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- // x86_64.cc -- x86_64 target support for gold.
- // Copyright (C) 2006-2022 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];
- };
- class Output_data_plt_x86_64_bnd : public Output_data_plt_x86_64<64>
- {
- public:
- Output_data_plt_x86_64_bnd(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<64>(layout, plt_entry_size,
- got, got_plt, got_irelative),
- aplt_offset_(0)
- { }
- Output_data_plt_x86_64_bnd(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<64>(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,
- elfcpp::Elf_types<64>::Elf_Addr got_addr,
- elfcpp::Elf_types<64>::Elf_Addr plt_addr);
- virtual unsigned int
- do_fill_plt_entry(unsigned char* pov,
- elfcpp::Elf_types<64>::Elf_Addr got_address,
- elfcpp::Elf_types<64>::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,
- elfcpp::Elf_types<64>::Elf_Addr got_address,
- elfcpp::Elf_types<64>::Elf_Addr plt_address,
- elfcpp::Elf_types<64>::Elf_Addr got_base,
- unsigned int tlsdesc_got_offset,
- unsigned int plt_offset);
- void
- fill_aplt_entry(unsigned char* pov,
- elfcpp::Elf_types<64>::Elf_Addr got_address,
- elfcpp::Elf_types<64>::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 BND 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 = 8;
- // 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];
- };
- // 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 BND 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)
- 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);
- // 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 -z bndplt).
- uint64_t
- Output_data_plt_x86_64_bnd::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.
- uint64_t
- Output_data_plt_x86_64_bnd::do_address_for_local(const Relobj* object,
- unsigned int r_sym)
- {
- // Convert the PLT offset into an APLT offset.
- const Sized_relobj_file<64, false>* sized_relobj =
- static_cast<const Sized_relobj_file<64, false>*>(object);
- const Symbol_value<64>* 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.
- void
- Output_data_plt_x86_64_bnd::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 BND PLT.
- const unsigned char
- Output_data_plt_x86_64_bnd::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
- 0xf2, 0xff, 0x25, // bnd jmp indirect
- 0, 0, 0, 0, // replaced with address of .got + 16
- 0x0f, 0x1f, 0x00 // nop
- };
- void
- Output_data_plt_x86_64_bnd::do_fill_first_plt_entry(
- unsigned char* pov,
- elfcpp::Elf_types<64>::Elf_Addr got_address,
- elfcpp::Elf_types<64>::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 + 9,
- (got_address + 16
- - (plt_address + 13)));
- }
- // Subsequent entries in the BND PLT.
- const unsigned char
- Output_data_plt_x86_64_bnd::plt_entry[plt_entry_size] =
- {
- // From AMD64 ABI Draft 0.99.8, page 139
- 0x68, // pushq immediate
- 0, 0, 0, 0, // replaced with offset into relocation table
- 0xf2, 0xe9, // bnd jmpq relative
- 0, 0, 0, 0, // replaced with offset to start of .plt
- 0x0f, 0x1f, 0x44, 0, 0 // nop
- };
- // Entries in the BND Additional PLT.
- const unsigned char
- Output_data_plt_x86_64_bnd::aplt_entry[aplt_entry_size] =
- {
- // From AMD64 ABI Draft 0.99.8, page 139
- 0xf2, 0xff, 0x25, // bnd jmpq indirect
- 0, 0, 0, 0, // replaced with address of symbol in .got
- 0x90, // nop
- };
- unsigned int
- Output_data_plt_x86_64_bnd::do_fill_plt_entry(
- unsigned char* pov,
- elfcpp::Elf_types<64>::Elf_Addr,
- elfcpp::Elf_types<64>::Elf_Addr,
- unsigned int,
- unsigned int plt_offset,
- unsigned int plt_index)
- {
- memcpy(pov, plt_entry, plt_entry_size);
- elfcpp::Swap_unaligned<32, false>::writeval(pov + 1, plt_index);
- elfcpp::Swap<32, false>::writeval(pov + 7, -(plt_offset + 11));
- return 0;
- }
- void
- Output_data_plt_x86_64_bnd::fill_aplt_entry(
- unsigned char* pov,
- elfcpp::Elf_types<64>::Elf_Addr got_address,
- elfcpp::Elf_types<64>::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 + 7));
- 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 + 3, plt_got_pcrel_offset);
- }
- // The reserved TLSDESC entry in the PLT for an executable.
- const unsigned char
- Output_data_plt_x86_64_bnd::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)
- 0xf2, 0xff, 0x25, // jmpq *y(%rip)
- 0, 0, 0, 0, // replaced with offset of reserved TLSDESC_GOT entry
- 0x0f, 0x1f, 0 // nop
- };
- void
- Output_data_plt_x86_64_bnd::do_fill_tlsdesc_entry(
- unsigned char* pov,
- elfcpp::Elf_types<64>::Elf_Addr got_address,
- elfcpp::Elf_types<64>::Elf_Addr plt_address,
- elfcpp::Elf_types<64>::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 + 9,
- (got_base
- + tlsdesc_got_offset
- - (plt_address + plt_offset
- + 13)));
- }
- // 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<>
- const unsigned char
- Output_data_plt_x86_64_ibt<32>::first_plt_entry[plt_entry_size] =
- {
- // MPX isn't supported for x32, so we don't need the BND prefix.
- // 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<>
- const unsigned char
- Output_data_plt_x86_64_ibt<64>::first_plt_entry[plt_entry_size] =
- {
- // Use the BND prefix so that IBT is compatible with MPX.
- 0xff, 0x35, // pushq contents of memory address
- 0, 0, 0, 0, // replaced with address of .got + 8
- 0xf2, 0xff, 0x25, // bnd jmp indirect
- 0, 0, 0, 0, // replaced with address of .got + 16
- 0x0f, 0x1f, 0x00 // nop
- };
- 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 = (size == 32) ? 8 : 9;
- 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<>
- const unsigned char
- Output_data_plt_x86_64_ibt<32>::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
- };
- template<>
- const unsigned char
- Output_data_plt_x86_64_ibt<64>::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
- 0xf2, 0xe9, // bnd jmpq relative
- 0, 0, 0, 0, // replaced with offset to start of .plt
- 0x90 // nop
- };
- // Entries in the IBT Additional PLT.
- template<>
- const unsigned char
- Output_data_plt_x86_64_ibt<32>::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<>
- const unsigned char
- Output_data_plt_x86_64_ibt<64>::aplt_entry[aplt_entry_size] =
- {
- // From AMD64 ABI Draft 1.0-rc1, Chapter 13.
- 0xf3, 0x0f, 0x1e, 0xfa, // endbr64
- 0xf2, 0xff, 0x25, // bnd jmpq indirect
- 0, 0, 0, 0, // replaced with address of symbol in .got
- 0x0f, 0x1f, 0x04, 0x00, // nop
- 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 = (size == 32) ? 10 : 11;
- 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 = (size == 32) ? 6 : 7;
- // 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 BND PLT.
- const unsigned char
- Output_data_plt_x86_64_bnd::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_lit5, // Push 5.
- elfcpp::DW_OP_ge, // >= ((%rip & 0xf) >= 5)
- elfcpp::DW_OP_lit3, // Push 3.
- elfcpp::DW_OP_shl, // << (((%rip & 0xf) >= 5) << 3)
- elfcpp::DW_OP_plus, // + ((((%rip&0xf)>=5)<<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 BND 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 BND PLT.
- void
- Output_data_plt_x86_64_bnd::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);
- }
- // 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 if (parameters->options().bndplt())
- return new Output_data_plt_x86_64_bnd(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 if (parameters->options().bndplt())
- return new Output_data_plt_x86_64_bnd(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.
- template<int size>
- tls::Tls_optimization
- Target_x86_64<size>::optimize_tls_reloc(bool is_final, int r_type)
- {
- // 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_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_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.
- 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_PC32_BND:
- 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_PLT32_BND:
- 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_GOTPLT64:
- // Absolute in GOT.
- return Symbol::ABSOLUTE_REF;
- case elfcpp::R_X86_64_TLSGD: // Global-dynamic
- case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url)
- case elfcpp::R_X86_64_TLSDESC_CALL:
- case elfcpp::R_X86_64_TLSLD: // Local-dynamic
- case elfcpp::R_X86_64_DTPOFF32:
- case elfcpp::R_X86_64_DTPOFF64:
- case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
- case elfcpp::R_X86_64_TPOFF32: // Local-exec
- return Symbol::TLS_REF;
- case elfcpp::R_X86_64_COPY:
- case elfcpp::R_X86_64_GLOB_DAT:
- case elfcpp::R_X86_64_JUMP_SLOT:
- case elfcpp::R_X86_64_RELATIVE:
- case elfcpp::R_X86_64_IRELATIVE:
- case elfcpp::R_X86_64_TPOFF64:
- case elfcpp::R_X86_64_DTPMOD64:
- case elfcpp::R_X86_64_TLSDESC:
- case elfcpp::R_X86_64_SIZE32:
- case elfcpp::R_X86_64_SIZE64:
- default:
- // Not expected. We will give an error later.
- return 0;
- }
- }
- // Report an unsupported relocation against a local symbol.
- template<int size>
- void
- Target_x86_64<size>::Scan::unsupported_reloc_local(
- Sized_relobj_file<size, false>* object,
- unsigned int r_type)
- {
- gold_error(_("%s: unsupported reloc %u against local symbol"),
- object->name().c_str(), r_type);
- }
- // We are about to emit a dynamic relocation of type R_TYPE. If the
- // dynamic linker does not support it, issue an error. The GNU linker
- // only issues a non-PIC error for an allocated read-only section.
- // Here we know the section is allocated, but we don't know that it is
- // read-only. But we check for all the relocation types which the
- // glibc dynamic linker supports, so it seems appropriate to issue an
- // error even if the section is not read-only. If GSYM is not NULL,
- // it is the symbol the relocation is against; if it is NULL, the
- // relocation is against a local symbol.
- template<int size>
- void
- Target_x86_64<size>::Scan::check_non_pic(Relobj* object, unsigned int r_type,
- Symbol* gsym)
- {
- switch (r_type)
- {
- // These are the relocation types supported by glibc for x86_64
- // which should always work.
- case elfcpp::R_X86_64_RELATIVE:
- case elfcpp::R_X86_64_IRELATIVE:
- case elfcpp::R_X86_64_GLOB_DAT:
- case elfcpp::R_X86_64_JUMP_SLOT:
- case elfcpp::R_X86_64_DTPMOD64:
- case elfcpp::R_X86_64_DTPOFF64:
- case elfcpp::R_X86_64_TPOFF64:
- case elfcpp::R_X86_64_64:
- case elfcpp::R_X86_64_COPY:
- return;
- // glibc supports these reloc types, but they can overflow.
- case elfcpp::R_X86_64_PC32:
- case elfcpp::R_X86_64_PC32_BND:
- // A PC relative reference is OK against a local symbol or if
- // the symbol is defined locally.
- if (gsym == NULL
- || (!gsym->is_from_dynobj()
- && !gsym->is_undefined()
- && !gsym->is_preemptible()))
- return;
- // Fall through.
- case elfcpp::R_X86_64_32:
- // R_X86_64_32 is OK for x32.
- if (size == 32 && r_type == elfcpp::R_X86_64_32)
- return;
- if (this->issued_non_pic_error_)
- return;
- gold_assert(parameters->options().output_is_position_independent());
- if (gsym == NULL)
- object->error(_("requires dynamic R_X86_64_32 reloc which may "
- "overflow at runtime; recompile with -fPIC"));
- else
- {
- const char *r_name;
- switch (r_type)
- {
- case elfcpp::R_X86_64_32:
- r_name = "R_X86_64_32";
- break;
- case elfcpp::R_X86_64_PC32:
- r_name = "R_X86_64_PC32";
- break;
- case elfcpp::R_X86_64_PC32_BND:
- r_name = "R_X86_64_PC32_BND";
- break;
- default:
- gold_unreachable();
- break;
- }
- object->error(_("requires dynamic %s reloc against '%s' "
- "which may overflow at runtime; recompile "
- "with -fPIC"),
- r_name, gsym->name());
- }
- this->issued_non_pic_error_ = true;
- return;
- default:
- // This prevents us from issuing more than one error per reloc
- // section. But we can still wind up issuing more than one
- // error per object file.
- if (this->issued_non_pic_error_)
- return;
- gold_assert(parameters->options().output_is_position_independent());
- object->error(_("requires unsupported dynamic reloc %u; "
- "recompile with -fPIC"),
- r_type);
- this->issued_non_pic_error_ = true;
- return;
- case elfcpp::R_X86_64_NONE:
- gold_unreachable();
- }
- }
- // Return whether we need to make a PLT entry for a relocation of the
- // given type against a STT_GNU_IFUNC symbol.
- template<int size>
- bool
- Target_x86_64<size>::Scan::reloc_needs_plt_for_ifunc(
- Sized_relobj_file<size, false>* object,
- unsigned int r_type)
- {
- int flags = Scan::get_reference_flags(r_type);
- if (flags & Symbol::TLS_REF)
- gold_error(_("%s: unsupported TLS reloc %u for IFUNC symbol"),
- object->name().c_str(), r_type);
- return flags != 0;
- }
- // Scan a relocation for a local symbol.
- template<int size>
- inline void
- Target_x86_64<size>::Scan::local(Symbol_table* symtab,
- Layout* layout,
- Target_x86_64<size>* 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)
- {
- if (is_discarded)
- return;
- // A local STT_GNU_IFUNC symbol may require a PLT entry.
- bool is_ifunc = lsym.get_st_type() == elfcpp::STT_GNU_IFUNC;
- if (is_ifunc && this->reloc_needs_plt_for_ifunc(object, r_type))
- {
- unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info());
- target->make_local_ifunc_plt_entry(symtab, layout, object, r_sym);
- }
- switch (r_type)
- {
- case elfcpp::R_X86_64_NONE:
- case elfcpp::R_X86_64_GNU_VTINHERIT:
- case elfcpp::R_X86_64_GNU_VTENTRY:
- break;
- case elfcpp::R_X86_64_64:
- // If building a shared library (or a position-independent
- // executable), we need to create a dynamic relocation for this
- // location. The relocation applied at link time will apply the
- // link-time value, so we flag the location with an
- // R_X86_64_RELATIVE relocation so the dynamic loader can
- // relocate it easily.
- if (parameters->options().output_is_position_independent())
- {
- unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info());
- Reloc_section* rela_dyn = target->rela_dyn_section(layout);
- rela_dyn->add_local_relative(object, r_sym,
- (size == 32
- ? elfcpp::R_X86_64_RELATIVE64
- : elfcpp::R_X86_64_RELATIVE),
- output_section, data_shndx,
- reloc.get_r_offset(),
- reloc.get_r_addend(), is_ifunc);
- }
- break;
- case elfcpp::R_X86_64_32:
- case elfcpp::R_X86_64_32S:
- case elfcpp::R_X86_64_16:
- case elfcpp::R_X86_64_8:
- // If building a shared library (or a position-independent
- // executable), we need to create a dynamic relocation for this
- // location. We can't use an R_X86_64_RELATIVE relocation
- // because that is always a 64-bit relocation.
- if (parameters->options().output_is_position_independent())
- {
- // Use R_X86_64_RELATIVE relocation for R_X86_64_32 under x32.
- if (size == 32 && r_type == elfcpp::R_X86_64_32)
- {
- unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info());
- Reloc_section* rela_dyn = target->rela_dyn_section(layout);
- rela_dyn->add_local_relative(object, r_sym,
- elfcpp::R_X86_64_RELATIVE,
- output_section, data_shndx,
- reloc.get_r_offset(),
- reloc.get_r_addend(), is_ifunc);
- break;
- }
- this->check_non_pic(object, r_type, NULL);
- Reloc_section* rela_dyn = target->rela_dyn_section(layout);
- unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info());
- if (lsym.get_st_type() != elfcpp::STT_SECTION)
- rela_dyn->add_local(object, r_sym, r_type, output_section,
- data_shndx, reloc.get_r_offset(),
- reloc.get_r_addend());
- else
- {
- gold_assert(lsym.get_st_value() == 0);
- unsigned int shndx = lsym.get_st_shndx();
- bool is_ordinary;
- shndx = object->adjust_sym_shndx(r_sym, shndx,
- &is_ordinary);
- if (!is_ordinary)
- object->error(_("section symbol %u has bad shndx %u"),
- r_sym, shndx);
- else
- rela_dyn->add_local_section(object, shndx,
- r_type, output_section,
- data_shndx, reloc.get_r_offset(),
- reloc.get_r_addend());
- }
- }
- break;
- case elfcpp::R_X86_64_PC64:
- case elfcpp::R_X86_64_PC32:
- case elfcpp::R_X86_64_PC32_BND:
- case elfcpp::R_X86_64_PC16:
- case elfcpp::R_X86_64_PC8:
- break;
- case elfcpp::R_X86_64_PLT32:
- case elfcpp::R_X86_64_PLT32_BND:
- // Since we know this is a local symbol, we can handle this as a
- // PC32 reloc.
- break;
- case elfcpp::R_X86_64_GOTPC32:
- case elfcpp::R_X86_64_GOTOFF64:
- case elfcpp::R_X86_64_GOTPC64:
- case elfcpp::R_X86_64_PLTOFF64:
- // We need a GOT section.
- target->got_section(symtab, layout);
- // For PLTOFF64, we'd normally want a PLT section, but since we
- // know this is a local symbol, no PLT is needed.
- break;
- 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_GOTPLT64:
- {
- // The symbol requires a GOT section.
- Output_data_got<64, false>* got = target->got_section(symtab, layout);
- // If the relocation symbol isn't IFUNC,
- // and is local, then we will convert
- // mov foo@GOTPCREL(%rip), %reg
- // to lea foo(%rip), %reg.
- // in Relocate::relocate.
- if (!parameters->incremental()
- && (r_type == elfcpp::R_X86_64_GOTPCREL
- || r_type == elfcpp::R_X86_64_GOTPCRELX
- || r_type == elfcpp::R_X86_64_REX_GOTPCRELX)
- && reloc.get_r_addend() == -4
- && reloc.get_r_offset() >= 2
- && !is_ifunc)
- {
- section_size_type stype;
- const unsigned char* view = object->section_contents(data_shndx,
- &stype, true);
- if (view[reloc.get_r_offset() - 2] == 0x8b)
- break;
- }
- // The symbol requires a GOT entry.
- unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info());
- // For a STT_GNU_IFUNC symbol we want the PLT offset. That
- // lets function pointers compare correctly with shared
- // libraries. Otherwise we would need an IRELATIVE reloc.
- bool is_new;
- if (is_ifunc)
- is_new = got->add_local_plt(object, r_sym, GOT_TYPE_STANDARD);
- else
- is_new = got->add_local(object, r_sym, GOT_TYPE_STANDARD);
- if (is_new)
- {
- // If we are generating a shared object, we need to add a
- // dynamic relocation for this symbol's GOT entry.
- if (parameters->options().output_is_position_independent())
- {
- Reloc_section* rela_dyn = target->rela_dyn_section(layout);
- // R_X86_64_RELATIVE assumes a 64-bit relocation.
- if (r_type != elfcpp::R_X86_64_GOT32)
- {
- unsigned int got_offset =
- object->local_got_offset(r_sym, GOT_TYPE_STANDARD);
- rela_dyn->add_local_relative(object, r_sym,
- elfcpp::R_X86_64_RELATIVE,
- got, got_offset, 0, is_ifunc);
- }
- else
- {
- this->check_non_pic(object, r_type, NULL);
- gold_assert(lsym.get_st_type() != elfcpp::STT_SECTION);
- rela_dyn->add_local(
- object, r_sym, r_type, got,
- object->local_got_offset(r_sym, GOT_TYPE_STANDARD), 0);
- }
- }
- }
- // For GOTPLT64, we'd normally want a PLT section, but since
- // we know this is a local symbol, no PLT is needed.
- }
- break;
- case elfcpp::R_X86_64_COPY:
- case elfcpp::R_X86_64_GLOB_DAT:
- case elfcpp::R_X86_64_JUMP_SLOT:
- case elfcpp::R_X86_64_RELATIVE:
- case elfcpp::R_X86_64_IRELATIVE:
- // These are outstanding tls relocs, which are unexpected when linking
- case elfcpp::R_X86_64_TPOFF64:
- case elfcpp::R_X86_64_DTPMOD64:
- case elfcpp::R_X86_64_TLSDESC:
- gold_error(_("%s: unexpected reloc %u in object file"),
- object->name().c_str(), r_type);
- break;
- // These are initial tls relocs, which are expected when linking
- case elfcpp::R_X86_64_TLSGD: // Global-dynamic
- case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url)
- case elfcpp::R_X86_64_TLSDESC_CALL:
- case elfcpp::R_X86_64_TLSLD: // Local-dynamic
- case elfcpp::R_X86_64_DTPOFF32:
- case elfcpp::R_X86_64_DTPOFF64:
- case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
- case elfcpp::R_X86_64_TPOFF32: // Local-exec
- {
- bool output_is_shared = parameters->options().shared();
- const tls::Tls_optimization optimized_type
- = Target_x86_64<size>::optimize_tls_reloc(!output_is_shared,
- r_type);
- switch (r_type)
- {
- case elfcpp::R_X86_64_TLSGD: // General-dynamic
- if (optimized_type == tls::TLSOPT_NONE)
- {
- // Create a pair of GOT entries for the module index and
- // dtv-relative offset.
- Output_data_got<64, false>* got
- = target->got_section(symtab, layout);
- unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info());
- unsigned int shndx = lsym.get_st_shndx();
- bool is_ordinary;
- shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary);
- if (!is_ordinary)
- object->error(_("local symbol %u has bad shndx %u"),
- r_sym, shndx);
- else
- got->add_local_pair_with_rel(object, r_sym,
- shndx,
- GOT_TYPE_TLS_PAIR,
- target->rela_dyn_section(layout),
- elfcpp::R_X86_64_DTPMOD64);
- }
- else if (optimized_type != tls::TLSOPT_TO_LE)
- unsupported_reloc_local(object, r_type);
- break;
- case elfcpp::R_X86_64_GOTPC32_TLSDESC:
- target->define_tls_base_symbol(symtab, layout);
- if (optimized_type == tls::TLSOPT_NONE)
- {
- // Create reserved PLT and GOT entries for the resolver.
- target->reserve_tlsdesc_entries(symtab, layout);
- // Generate a double GOT entry with an
- // R_X86_64_TLSDESC reloc. The R_X86_64_TLSDESC reloc
- // is resolved lazily, so the GOT entry needs to be in
- // an area in .got.plt, not .got. Call got_section to
- // make sure the section has been created.
- target->got_section(symtab, layout);
- Output_data_got<64, false>* got = target->got_tlsdesc_section();
- unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info());
- if (!object->local_has_got_offset(r_sym, GOT_TYPE_TLS_DESC))
- {
- unsigned int got_offset = got->add_constant(0);
- got->add_constant(0);
- object->set_local_got_offset(r_sym, GOT_TYPE_TLS_DESC,
- got_offset);
- Reloc_section* rt = target->rela_tlsdesc_section(layout);
- // We store the arguments we need in a vector, and
- // use the index into the vector as the parameter
- // to pass to the target specific routines.
- uintptr_t intarg = target->add_tlsdesc_info(object, r_sym);
- void* arg = reinterpret_cast<void*>(intarg);
- rt->add_target_specific(elfcpp::R_X86_64_TLSDESC, arg,
- got, got_offset, 0);
- }
- }
- else if (optimized_type != tls::TLSOPT_TO_LE)
- unsupported_reloc_local(object, r_type);
- break;
- case elfcpp::R_X86_64_TLSDESC_CALL:
- break;
- case elfcpp::R_X86_64_TLSLD: // Local-dynamic
- if (optimized_type == tls::TLSOPT_NONE)
- {
- // Create a GOT entry for the module index.
- target->got_mod_index_entry(symtab, layout, object);
- }
- else if (optimized_type != tls::TLSOPT_TO_LE)
- unsupported_reloc_local(object, r_type);
- break;
- case elfcpp::R_X86_64_DTPOFF32:
- case elfcpp::R_X86_64_DTPOFF64:
- break;
- case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
- layout->set_has_static_tls();
- if (optimized_type == tls::TLSOPT_NONE)
- {
- // Create a GOT entry for the tp-relative offset.
- Output_data_got<64, false>* got
- = target->got_section(symtab, layout);
- unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info());
- got->add_local_with_rel(object, r_sym, GOT_TYPE_TLS_OFFSET,
- target->rela_dyn_section(layout),
- elfcpp::R_X86_64_TPOFF64);
- }
- else if (optimized_type != tls::TLSOPT_TO_LE)
- unsupported_reloc_local(object, r_type);
- break;
- case elfcpp::R_X86_64_TPOFF32: // Local-exec
- layout->set_has_static_tls();
- if (output_is_shared)
- unsupported_reloc_local(object, r_type);
- break;
- default:
- gold_unreachable();
- }
- }
- break;
- case elfcpp::R_X86_64_SIZE32:
- case elfcpp::R_X86_64_SIZE64:
- default:
- gold_error(_("%s: unsupported reloc %u against local symbol"),
- object->name().c_str(), r_type);
- break;
- }
- }
- // Report an unsupported relocation against a global symbol.
- template<int size>
- void
- Target_x86_64<size>::Scan::unsupported_reloc_global(
- Sized_relobj_file<size, false>* object,
- unsigned int r_type,
- Symbol* gsym)
- {
- gold_error(_("%s: unsupported reloc %u against global symbol %s"),
- object->name().c_str(), r_type, gsym->demangled_name().c_str());
- }
- // Returns true if this relocation type could be that of a function pointer.
- template<int size>
- inline bool
- Target_x86_64<size>::Scan::possible_function_pointer_reloc(
- Sized_relobj_file<size, false>* src_obj,
- unsigned int src_indx,
- unsigned int r_offset,
- unsigned int r_type)
- {
- switch (r_type)
- {
- 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:
- 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_GOTPLT64:
- {
- return true;
- }
- case elfcpp::R_X86_64_PC32:
- {
- // This relocation may be used both for function calls and
- // for taking address of a function. We distinguish between
- // them by checking the opcodes.
- uint64_t sh_flags = src_obj->section_flags(src_indx);
- bool is_executable = (sh_flags & elfcpp::SHF_EXECINSTR) != 0;
- if (is_executable)
- {
- section_size_type stype;
- const unsigned char* view = src_obj->section_contents(src_indx,
- &stype,
- true);
- // call
- if (r_offset >= 1
- && view[r_offset - 1] == 0xe8)
- return false;
- // jmp
- if (r_offset >= 1
- && view[r_offset - 1] == 0xe9)
- return false;
- // jo/jno/jb/jnb/je/jne/jna/ja/js/jns/jp/jnp/jl/jge/jle/jg
- if (r_offset >= 2
- && view[r_offset - 2] == 0x0f
- && view[r_offset - 1] >= 0x80
- && view[r_offset - 1] <= 0x8f)
- return false;
- }
- // Be conservative and treat all others as function pointers.
- return true;
- }
- }
- return false;
- }
- // For safe ICF, scan a relocation for a local symbol to check if it
- // corresponds to a function pointer being taken. In that case mark
- // the function whose pointer was taken as not foldable.
- template<int size>
- inline bool
- Target_x86_64<size>::Scan::local_reloc_may_be_function_pointer(
- Symbol_table* ,
- Layout* ,
- Target_x86_64<size>* ,
- Sized_relobj_file<size, false>* src_obj,
- unsigned int src_indx,
- Output_section* ,
- const elfcpp::Rela<size, false>& reloc,
- unsigned int r_type,
- const elfcpp::Sym<size, false>&)
- {
- return possible_function_pointer_reloc(src_obj, src_indx,
- reloc.get_r_offset(), r_type);
- }
- // For safe ICF, scan a relocation for a global symbol to check if it
- // corresponds to a function pointer being taken. In that case mark
- // the function whose pointer was taken as not foldable.
- template<int size>
- inline bool
- Target_x86_64<size>::Scan::global_reloc_may_be_function_pointer(
- Symbol_table*,
- Layout* ,
- Target_x86_64<size>* ,
- Sized_relobj_file<size, false>* src_obj,
- unsigned int src_indx,
- Output_section* ,
- const elfcpp::Rela<size, false>& reloc,
- unsigned int r_type,
- Symbol*)
- {
- return possible_function_pointer_reloc(src_obj, src_indx,
- reloc.get_r_offset(), r_type);
- }
- // Scan a relocation for a global symbol.
- template<int size>
- inline void
- Target_x86_64<size>::Scan::global(Symbol_table* symtab,
- Layout* layout,
- Target_x86_64<size>* 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)
- {
- // A STT_GNU_IFUNC symbol may require a PLT entry.
- if (gsym->type() == elfcpp::STT_GNU_IFUNC
- && this->reloc_needs_plt_for_ifunc(object, r_type))
- target->make_plt_entry(symtab, layout, gsym);
- switch (r_type)
- {
- case elfcpp::R_X86_64_NONE:
- case elfcpp::R_X86_64_GNU_VTINHERIT:
- case elfcpp::R_X86_64_GNU_VTENTRY:
- break;
- 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:
- {
- // Make a PLT entry if necessary.
- if (gsym->needs_plt_entry())
- {
- target->make_plt_entry(symtab, layout, gsym);
- // Since this is not a PC-relative relocation, we may be
- // taking the address of a function. In that case we need to
- // set the entry in the dynamic symbol table to the address of
- // the PLT entry.
- if (gsym->is_from_dynobj() && !parameters->options().shared())
- gsym->set_needs_dynsym_value();
- }
- // Make a dynamic relocation if necessary.
- if (gsym->needs_dynamic_reloc(Scan::get_reference_flags(r_type)))
- {
- if (!parameters->options().output_is_position_independent()
- && gsym->may_need_copy_reloc())
- {
- target->copy_reloc(symtab, layout, object,
- data_shndx, output_section, gsym, reloc);
- }
- else if (((size == 64 && r_type == elfcpp::R_X86_64_64)
- || (size == 32 && r_type == elfcpp::R_X86_64_32))
- && gsym->type() == elfcpp::STT_GNU_IFUNC
- && gsym->can_use_relative_reloc(false)
- && !gsym->is_from_dynobj()
- && !gsym->is_undefined()
- && !gsym->is_preemptible())
- {
- // Use an IRELATIVE reloc for a locally defined
- // STT_GNU_IFUNC symbol. This makes a function
- // address in a PIE executable match the address in a
- // shared library that it links against.
- Reloc_section* rela_dyn =
- target->rela_irelative_section(layout);
- unsigned int r_type = elfcpp::R_X86_64_IRELATIVE;
- rela_dyn->add_symbolless_global_addend(gsym, r_type,
- output_section, object,
- data_shndx,
- reloc.get_r_offset(),
- reloc.get_r_addend());
- }
- else if (((size == 64 && r_type == elfcpp::R_X86_64_64)
- || (size == 32 && r_type == elfcpp::R_X86_64_32))
- && gsym->can_use_relative_reloc(false))
- {
- Reloc_section* rela_dyn = target->rela_dyn_section(layout);
- rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_RELATIVE,
- output_section, object,
- data_shndx,
- reloc.get_r_offset(),
- reloc.get_r_addend(), false);
- }
- else
- {
- this->check_non_pic(object, r_type, gsym);
- Reloc_section* rela_dyn = target->rela_dyn_section(layout);
- rela_dyn->add_global(gsym, r_type, output_section, object,
- data_shndx, reloc.get_r_offset(),
- reloc.get_r_addend());
- }
- }
- }
- break;
- case elfcpp::R_X86_64_PC64:
- case elfcpp::R_X86_64_PC32:
- case elfcpp::R_X86_64_PC32_BND:
- case elfcpp::R_X86_64_PC16:
- case elfcpp::R_X86_64_PC8:
- {
- // Make a PLT entry if necessary.
- if (gsym->needs_plt_entry())
- target->make_plt_entry(symtab, layout, gsym);
- // Make a dynamic relocation if necessary.
- if (gsym->needs_dynamic_reloc(Scan::get_reference_flags(r_type)))
- {
- if (parameters->options().output_is_executable()
- && gsym->may_need_copy_reloc())
- {
- target->copy_reloc(symtab, layout, object,
- data_shndx, output_section, gsym, reloc);
- }
- else
- {
- this->check_non_pic(object, r_type, gsym);
- Reloc_section* rela_dyn = target->rela_dyn_section(layout);
- rela_dyn->add_global(gsym, r_type, output_section, object,
- data_shndx, reloc.get_r_offset(),
- reloc.get_r_addend());
- }
- }
- }
- break;
- 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_GOTPLT64:
- {
- // The symbol requires a GOT entry.
- Output_data_got<64, false>* got = target->got_section(symtab, layout);
- // If we convert this from
- // mov foo@GOTPCREL(%rip), %reg
- // to lea foo(%rip), %reg.
- // OR
- // if we convert
- // (callq|jmpq) *foo@GOTPCRELX(%rip) to
- // (callq|jmpq) foo
- // in Relocate::relocate, then there is nothing to do here.
- // We cannot make these optimizations in incremental linking mode,
- // because we look at the opcode to decide whether or not to make
- // change, and during an incremental update, the change may have
- // already been applied.
- Lazy_view<size> view(object, data_shndx);
- size_t r_offset = reloc.get_r_offset();
- if (!parameters->incremental()
- && reloc.get_r_addend() == -4
- && r_offset >= 2
- && Target_x86_64<size>::can_convert_mov_to_lea(gsym, r_type,
- r_offset, &view))
- break;
- if (!parameters->incremental()
- && r_offset >= 2
- && Target_x86_64<size>::can_convert_callq_to_direct(gsym, r_type,
- r_offset,
- &view))
- break;
- if (gsym->final_value_is_known())
- {
- // For a STT_GNU_IFUNC symbol we want the PLT address.
- if (gsym->type() == elfcpp::STT_GNU_IFUNC)
- got->add_global_plt(gsym, GOT_TYPE_STANDARD);
- else
- got->add_global(gsym, GOT_TYPE_STANDARD);
- }
- else
- {
- // If this symbol is not fully resolved, we need to add a
- // dynamic relocation for it.
- Reloc_section* rela_dyn = target->rela_dyn_section(layout);
- // Use a GLOB_DAT rather than a RELATIVE reloc if:
- //
- // 1) The symbol may be defined in some other module.
- //
- // 2) We are building a shared library and this is a
- // protected symbol; using GLOB_DAT means that the dynamic
- // linker can use the address of the PLT in the main
- // executable when appropriate so that function address
- // comparisons work.
- //
- // 3) This is a STT_GNU_IFUNC symbol in position dependent
- // code, again so that function address comparisons work.
- if (gsym->is_from_dynobj()
- || gsym->is_undefined()
- || gsym->is_preemptible()
- || (gsym->visibility() == elfcpp::STV_PROTECTED
- && parameters->options().shared())
- || (gsym->type() == elfcpp::STT_GNU_IFUNC
- && parameters->options().output_is_position_independent()))
- got->add_global_with_rel(gsym, GOT_TYPE_STANDARD, rela_dyn,
- elfcpp::R_X86_64_GLOB_DAT);
- else
- {
- // For a STT_GNU_IFUNC symbol we want to write the PLT
- // offset into the GOT, so that function pointer
- // comparisons work correctly.
- bool is_new;
- if (gsym->type() != elfcpp::STT_GNU_IFUNC)
- is_new = got->add_global(gsym, GOT_TYPE_STANDARD);
- else
- {
- is_new = got->add_global_plt(gsym, GOT_TYPE_STANDARD);
- // Tell the dynamic linker to use the PLT address
- // when resolving relocations.
- if (gsym->is_from_dynobj()
- && !parameters->options().shared())
- gsym->set_needs_dynsym_value();
- }
- if (is_new)
- {
- unsigned int got_off = gsym->got_offset(GOT_TYPE_STANDARD);
- rela_dyn->add_global_relative(gsym,
- elfcpp::R_X86_64_RELATIVE,
- got, got_off, 0, false);
- }
- }
- }
- }
- break;
- case elfcpp::R_X86_64_PLT32:
- case elfcpp::R_X86_64_PLT32_BND:
- // If the symbol is fully resolved, this is just a PC32 reloc.
- // Otherwise we need a PLT entry.
- if (gsym->final_value_is_known())
- break;
- // If building a shared library, we can also skip the PLT entry
- // if the symbol is defined in the output file and is protected
- // or hidden.
- if (gsym->is_defined()
- && !gsym->is_from_dynobj()
- && !gsym->is_preemptible())
- break;
- target->make_plt_entry(symtab, layout, gsym);
- break;
- case elfcpp::R_X86_64_GOTPC32:
- case elfcpp::R_X86_64_GOTOFF64:
- case elfcpp::R_X86_64_GOTPC64:
- case elfcpp::R_X86_64_PLTOFF64:
- // We need a GOT section.
- target->got_section(symtab, layout);
- // For PLTOFF64, we also need a PLT entry (but only if the
- // symbol is not fully resolved).
- if (r_type == elfcpp::R_X86_64_PLTOFF64
- && !gsym->final_value_is_known())
- target->make_plt_entry(symtab, layout, gsym);
- break;
- case elfcpp::R_X86_64_COPY:
- case elfcpp::R_X86_64_GLOB_DAT:
- case elfcpp::R_X86_64_JUMP_SLOT:
- case elfcpp::R_X86_64_RELATIVE:
- case elfcpp::R_X86_64_IRELATIVE:
- // These are outstanding tls relocs, which are unexpected when linking
- case elfcpp::R_X86_64_TPOFF64:
- case elfcpp::R_X86_64_DTPMOD64:
- case elfcpp::R_X86_64_TLSDESC:
- gold_error(_("%s: unexpected reloc %u in object file"),
- object->name().c_str(), r_type);
- break;
- // These are initial tls relocs, which are expected for global()
- case elfcpp::R_X86_64_TLSGD: // Global-dynamic
- case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url)
- case elfcpp::R_X86_64_TLSDESC_CALL:
- case elfcpp::R_X86_64_TLSLD: // Local-dynamic
- case elfcpp::R_X86_64_DTPOFF32:
- case elfcpp::R_X86_64_DTPOFF64:
- case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
- case elfcpp::R_X86_64_TPOFF32: // Local-exec
- {
- // For the Initial-Exec model, we can treat undef symbols as final
- // when building an executable.
- const bool is_final = (gsym->final_value_is_known() ||
- (r_type == elfcpp::R_X86_64_GOTTPOFF &&
- gsym->is_undefined() &&
- parameters->options().output_is_executable()));
- const tls::Tls_optimization optimized_type
- = Target_x86_64<size>::optimize_tls_reloc(is_final, r_type);
- switch (r_type)
- {
- case elfcpp::R_X86_64_TLSGD: // General-dynamic
- if (optimized_type == tls::TLSOPT_NONE)
- {
- // Create a pair of GOT entries for the module index and
- // dtv-relative offset.
- Output_data_got<64, false>* got
- = target->got_section(symtab, layout);
- got->add_global_pair_with_rel(gsym, GOT_TYPE_TLS_PAIR,
- target->rela_dyn_section(layout),
- elfcpp::R_X86_64_DTPMOD64,
- elfcpp::R_X86_64_DTPOFF64);
- }
- else if (optimized_type == tls::TLSOPT_TO_IE)
- {
- // Create a GOT entry for the tp-relative offset.
- Output_data_got<64, false>* got
- = target->got_section(symtab, layout);
- got->add_global_with_rel(gsym, GOT_TYPE_TLS_OFFSET,
- target->rela_dyn_section(layout),
- elfcpp::R_X86_64_TPOFF64);
- }
- else if (optimized_type != tls::TLSOPT_TO_LE)
- unsupported_reloc_global(object, r_type, gsym);
- break;
- case elfcpp::R_X86_64_GOTPC32_TLSDESC:
- target->define_tls_base_symbol(symtab, layout);
- if (optimized_type == tls::TLSOPT_NONE)
- {
- // Create reserved PLT and GOT entries for the resolver.
- target->reserve_tlsdesc_entries(symtab, layout);
- // Create a double GOT entry with an R_X86_64_TLSDESC
- // reloc. The R_X86_64_TLSDESC reloc is resolved
- // lazily, so the GOT entry needs to be in an area in
- // .got.plt, not .got. Call got_section to make sure
- // the section has been created.
- target->got_section(symtab, layout);
- Output_data_got<64, false>* got = target->got_tlsdesc_section();
- Reloc_section* rt = target->rela_tlsdesc_section(layout);
- got->add_global_pair_with_rel(gsym, GOT_TYPE_TLS_DESC, rt,
- elfcpp::R_X86_64_TLSDESC, 0);
- }
- else if (optimized_type == tls::TLSOPT_TO_IE)
- {
- // Create a GOT entry for the tp-relative offset.
- Output_data_got<64, false>* got
- = target->got_section(symtab, layout);
- got->add_global_with_rel(gsym, GOT_TYPE_TLS_OFFSET,
- target->rela_dyn_section(layout),
- elfcpp::R_X86_64_TPOFF64);
- }
- else if (optimized_type != tls::TLSOPT_TO_LE)
- unsupported_reloc_global(object, r_type, gsym);
- break;
- case elfcpp::R_X86_64_TLSDESC_CALL:
- break;
- case elfcpp::R_X86_64_TLSLD: // Local-dynamic
- if (optimized_type == tls::TLSOPT_NONE)
- {
- // Create a GOT entry for the module index.
- target->got_mod_index_entry(symtab, layout, object);
- }
- else if (optimized_type != tls::TLSOPT_TO_LE)
- unsupported_reloc_global(object, r_type, gsym);
- break;
- case elfcpp::R_X86_64_DTPOFF32:
- case elfcpp::R_X86_64_DTPOFF64:
- break;
- case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
- layout->set_has_static_tls();
- if (optimized_type == tls::TLSOPT_NONE)
- {
- // Create a GOT entry for the tp-relative offset.
- Output_data_got<64, false>* got
- = target->got_section(symtab, layout);
- got->add_global_with_rel(gsym, GOT_TYPE_TLS_OFFSET,
- target->rela_dyn_section(layout),
- elfcpp::R_X86_64_TPOFF64);
- }
- else if (optimized_type != tls::TLSOPT_TO_LE)
- unsupported_reloc_global(object, r_type, gsym);
- break;
- case elfcpp::R_X86_64_TPOFF32: // Local-exec
- layout->set_has_static_tls();
- if (parameters->options().shared())
- unsupported_reloc_global(object, r_type, gsym);
- break;
- default:
- gold_unreachable();
- }
- }
- break;
- case elfcpp::R_X86_64_SIZE32:
- case elfcpp::R_X86_64_SIZE64:
- default:
- gold_error(_("%s: unsupported reloc %u against global symbol %s"),
- object->name().c_str(), r_type,
- gsym->demangled_name().c_str());
- break;
- }
- }
- template<int size>
- void
- Target_x86_64<size>::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)
- {
- typedef gold::Default_classify_reloc<elfcpp::SHT_RELA, size, false>
- Classify_reloc;
- if (sh_type == elfcpp::SHT_REL)
- {
- return;
- }
- gold::gc_process_relocs<size, false, Target_x86_64<size>, Scan,
- Classify_reloc>(
- symtab,
- layout,
- this,
- object,
- data_shndx,
- prelocs,
- reloc_count,
- output_section,
- needs_special_offset_handling,
- local_symbol_count,
- plocal_symbols);
- }
- // Scan relocations for a section.
- template<int size>
- void
- Target_x86_64<size>::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)
- {
- typedef gold::Default_classify_reloc<elfcpp::SHT_RELA, size, false>
- Classify_reloc;
- if (sh_type == elfcpp::SHT_REL)
- {
- gold_error(_("%s: unsupported REL reloc section"),
- object->name().c_str());
- return;
- }
- gold::scan_relocs<size, false, Target_x86_64<size>, Scan, Classify_reloc>(
- symtab,
- layout,
- this,
- object,
- data_shndx,
- prelocs,
- reloc_count,
- output_section,
- needs_special_offset_handling,
- local_symbol_count,
- plocal_symbols);
- }
- // Finalize the sections.
- template<int size>
- void
- Target_x86_64<size>::do_finalize_sections(
- Layout* layout,
- const Input_objects*,
- Symbol_table* symtab)
- {
- const Reloc_section* rel_plt = (this->plt_ == NULL
- ? NULL
- : this->plt_->rela_plt());
- layout->add_target_dynamic_tags(false, this->got_plt_, rel_plt,
- this->rela_dyn_, true, false);
- // Fill in some more dynamic tags.
- Output_data_dynamic* const odyn = layout->dynamic_data();
- if (odyn != NULL)
- {
- if (this->plt_ != NULL
- && this->plt_->output_section() != NULL
- && this->plt_->has_tlsdesc_entry())
- {
- unsigned int plt_offset = this->plt_->get_tlsdesc_plt_offset();
- unsigned int got_offset = this->plt_->get_tlsdesc_got_offset();
- this->got_->finalize_data_size();
- odyn->add_section_plus_offset(elfcpp::DT_TLSDESC_PLT,
- this->plt_, plt_offset);
- odyn->add_section_plus_offset(elfcpp::DT_TLSDESC_GOT,
- this->got_, got_offset);
- }
- }
- // Emit any relocs we saved in an attempt to avoid generating COPY
- // relocs.
- if (this->copy_relocs_.any_saved_relocs())
- this->copy_relocs_.emit(this->rela_dyn_section(layout));
- // Set the size of the _GLOBAL_OFFSET_TABLE_ symbol to the size of
- // the .got.plt section.
- Symbol* sym = this->global_offset_table_;
- if (sym != NULL)
- {
- uint64_t data_size = this->got_plt_->current_data_size();
- symtab->get_sized_symbol<size>(sym)->set_symsize(data_size);
- }
- if (parameters->doing_static_link()
- && (this->plt_ == NULL || !this->plt_->has_irelative_section()))
- {
- // If linking statically, make sure that the __rela_iplt symbols
- // were defined if necessary, even if we didn't create a PLT.
- static const Define_symbol_in_segment syms[] =
- {
- {
- "__rela_iplt_start", // name
- elfcpp::PT_LOAD, // segment_type
- elfcpp::PF_W, // segment_flags_set
- elfcpp::PF(0), // segment_flags_clear
- 0, // value
- 0, // size
- elfcpp::STT_NOTYPE, // type
- elfcpp::STB_GLOBAL, // binding
- elfcpp::STV_HIDDEN, // visibility
- 0, // nonvis
- Symbol::SEGMENT_START, // offset_from_base
- true // only_if_ref
- },
- {
- "__rela_iplt_end", // name
- elfcpp::PT_LOAD, // segment_type
- elfcpp::PF_W, // segment_flags_set
- elfcpp::PF(0), // segment_flags_clear
- 0, // value
- 0, // size
- elfcpp::STT_NOTYPE, // type
- elfcpp::STB_GLOBAL, // binding
- elfcpp::STV_HIDDEN, // visibility
- 0, // nonvis
- Symbol::SEGMENT_START, // offset_from_base
- true // only_if_ref
- }
- };
- symtab->define_symbols(layout, 2, syms,
- layout->script_options()->saw_sections_clause());
- }
- }
- // For x32, we need to handle PC-relative relocations using full 64-bit
- // arithmetic, so that we can detect relocation overflows properly.
- // This class overrides the pcrela32_check methods from the defaults in
- // Relocate_functions in reloc.h.
- template<int size>
- class X86_64_relocate_functions : public Relocate_functions<size, false>
- {
- public:
- typedef Relocate_functions<size, false> Base;
- // Do a simple PC relative relocation with the addend in the
- // relocation.
- static inline typename Base::Reloc_status
- pcrela32_check(unsigned char* view,
- typename elfcpp::Elf_types<64>::Elf_Addr value,
- typename elfcpp::Elf_types<64>::Elf_Swxword addend,
- typename elfcpp::Elf_types<64>::Elf_Addr address)
- {
- typedef typename elfcpp::Swap<32, false>::Valtype Valtype;
- Valtype* wv = reinterpret_cast<Valtype*>(view);
- value = value + addend - address;
- elfcpp::Swap<32, false>::writeval(wv, value);
- return (Bits<32>::has_overflow(value)
- ? Base::RELOC_OVERFLOW : Base::RELOC_OK);
- }
- // Do a simple PC relative relocation with a Symbol_value with the
- // addend in the relocation.
- static inline typename Base::Reloc_status
- pcrela32_check(unsigned char* view,
- const Sized_relobj_file<size, false>* object,
- const Symbol_value<size>* psymval,
- typename elfcpp::Elf_types<64>::Elf_Swxword addend,
- typename elfcpp::Elf_types<64>::Elf_Addr address)
- {
- typedef typename elfcpp::Swap<32, false>::Valtype Valtype;
- Valtype* wv = reinterpret_cast<Valtype*>(view);
- typename elfcpp::Elf_types<64>::Elf_Addr value;
- if (addend >= 0)
- value = psymval->value(object, addend);
- else
- {
- // For negative addends, get the symbol value without
- // the addend, then add the addend using 64-bit arithmetic.
- value = psymval->value(object, 0);
- value += addend;
- }
- value -= address;
- elfcpp::Swap<32, false>::writeval(wv, value);
- return (Bits<32>::has_overflow(value)
- ? Base::RELOC_OVERFLOW : Base::RELOC_OK);
- }
- };
- // Perform a relocation.
- template<int size>
- inline bool
- Target_x86_64<size>::Relocate::relocate(
- const Relocate_info<size, false>* relinfo,
- unsigned int,
- Target_x86_64<size>* target,
- Output_section*,
- size_t relnum,
- const unsigned char* preloc,
- const Sized_symbol<size>* gsym,
- const Symbol_value<size>* psymval,
- unsigned char* view,
- typename elfcpp::Elf_types<size>::Elf_Addr address,
- section_size_type view_size)
- {
- typedef X86_64_relocate_functions<size> Reloc_funcs;
- const elfcpp::Rela<size, false> rela(preloc);
- unsigned int r_type = elfcpp::elf_r_type<size>(rela.get_r_info());
- if (this->skip_call_tls_get_addr_)
- {
- if ((r_type != elfcpp::R_X86_64_PLT32
- && r_type != elfcpp::R_X86_64_GOTPCREL
- && r_type != elfcpp::R_X86_64_GOTPCRELX
- && r_type != elfcpp::R_X86_64_PLT32_BND
- && r_type != elfcpp::R_X86_64_PC32_BND
- && r_type != elfcpp::R_X86_64_PC32)
- || gsym == NULL
- || strcmp(gsym->name(), "__tls_get_addr") != 0)
- {
- gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
- _("missing expected TLS relocation"));
- this->skip_call_tls_get_addr_ = false;
- }
- else
- {
- this->skip_call_tls_get_addr_ = false;
- return false;
- }
- }
- if (view == NULL)
- return true;
- const Sized_relobj_file<size, false>* object = relinfo->object;
- // Pick the value to use for symbols defined in the PLT.
- Symbol_value<size> symval;
- if (gsym != NULL
- && gsym->use_plt_offset(Scan::get_reference_flags(r_type)))
- {
- symval.set_output_value(target->plt_address_for_global(gsym));
- psymval = &symval;
- }
- else if (gsym == NULL && psymval->is_ifunc_symbol())
- {
- unsigned int r_sym = elfcpp::elf_r_sym<size>(rela.get_r_info());
- if (object->local_has_plt_offset(r_sym))
- {
- symval.set_output_value(target->plt_address_for_local(object, r_sym));
- psymval = &symval;
- }
- }
- const elfcpp::Elf_Xword addend = rela.get_r_addend();
- // Get the GOT offset if needed.
- // The GOT pointer points to the end of the GOT section.
- // We need to subtract the size of the GOT section to get
- // the actual offset to use in the relocation.
- bool have_got_offset = false;
- // Since the actual offset is always negative, we use signed int to
- // support 64-bit GOT relocations.
- int got_offset = 0;
- switch (r_type)
- {
- case elfcpp::R_X86_64_GOT32:
- case elfcpp::R_X86_64_GOT64:
- case elfcpp::R_X86_64_GOTPLT64:
- case elfcpp::R_X86_64_GOTPCREL64:
- if (gsym != NULL)
- {
- gold_assert(gsym->has_got_offset(GOT_TYPE_STANDARD));
- got_offset = gsym->got_offset(GOT_TYPE_STANDARD) - target->got_size();
- }
- else
- {
- unsigned int r_sym = elfcpp::elf_r_sym<size>(rela.get_r_info());
- gold_assert(object->local_has_got_offset(r_sym, GOT_TYPE_STANDARD));
- got_offset = (object->local_got_offset(r_sym, GOT_TYPE_STANDARD)
- - target->got_size());
- }
- have_got_offset = true;
- break;
- default:
- break;
- }
- typename Reloc_funcs::Reloc_status rstatus = Reloc_funcs::RELOC_OK;
- switch (r_type)
- {
- case elfcpp::R_X86_64_NONE:
- case elfcpp::R_X86_64_GNU_VTINHERIT:
- case elfcpp::R_X86_64_GNU_VTENTRY:
- break;
- case elfcpp::R_X86_64_64:
- Reloc_funcs::rela64(view, object, psymval, addend);
- break;
- case elfcpp::R_X86_64_PC64:
- Reloc_funcs::pcrela64(view, object, psymval, addend,
- address);
- break;
- case elfcpp::R_X86_64_32:
- rstatus = Reloc_funcs::rela32_check(view, object, psymval, addend,
- Reloc_funcs::CHECK_UNSIGNED);
- break;
- case elfcpp::R_X86_64_32S:
- rstatus = Reloc_funcs::rela32_check(view, object, psymval, addend,
- Reloc_funcs::CHECK_SIGNED);
- break;
- case elfcpp::R_X86_64_PC32:
- case elfcpp::R_X86_64_PC32_BND:
- rstatus = Reloc_funcs::pcrela32_check(view, object, psymval, addend,
- address);
- break;
- case elfcpp::R_X86_64_16:
- Reloc_funcs::rela16(view, object, psymval, addend);
- break;
- case elfcpp::R_X86_64_PC16:
- Reloc_funcs::pcrela16(view, object, psymval, addend, address);
- break;
- case elfcpp::R_X86_64_8:
- Reloc_funcs::rela8(view, object, psymval, addend);
- break;
- case elfcpp::R_X86_64_PC8:
- Reloc_funcs::pcrela8(view, object, psymval, addend, address);
- break;
- case elfcpp::R_X86_64_PLT32:
- case elfcpp::R_X86_64_PLT32_BND:
- gold_assert(gsym == NULL
- || gsym->has_plt_offset()
- || gsym->final_value_is_known()
- || (gsym->is_defined()
- && !gsym->is_from_dynobj()
- && !gsym->is_preemptible()));
- // Note: while this code looks the same as for R_X86_64_PC32, it
- // behaves differently because psymval was set to point to
- // the PLT entry, rather than the symbol, in Scan::global().
- rstatus = Reloc_funcs::pcrela32_check(view, object, psymval, addend,
- address);
- break;
- case elfcpp::R_X86_64_PLTOFF64:
- {
- gold_assert(gsym);
- gold_assert(gsym->has_plt_offset()
- || gsym->final_value_is_known());
- typename elfcpp::Elf_types<size>::Elf_Addr got_address;
- // This is the address of GLOBAL_OFFSET_TABLE.
- got_address = target->got_plt_section()->address();
- Reloc_funcs::rela64(view, object, psymval, addend - got_address);
- }
- break;
- case elfcpp::R_X86_64_GOT32:
- gold_assert(have_got_offset);
- Reloc_funcs::rela32(view, got_offset, addend);
- break;
- case elfcpp::R_X86_64_GOTPC32:
- {
- gold_assert(gsym);
- typename elfcpp::Elf_types<size>::Elf_Addr value;
- value = target->got_plt_section()->address();
- Reloc_funcs::pcrela32_check(view, value, addend, address);
- }
- break;
- case elfcpp::R_X86_64_GOT64:
- case elfcpp::R_X86_64_GOTPLT64:
- // R_X86_64_GOTPLT64 is obsolete and treated the same as
- // GOT64.
- gold_assert(have_got_offset);
- Reloc_funcs::rela64(view, got_offset, addend);
- break;
- case elfcpp::R_X86_64_GOTPC64:
- {
- gold_assert(gsym);
- typename elfcpp::Elf_types<size>::Elf_Addr value;
- value = target->got_plt_section()->address();
- Reloc_funcs::pcrela64(view, value, addend, address);
- }
- break;
- case elfcpp::R_X86_64_GOTOFF64:
- {
- typename elfcpp::Elf_types<size>::Elf_Addr reladdr;
- reladdr = target->got_plt_section()->address();
- Reloc_funcs::pcrela64(view, object, psymval, addend, reladdr);
- }
- break;
- case elfcpp::R_X86_64_GOTPCREL:
- case elfcpp::R_X86_64_GOTPCRELX:
- case elfcpp::R_X86_64_REX_GOTPCRELX:
- {
- bool converted_p = false;
- if (rela.get_r_addend() == -4)
- {
- // Convert
- // mov foo@GOTPCREL(%rip), %reg
- // to lea foo(%rip), %reg.
- // if possible.
- if (!parameters->incremental()
- && ((gsym == NULL
- && rela.get_r_offset() >= 2
- && view[-2] == 0x8b
- && !psymval->is_ifunc_symbol())
- || (gsym != NULL
- && rela.get_r_offset() >= 2
- && Target_x86_64<size>::can_convert_mov_to_lea(gsym,
- r_type,
- 0,
- &view))))
- {
- view[-2] = 0x8d;
- Reloc_funcs::pcrela32(view, object, psymval, addend, address);
- converted_p = true;
- }
- // Convert
- // callq *foo@GOTPCRELX(%rip) to
- // addr32 callq foo
- // and jmpq *foo@GOTPCRELX(%rip) to
- // jmpq foo
- // nop
- else if (!parameters->incremental()
- && gsym != NULL
- && rela.get_r_offset() >= 2
- && Target_x86_64<size>::can_convert_callq_to_direct(gsym,
- r_type,
- 0,
- &view))
- {
- if (view[-1] == 0x15)
- {
- // Convert callq *foo@GOTPCRELX(%rip) to addr32 callq.
- // Opcode of addr32 is 0x67 and opcode of direct callq
- // is 0xe8.
- view[-2] = 0x67;
- view[-1] = 0xe8;
- // Convert GOTPCRELX to 32-bit pc relative reloc.
- Reloc_funcs::pcrela32(view, object, psymval, addend,
- address);
- converted_p = true;
- }
- else
- {
- // Convert jmpq *foo@GOTPCRELX(%rip) to
- // jmpq foo
- // nop
- // The opcode of direct jmpq is 0xe9.
- view[-2] = 0xe9;
- // The opcode of nop is 0x90.
- view[3] = 0x90;
- // Convert GOTPCRELX to 32-bit pc relative reloc. jmpq
- // is rip relative and since the instruction following
- // the jmpq is now the nop, offset the address by 1
- // byte. The start of the relocation also moves ahead
- // by 1 byte.
- Reloc_funcs::pcrela32(&view[-1], object, psymval, addend,
- address - 1);
- converted_p = true;
- }
- }
- }
- if (!converted_p)
- {
- if (gsym != NULL)
- {
- gold_assert(gsym->has_got_offset(GOT_TYPE_STANDARD));
- got_offset = (gsym->got_offset(GOT_TYPE_STANDARD)
- - target->got_size());
- }
- else
- {
- unsigned int r_sym = elfcpp::elf_r_sym<size>(rela.get_r_info());
- gold_assert(object->local_has_got_offset(r_sym,
- GOT_TYPE_STANDARD));
- got_offset = (object->local_got_offset(r_sym, GOT_TYPE_STANDARD)
- - target->got_size());
- }
- typename elfcpp::Elf_types<size>::Elf_Addr value;
- value = target->got_plt_section()->address() + got_offset;
- Reloc_funcs::pcrela32_check(view, value, addend, address);
- }
- }
- break;
- case elfcpp::R_X86_64_GOTPCREL64:
- {
- gold_assert(have_got_offset);
- typename elfcpp::Elf_types<size>::Elf_Addr value;
- value = target->got_plt_section()->address() + got_offset;
- Reloc_funcs::pcrela64(view, value, addend, address);
- }
- break;
- case elfcpp::R_X86_64_COPY:
- case elfcpp::R_X86_64_GLOB_DAT:
- case elfcpp::R_X86_64_JUMP_SLOT:
- case elfcpp::R_X86_64_RELATIVE:
- case elfcpp::R_X86_64_IRELATIVE:
- // These are outstanding tls relocs, which are unexpected when linking
- case elfcpp::R_X86_64_TPOFF64:
- case elfcpp::R_X86_64_DTPMOD64:
- case elfcpp::R_X86_64_TLSDESC:
- gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
- _("unexpected reloc %u in object file"),
- r_type);
- break;
- // These are initial tls relocs, which are expected when linking
- case elfcpp::R_X86_64_TLSGD: // Global-dynamic
- case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url)
- case elfcpp::R_X86_64_TLSDESC_CALL:
- case elfcpp::R_X86_64_TLSLD: // Local-dynamic
- case elfcpp::R_X86_64_DTPOFF32:
- case elfcpp::R_X86_64_DTPOFF64:
- case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
- case elfcpp::R_X86_64_TPOFF32: // Local-exec
- this->relocate_tls(relinfo, target, relnum, rela, r_type, gsym, psymval,
- view, address, view_size);
- break;
- case elfcpp::R_X86_64_SIZE32:
- case elfcpp::R_X86_64_SIZE64:
- default:
- gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
- _("unsupported reloc %u"),
- r_type);
- break;
- }
- if (rstatus == Reloc_funcs::RELOC_OVERFLOW)
- {
- if (gsym == NULL)
- {
- unsigned int r_sym = elfcpp::elf_r_sym<size>(rela.get_r_info());
- gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
- _("relocation overflow: "
- "reference to local symbol %u in %s"),
- r_sym, object->name().c_str());
- }
- else if (gsym->is_defined() && gsym->source() == Symbol::FROM_OBJECT)
- {
- gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
- _("relocation overflow: "
- "reference to '%s' defined in %s"),
- gsym->name(),
- gsym->object()->name().c_str());
- }
- else
- {
- gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
- _("relocation overflow: reference to '%s'"),
- gsym->name());
- }
- }
- return true;
- }
- // Perform a TLS relocation.
- template<int size>
- inline void
- Target_x86_64<size>::Relocate::relocate_tls(
- const Relocate_info<size, false>* relinfo,
- Target_x86_64<size>* target,
- size_t relnum,
- const elfcpp::Rela<size, false>& rela,
- unsigned int r_type,
- const Sized_symbol<size>* gsym,
- const Symbol_value<size>* psymval,
- unsigned char* view,
- typename elfcpp::Elf_types<size>::Elf_Addr address,
- section_size_type view_size)
- {
- Output_segment* tls_segment = relinfo->layout->tls_segment();
- const Sized_relobj_file<size, false>* object = relinfo->object;
- const elfcpp::Elf_Xword addend = rela.get_r_addend();
- elfcpp::Shdr<size, false> data_shdr(relinfo->data_shdr);
- bool is_executable = (data_shdr.get_sh_flags() & elfcpp::SHF_EXECINSTR) != 0;
- typename elfcpp::Elf_types<size>::Elf_Addr value = psymval->value(relinfo->object, 0);
- const bool is_final = (gsym == NULL
- ? !parameters->options().shared()
- : gsym->final_value_is_known());
- tls::Tls_optimization optimized_type
- = Target_x86_64<size>::optimize_tls_reloc(is_final, r_type);
- switch (r_type)
- {
- case elfcpp::R_X86_64_TLSGD: // Global-dynamic
- if (!is_executable && optimized_type == tls::TLSOPT_TO_LE)
- {
- // If this code sequence is used in a non-executable section,
- // we will not optimize the R_X86_64_DTPOFF32/64 relocation,
- // on the assumption that it's being used by itself in a debug
- // section. Therefore, in the unlikely event that the code
- // sequence appears in a non-executable section, we simply
- // leave it unoptimized.
- optimized_type = tls::TLSOPT_NONE;
- }
- if (optimized_type == tls::TLSOPT_TO_LE)
- {
- if (tls_segment == NULL)
- {
- gold_assert(parameters->errors()->error_count() > 0
- || issue_undefined_symbol_error(gsym));
- return;
- }
- this->tls_gd_to_le(relinfo, relnum, tls_segment,
- rela, r_type, value, view,
- view_size);
- break;
- }
- else
- {
- unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE
- ? GOT_TYPE_TLS_OFFSET
- : GOT_TYPE_TLS_PAIR);
- unsigned int got_offset;
- if (gsym != NULL)
- {
- gold_assert(gsym->has_got_offset(got_type));
- got_offset = gsym->got_offset(got_type) - target->got_size();
- }
- else
- {
- unsigned int r_sym = elfcpp::elf_r_sym<size>(rela.get_r_info());
- gold_assert(object->local_has_got_offset(r_sym, got_type));
- got_offset = (object->local_got_offset(r_sym, got_type)
- - target->got_size());
- }
- if (optimized_type == tls::TLSOPT_TO_IE)
- {
- value = target->got_plt_section()->address() + got_offset;
- this->tls_gd_to_ie(relinfo, relnum, rela, r_type,
- value, view, address, view_size);
- break;
- }
- else if (optimized_type == tls::TLSOPT_NONE)
- {
- // Relocate the field with the offset of the pair of GOT
- // entries.
- value = target->got_plt_section()->address() + got_offset;
- Relocate_functions<size, false>::pcrela32(view, value, addend,
- address);
- break;
- }
- }
- gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
- _("unsupported reloc %u"), r_type);
- break;
- case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url)
- case elfcpp::R_X86_64_TLSDESC_CALL:
- if (!is_executable && optimized_type == tls::TLSOPT_TO_LE)
- {
- // See above comment for R_X86_64_TLSGD.
- optimized_type = tls::TLSOPT_NONE;
- }
- if (optimized_type == tls::TLSOPT_TO_LE)
- {
- if (tls_segment == NULL)
- {
- gold_assert(parameters->errors()->error_count() > 0
- || issue_undefined_symbol_error(gsym));
- return;
- }
- this->tls_desc_gd_to_le(relinfo, relnum, tls_segment,
- rela, r_type, value, view,
- view_size);
- break;
- }
- else
- {
- unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE
- ? GOT_TYPE_TLS_OFFSET
- : GOT_TYPE_TLS_DESC);
- unsigned int got_offset = 0;
- if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC
- && optimized_type == tls::TLSOPT_NONE)
- {
- // We created GOT entries in the .got.tlsdesc portion of
- // the .got.plt section, but the offset stored in the
- // symbol is the offset within .got.tlsdesc.
- got_offset = (target->got_size()
- + target->got_plt_section()->data_size());
- }
- if (gsym != NULL)
- {
- gold_assert(gsym->has_got_offset(got_type));
- got_offset += gsym->got_offset(got_type) - target->got_size();
- }
- else
- {
- unsigned int r_sym = elfcpp::elf_r_sym<size>(rela.get_r_info());
- gold_assert(object->local_has_got_offset(r_sym, got_type));
- got_offset += (object->local_got_offset(r_sym, got_type)
- - target->got_size());
- }
- if (optimized_type == tls::TLSOPT_TO_IE)
- {
- value = target->got_plt_section()->address() + got_offset;
- this->tls_desc_gd_to_ie(relinfo, relnum,
- rela, r_type, value, view, address,
- view_size);
- break;
- }
- else if (optimized_type == tls::TLSOPT_NONE)
- {
- if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC)
- {
- // Relocate the field with the offset of the pair of GOT
- // entries.
- value = target->got_plt_section()->address() + got_offset;
- Relocate_functions<size, false>::pcrela32(view, value, addend,
- address);
- }
- break;
- }
- }
- gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
- _("unsupported reloc %u"), r_type);
- break;
- case elfcpp::R_X86_64_TLSLD: // Local-dynamic
- if (!is_executable && optimized_type == tls::TLSOPT_TO_LE)
- {
- // See above comment for R_X86_64_TLSGD.
- optimized_type = tls::TLSOPT_NONE;
- }
- if (optimized_type == tls::TLSOPT_TO_LE)
- {
- if (tls_segment == NULL)
- {
- gold_assert(parameters->errors()->error_count() > 0
- || issue_undefined_symbol_error(gsym));
- return;
- }
- this->tls_ld_to_le(relinfo, relnum, tls_segment, rela, r_type,
- value, view, view_size);
- break;
- }
- else if (optimized_type == tls::TLSOPT_NONE)
- {
- // Relocate the field with the offset of the GOT entry for
- // the module index.
- unsigned int got_offset;
- got_offset = (target->got_mod_index_entry(NULL, NULL, NULL)
- - target->got_size());
- value = target->got_plt_section()->address() + got_offset;
- Relocate_functions<size, false>::pcrela32(view, value, addend,
- address);
- break;
- }
- gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
- _("unsupported reloc %u"), r_type);
- break;
- case elfcpp::R_X86_64_DTPOFF32:
- // This relocation type is used in debugging information.
- // In that case we need to not optimize the value. If the
- // section is not executable, then we assume we should not
- // optimize this reloc. See comments above for R_X86_64_TLSGD,
- // R_X86_64_GOTPC32_TLSDESC, R_X86_64_TLSDESC_CALL, and
- // R_X86_64_TLSLD.
- if (optimized_type == tls::TLSOPT_TO_LE && is_executable)
- {
- if (tls_segment == NULL)
- {
- gold_assert(parameters->errors()->error_count() > 0
- || issue_undefined_symbol_error(gsym));
- return;
- }
- value -= tls_segment->memsz();
- }
- Relocate_functions<size, false>::rela32(view, value, addend);
- break;
- case elfcpp::R_X86_64_DTPOFF64:
- // See R_X86_64_DTPOFF32, just above, for why we check for is_executable.
- if (optimized_type == tls::TLSOPT_TO_LE && is_executable)
- {
- if (tls_segment == NULL)
- {
- gold_assert(parameters->errors()->error_count() > 0
- || issue_undefined_symbol_error(gsym));
- return;
- }
- value -= tls_segment->memsz();
- }
- Relocate_functions<size, false>::rela64(view, value, addend);
- break;
- case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
- if (gsym != NULL
- && gsym->is_undefined()
- && parameters->options().output_is_executable())
- {
- Target_x86_64<size>::Relocate::tls_ie_to_le(relinfo, relnum,
- NULL, rela,
- r_type, value, view,
- view_size);
- break;
- }
- else if (optimized_type == tls::TLSOPT_TO_LE)
- {
- if (tls_segment == NULL)
- {
- gold_assert(parameters->errors()->error_count() > 0
- || issue_undefined_symbol_error(gsym));
- return;
- }
- Target_x86_64<size>::Relocate::tls_ie_to_le(relinfo, relnum,
- tls_segment, rela,
- r_type, value, view,
- view_size);
- break;
- }
- else if (optimized_type == tls::TLSOPT_NONE)
- {
- // Relocate the field with the offset of the GOT entry for
- // the tp-relative offset of the symbol.
- unsigned int got_offset;
- if (gsym != NULL)
- {
- gold_assert(gsym->has_got_offset(GOT_TYPE_TLS_OFFSET));
- got_offset = (gsym->got_offset(GOT_TYPE_TLS_OFFSET)
- - target->got_size());
- }
- else
- {
- unsigned int r_sym = elfcpp::elf_r_sym<size>(rela.get_r_info());
- gold_assert(object->local_has_got_offset(r_sym,
- GOT_TYPE_TLS_OFFSET));
- got_offset = (object->local_got_offset(r_sym, GOT_TYPE_TLS_OFFSET)
- - target->got_size());
- }
- value = target->got_plt_section()->address() + got_offset;
- Relocate_functions<size, false>::pcrela32(view, value, addend,
- address);
- break;
- }
- gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
- _("unsupported reloc type %u"),
- r_type);
- break;
- case elfcpp::R_X86_64_TPOFF32: // Local-exec
- if (tls_segment == NULL)
- {
- gold_assert(parameters->errors()->error_count() > 0
- || issue_undefined_symbol_error(gsym));
- return;
- }
- value -= tls_segment->memsz();
- Relocate_functions<size, false>::rela32(view, value, addend);
- break;
- }
- }
- // Do a relocation in which we convert a TLS General-Dynamic to an
- // Initial-Exec.
- template<int size>
- inline void
- Target_x86_64<size>::Relocate::tls_gd_to_ie(
- const Relocate_info<size, false>* relinfo,
- size_t relnum,
- const elfcpp::Rela<size, false>& rela,
- unsigned int,
- typename elfcpp::Elf_types<size>::Elf_Addr value,
- unsigned char* view,
- typename elfcpp::Elf_types<size>::Elf_Addr address,
- section_size_type view_size)
- {
- // For SIZE == 64:
- // .byte 0x66; leaq foo@tlsgd(%rip),%rdi;
- // .word 0x6666; rex64; call __tls_get_addr@PLT
- // ==> movq %fs:0,%rax; addq x@gottpoff(%rip),%rax
- // .byte 0x66; leaq foo@tlsgd(%rip),%rdi;
- // .word 0x66; rex64; call *__tls_get_addr@GOTPCREL(%rip)
- // ==> movq %fs:0,%rax; addq x@gottpoff(%rip),%rax
- // For SIZE == 32:
- // leaq foo@tlsgd(%rip),%rdi;
- // .word 0x6666; rex64; call __tls_get_addr@PLT
- // ==> movl %fs:0,%eax; addq x@gottpoff(%rip),%rax
- // leaq foo@tlsgd(%rip),%rdi;
- // .word 0x66; rex64; call *__tls_get_addr@GOTPCREL(%rip)
- // ==> movl %fs:0,%eax; addq x@gottpoff(%rip),%rax
- tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 12);
- tls::check_tls(relinfo, relnum, rela.get_r_offset(),
- (memcmp(view + 4, "\x66\x66\x48\xe8", 4) == 0
- || memcmp(view + 4, "\x66\x48\xff", 3) == 0));
- if (size == 64)
- {
- tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size,
- -4);
- tls::check_tls(relinfo, relnum, rela.get_r_offset(),
- (memcmp(view - 4, "\x66\x48\x8d\x3d", 4) == 0));
- memcpy(view - 4, "\x64\x48\x8b\x04\x25\0\0\0\0\x48\x03\x05\0\0\0\0",
- 16);
- }
- else
- {
- tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size,
- -3);
- tls::check_tls(relinfo, relnum, rela.get_r_offset(),
- (memcmp(view - 3, "\x48\x8d\x3d", 3) == 0));
- memcpy(view - 3, "\x64\x8b\x04\x25\0\0\0\0\x48\x03\x05\0\0\0\0",
- 15);
- }
- const elfcpp::Elf_Xword addend = rela.get_r_addend();
- Relocate_functions<size, false>::pcrela32(view + 8, value, addend - 8,
- address);
- // The next reloc should be a PLT32 reloc against __tls_get_addr.
- // We can skip it.
- this->skip_call_tls_get_addr_ = true;
- }
- // Do a relocation in which we convert a TLS General-Dynamic to a
- // Local-Exec.
- template<int size>
- inline void
- Target_x86_64<size>::Relocate::tls_gd_to_le(
- const Relocate_info<size, false>* relinfo,
- size_t relnum,
- Output_segment* tls_segment,
- const elfcpp::Rela<size, false>& rela,
- unsigned int,
- typename elfcpp::Elf_types<size>::Elf_Addr value,
- unsigned char* view,
- section_size_type view_size)
- {
- // For SIZE == 64:
- // .byte 0x66; leaq foo@tlsgd(%rip),%rdi;
- // .word 0x6666; rex64; call __tls_get_addr@PLT
- // ==> movq %fs:0,%rax; leaq x@tpoff(%rax),%rax
- // .byte 0x66; leaq foo@tlsgd(%rip),%rdi;
- // .word 0x66; rex64; call *__tls_get_addr@GOTPCREL(%rip)
- // ==> movq %fs:0,%rax; leaq x@tpoff(%rax),%rax
- // For SIZE == 32:
- // leaq foo@tlsgd(%rip),%rdi;
- // .word 0x6666; rex64; call __tls_get_addr@PLT
- // ==> movl %fs:0,%eax; leaq x@tpoff(%rax),%rax
- // leaq foo@tlsgd(%rip),%rdi;
- // .word 0x66; rex64; call *__tls_get_addr@GOTPCREL(%rip)
- // ==> movl %fs:0,%eax; leaq x@tpoff(%rax),%rax
- tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 12);
- tls::check_tls(relinfo, relnum, rela.get_r_offset(),
- (memcmp(view + 4, "\x66\x66\x48\xe8", 4) == 0
- || memcmp(view + 4, "\x66\x48\xff", 3) == 0));
- if (size == 64)
- {
- tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size,
- -4);
- tls::check_tls(relinfo, relnum, rela.get_r_offset(),
- (memcmp(view - 4, "\x66\x48\x8d\x3d", 4) == 0));
- memcpy(view - 4, "\x64\x48\x8b\x04\x25\0\0\0\0\x48\x8d\x80\0\0\0\0",
- 16);
- }
- else
- {
- tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size,
- -3);
- tls::check_tls(relinfo, relnum, rela.get_r_offset(),
- (memcmp(view - 3, "\x48\x8d\x3d", 3) == 0));
- memcpy(view - 3, "\x64\x8b\x04\x25\0\0\0\0\x48\x8d\x80\0\0\0\0",
- 15);
- }
- value -= tls_segment->memsz();
- Relocate_functions<size, false>::rela32(view + 8, value, 0);
- // The next reloc should be a PLT32 reloc against __tls_get_addr.
- // We can skip it.
- this->skip_call_tls_get_addr_ = true;
- }
- // Do a TLSDESC-style General-Dynamic to Initial-Exec transition.
- template<int size>
- inline void
- Target_x86_64<size>::Relocate::tls_desc_gd_to_ie(
- const Relocate_info<size, false>* relinfo,
- size_t relnum,
- const elfcpp::Rela<size, false>& rela,
- unsigned int r_type,
- typename elfcpp::Elf_types<size>::Elf_Addr value,
- unsigned char* view,
- typename elfcpp::Elf_types<size>::Elf_Addr address,
- section_size_type view_size)
- {
- if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC)
- {
- // LP64: leaq foo@tlsdesc(%rip), %rax
- // ==> movq foo@gottpoff(%rip), %rax
- // X32: rex leal foo@tlsdesc(%rip), %eax
- // ==> rex movl foo@gottpoff(%rip), %eax
- tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
- tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4);
- tls::check_tls(relinfo, relnum, rela.get_r_offset(),
- (((view[-3] & 0xfb) == 0x48
- || (size == 32 && (view[-3] & 0xfb) == 0x40))
- && view[-2] == 0x8d
- && (view[-1] & 0xc7) == 0x05));
- view[-2] = 0x8b;
- const elfcpp::Elf_Xword addend = rela.get_r_addend();
- Relocate_functions<size, false>::pcrela32(view, value, addend, address);
- }
- else
- {
- // LP64: call *foo@tlscall(%rax)
- // ==> xchg %ax, %ax
- // X32: call *foo@tlscall(%eax)
- // ==> nopl (%rax)
- gold_assert(r_type == elfcpp::R_X86_64_TLSDESC_CALL);
- tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 2);
- int prefix = 0;
- if (size == 32 && view[0] == 0x67)
- {
- tls::check_range(relinfo, relnum, rela.get_r_offset(),
- view_size, 3);
- prefix = 1;
- }
- tls::check_tls(relinfo, relnum, rela.get_r_offset(),
- view[prefix] == 0xff && view[prefix + 1] == 0x10);
- if (prefix)
- {
- view[0] = 0x0f;
- view[1] = 0x1f;
- view[2] = 0x00;
- }
- else
- {
- view[0] = 0x66;
- view[1] = 0x90;
- }
- }
- }
- // Do a TLSDESC-style General-Dynamic to Local-Exec transition.
- template<int size>
- inline void
- Target_x86_64<size>::Relocate::tls_desc_gd_to_le(
- const Relocate_info<size, false>* relinfo,
- size_t relnum,
- Output_segment* tls_segment,
- const elfcpp::Rela<size, false>& rela,
- unsigned int r_type,
- typename elfcpp::Elf_types<size>::Elf_Addr value,
- unsigned char* view,
- section_size_type view_size)
- {
- if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC)
- {
- // LP64: leaq foo@tlsdesc(%rip), %rax
- // ==> movq foo@tpoff, %rax
- // X32: rex leal foo@tlsdesc(%rip), %eax
- // ==> rex movl foo@tpoff, %eax
- tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
- tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4);
- tls::check_tls(relinfo, relnum, rela.get_r_offset(),
- (((view[-3] & 0xfb) == 0x48
- || (size == 32 && (view[-3] & 0xfb) == 0x40))
- && view[-2] == 0x8d
- && (view[-1] & 0xc7) == 0x05));
- view[-3] = (view[-3] & 0x48) | ((view[-3] >> 2) & 1);
- view[-2] = 0xc7;
- view[-1] = 0xc0 | ((view[-1] >> 3) & 7);
- value -= tls_segment->memsz();
- Relocate_functions<size, false>::rela32(view, value, 0);
- }
- else
- {
- // LP64: call *foo@tlscall(%rax)
- // ==> xchg %ax, %ax
- // X32: call *foo@tlscall(%eax)
- // ==> nopl (%rax)
- gold_assert(r_type == elfcpp::R_X86_64_TLSDESC_CALL);
- tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 2);
- int prefix = 0;
- if (size == 32 && view[0] == 0x67)
- {
- tls::check_range(relinfo, relnum, rela.get_r_offset(),
- view_size, 3);
- prefix = 1;
- }
- tls::check_tls(relinfo, relnum, rela.get_r_offset(),
- view[prefix] == 0xff && view[prefix + 1] == 0x10);
- if (prefix)
- {
- view[0] = 0x0f;
- view[1] = 0x1f;
- view[2] = 0x00;
- }
- else
- {
- view[0] = 0x66;
- view[1] = 0x90;
- }
- }
- }
- template<int size>
- inline void
- Target_x86_64<size>::Relocate::tls_ld_to_le(
- const Relocate_info<size, false>* relinfo,
- size_t relnum,
- Output_segment*,
- const elfcpp::Rela<size, false>& rela,
- unsigned int,
- typename elfcpp::Elf_types<size>::Elf_Addr,
- unsigned char* view,
- section_size_type view_size)
- {
- // leaq foo@tlsld(%rip),%rdi; call __tls_get_addr@plt;
- // For SIZE == 64:
- // ... leq foo@dtpoff(%rax),%reg
- // ==> .word 0x6666; .byte 0x66; movq %fs:0,%rax ... leaq x@tpoff(%rax),%rdx
- // For SIZE == 32:
- // ... leq foo@dtpoff(%rax),%reg
- // ==> nopl 0x0(%rax); movl %fs:0,%eax ... leaq x@tpoff(%rax),%rdx
- // leaq foo@tlsld(%rip),%rdi; call *__tls_get_addr@GOTPCREL(%rip)
- // For SIZE == 64:
- // ... leq foo@dtpoff(%rax),%reg
- // ==> .word 0x6666; .byte 0x6666; movq %fs:0,%rax ... leaq x@tpoff(%rax),%rdx
- // For SIZE == 32:
- // ... leq foo@dtpoff(%rax),%reg
- // ==> nopw 0x0(%rax); movl %fs:0,%eax ... leaq x@tpoff(%rax),%rdx
- tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
- tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 9);
- tls::check_tls(relinfo, relnum, rela.get_r_offset(),
- view[-3] == 0x48 && view[-2] == 0x8d && view[-1] == 0x3d);
- tls::check_tls(relinfo, relnum, rela.get_r_offset(),
- view[4] == 0xe8 || view[4] == 0xff);
- if (view[4] == 0xe8)
- {
- if (size == 64)
- memcpy(view - 3, "\x66\x66\x66\x64\x48\x8b\x04\x25\0\0\0\0", 12);
- else
- memcpy(view - 3, "\x0f\x1f\x40\x00\x64\x8b\x04\x25\0\0\0\0", 12);
- }
- else
- {
- if (size == 64)
- memcpy(view - 3, "\x66\x66\x66\x66\x64\x48\x8b\x04\x25\0\0\0\0",
- 13);
- else
- memcpy(view - 3, "\x66\x0f\x1f\x40\x00\x64\x8b\x04\x25\0\0\0\0",
- 13);
- }
- // The next reloc should be a PLT32 reloc against __tls_get_addr.
- // We can skip it.
- this->skip_call_tls_get_addr_ = true;
- }
- // Do a relocation in which we convert a TLS Initial-Exec to a
- // Local-Exec.
- template<int size>
- inline void
- Target_x86_64<size>::Relocate::tls_ie_to_le(
- const Relocate_info<size, false>* relinfo,
- size_t relnum,
- Output_segment* tls_segment,
- const elfcpp::Rela<size, false>& rela,
- unsigned int,
- typename elfcpp::Elf_types<size>::Elf_Addr value,
- unsigned char* view,
- section_size_type view_size)
- {
- // We need to examine the opcodes to figure out which instruction we
- // are looking at.
- // movq foo@gottpoff(%rip),%reg ==> movq $YY,%reg
- // addq foo@gottpoff(%rip),%reg ==> addq $YY,%reg
- tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
- tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4);
- unsigned char op1 = view[-3];
- unsigned char op2 = view[-2];
- unsigned char op3 = view[-1];
- unsigned char reg = op3 >> 3;
- if (op2 == 0x8b)
- {
- // movq
- if (op1 == 0x4c)
- view[-3] = 0x49;
- else if (size == 32 && op1 == 0x44)
- view[-3] = 0x41;
- view[-2] = 0xc7;
- view[-1] = 0xc0 | reg;
- }
- else if (reg == 4)
- {
- // Special handling for %rsp.
- if (op1 == 0x4c)
- view[-3] = 0x49;
- else if (size == 32 && op1 == 0x44)
- view[-3] = 0x41;
- view[-2] = 0x81;
- view[-1] = 0xc0 | reg;
- }
- else
- {
- // addq
- if (op1 == 0x4c)
- view[-3] = 0x4d;
- else if (size == 32 && op1 == 0x44)
- view[-3] = 0x45;
- view[-2] = 0x8d;
- view[-1] = 0x80 | reg | (reg << 3);
- }
- if (tls_segment != NULL)
- value -= tls_segment->memsz();
- Relocate_functions<size, false>::rela32(view, value, 0);
- }
- // Relocate section data.
- template<int size>
- void
- Target_x86_64<size>::relocate_section(
- const Relocate_info<size, false>* relinfo,
- 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 address,
- section_size_type view_size,
- const Reloc_symbol_changes* reloc_symbol_changes)
- {
- typedef gold::Default_classify_reloc<elfcpp::SHT_RELA, size, false>
- Classify_reloc;
- gold_assert(sh_type == elfcpp::SHT_RELA);
- gold::relocate_section<size, false, Target_x86_64<size>, Relocate,
- gold::Default_comdat_behavior, Classify_reloc>(
- relinfo,
- this,
- prelocs,
- reloc_count,
- output_section,
- needs_special_offset_handling,
- view,
- address,
- view_size,
- reloc_symbol_changes);
- }
- // Apply an incremental relocation. Incremental relocations always refer
- // to global symbols.
- template<int size>
- void
- Target_x86_64<size>::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)
- {
- gold::apply_relocation<size, false, Target_x86_64<size>,
- typename Target_x86_64<size>::Relocate>(
- relinfo,
- this,
- r_offset,
- r_type,
- r_addend,
- gsym,
- view,
- address,
- view_size);
- }
- // Scan the relocs during a relocatable link.
- template<int size>
- void
- Target_x86_64<size>::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* rr)
- {
- typedef gold::Default_classify_reloc<elfcpp::SHT_RELA, size, false>
- Classify_reloc;
- typedef gold::Default_scan_relocatable_relocs<Classify_reloc>
- Scan_relocatable_relocs;
- gold_assert(sh_type == elfcpp::SHT_RELA);
- gold::scan_relocatable_relocs<size, false, Scan_relocatable_relocs>(
- symtab,
- layout,
- object,
- data_shndx,
- prelocs,
- reloc_count,
- output_section,
- needs_special_offset_handling,
- local_symbol_count,
- plocal_symbols,
- rr);
- }
- // Scan the relocs for --emit-relocs.
- template<int size>
- void
- Target_x86_64<size>::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)
- {
- typedef gold::Default_classify_reloc<elfcpp::SHT_RELA, size, false>
- Classify_reloc;
- typedef gold::Default_emit_relocs_strategy<Classify_reloc>
- Emit_relocs_strategy;
- gold_assert(sh_type == elfcpp::SHT_RELA);
- gold::scan_relocatable_relocs<size, false, Emit_relocs_strategy>(
- symtab,
- layout,
- object,
- data_shndx,
- prelocs,
- reloc_count,
- output_section,
- needs_special_offset_handling,
- local_symbol_count,
- plocal_syms,
- rr);
- }
- // Relocate a section during a relocatable link.
- template<int size>
- void
- Target_x86_64<size>::relocate_relocs(
- const Relocate_info<size, false>* relinfo,
- 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)
- {
- typedef gold::Default_classify_reloc<elfcpp::SHT_RELA, size, false>
- Classify_reloc;
- gold_assert(sh_type == elfcpp::SHT_RELA);
- gold::relocate_relocs<size, false, Classify_reloc>(
- relinfo,
- prelocs,
- reloc_count,
- output_section,
- offset_in_output_section,
- view,
- view_address,
- view_size,
- reloc_view,
- reloc_view_size);
- }
- // Return the value to use for a dynamic which requires special
- // treatment. This is how we support equality comparisons of function
- // pointers across shared library boundaries, as described in the
- // processor specific ABI supplement.
- template<int size>
- uint64_t
- Target_x86_64<size>::do_dynsym_value(const Symbol* gsym) const
- {
- gold_assert(gsym->is_from_dynobj() && gsym->has_plt_offset());
- return this->plt_address_for_global(gsym);
- }
- // Return a string used to fill a code section with nops to take up
- // the specified length.
- template<int size>
- std::string
- Target_x86_64<size>::do_code_fill(section_size_type length) const
- {
- if (length >= 16)
- {
- // Build a jmpq instruction to skip over the bytes.
- unsigned char jmp[5];
- jmp[0] = 0xe9;
- elfcpp::Swap_unaligned<32, false>::writeval(jmp + 1, length - 5);
- return (std::string(reinterpret_cast<char*>(&jmp[0]), 5)
- + std::string(length - 5, static_cast<char>(0x90)));
- }
- // Nop sequences of various lengths.
- const char nop1[1] = { '\x90' }; // nop
- const char nop2[2] = { '\x66', '\x90' }; // xchg %ax %ax
- const char nop3[3] = { '\x0f', '\x1f', '\x00' }; // nop (%rax)
- const char nop4[4] = { '\x0f', '\x1f', '\x40', // nop 0(%rax)
- '\x00'};
- const char nop5[5] = { '\x0f', '\x1f', '\x44', // nop 0(%rax,%rax,1)
- '\x00', '\x00' };
- const char nop6[6] = { '\x66', '\x0f', '\x1f', // nopw 0(%rax,%rax,1)
- '\x44', '\x00', '\x00' };
- const char nop7[7] = { '\x0f', '\x1f', '\x80', // nopl 0L(%rax)
- '\x00', '\x00', '\x00',
- '\x00' };
- const char nop8[8] = { '\x0f', '\x1f', '\x84', // nopl 0L(%rax,%rax,1)
- '\x00', '\x00', '\x00',
- '\x00', '\x00' };
- const char nop9[9] = { '\x66', '\x0f', '\x1f', // nopw 0L(%rax,%rax,1)
- '\x84', '\x00', '\x00',
- '\x00', '\x00', '\x00' };
- const char nop10[10] = { '\x66', '\x2e', '\x0f', // nopw %cs:0L(%rax,%rax,1)
- '\x1f', '\x84', '\x00',
- '\x00', '\x00', '\x00',
- '\x00' };
- const char nop11[11] = { '\x66', '\x66', '\x2e', // data16
- '\x0f', '\x1f', '\x84', // nopw %cs:0L(%rax,%rax,1)
- '\x00', '\x00', '\x00',
- '\x00', '\x00' };
- const char nop12[12] = { '\x66', '\x66', '\x66', // data16; data16
- '\x2e', '\x0f', '\x1f', // nopw %cs:0L(%rax,%rax,1)
- '\x84', '\x00', '\x00',
- '\x00', '\x00', '\x00' };
- const char nop13[13] = { '\x66', '\x66', '\x66', // data16; data16; data16
- '\x66', '\x2e', '\x0f', // nopw %cs:0L(%rax,%rax,1)
- '\x1f', '\x84', '\x00',
- '\x00', '\x00', '\x00',
- '\x00' };
- const char nop14[14] = { '\x66', '\x66', '\x66', // data16; data16; data16
- '\x66', '\x66', '\x2e', // data16
- '\x0f', '\x1f', '\x84', // nopw %cs:0L(%rax,%rax,1)
- '\x00', '\x00', '\x00',
- '\x00', '\x00' };
- const char nop15[15] = { '\x66', '\x66', '\x66', // data16; data16; data16
- '\x66', '\x66', '\x66', // data16; data16
- '\x2e', '\x0f', '\x1f', // nopw %cs:0L(%rax,%rax,1)
- '\x84', '\x00', '\x00',
- '\x00', '\x00', '\x00' };
- const char* nops[16] = {
- NULL,
- nop1, nop2, nop3, nop4, nop5, nop6, nop7,
- nop8, nop9, nop10, nop11, nop12, nop13, nop14, nop15
- };
- return std::string(nops[length], length);
- }
- // Return the addend to use for a target specific relocation. The
- // only target specific relocation is R_X86_64_TLSDESC for a local
- // symbol. We want to set the addend is the offset of the local
- // symbol in the TLS segment.
- template<int size>
- uint64_t
- Target_x86_64<size>::do_reloc_addend(void* arg, unsigned int r_type,
- uint64_t) const
- {
- gold_assert(r_type == elfcpp::R_X86_64_TLSDESC);
- uintptr_t intarg = reinterpret_cast<uintptr_t>(arg);
- gold_assert(intarg < this->tlsdesc_reloc_info_.size());
- const Tlsdesc_info& ti(this->tlsdesc_reloc_info_[intarg]);
- const Symbol_value<size>* psymval = ti.object->local_symbol(ti.r_sym);
- gold_assert(psymval->is_tls_symbol());
- // The value of a TLS symbol is the offset in the TLS segment.
- return psymval->value(ti.object, 0);
- }
- // Return the value to use for the base of a DW_EH_PE_datarel offset
- // in an FDE. Solaris and SVR4 use DW_EH_PE_datarel because their
- // assembler can not write out the difference between two labels in
- // different sections, so instead of using a pc-relative value they
- // use an offset from the GOT.
- template<int size>
- uint64_t
- Target_x86_64<size>::do_ehframe_datarel_base() const
- {
- gold_assert(this->global_offset_table_ != NULL);
- Symbol* sym = this->global_offset_table_;
- Sized_symbol<size>* ssym = static_cast<Sized_symbol<size>*>(sym);
- return ssym->value();
- }
- // FNOFFSET in section SHNDX in OBJECT is the start of a function
- // compiled with -fsplit-stack. The function calls non-split-stack
- // code. We have to change the function so that it always ensures
- // that it has enough stack space to run some random function.
- static const unsigned char cmp_insn_32[] = { 0x64, 0x3b, 0x24, 0x25 };
- static const unsigned char lea_r10_insn_32[] = { 0x44, 0x8d, 0x94, 0x24 };
- static const unsigned char lea_r11_insn_32[] = { 0x44, 0x8d, 0x9c, 0x24 };
- static const unsigned char cmp_insn_64[] = { 0x64, 0x48, 0x3b, 0x24, 0x25 };
- static const unsigned char lea_r10_insn_64[] = { 0x4c, 0x8d, 0x94, 0x24 };
- static const unsigned char lea_r11_insn_64[] = { 0x4c, 0x8d, 0x9c, 0x24 };
- template<int size>
- void
- Target_x86_64<size>::do_calls_non_split(Relobj* object, unsigned int shndx,
- section_offset_type fnoffset,
- section_size_type fnsize,
- const unsigned char*,
- size_t,
- unsigned char* view,
- section_size_type view_size,
- std::string* from,
- std::string* to) const
- {
- const char* const cmp_insn = reinterpret_cast<const char*>
- (size == 32 ? cmp_insn_32 : cmp_insn_64);
- const char* const lea_r10_insn = reinterpret_cast<const char*>
- (size == 32 ? lea_r10_insn_32 : lea_r10_insn_64);
- const char* const lea_r11_insn = reinterpret_cast<const char*>
- (size == 32 ? lea_r11_insn_32 : lea_r11_insn_64);
- const size_t cmp_insn_len =
- (size == 32 ? sizeof(cmp_insn_32) : sizeof(cmp_insn_64));
- const size_t lea_r10_insn_len =
- (size == 32 ? sizeof(lea_r10_insn_32) : sizeof(lea_r10_insn_64));
- const size_t lea_r11_insn_len =
- (size == 32 ? sizeof(lea_r11_insn_32) : sizeof(lea_r11_insn_64));
- const size_t nop_len = (size == 32 ? 7 : 8);
- // The function starts with a comparison of the stack pointer and a
- // field in the TCB. This is followed by a jump.
- // cmp %fs:NN,%rsp
- if (this->match_view(view, view_size, fnoffset, cmp_insn, cmp_insn_len)
- && fnsize > nop_len + 1)
- {
- // We will call __morestack if the carry flag is set after this
- // comparison. We turn the comparison into an stc instruction
- // and some nops.
- view[fnoffset] = '\xf9';
- this->set_view_to_nop(view, view_size, fnoffset + 1, nop_len);
- }
- // lea NN(%rsp),%r10
- // lea NN(%rsp),%r11
- else if ((this->match_view(view, view_size, fnoffset,
- lea_r10_insn, lea_r10_insn_len)
- || this->match_view(view, view_size, fnoffset,
- lea_r11_insn, lea_r11_insn_len))
- && fnsize > 8)
- {
- // This is loading an offset from the stack pointer for a
- // comparison. The offset is negative, so we decrease the
- // offset by the amount of space we need for the stack. This
- // means we will avoid calling __morestack if there happens to
- // be plenty of space on the stack already.
- unsigned char* pval = view + fnoffset + 4;
- uint32_t val = elfcpp::Swap_unaligned<32, false>::readval(pval);
- val -= parameters->options().split_stack_adjust_size();
- elfcpp::Swap_unaligned<32, false>::writeval(pval, val);
- }
- else
- {
- if (!object->has_no_split_stack())
- object->error(_("failed to match split-stack sequence at "
- "section %u offset %0zx"),
- shndx, static_cast<size_t>(fnoffset));
- return;
- }
- // We have to change the function so that it calls
- // __morestack_non_split instead of __morestack. The former will
- // allocate additional stack space.
- *from = "__morestack";
- *to = "__morestack_non_split";
- }
- // The selector for x86_64 object files. Note this is never instantiated
- // directly. It's only used in Target_selector_x86_64_nacl, below.
- template<int size>
- class Target_selector_x86_64 : public Target_selector_freebsd
- {
- public:
- Target_selector_x86_64()
- : Target_selector_freebsd(elfcpp::EM_X86_64, size, false,
- (size == 64
- ? "elf64-x86-64" : "elf32-x86-64"),
- (size == 64
- ? "elf64-x86-64-freebsd"
- : "elf32-x86-64-freebsd"),
- (size == 64 ? "elf_x86_64" : "elf32_x86_64"))
- { }
- Target*
- do_instantiate_target()
- { return new Target_x86_64<size>(); }
- };
- // NaCl variant. It uses different PLT contents.
- template<int size>
- class Output_data_plt_x86_64_nacl : public Output_data_plt_x86_64<size>
- {
- public:
- Output_data_plt_x86_64_nacl(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_nacl(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 = 64;
- // The first entry in the PLT.
- 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];
- };
- template<int size>
- class Target_x86_64_nacl : public Target_x86_64<size>
- {
- public:
- Target_x86_64_nacl()
- : Target_x86_64<size>(&x86_64_nacl_info)
- { }
- 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)
- {
- return new Output_data_plt_x86_64_nacl<size>(layout, got, got_plt,
- 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)
- {
- return new Output_data_plt_x86_64_nacl<size>(layout, got, got_plt,
- got_irelative,
- plt_count);
- }
- virtual std::string
- do_code_fill(section_size_type length) const;
- private:
- static const Target::Target_info x86_64_nacl_info;
- };
- template<>
- const Target::Target_info Target_x86_64_nacl<64>::x86_64_nacl_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
- "/lib64/ld-nacl-x86-64.so.1", // dynamic_linker
- 0x20000, // default_text_segment_address
- 0x10000, // abi_pagesize (overridable by -z max-page-size)
- 0x10000, // common_pagesize (overridable by -z common-page-size)
- true, // isolate_execinstr
- 0x10000000, // 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_nacl<32>::x86_64_nacl_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
- "/lib/ld-nacl-x86-64.so.1", // dynamic_linker
- 0x20000, // default_text_segment_address
- 0x10000, // abi_pagesize (overridable by -z max-page-size)
- 0x10000, // common_pagesize (overridable by -z common-page-size)
- true, // isolate_execinstr
- 0x10000000, // 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
- };
- #define NACLMASK 0xe0 // 32-byte alignment mask.
- // The first entry in the PLT.
- template<int size>
- const unsigned char
- Output_data_plt_x86_64_nacl<size>::first_plt_entry[plt_entry_size] =
- {
- 0xff, 0x35, // pushq contents of memory address
- 0, 0, 0, 0, // replaced with address of .got + 8
- 0x4c, 0x8b, 0x1d, // mov GOT+16(%rip), %r11
- 0, 0, 0, 0, // replaced with address of .got + 16
- 0x41, 0x83, 0xe3, NACLMASK, // and $-32, %r11d
- 0x4d, 0x01, 0xfb, // add %r15, %r11
- 0x41, 0xff, 0xe3, // jmpq *%r11
- // 9-byte nop sequence to pad out to the next 32-byte boundary.
- 0x66, 0x0f, 0x1f, 0x84, 0, 0, 0, 0, 0, // nopw 0x0(%rax,%rax,1)
- // 32 bytes of nop to pad out to the standard size
- 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, // excess data32 prefixes
- 0x2e, 0x0f, 0x1f, 0x84, 0, 0, 0, 0, 0, // nopw %cs:0x0(%rax,%rax,1)
- 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, // excess data32 prefixes
- 0x2e, 0x0f, 0x1f, 0x84, 0, 0, 0, 0, 0, // nopw %cs:0x0(%rax,%rax,1)
- 0x66, // excess data32 prefix
- 0x90 // nop
- };
- template<int size>
- void
- Output_data_plt_x86_64_nacl<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);
- elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
- (got_address + 8
- - (plt_address + 2 + 4)));
- elfcpp::Swap_unaligned<32, false>::writeval(pov + 9,
- (got_address + 16
- - (plt_address + 9 + 4)));
- }
- // Subsequent entries in the PLT.
- template<int size>
- const unsigned char
- Output_data_plt_x86_64_nacl<size>::plt_entry[plt_entry_size] =
- {
- 0x4c, 0x8b, 0x1d, // mov name@GOTPCREL(%rip),%r11
- 0, 0, 0, 0, // replaced with address of symbol in .got
- 0x41, 0x83, 0xe3, NACLMASK, // and $-32, %r11d
- 0x4d, 0x01, 0xfb, // add %r15, %r11
- 0x41, 0xff, 0xe3, // jmpq *%r11
- // 15-byte nop sequence to pad out to the next 32-byte boundary.
- 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, // excess data32 prefixes
- 0x2e, 0x0f, 0x1f, 0x84, 0, 0, 0, 0, 0, // nopw %cs:0x0(%rax,%rax,1)
- // Lazy GOT entries point here (32-byte aligned).
- 0x68, // pushq immediate
- 0, 0, 0, 0, // replaced with index into relocation table
- 0xe9, // jmp relative
- 0, 0, 0, 0, // replaced with offset to start of .plt0
- // 22 bytes of nop to pad out to the standard size.
- 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, // excess data32 prefixes
- 0x2e, 0x0f, 0x1f, 0x84, 0, 0, 0, 0, 0, // nopw %cs:0x0(%rax,%rax,1)
- 0x0f, 0x1f, 0x80, 0, 0, 0, 0, // nopl 0x0(%rax)
- };
- template<int size>
- unsigned int
- Output_data_plt_x86_64_nacl<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)
- {
- memcpy(pov, plt_entry, plt_entry_size);
- elfcpp::Swap_unaligned<32, false>::writeval(pov + 3,
- (got_address + got_offset
- - (plt_address + plt_offset
- + 3 + 4)));
- elfcpp::Swap_unaligned<32, false>::writeval(pov + 33, plt_index);
- elfcpp::Swap_unaligned<32, false>::writeval(pov + 38,
- - (plt_offset + 38 + 4));
- return 32;
- }
- // The reserved TLSDESC entry in the PLT.
- template<int size>
- const unsigned char
- Output_data_plt_x86_64_nacl<size>::tlsdesc_plt_entry[plt_entry_size] =
- {
- 0xff, 0x35, // pushq x(%rip)
- 0, 0, 0, 0, // replaced with address of linkmap GOT entry (at PLTGOT + 8)
- 0x4c, 0x8b, 0x1d, // mov y(%rip),%r11
- 0, 0, 0, 0, // replaced with offset of reserved TLSDESC_GOT entry
- 0x41, 0x83, 0xe3, NACLMASK, // and $-32, %r11d
- 0x4d, 0x01, 0xfb, // add %r15, %r11
- 0x41, 0xff, 0xe3, // jmpq *%r11
- // 41 bytes of nop to pad out to the standard size.
- 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, // excess data32 prefixes
- 0x2e, 0x0f, 0x1f, 0x84, 0, 0, 0, 0, 0, // nopw %cs:0x0(%rax,%rax,1)
- 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, // excess data32 prefixes
- 0x2e, 0x0f, 0x1f, 0x84, 0, 0, 0, 0, 0, // nopw %cs:0x0(%rax,%rax,1)
- 0x66, 0x66, // excess data32 prefixes
- 0x2e, 0x0f, 0x1f, 0x84, 0, 0, 0, 0, 0, // nopw %cs:0x0(%rax,%rax,1)
- };
- template<int size>
- void
- Output_data_plt_x86_64_nacl<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
- + 2 + 4)));
- elfcpp::Swap_unaligned<32, false>::writeval(pov + 9,
- (got_base
- + tlsdesc_got_offset
- - (plt_address + plt_offset
- + 9 + 4)));
- }
- // The .eh_frame unwind information for the PLT.
- template<int size>
- const unsigned char
- Output_data_plt_x86_64_nacl<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 + 58, // Advance 58 to __PLT__ + 64.
- elfcpp::DW_CFA_def_cfa_expression, // DW_CFA_def_cfa_expression.
- 13, // Block length.
- elfcpp::DW_OP_breg7, 8, // Push %rsp + 8.
- elfcpp::DW_OP_breg16, 0, // Push %rip.
- elfcpp::DW_OP_const1u, 63, // Push 0x3f.
- elfcpp::DW_OP_and, // & (%rip & 0x3f).
- elfcpp::DW_OP_const1u, 37, // Push 0x25.
- elfcpp::DW_OP_ge, // >= ((%rip & 0x3f) >= 0x25)
- elfcpp::DW_OP_lit3, // Push 3.
- elfcpp::DW_OP_shl, // << (((%rip & 0x3f) >= 0x25) << 3)
- elfcpp::DW_OP_plus, // + ((((%rip&0x3f)>=0x25)<<3)+%rsp+8
- elfcpp::DW_CFA_nop, // Align to 32 bytes.
- elfcpp::DW_CFA_nop
- };
- // Return a string used to fill a code section with nops.
- // For NaCl, long NOPs are only valid if they do not cross
- // bundle alignment boundaries, so keep it simple with one-byte NOPs.
- template<int size>
- std::string
- Target_x86_64_nacl<size>::do_code_fill(section_size_type length) const
- {
- return std::string(length, static_cast<char>(0x90));
- }
- // The selector for x86_64-nacl object files.
- template<int size>
- class Target_selector_x86_64_nacl
- : public Target_selector_nacl<Target_selector_x86_64<size>,
- Target_x86_64_nacl<size> >
- {
- public:
- Target_selector_x86_64_nacl()
- : Target_selector_nacl<Target_selector_x86_64<size>,
- Target_x86_64_nacl<size> >("x86-64",
- size == 64
- ? "elf64-x86-64-nacl"
- : "elf32-x86-64-nacl",
- size == 64
- ? "elf_x86_64_nacl"
- : "elf32_x86_64_nacl")
- { }
- };
- Target_selector_x86_64_nacl<64> target_selector_x86_64;
- Target_selector_x86_64_nacl<32> target_selector_x32;
- } // End anonymous namespace.
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