| // i386.cc -- i386 target support for gold. |
| |
| // Copyright (C) 2006-2024 Free Software Foundation, Inc. |
| // Written by Ian Lance Taylor <iant@google.com>. |
| |
| // This file is part of gold. |
| |
| // This program is free software; you can redistribute it and/or modify |
| // it under the terms of the GNU General Public License as published by |
| // the Free Software Foundation; either version 3 of the License, or |
| // (at your option) any later version. |
| |
| // This program is distributed in the hope that it will be useful, |
| // but WITHOUT ANY WARRANTY; without even the implied warranty of |
| // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| // GNU General Public License for more details. |
| |
| // You should have received a copy of the GNU General Public License |
| // along with this program; if not, write to the Free Software |
| // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, |
| // MA 02110-1301, USA. |
| |
| #include "gold.h" |
| |
| #include <cstring> |
| |
| #include "elfcpp.h" |
| #include "dwarf.h" |
| #include "parameters.h" |
| #include "reloc.h" |
| #include "i386.h" |
| #include "object.h" |
| #include "symtab.h" |
| #include "layout.h" |
| #include "output.h" |
| #include "copy-relocs.h" |
| #include "target.h" |
| #include "target-reloc.h" |
| #include "target-select.h" |
| #include "tls.h" |
| #include "freebsd.h" |
| #include "nacl.h" |
| #include "gc.h" |
| |
| namespace |
| { |
| |
| using namespace gold; |
| |
| // A class to handle the .got.plt section. |
| |
| class Output_data_got_plt_i386 : public Output_section_data_build |
| { |
| public: |
| Output_data_got_plt_i386(Layout* layout) |
| : Output_section_data_build(4), |
| layout_(layout) |
| { } |
| |
| protected: |
| // Write out the PLT data. |
| void |
| do_write(Output_file*); |
| |
| // Write to a map file. |
| void |
| do_print_to_mapfile(Mapfile* mapfile) const |
| { mapfile->print_output_data(this, "** GOT PLT"); } |
| |
| private: |
| // A pointer to the Layout class, so that we can find the .dynamic |
| // section when we write out the GOT PLT section. |
| Layout* layout_; |
| }; |
| |
| // A class to handle the PLT data. |
| // This is an abstract base class that handles most of the linker details |
| // but does not know the actual contents of PLT entries. The derived |
| // classes below fill in those details. |
| |
| class Output_data_plt_i386 : public Output_section_data |
| { |
| public: |
| typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, false> Reloc_section; |
| |
| Output_data_plt_i386(Layout*, uint64_t addralign, |
| Output_data_got_plt_i386*, Output_data_space*); |
| |
| // Add an entry to the PLT. |
| void |
| add_entry(Symbol_table*, Layout*, Symbol* gsym); |
| |
| // Add an entry to the PLT for a local STT_GNU_IFUNC symbol. |
| unsigned int |
| add_local_ifunc_entry(Symbol_table*, Layout*, |
| Sized_relobj_file<32, false>* relobj, |
| unsigned int local_sym_index); |
| |
| // Return the .rel.plt section data. |
| Reloc_section* |
| rel_plt() const |
| { return this->rel_; } |
| |
| // Return where the TLS_DESC relocations should go. |
| Reloc_section* |
| rel_tls_desc(Layout*); |
| |
| // Return where the IRELATIVE relocations should go. |
| Reloc_section* |
| rel_irelative(Symbol_table*, Layout*); |
| |
| // Return whether we created a section for IRELATIVE relocations. |
| bool |
| has_irelative_section() const |
| { return this->irelative_rel_ != NULL; } |
| |
| // Return the number of PLT entries. |
| unsigned int |
| entry_count() const |
| { return this->count_ + this->irelative_count_; } |
| |
| // Return the offset of the first non-reserved PLT entry. |
| unsigned int |
| first_plt_entry_offset() |
| { return this->get_plt_entry_size(); } |
| |
| // Return the size of a PLT entry. |
| unsigned int |
| get_plt_entry_size() const |
| { return this->do_get_plt_entry_size(); } |
| |
| // Return the PLT address to use for a global symbol. |
| uint64_t |
| address_for_global(const Symbol*); |
| |
| // Return the PLT address to use for a local symbol. |
| uint64_t |
| address_for_local(const Relobj*, unsigned int symndx); |
| |
| // Add .eh_frame information for the PLT. |
| void |
| add_eh_frame(Layout* layout) |
| { this->do_add_eh_frame(layout); } |
| |
| protected: |
| // Fill the first PLT entry, given the pointer to the PLT section data |
| // and the runtime address of the GOT. |
| void |
| fill_first_plt_entry(unsigned char* pov, |
| elfcpp::Elf_types<32>::Elf_Addr got_address) |
| { this->do_fill_first_plt_entry(pov, got_address); } |
| |
| // Fill a normal PLT entry, given the pointer to the entry's data in the |
| // section, the runtime address of the GOT, the offset into the GOT of |
| // the corresponding slot, the offset into the relocation section of the |
| // corresponding reloc, and the offset of this entry within the whole |
| // PLT. Return the offset from this PLT entry's runtime address that |
| // should be used to compute the initial value of the GOT slot. |
| unsigned int |
| fill_plt_entry(unsigned char* pov, |
| elfcpp::Elf_types<32>::Elf_Addr got_address, |
| unsigned int got_offset, |
| unsigned int plt_offset, |
| unsigned int plt_rel_offset) |
| { |
| return this->do_fill_plt_entry(pov, got_address, got_offset, |
| plt_offset, plt_rel_offset); |
| } |
| |
| virtual unsigned int |
| do_get_plt_entry_size() const = 0; |
| |
| virtual void |
| do_fill_first_plt_entry(unsigned char* pov, |
| elfcpp::Elf_types<32>::Elf_Addr got_address) = 0; |
| |
| virtual unsigned int |
| do_fill_plt_entry(unsigned char* pov, |
| elfcpp::Elf_types<32>::Elf_Addr got_address, |
| unsigned int got_offset, |
| unsigned int plt_offset, |
| unsigned int plt_rel_offset) = 0; |
| |
| virtual void |
| do_add_eh_frame(Layout*) = 0; |
| |
| void |
| do_adjust_output_section(Output_section* os); |
| |
| // Write to a map file. |
| void |
| do_print_to_mapfile(Mapfile* mapfile) const |
| { mapfile->print_output_data(this, _("** PLT")); } |
| |
| // The .eh_frame unwind information for the PLT. |
| // The CIE is common across variants of the PLT format. |
| static const int plt_eh_frame_cie_size = 16; |
| static const unsigned char plt_eh_frame_cie[plt_eh_frame_cie_size]; |
| |
| private: |
| // Set the final size. |
| void |
| set_final_data_size() |
| { |
| this->set_data_size((this->count_ + this->irelative_count_ + 1) |
| * this->get_plt_entry_size()); |
| } |
| |
| // Write out the PLT data. |
| void |
| do_write(Output_file*); |
| |
| // We keep a list of global STT_GNU_IFUNC symbols, each with its |
| // offset in the GOT. |
| struct Global_ifunc |
| { |
| Symbol* sym; |
| unsigned int got_offset; |
| }; |
| |
| // We keep a list of local STT_GNU_IFUNC symbols, each with its |
| // offset in the GOT. |
| struct Local_ifunc |
| { |
| Sized_relobj_file<32, false>* object; |
| unsigned int local_sym_index; |
| unsigned int got_offset; |
| }; |
| |
| // The reloc section. |
| Reloc_section* rel_; |
| // The TLS_DESC relocations, if necessary. These must follow the |
| // regular PLT relocs. |
| Reloc_section* tls_desc_rel_; |
| // The IRELATIVE relocations, if necessary. These must follow the |
| // regular relocatoins and the TLS_DESC relocations. |
| Reloc_section* irelative_rel_; |
| // The .got.plt section. |
| Output_data_got_plt_i386* got_plt_; |
| // The part of the .got.plt section used for IRELATIVE relocs. |
| Output_data_space* got_irelative_; |
| // The number of PLT entries. |
| unsigned int count_; |
| // Number of PLT entries with R_386_IRELATIVE relocs. These follow |
| // the regular PLT entries. |
| unsigned int irelative_count_; |
| // Global STT_GNU_IFUNC symbols. |
| std::vector<Global_ifunc> global_ifuncs_; |
| // Local STT_GNU_IFUNC symbols. |
| std::vector<Local_ifunc> local_ifuncs_; |
| }; |
| |
| // This is an abstract class for the standard PLT layout. |
| // The derived classes below handle the actual PLT contents |
| // for the executable (non-PIC) and shared-library (PIC) cases. |
| // The unwind information is uniform across those two, so it's here. |
| |
| class Output_data_plt_i386_standard : public Output_data_plt_i386 |
| { |
| public: |
| Output_data_plt_i386_standard(Layout* layout, |
| Output_data_got_plt_i386* got_plt, |
| Output_data_space* got_irelative) |
| : Output_data_plt_i386(layout, plt_entry_size, got_plt, got_irelative) |
| { } |
| |
| protected: |
| virtual unsigned int |
| do_get_plt_entry_size() const |
| { return plt_entry_size; } |
| |
| virtual void |
| do_add_eh_frame(Layout* layout) |
| { |
| layout->add_eh_frame_for_plt(this, plt_eh_frame_cie, plt_eh_frame_cie_size, |
| plt_eh_frame_fde, plt_eh_frame_fde_size); |
| } |
| |
| // The size of an entry in the PLT. |
| static const int plt_entry_size = 16; |
| |
| // The .eh_frame unwind information for the PLT. |
| static const int plt_eh_frame_fde_size = 32; |
| static const unsigned char plt_eh_frame_fde[plt_eh_frame_fde_size]; |
| }; |
| |
| // Actually fill the PLT contents for an executable (non-PIC). |
| |
| class Output_data_plt_i386_exec : public Output_data_plt_i386_standard |
| { |
| public: |
| Output_data_plt_i386_exec(Layout* layout, |
| Output_data_got_plt_i386* got_plt, |
| Output_data_space* got_irelative) |
| : Output_data_plt_i386_standard(layout, got_plt, got_irelative) |
| { } |
| |
| protected: |
| virtual void |
| do_fill_first_plt_entry(unsigned char* pov, |
| elfcpp::Elf_types<32>::Elf_Addr got_address); |
| |
| virtual unsigned int |
| do_fill_plt_entry(unsigned char* pov, |
| elfcpp::Elf_types<32>::Elf_Addr got_address, |
| unsigned int got_offset, |
| unsigned int plt_offset, |
| unsigned int plt_rel_offset); |
| |
| private: |
| // The first entry in the PLT for an executable. |
| static const unsigned char first_plt_entry[plt_entry_size]; |
| |
| // Other entries in the PLT for an executable. |
| static const unsigned char plt_entry[plt_entry_size]; |
| }; |
| |
| // Actually fill the PLT contents for a shared library (PIC). |
| |
| class Output_data_plt_i386_dyn : public Output_data_plt_i386_standard |
| { |
| public: |
| Output_data_plt_i386_dyn(Layout* layout, |
| Output_data_got_plt_i386* got_plt, |
| Output_data_space* got_irelative) |
| : Output_data_plt_i386_standard(layout, got_plt, got_irelative) |
| { } |
| |
| protected: |
| virtual void |
| do_fill_first_plt_entry(unsigned char* pov, elfcpp::Elf_types<32>::Elf_Addr); |
| |
| virtual unsigned int |
| do_fill_plt_entry(unsigned char* pov, |
| elfcpp::Elf_types<32>::Elf_Addr, |
| unsigned int got_offset, |
| unsigned int plt_offset, |
| unsigned int plt_rel_offset); |
| |
| private: |
| // The first entry in the PLT for a shared object. |
| static const unsigned char first_plt_entry[plt_entry_size]; |
| |
| // Other entries in the PLT for a shared object. |
| static const unsigned char plt_entry[plt_entry_size]; |
| }; |
| |
| // The i386 target class. |
| // 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_i386 : public Sized_target<32, false> |
| { |
| public: |
| typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, false> Reloc_section; |
| |
| Target_i386(const Target::Target_info* info = &i386_info) |
| : Sized_target<32, false>(info), |
| got_(NULL), plt_(NULL), got_plt_(NULL), got_irelative_(NULL), |
| got_tlsdesc_(NULL), global_offset_table_(NULL), rel_dyn_(NULL), |
| rel_irelative_(NULL), copy_relocs_(elfcpp::R_386_COPY), |
| got_mod_index_offset_(-1U), tls_base_symbol_defined_(false) |
| { } |
| |
| // Process the relocations to determine unreferenced sections for |
| // garbage collection. |
| void |
| gc_process_relocs(Symbol_table* symtab, |
| Layout* layout, |
| Sized_relobj_file<32, false>* object, |
| unsigned int data_shndx, |
| unsigned int sh_type, |
| const unsigned char* prelocs, |
| size_t reloc_count, |
| Output_section* output_section, |
| bool needs_special_offset_handling, |
| size_t local_symbol_count, |
| const unsigned char* plocal_symbols); |
| |
| // Scan the relocations to look for symbol adjustments. |
| void |
| scan_relocs(Symbol_table* symtab, |
| Layout* layout, |
| Sized_relobj_file<32, 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<32, 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<32>::Elf_Addr view_address, |
| section_size_type view_size, |
| const Reloc_symbol_changes*); |
| |
| // Scan the relocs during a relocatable link. |
| void |
| scan_relocatable_relocs(Symbol_table* symtab, |
| Layout* layout, |
| Sized_relobj_file<32, false>* object, |
| unsigned int data_shndx, |
| unsigned int sh_type, |
| const unsigned char* prelocs, |
| size_t reloc_count, |
| Output_section* output_section, |
| bool needs_special_offset_handling, |
| size_t local_symbol_count, |
| const unsigned char* plocal_symbols, |
| Relocatable_relocs*); |
| |
| // Scan the relocs for --emit-relocs. |
| void |
| emit_relocs_scan(Symbol_table* symtab, |
| Layout* layout, |
| Sized_relobj_file<32, false>* object, |
| unsigned int data_shndx, |
| unsigned int sh_type, |
| const unsigned char* prelocs, |
| size_t reloc_count, |
| Output_section* output_section, |
| bool needs_special_offset_handling, |
| size_t local_symbol_count, |
| const unsigned char* plocal_syms, |
| Relocatable_relocs* rr); |
| |
| // Emit relocations for a section. |
| void |
| relocate_relocs(const Relocate_info<32, false>*, |
| unsigned int sh_type, |
| const unsigned char* prelocs, |
| size_t reloc_count, |
| Output_section* output_section, |
| elfcpp::Elf_types<32>::Elf_Off offset_in_output_section, |
| unsigned char* view, |
| elfcpp::Elf_types<32>::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 whether a symbol name implies a local label. The UnixWare |
| // 2.1 cc generates temporary symbols that start with .X, so we |
| // recognize them here. FIXME: do other SVR4 compilers also use .X?. |
| // If so, we should move the .X recognition into |
| // Target::do_is_local_label_name. |
| bool |
| do_is_local_label_name(const char* name) const |
| { |
| if (name[0] == '.' && name[1] == 'X') |
| return true; |
| return Target::do_is_local_label_name(name); |
| } |
| |
| // Return the PLT address to use for a global symbol. |
| uint64_t |
| do_plt_address_for_global(const Symbol* gsym) const |
| { return this->plt_section()->address_for_global(gsym); } |
| |
| uint64_t |
| do_plt_address_for_local(const Relobj* relobj, unsigned int symndx) const |
| { return this->plt_section()->address_for_local(relobj, symndx); } |
| |
| // We can tell whether we take the address of a function. |
| inline bool |
| do_can_check_for_function_pointers() const |
| { return true; } |
| |
| // Return the base for a DW_EH_PE_datarel encoding. |
| uint64_t |
| do_ehframe_datarel_base() const; |
| |
| // Return whether SYM is call to a non-split function. |
| bool |
| do_is_call_to_non_split(const Symbol* sym, const unsigned char*, |
| const unsigned char*, section_size_type) const; |
| |
| // Adjust -fsplit-stack code which calls non-split-stack code. |
| void |
| do_calls_non_split(Relobj* object, unsigned int shndx, |
| section_offset_type fnoffset, section_size_type fnsize, |
| const unsigned char* prelocs, size_t reloc_count, |
| unsigned char* view, section_size_type view_size, |
| std::string* from, std::string* to) const; |
| |
| // Return the size of the GOT section. |
| section_size_type |
| got_size() const |
| { |
| gold_assert(this->got_ != NULL); |
| return this->got_->data_size(); |
| } |
| |
| // Return the number of entries in the GOT. |
| unsigned int |
| got_entry_count() const |
| { |
| if (this->got_ == NULL) |
| return 0; |
| return this->got_size() / 4; |
| } |
| |
| // 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; |
| |
| protected: |
| // Instantiate the plt_ member. |
| // This chooses the right PLT flavor for an executable or a shared object. |
| Output_data_plt_i386* |
| make_data_plt(Layout* layout, |
| Output_data_got_plt_i386* got_plt, |
| Output_data_space* got_irelative, |
| bool dyn) |
| { return this->do_make_data_plt(layout, got_plt, got_irelative, dyn); } |
| |
| virtual Output_data_plt_i386* |
| do_make_data_plt(Layout* layout, |
| Output_data_got_plt_i386* got_plt, |
| Output_data_space* got_irelative, |
| bool dyn) |
| { |
| if (dyn) |
| return new Output_data_plt_i386_dyn(layout, got_plt, got_irelative); |
| else |
| return new Output_data_plt_i386_exec(layout, got_plt, got_irelative); |
| } |
| |
| private: |
| // The class which scans relocations. |
| struct Scan |
| { |
| static inline int |
| |
| get_reference_flags(unsigned int r_type); |
| |
| inline void |
| local(Symbol_table* symtab, Layout* layout, Target_i386* target, |
| Sized_relobj_file<32, false>* object, |
| unsigned int data_shndx, |
| Output_section* output_section, |
| const elfcpp::Rel<32, false>& reloc, unsigned int r_type, |
| const elfcpp::Sym<32, false>& lsym, |
| bool is_discarded); |
| |
| inline void |
| global(Symbol_table* symtab, Layout* layout, Target_i386* target, |
| Sized_relobj_file<32, false>* object, |
| unsigned int data_shndx, |
| Output_section* output_section, |
| const elfcpp::Rel<32, false>& reloc, unsigned int r_type, |
| Symbol* gsym); |
| |
| inline bool |
| local_reloc_may_be_function_pointer(Symbol_table* symtab, Layout* layout, |
| Target_i386* target, |
| Sized_relobj_file<32, false>* object, |
| unsigned int data_shndx, |
| Output_section* output_section, |
| const elfcpp::Rel<32, false>& reloc, |
| unsigned int r_type, |
| const elfcpp::Sym<32, false>& lsym); |
| |
| inline bool |
| global_reloc_may_be_function_pointer(Symbol_table* symtab, Layout* layout, |
| Target_i386* target, |
| Sized_relobj_file<32, false>* object, |
| unsigned int data_shndx, |
| Output_section* output_section, |
| const elfcpp::Rel<32, false>& reloc, |
| unsigned int r_type, |
| Symbol* gsym); |
| |
| inline bool |
| possible_function_pointer_reloc(unsigned int r_type); |
| |
| bool |
| reloc_needs_plt_for_ifunc(Sized_relobj_file<32, false>*, |
| unsigned int r_type); |
| |
| static void |
| unsupported_reloc_local(Sized_relobj_file<32, false>*, unsigned int r_type); |
| |
| static void |
| unsupported_reloc_global(Sized_relobj_file<32, false>*, unsigned int r_type, |
| Symbol*); |
| }; |
| |
| // The class which implements relocation. |
| class Relocate |
| { |
| public: |
| Relocate() |
| : skip_call_tls_get_addr_(false), |
| local_dynamic_type_(LOCAL_DYNAMIC_NONE) |
| { } |
| |
| ~Relocate() |
| { |
| if (this->skip_call_tls_get_addr_) |
| { |
| // FIXME: This needs to specify the location somehow. |
| gold_error(_("missing expected TLS relocation")); |
| } |
| } |
| |
| // Return whether the static relocation needs to be applied. |
| inline bool |
| should_apply_static_reloc(const Sized_symbol<32>* gsym, |
| unsigned int r_type, |
| bool is_32bit, |
| Output_section* output_section); |
| |
| // Do a relocation. Return false if the caller should not issue |
| // any warnings about this relocation. |
| inline bool |
| relocate(const Relocate_info<32, false>*, unsigned int, |
| Target_i386*, Output_section*, size_t, const unsigned char*, |
| const Sized_symbol<32>*, const Symbol_value<32>*, |
| unsigned char*, elfcpp::Elf_types<32>::Elf_Addr, |
| section_size_type); |
| |
| private: |
| // Do a TLS relocation. |
| inline void |
| relocate_tls(const Relocate_info<32, false>*, Target_i386* target, |
| size_t relnum, const elfcpp::Rel<32, false>&, |
| unsigned int r_type, const Sized_symbol<32>*, |
| const Symbol_value<32>*, |
| unsigned char*, elfcpp::Elf_types<32>::Elf_Addr, |
| section_size_type); |
| |
| // Do a TLS General-Dynamic to Initial-Exec transition. |
| inline void |
| tls_gd_to_ie(const Relocate_info<32, false>*, size_t relnum, |
| const elfcpp::Rel<32, false>&, unsigned int r_type, |
| elfcpp::Elf_types<32>::Elf_Addr value, |
| unsigned char* view, |
| section_size_type view_size); |
| |
| // Do a TLS General-Dynamic to Local-Exec transition. |
| inline void |
| tls_gd_to_le(const Relocate_info<32, false>*, size_t relnum, |
| Output_segment* tls_segment, |
| const elfcpp::Rel<32, false>&, unsigned int r_type, |
| elfcpp::Elf_types<32>::Elf_Addr value, |
| unsigned char* view, |
| section_size_type view_size); |
| |
| // Do a TLS_GOTDESC or TLS_DESC_CALL General-Dynamic to Initial-Exec |
| // transition. |
| inline void |
| tls_desc_gd_to_ie(const Relocate_info<32, false>*, size_t relnum, |
| const elfcpp::Rel<32, false>&, unsigned int r_type, |
| elfcpp::Elf_types<32>::Elf_Addr value, |
| unsigned char* view, |
| section_size_type view_size); |
| |
| // Do a TLS_GOTDESC or TLS_DESC_CALL General-Dynamic to Local-Exec |
| // transition. |
| inline void |
| tls_desc_gd_to_le(const Relocate_info<32, false>*, size_t relnum, |
| Output_segment* tls_segment, |
| const elfcpp::Rel<32, false>&, unsigned int r_type, |
| elfcpp::Elf_types<32>::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<32, false>*, size_t relnum, |
| Output_segment* tls_segment, |
| const elfcpp::Rel<32, false>&, unsigned int r_type, |
| elfcpp::Elf_types<32>::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<32, false>*, size_t relnum, |
| Output_segment* tls_segment, |
| const elfcpp::Rel<32, false>&, unsigned int r_type, |
| elfcpp::Elf_types<32>::Elf_Addr value, |
| unsigned char* view, |
| section_size_type view_size); |
| |
| // We need to keep track of which type of local dynamic relocation |
| // we have seen, so that we can optimize R_386_TLS_LDO_32 correctly. |
| enum Local_dynamic_type |
| { |
| LOCAL_DYNAMIC_NONE, |
| LOCAL_DYNAMIC_SUN, |
| LOCAL_DYNAMIC_GNU |
| }; |
| |
| // 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_; |
| // The type of local dynamic relocation we have seen in the section |
| // being relocated, if any. |
| Local_dynamic_type local_dynamic_type_; |
| }; |
| |
| // A class for inquiring about properties of a relocation, |
| // used while scanning relocs during a relocatable link and |
| // garbage collection. |
| class Classify_reloc : |
| public gold::Default_classify_reloc<elfcpp::SHT_REL, 32, false> |
| { |
| public: |
| typedef Reloc_types<elfcpp::SHT_REL, 32, false>::Reloc Reltype; |
| |
| // Return the explicit addend of the relocation (return 0 for SHT_REL). |
| static elfcpp::Elf_types<32>::Elf_Swxword |
| get_r_addend(const Reltype*) |
| { return 0; } |
| |
| // Return the size of the addend of the relocation (only used for SHT_REL). |
| static 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); |
| |
| // Check if relocation against this symbol is a candidate for |
| // conversion from |
| // mov foo@GOT(%reg), %reg |
| // to |
| // lea foo@GOTOFF(%reg), %reg. |
| static bool |
| can_convert_mov_to_lea(const Symbol* gsym) |
| { |
| gold_assert(gsym != NULL); |
| return (gsym->type() != elfcpp::STT_GNU_IFUNC |
| && !gsym->is_undefined () |
| && !gsym->is_from_dynobj() |
| && !gsym->is_preemptible() |
| && (!parameters->options().shared() |
| || (gsym->visibility() != elfcpp::STV_DEFAULT |
| && gsym->visibility() != elfcpp::STV_PROTECTED) |
| || parameters->options().Bsymbolic()) |
| && strcmp(gsym->name(), "_DYNAMIC") != 0); |
| } |
| |
| // Get the GOT section, creating it if necessary. |
| Output_data_got<32, false>* |
| got_section(Symbol_table*, Layout*); |
| |
| // Get the GOT PLT section. |
| Output_data_got_plt_i386* |
| got_plt_section() const |
| { |
| gold_assert(this->got_plt_ != NULL); |
| return this->got_plt_; |
| } |
| |
| // Get the GOT section for TLSDESC entries. |
| Output_data_got<32, false>* |
| got_tlsdesc_section() const |
| { |
| gold_assert(this->got_tlsdesc_ != NULL); |
| return this->got_tlsdesc_; |
| } |
| |
| // Create the PLT section. |
| void |
| make_plt_section(Symbol_table* symtab, Layout* layout); |
| |
| // Create a PLT entry for a global symbol. |
| void |
| make_plt_entry(Symbol_table*, Layout*, Symbol*); |
| |
| // Create a PLT entry for a local STT_GNU_IFUNC symbol. |
| void |
| make_local_ifunc_plt_entry(Symbol_table*, Layout*, |
| Sized_relobj_file<32, 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 a GOT entry for the TLS module index. |
| unsigned int |
| got_mod_index_entry(Symbol_table* symtab, Layout* layout, |
| Sized_relobj_file<32, false>* object); |
| |
| // Get the PLT section. |
| Output_data_plt_i386* |
| plt_section() const |
| { |
| gold_assert(this->plt_ != NULL); |
| return this->plt_; |
| } |
| |
| // Get the dynamic reloc section, creating it if necessary. |
| Reloc_section* |
| rel_dyn_section(Layout*); |
| |
| // Get the section to use for TLS_DESC relocations. |
| Reloc_section* |
| rel_tls_desc_section(Layout*) const; |
| |
| // Get the section to use for IRELATIVE relocations. |
| Reloc_section* |
| rel_irelative_section(Layout*); |
| |
| // Add a potential copy relocation. |
| void |
| copy_reloc(Symbol_table* symtab, Layout* layout, |
| Sized_relobj_file<32, false>* object, |
| unsigned int shndx, Output_section* output_section, |
| Symbol* sym, const elfcpp::Rel<32, false>& reloc) |
| { |
| unsigned int r_type = elfcpp::elf_r_type<32>(reloc.get_r_info()); |
| this->copy_relocs_.copy_reloc(symtab, layout, |
| symtab->get_sized_symbol<32>(sym), |
| object, shndx, output_section, |
| r_type, reloc.get_r_offset(), 0, |
| this->rel_dyn_section(layout)); |
| } |
| |
| // Information about this specific target which we pass to the |
| // general Target structure. |
| static const Target::Target_info i386_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_NOFFSET = 1, // GOT entry for negative TLS offset |
| GOT_TYPE_TLS_OFFSET = 2, // GOT entry for positive TLS offset |
| GOT_TYPE_TLS_PAIR = 3, // GOT entry for TLS module/offset pair |
| GOT_TYPE_TLS_DESC = 4 // GOT entry for TLS_DESC pair |
| }; |
| |
| // The GOT section. |
| Output_data_got<32, false>* got_; |
| // The PLT section. |
| Output_data_plt_i386* plt_; |
| // The GOT PLT section. |
| Output_data_got_plt_i386* got_plt_; |
| // The GOT section for IRELATIVE relocations. |
| Output_data_space* got_irelative_; |
| // The GOT section for TLSDESC relocations. |
| Output_data_got<32, false>* got_tlsdesc_; |
| // The _GLOBAL_OFFSET_TABLE_ symbol. |
| Symbol* global_offset_table_; |
| // The dynamic reloc section. |
| Reloc_section* rel_dyn_; |
| // The section to use for IRELATIVE relocs. |
| Reloc_section* rel_irelative_; |
| // Relocs saved to avoid a COPY reloc. |
| Copy_relocs<elfcpp::SHT_REL, 32, false> copy_relocs_; |
| // Offset of the GOT entry for the TLS module index. |
| unsigned int got_mod_index_offset_; |
| // True if the _TLS_MODULE_BASE_ symbol has been defined. |
| bool tls_base_symbol_defined_; |
| }; |
| |
| const Target::Target_info Target_i386::i386_info = |
| { |
| 32, // size |
| false, // is_big_endian |
| elfcpp::EM_386, // machine_code |
| false, // has_make_symbol |
| false, // has_resolve |
| true, // has_code_fill |
| true, // is_default_stack_executable |
| true, // can_icf_inline_merge_sections |
| '\0', // wrap_char |
| "/usr/lib/libc.so.1", // dynamic_linker |
| 0x08048000, // default_text_segment_address |
| 0x1000, // abi_pagesize (overridable by -z max-page-size) |
| 0x1000, // common_pagesize (overridable by -z common-page-size) |
| false, // isolate_execinstr |
| 0, // rosegment_gap |
| elfcpp::SHN_UNDEF, // small_common_shndx |
| elfcpp::SHN_UNDEF, // large_common_shndx |
| 0, // small_common_section_flags |
| 0, // large_common_section_flags |
| NULL, // attributes_section |
| NULL, // attributes_vendor |
| "_start", // entry_symbol_name |
| 32, // hash_entry_size |
| elfcpp::SHT_PROGBITS, // unwind_section_type |
| }; |
| |
| // Get the GOT section, creating it if necessary. |
| |
| Output_data_got<32, false>* |
| Target_i386::got_section(Symbol_table* symtab, Layout* layout) |
| { |
| if (this->got_ == NULL) |
| { |
| gold_assert(symtab != NULL && layout != NULL); |
| |
| this->got_ = new Output_data_got<32, false>(); |
| |
| // When using -z now, we can treat .got.plt as a relro section. |
| // Without -z now, it is modified after program startup by lazy |
| // PLT relocations. |
| bool is_got_plt_relro = parameters->options().now(); |
| Output_section_order got_order = (is_got_plt_relro |
| ? ORDER_RELRO |
| : ORDER_RELRO_LAST); |
| Output_section_order got_plt_order = (is_got_plt_relro |
| ? ORDER_RELRO |
| : ORDER_NON_RELRO_FIRST); |
| |
| layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS, |
| (elfcpp::SHF_ALLOC |
| | elfcpp::SHF_WRITE), |
| this->got_, got_order, true); |
| |
| this->got_plt_ = new Output_data_got_plt_i386(layout); |
| layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS, |
| (elfcpp::SHF_ALLOC |
| | elfcpp::SHF_WRITE), |
| this->got_plt_, got_plt_order, |
| is_got_plt_relro); |
| |
| // The first three entries are reserved. |
| this->got_plt_->set_current_data_size(3 * 4); |
| |
| if (!is_got_plt_relro) |
| { |
| // Those bytes can go into the relro segment. |
| layout->increase_relro(3 * 4); |
| } |
| |
| // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT. |
| this->global_offset_table_ = |
| symtab->define_in_output_data("_GLOBAL_OFFSET_TABLE_", NULL, |
| Symbol_table::PREDEFINED, |
| this->got_plt_, |
| 0, 0, elfcpp::STT_OBJECT, |
| elfcpp::STB_LOCAL, |
| elfcpp::STV_HIDDEN, 0, |
| false, false); |
| |
| // If there are any IRELATIVE relocations, they get GOT entries |
| // in .got.plt after the jump slot relocations. |
| this->got_irelative_ = new Output_data_space(4, "** GOT IRELATIVE PLT"); |
| layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS, |
| (elfcpp::SHF_ALLOC |
| | elfcpp::SHF_WRITE), |
| this->got_irelative_, |
| got_plt_order, is_got_plt_relro); |
| |
| // If there are any TLSDESC relocations, they get GOT entries in |
| // .got.plt after the jump slot entries. |
| this->got_tlsdesc_ = new Output_data_got<32, false>(); |
| layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS, |
| (elfcpp::SHF_ALLOC |
| | elfcpp::SHF_WRITE), |
| this->got_tlsdesc_, |
| got_plt_order, is_got_plt_relro); |
| } |
| |
| return this->got_; |
| } |
| |
| // Get the dynamic reloc section, creating it if necessary. |
| |
| Target_i386::Reloc_section* |
| Target_i386::rel_dyn_section(Layout* layout) |
| { |
| if (this->rel_dyn_ == NULL) |
| { |
| gold_assert(layout != NULL); |
| this->rel_dyn_ = new Reloc_section(parameters->options().combreloc()); |
| layout->add_output_section_data(".rel.dyn", elfcpp::SHT_REL, |
| elfcpp::SHF_ALLOC, this->rel_dyn_, |
| ORDER_DYNAMIC_RELOCS, false); |
| } |
| return this->rel_dyn_; |
| } |
| |
| // Get the section to use for IRELATIVE relocs, creating it if |
| // necessary. These go in .rel.dyn, but only after all other dynamic |
| // relocations. They need to follow the other dynamic relocations so |
| // that they can refer to global variables initialized by those |
| // relocs. |
| |
| Target_i386::Reloc_section* |
| Target_i386::rel_irelative_section(Layout* layout) |
| { |
| if (this->rel_irelative_ == NULL) |
| { |
| // Make sure we have already create the dynamic reloc section. |
| this->rel_dyn_section(layout); |
| this->rel_irelative_ = new Reloc_section(false); |
| layout->add_output_section_data(".rel.dyn", elfcpp::SHT_REL, |
| elfcpp::SHF_ALLOC, this->rel_irelative_, |
| ORDER_DYNAMIC_RELOCS, false); |
| gold_assert(this->rel_dyn_->output_section() |
| == this->rel_irelative_->output_section()); |
| } |
| return this->rel_irelative_; |
| } |
| |
| // Write the first three reserved words of the .got.plt section. |
| // The remainder of the section is written while writing the PLT |
| // in Output_data_plt_i386::do_write. |
| |
| void |
| Output_data_got_plt_i386::do_write(Output_file* of) |
| { |
| // The first entry in the GOT is the address of the .dynamic section |
| // aka the PT_DYNAMIC segment. The next two entries are reserved. |
| // We saved space for them when we created the section in |
| // Target_i386::got_section. |
| const off_t got_file_offset = this->offset(); |
| gold_assert(this->data_size() >= 12); |
| unsigned char* const got_view = of->get_output_view(got_file_offset, 12); |
| Output_section* dynamic = this->layout_->dynamic_section(); |
| uint32_t dynamic_addr = dynamic == NULL ? 0 : dynamic->address(); |
| elfcpp::Swap<32, false>::writeval(got_view, dynamic_addr); |
| memset(got_view + 4, 0, 8); |
| of->write_output_view(got_file_offset, 12, got_view); |
| } |
| |
| // 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_i386::Output_data_plt_i386(Layout* layout, |
| uint64_t addralign, |
| Output_data_got_plt_i386* got_plt, |
| Output_data_space* got_irelative) |
| : Output_section_data(addralign), |
| tls_desc_rel_(NULL), irelative_rel_(NULL), got_plt_(got_plt), |
| got_irelative_(got_irelative), count_(0), irelative_count_(0), |
| global_ifuncs_(), local_ifuncs_() |
| { |
| this->rel_ = new Reloc_section(false); |
| layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL, |
| elfcpp::SHF_ALLOC, this->rel_, |
| ORDER_DYNAMIC_PLT_RELOCS, false); |
| } |
| |
| void |
| Output_data_plt_i386::do_adjust_output_section(Output_section* os) |
| { |
| // UnixWare sets the entsize of .plt to 4, and so does the old GNU |
| // linker, and so do we. |
| os->set_entsize(4); |
| } |
| |
| // Add an entry to the PLT. |
| |
| void |
| Output_data_plt_i386::add_entry(Symbol_table* symtab, Layout* layout, |
| Symbol* gsym) |
| { |
| gold_assert(!gsym->has_plt_offset()); |
| |
| // Every PLT entry needs a reloc. |
| if (gsym->type() == elfcpp::STT_GNU_IFUNC |
| && gsym->can_use_relative_reloc(false)) |
| { |
| gsym->set_plt_offset(this->irelative_count_ * this->get_plt_entry_size()); |
| ++this->irelative_count_; |
| section_offset_type got_offset = |
| this->got_irelative_->current_data_size(); |
| this->got_irelative_->set_current_data_size(got_offset + 4); |
| Reloc_section* rel = this->rel_irelative(symtab, layout); |
| rel->add_symbolless_global_addend(gsym, elfcpp::R_386_IRELATIVE, |
| this->got_irelative_, got_offset); |
| struct Global_ifunc gi; |
| gi.sym = gsym; |
| gi.got_offset = got_offset; |
| this->global_ifuncs_.push_back(gi); |
| } |
| else |
| { |
| // When setting the PLT offset we skip the initial reserved PLT |
| // entry. |
| gsym->set_plt_offset((this->count_ + 1) * this->get_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 + 4); |
| |
| gsym->set_needs_dynsym_entry(); |
| this->rel_->add_global(gsym, elfcpp::R_386_JUMP_SLOT, this->got_plt_, |
| got_offset); |
| } |
| |
| // Note that we don't need to save the symbol. The contents of the |
| // PLT are independent of which symbols are used. The symbols only |
| // appear in the relocations. |
| } |
| |
| // Add an entry to the PLT for a local STT_GNU_IFUNC symbol. Return |
| // the PLT offset. |
| |
| unsigned int |
| Output_data_plt_i386::add_local_ifunc_entry( |
| Symbol_table* symtab, |
| Layout* layout, |
| Sized_relobj_file<32, false>* relobj, |
| unsigned int local_sym_index) |
| { |
| unsigned int plt_offset = this->irelative_count_ * this->get_plt_entry_size(); |
| ++this->irelative_count_; |
| |
| section_offset_type got_offset = this->got_irelative_->current_data_size(); |
| |
| // Every PLT entry needs a GOT entry which points back to the PLT |
| // entry. |
| this->got_irelative_->set_current_data_size(got_offset + 4); |
| |
| // Every PLT entry needs a reloc. |
| Reloc_section* rel = this->rel_irelative(symtab, layout); |
| rel->add_symbolless_local_addend(relobj, local_sym_index, |
| elfcpp::R_386_IRELATIVE, |
| this->got_irelative_, got_offset); |
| |
| struct Local_ifunc li; |
| li.object = relobj; |
| li.local_sym_index = local_sym_index; |
| li.got_offset = got_offset; |
| this->local_ifuncs_.push_back(li); |
| |
| return plt_offset; |
| } |
| |
| // Return where the TLS_DESC relocations should go, creating it if |
| // necessary. These follow the JUMP_SLOT relocations. |
| |
| Output_data_plt_i386::Reloc_section* |
| Output_data_plt_i386::rel_tls_desc(Layout* layout) |
| { |
| if (this->tls_desc_rel_ == NULL) |
| { |
| this->tls_desc_rel_ = new Reloc_section(false); |
| layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL, |
| elfcpp::SHF_ALLOC, this->tls_desc_rel_, |
| ORDER_DYNAMIC_PLT_RELOCS, false); |
| gold_assert(this->tls_desc_rel_->output_section() |
| == this->rel_->output_section()); |
| } |
| return this->tls_desc_rel_; |
| } |
| |
| // Return where the IRELATIVE relocations should go in the PLT. These |
| // follow the JUMP_SLOT and TLS_DESC relocations. |
| |
| Output_data_plt_i386::Reloc_section* |
| Output_data_plt_i386::rel_irelative(Symbol_table* symtab, Layout* layout) |
| { |
| if (this->irelative_rel_ == NULL) |
| { |
| // Make sure we have a place for the TLS_DESC relocations, in |
| // case we see any later on. |
| this->rel_tls_desc(layout); |
| this->irelative_rel_ = new Reloc_section(false); |
| layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL, |
| elfcpp::SHF_ALLOC, this->irelative_rel_, |
| ORDER_DYNAMIC_PLT_RELOCS, false); |
| gold_assert(this->irelative_rel_->output_section() |
| == this->rel_->output_section()); |
| |
| if (parameters->doing_static_link()) |
| { |
| // A statically linked executable will only have a .rel.plt |
| // section to hold R_386_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("__rel_iplt_start", NULL, |
| Symbol_table::PREDEFINED, |
| this->irelative_rel_, 0, 0, |
| elfcpp::STT_NOTYPE, elfcpp::STB_GLOBAL, |
| elfcpp::STV_HIDDEN, 0, false, true); |
| symtab->define_in_output_data("__rel_iplt_end", NULL, |
| Symbol_table::PREDEFINED, |
| this->irelative_rel_, 0, 0, |
| elfcpp::STT_NOTYPE, elfcpp::STB_GLOBAL, |
| elfcpp::STV_HIDDEN, 0, true, true); |
| } |
| } |
| return this->irelative_rel_; |
| } |
| |
| // Return the PLT address to use for a global symbol. |
| |
| uint64_t |
| Output_data_plt_i386::address_for_global(const Symbol* gsym) |
| { |
| uint64_t offset = 0; |
| if (gsym->type() == elfcpp::STT_GNU_IFUNC |
| && gsym->can_use_relative_reloc(false)) |
| offset = (this->count_ + 1) * this->get_plt_entry_size(); |
| return this->address() + offset + gsym->plt_offset(); |
| } |
| |
| // Return the PLT address to use for a local symbol. These are always |
| // IRELATIVE relocs. |
| |
| uint64_t |
| Output_data_plt_i386::address_for_local(const Relobj* object, |
| unsigned int r_sym) |
| { |
| return (this->address() |
| + (this->count_ + 1) * this->get_plt_entry_size() |
| + object->local_plt_offset(r_sym)); |
| } |
| |
| // The first entry in the PLT for an executable. |
| |
| const unsigned char Output_data_plt_i386_exec::first_plt_entry[plt_entry_size] = |
| { |
| 0xff, 0x35, // pushl contents of memory address |
| 0, 0, 0, 0, // replaced with address of .got + 4 |
| 0xff, 0x25, // jmp indirect |
| 0, 0, 0, 0, // replaced with address of .got + 8 |
| 0, 0, 0, 0 // unused |
| }; |
| |
| void |
| Output_data_plt_i386_exec::do_fill_first_plt_entry( |
| unsigned char* pov, |
| elfcpp::Elf_types<32>::Elf_Addr got_address) |
| { |
| memcpy(pov, first_plt_entry, plt_entry_size); |
| elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_address + 4); |
| elfcpp::Swap<32, false>::writeval(pov + 8, got_address + 8); |
| } |
| |
| // The first entry in the PLT for a shared object. |
| |
| const unsigned char Output_data_plt_i386_dyn::first_plt_entry[plt_entry_size] = |
| { |
| 0xff, 0xb3, 4, 0, 0, 0, // pushl 4(%ebx) |
| 0xff, 0xa3, 8, 0, 0, 0, // jmp *8(%ebx) |
| 0, 0, 0, 0 // unused |
| }; |
| |
| void |
| Output_data_plt_i386_dyn::do_fill_first_plt_entry( |
| unsigned char* pov, |
| elfcpp::Elf_types<32>::Elf_Addr) |
| { |
| memcpy(pov, first_plt_entry, plt_entry_size); |
| } |
| |
| // Subsequent entries in the PLT for an executable. |
| |
| const unsigned char Output_data_plt_i386_exec::plt_entry[plt_entry_size] = |
| { |
| 0xff, 0x25, // jmp indirect |
| 0, 0, 0, 0, // replaced with address of symbol in .got |
| 0x68, // pushl immediate |
| 0, 0, 0, 0, // replaced with offset into relocation table |
| 0xe9, // jmp relative |
| 0, 0, 0, 0 // replaced with offset to start of .plt |
| }; |
| |
| unsigned int |
| Output_data_plt_i386_exec::do_fill_plt_entry( |
| unsigned char* pov, |
| elfcpp::Elf_types<32>::Elf_Addr got_address, |
| unsigned int got_offset, |
| unsigned int plt_offset, |
| unsigned int plt_rel_offset) |
| { |
| memcpy(pov, plt_entry, plt_entry_size); |
| elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, |
| got_address + got_offset); |
| elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_rel_offset); |
| elfcpp::Swap<32, false>::writeval(pov + 12, - (plt_offset + 12 + 4)); |
| return 6; |
| } |
| |
| // Subsequent entries in the PLT for a shared object. |
| |
| const unsigned char Output_data_plt_i386_dyn::plt_entry[plt_entry_size] = |
| { |
| 0xff, 0xa3, // jmp *offset(%ebx) |
| 0, 0, 0, 0, // replaced with offset of symbol in .got |
| 0x68, // pushl immediate |
| 0, 0, 0, 0, // replaced with offset into relocation table |
| 0xe9, // jmp relative |
| 0, 0, 0, 0 // replaced with offset to start of .plt |
| }; |
| |
| unsigned int |
| Output_data_plt_i386_dyn::do_fill_plt_entry(unsigned char* pov, |
| elfcpp::Elf_types<32>::Elf_Addr, |
| unsigned int got_offset, |
| unsigned int plt_offset, |
| unsigned int plt_rel_offset) |
| { |
| memcpy(pov, plt_entry, plt_entry_size); |
| elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_offset); |
| elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_rel_offset); |
| elfcpp::Swap<32, false>::writeval(pov + 12, - (plt_offset + 12 + 4)); |
| return 6; |
| } |
| |
| // The .eh_frame unwind information for the PLT. |
| |
| const unsigned char |
| Output_data_plt_i386::plt_eh_frame_cie[plt_eh_frame_cie_size] = |
| { |
| 1, // CIE version. |
| 'z', // Augmentation: augmentation size included. |
| 'R', // Augmentation: FDE encoding included. |
| '\0', // End of augmentation string. |
| 1, // Code alignment factor. |
| 0x7c, // Data alignment factor. |
| 8, // Return address column. |
| 1, // Augmentation size. |
| (elfcpp::DW_EH_PE_pcrel // FDE encoding. |
| | elfcpp::DW_EH_PE_sdata4), |
| elfcpp::DW_CFA_def_cfa, 4, 4, // DW_CFA_def_cfa: r4 (esp) ofs 4. |
| elfcpp::DW_CFA_offset + 8, 1, // DW_CFA_offset: r8 (eip) at cfa-4. |
| elfcpp::DW_CFA_nop, // Align to 16 bytes. |
| elfcpp::DW_CFA_nop |
| }; |
| |
| const unsigned char |
| Output_data_plt_i386_standard::plt_eh_frame_fde[plt_eh_frame_fde_size] = |
| { |
| 0, 0, 0, 0, // Replaced with offset to .plt. |
| 0, 0, 0, 0, // Replaced with size of .plt. |
| 0, // Augmentation size. |
| elfcpp::DW_CFA_def_cfa_offset, 8, // DW_CFA_def_cfa_offset: 8. |
| elfcpp::DW_CFA_advance_loc + 6, // Advance 6 to __PLT__ + 6. |
| elfcpp::DW_CFA_def_cfa_offset, 12, // DW_CFA_def_cfa_offset: 12. |
| elfcpp::DW_CFA_advance_loc + 10, // Advance 10 to __PLT__ + 16. |
| elfcpp::DW_CFA_def_cfa_expression, // DW_CFA_def_cfa_expression. |
| 11, // Block length. |
| elfcpp::DW_OP_breg4, 4, // Push %esp + 4. |
| elfcpp::DW_OP_breg8, 0, // Push %eip. |
| elfcpp::DW_OP_lit15, // Push 0xf. |
| elfcpp::DW_OP_and, // & (%eip & 0xf). |
| elfcpp::DW_OP_lit11, // Push 0xb. |
| elfcpp::DW_OP_ge, // >= ((%eip & 0xf) >= 0xb) |
| elfcpp::DW_OP_lit2, // Push 2. |
| elfcpp::DW_OP_shl, // << (((%eip & 0xf) >= 0xb) << 2) |
| elfcpp::DW_OP_plus, // + ((((%eip&0xf)>=0xb)<<2)+%esp+4 |
| elfcpp::DW_CFA_nop, // Align to 32 bytes. |
| elfcpp::DW_CFA_nop, |
| elfcpp::DW_CFA_nop, |
| elfcpp::DW_CFA_nop |
| }; |
| |
| // Write out the PLT. This uses the hand-coded instructions above, |
| // and adjusts them as needed. This is all specified by the i386 ELF |
| // Processor Supplement. |
| |
| void |
| Output_data_plt_i386::do_write(Output_file* of) |
| { |
| const off_t offset = this->offset(); |
| const section_size_type oview_size = |
| convert_to_section_size_type(this->data_size()); |
| unsigned char* const oview = of->get_output_view(offset, oview_size); |
| |
| const off_t got_file_offset = this->got_plt_->offset(); |
| gold_assert(parameters->incremental_update() |
| || (got_file_offset + this->got_plt_->data_size() |
| == this->got_irelative_->offset())); |
| const section_size_type got_size = |
| convert_to_section_size_type(this->got_plt_->data_size() |
| + this->got_irelative_->data_size()); |
| |
| unsigned char* const got_view = of->get_output_view(got_file_offset, |
| got_size); |
| |
| unsigned char* pov = oview; |
| |
| elfcpp::Elf_types<32>::Elf_Addr plt_address = this->address(); |
| elfcpp::Elf_types<32>::Elf_Addr got_address = this->got_plt_->address(); |
| |
| this->fill_first_plt_entry(pov, got_address); |
| pov += this->get_plt_entry_size(); |
| |
| // The first three entries in the GOT are reserved, and are written |
| // by Output_data_got_plt_i386::do_write. |
| unsigned char* got_pov = got_view + 12; |
| |
| const int rel_size = elfcpp::Elf_sizes<32>::rel_size; |
| |
| unsigned int plt_offset = this->get_plt_entry_size(); |
| unsigned int plt_rel_offset = 0; |
| unsigned int got_offset = 12; |
| const unsigned int count = this->count_ + this->irelative_count_; |
| for (unsigned int i = 0; |
| i < count; |
| ++i, |
| pov += this->get_plt_entry_size(), |
| got_pov += 4, |
| plt_offset += this->get_plt_entry_size(), |
| plt_rel_offset += rel_size, |
| got_offset += 4) |
| { |
| // Set and adjust the PLT entry itself. |
| unsigned int lazy_offset = this->fill_plt_entry(pov, |
| got_address, |
| got_offset, |
| plt_offset, |
| plt_rel_offset); |
| |
| // Set the entry in the GOT. |
| elfcpp::Swap<32, false>::writeval(got_pov, |
| plt_address + plt_offset + lazy_offset); |
| } |
| |
| // If any STT_GNU_IFUNC symbols have PLT entries, we need to change |
| // the GOT to point to the actual symbol value, rather than point to |
| // the PLT entry. That will let the dynamic linker call the right |
| // function when resolving IRELATIVE relocations. |
| unsigned char* got_irelative_view = got_view + this->got_plt_->data_size(); |
| for (std::vector<Global_ifunc>::const_iterator p = |
| this->global_ifuncs_.begin(); |
| p != this->global_ifuncs_.end(); |
| ++p) |
| { |
| const Sized_symbol<32>* ssym = |
| static_cast<const Sized_symbol<32>*>(p->sym); |
| elfcpp::Swap<32, false>::writeval(got_irelative_view + p->got_offset, |
| ssym->value()); |
| } |
| |
| for (std::vector<Local_ifunc>::const_iterator p = |
| this->local_ifuncs_.begin(); |
| p != this->local_ifuncs_.end(); |
| ++p) |
| { |
| const Symbol_value<32>* psymval = |
| p->object->local_symbol(p->local_sym_index); |
| elfcpp::Swap<32, false>::writeval(got_irelative_view + p->got_offset, |
| psymval->value(p->object, 0)); |
| } |
| |
| 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_i386::make_plt_section(Symbol_table* symtab, Layout* layout) |
| { |
| if (this->plt_ == NULL) |
| { |
| // Create the GOT sections first. |
| this->got_section(symtab, layout); |
| |
| const bool dyn = parameters->options().output_is_position_independent(); |
| this->plt_ = this->make_data_plt(layout, |
| this->got_plt_, |
| this->got_irelative_, |
| dyn); |
| |
| // Add unwind information if requested. |
| if (parameters->options().ld_generated_unwind_info()) |
| this->plt_->add_eh_frame(layout); |
| |
| layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS, |
| (elfcpp::SHF_ALLOC |
| | elfcpp::SHF_EXECINSTR), |
| this->plt_, ORDER_PLT, false); |
| |
| // Make the sh_info field of .rel.plt point to .plt. |
| Output_section* rel_plt_os = this->plt_->rel_plt()->output_section(); |
| rel_plt_os->set_info_section(this->plt_->output_section()); |
| } |
| } |
| |
| // Create a PLT entry for a global symbol. |
| |
| void |
| Target_i386::make_plt_entry(Symbol_table* symtab, Layout* layout, Symbol* gsym) |
| { |
| if (gsym->has_plt_offset()) |
| return; |
| if (this->plt_ == NULL) |
| this->make_plt_section(symtab, layout); |
| this->plt_->add_entry(symtab, layout, gsym); |
| } |
| |
| // Make a PLT entry for a local STT_GNU_IFUNC symbol. |
| |
| void |
| Target_i386::make_local_ifunc_plt_entry(Symbol_table* symtab, Layout* layout, |
| Sized_relobj_file<32, false>* relobj, |
| unsigned int local_sym_index) |
| { |
| if (relobj->local_has_plt_offset(local_sym_index)) |
| return; |
| if (this->plt_ == NULL) |
| this->make_plt_section(symtab, layout); |
| unsigned int plt_offset = this->plt_->add_local_ifunc_entry(symtab, layout, |
| relobj, |
| local_sym_index); |
| relobj->set_local_plt_offset(local_sym_index, plt_offset); |
| } |
| |
| // Return the number of entries in the PLT. |
| |
| unsigned int |
| Target_i386::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_i386::first_plt_entry_offset() const |
| { |
| if (this->plt_ == NULL) |
| return 0; |
| return this->plt_->first_plt_entry_offset(); |
| } |
| |
| // Return the size of each PLT entry. |
| |
| unsigned int |
| Target_i386::plt_entry_size() const |
| { |
| if (this->plt_ == NULL) |
| return 0; |
| return this->plt_->get_plt_entry_size(); |
| } |
| |
| // Get the section to use for TLS_DESC relocations. |
| |
| Target_i386::Reloc_section* |
| Target_i386::rel_tls_desc_section(Layout* layout) const |
| { |
| return this->plt_section()->rel_tls_desc(layout); |
| } |
| |
| // Define the _TLS_MODULE_BASE_ symbol in the TLS segment. |
| |
| void |
| Target_i386::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 a GOT entry for the TLS module index. |
| |
| unsigned int |
| Target_i386::got_mod_index_entry(Symbol_table* symtab, Layout* layout, |
| Sized_relobj_file<32, false>* object) |
| { |
| if (this->got_mod_index_offset_ == -1U) |
| { |
| gold_assert(symtab != NULL && layout != NULL && object != NULL); |
| Reloc_section* rel_dyn = this->rel_dyn_section(layout); |
| Output_data_got<32, false>* got = this->got_section(symtab, layout); |
| unsigned int got_offset = got->add_constant(0); |
| rel_dyn->add_local(object, 0, elfcpp::R_386_TLS_DTPMOD32, got, |
| got_offset); |
| 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_i386::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_386_TLS_GD: |
| case elfcpp::R_386_TLS_GOTDESC: |
| case elfcpp::R_386_TLS_DESC_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_386_TLS_LDM: |
| // 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_386_TLS_LDO_32: |
| // Another type of Local-Dynamic relocation. |
| return tls::TLSOPT_TO_LE; |
| |
| case elfcpp::R_386_TLS_IE: |
| case elfcpp::R_386_TLS_GOTIE: |
| case elfcpp::R_386_TLS_IE_32: |
| // 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_386_TLS_LE: |
| case elfcpp::R_386_TLS_LE_32: |
| // 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_i386::Scan::get_reference_flags(unsigned int r_type) |
| { |
| switch (r_type) |
| { |
| case elfcpp::R_386_NONE: |
| case elfcpp::R_386_GNU_VTINHERIT: |
| case elfcpp::R_386_GNU_VTENTRY: |
| case elfcpp::R_386_GOTPC: |
| // No symbol reference. |
| return 0; |
| |
| case elfcpp::R_386_32: |
| case elfcpp::R_386_16: |
| case elfcpp::R_386_8: |
| return Symbol::ABSOLUTE_REF; |
| |
| case elfcpp::R_386_PC32: |
| case elfcpp::R_386_PC16: |
| case elfcpp::R_386_PC8: |
| case elfcpp::R_386_GOTOFF: |
| return Symbol::RELATIVE_REF; |
| |
| case elfcpp::R_386_PLT32: |
| return Symbol::FUNCTION_CALL | Symbol::RELATIVE_REF; |
| |
| case elfcpp::R_386_GOT32: |
| case elfcpp::R_386_GOT32X: |
| // Absolute in GOT. |
| return Symbol::ABSOLUTE_REF; |
| |
| case elfcpp::R_386_TLS_GD: // Global-dynamic |
| case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url) |
| case elfcpp::R_386_TLS_DESC_CALL: |
| case elfcpp::R_386_TLS_LDM: // Local-dynamic |
| case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic |
| case elfcpp::R_386_TLS_IE: // Initial-exec |
| case elfcpp::R_386_TLS_IE_32: |
| case elfcpp::R_386_TLS_GOTIE: |
| case elfcpp::R_386_TLS_LE: // Local-exec |
| case elfcpp::R_386_TLS_LE_32: |
| return Symbol::TLS_REF; |
| |
| case elfcpp::R_386_COPY: |
| case elfcpp::R_386_GLOB_DAT: |
| case elfcpp::R_386_JUMP_SLOT: |
| case elfcpp::R_386_RELATIVE: |
| case elfcpp::R_386_IRELATIVE: |
| case elfcpp::R_386_TLS_TPOFF: |
| case elfcpp::R_386_TLS_DTPMOD32: |
| case elfcpp::R_386_TLS_DTPOFF32: |
| case elfcpp::R_386_TLS_TPOFF32: |
| case elfcpp::R_386_TLS_DESC: |
| case elfcpp::R_386_32PLT: |
| case elfcpp::R_386_TLS_GD_32: |
| case elfcpp::R_386_TLS_GD_PUSH: |
| case elfcpp::R_386_TLS_GD_CALL: |
| case elfcpp::R_386_TLS_GD_POP: |
| case elfcpp::R_386_TLS_LDM_32: |
| case elfcpp::R_386_TLS_LDM_PUSH: |
| case elfcpp::R_386_TLS_LDM_CALL: |
| case elfcpp::R_386_TLS_LDM_POP: |
| case elfcpp::R_386_USED_BY_INTEL_200: |
| default: |
| // Not expected. We will give an error later. |
| return 0; |
| } |
| } |
| |
| // Report an unsupported relocation against a local symbol. |
| |
| void |
| Target_i386::Scan::unsupported_reloc_local(Sized_relobj_file<32, false>* object, |
| unsigned int r_type) |
| { |
| gold_error(_("%s: unsupported reloc %u against local symbol"), |
| object->name().c_str(), r_type); |
| } |
| |
| // Return whether we need to make a PLT entry for a relocation of a |
| // given type against a STT_GNU_IFUNC symbol. |
| |
| bool |
| Target_i386::Scan::reloc_needs_plt_for_ifunc( |
| Sized_relobj_file<32, 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_i386::Scan::local(Symbol_table* symtab, |
| Layout* layout, |
| Target_i386* target, |
| Sized_relobj_file<32, false>* object, |
| unsigned int data_shndx, |
| Output_section* output_section, |
| const elfcpp::Rel<32, false>& reloc, |
| unsigned int r_type, |
| const elfcpp::Sym<32, false>& lsym, |
| bool is_discarded) |
| { |
| if (is_discarded) |
| return; |
| |
| // 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<32>(reloc.get_r_info()); |
| target->make_local_ifunc_plt_entry(symtab, layout, object, r_sym); |
| } |
| |
| switch (r_type) |
| { |
| case elfcpp::R_386_NONE: |
| case elfcpp::R_386_GNU_VTINHERIT: |
| case elfcpp::R_386_GNU_VTENTRY: |
| break; |
| |
| case elfcpp::R_386_32: |
| // 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_386_RELATIVE relocation so the dynamic loader can |
| // relocate it easily. |
| if (parameters->options().output_is_position_independent()) |
| { |
| Reloc_section* rel_dyn = target->rel_dyn_section(layout); |
| unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info()); |
| rel_dyn->add_local_relative(object, r_sym, elfcpp::R_386_RELATIVE, |
| output_section, data_shndx, |
| reloc.get_r_offset()); |
| } |
| break; |
| |
| case elfcpp::R_386_16: |
| case elfcpp::R_386_8: |
| // If building a shared library (or a position-independent |
| // executable), we need to create a dynamic relocation for |
| // this location. Because the addend needs to remain in the |
| // data section, we need to be careful not to apply this |
| // relocation statically. |
| if (parameters->options().output_is_position_independent()) |
| { |
| Reloc_section* rel_dyn = target->rel_dyn_section(layout); |
| unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info()); |
| if (lsym.get_st_type() != elfcpp::STT_SECTION) |
| rel_dyn->add_local(object, r_sym, r_type, output_section, |
| data_shndx, reloc.get_r_offset()); |
| 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 |
| rel_dyn->add_local_section(object, shndx, |
| r_type, output_section, |
| data_shndx, reloc.get_r_offset()); |
| } |
| } |
| break; |
| |
| case elfcpp::R_386_PC32: |
| case elfcpp::R_386_PC16: |
| case elfcpp::R_386_PC8: |
| break; |
| |
| case elfcpp::R_386_PLT32: |
| // Since we know this is a local symbol, we can handle this as a |
| // PC32 reloc. |
| break; |
| |
| case elfcpp::R_386_GOTOFF: |
| case elfcpp::R_386_GOTPC: |
| // We need a GOT section. |
| target->got_section(symtab, layout); |
| break; |
| |
| case elfcpp::R_386_GOT32: |
| case elfcpp::R_386_GOT32X: |
| { |
| // We need GOT section. |
| Output_data_got<32, false>* got = target->got_section(symtab, layout); |
| |
| // If the relocation symbol isn't IFUNC, |
| // and is local, then we will convert |
| // mov foo@GOT(%reg), %reg |
| // to |
| // lea foo@GOTOFF(%reg), %reg |
| // in Relocate::relocate. |
| if (reloc.get_r_offset() >= 2 |
| && lsym.get_st_type() != elfcpp::STT_GNU_IFUNC) |
| { |
| section_size_type stype; |
| const unsigned char* view = object->section_contents(data_shndx, |
| &stype, true); |
| if (view[reloc.get_r_offset() - 2] == 0x8b) |
| break; |
| } |
| |
| // Otherwise, the symbol requires a GOT entry. |
| unsigned int r_sym = elfcpp::elf_r_sym<32>(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 RELATIVE relocation for this symbol's GOT entry. |
| if (parameters->options().output_is_position_independent()) |
| { |
| Reloc_section* rel_dyn = target->rel_dyn_section(layout); |
| unsigned int got_offset = |
| object->local_got_offset(r_sym, GOT_TYPE_STANDARD); |
| rel_dyn->add_local_relative(object, r_sym, |
| elfcpp::R_386_RELATIVE, |
| got, got_offset); |
| } |
| } |
| } |
| break; |
| |
| // These are relocations which should only be seen by the |
| // dynamic linker, and should never be seen here. |
| case elfcpp::R_386_COPY: |
| case elfcpp::R_386_GLOB_DAT: |
| case elfcpp::R_386_JUMP_SLOT: |
| case elfcpp::R_386_RELATIVE: |
| case elfcpp::R_386_IRELATIVE: |
| case elfcpp::R_386_TLS_TPOFF: |
| case elfcpp::R_386_TLS_DTPMOD32: |
| case elfcpp::R_386_TLS_DTPOFF32: |
| case elfcpp::R_386_TLS_TPOFF32: |
| case elfcpp::R_386_TLS_DESC: |
| 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_386_TLS_GD: // Global-dynamic |
| case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url) |
| case elfcpp::R_386_TLS_DESC_CALL: |
| case elfcpp::R_386_TLS_LDM: // Local-dynamic |
| case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic |
| case elfcpp::R_386_TLS_IE: // Initial-exec |
| case elfcpp::R_386_TLS_IE_32: |
| case elfcpp::R_386_TLS_GOTIE: |
| case elfcpp::R_386_TLS_LE: // Local-exec |
| case elfcpp::R_386_TLS_LE_32: |
| { |
| bool output_is_shared = parameters->options().shared(); |
| const tls::Tls_optimization optimized_type |
| = Target_i386::optimize_tls_reloc(!output_is_shared, r_type); |
| switch (r_type) |
| { |
| case elfcpp::R_386_TLS_GD: // Global-dynamic |
| if (optimized_type == tls::TLSOPT_NONE) |
| { |
| // Create a pair of GOT entries for the module index and |
| // dtv-relative offset. |
| Output_data_got<32, false>* got |
| = target->got_section(symtab, layout); |
| unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info()); |
| unsigned int shndx = lsym.get_st_shndx(); |
| bool is_ordinary; |
| shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary); |
| if (!is_ordinary) |
| object->error(_("local symbol %u has bad shndx %u"), |
| r_sym, shndx); |
| else |
| got->add_local_pair_with_rel(object, r_sym, shndx, |
| GOT_TYPE_TLS_PAIR, |
| target->rel_dyn_section(layout), |
| elfcpp::R_386_TLS_DTPMOD32); |
| } |
| else if (optimized_type != tls::TLSOPT_TO_LE) |
| unsupported_reloc_local(object, r_type); |
| break; |
| |
| case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva) |
| target->define_tls_base_symbol(symtab, layout); |
| if (optimized_type == tls::TLSOPT_NONE) |
| { |
| // Create a double GOT entry with an R_386_TLS_DESC |
| // reloc. The R_386_TLS_DESC 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<32, false>* got = target->got_tlsdesc_section(); |
| unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info()); |
| if (!object->local_has_got_offset(r_sym, GOT_TYPE_TLS_DESC)) |
| { |
| unsigned int got_offset = got->add_constant(0); |
| // The local symbol value is stored in the second |
| // GOT entry. |
| got->add_local(object, r_sym, GOT_TYPE_TLS_DESC); |
| // That set the GOT offset of the local symbol to |
| // point to the second entry, but we want it to |
| // point to the first. |
| object->set_local_got_offset(r_sym, GOT_TYPE_TLS_DESC, |
| got_offset); |
| Reloc_section* rt = target->rel_tls_desc_section(layout); |
| rt->add_absolute(elfcpp::R_386_TLS_DESC, got, got_offset); |
| } |
| } |
| else if (optimized_type != tls::TLSOPT_TO_LE) |
| unsupported_reloc_local(object, r_type); |
| break; |
| |
| case elfcpp::R_386_TLS_DESC_CALL: |
| break; |
| |
| case elfcpp::R_386_TLS_LDM: // 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_386_TLS_LDO_32: // Alternate local-dynamic |
| break; |
| |
| case elfcpp::R_386_TLS_IE: // Initial-exec |
| case elfcpp::R_386_TLS_IE_32: |
| case elfcpp::R_386_TLS_GOTIE: |
| layout->set_has_static_tls(); |
| if (optimized_type == tls::TLSOPT_NONE) |
| { |
| // For the R_386_TLS_IE relocation, we need to create a |
| // dynamic relocation when building a shared library. |
| if (r_type == elfcpp::R_386_TLS_IE |
| && parameters->options().shared()) |
| { |
| Reloc_section* rel_dyn = target->rel_dyn_section(layout); |
| unsigned int r_sym |
| = elfcpp::elf_r_sym<32>(reloc.get_r_info()); |
| rel_dyn->add_local_relative(object, r_sym, |
| elfcpp::R_386_RELATIVE, |
| output_section, data_shndx, |
| reloc.get_r_offset()); |
| } |
| // Create a GOT entry for the tp-relative offset. |
| Output_data_got<32, false>* got |
| = target->got_section(symtab, layout); |
| unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info()); |
| unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_IE_32 |
| ? elfcpp::R_386_TLS_TPOFF32 |
| : elfcpp::R_386_TLS_TPOFF); |
| unsigned int got_type = (r_type == elfcpp::R_386_TLS_IE_32 |
| ? GOT_TYPE_TLS_OFFSET |
| : GOT_TYPE_TLS_NOFFSET); |
| got->add_local_with_rel(object, r_sym, got_type, |
| target->rel_dyn_section(layout), |
| dyn_r_type); |
| } |
| else if (optimized_type != tls::TLSOPT_TO_LE) |
| unsupported_reloc_local(object, r_type); |
| break; |
| |
| case elfcpp::R_386_TLS_LE: // Local-exec |
| case elfcpp::R_386_TLS_LE_32: |
| layout->set_has_static_tls(); |
| if (output_is_shared) |
| { |
| // We need to create a dynamic relocation. |
| gold_assert(lsym.get_st_type() != elfcpp::STT_SECTION); |
| unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info()); |
| unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_LE_32 |
| ? elfcpp::R_386_TLS_TPOFF32 |
| : elfcpp::R_386_TLS_TPOFF); |
| Reloc_section* rel_dyn = target->rel_dyn_section(layout); |
| rel_dyn->add_local(object, r_sym, dyn_r_type, output_section, |
| data_shndx, reloc.get_r_offset()); |
| } |
| break; |
| |
| default: |
| gold_unreachable(); |
| } |
| } |
| break; |
| |
| case elfcpp::R_386_32PLT: |
| case elfcpp::R_386_TLS_GD_32: |
| case elfcpp::R_386_TLS_GD_PUSH: |
| case elfcpp::R_386_TLS_GD_CALL: |
| case elfcpp::R_386_TLS_GD_POP: |
| case elfcpp::R_386_TLS_LDM_32: |
| case elfcpp::R_386_TLS_LDM_PUSH: |
| case elfcpp::R_386_TLS_LDM_CALL: |
| case elfcpp::R_386_TLS_LDM_POP: |
| case elfcpp::R_386_USED_BY_INTEL_200: |
| default: |
| unsupported_reloc_local(object, r_type); |
| break; |
| } |
| } |
| |
| // Report an unsupported relocation against a global symbol. |
| |
| void |
| Target_i386::Scan::unsupported_reloc_global( |
| Sized_relobj_file<32, 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()); |
| } |
| |
| inline bool |
| Target_i386::Scan::possible_function_pointer_reloc(unsigned int r_type) |
| { |
| switch (r_type) |
| { |
| case elfcpp::R_386_32: |
| case elfcpp::R_386_16: |
| case elfcpp::R_386_8: |
| case elfcpp::R_386_GOTOFF: |
| case elfcpp::R_386_GOT32: |
| case elfcpp::R_386_GOT32X: |
| { |
| return true; |
| } |
| default: |
| return false; |
| } |
| return false; |
| } |
| |
| inline bool |
| Target_i386::Scan::local_reloc_may_be_function_pointer( |
| Symbol_table* , |
| Layout* , |
| Target_i386* , |
| Sized_relobj_file<32, false>* , |
| unsigned int , |
| Output_section* , |
| const elfcpp::Rel<32, false>& , |
| unsigned int r_type, |
| const elfcpp::Sym<32, false>&) |
| { |
| return possible_function_pointer_reloc(r_type); |
| } |
| |
| inline bool |
| Target_i386::Scan::global_reloc_may_be_function_pointer( |
| Symbol_table* , |
| Layout* , |
| Target_i386* , |
| Sized_relobj_file<32, false>* , |
| unsigned int , |
| Output_section* , |
| const elfcpp::Rel<32, false>& , |
| unsigned int r_type, |
| Symbol*) |
| { |
| return possible_function_pointer_reloc(r_type); |
| } |
| |
| // Scan a relocation for a global symbol. |
| |
| inline void |
| Target_i386::Scan::global(Symbol_table* symtab, |
| Layout* layout, |
| Target_i386* target, |
| Sized_relobj_file<32, false>* object, |
| unsigned int data_shndx, |
| Output_section* output_section, |
| const elfcpp::Rel<32, 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_386_NONE: |
| case elfcpp::R_386_GNU_VTINHERIT: |
| case elfcpp::R_386_GNU_VTENTRY: |
| break; |
| |
| case elfcpp::R_386_32: |
| case elfcpp::R_386_16: |
| case elfcpp::R_386_8: |
| { |
| // Make a PLT entry if necessary. |
| if (gsym->needs_plt_entry()) |
| { |
| target->make_plt_entry(symtab, layout, gsym); |
| // Since this is not a PC-relative relocation, we may be |
| // taking the address of a function. In that case we need to |
| // set the entry in the dynamic symbol table to the address of |
| // the PLT entry. |
| if (gsym->is_from_dynobj() && !parameters->options().shared()) |
| gsym->set_needs_dynsym_value(); |
| } |
| // Make a dynamic relocation if necessary. |
| if (gsym->needs_dynamic_reloc(Scan::get_reference_flags(r_type))) |
| { |
| if (!parameters->options().output_is_position_independent() |
| && gsym->may_need_copy_reloc()) |
| { |
| target->copy_reloc(symtab, layout, object, |
| data_shndx, output_section, gsym, reloc); |
| } |
| else if (r_type == elfcpp::R_386_32 |
| && gsym->type() == elfcpp::STT_GNU_IFUNC |
| && gsym->can_use_relative_reloc(false) |
| && !gsym->is_from_dynobj() |
| && !gsym->is_undefined() |
| && !gsym->is_preemptible()) |
| { |
| // Use an IRELATIVE reloc for a locally defined |
| // STT_GNU_IFUNC symbol. This makes a function |
| // address in a PIE executable match the address in a |
| // shared library that it links against. |
| Reloc_section* rel_dyn = target->rel_irelative_section(layout); |
| rel_dyn->add_symbolless_global_addend(gsym, |
| elfcpp::R_386_IRELATIVE, |
| output_section, |
| object, data_shndx, |
| reloc.get_r_offset()); |
| } |
| else if (r_type == elfcpp::R_386_32 |
| && gsym->can_use_relative_reloc(false)) |
| { |
| Reloc_section* rel_dyn = target->rel_dyn_section(layout); |
| rel_dyn->add_global_relative(gsym, elfcpp::R_386_RELATIVE, |
| output_section, object, |
| data_shndx, reloc.get_r_offset()); |
| } |
| else |
| { |
| Reloc_section* rel_dyn = target->rel_dyn_section(layout); |
| rel_dyn->add_global(gsym, r_type, output_section, object, |
| data_shndx, reloc.get_r_offset()); |
| } |
| } |
| } |
| break; |
| |
| case elfcpp::R_386_PC32: |
| case elfcpp::R_386_PC16: |
| case elfcpp::R_386_PC8: |
| { |
| // Make a PLT entry if necessary. |
| if (gsym->needs_plt_entry()) |
| { |
| // These relocations are used for function calls only in |
| // non-PIC code. For a 32-bit relocation in a shared library, |
| // we'll need a text relocation anyway, so we can skip the |
| // PLT entry and let the dynamic linker bind the call directly |
| // to the target. For smaller relocations, we should use a |
| // PLT entry to ensure that the call can reach. |
| if (!parameters->options().shared() |
| || r_type != elfcpp::R_386_PC32) |
| target->make_plt_entry(symtab, layout, gsym); |
| } |
| // Make a dynamic relocation if necessary. |
| if (gsym->needs_dynamic_reloc(Scan::get_reference_flags(r_type))) |
| { |
| if (parameters->options().output_is_executable() |
| && gsym->may_need_copy_reloc()) |
| { |
| target->copy_reloc(symtab, layout, object, |
| data_shndx, output_section, gsym, reloc); |
| } |
| else |
| { |
| Reloc_section* rel_dyn = target->rel_dyn_section(layout); |
| rel_dyn->add_global(gsym, r_type, output_section, object, |
| data_shndx, reloc.get_r_offset()); |
| } |
| } |
| } |
| break; |
| |
| case elfcpp::R_386_GOT32: |
| case elfcpp::R_386_GOT32X: |
| { |
| // The symbol requires a GOT section. |
| Output_data_got<32, false>* got = target->got_section(symtab, layout); |
| |
| // If we convert this from |
| // mov foo@GOT(%reg), %reg |
| // to |
| // lea foo@GOTOFF(%reg), %reg |
| // in Relocate::relocate, then there is nothing to do here. |
| if (reloc.get_r_offset() >= 2 |
| && Target_i386::can_convert_mov_to_lea(gsym)) |
| { |
| section_size_type stype; |
| const unsigned char* view = object->section_contents(data_shndx, |
| &stype, true); |
| if (view[reloc.get_r_offset() - 2] == 0x8b) |
| break; |
| } |
| |
| if (gsym->final_value_is_known()) |
| { |
| // For a STT_GNU_IFUNC symbol we want the PLT address. |
| if (gsym->type() == elfcpp::STT_GNU_IFUNC) |
| got->add_global_plt(gsym, GOT_TYPE_STANDARD); |
| else |
| got->add_global(gsym, GOT_TYPE_STANDARD); |
| } |
| else |
| { |
| // If this symbol is not fully resolved, we need to add a |
| // GOT entry with a dynamic relocation. |
| Reloc_section* rel_dyn = target->rel_dyn_section(layout); |
| |
| // Use a GLOB_DAT rather than a RELATIVE reloc if: |
| // |
| // 1) The symbol may be defined in some other module. |
| // |
| // 2) We are building a shared library and this is a |
| // protected symbol; using GLOB_DAT means that the dynamic |
| // linker can use the address of the PLT in the main |
| // executable when appropriate so that function address |
| // comparisons work. |
| // |
| // 3) This is a STT_GNU_IFUNC symbol in position dependent |
| // code, again so that function address comparisons work. |
| if (gsym->is_from_dynobj() |
| || gsym->is_undefined() |
| || gsym->is_preemptible() |
| || (gsym->visibility() == elfcpp::STV_PROTECTED |
| && parameters->options().shared()) |
| || (gsym->type() == elfcpp::STT_GNU_IFUNC |
| && parameters->options().output_is_position_independent())) |
| got->add_global_with_rel(gsym, GOT_TYPE_STANDARD, |
| rel_dyn, elfcpp::R_386_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); |
| rel_dyn->add_global_relative(gsym, elfcpp::R_386_RELATIVE, |
| got, got_off); |
| } |
| } |
| } |
| } |
| break; |
| |
| case elfcpp::R_386_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_386_GOTOFF: |
| // A GOT-relative reference must resolve locally. |
| if (!gsym->is_defined()) |
| gold_error(_("%s: relocation R_386_GOTOFF against undefined symbol %s" |
| " cannot be used when making a shared object"), |
| object->name().c_str(), gsym->name()); |
| else if (gsym->is_from_dynobj()) |
| gold_error(_("%s: relocation R_386_GOTOFF against external symbol %s" |
| " cannot be used when making a shared object"), |
| object->name().c_str(), gsym->name()); |
| else if (gsym->is_preemptible()) |
| gold_error(_("%s: relocation R_386_GOTOFF against preemptible symbol %s" |
| " cannot be used when making a shared object"), |
| object->name().c_str(), gsym->name()); |
| // We need a GOT section. |
| target->got_section(symtab, layout); |
| break; |
| |
| case elfcpp::R_386_GOTPC: |
| // We need a GOT section. |
| target->got_section(symtab, layout); |
| break; |
| |
| // These are relocations which should only be seen by the |
| // dynamic linker, and should never be seen here. |
| case elfcpp::R_386_COPY: |
| case elfcpp::R_386_GLOB_DAT: |
| case elfcpp::R_386_JUMP_SLOT: |
| case elfcpp::R_386_RELATIVE: |
| case elfcpp::R_386_IRELATIVE: |
| case elfcpp::R_386_TLS_TPOFF: |
| case elfcpp::R_386_TLS_DTPMOD32: |
| case elfcpp::R_386_TLS_DTPOFF32: |
| case elfcpp::R_386_TLS_TPOFF32: |
| case elfcpp::R_386_TLS_DESC: |
| 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_386_TLS_GD: // Global-dynamic |
| case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url) |
| case elfcpp::R_386_TLS_DESC_CALL: |
| case elfcpp::R_386_TLS_LDM: // Local-dynamic |
| case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic |
| case elfcpp::R_386_TLS_IE: // Initial-exec |
| case elfcpp::R_386_TLS_IE_32: |
| case elfcpp::R_386_TLS_GOTIE: |
| case elfcpp::R_386_TLS_LE: // Local-exec |
| case elfcpp::R_386_TLS_LE_32: |
| { |
| const bool is_final = gsym->final_value_is_known(); |
| const tls::Tls_optimization optimized_type |
| = Target_i386::optimize_tls_reloc(is_final, r_type); |
| switch (r_type) |
| { |
| case elfcpp::R_386_TLS_GD: // Global-dynamic |
| if (optimized_type == tls::TLSOPT_NONE) |
| { |
| // Create a pair of GOT entries for the module index and |
| // dtv-relative offset. |
| Output_data_got<32, false>* got |
| = target->got_section(symtab, layout); |
| got->add_global_pair_with_rel(gsym, GOT_TYPE_TLS_PAIR, |
| target->rel_dyn_section(layout), |
| elfcpp::R_386_TLS_DTPMOD32, |
| elfcpp::R_386_TLS_DTPOFF32); |
| } |
| else if (optimized_type == tls::TLSOPT_TO_IE) |
| { |
| // Create a GOT entry for the tp-relative offset. |
| Output_data_got<32, false>* got |
| = target->got_section(symtab, layout); |
| got->add_global_with_rel(gsym, GOT_TYPE_TLS_NOFFSET, |
| target->rel_dyn_section(layout), |
| elfcpp::R_386_TLS_TPOFF); |
| } |
| else if (optimized_type != tls::TLSOPT_TO_LE) |
| unsupported_reloc_global(object, r_type, gsym); |
| break; |
| |
| case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (~oliva url) |
| target->define_tls_base_symbol(symtab, layout); |
| if (optimized_type == tls::TLSOPT_NONE) |
| { |
| // Create a double GOT entry with an R_386_TLS_DESC |
| // reloc. The R_386_TLS_DESC 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<32, false>* got = target->got_tlsdesc_section(); |
| Reloc_section* rt = target->rel_tls_desc_section(layout); |
| got->add_global_pair_with_rel(gsym, GOT_TYPE_TLS_DESC, rt, |
| elfcpp::R_386_TLS_DESC, 0); |
| } |
| else if (optimized_type == tls::TLSOPT_TO_IE) |
| { |
| // Create a GOT entry for the tp-relative offset. |
| Output_data_got<32, false>* got |
| = target->got_section(symtab, layout); |
| got->add_global_with_rel(gsym, GOT_TYPE_TLS_NOFFSET, |
| target->rel_dyn_section(layout), |
| elfcpp::R_386_TLS_TPOFF); |
| } |
| else if (optimized_type != tls::TLSOPT_TO_LE) |
| unsupported_reloc_global(object, r_type, gsym); |
| break; |
| |
| case elfcpp::R_386_TLS_DESC_CALL: |
| break; |
| |
| case elfcpp::R_386_TLS_LDM: // 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_386_TLS_LDO_32: // Alternate local-dynamic |
| break; |
| |
| case elfcpp::R_386_TLS_IE: // Initial-exec |
| case elfcpp::R_386_TLS_IE_32: |
| case elfcpp::R_386_TLS_GOTIE: |
| layout->set_has_static_tls(); |
| if (optimized_type == tls::TLSOPT_NONE) |
| { |
| // For the R_386_TLS_IE relocation, we need to create a |
| // dynamic relocation when building a shared library. |
| if (r_type == elfcpp::R_386_TLS_IE |
| && parameters->options().shared()) |
| { |
| Reloc_section* rel_dyn = target->rel_dyn_section(layout); |
| rel_dyn->add_global_relative(gsym, elfcpp::R_386_RELATIVE, |
| output_section, object, |
| data_shndx, |
| reloc.get_r_offset()); |
| } |
| // Create a GOT entry for the tp-relative offset. |
| Output_data_got<32, false>* got |
| = target->got_section(symtab, layout); |
| unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_IE_32 |
| ? elfcpp::R_386_TLS_TPOFF32 |
| : elfcpp::R_386_TLS_TPOFF); |
| unsigned int got_type = (r_type == elfcpp::R_386_TLS_IE_32 |
| ? GOT_TYPE_TLS_OFFSET |
| : GOT_TYPE_TLS_NOFFSET); |
| got->add_global_with_rel(gsym, got_type, |
| target->rel_dyn_section(layout), |
| dyn_r_type); |
| } |
| else if (optimized_type != tls::TLSOPT_TO_LE) |
| unsupported_reloc_global(object, r_type, gsym); |
| break; |
| |
| case elfcpp::R_386_TLS_LE: // Local-exec |
| case elfcpp::R_386_TLS_LE_32: |
| layout->set_has_static_tls(); |
| if (parameters->options().shared()) |
| { |
| // We need to create a dynamic relocation. |
| unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_LE_32 |
| ? elfcpp::R_386_TLS_TPOFF32 |
| : elfcpp::R_386_TLS_TPOFF); |
| Reloc_section* rel_dyn = target->rel_dyn_section(layout); |
| rel_dyn->add_global(gsym, dyn_r_type, output_section, object, |
| data_shndx, reloc.get_r_offset()); |
| } |
| break; |
| |
| default: |
| gold_unreachable(); |
| } |
| } |
| break; |
| |
| case elfcpp::R_386_32PLT: |
| case elfcpp::R_386_TLS_GD_32: |
| case elfcpp::R_386_TLS_GD_PUSH: |
| case elfcpp::R_386_TLS_GD_CALL: |
| case elfcpp::R_386_TLS_GD_POP: |
| case elfcpp::R_386_TLS_LDM_32: |
| case elfcpp::R_386_TLS_LDM_PUSH: |
| case elfcpp::R_386_TLS_LDM_CALL: |
| case elfcpp::R_386_TLS_LDM_POP: |
| case elfcpp::R_386_USED_BY_INTEL_200: |
| default: |
| unsupported_reloc_global(object, r_type, gsym); |
| break; |
| } |
| } |
| |
| // Process relocations for gc. |
| |
| void |
| Target_i386::gc_process_relocs(Symbol_table* symtab, |
| Layout* layout, |
| Sized_relobj_file<32, false>* object, |
| unsigned int data_shndx, |
| unsigned int, |
| 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) |
| { |
| gold::gc_process_relocs<32, false, Target_i386, Scan, Classify_reloc>( |
| symtab, |
| layout, |
| this, |
| object, |
| data_shndx, |
| prelocs, |
| reloc_count, |
| output_section, |
| needs_special_offset_handling, |
| local_symbol_count, |
| plocal_symbols); |
| } |
| |
| // Scan relocations for a section. |
| |
| void |
| Target_i386::scan_relocs(Symbol_table* symtab, |
| Layout* layout, |
| Sized_relobj_file<32, 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_RELA) |
| { |
| gold_error(_("%s: unsupported RELA reloc section"), |
| object->name().c_str()); |
| return; |
| } |
| |
| gold::scan_relocs<32, false, Target_i386, Scan, Classify_reloc>( |
| symtab, |
| layout, |
| this, |
| object, |
| data_shndx, |
| prelocs, |
| reloc_count, |
| output_section, |
| needs_special_offset_handling, |
| local_symbol_count, |
| plocal_symbols); |
| } |
| |
| // Finalize the sections. |
| |
| void |
| Target_i386::do_finalize_sections( |
| Layout* layout, |
| const Input_objects*, |
| Symbol_table* symtab) |
| { |
| const Reloc_section* rel_plt = (this->plt_ == NULL |
| ? NULL |
| : this->plt_->rel_plt()); |
| layout->add_target_dynamic_tags(true, this->got_plt_, rel_plt, |
| this->rel_dyn_, true, false, false); |
| |
| // 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->rel_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) |
| { |
| uint32_t data_size = this->got_plt_->current_data_size(); |
| symtab->get_sized_symbol<32>(sym)->set_symsize(data_size); |
| } |
| |
| if (parameters->doing_static_link() |
| && (this->plt_ == NULL || !this->plt_->has_irelative_section())) |
| { |
| // If linking statically, make sure that the __rel_iplt symbols |
| // were defined if necessary, even if we didn't create a PLT. |
| static const Define_symbol_in_segment syms[] = |
| { |
| { |
| "__rel_iplt_start", // name |
| elfcpp::PT_LOAD, // segment_type |
| elfcpp::PF_W, // segment_flags_set |
| elfcpp::PF(0), // segment_flags_clear |
| 0, // value |
| 0, // size |
| elfcpp::STT_NOTYPE, // type |
| elfcpp::STB_GLOBAL, // binding |
| elfcpp::STV_HIDDEN, // visibility |
| 0, // nonvis |
| Symbol::SEGMENT_START, // offset_from_base |
| true // only_if_ref |
| }, |
| { |
| "__rel_iplt_end", // name |
| elfcpp::PT_LOAD, // segment_type |
| elfcpp::PF_W, // segment_flags_set |
| elfcpp::PF(0), // segment_flags_clear |
| 0, // value |
| 0, // size |
| elfcpp::STT_NOTYPE, // type |
| elfcpp::STB_GLOBAL, // binding |
| elfcpp::STV_HIDDEN, // visibility |
| 0, // nonvis |
| Symbol::SEGMENT_START, // offset_from_base |
| true // only_if_ref |
| } |
| }; |
| |
| symtab->define_symbols(layout, 2, syms, |
| layout->script_options()->saw_sections_clause()); |
| } |
| } |
| |
| // Return whether a direct absolute static relocation needs to be applied. |
| // In cases where Scan::local() or Scan::global() has created |
| // a dynamic relocation other than R_386_RELATIVE, the addend |
| // of the relocation is carried in the data, and we must not |
| // apply the static relocation. |
| |
| inline bool |
| Target_i386::Relocate::should_apply_static_reloc(const Sized_symbol<32>* gsym, |
| unsigned int r_type, |
| bool is_32bit, |
| Output_section* output_section) |
| { |
| // If the output section is not allocated, then we didn't call |
| // scan_relocs, we didn't create a dynamic reloc, and we must apply |
| // the reloc here. |
| if ((output_section->flags() & elfcpp::SHF_ALLOC) == 0) |
| return true; |
| |
| int ref_flags = Scan::get_reference_flags(r_type); |
| |
| // For local symbols, we will have created a non-RELATIVE dynamic |
| // relocation only if (a) the output is position independent, |
| // (b) the relocation is absolute (not pc- or segment-relative), and |
| // (c) the relocation is not 32 bits wide. |
| if (gsym == NULL) |
| return !(parameters->options().output_is_position_independent() |
| && (ref_flags & Symbol::ABSOLUTE_REF) |
| && !is_32bit); |
| |
| // For global symbols, we use the same helper routines used in the |
| // scan pass. If we did not create a dynamic relocation, or if we |
| // created a RELATIVE dynamic relocation, we should apply the static |
| // relocation. |
| bool has_dyn = gsym->needs_dynamic_reloc(ref_flags); |
| bool is_rel = (ref_flags & Symbol::ABSOLUTE_REF) |
| && gsym->can_use_relative_reloc(ref_flags |
| & Symbol::FUNCTION_CALL); |
| return !has_dyn || is_rel; |
| } |
| |
| // Perform a relocation. |
| |
| inline bool |
| Target_i386::Relocate::relocate(const Relocate_info<32, false>* relinfo, |
| unsigned int, |
| Target_i386* target, |
| Output_section* output_section, |
| size_t relnum, |
| const unsigned char* preloc, |
| const Sized_symbol<32>* gsym, |
| const Symbol_value<32>* psymval, |
| unsigned char* view, |
| elfcpp::Elf_types<32>::Elf_Addr address, |
| section_size_type view_size) |
| { |
| const elfcpp::Rel<32, false> rel(preloc); |
| unsigned int r_type = elfcpp::elf_r_type<32>(rel.get_r_info()); |
| |
| if (this->skip_call_tls_get_addr_) |
| { |
| if ((r_type != elfcpp::R_386_PLT32 |
| && r_type != elfcpp::R_386_GOT32X |
| && r_type != elfcpp::R_386_PC32) |
| || gsym == NULL |
| || strcmp(gsym->name(), "___tls_get_addr") != 0) |
| { |
| gold_error_at_location(relinfo, relnum, rel.get_r_offset(), |
| _("missing expected TLS relocation")); |
| this->skip_call_tls_get_addr_ = false; |
| } |
| else |
| { |
| this->skip_call_tls_get_addr_ = false; |
| return false; |
| } |
| } |
| |
| if (view == NULL) |
| return true; |
| |
| const Sized_relobj_file<32, false>* object = relinfo->object; |
| |
| // Pick the value to use for symbols defined in shared objects. |
| Symbol_value<32> symval; |
| if (gsym != NULL |
| && gsym->type() == elfcpp::STT_GNU_IFUNC |
| && r_type == elfcpp::R_386_32 |
| && gsym->needs_dynamic_reloc(Scan::get_reference_flags(r_type)) |
| && gsym->can_use_relative_reloc(false) |
| && !gsym->is_from_dynobj() |
| && !gsym->is_undefined() |
| && !gsym->is_preemptible()) |
| { |
| // In this case we are generating a R_386_IRELATIVE reloc. We |
| // want to use the real value of the symbol, not the PLT offset. |
| } |
| else if (gsym != NULL |
| && gsym->use_plt_offset(Scan::get_reference_flags(r_type))) |
| { |
| symval.set_output_value(target->plt_address_for_global(gsym)); |
| psymval = &symval; |
| } |
| else if (gsym == NULL && psymval->is_ifunc_symbol()) |
| { |
| unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info()); |
| if (object->local_has_plt_offset(r_sym)) |
| { |
| symval.set_output_value(target->plt_address_for_local(object, r_sym)); |
| psymval = &symval; |
| } |
| } |
| |
| bool baseless; |
| |
| switch (r_type) |
| { |
| case elfcpp::R_386_NONE: |
| case elfcpp::R_386_GNU_VTINHERIT: |
| case elfcpp::R_386_GNU_VTENTRY: |
| break; |
| |
| case elfcpp::R_386_32: |
| if (should_apply_static_reloc(gsym, r_type, true, output_section)) |
| Relocate_functions<32, false>::rel32(view, object, psymval); |
| break; |
| |
| case elfcpp::R_386_PC32: |
| if (should_apply_static_reloc(gsym, r_type, true, output_section)) |
| Relocate_functions<32, false>::pcrel32(view, object, psymval, address); |
| break; |
| |
| case elfcpp::R_386_16: |
| if (should_apply_static_reloc(gsym, r_type, false, output_section)) |
| Relocate_functions<32, false>::rel16(view, object, psymval); |
| break; |
| |
| case elfcpp::R_386_PC16: |
| if (should_apply_static_reloc(gsym, r_type, false, output_section)) |
| Relocate_functions<32, false>::pcrel16(view, object, psymval, address); |
| break; |
| |
| case elfcpp::R_386_8: |
| if (should_apply_static_reloc(gsym, r_type, false, output_section)) |
| Relocate_functions<32, false>::rel8(view, object, psymval); |
| break; |
| |
| case elfcpp::R_386_PC8: |
| if (should_apply_static_reloc(gsym, r_type, false, output_section)) |
| Relocate_functions<32, false>::pcrel8(view, object, psymval, address); |
| break; |
| |
| case elfcpp::R_386_PLT32: |
| gold_assert(gsym == NULL |
| || gsym->has_plt_offset() |
| || gsym->final_value_is_known() |
| || (gsym->is_defined() |
| && !gsym->is_from_dynobj() |
| && !gsym->is_preemptible())); |
| Relocate_functions<32, false>::pcrel32(view, object, psymval, address); |
| break; |
| |
| case elfcpp::R_386_GOT32: |
| case elfcpp::R_386_GOT32X: |
| baseless = (view[-1] & 0xc7) == 0x5; |
| // R_386_GOT32 and R_386_GOT32X don't work without base register |
| // when generating a position-independent output file. |
| if (baseless |
| && parameters->options().output_is_position_independent()) |
| { |
| if(gsym) |
| gold_error_at_location(relinfo, relnum, rel.get_r_offset(), |
| _("unexpected reloc %u against global symbol %s without base register in object file when generating a position-independent output file"), |
| r_type, gsym->demangled_name().c_str()); |
| else |
| gold_error_at_location(relinfo, relnum, rel.get_r_offset(), |
| _("unexpected reloc %u against local symbol without base register in object file when generating a position-independent output file"), |
| r_type); |
| } |
| |
| // Convert |
| // mov foo@GOT(%reg), %reg |
| // to |
| // lea foo@GOTOFF(%reg), %reg |
| // if possible. |
| if (rel.get_r_offset() >= 2 |
| && view[-2] == 0x8b |
| && ((gsym == NULL && !psymval->is_ifunc_symbol()) |
| || (gsym != NULL |
| && Target_i386::can_convert_mov_to_lea(gsym)))) |
| { |
| view[-2] = 0x8d; |
| elfcpp::Elf_types<32>::Elf_Addr value; |
| value = psymval->value(object, 0); |
| // Don't subtract the .got.plt section address for baseless |
| // addressing. |
| if (!baseless) |
| value -= target->got_plt_section()->address(); |
| Relocate_functions<32, false>::rel32(view, value); |
| } |
| else |
| { |
| // 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. |
| unsigned int got_offset = 0; |
| 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<32>(rel.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()); |
| } |
| // Add the .got.plt section address for baseless addressing. |
| if (baseless) |
| got_offset += target->got_plt_section()->address(); |
| Relocate_functions<32, false>::rel32(view, got_offset); |
| } |
| break; |
| |
| case elfcpp::R_386_GOTOFF: |
| { |
| elfcpp::Elf_types<32>::Elf_Addr reladdr; |
| reladdr = target->got_plt_section()->address(); |
| Relocate_functions<32, false>::pcrel32(view, object, psymval, reladdr); |
| } |
| break; |
| |
| case elfcpp::R_386_GOTPC: |
| { |
| elfcpp::Elf_types<32>::Elf_Addr value; |
| value = target->got_plt_section()->address(); |
| Relocate_functions<32, false>::pcrel32(view, value, address); |
| } |
| break; |
| |
| case elfcpp::R_386_COPY: |
| case elfcpp::R_386_GLOB_DAT: |
| case elfcpp::R_386_JUMP_SLOT: |
| case elfcpp::R_386_RELATIVE: |
| case elfcpp::R_386_IRELATIVE: |
| // These are outstanding tls relocs, which are unexpected when |
| // linking. |
| case elfcpp::R_386_TLS_TPOFF: |
| case elfcpp::R_386_TLS_DTPMOD32: |
| case elfcpp::R_386_TLS_DTPOFF32: |
| case elfcpp::R_386_TLS_TPOFF32: |
| case elfcpp::R_386_TLS_DESC: |
| gold_error_at_location(relinfo, relnum, rel.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_386_TLS_GD: // Global-dynamic |
| case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url) |
| case elfcpp::R_386_TLS_DESC_CALL: |
| case elfcpp::R_386_TLS_LDM: // Local-dynamic |
| case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic |
| case elfcpp::R_386_TLS_IE: // Initial-exec |
| case elfcpp::R_386_TLS_IE_32: |
| case elfcpp::R_386_TLS_GOTIE: |
| case elfcpp::R_386_TLS_LE: // Local-exec |
| case elfcpp::R_386_TLS_LE_32: |
| this->relocate_tls(relinfo, target, relnum, rel, r_type, gsym, psymval, |
| view, address, view_size); |
| break; |
|