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

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

// Copyright (C) 2009-2015 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);
    Sections_reachable& reachable = this->section_reloc_map_[src_id];
    reachable.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)
{
  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);
      Object* dst_obj;
      unsigned int dst_indx;
      typedef typename elfcpp::Elf_types<size>::Elf_Addr Address;
      Address dst_off;

      if (r_sym < local_count)
        {
          gold_assert(plocal_syms != NULL);
          typename elfcpp::Sym<size, big_endian> lsym(plocal_syms
                                                      + r_sym * sym_size);
	  dst_indx = lsym.get_st_shndx();
          bool is_ordinary;
	  dst_indx = src_obj->adjust_sym_shndx(r_sym, dst_indx, &is_ordinary);
          dst_obj = src_obj;
	  dst_off = lsym.get_st_value() + addend;

          if (is_icf_tracked)
            {
	      Address symvalue = dst_off - addend;
	      if (is_ordinary) 
		(*secvec).push_back(Section_id(dst_obj, dst_indx));
	      else
                (*secvec).push_back(Section_id(NULL, 0));
              (*symvec).push_back(NULL);
	      (*addendvec).push_back(std::make_pair(
					static_cast<long long>(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 || dst_indx == 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);
            }
	  dst_off = static_cast<const Sized_symbol<size>*>(gsym)->value();
	  dst_off += addend;

	  // 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)
            {
	      Address symvalue = dst_off - addend;
              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);
	      (*addendvec).push_back(std::make_pair(
					static_cast<long long>(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);
	  parameters->sized_target<size, big_endian>()
	    ->gc_add_reference(symtab, src_obj, src_indx,
			       dst_obj, dst_indx, dst_off);
          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
b90efa5b	3	// Copyright (C) 2009-2015 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);
3a935c6c RÁE	112	Sections_reachable& reachable = this->section_reloc_map_[src_id];
3a935c6c RÁE	113	reachable.insert(dst_id);
99e5bff2 DK	114	}
99e5bff2 DK	115
ef15dade ST	116	private:
	117
	118	Worklist_type work_list_;
	119	bool is_worklist_ready_;
	120	Section_ref section_reloc_map_;
	121	Sections_reachable referenced_list_;
f1ec9ded	122	Cident_section_map cident_sections_;
6d03d481 ST	123	};
	124
	125	// Data to pass between successive invocations of do_layout
	126	// in object.cc while garbage collecting. This data structure
	127	// is filled by using the data from Read_symbols_data.
	128
	129	struct Symbols_data
	130	{
	131	// Section headers.
	132	unsigned char* section_headers_data;
	133	// Section names.
	134	unsigned char* section_names_data;
	135	// Size of section name data in bytes.
	136	section_size_type section_names_size;
	137	// Symbol data.
	138	unsigned char* symbols_data;
	139	// Size of symbol data in bytes.
	140	section_size_type symbols_size;
	141	// Offset of external symbols within symbol data. This structure
	142	// sometimes contains only external symbols, in which case this will
	143	// be zero. Sometimes it contains all symbols.
	144	section_offset_type external_symbols_offset;
	145	// Symbol names.
	146	unsigned char* symbol_names_data;
	147	// Size of symbol name data in bytes.
	148	section_size_type symbol_names_size;
	149	};
	150
41cbeecc ST	151	// Relocations of type SHT_REL store the addend value in their bytes.
	152	// This function returns the size of the embedded addend which is
	153	// nothing but the size of the relocation.
	154
	155	template<typename Classify_reloc>
	156	inline unsigned int
	157	get_embedded_addend_size(int sh_type, int r_type, Relobj* obj)
	158	{
	159	if (sh_type != elfcpp::SHT_REL)
	160	return 0;
	161	Classify_reloc classify_reloc;
	162	return classify_reloc.get_size_for_reloc(r_type, obj);
	163	}
	164
ef15dade ST	165	// This function implements the generic part of reloc
	166	// processing to map a section to all the sections it
	167	// references through relocs. It is called only during
	168	// garbage collection (--gc-sections) and identical code
	169	// folding (--icf).
6d03d481 ST	170
6d03d481 ST	171	template<int size, bool big_endian, typename Target_type, int sh_type,
41cbeecc	172	typename Scan, typename Classify_reloc>
6d03d481 ST	173	inline void
6d03d481 ST	174	gc_process_relocs(
6d03d481 ST	175	Symbol_table* symtab,
6d03d481 ST	176	Layout*,
21bb3914	177	Target_type* target,
6fa2a40b	178	Sized_relobj_file<size, big_endian>* src_obj,
ef15dade	179	unsigned int src_indx,
6d03d481 ST	180	const unsigned char* prelocs,
	181	size_t reloc_count,
	182	Output_section*,
21bb3914	183	bool,
6d03d481 ST	184	size_t local_count,
	185	const unsigned char* plocal_syms)
	186	{
21bb3914	187	Scan scan;
6d03d481	188
6d03d481 ST	189	typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype;
	190	const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size;
	191	const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
	192
b487ad64 ST	193	Icf::Sections_reachable_info* secvec = NULL;
	194	Icf::Symbol_info* symvec = NULL;
	195	Icf::Addend_info* addendvec = NULL;
	196	Icf::Offset_info* offsetvec = NULL;
41cbeecc	197	Icf::Reloc_addend_size_info* reloc_addend_size_vec = NULL;
ef15dade	198	bool is_icf_tracked = false;
f1ec9ded	199	const char* cident_section_name = NULL;
ef15dade	200
21bb3914 ST	201	std::string src_section_name = (parameters->options().icf_enabled()
	202	? src_obj->section_name(src_indx)
	203	: "");
	204
	205	bool check_section_for_function_pointers = false;
	206
032ce4e9	207	if (parameters->options().icf_enabled()
21bb3914	208	&& is_section_foldable_candidate(src_section_name.c_str()))
ef15dade ST	209	{
	210	is_icf_tracked = true;
	211	Section_id src_id(src_obj, src_indx);
b487ad64 ST	212	Icf::Reloc_info* reloc_info =
	213	&symtab->icf()->reloc_info_list()[src_id];
	214	secvec = &reloc_info->section_info;
	215	symvec = &reloc_info->symbol_info;
	216	addendvec = &reloc_info->addend_info;
	217	offsetvec = &reloc_info->offset_info;
41cbeecc	218	reloc_addend_size_vec = &reloc_info->reloc_addend_size_info;
ef15dade ST	219	}
ef15dade ST	220
21bb3914 ST	221	check_section_for_function_pointers =
	222	symtab->icf()->check_section_for_function_pointers(src_section_name,
	223	target);
	224
6d03d481 ST	225	for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size)
	226	{
	227	Reltype reloc(prelocs);
	228	typename elfcpp::Elf_types<size>::Elf_WXword r_info = reloc.get_r_info();
	229	unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
21bb3914	230	unsigned int r_type = elfcpp::elf_r_type<size>(r_info);
ef15dade ST	231	typename elfcpp::Elf_types<size>::Elf_Swxword addend =
ef15dade ST	232	Reloc_types<sh_type, size, big_endian>::get_reloc_addend_noerror(&reloc);
e81fea4d AM	233	Object* dst_obj;
e81fea4d AM	234	unsigned int dst_indx;
57420c20 AM	235	typedef typename elfcpp::Elf_types<size>::Elf_Addr Address;
57420c20 AM	236	Address dst_off;
ef15dade	237
6d03d481 ST	238	if (r_sym < local_count)
	239	{
	240	gold_assert(plocal_syms != NULL);
	241	typename elfcpp::Sym<size, big_endian> lsym(plocal_syms
	242	+ r_sym * sym_size);
57420c20	243	dst_indx = lsym.get_st_shndx();
6d03d481	244	bool is_ordinary;
57420c20	245	dst_indx = src_obj->adjust_sym_shndx(r_sym, dst_indx, &is_ordinary);
6d03d481	246	dst_obj = src_obj;
57420c20	247	dst_off = lsym.get_st_value() + addend;
e81fea4d	248
ef15dade ST	249	if (is_icf_tracked)
ef15dade ST	250	{
57420c20	251	Address symvalue = dst_off - addend;
ef38fd8a	252	if (is_ordinary)
ad3d8a2f	253	(*secvec).push_back(Section_id(dst_obj, dst_indx));
ef38fd8a ST	254	else
ef38fd8a ST	255	(*secvec).push_back(Section_id(NULL, 0));
ef15dade	256	(*symvec).push_back(NULL);
57420c20 AM	257	(*addendvec).push_back(std::make_pair(
	258	static_cast<long long>(symvalue),
	259	static_cast<long long>(addend)));
b487ad64 ST	260	uint64_t reloc_offset =
	261	convert_to_section_size_type(reloc.get_r_offset());
	262	(*offsetvec).push_back(reloc_offset);
41cbeecc ST	263	(*reloc_addend_size_vec).push_back(
	264	get_embedded_addend_size<Classify_reloc>(sh_type, r_type,
	265	src_obj));
ef15dade	266	}
21bb3914 ST	267
	268	// When doing safe folding, check to see if this relocation is that
	269	// of a function pointer being taken.
ef38fd8a ST	270	if (is_ordinary
ef38fd8a ST	271	&& check_section_for_function_pointers
21bb3914 ST	272	&& lsym.get_st_type() != elfcpp::STT_OBJECT
	273	&& scan.local_reloc_may_be_function_pointer(symtab, NULL, NULL,
	274	src_obj, src_indx,
	275	NULL, reloc, r_type,
	276	lsym))
	277	symtab->icf()->set_section_has_function_pointers(
	278	src_obj, lsym.get_st_shndx());
	279
57420c20	280	if (!is_ordinary \|\| dst_indx == src_indx)
ef15dade	281	continue;
6d03d481 ST	282	}
	283	else
	284	{
ef15dade	285	Symbol* gsym = src_obj->global_symbol(r_sym);
6d03d481 ST	286	gold_assert(gsym != NULL);
	287	if (gsym->is_forwarder())
	288	gsym = symtab->resolve_forwards(gsym);
ef38fd8a ST	289
	290	dst_obj = NULL;
	291	dst_indx = 0;
	292	bool is_ordinary = false;
	293	if (gsym->source() == Symbol::FROM_OBJECT)
	294	{
	295	dst_obj = gsym->object();
	296	dst_indx = gsym->shndx(&is_ordinary);
	297	}
57420c20 AM	298	dst_off = static_cast<const Sized_symbol<size>*>(gsym)->value();
57420c20 AM	299	dst_off += addend;
21bb3914 ST	300
	301	// When doing safe folding, check to see if this relocation is that
	302	// of a function pointer being taken.
ef38fd8a ST	303	if (gsym->source() == Symbol::FROM_OBJECT
ef38fd8a ST	304	&& check_section_for_function_pointers
21bb3914 ST	305	&& gsym->type() != elfcpp::STT_OBJECT
	306	&& (!is_ordinary
	307	\|\| scan.global_reloc_may_be_function_pointer(
	308	symtab, NULL, NULL, src_obj, src_indx, NULL, reloc,
	309	r_type, gsym)))
	310	symtab->icf()->set_section_has_function_pointers(dst_obj, dst_indx);
	311
f1ec9ded ST	312	// If the symbol name matches '__start_XXX' then the section with
	313	// the C identifier like name 'XXX' should not be garbage collected.
	314	// A similar treatment to symbols with the name '__stop_XXX'.
	315	if (is_prefix_of(cident_section_start_prefix, gsym->name()))
	316	{
	317	cident_section_name = (gsym->name()
	318	+ strlen(cident_section_start_prefix));
	319	}
	320	else if (is_prefix_of(cident_section_stop_prefix, gsym->name()))
	321	{
	322	cident_section_name = (gsym->name()
	323	+ strlen(cident_section_stop_prefix));
	324	}
ef15dade ST	325	if (is_icf_tracked)
ef15dade ST	326	{
57420c20	327	Address symvalue = dst_off - addend;
ef38fd8a	328	if (is_ordinary && gsym->source() == Symbol::FROM_OBJECT)
ad3d8a2f	329	(*secvec).push_back(Section_id(dst_obj, dst_indx));
ef38fd8a ST	330	else
ef38fd8a ST	331	(*secvec).push_back(Section_id(NULL, 0));
ef15dade	332	(*symvec).push_back(gsym);
57420c20 AM	333	(*addendvec).push_back(std::make_pair(
	334	static_cast<long long>(symvalue),
	335	static_cast<long long>(addend)));
b487ad64 ST	336	uint64_t reloc_offset =
	337	convert_to_section_size_type(reloc.get_r_offset());
	338	(*offsetvec).push_back(reloc_offset);
41cbeecc ST	339	(*reloc_addend_size_vec).push_back(
	340	get_embedded_addend_size<Classify_reloc>(sh_type, r_type,
	341	src_obj));
21bb3914	342	}
ef38fd8a ST	343
	344	if (gsym->source() != Symbol::FROM_OBJECT)
	345	continue;
	346	if (!is_ordinary)
	347	continue;
6d03d481	348	}
ef15dade	349	if (parameters->options().gc_sections())
6d03d481	350	{
99e5bff2	351	symtab->gc()->add_reference(src_obj, src_indx, dst_obj, dst_indx);
e81fea4d AM	352	parameters->sized_target<size, big_endian>()
	353	->gc_add_reference(symtab, src_obj, src_indx,
	354	dst_obj, dst_indx, dst_off);
f1ec9ded ST	355	if (cident_section_name != NULL)
	356	{
	357	Garbage_collection::Cident_section_map::iterator ele =
	358	symtab->gc()->cident_sections()->find(std::string(cident_section_name));
	359	if (ele == symtab->gc()->cident_sections()->end())
	360	continue;
99e5bff2	361	Section_id src_id(src_obj, src_indx);
f1ec9ded ST	362	Garbage_collection::Sections_reachable&
	363	v(symtab->gc()->section_reloc_map()[src_id]);
	364	Garbage_collection::Sections_reachable& cident_secn(ele->second);
	365	for (Garbage_collection::Sections_reachable::iterator it_v
	366	= cident_secn.begin();
	367	it_v != cident_secn.end();
	368	++it_v)
	369	{
	370	v.insert(*it_v);
	371	}
	372	}
6d03d481 ST	373	}
	374	}
	375	return;
	376	}
	377
	378	} // End of namespace gold.
	379
	380	#endif