// target-reloc.h -- target specific relocation support -*- C++ -*- // Copyright (C) 2006-2017 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. #ifndef GOLD_TARGET_RELOC_H #define GOLD_TARGET_RELOC_H #include "elfcpp.h" #include "symtab.h" #include "object.h" #include "reloc.h" #include "reloc-types.h" namespace gold { // This function implements the generic part of reloc scanning. The // template parameter Scan must be a class type which provides two // functions: local() and global(). Those functions implement the // machine specific part of scanning. We do it this way to // avoid making a function call for each relocation, and to avoid // repeating the generic code for each target. template<int size, bool big_endian, typename Target_type, typename Scan, typename Classify_reloc> inline void scan_relocs( Symbol_table* symtab, Layout* layout, Target_type* target, Sized_relobj_file<size, big_endian>* object, unsigned int data_shndx, const unsigned char* prelocs, size_t reloc_count, Output_section* output_section, bool needs_special_offset_handling, size_t local_count, const unsigned char* plocal_syms) { typedef typename Classify_reloc::Reltype Reltype; const int reloc_size = Classify_reloc::reloc_size; const int sym_size = elfcpp::Elf_sizes<size>::sym_size; Scan scan; for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size) { Reltype reloc(prelocs); if (needs_special_offset_handling && !output_section->is_input_address_mapped(object, data_shndx, reloc.get_r_offset())) continue; unsigned int r_sym = Classify_reloc::get_r_sym(&reloc); unsigned int r_type = Classify_reloc::get_r_type(&reloc); if (r_sym < local_count) { gold_assert(plocal_syms != NULL); typename elfcpp::Sym<size, big_endian> lsym(plocal_syms + r_sym * sym_size); unsigned int shndx = lsym.get_st_shndx(); bool is_ordinary; shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary); // If RELOC is a relocation against a local symbol in a // section we are discarding then we can ignore it. It will // eventually become a reloc against the value zero. // // FIXME: We should issue a warning if this is an // allocated section; is this the best place to do it? // // FIXME: The old GNU linker would in some cases look // for the linkonce section which caused this section to // be discarded, and, if the other section was the same // size, change the reloc to refer to the other section. // That seems risky and weird to me, and I don't know of // any case where it is actually required. bool is_discarded = (is_ordinary && shndx != elfcpp::SHN_UNDEF && !object->is_section_included(shndx) && !symtab->is_section_folded(object, shndx)); scan.local(symtab, layout, target, object, data_shndx, output_section, reloc, r_type, lsym, is_discarded); } else { Symbol* gsym = object->global_symbol(r_sym); gold_assert(gsym != NULL); if (gsym->is_forwarder()) gsym = symtab->resolve_forwards(gsym); scan.global(symtab, layout, target, object, data_shndx, output_section, reloc, r_type, gsym); } } } // Behavior for relocations to discarded comdat sections. enum Comdat_behavior { CB_UNDETERMINED, // Not yet determined -- need to look at section name. CB_PRETEND, // Attempt to map to the corresponding kept section. CB_IGNORE, // Ignore the relocation. CB_WARNING // Print a warning. }; class Default_comdat_behavior { public: // Decide what the linker should do for relocations that refer to // discarded comdat sections. This decision is based on the name of // the section being relocated. inline Comdat_behavior get(const char* name) { if (Layout::is_debug_info_section(name)) return CB_PRETEND; if (strcmp(name, ".eh_frame") == 0 || strcmp(name, ".gcc_except_table") == 0) return CB_IGNORE; return CB_WARNING; } }; // Give an error for a symbol with non-default visibility which is not // defined locally. inline void visibility_error(const Symbol* sym) { const char* v; switch (sym->visibility()) { case elfcpp::STV_INTERNAL: v = _("internal"); break; case elfcpp::STV_HIDDEN: v = _("hidden"); break; case elfcpp::STV_PROTECTED: v = _("protected"); break; default: gold_unreachable(); } gold_error(_("%s symbol '%s' is not defined locally"), v, sym->name()); } // Return true if we are should issue an error saying that SYM is an // undefined symbol. This is called if there is a relocation against // SYM. inline bool issue_undefined_symbol_error(const Symbol* sym) { // We only report global symbols. if (sym == NULL) return false; // We only report undefined symbols. if (!sym->is_undefined() && !sym->is_placeholder()) return false; // We don't report weak symbols. if (sym->is_weak_undefined()) return false; // We don't report symbols defined in discarded sections, // unless they're placeholder symbols that should have been // provided by a plugin. if (sym->is_defined_in_discarded_section() && !sym->is_placeholder()) return false; // If the target defines this symbol, don't report it here. if (parameters->target().is_defined_by_abi(sym)) return false; // See if we've been told to ignore whether this symbol is // undefined. const char* const u = parameters->options().unresolved_symbols(); if (u != NULL) { if (strcmp(u, "ignore-all") == 0) return false; if (strcmp(u, "report-all") == 0) return true; if (strcmp(u, "ignore-in-object-files") == 0 && !sym->in_dyn()) return false; if (strcmp(u, "ignore-in-shared-libs") == 0 && !sym->in_reg()) return false; } // If the symbol is hidden, report it. if (sym->visibility() == elfcpp::STV_HIDDEN) return true; // When creating a shared library, only report unresolved symbols if // -z defs was used. if (parameters->options().shared() && !parameters->options().defs()) return false; // Otherwise issue a warning. return true; } // This function implements the generic part of relocation processing. // The template parameter Relocate must be a class type which provides // a single function, relocate(), which implements the machine // specific part of a relocation. // The template parameter Relocate_comdat_behavior is a class type // which provides a single function, get(), which determines what the // linker should do for relocations that refer to discarded comdat // sections. // SIZE is the ELF size: 32 or 64. BIG_ENDIAN is the endianness of // the data. SH_TYPE is the section type: SHT_REL or SHT_RELA. // RELOCATE implements operator() to do a relocation. // PRELOCS points to the relocation data. RELOC_COUNT is the number // of relocs. OUTPUT_SECTION is the output section. // NEEDS_SPECIAL_OFFSET_HANDLING is true if input offsets need to be // mapped to output offsets. // VIEW is the section data, VIEW_ADDRESS is its memory address, and // VIEW_SIZE is the size. These refer to the input section, unless // NEEDS_SPECIAL_OFFSET_HANDLING is true, in which case they refer to // the output section. // RELOC_SYMBOL_CHANGES is used for -fsplit-stack support. If it is // not NULL, it is a vector indexed by relocation index. If that // entry is not NULL, it points to a global symbol which used as the // symbol for the relocation, ignoring the symbol index in the // relocation. template<int size, bool big_endian, typename Target_type, typename Relocate, typename Relocate_comdat_behavior, typename Classify_reloc> inline void relocate_section( const Relocate_info<size, big_endian>* relinfo, Target_type* target, const unsigned char* prelocs, size_t reloc_count, Output_section* output_section, bool needs_special_offset_handling, unsigned char* view, typename elfcpp::Elf_types<size>::Elf_Addr view_address, section_size_type view_size, const Reloc_symbol_changes* reloc_symbol_changes) { typedef typename Classify_reloc::Reltype Reltype; const int reloc_size = Classify_reloc::reloc_size; Relocate relocate; Relocate_comdat_behavior relocate_comdat_behavior; Sized_relobj_file<size, big_endian>* object = relinfo->object; unsigned int local_count = object->local_symbol_count(); Comdat_behavior comdat_behavior = CB_UNDETERMINED; for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size) { Reltype reloc(prelocs); section_offset_type offset = convert_to_section_size_type(reloc.get_r_offset()); if (needs_special_offset_handling) { offset = output_section->output_offset(relinfo->object, relinfo->data_shndx, offset); if (offset == -1) continue; } unsigned int r_sym = Classify_reloc::get_r_sym(&reloc); const Sized_symbol<size>* sym; Symbol_value<size> symval; const Symbol_value<size> *psymval; bool is_defined_in_discarded_section; unsigned int shndx; if (r_sym < local_count && (reloc_symbol_changes == NULL || (*reloc_symbol_changes)[i] == NULL)) { sym = NULL; psymval = object->local_symbol(r_sym); // If the local symbol belongs to a section we are discarding, // and that section is a debug section, try to find the // corresponding kept section and map this symbol to its // counterpart in the kept section. The symbol must not // correspond to a section we are folding. bool is_ordinary; shndx = psymval->input_shndx(&is_ordinary); is_defined_in_discarded_section = (is_ordinary && shndx != elfcpp::SHN_UNDEF && !object->is_section_included(shndx) && !relinfo->symtab->is_section_folded(object, shndx)); } else { const Symbol* gsym; if (reloc_symbol_changes != NULL && (*reloc_symbol_changes)[i] != NULL) gsym = (*reloc_symbol_changes)[i]; else { gsym = object->global_symbol(r_sym); gold_assert(gsym != NULL); if (gsym->is_forwarder()) gsym = relinfo->symtab->resolve_forwards(gsym); } sym = static_cast<const Sized_symbol<size>*>(gsym); if (sym->has_symtab_index() && sym->symtab_index() != -1U) symval.set_output_symtab_index(sym->symtab_index()); else symval.set_no_output_symtab_entry(); symval.set_output_value(sym->value()); if (gsym->type() == elfcpp::STT_TLS) symval.set_is_tls_symbol(); else if (gsym->type() == elfcpp::STT_GNU_IFUNC) symval.set_is_ifunc_symbol(); psymval = &symval; is_defined_in_discarded_section = (gsym->is_defined_in_discarded_section() && gsym->is_undefined()); shndx = 0; } Symbol_value<size> symval2; if (is_defined_in_discarded_section) { if (comdat_behavior == CB_UNDETERMINED) { std::string name = object->section_name(relinfo->data_shndx); comdat_behavior = relocate_comdat_behavior.get(name.c_str()); } if (comdat_behavior == CB_PRETEND) { // FIXME: This case does not work for global symbols. // We have no place to store the original section index. // Fortunately this does not matter for comdat sections, // only for sections explicitly discarded by a linker // script. bool found; typename elfcpp::Elf_types<size>::Elf_Addr value = object->map_to_kept_section(shndx, &found); if (found) symval2.set_output_value(value + psymval->input_value()); else symval2.set_output_value(0); } else { if (comdat_behavior == CB_WARNING) gold_warning_at_location(relinfo, i, offset, _("relocation refers to discarded " "section")); symval2.set_output_value(0); } symval2.set_no_output_symtab_entry(); psymval = &symval2; } // If OFFSET is out of range, still let the target decide to // ignore the relocation. Pass in NULL as the VIEW argument so // that it can return quickly without trashing an invalid memory // address. unsigned char *v = view + offset; if (offset < 0 || static_cast<section_size_type>(offset) >= view_size) v = NULL; if (!relocate.relocate(relinfo, Classify_reloc::sh_type, target, output_section, i, prelocs, sym, psymval, v, view_address + offset, view_size)) continue; if (v == NULL) { gold_error_at_location(relinfo, i, offset, _("reloc has bad offset %zu"), static_cast<size_t>(offset)); continue; } if (issue_undefined_symbol_error(sym)) gold_undefined_symbol_at_location(sym, relinfo, i, offset); else if (sym != NULL && sym->visibility() != elfcpp::STV_DEFAULT && (sym->is_strong_undefined() || sym->is_from_dynobj())) visibility_error(sym); if (sym != NULL && sym->has_warning()) relinfo->symtab->issue_warning(sym, relinfo, i, offset); } } // Apply an incremental relocation. template<int size, bool big_endian, typename Target_type, typename Relocate> void apply_relocation(const Relocate_info<size, big_endian>* relinfo, Target_type* target, typename elfcpp::Elf_types<size>::Elf_Addr r_offset, unsigned int r_type, typename elfcpp::Elf_types<size>::Elf_Swxword r_addend, const Symbol* gsym, unsigned char* view, typename elfcpp::Elf_types<size>::Elf_Addr address, section_size_type view_size) { // Construct the ELF relocation in a temporary buffer. const int reloc_size = elfcpp::Elf_sizes<size>::rela_size; unsigned char relbuf[reloc_size]; elfcpp::Rela_write<size, big_endian> orel(relbuf); orel.put_r_offset(r_offset); orel.put_r_info(elfcpp::elf_r_info<size>(0, r_type)); orel.put_r_addend(r_addend); // Setup a Symbol_value for the global symbol. const Sized_symbol<size>* sym = static_cast<const Sized_symbol<size>*>(gsym); Symbol_value<size> symval; gold_assert(sym->has_symtab_index() && sym->symtab_index() != -1U); symval.set_output_symtab_index(sym->symtab_index()); symval.set_output_value(sym->value()); if (gsym->type() == elfcpp::STT_TLS) symval.set_is_tls_symbol(); else if (gsym->type() == elfcpp::STT_GNU_IFUNC) symval.set_is_ifunc_symbol(); Relocate relocate; relocate.relocate(relinfo, elfcpp::SHT_RELA, target, NULL, -1U, relbuf, sym, &symval, view + r_offset, address + r_offset, view_size); } // A class for inquiring about properties of a relocation, // used while scanning relocs during a relocatable link and // garbage collection. This class may be used as the default // for SHT_RELA targets, but SHT_REL targets must implement // a derived class that overrides get_size_for_reloc. // The MIPS-64 target also needs to override the methods // for accessing the r_sym and r_type fields of a relocation, // due to its non-standard use of the r_info field. template<int sh_type_, int size, bool big_endian> class Default_classify_reloc { public: typedef typename Reloc_types<sh_type_, size, big_endian>::Reloc Reltype; typedef typename Reloc_types<sh_type_, size, big_endian>::Reloc_write Reltype_write; static const int reloc_size = Reloc_types<sh_type_, size, big_endian>::reloc_size; static const int sh_type = sh_type_; // Return the symbol referred to by the relocation. static inline unsigned int get_r_sym(const Reltype* reloc) { return elfcpp::elf_r_sym<size>(reloc->get_r_info()); } // Return the type of the relocation. static inline unsigned int get_r_type(const Reltype* reloc) { return elfcpp::elf_r_type<size>(reloc->get_r_info()); } // Return the explicit addend of the relocation (return 0 for SHT_REL). static inline typename elfcpp::Elf_types<size>::Elf_Swxword get_r_addend(const Reltype* reloc) { return Reloc_types<sh_type_, size, big_endian>::get_reloc_addend(reloc); } // Write the r_info field to a new reloc, using the r_info field from // the original reloc, replacing the r_sym field with R_SYM. static inline void put_r_info(Reltype_write* new_reloc, Reltype* reloc, unsigned int r_sym) { unsigned int r_type = elfcpp::elf_r_type<size>(reloc->get_r_info()); new_reloc->put_r_info(elfcpp::elf_r_info<size>(r_sym, r_type)); } // Write the r_addend field to a new reloc. static inline void put_r_addend(Reltype_write* to, typename elfcpp::Elf_types<size>::Elf_Swxword addend) { Reloc_types<sh_type_, size, big_endian>::set_reloc_addend(to, addend); } // Return the size of the addend of the relocation (only used for SHT_REL). static unsigned int get_size_for_reloc(unsigned int, Relobj*) { gold_unreachable(); return 0; } }; // This class may be used as a typical class for the // Scan_relocatable_reloc parameter to scan_relocatable_relocs. // This class is intended to capture the most typical target behaviour, // while still permitting targets to define their own independent class // for Scan_relocatable_reloc. template<typename Classify_reloc> class Default_scan_relocatable_relocs { public: typedef typename Classify_reloc::Reltype Reltype; static const int reloc_size = Classify_reloc::reloc_size; static const int sh_type = Classify_reloc::sh_type; // Return the symbol referred to by the relocation. static inline unsigned int get_r_sym(const Reltype* reloc) { return Classify_reloc::get_r_sym(reloc); } // Return the type of the relocation. static inline unsigned int get_r_type(const Reltype* reloc) { return Classify_reloc::get_r_type(reloc); } // Return the strategy to use for a local symbol which is not a // section symbol, given the relocation type. inline Relocatable_relocs::Reloc_strategy local_non_section_strategy(unsigned int r_type, Relobj*, unsigned int r_sym) { // We assume that relocation type 0 is NONE. Targets which are // different must override. if (r_type == 0 && r_sym == 0) return Relocatable_relocs::RELOC_DISCARD; return Relocatable_relocs::RELOC_COPY; } // Return the strategy to use for a local symbol which is a section // symbol, given the relocation type. inline Relocatable_relocs::Reloc_strategy local_section_strategy(unsigned int r_type, Relobj* object) { if (sh_type == elfcpp::SHT_RELA) return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA; else { switch (Classify_reloc::get_size_for_reloc(r_type, object)) { case 0: return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_0; case 1: return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_1; case 2: return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_2; case 4: return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4; case 8: return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_8; default: gold_unreachable(); } } } // Return the strategy to use for a global symbol, given the // relocation type, the object, and the symbol index. inline Relocatable_relocs::Reloc_strategy global_strategy(unsigned int, Relobj*, unsigned int) { return Relocatable_relocs::RELOC_COPY; } }; // This is a strategy class used with scan_relocatable_relocs // and --emit-relocs. template<typename Classify_reloc> class Default_emit_relocs_strategy { public: typedef typename Classify_reloc::Reltype Reltype; static const int reloc_size = Classify_reloc::reloc_size; static const int sh_type = Classify_reloc::sh_type; // Return the symbol referred to by the relocation. static inline unsigned int get_r_sym(const Reltype* reloc) { return Classify_reloc::get_r_sym(reloc); } // Return the type of the relocation. static inline unsigned int get_r_type(const Reltype* reloc) { return Classify_reloc::get_r_type(reloc); } // A local non-section symbol. inline Relocatable_relocs::Reloc_strategy local_non_section_strategy(unsigned int, Relobj*, unsigned int) { return Relocatable_relocs::RELOC_COPY; } // A local section symbol. inline Relocatable_relocs::Reloc_strategy local_section_strategy(unsigned int, Relobj*) { if (sh_type == elfcpp::SHT_RELA) return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA; else { // The addend is stored in the section contents. Since this // is not a relocatable link, we are going to apply the // relocation contents to the section as usual. This means // that we have no way to record the original addend. If the // original addend is not zero, there is basically no way for // the user to handle this correctly. Caveat emptor. return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_0; } } // A global symbol. inline Relocatable_relocs::Reloc_strategy global_strategy(unsigned int, Relobj*, unsigned int) { return Relocatable_relocs::RELOC_COPY; } }; // Scan relocs during a relocatable link. This is a default // definition which should work for most targets. // Scan_relocatable_reloc must name a class type which provides three // functions which return a Relocatable_relocs::Reloc_strategy code: // global_strategy, local_non_section_strategy, and // local_section_strategy. Most targets should be able to use // Default_scan_relocatable_relocs as this class. template<int size, bool big_endian, typename Scan_relocatable_reloc> void scan_relocatable_relocs( Symbol_table*, Layout*, Sized_relobj_file<size, big_endian>* object, unsigned int data_shndx, const unsigned char* prelocs, size_t reloc_count, Output_section* output_section, bool needs_special_offset_handling, size_t local_symbol_count, const unsigned char* plocal_syms, Relocatable_relocs* rr) { typedef typename Scan_relocatable_reloc::Reltype Reltype; const int reloc_size = Scan_relocatable_reloc::reloc_size; const int sym_size = elfcpp::Elf_sizes<size>::sym_size; Scan_relocatable_reloc scan; for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size) { Reltype reloc(prelocs); Relocatable_relocs::Reloc_strategy strategy; if (needs_special_offset_handling && !output_section->is_input_address_mapped(object, data_shndx, reloc.get_r_offset())) strategy = Relocatable_relocs::RELOC_DISCARD; else { const unsigned int r_sym = Scan_relocatable_reloc::get_r_sym(&reloc); const unsigned int r_type = Scan_relocatable_reloc::get_r_type(&reloc); if (r_sym >= local_symbol_count) strategy = scan.global_strategy(r_type, object, r_sym); else { gold_assert(plocal_syms != NULL); typename elfcpp::Sym<size, big_endian> lsym(plocal_syms + r_sym * sym_size); unsigned int shndx = lsym.get_st_shndx(); bool is_ordinary; shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary); if (is_ordinary && shndx != elfcpp::SHN_UNDEF && !object->is_section_included(shndx)) { // RELOC is a relocation against a local symbol // defined in a section we are discarding. Discard // the reloc. FIXME: Should we issue a warning? strategy = Relocatable_relocs::RELOC_DISCARD; } else if (lsym.get_st_type() != elfcpp::STT_SECTION) strategy = scan.local_non_section_strategy(r_type, object, r_sym); else { strategy = scan.local_section_strategy(r_type, object); if (strategy != Relocatable_relocs::RELOC_DISCARD) object->output_section(shndx)->set_needs_symtab_index(); } if (strategy == Relocatable_relocs::RELOC_COPY) object->set_must_have_output_symtab_entry(r_sym); } } rr->set_next_reloc_strategy(strategy); } } // Relocate relocs. Called for a relocatable link, and for --emit-relocs. // This is a default definition which should work for most targets. template<int size, bool big_endian, typename Classify_reloc> void relocate_relocs( const Relocate_info<size, big_endian>* relinfo, const unsigned char* prelocs, size_t reloc_count, Output_section* output_section, typename elfcpp::Elf_types<size>::Elf_Off offset_in_output_section, unsigned char* view, typename elfcpp::Elf_types<size>::Elf_Addr view_address, section_size_type view_size, unsigned char* reloc_view, section_size_type reloc_view_size) { typedef typename elfcpp::Elf_types<size>::Elf_Addr Address; typedef typename Classify_reloc::Reltype Reltype; typedef typename Classify_reloc::Reltype_write Reltype_write; const int reloc_size = Classify_reloc::reloc_size; const Address invalid_address = static_cast<Address>(0) - 1; Sized_relobj_file<size, big_endian>* const object = relinfo->object; const unsigned int local_count = object->local_symbol_count(); unsigned char* pwrite = reloc_view; for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size) { Relocatable_relocs::Reloc_strategy strategy = relinfo->rr->strategy(i); if (strategy == Relocatable_relocs::RELOC_DISCARD) continue; if (strategy == Relocatable_relocs::RELOC_SPECIAL) { // Target wants to handle this relocation. Sized_target<size, big_endian>* target = parameters->sized_target<size, big_endian>(); target->relocate_special_relocatable(relinfo, Classify_reloc::sh_type, prelocs, i, output_section, offset_in_output_section, view, view_address, view_size, pwrite); pwrite += reloc_size; continue; } Reltype reloc(prelocs); Reltype_write reloc_write(pwrite); const unsigned int r_sym = Classify_reloc::get_r_sym(&reloc); // Get the new symbol index. Output_section* os = NULL; unsigned int new_symndx; if (r_sym < local_count) { switch (strategy) { case Relocatable_relocs::RELOC_COPY: if (r_sym == 0) new_symndx = 0; else { new_symndx = object->symtab_index(r_sym); gold_assert(new_symndx != -1U); } break; case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA: case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_0: case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_1: case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_2: case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4: case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_8: case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4_UNALIGNED: { // We are adjusting a section symbol. We need to find // the symbol table index of the section symbol for // the output section corresponding to input section // in which this symbol is defined. gold_assert(r_sym < local_count); bool is_ordinary; unsigned int shndx = object->local_symbol_input_shndx(r_sym, &is_ordinary); gold_assert(is_ordinary); os = object->output_section(shndx); gold_assert(os != NULL); gold_assert(os->needs_symtab_index()); new_symndx = os->symtab_index(); } break; default: gold_unreachable(); } } else { const Symbol* gsym = object->global_symbol(r_sym); gold_assert(gsym != NULL); if (gsym->is_forwarder()) gsym = relinfo->symtab->resolve_forwards(gsym); gold_assert(gsym->has_symtab_index()); new_symndx = gsym->symtab_index(); } // Get the new offset--the location in the output section where // this relocation should be applied. Address offset = reloc.get_r_offset(); Address new_offset; if (offset_in_output_section != invalid_address) new_offset = offset + offset_in_output_section; else { section_offset_type sot_offset = convert_types<section_offset_type, Address>(offset); section_offset_type new_sot_offset = output_section->output_offset(object, relinfo->data_shndx, sot_offset); gold_assert(new_sot_offset != -1); new_offset = new_sot_offset; } // In an object file, r_offset is an offset within the section. // In an executable or dynamic object, generated by // --emit-relocs, r_offset is an absolute address. if (!parameters->options().relocatable()) { new_offset += view_address; if (offset_in_output_section != invalid_address) new_offset -= offset_in_output_section; } reloc_write.put_r_offset(new_offset); Classify_reloc::put_r_info(&reloc_write, &reloc, new_symndx); // Handle the reloc addend based on the strategy. if (strategy == Relocatable_relocs::RELOC_COPY) { if (Classify_reloc::sh_type == elfcpp::SHT_RELA) Classify_reloc::put_r_addend(&reloc_write, Classify_reloc::get_r_addend(&reloc)); } else { // The relocation uses a section symbol in the input file. // We are adjusting it to use a section symbol in the output // file. The input section symbol refers to some address in // the input section. We need the relocation in the output // file to refer to that same address. This adjustment to // the addend is the same calculation we use for a simple // absolute relocation for the input section symbol. const Symbol_value<size>* psymval = object->local_symbol(r_sym); unsigned char* padd = view + offset; switch (strategy) { case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA: { typename elfcpp::Elf_types<size>::Elf_Swxword addend; addend = Classify_reloc::get_r_addend(&reloc); gold_assert(os != NULL); addend = psymval->value(object, addend) - os->address(); Classify_reloc::put_r_addend(&reloc_write, addend); } break; case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_0: break; case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_1: Relocate_functions<size, big_endian>::rel8(padd, object, psymval); break; case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_2: Relocate_functions<size, big_endian>::rel16(padd, object, psymval); break; case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4: Relocate_functions<size, big_endian>::rel32(padd, object, psymval); break; case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_8: Relocate_functions<size, big_endian>::rel64(padd, object, psymval); break; case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4_UNALIGNED: Relocate_functions<size, big_endian>::rel32_unaligned(padd, object, psymval); break; default: gold_unreachable(); } } pwrite += reloc_size; } gold_assert(static_cast<section_size_type>(pwrite - reloc_view) == reloc_view_size); } } // End namespace gold. #endif // !defined(GOLD_TARGET_RELOC_H)