(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.
* common.cc (Sort_commons::operator()): Stabilize sort when both
entries are NULL.
(Symbol_table::do_allocate_commons_list): When allocating common
symbols, skip a symbol which is no longer common.
* symtab.h (Symbol::is_common): Test whether the symbol comes from
an object before checking its type.
* testsuite/common_test_2.c: New file.
* testsuite/common_test_3.c: New file.
* testsuite/Makefile.am (check_PROGRAMS): Add common_test_2.
(common_test_2_SOURCES, common_test_2_DEPENDENCIES): Define.
(common_test_2_LDFLAGS, common_test_2_LDADD): Define.
(common_test_2_pic.o, common_test_2.so): New targets.
(common_test_3_pic.o, common_test_3.so): New targets.
* testsuite/Makefile.in: Rebuild.
* symtab.cc (Symbol_table::add_from_relobj): When not exporting
symbols from this object, don't change the visibility of an
undefined symbol.
* testsuite/exclude_libs_test_1.c (lib1_ref): New function.
* script.h (class Version_script_info): Define Language enum.
Update declarations. Define Glob, Exact, and Lookup types. Add
new fields globals_, locals_, and is_finalized_.
* script.cc: Various formatting fixes.
(class Parser_closure): Change language_stack_ from a vector of
std::string to one of Version_script_info::Language. Adjust all
uses accordingly.
(class Lazy_demangler): Remove.
(struct Version_expression): Change language from std::string to
Version_script_info::Language.
(Version_script_info::Version_script_info): New function.
(Version_script_info::~Version_script_info): Don't call clear.
(Version_script_info::finalize): New function.
(Version_script_info::build_lookup_tables): New function.
(Version_script_info::build_expression_list_lookup): New
function.
(Version_script_info::get_symbol_version_helper): Rewrite to use
lookup tables.
(Version_script_info::print_expression_list): Adjust to use
Version_script_info::Language.
(script_push_lex_into_version_mode): Check that the version script
has not been finalized.
(version_script_push_lang): Change language string to
Version_script_info::Language.
* options.cc (Command_line::version_script): New function.
* options.h (class General_options): Add finalize_dynamic_list
function. Change version_script from declaration to definition.
* testsuite/ver_test_4.script: Remove duplicate def of t2_2.
* testsuite/version_script.map: Remove duplicate def of foo.
* testsuite/Makefile.am (ver_matching_def.so): Depend upon
version_script.map.
* testsuite/Makefile.in: Rebuild.
* dynobj.cc (Versions::Versions): Initialize version_script_.
Only insert base version symbol definition for a shared object
if version script defines any version versions.
(Versions::define_base_version): New method definition.
(Versions::add_def): Check that base version is not needed.
(Versions::add_need): Define base version lazily.
* dynobj.h (Versions::define_base_version): New method declaration.
(Versions::needs_base_version_): New data member declaration.
* testsuite/Makefile.am (check_SCRIPTS): Add no_version_test.sh
(check_DATA): Add no_version_test.stdout.
(libno_version_test.so, no_version_test.o no_version_test.stdout):
New make rules.
* testsuite/Makefile.in: Regenerate.
* testsuite/no_version_test.c: New file.
* testsuite/no_version_test.sh: Ditto.
* expression.cc (class Segment_start_expression): New class definition.
(Segment_start_expression::value): New method definition.
(script_exp_function_segment_start): Return a new
Segment_start_expression.
* gold/script-c.h (script_saw_segment_start_expression): New function
prototype.
* script-sections.cc (Script_sections::Script_sections): Initialize
SAW_SEGMENT_START_EXPRESSION_ to false.
(Script_sections::set_section_addresses): Use -Ttext, -Tdata
and -Tbbs options to specify section addresses if given in
command line and no SEGMENT_START expression is seen in a script.
* script-sections.h (Script_sections::saw_segment_start_expression,
Script_sections::set_saw_segment_start_expression): New method
definition.
(Script_sections::saw_segment_start_expression_): New data member
declaration.
* script.cc (script_saw_segment_start_expression): New function.
* yyscript.y (SEGMENT_START): Call script_saw_segment_start_expression.
* testsuite/Makefile.am (check_SCRIPTS): Add script_test_6.sh,
script_test_7.sh and script_test_8.sh.
(check_DATA): Add script_test_6.stdout, script_test_7.stdout and
script_test_8.stdout.
(MOSTLYCLEANFILES): Add script_test_6, script_test_7 and script_test_8.
(script_test_6, script_test_6.stdout, script_test_7,
script_test_7.stdout, script_test_8, script_test_8.stdout): New rules.
* Makefile.in: Regenerate.
* testsuite/script_test_6.sh: New file.
* testsuite/script_test_6.t: Same.
* testsuite/script_test_7.sh: Same.
* testsuite/script_test_7.t: Same.
* testsuite/script_test_8.sh: Same.
* options.h (class General_options): Add -pie and
--pic-executable.
(General_options::output_is_position_independent): Test -pie.
(General_options::output_is_executable): Return true if not shared
and not relocatable.
(General_options::output_is_pie): Remove.
* options.cc (General_options::finalize): Reject incompatible uses
of -pie.
* gold.cc (queue_middle_tasks): A -pie link is not static.
* symtab.h (Symbol::needs_plt_entry): Return false if -pie.
* symtab.cc (Symbol::final_value_is_known): Return false if
output_is_position_independent.
* layout.cc (Layout::set_segment_offsets): Start at address 0 if
output_is_position_independent.
* output.cc (Output_file_header::do_sized_write): Use ET_DYN if
output_is_position_independent.
* i386.cc (Output_data_plt_i386::do_write): Use the PIC PLT if
output_is_position_independent.
* testsuite/Makefile.am (check_PROGRAMS): Add basic_pie_test and
two_file_pie_test.
(basic_pie_test.o, basic_pie_test): New targets.
(two_file_test_1_pie.o, two_file_test_1b_pie.o): New targets.
(two_file_test_2_pie.o, two_file_test_main_pie.o): New targets.
(two_file_pie_test): New target.
* testsuite/Makefile.in: Rebuild.
* README: Remove note saying that -pie is not supported.
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.
* options.cc: Include <cerrno> and <fstream>.
(General_options::finalize): Parse -retain-symbols-file tag.
* options.h: New flag.
(General_options): New method should_retain_symbol, new
variable symbols_to_retain.
* symtab.cc (Symbol_table::sized_finalize_symbol): Test
should_retain_symbol map.
* testsuite/Makefile.am (retain_symbols_file_test): New test.
* testsuite/Makefile.in: Regenerate.
* testsuite/retain_symbols_file_test.sh: New file.
ld/:
* Makefile.am (bin_PROGRAMS): Renamed from ...
(noinst_PROGRAMS): ... this.
(transform): Override, including the renaming of ld-new to ld.
(install-exec-local): Installation of ld in $(bindir) not needed
here any more.
(AM_CPPFLAGS): Renamed from ...
(INCLUDES): ... this.
(MAINTAINERCLEANFILES): Add ld.1.
* Makefile.in: Regenerate.
gold/:
* Makefile.am (AM_CPPFLAGS): Renamed from ...
(INCLUDES): ... this.
* testsuite/Makefile.am (AUTOMAKE_OPTIONS): Add -Wno-portability.
(AM_CPPFLAGS): Renamed from ...
(INCLUDE): ... this.
* Makefile.in, testsuite/Makefile.in: Regenerate.
bfd/:
* Makefile.am (libbfd_la_LDFLAGS): Initialize early, to allow
appending.
[INSTALL_LIBBFD] (bfdlib_LTLIBRARIES, bfdinclude_HEADERS): Set
only in this condition.
[!INSTALL_LIBBFD] (noinst_LTLIBRARIES, libbfd_la_LDFLAGS): New,
to build but not install libbfd.la in this condition.
(install-bfdlibLTLIBRARIES, uninstall-bfdlibLTLIBRARIES)
(install_libbfd, install_libbfd): Remove.
* Makefile.in: Regenerate.
binutils/:
* Makefile.am (AM_CPPFLAGS): Renamed from ...
(INCLUDES): ... this.
(bin2c$(EXEEXT_FOR_BUILD): Adjust rule.
(installcheck-local): Renamed from ...
(installcheck): ... this.
* Makefile.in: Regenerate.
gas/:
* Makefile.am (YFLAGS): Remove, not needed any more.
(AM_CPPFLAGS): Renamed from ...
(INCLUDES): ... this.
* Makefile.in: Regenerate.
gprof/:
* Makefile.am (AM_CPPFLAGS): Renamed from ...
(INCLUDES): ... this.
* Makefile.in: Regenerate.
opcodes/:
* Makefile.am (libopcodes_la_LDFLAGS): Initialize early.
[INSTALL_LIBBFD] (bfdlib_LTLIBRARIES): Set only in this condition.
[INSTALL_LIBBFD] (bfdinclude_DATA): New.
[!INSTALL_LIBBFD] (noinst_LTLIBRARIES): New.
[!INSTALL_LIBBFD] (libopcodes_la_LDFLAGS): Ensure libopcodes.la
is built shared even if it is not to be installed.
(install-bfdlibLTLIBRARIES,uninstall-bfdlibLTLIBRARIES)
(install_libopcodes, uninstall_libopcodes): Remove.
(AM_CPPFLAGS): Renamed from ...
(INCLUDES): ... this.
* Makefile.in: Regenerate.
* icf.cc (Icf::find_identical_sections): Unfold symbols that have
been maked as --keep-unique.
(Icf::unfold_section): New function.
* icf.h (Icf::unfold_section): New function.
* options.h (General_options::keep_unique): New option.
* testsuite/Makefile.am: Add commands to build icf_keep_unique_test.
* testsuite/Makefile.in: Regenerate.
* testsuite/icf_keep_unique_test.sh: New file.
* testsuite/icf_keep_unique_test.cc: New file.
* resolve.cc (Symbol_table::resolve): Check for references from
dynamic objects to hidden and internal symbols.
* testsuite/Makefile.am (hidden_test.sh): New test.
* testsuite/Makefile.in: Regenerate.
* testsuite/hidden_test.sh: New script.
* testsuite/hidden_test_1.c: New test source.
* testsuite/hidden_test_main.c: New test source.
Target::new_output_section.
(Layout::attach_allocated_section_to_segment): Put large section
sections in a separate load segment with the large segment flag
set.
(Layout::segment_precedes): Sort large data segments after other
load segments.
(align_file_offset): New static function.
(Layout::set_segment_offsets): Use align_file_offset.
* output.h (class Output_section): Add is_small_section_ and
is_large_section_ fields.
(Output_section::is_small_section): New function.
(Output_section::set_is_small_section): New function.
(Output_section::is_large_section): New function.
(Output_section::set_is_large_section): New function.
(Output_section::is_large_data_section): New function.
(class Output_segment): Add is_large_data_segment_ field.
(Output_segment::is_large_data_segment): New function.
(Output_segment::set_is_large_data_segment): New function.
* output.cc (Output_section::Output_section): Initialize new
fields.
(Output_segment::Output_segment): Likewise.
(Output_segment::add_output_section): Add assertion that large
data sections always go in large data segments. Force small data
sections to the end of the list of data sections. Force small BSS
sections to the start of the list of BSS sections. For large BSS
sections to the end of the list of BSS sections.
* symtab.h (class Symbol): Declare is_common_shndx.
(Symbol::is_defined): Check Symbol::is_common_shndx.
(Symbol::is_common): Likewise.
(class Symbol_table): Define enum Commons_section_type. Update
declarations. Add small_commons_ and large_commons_ fields.
* symtab.cc (Symbol::is_common_shndx): New function.
(Symbol_table::Symbol_table): Initialize new fields.
(Symbol_table::add_from_object): Put small and large common
symbols in the right list.
(Symbol_table::sized_finalized_symbol): Check
Symbol::is_common_shndx.
(Symbol_table::sized_write_globals): Likewise.
* common.cc (Symbol_table::do_allocate_commons): Allocate new
common symbol lists. Don't call do_allocate_commons_list if the
list is empty.
(Symbol_table::do_allocate_commons_list): Remove is_tls
parameter. Add comons_section_type parameter. Change all
callers. Handle small and large common symbols.
* object.cc (Sized_relobj::do_finalize_local_symbols): Check
Symbol::is_common_shndx.
* resolve.cc (symbol_to_bits): Likewise.
* target.h (Target::small_common_shndx): New function.
(Target::small_common_section_flags): New function.
(Target::large_common_shndx): New function.
(Target::large_common_section_flags): New function.
(Target::new_output_section): New function.
(Target::Target_info): Add small_common_shndx, large_common_shndx,
small_common_section_flags, and large_common_section_flags
fields.
(Target::do_new_output_section): New virtual function.
* arm.cc (Target_arm::arm_info): Initialize new fields.
* i386.cc (Target_i386::i386_info): Likewise.
* powerpc.cc (Target_powerpc::powerpc_info) [all versions]:
Likewise.
* sparc.c (Target_sparc::sparc_info) [all versions]: Likewise.
* x86_64.cc (Target_x86_64::x86_64_info): Likewise.
(Target_x86_64::do_new_output_section): New function.
* configure.ac: Define conditional MCMODEL_MEDIUM.
* testsuite/Makefile.am (check_PROGRAMS): Add large.
(large_SOURCES, large_CFLAGS, large_DEPENDENCIES): Define.
(large_LDFLAGS): Define.
* testsuite/large.c: New file.
* testsuite/testfile.cc (Target_test::test_target_info):
Initialize new fields.
* configure, testsuite/Makefile.in: Rebuild.
* object.cc (Sized_relobj::Sized_relobj): Initialize
discarded_eh_frame_shndx_ to -1U.
(Sized_relobj::do_layout): Record index of a discard .eh_frame
section.
(Sized_relobj::do_count_local_symbols): Skip local symbols in
a discarded .eh_frame section.
(Sized_relobj::do_finalize_local_symbols): Ditto.
* object.h (class Sized_relobj): Declare new member
discarded_eh_frame_shndx_.
* testsuite/Makefile.am (check_PROGRAMS): Add local_labels_test.
(local_labels_test.o, local_labels_test): New rules.
* testsuite/Makefile.in: Regenerate.
* options.cc (General_options::parse_exclude_libs). Fix a comment.
(General_options::check_excluded_libs): Strip off directories in
archive name before matching like GNU ld does.
* testsuite/Makefile.am (MOSTLYCLEANFILES,
exclude_libs_test_DEPENDENCIES): Add alt/libexclude_libs_test_3.a
(exclude_libs_test_LDFLAGS): Add linker option
-Wl,--exclude-libs,libexclude_libs_test_3
(exclude_libs_test_LADD): Add alt/libexclude_libs_test_3.a as
an explicit archive without using -l.
(alt/libexclude_libs_test_3.a): New make rule.
* testsuite/Makefile.in: Regenerate.
* testsuite/exclude_libs_test.c : Declare lib3_default().
(main): Call it.
* exclude_libs_test.sh: Add tests for alt/exclude_libs_test_3.a.
* exclude_libs_test_3.c: New file.
* archive.cc (Archive::Archive): Move constructor from archive.h
to here. Initialize no_export_.
(Archive::get_elf_object_for_member): Set no_export flag of object.
* archive.h (Archive::Archive): Move constructor body to
archive.cc.
(Archive::no_export): New method.
(Archive::no_export_): New field.
* object.h (Object::Object): Initialize no_export_ to false.
(Object::no_export, Object::set_no_export): New methods.
(Object::no_export_): New field.
* options.cc (General_options::parse_exclude_libs): New method.
(General_options::check_excluded_libs) Same.
* options.h (exclude_libs): New option.
(General_options::check_excluded_libs): New method declaration.
(General_options::excluded_libs_): New field.
* symtab.cc (Symbol_table::add_from_relobj): Hide symbols with
default or protected visibility if an object has no-export flag set.
testsuite/Makefile.am (check_PROGRAMS): Add exclude_libs_test.
(check_SCRIPTS): Add exclude_libs_test.sh.
(check_DATA): Add exclude_libs_test.syms.
(MOSTLYCLEANFILES): Add exclude_libs_test.syms,
libexclude_libs_test_1.a and libexclude_libs_test_2.a.
(exclude_libs_test_SOURCES, exclude_libs_test_DEPENDENCIES,
exclude_libs_test_LDFLAGS and exclude_libs_test_LDADD): Define.
(exclude_libs_test.syms, libexclude_libs_test_1.a,
libexclude_libs_test_2.a): New rules.
* testsuite/Makefile.in: Regenerate.
* testsuite/exclude_libs_test.c: New file.
* testsuite/exclude_libs_test.sh: Ditto.
* testsuite/exclude_libs_test_1.c: Ditto.
* testsuite/exclude_libs_test_2.c: Ditto.
to the symbol name in the archive map.
* testsuite/Makefile.am (check_PROGRAMS): Add ver_test_11.
(ver_test_11_SOURCES, ver_test_11_DEPENDENCIES): Define.
(ver_test_11_LDFLAGS, ver_test_11_LDADD): Define.
(ver_test_11.a): New target.
* testsuite/Makefile.in: Rebuild.
(Read_symbols::requeue): New function.
(Read_symbols::do_read_symbols): If make_elf_object fails because
the target type is not configured, and the file was searched for,
issue a warning and retry with the next directory.
(Add_symbols::run): If the file has an incompatible format, and
it was searched for, requeue the Read_symbols task. On error,
release the object.
* readsyms.h (class Read_symbols): Add dirindex_ field. Add
dirindex parameter to constructor. Change all callers. Declare
incompatible_warning and requeue.
(class Add_symbols): Add dirpath_, dirindex_, mapfile_,
input_argument_ and input_group_ fields. Add them to
constructor. Change all callers.
(class Read_script): Add dirindex_ field. Add it to constructor.
Change all callers.
* archive.cc (Archive::setup): Remove input_objects parameter.
Change all callers.
(Archive::get_file_and_offset): Likewise.
(Archive::read_all_symbols): Likewise.
(Archive::read_symbols): Likewise.
(Archive::get_elf_object_for_member): Remove input_objects
parameter. Add punconfigured parameter. Change all callers.
(Archive::add_symbols): Change return type to bool. Check return
value of include_member.
(Archive::include_all_members): Likewise.
(Archive::include_member): Change return type to bool. Return
false if first included object has incompatible target. Set
included_member_ field.
(Add_archive_symbols::run): If add_symbols returns false, requeue
Read_symbols task.
* archive.h (class Archive): Add included_member_ field.
Initialize it in constructor. Add input_file and searched_for
methods. Update declarations.
(class Add_archive_symbols): Add dirpath_, dirindex_, and
input_argument_ fields. Add them to constructor. Change all
callers.
* script.cc: Include "target-select.h".
(class Parser_closure): Add skip_on_incompatible_target_ and
found_incompatible_target_ fields. Add
skip_on_incompatible_target parameter to constructor. Change all
callers. Add methods skip_on_incompatible_target,
clear_skip_on_incompatible_target, found_incompatible_target, and
set_found_incompatible_target.
(read_input_script): Add dirindex parameter. Change all callers.
If parser finds an incompatible target, requeue Read_symbols
task.
(script_set_symbol): Clear skip_on_incompatible_target in
closure.
(script_add_assertion, script_parse_option): Likewise.
(script_start_sections, script_add_phdr): Likewise.
(script_check_output_format): New function.
* script.h (read_input_script): Update declaration.
* script-c.h (script_check_output_format): Declare.
* yyscript.y (file_cmd): Handle OUTPUT_FORMAT.
(ignore_cmd): Remove OUTPUT_FORMAT.
* fileread.cc (Input_file::Input_file): Add explicit this.
(Input_file::will_search_for): New function.
(Input_file::open): Add pindex parameter. Change all callers.
* fileread.h (class Input_file): Add input_file_argument method.
Declare will_search_for. Update declarations.
* object.cc (make_elf_object): Add punconfigured parameter.
Change all callers.
* object.h (class Object): Make input_file public. Add
searched_for method.
(make_elf_object): Update declaration.
* dirsearch.cc (Dirsearch::find): Add pindex parameter. Use it to
restart search.
* dirsearch.h (class Dirsearch): Update declaration.
* options.h (class General_options): Add --warn-search-mismatch.
* parameters.cc (Parameters::is_compatible_target): New function.
* parameters.h (class Parameters): Declare is_compatible_target.
* workqueue.cc (Workqueue::add_blocker): New function.
* workqueue.h (class Workqueue): Declare add_blocker.
* symtab.cc (Symbol_table::add_from_object): If the visibility is
hidden or internal, force the symbol to be local.
* resolve.cc (Symbol::override_visibility): Define.
(Symbol::override_base): Use override_visibility.
(Symbol_table::resolve): Likewise.
(Symbol::override_base_with_special): Likewise.
(Symbol_table::override_with_special): If the visibility is hidden
or internal, force the symbol to be local.
* symtab.h (class Symbol): Add set_visibility and
override_visibility.
* testsuite/ver_test_1.sh: New file.
* testsuite/Makefile.am (check_SCRIPTS): Add ver_test_1.sh.
(check_DATA): Add ver_test_1.syms.
(ver_test_1.syms): New target.
* testsuite/Makefile.in: Rebuild.
when using a linker script that has a SECTIONS clause.
* Makefile.in: Regenerate.
* testsuite/Makefile.am (script_test_5.sh): New test case.
* testsuite/Makefile.in: Regenerate.
* testsuite/script_test_5.cc: New file.
* testsuite/script_test_5.sh: New file.
* testsuite/script_test_5.t: New file.
* gold.h (gold_undefined_symbol): Change to take only a Symbol
pointer and to report location as the file name associated with
the symbol.
(gold_undefined_symbol_at_location): New function to replace the
old gold_undefined_symbol functionality.
* target-reloc.h (relocate_section): Update to use
gold_undefined_symbol_at_location.
* symtab.cc (Symbol_table::warn_about_undefined_dynobj_symbol):
Call gold_undefined_symbol function rather than gold_error.
* errors.h (Errors::undefined_symbol): Take location as a
string, rather than calculating it from a relocation.
* errors.cc (Errors::fatal): Print "fatal error:" before the
formatted message.
(Errors::error, Errors::error_at_location): Print "error: "
before the formatted message.
(Errors::undefined_symbol): Take location as a string, rather
than calculating it from a relocation.
(gold_undefined_symbol_at_location): New function akin to
old gold_undefined_symbol, calculates location from relocation.
(gold_undefined_symbol): Change to take only a Symbol pointer
and to report location as the file name associated with the symbol.
* testsuite/debug_msg.sh: Update for changed error messages.
* testsuite/undef_symbol.sh: Likewise.
* 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.