// resolve.cc -- symbol resolution for gold
-// Copyright 2006, 2007 Free Software Foundation, Inc.
+// Copyright 2006, 2007, 2008 Free Software Foundation, Inc.
// Written by Ian Lance Taylor <iant@google.com>.
// This file is part of gold.
this->symsize_ = sym.get_st_size();
}
+// Override TOSYM with symbol FROMSYM, defined in OBJECT, with version
+// VERSION. This handles all aliases of TOSYM.
+
+template<int size, bool big_endian>
+void
+Symbol_table::override(Sized_symbol<size>* tosym,
+ const elfcpp::Sym<size, big_endian>& fromsym,
+ Object* object, const char* version)
+{
+ tosym->override(fromsym, object, version);
+ if (tosym->has_alias())
+ {
+ Symbol* sym = this->weak_aliases_[tosym];
+ gold_assert(sym != NULL);
+ Sized_symbol<size>* ssym;
+ ssym = this->get_sized_symbol SELECT_SIZE_NAME(size) (sym
+ SELECT_SIZE(size));
+ do
+ {
+ ssym->override(fromsym, object, version);
+ sym = this->weak_aliases_[ssym];
+ gold_assert(sym != NULL);
+ ssym = this->get_sized_symbol SELECT_SIZE_NAME(size) (
+ sym SELECT_SIZE(size));
+ }
+ while (ssym != tosym);
+ }
+}
+
// The resolve functions build a little code for each symbol.
// Bit 0: 0 for global, 1 for weak.
// Bit 1: 0 for regular object, 1 for shared object
static const unsigned int undef_flag = 1 << def_undef_or_common_shift;
static const unsigned int common_flag = 2 << def_undef_or_common_shift;
+// This convenience function combines all the flags based on facts
+// about the symbol.
+
+static unsigned int
+symbol_to_bits(elfcpp::STB binding, bool is_dynamic,
+ unsigned int shndx, elfcpp::STT type)
+{
+ unsigned int bits;
+
+ switch (binding)
+ {
+ case elfcpp::STB_GLOBAL:
+ bits = global_flag;
+ break;
+
+ case elfcpp::STB_WEAK:
+ bits = weak_flag;
+ break;
+
+ case elfcpp::STB_LOCAL:
+ // We should only see externally visible symbols in the symbol
+ // table.
+ gold_error(_("invalid STB_LOCAL symbol in external symbols"));
+ bits = global_flag;
+
+ default:
+ // Any target which wants to handle STB_LOOS, etc., needs to
+ // define a resolve method.
+ gold_error(_("unsupported symbol binding"));
+ bits = global_flag;
+ }
+
+ if (is_dynamic)
+ bits |= dynamic_flag;
+ else
+ bits |= regular_flag;
+
+ switch (shndx)
+ {
+ case elfcpp::SHN_UNDEF:
+ bits |= undef_flag;
+ break;
+
+ case elfcpp::SHN_COMMON:
+ bits |= common_flag;
+ break;
+
+ default:
+ if (type == elfcpp::STT_COMMON)
+ bits |= common_flag;
+ else
+ bits |= def_flag;
+ break;
+ }
+
+ return bits;
+}
+
// Resolve a symbol. This is called the second and subsequent times
-// we see a symbol. TO is the pre-existing symbol. SYM is the new
-// symbol, seen in OBJECT. VERSION of the version of SYM.
+// we see a symbol. TO is the pre-existing symbol. ORIG_SYM is the
+// new symbol, seen in OBJECT. SYM is almost always identical to
+// ORIG_SYM, but may be munged (for instance, if we determine the
+// symbol is in a to-be-discarded section, we'll set sym's shndx to
+// UNDEFINED). VERSION of the version of SYM.
template<int size, bool big_endian>
void
Symbol_table::resolve(Sized_symbol<size>* to,
const elfcpp::Sym<size, big_endian>& sym,
+ const elfcpp::Sym<size, big_endian>& orig_sym,
Object* object, const char* version)
{
if (object->target()->has_resolve())
to->set_in_dyn();
}
- unsigned int frombits;
- switch (sym.get_st_bind())
- {
- case elfcpp::STB_GLOBAL:
- frombits = global_flag;
- break;
-
- case elfcpp::STB_WEAK:
- frombits = weak_flag;
- break;
-
- case elfcpp::STB_LOCAL:
- fprintf(stderr,
- _("%s: %s: invalid STB_LOCAL symbol %s in external symbols\n"),
- program_name, object->name().c_str(), to->name());
- gold_exit(false);
-
- default:
- fprintf(stderr,
- _("%s: %s: unsupported symbol binding %d for symbol %s\n"),
- program_name, object->name().c_str(),
- static_cast<int>(sym.get_st_bind()), to->name());
- gold_exit(false);
- }
-
- if (!object->is_dynamic())
- frombits |= regular_flag;
- else
- frombits |= dynamic_flag;
-
- switch (sym.get_st_shndx())
- {
- case elfcpp::SHN_UNDEF:
- frombits |= undef_flag;
- break;
-
- case elfcpp::SHN_COMMON:
- frombits |= common_flag;
- break;
-
- default:
- if (sym.get_st_type() == elfcpp::STT_COMMON)
- frombits |= common_flag;
- else
- frombits |= def_flag;
- break;
- }
+ unsigned int frombits = symbol_to_bits(sym.get_st_bind(),
+ object->is_dynamic(),
+ sym.get_st_shndx(),
+ sym.get_st_type());
bool adjust_common_sizes;
- if (Symbol_table::should_override(to, frombits, &adjust_common_sizes))
+ if (Symbol_table::should_override(to, frombits, object,
+ &adjust_common_sizes))
{
typename Sized_symbol<size>::Size_type tosize = to->symsize();
- to->override(sym, object, version);
+ this->override(to, sym, object, version);
if (adjust_common_sizes && tosize > to->symsize())
to->set_symsize(tosize);
if (adjust_common_sizes && sym.get_st_size() > to->symsize())
to->set_symsize(sym.get_st_size());
}
+
+ // A new weak undefined reference, merging with an old weak
+ // reference, could be a One Definition Rule (ODR) violation --
+ // especially if the types or sizes of the references differ. We'll
+ // store such pairs and look them up later to make sure they
+ // actually refer to the same lines of code. (Note: not all ODR
+ // violations can be found this way, and not everything this finds
+ // is an ODR violation. But it's helpful to warn about.)
+ // We use orig_sym here because we want the symbol exactly as it
+ // appears in the object file, not munged via our future processing.
+ if (parameters->detect_odr_violations()
+ && orig_sym.get_st_bind() == elfcpp::STB_WEAK
+ && to->binding() == elfcpp::STB_WEAK
+ && orig_sym.get_st_shndx() != elfcpp::SHN_UNDEF
+ && to->shndx() != elfcpp::SHN_UNDEF
+ && orig_sym.get_st_size() != 0 // Ignore weird 0-sized symbols.
+ && to->symsize() != 0
+ && (orig_sym.get_st_type() != to->type()
+ || orig_sym.get_st_size() != to->symsize())
+ // C does not have a concept of ODR, so we only need to do this
+ // on C++ symbols. These have (mangled) names starting with _Z.
+ && to->name()[0] == '_' && to->name()[1] == 'Z')
+ {
+ Symbol_location fromloc
+ = { object, orig_sym.get_st_shndx(), orig_sym.get_st_value() };
+ Symbol_location toloc = { to->object(), to->shndx(), to->value() };
+ this->candidate_odr_violations_[to->name()].insert(fromloc);
+ this->candidate_odr_violations_[to->name()].insert(toloc);
+ }
}
// Handle the core of symbol resolution. This is called with the
bool
Symbol_table::should_override(const Symbol* to, unsigned int frombits,
- bool* adjust_common_sizes)
+ Object* object, bool* adjust_common_sizes)
{
*adjust_common_sizes = false;
unsigned int tobits;
- switch (to->binding())
- {
- case elfcpp::STB_GLOBAL:
- tobits = global_flag;
- break;
-
- case elfcpp::STB_WEAK:
- tobits = weak_flag;
- break;
-
- case elfcpp::STB_LOCAL:
- // We should only see externally visible symbols in the symbol
- // table.
- gold_unreachable();
-
- default:
- // Any target which wants to handle STB_LOOS, etc., needs to
- // define a resolve method.
- gold_unreachable();
- }
-
- if (to->source() == Symbol::FROM_OBJECT
- && to->object()->is_dynamic())
- tobits |= dynamic_flag;
+ if (to->source() == Symbol::FROM_OBJECT)
+ tobits = symbol_to_bits(to->binding(),
+ to->object()->is_dynamic(),
+ to->shndx(),
+ to->type());
else
- tobits |= regular_flag;
-
- switch (to->shndx())
- {
- case elfcpp::SHN_UNDEF:
- tobits |= undef_flag;
- break;
-
- case elfcpp::SHN_COMMON:
- tobits |= common_flag;
- break;
-
- default:
- if (to->type() == elfcpp::STT_COMMON)
- tobits |= common_flag;
- else
- tobits |= def_flag;
- break;
- }
+ tobits = symbol_to_bits(to->binding(), false, elfcpp::SHN_ABS,
+ to->type());
// FIXME: Warn if either but not both of TO and SYM are STT_TLS.
{
case DEF * 16 + DEF:
// Two definitions of the same symbol.
- fprintf(stderr, "%s: multiple definition of %s\n",
- program_name, to->name());
- // FIXME: Report locations. Record that we have seen an error.
+ // FIXME: Do a better job of reporting locations.
+ gold_error(_("%s: multiple definition of %s"),
+ object != NULL ? object->name().c_str() : _("command line"),
+ to->demangled_name().c_str());
+ gold_error(_("%s: previous definition here"),
+ (to->source() == Symbol::FROM_OBJECT
+ ? to->object()->name().c_str()
+ : _("command line")));
return false;
case WEAK_DEF * 16 + DEF:
{
bool adjust_common_sizes;
unsigned int frombits = global_flag | regular_flag | def_flag;
- bool ret = Symbol_table::should_override(to, frombits, &adjust_common_sizes);
+ bool ret = Symbol_table::should_override(to, frombits, NULL,
+ &adjust_common_sizes);
gold_assert(!adjust_common_sizes);
return ret;
}
void
Symbol::override_base_with_special(const Symbol* from)
{
+ gold_assert(this->name_ == from->name_ || this->has_alias());
+
this->source_ = from->source_;
switch (from->source_)
{
// Special symbols are always considered to be regular symbols.
this->in_reg_ = true;
+
+ if (from->needs_dynsym_entry_)
+ this->needs_dynsym_entry_ = true;
+ if (from->needs_dynsym_value_)
+ this->needs_dynsym_value_ = true;
+
+ // We shouldn't see these flags. If we do, we need to handle them
+ // somehow.
+ gold_assert(!from->is_target_special_ || this->is_target_special_);
+ gold_assert(!from->is_forwarder_);
+ gold_assert(!from->has_got_offset_);
+ gold_assert(!from->has_plt_offset_);
+ gold_assert(!from->has_warning_);
+ gold_assert(!from->is_copied_from_dynobj_);
}
// Override a symbol with a special symbol.
this->symsize_ = from->symsize_;
}
+// Override TOSYM with the special symbol FROMSYM. This handles all
+// aliases of TOSYM.
+
+template<int size>
+void
+Symbol_table::override_with_special(Sized_symbol<size>* tosym,
+ const Sized_symbol<size>* fromsym)
+{
+ tosym->override_with_special(fromsym);
+ if (tosym->has_alias())
+ {
+ Symbol* sym = this->weak_aliases_[tosym];
+ gold_assert(sym != NULL);
+ Sized_symbol<size>* ssym;
+ ssym = this->get_sized_symbol SELECT_SIZE_NAME(size) (sym
+ SELECT_SIZE(size));
+ do
+ {
+ ssym->override_with_special(fromsym);
+ sym = this->weak_aliases_[ssym];
+ gold_assert(sym != NULL);
+ ssym = this->get_sized_symbol SELECT_SIZE_NAME(size) (
+ sym SELECT_SIZE(size));
+ }
+ while (ssym != tosym);
+ }
+}
+
// Instantiate the templates we need. We could use the configure
// script to restrict this to only the ones needed for implemented
// targets.
Symbol_table::resolve<32, false>(
Sized_symbol<32>* to,
const elfcpp::Sym<32, false>& sym,
+ const elfcpp::Sym<32, false>& orig_sym,
Object* object,
const char* version);
#endif
Symbol_table::resolve<32, true>(
Sized_symbol<32>* to,
const elfcpp::Sym<32, true>& sym,
+ const elfcpp::Sym<32, true>& orig_sym,
Object* object,
const char* version);
#endif
Symbol_table::resolve<64, false>(
Sized_symbol<64>* to,
const elfcpp::Sym<64, false>& sym,
+ const elfcpp::Sym<64, false>& orig_sym,
Object* object,
const char* version);
#endif
Symbol_table::resolve<64, true>(
Sized_symbol<64>* to,
const elfcpp::Sym<64, true>& sym,
+ const elfcpp::Sym<64, true>& orig_sym,
Object* object,
const char* version);
#endif
#if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
template
void
-Sized_symbol<32>::override_with_special(const Sized_symbol<32>*);
+Symbol_table::override_with_special<32>(Sized_symbol<32>*,
+ const Sized_symbol<32>*);
#endif
#if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
template
void
-Sized_symbol<64>::override_with_special(const Sized_symbol<64>*);
+Symbol_table::override_with_special<64>(Sized_symbol<64>*,
+ const Sized_symbol<64>*);
#endif
} // End namespace gold.
projects / binutils-gdb.git / blobdiff