[deliverable/binutils-gdb.git] / gold / gc.h

// gc.h -- garbage collection of unused sections

// Copyright 2009, 2010, 2011, 2012 Free Software Foundation, Inc.
// Written by Sriraman Tallam <tmsriram@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_GC_H
#define GOLD_GC_H

#include <queue>
#include <vector>

#include "elfcpp.h"
#include "symtab.h"
#include "object.h"
#include "icf.h"

namespace gold
{

class Object;

template<int size, bool big_endian>
class Sized_relobj_file;

template<int sh_type, int size, bool big_endian>
struct Reloc_types;

class Output_section;
class General_options;
class Layout;

class Garbage_collection
{
 public:

  typedef Unordered_set<Section_id, Section_id_hash> Sections_reachable;
  typedef std::map<Section_id, Sections_reachable> Section_ref;
  typedef std::queue<Section_id> Worklist_type;
  // This maps the name of the section which can be represented as a C
  // identifier (cident) to the list of sections that have that name.
  // Different object files can have cident sections with the same name.
  typedef std::map<std::string, Sections_reachable> Cident_section_map;

  Garbage_collection()
  : is_worklist_ready_(false)
  { }

  // Accessor methods for the private members.

  Sections_reachable&
  referenced_list()
  { return referenced_list_; }

  Section_ref&
  section_reloc_map()
  { return this->section_reloc_map_; }

  Worklist_type&
  worklist()
  { return this->work_list_; }

  bool
  is_worklist_ready()
  { return this->is_worklist_ready_; }

  void
  worklist_ready()
  { this->is_worklist_ready_ = true; }

  void
  do_transitive_closure();

  bool
  is_section_garbage(Object* obj, unsigned int shndx)
  { return (this->referenced_list().find(Section_id(obj, shndx))
            == this->referenced_list().end()); }

  Cident_section_map*
  cident_sections()
  { return &cident_sections_; }

  void
  add_cident_section(std::string section_name,
		     Section_id secn)
  { this->cident_sections_[section_name].insert(secn); }

  // Add a reference from the SRC_SHNDX-th section of SRC_OBJECT to
  // DST_SHNDX-th section of DST_OBJECT.
  void
  add_reference(Object* src_object, unsigned int src_shndx,
		Object* dst_object, unsigned int dst_shndx)
  {
    Section_id src_id(src_object, src_shndx);
    Section_id dst_id(dst_object, dst_shndx);
    Section_ref::iterator p = this->section_reloc_map_.find(src_id);
    if (p == this->section_reloc_map_.end())
      this->section_reloc_map_[src_id].insert(dst_id);
    else
      p->second.insert(dst_id);
  }

 private:

  Worklist_type work_list_;
  bool is_worklist_ready_;
  Section_ref section_reloc_map_;
  Sections_reachable referenced_list_;
  Cident_section_map cident_sections_;
};

// Data to pass between successive invocations of do_layout
// in object.cc while garbage collecting.  This data structure
// is filled by using the data from Read_symbols_data.

struct Symbols_data
{
  // Section headers.
  unsigned char* section_headers_data;
  // Section names.
  unsigned char* section_names_data;
  // Size of section name data in bytes.
  section_size_type section_names_size;
  // Symbol data.
  unsigned char* symbols_data;
  // Size of symbol data in bytes.
  section_size_type symbols_size;
  // Offset of external symbols within symbol data.  This structure
  // sometimes contains only external symbols, in which case this will
  // be zero.  Sometimes it contains all symbols.
  section_offset_type external_symbols_offset;
  // Symbol names.
  unsigned char* symbol_names_data;
  // Size of symbol name data in bytes.
  section_size_type symbol_names_size;
};

// Relocations of type SHT_REL store the addend value in their bytes.
// This function returns the size of the embedded addend which is
// nothing but the size of the relocation.

template<typename Classify_reloc>
inline unsigned int
get_embedded_addend_size(int sh_type, int r_type, Relobj* obj)
{
  if (sh_type != elfcpp::SHT_REL)
    return 0;
  Classify_reloc classify_reloc;
  return classify_reloc.get_size_for_reloc(r_type, obj);
}

// This function implements the generic part of reloc
// processing to map a section to all the sections it
// references through relocs.  It is called only during
// garbage collection (--gc-sections) and identical code
// folding (--icf).

template<int size, bool big_endian, typename Target_type, int sh_type,
	 typename Scan, typename Classify_reloc>
inline void
gc_process_relocs(
    Symbol_table* symtab,
    Layout*,
    Target_type* target,
    Sized_relobj_file<size, big_endian>* src_obj,
    unsigned int src_indx,
    const unsigned char* prelocs,
    size_t reloc_count,
    Output_section*,
    bool,
    size_t local_count,
    const unsigned char* plocal_syms)
{
  Object* dst_obj;
  unsigned int dst_indx;
  Scan scan;

  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;

  Icf::Sections_reachable_info* secvec = NULL;
  Icf::Symbol_info* symvec = NULL;
  Icf::Addend_info* addendvec = NULL;
  Icf::Offset_info* offsetvec = NULL;
  Icf::Reloc_addend_size_info* reloc_addend_size_vec = NULL;
  bool is_icf_tracked = false;
  const char* cident_section_name = NULL;

  std::string src_section_name = (parameters->options().icf_enabled()
                                  ? src_obj->section_name(src_indx)
                                  : "");

  bool check_section_for_function_pointers = false;

  if (parameters->options().icf_enabled()
      && is_section_foldable_candidate(src_section_name.c_str()))
    {
      is_icf_tracked = true;
      Section_id src_id(src_obj, src_indx);
      Icf::Reloc_info* reloc_info =
        &symtab->icf()->reloc_info_list()[src_id];
      secvec = &reloc_info->section_info;
      symvec = &reloc_info->symbol_info;
      addendvec = &reloc_info->addend_info;
      offsetvec = &reloc_info->offset_info;
      reloc_addend_size_vec = &reloc_info->reloc_addend_size_info;
    }

  check_section_for_function_pointers =
    symtab->icf()->check_section_for_function_pointers(src_section_name,
                                                       target);

  for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size)
    {
      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);
      typename elfcpp::Elf_types<size>::Elf_Swxword addend =
      Reloc_types<sh_type, size, big_endian>::get_reloc_addend_noerror(&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 = src_obj->adjust_sym_shndx(r_sym, shndx, &is_ordinary);
          dst_obj = src_obj;
          dst_indx = shndx;
          if (is_icf_tracked)
            {
	      if (is_ordinary) 
                (*secvec).push_back(Section_id(dst_obj, dst_indx));
	      else
                (*secvec).push_back(Section_id(NULL, 0));
              (*symvec).push_back(NULL);
              long long symvalue = static_cast<long long>(lsym.get_st_value());
              (*addendvec).push_back(std::make_pair(symvalue,
                                              static_cast<long long>(addend)));
              uint64_t reloc_offset =
                convert_to_section_size_type(reloc.get_r_offset());
	      (*offsetvec).push_back(reloc_offset);
              (*reloc_addend_size_vec).push_back(
                get_embedded_addend_size<Classify_reloc>(sh_type, r_type,
                                                         src_obj));
            }

	  // When doing safe folding, check to see if this relocation is that
	  // of a function pointer being taken.
	  if (is_ordinary
	      && check_section_for_function_pointers
              && lsym.get_st_type() != elfcpp::STT_OBJECT
 	      && scan.local_reloc_may_be_function_pointer(symtab, NULL, NULL,
							  src_obj, src_indx,
			                       		  NULL, reloc, r_type,
							  lsym))
            symtab->icf()->set_section_has_function_pointers(
              src_obj, lsym.get_st_shndx());

          if (!is_ordinary || shndx == src_indx)
            continue;
        }
      else
        {
          Symbol* gsym = src_obj->global_symbol(r_sym);
          gold_assert(gsym != NULL);
          if (gsym->is_forwarder())
            gsym = symtab->resolve_forwards(gsym);

          dst_obj = NULL;
          dst_indx = 0;
          bool is_ordinary = false;
          if (gsym->source() == Symbol::FROM_OBJECT)
            {
              dst_obj = gsym->object();
              dst_indx = gsym->shndx(&is_ordinary);
            }

	  // When doing safe folding, check to see if this relocation is that
	  // of a function pointer being taken.
	  if (gsym->source() == Symbol::FROM_OBJECT
              && check_section_for_function_pointers
              && gsym->type() != elfcpp::STT_OBJECT
              && (!is_ordinary
                  || scan.global_reloc_may_be_function_pointer(
                       symtab, NULL, NULL, src_obj, src_indx, NULL, reloc,
                       r_type, gsym)))
            symtab->icf()->set_section_has_function_pointers(dst_obj, dst_indx);

          // If the symbol name matches '__start_XXX' then the section with
          // the C identifier like name 'XXX' should not be garbage collected.
          // A similar treatment to symbols with the name '__stop_XXX'.
          if (is_prefix_of(cident_section_start_prefix, gsym->name()))
            {
              cident_section_name = (gsym->name() 
                                     + strlen(cident_section_start_prefix));
            }
          else if (is_prefix_of(cident_section_stop_prefix, gsym->name()))
            {
              cident_section_name = (gsym->name() 
                                     + strlen(cident_section_stop_prefix));
            }
          if (is_icf_tracked)
            {
              if (is_ordinary && gsym->source() == Symbol::FROM_OBJECT)
                (*secvec).push_back(Section_id(dst_obj, dst_indx));
	      else
                (*secvec).push_back(Section_id(NULL, 0));
              (*symvec).push_back(gsym);
              Sized_symbol<size>* sized_gsym =
                        static_cast<Sized_symbol<size>* >(gsym);
              long long symvalue =
                        static_cast<long long>(sized_gsym->value());
              (*addendvec).push_back(std::make_pair(symvalue,
                                        static_cast<long long>(addend)));
              uint64_t reloc_offset =
                convert_to_section_size_type(reloc.get_r_offset());
	      (*offsetvec).push_back(reloc_offset);
              (*reloc_addend_size_vec).push_back(
                get_embedded_addend_size<Classify_reloc>(sh_type, r_type,
                                                         src_obj));
	    }

          if (gsym->source() != Symbol::FROM_OBJECT)
            continue;
          if (!is_ordinary)
            continue;
        }
      if (parameters->options().gc_sections())
        {
	  symtab->gc()->add_reference(src_obj, src_indx, dst_obj, dst_indx);
          if (cident_section_name != NULL)
            {
              Garbage_collection::Cident_section_map::iterator ele =
                symtab->gc()->cident_sections()->find(std::string(cident_section_name));
              if (ele == symtab->gc()->cident_sections()->end())
                continue;
	      Section_id src_id(src_obj, src_indx);
              Garbage_collection::Sections_reachable&
                v(symtab->gc()->section_reloc_map()[src_id]);
              Garbage_collection::Sections_reachable& cident_secn(ele->second);
              for (Garbage_collection::Sections_reachable::iterator it_v
                     = cident_secn.begin();
                   it_v != cident_secn.end();
                   ++it_v)
                {
                  v.insert(*it_v);
                }
            }
        }
    }
  return;
}

} // End of namespace gold.

#endif
Commit	Line	Data
6d03d481 ST	1	// gc.h -- garbage collection of unused sections
6d03d481 ST	2
2c54b4f4	3	// Copyright 2009, 2010, 2011, 2012 Free Software Foundation, Inc.
6d03d481 ST	4	// Written by Sriraman Tallam <tmsriram@google.com>.
	5
	6	// This file is part of gold.
	7
	8	// This program is free software; you can redistribute it and/or modify
	9	// it under the terms of the GNU General Public License as published by
	10	// the Free Software Foundation; either version 3 of the License, or
	11	// (at your option) any later version.
	12
	13	// This program is distributed in the hope that it will be useful,
	14	// but WITHOUT ANY WARRANTY; without even the implied warranty of
	15	// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	16	// GNU General Public License for more details.
	17
	18	// You should have received a copy of the GNU General Public License
	19	// along with this program; if not, write to the Free Software
	20	// Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
	21	// MA 02110-1301, USA.
	22
	23	#ifndef GOLD_GC_H
	24	#define GOLD_GC_H
	25
	26	#include <queue>
ef15dade	27	#include <vector>
6d03d481 ST	28
	29	#include "elfcpp.h"
	30	#include "symtab.h"
5ac169d4	31	#include "object.h"
f345227a	32	#include "icf.h"
6d03d481 ST	33
	34	namespace gold
	35	{
	36
	37	class Object;
	38
	39	template<int size, bool big_endian>
6fa2a40b	40	class Sized_relobj_file;
6d03d481 ST	41
6d03d481 ST	42	template<int sh_type, int size, bool big_endian>
2c54b4f4	43	struct Reloc_types;
6d03d481 ST	44
	45	class Output_section;
	46	class General_options;
	47	class Layout;
	48
6d03d481 ST	49	class Garbage_collection
6d03d481 ST	50	{
ef15dade ST	51	public:
ef15dade ST	52
6d03d481 ST	53	typedef Unordered_set<Section_id, Section_id_hash> Sections_reachable;
	54	typedef std::map<Section_id, Sections_reachable> Section_ref;
	55	typedef std::queue<Section_id> Worklist_type;
f1ec9ded ST	56	// This maps the name of the section which can be represented as a C
	57	// identifier (cident) to the list of sections that have that name.
	58	// Different object files can have cident sections with the same name.
	59	typedef std::map<std::string, Sections_reachable> Cident_section_map;
6d03d481	60
ef15dade ST	61	Garbage_collection()
	62	: is_worklist_ready_(false)
	63	{ }
	64
	65	// Accessor methods for the private members.
	66
	67	Sections_reachable&
	68	referenced_list()
	69	{ return referenced_list_; }
	70
	71	Section_ref&
	72	section_reloc_map()
	73	{ return this->section_reloc_map_; }
	74
	75	Worklist_type&
	76	worklist()
	77	{ return this->work_list_; }
	78
	79	bool
	80	is_worklist_ready()
	81	{ return this->is_worklist_ready_; }
	82
	83	void
	84	worklist_ready()
	85	{ this->is_worklist_ready_ = true; }
	86
	87	void
	88	do_transitive_closure();
	89
	90	bool
	91	is_section_garbage(Object* obj, unsigned int shndx)
	92	{ return (this->referenced_list().find(Section_id(obj, shndx))
	93	== this->referenced_list().end()); }
f1ec9ded ST	94
	95	Cident_section_map*
	96	cident_sections()
	97	{ return &cident_sections_; }
	98
	99	void
	100	add_cident_section(std::string section_name,
	101	Section_id secn)
	102	{ this->cident_sections_[section_name].insert(secn); }
	103
99e5bff2 DK	104	// Add a reference from the SRC_SHNDX-th section of SRC_OBJECT to
	105	// DST_SHNDX-th section of DST_OBJECT.
	106	void
	107	add_reference(Object* src_object, unsigned int src_shndx,
	108	Object* dst_object, unsigned int dst_shndx)
	109	{
	110	Section_id src_id(src_object, src_shndx);
	111	Section_id dst_id(dst_object, dst_shndx);
	112	Section_ref::iterator p = this->section_reloc_map_.find(src_id);
	113	if (p == this->section_reloc_map_.end())
	114	this->section_reloc_map_[src_id].insert(dst_id);
	115	else
	116	p->second.insert(dst_id);
	117	}
	118
ef15dade ST	119	private:
	120
	121	Worklist_type work_list_;
	122	bool is_worklist_ready_;
	123	Section_ref section_reloc_map_;
	124	Sections_reachable referenced_list_;
f1ec9ded	125	Cident_section_map cident_sections_;
6d03d481 ST	126	};
	127
	128	// Data to pass between successive invocations of do_layout
	129	// in object.cc while garbage collecting. This data structure
	130	// is filled by using the data from Read_symbols_data.
	131
	132	struct Symbols_data
	133	{
	134	// Section headers.
	135	unsigned char* section_headers_data;
	136	// Section names.
	137	unsigned char* section_names_data;
	138	// Size of section name data in bytes.
	139	section_size_type section_names_size;
	140	// Symbol data.
	141	unsigned char* symbols_data;
	142	// Size of symbol data in bytes.
	143	section_size_type symbols_size;
	144	// Offset of external symbols within symbol data. This structure
	145	// sometimes contains only external symbols, in which case this will
	146	// be zero. Sometimes it contains all symbols.
	147	section_offset_type external_symbols_offset;
	148	// Symbol names.
	149	unsigned char* symbol_names_data;
	150	// Size of symbol name data in bytes.
	151	section_size_type symbol_names_size;
	152	};
	153
41cbeecc ST	154	// Relocations of type SHT_REL store the addend value in their bytes.
	155	// This function returns the size of the embedded addend which is
	156	// nothing but the size of the relocation.
	157
	158	template<typename Classify_reloc>
	159	inline unsigned int
	160	get_embedded_addend_size(int sh_type, int r_type, Relobj* obj)
	161	{
	162	if (sh_type != elfcpp::SHT_REL)
	163	return 0;
	164	Classify_reloc classify_reloc;
	165	return classify_reloc.get_size_for_reloc(r_type, obj);
	166	}
	167
ef15dade ST	168	// This function implements the generic part of reloc
	169	// processing to map a section to all the sections it
	170	// references through relocs. It is called only during
	171	// garbage collection (--gc-sections) and identical code
	172	// folding (--icf).
6d03d481 ST	173
6d03d481 ST	174	template<int size, bool big_endian, typename Target_type, int sh_type,
41cbeecc	175	typename Scan, typename Classify_reloc>
6d03d481 ST	176	inline void
6d03d481 ST	177	gc_process_relocs(
6d03d481 ST	178	Symbol_table* symtab,
6d03d481 ST	179	Layout*,
21bb3914	180	Target_type* target,
6fa2a40b	181	Sized_relobj_file<size, big_endian>* src_obj,
ef15dade	182	unsigned int src_indx,
6d03d481 ST	183	const unsigned char* prelocs,
	184	size_t reloc_count,
	185	Output_section*,
21bb3914	186	bool,
6d03d481 ST	187	size_t local_count,
	188	const unsigned char* plocal_syms)
	189	{
ca09d69a	190	Object* dst_obj;
ef15dade	191	unsigned int dst_indx;
21bb3914	192	Scan scan;
6d03d481	193
6d03d481 ST	194	typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype;
	195	const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size;
	196	const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
	197
b487ad64 ST	198	Icf::Sections_reachable_info* secvec = NULL;
	199	Icf::Symbol_info* symvec = NULL;
	200	Icf::Addend_info* addendvec = NULL;
	201	Icf::Offset_info* offsetvec = NULL;
41cbeecc	202	Icf::Reloc_addend_size_info* reloc_addend_size_vec = NULL;
ef15dade	203	bool is_icf_tracked = false;
f1ec9ded	204	const char* cident_section_name = NULL;
ef15dade	205
21bb3914 ST	206	std::string src_section_name = (parameters->options().icf_enabled()
	207	? src_obj->section_name(src_indx)
	208	: "");
	209
	210	bool check_section_for_function_pointers = false;
	211
032ce4e9	212	if (parameters->options().icf_enabled()
21bb3914	213	&& is_section_foldable_candidate(src_section_name.c_str()))
ef15dade ST	214	{
	215	is_icf_tracked = true;
	216	Section_id src_id(src_obj, src_indx);
b487ad64 ST	217	Icf::Reloc_info* reloc_info =
	218	&symtab->icf()->reloc_info_list()[src_id];
	219	secvec = &reloc_info->section_info;
	220	symvec = &reloc_info->symbol_info;
	221	addendvec = &reloc_info->addend_info;
	222	offsetvec = &reloc_info->offset_info;
41cbeecc	223	reloc_addend_size_vec = &reloc_info->reloc_addend_size_info;
ef15dade ST	224	}
ef15dade ST	225
21bb3914 ST	226	check_section_for_function_pointers =
	227	symtab->icf()->check_section_for_function_pointers(src_section_name,
	228	target);
	229
6d03d481 ST	230	for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size)
	231	{
	232	Reltype reloc(prelocs);
	233	typename elfcpp::Elf_types<size>::Elf_WXword r_info = reloc.get_r_info();
	234	unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
21bb3914	235	unsigned int r_type = elfcpp::elf_r_type<size>(r_info);
ef15dade ST	236	typename elfcpp::Elf_types<size>::Elf_Swxword addend =
	237	Reloc_types<sh_type, size, big_endian>::get_reloc_addend_noerror(&reloc);
	238
6d03d481 ST	239	if (r_sym < local_count)
	240	{
	241	gold_assert(plocal_syms != NULL);
	242	typename elfcpp::Sym<size, big_endian> lsym(plocal_syms
	243	+ r_sym * sym_size);
	244	unsigned int shndx = lsym.get_st_shndx();
	245	bool is_ordinary;
ef15dade	246	shndx = src_obj->adjust_sym_shndx(r_sym, shndx, &is_ordinary);
6d03d481	247	dst_obj = src_obj;
6d03d481	248	dst_indx = shndx;
ef15dade ST	249	if (is_icf_tracked)
ef15dade ST	250	{
ef38fd8a ST	251	if (is_ordinary)
	252	(*secvec).push_back(Section_id(dst_obj, dst_indx));
	253	else
	254	(*secvec).push_back(Section_id(NULL, 0));
ef15dade ST	255	(*symvec).push_back(NULL);
	256	long long symvalue = static_cast<long long>(lsym.get_st_value());
	257	(*addendvec).push_back(std::make_pair(symvalue,
	258	static_cast<long long>(addend)));
b487ad64 ST	259	uint64_t reloc_offset =
	260	convert_to_section_size_type(reloc.get_r_offset());
	261	(*offsetvec).push_back(reloc_offset);
41cbeecc ST	262	(*reloc_addend_size_vec).push_back(
	263	get_embedded_addend_size<Classify_reloc>(sh_type, r_type,
	264	src_obj));
ef15dade	265	}
21bb3914 ST	266
	267	// When doing safe folding, check to see if this relocation is that
	268	// of a function pointer being taken.
ef38fd8a ST	269	if (is_ordinary
ef38fd8a ST	270	&& check_section_for_function_pointers
21bb3914 ST	271	&& lsym.get_st_type() != elfcpp::STT_OBJECT
	272	&& scan.local_reloc_may_be_function_pointer(symtab, NULL, NULL,
	273	src_obj, src_indx,
	274	NULL, reloc, r_type,
	275	lsym))
	276	symtab->icf()->set_section_has_function_pointers(
	277	src_obj, lsym.get_st_shndx());
	278
ef38fd8a	279	if (!is_ordinary \|\| shndx == src_indx)
ef15dade	280	continue;
6d03d481 ST	281	}
	282	else
	283	{
ef15dade	284	Symbol* gsym = src_obj->global_symbol(r_sym);
6d03d481 ST	285	gold_assert(gsym != NULL);
	286	if (gsym->is_forwarder())
	287	gsym = symtab->resolve_forwards(gsym);
ef38fd8a ST	288
	289	dst_obj = NULL;
	290	dst_indx = 0;
	291	bool is_ordinary = false;
	292	if (gsym->source() == Symbol::FROM_OBJECT)
	293	{
	294	dst_obj = gsym->object();
	295	dst_indx = gsym->shndx(&is_ordinary);
	296	}
21bb3914 ST	297
	298	// When doing safe folding, check to see if this relocation is that
	299	// of a function pointer being taken.
ef38fd8a ST	300	if (gsym->source() == Symbol::FROM_OBJECT
ef38fd8a ST	301	&& check_section_for_function_pointers
21bb3914 ST	302	&& gsym->type() != elfcpp::STT_OBJECT
	303	&& (!is_ordinary
	304	\|\| scan.global_reloc_may_be_function_pointer(
	305	symtab, NULL, NULL, src_obj, src_indx, NULL, reloc,
	306	r_type, gsym)))
	307	symtab->icf()->set_section_has_function_pointers(dst_obj, dst_indx);
	308
f1ec9ded ST	309	// If the symbol name matches '__start_XXX' then the section with
	310	// the C identifier like name 'XXX' should not be garbage collected.
	311	// A similar treatment to symbols with the name '__stop_XXX'.
	312	if (is_prefix_of(cident_section_start_prefix, gsym->name()))
	313	{
	314	cident_section_name = (gsym->name()
	315	+ strlen(cident_section_start_prefix));
	316	}
	317	else if (is_prefix_of(cident_section_stop_prefix, gsym->name()))
	318	{
	319	cident_section_name = (gsym->name()
	320	+ strlen(cident_section_stop_prefix));
	321	}
ef15dade ST	322	if (is_icf_tracked)
ef15dade ST	323	{
ef38fd8a ST	324	if (is_ordinary && gsym->source() == Symbol::FROM_OBJECT)
	325	(*secvec).push_back(Section_id(dst_obj, dst_indx));
	326	else
	327	(*secvec).push_back(Section_id(NULL, 0));
ef15dade ST	328	(*symvec).push_back(gsym);
	329	Sized_symbol<size>* sized_gsym =
	330	static_cast<Sized_symbol<size>* >(gsym);
	331	long long symvalue =
	332	static_cast<long long>(sized_gsym->value());
	333	(*addendvec).push_back(std::make_pair(symvalue,
	334	static_cast<long long>(addend)));
b487ad64 ST	335	uint64_t reloc_offset =
	336	convert_to_section_size_type(reloc.get_r_offset());
	337	(*offsetvec).push_back(reloc_offset);
41cbeecc ST	338	(*reloc_addend_size_vec).push_back(
	339	get_embedded_addend_size<Classify_reloc>(sh_type, r_type,
	340	src_obj));
21bb3914	341	}
ef38fd8a ST	342
	343	if (gsym->source() != Symbol::FROM_OBJECT)
	344	continue;
	345	if (!is_ordinary)
	346	continue;
6d03d481	347	}
ef15dade	348	if (parameters->options().gc_sections())
6d03d481	349	{
99e5bff2	350	symtab->gc()->add_reference(src_obj, src_indx, dst_obj, dst_indx);
f1ec9ded ST	351	if (cident_section_name != NULL)
	352	{
	353	Garbage_collection::Cident_section_map::iterator ele =
	354	symtab->gc()->cident_sections()->find(std::string(cident_section_name));
	355	if (ele == symtab->gc()->cident_sections()->end())
	356	continue;
99e5bff2	357	Section_id src_id(src_obj, src_indx);
f1ec9ded ST	358	Garbage_collection::Sections_reachable&
	359	v(symtab->gc()->section_reloc_map()[src_id]);
	360	Garbage_collection::Sections_reachable& cident_secn(ele->second);
	361	for (Garbage_collection::Sections_reachable::iterator it_v
	362	= cident_secn.begin();
	363	it_v != cident_secn.end();
	364	++it_v)
	365	{
	366	v.insert(*it_v);
	367	}
	368	}
6d03d481 ST	369	}
	370	}
	371	return;
	372	}
	373
	374	} // End of namespace gold.
	375
	376	#endif