Convert observers to C++

This converts observers from using a special source-generating script
to be plain C++.  This version of the patch takes advantage of C++11
by using std::function and variadic templates; incorporates Pedro's
patches; and renames the header file to "observable.h" (this change
eliminates the need for a clean rebuild).

Note that Pedro's patches used a template lambda in tui-hooks.c, but
this failed to compile on some buildbot instances (presumably due to
differing C++ versions); I replaced this with an ordinary template
function.

Regression tested on the buildbot.

gdb/ChangeLog
2018-03-19  Pedro Alves  <palves@redhat.com>
	    Tom Tromey  <tom@tromey.com>

	* unittests/observable-selftests.c: New file.
	* common/observable.h: New file.
	* observable.h: New file.
	* ada-lang.c, ada-tasks.c, agent.c, aix-thread.c, annotate.c,
	arm-tdep.c, auto-load.c, auxv.c, break-catch-syscall.c,
	breakpoint.c, bsd-uthread.c, cli/cli-interp.c, cli/cli-setshow.c,
	corefile.c, dummy-frame.c, event-loop.c, event-top.c, exec.c,
	extension.c, frame.c, gdbarch.c, guile/scm-breakpoint.c,
	infcall.c, infcmd.c, inferior.c, inflow.c, infrun.c, jit.c,
	linux-tdep.c, linux-thread-db.c, m68klinux-tdep.c,
	mi/mi-cmd-break.c, mi/mi-interp.c, mi/mi-main.c, objfiles.c,
	ppc-linux-nat.c, ppc-linux-tdep.c, printcmd.c, procfs.c,
	python/py-breakpoint.c, python/py-finishbreakpoint.c,
	python/py-inferior.c, python/py-unwind.c, ravenscar-thread.c,
	record-btrace.c, record-full.c, record.c, regcache.c, remote.c,
	riscv-tdep.c, sol-thread.c, solib-aix.c, solib-spu.c, solib.c,
	spu-multiarch.c, spu-tdep.c, stack.c, symfile-mem.c, symfile.c,
	symtab.c, thread.c, top.c, tracepoint.c, tui/tui-hooks.c,
	tui/tui-interp.c, valops.c: Update all users.
	* tui/tui-hooks.c (tui_bp_created_observer)
	(tui_bp_deleted_observer, tui_bp_modified_observer)
	(tui_inferior_exit_observer, tui_before_prompt_observer)
	(tui_normal_stop_observer, tui_register_changed_observer):
	Remove.
	(tui_observers_token): New global.
	(attach_or_detach, tui_attach_detach_observers): New functions.
	(tui_install_hooks, tui_remove_hooks): Use
	tui_attach_detach_observers.
	* record-btrace.c (record_btrace_thread_observer): Remove.
	(record_btrace_thread_observer_token): New global.
	* observer.sh: Remove.
	* observer.c: Rename to observable.c.
	* observable.c (namespace gdb_observers): Define new objects.
	(observer_debug): Move into gdb_observers namespace.
	(struct observer, struct observer_list, xalloc_observer_list_node)
	(xfree_observer_list_node, generic_observer_attach)
	(generic_observer_detach, generic_observer_notify): Remove.
	(_initialize_observer): Update.
	Don't include observer.inc.
	* Makefile.in (generated_files): Remove observer.h, observer.inc.
	(clean mostlyclean): Likewise.
	(observer.h, observer.inc): Remove targets.
	(SUBDIR_UNITTESTS_SRCS): Add observable-selftests.c.
	(COMMON_SFILES): Use observable.c, not observer.c.
	* .gitignore: Remove observer.h.

gdb/doc/ChangeLog
2018-03-19  Tom Tromey  <tom@tromey.com>

	* observer.texi: Remove.

gdb/testsuite/ChangeLog
2018-03-19  Tom Tromey  <tom@tromey.com>

	* gdb.gdb/observer.exp: Remove.

1 files changed, 8 insertions, 8 deletions

diff --git a/gdb/symfile.c b/gdb/symfile.c
index e202ca2..9571664 100644
--- a/gdb/symfile.c
+++ b/gdb/symfile.c
@@ -46,7 +46,7 @@
 #include "hashtab.h"
 #include "readline/readline.h"
 #include "block.h"
-#include "observer.h"
+#include "observable.h"
 #include "exec.h"
 #include "parser-defs.h"
 #include "varobj.h"
@@ -1152,13 +1152,13 @@ symbol_file_add_with_addrs (bfd *abfd, const char *name,
 
   if (objfile->sf == NULL)
     {
-      observer_notify_new_objfile (objfile);
+      gdb::observers::new_objfile.notify (objfile);
       return objfile;	/* No symbols.  */
     }
 
   finish_new_objfile (objfile, add_flags);
 
-  observer_notify_new_objfile (objfile);
+  gdb::observers::new_objfile.notify (objfile);
 
   bfd_cache_close_all ();
   return (objfile);
@@ -2511,14 +2511,14 @@ reread_symbols (void)
       clear_symtab_users (0);
 
       /* clear_objfile_data for each objfile was called before freeing it and
-	 observer_notify_new_objfile (NULL) has been called by
+	 gdb::observers::new_objfile.notify (NULL) has been called by
 	 clear_symtab_users above.  Notify the new files now.  */
       for (auto iter : new_objfiles)
-	observer_notify_new_objfile (iter);
+	gdb::observers::new_objfile.notify (objfile);
 
       /* At least one objfile has changed, so we can consider that
          the executable we're debugging has changed too.  */
-      observer_notify_executable_changed ();
+      gdb::observers::executable_changed.notify ();
     }
 }
 
@@ -2755,7 +2755,7 @@ clear_symtab_users (symfile_add_flags add_flags)
   clear_displays ();
   clear_last_displayed_sal ();
   clear_pc_function_cache ();
-  observer_notify_new_objfile (NULL);
+  gdb::observers::new_objfile.notify (NULL);
 
   /* Clear globals which might have pointed into a removed objfile.
      FIXME: It's not clear which of these are supposed to persist
@@ -3761,7 +3761,7 @@ _initialize_symfile (void)
 {
   struct cmd_list_element *c;
 
-  observer_attach_free_objfile (symfile_free_objfile);
+  gdb::observers::free_objfile.attach (symfile_free_objfile);
 
 #define READNOW_READNEVER_HELP \
   "The '-readnow' option will cause GDB to read the entire symbol file\n\