// resolve.cc -- symbol resolution for gold
+// Copyright (C) 2006-2020 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 "elfcpp.h"
#include "target.h"
#include "object.h"
#include "symtab.h"
+#include "plugin.h"
namespace gold
{
// Symbol methods used in this file.
+// This symbol is being overridden by another symbol whose version is
+// VERSION. Update the VERSION_ field accordingly.
+
+inline void
+Symbol::override_version(const char* version)
+{
+ if (version == NULL)
+ {
+ // This is the case where this symbol is NAME/VERSION, and the
+ // version was not marked as hidden. That makes it the default
+ // version, so we create NAME/NULL. Later we see another symbol
+ // NAME/NULL, and that symbol is overriding this one. In this
+ // case, since NAME/VERSION is the default, we make NAME/NULL
+ // override NAME/VERSION as well. They are already the same
+ // Symbol structure. Setting the VERSION_ field to NULL ensures
+ // that it will be output with the correct, empty, version.
+ this->version_ = version;
+ }
+ else
+ {
+ // This is the case where this symbol is NAME/VERSION_ONE, and
+ // now we see NAME/VERSION_TWO, and NAME/VERSION_TWO is
+ // overriding NAME. If VERSION_ONE and VERSION_TWO are
+ // different, then this can only happen when VERSION_ONE is NULL
+ // and VERSION_TWO is not hidden.
+ gold_assert(this->version_ == version || this->version_ == NULL);
+ this->version_ = version;
+ }
+}
+
+// This symbol is being overidden by another symbol whose visibility
+// is VISIBILITY. Updated the VISIBILITY_ field accordingly.
+
+inline void
+Symbol::override_visibility(elfcpp::STV visibility)
+{
+ // The rule for combining visibility is that we always choose the
+ // most constrained visibility. In order of increasing constraint,
+ // visibility goes PROTECTED, HIDDEN, INTERNAL. This is the reverse
+ // of the numeric values, so the effect is that we always want the
+ // smallest non-zero value.
+ if (visibility != elfcpp::STV_DEFAULT)
+ {
+ if (this->visibility_ == elfcpp::STV_DEFAULT)
+ this->visibility_ = visibility;
+ else if (this->visibility_ > visibility)
+ this->visibility_ = visibility;
+ }
+}
+
// Override the fields in Symbol.
template<int size, bool big_endian>
void
Symbol::override_base(const elfcpp::Sym<size, big_endian>& sym,
- Object* object)
+ unsigned int st_shndx, bool is_ordinary,
+ Object* object, const char* version)
{
- assert(this->source_ == FROM_OBJECT);
- this->u_.from_object.object = object;
- // FIXME: Handle SHN_XINDEX.
- this->u_.from_object.shnum = sym.get_st_shndx();
- this->type_ = sym.get_st_type();
+ gold_assert(this->source_ == FROM_OBJECT);
+ this->u1_.object = object;
+ this->override_version(version);
+ this->u2_.shndx = st_shndx;
+ this->is_ordinary_shndx_ = is_ordinary;
+ // Don't override st_type from plugin placeholder symbols.
+ if (object->pluginobj() == NULL)
+ this->type_ = sym.get_st_type();
this->binding_ = sym.get_st_bind();
- this->visibility_ = sym.get_st_visibility();
+ this->override_visibility(sym.get_st_visibility());
this->nonvis_ = sym.get_st_nonvis();
+ if (object->is_dynamic())
+ this->in_dyn_ = true;
+ else
+ this->in_reg_ = true;
}
// Override the fields in Sized_symbol.
template<bool big_endian>
void
Sized_symbol<size>::override(const elfcpp::Sym<size, big_endian>& sym,
- Object* object)
+ unsigned st_shndx, bool is_ordinary,
+ Object* object, const char* version)
{
- this->override_base(sym, object);
+ this->override_base(sym, st_shndx, is_ordinary, object, version);
this->value_ = sym.get_st_value();
this->symsize_ = sym.get_st_size();
}
-// 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.
+// 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::resolve(Sized_symbol<size>* to,
- const elfcpp::Sym<size, big_endian>& sym,
- Object* object)
+Symbol_table::override(Sized_symbol<size>* tosym,
+ const elfcpp::Sym<size, big_endian>& fromsym,
+ unsigned int st_shndx, bool is_ordinary,
+ Object* object, const char* version)
{
- if (object->target()->has_resolve())
+ tosym->override(fromsym, st_shndx, is_ordinary, object, version);
+ if (tosym->has_alias())
{
- Sized_target<size, big_endian>* sized_target;
- sized_target = object->sized_target
- SELECT_SIZE_ENDIAN_NAME(size, big_endian) (
- SELECT_SIZE_ENDIAN_ONLY(size, big_endian));
- sized_target->resolve(to, sym, object);
- return;
+ Symbol* sym = this->weak_aliases_[tosym];
+ gold_assert(sym != NULL);
+ Sized_symbol<size>* ssym = this->get_sized_symbol<size>(sym);
+ do
+ {
+ ssym->override(fromsym, st_shndx, is_ordinary, object, version);
+ sym = this->weak_aliases_[ssym];
+ gold_assert(sym != NULL);
+ ssym = this->get_sized_symbol<size>(sym);
+ }
+ while (ssym != tosym);
}
+}
- // 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
- // Bits 2-3: 0 for normal, 1 for undefined, 2 for common
- // This gives us values from 0 to 11:
+// 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
+// Bits 2-3: 0 for normal, 1 for undefined, 2 for common
+// This gives us values from 0 to 11.
- enum
- {
- DEF = 0,
- WEAK_DEF = 1,
- DYN_DEF = 2,
- DYN_WEAK_DEF = 3,
- UNDEF = 4,
- WEAK_UNDEF = 5,
- DYN_UNDEF = 6,
- DYN_WEAK_UNDEF = 7,
- COMMON = 8,
- WEAK_COMMON = 9,
- DYN_COMMON = 10,
- DYN_WEAK_COMMON = 11
- };
+static const int global_or_weak_shift = 0;
+static const unsigned int global_flag = 0 << global_or_weak_shift;
+static const unsigned int weak_flag = 1 << global_or_weak_shift;
+
+static const int regular_or_dynamic_shift = 1;
+static const unsigned int regular_flag = 0 << regular_or_dynamic_shift;
+static const unsigned int dynamic_flag = 1 << regular_or_dynamic_shift;
- int tobits;
- switch (to->binding())
+static const int def_undef_or_common_shift = 2;
+static const unsigned int def_flag = 0 << def_undef_or_common_shift;
+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, bool is_ordinary)
+{
+ unsigned int bits;
+
+ switch (binding)
{
case elfcpp::STB_GLOBAL:
- tobits = 0;
+ case elfcpp::STB_GNU_UNIQUE:
+ bits = global_flag;
break;
case elfcpp::STB_WEAK:
- tobits = 1;
+ bits = weak_flag;
break;
case elfcpp::STB_LOCAL:
// We should only see externally visible symbols in the symbol
// table.
- abort();
+ gold_error(_("invalid STB_LOCAL symbol in external symbols"));
+ bits = global_flag;
+ break;
default:
// Any target which wants to handle STB_LOOS, etc., needs to
// define a resolve method.
- abort();
+ gold_error(_("unsupported symbol binding %d"), static_cast<int>(binding));
+ bits = global_flag;
}
- if (to->source() == Symbol::FROM_OBJECT
- && to->object()->is_dynamic())
- tobits |= (1 << 1);
+ if (is_dynamic)
+ bits |= dynamic_flag;
+ else
+ bits |= regular_flag;
- switch (to->shnum())
+ switch (shndx)
{
case elfcpp::SHN_UNDEF:
- tobits |= (1 << 2);
+ bits |= undef_flag;
break;
case elfcpp::SHN_COMMON:
- tobits |= (2 << 2);
+ if (!is_ordinary)
+ bits |= common_flag;
break;
default:
- if (to->type() == elfcpp::STT_COMMON)
- tobits |= (2 << 2);
+ if (!is_ordinary && Symbol::is_common_shndx(shndx))
+ bits |= common_flag;
+ else
+ bits |= def_flag;
break;
}
- int frombits;
- switch (sym.get_st_bind())
- {
- case elfcpp::STB_GLOBAL:
- frombits = 0;
- break;
-
- case elfcpp::STB_WEAK:
- frombits = 1;
- break;
+ return bits;
+}
- 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);
+// Resolve a symbol. This is called the second and subsequent times
+// we see a symbol. TO is the pre-existing symbol. ST_SHNDX is the
+// section index for SYM, possibly adjusted for many sections.
+// IS_ORDINARY is whether ST_SHNDX is a normal section index rather
+// than a special code. ORIG_ST_SHNDX is the original section index,
+// before any munging because of discarded sections, except that all
+// non-ordinary section indexes are mapped to SHN_UNDEF. VERSION is
+// the version of SYM.
- 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);
+template<int size, bool big_endian>
+void
+Symbol_table::resolve(Sized_symbol<size>* to,
+ const elfcpp::Sym<size, big_endian>& sym,
+ unsigned int st_shndx, bool is_ordinary,
+ unsigned int orig_st_shndx,
+ Object* object, const char* version,
+ bool is_default_version)
+{
+ bool to_is_ordinary;
+ const unsigned int to_shndx = to->shndx(&to_is_ordinary);
+
+ // It's possible for a symbol to be defined in an object file
+ // using .symver to give it a version, and for there to also be
+ // a linker script giving that symbol the same version. We
+ // don't want to give a multiple-definition error for this
+ // harmless redefinition.
+ if (to->source() == Symbol::FROM_OBJECT
+ && to->object() == object
+ && to->is_defined()
+ && is_ordinary
+ && to_is_ordinary
+ && to_shndx == st_shndx
+ && to->value() == sym.get_st_value())
+ return;
+
+ // Likewise for an absolute symbol defined twice with the same value.
+ if (!is_ordinary
+ && st_shndx == elfcpp::SHN_ABS
+ && !to_is_ordinary
+ && to_shndx == elfcpp::SHN_ABS
+ && to->value() == sym.get_st_value())
+ return;
+
+ if (parameters->target().has_resolve())
+ {
+ Sized_target<size, big_endian>* sized_target;
+ sized_target = parameters->sized_target<size, big_endian>();
+ if (sized_target->resolve(to, sym, object, version))
+ return;
}
- if (object->is_dynamic())
+ if (!object->is_dynamic())
+ {
+ if (sym.get_st_type() == elfcpp::STT_COMMON
+ && (is_ordinary || !Symbol::is_common_shndx(st_shndx)))
+ {
+ gold_warning(_("STT_COMMON symbol '%s' in %s "
+ "is not in a common section"),
+ to->demangled_name().c_str(),
+ to->object()->name().c_str());
+ return;
+ }
+ // Record that we've seen this symbol in a regular object.
+ to->set_in_reg();
+ }
+ else if (st_shndx == elfcpp::SHN_UNDEF
+ && (to->visibility() == elfcpp::STV_HIDDEN
+ || to->visibility() == elfcpp::STV_INTERNAL))
+ {
+ // The symbol is hidden, so a reference from a shared object
+ // cannot bind to it. We tried issuing a warning in this case,
+ // but that produces false positives when the symbol is
+ // actually resolved in a different shared object (PR 15574).
+ return;
+ }
+ else
{
- frombits |= (1 << 1);
-
// Record that we've seen this symbol in a dynamic object.
to->set_in_dyn();
}
- switch (sym.get_st_shndx())
+ // Record if we've seen this symbol in a real ELF object (i.e., the
+ // symbol is referenced from outside the world known to the plugin).
+ if (object->pluginobj() == NULL && !object->is_dynamic())
+ to->set_in_real_elf();
+
+ // If we're processing replacement files, allow new symbols to override
+ // the placeholders from the plugin objects.
+ // Treat common symbols specially since it is possible that an ELF
+ // file increased the size of the alignment.
+ if (to->source() == Symbol::FROM_OBJECT)
{
- case elfcpp::SHN_UNDEF:
- frombits |= (1 << 2);
- break;
+ Pluginobj* obj = to->object()->pluginobj();
+ if (obj != NULL
+ && parameters->options().plugins()->in_replacement_phase())
+ {
+ bool adjust_common = false;
+ typename Sized_symbol<size>::Size_type tosize = 0;
+ typename Sized_symbol<size>::Value_type tovalue = 0;
+ if (to->is_common()
+ && !is_ordinary && Symbol::is_common_shndx(st_shndx))
+ {
+ adjust_common = true;
+ tosize = to->symsize();
+ tovalue = to->value();
+ }
+ this->override(to, sym, st_shndx, is_ordinary, object, version);
+ if (adjust_common)
+ {
+ if (tosize > to->symsize())
+ to->set_symsize(tosize);
+ if (tovalue > to->value())
+ to->set_value(tovalue);
+ }
+ return;
+ }
+ }
- case elfcpp::SHN_COMMON:
- frombits |= (2 << 2);
- break;
+ // 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. We also check
+ // combinations of weak and strong, which might occur if one case is
+ // inline and the other is not. (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.)
+ if (parameters->options().detect_odr_violations()
+ && (sym.get_st_bind() == elfcpp::STB_WEAK
+ || to->binding() == elfcpp::STB_WEAK)
+ && orig_st_shndx != elfcpp::SHN_UNDEF
+ && to_is_ordinary
+ && to_shndx != elfcpp::SHN_UNDEF
+ && sym.get_st_size() != 0 // Ignore weird 0-sized symbols.
+ && to->symsize() != 0
+ && (sym.get_st_type() != to->type()
+ || 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_st_shndx, static_cast<off_t>(sym.get_st_value()) };
+ Symbol_location toloc = { to->object(), to_shndx,
+ static_cast<off_t>(to->value()) };
+ this->candidate_odr_violations_[to->name()].insert(fromloc);
+ this->candidate_odr_violations_[to->name()].insert(toloc);
+ }
- default:
- if (sym.get_st_type() == elfcpp::STT_COMMON)
- frombits |= (2 << 2);
- break;
+ // Plugins don't provide a symbol type, so adopt the existing type
+ // if the FROM symbol is from a plugin.
+ elfcpp::STT fromtype = (object->pluginobj() != NULL
+ ? to->type()
+ : sym.get_st_type());
+ unsigned int frombits = symbol_to_bits(sym.get_st_bind(),
+ object->is_dynamic(),
+ st_shndx, is_ordinary);
+
+ bool adjust_common_sizes;
+ bool adjust_dyndef;
+ typename Sized_symbol<size>::Size_type tosize = to->symsize();
+ if (Symbol_table::should_override(to, frombits, fromtype, OBJECT,
+ object, &adjust_common_sizes,
+ &adjust_dyndef, is_default_version))
+ {
+ elfcpp::STB orig_tobinding = to->binding();
+ typename Sized_symbol<size>::Value_type tovalue = to->value();
+ this->override(to, sym, st_shndx, is_ordinary, object, version);
+ if (adjust_common_sizes)
+ {
+ if (tosize > to->symsize())
+ to->set_symsize(tosize);
+ if (tovalue > to->value())
+ to->set_value(tovalue);
+ }
+ if (adjust_dyndef)
+ {
+ // We are overriding an UNDEF or WEAK UNDEF with a DYN DEF.
+ // Remember which kind of UNDEF it was for future reference.
+ to->set_undef_binding(orig_tobinding);
+ }
+ }
+ else
+ {
+ if (adjust_common_sizes)
+ {
+ if (sym.get_st_size() > tosize)
+ to->set_symsize(sym.get_st_size());
+ if (sym.get_st_value() > to->value())
+ to->set_value(sym.get_st_value());
+ }
+ if (adjust_dyndef)
+ {
+ // We are keeping a DYN DEF after seeing an UNDEF or WEAK UNDEF.
+ // Remember which kind of UNDEF it was.
+ to->set_undef_binding(sym.get_st_bind());
+ }
+ // The ELF ABI says that even for a reference to a symbol we
+ // merge the visibility.
+ to->override_visibility(sym.get_st_visibility());
+ }
+
+ // If we have a non-WEAK reference from a regular object to a
+ // dynamic object, mark the dynamic object as needed.
+ if (to->is_from_dynobj() && to->in_reg() && !to->is_undef_binding_weak())
+ to->object()->set_is_needed();
+
+ if (adjust_common_sizes && parameters->options().warn_common())
+ {
+ if (tosize > sym.get_st_size())
+ Symbol_table::report_resolve_problem(false,
+ _("common of '%s' overriding "
+ "smaller common"),
+ to, OBJECT, object);
+ else if (tosize < sym.get_st_size())
+ Symbol_table::report_resolve_problem(false,
+ _("common of '%s' overidden by "
+ "larger common"),
+ to, OBJECT, object);
+ else
+ Symbol_table::report_resolve_problem(false,
+ _("multiple common of '%s'"),
+ to, OBJECT, object);
}
+}
- if ((tobits & (1 << 1)) != (frombits & (1 << 1)))
+// Handle the core of symbol resolution. This is called with the
+// existing symbol, TO, and a bitflag describing the new symbol. This
+// returns true if we should override the existing symbol with the new
+// one, and returns false otherwise. It sets *ADJUST_COMMON_SIZES to
+// true if we should set the symbol size to the maximum of the TO and
+// FROM sizes. It handles error conditions.
+
+bool
+Symbol_table::should_override(const Symbol* to, unsigned int frombits,
+ elfcpp::STT fromtype, Defined defined,
+ Object* object, bool* adjust_common_sizes,
+ bool* adjust_dyndef, bool is_default_version)
+{
+ *adjust_common_sizes = false;
+ *adjust_dyndef = false;
+
+ unsigned int tobits;
+ if (to->source() == Symbol::IS_UNDEFINED)
+ tobits = symbol_to_bits(to->binding(), false, elfcpp::SHN_UNDEF, true);
+ else if (to->source() != Symbol::FROM_OBJECT)
+ tobits = symbol_to_bits(to->binding(), false, elfcpp::SHN_ABS, false);
+ else
{
- // This symbol is seen in both a dynamic object and a regular
- // object. That means that we need the symbol to go into the
- // dynamic symbol table, so that the dynamic linker can use the
- // regular symbol to override or define the dynamic symbol.
- to->set_needs_dynsym_entry();
+ bool is_ordinary;
+ unsigned int shndx = to->shndx(&is_ordinary);
+ tobits = symbol_to_bits(to->binding(),
+ to->object()->is_dynamic(),
+ shndx,
+ is_ordinary);
}
- // FIXME: Warn if either but not both of TO and SYM are STT_TLS.
+ if ((to->type() == elfcpp::STT_TLS) ^ (fromtype == elfcpp::STT_TLS)
+ && !to->is_placeholder())
+ Symbol_table::report_resolve_problem(true,
+ _("symbol '%s' used as both __thread "
+ "and non-__thread"),
+ to, defined, object);
// We use a giant switch table for symbol resolution. This code is
// unwieldy, but: 1) it is efficient; 2) we definitely handle all
// but that is no easier to understand than this large switch
// statement.
+ // These are the values generated by the bit codes.
+ enum
+ {
+ DEF = global_flag | regular_flag | def_flag,
+ WEAK_DEF = weak_flag | regular_flag | def_flag,
+ DYN_DEF = global_flag | dynamic_flag | def_flag,
+ DYN_WEAK_DEF = weak_flag | dynamic_flag | def_flag,
+ UNDEF = global_flag | regular_flag | undef_flag,
+ WEAK_UNDEF = weak_flag | regular_flag | undef_flag,
+ DYN_UNDEF = global_flag | dynamic_flag | undef_flag,
+ DYN_WEAK_UNDEF = weak_flag | dynamic_flag | undef_flag,
+ COMMON = global_flag | regular_flag | common_flag,
+ WEAK_COMMON = weak_flag | regular_flag | common_flag,
+ DYN_COMMON = global_flag | dynamic_flag | common_flag,
+ DYN_WEAK_COMMON = weak_flag | dynamic_flag | common_flag
+ };
+
switch (tobits * 16 + frombits)
{
case DEF * 16 + DEF:
// Two definitions of the same symbol.
- fprintf(stderr, "%s: %s: multiple definition of %s\n",
- program_name, object->name().c_str(), to->name());
- // FIXME: Report locations. Record that we have seen an error.
- return;
+
+ // If either symbol is defined by an object included using
+ // --just-symbols, then don't warn. This is for compatibility
+ // with the GNU linker. FIXME: This is a hack.
+ if ((to->source() == Symbol::FROM_OBJECT && to->object()->just_symbols())
+ || (object != NULL && object->just_symbols()))
+ return false;
+
+ if (!parameters->options().muldefs())
+ Symbol_table::report_resolve_problem(true,
+ _("multiple definition of '%s'"),
+ to, defined, object);
+ return false;
case WEAK_DEF * 16 + DEF:
// We've seen a weak definition, and now we see a strong
// are currently compatible with the GNU linker. In the future
// we should add a target specific option to change this.
// FIXME.
- to->override(sym, object);
- return;
+ return true;
case DYN_DEF * 16 + DEF:
case DYN_WEAK_DEF * 16 + DEF:
// definition in a regular object. The definition in the
// regular object overrides the definition in the dynamic
// object.
- to->override(sym, object);
- return;
+ return true;
case UNDEF * 16 + DEF:
case WEAK_UNDEF * 16 + DEF:
case DYN_WEAK_UNDEF * 16 + DEF:
// We've seen an undefined reference, and now we see a
// definition. We use the definition.
- to->override(sym, object);
- return;
+ return true;
case COMMON * 16 + DEF:
case WEAK_COMMON * 16 + DEF:
case DYN_COMMON * 16 + DEF:
case DYN_WEAK_COMMON * 16 + DEF:
// We've seen a common symbol and now we see a definition. The
- // definition overrides. FIXME: We should optionally issue a
- // warning.
- to->override(sym, object);
- return;
+ // definition overrides.
+ if (parameters->options().warn_common())
+ Symbol_table::report_resolve_problem(false,
+ _("definition of '%s' overriding "
+ "common"),
+ to, defined, object);
+ return true;
case DEF * 16 + WEAK_DEF:
case WEAK_DEF * 16 + WEAK_DEF:
// We've seen a definition and now we see a weak definition. We
// ignore the new weak definition.
- return;
+ return false;
case DYN_DEF * 16 + WEAK_DEF:
case DYN_WEAK_DEF * 16 + WEAK_DEF:
// We've seen a dynamic definition and now we see a regular weak
// definition. The regular weak definition overrides.
- to->override(sym, object);
- return;
+ return true;
case UNDEF * 16 + WEAK_DEF:
case WEAK_UNDEF * 16 + WEAK_DEF:
case DYN_UNDEF * 16 + WEAK_DEF:
case DYN_WEAK_UNDEF * 16 + WEAK_DEF:
// A weak definition of a currently undefined symbol.
- to->override(sym, object);
- return;
+ return true;
case COMMON * 16 + WEAK_DEF:
case WEAK_COMMON * 16 + WEAK_DEF:
// A weak definition does not override a common definition.
- return;
+ return false;
case DYN_COMMON * 16 + WEAK_DEF:
case DYN_WEAK_COMMON * 16 + WEAK_DEF:
// A weak definition does override a definition in a dynamic
- // object. FIXME: We should optionally issue a warning.
- to->override(sym, object);
- return;
+ // object.
+ if (parameters->options().warn_common())
+ Symbol_table::report_resolve_problem(false,
+ _("definition of '%s' overriding "
+ "dynamic common definition"),
+ to, defined, object);
+ return true;
case DEF * 16 + DYN_DEF:
case WEAK_DEF * 16 + DYN_DEF:
+ // Ignore a dynamic definition if we already have a definition.
+ return false;
+
case DYN_DEF * 16 + DYN_DEF:
case DYN_WEAK_DEF * 16 + DYN_DEF:
- // Ignore a dynamic definition if we already have a definition.
- return;
+ // Ignore a dynamic definition if we already have a definition,
+ // unless the existing definition is an unversioned definition
+ // in the same dynamic object, and the new definition is a
+ // default version.
+ if (to->object() == object
+ && to->version() == NULL
+ && is_default_version)
+ return true;
+ // Or, if the existing definition is in an unused --as-needed library,
+ // and the reference is weak, let the new definition override.
+ if (to->in_reg()
+ && to->is_undef_binding_weak()
+ && to->object()->as_needed()
+ && !to->object()->is_needed())
+ return true;
+ return false;
case UNDEF * 16 + DYN_DEF:
- case WEAK_UNDEF * 16 + DYN_DEF:
case DYN_UNDEF * 16 + DYN_DEF:
case DYN_WEAK_UNDEF * 16 + DYN_DEF:
// Use a dynamic definition if we have a reference.
- to->override(sym, object);
- return;
+ return true;
+
+ case WEAK_UNDEF * 16 + DYN_DEF:
+ // When overriding a weak undef by a dynamic definition,
+ // we need to remember that the original undef was weak.
+ *adjust_dyndef = true;
+ return true;
case COMMON * 16 + DYN_DEF:
case WEAK_COMMON * 16 + DYN_DEF:
- case DYN_COMMON * 16 + DYN_DEF:
- case DYN_WEAK_COMMON * 16 + DYN_DEF:
// Ignore a dynamic definition if we already have a common
// definition.
- return;
+ return false;
case DEF * 16 + DYN_WEAK_DEF:
case WEAK_DEF * 16 + DYN_WEAK_DEF:
- case DYN_DEF * 16 + DYN_WEAK_DEF:
- case DYN_WEAK_DEF * 16 + DYN_WEAK_DEF:
// Ignore a weak dynamic definition if we already have a
// definition.
- return;
+ return false;
case UNDEF * 16 + DYN_WEAK_DEF:
- case WEAK_UNDEF * 16 + DYN_WEAK_DEF:
+ // When overriding an undef by a dynamic weak definition,
+ // we need to remember that the original undef was not weak.
+ *adjust_dyndef = true;
+ return true;
+
case DYN_UNDEF * 16 + DYN_WEAK_DEF:
case DYN_WEAK_UNDEF * 16 + DYN_WEAK_DEF:
// Use a weak dynamic definition if we have a reference.
- to->override(sym, object);
- return;
+ return true;
+
+ case WEAK_UNDEF * 16 + DYN_WEAK_DEF:
+ // When overriding a weak undef by a dynamic definition,
+ // we need to remember that the original undef was weak.
+ *adjust_dyndef = true;
+ return true;
case COMMON * 16 + DYN_WEAK_DEF:
case WEAK_COMMON * 16 + DYN_WEAK_DEF:
- case DYN_COMMON * 16 + DYN_WEAK_DEF:
- case DYN_WEAK_COMMON * 16 + DYN_WEAK_DEF:
// Ignore a weak dynamic definition if we already have a common
// definition.
- return;
+ return false;
+
+ case DYN_COMMON * 16 + DYN_DEF:
+ case DYN_WEAK_COMMON * 16 + DYN_DEF:
+ case DYN_DEF * 16 + DYN_WEAK_DEF:
+ case DYN_WEAK_DEF * 16 + DYN_WEAK_DEF:
+ case DYN_COMMON * 16 + DYN_WEAK_DEF:
+ case DYN_WEAK_COMMON * 16 + DYN_WEAK_DEF:
+ // If the existing definition is in an unused --as-needed library,
+ // and the reference is weak, let a new dynamic definition override.
+ if (to->in_reg()
+ && to->is_undef_binding_weak()
+ && to->object()->as_needed()
+ && !to->object()->is_needed())
+ return true;
+ return false;
case DEF * 16 + UNDEF:
case WEAK_DEF * 16 + UNDEF:
- case DYN_DEF * 16 + UNDEF:
- case DYN_WEAK_DEF * 16 + UNDEF:
case UNDEF * 16 + UNDEF:
// A new undefined reference tells us nothing.
- return;
+ return false;
+
+ case DYN_DEF * 16 + UNDEF:
+ case DYN_WEAK_DEF * 16 + UNDEF:
+ // For a dynamic def, we need to remember which kind of undef we see.
+ *adjust_dyndef = true;
+ return false;
case WEAK_UNDEF * 16 + UNDEF:
case DYN_UNDEF * 16 + UNDEF:
case DYN_WEAK_UNDEF * 16 + UNDEF:
// A strong undef overrides a dynamic or weak undef.
- to->override(sym, object);
- return;
+ return true;
case COMMON * 16 + UNDEF:
case WEAK_COMMON * 16 + UNDEF:
case DYN_COMMON * 16 + UNDEF:
case DYN_WEAK_COMMON * 16 + UNDEF:
// A new undefined reference tells us nothing.
- return;
+ return false;
case DEF * 16 + WEAK_UNDEF:
case WEAK_DEF * 16 + WEAK_UNDEF:
- case DYN_DEF * 16 + WEAK_UNDEF:
- case DYN_WEAK_DEF * 16 + WEAK_UNDEF:
case UNDEF * 16 + WEAK_UNDEF:
case WEAK_UNDEF * 16 + WEAK_UNDEF:
case DYN_UNDEF * 16 + WEAK_UNDEF:
- case DYN_WEAK_UNDEF * 16 + WEAK_UNDEF:
case COMMON * 16 + WEAK_UNDEF:
case WEAK_COMMON * 16 + WEAK_UNDEF:
case DYN_COMMON * 16 + WEAK_UNDEF:
case DYN_WEAK_COMMON * 16 + WEAK_UNDEF:
- // A new weak undefined reference tells us nothing.
- return;
+ // A new weak undefined reference tells us nothing unless the
+ // exisiting symbol is a dynamic weak reference.
+ return false;
+
+ case DYN_WEAK_UNDEF * 16 + WEAK_UNDEF:
+ // A new weak reference overrides an existing dynamic weak reference.
+ // This is necessary because a dynamic weak reference remembers
+ // the old binding, which may not be weak. If we keeps the existing
+ // dynamic weak reference, the weakness may be dropped in the output.
+ return true;
+
+ case DYN_DEF * 16 + WEAK_UNDEF:
+ case DYN_WEAK_DEF * 16 + WEAK_UNDEF:
+ // For a dynamic def, we need to remember which kind of undef we see.
+ *adjust_dyndef = true;
+ return false;
case DEF * 16 + DYN_UNDEF:
case WEAK_DEF * 16 + DYN_UNDEF:
case DYN_COMMON * 16 + DYN_UNDEF:
case DYN_WEAK_COMMON * 16 + DYN_UNDEF:
// A new dynamic undefined reference tells us nothing.
- return;
+ return false;
case DEF * 16 + DYN_WEAK_UNDEF:
case WEAK_DEF * 16 + DYN_WEAK_UNDEF:
case DYN_COMMON * 16 + DYN_WEAK_UNDEF:
case DYN_WEAK_COMMON * 16 + DYN_WEAK_UNDEF:
// A new weak dynamic undefined reference tells us nothing.
- return;
+ return false;
case DEF * 16 + COMMON:
// A common symbol does not override a definition.
- return;
+ if (parameters->options().warn_common())
+ Symbol_table::report_resolve_problem(false,
+ _("common '%s' overridden by "
+ "previous definition"),
+ to, defined, object);
+ return false;
case WEAK_DEF * 16 + COMMON:
case DYN_DEF * 16 + COMMON:
case DYN_WEAK_DEF * 16 + COMMON:
// A common symbol does override a weak definition or a dynamic
// definition.
- to->override(sym, object);
- return;
+ return true;
case UNDEF * 16 + COMMON:
case WEAK_UNDEF * 16 + COMMON:
case DYN_UNDEF * 16 + COMMON:
case DYN_WEAK_UNDEF * 16 + COMMON:
// A common symbol is a definition for a reference.
- to->override(sym, object);
- return;
+ return true;
case COMMON * 16 + COMMON:
// Set the size to the maximum.
- if (sym.get_st_size() > to->symsize())
- to->set_symsize(sym.get_st_size());
- return;
+ *adjust_common_sizes = true;
+ return false;
case WEAK_COMMON * 16 + COMMON:
// I'm not sure just what a weak common symbol means, but
// presumably it can be overridden by a regular common symbol.
- to->override(sym, object);
- return;
+ return true;
case DYN_COMMON * 16 + COMMON:
case DYN_WEAK_COMMON * 16 + COMMON:
- {
- // Use the real common symbol, but adjust the size if necessary.
- typename Sized_symbol<size>::Size_type symsize = to->symsize();
- to->override(sym, object);
- if (to->symsize() < symsize)
- to->set_symsize(symsize);
- }
- return;
+ // Use the real common symbol, but adjust the size if necessary.
+ *adjust_common_sizes = true;
+ return true;
case DEF * 16 + WEAK_COMMON:
case WEAK_DEF * 16 + WEAK_COMMON:
case DYN_WEAK_DEF * 16 + WEAK_COMMON:
// Whatever a weak common symbol is, it won't override a
// definition.
- return;
+ return false;
case UNDEF * 16 + WEAK_COMMON:
case WEAK_UNDEF * 16 + WEAK_COMMON:
case DYN_UNDEF * 16 + WEAK_COMMON:
case DYN_WEAK_UNDEF * 16 + WEAK_COMMON:
// A weak common symbol is better than an undefined symbol.
- to->override(sym, object);
- return;
+ return true;
case COMMON * 16 + WEAK_COMMON:
case WEAK_COMMON * 16 + WEAK_COMMON:
case DYN_WEAK_COMMON * 16 + WEAK_COMMON:
// Ignore a weak common symbol in the presence of a real common
// symbol.
- return;
+ return false;
case DEF * 16 + DYN_COMMON:
case WEAK_DEF * 16 + DYN_COMMON:
case DYN_WEAK_DEF * 16 + DYN_COMMON:
// Ignore a dynamic common symbol in the presence of a
// definition.
- return;
+ return false;
case UNDEF * 16 + DYN_COMMON:
case WEAK_UNDEF * 16 + DYN_COMMON:
case DYN_UNDEF * 16 + DYN_COMMON:
case DYN_WEAK_UNDEF * 16 + DYN_COMMON:
// A dynamic common symbol is a definition of sorts.
- to->override(sym, object);
- return;
+ return true;
case COMMON * 16 + DYN_COMMON:
case WEAK_COMMON * 16 + DYN_COMMON:
case DYN_COMMON * 16 + DYN_COMMON:
case DYN_WEAK_COMMON * 16 + DYN_COMMON:
// Set the size to the maximum.
- if (sym.get_st_size() > to->symsize())
- to->set_symsize(sym.get_st_size());
- return;
+ *adjust_common_sizes = true;
+ return false;
case DEF * 16 + DYN_WEAK_COMMON:
case WEAK_DEF * 16 + DYN_WEAK_COMMON:
case DYN_DEF * 16 + DYN_WEAK_COMMON:
case DYN_WEAK_DEF * 16 + DYN_WEAK_COMMON:
// A common symbol is ignored in the face of a definition.
- return;
+ return false;
case UNDEF * 16 + DYN_WEAK_COMMON:
case WEAK_UNDEF * 16 + DYN_WEAK_COMMON:
case DYN_UNDEF * 16 + DYN_WEAK_COMMON:
case DYN_WEAK_UNDEF * 16 + DYN_WEAK_COMMON:
// I guess a weak common symbol is better than a definition.
- to->override(sym, object);
- return;
+ return true;
case COMMON * 16 + DYN_WEAK_COMMON:
case WEAK_COMMON * 16 + DYN_WEAK_COMMON:
case DYN_COMMON * 16 + DYN_WEAK_COMMON:
case DYN_WEAK_COMMON * 16 + DYN_WEAK_COMMON:
// Set the size to the maximum.
- if (sym.get_st_size() > to->symsize())
- to->set_symsize(sym.get_st_size());
- return;
+ *adjust_common_sizes = true;
+ return false;
+
+ default:
+ gold_unreachable();
+ }
+}
+
+// Issue an error or warning due to symbol resolution. IS_ERROR
+// indicates an error rather than a warning. MSG is the error
+// message; it is expected to have a %s for the symbol name. TO is
+// the existing symbol. DEFINED/OBJECT is where the new symbol was
+// found.
+
+// FIXME: We should have better location information here. When the
+// symbol is defined, we should be able to pull the location from the
+// debug info if there is any.
+
+void
+Symbol_table::report_resolve_problem(bool is_error, const char* msg,
+ const Symbol* to, Defined defined,
+ Object* object)
+{
+ std::string demangled(to->demangled_name());
+ size_t len = strlen(msg) + demangled.length() + 10;
+ char* buf = new char[len];
+ snprintf(buf, len, msg, demangled.c_str());
+
+ const char* objname;
+ switch (defined)
+ {
+ case OBJECT:
+ objname = object->name().c_str();
+ break;
+ case COPY:
+ objname = _("COPY reloc");
+ break;
+ case DEFSYM:
+ case UNDEFINED:
+ objname = _("command line");
+ break;
+ case SCRIPT:
+ objname = _("linker script");
+ break;
+ case PREDEFINED:
+ case INCREMENTAL_BASE:
+ objname = _("linker defined");
+ break;
+ default:
+ gold_unreachable();
+ }
+
+ if (is_error)
+ gold_error("%s: %s", objname, buf);
+ else
+ gold_warning("%s: %s", objname, buf);
+
+ delete[] buf;
+ if (to->source() == Symbol::FROM_OBJECT)
+ objname = to->object()->name().c_str();
+ else
+ objname = _("command line");
+ gold_info("%s: %s: previous definition here", program_name, objname);
+}
+
+// Completely override existing symbol. Everything bar name_,
+// version_, and is_forced_local_ flag are copied. version_ is
+// cleared if from->version_ is clear. Returns true if this symbol
+// should be forced local.
+bool
+Symbol::clone(const Symbol* from)
+{
+ // Don't allow cloning after dynamic linking info is attached to symbols.
+ // We aren't prepared to merge such.
+ gold_assert(!this->has_symtab_index() && !from->has_symtab_index());
+ gold_assert(!this->has_dynsym_index() && !from->has_dynsym_index());
+ gold_assert(this->got_offset_list() == NULL
+ && from->got_offset_list() == NULL);
+ gold_assert(!this->has_plt_offset() && !from->has_plt_offset());
+
+ if (!from->version_)
+ this->version_ = from->version_;
+ this->u1_ = from->u1_;
+ this->u2_ = from->u2_;
+ this->type_ = from->type_;
+ this->binding_ = from->binding_;
+ this->visibility_ = from->visibility_;
+ this->nonvis_ = from->nonvis_;
+ this->source_ = from->source_;
+ this->is_def_ = from->is_def_;
+ this->is_forwarder_ = from->is_forwarder_;
+ this->has_alias_ = from->has_alias_;
+ this->needs_dynsym_entry_ = from->needs_dynsym_entry_;
+ this->in_reg_ = from->in_reg_;
+ this->in_dyn_ = from->in_dyn_;
+ this->needs_dynsym_value_ = from->needs_dynsym_value_;
+ this->has_warning_ = from->has_warning_;
+ this->is_copied_from_dynobj_ = from->is_copied_from_dynobj_;
+ this->is_ordinary_shndx_ = from->is_ordinary_shndx_;
+ this->in_real_elf_ = from->in_real_elf_;
+ this->is_defined_in_discarded_section_
+ = from->is_defined_in_discarded_section_;
+ this->undef_binding_set_ = from->undef_binding_set_;
+ this->undef_binding_weak_ = from->undef_binding_weak_;
+ this->is_predefined_ = from->is_predefined_;
+ this->is_protected_ = from->is_protected_;
+ this->non_zero_localentry_ = from->non_zero_localentry_;
+
+ return !this->is_forced_local_ && from->is_forced_local_;
+}
+
+template <int size>
+bool
+Sized_symbol<size>::clone(const Sized_symbol<size>* from)
+{
+ this->value_ = from->value_;
+ this->symsize_ = from->symsize_;
+ return Symbol::clone(from);
+}
+
+// A special case of should_override which is only called for a strong
+// defined symbol from a regular object file. This is used when
+// defining special symbols.
+
+bool
+Symbol_table::should_override_with_special(const Symbol* to,
+ elfcpp::STT fromtype,
+ Defined defined)
+{
+ bool adjust_common_sizes;
+ bool adjust_dyn_def;
+ unsigned int frombits = global_flag | regular_flag | def_flag;
+ bool ret = Symbol_table::should_override(to, frombits, fromtype, defined,
+ NULL, &adjust_common_sizes,
+ &adjust_dyn_def, false);
+ gold_assert(!adjust_common_sizes && !adjust_dyn_def);
+ return ret;
+}
+
+// Override symbol base with a special symbol.
+
+void
+Symbol::override_base_with_special(const Symbol* from)
+{
+ bool same_name = this->name_ == from->name_;
+ gold_assert(same_name || this->has_alias());
+
+ // If we are overriding an undef, remember the original binding.
+ if (this->is_undefined())
+ this->set_undef_binding(this->binding_);
+
+ this->source_ = from->source_;
+ switch (from->source_)
+ {
+ case FROM_OBJECT:
+ case IN_OUTPUT_DATA:
+ case IN_OUTPUT_SEGMENT:
+ this->u1_ = from->u1_;
+ this->u2_ = from->u2_;
+ break;
+ case IS_CONSTANT:
+ case IS_UNDEFINED:
+ break;
default:
- abort();
+ gold_unreachable();
+ break;
+ }
+
+ if (same_name)
+ {
+ // When overriding a versioned symbol with a special symbol, we
+ // may be changing the version. This will happen if we see a
+ // special symbol such as "_end" defined in a shared object with
+ // one version (from a version script), but we want to define it
+ // here with a different version (from a different version
+ // script).
+ this->version_ = from->version_;
+ }
+ this->type_ = from->type_;
+ this->binding_ = from->binding_;
+ this->override_visibility(from->visibility_);
+ this->nonvis_ = from->nonvis_;
+
+ // 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;
+
+ this->is_predefined_ = from->is_predefined_;
+
+ // We shouldn't see these flags. If we do, we need to handle them
+ // somehow.
+ gold_assert(!from->is_forwarder_);
+ gold_assert(!from->has_plt_offset());
+ gold_assert(!from->has_warning_);
+ gold_assert(!from->is_copied_from_dynobj_);
+ gold_assert(!from->is_forced_local_);
+}
+
+// Override a symbol with a special symbol.
+
+template<int size>
+void
+Sized_symbol<size>::override_with_special(const Sized_symbol<size>* from)
+{
+ this->override_base_with_special(from);
+ this->value_ = from->value_;
+ 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 = this->get_sized_symbol<size>(sym);
+ do
+ {
+ ssym->override_with_special(fromsym);
+ sym = this->weak_aliases_[ssym];
+ gold_assert(sym != NULL);
+ ssym = this->get_sized_symbol<size>(sym);
+ }
+ while (ssym != tosym);
}
+ if (tosym->binding() == elfcpp::STB_LOCAL
+ || ((tosym->visibility() == elfcpp::STV_HIDDEN
+ || tosym->visibility() == elfcpp::STV_INTERNAL)
+ && (tosym->binding() == elfcpp::STB_GLOBAL
+ || tosym->binding() == elfcpp::STB_GNU_UNIQUE
+ || tosym->binding() == elfcpp::STB_WEAK)
+ && !parameters->options().relocatable()))
+ this->force_local(tosym);
}
// Instantiate the templates we need. We could use the configure
// script to restrict this to only the ones needed for implemented
// targets.
+// We have to instantiate both big and little endian versions because
+// these are used by other templates that depends on size only.
+
+#if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
template
void
-Symbol_table::resolve<32, true>(
+Symbol_table::resolve<32, false>(
Sized_symbol<32>* to,
- const elfcpp::Sym<32, true>& sym,
- Object* object);
+ const elfcpp::Sym<32, false>& sym,
+ unsigned int st_shndx,
+ bool is_ordinary,
+ unsigned int orig_st_shndx,
+ Object* object,
+ const char* version,
+ bool is_default_version);
template
void
-Symbol_table::resolve<32, false>(
+Symbol_table::resolve<32, true>(
Sized_symbol<32>* to,
- const elfcpp::Sym<32, false>& sym,
- Object* object);
+ const elfcpp::Sym<32, true>& sym,
+ unsigned int st_shndx,
+ bool is_ordinary,
+ unsigned int orig_st_shndx,
+ Object* object,
+ const char* version,
+ bool is_default_version);
+#endif
+
+#if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
+template
+void
+Symbol_table::resolve<64, false>(
+ Sized_symbol<64>* to,
+ const elfcpp::Sym<64, false>& sym,
+ unsigned int st_shndx,
+ bool is_ordinary,
+ unsigned int orig_st_shndx,
+ Object* object,
+ const char* version,
+ bool is_default_version);
template
void
Symbol_table::resolve<64, true>(
Sized_symbol<64>* to,
const elfcpp::Sym<64, true>& sym,
- Object* object);
+ unsigned int st_shndx,
+ bool is_ordinary,
+ unsigned int orig_st_shndx,
+ Object* object,
+ const char* version,
+ bool is_default_version);
+#endif
+
+#if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
+template
+void
+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
-Symbol_table::resolve<64, false>(
- Sized_symbol<64>* to,
- const elfcpp::Sym<64, false>& sym,
- Object* object);
+Symbol_table::override_with_special<64>(Sized_symbol<64>*,
+ const Sized_symbol<64>*);
+#endif
+template
+bool
+Sized_symbol<32>::clone(const Sized_symbol<32>*);
+
+template
+bool
+Sized_symbol<64>::clone(const Sized_symbol<64>*);
} // End namespace gold.
projects / deliverable / binutils-gdb.git / blobdiff