PR gold/11658
[binutils-gdb.git] / gold / output.cc
index f2ec6ee906ede77e1ddd37cc908ba093aaba087e..329a4beda7699397433793a640305fd0a5609123 100644 (file)
@@ -30,7 +30,7 @@
 #include <sys/mman.h>
 #include <sys/stat.h>
 #include <algorithm>
-#include "libiberty.h"   // for unlink_if_ordinary()
+#include "libiberty.h"
 
 #include "parameters.h"
 #include "object.h"
 # define MAP_ANONYMOUS  MAP_ANON
 #endif
 
+#ifndef HAVE_POSIX_FALLOCATE
+// A dummy, non general, version of posix_fallocate.  Here we just set
+// the file size and hope that there is enough disk space.  FIXME: We
+// could allocate disk space by walking block by block and writing a
+// zero byte into each block.
+static int
+posix_fallocate(int o, off_t offset, off_t len)
+{
+  return ftruncate(o, offset + len);
+}
+#endif // !defined(HAVE_POSIX_FALLOCATE)
+
 namespace gold
 {
 
@@ -96,26 +108,35 @@ Output_section_headers::Output_section_headers(
     unattached_section_list_(unattached_section_list),
     secnamepool_(secnamepool),
     shstrtab_section_(shstrtab_section)
+{
+}
+
+// Compute the current data size.
+
+off_t
+Output_section_headers::do_size() const
 {
   // Count all the sections.  Start with 1 for the null section.
   off_t count = 1;
   if (!parameters->options().relocatable())
     {
-      for (Layout::Segment_list::const_iterator p = segment_list->begin();
-          p != segment_list->end();
+      for (Layout::Segment_list::const_iterator p =
+            this->segment_list_->begin();
+          p != this->segment_list_->end();
           ++p)
        if ((*p)->type() == elfcpp::PT_LOAD)
          count += (*p)->output_section_count();
     }
   else
     {
-      for (Layout::Section_list::const_iterator p = section_list->begin();
-          p != section_list->end();
+      for (Layout::Section_list::const_iterator p =
+            this->section_list_->begin();
+          p != this->section_list_->end();
           ++p)
        if (((*p)->flags() & elfcpp::SHF_ALLOC) != 0)
          ++count;
     }
-  count += unattached_section_list->size();
+  count += this->unattached_section_list_->size();
 
   const int size = parameters->target().get_size();
   int shdr_size;
@@ -126,7 +147,7 @@ Output_section_headers::Output_section_headers(
   else
     gold_unreachable();
 
-  this->set_data_size(count * shdr_size);
+  return count * shdr_size;
 }
 
 // Write out the section headers.
@@ -192,7 +213,9 @@ Output_section_headers::do_sized_write(Output_file* of)
     else
       oshdr.put_sh_link(shstrndx);
 
-    oshdr.put_sh_info(0);
+    size_t segment_count = this->segment_list_->size();
+    oshdr.put_sh_info(segment_count >= elfcpp::PN_XNUM ? segment_count : 0);
+
     oshdr.put_sh_addralign(0);
     oshdr.put_sh_entsize(0);
   }
@@ -257,16 +280,6 @@ Output_segment_headers::Output_segment_headers(
     const Layout::Segment_list& segment_list)
   : segment_list_(segment_list)
 {
-  const int size = parameters->target().get_size();
-  int phdr_size;
-  if (size == 32)
-    phdr_size = elfcpp::Elf_sizes<32>::phdr_size;
-  else if (size == 64)
-    phdr_size = elfcpp::Elf_sizes<64>::phdr_size;
-  else
-    gold_unreachable();
-
-  this->set_data_size(segment_list.size() * phdr_size);
 }
 
 void
@@ -323,6 +336,21 @@ Output_segment_headers::do_sized_write(Output_file* of)
   of->write_output_view(this->offset(), all_phdrs_size, view);
 }
 
+off_t
+Output_segment_headers::do_size() const
+{
+  const int size = parameters->target().get_size();
+  int phdr_size;
+  if (size == 32)
+    phdr_size = elfcpp::Elf_sizes<32>::phdr_size;
+  else if (size == 64)
+    phdr_size = elfcpp::Elf_sizes<64>::phdr_size;
+  else
+    gold_unreachable();
+
+  return this->segment_list_.size() * phdr_size;
+}
+
 // Output_file_header methods.
 
 Output_file_header::Output_file_header(const Target* target,
@@ -336,16 +364,7 @@ Output_file_header::Output_file_header(const Target* target,
     shstrtab_(NULL),
     entry_(entry)
 {
-  const int size = parameters->target().get_size();
-  int ehdr_size;
-  if (size == 32)
-    ehdr_size = elfcpp::Elf_sizes<32>::ehdr_size;
-  else if (size == 64)
-    ehdr_size = elfcpp::Elf_sizes<64>::ehdr_size;
-  else
-    gold_unreachable();
-
-  this->set_data_size(ehdr_size);
+  this->set_data_size(this->do_size());
 }
 
 // Set the section table information for a file header.
@@ -420,13 +439,12 @@ Output_file_header::do_sized_write(Output_file* of)
                              ? elfcpp::ELFDATA2MSB
                              : elfcpp::ELFDATA2LSB);
   e_ident[elfcpp::EI_VERSION] = elfcpp::EV_CURRENT;
-  // FIXME: Some targets may need to set EI_OSABI and EI_ABIVERSION.
   oehdr.put_e_ident(e_ident);
 
   elfcpp::ET e_type;
   if (parameters->options().relocatable())
     e_type = elfcpp::ET_REL;
-  else if (parameters->options().shared())
+  else if (parameters->options().output_is_position_independent())
     e_type = elfcpp::ET_DYN;
   else
     e_type = elfcpp::ET_EXEC;
@@ -443,10 +461,7 @@ Output_file_header::do_sized_write(Output_file* of)
     oehdr.put_e_phoff(this->segment_header_->offset());
 
   oehdr.put_e_shoff(this->section_header_->offset());
-
-  // FIXME: The target needs to set the flags.
-  oehdr.put_e_flags(0);
-
+  oehdr.put_e_flags(this->target_->processor_specific_flags());
   oehdr.put_e_ehsize(elfcpp::Elf_sizes<size>::ehdr_size);
 
   if (this->segment_header_ == NULL)
@@ -457,8 +472,11 @@ Output_file_header::do_sized_write(Output_file* of)
   else
     {
       oehdr.put_e_phentsize(elfcpp::Elf_sizes<size>::phdr_size);
-      oehdr.put_e_phnum(this->segment_header_->data_size()
-                       / elfcpp::Elf_sizes<size>::phdr_size);
+      size_t phnum = (this->segment_header_->data_size()
+                     / elfcpp::Elf_sizes<size>::phdr_size);
+      if (phnum > elfcpp::PN_XNUM)
+       phnum = elfcpp::PN_XNUM;
+      oehdr.put_e_phnum(phnum);
     }
 
   oehdr.put_e_shentsize(elfcpp::Elf_sizes<size>::shdr_size);
@@ -477,6 +495,10 @@ Output_file_header::do_sized_write(Output_file* of)
   else
     oehdr.put_e_shstrndx(elfcpp::SHN_XINDEX);
 
+  // Let the target adjust the ELF header, e.g., to set EI_OSABI in
+  // the e_ident field.
+  parameters->target().adjust_elf_header(view, ehdr_size);
+
   of->write_output_view(0, ehdr_size, view);
 }
 
@@ -524,6 +546,20 @@ Output_file_header::entry()
   return v;
 }
 
+// Compute the current data size.
+
+off_t
+Output_file_header::do_size() const
+{
+  const int size = parameters->target().get_size();
+  if (size == 32)
+    return elfcpp::Elf_sizes<32>::ehdr_size;
+  else if (size == 64)
+    return elfcpp::Elf_sizes<64>::ehdr_size;
+  else
+    gold_unreachable();
+}
+
 // Output_data_const methods.
 
 void
@@ -602,9 +638,11 @@ Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::Output_reloc(
     unsigned int type,
     Output_data* od,
     Address address,
-    bool is_relative)
+    bool is_relative,
+    bool is_symbolless)
   : address_(address), local_sym_index_(GSYM_CODE), type_(type),
-    is_relative_(is_relative), is_section_symbol_(false), shndx_(INVALID_CODE)
+    is_relative_(is_relative), is_symbolless_(is_symbolless),
+    is_section_symbol_(false), shndx_(INVALID_CODE)
 {
   // this->type_ is a bitfield; make sure TYPE fits.
   gold_assert(this->type_ == type);
@@ -621,9 +659,11 @@ Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::Output_reloc(
     Sized_relobj<size, big_endian>* relobj,
     unsigned int shndx,
     Address address,
-    bool is_relative)
+    bool is_relative,
+    bool is_symbolless)
   : address_(address), local_sym_index_(GSYM_CODE), type_(type),
-    is_relative_(is_relative), is_section_symbol_(false), shndx_(shndx)
+    is_relative_(is_relative), is_symbolless_(is_symbolless),
+    is_section_symbol_(false), shndx_(shndx)
 {
   gold_assert(shndx != INVALID_CODE);
   // this->type_ is a bitfield; make sure TYPE fits.
@@ -644,10 +684,11 @@ Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::Output_reloc(
     Output_data* od,
     Address address,
     bool is_relative,
+    bool is_symbolless,
     bool is_section_symbol)
   : address_(address), local_sym_index_(local_sym_index), type_(type),
-    is_relative_(is_relative), is_section_symbol_(is_section_symbol),
-    shndx_(INVALID_CODE)
+    is_relative_(is_relative), is_symbolless_(is_symbolless),
+    is_section_symbol_(is_section_symbol), shndx_(INVALID_CODE)
 {
   gold_assert(local_sym_index != GSYM_CODE
               && local_sym_index != INVALID_CODE);
@@ -667,10 +708,11 @@ Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::Output_reloc(
     unsigned int shndx,
     Address address,
     bool is_relative,
+    bool is_symbolless,
     bool is_section_symbol)
   : address_(address), local_sym_index_(local_sym_index), type_(type),
-    is_relative_(is_relative), is_section_symbol_(is_section_symbol),
-    shndx_(shndx)
+    is_relative_(is_relative), is_symbolless_(is_symbolless),
+    is_section_symbol_(is_section_symbol), shndx_(shndx)
 {
   gold_assert(local_sym_index != GSYM_CODE
               && local_sym_index != INVALID_CODE);
@@ -692,7 +734,8 @@ Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::Output_reloc(
     Output_data* od,
     Address address)
   : address_(address), local_sym_index_(SECTION_CODE), type_(type),
-    is_relative_(false), is_section_symbol_(true), shndx_(INVALID_CODE)
+    is_relative_(false), is_symbolless_(false),
+    is_section_symbol_(true), shndx_(INVALID_CODE)
 {
   // this->type_ is a bitfield; make sure TYPE fits.
   gold_assert(this->type_ == type);
@@ -712,7 +755,8 @@ Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::Output_reloc(
     unsigned int shndx,
     Address address)
   : address_(address), local_sym_index_(SECTION_CODE), type_(type),
-    is_relative_(false), is_section_symbol_(true), shndx_(shndx)
+    is_relative_(false), is_symbolless_(false),
+    is_section_symbol_(true), shndx_(shndx)
 {
   gold_assert(shndx != INVALID_CODE);
   // this->type_ is a bitfield; make sure TYPE fits.
@@ -725,6 +769,76 @@ Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::Output_reloc(
     os->set_needs_symtab_index();
 }
 
+// An absolute relocation.
+
+template<bool dynamic, int size, bool big_endian>
+Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::Output_reloc(
+    unsigned int type,
+    Output_data* od,
+    Address address)
+  : address_(address), local_sym_index_(0), type_(type),
+    is_relative_(false), is_symbolless_(false),
+    is_section_symbol_(false), shndx_(INVALID_CODE)
+{
+  // this->type_ is a bitfield; make sure TYPE fits.
+  gold_assert(this->type_ == type);
+  this->u1_.relobj = NULL;
+  this->u2_.od = od;
+}
+
+template<bool dynamic, int size, bool big_endian>
+Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::Output_reloc(
+    unsigned int type,
+    Sized_relobj<size, big_endian>* relobj,
+    unsigned int shndx,
+    Address address)
+  : address_(address), local_sym_index_(0), type_(type),
+    is_relative_(false), is_symbolless_(false),
+    is_section_symbol_(false), shndx_(shndx)
+{
+  gold_assert(shndx != INVALID_CODE);
+  // this->type_ is a bitfield; make sure TYPE fits.
+  gold_assert(this->type_ == type);
+  this->u1_.relobj = NULL;
+  this->u2_.relobj = relobj;
+}
+
+// A target specific relocation.
+
+template<bool dynamic, int size, bool big_endian>
+Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::Output_reloc(
+    unsigned int type,
+    void* arg,
+    Output_data* od,
+    Address address)
+  : address_(address), local_sym_index_(TARGET_CODE), type_(type),
+    is_relative_(false), is_symbolless_(false),
+    is_section_symbol_(false), shndx_(INVALID_CODE)
+{
+  // this->type_ is a bitfield; make sure TYPE fits.
+  gold_assert(this->type_ == type);
+  this->u1_.arg = arg;
+  this->u2_.od = od;
+}
+
+template<bool dynamic, int size, bool big_endian>
+Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::Output_reloc(
+    unsigned int type,
+    void* arg,
+    Sized_relobj<size, big_endian>* relobj,
+    unsigned int shndx,
+    Address address)
+  : address_(address), local_sym_index_(TARGET_CODE), type_(type),
+    is_relative_(false), is_symbolless_(false),
+    is_section_symbol_(false), shndx_(shndx)
+{
+  gold_assert(shndx != INVALID_CODE);
+  // this->type_ is a bitfield; make sure TYPE fits.
+  gold_assert(this->type_ == type);
+  this->u1_.arg = arg;
+  this->u2_.relobj = relobj;
+}
+
 // Record that we need a dynamic symbol index for this relocation.
 
 template<bool dynamic, int size, bool big_endian>
@@ -732,7 +846,7 @@ void
 Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::
 set_needs_dynsym_index()
 {
-  if (this->is_relative_)
+  if (this->is_symbolless_)
     return;
   switch (this->local_sym_index_)
     {
@@ -747,6 +861,10 @@ set_needs_dynsym_index()
       this->u1_.os->set_needs_dynsym_index();
       break;
 
+    case TARGET_CODE:
+      // The target must take care of this if necessary.
+      break;
+
     case 0:
       break;
 
@@ -770,6 +888,8 @@ Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::get_symbol_index()
   const
 {
   unsigned int index;
+  if (this->is_symbolless_)
+    return 0;
   switch (this->local_sym_index_)
     {
     case INVALID_CODE:
@@ -791,6 +911,11 @@ Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::get_symbol_index()
        index = this->u1_.os->symtab_index();
       break;
 
+    case TARGET_CODE:
+      index = parameters->target().reloc_symbol_index(this->u1_.arg,
+                                                     this->type_);
+      break;
+
     case 0:
       // Relocations without symbols use a symbol index of 0.
       index = 0;
@@ -832,7 +957,9 @@ Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::
 {
   gold_assert(this->local_sym_index_ != GSYM_CODE
               && this->local_sym_index_ != SECTION_CODE
+             && this->local_sym_index_ != TARGET_CODE
               && this->local_sym_index_ != INVALID_CODE
+             && this->local_sym_index_ != 0
               && this->is_section_symbol_);
   const unsigned int lsi = this->local_sym_index_;
   Output_section* os = this->u1_.relobj->output_section(lsi);
@@ -882,7 +1009,7 @@ Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::write_rel(
     Write_rel* wr) const
 {
   wr->put_r_offset(this->get_address());
-  unsigned int sym_index = this->is_relative_ ? 0 : this->get_symbol_index();
+  unsigned int sym_index = this->get_symbol_index();
   wr->put_r_info(elfcpp::elf_r_info<size>(sym_index, this->type_));
 }
 
@@ -911,7 +1038,9 @@ Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::symbol_value(
       return sym->value() + addend;
     }
   gold_assert(this->local_sym_index_ != SECTION_CODE
+             && this->local_sym_index_ != TARGET_CODE
               && this->local_sym_index_ != INVALID_CODE
+             && this->local_sym_index_ != 0
               && !this->is_section_symbol_);
   const unsigned int lsi = this->local_sym_index_;
   const Symbol_value<size>* symval = this->u1_.relobj->local_symbol(lsi);
@@ -979,7 +1108,10 @@ Output_reloc<elfcpp::SHT_RELA, dynamic, size, big_endian>::write(
   elfcpp::Rela_write<size, big_endian> orel(pov);
   this->rel_.write_rel(&orel);
   Addend addend = this->addend_;
-  if (this->rel_.is_relative())
+  if (this->rel_.is_target_specific())
+    addend = parameters->target().reloc_addend(this->rel_.target_arg(),
+                                              this->rel_.type(), addend);
+  else if (this->rel_.is_symbolless())
     addend = this->rel_.symbol_value(addend);
   else if (this->rel_.is_local_section_symbol())
     addend = this->rel_.local_section_offset(addend);
@@ -1018,7 +1150,7 @@ Output_data_reloc_base<sh_type, dynamic, size, big_endian>::do_write(
   const off_t oview_size = this->data_size();
   unsigned char* const oview = of->get_output_view(off, oview_size);
 
-  if (this->sort_relocs_)
+  if (this->sort_relocs())
     {
       gold_assert(dynamic);
       std::sort(this->relocs_.begin(), this->relocs_.end(),
@@ -1060,7 +1192,7 @@ Output_data_group<size, big_endian>::Output_data_group(
     section_size_type entry_count,
     elfcpp::Elf_Word flags,
     std::vector<unsigned int>* input_shndxes)
-  : Output_section_data(entry_count * 4, 4),
+  : Output_section_data(entry_count * 4, 4, false),
     relobj_(relobj),
     flags_(flags)
 {
@@ -1442,6 +1574,8 @@ Output_data_dynamic::Dynamic_entry::write(
 
     case DYNAMIC_SECTION_SIZE:
       val = this->u_.od->data_size();
+      if (this->od2 != NULL)
+       val += this->od2->data_size();
       break;
 
     case DYNAMIC_SYMBOL:
@@ -1486,8 +1620,15 @@ Output_data_dynamic::do_adjust_output_section(Output_section* os)
 void
 Output_data_dynamic::set_final_data_size()
 {
-  // Add the terminating entry.
-  this->add_constant(elfcpp::DT_NULL, 0);
+  // Add the terminating entry if it hasn't been added.
+  // Because of relaxation, we can run this multiple times.
+  if (this->entries_.empty() || this->entries_.back().tag() != elfcpp::DT_NULL)
+    {
+      int extra = parameters->options().spare_dynamic_tags();
+      for (int i = 0; i < extra; ++i)
+       this->add_constant(elfcpp::DT_NULL, 0);
+      this->add_constant(elfcpp::DT_NULL, 0);
+    }
 
   int dyn_size;
   if (parameters->target().get_size() == 32)
@@ -1587,7 +1728,11 @@ Output_symtab_xindex::endian_do_write(unsigned char* const oview)
   for (Xindex_entries::const_iterator p = this->entries_.begin();
        p != this->entries_.end();
        ++p)
-    elfcpp::Swap<32, big_endian>::writeval(oview + p->first * 4, p->second);
+    {
+      unsigned int symndx = p->first;
+      gold_assert(symndx * 4 < this->data_size());
+      elfcpp::Swap<32, big_endian>::writeval(oview + symndx * 4, p->second);
+    }
 }
 
 // Output_section::Input_section methods.
@@ -1604,6 +1749,42 @@ Output_section::Input_section::data_size() const
     return this->u2_.posd->data_size();
 }
 
+// Return the object for an input section.
+
+Relobj*
+Output_section::Input_section::relobj() const
+{
+  if (this->is_input_section())
+    return this->u2_.object;
+  else if (this->is_merge_section())
+    {
+      gold_assert(this->u2_.pomb->first_relobj() != NULL);
+      return this->u2_.pomb->first_relobj();
+    }
+  else if (this->is_relaxed_input_section())
+    return this->u2_.poris->relobj();
+  else
+    gold_unreachable();
+}
+
+// Return the input section index for an input section.
+
+unsigned int
+Output_section::Input_section::shndx() const
+{
+  if (this->is_input_section())
+    return this->shndx_;
+  else if (this->is_merge_section())
+    {
+      gold_assert(this->u2_.pomb->first_relobj() != NULL);
+      return this->u2_.pomb->first_shndx();
+    }
+  else if (this->is_relaxed_input_section())
+    return this->u2_.poris->shndx();
+  else
+    gold_unreachable();
+}
+
 // Set the address and file offset.
 
 void
@@ -1705,6 +1886,14 @@ Output_section::Input_section::print_to_mapfile(Mapfile* mapfile) const
       this->u2_.posd->print_to_mapfile(mapfile);
       break;
 
+    case RELAXED_INPUT_SECTION_CODE:
+      {
+        Output_relaxed_input_section* relaxed_section =
+         this->relaxed_input_section();
+        mapfile->print_input_section(relaxed_section->relobj(),
+                                    relaxed_section->shndx());
+      }
+      break;
     default:
       mapfile->print_input_section(this->u2_.object, this->shndx_);
       break;
@@ -1744,12 +1933,25 @@ Output_section::Output_section(const char* name, elfcpp::Elf_Word type,
     found_in_sections_clause_(false),
     has_load_address_(false),
     info_uses_section_index_(false),
+    input_section_order_specified_(false),
     may_sort_attached_input_sections_(false),
     must_sort_attached_input_sections_(false),
     attached_input_sections_are_sorted_(false),
     is_relro_(false),
     is_relro_local_(false),
-    tls_offset_(0)
+    is_last_relro_(false),
+    is_first_non_relro_(false),
+    is_small_section_(false),
+    is_large_section_(false),
+    is_interp_(false),
+    is_dynamic_linker_section_(false),
+    generate_code_fills_at_write_(false),
+    is_entsize_zero_(false),
+    section_offsets_need_adjustment_(false),
+    is_noload_(false),
+    tls_offset_(0),
+    checkpoint_(NULL),
+    lookup_maps_(new Output_section_lookup_maps)
 {
   // An unallocated section has no address.  Forcing this means that
   // we don't need special treatment for symbols defined in debug
@@ -1760,6 +1962,7 @@ Output_section::Output_section(const char* name, elfcpp::Elf_Word type,
 
 Output_section::~Output_section()
 {
+  delete this->checkpoint_;
 }
 
 // Set the entry size.
@@ -1767,10 +1970,15 @@ Output_section::~Output_section()
 void
 Output_section::set_entsize(uint64_t v)
 {
-  if (this->entsize_ == 0)
+  if (this->is_entsize_zero_)
+    ;
+  else if (this->entsize_ == 0)
     this->entsize_ = v;
-  else
-    gold_assert(this->entsize_ == v);
+  else if (this->entsize_ != v)
+    {
+      this->entsize_ = 0;
+      this->is_entsize_zero_ = 1;
+    }
 }
 
 // Add the input section SHNDX, with header SHDR, named SECNAME, in
@@ -1787,7 +1995,8 @@ Output_section::set_entsize(uint64_t v)
 
 template<int size, bool big_endian>
 off_t
-Output_section::add_input_section(Sized_relobj<size, big_endian>* object,
+Output_section::add_input_section(Layout* layout,
+                                 Sized_relobj<size, big_endian>* object,
                                  unsigned int shndx,
                                  const char* secname,
                                  const elfcpp::Shdr<size, big_endian>& shdr,
@@ -1806,8 +2015,6 @@ Output_section::add_input_section(Sized_relobj<size, big_endian>* object,
     this->addralign_ = addralign;
 
   typename elfcpp::Elf_types<size>::Elf_WXword sh_flags = shdr.get_sh_flags();
-  this->update_flags_for_input_section(sh_flags);
-
   uint64_t entsize = shdr.get_sh_entsize();
 
   // .debug_str is a mergeable string section, but is not always so
@@ -1818,6 +2025,9 @@ Output_section::add_input_section(Sized_relobj<size, big_endian>* object,
       entsize = 1;
     }
 
+  this->update_flags_for_input_section(sh_flags);
+  this->set_entsize(entsize);
+
   // If this is a SHF_MERGE section, we pass all the input sections to
   // a Output_data_merge.  We don't try to handle relocations for such
   // a section.  We don't try to handle empty merge sections--they
@@ -1826,8 +2036,12 @@ Output_section::add_input_section(Sized_relobj<size, big_endian>* object,
       && reloc_shndx == 0
       && shdr.get_sh_size() > 0)
     {
-      if (this->add_merge_input_section(object, shndx, sh_flags,
-                                       entsize, addralign))
+      // Keep information about merged input sections for rebuilding fast
+      // lookup maps if we have sections-script or we do relaxation.
+      bool keeps_input_sections =
+       have_sections_script || parameters->target().may_relax();
+      if (this->add_merge_input_section(object, shndx, sh_flags, entsize,
+                                       addralign, keeps_input_sections))
        {
          // Tell the relocation routines that they need to call the
          // output_offset method to determine the final address.
@@ -1839,10 +2053,24 @@ Output_section::add_input_section(Sized_relobj<size, big_endian>* object,
   off_t aligned_offset_in_section = align_address(offset_in_section,
                                                   addralign);
 
+  // Determine if we want to delay code-fill generation until the output
+  // section is written.  When the target is relaxing, we want to delay fill
+  // generating to avoid adjusting them during relaxation.
+  if (!this->generate_code_fills_at_write_
+      && !have_sections_script
+      && (sh_flags & elfcpp::SHF_EXECINSTR) != 0
+      && parameters->target().has_code_fill()
+      && parameters->target().may_relax())
+    {
+      gold_assert(this->fills_.empty());
+      this->generate_code_fills_at_write_ = true;
+    }
+
   if (aligned_offset_in_section > offset_in_section
+      && !this->generate_code_fills_at_write_
       && !have_sections_script
       && (sh_flags & elfcpp::SHF_EXECINSTR) != 0
-      && object->target()->has_code_fill())
+      && parameters->target().has_code_fill())
     {
       // We need to add some fill data.  Using fill_list_ when
       // possible is an optimization, since we will often have fill
@@ -1852,9 +2080,7 @@ Output_section::add_input_section(Sized_relobj<size, big_endian>* object,
         this->fills_.push_back(Fill(offset_in_section, fill_len));
       else
         {
-          // FIXME: When relaxing, the size needs to adjust to
-          // maintain a constant alignment.
-          std::string fill_data(object->target()->code_fill(fill_len));
+          std::string fill_data(parameters->target().code_fill(fill_len));
           Output_data_const* odc = new Output_data_const(fill_data, 1);
           this->input_sections_.push_back(Input_section(odc));
         }
@@ -1866,16 +2092,30 @@ Output_section::add_input_section(Sized_relobj<size, big_endian>* object,
   // We need to keep track of this section if we are already keeping
   // track of sections, or if we are relaxing.  Also, if this is a
   // section which requires sorting, or which may require sorting in
-  // the future, we keep track of the sections.  FIXME: Add test for
-  // relaxing.
+  // the future, we keep track of the sections.  If the
+  // --section-ordering-file option is used to specify the order of
+  // sections, we need to keep track of sections.
   if (have_sections_script
       || !this->input_sections_.empty()
       || this->may_sort_attached_input_sections()
       || this->must_sort_attached_input_sections()
-      || parameters->options().user_set_Map())
-    this->input_sections_.push_back(Input_section(object, shndx,
-                                                 shdr.get_sh_size(),
-                                                 addralign));
+      || parameters->options().user_set_Map()
+      || parameters->target().may_relax()
+      || parameters->options().section_ordering_file())
+    {
+      Input_section isecn(object, shndx, shdr.get_sh_size(), addralign);
+      if (parameters->options().section_ordering_file())
+        {
+          unsigned int section_order_index =
+            layout->find_section_order_index(std::string(secname));
+         if (section_order_index != 0)
+            {
+              isecn.set_section_order_index(section_order_index);
+              this->set_input_section_order_specified();
+            }
+        }
+      this->input_sections_.push_back(isecn);
+    }
 
   return aligned_offset_in_section;
 }
@@ -1898,6 +2138,29 @@ Output_section::add_output_section_data(Output_section_data* posd)
     }
 }
 
+// Add a relaxed input section.
+
+void
+Output_section::add_relaxed_input_section(Output_relaxed_input_section* poris)
+{
+  Input_section inp(poris);
+  this->add_output_section_data(&inp);
+  if (this->lookup_maps_->is_valid())
+    this->lookup_maps_->add_relaxed_input_section(poris->relobj(),
+                                                 poris->shndx(), poris);
+
+  // For a relaxed section, we use the current data size.  Linker scripts
+  // get all the input sections, including relaxed one from an output
+  // section and add them back to them same output section to compute the
+  // output section size.  If we do not account for sizes of relaxed input
+  // sections,  an output section would be incorrectly sized.
+  off_t offset_in_section = this->current_data_size_for_child();
+  off_t aligned_offset_in_section = align_address(offset_in_section,
+                                                 poris->addralign());
+  this->set_current_data_size_for_child(aligned_offset_in_section
+                                       + poris->current_data_size());
+}
+
 // Add arbitrary data to an output section by Input_section.
 
 void
@@ -1930,7 +2193,8 @@ Output_section::add_output_merge_section(Output_section_data* posd,
 bool
 Output_section::add_merge_input_section(Relobj* object, unsigned int shndx,
                                        uint64_t flags, uint64_t entsize,
-                                       uint64_t addralign)
+                                       uint64_t addralign,
+                                       bool keeps_input_sections)
 {
   bool is_string = (flags & elfcpp::SHF_STRINGS) != 0;
 
@@ -1939,43 +2203,272 @@ Output_section::add_merge_input_section(Relobj* object, unsigned int shndx,
   if (is_string && addralign > entsize)
     return false;
 
-  Input_section_list::iterator p;
-  for (p = this->input_sections_.begin();
-       p != this->input_sections_.end();
-       ++p)
-    if (p->is_merge_section(is_string, entsize, addralign))
+  // We cannot restore merged input section states.
+  gold_assert(this->checkpoint_ == NULL);
+
+  // Look up merge sections by required properties.
+  // Currently, we only invalidate the lookup maps in script processing
+  // and relaxation.  We should not have done either when we reach here.
+  // So we assume that the lookup maps are valid to simply code.
+  gold_assert(this->lookup_maps_->is_valid());
+  Merge_section_properties msp(is_string, entsize, addralign);
+  Output_merge_base* pomb = this->lookup_maps_->find_merge_section(msp);
+  bool is_new = false;
+  if (pomb != NULL)
+    {
+      gold_assert(pomb->is_string() == is_string
+                 && pomb->entsize() == entsize
+                 && pomb->addralign() == addralign);
+    }
+  else
+    {
+      // Create a new Output_merge_data or Output_merge_string_data.
+      if (!is_string)
+       pomb = new Output_merge_data(entsize, addralign);
+      else
+       {
+         switch (entsize)
+           {
+           case 1:
+             pomb = new Output_merge_string<char>(addralign);
+             break;
+           case 2:
+             pomb = new Output_merge_string<uint16_t>(addralign);
+             break;
+           case 4:
+             pomb = new Output_merge_string<uint32_t>(addralign);
+             break;
+           default:
+             return false;
+           }
+       }
+      // If we need to do script processing or relaxation, we need to keep
+      // the original input sections to rebuild the fast lookup maps.
+      if (keeps_input_sections)
+       pomb->set_keeps_input_sections();
+      is_new = true;
+    }
+
+  if (pomb->add_input_section(object, shndx))
+    {
+      // Add new merge section to this output section and link merge
+      // section properties to new merge section in map.
+      if (is_new)
+       {
+         this->add_output_merge_section(pomb, is_string, entsize);
+         this->lookup_maps_->add_merge_section(msp, pomb);
+       }
+
+      // Add input section to new merge section and link input section to new
+      // merge section in map.
+      this->lookup_maps_->add_merge_input_section(object, shndx, pomb);
+      return true;
+    }
+  else
+    {
+      // If add_input_section failed, delete new merge section to avoid
+      // exporting empty merge sections in Output_section::get_input_section.
+      if (is_new)
+       delete pomb;
+      return false;
+    }
+}
+
+// Build a relaxation map to speed up relaxation of existing input sections.
+// Look up to the first LIMIT elements in INPUT_SECTIONS.
+
+void
+Output_section::build_relaxation_map(
+  const Input_section_list& input_sections,
+  size_t limit,
+  Relaxation_map* relaxation_map) const
+{
+  for (size_t i = 0; i < limit; ++i)
+    {
+      const Input_section& is(input_sections[i]);
+      if (is.is_input_section() || is.is_relaxed_input_section())
+       {
+         Section_id sid(is.relobj(), is.shndx());
+         (*relaxation_map)[sid] = i;
+       }
+    }
+}
+
+// Convert regular input sections in INPUT_SECTIONS into relaxed input
+// sections in RELAXED_SECTIONS.  MAP is a prebuilt map from section id
+// indices of INPUT_SECTIONS.
+
+void
+Output_section::convert_input_sections_in_list_to_relaxed_sections(
+  const std::vector<Output_relaxed_input_section*>& relaxed_sections,
+  const Relaxation_map& map,
+  Input_section_list* input_sections)
+{
+  for (size_t i = 0; i < relaxed_sections.size(); ++i)
+    {
+      Output_relaxed_input_section* poris = relaxed_sections[i];
+      Section_id sid(poris->relobj(), poris->shndx());
+      Relaxation_map::const_iterator p = map.find(sid);
+      gold_assert(p != map.end());
+      gold_assert((*input_sections)[p->second].is_input_section());
+      (*input_sections)[p->second] = Input_section(poris);
+    }
+}
+  
+// Convert regular input sections into relaxed input sections. RELAXED_SECTIONS
+// is a vector of pointers to Output_relaxed_input_section or its derived
+// classes.  The relaxed sections must correspond to existing input sections.
+
+void
+Output_section::convert_input_sections_to_relaxed_sections(
+  const std::vector<Output_relaxed_input_section*>& relaxed_sections)
+{
+  gold_assert(parameters->target().may_relax());
+
+  // We want to make sure that restore_states does not undo the effect of
+  // this.  If there is no checkpoint active, just search the current
+  // input section list and replace the sections there.  If there is
+  // a checkpoint, also replace the sections there.
+  
+  // By default, we look at the whole list.
+  size_t limit = this->input_sections_.size();
+
+  if (this->checkpoint_ != NULL)
+    {
+      // Replace input sections with relaxed input section in the saved
+      // copy of the input section list.
+      if (this->checkpoint_->input_sections_saved())
+       {
+         Relaxation_map map;
+         this->build_relaxation_map(
+                   *(this->checkpoint_->input_sections()),
+                   this->checkpoint_->input_sections()->size(),
+                   &map);
+         this->convert_input_sections_in_list_to_relaxed_sections(
+                   relaxed_sections,
+                   map,
+                   this->checkpoint_->input_sections());
+       }
+      else
+       {
+         // We have not copied the input section list yet.  Instead, just
+         // look at the portion that would be saved.
+         limit = this->checkpoint_->input_sections_size();
+       }
+    }
+
+  // Convert input sections in input_section_list.
+  Relaxation_map map;
+  this->build_relaxation_map(this->input_sections_, limit, &map);
+  this->convert_input_sections_in_list_to_relaxed_sections(
+           relaxed_sections,
+           map,
+           &this->input_sections_);
+
+  // Update fast look-up map.
+  if (this->lookup_maps_->is_valid())
+    for (size_t i = 0; i < relaxed_sections.size(); ++i)
       {
-        p->add_input_section(object, shndx);
-        return true;
+       Output_relaxed_input_section* poris = relaxed_sections[i];
+       this->lookup_maps_->add_relaxed_input_section(poris->relobj(),
+                                                     poris->shndx(), poris);
       }
+}
+
+// Update the output section flags based on input section flags.
+
+void
+Output_section::update_flags_for_input_section(elfcpp::Elf_Xword flags)
+{
+  // If we created the section with SHF_ALLOC clear, we set the
+  // address.  If we are now setting the SHF_ALLOC flag, we need to
+  // undo that.
+  if ((this->flags_ & elfcpp::SHF_ALLOC) == 0
+      && (flags & elfcpp::SHF_ALLOC) != 0)
+    this->mark_address_invalid();
+
+  this->flags_ |= (flags
+                  & (elfcpp::SHF_WRITE
+                     | elfcpp::SHF_ALLOC
+                     | elfcpp::SHF_EXECINSTR));
+
+  if ((flags & elfcpp::SHF_MERGE) == 0)
+    this->flags_ &=~ elfcpp::SHF_MERGE;
+  else
+    {
+      if (this->current_data_size_for_child() == 0)
+       this->flags_ |= elfcpp::SHF_MERGE;
+    }
 
-  // We handle the actual constant merging in Output_merge_data or
-  // Output_merge_string_data.
-  Output_section_data* posd;
-  if (!is_string)
-    posd = new Output_merge_data(entsize, addralign);
+  if ((flags & elfcpp::SHF_STRINGS) == 0)
+    this->flags_ &=~ elfcpp::SHF_STRINGS;
   else
     {
-      switch (entsize)
+      if (this->current_data_size_for_child() == 0)
+       this->flags_ |= elfcpp::SHF_STRINGS;
+    }
+}
+
+// Find the merge section into which an input section with index SHNDX in
+// OBJECT has been added.  Return NULL if none found.
+
+Output_section_data*
+Output_section::find_merge_section(const Relobj* object,
+                                  unsigned int shndx) const
+{
+  if (!this->lookup_maps_->is_valid())
+    this->build_lookup_maps();
+  return this->lookup_maps_->find_merge_section(object, shndx);
+}
+
+// Build the lookup maps for merge and relaxed sections.  This is needs
+// to be declared as a const methods so that it is callable with a const
+// Output_section pointer.  The method only updates states of the maps.
+
+void
+Output_section::build_lookup_maps() const
+{
+  this->lookup_maps_->clear();
+  for (Input_section_list::const_iterator p = this->input_sections_.begin();
+       p != this->input_sections_.end();
+       ++p)
+    {
+      if (p->is_merge_section())
+       {
+         Output_merge_base* pomb = p->output_merge_base();
+         Merge_section_properties msp(pomb->is_string(), pomb->entsize(),
+                                      pomb->addralign());
+         this->lookup_maps_->add_merge_section(msp, pomb);
+         for (Output_merge_base::Input_sections::const_iterator is =
+                pomb->input_sections_begin();
+              is != pomb->input_sections_end();
+              ++is) 
+           {
+             const Const_section_id& csid = *is;
+           this->lookup_maps_->add_merge_input_section(csid.first,
+                                                       csid.second, pomb);
+           }
+           
+       }
+      else if (p->is_relaxed_input_section())
        {
-        case 1:
-         posd = new Output_merge_string<char>(addralign);
-         break;
-        case 2:
-         posd = new Output_merge_string<uint16_t>(addralign);
-         break;
-        case 4:
-         posd = new Output_merge_string<uint32_t>(addralign);
-         break;
-        default:
-         return false;
+         Output_relaxed_input_section* poris = p->relaxed_input_section();
+         this->lookup_maps_->add_relaxed_input_section(poris->relobj(),
+                                                       poris->shndx(), poris);
        }
     }
+}
 
-  this->add_output_merge_section(posd, is_string, entsize);
-  posd->add_input_section(object, shndx);
+// Find an relaxed input section corresponding to an input section
+// in OBJECT with index SHNDX.
 
-  return true;
+const Output_relaxed_input_section*
+Output_section::find_relaxed_input_section(const Relobj* object,
+                                          unsigned int shndx) const
+{
+  if (!this->lookup_maps_->is_valid())
+    this->build_lookup_maps();
+  return this->lookup_maps_->find_relaxed_input_section(object, shndx);
 }
 
 // Given an address OFFSET relative to the start of input section
@@ -1988,6 +2481,20 @@ Output_section::is_input_address_mapped(const Relobj* object,
                                        unsigned int shndx,
                                        off_t offset) const
 {
+  // Look at the Output_section_data_maps first.
+  const Output_section_data* posd = this->find_merge_section(object, shndx);
+  if (posd == NULL)
+    posd = this->find_relaxed_input_section(object, shndx);
+
+  if (posd != NULL)
+    {
+      section_offset_type output_offset;
+      bool found = posd->output_offset(object, shndx, offset, &output_offset);
+      gold_assert(found);   
+      return output_offset != -1;
+    }
+
+  // Fall back to the slow look-up.
   for (Input_section_list::const_iterator p = this->input_sections_.begin();
        p != this->input_sections_.end();
        ++p)
@@ -2012,9 +2519,23 @@ section_offset_type
 Output_section::output_offset(const Relobj* object, unsigned int shndx,
                              section_offset_type offset) const
 {
-  // This can only be called meaningfully when layout is complete.
-  gold_assert(Output_data::is_layout_complete());
-
+  // This can only be called meaningfully when we know the data size
+  // of this.
+  gold_assert(this->is_data_size_valid());
+
+  // Look at the Output_section_data_maps first.
+  const Output_section_data* posd = this->find_merge_section(object, shndx);
+  if (posd == NULL) 
+    posd = this->find_relaxed_input_section(object, shndx);
+  if (posd != NULL)
+    {
+      section_offset_type output_offset;
+      bool found = posd->output_offset(object, shndx, offset, &output_offset);
+      gold_assert(found);   
+      return output_offset;
+    }
+
+  // Fall back to the slow look-up.
   for (Input_section_list::const_iterator p = this->input_sections_.begin();
        p != this->input_sections_.end();
        ++p)
@@ -2034,6 +2555,20 @@ Output_section::output_address(const Relobj* object, unsigned int shndx,
                               off_t offset) const
 {
   uint64_t addr = this->address() + this->first_input_offset_;
+
+  // Look at the Output_section_data_maps first.
+  const Output_section_data* posd = this->find_merge_section(object, shndx);
+  if (posd == NULL) 
+    posd = this->find_relaxed_input_section(object, shndx);
+  if (posd != NULL && posd->is_address_valid())
+    {
+      section_offset_type output_offset;
+      bool found = posd->output_offset(object, shndx, offset, &output_offset);
+      gold_assert(found);
+      return posd->address() + output_offset;
+    }
+
+  // Fall back to the slow look-up.
   for (Input_section_list::const_iterator p = this->input_sections_.begin();
        p != this->input_sections_.end();
        ++p)
@@ -2065,6 +2600,9 @@ Output_section::find_starting_output_address(const Relobj* object,
                                             unsigned int shndx,
                                             uint64_t* paddr) const
 {
+  // FIXME: This becomes a bottle-neck if we have many relaxed sections.
+  // Looking up the merge section map does not always work as we sometimes
+  // find a merge section without its address set.
   uint64_t addr = this->address() + this->first_input_offset_;
   for (Input_section_list::const_iterator p = this->input_sections_.begin();
        p != this->input_sections_.end();
@@ -2101,7 +2639,8 @@ Output_section::set_final_data_size()
       return;
     }
 
-  if (this->must_sort_attached_input_sections())
+  if (this->must_sort_attached_input_sections()
+      || this->input_section_order_specified())
     this->sort_attached_input_sections();
 
   uint64_t address = this->address();
@@ -2125,11 +2664,33 @@ Output_section::set_final_data_size()
 void
 Output_section::do_reset_address_and_file_offset()
 {
+  // An unallocated section has no address.  Forcing this means that
+  // we don't need special treatment for symbols defined in debug
+  // sections.  We do the same in the constructor.  This does not
+  // apply to NOLOAD sections though.
+  if (((this->flags_ & elfcpp::SHF_ALLOC) == 0) && !this->is_noload_)
+     this->set_address(0);
+
   for (Input_section_list::iterator p = this->input_sections_.begin();
        p != this->input_sections_.end();
        ++p)
     p->reset_address_and_file_offset();
 }
+  
+// Return true if address and file offset have the values after reset.
+
+bool
+Output_section::do_address_and_file_offset_have_reset_values() const
+{
+  if (this->is_offset_valid())
+    return false;
+
+  // An unallocated section has address 0 after its construction or a reset.
+  if ((this->flags_ & elfcpp::SHF_ALLOC) == 0)
+    return this->is_address_valid() && this->address() == 0;
+  else
+    return !this->is_address_valid();
+}
 
 // Set the TLS offset.  Called only for SHT_TLS sections.
 
@@ -2156,17 +2717,22 @@ class Output_section::Input_section_sort_entry
   { }
 
   Input_section_sort_entry(const Input_section& input_section,
-                          unsigned int index)
+                          unsigned int index,
+                          bool must_sort_attached_input_sections)
     : input_section_(input_section), index_(index),
-      section_has_name_(input_section.is_input_section())
+      section_has_name_(input_section.is_input_section()
+                       || input_section.is_relaxed_input_section())
   {
-    if (this->section_has_name_)
+    if (this->section_has_name_
+        && must_sort_attached_input_sections)
       {
        // This is only called single-threaded from Layout::finalize,
        // so it is OK to lock.  Unfortunately we have no way to pass
        // in a Task token.
        const Task* dummy_task = reinterpret_cast<const Task*>(-1);
-       Object* obj = input_section.relobj();
+       Object* obj = (input_section.is_input_section()
+                      ? input_section.relobj()
+                      : input_section.relaxed_input_section()->relobj());
        Task_lock_obj<Object> tl(dummy_task, obj);
 
        // This is a slow operation, which should be cached in
@@ -2211,7 +2777,7 @@ class Output_section::Input_section_sort_entry
   has_priority() const
   {
     gold_assert(this->section_has_name_);
-    return this->section_name_.find('.', 1);
+    return this->section_name_.find('.', 1) != std::string::npos;
   }
 
   // Return true if this an input file whose base name matches
@@ -2235,6 +2801,23 @@ class Output_section::Input_section_sort_entry
     return memcmp(base_name + base_len - 2, ".o", 2) == 0;
   }
 
+  // Returns 1 if THIS should appear before S in section order, -1 if S
+  // appears before THIS and 0 if they are not comparable.
+  int
+  compare_section_ordering(const Input_section_sort_entry& s) const
+  {
+    unsigned int this_secn_index = this->input_section_.section_order_index();
+    unsigned int s_secn_index = s.input_section().section_order_index();
+    if (this_secn_index > 0 && s_secn_index > 0)
+      {
+        if (this_secn_index < s_secn_index)
+          return 1;
+        else if (this_secn_index > s_secn_index)
+          return -1;
+      }
+    return 0;
+  }
+
  private:
   // The Input_section we are sorting.
   Input_section input_section_;
@@ -2289,8 +2872,6 @@ Output_section::Input_section_sort_compare::operator()(
     }
 
   // A section with a priority follows a section without a priority.
-  // The GNU linker does this for all but .init_array sections; until
-  // further notice we'll assume that that is an mistake.
   bool s1_has_priority = s1.has_priority();
   bool s2_has_priority = s2.has_priority();
   if (s1_has_priority && !s2_has_priority)
@@ -2298,6 +2879,12 @@ Output_section::Input_section_sort_compare::operator()(
   if (!s1_has_priority && s2_has_priority)
     return true;
 
+  // Check if a section order exists for these sections through a section
+  // ordering file.  If sequence_num is 0, an order does not exist.
+  int sequence_num = s1.compare_section_ordering(s2);
+  if (sequence_num != 0)
+    return sequence_num == 1;
+
   // Otherwise we sort by name.
   int compare = s1.section_name().compare(s2.section_name());
   if (compare != 0)
@@ -2307,6 +2894,67 @@ Output_section::Input_section_sort_compare::operator()(
   return s1.index() < s2.index();
 }
 
+// Return true if S1 should come before S2 in an .init_array or .fini_array
+// output section.
+
+bool
+Output_section::Input_section_sort_init_fini_compare::operator()(
+    const Output_section::Input_section_sort_entry& s1,
+    const Output_section::Input_section_sort_entry& s2) const
+{
+  // We sort all the sections with no names to the end.
+  if (!s1.section_has_name() || !s2.section_has_name())
+    {
+      if (s1.section_has_name())
+       return true;
+      if (s2.section_has_name())
+       return false;
+      return s1.index() < s2.index();
+    }
+
+  // A section without a priority follows a section with a priority.
+  // This is the reverse of .ctors and .dtors sections.
+  bool s1_has_priority = s1.has_priority();
+  bool s2_has_priority = s2.has_priority();
+  if (s1_has_priority && !s2_has_priority)
+    return true;
+  if (!s1_has_priority && s2_has_priority)
+    return false;
+
+  // Check if a section order exists for these sections through a section
+  // ordering file.  If sequence_num is 0, an order does not exist.
+  int sequence_num = s1.compare_section_ordering(s2);
+  if (sequence_num != 0)
+    return sequence_num == 1;
+
+  // Otherwise we sort by name.
+  int compare = s1.section_name().compare(s2.section_name());
+  if (compare != 0)
+    return compare < 0;
+
+  // Otherwise we keep the input order.
+  return s1.index() < s2.index();
+}
+
+// Return true if S1 should come before S2.  Sections that do not match
+// any pattern in the section ordering file are placed ahead of the sections
+// that match some pattern.
+
+bool
+Output_section::Input_section_sort_section_order_index_compare::operator()(
+    const Output_section::Input_section_sort_entry& s1,
+    const Output_section::Input_section_sort_entry& s2) const
+{
+  unsigned int s1_secn_index = s1.input_section().section_order_index();
+  unsigned int s2_secn_index = s2.input_section().section_order_index();
+
+  // Keep input order if section ordering cannot determine order.
+  if (s1_secn_index == s2_secn_index)
+    return s1.index() < s2.index();
+  
+  return s1_secn_index < s2_secn_index;
+}
+
 // Sort the input sections attached to an output section.
 
 void
@@ -2315,6 +2963,10 @@ Output_section::sort_attached_input_sections()
   if (this->attached_input_sections_are_sorted_)
     return;
 
+  if (this->checkpoint_ != NULL
+      && !this->checkpoint_->input_sections_saved())
+    this->checkpoint_->save_input_sections();
+
   // The only thing we know about an input section is the object and
   // the section index.  We need the section name.  Recomputing this
   // is slow but this is an unusual case.  If this becomes a speed
@@ -2328,10 +2980,27 @@ Output_section::sort_attached_input_sections()
   for (Input_section_list::iterator p = this->input_sections_.begin();
        p != this->input_sections_.end();
        ++p, ++i)
-    sort_list.push_back(Input_section_sort_entry(*p, i));
+      sort_list.push_back(Input_section_sort_entry(*p, i,
+                            this->must_sort_attached_input_sections()));
 
   // Sort the input sections.
-  std::sort(sort_list.begin(), sort_list.end(), Input_section_sort_compare());
+  if (this->must_sort_attached_input_sections())
+    {
+      if (this->type() == elfcpp::SHT_PREINIT_ARRAY
+          || this->type() == elfcpp::SHT_INIT_ARRAY
+          || this->type() == elfcpp::SHT_FINI_ARRAY)
+        std::sort(sort_list.begin(), sort_list.end(),
+                 Input_section_sort_init_fini_compare());
+      else
+        std::sort(sort_list.begin(), sort_list.end(),
+                 Input_section_sort_compare());
+    }
+  else
+    {
+      gold_assert(parameters->options().section_ordering_file());
+      std::sort(sort_list.begin(), sort_list.end(),
+               Input_section_sort_section_order_index_compare());
+    }
 
   // Copy the sorted input sections back to our list.
   this->input_sections_.clear();
@@ -2339,6 +3008,7 @@ Output_section::sort_attached_input_sections()
        p != sort_list.end();
        ++p)
     this->input_sections_.push_back(p->input_section());
+  sort_list.clear();
 
   // Remember that we sorted the input sections, since we might get
   // called again.
@@ -2400,6 +3070,9 @@ Output_section::do_write(Output_file* of)
 {
   gold_assert(!this->requires_postprocessing());
 
+  // If the target performs relaxation, we delay filler generation until now.
+  gold_assert(!this->generate_code_fills_at_write_ || this->fills_.empty());
+
   off_t output_section_file_offset = this->offset();
   for (Fill_list::iterator p = this->fills_.begin();
        p != this->fills_.end();
@@ -2410,10 +3083,22 @@ Output_section::do_write(Output_file* of)
                fill_data.data(), fill_data.size());
     }
 
+  off_t off = this->offset() + this->first_input_offset_;
   for (Input_section_list::iterator p = this->input_sections_.begin();
        p != this->input_sections_.end();
        ++p)
-    p->write(of);
+    {
+      off_t aligned_off = align_address(off, p->addralign());
+      if (this->generate_code_fills_at_write_ && (off != aligned_off))
+       {
+         size_t fill_len = aligned_off - off;
+         std::string fill_data(parameters->target().code_fill(fill_len));
+         of->write(off, fill_data.data(), fill_data.size());
+       }
+
+      p->write(of);
+      off = aligned_off + p->data_size();
+    }
 }
 
 // If a section requires postprocessing, create the buffer to use.
@@ -2454,6 +3139,9 @@ Output_section::write_to_postprocessing_buffer()
 {
   gold_assert(this->requires_postprocessing());
 
+  // If the target performs relaxation, we delay filler generation until now.
+  gold_assert(!this->generate_code_fills_at_write_ || this->fills_.empty());
+
   unsigned char* buffer = this->postprocessing_buffer();
   for (Fill_list::iterator p = this->fills_.begin();
        p != this->fills_.end();
@@ -2469,9 +3157,16 @@ Output_section::write_to_postprocessing_buffer()
        p != this->input_sections_.end();
        ++p)
     {
-      off = align_address(off, p->addralign());
-      p->write_to_buffer(buffer + off);
-      off += p->data_size();
+      off_t aligned_off = align_address(off, p->addralign());
+      if (this->generate_code_fills_at_write_ && (off != aligned_off))
+       {
+         size_t fill_len = aligned_off - off;
+         std::string fill_data(parameters->target().code_fill(fill_len));
+         memcpy(buffer + off, fill_data.data(), fill_data.size());
+       }
+
+      p->write_to_buffer(buffer + aligned_off);
+      off = aligned_off + p->data_size();
     }
 }
 
@@ -2489,8 +3184,15 @@ uint64_t
 Output_section::get_input_sections(
     uint64_t address,
     const std::string& fill,
-    std::list<std::pair<Relobj*, unsigned int> >* input_sections)
+    std::list<Input_section>* input_sections)
 {
+  if (this->checkpoint_ != NULL
+      && !this->checkpoint_->input_sections_saved())
+    this->checkpoint_->save_input_sections();
+
+  // Invalidate fast look-up maps.
+  this->lookup_maps_->invalidate();
+
   uint64_t orig_address = address;
 
   address = align_address(address, this->addralign());
@@ -2500,8 +3202,10 @@ Output_section::get_input_sections(
        p != this->input_sections_.end();
        ++p)
     {
-      if (p->is_input_section())
-       input_sections->push_back(std::make_pair(p->relobj(), p->shndx()));
+      if (p->is_input_section()
+         || p->is_relaxed_input_section()
+         || p->is_merge_section())
+       input_sections->push_back(*p);
       else
        {
          uint64_t aligned_address = align_address(address, p->addralign());
@@ -2536,14 +3240,16 @@ Output_section::get_input_sections(
   return data_size;
 }
 
-// Add an input section from a script.
+// Add a script input section.  SIS is an Output_section::Input_section,
+// which can be either a plain input section or a special input section like
+// a relaxed input section.  For a special input section, its size must be
+// finalized.
 
 void
-Output_section::add_input_section_for_script(Relobj* object,
-                                            unsigned int shndx,
-                                            off_t data_size,
-                                            uint64_t addralign)
+Output_section::add_script_input_section(const Input_section& sis)
 {
+  uint64_t data_size = sis.data_size();
+  uint64_t addralign = sis.addralign();
   if (addralign > this->addralign_)
     this->addralign_ = addralign;
 
@@ -2554,8 +3260,116 @@ Output_section::add_input_section_for_script(Relobj* object,
   this->set_current_data_size_for_child(aligned_offset_in_section
                                        + data_size);
 
-  this->input_sections_.push_back(Input_section(object, shndx,
-                                               data_size, addralign));
+  this->input_sections_.push_back(sis);
+
+  // Update fast lookup maps if necessary. 
+  if (this->lookup_maps_->is_valid())
+    {
+      if (sis.is_merge_section())
+       {
+         Output_merge_base* pomb = sis.output_merge_base();
+         Merge_section_properties msp(pomb->is_string(), pomb->entsize(),
+                                      pomb->addralign());
+         this->lookup_maps_->add_merge_section(msp, pomb);
+         for (Output_merge_base::Input_sections::const_iterator p =
+                pomb->input_sections_begin();
+              p != pomb->input_sections_end();
+              ++p)
+           this->lookup_maps_->add_merge_input_section(p->first, p->second,
+                                                       pomb);
+       }
+      else if (sis.is_relaxed_input_section())
+       {
+         Output_relaxed_input_section* poris = sis.relaxed_input_section();
+         this->lookup_maps_->add_relaxed_input_section(poris->relobj(),
+                                                       poris->shndx(), poris);
+       }
+    }
+}
+
+// Save states for relaxation.
+
+void
+Output_section::save_states()
+{
+  gold_assert(this->checkpoint_ == NULL);
+  Checkpoint_output_section* checkpoint =
+    new Checkpoint_output_section(this->addralign_, this->flags_,
+                                 this->input_sections_,
+                                 this->first_input_offset_,
+                                 this->attached_input_sections_are_sorted_);
+  this->checkpoint_ = checkpoint;
+  gold_assert(this->fills_.empty());
+}
+
+void
+Output_section::discard_states()
+{
+  gold_assert(this->checkpoint_ != NULL);
+  delete this->checkpoint_;
+  this->checkpoint_ = NULL;
+  gold_assert(this->fills_.empty());
+
+  // Simply invalidate the fast lookup maps since we do not keep
+  // track of them.
+  this->lookup_maps_->invalidate();
+}
+
+void
+Output_section::restore_states()
+{
+  gold_assert(this->checkpoint_ != NULL);
+  Checkpoint_output_section* checkpoint = this->checkpoint_;
+
+  this->addralign_ = checkpoint->addralign();
+  this->flags_ = checkpoint->flags();
+  this->first_input_offset_ = checkpoint->first_input_offset();
+
+  if (!checkpoint->input_sections_saved())
+    {
+      // If we have not copied the input sections, just resize it.
+      size_t old_size = checkpoint->input_sections_size();
+      gold_assert(this->input_sections_.size() >= old_size);
+      this->input_sections_.resize(old_size);
+    }
+  else
+    {
+      // We need to copy the whole list.  This is not efficient for
+      // extremely large output with hundreads of thousands of input
+      // objects.  We may need to re-think how we should pass sections
+      // to scripts.
+      this->input_sections_ = *checkpoint->input_sections();
+    }
+
+  this->attached_input_sections_are_sorted_ =
+    checkpoint->attached_input_sections_are_sorted();
+
+  // Simply invalidate the fast lookup maps since we do not keep
+  // track of them.
+  this->lookup_maps_->invalidate();
+}
+
+// Update the section offsets of input sections in this.  This is required if
+// relaxation causes some input sections to change sizes.
+
+void
+Output_section::adjust_section_offsets()
+{
+  if (!this->section_offsets_need_adjustment_)
+    return;
+
+  off_t off = 0;
+  for (Input_section_list::iterator p = this->input_sections_.begin();
+       p != this->input_sections_.end();
+       ++p)
+    {
+      off = align_address(off, p->addralign());
+      if (p->is_input_section())
+       p->relobj()->set_section_offset(p->shndx(), off);
+      off += p->data_size();
+    }
+
+  this->section_offsets_need_adjustment_ = false;
 }
 
 // Print to the map file.
@@ -2598,21 +3412,28 @@ Output_segment::Output_segment(elfcpp::Elf_Word type, elfcpp::Elf_Word flags)
     type_(type),
     flags_(flags),
     is_max_align_known_(false),
-    are_addresses_set_(false)
+    are_addresses_set_(false),
+    is_large_data_segment_(false)
 {
+  // The ELF ABI specifies that a PT_TLS segment always has PF_R as
+  // the flags.
+  if (type == elfcpp::PT_TLS)
+    this->flags_ = elfcpp::PF_R;
 }
 
 // Add an Output_section to an Output_segment.
 
 void
 Output_segment::add_output_section(Output_section* os,
-                                  elfcpp::Elf_Word seg_flags)
+                                  elfcpp::Elf_Word seg_flags,
+                                  bool do_sort)
 {
   gold_assert((os->flags() & elfcpp::SHF_ALLOC) != 0);
   gold_assert(!this->is_max_align_known_);
+  gold_assert(os->is_large_data_section() == this->is_large_data_segment());
+  gold_assert(this->type() == elfcpp::PT_LOAD || !do_sort);
 
-  // Update the segment flags.
-  this->flags_ |= seg_flags;
+  this->update_flags_for_output_section(seg_flags);
 
   Output_segment::Output_data_list* pdl;
   if (os->type() == elfcpp::SHT_NOBITS)
@@ -2620,19 +3441,12 @@ Output_segment::add_output_section(Output_section* os,
   else
     pdl = &this->output_data_;
 
-  // So that PT_NOTE segments will work correctly, we need to ensure
-  // that all SHT_NOTE sections are adjacent.  This will normally
-  // happen automatically, because all the SHT_NOTE input sections
-  // will wind up in the same output section.  However, it is possible
-  // for multiple SHT_NOTE input sections to have different section
-  // flags, and thus be in different output sections, but for the
-  // different section flags to map into the same segment flags and
-  // thus the same output segment.
-
   // Note that while there may be many input sections in an output
   // section, there are normally only a few output sections in an
-  // output segment.  This loop is expected to be fast.
+  // output segment.  The loops below are expected to be fast.
 
+  // So that PT_NOTE segments will work correctly, we need to ensure
+  // that all SHT_NOTE sections are adjacent.
   if (os->type() == elfcpp::SHT_NOTE && !pdl->empty())
     {
       Output_segment::Output_data_list::iterator p = pdl->end();
@@ -2654,69 +3468,225 @@ Output_segment::add_output_section(Output_section* os,
   // case: we group the SHF_TLS/SHT_NOBITS sections right after the
   // SHF_TLS/SHT_PROGBITS sections.  This lets us set up PT_TLS
   // correctly.  SHF_TLS sections get added to both a PT_LOAD segment
-  // and the PT_TLS segment -- we do this grouping only for the
-  // PT_LOAD segment.
+  // and the PT_TLS segment; we do this grouping only for the PT_LOAD
+  // segment.
   if (this->type_ != elfcpp::PT_TLS
       && (os->flags() & elfcpp::SHF_TLS) != 0)
     {
       pdl = &this->output_data_;
-      bool nobits = os->type() == elfcpp::SHT_NOBITS;
-      bool sawtls = false;
-      Output_segment::Output_data_list::iterator p = pdl->end();
-      do
+      if (!pdl->empty())
        {
-         --p;
-         bool insert;
-         if ((*p)->is_section_flag_set(elfcpp::SHF_TLS))
+         bool nobits = os->type() == elfcpp::SHT_NOBITS;
+         bool sawtls = false;
+         Output_segment::Output_data_list::iterator p = pdl->end();
+         gold_assert(p != pdl->begin());
+         do
            {
-             sawtls = true;
-             // Put a NOBITS section after the first TLS section.
-             // Put a PROGBITS section after the first TLS/PROGBITS
-             // section.
-             insert = nobits || !(*p)->is_section_type(elfcpp::SHT_NOBITS);
+             --p;
+             bool insert;
+             if ((*p)->is_section_flag_set(elfcpp::SHF_TLS))
+               {
+                 sawtls = true;
+                 // Put a NOBITS section after the first TLS section.
+                 // Put a PROGBITS section after the first
+                 // TLS/PROGBITS section.
+                 insert = nobits || !(*p)->is_section_type(elfcpp::SHT_NOBITS);
+               }
+             else
+               {
+                 // If we've gone past the TLS sections, but we've
+                 // seen a TLS section, then we need to insert this
+                 // section now.
+                 insert = sawtls;
+               }
+
+             if (insert)
+               {
+                 ++p;
+                 pdl->insert(p, os);
+                 return;
+               }
            }
-         else
+         while (p != pdl->begin());
+       }
+
+      // There are no TLS sections yet; put this one at the requested
+      // location in the section list.
+    }
+
+  if (do_sort)
+    {
+      // For the PT_GNU_RELRO segment, we need to group relro
+      // sections, and we need to put them before any non-relro
+      // sections.  Any relro local sections go before relro non-local
+      // sections.  One section may be marked as the last relro
+      // section.
+      if (os->is_relro())
+       {
+         gold_assert(pdl == &this->output_data_);
+         Output_segment::Output_data_list::iterator p;
+         for (p = pdl->begin(); p != pdl->end(); ++p)
            {
-             // If we've gone past the TLS sections, but we've seen a
-             // TLS section, then we need to insert this section now.
-             insert = sawtls;
+             if (!(*p)->is_section())
+               break;
+
+             Output_section* pos = (*p)->output_section();
+             if (!pos->is_relro()
+                 || (os->is_relro_local() && !pos->is_relro_local())
+                 || (!os->is_last_relro() && pos->is_last_relro()))
+               break;
            }
 
-         if (insert)
+         pdl->insert(p, os);
+         return;
+       }
+
+      // One section may be marked as the first section which follows
+      // the relro sections.
+      if (os->is_first_non_relro())
+       {
+         gold_assert(pdl == &this->output_data_);
+         Output_segment::Output_data_list::iterator p;
+         for (p = pdl->begin(); p != pdl->end(); ++p)
+           {
+             if (!(*p)->is_section())
+               break;
+
+             Output_section* pos = (*p)->output_section();
+             if (!pos->is_relro())
+               break;
+           }
+
+         pdl->insert(p, os);
+         return;
+       }
+    }
+
+  // Small data sections go at the end of the list of data sections.
+  // If OS is not small, and there are small sections, we have to
+  // insert it before the first small section.
+  if (os->type() != elfcpp::SHT_NOBITS
+      && !os->is_small_section()
+      && !pdl->empty()
+      && pdl->back()->is_section()
+      && pdl->back()->output_section()->is_small_section())
+    {
+      for (Output_segment::Output_data_list::iterator p = pdl->begin();
+          p != pdl->end();
+          ++p)
+       {
+         if ((*p)->is_section()
+             && (*p)->output_section()->is_small_section())
            {
-             ++p;
              pdl->insert(p, os);
              return;
            }
        }
-      while (p != pdl->begin());
+      gold_unreachable();
+    }
 
-      // There are no TLS sections yet; put this one at the requested
-      // location in the section list.
+  // A small BSS section goes at the start of the BSS sections, after
+  // other small BSS sections.
+  if (os->type() == elfcpp::SHT_NOBITS && os->is_small_section())
+    {
+      for (Output_segment::Output_data_list::iterator p = pdl->begin();
+          p != pdl->end();
+          ++p)
+       {
+         if (!(*p)->is_section()
+             || !(*p)->output_section()->is_small_section())
+           {
+             pdl->insert(p, os);
+             return;
+           }
+       }
     }
 
-  // For the PT_GNU_RELRO segment, we need to group relro sections,
-  // and we need to put them before any non-relro sections.  Also,
-  // relro local sections go before relro non-local sections.
-  if (parameters->options().relro() && os->is_relro())
+  // A large BSS section goes at the end of the BSS sections, which
+  // means that one that is not large must come before the first large
+  // one.
+  if (os->type() == elfcpp::SHT_NOBITS
+      && !os->is_large_section()
+      && !pdl->empty()
+      && pdl->back()->is_section()
+      && pdl->back()->output_section()->is_large_section())
     {
-      gold_assert(pdl == &this->output_data_);
-      Output_segment::Output_data_list::iterator p;
-      for (p = pdl->begin(); p != pdl->end(); ++p)
+      for (Output_segment::Output_data_list::iterator p = pdl->begin();
+          p != pdl->end();
+          ++p)
        {
-         if (!(*p)->is_section())
-           break;
+         if ((*p)->is_section()
+             && (*p)->output_section()->is_large_section())
+           {
+             pdl->insert(p, os);
+             return;
+           }
+       }
+      gold_unreachable();
+    }
 
-         Output_section* pos = (*p)->output_section();
-         if (!pos->is_relro()
-             || (os->is_relro_local() && !pos->is_relro_local()))
-           break;
+  // We do some further output section sorting in order to make the
+  // generated program run more efficiently.  We should only do this
+  // when not using a linker script, so it is controled by the DO_SORT
+  // parameter.
+  if (do_sort)
+    {
+      // FreeBSD requires the .interp section to be in the first page
+      // of the executable.  That is a more efficient location anyhow
+      // for any OS, since it means that the kernel will have the data
+      // handy after it reads the program headers.
+      if (os->is_interp() && !pdl->empty())
+       {
+         pdl->insert(pdl->begin(), os);
+         return;
        }
 
-      pdl->insert(p, os);
-      return;
+      // Put loadable non-writable notes immediately after the .interp
+      // sections, so that the PT_NOTE segment is on the first page of
+      // the executable.
+      if (os->type() == elfcpp::SHT_NOTE
+         && (os->flags() & elfcpp::SHF_WRITE) == 0
+         && !pdl->empty())
+       {
+         Output_segment::Output_data_list::iterator p = pdl->begin();
+         if ((*p)->is_section() && (*p)->output_section()->is_interp())
+           ++p;
+         pdl->insert(p, os);
+         return;
+       }
+
+      // If this section is used by the dynamic linker, and it is not
+      // writable, then put it first, after the .interp section and
+      // any loadable notes.  This makes it more likely that the
+      // dynamic linker will have to read less data from the disk.
+      if (os->is_dynamic_linker_section()
+         && !pdl->empty()
+         && (os->flags() & elfcpp::SHF_WRITE) == 0)
+       {
+         bool is_reloc = (os->type() == elfcpp::SHT_REL
+                          || os->type() == elfcpp::SHT_RELA);
+         Output_segment::Output_data_list::iterator p = pdl->begin();
+         while (p != pdl->end()
+                && (*p)->is_section()
+                && ((*p)->output_section()->is_dynamic_linker_section()
+                    || (*p)->output_section()->type() == elfcpp::SHT_NOTE))
+           {
+             // Put reloc sections after the other ones.  Putting the
+             // dynamic reloc sections first confuses BFD, notably
+             // objcopy and strip.
+             if (!is_reloc
+                 && ((*p)->output_section()->type() == elfcpp::SHT_REL
+                     || (*p)->output_section()->type() == elfcpp::SHT_RELA))
+               break;
+             ++p;
+           }
+         pdl->insert(p, os);
+         return;
+       }
     }
 
+  // If there were no constraints on the output section, just add it
+  // to the end of the list.
   pdl->push_back(os);
 }
 
@@ -2741,8 +3711,8 @@ Output_segment::remove_output_section(Output_section* os)
   gold_unreachable();
 }
 
-// Add an Output_data (which is not an Output_section) to the start of
-// a segment.
+// Add an Output_data (which need not be an Output_section) to the
+// start of a segment.
 
 void
 Output_segment::add_initial_output_data(Output_data* od)
@@ -2778,19 +3748,6 @@ Output_segment::maximum_alignment()
       if (addralign > this->max_align_)
        this->max_align_ = addralign;
 
-      // If -z relro is in effect, and the first section in this
-      // segment is a relro section, then the segment must be aligned
-      // to at least the common page size.  This ensures that the
-      // PT_GNU_RELRO segment will start at a page boundary.
-      if (this->type_ == elfcpp::PT_LOAD
-         && parameters->options().relro()
-         && this->is_first_section_relro())
-       {
-         addralign = parameters->target().common_pagesize();
-         if (addralign > this->max_align_)
-           this->max_align_ = addralign;
-       }
-
       this->is_max_align_known_ = true;
     }
 
@@ -2844,11 +3801,57 @@ Output_segment::dynamic_reloc_count_list(const Output_data_list* pdl) const
 
 uint64_t
 Output_segment::set_section_addresses(const Layout* layout, bool reset,
-                                      uint64_t addr, off_t* poff,
+                                      uint64_t addr,
+                                     unsigned int increase_relro,
+                                     off_t* poff,
                                      unsigned int* pshndx)
 {
   gold_assert(this->type_ == elfcpp::PT_LOAD);
 
+  off_t orig_off = *poff;
+
+  // If we have relro sections, we need to pad forward now so that the
+  // relro sections plus INCREASE_RELRO end on a common page boundary.
+  if (parameters->options().relro()
+      && this->is_first_section_relro()
+      && (!this->are_addresses_set_ || reset))
+    {
+      uint64_t relro_size = 0;
+      off_t off = *poff;
+      for (Output_data_list::iterator p = this->output_data_.begin();
+          p != this->output_data_.end();
+          ++p)
+       {
+         if (!(*p)->is_section())
+           break;
+         Output_section* pos = (*p)->output_section();
+         if (!pos->is_relro())
+           break;
+         gold_assert(!(*p)->is_section_flag_set(elfcpp::SHF_TLS));
+         if ((*p)->is_address_valid())
+           relro_size += (*p)->data_size();
+         else
+           {
+             // FIXME: This could be faster.
+             (*p)->set_address_and_file_offset(addr + relro_size,
+                                               off + relro_size);
+             relro_size += (*p)->data_size();
+             (*p)->reset_address_and_file_offset();
+           }
+       }
+      relro_size += increase_relro;
+
+      uint64_t page_align = parameters->target().common_pagesize();
+
+      // Align to offset N such that (N + RELRO_SIZE) % PAGE_ALIGN == 0.
+      uint64_t desired_align = page_align - (relro_size % page_align);
+      if (desired_align < *poff % page_align)
+       *poff += page_align - *poff % page_align;
+      *poff += desired_align - *poff % page_align;
+      addr += *poff - orig_off;
+      orig_off = *poff;
+    }
+
   if (!reset && this->are_addresses_set_)
     {
       gold_assert(this->paddr_ == addr);
@@ -2863,15 +3866,10 @@ Output_segment::set_section_addresses(const Layout* layout, bool reset,
 
   bool in_tls = false;
 
-  bool in_relro = (parameters->options().relro()
-                  && this->is_first_section_relro());
-
-  off_t orig_off = *poff;
   this->offset_ = orig_off;
 
   addr = this->set_section_list_addresses(layout, reset, &this->output_data_,
-                                         addr, poff, pshndx, &in_tls,
-                                         &in_relro);
+                                         addr, poff, pshndx, &in_tls);
   this->filesz_ = *poff - orig_off;
 
   off_t off = *poff;
@@ -2879,7 +3877,7 @@ Output_segment::set_section_addresses(const Layout* layout, bool reset,
   uint64_t ret = this->set_section_list_addresses(layout, reset,
                                                   &this->output_bss_,
                                                  addr, poff, pshndx,
-                                                  &in_tls, &in_relro);
+                                                  &in_tls);
 
   // If the last section was a TLS section, align upward to the
   // alignment of the TLS segment, so that the overall size of the TLS
@@ -2890,14 +3888,6 @@ Output_segment::set_section_addresses(const Layout* layout, bool reset,
       *poff = align_address(*poff, segment_align);
     }
 
-  // If all the sections were relro sections, align upward to the
-  // common page size.
-  if (in_relro)
-    {
-      uint64_t page_align = parameters->target().common_pagesize();
-      *poff = align_address(*poff, page_align);
-    }
-
   this->memsz_ = *poff - orig_off;
 
   // Ignore the file offset adjustments made by the BSS Output_data
@@ -2915,7 +3905,7 @@ Output_segment::set_section_list_addresses(const Layout* layout, bool reset,
                                            Output_data_list* pdl,
                                           uint64_t addr, off_t* poff,
                                           unsigned int* pshndx,
-                                           bool* in_tls, bool* in_relro)
+                                           bool* in_tls)
 {
   off_t startoff = *poff;
 
@@ -2966,19 +3956,6 @@ Output_segment::set_section_list_addresses(const Layout* layout, bool reset,
                 }
             }
 
-         // If this is a non-relro section after a relro section,
-         // align it to a common page boundary so that the dynamic
-         // linker has a page to mark as read-only.
-         if (*in_relro
-             && (!(*p)->is_section()
-                 || !(*p)->output_section()->is_relro()))
-           {
-             uint64_t page_align = parameters->target().common_pagesize();
-             if (page_align > align)
-               align = page_align;
-             *in_relro = false;
-           }
-
          off = align_address(off, align);
          (*p)->set_address_and_file_offset(addr + (off - startoff), off);
        }
@@ -2986,8 +3963,31 @@ Output_segment::set_section_list_addresses(const Layout* layout, bool reset,
        {
          // The script may have inserted a skip forward, but it
          // better not have moved backward.
-         gold_assert((*p)->address() >= addr + (off - startoff));
-         off += (*p)->address() - (addr + (off - startoff));
+         if ((*p)->address() >= addr + (off - startoff))
+           off += (*p)->address() - (addr + (off - startoff));
+         else
+           {
+             if (!layout->script_options()->saw_sections_clause())
+               gold_unreachable();
+             else
+               {
+                 Output_section* os = (*p)->output_section();
+
+                 // Cast to unsigned long long to avoid format warnings.
+                 unsigned long long previous_dot =
+                   static_cast<unsigned long long>(addr + (off - startoff));
+                 unsigned long long dot =
+                   static_cast<unsigned long long>((*p)->address());
+
+                 if (os == NULL)
+                   gold_error(_("dot moves backward in linker script "
+                                "from 0x%llx to 0x%llx"), previous_dot, dot);
+                 else
+                   gold_error(_("address of section '%s' moves backward "
+                                "from 0x%llx to 0x%llx"),
+                              os->name(), previous_dot, dot);
+               }
+           }
          (*p)->set_file_offset(off);
          (*p)->finalize_data_size();
        }
@@ -3011,10 +4011,10 @@ Output_segment::set_section_list_addresses(const Layout* layout, bool reset,
 }
 
 // For a non-PT_LOAD segment, set the offset from the sections, if
-// any.
+// any.  Add INCREASE to the file size and the memory size.
 
 void
-Output_segment::set_offset()
+Output_segment::set_offset(unsigned int increase)
 {
   gold_assert(this->type_ != elfcpp::PT_LOAD);
 
@@ -3022,6 +4022,7 @@ Output_segment::set_offset()
 
   if (this->output_data_.empty() && this->output_bss_.empty())
     {
+      gold_assert(increase == 0);
       this->vaddr_ = 0;
       this->paddr_ = 0;
       this->are_addresses_set_ = true;
@@ -3063,6 +4064,9 @@ Output_segment::set_offset()
                  + last->data_size()
                  - this->vaddr_);
 
+  this->filesz_ += increase;
+  this->memsz_ += increase;
+
   // If this is a TLS segment, align the memory size.  The code in
   // set_section_list ensures that the section after the TLS segment
   // is aligned to give us room.
@@ -3072,16 +4076,6 @@ Output_segment::set_offset()
       gold_assert(this->vaddr_ == align_address(this->vaddr_, segment_align));
       this->memsz_ = align_address(this->memsz_, segment_align);
     }
-
-  // If this is a RELRO segment, align the memory size.  The code in
-  // set_section_list ensures that the section after the RELRO segment
-  // is aligned to give us room.
-  if (this->type_ == elfcpp::PT_GNU_RELRO)
-    {
-      uint64_t page_align = parameters->target().common_pagesize();
-      gold_assert(this->vaddr_ == align_address(this->vaddr_, page_align));
-      this->memsz_ = align_address(this->memsz_, page_align);
-    }
 }
 
 // Set the TLS offsets of the sections in the PT_TLS segment.
@@ -3297,6 +4291,42 @@ Output_file::Output_file(const char* name)
 {
 }
 
+// Try to open an existing file.  Returns false if the file doesn't
+// exist, has a size of 0 or can't be mmapped.
+
+bool
+Output_file::open_for_modification()
+{
+  // The name "-" means "stdout".
+  if (strcmp(this->name_, "-") == 0)
+    return false;
+
+  // Don't bother opening files with a size of zero.
+  struct stat s;
+  if (::stat(this->name_, &s) != 0 || s.st_size == 0)
+    return false;
+
+  int o = open_descriptor(-1, this->name_, O_RDWR, 0);
+  if (o < 0)
+    gold_fatal(_("%s: open: %s"), this->name_, strerror(errno));
+  this->o_ = o;
+  this->file_size_ = s.st_size;
+
+  // If the file can't be mmapped, copying the content to an anonymous
+  // map will probably negate the performance benefits of incremental
+  // linking.  This could be helped by using views and loading only
+  // the necessary parts, but this is not supported as of now.
+  if (!this->map_no_anonymous())
+    {
+      release_descriptor(o, true);
+      this->o_ = -1;
+      this->file_size_ = 0;
+      return false;
+    }
+
+  return true;
+}
+
 // Open the output file.
 
 void
@@ -3325,8 +4355,22 @@ Output_file::open(off_t file_size)
       else
        {
          struct stat s;
-         if (::stat(this->name_, &s) == 0 && s.st_size != 0)
-           unlink_if_ordinary(this->name_);
+         if (::stat(this->name_, &s) == 0
+             && (S_ISREG (s.st_mode) || S_ISLNK (s.st_mode)))
+           {
+             if (s.st_size != 0)
+               ::unlink(this->name_);
+             else if (!parameters->options().relocatable())
+               {
+                 // If we don't unlink the existing file, add execute
+                 // permission where read permissions already exist
+                 // and where the umask permits.
+                 int mask = ::umask(0);
+                 ::umask(mask);
+                 s.st_mode |= (s.st_mode & 0444) >> 2;
+                 ::chmod(this->name_, s.st_mode & ~mask);
+               }
+           }
 
          int mode = parameters->options().relocatable() ? 0666 : 0777;
          int o = open_descriptor(-1, this->name_, O_RDWR | O_CREAT | O_TRUNC,
@@ -3361,14 +4405,32 @@ Output_file::resize(off_t file_size)
     {
       this->unmap();
       this->file_size_ = file_size;
-      this->map();
+      if (!this->map_no_anonymous())
+       gold_fatal(_("%s: mmap: %s"), this->name_, strerror(errno));
     }
 }
 
-// Map the file into memory.
+// Map an anonymous block of memory which will later be written to the
+// file.  Return whether the map succeeded.
 
-void
-Output_file::map()
+bool
+Output_file::map_anonymous()
+{
+  void* base = ::mmap(NULL, this->file_size_, PROT_READ | PROT_WRITE,
+                     MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+  if (base != MAP_FAILED)
+    {
+      this->map_is_anonymous_ = true;
+      this->base_ = static_cast<unsigned char*>(base);
+      return true;
+    }
+  return false;
+}
+
+// Map the file into memory.  Return whether the mapping succeeded.
+
+bool
+Output_file::map_no_anonymous()
 {
   const int o = this->o_;
 
@@ -3381,28 +4443,52 @@ Output_file::map()
       || ::fstat(o, &statbuf) != 0
       || !S_ISREG(statbuf.st_mode)
       || this->is_temporary_)
-    {
-      this->map_is_anonymous_ = true;
-      base = ::mmap(NULL, this->file_size_, PROT_READ | PROT_WRITE,
-                    MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
-    }
-  else
-    {
-      // Write out one byte to make the file the right size.
-      if (::lseek(o, this->file_size_ - 1, SEEK_SET) < 0)
-        gold_fatal(_("%s: lseek: %s"), this->name_, strerror(errno));
-      char b = 0;
-      if (::write(o, &b, 1) != 1)
-        gold_fatal(_("%s: write: %s"), this->name_, strerror(errno));
+    return false;
 
-      // Map the file into memory.
-      this->map_is_anonymous_ = false;
-      base = ::mmap(NULL, this->file_size_, PROT_READ | PROT_WRITE,
-                    MAP_SHARED, o, 0);
-    }
+  // Ensure that we have disk space available for the file.  If we
+  // don't do this, it is possible that we will call munmap, close,
+  // and exit with dirty buffers still in the cache with no assigned
+  // disk blocks.  If the disk is out of space at that point, the
+  // output file will wind up incomplete, but we will have already
+  // exited.  The alternative to fallocate would be to use fdatasync,
+  // but that would be a more significant performance hit.
+  if (::posix_fallocate(o, 0, this->file_size_) < 0)
+    gold_fatal(_("%s: %s"), this->name_, strerror(errno));
+
+  // Map the file into memory.
+  base = ::mmap(NULL, this->file_size_, PROT_READ | PROT_WRITE,
+               MAP_SHARED, o, 0);
+
+  // The mmap call might fail because of file system issues: the file
+  // system might not support mmap at all, or it might not support
+  // mmap with PROT_WRITE.
   if (base == MAP_FAILED)
-    gold_fatal(_("%s: mmap: %s"), this->name_, strerror(errno));
+    return false;
+
+  this->map_is_anonymous_ = false;
   this->base_ = static_cast<unsigned char*>(base);
+  return true;
+}
+
+// Map the file into memory.
+
+void
+Output_file::map()
+{
+  if (this->map_no_anonymous())
+    return;
+
+  // The mmap call might fail because of file system issues: the file
+  // system might not support mmap at all, or it might not support
+  // mmap with PROT_WRITE.  I'm not sure which errno values we will
+  // see in all cases, so if the mmap fails for any reason and we
+  // don't care about file contents, try for an anonymous map.
+  if (this->map_anonymous())
+    return;
+
+  gold_fatal(_("%s: mmap: failed to allocate %lu bytes for output file: %s"),
+             this->name_, static_cast<unsigned long>(this->file_size_),
+             strerror(errno));
 }
 
 // Unmap the file from memory.
@@ -3424,15 +4510,20 @@ Output_file::close()
   if (this->map_is_anonymous_ && !this->is_temporary_)
     {
       size_t bytes_to_write = this->file_size_;
+      size_t offset = 0;
       while (bytes_to_write > 0)
         {
-          ssize_t bytes_written = ::write(this->o_, this->base_, bytes_to_write);
+          ssize_t bytes_written = ::write(this->o_, this->base_ + offset,
+                                          bytes_to_write);
           if (bytes_written == 0)
             gold_error(_("%s: write: unexpected 0 return-value"), this->name_);
           else if (bytes_written < 0)
             gold_error(_("%s: write: %s"), this->name_, strerror(errno));
           else
-            bytes_to_write -= bytes_written;
+            {
+              bytes_to_write -= bytes_written;
+              offset += bytes_written;
+            }
         }
     }
   this->unmap();
@@ -3453,6 +4544,7 @@ Output_file::close()
 template
 off_t
 Output_section::add_input_section<32, false>(
+    Layout* layout,
     Sized_relobj<32, false>* object,
     unsigned int shndx,
     const char* secname,
@@ -3465,6 +4557,7 @@ Output_section::add_input_section<32, false>(
 template
 off_t
 Output_section::add_input_section<32, true>(
+    Layout* layout,
     Sized_relobj<32, true>* object,
     unsigned int shndx,
     const char* secname,
@@ -3477,6 +4570,7 @@ Output_section::add_input_section<32, true>(
 template
 off_t
 Output_section::add_input_section<64, false>(
+    Layout* layout,
     Sized_relobj<64, false>* object,
     unsigned int shndx,
     const char* secname,
@@ -3489,6 +4583,7 @@ Output_section::add_input_section<64, false>(
 template
 off_t
 Output_section::add_input_section<64, true>(
+    Layout* layout,
     Sized_relobj<64, true>* object,
     unsigned int shndx,
     const char* secname,