X-Git-Url: http://git.efficios.com/?a=blobdiff_plain;f=gold%2Ftarget-reloc.h;h=97e45da6198e2d6f1648144d19f13d73955a1258;hb=db178f47dd4c9d2882da42a8915018d1fb90ea17;hp=5b057ac0fb808364ef94c31c86245540427b05b1;hpb=c06b7b0ba3f6aaa4a3f9586689ef8bfdbd17454e;p=deliverable%2Fbinutils-gdb.git diff --git a/gold/target-reloc.h b/gold/target-reloc.h index 5b057ac0fb..97e45da619 100644 --- a/gold/target-reloc.h +++ b/gold/target-reloc.h @@ -1,39 +1,62 @@ // target-reloc.h -- target specific relocation support -*- C++ -*- +// Copyright (C) 2006-2019 Free Software Foundation, Inc. +// Written by Ian Lance Taylor . + +// 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 "object.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. This -// is an inline function which takes a class whose operator() -// implements the machine specific part of scanning. We do it this -// way to avoidmaking a function call for each relocation, and to -// avoid repeating the generic code for each target. +// 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 +template inline void scan_relocs( - const General_options& options, Symbol_table* symtab, Layout* layout, Target_type* target, - Sized_relobj* object, + Sized_relobj_file* 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, - Symbol** global_syms) + const unsigned char* plocal_syms) { - typedef typename Reloc_types::Reloc Reltype; - const int reloc_size = Reloc_types::reloc_size; + typedef typename Classify_reloc::Reltype Reltype; + const int reloc_size = Classify_reloc::reloc_size; const int sym_size = elfcpp::Elf_sizes::sym_size; Scan scan; @@ -41,146 +64,936 @@ scan_relocs( { Reltype reloc(prelocs); - typename elfcpp::Elf_types::Elf_WXword r_info = reloc.get_r_info(); - unsigned int r_sym = elfcpp::elf_r_sym(r_info); - unsigned int r_type = elfcpp::elf_r_type(r_info); + 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) { - assert(plocal_syms != NULL); + gold_assert(plocal_syms != NULL); typename elfcpp::Sym lsym(plocal_syms + r_sym * sym_size); - const unsigned int shndx = lsym.get_st_shndx(); - if (shndx < elfcpp::SHN_LORESERVE - && shndx != elfcpp::SHN_UNDEF - && !object->is_section_included(lsym.get_st_shndx())) - { - // RELOC is a relocation against a local symbol in a - // section we are discarding. We can ignore this - // relocation. 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. - - continue; - } - - scan.local(options, symtab, layout, target, object, reloc, r_type, - lsym); + 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 = global_syms[r_sym - local_count]; - assert(gsym != NULL); + Symbol* gsym = object->global_symbol(r_sym); + gold_assert(gsym != NULL); if (gsym->is_forwarder()) gsym = symtab->resolve_forwards(gsym); - scan.global(options, symtab, layout, target, object, reloc, r_type, - 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_ERROR // Print an error. +}; + +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_ERROR; + } +}; + +// 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; +} + +template +inline void +issue_discarded_error( + const Relocate_info* relinfo, + size_t shndx, + section_offset_type offset, + unsigned int r_sym, + const Symbol* gsym) +{ + Sized_relobj_file* object = relinfo->object; + + if (gsym == NULL) + { + gold_error_at_location( + relinfo, shndx, offset, + _("relocation refers to local symbol \"%s\" [%u], " + "which is defined in a discarded section"), + object->get_symbol_name(r_sym), r_sym); + } + else + { + gold_error_at_location( + relinfo, shndx, offset, + _("relocation refers to global symbol \"%s\", " + "which is defined in a discarded section"), + gsym->demangled_name().c_str()); + } + + bool is_ordinary; + typename elfcpp::Elf_types::Elf_Addr value; + unsigned int orig_shndx = object->symbol_section_and_value(r_sym, &value, + &is_ordinary); + if (orig_shndx != elfcpp::SHN_UNDEF) + { + unsigned int key_symndx; + Relobj* kept_obj = object->find_kept_section_object(orig_shndx, + &key_symndx); + if (key_symndx != 0) + gold_info(_(" section group signature: \"%s\""), + object->get_symbol_name(key_symndx)); + if (kept_obj != NULL) + gold_info(_(" prevailing definition is from %s"), + kept_obj->name().c_str()); + } +} + // This function implements the generic part of relocation processing. -// This is an inline function which take a class whose operator() -// implements the machine specific part of relocation. We do it this -// way to avoid making a function call for each relocation, and to -// avoid repeating the generic relocation handling code for each -// target. +// 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. VIEW is the section data, VIEW_ADDRESS is its memory -// address, and VIEW_SIZE is the size. +// of relocs. OUTPUT_SECTION is the output section. +// NEEDS_SPECIAL_OFFSET_HANDLING is true if input offsets need to be +// mapped to output offsets. -template +// 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 inline void relocate_section( const Relocate_info* 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::Elf_Addr view_address, - off_t view_size) + section_size_type view_size, + const Reloc_symbol_changes* reloc_symbol_changes) { - typedef typename Reloc_types::Reloc Reltype; - const int reloc_size = Reloc_types::reloc_size; + 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* object = relinfo->object; + unsigned int local_count = object->local_symbol_count(); - unsigned int local_count = relinfo->local_symbol_count; - const typename Sized_relobj::Local_values* local_values = - relinfo->local_values; - const Symbol* const * global_syms = relinfo->symbols; + Comdat_behavior comdat_behavior = CB_UNDETERMINED; for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size) { Reltype reloc(prelocs); - off_t offset = reloc.get_r_offset(); + section_offset_type offset = + convert_to_section_size_type(reloc.get_r_offset()); - typename elfcpp::Elf_types::Elf_WXword r_info = reloc.get_r_info(); - unsigned int r_sym = elfcpp::elf_r_sym(r_info); - unsigned int r_type = elfcpp::elf_r_type(r_info); + 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* sym; - typename elfcpp::Elf_types::Elf_Addr value; - if (r_sym < local_count) + Symbol_value symval; + const Symbol_value *psymval; + bool is_defined_in_discarded_section; + unsigned int shndx; + const Symbol* gsym = NULL; + if (r_sym < local_count + && (reloc_symbol_changes == NULL + || (*reloc_symbol_changes)[i] == NULL)) { sym = NULL; - value = (*local_values)[r_sym]; + 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 = global_syms[r_sym - local_count]; - assert(gsym != NULL); - if (gsym->is_forwarder()) - gsym = relinfo->symtab->resolve_forwards(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*>(gsym); - value = sym->value(); + 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 symval2; + if (is_defined_in_discarded_section) + { + std::string name = object->section_name(relinfo->data_shndx); + + if (comdat_behavior == CB_UNDETERMINED) + 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::Elf_Addr value = + object->map_to_kept_section(shndx, name, &found); + if (found) + symval2.set_output_value(value + psymval->input_value()); + else + symval2.set_output_value(0); + } + else + { + if (comdat_behavior == CB_ERROR) + issue_discarded_error(relinfo, i, offset, r_sym, gsym); + symval2.set_output_value(0); + } + symval2.set_no_output_symtab_entry(); + psymval = &symval2; } - if (!relocate.relocate(relinfo, target, i, reloc, r_type, sym, value, - view + offset, view_address + offset, view_size)) + // 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(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 (offset < 0 || offset >= view_size) + if (v == NULL) { - fprintf(stderr, _("%s: %s: reloc has bad offset %zu\n"), - program_name, relinfo->location(i, offset).c_str(), - static_cast(offset)); - gold_exit(false); + gold_error_at_location(relinfo, i, offset, + _("reloc has bad offset %zu"), + static_cast(offset)); + continue; } - if (sym != NULL - && sym->is_undefined() - && sym->binding() != elfcpp::STB_WEAK) + 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 +void +apply_relocation(const Relocate_info* relinfo, + Target_type* target, + typename elfcpp::Elf_types::Elf_Addr r_offset, + unsigned int r_type, + typename elfcpp::Elf_types::Elf_Swxword r_addend, + const Symbol* gsym, + unsigned char* view, + typename elfcpp::Elf_types::Elf_Addr address, + section_size_type view_size) +{ + // Construct the ELF relocation in a temporary buffer. + const int reloc_size = elfcpp::Elf_sizes::rela_size; + unsigned char relbuf[reloc_size]; + elfcpp::Rela_write orel(relbuf); + orel.put_r_offset(r_offset); + orel.put_r_info(elfcpp::elf_r_info(0, r_type)); + orel.put_r_addend(r_addend); + + // Setup a Symbol_value for the global symbol. + const Sized_symbol* sym = static_cast*>(gsym); + Symbol_value 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 +class Default_classify_reloc +{ + public: + typedef typename Reloc_types::Reloc + Reltype; + typedef typename Reloc_types::Reloc_write + Reltype_write; + static const int reloc_size = + Reloc_types::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(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(reloc->get_r_info()); } + + // Return the explicit addend of the relocation (return 0 for SHT_REL). + static inline typename elfcpp::Elf_types::Elf_Swxword + get_r_addend(const Reltype* reloc) + { return Reloc_types::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(reloc->get_r_info()); + new_reloc->put_r_info(elfcpp::elf_r_info(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::Elf_Swxword addend) + { Reloc_types::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 +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 +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 +void +scan_relocatable_relocs( + Symbol_table*, + Layout*, + Sized_relobj_file* 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::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 { - fprintf(stderr, _("%s: %s: undefined reference to '%s'\n"), - program_name, relinfo->location(i, offset).c_str(), - sym->name()); - // gold_exit(false); + 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 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); + } } - if (sym != NULL && sym->has_warning()) - relinfo->symtab->issue_warning(sym, relinfo->location(i, offset)); + 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 +void +relocate_relocs( + const Relocate_info* relinfo, + const unsigned char* prelocs, + size_t reloc_count, + Output_section* output_section, + typename elfcpp::Elf_types::Elf_Off offset_in_output_section, + unsigned char* view, + typename elfcpp::Elf_types::Elf_Addr view_address, + section_size_type view_size, + unsigned char* reloc_view, + section_size_type reloc_view_size) +{ + typedef typename elfcpp::Elf_types::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
(0) - 1; + + Sized_relobj_file* const object = relinfo->object; + const unsigned int local_count = object->local_symbol_count(); + + unsigned char* pwrite = reloc_view; + + const bool relocatable = parameters->options().relocatable(); + + 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* target = + parameters->sized_target(); + 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(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 (!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* 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::Elf_Swxword addend + = Classify_reloc::get_r_addend(&reloc); + addend = psymval->value(object, addend); + // In a relocatable link, the symbol value is relative to + // the start of the output section. For a non-relocatable + // link, we need to adjust the addend. + if (!relocatable) + { + gold_assert(os != NULL); + 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::rel8(padd, object, + psymval); + break; + + case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_2: + Relocate_functions::rel16(padd, object, + psymval); + break; + + case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4: + Relocate_functions::rel32(padd, object, + psymval); + break; + + case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_8: + Relocate_functions::rel64(padd, object, + psymval); + break; + + case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4_UNALIGNED: + Relocate_functions::rel32_unaligned(padd, + object, + psymval); + break; + + default: + gold_unreachable(); + } + } + + pwrite += reloc_size; + } + + gold_assert(static_cast(pwrite - reloc_view) + == reloc_view_size); +} + } // End namespace gold. #endif // !defined(GOLD_TARGET_RELOC_H)