| // x86_64.cc -- x86_64 target support for gold. |
| |
| // Copyright (C) 2006-2024 Free Software Foundation, Inc. |
| // Written by Ian Lance Taylor <iant@google.com>. |
| |
| // This file is part of gold. |
| |
| // This program is free software; you can redistribute it and/or modify |
| // it under the terms of the GNU General Public License as published by |
| // the Free Software Foundation; either version 3 of the License, or |
| // (at your option) any later version. |
| |
| // This program is distributed in the hope that it will be useful, |
| // but WITHOUT ANY WARRANTY; without even the implied warranty of |
| // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| // GNU General Public License for more details. |
| |
| // You should have received a copy of the GNU General Public License |
| // along with this program; if not, write to the Free Software |
| // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, |
| // MA 02110-1301, USA. |
| |
| #include "gold.h" |
| |
| #include <cstring> |
| |
| #include "elfcpp.h" |
| #include "dwarf.h" |
| #include "parameters.h" |
| #include "reloc.h" |
| #include "x86_64.h" |
| #include "object.h" |
| #include "symtab.h" |
| #include "layout.h" |
| #include "output.h" |
| #include "copy-relocs.h" |
| #include "target.h" |
| #include "target-reloc.h" |
| #include "target-select.h" |
| #include "tls.h" |
| #include "freebsd.h" |
| #include "nacl.h" |
| #include "gc.h" |
| #include "icf.h" |
| |
| namespace |
| { |
| |
| using namespace gold; |
| |
| // A class to handle the .got.plt section. |
| |
| class Output_data_got_plt_x86_64 : public Output_section_data_build |
| { |
| public: |
| Output_data_got_plt_x86_64(Layout* layout) |
| : Output_section_data_build(8), |
| layout_(layout) |
| { } |
| |
| Output_data_got_plt_x86_64(Layout* layout, off_t data_size) |
| : Output_section_data_build(data_size, 8), |
| layout_(layout) |
| { } |
| |
| protected: |
| // Write out the PLT data. |
| void |
| do_write(Output_file*); |
| |
| // Write to a map file. |
| void |
| do_print_to_mapfile(Mapfile* mapfile) const |
| { mapfile->print_output_data(this, "** GOT PLT"); } |
| |
| private: |
| // A pointer to the Layout class, so that we can find the .dynamic |
| // section when we write out the GOT PLT section. |
| Layout* layout_; |
| }; |
| |
| // A class to handle the PLT data. |
| // This is an abstract base class that handles most of the linker details |
| // but does not know the actual contents of PLT entries. The derived |
| // classes below fill in those details. |
| |
| template<int size> |
| class Output_data_plt_x86_64 : public Output_section_data |
| { |
| public: |
| typedef Output_data_reloc<elfcpp::SHT_RELA, true, size, false> Reloc_section; |
| |
| Output_data_plt_x86_64(Layout* layout, uint64_t addralign, |
| Output_data_got<64, false>* got, |
| Output_data_got_plt_x86_64* got_plt, |
| Output_data_space* got_irelative) |
| : Output_section_data(addralign), tlsdesc_rel_(NULL), |
| irelative_rel_(NULL), got_(got), got_plt_(got_plt), |
| got_irelative_(got_irelative), count_(0), irelative_count_(0), |
| tlsdesc_got_offset_(-1U), free_list_() |
| { this->init(layout); } |
| |
| Output_data_plt_x86_64(Layout* layout, uint64_t plt_entry_size, |
| Output_data_got<64, false>* got, |
| Output_data_got_plt_x86_64* got_plt, |
| Output_data_space* got_irelative, |
| unsigned int plt_count) |
| : Output_section_data((plt_count + 1) * plt_entry_size, |
| plt_entry_size, false), |
| tlsdesc_rel_(NULL), irelative_rel_(NULL), got_(got), |
| got_plt_(got_plt), got_irelative_(got_irelative), count_(plt_count), |
| irelative_count_(0), tlsdesc_got_offset_(-1U), free_list_() |
| { |
| this->init(layout); |
| |
| // Initialize the free list and reserve the first entry. |
| this->free_list_.init((plt_count + 1) * plt_entry_size, false); |
| this->free_list_.remove(0, plt_entry_size); |
| } |
| |
| // Initialize the PLT section. |
| void |
| init(Layout* layout); |
| |
| // Add an entry to the PLT. |
| void |
| add_entry(Symbol_table*, Layout*, Symbol* gsym); |
| |
| // Add an entry to the PLT for a local STT_GNU_IFUNC symbol. |
| unsigned int |
| add_local_ifunc_entry(Symbol_table* symtab, Layout*, |
| Sized_relobj_file<size, false>* relobj, |
| unsigned int local_sym_index); |
| |
| // Add the relocation for a PLT entry. |
| void |
| add_relocation(Symbol_table*, Layout*, Symbol* gsym, |
| unsigned int got_offset); |
| |
| // Add the reserved TLSDESC_PLT entry to the PLT. |
| void |
| reserve_tlsdesc_entry(unsigned int got_offset) |
| { this->tlsdesc_got_offset_ = got_offset; } |
| |
| // Return true if a TLSDESC_PLT entry has been reserved. |
| bool |
| has_tlsdesc_entry() const |
| { return this->tlsdesc_got_offset_ != -1U; } |
| |
| // Return the GOT offset for the reserved TLSDESC_PLT entry. |
| unsigned int |
| get_tlsdesc_got_offset() const |
| { return this->tlsdesc_got_offset_; } |
| |
| // Return the offset of the reserved TLSDESC_PLT entry. |
| unsigned int |
| get_tlsdesc_plt_offset() const |
| { |
| return ((this->count_ + this->irelative_count_ + 1) |
| * this->get_plt_entry_size()); |
| } |
| |
| // Return the .rela.plt section data. |
| Reloc_section* |
| rela_plt() |
| { return this->rel_; } |
| |
| // Return where the TLSDESC relocations should go. |
| Reloc_section* |
| rela_tlsdesc(Layout*); |
| |
| // Return where the IRELATIVE relocations should go in the PLT |
| // relocations. |
| Reloc_section* |
| rela_irelative(Symbol_table*, Layout*); |
| |
| // Return whether we created a section for IRELATIVE relocations. |
| bool |
| has_irelative_section() const |
| { return this->irelative_rel_ != NULL; } |
| |
| // Get count of regular PLT entries. |
| unsigned int |
| regular_count() const |
| { return this->count_; } |
| |
| // Return the total number of PLT entries. |
| unsigned int |
| entry_count() const |
| { return this->count_ + this->irelative_count_; } |
| |
| // Return the offset of the first non-reserved PLT entry. |
| unsigned int |
| first_plt_entry_offset() |
| { return this->get_plt_entry_size(); } |
| |
| // Return the size of a PLT entry. |
| unsigned int |
| get_plt_entry_size() const |
| { return this->do_get_plt_entry_size(); } |
| |
| // Reserve a slot in the PLT for an existing symbol in an incremental update. |
| void |
| reserve_slot(unsigned int plt_index) |
| { |
| this->free_list_.remove((plt_index + 1) * this->get_plt_entry_size(), |
| (plt_index + 2) * this->get_plt_entry_size()); |
| } |
| |
| // Return the PLT address to use for a global symbol. |
| uint64_t |
| address_for_global(const Symbol* sym) |
| { return do_address_for_global(sym); } |
| |
| // Return the PLT address to use for a local symbol. |
| uint64_t |
| address_for_local(const Relobj* obj, unsigned int symndx) |
| { return do_address_for_local(obj, symndx); } |
| |
| // Add .eh_frame information for the PLT. |
| void |
| add_eh_frame(Layout* layout) |
| { this->do_add_eh_frame(layout); } |
| |
| protected: |
| Output_data_got<64, false>* |
| got() const |
| { return this->got_; } |
| |
| Output_data_got_plt_x86_64* |
| got_plt() const |
| { return this->got_plt_; } |
| |
| Output_data_space* |
| got_irelative() const |
| { return this->got_irelative_; } |
| |
| // Fill in the first PLT entry. |
| void |
| fill_first_plt_entry(unsigned char* pov, |
| typename elfcpp::Elf_types<size>::Elf_Addr got_address, |
| typename elfcpp::Elf_types<size>::Elf_Addr plt_address) |
| { this->do_fill_first_plt_entry(pov, got_address, plt_address); } |
| |
| // Fill in a normal PLT entry. Returns the offset into the entry that |
| // should be the initial GOT slot value. |
| unsigned int |
| fill_plt_entry(unsigned char* pov, |
| typename elfcpp::Elf_types<size>::Elf_Addr got_address, |
| typename elfcpp::Elf_types<size>::Elf_Addr plt_address, |
| unsigned int got_offset, |
| unsigned int plt_offset, |
| unsigned int plt_index) |
| { |
| return this->do_fill_plt_entry(pov, got_address, plt_address, |
| got_offset, plt_offset, plt_index); |
| } |
| |
| // Fill in the reserved TLSDESC PLT entry. |
| void |
| fill_tlsdesc_entry(unsigned char* pov, |
| typename elfcpp::Elf_types<size>::Elf_Addr got_address, |
| typename elfcpp::Elf_types<size>::Elf_Addr plt_address, |
| typename elfcpp::Elf_types<size>::Elf_Addr got_base, |
| unsigned int tlsdesc_got_offset, |
| unsigned int plt_offset) |
| { |
| this->do_fill_tlsdesc_entry(pov, got_address, plt_address, got_base, |
| tlsdesc_got_offset, plt_offset); |
| } |
| |
| virtual unsigned int |
| do_get_plt_entry_size() const = 0; |
| |
| virtual void |
| do_fill_first_plt_entry(unsigned char* pov, |
| typename elfcpp::Elf_types<size>::Elf_Addr got_addr, |
| typename elfcpp::Elf_types<size>::Elf_Addr plt_addr) |
| = 0; |
| |
| virtual unsigned int |
| do_fill_plt_entry(unsigned char* pov, |
| typename elfcpp::Elf_types<size>::Elf_Addr got_address, |
| typename elfcpp::Elf_types<size>::Elf_Addr plt_address, |
| unsigned int got_offset, |
| unsigned int plt_offset, |
| unsigned int plt_index) = 0; |
| |
| virtual void |
| do_fill_tlsdesc_entry(unsigned char* pov, |
| typename elfcpp::Elf_types<size>::Elf_Addr got_address, |
| typename elfcpp::Elf_types<size>::Elf_Addr plt_address, |
| typename elfcpp::Elf_types<size>::Elf_Addr got_base, |
| unsigned int tlsdesc_got_offset, |
| unsigned int plt_offset) = 0; |
| |
| // Return the PLT address to use for a global symbol. |
| virtual uint64_t |
| do_address_for_global(const Symbol* sym); |
| |
| // Return the PLT address to use for a local symbol. |
| virtual uint64_t |
| do_address_for_local(const Relobj* obj, unsigned int symndx); |
| |
| virtual void |
| do_add_eh_frame(Layout* layout) = 0; |
| |
| void |
| do_adjust_output_section(Output_section* os); |
| |
| // Write to a map file. |
| void |
| do_print_to_mapfile(Mapfile* mapfile) const |
| { mapfile->print_output_data(this, _("** PLT")); } |
| |
| // The CIE of the .eh_frame unwind information for the PLT. |
| static const int plt_eh_frame_cie_size = 16; |
| static const unsigned char plt_eh_frame_cie[plt_eh_frame_cie_size]; |
| |
| private: |
| // Set the final size. |
| void |
| set_final_data_size(); |
| |
| // Write out the PLT data. |
| void |
| do_write(Output_file*); |
| |
| // The reloc section. |
| Reloc_section* rel_; |
| // The TLSDESC relocs, if necessary. These must follow the regular |
| // PLT relocs. |
| Reloc_section* tlsdesc_rel_; |
| // The IRELATIVE relocs, if necessary. These must follow the |
| // regular PLT relocations and the TLSDESC relocations. |
| Reloc_section* irelative_rel_; |
| // The .got section. |
| Output_data_got<64, false>* got_; |
| // The .got.plt section. |
| Output_data_got_plt_x86_64* got_plt_; |
| // The part of the .got.plt section used for IRELATIVE relocs. |
| Output_data_space* got_irelative_; |
| // The number of PLT entries. |
| unsigned int count_; |
| // Number of PLT entries with R_X86_64_IRELATIVE relocs. These |
| // follow the regular PLT entries. |
| unsigned int irelative_count_; |
| // Offset of the reserved TLSDESC_GOT entry when needed. |
| unsigned int tlsdesc_got_offset_; |
| // List of available regions within the section, for incremental |
| // update links. |
| Free_list free_list_; |
| }; |
| |
| template<int size> |
| class Output_data_plt_x86_64_standard : public Output_data_plt_x86_64<size> |
| { |
| public: |
| Output_data_plt_x86_64_standard(Layout* layout, |
| Output_data_got<64, false>* got, |
| Output_data_got_plt_x86_64* got_plt, |
| Output_data_space* got_irelative) |
| : Output_data_plt_x86_64<size>(layout, plt_entry_size, |
| got, got_plt, got_irelative) |
| { } |
| |
| Output_data_plt_x86_64_standard(Layout* layout, |
| Output_data_got<64, false>* got, |
| Output_data_got_plt_x86_64* got_plt, |
| Output_data_space* got_irelative, |
| unsigned int plt_count) |
| : Output_data_plt_x86_64<size>(layout, plt_entry_size, |
| got, got_plt, got_irelative, |
| plt_count) |
| { } |
| |
| protected: |
| virtual unsigned int |
| do_get_plt_entry_size() const |
| { return plt_entry_size; } |
| |
| virtual void |
| do_add_eh_frame(Layout* layout) |
| { |
| layout->add_eh_frame_for_plt(this, |
| this->plt_eh_frame_cie, |
| this->plt_eh_frame_cie_size, |
| plt_eh_frame_fde, |
| plt_eh_frame_fde_size); |
| } |
| |
| virtual void |
| do_fill_first_plt_entry(unsigned char* pov, |
| typename elfcpp::Elf_types<size>::Elf_Addr got_addr, |
| typename elfcpp::Elf_types<size>::Elf_Addr plt_addr); |
| |
| virtual unsigned int |
| do_fill_plt_entry(unsigned char* pov, |
| typename elfcpp::Elf_types<size>::Elf_Addr got_address, |
| typename elfcpp::Elf_types<size>::Elf_Addr plt_address, |
| unsigned int got_offset, |
| unsigned int plt_offset, |
| unsigned int plt_index); |
| |
| virtual void |
| do_fill_tlsdesc_entry(unsigned char* pov, |
| typename elfcpp::Elf_types<size>::Elf_Addr got_address, |
| typename elfcpp::Elf_types<size>::Elf_Addr plt_address, |
| typename elfcpp::Elf_types<size>::Elf_Addr got_base, |
| unsigned int tlsdesc_got_offset, |
| unsigned int plt_offset); |
| |
| private: |
| // The size of an entry in the PLT. |
| static const int plt_entry_size = 16; |
| |
| // The first entry in the PLT. |
| // From the AMD64 ABI: "Unlike Intel386 ABI, this ABI uses the same |
| // procedure linkage table for both programs and shared objects." |
| static const unsigned char first_plt_entry[plt_entry_size]; |
| |
| // Other entries in the PLT for an executable. |
| static const unsigned char plt_entry[plt_entry_size]; |
| |
| // The reserved TLSDESC entry in the PLT for an executable. |
| static const unsigned char tlsdesc_plt_entry[plt_entry_size]; |
| |
| // The .eh_frame unwind information for the PLT. |
| static const int plt_eh_frame_fde_size = 32; |
| static const unsigned char plt_eh_frame_fde[plt_eh_frame_fde_size]; |
| }; |
| |
| // We use this PLT when Indirect Branch Tracking (IBT) is enabled. |
| |
| template <int size> |
| class Output_data_plt_x86_64_ibt : public Output_data_plt_x86_64<size> |
| { |
| public: |
| Output_data_plt_x86_64_ibt(Layout* layout, |
| Output_data_got<64, false>* got, |
| Output_data_got_plt_x86_64* got_plt, |
| Output_data_space* got_irelative) |
| : Output_data_plt_x86_64<size>(layout, plt_entry_size, |
| got, got_plt, got_irelative), |
| aplt_offset_(0) |
| { } |
| |
| Output_data_plt_x86_64_ibt(Layout* layout, |
| Output_data_got<64, false>* got, |
| Output_data_got_plt_x86_64* got_plt, |
| Output_data_space* got_irelative, |
| unsigned int plt_count) |
| : Output_data_plt_x86_64<size>(layout, plt_entry_size, |
| got, got_plt, got_irelative, |
| plt_count), |
| aplt_offset_(0) |
| { } |
| |
| protected: |
| virtual unsigned int |
| do_get_plt_entry_size() const |
| { return plt_entry_size; } |
| |
| // Return the PLT address to use for a global symbol. |
| uint64_t |
| do_address_for_global(const Symbol*); |
| |
| // Return the PLT address to use for a local symbol. |
| uint64_t |
| do_address_for_local(const Relobj*, unsigned int symndx); |
| |
| virtual void |
| do_add_eh_frame(Layout* layout) |
| { |
| layout->add_eh_frame_for_plt(this, |
| this->plt_eh_frame_cie, |
| this->plt_eh_frame_cie_size, |
| plt_eh_frame_fde, |
| plt_eh_frame_fde_size); |
| } |
| |
| virtual void |
| do_fill_first_plt_entry(unsigned char* pov, |
| typename elfcpp::Elf_types<size>::Elf_Addr got_addr, |
| typename elfcpp::Elf_types<size>::Elf_Addr plt_addr); |
| |
| virtual unsigned int |
| do_fill_plt_entry(unsigned char* pov, |
| typename elfcpp::Elf_types<size>::Elf_Addr got_address, |
| typename elfcpp::Elf_types<size>::Elf_Addr plt_address, |
| unsigned int got_offset, |
| unsigned int plt_offset, |
| unsigned int plt_index); |
| |
| virtual void |
| do_fill_tlsdesc_entry(unsigned char* pov, |
| typename elfcpp::Elf_types<size>::Elf_Addr got_address, |
| typename elfcpp::Elf_types<size>::Elf_Addr plt_address, |
| typename elfcpp::Elf_types<size>::Elf_Addr got_base, |
| unsigned int tlsdesc_got_offset, |
| unsigned int plt_offset); |
| |
| void |
| fill_aplt_entry(unsigned char* pov, |
| typename elfcpp::Elf_types<size>::Elf_Addr got_address, |
| typename elfcpp::Elf_types<size>::Elf_Addr plt_address, |
| unsigned int got_offset, |
| unsigned int plt_offset, |
| unsigned int plt_index); |
| |
| private: |
| // Set the final size. |
| void |
| set_final_data_size(); |
| |
| // Write out the PLT data. |
| void |
| do_write(Output_file*); |
| |
| // Offset of the Additional PLT (if using -z bndplt). |
| unsigned int aplt_offset_; |
| |
| // The size of an entry in the PLT. |
| static const int plt_entry_size = 16; |
| |
| // The size of an entry in the additional PLT. |
| static const int aplt_entry_size = 16; |
| |
| // The first entry in the PLT. |
| // From the AMD64 ABI: "Unlike Intel386 ABI, this ABI uses the same |
| // procedure linkage table for both programs and shared objects." |
| static const unsigned char first_plt_entry[plt_entry_size]; |
| |
| // Other entries in the PLT for an executable. |
| static const unsigned char plt_entry[plt_entry_size]; |
| |
| // Entries in the additional PLT. |
| static const unsigned char aplt_entry[aplt_entry_size]; |
| |
| // The reserved TLSDESC entry in the PLT for an executable. |
| static const unsigned char tlsdesc_plt_entry[plt_entry_size]; |
| |
| // The .eh_frame unwind information for the PLT. |
| static const int plt_eh_frame_fde_size = 32; |
| static const unsigned char plt_eh_frame_fde[plt_eh_frame_fde_size]; |
| }; |
| |
| template<int size> |
| class Lazy_view |
| { |
| public: |
| Lazy_view(Sized_relobj_file<size, false>* object, unsigned int data_shndx) |
| : object_(object), data_shndx_(data_shndx), view_(NULL), view_size_(0) |
| { } |
| |
| inline unsigned char |
| operator[](size_t offset) |
| { |
| if (this->view_ == NULL) |
| this->view_ = this->object_->section_contents(this->data_shndx_, |
| &this->view_size_, |
| true); |
| if (offset >= this->view_size_) |
| return 0; |
| return this->view_[offset]; |
| } |
| |
| private: |
| Sized_relobj_file<size, false>* object_; |
| unsigned int data_shndx_; |
| const unsigned char* view_; |
| section_size_type view_size_; |
| }; |
| |
| // The x86_64 target class. |
| // See the ABI at |
| // http://www.x86-64.org/documentation/abi.pdf |
| // TLS info comes from |
| // http://people.redhat.com/drepper/tls.pdf |
| // http://www.lsd.ic.unicamp.br/~oliva/writeups/TLS/RFC-TLSDESC-x86.txt |
| |
| template<int size> |
| class Target_x86_64 : public Sized_target<size, false> |
| { |
| public: |
| // In the x86_64 ABI (p 68), it says "The AMD64 ABI architectures |
| // uses only Elf64_Rela relocation entries with explicit addends." |
| typedef Output_data_reloc<elfcpp::SHT_RELA, true, size, false> Reloc_section; |
| |
| Target_x86_64(const Target::Target_info* info = &x86_64_info) |
| : Sized_target<size, false>(info), |
| got_(NULL), plt_(NULL), got_plt_(NULL), got_irelative_(NULL), |
| got_tlsdesc_(NULL), global_offset_table_(NULL), rela_dyn_(NULL), |
| rela_irelative_(NULL), copy_relocs_(elfcpp::R_X86_64_COPY), |
| got_mod_index_offset_(-1U), tlsdesc_reloc_info_(), |
| tls_base_symbol_defined_(false), isa_1_used_(0), isa_1_needed_(0), |
| feature_1_(0), feature_2_used_(0), feature_2_needed_(0), |
| object_isa_1_used_(0), object_feature_1_(0), |
| object_feature_2_used_(0), seen_first_object_(false) |
| { } |
| |
| // Hook for a new output section. |
| void |
| do_new_output_section(Output_section*) const; |
| |
| // Scan the relocations to look for symbol adjustments. |
| void |
| gc_process_relocs(Symbol_table* symtab, |
| Layout* layout, |
| Sized_relobj_file<size, false>* object, |
| unsigned int data_shndx, |
| unsigned int sh_type, |
| const unsigned char* prelocs, |
| size_t reloc_count, |
| Output_section* output_section, |
| bool needs_special_offset_handling, |
| size_t local_symbol_count, |
| const unsigned char* plocal_symbols); |
| |
| // Scan the relocations to look for symbol adjustments. |
| void |
| scan_relocs(Symbol_table* symtab, |
| Layout* layout, |
| Sized_relobj_file<size, false>* object, |
| unsigned int data_shndx, |
| unsigned int sh_type, |
| const unsigned char* prelocs, |
| size_t reloc_count, |
| Output_section* output_section, |
| bool needs_special_offset_handling, |
| size_t local_symbol_count, |
| const unsigned char* plocal_symbols); |
| |
| // Finalize the sections. |
| void |
| do_finalize_sections(Layout*, const Input_objects*, Symbol_table*); |
| |
| // Return the value to use for a dynamic which requires special |
| // treatment. |
| uint64_t |
| do_dynsym_value(const Symbol*) const; |
| |
| // Relocate a section. |
| void |
| relocate_section(const Relocate_info<size, false>*, |
| unsigned int sh_type, |
| const unsigned char* prelocs, |
| size_t reloc_count, |
| Output_section* output_section, |
| bool needs_special_offset_handling, |
| unsigned char* view, |
| typename elfcpp::Elf_types<size>::Elf_Addr view_address, |
| section_size_type view_size, |
| const Reloc_symbol_changes*); |
| |
| // Scan the relocs during a relocatable link. |
| void |
| scan_relocatable_relocs(Symbol_table* symtab, |
| Layout* layout, |
| Sized_relobj_file<size, false>* object, |
| unsigned int data_shndx, |
| unsigned int sh_type, |
| const unsigned char* prelocs, |
| size_t reloc_count, |
| Output_section* output_section, |
| bool needs_special_offset_handling, |
| size_t local_symbol_count, |
| const unsigned char* plocal_symbols, |
| Relocatable_relocs*); |
| |
| // Scan the relocs for --emit-relocs. |
| void |
| emit_relocs_scan(Symbol_table* symtab, |
| Layout* layout, |
| Sized_relobj_file<size, false>* object, |
| unsigned int data_shndx, |
| unsigned int sh_type, |
| const unsigned char* prelocs, |
| size_t reloc_count, |
| Output_section* output_section, |
| bool needs_special_offset_handling, |
| size_t local_symbol_count, |
| const unsigned char* plocal_syms, |
| Relocatable_relocs* rr); |
| |
| // Emit relocations for a section. |
| void |
| relocate_relocs( |
| const Relocate_info<size, false>*, |
| unsigned int sh_type, |
| const unsigned char* prelocs, |
| size_t reloc_count, |
| Output_section* output_section, |
| typename elfcpp::Elf_types<size>::Elf_Off offset_in_output_section, |
| unsigned char* view, |
| typename elfcpp::Elf_types<size>::Elf_Addr view_address, |
| section_size_type view_size, |
| unsigned char* reloc_view, |
| section_size_type reloc_view_size); |
| |
| // Return a string used to fill a code section with nops. |
| std::string |
| do_code_fill(section_size_type length) const; |
| |
| // Return whether SYM is defined by the ABI. |
| bool |
| do_is_defined_by_abi(const Symbol* sym) const |
| { return strcmp(sym->name(), "__tls_get_addr") == 0; } |
| |
| // Return the symbol index to use for a target specific relocation. |
| // The only target specific relocation is R_X86_64_TLSDESC for a |
| // local symbol, which is an absolute reloc. |
| unsigned int |
| do_reloc_symbol_index(void*, unsigned int r_type) const |
| { |
| gold_assert(r_type == elfcpp::R_X86_64_TLSDESC); |
| return 0; |
| } |
| |
| // Return the addend to use for a target specific relocation. |
| uint64_t |
| do_reloc_addend(void* arg, unsigned int r_type, uint64_t addend) const; |
| |
| // Return the PLT section. |
| uint64_t |
| do_plt_address_for_global(const Symbol* gsym) const |
| { return this->plt_section()->address_for_global(gsym); } |
| |
| uint64_t |
| do_plt_address_for_local(const Relobj* relobj, unsigned int symndx) const |
| { return this->plt_section()->address_for_local(relobj, symndx); } |
| |
| // This function should be defined in targets that can use relocation |
| // types to determine (implemented in local_reloc_may_be_function_pointer |
| // and global_reloc_may_be_function_pointer) |
| // if a function's pointer is taken. ICF uses this in safe mode to only |
| // fold those functions whose pointer is defintely not taken. For x86_64 |
| // pie binaries, safe ICF cannot be done by looking at only relocation |
| // types, and for certain cases (e.g. R_X86_64_PC32), the instruction |
| // opcode is checked as well to distinguish a function call from taking |
| // a function's pointer. |
| bool |
| do_can_check_for_function_pointers() const |
| { return true; } |
| |
| // Return the base for a DW_EH_PE_datarel encoding. |
| uint64_t |
| do_ehframe_datarel_base() const; |
| |
| // Adjust -fsplit-stack code which calls non-split-stack code. |
| void |
| do_calls_non_split(Relobj* object, unsigned int shndx, |
| section_offset_type fnoffset, section_size_type fnsize, |
| const unsigned char* prelocs, size_t reloc_count, |
| unsigned char* view, section_size_type view_size, |
| std::string* from, std::string* to) const; |
| |
| // Return the size of the GOT section. |
| section_size_type |
| got_size() const |
| { |
| gold_assert(this->got_ != NULL); |
| return this->got_->data_size(); |
| } |
| |
| // Return the number of entries in the GOT. |
| unsigned int |
| got_entry_count() const |
| { |
| if (this->got_ == NULL) |
| return 0; |
| return this->got_size() / 8; |
| } |
| |
| // Return the number of entries in the PLT. |
| unsigned int |
| plt_entry_count() const; |
| |
| // Return the offset of the first non-reserved PLT entry. |
| unsigned int |
| first_plt_entry_offset() const; |
| |
| // Return the size of each PLT entry. |
| unsigned int |
| plt_entry_size() const; |
| |
| // Return the size of each GOT entry. |
| unsigned int |
| got_entry_size() const |
| { return 8; }; |
| |
| // Create the GOT section for an incremental update. |
| Output_data_got_base* |
| init_got_plt_for_update(Symbol_table* symtab, |
| Layout* layout, |
| unsigned int got_count, |
| unsigned int plt_count); |
| |
| // Reserve a GOT entry for a local symbol, and regenerate any |
| // necessary dynamic relocations. |
| void |
| reserve_local_got_entry(unsigned int got_index, |
| Sized_relobj<size, false>* obj, |
| unsigned int r_sym, |
| unsigned int got_type); |
| |
| // Reserve a GOT entry for a global symbol, and regenerate any |
| // necessary dynamic relocations. |
| void |
| reserve_global_got_entry(unsigned int got_index, Symbol* gsym, |
| unsigned int got_type); |
| |
| // Register an existing PLT entry for a global symbol. |
| void |
| register_global_plt_entry(Symbol_table*, Layout*, unsigned int plt_index, |
| Symbol* gsym); |
| |
| // Force a COPY relocation for a given symbol. |
| void |
| emit_copy_reloc(Symbol_table*, Symbol*, Output_section*, off_t); |
| |
| // Apply an incremental relocation. |
| void |
| apply_relocation(const Relocate_info<size, false>* relinfo, |
| typename elfcpp::Elf_types<size>::Elf_Addr r_offset, |
| unsigned int r_type, |
| typename elfcpp::Elf_types<size>::Elf_Swxword r_addend, |
| const Symbol* gsym, |
| unsigned char* view, |
| typename elfcpp::Elf_types<size>::Elf_Addr address, |
| section_size_type view_size); |
| |
| // Add a new reloc argument, returning the index in the vector. |
| size_t |
| add_tlsdesc_info(Sized_relobj_file<size, false>* object, unsigned int r_sym) |
| { |
| this->tlsdesc_reloc_info_.push_back(Tlsdesc_info(object, r_sym)); |
| return this->tlsdesc_reloc_info_.size() - 1; |
| } |
| |
| Output_data_plt_x86_64<size>* |
| make_data_plt(Layout* layout, |
| Output_data_got<64, false>* got, |
| Output_data_got_plt_x86_64* got_plt, |
| Output_data_space* got_irelative) |
| { |
| return this->do_make_data_plt(layout, got, got_plt, got_irelative); |
| } |
| |
| Output_data_plt_x86_64<size>* |
| make_data_plt(Layout* layout, |
| Output_data_got<64, false>* got, |
| Output_data_got_plt_x86_64* got_plt, |
| Output_data_space* got_irelative, |
| unsigned int plt_count) |
| { |
| return this->do_make_data_plt(layout, got, got_plt, got_irelative, |
| plt_count); |
| } |
| |
| virtual Output_data_plt_x86_64<size>* |
| do_make_data_plt(Layout* layout, |
| Output_data_got<64, false>* got, |
| Output_data_got_plt_x86_64* got_plt, |
| Output_data_space* got_irelative); |
| |
| virtual Output_data_plt_x86_64<size>* |
| do_make_data_plt(Layout* layout, |
| Output_data_got<64, false>* got, |
| Output_data_got_plt_x86_64* got_plt, |
| Output_data_space* got_irelative, |
| unsigned int plt_count); |
| |
| private: |
| // The class which scans relocations. |
| class Scan |
| { |
| public: |
| Scan() |
| : issued_non_pic_error_(false) |
| { } |
| |
| static inline int |
| get_reference_flags(unsigned int r_type); |
| |
| inline void |
| local(Symbol_table* symtab, Layout* layout, Target_x86_64* target, |
| Sized_relobj_file<size, false>* object, |
| unsigned int data_shndx, |
| Output_section* output_section, |
| const elfcpp::Rela<size, false>& reloc, unsigned int r_type, |
| const elfcpp::Sym<size, false>& lsym, |
| bool is_discarded); |
| |
| inline void |
| global(Symbol_table* symtab, Layout* layout, Target_x86_64* target, |
| Sized_relobj_file<size, false>* object, |
| unsigned int data_shndx, |
| Output_section* output_section, |
| const elfcpp::Rela<size, false>& reloc, unsigned int r_type, |
| Symbol* gsym); |
| |
| inline bool |
| local_reloc_may_be_function_pointer(Symbol_table* symtab, Layout* layout, |
| Target_x86_64* target, |
| Sized_relobj_file<size, false>* object, |
| unsigned int data_shndx, |
| Output_section* output_section, |
| const elfcpp::Rela<size, false>& reloc, |
| unsigned int r_type, |
| const elfcpp::Sym<size, false>& lsym); |
| |
| inline bool |
| global_reloc_may_be_function_pointer(Symbol_table* symtab, Layout* layout, |
| Target_x86_64* target, |
| Sized_relobj_file<size, false>* object, |
| unsigned int data_shndx, |
| Output_section* output_section, |
| const elfcpp::Rela<size, false>& reloc, |
| unsigned int r_type, |
| Symbol* gsym); |
| |
| private: |
| static void |
| unsupported_reloc_local(Sized_relobj_file<size, false>*, |
| unsigned int r_type); |
| |
| static void |
| unsupported_reloc_global(Sized_relobj_file<size, false>*, |
| unsigned int r_type, Symbol*); |
| |
| void |
| check_non_pic(Relobj*, unsigned int r_type, Symbol*); |
| |
| inline bool |
| possible_function_pointer_reloc(Sized_relobj_file<size, false>* src_obj, |
| unsigned int src_indx, |
| unsigned int r_offset, |
| unsigned int r_type); |
| |
| bool |
| reloc_needs_plt_for_ifunc(Sized_relobj_file<size, false>*, |
| unsigned int r_type); |
| |
| // Whether we have issued an error about a non-PIC compilation. |
| bool issued_non_pic_error_; |
| }; |
| |
| // The class which implements relocation. |
| class Relocate |
| { |
| public: |
| Relocate() |
| : skip_call_tls_get_addr_(false) |
| { } |
| |
| ~Relocate() |
| { |
| if (this->skip_call_tls_get_addr_) |
| { |
| // FIXME: This needs to specify the location somehow. |
| gold_error(_("missing expected TLS relocation")); |
| } |
| } |
| |
| // Do a relocation. Return false if the caller should not issue |
| // any warnings about this relocation. |
| inline bool |
| relocate(const Relocate_info<size, false>*, unsigned int, |
| Target_x86_64*, Output_section*, size_t, const unsigned char*, |
| const Sized_symbol<size>*, const Symbol_value<size>*, |
| unsigned char*, typename elfcpp::Elf_types<size>::Elf_Addr, |
| section_size_type); |
| |
| private: |
| // Do a TLS relocation. |
| inline void |
| relocate_tls(const Relocate_info<size, false>*, Target_x86_64*, |
| size_t relnum, const elfcpp::Rela<size, false>&, |
| unsigned int r_type, const Sized_symbol<size>*, |
| const Symbol_value<size>*, |
| unsigned char*, typename elfcpp::Elf_types<size>::Elf_Addr, |
| section_size_type); |
| |
| // Do a TLS General-Dynamic to Initial-Exec transition. |
| inline void |
| tls_gd_to_ie(const Relocate_info<size, false>*, size_t relnum, |
| const elfcpp::Rela<size, false>&, unsigned int r_type, |
| typename elfcpp::Elf_types<size>::Elf_Addr value, |
| unsigned char* view, |
| typename elfcpp::Elf_types<size>::Elf_Addr, |
| section_size_type view_size); |
| |
| // Do a TLS General-Dynamic to Local-Exec transition. |
| inline void |
| tls_gd_to_le(const Relocate_info<size, false>*, size_t relnum, |
| Output_segment* tls_segment, |
| const elfcpp::Rela<size, false>&, unsigned int r_type, |
| typename elfcpp::Elf_types<size>::Elf_Addr value, |
| unsigned char* view, |
| section_size_type view_size); |
| |
| // Do a TLSDESC-style General-Dynamic to Initial-Exec transition. |
| inline void |
| tls_desc_gd_to_ie(const Relocate_info<size, false>*, size_t relnum, |
| const elfcpp::Rela<size, false>&, unsigned int r_type, |
| typename elfcpp::Elf_types<size>::Elf_Addr value, |
| unsigned char* view, |
| typename elfcpp::Elf_types<size>::Elf_Addr, |
| section_size_type view_size); |
| |
| // Do a TLSDESC-style General-Dynamic to Local-Exec transition. |
| inline void |
| tls_desc_gd_to_le(const Relocate_info<size, false>*, size_t relnum, |
| Output_segment* tls_segment, |
| const elfcpp::Rela<size, false>&, unsigned int r_type, |
| typename elfcpp::Elf_types<size>::Elf_Addr value, |
| unsigned char* view, |
| section_size_type view_size); |
| |
| // Do a TLS Local-Dynamic to Local-Exec transition. |
| inline void |
| tls_ld_to_le(const Relocate_info<size, false>*, size_t relnum, |
| Output_segment* tls_segment, |
| const elfcpp::Rela<size, false>&, unsigned int r_type, |
| typename elfcpp::Elf_types<size>::Elf_Addr value, |
| unsigned char* view, |
| section_size_type view_size); |
| |
| // Do a TLS Initial-Exec to Local-Exec transition. |
| static inline void |
| tls_ie_to_le(const Relocate_info<size, false>*, size_t relnum, |
| Output_segment* tls_segment, |
| const elfcpp::Rela<size, false>&, unsigned int r_type, |
| typename elfcpp::Elf_types<size>::Elf_Addr value, |
| unsigned char* view, |
| section_size_type view_size); |
| |
| // This is set if we should skip the next reloc, which should be a |
| // PLT32 reloc against ___tls_get_addr. |
| bool skip_call_tls_get_addr_; |
| }; |
| |
| // Check if relocation against this symbol is a candidate for |
| // conversion from |
| // mov foo@GOTPCREL(%rip), %reg |
| // to lea foo(%rip), %reg. |
| template<class View_type> |
| static inline bool |
| can_convert_mov_to_lea(const Symbol* gsym, unsigned int r_type, |
| size_t r_offset, View_type* view) |
| { |
| gold_assert(gsym != NULL); |
| // We cannot do the conversion unless it's one of these relocations. |
| if (r_type != elfcpp::R_X86_64_GOTPCREL |
| && r_type != elfcpp::R_X86_64_GOTPCRELX |
| && r_type != elfcpp::R_X86_64_REX_GOTPCRELX |
| && r_type != elfcpp::R_X86_64_CODE_4_GOTPCRELX) |
| return false; |
| // We cannot convert references to IFUNC symbols, or to symbols that |
| // are not local to the current module. |
| // We can't do predefined symbols because they may become undefined |
| // (e.g., __ehdr_start when the headers aren't mapped to a segment). |
| if (gsym->type() == elfcpp::STT_GNU_IFUNC |
| || gsym->is_undefined() |
| || gsym->is_predefined() |
| || gsym->is_from_dynobj() |
| || gsym->is_preemptible()) |
| return false; |
| // If we are building a shared object and the symbol is protected, we may |
| // need to go through the GOT. |
| if (parameters->options().shared() |
| && gsym->visibility() == elfcpp::STV_PROTECTED) |
| return false; |
| // We cannot convert references to the _DYNAMIC symbol. |
| if (strcmp(gsym->name(), "_DYNAMIC") == 0) |
| return false; |
| // Check for a MOV opcode. |
| return (*view)[r_offset - 2] == 0x8b; |
| } |
| |
| // Convert |
| // callq *foo@GOTPCRELX(%rip) to |
| // addr32 callq foo |
| // and jmpq *foo@GOTPCRELX(%rip) to |
| // jmpq foo |
| // nop |
| template<class View_type> |
| static inline bool |
| can_convert_callq_to_direct(const Symbol* gsym, unsigned int r_type, |
| size_t r_offset, View_type* view) |
| { |
| gold_assert(gsym != NULL); |
| // We cannot do the conversion unless it's a GOTPCRELX relocation. |
| if (r_type != elfcpp::R_X86_64_GOTPCRELX) |
| return false; |
| // We cannot convert references to IFUNC symbols, or to symbols that |
| // are not local to the current module. |
| if (gsym->type() == elfcpp::STT_GNU_IFUNC |
| || gsym->is_undefined () |
| || gsym->is_from_dynobj() |
| || gsym->is_preemptible()) |
| return false; |
| // Check for a CALLQ or JMPQ opcode. |
| return ((*view)[r_offset - 2] == 0xff |
| && ((*view)[r_offset - 1] == 0x15 |
| || (*view)[r_offset - 1] == 0x25)); |
| } |
| |
| // Adjust TLS relocation type based on the options and whether this |
| // is a local symbol. |
| static tls::Tls_optimization |
| optimize_tls_reloc(bool is_final, int r_type, size_t r_offset, |
| const unsigned char* reloc_view); |
| |
| // Get the GOT section, creating it if necessary. |
| Output_data_got<64, false>* |
| got_section(Symbol_table*, Layout*); |
| |
| // Get the GOT PLT section. |
| Output_data_got_plt_x86_64* |
| got_plt_section() const |
| { |
| gold_assert(this->got_plt_ != NULL); |
| return this->got_plt_; |
| } |
| |
| // Get the GOT section for TLSDESC entries. |
| Output_data_got<64, false>* |
| got_tlsdesc_section() const |
| { |
| gold_assert(this->got_tlsdesc_ != NULL); |
| return this->got_tlsdesc_; |
| } |
| |
| // Create the PLT section. |
| void |
| make_plt_section(Symbol_table* symtab, Layout* layout); |
| |
| // Create a PLT entry for a global symbol. |
| void |
| make_plt_entry(Symbol_table*, Layout*, Symbol*); |
| |
| // Create a PLT entry for a local STT_GNU_IFUNC symbol. |
| void |
| make_local_ifunc_plt_entry(Symbol_table*, Layout*, |
| Sized_relobj_file<size, false>* relobj, |
| unsigned int local_sym_index); |
| |
| // Define the _TLS_MODULE_BASE_ symbol in the TLS segment. |
| void |
| define_tls_base_symbol(Symbol_table*, Layout*); |
| |
| // Create the reserved PLT and GOT entries for the TLS descriptor resolver. |
| void |
| reserve_tlsdesc_entries(Symbol_table* symtab, Layout* layout); |
| |
| // Create a GOT entry for the TLS module index. |
| unsigned int |
| got_mod_index_entry(Symbol_table* symtab, Layout* layout, |
| Sized_relobj_file<size, false>* object); |
| |
| // Get the PLT section. |
| Output_data_plt_x86_64<size>* |
| plt_section() const |
| { |
| gold_assert(this->plt_ != NULL); |
| return this->plt_; |
| } |
| |
| // Get the dynamic reloc section, creating it if necessary. |
| Reloc_section* |
| rela_dyn_section(Layout*); |
| |
| // Get the section to use for TLSDESC relocations. |
| Reloc_section* |
| rela_tlsdesc_section(Layout*) const; |
| |
| // Get the section to use for IRELATIVE relocations. |
| Reloc_section* |
| rela_irelative_section(Layout*); |
| |
| // Add a potential copy relocation. |
| void |
| copy_reloc(Symbol_table* symtab, Layout* layout, |
| Sized_relobj_file<size, false>* object, |
| unsigned int shndx, Output_section* output_section, |
| Symbol* sym, const elfcpp::Rela<size, false>& reloc) |
| { |
| unsigned int r_type = elfcpp::elf_r_type<size>(reloc.get_r_info()); |
| this->copy_relocs_.copy_reloc(symtab, layout, |
| symtab->get_sized_symbol<size>(sym), |
| object, shndx, output_section, |
| r_type, reloc.get_r_offset(), |
| reloc.get_r_addend(), |
| this->rela_dyn_section(layout)); |
| } |
| |
| // Record a target-specific program property in the .note.gnu.property |
| // section. |
| void |
| record_gnu_property(unsigned int, unsigned int, size_t, |
| const unsigned char*, const Object*); |
| |
| // Merge the target-specific program properties from the current object. |
| void |
| merge_gnu_properties(const Object*); |
| |
| // Finalize the target-specific program properties and add them back to |
| // the layout. |
| void |
| do_finalize_gnu_properties(Layout*) const; |
| |
| // Information about this specific target which we pass to the |
| // general Target structure. |
| static const Target::Target_info x86_64_info; |
| |
| // The types of GOT entries needed for this platform. |
| // These values are exposed to the ABI in an incremental link. |
| // Do not renumber existing values without changing the version |
| // number of the .gnu_incremental_inputs section. |
| enum Got_type |
| { |
| GOT_TYPE_STANDARD = 0, // GOT entry for a regular symbol |
| GOT_TYPE_TLS_OFFSET = 1, // GOT entry for TLS offset |
| GOT_TYPE_TLS_PAIR = 2, // GOT entry for TLS module/offset pair |
| GOT_TYPE_TLS_DESC = 3 // GOT entry for TLS_DESC pair |
| }; |
| |
| // This type is used as the argument to the target specific |
| // relocation routines. The only target specific reloc is |
| // R_X86_64_TLSDESC against a local symbol. |
| struct Tlsdesc_info |
| { |
| Tlsdesc_info(Sized_relobj_file<size, false>* a_object, unsigned int a_r_sym) |
| : object(a_object), r_sym(a_r_sym) |
| { } |
| |
| // The object in which the local symbol is defined. |
| Sized_relobj_file<size, false>* object; |
| // The local symbol index in the object. |
| unsigned int r_sym; |
| }; |
| |
| // The GOT section. |
| Output_data_got<64, false>* got_; |
| // The PLT section. |
| Output_data_plt_x86_64<size>* plt_; |
| // The GOT PLT section. |
| Output_data_got_plt_x86_64* got_plt_; |
| // The GOT section for IRELATIVE relocations. |
| Output_data_space* got_irelative_; |
| // The GOT section for TLSDESC relocations. |
| Output_data_got<64, false>* got_tlsdesc_; |
| // The _GLOBAL_OFFSET_TABLE_ symbol. |
| Symbol* global_offset_table_; |
| // The dynamic reloc section. |
| Reloc_section* rela_dyn_; |
| // The section to use for IRELATIVE relocs. |
| Reloc_section* rela_irelative_; |
| // Relocs saved to avoid a COPY reloc. |
| Copy_relocs<elfcpp::SHT_RELA, size, false> copy_relocs_; |
| // Offset of the GOT entry for the TLS module index. |
| unsigned int got_mod_index_offset_; |
| // We handle R_X86_64_TLSDESC against a local symbol as a target |
| // specific relocation. Here we store the object and local symbol |
| // index for the relocation. |
| std::vector<Tlsdesc_info> tlsdesc_reloc_info_; |
| // True if the _TLS_MODULE_BASE_ symbol has been defined. |
| bool tls_base_symbol_defined_; |
| // Target-specific program properties, from .note.gnu.property section. |
| // Each bit represents a specific feature. |
| uint32_t isa_1_used_; |
| uint32_t isa_1_needed_; |
| uint32_t feature_1_; |
| uint32_t feature_2_used_; |
| uint32_t feature_2_needed_; |
| // Target-specific properties from the current object. |
| // These bits get ORed into ISA_1_USED_ after all properties for the object |
| // have been processed. But if either is all zeroes (as when the property |
| // is absent from an object), the result should be all zeroes. |
| // (See PR ld/23486.) |
| uint32_t object_isa_1_used_; |
| // These bits get ANDed into FEATURE_1_ after all properties for the object |
| // have been processed. |
| uint32_t object_feature_1_; |
| uint32_t object_feature_2_used_; |
| // Whether we have seen our first object, for use in initializing FEATURE_1_. |
| bool seen_first_object_; |
| }; |
| |
| template<> |
| const Target::Target_info Target_x86_64<64>::x86_64_info = |
| { |
| 64, // size |
| false, // is_big_endian |
| elfcpp::EM_X86_64, // machine_code |
| false, // has_make_symbol |
| false, // has_resolve |
| true, // has_code_fill |
| true, // is_default_stack_executable |
| true, // can_icf_inline_merge_sections |
| '\0', // wrap_char |
| "/lib/ld64.so.1", // program interpreter |
| 0x400000, // default_text_segment_address |
| 0x1000, // abi_pagesize (overridable by -z max-page-size) |
| 0x1000, // common_pagesize (overridable by -z common-page-size) |
| false, // isolate_execinstr |
| 0, // rosegment_gap |
| elfcpp::SHN_UNDEF, // small_common_shndx |
| elfcpp::SHN_X86_64_LCOMMON, // large_common_shndx |
| 0, // small_common_section_flags |
| elfcpp::SHF_X86_64_LARGE, // large_common_section_flags |
| NULL, // attributes_section |
| NULL, // attributes_vendor |
| "_start", // entry_symbol_name |
| 32, // hash_entry_size |
| elfcpp::SHT_X86_64_UNWIND, // unwind_section_type |
| }; |
| |
| template<> |
| const Target::Target_info Target_x86_64<32>::x86_64_info = |
| { |
| 32, // size |
| false, // is_big_endian |
| elfcpp::EM_X86_64, // machine_code |
| false, // has_make_symbol |
| false, // has_resolve |
| true, // has_code_fill |
| true, // is_default_stack_executable |
| true, // can_icf_inline_merge_sections |
| '\0', // wrap_char |
| "/libx32/ldx32.so.1", // program interpreter |
| 0x400000, // default_text_segment_address |
| 0x1000, // abi_pagesize (overridable by -z max-page-size) |
| 0x1000, // common_pagesize (overridable by -z common-page-size) |
| false, // isolate_execinstr |
| 0, // rosegment_gap |
| elfcpp::SHN_UNDEF, // small_common_shndx |
| elfcpp::SHN_X86_64_LCOMMON, // large_common_shndx |
| 0, // small_common_section_flags |
| elfcpp::SHF_X86_64_LARGE, // large_common_section_flags |
| NULL, // attributes_section |
| NULL, // attributes_vendor |
| "_start", // entry_symbol_name |
| 32, // hash_entry_size |
| elfcpp::SHT_X86_64_UNWIND, // unwind_section_type |
| }; |
| |
| // This is called when a new output section is created. This is where |
| // we handle the SHF_X86_64_LARGE. |
| |
| template<int size> |
| void |
| Target_x86_64<size>::do_new_output_section(Output_section* os) const |
| { |
| if ((os->flags() & elfcpp::SHF_X86_64_LARGE) != 0) |
| os->set_is_large_section(); |
| } |
| |
| // Get the GOT section, creating it if necessary. |
| |
| template<int size> |
| Output_data_got<64, false>* |
| Target_x86_64<size>::got_section(Symbol_table* symtab, Layout* layout) |
| { |
| if (this->got_ == NULL) |
| { |
| gold_assert(symtab != NULL && layout != NULL); |
| |
| // When using -z now, we can treat .got.plt as a relro section. |
| // Without -z now, it is modified after program startup by lazy |
| // PLT relocations. |
| bool is_got_plt_relro = parameters->options().now(); |
| Output_section_order got_order = (is_got_plt_relro |
| ? ORDER_RELRO |
| : ORDER_RELRO_LAST); |
| Output_section_order got_plt_order = (is_got_plt_relro |
| ? ORDER_RELRO |
| : ORDER_NON_RELRO_FIRST); |
| |
| this->got_ = new Output_data_got<64, false>(); |
| |
| layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS, |
| (elfcpp::SHF_ALLOC |
| | elfcpp::SHF_WRITE), |
| this->got_, got_order, true); |
| |
| this->got_plt_ = new Output_data_got_plt_x86_64(layout); |
| layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS, |
| (elfcpp::SHF_ALLOC |
| | elfcpp::SHF_WRITE), |
| this->got_plt_, got_plt_order, |
| is_got_plt_relro); |
| |
| // The first three entries are reserved. |
| this->got_plt_->set_current_data_size(3 * 8); |
| |
| if (!is_got_plt_relro) |
| { |
| // Those bytes can go into the relro segment. |
| layout->increase_relro(3 * 8); |
| } |
| |
| // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT. |
| this->global_offset_table_ = |
| symtab->define_in_output_data("_GLOBAL_OFFSET_TABLE_", NULL, |
| Symbol_table::PREDEFINED, |
| this->got_plt_, |
| 0, 0, elfcpp::STT_OBJECT, |
| elfcpp::STB_LOCAL, |
| elfcpp::STV_HIDDEN, 0, |
| false, false); |
| |
| // If there are any IRELATIVE relocations, they get GOT entries |
| // in .got.plt after the jump slot entries. |
| this->got_irelative_ = new Output_data_space(8, "** GOT IRELATIVE PLT"); |
| layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS, |
| (elfcpp::SHF_ALLOC |
| | elfcpp::SHF_WRITE), |
| this->got_irelative_, |
| got_plt_order, is_got_plt_relro); |
| |
| // If there are any TLSDESC relocations, they get GOT entries in |
| // .got.plt after the jump slot and IRELATIVE entries. |
| this->got_tlsdesc_ = new Output_data_got<64, false>(); |
| layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS, |
| (elfcpp::SHF_ALLOC |
| | elfcpp::SHF_WRITE), |
| this->got_tlsdesc_, |
| got_plt_order, is_got_plt_relro); |
| } |
| |
| return this->got_; |
| } |
| |
| // Get the dynamic reloc section, creating it if necessary. |
| |
| template<int size> |
| typename Target_x86_64<size>::Reloc_section* |
| Target_x86_64<size>::rela_dyn_section(Layout* layout) |
| { |
| if (this->rela_dyn_ == NULL) |
| { |
| gold_assert(layout != NULL); |
| this->rela_dyn_ = new Reloc_section(parameters->options().combreloc()); |
| layout->add_output_section_data(".rela.dyn", elfcpp::SHT_RELA, |
| elfcpp::SHF_ALLOC, this->rela_dyn_, |
| ORDER_DYNAMIC_RELOCS, false); |
| } |
| return this->rela_dyn_; |
| } |
| |
| // Get the section to use for IRELATIVE relocs, creating it if |
| // necessary. These go in .rela.dyn, but only after all other dynamic |
| // relocations. They need to follow the other dynamic relocations so |
| // that they can refer to global variables initialized by those |
| // relocs. |
| |
| template<int size> |
| typename Target_x86_64<size>::Reloc_section* |
| Target_x86_64<size>::rela_irelative_section(Layout* layout) |
| { |
| if (this->rela_irelative_ == NULL) |
| { |
| // Make sure we have already created the dynamic reloc section. |
| this->rela_dyn_section(layout); |
| this->rela_irelative_ = new Reloc_section(false); |
| layout->add_output_section_data(".rela.dyn", elfcpp::SHT_RELA, |
| elfcpp::SHF_ALLOC, this->rela_irelative_, |
| ORDER_DYNAMIC_RELOCS, false); |
| gold_assert(this->rela_dyn_->output_section() |
| == this->rela_irelative_->output_section()); |
| } |
| return this->rela_irelative_; |
| } |
| |
| // Record a target-specific program property from the .note.gnu.property |
| // section. |
| template<int size> |
| void |
| Target_x86_64<size>::record_gnu_property( |
| unsigned int, unsigned int pr_type, |
| size_t pr_datasz, const unsigned char* pr_data, |
| const Object* object) |
| { |
| uint32_t val = 0; |
| |
| switch (pr_type) |
| { |
| case elfcpp::GNU_PROPERTY_X86_COMPAT_ISA_1_USED: |
| case elfcpp::GNU_PROPERTY_X86_COMPAT_ISA_1_NEEDED: |
| case elfcpp::GNU_PROPERTY_X86_COMPAT_2_ISA_1_USED: |
| case elfcpp::GNU_PROPERTY_X86_COMPAT_2_ISA_1_NEEDED: |
| case elfcpp::GNU_PROPERTY_X86_ISA_1_USED: |
| case elfcpp::GNU_PROPERTY_X86_ISA_1_NEEDED: |
| case elfcpp::GNU_PROPERTY_X86_FEATURE_1_AND: |
| case elfcpp::GNU_PROPERTY_X86_FEATURE_2_USED: |
| case elfcpp::GNU_PROPERTY_X86_FEATURE_2_NEEDED: |
| if (pr_datasz != 4) |
| { |
| gold_warning(_("%s: corrupt .note.gnu.property section " |
| "(pr_datasz for property %d is not 4)"), |
| object->name().c_str(), pr_type); |
| return; |
| } |
| val = elfcpp::Swap<32, false>::readval(pr_data); |
| break; |
| default: |
| gold_warning(_("%s: unknown program property type 0x%x " |
| "in .note.gnu.property section"), |
| object->name().c_str(), pr_type); |
| break; |
| } |
| |
| switch (pr_type) |
| { |
| case elfcpp::GNU_PROPERTY_X86_ISA_1_USED: |
| this->object_isa_1_used_ |= val; |
| break; |
| case elfcpp::GNU_PROPERTY_X86_ISA_1_NEEDED: |
| this->isa_1_needed_ |= val; |
| break; |
| case elfcpp::GNU_PROPERTY_X86_FEATURE_1_AND: |
| // If we see multiple feature props in one object, OR them together. |
| this->object_feature_1_ |= val; |
| break; |
| case elfcpp::GNU_PROPERTY_X86_FEATURE_2_USED: |
| this->object_feature_2_used_ |= val; |
| break; |
| case elfcpp::GNU_PROPERTY_X86_FEATURE_2_NEEDED: |
| this->feature_2_needed_ |= val; |
| break; |
| } |
| } |
| |
| // Merge the target-specific program properties from the current object. |
| template<int size> |
| void |
| Target_x86_64<size>::merge_gnu_properties(const Object*) |
| { |
| if (this->seen_first_object_) |
| { |
| // If any object is missing the ISA_1_USED property, we must omit |
| // it from the output file. |
| if (this->object_isa_1_used_ == 0) |
| this->isa_1_used_ = 0; |
| else if (this->isa_1_used_ != 0) |
| this->isa_1_used_ |= this->object_isa_1_used_; |
| this->feature_1_ &= this->object_feature_1_; |
| // If any object is missing the FEATURE_2_USED property, we must |
| // omit it from the output file. |
| if (this->object_feature_2_used_ == 0) |
| this->feature_2_used_ = 0; |
| else if (this->feature_2_used_ != 0) |
| this->feature_2_used_ |= this->object_feature_2_used_; |
| } |
| else |
| { |
| this->isa_1_used_ = this->object_isa_1_used_; |
| this->feature_1_ = this->object_feature_1_; |
| this->feature_2_used_ = this->object_feature_2_used_; |
| this->seen_first_object_ = true; |
| } |
| this->object_isa_1_used_ = 0; |
| this->object_feature_1_ = 0; |
| this->object_feature_2_used_ = 0; |
| } |
| |
| static inline void |
| add_property(Layout* layout, unsigned int pr_type, uint32_t val) |
| { |
| unsigned char buf[4]; |
| elfcpp::Swap<32, false>::writeval(buf, val); |
| layout->add_gnu_property(elfcpp::NT_GNU_PROPERTY_TYPE_0, pr_type, 4, buf); |
| } |
| |
| // Finalize the target-specific program properties and add them back to |
| // the layout. |
| template<int size> |
| void |
| Target_x86_64<size>::do_finalize_gnu_properties(Layout* layout) const |
| { |
| if (this->isa_1_used_ != 0) |
| add_property(layout, elfcpp::GNU_PROPERTY_X86_ISA_1_USED, |
| this->isa_1_used_); |
| if (this->isa_1_needed_ != 0) |
| add_property(layout, elfcpp::GNU_PROPERTY_X86_ISA_1_NEEDED, |
| this->isa_1_needed_); |
| if (this->feature_1_ != 0) |
| add_property(layout, elfcpp::GNU_PROPERTY_X86_FEATURE_1_AND, |
| this->feature_1_); |
| if (this->feature_2_used_ != 0) |
| add_property(layout, elfcpp::GNU_PROPERTY_X86_FEATURE_2_USED, |
| this->feature_2_used_); |
| if (this->feature_2_needed_ != 0) |
| add_property(layout, elfcpp::GNU_PROPERTY_X86_FEATURE_2_NEEDED, |
| this->feature_2_needed_); |
| } |
| |
| // Write the first three reserved words of the .got.plt section. |
| // The remainder of the section is written while writing the PLT |
| // in Output_data_plt_i386::do_write. |
| |
| void |
| Output_data_got_plt_x86_64::do_write(Output_file* of) |
| { |
| // The first entry in the GOT is the address of the .dynamic section |
| // aka the PT_DYNAMIC segment. The next two entries are reserved. |
| // We saved space for them when we created the section in |
| // Target_x86_64::got_section. |
| const off_t got_file_offset = this->offset(); |
| gold_assert(this->data_size() >= 24); |
| unsigned char* const got_view = of->get_output_view(got_file_offset, 24); |
| Output_section* dynamic = this->layout_->dynamic_section(); |
| uint64_t dynamic_addr = dynamic == NULL ? 0 : dynamic->address(); |
| elfcpp::Swap<64, false>::writeval(got_view, dynamic_addr); |
| memset(got_view + 8, 0, 16); |
| of->write_output_view(got_file_offset, 24, got_view); |
| } |
| |
| // Initialize the PLT section. |
| |
| template<int size> |
| void |
| Output_data_plt_x86_64<size>::init(Layout* layout) |
| { |
| this->rel_ = new Reloc_section(false); |
| layout->add_output_section_data(".rela.plt", elfcpp::SHT_RELA, |
| elfcpp::SHF_ALLOC, this->rel_, |
| ORDER_DYNAMIC_PLT_RELOCS, false); |
| } |
| |
| template<int size> |
| void |
| Output_data_plt_x86_64<size>::do_adjust_output_section(Output_section* os) |
| { |
| os->set_entsize(this->get_plt_entry_size()); |
| } |
| |
| // Add an entry to the PLT. |
| |
| template<int size> |
| void |
| Output_data_plt_x86_64<size>::add_entry(Symbol_table* symtab, Layout* layout, |
| Symbol* gsym) |
| { |
| gold_assert(!gsym->has_plt_offset()); |
| |
| unsigned int plt_index; |
| off_t plt_offset; |
| section_offset_type got_offset; |
| |
| unsigned int* pcount; |
| unsigned int offset; |
| unsigned int reserved; |
| Output_section_data_build* got; |
| if (gsym->type() == elfcpp::STT_GNU_IFUNC |
| && gsym->can_use_relative_reloc(false)) |
| { |
| pcount = &this->irelative_count_; |
| offset = 0; |
| reserved = 0; |
| got = this->got_irelative_; |
| } |
| else |
| { |
| pcount = &this->count_; |
| offset = 1; |
| reserved = 3; |
| got = this->got_plt_; |
| } |
| |
| if (!this->is_data_size_valid()) |
| { |
| // Note that when setting the PLT offset for a non-IRELATIVE |
| // entry we skip the initial reserved PLT entry. |
| plt_index = *pcount + offset; |
| plt_offset = plt_index * this->get_plt_entry_size(); |
| |
| ++*pcount; |
| |
| got_offset = (plt_index - offset + reserved) * 8; |
| gold_assert(got_offset == got->current_data_size()); |
| |
| // Every PLT entry needs a GOT entry which points back to the PLT |
| // entry (this will be changed by the dynamic linker, normally |
| // lazily when the function is called). |
| got->set_current_data_size(got_offset + 8); |
| } |
| else |
| { |
| // FIXME: This is probably not correct for IRELATIVE relocs. |
| |
| // For incremental updates, find an available slot. |
| plt_offset = this->free_list_.allocate(this->get_plt_entry_size(), |
| this->get_plt_entry_size(), 0); |
| if (plt_offset == -1) |
| gold_fallback(_("out of patch space (PLT);" |
| " relink with --incremental-full")); |
| |
| // The GOT and PLT entries have a 1-1 correspondance, so the GOT offset |
| // can be calculated from the PLT index, adjusting for the three |
| // reserved entries at the beginning of the GOT. |
| plt_index = plt_offset / this->get_plt_entry_size() - 1; |
| got_offset = (plt_index - offset + reserved) * 8; |
| } |
| |
| gsym->set_plt_offset(plt_offset); |
| |
| // Every PLT entry needs a reloc. |
| this->add_relocation(symtab, layout, gsym, got_offset); |
| |
| // Note that we don't need to save the symbol. The contents of the |
| // PLT are independent of which symbols are used. The symbols only |
| // appear in the relocations. |
| } |
| |
| // Add an entry to the PLT for a local STT_GNU_IFUNC symbol. Return |
| // the PLT offset. |
| |
| template<int size> |
| unsigned int |
| Output_data_plt_x86_64<size>::add_local_ifunc_entry( |
| Symbol_table* symtab, |
| Layout* layout, |
| Sized_relobj_file<size, false>* relobj, |
| unsigned int local_sym_index) |
| { |
| unsigned int plt_offset = this->irelative_count_ * this->get_plt_entry_size(); |
| ++this->irelative_count_; |
| |
| section_offset_type got_offset = this->got_irelative_->current_data_size(); |
| |
| // Every PLT entry needs a GOT entry which points back to the PLT |
| // entry. |
| this->got_irelative_->set_current_data_size(got_offset + 8); |
| |
| // Every PLT entry needs a reloc. |
| Reloc_section* rela = this->rela_irelative(symtab, layout); |
| rela->add_symbolless_local_addend(relobj, local_sym_index, |
| elfcpp::R_X86_64_IRELATIVE, |
| this->got_irelative_, got_offset, 0); |
| |
| return plt_offset; |
| } |
| |
| // Add the relocation for a PLT entry. |
| |
| template<int size> |
| void |
| Output_data_plt_x86_64<size>::add_relocation(Symbol_table* symtab, |
| Layout* layout, |
| Symbol* gsym, |
| unsigned int got_offset) |
| { |
| if (gsym->type() == elfcpp::STT_GNU_IFUNC |
| && gsym->can_use_relative_reloc(false)) |
| { |
| Reloc_section* rela = this->rela_irelative(symtab, layout); |
| rela->add_symbolless_global_addend(gsym, elfcpp::R_X86_64_IRELATIVE, |
| this->got_irelative_, got_offset, 0); |
| } |
| else |
| { |
| gsym->set_needs_dynsym_entry(); |
| this->rel_->add_global(gsym, elfcpp::R_X86_64_JUMP_SLOT, this->got_plt_, |
| got_offset, 0); |
| } |
| } |
| |
| // Return where the TLSDESC relocations should go, creating it if |
| // necessary. These follow the JUMP_SLOT relocations. |
| |
| template<int size> |
| typename Output_data_plt_x86_64<size>::Reloc_section* |
| Output_data_plt_x86_64<size>::rela_tlsdesc(Layout* layout) |
| { |
| if (this->tlsdesc_rel_ == NULL) |
| { |
| this->tlsdesc_rel_ = new Reloc_section(false); |
| layout->add_output_section_data(".rela.plt", elfcpp::SHT_RELA, |
| elfcpp::SHF_ALLOC, this->tlsdesc_rel_, |
| ORDER_DYNAMIC_PLT_RELOCS, false); |
| gold_assert(this->tlsdesc_rel_->output_section() |
| == this->rel_->output_section()); |
| } |
| return this->tlsdesc_rel_; |
| } |
| |
| // Return where the IRELATIVE relocations should go in the PLT. These |
| // follow the JUMP_SLOT and the TLSDESC relocations. |
| |
| template<int size> |
| typename Output_data_plt_x86_64<size>::Reloc_section* |
| Output_data_plt_x86_64<size>::rela_irelative(Symbol_table* symtab, |
| Layout* layout) |
| { |
| if (this->irelative_rel_ == NULL) |
| { |
| // Make sure we have a place for the TLSDESC relocations, in |
| // case we see any later on. |
| this->rela_tlsdesc(layout); |
| this->irelative_rel_ = new Reloc_section(false); |
| layout->add_output_section_data(".rela.plt", elfcpp::SHT_RELA, |
| elfcpp::SHF_ALLOC, this->irelative_rel_, |
| ORDER_DYNAMIC_PLT_RELOCS, false); |
| gold_assert(this->irelative_rel_->output_section() |
| == this->rel_->output_section()); |
| |
| if (parameters->doing_static_link()) |
| { |
| // A statically linked executable will only have a .rela.plt |
| // section to hold R_X86_64_IRELATIVE relocs for |
| // STT_GNU_IFUNC symbols. The library will use these |
| // symbols to locate the IRELATIVE relocs at program startup |
| // time. |
| symtab->define_in_output_data("__rela_iplt_start", NULL, |
| Symbol_table::PREDEFINED, |
| this->irelative_rel_, 0, 0, |
| elfcpp::STT_NOTYPE, elfcpp::STB_GLOBAL, |
| elfcpp::STV_HIDDEN, 0, false, true); |
| symtab->define_in_output_data("__rela_iplt_end", NULL, |
| Symbol_table::PREDEFINED, |
| this->irelative_rel_, 0, 0, |
| elfcpp::STT_NOTYPE, elfcpp::STB_GLOBAL, |
| elfcpp::STV_HIDDEN, 0, true, true); |
| } |
| } |
| return this->irelative_rel_; |
| } |
| |
| // Return the PLT address to use for a global symbol. |
| |
| template<int size> |
| uint64_t |
| Output_data_plt_x86_64<size>::do_address_for_global(const Symbol* gsym) |
| { |
| uint64_t offset = 0; |
| if (gsym->type() == elfcpp::STT_GNU_IFUNC |
| && gsym->can_use_relative_reloc(false)) |
| offset = (this->count_ + 1) * this->get_plt_entry_size(); |
| return this->address() + offset + gsym->plt_offset(); |
| } |
| |
| // Return the PLT address to use for a local symbol. These are always |
| // IRELATIVE relocs. |
| |
| template<int size> |
| uint64_t |
| Output_data_plt_x86_64<size>::do_address_for_local(const Relobj* object, |
| unsigned int r_sym) |
| { |
| return (this->address() |
| + (this->count_ + 1) * this->get_plt_entry_size() |
| + object->local_plt_offset(r_sym)); |
| } |
| |
| // Set the final size. |
| template<int size> |
| void |
| Output_data_plt_x86_64<size>::set_final_data_size() |
| { |
| // Number of regular and IFUNC PLT entries, plus the first entry. |
| unsigned int count = this->count_ + this->irelative_count_ + 1; |
| // Count the TLSDESC entry, if present. |
| if (this->has_tlsdesc_entry()) |
| ++count; |
| this->set_data_size(count * this->get_plt_entry_size()); |
| } |
| |
| // The first entry in the PLT for an executable. |
| |
| template<int size> |
| const unsigned char |
| Output_data_plt_x86_64_standard<size>::first_plt_entry[plt_entry_size] = |
| { |
| // From AMD64 ABI Draft 0.98, page 76 |
| 0xff, 0x35, // pushq contents of memory address |
| 0, 0, 0, 0, // replaced with address of .got + 8 |
| 0xff, 0x25, // jmp indirect |
| 0, 0, 0, 0, // replaced with address of .got + 16 |
| 0x90, 0x90, 0x90, 0x90 // noop (x4) |
| }; |
| |
| template<int size> |
| void |
| Output_data_plt_x86_64_standard<size>::do_fill_first_plt_entry( |
| unsigned char* pov, |
| typename elfcpp::Elf_types<size>::Elf_Addr got_address, |
| typename elfcpp::Elf_types<size>::Elf_Addr plt_address) |
| { |
| memcpy(pov, first_plt_entry, plt_entry_size); |
| // We do a jmp relative to the PC at the end of this instruction. |
| elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, |
| (got_address + 8 |
| - (plt_address + 6))); |
| elfcpp::Swap<32, false>::writeval(pov + 8, |
| (got_address + 16 |
| - (plt_address + 12))); |
| } |
| |
| // Subsequent entries in the PLT for an executable. |
| |
| template<int size> |
| const unsigned char |
| Output_data_plt_x86_64_standard<size>::plt_entry[plt_entry_size] = |
| { |
| // From AMD64 ABI Draft 0.98, page 76 |
| 0xff, 0x25, // jmpq indirect |
| 0, 0, 0, 0, // replaced with address of symbol in .got |
| 0x68, // pushq immediate |
| 0, 0, 0, 0, // replaced with offset into relocation table |
| 0xe9, // jmpq relative |
| 0, 0, 0, 0 // replaced with offset to start of .plt |
| }; |
| |
| template<int size> |
| unsigned int |
| Output_data_plt_x86_64_standard<size>::do_fill_plt_entry( |
| unsigned char* pov, |
| typename elfcpp::Elf_types<size>::Elf_Addr got_address, |
| typename elfcpp::Elf_types<size>::Elf_Addr plt_address, |
| unsigned int got_offset, |
| unsigned int plt_offset, |
| unsigned int plt_index) |
| { |
| // Check PC-relative offset overflow in PLT entry. |
| uint64_t plt_got_pcrel_offset = (got_address + got_offset |
| - (plt_address + plt_offset + 6)); |
| if (Bits<32>::has_overflow(plt_got_pcrel_offset)) |
| gold_error(_("PC-relative offset overflow in PLT entry %d"), |
| plt_index + 1); |
| |
| memcpy(pov, plt_entry, plt_entry_size); |
| elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, |
| plt_got_pcrel_offset); |
| |
| elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_index); |
| elfcpp::Swap<32, false>::writeval(pov + 12, |
| - (plt_offset + plt_entry_size)); |
| |
| return 6; |
| } |
| |
| // The reserved TLSDESC entry in the PLT for an executable. |
| |
| template<int size> |
| const unsigned char |
| Output_data_plt_x86_64_standard<size>::tlsdesc_plt_entry[plt_entry_size] = |
| { |
| // From Alexandre Oliva, "Thread-Local Storage Descriptors for IA32 |
| // and AMD64/EM64T", Version 0.9.4 (2005-10-10). |
| 0xff, 0x35, // pushq x(%rip) |
| 0, 0, 0, 0, // replaced with address of linkmap GOT entry (at PLTGOT + 8) |
| 0xff, 0x25, // jmpq *y(%rip) |
| 0, 0, 0, 0, // replaced with offset of reserved TLSDESC_GOT entry |
| 0x0f, 0x1f, // nop |
| 0x40, 0 |
| }; |
| |
| template<int size> |
| void |
| Output_data_plt_x86_64_standard<size>::do_fill_tlsdesc_entry( |
| unsigned char* pov, |
| typename elfcpp::Elf_types<size>::Elf_Addr got_address, |
| typename elfcpp::Elf_types<size>::Elf_Addr plt_address, |
| typename elfcpp::Elf_types<size>::Elf_Addr got_base, |
| unsigned int tlsdesc_got_offset, |
| unsigned int plt_offset) |
| { |
| memcpy(pov, tlsdesc_plt_entry, plt_entry_size); |
| elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, |
| (got_address + 8 |
| - (plt_address + plt_offset |
| + 6))); |
| elfcpp::Swap_unaligned<32, false>::writeval(pov + 8, |
| (got_base |
| + tlsdesc_got_offset |
| - (plt_address + plt_offset |
| + 12))); |
| } |
| |
| // Return the APLT address to use for a global symbol (for IBT). |
| |
| template<int size> |
| uint64_t |
| Output_data_plt_x86_64_ibt<size>::do_address_for_global(const Symbol* gsym) |
| { |
| uint64_t offset = this->aplt_offset_; |
| // Convert the PLT offset into an APLT offset. |
| unsigned int plt_offset = gsym->plt_offset(); |
| if (gsym->type() == elfcpp::STT_GNU_IFUNC |
| && gsym->can_use_relative_reloc(false)) |
| offset += this->regular_count() * aplt_entry_size; |
| else |
| plt_offset -= plt_entry_size; |
| plt_offset = plt_offset / (plt_entry_size / aplt_entry_size); |
| return this->address() + offset + plt_offset; |
| } |
| |
| // Return the PLT address to use for a local symbol. These are always |
| // IRELATIVE relocs. |
| |
| template<int size> |
| uint64_t |
| Output_data_plt_x86_64_ibt<size>::do_address_for_local(const Relobj* object, |
| unsigned int r_sym) |
| { |
| // Convert the PLT offset into an APLT offset. |
| const Sized_relobj_file<size, false>* sized_relobj = |
| static_cast<const Sized_relobj_file<size, false>*>(object); |
| const Symbol_value<size>* psymval = sized_relobj->local_symbol(r_sym); |
| unsigned int plt_offset = ((object->local_plt_offset(r_sym) |
| - (psymval->is_ifunc_symbol() |
| ? 0 : plt_entry_size)) |
| / (plt_entry_size / aplt_entry_size)); |
| return (this->address() |
| + this->aplt_offset_ |
| + this->regular_count() * aplt_entry_size |
| + plt_offset); |
| } |
| |
| // Set the final size. |
| |
| template<int size> |
| void |
| Output_data_plt_x86_64_ibt<size>::set_final_data_size() |
| { |
| // Number of regular and IFUNC PLT entries. |
| unsigned int count = this->entry_count(); |
| // Count the first entry and the TLSDESC entry, if present. |
| unsigned int extra = this->has_tlsdesc_entry() ? 2 : 1; |
| unsigned int plt_size = (count + extra) * plt_entry_size; |
| // Offset of the APLT. |
| this->aplt_offset_ = plt_size; |
| // Size of the APLT. |
| plt_size += count * aplt_entry_size; |
| this->set_data_size(plt_size); |
| } |
| |
| // The first entry in the IBT PLT. |
| |
| template<int size> |
| const unsigned char |
| Output_data_plt_x86_64_ibt<size>::first_plt_entry[plt_entry_size] = |
| { |
| 0xff, 0x35, // pushq contents of memory address |
| 0, 0, 0, 0, // replaced with address of .got + 8 |
| 0xff, 0x25, // jmp indirect |
| 0, 0, 0, 0, // replaced with address of .got + 16 |
| 0x90, 0x90, 0x90, 0x90 // noop (x4) |
| }; |
| |
| template<int size> |
| void |
| Output_data_plt_x86_64_ibt<size>::do_fill_first_plt_entry( |
| unsigned char* pov, |
| typename elfcpp::Elf_types<size>::Elf_Addr got_address, |
| typename elfcpp::Elf_types<size>::Elf_Addr plt_address) |
| { |
| // Offsets to the addresses needing relocation. |
| const unsigned int roff1 = 2; |
| const unsigned int roff2 = 8; |
| |
| memcpy(pov, first_plt_entry, plt_entry_size); |
| // We do a jmp relative to the PC at the end of this instruction. |
| elfcpp::Swap_unaligned<32, false>::writeval(pov + roff1, |
| (got_address + 8 |
| - (plt_address + roff1 + 4))); |
| elfcpp::Swap<32, false>::writeval(pov + roff2, |
| (got_address + 16 |
| - (plt_address + roff2 + 4))); |
| } |
| |
| // Subsequent entries in the IBT PLT. |
| |
| template<int size> |
| const unsigned char |
| Output_data_plt_x86_64_ibt<size>::plt_entry[plt_entry_size] = |
| { |
| // From AMD64 ABI Draft 1.0-rc1, Chapter 13. |
| 0xf3, 0x0f, 0x1e, 0xfa, // endbr64 |
| 0x68, // pushq immediate |
| 0, 0, 0, 0, // replaced with offset into relocation table |
| 0xe9, // jmpq relative |
| 0, 0, 0, 0, // replaced with offset to start of .plt |
| 0x90, 0x90 // nop |
| }; |
| |
| // Entries in the IBT Additional PLT. |
| |
| template<int size> |
| const unsigned char |
| Output_data_plt_x86_64_ibt<size>::aplt_entry[aplt_entry_size] = |
| { |
| // From AMD64 ABI Draft 1.0-rc1, Chapter 13. |
| 0xf3, 0x0f, 0x1e, 0xfa, // endbr64 |
| 0xff, 0x25, // jmpq indirect |
| 0, 0, 0, 0, // replaced with address of symbol in .got |
| 0x0f, 0x1f, 0x04, 0x00, // nop |
| 0x90, 0x90 // nop |
| }; |
| |
| template<int size> |
| unsigned int |
| Output_data_plt_x86_64_ibt<size>::do_fill_plt_entry( |
| unsigned char* pov, |
| typename elfcpp::Elf_types<size>::Elf_Addr, |
| typename elfcpp::Elf_types<size>::Elf_Addr, |
| unsigned int, |
| unsigned int plt_offset, |
| unsigned int plt_index) |
| { |
| // Offsets to the addresses needing relocation. |
| const unsigned int roff1 = 5; |
| const unsigned int roff2 = 10; |
| |
| memcpy(pov, plt_entry, plt_entry_size); |
| elfcpp::Swap_unaligned<32, false>::writeval(pov + roff1, plt_index); |
| elfcpp::Swap<32, false>::writeval(pov + roff2, -(plt_offset + roff2 + 4)); |
| return 0; |
| } |
| |
| template<int size> |
| void |
| Output_data_plt_x86_64_ibt<size>::fill_aplt_entry( |
| unsigned char* pov, |
| typename elfcpp::Elf_types<size>::Elf_Addr got_address, |
| typename elfcpp::Elf_types<size>::Elf_Addr plt_address, |
| unsigned int got_offset, |
| unsigned int plt_offset, |
| unsigned int plt_index) |
| { |
| // Offset to the address needing relocation. |
| const unsigned int roff = 6; |
| |
| // Check PC-relative offset overflow in PLT entry. |
| uint64_t plt_got_pcrel_offset = (got_address + got_offset |
| - (plt_address + plt_offset + roff + 4)); |
| if (Bits<32>::has_overflow(plt_got_pcrel_offset)) |
| gold_error(_("PC-relative offset overflow in APLT entry %d"), |
| plt_index + 1); |
| |
| memcpy(pov, aplt_entry, aplt_entry_size); |
| elfcpp::Swap_unaligned<32, false>::writeval(pov + roff, plt_got_pcrel_offset); |
| } |
| |
| // The reserved TLSDESC entry in the IBT PLT for an executable. |
| |
| template<int size> |
| const unsigned char |
| Output_data_plt_x86_64_ibt<size>::tlsdesc_plt_entry[plt_entry_size] = |
| { |
| // From Alexandre Oliva, "Thread-Local Storage Descriptors for IA32 |
| // and AMD64/EM64T", Version 0.9.4 (2005-10-10). |
| 0xf3, 0x0f, 0x1e, 0xfa, // endbr64 |
| 0xff, 0x35, // pushq x(%rip) |
| 0, 0, 0, 0, // replaced with address of linkmap GOT entry (at PLTGOT + 8) |
| 0xff, 0x25, // jmpq *y(%rip) |
| 0, 0, 0, 0, // replaced with offset of reserved TLSDESC_GOT entry |
| }; |
| |
| template<int size> |
| void |
| Output_data_plt_x86_64_ibt<size>::do_fill_tlsdesc_entry( |
| unsigned char* pov, |
| typename elfcpp::Elf_types<size>::Elf_Addr got_address, |
| typename elfcpp::Elf_types<size>::Elf_Addr plt_address, |
| typename elfcpp::Elf_types<size>::Elf_Addr got_base, |
| unsigned int tlsdesc_got_offset, |
| unsigned int plt_offset) |
| { |
| memcpy(pov, tlsdesc_plt_entry, plt_entry_size); |
| elfcpp::Swap_unaligned<32, false>::writeval(pov + 6, |
| (got_address + 8 |
| - (plt_address + plt_offset |
| + 10))); |
| elfcpp::Swap_unaligned<32, false>::writeval(pov + 12, |
| (got_base |
| + tlsdesc_got_offset |
| - (plt_address + plt_offset |
| + 16))); |
| } |
| |
| // The .eh_frame unwind information for the PLT. |
| |
| template<int size> |
| const unsigned char |
| Output_data_plt_x86_64<size>::plt_eh_frame_cie[plt_eh_frame_cie_size] = |
| { |
| 1, // CIE version. |
| 'z', // Augmentation: augmentation size included. |
| 'R', // Augmentation: FDE encoding included. |
| '\0', // End of augmentation string. |
| 1, // Code alignment factor. |
| 0x78, // Data alignment factor. |
| 16, // Return address column. |
| 1, // Augmentation size. |
| (elfcpp::DW_EH_PE_pcrel // FDE encoding. |
| | elfcpp::DW_EH_PE_sdata4), |
| elfcpp::DW_CFA_def_cfa, 7, 8, // DW_CFA_def_cfa: r7 (rsp) ofs 8. |
| elfcpp::DW_CFA_offset + 16, 1,// DW_CFA_offset: r16 (rip) at cfa-8. |
| elfcpp::DW_CFA_nop, // Align to 16 bytes. |
| elfcpp::DW_CFA_nop |
| }; |
| |
| template<int size> |
| const unsigned char |
| Output_data_plt_x86_64_standard<size>::plt_eh_frame_fde[plt_eh_frame_fde_size] = |
| { |
| 0, 0, 0, 0, // Replaced with offset to .plt. |
| 0, 0, 0, 0, // Replaced with size of .plt. |
| 0, // Augmentation size. |
| elfcpp::DW_CFA_def_cfa_offset, 16, // DW_CFA_def_cfa_offset: 16. |
| elfcpp::DW_CFA_advance_loc + 6, // Advance 6 to __PLT__ + 6. |
| elfcpp::DW_CFA_def_cfa_offset, 24, // DW_CFA_def_cfa_offset: 24. |
| elfcpp::DW_CFA_advance_loc + 10, // Advance 10 to __PLT__ + 16. |
| elfcpp::DW_CFA_def_cfa_expression, // DW_CFA_def_cfa_expression. |
| 11, // Block length. |
| elfcpp::DW_OP_breg7, 8, // Push %rsp + 8. |
| elfcpp::DW_OP_breg16, 0, // Push %rip. |
| elfcpp::DW_OP_lit15, // Push 0xf. |
| elfcpp::DW_OP_and, // & (%rip & 0xf). |
| elfcpp::DW_OP_lit11, // Push 0xb. |
| elfcpp::DW_OP_ge, // >= ((%rip & 0xf) >= 0xb) |
| elfcpp::DW_OP_lit3, // Push 3. |
| elfcpp::DW_OP_shl, // << (((%rip & 0xf) >= 0xb) << 3) |
| elfcpp::DW_OP_plus, // + ((((%rip&0xf)>=0xb)<<3)+%rsp+8 |
| elfcpp::DW_CFA_nop, // Align to 32 bytes. |
| elfcpp::DW_CFA_nop, |
| elfcpp::DW_CFA_nop, |
| elfcpp::DW_CFA_nop |
| }; |
| |
| // The .eh_frame unwind information for the PLT. |
| template<int size> |
| const unsigned char |
| Output_data_plt_x86_64_ibt<size>::plt_eh_frame_fde[plt_eh_frame_fde_size] = |
| { |
| 0, 0, 0, 0, // Replaced with offset to .plt. |
| 0, 0, 0, 0, // Replaced with size of .plt. |
| 0, // Augmentation size. |
| elfcpp::DW_CFA_def_cfa_offset, 16, // DW_CFA_def_cfa_offset: 16. |
| elfcpp::DW_CFA_advance_loc + 6, // Advance 6 to __PLT__ + 6. |
| elfcpp::DW_CFA_def_cfa_offset, 24, // DW_CFA_def_cfa_offset: 24. |
| elfcpp::DW_CFA_advance_loc + 10, // Advance 10 to __PLT__ + 16. |
| elfcpp::DW_CFA_def_cfa_expression, // DW_CFA_def_cfa_expression. |
| 11, // Block length. |
| elfcpp::DW_OP_breg7, 8, // Push %rsp + 8. |
| elfcpp::DW_OP_breg16, 0, // Push %rip. |
| elfcpp::DW_OP_lit15, // Push 0xf. |
| elfcpp::DW_OP_and, // & (%rip & 0xf). |
| elfcpp::DW_OP_lit9, // Push 9. |
| elfcpp::DW_OP_ge, // >= ((%rip & 0xf) >= 9) |
| elfcpp::DW_OP_lit3, // Push 3. |
| elfcpp::DW_OP_shl, // << (((%rip & 0xf) >= 9) << 3) |
| elfcpp::DW_OP_plus, // + ((((%rip&0xf)>=9)<<3)+%rsp+8 |
| elfcpp::DW_CFA_nop, // Align to 32 bytes. |
| elfcpp::DW_CFA_nop, |
| elfcpp::DW_CFA_nop, |
| elfcpp::DW_CFA_nop |
| }; |
| |
| // Write out the PLT. This uses the hand-coded instructions above, |
| // and adjusts them as needed. This is specified by the AMD64 ABI. |
| |
| template<int size> |
| void |
| Output_data_plt_x86_64<size>::do_write(Output_file* of) |
| { |
| const off_t offset = this->offset(); |
| const section_size_type oview_size = |
| convert_to_section_size_type(this->data_size()); |
| unsigned char* const oview = of->get_output_view(offset, oview_size); |
| |
| const off_t got_file_offset = this->got_plt_->offset(); |
| gold_assert(parameters->incremental_update() |
| || (got_file_offset + this->got_plt_->data_size() |
| == this->got_irelative_->offset())); |
| const section_size_type got_size = |
| convert_to_section_size_type(this->got_plt_->data_size() |
| + this->got_irelative_->data_size()); |
| unsigned char* const got_view = of->get_output_view(got_file_offset, |
| got_size); |
| |
| unsigned char* pov = oview; |
| |
| // The base address of the .plt section. |
| typename elfcpp::Elf_types<size>::Elf_Addr plt_address = this->address(); |
| // The base address of the .got section. |
| typename elfcpp::Elf_types<size>::Elf_Addr got_base = this->got_->address(); |
| // The base address of the PLT portion of the .got section, |
| // which is where the GOT pointer will point, and where the |
| // three reserved GOT entries are located. |
| typename elfcpp::Elf_types<size>::Elf_Addr got_address |
| = this->got_plt_->address(); |
| |
| this->fill_first_plt_entry(pov, got_address, plt_address); |
| pov += this->get_plt_entry_size(); |
| |
| // The first three entries in the GOT are reserved, and are written |
| // by Output_data_got_plt_x86_64::do_write. |
| unsigned char* got_pov = got_view + 24; |
| |
| unsigned int plt_offset = this->get_plt_entry_size(); |
| unsigned int got_offset = 24; |
| const unsigned int count = this->count_ + this->irelative_count_; |
| for (unsigned int plt_index = 0; |
| plt_index < count; |
| ++plt_index, |
| pov += this->get_plt_entry_size(), |
| got_pov += 8, |
| plt_offset += this->get_plt_entry_size(), |
| got_offset += 8) |
| { |
| // Set and adjust the PLT entry itself. |
| unsigned int lazy_offset = this->fill_plt_entry(pov, |
| got_address, plt_address, |
| got_offset, plt_offset, |
| plt_index); |
| |
| // Set the entry in the GOT. |
| elfcpp::Swap<64, false>::writeval(got_pov, |
| plt_address + plt_offset + lazy_offset); |
| } |
| |
| if (this->has_tlsdesc_entry()) |
| { |
| // Set and adjust the reserved TLSDESC PLT entry. |
| unsigned int tlsdesc_got_offset = this->get_tlsdesc_got_offset(); |
| this->fill_tlsdesc_entry(pov, got_address, plt_address, got_base, |
| tlsdesc_got_offset, plt_offset); |
| pov += this->get_plt_entry_size(); |
| } |
| |
| gold_assert(static_cast<section_size_type>(pov - oview) == oview_size); |
| gold_assert(static_cast<section_size_type>(got_pov - got_view) == got_size); |
| |
| of->write_output_view(offset, oview_size, oview); |
| of->write_output_view(got_file_offset, got_size, got_view); |
| } |
| |
| // Write out the IBT PLT. |
| |
| template<int size> |
| void |
| Output_data_plt_x86_64_ibt<size>::do_write(Output_file* of) |
| { |
| const off_t offset = this->offset(); |
| const section_size_type oview_size = |
| convert_to_section_size_type(this->data_size()); |
| unsigned char* const oview = of->get_output_view(offset, oview_size); |
| |
| Output_data_got<64, false>* got = this->got(); |
| Output_data_got_plt_x86_64* got_plt = this->got_plt(); |
| Output_data_space* got_irelative = this->got_irelative(); |
| |
| const off_t got_file_offset = got_plt->offset(); |
| gold_assert(parameters->incremental_update() |
| || (got_file_offset + got_plt->data_size() |
| == got_irelative->offset())); |
| const section_size_type got_size = |
| convert_to_section_size_type(got_plt->data_size() |
| + got_irelative->data_size()); |
| unsigned char* const got_view = of->get_output_view(got_file_offset, |
| got_size); |
| |
| unsigned char* pov = oview; |
| |
| // The base address of the .plt section. |
| elfcpp::Elf_types<64>::Elf_Addr plt_address = this->address(); |
| // The base address of the .got section. |
| elfcpp::Elf_types<64>::Elf_Addr got_base = got->address(); |
| // The base address of the PLT portion of the .got section, |
| // which is where the GOT pointer will point, and where the |
| // three reserved GOT entries are located. |
| elfcpp::Elf_types<64>::Elf_Addr got_address = got_plt->address(); |
| |
| this->fill_first_plt_entry(pov, got_address, plt_address); |
| pov += plt_entry_size; |
| |
| // The first three entries in the GOT are reserved, and are written |
| // by Output_data_got_plt_x86_64::do_write. |
| unsigned char* got_pov = got_view + 24; |
| |
| unsigned int plt_offset = plt_entry_size; |
| unsigned int got_offset = 24; |
| const unsigned int count = this->entry_count(); |
| for (unsigned int plt_index = 0; |
| plt_index < count; |
| ++plt_index, |
| pov += plt_entry_size, |
| got_pov += 8, |
| plt_offset += plt_entry_size, |
| got_offset += 8) |
| { |
| // Set and adjust the PLT entry itself. |
| unsigned int lazy_offset = this->fill_plt_entry(pov, |
| got_address, plt_address, |
| got_offset, plt_offset, |
| plt_index); |
| |
| // Set the entry in the GOT. |
| elfcpp::Swap<64, false>::writeval(got_pov, |
| plt_address + plt_offset + lazy_offset); |
| } |
| |
| if (this->has_tlsdesc_entry()) |
| { |
| // Set and adjust the reserved TLSDESC PLT entry. |
| unsigned int tlsdesc_got_offset = this->get_tlsdesc_got_offset(); |
| this->fill_tlsdesc_entry(pov, got_address, plt_address, got_base, |
| tlsdesc_got_offset, plt_offset); |
| pov += this->get_plt_entry_size(); |
| plt_offset += plt_entry_size; |
| } |
| |
| // Write the additional PLT. |
| got_offset = 24; |
| for (unsigned int plt_index = 0; |
| plt_index < count; |
| ++plt_index, |
| pov += aplt_entry_size, |
| plt_offset += aplt_entry_size, |
| got_offset += 8) |
| { |
| // Set and adjust the APLT entry. |
| this->fill_aplt_entry(pov, got_address, plt_address, got_offset, |
| plt_offset, plt_index); |
| } |
| |
| gold_assert(static_cast<section_size_type>(pov - oview) == oview_size); |
| gold_assert(static_cast<section_size_type>(got_pov - got_view) == got_size); |
| |
| of->write_output_view(offset, oview_size, oview); |
| of->write_output_view(got_file_offset, got_size, got_view); |
| } |
| |
| // Create the PLT section. |
| |
| template<int size> |
| void |
| Target_x86_64<size>::make_plt_section(Symbol_table* symtab, Layout* layout) |
| { |
| if (this->plt_ == NULL) |
| { |
| // Create the GOT sections first. |
| this->got_section(symtab, layout); |
| |
| this->plt_ = this->make_data_plt(layout, this->got_, this->got_plt_, |
| this->got_irelative_); |
| |
| // Add unwind information if requested. |
| if (parameters->options().ld_generated_unwind_info()) |
| this->plt_->add_eh_frame(layout); |
| |
| layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS, |
| (elfcpp::SHF_ALLOC |
| | elfcpp::SHF_EXECINSTR), |
| this->plt_, ORDER_PLT, false); |
| |
| // Make the sh_info field of .rela.plt point to .plt. |
| Output_section* rela_plt_os = this->plt_->rela_plt()->output_section(); |
| rela_plt_os->set_info_section(this->plt_->output_section()); |
| } |
| } |
| |
| template<> |
| Output_data_plt_x86_64<32>* |
| Target_x86_64<32>::do_make_data_plt(Layout* layout, |
| Output_data_got<64, false>* got, |
| Output_data_got_plt_x86_64* got_plt, |
| Output_data_space* got_irelative) |
| { |
| if (this->feature_1_ & elfcpp::GNU_PROPERTY_X86_FEATURE_1_IBT) |
| return new Output_data_plt_x86_64_ibt<32>(layout, got, got_plt, |
| got_irelative); |
| return new Output_data_plt_x86_64_standard<32>(layout, got, got_plt, |
| got_irelative); |
| } |
| |
| template<> |
| Output_data_plt_x86_64<64>* |
| Target_x86_64<64>::do_make_data_plt(Layout* layout, |
| Output_data_got<64, false>* got, |
| Output_data_got_plt_x86_64* got_plt, |
| Output_data_space* got_irelative) |
| { |
| if (this->feature_1_ & elfcpp::GNU_PROPERTY_X86_FEATURE_1_IBT) |
| return new Output_data_plt_x86_64_ibt<64>(layout, got, got_plt, |
| got_irelative); |
| else |
| return new Output_data_plt_x86_64_standard<64>(layout, got, got_plt, |
| got_irelative); |
| } |
| |
| template<> |
| Output_data_plt_x86_64<32>* |
| Target_x86_64<32>::do_make_data_plt(Layout* layout, |
| Output_data_got<64, false>* got, |
| Output_data_got_plt_x86_64* got_plt, |
| Output_data_space* got_irelative, |
| unsigned int plt_count) |
| { |
| if (this->feature_1_ & elfcpp::GNU_PROPERTY_X86_FEATURE_1_IBT) |
| return new Output_data_plt_x86_64_ibt<32>(layout, got, got_plt, |
| got_irelative, plt_count); |
| return new Output_data_plt_x86_64_standard<32>(layout, got, got_plt, |
| got_irelative, plt_count); |
| } |
| |
| template<> |
| Output_data_plt_x86_64<64>* |
| Target_x86_64<64>::do_make_data_plt(Layout* layout, |
| Output_data_got<64, false>* got, |
| Output_data_got_plt_x86_64* got_plt, |
| Output_data_space* got_irelative, |
| unsigned int plt_count) |
| { |
| if (this->feature_1_ & elfcpp::GNU_PROPERTY_X86_FEATURE_1_IBT) |
| return new Output_data_plt_x86_64_ibt<64>(layout, got, got_plt, |
| got_irelative, plt_count); |
| else |
| return new Output_data_plt_x86_64_standard<64>(layout, got, got_plt, |
| got_irelative, |
| plt_count); |
| } |
| |
| // Return the section for TLSDESC relocations. |
| |
| template<int size> |
| typename Target_x86_64<size>::Reloc_section* |
| Target_x86_64<size>::rela_tlsdesc_section(Layout* layout) const |
| { |
| return this->plt_section()->rela_tlsdesc(layout); |
| } |
| |
| // Create a PLT entry for a global symbol. |
| |
| template<int size> |
| void |
| Target_x86_64<size>::make_plt_entry(Symbol_table* symtab, Layout* layout, |
| Symbol* gsym) |
| { |
| if (gsym->has_plt_offset()) |
| return; |
| |
| if (this->plt_ == NULL) |
| this->make_plt_section(symtab, layout); |
| |
| this->plt_->add_entry(symtab, layout, gsym); |
| } |
| |
| // Make a PLT entry for a local STT_GNU_IFUNC symbol. |
| |
| template<int size> |
| void |
| Target_x86_64<size>::make_local_ifunc_plt_entry( |
| Symbol_table* symtab, Layout* layout, |
| Sized_relobj_file<size, false>* relobj, |
| unsigned int local_sym_index) |
| { |
| if (relobj->local_has_plt_offset(local_sym_index)) |
| return; |
| if (this->plt_ == NULL) |
| this->make_plt_section(symtab, layout); |
| unsigned int plt_offset = this->plt_->add_local_ifunc_entry(symtab, layout, |
| relobj, |
| local_sym_index); |
| relobj->set_local_plt_offset(local_sym_index, plt_offset); |
| } |
| |
| // Return the number of entries in the PLT. |
| |
| template<int size> |
| unsigned int |
| Target_x86_64<size>::plt_entry_count() const |
| { |
| if (this->plt_ == NULL) |
| return 0; |
| return this->plt_->entry_count(); |
| } |
| |
| // Return the offset of the first non-reserved PLT entry. |
| |
| template<int size> |
| unsigned int |
| Target_x86_64<size>::first_plt_entry_offset() const |
| { |
| if (this->plt_ == NULL) |
| return 0; |
| return this->plt_->first_plt_entry_offset(); |
| } |
| |
| // Return the size of each PLT entry. |
| |
| template<int size> |
| unsigned int |
| Target_x86_64<size>::plt_entry_size() const |
| { |
| if (this->plt_ == NULL) |
| return 0; |
| return this->plt_->get_plt_entry_size(); |
| } |
| |
| // Create the GOT and PLT sections for an incremental update. |
| |
| template<int size> |
| Output_data_got_base* |
| Target_x86_64<size>::init_got_plt_for_update(Symbol_table* symtab, |
| Layout* layout, |
| unsigned int got_count, |
| unsigned int plt_count) |
| { |
| gold_assert(this->got_ == NULL); |
| |
| this->got_ = new Output_data_got<64, false>(got_count * 8); |
| layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS, |
| (elfcpp::SHF_ALLOC |
| | elfcpp::SHF_WRITE), |
| this->got_, ORDER_RELRO_LAST, |
| true); |
| |
| // Add the three reserved entries. |
| this->got_plt_ = new Output_data_got_plt_x86_64(layout, (plt_count + 3) * 8); |
| layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS, |
| (elfcpp::SHF_ALLOC |
| | elfcpp::SHF_WRITE), |
| this->got_plt_, ORDER_NON_RELRO_FIRST, |
| false); |
| |
| // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT. |
| this->global_offset_table_ = |
| symtab->define_in_output_data("_GLOBAL_OFFSET_TABLE_", NULL, |
| Symbol_table::PREDEFINED, |
| this->got_plt_, |
| 0, 0, elfcpp::STT_OBJECT, |
| elfcpp::STB_LOCAL, |
| elfcpp::STV_HIDDEN, 0, |
| false, false); |
| |
| // If there are any TLSDESC relocations, they get GOT entries in |
| // .got.plt after the jump slot entries. |
| // FIXME: Get the count for TLSDESC entries. |
| this->got_tlsdesc_ = new Output_data_got<64, false>(0); |
| layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS, |
| elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE, |
| this->got_tlsdesc_, |
| ORDER_NON_RELRO_FIRST, false); |
| |
| // If there are any IRELATIVE relocations, they get GOT entries in |
| // .got.plt after the jump slot and TLSDESC entries. |
| this->got_irelative_ = new Output_data_space(0, 8, "** GOT IRELATIVE PLT"); |
| layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS, |
| elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE, |
| this->got_irelative_, |
| ORDER_NON_RELRO_FIRST, false); |
| |
| // Create the PLT section. |
| this->plt_ = this->make_data_plt(layout, this->got_, |
| this->got_plt_, |
| this->got_irelative_, |
| plt_count); |
| |
| // Add unwind information if requested. |
| if (parameters->options().ld_generated_unwind_info()) |
| this->plt_->add_eh_frame(layout); |
| |
| layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS, |
| elfcpp::SHF_ALLOC | elfcpp::SHF_EXECINSTR, |
| this->plt_, ORDER_PLT, false); |
| |
| // Make the sh_info field of .rela.plt point to .plt. |
| Output_section* rela_plt_os = this->plt_->rela_plt()->output_section(); |
| rela_plt_os->set_info_section(this->plt_->output_section()); |
| |
| // Create the rela_dyn section. |
| this->rela_dyn_section(layout); |
| |
| return this->got_; |
| } |
| |
| // Reserve a GOT entry for a local symbol, and regenerate any |
| // necessary dynamic relocations. |
| |
| template<int size> |
| void |
| Target_x86_64<size>::reserve_local_got_entry( |
| unsigned int got_index, |
| Sized_relobj<size, false>* obj, |
| unsigned int r_sym, |
| unsigned int got_type) |
| { |
| unsigned int got_offset = got_index * 8; |
| Reloc_section* rela_dyn = this->rela_dyn_section(NULL); |
| |
| this->got_->reserve_local(got_index, obj, r_sym, got_type); |
| switch (got_type) |
| { |
| case GOT_TYPE_STANDARD: |
| if (parameters->options().output_is_position_independent()) |
| rela_dyn->add_local_relative(obj, r_sym, elfcpp::R_X86_64_RELATIVE, |
| this->got_, got_offset, 0, false); |
| break; |
| case GOT_TYPE_TLS_OFFSET: |
| rela_dyn->add_local(obj, r_sym, elfcpp::R_X86_64_TPOFF64, |
| this->got_, got_offset, 0); |
| break; |
| case GOT_TYPE_TLS_PAIR: |
| this->got_->reserve_slot(got_index + 1); |
| rela_dyn->add_local(obj, r_sym, elfcpp::R_X86_64_DTPMOD64, |
| this->got_, got_offset, 0); |
| break; |
| case GOT_TYPE_TLS_DESC: |
| gold_fatal(_("TLS_DESC not yet supported for incremental linking")); |
| // this->got_->reserve_slot(got_index + 1); |
| // rela_dyn->add_target_specific(elfcpp::R_X86_64_TLSDESC, arg, |
| // this->got_, got_offset, 0); |
| break; |
| default: |
| gold_unreachable(); |
| } |
| } |
| |
| // Reserve a GOT entry for a global symbol, and regenerate any |
| // necessary dynamic relocations. |
| |
| template<int size> |
| void |
| Target_x86_64<size>::reserve_global_got_entry(unsigned int got_index, |
| Symbol* gsym, |
| unsigned int got_type) |
| { |
| unsigned int got_offset = got_index * 8; |
| Reloc_section* rela_dyn = this->rela_dyn_section(NULL); |
| |
| this->got_->reserve_global(got_index, gsym, got_type); |
| switch (got_type) |
| { |
| case GOT_TYPE_STANDARD: |
| if (!gsym->final_value_is_known()) |
| { |
| if (gsym->is_from_dynobj() |
| || gsym->is_undefined() |
| || gsym->is_preemptible() |
| || gsym->type() == elfcpp::STT_GNU_IFUNC) |
| rela_dyn->add_global(gsym, elfcpp::R_X86_64_GLOB_DAT, |
| this->got_, got_offset, 0); |
| else |
| rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_RELATIVE, |
| this->got_, got_offset, 0, false); |
| } |
| break; |
| case GOT_TYPE_TLS_OFFSET: |
| rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_TPOFF64, |
| this->got_, got_offset, 0, false); |
| break; |
| case GOT_TYPE_TLS_PAIR: |
| this->got_->reserve_slot(got_index + 1); |
| rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_DTPMOD64, |
| this->got_, got_offset, 0, false); |
| rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_DTPOFF64, |
| this->got_, got_offset + 8, 0, false); |
| break; |
| case GOT_TYPE_TLS_DESC: |
| this->got_->reserve_slot(got_index + 1); |
| rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_TLSDESC, |
| this->got_, got_offset, 0, false); |
| break; |
| default: |
| gold_unreachable(); |
| } |
| } |
| |
| // Register an existing PLT entry for a global symbol. |
| |
| template<int size> |
| void |
| Target_x86_64<size>::register_global_plt_entry(Symbol_table* symtab, |
| Layout* layout, |
| unsigned int plt_index, |
| Symbol* gsym) |
| { |
| gold_assert(this->plt_ != NULL); |
| gold_assert(!gsym->has_plt_offset()); |
| |
| this->plt_->reserve_slot(plt_index); |
| |
| gsym->set_plt_offset((plt_index + 1) * this->plt_entry_size()); |
| |
| unsigned int got_offset = (plt_index + 3) * 8; |
| this->plt_->add_relocation(symtab, layout, gsym, got_offset); |
| } |
| |
| // Force a COPY relocation for a given symbol. |
| |
| template<int size> |
| void |
| Target_x86_64<size>::emit_copy_reloc( |
| Symbol_table* symtab, Symbol* sym, Output_section* os, off_t offset) |
| { |
| this->copy_relocs_.emit_copy_reloc(symtab, |
| symtab->get_sized_symbol<size>(sym), |
| os, |
| offset, |
| this->rela_dyn_section(NULL)); |
| } |
| |
| // Define the _TLS_MODULE_BASE_ symbol in the TLS segment. |
| |
| template<int size> |
| void |
| Target_x86_64<size>::define_tls_base_symbol(Symbol_table* symtab, |
| Layout* layout) |
| { |
| if (this->tls_base_symbol_defined_) |
| return; |
| |
| Output_segment* tls_segment = layout->tls_segment(); |
| if (tls_segment != NULL) |
| { |
| bool is_exec = parameters->options().output_is_executable(); |
| symtab->define_in_output_segment("_TLS_MODULE_BASE_", NULL, |
| Symbol_table::PREDEFINED, |
| tls_segment, 0, 0, |
| elfcpp::STT_TLS, |
| elfcpp::STB_LOCAL, |
| elfcpp::STV_HIDDEN, 0, |
| (is_exec |
| ? Symbol::SEGMENT_END |
| : Symbol::SEGMENT_START), |
| true); |
| } |
| this->tls_base_symbol_defined_ = true; |
| } |
| |
| // Create the reserved PLT and GOT entries for the TLS descriptor resolver. |
| |
| template<int size> |
| void |
| Target_x86_64<size>::reserve_tlsdesc_entries(Symbol_table* symtab, |
| Layout* layout) |
| { |
| if (this->plt_ == NULL) |
| this->make_plt_section(symtab, layout); |
| |
| if (!this->plt_->has_tlsdesc_entry()) |
| { |
| // Allocate the TLSDESC_GOT entry. |
| Output_data_got<64, false>* got = this->got_section(symtab, layout); |
| unsigned int got_offset = got->add_constant(0); |
| |
| // Allocate the TLSDESC_PLT entry. |
| this->plt_->reserve_tlsdesc_entry(got_offset); |
| } |
| } |
| |
| // Create a GOT entry for the TLS module index. |
| |
| template<int size> |
| unsigned int |
| Target_x86_64<size>::got_mod_index_entry(Symbol_table* symtab, Layout* layout, |
| Sized_relobj_file<size, false>* object) |
| { |
| if (this->got_mod_index_offset_ == -1U) |
| { |
| gold_assert(symtab != NULL && layout != NULL && object != NULL); |
| Reloc_section* rela_dyn = this->rela_dyn_section(layout); |
| Output_data_got<64, false>* got = this->got_section(symtab, layout); |
| unsigned int got_offset = got->add_constant(0); |
| rela_dyn->add_local(object, 0, elfcpp::R_X86_64_DTPMOD64, got, |
| got_offset, 0); |
| got->add_constant(0); |
| this->got_mod_index_offset_ = got_offset; |
| } |
| return this->got_mod_index_offset_; |
| } |
| |
| // Optimize the TLS relocation type based on what we know about the |
| // symbol. IS_FINAL is true if the final address of this symbol is |
| // known at link time. RELOC_VIEW points to the relocation offset. |
| |
| template<int size> |
| tls::Tls_optimization |
| Target_x86_64<size>::optimize_tls_reloc(bool is_final, int r_type, |
| size_t r_offset, |
| const unsigned char* reloc_view) |
| { |
| // If we are generating a shared library, then we can't do anything |
| // in the linker. |
| if (parameters->options().shared()) |
| return tls::TLSOPT_NONE; |
| |
| switch (r_type) |
| { |
| case elfcpp::R_X86_64_CODE_4_GOTPC32_TLSDESC: |
| if (r_offset <= 4 || *(reloc_view - 4) != 0xd5) |
| return tls::TLSOPT_NONE; |
| // Fall through. |
| case elfcpp::R_X86_64_TLSGD: |
| case elfcpp::R_X86_64_GOTPC32_TLSDESC: |
| case elfcpp::R_X86_64_TLSDESC_CALL: |
| // These are General-Dynamic which permits fully general TLS |
| // access. Since we know that we are generating an executable, |
| // we can convert this to Initial-Exec. If we also know that |
| // this is a local symbol, we can further switch to Local-Exec. |
| if (is_final) |
| return tls::TLSOPT_TO_LE; |
| return tls::TLSOPT_TO_IE; |
| |
| case elfcpp::R_X86_64_TLSLD: |
| // This is Local-Dynamic, which refers to a local symbol in the |
| // dynamic TLS block. Since we know that we generating an |
| // executable, we can switch to Local-Exec. |
| return tls::TLSOPT_TO_LE; |
| |
| case elfcpp::R_X86_64_DTPOFF32: |
| case elfcpp::R_X86_64_DTPOFF64: |
| // Another Local-Dynamic reloc. |
| return tls::TLSOPT_TO_LE; |
| |
| case elfcpp::R_X86_64_CODE_6_GOTTPOFF: |
| if (r_offset <= 6 || *(reloc_view - 6) != 0x62) |
| return tls::TLSOPT_NONE; |
| goto handle_gottpoff; |
| |
| case elfcpp::R_X86_64_CODE_4_GOTTPOFF: |
| if (r_offset <= 4 || *(reloc_view - 4) != 0xd5) |
| return tls::TLSOPT_NONE; |
| // Fall through. |
| case elfcpp::R_X86_64_GOTTPOFF: |
| // These are Initial-Exec relocs which get the thread offset |
| // from the GOT. If we know that we are linking against the |
| // local symbol, we can switch to Local-Exec, which links the |
| // thread offset into the instruction. |
| handle_gottpoff: |
| if (is_final) |
| return tls::TLSOPT_TO_LE; |
| return tls::TLSOPT_NONE; |
| |
| case elfcpp::R_X86_64_TPOFF32: |
| // When we already have Local-Exec, there is nothing further we |
| // can do. |
| return tls::TLSOPT_NONE; |
| |
| default: |
| gold_unreachable(); |
| } |
| } |
| |
| // Get the Reference_flags for a particular relocation. |
| |
| template<int size> |
| int |
| Target_x86_64<size>::Scan::get_reference_flags(unsigned int r_type) |
| { |
| switch (r_type) |
| { |
| case elfcpp::R_X86_64_NONE: |
| case elfcpp::R_X86_64_GNU_VTINHERIT: |
| case elfcpp::R_X86_64_GNU_VTENTRY: |
| case elfcpp::R_X86_64_GOTPC32: |
| case elfcpp::R_X86_64_GOTPC64: |
| // No symbol reference. |
| return 0; |
| |
| case elfcpp::R_X86_64_64: |
| case elfcpp::R_X86_64_32: |
| case elfcpp::R_X86_64_32S: |
| case elfcpp::R_X86_64_16: |
| case elfcpp::R_X86_64_8: |
| return Symbol::ABSOLUTE_REF; |
| |
| case elfcpp::R_X86_64_PC64: |
| case elfcpp::R_X86_64_PC32: |
| case elfcpp::R_X86_64_PC16: |
| case elfcpp::R_X86_64_PC8: |
| case elfcpp::R_X86_64_GOTOFF64: |
| return Symbol::RELATIVE_REF; |
| |
| case elfcpp::R_X86_64_PLT32: |
| case elfcpp::R_X86_64_PLTOFF64: |
| return Symbol::FUNCTION_CALL | Symbol::RELATIVE_REF; |
| |
| case elfcpp::R_X86_64_GOT64: |
| case elfcpp::R_X86_64_GOT32: |
| case elfcpp::R_X86_64_GOTPCREL64: |
| case elfcpp::R_X86_64_GOTPCREL: |
| case elfcpp::R_X86_64_GOTPCRELX: |
| case elfcpp::R_X86_64_REX_GOTPCRELX: |
| case elfcpp::R_X86_64_CODE_4_GOTPCRELX: |
| case elfcpp::R_X86_64_GOTPLT64: |
| // Absolute in GOT. |
|