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binutils-gdb/gold/reloc.cc
Ian Lance Taylor 82bb573a56 * object.h (class Relocate_info): Add reloc_shdr and data_shdr 
fields.
	* object.cc (Sized_relobj::relocate_sections): Set reloc_shdr and
	data_shdr fields of relinfo.
	* i386.cc (class Target_i386::Relocate): Remove ldo_addrs_ field.
	(Target_i386::Relocate::relocate_tls): Don't call fix_up_ldo.  For
	R_386_TLS_LDO_32, adjust based on section flags.
	(Target_i386::Relocate::fix_up_ldo): Remove.
2009-10-15 00:33:18 +00:00

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// reloc.cc -- relocate input files for gold.
// Copyright 2006, 2007, 2008, 2009 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.
#include "gold.h"
#include <algorithm>
#include "workqueue.h"
#include "symtab.h"
#include "output.h"
#include "merge.h"
#include "object.h"
#include "target-reloc.h"
#include "reloc.h"
#include "icf.h"
namespace gold
{
// Read_relocs methods.
// These tasks just read the relocation information from the file.
// After reading it, the start another task to process the
// information. These tasks requires access to the file.
Task_token*
Read_relocs::is_runnable()
{
return this->object_->is_locked() ? this->object_->token() : NULL;
}
// Lock the file.
void
Read_relocs::locks(Task_locker* tl)
{
tl->add(this, this->object_->token());
}
// Read the relocations and then start a Scan_relocs_task.
void
Read_relocs::run(Workqueue* workqueue)
{
Read_relocs_data *rd = new Read_relocs_data;
this->object_->read_relocs(rd);
this->object_->set_relocs_data(rd);
this->object_->release();
// If garbage collection or identical comdat folding is desired, we
// process the relocs first before scanning them. Scanning of relocs is
// done only after garbage or identical sections is identified.
if (parameters->options().gc_sections()
|| parameters->options().icf_enabled())
{
workqueue->queue_next(new Gc_process_relocs(this->options_,
this->symtab_,
this->layout_,
this->object_, rd,
this->symtab_lock_,
this->blocker_));
}
else
{
workqueue->queue_next(new Scan_relocs(this->options_, this->symtab_,
this->layout_, this->object_, rd,
this->symtab_lock_,
this->blocker_));
}
}
// Return a debugging name for the task.
std::string
Read_relocs::get_name() const
{
return "Read_relocs " + this->object_->name();
}
// Gc_process_relocs methods.
// These tasks process the relocations read by Read_relocs and
// determine which sections are referenced and which are garbage.
// This task is done only when --gc-sections is used.
Task_token*
Gc_process_relocs::is_runnable()
{
if (this->object_->is_locked())
return this->object_->token();
return NULL;
}
void
Gc_process_relocs::locks(Task_locker* tl)
{
tl->add(this, this->object_->token());
tl->add(this, this->blocker_);
}
void
Gc_process_relocs::run(Workqueue*)
{
this->object_->gc_process_relocs(this->options_, this->symtab_, this->layout_,
this->rd_);
this->object_->release();
}
// Return a debugging name for the task.
std::string
Gc_process_relocs::get_name() const
{
return "Gc_process_relocs " + this->object_->name();
}
// Scan_relocs methods.
// These tasks scan the relocations read by Read_relocs and mark up
// the symbol table to indicate which relocations are required. We
// use a lock on the symbol table to keep them from interfering with
// each other.
Task_token*
Scan_relocs::is_runnable()
{
if (!this->symtab_lock_->is_writable())
return this->symtab_lock_;
if (this->object_->is_locked())
return this->object_->token();
return NULL;
}
// Return the locks we hold: one on the file, one on the symbol table
// and one blocker.
void
Scan_relocs::locks(Task_locker* tl)
{
tl->add(this, this->object_->token());
tl->add(this, this->symtab_lock_);
tl->add(this, this->blocker_);
}
// Scan the relocs.
void
Scan_relocs::run(Workqueue*)
{
this->object_->scan_relocs(this->options_, this->symtab_, this->layout_,
this->rd_);
this->object_->release();
delete this->rd_;
this->rd_ = NULL;
}
// Return a debugging name for the task.
std::string
Scan_relocs::get_name() const
{
return "Scan_relocs " + this->object_->name();
}
// Relocate_task methods.
// We may have to wait for the output sections to be written.
Task_token*
Relocate_task::is_runnable()
{
if (this->object_->relocs_must_follow_section_writes()
&& this->output_sections_blocker_->is_blocked())
return this->output_sections_blocker_;
if (this->object_->is_locked())
return this->object_->token();
return NULL;
}
// We want to lock the file while we run. We want to unblock
// INPUT_SECTIONS_BLOCKER and FINAL_BLOCKER when we are done.
// INPUT_SECTIONS_BLOCKER may be NULL.
void
Relocate_task::locks(Task_locker* tl)
{
if (this->input_sections_blocker_ != NULL)
tl->add(this, this->input_sections_blocker_);
tl->add(this, this->final_blocker_);
tl->add(this, this->object_->token());
}
// Run the task.
void
Relocate_task::run(Workqueue*)
{
this->object_->relocate(this->options_, this->symtab_, this->layout_,
this->of_);
// This is normally the last thing we will do with an object, so
// uncache all views.
this->object_->clear_view_cache_marks();
this->object_->release();
}
// Return a debugging name for the task.
std::string
Relocate_task::get_name() const
{
return "Relocate_task " + this->object_->name();
}
// Read the relocs and local symbols from the object file and store
// the information in RD.
template<int size, bool big_endian>
void
Sized_relobj<size, big_endian>::do_read_relocs(Read_relocs_data* rd)
{
rd->relocs.clear();
unsigned int shnum = this->shnum();
if (shnum == 0)
return;
rd->relocs.reserve(shnum / 2);
const Output_sections& out_sections(this->output_sections());
const std::vector<Address>& out_offsets(this->section_offsets_);
const unsigned char *pshdrs = this->get_view(this->elf_file_.shoff(),
shnum * This::shdr_size,
true, true);
// Skip the first, dummy, section.
const unsigned char *ps = pshdrs + This::shdr_size;
for (unsigned int i = 1; i < shnum; ++i, ps += This::shdr_size)
{
typename This::Shdr shdr(ps);
unsigned int sh_type = shdr.get_sh_type();
if (sh_type != elfcpp::SHT_REL && sh_type != elfcpp::SHT_RELA)
continue;
unsigned int shndx = this->adjust_shndx(shdr.get_sh_info());
if (shndx >= shnum)
{
this->error(_("relocation section %u has bad info %u"),
i, shndx);
continue;
}
Output_section* os = out_sections[shndx];
if (os == NULL)
continue;
// We are scanning relocations in order to fill out the GOT and
// PLT sections. Relocations for sections which are not
// allocated (typically debugging sections) should not add new
// GOT and PLT entries. So we skip them unless this is a
// relocatable link or we need to emit relocations. FIXME: What
// should we do if a linker script maps a section with SHF_ALLOC
// clear to a section with SHF_ALLOC set?
typename This::Shdr secshdr(pshdrs + shndx * This::shdr_size);
bool is_section_allocated = ((secshdr.get_sh_flags() & elfcpp::SHF_ALLOC)
!= 0);
if (!is_section_allocated
&& !parameters->options().relocatable()
&& !parameters->options().emit_relocs())
continue;
if (this->adjust_shndx(shdr.get_sh_link()) != this->symtab_shndx_)
{
this->error(_("relocation section %u uses unexpected "
"symbol table %u"),
i, this->adjust_shndx(shdr.get_sh_link()));
continue;
}
off_t sh_size = shdr.get_sh_size();
unsigned int reloc_size;
if (sh_type == elfcpp::SHT_REL)
reloc_size = elfcpp::Elf_sizes<size>::rel_size;
else
reloc_size = elfcpp::Elf_sizes<size>::rela_size;
if (reloc_size != shdr.get_sh_entsize())
{
this->error(_("unexpected entsize for reloc section %u: %lu != %u"),
i, static_cast<unsigned long>(shdr.get_sh_entsize()),
reloc_size);
continue;
}
size_t reloc_count = sh_size / reloc_size;
if (static_cast<off_t>(reloc_count * reloc_size) != sh_size)
{
this->error(_("reloc section %u size %lu uneven"),
i, static_cast<unsigned long>(sh_size));
continue;
}
rd->relocs.push_back(Section_relocs());
Section_relocs& sr(rd->relocs.back());
sr.reloc_shndx = i;
sr.data_shndx = shndx;
sr.contents = this->get_lasting_view(shdr.get_sh_offset(), sh_size,
true, true);
sr.sh_type = sh_type;
sr.reloc_count = reloc_count;
sr.output_section = os;
sr.needs_special_offset_handling = out_offsets[shndx] == invalid_address;
sr.is_data_section_allocated = is_section_allocated;
}
// Read the local symbols.
gold_assert(this->symtab_shndx_ != -1U);
if (this->symtab_shndx_ == 0 || this->local_symbol_count_ == 0)
rd->local_symbols = NULL;
else
{
typename This::Shdr symtabshdr(pshdrs
+ this->symtab_shndx_ * This::shdr_size);
gold_assert(symtabshdr.get_sh_type() == elfcpp::SHT_SYMTAB);
const int sym_size = This::sym_size;
const unsigned int loccount = this->local_symbol_count_;
gold_assert(loccount == symtabshdr.get_sh_info());
off_t locsize = loccount * sym_size;
rd->local_symbols = this->get_lasting_view(symtabshdr.get_sh_offset(),
locsize, true, true);
}
}
// Process the relocs to generate mappings from source sections to referenced
// sections. This is used during garbage colletion to determine garbage
// sections.
template<int size, bool big_endian>
void
Sized_relobj<size, big_endian>::do_gc_process_relocs(const General_options& options,
Symbol_table* symtab,
Layout* layout,
Read_relocs_data* rd)
{
Sized_target<size, big_endian>* target =
parameters->sized_target<size, big_endian>();
const unsigned char* local_symbols;
if (rd->local_symbols == NULL)
local_symbols = NULL;
else
local_symbols = rd->local_symbols->data();
for (Read_relocs_data::Relocs_list::iterator p = rd->relocs.begin();
p != rd->relocs.end();
++p)
{
if (!parameters->options().relocatable())
{
// As noted above, when not generating an object file, we
// only scan allocated sections. We may see a non-allocated
// section here if we are emitting relocs.
if (p->is_data_section_allocated)
target->gc_process_relocs(options, symtab, layout, this,
p->data_shndx, p->sh_type,
p->contents->data(), p->reloc_count,
p->output_section,
p->needs_special_offset_handling,
this->local_symbol_count_,
local_symbols);
}
}
}
// Scan the relocs and adjust the symbol table. This looks for
// relocations which require GOT/PLT/COPY relocations.
template<int size, bool big_endian>
void
Sized_relobj<size, big_endian>::do_scan_relocs(const General_options& options,
Symbol_table* symtab,
Layout* layout,
Read_relocs_data* rd)
{
Sized_target<size, big_endian>* target =
parameters->sized_target<size, big_endian>();
const unsigned char* local_symbols;
if (rd->local_symbols == NULL)
local_symbols = NULL;
else
local_symbols = rd->local_symbols->data();
for (Read_relocs_data::Relocs_list::iterator p = rd->relocs.begin();
p != rd->relocs.end();
++p)
{
// When garbage collection is on, unreferenced sections are not included
// in the link that would have been included normally. This is known only
// after Read_relocs hence this check has to be done again.
if (parameters->options().gc_sections()
|| parameters->options().icf_enabled())
{
if (p->output_section == NULL)
continue;
}
if (!parameters->options().relocatable())
{
// As noted above, when not generating an object file, we
// only scan allocated sections. We may see a non-allocated
// section here if we are emitting relocs.
if (p->is_data_section_allocated)
target->scan_relocs(options, symtab, layout, this, p->data_shndx,
p->sh_type, p->contents->data(),
p->reloc_count, p->output_section,
p->needs_special_offset_handling,
this->local_symbol_count_,
local_symbols);
if (parameters->options().emit_relocs())
this->emit_relocs_scan(options, symtab, layout, local_symbols, p);
}
else
{
Relocatable_relocs* rr = this->relocatable_relocs(p->reloc_shndx);
gold_assert(rr != NULL);
rr->set_reloc_count(p->reloc_count);
target->scan_relocatable_relocs(options, symtab, layout, this,
p->data_shndx, p->sh_type,
p->contents->data(),
p->reloc_count,
p->output_section,
p->needs_special_offset_handling,
this->local_symbol_count_,
local_symbols,
rr);
}
delete p->contents;
p->contents = NULL;
}
if (rd->local_symbols != NULL)
{
delete rd->local_symbols;
rd->local_symbols = NULL;
}
}
// This is a strategy class we use when scanning for --emit-relocs.
template<int sh_type>
class Emit_relocs_strategy
{
public:
// 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 the input relocations for --emit-relocs.
template<int size, bool big_endian>
void
Sized_relobj<size, big_endian>::emit_relocs_scan(
const General_options& options,
Symbol_table* symtab,
Layout* layout,
const unsigned char* plocal_syms,
const Read_relocs_data::Relocs_list::iterator& p)
{
Relocatable_relocs* rr = this->relocatable_relocs(p->reloc_shndx);
gold_assert(rr != NULL);
rr->set_reloc_count(p->reloc_count);
if (p->sh_type == elfcpp::SHT_REL)
this->emit_relocs_scan_reltype<elfcpp::SHT_REL>(options, symtab, layout,
plocal_syms, p, rr);
else
{
gold_assert(p->sh_type == elfcpp::SHT_RELA);
this->emit_relocs_scan_reltype<elfcpp::SHT_RELA>(options, symtab,
layout, plocal_syms, p,
rr);
}
}
// Scan the input relocation for --emit-relocs, templatized on the
// type of the relocation section.
template<int size, bool big_endian>
template<int sh_type>
void
Sized_relobj<size, big_endian>::emit_relocs_scan_reltype(
const General_options& options,
Symbol_table* symtab,
Layout* layout,
const unsigned char* plocal_syms,
const Read_relocs_data::Relocs_list::iterator& p,
Relocatable_relocs* rr)
{
scan_relocatable_relocs<size, big_endian, sh_type,
Emit_relocs_strategy<sh_type> >(
options,
symtab,
layout,
this,
p->data_shndx,
p->contents->data(),
p->reloc_count,
p->output_section,
p->needs_special_offset_handling,
this->local_symbol_count_,
plocal_syms,
rr);
}
// Relocate the input sections and write out the local symbols.
template<int size, bool big_endian>
void
Sized_relobj<size, big_endian>::do_relocate(const General_options& options,
const Symbol_table* symtab,
const Layout* layout,
Output_file* of)
{
unsigned int shnum = this->shnum();
// Read the section headers.
const unsigned char* pshdrs = this->get_view(this->elf_file_.shoff(),
shnum * This::shdr_size,
true, true);
Views views;
views.resize(shnum);
// Make two passes over the sections. The first one copies the
// section data to the output file. The second one applies
// relocations.
this->write_sections(pshdrs, of, &views);
// To speed up relocations, we set up hash tables for fast lookup of
// input offsets to output addresses.
this->initialize_input_to_output_maps();
// Apply relocations.
this->relocate_sections(options, symtab, layout, pshdrs, &views);
// After we've done the relocations, we release the hash tables,
// since we no longer need them.
this->free_input_to_output_maps();
// Write out the accumulated views.
for (unsigned int i = 1; i < shnum; ++i)
{
if (views[i].view != NULL)
{
if (!views[i].is_postprocessing_view)
{
if (views[i].is_input_output_view)
of->write_input_output_view(views[i].offset,
views[i].view_size,
views[i].view);
else
of->write_output_view(views[i].offset, views[i].view_size,
views[i].view);
}
}
}
// Write out the local symbols.
this->write_local_symbols(of, layout->sympool(), layout->dynpool(),
layout->symtab_xindex(), layout->dynsym_xindex());
// We should no longer need the local symbol values.
this->clear_local_symbols();
}
// Sort a Read_multiple vector by file offset.
struct Read_multiple_compare
{
inline bool
operator()(const File_read::Read_multiple_entry& rme1,
const File_read::Read_multiple_entry& rme2) const
{ return rme1.file_offset < rme2.file_offset; }
};
// Write section data to the output file. PSHDRS points to the
// section headers. Record the views in *PVIEWS for use when
// relocating.
template<int size, bool big_endian>
void
Sized_relobj<size, big_endian>::write_sections(const unsigned char* pshdrs,
Output_file* of,
Views* pviews)
{
unsigned int shnum = this->shnum();
const Output_sections& out_sections(this->output_sections());
const std::vector<Address>& out_offsets(this->section_offsets_);
File_read::Read_multiple rm;
bool is_sorted = true;
const unsigned char* p = pshdrs + This::shdr_size;
for (unsigned int i = 1; i < shnum; ++i, p += This::shdr_size)
{
View_size* pvs = &(*pviews)[i];
pvs->view = NULL;
const Output_section* os = out_sections[i];
if (os == NULL)
continue;
Address output_offset = out_offsets[i];
typename This::Shdr shdr(p);
if (shdr.get_sh_type() == elfcpp::SHT_NOBITS)
continue;
if ((parameters->options().relocatable()
|| parameters->options().emit_relocs())
&& (shdr.get_sh_type() == elfcpp::SHT_REL
|| shdr.get_sh_type() == elfcpp::SHT_RELA)
&& (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
{
// This is a reloc section in a relocatable link or when
// emitting relocs. We don't need to read the input file.
// The size and file offset are stored in the
// Relocatable_relocs structure.
Relocatable_relocs* rr = this->relocatable_relocs(i);
gold_assert(rr != NULL);
Output_data* posd = rr->output_data();
gold_assert(posd != NULL);
pvs->offset = posd->offset();
pvs->view_size = posd->data_size();
pvs->view = of->get_output_view(pvs->offset, pvs->view_size);
pvs->address = posd->address();
pvs->is_input_output_view = false;
pvs->is_postprocessing_view = false;
continue;
}
// In the normal case, this input section is simply mapped to
// the output section at offset OUTPUT_OFFSET.
// However, if OUTPUT_OFFSET == INVALID_ADDRESS, then input data is
// handled specially--e.g., a .eh_frame section. The relocation
// routines need to check for each reloc where it should be
// applied. For this case, we need an input/output view for the
// entire contents of the section in the output file. We don't
// want to copy the contents of the input section to the output
// section; the output section contents were already written,
// and we waited for them in Relocate_task::is_runnable because
// relocs_must_follow_section_writes is set for the object.
// Regardless of which of the above cases is true, we have to
// check requires_postprocessing of the output section. If that
// is false, then we work with views of the output file
// directly. If it is true, then we work with a separate
// buffer, and the output section is responsible for writing the
// final data to the output file.
off_t output_section_offset;
Address output_section_size;
if (!os->requires_postprocessing())
{
output_section_offset = os->offset();
output_section_size = convert_types<Address, off_t>(os->data_size());
}
else
{
output_section_offset = 0;
output_section_size =
convert_types<Address, off_t>(os->postprocessing_buffer_size());
}
off_t view_start;
section_size_type view_size;
if (output_offset != invalid_address)
{
view_start = output_section_offset + output_offset;
view_size = convert_to_section_size_type(shdr.get_sh_size());
}
else
{
view_start = output_section_offset;
view_size = convert_to_section_size_type(output_section_size);
}
if (view_size == 0)
continue;
gold_assert(output_offset == invalid_address
|| output_offset + view_size <= output_section_size);
unsigned char* view;
if (os->requires_postprocessing())
{
unsigned char* buffer = os->postprocessing_buffer();
view = buffer + view_start;
if (output_offset != invalid_address)
{
off_t sh_offset = shdr.get_sh_offset();
if (!rm.empty() && rm.back().file_offset > sh_offset)
is_sorted = false;
rm.push_back(File_read::Read_multiple_entry(sh_offset,
view_size, view));
}
}
else
{
if (output_offset == invalid_address)
view = of->get_input_output_view(view_start, view_size);
else
{
view = of->get_output_view(view_start, view_size);
off_t sh_offset = shdr.get_sh_offset();
if (!rm.empty() && rm.back().file_offset > sh_offset)
is_sorted = false;
rm.push_back(File_read::Read_multiple_entry(sh_offset,
view_size, view));
}
}
pvs->view = view;
pvs->address = os->address();
if (output_offset != invalid_address)
pvs->address += output_offset;
pvs->offset = view_start;
pvs->view_size = view_size;
pvs->is_input_output_view = output_offset == invalid_address;
pvs->is_postprocessing_view = os->requires_postprocessing();
}
// Actually read the data.
if (!rm.empty())
{
if (!is_sorted)
std::sort(rm.begin(), rm.end(), Read_multiple_compare());
this->read_multiple(rm);
}
}
// Relocate section data. VIEWS points to the section data as views
// in the output file.
template<int size, bool big_endian>
void
Sized_relobj<size, big_endian>::relocate_sections(
const General_options& options,
const Symbol_table* symtab,
const Layout* layout,
const unsigned char* pshdrs,
Views* pviews)
{
unsigned int shnum = this->shnum();
Sized_target<size, big_endian>* target =
parameters->sized_target<size, big_endian>();
const Output_sections& out_sections(this->output_sections());
const std::vector<Address>& out_offsets(this->section_offsets_);
Relocate_info<size, big_endian> relinfo;
relinfo.options = &options;
relinfo.symtab = symtab;
relinfo.layout = layout;
relinfo.object = this;
const unsigned char* p = pshdrs + This::shdr_size;
for (unsigned int i = 1; i < shnum; ++i, p += This::shdr_size)
{
typename This::Shdr shdr(p);
unsigned int sh_type = shdr.get_sh_type();
if (sh_type != elfcpp::SHT_REL && sh_type != elfcpp::SHT_RELA)
continue;
off_t sh_size = shdr.get_sh_size();
if (sh_size == 0)
continue;
unsigned int index = this->adjust_shndx(shdr.get_sh_info());
if (index >= this->shnum())
{
this->error(_("relocation section %u has bad info %u"),
i, index);
continue;
}
Output_section* os = out_sections[index];
if (os == NULL)
{
// This relocation section is against a section which we
// discarded.
continue;
}
Address output_offset = out_offsets[index];
gold_assert((*pviews)[index].view != NULL);
if (parameters->options().relocatable())
gold_assert((*pviews)[i].view != NULL);
if (this->adjust_shndx(shdr.get_sh_link()) != this->symtab_shndx_)
{
gold_error(_("relocation section %u uses unexpected "
"symbol table %u"),
i, this->adjust_shndx(shdr.get_sh_link()));
continue;
}
const unsigned char* prelocs = this->get_view(shdr.get_sh_offset(),
sh_size, true, false);
unsigned int reloc_size;
if (sh_type == elfcpp::SHT_REL)
reloc_size = elfcpp::Elf_sizes<size>::rel_size;
else
reloc_size = elfcpp::Elf_sizes<size>::rela_size;
if (reloc_size != shdr.get_sh_entsize())
{
gold_error(_("unexpected entsize for reloc section %u: %lu != %u"),
i, static_cast<unsigned long>(shdr.get_sh_entsize()),
reloc_size);
continue;
}
size_t reloc_count = sh_size / reloc_size;
if (static_cast<off_t>(reloc_count * reloc_size) != sh_size)
{
gold_error(_("reloc section %u size %lu uneven"),
i, static_cast<unsigned long>(sh_size));
continue;
}
gold_assert(output_offset != invalid_address
|| this->relocs_must_follow_section_writes());
relinfo.reloc_shndx = i;
relinfo.reloc_shdr = p;
relinfo.data_shndx = index;
relinfo.data_shdr = pshdrs + index * This::shdr_size;
unsigned char* view = (*pviews)[index].view;
Address address = (*pviews)[index].address;
section_size_type view_size = (*pviews)[index].view_size;
Reloc_symbol_changes* reloc_map = NULL;
if (this->uses_split_stack() && output_offset != invalid_address)
{
typename This::Shdr data_shdr(pshdrs + index * This::shdr_size);
if ((data_shdr.get_sh_flags() & elfcpp::SHF_EXECINSTR) != 0)
this->split_stack_adjust(symtab, pshdrs, sh_type, index,
prelocs, reloc_count, view, view_size,
&reloc_map);
}
if (!parameters->options().relocatable())
{
target->relocate_section(&relinfo, sh_type, prelocs, reloc_count, os,
output_offset == invalid_address,
view, address, view_size, reloc_map);
if (parameters->options().emit_relocs())
this->emit_relocs(&relinfo, i, sh_type, prelocs, reloc_count,
os, output_offset, view, address, view_size,
(*pviews)[i].view, (*pviews)[i].view_size);
}
else
{
Relocatable_relocs* rr = this->relocatable_relocs(i);
target->relocate_for_relocatable(&relinfo, sh_type, prelocs,
reloc_count, os, output_offset, rr,
view, address, view_size,
(*pviews)[i].view,
(*pviews)[i].view_size);
}
}
}
// Emit the relocs for --emit-relocs.
template<int size, bool big_endian>
void
Sized_relobj<size, big_endian>::emit_relocs(
const Relocate_info<size, big_endian>* relinfo,
unsigned int i,
unsigned int sh_type,
const unsigned char* prelocs,
size_t reloc_count,
Output_section* output_section,
typename elfcpp::Elf_types<size>::Elf_Addr offset_in_output_section,
unsigned char* view,
typename elfcpp::Elf_types<size>::Elf_Addr address,
section_size_type view_size,
unsigned char* reloc_view,
section_size_type reloc_view_size)
{
if (sh_type == elfcpp::SHT_REL)
this->emit_relocs_reltype<elfcpp::SHT_REL>(relinfo, i, prelocs,
reloc_count, output_section,
offset_in_output_section,
view, address, view_size,
reloc_view, reloc_view_size);
else
{
gold_assert(sh_type == elfcpp::SHT_RELA);
this->emit_relocs_reltype<elfcpp::SHT_RELA>(relinfo, i, prelocs,
reloc_count, output_section,
offset_in_output_section,
view, address, view_size,
reloc_view, reloc_view_size);
}
}
// Emit the relocs for --emit-relocs, templatized on the type of the
// relocation section.
template<int size, bool big_endian>
template<int sh_type>
void
Sized_relobj<size, big_endian>::emit_relocs_reltype(
const Relocate_info<size, big_endian>* relinfo,
unsigned int i,
const unsigned char* prelocs,
size_t reloc_count,
Output_section* output_section,
typename elfcpp::Elf_types<size>::Elf_Addr offset_in_output_section,
unsigned char* view,
typename elfcpp::Elf_types<size>::Elf_Addr address,
section_size_type view_size,
unsigned char* reloc_view,
section_size_type reloc_view_size)
{
const Relocatable_relocs* rr = this->relocatable_relocs(i);
relocate_for_relocatable<size, big_endian, sh_type>(
relinfo,
prelocs,
reloc_count,
output_section,
offset_in_output_section,
rr,
view,
address,
view_size,
reloc_view,
reloc_view_size);
}
// Create merge hash tables for the local symbols. These are used to
// speed up relocations.
template<int size, bool big_endian>
void
Sized_relobj<size, big_endian>::initialize_input_to_output_maps()
{
const unsigned int loccount = this->local_symbol_count_;
for (unsigned int i = 1; i < loccount; ++i)
{
Symbol_value<size>& lv(this->local_values_[i]);
lv.initialize_input_to_output_map(this);
}
}
// Free merge hash tables for the local symbols.
template<int size, bool big_endian>
void
Sized_relobj<size, big_endian>::free_input_to_output_maps()
{
const unsigned int loccount = this->local_symbol_count_;
for (unsigned int i = 1; i < loccount; ++i)
{
Symbol_value<size>& lv(this->local_values_[i]);
lv.free_input_to_output_map();
}
}
// If an object was compiled with -fsplit-stack, this is called to
// check whether any relocations refer to functions defined in objects
// which were not compiled with -fsplit-stack. If they were, then we
// need to apply some target-specific adjustments to request
// additional stack space.
template<int size, bool big_endian>
void
Sized_relobj<size, big_endian>::split_stack_adjust(
const Symbol_table* symtab,
const unsigned char* pshdrs,
unsigned int sh_type,
unsigned int shndx,
const unsigned char* prelocs,
size_t reloc_count,
unsigned char* view,
section_size_type view_size,
Reloc_symbol_changes** reloc_map)
{
if (sh_type == elfcpp::SHT_REL)
this->split_stack_adjust_reltype<elfcpp::SHT_REL>(symtab, pshdrs, shndx,
prelocs, reloc_count,
view, view_size,
reloc_map);
else
{
gold_assert(sh_type == elfcpp::SHT_RELA);
this->split_stack_adjust_reltype<elfcpp::SHT_RELA>(symtab, pshdrs, shndx,
prelocs, reloc_count,
view, view_size,
reloc_map);
}
}
// Adjust for -fsplit-stack, templatized on the type of the relocation
// section.
template<int size, bool big_endian>
template<int sh_type>
void
Sized_relobj<size, big_endian>::split_stack_adjust_reltype(
const Symbol_table* symtab,
const unsigned char* pshdrs,
unsigned int shndx,
const unsigned char* prelocs,
size_t reloc_count,
unsigned char* view,
section_size_type view_size,
Reloc_symbol_changes** reloc_map)
{
typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype;
const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size;
size_t local_count = this->local_symbol_count();
std::vector<section_offset_type> non_split_refs;
const unsigned char* pr = prelocs;
for (size_t i = 0; i < reloc_count; ++i, pr += reloc_size)
{
Reltype reloc(pr);
typename elfcpp::Elf_types<size>::Elf_WXword r_info = reloc.get_r_info();
unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
if (r_sym < local_count)
continue;
const Symbol* gsym = this->global_symbol(r_sym);
gold_assert(gsym != NULL);
if (gsym->is_forwarder())
gsym = symtab->resolve_forwards(gsym);
// See if this relocation refers to a function defined in an
// object compiled without -fsplit-stack. Note that we don't
// care about the type of relocation--this means that in some
// cases we will ask for a large stack unnecessarily, but this
// is not fatal. FIXME: Some targets have symbols which are
// functions but are not type STT_FUNC, e.g., STT_ARM_TFUNC.
if (gsym->type() == elfcpp::STT_FUNC
&& !gsym->is_undefined()
&& gsym->source() == Symbol::FROM_OBJECT
&& !gsym->object()->uses_split_stack())
{
section_offset_type offset =
convert_to_section_size_type(reloc.get_r_offset());
non_split_refs.push_back(offset);
}
}
if (non_split_refs.empty())
return;
// At this point, every entry in NON_SPLIT_REFS indicates a
// relocation which refers to a function in an object compiled
// without -fsplit-stack. We now have to convert that list into a
// set of offsets to functions. First, we find all the functions.
Function_offsets function_offsets;
this->find_functions(pshdrs, shndx, &function_offsets);
if (function_offsets.empty())
return;
// Now get a list of the function with references to non split-stack
// code.
Function_offsets calls_non_split;
for (std::vector<section_offset_type>::const_iterator p
= non_split_refs.begin();
p != non_split_refs.end();
++p)
{
Function_offsets::const_iterator low = function_offsets.lower_bound(*p);
if (low == function_offsets.end())
--low;
else if (low->first == *p)
;
else if (low == function_offsets.begin())
continue;
else
--low;
calls_non_split.insert(*low);
}
if (calls_non_split.empty())
return;
// Now we have a set of functions to adjust. The adjustments are
// target specific. Besides changing the output section view
// however, it likes, the target may request a relocation change
// from one global symbol name to another.
for (Function_offsets::const_iterator p = calls_non_split.begin();
p != calls_non_split.end();
++p)
{
std::string from;
std::string to;
parameters->target().calls_non_split(this, shndx, p->first, p->second,
view, view_size, &from, &to);
if (!from.empty())
{
gold_assert(!to.empty());
Symbol* tosym = NULL;
// Find relocations in the relevant function which are for
// FROM.
pr = prelocs;
for (size_t i = 0; i < reloc_count; ++i, pr += reloc_size)
{
Reltype reloc(pr);
typename elfcpp::Elf_types<size>::Elf_WXword r_info =
reloc.get_r_info();
unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
if (r_sym < local_count)
continue;
section_offset_type offset =
convert_to_section_size_type(reloc.get_r_offset());
if (offset < p->first
|| (offset
>= (p->first
+ static_cast<section_offset_type>(p->second))))
continue;
const Symbol* gsym = this->global_symbol(r_sym);
if (from == gsym->name())
{
if (tosym == NULL)
{
tosym = symtab->lookup(to.c_str());
if (tosym == NULL)
{
this->error(_("could not convert call "
"to '%s' to '%s'"),
from.c_str(), to.c_str());
break;
}
}
if (*reloc_map == NULL)
*reloc_map = new Reloc_symbol_changes(reloc_count);
(*reloc_map)->set(i, tosym);
}
}
}
}
}
// Find all the function in this object defined in section SHNDX.
// Store their offsets in the section in FUNCTION_OFFSETS.
template<int size, bool big_endian>
void
Sized_relobj<size, big_endian>::find_functions(
const unsigned char* pshdrs,
unsigned int shndx,
Sized_relobj<size, big_endian>::Function_offsets* function_offsets)
{
// We need to read the symbols to find the functions. If we wanted
// to, we could cache reading the symbols across all sections in the
// object.
const unsigned int symtab_shndx = this->symtab_shndx_;
typename This::Shdr symtabshdr(pshdrs + symtab_shndx * This::shdr_size);
gold_assert(symtabshdr.get_sh_type() == elfcpp::SHT_SYMTAB);
typename elfcpp::Elf_types<size>::Elf_WXword sh_size =
symtabshdr.get_sh_size();
const unsigned char* psyms = this->get_view(symtabshdr.get_sh_offset(),
sh_size, true, true);
const int sym_size = This::sym_size;
const unsigned int symcount = sh_size / sym_size;
for (unsigned int i = 0; i < symcount; ++i, psyms += sym_size)
{
typename elfcpp::Sym<size, big_endian> isym(psyms);
// FIXME: Some targets can have functions which do not have type
// STT_FUNC, e.g., STT_ARM_TFUNC.
if (isym.get_st_type() != elfcpp::STT_FUNC
|| isym.get_st_size() == 0)
continue;
bool is_ordinary;
unsigned int sym_shndx = this->adjust_sym_shndx(i, isym.get_st_shndx(),
&is_ordinary);
if (!is_ordinary || sym_shndx != shndx)
continue;
section_offset_type value =
convert_to_section_size_type(isym.get_st_value());
section_size_type fnsize =
convert_to_section_size_type(isym.get_st_size());
(*function_offsets)[value] = fnsize;
}
}
// Class Merged_symbol_value.
template<int size>
void
Merged_symbol_value<size>::initialize_input_to_output_map(
const Relobj* object,
unsigned int input_shndx)
{
Object_merge_map* map = object->merge_map();
map->initialize_input_to_output_map<size>(input_shndx,
this->output_start_address_,
&this->output_addresses_);
}
// Get the output value corresponding to an input offset if we
// couldn't find it in the hash table.
template<int size>
typename elfcpp::Elf_types<size>::Elf_Addr
Merged_symbol_value<size>::value_from_output_section(
const Relobj* object,
unsigned int input_shndx,
typename elfcpp::Elf_types<size>::Elf_Addr input_offset) const
{
section_offset_type output_offset;
bool found = object->merge_map()->get_output_offset(NULL, input_shndx,
input_offset,
&output_offset);
// If this assertion fails, it means that some relocation was
// against a portion of an input merge section which we didn't map
// to the output file and we didn't explicitly discard. We should
// always map all portions of input merge sections.
gold_assert(found);
if (output_offset == -1)
return 0;
else
return this->output_start_address_ + output_offset;
}
// Track_relocs methods.
// Initialize the class to track the relocs. This gets the object,
// the reloc section index, and the type of the relocs. This returns
// false if something goes wrong.
template<int size, bool big_endian>
bool
Track_relocs<size, big_endian>::initialize(
Object* object,
unsigned int reloc_shndx,
unsigned int reloc_type)
{
// If RELOC_SHNDX is -1U, it means there is more than one reloc
// section for the .eh_frame section. We can't handle that case.
if (reloc_shndx == -1U)
return false;
// If RELOC_SHNDX is 0, there is no reloc section.
if (reloc_shndx == 0)
return true;
// Get the contents of the reloc section.
this->prelocs_ = object->section_contents(reloc_shndx, &this->len_, false);
if (reloc_type == elfcpp::SHT_REL)
this->reloc_size_ = elfcpp::Elf_sizes<size>::rel_size;
else if (reloc_type == elfcpp::SHT_RELA)
this->reloc_size_ = elfcpp::Elf_sizes<size>::rela_size;
else
gold_unreachable();
if (this->len_ % this->reloc_size_ != 0)
{
object->error(_("reloc section size %zu is not a multiple of "
"reloc size %d\n"),
static_cast<size_t>(this->len_),
this->reloc_size_);
return false;
}
return true;
}
// Return the offset of the next reloc, or -1 if there isn't one.
template<int size, bool big_endian>
off_t
Track_relocs<size, big_endian>::next_offset() const
{
if (this->pos_ >= this->len_)
return -1;
// Rel and Rela start out the same, so we can always use Rel to find
// the r_offset value.
elfcpp::Rel<size, big_endian> rel(this->prelocs_ + this->pos_);
return rel.get_r_offset();
}
// Return the index of the symbol referenced by the next reloc, or -1U
// if there aren't any more relocs.
template<int size, bool big_endian>
unsigned int
Track_relocs<size, big_endian>::next_symndx() const
{
if (this->pos_ >= this->len_)
return -1U;
// Rel and Rela start out the same, so we can use Rel to find the
// symbol index.
elfcpp::Rel<size, big_endian> rel(this->prelocs_ + this->pos_);
return elfcpp::elf_r_sym<size>(rel.get_r_info());
}
// Advance to the next reloc whose r_offset is greater than or equal
// to OFFSET. Return the number of relocs we skip.
template<int size, bool big_endian>
int
Track_relocs<size, big_endian>::advance(off_t offset)
{
int ret = 0;
while (this->pos_ < this->len_)
{
// Rel and Rela start out the same, so we can always use Rel to
// find the r_offset value.
elfcpp::Rel<size, big_endian> rel(this->prelocs_ + this->pos_);
if (static_cast<off_t>(rel.get_r_offset()) >= offset)
break;
++ret;
this->pos_ += this->reloc_size_;
}
return ret;
}
// Instantiate the templates we need.
#ifdef HAVE_TARGET_32_LITTLE
template
void
Sized_relobj<32, false>::do_read_relocs(Read_relocs_data* rd);
#endif
#ifdef HAVE_TARGET_32_BIG
template
void
Sized_relobj<32, true>::do_read_relocs(Read_relocs_data* rd);
#endif
#ifdef HAVE_TARGET_64_LITTLE
template
void
Sized_relobj<64, false>::do_read_relocs(Read_relocs_data* rd);
#endif
#ifdef HAVE_TARGET_64_BIG
template
void
Sized_relobj<64, true>::do_read_relocs(Read_relocs_data* rd);
#endif
#ifdef HAVE_TARGET_32_LITTLE
template
void
Sized_relobj<32, false>::do_gc_process_relocs(const General_options& options,
Symbol_table* symtab,
Layout* layout,
Read_relocs_data* rd);
#endif
#ifdef HAVE_TARGET_32_BIG
template
void
Sized_relobj<32, true>::do_gc_process_relocs(const General_options& options,
Symbol_table* symtab,
Layout* layout,
Read_relocs_data* rd);
#endif
#ifdef HAVE_TARGET_64_LITTLE
template
void
Sized_relobj<64, false>::do_gc_process_relocs(const General_options& options,
Symbol_table* symtab,
Layout* layout,
Read_relocs_data* rd);
#endif
#ifdef HAVE_TARGET_64_BIG
template
void
Sized_relobj<64, true>::do_gc_process_relocs(const General_options& options,
Symbol_table* symtab,
Layout* layout,
Read_relocs_data* rd);
#endif
#ifdef HAVE_TARGET_32_LITTLE
template
void
Sized_relobj<32, false>::do_scan_relocs(const General_options& options,
Symbol_table* symtab,
Layout* layout,
Read_relocs_data* rd);
#endif
#ifdef HAVE_TARGET_32_BIG
template
void
Sized_relobj<32, true>::do_scan_relocs(const General_options& options,
Symbol_table* symtab,
Layout* layout,
Read_relocs_data* rd);
#endif
#ifdef HAVE_TARGET_64_LITTLE
template
void
Sized_relobj<64, false>::do_scan_relocs(const General_options& options,
Symbol_table* symtab,
Layout* layout,
Read_relocs_data* rd);
#endif
#ifdef HAVE_TARGET_64_BIG
template
void
Sized_relobj<64, true>::do_scan_relocs(const General_options& options,
Symbol_table* symtab,
Layout* layout,
Read_relocs_data* rd);
#endif
#ifdef HAVE_TARGET_32_LITTLE
template
void
Sized_relobj<32, false>::do_relocate(const General_options& options,
const Symbol_table* symtab,
const Layout* layout,
Output_file* of);
#endif
#ifdef HAVE_TARGET_32_BIG
template
void
Sized_relobj<32, true>::do_relocate(const General_options& options,
const Symbol_table* symtab,
const Layout* layout,
Output_file* of);
#endif
#ifdef HAVE_TARGET_64_LITTLE
template
void
Sized_relobj<64, false>::do_relocate(const General_options& options,
const Symbol_table* symtab,
const Layout* layout,
Output_file* of);
#endif
#ifdef HAVE_TARGET_64_BIG
template
void
Sized_relobj<64, true>::do_relocate(const General_options& options,
const Symbol_table* symtab,
const Layout* layout,
Output_file* of);
#endif
#if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
template
class Merged_symbol_value<32>;
#endif
#if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
template
class Merged_symbol_value<64>;
#endif
#if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
template
class Symbol_value<32>;
#endif
#if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
template
class Symbol_value<64>;
#endif
#ifdef HAVE_TARGET_32_LITTLE
template
class Track_relocs<32, false>;
#endif
#ifdef HAVE_TARGET_32_BIG
template
class Track_relocs<32, true>;
#endif
#ifdef HAVE_TARGET_64_LITTLE
template
class Track_relocs<64, false>;
#endif
#ifdef HAVE_TARGET_64_BIG
template
class Track_relocs<64, true>;
#endif
} // End namespace gold.
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