// gc.h -- garbage collection of unused sections
-// Copyright 2009, 2010 Free Software Foundation, Inc.
+// Copyright (C) 2009-2014 Free Software Foundation, Inc.
// Written by Sriraman Tallam <tmsriram@google.com>.
// This file is part of gold.
#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;
+class Sized_relobj_file;
template<int sh_type, int size, bool big_endian>
-class Reloc_types;
+struct Reloc_types;
class Output_section;
class General_options;
class Layout;
-typedef std::pair<Object *, unsigned int> Section_id;
-
class Garbage_collection
{
- struct Section_id_hash
- {
- size_t operator()(const Section_id& loc) const
- { return reinterpret_cast<uintptr_t>(loc.first) ^ loc.second; }
- };
-
public:
typedef Unordered_set<Section_id, Section_id_hash> Sections_reachable;
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
// folding (--icf).
template<int size, bool big_endian, typename Target_type, int sh_type,
- typename Scan>
+ typename Scan, typename Classify_reloc>
inline void
gc_process_relocs(
Symbol_table* symtab,
Layout*,
- Target_type* ,
- Sized_relobj<size, big_endian>* src_obj,
+ 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 ,
+ 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;
- std::vector<Section_id>* secvec = NULL;
- std::vector<Symbol*>* symvec = NULL;
- std::vector<std::pair<long long, long long> >* addendvec = NULL;
+ 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_obj->section_name(src_indx).c_str()))
+ && is_section_foldable_candidate(src_section_name.c_str()))
{
is_icf_tracked = true;
Section_id src_id(src_obj, src_indx);
- secvec = &symtab->icf()->section_reloc_list()[src_id];
- symvec = &symtab->icf()->symbol_reloc_list()[src_id];
- addendvec = &symtab->icf()->addend_reloc_list()[src_id];
+ 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);
- unsigned int shndx = lsym.get_st_shndx();
+ dst_indx = lsym.get_st_shndx();
bool is_ordinary;
- shndx = src_obj->adjust_sym_shndx(r_sym, shndx, &is_ordinary);
- if (!is_ordinary)
- continue;
+ dst_indx = src_obj->adjust_sym_shndx(r_sym, dst_indx, &is_ordinary);
dst_obj = src_obj;
- dst_indx = shndx;
- Section_id dst_id(dst_obj, dst_indx);
+ dst_off = lsym.get_st_value() + addend;
+
if (is_icf_tracked)
{
- (*secvec).push_back(dst_id);
+ 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);
- long long symvalue = static_cast<long long>(lsym.get_st_value());
- (*addendvec).push_back(std::make_pair(symvalue,
- static_cast<long long>(addend)));
+ (*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 (shndx == src_indx)
+
+ // 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
gold_assert(gsym != NULL);
if (gsym->is_forwarder())
gsym = symtab->resolve_forwards(gsym);
- if (gsym->source() != Symbol::FROM_OBJECT)
- continue;
- bool is_ordinary;
- dst_obj = gsym->object();
- dst_indx = gsym->shndx(&is_ordinary);
- if (!is_ordinary)
- continue;
- Section_id dst_id(dst_obj, dst_indx);
+
+ 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_icf_tracked)
{
- (*secvec).push_back(dst_id);
+ 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);
- 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)));
- }
+ (*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 =
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