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binutils-gdb/gold/symtab.cc

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// symtab.cc -- the gold symbol table
#include "gold.h"
#include <stdint.h>
#include <string>
#include <utility>
#include "object.h"
#include "dynobj.h"
#include "output.h"
#include "target.h"
#include "workqueue.h"
#include "symtab.h"
namespace gold
{
// Class Symbol.
// Initialize fields in Symbol. This initializes everything except u_
// 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_offset_ = 0;
this->type_ = type;
this->binding_ = binding;
this->visibility_ = visibility;
this->nonvis_ = nonvis;
this->is_target_special_ = false;
this->is_def_ = false;
this->is_forwarder_ = false;
this->needs_dynsym_entry_ = false;
this->in_reg_ = false;
this->in_dyn_ = false;
this->has_got_offset_ = false;
this->has_warning_ = false;
}
// Initialize the fields in the base class Symbol for SYM in OBJECT.
template<int size, bool big_endian>
void
Symbol::init_base(const char* name, const char* version, Object* object,
const elfcpp::Sym<size, big_endian>& sym)
{
this->init_fields(name, version, sym.get_st_type(), sym.get_st_bind(),
sym.get_st_visibility(), sym.get_st_nonvis());
this->u_.from_object.object = object;
// FIXME: Handle SHN_XINDEX.
this->u_.from_object.shndx = sym.get_st_shndx();
this->source_ = FROM_OBJECT;
this->in_reg_ = !object->is_dynamic();
this->in_dyn_ = object->is_dynamic();
}
// Initialize the fields in the base class Symbol for a symbol defined
// in an Output_data.
void
Symbol::init_base(const char* name, Output_data* od, elfcpp::STT type,
elfcpp::STB binding, elfcpp::STV visibility,
unsigned char nonvis, bool offset_is_from_end)
{
this->init_fields(name, NULL, type, binding, visibility, nonvis);
this->u_.in_output_data.output_data = od;
this->u_.in_output_data.offset_is_from_end = offset_is_from_end;
this->source_ = IN_OUTPUT_DATA;
this->in_reg_ = true;
}
// Initialize the fields in the base class Symbol for a symbol defined
// in an Output_segment.
void
Symbol::init_base(const char* name, Output_segment* os, elfcpp::STT type,
elfcpp::STB binding, elfcpp::STV visibility,
unsigned char nonvis, Segment_offset_base offset_base)
{
this->init_fields(name, NULL, type, binding, visibility, nonvis);
this->u_.in_output_segment.output_segment = os;
this->u_.in_output_segment.offset_base = offset_base;
this->source_ = IN_OUTPUT_SEGMENT;
this->in_reg_ = true;
}
// Initialize the fields in the base class Symbol for a symbol defined
// as a constant.
void
Symbol::init_base(const char* name, elfcpp::STT type,
elfcpp::STB binding, elfcpp::STV visibility,
unsigned char nonvis)
{
this->init_fields(name, NULL, type, binding, visibility, nonvis);
this->source_ = CONSTANT;
this->in_reg_ = true;
}
// Initialize the fields in Sized_symbol for SYM in OBJECT.
template<int size>
template<bool big_endian>
void
Sized_symbol<size>::init(const char* name, const char* version, Object* object,
const elfcpp::Sym<size, big_endian>& sym)
{
this->init_base(name, version, object, sym);
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(const char* name, 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)
{
this->init_base(name, od, type, binding, visibility, nonvis,
offset_is_from_end);
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(const char* name, 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)
{
this->init_base(name, os, type, binding, visibility, nonvis, offset_base);
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(const char* name, Value_type value, Size_type symsize,
elfcpp::STT type, elfcpp::STB binding,
elfcpp::STV visibility, unsigned char nonvis)
{
this->init_base(name, type, binding, visibility, nonvis);
this->value_ = value;
this->symsize_ = symsize;
}
// Class Symbol_table.
Symbol_table::Symbol_table()
: size_(0), saw_undefined_(0), offset_(0), table_(), namepool_(),
forwarders_(), commons_(), warnings_()
{
}
Symbol_table::~Symbol_table()
{
}
// The hash function. The key is always canonicalized, so we use a
// simple combination of the pointers.
size_t
Symbol_table::Symbol_table_hash::operator()(const Symbol_table_key& key) const
{
return key.first ^ key.second;
}
// The symbol table key equality function. This is only called with
// canonicalized name and version strings, so we can use pointer
// comparison.
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;
}
// 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,
const char* version ACCEPT_SIZE_ENDIAN)
{
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 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());
esym.put_st_shndx(from->shndx());
Symbol_table::resolve(to, esym.sym(), from->object(), version);
}
// 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.
// If DEF 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.
template<int size, bool big_endian>
Symbol*
Symbol_table::add_from_object(Object* object,
const char *name,
Stringpool::Key name_key,
const char *version,
Stringpool::Key version_key,
bool def,
const elfcpp::Sym<size, big_endian>& sym)
{
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> insdef =
std::make_pair(this->table_.end(), false);
if (def)
{
const Stringpool::Key vnull_key = 0;
insdef = 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;
bool was_undefined;
bool was_common;
if (!ins.second)
{
// We already have an entry for NAME/VERSION.
ret = this->get_sized_symbol SELECT_SIZE_NAME(size) (ins.first->second
SELECT_SIZE(size));
gold_assert(ret != NULL);
was_undefined = ret->is_undefined();
was_common = ret->is_common();
Symbol_table::resolve(ret, sym, object, version);
if (def)
{
if (insdef.second)
{
// This is the first time we have seen NAME/NULL. Make
// NAME/NULL point to NAME/VERSION.
insdef.first->second = ret;
}
else if (insdef.first->second != ret)
{
// This is the unfortunate case where we already have
// entries for both NAME/VERSION and NAME/NULL.
const Sized_symbol<size>* sym2;
sym2 = this->get_sized_symbol SELECT_SIZE_NAME(size) (
insdef.first->second
SELECT_SIZE(size));
Symbol_table::resolve SELECT_SIZE_ENDIAN_NAME(size, big_endian) (
ret, sym2, version SELECT_SIZE_ENDIAN(size, big_endian));
this->make_forwarder(insdef.first->second, ret);
insdef.first->second = ret;
}
}
}
else
{
// This is the first time we have seen NAME/VERSION.
gold_assert(ins.first->second == NULL);
was_undefined = false;
was_common = false;
if (def && !insdef.second)
{
// We already have an entry for NAME/NULL. If we override
// it, then change it to NAME/VERSION.
ret = this->get_sized_symbol SELECT_SIZE_NAME(size) (
insdef.first->second
SELECT_SIZE(size));
Symbol_table::resolve(ret, sym, object, version);
ins.first->second = ret;
}
else
{
Sized_target<size, big_endian>* target =
object->sized_target SELECT_SIZE_ENDIAN_NAME(size, big_endian) (
SELECT_SIZE_ENDIAN_ONLY(size, big_endian));
if (!target->has_make_symbol())
ret = new Sized_symbol<size>();
else
{
ret = target->make_symbol();
if (ret == NULL)
{
// This means that we don't want a symbol table
// entry after all.
if (!def)
this->table_.erase(ins.first);
else
{
this->table_.erase(insdef.first);
// Inserting insdef invalidated ins.
this->table_.erase(std::make_pair(name_key,
version_key));
}
return NULL;
}
}
ret->init(name, version, object, sym);
ins.first->second = ret;
if (def)
{
// This is the first time we have seen NAME/NULL. Point
// it at the new entry for NAME/VERSION.
gold_assert(insdef.second);
insdef.first->second = ret;
}
}
}
// Record every time we see a new undefined symbol, to speed up
// archive groups.
if (!was_undefined && ret->is_undefined())
++this->saw_undefined_;
// Keep track of common symbols, to speed up common symbol
// allocation.
if (!was_common && ret->is_common())
this->commons_.push_back(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<size, big_endian>* relobj,
const unsigned char* syms,
size_t count,
const char* sym_names,
size_t sym_name_size,
Symbol** sympointers)
{
// We take the size from the first object we see.
if (this->get_size() == 0)
this->set_size(size);
if (size != this->get_size() || size != relobj->target()->get_size())
{
fprintf(stderr, _("%s: %s: mixing 32-bit and 64-bit ELF objects\n"),
program_name, relobj->name().c_str());
gold_exit(false);
}
const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
const unsigned char* p = syms;
for (size_t i = 0; i < count; ++i, p += sym_size)
{
elfcpp::Sym<size, big_endian> sym(p);
elfcpp::Sym<size, big_endian>* psym = &sym;
unsigned int st_name = psym->get_st_name();
if (st_name >= sym_name_size)
{
fprintf(stderr,
_("%s: %s: bad global symbol name offset %u at %lu\n"),
program_name, relobj->name().c_str(), st_name,
static_cast<unsigned long>(i));
gold_exit(false);
}
const char* name = sym_names + st_name;
// A symbol defined in a section which we are not including must
// be treated as an undefined symbol.
unsigned char symbuf[sym_size];
elfcpp::Sym<size, big_endian> sym2(symbuf);
unsigned int st_shndx = psym->get_st_shndx();
if (st_shndx != elfcpp::SHN_UNDEF
&& st_shndx < elfcpp::SHN_LORESERVE
&& !relobj->is_section_included(st_shndx))
{
memcpy(symbuf, p, sym_size);
elfcpp::Sym_write<size, big_endian> sw(symbuf);
sw.put_st_shndx(elfcpp::SHN_UNDEF);
psym = &sym2;
}
// 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, '@');
Symbol* res;
if (ver == NULL)
{
Stringpool::Key name_key;
name = this->namepool_.add(name, &name_key);
res = this->add_from_object(relobj, name, name_key, NULL, 0,
false, *psym);
}
else
{
Stringpool::Key name_key;
name = this->namepool_.add(name, ver - name, &name_key);
bool def = false;
++ver;
if (*ver == '@')
{
def = true;
++ver;
}
Stringpool::Key ver_key;
ver = this->namepool_.add(ver, &ver_key);
res = this->add_from_object(relobj, name, name_key, ver, ver_key,
def, *psym);
}
*sympointers++ = 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)
{
// We take the size from the first object we see.
if (this->get_size() == 0)
this->set_size(size);
if (size != this->get_size() || size != dynobj->target()->get_size())
{
fprintf(stderr, _("%s: %s: mixing 32-bit and 64-bit ELF objects\n"),
program_name, dynobj->name().c_str());
gold_exit(false);
}
if (versym != NULL && versym_size / 2 < count)
{
fprintf(stderr, _("%s: %s: too few symbol versions\n"),
program_name, dynobj->name().c_str());
gold_exit(false);
}
const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
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);
// Ignore symbols with local binding.
if (sym.get_st_bind() == elfcpp::STB_LOCAL)
continue;
unsigned int st_name = sym.get_st_name();
if (st_name >= sym_name_size)
{
fprintf(stderr, _("%s: %s: bad symbol name offset %u at %lu\n"),
program_name, dynobj->name().c_str(), st_name,
static_cast<unsigned long>(i));
gold_exit(false);
}
const char* name = sym_names + st_name;
if (versym == NULL)
{
Stringpool::Key name_key;
name = this->namepool_.add(name, &name_key);
this->add_from_object(dynobj, name, name_key, NULL, 0,
false, sym);
continue;
}
// 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;
if (v == static_cast<unsigned int>(elfcpp::VER_NDX_LOCAL))
{
// 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, &name_key);
if (v == static_cast<unsigned int>(elfcpp::VER_NDX_GLOBAL))
{
// This symbol does not have a version.
this->add_from_object(dynobj, name, name_key, NULL, 0, false, sym);
continue;
}
if (v >= version_map->size())
{
fprintf(stderr,
_("%s: %s: versym for symbol %zu out of range: %u\n"),
program_name, dynobj->name().c_str(), i, v);
gold_exit(false);
}
const char* version = (*version_map)[v];
if (version == NULL)
{
fprintf(stderr, _("%s: %s: versym for symbol %zu has no name: %u\n"),
program_name, dynobj->name().c_str(), i, v);
gold_exit(false);
}
Stringpool::Key version_key;
version = this->namepool_.add(version, &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 (sym.get_st_shndx() == elfcpp::SHN_ABS && name_key == version_key)
{
this->add_from_object(dynobj, name, name_key, NULL, 0, false, sym);
continue;
}
const bool def = !hidden && sym.get_st_shndx() != elfcpp::SHN_UNDEF;
this->add_from_object(dynobj, name, name_key, version, version_key,
def, sym);
}
}
// 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.
template<int size, bool big_endian>
Sized_symbol<size>*
Symbol_table::define_special_symbol(const Target* target, const char* name,
const char* version, bool only_if_ref
ACCEPT_SIZE_ENDIAN)
{
gold_assert(this->size_ == size);
Symbol* oldsym;
Sized_symbol<size>* sym;
if (only_if_ref)
{
oldsym = this->lookup(name, version);
if (oldsym == NULL || !oldsym->is_undefined())
return NULL;
sym = NULL;
// Canonicalize NAME and VERSION.
name = oldsym->name();
version = oldsym->version();
}
else
{
// Canonicalize NAME and VERSION.
Stringpool::Key name_key;
name = this->namepool_.add(name, &name_key);
Stringpool::Key version_key = 0;
if (version != NULL)
version = this->namepool_.add(version, &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));
if (!ins.second)
{
// We already have a symbol table entry for NAME/VERSION.
oldsym = ins.first->second;
gold_assert(oldsym != NULL);
sym = NULL;
}
else
{
// We haven't seen this symbol before.
gold_assert(ins.first->second == NULL);
if (!target->has_make_symbol())
sym = new Sized_symbol<size>();
else
{
gold_assert(target->get_size() == size);
gold_assert(target->is_big_endian() ? big_endian : !big_endian);
typedef Sized_target<size, big_endian> My_target;
const My_target* sized_target =
static_cast<const My_target*>(target);
sym = sized_target->make_symbol();
if (sym == NULL)
return NULL;
}
ins.first->second = sym;
oldsym = NULL;
}
}
if (oldsym != NULL)
{
gold_assert(sym == NULL);
sym = this->get_sized_symbol SELECT_SIZE_NAME(size) (oldsym
SELECT_SIZE(size));
gold_assert(sym->source() == Symbol::FROM_OBJECT);
const int old_shndx = sym->shndx();
if (old_shndx != elfcpp::SHN_UNDEF
&& old_shndx != elfcpp::SHN_COMMON
&& !sym->object()->is_dynamic())
{
fprintf(stderr, "%s: linker defined: multiple definition of %s\n",
program_name, name);
// FIXME: Report old location. Record that we have seen an
// error.
return NULL;
}
// Our new definition is going to override the old reference.
}
return sym;
}
// Define a symbol based on an Output_data.
Symbol*
Symbol_table::define_in_output_data(const Target* target, const char* name,
const char* version, 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)
{
gold_assert(target->get_size() == this->size_);
if (this->size_ == 32)
return this->do_define_in_output_data<32>(target, name, version, od, value,
symsize, type, binding,
visibility, nonvis,
offset_is_from_end, only_if_ref);
else if (this->size_ == 64)
return this->do_define_in_output_data<64>(target, name, version, od, value,
symsize, type, binding,
visibility, nonvis,
offset_is_from_end, only_if_ref);
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 Target* target,
const char* name,
const char* version,
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;
if (target->is_big_endian())
sym = this->define_special_symbol SELECT_SIZE_ENDIAN_NAME(size, true) (
target, name, version, only_if_ref
SELECT_SIZE_ENDIAN(size, true));
else
sym = this->define_special_symbol SELECT_SIZE_ENDIAN_NAME(size, false) (
target, name, version, only_if_ref
SELECT_SIZE_ENDIAN(size, false));
if (sym == NULL)
return NULL;
sym->init(name, od, value, symsize, type, binding, visibility, nonvis,
offset_is_from_end);
return sym;
}
// Define a symbol based on an Output_segment.
Symbol*
Symbol_table::define_in_output_segment(const Target* target, const char* name,
const char* version, 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)
{
gold_assert(target->get_size() == this->size_);
if (this->size_ == 32)
return this->do_define_in_output_segment<32>(target, name, version, os,
value, symsize, type, binding,
visibility, nonvis,
offset_base, only_if_ref);
else if (this->size_ == 64)
return this->do_define_in_output_segment<64>(target, name, version, os,
value, symsize, type, binding,
visibility, nonvis,
offset_base, only_if_ref);
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 Target* target,
const char* name,
const char* version,
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;
if (target->is_big_endian())
sym = this->define_special_symbol SELECT_SIZE_ENDIAN_NAME(size, true) (
target, name, version, only_if_ref
SELECT_SIZE_ENDIAN(size, true));
else
sym = this->define_special_symbol SELECT_SIZE_ENDIAN_NAME(size, false) (
target, name, version, only_if_ref
SELECT_SIZE_ENDIAN(size, false));
if (sym == NULL)
return NULL;
sym->init(name, os, value, symsize, type, binding, visibility, nonvis,
offset_base);
return sym;
}
// 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 Target* target, const char* name,
const char* version, uint64_t value,
uint64_t symsize, elfcpp::STT type,
elfcpp::STB binding, elfcpp::STV visibility,
unsigned char nonvis, bool only_if_ref)
{
gold_assert(target->get_size() == this->size_);
if (this->size_ == 32)
return this->do_define_as_constant<32>(target, name, version, value,
symsize, type, binding, visibility,
nonvis, only_if_ref);
else if (this->size_ == 64)
return this->do_define_as_constant<64>(target, name, version, value,
symsize, type, binding, visibility,
nonvis, only_if_ref);
else
gold_unreachable();
}
// Define a symbol as a constant, sized version.
template<int size>
Sized_symbol<size>*
Symbol_table::do_define_as_constant(
const Target* target,
const char* name,
const char* version,
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)
{
Sized_symbol<size>* sym;
if (target->is_big_endian())
sym = this->define_special_symbol SELECT_SIZE_ENDIAN_NAME(size, true) (
target, name, version, only_if_ref
SELECT_SIZE_ENDIAN(size, true));
else
sym = this->define_special_symbol SELECT_SIZE_ENDIAN_NAME(size, false) (
target, name, version, only_if_ref
SELECT_SIZE_ENDIAN(size, false));
if (sym == NULL)
return NULL;
sym->init(name, value, symsize, type, binding, visibility, nonvis);
return sym;
}
// Define a set of symbols in output sections.
void
Symbol_table::define_symbols(const Layout* layout, const Target* target,
int count, const Define_symbol_in_section* p)
{
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(target, p->name, NULL, os, p->value,
p->size, p->type, p->binding,
p->visibility, p->nonvis,
p->offset_is_from_end, p->only_if_ref);
else
this->define_as_constant(target, p->name, NULL, 0, p->size, p->type,
p->binding, p->visibility, p->nonvis,
p->only_if_ref);
}
}
// Define a set of symbols in output segments.
void
Symbol_table::define_symbols(const Layout* layout, const Target* target,
int count, const Define_symbol_in_segment* p)
{
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(target, p->name, NULL, os, p->value,
p->size, p->type, p->binding,
p->visibility, p->nonvis,
p->offset_base, p->only_if_ref);
else
this->define_as_constant(target, p->name, NULL, 0, p->size, p->type,
p->binding, p->visibility, p->nonvis,
p->only_if_ref);
}
}
// Set the dynamic symbol indexes. INDEX is the index of the first
// global dynamic symbol. Pointers to the 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(const General_options* options,
const Target* target,
unsigned int index,
std::vector<Symbol*>* syms,
Stringpool* dynpool,
Versions* versions)
{
for (Symbol_table_type::iterator p = this->table_.begin();
p != this->table_.end();
++p)
{
Symbol* sym = p->second;
// 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->needs_dynsym_entry())
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(), NULL);
// Record any version information.
if (sym->version() != NULL)
versions->record_version(options, dynpool, sym);
}
}
// Finish up the versions. In some cases this may add new dynamic
// symbols.
index = versions->finalize(target, this, index, syms);
return index;
}
// Set the final values for all the symbols. The index of the first
// global symbol in the output file is INDEX. Record the file offset
// OFF. Add their names to POOL. Return the new file offset.
off_t
Symbol_table::finalize(unsigned int index, off_t off, off_t dynoff,
size_t dyn_global_index, size_t dyncount,
Stringpool* pool)
{
off_t ret;
gold_assert(index != 0);
this->first_global_index_ = index;
this->dynamic_offset_ = dynoff;
this->first_dynamic_global_index_ = dyn_global_index;
this->dynamic_count_ = dyncount;
if (this->size_ == 32)
ret = this->sized_finalize<32>(index, off, pool);
else if (this->size_ == 64)
ret = this->sized_finalize<64>(index, off, pool);
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;
}
// 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(unsigned index, off_t off, Stringpool* pool)
{
off = align_address(off, size >> 3);
this->offset_ = off;
size_t orig_index = index;
const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
for (Symbol_table_type::iterator p = this->table_.begin();
p != this->table_.end();
++p)
{
Sized_symbol<size>* sym = static_cast<Sized_symbol<size>*>(p->second);
// FIXME: Here we need to decide which symbols should go into
// the output file, based on --strip.
// 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())
continue;
if (!sym->in_reg())
{
gold_assert(!sym->has_symtab_index());
sym->set_symtab_index(-1U);
gold_assert(sym->dynsym_index() == -1U);
continue;
}
typename Sized_symbol<size>::Value_type value;
switch (sym->source())
{
case Symbol::FROM_OBJECT:
{
unsigned int shndx = sym->shndx();
// FIXME: We need some target specific support here.
if (shndx >= elfcpp::SHN_LORESERVE
&& shndx != elfcpp::SHN_ABS)
{
fprintf(stderr, _("%s: %s: unsupported symbol section 0x%x\n"),
program_name, sym->name(), shndx);
gold_exit(false);
}
Object* symobj = sym->object();
if (symobj->is_dynamic())
{
value = 0;
shndx = elfcpp::SHN_UNDEF;
}
else if (shndx == elfcpp::SHN_UNDEF)
value = 0;
else if (shndx == elfcpp::SHN_ABS)
value = sym->value();
else
{
Relobj* relobj = static_cast<Relobj*>(symobj);
off_t secoff;
Output_section* os = relobj->output_section(shndx, &secoff);
if (os == NULL)
{
sym->set_symtab_index(-1U);
gold_assert(sym->dynsym_index() == -1U);
continue;
}
value = sym->value() + os->address() + secoff;
}
}
break;
case Symbol::IN_OUTPUT_DATA:
{
Output_data* od = sym->output_data();
value = sym->value() + od->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() + 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::CONSTANT:
value = sym->value();
break;
default:
gold_unreachable();
}
sym->set_value(value);
sym->set_symtab_index(index);
pool->add(sym->name(), NULL);
++index;
off += sym_size;
}
this->output_count_ = index - orig_index;
return off;
}
// Write out the global symbols.
void
Symbol_table::write_globals(const Target* target, const Stringpool* sympool,
const Stringpool* dynpool, Output_file* of) const
{
if (this->size_ == 32)
{
if (target->is_big_endian())
this->sized_write_globals<32, true>(target, sympool, dynpool, of);
else
this->sized_write_globals<32, false>(target, sympool, dynpool, of);
}
else if (this->size_ == 64)
{
if (target->is_big_endian())
this->sized_write_globals<64, true>(target, sympool, dynpool, of);
else
this->sized_write_globals<64, false>(target, sympool, dynpool, of);
}
else
gold_unreachable();
}
// Write out the global symbols.
template<int size, bool big_endian>
void
Symbol_table::sized_write_globals(const Target*,
const Stringpool* sympool,
const Stringpool* dynpool,
Output_file* of) const
{
const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
unsigned int index = this->first_global_index_;
const off_t oview_size = this->output_count_ * sym_size;
unsigned char* const psyms = of->get_output_view(this->offset_, oview_size);
unsigned int dynamic_count = this->dynamic_count_;
off_t dynamic_size = dynamic_count * sym_size;
unsigned int first_dynamic_global_index = this->first_dynamic_global_index_;
unsigned char* dynamic_view;
if (this->dynamic_offset_ == 0)
dynamic_view = NULL;
else
dynamic_view = of->get_output_view(this->dynamic_offset_, dynamic_size);
unsigned char* ps = psyms;
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);
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;
}
if (sym_index == index)
++index;
else if (sym_index != -1U)
{
// We have already seen this symbol, because it has a
// default version.
gold_assert(sym_index < index);
if (dynsym_index == -1U)
continue;
sym_index = -1U;
}
unsigned int shndx;
switch (sym->source())
{
case Symbol::FROM_OBJECT:
{
unsigned int in_shndx = sym->shndx();
// FIXME: We need some target specific support here.
if (in_shndx >= elfcpp::SHN_LORESERVE
&& in_shndx != elfcpp::SHN_ABS)
{
fprintf(stderr, _("%s: %s: unsupported symbol section 0x%x\n"),
program_name, sym->name(), in_shndx);
gold_exit(false);
}
Object* symobj = sym->object();
if (symobj->is_dynamic())
{
// FIXME.
shndx = elfcpp::SHN_UNDEF;
}
else if (in_shndx == elfcpp::SHN_UNDEF
|| in_shndx == elfcpp::SHN_ABS)
shndx = in_shndx;
else
{
Relobj* relobj = static_cast<Relobj*>(symobj);
off_t secoff;
Output_section* os = relobj->output_section(in_shndx, &secoff);
gold_assert(os != NULL);
shndx = os->out_shndx();
}
}
break;
case Symbol::IN_OUTPUT_DATA:
shndx = sym->output_data()->out_shndx();
break;
case Symbol::IN_OUTPUT_SEGMENT:
shndx = elfcpp::SHN_ABS;
break;
case Symbol::CONSTANT:
shndx = elfcpp::SHN_ABS;
break;
default:
gold_unreachable();
}
if (sym_index != -1U)
{
this->sized_write_symbol SELECT_SIZE_ENDIAN_NAME(size, big_endian) (
sym, shndx, sympool, ps
SELECT_SIZE_ENDIAN(size, big_endian));
ps += sym_size;
}
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 SELECT_SIZE_ENDIAN_NAME(size, big_endian) (
sym, shndx, dynpool, pd
SELECT_SIZE_ENDIAN(size, big_endian));
}
}
gold_assert(ps - psyms == oview_size);
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,
unsigned int shndx,
const Stringpool* pool,
unsigned char* p
ACCEPT_SIZE_ENDIAN) const
{
elfcpp::Sym_write<size, big_endian> osym(p);
osym.put_st_name(pool->get_offset(sym->name()));
osym.put_st_value(sym->value());
osym.put_st_size(sym->symsize());
osym.put_st_info(elfcpp::elf_st_info(sym->binding(), sym->type()));
osym.put_st_other(elfcpp::elf_st_other(sym->visibility(), sym->nonvis()));
osym.put_st_shndx(shndx);
}
// Write out a section symbol. Return the update offset.
void
Symbol_table::write_section_symbol(const Target* target,
const Output_section *os,
Output_file* of,
off_t offset) const
{
if (this->size_ == 32)
{
if (target->is_big_endian())
this->sized_write_section_symbol<32, true>(os, of, offset);
else
this->sized_write_section_symbol<32, false>(os, of, offset);
}
else if (this->size_ == 64)
{
if (target->is_big_endian())
this->sized_write_section_symbol<64, true>(os, of, offset);
else
this->sized_write_section_symbol<64, false>(os, of, offset);
}
else
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_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);
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));
osym.put_st_shndx(os->out_shndx());
of->write_output_view(offset, sym_size, pov);
}
// Warnings functions.
// Add a new warning.
void
Warnings::add_warning(Symbol_table* symtab, const char* name, Object* obj,
unsigned int shndx)
{
name = symtab->canonicalize_name(name);
this->warnings_[name].set(obj, shndx);
}
// 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();
// Read the section contents to get the warning text. It
// would be nicer if we only did this if we have to actually
// issue a warning. Unfortunately, warnings are issued as
// we relocate sections. That means that we can not lock
// the object then, as we might try to issue the same
// warning multiple times simultaneously.
{
Task_locker_obj<Object> tl(*p->second.object);
const unsigned char* c;
off_t len;
c = p->second.object->section_contents(p->second.shndx, &len);
p->second.set_text(reinterpret_cast<const char*>(c), len);
}
}
}
}
// Issue a warning. This is called when we see a relocation against a
// symbol for which has a warning.
void
Warnings::issue_warning(const Symbol* sym, const std::string& location) const
{
gold_assert(sym->has_warning());
Warning_table::const_iterator p = this->warnings_.find(sym->name());
gold_assert(p != this->warnings_.end());
fprintf(stderr, _("%s: %s: warning: %s\n"), program_name, location.c_str(),
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.
template
void
Symbol_table::add_from_relobj<32, true>(
Sized_relobj<32, true>* relobj,
const unsigned char* syms,
size_t count,
const char* sym_names,
size_t sym_name_size,
Symbol** sympointers);
template
void
Symbol_table::add_from_relobj<32, false>(
Sized_relobj<32, false>* relobj,
const unsigned char* syms,
size_t count,
const char* sym_names,
size_t sym_name_size,
Symbol** sympointers);
template
void
Symbol_table::add_from_relobj<64, true>(
Sized_relobj<64, true>* relobj,
const unsigned char* syms,
size_t count,
const char* sym_names,
size_t sym_name_size,
Symbol** sympointers);
template
void
Symbol_table::add_from_relobj<64, false>(
Sized_relobj<64, false>* relobj,
const unsigned char* syms,
size_t count,
const char* sym_names,
size_t sym_name_size,
Symbol** sympointers);
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);
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);
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);
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);
} // End namespace gold.
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