]> git.ipfire.org Git - thirdparty/binutils-gdb.git/blobdiff - gold/layout.cc
Update year range in copyright notice of binutils files
[thirdparty/binutils-gdb.git] / gold / layout.cc
index c12037671fdfa9abfeff89607b8a0158f65e144a..a27cb071c75d8537800b096287d23eda6cd8a2e0 100644 (file)
@@ -1,6 +1,6 @@
 // layout.cc -- lay out output file sections for gold
 
-// Copyright 2006, 2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
+// Copyright (C) 2006-2021 Free Software Foundation, Inc.
 // Written by Ian Lance Taylor <iant@google.com>.
 
 // This file is part of gold.
 #include "libiberty.h"
 #include "md5.h"
 #include "sha1.h"
+#ifdef __MINGW32__
+#include <windows.h>
+#include <rpcdce.h>
+#endif
 
 #include "parameters.h"
 #include "options.h"
@@ -44,6 +48,7 @@
 #include "symtab.h"
 #include "dynobj.h"
 #include "ehframe.h"
+#include "gdb-index.h"
 #include "compressed_output.h"
 #include "reduced_debug_output.h"
 #include "object.h"
@@ -154,9 +159,9 @@ off_t
 Free_list::allocate(off_t len, uint64_t align, off_t minoff)
 {
   gold_debug(DEBUG_INCREMENTAL,
-            "Free_list::allocate(%08lx, %d, %08lx)",
-            static_cast<long>(len), static_cast<int>(align),
-            static_cast<long>(minoff));
+            "Free_list::allocate(%08lx, %d, %08lx)",
+            static_cast<long>(len), static_cast<int>(align),
+            static_cast<long>(minoff));
   if (len == 0)
     return align_address(minoff, align);
 
@@ -221,19 +226,63 @@ void
 Free_list::print_stats()
 {
   fprintf(stderr, _("%s: total free lists: %u\n"),
-          program_name, Free_list::num_lists);
+         program_name, Free_list::num_lists);
   fprintf(stderr, _("%s: total free list nodes: %u\n"),
-          program_name, Free_list::num_nodes);
+         program_name, Free_list::num_nodes);
   fprintf(stderr, _("%s: calls to Free_list::remove: %u\n"),
-          program_name, Free_list::num_removes);
+         program_name, Free_list::num_removes);
   fprintf(stderr, _("%s: nodes visited: %u\n"),
-          program_name, Free_list::num_remove_visits);
+         program_name, Free_list::num_remove_visits);
   fprintf(stderr, _("%s: calls to Free_list::allocate: %u\n"),
-          program_name, Free_list::num_allocates);
+         program_name, Free_list::num_allocates);
   fprintf(stderr, _("%s: nodes visited: %u\n"),
-          program_name, Free_list::num_allocate_visits);
+         program_name, Free_list::num_allocate_visits);
 }
 
+// A Hash_task computes the MD5 checksum of an array of char.
+
+class Hash_task : public Task
+{
+ public:
+  Hash_task(Output_file* of,
+           size_t offset,
+           size_t size,
+           unsigned char* dst,
+           Task_token* final_blocker)
+    : of_(of), offset_(offset), size_(size), dst_(dst),
+      final_blocker_(final_blocker)
+  { }
+
+  void
+  run(Workqueue*)
+  {
+    const unsigned char* iv =
+       this->of_->get_input_view(this->offset_, this->size_);
+    md5_buffer(reinterpret_cast<const char*>(iv), this->size_, this->dst_);
+    this->of_->free_input_view(this->offset_, this->size_, iv);
+  }
+
+  Task_token*
+  is_runnable()
+  { return NULL; }
+
+  // Unblock FINAL_BLOCKER_ when done.
+  void
+  locks(Task_locker* tl)
+  { tl->add(this, this->final_blocker_); }
+
+  std::string
+  get_name() const
+  { return "Hash_task"; }
+
+ private:
+  Output_file* of_;
+  const size_t offset_;
+  const size_t size_;
+  unsigned char* const dst_;
+  Task_token* const final_blocker_;
+};
+
 // Layout::Relaxation_debug_check methods.
 
 // Check that sections and special data are in reset states.
@@ -243,7 +292,8 @@ Free_list::print_stats()
 void
 Layout::Relaxation_debug_check::check_output_data_for_reset_values(
     const Layout::Section_list& sections,
-    const Layout::Data_list& special_outputs)
+    const Layout::Data_list& special_outputs,
+    const Layout::Data_list& relax_outputs)
 {
   for(Layout::Section_list::const_iterator p = sections.begin();
       p != sections.end();
@@ -254,8 +304,10 @@ Layout::Relaxation_debug_check::check_output_data_for_reset_values(
       p != special_outputs.end();
       ++p)
     gold_assert((*p)->address_and_file_offset_have_reset_values());
+
+  gold_assert(relax_outputs.empty());
 }
-  
+
 // Save information of SECTIONS for checking later.
 
 void
@@ -315,10 +367,14 @@ Layout::Relaxation_debug_check::verify_sections(
 void
 Layout_task_runner::run(Workqueue* workqueue, const Task* task)
 {
+  // See if any of the input definitions violate the One Definition Rule.
+  // TODO: if this is too slow, do this as a task, rather than inline.
+  this->symtab_->detect_odr_violations(task, this->options_.output_file_name());
+
   Layout* layout = this->layout_;
   off_t file_size = layout->finalize(this->input_objects_,
                                     this->symtab_,
-                                     this->target_,
+                                    this->target_,
                                     task);
 
   // Now we know the final size of the output file and we know where
@@ -348,8 +404,8 @@ Layout_task_runner::run(Workqueue* workqueue, const Task* task)
       // incremental information from the file before (possibly)
       // overwriting it.
       if (parameters->incremental_update())
-        layout->incremental_base()->apply_incremental_relocs(this->symtab_,
-                                                            this->layout_,
+       layout->incremental_base()->apply_incremental_relocs(this->symtab_,
+                                                            this->layout_,
                                                             of);
 
       of->resize(file_size);
@@ -374,6 +430,7 @@ Layout::Layout(int number_of_input_files, Script_options* script_options)
     section_list_(),
     unattached_section_list_(),
     special_output_list_(),
+    relax_output_list_(),
     section_headers_(NULL),
     tls_segment_(NULL),
     relro_segment_(NULL),
@@ -390,6 +447,7 @@ Layout::Layout(int number_of_input_files, Script_options* script_options)
     eh_frame_data_(NULL),
     added_eh_frame_data_(false),
     eh_frame_hdr_section_(NULL),
+    gdb_index_data_(NULL),
     build_id_note_(NULL),
     debug_abbrev_(NULL),
     debug_info_(NULL),
@@ -405,16 +463,20 @@ Layout::Layout(int number_of_input_files, Script_options* script_options)
     resized_signatures_(false),
     have_stabstr_section_(false),
     section_ordering_specified_(false),
+    unique_segment_for_sections_specified_(false),
     incremental_inputs_(NULL),
     record_output_section_data_from_script_(false),
+    lto_slim_object_(false),
     script_output_section_data_list_(),
     segment_states_(NULL),
     relaxation_debug_check_(NULL),
     section_order_map_(),
+    section_segment_map_(),
     input_section_position_(),
     input_section_glob_(),
     incremental_base_(NULL),
-    free_list_()
+    free_list_(),
+    gnu_properties_()
 {
   // Make space for more than enough segments for a typical file.
   // This is just for efficiency--it's OK if we wind up needing more.
@@ -450,56 +512,108 @@ Layout::Hash_key::operator()(const Layout::Key& k) const
  return k.first + k.second.first + k.second.second;
 }
 
-// Returns whether the given section is in the list of
-// debug-sections-used-by-some-version-of-gdb.  Currently,
-// we've checked versions of gdb up to and including 6.7.1.
+// These are the debug sections that are actually used by gdb.
+// Currently, we've checked versions of gdb up to and including 7.4.
+// We only check the part of the name that follows ".debug_" or
+// ".zdebug_".
 
 static const char* gdb_sections[] =
-{ ".debug_abbrev",
-  // ".debug_aranges",   // not used by gdb as of 6.7.1
-  ".debug_frame",
-  ".debug_info",
-  ".debug_types",
-  ".debug_line",
-  ".debug_loc",
-  ".debug_macinfo",
-  // ".debug_pubnames",  // not used by gdb as of 6.7.1
-  ".debug_ranges",
-  ".debug_str",
+{
+  "abbrev",
+  "addr",         // Fission extension
+  // "aranges",   // not used by gdb as of 7.4
+  "frame",
+  "gdb_scripts",
+  "info",
+  "types",
+  "line",
+  "loc",
+  "macinfo",
+  "macro",
+  // "pubnames",  // not used by gdb as of 7.4
+  // "pubtypes",  // not used by gdb as of 7.4
+  // "gnu_pubnames",  // Fission extension
+  // "gnu_pubtypes",  // Fission extension
+  "ranges",
+  "str",
+  "str_offsets",
 };
 
+// This is the minimum set of sections needed for line numbers.
+
 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_types",
-  ".debug_line",
-  // ".debug_loc",
-  // ".debug_macinfo",
-  // ".debug_pubnames",  // not used by gdb as of 6.7.1
-  // ".debug_ranges",
-  ".debug_str",
+{
+  "abbrev",
+  // "addr",      // Fission extension
+  // "aranges",   // not used by gdb as of 7.4
+  // "frame",
+  // "gdb_scripts",
+  "info",
+  // "types",
+  "line",
+  // "loc",
+  // "macinfo",
+  // "macro",
+  // "pubnames",  // not used by gdb as of 7.4
+  // "pubtypes",  // not used by gdb as of 7.4
+  // "gnu_pubnames",  // Fission extension
+  // "gnu_pubtypes",  // Fission extension
+  // "ranges",
+  "str",
+  "str_offsets",  // Fission extension
 };
 
+// These sections are the DWARF fast-lookup tables, and are not needed
+// when building a .gdb_index section.
+
+static const char* gdb_fast_lookup_sections[] =
+{
+  "aranges",
+  "pubnames",
+  "gnu_pubnames",
+  "pubtypes",
+  "gnu_pubtypes",
+};
+
+// Returns whether the given debug section is in the list of
+// debug-sections-used-by-some-version-of-gdb.  SUFFIX is the
+// portion of the name following ".debug_" or ".zdebug_".
+
 static inline bool
-is_gdb_debug_section(const char* str)
+is_gdb_debug_section(const char* suffix)
 {
   // We can do this faster: binary search or a hashtable.  But why bother?
   for (size_t i = 0; i < sizeof(gdb_sections)/sizeof(*gdb_sections); ++i)
-    if (strcmp(str, gdb_sections[i]) == 0)
+    if (strcmp(suffix, gdb_sections[i]) == 0)
       return true;
   return false;
 }
 
+// Returns whether the given section is needed for lines-only debugging.
+
 static inline bool
-is_lines_only_debug_section(const char* str)
+is_lines_only_debug_section(const char* suffix)
 {
   // 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)
+    if (strcmp(suffix, lines_only_debug_sections[i]) == 0)
+      return true;
+  return false;
+}
+
+// Returns whether the given section is a fast-lookup section that
+// will not be needed when building a .gdb_index section.
+
+static inline bool
+is_gdb_fast_lookup_section(const char* suffix)
+{
+  // We can do this faster: binary search or a hashtable.  But why bother?
+  for (size_t i = 0;
+       i < sizeof(gdb_fast_lookup_sections)/sizeof(*gdb_fast_lookup_sections);
+       ++i)
+    if (strcmp(suffix, gdb_fast_lookup_sections[i]) == 0)
       return true;
   return false;
 }
@@ -528,6 +642,15 @@ is_compressed_debug_section(const char* secname)
   return (is_prefix_of(".zdebug", secname));
 }
 
+std::string
+corresponding_uncompressed_section_name(std::string secname)
+{
+  gold_assert(secname[0] == '.' && secname[1] == 'z');
+  std::string ret(".");
+  ret.append(secname, 2, std::string::npos);
+  return ret;
+}
+
 // Whether to include this section in the link.
 
 template<int size, bool big_endian>
@@ -535,10 +658,17 @@ bool
 Layout::include_section(Sized_relobj_file<size, big_endian>*, const char* name,
                        const elfcpp::Shdr<size, big_endian>& shdr)
 {
-  if (shdr.get_sh_flags() & elfcpp::SHF_EXCLUDE)
+  if (!parameters->options().relocatable()
+      && (shdr.get_sh_flags() & elfcpp::SHF_EXCLUDE))
     return false;
 
-  switch (shdr.get_sh_type())
+  elfcpp::Elf_Word sh_type = shdr.get_sh_type();
+
+  if ((sh_type >= elfcpp::SHT_LOOS && sh_type <= elfcpp::SHT_HIOS)
+      || (sh_type >= elfcpp::SHT_LOPROC && sh_type <= elfcpp::SHT_HIPROC))
+    return parameters->target().should_include_section(sh_type);
+
+  switch (sh_type)
     {
     case elfcpp::SHT_NULL:
     case elfcpp::SHT_SYMTAB:
@@ -561,8 +691,7 @@ Layout::include_section(Sized_relobj_file<size, big_endian>*, const char* name,
     case elfcpp::SHT_GROUP:
       // If we are emitting relocations these should be handled
       // elsewhere.
-      gold_assert(!parameters->options().relocatable()
-                 && !parameters->options().emit_relocs());
+      gold_assert(!parameters->options().relocatable());
       return false;
 
     case elfcpp::SHT_PROGBITS:
@@ -576,26 +705,44 @@ Layout::include_section(Sized_relobj_file<size, big_endian>*, const char* name,
          && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
        {
          // Debugging sections can only be recognized by name.
-         if (is_prefix_of(".debug", name)
-              && !is_lines_only_debug_section(name))
+         if (is_prefix_of(".debug_", name)
+             && !is_lines_only_debug_section(name + 7))
+           return false;
+         if (is_prefix_of(".zdebug_", name)
+             && !is_lines_only_debug_section(name + 8))
            return false;
        }
       if (parameters->options().strip_debug_gdb()
          && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
        {
          // Debugging sections can only be recognized by name.
-         if (is_prefix_of(".debug", name)
-              && !is_gdb_debug_section(name))
+         if (is_prefix_of(".debug_", name)
+             && !is_gdb_debug_section(name + 7))
+           return false;
+         if (is_prefix_of(".zdebug_", name)
+             && !is_gdb_debug_section(name + 8))
+           return false;
+       }
+      if (parameters->options().gdb_index()
+         && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
+       {
+         // When building .gdb_index, we can strip .debug_pubnames,
+         // .debug_pubtypes, and .debug_aranges sections.
+         if (is_prefix_of(".debug_", name)
+             && is_gdb_fast_lookup_section(name + 7))
+           return false;
+         if (is_prefix_of(".zdebug_", name)
+             && is_gdb_fast_lookup_section(name + 8))
            return false;
        }
       if (parameters->options().strip_lto_sections()
-          && !parameters->options().relocatable()
-          && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
-        {
-          // Ignore LTO sections containing intermediate code.
-          if (is_prefix_of(".gnu.lto_", name))
-            return false;
-        }
+         && !parameters->options().relocatable()
+         && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
+       {
+         // Ignore LTO sections containing intermediate code.
+         if (is_prefix_of(".gnu.lto_", name))
+           return false;
+       }
       // The GNU linker strips .gnu_debuglink sections, so we do too.
       // This is a feature used to keep debugging information in
       // separate files.
@@ -711,27 +858,27 @@ Layout::get_output_section(const char* name, Stringpool::Key name_key,
 
       if (lookup_type == elfcpp::SHT_PROGBITS)
        {
-          if (flags == 0)
-            {
-              Output_section* same_name = this->find_output_section(name);
-              if (same_name != NULL
-                  && (same_name->type() == elfcpp::SHT_PROGBITS
+         if (flags == 0)
+           {
+             Output_section* same_name = this->find_output_section(name);
+             if (same_name != NULL
+                 && (same_name->type() == elfcpp::SHT_PROGBITS
                      || same_name->type() == elfcpp::SHT_INIT_ARRAY
                      || same_name->type() == elfcpp::SHT_FINI_ARRAY
                      || same_name->type() == elfcpp::SHT_PREINIT_ARRAY)
-                  && (same_name->flags() & elfcpp::SHF_TLS) == 0)
-                os = same_name;
-            }
-          else if ((flags & elfcpp::SHF_TLS) == 0)
-            {
-              elfcpp::Elf_Xword zero_flags = 0;
-              const Key zero_key(name_key, std::make_pair(lookup_type,
+                 && (same_name->flags() & elfcpp::SHF_TLS) == 0)
+               os = same_name;
+           }
+         else if ((flags & elfcpp::SHF_TLS) == 0)
+           {
+             elfcpp::Elf_Xword zero_flags = 0;
+             const Key zero_key(name_key, std::make_pair(lookup_type,
                                                          zero_flags));
-              Section_name_map::iterator p =
-                  this->section_name_map_.find(zero_key);
-              if (p != this->section_name_map_.end())
+             Section_name_map::iterator p =
+                 this->section_name_map_.find(zero_key);
+             if (p != this->section_name_map_.end())
                os = p->second;
-            }
+           }
        }
 
       if (os == NULL)
@@ -742,37 +889,72 @@ Layout::get_output_section(const char* name, Stringpool::Key name_key,
     }
 }
 
+// Returns TRUE iff NAME (an input section from RELOBJ) will
+// be mapped to an output section that should be KEPT.
+
+bool
+Layout::keep_input_section(const Relobj* relobj, const char* name)
+{
+  if (! this->script_options_->saw_sections_clause())
+    return false;
+
+  Script_sections* ss = this->script_options_->script_sections();
+  const char* file_name = relobj == NULL ? NULL : relobj->name().c_str();
+  Output_section** output_section_slot;
+  Script_sections::Section_type script_section_type;
+  bool keep;
+
+  name = ss->output_section_name(file_name, name, &output_section_slot,
+                                &script_section_type, &keep, true);
+  return name != NULL && keep;
+}
+
+// Clear the input section flags that should not be copied to the
+// output section.
+
+elfcpp::Elf_Xword
+Layout::get_output_section_flags(elfcpp::Elf_Xword input_section_flags)
+{
+  // Some flags in the input section should not be automatically
+  // copied to the output section.
+  input_section_flags &= ~ (elfcpp::SHF_INFO_LINK
+                           | elfcpp::SHF_GROUP
+                           | elfcpp::SHF_COMPRESSED
+                           | elfcpp::SHF_MERGE
+                           | elfcpp::SHF_STRINGS);
+
+  // We only clear the SHF_LINK_ORDER flag in for
+  // a non-relocatable link.
+  if (!parameters->options().relocatable())
+    input_section_flags &= ~elfcpp::SHF_LINK_ORDER;
+
+  return input_section_flags;
+}
+
 // 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.  IS_INPUT_SECTION is true if we are
 // choosing an output section for an input section found in a input
 // file.  ORDER is where this section should appear in the output
 // sections.  IS_RELRO is true for a relro section.  This will return
-// NULL if the input section should be discarded.
+// NULL if the input section should be discarded.  MATCH_INPUT_SPEC
+// is true if the section name should be matched against input specs
+// in a linker script.
 
 Output_section*
 Layout::choose_output_section(const Relobj* relobj, const char* name,
                              elfcpp::Elf_Word type, elfcpp::Elf_Xword flags,
                              bool is_input_section, Output_section_order order,
-                             bool is_relro)
+                             bool is_relro, bool is_reloc,
+                             bool match_input_spec)
 {
   // 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_GROUP
-             | elfcpp::SHF_MERGE
-             | elfcpp::SHF_STRINGS);
-
-  // We only clear the SHF_LINK_ORDER flag in for
-  // a non-relocatable link.
-  if (!parameters->options().relocatable())
-    flags &= ~elfcpp::SHF_LINK_ORDER;
+  flags = this->get_output_section_flags(flags);
 
-  if (this->script_options_->saw_sections_clause())
+  if (this->script_options_->saw_sections_clause() && !is_reloc)
     {
       // We are using a SECTIONS clause, so the output section is
       // chosen based only on the name.
@@ -782,8 +964,11 @@ Layout::choose_output_section(const Relobj* relobj, const char* name,
       Output_section** output_section_slot;
       Script_sections::Section_type script_section_type;
       const char* orig_name = name;
+      bool keep;
       name = ss->output_section_name(file_name, name, &output_section_slot,
-                                    &script_section_type);
+                                    &script_section_type, &keep,
+                                    match_input_spec);
+
       if (name == NULL)
        {
          gold_debug(DEBUG_SCRIPT, _("Unable to create output section '%s' "
@@ -856,19 +1041,16 @@ Layout::choose_output_section(const Relobj* relobj, const char* name,
   // FIXME: Handle SHF_OS_NONCONFORMING somewhere.
 
   size_t len = strlen(name);
-  char* uncompressed_name = NULL;
+  std::string uncompressed_name;
 
   // Compressed debug sections should be mapped to the corresponding
   // uncompressed section.
   if (is_compressed_debug_section(name))
     {
-      uncompressed_name = new char[len];
-      uncompressed_name[0] = '.';
-      gold_assert(name[0] == '.' && name[1] == 'z');
-      strncpy(&uncompressed_name[1], &name[2], len - 2);
-      uncompressed_name[len - 1] = '\0';
-      len -= 1;
-      name = uncompressed_name;
+      uncompressed_name =
+         corresponding_uncompressed_section_name(std::string(name, len));
+      name = uncompressed_name.c_str();
+      len = uncompressed_name.length();
     }
 
   // Turn NAME from the name of the input section into the name of the
@@ -876,14 +1058,16 @@ Layout::choose_output_section(const Relobj* relobj, const char* name,
   if (is_input_section
       && !this->script_options_->saw_sections_clause()
       && !parameters->options().relocatable())
-    name = Layout::output_section_name(relobj, name, &len);
+    {
+      const char *orig_name = name;
+      name = parameters->target().output_section_name(relobj, name, &len);
+      if (name == NULL)
+       name = Layout::output_section_name(relobj, orig_name, &len);
+    }
 
   Stringpool::Key name_key;
   name = this->namepool_.add_with_length(name, len, true, &name_key);
 
-  if (uncompressed_name != NULL)
-    delete[] uncompressed_name;
-
   // Find or make the output section.  The output section is selected
   // based on the section name, type, and flags.
   return this->get_output_section(name, name_key, type, flags, order, is_relro);
@@ -905,10 +1089,18 @@ Layout::init_fixed_output_section(const char* name,
   if (!can_incremental_update(sh_type))
     return NULL;
 
+  // If we're generating a .gdb_index section, we need to regenerate
+  // it from scratch.
+  if (parameters->options().gdb_index()
+      && sh_type == elfcpp::SHT_PROGBITS
+      && strcmp(name, ".gdb_index") == 0)
+    return NULL;
+
   typename elfcpp::Elf_types<size>::Elf_Addr sh_addr = shdr.get_sh_addr();
   typename elfcpp::Elf_types<size>::Elf_Off sh_offset = shdr.get_sh_offset();
   typename elfcpp::Elf_types<size>::Elf_WXword sh_size = shdr.get_sh_size();
-  typename elfcpp::Elf_types<size>::Elf_WXword sh_flags = shdr.get_sh_flags();
+  typename elfcpp::Elf_types<size>::Elf_WXword sh_flags =
+      this->get_output_section_flags(shdr.get_sh_flags());
   typename elfcpp::Elf_types<size>::Elf_WXword sh_addralign =
       shdr.get_sh_addralign();
 
@@ -916,13 +1108,41 @@ Layout::init_fixed_output_section(const char* name,
   Stringpool::Key name_key;
   name = this->namepool_.add(name, true, &name_key);
   Output_section* os = this->get_output_section(name, name_key, sh_type,
-                                               sh_flags, ORDER_INVALID, false);
+                                               sh_flags, ORDER_INVALID, false);
   os->set_fixed_layout(sh_addr, sh_offset, sh_size, sh_addralign);
   if (sh_type != elfcpp::SHT_NOBITS)
     this->free_list_.remove(sh_offset, sh_offset + sh_size);
   return os;
 }
 
+// Return the index by which an input section should be ordered.  This
+// is used to sort some .text sections, for compatibility with GNU ld.
+
+int
+Layout::special_ordering_of_input_section(const char* name)
+{
+  // The GNU linker has some special handling for some sections that
+  // wind up in the .text section.  Sections that start with these
+  // prefixes must appear first, and must appear in the order listed
+  // here.
+  static const char* const text_section_sort[] =
+  {
+    ".text.unlikely",
+    ".text.exit",
+    ".text.startup",
+    ".text.hot",
+    ".text.sorted"
+  };
+
+  for (size_t i = 0;
+       i < sizeof(text_section_sort) / sizeof(text_section_sort[0]);
+       i++)
+    if (is_prefix_of(text_section_sort[i], name))
+      return i;
+
+  return -1;
+}
+
 // Return the output section to use for input section SHNDX, with name
 // NAME, with header HEADER, from object OBJECT.  RELOC_SHNDX is the
 // index of a relocation section which applies to this section, or 0
@@ -937,30 +1157,85 @@ template<int size, bool big_endian>
 Output_section*
 Layout::layout(Sized_relobj_file<size, big_endian>* object, unsigned int shndx,
               const char* name, const elfcpp::Shdr<size, big_endian>& shdr,
-              unsigned int reloc_shndx, unsigned int, off_t* off)
+              unsigned int sh_type, unsigned int reloc_shndx,
+              unsigned int, off_t* off)
 {
   *off = 0;
 
   if (!this->include_section(object, name, shdr))
     return NULL;
 
-  elfcpp::Elf_Word sh_type = shdr.get_sh_type();
-
   // In a relocatable link a grouped section must not be combined with
   // any other sections.
   Output_section* os;
   if (parameters->options().relocatable()
       && (shdr.get_sh_flags() & elfcpp::SHF_GROUP) != 0)
     {
+      // Some flags in the input section should not be automatically
+      // copied to the output section.
+      elfcpp::Elf_Xword sh_flags = (shdr.get_sh_flags()
+                                   & ~ elfcpp::SHF_COMPRESSED);
       name = this->namepool_.add(name, true, NULL);
-      os = this->make_output_section(name, sh_type, shdr.get_sh_flags(),
-                                    ORDER_INVALID, false);
+      os = this->make_output_section(name, sh_type, sh_flags, ORDER_INVALID,
+                                    false);
     }
   else
     {
-      os = this->choose_output_section(object, name, sh_type,
-                                      shdr.get_sh_flags(), true,
-                                      ORDER_INVALID, false);
+      // Get the section flags and mask out any flags that do not
+      // take part in section matching.
+      elfcpp::Elf_Xword sh_flags
+         = (this->get_output_section_flags(shdr.get_sh_flags())
+            & ~object->osabi().ignored_sh_flags());
+
+      // All ".text.unlikely.*" sections can be moved to a unique
+      // segment with --text-unlikely-segment option.
+      bool text_unlikely_segment
+         = (parameters->options().text_unlikely_segment()
+            && is_prefix_of(".text.unlikely",
+                            object->section_name(shndx).c_str()));
+      if (text_unlikely_segment)
+       {
+         Stringpool::Key name_key;
+         const char* os_name = this->namepool_.add(".text.unlikely", true,
+                                                   &name_key);
+         os = this->get_output_section(os_name, name_key, sh_type, sh_flags,
+                                       ORDER_INVALID, false);
+         // Map this output section to a unique segment.  This is done to
+         // separate "text" that is not likely to be executed from "text"
+         // that is likely executed.
+         os->set_is_unique_segment();
+       }
+      else
+       {
+         // Plugins can choose to place one or more subsets of sections in
+         // unique segments and this is done by mapping these section subsets
+         // to unique output sections.  Check if this section needs to be
+         // remapped to a unique output section.
+         Section_segment_map::iterator it
+           = this->section_segment_map_.find(Const_section_id(object, shndx));
+         if (it == this->section_segment_map_.end())
+           {
+             os = this->choose_output_section(object, name, sh_type,
+                                              sh_flags, true, ORDER_INVALID,
+                                              false, false, true);
+           }
+         else
+           {
+             // We know the name of the output section, directly call
+             // get_output_section here by-passing choose_output_section.
+             const char* os_name = it->second->name;
+             Stringpool::Key name_key;
+             os_name = this->namepool_.add(os_name, true, &name_key);
+             os = this->get_output_section(os_name, name_key, sh_type,
+                                           sh_flags, ORDER_INVALID, false);
+             if (!os->is_unique_segment())
+               {
+                 os->set_is_unique_segment();
+                 os->set_extra_segment_flags(it->second->flags);
+                 os->set_segment_alignment(it->second->align);
+               }
+           }
+         }
       if (os == NULL)
        return NULL;
     }
@@ -982,6 +1257,15 @@ Layout::layout(Sized_relobj_file<size, big_endian>* object, unsigned int shndx,
                  || strcmp(name, ".dtors") == 0))))
     os->set_must_sort_attached_input_sections();
 
+  // By default the GNU linker sorts some special text sections ahead
+  // of others.  We are compatible.
+  if (parameters->options().text_reorder()
+      && !this->script_options_->saw_sections_clause()
+      && !this->is_section_ordering_specified()
+      && !parameters->options().relocatable()
+      && Layout::special_ordering_of_input_section(name) >= 0)
+    os->set_must_sort_attached_input_sections();
+
   // If this is a .ctors or .ctors.* section being mapped to a
   // .init_array section, or a .dtors or .dtors.* section being mapped
   // to a .fini_array section, we will need to reverse the words if
@@ -1020,11 +1304,20 @@ Layout::layout(Sized_relobj_file<size, big_endian>* object, unsigned int shndx,
   return os;
 }
 
+// Maps section SECN to SEGMENT s.
+void
+Layout::insert_section_segment_map(Const_section_id secn,
+                                  Unique_segment_info *s)
+{
+  gold_assert(this->unique_segment_for_sections_specified_);
+  this->section_segment_map_[secn] = s;
+}
+
 // Handle a relocation section when doing a relocatable link.
 
 template<int size, bool big_endian>
 Output_section*
-Layout::layout_reloc(Sized_relobj_file<size, big_endian>* object,
+Layout::layout_reloc(Sized_relobj_file<size, big_endian>*,
                     unsigned int,
                     const elfcpp::Shdr<size, big_endian>& shdr,
                     Output_section* data_section,
@@ -1044,24 +1337,19 @@ Layout::layout_reloc(Sized_relobj_file<size, big_endian>* object,
     gold_unreachable();
   name += data_section->name();
 
-  // In a relocatable link relocs for a grouped section must not be
-  // combined with other reloc sections.
-  Output_section* os;
-  if (!parameters->options().relocatable()
-      || (data_section->flags() & elfcpp::SHF_GROUP) == 0)
-    os = this->choose_output_section(object, name.c_str(), sh_type,
-                                    shdr.get_sh_flags(), false,
-                                    ORDER_INVALID, false);
-  else
+  // If the output data section already has a reloc section, use that;
+  // otherwise, make a new one.
+  Output_section* os = data_section->reloc_section();
+  if (os == NULL)
     {
       const char* n = this->namepool_.add(name.c_str(), true, NULL);
       os = this->make_output_section(n, sh_type, shdr.get_sh_flags(),
                                     ORDER_INVALID, false);
+      os->set_should_link_to_symtab();
+      os->set_info_section(data_section);
+      data_section->set_reloc_section(os);
     }
 
-  os->set_should_link_to_symtab();
-  os->set_info_section(data_section);
-
   Output_section_data* posd;
   if (sh_type == elfcpp::SHT_REL)
     {
@@ -1151,8 +1439,11 @@ Layout::layout_eh_frame(Sized_relobj_file<size, big_endian>* object,
                        unsigned int reloc_shndx, unsigned int reloc_type,
                        off_t* off)
 {
+  const unsigned int unwind_section_type =
+      parameters->target().unwind_section_type();
+
   gold_assert(shdr.get_sh_type() == elfcpp::SHT_PROGBITS
-             || shdr.get_sh_type() == elfcpp::SHT_X86_64_UNWIND);
+             || shdr.get_sh_type() == unwind_section_type);
   gold_assert((shdr.get_sh_flags() & elfcpp::SHF_ALLOC) != 0);
 
   Output_section* os = this->make_eh_frame_section(object);
@@ -1163,15 +1454,21 @@ Layout::layout_eh_frame(Sized_relobj_file<size, big_endian>* object,
 
   elfcpp::Elf_Xword orig_flags = os->flags();
 
-  if (!parameters->incremental()
-      && this->eh_frame_data_->add_ehframe_input_section(object,
-                                                        symbols,
-                                                        symbols_size,
-                                                        symbol_names,
-                                                        symbol_names_size,
-                                                        shndx,
-                                                        reloc_shndx,
-                                                        reloc_type))
+  Eh_frame::Eh_frame_section_disposition disp =
+      Eh_frame::EH_UNRECOGNIZED_SECTION;
+  if (!parameters->incremental())
+    {
+      disp = this->eh_frame_data_->add_ehframe_input_section(object,
+                                                            symbols,
+                                                            symbols_size,
+                                                            symbol_names,
+                                                            symbol_names_size,
+                                                            shndx,
+                                                            reloc_shndx,
+                                                            reloc_type);
+    }
+
+  if (disp == Eh_frame::EH_OPTIMIZABLE_SECTION)
     {
       os->update_flags_for_input_section(shdr.get_sh_flags());
 
@@ -1183,35 +1480,49 @@ Layout::layout_eh_frame(Sized_relobj_file<size, big_endian>* object,
          os->set_order(ORDER_RELRO);
        }
 
-      // 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;
+      return os;
     }
-  else
+
+  if (disp == Eh_frame::EH_END_MARKER_SECTION && !this->added_eh_frame_data_)
     {
-      // We couldn't handle this .eh_frame section for some reason.
-      // Add it as a normal section.
-      bool saw_sections_clause = this->script_options_->saw_sections_clause();
-      *off = os->add_input_section(this, object, shndx, ".eh_frame", shdr,
-                                  reloc_shndx, saw_sections_clause);
-      this->have_added_input_section_ = true;
+      // We found the end marker section, 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 crtbeginT.o winds up at the start of
+      // the output section.
+      os->add_output_section_data(this->eh_frame_data_);
+      this->added_eh_frame_data_ = true;
+     }
 
-      if ((orig_flags & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR))
-         != (os->flags() & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR)))
-       os->set_order(this->default_section_order(os, false));
-    }
+  // We couldn't handle this .eh_frame section for some reason.
+  // Add it as a normal section.
+  bool saw_sections_clause = this->script_options_->saw_sections_clause();
+  *off = os->add_input_section(this, object, shndx, ".eh_frame", shdr,
+                              reloc_shndx, saw_sections_clause);
+  this->have_added_input_section_ = true;
+
+  if ((orig_flags & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR))
+      != (os->flags() & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR)))
+    os->set_order(this->default_section_order(os, false));
 
   return os;
 }
 
+void
+Layout::finalize_eh_frame_section()
+{
+  // If we never found an end marker section, we need to add the
+  // optimized eh sections to the output section now.
+  if (!parameters->incremental()
+      && this->eh_frame_section_ != NULL
+      && !this->added_eh_frame_data_)
+    {
+      this->eh_frame_section_->add_output_section_data(this->eh_frame_data_);
+      this->added_eh_frame_data_ = true;
+    }
+}
+
 // Create and return the magic .eh_frame section.  Create
 // .eh_frame_hdr also if appropriate.  OBJECT is the object with the
 // input .eh_frame section; it may be NULL.
@@ -1219,12 +1530,14 @@ Layout::layout_eh_frame(Sized_relobj_file<size, big_endian>* object,
 Output_section*
 Layout::make_eh_frame_section(const Relobj* object)
 {
-  // FIXME: On x86_64, this could use SHT_X86_64_UNWIND rather than
-  // SHT_PROGBITS.
+  const unsigned int unwind_section_type =
+      parameters->target().unwind_section_type();
+
   Output_section* os = this->choose_output_section(object, ".eh_frame",
-                                                  elfcpp::SHT_PROGBITS,
+                                                  unwind_section_type,
                                                   elfcpp::SHF_ALLOC, false,
-                                                  ORDER_EHFRAME, false);
+                                                  ORDER_EHFRAME, false, false,
+                                                  false);
   if (os == NULL)
     return NULL;
 
@@ -1239,9 +1552,10 @@ Layout::make_eh_frame_section(const Relobj* object)
        {
          Output_section* hdr_os =
            this->choose_output_section(NULL, ".eh_frame_hdr",
-                                       elfcpp::SHT_PROGBITS,
+                                       unwind_section_type,
                                        elfcpp::SHF_ALLOC, false,
-                                       ORDER_EHFRAME, false);
+                                       ORDER_EHFRAME, false, false,
+                                       false);
 
          if (hdr_os != NULL)
            {
@@ -1292,6 +1606,52 @@ Layout::add_eh_frame_for_plt(Output_data* plt, const unsigned char* cie_data,
     }
 }
 
+// Remove all post-map .eh_frame information for a PLT.
+
+void
+Layout::remove_eh_frame_for_plt(Output_data* plt, const unsigned char* cie_data,
+                               size_t cie_length)
+{
+  if (parameters->incremental())
+    {
+      // FIXME: Maybe this could work some day....
+      return;
+    }
+  this->eh_frame_data_->remove_ehframe_for_plt(plt, cie_data, cie_length);
+}
+
+// Scan a .debug_info or .debug_types section, and add summary
+// information to the .gdb_index section.
+
+template<int size, bool big_endian>
+void
+Layout::add_to_gdb_index(bool is_type_unit,
+                        Sized_relobj<size, big_endian>* object,
+                        const unsigned char* symbols,
+                        off_t symbols_size,
+                        unsigned int shndx,
+                        unsigned int reloc_shndx,
+                        unsigned int reloc_type)
+{
+  if (this->gdb_index_data_ == NULL)
+    {
+      Output_section* os = this->choose_output_section(NULL, ".gdb_index",
+                                                      elfcpp::SHT_PROGBITS, 0,
+                                                      false, ORDER_INVALID,
+                                                      false, false, false);
+      if (os == NULL)
+       return;
+
+      this->gdb_index_data_ = new Gdb_index(os);
+      os->add_output_section_data(this->gdb_index_data_);
+      os->set_after_input_sections();
+    }
+
+  this->gdb_index_data_->scan_debug_info(is_type_unit, object, symbols,
+                                        symbols_size, shndx, reloc_shndx,
+                                        reloc_type);
+}
+
 // Add POSD to an output section using NAME, TYPE, and FLAGS.  Return
 // the output section.
 
@@ -1302,7 +1662,8 @@ Layout::add_output_section_data(const char* name, elfcpp::Elf_Word type,
                                Output_section_order order, bool is_relro)
 {
   Output_section* os = this->choose_output_section(NULL, name, type, flags,
-                                                  false, order, is_relro);
+                                                  false, order, is_relro,
+                                                  false, false);
   if (os != NULL)
     os->add_output_section_data(posd);
   return os;
@@ -1338,22 +1699,22 @@ Layout::make_output_section(const char* name, elfcpp::Elf_Word type,
     os = new Output_compressed_section(&parameters->options(), name, type,
                                       flags);
   else if ((flags & elfcpp::SHF_ALLOC) == 0
-           && parameters->options().strip_debug_non_line()
-           && strcmp(".debug_abbrev", name) == 0)
+          && parameters->options().strip_debug_non_line()
+          && strcmp(".debug_abbrev", name) == 0)
     {
       os = this->debug_abbrev_ = new Output_reduced_debug_abbrev_section(
-          name, type, flags);
+         name, type, flags);
       if (this->debug_info_)
-        this->debug_info_->set_abbreviations(this->debug_abbrev_);
+       this->debug_info_->set_abbreviations(this->debug_abbrev_);
     }
   else if ((flags & elfcpp::SHF_ALLOC) == 0
-           && parameters->options().strip_debug_non_line()
-           && strcmp(".debug_info", name) == 0)
+          && parameters->options().strip_debug_non_line()
+          && strcmp(".debug_info", name) == 0)
     {
       os = this->debug_info_ = new Output_reduced_debug_info_section(
-          name, type, flags);
+         name, type, flags);
       if (this->debug_abbrev_)
-        this->debug_info_->set_abbreviations(this->debug_abbrev_);
+       this->debug_info_->set_abbreviations(this->debug_abbrev_);
     }
   else
     {
@@ -1384,7 +1745,9 @@ Layout::make_output_section(const char* name, elfcpp::Elf_Word type,
     {
       if (type == elfcpp::SHT_PROGBITS)
        {
-         if (strcmp(name, ".data.rel.ro") == 0)
+         if ((flags & elfcpp::SHF_TLS) != 0)
+           is_relro = true;
+         else if (strcmp(name, ".data.rel.ro") == 0)
            is_relro = true;
          else if (strcmp(name, ".data.rel.ro.local") == 0)
            {
@@ -1426,6 +1789,21 @@ Layout::make_output_section(const char* name, elfcpp::Elf_Word type,
                  || strcmp(name, ".dtors") == 0))))
     os->set_may_sort_attached_input_sections();
 
+  // The GNU linker by default sorts .text.{unlikely,exit,startup,hot}
+  // sections before other .text sections.  We are compatible.  We
+  // need to know that this might happen before we attach any input
+  // sections.
+  if (parameters->options().text_reorder()
+      && !this->script_options_->saw_sections_clause()
+      && !this->is_section_ordering_specified()
+      && !parameters->options().relocatable()
+      && strcmp(name, ".text") == 0)
+    os->set_may_sort_attached_input_sections();
+
+  // GNU linker sorts section by name with --sort-section=name.
+  if (strcmp(parameters->options().sort_section(), "name") == 0)
+      os->set_must_sort_attached_input_sections();
+
   // Check for .stab*str sections, as .stab* sections need to link to
   // them.
   if (type == elfcpp::SHT_STRTAB
@@ -1456,18 +1834,18 @@ Layout::make_output_section(const char* name, elfcpp::Elf_Word type,
       // a minimum size, so we must prevent allocations from the
       // free list that leave a hole smaller than the minimum.
       if (strcmp(name, ".debug_info") == 0)
-        os->set_free_space_fill(new Output_fill_debug_info(false));
+       os->set_free_space_fill(new Output_fill_debug_info(false));
       else if (strcmp(name, ".debug_types") == 0)
-        os->set_free_space_fill(new Output_fill_debug_info(true));
+       os->set_free_space_fill(new Output_fill_debug_info(true));
       else if (strcmp(name, ".debug_line") == 0)
-        os->set_free_space_fill(new Output_fill_debug_line());
+       os->set_free_space_fill(new Output_fill_debug_line());
     }
 
   // 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);
+    this->attach_section_to_segment(&parameters->target(), os);
 
   return os;
 }
@@ -1525,6 +1903,19 @@ Layout::default_section_order(Output_section* os, bool is_relro_local)
            return ORDER_INIT;
          else if (strcmp(os->name(), ".fini") == 0)
            return ORDER_FINI;
+         else if (parameters->options().keep_text_section_prefix())
+           {
+             // -z,keep-text-section-prefix introduces additional
+             // output sections.
+             if (strcmp(os->name(), ".text.hot") == 0)
+               return ORDER_TEXT_HOT;
+             else if (strcmp(os->name(), ".text.startup") == 0)
+               return ORDER_TEXT_STARTUP;
+             else if (strcmp(os->name(), ".text.exit") == 0)
+               return ORDER_TEXT_EXIT;
+             else if (strcmp(os->name(), ".text.unlikely") == 0)
+               return ORDER_TEXT_UNLIKELY;
+           }
        }
       return is_execinstr ? ORDER_TEXT : ORDER_READONLY;
     }
@@ -1544,12 +1935,12 @@ Layout::default_section_order(Output_section* os, bool is_relro_local)
 // seen all the input sections.
 
 void
-Layout::attach_sections_to_segments()
+Layout::attach_sections_to_segments(const Target* target)
 {
   for (Section_list::iterator p = this->section_list_.begin();
        p != this->section_list_.end();
        ++p)
-    this->attach_section_to_segment(*p);
+    this->attach_section_to_segment(target, *p);
 
   this->sections_are_attached_ = true;
 }
@@ -1557,18 +1948,19 @@ Layout::attach_sections_to_segments()
 // Attach an output section to a segment.
 
 void
-Layout::attach_section_to_segment(Output_section* os)
+Layout::attach_section_to_segment(const Target* target, 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);
+    this->attach_allocated_section_to_segment(target, os);
 }
 
 // Attach an allocated output section to a segment.
 
 void
-Layout::attach_allocated_section_to_segment(Output_section* os)
+Layout::attach_allocated_section_to_segment(const Target* target,
+                                           Output_section* os)
 {
   elfcpp::Elf_Xword flags = os->flags();
   gold_assert((flags & elfcpp::SHF_ALLOC) != 0);
@@ -1587,6 +1979,10 @@ Layout::attach_allocated_section_to_segment(Output_section* os)
 
   elfcpp::Elf_Word seg_flags = Layout::section_flags_to_segment(flags);
 
+  // If this output section's segment has extra flags that need to be set,
+  // coming from a linker plugin, do that.
+  seg_flags |= os->extra_segment_flags();
+
   // Check for --section-start.
   uint64_t addr;
   bool is_address_set = parameters->options().section_start(os->name(), &addr);
@@ -1599,79 +1995,97 @@ Layout::attach_allocated_section_to_segment(Output_section* os)
   // have to use a linker script.
 
   Segment_list::const_iterator p;
-  for (p = this->segment_list_.begin();
-       p != this->segment_list_.end();
-       ++p)
+  if (!os->is_unique_segment())
     {
-      if ((*p)->type() != elfcpp::PT_LOAD)
-       continue;
-      if (!parameters->options().omagic()
-         && ((*p)->flags() & elfcpp::PF_W) != (seg_flags & elfcpp::PF_W))
-       continue;
-      if (parameters->options().rosegment()
-          && ((*p)->flags() & elfcpp::PF_X) != (seg_flags & elfcpp::PF_X))
-        continue;
-      // If -Tbss was specified, we need to separate the data and BSS
-      // segments.
-      if (parameters->options().user_set_Tbss())
+      for (p = this->segment_list_.begin();
+          p != this->segment_list_.end();
+          ++p)
        {
-         if ((os->type() == elfcpp::SHT_NOBITS)
-             == (*p)->has_any_data_sections())
+         if ((*p)->type() != elfcpp::PT_LOAD)
            continue;
-       }
-      if (os->is_large_data_section() && !(*p)->is_large_data_segment())
-       continue;
-
-      if (is_address_set)
-       {
-         if ((*p)->are_addresses_set())
+         if ((*p)->is_unique_segment())
+           continue;
+         if (!parameters->options().omagic()
+             && ((*p)->flags() & elfcpp::PF_W) != (seg_flags & elfcpp::PF_W))
+           continue;
+         if ((target->isolate_execinstr() || parameters->options().rosegment())
+             && ((*p)->flags() & elfcpp::PF_X) != (seg_flags & elfcpp::PF_X))
            continue;
+         // If -Tbss was specified, we need to separate the data and BSS
+         // segments.
+         if (parameters->options().user_set_Tbss())
+           {
+             if ((os->type() == elfcpp::SHT_NOBITS)
+                 == (*p)->has_any_data_sections())
+               continue;
+           }
+         if (os->is_large_data_section() && !(*p)->is_large_data_segment())
+           continue;
+
+         if (is_address_set)
+           {
+             if ((*p)->are_addresses_set())
+               continue;
 
-         (*p)->add_initial_output_data(os);
-         (*p)->update_flags_for_output_section(seg_flags);
-         (*p)->set_addresses(addr, addr);
+             (*p)->add_initial_output_data(os);
+             (*p)->update_flags_for_output_section(seg_flags);
+             (*p)->set_addresses(addr, addr);
+             break;
+           }
+
+         (*p)->add_output_section_to_load(this, os, seg_flags);
          break;
        }
-
-      (*p)->add_output_section_to_load(this, os, seg_flags);
-      break;
     }
 
-  if (p == this->segment_list_.end())
+  if (p == this->segment_list_.end()
+      || os->is_unique_segment())
     {
       Output_segment* oseg = this->make_output_segment(elfcpp::PT_LOAD,
-                                                       seg_flags);
+                                                      seg_flags);
       if (os->is_large_data_section())
        oseg->set_is_large_data_segment();
       oseg->add_output_section_to_load(this, os, seg_flags);
       if (is_address_set)
        oseg->set_addresses(addr, addr);
+      // Check if segment should be marked unique.  For segments marked
+      // unique by linker plugins, set the new alignment if specified.
+      if (os->is_unique_segment())
+       {
+         oseg->set_is_unique_segment();
+         if (os->segment_alignment() != 0)
+           oseg->set_minimum_p_align(os->segment_alignment());
+       }
     }
 
   // If we see a loadable SHT_NOTE section, we create a PT_NOTE
   // segment.
   if (os->type() == elfcpp::SHT_NOTE)
     {
+      uint64_t os_align = os->addralign();
+
       // See if we already have an equivalent PT_NOTE segment.
       for (p = this->segment_list_.begin();
-           p != segment_list_.end();
-           ++p)
-        {
-          if ((*p)->type() == elfcpp::PT_NOTE
-              && (((*p)->flags() & elfcpp::PF_W)
-                  == (seg_flags & elfcpp::PF_W)))
-            {
-              (*p)->add_output_section_to_nonload(os, seg_flags);
-              break;
-            }
-        }
+          p != segment_list_.end();
+          ++p)
+       {
+         if ((*p)->type() == elfcpp::PT_NOTE
+             && (*p)->align() == os_align
+             && (((*p)->flags() & elfcpp::PF_W)
+                 == (seg_flags & elfcpp::PF_W)))
+           {
+             (*p)->add_output_section_to_nonload(os, seg_flags);
+             break;
+           }
+       }
 
       if (p == this->segment_list_.end())
-        {
-          Output_segment* oseg = this->make_output_segment(elfcpp::PT_NOTE,
-                                                           seg_flags);
-          oseg->add_output_section_to_nonload(os, seg_flags);
-        }
+       {
+         Output_segment* oseg = this->make_output_segment(elfcpp::PT_NOTE,
+                                                          seg_flags);
+         oseg->add_output_section_to_nonload(os, seg_flags);
+         oseg->set_align(os_align);
+       }
     }
 
   // If we see a loadable SHF_TLS section, we create a PT_TLS
@@ -1776,21 +2190,252 @@ Layout::layout_gnu_stack(bool seen_gnu_stack, uint64_t gnu_stack_flags,
       if ((gnu_stack_flags & elfcpp::SHF_EXECINSTR) != 0)
        {
          this->input_requires_executable_stack_ = true;
-         if (parameters->options().warn_execstack()
-             || parameters->options().is_stack_executable())
+         if (parameters->options().warn_execstack())
            gold_warning(_("%s: requires executable stack"),
                         obj->name().c_str());
        }
     }
 }
 
+// Read a value with given size and endianness.
+
+static inline uint64_t
+read_sized_value(size_t size, const unsigned char* buf, bool is_big_endian,
+                const Object* object)
+{
+  uint64_t val = 0;
+  if (size == 4)
+    {
+      if (is_big_endian)
+       val = elfcpp::Swap<32, true>::readval(buf);
+      else
+       val = elfcpp::Swap<32, false>::readval(buf);
+    }
+  else if (size == 8)
+    {
+      if (is_big_endian)
+       val = elfcpp::Swap<64, true>::readval(buf);
+      else
+       val = elfcpp::Swap<64, false>::readval(buf);
+    }
+  else
+    {
+      gold_warning(_("%s: in .note.gnu.property section, "
+                    "pr_datasz must be 4 or 8"),
+                  object->name().c_str());
+    }
+  return val;
+}
+
+// Write a value with given size and endianness.
+
+static inline void
+write_sized_value(uint64_t value, size_t size, unsigned char* buf,
+                 bool is_big_endian)
+{
+  if (size == 4)
+    {
+      if (is_big_endian)
+       elfcpp::Swap<32, true>::writeval(buf, static_cast<uint32_t>(value));
+      else
+       elfcpp::Swap<32, false>::writeval(buf, static_cast<uint32_t>(value));
+    }
+  else if (size == 8)
+    {
+      if (is_big_endian)
+       elfcpp::Swap<64, true>::writeval(buf, value);
+      else
+       elfcpp::Swap<64, false>::writeval(buf, value);
+    }
+  else
+    {
+      // We will have already complained about this.
+    }
+}
+
+// Handle the .note.gnu.property section at layout time.
+
+void
+Layout::layout_gnu_property(unsigned int note_type,
+                           unsigned int pr_type,
+                           size_t pr_datasz,
+                           const unsigned char* pr_data,
+                           const Object* object)
+{
+  // We currently support only the one note type.
+  gold_assert(note_type == elfcpp::NT_GNU_PROPERTY_TYPE_0);
+
+  if (pr_type >= elfcpp::GNU_PROPERTY_LOPROC
+      && pr_type < elfcpp::GNU_PROPERTY_HIPROC)
+    {
+      // Target-dependent property value; call the target to record.
+      const int size = parameters->target().get_size();
+      const bool is_big_endian = parameters->target().is_big_endian();
+      if (size == 32)
+       {
+         if (is_big_endian)
+           {
+#ifdef HAVE_TARGET_32_BIG
+             parameters->sized_target<32, true>()->
+                 record_gnu_property(note_type, pr_type, pr_datasz, pr_data,
+                                     object);
+#else
+             gold_unreachable();
+#endif
+           }
+         else
+           {
+#ifdef HAVE_TARGET_32_LITTLE
+             parameters->sized_target<32, false>()->
+                 record_gnu_property(note_type, pr_type, pr_datasz, pr_data,
+                                     object);
+#else
+             gold_unreachable();
+#endif
+           }
+       }
+      else if (size == 64)
+       {
+         if (is_big_endian)
+           {
+#ifdef HAVE_TARGET_64_BIG
+             parameters->sized_target<64, true>()->
+                 record_gnu_property(note_type, pr_type, pr_datasz, pr_data,
+                                     object);
+#else
+             gold_unreachable();
+#endif
+           }
+         else
+           {
+#ifdef HAVE_TARGET_64_LITTLE
+             parameters->sized_target<64, false>()->
+                 record_gnu_property(note_type, pr_type, pr_datasz, pr_data,
+                                     object);
+#else
+             gold_unreachable();
+#endif
+           }
+       }
+      else
+       gold_unreachable();
+      return;
+    }
+
+  Gnu_properties::iterator pprop = this->gnu_properties_.find(pr_type);
+  if (pprop == this->gnu_properties_.end())
+    {
+      Gnu_property prop;
+      prop.pr_datasz = pr_datasz;
+      prop.pr_data = new unsigned char[pr_datasz];
+      memcpy(prop.pr_data, pr_data, pr_datasz);
+      this->gnu_properties_[pr_type] = prop;
+    }
+  else
+    {
+      const bool is_big_endian = parameters->target().is_big_endian();
+      switch (pr_type)
+       {
+       case elfcpp::GNU_PROPERTY_STACK_SIZE:
+         // Record the maximum value seen.
+         {
+           uint64_t val1 = read_sized_value(pprop->second.pr_datasz,
+                                            pprop->second.pr_data,
+                                            is_big_endian, object);
+           uint64_t val2 = read_sized_value(pr_datasz, pr_data,
+                                            is_big_endian, object);
+           if (val2 > val1)
+             write_sized_value(val2, pprop->second.pr_datasz,
+                               pprop->second.pr_data, is_big_endian);
+         }
+         break;
+       case elfcpp::GNU_PROPERTY_NO_COPY_ON_PROTECTED:
+         // No data to merge.
+         break;
+       default:
+         gold_warning(_("%s: unknown program property type %d "
+                        "in .note.gnu.property section"),
+                      object->name().c_str(), pr_type);
+       }
+    }
+}
+
+// Merge per-object properties with program properties.
+// This lets the target identify objects that are missing certain
+// properties, in cases where properties must be ANDed together.
+
+void
+Layout::merge_gnu_properties(const Object* object)
+{
+  const int size = parameters->target().get_size();
+  const bool is_big_endian = parameters->target().is_big_endian();
+  if (size == 32)
+    {
+      if (is_big_endian)
+       {
+#ifdef HAVE_TARGET_32_BIG
+         parameters->sized_target<32, true>()->merge_gnu_properties(object);
+#else
+         gold_unreachable();
+#endif
+       }
+      else
+       {
+#ifdef HAVE_TARGET_32_LITTLE
+         parameters->sized_target<32, false>()->merge_gnu_properties(object);
+#else
+         gold_unreachable();
+#endif
+       }
+    }
+  else if (size == 64)
+    {
+      if (is_big_endian)
+       {
+#ifdef HAVE_TARGET_64_BIG
+         parameters->sized_target<64, true>()->merge_gnu_properties(object);
+#else
+         gold_unreachable();
+#endif
+       }
+      else
+       {
+#ifdef HAVE_TARGET_64_LITTLE
+         parameters->sized_target<64, false>()->merge_gnu_properties(object);
+#else
+         gold_unreachable();
+#endif
+       }
+    }
+  else
+    gold_unreachable();
+}
+
+// Add a target-specific property for the output .note.gnu.property section.
+
+void
+Layout::add_gnu_property(unsigned int note_type,
+                        unsigned int pr_type,
+                        size_t pr_datasz,
+                        const unsigned char* pr_data)
+{
+  gold_assert(note_type == elfcpp::NT_GNU_PROPERTY_TYPE_0);
+
+  Gnu_property prop;
+  prop.pr_datasz = pr_datasz;
+  prop.pr_data = new unsigned char[pr_datasz];
+  memcpy(prop.pr_data, pr_data, pr_datasz);
+  this->gnu_properties_[pr_type] = prop;
+}
+
 // Create automatic note sections.
 
 void
 Layout::create_notes()
 {
+  this->create_gnu_properties_note();
   this->create_gold_note();
-  this->create_executable_stack_info();
+  this->create_stack_segment();
   this->create_build_id();
 }
 
@@ -1808,7 +2453,7 @@ Layout::create_initial_dynamic_sections(Symbol_table* symtab)
                                                       (elfcpp::SHF_ALLOC
                                                        | elfcpp::SHF_WRITE),
                                                       false, ORDER_RELRO,
-                                                      true);
+                                                      true, false, false);
 
   // A linker script may discard .dynamic, so check for NULL.
   if (this->dynamic_section_ != NULL)
@@ -1833,6 +2478,7 @@ Layout::create_initial_dynamic_sections(Symbol_table* symtab)
 void
 Layout::define_section_symbols(Symbol_table* symtab)
 {
+  const elfcpp::STV visibility = parameters->options().start_stop_visibility_enum();
   for (Section_list::const_iterator p = this->section_list_.begin();
        p != this->section_list_.end();
        ++p)
@@ -1842,9 +2488,9 @@ Layout::define_section_symbols(Symbol_table* symtab)
        {
          const std::string name_string(name);
          const std::string start_name(cident_section_start_prefix
-                                       + name_string);
+                                      + name_string);
          const std::string stop_name(cident_section_stop_prefix
-                                      + name_string);
+                                     + name_string);
 
          symtab->define_in_output_data(start_name.c_str(),
                                        NULL, // version
@@ -1854,7 +2500,7 @@ Layout::define_section_symbols(Symbol_table* symtab)
                                        0, // symsize
                                        elfcpp::STT_NOTYPE,
                                        elfcpp::STB_GLOBAL,
-                                       elfcpp::STV_DEFAULT,
+                                       visibility,
                                        0, // nonvis
                                        false, // offset_is_from_end
                                        true); // only_if_ref
@@ -1867,7 +2513,7 @@ Layout::define_section_symbols(Symbol_table* symtab)
                                        0, // symsize
                                        elfcpp::STT_NOTYPE,
                                        elfcpp::STB_GLOBAL,
-                                       elfcpp::STV_DEFAULT,
+                                       visibility,
                                        0, // nonvis
                                        true, // offset_is_from_end
                                        true); // only_if_ref
@@ -1910,7 +2556,7 @@ Layout::define_group_signatures(Symbol_table* symtab)
 // necessary.
 
 Output_segment*
-Layout::find_first_load_seg()
+Layout::find_first_load_seg(const Target* target)
 {
   Output_segment* best = NULL;
   for (Segment_list::const_iterator p = this->segment_list_.begin();
@@ -1920,11 +2566,13 @@ Layout::find_first_load_seg()
       if ((*p)->type() == elfcpp::PT_LOAD
          && ((*p)->flags() & elfcpp::PF_R) != 0
          && (parameters->options().omagic()
-             || ((*p)->flags() & elfcpp::PF_W) == 0))
-        {
-          if (best == NULL || this->segment_precedes(*p, best))
-            best = *p;
-        }
+             || ((*p)->flags() & elfcpp::PF_W) == 0)
+         && (!target->isolate_execinstr()
+             || ((*p)->flags() & elfcpp::PF_X) == 0))
+       {
+         if (best == NULL || this->segment_precedes(*p, best))
+           best = *p;
+       }
     }
   if (best != NULL)
     return best;
@@ -1982,10 +2630,10 @@ Layout::restore_segments(const Segment_states* segment_states)
            this->relro_segment_ = segment;
 
          ++list_iter;
-       } 
+       }
       else
        {
-         list_iter = this->segment_list_.erase(list_iter); 
+         list_iter = this->segment_list_.erase(list_iter);
          // This is a segment created during section layout.  It should be
          // safe to remove it since we should have removed all pointers to it.
          delete segment;
@@ -2018,7 +2666,7 @@ Layout::clean_up_after_relaxation()
 
       (*p)->reset_address_and_file_offset();
     }
-  
+
   // Reset special output object address and file offsets.
   for (Data_list::iterator p = this->special_output_list_.begin();
        p != this->special_output_list_.end();
@@ -2032,7 +2680,21 @@ Layout::clean_up_after_relaxation()
        p != this->script_output_section_data_list_.end();
        ++p)
     delete *p;
-  this->script_output_section_data_list_.clear(); 
+  this->script_output_section_data_list_.clear();
+
+  // Special-case fill output objects are recreated each time through
+  // the relaxation loop.
+  this->reset_relax_output();
+}
+
+void
+Layout::reset_relax_output()
+{
+  for (Data_list::const_iterator p = this->relax_output_list_.begin();
+       p != this->relax_output_list_.end();
+       ++p)
+    delete *p;
+  this->relax_output_list_.clear();
 }
 
 // Prepare for relaxation.
@@ -2055,16 +2717,33 @@ Layout::prepare_for_relaxation()
 
   if (is_debugging_enabled(DEBUG_RELAXATION))
     this->relaxation_debug_check_->check_output_data_for_reset_values(
-        this->section_list_, this->special_output_list_);
+       this->section_list_, this->special_output_list_,
+       this->relax_output_list_);
 
   // Also enable recording of output section data from scripts.
   this->record_output_section_data_from_script_ = true;
 }
 
+// If the user set the address of the text segment, that may not be
+// compatible with putting the segment headers and file headers into
+// that segment.  For isolate_execinstr() targets, it's the rodata
+// segment rather than text where we might put the headers.
+static inline bool
+load_seg_unusable_for_headers(const Target* target)
+{
+  const General_options& options = parameters->options();
+  if (target->isolate_execinstr())
+    return (options.user_set_Trodata_segment()
+           && options.Trodata_segment() % target->abi_pagesize() != 0);
+  else
+    return (options.user_set_Ttext()
+           && options.Ttext() % target->abi_pagesize() != 0);
+}
+
 // Relaxation loop body:  If target has no relaxation, this runs only once
 // Otherwise, the target relaxation hook is called at the end of
 // each iteration.  If the hook returns true, it means re-layout of
-// section is required.  
+// section is required.
 //
 // The number of segments created by a linking script without a PHDRS
 // clause may be affected by section sizes and alignments.  There is
@@ -2074,8 +2753,8 @@ Layout::prepare_for_relaxation()
 // layout.  In order to be able to restart the section layout, we keep
 // a copy of the segment list right before the relaxation loop and use
 // that to restore the segments.
-// 
-// PASS is the current relaxation pass number. 
+//
+// PASS is the current relaxation pass number.
 // SYMTAB is a symbol table.
 // PLOAD_SEG is the address of a pointer for the load segment.
 // PHDR_SEG is a pointer to the PHDR segment.
@@ -2107,17 +2786,13 @@ Layout::relaxation_loop_body(
   else if (parameters->options().relocatable())
     load_seg = NULL;
   else
-    load_seg = this->find_first_load_seg();
+    load_seg = this->find_first_load_seg(target);
 
   if (parameters->options().oformat_enum()
       != General_options::OBJECT_FORMAT_ELF)
     load_seg = NULL;
 
-  // If the user set the address of the text segment, that may not be
-  // compatible with putting the segment headers and file headers into
-  // that segment.
-  if (parameters->options().user_set_Ttext()
-      && parameters->options().Ttext() % target->common_pagesize() != 0)
+  if (load_seg_unusable_for_headers(target))
     {
       load_seg = NULL;
       phdr_seg = NULL;
@@ -2164,9 +2839,9 @@ Layout::relaxation_loop_body(
          load_seg->add_initial_output_data(z);
        }
       if (load_seg != NULL)
-        load_seg->add_initial_output_data(segment_headers);
+       load_seg->add_initial_output_data(segment_headers);
       if (phdr_seg != NULL)
-        phdr_seg->add_initial_output_data(segment_headers);
+       phdr_seg->add_initial_output_data(segment_headers);
     }
 
   // Lay out the file header.
@@ -2207,7 +2882,7 @@ Layout::relaxation_loop_body(
   return off;
 }
 
-// Search the list of patterns and find the postion of the given section
+// Search the list of patterns and find the position of the given section
 // name in the output section.  If the section name matches a glob
 // pattern and a non-glob name, then the non-glob position takes
 // precedence.  Return 0 if no match is found.
@@ -2227,11 +2902,11 @@ Layout::find_section_order_index(const std::string& section_name)
        ++it)
     {
        if (fnmatch((*it).c_str(), section_name.c_str(), FNM_NOESCAPE) == 0)
-         {
-           map_it = this->input_section_position_.find(*it);
-           gold_assert(map_it != this->input_section_position_.end());
-           return map_it->second;
-         }
+        {
+          map_it = this->input_section_position_.find(*it);
+          gold_assert(map_it != this->input_section_position_.end());
+          return map_it->second;
+        }
     }
   return 0;
 }
@@ -2249,7 +2924,9 @@ Layout::read_layout_from_file()
   in.open(filename);
   if (!in)
     gold_fatal(_("unable to open --section-ordering-file file %s: %s"),
-               filename, strerror(errno));
+              filename, strerror(errno));
+
+  File_read::record_file_read(filename);
 
   std::getline(in, line);   // this chops off the trailing \n, if any
   unsigned int position = 1;
@@ -2258,17 +2935,17 @@ Layout::read_layout_from_file()
   while (in)
     {
       if (!line.empty() && line[line.length() - 1] == '\r')   // Windows
-        line.resize(line.length() - 1);
+       line.resize(line.length() - 1);
       // Ignore comments, beginning with '#'
       if (line[0] == '#')
-        {
-          std::getline(in, line);
-          continue;
-        }
+       {
+         std::getline(in, line);
+         continue;
+       }
       this->input_section_position_[line] = position;
       // Store all glob patterns in a vector.
       if (is_wildcard_string(line.c_str()))
-        this->input_section_glob_.push_back(line);
+       this->input_section_glob_.push_back(line);
       position++;
       std::getline(in, line);
     }
@@ -2310,6 +2987,9 @@ off_t
 Layout::finalize(const Input_objects* input_objects, Symbol_table* symtab,
                 Target* target, const Task* task)
 {
+  unsigned int local_dynamic_count = 0;
+  unsigned int forced_local_dynamic_count = 0;
+
   target->finalize_sections(this, input_objects, symtab);
 
   this->count_local_symbols(task, input_objects);
@@ -2330,11 +3010,12 @@ Layout::finalize(const Input_objects* input_objects, Symbol_table* symtab,
       // Create the dynamic symbol table, including the hash table.
       Output_section* dynstr;
       std::vector<Symbol*> dynamic_symbols;
-      unsigned int local_dynamic_count;
       Versions versions(*this->script_options()->version_script_info(),
-                        &this->dynpool_);
+                       &this->dynpool_);
       this->create_dynamic_symtab(input_objects, symtab, &dynstr,
-                                 &local_dynamic_count, &dynamic_symbols,
+                                 &local_dynamic_count,
+                                 &forced_local_dynamic_count,
+                                 &dynamic_symbols,
                                  &versions);
 
       // Create the .interp section to hold the name of the
@@ -2343,7 +3024,7 @@ Layout::finalize(const Input_objects* input_objects, Symbol_table* symtab,
       if ((!parameters->options().shared()
           || parameters->options().dynamic_linker() != NULL)
          && this->interp_segment_ == NULL)
-        this->create_interp(target);
+       this->create_interp(target);
 
       // Finish the .dynamic section to hold the dynamic data, and put
       // it in a PT_DYNAMIC segment.
@@ -2355,14 +3036,16 @@ Layout::finalize(const Input_objects* input_objects, Symbol_table* symtab,
 
       // Create the version sections.  We can't do this until the
       // dynamic string table is complete.
-      this->create_version_sections(&versions, symtab, local_dynamic_count,
+      this->create_version_sections(&versions, symtab,
+                                   (local_dynamic_count
+                                    + forced_local_dynamic_count),
                                    dynamic_symbols, dynstr);
 
       // Set the size of the _DYNAMIC symbol.  We can't do this until
       // after we call create_version_sections.
       this->set_dynamic_symbol_size(symtab);
     }
-  
+
   // Create segment headers.
   Output_segment_headers* segment_headers =
     (parameters->options().relocatable()
@@ -2381,7 +3064,7 @@ Layout::finalize(const Input_objects* input_objects, Symbol_table* symtab,
   // a linker script.
   if (this->script_options_->saw_sections_clause())
     this->place_orphan_sections_in_script();
-  
+
   Output_segment* load_seg;
   off_t off;
   unsigned int shndx;
@@ -2390,7 +3073,7 @@ Layout::finalize(const Input_objects* input_objects, Symbol_table* symtab,
   // Take a snapshot of the section layout as needed.
   if (target->may_relax())
     this->prepare_for_relaxation();
-  
+
   // Run the relaxation loop to lay out sections.
   do
     {
@@ -2402,6 +3085,18 @@ Layout::finalize(const Input_objects* input_objects, Symbol_table* symtab,
   while (target->may_relax()
         && target->relax(pass, input_objects, symtab, this, task));
 
+  // If there is a load segment that contains the file and program headers,
+  // provide a symbol __ehdr_start pointing there.
+  // A program can use this to examine itself robustly.
+  Symbol *ehdr_start = symtab->lookup("__ehdr_start");
+  if (ehdr_start != NULL && ehdr_start->is_predefined())
+    {
+      if (load_seg != NULL)
+       ehdr_start->set_output_segment(load_seg, Symbol::SEGMENT_START);
+      else
+       ehdr_start->set_undefined();
+    }
+
   // Set the file offsets of all the non-data sections we've seen so
   // far which don't have to wait for the input sections.  We need
   // this in order to finalize local symbols in non-allocated
@@ -2413,7 +3108,8 @@ Layout::finalize(const Input_objects* input_objects, Symbol_table* symtab,
   shndx = this->set_section_indexes(shndx);
 
   // Create the symbol table sections.
-  this->create_symtab_sections(input_objects, symtab, shndx, &off);
+  this->create_symtab_sections(input_objects, symtab, shndx, &off,
+                              local_dynamic_count);
   if (!parameters->doing_static_link())
     this->assign_local_dynsym_offsets(input_objects);
 
@@ -2492,6 +3188,10 @@ Layout::create_note(const char* name, int note_type,
 #else
   const int size = 32;
 #endif
+  // The NT_GNU_PROPERTY_TYPE_0 note is aligned to the pointer size.
+  const int addralign = ((note_type == elfcpp::NT_GNU_PROPERTY_TYPE_0
+                        ? parameters->target().get_size()
+                        : size) / 8);
 
   // The contents of the .note section.
   size_t namesz = strlen(name) + 1;
@@ -2549,12 +3249,13 @@ Layout::create_note(const char* name, int note_type,
     }
   Output_section* os = this->choose_output_section(NULL, section_name,
                                                   elfcpp::SHT_NOTE,
-                                                  flags, false, order, false);
+                                                  flags, false, order, false,
+                                                  false, true);
   if (os == NULL)
     return NULL;
 
   Output_section_data* posd = new Output_data_const_buffer(buffer, notehdrsz,
-                                                          size / 8,
+                                                          addralign,
                                                           "** note header");
   os->add_output_section_data(posd);
 
@@ -2563,6 +3264,58 @@ Layout::create_note(const char* name, int note_type,
   return os;
 }
 
+// Create a .note.gnu.property section to record program properties
+// accumulated from the input files.
+
+void
+Layout::create_gnu_properties_note()
+{
+  parameters->target().finalize_gnu_properties(this);
+
+  if (this->gnu_properties_.empty())
+    return;
+
+  const unsigned int size = parameters->target().get_size();
+  const bool is_big_endian = parameters->target().is_big_endian();
+
+  // Compute the total size of the properties array.
+  size_t descsz = 0;
+  for (Gnu_properties::const_iterator prop = this->gnu_properties_.begin();
+       prop != this->gnu_properties_.end();
+       ++prop)
+    {
+      descsz = align_address(descsz + 8 + prop->second.pr_datasz, size / 8);
+    }
+
+  // Create the note section.
+  size_t trailing_padding;
+  Output_section* os = this->create_note("GNU", elfcpp::NT_GNU_PROPERTY_TYPE_0,
+                                        ".note.gnu.property", descsz,
+                                        true, &trailing_padding);
+  if (os == NULL)
+    return;
+  gold_assert(trailing_padding == 0);
+
+  // Allocate and fill the properties array.
+  unsigned char* desc = new unsigned char[descsz];
+  unsigned char* p = desc;
+  for (Gnu_properties::const_iterator prop = this->gnu_properties_.begin();
+       prop != this->gnu_properties_.end();
+       ++prop)
+    {
+      size_t datasz = prop->second.pr_datasz;
+      size_t aligned_datasz = align_address(prop->second.pr_datasz, size / 8);
+      write_sized_value(prop->first, 4, p, is_big_endian);
+      write_sized_value(datasz, 4, p + 4, is_big_endian);
+      memcpy(p + 8, prop->second.pr_data, datasz);
+      if (aligned_datasz > datasz)
+       memset(p + 8 + datasz, 0, aligned_datasz - datasz);
+      p += 8 + aligned_datasz;
+    }
+  Output_section_data* posd = new Output_data_const(desc, descsz, 4);
+  os->add_output_section_data(posd);
+}
+
 // For an executable or shared library, create a note to record the
 // version of gold used to create the binary.
 
@@ -2599,18 +3352,29 @@ Layout::create_gold_note()
 // executable.  Otherwise, if at least one input file a
 // .note.GNU-stack section, and some input file has no .note.GNU-stack
 // section, we use the target default for whether the stack should be
-// executable.  Otherwise, we don't generate a stack note.  When
-// generating a object file, we create a .note.GNU-stack section with
-// the appropriate marking.  When generating an executable or shared
-// library, we create a PT_GNU_STACK segment.
+// executable.  If -z stack-size was used to set a p_memsz value for
+// PT_GNU_STACK, we generate the segment regardless.  Otherwise, we
+// don't generate a stack note.  When generating a object file, we
+// create a .note.GNU-stack section with the appropriate marking.
+// When generating an executable or shared library, we create a
+// PT_GNU_STACK segment.
 
 void
-Layout::create_executable_stack_info()
+Layout::create_stack_segment()
 {
   bool is_stack_executable;
   if (parameters->options().is_execstack_set())
-    is_stack_executable = parameters->options().is_stack_executable();
-  else if (!this->input_with_gnu_stack_note_)
+    {
+      is_stack_executable = parameters->options().is_stack_executable();
+      if (!is_stack_executable
+         && this->input_requires_executable_stack_
+         && parameters->options().warn_execstack())
+       gold_warning(_("one or more inputs require executable stack, "
+                      "but -z noexecstack was given"));
+    }
+  else if (!this->input_with_gnu_stack_note_
+          && (!parameters->options().user_set_stack_size()
+              || parameters->options().relocatable()))
     return;
   else
     {
@@ -2639,7 +3403,12 @@ Layout::create_executable_stack_info()
       int flags = elfcpp::PF_R | elfcpp::PF_W;
       if (is_stack_executable)
        flags |= elfcpp::PF_X;
-      this->make_output_segment(elfcpp::PT_GNU_STACK, flags);
+      Output_segment* seg =
+       this->make_output_segment(elfcpp::PT_GNU_STACK, flags);
+      seg->set_size(parameters->options().stack_size());
+      // BFD lets targets override this default alignment, but the only
+      // targets that do so are ones that Gold does not support so far.
+      seg->set_minimum_p_align(16);
     }
 }
 
@@ -2661,10 +3430,11 @@ Layout::create_build_id()
   std::string desc;
   if (strcmp(style, "md5") == 0)
     descsz = 128 / 8;
-  else if (strcmp(style, "sha1") == 0)
+  else if ((strcmp(style, "sha1") == 0) || (strcmp(style, "tree") == 0))
     descsz = 160 / 8;
   else if (strcmp(style, "uuid") == 0)
     {
+#ifndef __MINGW32__
       const size_t uuidsz = 128 / 8;
 
       char buffer[uuidsz];
@@ -2687,6 +3457,26 @@ Layout::create_build_id()
 
       desc.assign(buffer, uuidsz);
       descsz = uuidsz;
+#else // __MINGW32__
+      UUID uuid;
+      typedef RPC_STATUS (RPC_ENTRY *UuidCreateFn)(UUID *Uuid);
+
+      HMODULE rpc_library = LoadLibrary("rpcrt4.dll");
+      if (!rpc_library)
+       gold_error(_("--build-id=uuid failed: could not load rpcrt4.dll"));
+      else
+       {
+         UuidCreateFn uuid_create = reinterpret_cast<UuidCreateFn>(
+             GetProcAddress(rpc_library, "UuidCreate"));
+         if (!uuid_create)
+           gold_error(_("--build-id=uuid failed: could not find UuidCreate"));
+         else if (uuid_create(&uuid) != RPC_S_OK)
+           gold_error(_("__build_id=uuid failed: call UuidCreate() failed"));
+         FreeLibrary(rpc_library);
+       }
+      desc.assign(reinterpret_cast<const char *>(&uuid), sizeof(UUID));
+      descsz = sizeof(UUID);
+#endif // __MINGW32__
     }
   else if (strncmp(style, "0x", 2) == 0)
     {
@@ -2832,8 +3622,8 @@ Layout::create_incremental_info_sections(Symbol_table* symtab)
   const char* incremental_strtab_name =
     this->namepool_.add(".gnu_incremental_strtab", false, NULL);
   Output_section* incremental_strtab_os = this->make_output_section(incremental_strtab_name,
-                                                        elfcpp::SHT_STRTAB, 0,
-                                                        ORDER_INVALID, false);
+                                                       elfcpp::SHT_STRTAB, 0,
+                                                       ORDER_INVALID, false);
   Output_data_strtab* strtab_data =
       new Output_data_strtab(incr->get_stringpool());
   incremental_strtab_os->add_output_section_data(strtab_data);
@@ -2857,6 +3647,11 @@ bool
 Layout::segment_precedes(const Output_segment* seg1,
                         const Output_segment* seg2)
 {
+  // In order to produce a stable ordering if we're called with the same pointer
+  // return false.
+  if (seg1 == seg2)
+    return false;
+
   elfcpp::Elf_Word type1 = seg1->type();
   elfcpp::Elf_Word type2 = seg2->type();
 
@@ -2912,12 +3707,19 @@ Layout::segment_precedes(const Output_segment* seg1,
 
   // The order of non-PT_LOAD segments is unimportant.  We simply sort
   // by the numeric segment type and flags values.  There should not
-  // be more than one segment with the same type and flags.
+  // be more than one segment with the same type and flags, except
+  // when a linker script specifies such.
   if (type1 != elfcpp::PT_LOAD)
     {
       if (type1 != type2)
        return type1 < type2;
-      gold_assert(flags1 != flags2);
+      uint64_t align1 = seg1->align();
+      uint64_t align2 = seg2->align();
+      // Place segments with larger alignments first.
+      if (align1 != align2)
+       return align1 > align2;
+      gold_assert(flags1 != flags2
+                 || this->script_options_->saw_phdrs_clause());
       return flags1 < flags2;
     }
 
@@ -2978,9 +3780,12 @@ Layout::segment_precedes(const Output_segment* seg1,
 
   // We shouldn't get here--we shouldn't create segments which we
   // can't distinguish.  Unless of course we are using a weird linker
-  // script or overlapping --section-start options.
+  // script or overlapping --section-start options.  We could also get
+  // here if plugins want unique segments for subsets of sections.
   gold_assert(this->script_options_->saw_phdrs_clause()
-             || parameters->options().any_section_start());
+             || parameters->options().any_section_start()
+             || this->is_unique_segment_for_sections_specified()
+             || parameters->options().text_unlikely_segment());
   return false;
 }
 
@@ -2997,8 +3802,22 @@ align_file_offset(off_t off, uint64_t addr, uint64_t abi_pagesize)
   return aligned_off;
 }
 
+// On targets where the text segment contains only executable code,
+// a non-executable segment is never the text segment.
+
+static inline bool
+is_text_segment(const Target* target, const Output_segment* seg)
+{
+  elfcpp::Elf_Xword flags = seg->flags();
+  if ((flags & elfcpp::PF_W) != 0)
+    return false;
+  if ((flags & elfcpp::PF_X) == 0)
+    return !target->isolate_execinstr();
+  return true;
+}
+
 // Set the file offsets of all the segments, and all the sections they
-// contain.  They have all been created.  LOAD_SEG must be be laid out
+// contain.  They have all been created.  LOAD_SEG must be laid out
 // first.  Return the offset of the data to follow.
 
 off_t
@@ -3013,13 +3832,15 @@ Layout::set_segment_offsets(const Target* target, Output_segment* load_seg,
 
   // Find the PT_LOAD segments, and set their addresses and offsets
   // and their section's addresses and offsets.
-  uint64_t addr;
+  uint64_t start_addr;
   if (parameters->options().user_set_Ttext())
-    addr = parameters->options().Ttext();
+    start_addr = parameters->options().Ttext();
   else if (parameters->options().output_is_position_independent())
-    addr = 0;
+    start_addr = 0;
   else
-    addr = target->default_text_segment_address();
+    start_addr = target->default_text_segment_address();
+
+  uint64_t addr = start_addr;
   off_t off = 0;
 
   // If LOAD_SEG is NULL, then the file header and segment headers
@@ -3044,15 +3865,39 @@ Layout::set_segment_offsets(const Target* target, Output_segment* load_seg,
   const bool check_sections = parameters->options().check_sections();
   Output_segment* last_load_segment = NULL;
 
+  unsigned int shndx_begin = *pshndx;
+  unsigned int shndx_load_seg = *pshndx;
+
   for (Segment_list::iterator p = this->segment_list_.begin();
        p != this->segment_list_.end();
        ++p)
     {
       if ((*p)->type() == elfcpp::PT_LOAD)
        {
-         if (load_seg != NULL && load_seg != *p)
-           gold_unreachable();
-         load_seg = NULL;
+         if (target->isolate_execinstr())
+           {
+             // When we hit the segment that should contain the
+             // file headers, reset the file offset so we place
+             // it and subsequent segments appropriately.
+             // We'll fix up the preceding segments below.
+             if (load_seg == *p)
+               {
+                 if (off == 0)
+                   load_seg = NULL;
+                 else
+                   {
+                     off = 0;
+                     shndx_load_seg = *pshndx;
+                   }
+               }
+           }
+         else
+           {
+             // Verify that the file headers fall into the first segment.
+             if (load_seg != NULL && load_seg != *p)
+               gold_unreachable();
+             load_seg = NULL;
+           }
 
          bool are_addresses_set = (*p)->are_addresses_set();
          if (are_addresses_set)
@@ -3062,8 +3907,15 @@ Layout::set_segment_offsets(const Target* target, Output_segment* load_seg,
              addr = (*p)->paddr();
            }
          else if (parameters->options().user_set_Ttext()
-                  && ((*p)->flags() & elfcpp::PF_W) == 0)
+                  && (parameters->options().omagic()
+                      || is_text_segment(target, *p)))
+           {
+             are_addresses_set = true;
+           }
+         else if (parameters->options().user_set_Trodata_segment()
+                  && ((*p)->flags() & (elfcpp::PF_W | elfcpp::PF_X)) == 0)
            {
+             addr = parameters->options().Trodata_segment();
              are_addresses_set = true;
            }
          else if (parameters->options().user_set_Tdata()
@@ -3091,7 +3943,7 @@ Layout::set_segment_offsets(const Target* target, Output_segment* load_seg,
 
          if (!parameters->options().nmagic()
              && !parameters->options().omagic())
-           (*p)->set_minimum_p_align(common_pagesize);
+           (*p)->set_minimum_p_align(abi_pagesize);
 
          if (!are_addresses_set)
            {
@@ -3101,19 +3953,51 @@ Layout::set_segment_offsets(const Target* target, Output_segment* load_seg,
              // put them on different pages in memory. We will revisit this
              // decision once we know the size of the segment.
 
-             addr = align_address(addr, (*p)->maximum_alignment());
+             uint64_t max_align = (*p)->maximum_alignment();
+             if (max_align > abi_pagesize)
+               addr = align_address(addr, max_align);
              aligned_addr = addr;
 
-             if ((addr & (abi_pagesize - 1)) != 0)
-                addr = addr + abi_pagesize;
+             if (load_seg == *p)
+               {
+                 // This is the segment that will contain the file
+                 // headers, so its offset will have to be exactly zero.
+                 gold_assert(orig_off == 0);
+
+                 // If the target wants a fixed minimum distance from the
+                 // text segment to the read-only segment, move up now.
+                 uint64_t min_addr =
+                   start_addr + (parameters->options().user_set_rosegment_gap()
+                                 ? parameters->options().rosegment_gap()
+                                 : target->rosegment_gap());
+                 if (addr < min_addr)
+                   addr = min_addr;
+
+                 // But this is not the first segment!  To make its
+                 // address congruent with its offset, that address better
+                 // be aligned to the ABI-mandated page size.
+                 addr = align_address(addr, abi_pagesize);
+                 aligned_addr = addr;
+               }
+             else
+               {
+                 if ((addr & (abi_pagesize - 1)) != 0)
+                   addr = addr + abi_pagesize;
 
-             off = orig_off + ((addr - orig_addr) & (abi_pagesize - 1));
+                 off = orig_off + ((addr - orig_addr) & (abi_pagesize - 1));
+               }
            }
 
          if (!parameters->options().nmagic()
              && !parameters->options().omagic())
-           off = align_file_offset(off, addr, abi_pagesize);
-         else if (load_seg == NULL)
+           {
+             // Here we are also taking care of the case when
+             // the maximum segment alignment is larger than the page size.
+             off = align_file_offset(off, addr,
+                                     std::max(abi_pagesize,
+                                              (*p)->maximum_alignment()));
+           }
+         else
            {
              // This is -N or -n with a section script which prevents
              // us from using a load segment.  We need to ensure that
@@ -3129,10 +4013,11 @@ Layout::set_segment_offsets(const Target* target, Output_segment* load_seg,
 
          unsigned int shndx_hold = *pshndx;
          bool has_relro = false;
-         uint64_t new_addr = (*p)->set_section_addresses(this, false, addr,
+         uint64_t new_addr = (*p)->set_section_addresses(target, this,
+                                                         false, addr,
                                                          &increase_relro,
                                                          &has_relro,
-                                                          &off, pshndx);
+                                                         &off, pshndx);
 
          // Now that we know the size of this segment, we may be able
          // to save a page in memory, at the cost of wasting some
@@ -3160,6 +4045,8 @@ Layout::set_segment_offsets(const Target* target, Output_segment* load_seg,
                  *pshndx = shndx_hold;
                  addr = align_address(aligned_addr, common_pagesize);
                  addr = align_address(addr, (*p)->maximum_alignment());
+                 if ((addr & (abi_pagesize - 1)) != 0)
+                   addr = addr + abi_pagesize;
                  off = orig_off + ((addr - orig_addr) & (abi_pagesize - 1));
                  off = align_file_offset(off, addr, abi_pagesize);
 
@@ -3168,10 +4055,11 @@ Layout::set_segment_offsets(const Target* target, Output_segment* load_seg,
                    increase_relro = 0;
                  has_relro = false;
 
-                 new_addr = (*p)->set_section_addresses(this, true, addr,
+                 new_addr = (*p)->set_section_addresses(target, this,
+                                                        true, addr,
                                                         &increase_relro,
                                                         &has_relro,
-                                                         &off, pshndx);
+                                                        &off, pshndx);
                }
            }
 
@@ -3198,13 +4086,49 @@ Layout::set_segment_offsets(const Target* target, Output_segment* load_seg,
        }
     }
 
+  if (load_seg != NULL && target->isolate_execinstr())
+    {
+      // Process the early segments again, setting their file offsets
+      // so they land after the segments starting at LOAD_SEG.
+      off = align_file_offset(off, 0, target->abi_pagesize());
+
+      this->reset_relax_output();
+
+      for (Segment_list::iterator p = this->segment_list_.begin();
+          *p != load_seg;
+          ++p)
+       {
+         if ((*p)->type() == elfcpp::PT_LOAD)
+           {
+             // We repeat the whole job of assigning addresses and
+             // offsets, but we really only want to change the offsets and
+             // must ensure that the addresses all come out the same as
+             // they did the first time through.
+             bool has_relro = false;
+             const uint64_t old_addr = (*p)->vaddr();
+             const uint64_t old_end = old_addr + (*p)->memsz();
+             uint64_t new_addr = (*p)->set_section_addresses(target, this,
+                                                             true, old_addr,
+                                                             &increase_relro,
+                                                             &has_relro,
+                                                             &off,
+                                                             &shndx_begin);
+             gold_assert(new_addr == old_end);
+           }
+       }
+
+      gold_assert(shndx_begin == shndx_load_seg);
+    }
+
   // Handle the non-PT_LOAD segments, setting their offsets from their
   // section's offsets.
   for (Segment_list::iterator p = this->segment_list_.begin();
        p != this->segment_list_.end();
        ++p)
     {
-      if ((*p)->type() != elfcpp::PT_LOAD)
+      // PT_GNU_STACK was set up correctly when it was created.
+      if ((*p)->type() != elfcpp::PT_LOAD
+         && (*p)->type() != elfcpp::PT_GNU_STACK)
        (*p)->set_offset((*p)->type() == elfcpp::PT_GNU_RELRO
                         ? increase_relro
                         : 0);
@@ -3247,7 +4171,8 @@ Layout::set_relocatable_section_offsets(Output_data* file_header,
        (*p)->set_address(0);
       (*p)->set_file_offset(off);
       (*p)->finalize_data_size();
-      off += (*p)->data_size();
+      if ((*p)->type() != elfcpp::SHT_NOBITS)
+       off += (*p)->data_size();
 
       (*p)->set_out_shndx(*pshndx);
       ++*pshndx;
@@ -3285,16 +4210,16 @@ Layout::set_section_offsets(off_t off, Layout::Section_offset_pass pass)
        }
 
       if (pass == BEFORE_INPUT_SECTIONS_PASS
-          && (*p)->after_input_sections())
-        continue;
+         && (*p)->after_input_sections())
+       continue;
       else if (pass == POSTPROCESSING_SECTIONS_PASS
-               && (!(*p)->after_input_sections()
-                   || (*p)->type() == elfcpp::SHT_STRTAB))
-        continue;
+              && (!(*p)->after_input_sections()
+                  || (*p)->type() == elfcpp::SHT_STRTAB))
+       continue;
       else if (pass == STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
-               && (!(*p)->after_input_sections()
-                   || (*p)->type() != elfcpp::SHT_STRTAB))
-        continue;
+              && (!(*p)->after_input_sections()
+                  || (*p)->type() != elfcpp::SHT_STRTAB))
+       continue;
 
       if (!parameters->incremental_update())
        {
@@ -3311,7 +4236,7 @@ Layout::set_section_offsets(off_t off, Layout::Section_offset_pass pass)
          if (off == -1)
            {
              if (is_debugging_enabled(DEBUG_INCREMENTAL))
-               this->free_list_.dump();
+               this->free_list_.dump();
              gold_assert((*p)->output_section() != NULL);
              gold_fallback(_("out of patch space for section %s; "
                              "relink with --incremental-full"),
@@ -3336,7 +4261,7 @@ Layout::set_section_offsets(off_t off, Layout::Section_offset_pass pass)
 
       off += (*p)->data_size();
       if (off > maxoff)
-        maxoff = off;
+       maxoff = off;
 
       // At this point the name must be set.
       if (pass != STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS)
@@ -3439,7 +4364,8 @@ void
 Layout::create_symtab_sections(const Input_objects* input_objects,
                               Symbol_table* symtab,
                               unsigned int shnum,
-                              off_t* poff)
+                              off_t* poff,
+                              unsigned int local_dynamic_count)
 {
   int symsize;
   unsigned int align;
@@ -3484,7 +4410,7 @@ Layout::create_symtab_sections(const Input_objects* input_objects,
        ++p)
     {
       unsigned int index = (*p)->finalize_local_symbols(local_symbol_index,
-                                                        off, symtab);
+                                                       off, symtab);
       off += (index - local_symbol_index) * symsize;
       local_symbol_index = index;
     }
@@ -3493,18 +4419,15 @@ Layout::create_symtab_sections(const Input_objects* input_objects,
   gold_assert(static_cast<off_t>(local_symcount * symsize) == off);
 
   off_t dynoff;
-  size_t dyn_global_index;
   size_t dyncount;
   if (this->dynsym_section_ == NULL)
     {
       dynoff = 0;
-      dyn_global_index = 0;
       dyncount = 0;
     }
   else
     {
-      dyn_global_index = this->dynsym_section_->info();
-      off_t locsize = dyn_global_index * this->dynsym_section_->entsize();
+      off_t locsize = local_dynamic_count * this->dynsym_section_->entsize();
       dynoff = this->dynsym_section_->offset() + locsize;
       dyncount = (this->dynsym_section_->data_size() - locsize) / symsize;
       gold_assert(static_cast<off_t>(dyncount * symsize)
@@ -3512,7 +4435,7 @@ Layout::create_symtab_sections(const Input_objects* input_objects,
     }
 
   off_t global_off = off;
-  off = symtab->finalize(off, dynoff, dyn_global_index, dyncount,
+  off = symtab->finalize(off, dynoff, local_dynamic_count, dyncount,
                         &this->sympool_, &local_symcount);
 
   if (!parameters->options().strip_all())
@@ -3578,7 +4501,7 @@ Layout::create_symtab_sections(const Input_objects* input_objects,
       else
        {
          symtab_off = this->allocate(off, align, *poff);
-          if (off == -1)
+         if (off == -1)
            gold_fallback(_("out of patch space for symbol table; "
                            "relink with --incremental-full"));
          gold_debug(DEBUG_INCREMENTAL,
@@ -3678,12 +4601,18 @@ Layout::allocated_output_section_count() const
 }
 
 // Create the dynamic symbol table.
+// *PLOCAL_DYNAMIC_COUNT will be set to the number of local symbols
+// from input objects, and *PFORCED_LOCAL_DYNAMIC_COUNT will be set
+// to the number of global symbols that have been forced local.
+// We need to remember the former because the forced-local symbols are
+// written along with the global symbols in Symtab::write_globals().
 
 void
 Layout::create_dynamic_symtab(const Input_objects* input_objects,
-                              Symbol_table* symtab,
+                             Symbol_table* symtab,
                              Output_section** pdynstr,
                              unsigned int* plocal_dynamic_count,
+                             unsigned int* pforced_local_dynamic_count,
                              std::vector<Symbol*>* pdynamic_symbols,
                              Versions* pversions)
 {
@@ -3718,10 +4647,14 @@ Layout::create_dynamic_symtab(const Input_objects* input_objects,
     }
 
   unsigned int local_symcount = index;
-  *plocal_dynamic_count = local_symcount;
+  unsigned int forced_local_count = 0;
 
-  index = symtab->set_dynsym_indexes(index, pdynamic_symbols,
-                                    &this->dynpool_, pversions);
+  index = symtab->set_dynsym_indexes(index, &forced_local_count,
+                                    pdynamic_symbols, &this->dynpool_,
+                                    pversions);
+
+  *plocal_dynamic_count = local_symcount;
+  *pforced_local_dynamic_count = forced_local_count;
 
   int symsize;
   unsigned int align;
@@ -3746,7 +4679,7 @@ Layout::create_dynamic_symtab(const Input_objects* input_objects,
                                                       elfcpp::SHF_ALLOC,
                                                       false,
                                                       ORDER_DYNAMIC_LINKER,
-                                                      false);
+                                                      false, false, false);
 
   // Check for NULL as a linker script may discard .dynsym.
   if (dynsym != NULL)
@@ -3756,7 +4689,7 @@ Layout::create_dynamic_symtab(const Input_objects* input_objects,
                                                               "** dynsym");
       dynsym->add_output_section_data(odata);
 
-      dynsym->set_info(local_symcount);
+      dynsym->set_info(local_symcount + forced_local_count);
       dynsym->set_entsize(symsize);
       dynsym->set_addralign(align);
 
@@ -3783,7 +4716,8 @@ Layout::create_dynamic_symtab(const Input_objects* input_objects,
        this->choose_output_section(NULL, ".dynsym_shndx",
                                    elfcpp::SHT_SYMTAB_SHNDX,
                                    elfcpp::SHF_ALLOC,
-                                   false, ORDER_DYNAMIC_LINKER, false);
+                                   false, ORDER_DYNAMIC_LINKER, false, false,
+                                   false);
 
       if (dynsym_xindex != NULL)
        {
@@ -3811,8 +4745,8 @@ Layout::create_dynamic_symtab(const Input_objects* input_objects,
                                                       elfcpp::SHF_ALLOC,
                                                       false,
                                                       ORDER_DYNAMIC_LINKER,
-                                                      false);
-
+                                                      false, false, false);
+  *pdynstr = dynstr;
   if (dynstr != NULL)
     {
       Output_section_data* strdata = new Output_data_strtab(&this->dynpool_);
@@ -3828,24 +4762,26 @@ Layout::create_dynamic_symtab(const Input_objects* input_objects,
          odyn->add_section_address(elfcpp::DT_STRTAB, dynstr);
          odyn->add_section_size(elfcpp::DT_STRSZ, dynstr);
        }
-
-      *pdynstr = dynstr;
     }
 
-  // Create the hash tables.
+  // Create the hash tables.  The Gnu-style hash table must be
+  // built first, because it changes the order of the symbols
+  // in the dynamic symbol table.
 
-  if (strcmp(parameters->options().hash_style(), "sysv") == 0
+  if (strcmp(parameters->options().hash_style(), "gnu") == 0
       || strcmp(parameters->options().hash_style(), "both") == 0)
     {
       unsigned char* phash;
       unsigned int hashlen;
-      Dynobj::create_elf_hash_table(*pdynamic_symbols, local_symcount,
+      Dynobj::create_gnu_hash_table(*pdynamic_symbols,
+                                   local_symcount + forced_local_count,
                                    &phash, &hashlen);
 
       Output_section* hashsec =
-       this->choose_output_section(NULL, ".hash", elfcpp::SHT_HASH,
+       this->choose_output_section(NULL, ".gnu.hash", elfcpp::SHT_GNU_HASH,
                                    elfcpp::SHF_ALLOC, false,
-                                   ORDER_DYNAMIC_LINKER, false);
+                                   ORDER_DYNAMIC_LINKER, false, false,
+                                   false);
 
       Output_section_data* hashdata = new Output_data_const_buffer(phash,
                                                                   hashlen,
@@ -3858,25 +4794,32 @@ Layout::create_dynamic_symtab(const Input_objects* input_objects,
        {
          if (dynsym != NULL)
            hashsec->set_link_section(dynsym);
-         hashsec->set_entsize(4);
-       }
 
-      if (odyn != NULL)
-       odyn->add_section_address(elfcpp::DT_HASH, hashsec);
+         // For a 64-bit target, the entries in .gnu.hash do not have
+         // a uniform size, so we only set the entry size for a
+         // 32-bit target.
+         if (parameters->target().get_size() == 32)
+           hashsec->set_entsize(4);
+
+         if (odyn != NULL)
+           odyn->add_section_address(elfcpp::DT_GNU_HASH, hashsec);
+       }
     }
 
-  if (strcmp(parameters->options().hash_style(), "gnu") == 0
+  if (strcmp(parameters->options().hash_style(), "sysv") == 0
       || strcmp(parameters->options().hash_style(), "both") == 0)
     {
       unsigned char* phash;
       unsigned int hashlen;
-      Dynobj::create_gnu_hash_table(*pdynamic_symbols, local_symcount,
+      Dynobj::create_elf_hash_table(*pdynamic_symbols,
+                                   local_symcount + forced_local_count,
                                    &phash, &hashlen);
 
       Output_section* hashsec =
-       this->choose_output_section(NULL, ".gnu.hash", elfcpp::SHT_GNU_HASH,
+       this->choose_output_section(NULL, ".hash", elfcpp::SHT_HASH,
                                    elfcpp::SHF_ALLOC, false,
-                                   ORDER_DYNAMIC_LINKER, false);
+                                   ORDER_DYNAMIC_LINKER, false, false,
+                                   false);
 
       Output_section_data* hashdata = new Output_data_const_buffer(phash,
                                                                   hashlen,
@@ -3889,16 +4832,11 @@ Layout::create_dynamic_symtab(const Input_objects* input_objects,
        {
          if (dynsym != NULL)
            hashsec->set_link_section(dynsym);
-
-         // For a 64-bit target, the entries in .gnu.hash do not have
-         // a uniform size, so we only set the entry size for a
-         // 32-bit target.
-         if (parameters->target().get_size() == 32)
-           hashsec->set_entsize(4);
-
-         if (odyn != NULL)
-           odyn->add_section_address(elfcpp::DT_GNU_HASH, hashsec);
+         hashsec->set_entsize(parameters->target().hash_entry_size() / 8);
        }
+
+      if (odyn != NULL)
+       odyn->add_section_address(elfcpp::DT_HASH, hashsec);
     }
 }
 
@@ -3988,7 +4926,7 @@ Layout::sized_create_version_sections(
                                                     elfcpp::SHF_ALLOC,
                                                     false,
                                                     ORDER_DYNAMIC_LINKER,
-                                                    false);
+                                                    false, false, false);
 
   // Check for NULL since a linker script may discard this section.
   if (vsec != NULL)
@@ -4019,7 +4957,8 @@ Layout::sized_create_version_sections(
       vdsec = this->choose_output_section(NULL, ".gnu.version_d",
                                          elfcpp::SHT_GNU_verdef,
                                          elfcpp::SHF_ALLOC,
-                                         false, ORDER_DYNAMIC_LINKER, false);
+                                         false, ORDER_DYNAMIC_LINKER, false,
+                                         false, false);
 
       if (vdsec != NULL)
        {
@@ -4051,7 +4990,8 @@ Layout::sized_create_version_sections(
       vnsec = this->choose_output_section(NULL, ".gnu.version_r",
                                          elfcpp::SHT_GNU_verneed,
                                          elfcpp::SHF_ALLOC,
-                                         false, ORDER_DYNAMIC_LINKER, false);
+                                         false, ORDER_DYNAMIC_LINKER, false,
+                                         false, false);
 
       if (vnsec != NULL)
        {
@@ -4100,7 +5040,7 @@ Layout::create_interp(const Target* target)
                                                     elfcpp::SHT_PROGBITS,
                                                     elfcpp::SHF_ALLOC,
                                                     false, ORDER_INTERP,
-                                                    false);
+                                                    false, false, false);
   if (osec != NULL)
     osec->add_output_section_data(odata);
 }
@@ -4145,19 +5085,26 @@ Layout::add_target_dynamic_tags(bool use_rel, const Output_data* plt_got,
                         use_rel ? elfcpp::DT_REL : elfcpp::DT_RELA);
     }
 
-  if (dyn_rel != NULL && dyn_rel->output_section() != NULL)
+  if ((dyn_rel != NULL && dyn_rel->output_section() != NULL)
+      || (dynrel_includes_plt
+         && plt_rel != NULL
+         && plt_rel->output_section() != NULL))
     {
+      bool have_dyn_rel = dyn_rel != NULL && dyn_rel->output_section() != NULL;
+      bool have_plt_rel = plt_rel != NULL && plt_rel->output_section() != NULL;
       odyn->add_section_address(use_rel ? elfcpp::DT_REL : elfcpp::DT_RELA,
-                               dyn_rel->output_section());
-      if (plt_rel != NULL
-         && plt_rel->output_section() != NULL
-         && dynrel_includes_plt)
-       odyn->add_section_size(use_rel ? elfcpp::DT_RELSZ : elfcpp::DT_RELASZ,
+                               (have_dyn_rel
+                                ? dyn_rel->output_section()
+                                : plt_rel->output_section()));
+      elfcpp::DT size_tag = use_rel ? elfcpp::DT_RELSZ : elfcpp::DT_RELASZ;
+      if (have_dyn_rel && have_plt_rel && dynrel_includes_plt)
+       odyn->add_section_size(size_tag,
                               dyn_rel->output_section(),
                               plt_rel->output_section());
+      else if (have_dyn_rel)
+       odyn->add_section_size(size_tag, dyn_rel->output_section());
       else
-       odyn->add_section_size(use_rel ? elfcpp::DT_RELSZ : elfcpp::DT_RELASZ,
-                              dyn_rel->output_section());
+       odyn->add_section_size(size_tag, plt_rel->output_section());
       const int size = parameters->target().get_size();
       elfcpp::DT rel_tag;
       int rel_size;
@@ -4183,7 +5130,7 @@ Layout::add_target_dynamic_tags(bool use_rel, const Output_data* plt_got,
        }
       odyn->add_constant(rel_tag, rel_size);
 
-      if (parameters->options().combreloc())
+      if (parameters->options().combreloc() && have_dyn_rel)
        {
          size_t c = dyn_rel->relative_reloc_count();
          if (c > 0)
@@ -4202,6 +5149,15 @@ Layout::add_target_dynamic_tags(bool use_rel, const Output_data* plt_got,
     }
 }
 
+void
+Layout::add_target_specific_dynamic_tag(elfcpp::DT tag, unsigned int val)
+{
+  Output_data_dynamic* odyn = this->dynamic_data_;
+  if (odyn == NULL)
+    return;
+  odyn->add_constant(tag, val);
+}
+
 // Finish the .dynamic section and PT_DYNAMIC segment.
 
 void
@@ -4260,48 +5216,49 @@ Layout::finish_dynamic_section(const Input_objects* input_objects,
       {
       case elfcpp::SHT_FINI_ARRAY:
        odyn->add_section_address(elfcpp::DT_FINI_ARRAY, *p);
-       odyn->add_section_size(elfcpp::DT_FINI_ARRAYSZ, *p); 
+       odyn->add_section_size(elfcpp::DT_FINI_ARRAYSZ, *p);
        break;
       case elfcpp::SHT_INIT_ARRAY:
        odyn->add_section_address(elfcpp::DT_INIT_ARRAY, *p);
-       odyn->add_section_size(elfcpp::DT_INIT_ARRAYSZ, *p); 
+       odyn->add_section_size(elfcpp::DT_INIT_ARRAYSZ, *p);
        break;
       case elfcpp::SHT_PREINIT_ARRAY:
        odyn->add_section_address(elfcpp::DT_PREINIT_ARRAY, *p);
-       odyn->add_section_size(elfcpp::DT_PREINIT_ARRAYSZ, *p); 
+       odyn->add_section_size(elfcpp::DT_PREINIT_ARRAYSZ, *p);
        break;
       default:
        break;
       }
-  
+
   // Add a DT_RPATH entry if needed.
   const General_options::Dir_list& rpath(parameters->options().rpath());
   if (!rpath.empty())
     {
       std::string rpath_val;
       for (General_options::Dir_list::const_iterator p = rpath.begin();
-           p != rpath.end();
-           ++p)
-        {
-          if (rpath_val.empty())
-            rpath_val = p->name();
-          else
-            {
-              // Eliminate duplicates.
-              General_options::Dir_list::const_iterator q;
-              for (q = rpath.begin(); q != p; ++q)
+          p != rpath.end();
+          ++p)
+       {
+         if (rpath_val.empty())
+           rpath_val = p->name();
+         else
+           {
+             // Eliminate duplicates.
+             General_options::Dir_list::const_iterator q;
+             for (q = rpath.begin(); q != p; ++q)
                if (q->name() == p->name())
-                  break;
-              if (q == p)
-                {
-                  rpath_val += ':';
-                  rpath_val += p->name();
-                }
-            }
-        }
-
-      odyn->add_string(elfcpp::DT_RPATH, rpath_val);
-      if (parameters->options().enable_new_dtags())
+                 break;
+             if (q == p)
+               {
+                 rpath_val += ':';
+                 rpath_val += p->name();
+               }
+           }
+       }
+
+      if (!parameters->options().enable_new_dtags())
+       odyn->add_string(elfcpp::DT_RPATH, rpath_val);
+      else
        odyn->add_string(elfcpp::DT_RUNPATH, rpath_val);
     }
 
@@ -4310,17 +5267,17 @@ Layout::finish_dynamic_section(const Input_objects* input_objects,
   if (!this->script_options_->saw_sections_clause())
     {
       for (Segment_list::const_iterator p = this->segment_list_.begin();
-           p != this->segment_list_.end();
-           ++p)
-        {
-          if ((*p)->type() == elfcpp::PT_LOAD
+          p != this->segment_list_.end();
+          ++p)
+       {
+         if ((*p)->type() == elfcpp::PT_LOAD
              && ((*p)->flags() & elfcpp::PF_W) == 0
-              && (*p)->has_dynamic_reloc())
-            {
-              have_textrel = true;
-              break;
-            }
-        }
+             && (*p)->has_dynamic_reloc())
+           {
+             have_textrel = true;
+             break;
+           }
+       }
     }
   else
     {
@@ -4329,17 +5286,17 @@ Layout::finish_dynamic_section(const Input_objects* input_objects,
       // relocations.  If those sections wind up in writable segments,
       // then we have created an unnecessary DT_TEXTREL entry.
       for (Section_list::const_iterator p = this->section_list_.begin();
-           p != this->section_list_.end();
-           ++p)
-        {
-          if (((*p)->flags() & elfcpp::SHF_ALLOC) != 0
-              && ((*p)->flags() & elfcpp::SHF_WRITE) == 0
-              && (*p)->has_dynamic_reloc())
-            {
-              have_textrel = true;
-              break;
-            }
-        }
+          p != this->section_list_.end();
+          ++p)
+       {
+         if (((*p)->flags() & elfcpp::SHF_ALLOC) != 0
+             && ((*p)->flags() & elfcpp::SHF_WRITE) == 0
+             && (*p)->has_dynamic_reloc())
+           {
+             have_textrel = true;
+             break;
+           }
+       }
     }
 
   if (parameters->options().filter() != NULL)
@@ -4371,7 +5328,8 @@ Layout::finish_dynamic_section(const Input_objects* input_objects,
     flags |= elfcpp::DF_STATIC_TLS;
   if (parameters->options().origin())
     flags |= elfcpp::DF_ORIGIN;
-  if (parameters->options().Bsymbolic())
+  if (parameters->options().Bsymbolic()
+      && !parameters->options().have_dynamic_list())
     {
       flags |= elfcpp::DF_SYMBOLIC;
       // Add DT_SYMBOLIC for compatibility with older loaders.
@@ -4383,6 +5341,8 @@ Layout::finish_dynamic_section(const Input_objects* input_objects,
     odyn->add_constant(elfcpp::DT_FLAGS, flags);
 
   flags = 0;
+  if (parameters->options().global())
+    flags |= elfcpp::DF_1_GLOBAL;
   if (parameters->options().initfirst())
     flags |= elfcpp::DF_1_INITFIRST;
   if (parameters->options().interpose())
@@ -4407,8 +5367,16 @@ Layout::finish_dynamic_section(const Input_objects* input_objects,
     flags |= elfcpp::DF_1_NOW;
   if (parameters->options().Bgroup())
     flags |= elfcpp::DF_1_GROUP;
+  if (parameters->options().pie())
+    flags |= elfcpp::DF_1_PIE;
   if (flags != 0)
     odyn->add_constant(elfcpp::DT_FLAGS_1, flags);
+
+  flags = 0;
+  if (parameters->options().unique())
+    flags |= elfcpp::DF_GNU_1_UNIQUE;
+  if (flags != 0)
+    odyn->add_constant(elfcpp::DT_GNU_FLAGS_1, flags);
 }
 
 // Set the size of the _DYNAMIC symbol table to be the size of the
@@ -4439,12 +5407,15 @@ Layout::set_dynamic_symbol_size(const Symbol_table* symtab)
 // based on the GNU linker default ELF linker script.
 
 #define MAPPING_INIT(f, t) { f, sizeof(f) - 1, t, sizeof(t) - 1 }
+#define MAPPING_INIT_EXACT(f, t) { f, 0, t, sizeof(t) - 1 }
 const Layout::Section_name_mapping Layout::section_name_mapping[] =
 {
   MAPPING_INIT(".text.", ".text"),
   MAPPING_INIT(".rodata.", ".rodata"),
-  MAPPING_INIT(".data.rel.ro.local", ".data.rel.ro.local"),
-  MAPPING_INIT(".data.rel.ro", ".data.rel.ro"),
+  MAPPING_INIT(".data.rel.ro.local.", ".data.rel.ro.local"),
+  MAPPING_INIT_EXACT(".data.rel.ro.local", ".data.rel.ro.local"),
+  MAPPING_INIT(".data.rel.ro.", ".data.rel.ro"),
+  MAPPING_INIT_EXACT(".data.rel.ro", ".data.rel.ro"),
   MAPPING_INIT(".data.", ".data"),
   MAPPING_INIT(".bss.", ".bss"),
   MAPPING_INIT(".tdata.", ".tdata"),
@@ -4481,13 +5452,62 @@ const Layout::Section_name_mapping Layout::section_name_mapping[] =
   MAPPING_INIT(".gnu.linkonce.armextab.", ".ARM.extab"),
   MAPPING_INIT(".ARM.exidx", ".ARM.exidx"),
   MAPPING_INIT(".gnu.linkonce.armexidx.", ".ARM.exidx"),
+  MAPPING_INIT(".gnu.build.attributes.", ".gnu.build.attributes"),
+};
+
+// Mapping for ".text" section prefixes with -z,keep-text-section-prefix.
+const Layout::Section_name_mapping Layout::text_section_name_mapping[] =
+{
+  MAPPING_INIT(".text.hot.", ".text.hot"),
+  MAPPING_INIT_EXACT(".text.hot", ".text.hot"),
+  MAPPING_INIT(".text.unlikely.", ".text.unlikely"),
+  MAPPING_INIT_EXACT(".text.unlikely", ".text.unlikely"),
+  MAPPING_INIT(".text.startup.", ".text.startup"),
+  MAPPING_INIT_EXACT(".text.startup", ".text.startup"),
+  MAPPING_INIT(".text.exit.", ".text.exit"),
+  MAPPING_INIT_EXACT(".text.exit", ".text.exit"),
+  MAPPING_INIT(".text.", ".text"),
 };
 #undef MAPPING_INIT
+#undef MAPPING_INIT_EXACT
 
 const int Layout::section_name_mapping_count =
   (sizeof(Layout::section_name_mapping)
    / sizeof(Layout::section_name_mapping[0]));
 
+const int Layout::text_section_name_mapping_count =
+  (sizeof(Layout::text_section_name_mapping)
+   / sizeof(Layout::text_section_name_mapping[0]));
+
+// Find section name NAME in PSNM and return the mapped name if found
+// with the length set in PLEN.
+const char *
+Layout::match_section_name(const Layout::Section_name_mapping* psnm,
+                          const int count,
+                          const char* name, size_t* plen)
+{
+  for (int i = 0; i < count; ++i, ++psnm)
+    {
+      if (psnm->fromlen > 0)
+       {
+         if (strncmp(name, psnm->from, psnm->fromlen) == 0)
+           {
+             *plen = psnm->tolen;
+             return psnm->to;
+           }
+       }
+      else
+       {
+         if (strcmp(name, psnm->from) == 0)
+           {
+             *plen = psnm->tolen;
+             return psnm->to;
+           }
+       }
+    }
+  return NULL;
+}
+
 // Choose the output section name to use given an input section name.
 // Set *PLEN to the length of the name.  *PLEN is initialized to the
 // length of NAME.
@@ -4531,16 +5551,21 @@ Layout::output_section_name(const Relobj* relobj, const char* name,
   // not found in the table, we simply use it as the output section
   // name.
 
-  const Section_name_mapping* psnm = section_name_mapping;
-  for (int i = 0; i < section_name_mapping_count; ++i, ++psnm)
+  if (parameters->options().keep_text_section_prefix()
+      && is_prefix_of(".text", name))
     {
-      if (strncmp(name, psnm->from, psnm->fromlen) == 0)
-       {
-         *plen = psnm->tolen;
-         return psnm->to;
-       }
+      const char* match = match_section_name(text_section_name_mapping,
+                                            text_section_name_mapping_count,
+                                            name, plen);
+      if (match != NULL)
+       return match;
     }
 
+  const char* match = match_section_name(section_name_mapping,
+                                        section_name_mapping_count, name, plen);
+  if (match != NULL)
+    return match;
+
   // As an additional complication, .ctors sections are output in
   // either .ctors or .init_array sections, and .dtors sections are
   // output in either .dtors or .fini_array sections.
@@ -4611,7 +5636,7 @@ Layout::find_or_add_kept_section(const std::string& name,
                                 unsigned int shndx,
                                 bool is_comdat,
                                 bool is_group_name,
-                                 Kept_section** kept_section)
+                                Kept_section** kept_section)
 {
   // It's normal to see a couple of entries here, for the x86 thunk
   // sections.  If we see more than a few, we're linking a C++
@@ -4650,12 +5675,12 @@ Layout::find_or_add_kept_section(const std::string& name,
       // If the kept group is from a plugin object, and we're in the
       // replacement phase, accept the new one as a replacement.
       if (ins.first->second.object() == NULL
-          && parameters->options().plugins()->in_replacement_phase())
-        {
+         && parameters->options().plugins()->in_replacement_phase())
+       {
          ins.first->second.set_object(object);
          ins.first->second.set_shndx(shndx);
-          return true;
-        }
+         return true;
+       }
       return false;
     }
   else if (is_group_name)
@@ -4687,6 +5712,19 @@ Layout::get_allocated_sections(Section_list* section_list) const
       section_list->push_back(*p);
 }
 
+// Store the executable sections into the section list.
+
+void
+Layout::get_executable_sections(Section_list* section_list) const
+{
+  for (Section_list::const_iterator p = this->section_list_.begin();
+       p != this->section_list_.end();
+       ++p)
+    if (((*p)->flags() & (elfcpp::SHF_ALLOC | elfcpp::SHF_EXECINSTR))
+       == (elfcpp::SHF_ALLOC | elfcpp::SHF_EXECINSTR))
+      section_list->push_back(*p);
+}
+
 // Create an output segment.
 
 Output_segment*
@@ -4788,6 +5826,13 @@ Layout::write_data(const Symbol_table* symtab, Output_file* of) const
        p != this->special_output_list_.end();
        ++p)
     (*p)->write(of);
+
+  // Write out the Output_data which are not in an Output_section
+  // and are regenerated in each iteration of relaxation.
+  for (Data_list::const_iterator p = this->relax_output_list_.begin();
+       p != this->relax_output_list_.end();
+       ++p)
+    (*p)->write(of);
 }
 
 // Write out the Output_sections which can only be written after the
@@ -4828,44 +5873,49 @@ Layout::write_sections_after_input_sections(Output_file* of)
   this->section_headers_->write(of);
 }
 
-// If the build ID requires computing a checksum, do so here, and
-// write it out.  We compute a checksum over the entire file because
-// that is simplest.
+// If a tree-style build ID was requested, the parallel part of that computation
+// is already done, and the final hash-of-hashes is computed here.  For other
+// types of build IDs, all the work is done here.
 
 void
-Layout::write_build_id(Output_file* of) const
+Layout::write_build_id(Output_file* of, unsigned char* array_of_hashes,
+                      size_t size_of_hashes) const
 {
   if (this->build_id_note_ == NULL)
     return;
 
-  const unsigned char* iv = of->get_input_view(0, this->output_file_size_);
-
   unsigned char* ov = of->get_output_view(this->build_id_note_->offset(),
                                          this->build_id_note_->data_size());
 
-  const char* style = parameters->options().build_id();
-  if (strcmp(style, "sha1") == 0)
+  if (array_of_hashes == NULL)
     {
-      sha1_ctx ctx;
-      sha1_init_ctx(&ctx);
-      sha1_process_bytes(iv, this->output_file_size_, &ctx);
-      sha1_finish_ctx(&ctx, ov);
+      const size_t output_file_size = this->output_file_size();
+      const unsigned char* iv = of->get_input_view(0, output_file_size);
+      const char* style = parameters->options().build_id();
+
+      // If we get here with style == "tree" then the output must be
+      // too small for chunking, and we use SHA-1 in that case.
+      if ((strcmp(style, "sha1") == 0) || (strcmp(style, "tree") == 0))
+       sha1_buffer(reinterpret_cast<const char*>(iv), output_file_size, ov);
+      else if (strcmp(style, "md5") == 0)
+       md5_buffer(reinterpret_cast<const char*>(iv), output_file_size, ov);
+      else
+       gold_unreachable();
+
+      of->free_input_view(0, output_file_size, iv);
     }
-  else if (strcmp(style, "md5") == 0)
+  else
     {
-      md5_ctx ctx;
-      md5_init_ctx(&ctx);
-      md5_process_bytes(iv, this->output_file_size_, &ctx);
-      md5_finish_ctx(&ctx, ov);
+      // Non-overlapping substrings of the output file have been hashed.
+      // Compute SHA-1 hash of the hashes.
+      sha1_buffer(reinterpret_cast<const char*>(array_of_hashes),
+                 size_of_hashes, ov);
+      delete[] array_of_hashes;
     }
-  else
-    gold_unreachable();
 
   of->write_output_view(this->build_id_note_->offset(),
                        this->build_id_note_->data_size(),
                        ov);
-
-  of->free_input_view(0, this->output_file_size_, iv);
 }
 
 // Write out a binary file.  This is called after the link is
@@ -4926,6 +5976,10 @@ Layout::print_to_mapfile(Mapfile* mapfile) const
        p != this->segment_list_.end();
        ++p)
     (*p)->print_sections_to_mapfile(mapfile);
+  for (Section_list::const_iterator p = this->unattached_section_list_.begin();
+       p != this->unattached_section_list_.end();
+       ++p)
+    (*p)->print_to_mapfile(mapfile);
 }
 
 // Print statistical information to stderr.  This is used for --stats.
@@ -4960,6 +6014,8 @@ void
 Write_sections_task::locks(Task_locker* tl)
 {
   tl->add(this, this->output_sections_blocker_);
+  if (this->input_sections_blocker_ != NULL)
+    tl->add(this, this->input_sections_blocker_);
   tl->add(this, this->final_blocker_);
 }
 
@@ -5053,20 +6109,78 @@ Write_after_input_sections_task::run(Workqueue*)
   this->layout_->write_sections_after_input_sections(this->of_);
 }
 
+// Build IDs can be computed as a "flat" sha1 or md5 of a string of bytes,
+// or as a "tree" where each chunk of the string is hashed and then those
+// hashes are put into a (much smaller) string which is hashed with sha1.
+// We compute a checksum over the entire file because that is simplest.
+
+void
+Build_id_task_runner::run(Workqueue* workqueue, const Task*)
+{
+  Task_token* post_hash_tasks_blocker = new Task_token(true);
+  const Layout* layout = this->layout_;
+  Output_file* of = this->of_;
+  const size_t filesize = (layout->output_file_size() <= 0 ? 0
+                          : static_cast<size_t>(layout->output_file_size()));
+  unsigned char* array_of_hashes = NULL;
+  size_t size_of_hashes = 0;
+
+  if (strcmp(this->options_->build_id(), "tree") == 0
+      && this->options_->build_id_chunk_size_for_treehash() > 0
+      && filesize > 0
+      && (filesize >= this->options_->build_id_min_file_size_for_treehash()))
+    {
+      static const size_t MD5_OUTPUT_SIZE_IN_BYTES = 16;
+      const size_t chunk_size =
+         this->options_->build_id_chunk_size_for_treehash();
+      const size_t num_hashes = ((filesize - 1) / chunk_size) + 1;
+      post_hash_tasks_blocker->add_blockers(num_hashes);
+      size_of_hashes = num_hashes * MD5_OUTPUT_SIZE_IN_BYTES;
+      array_of_hashes = new unsigned char[size_of_hashes];
+      unsigned char *dst = array_of_hashes;
+      for (size_t i = 0, src_offset = 0; i < num_hashes;
+          i++, dst += MD5_OUTPUT_SIZE_IN_BYTES, src_offset += chunk_size)
+       {
+         size_t size = std::min(chunk_size, filesize - src_offset);
+         workqueue->queue(new Hash_task(of,
+                                        src_offset,
+                                        size,
+                                        dst,
+                                        post_hash_tasks_blocker));
+       }
+    }
+
+  // Queue the final task to write the build id and close the output file.
+  workqueue->queue(new Task_function(new Close_task_runner(this->options_,
+                                                          layout,
+                                                          of,
+                                                          array_of_hashes,
+                                                          size_of_hashes),
+                                    post_hash_tasks_blocker,
+                                    "Task_function Close_task_runner"));
+}
+
 // Close_task_runner methods.
 
-// Run the task--close the file.
+// Finish up the build ID computation, if necessary, and write a binary file,
+// if necessary.  Then close the output file.
 
 void
 Close_task_runner::run(Workqueue*, const Task*)
 {
-  // If we need to compute a checksum for the BUILD if, we do so here.
-  this->layout_->write_build_id(this->of_);
+  // At this point the multi-threaded part of the build ID computation,
+  // if any, is done.  See Build_id_task_runner.
+  this->layout_->write_build_id(this->of_, this->array_of_hashes_,
+                               this->size_of_hashes_);
 
   // If we've been asked to create a binary file, we do so here.
   if (this->options_->oformat_enum() != General_options::OBJECT_FORMAT_ELF)
     this->layout_->write_binary(this->of_);
 
+  if (this->options_->dependency_file())
+    File_read::write_dependency_file(this->options_->dependency_file(),
+                                    this->options_->output_file_name());
+
   this->of_->close();
 }
 
@@ -5112,7 +6226,7 @@ Layout::layout<32, false>(Sized_relobj_file<32, false>* object,
                          unsigned int shndx,
                          const char* name,
                          const elfcpp::Shdr<32, false>& shdr,
-                         unsigned int, unsigned int, off_t*);
+                         unsigned int, unsigned int, unsigned int, off_t*);
 #endif
 
 #ifdef HAVE_TARGET_32_BIG
@@ -5122,7 +6236,7 @@ Layout::layout<32, true>(Sized_relobj_file<32, true>* object,
                         unsigned int shndx,
                         const char* name,
                         const elfcpp::Shdr<32, true>& shdr,
-                        unsigned int, unsigned int, off_t*);
+                        unsigned int, unsigned int, unsigned int, off_t*);
 #endif
 
 #ifdef HAVE_TARGET_64_LITTLE
@@ -5132,7 +6246,7 @@ Layout::layout<64, false>(Sized_relobj_file<64, false>* object,
                          unsigned int shndx,
                          const char* name,
                          const elfcpp::Shdr<64, false>& shdr,
-                         unsigned int, unsigned int, off_t*);
+                         unsigned int, unsigned int, unsigned int, off_t*);
 #endif
 
 #ifdef HAVE_TARGET_64_BIG
@@ -5142,7 +6256,7 @@ Layout::layout<64, true>(Sized_relobj_file<64, true>* object,
                         unsigned int shndx,
                         const char* name,
                         const elfcpp::Shdr<64, true>& shdr,
-                        unsigned int, unsigned int, off_t*);
+                        unsigned int, unsigned int, unsigned int, off_t*);
 #endif
 
 #ifdef HAVE_TARGET_32_LITTLE
@@ -5297,4 +6411,52 @@ Layout::layout_eh_frame<64, true>(Sized_relobj_file<64, true>* object,
                                  off_t* off);
 #endif
 
+#ifdef HAVE_TARGET_32_LITTLE
+template
+void
+Layout::add_to_gdb_index(bool is_type_unit,
+                        Sized_relobj<32, false>* object,
+                        const unsigned char* symbols,
+                        off_t symbols_size,
+                        unsigned int shndx,
+                        unsigned int reloc_shndx,
+                        unsigned int reloc_type);
+#endif
+
+#ifdef HAVE_TARGET_32_BIG
+template
+void
+Layout::add_to_gdb_index(bool is_type_unit,
+                        Sized_relobj<32, true>* object,
+                        const unsigned char* symbols,
+                        off_t symbols_size,
+                        unsigned int shndx,
+                        unsigned int reloc_shndx,
+                        unsigned int reloc_type);
+#endif
+
+#ifdef HAVE_TARGET_64_LITTLE
+template
+void
+Layout::add_to_gdb_index(bool is_type_unit,
+                        Sized_relobj<64, false>* object,
+                        const unsigned char* symbols,
+                        off_t symbols_size,
+                        unsigned int shndx,
+                        unsigned int reloc_shndx,
+                        unsigned int reloc_type);
+#endif
+
+#ifdef HAVE_TARGET_64_BIG
+template
+void
+Layout::add_to_gdb_index(bool is_type_unit,
+                        Sized_relobj<64, true>* object,
+                        const unsigned char* symbols,
+                        off_t symbols_size,
+                        unsigned int shndx,
+                        unsigned int reloc_shndx,
+                        unsigned int reloc_type);
+#endif
+
 } // End namespace gold.