2009-09-17 Doug Kwan <dougkwan@google.com>

	* debug.h (DEBUG_RELAXATION): New constant.
	(DEBUG_ALL): Add DEBUG_RELAXATION.
	(debug_string_to_enum): Add relaxation debug option.
	* layout.cc
	(Layout::Relaxation_debug_check::check_output_data_for_reset_values,
	Layout::Relaxation_debug_check::read_sections,
	Layout::Relaxation_debug_check::read_sections): New method definitions.
	(Layout::Layout): Initialize data members
	record_output_section_data_from_scrips_,
	script_output_section_data_list_ and relaxation_debug_check_.
	(Layout::save_segments, Layout::restore_segments,
	Layout::clean_up_after_relaxation, Layout::prepare_for_relaxation,
	Layout::relaxation_loop_body): New method definitions.
	(Layout::finalize): Support relaxation.  Move section layout code to
	Layout::relaxation_loop_body.
	(Layout::set_asection_address_from_script): Move code for orphan
	section placement out.
	(Layout::place_orphan_sections_in_script): New method definition.
	* layout.h (Output_segment_headers, Output_file_header):
	New forward class declarations.
	(Layout::~Layout): Define.
	(Layout::new_output_section_data_from_script): New method definition.
	(Layout::place_orphan_sections_in_script): New method declaration.
	(Layout::Segment_states): New type declaration.
	(Layout::save_segments, Layout::restore_segments,
	Layout::clean_up_after_relaxation, Layout::prepare_for_relaxation,
	Layout::relaxation_loop_body): New method declarations.
	(Layout::Output_section_data_list): New type declaration.
	(Layout::Relaxation_debug_check): New class definition.
	(Layout::record_output_section_data_from_script_,
	Layout::script_output_section_data_list_, Layout::segment_states_,
	Layout::relaxation_debug_check_): New data members.
	* output.cc: (Output_section_headers::do_size): New method definition.
	(Output_section_headers::Output_section_headers): Move size
	computation to Output_section_headers::do_size.
	(Output_segment_headers::do_size): New method definition.
	(Output_file_header::Output_file_header): Move size computation to
	Output_file_header::do_size and call it.
	(Output_file_header::do_size): New method definition.
	(Output_data_group::Output_data_group): Adjust call to
	Output_section_data.
	(Output_data_dynamic::set_final_data_size): Add DT_NULL tag only once.
	(Output_symtab_xindex::do_write): Add array bound check.
 	(Output_section::Input_section::print_to_mapfile): Handle
	RELAXED_INPUT_SECTION_CODE.
	(Output_section::Output_section): Initialize data member checkpoint_.
	(Output_section::~Output_section): Delete checkpoint object pointed
	by checkpoint_.
	(Output_section::add_input_section): Always add an Input_section if
	relaxing.
	(Output_section::add_merge_input_section): Add assert.
	(Output_section::relax_input_section): New method definition.
	(Output_section::set_final_data_size): Set load address to zero for
	an unallocated section.
	(Output_section::do_address_and_file_offset_have_reset_values):
	New method definition.
	(Output_section::Input_section_sort_enty::Input_section_sort_enty):
	Handle relaxed input section.
	(Output_section::sort_attached_input_sections): Checkpoint input
	section list lazily.
	(Output_section::get_input_sections): Change type of input_sections to
	list of Simple_input_section pointers.  Checkpoint input section list
	lazily.  Also handle relaxed input sections.
	(Output_section::add_input_section_for_script): Take a reference to
	a Simple_input_section object instead of Relobj pointer and section
	index as parameter.  Handle relaxed input sections.
	(Output_section::save_states, Output_section::restore_states): New
	method definitions.
	* output.h (Output_data::Output_data): Initialize is_data_size_fixed_.
	(Output_data::is_data_size_fixed): New method definition.
	(Output_data::reset_addresss_and_file_offset): Do not reset data size
	if it is fixed.
	(Output_data::address_and_file_offset_have_reset_values): New method
	definition.
	(Output_data::do_address_and_file_offset_have_reset_values): New method
	definition.
	(Output_data::set_data_size): Check that data size is not fixed.
	(Output_data::fix_data_size): New method definition.
	(Output_data::is_data_size_fixed_): New data member.
	(Output_section_headers::set_final_data_size): New method definition.
	(Output_section_headers::do_size): New method declaration.
	(Output_segment_headers::set_final_data_size): New method definition.
	(Output_segment_headers::do_size): New method declaration.
	(Output_file_header::set_final_data_size)::New method definition.
	(Output_file_header::do_size)::New method declaration.
	(Output_section_data::Output_section_data): Add new parameter
	is_data_size_fixed and use it to fix data size.
	(Output_data_const::Output_data_const): Adjust call to base class
	constructor and fix data size.
	(Output_data_const_buffer::Output_data_const_buffer): Adjust call to
	base class constructor and fix data size.
	(Output_data_fixed_space::Output_data_fixed_space): Adjust call to
	base class constructor and fix data size.
	(Output_data_zero_fill::Output_data_zero_fill): Adjust call to base
	class constructor and fix data size.
	(Output_data_group::set_final_data_size): New method definition.
	(Output_data_dynamic::Dynamic_entry::tag): New method definition.
	(Output_symtab_xindex::Output_symtab_xindex): Adjust call to base
	class constructor and fix data size.
	(Output_relaxed_input_section): New class definition.
	(Output_section::Simple_input_section): New class definition.
	(Output_section::get_input_sections): Adjust parameter list.
	(Output_section::add_input_section_for_script): Same.
	(Output_section::save_states, Output_section::restore_states,
	Output_section::do_address_and_file_offset_have_reset_values,
	(Output_section::Input_section::Input_section): Handle
	RELAXED_INPUT_SECTION_CODE.  Add new overload for
	Output_relaxed_input_section.
	(Output_section::Input_section::is_input_section,
	Output_section::Input_section::set_output_section): Handle relaxed
	input section.
	(Output_section::Input_section::is_relaxed_input_section,
	Output_section::Input_section::output_section_data,
	Output_section::Input_section::relaxed_input_section): New method
	definitions.
	(Output_section::Input_section::RELAXED_INPUT_SECTION_CODE): New enum
	value.
	(Output_section::Input_section::u1_): Update comments.
	(Output_section::Input_section::u2_): Add new union member poris.
	(Output_section::Checkpoint_output_section): New classs definition.
	(Output_section::relax_input_section): New method declaration.
	(Output_section::checkpoint_): New data member.
	(Output_segment): Update comments.
	(Output_segment::Output_segment): Un-privatize copy constructor.
	(Output_segment::operator=): Un-privatize.
	* script-sections.cc (Output_section_element::Input_section_list):
	Change element type to Output_section::Simple_input_section.
	(Output_section_element_dot_assignment::set_section_addresses):
	Register output section data for relaxation clean up.
	(Output_data_exression::Output_data_expression): Adjust call to base
	constructor to fix data size.
	(Output_section_element_data::set_section_addresses): Register
	Output_data_expression object for relaxation clean up.
	(struct Input_section_info): Replace Relobj pointer and section index
	pair with Output_section::Simple_input_section and Convert struct to a
	class.
	(Input_section_sorter::operator()): Adjust access to
	Input_section_info data member to use accessors.
	(Output_section_element_input::set_section_addresses): Use layout
	parameter.  Adjust code to use Output_section::Simple_input_section
	and Input_secction_info classes.  Register filler for relaxation
	clean up.
	(Orphan_output_section::set_section_addresses): Replace Relobj pointer
	and section index pair with Output_section::Simple_input_section
	class.  Adjust code accordingly.
	(Phdrs_element::release_segment): New method definition.
	(Script_sections::attach_sections_using_phdrs_clause): Do not modify
	segment list.
	(Script_sections::release_segments): New method definition.
	* gold/script-sections.h (Script_sections::release_segments): New
	method declaration.
	* gold/target.h (Target::may_relax, Target::relax,
	Target::do_may_relax, Target::do_relax): New method definitions.

1 files changed, 98 insertions, 0 deletions

diff --git a/gold/layout.h b/gold/layout.h
index 0affa81..8856125 100644
--- a/gold/layout.h
+++ b/gold/layout.h
@@ -47,6 +47,8 @@ class Symbol_table;
 class Output_section_data;
 class Output_section;
 class Output_section_headers;
+class Output_segment_headers;
+class Output_file_header;
 class Output_segment;
 class Output_data;
 class Output_data_dynamic;
@@ -286,6 +288,12 @@ class Layout
  public:
   Layout(int number_of_input_files, Script_options*);
 
+  ~Layout()
+  {
+    delete this->relaxation_debug_check_;
+    delete this->segment_states_;
+  }
+
   // Given an input section SHNDX, named NAME, with data in SHDR, from
   // the object file OBJECT, return the output section where this
   // input section should go.  RELOC_SHNDX is the index of a
@@ -585,6 +593,15 @@ class Layout
   void
   attach_sections_to_segments();
 
+  // For relaxation clean up, we need to know output section data created
+  // from a linker script.
+  void
+  new_output_section_data_from_script(Output_section_data* posd)
+  {
+    if (this->record_output_section_data_from_script_)
+      this->script_output_section_data_list_.push_back(posd);
+  }
+
  private:
   Layout(const Layout&);
   Layout& operator=(const Layout&);
@@ -777,10 +794,42 @@ class Layout
   Output_segment*
   set_section_addresses_from_script(Symbol_table*);
 
+  // Find appropriate places or orphan sections in a script.
+  void
+  place_orphan_sections_in_script();
+
   // Return whether SEG1 comes before SEG2 in the output file.
   static bool
   segment_precedes(const Output_segment* seg1, const Output_segment* seg2);
 
+  // Use to save and restore segments during relaxation. 
+  typedef Unordered_map<const Output_segment*, const Output_segment*>
+    Segment_states;
+
+  // Save states of current output segments.
+  void
+  save_segments(Segment_states*);
+
+  // Restore output segment states.
+  void
+  restore_segments(const Segment_states*);
+
+  // Clean up after relaxation so that it is possible to lay out the
+  // sections and segments again.
+  void
+  clean_up_after_relaxation();
+
+  // Doing preparation work for relaxation.  This is factored out to make
+  // Layout::finalized a bit smaller and easier to read.
+  void
+  prepare_for_relaxation();
+
+  // Main body of the relaxation loop, which lays out the section.
+  off_t
+  relaxation_loop_body(int, Target*, Symbol_table*, Output_segment**,
+		       Output_segment*, Output_segment_headers*,
+		       Output_file_header*, unsigned int*);
+
   // A mapping used for kept comdats/.gnu.linkonce group signatures.
   typedef Unordered_map<std::string, Kept_section> Signatures;
 
@@ -807,6 +856,47 @@ class Layout
     { return Layout::segment_precedes(seg1, seg2); }
   };
 
+  typedef std::vector<Output_section_data*> Output_section_data_list;
+
+  // Debug checker class.
+  class Relaxation_debug_check
+  {
+   public:
+    Relaxation_debug_check()
+      : section_infos_()
+    { }
+ 
+    // Check that sections and special data are in reset states.
+    void
+    check_output_data_for_reset_values(const Layout::Section_list&,
+				       const Layout::Data_list&);
+  
+    // Record information of a section list.
+    void
+    read_sections(const Layout::Section_list&);
+
+    // Verify a section list with recorded information.
+    void
+    verify_sections(const Layout::Section_list&);
+ 
+   private:
+    // Information we care about a section.
+    struct Section_info
+    {
+      // Output section described by this.
+      Output_section* output_section;
+      // Load address.
+      uint64_t address;
+      // Data size.
+      off_t data_size;
+      // File offset.
+      off_t offset;
+    };
+
+    // Section information.
+    std::vector<Section_info> section_infos_;
+  };
+
   // The number of input files, for sizing tables.
   int number_of_input_files_;
   // Information set by scripts or by command line options.
@@ -889,6 +979,14 @@ class Layout
   // In incremental build, holds information check the inputs and build the
   // .gnu_incremental_inputs section.
   Incremental_inputs* incremental_inputs_;
+  // Whether we record output section data created in script
+  bool record_output_section_data_from_script_;
+  // List of output data that needs to be removed at relexation clean up.
+  Output_section_data_list script_output_section_data_list_;
+  // Structure to save segment states before entering the relaxation loop.
+  Segment_states* segment_states_;
+  // A relaxation debug checker.  We only create one when in debugging mode.
+  Relaxation_debug_check* relaxation_debug_check_;
 };
 
 // This task handles writing out data in output sections which is not