daily update
[external/binutils.git] / gold / symtab.cc
index f9bbcc0..30e7d10 100644 (file)
@@ -1,6 +1,6 @@
 // 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.
@@ -30,6 +30,7 @@
 #include <utility>
 #include "demangle.h"
 
+#include "gc.h"
 #include "object.h"
 #include "dwarf_reader.h"
 #include "dynobj.h"
@@ -37,6 +38,8 @@
 #include "target.h"
 #include "workqueue.h"
 #include "symtab.h"
+#include "demangle.h"   // needed for --dynamic-list-cpp-new
+#include "plugin.h"
 
 namespace gold
 {
@@ -73,6 +76,7 @@ Symbol::init_fields(const char* name, const char* version,
   this->is_copied_from_dynobj_ = false;
   this->is_forced_local_ = false;
   this->is_ordinary_shndx_ = false;
+  this->in_real_elf_ = false;
 }
 
 // Return the demangled version of the symbol's name, but only
@@ -117,6 +121,7 @@ Symbol::init_base_object(const char* name, const char* version, Object* object,
   this->source_ = FROM_OBJECT;
   this->in_reg_ = !object->is_dynamic();
   this->in_dyn_ = object->is_dynamic();
+  this->in_real_elf_ = object->pluginobj() == NULL;
 }
 
 // Initialize the fields in the base class Symbol for a symbol defined
@@ -133,6 +138,7 @@ Symbol::init_base_output_data(const char* name, const char* version,
   this->u_.in_output_data.offset_is_from_end = offset_is_from_end;
   this->source_ = IN_OUTPUT_DATA;
   this->in_reg_ = true;
+  this->in_real_elf_ = true;
 }
 
 // Initialize the fields in the base class Symbol for a symbol defined
@@ -150,6 +156,7 @@ Symbol::init_base_output_segment(const char* name, const char* version,
   this->u_.in_output_segment.offset_base = offset_base;
   this->source_ = IN_OUTPUT_SEGMENT;
   this->in_reg_ = true;
+  this->in_real_elf_ = true;
 }
 
 // Initialize the fields in the base class Symbol for a symbol defined
@@ -163,6 +170,7 @@ Symbol::init_base_constant(const char* name, const char* version,
   this->init_fields(name, version, type, binding, visibility, nonvis);
   this->source_ = IS_CONSTANT;
   this->in_reg_ = true;
+  this->in_real_elf_ = true;
 }
 
 // Initialize the fields in the base class Symbol for an undefined
@@ -174,8 +182,10 @@ Symbol::init_base_undefined(const char* name, const char* version,
                            elfcpp::STV visibility, unsigned char nonvis)
 {
   this->init_fields(name, version, type, binding, visibility, nonvis);
+  this->dynsym_index_ = -1U;
   this->source_ = IS_UNDEFINED;
   this->in_reg_ = true;
+  this->in_real_elf_ = true;
 }
 
 // Allocate a common symbol in the base.
@@ -280,6 +290,9 @@ Sized_symbol<size>::allocate_common(Output_data* od, Value_type value)
   this->value_ = value;
 }
 
+// The ""'s around str ensure str is a string literal, so sizeof works.
+#define strprefix(var, str)   (strncmp(var, str, sizeof("" str "") - 1) == 0)
+
 // Return true if this symbol should be added to the dynamic symbol
 // table.
 
@@ -290,10 +303,68 @@ Symbol::should_add_dynsym_entry() const
   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;
 
+  // If the symbol was forced dynamic in a --dynamic-list file, add it.
+  if (parameters->options().in_dynamic_list(this->name()))
+    return true;
+
+  // If dynamic-list-data was specified, add any STT_OBJECT.
+  if (parameters->options().dynamic_list_data()
+      && !this->is_from_dynobj()
+      && this->type() == elfcpp::STT_OBJECT)
+    return true;
+
+  // If --dynamic-list-cpp-new was specified, add any new/delete symbol.
+  // If --dynamic-list-cpp-typeinfo was specified, add any typeinfo symbols.
+  if ((parameters->options().dynamic_list_cpp_new()
+       || parameters->options().dynamic_list_cpp_typeinfo())
+      && !this->is_from_dynobj())
+    {
+      // TODO(csilvers): We could probably figure out if we're an operator
+      //                 new/delete or typeinfo without the need to demangle.
+      char* demangled_name = cplus_demangle(this->name(),
+                                            DMGL_ANSI | DMGL_PARAMS);
+      if (demangled_name == NULL)
+        {
+          // Not a C++ symbol, so it can't satisfy these flags
+        }
+      else if (parameters->options().dynamic_list_cpp_new()
+               && (strprefix(demangled_name, "operator new")
+                   || strprefix(demangled_name, "operator delete")))
+        {
+          free(demangled_name);
+          return true;
+        }
+      else if (parameters->options().dynamic_list_cpp_typeinfo()
+               && (strprefix(demangled_name, "typeinfo name for")
+                   || strprefix(demangled_name, "typeinfo for")))
+        {
+          free(demangled_name);
+          return true;
+        }
+      else
+        free(demangled_name);
+    }
+
   // If exporting all symbols or building a shared library,
   // and the symbol is defined in a regular object and is
   // externally visible, we need to add it.
@@ -356,6 +427,7 @@ Symbol::output_section() const
        if (shndx != elfcpp::SHN_UNDEF && this->is_ordinary_shndx_)
          {
            gold_assert(!this->u_.from_object.object->is_dynamic());
+           gold_assert(this->u_.from_object.object->pluginobj() == NULL);
            Relobj* relobj = static_cast<Relobj*>(this->u_.from_object.object);
            return relobj->output_section(shndx);
          }
@@ -406,7 +478,7 @@ Symbol_table::Symbol_table(unsigned int count,
                            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);
 }
@@ -433,6 +505,72 @@ Symbol_table::Symbol_table_eq::operator()(const Symbol_table_key& k1,
   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
@@ -489,8 +627,7 @@ Symbol_table::lookup(const char* name, const char* version) const
 
 template<int size, bool big_endian>
 void
-Symbol_table::resolve(Sized_symbol<size>* to, const Sized_symbol<size>* from,
-                     const char* version)
+Symbol_table::resolve(Sized_symbol<size>* to, const Sized_symbol<size>* from)
 {
   unsigned char buf[elfcpp::Elf_sizes<size>::sym_size];
   elfcpp::Sym_write<size, big_endian> esym(buf);
@@ -502,14 +639,17 @@ Symbol_table::resolve(Sized_symbol<size>* to, const Sized_symbol<size>* from,
   bool is_ordinary;
   unsigned int shndx = from->shndx(&is_ordinary);
   this->resolve(to, esym.sym(), shndx, is_ordinary, shndx, from->object(),
-               version);
+               from->version());
   if (from->in_reg())
     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)
@@ -573,6 +713,82 @@ Symbol_table::wrap_symbol(Object* object, const char* name,
   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
@@ -678,71 +894,12 @@ Symbol_table::add_from_object(Object* object,
 
       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, version);
-                 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
     {
@@ -760,6 +917,8 @@ Symbol_table::add_from_object(Object* object,
 
          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
@@ -802,6 +961,9 @@ Symbol_table::add_from_object(Object* object,
              insdef.first->second = ret;
            }
        }
+
+      if (def)
+       ret->set_is_default();
     }
 
   // Record every time we see a new undefined symbol, to speed up
@@ -819,8 +981,15 @@ Symbol_table::add_from_object(Object* object,
        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;
 }
 
@@ -835,8 +1004,11 @@ Symbol_table::add_from_relobj(
     size_t symndx_offset,
     const char* sym_names,
     size_t sym_name_size,
-    typename Sized_relobj<size, big_endian>::Symbols* sympointers)
+    typename Sized_relobj<size, big_endian>::Symbols* sympointers,
+    size_t *defined)
 {
+  *defined = 0;
+
   gold_assert(size == relobj->target()->get_size());
   gold_assert(size == parameters->target().get_size());
 
@@ -847,6 +1019,8 @@ Symbol_table::add_from_relobj(
   const unsigned char* p = syms;
   for (size_t i = 0; i < count; ++i, p += sym_size)
     {
+      (*sympointers)[i] = NULL;
+
       elfcpp::Sym<size, big_endian> sym(p);
 
       unsigned int st_name = sym.get_st_name();
@@ -867,6 +1041,9 @@ Symbol_table::add_from_relobj(
       if (!is_ordinary)
        orig_st_shndx = elfcpp::SHN_UNDEF;
 
+      if (st_shndx != elfcpp::SHN_UNDEF)
+       ++*defined;
+
       // A symbol defined in a section which we are not including must
       // be treated as an undefined symbol.
       if (st_shndx != elfcpp::SHN_UNDEF
@@ -878,6 +1055,7 @@ Symbol_table::add_from_relobj(
       // name from the version name.  If there are two '@' characters,
       // this is the default version.
       const char* ver = strchr(name, '@');
+      Stringpool::Key ver_key = 0;
       int namelen = 0;
       // DEF: is the version default?  LOCAL: is the symbol forced local?
       bool def = false;
@@ -893,26 +1071,37 @@ Symbol_table::add_from_relobj(
              def = true;
              ++ver;
            }
+         ver = this->namepool_.add(ver, true, &ver_key);
         }
       // We don't want to assign a version to an undefined symbol,
       // even if it is listed in the version script.  FIXME: What
       // about a common symbol?
-      else if (!version_script_.empty()
-              && st_shndx != elfcpp::SHN_UNDEF)
-        {
-          // The symbol name did not have a version, but
-          // the version script may assign a version anyway.
-          namelen = strlen(name);
-          def = true;
-          // Check the global: entries from the version script.
-          const std::string& version =
-              version_script_.get_symbol_version(name);
-          if (!version.empty())
-            ver = version.c_str();
-          // Check the local: entries from the version script
-          if (version_script_.symbol_is_local(name))
-            local = true;
-        }
+      else
+       {
+         namelen = strlen(name);
+         if (!this->version_script_.empty()
+             && st_shndx != elfcpp::SHN_UNDEF)
+           {
+             // The symbol name did not have a version, but the
+             // version script may assign a version anyway.
+             std::string version;
+             if (this->version_script_.get_symbol_version(name, &version))
+               {
+                 // The version can be empty if the version script is
+                 // only used to force some symbols to be local.
+                 if (!version.empty())
+                   {
+                     ver = this->namepool_.add_with_length(version.c_str(),
+                                                           version.length(),
+                                                           true,
+                                                           &ver_key);
+                     def = true;
+                   }
+               }
+             else if (this->version_script_.symbol_is_local(name))
+               local = true;
+           }
+       }
 
       elfcpp::Sym<size, big_endian>* psym = &sym;
       unsigned char symbuf[sym_size];
@@ -937,34 +1126,90 @@ Symbol_table::add_from_relobj(
          psym = &sym2;
        }
 
-      Sized_symbol<size>* res;
-      if (ver == NULL)
-       {
-         Stringpool::Key name_key;
-         name = this->namepool_.add(name, true, &name_key);
-         res = this->add_from_object(relobj, name, name_key, NULL, 0,
-                                     false, *psym, st_shndx, is_ordinary,
-                                     orig_st_shndx);
-          if (local)
-           this->force_local(res);
-       }
-      else
-       {
-         Stringpool::Key name_key;
-         name = this->namepool_.add_with_length(name, namelen, true,
-                                                &name_key);
-         Stringpool::Key ver_key;
-         ver = this->namepool_.add(ver, true, &ver_key);
+      Stringpool::Key name_key;
+      name = this->namepool_.add_with_length(name, namelen, true,
+                                            &name_key);
 
-         res = this->add_from_object(relobj, name, name_key, ver, ver_key,
-                                     def, *psym, st_shndx, is_ordinary,
-                                     orig_st_shndx);
-       }
+      Sized_symbol<size>* res;
+      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);
 
       (*sympointers)[i] = res;
     }
 }
 
+// Add a symbol from a plugin-claimed file.
+
+template<int size, bool big_endian>
+Symbol*
+Symbol_table::add_from_pluginobj(
+    Sized_pluginobj<size, big_endian>* obj,
+    const char* name,
+    const char* ver,
+    elfcpp::Sym<size, big_endian>* sym)
+{
+  unsigned int st_shndx = sym->get_st_shndx();
+
+  Stringpool::Key ver_key = 0;
+  bool def = false;
+  bool local = false;
+
+  if (ver != NULL)
+    {
+      ver = this->namepool_.add(ver, true, &ver_key);
+    }
+  // We don't want to assign a version to an undefined symbol,
+  // even if it is listed in the version script.  FIXME: What
+  // about a common symbol?
+  else
+    {
+      if (!this->version_script_.empty()
+          && st_shndx != elfcpp::SHN_UNDEF)
+        {
+          // The symbol name did not have a version, but the
+          // version script may assign a version anyway.
+          std::string version;
+          if (this->version_script_.get_symbol_version(name, &version))
+            {
+              // The version can be empty if the version script is
+              // only used to force some symbols to be local.
+              if (!version.empty())
+                {
+                  ver = this->namepool_.add_with_length(version.c_str(),
+                                                        version.length(),
+                                                        true,
+                                                        &ver_key);
+                  def = true;
+                }
+            }
+          else if (this->version_script_.symbol_is_local(name))
+            local = true;
+        }
+    }
+
+  Stringpool::Key name_key;
+  name = this->namepool_.add(name, true, &name_key);
+
+  Sized_symbol<size>* res;
+  res = this->add_from_object(obj, name, name_key, ver, ver_key,
+                             def, *sym, st_shndx, true, st_shndx);
+
+  if (local)
+    this->force_local(res);
+
+  return res;
+}
+
 // Add all the symbols in a dynamic object to the hash table.
 
 template<int size, bool big_endian>
@@ -977,8 +1222,12 @@ Symbol_table::add_from_dynobj(
     size_t sym_name_size,
     const unsigned char* versym,
     size_t versym_size,
-    const std::vector<const char*>* version_map)
+    const std::vector<const char*>* version_map,
+    typename Sized_relobj<size, big_endian>::Symbols* sympointers,
+    size_t* defined)
 {
+  *defined = 0;
+
   gold_assert(size == dynobj->target()->get_size());
   gold_assert(size == parameters->target().get_size());
 
@@ -1012,6 +1261,9 @@ Symbol_table::add_from_dynobj(
     {
       elfcpp::Sym<size, big_endian> sym(p);
 
+      if (sympointers != NULL)
+       (*sympointers)[i] = NULL;
+
       // Ignore symbols with local binding or that have
       // internal or hidden visibility.
       if (sym.get_st_bind() == elfcpp::STB_LOCAL
@@ -1047,6 +1299,9 @@ Symbol_table::add_from_dynobj(
       unsigned int st_shndx = dynobj->adjust_sym_shndx(i, psym->get_st_shndx(),
                                                       &is_ordinary);
 
+      if (st_shndx != elfcpp::SHN_UNDEF)
+       ++*defined;
+
       Sized_symbol<size>* res;
 
       if (versym == NULL)
@@ -1142,6 +1397,9 @@ Symbol_table::add_from_dynobj(
          && res->source() == Symbol::FROM_OBJECT
          && res->object() == dynobj)
        object_symbols.push_back(res);
+
+      if (sympointers != NULL)
+       (*sympointers)[i] = res;
     }
 
   this->record_weak_aliases(&object_symbols);
@@ -1235,36 +1493,55 @@ Symbol_table::record_weak_aliases(std::vector<Sized_symbol<size>*>* symbols)
 // 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)
     {
-      const std::string& v(this->version_script_.get_symbol_version(*pname));
-      if (!v.empty())
-       *pversion = v.c_str();
+      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
     {
@@ -1282,19 +1559,56 @@ Symbol_table::define_special_symbol(const char** pname, const char** pversion,
                                                          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;
+               }
+           }
        }
     }
 
@@ -1318,6 +1632,9 @@ Symbol_table::define_special_symbol(const char** pname, const char** pversion,
   else
     gold_assert(oldsym != NULL);
 
+  if (add_def_to_table)
+    add_def_loc->second = sym;
+
   *poldsym = this->get_sized_symbol<size>(oldsym);
 
   return sym;
@@ -1385,12 +1702,14 @@ Symbol_table::do_define_in_output_data(
 {
   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
@@ -1399,7 +1718,8 @@ Symbol_table::do_define_in_output_data(
     {
 #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
@@ -1423,8 +1743,14 @@ Symbol_table::do_define_in_output_data(
 
   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.
@@ -1486,12 +1812,14 @@ Symbol_table::do_define_in_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
@@ -1500,7 +1828,8 @@ Symbol_table::do_define_in_output_segment(
     {
 #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
@@ -1524,8 +1853,14 @@ Symbol_table::do_define_in_output_segment(
 
   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
@@ -1587,12 +1922,14 @@ Symbol_table::do_define_as_constant(
 {
   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
@@ -1601,7 +1938,8 @@ Symbol_table::do_define_as_constant(
     {
 #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
@@ -1631,8 +1969,14 @@ Symbol_table::do_define_as_constant(
 
   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.
@@ -1796,11 +2140,13 @@ Symbol_table::do_add_undefined_symbols_from_command_line()
 
       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
@@ -1809,7 +2155,8 @@ Symbol_table::do_add_undefined_symbols_from_command_line()
        {
 #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
@@ -2019,6 +2366,11 @@ Symbol_table::sized_finalize_symbol(Symbol* unsized_sym)
            value = 0;
            shndx = elfcpp::SHN_UNDEF;
          }
+       else if (symobj->pluginobj() != NULL)
+         {
+           value = 0;
+           shndx = elfcpp::SHN_UNDEF;
+         }
        else if (shndx == elfcpp::SHN_UNDEF)
          value = 0;
        else if (!is_ordinary
@@ -2032,16 +2384,28 @@ Symbol_table::sized_finalize_symbol(Symbol* unsized_sym)
            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;
              }
 
             uint64_t secoff64 = relobj->output_section_offset(shndx);
-            Value_type secoff = convert_types<Value_type, uint64_t>(secoff64);
-           if (sym->type() == elfcpp::STT_TLS)
-             value = sym->value() + os->tls_offset() + secoff;
-           else
-             value = sym->value() + os->address() + secoff;
+            if (secoff64 == -1ULL)
+              {
+                // The section needs special handling (e.g., a merge section).
+               value = os->output_address(relobj, shndx, sym->value());
+             }
+            else
+              {
+                Value_type secoff =
+                  convert_types<Value_type, uint64_t>(secoff64);
+               if (sym->type() == elfcpp::STT_TLS)
+                 value = sym->value() + os->tls_offset() + secoff;
+               else
+                 value = sym->value() + os->address() + secoff;
+             }
          }
       }
       break;
@@ -2111,8 +2475,7 @@ Symbol_table::sized_finalize_symbol(Symbol* unsized_sym)
 // 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,
@@ -2122,29 +2485,25 @@ Symbol_table::write_globals(const Input_objects* input_objects,
     {
 #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
@@ -2157,8 +2516,7 @@ Symbol_table::write_globals(const Input_objects* input_objects,
 
 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,
@@ -2194,7 +2552,7 @@ Symbol_table::sized_write_globals(const Input_objects* input_objects,
       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;
@@ -2237,6 +2595,8 @@ Symbol_table::sized_write_globals(const Input_objects* input_objects,
                      dynsym_value = target.dynsym_value(sym);
                    shndx = elfcpp::SHN_UNDEF;
                  }
+               else if (symobj->pluginobj() != NULL)
+                 shndx = elfcpp::SHN_UNDEF;
                else if (in_shndx == elfcpp::SHN_UNDEF
                         || (!is_ordinary
                             && (in_shndx == elfcpp::SHN_ABS
@@ -2334,8 +2694,11 @@ Symbol_table::sized_write_symbol(
   elfcpp::Sym_write<size, big_endian> osym(p);
   osym.put_st_name(pool->get_offset(sym->name()));
   osym.put_st_value(value);
-  // Use a symbol size of zero for undefined symbols.
-  osym.put_st_size(shndx == elfcpp::SHN_UNDEF ? 0 : sym->symsize());
+  // Use a symbol size of zero for undefined symbols from shared libraries.
+  if (shndx == elfcpp::SHN_UNDEF && sym->is_from_dynobj())
+    osym.put_st_size(0);
+  else
+    osym.put_st_size(sym->symsize());
   // A version script may have overridden the default binding.
   if (sym->is_forced_local())
     osym.put_st_info(elfcpp::elf_st_info(elfcpp::STB_LOCAL, sym->type()));
@@ -2354,16 +2717,13 @@ Symbol_table::sized_write_symbol(
 // 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
@@ -2372,22 +2732,12 @@ Symbol_table::warn_about_undefined_dynobj_symbol(
       && 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);
     }
 }
 
@@ -2445,7 +2795,10 @@ Symbol_table::sized_write_section_symbol(const Output_section* os,
 
   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));
@@ -2628,7 +2981,8 @@ Symbol_table::add_from_relobj<32, false>(
     size_t symndx_offset,
     const char* sym_names,
     size_t sym_name_size,
-    Sized_relobj<32, true>::Symbols* sympointers);
+    Sized_relobj<32, false>::Symbols* sympointers,
+    size_t* defined);
 #endif
 
 #ifdef HAVE_TARGET_32_BIG
@@ -2641,7 +2995,8 @@ Symbol_table::add_from_relobj<32, true>(
     size_t symndx_offset,
     const char* sym_names,
     size_t sym_name_size,
-    Sized_relobj<32, false>::Symbols* sympointers);
+    Sized_relobj<32, true>::Symbols* sympointers,
+    size_t* defined);
 #endif
 
 #ifdef HAVE_TARGET_64_LITTLE
@@ -2654,7 +3009,8 @@ Symbol_table::add_from_relobj<64, false>(
     size_t symndx_offset,
     const char* sym_names,
     size_t sym_name_size,
-    Sized_relobj<64, true>::Symbols* sympointers);
+    Sized_relobj<64, false>::Symbols* sympointers,
+    size_t* defined);
 #endif
 
 #ifdef HAVE_TARGET_64_BIG
@@ -2667,7 +3023,48 @@ Symbol_table::add_from_relobj<64, true>(
     size_t symndx_offset,
     const char* sym_names,
     size_t sym_name_size,
-    Sized_relobj<64, false>::Symbols* sympointers);
+    Sized_relobj<64, true>::Symbols* sympointers,
+    size_t* defined);
+#endif
+
+#ifdef HAVE_TARGET_32_LITTLE
+template
+Symbol*
+Symbol_table::add_from_pluginobj<32, false>(
+    Sized_pluginobj<32, false>* obj,
+    const char* name,
+    const char* ver,
+    elfcpp::Sym<32, false>* sym);
+#endif
+
+#ifdef HAVE_TARGET_32_BIG
+template
+Symbol*
+Symbol_table::add_from_pluginobj<32, true>(
+    Sized_pluginobj<32, true>* obj,
+    const char* name,
+    const char* ver,
+    elfcpp::Sym<32, true>* sym);
+#endif
+
+#ifdef HAVE_TARGET_64_LITTLE
+template
+Symbol*
+Symbol_table::add_from_pluginobj<64, false>(
+    Sized_pluginobj<64, false>* obj,
+    const char* name,
+    const char* ver,
+    elfcpp::Sym<64, false>* sym);
+#endif
+
+#ifdef HAVE_TARGET_64_BIG
+template
+Symbol*
+Symbol_table::add_from_pluginobj<64, true>(
+    Sized_pluginobj<64, true>* obj,
+    const char* name,
+    const char* ver,
+    elfcpp::Sym<64, true>* sym);
 #endif
 
 #ifdef HAVE_TARGET_32_LITTLE
@@ -2681,7 +3078,9 @@ Symbol_table::add_from_dynobj<32, false>(
     size_t sym_name_size,
     const unsigned char* versym,
     size_t versym_size,
-    const std::vector<const char*>* version_map);
+    const std::vector<const char*>* version_map,
+    Sized_relobj<32, false>::Symbols* sympointers,
+    size_t* defined);
 #endif
 
 #ifdef HAVE_TARGET_32_BIG
@@ -2695,7 +3094,9 @@ Symbol_table::add_from_dynobj<32, true>(
     size_t sym_name_size,
     const unsigned char* versym,
     size_t versym_size,
-    const std::vector<const char*>* version_map);
+    const std::vector<const char*>* version_map,
+    Sized_relobj<32, true>::Symbols* sympointers,
+    size_t* defined);
 #endif
 
 #ifdef HAVE_TARGET_64_LITTLE
@@ -2709,7 +3110,9 @@ Symbol_table::add_from_dynobj<64, false>(
     size_t sym_name_size,
     const unsigned char* versym,
     size_t versym_size,
-    const std::vector<const char*>* version_map);
+    const std::vector<const char*>* version_map,
+    Sized_relobj<64, false>::Symbols* sympointers,
+    size_t* defined);
 #endif
 
 #ifdef HAVE_TARGET_64_BIG
@@ -2723,7 +3126,9 @@ Symbol_table::add_from_dynobj<64, true>(
     size_t sym_name_size,
     const unsigned char* versym,
     size_t versym_size,
-    const std::vector<const char*>* version_map);
+    const std::vector<const char*>* version_map,
+    Sized_relobj<64, true>::Symbols* sympointers,
+    size_t* defined);
 #endif
 
 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)