Add plugin functionality for link-time optimization (LTO).

include/:
	* plugin-api.h: New file.

gold/:
	* configure.ac (plugins): Add --enable-plugins option.
	* configure: Regenerate.
	* config.in: Regenerate.
	* Makefile.am (LIBDL): New variable.
	(CCFILES): Add plugin.cc.
	(HFILES): Add plugin.h.
	(ldadd_var): Add LIBDL.
	* Makefile.in: Regenerate.

	* archive.cc: Include "plugin.h".
	(Archive::setup): Don't preread archive symbols when using a plugin.
	(Archive::get_file_and_offset): Add memsize parameter.  Change callers.
	(Archive::get_elf_object_for_member): Call plugin hooks for claiming
	files.
	(Archive::include_member): Add symbols from plugin objects.
	* archive.h (Archive::get_file_and_offset): Add memsize parameter.
	* descriptors.cc (Descriptors::open): Check for file descriptors
	abandoned by plugins.
	(Descriptors::claim_for_plugin): New function.
	* descriptors.h (Descriptors::claim_for_plugin): New function.
	(Open_descriptor::is_claimed): New field.
	(claim_descriptor_for_plugin): New function.
	* fileread.cc (File_read::claim_for_plugin): New function.
	* fileread.h (File_read::claim_for_plugin): New function.
	(File_read::descriptor): New function.
	* gold.cc: Include "plugin.h".
	(queue_initial_tasks): Add task to call plugin hooks for generating
	new object files.
	* main.cc: Include "plugin.h".
	(main): Load plugin libraries.
	* object.h (Pluginobj): Declare.
	(Object::pluginobj): New function.
	(Object::do_pluginobj): New function.
	(Object::set_target): New function.
	* options.cc: Include "plugin.h".
	(General_options::parse_plugin): New function.
	(General_options::General_options): Initialize plugins_ field.
	(General_options::add_plugin): New function.
	* options.h (Plugin_manager): Declare.
	(General_options): Add --plugin option.
	(General_options::has_plugins): New function.
	(General_options::plugins): New function.
	(General_options::add_plugin): New function.
	(General_options::plugins_): New field.
	* plugin.cc: New file.
	* plugin.h: New file.
	* readsyms.cc: Include "plugin.h".
	(Read_symbols::do_read_symbols): Check for archive before checking
	for ELF file.  Call plugin hooks to claim files.
	* resolve.cc (Symbol_table::resolve): Record when symbol is referenced
	from a real object file; force override when processing replacement
	files.
	* symtab.cc (Symbol::init_fields): Initialize in_real_elf_ field.
	(Symbol::init_base_object): Likewise.
	(Symbol::init_base_output_data): Likewise.
	(Symbol::init_base_output_segment): Likewise.
	(Symbol::init_base_constant): Likewise.
	(Symbol::init_base_undefined): Likewise.
	(Symbol::output_section): Assert that object is not a plugin.
	(Symbol_table::add_from_pluginobj): New function.
	(Symbol_table::sized_finalize_symbol): Treat symbols from plugins as
	undefined.
	(Symbol_table::sized_write_globals): Likewise.
	(Symbol_table::add_from_pluginobj): Instantiate template.
	* symtab.h (Sized_pluginobj): Declare.
	(Symbol::in_real_elf): New function.
	(Symbol::set_in_real_elf): New function.
	(Symbol::in_real_elf_): New field.
	(Symbol_table::add_from_pluginobj): New function.

	* testsuite/Makefile.am (AM_CFLAGS): New variable.
	(LIBDL): New variable.
	(LDADD): Add LIBDL.
	(check_PROGRAMS): Add plugin_test_1 and plugin_test_2.
	(check_SCRIPTS): Add plugin_test_1.sh and plugin_test_2.sh.
	(check_DATA): Add plugin_test_1.err and plugin_test_2.err.
	(MOSTLYCLEANFILES): Likewise.
	* testsuite/Makefile.in: Regenerate.
	* testsuite/plugin_test.c: New file.
	* testsuite/plugin_test_1.sh: New file.
	* testsuite/plugin_test_2.sh: New file.

1 files changed, 23 insertions, 0 deletions

diff --git a/gold/options.h b/gold/options.h
index 2926730..167e58a 100644
--- a/gold/options.h
+++ b/gold/options.h
@@ -54,6 +54,7 @@ class Search_directory;
 class Input_file_group;
 class Position_dependent_options;
 class Target;
+class Plugin_manager;
 
 // The nested namespace is to contain all the global variables and
 // structs that need to be defined in the .h file, but do not need to
@@ -689,8 +690,14 @@ class General_options
   DEFINE_string(oformat, options::EXACTLY_TWO_DASHES, '\0', "elf",
 		N_("Set output format"), N_("[binary]"));
 
+#ifdef ENABLE_PLUGINS
+  DEFINE_special(plugin, options::TWO_DASHES, '\0',
+                 N_("Load a plugin library"), N_("PLUGIN[,ARG,...]"));
+#endif
+
   DEFINE_bool(preread_archive_symbols, options::TWO_DASHES, '\0', false,
               N_("Preread archive symbols when multi-threaded"), NULL);
+
   DEFINE_string(print_symbol_counts, options::TWO_DASHES, '\0', NULL,
 		N_("Print symbols defined and used for each input"),
 		N_("FILENAME"));
@@ -916,6 +923,16 @@ class General_options
   do_demangle() const
   { return this->do_demangle_; }
 
+  // Returns TRUE if any plugin libraries have been loaded.
+  bool
+  has_plugins() const
+  { return this->plugins_ != NULL; }
+
+  // Return a pointer to the plugin manager.
+  Plugin_manager*
+  plugins() const
+  { return this->plugins_; }
+
  private:
   // Don't copy this structure.
   General_options(const General_options&);
@@ -953,12 +970,18 @@ class General_options
   void
   add_sysroot();
 
+  // Add a plugin and its arguments to the list of plugins.
+  void
+  add_plugin(const char* arg);
+
   // Whether to mark the stack as executable.
   Execstack execstack_status_;
   // Whether to do a static link.
   bool static_;
   // Whether to do demangling.
   bool do_demangle_;
+  // List of plugin libraries.
+  Plugin_manager* plugins_;
 };
 
 // The position-dependent options.  We use this to store the state of