X-Git-Url: http://drtracing.org/?a=blobdiff_plain;f=gold%2Ftarget-reloc.h;h=039621c50ff5145a7043800f0bf66a61c93cac6f;hb=c3d399e712774f8c8e4cd6b6a5bb8230c42bc760;hp=1cdc24458a640e4a6d04acaeda9bb046ec39a73b;hpb=9c2d0ef98abc05ea6fae35be6db732b22bba71b5;p=deliverable%2Fbinutils-gdb.git diff --git a/gold/target-reloc.h b/gold/target-reloc.h index 1cdc24458a..039621c50f 100644 --- a/gold/target-reloc.h +++ b/gold/target-reloc.h @@ -1,6 +1,7 @@ // target-reloc.h -- target specific relocation support -*- C++ -*- -// Copyright 2006, 2007, 2008 Free Software Foundation, Inc. +// Copyright 2006, 2007, 2008, 2009, 2010, 2011, 2012 +// Free Software Foundation, Inc. // Written by Ian Lance Taylor . // This file is part of gold. @@ -25,6 +26,7 @@ #include "elfcpp.h" #include "symtab.h" +#include "object.h" #include "reloc.h" #include "reloc-types.h" @@ -35,18 +37,17 @@ namespace gold // 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 -// avoidmaking a function call for each relocation, and to avoid +// avoid making a function call for each relocation, and to avoid // repeating the generic code for each target. 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, @@ -81,30 +82,25 @@ 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)) - { - // 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, data_shndx, - output_section, reloc, r_type, lsym); + // 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 { @@ -113,7 +109,7 @@ scan_relocs( if (gsym->is_forwarder()) gsym = symtab->resolve_forwards(gsym); - scan.global(options, symtab, layout, target, object, data_shndx, + scan.global(symtab, layout, target, object, data_shndx, output_section, reloc, r_type, gsym); } } @@ -129,19 +125,99 @@ enum Comdat_behavior CB_WARNING // Print a warning. }; -// 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. +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 Comdat_behavior -get_comdat_behavior(const char* name) +inline bool +issue_undefined_symbol_error(const Symbol* sym) { - 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; + // 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->binding() == elfcpp::STB_WEAK) + return false; + + // We don't report symbols defined in discarded sections. + if (sym->is_defined_in_discarded_section()) + 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; + } + + // 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. @@ -149,6 +225,11 @@ get_comdat_behavior(const char* name) // 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. @@ -163,8 +244,15 @@ get_comdat_behavior(const char* name) // 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 + typename Relocate, + typename Relocate_comdat_behavior> inline void relocate_section( const Relocate_info* relinfo, @@ -175,13 +263,15 @@ relocate_section( bool needs_special_offset_handling, unsigned char* view, typename elfcpp::Elf_types::Elf_Addr view_address, - section_size_type 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; Relocate relocate; + Relocate_comdat_behavior relocate_comdat_behavior; - Sized_relobj* object = relinfo->object; + Sized_relobj_file* object = relinfo->object; unsigned int local_count = object->local_symbol_count(); Comdat_behavior comdat_behavior = CB_UNDETERMINED; @@ -210,7 +300,11 @@ relocate_section( Symbol_value symval; const Symbol_value *psymval; - if (r_sym < local_count) + 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); @@ -218,58 +312,86 @@ 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. + // counterpart in the kept section. The symbol must not + // correspond to a section we are folding. bool is_ordinary; - unsigned int shndx = psymval->input_shndx(&is_ordinary); - if (is_ordinary - && shndx != elfcpp::SHN_UNDEF - && !object->is_section_included(shndx)) - { - if (comdat_behavior == CB_UNDETERMINED) - { - std::string name = object->section_name(relinfo->data_shndx); - comdat_behavior = get_comdat_behavior(name.c_str()); - } - if (comdat_behavior == CB_PRETEND) - { - bool found; - typename elfcpp::Elf_types::Elf_Addr value = - object->map_to_kept_section(shndx, &found); - if (found) - symval.set_output_value(value + psymval->input_value()); - else - symval.set_output_value(0); - } - else - { - if (comdat_behavior == CB_WARNING) - gold_warning_at_location(relinfo, i, offset, - _("Relocation refers to discarded " - "comdat section")); - symval.set_output_value(0); - } - symval.set_no_output_symtab_entry(); - psymval = &symval; - } + 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 = object->global_symbol(r_sym); - gold_assert(gsym != NULL); - if (gsym->is_forwarder()) - gsym = relinfo->symtab->resolve_forwards(gsym); + 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*>(gsym); - if (sym->has_symtab_index()) + 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; } - if (!relocate.relocate(relinfo, target, i, reloc, r_type, sym, psymval, - view + offset, view_address + offset, view_size)) + Symbol_value 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::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 (!relocate.relocate(relinfo, target, output_section, i, reloc, + r_type, sym, psymval, view + offset, + view_address + offset, view_size)) continue; if (offset < 0 || static_cast(offset) >= view_size) @@ -280,19 +402,58 @@ relocate_section( continue; } - if (sym != NULL - && sym->is_undefined() - && sym->binding() != elfcpp::STB_WEAK - && !target->is_defined_by_abi(sym) - && (!parameters->options().shared() // -shared - || parameters->options().defs())) // -z defs - gold_undefined_symbol(sym, relinfo, i, offset); + 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_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 rel(relbuf); + 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, target, NULL, -1U, rel, r_type, sym, &symval, + view + r_offset, address + r_offset, view_size); +} + // 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 @@ -308,8 +469,14 @@ class Default_scan_relocatable_relocs // 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, Relobj*) - { return Relocatable_relocs::RELOC_COPY; } + 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. @@ -358,10 +525,9 @@ template void scan_relocatable_relocs( - const General_options&, Symbol_table*, Layout*, - Sized_relobj* object, + Sized_relobj_file* object, unsigned int data_shndx, const unsigned char* prelocs, size_t reloc_count, @@ -413,13 +579,17 @@ scan_relocatable_relocs( strategy = Relocatable_relocs::RELOC_DISCARD; } else if (lsym.get_st_type() != elfcpp::STT_SECTION) - strategy = scan.local_non_section_strategy(r_type, object); + 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); } } @@ -427,21 +597,21 @@ scan_relocatable_relocs( } } -// Relocate relocs during a relocatable link. This is a default -// definition which should work for most targets. +// 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_for_relocatable( +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, + typename elfcpp::Elf_types::Elf_Off offset_in_output_section, const Relocatable_relocs* rr, unsigned char* view, typename elfcpp::Elf_types::Elf_Addr view_address, - section_size_type, + section_size_type view_size, unsigned char* reloc_view, section_size_type reloc_view_size) { @@ -450,8 +620,9 @@ relocate_for_relocatable( typedef typename Reloc_types::Reloc_write Reltype_write; const int reloc_size = Reloc_types::reloc_size; + const Address invalid_address = static_cast
(0) - 1; - Sized_relobj* const object = relinfo->object; + Sized_relobj_file* const object = relinfo->object; const unsigned int local_count = object->local_symbol_count(); unsigned char* pwrite = reloc_view; @@ -462,6 +633,19 @@ relocate_for_relocatable( 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, 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); @@ -477,8 +661,13 @@ relocate_for_relocatable( switch (strategy) { case Relocatable_relocs::RELOC_COPY: - new_symndx = object->symtab_index(r_sym); - gold_assert(new_symndx != -1U); + 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: @@ -487,6 +676,7 @@ relocate_for_relocatable( 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 @@ -524,7 +714,7 @@ relocate_for_relocatable( Address offset = reloc.get_r_offset(); Address new_offset; - if (offset_in_output_section != -1U) + if (offset_in_output_section != invalid_address) new_offset = offset + offset_in_output_section; else { @@ -543,7 +733,7 @@ relocate_for_relocatable( if (!parameters->options().relocatable()) { new_offset += view_address; - if (offset_in_output_section != -1U) + if (offset_in_output_section != invalid_address) new_offset -= offset_in_output_section; } @@ -608,6 +798,12 @@ relocate_for_relocatable( psymval); break; + case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4_UNALIGNED: + Relocate_functions::rel32_unaligned(padd, + object, + psymval); + break; + default: gold_unreachable(); }