// symtab.cc -- the gold symbol table
-// Copyright 2006, 2007, 2008 Free Software Foundation, Inc.
+// Copyright 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
// Written by Ian Lance Taylor <iant@google.com>.
// This file is part of gold.
#include <utility>
#include "demangle.h"
+#include "gc.h"
#include "object.h"
#include "dwarf_reader.h"
#include "dynobj.h"
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))
+ return false;
+ }
+
// If the symbol was forced local in a version script, do not add it.
if (this->is_forced_local())
return false;
const Version_script_info& version_script)
: saw_undefined_(0), offset_(0), table_(count), namepool_(),
forwarders_(), commons_(), tls_commons_(), forced_locals_(), warnings_(),
- version_script_(version_script)
+ version_script_(version_script), gc_(NULL)
{
namepool_.reserve(count);
}
return k1.first == k2.first && k1.second == k2.second;
}
+// For symbols that have been listed with -u option, add them to the
+// work list to avoid gc'ing them.
+
+void
+Symbol_table::gc_mark_undef_symbols()
+{
+ 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())
+ {
+ Relobj* obj = static_cast<Relobj*>(sym->object());
+ bool is_ordinary;
+ unsigned int shndx = sym->shndx(&is_ordinary);
+ if (is_ordinary)
+ {
+ gold_assert(this->gc_ != NULL);
+ this->gc_->worklist().push(Section_id(obj, shndx));
+ }
+ }
+ }
+}
+
+void
+Symbol_table::gc_mark_symbol_for_shlib(Symbol* sym)
+{
+ if (!sym->is_from_dynobj()
+ && sym->is_externally_visible())
+ {
+ //Add the object and section to the work list.
+ Relobj* obj = static_cast<Relobj*>(sym->object());
+ bool is_ordinary;
+ unsigned int shndx = sym->shndx(&is_ordinary);
+ if (is_ordinary && shndx != elfcpp::SHN_UNDEF)
+ {
+ gold_assert(this->gc_!= NULL);
+ this->gc_->worklist().push(Section_id(obj, shndx));
+ }
+ }
+}
+
+// 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())
+ {
+ Relobj *obj = static_cast<Relobj*>(sym->object());
+ bool is_ordinary;
+ unsigned int shndx = sym->shndx(&is_ordinary);
+ if (is_ordinary && shndx != elfcpp::SHN_UNDEF)
+ {
+ gold_assert(this->gc_ != NULL);
+ this->gc_->worklist().push(Section_id(obj, shndx));
+ }
+ }
+}
+
// Make TO a symbol which forwards to FROM.
void
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.
+// Record that a symbol is forced to be local by a version script or
+// by visibility.
void
Symbol_table::force_local(Symbol* sym)
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.
+
+ // 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
+ {
+ 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
this->resolve(ret, sym, st_shndx, is_ordinary, orig_st_shndx, object,
version);
+ if (parameters->options().gc_sections())
+ this->gc_mark_dyn_syms(ret);
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. 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.
-
- // Otherwise, we just resolve the symbols as though they
- // were the same.
-
- if (insdef.first->second->version() != NULL)
- {
- gold_assert(insdef.first->second->version() != version);
- def = false;
- }
- else if (ret->visibility() != elfcpp::STV_DEFAULT
- && insdef.first->second->is_from_dynobj())
- def = false;
- else if (insdef.first->second->visibility() != elfcpp::STV_DEFAULT
- && ret->is_from_dynobj())
- def = false;
- else
- {
- const Sized_symbol<size>* sym2;
- sym2 = this->get_sized_symbol<size>(insdef.first->second);
- Symbol_table::resolve<size, big_endian>(ret, sym2);
- this->make_forwarder(insdef.first->second, ret);
- insdef.first->second = ret;
- }
- }
- else
- def = false;
- }
+ this->define_default_version<size, big_endian>(ret, insdef.second,
+ insdef.first);
}
else
{
this->resolve(ret, sym, st_shndx, is_ordinary, orig_st_shndx, object,
version);
+ if (parameters->options().gc_sections())
+ this->gc_mark_dyn_syms(ret);
ins.first->second = ret;
}
else
insdef.first->second = ret;
}
}
+
+ if (def)
+ ret->set_is_default();
}
// Record every time we see a new undefined symbol, to speed up
this->tls_commons_.push_back(ret);
}
- if (def)
- ret->set_is_default();
+ // 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_WEAK)
+ && !parameters->options().relocatable())
+ this->force_local(ret);
+
return ret;
}
res = this->add_from_object(relobj, name, name_key, ver, ver_key,
def, *psym, st_shndx, is_ordinary,
orig_st_shndx);
+
+ // If building a shared library using garbage collection, do not
+ // treat externally visible symbols as garbage.
+ if (parameters->options().gc_sections()
+ && parameters->options().shared())
+ this->gc_mark_symbol_for_shlib(res);
if (local)
this->force_local(res);
def, *sym, st_shndx, true, st_shndx);
if (local)
- this->force_local(res);
+ this->force_local(res);
return res;
}
// 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 canonicalizes *PNAME and *PVERSION.
+// 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,
- Sized_symbol<size>** poldsym)
+ Sized_symbol<size>** poldsym,
+ bool *resolve_oldsym)
{
- Symbol* oldsym;
- Sized_symbol<size>* sym;
- bool add_to_table = false;
- typename Symbol_table_type::iterator add_loc = this->table_.end();
+ *resolve_oldsym = false;
// 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 (*pversion == NULL)
{
if (this->version_script_.get_symbol_version(*pname, &v))
{
if (!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 || !oldsym->is_undefined())
return NULL;
*pname = oldsym->name();
- *pversion = oldsym->version();
+ if (!is_default_version)
+ *pversion = oldsym->version();
}
else
{
version_key),
snull));
+ std::pair<typename Symbol_table_type::iterator, bool> insdef =
+ std::make_pair(this->table_.end(), false);
+ if (is_default_version)
+ {
+ const Stringpool::Key vnull = 0;
+ insdef = 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,
+ insdef.second,
+ insdef.first);
+ }
}
else
{
// We haven't seen this symbol before.
gold_assert(ins.first->second == NULL);
- add_to_table = true;
- add_loc = ins.first;
- oldsym = NULL;
+
+ add_to_table = true;
+ add_loc = ins.first;
+
+ if (is_default_version && !insdef.second)
+ {
+ // We are adding NAME/VERSION, and it is the default
+ // version. We already have an entry for NAME/NULL.
+ oldsym = insdef.first->second;
+ *resolve_oldsym = true;
+ }
+ else
+ {
+ oldsym = NULL;
+
+ if (is_default_version)
+ {
+ add_def_to_table = true;
+ add_def_loc = insdef.first;
+ }
+ }
}
}
else
gold_assert(oldsym != NULL);
+ if (add_def_to_table)
+ add_def_loc->second = sym;
+
*poldsym = this->get_sized_symbol<size>(oldsym);
return sym;
{
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,
- only_if_ref, &oldsym);
+ only_if_ref, &oldsym,
+ &resolve_oldsym);
#else
gold_unreachable();
#endif
{
#if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
sym = this->define_special_symbol<size, false>(&name, &version,
- only_if_ref, &oldsym);
+ only_if_ref, &oldsym,
+ &resolve_oldsym);
#else
gold_unreachable();
#endif
if (Symbol_table::should_override_with_special(oldsym))
this->override_with_special(oldsym, sym);
- delete sym;
- return oldsym;
+
+ if (resolve_oldsym)
+ return sym;
+ else
+ {
+ delete sym;
+ return oldsym;
+ }
}
// Define a symbol based on an Output_segment.
{
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,
- only_if_ref, &oldsym);
+ only_if_ref, &oldsym,
+ &resolve_oldsym);
#else
gold_unreachable();
#endif
{
#if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
sym = this->define_special_symbol<size, false>(&name, &version,
- only_if_ref, &oldsym);
+ only_if_ref, &oldsym,
+ &resolve_oldsym);
#else
gold_unreachable();
#endif
if (Symbol_table::should_override_with_special(oldsym))
this->override_with_special(oldsym, sym);
- delete sym;
- return oldsym;
+
+ if (resolve_oldsym)
+ return sym;
+ else
+ {
+ delete sym;
+ return oldsym;
+ }
}
// Define a special symbol with a constant value. It is a multiple
{
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,
- only_if_ref, &oldsym);
+ only_if_ref, &oldsym,
+ &resolve_oldsym);
#else
gold_unreachable();
#endif
{
#if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
sym = this->define_special_symbol<size, false>(&name, &version,
- only_if_ref, &oldsym);
+ only_if_ref, &oldsym,
+ &resolve_oldsym);
#else
gold_unreachable();
#endif
if (force_override || Symbol_table::should_override_with_special(oldsym))
this->override_with_special(oldsym, sym);
- delete sym;
- return oldsym;
+
+ if (resolve_oldsym)
+ return sym;
+ else
+ {
+ delete sym;
+ return oldsym;
+ }
}
// Define a set of symbols in output sections.
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, &oldsym);
+ false, &oldsym,
+ &resolve_oldsym);
#else
gold_unreachable();
#endif
{
#if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
sym = this->define_special_symbol<size, false>(&name, &version,
- false, &oldsym);
+ false, &oldsym,
+ &resolve_oldsym);
#else
gold_unreachable();
#endif
if (os == NULL)
{
sym->set_symtab_index(-1U);
- gold_assert(sym->dynsym_index() == -1U);
+ bool static_or_reloc = (parameters->doing_static_link() ||
+ parameters->options().relocatable());
+ gold_assert(static_or_reloc || sym->dynsym_index() == -1U);
+
return false;
}
// Write out the global symbols.
void
-Symbol_table::write_globals(const Input_objects* input_objects,
- const Stringpool* sympool,
+Symbol_table::write_globals(const Stringpool* sympool,
const Stringpool* dynpool,
Output_symtab_xindex* symtab_xindex,
Output_symtab_xindex* dynsym_xindex,
{
#ifdef HAVE_TARGET_32_LITTLE
case Parameters::TARGET_32_LITTLE:
- this->sized_write_globals<32, false>(input_objects, sympool,
- dynpool, symtab_xindex,
+ 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>(input_objects, sympool,
- dynpool, symtab_xindex,
+ 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>(input_objects, sympool,
- dynpool, symtab_xindex,
+ 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>(input_objects, sympool,
- dynpool, symtab_xindex,
+ this->sized_write_globals<64, true>(sympool, dynpool, symtab_xindex,
dynsym_xindex, of);
break;
#endif
template<int size, bool big_endian>
void
-Symbol_table::sized_write_globals(const Input_objects* input_objects,
- const Stringpool* sympool,
+Symbol_table::sized_write_globals(const Stringpool* sympool,
const Stringpool* dynpool,
Output_symtab_xindex* symtab_xindex,
Output_symtab_xindex* dynsym_xindex,
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(input_objects, sym);
+ this->warn_about_undefined_dynobj_symbol(sym);
unsigned int sym_index = sym->symtab_index();
unsigned int dynsym_index;
// 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 the system library
-// directory (the directory were we find libc.so); we assume that
-// those libraries are OK. This heuristic avoids problems in
-// GNU/Linux, in which -ldl can have undefined references satisfied by
-// ld-linux.so.
+// 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(
- const Input_objects* input_objects,
- Symbol* sym) const
+Symbol_table::warn_about_undefined_dynobj_symbol(Symbol* sym) const
{
bool dummy;
if (sym->source() == Symbol::FROM_OBJECT
&& sym->binding() != elfcpp::STB_WEAK
&& !parameters->options().allow_shlib_undefined()
&& !parameters->target().is_defined_by_abi(sym)
- && !input_objects->found_in_system_library_directory(sym->object()))
+ && !sym->object()->is_in_system_directory())
{
// A very ugly cast.
Dynobj* dynobj = static_cast<Dynobj*>(sym->object());
if (!dynobj->has_unknown_needed_entries())
- {
- if (sym->version())
- gold_error(_("%s: undefined reference to '%s', version '%s'"),
- sym->object()->name().c_str(),
- sym->demangled_name().c_str(),
- sym->version());
- else
- gold_error(_("%s: undefined reference to '%s'"),
- sym->object()->name().c_str(),
- sym->demangled_name().c_str());
- }
+ gold_undefined_symbol(sym);
}
}
elfcpp::Sym_write<size, big_endian> osym(pov);
osym.put_st_name(0);
- osym.put_st_value(os->address());
+ 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));
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