]> git.ipfire.org Git - thirdparty/binutils-gdb.git/blobdiff - gold/output.cc
This commit was manufactured by cvs2svn to create branch 'binutils-
[thirdparty/binutils-gdb.git] / gold / output.cc
index 63ab98c96b6789de0a75c61d034716150b1de020..99890ebae1e9ec21dfa5a208640964243dd586cb 100644 (file)
@@ -1,6 +1,6 @@
 // output.cc -- manage the output file for gold
 
-// Copyright 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
+// Copyright 2006, 2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
 // Written by Ian Lance Taylor <iant@google.com>.
 
 // This file is part of gold.
 #include <cerrno>
 #include <fcntl.h>
 #include <unistd.h>
-#include <sys/mman.h>
 #include <sys/stat.h>
 #include <algorithm>
+
+#ifdef HAVE_SYS_MMAN_H
+#include <sys/mman.h>
+#endif
+
 #include "libiberty.h"
 
+#include "dwarf.h"
 #include "parameters.h"
 #include "object.h"
 #include "symtab.h"
 #include "reloc.h"
 #include "merge.h"
 #include "descriptors.h"
+#include "layout.h"
 #include "output.h"
 
+// For systems without mmap support.
+#ifndef HAVE_MMAP
+# define mmap gold_mmap
+# define munmap gold_munmap
+# define mremap gold_mremap
+# ifndef MAP_FAILED
+#  define MAP_FAILED (reinterpret_cast<void*>(-1))
+# endif
+# ifndef PROT_READ
+#  define PROT_READ 0
+# endif
+# ifndef PROT_WRITE
+#  define PROT_WRITE 0
+# endif
+# ifndef MAP_PRIVATE
+#  define MAP_PRIVATE 0
+# endif
+# ifndef MAP_ANONYMOUS
+#  define MAP_ANONYMOUS 0
+# endif
+# ifndef MAP_SHARED
+#  define MAP_SHARED 0
+# endif
+
+# ifndef ENOSYS
+#  define ENOSYS EINVAL
+# endif
+
+static void *
+gold_mmap(void *, size_t, int, int, int, off_t)
+{
+  errno = ENOSYS;
+  return MAP_FAILED;
+}
+
+static int
+gold_munmap(void *, size_t)
+{
+  errno = ENOSYS;
+  return -1;
+}
+
+static void *
+gold_mremap(void *, size_t, size_t, int)
+{
+  errno = ENOSYS;
+  return MAP_FAILED;
+}
+
+#endif
+
+#if defined(HAVE_MMAP) && !defined(HAVE_MREMAP)
+# define mremap gold_mremap
+extern "C" void *gold_mremap(void *, size_t, size_t, int);
+#endif
+
 // Some BSD systems still use MAP_ANON instead of MAP_ANONYMOUS
 #ifndef MAP_ANONYMOUS
 # 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)
+#ifndef MREMAP_MAYMOVE
+# define MREMAP_MAYMOVE 1
+#endif
+
+// Mingw does not have S_ISLNK.
+#ifndef S_ISLNK
+# define S_ISLNK(mode) 0
+#endif
 
 namespace gold
 {
 
+// A wrapper around posix_fallocate.  If we don't have posix_fallocate,
+// or the --no-posix-fallocate option is set, we try the fallocate
+// system call directly.  If that fails, we use ftruncate to set
+// the file size and hope that there is enough disk space.
+
+static int
+gold_fallocate(int o, off_t offset, off_t len)
+{
+#ifdef HAVE_POSIX_FALLOCATE
+  if (parameters->options().posix_fallocate())
+    return ::posix_fallocate(o, offset, len);
+#endif // defined(HAVE_POSIX_FALLOCATE)
+#ifdef HAVE_FALLOCATE
+  if (::fallocate(o, 0, offset, len) == 0)
+    return 0;
+#endif // defined(HAVE_FALLOCATE)
+  if (::ftruncate(o, offset + len) < 0)
+    return errno;
+  return 0;
+}
+
 // Output_data variables.
 
 bool Output_data::allocated_sizes_are_fixed;
@@ -213,7 +293,9 @@ 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);
   }
@@ -278,6 +360,7 @@ Output_segment_headers::Output_segment_headers(
     const Layout::Segment_list& segment_list)
   : segment_list_(segment_list)
 {
+  this->set_current_data_size_for_child(this->do_size());
 }
 
 void
@@ -353,14 +436,12 @@ Output_segment_headers::do_size() const
 
 Output_file_header::Output_file_header(const Target* target,
                                       const Symbol_table* symtab,
-                                      const Output_segment_headers* osh,
-                                      const char* entry)
+                                      const Output_segment_headers* osh)
   : target_(target),
     symtab_(symtab),
     segment_header_(osh),
     section_header_(NULL),
-    shstrtab_(NULL),
-    entry_(entry)
+    shstrtab_(NULL)
 {
   this->set_data_size(this->do_size());
 }
@@ -409,7 +490,7 @@ Output_file_header::do_write(Output_file* of)
     }
 }
 
-// Write out the file header with appropriate size and endianess.
+// Write out the file header with appropriate size and endianness.
 
 template<int size, bool big_endian>
 void
@@ -470,8 +551,11 @@ 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);
@@ -497,22 +581,16 @@ Output_file_header::do_sized_write(Output_file* of)
   of->write_output_view(0, ehdr_size, view);
 }
 
-// Return the value to use for the entry address.  THIS->ENTRY_ is the
-// symbol specified on the command line, if any.
+// Return the value to use for the entry address.
 
 template<int size>
 typename elfcpp::Elf_types<size>::Elf_Addr
 Output_file_header::entry()
 {
-  const bool should_issue_warning = (this->entry_ != NULL
+  const bool should_issue_warning = (parameters->options().entry() != NULL
                                     && !parameters->options().relocatable()
                                      && !parameters->options().shared());
-
-  // FIXME: Need to support target specific entry symbol.
-  const char* entry = this->entry_;
-  if (entry == NULL)
-    entry = "_start";
-
+  const char* entry = parameters->entry();
   Symbol* sym = this->symtab_->lookup(entry);
 
   typename Sized_symbol<size>::Value_type v;
@@ -633,9 +711,12 @@ 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,
+    bool use_plt_offset)
   : 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), use_plt_offset_(use_plt_offset), shndx_(INVALID_CODE)
 {
   // this->type_ is a bitfield; make sure TYPE fits.
   gold_assert(this->type_ == type);
@@ -652,9 +733,12 @@ 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,
+    bool use_plt_offset)
   : 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), use_plt_offset_(use_plt_offset), shndx_(shndx)
 {
   gold_assert(shndx != INVALID_CODE);
   // this->type_ is a bitfield; make sure TYPE fits.
@@ -675,9 +759,12 @@ Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::Output_reloc(
     Output_data* od,
     Address address,
     bool is_relative,
-    bool is_section_symbol)
+    bool is_symbolless,
+    bool is_section_symbol,
+    bool use_plt_offset)
   : address_(address), local_sym_index_(local_sym_index), type_(type),
-    is_relative_(is_relative), is_section_symbol_(is_section_symbol),
+    is_relative_(is_relative), is_symbolless_(is_symbolless),
+    is_section_symbol_(is_section_symbol), use_plt_offset_(use_plt_offset),
     shndx_(INVALID_CODE)
 {
   gold_assert(local_sym_index != GSYM_CODE
@@ -698,9 +785,12 @@ Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::Output_reloc(
     unsigned int shndx,
     Address address,
     bool is_relative,
-    bool is_section_symbol)
+    bool is_symbolless,
+    bool is_section_symbol,
+    bool use_plt_offset)
   : address_(address), local_sym_index_(local_sym_index), type_(type),
-    is_relative_(is_relative), is_section_symbol_(is_section_symbol),
+    is_relative_(is_relative), is_symbolless_(is_symbolless),
+    is_section_symbol_(is_section_symbol), use_plt_offset_(use_plt_offset),
     shndx_(shndx)
 {
   gold_assert(local_sym_index != GSYM_CODE
@@ -723,7 +813,8 @@ 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), use_plt_offset_(false), shndx_(INVALID_CODE)
 {
   // this->type_ is a bitfield; make sure TYPE fits.
   gold_assert(this->type_ == type);
@@ -743,7 +834,8 @@ 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), use_plt_offset_(false), shndx_(shndx)
 {
   gold_assert(shndx != INVALID_CODE);
   // this->type_ is a bitfield; make sure TYPE fits.
@@ -756,6 +848,76 @@ 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), use_plt_offset_(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), use_plt_offset_(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), use_plt_offset_(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), use_plt_offset_(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>
@@ -763,7 +925,7 @@ 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_)
     {
@@ -778,16 +940,23 @@ 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;
 
     default:
       {
         const unsigned int lsi = this->local_sym_index_;
+       Sized_relobj_file<size, big_endian>* relobj =
+           this->u1_.relobj->sized_relobj();
+       gold_assert(relobj != NULL);
         if (!this->is_section_symbol_)
-          this->u1_.relobj->set_needs_output_dynsym_entry(lsi);
+          relobj->set_needs_output_dynsym_entry(lsi);
         else
-          this->u1_.relobj->output_section(lsi)->set_needs_dynsym_index();
+          relobj->output_section(lsi)->set_needs_dynsym_index();
       }
       break;
     }
@@ -801,6 +970,8 @@ 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:
@@ -822,6 +993,11 @@ 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;
@@ -830,16 +1006,19 @@ Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::get_symbol_index()
     default:
       {
         const unsigned int lsi = this->local_sym_index_;
+       Sized_relobj_file<size, big_endian>* relobj =
+           this->u1_.relobj->sized_relobj();
+       gold_assert(relobj != NULL);
         if (!this->is_section_symbol_)
           {
             if (dynamic)
-              index = this->u1_.relobj->dynsym_index(lsi);
+              index = relobj->dynsym_index(lsi);
             else
-              index = this->u1_.relobj->symtab_index(lsi);
+              index = relobj->symtab_index(lsi);
           }
         else
           {
-            Output_section* os = this->u1_.relobj->output_section(lsi);
+            Output_section* os = relobj->output_section(lsi);
             gold_assert(os != NULL);
             if (dynamic)
               index = os->dynsym_index();
@@ -863,7 +1042,9 @@ 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);
@@ -872,7 +1053,10 @@ Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::
   if (offset != invalid_address)
     return offset + addend;
   // This is a merge section.
-  offset = os->output_address(this->u1_.relobj, lsi, addend);
+  Sized_relobj_file<size, big_endian>* relobj =
+      this->u1_.relobj->sized_relobj();
+  gold_assert(relobj != NULL);
+  offset = os->output_address(relobj, lsi, addend);
   gold_assert(offset != invalid_address);
   return offset;
 }
@@ -893,8 +1077,10 @@ Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::get_address() const
        address += os->address() + off;
       else
        {
-         address = os->output_address(this->u2_.relobj, this->shndx_,
-                                      address);
+         Sized_relobj_file<size, big_endian>* relobj =
+             this->u2_.relobj->sized_relobj();
+         gold_assert(relobj != NULL);
+         address = os->output_address(relobj, this->shndx_, address);
          gold_assert(address != invalid_address);
        }
     }
@@ -913,7 +1099,7 @@ 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_));
 }
 
@@ -939,14 +1125,32 @@ Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::symbol_value(
     {
       const Sized_symbol<size>* sym;
       sym = static_cast<const Sized_symbol<size>*>(this->u1_.gsym);
-      return sym->value() + addend;
+      if (this->use_plt_offset_ && sym->has_plt_offset())
+       {
+         uint64_t plt_address =
+           parameters->target().plt_address_for_global(sym);
+         return plt_address + sym->plt_offset();
+       }
+      else
+       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);
-  return symval->value(this->u1_.relobj, addend);
+  Sized_relobj_file<size, big_endian>* relobj =
+      this->u1_.relobj->sized_relobj();
+  gold_assert(relobj != NULL);
+  if (this->use_plt_offset_)
+    {
+      uint64_t plt_address =
+         parameters->target().plt_address_for_local(relobj, lsi);
+      return plt_address + relobj->local_plt_offset(lsi);
+    }
+  const Symbol_value<size>* symval = relobj->local_symbol(lsi);
+  return symval->value(relobj, addend);
 }
 
 // Reloc comparison.  This function sorts the dynamic relocs for the
@@ -1010,7 +1214,10 @@ 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);
@@ -1032,10 +1239,17 @@ Output_data_reloc_base<sh_type, dynamic, size, big_endian>
     os->set_entsize(elfcpp::Elf_sizes<size>::rela_size);
   else
     gold_unreachable();
-  if (dynamic)
-    os->set_should_link_to_dynsym();
-  else
+
+  // A STT_GNU_IFUNC symbol may require a IRELATIVE reloc when doing a
+  // static link.  The backends will generate a dynamic reloc section
+  // to hold this.  In that case we don't want to link to the dynsym
+  // section, because there isn't one.
+  if (!dynamic)
     os->set_should_link_to_symtab();
+  else if (parameters->doing_static_link())
+    ;
+  else
+    os->set_should_link_to_dynsym();
 }
 
 // Write out relocation data.
@@ -1049,7 +1263,7 @@ 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(),
@@ -1087,7 +1301,7 @@ Output_relocatable_relocs<sh_type, size, big_endian>::set_final_data_size()
 
 template<int size, bool big_endian>
 Output_data_group<size, big_endian>::Output_data_group(
-    Sized_relobj<size, big_endian>* relobj,
+    Sized_relobj_file<size, big_endian>* relobj,
     section_size_type entry_count,
     elfcpp::Elf_Word flags,
     std::vector<unsigned int>* input_shndxes)
@@ -1161,12 +1375,18 @@ Output_data_got<size, big_endian>::Got_entry::write(unsigned char* pov) const
        // link-time value, which will be relocated dynamically by a
        // RELATIVE relocation.
        Symbol* gsym = this->u_.gsym;
-       Sized_symbol<size>* sgsym;
-       // This cast is a bit ugly.  We don't want to put a
-       // virtual method in Symbol, because we want Symbol to be
-       // as small as possible.
-       sgsym = static_cast<Sized_symbol<size>*>(gsym);
-       val = sgsym->value();
+       if (this->use_plt_offset_ && gsym->has_plt_offset())
+         val = (parameters->target().plt_address_for_global(gsym)
+                + gsym->plt_offset());
+       else
+         {
+           Sized_symbol<size>* sgsym;
+           // This cast is a bit ugly.  We don't want to put a
+           // virtual method in Symbol, because we want Symbol to be
+           // as small as possible.
+           sgsym = static_cast<Sized_symbol<size>*>(gsym);
+           val = sgsym->value();
+         }
       }
       break;
 
@@ -1174,11 +1394,28 @@ Output_data_got<size, big_endian>::Got_entry::write(unsigned char* pov) const
       val = this->u_.constant;
       break;
 
+    case RESERVED_CODE:
+      // If we're doing an incremental update, don't touch this GOT entry.
+      if (parameters->incremental_update())
+        return;
+      val = this->u_.constant;
+      break;
+
     default:
       {
+       const Relobj* object = this->u_.object;
         const unsigned int lsi = this->local_sym_index_;
-        const Symbol_value<size>* symval = this->u_.object->local_symbol(lsi);
-        val = symval->value(this->u_.object, 0);
+       if (!this->use_plt_offset_)
+         {
+           uint64_t lval = object->local_symbol_value(lsi, 0);
+           val = convert_types<Valtype, uint64_t>(lval);
+         }
+       else
+         {
+           uint64_t plt_address =
+             parameters->target().plt_address_for_local(object, lsi);
+           val = plt_address + object->local_plt_offset(lsi);
+         }
       }
       break;
     }
@@ -1201,48 +1438,43 @@ Output_data_got<size, big_endian>::add_global(
   if (gsym->has_got_offset(got_type))
     return false;
 
-  this->entries_.push_back(Got_entry(gsym));
-  this->set_got_size();
-  gsym->set_got_offset(got_type, this->last_got_offset());
+  unsigned int got_offset = this->add_got_entry(Got_entry(gsym, false));
+  gsym->set_got_offset(got_type, got_offset);
   return true;
 }
 
-// Add an entry for a global symbol to the GOT, and add a dynamic
-// relocation of type R_TYPE for the GOT entry.
+// Like add_global, but use the PLT offset.
+
 template<int size, bool big_endian>
-void
-Output_data_got<size, big_endian>::add_global_with_rel(
-    Symbol* gsym,
-    unsigned int got_type,
-    Rel_dyn* rel_dyn,
-    unsigned int r_type)
+bool
+Output_data_got<size, big_endian>::add_global_plt(Symbol* gsym,
+                                                 unsigned int got_type)
 {
   if (gsym->has_got_offset(got_type))
-    return;
+    return false;
 
-  this->entries_.push_back(Got_entry());
-  this->set_got_size();
-  unsigned int got_offset = this->last_got_offset();
+  unsigned int got_offset = this->add_got_entry(Got_entry(gsym, true));
   gsym->set_got_offset(got_type, got_offset);
-  rel_dyn->add_global(gsym, r_type, this, got_offset);
+  return true;
 }
 
+// Add an entry for a global symbol to the GOT, and add a dynamic
+// relocation of type R_TYPE for the GOT entry.
+
 template<int size, bool big_endian>
 void
-Output_data_got<size, big_endian>::add_global_with_rela(
+Output_data_got<size, big_endian>::add_global_with_rel(
     Symbol* gsym,
     unsigned int got_type,
-    Rela_dyn* rela_dyn,
+    Output_data_reloc_generic* rel_dyn,
     unsigned int r_type)
 {
   if (gsym->has_got_offset(got_type))
     return;
 
-  this->entries_.push_back(Got_entry());
-  this->set_got_size();
-  unsigned int got_offset = this->last_got_offset();
+  unsigned int got_offset = this->add_got_entry(Got_entry());
   gsym->set_got_offset(got_type, got_offset);
-  rela_dyn->add_global(gsym, r_type, this, got_offset, 0);
+  rel_dyn->add_global_generic(gsym, r_type, this, got_offset, 0);
 }
 
 // Add a pair of entries for a global symbol to the GOT, and add
@@ -1253,53 +1485,20 @@ void
 Output_data_got<size, big_endian>::add_global_pair_with_rel(
     Symbol* gsym,
     unsigned int got_type,
-    Rel_dyn* rel_dyn,
+    Output_data_reloc_generic* rel_dyn,
     unsigned int r_type_1,
     unsigned int r_type_2)
 {
   if (gsym->has_got_offset(got_type))
     return;
 
-  this->entries_.push_back(Got_entry());
-  unsigned int got_offset = this->last_got_offset();
+  unsigned int got_offset = this->add_got_entry_pair(Got_entry(), Got_entry());
   gsym->set_got_offset(got_type, got_offset);
-  rel_dyn->add_global(gsym, r_type_1, this, got_offset);
+  rel_dyn->add_global_generic(gsym, r_type_1, this, got_offset, 0);
 
-  this->entries_.push_back(Got_entry());
   if (r_type_2 != 0)
-    {
-      got_offset = this->last_got_offset();
-      rel_dyn->add_global(gsym, r_type_2, this, got_offset);
-    }
-
-  this->set_got_size();
-}
-
-template<int size, bool big_endian>
-void
-Output_data_got<size, big_endian>::add_global_pair_with_rela(
-    Symbol* gsym,
-    unsigned int got_type,
-    Rela_dyn* rela_dyn,
-    unsigned int r_type_1,
-    unsigned int r_type_2)
-{
-  if (gsym->has_got_offset(got_type))
-    return;
-
-  this->entries_.push_back(Got_entry());
-  unsigned int got_offset = this->last_got_offset();
-  gsym->set_got_offset(got_type, got_offset);
-  rela_dyn->add_global(gsym, r_type_1, this, got_offset, 0);
-
-  this->entries_.push_back(Got_entry());
-  if (r_type_2 != 0)
-    {
-      got_offset = this->last_got_offset();
-      rela_dyn->add_global(gsym, r_type_2, this, got_offset, 0);
-    }
-
-  this->set_got_size();
+    rel_dyn->add_global_generic(gsym, r_type_2, this,
+                               got_offset + size / 8, 0);
 }
 
 // Add an entry for a local symbol to the GOT.  This returns true if
@@ -1309,57 +1508,55 @@ Output_data_got<size, big_endian>::add_global_pair_with_rela(
 template<int size, bool big_endian>
 bool
 Output_data_got<size, big_endian>::add_local(
-    Sized_relobj<size, big_endian>* object,
+    Relobj* object,
     unsigned int symndx,
     unsigned int got_type)
 {
   if (object->local_has_got_offset(symndx, got_type))
     return false;
 
-  this->entries_.push_back(Got_entry(object, symndx));
-  this->set_got_size();
-  object->set_local_got_offset(symndx, got_type, this->last_got_offset());
+  unsigned int got_offset = this->add_got_entry(Got_entry(object, symndx,
+                                                         false));
+  object->set_local_got_offset(symndx, got_type, got_offset);
   return true;
 }
 
-// Add an entry for a local symbol to the GOT, and add a dynamic
-// relocation of type R_TYPE for the GOT entry.
+// Like add_local, but use the PLT offset.
+
 template<int size, bool big_endian>
-void
-Output_data_got<size, big_endian>::add_local_with_rel(
-    Sized_relobj<size, big_endian>* object,
+bool
+Output_data_got<size, big_endian>::add_local_plt(
+    Relobj* object,
     unsigned int symndx,
-    unsigned int got_type,
-    Rel_dyn* rel_dyn,
-    unsigned int r_type)
+    unsigned int got_type)
 {
   if (object->local_has_got_offset(symndx, got_type))
-    return;
+    return false;
 
-  this->entries_.push_back(Got_entry());
-  this->set_got_size();
-  unsigned int got_offset = this->last_got_offset();
+  unsigned int got_offset = this->add_got_entry(Got_entry(object, symndx,
+                                                         true));
   object->set_local_got_offset(symndx, got_type, got_offset);
-  rel_dyn->add_local(object, symndx, r_type, this, got_offset);
+  return true;
 }
 
+// Add an entry for a local symbol to the GOT, and add a dynamic
+// relocation of type R_TYPE for the GOT entry.
+
 template<int size, bool big_endian>
 void
-Output_data_got<size, big_endian>::add_local_with_rela(
-    Sized_relobj<size, big_endian>* object,
+Output_data_got<size, big_endian>::add_local_with_rel(
+    Relobj* object,
     unsigned int symndx,
     unsigned int got_type,
-    Rela_dyn* rela_dyn,
+    Output_data_reloc_generic* rel_dyn,
     unsigned int r_type)
 {
   if (object->local_has_got_offset(symndx, got_type))
     return;
 
-  this->entries_.push_back(Got_entry());
-  this->set_got_size();
-  unsigned int got_offset = this->last_got_offset();
+  unsigned int got_offset = this->add_got_entry(Got_entry());
   object->set_local_got_offset(symndx, got_type, got_offset);
-  rela_dyn->add_local(object, symndx, r_type, this, got_offset, 0);
+  rel_dyn->add_local_generic(object, symndx, r_type, this, got_offset, 0);
 }
 
 // Add a pair of entries for a local symbol to the GOT, and add
@@ -1368,61 +1565,54 @@ Output_data_got<size, big_endian>::add_local_with_rela(
 template<int size, bool big_endian>
 void
 Output_data_got<size, big_endian>::add_local_pair_with_rel(
-    Sized_relobj<size, big_endian>* object,
+    Relobj* object,
     unsigned int symndx,
     unsigned int shndx,
     unsigned int got_type,
-    Rel_dyn* rel_dyn,
+    Output_data_reloc_generic* rel_dyn,
     unsigned int r_type_1,
     unsigned int r_type_2)
 {
   if (object->local_has_got_offset(symndx, got_type))
     return;
 
-  this->entries_.push_back(Got_entry());
-  unsigned int got_offset = this->last_got_offset();
+  unsigned int got_offset =
+      this->add_got_entry_pair(Got_entry(),
+                              Got_entry(object, symndx, false));
   object->set_local_got_offset(symndx, got_type, got_offset);
   Output_section* os = object->output_section(shndx);
-  rel_dyn->add_output_section(os, r_type_1, this, got_offset);
+  rel_dyn->add_output_section_generic(os, r_type_1, this, got_offset, 0);
 
-  this->entries_.push_back(Got_entry(object, symndx));
   if (r_type_2 != 0)
-    {
-      got_offset = this->last_got_offset();
-      rel_dyn->add_output_section(os, r_type_2, this, got_offset);
-    }
-
-  this->set_got_size();
+    rel_dyn->add_output_section_generic(os, r_type_2, this,
+                                       got_offset + size / 8, 0);
 }
 
+// Reserve a slot in the GOT for a local symbol or the second slot of a pair.
+
 template<int size, bool big_endian>
 void
-Output_data_got<size, big_endian>::add_local_pair_with_rela(
-    Sized_relobj<size, big_endian>* object,
-    unsigned int symndx,
-    unsigned int shndx,
-    unsigned int got_type,
-    Rela_dyn* rela_dyn,
-    unsigned int r_type_1,
-    unsigned int r_type_2)
+Output_data_got<size, big_endian>::reserve_local(
+    unsigned int i,
+    Relobj* object,
+    unsigned int sym_index,
+    unsigned int got_type)
 {
-  if (object->local_has_got_offset(symndx, got_type))
-    return;
-
-  this->entries_.push_back(Got_entry());
-  unsigned int got_offset = this->last_got_offset();
-  object->set_local_got_offset(symndx, got_type, got_offset);
-  Output_section* os = object->output_section(shndx);
-  rela_dyn->add_output_section(os, r_type_1, this, got_offset, 0);
+  this->do_reserve_slot(i);
+  object->set_local_got_offset(sym_index, got_type, this->got_offset(i));
+}
 
-  this->entries_.push_back(Got_entry(object, symndx));
-  if (r_type_2 != 0)
-    {
-      got_offset = this->last_got_offset();
-      rela_dyn->add_output_section(os, r_type_2, this, got_offset, 0);
-    }
+// Reserve a slot in the GOT for a global symbol.
 
-  this->set_got_size();
+template<int size, bool big_endian>
+void
+Output_data_got<size, big_endian>::reserve_global(
+    unsigned int i,
+    Symbol* gsym,
+    unsigned int got_type)
+{
+  this->do_reserve_slot(i);
+  gsym->set_got_offset(got_type, this->got_offset(i));
 }
 
 // Write out the GOT.
@@ -1454,6 +1644,63 @@ Output_data_got<size, big_endian>::do_write(Output_file* of)
   this->entries_.clear();
 }
 
+// Create a new GOT entry and return its offset.
+
+template<int size, bool big_endian>
+unsigned int
+Output_data_got<size, big_endian>::add_got_entry(Got_entry got_entry)
+{
+  if (!this->is_data_size_valid())
+    {
+      this->entries_.push_back(got_entry);
+      this->set_got_size();
+      return this->last_got_offset();
+    }
+  else
+    {
+      // For an incremental update, find an available slot.
+      off_t got_offset = this->free_list_.allocate(size / 8, size / 8, 0);
+      if (got_offset == -1)
+       gold_fallback(_("out of patch space (GOT);"
+                       " relink with --incremental-full"));
+      unsigned int got_index = got_offset / (size / 8);
+      gold_assert(got_index < this->entries_.size());
+      this->entries_[got_index] = got_entry;
+      return static_cast<unsigned int>(got_offset);
+    }
+}
+
+// Create a pair of new GOT entries and return the offset of the first.
+
+template<int size, bool big_endian>
+unsigned int
+Output_data_got<size, big_endian>::add_got_entry_pair(Got_entry got_entry_1,
+                                                     Got_entry got_entry_2)
+{
+  if (!this->is_data_size_valid())
+    {
+      unsigned int got_offset;
+      this->entries_.push_back(got_entry_1);
+      got_offset = this->last_got_offset();
+      this->entries_.push_back(got_entry_2);
+      this->set_got_size();
+      return got_offset;
+    }
+  else
+    {
+      // For an incremental update, find an available pair of slots.
+      off_t got_offset = this->free_list_.allocate(2 * size / 8, size / 8, 0);
+      if (got_offset == -1)
+       gold_fallback(_("out of patch space (GOT);"
+                       " relink with --incremental-full"));
+      unsigned int got_index = got_offset / (size / 8);
+      gold_assert(got_index < this->entries_.size());
+      this->entries_[got_index] = got_entry_1;
+      this->entries_[got_index + 1] = got_entry_2;
+      return static_cast<unsigned int>(got_offset);
+    }
+}
+
 // Output_data_dynamic::Dynamic_entry methods.
 
 // Write out the entry.
@@ -1473,6 +1720,8 @@ 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:
@@ -1519,9 +1768,13 @@ Output_data_dynamic::set_final_data_size()
 {
   // 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_.rbegin()->tag() != elfcpp::DT_NULL)
-    this->add_constant(elfcpp::DT_NULL, 0);
+  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)
@@ -1628,48 +1881,235 @@ Output_symtab_xindex::endian_do_write(unsigned char* const oview)
     }
 }
 
-// Output_section::Input_section methods.
+// Output_fill_debug_info methods.
 
-// Return the data size.  For an input section we store the size here.
-// For an Output_section_data, we have to ask it for the size.
+// Return the minimum size needed for a dummy compilation unit header.
 
-off_t
-Output_section::Input_section::data_size() const
+size_t
+Output_fill_debug_info::do_minimum_hole_size() const
 {
-  if (this->is_input_section())
-    return this->u1_.data_size;
-  else
-    return this->u2_.posd->data_size();
+  // Compile unit header fields: unit_length, version, debug_abbrev_offset,
+  // address_size.
+  const size_t len = 4 + 2 + 4 + 1;
+  // For type units, add type_signature, type_offset.
+  if (this->is_debug_types_)
+    return len + 8 + 4;
+  return len;
 }
 
-// Set the address and file offset.
+// Write a dummy compilation unit header to fill a hole in the
+// .debug_info or .debug_types section.
 
 void
-Output_section::Input_section::set_address_and_file_offset(
-    uint64_t address,
-    off_t file_offset,
-    off_t section_file_offset)
+Output_fill_debug_info::do_write(Output_file* of, off_t off, size_t len) const
 {
-  if (this->is_input_section())
-    this->u2_.object->set_section_offset(this->shndx_,
-                                        file_offset - section_file_offset);
+  gold_debug(DEBUG_INCREMENTAL, "fill_debug_info(%08lx, %08lx)",
+            static_cast<long>(off), static_cast<long>(len));
+
+  gold_assert(len >= this->do_minimum_hole_size());
+
+  unsigned char* const oview = of->get_output_view(off, len);
+  unsigned char* pov = oview;
+
+  // Write header fields: unit_length, version, debug_abbrev_offset,
+  // address_size.
+  if (this->is_big_endian())
+    {
+      elfcpp::Swap_unaligned<32, true>::writeval(pov, len - 4);
+      elfcpp::Swap_unaligned<16, true>::writeval(pov + 4, this->version);
+      elfcpp::Swap_unaligned<32, true>::writeval(pov + 6, 0);
+    }
   else
-    this->u2_.posd->set_address_and_file_offset(address, file_offset);
+    {
+      elfcpp::Swap_unaligned<32, false>::writeval(pov, len - 4);
+      elfcpp::Swap_unaligned<16, false>::writeval(pov + 4, this->version);
+      elfcpp::Swap_unaligned<32, false>::writeval(pov + 6, 0);
+    }
+  pov += 4 + 2 + 4;
+  *pov++ = 4;
+
+  // For type units, the additional header fields -- type_signature,
+  // type_offset -- can be filled with zeroes.
+
+  // Fill the remainder of the free space with zeroes.  The first
+  // zero should tell the consumer there are no DIEs to read in this
+  // compilation unit.
+  if (pov < oview + len)
+    memset(pov, 0, oview + len - pov);
+
+  of->write_output_view(off, len, oview);
 }
 
-// Reset the address and file offset.
+// Output_fill_debug_line methods.
 
-void
-Output_section::Input_section::reset_address_and_file_offset()
+// Return the minimum size needed for a dummy line number program header.
+
+size_t
+Output_fill_debug_line::do_minimum_hole_size() const
 {
-  if (!this->is_input_section())
-    this->u2_.posd->reset_address_and_file_offset();
+  // Line number program header fields: unit_length, version, header_length,
+  // minimum_instruction_length, default_is_stmt, line_base, line_range,
+  // opcode_base, standard_opcode_lengths[], include_directories, filenames.
+  const size_t len = 4 + 2 + 4 + this->header_length;
+  return len;
 }
 
-// Finalize the data size.
+// Write a dummy line number program header to fill a hole in the
+// .debug_line section.
 
 void
-Output_section::Input_section::finalize_data_size()
+Output_fill_debug_line::do_write(Output_file* of, off_t off, size_t len) const
+{
+  gold_debug(DEBUG_INCREMENTAL, "fill_debug_line(%08lx, %08lx)",
+            static_cast<long>(off), static_cast<long>(len));
+
+  gold_assert(len >= this->do_minimum_hole_size());
+
+  unsigned char* const oview = of->get_output_view(off, len);
+  unsigned char* pov = oview;
+
+  // Write header fields: unit_length, version, header_length,
+  // minimum_instruction_length, default_is_stmt, line_base, line_range,
+  // opcode_base, standard_opcode_lengths[], include_directories, filenames.
+  // We set the header_length field to cover the entire hole, so the
+  // line number program is empty.
+  if (this->is_big_endian())
+    {
+      elfcpp::Swap_unaligned<32, true>::writeval(pov, len - 4);
+      elfcpp::Swap_unaligned<16, true>::writeval(pov + 4, this->version);
+      elfcpp::Swap_unaligned<32, true>::writeval(pov + 6, len - (4 + 2 + 4));
+    }
+  else
+    {
+      elfcpp::Swap_unaligned<32, false>::writeval(pov, len - 4);
+      elfcpp::Swap_unaligned<16, false>::writeval(pov + 4, this->version);
+      elfcpp::Swap_unaligned<32, false>::writeval(pov + 6, len - (4 + 2 + 4));
+    }
+  pov += 4 + 2 + 4;
+  *pov++ = 1;  // minimum_instruction_length
+  *pov++ = 0;  // default_is_stmt
+  *pov++ = 0;  // line_base
+  *pov++ = 5;  // line_range
+  *pov++ = 13; // opcode_base
+  *pov++ = 0;  // standard_opcode_lengths[1]
+  *pov++ = 1;  // standard_opcode_lengths[2]
+  *pov++ = 1;  // standard_opcode_lengths[3]
+  *pov++ = 1;  // standard_opcode_lengths[4]
+  *pov++ = 1;  // standard_opcode_lengths[5]
+  *pov++ = 0;  // standard_opcode_lengths[6]
+  *pov++ = 0;  // standard_opcode_lengths[7]
+  *pov++ = 0;  // standard_opcode_lengths[8]
+  *pov++ = 1;  // standard_opcode_lengths[9]
+  *pov++ = 0;  // standard_opcode_lengths[10]
+  *pov++ = 0;  // standard_opcode_lengths[11]
+  *pov++ = 1;  // standard_opcode_lengths[12]
+  *pov++ = 0;  // include_directories (empty)
+  *pov++ = 0;  // filenames (empty)
+
+  // Some consumers don't check the header_length field, and simply
+  // start reading the line number program immediately following the
+  // header.  For those consumers, we fill the remainder of the free
+  // space with DW_LNS_set_basic_block opcodes.  These are effectively
+  // no-ops: the resulting line table program will not create any rows.
+  if (pov < oview + len)
+    memset(pov, elfcpp::DW_LNS_set_basic_block, oview + len - pov);
+
+  of->write_output_view(off, len, oview);
+}
+
+// Output_section::Input_section methods.
+
+// Return the current data size.  For an input section we store the size here.
+// For an Output_section_data, we have to ask it for the size.
+
+off_t
+Output_section::Input_section::current_data_size() const
+{
+  if (this->is_input_section())
+    return this->u1_.data_size;
+  else
+    {
+      this->u2_.posd->pre_finalize_data_size();
+      return this->u2_.posd->current_data_size();
+    }
+}
+
+// Return the data size.  For an input section we store the size here.
+// For an Output_section_data, we have to ask it for the size.
+
+off_t
+Output_section::Input_section::data_size() const
+{
+  if (this->is_input_section())
+    return this->u1_.data_size;
+  else
+    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
+Output_section::Input_section::set_address_and_file_offset(
+    uint64_t address,
+    off_t file_offset,
+    off_t section_file_offset)
+{
+  if (this->is_input_section())
+    this->u2_.object->set_section_offset(this->shndx_,
+                                        file_offset - section_file_offset);
+  else
+    this->u2_.posd->set_address_and_file_offset(address, file_offset);
+}
+
+// Reset the address and file offset.
+
+void
+Output_section::Input_section::reset_address_and_file_offset()
+{
+  if (!this->is_input_section())
+    this->u2_.posd->reset_address_and_file_offset();
+}
+
+// Finalize the data size.
+
+void
+Output_section::Input_section::finalize_data_size()
 {
   if (!this->is_input_section())
     this->u2_.posd->finalize_data_size();
@@ -1684,7 +2124,7 @@ Output_section::Input_section::output_offset(
     const Relobj* object,
     unsigned int shndx,
     section_offset_type offset,
-    section_offset_type *poutput) const
+    section_offset_typepoutput) const
 {
   if (!this->is_input_section())
     return this->u2_.posd->output_offset(object, shndx, offset, poutput);
@@ -1774,6 +2214,7 @@ Output_section::Output_section(const char* name, elfcpp::Elf_Word type,
     info_(0),
     type_(type),
     flags_(flags),
+    order_(ORDER_INVALID),
     out_shndx_(-1U),
     symtab_index_(0),
     dynsym_index_(0),
@@ -1790,25 +2231,26 @@ 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),
-    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),
+    always_keeps_input_sections_(false),
+    has_fixed_layout_(false),
+    is_patch_space_allowed_(false),
     tls_offset_(0),
     checkpoint_(NULL),
-    merge_section_map_(),
-    merge_section_by_properties_map_(),
-    relaxed_input_section_map_(),
-    is_relaxed_input_section_map_valid_(true)
+    lookup_maps_(new Output_section_lookup_maps),
+    free_list_(),
+    free_space_fill_(NULL),
+    patch_space_(0)
 {
   // An unallocated section has no address.  Forcing this means that
   // we don't need special treatment for symbols defined in debug
@@ -1852,7 +2294,8 @@ 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_file<size, big_endian>* object,
                                  unsigned int shndx,
                                  const char* secname,
                                  const elfcpp::Shdr<size, big_endian>& shdr,
@@ -1888,12 +2331,20 @@ Output_section::add_input_section(Sized_relobj<size, big_endian>* object,
   // 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
   // mess up the mappings, and are useless anyhow.
+  // FIXME: Need to handle merge sections during incremental update.
   if ((sh_flags & elfcpp::SHF_MERGE) != 0
       && reloc_shndx == 0
-      && shdr.get_sh_size() > 0)
+      && shdr.get_sh_size() > 0
+      && !parameters->incremental())
     {
-      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 = (this->always_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.
@@ -1901,18 +2352,43 @@ Output_section::add_input_section(Sized_relobj<size, big_endian>* object,
        }
     }
 
-  off_t offset_in_section = this->current_data_size_for_child();
-  off_t aligned_offset_in_section = align_address(offset_in_section,
-                                                  addralign);
+  section_size_type input_section_size = shdr.get_sh_size();
+  section_size_type uncompressed_size;
+  if (object->section_is_compressed(shndx, &uncompressed_size))
+    input_section_size = uncompressed_size;
+
+  off_t offset_in_section;
+  off_t aligned_offset_in_section;
+  if (this->has_fixed_layout())
+    {
+      // For incremental updates, find a chunk of unused space in the section.
+      offset_in_section = this->free_list_.allocate(input_section_size,
+                                                   addralign, 0);
+      if (offset_in_section == -1)
+        gold_fallback(_("out of patch space in section %s; "
+                       "relink with --incremental-full"),
+                     this->name());
+      aligned_offset_in_section = offset_in_section;
+    }
+  else
+    {
+      offset_in_section = this->current_data_size_for_child();
+      aligned_offset_in_section = align_address(offset_in_section,
+                                               addralign);
+      this->set_current_data_size_for_child(aligned_offset_in_section
+                                           + input_section_size);
+    }
 
   // 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.
+  // generating to avoid adjusting them during relaxation.  Also, if we are
+  // sorting input sections we must delay fill generation.
   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())
+      && (parameters->target().may_relax()
+          || layout->is_section_ordering_specified()))
     {
       gold_assert(this->fills_.empty());
       this->generate_code_fills_at_write_ = true;
@@ -1938,22 +2414,45 @@ Output_section::add_input_section(Sized_relobj<size, big_endian>* object,
         }
     }
 
-  this->set_current_data_size_for_child(aligned_offset_in_section
-                                       + shdr.get_sh_size());
-
   // 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.
-  if (have_sections_script
+  // 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 (this->always_keeps_input_sections_
+      || have_sections_script
       || !this->input_sections_.empty()
       || this->may_sort_attached_input_sections()
       || this->must_sort_attached_input_sections()
       || parameters->options().user_set_Map()
-      || parameters->target().may_relax())
-    this->input_sections_.push_back(Input_section(object, shndx,
-                                                 shdr.get_sh_size(),
-                                                 addralign));
+      || parameters->target().may_relax()
+      || layout->is_section_ordering_specified())
+    {
+      Input_section isecn(object, shndx, input_section_size, addralign);
+      /* If section ordering is requested by specifying a ordering file,
+        using --section-ordering-file, match the section name with
+        a pattern.  */
+      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();
+            }
+        }
+      if (this->has_fixed_layout())
+       {
+         // For incremental updates, finalize the address and offset now.
+         uint64_t addr = this->address();
+         isecn.set_address_and_file_offset(addr + aligned_offset_in_section,
+                                           aligned_offset_in_section,
+                                           this->offset());
+       }
+      this->input_sections_.push_back(isecn);
+    }
 
   return aligned_offset_in_section;
 }
@@ -1968,27 +2467,71 @@ Output_section::add_output_section_data(Output_section_data* posd)
 
   if (posd->is_data_size_valid())
     {
-      off_t offset_in_section = this->current_data_size_for_child();
-      off_t aligned_offset_in_section = align_address(offset_in_section,
-                                                     posd->addralign());
-      this->set_current_data_size_for_child(aligned_offset_in_section
-                                           + posd->data_size());
+      off_t offset_in_section;
+      if (this->has_fixed_layout())
+       {
+         // For incremental updates, find a chunk of unused space.
+         offset_in_section = this->free_list_.allocate(posd->data_size(),
+                                                       posd->addralign(), 0);
+         if (offset_in_section == -1)
+           gold_fallback(_("out of patch space in section %s; "
+                           "relink with --incremental-full"),
+                         this->name());
+         // Finalize the address and offset now.
+         uint64_t addr = this->address();
+         off_t offset = this->offset();
+         posd->set_address_and_file_offset(addr + offset_in_section,
+                                           offset + offset_in_section);
+       }
+      else
+       {
+         offset_in_section = this->current_data_size_for_child();
+         off_t aligned_offset_in_section = align_address(offset_in_section,
+                                                         posd->addralign());
+         this->set_current_data_size_for_child(aligned_offset_in_section
+                                               + posd->data_size());
+       }
+    }
+  else if (this->has_fixed_layout())
+    {
+      // For incremental updates, arrange for the data to have a fixed layout.
+      // This will mean that additions to the data must be allocated from
+      // free space within the containing output section.
+      uint64_t addr = this->address();
+      posd->set_address(addr);
+      posd->set_file_offset(0);
+      // FIXME: This should eventually be unreachable.
+      // gold_unreachable();
     }
 }
 
 // Add a relaxed input section.
 
 void
-Output_section::add_relaxed_input_section(Output_relaxed_input_section* poris)
+Output_section::add_relaxed_input_section(Layout* layout,
+                                         Output_relaxed_input_section* poris,
+                                         const std::string& name)
 {
   Input_section inp(poris);
-  this->add_output_section_data(&inp);
-  if (this->is_relaxed_input_section_map_valid_)
+
+  // If the --section-ordering-file option is used to specify the order of
+  // sections, we need to keep track of sections.
+  if (layout->is_section_ordering_specified())
     {
-      Input_section_specifier iss(poris->relobj(), poris->shndx());
-      this->relaxed_input_section_map_[iss] = poris;
+      unsigned int section_order_index =
+        layout->find_section_order_index(name);
+      if (section_order_index != 0)
+        {
+          inp.set_section_order_index(section_order_index);
+          this->set_input_section_order_specified();
+        }
     }
 
+  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
@@ -2033,7 +2576,8 @@ 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;
 
@@ -2046,58 +2590,71 @@ Output_section::add_merge_input_section(Relobj* object, unsigned int shndx,
   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);
-  Merge_section_by_properties_map::const_iterator p =
-    this->merge_section_by_properties_map_.find(msp);
-  if (p != this->merge_section_by_properties_map_.end())
-    {
-      Output_merge_base* merge_section = p->second;
-      merge_section->add_input_section(object, shndx);
-      gold_assert(merge_section->is_string() == is_string
-                 && merge_section->entsize() == entsize
-                 && merge_section->addralign() == addralign);
-
-      // Link input section to found merge section.
-      Input_section_specifier iss(object, shndx);
-      this->merge_section_map_[iss] = merge_section;
-      return true;
+  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);
     }
-
-  // We handle the actual constant merging in Output_merge_data or
-  // Output_merge_string_data.
-  Output_merge_base* pomb;
-  if (!is_string)
-    pomb = new Output_merge_data(entsize, addralign);
   else
     {
-      switch (entsize)
+      // Create a new Output_merge_data or Output_merge_string_data.
+      if (!is_string)
+       pomb = new Output_merge_data(entsize, addralign);
+      else
        {
-        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;
+         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;
     }
 
-  // Add new merge section to this output section and link merge section
-  // properties to new merge section in map.
-  this->add_output_merge_section(pomb, is_string, entsize);
-  this->merge_section_by_properties_map_[msp] = pomb;
-
-  // Add input section to new merge section and link input section to new
-  // merge section in map.
-  pomb->add_input_section(object, shndx);
-  Input_section_specifier iss(object, shndx);
-  this->merge_section_map_[iss] = pomb;
+  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);
+       }
 
-  return true;
+      // 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.
@@ -2114,15 +2671,15 @@ Output_section::build_relaxation_map(
       const Input_section& is(input_sections[i]);
       if (is.is_input_section() || is.is_relaxed_input_section())
        {
-         Input_section_specifier iss(is.relobj(), is.shndx());
-         (*relaxation_map)[iss] = i;
+         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 input section
-// specifier to indices of INPUT_SECTIONS.
+// 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(
@@ -2133,11 +2690,17 @@ Output_section::convert_input_sections_in_list_to_relaxed_sections(
   for (size_t i = 0; i < relaxed_sections.size(); ++i)
     {
       Output_relaxed_input_section* poris = relaxed_sections[i];
-      Input_section_specifier iss(poris->relobj(), poris->shndx());
-      Relaxation_map::const_iterator p = map.find(iss);
+      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());
+
+      // Remember section order index of original input section
+      // if it is set.  Copy it to the relaxed input section.
+      unsigned int soi =
+       (*input_sections)[p->second].section_order_index();
       (*input_sections)[p->second] = Input_section(poris);
+      (*input_sections)[p->second].set_section_order_index(soi);
     }
 }
   
@@ -2190,6 +2753,15 @@ Output_section::convert_input_sections_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)
+      {
+       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.
@@ -2233,17 +2805,47 @@ Output_section_data*
 Output_section::find_merge_section(const Relobj* object,
                                   unsigned int shndx) const
 {
-  Input_section_specifier iss(object, shndx);
-  Output_section_data_by_input_section_map::const_iterator p =
-    this->merge_section_map_.find(iss);
-  if (p != this->merge_section_map_.end())
+  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)
     {
-      Output_section_data* posd = p->second;
-      gold_assert(posd->is_merge_section_for(object, shndx));
-      return posd;
+      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())
+       {
+         Output_relaxed_input_section* poris = p->relaxed_input_section();
+         this->lookup_maps_->add_relaxed_input_section(poris->relobj(),
+                                                       poris->shndx(), poris);
+       }
     }
-  else
-    return NULL;
 }
 
 // Find an relaxed input section corresponding to an input section
@@ -2253,31 +2855,9 @@ const Output_relaxed_input_section*
 Output_section::find_relaxed_input_section(const Relobj* object,
                                           unsigned int shndx) const
 {
-  // Be careful that the map may not be valid due to input section export
-  // to scripts or a check-point restore.
-  if (!this->is_relaxed_input_section_map_valid_)
-    {
-      // Rebuild the map as needed.
-      this->relaxed_input_section_map_.clear();
-      for (Input_section_list::const_iterator p = this->input_sections_.begin();
-          p != this->input_sections_.end();
-          ++p)
-       if (p->is_relaxed_input_section())
-         {
-           Input_section_specifier iss(p->relobj(), p->shndx());
-           this->relaxed_input_section_map_[iss] =
-             p->relaxed_input_section();
-         }
-      this->is_relaxed_input_section_map_valid_ = true;
-    }
-
-  Input_section_specifier iss(object, shndx);
-  Output_relaxed_input_section_by_input_section_map::const_iterator p =
-    this->relaxed_input_section_map_.find(iss);
-  if (p != this->relaxed_input_section_map_.end())
-    return p->second;
-  else
-    return NULL;
+  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
@@ -2436,35 +3016,81 @@ Output_section::find_starting_output_address(const Relobj* object,
   return false;
 }
 
-// Set the data size of an Output_section.  This is where we handle
-// setting the addresses of any Output_section_data objects.
+// Update the data size of an Output_section.
 
 void
-Output_section::set_final_data_size()
+Output_section::update_data_size()
 {
   if (this->input_sections_.empty())
-    {
-      this->set_data_size(this->current_data_size_for_child());
       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();
-  off_t startoff = this->offset();
-  off_t off = startoff + this->first_input_offset_;
+  off_t off = this->first_input_offset_;
   for (Input_section_list::iterator p = this->input_sections_.begin();
        p != this->input_sections_.end();
        ++p)
     {
       off = align_address(off, p->addralign());
-      p->set_address_and_file_offset(address + (off - startoff), off,
-                                    startoff);
-      off += p->data_size();
+      off += p->current_data_size();
+    }
+
+  this->set_current_data_size_for_child(off);
+}
+
+// Set the data size of an Output_section.  This is where we handle
+// setting the addresses of any Output_section_data objects.
+
+void
+Output_section::set_final_data_size()
+{
+  off_t data_size;
+
+  if (this->input_sections_.empty())
+    data_size = this->current_data_size_for_child();
+  else
+    {
+      if (this->must_sort_attached_input_sections()
+         || this->input_section_order_specified())
+       this->sort_attached_input_sections();
+
+      uint64_t address = this->address();
+      off_t startoff = this->offset();
+      off_t off = startoff + this->first_input_offset_;
+      for (Input_section_list::iterator p = this->input_sections_.begin();
+          p != this->input_sections_.end();
+          ++p)
+       {
+         off = align_address(off, p->addralign());
+         p->set_address_and_file_offset(address + (off - startoff), off,
+                                        startoff);
+         off += p->data_size();
+       }
+      data_size = off - startoff;
     }
 
-  this->set_data_size(off - startoff);
+  // For full incremental links, we want to allocate some patch space
+  // in most sections for subsequent incremental updates.
+  if (this->is_patch_space_allowed_ && parameters->incremental_full())
+    {
+      double pct = parameters->options().incremental_patch();
+      size_t extra = static_cast<size_t>(data_size * pct);
+      if (this->free_space_fill_ != NULL
+          && this->free_space_fill_->minimum_hole_size() > extra)
+       extra = this->free_space_fill_->minimum_hole_size();
+      off_t new_size = align_address(data_size + extra, this->addralign());
+      this->patch_space_ = new_size - data_size;
+      gold_debug(DEBUG_INCREMENTAL,
+                "set_final_data_size: %08lx + %08lx: section %s",
+                static_cast<long>(data_size),
+                static_cast<long>(this->patch_space_),
+                this->name());
+      data_size = new_size;
+    }
+
+  this->set_data_size(data_size);
 }
 
 // Reset the address and file offset.
@@ -2474,16 +3100,25 @@ 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.
-  if ((this->flags_ & elfcpp::SHF_ALLOC) == 0)
+  // 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();
+
+  // Remove any patch space that was added in set_final_data_size.
+  if (this->patch_space_ > 0)
+    {
+      this->set_current_data_size_for_child(this->current_data_size_for_child()
+                                           - this->patch_space_);
+      this->patch_space_ = 0;
+    }
 }
-  
+
 // Return true if address and file offset have the values after reset.
 
 bool
@@ -2512,7 +3147,7 @@ Output_section::do_set_tls_offset(uint64_t tls_base)
 // priority ordering implemented by the GNU linker, in which the
 // priority becomes part of the section name and the sections are
 // sorted by name.  We only do this for an output section if we see an
-// attached input section matching ".ctor.*", ".dtor.*",
+// attached input section matching ".ctors.*", ".dtors.*",
 // ".init_array.*" or ".fini_array.*".
 
 class Output_section::Input_section_sort_entry
@@ -2524,12 +3159,14 @@ 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()
                        || 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
@@ -2582,7 +3219,35 @@ 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 the priority.  Believe it or not, gcc encodes the priority
+  // differently for .ctors/.dtors and .init_array/.fini_array
+  // sections.
+  unsigned int
+  get_priority() const
+  {
+    gold_assert(this->section_has_name_);
+    bool is_ctors;
+    if (is_prefix_of(".ctors.", this->section_name_.c_str())
+       || is_prefix_of(".dtors.", this->section_name_.c_str()))
+      is_ctors = true;
+    else if (is_prefix_of(".init_array.", this->section_name_.c_str())
+            || is_prefix_of(".fini_array.", this->section_name_.c_str()))
+      is_ctors = false;
+    else
+      return 0;
+    char* end;
+    unsigned long prio = strtoul((this->section_name_.c_str()
+                                 + (is_ctors ? 7 : 12)),
+                                &end, 10);
+    if (*end != '\0')
+      return 0;
+    else if (is_ctors)
+      return 65535 - prio;
+    else
+      return prio;
   }
 
   // Return true if this an input file whose base name matches
@@ -2593,17 +3258,24 @@ class Output_section::Input_section_sort_entry
   // file name this way is a dreadful hack, but the GNU linker does it
   // in order to better support gcc, and we need to be compatible.
   bool
-  match_file_name(const char* match_file_name) const
+  match_file_name(const char* file_name) const
+  { return Layout::match_file_name(this->input_section_.relobj(), file_name); }
+
+  // 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
   {
-    const std::string& file_name(this->input_section_.relobj()->name());
-    const char* base_name = lbasename(file_name.c_str());
-    size_t match_len = strlen(match_file_name);
-    if (strncmp(base_name, match_file_name, match_len) != 0)
-      return false;
-    size_t base_len = strlen(base_name);
-    if (base_len != match_len + 2 && base_len != match_len + 3)
-      return false;
-    return memcmp(base_name + base_len - 2, ".o", 2) == 0;
+    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:
@@ -2660,8 +3332,6 @@ 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)
@@ -2669,6 +3339,12 @@ 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)
@@ -2678,35 +3354,167 @@ Output_section::Input_section_sort_compare::operator()(
   return s1.index() < s2.index();
 }
 
-// Sort the input sections attached to an output section.
+// Return true if S1 should come before S2 in an .init_array or .fini_array
+// output section.
 
-void
-Output_section::sort_attached_input_sections()
+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
 {
-  if (this->attached_input_sections_are_sorted_)
-    return;
+  // 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();
+    }
 
-  if (this->checkpoint_ != NULL
-      && !this->checkpoint_->input_sections_saved())
-    this->checkpoint_->save_input_sections();
+  // 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;
 
-  // 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
-  // problem we can cache the names as required in Layout::layout.
+  // .ctors and .dtors sections without priority come after
+  // .init_array and .fini_array sections without priority.
+  if (!s1_has_priority
+      && (s1.section_name() == ".ctors" || s1.section_name() == ".dtors")
+      && s1.section_name() != s2.section_name())
+    return false;
+  if (!s2_has_priority
+      && (s2.section_name() == ".ctors" || s2.section_name() == ".dtors")
+      && s2.section_name() != s1.section_name())
+    return true;
 
-  // We start by building a larger vector holding a copy of each
-  // Input_section, plus its current index in the list and its name.
-  std::vector<Input_section_sort_entry> sort_list;
+  // Sort by priority if we can.
+  if (s1_has_priority)
+    {
+      unsigned int s1_prio = s1.get_priority();
+      unsigned int s2_prio = s2.get_priority();
+      if (s1_prio < s2_prio)
+       return true;
+      else if (s1_prio > s2_prio)
+       return false;
+    }
 
-  unsigned int i = 0;
-  for (Input_section_list::iterator p = this->input_sections_.begin();
+  // 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;
+}
+
+// This updates the section order index of input sections according to the
+// the order specified in the mapping from Section id to order index.
+
+void
+Output_section::update_section_layout(
+  const Section_layout_order* order_map)
+{
+  for (Input_section_list::iterator p = this->input_sections_.begin();
+       p != this->input_sections_.end();
+       ++p)
+    {
+      if (p->is_input_section()
+         || p->is_relaxed_input_section())
+        {
+         Object* obj = (p->is_input_section()
+                        ? p->relobj()
+                        : p->relaxed_input_section()->relobj());
+         unsigned int shndx = p->shndx();
+         Section_layout_order::const_iterator it
+           = order_map->find(Section_id(obj, shndx));
+         if (it == order_map->end())
+           continue;
+         unsigned int section_order_index = it->second;
+         if (section_order_index != 0)
+            {
+              p->set_section_order_index(section_order_index);
+              this->set_input_section_order_specified();
+           }
+        }
+    }
+}
+
+// Sort the input sections attached to an output section.
+
+void
+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
+  // problem we can cache the names as required in Layout::layout.
+
+  // We start by building a larger vector holding a copy of each
+  // Input_section, plus its current index in the list and its name.
+  std::vector<Input_section_sort_entry> sort_list;
+
+  unsigned int i = 0;
+  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(this->input_section_order_specified());
+      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();
@@ -2714,6 +3522,7 @@ 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.
@@ -2742,7 +3551,7 @@ Output_section::write_header(const Layout* layout,
   if (this->link_section_ != NULL)
     oshdr->put_sh_link(this->link_section_->out_shndx());
   else if (this->should_link_to_symtab_)
-    oshdr->put_sh_link(layout->symtab_section()->out_shndx());
+    oshdr->put_sh_link(layout->symtab_section_shndx());
   else if (this->should_link_to_dynsym_)
     oshdr->put_sh_link(layout->dynsym_section()->out_shndx());
   else
@@ -2804,6 +3613,26 @@ Output_section::do_write(Output_file* of)
       p->write(of);
       off = aligned_off + p->data_size();
     }
+
+  // For incremental links, fill in unused chunks in debug sections
+  // with dummy compilation unit headers.
+  if (this->free_space_fill_ != NULL)
+    {
+      for (Free_list::Const_iterator p = this->free_list_.begin();
+          p != this->free_list_.end();
+          ++p)
+       {
+         off_t off = p->start_;
+         size_t len = p->end_ - off;
+         this->free_space_fill_->write(of, this->offset() + off, len);
+       }
+      if (this->patch_space_ > 0)
+       {
+         off_t off = this->current_data_size_for_child() - this->patch_space_;
+         this->free_space_fill_->write(of, this->offset() + off,
+                                       this->patch_space_);
+       }
+    }
 }
 
 // If a section requires postprocessing, create the buffer to use.
@@ -2889,14 +3718,14 @@ uint64_t
 Output_section::get_input_sections(
     uint64_t address,
     const std::string& fill,
-    std::list<Simple_input_section>* input_sections)
+    std::list<Input_section>* input_sections)
 {
   if (this->checkpoint_ != NULL
       && !this->checkpoint_->input_sections_saved())
     this->checkpoint_->save_input_sections();
 
-  // Invalidate the relaxed input section map.
-  this->is_relaxed_input_section_map_valid_ = false;
+  // Invalidate fast look-up maps.
+  this->lookup_maps_->invalidate();
 
   uint64_t orig_address = address;
 
@@ -2907,12 +3736,10 @@ Output_section::get_input_sections(
        p != this->input_sections_.end();
        ++p)
     {
-      if (p->is_input_section())
-       input_sections->push_back(Simple_input_section(p->relobj(),
-                                                      p->shndx()));
-      else if (p->is_relaxed_input_section())
-       input_sections->push_back(
-           Simple_input_section(p->relaxed_input_section()));
+      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());
@@ -2947,13 +3774,16 @@ 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(const Simple_input_section& sis,
-                                            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;
 
@@ -2964,14 +3794,34 @@ Output_section::add_input_section_for_script(const Simple_input_section& sis,
   this->set_current_data_size_for_child(aligned_offset_in_section
                                        + data_size);
 
-  Input_section is =
-    (sis.is_relaxed_input_section()
-     ? Input_section(sis.relaxed_input_section())
-     : Input_section(sis.relobj(), sis.shndx(), data_size, addralign));
-  this->input_sections_.push_back(is);
+  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()
@@ -2986,6 +3836,19 @@ Output_section::save_states()
   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()
 {
@@ -3015,9 +3878,32 @@ Output_section::restore_states()
   this->attached_input_sections_are_sorted_ =
     checkpoint->attached_input_sections_are_sorted();
 
-  // Simply invalidate the relaxed input section map since we do not keep
-  // track of it.
-  this->is_relaxed_input_section_map_valid_ = false;
+  // 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.
@@ -3045,12 +3931,44 @@ Output_section::print_merge_stats()
     p->print_merge_stats(this->name_);
 }
 
+// Set a fixed layout for the section.  Used for incremental update links.
+
+void
+Output_section::set_fixed_layout(uint64_t sh_addr, off_t sh_offset,
+                                off_t sh_size, uint64_t sh_addralign)
+{
+  this->addralign_ = sh_addralign;
+  this->set_current_data_size(sh_size);
+  if ((this->flags_ & elfcpp::SHF_ALLOC) != 0)
+    this->set_address(sh_addr);
+  this->set_file_offset(sh_offset);
+  this->finalize_data_size();
+  this->free_list_.init(sh_size, false);
+  this->has_fixed_layout_ = true;
+}
+
+// Reserve space within the fixed layout for the section.  Used for
+// incremental update links.
+
+void
+Output_section::reserve(uint64_t sh_offset, uint64_t sh_size)
+{
+  this->free_list_.remove(sh_offset, sh_offset + sh_size);
+}
+
+// Allocate space from the free list for the section.  Used for
+// incremental update links.
+
+off_t
+Output_section::allocate(off_t len, uint64_t addralign)
+{
+  return this->free_list_.allocate(len, addralign, 0);
+}
+
 // Output segment methods.
 
 Output_segment::Output_segment(elfcpp::Elf_Word type, elfcpp::Elf_Word flags)
-  : output_data_(),
-    output_bss_(),
-    vaddr_(0),
+  : vaddr_(0),
     paddr_(0),
     memsz_(0),
     max_align_(0),
@@ -3069,293 +3987,64 @@ Output_segment::Output_segment(elfcpp::Elf_Word type, elfcpp::Elf_Word flags)
     this->flags_ = elfcpp::PF_R;
 }
 
-// Add an Output_section to an Output_segment.
+// Add an Output_section to a PT_LOAD Output_segment.
 
 void
-Output_segment::add_output_section(Output_section* os,
-                                  elfcpp::Elf_Word seg_flags,
-                                  bool do_sort)
+Output_segment::add_output_section_to_load(Layout* layout,
+                                          Output_section* os,
+                                          elfcpp::Elf_Word seg_flags)
 {
+  gold_assert(this->type() == elfcpp::PT_LOAD);
   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);
 
   this->update_flags_for_output_section(seg_flags);
 
-  Output_segment::Output_data_list* pdl;
-  if (os->type() == elfcpp::SHT_NOBITS)
-    pdl = &this->output_bss_;
+  // We don't want to change the ordering if we have a linker script
+  // with a SECTIONS clause.
+  Output_section_order order = os->order();
+  if (layout->script_options()->saw_sections_clause())
+    order = static_cast<Output_section_order>(0);
   else
-    pdl = &this->output_data_;
+    gold_assert(order != ORDER_INVALID);
 
-  // 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.  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();
-      do
-       {
-         --p;
-         if ((*p)->is_section_type(elfcpp::SHT_NOTE))
-           {
-             ++p;
-             pdl->insert(p, os);
-             return;
-           }
-       }
-      while (p != pdl->begin());
-    }
-
-  // Similarly, so that PT_TLS segments will work, we need to group
-  // SHF_TLS sections.  An SHF_TLS/SHT_NOBITS section is a special
-  // 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.
-  if (this->type_ != elfcpp::PT_TLS
-      && (os->flags() & elfcpp::SHF_TLS) != 0)
-    {
-      pdl = &this->output_data_;
-      if (!pdl->empty())
-       {
-         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
-           {
-             --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;
-               }
-           }
-         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 (!(*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;
-           }
-
-         pdl->insert(p, os);
-         return;
-       }
+  this->output_lists_[order].push_back(os);
+}
 
-      // 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;
+// Add an Output_section to a non-PT_LOAD Output_segment.
 
-             Output_section* pos = (*p)->output_section();
-             if (!pos->is_relro())
-               break;
-           }
+void
+Output_segment::add_output_section_to_nonload(Output_section* os,
+                                             elfcpp::Elf_Word seg_flags)
+{
+  gold_assert(this->type() != elfcpp::PT_LOAD);
+  gold_assert((os->flags() & elfcpp::SHF_ALLOC) != 0);
+  gold_assert(!this->is_max_align_known_);
 
-         pdl->insert(p, os);
-         return;
-       }
-    }
+  this->update_flags_for_output_section(seg_flags);
 
-  // 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())
-           {
-             pdl->insert(p, os);
-             return;
-           }
-       }
-      gold_unreachable();
-    }
+  this->output_lists_[0].push_back(os);
+}
 
-  // 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;
-           }
-       }
-    }
+// Remove an Output_section from this segment.  It is an error if it
+// is not present.
 
-  // 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())
+void
+Output_segment::remove_output_section(Output_section* os)
+{
+  for (int i = 0; i < static_cast<int>(ORDER_MAX); ++i)
     {
-      for (Output_segment::Output_data_list::iterator p = pdl->begin();
-          p != pdl->end();
-          ++p)
+      Output_data_list* pdl = &this->output_lists_[i];
+      for (Output_data_list::iterator p = pdl->begin(); p != pdl->end(); ++p)
        {
-         if ((*p)->is_section()
-             && (*p)->output_section()->is_large_section())
+         if (*p == os)
            {
-             pdl->insert(p, os);
+             pdl->erase(p);
              return;
            }
        }
-      gold_unreachable();
-    }
-
-  // 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;
-       }
-
-      // 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);
-}
-
-// Remove an Output_section from this segment.  It is an error if it
-// is not present.
-
-void
-Output_segment::remove_output_section(Output_section* os)
-{
-  // We only need this for SHT_PROGBITS.
-  gold_assert(os->type() == elfcpp::SHT_PROGBITS);
-  for (Output_data_list::iterator p = this->output_data_.begin();
-       p != this->output_data_.end();
-       ++p)
-   {
-     if (*p == os)
-       {
-         this->output_data_.erase(p);
-         return;
-       }
-   }
   gold_unreachable();
 }
 
@@ -3366,17 +4055,51 @@ void
 Output_segment::add_initial_output_data(Output_data* od)
 {
   gold_assert(!this->is_max_align_known_);
-  this->output_data_.push_front(od);
+  Output_data_list::iterator p = this->output_lists_[0].begin();
+  this->output_lists_[0].insert(p, od);
+}
+
+// Return true if this segment has any sections which hold actual
+// data, rather than being a BSS section.
+
+bool
+Output_segment::has_any_data_sections() const
+{
+  for (int i = 0; i < static_cast<int>(ORDER_MAX); ++i)
+    {
+      const Output_data_list* pdl = &this->output_lists_[i];
+      for (Output_data_list::const_iterator p = pdl->begin();
+          p != pdl->end();
+          ++p)
+       {
+         if (!(*p)->is_section())
+           return true;
+         if ((*p)->output_section()->type() != elfcpp::SHT_NOBITS)
+           return true;
+       }
+    }
+  return false;
 }
 
-// Return whether the first data section is a relro section.
+// Return whether the first data section (not counting TLS sections)
+// is a relro section.
 
 bool
 Output_segment::is_first_section_relro() const
 {
-  return (!this->output_data_.empty()
-         && this->output_data_.front()->is_section()
-         && this->output_data_.front()->output_section()->is_relro());
+  for (int i = 0; i < static_cast<int>(ORDER_MAX); ++i)
+    {
+      if (i == static_cast<int>(ORDER_TLS_DATA)
+         || i == static_cast<int>(ORDER_TLS_BSS))
+       continue;
+      const Output_data_list* pdl = &this->output_lists_[i];
+      if (!pdl->empty())
+       {
+         Output_data* p = pdl->front();
+         return p->is_section() && p->output_section()->is_relro();
+       }
+    }
+  return false;
 }
 
 // Return the maximum alignment of the Output_data in Output_segment.
@@ -3386,16 +4109,13 @@ Output_segment::maximum_alignment()
 {
   if (!this->is_max_align_known_)
     {
-      uint64_t addralign;
-
-      addralign = Output_segment::maximum_alignment_list(&this->output_data_);
-      if (addralign > this->max_align_)
-       this->max_align_ = addralign;
-
-      addralign = Output_segment::maximum_alignment_list(&this->output_bss_);
-      if (addralign > this->max_align_)
-       this->max_align_ = addralign;
-
+      for (int i = 0; i < static_cast<int>(ORDER_MAX); ++i)
+       {       
+         const Output_data_list* pdl = &this->output_lists_[i];
+         uint64_t addralign = Output_segment::maximum_alignment_list(pdl);
+         if (addralign > this->max_align_)
+           this->max_align_ = addralign;
+       }
       this->is_max_align_known_ = true;
     }
 
@@ -3419,45 +4139,55 @@ Output_segment::maximum_alignment_list(const Output_data_list* pdl)
   return ret;
 }
 
-// Return the number of dynamic relocs applied to this segment.
+// Return whether this segment has any dynamic relocs.
 
-unsigned int
-Output_segment::dynamic_reloc_count() const
+bool
+Output_segment::has_dynamic_reloc() const
 {
-  return (this->dynamic_reloc_count_list(&this->output_data_)
-         + this->dynamic_reloc_count_list(&this->output_bss_));
+  for (int i = 0; i < static_cast<int>(ORDER_MAX); ++i)
+    if (this->has_dynamic_reloc_list(&this->output_lists_[i]))
+      return true;
+  return false;
 }
 
-// Return the number of dynamic relocs applied to an Output_data_list.
+// Return whether this Output_data_list has any dynamic relocs.
 
-unsigned int
-Output_segment::dynamic_reloc_count_list(const Output_data_list* pdl) const
+bool
+Output_segment::has_dynamic_reloc_list(const Output_data_list* pdl) const
 {
-  unsigned int count = 0;
   for (Output_data_list::const_iterator p = pdl->begin();
        p != pdl->end();
        ++p)
-    count += (*p)->dynamic_reloc_count();
-  return count;
+    if ((*p)->has_dynamic_reloc())
+      return true;
+  return false;
 }
 
 // Set the section addresses for an Output_segment.  If RESET is true,
 // reset the addresses first.  ADDR is the address and *POFF is the
 // file offset.  Set the section indexes starting with *PSHNDX.
-// Return the address of the immediately following segment.  Update
-// *POFF and *PSHNDX.
+// INCREASE_RELRO is the size of the portion of the first non-relro
+// section that should be included in the PT_GNU_RELRO segment.
+// If this segment has relro sections, and has been aligned for
+// that purpose, set *HAS_RELRO to TRUE.  Return the address of
+// the immediately following segment.  Update *HAS_RELRO, *POFF,
+// and *PSHNDX.
 
 uint64_t
-Output_segment::set_section_addresses(const Layout* layout, bool reset,
+Output_segment::set_section_addresses(Layout* layout, bool reset,
                                       uint64_t addr,
-                                     unsigned int increase_relro,
+                                     unsigned int* increase_relro,
+                                     bool* has_relro,
                                      off_t* poff,
                                      unsigned int* pshndx)
 {
   gold_assert(this->type_ == elfcpp::PT_LOAD);
 
+  uint64_t last_relro_pad = 0;
   off_t orig_off = *poff;
 
+  bool in_tls = false;
+
   // 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()
@@ -3466,33 +4196,58 @@ Output_segment::set_section_addresses(const Layout* layout, bool 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)
+      uint64_t max_align = 0;
+      for (int i = 0; i <= static_cast<int>(ORDER_RELRO_LAST); ++i)
        {
-         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
+         Output_data_list* pdl = &this->output_lists_[i];
+         Output_data_list::iterator p;
+         for (p = pdl->begin(); p != pdl->end(); ++p)
            {
-             // 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();
+             if (!(*p)->is_section())
+               break;
+             uint64_t align = (*p)->addralign();
+             if (align > max_align)
+               max_align = align;
+             if ((*p)->is_section_flag_set(elfcpp::SHF_TLS))
+               in_tls = true;
+             else if (in_tls)
+               {
+                 // Align the first non-TLS section to the alignment
+                 // of the TLS segment.
+                 align = max_align;
+                 in_tls = false;
+               }
+             relro_size = align_address(relro_size, align);
+             // Ignore the size of the .tbss section.
+             if ((*p)->is_section_flag_set(elfcpp::SHF_TLS)
+                 && (*p)->is_section_type(elfcpp::SHT_NOBITS))
+               continue;
+             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();
+               }
            }
+         if (p != pdl->end())
+           break;
        }
-      relro_size += increase_relro;
+      relro_size += *increase_relro;
+      // Pad the total relro size to a multiple of the maximum
+      // section alignment seen.
+      uint64_t aligned_size = align_address(relro_size, max_align);
+      // Note the amount of padding added after the last relro section.
+      last_relro_pad = aligned_size - relro_size;
+      *has_relro = true;
 
       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);
+      uint64_t desired_align = page_align - (aligned_size % page_align);
       if (desired_align < *poff % page_align)
        *poff += page_align - *poff % page_align;
       *poff += desired_align - *poff % page_align;
@@ -3512,20 +4267,37 @@ Output_segment::set_section_addresses(const Layout* layout, bool reset,
       this->are_addresses_set_ = true;
     }
 
-  bool in_tls = false;
+  in_tls = false;
 
   this->offset_ = orig_off;
 
-  addr = this->set_section_list_addresses(layout, reset, &this->output_data_,
-                                         addr, poff, pshndx, &in_tls);
-  this->filesz_ = *poff - orig_off;
-
-  off_t off = *poff;
+  off_t off = 0;
+  uint64_t ret;
+  for (int i = 0; i < static_cast<int>(ORDER_MAX); ++i)
+    {
+      if (i == static_cast<int>(ORDER_RELRO_LAST))
+       {
+         *poff += last_relro_pad;
+         addr += last_relro_pad;
+         if (this->output_lists_[i].empty())
+           {
+             // If there is nothing in the ORDER_RELRO_LAST list,
+             // the padding will occur at the end of the relro
+             // segment, and we need to add it to *INCREASE_RELRO.
+             *increase_relro += last_relro_pad;
+           }
+       }
+      addr = this->set_section_list_addresses(layout, reset,
+                                             &this->output_lists_[i],
+                                             addr, poff, pshndx, &in_tls);
+      if (i < static_cast<int>(ORDER_SMALL_BSS))
+       {
+         this->filesz_ = *poff - orig_off;
+         off = *poff;
+       }
 
-  uint64_t ret = this->set_section_list_addresses(layout, reset,
-                                                  &this->output_bss_,
-                                                 addr, poff, pshndx,
-                                                  &in_tls);
+      ret = addr;
+    }
 
   // 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
@@ -3549,13 +4321,16 @@ Output_segment::set_section_addresses(const Layout* layout, bool reset,
 // structures.
 
 uint64_t
-Output_segment::set_section_list_addresses(const Layout* layout, bool reset,
+Output_segment::set_section_list_addresses(Layout* layout, bool reset,
                                            Output_data_list* pdl,
                                           uint64_t addr, off_t* poff,
                                           unsigned int* pshndx,
                                            bool* in_tls)
 {
   off_t startoff = *poff;
+  // For incremental updates, we may allocate non-fixed sections from
+  // free space in the file.  This keeps track of the high-water mark.
+  off_t maxoff = startoff;
 
   off_t off = startoff;
   for (Output_data_list::iterator p = pdl->begin();
@@ -3565,8 +4340,8 @@ Output_segment::set_section_list_addresses(const Layout* layout, bool reset,
       if (reset)
        (*p)->reset_address_and_file_offset();
 
-      // When using a linker script the section will most likely
-      // already have an address.
+      // When doing an incremental update or when using a linker script,
+      // the section will most likely already have an address.
       if (!(*p)->is_address_valid())
        {
           uint64_t align = (*p)->addralign();
@@ -3604,9 +4379,40 @@ Output_segment::set_section_list_addresses(const Layout* layout, bool reset,
                 }
             }
 
-         off = align_address(off, align);
-         (*p)->set_address_and_file_offset(addr + (off - startoff), off);
+         if (!parameters->incremental_update())
+           {
+             off = align_address(off, align);
+             (*p)->set_address_and_file_offset(addr + (off - startoff), off);
+           }
+         else
+           {
+             // Incremental update: allocate file space from free list.
+             (*p)->pre_finalize_data_size();
+             off_t current_size = (*p)->current_data_size();
+             off = layout->allocate(current_size, align, startoff);
+             if (off == -1)
+               {
+                 gold_assert((*p)->output_section() != NULL);
+                 gold_fallback(_("out of patch space for section %s; "
+                                 "relink with --incremental-full"),
+                               (*p)->output_section()->name());
+               }
+             (*p)->set_address_and_file_offset(addr + (off - startoff), off);
+             if ((*p)->data_size() > current_size)
+               {
+                 gold_assert((*p)->output_section() != NULL);
+                 gold_fallback(_("%s: section changed size; "
+                                 "relink with --incremental-full"),
+                               (*p)->output_section()->name());
+               }
+           }
        }
+      else if (parameters->incremental_update())
+        {
+          // For incremental updates, use the fixed offset for the
+          // high-water mark computation.
+          off = (*p)->offset();
+        }
       else
        {
          // The script may have inserted a skip forward, but it
@@ -3640,13 +4446,24 @@ Output_segment::set_section_list_addresses(const Layout* layout, bool reset,
          (*p)->finalize_data_size();
        }
 
-      // We want to ignore the size of a SHF_TLS or SHT_NOBITS
+      if (parameters->incremental_update())
+       gold_debug(DEBUG_INCREMENTAL,
+                  "set_section_list_addresses: %08lx %08lx %s",
+                  static_cast<long>(off),
+                  static_cast<long>((*p)->data_size()),
+                  ((*p)->output_section() != NULL
+                   ? (*p)->output_section()->name() : "(special)"));
+
+      // We want to ignore the size of a SHF_TLS SHT_NOBITS
       // section.  Such a section does not affect the size of a
       // PT_LOAD segment.
       if (!(*p)->is_section_flag_set(elfcpp::SHF_TLS)
          || !(*p)->is_section_type(elfcpp::SHT_NOBITS))
        off += (*p)->data_size();
 
+      if (off > maxoff)
+        maxoff = off;
+
       if ((*p)->is_section())
        {
          (*p)->set_out_shndx(*pshndx);
@@ -3654,8 +4471,8 @@ Output_segment::set_section_list_addresses(const Layout* layout, bool reset,
        }
     }
 
-  *poff = off;
-  return addr + (off - startoff);
+  *poff = maxoff;
+  return addr + (maxoff - startoff);
 }
 
 // For a non-PT_LOAD segment, set the offset from the sections, if
@@ -3668,7 +4485,11 @@ Output_segment::set_offset(unsigned int increase)
 
   gold_assert(!this->are_addresses_set_);
 
-  if (this->output_data_.empty() && this->output_bss_.empty())
+  // A non-load section only uses output_lists_[0].
+
+  Output_data_list* pdl = &this->output_lists_[0];
+
+  if (pdl->empty())
     {
       gold_assert(increase == 0);
       this->vaddr_ = 0;
@@ -3681,11 +4502,32 @@ Output_segment::set_offset(unsigned int increase)
       return;
     }
 
-  const Output_data* first;
-  if (this->output_data_.empty())
-    first = this->output_bss_.front();
-  else
-    first = this->output_data_.front();
+  // Find the first and last section by address.
+  const Output_data* first = NULL;
+  const Output_data* last_data = NULL;
+  const Output_data* last_bss = NULL;
+  for (Output_data_list::const_iterator p = pdl->begin();
+       p != pdl->end();
+       ++p)
+    {
+      if (first == NULL
+         || (*p)->address() < first->address()
+         || ((*p)->address() == first->address()
+             && (*p)->data_size() < first->data_size()))
+       first = *p;
+      const Output_data** plast;
+      if ((*p)->is_section()
+         && (*p)->output_section()->type() == elfcpp::SHT_NOBITS)
+       plast = &last_bss;
+      else
+       plast = &last_data;
+      if (*plast == NULL
+         || (*p)->address() > (*plast)->address()
+         || ((*p)->address() == (*plast)->address()
+             && (*p)->data_size() > (*plast)->data_size()))
+       *plast = *p;
+    }
+
   this->vaddr_ = first->address();
   this->paddr_ = (first->has_load_address()
                  ? first->load_address()
@@ -3693,21 +4535,14 @@ Output_segment::set_offset(unsigned int increase)
   this->are_addresses_set_ = true;
   this->offset_ = first->offset();
 
-  if (this->output_data_.empty())
+  if (last_data == NULL)
     this->filesz_ = 0;
   else
-    {
-      const Output_data* last_data = this->output_data_.back();
-      this->filesz_ = (last_data->address()
-                      + last_data->data_size()
-                      - this->vaddr_);
-    }
+    this->filesz_ = (last_data->address()
+                    + last_data->data_size()
+                    - this->vaddr_);
 
-  const Output_data* last;
-  if (this->output_bss_.empty())
-    last = this->output_data_.back();
-  else
-    last = this->output_bss_.back();
+  const Output_data* last = last_bss != NULL ? last_bss : last_data;
   this->memsz_ = (last->address()
                  + last->data_size()
                  - this->vaddr_);
@@ -3715,6 +4550,23 @@ Output_segment::set_offset(unsigned int increase)
   this->filesz_ += increase;
   this->memsz_ += increase;
 
+  // If this is a RELRO segment, verify that the segment ends at a
+  // page boundary.
+  if (this->type_ == elfcpp::PT_GNU_RELRO)
+    {
+      uint64_t page_align = parameters->target().common_pagesize();
+      uint64_t segment_end = this->vaddr_ + this->memsz_;
+      if (parameters->incremental_update())
+       {
+         // The INCREASE_RELRO calculation is bypassed for an incremental
+         // update, so we need to adjust the segment size manually here.
+         segment_end = align_address(segment_end, page_align);
+         this->memsz_ = segment_end - this->vaddr_;
+       }
+      else
+       gold_assert(segment_end == align_address(segment_end, page_align));
+    }
+
   // 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.
@@ -3733,34 +4585,30 @@ Output_segment::set_tls_offsets()
 {
   gold_assert(this->type_ == elfcpp::PT_TLS);
 
-  for (Output_data_list::iterator p = this->output_data_.begin();
-       p != this->output_data_.end();
-       ++p)
-    (*p)->set_tls_offset(this->vaddr_);
-
-  for (Output_data_list::iterator p = this->output_bss_.begin();
-       p != this->output_bss_.end();
+  for (Output_data_list::iterator p = this->output_lists_[0].begin();
+       p != this->output_lists_[0].end();
        ++p)
     (*p)->set_tls_offset(this->vaddr_);
 }
 
-// Return the address of the first section.
+// Return the load address of the first section.
 
 uint64_t
 Output_segment::first_section_load_address() const
 {
-  for (Output_data_list::const_iterator p = this->output_data_.begin();
-       p != this->output_data_.end();
-       ++p)
-    if ((*p)->is_section())
-      return (*p)->has_load_address() ? (*p)->load_address() : (*p)->address();
-
-  for (Output_data_list::const_iterator p = this->output_bss_.begin();
-       p != this->output_bss_.end();
-       ++p)
-    if ((*p)->is_section())
-      return (*p)->has_load_address() ? (*p)->load_address() : (*p)->address();
-
+  for (int i = 0; i < static_cast<int>(ORDER_MAX); ++i)
+    {
+      const Output_data_list* pdl = &this->output_lists_[i];
+      for (Output_data_list::const_iterator p = pdl->begin();
+          p != pdl->end();
+          ++p)
+       {
+         if ((*p)->is_section())
+           return ((*p)->has_load_address()
+                   ? (*p)->load_address()
+                   : (*p)->address());
+       }
+    }
   gold_unreachable();
 }
 
@@ -3769,8 +4617,10 @@ Output_segment::first_section_load_address() const
 unsigned int
 Output_segment::output_section_count() const
 {
-  return (this->output_section_count_list(&this->output_data_)
-         + this->output_section_count_list(&this->output_bss_));
+  unsigned int ret = 0;
+  for (int i = 0; i < static_cast<int>(ORDER_MAX); ++i)
+    ret += this->output_section_count_list(&this->output_lists_[i]);
+  return ret;
 }
 
 // Return the number of Output_sections in an Output_data_list.
@@ -3798,18 +4648,9 @@ Output_segment::section_with_lowest_load_address() const
 {
   Output_section* found = NULL;
   uint64_t found_lma = 0;
-  this->lowest_load_address_in_list(&this->output_data_, &found, &found_lma);
-
-  Output_section* found_data = found;
-  this->lowest_load_address_in_list(&this->output_bss_, &found, &found_lma);
-  if (found != found_data && found_data != NULL)
-    {
-      gold_error(_("nobits section %s may not precede progbits section %s "
-                  "in same segment"),
-                found->name(), found_data->name());
-      return NULL;
-    }
-
+  for (int i = 0; i < static_cast<int>(ORDER_MAX); ++i)
+    this->lowest_load_address_in_list(&this->output_lists_[i], &found,
+                                     &found_lma);
   return found;
 }
 
@@ -3861,7 +4702,7 @@ unsigned char*
 Output_segment::write_section_headers(const Layout* layout,
                                      const Stringpool* secnamepool,
                                      unsigned char* v,
-                                     unsigned int *pshndx) const
+                                     unsigned intpshndx) const
 {
   // Every section that is attached to a segment must be attached to a
   // PT_LOAD segment, so we only write out section headers for PT_LOAD
@@ -3869,12 +4710,15 @@ Output_segment::write_section_headers(const Layout* layout,
   if (this->type_ != elfcpp::PT_LOAD)
     return v;
 
-  v = this->write_section_headers_list<size, big_endian>(layout, secnamepool,
-                                                        &this->output_data_,
-                                                        v, pshndx);
-  v = this->write_section_headers_list<size, big_endian>(layout, secnamepool,
-                                                        &this->output_bss_,
-                                                        v, pshndx);
+  for (int i = 0; i < static_cast<int>(ORDER_MAX); ++i)
+    {
+      const Output_data_list* pdl = &this->output_lists_[i];
+      v = this->write_section_headers_list<size, big_endian>(layout,
+                                                            secnamepool,
+                                                            pdl,
+                                                            v, pshndx);
+    }
+
   return v;
 }
 
@@ -3911,8 +4755,8 @@ Output_segment::print_sections_to_mapfile(Mapfile* mapfile) const
 {
   if (this->type() != elfcpp::PT_LOAD)
     return;
-  this->print_section_list_to_mapfile(mapfile, &this->output_data_);
-  this->print_section_list_to_mapfile(mapfile, &this->output_bss_);
+  for (int i = 0; i < static_cast<int>(ORDER_MAX); ++i)
+    this->print_section_list_to_mapfile(mapfile, &this->output_lists_[i]);
 }
 
 // Print an output section list to the map file.
@@ -3935,36 +4779,93 @@ Output_file::Output_file(const char* name)
     file_size_(0),
     base_(NULL),
     map_is_anonymous_(false),
+    map_is_allocated_(false),
     is_temporary_(false)
 {
 }
 
 // Try to open an existing file.  Returns false if the file doesn't
-// exist, has a size of 0 or can't be mmapped.
+// exist, has a size of 0 or can't be mmapped.  If BASE_NAME is not
+// NULL, open that file as the base for incremental linking, and
+// copy its contents to the new output file.  This routine can
+// be called for incremental updates, in which case WRITABLE should
+// be true, or by the incremental-dump utility, in which case
+// WRITABLE should be false.
 
 bool
-Output_file::open_for_modification()
+Output_file::open_base_file(const char* base_name, bool writable)
 {
   // The name "-" means "stdout".
   if (strcmp(this->name_, "-") == 0)
     return false;
 
+  bool use_base_file = base_name != NULL;
+  if (!use_base_file)
+    base_name = this->name_;
+  else if (strcmp(base_name, this->name_) == 0)
+    gold_fatal(_("%s: incremental base and output file name are the same"),
+              base_name);
+
   // 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;
+  if (::stat(base_name, &s) != 0)
+    {
+      gold_info(_("%s: stat: %s"), base_name, strerror(errno));
+      return false;
+    }
+  if (s.st_size == 0)
+    {
+      gold_info(_("%s: incremental base file is empty"), base_name);
+      return false;
+    }
 
-  int o = open_descriptor(-1, this->name_, O_RDWR, 0);
+  // If we're using a base file, we want to open it read-only.
+  if (use_base_file)
+    writable = false;
+
+  int oflags = writable ? O_RDWR : O_RDONLY;
+  int o = open_descriptor(-1, base_name, oflags, 0);
   if (o < 0)
-    gold_fatal(_("%s: open: %s"), this->name_, strerror(errno));
+    {
+      gold_info(_("%s: open: %s"), base_name, strerror(errno));
+      return false;
+    }
+
+  // If the base file and the output file are different, open a
+  // new output file and read the contents from the base file into
+  // the newly-mapped region.
+  if (use_base_file)
+    {
+      this->open(s.st_size);
+      ssize_t bytes_to_read = s.st_size;
+      unsigned char* p = this->base_;
+      while (bytes_to_read > 0)
+       {
+         ssize_t len = ::read(o, p, bytes_to_read);
+         if (len < 0)
+           {
+             gold_info(_("%s: read failed: %s"), base_name, strerror(errno));
+             return false;
+           }
+         if (len == 0)
+           {
+             gold_info(_("%s: file too short: read only %lld of %lld bytes"),
+                       base_name,
+                       static_cast<long long>(s.st_size - bytes_to_read),
+                       static_cast<long long>(s.st_size));
+             return false;
+           }
+         p += len;
+         bytes_to_read -= len;
+       }
+      ::close(o);
+      return true;
+    }
+
   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())
+  if (!this->map_no_anonymous(writable))
     {
       release_descriptor(o, true);
       this->o_ = -1;
@@ -4042,10 +4943,23 @@ Output_file::resize(off_t file_size)
   // to unmap to flush to the file, then remap after growing the file.
   if (this->map_is_anonymous_)
     {
-      void* base = ::mremap(this->base_, this->file_size_, file_size,
-                            MREMAP_MAYMOVE);
-      if (base == MAP_FAILED)
-        gold_fatal(_("%s: mremap: %s"), this->name_, strerror(errno));
+      void* base;
+      if (!this->map_is_allocated_)
+       {
+         base = ::mremap(this->base_, this->file_size_, file_size,
+                         MREMAP_MAYMOVE);
+         if (base == MAP_FAILED)
+           gold_fatal(_("%s: mremap: %s"), this->name_, strerror(errno));
+       }
+      else
+       {
+         base = realloc(this->base_, file_size);
+         if (base == NULL)
+           gold_nomem();
+         if (file_size > this->file_size_)
+           memset(static_cast<char*>(base) + this->file_size_, 0,
+                  file_size - this->file_size_);
+       }
       this->base_ = static_cast<unsigned char*>(base);
       this->file_size_ = file_size;
     }
@@ -4053,7 +4967,7 @@ Output_file::resize(off_t file_size)
     {
       this->unmap();
       this->file_size_ = file_size;
-      if (!this->map_no_anonymous())
+      if (!this->map_no_anonymous(true))
        gold_fatal(_("%s: mmap: %s"), this->name_, strerror(errno));
     }
 }
@@ -4066,19 +4980,24 @@ 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)
+  if (base == MAP_FAILED)
     {
-      this->map_is_anonymous_ = true;
-      this->base_ = static_cast<unsigned char*>(base);
-      return true;
+      base = malloc(this->file_size_);
+      if (base == NULL)
+       return false;
+      memset(base, 0, this->file_size_);
+      this->map_is_allocated_ = true;
     }
-  return false;
+  this->base_ = static_cast<unsigned char*>(base);
+  this->map_is_anonymous_ = true;
+  return true;
 }
 
 // Map the file into memory.  Return whether the mapping succeeded.
+// If WRITABLE is true, map with write access.
 
 bool
-Output_file::map_no_anonymous()
+Output_file::map_no_anonymous(bool writable)
 {
   const int o = this->o_;
 
@@ -4100,12 +5019,18 @@ Output_file::map_no_anonymous()
   // 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));
+  if (writable)
+    {
+      int err = gold_fallocate(o, 0, this->file_size_);
+      if (err != 0)
+       gold_fatal(_("%s: %s"), this->name_, strerror(err));
+    }
 
   // Map the file into memory.
-  base = ::mmap(NULL, this->file_size_, PROT_READ | PROT_WRITE,
-               MAP_SHARED, o, 0);
+  int prot = PROT_READ;
+  if (writable)
+    prot |= PROT_WRITE;
+  base = ::mmap(NULL, this->file_size_, prot, 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
@@ -4123,7 +5048,8 @@ Output_file::map_no_anonymous()
 void
 Output_file::map()
 {
-  if (this->map_no_anonymous())
+  if (parameters->options().mmap_output_file()
+      && this->map_no_anonymous(true))
     return;
 
   // The mmap call might fail because of file system issues: the file
@@ -4144,8 +5070,16 @@ Output_file::map()
 void
 Output_file::unmap()
 {
-  if (::munmap(this->base_, this->file_size_) < 0)
-    gold_error(_("%s: munmap: %s"), this->name_, strerror(errno));
+  if (this->map_is_anonymous_)
+    {
+      // We've already written out the data, so there is no reason to
+      // waste time unmapping or freeing the memory.
+    }
+  else
+    {
+      if (::munmap(this->base_, this->file_size_) < 0)
+       gold_error(_("%s: munmap: %s"), this->name_, strerror(errno));
+    }
   this->base_ = NULL;
 }
 
@@ -4192,7 +5126,8 @@ Output_file::close()
 template
 off_t
 Output_section::add_input_section<32, false>(
-    Sized_relobj<32, false>* object,
+    Layout* layout,
+    Sized_relobj_file<32, false>* object,
     unsigned int shndx,
     const char* secname,
     const elfcpp::Shdr<32, false>& shdr,
@@ -4204,7 +5139,8 @@ Output_section::add_input_section<32, false>(
 template
 off_t
 Output_section::add_input_section<32, true>(
-    Sized_relobj<32, true>* object,
+    Layout* layout,
+    Sized_relobj_file<32, true>* object,
     unsigned int shndx,
     const char* secname,
     const elfcpp::Shdr<32, true>& shdr,
@@ -4216,7 +5152,8 @@ Output_section::add_input_section<32, true>(
 template
 off_t
 Output_section::add_input_section<64, false>(
-    Sized_relobj<64, false>* object,
+    Layout* layout,
+    Sized_relobj_file<64, false>* object,
     unsigned int shndx,
     const char* secname,
     const elfcpp::Shdr<64, false>& shdr,
@@ -4228,7 +5165,8 @@ Output_section::add_input_section<64, false>(
 template
 off_t
 Output_section::add_input_section<64, true>(
-    Sized_relobj<64, true>* object,
+    Layout* layout,
+    Sized_relobj_file<64, true>* object,
     unsigned int shndx,
     const char* secname,
     const elfcpp::Shdr<64, true>& shdr,