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binutils-gdb/gold/symtab.cc

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// symtab.cc -- the gold symbol table
// Copyright (C) 2006-2019 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 <cstring>
#include <stdint.h>
#include <algorithm>
#include <set>
#include <string>
#include <utility>
#include "demangle.h"
#include "gc.h"
#include "object.h"
#include "dwarf_reader.h"
#include "dynobj.h"
#include "output.h"
#include "target.h"
#include "workqueue.h"
#include "symtab.h"
#include "script.h"
#include "plugin.h"
#include "incremental.h"
namespace gold
{
// Class Symbol.
// Initialize fields in Symbol. This initializes everything except
// u1_, u2_ and source_.
void
Symbol::init_fields(const char* name, const char* version,
elfcpp::STT type, elfcpp::STB binding,
elfcpp::STV visibility, unsigned char nonvis)
{
this->name_ = name;
this->version_ = version;
this->symtab_index_ = 0;
this->dynsym_index_ = 0;
this->got_offsets_.init();
this->plt_offset_ = -1U;
this->type_ = type;
this->binding_ = binding;
this->visibility_ = visibility;
this->nonvis_ = nonvis;
this->is_def_ = false;
this->is_forwarder_ = false;
this->has_alias_ = false;
this->needs_dynsym_entry_ = false;
this->in_reg_ = false;
this->in_dyn_ = false;
this->has_warning_ = false;
this->is_copied_from_dynobj_ = false;
this->is_forced_local_ = false;
this->is_ordinary_shndx_ = false;
this->in_real_elf_ = false;
this->is_defined_in_discarded_section_ = false;
this->undef_binding_set_ = false;
this->undef_binding_weak_ = false;
this->is_predefined_ = false;
this->is_protected_ = false;
this->non_zero_localentry_ = false;
}
// Return the demangled version of the symbol's name, but only
// if the --demangle flag was set.
static std::string
demangle(const char* name)
{
if (!parameters->options().do_demangle())
return name;
// cplus_demangle allocates memory for the result it returns,
// and returns NULL if the name is already demangled.
char* demangled_name = cplus_demangle(name, DMGL_ANSI | DMGL_PARAMS);
if (demangled_name == NULL)
return name;
std::string retval(demangled_name);
free(demangled_name);
return retval;
}
std::string
Symbol::demangled_name() const
{
return demangle(this->name());
}
// Initialize the fields in the base class Symbol for SYM in OBJECT.
template<int size, bool big_endian>
void
Symbol::init_base_object(const char* name, const char* version, Object* object,
const elfcpp::Sym<size, big_endian>& sym,
unsigned int st_shndx, bool is_ordinary)
{
this->init_fields(name, version, sym.get_st_type(), sym.get_st_bind(),
sym.get_st_visibility(), sym.get_st_nonvis());
this->u1_.object = object;
this->u2_.shndx = st_shndx;
this->is_ordinary_shndx_ = is_ordinary;
this->source_ = FROM_OBJECT;
this->in_reg_ = !object->is_dynamic();
this->in_dyn_ = object->is_dynamic();
this->in_real_elf_ = object->pluginobj() == NULL;
}
// Initialize the fields in the base class Symbol for a symbol defined
// in an Output_data.
void
Symbol::init_base_output_data(const char* name, const char* version,
Output_data* od, elfcpp::STT type,
elfcpp::STB binding, elfcpp::STV visibility,
unsigned char nonvis, bool offset_is_from_end,
bool is_predefined)
{
this->init_fields(name, version, type, binding, visibility, nonvis);
this->u1_.output_data = od;
this->u2_.offset_is_from_end = offset_is_from_end;
this->source_ = IN_OUTPUT_DATA;
this->in_reg_ = true;
this->in_real_elf_ = true;
this->is_predefined_ = is_predefined;
}
// Initialize the fields in the base class Symbol for a symbol defined
// in an Output_segment.
void
Symbol::init_base_output_segment(const char* name, const char* version,
Output_segment* os, elfcpp::STT type,
elfcpp::STB binding, elfcpp::STV visibility,
unsigned char nonvis,
Segment_offset_base offset_base,
bool is_predefined)
{
this->init_fields(name, version, type, binding, visibility, nonvis);
this->u1_.output_segment = os;
this->u2_.offset_base = offset_base;
this->source_ = IN_OUTPUT_SEGMENT;
this->in_reg_ = true;
this->in_real_elf_ = true;
this->is_predefined_ = is_predefined;
}
// Initialize the fields in the base class Symbol for a symbol defined
// as a constant.
void
Symbol::init_base_constant(const char* name, const char* version,
elfcpp::STT type, elfcpp::STB binding,
elfcpp::STV visibility, unsigned char nonvis,
bool is_predefined)
{
this->init_fields(name, version, type, binding, visibility, nonvis);
this->source_ = IS_CONSTANT;
this->in_reg_ = true;
this->in_real_elf_ = true;
this->is_predefined_ = is_predefined;
}
// Initialize the fields in the base class Symbol for an undefined
// symbol.
void
Symbol::init_base_undefined(const char* name, const char* version,
elfcpp::STT type, elfcpp::STB binding,
elfcpp::STV visibility, unsigned char nonvis)
{
this->init_fields(name, version, type, binding, visibility, nonvis);
this->dynsym_index_ = -1U;
this->source_ = IS_UNDEFINED;
this->in_reg_ = true;
this->in_real_elf_ = true;
}
// Allocate a common symbol in the base.
void
Symbol::allocate_base_common(Output_data* od)
{
gold_assert(this->is_common());
this->source_ = IN_OUTPUT_DATA;
this->u1_.output_data = od;
this->u2_.offset_is_from_end = false;
}
// Initialize the fields in Sized_symbol for SYM in OBJECT.
template<int size>
template<bool big_endian>
void
Sized_symbol<size>::init_object(const char* name, const char* version,
Object* object,
const elfcpp::Sym<size, big_endian>& sym,
unsigned int st_shndx, bool is_ordinary)
{
this->init_base_object(name, version, object, sym, st_shndx, is_ordinary);
this->value_ = sym.get_st_value();
this->symsize_ = sym.get_st_size();
}
// Initialize the fields in Sized_symbol for a symbol defined in an
// Output_data.
template<int size>
void
Sized_symbol<size>::init_output_data(const char* name, const char* version,
Output_data* od, Value_type value,
Size_type symsize, elfcpp::STT type,
elfcpp::STB binding,
elfcpp::STV visibility,
unsigned char nonvis,
bool offset_is_from_end,
bool is_predefined)
{
this->init_base_output_data(name, version, od, type, binding, visibility,
nonvis, offset_is_from_end, is_predefined);
this->value_ = value;
this->symsize_ = symsize;
}
// Initialize the fields in Sized_symbol for a symbol defined in an
// Output_segment.
template<int size>
void
Sized_symbol<size>::init_output_segment(const char* name, const char* version,
Output_segment* os, Value_type value,
Size_type symsize, elfcpp::STT type,
elfcpp::STB binding,
elfcpp::STV visibility,
unsigned char nonvis,
Segment_offset_base offset_base,
bool is_predefined)
{
this->init_base_output_segment(name, version, os, type, binding, visibility,
nonvis, offset_base, is_predefined);
this->value_ = value;
this->symsize_ = symsize;
}
// Initialize the fields in Sized_symbol for a symbol defined as a
// constant.
template<int size>
void
Sized_symbol<size>::init_constant(const char* name, const char* version,
Value_type value, Size_type symsize,
elfcpp::STT type, elfcpp::STB binding,
elfcpp::STV visibility, unsigned char nonvis,
bool is_predefined)
{
this->init_base_constant(name, version, type, binding, visibility, nonvis,
is_predefined);
this->value_ = value;
this->symsize_ = symsize;
}
// Initialize the fields in Sized_symbol for an undefined symbol.
template<int size>
void
Sized_symbol<size>::init_undefined(const char* name, const char* version,
Value_type value, elfcpp::STT type,
elfcpp::STB binding, elfcpp::STV visibility,
unsigned char nonvis)
{
this->init_base_undefined(name, version, type, binding, visibility, nonvis);
this->value_ = value;
this->symsize_ = 0;
}
// Return an allocated string holding the symbol's name as
// name@version. This is used for relocatable links.
std::string
Symbol::versioned_name() const
{
gold_assert(this->version_ != NULL);
std::string ret = this->name_;
ret.push_back('@');
if (this->is_def_)
ret.push_back('@');
ret += this->version_;
return ret;
}
// Return true if SHNDX represents a common symbol.
bool
Symbol::is_common_shndx(unsigned int shndx)
{
return (shndx == elfcpp::SHN_COMMON
|| shndx == parameters->target().small_common_shndx()
|| shndx == parameters->target().large_common_shndx());
}
// Allocate a common symbol.
template<int size>
void
Sized_symbol<size>::allocate_common(Output_data* od, Value_type value)
{
this->allocate_base_common(od);
this->value_ = value;
}
// The ""'s around str ensure str is a string literal, so sizeof works.
#define strprefix(var, str) (strncmp(var, str, sizeof("" str "") - 1) == 0)
// Return true if this symbol should be added to the dynamic symbol
// table.
bool
Symbol::should_add_dynsym_entry(Symbol_table* symtab) const
{
// If the symbol is only present on plugin files, the plugin decided we
// don't need it.
if (!this->in_real_elf())
return false;
// If the symbol is used by a dynamic relocation, we need to add it.
if (this->needs_dynsym_entry())
return true;
// If this symbol's section is not added, the symbol need not be added.
// The section may have been GCed. Note that export_dynamic is being
// overridden here. This should not be done for shared objects.
if (parameters->options().gc_sections()
&& !parameters->options().shared()
&& this->source() == Symbol::FROM_OBJECT
&& !this->object()->is_dynamic())
{
Relobj* relobj = static_cast<Relobj*>(this->object());
bool is_ordinary;
unsigned int shndx = this->shndx(&is_ordinary);
if (is_ordinary && shndx != elfcpp::SHN_UNDEF
&& !relobj->is_section_included(shndx)
&& !symtab->is_section_folded(relobj, shndx))
return false;
}
// If the symbol was forced dynamic in a --dynamic-list file
// or an --export-dynamic-symbol option, add it.
if (!this->is_from_dynobj()
&& (parameters->options().in_dynamic_list(this->name())
|| parameters->options().is_export_dynamic_symbol(this->name())))
{
if (!this->is_forced_local())
return true;
gold_warning(_("Cannot export local symbol '%s'"),
this->demangled_name().c_str());
return false;
}
// If the symbol was forced local in a version script, do not add it.
if (this->is_forced_local())
return false;
// If dynamic-list-data was specified, add any STT_OBJECT.
if (parameters->options().dynamic_list_data()
&& !this->is_from_dynobj()
&& this->type() == elfcpp::STT_OBJECT)
return true;
// If --dynamic-list-cpp-new was specified, add any new/delete symbol.
// If --dynamic-list-cpp-typeinfo was specified, add any typeinfo symbols.
if ((parameters->options().dynamic_list_cpp_new()
|| parameters->options().dynamic_list_cpp_typeinfo())
&& !this->is_from_dynobj())
{
// TODO(csilvers): We could probably figure out if we're an operator
// new/delete or typeinfo without the need to demangle.
char* demangled_name = cplus_demangle(this->name(),
DMGL_ANSI | DMGL_PARAMS);
if (demangled_name == NULL)
{
// Not a C++ symbol, so it can't satisfy these flags
}
else if (parameters->options().dynamic_list_cpp_new()
&& (strprefix(demangled_name, "operator new")
|| strprefix(demangled_name, "operator delete")))
{
free(demangled_name);
return true;
}
else if (parameters->options().dynamic_list_cpp_typeinfo()
&& (strprefix(demangled_name, "typeinfo name for")
|| strprefix(demangled_name, "typeinfo for")))
{
free(demangled_name);
return true;
}
else
free(demangled_name);
}
// If exporting all symbols or building a shared library,
// or the symbol should be globally unique (GNU_UNIQUE),
// and the symbol is defined in a regular object and is
// externally visible, we need to add it.
if ((parameters->options().export_dynamic()
|| parameters->options().shared()
|| (parameters->options().gnu_unique()
&& this->binding() == elfcpp::STB_GNU_UNIQUE))
&& !this->is_from_dynobj()
&& !this->is_undefined()
&& this->is_externally_visible())
return true;
return false;
}
// Return true if the final value of this symbol is known at link
// time.
bool
Symbol::final_value_is_known() const
{
// If we are not generating an executable, then no final values are
// known, since they will change at runtime, with the exception of
// TLS symbols in a position-independent executable.
if ((parameters->options().output_is_position_independent()
|| parameters->options().relocatable())
&& !(this->type() == elfcpp::STT_TLS
&& parameters->options().pie()))
return false;
// If the symbol is not from an object file, and is not undefined,
// then it is defined, and known.
if (this->source_ != FROM_OBJECT)
{
if (this->source_ != IS_UNDEFINED)
return true;
}
else
{
// If the symbol is from a dynamic object, then the final value
// is not known.
if (this->object()->is_dynamic())
return false;
// If the symbol is not undefined (it is defined or common),
// then the final value is known.
if (!this->is_undefined())
return true;
}
// If the symbol is undefined, then whether the final value is known
// depends on whether we are doing a static link. If we are doing a
// dynamic link, then the final value could be filled in at runtime.
// This could reasonably be the case for a weak undefined symbol.
return parameters->doing_static_link();
}
// Return the output section where this symbol is defined.
Output_section*
Symbol::output_section() const
{
switch (this->source_)
{
case FROM_OBJECT:
{
unsigned int shndx = this->u2_.shndx;
if (shndx != elfcpp::SHN_UNDEF && this->is_ordinary_shndx_)
{
gold_assert(!this->u1_.object->is_dynamic());
gold_assert(this->u1_.object->pluginobj() == NULL);
Relobj* relobj = static_cast<Relobj*>(this->u1_.object);
return relobj->output_section(shndx);
}
return NULL;
}
case IN_OUTPUT_DATA:
return this->u1_.output_data->output_section();
case IN_OUTPUT_SEGMENT:
case IS_CONSTANT:
case IS_UNDEFINED:
return NULL;
default:
gold_unreachable();
}
}
// Set the symbol's output section. This is used for symbols defined
// in scripts. This should only be called after the symbol table has
// been finalized.
void
Symbol::set_output_section(Output_section* os)
{
switch (this->source_)
{
case FROM_OBJECT:
case IN_OUTPUT_DATA:
gold_assert(this->output_section() == os);
break;
case IS_CONSTANT:
this->source_ = IN_OUTPUT_DATA;
this->u1_.output_data = os;
this->u2_.offset_is_from_end = false;
break;
case IN_OUTPUT_SEGMENT:
case IS_UNDEFINED:
default:
gold_unreachable();
}
}
// Set the symbol's output segment. This is used for pre-defined
// symbols whose segments aren't known until after layout is done
// (e.g., __ehdr_start).
void
Symbol::set_output_segment(Output_segment* os, Segment_offset_base base)
{
gold_assert(this->is_predefined_);
this->source_ = IN_OUTPUT_SEGMENT;
this->u1_.output_segment = os;
this->u2_.offset_base = base;
}
// Set the symbol to undefined. This is used for pre-defined
// symbols whose segments aren't known until after layout is done
// (e.g., __ehdr_start).
void
Symbol::set_undefined()
{
this->source_ = IS_UNDEFINED;
this->is_predefined_ = false;
}
// Class Symbol_table.
Symbol_table::Symbol_table(unsigned int count,
const Version_script_info& version_script)
: saw_undefined_(0), offset_(0), table_(count), namepool_(),
forwarders_(), commons_(), tls_commons_(), small_commons_(),
large_commons_(), forced_locals_(), warnings_(),
version_script_(version_script), gc_(NULL), icf_(NULL),
target_symbols_()
{
namepool_.reserve(count);
}
Symbol_table::~Symbol_table()
{
}
// The symbol table key equality function. This is called with
// Stringpool keys.
inline bool
Symbol_table::Symbol_table_eq::operator()(const Symbol_table_key& k1,
const Symbol_table_key& k2) const
{
return k1.first == k2.first && k1.second == k2.second;
}
bool
Symbol_table::is_section_folded(Relobj* obj, unsigned int shndx) const
{
return (parameters->options().icf_enabled()
&& this->icf_->is_section_folded(obj, shndx));
}
// For symbols that have been listed with a -u or --export-dynamic-symbol
// option, add them to the work list to avoid gc'ing them.
void
Symbol_table::gc_mark_undef_symbols(Layout* layout)
{
for (options::String_set::const_iterator p =
parameters->options().undefined_begin();
p != parameters->options().undefined_end();
++p)
{
const char* name = p->c_str();
Symbol* sym = this->lookup(name);
gold_assert(sym != NULL);
if (sym->source() == Symbol::FROM_OBJECT
&& !sym->object()->is_dynamic())
{
this->gc_mark_symbol(sym);
}
}
for (options::String_set::const_iterator p =
parameters->options().export_dynamic_symbol_begin();
p != parameters->options().export_dynamic_symbol_end();
++p)
{
const char* name = p->c_str();
Symbol* sym = this->lookup(name);
// It's not an error if a symbol named by --export-dynamic-symbol
// is undefined.
if (sym != NULL
&& sym->source() == Symbol::FROM_OBJECT
&& !sym->object()->is_dynamic())
{
this->gc_mark_symbol(sym);
}
}
for (Script_options::referenced_const_iterator p =
layout->script_options()->referenced_begin();
p != layout->script_options()->referenced_end();
++p)
{
Symbol* sym = this->lookup(p->c_str());
gold_assert(sym != NULL);
if (sym->source() == Symbol::FROM_OBJECT
&& !sym->object()->is_dynamic())
{
this->gc_mark_symbol(sym);
}
}
}
void
Symbol_table::gc_mark_symbol(Symbol* sym)
{
// Add the object and section to the work list.
bool is_ordinary;
unsigned int shndx = sym->shndx(&is_ordinary);
if (is_ordinary && shndx != elfcpp::SHN_UNDEF && !sym->object()->is_dynamic())
{
gold_assert(this->gc_!= NULL);
Relobj* relobj = static_cast<Relobj*>(sym->object());
this->gc_->worklist().push_back(Section_id(relobj, shndx));
}
parameters->target().gc_mark_symbol(this, sym);
}
// When doing garbage collection, keep symbols that have been seen in
// dynamic objects.
inline void
Symbol_table::gc_mark_dyn_syms(Symbol* sym)
{
if (sym->in_dyn() && sym->source() == Symbol::FROM_OBJECT
&& !sym->object()->is_dynamic())
this->gc_mark_symbol(sym);
}
// Make TO a symbol which forwards to FROM.
void
Symbol_table::make_forwarder(Symbol* from, Symbol* to)
{
gold_assert(from != to);
gold_assert(!from->is_forwarder() && !to->is_forwarder());
this->forwarders_[from] = to;
from->set_forwarder();
}
// Resolve the forwards from FROM, returning the real symbol.
Symbol*
Symbol_table::resolve_forwards(const Symbol* from) const
{
gold_assert(from->is_forwarder());
Unordered_map<const Symbol*, Symbol*>::const_iterator p =
this->forwarders_.find(from);
gold_assert(p != this->forwarders_.end());
return p->second;
}
// Look up a symbol by name.
Symbol*
Symbol_table::lookup(const char* name, const char* version) const
{
Stringpool::Key name_key;
name = this->namepool_.find(name, &name_key);
if (name == NULL)
return NULL;
Stringpool::Key version_key = 0;
if (version != NULL)
{
version = this->namepool_.find(version, &version_key);
if (version == NULL)
return NULL;
}
Symbol_table_key key(name_key, version_key);
Symbol_table::Symbol_table_type::const_iterator p = this->table_.find(key);
if (p == this->table_.end())
return NULL;
return p->second;
}
// Resolve a Symbol with another Symbol. This is only used in the
// unusual case where there are references to both an unversioned
// symbol and a symbol with a version, and we then discover that that
// version is the default version. Because this is unusual, we do
// this the slow way, by converting back to an ELF symbol.
template<int size, bool big_endian>
void
Symbol_table::resolve(Sized_symbol<size>* to, const Sized_symbol<size>* from)
{
unsigned char buf[elfcpp::Elf_sizes<size>::sym_size];
elfcpp::Sym_write<size, big_endian> esym(buf);
// We don't bother to set the st_name or the st_shndx field.
esym.put_st_value(from->value());
esym.put_st_size(from->symsize());
esym.put_st_info(from->binding(), from->type());
esym.put_st_other(from->visibility(), from->nonvis());
bool is_ordinary;
unsigned int shndx = from->shndx(&is_ordinary);
this->resolve(to, esym.sym(), shndx, is_ordinary, shndx, from->object(),
from->version(), true);
if (from->in_reg())
to->set_in_reg();
if (from->in_dyn())
to->set_in_dyn();
if (parameters->options().gc_sections())
this->gc_mark_dyn_syms(to);
}
// Record that a symbol is forced to be local by a version script or
// by visibility.
void
Symbol_table::force_local(Symbol* sym)
{
if (!sym->is_defined() && !sym->is_common())
return;
if (sym->is_forced_local())
{
// We already got this one.
return;
}
sym->set_is_forced_local();
this->forced_locals_.push_back(sym);
}
// Adjust NAME for wrapping, and update *NAME_KEY if necessary. This
// is only called for undefined symbols, when at least one --wrap
// option was used.
const char*
Symbol_table::wrap_symbol(const char* name, Stringpool::Key* name_key)
{
// For some targets, we need to ignore a specific character when
// wrapping, and add it back later.
char prefix = '\0';
if (name[0] == parameters->target().wrap_char())
{
prefix = name[0];
++name;
}
if (parameters->options().is_wrap(name))
{
// Turn NAME into __wrap_NAME.
std::string s;
if (prefix != '\0')
s += prefix;
s += "__wrap_";
s += name;
// This will give us both the old and new name in NAMEPOOL_, but
// that is OK. Only the versions we need will wind up in the
// real string table in the output file.
return this->namepool_.add(s.c_str(), true, name_key);
}
const char* const real_prefix = "__real_";
const size_t real_prefix_length = strlen(real_prefix);
if (strncmp(name, real_prefix, real_prefix_length) == 0
&& parameters->options().is_wrap(name + real_prefix_length))
{
// Turn __real_NAME into NAME.
std::string s;
if (prefix != '\0')
s += prefix;
s += name + real_prefix_length;
return this->namepool_.add(s.c_str(), true, name_key);
}
return name;
}
// This is called when we see a symbol NAME/VERSION, and the symbol
// already exists in the symbol table, and VERSION is marked as being
// the default version. SYM is the NAME/VERSION symbol we just added.
// DEFAULT_IS_NEW is true if this is the first time we have seen the
// symbol NAME/NULL. PDEF points to the entry for NAME/NULL.
template<int size, bool big_endian>
void
Symbol_table::define_default_version(Sized_symbol<size>* sym,
bool default_is_new,
Symbol_table_type::iterator pdef)
{
if (default_is_new)
{
// This is the first time we have seen NAME/NULL. Make
// NAME/NULL point to NAME/VERSION, and mark SYM as the default
// version.
pdef->second = sym;
sym->set_is_default();
}
else if (pdef->second == sym)
{
// NAME/NULL already points to NAME/VERSION. Don't mark the
// symbol as the default if it is not already the default.
}
else
{
// This is the unfortunate case where we already have entries
// for both NAME/VERSION and NAME/NULL. We now see a symbol
// NAME/VERSION where VERSION is the default version. We have
// already resolved this new symbol with the existing
// NAME/VERSION symbol.
// It's possible that NAME/NULL and NAME/VERSION are both
// defined in regular objects. This can only happen if one
// object file defines foo and another defines foo@@ver. This
// is somewhat obscure, but we call it a multiple definition
// error.
// It's possible that NAME/NULL actually has a version, in which
// case it won't be the same as VERSION. This happens with
// ver_test_7.so in the testsuite for the symbol t2_2. We see
// t2_2@@VER2, so we define both t2_2/VER2 and t2_2/NULL. We
// then see an unadorned t2_2 in an object file and give it
// version VER1 from the version script. This looks like a
// default definition for VER1, so it looks like we should merge
// t2_2/NULL with t2_2/VER1. That doesn't make sense, but it's
// not obvious that this is an error, either. So we just punt.
// If one of the symbols has non-default visibility, and the
// other is defined in a shared object, then they are different
// symbols.
// If the two symbols are from different shared objects,
// they are different symbols.
// Otherwise, we just resolve the symbols as though they were
// the same.
if (pdef->second->version() != NULL)
gold_assert(pdef->second->version() != sym->version());
else if (sym->visibility() != elfcpp::STV_DEFAULT
&& pdef->second->is_from_dynobj())
;
else if (pdef->second->visibility() != elfcpp::STV_DEFAULT
&& sym->is_from_dynobj())
;
else if (pdef->second->is_from_dynobj()
&& sym->is_from_dynobj()
&& pdef->second->is_defined()
&& pdef->second->object() != sym->object())
;
else
{
const Sized_symbol<size>* symdef;
symdef = this->get_sized_symbol<size>(pdef->second);
Symbol_table::resolve<size, big_endian>(sym, symdef);
this->make_forwarder(pdef->second, sym);
pdef->second = sym;
sym->set_is_default();
}
}
}
// Add one symbol from OBJECT to the symbol table. NAME is symbol
// name and VERSION is the version; both are canonicalized. DEF is
// whether this is the default version. ST_SHNDX is the symbol's
// section index; IS_ORDINARY is whether this is a normal section
// rather than a special code.
// If IS_DEFAULT_VERSION is true, then this is the definition of a
// default version of a symbol. That means that any lookup of
// NAME/NULL and any lookup of NAME/VERSION should always return the
// same symbol. This is obvious for references, but in particular we
// want to do this for definitions: overriding NAME/NULL should also
// override NAME/VERSION. If we don't do that, it would be very hard
// to override functions in a shared library which uses versioning.
// We implement this by simply making both entries in the hash table
// point to the same Symbol structure. That is easy enough if this is
// the first time we see NAME/NULL or NAME/VERSION, but it is possible
// that we have seen both already, in which case they will both have
// independent entries in the symbol table. We can't simply change
// the symbol table entry, because we have pointers to the entries
// attached to the object files. So we mark the entry attached to the
// object file as a forwarder, and record it in the forwarders_ map.
// Note that entries in the hash table will never be marked as
// forwarders.
//
// ORIG_ST_SHNDX and ST_SHNDX are almost always the same.
// ORIG_ST_SHNDX is the section index in the input file, or SHN_UNDEF
// for a special section code. ST_SHNDX may be modified if the symbol
// is defined in a section being discarded.
template<int size, bool big_endian>
Sized_symbol<size>*
Symbol_table::add_from_object(Object* object,
const char* name,
Stringpool::Key name_key,
const char* version,
Stringpool::Key version_key,
bool is_default_version,
const elfcpp::Sym<size, big_endian>& sym,
unsigned int st_shndx,
bool is_ordinary,
unsigned int orig_st_shndx)
{
// Print a message if this symbol is being traced.
if (parameters->options().is_trace_symbol(name))
{
if (orig_st_shndx == elfcpp::SHN_UNDEF)
gold_info(_("%s: reference to %s"), object->name().c_str(), name);
else
gold_info(_("%s: definition of %s"), object->name().c_str(), name);
}
// For an undefined symbol, we may need to adjust the name using
// --wrap.
if (orig_st_shndx == elfcpp::SHN_UNDEF
&& parameters->options().any_wrap())
{
const char* wrap_name = this->wrap_symbol(name, &name_key);
if (wrap_name != name)
{
// If we see a reference to malloc with version GLIBC_2.0,
// and we turn it into a reference to __wrap_malloc, then we
// discard the version number. Otherwise the user would be
// required to specify the correct version for
// __wrap_malloc.
version = NULL;
version_key = 0;
name = wrap_name;
}
}
Symbol* const snull = NULL;
std::pair<typename Symbol_table_type::iterator, bool> ins =
this->table_.insert(std::make_pair(std::make_pair(name_key, version_key),
snull));
std::pair<typename Symbol_table_type::iterator, bool> insdefault =
std::make_pair(this->table_.end(), false);
if (is_default_version)
{
const Stringpool::Key vnull_key = 0;
insdefault = this->table_.insert(std::make_pair(std::make_pair(name_key,
vnull_key),
snull));
}
// ins.first: an iterator, which is a pointer to a pair.
// ins.first->first: the key (a pair of name and version).
// ins.first->second: the value (Symbol*).
// ins.second: true if new entry was inserted, false if not.
Sized_symbol<size>* ret = NULL;
bool was_undefined_in_reg;
bool was_common;
if (!ins.second)
{
// We already have an entry for NAME/VERSION.
ret = this->get_sized_symbol<size>(ins.first->second);
gold_assert(ret != NULL);
was_undefined_in_reg = ret->is_undefined() && ret->in_reg();
// Commons from plugins are just placeholders.
was_common = ret->is_common() && ret->object()->pluginobj() == NULL;
this->resolve(ret, sym, st_shndx, is_ordinary, orig_st_shndx, object,
version, is_default_version);
if (parameters->options().gc_sections())
this->gc_mark_dyn_syms(ret);
if (is_default_version)
this->define_default_version<size, big_endian>(ret, insdefault.second,
insdefault.first);
else
{
bool dummy;
if (version != NULL
&& ret->source() == Symbol::FROM_OBJECT
&& ret->object() == object
&& is_ordinary
&& ret->shndx(&dummy) == st_shndx
&& ret->is_default())
{
// We have seen NAME/VERSION already, and marked it as the
// default version, but now we see a definition for
// NAME/VERSION that is not the default version. This can
// happen when the assembler generates two symbols for
// a symbol as a result of a ".symver foo,foo@VER"
// directive. We see the first unversioned symbol and
// we may mark it as the default version (from a
// version script); then we see the second versioned
// symbol and we need to override the first.
// In any other case, the two symbols should have generated
// a multiple definition error.
// (See PR gold/18703.)
ret->set_is_not_default();
const Stringpool::Key vnull_key = 0;
this->table_.erase(std::make_pair(name_key, vnull_key));
}
}
}
else
{
// This is the first time we have seen NAME/VERSION.
gold_assert(ins.first->second == NULL);
if (is_default_version && !insdefault.second)
{
// We already have an entry for NAME/NULL. If we override
// it, then change it to NAME/VERSION.
ret = this->get_sized_symbol<size>(insdefault.first->second);
// If the existing symbol already has a version,
// don't override it with the new symbol.
// This should only happen when the new symbol
// is from a shared library.
if (ret->version() != NULL)
{
if (!object->is_dynamic())
{
gold_warning(_("%s: conflicting default version definition"
" for %s@@%s"),
object->name().c_str(), name, version);
if (ret->source() == Symbol::FROM_OBJECT)
gold_info(_("%s: %s: previous definition of %s@@%s here"),
program_name,
ret->object()->name().c_str(),
name, ret->version());
}
ret = NULL;
is_default_version = false;
}
else
{
was_undefined_in_reg = ret->is_undefined() && ret->in_reg();
// Commons from plugins are just placeholders.
was_common = (ret->is_common()
&& ret->object()->pluginobj() == NULL);
this->resolve(ret, sym, st_shndx, is_ordinary, orig_st_shndx,
object, version, is_default_version);
if (parameters->options().gc_sections())
this->gc_mark_dyn_syms(ret);
ins.first->second = ret;
}
}
if (ret == NULL)
{
was_undefined_in_reg = false;
was_common = false;
Sized_target<size, big_endian>* target =
parameters->sized_target<size, big_endian>();
if (!target->has_make_symbol())
ret = new Sized_symbol<size>();
else
{
ret = target->make_symbol(name, sym.get_st_type(), object,
st_shndx, sym.get_st_value());
if (ret == NULL)
{
// This means that we don't want a symbol table
// entry after all.
if (!is_default_version)
this->table_.erase(ins.first);
else
{
this->table_.erase(insdefault.first);
// Inserting INSDEFAULT invalidated INS.
this->table_.erase(std::make_pair(name_key,
version_key));
}
return NULL;
}
}
ret->init_object(name, version, object, sym, st_shndx, is_ordinary);
ins.first->second = ret;
if (is_default_version)
{
// This is the first time we have seen NAME/NULL. Point
// it at the new entry for NAME/VERSION.
gold_assert(insdefault.second);
insdefault.first->second = ret;
}
}
if (is_default_version)
ret->set_is_default();
}
// Record every time we see a new undefined symbol, to speed up archive
// groups. We only care about symbols undefined in regular objects here
// because undefined symbols only in dynamic objects should't trigger rescans.
if (!was_undefined_in_reg && ret->is_undefined() && ret->in_reg())
{
++this->saw_undefined_;
if (parameters->options().has_plugins())
parameters->options().plugins()->new_undefined_symbol(ret);
}
// Keep track of common symbols, to speed up common symbol
// allocation. Don't record commons from plugin objects;
// we need to wait until we see the real symbol in the
// replacement file.
if (!was_common && ret->is_common() && ret->object()->pluginobj() == NULL)
{
if (ret->type() == elfcpp::STT_TLS)
this->tls_commons_.push_back(ret);
else if (!is_ordinary
&& st_shndx == parameters->target().small_common_shndx())
this->small_commons_.push_back(ret);
else if (!is_ordinary
&& st_shndx == parameters->target().large_common_shndx())
this->large_commons_.push_back(ret);
else
this->commons_.push_back(ret);
}
// If we're not doing a relocatable link, then any symbol with
// hidden or internal visibility is local.
if ((ret->visibility() == elfcpp::STV_HIDDEN
|| ret->visibility() == elfcpp::STV_INTERNAL)
&& (ret->binding() == elfcpp::STB_GLOBAL
|| ret->binding() == elfcpp::STB_GNU_UNIQUE
|| ret->binding() == elfcpp::STB_WEAK)
&& !parameters->options().relocatable())
this->force_local(ret);
return ret;
}
// Add all the symbols in a relocatable object to the hash table.
template<int size, bool big_endian>
void
Symbol_table::add_from_relobj(
Sized_relobj_file<size, big_endian>* relobj,
const unsigned char* syms,
size_t count,
size_t symndx_offset,
const char* sym_names,
size_t sym_name_size,
typename Sized_relobj_file<size, big_endian>::Symbols* sympointers,
size_t* defined)
{
*defined = 0;
gold_assert(size == parameters->target().get_size());
const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
const bool just_symbols = relobj->just_symbols();
const unsigned char* p = syms;
for (size_t i = 0; i < count; ++i, p += sym_size)
{
(*sympointers)[i] = NULL;
elfcpp::Sym<size, big_endian> sym(p);
unsigned int st_name = sym.get_st_name();
if (st_name >= sym_name_size)
{
relobj->error(_("bad global symbol name offset %u at %zu"),
st_name, i);
continue;
}
const char* name = sym_names + st_name;
if (!parameters->options().relocatable()
&& name[0] == '_'
&& name[1] == '_'
&& strcmp (name + (name[2] == '_'), "__gnu_lto_slim") == 0)
gold_info(_("%s: plugin needed to handle lto object"),
relobj->name().c_str());
bool is_ordinary;
unsigned int st_shndx = relobj->adjust_sym_shndx(i + symndx_offset,
sym.get_st_shndx(),
&is_ordinary);
unsigned int orig_st_shndx = st_shndx;
if (!is_ordinary)
orig_st_shndx = elfcpp::SHN_UNDEF;
if (st_shndx != elfcpp::SHN_UNDEF)
++*defined;
// A symbol defined in a section which we are not including must
// be treated as an undefined symbol.
bool is_defined_in_discarded_section = false;
if (st_shndx != elfcpp::SHN_UNDEF
&& is_ordinary
&& !relobj->is_section_included(st_shndx)
&& !this->is_section_folded(relobj, st_shndx))
{
st_shndx = elfcpp::SHN_UNDEF;
is_defined_in_discarded_section = true;
}
// In an object file, an '@' in the name separates the symbol
// name from the version name. If there are two '@' characters,
// this is the default version.
const char* ver = strchr(name, '@');
Stringpool::Key ver_key = 0;
int namelen = 0;
// IS_DEFAULT_VERSION: is the version default?
// IS_FORCED_LOCAL: is the symbol forced local?
bool is_default_version = false;
bool is_forced_local = false;
// FIXME: For incremental links, we don't store version information,
// so we need to ignore version symbols for now.
if (parameters->incremental_update() && ver != NULL)
{
namelen = ver - name;
ver = NULL;
}
if (ver != NULL)
{
// The symbol name is of the form foo@VERSION or foo@@VERSION
namelen = ver - name;
++ver;
if (*ver == '@')
{
is_default_version = true;
++ver;
}
ver = this->namepool_.add(ver, true, &ver_key);
}
// We don't want to assign a version to an undefined symbol,
// even if it is listed in the version script. FIXME: What
// about a common symbol?
else
{
namelen = strlen(name);
if (!this->version_script_.empty()
&& st_shndx != elfcpp::SHN_UNDEF)
{
// The symbol name did not have a version, but the
// version script may assign a version anyway.
std::string version;
bool is_global;
if (this->version_script_.get_symbol_version(name, &version,
&is_global))
{
if (!is_global)
is_forced_local = true;
else if (!version.empty())
{
ver = this->namepool_.add_with_length(version.c_str(),
version.length(),
true,
&ver_key);
is_default_version = true;
}
}
}
}
elfcpp::Sym<size, big_endian>* psym = &sym;
unsigned char symbuf[sym_size];
elfcpp::Sym<size, big_endian> sym2(symbuf);
if (just_symbols)
{
memcpy(symbuf, p, sym_size);
elfcpp::Sym_write<size, big_endian> sw(symbuf);
if (orig_st_shndx != elfcpp::SHN_UNDEF
&& is_ordinary
&& relobj->e_type() == elfcpp::ET_REL)
{
// Symbol values in relocatable object files are section
// relative. This is normally what we want, but since here
// we are converting the symbol to absolute we need to add
// the section address. The section address in an object
// file is normally zero, but people can use a linker
// script to change it.
sw.put_st_value(sym.get_st_value()
+ relobj->section_address(orig_st_shndx));
}
st_shndx = elfcpp::SHN_ABS;
is_ordinary = false;
psym = &sym2;
}
// Fix up visibility if object has no-export set.
if (relobj->no_export()
&& (orig_st_shndx != elfcpp::SHN_UNDEF || !is_ordinary))
{
// We may have copied symbol already above.
if (psym != &sym2)
{
memcpy(symbuf, p, sym_size);
psym = &sym2;
}
elfcpp::STV visibility = sym2.get_st_visibility();
if (visibility == elfcpp::STV_DEFAULT
|| visibility == elfcpp::STV_PROTECTED)
{
elfcpp::Sym_write<size, big_endian> sw(symbuf);
unsigned char nonvis = sym2.get_st_nonvis();
sw.put_st_other(elfcpp::STV_HIDDEN, nonvis);
}
}
Stringpool::Key name_key;
name = this->namepool_.add_with_length(name, namelen, true,
&name_key);
Sized_symbol<size>* res;
res = this->add_from_object(relobj, name, name_key, ver, ver_key,
is_default_version, *psym, st_shndx,
is_ordinary, orig_st_shndx);
if (res == NULL)
continue;
if (is_forced_local)
this->force_local(res);
// Do not treat this symbol as garbage if this symbol will be
// exported to the dynamic symbol table. This is true when
// building a shared library or using --export-dynamic and
// the symbol is externally visible.
if (parameters->options().gc_sections()
&& res->is_externally_visible()
&& !res->is_from_dynobj()
&& (parameters->options().shared()
|| parameters->options().export_dynamic()
|| parameters->options().in_dynamic_list(res->name())))
this->gc_mark_symbol(res);
if (is_defined_in_discarded_section)
res->set_is_defined_in_discarded_section();
(*sympointers)[i] = res;
}
}
// Add a symbol from a plugin-claimed file.
template<int size, bool big_endian>
Symbol*
Symbol_table::add_from_pluginobj(
Sized_pluginobj<size, big_endian>* obj,
const char* name,
const char* ver,
elfcpp::Sym<size, big_endian>* sym)
{
unsigned int st_shndx = sym->get_st_shndx();
bool is_ordinary = st_shndx < elfcpp::SHN_LORESERVE;
Stringpool::Key ver_key = 0;
bool is_default_version = false;
bool is_forced_local = false;
if (ver != NULL)
{
ver = this->namepool_.add(ver, true, &ver_key);
}
// We don't want to assign a version to an undefined symbol,
// even if it is listed in the version script. FIXME: What
// about a common symbol?
else
{
if (!this->version_script_.empty()
&& st_shndx != elfcpp::SHN_UNDEF)
{
// The symbol name did not have a version, but the
// version script may assign a version anyway.
std::string version;
bool is_global;
if (this->version_script_.get_symbol_version(name, &version,
&is_global))
{
if (!is_global)
is_forced_local = true;
else if (!version.empty())
{
ver = this->namepool_.add_with_length(version.c_str(),
version.length(),
true,
&ver_key);
is_default_version = true;
}
}
}
}
Stringpool::Key name_key;
name = this->namepool_.add(name, true, &name_key);
Sized_symbol<size>* res;
res = this->add_from_object(obj, name, name_key, ver, ver_key,
is_default_version, *sym, st_shndx,
is_ordinary, st_shndx);
if (res == NULL)
return NULL;
if (is_forced_local)
this->force_local(res);
return res;
}
// Add all the symbols in a dynamic object to the hash table.
template<int size, bool big_endian>
void
Symbol_table::add_from_dynobj(
Sized_dynobj<size, big_endian>* dynobj,
const unsigned char* syms,
size_t count,
const char* sym_names,
size_t sym_name_size,
const unsigned char* versym,
size_t versym_size,
const std::vector<const char*>* version_map,
typename Sized_relobj_file<size, big_endian>::Symbols* sympointers,
size_t* defined)
{
*defined = 0;
gold_assert(size == parameters->target().get_size());
if (dynobj->just_symbols())
{
gold_error(_("--just-symbols does not make sense with a shared object"));
return;
}
// FIXME: For incremental links, we don't store version information,
// so we need to ignore version symbols for now.
if (parameters->incremental_update())
versym = NULL;
if (versym != NULL && versym_size / 2 < count)
{
dynobj->error(_("too few symbol versions"));
return;
}
const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
// We keep a list of all STT_OBJECT symbols, so that we can resolve
// weak aliases. This is necessary because if the dynamic object
// provides the same variable under two names, one of which is a
// weak definition, and the regular object refers to the weak
// definition, we have to put both the weak definition and the
// strong definition into the dynamic symbol table. Given a weak
// definition, the only way that we can find the corresponding
// strong definition, if any, is to search the symbol table.
std::vector<Sized_symbol<size>*> object_symbols;
const unsigned char* p = syms;
const unsigned char* vs = versym;
for (size_t i = 0; i < count; ++i, p += sym_size, vs += 2)
{
elfcpp::Sym<size, big_endian> sym(p);
if (sympointers != NULL)
(*sympointers)[i] = NULL;
// Ignore symbols with local binding or that have
// internal or hidden visibility.
if (sym.get_st_bind() == elfcpp::STB_LOCAL
|| sym.get_st_visibility() == elfcpp::STV_INTERNAL
|| sym.get_st_visibility() == elfcpp::STV_HIDDEN)
continue;
// A protected symbol in a shared library must be treated as a
// normal symbol when viewed from outside the shared library.
// Implement this by overriding the visibility here.
// Likewise, an IFUNC symbol in a shared library must be treated
// as a normal FUNC symbol.
elfcpp::Sym<size, big_endian>* psym = &sym;
unsigned char symbuf[sym_size];
elfcpp::Sym<size, big_endian> sym2(symbuf);
if (sym.get_st_visibility() == elfcpp::STV_PROTECTED
|| sym.get_st_type() == elfcpp::STT_GNU_IFUNC)
{
memcpy(symbuf, p, sym_size);
elfcpp::Sym_write<size, big_endian> sw(symbuf);
if (sym.get_st_visibility() == elfcpp::STV_PROTECTED)
sw.put_st_other(elfcpp::STV_DEFAULT, sym.get_st_nonvis());
if (sym.get_st_type() == elfcpp::STT_GNU_IFUNC)
sw.put_st_info(sym.get_st_bind(), elfcpp::STT_FUNC);
psym = &sym2;
}
unsigned int st_name = psym->get_st_name();
if (st_name >= sym_name_size)
{
dynobj->error(_("bad symbol name offset %u at %zu"),
st_name, i);
continue;
}
const char* name = sym_names + st_name;
bool is_ordinary;
unsigned int st_shndx = dynobj->adjust_sym_shndx(i, psym->get_st_shndx(),
&is_ordinary);
if (st_shndx != elfcpp::SHN_UNDEF)
++*defined;
Sized_symbol<size>* res;
if (versym == NULL)
{
Stringpool::Key name_key;
name = this->namepool_.add(name, true, &name_key);
res = this->add_from_object(dynobj, name, name_key, NULL, 0,
false, *psym, st_shndx, is_ordinary,
st_shndx);
}
else
{
// Read the version information.
unsigned int v = elfcpp::Swap<16, big_endian>::readval(vs);
bool hidden = (v & elfcpp::VERSYM_HIDDEN) != 0;
v &= elfcpp::VERSYM_VERSION;
// The Sun documentation says that V can be VER_NDX_LOCAL,
// or VER_NDX_GLOBAL, or a version index. The meaning of
// VER_NDX_LOCAL is defined as "Symbol has local scope."
// The old GNU linker will happily generate VER_NDX_LOCAL
// for an undefined symbol. I don't know what the Sun
// linker will generate.
if (v == static_cast<unsigned int>(elfcpp::VER_NDX_LOCAL)
&& st_shndx != elfcpp::SHN_UNDEF)
{
// This symbol should not be visible outside the object.
continue;
}
// At this point we are definitely going to add this symbol.
Stringpool::Key name_key;
name = this->namepool_.add(name, true, &name_key);
if (v == static_cast<unsigned int>(elfcpp::VER_NDX_LOCAL)
|| v == static_cast<unsigned int>(elfcpp::VER_NDX_GLOBAL))
{
// This symbol does not have a version.
res = this->add_from_object(dynobj, name, name_key, NULL, 0,
false, *psym, st_shndx, is_ordinary,
st_shndx);
}
else
{
if (v >= version_map->size())
{
dynobj->error(_("versym for symbol %zu out of range: %u"),
i, v);
continue;
}
const char* version = (*version_map)[v];
if (version == NULL)
{
dynobj->error(_("versym for symbol %zu has no name: %u"),
i, v);
continue;
}
Stringpool::Key version_key;
version = this->namepool_.add(version, true, &version_key);
// If this is an absolute symbol, and the version name
// and symbol name are the same, then this is the
// version definition symbol. These symbols exist to
// support using -u to pull in particular versions. We
// do not want to record a version for them.
if (st_shndx == elfcpp::SHN_ABS
&& !is_ordinary
&& name_key == version_key)
res = this->add_from_object(dynobj, name, name_key, NULL, 0,
false, *psym, st_shndx, is_ordinary,
st_shndx);
else
{
const bool is_default_version =
!hidden && st_shndx != elfcpp::SHN_UNDEF;
res = this->add_from_object(dynobj, name, name_key, version,
version_key, is_default_version,
*psym, st_shndx,
is_ordinary, st_shndx);
}
}
}
if (res == NULL)
continue;
// Note that it is possible that RES was overridden by an
// earlier object, in which case it can't be aliased here.
if (st_shndx != elfcpp::SHN_UNDEF
&& is_ordinary
&& psym->get_st_type() == elfcpp::STT_OBJECT
&& res->source() == Symbol::FROM_OBJECT
&& res->object() == dynobj)
object_symbols.push_back(res);
// If the symbol has protected visibility in the dynobj,
// mark it as such if it was not overridden.
if (res->source() == Symbol::FROM_OBJECT
&& res->object() == dynobj
&& sym.get_st_visibility() == elfcpp::STV_PROTECTED)
res->set_is_protected();
if (sympointers != NULL)
(*sympointers)[i] = res;
}
this->record_weak_aliases(&object_symbols);
}
// Add a symbol from a incremental object file.
template<int size, bool big_endian>
Sized_symbol<size>*
Symbol_table::add_from_incrobj(
Object* obj,
const char* name,
const char* ver,
elfcpp::Sym<size, big_endian>* sym)
{
unsigned int st_shndx = sym->get_st_shndx();
bool is_ordinary = st_shndx < elfcpp::SHN_LORESERVE;
Stringpool::Key ver_key = 0;
bool is_default_version = false;
Stringpool::Key name_key;
name = this->namepool_.add(name, true, &name_key);
Sized_symbol<size>* res;
res = this->add_from_object(obj, name, name_key, ver, ver_key,
is_default_version, *sym, st_shndx,
is_ordinary, st_shndx);
return res;
}
// This is used to sort weak aliases. We sort them first by section
// index, then by offset, then by weak ahead of strong.
template<int size>
class Weak_alias_sorter
{
public:
bool operator()(const Sized_symbol<size>*, const Sized_symbol<size>*) const;
};
template<int size>
bool
Weak_alias_sorter<size>::operator()(const Sized_symbol<size>* s1,
const Sized_symbol<size>* s2) const
{
bool is_ordinary;
unsigned int s1_shndx = s1->shndx(&is_ordinary);
gold_assert(is_ordinary);
unsigned int s2_shndx = s2->shndx(&is_ordinary);
gold_assert(is_ordinary);
if (s1_shndx != s2_shndx)
return s1_shndx < s2_shndx;
if (s1->value() != s2->value())
return s1->value() < s2->value();
if (s1->binding() != s2->binding())
{
if (s1->binding() == elfcpp::STB_WEAK)
return true;
if (s2->binding() == elfcpp::STB_WEAK)
return false;
}
return std::string(s1->name()) < std::string(s2->name());
}
// SYMBOLS is a list of object symbols from a dynamic object. Look
// for any weak aliases, and record them so that if we add the weak
// alias to the dynamic symbol table, we also add the corresponding
// strong symbol.
template<int size>
void
Symbol_table::record_weak_aliases(std::vector<Sized_symbol<size>*>* symbols)
{
// Sort the vector by section index, then by offset, then by weak
// ahead of strong.
std::sort(symbols->begin(), symbols->end(), Weak_alias_sorter<size>());
// Walk through the vector. For each weak definition, record
// aliases.
for (typename std::vector<Sized_symbol<size>*>::const_iterator p =
symbols->begin();
p != symbols->end();
++p)
{
if ((*p)->binding() != elfcpp::STB_WEAK)
continue;
// Build a circular list of weak aliases. Each symbol points to
// the next one in the circular list.
Sized_symbol<size>* from_sym = *p;
typename std::vector<Sized_symbol<size>*>::const_iterator q;
for (q = p + 1; q != symbols->end(); ++q)
{
bool dummy;
if ((*q)->shndx(&dummy) != from_sym->shndx(&dummy)
|| (*q)->value() != from_sym->value())
break;
this->weak_aliases_[from_sym] = *q;
from_sym->set_has_alias();
from_sym = *q;
}
if (from_sym != *p)
{
this->weak_aliases_[from_sym] = *p;
from_sym->set_has_alias();
}
p = q - 1;
}
}
// Create and return a specially defined symbol. If ONLY_IF_REF is
// true, then only create the symbol if there is a reference to it.
// If this does not return NULL, it sets *POLDSYM to the existing
// symbol if there is one. This sets *RESOLVE_OLDSYM if we should
// resolve the newly created symbol to the old one. This
// canonicalizes *PNAME and *PVERSION.
template<int size, bool big_endian>
Sized_symbol<size>*
Symbol_table::define_special_symbol(const char** pname, const char** pversion,
bool only_if_ref,
elfcpp::STV visibility,
Sized_symbol<size>** poldsym,
bool* resolve_oldsym, bool is_forced_local)
{
*resolve_oldsym = false;
*poldsym = NULL;
// If the caller didn't give us a version, see if we get one from
// the version script.
std::string v;
bool is_default_version = false;
if (!is_forced_local && *pversion == NULL)
{
bool is_global;
if (this->version_script_.get_symbol_version(*pname, &v, &is_global))
{
if (is_global && !v.empty())
{
*pversion = v.c_str();
// If we get the version from a version script, then we
// are also the default version.
is_default_version = true;
}
}
}
Symbol* oldsym;
Sized_symbol<size>* sym;
bool add_to_table = false;
typename Symbol_table_type::iterator add_loc = this->table_.end();
bool add_def_to_table = false;
typename Symbol_table_type::iterator add_def_loc = this->table_.end();
if (only_if_ref)
{
oldsym = this->lookup(*pname, *pversion);
if (oldsym == NULL && is_default_version)
oldsym = this->lookup(*pname, NULL);
if (oldsym == NULL)
return NULL;
if (!oldsym->is_undefined())
{
// Skip if the old definition is from a regular object.
if (!oldsym->is_from_dynobj())
return NULL;
// If the symbol has hidden or internal visibility, ignore
// definition and reference from a dynamic object.
if ((visibility == elfcpp::STV_HIDDEN
|| visibility == elfcpp::STV_INTERNAL)
&& !oldsym->in_reg())
return NULL;
}
*pname = oldsym->name();
if (is_default_version)
*pversion = this->namepool_.add(*pversion, true, NULL);
else
*pversion = oldsym->version();
}
else
{
// Canonicalize NAME and VERSION.
Stringpool::Key name_key;
*pname = this->namepool_.add(*pname, true, &name_key);
Stringpool::Key version_key = 0;
if (*pversion != NULL)
*pversion = this->namepool_.add(*pversion, true, &version_key);
Symbol* const snull = NULL;
std::pair<typename Symbol_table_type::iterator, bool> ins =
this->table_.insert(std::make_pair(std::make_pair(name_key,
version_key),
snull));
std::pair<typename Symbol_table_type::iterator, bool> insdefault =
std::make_pair(this->table_.end(), false);
if (is_default_version)
{
const Stringpool::Key vnull = 0;
insdefault =
this->table_.insert(std::make_pair(std::make_pair(name_key,
vnull),
snull));
}
if (!ins.second)
{
// We already have a symbol table entry for NAME/VERSION.
oldsym = ins.first->second;
gold_assert(oldsym != NULL);
if (is_default_version)
{
Sized_symbol<size>* soldsym =
this->get_sized_symbol<size>(oldsym);
this->define_default_version<size, big_endian>(soldsym,
insdefault.second,
insdefault.first);
}
}
else
{
// We haven't seen this symbol before.
gold_assert(ins.first->second == NULL);
add_to_table = true;
add_loc = ins.first;
if (is_default_version
&& !insdefault.second
&& insdefault.first->second->version() == NULL)
{
// We are adding NAME/VERSION, and it is the default
// version. We already have an entry for NAME/NULL
// that does not already have a version.
oldsym = insdefault.first->second;
*resolve_oldsym = true;
}
else
{
oldsym = NULL;
if (is_default_version)
{
add_def_to_table = true;
add_def_loc = insdefault.first;
}
}
}
}
const Target& target = parameters->target();
if (!target.has_make_symbol())
sym = new Sized_symbol<size>();
else
{
Sized_target<size, big_endian>* sized_target =
parameters->sized_target<size, big_endian>();
sym = sized_target->make_symbol(*pname, elfcpp::STT_NOTYPE,
NULL, elfcpp::SHN_UNDEF, 0);
if (sym == NULL)
return NULL;
}
if (add_to_table)
add_loc->second = sym;
else
gold_assert(oldsym != NULL);
if (add_def_to_table)
add_def_loc->second = sym;
*poldsym = this->get_sized_symbol<size>(oldsym);
return sym;
}
// Define a symbol based on an Output_data.
Symbol*
Symbol_table::define_in_output_data(const char* name,
const char* version,
Defined defined,
Output_data* od,
uint64_t value,
uint64_t symsize,
elfcpp::STT type,
elfcpp::STB binding,
elfcpp::STV visibility,
unsigned char nonvis,
bool offset_is_from_end,
bool only_if_ref)
{
if (parameters->target().get_size() == 32)
{
#if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
return this->do_define_in_output_data<32>(name, version, defined, od,
value, symsize, type, binding,
visibility, nonvis,
offset_is_from_end,
only_if_ref);
#else
gold_unreachable();
#endif
}
else if (parameters->target().get_size() == 64)
{
#if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
return this->do_define_in_output_data<64>(name, version, defined, od,
value, symsize, type, binding,
visibility, nonvis,
offset_is_from_end,
only_if_ref);
#else
gold_unreachable();
#endif
}
else
gold_unreachable();
}
// Define a symbol in an Output_data, sized version.
template<int size>
Sized_symbol<size>*
Symbol_table::do_define_in_output_data(
const char* name,
const char* version,
Defined defined,
Output_data* od,
typename elfcpp::Elf_types<size>::Elf_Addr value,
typename elfcpp::Elf_types<size>::Elf_WXword symsize,
elfcpp::STT type,
elfcpp::STB binding,
elfcpp::STV visibility,
unsigned char nonvis,
bool offset_is_from_end,
bool only_if_ref)
{
Sized_symbol<size>* sym;
Sized_symbol<size>* oldsym;
bool resolve_oldsym;
const bool is_forced_local = binding == elfcpp::STB_LOCAL;
if (parameters->target().is_big_endian())
{
#if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
sym = this->define_special_symbol<size, true>(&name, &version,
only_if_ref,
visibility,
&oldsym,
&resolve_oldsym,
is_forced_local);
#else
gold_unreachable();
#endif
}
else
{
#if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
sym = this->define_special_symbol<size, false>(&name, &version,
only_if_ref,
visibility,
&oldsym,
&resolve_oldsym,
is_forced_local);
#else
gold_unreachable();
#endif
}
if (sym == NULL)
return NULL;
sym->init_output_data(name, version, od, value, symsize, type, binding,
visibility, nonvis, offset_is_from_end,
defined == PREDEFINED);
if (oldsym == NULL)
{
if (is_forced_local || this->version_script_.symbol_is_local(name))
this->force_local(sym);
else if (version != NULL)
sym->set_is_default();
return sym;
}
if (Symbol_table::should_override_with_special(oldsym, type, defined))
this->override_with_special(oldsym, sym);
if (resolve_oldsym)
return sym;
else
{
if (defined == PREDEFINED
&& (is_forced_local || this->version_script_.symbol_is_local(name)))
this->force_local(oldsym);
delete sym;
return oldsym;
}
}
// Define a symbol based on an Output_segment.
Symbol*
Symbol_table::define_in_output_segment(const char* name,
const char* version,
Defined defined,
Output_segment* os,
uint64_t value,
uint64_t symsize,
elfcpp::STT type,
elfcpp::STB binding,
elfcpp::STV visibility,
unsigned char nonvis,
Symbol::Segment_offset_base offset_base,
bool only_if_ref)
{
if (parameters->target().get_size() == 32)
{
#if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
return this->do_define_in_output_segment<32>(name, version, defined, os,
value, symsize, type,
binding, visibility, nonvis,
offset_base, only_if_ref);
#else
gold_unreachable();
#endif
}
else if (parameters->target().get_size() == 64)
{
#if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
return this->do_define_in_output_segment<64>(name, version, defined, os,
value, symsize, type,
binding, visibility, nonvis,
offset_base, only_if_ref);
#else
gold_unreachable();
#endif
}
else
gold_unreachable();
}
// Define a symbol in an Output_segment, sized version.
template<int size>
Sized_symbol<size>*
Symbol_table::do_define_in_output_segment(
const char* name,
const char* version,
Defined defined,
Output_segment* os,
typename elfcpp::Elf_types<size>::Elf_Addr value,
typename elfcpp::Elf_types<size>::Elf_WXword symsize,
elfcpp::STT type,
elfcpp::STB binding,
elfcpp::STV visibility,
unsigned char nonvis,
Symbol::Segment_offset_base offset_base,
bool only_if_ref)
{
Sized_symbol<size>* sym;
Sized_symbol<size>* oldsym;
bool resolve_oldsym;
const bool is_forced_local = binding == elfcpp::STB_LOCAL;
if (parameters->target().is_big_endian())
{
#if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
sym = this->define_special_symbol<size, true>(&name, &version,
only_if_ref,
visibility,
&oldsym,
&resolve_oldsym,
is_forced_local);
#else
gold_unreachable();
#endif
}
else
{
#if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
sym = this->define_special_symbol<size, false>(&name, &version,
only_if_ref,
visibility,
&oldsym,
&resolve_oldsym,
is_forced_local);
#else
gold_unreachable();
#endif
}
if (sym == NULL)
return NULL;
sym->init_output_segment(name, version, os, value, symsize, type, binding,
visibility, nonvis, offset_base,
defined == PREDEFINED);
if (oldsym == NULL)
{
if (is_forced_local || this->version_script_.symbol_is_local(name))
this->force_local(sym);
else if (version != NULL)
sym->set_is_default();
return sym;
}
if (Symbol_table::should_override_with_special(oldsym, type, defined))
this->override_with_special(oldsym, sym);
if (resolve_oldsym)
return sym;
else
{
if (is_forced_local || this->version_script_.symbol_is_local(name))
this->force_local(oldsym);
delete sym;
return oldsym;
}
}
// Define a special symbol with a constant value. It is a multiple
// definition error if this symbol is already defined.
Symbol*
Symbol_table::define_as_constant(const char* name,
const char* version,
Defined defined,
uint64_t value,
uint64_t symsize,
elfcpp::STT type,
elfcpp::STB binding,
elfcpp::STV visibility,
unsigned char nonvis,
bool only_if_ref,
bool force_override)
{
if (parameters->target().get_size() == 32)
{
#if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
return this->do_define_as_constant<32>(name, version, defined, value,
symsize, type, binding,
visibility, nonvis, only_if_ref,
force_override);
#else
gold_unreachable();
#endif
}
else if (parameters->target().get_size() == 64)
{
#if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
return this->do_define_as_constant<64>(name, version, defined, value,
symsize, type, binding,
visibility, nonvis, only_if_ref,
force_override);
#else
gold_unreachable();
#endif
}
else
gold_unreachable();
}
// Define a symbol as a constant, sized version.
template<int size>
Sized_symbol<size>*
Symbol_table::do_define_as_constant(
const char* name,
const char* version,
Defined defined,
typename elfcpp::Elf_types<size>::Elf_Addr value,
typename elfcpp::Elf_types<size>::Elf_WXword symsize,
elfcpp::STT type,
elfcpp::STB binding,
elfcpp::STV visibility,
unsigned char nonvis,
bool only_if_ref,
bool force_override)
{
Sized_symbol<size>* sym;
Sized_symbol<size>* oldsym;
bool resolve_oldsym;
const bool is_forced_local = binding == elfcpp::STB_LOCAL;
if (parameters->target().is_big_endian())
{
#if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
sym = this->define_special_symbol<size, true>(&name, &version,
only_if_ref,
visibility,
&oldsym,
&resolve_oldsym,
is_forced_local);
#else
gold_unreachable();
#endif
}
else
{
#if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
sym = this->define_special_symbol<size, false>(&name, &version,
only_if_ref,
visibility,
&oldsym,
&resolve_oldsym,
is_forced_local);
#else
gold_unreachable();
#endif
}
if (sym == NULL)
return NULL;
sym->init_constant(name, version, value, symsize, type, binding, visibility,
nonvis, defined == PREDEFINED);
if (oldsym == NULL)
{
// Version symbols are absolute symbols with name == version.
// We don't want to force them to be local.
if ((version == NULL
|| name != version
|| value != 0)
&& (is_forced_local || this->version_script_.symbol_is_local(name)))
this->force_local(sym);
else if (version != NULL
&& (name != version || value != 0))
sym->set_is_default();
return sym;
}
if (force_override
|| Symbol_table::should_override_with_special(oldsym, type, defined))
this->override_with_special(oldsym, sym);
if (resolve_oldsym)
return sym;
else
{
if (is_forced_local || this->version_script_.symbol_is_local(name))
this->force_local(oldsym);
delete sym;
return oldsym;
}
}
// Define a set of symbols in output sections.
void
Symbol_table::define_symbols(const Layout* layout, int count,
const Define_symbol_in_section* p,
bool only_if_ref)
{
for (int i = 0; i < count; ++i, ++p)
{
Output_section* os = layout->find_output_section(p->output_section);
if (os != NULL)
this->define_in_output_data(p->name, NULL, PREDEFINED, os, p->value,
p->size, p->type, p->binding,
p->visibility, p->nonvis,
p->offset_is_from_end,
only_if_ref || p->only_if_ref);
else
this->define_as_constant(p->name, NULL, PREDEFINED, 0, p->size,
p->type, p->binding, p->visibility, p->nonvis,
only_if_ref || p->only_if_ref,
false);
}
}
// Define a set of symbols in output segments.
void
Symbol_table::define_symbols(const Layout* layout, int count,
const Define_symbol_in_segment* p,
bool only_if_ref)
{
for (int i = 0; i < count; ++i, ++p)
{
Output_segment* os = layout->find_output_segment(p->segment_type,
p->segment_flags_set,
p->segment_flags_clear);
if (os != NULL)
this->define_in_output_segment(p->name, NULL, PREDEFINED, os, p->value,
p->size, p->type, p->binding,
p->visibility, p->nonvis,
p->offset_base,
only_if_ref || p->only_if_ref);
else
this->define_as_constant(p->name, NULL, PREDEFINED, 0, p->size,
p->type, p->binding, p->visibility, p->nonvis,
only_if_ref || p->only_if_ref,
false);
}
}
// Define CSYM using a COPY reloc. POSD is the Output_data where the
// symbol should be defined--typically a .dyn.bss section. VALUE is
// the offset within POSD.
template<int size>
void
Symbol_table::define_with_copy_reloc(
Sized_symbol<size>* csym,
Output_data* posd,
typename elfcpp::Elf_types<size>::Elf_Addr value)
{
gold_assert(csym->is_from_dynobj());
gold_assert(!csym->is_copied_from_dynobj());
Object* object = csym->object();
gold_assert(object->is_dynamic());
Dynobj* dynobj = static_cast<Dynobj*>(object);
// Our copied variable has to override any variable in a shared
// library.
elfcpp::STB binding = csym->binding();
if (binding == elfcpp::STB_WEAK)
binding = elfcpp::STB_GLOBAL;
this->define_in_output_data(csym->name(), csym->version(), COPY,
posd, value, csym->symsize(),
csym->type(), binding,
csym->visibility(), csym->nonvis(),
false, false);
csym->set_is_copied_from_dynobj();
csym->set_needs_dynsym_entry();
this->copied_symbol_dynobjs_[csym] = dynobj;
// We have now defined all aliases, but we have not entered them all
// in the copied_symbol_dynobjs_ map.
if (csym->has_alias())
{
Symbol* sym = csym;
while (true)
{
sym = this->weak_aliases_[sym];
if (sym == csym)
break;
gold_assert(sym->output_data() == posd);
sym->set_is_copied_from_dynobj();
this->copied_symbol_dynobjs_[sym] = dynobj;
}
}
}
// SYM is defined using a COPY reloc. Return the dynamic object where
// the original definition was found.
Dynobj*
Symbol_table::get_copy_source(const Symbol* sym) const
{
gold_assert(sym->is_copied_from_dynobj());
Copied_symbol_dynobjs::const_iterator p =
this->copied_symbol_dynobjs_.find(sym);
gold_assert(p != this->copied_symbol_dynobjs_.end());
return p->second;
}
// Add any undefined symbols named on the command line.
void
Symbol_table::add_undefined_symbols_from_command_line(Layout* layout)
{
if (parameters->options().any_undefined()
|| layout->script_options()->any_unreferenced())
{
if (parameters->target().get_size() == 32)
{
#if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
this->do_add_undefined_symbols_from_command_line<32>(layout);
#else
gold_unreachable();
#endif
}
else if (parameters->target().get_size() == 64)
{
#if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
this->do_add_undefined_symbols_from_command_line<64>(layout);
#else
gold_unreachable();
#endif
}
else
gold_unreachable();
}
}
template<int size>
void
Symbol_table::do_add_undefined_symbols_from_command_line(Layout* layout)
{
for (options::String_set::const_iterator p =
parameters->options().undefined_begin();
p != parameters->options().undefined_end();
++p)
this->add_undefined_symbol_from_command_line<size>(p->c_str());
for (options::String_set::const_iterator p =
parameters->options().export_dynamic_symbol_begin();
p != parameters->options().export_dynamic_symbol_end();
++p)
this->add_undefined_symbol_from_command_line<size>(p->c_str());
for (Script_options::referenced_const_iterator p =
layout->script_options()->referenced_begin();
p != layout->script_options()->referenced_end();
++p)
this->add_undefined_symbol_from_command_line<size>(p->c_str());
}
template<int size>
void
Symbol_table::add_undefined_symbol_from_command_line(const char* name)
{
if (this->lookup(name) != NULL)
return;
const char* version = NULL;
Sized_symbol<size>* sym;
Sized_symbol<size>* oldsym;
bool resolve_oldsym;
if (parameters->target().is_big_endian())
{
#if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
sym = this->define_special_symbol<size, true>(&name, &version,
false,
elfcpp::STV_DEFAULT,
&oldsym,
&resolve_oldsym,
false);
#else
gold_unreachable();
#endif
}
else
{
#if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
sym = this->define_special_symbol<size, false>(&name, &version,
false,
elfcpp::STV_DEFAULT,
&oldsym,
&resolve_oldsym,
false);
#else
gold_unreachable();
#endif
}
gold_assert(oldsym == NULL);
sym->init_undefined(name, version, 0, elfcpp::STT_NOTYPE, elfcpp::STB_GLOBAL,
elfcpp::STV_DEFAULT, 0);
++this->saw_undefined_;
}
// Set the dynamic symbol indexes. INDEX is the index of the first
// global dynamic symbol. Pointers to the global symbols are stored
// into the vector SYMS. The names are added to DYNPOOL.
// This returns an updated dynamic symbol index.
unsigned int
Symbol_table::set_dynsym_indexes(unsigned int index,
unsigned int* pforced_local_count,
std::vector<Symbol*>* syms,
Stringpool* dynpool,
Versions* versions)
{
// First process all the symbols which have been forced to be local,
// as they must appear before all global symbols.
unsigned int forced_local_count = 0;
for (Forced_locals::iterator p = this->forced_locals_.begin();
p != this->forced_locals_.end();
++p)
{
Symbol* sym = *p;
gold_assert(sym->is_forced_local());
if (sym->has_dynsym_index())
continue;
if (!sym->should_add_dynsym_entry(this))
sym->set_dynsym_index(-1U);
else
{
sym->set_dynsym_index(index);
++index;
++forced_local_count;
dynpool->add(sym->name(), false, NULL);
}
}
*pforced_local_count = forced_local_count;
// Allow a target to set dynsym indexes.
if (parameters->target().has_custom_set_dynsym_indexes())
{
std::vector<Symbol*> dyn_symbols;
for (Symbol_table_type::iterator p = this->table_.begin();
p != this->table_.end();
++p)
{
Symbol* sym = p->second;
if (sym->is_forced_local())
continue;
if (!sym->should_add_dynsym_entry(this))
sym->set_dynsym_index(-1U);
else
dyn_symbols.push_back(sym);
}
return parameters->target().set_dynsym_indexes(&dyn_symbols, index, syms,
dynpool, versions, this);
}
for (Symbol_table_type::iterator p = this->table_.begin();
p != this->table_.end();
++p)
{
Symbol* sym = p->second;
if (sym->is_forced_local())
continue;
// Note that SYM may already have a dynamic symbol index, since
// some symbols appear more than once in the symbol table, with
// and without a version.
if (!sym->should_add_dynsym_entry(this))
sym->set_dynsym_index(-1U);
else if (!sym->has_dynsym_index())
{
sym->set_dynsym_index(index);
++index;
syms->push_back(sym);
dynpool->add(sym->name(), false, NULL);
// Record any version information, except those from
// as-needed libraries not seen to be needed. Note that the
// is_needed state for such libraries can change in this loop.
if (sym->version() != NULL)
{
if (!sym->is_from_dynobj()
|| !sym->object()->as_needed()
|| sym->object()->is_needed())
versions->record_version(this, dynpool, sym);
else
{
if (parameters->options().warn_drop_version())
gold_warning(_("discarding version information for "
"%s@%s, defined in unused shared library %s "
"(linked with --as-needed)"),
sym->name(), sym->version(),
sym->object()->name().c_str());
sym->clear_version();
}
}
}
}
// Finish up the versions. In some cases this may add new dynamic
// symbols.
index = versions->finalize(this, index, syms);
// Process target-specific symbols.
for (std::vector<Symbol*>::iterator p = this->target_symbols_.begin();
p != this->target_symbols_.end();
++p)
{
(*p)->set_dynsym_index(index);
++index;
syms->push_back(*p);
dynpool->add((*p)->name(), false, NULL);
}
return index;
}
// Set the final values for all the symbols. The index of the first
// global symbol in the output file is *PLOCAL_SYMCOUNT. Record the
// file offset OFF. Add their names to POOL. Return the new file
// offset. Update *PLOCAL_SYMCOUNT if necessary. DYNOFF and
// DYN_GLOBAL_INDEX refer to the start of the symbols that will be
// written from the global symbol table in Symtab::write_globals(),
// which will include forced-local symbols. DYN_GLOBAL_INDEX is
// not necessarily the same as the sh_info field for the .dynsym
// section, which will point to the first real global symbol.
off_t
Symbol_table::finalize(off_t off, off_t dynoff, size_t dyn_global_index,
size_t dyncount, Stringpool* pool,
unsigned int* plocal_symcount)
{
off_t ret;
gold_assert(*plocal_symcount != 0);
this->first_global_index_ = *plocal_symcount;
this->dynamic_offset_ = dynoff;
this->first_dynamic_global_index_ = dyn_global_index;
this->dynamic_count_ = dyncount;
if (parameters->target().get_size() == 32)
{
#if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_32_LITTLE)
ret = this->sized_finalize<32>(off, pool, plocal_symcount);
#else
gold_unreachable();
#endif
}
else if (parameters->target().get_size() == 64)
{
#if defined(HAVE_TARGET_64_BIG) || defined(HAVE_TARGET_64_LITTLE)
ret = this->sized_finalize<64>(off, pool, plocal_symcount);
#else
gold_unreachable();
#endif
}
else
gold_unreachable();
// Now that we have the final symbol table, we can reliably note
// which symbols should get warnings.
this->warnings_.note_warnings(this);
return ret;
}
// SYM is going into the symbol table at *PINDEX. Add the name to
// POOL, update *PINDEX and *POFF.
template<int size>
void
Symbol_table::add_to_final_symtab(Symbol* sym, Stringpool* pool,
unsigned int* pindex, off_t* poff)
{
sym->set_symtab_index(*pindex);
if (sym->version() == NULL || !parameters->options().relocatable())
pool->add(sym->name(), false, NULL);
else
pool->add(sym->versioned_name(), true, NULL);
++*pindex;
*poff += elfcpp::Elf_sizes<size>::sym_size;
}
// Set the final value for all the symbols. This is called after
// Layout::finalize, so all the output sections have their final
// address.
template<int size>
off_t
Symbol_table::sized_finalize(off_t off, Stringpool* pool,
unsigned int* plocal_symcount)
{
off = align_address(off, size >> 3);
this->offset_ = off;
unsigned int index = *plocal_symcount;
const unsigned int orig_index = index;
// First do all the symbols which have been forced to be local, as
// they must appear before all global symbols.
for (Forced_locals::iterator p = this->forced_locals_.begin();
p != this->forced_locals_.end();
++p)
{
Symbol* sym = *p;
gold_assert(sym->is_forced_local());
if (this->sized_finalize_symbol<size>(sym))
{
this->add_to_final_symtab<size>(sym, pool, &index, &off);
++*plocal_symcount;
}
}
// Now do all the remaining symbols.
for (Symbol_table_type::iterator p = this->table_.begin();
p != this->table_.end();
++p)
{
Symbol* sym = p->second;
if (this->sized_finalize_symbol<size>(sym))
this->add_to_final_symtab<size>(sym, pool, &index, &off);
}
// Now do target-specific symbols.
for (std::vector<Symbol*>::iterator p = this->target_symbols_.begin();
p != this->target_symbols_.end();
++p)
{
this->add_to_final_symtab<size>(*p, pool, &index, &off);
}
this->output_count_ = index - orig_index;
return off;
}
// Compute the final value of SYM and store status in location PSTATUS.
// During relaxation, this may be called multiple times for a symbol to
// compute its would-be final value in each relaxation pass.
template<int size>
typename Sized_symbol<size>::Value_type
Symbol_table::compute_final_value(
const Sized_symbol<size>* sym,
Compute_final_value_status* pstatus) const
{
typedef typename Sized_symbol<size>::Value_type Value_type;
Value_type value;
switch (sym->source())
{
case Symbol::FROM_OBJECT:
{
bool is_ordinary;
unsigned int shndx = sym->shndx(&is_ordinary);
if (!is_ordinary
&& shndx != elfcpp::SHN_ABS
&& !Symbol::is_common_shndx(shndx))
{
*pstatus = CFVS_UNSUPPORTED_SYMBOL_SECTION;
return 0;
}
Object* symobj = sym->object();
if (symobj->is_dynamic())
{
value = 0;
shndx = elfcpp::SHN_UNDEF;
}
else if (symobj->pluginobj() != NULL)
{
value = 0;
shndx = elfcpp::SHN_UNDEF;
}
else if (shndx == elfcpp::SHN_UNDEF)
value = 0;
else if (!is_ordinary
&& (shndx == elfcpp::SHN_ABS
|| Symbol::is_common_shndx(shndx)))
value = sym->value();
else
{
Relobj* relobj = static_cast<Relobj*>(symobj);
Output_section* os = relobj->output_section(shndx);
if (this->is_section_folded(relobj, shndx))
{
gold_assert(os == NULL);
// Get the os of the section it is folded onto.
Section_id folded = this->icf_->get_folded_section(relobj,
shndx);
gold_assert(folded.first != NULL);
Relobj* folded_obj = reinterpret_cast<Relobj*>(folded.first);
unsigned folded_shndx = folded.second;
os = folded_obj->output_section(folded_shndx);
gold_assert(os != NULL);
// Replace (relobj, shndx) with canonical ICF input section.
shndx = folded_shndx;
relobj = folded_obj;
}
uint64_t secoff64 = relobj->output_section_offset(shndx);
if (os == NULL)
{
bool static_or_reloc = (parameters->doing_static_link() ||
parameters->options().relocatable());
gold_assert(static_or_reloc || sym->dynsym_index() == -1U);
*pstatus = CFVS_NO_OUTPUT_SECTION;
return 0;
}
if (secoff64 == -1ULL)
{
// The section needs special handling (e.g., a merge section).
value = os->output_address(relobj, shndx, sym->value());
}
else
{
Value_type secoff =
convert_types<Value_type, uint64_t>(secoff64);
if (sym->type() == elfcpp::STT_TLS)
value = sym->value() + os->tls_offset() + secoff;
else
value = sym->value() + os->address() + secoff;
}
}
}
break;
case Symbol::IN_OUTPUT_DATA:
{
Output_data* od = sym->output_data();
value = sym->value();
if (sym->type() != elfcpp::STT_TLS)
value += od->address();
else
{
Output_section* os = od->output_section();
gold_assert(os != NULL);
value += os->tls_offset() + (od->address() - os->address());
}
if (sym->offset_is_from_end())
value += od->data_size();
}
break;
case Symbol::IN_OUTPUT_SEGMENT:
{
Output_segment* os = sym->output_segment();
value = sym->value();
if (sym->type() != elfcpp::STT_TLS)
value += os->vaddr();
switch (sym->offset_base())
{
case Symbol::SEGMENT_START:
break;
case Symbol::SEGMENT_END:
value += os->memsz();
break;
case Symbol::SEGMENT_BSS:
value += os->filesz();
break;
default:
gold_unreachable();
}
}
break;
case Symbol::IS_CONSTANT:
value = sym->value();
break;
case Symbol::IS_UNDEFINED:
value = 0;
break;
default:
gold_unreachable();
}
*pstatus = CFVS_OK;
return value;
}
// Finalize the symbol SYM. This returns true if the symbol should be
// added to the symbol table, false otherwise.
template<int size>
bool
Symbol_table::sized_finalize_symbol(Symbol* unsized_sym)
{
typedef typename Sized_symbol<size>::Value_type Value_type;
Sized_symbol<size>* sym = static_cast<Sized_symbol<size>*>(unsized_sym);
// The default version of a symbol may appear twice in the symbol
// table. We only need to finalize it once.
if (sym->has_symtab_index())
return false;
if (!sym->in_reg())
{
gold_assert(!sym->has_symtab_index());
sym->set_symtab_index(-1U);
gold_assert(sym->dynsym_index() == -1U);
return false;
}
// If the symbol is only present on plugin files, the plugin decided we
// don't need it.
if (!sym->in_real_elf())
{
gold_assert(!sym->has_symtab_index());
sym->set_symtab_index(-1U);
return false;
}
// Compute final symbol value.
Compute_final_value_status status;
Value_type value = this->compute_final_value(sym, &status);
switch (status)
{
case CFVS_OK:
break;
case CFVS_UNSUPPORTED_SYMBOL_SECTION:
{
bool is_ordinary;
unsigned int shndx = sym->shndx(&is_ordinary);
gold_error(_("%s: unsupported symbol section 0x%x"),
sym->demangled_name().c_str(), shndx);
}
break;
case CFVS_NO_OUTPUT_SECTION:
sym->set_symtab_index(-1U);
return false;
default:
gold_unreachable();
}
sym->set_value(value);
if (parameters->options().strip_all()
|| !parameters->options().should_retain_symbol(sym->name()))
{
sym->set_symtab_index(-1U);
return false;
}
return true;
}
// Write out the global symbols.
void
Symbol_table::write_globals(const Stringpool* sympool,
const Stringpool* dynpool,
Output_symtab_xindex* symtab_xindex,
Output_symtab_xindex* dynsym_xindex,
Output_file* of) const
{
switch (parameters->size_and_endianness())
{
#ifdef HAVE_TARGET_32_LITTLE
case Parameters::TARGET_32_LITTLE:
this->sized_write_globals<32, false>(sympool, dynpool, symtab_xindex,
dynsym_xindex, of);
break;
#endif
#ifdef HAVE_TARGET_32_BIG
case Parameters::TARGET_32_BIG:
this->sized_write_globals<32, true>(sympool, dynpool, symtab_xindex,
dynsym_xindex, of);
break;
#endif
#ifdef HAVE_TARGET_64_LITTLE
case Parameters::TARGET_64_LITTLE:
this->sized_write_globals<64, false>(sympool, dynpool, symtab_xindex,
dynsym_xindex, of);
break;
#endif
#ifdef HAVE_TARGET_64_BIG
case Parameters::TARGET_64_BIG:
this->sized_write_globals<64, true>(sympool, dynpool, symtab_xindex,
dynsym_xindex, of);
break;
#endif
default:
gold_unreachable();
}
}
// Write out the global symbols.
template<int size, bool big_endian>
void
Symbol_table::sized_write_globals(const Stringpool* sympool,
const Stringpool* dynpool,
Output_symtab_xindex* symtab_xindex,
Output_symtab_xindex* dynsym_xindex,
Output_file* of) const
{
const Target& target = parameters->target();
const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
const unsigned int output_count = this->output_count_;
const section_size_type oview_size = output_count * sym_size;
const unsigned int first_global_index = this->first_global_index_;
unsigned char* psyms;
if (this->offset_ == 0 || output_count == 0)
psyms = NULL;
else
psyms = of->get_output_view(this->offset_, oview_size);
const unsigned int dynamic_count = this->dynamic_count_;
const section_size_type dynamic_size = dynamic_count * sym_size;
const unsigned int first_dynamic_global_index =
this->first_dynamic_global_index_;
unsigned char* dynamic_view;
if (this->dynamic_offset_ == 0 || dynamic_count == 0)
dynamic_view = NULL;
else
dynamic_view = of->get_output_view(this->dynamic_offset_, dynamic_size);
for (Symbol_table_type::const_iterator p = this->table_.begin();
p != this->table_.end();
++p)
{
Sized_symbol<size>* sym = static_cast<Sized_symbol<size>*>(p->second);
// Possibly warn about unresolved symbols in shared libraries.
this->warn_about_undefined_dynobj_symbol(sym);
unsigned int sym_index = sym->symtab_index();
unsigned int dynsym_index;
if (dynamic_view == NULL)
dynsym_index = -1U;
else
dynsym_index = sym->dynsym_index();
if (sym_index == -1U && dynsym_index == -1U)
{
// This symbol is not included in the output file.
continue;
}
unsigned int shndx;
typename elfcpp::Elf_types<size>::Elf_Addr sym_value = sym->value();
typename elfcpp::Elf_types<size>::Elf_Addr dynsym_value = sym_value;
elfcpp::STB binding = sym->binding();
// If --weak-unresolved-symbols is set, change binding of unresolved
// global symbols to STB_WEAK.
if (parameters->options().weak_unresolved_symbols()
&& binding == elfcpp::STB_GLOBAL
&& sym->is_undefined())
binding = elfcpp::STB_WEAK;
// If --no-gnu-unique is set, change STB_GNU_UNIQUE to STB_GLOBAL.
if (binding == elfcpp::STB_GNU_UNIQUE
&& !parameters->options().gnu_unique())
binding = elfcpp::STB_GLOBAL;
switch (sym->source())
{
case Symbol::FROM_OBJECT:
{
bool is_ordinary;
unsigned int in_shndx = sym->shndx(&is_ordinary);
if (!is_ordinary
&& in_shndx != elfcpp::SHN_ABS
&& !Symbol::is_common_shndx(in_shndx))
{
gold_error(_("%s: unsupported symbol section 0x%x"),
sym->demangled_name().c_str(), in_shndx);
shndx = in_shndx;
}
else
{
Object* symobj = sym->object();
if (symobj->is_dynamic())
{
if (sym->needs_dynsym_value())
dynsym_value = target.dynsym_value(sym);
shndx = elfcpp::SHN_UNDEF;
if (sym->is_undef_binding_weak())
binding = elfcpp::STB_WEAK;
else
binding = elfcpp::STB_GLOBAL;
}
else if (symobj->pluginobj() != NULL)
shndx = elfcpp::SHN_UNDEF;
else if (in_shndx == elfcpp::SHN_UNDEF
|| (!is_ordinary
&& (in_shndx == elfcpp::SHN_ABS
|| Symbol::is_common_shndx(in_shndx))))
shndx = in_shndx;
else
{
Relobj* relobj = static_cast<Relobj*>(symobj);
Output_section* os = relobj->output_section(in_shndx);
if (this->is_section_folded(relobj, in_shndx))
{
// This global symbol must be written out even though
// it is folded.
// Get the os of the section it is folded onto.
Section_id folded =
this->icf_->get_folded_section(relobj, in_shndx);
gold_assert(folded.first !=NULL);
Relobj* folded_obj =
reinterpret_cast<Relobj*>(folded.first);
os = folded_obj->output_section(folded.second);
gold_assert(os != NULL);
}
gold_assert(os != NULL);
shndx = os->out_shndx();
if (shndx >= elfcpp::SHN_LORESERVE)
{
if (sym_index != -1U)
symtab_xindex->add(sym_index, shndx);
if (dynsym_index != -1U)
dynsym_xindex->add(dynsym_index, shndx);
shndx = elfcpp::SHN_XINDEX;
}
// In object files symbol values are section
// relative.
if (parameters->options().relocatable())
sym_value -= os->address();
}
}
}
break;
case Symbol::IN_OUTPUT_DATA:
{
Output_data* od = sym->output_data();
shndx = od->out_shndx();
if (shndx >= elfcpp::SHN_LORESERVE)
{
if (sym_index != -1U)
symtab_xindex->add(sym_index, shndx);
if (dynsym_index != -1U)
dynsym_xindex->add(dynsym_index, shndx);
shndx = elfcpp::SHN_XINDEX;
}
// In object files symbol values are section
// relative.
if (parameters->options().relocatable())
{
Output_section* os = od->output_section();
gold_assert(os != NULL);
sym_value -= os->address();
}
}
break;
case Symbol::IN_OUTPUT_SEGMENT:
{
Output_segment* oseg = sym->output_segment();
Output_section* osect = oseg->first_section();
if (osect == NULL)
shndx = elfcpp::SHN_ABS;
else
shndx = osect->out_shndx();
}
break;
case Symbol::IS_CONSTANT:
shndx = elfcpp::SHN_ABS;
break;
case Symbol::IS_UNDEFINED:
shndx = elfcpp::SHN_UNDEF;
break;
default:
gold_unreachable();
}
if (sym_index != -1U)
{
sym_index -= first_global_index;
gold_assert(sym_index < output_count);
unsigned char* ps = psyms + (sym_index * sym_size);
this->sized_write_symbol<size, big_endian>(sym, sym_value, shndx,
binding, sympool, ps);
}
if (dynsym_index != -1U)
{
dynsym_index -= first_dynamic_global_index;
gold_assert(dynsym_index < dynamic_count);
unsigned char* pd = dynamic_view + (dynsym_index * sym_size);
this->sized_write_symbol<size, big_endian>(sym, dynsym_value, shndx,
binding, dynpool, pd);
// Allow a target to adjust dynamic symbol value.
parameters->target().adjust_dyn_symbol(sym, pd);
}
}
// Write the target-specific symbols.
for (std::vector<Symbol*>::const_iterator p = this->target_symbols_.begin();
p != this->target_symbols_.end();
++p)
{
Sized_symbol<size>* sym = static_cast<Sized_symbol<size>*>(*p);
unsigned int sym_index = sym->symtab_index();
unsigned int dynsym_index;
if (dynamic_view == NULL)
dynsym_index = -1U;
else
dynsym_index = sym->dynsym_index();
unsigned int shndx;
switch (sym->source())
{
case Symbol::IS_CONSTANT:
shndx = elfcpp::SHN_ABS;
break;
case Symbol::IS_UNDEFINED:
shndx = elfcpp::SHN_UNDEF;
break;
default:
gold_unreachable();
}
if (sym_index != -1U)
{
sym_index -= first_global_index;
gold_assert(sym_index < output_count);
unsigned char* ps = psyms + (sym_index * sym_size);
this->sized_write_symbol<size, big_endian>(sym, sym->value(), shndx,
sym->binding(), sympool,
ps);
}
if (dynsym_index != -1U)
{
dynsym_index -= first_dynamic_global_index;
gold_assert(dynsym_index < dynamic_count);
unsigned char* pd = dynamic_view + (dynsym_index * sym_size);
this->sized_write_symbol<size, big_endian>(sym, sym->value(), shndx,
sym->binding(), dynpool,
pd);
}
}
of->write_output_view(this->offset_, oview_size, psyms);
if (dynamic_view != NULL)
of->write_output_view(this->dynamic_offset_, dynamic_size, dynamic_view);
}
// Write out the symbol SYM, in section SHNDX, to P. POOL is the
// strtab holding the name.
template<int size, bool big_endian>
void
Symbol_table::sized_write_symbol(
Sized_symbol<size>* sym,
typename elfcpp::Elf_types<size>::Elf_Addr value,
unsigned int shndx,
elfcpp::STB binding,
const Stringpool* pool,
unsigned char* p) const
{
elfcpp::Sym_write<size, big_endian> osym(p);
if (sym->version() == NULL || !parameters->options().relocatable())
osym.put_st_name(pool->get_offset(sym->name()));
else
osym.put_st_name(pool->get_offset(sym->versioned_name()));
osym.put_st_value(value);
// Use a symbol size of zero for undefined symbols from shared libraries.
if (shndx == elfcpp::SHN_UNDEF && sym->is_from_dynobj())
osym.put_st_size(0);
else
osym.put_st_size(sym->symsize());
elfcpp::STT type = sym->type();
gold_assert(type != elfcpp::STT_GNU_IFUNC || !sym->is_from_dynobj());
// A version script may have overridden the default binding.
if (sym->is_forced_local())
osym.put_st_info(elfcpp::elf_st_info(elfcpp::STB_LOCAL, type));
else
osym.put_st_info(elfcpp::elf_st_info(binding, type));
osym.put_st_other(elfcpp::elf_st_other(sym->visibility(), sym->nonvis()));
osym.put_st_shndx(shndx);
}
// Check for unresolved symbols in shared libraries. This is
// controlled by the --allow-shlib-undefined option.
// We only warn about libraries for which we have seen all the
// DT_NEEDED entries. We don't try to track down DT_NEEDED entries
// which were not seen in this link. If we didn't see a DT_NEEDED
// entry, we aren't going to be able to reliably report whether the
// symbol is undefined.
// We also don't warn about libraries found in a system library
// directory (e.g., /lib or /usr/lib); we assume that those libraries
// are OK. This heuristic avoids problems on GNU/Linux, in which -ldl
// can have undefined references satisfied by ld-linux.so.
inline void
Symbol_table::warn_about_undefined_dynobj_symbol(Symbol* sym) const
{
bool dummy;
if (sym->source() == Symbol::FROM_OBJECT
&& sym->object()->is_dynamic()
&& sym->shndx(&dummy) == elfcpp::SHN_UNDEF
&& sym->binding() != elfcpp::STB_WEAK
&& !parameters->options().allow_shlib_undefined()
&& !parameters->target().is_defined_by_abi(sym)
&& !sym->object()->is_in_system_directory())
{
// A very ugly cast.
Dynobj* dynobj = static_cast<Dynobj*>(sym->object());
if (!dynobj->has_unknown_needed_entries())
gold_undefined_symbol(sym);
}
}
// Write out a section symbol. Return the update offset.
void
Symbol_table::write_section_symbol(const Output_section* os,
Output_symtab_xindex* symtab_xindex,
Output_file* of,
off_t offset) const
{
switch (parameters->size_and_endianness())
{
#ifdef HAVE_TARGET_32_LITTLE
case Parameters::TARGET_32_LITTLE:
this->sized_write_section_symbol<32, false>(os, symtab_xindex, of,
offset);
break;
#endif
#ifdef HAVE_TARGET_32_BIG
case Parameters::TARGET_32_BIG:
this->sized_write_section_symbol<32, true>(os, symtab_xindex, of,
offset);
break;
#endif
#ifdef HAVE_TARGET_64_LITTLE
case Parameters::TARGET_64_LITTLE:
this->sized_write_section_symbol<64, false>(os, symtab_xindex, of,
offset);
break;
#endif
#ifdef HAVE_TARGET_64_BIG
case Parameters::TARGET_64_BIG:
this->sized_write_section_symbol<64, true>(os, symtab_xindex, of,
offset);
break;
#endif
default:
gold_unreachable();
}
}
// Write out a section symbol, specialized for size and endianness.
template<int size, bool big_endian>
void
Symbol_table::sized_write_section_symbol(const Output_section* os,
Output_symtab_xindex* symtab_xindex,
Output_file* of,
off_t offset) const
{
const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
unsigned char* pov = of->get_output_view(offset, sym_size);
elfcpp::Sym_write<size, big_endian> osym(pov);
osym.put_st_name(0);
if (parameters->options().relocatable())
osym.put_st_value(0);
else
osym.put_st_value(os->address());
osym.put_st_size(0);
osym.put_st_info(elfcpp::elf_st_info(elfcpp::STB_LOCAL,
elfcpp::STT_SECTION));
osym.put_st_other(elfcpp::elf_st_other(elfcpp::STV_DEFAULT, 0));
unsigned int shndx = os->out_shndx();
if (shndx >= elfcpp::SHN_LORESERVE)
{
symtab_xindex->add(os->symtab_index(), shndx);
shndx = elfcpp::SHN_XINDEX;
}
osym.put_st_shndx(shndx);
of->write_output_view(offset, sym_size, pov);
}
// Print statistical information to stderr. This is used for --stats.
void
Symbol_table::print_stats() const
{
#if defined(HAVE_TR1_UNORDERED_MAP) || defined(HAVE_EXT_HASH_MAP)
fprintf(stderr, _("%s: symbol table entries: %zu; buckets: %zu\n"),
program_name, this->table_.size(), this->table_.bucket_count());
#else
fprintf(stderr, _("%s: symbol table entries: %zu\n"),
program_name, this->table_.size());
#endif
this->namepool_.print_stats("symbol table stringpool");
}
// We check for ODR violations by looking for symbols with the same
// name for which the debugging information reports that they were
// defined in disjoint source locations. When comparing the source
// location, we consider instances with the same base filename to be
// the same. This is because different object files/shared libraries
// can include the same header file using different paths, and
// different optimization settings can make the line number appear to
// be a couple lines off, and we don't want to report an ODR violation
// in those cases.
// This struct is used to compare line information, as returned by
// Dwarf_line_info::one_addr2line. It implements a < comparison
// operator used with std::sort.
struct Odr_violation_compare
{
bool
operator()(const std::string& s1, const std::string& s2) const
{
// Inputs should be of the form "dirname/filename:linenum" where
// "dirname/" is optional. We want to compare just the filename:linenum.
// Find the last '/' in each string.
std::string::size_type s1begin = s1.rfind('/');
std::string::size_type s2begin = s2.rfind('/');
// If there was no '/' in a string, start at the beginning.
if (s1begin == std::string::npos)
s1begin = 0;
if (s2begin == std::string::npos)
s2begin = 0;
return s1.compare(s1begin, std::string::npos,
s2, s2begin, std::string::npos) < 0;
}
};
// Returns all of the lines attached to LOC, not just the one the
// instruction actually came from.
std::vector<std::string>
Symbol_table::linenos_from_loc(const Task* task,
const Symbol_location& loc)
{
// We need to lock the object in order to read it. This
// means that we have to run in a singleton Task. If we
// want to run this in a general Task for better
// performance, we will need one Task for object, plus
// appropriate locking to ensure that we don't conflict with
// other uses of the object. Also note, one_addr2line is not
// currently thread-safe.
Task_lock_obj<Object> tl(task, loc.object);
std::vector<std::string> result;
Symbol_location code_loc = loc;
parameters->target().function_location(&code_loc);
// 16 is the size of the object-cache that one_addr2line should use.
std::string canonical_result = Dwarf_line_info::one_addr2line(
code_loc.object, code_loc.shndx, code_loc.offset, 16, &result);
if (!canonical_result.empty())
result.push_back(canonical_result);
return result;
}
// OutputIterator that records if it was ever assigned to. This
// allows it to be used with std::set_intersection() to check for
// intersection rather than computing the intersection.
struct Check_intersection
{
Check_intersection()
: value_(false)
{}
bool had_intersection() const
{ return this->value_; }
Check_intersection& operator++()
{ return *this; }
Check_intersection& operator*()
{ return *this; }
template<typename T>
Check_intersection& operator=(const T&)
{
this->value_ = true;
return *this;
}
private:
bool value_;
};
// Check candidate_odr_violations_ to find symbols with the same name
// but apparently different definitions (different source-file/line-no
// for each line assigned to the first instruction).
void
Symbol_table::detect_odr_violations(const Task* task,
const char* output_file_name) const
{
for (Odr_map::const_iterator it = candidate_odr_violations_.begin();
it != candidate_odr_violations_.end();
++it)
{
const char* const symbol_name = it->first;
std::string first_object_name;
std::vector<std::string> first_object_linenos;
Unordered_set<Symbol_location, Symbol_location_hash>::const_iterator
locs = it->second.begin();
const Unordered_set<Symbol_location, Symbol_location_hash>::const_iterator
locs_end = it->second.end();
for (; locs != locs_end && first_object_linenos.empty(); ++locs)
{
// Save the line numbers from the first definition to
// compare to the other definitions. Ideally, we'd compare
// every definition to every other, but we don't want to
// take O(N^2) time to do this. This shortcut may cause
// false negatives that appear or disappear depending on the
// link order, but it won't cause false positives.
first_object_name = locs->object->name();
first_object_linenos = this->linenos_from_loc(task, *locs);
}
if (first_object_linenos.empty())
continue;
// Sort by Odr_violation_compare to make std::set_intersection work.
std::string first_object_canonical_result = first_object_linenos.back();
std::sort(first_object_linenos.begin(), first_object_linenos.end(),
Odr_violation_compare());
for (; locs != locs_end; ++locs)
{
std::vector<std::string> linenos =
this->linenos_from_loc(task, *locs);
// linenos will be empty if we couldn't parse the debug info.
if (linenos.empty())
continue;
// Sort by Odr_violation_compare to make std::set_intersection work.
gold_assert(!linenos.empty());
std::string second_object_canonical_result = linenos.back();
std::sort(linenos.begin(), linenos.end(), Odr_violation_compare());
Check_intersection intersection_result =
std::set_intersection(first_object_linenos.begin(),
first_object_linenos.end(),
linenos.begin(),
linenos.end(),
Check_intersection(),
Odr_violation_compare());
if (!intersection_result.had_intersection())
{
gold_warning(_("while linking %s: symbol '%s' defined in "
"multiple places (possible ODR violation):"),
output_file_name, demangle(symbol_name).c_str());
// This only prints one location from each definition,
// which may not be the location we expect to intersect
// with another definition. We could print the whole
// set of locations, but that seems too verbose.
fprintf(stderr, _(" %s from %s\n"),
first_object_canonical_result.c_str(),
first_object_name.c_str());
fprintf(stderr, _(" %s from %s\n"),
second_object_canonical_result.c_str(),
locs->object->name().c_str());
// Only print one broken pair, to avoid needing to
// compare against a list of the disjoint definition
// locations we've found so far. (If we kept comparing
// against just the first one, we'd get a lot of
// redundant complaints about the second definition
// location.)
break;
}
}
}
// We only call one_addr2line() in this function, so we can clear its cache.
Dwarf_line_info::clear_addr2line_cache();
}
// Warnings functions.
// Add a new warning.
void
Warnings::add_warning(Symbol_table* symtab, const char* name, Object* obj,
const std::string& warning)
{
name = symtab->canonicalize_name(name);
this->warnings_[name].set(obj, warning);
}
// Look through the warnings and mark the symbols for which we should
// warn. This is called during Layout::finalize when we know the
// sources for all the symbols.
void
Warnings::note_warnings(Symbol_table* symtab)
{
for (Warning_table::iterator p = this->warnings_.begin();
p != this->warnings_.end();
++p)
{
Symbol* sym = symtab->lookup(p->first, NULL);
if (sym != NULL
&& sym->source() == Symbol::FROM_OBJECT
&& sym->object() == p->second.object)
sym->set_has_warning();
}
}
// Issue a warning. This is called when we see a relocation against a
// symbol for which has a warning.
template<int size, bool big_endian>
void
Warnings::issue_warning(const Symbol* sym,
const Relocate_info<size, big_endian>* relinfo,
size_t relnum, off_t reloffset) const
{
gold_assert(sym->has_warning());
// We don't want to issue a warning for a relocation against the
// symbol in the same object file in which the symbol is defined.
if (sym->object() == relinfo->object)
return;
Warning_table::const_iterator p = this->warnings_.find(sym->name());
gold_assert(p != this->warnings_.end());
gold_warning_at_location(relinfo, relnum, reloffset,
"%s", p->second.text.c_str());
}
// Instantiate the templates we need. We could use the configure
// script to restrict this to only the ones needed for implemented
// targets.
#if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
template
void
Sized_symbol<32>::allocate_common(Output_data*, Value_type);
#endif
#if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
template
void
Sized_symbol<64>::allocate_common(Output_data*, Value_type);
#endif
#ifdef HAVE_TARGET_32_LITTLE
template
void
Symbol_table::add_from_relobj<32, false>(
Sized_relobj_file<32, false>* relobj,
const unsigned char* syms,
size_t count,
size_t symndx_offset,
const char* sym_names,
size_t sym_name_size,
Sized_relobj_file<32, false>::Symbols* sympointers,
size_t* defined);
#endif
#ifdef HAVE_TARGET_32_BIG
template
void
Symbol_table::add_from_relobj<32, true>(
Sized_relobj_file<32, true>* relobj,
const unsigned char* syms,
size_t count,
size_t symndx_offset,
const char* sym_names,
size_t sym_name_size,
Sized_relobj_file<32, true>::Symbols* sympointers,
size_t* defined);
#endif
#ifdef HAVE_TARGET_64_LITTLE
template
void
Symbol_table::add_from_relobj<64, false>(
Sized_relobj_file<64, false>* relobj,
const unsigned char* syms,
size_t count,
size_t symndx_offset,
const char* sym_names,
size_t sym_name_size,
Sized_relobj_file<64, false>::Symbols* sympointers,
size_t* defined);
#endif
#ifdef HAVE_TARGET_64_BIG
template
void
Symbol_table::add_from_relobj<64, true>(
Sized_relobj_file<64, true>* relobj,
const unsigned char* syms,
size_t count,
size_t symndx_offset,
const char* sym_names,
size_t sym_name_size,
Sized_relobj_file<64, true>::Symbols* sympointers,
size_t* defined);
#endif
#ifdef HAVE_TARGET_32_LITTLE
template
Symbol*
Symbol_table::add_from_pluginobj<32, false>(
Sized_pluginobj<32, false>* obj,
const char* name,
const char* ver,
elfcpp::Sym<32, false>* sym);
#endif
#ifdef HAVE_TARGET_32_BIG
template
Symbol*
Symbol_table::add_from_pluginobj<32, true>(
Sized_pluginobj<32, true>* obj,
const char* name,
const char* ver,
elfcpp::Sym<32, true>* sym);
#endif
#ifdef HAVE_TARGET_64_LITTLE
template
Symbol*
Symbol_table::add_from_pluginobj<64, false>(
Sized_pluginobj<64, false>* obj,
const char* name,
const char* ver,
elfcpp::Sym<64, false>* sym);
#endif
#ifdef HAVE_TARGET_64_BIG
template
Symbol*
Symbol_table::add_from_pluginobj<64, true>(
Sized_pluginobj<64, true>* obj,
const char* name,
const char* ver,
elfcpp::Sym<64, true>* sym);
#endif
#ifdef HAVE_TARGET_32_LITTLE
template
void
Symbol_table::add_from_dynobj<32, false>(
Sized_dynobj<32, false>* dynobj,
const unsigned char* syms,
size_t count,
const char* sym_names,
size_t sym_name_size,
const unsigned char* versym,
size_t versym_size,
const std::vector<const char*>* version_map,
Sized_relobj_file<32, false>::Symbols* sympointers,
size_t* defined);
#endif
#ifdef HAVE_TARGET_32_BIG
template
void
Symbol_table::add_from_dynobj<32, true>(
Sized_dynobj<32, true>* dynobj,
const unsigned char* syms,
size_t count,
const char* sym_names,
size_t sym_name_size,
const unsigned char* versym,
size_t versym_size,
const std::vector<const char*>* version_map,
Sized_relobj_file<32, true>::Symbols* sympointers,
size_t* defined);
#endif
#ifdef HAVE_TARGET_64_LITTLE
template
void
Symbol_table::add_from_dynobj<64, false>(
Sized_dynobj<64, false>* dynobj,
const unsigned char* syms,
size_t count,
const char* sym_names,
size_t sym_name_size,
const unsigned char* versym,
size_t versym_size,
const std::vector<const char*>* version_map,
Sized_relobj_file<64, false>::Symbols* sympointers,
size_t* defined);
#endif
#ifdef HAVE_TARGET_64_BIG
template
void
Symbol_table::add_from_dynobj<64, true>(
Sized_dynobj<64, true>* dynobj,
const unsigned char* syms,
size_t count,
const char* sym_names,
size_t sym_name_size,
const unsigned char* versym,
size_t versym_size,
const std::vector<const char*>* version_map,
Sized_relobj_file<64, true>::Symbols* sympointers,
size_t* defined);
#endif
#ifdef HAVE_TARGET_32_LITTLE
template
Sized_symbol<32>*
Symbol_table::add_from_incrobj(
Object* obj,
const char* name,
const char* ver,
elfcpp::Sym<32, false>* sym);
#endif
#ifdef HAVE_TARGET_32_BIG
template
Sized_symbol<32>*
Symbol_table::add_from_incrobj(
Object* obj,
const char* name,
const char* ver,
elfcpp::Sym<32, true>* sym);
#endif
#ifdef HAVE_TARGET_64_LITTLE
template
Sized_symbol<64>*
Symbol_table::add_from_incrobj(
Object* obj,
const char* name,
const char* ver,
elfcpp::Sym<64, false>* sym);
#endif
#ifdef HAVE_TARGET_64_BIG
template
Sized_symbol<64>*
Symbol_table::add_from_incrobj(
Object* obj,
const char* name,
const char* ver,
elfcpp::Sym<64, true>* sym);
#endif
#if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
template
void
Symbol_table::define_with_copy_reloc<32>(
Sized_symbol<32>* sym,
Output_data* posd,
elfcpp::Elf_types<32>::Elf_Addr value);
#endif
#if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
template
void
Symbol_table::define_with_copy_reloc<64>(
Sized_symbol<64>* sym,
Output_data* posd,
elfcpp::Elf_types<64>::Elf_Addr value);
#endif
#if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
template
void
Sized_symbol<32>::init_output_data(const char* name, const char* version,
Output_data* od, Value_type value,
Size_type symsize, elfcpp::STT type,
elfcpp::STB binding,
elfcpp::STV visibility,
unsigned char nonvis,
bool offset_is_from_end,
bool is_predefined);
template
void
Sized_symbol<32>::init_constant(const char* name, const char* version,
Value_type value, Size_type symsize,
elfcpp::STT type, elfcpp::STB binding,
elfcpp::STV visibility, unsigned char nonvis,
bool is_predefined);
template
void
Sized_symbol<32>::init_undefined(const char* name, const char* version,
Value_type value, elfcpp::STT type,
elfcpp::STB binding, elfcpp::STV visibility,
unsigned char nonvis);
#endif
#if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
template
void
Sized_symbol<64>::init_output_data(const char* name, const char* version,
Output_data* od, Value_type value,
Size_type symsize, elfcpp::STT type,
elfcpp::STB binding,
elfcpp::STV visibility,
unsigned char nonvis,
bool offset_is_from_end,
bool is_predefined);
template
void
Sized_symbol<64>::init_constant(const char* name, const char* version,
Value_type value, Size_type symsize,
elfcpp::STT type, elfcpp::STB binding,
elfcpp::STV visibility, unsigned char nonvis,
bool is_predefined);
template
void
Sized_symbol<64>::init_undefined(const char* name, const char* version,
Value_type value, elfcpp::STT type,
elfcpp::STB binding, elfcpp::STV visibility,
unsigned char nonvis);
#endif
#ifdef HAVE_TARGET_32_LITTLE
template
void
Warnings::issue_warning<32, false>(const Symbol* sym,
const Relocate_info<32, false>* relinfo,
size_t relnum, off_t reloffset) const;
#endif
#ifdef HAVE_TARGET_32_BIG
template
void
Warnings::issue_warning<32, true>(const Symbol* sym,
const Relocate_info<32, true>* relinfo,
size_t relnum, off_t reloffset) const;
#endif
#ifdef HAVE_TARGET_64_LITTLE
template
void
Warnings::issue_warning<64, false>(const Symbol* sym,
const Relocate_info<64, false>* relinfo,
size_t relnum, off_t reloffset) const;
#endif
#ifdef HAVE_TARGET_64_BIG
template
void
Warnings::issue_warning<64, true>(const Symbol* sym,
const Relocate_info<64, true>* relinfo,
size_t relnum, off_t reloffset) const;
#endif
} // End namespace gold.
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