Add tls support to gold aarch64 backend.

Add tls support to gold aarch64 backend.

elfcpp/ChangeLog:
2014-09-17  Han Shen  <shenhan@google.com>
	* aarch64.h (R_AARCH64_TLS_DTPREL64): Switch enum value with ...
	(R_AARCH64_TLS_DTPMOD64): ... enum value.

gold/ChangeLog:
2014-09-17  Han Shen  <shenhan@google.com>
	    Jing Yu  <jingyu@google.com>
        * aarch64-reloc.def: Add TLSGD_ADR_PAGE21, TLSGD_ADD_LO12_NC,
        TLSDESC_ADR_PAGE21, TLSDESC_LD64_LO12, TLSDESC_ADD_LO12, TLSDESC_CALL.
        * aarch64.cc (Target_aarch64): Add data members
        got_irelative_, got_tlsdesc_, rela_irelative_, got_mod_index_offset_,
        tlsdesc_reloc_info_, tls_base_symbol_defined_. Initialize them in
        constructor.
        (Target_aarch64::do_reloc_symbol_index): New method.
        (Target_aarch64::do_reloc_addend): New method.
        (Target_aarch64::add_tlsdesc_info): New method.
        (Target_aarch64::do_dynsym_value): New method.
        (Target_aarch64::do_make_data_plt): Add new parameters: got,
        got_irelative. Pass them to Output_data_plt_aarch64_standard.
        (Target_aarch64::make_data_plt): Add new parameters: got,
        got_irelative. Pass them to do_make_data_plt.
        (Target_aarch64::Relocate): Add skip_call_tls_get_addr_ variable.
        (Target_aarch64::Relocate:tls_gd_to_le): New method.
        (Target_aarch64::Relocate:tls_ie_to_le): New method.
        (Target_aarch64::Relocate:tls_desc_gd_to_le): New method.
        (Target_aarch64::Relocate:tls_desc_gd_to_ie): New method.
        (Target_aarch64::got_tlsdesc_section): New method.
        (Target_aarch64::make_local_ifunc_plt_entry): New method.
        (Target_aarch64::define_tls_base_symbol): New method.
        (Target_aarch64::reserve_tlsdesc_entries): New method.
        (Target_aarch64::got_mod_index_entry): New method.
        (Target_aarch64::rela_tlsdesc_section): New method.
        (Target_aarch64::rela_irelative_section): New method.
        (Target_aarch64::Tlsdesc_info): New struct.
        (Target_aarch64::got_section): Create .got.plt space for IRELATIVE
        relocations and tlsdesc relocations.
        (Target_aarch64::optimize_tls_reloc): Implement method.
        (Output_data_plt_aarch64): Add member variables: tlsdesc_rel_, got_,
        got_irelative_, irelative_count_, tlsdesc_got_offset_. Initialize them
        in constructor.
        (Output_data_plt_aarch64::reserve_tlsdesc_entry): New method.
        (Output_data_plt_aarch64::has_tlsdesc_entry): New method.
        (Output_data_plt_aarch64::get_tlsdesc_got_offset): New method.
        (Output_data_plt_aarch64::get_tlsdesc_plt_offset): New method.
        (Output_data_plt_aarch64::rela_tlsdesc): New method.
        (Output_data_plt_aarch64::rela_irelative): New method.
        (Output_data_plt_aarch64::entry_count): Count IRELATIVE relocations.
        (Output_data_plt_aarch64::first_plt_entry_offset): Add const attribute.
        (Output_data_plt_aarch64::get_plt_tlsdesc_entry_size): New method.
        (Output_data_plt_aarch64::fill_tlsdesc_entry): New method.
        (Output_data_plt_aarch64::do_get_plt_tlsdesc_entry_size): New method.
        (Output_data_plt_aarch64::do_fill_tlsdesc_entry): New method.
        (Output_data_plt_aarch64_standard): New member variables:
        plt_tlsdesc_entry_size, tlsdesc_plt_entry.
        (Output_data_plt_aarch64_standard::Output_data_plt_aarch64_standard):
        New parameter: got, got_irelative.
        (Output_data_plt_aarch64_standard::do_get_plt_entry_size): New method.
        (Output_data_plt_aarch64_standard::do_fill_tlsdesc_entry): New method.
        (Output_data_plt_aarch64::do_write): Replace got_address with
        gotplt_address. Add irelative_count_ to count. Write tlsdesc entry.
        (AArch64_relocate_functions::update_movnz): New method.
        (AArch64_relocate_functions): Correct format.
        (AArch64_relocate_functions::movnz): New method.
        (Target_aarch64::Scan::local): Correct format. Move r_sym, got to
        before the switch. Add new cases to switch.
        Check ie_to_le relaxation on tlsie relocations. Add code handling
        tlsgd tlsdesc cases.
        (Target_aarch64::Scan::global): Move arp to front. Do copy_reloc when
        needed. Add new cases to switch. Insert dynamic RELATIVE relocation
        when needed. Add code handling tlsgd, tlsie, tlsdesc cases.
        Call reloc_name_in_error_message to print unsupported reloc.
        (Target_aarch64::make_plt_section): Pass got_ and got_irelative_ to
        make_data_plt.
        (Target_aarch64::do_finalize_sections): Emit relocs to save COPY
        relocs. Fill in some more dynamic tags.
        (Target_aarch64::Relocate::relocate): Handle tlsgd, tlsdesc relocs.
        Skip call tls_get_addr when tlsgd is relaxed.
        (Target_aarch64::Relocate::relocate_tls): Correct format. Add code
        handling tlsgd, tlsdesc relocs, and tls gd->le, ie->le, tlsdesc->le,
        tlsdesc->ie relaxation.