// resolve.cc -- symbol resolution for gold
-// Copyright 2006, 2007, 2008 Free Software Foundation, Inc.
+// Copyright 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
// Written by Ian Lance Taylor <iant@google.com>.
// This file is part of gold.
#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>
{
gold_assert(this->source_ == FROM_OBJECT);
this->u_.from_object.object = object;
- if (version != NULL && this->version() != version)
- {
- gold_assert(this->version() == NULL);
- this->version_ = version;
- }
+ this->override_version(version);
this->u_.from_object.shndx = st_shndx;
this->is_ordinary_shndx_ = is_ordinary;
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;
switch (binding)
{
case elfcpp::STB_GLOBAL:
+ case elfcpp::STB_GNU_UNIQUE:
bits = global_flag;
break;
default:
if (type == elfcpp::STT_COMMON)
bits |= common_flag;
+ else if (!is_ordinary && Symbol::is_common_shndx(shndx))
+ bits |= common_flag;
else
bits |= def_flag;
break;
// 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 of
+// non-ordinary section indexes are mapped to SHN_UNDEF. VERSION is
// the version of SYM.
template<int size, bool big_endian>
unsigned int orig_st_shndx,
Object* object, const char* version)
{
- if (object->target()->has_resolve())
+ if (parameters->target().has_resolve())
{
Sized_target<size, big_endian>* sized_target;
- sized_target = object->sized_target<size, big_endian>();
+ sized_target = parameters->sized_target<size, big_endian>();
sized_target->resolve(to, sym, object, version);
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))
+ {
+ // A dynamic object cannot reference a hidden or internal symbol
+ // defined in another object.
+ gold_warning(_("%s symbol '%s' in %s is referenced by DSO %s"),
+ (to->visibility() == elfcpp::STV_HIDDEN
+ ? "hidden"
+ : "internal"),
+ to->demangled_name().c_str(),
+ to->object()->name().c_str(),
+ object->name().c_str());
+ return;
+ }
else
{
// Record that we've seen this symbol in a dynamic object.
to->set_in_dyn();
}
- unsigned int frombits = symbol_to_bits(sym.get_st_bind(),
- object->is_dynamic(),
- st_shndx, is_ordinary,
- sym.get_st_type());
-
- bool adjust_common_sizes;
- if (Symbol_table::should_override(to, frombits, object,
- &adjust_common_sizes))
- {
- typename Sized_symbol<size>::Size_type tosize = to->symsize();
-
- this->override(to, sym, st_shndx, is_ordinary, object, version);
+ // 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)
+ to->set_in_real_elf();
- if (adjust_common_sizes && tosize > to->symsize())
- to->set_symsize(tosize);
- }
- else
+ // If we're processing replacement files, allow new symbols to override
+ // the placeholders from the plugin objects.
+ if (to->source() == Symbol::FROM_OBJECT)
{
- if (adjust_common_sizes && sym.get_st_size() > to->symsize())
- to->set_symsize(sym.get_st_size());
+ Pluginobj* obj = to->object()->pluginobj();
+ if (obj != NULL
+ && parameters->options().plugins()->in_replacement_phase())
+ {
+ this->override(to, sym, st_shndx, is_ordinary, object, version);
+ return;
+ }
}
// 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.)
+ // 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.)
bool to_is_ordinary;
if (parameters->options().detect_odr_violations()
- && sym.get_st_bind() == elfcpp::STB_WEAK
- && to->binding() == elfcpp::STB_WEAK
+ && (sym.get_st_bind() == elfcpp::STB_WEAK
+ || to->binding() == elfcpp::STB_WEAK)
&& orig_st_shndx != elfcpp::SHN_UNDEF
&& to->shndx(&to_is_ordinary) != elfcpp::SHN_UNDEF
&& to_is_ordinary
this->candidate_odr_violations_[to->name()].insert(fromloc);
this->candidate_odr_violations_[to->name()].insert(toloc);
}
+
+ unsigned int frombits = symbol_to_bits(sym.get_st_bind(),
+ object->is_dynamic(),
+ st_shndx, is_ordinary,
+ sym.get_st_type());
+
+ bool adjust_common_sizes;
+ typename Sized_symbol<size>::Size_type tosize = to->symsize();
+ if (Symbol_table::should_override(to, frombits, OBJECT, object,
+ &adjust_common_sizes))
+ {
+ this->override(to, sym, st_shndx, is_ordinary, object, version);
+ if (adjust_common_sizes && tosize > to->symsize())
+ to->set_symsize(tosize);
+ }
+ else
+ {
+ if (adjust_common_sizes && sym.get_st_size() > tosize)
+ to->set_symsize(sym.get_st_size());
+ // The ELF ABI says that even for a reference to a symbol we
+ // merge the visibility.
+ to->override_visibility(sym.get_st_visibility());
+ }
+
+ 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);
+ }
}
// Handle the core of symbol resolution. This is called with the
bool
Symbol_table::should_override(const Symbol* to, unsigned int frombits,
- Object* object, bool* adjust_common_sizes)
+ Defined defined, Object* object,
+ bool* adjust_common_sizes)
{
*adjust_common_sizes = false;
// --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->just_symbols())
+ || (object != NULL && object->just_symbols()))
return false;
- // 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")));
+ if (!parameters->options().muldefs())
+ Symbol_table::report_resolve_problem(true,
+ _("multiple definition of '%s'"),
+ to, defined, object);
return false;
case WEAK_DEF * 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, version a
- // warning.
+ // 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 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.
+ // 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 DEF * 16 + COMMON:
// A common symbol does not override a definition.
+ 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:
}
}
+// 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:
+ 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);
+}
+
// 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)
+Symbol_table::should_override_with_special(const Symbol* to, Defined defined)
{
bool adjust_common_sizes;
unsigned int frombits = global_flag | regular_flag | def_flag;
- bool ret = Symbol_table::should_override(to, frombits, NULL,
+ bool ret = Symbol_table::should_override(to, frombits, defined, NULL,
&adjust_common_sizes);
gold_assert(!adjust_common_sizes);
return ret;
break;
}
- if (from->version_ != NULL && this->version_ != from->version_)
- {
- gold_assert(this->version_ == NULL);
- this->version_ = from->version_;
- }
-
+ this->override_version(from->version_);
this->type_ = from->type_;
this->binding_ = from->binding_;
- this->visibility_ = from->visibility_;
+ this->override_visibility(from->visibility_);
this->nonvis_ = from->nonvis_;
// Special symbols are always considered to be regular symbols.
// 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_plt_offset_);
+ gold_assert(!from->has_plt_offset());
gold_assert(!from->has_warning_);
gold_assert(!from->is_copied_from_dynobj_);
gold_assert(!from->is_forced_local_);
}
while (ssym != tosym);
}
- if (tosym->binding() == elfcpp::STB_LOCAL)
+ 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);
}
// script to restrict this to only the ones needed for implemented
// targets.
-#ifdef HAVE_TARGET_32_LITTLE
+// 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, false>(
unsigned int orig_st_shndx,
Object* object,
const char* version);
-#endif
-#ifdef HAVE_TARGET_32_BIG
template
void
Symbol_table::resolve<32, true>(
const char* version);
#endif
-#ifdef HAVE_TARGET_64_LITTLE
+#if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
template
void
Symbol_table::resolve<64, false>(
unsigned int orig_st_shndx,
Object* object,
const char* version);
-#endif
-#ifdef HAVE_TARGET_64_BIG
template
void
Symbol_table::resolve<64, true>(