// target-reloc.h -- target specific relocation support -*- C++ -*-
// Copyright (C) 2006-2020 Free Software Foundation, Inc.
// Written by Ian Lance Taylor <iant@google.com>.
// This file is part of gold.
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 3 of the License, or
// (at your option) any later version.
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
// MA 02110-1301, USA.
#ifndef GOLD_TARGET_RELOC_H
#define GOLD_TARGET_RELOC_H
#include "elfcpp.h"
#include "symtab.h"
#include "object.h"
#include "reloc.h"
#include "reloc-types.h"
namespace gold
{
// This function implements the generic part of reloc scanning. The
// template parameter Scan must be a class type which provides two
// functions: local() and global(). Those functions implement the
// machine specific part of scanning. We do it this way to
// avoid making a function call for each relocation, and to avoid
// repeating the generic code for each target.
template<int size, bool big_endian, typename Target_type,
typename Scan, typename Classify_reloc>
inline void
scan_relocs(
Symbol_table* symtab,
Layout* layout,
Target_type* target,
Sized_relobj_file<size, big_endian>* object,
unsigned int data_shndx,
const unsigned char* prelocs,
size_t reloc_count,
Output_section* output_section,
bool needs_special_offset_handling,
size_t local_count,
const unsigned char* plocal_syms)
{
typedef typename Classify_reloc::Reltype Reltype;
const int reloc_size = Classify_reloc::reloc_size;
const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
Scan scan;
for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size)
{
Reltype reloc(prelocs);
if (needs_special_offset_handling
&& !output_section->is_input_address_mapped(object, data_shndx,
reloc.get_r_offset()))
continue;
unsigned int r_sym = Classify_reloc::get_r_sym(&reloc);
unsigned int r_type = Classify_reloc::get_r_type(&reloc);
if (r_sym < local_count)
{
gold_assert(plocal_syms != NULL);
typename elfcpp::Sym<size, big_endian> lsym(plocal_syms
+ r_sym * sym_size);
unsigned int shndx = lsym.get_st_shndx();
bool is_ordinary;
shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary);
// If RELOC is a relocation against a local symbol in a
// section we are discarding then we can ignore it. It will
// eventually become a reloc against the value zero.
//
// FIXME: We should issue a warning if this is an
// allocated section; is this the best place to do it?
//
// FIXME: The old GNU linker would in some cases look
// for the linkonce section which caused this section to
// be discarded, and, if the other section was the same
// size, change the reloc to refer to the other section.
// That seems risky and weird to me, and I don't know of
// any case where it is actually required.
bool is_discarded = (is_ordinary
&& shndx != elfcpp::SHN_UNDEF
&& !object->is_section_included(shndx)
&& !symtab->is_section_folded(object, shndx));
scan.local(symtab, layout, target, object, data_shndx,
output_section, reloc, r_type, lsym, is_discarded);
}
else
{
Symbol* gsym = object->global_symbol(r_sym);
gold_assert(gsym != NULL);
if (gsym->is_forwarder())
gsym = symtab->resolve_forwards(gsym);
scan.global(symtab, layout, target, object, data_shndx,
output_section, reloc, r_type, gsym);
}
}
}
// Behavior for relocations to discarded comdat sections.
enum Comdat_behavior
{
CB_UNDETERMINED, // Not yet determined -- need to look at section name.
CB_PRETEND, // Attempt to map to the corresponding kept section.
CB_IGNORE, // Ignore the relocation.
CB_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
|| is_prefix_of (".gnu.build.attributes", name)
|| 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<int size, bool big_endian>
inline void
issue_discarded_error(
const Relocate_info<size, big_endian>* relinfo,
size_t shndx,
section_offset_type offset,
unsigned int r_sym,
const Symbol* gsym)
{
Sized_relobj_file<size, big_endian>* 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<size>::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 = 0;
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.
// PRELOCS points to the relocation data. RELOC_COUNT is the number
// of relocs. OUTPUT_SECTION is the output section.
// NEEDS_SPECIAL_OFFSET_HANDLING is true if input offsets need to be
// mapped to output offsets.
// VIEW is the section data, VIEW_ADDRESS is its memory address, and
// VIEW_SIZE is the size. These refer to the input section, unless
// NEEDS_SPECIAL_OFFSET_HANDLING is true, in which case they refer to
// the output section.
// RELOC_SYMBOL_CHANGES is used for -fsplit-stack support. If it is
// not NULL, it is a vector indexed by relocation index. If that
// entry is not NULL, it points to a global symbol which used as the
// symbol for the relocation, ignoring the symbol index in the
// relocation.
template<int size, bool big_endian, typename Target_type,
typename Relocate,
typename Relocate_comdat_behavior,
typename Classify_reloc>
inline void
relocate_section(
const Relocate_info<size, big_endian>* relinfo,
Target_type* target,
const unsigned char* prelocs,
size_t reloc_count,
Output_section* output_section,
bool needs_special_offset_handling,
unsigned char* view,
typename elfcpp::Elf_types<size>::Elf_Addr view_address,
section_size_type view_size,
const Reloc_symbol_changes* reloc_symbol_changes)
{
typedef typename Classify_reloc::Reltype Reltype;
const int reloc_size = Classify_reloc::reloc_size;
Relocate relocate;
Relocate_comdat_behavior relocate_comdat_behavior;
Sized_relobj_file<size, big_endian>* object = relinfo->object;
unsigned int local_count = object->local_symbol_count();
Comdat_behavior comdat_behavior = CB_UNDETERMINED;
for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size)
{
Reltype reloc(prelocs);
section_offset_type offset =
convert_to_section_size_type(reloc.get_r_offset());
if (needs_special_offset_handling)
{
offset = output_section->output_offset(relinfo->object,
relinfo->data_shndx,
offset);
if (offset == -1)
continue;
}
unsigned int r_sym = Classify_reloc::get_r_sym(&reloc);
const Sized_symbol<size>* sym;
Symbol_value<size> symval;
const Symbol_value<size> *psymval;
bool is_defined_in_discarded_section;
unsigned int shndx;
const Symbol* gsym = NULL;
if (r_sym < local_count
&& (reloc_symbol_changes == NULL
|| (*reloc_symbol_changes)[i] == NULL))
{
sym = NULL;
psymval = object->local_symbol(r_sym);
// If the local symbol belongs to a section we are discarding,
// and that section is a debug section, try to find the
// corresponding kept section and map this symbol to its
// counterpart in the kept section. The symbol must not
// correspond to a section we are folding.
bool is_ordinary;
shndx = psymval->input_shndx(&is_ordinary);
is_defined_in_discarded_section =
(is_ordinary
&& shndx != elfcpp::SHN_UNDEF
&& !object->is_section_included(shndx)
&& !relinfo->symtab->is_section_folded(object, shndx));
}
else
{
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)
{
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<size>::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 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;
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<size, big_endian>* target =
parameters->sized_target<size, big_endian>();
target->relocate_special_relocatable(relinfo, Classify_reloc::sh_type,
prelocs, i, output_section,
offset_in_output_section,
view, view_address,
view_size, pwrite);
pwrite += reloc_size;
continue;
}
Reltype reloc(prelocs);
Reltype_write reloc_write(pwrite);
const unsigned int r_sym = Classify_reloc::get_r_sym(&reloc);
// Get the new symbol index.
Output_section* os = NULL;
unsigned int new_symndx;
if (r_sym < local_count)
{
switch (strategy)
{
case Relocatable_relocs::RELOC_COPY:
if (r_sym == 0)
new_symndx = 0;
else
{
new_symndx = object->symtab_index(r_sym);
gold_assert(new_symndx != -1U);
}
break;
case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA:
case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_0:
case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_1:
case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_2:
case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4:
case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_8:
case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4_UNALIGNED:
{
// We are adjusting a section symbol. We need to find
// the symbol table index of the section symbol for
// the output section corresponding to input section
// in which this symbol is defined.
gold_assert(r_sym < local_count);
bool is_ordinary;
unsigned int shndx =
object->local_symbol_input_shndx(r_sym, &is_ordinary);
gold_assert(is_ordinary);
os = object->output_section(shndx);
gold_assert(os != NULL);
gold_assert(os->needs_symtab_index());
new_symndx = os->symtab_index();
}
break;
default:
gold_unreachable();
}
}
else
{
const Symbol* gsym = object->global_symbol(r_sym);
gold_assert(gsym != NULL);
if (gsym->is_forwarder())
gsym = relinfo->symtab->resolve_forwards(gsym);
gold_assert(gsym->has_symtab_index());
new_symndx = gsym->symtab_index();
}
// Get the new offset--the location in the output section where
// this relocation should be applied.
Address offset = reloc.get_r_offset();
Address new_offset;
if (offset_in_output_section != invalid_address)
new_offset = offset + offset_in_output_section;
else
{
section_offset_type sot_offset =
convert_types<section_offset_type, Address>(offset);
section_offset_type new_sot_offset =
output_section->output_offset(object, relinfo->data_shndx,
sot_offset);
gold_assert(new_sot_offset != -1);
new_offset = new_sot_offset;
}
// In an object file, r_offset is an offset within the section.
// In an executable or dynamic object, generated by
// --emit-relocs, r_offset is an absolute address.
if (!relocatable)
{
new_offset += view_address;
if (offset_in_output_section != invalid_address)
new_offset -= offset_in_output_section;
}
reloc_write.put_r_offset(new_offset);
Classify_reloc::put_r_info(&reloc_write, &reloc, new_symndx);
// Handle the reloc addend based on the strategy.
if (strategy == Relocatable_relocs::RELOC_COPY)
{
if (Classify_reloc::sh_type == elfcpp::SHT_RELA)
Classify_reloc::put_r_addend(&reloc_write,
Classify_reloc::get_r_addend(&reloc));
}
else
{
// The relocation uses a section symbol in the input file.
// We are adjusting it to use a section symbol in the output
// file. The input section symbol refers to some address in
// the input section. We need the relocation in the output
// file to refer to that same address. This adjustment to
// the addend is the same calculation we use for a simple
// absolute relocation for the input section symbol.
const Symbol_value<size>* psymval = object->local_symbol(r_sym);
unsigned char* padd = view + offset;
switch (strategy)
{
case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA:
{
typename elfcpp::Elf_types<size>::Elf_Swxword addend
= 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<size, big_endian>::rel8(padd, object,
psymval);
break;
case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_2:
Relocate_functions<size, big_endian>::rel16(padd, object,
psymval);
break;
case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4:
Relocate_functions<size, big_endian>::rel32(padd, object,
psymval);
break;
case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_8:
Relocate_functions<size, big_endian>::rel64(padd, object,
psymval);
break;
case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4_UNALIGNED:
Relocate_functions<size, big_endian>::rel32_unaligned(padd,
object,
psymval);
break;
default:
gold_unreachable();
}
}
pwrite += reloc_size;
}
gold_assert(static_cast<section_size_type>(pwrite - reloc_view)
== reloc_view_size);
}
} // End namespace gold.
#endif // !defined(GOLD_TARGET_RELOC_H)