// target-reloc.h -- target specific relocation support -*- C++ -*-
+// Copyright (C) 2006-2016 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 "object.h"
#include "symtab.h"
+#include "object.h"
+#include "reloc.h"
+#include "reloc-types.h"
namespace gold
{
-// Pick the ELF relocation accessor class and the size based on
-// SH_TYPE, which is either SHT_REL or SHT_RELA.
+// 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 sh_type, int size, bool big_endian>
-struct Reloc_types;
-
-template<int size, bool big_endian>
-struct Reloc_types<elfcpp::SHT_REL, size, big_endian>
-{
- typedef typename elfcpp::Rel<size, big_endian> Reloc;
- static const int reloc_size = elfcpp::Elf_sizes<size>::rel_size;
-};
-
-template<int size, bool big_endian>
-struct Reloc_types<elfcpp::SHT_RELA, size, big_endian>
-{
- typedef typename elfcpp::Rela<size, big_endian> Reloc;
- static const int reloc_size = elfcpp::Elf_sizes<size>::rela_size;
-};
-
-// 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.
-
-template<int size, bool big_endian, typename Target_type, int sh_type,
- typename Scan>
+template<int size, bool big_endian, typename Target_type,
+ typename Scan, typename Classify_reloc>
inline void
scan_relocs(
- const General_options& options,
Symbol_table* symtab,
Layout* layout,
Target_type* target,
- Sized_object<size, big_endian>* object,
+ 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,
- Symbol** global_syms)
+ const unsigned char* plocal_syms)
{
- typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype;
- const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size;
+ 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;
{
Reltype reloc(prelocs);
- typename elfcpp::Elf_types<size>::Elf_WXword r_info = reloc.get_r_info();
- unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
- unsigned int r_type = elfcpp::elf_r_type<size>(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<size, big_endian> 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_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.
-// 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<int size, bool big_endian, typename Target_type, int sh_type,
- typename Relocate>
+// 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,
- off_t view_size)
+ section_size_type view_size,
+ const Reloc_symbol_changes* reloc_symbol_changes)
{
- typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype;
- const int reloc_size = Reloc_types<sh_type, size, big_endian>::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<size, big_endian>* object = relinfo->object;
+ unsigned int local_count = object->local_symbol_count();
- unsigned int local_count = relinfo->local_symbol_count;
- typename elfcpp::Elf_types<size>::Elf_Addr *local_values = relinfo->values;
- Symbol** 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<size>::Elf_WXword r_info = reloc.get_r_info();
- unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
- unsigned int r_type = elfcpp::elf_r_type<size>(r_info);
+ if (needs_special_offset_handling)
+ {
+ offset = output_section->output_offset(relinfo->object,
+ relinfo->data_shndx,
+ offset);
+ if (offset == -1)
+ continue;
+ }
- Sized_symbol<size>* sym;
- typename elfcpp::Elf_types<size>::Elf_Addr value;
+ unsigned int r_sym = Classify_reloc::get_r_sym(&reloc);
- if (r_sym < local_count)
+ 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;
- 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;
+ 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
{
- Symbol* gsym = global_syms[r_sym - local_count];
- assert(gsym != NULL);
+ const Symbol* gsym = object->global_symbol(r_sym);
+ gold_assert(gsym != NULL);
if (gsym->is_forwarder())
gsym = relinfo->symtab->resolve_forwards(gsym);
- sym = static_cast<Sized_symbol<size>*>(gsym);
- value = sym->value();
+ gold_assert(gsym->has_symtab_index());
+ new_symndx = gsym->symtab_index();
}
- if (!relocate.relocate(relinfo, target, i, reloc, r_type, sym, value,
- view + offset, view_address + offset, view_size))
- continue;
+ // 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;
+ }
- if (offset < 0 || offset >= view_size)
+ // 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())
{
- fprintf(stderr, _("%s: %s: reloc has bad offset %zu\n"),
- program_name, relinfo->location(i, offset).c_str(),
- static_cast<size_t>(offset));
- gold_exit(false);
+ new_offset += view_address;
+ if (offset_in_output_section != invalid_address)
+ new_offset -= offset_in_output_section;
}
- if (sym != NULL
- && sym->is_undefined()
- && sym->binding() != elfcpp::STB_WEAK)
+ 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
{
- fprintf(stderr, _("%s: %s: undefined reference to '%s'\n"),
- program_name, relinfo->location(i, offset).c_str(),
- sym->name());
- // gold_exit(false);
+ // 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.