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.

2 files changed, 51 insertions, 48 deletions

diff --git a/gdb/tui/tui-hooks.c b/gdb/tui/tui-hooks.c
index 84e416e..efa02e2 100644
--- a/gdb/tui/tui-hooks.c
+++ b/gdb/tui/tui-hooks.c
@@ -32,7 +32,7 @@
 #include "breakpoint.h"
 #include "ui-out.h"
 #include "top.h"
-#include "observer.h"
+#include "observable.h"
 #include <unistd.h>
 #include <fcntl.h>
 
@@ -203,14 +203,42 @@ tui_normal_stop (struct bpstats *bs, int print_frame)
   tui_refresh_frame_and_register_information (/*registers_too_p=*/1);
 }
 
-/* Observers created when installing TUI hooks.  */
-static struct observer *tui_bp_created_observer;
-static struct observer *tui_bp_deleted_observer;
-static struct observer *tui_bp_modified_observer;
-static struct observer *tui_inferior_exit_observer;
-static struct observer *tui_before_prompt_observer;
-static struct observer *tui_normal_stop_observer;
-static struct observer *tui_register_changed_observer;
+/* Token associated with observers registered while TUI hooks are
+   installed.  */
+static const gdb::observers::token tui_observers_token;
+
+/* Attach or detach a single observer, according to ATTACH.  */
+
+template<typename T>
+static void
+attach_or_detach (T &observable, typename T::func_type func, bool attach)
+{
+  if (attach)
+    observable.attach (func, tui_observers_token);
+  else
+    observable.detach (tui_observers_token);
+}
+
+/* Attach or detach TUI observers, according to ATTACH.  */
+
+static void
+tui_attach_detach_observers (bool attach)
+{
+  attach_or_detach (gdb::observers::breakpoint_created,
+		    tui_event_create_breakpoint, attach);
+  attach_or_detach (gdb::observers::breakpoint_deleted,
+		    tui_event_delete_breakpoint, attach);
+  attach_or_detach (gdb::observers::breakpoint_modified,
+		    tui_event_modify_breakpoint, attach);
+  attach_or_detach (gdb::observers::inferior_exit,
+		    tui_inferior_exit, attach);
+  attach_or_detach (gdb::observers::before_prompt,
+		    tui_before_prompt, attach);
+  attach_or_detach (gdb::observers::normal_stop,
+		    tui_normal_stop, attach);
+  attach_or_detach (gdb::observers::register_changed,
+		    tui_register_changed, attach);
+}
 
 /* Install the TUI specific hooks.  */
 void
@@ -224,20 +252,7 @@ tui_install_hooks (void)
     = tui_dummy_print_frame_info_listing_hook;
 
   /* Install the event hooks.  */
-  tui_bp_created_observer
-    = observer_attach_breakpoint_created (tui_event_create_breakpoint);
-  tui_bp_deleted_observer
-    = observer_attach_breakpoint_deleted (tui_event_delete_breakpoint);
-  tui_bp_modified_observer
-    = observer_attach_breakpoint_modified (tui_event_modify_breakpoint);
-  tui_inferior_exit_observer
-    = observer_attach_inferior_exit (tui_inferior_exit);
-  tui_before_prompt_observer
-    = observer_attach_before_prompt (tui_before_prompt);
-  tui_normal_stop_observer
-    = observer_attach_normal_stop (tui_normal_stop);
-  tui_register_changed_observer
-    = observer_attach_register_changed (tui_register_changed);
+  tui_attach_detach_observers (true);
 }
 
 /* Remove the TUI specific hooks.  */
@@ -246,26 +261,14 @@ tui_remove_hooks (void)
 {
   deprecated_print_frame_info_listing_hook = 0;
   deprecated_query_hook = 0;
+
   /* Remove our observers.  */
-  observer_detach_breakpoint_created (tui_bp_created_observer);
-  tui_bp_created_observer = NULL;
-  observer_detach_breakpoint_deleted (tui_bp_deleted_observer);
-  tui_bp_deleted_observer = NULL;
-  observer_detach_breakpoint_modified (tui_bp_modified_observer);
-  tui_bp_modified_observer = NULL;
-  observer_detach_inferior_exit (tui_inferior_exit_observer);
-  tui_inferior_exit_observer = NULL;
-  observer_detach_before_prompt (tui_before_prompt_observer);
-  tui_before_prompt_observer = NULL;
-  observer_detach_normal_stop (tui_normal_stop_observer);
-  tui_normal_stop_observer = NULL;
-  observer_detach_register_changed (tui_register_changed_observer);
-  tui_register_changed_observer = NULL;
+  tui_attach_detach_observers (false);
 }
 
 void
 _initialize_tui_hooks (void)
 {
   /* Install the permanent hooks.  */
-  observer_attach_new_objfile (tui_new_objfile_hook);
+  gdb::observers::new_objfile.attach (tui_new_objfile_hook);
 }
diff --git a/gdb/tui/tui-interp.c b/gdb/tui/tui-interp.c
index 3c87198..cf32c90 100644
--- a/gdb/tui/tui-interp.c
+++ b/gdb/tui/tui-interp.c
@@ -31,7 +31,7 @@
 #include "tui/tui.h"
 #include "tui/tui-io.h"
 #include "infrun.h"
-#include "observer.h"
+#include "observable.h"
 #include "gdbthread.h"
 
 /* Set to 1 when the TUI mode must be activated when we first start
@@ -326,14 +326,14 @@ _initialize_tui_interp (void)
     }
 
   /* If changing this, remember to update cli-interp.c as well.  */
-  observer_attach_normal_stop (tui_on_normal_stop);
-  observer_attach_signal_received (tui_on_signal_received);
-  observer_attach_end_stepping_range (tui_on_end_stepping_range);
-  observer_attach_signal_exited (tui_on_signal_exited);
-  observer_attach_exited (tui_on_exited);
-  observer_attach_no_history (tui_on_no_history);
-  observer_attach_sync_execution_done (tui_on_sync_execution_done);
-  observer_attach_command_error (tui_on_command_error);
-  observer_attach_user_selected_context_changed
+  gdb::observers::normal_stop.attach (tui_on_normal_stop);
+  gdb::observers::signal_received.attach (tui_on_signal_received);
+  gdb::observers::end_stepping_range.attach (tui_on_end_stepping_range);
+  gdb::observers::signal_exited.attach (tui_on_signal_exited);
+  gdb::observers::exited.attach (tui_on_exited);
+  gdb::observers::no_history.attach (tui_on_no_history);
+  gdb::observers::sync_execution_done.attach (tui_on_sync_execution_done);
+  gdb::observers::command_error.attach (tui_on_command_error);
+  gdb::observers::user_selected_context_changed.attach
     (tui_on_user_selected_context_changed);
 }