* arm.cc (Target_arm::do_finalize_sections): Skip processor specific
flags and attributes merging if an input file is a binary file.
* fileread.cc (Input_file::open): Record format of original file.
* fileread.h (Input_file::Format): New enum type.
(Input_file::Input_file): Initialize data member format_.
(Input_file::format): New method definition.
(Input_file::format_):: New data member.
* arm.cc (Arm_output_data_got): New class.
(ARM_TCB_SIZE): New constant
(Target_arm): Use Arm_output_data_got instead of Output_data_got.
(Arm_output_section::fix_exidx_coverage): Add a parameter for layout.
If user uses a script with a SECTIONS clause, issue only a warning
for a misplaced EXIDX input section. Otherwise, issue an error.
(Arm_relobj::do_gc_process_relocs): Exit early if we are not doing
garbage collection.
(Target_arm::got_mode_index_entry): Handle static linking.
(Target_arm::Scan::local): Ditto.
(Target_arm::Scan::global): Ditto.
(Target_arm::Relocate::relocate_tls): Handle static linking. Fix
all incorrectly implemented relocations.
(Target_arm::fix_exidx_coverage): Pass layout to
Arm_output_section::fix_exidx_coverage.
* layout.cc (Layout::section_name_mapping): Remove trailing dots
from ".ARM.exidx." and ".ARM.extab.".
* gold-threads.h (Once::~Once): Explicitly define virtual destructor.
* icf.cc (get_section_contents): Cast snprintf arguments to long long
types to avoid warnings due to different uint64_t implementations
on different hosts.
* gc.h (gc_process_relocs): Change vectors to point to the new list.
Add reloc offset information.
* icf.cc (get_section_contents): Change iterators to point to the new
vectors. Add reloc offset information to the contents.
* icf.h (Icf::Sections_reachable_info): New typedef.
(Icf::Sections_reachable_list): New typedef.
(Icf::Offset_info): New typedef.
(Icf::Reloc_info): New struct typedef.
(Icf::Reloc_info_list): New typedef.
(Icf::symbol_reloc_list): Delete method.
(Icf::addend_reloc_list): Delete method.
(Icf::section_reloc_list): Delete method.
(Icf::reloc_info_list): New method.
(Icf::reloc_info_list_): New member.
* arm-reloc.def: Mark R_ARM_TLS_GD32, R_ARM_TLS_LDM32,
R_ARM_TLS_LDO32, R_ARM_TLS_IE32 and R_ARM_TLS_LE32 are implemented.
* arm.cc (Arm_relocation_functions): New forward declaration.
(Target_arm::Target_arm): Initialize new data members
got_mod_index_offset_ and tls_base_symbol_defined_.
(Target_arm::Relocate::relocate_tls): New method.
(Target_arm::optimize_tls_reloc, Target_arm::define_tls_base_symbol,
Target_arm::got_mod_index_entry, Target_arm::rel_tls_desc_section):
New methods.
(Target_arm::Got_type): Add GOT_TYPE_TLS_NOFFSET, GOT_TYPE_OFFSET,
GOT_TYPE_TLS_PAIR and GOT_TYPE_TLS_DESC.
(Target_arm::got_mod_index_offset_,
Target_arm::tls_base_symbol_defined_): New data members.
(Target_arm::Scan::local, Target::Scan::global,
Target_arm::Relocate::relocate): Handle 32-bit initial TLS
relocations.
* arm.cc (Arm_relobj::find_linked_text_section): New method.
(Arm_relobj::make_exidx_input_section): Pass section index of linked
text section as a parameter becuase some broken tools may not set
the link in section header.
(Target_arm::has_got_section): New method.
(Target_arm::scan_section_for_cortex_a8_stubs): Treat an input section
without any mapping symbol as data only. Remove warning.
(Arm_relobj::do_read_synbols): If an EXIDX input section has no
link in its section header, try to discover the link by inspecting the
REL31 relocation at the beginning of the section.
(Target_arm::Scan::check_non_pic): Report name of offending relocation
in error message.
(Target_arm::Scan::global): Treat any reference to the symbol
_GLOBAL_OFFSET_TABLE_ as a GOT access.
* arm.cc (Scan::local_reloc_may_be_function_pointer): New function.
(Scan::global_reloc_may_be_function_pointer): New function.
* sparc.cc (Scan::local_reloc_may_be_function_pointer): New function.
(Scan::global_reloc_may_be_function_pointer): New function.
* powerpc.cc (Scan::local_reloc_may_be_function_pointer): New function.
(Scan::global_reloc_may_be_function_pointer): New function.
* i386.cc (Scan::local_reloc_may_be_function_pointer): New function.
(Scan::global_reloc_may_be_function_pointer): New function.
* x86_64.cc (Scan::local_reloc_may_be_function_pointer): New function.
(Scan::global_reloc_may_be_function_pointer): New function.
(Scan::possible_function_pointer_reloc): New function.
(Target_x86_64::can_check_for_function_pointers): New function.
* gc.h (gc_process_relocs): Scan relocation types to determine if
function pointers were taken for targets that support it.
* icf.cc (Icf::find_identical_sections): Include functions for
folding in safe ICF whose pointer is not taken.
* icf.h (Secn_fptr_taken_set): New typedef.
(fptr_section_id_): New member.
(section_has_function_pointers): New function.
(set_section_has_function_pointers): New function.
(check_section_for_function_pointers): New function.
* options.h: Fix comment for safe ICF option.
* target.h (can_check_for_function_pointers): New function.
* testsuite/Makefile.am: Add icf_safe_so_test test case.
Modify icf_safe_test for X86-64.
* testsuite/Makefile.in: Regenerate.
* testsuite/icf_safe_so_test.cc: New file.
* testsuite/icf_safe_so_test.sh: New file.
* testsuite/icf_safe_test.cc (kept_func_3): New function.
(main): Change to take pointer to function kept_func_3.
* testsuite/icf_safe_test.sh (arch_specific_safe_fold): Check if safe
folding is done correctly for X86-64.
* arm.cc (Target_arm::Scan::local): Fix bugs in relocation handling.
(Target_arm::Scan::global): Ditto. Also remove a comment before the
beginning of function.
(Target_arm::Relocate::relocate): Remove error messages for MOVW_ABS
and MOVT_ABS relocations. Those are non issued in scanning. Fix
parameter is_32bit in calls to should_apply_static_reloc.
* testsuite/Makefile.am (check_SCRIPTS): Add arm_abs_global.sh.
(check_DATA): Add arm_abs_global.stdout.
(arm_abs_lib.o, libarm_abs.so, arm_abs_global.o, arm_abs_global,
arm_abs_global.stdout): New rules.
(MOSTLLYCLEANFILES): Add arm_abs_global
* Makefile.in: Regenerate.
* testsuite/arm_abs_global.s: New file.
* testsuite/arm_abs_global.sh: Ditto.
* testsuite/arm_abs_lib.s: Ditto.
Read_relocs task.
(queue_middle_tasks): Likewise, and also for Scan_relocs. Run
Allocate_commons_task first.
* reloc.cc (Read_relocs::run): Pass next_blocker_ down to next
task, rather than symtab_lock_.
(Gc_process_relocs::~Gc_process_relocs): New function.
(Gc_process_relocs::is_runnable): Check this_blocker_.
(Gc_process_relocs::locks): Use next_blocker_ rather than
blocker_.
(Scan_relocs::~Scan_relocs): New function.
(Scan_relocs::is_runnable): Check this_blocker_ rather than
symtab_lock_.
(Scan_relocs::locks): Drop symtab_lock_ and blocker_. Add
next_blocker_.
* reloc.h (class Read_relocs): Drop symtab_lock_ and blocker_
fields. Add this_blocker_ and next_blocker_ fields. Adjust
constructor accordingly.
(class Gc_process_relocs): Likewise.
(class Scan_relocs): Likewise.
* common.h (class Allocate_commons_task): Remove symtab_lock_
field, and corresponding constructor parameter.
* common.cc (Allocate_commons_tasK::is_runnable): Remove use of
symtab_lock_.
(Allocate_commons_task::locks): Likewise.
(class Initialize_lock): Rewrite as child of Once.
* gold-threads.cc (class Once_initialize): Define.
(once_pointer_control): New static variable.
(once_pointer, once_arg): New static variables.
(c_run_once): New static function.
(Once::Once, Once::run_once, Once::internal_run): New functions.
(class Initialize_lock_once): Remove.
(initialize_lock_control): Remove.
(initialize_lock_pointer): Remove.
(initialize_lock_once): Remove.
(Initialize_lock::Initialize_lock): Move to gold-threads.h.
(Initialize_lock::initialize): Rewrite.
(Initialize_lock::do_run_once): New function.
* archive.cc (Archive::interpret_header): Only clear name if it is
not already empty.
* fileread.cc: Include "gold-threads.h"
(file_counts_lock): New static variable.
(file_counts_initialize_lock): Likewise.
(File_read::release): Only increment counts when using --stats.
Use a lock around the increment.
* parameters.cc (class Set_parameters_target_once): Define.
(set_parameters_target_once): New static variable.
(Parameters::Parameters): Move here from parameters.h.
(Parameters::set_target): Rewrite.
(Parameters::set_target_once): New function.
(Parameters::clear_target): Move here and rewrite.
* parameters.h (class Parameters): Update declarations. Add
set_parameters_target_once_ field.
(Parameters::Parameters): Move to parameters.cc.
(Parameters::clear_target): Likewise.
* readsyms.cc (Read_symbols::do_group): Create a Start_group
task.
(Start_group::~Start_group): New function.
(Start_group::is_runnable): New function.
(Start_group::locks, Start_group::run): New functions.
(Finish_group::run): Change saw_undefined to size_t.
* readsyms.h (class Start_group): Define.
(class Finish_group): Change saw_undefined_ field to size_t.
(Finish_group::Finish_group): Remove saw_undefined and
this_blocker parameters. Change all callers.
(Finish_group::set_saw_undefined): New function.
(Finish_group::set_blocker): New function.
* symtab.h (class Symbol_table): Change saw_undefined to return
size_t. Change saw_undefined_ field to size_t.
* target-select.cc (Set_target_once::do_run_once): New function.
(Target_selector::Target_selector): Initialize set_target_once_
field. Don't initialize lock_ and initialize_lock_ fields.
(Target_selector::instantiate_target): Rewrite.
(Target_selector::set_target): New function.
* target-select.h (class Set_target_once): Define.
(class Target_selector): Update declarations. Make
Set_target_once a friend. Remove lock_ and initialize_lock_
fields. Add set_target_once_ field.
queueing any tasks.
* gold.cc (queue_middle_gc_tasks): Likewise. Fix final blocker.
(queue_middle_tasks): Add all blockers before queueing any tasks.
(queue_final_tasks): Likewise.
* token.h (Task_token::add_blockers): New function.
* object.h (Input_objects::number_of_relobjs): New function.
that takes two Output_data objects.
(Output_data_dynamic::Dynamic_entry): Create storage for secondary
entry param. Handle it in initializers.
* output.cc (Output_data_dynamic::Dynamic_entry::write): For
DYNAMIC_SECTION_SIZE, add in second object size if non-NULL.
* layout.h (Layout::add_target_dynamic_tags): Add dynrel_includes_plt
arg.
* layout.cc (Layout::add_target_dynamic_tags): If dynrel_includes_plt,
and .rela.plt exists, set DT_REL{,A}SZ to sum of .rela.dyn and .rela.plt
* arm.cc (Target_arm::do_finalize_sections): Update to pass false
for dynrel_includes_plt.
* i386.cc (Target_i386::do_finalize_sections): Likewise.
* x86_64.cc (Target_x86_64::do_finalize_sections): Likewise.
* sparc.cc (Target_sparc::make_plt_entry): Force .rela.dyn to be output
before .rela.plt
(Target_sparc::do_finalize_sections): Update to pass true for
dynrel_includes_plt.
* powerpc.cc (Target_powerpc::make_plt_entry): Force .rela.dyn to be
output before .rela.plt
(Target_powerpc::do_finalize_sections): Update to pass true for
dynrel_includes_plt when 32-bit.
* arm.cc (Arm_relobj::simple_input_section_output_address): New
method.
(Arm_relobj::section_needs_cortex_a8_stub_scanning,
Arm_relobj::scan_section_for_cortex_a8_stubs,
Arm_relobj::do_relocation_section): Instead of calling
Output_section::output_address, use faster
Arm_relobj::simple_input_section_output_address.
2010-02-08 David S. Miller <davem@davemloft.net>
* sparc.cc (Target_sparc::Relocate::relocate): If relocation offset is
unaligned for R_SPARC_16, R_SPARC_32, or R_SPARC_64, use the unaligned
relocation helper function.
PR 11247
* arm.cc (Arm_relobj::section_is_scannable): New method.
(Arm_relobj::section_needs_reloc_stub_scanning): Use it.
(Arm_relobj::section_needs_cortex_a8_stub_scanning): Same.
PR 11247
* arm-reloc-property.cc (cstdio): Include.
* configure.ac (targetobjs): Remove duplicates.
* configure: Regenerate.
* resolve.cc (Symbol_table::resolve): Explicit instantiate both
big and little endian version for a given address size.
* arm-reloc-property.cc
(Arm_reloc_property_table::reloc_name_in_error_message): New method
definition.
* arm-reloc-property.h
(Arm_reloc_property_table::get_implemented_static_reloc_property):
New method definition.
(Arm_reloc_property_table::reloc_name_in_error_message): New method
declaration.
* arm-reloc.def (THM_MOVT_ABS, THM_MOVT_PREL, THM_MOVT_BREL): Change
overflow to N.
(GOT_PREL): Change implemented to Y.
* arm.cc (Target_arm::reloc_uses_thumb_bit): Remove method.
(Target_arm::Relocate::reloc_needs_sym_origin): Remove method.
(Arm_relocate_functions::movw_abs_nc): Remove method.
(Arm_relocate_functions::movt_abs): Ditto.
(Arm_relocate_functions::thm_movw_abs_nc): Ditto.
(Arm_relocate_functions::thm_movt_abs): Ditto.
(Arm_relocate_functions::movw_rel_nc): Ditto.
(Arm_relocate_functions::movw_rel): Ditto.
(Arm_relocate_functions::movt_rel): Ditto.
(Arm_relocate_functions:thm_movw_rel_nc): Ditto.
(Arm_relocate_functions:thm_movw_rel): Ditto.
(Arm_relocate_functions:thm_movt_rel): Ditto.
(Arm_relocate_functions::movw, Arm_relocate_functions::movt,
(Arm_relocate_functions::thm_movw, Arm_relocate_functions::thm_movt):
New method definitions.
(Arm_relocation_functions::arm_grp_alu): Add assertion for group index.
(Arm_relocation_functions::arm_grp_ldr): Ditto.
(Arm_relocation_functions::arm_grp_ldrs): Ditto.
(Arm_relocation_functions::arm_grp_ldc): Ditto.
(Target_arm::Relocate::relocate): Check for non-static or
unimplemented relocation code and exit early. Change calls to
Target_arm::reloc_uses_thumb_bit and
Target_arm::Reloc::reloc_needs_sym_origin to use relocation property
instead. Refactor code to handle similar relocations to increase
code sharing. Remove check for unsupported relocation code in switch
statement.
(Target_arm::Relocatable_size_for_reloc::get_size_for_reloc): Use
relocation property table to find out size. Change error message to
print out the name of a relocation code instead of the numeric value.
(Target_arm::scan_reloc_for_stub): Use relocation property table
instead of calling Target_arm::reloc_uses_thumb_bit().
* arm.cc (Arm_exidx_fixup::Arm_exidx_fixup): Initialize
first_output_text_section_.
(Arm_exidx_fixup::first_output_text_section): New method definition.
(Arm_exidx_fixup::first_output_text_section_): New data member.
(Arm_exidx_fixup::process_exidx_section): Record the first text
output section seen.
(Arm_output_section::fix_exidx_coverage): Set correct linked section
and entsize in output section header.
* gold/arm.cc: Added support for the ARM relocations: R_ARM_THM_PC8,
R_ARM_THM_PC12, R_ARM_THM_ALU_PREL_11_0.
(Arm_relocate_functions::thm_alu11): New Method.
(Arm_relocate_functions::thm_pc8): New Method.
(Arm_relocate_functions::thm_pc12): New Method.
(Target_arm::Scan::local): Handle the relocations.
(Target_arm::Scan::global): Likewise.
(Target_arm::Relocate::relocate): Likewise.
(Target_arm:Relocatable_size_for_reloc::get_size_for_reloc): Likewise.
* arm.cc (Arm_relobj::Arm_relobj): Initialize new data member
output_local_symbol_count_needs_update_.
(Arm_relobj::output_local_symbol_count_needs_update,
Arm_relobj::set_output_local_symbol_count_needs_update,
Arm_relobj::update_output_local_symbol_count): New methods.
(Arm_relobj::output_local_symbol_count_needs_update_): New data
member.
(Arm_exidx_cantunwind::do_fixed_endian_write): Write address
of pointed function as in a R_ARM_PREL31 relocation.
(Arm_output_section<big_endian>::fix_exidx_coverage): Mark objects
for output local symbol count updating.
(Target_arm::do_relax): Update output local symbol counts in objects
if necessary.
* object.h (Sized_relobj::set_output_local_symbol_count): New method.
(Target_arm::reloc_needs_sym_origin): New method.
(Arm_relocate_functions::calc_grp_kn): New method.
(Arm_relocate_functions::calc_grp_residual): New method.
(Arm_relocate_functions::calc_grp_gn): New method.
(Arm_relocate_functions::arm_grp_alu): New Method.
(Arm_relocate_functions::arm_grp_ldr): New Method.
(Arm_relocate_functions::arm_grp_ldrs): New Method.
(Arm_relocate_functions::arm_grp_ldc): New Method.
(Target_arm::Scan::local): Handle the ARM group relocations.
(Target_arm::Scan::global): Likewise.
(Target_arm::Relocate::relocate): Likewise.
(Target_arm::Relocatable_size_for_reloc::get_size_for_reloc):
Likewise.
* arm.cc (set): Include.
(class Arm_exidx_fixup): Change type of last_input_section_ to const
pointer type.
(Arm_output_section::Text_section_list): New type.
(Arm_output_section::append_text_sections_to_list): New method.
(Arm_output_section::fix_exidx_coverage): Ditto.
(Arm_relobj::Arm_relobj): Initialize exidx_section_map_.
(Arm_relobj::convert_input_section_to_relaxed_section): Use
Relobj::set_section_offset() instead of
Sized_relobj::invalidate_section_offset().
(Arm_relobj::section_needs_reloc_stub_scanning): Add an extra
parameter for section headers. Ignore relocation sections for
unallocated sections and EXIDX sections.
(Target_arm::fix_exidx_coverage): New method.
(Target_arm::output_section_address_less_than): New type.
(Arm_exidx_fixup::add_exidx_cantunwind_as_needed): Use index of the
linked text section instead of the EXIDX section.
(Arm_output_section::create_stub_group): Add an assertion to check
that this is not an EXIDX output section.
(Arm_output_section::append_text_sections_to_list): New method.
(Arm_output_section::fix_exidx_coverage): Ditto.
(Arm_relobj::scan_sections_for_stubs): Adjust call to
Arm_relobj::section_needs_reloc_stub_scanning.
(Target_arm::do_relax): Fix EXIDX output section coverage in the
first pass.
(Target_arm::fix_exidx_coverage): New method.
* object.h (Relobj::set_output_section): New method.
(Sized_relobj::invalidate_section_offset): Remove method.
(Sized_relobj::do_invalidate_section_offset): Remove method.
(Sized_relobj::do_set_section_offset): Handle offset value -1.
* arm.cc (Target_arm::do_relax): Record an output section for section
offset adjustment it contains any stub table that has changed.
* layout.cc (Layout::clean_up_after_relaxation): Adjust section
offsets in an output section if necessary.
* output.cc (Output_section::Output_section): Initialize
section_offsets_need_adjustments_.
(Output_section::add_input_section_for_script): Renamed to
Output_section::add_simple_input_section.
(Output_section::save_states): Add a comment.
(Output_section::discard_states): New method defintion.
(Output_section::adjust_section_offsets): Same.
* output.h (Output_section::add_input_section_for_script): Renamed to
Output_section::add_simple_input_section.
(Output_section::discard_states): New method declaration.
(Output_section::adjust_section_offsets): Same.
(Output_section::section_offsets_need_adjustment,
Output_section::set_section_offsets_need_adjustment): New method
definitions.
(Output_section::section_offsets_need_adjustment_): New data member.
* script-sections.cc
(Output_section_element_input::set_section_address): Adjust code for
renaming of Output_section::add_input_section_for_script.
(Orphan_output_section::set_section_address): Same.
* gold/arm.cc (Target_arm): Updated fix_v4bx method and usage of
Fix_v4bx enum values .
* gold/options.h (General_options): New option definitions.
(General_options::fix_v4bx): New method.
(General_options::Fix_v4bx): New enum.
* gold/options.cc (General_options::parse_fix_v4bx): New method.
(General_options::parse_fix_v4bx_interworking): New method.
* arm.cc (Arm_exidx_input_section): New class.
(Arm_relobj::exidx_input_section_by_link,
Arm_relobj::exidx_input_section_by_shndx,
Arm_relobj::make_exidx_input_section): New methods.
(read_arm_attributes_section): Remove.
(Arm_relobj::do_read_symbols): Look for ARM.exidx sections and record
information about them.
(Arm_dynobj::do_read_symbols): Move code in read_arm_attributes_section
to here.
* arm.cc (Target_arm::Arm_input_section_map): Change key type from
Input_section_specifier to Section_id.
(Target_arm::new_arm_input_section: Adjust code for change of key
type.
(Target_arm::find_arm_input_section): Ditto.
* gc.h (object.h): Include for Section_id nand Section_id_hash.
(Section_id): Remove.
(Garbage_collection::Section_id_hash): Remove.
* icf.h (object.h): Include for Section_id nand Section_id_hash.
(Section_id): Remove.
(Icf::Section_id_hash): Remove.
* object.h (Section_id, Const_section_id, Section_id_hash,
Const_section_id_hash): New type definitions.
* output.cc (Output_section::add_relaxed_input_section): Change to
use Const_section_id instead of Input_section_specifier as key type.
(Output_section::add_merge_input_section): Ditto.
(Output_section::build_relaxation_map): Change to use Section_id
instead of Input_section_specifier as key type.
(Output_section::convert_input_sections_in_list_to_relaxed_sections):
Ditto.
(Output_section::convert_input_sections_to_relaxed_sections): Change
to use Const_section_id instead of Input_section_specifier as key type.
(Output_section::find_merge_section): Ditto.
(Output_section::find_relaxed_input_section): Ditto.
* output.h (Input_section_specifier): Remove class.
(Output_section::Output_section_data_by_input_section_map): Change
key type to Const_section_id.
(Output_section::Output_relaxed_input_section_by_input_section_map):
Ditto.
(Output_section::Relaxation_map): Change key type to Section_id.
* elfcpp.h (PN_XNUM): Define.
gold/:
* output.cc (Output_section_headers::do_sized_write): Write large
segment count to sh_info field.
(Output_file_header::do_sized_write): For large segment count,
write PN_XNUM to e_phnum field.
* arm.cc (map, utility): Include headers.
(Target_arm::apply_cortex_a8_workaround): New method.
(Arm_relobj::do_relocate_sections): Apply any Cortex-A8 workaround.
(Target_arm::Scan::local): Handle R_ARM_THM_JUMP24, R_ARM_THM_JUMP19.
(Target_arm::Scan::global): R_ARM_THM_JUMP19.
(Target_arm::do_finalize_sections): Set fix_cortex_a8_ according to
the --[no-]fix-cortex-a8 command line options.
(Target_arm::Relocate::relocate): Handle R_ARM_JUMP19.
(Target_arm::relocate_stub): Use addend in instruction template.
* options.h (DEFINE_bool): Set the user-set flag.
(General_options): Add --[no-]-fix-cortex options.
* output.cc (Output_section::convert_input_sections_to_relaxed_sections)
: Update fast look-up map after conversion.
* arm.cc (Arm_relobj::section_needs_reloc_stub_scanning,
Arm_relobj::scan_sections_for_stubs): Rearrange code to avoid an
apparent compiler problem of not folding static constant integral
data members of elfcpp::Elf_sizes<32>.
* arm.cc (Arm_relobj::section_needs_reloc_stub_scanning,
Arm_relobj::section_needs_cortex_a8_stub_scanning,
Arm_relobj::scan_section_for_cortex_a8_erratum,
Arm_relobj::scan_span_for_cortex_a8_erratum): New methods.
(Arm_relobj::scan_sections_for_stubs): Move code deciding what
sections to scan for relocation stubs into a new method
Arm_relobj::section_needs_reloc_stub_scanning. Handle both
relocation and Cortex-A8 stub scanning.
(Target_arm::do_relax): Force stubs to be after stubbed sections
if fixing the Cortex-A8 erratum. Remove all Cortex-A8 stubs at
the beginning of a new relaxation pass. Update a comment.
(Target_arm::scan_span_for_cortex_a8_erratum): New method definition.
