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Diffstat (limited to 'binutils-2.25/gold/x86_64.cc')
| -rw-r--r-- | binutils-2.25/gold/x86_64.cc | 4836 |
1 files changed, 4836 insertions, 0 deletions
diff --git a/binutils-2.25/gold/x86_64.cc b/binutils-2.25/gold/x86_64.cc new file mode 100644 index 00000000..b95d2ed8 --- /dev/null +++ b/binutils-2.25/gold/x86_64.cc @@ -0,0 +1,4836 @@ +// x86_64.cc -- x86_64 target support for gold. + +// Copyright 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 +// 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 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_space* got_plt, + Output_data_space* got_irelative) + : Output_section_data(addralign), layout_(layout), 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_space* got_plt, + Output_data_space* got_irelative, + unsigned int plt_count) + : Output_section_data((plt_count + 1) * plt_entry_size, + plt_entry_size, false), + layout_(layout), 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; } + + // Return the 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*); + + // Return the PLT address to use for a local symbol. + uint64_t + address_for_local(const Relobj*, unsigned int symndx); + + // Add .eh_frame information for the PLT. + void + add_eh_frame(Layout* layout) + { this->do_add_eh_frame(layout); } + + protected: + // 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; + + 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*); + + // A pointer to the Layout class, so that we can find the .dynamic + // section when we write out the GOT PLT section. + Layout* layout_; + // 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_space* 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_space* 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_space* 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]; +}; + +// 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) + { } + + // 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*); + + // 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, + const Relocatable_relocs*, + 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 relocation types. + bool + do_can_check_for_function_pointers() const + { return !parameters->options().pie(); } + + // 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, + 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; + + // 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_space* 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_space* 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_space* got_plt, + Output_data_space* got_irelative) + { + return new Output_data_plt_x86_64_standard<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_space* got_plt, + Output_data_space* got_irelative, + unsigned int plt_count) + { + return new Output_data_plt_x86_64_standard<size>(layout, got, got_plt, + got_irelative, + 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(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>*, Target_x86_64*, + Output_section*, + 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); + + 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, + Output_segment* tls_segment, + 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, + Output_segment* tls_segment, + 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_; + }; + + // A class which returns the size required for a relocation type, + // used while scanning relocs during a relocatable link. + class Relocatable_size_for_reloc + { + public: + unsigned int + get_size_for_reloc(unsigned int, Relobj*); + }; + + // 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_space* + 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) + { + this->copy_relocs_.copy_reloc(symtab, layout, + symtab->get_sized_symbol<size>(sym), + object, shndx, output_section, + reloc, this->rela_dyn_section(layout)); + } + + // 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_space* 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_; +}; + +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 +}; + +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 +}; + +// 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_space(8, "** GOT PLT"); + 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_; +} + +// 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_data_space* 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>::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>::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() +{ + unsigned int count = this->count_ + this->irelative_count_; + if (this->has_tlsdesc_entry()) + ++count; + this->set_data_size((count + 1) * 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) +{ + memcpy(pov, plt_entry, plt_entry_size); + elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, + (got_address + got_offset + - (plt_address + plt_offset + + 6))); + + 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))); +} + +// 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 +}; + +// 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(); + + unsigned char* got_pov = got_view; + + // 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. + Output_section* dynamic = this->layout_->dynamic_section(); + uint32_t dynamic_addr = dynamic == NULL ? 0 : dynamic->address(); + elfcpp::Swap<64, false>::writeval(got_pov, dynamic_addr); + got_pov += 8; + memset(got_pov, 0, 16); + got_pov += 16; + + 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); +} + +// 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()); + } +} + +// 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 +{ + 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 +{ + 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_space((plt_count + 3) * 8, 8, "** GOT PLT"); + 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_PC16: + case elfcpp::R_X86_64_PC8: + case elfcpp::R_X86_64_GOTOFF64: + return Symbol::RELATIVE_REF; + + case elfcpp::R_X86_64_PLT32: + case elfcpp::R_X86_64_PLTOFF64: + return Symbol::FUNCTION_CALL | Symbol::RELATIVE_REF; + + case elfcpp::R_X86_64_GOT64: + case elfcpp::R_X86_64_GOT32: + case elfcpp::R_X86_64_GOTPCREL64: + case elfcpp::R_X86_64_GOTPCREL: + case elfcpp::R_X86_64_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: + // 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 + object->error(_("requires dynamic %s reloc against '%s' which may " + "overflow at runtime; recompile with -fPIC"), + (r_type == elfcpp::R_X86_64_32 + ? "R_X86_64_32" + : "R_X86_64_PC32"), + 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_PC16: + case elfcpp::R_X86_64_PC8: + break; + + case elfcpp::R_X86_64_PLT32: + // 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_GOTPLT64: + { + // The symbol requires a GOT entry. + Output_data_got<64, false>* got = target->got_section(symtab, layout); + 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(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_GOTPLT64: + { + 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>* , + unsigned int , + Output_section* , + const elfcpp::Rela<size, false>& , + unsigned int r_type, + const elfcpp::Sym<size, false>&) +{ + // When building a shared library, do not fold any local symbols as it is + // not possible to distinguish pointer taken versus a call by looking at + // the relocation types. + return (parameters->options().shared() + || possible_function_pointer_reloc(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>* , + unsigned int , + Output_section* , + const elfcpp::Rela<size, false>& , + unsigned int r_type, + Symbol* gsym) +{ + // When building a shared library, do not fold symbols whose visibility + // is hidden, internal or protected. + return ((parameters->options().shared() + && (gsym->visibility() == elfcpp::STV_INTERNAL + || gsym->visibility() == elfcpp::STV_PROTECTED + || gsym->visibility() == elfcpp::STV_HIDDEN)) + || possible_function_pointer_reloc(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 (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_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 (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_GOTPLT64: + { + // The symbol requires a GOT entry. + Output_data_got<64, false>* got = target->got_section(symtab, layout); + 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); + } + } + } + // For GOTPLT64, we also need a PLT entry (but only if the + // symbol is not fully resolved). + if (r_type == elfcpp::R_X86_64_GOTPLT64 + && !gsym->final_value_is_known()) + target->make_plt_entry(symtab, layout, gsym); + } + break; + + case elfcpp::R_X86_64_PLT32: + // 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 + { + const bool is_final = gsym->final_value_is_known(); + 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) +{ + + if (sh_type == elfcpp::SHT_REL) + { + return; + } + + gold::gc_process_relocs<size, false, Target_x86_64<size>, elfcpp::SHT_RELA, + typename Target_x86_64<size>::Scan, + typename Target_x86_64<size>::Relocatable_size_for_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) +{ + 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>, elfcpp::SHT_RELA, + typename Target_x86_64<size>::Scan>( + 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()); + } +} + +// Perform a relocation. + +template<int size> +inline bool +Target_x86_64<size>::Relocate::relocate( + const Relocate_info<size, false>* relinfo, + Target_x86_64<size>* target, + Output_section*, + 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) +{ + if (this->skip_call_tls_get_addr_) + { + if ((r_type != elfcpp::R_X86_64_PLT32 + && 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")); + } + 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; + unsigned 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_GOTPCREL: + 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; + } + + 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: + Relocate_functions<size, false>::rela64(view, object, psymval, addend); + break; + + case elfcpp::R_X86_64_PC64: + Relocate_functions<size, false>::pcrela64(view, object, psymval, addend, + address); + break; + + case elfcpp::R_X86_64_32: + // FIXME: we need to verify that value + addend fits into 32 bits: + // uint64_t x = value + addend; + // x == static_cast<uint64_t>(static_cast<uint32_t>(x)) + // Likewise for other <=32-bit relocations (but see R_X86_64_32S). + Relocate_functions<size, false>::rela32(view, object, psymval, addend); + break; + + case elfcpp::R_X86_64_32S: + // FIXME: we need to verify that value + addend fits into 32 bits: + // int64_t x = value + addend; // note this quantity is signed! + // x == static_cast<int64_t>(static_cast<int32_t>(x)) + Relocate_functions<size, false>::rela32(view, object, psymval, addend); + break; + + case elfcpp::R_X86_64_PC32: + Relocate_functions<size, false>::pcrela32(view, object, psymval, addend, + address); + break; + + case elfcpp::R_X86_64_16: + Relocate_functions<size, false>::rela16(view, object, psymval, addend); + break; + + case elfcpp::R_X86_64_PC16: + Relocate_functions<size, false>::pcrela16(view, object, psymval, addend, + address); + break; + + case elfcpp::R_X86_64_8: + Relocate_functions<size, false>::rela8(view, object, psymval, addend); + break; + + case elfcpp::R_X86_64_PC8: + Relocate_functions<size, false>::pcrela8(view, object, psymval, addend, + address); + break; + + case elfcpp::R_X86_64_PLT32: + 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(). + Relocate_functions<size, false>::pcrela32(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; + got_address = target->got_section(NULL, NULL)->address(); + Relocate_functions<size, false>::rela64(view, object, psymval, + addend - got_address); + } + + case elfcpp::R_X86_64_GOT32: + gold_assert(have_got_offset); + Relocate_functions<size, false>::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(); + Relocate_functions<size, false>::pcrela32(view, value, addend, address); + } + break; + + case elfcpp::R_X86_64_GOT64: + // The ABI doc says "Like GOT64, but indicates a PLT entry is needed." + // Since we always add a PLT entry, this is equivalent. + case elfcpp::R_X86_64_GOTPLT64: + gold_assert(have_got_offset); + Relocate_functions<size, false>::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(); + Relocate_functions<size, false>::pcrela64(view, value, addend, address); + } + break; + + case elfcpp::R_X86_64_GOTOFF64: + { + typename elfcpp::Elf_types<size>::Elf_Addr value; + value = (psymval->value(object, 0) + - target->got_plt_section()->address()); + Relocate_functions<size, false>::rela64(view, value, addend); + } + break; + + case elfcpp::R_X86_64_GOTPCREL: + { + gold_assert(have_got_offset); + typename elfcpp::Elf_types<size>::Elf_Addr value; + value = target->got_plt_section()->address() + got_offset; + Relocate_functions<size, false>::pcrela32(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; + Relocate_functions<size, false>::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; + } + + 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, tls_segment, 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) + { + if (tls_segment == NULL) + { + gold_assert(parameters->errors()->error_count() > 0 + || issue_undefined_symbol_error(gsym)); + return; + } + value = target->got_plt_section()->address() + got_offset; + this->tls_desc_gd_to_ie(relinfo, relnum, tls_segment, + 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 (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, + Output_segment*, + 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 + // ==> movq %fs:0,%rax; addq x@gottpoff(%rip),%rax + // For SIZE == 32: + // leaq foo@tlsgd(%rip),%rdi; + // .word 0x6666; rex64; call __tls_get_addr + // ==> 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)); + + 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 + // ==> movq %fs:0,%rax; leaq x@tpoff(%rax),%rax + // For SIZE == 32: + // leaq foo@tlsgd(%rip),%rdi; + // .word 0x6666; rex64; call __tls_get_addr + // ==> 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)); + + 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, + Output_segment*, + 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) + { + // leaq foo@tlsdesc(%rip), %rax + // ==> movq foo@gottpoff(%rip), %rax + 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] == 0x48 && view[-2] == 0x8d && view[-1] == 0x05); + view[-2] = 0x8b; + const elfcpp::Elf_Xword addend = rela.get_r_addend(); + Relocate_functions<size, false>::pcrela32(view, value, addend, address); + } + else + { + // call *foo@tlscall(%rax) + // ==> nop; nop + gold_assert(r_type == elfcpp::R_X86_64_TLSDESC_CALL); + tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 2); + tls::check_tls(relinfo, relnum, rela.get_r_offset(), + view[0] == 0xff && view[1] == 0x10); + 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) + { + // leaq foo@tlsdesc(%rip), %rax + // ==> movq foo@tpoff, %rax + 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] == 0x48 && view[-2] == 0x8d && view[-1] == 0x05); + view[-2] = 0xc7; + view[-1] = 0xc0; + value -= tls_segment->memsz(); + Relocate_functions<size, false>::rela32(view, value, 0); + } + else + { + // call *foo@tlscall(%rax) + // ==> nop; nop + gold_assert(r_type == elfcpp::R_X86_64_TLSDESC_CALL); + tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 2); + tls::check_tls(relinfo, relnum, rela.get_r_offset(), + view[0] == 0xff && view[1] == 0x10); + 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 + + 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); + + 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); + + // 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; + view[-2] = 0xc7; + view[-1] = 0xc0 | reg; + } + else if (reg == 4) + { + // Special handling for %rsp. + if (op1 == 0x4c) + view[-3] = 0x49; + view[-2] = 0x81; + view[-1] = 0xc0 | reg; + } + else + { + // addq + if (op1 == 0x4c) + view[-3] = 0x4d; + view[-2] = 0x8d; + view[-1] = 0x80 | reg | (reg << 3); + } + + 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) +{ + gold_assert(sh_type == elfcpp::SHT_RELA); + + gold::relocate_section<size, false, Target_x86_64<size>, elfcpp::SHT_RELA, + typename Target_x86_64<size>::Relocate, + gold::Default_comdat_behavior>( + 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); +} + +// Return the size of a relocation while scanning during a relocatable +// link. + +template<int size> +unsigned int +Target_x86_64<size>::Relocatable_size_for_reloc::get_size_for_reloc( + unsigned int r_type, + Relobj* object) +{ + 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_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 0; + + case elfcpp::R_X86_64_64: + case elfcpp::R_X86_64_PC64: + case elfcpp::R_X86_64_GOTOFF64: + case elfcpp::R_X86_64_GOTPC64: + case elfcpp::R_X86_64_PLTOFF64: + case elfcpp::R_X86_64_GOT64: + case elfcpp::R_X86_64_GOTPCREL64: + case elfcpp::R_X86_64_GOTPCREL: + case elfcpp::R_X86_64_GOTPLT64: + return 8; + + case elfcpp::R_X86_64_32: + case elfcpp::R_X86_64_32S: + case elfcpp::R_X86_64_PC32: + case elfcpp::R_X86_64_PLT32: + case elfcpp::R_X86_64_GOTPC32: + case elfcpp::R_X86_64_GOT32: + return 4; + + case elfcpp::R_X86_64_16: + case elfcpp::R_X86_64_PC16: + return 2; + + case elfcpp::R_X86_64_8: + case elfcpp::R_X86_64_PC8: + return 1; + + 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: + object->error(_("unexpected reloc %u in object file"), r_type); + return 0; + + case elfcpp::R_X86_64_SIZE32: + case elfcpp::R_X86_64_SIZE64: + default: + object->error(_("unsupported reloc %u against local symbol"), r_type); + return 0; + } +} + +// 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) +{ + gold_assert(sh_type == elfcpp::SHT_RELA); + + typedef gold::Default_scan_relocatable_relocs<elfcpp::SHT_RELA, + Relocatable_size_for_reloc> Scan_relocatable_relocs; + + gold::scan_relocatable_relocs<size, false, elfcpp::SHT_RELA, + Scan_relocatable_relocs>( + symtab, + layout, + object, + data_shndx, + prelocs, + reloc_count, + output_section, + needs_special_offset_handling, + local_symbol_count, + plocal_symbols, + 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, + const Relocatable_relocs* rr, + 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) +{ + gold_assert(sh_type == elfcpp::SHT_RELA); + + gold::relocate_relocs<size, false, elfcpp::SHT_RELA>( + relinfo, + prelocs, + reloc_count, + output_section, + offset_in_output_section, + rr, + 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. + +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, + unsigned char* view, + section_size_type view_size, + std::string* from, + std::string* to) const +{ + // 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, "\x64\x48\x3b\x24\x25", 5) + && fnsize > 9) + { + // 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, 8); + } + // lea NN(%rsp),%r10 + // lea NN(%rsp),%r11 + else if ((this->match_view(view, view_size, fnoffset, + "\x4c\x8d\x94\x24", 4) + || this->match_view(view, view_size, fnoffset, + "\x4c\x8d\x9c\x24", 4)) + && 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_space* 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_space* 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_space* 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_space* 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 +}; + +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 +}; + +#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. + 0x2e, 0x0f, 0x1f, 0x84, 0, 0, 0, 0, 0, // nopl %cs: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. |