// gc.h -- garbage collection of unused sections
-// Copyright 2009, 2010 Free Software Foundation, Inc.
+// Copyright (C) 2009-2020 Free Software Foundation, Inc.
// Written by Sriraman Tallam <tmsriram@google.com>.
// This file is part of gold.
#ifndef GOLD_GC_H
#define GOLD_GC_H
-#include <queue>
#include <vector>
#include "elfcpp.h"
class Object;
template<int size, bool big_endian>
-class Sized_relobj;
-
-template<int sh_type, int size, bool big_endian>
-class Reloc_types;
+class Sized_relobj_file;
class Output_section;
class General_options;
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;
+ typedef std::vector<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.
do_transitive_closure();
bool
- is_section_garbage(Object* obj, unsigned int shndx)
+ is_section_garbage(Relobj* obj, unsigned int shndx)
{ return (this->referenced_list().find(Section_id(obj, shndx))
== this->referenced_list().end()); }
// 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)
+ add_reference(Relobj* src_object, unsigned int src_shndx,
+ Relobj* 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);
+ Sections_reachable& reachable = this->section_reloc_map_[src_id];
+ reachable.insert(dst_id);
}
private:
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 r_type, Relobj* obj)
+{
+ if (Classify_reloc::sh_type == elfcpp::SHT_REL)
+ return Classify_reloc::get_size_for_reloc(r_type, obj);
+ return 0;
+}
+
// 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>
+template<int size, bool big_endian, typename Target_type,
+ typename Scan, typename Classify_reloc>
inline void
gc_process_relocs(
Symbol_table* symtab,
Layout*,
Target_type* target,
- Sized_relobj<size, big_endian>* src_obj,
+ Sized_relobj_file<size, big_endian>* src_obj,
unsigned int src_indx,
const unsigned char* prelocs,
size_t reloc_count,
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;
+ typedef typename Classify_reloc::Reltype Reltype;
+ const int reloc_size = Classify_reloc::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;
bool check_section_for_function_pointers = false;
if (parameters->options().icf_enabled()
- && is_section_foldable_candidate(src_section_name.c_str()))
+ && (is_section_foldable_candidate(src_section_name)
+ || is_prefix_of(".eh_frame", src_section_name.c_str())))
{
is_icf_tracked = true;
Section_id src_id(src_obj, src_indx);
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 =
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);
+ unsigned int r_sym = Classify_reloc::get_r_sym(&reloc);
+ unsigned int r_type = Classify_reloc::get_r_type(&reloc);
typename elfcpp::Elf_types<size>::Elf_Swxword addend =
- Reloc_types<sh_type, size, big_endian>::get_reloc_addend_noerror(&reloc);
+ Classify_reloc::get_r_addend(&reloc);
+ Relobj* 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);
+ dst_indx = src_obj->adjust_sym_shndx(r_sym, dst_indx, &is_ordinary);
dst_obj = src_obj;
- dst_indx = shndx;
+ 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));
+ (*secvec).push_back(Section_id(src_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)));
+ // If the target of the relocation is an STT_SECTION symbol,
+ // make a note of that by storing -1 in the symbol vector.
+ if (lsym.get_st_type() == elfcpp::STT_SECTION)
+ (*symvec).push_back(reinterpret_cast<Symbol*>(-1));
+ else
+ (*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>(r_type, src_obj));
}
// When doing safe folding, check to see if this relocation is that
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,
+ && scan.local_reloc_may_be_function_pointer(symtab, NULL, target,
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)
+ if (!is_ordinary || dst_indx == src_indx)
continue;
}
else
dst_obj = NULL;
dst_indx = 0;
bool is_ordinary = false;
- if (gsym->source() == Symbol::FROM_OBJECT)
+ if (gsym->source() == Symbol::FROM_OBJECT
+ && !gsym->object()->is_dynamic())
{
- dst_obj = gsym->object();
+ dst_obj = static_cast<Relobj*>(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
+ && gsym->type() == elfcpp::STT_FUNC
&& check_section_for_function_pointers
- && gsym->type() != elfcpp::STT_OBJECT
+ && dst_obj != NULL
&& (!is_ordinary
|| scan.global_reloc_may_be_function_pointer(
- symtab, NULL, NULL, src_obj, src_indx, NULL, reloc,
+ symtab, NULL, target, src_obj, src_indx, NULL, reloc,
r_type, gsym)))
symtab->icf()->set_section_has_function_pointers(dst_obj, dst_indx);
}
if (is_icf_tracked)
{
- if (is_ordinary && gsym->source() == Symbol::FROM_OBJECT)
- (*secvec).push_back(Section_id(dst_obj, dst_indx));
+ Address symvalue = dst_off - addend;
+ if (is_ordinary && dst_obj != NULL)
+ (*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>(r_type, src_obj));
}
- if (gsym->source() != Symbol::FROM_OBJECT)
+ if (dst_obj == NULL)
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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