TABLE, which is
the address of the .got.plt section, not the .got section.
to access a global as it expects a GOTPCREL relocation. This is really not
necessary as the linker could use a copy relocation to get around it. This
patch enables copy relocations with pie.
Context:
This is useful because currently the GCC compiler with option -fpie makes
every extern global access go through the GOT. That is because the compiler
cannot tell if a global will end up being defined in the executable or not
and is conservative. This ends up hurting performance when the binary is linked
as mostly static where most of the globals do end up being defined in the
executable. By allowing copy relocs with fPIE, the compiler need not generate
a GOTPCREL(GOT access) for any global access. It can safely assume that all
globals will be defined in the executable and generate a PC-relative access
instead. Gold can then create a copy reloc for only the undefined globals.
gold/
* symtab.h (may_need_copy_reloc): Remove check for position independent
code.
* x86_64.cc (Target_x86_64<size>::Scan::global): Add check for no
position independence before pc absolute may_need_copy_reloc call.
Add check for executable output befor pc relative may_need_copy_reloc
call.
* i386.cc: Ditto.
* arm.cc: Ditto.
* sparc.cc: Ditto.
* tilegx.cc: Ditto.
* powerpc.cc: Add check for no position independence before
may_need_copy_reloc calls.
* testsuite/pie_copyrelocs_test.cc: New file.
* testsuite/pie_copyrelocs_shared_test.cc: New file.
* Makefile.am (pie_copyrelocs_test): New test.
* Makefile.in: Regenerate.
is no PLT.
gold/
PR gold/16900
* i386.cc (Output_data_got_plt_i386): New class.
(Output_data_plt_i386::Output_data_plt_i386): Change type of got_plt
parameter. Change all callers.
(Output_data_plt_i386::layout_): Remove.
(Output_data_plt_i386::got_plt_): Change type.
(Target_i386::got_plt_): Change type. Change all references.
(Target_i386::got_section): Create instance of new class.
(Output_data_got_plt_i386::do_write): New function.
* x86_64.cc (Output_data_got_plt_x86_64): New class.
(Output_data_plt_x86_64::Output_data_plt_x86_64): Change type of got_plt
parameter. Change all callers.
(Output_data_plt_x86_64::layout_): Remove.
(Output_data_plt_x86_64::got_plt_): Change type.
(Target_x86_64::got_plt_): Change type. Change all references.
(Target_x86_64::got_section): Create instance of new class.
(Output_data_got_plt_x86_64::do_write): New function.
(Output_data_plt_x86_64::do_write): Don't write reserved words in GOT.
(Target_x86_64<size>::init_got_plt_for_update): Create instance of new
class.
2013-09-03 Pavel Chupin <pavel.v.chupin@intel.com>
PR gold/15927
* x86_64.cc (Target_x86_64<size>::Scan::global): Use relative
relocation for R_X86_64_32 on x32.
against symbols in discarded sections. Pass is_discarded
param.
* arm.cc, * i386.cc, * sparc.cc, * x86_64.cc (Target_*::Scan::local):
Add is_discarded param.
* powerpc (Target_powerpc::Scan::local): Likewise. Use
is_discarded to flag opd entry as discarded. Don't emit dyn
relocs on such entries.
(Target_powerpc::Scan::global): Similarly detect and handle
such opd entries.
(Powerpc_relobj): Replace opd_ent_shndx_ and opd_ent_off_ with
opd_ent_. Update all uses.
(Powerpc_relobj::get_opd_discard, set_opd_discard): New functions.
(Target_powerpc::relocate_section): Zero out discarded opd
entry relocs.
elfcpp/
PR gold/14091
* x86_64.h (R_X86_64_RELATIVE64): New.
gold/
PR gold/14091
* x86_64.cc (Target_x86_64::Scan::local): For x32, generate
R_X86_64_RELATIVE64 instead of R_X86_64_RELATIVE in case of
R_X86_64_64.
* configure: Regenerate.
gold/
* nacl.cc: New file.
* nacl.h: New file.
* Makefile.am (CCFILES, HFILES): Add them.
* Makefile.in: Regenerate.
* i386.cc (Output_data_plt_i386_nacl): New class.
(Output_data_plt_i386_nacl_exec): New class.
(Output_data_plt_i386_nacl_dyn): New class.
(Target_i386_nacl): New class.
(Target_selector_i386_nacl): New class.
(target_selector_i386): Use it instead of Target_selector_i386.
* x86_64.cc (Output_data_plt_x86_64_nacl): New class.
(Target_x86_64_nacl): New class.
(Target_selector_x86_64_nacl): New class.
(target_selector_x86_64, target_selector_x32): Use it instead of
Target_selector_x86_64.
* arm.cc (Output_data_plt_arm_nacl): New class.
(Target_arm_nacl): New class.
(Target_selector_arm_nacl): New class.
(target_selector_arm, target_selector_armbe): Use it instead of
Target_selector_arm.
* target-select.cc (select_target): Take new Input_file* and off_t
arguments, pass them on to recognize method of selector.
* object.cc (make_elf_sized_object): Update caller.
* parameters.cc (parameters_force_valid_target): Likewise.
* incremental.cc (make_sized_incremental_binary): Likewise.
* target-select.h: Update decl.
(Target_selector::recognize): Take new Input_file* argument,
pass it on to do_recognize.
(Target_selector::do_recognize): Take new Input_file* argument.
* freebsd.h (Target_selector_freebsd::do_recognize): Likewise.
* powerpc.cc (Target_selector_powerpc::do_recognize): Likewise.
* sparc.cc (Target_selector_sparc::do_recognize): Likewise.
* testsuite/testfile.cc (Target_selector::do_recognize): Likewise.
* target.h (Target::Target_info): New members isolate_execinstr
and rosegment_gap.
(Target::isolate_execinstr, Target::rosegment_gap): New methods.
* arm.cc (Target_arm::arm_info): Update initializer.
* i386.cc (Target_i386::i386_info): Likewise.
* powerpc.cc (Target_powerpc::powerpc_info): Likewise.
* sparc.cc (Target_sparc::sparc_info): Likewise.
* x86_64.cc (Target_x86_64::x86_64_info): Likewise.
* testsuite/testfile.cc (Target_test::test_target_info): Likewise.
* layout.cc (Layout::attach_allocated_section_to_segment):
Take new const Target* argument. If target->isolate_execinstr(), act
like --rosegment.
(Layout::find_first_load_seg): Take new const Target* argument;
if target->isolate_execinstr(), reject PF_X segments.
(Layout::relaxation_loop_body): Update caller.
(Layout::set_segment_offsets): If target->isolate_execinstr(),
reset file offset to zero when we hit LOAD_SEG, and then do a second
loop over the segments before LOAD_SEG to reassign offsets after
addresses have been determined. Handle target->rosegment_gap().
(Layout::attach_section_to_segment): Take new const Target* argument;
pass it to attach_allocated_section_to_segment.
(Layout::make_output_section): Update caller.
(Layout::attach_sections_to_segments): Take new const Target* argument;
pass it to attach_section_to_segment.
* gold.cc (queue_middle_tasks): Update caller.
* layout.h (Layout): Update method decls with new arguments.
* arm.cc (Target_arm::Target_arm): Take optional argument for the
Target_info pointer to use.
(Target_arm::do_make_data_plt): New virtual method.
(Target_arm::make_data_plt): New method that calls it.
(Target_arm::make_plt_entry): Use it.
(Output_data_plt_arm::Output_data_plt_arm): Take additional argument
for the section alignment.
(Output_data_plt_arm::do_first_plt_entry_offset): New abstract virtual
method.
(Output_data_plt_arm::first_plt_entry_offset): Call it.
(Output_data_plt_arm::do_get_plt_entry_size): New abstract virtual
method.
(Output_data_plt_arm::get_plt_entry_size): Call it.
(Output_data_plt_arm::do_fill_plt_entry): New abstract virtual method.
(Output_data_plt_arm::fill_plt_entry): New method that calls it.
(Output_data_plt_arm::do_fill_first_plt_entry): New abstract virtual
method.
(Output_data_plt_arm::fill_first_plt_entry): New method that calls it.
(Output_data_plt_arm::set_final_data_size): Use get_plt_entry_size
method instead of sizeof(plt_entry).
(Output_data_plt_arm::add_entry): Likewise.
Use first_plt_entry_offset method instead of sizeof(first_plt_entry).
(Target_arm::first_plt_entry_offset): Call method on this->plt_ rather
than static method.
(Target_arm::plt_entry_size): Likewise.
(Output_data_plt_arm::first_plt_entry, Output_data_plt_arm::plt_entry):
Move to ...
(Output_data_plt_arm_standard): ... here, new class.
(Output_data_plt_arm::do_write): Move guts of PLT filling to...
(Output_data_plt_arm_standard::do_fill_first_plt_entry): ... here ...
(Output_data_plt_arm_standard::do_fill_plt_entry): ... and here.
* x86_64.cc (Output_data_plt_x86_64::Output_data_plt_x86_64):
Take additional argument for the PLT entry size.
(Output_data_plt_x86_64::get_tlsdesc_plt_offset):
Use get_plt_entry_size method rather than plt_entry_size variable.
(Output_data_plt_x86_64::reserve_slot): Likewise.
(Output_data_plt_x86_64::do_adjust_output_section): Likewise.
(Output_data_plt_x86_64::add_entry): Likewise.
(Output_data_plt_x86_64::add_local_ifunc_entry): Likewise.
(Output_data_plt_x86_64::address_for_global): Likewise.
(Output_data_plt_x86_64::address_for_local): Likewise.
(Output_data_plt_x86_64::set_final_data_size): Likewise.
(Output_data_plt_x86_64::first_plt_entry_offset): Likewise.
Make method non-static.
(Output_data_plt_x86_64::do_get_plt_entry_size): New abstract virtual
method.
(Output_data_plt_x86_64::get_plt_entry_size): Just call that.
(Output_data_plt_x86_64::do_add_eh_frame): New abstract virtual method.
(Output_data_plt_x86_64::add_eh_frame): New method to call it.
(Output_data_plt_x86_64::do_fill_first_plt_entry): New abstract
virtual method.
(Output_data_plt_x86_64::fill_first_plt_entry): New method to call it.
(Output_data_plt_x86_64::do_fill_plt_entry): New abstract
virtual method.
(Output_data_plt_x86_64::fill_plt_entry): New method to call it.
(Output_data_plt_x86_64::do_fill_tlsdesc_entry): New abstract
virtual method.
(Output_data_plt_x86_64::fill_tlsdesc_entry): New method to call it.
(Output_data_plt_x86_64::plt_entry_size)
(Output_data_plt_x86_64::first_plt_entry)
(Output_data_plt_x86_64::plt_entry)
(Output_data_plt_x86_64::tlsdesc_plt_entry)
(Output_data_plt_x86_64::plt_eh_frame_fde_size)
(Output_data_plt_x86_64::plt_eh_frame_fde): Move to ...
(Output_data_plt_x86_64_standard): ... here, new class.
(Target_x86_64::Target_x86_64): Take optional argument for the
Target_info pointer to use.
(Target_x86_64::do_make_data_plt): New virtual method.
(Target_x86_64::make_data_plt): New method to call it.
(Target_x86_64::init_got_plt_for_update): Use that.
Call this->plt_->add_eh_frame method here.
(Output_data_plt_x86_64::init): Don't do add_eh_frame_for_plt here.
(Target_x86_64::first_plt_entry_offset): Call method on this->plt_
rather than static method.
(Target_x86_64::plt_entry_size): Likewise.
(Output_data_plt_x86_64::do_write): Use get_plt_entry_size method
rather than plt_entry_size variable. Move guts of PLT filling to...
(Output_data_plt_x86_64_standard::do_fill_first_plt_entry): ... here ...
(Output_data_plt_x86_64_standard::do_fill_plt_entry): ... and here ...
(Output_data_plt_x86_64_standard::do_fill_tlsdesc_entry): ... and here.
* i386.cc (Output_data_plt_i386::Output_data_plt_i386): Take
additional argument for the section alignment.
Don't do add_eh_frame_for_plt here.
(Output_data_plt_i386::first_plt_entry_offset): Make the method
non-static. Use get_plt_entry_size method rather than plt_entry_size
variable.
(Output_data_plt_i386::do_get_plt_entry_size): New abstract virtual
method.
(Output_data_plt_i386::get_plt_entry_size): Call it.
(Output_data_plt_i386::do_add_eh_frame): New abstract virtual method.
(Output_data_plt_i386::add_eh_frame): New method to call it.
(Output_data_plt_i386::do_fill_first_plt_entry): New abstract virtual
method.
(Output_data_plt_i386::fill_first_plt_entry): New method to call it.
(Output_data_plt_i386::do_fill_plt_entry): New abstract virtual
method.
(Output_data_plt_i386::fill_plt_entry): New method to call it.
(Output_data_plt_i386::set_final_data_size): Use get_plt_entry_size
method instead of plt_entry_size.
(Output_data_plt_i386::plt_entry_size)
(Output_data_plt_i386::plt_eh_frame_fde_size)
(Output_data_plt_i386::plt_eh_frame_fde): Move to ...
(Output_data_plt_i386_standard): ... here, new class.
(Output_data_plt_i386_exec): New class.
(Output_data_plt_i386::exec_first_plt_entry): Move to ...
(Output_data_plt_i386_exec::first_plt_entry): ... here.
(Output_data_plt_i386::exec_plt_entry): Move to ...
(Output_data_plt_i386_exec::plt_entry): ... here.
(Output_data_plt_i386_dyn): New class.
(Output_data_plt_i386::first_plt_entry): Move to ...
(Output_data_plt_i386_dyn::first_plt_entry): ... here.
(Output_data_plt_i386::dyn_plt_entry): Move to ...
(Output_data_plt_i386_dyn::plt_entry): ... here.
(Target_i386::Target_i386): Take optional argument for the Target_info
pointer to use.
(Target_i386::do_make_data_plt): New virtual method.
(Target_i386::make_data_plt): New method to call it.
(Target_i386::make_plt_section): Use that.
Call this->plt_->add_eh_frame method here.
(Output_data_plt_i386::add_entry): Use get_plt_entry_size method
rather than plt_entry_size variable.
(Output_data_plt_i386::add_local_ifunc_entry): Likewise.
(Output_data_plt_i386::address_for_local): Likewise.
(Output_data_plt_i386::do_write): Likewise.
Move guts of PLT filling to...
(Output_data_plt_i386_exec::do_fill_first_plt_entry): ... here ...
(Output_data_plt_i386_exec::do_fill_plt_entry): ... and here ...
(Output_data_plt_i386_dyn::do_fill_first_plt_entry): ... and here ...
(Output_data_plt_i386_dyn::do_fill_plt_entry): ... and here.
Change-Id: Id24b95600489835ff5e860a39c147203d4380c2b
2012-01-22 H.J. Lu <hongjiu.lu@intel.com>
* x86_64.cc (gc_process_relocs): Add typename on types used in
template.
(scan_relocs): Likewise.
(relocate_section): Likewise.
(apply_relocation): Likewise.
2012-01-10 H.J. Lu <hongjiu.lu@intel.com>
* x86_64.cc (Scan::check_non_pic): Allow R_X86_64_32 for x32.
(Scan::local): Use R_X86_64_RELATIVE relocation for R_X86_64_32
under x32.
Use abstract base class for GOT.
* gold/output.h (class Output_data_got_base): New abstract base class.
(class Output_data_got): Derive from new base class, adjust ctors.
(Output_data_got::reserve_slot): Make virtual; rename to
do_reserve_slot; Adjust callers.
* gold/target.h (Sized_target::init_got_plt_for_update): Return
pointer to abstract base class.
* gold/x86_64.cc (Target_x86_64::init_got_plt_for_update): Likewise.
(Relobj::local_plt_offset): New function.
(Relobj::local_has_got_offset): New function.
(Relobj::local_got_offset): New function.
(Relobj::set_local_got_offset): New function.
(Relobj::do_local_symbol_value): New pure virtual function.
(Relobj::do_local_plt_offset): Likewise.
(Relobj::do_local_has_got_offset): Likewise.
(Relobj::do_local_got_offset): Likewise.
(Relobj::do_set_local_got_offset): Likewise.
(Sized_relobj::do_local_has_got_offset): Rename from
local_has_got_offset.
(Sized_relobj::do_local_got_offset): Rename from local_got_offset.
(Sized_relobj::do_set_local_got_offset): Rename from
set_local_got_offset.
(Sized_relobj_file::do_local_plt_offset): Rename from
local_plt_offset.
(Sized_relobj_file::do_local_symbol_value): New function.
* object.cc (Sized_relobj_file::do_local_plt_offset): Rename from
local_plt_offset.
* output.cc (Output_data_got::Got_entry::write): Change object to
Relobj. Use local_symbol_value.
(Output_data_got::add_global_with_rel): Change rel_dyn to
Output_data_reloc_generic*. Use add_global_generic.
(Output_data_got::add_global_with_rela): Remove. Change all
callers to use add_global_with_rel.
(Output_data_got::add_global_pair_with_rel): Change rel_dyn to
Output_data_reloc_generic*. Use add_global_generic.
(Output_data_got::add_global_pair_with_rela): Remove. Change all
callers to use add_global_pair_with_rel.
(Output_data_got::add_local): Change object to Relobj*.
(Output_data_got::add_local_plt): Likewise.
(Output_data_got::add_local_with_rel): Change object to Relobj*,
change rel_dyn to Output_data_reloc_generic*. Use
add_local_generic.
(Output_data_got::add_local_with_rela): Remove. Change all
callers to use all_local_with_rel.
(Output_data_got::add_local_pair_with_rel): Change object to
Relobj*, change rel_dyn to Output_data_reloc_generic*. Use
add_output_section_generic.
(Output_data_got::add_local_pair_with_rela): Remove. Change all
callers to use add_local_pair_with_rel.
(Output_data_got::reserve_local): Change object to Relobj*.
* output.h: (class Output_data_reloc_generic): Add pure virtual
declarations for add_global_generic, add_local_generic,
add_output_section_generic.
(class Output_data_reloc) [SHT_REL, SHT_RELA]: Implement new
functions for Output_data_reloc_generic. Update declarations for
changes listed in output.cc.
(class Output_data_got): Change template parameter to got_size.
Don't define Rel_dyn or Rela_dyn. Update declarations per above.
* incremental.h (Sized_relobj_incr::do_local_symbol_value): New
function.
(Sized_relobj_incr::do_local_plt_offset): New function.
* copy-relocs.cc (Copy_relocs::Copy_reloc_entry::emit): Call
add_global_generic.
* gold/output.cc (Output_reloc::Output_reloc): Add use_plt_offset flag.
(Output_reloc::symbol_value): Return PLT offset if flag is set.
* gold/output.h (class Output_reloc): Add use_plt_offset flag.
(Output_reloc::type_): Adjust size of bit field.
(Output_reloc::use_plt_offset_): New bit field.
(class Output_data_reloc): Adjust all calls to Output_reloc_type.
(Output_data_reloc::add_local_relative): (RELA only) Add use_plt_offset
flag. Adjust all callers.
* gold/x86_64.cc (Target_x86_64::Scan::local): Check for IFUNC when
creating RELATIVE relocations.
(Output_data_plt_i386::Output_data_plt_i386): Initialize layout_.
(Output_data_plt_i386::do_write): Write address of .dynamic
section to first entry in .got.plt section.
* x86_64.cc (class Output_data_plt_x86_64): Add layout_ field.
(Output_data_plt_x86_64::Output_data_plt_x86_64) [both versions]:
Initialize layout_.
(Output_data_plt_x86_64::do_write): Write address of .dynamic
section to first entry in .got.plt section.
* layout.h (Layout::dynamic_section): New function.
