2009-01-20 Sriraman Tallam <tmsriram@google.com>

	* Makefile.am (CCFILES): Add gc.cc.
	(HFILES): Add gc.h.
	* Makefile.in: Regenerate.
	* gold.cc (Gc_runner): New class.
	(queue_initial_tasks): Call garbage collection related tasks
	when corresponding options are invoked.
	(queue_middle_gc_tasks): New function.
	(queue_middle_tasks): Reorder tasks to allow relocs to be read and
	processed early before laying out sections during garbage collection.
	* gold.h (queue_middle_gc_tasks): New function.
	(is_prefix_of): Move from "layout.cc".
	* i386.cc (Target_i386::gc_process_relocs): New function.
	* layout.cc (is_prefix_of): Remove. Move to "gold.h"
	* main.cc (main): Create object of class "Garbage_collection".
	* object.cc (Relobj::copy_symbols_data): New function.
	(Relobj::is_section_name_included): New function.
	(Sized_relobj::do_layout): Allow this function to be called twice
	during garbage collection and defer layout of section during the
	first call.
	* object.h (Relobj::get_symbols_data): New function.
	(Relobj::is_section_name_included): New function.
	(Relobj::copy_symbols_data): New function.
	(Relobj::set_symbols_data): New function.
	(Relobj::get_relocs_data): New function.
	(Relobj::set_relocs_data): New function.
	(Relobj::is_output_section_offset_invalid): New pure virtual function.
	(Relobj::gc_process_relocs): New function.
	(Relobj::do_gc_process_relocs): New pure virtual function.
	(Relobj::sd_): New data member.
	(Sized_relobj::is_output_section_offset_invalid): New function.
	(Sized_relobj::do_gc_process_relocs): New function.
	* options.h (General_options::gc_sections): Modify to not be a no-op.
	(General_options::print_gc_sections): New option.
	* plugin.cc (Plugin_finish::run): Remove function call to
	Plugin_manager::layout_deferred_objects.  Move it to "gold.cc".
	* powerpc.cc (Target_powerpc::gc_process_relocs): New function.
	* reloc.cc (Read_relocs::run): Add task to process relocs and
	determine unreferenced sections when doing garbage collection.
	(Gc_process_relocs): New class.
	(Sized_relobj::do_gc_process_relocs): New function.
	(Sized_relobj::do_scan_relocs): Don't try to scan the relocs for
	sections that are garbage collected.
	* reloc.h (Gc_process_relocs): New class.
	* sparc.cc (Target_sparc::gc_process_relocs): New function.
	* symtab.cc (Symbol::should_add_dynsym_entry): Do not add entries for
	symbols whose corresponding sections are garbage collected.
	(Symbol_table::Symbol_table): Add new parameter for the garbage
	collection object.
	(Symbol_table::gc_mark_undef_symbols): New function.
	(Symbol_table::gc_mark_symbol_for_shlib): New function.
	(Symbol_table::gc_mark_dyn_syms): New function.
	(Symbol_table::resolve): Do not treat symbols seen in dynamic objects
	as garbage.
	(Symbol_table::add_from_object): Likewise.
	(Symbol_table::add_from_relobj): When building shared objects, do not
	treat externally visible symbols as garbage.
	(Symbol_table::sized_finalize_symbol): Do not check dynamic symbol
	table information for static and relocatable links.
	* symtab.h (Symbol_table::set_gc): New function.
	(Symbol_table::gc): New function.
	(Symbol_table::gc_mark_undef_symbols): New function.
	(Symbol_table::gc_mark_symbol_for_shlib): New function.
	(Symbol_table::gc_mark_dyn_syms): New function.
	(Symbol_table::gc_): New data member.
	* target.h (Sized_target::gc_process_relocs): New pure virtual
	function.
	* x86_64.cc (Target_x86_64::gc_process_relocs): New function.
	* testsuite/testfile.cc (Target_test::gc_process_relocs): New function.

1 files changed, 49 insertions, 1 deletions

diff --git a/gold/i386.cc b/gold/i386.cc
index 8a5558e..3779d4e 100644
--- a/gold/i386.cc
+++ b/gold/i386.cc
@@ -1,6 +1,6 @@
 // i386.cc -- i386 target support for gold.
 
-// Copyright 2006, 2007, 2008 Free Software Foundation, Inc.
+// Copyright 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
 // Written by Ian Lance Taylor <iant@google.com>.
 
 // This file is part of gold.
@@ -62,6 +62,22 @@ class Target_i386 : public Sized_target<32, false>
       got_mod_index_offset_(-1U), tls_base_symbol_defined_(false)
   { }
 
+  // Process the relocations to determine unreferenced sections for 
+  // garbage collection.
+  void
+  gc_process_relocs(const General_options& options,
+                    Symbol_table* symtab,
+                    Layout* layout,
+                    Sized_relobj<32, false>* object,
+                    unsigned int data_shndx,
+                    unsigned int sh_type,
+                    const unsigned char* prelocs,
+                    size_t reloc_count,
+                    Output_section* output_section,
+                    bool needs_special_offset_handling,
+                    size_t local_symbol_count,
+                    const unsigned char* plocal_symbols);
+
   // Scan the relocations to look for symbol adjustments.
   void
   scan_relocs(const General_options& options,
@@ -1456,6 +1472,38 @@ Target_i386::Scan::global(const General_options&,
     }
 }
 
+// Process relocations for gc.
+
+void
+Target_i386::gc_process_relocs(const General_options& options,
+                               Symbol_table* symtab,
+                               Layout* layout,
+                               Sized_relobj<32, false>* object,
+                               unsigned int data_shndx,
+                               unsigned int,
+                               const unsigned char* prelocs,
+                               size_t reloc_count,
+                               Output_section* output_section,
+                               bool needs_special_offset_handling,
+                               size_t local_symbol_count,
+                               const unsigned char* plocal_symbols)
+{
+  gold::gc_process_relocs<32, false, Target_i386, elfcpp::SHT_REL,
+		          Target_i386::Scan>(
+    options,
+    symtab,
+    layout,
+    this,
+    object,
+    data_shndx,
+    prelocs,
+    reloc_count,
+    output_section,
+    needs_special_offset_handling,
+    local_symbol_count,
+    plocal_symbols);
+}
+
 // Scan relocations for a section.
 
 void