2011-02-28 Michael Snyder <msnyder@vmware.com>
[deliverable/binutils-gdb.git] / gold / symtab.cc
index c2a811f19c0be84cb5b45b56ee6e176551a1dd9d..d4ac297792a9b4d9089fb7e34b5cc333dbdbb9e3 100644 (file)
@@ -1,6 +1,6 @@
 // symtab.cc -- the gold symbol table
 
-// Copyright 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
+// Copyright 2006, 2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
 // Written by Ian Lance Taylor <iant@google.com>.
 
 // This file is part of gold.
@@ -38,7 +38,7 @@
 #include "target.h"
 #include "workqueue.h"
 #include "symtab.h"
-#include "demangle.h"   // needed for --dynamic-list-cpp-new
+#include "script.h"
 #include "plugin.h"
 
 namespace gold
@@ -76,6 +76,8 @@ Symbol::init_fields(const char* name, const char* version,
   this->is_ordinary_shndx_ = false;
   this->in_real_elf_ = false;
   this->is_defined_in_discarded_section_ = false;
+  this->undef_binding_set_ = false;
+  this->undef_binding_weak_ = false;
 }
 
 // Return the demangled version of the symbol's name, but only
@@ -306,8 +308,13 @@ Sized_symbol<size>::allocate_common(Output_data* od, Value_type value)
 // table.
 
 inline bool
-Symbol::should_add_dynsym_entry() const
+Symbol::should_add_dynsym_entry(Symbol_table* symtab) const
 {
+  // If the symbol is only present on plugin files, the plugin decided we
+  // don't need it.
+  if (!this->in_real_elf())
+    return false;
+
   // If the symbol is used by a dynamic relocation, we need to add it.
   if (this->needs_dynsym_entry())
     return true;
@@ -324,7 +331,8 @@ Symbol::should_add_dynsym_entry() const
       bool is_ordinary;
       unsigned int shndx = this->shndx(&is_ordinary);
       if (is_ordinary && shndx != elfcpp::SHN_UNDEF
-          && !relobj->is_section_included(shndx))
+          && !relobj->is_section_included(shndx)
+          && !symtab->is_section_folded(relobj, shndx))
         return false;
     }
 
@@ -498,14 +506,6 @@ Symbol_table::~Symbol_table()
 {
 }
 
-// The hash function.  The key values are Stringpool keys.
-
-inline size_t
-Symbol_table::Symbol_table_hash::operator()(const Symbol_table_key& key) const
-{
-  return key.first ^ key.second;
-}
-
 // The symbol table key equality function.  This is called with
 // Stringpool keys.
 
@@ -527,7 +527,7 @@ Symbol_table::is_section_folded(Object* obj, unsigned int shndx) const
 // work list to avoid gc'ing them.
 
 void 
-Symbol_table::gc_mark_undef_symbols()
+Symbol_table::gc_mark_undef_symbols(Layout* layout)
 {
   for (options::String_set::const_iterator p =
         parameters->options().undefined_begin();
@@ -536,7 +536,7 @@ Symbol_table::gc_mark_undef_symbols()
     {
       const char* name = p->c_str();
       Symbol* sym = this->lookup(name);
-      gold_assert (sym != NULL);
+      gold_assert(sym != NULL);
       if (sym->source() == Symbol::FROM_OBJECT 
           && !sym->object()->is_dynamic())
         {
@@ -550,6 +550,27 @@ Symbol_table::gc_mark_undef_symbols()
             }
         }
     }
+
+  for (Script_options::referenced_const_iterator p =
+        layout->script_options()->referenced_begin();
+       p != layout->script_options()->referenced_end();
+       ++p)
+    {
+      Symbol* sym = this->lookup(p->c_str());
+      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
@@ -578,7 +599,7 @@ 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()); 
+      Relobjobj = static_cast<Relobj*>(sym->object()); 
       bool is_ordinary;
       unsigned int shndx = sym->shndx(&is_ordinary);
       if (is_ordinary && shndx != elfcpp::SHN_UNDEF)
@@ -839,9 +860,9 @@ Symbol_table::define_default_version(Sized_symbol<size>* sym,
 template<int size, bool big_endian>
 Sized_symbol<size>*
 Symbol_table::add_from_object(Object* object,
-                             const char *name,
+                             const charname,
                              Stringpool::Key name_key,
-                             const char *version,
+                             const charversion,
                              Stringpool::Key version_key,
                              bool is_default_version,
                              const elfcpp::Sym<size, big_endian>& sym,
@@ -986,7 +1007,11 @@ Symbol_table::add_from_object(Object* object,
   // Record every time we see a new undefined symbol, to speed up
   // archive groups.
   if (!was_undefined && ret->is_undefined())
-    ++this->saw_undefined_;
+    {
+      ++this->saw_undefined_;
+      if (parameters->options().has_plugins())
+       parameters->options().plugins()->new_undefined_symbol(ret);
+    }
 
   // Keep track of common symbols, to speed up common symbol
   // allocation.
@@ -1029,7 +1054,7 @@ Symbol_table::add_from_relobj(
     const char* sym_names,
     size_t sym_name_size,
     typename Sized_relobj<size, big_endian>::Symbols* sympointers,
-    size_t *defined)
+    size_tdefined)
 {
   *defined = 0;
 
@@ -1072,7 +1097,8 @@ Symbol_table::add_from_relobj(
       bool is_defined_in_discarded_section = false;
       if (st_shndx != elfcpp::SHN_UNDEF
          && is_ordinary
-         && !relobj->is_section_included(st_shndx))
+         && !relobj->is_section_included(st_shndx)
+          && !this->is_section_folded(relobj, st_shndx))
        {
          st_shndx = elfcpp::SHN_UNDEF;
          is_defined_in_discarded_section = true;
@@ -1556,7 +1582,7 @@ Sized_symbol<size>*
 Symbol_table::define_special_symbol(const char** pname, const char** pversion,
                                    bool only_if_ref,
                                     Sized_symbol<size>** poldsym,
-                                   bool *resolve_oldsym)
+                                   boolresolve_oldsym)
 {
   *resolve_oldsym = false;
 
@@ -2159,14 +2185,15 @@ Symbol_table::get_copy_source(const Symbol* sym) const
 // Add any undefined symbols named on the command line.
 
 void
-Symbol_table::add_undefined_symbols_from_command_line()
+Symbol_table::add_undefined_symbols_from_command_line(Layout* layout)
 {
-  if (parameters->options().any_undefined())
+  if (parameters->options().any_undefined()
+      || layout->script_options()->any_unreferenced())
     {
       if (parameters->target().get_size() == 32)
        {
 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
-         this->do_add_undefined_symbols_from_command_line<32>();
+         this->do_add_undefined_symbols_from_command_line<32>(layout);
 #else
          gold_unreachable();
 #endif
@@ -2174,7 +2201,7 @@ Symbol_table::add_undefined_symbols_from_command_line()
       else if (parameters->target().get_size() == 64)
        {
 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
-         this->do_add_undefined_symbols_from_command_line<64>();
+         this->do_add_undefined_symbols_from_command_line<64>(layout);
 #else
          gold_unreachable();
 #endif
@@ -2186,50 +2213,59 @@ Symbol_table::add_undefined_symbols_from_command_line()
 
 template<int size>
 void
-Symbol_table::do_add_undefined_symbols_from_command_line()
+Symbol_table::do_add_undefined_symbols_from_command_line(Layout* layout)
 {
   for (options::String_set::const_iterator p =
         parameters->options().undefined_begin();
        p != parameters->options().undefined_end();
        ++p)
-    {
-      const char* name = p->c_str();
+    this->add_undefined_symbol_from_command_line<size>(p->c_str());
 
-      if (this->lookup(name) != NULL)
-       continue;
+  for (Script_options::referenced_const_iterator p =
+        layout->script_options()->referenced_begin();
+       p != layout->script_options()->referenced_end();
+       ++p)
+    this->add_undefined_symbol_from_command_line<size>(p->c_str());
+}
 
-      const char* version = NULL;
+template<int size>
+void
+Symbol_table::add_undefined_symbol_from_command_line(const char* name)
+{
+  if (this->lookup(name) != NULL)
+    return;
 
-      Sized_symbol<size>* sym;
-      Sized_symbol<size>* oldsym;
-      bool resolve_oldsym;
-      if (parameters->target().is_big_endian())
-       {
+  const char* version = NULL;
+
+  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,
-                                                       &resolve_oldsym);
+      sym = this->define_special_symbol<size, true>(&name, &version,
+                                                   false, &oldsym,
+                                                   &resolve_oldsym);
 #else
-         gold_unreachable();
+      gold_unreachable();
 #endif
-       }
-      else
-       {
+    }
+  else
+    {
 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
-         sym = this->define_special_symbol<size, false>(&name, &version,
-                                                        false, &oldsym,
-                                                        &resolve_oldsym);
+      sym = this->define_special_symbol<size, false>(&name, &version,
+                                                    false, &oldsym,
+                                                    &resolve_oldsym);
 #else
-         gold_unreachable();
+      gold_unreachable();
 #endif
-       }
+    }
 
-      gold_assert(oldsym == NULL);
+  gold_assert(oldsym == NULL);
 
-      sym->init_undefined(name, version, elfcpp::STT_NOTYPE, elfcpp::STB_GLOBAL,
-                         elfcpp::STV_DEFAULT, 0);
-      ++this->saw_undefined_;
-    }
+  sym->init_undefined(name, version, elfcpp::STT_NOTYPE, elfcpp::STB_GLOBAL,
+                     elfcpp::STV_DEFAULT, 0);
+  ++this->saw_undefined_;
 }
 
 // Set the dynamic symbol indexes.  INDEX is the index of the first
@@ -2253,7 +2289,7 @@ Symbol_table::set_dynsym_indexes(unsigned int index,
       // some symbols appear more than once in the symbol table, with
       // and without a version.
 
-      if (!sym->should_add_dynsym_entry())
+      if (!sym->should_add_dynsym_entry(this))
        sym->set_dynsym_index(-1U);
       else if (!sym->has_dynsym_index())
        {
@@ -2289,7 +2325,7 @@ Symbol_table::set_dynsym_indexes(unsigned int index,
 off_t
 Symbol_table::finalize(off_t off, off_t dynoff, size_t dyn_global_index,
                       size_t dyncount, Stringpool* pool,
-                      unsigned int *plocal_symcount)
+                      unsigned intplocal_symcount)
 {
   off_t ret;
 
@@ -2562,6 +2598,15 @@ Symbol_table::sized_finalize_symbol(Symbol* unsized_sym)
       return false;
     }
 
+  // If the symbol is only present on plugin files, the plugin decided we
+  // don't need it.
+  if (!sym->in_real_elf())
+    {
+      gold_assert(!sym->has_symtab_index());
+      sym->set_symtab_index(-1U);
+      return false;
+    }
+
   // Compute final symbol value.
   Compute_final_value_status status;
   Value_type value = this->compute_final_value(sym, &status);
@@ -2695,6 +2740,7 @@ Symbol_table::sized_write_globals(const Stringpool* sympool,
       unsigned int shndx;
       typename elfcpp::Elf_types<size>::Elf_Addr sym_value = sym->value();
       typename elfcpp::Elf_types<size>::Elf_Addr dynsym_value = sym_value;
+      elfcpp::STB binding = sym->binding();
       switch (sym->source())
        {
        case Symbol::FROM_OBJECT:
@@ -2718,6 +2764,10 @@ Symbol_table::sized_write_globals(const Stringpool* sympool,
                    if (sym->needs_dynsym_value())
                      dynsym_value = target.dynsym_value(sym);
                    shndx = elfcpp::SHN_UNDEF;
+                   if (sym->is_undef_binding_weak())
+                     binding = elfcpp::STB_WEAK;
+                   else
+                     binding = elfcpp::STB_GLOBAL;
                  }
                else if (symobj->pluginobj() != NULL)
                  shndx = elfcpp::SHN_UNDEF;
@@ -2798,7 +2848,7 @@ Symbol_table::sized_write_globals(const Stringpool* sympool,
          gold_assert(sym_index < output_count);
          unsigned char* ps = psyms + (sym_index * sym_size);
          this->sized_write_symbol<size, big_endian>(sym, sym_value, shndx,
-                                                    sympool, ps);
+                                                    binding, sympool, ps);
        }
 
       if (dynsym_index != -1U)
@@ -2807,7 +2857,7 @@ Symbol_table::sized_write_globals(const Stringpool* sympool,
          gold_assert(dynsym_index < dynamic_count);
          unsigned char* pd = dynamic_view + (dynsym_index * sym_size);
          this->sized_write_symbol<size, big_endian>(sym, dynsym_value, shndx,
-                                                    dynpool, pd);
+                                                    binding, dynpool, pd);
        }
     }
 
@@ -2825,6 +2875,7 @@ Symbol_table::sized_write_symbol(
     Sized_symbol<size>* sym,
     typename elfcpp::Elf_types<size>::Elf_Addr value,
     unsigned int shndx,
+    elfcpp::STB binding,
     const Stringpool* pool,
     unsigned char* p) const
 {
@@ -2845,7 +2896,7 @@ Symbol_table::sized_write_symbol(
   if (sym->is_forced_local())
     osym.put_st_info(elfcpp::elf_st_info(elfcpp::STB_LOCAL, type));
   else
-    osym.put_st_info(elfcpp::elf_st_info(sym->binding(), type));
+    osym.put_st_info(elfcpp::elf_st_info(binding, type));
   osym.put_st_other(elfcpp::elf_st_other(sym->visibility(), sym->nonvis()));
   osym.put_st_shndx(shndx);
 }
@@ -2886,7 +2937,7 @@ Symbol_table::warn_about_undefined_dynobj_symbol(Symbol* sym) const
 // Write out a section symbol.  Return the update offset.
 
 void
-Symbol_table::write_section_symbol(const Output_section *os,
+Symbol_table::write_section_symbol(const Output_sectionos,
                                   Output_symtab_xindex* symtab_xindex,
                                   Output_file* of,
                                   off_t offset) const
@@ -2975,11 +3026,12 @@ Symbol_table::print_stats() const
 // We check for ODR violations by looking for symbols with the same
 // name for which the debugging information reports that they were
 // defined in different source locations.  When comparing the source
-// location, we consider instances with the same base filename and
-// line number to be the same.  This is because different object
-// files/shared libraries can include the same header file using
-// different paths, and we don't want to report an ODR violation in
-// that case.
+// location, we consider instances with the same base filename to be
+// the same.  This is because different object files/shared libraries
+// can include the same header file using different paths, and
+// different optimization settings can make the line number appear to
+// be a couple lines off, and we don't want to report an ODR violation
+// in those cases.
 
 // This struct is used to compare line information, as returned by
 // Dwarf_line_info::one_addr2line.  It implements a < comparison
@@ -2990,13 +3042,28 @@ struct Odr_violation_compare
   bool
   operator()(const std::string& s1, const std::string& s2) const
   {
-    std::string::size_type pos1 = s1.rfind('/');
-    std::string::size_type pos2 = s2.rfind('/');
-    if (pos1 == std::string::npos
-       || pos2 == std::string::npos)
-      return s1 < s2;
-    return s1.compare(pos1, std::string::npos,
-                     s2, pos2, std::string::npos) < 0;
+    // Inputs should be of the form "dirname/filename:linenum" where
+    // "dirname/" is optional.  We want to compare just the filename.
+
+    // Find the last '/' and ':' in each string.
+    std::string::size_type s1begin = s1.rfind('/');
+    std::string::size_type s2begin = s2.rfind('/');
+    std::string::size_type s1end = s1.rfind(':');
+    std::string::size_type s2end = s2.rfind(':');
+    // If there was no '/' in a string, start at the beginning.
+    if (s1begin == std::string::npos)
+      s1begin = 0;
+    if (s2begin == std::string::npos)
+      s2begin = 0;
+    // If the ':' appeared in the directory name, compare to the end
+    // of the string.
+    if (s1end < s1begin)
+      s1end = s1.size();
+    if (s2end < s2begin)
+      s2end = s2.size();
+    // Compare takes lengths, not end indices.
+    return s1.compare(s1begin, s1end - s1begin,
+                     s2, s2begin, s2end - s2begin) < 0;
   }
 };
 
@@ -3012,8 +3079,11 @@ Symbol_table::detect_odr_violations(const Task* task,
        ++it)
     {
       const char* symbol_name = it->first;
-      // We use a sorted set so the output is deterministic.
-      std::set<std::string, Odr_violation_compare> line_nums;
+      // Maps from symbol location to a sample object file we found
+      // that location in.  We use a sorted map so the location order
+      // is deterministic, but we only store an arbitrary object file
+      // to avoid copying lots of names.
+      std::map<std::string, std::string, Odr_violation_compare> line_nums;
 
       for (Unordered_set<Symbol_location, Symbol_location_hash>::const_iterator
                locs = it->second.begin();
@@ -3032,7 +3102,11 @@ Symbol_table::detect_odr_violations(const Task* task,
           std::string lineno = Dwarf_line_info::one_addr2line(
               locs->object, locs->shndx, locs->offset, 16);
           if (!lineno.empty())
-            line_nums.insert(lineno);
+            {
+              std::string& sample_object = line_nums[lineno];
+              if (sample_object.empty())
+                sample_object = locs->object->name();
+            }
         }
 
       if (line_nums.size() > 1)
@@ -3040,10 +3114,12 @@ Symbol_table::detect_odr_violations(const Task* task,
           gold_warning(_("while linking %s: symbol '%s' defined in multiple "
                          "places (possible ODR violation):"),
                        output_file_name, demangle(symbol_name).c_str());
-          for (std::set<std::string>::const_iterator it2 = line_nums.begin();
-               it2 != line_nums.end();
-               ++it2)
-            fprintf(stderr, "  %s\n", it2->c_str());
+          for (std::map<std::string, std::string>::const_iterator it2 =
+                line_nums.begin();
+              it2 != line_nums.end();
+              ++it2)
+            fprintf(stderr, _("  %s from %s\n"),
+                    it2->first.c_str(), it2->second.c_str());
         }
     }
   // We only call one_addr2line() in this function, so we can clear its cache.
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