Patch adds support to allow plugins to map selected subset of sections to unique

segments.


2012-08-24  Sriraman Tallam  <tmsriram@google.com>

	* gold.cc (queue_middle_tasks): Call layout again when unique
	segments for sections is desired.
	* layout.cc (Layout::Layout): Initialize new members.
	(Layout::get_output_section_flags): New function.
	(Layout::choose_output_section): Call get_output_section_flags.
	(Layout::layout): Make output section for mapping to a unique segment.
	(Layout::insert_section_segment_map): New function.
	(Layout::attach_allocated_section_to_segment): Make unique segment for
	output sections marked so.
	(Layout::segment_precedes): Check for unique segments when sorting.
	* layout.h (Layout::Unique_segment_info): New struct.
	(Layout::Section_segment_map): New typedef.
	(Layout::insert_section_segment_map): New function.
	(Layout::get_output_section_flags): New function.
	(Layout::is_unique_segment_for_sections_specified): New function.
	(Layout::set_unique_segment_for_sections_specified): New function.
	(Layout::unique_segment_for_sections_specified_): New member.
	(Layout::section_segment_map_): New member.
	* object.cc (Sized_relobj_file<size, big_endian>::do_layout):
	Rename is_gc_pass_one to is_pass_one.
	Rename is_gc_pass_two to is_pass_two.
	Rename is_gc_or_icf to is_two_pass.
	Check for which pass based on whether symbols data is present.
	Make it two pass when unique segments for sections is desired.
	* output.cc (Output_section::Output_section): Initialize new
	members.
	* output.h (Output_section::is_unique_segment): New function.
	(Output_section::set_is_unique_segment): New function.
	(Output_section::is_unique_segment_): New member.
	(Output_section::extra_segment_flags): New function.
	(Output_section::set_extra_segment_flags): New function.
	(Output_section::extra_segment_flags_): New member.
	(Output_section::segment_alignment): New function.
	(Output_section::set_segment_alignment): New function.
	(Output_section::segment_alignment_): New member.
	(Output_segment::Output_segment): Initialize is_unique_segment_.
	(Output_segment::is_unique_segment): New function.
	(Output_segment::set_is_unique_segment): New function.
	(Output_segment::is_unique_segment_): New member.
	* plugin.cc (allow_unique_segment_for_sections): New function.
	(unique_segment_for_sections): New function.
	(Plugin::load): Add new functions to transfer vector.
	* Makefile.am (plugin_final_layout.readelf.stdout): Add readelf output.
	* Makefile.in: Regenerate.
	* testsuite/plugin_final_layout.sh: Check if unique segment
	functionality works.
	* testsuite/plugin_section_order.c (onload): Check if new interfaces
	are available.
	(allow_unique_segment_for_sections): New global.
	(unique_segment_for_sections): New global.
	(claim_file_hook): Call allow_unique_segment_for_sections.
	(all_symbols_read_hook): Call unique_segment_for_sections.


2012-08-24  Sriraman Tallam  <tmsriram@google.com>

	* plugin-api.h (ld_plugin_allow_unique_segment_for_sections):
	New interface.
	(ld_plugin_unique_segment_for_sections): New interface.
	(LDPT_ALLOW_UNIQUE_SEGMENT_FOR_SECTIONS): New enum val.
	(LDPT_UNIQUE_SEGMENT_FOR_SECTIONS): New enum val.
	(tv_allow_unique_segment_for_sections): New member.
	(tv_unique_segment_for_sections): New member.

1 files changed, 42 insertions, 0 deletions

diff --git a/gold/output.h b/gold/output.h
index 9b0f87f..25a6b89 100644
--- a/gold/output.h
+++ b/gold/output.h
@@ -3265,6 +3265,28 @@ class Output_section : public Output_data
   requires_postprocessing() const
   { return this->requires_postprocessing_; }
 
+  bool
+  is_unique_segment() const
+  { return this->is_unique_segment_; }
+
+  void
+  set_is_unique_segment()
+  { this->is_unique_segment_ = true; }
+
+  uint64_t extra_segment_flags() const
+  { return this->extra_segment_flags_; }
+
+  void
+  set_extra_segment_flags(uint64_t flags)
+  { this->extra_segment_flags_ = flags; }
+
+  uint64_t segment_alignment() const
+  { return this->segment_alignment_; }
+
+  void
+  set_segment_alignment(uint64_t align)
+  { this->segment_alignment_ = align; }
+  
   // If a section requires postprocessing, return the buffer to use.
   unsigned char*
   postprocessing_buffer() const
@@ -4216,9 +4238,17 @@ class Output_section : public Output_data
   bool has_fixed_layout_ : 1;
   // True if we can add patch space to this section.
   bool is_patch_space_allowed_ : 1;
+  // True if this output section goes into a unique segment.
+  bool is_unique_segment_ : 1;
   // For SHT_TLS sections, the offset of this section relative to the base
   // of the TLS segment.
   uint64_t tls_offset_;
+  // Additional segment flags, specified via linker plugin, when mapping some
+  // input sections to unique segments.
+  uint64_t extra_segment_flags_; 
+  // Segment alignment specified via linker plugin, when mapping some
+  // input sections to unique segments.
+  uint64_t segment_alignment_;
   // Saved checkpoint.
   Checkpoint_output_section* checkpoint_;
   // Fast lookup maps for merged and relaxed input sections.
@@ -4294,6 +4324,16 @@ class Output_segment
   set_is_large_data_segment()
   { this->is_large_data_segment_ = true; }
 
+  bool
+  is_unique_segment() const
+  { return this->is_unique_segment_; }
+
+  // Mark segment as unique, happens when linker plugins request that
+  // certain input sections be mapped to unique segments.
+  void
+  set_is_unique_segment()
+  { this->is_unique_segment_ = true; }
+
   // Return the maximum alignment of the Output_data.
   uint64_t
   maximum_alignment();
@@ -4504,6 +4544,8 @@ class Output_segment
   bool are_addresses_set_ : 1;
   // Whether this segment holds large data sections.
   bool is_large_data_segment_ : 1;
+  // Whether this was marked as a unique segment via a linker plugin.
+  bool is_unique_segment_ : 1;
 };
 
 // This class represents the output file.