* layout.cc (Layout::include_section): Refactored check for debug

	info section.
	(Layout::add_comdat): Add new parameters.  Change type
	of signature parameter.  Add object and shndx to signatures table.
	(Layout::find_kept_object): New function.
	* layout.h: Include <cstring>.
	(Layout::is_debug_info_section): New function.
	(Layout::add_comdat): Add new parameters.
	(Layout::find_kept_object): New function.
	(Layout::Kept_section): New struct.
	(Layout::Signatures): Change type of map range.
	* object.cc (Relobj::output_section_address): New function.
	(Sized_relobj::include_section_group): Add new parameters.  Change
	calls to Layout::add_comdat.  Change to build table of kept comdat
	groups and table mapping discarded sections to kept sections.
	(Sized_relobj::include_linkonce_section): Likewise.  Add new parameter.
	(Sized_relobj::do_layout): Change calls to include_section_group and
	include_linkonce_section.
	(Sized_relobj::do_finalize_local_symbols): Do not set local symbol
	value to zero when section is discarded.
	(Sized_relobj::map_to_kept_section): New function.
	* object.h (Relobj::output_section_address): New function.
	(Relobj::Comdat_group): New type.
	(Relobj::find_comdat_group): New function.
	(Relobj::Comdat_group_table): New type.
	(Relobj::Kept_comdat_section): New type.
	(Relobj::Kept_comdat_section_table): New type.
	(Relobj::add_comdat_group): New function.
	(Relobj::set_kept_comdat_section): New function.
	(Relobj::get_kept_comdat_section): New function.
	(Relobj::comdat_groups_): New field.
	(Relobj::kept_comdat_sections_): New field.
	(Symbol_value::input_value): Update comment.
	(Sized_relobj::map_to_kept_section) New function.
	(Sized_relobj::include_linkonce_section): Add new parameter.
	* target-reloc.h (Comdat_behavior): New type.
	(get_comdat_behavior): New function.
	(relocate_section): Add code to map a discarded section to the
	corresponding kept section when applying a relocation.

1 files changed, 32 insertions, 2 deletions

diff --git a/gold/layout.h b/gold/layout.h
index efa8b61..8584a0c 100644
--- a/gold/layout.h
+++ b/gold/layout.h
@@ -23,6 +23,7 @@
 #ifndef GOLD_LAYOUT_H
 #define GOLD_LAYOUT_H
 
+#include <cstring>
 #include <list>
 #include <string>
 #include <utility>
@@ -212,12 +213,29 @@ class Layout
   is_linkonce(const char* name)
   { return strncmp(name, ".gnu.linkonce", sizeof(".gnu.linkonce") - 1) == 0; }
 
+  // Return true if a section is a debugging section.
+  static inline bool
+  is_debug_info_section(const char* name)
+  {
+    // Debugging sections can only be recognized by name.
+    return (strncmp(name, ".debug", sizeof(".debug") - 1) == 0
+            || strncmp(name, ".gnu.linkonce.wi.", 
+                       sizeof(".gnu.linkonce.wi.") - 1) == 0
+            || strncmp(name, ".line", sizeof(".line") - 1) == 0
+            || strncmp(name, ".stab", sizeof(".stab") - 1) == 0);
+  }
+
   // Record the signature of a comdat section, and return whether to
   // include it in the link.  The GROUP parameter is true for a
   // section group signature, false for a signature derived from a
   // .gnu.linkonce section.
   bool
-  add_comdat(const char*, bool group);
+  add_comdat(Relobj*, unsigned int, const std::string&, bool group);
+
+  // Find the given comdat signature, and return the object and section
+  // index of the kept group.
+  Relobj*
+  find_kept_object(const std::string&, unsigned int*) const;
 
   // Finalize the layout after all the input sections have been added.
   off_t
@@ -550,7 +568,19 @@ class Layout
   segment_precedes(const Output_segment* seg1, const Output_segment* seg2);
 
   // A mapping used for group signatures.
-  typedef Unordered_map<std::string, bool> Signatures;
+  struct Kept_section
+    {
+      Kept_section()
+        : object_(NULL), shndx_(0), group_(false)
+      { }
+      Kept_section(Relobj* object, unsigned int shndx, bool group)
+        : object_(object), shndx_(shndx), group_(group)
+      { }
+      Relobj* object_;
+      unsigned int shndx_;
+      bool group_;
+    };
+  typedef Unordered_map<std::string, Kept_section> Signatures;
 
   // Mapping from input section name/type/flags to output section.  We
   // use canonicalized strings here.