* 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.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::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.
* arm.cc (Arm_relobj::do_gc_process_relocs): New method.
(Target_arm::do_finalize_sections): Define special EXIDX section
symbols only if referenced.
* gc.h (Garbage_collection::add_reference): New method.
(gc_process_relocs): Use Garbage_collection::add_reference to avoid
code duplication.
(Garbage_collection::cident_sections): New function.
(Garbage_collection::add_cident_section): New function.
(Garbage_collection::cident_sections_): New member.
(gc_process_relocs): Add references to sections whose names are C
identifiers.
* gold.h (cident_section_start_prefix): New constant.
(cident_section_stop_prefix): New constant.
(is_cident): New function.
* layout.cc (Layout::define_section_symbols): Replace string constants
with the newly defined constants.
* object.cc (Sized_relobj::do_layout): Track sections whose names are
C identifiers.
* testsuite/Makefile.am: Add gc_orphan_section_test.
* testsuite/Makefile.in: Regenerate.
* testsuite/gc_orphan_section_test.cc: New file.
* testsuite/gc_orphan_section_test.sh: New file.
check for .text or .gnu.linkonce.t sections.
* icf.cc (Icf::find_identical_sections): Ditto.
Change the detection for mangled function name within the section
name.
* icf.h (is_section_foldable_candidate): New function.
function.
* gold.cc (queue_initial_tasks): Likewise.
(queue_middle_tasks): Likewise.
* object.cc (do_layout): Likewise.
* symtab.cc (is_section_folded): Likewise.
* main.cc (main): Likewise.
* reloc.cc (Read_relocs::run): Likewise.
(Sized_relobj::do_scan_relocs): Likewise.
* icf.cc (is_function_ctor_or_dtor): New function.
(Icf::find_identical_sections): Check if function is ctor or dtor when
safe icf is chosen.
* options.h (General_options::icf): Change option to be an enum.
(Icf_status): New enum.
(icf_enabled): New method.
(icf_safe_folding): New method.
(set_icf_status): New method.
(icf_status_): New variable.
* (options.cc) (General_options::finalize): Set icf_status_.
* testsuite/Makefile.am: Add commands to build icf_safe_test. Modify
icf_test and icf_keep_unique_test to use the --icf enum flag.
* testsuite/icf_safe_test.sh: New file.
* testsuite/icf_safe_test.cc: New file.
* Makefile.am (CCFILES): Add gc.cc.
(HFILES): Add gc.h.
* Makefile.in: Regenerate.
* gold.cc (Gc_runner): New class.
(queue_initial_tasks): Call garbage collection related tasks
when corresponding options are invoked.
(queue_middle_gc_tasks): New function.
(queue_middle_tasks): Reorder tasks to allow relocs to be read and
processed early before laying out sections during garbage collection.
* gold.h (queue_middle_gc_tasks): New function.
(is_prefix_of): Move from "layout.cc".
* i386.cc (Target_i386::gc_process_relocs): New function.
* layout.cc (is_prefix_of): Remove. Move to "gold.h"
* main.cc (main): Create object of class "Garbage_collection".
* object.cc (Relobj::copy_symbols_data): New function.
(Relobj::is_section_name_included): New function.
(Sized_relobj::do_layout): Allow this function to be called twice
during garbage collection and defer layout of section during the
first call.
* object.h (Relobj::get_symbols_data): New function.
(Relobj::is_section_name_included): New function.
(Relobj::copy_symbols_data): New function.
(Relobj::set_symbols_data): New function.
(Relobj::get_relocs_data): New function.
(Relobj::set_relocs_data): New function.
(Relobj::is_output_section_offset_invalid): New pure virtual function.
(Relobj::gc_process_relocs): New function.
(Relobj::do_gc_process_relocs): New pure virtual function.
(Relobj::sd_): New data member.
(Sized_relobj::is_output_section_offset_invalid): New function.
(Sized_relobj::do_gc_process_relocs): New function.
* options.h (General_options::gc_sections): Modify to not be a no-op.
(General_options::print_gc_sections): New option.
* plugin.cc (Plugin_finish::run): Remove function call to
Plugin_manager::layout_deferred_objects. Move it to "gold.cc".
* powerpc.cc (Target_powerpc::gc_process_relocs): New function.
* reloc.cc (Read_relocs::run): Add task to process relocs and
determine unreferenced sections when doing garbage collection.
(Gc_process_relocs): New class.
(Sized_relobj::do_gc_process_relocs): New function.
(Sized_relobj::do_scan_relocs): Don't try to scan the relocs for
sections that are garbage collected.
* reloc.h (Gc_process_relocs): New class.
* sparc.cc (Target_sparc::gc_process_relocs): New function.
* symtab.cc (Symbol::should_add_dynsym_entry): Do not add entries for
symbols whose corresponding sections are garbage collected.
(Symbol_table::Symbol_table): Add new parameter for the garbage
collection object.
(Symbol_table::gc_mark_undef_symbols): New function.
(Symbol_table::gc_mark_symbol_for_shlib): New function.
(Symbol_table::gc_mark_dyn_syms): New function.
(Symbol_table::resolve): Do not treat symbols seen in dynamic objects
as garbage.
(Symbol_table::add_from_object): Likewise.
(Symbol_table::add_from_relobj): When building shared objects, do not
treat externally visible symbols as garbage.
(Symbol_table::sized_finalize_symbol): Do not check dynamic symbol
table information for static and relocatable links.
* symtab.h (Symbol_table::set_gc): New function.
(Symbol_table::gc): New function.
(Symbol_table::gc_mark_undef_symbols): New function.
(Symbol_table::gc_mark_symbol_for_shlib): New function.
(Symbol_table::gc_mark_dyn_syms): New function.
(Symbol_table::gc_): New data member.
* target.h (Sized_target::gc_process_relocs): New pure virtual
function.
* x86_64.cc (Target_x86_64::gc_process_relocs): New function.
* testsuite/testfile.cc (Target_test::gc_process_relocs): New function.
