X-Git-Url: http://git.efficios.com/?a=blobdiff_plain;f=gold%2Ftarget-reloc.h;h=2b205a1a74bfb7d73b26ba04d321e7735bfd5887;hb=c0b0a14290e1909a6cc3febb443560c3e95562c2;hp=96f2614f0087b7a9e73c8667ac12bd2bc2d8facc;hpb=7404fe1b8d20b30162a7e56307d5a2d400cb5645;p=deliverable%2Fbinutils-gdb.git diff --git a/gold/target-reloc.h b/gold/target-reloc.h index 96f2614f00..2b205a1a74 100644 --- a/gold/target-reloc.h +++ b/gold/target-reloc.h @@ -1,6 +1,6 @@ // target-reloc.h -- target specific relocation support -*- C++ -*- -// Copyright 2006, 2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc. +// Copyright (C) 2006-2020 Free Software Foundation, Inc. // Written by Ian Lance Taylor . // This file is part of gold. @@ -39,8 +39,8 @@ namespace gold // avoid making a function call for each relocation, and to avoid // repeating the generic code for each target. -template +template inline void scan_relocs( Symbol_table* symtab, @@ -55,8 +55,8 @@ scan_relocs( size_t local_count, 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; @@ -69,9 +69,8 @@ scan_relocs( reloc.get_r_offset())) continue; - 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); + 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) { @@ -81,30 +80,25 @@ scan_relocs( 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) - && !symtab->is_section_folded(object, 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; - } + // 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); + output_section, reloc, r_type, lsym, is_discarded); } else { @@ -126,23 +120,27 @@ 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. + CB_ERROR // Print an error. }; -// 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_comdat_behavior(const char* name) +class Default_comdat_behavior { - 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; -} + 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. @@ -185,11 +183,13 @@ issue_undefined_symbol_error(const Symbol* sym) return false; // We don't report weak symbols. - if (sym->binding() == elfcpp::STB_WEAK) + if (sym->is_weak_undefined()) return false; - // We don't report symbols defined in discarded sections. - if (sym->is_defined_in_discarded_section()) + // 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. @@ -211,6 +211,10 @@ issue_undefined_symbol_error(const Symbol* sym) 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()) @@ -220,11 +224,62 @@ issue_undefined_symbol_error(const Symbol* sym) 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. // 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. @@ -245,8 +300,10 @@ issue_undefined_symbol_error(const Symbol* sym) // symbol for the relocation, ignoring the symbol index in the // relocation. -template +template inline void relocate_section( const Relocate_info* relinfo, @@ -260,9 +317,10 @@ relocate_section( 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(); @@ -285,9 +343,7 @@ relocate_section( continue; } - 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); + unsigned int r_sym = Classify_reloc::get_r_sym(&reloc); const Sized_symbol* sym; @@ -295,6 +351,7 @@ relocate_section( 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)) @@ -305,7 +362,7 @@ relocate_section( // 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 + // 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); @@ -317,7 +374,6 @@ relocate_section( } else { - const Symbol* gsym; if (reloc_symbol_changes != NULL && (*reloc_symbol_changes)[i] != NULL) gsym = (*reloc_symbol_changes)[i]; @@ -350,11 +406,11 @@ relocate_section( Symbol_value symval2; if (is_defined_in_discarded_section) { + std::string name = object->section_name(relinfo->data_shndx); + if (comdat_behavior == CB_UNDETERMINED) - { - std::string name = object->section_name(relinfo->data_shndx); - comdat_behavior = get_comdat_behavior(name.c_str()); - } + comdat_behavior = relocate_comdat_behavior.get(name.c_str()); + if (comdat_behavior == CB_PRETEND) { // FIXME: This case does not work for global symbols. @@ -364,7 +420,7 @@ relocate_section( // script. bool found; typename elfcpp::Elf_types::Elf_Addr value = - object->map_to_kept_section(shndx, &found); + object->map_to_kept_section(shndx, name, &found); if (found) symval2.set_output_value(value + psymval->input_value()); else @@ -372,22 +428,28 @@ relocate_section( } else { - if (comdat_behavior == CB_WARNING) - gold_warning_at_location(relinfo, i, offset, - _("relocation refers to discarded " - "section")); + 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, output_section, i, reloc, - r_type, sym, psymval, 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 || static_cast(offset) >= view_size) + if (v == NULL) { gold_error_at_location(relinfo, i, offset, _("reloc has bad offset %zu"), @@ -399,7 +461,7 @@ relocate_section( gold_undefined_symbol_at_location(sym, relinfo, i, offset); else if (sym != NULL && sym->visibility() != elfcpp::STV_DEFAULT - && (sym->is_undefined() || sym->is_from_dynobj())) + && (sym->is_strong_undefined() || sym->is_from_dynobj())) visibility_error(sym); if (sym != NULL && sym->has_warning()) @@ -425,7 +487,6 @@ apply_relocation(const Relocate_info* relinfo, // Construct the ELF relocation in a temporary buffer. const int reloc_size = elfcpp::Elf_sizes::rela_size; unsigned char relbuf[reloc_size]; - elfcpp::Rela rel(relbuf); elfcpp::Rela_write orel(relbuf); orel.put_r_offset(r_offset); orel.put_r_info(elfcpp::elf_r_info(0, r_type)); @@ -443,22 +504,95 @@ apply_relocation(const Relocate_info* relinfo, symval.set_is_ifunc_symbol(); Relocate relocate; - relocate.relocate(relinfo, target, NULL, -1U, rel, r_type, sym, &symval, + 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. The -// template parameter Classify_reloc must be a class type which -// provides a function get_size_for_reloc which returns the number of -// bytes to which a reloc applies. 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 +// 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 @@ -480,8 +614,7 @@ class Default_scan_relocatable_relocs return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA; else { - Classify_reloc classify; - switch (classify.get_size_for_reloc(r_type, object)) + switch (Classify_reloc::get_size_for_reloc(r_type, object)) { case 0: return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_0; @@ -506,6 +639,56 @@ class Default_scan_relocatable_relocs { 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 @@ -514,8 +697,7 @@ class Default_scan_relocatable_relocs // local_section_strategy. Most targets should be able to use // Default_scan_relocatable_relocs as this class. -template +template void scan_relocatable_relocs( Symbol_table*, @@ -530,8 +712,8 @@ scan_relocatable_relocs( const unsigned char* plocal_syms, Relocatable_relocs* rr) { - typedef typename Reloc_types::Reloc Reltype; - const int reloc_size = Reloc_types::reloc_size; + 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; @@ -547,10 +729,9 @@ scan_relocatable_relocs( strategy = Relocatable_relocs::RELOC_DISCARD; else { - typename elfcpp::Elf_types::Elf_WXword r_info = - reloc.get_r_info(); - const unsigned int r_sym = elfcpp::elf_r_sym(r_info); - const unsigned int r_type = elfcpp::elf_r_type(r_info); + 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); @@ -593,15 +774,14 @@ scan_relocatable_relocs( // Relocate relocs. Called for a relocatable link, and for --emit-relocs. // This is a default definition which should work for most targets. -template +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_Addr offset_in_output_section, - const Relocatable_relocs* rr, + 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, @@ -609,10 +789,9 @@ relocate_relocs( section_size_type reloc_view_size) { typedef typename elfcpp::Elf_types::Elf_Addr Address; - typedef typename Reloc_types::Reloc Reltype; - typedef typename Reloc_types::Reloc_write - Reltype_write; - const int reloc_size = Reloc_types::reloc_size; + 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; @@ -620,9 +799,11 @@ relocate_relocs( 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 = rr->strategy(i); + Relocatable_relocs::Reloc_strategy strategy = relinfo->rr->strategy(i); if (strategy == Relocatable_relocs::RELOC_DISCARD) continue; @@ -631,8 +812,8 @@ relocate_relocs( // Target wants to handle this relocation. Sized_target* target = parameters->sized_target(); - target->relocate_special_relocatable(relinfo, sh_type, prelocs, - i, output_section, + target->relocate_special_relocatable(relinfo, Classify_reloc::sh_type, + prelocs, i, output_section, offset_in_output_section, view, view_address, view_size, pwrite); @@ -642,12 +823,11 @@ relocate_relocs( Reltype reloc(prelocs); Reltype_write reloc_write(pwrite); - typename elfcpp::Elf_types::Elf_WXword r_info = reloc.get_r_info(); - const unsigned int r_sym = elfcpp::elf_r_sym(r_info); - const unsigned int r_type = elfcpp::elf_r_type(r_info); + 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) { @@ -680,7 +860,7 @@ relocate_relocs( unsigned int shndx = object->local_symbol_input_shndx(r_sym, &is_ordinary); gold_assert(is_ordinary); - Output_section* os = object->output_section(shndx); + os = object->output_section(shndx); gold_assert(os != NULL); gold_assert(os->needs_symtab_index()); new_symndx = os->symtab_index(); @@ -723,7 +903,7 @@ relocate_relocs( // 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()) + if (!relocatable) { new_offset += view_address; if (offset_in_output_section != invalid_address) @@ -731,16 +911,15 @@ relocate_relocs( } reloc_write.put_r_offset(new_offset); - reloc_write.put_r_info(elfcpp::elf_r_info(new_symndx, r_type)); + 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 (sh_type == elfcpp::SHT_RELA) - Reloc_types:: - copy_reloc_addend(&reloc_write, - &reloc); + if (Classify_reloc::sh_type == elfcpp::SHT_RELA) + Classify_reloc::put_r_addend(&reloc_write, + Classify_reloc::get_r_addend(&reloc)); } else { @@ -759,12 +938,18 @@ relocate_relocs( { case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA: { - typename elfcpp::Elf_types::Elf_Swxword addend; - addend = Reloc_types:: - get_reloc_addend(&reloc); + typename elfcpp::Elf_types::Elf_Swxword addend + = Classify_reloc::get_r_addend(&reloc); addend = psymval->value(object, addend); - Reloc_types:: - set_reloc_addend(&reloc_write, 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;