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// target-reloc.h -- target specific relocation support -*- C++ -*-
// Copyright 2006, 2007 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 "reloc-types.h"
namespace gold
{
// This function implements the generic part of reloc scanning. This
// is an inline function which takes a class whose member functions
// local() and global() implement 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>
inline void
scan_relocs(
const General_options& options,
Symbol_table* symtab,
Layout* layout,
Target_type* target,
Sized_relobj<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 Reloc_types<sh_type, size, big_endian>::Reloc Reltype;
const int reloc_size = Reloc_types<sh_type, size, big_endian>::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;
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 (r_sym < local_count)
{
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, data_shndx,
reloc, r_type, lsym);
}
else
{
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, data_shndx,
reloc, r_type, gsym);
}
}
}
// This function implements the generic part of relocation processing.
// This is an inline function which take a class whose relocate()
// 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.
// 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.
template<int size, bool big_endian, typename Target_type, int sh_type,
typename Relocate>
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)
{
typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype;
const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size;
Relocate relocate;
Sized_relobj<size, big_endian>* object = relinfo->object;
unsigned int local_count = object->local_symbol_count();
for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size)
{
Reltype reloc(prelocs);
off_t offset = reloc.get_r_offset();
if (needs_special_offset_handling)
{
offset = output_section->output_offset(relinfo->object,
relinfo->data_shndx,
offset);
if (offset == -1)
continue;
}
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);
const Sized_symbol<size>* sym;
Symbol_value<size> symval;
const Symbol_value<size> *psymval;
if (r_sym < local_count)
{
sym = NULL;
psymval = object->local_symbol(r_sym);
}
else
{
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<const Sized_symbol<size>*>(gsym);
if (sym->has_symtab_index())
symval.set_output_symtab_index(sym->symtab_index());
else
symval.set_no_output_symtab_entry();
symval.set_output_value(sym->value());
psymval = &symval;
}
if (!relocate.relocate(relinfo, target, i, reloc, r_type, sym, psymval,
view + offset, view_address + offset, view_size))
continue;
if (offset < 0 || offset >= view_size)
{
gold_error_at_location(relinfo, i, offset,
_("reloc has bad offset %zu"),
static_cast<size_t>(offset));
continue;
}
if (sym != NULL
&& sym->is_undefined()
&& sym->binding() != elfcpp::STB_WEAK
&& !parameters->output_is_shared())
gold_undefined_symbol(sym, relinfo, i, offset);
if (sym != NULL && sym->has_warning())
relinfo->symtab->issue_warning(sym, relinfo, i, offset);
}
}
} // End namespace gold.
#endif // !defined(GOLD_TARGET_RELOC_H)
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