| // x86_64.cc -- x86_64 target support for gold. |
| |
| // Copyright 2006, 2007, 2008, 2009, 2010 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 "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 "gc.h" |
| #include "icf.h" |
| |
| namespace |
| { |
| |
| using namespace gold; |
| |
| // A class to handle the PLT data. |
| |
| class Output_data_plt_x86_64 : public Output_section_data |
| { |
| public: |
| typedef Output_data_reloc<elfcpp::SHT_RELA, true, 64, false> Reloc_section; |
| |
| Output_data_plt_x86_64(Symbol_table*, Layout*, Output_data_got<64, false>*, |
| Output_data_space*); |
| |
| // Add an entry to the PLT. |
| void |
| add_entry(Symbol* gsym); |
| |
| // Add an entry to the PLT for a local STT_GNU_IFUNC symbol. |
| unsigned int |
| add_local_ifunc_entry(Sized_relobj<64, false>* relobj, |
| unsigned int local_sym_index); |
| |
| // 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_ + 1) * 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 the number of PLT entries. |
| unsigned int |
| entry_count() const |
| { return this->count_; } |
| |
| // Return the offset of the first non-reserved PLT entry. |
| static unsigned int |
| first_plt_entry_offset() |
| { return plt_entry_size; } |
| |
| // Return the size of a PLT entry. |
| static unsigned int |
| get_plt_entry_size() |
| { return plt_entry_size; } |
| |
| protected: |
| 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")); } |
| |
| 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 unsigned char first_plt_entry[plt_entry_size]; |
| |
| // Other entries in the PLT for an executable. |
| static unsigned char plt_entry[plt_entry_size]; |
| |
| // The reserved TLSDESC entry in the PLT for an executable. |
| static unsigned char tlsdesc_plt_entry[plt_entry_size]; |
| |
| // Set the final size. |
| void |
| set_final_data_size(); |
| |
| // Write out the PLT data. |
| void |
| do_write(Output_file*); |
| |
| // The reloc section. |
| Reloc_section* rel_; |
| // The TLSDESC relocs, if necessary. These must follow the regular |
| // PLT relocs. |
| Reloc_section* tlsdesc_rel_; |
| // The .got section. |
| Output_data_got<64, false>* got_; |
| // The .got.plt section. |
| Output_data_space* got_plt_; |
| // The number of PLT entries. |
| unsigned int count_; |
| // Offset of the reserved TLSDESC_GOT entry when needed. |
| unsigned int tlsdesc_got_offset_; |
| }; |
| |
| // 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 |
| |
| class Target_x86_64 : public Target_freebsd<64, 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, 64, false> Reloc_section; |
| |
| Target_x86_64() |
| : Target_freebsd<64, false>(&x86_64_info), |
| got_(NULL), plt_(NULL), got_plt_(NULL), got_tlsdesc_(NULL), |
| global_offset_table_(NULL), rela_dyn_(NULL), |
| copy_relocs_(elfcpp::R_X86_64_COPY), dynbss_(NULL), |
| got_mod_index_offset_(-1U), tlsdesc_reloc_info_(), |
| tls_base_symbol_defined_(false) |
| { } |
| |
| // 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. |
| inline bool |
| can_check_for_function_pointers() const |
| { return !parameters->options().pie(); } |
| |
| virtual bool |
| can_icf_inline_merge_sections () const |
| { return true; } |
| |
| // 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<64, 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<64, 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<64, 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, |
| elfcpp::Elf_types<64>::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<64, 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*); |
| |
| // Relocate a section during a relocatable link. |
| void |
| relocate_for_relocatable(const Relocate_info<64, false>*, |
| unsigned int sh_type, |
| const unsigned char* prelocs, |
| size_t reloc_count, |
| Output_section* output_section, |
| off_t offset_in_output_section, |
| const Relocatable_relocs*, |
| unsigned char* view, |
| elfcpp::Elf_types<64>::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. |
| Output_data* |
| do_plt_section_for_global(const Symbol*) const |
| { return this->plt_section(); } |
| |
| Output_data* |
| do_plt_section_for_local(const Relobj*, unsigned int) const |
| { return this->plt_section(); } |
| |
| // 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; |
| |
| // Add a new reloc argument, returning the index in the vector. |
| size_t |
| add_tlsdesc_info(Sized_relobj<64, false>* object, unsigned int r_sym) |
| { |
| this->tlsdesc_reloc_info_.push_back(Tlsdesc_info(object, r_sym)); |
| return this->tlsdesc_reloc_info_.size() - 1; |
| } |
| |
| 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<64, false>* object, |
| unsigned int data_shndx, |
| Output_section* output_section, |
| const elfcpp::Rela<64, false>& reloc, unsigned int r_type, |
| const elfcpp::Sym<64, false>& lsym); |
| |
| inline void |
| global(Symbol_table* symtab, Layout* layout, Target_x86_64* target, |
| Sized_relobj<64, false>* object, |
| unsigned int data_shndx, |
| Output_section* output_section, |
| const elfcpp::Rela<64, 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<64, false>* object, |
| unsigned int data_shndx, |
| Output_section* output_section, |
| const elfcpp::Rela<64, false>& reloc, |
| unsigned int r_type, |
| const elfcpp::Sym<64, false>& lsym); |
| |
| inline bool |
| global_reloc_may_be_function_pointer(Symbol_table* symtab, Layout* layout, |
| Target_x86_64* target, |
| Sized_relobj<64, false>* object, |
| unsigned int data_shndx, |
| Output_section* output_section, |
| const elfcpp::Rela<64, false>& reloc, |
| unsigned int r_type, |
| Symbol* gsym); |
| |
| private: |
| static void |
| unsupported_reloc_local(Sized_relobj<64, false>*, unsigned int r_type); |
| |
| static void |
| unsupported_reloc_global(Sized_relobj<64, false>*, unsigned int r_type, |
| Symbol*); |
| |
| void |
| check_non_pic(Relobj*, unsigned int r_type); |
| |
| inline bool |
| possible_function_pointer_reloc(unsigned int r_type); |
| |
| bool |
| reloc_needs_plt_for_ifunc(Sized_relobj<64, 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<64, false>*, Target_x86_64*, Output_section*, |
| size_t relnum, const elfcpp::Rela<64, false>&, |
| unsigned int r_type, const Sized_symbol<64>*, |
| const Symbol_value<64>*, |
| unsigned char*, elfcpp::Elf_types<64>::Elf_Addr, |
| section_size_type); |
| |
| private: |
| // Do a TLS relocation. |
| inline void |
| relocate_tls(const Relocate_info<64, false>*, Target_x86_64*, |
| size_t relnum, const elfcpp::Rela<64, false>&, |
| unsigned int r_type, const Sized_symbol<64>*, |
| const Symbol_value<64>*, |
| unsigned char*, elfcpp::Elf_types<64>::Elf_Addr, |
| section_size_type); |
| |
| // Do a TLS General-Dynamic to Initial-Exec transition. |
| inline void |
| tls_gd_to_ie(const Relocate_info<64, false>*, size_t relnum, |
| Output_segment* tls_segment, |
| const elfcpp::Rela<64, false>&, unsigned int r_type, |
| elfcpp::Elf_types<64>::Elf_Addr value, |
| unsigned char* view, |
| elfcpp::Elf_types<64>::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<64, false>*, size_t relnum, |
| Output_segment* tls_segment, |
| const elfcpp::Rela<64, false>&, unsigned int r_type, |
| elfcpp::Elf_types<64>::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<64, false>*, size_t relnum, |
| Output_segment* tls_segment, |
| const elfcpp::Rela<64, false>&, unsigned int r_type, |
| elfcpp::Elf_types<64>::Elf_Addr value, |
| unsigned char* view, |
| elfcpp::Elf_types<64>::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<64, false>*, size_t relnum, |
| Output_segment* tls_segment, |
| const elfcpp::Rela<64, false>&, unsigned int r_type, |
| elfcpp::Elf_types<64>::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<64, false>*, size_t relnum, |
| Output_segment* tls_segment, |
| const elfcpp::Rela<64, false>&, unsigned int r_type, |
| elfcpp::Elf_types<64>::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<64, false>*, size_t relnum, |
| Output_segment* tls_segment, |
| const elfcpp::Rela<64, false>&, unsigned int r_type, |
| elfcpp::Elf_types<64>::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<64, 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<64, false>* object); |
| |
| // Get the PLT section. |
| Output_data_plt_x86_64* |
| 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; |
| |
| // Add a potential copy relocation. |
| void |
| copy_reloc(Symbol_table* symtab, Layout* layout, |
| Sized_relobj<64, false>* object, |
| unsigned int shndx, Output_section* output_section, |
| Symbol* sym, const elfcpp::Rela<64, false>& reloc) |
| { |
| this->copy_relocs_.copy_reloc(symtab, layout, |
| symtab->get_sized_symbol<64>(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<64, 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<64, 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* plt_; |
| // The GOT PLT section. |
| Output_data_space* got_plt_; |
| // 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_; |
| // Relocs saved to avoid a COPY reloc. |
| Copy_relocs<elfcpp::SHT_RELA, 64, false> copy_relocs_; |
| // Space for variables copied with a COPY reloc. |
| Output_data_space* dynbss_; |
| // 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_; |
| }; |
| |
| const Target::Target_info Target_x86_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 |
| '\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) |
| 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 |
| }; |
| |
| // This is called when a new output section is created. This is where |
| // we handle the SHF_X86_64_LARGE. |
| |
| void |
| Target_x86_64::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. |
| |
| Output_data_got<64, false>* |
| Target_x86_64::got_section(Symbol_table* symtab, Layout* layout) |
| { |
| if (this->got_ == NULL) |
| { |
| gold_assert(symtab != NULL && layout != NULL); |
| |
| 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_, ORDER_RELRO_LAST, |
| 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_, ORDER_NON_RELRO_FIRST, |
| false); |
| |
| // The first three entries are reserved. |
| this->got_plt_->set_current_data_size(3 * 8); |
| |
| // 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 TLSDESC relocations, they get GOT entries in |
| // .got.plt after the jump slot 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_, |
| ORDER_NON_RELRO_FIRST, false); |
| } |
| |
| return this->got_; |
| } |
| |
| // Get the dynamic reloc section, creating it if necessary. |
| |
| Target_x86_64::Reloc_section* |
| Target_x86_64::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_; |
| } |
| |
| // Create the PLT section. The ordinary .got section is an argument, |
| // since we need to refer to the start. We also create our own .got |
| // section just for PLT entries. |
| |
| Output_data_plt_x86_64::Output_data_plt_x86_64(Symbol_table* symtab, |
| Layout* layout, |
| Output_data_got<64, false>* got, |
| Output_data_space* got_plt) |
| : Output_section_data(8), tlsdesc_rel_(NULL), got_(got), got_plt_(got_plt), |
| count_(0), tlsdesc_got_offset_(-1U) |
| { |
| 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); |
| |
| 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->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->rel_, 0, 0, elfcpp::STT_NOTYPE, |
| elfcpp::STB_GLOBAL, elfcpp::STV_HIDDEN, |
| 0, true, true); |
| } |
| } |
| |
| void |
| Output_data_plt_x86_64::do_adjust_output_section(Output_section* os) |
| { |
| os->set_entsize(plt_entry_size); |
| } |
| |
| // Add an entry to the PLT. |
| |
| void |
| Output_data_plt_x86_64::add_entry(Symbol* gsym) |
| { |
| gold_assert(!gsym->has_plt_offset()); |
| |
| // Note that when setting the PLT offset we skip the initial |
| // reserved PLT entry. |
| gsym->set_plt_offset((this->count_ + 1) * plt_entry_size); |
| |
| ++this->count_; |
| |
| section_offset_type got_offset = this->got_plt_->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). |
| this->got_plt_->set_current_data_size(got_offset + 8); |
| |
| // Every PLT entry needs a reloc. |
| if (gsym->type() == elfcpp::STT_GNU_IFUNC |
| && gsym->can_use_relative_reloc(false)) |
| this->rel_->add_symbolless_global_addend(gsym, elfcpp::R_X86_64_IRELATIVE, |
| this->got_plt_, 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); |
| } |
| |
| // 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. |
| |
| unsigned int |
| Output_data_plt_x86_64::add_local_ifunc_entry(Sized_relobj<64, false>* relobj, |
| unsigned int local_sym_index) |
| { |
| unsigned int plt_offset = (this->count_ + 1) * plt_entry_size; |
| ++this->count_; |
| |
| section_offset_type got_offset = this->got_plt_->current_data_size(); |
| |
| // Every PLT entry needs a GOT entry which points back to the PLT |
| // entry. |
| this->got_plt_->set_current_data_size(got_offset + 8); |
| |
| // Every PLT entry needs a reloc. |
| this->rel_->add_symbolless_local_addend(relobj, local_sym_index, |
| elfcpp::R_X86_64_IRELATIVE, |
| this->got_plt_, got_offset, 0); |
| |
| return plt_offset; |
| } |
| |
| // Return where the TLSDESC relocations should go, creating it if |
| // necessary. These follow the JUMP_SLOT relocations. |
| |
| Output_data_plt_x86_64::Reloc_section* |
| Output_data_plt_x86_64::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_; |
| } |
| |
| // Set the final size. |
| void |
| Output_data_plt_x86_64::set_final_data_size() |
| { |
| unsigned int count = this->count_; |
| if (this->has_tlsdesc_entry()) |
| ++count; |
| this->set_data_size((count + 1) * plt_entry_size); |
| } |
| |
| // The first entry in the PLT for an executable. |
| |
| unsigned char Output_data_plt_x86_64::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) |
| }; |
| |
| // Subsequent entries in the PLT for an executable. |
| |
| unsigned char Output_data_plt_x86_64::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 |
| }; |
| |
| // The reserved TLSDESC entry in the PLT for an executable. |
| |
| unsigned char Output_data_plt_x86_64::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 |
| }; |
| |
| // Write out the PLT. This uses the hand-coded instructions above, |
| // and adjusts them as needed. This is specified by the AMD64 ABI. |
| |
| void |
| Output_data_plt_x86_64::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(); |
| const section_size_type got_size = |
| convert_to_section_size_type(this->got_plt_->data_size()); |
| unsigned char* const got_view = of->get_output_view(got_file_offset, |
| got_size); |
| |
| unsigned char* pov = oview; |
| |
| // The base address of the .plt section. |
| elfcpp::Elf_types<64>::Elf_Addr plt_address = this->address(); |
| // The base address of the .got section. |
| elfcpp::Elf_types<64>::Elf_Addr got_base = 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. |
| elfcpp::Elf_types<64>::Elf_Addr got_address = this->got_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))); |
| pov += plt_entry_size; |
| |
| unsigned char* got_pov = got_view; |
| |
| memset(got_pov, 0, 24); |
| got_pov += 24; |
| |
| unsigned int plt_offset = plt_entry_size; |
| unsigned int got_offset = 24; |
| const unsigned int count = this->count_; |
| for (unsigned int plt_index = 0; |
| plt_index < count; |
| ++plt_index, |
| pov += plt_entry_size, |
| got_pov += 8, |
| plt_offset += plt_entry_size, |
| got_offset += 8) |
| { |
| // Set and adjust the PLT entry itself. |
| 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)); |
| |
| // Set the entry in the GOT. |
| elfcpp::Swap<64, false>::writeval(got_pov, plt_address + plt_offset + 6); |
| } |
| |
| if (this->has_tlsdesc_entry()) |
| { |
| // Set and adjust the reserved TLSDESC PLT entry. |
| unsigned int tlsdesc_got_offset = this->get_tlsdesc_got_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))); |
| pov += 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. |
| |
| void |
| Target_x86_64::make_plt_section(Symbol_table* symtab, Layout* layout) |
| { |
| if (this->plt_ == NULL) |
| { |
| // Create the GOT sections first. |
| this->got_section(symtab, layout); |
| |
| this->plt_ = new Output_data_plt_x86_64(symtab, layout, this->got_, |
| this->got_plt_); |
| 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. |
| |
| Target_x86_64::Reloc_section* |
| Target_x86_64::rela_tlsdesc_section(Layout* layout) const |
| { |
| return this->plt_section()->rela_tlsdesc(layout); |
| } |
| |
| // Create a PLT entry for a global symbol. |
| |
| void |
| Target_x86_64::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(gsym); |
| } |
| |
| // Make a PLT entry for a local STT_GNU_IFUNC symbol. |
| |
| void |
| Target_x86_64::make_local_ifunc_plt_entry(Symbol_table* symtab, Layout* layout, |
| Sized_relobj<64, 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(relobj, |
| local_sym_index); |
| relobj->set_local_plt_offset(local_sym_index, plt_offset); |
| } |
| |
| // Return the number of entries in the PLT. |
| |
| unsigned int |
| Target_x86_64::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. |
| |
| unsigned int |
| Target_x86_64::first_plt_entry_offset() const |
| { |
| return Output_data_plt_x86_64::first_plt_entry_offset(); |
| } |
| |
| // Return the size of each PLT entry. |
| |
| unsigned int |
| Target_x86_64::plt_entry_size() const |
| { |
| return Output_data_plt_x86_64::get_plt_entry_size(); |
| } |
| |
| // Define the _TLS_MODULE_BASE_ symbol in the TLS segment. |
| |
| void |
| Target_x86_64::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. |
| |
| void |
| Target_x86_64::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. |
| |
| unsigned int |
| Target_x86_64::got_mod_index_entry(Symbol_table* symtab, Layout* layout, |
| Sized_relobj<64, 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. |
| |
| tls::Tls_optimization |
| Target_x86_64::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. |
| |
| int |
| Target_x86_64::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. |
| |
| void |
| Target_x86_64::Scan::unsupported_reloc_local(Sized_relobj<64, 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. |
| |
| void |
| Target_x86_64::Scan::check_non_pic(Relobj* object, unsigned int r_type) |
| { |
| 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_32: |
| case elfcpp::R_X86_64_PC32: |
| if (this->issued_non_pic_error_) |
| return; |
| gold_assert(parameters->options().output_is_position_independent()); |
| object->error(_("requires dynamic reloc which may overflow at runtime; " |
| "recompile with -fPIC")); |
| 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; " |
| "recompile with -fPIC")); |
| 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. |
| |
| bool |
| Target_x86_64::Scan::reloc_needs_plt_for_ifunc(Sized_relobj<64, 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. |
| |
| inline void |
| Target_x86_64::Scan::local(Symbol_table* symtab, |
| Layout* layout, |
| Target_x86_64* target, |
| Sized_relobj<64, false>* object, |
| unsigned int data_shndx, |
| Output_section* output_section, |
| const elfcpp::Rela<64, false>& reloc, |
| unsigned int r_type, |
| const elfcpp::Sym<64, false>& lsym) |
| { |
| // A local STT_GNU_IFUNC symbol may require a PLT entry. |
| if (lsym.get_st_type() == elfcpp::STT_GNU_IFUNC |
| && this->reloc_needs_plt_for_ifunc(object, r_type)) |
| { |
| unsigned int r_sym = elfcpp::elf_r_sym<64>(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<64>(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()); |
| } |
| 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()) |
| { |
| this->check_non_pic(object, r_type); |
| |
| Reloc_section* rela_dyn = target->rela_dyn_section(layout); |
| unsigned int r_sym = elfcpp::elf_r_sym<64>(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<64>(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 (lsym.get_st_type() == elfcpp::STT_GNU_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); |
| } |
| else |
| { |
| this->check_non_pic(object, r_type); |
| |
| 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::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<64>(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_rela(object, r_sym, |
| shndx, |
| GOT_TYPE_TLS_PAIR, |
| target->rela_dyn_section(layout), |
| elfcpp::R_X86_64_DTPMOD64, 0); |
| } |
| 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<64>(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<64>(reloc.get_r_info()); |
| got->add_local_with_rela(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. |
| |
| void |
| Target_x86_64::Scan::unsupported_reloc_global(Sized_relobj<64, 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. |
| inline bool |
| Target_x86_64::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. |
| |
| inline bool |
| Target_x86_64::Scan::local_reloc_may_be_function_pointer( |
| Symbol_table* , |
| Layout* , |
| Target_x86_64* , |
| Sized_relobj<64, false>* , |
| unsigned int , |
| Output_section* , |
| const elfcpp::Rela<64, false>& , |
| unsigned int r_type, |
| const elfcpp::Sym<64, 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. |
| |
| inline bool |
| Target_x86_64::Scan::global_reloc_may_be_function_pointer( |
| Symbol_table*, |
| Layout* , |
| Target_x86_64* , |
| Sized_relobj<64, false>* , |
| unsigned int , |
| Output_section* , |
| const elfcpp::Rela<64, 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. |
| |
| inline void |
| Target_x86_64::Scan::global(Symbol_table* symtab, |
| Layout* layout, |
| Target_x86_64* target, |
| Sized_relobj<64, false>* object, |
| unsigned int data_shndx, |
| Output_section* output_section, |
| const elfcpp::Rela<64, 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 (r_type == elfcpp::R_X86_64_64 |
| && 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_dyn_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 (r_type == elfcpp::R_X86_64_64 |
| && 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()); |
| } |
| else |
| { |
| this->check_non_pic(object, r_type); |
| 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); |
| 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); |
| if (gsym->is_from_dynobj() |
| || gsym->is_undefined() |
| || gsym->is_preemptible() |
| || (gsym->type() == elfcpp::STT_GNU_IFUNC |
| && parameters->options().output_is_position_independent())) |
| got->add_global_with_rela(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); |
| } |
| } |
| } |
| // 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::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_rela(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_rela(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_rela(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_rela(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_rela(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_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 global symbol %s"), |
| object->name().c_str(), r_type, |
| gsym->demangled_name().c_str()); |
| break; |
| } |
| } |
| |
| void |
| Target_x86_64::gc_process_relocs(Symbol_table* symtab, |
| Layout* layout, |
| Sized_relobj<64, 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<64, false, Target_x86_64, elfcpp::SHT_RELA, |
| Target_x86_64::Scan, |
| Target_x86_64::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. |
| |
| void |
| Target_x86_64::scan_relocs(Symbol_table* symtab, |
| Layout* layout, |
| Sized_relobj<64, 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<64, false, Target_x86_64, elfcpp::SHT_RELA, |
| Target_x86_64::Scan>( |
| symtab, |
| layout, |
| this, |
| object, |
| data_shndx, |
| prelocs, |
| reloc_count, |
| output_section, |
| needs_special_offset_handling, |
| local_symbol_count, |
| plocal_symbols); |
| } |
| |
| // Finalize the sections. |
| |
| void |
| Target_x86_64::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<64>(sym)->set_symsize(data_size); |
| } |
| } |
| |
| // Perform a relocation. |
| |
| inline bool |
| Target_x86_64::Relocate::relocate(const Relocate_info<64, false>* relinfo, |
| Target_x86_64* target, |
| Output_section*, |
| size_t relnum, |
| const elfcpp::Rela<64, false>& rela, |
| unsigned int r_type, |
| const Sized_symbol<64>* gsym, |
| const Symbol_value<64>* psymval, |
| unsigned char* view, |
| elfcpp::Elf_types<64>::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; |
| } |
| } |
| |
| const Sized_relobj<64, false>* object = relinfo->object; |
| |
| // Pick the value to use for symbols defined in the PLT. |
| Symbol_value<64> symval; |
| if (gsym != NULL |
| && gsym->use_plt_offset(Scan::get_reference_flags(r_type))) |
| { |
| symval.set_output_value(target->plt_section()->address() |
| + gsym->plt_offset()); |
| psymval = &symval; |
| } |
| else if (gsym == NULL && psymval->is_ifunc_symbol()) |
| { |
| unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info()); |
| if (object->local_has_plt_offset(r_sym)) |
| { |
| symval.set_output_value(target->plt_section()->address() |
| + object->local_plt_offset(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<64>(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<64, false>::rela64(view, object, psymval, addend); |
| break; |
| |
| case elfcpp::R_X86_64_PC64: |
| Relocate_functions<64, 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<64, 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<64, false>::rela32(view, object, psymval, addend); |
| break; |
| |
| case elfcpp::R_X86_64_PC32: |
| Relocate_functions<64, false>::pcrela32(view, object, psymval, addend, |
| address); |
| break; |
| |
| case elfcpp::R_X86_64_16: |
| Relocate_functions<64, false>::rela16(view, object, psymval, addend); |
| break; |
| |
| case elfcpp::R_X86_64_PC16: |
| Relocate_functions<64, false>::pcrela16(view, object, psymval, addend, |
| address); |
| break; |
| |
| case elfcpp::R_X86_64_8: |
| Relocate_functions<64, false>::rela8(view, object, psymval, addend); |
| break; |
| |
| case elfcpp::R_X86_64_PC8: |
| Relocate_functions<64, 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<64, 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()); |
| elfcpp::Elf_types<64>::Elf_Addr got_address; |
| got_address = target->got_section(NULL, NULL)->address(); |
| Relocate_functions<64, false>::rela64(view, object, psymval, |
| addend - got_address); |
| } |
| |
| case elfcpp::R_X86_64_GOT32: |
| gold_assert(have_got_offset); |
| Relocate_functions<64, false>::rela32(view, got_offset, addend); |
| break; |
| |
| case elfcpp::R_X86_64_GOTPC32: |
| { |
| gold_assert(gsym); |
| elfcpp::Elf_types<64>::Elf_Addr value; |
| value = target->got_plt_section()->address(); |
| Relocate_functions<64, 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<64, false>::rela64(view, got_offset, addend); |
| break; |
| |
| case elfcpp::R_X86_64_GOTPC64: |
| { |
| gold_assert(gsym); |
| elfcpp::Elf_types<64>::Elf_Addr value; |
| value = target->got_plt_section()->address(); |
| Relocate_functions<64, false>::pcrela64(view, value, addend, address); |
| } |
| break; |
| |
| case elfcpp::R_X86_64_GOTOFF64: |
| { |
| elfcpp::Elf_types<64>::Elf_Addr value; |
| value = (psymval->value(object, 0) |
| - target->got_plt_section()->address()); |
| Relocate_functions<64, false>::rela64(view, value, addend); |
| } |
| break; |
| |
| case elfcpp::R_X86_64_GOTPCREL: |
| { |
| gold_assert(have_got_offset); |
| elfcpp::Elf_types<64>::Elf_Addr value; |
| value = target->got_plt_section()->address() + got_offset; |
| Relocate_functions<64, false>::pcrela32(view, value, addend, address); |
| } |
| break; |
| |
| case elfcpp::R_X86_64_GOTPCREL64: |
| { |
| gold_assert(have_got_offset); |
| elfcpp::Elf_types<64>::Elf_Addr value; |
| value = target->got_plt_section()->address() + got_offset; |
| Relocate_functions<64, 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. |
| |
| inline void |
| Target_x86_64::Relocate::relocate_tls(const Relocate_info<64, false>* relinfo, |
| Target_x86_64* target, |
| size_t relnum, |
| const elfcpp::Rela<64, false>& rela, |
| unsigned int r_type, |
| const Sized_symbol<64>* gsym, |
| const Symbol_value<64>* psymval, |
| unsigned char* view, |
| elfcpp::Elf_types<64>::Elf_Addr address, |
| section_size_type view_size) |
| { |
| Output_segment* tls_segment = relinfo->layout->tls_segment(); |
| |
| const Sized_relobj<64, false>* object = relinfo->object; |
| const elfcpp::Elf_Xword addend = rela.get_r_addend(); |
| elfcpp::Shdr<64, false> data_shdr(relinfo->data_shdr); |
| bool is_executable = (data_shdr.get_sh_flags() & elfcpp::SHF_EXECINSTR) != 0; |
| |
| elfcpp::Elf_types<64>::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::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) |
| { |
| gold_assert(tls_segment != NULL); |
| 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<64>(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) |
| { |
| gold_assert(tls_segment != NULL); |
| 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<64, 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) |
| { |
| gold_assert(tls_segment != NULL); |
| 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<64>(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) |
| { |
| gold_assert(tls_segment != NULL); |
| 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<64, 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) |
| { |
| gold_assert(tls_segment != NULL); |
| 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<64, 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) |
| { |
| gold_assert(tls_segment != NULL); |
| value -= tls_segment->memsz(); |
| } |
| Relocate_functions<64, 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) |
| { |
| gold_assert(tls_segment != NULL); |
| value -= tls_segment->memsz(); |
| } |
| Relocate_functions<64, false>::rela64(view, value, addend); |
| break; |
| |
| case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec |
| if (optimized_type == tls::TLSOPT_TO_LE) |
| { |
| gold_assert(tls_segment != NULL); |
| Target_x86_64::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<64>(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<64, 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 |
| value -= tls_segment->memsz(); |
| Relocate_functions<64, false>::rela32(view, value, addend); |
| break; |
| } |
| } |
| |
| // Do a relocation in which we convert a TLS General-Dynamic to an |
| // Initial-Exec. |
| |
| inline void |
| Target_x86_64::Relocate::tls_gd_to_ie(const Relocate_info<64, false>* relinfo, |
| size_t relnum, |
| Output_segment*, |
| const elfcpp::Rela<64, false>& rela, |
| unsigned int, |
| elfcpp::Elf_types<64>::Elf_Addr value, |
| unsigned char* view, |
| elfcpp::Elf_types<64>::Elf_Addr address, |
| section_size_type view_size) |
| { |
| // .byte 0x66; leaq foo@tlsgd(%rip),%rdi; |
| // .word 0x6666; rex64; call __tls_get_addr |
| // ==> movq %fs:0,%rax; addq x@gottpoff(%rip),%rax |
| |
| tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -4); |
| 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\x48\x8d\x3d", 4) == 0)); |
| tls::check_tls(relinfo, relnum, rela.get_r_offset(), |
| (memcmp(view + 4, "\x66\x66\x48\xe8", 4) == 0)); |
| |
| memcpy(view - 4, "\x64\x48\x8b\x04\x25\0\0\0\0\x48\x03\x05\0\0\0\0", 16); |
| |
| const elfcpp::Elf_Xword addend = rela.get_r_addend(); |
| Relocate_functions<64, 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. |
| |
| inline void |
| Target_x86_64::Relocate::tls_gd_to_le(const Relocate_info<64, false>* relinfo, |
| size_t relnum, |
| Output_segment* tls_segment, |
| const elfcpp::Rela<64, false>& rela, |
| unsigned int, |
| elfcpp::Elf_types<64>::Elf_Addr value, |
| unsigned char* view, |
| section_size_type view_size) |
| { |
| // .byte 0x66; leaq foo@tlsgd(%rip),%rdi; |
| // .word 0x6666; rex64; call __tls_get_addr |
| // ==> movq %fs:0,%rax; leaq x@tpoff(%rax),%rax |
| |
| tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -4); |
| 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\x48\x8d\x3d", 4) == 0)); |
| tls::check_tls(relinfo, relnum, rela.get_r_offset(), |
| (memcmp(view + 4, "\x66\x66\x48\xe8", 4) == 0)); |
| |
| memcpy(view - 4, "\x64\x48\x8b\x04\x25\0\0\0\0\x48\x8d\x80\0\0\0\0", 16); |
| |
| value -= tls_segment->memsz(); |
| Relocate_functions<64, 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. |
| |
| inline void |
| Target_x86_64::Relocate::tls_desc_gd_to_ie( |
| const Relocate_info<64, false>* relinfo, |
| size_t relnum, |
| Output_segment*, |
| const elfcpp::Rela<64, false>& rela, |
| unsigned int r_type, |
| elfcpp::Elf_types<64>::Elf_Addr value, |
| unsigned char* view, |
| elfcpp::Elf_types<64>::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<64, 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. |
| |
| inline void |
| Target_x86_64::Relocate::tls_desc_gd_to_le( |
| const Relocate_info<64, false>* relinfo, |
| size_t relnum, |
| Output_segment* tls_segment, |
| const elfcpp::Rela<64, false>& rela, |
| unsigned int r_type, |
| elfcpp::Elf_types<64>::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<64, 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; |
| } |
| } |
| |
| inline void |
| Target_x86_64::Relocate::tls_ld_to_le(const Relocate_info<64, false>* relinfo, |
| size_t relnum, |
| Output_segment*, |
| const elfcpp::Rela<64, false>& rela, |
| unsigned int, |
| elfcpp::Elf_types<64>::Elf_Addr, |
| unsigned char* view, |
| section_size_type view_size) |
| { |
| // leaq foo@tlsld(%rip),%rdi; call __tls_get_addr@plt; |
| // ... leq foo@dtpoff(%rax),%reg |
| // ==> .word 0x6666; .byte 0x66; movq %fs:0,%rax ... 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); |
| |
| memcpy(view - 3, "\x66\x66\x66\x64\x48\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. |
| |
| inline void |
| Target_x86_64::Relocate::tls_ie_to_le(const Relocate_info<64, false>* relinfo, |
| size_t relnum, |
| Output_segment* tls_segment, |
| const elfcpp::Rela<64, false>& rela, |
| unsigned int, |
| elfcpp::Elf_types<64>::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<64, false>::rela32(view, value, 0); |
| } |
| |
| // Relocate section data. |
| |
| void |
| Target_x86_64::relocate_section( |
| const Relocate_info<64, 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, |
| elfcpp::Elf_types<64>::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<64, false, Target_x86_64, elfcpp::SHT_RELA, |
| Target_x86_64::Relocate>( |
| relinfo, |
| this, |
| prelocs, |
| reloc_count, |
| output_section, |
| needs_special_offset_handling, |
| view, |
| address, |
| view_size, |
| reloc_symbol_changes); |
| } |
| |
| // Return the size of a relocation while scanning during a relocatable |
| // link. |
| |
| unsigned int |
| Target_x86_64::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. |
| |
| void |
| Target_x86_64::scan_relocatable_relocs(Symbol_table* symtab, |
| Layout* layout, |
| Sized_relobj<64, 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<64, 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. |
| |
| void |
| Target_x86_64::relocate_for_relocatable( |
| const Relocate_info<64, false>* relinfo, |
| unsigned int sh_type, |
| const unsigned char* prelocs, |
| size_t reloc_count, |
| Output_section* output_section, |
| off_t offset_in_output_section, |
| const Relocatable_relocs* rr, |
| unsigned char* view, |
| elfcpp::Elf_types<64>::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_for_relocatable<64, 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. |
| |
| uint64_t |
| Target_x86_64::do_dynsym_value(const Symbol* gsym) const |
| { |
| gold_assert(gsym->is_from_dynobj() && gsym->has_plt_offset()); |
| return this->plt_section()->address() + gsym->plt_offset(); |
| } |
| |
| // Return a string used to fill a code section with nops to take up |
| // the specified length. |
| |
| std::string |
| Target_x86_64::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, '\0')); |
| } |
| |
| // Nop sequences of various lengths. |
| const char nop1[1] = { 0x90 }; // nop |
| const char nop2[2] = { 0x66, 0x90 }; // xchg %ax %ax |
| const char nop3[3] = { 0x0f, 0x1f, 0x00 }; // nop (%rax) |
| const char nop4[4] = { 0x0f, 0x1f, 0x40, 0x00}; // nop 0(%rax) |
| const char nop5[5] = { 0x0f, 0x1f, 0x44, 0x00, // nop 0(%rax,%rax,1) |
| 0x00 }; |
| const char nop6[6] = { 0x66, 0x0f, 0x1f, 0x44, // nopw 0(%rax,%rax,1) |
| 0x00, 0x00 }; |
| const char nop7[7] = { 0x0f, 0x1f, 0x80, 0x00, // nopl 0L(%rax) |
| 0x00, 0x00, 0x00 }; |
| const char nop8[8] = { 0x0f, 0x1f, 0x84, 0x00, // nopl 0L(%rax,%rax,1) |
| 0x00, 0x00, 0x00, 0x00 }; |
| const char nop9[9] = { 0x66, 0x0f, 0x1f, 0x84, // nopw 0L(%rax,%rax,1) |
| 0x00, 0x00, 0x00, 0x00, |
| 0x00 }; |
| const char nop10[10] = { 0x66, 0x2e, 0x0f, 0x1f, // nopw %cs:0L(%rax,%rax,1) |
| 0x84, 0x00, 0x00, 0x00, |
| 0x00, 0x00 }; |
| const char nop11[11] = { 0x66, 0x66, 0x2e, 0x0f, // data16 |
| 0x1f, 0x84, 0x00, 0x00, // nopw %cs:0L(%rax,%rax,1) |
| 0x00, 0x00, 0x00 }; |
| const char nop12[12] = { 0x66, 0x66, 0x66, 0x2e, // data16; data16 |
| 0x0f, 0x1f, 0x84, 0x00, // nopw %cs:0L(%rax,%rax,1) |
| 0x00, 0x00, 0x00, 0x00 }; |
| const char nop13[13] = { 0x66, 0x66, 0x66, 0x66, // data16; data16; data16 |
| 0x2e, 0x0f, 0x1f, 0x84, // nopw %cs:0L(%rax,%rax,1) |
| 0x00, 0x00, 0x00, 0x00, |
| 0x00 }; |
| const char nop14[14] = { 0x66, 0x66, 0x66, 0x66, // data16; data16; data16 |
| 0x66, 0x2e, 0x0f, 0x1f, // data16 |
| 0x84, 0x00, 0x00, 0x00, // nopw %cs:0L(%rax,%rax,1) |
| 0x00, 0x00 }; |
| const char nop15[15] = { 0x66, 0x66, 0x66, 0x66, // data16; data16; data16 |
| 0x66, 0x66, 0x2e, 0x0f, // data16; data16 |
| 0x1f, 0x84, 0x00, 0x00, // nopw %cs:0L(%rax,%rax,1) |
| 0x00, 0x00, 0x00 }; |
| |
| 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. |
| |
| uint64_t |
| Target_x86_64::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<64>* 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); |
| } |
| |
| // 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. |
| |
| void |
| Target_x86_64::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. |
| |
| class Target_selector_x86_64 : public Target_selector_freebsd |
| { |
| public: |
| Target_selector_x86_64() |
| : Target_selector_freebsd(elfcpp::EM_X86_64, 64, false, "elf64-x86-64", |
| "elf64-x86-64-freebsd") |
| { } |
| |
| Target* |
| do_instantiate_target() |
| { return new Target_x86_64(); } |
| |
| }; |
| |
| Target_selector_x86_64 target_selector_x86_64; |
| |
| } // End anonymous namespace. |