2008-06-12 David Edelsohn <edelsohn@gnu.org>
[deliverable/binutils-gdb.git] / gold / layout.cc
index e8582ca7a9ade548fb33a629feea072700eac94d..2c8c5241fb5eedba0c98860c3d49373d523e9eaa 100644 (file)
@@ -35,6 +35,7 @@
 
 #include "parameters.h"
 #include "options.h"
+#include "mapfile.h"
 #include "script.h"
 #include "script-sections.h"
 #include "output.h"
@@ -42,6 +43,7 @@
 #include "dynobj.h"
 #include "ehframe.h"
 #include "compressed_output.h"
+#include "reduced_debug_output.h"
 #include "reloc.h"
 #include "layout.h"
 
@@ -63,6 +65,13 @@ Layout_task_runner::run(Workqueue* workqueue, const Task* task)
 
   // Now we know the final size of the output file and we know where
   // each piece of information goes.
+
+  if (this->mapfile_ != NULL)
+    {
+      this->mapfile_->print_discarded_sections(this->input_objects_);
+      this->layout_->print_to_mapfile(this->mapfile_);
+    }
+
   Output_file* of = new Output_file(parameters->options().output_file_name());
   if (this->options_.oformat_enum() != General_options::OBJECT_FORMAT_ELF)
     of->set_is_temporary();
@@ -76,14 +85,36 @@ Layout_task_runner::run(Workqueue* workqueue, const Task* task)
 // Layout methods.
 
 Layout::Layout(const General_options& options, Script_options* script_options)
-  : options_(options), script_options_(script_options), namepool_(),
-    sympool_(), dynpool_(), signatures_(),
-    section_name_map_(), segment_list_(), section_list_(),
-    unattached_section_list_(), special_output_list_(),
-    section_headers_(NULL), tls_segment_(NULL), symtab_section_(NULL),
-    dynsym_section_(NULL), dynamic_section_(NULL), dynamic_data_(NULL),
-    eh_frame_section_(NULL), eh_frame_data_(NULL), eh_frame_hdr_section_(NULL),
-    build_id_note_(NULL), group_signatures_(), output_file_size_(-1),
+  : options_(options),
+    script_options_(script_options),
+    namepool_(),
+    sympool_(),
+    dynpool_(),
+    signatures_(),
+    section_name_map_(),
+    segment_list_(),
+    section_list_(),
+    unattached_section_list_(),
+    sections_are_attached_(false),
+    special_output_list_(),
+    section_headers_(NULL),
+    tls_segment_(NULL),
+    relro_segment_(NULL),
+    symtab_section_(NULL),
+    symtab_xindex_(NULL),
+    dynsym_section_(NULL),
+    dynsym_xindex_(NULL),
+    dynamic_section_(NULL),
+    dynamic_data_(NULL),
+    eh_frame_section_(NULL),
+    eh_frame_data_(NULL),
+    added_eh_frame_data_(false),
+    eh_frame_hdr_section_(NULL),
+    build_id_note_(NULL),
+    debug_abbrev_(NULL),
+    debug_info_(NULL),
+    group_signatures_(),
+    output_file_size_(-1),
     input_requires_executable_stack_(false),
     input_with_gnu_stack_note_(false),
     input_without_gnu_stack_note_(false),
@@ -132,6 +163,19 @@ static const char* gdb_sections[] =
   ".debug_str",
 };
 
+static const char* lines_only_debug_sections[] =
+{ ".debug_abbrev",
+  // ".debug_aranges",   // not used by gdb as of 6.7.1
+  // ".debug_frame",
+  ".debug_info",
+  ".debug_line",
+  // ".debug_loc",
+  // ".debug_macinfo",
+  // ".debug_pubnames",  // not used by gdb as of 6.7.1
+  // ".debug_ranges",
+  ".debug_str",
+};
+
 static inline bool
 is_gdb_debug_section(const char* str)
 {
@@ -142,6 +186,18 @@ is_gdb_debug_section(const char* str)
   return false;
 }
 
+static inline bool
+is_lines_only_debug_section(const char* str)
+{
+  // We can do this faster: binary search or a hashtable.  But why bother?
+  for (size_t i = 0;
+       i < sizeof(lines_only_debug_sections)/sizeof(*lines_only_debug_sections);
+       ++i)
+    if (strcmp(str, lines_only_debug_sections[i]) == 0)
+      return true;
+  return false;
+}
+
 // Whether to include this section in the link.
 
 template<int size, bool big_endian>
@@ -172,12 +228,16 @@ Layout::include_section(Sized_relobj<size, big_endian>*, const char* name,
     case elfcpp::SHT_PROGBITS:
       if (parameters->options().strip_debug()
          && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
+       {
+         if (is_debug_info_section(name))
+           return false;
+       }
+      if (parameters->options().strip_debug_non_line()
+         && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
        {
          // Debugging sections can only be recognized by name.
          if (is_prefix_of(".debug", name)
-             || is_prefix_of(".gnu.linkonce.wi.", name)
-             || is_prefix_of(".line", name)
-             || is_prefix_of(".stab", name))
+              && !is_lines_only_debug_section(name))
            return false;
        }
       if (parameters->options().strip_debug_gdb()
@@ -233,7 +293,15 @@ Output_section*
 Layout::get_output_section(const char* name, Stringpool::Key name_key,
                           elfcpp::Elf_Word type, elfcpp::Elf_Xword flags)
 {
-  const Key key(name_key, std::make_pair(type, flags));
+  elfcpp::Elf_Xword lookup_flags = flags;
+
+  // Ignoring SHF_WRITE and SHF_EXECINSTR here means that we combine
+  // read-write with read-only sections.  Some other ELF linkers do
+  // not do this.  FIXME: Perhaps there should be an option
+  // controlling this.
+  lookup_flags &= ~(elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR);
+
+  const Key key(name_key, std::make_pair(type, lookup_flags));
   const std::pair<Key, Output_section*> v(key, NULL);
   std::pair<Section_name_map::iterator, bool> ins(
     this->section_name_map_.insert(v));
@@ -267,11 +335,7 @@ Layout::get_output_section(const char* name, Stringpool::Key name_key,
               Section_name_map::iterator p =
                   this->section_name_map_.find(zero_key);
               if (p != this->section_name_map_.end())
-                {
-                  os = p->second;
-                  if ((flags & elfcpp::SHF_ALLOC) != 0)
-                    this->allocate_output_section(os, flags);
-                }
+               os = p->second;
             }
        }
 
@@ -284,17 +348,22 @@ Layout::get_output_section(const char* name, Stringpool::Key name_key,
 
 // Pick the output section to use for section NAME, in input file
 // RELOBJ, with type TYPE and flags FLAGS.  RELOBJ may be NULL for a
-// linker created section.  ADJUST_NAME is true if we should apply the
-// standard name mappings in Layout::output_section_name.  This will
-// return NULL if the input section should be discarded.
+// linker created section.  IS_INPUT_SECTION is true if we are
+// choosing an output section for an input section found in a input
+// file.  This will return NULL if the input section should be
+// discarded.
 
 Output_section*
 Layout::choose_output_section(const Relobj* relobj, const char* name,
                              elfcpp::Elf_Word type, elfcpp::Elf_Xword flags,
-                             bool adjust_name)
+                             bool is_input_section)
 {
-  // We should ignore some flags.  FIXME: This will need some
-  // adjustment for ld -r.
+  // We should not see any input sections after we have attached
+  // sections to segments.
+  gold_assert(!is_input_section || !this->sections_are_attached_);
+
+  // Some flags in the input section should not be automatically
+  // copied to the output section.
   flags &= ~ (elfcpp::SHF_INFO_LINK
              | elfcpp::SHF_LINK_ORDER
              | elfcpp::SHF_GROUP
@@ -323,17 +392,7 @@ Layout::choose_output_section(const Relobj* relobj, const char* name,
       if (output_section_slot != NULL)
        {
          if (*output_section_slot != NULL)
-            {
-              // If the output section was created unallocated, and we
-              // are now allocating it, then we need to clear the
-              // address set in the constructor and remove it from the
-              // unattached section list.
-              if (((*output_section_slot)->flags() & elfcpp::SHF_ALLOC) == 0
-                  && (flags & elfcpp::SHF_ALLOC) != 0)
-                this->allocate_output_section(*output_section_slot, flags);
-
-              return *output_section_slot;
-            }
+           return *output_section_slot;
 
          // We don't put sections found in the linker script into
          // SECTION_NAME_MAP_.  That keeps us from getting confused
@@ -355,7 +414,7 @@ Layout::choose_output_section(const Relobj* relobj, const char* name,
   // output section.
 
   size_t len = strlen(name);
-  if (adjust_name && !parameters->options().relocatable())
+  if (is_input_section && !parameters->options().relocatable())
     name = Layout::output_section_name(name, &len);
 
   Stringpool::Key name_key;
@@ -489,7 +548,8 @@ Layout::layout_group(Symbol_table* symtab,
                     const char* group_section_name,
                     const char* signature,
                     const elfcpp::Shdr<size, big_endian>& shdr,
-                    const elfcpp::Elf_Word* contents)
+                    elfcpp::Elf_Word flags,
+                    std::vector<unsigned int>* shndxes)
 {
   gold_assert(parameters->options().relocatable());
   gold_assert(shdr.get_sh_type() == elfcpp::SHT_GROUP);
@@ -517,7 +577,8 @@ Layout::layout_group(Symbol_table* symtab,
   section_size_type entry_count =
     convert_to_section_size_type(shdr.get_sh_size() / 4);
   Output_section_data* posd =
-    new Output_data_group<size, big_endian>(object, entry_count, contents);
+    new Output_data_group<size, big_endian>(object, entry_count, flags,
+                                           shndxes);
   os->add_output_section_data(posd);
 }
 
@@ -549,21 +610,10 @@ Layout::layout_eh_frame(Sized_relobj<size, big_endian>* object,
   if (os == NULL)
     return NULL;
 
-  // On some targets gcc assumes that a read-only .eh_frame section
-  // will be merged with a read-write .eh_frame section.
-  if ((shdr.get_sh_flags() & elfcpp::SHF_WRITE) != 0
-      && (os->flags() & elfcpp::SHF_WRITE) == 0)
-    {
-      elfcpp::Elf_Xword new_flags = os->flags() | elfcpp::SHF_WRITE;
-      this->write_enable_output_section(os, new_flags);
-      os->set_flags(new_flags);
-    }
-
   if (this->eh_frame_section_ == NULL)
     {
       this->eh_frame_section_ = os;
       this->eh_frame_data_ = new Eh_frame();
-      os->add_output_section_data(this->eh_frame_data_);
 
       if (this->options_.eh_frame_hdr())
        {
@@ -605,7 +655,21 @@ Layout::layout_eh_frame(Sized_relobj<size, big_endian>* object,
                                                      shndx,
                                                      reloc_shndx,
                                                      reloc_type))
-    *off = -1;
+    {
+      os->update_flags_for_input_section(shdr.get_sh_flags());
+
+      // We found a .eh_frame section we are going to optimize, so now
+      // we can add the set of optimized sections to the output
+      // section.  We need to postpone adding this until we've found a
+      // section we can optimize so that the .eh_frame section in
+      // crtbegin.o winds up at the start of the output section.
+      if (!this->added_eh_frame_data_)
+       {
+         os->add_output_section_data(this->eh_frame_data_);
+         this->added_eh_frame_data_ = true;
+       }
+      *off = -1;
+    }
   else
     {
       // We couldn't handle this .eh_frame section for some reason.
@@ -618,9 +682,10 @@ Layout::layout_eh_frame(Sized_relobj<size, big_endian>* object,
   return os;
 }
 
-// Add POSD to an output section using NAME, TYPE, and FLAGS.
+// Add POSD to an output section using NAME, TYPE, and FLAGS.  Return
+// the output section.
 
-void
+Output_section*
 Layout::add_output_section_data(const char* name, elfcpp::Elf_Word type,
                                elfcpp::Elf_Xword flags,
                                Output_section_data* posd)
@@ -629,6 +694,7 @@ Layout::add_output_section_data(const char* name, elfcpp::Elf_Word type,
                                                   false);
   if (os != NULL)
     os->add_output_section_data(posd);
+  return os;
 }
 
 // Map section flags to segment flags.
@@ -672,16 +738,30 @@ Layout::make_output_section(const char* name, elfcpp::Elf_Word type,
       && strcmp(this->options_.compress_debug_sections(), "none") != 0
       && is_compressible_debug_section(name))
     os = new Output_compressed_section(&this->options_, name, type, flags);
-  else
+
+  else if ((flags & elfcpp::SHF_ALLOC) == 0
+           && this->options_.strip_debug_non_line()
+           && strcmp(".debug_abbrev", name) == 0)
+    {
+      os = this->debug_abbrev_ = new Output_reduced_debug_abbrev_section(
+          name, type, flags);
+      if (this->debug_info_)
+        this->debug_info_->set_abbreviations(this->debug_abbrev_);
+    }
+  else if ((flags & elfcpp::SHF_ALLOC) == 0
+           && this->options_.strip_debug_non_line()
+           && strcmp(".debug_info", name) == 0)
+    {
+      os = this->debug_info_ = new Output_reduced_debug_info_section(
+          name, type, flags);
+      if (this->debug_abbrev_)
+        this->debug_info_->set_abbreviations(this->debug_abbrev_);
+    }
+ else
     os = new Output_section(name, type, flags);
 
   this->section_list_.push_back(os);
 
-  if ((flags & elfcpp::SHF_ALLOC) == 0)
-    this->unattached_section_list_.push_back(os);
-  else
-    this->attach_to_segment(os, flags);
-
   // The GNU linker by default sorts some sections by priority, so we
   // do the same.  We need to know that this might happen before we
   // attach any input sections.
@@ -692,14 +772,63 @@ Layout::make_output_section(const char* name, elfcpp::Elf_Word type,
          || strcmp(name, ".fini_array") == 0))
     os->set_may_sort_attached_input_sections();
 
+  // With -z relro, we have to recognize the special sections by name.
+  // There is no other way.
+  if (!this->script_options_->saw_sections_clause()
+      && parameters->options().relro()
+      && type == elfcpp::SHT_PROGBITS
+      && (flags & elfcpp::SHF_ALLOC) != 0
+      && (flags & elfcpp::SHF_WRITE) != 0)
+    {
+      if (strcmp(name, ".data.rel.ro") == 0)
+       os->set_is_relro();
+      else if (strcmp(name, ".data.rel.ro.local") == 0)
+       {
+         os->set_is_relro();
+         os->set_is_relro_local();
+       }
+    }
+
+  // If we have already attached the sections to segments, then we
+  // need to attach this one now.  This happens for sections created
+  // directly by the linker.
+  if (this->sections_are_attached_)
+    this->attach_section_to_segment(os);
+
   return os;
 }
 
+// Attach output sections to segments.  This is called after we have
+// seen all the input sections.
+
+void
+Layout::attach_sections_to_segments()
+{
+  for (Section_list::iterator p = this->section_list_.begin();
+       p != this->section_list_.end();
+       ++p)
+    this->attach_section_to_segment(*p);
+
+  this->sections_are_attached_ = true;
+}
+
+// Attach an output section to a segment.
+
+void
+Layout::attach_section_to_segment(Output_section* os)
+{
+  if ((os->flags() & elfcpp::SHF_ALLOC) == 0)
+    this->unattached_section_list_.push_back(os);
+  else
+    this->attach_allocated_section_to_segment(os);
+}
+
 // Attach an allocated output section to a segment.
 
 void
-Layout::attach_to_segment(Output_section* os, elfcpp::Elf_Xword flags)
+Layout::attach_allocated_section_to_segment(Output_section* os)
 {
+  elfcpp::Elf_Xword flags = os->flags();
   gold_assert((flags & elfcpp::SHF_ALLOC) != 0);
 
   if (parameters->options().relocatable())
@@ -785,6 +914,17 @@ Layout::attach_to_segment(Output_section* os, elfcpp::Elf_Xword flags)
                                                        seg_flags);
       this->tls_segment_->add_output_section(os, seg_flags);
     }
+
+  // If -z relro is in effect, and we see a relro section, we create a
+  // PT_GNU_RELRO segment.  There can only be one such segment.
+  if (os->is_relro() && parameters->options().relro())
+    {
+      gold_assert(seg_flags == (elfcpp::PF_R | elfcpp::PF_W));
+      if (this->relro_segment_ == NULL)
+       this->relro_segment_ = this->make_output_segment(elfcpp::PT_GNU_RELRO,
+                                                        seg_flags);
+      this->relro_segment_->add_output_section(os, seg_flags);
+    }
 }
 
 // Make an output section for a script.
@@ -799,58 +939,6 @@ Layout::make_output_section_for_script(const char* name)
   return os;
 }
 
-// We have to move an existing output section from the unallocated
-// list to the allocated list.
-
-void
-Layout::allocate_output_section(Output_section* os, elfcpp::Elf_Xword flags)
-{
-  os->reset_address_and_file_offset();
-
-  Section_list::iterator p = std::find(this->unattached_section_list_.begin(),
-                                       this->unattached_section_list_.end(),
-                                       os);
-  gold_assert(p != this->unattached_section_list_.end());
-  this->unattached_section_list_.erase(p);
-
-  this->attach_to_segment(os, flags);
-}
-
-// We have to move an existing output section from the read-only
-// segment to the writable segment.
-
-void
-Layout::write_enable_output_section(Output_section* os,
-                                    elfcpp::Elf_Xword flags)
-{
-  gold_assert((os->flags() & elfcpp::SHF_WRITE) == 0);
-  gold_assert(os->type() == elfcpp::SHT_PROGBITS);
-  gold_assert((flags & elfcpp::SHF_WRITE) != 0);
-  gold_assert((flags & elfcpp::SHF_ALLOC) != 0);
-
-  if (parameters->options().relocatable())
-    return;
-
-  if (this->script_options_->saw_sections_clause())
-    return;
-
-  Segment_list::iterator p;
-  for (p = this->segment_list_.begin();
-       p != this->segment_list_.end();
-       ++p)
-    {
-      if ((*p)->type() == elfcpp::PT_LOAD
-          && ((*p)->flags() & elfcpp::PF_W) == 0)
-        {
-          (*p)->remove_output_section(os);
-          break;
-        }
-    }
-  gold_assert(p != this->segment_list_.end());
-
-  this->attach_to_segment(os, flags);
-}
-
 // Return the number of segments we expect to see.
 
 size_t
@@ -907,6 +995,7 @@ Layout::create_initial_dynamic_sections(Symbol_table* symtab)
                                                       (elfcpp::SHF_ALLOC
                                                        | elfcpp::SHF_WRITE),
                                                       false);
+  this->dynamic_section_->set_is_relro();
 
   symtab->define_in_output_data("_DYNAMIC", NULL, this->dynamic_section_, 0, 0,
                                elfcpp::STT_OBJECT, elfcpp::STB_LOCAL,
@@ -1171,8 +1260,12 @@ Layout::finalize(const Input_objects* input_objects, Symbol_table* symtab,
   // sections.
   off = this->set_section_offsets(off, BEFORE_INPUT_SECTIONS_PASS);
 
+  // Set the section indexes of all unallocated sections seen so far,
+  // in case any of them are somehow referenced by a symbol.
+  shndx = this->set_section_indexes(shndx);
+
   // Create the symbol table sections.
-  this->create_symtab_sections(input_objects, symtab, &off);
+  this->create_symtab_sections(input_objects, symtab, shndx, &off);
   if (!parameters->doing_static_link())
     this->assign_local_dynsym_offsets(input_objects);
 
@@ -1187,11 +1280,12 @@ Layout::finalize(const Input_objects* input_objects, Symbol_table* symtab,
   // don't have to wait for the input sections.
   off = this->set_section_offsets(off, BEFORE_INPUT_SECTIONS_PASS);
 
-  // Now that all sections have been created, set the section indexes.
+  // Now that all sections have been created, set the section indexes
+  // for any sections which haven't been done yet.
   shndx = this->set_section_indexes(shndx);
 
   // Create the section table header.
-  this->create_shdrs(&off);
+  this->create_shdrs(shstrtab_section, &off);
 
   // If there are no sections which require postprocessing, we can
   // handle the section names now, and avoid a resize later.
@@ -1292,7 +1386,8 @@ Layout::create_note(const char* name, int note_type, size_t descsz,
                                                 elfcpp::SHT_NOTE,
                                                 flags);
   Output_section_data* posd = new Output_data_const_buffer(buffer, notehdrsz,
-                                                          size / 8);
+                                                          size / 8,
+                                                          "** note header");
   os->add_output_section_data(posd);
 
   *trailing_padding = aligned_descsz - descsz;
@@ -1320,7 +1415,7 @@ Layout::create_gold_note()
 
   if (trailing_padding > 0)
     {
-      posd = new Output_data_fixed_space(trailing_padding, 0);
+      posd = new Output_data_zero_fill(trailing_padding, 0);
       os->add_output_section_data(posd);
     }
 }
@@ -1457,7 +1552,7 @@ Layout::create_build_id()
 
       if (trailing_padding != 0)
        {
-         posd = new Output_data_fixed_space(trailing_padding, 0);
+         posd = new Output_data_zero_fill(trailing_padding, 0);
          os->add_output_section_data(posd);
        }
     }
@@ -1466,7 +1561,7 @@ Layout::create_build_id()
       // We need to compute a checksum after we have completed the
       // link.
       gold_assert(trailing_padding == 0);
-      this->build_id_note_ = new Output_data_fixed_space(descsz, 4);
+      this->build_id_note_ = new Output_data_zero_fill(descsz, 4);
       os->add_output_section_data(this->build_id_note_);
       os->set_after_input_sections();
     }
@@ -1509,12 +1604,25 @@ Layout::segment_precedes(const Output_segment* seg1,
   if (type2 == elfcpp::PT_LOAD && type1 != elfcpp::PT_LOAD)
     return false;
 
-  // We put the PT_TLS segment last, because that is where the dynamic
-  // linker expects to find it (this is just for efficiency; other
-  // positions would also work correctly).
-  if (type1 == elfcpp::PT_TLS && type2 != elfcpp::PT_TLS)
+  // We put the PT_TLS segment last except for the PT_GNU_RELRO
+  // segment, because that is where the dynamic linker expects to find
+  // it (this is just for efficiency; other positions would also work
+  // correctly).
+  if (type1 == elfcpp::PT_TLS
+      && type2 != elfcpp::PT_TLS
+      && type2 != elfcpp::PT_GNU_RELRO)
     return false;
-  if (type2 == elfcpp::PT_TLS && type1 != elfcpp::PT_TLS)
+  if (type2 == elfcpp::PT_TLS
+      && type1 != elfcpp::PT_TLS
+      && type1 != elfcpp::PT_GNU_RELRO)
+    return true;
+
+  // We put the PT_GNU_RELRO segment last, because that is where the
+  // dynamic linker expects to find it (as with PT_TLS, this is just
+  // for efficiency).
+  if (type1 == elfcpp::PT_GNU_RELRO && type2 != elfcpp::PT_GNU_RELRO)
+    return false;
+  if (type2 == elfcpp::PT_GNU_RELRO && type1 != elfcpp::PT_GNU_RELRO)
     return true;
 
   const elfcpp::Elf_Word flags1 = seg1->flags();
@@ -1838,18 +1946,15 @@ Layout::set_section_offsets(off_t off, Layout::Section_offset_pass pass)
 unsigned int
 Layout::set_section_indexes(unsigned int shndx)
 {
-  const bool output_is_object = parameters->options().relocatable();
   for (Section_list::iterator p = this->unattached_section_list_.begin();
        p != this->unattached_section_list_.end();
        ++p)
     {
-      // In a relocatable link, we already did group sections.
-      if (output_is_object
-         && (*p)->type() == elfcpp::SHT_GROUP)
-       continue;
-
-      (*p)->set_out_shndx(shndx);
-      ++shndx;
+      if (!(*p)->has_out_shndx())
+       {
+         (*p)->set_out_shndx(shndx);
+         ++shndx;
+       }
     }
   return shndx;
 }
@@ -1915,11 +2020,12 @@ Layout::count_local_symbols(const Task* task,
 
 // Create the symbol table sections.  Here we also set the final
 // values of the symbols.  At this point all the loadable sections are
-// fully laid out.
+// fully laid out.  SHNUM is the number of sections so far.
 
 void
 Layout::create_symtab_sections(const Input_objects* input_objects,
                               Symbol_table* symtab,
+                              unsigned int shnum,
                               off_t* poff)
 {
   int symsize;
@@ -2007,9 +2113,42 @@ Layout::create_symtab_sections(const Input_objects* input_objects,
       this->symtab_section_ = osymtab;
 
       Output_section_data* pos = new Output_data_fixed_space(off - startoff,
-                                                            align);
+                                                            align,
+                                                            "** symtab");
       osymtab->add_output_section_data(pos);
 
+      // We generate a .symtab_shndx section if we have more than
+      // SHN_LORESERVE sections.  Technically it is possible that we
+      // don't need one, because it is possible that there are no
+      // symbols in any of sections with indexes larger than
+      // SHN_LORESERVE.  That is probably unusual, though, and it is
+      // easier to always create one than to compute section indexes
+      // twice (once here, once when writing out the symbols).
+      if (shnum >= elfcpp::SHN_LORESERVE)
+       {
+         const char* symtab_xindex_name = this->namepool_.add(".symtab_shndx",
+                                                              false, NULL);
+         Output_section* osymtab_xindex =
+           this->make_output_section(symtab_xindex_name,
+                                     elfcpp::SHT_SYMTAB_SHNDX, 0);
+
+         size_t symcount = (off - startoff) / symsize;
+         this->symtab_xindex_ = new Output_symtab_xindex(symcount);
+
+         osymtab_xindex->add_output_section_data(this->symtab_xindex_);
+
+         osymtab_xindex->set_link_section(osymtab);
+         osymtab_xindex->set_addralign(4);
+         osymtab_xindex->set_entsize(4);
+
+         osymtab_xindex->set_after_input_sections();
+
+         // This tells the driver code to wait until the symbol table
+         // has written out before writing out the postprocessing
+         // sections, including the .symtab_shndx section.
+         this->any_postprocessing_sections_ = true;
+       }
+
       const char* strtab_name = this->namepool_.add(".strtab", false, NULL);
       Output_section* ostrtab = this->make_output_section(strtab_name,
                                                          elfcpp::SHT_STRTAB,
@@ -2057,14 +2196,15 @@ Layout::create_shstrtab()
 // offset.
 
 void
-Layout::create_shdrs(off_t* poff)
+Layout::create_shdrs(const Output_section* shstrtab_section, off_t* poff)
 {
   Output_section_headers* oshdrs;
   oshdrs = new Output_section_headers(this,
                                      &this->segment_list_,
                                      &this->section_list_,
                                      &this->unattached_section_list_,
-                                     &this->namepool_);
+                                     &this->namepool_,
+                                     shstrtab_section);
   off_t off = align_address(*poff, oshdrs->addralign());
   oshdrs->set_address_and_file_offset(0, off);
   off += oshdrs->data_size();
@@ -2072,6 +2212,19 @@ Layout::create_shdrs(off_t* poff)
   this->section_headers_ = oshdrs;
 }
 
+// Count the allocated sections.
+
+size_t
+Layout::allocated_output_section_count() const
+{
+  size_t section_count = 0;
+  for (Segment_list::const_iterator p = this->segment_list_.begin();
+       p != this->segment_list_.end();
+       ++p)
+    section_count += (*p)->output_section_count();
+  return section_count;
+}
+
 // Create the dynamic symbol table.
 
 void
@@ -2115,8 +2268,6 @@ Layout::create_dynamic_symtab(const Input_objects* input_objects,
   unsigned int local_symcount = index;
   *plocal_dynamic_count = local_symcount;
 
-  // FIXME: We have to tell set_dynsym_indexes whether the
-  // -E/--export-dynamic option was used.
   index = symtab->set_dynsym_indexes(index, pdynamic_symbols,
                                     &this->dynpool_, pversions);
 
@@ -2144,7 +2295,8 @@ Layout::create_dynamic_symtab(const Input_objects* input_objects,
                                                       false);
 
   Output_section_data* odata = new Output_data_fixed_space(index * symsize,
-                                                          align);
+                                                          align,
+                                                          "** dynsym");
   dynsym->add_output_section_data(odata);
 
   dynsym->set_info(local_symcount);
@@ -2157,6 +2309,37 @@ Layout::create_dynamic_symtab(const Input_objects* input_objects,
   odyn->add_section_address(elfcpp::DT_SYMTAB, dynsym);
   odyn->add_constant(elfcpp::DT_SYMENT, symsize);
 
+  // If there are more than SHN_LORESERVE allocated sections, we
+  // create a .dynsym_shndx section.  It is possible that we don't
+  // need one, because it is possible that there are no dynamic
+  // symbols in any of the sections with indexes larger than
+  // SHN_LORESERVE.  This is probably unusual, though, and at this
+  // time we don't know the actual section indexes so it is
+  // inconvenient to check.
+  if (this->allocated_output_section_count() >= elfcpp::SHN_LORESERVE)
+    {
+      Output_section* dynsym_xindex =
+       this->choose_output_section(NULL, ".dynsym_shndx",
+                                   elfcpp::SHT_SYMTAB_SHNDX,
+                                   elfcpp::SHF_ALLOC,
+                                   false);
+
+      this->dynsym_xindex_ = new Output_symtab_xindex(index);
+
+      dynsym_xindex->add_output_section_data(this->dynsym_xindex_);
+
+      dynsym_xindex->set_link_section(dynsym);
+      dynsym_xindex->set_addralign(4);
+      dynsym_xindex->set_entsize(4);
+
+      dynsym_xindex->set_after_input_sections();
+
+      // This tells the driver code to wait until the symbol table has
+      // written out before writing out the postprocessing sections,
+      // including the .dynsym_shndx section.
+      this->any_postprocessing_sections_ = true;
+    }
+
   // Create the dynamic string table section.
 
   Output_section* dynstr = this->choose_output_section(NULL, ".dynstr",
@@ -2192,7 +2375,8 @@ Layout::create_dynamic_symtab(const Input_objects* input_objects,
 
       Output_section_data* hashdata = new Output_data_const_buffer(phash,
                                                                   hashlen,
-                                                                  align);
+                                                                  align,
+                                                                  "** hash");
       hashsec->add_output_section_data(hashdata);
 
       hashsec->set_link_section(dynsym);
@@ -2216,7 +2400,8 @@ Layout::create_dynamic_symtab(const Input_objects* input_objects,
 
       Output_section_data* hashdata = new Output_data_const_buffer(phash,
                                                                   hashlen,
-                                                                  align);
+                                                                  align,
+                                                                  "** hash");
       hashsec->add_output_section_data(hashdata);
 
       hashsec->set_link_section(dynsym);
@@ -2318,7 +2503,8 @@ Layout::sized_create_version_sections(
                                                      dynamic_symbols,
                                                      &vbuf, &vsize);
 
-  Output_section_data* vdata = new Output_data_const_buffer(vbuf, vsize, 2);
+  Output_section_data* vdata = new Output_data_const_buffer(vbuf, vsize, 2,
+                                                           "** versions");
 
   vsec->add_output_section_data(vdata);
   vsec->set_entsize(2);
@@ -2341,9 +2527,8 @@ Layout::sized_create_version_sections(
       versions->def_section_contents<size, big_endian>(&this->dynpool_, &vdbuf,
                                                       &vdsize, &vdentries);
 
-      Output_section_data* vddata = new Output_data_const_buffer(vdbuf,
-                                                                vdsize,
-                                                                4);
+      Output_section_data* vddata =
+       new Output_data_const_buffer(vdbuf, vdsize, 4, "** version defs");
 
       vdsec->add_output_section_data(vddata);
       vdsec->set_link_section(dynstr);
@@ -2368,9 +2553,8 @@ Layout::sized_create_version_sections(
                                                        &vnbuf, &vnsize,
                                                        &vnentries);
 
-      Output_section_data* vndata = new Output_data_const_buffer(vnbuf,
-                                                                vnsize,
-                                                                4);
+      Output_section_data* vndata =
+       new Output_data_const_buffer(vnbuf, vnsize, 4, "** version refs");
 
       vnsec->add_output_section_data(vndata);
       vnsec->set_link_section(dynstr);
@@ -2407,7 +2591,7 @@ Layout::create_interp(const Target* target)
     {
       Output_segment* oseg = this->make_output_segment(elfcpp::PT_INTERP,
                                                       elfcpp::PF_R);
-      oseg->add_initial_output_section(osec, elfcpp::PF_R);
+      oseg->add_output_section(osec, elfcpp::PF_R);
     }
 }
 
@@ -2422,8 +2606,8 @@ Layout::finish_dynamic_section(const Input_objects* input_objects,
       Output_segment* oseg = this->make_output_segment(elfcpp::PT_DYNAMIC,
                                                       (elfcpp::PF_R
                                                        | elfcpp::PF_W));
-      oseg->add_initial_output_section(this->dynamic_section_,
-                                      elfcpp::PF_R | elfcpp::PF_W);
+      oseg->add_output_section(this->dynamic_section_,
+                              elfcpp::PF_R | elfcpp::PF_W);
     }
 
   Output_data_dynamic* const odyn = this->dynamic_data_;
@@ -2481,6 +2665,8 @@ Layout::finish_dynamic_section(const Input_objects* input_objects,
         }
 
       odyn->add_string(elfcpp::DT_RPATH, rpath_val);
+      if (parameters->options().enable_new_dtags())
+       odyn->add_string(elfcpp::DT_RUNPATH, rpath_val);
     }
 
   // Look for text segments that have dynamic relocations.
@@ -2531,6 +2717,28 @@ Layout::finish_dynamic_section(const Input_objects* input_objects,
   if (parameters->options().shared() && this->has_static_tls())
     flags |= elfcpp::DF_STATIC_TLS;
   odyn->add_constant(elfcpp::DT_FLAGS, flags);
+
+  flags = 0;
+  if (parameters->options().initfirst())
+    flags |= elfcpp::DF_1_INITFIRST;
+  if (parameters->options().interpose())
+    flags |= elfcpp::DF_1_INTERPOSE;
+  if (parameters->options().loadfltr())
+    flags |= elfcpp::DF_1_LOADFLTR;
+  if (parameters->options().nodefaultlib())
+    flags |= elfcpp::DF_1_NODEFLIB;
+  if (parameters->options().nodelete())
+    flags |= elfcpp::DF_1_NODELETE;
+  if (parameters->options().nodlopen())
+    flags |= elfcpp::DF_1_NOOPEN;
+  if (parameters->options().nodump())
+    flags |= elfcpp::DF_1_NODUMP;
+  if (!parameters->options().shared())
+    flags &= ~(elfcpp::DF_1_INITFIRST
+              | elfcpp::DF_1_NODELETE
+              | elfcpp::DF_1_NOOPEN);
+  if (flags)
+    odyn->add_constant(elfcpp::DT_FLAGS_1, flags);
 }
 
 // The mapping of .gnu.linkonce section names to real section names.
@@ -2538,7 +2746,8 @@ Layout::finish_dynamic_section(const Input_objects* input_objects,
 #define MAPPING_INIT(f, t) { f, sizeof(f) - 1, t, sizeof(t) - 1 }
 const Layout::Linkonce_mapping Layout::linkonce_mapping[] =
 {
-  MAPPING_INIT("d.rel.ro", ".data.rel.ro"),    // Must be before "d".
+  MAPPING_INIT("d.rel.ro.local", ".data.rel.ro.local"), // Before "d.rel.ro".
+  MAPPING_INIT("d.rel.ro", ".data.rel.ro"),            // Before "d".
   MAPPING_INIT("t", ".text"),
   MAPPING_INIT("r", ".rodata"),
   MAPPING_INIT("d", ".data"),
@@ -2640,6 +2849,9 @@ Layout::output_section_name(const char* name, size_t* plen)
   // initial '.', we use the name unchanged (i.e., "mysection" and
   // ".text" are unchanged).
 
+  // If the name starts with ".data.rel.ro.local" we use
+  // ".data.rel.ro.local".
+
   // If the name starts with ".data.rel.ro" we use ".data.rel.ro".
 
   // Otherwise, we drop the second '.' and everything that comes after
@@ -2653,6 +2865,13 @@ Layout::output_section_name(const char* name, size_t* plen)
   if (sdot == NULL)
     return name;
 
+  const char* const data_rel_ro_local = ".data.rel.ro.local";
+  if (strncmp(name, data_rel_ro_local, strlen(data_rel_ro_local)) == 0)
+    {
+      *plen = strlen(data_rel_ro_local);
+      return data_rel_ro_local;
+    }
+
   const char* const data_rel_ro = ".data.rel.ro";
   if (strncmp(name, data_rel_ro, strlen(data_rel_ro)) == 0)
     {
@@ -2672,11 +2891,12 @@ Layout::output_section_name(const char* name, size_t* plen)
 // want a linkonce signature to block another linkonce signature.
 
 bool
-Layout::add_comdat(const char* signature, bool group)
+Layout::add_comdat(Relobj* object, unsigned int shndx,
+                   const std::string& signature, bool group)
 {
-  std::string sig(signature);
+  Kept_section kept(object, shndx, group);
   std::pair<Signatures::iterator, bool> ins(
-    this->signatures_.insert(std::make_pair(sig, group)));
+    this->signatures_.insert(std::make_pair(signature, kept)));
 
   if (ins.second)
     {
@@ -2684,7 +2904,7 @@ Layout::add_comdat(const char* signature, bool group)
       return true;
     }
 
-  if (ins.first->second)
+  if (ins.first->second.group_)
     {
       // We've already seen a real section group with this signature.
       return false;
@@ -2694,7 +2914,7 @@ Layout::add_comdat(const char* signature, bool group)
       // This is a real section group, and we've already seen a
       // linkonce section with this signature.  Record that we've seen
       // a section group, and don't include this section group.
-      ins.first->second = true;
+      ins.first->second.group_ = true;
       return false;
     }
   else
@@ -2706,6 +2926,20 @@ Layout::add_comdat(const char* signature, bool group)
     }
 }
 
+// Find the given comdat signature, and return the object and section
+// index of the kept group.
+Relobj*
+Layout::find_kept_object(const std::string& signature,
+                         unsigned int* pshndx) const
+{
+  Signatures::const_iterator p = this->signatures_.find(signature);
+  if (p == this->signatures_.end())
+    return NULL;
+  if (pshndx != NULL)
+    *pshndx = p->second.shndx_;
+  return p->second.object_;
+}
+
 // Store the allocated sections into the section list.
 
 void
@@ -2764,7 +2998,7 @@ Layout::write_data(const Symbol_table* symtab, Output_file* of) const
              gold_assert(index > 0 && index != -1U);
              off_t off = (symtab_section->offset()
                           + index * symtab_section->entsize());
-             symtab->write_section_symbol(*p, of, off);
+             symtab->write_section_symbol(*p, this->symtab_xindex_, of, off);
            }
        }
     }
@@ -2781,7 +3015,7 @@ Layout::write_data(const Symbol_table* symtab, Output_file* of) const
          gold_assert(index > 0 && index != -1U);
          off_t off = (dynsym_section->offset()
                       + index * dynsym_section->entsize());
-         symtab->write_section_symbol(*p, of, off);
+         symtab->write_section_symbol(*p, this->dynsym_xindex_, of, off);
        }
     }
 
@@ -2919,6 +3153,17 @@ Layout::write_binary(Output_file* in) const
   out.close();
 }
 
+// Print the output sections to the map file.
+
+void
+Layout::print_to_mapfile(Mapfile* mapfile) const
+{
+  for (Segment_list::const_iterator p = this->segment_list_.begin();
+       p != this->segment_list_.end();
+       ++p)
+    (*p)->print_sections_to_mapfile(mapfile);
+}
+
 // Print statistical information to stderr.  This is used for --stats.
 
 void
@@ -3012,7 +3257,8 @@ void
 Write_symbols_task::run(Workqueue*)
 {
   this->symtab_->write_globals(this->input_objects_, this->sympool_,
-                              this->dynpool_, this->of_);
+                              this->dynpool_, this->layout_->symtab_xindex(),
+                              this->layout_->dynsym_xindex(), this->of_);
 }
 
 // Write_after_input_sections_task methods.
@@ -3148,7 +3394,8 @@ Layout::layout_group<32, false>(Symbol_table* symtab,
                                const char* group_section_name,
                                const char* signature,
                                const elfcpp::Shdr<32, false>& shdr,
-                               const elfcpp::Elf_Word* contents);
+                               elfcpp::Elf_Word flags,
+                               std::vector<unsigned int>* shndxes);
 #endif
 
 #ifdef HAVE_TARGET_32_BIG
@@ -3160,7 +3407,8 @@ Layout::layout_group<32, true>(Symbol_table* symtab,
                               const char* group_section_name,
                               const char* signature,
                               const elfcpp::Shdr<32, true>& shdr,
-                              const elfcpp::Elf_Word* contents);
+                              elfcpp::Elf_Word flags,
+                              std::vector<unsigned int>* shndxes);
 #endif
 
 #ifdef HAVE_TARGET_64_LITTLE
@@ -3172,7 +3420,8 @@ Layout::layout_group<64, false>(Symbol_table* symtab,
                                const char* group_section_name,
                                const char* signature,
                                const elfcpp::Shdr<64, false>& shdr,
-                               const elfcpp::Elf_Word* contents);
+                               elfcpp::Elf_Word flags,
+                               std::vector<unsigned int>* shndxes);
 #endif
 
 #ifdef HAVE_TARGET_64_BIG
@@ -3184,7 +3433,8 @@ Layout::layout_group<64, true>(Symbol_table* symtab,
                               const char* group_section_name,
                               const char* signature,
                               const elfcpp::Shdr<64, true>& shdr,
-                              const elfcpp::Elf_Word* contents);
+                              elfcpp::Elf_Word flags,
+                              std::vector<unsigned int>* shndxes);
 #endif
 
 #ifdef HAVE_TARGET_32_LITTLE
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