* gold.cc (queue_middle_tasks): Process existing GOT/PLT entries.

* incremental-dump.cc (dump_incremental_inputs): Mask high-order
	bit when checking got_type.
	* incremental.cc (Sized_incremental_binary::setup_readers):
	Store symbol table and string table locations; initialize bit vector
	of file status flags.
	(Sized_incremental_binary::do_reserve_layout): Set bit flag for
	unchanged files.
	(Sized_incremental_binary::do_process_got_plt): New function.
	(Sized_incremental_binary::get_symtab_view): Use stored locations.
	(Output_section_incremental_inputs::set_final_data_size): Record
	file index for each input file.
	(Output_section_incremental_inputs::write_got_plt): Store file index
	instead of input entry offset for each GOT entry.
	* incremental.h
	(Incremental_input_entry::Incremental_input_entry): Initialize new
	data member.
	(Incremental_input_entry::set_offset): Store file index.
	(Incremental_input_entry::get_file_index): New function.
	(Incremental_input_entry::file_index_): New data member.
	(Incremental_binary::process_got_plt): New function.
	(Incremental_binary::do_process_got_plt): New function.
	(Sized_incremental_binary::Sized_incremental_binary): Initialize new
	data members.
	(Sized_incremental_binary::~Sized_incremental_binary): New destructor.
	(Sized_incremental_binary::set_file_is_unchanged): New function.
	(Sized_incremental_binary::file_is_unchanged): New function.
	(Sized_incremental_binary::do_process_got_plt): New function.
	(Sized_incremental_binary::file_status_): New data member.
	(Sized_incremental_binary::main_symtab_loc_): New data member.
	(Sized_incremental_binary::main_strtab_loc_): New data member.
	* output.cc (Output_data_got::Got_entry::write): Add case
	RESERVED_CODE.
	(Output_data_got::add_global): Call add_got_entry.
	(Output_data_got::add_global_plt): Likewise.
	(Output_data_got::add_global_with_rel): Likewise.
	(Output_data_got::add_global_with_rela): Likewise.
	(Output_data_got::add_global_pair_with_rel): Call add_got_entry_pair.
	(Output_data_got::add_global_pair_with_rela): Likewise.
	(Output_data_got::add_local): Call add_got_entry.
	(Output_data_got::add_local_plt): Likewise.
	(Output_data_got::add_local_with_rel): Likewise.
	(Output_data_got::add_local_with_rela): Likewise.
	(Output_data_got::add_local_pair_with_rel): Call add_got_entry_pair.
	(Output_data_got::add_local_pair_with_rela): Likewise.
	(Output_data_got::reserve_slot): New function.
	(Output_data_got::reserve_slot_for_global): New function.
	(Output_data_got::add_got_entry): New function.
	(Output_data_got::add_got_entry_pair): New function.
	(Output_section::add_output_section_data): Edit FIXME.
	* output.h
	(Output_section_data_build::Output_section_data_build): New
	constructor with size parameter.
	(Output_data_space::Output_data_space): Likewise.
	(Output_data_got::Output_data_got): Initialize new data member; new
	constructor with size parameter.
	(Output_data_got::add_constant): Call add_got_entry.
	(Output_data_got::reserve_slot): New function.
	(Output_data_got::reserve_slot_for_global): New function.
	(class Output_data_got::Got_entry): Add RESERVED_CODE.
	(Output_data_got::add_got_entry): New function.
	(Output_data_got::add_got_entry_pair): New function.
	(Output_data_got::free_list_): New data member.
	* target.h (Sized_target::init_got_plt_for_update): New function.
	(Sized_target::register_global_plt_entry): New function.
	* x86_64.cc (Output_data_plt_x86_64::Output_data_plt_x86_64):
	Initialize new data member; call init; add constructor with PLT count.
	(Output_data_plt_x86_64::init): New function.
	(Output_data_plt_x86_64::add_relocation): New function.
	(Output_data_plt_x86_64::reserve_slot): New function.
	(Output_data_plt_x86_64::free_list_): New data member.
	(Target_x86_64::init_got_plt_for_update): New function.
	(Target_x86_64::register_global_plt_entry): New function.
	(Output_data_plt_x86_64::add_entry): Allocate from free list for
	incremental updates.
	(Output_data_plt_x86_64::add_relocation): New function.
	* testsuite/object_unittest.cc (Object_test): Set default options.

gold/output.cc

@@ -1358,6 +1358,13 @@ 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 Sized_relobj<size, big_endian>* object = this->u_.object;
@@ -1393,9 +1400,8 @@ Output_data_got<size, big_endian>::add_global(
   if (gsym->has_got_offset(got_type))
     return false;
 
-  this->entries_.push_back(Got_entry(gsym, false));
-  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;
 }
 
@@ -1409,9 +1415,8 @@ Output_data_got<size, big_endian>::add_global_plt(Symbol* gsym,
   if (gsym->has_got_offset(got_type))
     return false;
 
-  this->entries_.push_back(Got_entry(gsym, true));
-  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, true));
+  gsym->set_got_offset(got_type, got_offset);
   return true;
 }
 
@@ -1429,9 +1434,7 @@ Output_data_got<size, big_endian>::add_global_with_rel(
   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);
   rel_dyn->add_global(gsym, r_type, this, got_offset);
 }
@@ -1447,9 +1450,7 @@ Output_data_got<size, big_endian>::add_global_with_rela(
   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);
 }
@@ -1469,19 +1470,12 @@ Output_data_got<size, big_endian>::add_global_pair_with_rel(
   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);
 
-  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();
+    rel_dyn->add_global(gsym, r_type_2, this, got_offset + size / 8);
 }
 
 template<int size, bool big_endian>
@@ -1496,19 +1490,12 @@ Output_data_got<size, big_endian>::add_global_pair_with_rela(
   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);
   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();
+    rela_dyn->add_global(gsym, r_type_2, this, got_offset + size / 8, 0);
 }
 
 // Add an entry for a local symbol to the GOT.  This returns true if
@@ -1525,9 +1512,9 @@ Output_data_got<size, big_endian>::add_local(
   if (object->local_has_got_offset(symndx, got_type))
     return false;
 
-  this->entries_.push_back(Got_entry(object, symndx, false));
-  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;
 }
 
@@ -1543,9 +1530,9 @@ Output_data_got<size, big_endian>::add_local_plt(
   if (object->local_has_got_offset(symndx, got_type))
     return false;
 
-  this->entries_.push_back(Got_entry(object, symndx, true));
-  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,
+							  true));
+  object->set_local_got_offset(symndx, got_type, got_offset);
   return true;
 }
 
@@ -1564,9 +1551,7 @@ Output_data_got<size, big_endian>::add_local_with_rel(
   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);
   rel_dyn->add_local(object, symndx, r_type, this, got_offset);
 }
@@ -1583,9 +1568,7 @@ Output_data_got<size, big_endian>::add_local_with_rela(
   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);
 }
@@ -1607,20 +1590,15 @@ Output_data_got<size, big_endian>::add_local_pair_with_rel(
   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);
 
-  this->entries_.push_back(Got_entry(object, symndx, false));
   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(os, r_type_2, this, got_offset + size / 8);
 }
 
 template<int size, bool big_endian>
@@ -1637,20 +1615,37 @@ Output_data_got<size, big_endian>::add_local_pair_with_rela(
   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);
   rela_dyn->add_output_section(os, r_type_1, this, got_offset, 0);
 
-  this->entries_.push_back(Got_entry(object, symndx, false));
   if (r_type_2 != 0)
-    {
-      got_offset = this->last_got_offset();
-      rela_dyn->add_output_section(os, r_type_2, this, got_offset, 0);
-    }
+    rela_dyn->add_output_section(os, r_type_2, this, got_offset + size / 8, 0);
+}
 
-  this->set_got_size();
+// 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>::reserve_slot(unsigned int i)
+{
+  this->free_list_.remove(i * size / 8, (i + 1) * size / 8);
+}
+
+// Reserve a slot in the GOT for a global symbol.
+
+template<int size, bool big_endian>
+void
+Output_data_got<size, big_endian>::reserve_slot_for_global(
+    unsigned int i,
+    Symbol* gsym,
+    unsigned int got_type)
+{
+  this->free_list_.remove(i * size / 8, (i + 1) * size / 8);
+  gsym->set_got_offset(got_type, this->got_offset(i));
 }
 
 // Write out the GOT.
@@ -1682,6 +1677,63 @@ 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_fatal(_("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_fatal(_("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.
@@ -2335,7 +2387,8 @@ Output_section::add_output_section_data(Output_section_data* posd)
       uint64_t addr = this->address();
       posd->set_address(addr);
       posd->set_file_offset(0);
-      // FIXME: Mark *POSD as part of a fixed-layout section.
+      // FIXME: This should eventually be unreachable.
+      // gold_unreachable();
     }
 }