Patchwork [RFA] Convert observers to C++

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Submitter Tom Tromey
Date Feb. 10, 2018, 3:38 a.m.
Message ID <87vaf5a4zq.fsf@tromey.com>
Download mbox | patch
Permalink /patch/25899/
State New
Headers show

Comments

Tom Tromey - Feb. 10, 2018, 3:38 a.m.
>>>>> "Tom" == Tom Tromey <tom@tromey.com> writes:

Tom> I'm running this through the buildbot again and when it is working I
Tom> will re-submit it.

Here it is.

Tom

commit 896e8cda2231609868e720beb8937b28261e92a0
Author: Tom Tromey <tom@tromey.com>
Date:   Sun Oct 2 10:50:20 2016 -0600

    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.
    
    This patch will require a clean build, because observer.h now appears
    in the source directory.  If this seems inconvenient, I could choose a
    different name for the new header, like "gdb_observers.h".
    
    Regression tested on the buildbot.
    
    gdb/ChangeLog
    2017-11-07  Tom Tromey  <tom@tromey.com>
    
            * common/observable.h: New file.
            * observer.h (gdb_observers) <test_notification>: Remove.
            * observer.c: Include selftest.h.
            (test_notification): Now static.
            (test_first_observer, test_second_observer, test_third_observer)
            (test_first_notification_function)
            (test_second_notification_function)
            (test_third_notification_function): Renamed.  Now static.
            (check_counters, observer_self_tests): New function.
            (_initialize_observer): Register observer_self_tests.
            * 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,
            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): Change
            type.
            * record-btrace.c (record_btrace_thread_observer): Change type.
            (_initialize_record_btrace): Initialize
            record_btrace_thread_observer.
            * observer.sh: Remove.
            * observer.h: New file.
            * observer.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.
            * .gitignore: Remove observer.h.
    
    gdb/doc/ChangeLog
    2017-11-04  Tom Tromey  <tom@tromey.com>
    
            * observer.texi: Remove.
    
    gdb/testsuite/ChangeLog
    2017-11-04  Tom Tromey  <tom@tromey.com>
    
            * gdb.gdb/observer.exp: Remove.

Patch

diff --git a/gdb/.gitignore b/gdb/.gitignore
index e7e108768e..b9b2c6f2d1 100644
--- a/gdb/.gitignore
+++ b/gdb/.gitignore
@@ -21,7 +21,6 @@ 
 /jv-exp.c
 /m2-exp.c
 /objc-exp.c
-/observer.h
 /observer.inc
 /p-exp.c
 /rust-exp.c
diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index a5f0f202a1..2f42d33c05 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,53 @@ 
+2017-11-07  Tom Tromey  <tom@tromey.com>
+
+	* common/observable.h: New file.
+	* observer.h (gdb_observers) <test_notification>: Remove.
+	* observer.c: Include selftest.h.
+	(test_notification): Now static.
+	(test_first_observer, test_second_observer, test_third_observer)
+	(test_first_notification_function)
+	(test_second_notification_function)
+	(test_third_notification_function): Renamed.  Now static.
+	(check_counters, observer_self_tests): New function.
+	(_initialize_observer): Register observer_self_tests.
+	* 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,
+	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): Change
+	type.
+	* record-btrace.c (record_btrace_thread_observer): Change type.
+	(_initialize_record_btrace): Initialize
+	record_btrace_thread_observer.
+	* observer.sh: Remove.
+	* observer.h: New file.
+	* observer.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.
+	* .gitignore: Remove observer.h.
+
 2018-02-08  Tom Tromey  <tom@tromey.com>
 
 	* solib.c (solib_find_1): Use std::string.
diff --git a/gdb/Makefile.in b/gdb/Makefile.in
index 0f87398fbd..67f622a5a2 100644
--- a/gdb/Makefile.in
+++ b/gdb/Makefile.in
@@ -1603,8 +1603,6 @@  generated_files = \
 	config.h \
 	gcore \
 	jit-reader.h \
-	observer.h \
-	observer.inc \
 	$(GNULIB_H) \
 	$(NAT_GENERATED_FILES)
 
@@ -1973,7 +1971,7 @@  tags: TAGS
 clean mostlyclean: $(CONFIG_CLEAN)
 	@$(MAKE) $(FLAGS_TO_PASS) DO=clean "DODIRS=$(CLEANDIRS)" subdir_do
 	rm -f *.o *.a $(ADD_FILES) *~ init.c-tmp init.l-tmp version.c-tmp
-	rm -f init.c version.c observer.h observer.inc
+	rm -f init.c version.c
 	rm -f gdb$(EXEEXT) core make.log
 	rm -f gdb[0-9]$(EXEEXT)
 	rm -f test-cp-name-parser$(EXEEXT)
@@ -2160,12 +2158,6 @@  version.c: Makefile version.in $(srcdir)/../bfd/version.h $(srcdir)/common/creat
 	$(SHELL) $(srcdir)/common/create-version.sh $(srcdir) \
 	    $(host_alias) $(target_alias) version.c
 
-observer.h: observer.sh doc/observer.texi
-	${srcdir}/observer.sh h ${srcdir}/doc/observer.texi observer.h
-
-observer.inc: observer.sh doc/observer.texi
-	${srcdir}/observer.sh inc ${srcdir}/doc/observer.texi observer.inc
-
 lint: $(LINTFILES)
 	$(LINT) $(INCLUDE_CFLAGS) $(LINTFLAGS) $(LINTFILES) \
 	   `echo $(DEPFILES) $(CONFIG_OBS) | sed 's/\.o /\.c /g'`
diff --git a/gdb/ada-lang.c b/gdb/ada-lang.c
index 0da58d9427..6f9802282e 100644
--- a/gdb/ada-lang.c
+++ b/gdb/ada-lang.c
@@ -14723,9 +14723,9 @@  DWARF attribute."),
      NULL, xcalloc, xfree);
 
   /* The ada-lang observers.  */
-  observer_attach_new_objfile (ada_new_objfile_observer);
-  observer_attach_free_objfile (ada_free_objfile_observer);
-  observer_attach_inferior_exit (ada_inferior_exit);
+  gdb::observers::new_objfile.attach (ada_new_objfile_observer);
+  gdb::observers::free_objfile.attach (ada_free_objfile_observer);
+  gdb::observers::inferior_exit.attach (ada_inferior_exit);
 
   /* Setup various context-specific data.  */
   ada_inferior_data
diff --git a/gdb/ada-tasks.c b/gdb/ada-tasks.c
index d95d8b092d..59633ea6db 100644
--- a/gdb/ada-tasks.c
+++ b/gdb/ada-tasks.c
@@ -1444,8 +1444,8 @@  _initialize_tasks (void)
   ada_tasks_inferior_data_handle = register_inferior_data ();
 
   /* Attach various observers.  */
-  observer_attach_normal_stop (ada_tasks_normal_stop_observer);
-  observer_attach_new_objfile (ada_tasks_new_objfile_observer);
+  gdb::observers::normal_stop.attach (ada_tasks_normal_stop_observer);
+  gdb::observers::new_objfile.attach (ada_tasks_new_objfile_observer);
 
   /* Some new commands provided by this module.  */
   add_info ("tasks", info_tasks_command,
diff --git a/gdb/agent.c b/gdb/agent.c
index 2b7fc8ad6f..8e5381d6f1 100644
--- a/gdb/agent.c
+++ b/gdb/agent.c
@@ -66,7 +66,7 @@  agent_new_objfile (struct objfile *objfile)
 void
 _initialize_agent (void)
 {
-  observer_attach_new_objfile (agent_new_objfile);
+  gdb::observers::new_objfile.attach (agent_new_objfile);
 
   add_setshow_enum_cmd ("agent", class_run,
 			can_use_agent_enum,
diff --git a/gdb/aix-thread.c b/gdb/aix-thread.c
index 09d5175d90..8fea74f389 100644
--- a/gdb/aix-thread.c
+++ b/gdb/aix-thread.c
@@ -1859,11 +1859,11 @@  _initialize_aix_thread (void)
   complete_target_initialization (&aix_thread_ops);
 
   /* Notice when object files get loaded and unloaded.  */
-  observer_attach_new_objfile (new_objfile);
+  gdb::observers::new_objfile.attach (new_objfile);
 
   /* Add ourselves to inferior_created event chain.
      This is needed to enable the thread target on "attach".  */
-  observer_attach_inferior_created (aix_thread_inferior_created);
+  gdb::observers::inferior_created.attach (aix_thread_inferior_created);
 
   add_setshow_boolean_cmd ("aix-thread", class_maintenance, &debug_aix_thread,
 			   _("Set debugging of AIX thread module."),
diff --git a/gdb/annotate.c b/gdb/annotate.c
index 0c70ff9553..bab1c1edf5 100644
--- a/gdb/annotate.c
+++ b/gdb/annotate.c
@@ -592,7 +592,7 @@  breakpoint_changed (struct breakpoint *b)
 void
 _initialize_annotate (void)
 {
-  observer_attach_breakpoint_created (breakpoint_changed);
-  observer_attach_breakpoint_deleted (breakpoint_changed);
-  observer_attach_breakpoint_modified (breakpoint_changed);
+  gdb::observers::breakpoint_created.attach (breakpoint_changed);
+  gdb::observers::breakpoint_deleted.attach (breakpoint_changed);
+  gdb::observers::breakpoint_modified.attach (breakpoint_changed);
 }
diff --git a/gdb/arm-tdep.c b/gdb/arm-tdep.c
index 8be0d4d063..d7d2efb8f6 100644
--- a/gdb/arm-tdep.c
+++ b/gdb/arm-tdep.c
@@ -9556,7 +9556,7 @@  _initialize_arm_tdep (void)
     = register_objfile_data_with_cleanup (NULL, arm_objfile_data_free);
 
   /* Add ourselves to objfile event chain.  */
-  observer_attach_new_objfile (arm_exidx_new_objfile);
+  gdb::observers::new_objfile.attach (arm_exidx_new_objfile);
   arm_exidx_data_key
     = register_objfile_data_with_cleanup (NULL, arm_exidx_data_free);
 
diff --git a/gdb/auto-load.c b/gdb/auto-load.c
index 30c8b89e8e..62d40c7bee 100644
--- a/gdb/auto-load.c
+++ b/gdb/auto-load.c
@@ -1568,7 +1568,7 @@  _initialize_auto_load (void)
     = register_program_space_data_with_cleanup (NULL,
 						auto_load_pspace_data_cleanup);
 
-  observer_attach_new_objfile (auto_load_new_objfile);
+  gdb::observers::new_objfile.attach (auto_load_new_objfile);
 
   add_setshow_boolean_cmd ("gdb-scripts", class_support,
 			   &auto_load_gdb_scripts, _("\
@@ -1678,7 +1678,7 @@  This options has security implications for untrusted inferiors."),
 				     show_auto_load_safe_path,
 				     auto_load_set_cmdlist_get (),
 				     auto_load_show_cmdlist_get ());
-  observer_attach_gdb_datadir_changed (auto_load_gdb_datadir_changed);
+  gdb::observers::gdb_datadir_changed.attach (auto_load_gdb_datadir_changed);
 
   cmd = add_cmd ("add-auto-load-safe-path", class_support,
 		 add_auto_load_safe_path,
diff --git a/gdb/auxv.c b/gdb/auxv.c
index 3a4d914326..0b2fca7cbc 100644
--- a/gdb/auxv.c
+++ b/gdb/auxv.c
@@ -579,7 +579,7 @@  This is information provided by the operating system at program startup."));
     = register_inferior_data_with_cleanup (NULL, auxv_inferior_data_cleanup);
 
   /* Observers used to invalidate the auxv cache when needed.  */
-  observer_attach_inferior_exit (invalidate_auxv_cache_inf);
-  observer_attach_inferior_appeared (invalidate_auxv_cache_inf);
-  observer_attach_executable_changed (invalidate_auxv_cache);
+  gdb::observers::inferior_exit.attach (invalidate_auxv_cache_inf);
+  gdb::observers::inferior_appeared.attach (invalidate_auxv_cache_inf);
+  gdb::observers::executable_changed.attach (invalidate_auxv_cache);
 }
diff --git a/gdb/break-catch-syscall.c b/gdb/break-catch-syscall.c
index 42d49387e2..99124092e7 100644
--- a/gdb/break-catch-syscall.c
+++ b/gdb/break-catch-syscall.c
@@ -632,7 +632,7 @@  _initialize_break_catch_syscall (void)
 {
   initialize_syscall_catchpoint_ops ();
 
-  observer_attach_inferior_exit (clear_syscall_counts);
+  gdb::observers::inferior_exit.attach (clear_syscall_counts);
   catch_syscall_inferior_data
     = register_inferior_data_with_cleanup (NULL,
 					   catch_syscall_inferior_data_cleanup);
diff --git a/gdb/breakpoint.c b/gdb/breakpoint.c
index 91ecca62fc..eecb567087 100644
--- a/gdb/breakpoint.c
+++ b/gdb/breakpoint.c
@@ -903,7 +903,7 @@  set_breakpoint_condition (struct breakpoint *b, const char *exp,
     }
   mark_breakpoint_modified (b);
 
-  observer_notify_breakpoint_modified (b);
+  gdb::observers::breakpoint_modified.notify (b);
 }
 
 /* Completion for the "condition" command.  */
@@ -1172,7 +1172,7 @@  breakpoint_set_commands (struct breakpoint *b,
   validate_commands_for_breakpoint (b, commands.get ());
 
   b->commands = std::move (commands);
-  observer_notify_breakpoint_modified (b);
+  gdb::observers::breakpoint_modified.notify (b);
 }
 
 /* Set the internal `silent' flag on the breakpoint.  Note that this
@@ -1186,7 +1186,7 @@  breakpoint_set_silent (struct breakpoint *b, int silent)
 
   b->silent = silent;
   if (old_silent != silent)
-    observer_notify_breakpoint_modified (b);
+    gdb::observers::breakpoint_modified.notify (b);
 }
 
 /* Set the thread for this breakpoint.  If THREAD is -1, make the
@@ -1199,7 +1199,7 @@  breakpoint_set_thread (struct breakpoint *b, int thread)
 
   b->thread = thread;
   if (old_thread != thread)
-    observer_notify_breakpoint_modified (b);
+    gdb::observers::breakpoint_modified.notify (b);
 }
 
 /* Set the task for this breakpoint.  If TASK is 0, make the
@@ -1212,7 +1212,7 @@  breakpoint_set_task (struct breakpoint *b, int task)
 
   b->task = task;
   if (old_task != task)
-    observer_notify_breakpoint_modified (b);
+    gdb::observers::breakpoint_modified.notify (b);
 }
 
 void
@@ -1269,7 +1269,7 @@  commands_command_1 (const char *arg, int from_tty,
 	 {
 	   validate_commands_for_breakpoint (b, cmd.get ());
 	   b->commands = cmd;
-	   observer_notify_breakpoint_modified (b);
+	   gdb::observers::breakpoint_modified.notify (b);
 	 }
      });
 }
@@ -2655,7 +2655,7 @@  insert_bp_location (struct bp_location *bl,
 	    {
 	      /* See also: disable_breakpoints_in_shlibs.  */
 	      bl->shlib_disabled = 1;
-	      observer_notify_breakpoint_modified (bl->owner);
+	      gdb::observers::breakpoint_modified.notify (bl->owner);
 	      if (!*disabled_breaks)
 		{
 		  fprintf_unfiltered (tmp_error_stream, 
@@ -5326,7 +5326,7 @@  bpstat_check_breakpoint_conditions (bpstat bs, ptid_t ptid)
       bs->stop = 0;
       /* Increase the hit count even though we don't stop.  */
       ++(b->hit_count);
-      observer_notify_breakpoint_modified (b);
+      gdb::observers::breakpoint_modified.notify (b);
     }	
 }
 
@@ -5481,7 +5481,7 @@  bpstat_stop_status (const address_space *aspace,
 	  if (bs->stop)
 	    {
 	      ++(b->hit_count);
-	      observer_notify_breakpoint_modified (b);
+	      gdb::observers::breakpoint_modified.notify (b);
 
 	      /* We will stop here.  */
 	      if (b->disposition == disp_disable)
@@ -7644,7 +7644,7 @@  disable_breakpoints_in_unloaded_shlib (struct so_list *solib)
 	loc->inserted = 0;
 
 	/* This may cause duplicate notifications for the same breakpoint.  */
-	observer_notify_breakpoint_modified (b);
+	gdb::observers::breakpoint_modified.notify (b);
 
 	if (!disabled_shlib_breaks)
 	  {
@@ -7727,7 +7727,7 @@  disable_breakpoints_in_freed_objfile (struct objfile *objfile)
 	}
 
       if (bp_modified)
-	observer_notify_breakpoint_modified (b);
+	gdb::observers::breakpoint_modified.notify (b);
     }
 }
 
@@ -8261,7 +8261,7 @@  install_breakpoint (int internal, std::unique_ptr<breakpoint> &&arg, int update_
     set_tracepoint_count (breakpoint_count);
   if (!internal)
     mention (b);
-  observer_notify_breakpoint_created (b);
+  gdb::observers::breakpoint_created.notify (b);
 
   if (update_gll)
     update_global_location_list (UGLL_MAY_INSERT);
@@ -10008,7 +10008,7 @@  break_range_command (const char *arg, int from_tty)
   b->loc->length = length;
 
   mention (b);
-  observer_notify_breakpoint_created (b);
+  gdb::observers::breakpoint_created.notify (b);
   update_global_location_list (UGLL_MAY_INSERT);
 }
 
@@ -11763,7 +11763,7 @@  download_tracepoint_locations (void)
       t = (struct tracepoint *) b;
       t->number_on_target = b->number;
       if (bp_location_downloaded)
-	observer_notify_breakpoint_modified (b);
+	gdb::observers::breakpoint_modified.notify (b);
     }
 }
 
@@ -13276,7 +13276,7 @@  delete_breakpoint (struct breakpoint *bpt)
      a problem in that process, we'll be asked to delete the half-created
      watchpoint.  In that case, don't announce the deletion.  */
   if (bpt->number)
-    observer_notify_breakpoint_deleted (bpt);
+    gdb::observers::breakpoint_deleted.notify (bpt);
 
   if (breakpoint_chain == bpt)
     breakpoint_chain = bpt->next;
@@ -13751,7 +13751,7 @@  update_breakpoint_locations (struct breakpoint *b,
   }
 
   if (!locations_are_equal (existing_locations, b->loc))
-    observer_notify_breakpoint_modified (b);
+    gdb::observers::breakpoint_modified.notify (b);
 }
 
 /* Find the SaL locations corresponding to the given LOCATION.
@@ -14048,7 +14048,7 @@  set_ignore_count (int bptnum, int count, int from_tty)
 			       "crossings of breakpoint %d."),
 			     count, bptnum);
 	}
-      observer_notify_breakpoint_modified (b);
+      gdb::observers::breakpoint_modified.notify (b);
       return;
     }
 
@@ -14351,7 +14351,7 @@  disable_breakpoint (struct breakpoint *bpt)
 
   update_global_location_list (UGLL_DONT_INSERT);
 
-  observer_notify_breakpoint_modified (bpt);
+  gdb::observers::breakpoint_modified.notify (bpt);
 }
 
 /* Enable or disable the breakpoint(s) or breakpoint location(s)
@@ -14477,7 +14477,7 @@  enable_breakpoint_disp (struct breakpoint *bpt, enum bpdisp disposition,
   bpt->enable_count = count;
   update_global_location_list (UGLL_MAY_INSERT);
 
-  observer_notify_breakpoint_modified (bpt);
+  gdb::observers::breakpoint_modified.notify (bpt);
 }
 
 
@@ -14957,7 +14957,7 @@  static void
 trace_pass_set_count (struct tracepoint *tp, int count, int from_tty)
 {
   tp->pass_count = count;
-  observer_notify_breakpoint_modified (tp);
+  gdb::observers::breakpoint_modified.notify (tp);
   if (from_tty)
     printf_filtered (_("Setting tracepoint %d's passcount to %d\n"),
 		     tp->number, count);
@@ -15597,9 +15597,9 @@  _initialize_breakpoint (void)
 
   initialize_breakpoint_ops ();
 
-  observer_attach_solib_unloaded (disable_breakpoints_in_unloaded_shlib);
-  observer_attach_free_objfile (disable_breakpoints_in_freed_objfile);
-  observer_attach_memory_changed (invalidate_bp_value_on_memory_change);
+  gdb::observers::solib_unloaded.attach (disable_breakpoints_in_unloaded_shlib);
+  gdb::observers::free_objfile.attach (disable_breakpoints_in_freed_objfile);
+  gdb::observers::memory_changed.attach (invalidate_bp_value_on_memory_change);
 
   breakpoint_objfile_key
     = register_objfile_data_with_cleanup (NULL, free_breakpoint_objfile_data);
@@ -16150,6 +16150,6 @@  agent-printf \"printf format string\", arg1, arg2, arg3, ..., argn\n\
 
   automatic_hardware_breakpoints = 1;
 
-  observer_attach_about_to_proceed (breakpoint_about_to_proceed);
-  observer_attach_thread_exit (remove_threaded_breakpoints);
+  gdb::observers::about_to_proceed.attach (breakpoint_about_to_proceed);
+  gdb::observers::thread_exit.attach (remove_threaded_breakpoints);
 }
diff --git a/gdb/bsd-uthread.c b/gdb/bsd-uthread.c
index fdcac41e6a..7d667aed23 100644
--- a/gdb/bsd-uthread.c
+++ b/gdb/bsd-uthread.c
@@ -554,7 +554,7 @@  _initialize_bsd_uthread (void)
 
   bsd_uthread_data = gdbarch_data_register_pre_init (bsd_uthread_init);
 
-  observer_attach_inferior_created (bsd_uthread_inferior_created);
-  observer_attach_solib_loaded (bsd_uthread_solib_loaded);
-  observer_attach_solib_unloaded (bsd_uthread_solib_unloaded);
+  gdb::observers::inferior_created.attach (bsd_uthread_inferior_created);
+  gdb::observers::solib_loaded.attach (bsd_uthread_solib_loaded);
+  gdb::observers::solib_unloaded.attach (bsd_uthread_solib_unloaded);
 }
diff --git a/gdb/cli/cli-interp.c b/gdb/cli/cli-interp.c
index 12b677fa7e..ff1e03213d 100644
--- a/gdb/cli/cli-interp.c
+++ b/gdb/cli/cli-interp.c
@@ -461,14 +461,14 @@  _initialize_cli_interp (void)
   interp_factory_register (INTERP_CONSOLE, cli_interp_factory);
 
   /* If changing this, remember to update tui-interp.c as well.  */
-  observer_attach_normal_stop (cli_on_normal_stop);
-  observer_attach_end_stepping_range (cli_on_end_stepping_range);
-  observer_attach_signal_received (cli_on_signal_received);
-  observer_attach_signal_exited (cli_on_signal_exited);
-  observer_attach_exited (cli_on_exited);
-  observer_attach_no_history (cli_on_no_history);
-  observer_attach_sync_execution_done (cli_on_sync_execution_done);
-  observer_attach_command_error (cli_on_command_error);
-  observer_attach_user_selected_context_changed
+  gdb::observers::normal_stop.attach (cli_on_normal_stop);
+  gdb::observers::end_stepping_range.attach (cli_on_end_stepping_range);
+  gdb::observers::signal_received.attach (cli_on_signal_received);
+  gdb::observers::signal_exited.attach (cli_on_signal_exited);
+  gdb::observers::exited.attach (cli_on_exited);
+  gdb::observers::no_history.attach (cli_on_no_history);
+  gdb::observers::sync_execution_done.attach (cli_on_sync_execution_done);
+  gdb::observers::command_error.attach (cli_on_command_error);
+  gdb::observers::user_selected_context_changed.attach
     (cli_on_user_selected_context_changed);
 }
diff --git a/gdb/cli/cli-setshow.c b/gdb/cli/cli-setshow.c
index f74a8acf36..6c144ffa70 100644
--- a/gdb/cli/cli-setshow.c
+++ b/gdb/cli/cli-setshow.c
@@ -511,20 +511,20 @@  do_set_command (const char *arg, int from_tty, struct cmd_list_element *c)
 	case var_filename:
 	case var_optional_filename:
 	case var_enum:
-	  observer_notify_command_param_changed (name, *(char **) c->var);
+	  gdb::observers::command_param_changed.notify (name, *(char **) c->var);
 	  break;
 	case var_boolean:
 	  {
 	    const char *opt = *(int *) c->var ? "on" : "off";
 
-	    observer_notify_command_param_changed (name, opt);
+	    gdb::observers::command_param_changed.notify (name, opt);
 	  }
 	  break;
 	case var_auto_boolean:
 	  {
 	    const char *s = auto_boolean_enums[*(enum auto_boolean *) c->var];
 
-	    observer_notify_command_param_changed (name, s);
+	    gdb::observers::command_param_changed.notify (name, s);
 	  }
 	  break;
 	case var_uinteger:
@@ -533,7 +533,7 @@  do_set_command (const char *arg, int from_tty, struct cmd_list_element *c)
 	    char s[64];
 
 	    xsnprintf (s, sizeof s, "%u", *(unsigned int *) c->var);
-	    observer_notify_command_param_changed (name, s);
+	    gdb::observers::command_param_changed.notify (name, s);
 	  }
 	  break;
 	case var_integer:
@@ -543,7 +543,7 @@  do_set_command (const char *arg, int from_tty, struct cmd_list_element *c)
 	    char s[64];
 
 	    xsnprintf (s, sizeof s, "%d", *(int *) c->var);
-	    observer_notify_command_param_changed (name, s);
+	    gdb::observers::command_param_changed.notify (name, s);
 	  }
 	  break;
 	}
diff --git a/gdb/common/observable.h b/gdb/common/observable.h
new file mode 100644
index 0000000000..118718871f
--- /dev/null
+++ b/gdb/common/observable.h
@@ -0,0 +1,111 @@ 
+/* Observers
+
+   Copyright (C) 2016-2018 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#if !defined (GDB_COMMON_OBSERVABLE_H)
+#define GDB_COMMON_OBSERVABLE_H
+
+#include <algorithm>
+#include <functional>
+#include <vector>
+
+namespace gdb
+{
+
+namespace observers
+{
+
+extern unsigned int observer_debug;
+
+/* An observer is an entity which is interested in being notified
+   when GDB reaches certain states, or certain events occur in GDB.
+   The entity being observed is called the observable.  To receive
+   notifications, the observer attaches a callback to the observable.
+   One observable can have several observers.
+
+   The observer implementation is also currently not reentrant.  In
+   particular, it is therefore not possible to call the attach or
+   detach routines during a notification.  */
+
+template<typename... T>
+class observable
+{
+public:
+
+  typedef std::function<void(T...)> func_type;
+
+  /* The return type of attach, which can be passed to detach to
+     remove a listener.  */
+  typedef size_t token_type;
+
+  /* A "null" value of token_type that can be used as a
+     sentinel.  */
+  static constexpr const token_type null_token = size_t (-1);
+
+  explicit observable (const char *name)
+    : m_count (0),
+      m_name (name)
+  {
+  }
+
+  DISABLE_COPY_AND_ASSIGN (observable);
+
+  /* Attach F as an observable to this observable.  A token is
+     returned which can be used to later remove F.  */
+  token_type attach (const func_type &f)
+  {
+    m_observers.emplace_back (m_count, f);
+    return m_count++;
+  }
+
+  /* Remove an observer from this observable.  F is the token that was
+     previously returned by "attach".  */
+  void detach (const token_type &f)
+  {
+    auto iter = std::remove_if (m_observers.begin (),
+				m_observers.end (),
+				[=] (const std::pair<size_t, func_type> &e)
+				{
+				  return e.first == f;
+				});
+
+    m_observers.erase (iter, m_observers.end ());
+  }
+
+  /* Notify all observables that are attached to this observer.  */
+  void notify (T... args) const
+  {
+    if (observer_debug)
+      fprintf_unfiltered (gdb_stdlog, "observer %s notify() called\n",
+			  m_name);
+    for (auto &&e : m_observers)
+      e.second (args...);
+  }
+
+private:
+
+  size_t m_count;
+  std::vector<std::pair<size_t, func_type>> m_observers;
+  const char *m_name;
+};
+
+} /* namespace observers */
+
+} /* namespace gdb */
+
+#endif /* GDB_COMMON_OBSERVABLE_H */
diff --git a/gdb/corefile.c b/gdb/corefile.c
index abf9ea675d..fe9348c920 100644
--- a/gdb/corefile.c
+++ b/gdb/corefile.c
@@ -408,7 +408,7 @@  write_memory_with_notification (CORE_ADDR memaddr, const bfd_byte *myaddr,
 				ssize_t len)
 {
   write_memory (memaddr, myaddr, len);
-  observer_notify_memory_changed (current_inferior (), memaddr, len, myaddr);
+  gdb::observers::memory_changed.notify (current_inferior (), memaddr, len, myaddr);
 }
 
 /* Store VALUE at ADDR in the inferior as a LEN-byte unsigned
diff --git a/gdb/doc/ChangeLog b/gdb/doc/ChangeLog
index 375f24dabb..0172797571 100644
--- a/gdb/doc/ChangeLog
+++ b/gdb/doc/ChangeLog
@@ -1,3 +1,7 @@ 
+2017-11-04  Tom Tromey  <tom@tromey.com>
+
+	* observer.texi: Remove.
+
 2018-01-15  Szabolcs Nagy  <szabolcs.nagy@arm.com>
 
 	* gdb.texinfo (gdb-add-index man): Add pindex.
diff --git a/gdb/doc/observer.texi b/gdb/doc/observer.texi
deleted file mode 100644
index 8ab8da709d..0000000000
--- a/gdb/doc/observer.texi
+++ /dev/null
@@ -1,313 +0,0 @@ 
-@c -*-texinfo-*-
-
-@c This file is part of the GDB manual.
-@c
-@c Copyright (C) 2003-2018 Free Software Foundation, Inc.
-@c
-@c See the file gdbint.texinfo for copying conditions.
-@c
-@c Also, the @deftypefun lines from this file are processed into a
-@c header file during the GDB build process.  Permission is granted
-@c to redistribute and/or modify those lines under the terms of the
-@c GNU General Public License as published by the Free Software
-@c Foundation; either version 3 of the License, or (at your option)
-@c any later version.
-
-@node GDB Observers
-@appendix @value{GDBN} Currently available observers
-
-@section Implementation rationale
-@cindex observers implementation rationale
-
-An @dfn{observer} is an entity which is interested in being notified
-when GDB reaches certain states, or certain events occur in GDB.
-The entity being observed is called the @dfn{subject}.  To receive
-notifications, the observer attaches a callback to the subject.
-One subject can have several observers.
-
-@file{observer.c} implements an internal generic low-level event
-notification mechanism.  This generic event notification mechanism is
-then re-used to implement the exported high-level notification
-management routines for all possible notifications.
-
-The current implementation of the generic observer provides support
-for contextual data.  This contextual data is given to the subject
-when attaching the callback.  In return, the subject will provide
-this contextual data back to the observer as a parameter of the
-callback.
-
-Note that the current support for the contextual data is only partial,
-as it lacks a mechanism that would deallocate this data when the
-callback is detached.  This is not a problem so far, as this contextual
-data is only used internally to hold a function pointer.  Later on, if
-a certain observer needs to provide support for user-level contextual
-data, then the generic notification mechanism will need to be
-enhanced to allow the observer to provide a routine to deallocate the
-data when attaching the callback.
-
-The observer implementation is also currently not reentrant.
-In particular, it is therefore not possible to call the attach
-or detach routines during a notification.
-
-@section Debugging
-Observer notifications can be traced using the command @samp{set debug
-observer 1} (@pxref{Debugging Output, , Optional messages about
-internal happenings, gdb, Debugging with @var{GDBN}}).
-
-@section @code{normal_stop} Notifications
-@cindex @code{normal_stop} observer
-@cindex notification about inferior execution stop
-
-@value{GDBN} notifies all @code{normal_stop} observers when the
-inferior execution has just stopped, the associated messages and
-annotations have been printed, and the control is about to be returned
-to the user.
-
-Note that the @code{normal_stop} notification is not emitted when
-the execution stops due to a breakpoint, and this breakpoint has
-a condition that is not met.  If the breakpoint has any associated
-commands list, the commands are executed after the notification
-is emitted.
-
-The following interfaces are available to manage observers:
-
-@deftypefun extern struct observer *observer_attach_@var{event} (observer_@var{event}_ftype *@var{f})
-Using the function @var{f}, create an observer that is notified when
-ever @var{event} occurs, return the observer.
-@end deftypefun
-
-@deftypefun extern void observer_detach_@var{event} (struct observer *@var{observer});
-Remove @var{observer} from the list of observers to be notified when
-@var{event} occurs.
-@end deftypefun
-
-@deftypefun extern void observer_notify_@var{event} (void);
-Send a notification to all @var{event} observers.
-@end deftypefun
-
-The following observable events are defined:
-
-@deftypefun void normal_stop (struct bpstats *@var{bs}, int @var{print_frame})
-The inferior has stopped for real.  The  @var{bs} argument describes
-the breakpoints were are stopped at, if any.  Second argument
-@var{print_frame} non-zero means display the location where the
-inferior has stopped.
-@end deftypefun
-
-@deftypefun void signal_received (enum gdb_signal @var{siggnal})
-The inferior was stopped by a signal.
-@end deftypefun
-
-@deftypefun void end_stepping_range (void)
-We are done with a step/next/si/ni command.
-@end deftypefun
-
-@deftypefun void signal_exited (enum gdb_signal @var{siggnal})
-The inferior was terminated by a signal.
-@end deftypefun
-
-@deftypefun void exited (int @var{exitstatus})
-The inferior program is finished.
-@end deftypefun
-
-@deftypefun void no_history (void)
-Reverse execution: target ran out of history info.
-@end deftypefun
-
-@deftypefun void sync_execution_done (void)
-A synchronous command finished.
-@end deftypefun
-
-@deftypefun void command_error (void)
-An error was caught while executing a command.
-@end deftypefun
-
-@deftypefun void target_changed (struct target_ops *@var{target})
-The target's register contents have changed.
-@end deftypefun
-
-@deftypefun void executable_changed (void)
-The executable being debugged by GDB has changed: The user decided
-to debug a different program, or the program he was debugging has
-been modified since being loaded by the debugger (by being recompiled,
-for instance).
-@end deftypefun
-
-@deftypefun void inferior_created (struct target_ops *@var{objfile}, int @var{from_tty})
-@value{GDBN} has just connected to an inferior.  For @samp{run},
-@value{GDBN} calls this observer while the inferior is still stopped
-at the entry-point instruction.  For @samp{attach} and @samp{core},
-@value{GDBN} calls this observer immediately after connecting to the
-inferior, and before any information on the inferior has been printed.
-@end deftypefun
-
-@deftypefun void record_changed (struct inferior *@var{inferior}, int @var{started}, const char *@var{method}, const char *@var{format})
-The status of process record for inferior @var{inferior} in
-@value{GDBN} has changed.  The process record is started if
-@var{started} is true, and the process record is stopped if
-@var{started} is false.
-
-When @var{started} is true, @var{method} indicates the short name of the method
-used for recording.  If the method supports multiple formats, @var{format}
-indicates which one is being used, otherwise it is NULL.  When @var{started} is
-false, they are both NULL.
-@end deftypefun
-
-@deftypefun void solib_loaded (struct so_list *@var{solib})
-The shared library specified by @var{solib} has been loaded.  Note that
-when @value{GDBN} calls this observer, the library's symbols probably
-haven't been loaded yet.
-@end deftypefun
-
-@deftypefun void solib_unloaded (struct so_list *@var{solib})
-The shared library specified by @var{solib} has been unloaded.
-Note that when @value{GDBN} calls this observer, the library's
-symbols have not been unloaded yet, and thus are still available.
-@end deftypefun
-
-@deftypefun void new_objfile (struct objfile *@var{objfile})
-The symbol file specified by @var{objfile} has been loaded.
-Called with @var{objfile} equal to @code{NULL} to indicate
-previously loaded symbol table data has now been invalidated.
-@end deftypefun
-
-@deftypefun void free_objfile (struct objfile *@var{objfile})
-The object file specified by @var{objfile} is about to be freed.
-@end deftypefun
-
-@deftypefun void new_thread (struct thread_info *@var{t})
-The thread specified by @var{t} has been created.
-@end deftypefun
-
-@deftypefun void thread_exit (struct thread_info *@var{t}, int @var{silent})
-The thread specified by @var{t} has exited.  The @var{silent} argument
-indicates that @value{GDBN} is removing the thread from its tables
-without wanting to notify the user about it.
-@end deftypefun
-
-@deftypefun void thread_stop_requested (ptid_t @var{ptid})
-An explicit stop request was issued to @var{ptid}.  If @var{ptid}
-equals @var{minus_one_ptid}, the request applied to all threads.  If
-@code{ptid_is_pid(ptid)} returns true, the request applied to all
-threads of the process pointed at by @var{ptid}.  Otherwise, the
-request applied to the single thread pointed at by @var{ptid}.
-@end deftypefun
-
-@deftypefun void target_resumed (ptid_t @var{ptid})
-The target was resumed.  The @var{ptid} parameter specifies which
-thread was resume, and may be RESUME_ALL if all threads are resumed.
-@end deftypefun
-
-@deftypefun void about_to_proceed (void)
-The target is about to be proceeded.
-@end deftypefun
-
-@deftypefun void breakpoint_created (struct breakpoint *@var{b})
-A new breakpoint @var{b} has been created.
-@end deftypefun
-
-@deftypefun void breakpoint_deleted (struct breakpoint *@var{b})
-A breakpoint has been destroyed.  The argument @var{b} is the
-pointer to the destroyed breakpoint.
-@end deftypefun
-
-@deftypefun void breakpoint_modified (struct breakpoint *@var{b})
-A breakpoint has been modified in some way.  The argument @var{b}
-is the modified breakpoint.
-@end deftypefun
-
-@deftypefun void traceframe_changed (int @var{tfnum}, int @var{tpnum})
-The trace frame is changed to @var{tfnum} (e.g., by using the
-@code{tfind} command).  If @var{tfnum} is negative, it means
-@value{GDBN} resumes live debugging.  The number of the tracepoint
-associated with this traceframe is @var{tpnum}.
-@end deftypefun
-
-@deftypefun void architecture_changed (struct gdbarch *@var{newarch})
-The current architecture has changed.  The argument @var{newarch} is
-a pointer to the new architecture.
-@end deftypefun
-
-@deftypefun void thread_ptid_changed (ptid_t @var{old_ptid}, ptid_t @var{new_ptid})
-The thread's ptid has changed.  The @var{old_ptid} parameter specifies
-the old value, and @var{new_ptid} specifies the new value.
-@end deftypefun
-
-@deftypefun void inferior_added (struct inferior *@var{inf})
-The inferior @var{inf} has been added to the list of inferiors.  At
-this point, it might not be associated with any process.
-@end deftypefun
-
-@deftypefun void inferior_appeared (struct inferior *@var{inf})
-The inferior identified by @var{inf} has been attached to a process.
-@end deftypefun
-
-@deftypefun void inferior_exit (struct inferior *@var{inf})
-Either the inferior associated with @var{inf} has been detached from the
-process, or the process has exited.
-@end deftypefun
-
-@deftypefun void inferior_removed (struct inferior *@var{inf})
-The inferior @var{inf} has been removed from the list of inferiors.
-This method is called immediately before freeing @var{inf}.
-@end deftypefun
-
-@deftypefun void memory_changed (struct inferior *@var{inferior}, CORE_ADDR @var{addr}, ssize_t @var{len}, const bfd_byte *@var{data})
-Bytes from @var{data} to @var{data} + @var{len} have been written
-to the @var{inferior} at @var{addr}.
-@end deftypefun
-
-@deftypefun void before_prompt (const char *@var{current_prompt})
-Called before a top-level prompt is displayed.  @var{current_prompt} is
-the current top-level prompt.
-@end deftypefun
-
-@deftypefun void gdb_datadir_changed (void)
-Variable gdb_datadir has been set.  The value may not necessarily change.
-@end deftypefun
-
-@deftypefun void command_param_changed (const char *@var{param}, const char *@var{value})
-The parameter of some @code{set} commands in console are changed.  This
-method is called after a command @code{set @var{param} @var{value}}.
-@var{param} is the parameter of @code{set} command, and @var{value}
-is the value of changed parameter.
-@end deftypefun
-
-@deftypefun void tsv_created (const struct trace_state_variable *@var{tsv})
-The new trace state variable @var{tsv} is created.
-@end deftypefun
-
-@deftypefun void tsv_deleted (const struct trace_state_variable *@var{tsv})
-The trace state variable @var{tsv} is deleted.  If @var{tsv} is
-@code{NULL}, all trace state variables are deleted.
-@end deftypefun
-
-@deftypefun void tsv_modified (const struct trace_state_variable *@var{tsv})
-The trace state value @var{tsv} is modified.
-@end deftypefun
-
-@deftypefun void inferior_call_pre (ptid_t @var{thread}, CORE_ADDR @var{address})
-An inferior function at @var{address} is about to be called in thread
-@var{thread}.
-@end deftypefun
-
-@deftypefun void inferior_call_post (ptid_t @var{thread}, CORE_ADDR @var{address})
-The inferior function at @var{address} has just been called.  This observer
-is called even if the inferior exits during the call.  @var{thread} is the
-thread in which the function was called, which may be different from the
-current thread.
-@end deftypefun
-
-@deftypefun void register_changed (struct frame_info *@var{frame}, int @var{regnum})
-A register in the inferior has been modified by the @value{GDBN} user.
-@end deftypefun
-
-@deftypefun void test_notification (int @var{somearg})
-This observer is used for internal testing.  Do not use.  
-See testsuite/gdb.gdb/observer.exp.
-@end deftypefun
-
-@deftypefun void user_selected_context_changed (user_selected_what @var{selection})
-The user-selected inferior, thread and/or frame has changed.  The user_select_what
-flag specifies if the inferior, thread and/or frame has changed.
-@end deftypefun
diff --git a/gdb/dummy-frame.c b/gdb/dummy-frame.c
index db8ba1b8e0..099eac8f27 100644
--- a/gdb/dummy-frame.c
+++ b/gdb/dummy-frame.c
@@ -424,5 +424,5 @@  _initialize_dummy_frame (void)
 	   _("Print the contents of the internal dummy-frame stack."),
 	   &maintenanceprintlist);
 
-  observer_attach_inferior_created (cleanup_dummy_frames);
+  gdb::observers::inferior_created.attach (cleanup_dummy_frames);
 }
diff --git a/gdb/event-loop.c b/gdb/event-loop.c
index 7934ab4c82..82b6129939 100644
--- a/gdb/event-loop.c
+++ b/gdb/event-loop.c
@@ -382,7 +382,7 @@  start_event_loop (void)
 	     get around to resetting the prompt, which leaves readline
 	     in a messed-up state.  Reset it here.  */
 	  current_ui->prompt_state = PROMPT_NEEDED;
-	  observer_notify_command_error ();
+	  gdb::observers::command_error.notify ();
 	  /* This call looks bizarre, but it is required.  If the user
 	     entered a command that caused an error,
 	     after_char_processing_hook won't be called from
diff --git a/gdb/event-top.c b/gdb/event-top.c
index 0c1528e5eb..88d7a35a9c 100644
--- a/gdb/event-top.c
+++ b/gdb/event-top.c
@@ -428,7 +428,7 @@  top_level_prompt (void)
 
   /* Give observers a chance of changing the prompt.  E.g., the python
      `gdb.prompt_hook' is installed as an observer.  */
-  observer_notify_before_prompt (get_prompt ());
+  gdb::observers::before_prompt.notify (get_prompt ());
 
   prompt = get_prompt ();
 
diff --git a/gdb/exec.c b/gdb/exec.c
index c8c32ecc27..be663cef20 100644
--- a/gdb/exec.c
+++ b/gdb/exec.c
@@ -381,7 +381,7 @@  exec_file_attach (const char *filename, int from_tty)
     }
 
   bfd_cache_close_all ();
-  observer_notify_executable_changed ();
+  gdb::observers::executable_changed.notify ();
 }
 
 /*  Process the first arg in ARGS as the new exec file.
diff --git a/gdb/extension.c b/gdb/extension.c
index 224b05c7ed..c597f9f402 100644
--- a/gdb/extension.c
+++ b/gdb/extension.c
@@ -944,5 +944,5 @@  ext_lang_before_prompt (const char *current_gdb_prompt)
 void
 _initialize_extension (void)
 {
-  observer_attach_before_prompt (ext_lang_before_prompt);
+  gdb::observers::before_prompt.attach (ext_lang_before_prompt);
 }
diff --git a/gdb/frame.c b/gdb/frame.c
index 1384ecca4f..e5debe9011 100644
--- a/gdb/frame.c
+++ b/gdb/frame.c
@@ -2924,7 +2924,7 @@  _initialize_frame (void)
 
   frame_stash_create ();
 
-  observer_attach_target_changed (frame_observer_target_changed);
+  gdb::observers::target_changed.attach (frame_observer_target_changed);
 
   add_prefix_cmd ("backtrace", class_maintenance, set_backtrace_cmd, _("\
 Set backtrace specific variables.\n\
diff --git a/gdb/gdbarch.c b/gdb/gdbarch.c
index fe3c12e295..3af5faa6e5 100644
--- a/gdb/gdbarch.c
+++ b/gdb/gdbarch.c
@@ -5457,7 +5457,7 @@  set_target_gdbarch (struct gdbarch *new_gdbarch)
   gdb_assert (new_gdbarch != NULL);
   gdb_assert (new_gdbarch->initialized_p);
   current_inferior ()->gdbarch = new_gdbarch;
-  observer_notify_architecture_changed (new_gdbarch);
+  gdb::observers::architecture_changed.notify (new_gdbarch);
   registers_changed ();
 }
 
diff --git a/gdb/guile/scm-breakpoint.c b/gdb/guile/scm-breakpoint.c
index 642eefd71e..a4106c92c5 100644
--- a/gdb/guile/scm-breakpoint.c
+++ b/gdb/guile/scm-breakpoint.c
@@ -1327,8 +1327,8 @@  gdbscm_initialize_breakpoints (void)
   scm_set_smob_free (breakpoint_smob_tag, bpscm_free_breakpoint_smob);
   scm_set_smob_print (breakpoint_smob_tag, bpscm_print_breakpoint_smob);
 
-  observer_attach_breakpoint_created (bpscm_breakpoint_created);
-  observer_attach_breakpoint_deleted (bpscm_breakpoint_deleted);
+  gdb::observers::breakpoint_created.attach (bpscm_breakpoint_created);
+  gdb::observers::breakpoint_deleted.attach (bpscm_breakpoint_deleted);
 
   gdbscm_define_integer_constants (breakpoint_integer_constants, 1);
   gdbscm_define_functions (breakpoint_functions, 1);
diff --git a/gdb/infcall.c b/gdb/infcall.c
index 8b75297251..48c2481473 100644
--- a/gdb/infcall.c
+++ b/gdb/infcall.c
@@ -906,7 +906,7 @@  call_function_by_hand_dummy (struct value *function,
       target_values_type = values_type;
     }
 
-  observer_notify_inferior_call_pre (inferior_ptid, funaddr);
+  gdb::observers::inferior_call_pre.notify (inferior_ptid, funaddr);
 
   /* Determine the location of the breakpoint (and possibly other
      stuff) that the called function will return to.  The SPARC, for a
@@ -1186,7 +1186,7 @@  call_function_by_hand_dummy (struct value *function,
 
     e = run_inferior_call (sm, tp, real_pc);
 
-    observer_notify_inferior_call_post (call_thread_ptid, funaddr);
+    gdb::observers::inferior_call_post.notify (call_thread_ptid, funaddr);
 
     tp = find_thread_ptid (call_thread_ptid);
     if (tp != NULL)
diff --git a/gdb/infcmd.c b/gdb/infcmd.c
index 3879df3f5a..5f95ffba01 100644
--- a/gdb/infcmd.c
+++ b/gdb/infcmd.c
@@ -498,7 +498,7 @@  post_create_inferior (struct target_ops *target, int from_tty)
      if the now pushed target supports hardware watchpoints.  */
   breakpoint_re_set ();
 
-  observer_notify_inferior_created (target, from_tty);
+  gdb::observers::inferior_created.notify (target, from_tty);
 }
 
 /* Kill the inferior if already running.  This function is designed
diff --git a/gdb/inferior.c b/gdb/inferior.c
index 38b7369275..91401b7878 100644
--- a/gdb/inferior.c
+++ b/gdb/inferior.c
@@ -109,7 +109,7 @@  add_inferior_silent (int pid)
       last->next = inf;
     }
 
-  observer_notify_inferior_added (inf);
+  gdb::observers::inferior_added.notify (inf);
 
   if (pid != 0)
     inferior_appeared (inf, pid);
@@ -176,7 +176,7 @@  delete_inferior (struct inferior *todel)
   else
     inferior_list = inf->next;
 
-  observer_notify_inferior_removed (inf);
+  gdb::observers::inferior_removed.notify (inf);
 
   /* If this program space is rendered useless, remove it. */
   if (program_space_empty_p (inf->pspace))
@@ -206,7 +206,7 @@  exit_inferior_1 (struct inferior *inftoex, int silent)
 
   iterate_over_threads (delete_thread_of_inferior, &arg);
 
-  observer_notify_inferior_exit (inf);
+  gdb::observers::inferior_exit.notify (inf);
 
   inf->pid = 0;
   inf->fake_pid_p = 0;
@@ -282,7 +282,7 @@  inferior_appeared (struct inferior *inf, int pid)
   inf->has_exit_code = 0;
   inf->exit_code = 0;
 
-  observer_notify_inferior_appeared (inf);
+  gdb::observers::inferior_appeared.notify (inf);
 }
 
 void
@@ -711,7 +711,7 @@  inferior_command (const char *args, int from_tty)
 	  switch_to_thread (tp->ptid);
 	}
 
-      observer_notify_user_selected_context_changed
+      gdb::observers::user_selected_context_changed.notify
 	(USER_SELECTED_INFERIOR
 	 | USER_SELECTED_THREAD
 	 | USER_SELECTED_FRAME);
@@ -722,7 +722,8 @@  inferior_command (const char *args, int from_tty)
       switch_to_thread (null_ptid);
       set_current_program_space (inf->pspace);
 
-      observer_notify_user_selected_context_changed (USER_SELECTED_INFERIOR);
+      gdb::observers::user_selected_context_changed.notify
+	(USER_SELECTED_INFERIOR);
     }
 }
 
diff --git a/gdb/inflow.c b/gdb/inflow.c
index d971543a28..2c660b146a 100644
--- a/gdb/inflow.c
+++ b/gdb/inflow.c
@@ -989,7 +989,7 @@  _initialize_inflow (void)
   /* OK, figure out whether we have job control.  */
   have_job_control ();
 
-  observer_attach_inferior_exit (inflow_inferior_exit);
+  gdb::observers::inferior_exit.attach (inflow_inferior_exit);
 
   inflow_inferior_data
     = register_inferior_data_with_cleanup (NULL, inflow_inferior_data_cleanup);
diff --git a/gdb/infrun.c b/gdb/infrun.c
index 45fe36a717..87071bba29 100644
--- a/gdb/infrun.c
+++ b/gdb/infrun.c
@@ -2903,7 +2903,7 @@  clear_proceed_status (int step)
       inferior->control.stop_soon = NO_STOP_QUIETLY;
     }
 
-  observer_notify_about_to_proceed ();
+  gdb::observers::about_to_proceed.notify ();
 }
 
 /* Returns true if TP is still stopped at a breakpoint that needs
@@ -3820,7 +3820,7 @@  check_curr_ui_sync_execution_done (void)
       && !gdb_in_secondary_prompt_p (ui))
     {
       target_terminal::ours ();
-      observer_notify_sync_execution_done ();
+      gdb::observers::sync_execution_done.notify ();
       ui_register_input_event_handler (ui);
     }
 }
@@ -5073,7 +5073,7 @@  handle_inferior_event_1 (struct execution_control_state *ecs)
 	  /* Support the --return-child-result option.  */
 	  return_child_result_value = ecs->ws.value.integer;
 
-	  observer_notify_exited (ecs->ws.value.integer);
+	  gdb::observers::exited.notify (ecs->ws.value.integer);
 	}
       else
 	{
@@ -5102,7 +5102,7 @@  handle_inferior_event_1 (struct execution_control_state *ecs)
 Cannot fill $_exitsignal with the correct signal number.\n"));
 	    }
 
-	  observer_notify_signal_exited (ecs->ws.value.sig);
+	  gdb::observers::signal_exited.notify (ecs->ws.value.sig);
 	}
 
       gdb_flush (gdb_stdout);
@@ -5396,7 +5396,7 @@  Cannot fill $_exitsignal with the correct signal number.\n"));
       if (handle_stop_requested (ecs))
 	return;
 
-      observer_notify_no_history ();
+      gdb::observers::no_history.notify ();
       stop_waiting (ecs);
       return;
     }
@@ -6100,7 +6100,7 @@  handle_signal_stop (struct execution_control_state *ecs)
 	{
 	  /* The signal table tells us to print about this signal.  */
 	  target_terminal::ours_for_output ();
-	  observer_notify_signal_received (ecs->event_thread->suspend.stop_signal);
+	  gdb::observers::signal_received.notify (ecs->event_thread->suspend.stop_signal);
 	  target_terminal::inferior ();
 	}
 
@@ -8209,7 +8209,7 @@  normal_stop (void)
   update_thread_list ();
 
   if (last.kind == TARGET_WAITKIND_STOPPED && stopped_by_random_signal)
-    observer_notify_signal_received (inferior_thread ()->suspend.stop_signal);
+    gdb::observers::signal_received.notify (inferior_thread ()->suspend.stop_signal);
 
   /* As with the notification of thread events, we want to delay
      notifying the user that we've switched thread context until
@@ -8334,10 +8334,10 @@  normal_stop (void)
   /* Notify observers about the stop.  This is where the interpreters
      print the stop event.  */
   if (!ptid_equal (inferior_ptid, null_ptid))
-    observer_notify_normal_stop (inferior_thread ()->control.stop_bpstat,
+    gdb::observers::normal_stop.notify (inferior_thread ()->control.stop_bpstat,
 				 stop_print_frame);
   else
-    observer_notify_normal_stop (NULL, stop_print_frame);
+    gdb::observers::normal_stop.notify (NULL, stop_print_frame);
 
   annotate_stopped ();
 
@@ -9442,10 +9442,10 @@  enabled by default on some platforms."),
   inferior_ptid = null_ptid;
   target_last_wait_ptid = minus_one_ptid;
 
-  observer_attach_thread_ptid_changed (infrun_thread_ptid_changed);
-  observer_attach_thread_stop_requested (infrun_thread_stop_requested);
-  observer_attach_thread_exit (infrun_thread_thread_exit);
-  observer_attach_inferior_exit (infrun_inferior_exit);
+  gdb::observers::thread_ptid_changed.attach (infrun_thread_ptid_changed);
+  gdb::observers::thread_stop_requested.attach (infrun_thread_stop_requested);
+  gdb::observers::thread_exit.attach (infrun_thread_thread_exit);
+  gdb::observers::inferior_exit.attach (infrun_inferior_exit);
 
   /* Explicitly create without lookup, since that tries to create a
      value with a void typed value, and when we get here, gdbarch
diff --git a/gdb/jit.c b/gdb/jit.c
index 01ead4577f..e9ab6ffdb5 100644
--- a/gdb/jit.c
+++ b/gdb/jit.c
@@ -1507,9 +1507,9 @@  _initialize_jit (void)
 			     show_jit_debug,
 			     &setdebuglist, &showdebuglist);
 
-  observer_attach_inferior_created (jit_inferior_created);
-  observer_attach_inferior_exit (jit_inferior_exit_hook);
-  observer_attach_breakpoint_deleted (jit_breakpoint_deleted);
+  gdb::observers::inferior_created.attach (jit_inferior_created);
+  gdb::observers::inferior_exit.attach (jit_inferior_exit_hook);
+  gdb::observers::breakpoint_deleted.attach (jit_breakpoint_deleted);
 
   jit_objfile_data =
     register_objfile_data_with_cleanup (NULL, free_objfile_data);
diff --git a/gdb/linux-tdep.c b/gdb/linux-tdep.c
index d54e56ce8d..1427a608a6 100644
--- a/gdb/linux-tdep.c
+++ b/gdb/linux-tdep.c
@@ -2519,8 +2519,8 @@  _initialize_linux_tdep (void)
   linux_inferior_data
     = register_inferior_data_with_cleanup (NULL, linux_inferior_data_cleanup);
   /* Observers used to invalidate the cache when needed.  */
-  observer_attach_inferior_exit (invalidate_linux_cache_inf);
-  observer_attach_inferior_appeared (invalidate_linux_cache_inf);
+  gdb::observers::inferior_exit.attach (invalidate_linux_cache_inf);
+  gdb::observers::inferior_appeared.attach (invalidate_linux_cache_inf);
 
   add_setshow_boolean_cmd ("use-coredump-filter", class_files,
 			   &use_coredump_filter, _("\
diff --git a/gdb/linux-thread-db.c b/gdb/linux-thread-db.c
index 794c97b48a..f989592256 100644
--- a/gdb/linux-thread-db.c
+++ b/gdb/linux-thread-db.c
@@ -993,7 +993,7 @@  thread_db_new_objfile (struct objfile *objfile)
   if (objfile != NULL
       /* libpthread with separate debug info has its debug info file already
 	 loaded (and notified without successful thread_db initialization)
-	 the time observer_notify_new_objfile is called for the library itself.
+	 the time gdb::observers::new_objfile.notify is called for the library itself.
 	 Static executables have their separate debug info loaded already
 	 before the inferior has started.  */
       && objfile->separate_debug_objfile_backlink == NULL
@@ -1781,10 +1781,10 @@  Usage: info auto-load libthread-db"),
 	   auto_load_info_cmdlist_get ());
 
   /* Add ourselves to objfile event chain.  */
-  observer_attach_new_objfile (thread_db_new_objfile);
+  gdb::observers::new_objfile.attach (thread_db_new_objfile);
 
   /* Add ourselves to inferior_created event chain.
      This is needed to handle debugging statically linked programs where
      the new_objfile observer won't get called for libpthread.  */
-  observer_attach_inferior_created (thread_db_inferior_created);
+  gdb::observers::inferior_created.attach (thread_db_inferior_created);
 }
diff --git a/gdb/m68k-linux-tdep.c b/gdb/m68k-linux-tdep.c
index e26ceab513..93976563bb 100644
--- a/gdb/m68k-linux-tdep.c
+++ b/gdb/m68k-linux-tdep.c
@@ -426,5 +426,5 @@  _initialize_m68k_linux_tdep (void)
 {
   gdbarch_register_osabi (bfd_arch_m68k, 0, GDB_OSABI_LINUX,
 			  m68k_linux_init_abi);
-  observer_attach_inferior_created (m68k_linux_inferior_created);
+  gdb::observers::inferior_created.attach (m68k_linux_inferior_created);
 }
diff --git a/gdb/mi/mi-cmd-break.c b/gdb/mi/mi-cmd-break.c
index 243a9d03a8..cb4d0eb030 100644
--- a/gdb/mi/mi-cmd-break.c
+++ b/gdb/mi/mi-cmd-break.c
@@ -84,7 +84,7 @@  setup_breakpoint_reporting (void)
 {
   if (! mi_breakpoint_observers_installed)
     {
-      observer_attach_breakpoint_created (breakpoint_notify);
+      gdb::observers::breakpoint_created.attach (breakpoint_notify);
       mi_breakpoint_observers_installed = 1;
     }
 
@@ -394,7 +394,7 @@  mi_cmd_break_passcount (const char *command, char **argv, int argc)
   if (t)
     {
       t->pass_count = p;
-      observer_notify_breakpoint_modified (t);
+      gdb::observers::breakpoint_modified.notify (t);
     }
   else
     {
diff --git a/gdb/mi/mi-interp.c b/gdb/mi/mi-interp.c
index 2ec1d693b1..6a26fb6117 100644
--- a/gdb/mi/mi-interp.c
+++ b/gdb/mi/mi-interp.c
@@ -1353,33 +1353,33 @@  _initialize_mi_interp (void)
   interp_factory_register (INTERP_MI3, mi_interp_factory);
   interp_factory_register (INTERP_MI, mi_interp_factory);
 
-  observer_attach_signal_received (mi_on_signal_received);
-  observer_attach_end_stepping_range (mi_on_end_stepping_range);
-  observer_attach_signal_exited (mi_on_signal_exited);
-  observer_attach_exited (mi_on_exited);
-  observer_attach_no_history (mi_on_no_history);
-  observer_attach_new_thread (mi_new_thread);
-  observer_attach_thread_exit (mi_thread_exit);
-  observer_attach_inferior_added (mi_inferior_added);
-  observer_attach_inferior_appeared (mi_inferior_appeared);
-  observer_attach_inferior_exit (mi_inferior_exit);
-  observer_attach_inferior_removed (mi_inferior_removed);
-  observer_attach_record_changed (mi_record_changed);
-  observer_attach_normal_stop (mi_on_normal_stop);
-  observer_attach_target_resumed (mi_on_resume);
-  observer_attach_solib_loaded (mi_solib_loaded);
-  observer_attach_solib_unloaded (mi_solib_unloaded);
-  observer_attach_about_to_proceed (mi_about_to_proceed);
-  observer_attach_traceframe_changed (mi_traceframe_changed);
-  observer_attach_tsv_created (mi_tsv_created);
-  observer_attach_tsv_deleted (mi_tsv_deleted);
-  observer_attach_tsv_modified (mi_tsv_modified);
-  observer_attach_breakpoint_created (mi_breakpoint_created);
-  observer_attach_breakpoint_deleted (mi_breakpoint_deleted);
-  observer_attach_breakpoint_modified (mi_breakpoint_modified);
-  observer_attach_command_param_changed (mi_command_param_changed);
-  observer_attach_memory_changed (mi_memory_changed);
-  observer_attach_sync_execution_done (mi_on_sync_execution_done);
-  observer_attach_user_selected_context_changed
+  gdb::observers::signal_received.attach (mi_on_signal_received);
+  gdb::observers::end_stepping_range.attach (mi_on_end_stepping_range);
+  gdb::observers::signal_exited.attach (mi_on_signal_exited);
+  gdb::observers::exited.attach (mi_on_exited);
+  gdb::observers::no_history.attach (mi_on_no_history);
+  gdb::observers::new_thread.attach (mi_new_thread);
+  gdb::observers::thread_exit.attach (mi_thread_exit);
+  gdb::observers::inferior_added.attach (mi_inferior_added);
+  gdb::observers::inferior_appeared.attach (mi_inferior_appeared);
+  gdb::observers::inferior_exit.attach (mi_inferior_exit);
+  gdb::observers::inferior_removed.attach (mi_inferior_removed);
+  gdb::observers::record_changed.attach (mi_record_changed);
+  gdb::observers::normal_stop.attach (mi_on_normal_stop);
+  gdb::observers::target_resumed.attach (mi_on_resume);
+  gdb::observers::solib_loaded.attach (mi_solib_loaded);
+  gdb::observers::solib_unloaded.attach (mi_solib_unloaded);
+  gdb::observers::about_to_proceed.attach (mi_about_to_proceed);
+  gdb::observers::traceframe_changed.attach (mi_traceframe_changed);
+  gdb::observers::tsv_created.attach (mi_tsv_created);
+  gdb::observers::tsv_deleted.attach (mi_tsv_deleted);
+  gdb::observers::tsv_modified.attach (mi_tsv_modified);
+  gdb::observers::breakpoint_created.attach (mi_breakpoint_created);
+  gdb::observers::breakpoint_deleted.attach (mi_breakpoint_deleted);
+  gdb::observers::breakpoint_modified.attach (mi_breakpoint_modified);
+  gdb::observers::command_param_changed.attach (mi_command_param_changed);
+  gdb::observers::memory_changed.attach (mi_memory_changed);
+  gdb::observers::sync_execution_done.attach (mi_on_sync_execution_done);
+  gdb::observers::user_selected_context_changed.attach
     (mi_user_selected_context_changed);
 }
diff --git a/gdb/mi/mi-main.c b/gdb/mi/mi-main.c
index 51d33c9e9f..4a0d675b5b 100644
--- a/gdb/mi/mi-main.c
+++ b/gdb/mi/mi-main.c
@@ -573,8 +573,8 @@  mi_cmd_thread_select (const char *command, char **argv, int argc)
   /* Notify if the thread has effectively changed.  */
   if (!ptid_equal (inferior_ptid, previous_ptid))
     {
-      observer_notify_user_selected_context_changed (USER_SELECTED_THREAD
-						     | USER_SELECTED_FRAME);
+      gdb::observers::user_selected_context_changed.notify
+	(USER_SELECTED_THREAD | USER_SELECTED_FRAME);
     }
 }
 
@@ -2024,8 +2024,8 @@  mi_execute_command (const char *cmd, int from_tty)
 
 	  if (report_change)
 	    {
-		observer_notify_user_selected_context_changed
-		  (USER_SELECTED_THREAD | USER_SELECTED_FRAME);
+	      gdb::observers::user_selected_context_changed.notify
+		(USER_SELECTED_THREAD | USER_SELECTED_FRAME);
 	    }
 	}
     }
diff --git a/gdb/objfiles.c b/gdb/objfiles.c
index 70e369b8b4..f1c56628e2 100644
--- a/gdb/objfiles.c
+++ b/gdb/objfiles.c
@@ -616,7 +616,7 @@  free_objfile_separate_debug (struct objfile *objfile)
 objfile::~objfile ()
 {
   /* First notify observers that this objfile is about to be freed.  */
-  observer_notify_free_objfile (this);
+  gdb::observers::free_objfile.notify (this);
 
   /* Free all separate debug objfiles.  */
   free_objfile_separate_debug (this);
diff --git a/gdb/observer.c b/gdb/observer.c
index 3c0ec2a2ee..d39e3e7462 100644
--- a/gdb/observer.c
+++ b/gdb/observer.c
@@ -17,199 +17,199 @@ 
    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
-/* An observer is an entity who is interested in being notified when GDB
-   reaches certain states, or certain events occur in GDB.  The entity being
-   observed is called the Subject.  To receive notifications, the observer
-   attaches a callback to the subject.  One subject can have several
-   observers.
-
-   This file implements an internal generic low-level event notification
-   mechanism based on the Observer paradigm described in the book "Design
-   Patterns".  This generic event notification mechansim is then re-used
-   to implement the exported high-level notification management routines
-   for all possible notifications.
-
-   The current implementation of the generic observer provides support
-   for contextual data.  This contextual data is given to the subject
-   when attaching the callback.  In return, the subject will provide
-   this contextual data back to the observer as a parameter of the
-   callback.
-
-   FIXME: The current support for the contextual data is only partial,
-   as it lacks a mechanism that would deallocate this data when the
-   callback is detached.  This is not a problem so far, as this contextual
-   data is only used internally to hold a function pointer.  Later on,
-   if a certain observer needs to provide support for user-level
-   contextual data, then the generic notification mechanism will need
-   need to be enhanced to allow the observer to provide a routine to
-   deallocate the data when attaching the callback.
-
-   This file is currently maintained by hand, but the long term plan
-   if the number of different notifications starts growing is to create
-   a new script (observer.sh) that would generate this file, and the
-   associated documentation.  */
-
 #include "defs.h"
 #include "observer.h"
 #include "command.h"
 #include "gdbcmd.h"
+#include "selftest.h"
 
-static unsigned int observer_debug;
-static void
-show_observer_debug (struct ui_file *file, int from_tty,
-		     struct cmd_list_element *c, const char *value)
+namespace gdb
 {
-  fprintf_filtered (file, _("Observer debugging is %s.\n"), value);
-}
-
-/* The internal generic observer.  */
 
-typedef void (generic_observer_notification_ftype) (const void *data,
-						    const void *args);
-
-struct observer
+namespace observers
 {
-  generic_observer_notification_ftype *notify;
-  /* No memory management needed for the following field for now.  */
-  void *data;
-};
-
-/* A list of observers, maintained by the subject.  A subject is
-   actually represented by its list of observers.  */
 
-struct observer_list
+unsigned int observer_debug;
+
+#define DEFINE_OBSERVER(name) decltype (name) name (# name)
+
+DEFINE_OBSERVER (normal_stop);
+DEFINE_OBSERVER (signal_received);
+DEFINE_OBSERVER (end_stepping_range);
+DEFINE_OBSERVER (signal_exited);
+DEFINE_OBSERVER (exited);
+DEFINE_OBSERVER (no_history);
+DEFINE_OBSERVER (sync_execution_done);
+DEFINE_OBSERVER (command_error);
+DEFINE_OBSERVER (target_changed);
+DEFINE_OBSERVER (executable_changed);
+DEFINE_OBSERVER (inferior_created);
+DEFINE_OBSERVER (record_changed);
+DEFINE_OBSERVER (solib_loaded);
+DEFINE_OBSERVER (solib_unloaded);
+DEFINE_OBSERVER (new_objfile);
+DEFINE_OBSERVER (free_objfile);
+DEFINE_OBSERVER (new_thread);
+DEFINE_OBSERVER (thread_exit);
+DEFINE_OBSERVER (thread_stop_requested);
+DEFINE_OBSERVER (target_resumed);
+DEFINE_OBSERVER (about_to_proceed);
+DEFINE_OBSERVER (breakpoint_created);
+DEFINE_OBSERVER (breakpoint_deleted);
+DEFINE_OBSERVER (breakpoint_modified);
+DEFINE_OBSERVER (traceframe_changed);
+DEFINE_OBSERVER (architecture_changed);
+DEFINE_OBSERVER (thread_ptid_changed);
+DEFINE_OBSERVER (inferior_added);
+DEFINE_OBSERVER (inferior_appeared);
+DEFINE_OBSERVER (inferior_exit);
+DEFINE_OBSERVER (inferior_removed);
+DEFINE_OBSERVER (memory_changed);
+DEFINE_OBSERVER (before_prompt);
+DEFINE_OBSERVER (gdb_datadir_changed);
+DEFINE_OBSERVER (command_param_changed);
+DEFINE_OBSERVER (tsv_created);
+DEFINE_OBSERVER (tsv_deleted);
+DEFINE_OBSERVER (tsv_modified);
+DEFINE_OBSERVER (inferior_call_pre);
+DEFINE_OBSERVER (inferior_call_post);
+DEFINE_OBSERVER (register_changed);
+DEFINE_OBSERVER (user_selected_context_changed);
+
+#ifdef GDB_SELF_TEST
+
+namespace selftests
 {
-  struct observer_list *next;
-  struct observer *observer;
-};
 
-/* Allocate a struct observer_list, intended to be used as a node
-   in the list of observers maintained by a subject.  */
+/* This observer is used for internal testing.  */
+observable<int> test_notification ("test_notification");
 
-static struct observer_list *
-xalloc_observer_list_node (void)
-{
-  struct observer_list *node = XNEW (struct observer_list);
+static int test_first_observer = 0;
+static int test_second_observer = 0;
+static int test_third_observer = 0;
 
-  node->observer = XNEW (struct observer);
-  return node;
+static void
+test_first_notification_function (int arg)
+{
+  test_first_observer++;
 }
 
-/* The opposite of xalloc_observer_list_node, frees the memory for
-   the given node.  */
-
 static void
-xfree_observer_list_node (struct observer_list *node)
+test_second_notification_function (int arg)
 {
-  xfree (node->observer);
-  xfree (node);
+  test_second_observer++;
 }
 
-/* Attach the callback NOTIFY to a SUBJECT.  The DATA is also stored,
-   in order for the subject to provide it back to the observer during
-   a notification.  */
-
-static struct observer *
-generic_observer_attach (struct observer_list **subject,
-			 generic_observer_notification_ftype * notify,
-			 void *data)
+static void
+test_third_notification_function (int arg)
 {
-  struct observer_list *observer_list = xalloc_observer_list_node ();
-
-  observer_list->next = *subject;
-  observer_list->observer->notify = notify;
-  observer_list->observer->data = data;
-  *subject = observer_list;
-
-  return observer_list->observer;
+  test_third_observer++;
 }
 
-/* Remove the given OBSERVER from the SUBJECT.  Once detached, OBSERVER
-   should no longer be used, as it is no longer valid.  */
-
 static void
-generic_observer_detach (struct observer_list **subject,
-			 const struct observer *observer)
+notify_check_counters (int one, int two, int three)
 {
-  struct observer_list *previous_node = NULL;
-  struct observer_list *current_node = *subject;
-
-  while (current_node != NULL)
-    {
-      if (current_node->observer == observer)
-	{
-	  if (previous_node != NULL)
-	    previous_node->next = current_node->next;
-	  else
-	    *subject = current_node->next;
-	  xfree_observer_list_node (current_node);
-	  return;
-	}
-      previous_node = current_node;
-      current_node = current_node->next;
-    }
-
-  /* We should never reach this point.  However, this should not be
-     a very serious error, so simply report a warning to the user.  */
-  warning (_("Failed to detach observer"));
+  /* Reset.  */
+  test_first_observer = 0;
+  test_second_observer = 0;
+  test_third_observer = 0;
+  /* Notify.  */
+  test_notification.notify (0);
+  /* Check.  */
+  SELF_CHECK (one == test_first_observer);
+  SELF_CHECK (two == test_second_observer);
+  SELF_CHECK (three == test_third_observer);
 }
 
-/* Send a notification to all the observers of SUBJECT.  ARGS is passed to
-   all observers as an argument to the notification callback.  */
-
 static void
-generic_observer_notify (struct observer_list *subject, const void *args)
+observer_self_tests ()
 {
-  struct observer_list *current_node = subject;
-
-  while (current_node != NULL)
-    {
-      (*current_node->observer->notify) (current_node->observer->data, args);
-      current_node = current_node->next;
-    }
+  /* First, try sending a notification without any observer
+     attached.  */
+  notify_check_counters (0, 0, 0);
+
+  observable<int>::token_type token1, token2, token3;
+
+  /* Now, attach one observer, and send a notification.  */
+  token2 = test_notification.attach (&test_second_notification_function);
+  notify_check_counters (0, 1, 0);
+
+  /* Remove the observer, and send a notification.  */
+  test_notification.detach (token2);
+  notify_check_counters (0, 0, 0);
+
+  /* With a new observer.  */
+  token1 = test_notification.attach (&test_first_notification_function);
+  notify_check_counters (1, 0, 0);
+
+  /* With 2 observers.  */
+  token2 = test_notification.attach (&test_second_notification_function);
+  notify_check_counters (1, 1, 0);
+
+  /* With 3 observers.  */
+  token3 = test_notification.attach (&test_third_notification_function);
+  notify_check_counters (1, 1, 1);
+
+  /* Remove middle observer.  */
+  test_notification.detach (token2);
+  notify_check_counters (1, 0, 1);
+
+  /* Remove first observer.  */
+  test_notification.detach (token1);
+  notify_check_counters (0, 0, 1);
+
+  /* Remove last observer.  */
+  test_notification.detach (token3);
+  notify_check_counters (0, 0, 0);
+
+  /* Go back to 3 observers, and remove them in a different
+     order...  */
+  token1 = test_notification.attach (&test_first_notification_function);
+  token2 = test_notification.attach (&test_second_notification_function);
+  token3 = test_notification.attach (&test_third_notification_function);
+  notify_check_counters (1, 1, 1);
+
+  /* Remove the third observer.  */
+  test_notification.detach (token3);
+  notify_check_counters (1, 1, 0);
+
+  /* Remove the second observer.  */
+  test_notification.detach (token2);
+  notify_check_counters (1, 0, 0);
+
+  /* Remove first observer, no more observers.  */
+  test_notification.detach (token1);
+  notify_check_counters (0, 0, 0);
 }
 
+} /* namespace selftests */
 
-/* The following code is only used to unit-test the observers from our
-   testsuite.  DO NOT USE IT within observer.c (or anywhere else for
-   that matter)!  */
+#endif
 
-/* If we define these variables and functions as `static', the
-   compiler will optimize them out.  */
- 
-int observer_test_first_observer = 0;
-int observer_test_second_observer = 0;
-int observer_test_third_observer = 0;
+} /* namespace observers */
+} /* namespace gdb */
 
-void
-observer_test_first_notification_function (int arg)
-{
-  observer_test_first_observer++;
-}
-
-void
-observer_test_second_notification_function (int arg)
-{
-  observer_test_second_observer++;
-}
-
-void
-observer_test_third_notification_function (int arg)
+static void
+show_observer_debug (struct ui_file *file, int from_tty,
+		     struct cmd_list_element *c, const char *value)
 {
-  observer_test_third_observer++;
+  fprintf_filtered (file, _("Observer debugging is %s.\n"), value);
 }
 
 void
 _initialize_observer (void)
 {
   add_setshow_zuinteger_cmd ("observer", class_maintenance,
-			     &observer_debug, _("\
+			     &gdb::observers::observer_debug, _("\
 Set observer debugging."), _("\
 Show observer debugging."), _("\
 When non-zero, observer debugging is enabled."),
 			     NULL,
 			     show_observer_debug,
 			     &setdebuglist, &showdebuglist);
-}
 
-#include "observer.inc"
+#if GDB_SELF_TEST
+  selftests::register_test ("gdb::observers",
+			    gdb::observers::selftests::observer_self_tests);
+#endif
+}
diff --git a/gdb/observer.h b/gdb/observer.h
new file mode 100644
index 0000000000..34447b90bb
--- /dev/null
+++ b/gdb/observer.h
@@ -0,0 +1,235 @@ 
+/* Observers
+
+   Copyright (C) 2016-2018 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#if !defined (GDB_OBSERVER_H)
+#define GDB_OBSERVER_H
+
+#include "common/observable.h"
+
+struct bpstats;
+struct so_list;
+struct objfile;
+struct thread_info;
+struct inferior;
+struct trace_state_variable;
+
+namespace gdb
+{
+
+namespace observers
+{
+
+/* The inferior has stopped for real.  The bs argument describes the
+   breakpoints were are stopped at, if any.  Second argument
+   print_frame non-zero means display the location where the
+   inferior has stopped.
+
+   gdb notifies all normal_stop observers when the inferior execution
+   has just stopped, the associated messages and annotations have been
+   printed, and the control is about to be returned to the user.
+
+   Note that the normal_stop notification is not emitted when the
+   execution stops due to a breakpoint, and this breakpoint has a
+   condition that is not met.  If the breakpoint has any associated
+   commands list, the commands are executed after the notification is
+   emitted.  */
+extern observable<struct bpstats *, int> normal_stop;
+
+/* The inferior was stopped by a signal.  */
+extern observable<enum gdb_signal> signal_received;
+
+/* We are done with a step/next/si/ni command.  */
+extern observable<> end_stepping_range;
+
+/* The inferior was terminated by a signal.  */
+extern observable<enum gdb_signal> signal_exited;
+
+/* The inferior program is finished.  */
+extern observable<int> exited;
+
+/* Reverse execution: target ran out of history info.  */
+extern observable<> no_history;
+
+/* A synchronous command finished.  */
+extern observable<> sync_execution_done;
+
+/* An error was caught while executing a command.  */
+extern observable<> command_error;
+
+/* The target's register contents have changed.  */
+extern observable<struct target_ops *> target_changed;
+
+/* The executable being debugged by GDB has changed: The user
+   decided to debug a different program, or the program he was
+   debugging has been modified since being loaded by the debugger
+   (by being recompiled, for instance).  */
+extern observable<> executable_changed;
+
+/* gdb has just connected to an inferior.  For 'run', gdb calls this
+   observer while the inferior is still stopped at the entry-point
+   instruction.  For 'attach' and 'core', gdb calls this observer
+   immediately after connecting to the inferior, and before any
+   information on the inferior has been printed.  */
+extern observable<struct target_ops *, int> inferior_created;
+
+/* The status of process record for inferior inferior in gdb has
+   changed.  The process record is started if started is true, and
+   the process record is stopped if started is false.
+
+   When started is true, method indicates the short name of the
+   method used for recording.  If the method supports multiple
+   formats, format indicates which one is being used, otherwise it
+   is NULL.  When started is false, they are both NULL.  */
+extern observable<struct inferior *, int, const char *, const char *>
+    record_changed;
+
+/* The shared library specified by solib has been loaded.  Note that
+   when gdb calls this observer, the library's symbols probably
+   haven't been loaded yet.  */
+extern observable<struct so_list *> solib_loaded;
+
+/* The shared library specified by solib has been unloaded.  Note
+   that when gdb calls this observer, the library's symbols have not
+   been unloaded yet, and thus are still available.  */
+extern observable<struct so_list *> solib_unloaded;
+
+/* The symbol file specified by objfile has been loaded.  Called
+   with objfile equal to NULL to indicate previously loaded symbol
+   table data has now been invalidated.  */
+extern observable<struct objfile *> new_objfile;
+
+/* The object file specified by objfile is about to be freed.  */
+extern observable<struct objfile *> free_objfile;
+
+/* The thread specified by t has been created.  */
+extern observable<struct thread_info *> new_thread;
+
+/* The thread specified by t has exited.  The silent argument
+   indicates that gdb is removing the thread from its tables without
+   wanting to notify the user about it.  */
+extern observable<struct thread_info *, int> thread_exit;
+
+/* An explicit stop request was issued to ptid.  If ptid equals
+   minus_one_ptid, the request applied to all threads.  If
+   ptid_is_pid(ptid) returns true, the request applied to all
+   threads of the process pointed at by ptid.  Otherwise, the
+   request applied to the single thread pointed at by ptid.  */
+extern observable<ptid_t> thread_stop_requested;
+
+/* The target was resumed.  The ptid parameter specifies which
+   thread was resume, and may be RESUME_ALL if all threads are
+   resumed.  */
+extern observable<ptid_t> target_resumed;
+
+/* The target is about to be proceeded.  */
+extern observable<> about_to_proceed;
+
+/* A new breakpoint b has been created.  */
+extern observable<struct breakpoint *> breakpoint_created;
+
+/* A breakpoint has been destroyed.  The argument b is the
+   pointer to the destroyed breakpoint.  */
+extern observable<struct breakpoint *> breakpoint_deleted;
+
+/* A breakpoint has been modified in some way.  The argument b
+   is the modified breakpoint.  */
+extern observable<struct breakpoint *> breakpoint_modified;
+
+/* The trace frame is changed to tfnum (e.g., by using the 'tfind'
+   command).  If tfnum is negative, it means gdb resumes live
+   debugging.  The number of the tracepoint associated with this
+   traceframe is tpnum.  */
+extern observable<int, int> traceframe_changed;
+
+/* The current architecture has changed.  The argument newarch is a
+   pointer to the new architecture.  */
+extern observable<struct gdbarch *> architecture_changed;
+
+/* The thread's ptid has changed.  The old_ptid parameter specifies
+   the old value, and new_ptid specifies the new value.  */
+extern observable<ptid_t, ptid_t> thread_ptid_changed;
+
+/* The inferior inf has been added to the list of inferiors.  At
+   this point, it might not be associated with any process.  */
+extern observable<struct inferior *> inferior_added;
+
+/* The inferior identified by inf has been attached to a
+   process.  */
+extern observable<struct inferior *> inferior_appeared;
+
+/* Either the inferior associated with inf has been detached from
+   the process, or the process has exited.  */
+extern observable<struct inferior *> inferior_exit;
+
+/* The inferior inf has been removed from the list of inferiors.
+   This method is called immediately before freeing inf.  */
+extern observable<struct inferior *> inferior_removed;
+
+/* Bytes from data to data + len have been written to the inferior
+   at addr.  */
+extern observable<struct inferior *, CORE_ADDR, ssize_t, const bfd_byte *>
+    memory_changed;
+
+/* Called before a top-level prompt is displayed.  current_prompt is
+   the current top-level prompt.  */
+extern observable<const char *> before_prompt;
+
+/* Variable gdb_datadir has been set.  The value may not necessarily
+   change.  */
+extern observable<> gdb_datadir_changed;
+
+/* The parameter of some 'set' commands in console are changed.
+   This method is called after a command 'set param value'.  param
+   is the parameter of 'set' command, and value is the value of
+   changed parameter.  */
+extern observable<const char *, const char *> command_param_changed;
+
+/* The new trace state variable tsv is created.  */
+extern observable<const struct trace_state_variable *> tsv_created;
+
+/* The trace state variable tsv is deleted.  If tsv is NULL, all
+   trace state variables are deleted.  */
+extern observable<const struct trace_state_variable *> tsv_deleted;
+
+/* The trace state value tsv is modified.  */
+extern observable<const struct trace_state_variable *> tsv_modified;
+
+/* An inferior function at address is about to be called in thread
+   thread.  */
+extern observable<ptid_t, CORE_ADDR> inferior_call_pre;
+
+/* The inferior function at address has just been called.  This
+   observer is called even if the inferior exits during the call.
+   thread is the thread in which the function was called, which may
+   be different from the current thread.  */
+extern observable<ptid_t, CORE_ADDR> inferior_call_post;
+
+/* A register in the inferior has been modified by the gdb user.  */
+extern observable<struct frame_info *, int> register_changed;
+
+/* The user-selected inferior, thread and/or frame has changed.  The
+   user_select_what flag specifies if the inferior, thread and/or
+   frame has changed.  */
+extern observable<user_selected_what> user_selected_context_changed;
+
+} /* namespace observers */
+
+} /* namespace gdb */
+
+#endif /* GDB_OBSERVER_H */
diff --git a/gdb/observer.sh b/gdb/observer.sh
deleted file mode 100755
index fa3dcc505f..0000000000
--- a/gdb/observer.sh
+++ /dev/null
@@ -1,200 +0,0 @@ 
-#!/bin/sh -e
-
-# Make certain that the script is not running in an internationalized
-# environment.
-LANG=C ; export LANG
-LC_ALL=C ; export LC_ALL
-
-if test $# -ne 3
-then
-    echo "Usage: $0 <h|inc> <observer.texi> <observer.out>" 1>&2
-    exit 0
-fi
-
-lang=$1 ; shift
-texi=$1 ; shift
-o=$1
-case $lang in
-  h) tmp=htmp ;;
-  inc) tmp=itmp ;;
-esac
-otmp="`echo $1 | sed -e 's,\.[^.]*$,,'`.$tmp"; shift
-echo "Creating ${otmp}" 1>&2
-rm -f ${otmp}
-
-# Can use any of the following: cat cmp cp diff echo egrep expr false
-# grep install-info ln ls mkdir mv pwd rm rmdir sed sleep sort tar
-# test touch true
-
-cat <<EOF >>${otmp}
-/* GDB Notifications to Observers.
-
-   Copyright (C) 2004-2018 Free Software Foundation, Inc.
-
-   This file is part of GDB.
-
-   This program is free software; you can redistribute it and/or modify
-   it under the terms of the GNU General Public License as published by
-   the Free Software Foundation; either version 3 of the License, or
-   (at your option) any later version.
-  
-   This program is distributed in the hope that it will be useful,
-   but WITHOUT ANY WARRANTY; without even the implied warranty of
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-   GNU General Public License for more details.
-  
-   You should have received a copy of the GNU General Public License
-   along with this program.  If not, see <http://www.gnu.org/licenses/>.
-
-   --
-
-   This file was generated using observer.sh and observer.texi.  */
-
-EOF
-
-
-case $lang in
-    h) cat <<EOF >>${otmp}
-#ifndef OBSERVER_H
-#define OBSERVER_H
-
-struct observer;
-struct bpstats;
-struct so_list;
-struct objfile;
-struct thread_info;
-struct inferior;
-struct trace_state_variable;
-EOF
-        ;;
-esac
-
-# We are about to set IFS=:, so DOS-style file names with a drive
-# letter and a colon will be in trouble.
-
-if test -n "$DJGPP"
-then
-     texi=`echo $texi | sed -e 's,^\([a-zA-Z]\):/,/dev/\1/,'`
-fi
-
-# generate a list of events that can be observed
-
-IFS=:
-sed -n '
-/@deftypefun void/{
-# Save original line for later processing into the actual parameter
-    h
-# Convert from: @deftypefun void EVENT (TYPE @var{PARAM},...)
-# to event and formals: EVENT:TYPE PARAM, ...:
-    s/^.* void \([a-z_][a-z_]*\) (\(.*\))$/\1:\2/
-    s/@var{//g
-    s/}//g
-# Switch to held
-    x
-# Convert from: @deftypefun void FUNC (TYPE @var{PARAM},...)
-# to actuals: PARAM, ...
-    s/^[^{]*[{]*//
-    s/[}]*[^}]*$//
-    s/}[^{]*{/, /g
-# Combine held (EVENT:TYPE PARAM, ...:) and pattern (PARAM, ...) into
-# FUNC:TYPE PARAM, ...:PARAM, ...
-    H
-    x
-    s/\n/:/g
-    p
-}
-' $texi | while read event formal actual
-do
-  case $lang in
-      h) cat <<EOF >>${otmp}
-
-/* ${event} notifications.  */
-
-typedef void (observer_${event}_ftype) (${formal});
-
-extern struct observer *observer_attach_${event} (observer_${event}_ftype *f);
-extern void observer_detach_${event} (struct observer *observer);
-extern void observer_notify_${event} (${formal});
-EOF
-	;;
-
-      inc)
-      	cat <<EOF >>${otmp}
-
-/* ${event} notifications.  */
-
-static struct observer_list *${event}_subject = NULL;
-
-EOF
-	if test "$formal" != "void"; then
-	    cat<<EOF >>${otmp}
-struct ${event}_args { `echo "${formal}" | sed -e 's/,/;/g'`; };
-
-EOF
-	fi
-	cat <<EOF >>${otmp}
-static void
-observer_${event}_notification_stub (const void *data, const void *args_data)
-{
-  observer_${event}_ftype *notify = (observer_${event}_ftype *) data;
-EOF
-
-	notify_args=`echo ${actual} | sed -e 's/\([a-z0-9_][a-z0-9_]*\)/args->\1/g'`
-
-	if test ! -z "${notify_args}"; then
-	    cat<<EOF >>${otmp}
-  const struct ${event}_args *args = (const struct ${event}_args *) args_data;
-EOF
-	fi
-	cat <<EOF >>${otmp}
-  notify (${notify_args});
-}
-
-struct observer *
-observer_attach_${event} (observer_${event}_ftype *f)
-{
-  return generic_observer_attach (&${event}_subject,
-				  &observer_${event}_notification_stub,
-				  (void *) f);
-}
-
-void
-observer_detach_${event} (struct observer *observer)
-{
-  generic_observer_detach (&${event}_subject, observer);
-}
-
-void
-observer_notify_${event} (${formal})
-{
-EOF
-	if test "$formal" != "void"; then
-	    cat<<EOF >>${otmp}
-  struct ${event}_args args;
-  `echo ${actual} | sed -e 's/\([a-z0-9_][a-z0-9_]*\)/args.\1 = \1/g'`;
-
-EOF
-	else
-	    echo "char *args = NULL;" >> ${otmp}
-	fi
-	cat<<EOF >>${otmp}
-  if (observer_debug)
-    fprintf_unfiltered (gdb_stdlog, "observer_notify_${event}() called\n");
-  generic_observer_notify (${event}_subject, &args);
-}
-EOF
-	;;
-    esac
-done
-
-
-case $lang in
-    h) cat <<EOF >>${otmp}
-
-#endif /* OBSERVER_H */
-EOF
-esac
-
-
-echo Moving ${otmp} to ${o}
-mv ${otmp} ${o}
diff --git a/gdb/ppc-linux-nat.c b/gdb/ppc-linux-nat.c
index 8418e4d35d..679cd4db96 100644
--- a/gdb/ppc-linux-nat.c
+++ b/gdb/ppc-linux-nat.c
@@ -2500,7 +2500,7 @@  _initialize_ppc_linux_nat (void)
   t->to_read_description = ppc_linux_read_description;
   t->to_auxv_parse = ppc_linux_auxv_parse;
 
-  observer_attach_thread_exit (ppc_linux_thread_exit);
+  gdb::observers::thread_exit.attach (ppc_linux_thread_exit);
 
   /* Register the target.  */
   linux_nat_add_target (t);
diff --git a/gdb/ppc-linux-tdep.c b/gdb/ppc-linux-tdep.c
index ed0ea13461..30106d586d 100644
--- a/gdb/ppc-linux-tdep.c
+++ b/gdb/ppc-linux-tdep.c
@@ -1857,9 +1857,9 @@  _initialize_ppc_linux_tdep (void)
                          ppc_linux_init_abi);
 
   /* Attach to observers to track __spe_current_active_context.  */
-  observer_attach_inferior_created (ppc_linux_spe_context_inferior_created);
-  observer_attach_solib_loaded (ppc_linux_spe_context_solib_loaded);
-  observer_attach_solib_unloaded (ppc_linux_spe_context_solib_unloaded);
+  gdb::observers::inferior_created.attach (ppc_linux_spe_context_inferior_created);
+  gdb::observers::solib_loaded.attach (ppc_linux_spe_context_solib_loaded);
+  gdb::observers::solib_unloaded.attach (ppc_linux_spe_context_solib_unloaded);
 
   /* Initialize the Linux target descriptions.  */
   initialize_tdesc_powerpc_32l ();
diff --git a/gdb/printcmd.c b/gdb/printcmd.c
index fc9d7e4dd9..fad0fbbb90 100644
--- a/gdb/printcmd.c
+++ b/gdb/printcmd.c
@@ -2612,7 +2612,7 @@  _initialize_printcmd (void)
 
   current_display_number = -1;
 
-  observer_attach_free_objfile (clear_dangling_display_expressions);
+  gdb::observers::free_objfile.attach (clear_dangling_display_expressions);
 
   add_info ("address", info_address_command,
 	    _("Describe where symbol SYM is stored."));
diff --git a/gdb/procfs.c b/gdb/procfs.c
index 374faa92e2..b3629364a2 100644
--- a/gdb/procfs.c
+++ b/gdb/procfs.c
@@ -3760,7 +3760,7 @@  proc_untrace_sysexit_cmd (const char *args, int from_tty)
 void
 _initialize_procfs (void)
 {
-  observer_attach_inferior_created (procfs_inferior_created);
+  gdb::observers::inferior_created.attach (procfs_inferior_created);
 
   add_com ("proc-trace-entry", no_class, proc_trace_sysentry_cmd,
 	   _("Give a trace of entries into the syscall."));
diff --git a/gdb/python/py-breakpoint.c b/gdb/python/py-breakpoint.c
index 5ac3f98641..132eccac34 100644
--- a/gdb/python/py-breakpoint.c
+++ b/gdb/python/py-breakpoint.c
@@ -1086,9 +1086,9 @@  gdbpy_initialize_breakpoints (void)
 			      (PyObject *) &breakpoint_object_type) < 0)
     return -1;
 
-  observer_attach_breakpoint_created (gdbpy_breakpoint_created);
-  observer_attach_breakpoint_deleted (gdbpy_breakpoint_deleted);
-  observer_attach_breakpoint_modified (gdbpy_breakpoint_modified);
+  gdb::observers::breakpoint_created.attach (gdbpy_breakpoint_created);
+  gdb::observers::breakpoint_deleted.attach (gdbpy_breakpoint_deleted);
+  gdb::observers::breakpoint_modified.attach (gdbpy_breakpoint_modified);
 
   /* Add breakpoint types constants.  */
   for (i = 0; pybp_codes[i].name; ++i)
diff --git a/gdb/python/py-finishbreakpoint.c b/gdb/python/py-finishbreakpoint.c
index 7a05ad3195..b95231a6b5 100644
--- a/gdb/python/py-finishbreakpoint.c
+++ b/gdb/python/py-finishbreakpoint.c
@@ -416,8 +416,8 @@  gdbpy_initialize_finishbreakpoints (void)
 			      (PyObject *) &finish_breakpoint_object_type) < 0)
     return -1;
 
-  observer_attach_normal_stop (bpfinishpy_handle_stop);
-  observer_attach_inferior_exit (bpfinishpy_handle_exit);
+  gdb::observers::normal_stop.attach (bpfinishpy_handle_stop);
+  gdb::observers::inferior_exit.attach (bpfinishpy_handle_exit);
 
   return 0;
 }
diff --git a/gdb/python/py-inferior.c b/gdb/python/py-inferior.c
index 564aa79f17..1ac8caa335 100644
--- a/gdb/python/py-inferior.c
+++ b/gdb/python/py-inferior.c
@@ -926,18 +926,18 @@  gdbpy_initialize_inferior (void)
   infpy_inf_data_key =
     register_inferior_data_with_cleanup (NULL, py_free_inferior);
 
-  observer_attach_new_thread (add_thread_object);
-  observer_attach_thread_exit (delete_thread_object);
-  observer_attach_normal_stop (python_on_normal_stop);
-  observer_attach_target_resumed (python_on_resume);
-  observer_attach_inferior_call_pre (python_on_inferior_call_pre);
-  observer_attach_inferior_call_post (python_on_inferior_call_post);
-  observer_attach_memory_changed (python_on_memory_change);
-  observer_attach_register_changed (python_on_register_change);
-  observer_attach_inferior_exit (python_inferior_exit);
-  observer_attach_new_objfile (python_new_objfile);
-  observer_attach_inferior_added (python_new_inferior);
-  observer_attach_inferior_removed (python_inferior_deleted);
+  gdb::observers::new_thread.attach (add_thread_object);
+  gdb::observers::thread_exit.attach (delete_thread_object);
+  gdb::observers::normal_stop.attach (python_on_normal_stop);
+  gdb::observers::target_resumed.attach (python_on_resume);
+  gdb::observers::inferior_call_pre.attach (python_on_inferior_call_pre);
+  gdb::observers::inferior_call_post.attach (python_on_inferior_call_post);
+  gdb::observers::memory_changed.attach (python_on_memory_change);
+  gdb::observers::register_changed.attach (python_on_register_change);
+  gdb::observers::inferior_exit.attach (python_inferior_exit);
+  gdb::observers::new_objfile.attach (python_new_objfile);
+  gdb::observers::inferior_added.attach (python_new_inferior);
+  gdb::observers::inferior_removed.attach (python_inferior_deleted);
 
   membuf_object_type.tp_new = PyType_GenericNew;
   if (PyType_Ready (&membuf_object_type) < 0)
diff --git a/gdb/python/py-unwind.c b/gdb/python/py-unwind.c
index a7e3a93ebc..e6b40256d4 100644
--- a/gdb/python/py-unwind.c
+++ b/gdb/python/py-unwind.c
@@ -663,7 +663,7 @@  gdbpy_initialize_unwind (void)
         &setdebuglist, &showdebuglist);
   pyuw_gdbarch_data
       = gdbarch_data_register_post_init (pyuw_gdbarch_data_init);
-  observer_attach_architecture_changed (pyuw_on_new_gdbarch);
+  gdb::observers::architecture_changed.attach (pyuw_on_new_gdbarch);
 
   if (PyType_Ready (&pending_frame_object_type) < 0)
     return -1;
diff --git a/gdb/ravenscar-thread.c b/gdb/ravenscar-thread.c
index 19bdd7dc8d..aab6fc90d6 100644
--- a/gdb/ravenscar-thread.c
+++ b/gdb/ravenscar-thread.c
@@ -632,7 +632,7 @@  _initialize_ravenscar (void)
 
   /* Notice when the inferior is created in order to push the
      ravenscar ops if needed.  */
-  observer_attach_inferior_created (ravenscar_inferior_created);
+  gdb::observers::inferior_created.attach (ravenscar_inferior_created);
 
   complete_target_initialization (&ravenscar_ops);
 
diff --git a/gdb/record-btrace.c b/gdb/record-btrace.c
index 2464672473..c0f36268ea 100644
--- a/gdb/record-btrace.c
+++ b/gdb/record-btrace.c
@@ -45,7 +45,8 @@ 
 static struct target_ops record_btrace_ops;
 
 /* A new thread observer enabling branch tracing for the new thread.  */
-static struct observer *record_btrace_thread_observer;
+static gdb::observers::observable<struct thread_info *>::token_type
+  record_btrace_thread_observer;
 
 /* Memory access types used in set/show record btrace replay-memory-access.  */
 static const char replay_memory_access_read_only[] = "read-only";
@@ -177,7 +178,7 @@  record_btrace_auto_enable (void)
   DEBUG ("attach thread observer");
 
   record_btrace_thread_observer
-    = observer_attach_new_thread (record_btrace_enable_warn);
+    = gdb::observers::new_thread.attach (record_btrace_enable_warn);
 }
 
 /* Disable automatic tracing of new threads.  */
@@ -186,13 +187,13 @@  static void
 record_btrace_auto_disable (void)
 {
   /* The observer may have been detached, already.  */
-  if (record_btrace_thread_observer == NULL)
+  if (record_btrace_thread_observer == gdb::observers::new_thread.null_token)
     return;
 
   DEBUG ("detach thread observer");
 
-  observer_detach_new_thread (record_btrace_thread_observer);
-  record_btrace_thread_observer = NULL;
+  gdb::observers::new_thread.detach (record_btrace_thread_observer);
+  record_btrace_thread_observer = gdb::observers::new_thread.null_token;
 }
 
 /* The record-btrace async event handler function.  */
@@ -220,7 +221,7 @@  record_btrace_push_target (void)
   record_btrace_generating_corefile = 0;
 
   format = btrace_format_short_string (record_btrace_conf.format);
-  observer_notify_record_changed (current_inferior (), 1, "btrace", format);
+  gdb::observers::record_changed.notify (current_inferior (), 1, "btrace", format);
 }
 
 /* The to_open method of target record-btrace.  */
@@ -238,7 +239,8 @@  record_btrace_open (const char *args, int from_tty)
   if (!target_has_execution)
     error (_("The program is not being run."));
 
-  gdb_assert (record_btrace_thread_observer == NULL);
+  gdb_assert (record_btrace_thread_observer
+	      == gdb::observers::new_thread.null_token);
 
   disable_chain = make_cleanup (null_cleanup, NULL);
   ALL_NON_EXITED_THREADS (tp)
@@ -3137,4 +3139,6 @@  to see the actual buffer size."), NULL, show_record_pt_buffer_size_value,
 
   record_btrace_conf.bts.size = 64 * 1024;
   record_btrace_conf.pt.size = 16 * 1024;
+
+  record_btrace_thread_observer = gdb::observers::new_thread.null_token;
 }
diff --git a/gdb/record-full.c b/gdb/record-full.c
index 13a973877e..6dc2c10dc1 100644
--- a/gdb/record-full.c
+++ b/gdb/record-full.c
@@ -851,7 +851,7 @@  record_full_open (const char *name, int from_tty)
 
   record_full_init_record_breakpoints ();
 
-  observer_notify_record_changed (current_inferior (),  1, "full", NULL);
+  gdb::observers::record_changed.notify (current_inferior (),  1, "full", NULL);
 }
 
 /* "to_close" target method.  Close the process record target.  */
diff --git a/gdb/record.c b/gdb/record.c
index 9a476142e9..8375832753 100644
--- a/gdb/record.c
+++ b/gdb/record.c
@@ -311,7 +311,7 @@  cmd_record_stop (const char *args, int from_tty)
   printf_unfiltered (_("Process record is stopped and all execution "
 		       "logs are deleted.\n"));
 
-  observer_notify_record_changed (current_inferior (), 0, NULL, NULL);
+  gdb::observers::record_changed.notify (current_inferior (), 0, NULL, NULL);
 }
 
 /* The "set record" command.  */
diff --git a/gdb/regcache.c b/gdb/regcache.c
index ab750c6170..4becc8efcf 100644
--- a/gdb/regcache.c
+++ b/gdb/regcache.c
@@ -2057,8 +2057,9 @@  _initialize_regcache (void)
   regcache_descr_handle
     = gdbarch_data_register_post_init (init_regcache_descr);
 
-  observer_attach_target_changed (regcache_observer_target_changed);
-  observer_attach_thread_ptid_changed (regcache::regcache_thread_ptid_changed);
+  gdb::observers::target_changed.attach (regcache_observer_target_changed);
+  gdb::observers::thread_ptid_changed.attach
+    (regcache::regcache_thread_ptid_changed);
 
   add_com ("flushregs", class_maintenance, reg_flush_command,
 	   _("Force gdb to flush its register cache (maintainer command)"));
diff --git a/gdb/remote.c b/gdb/remote.c
index b320ee07c9..ebd428f72d 100644
--- a/gdb/remote.c
+++ b/gdb/remote.c
@@ -3824,9 +3824,9 @@  print_one_stopped_thread (struct thread_info *thread)
       enum gdb_signal sig = ws->value.sig;
 
       if (signal_print_state (sig))
-	observer_notify_signal_received (sig);
+	gdb::observers::signal_received.notify (sig);
     }
-  observer_notify_normal_stop (NULL, 1);
+  gdb::observers::normal_stop.notify (NULL, 1);
 }
 
 /* Process all initial stop replies the remote side sent in response
@@ -13963,10 +13963,10 @@  _initialize_remote (void)
   add_target (&extended_remote_ops);
 
   /* Hook into new objfile notification.  */
-  observer_attach_new_objfile (remote_new_objfile);
+  gdb::observers::new_objfile.attach (remote_new_objfile);
   /* We're no longer interested in notification events of an inferior
      when it exits.  */
-  observer_attach_inferior_exit (discard_pending_stop_replies);
+  gdb::observers::inferior_exit.attach (discard_pending_stop_replies);
 
 #if 0
   init_remote_threadtests ();
diff --git a/gdb/sol-thread.c b/gdb/sol-thread.c
index 2c7dd0e15d..67767d901a 100644
--- a/gdb/sol-thread.c
+++ b/gdb/sol-thread.c
@@ -1229,7 +1229,7 @@  _initialize_sol_thread (void)
 	   _("Show info on Solaris user threads."), &maintenanceinfolist);
 
   /* Hook into new_objfile notification.  */
-  observer_attach_new_objfile (sol_thread_new_objfile);
+  gdb::observers::new_objfile.attach (sol_thread_new_objfile);
   return;
 
  die:
diff --git a/gdb/solib-aix.c b/gdb/solib-aix.c
index 463f060845..7081163eff 100644
--- a/gdb/solib-aix.c
+++ b/gdb/solib-aix.c
@@ -790,7 +790,7 @@  _initialize_solib_aix (void)
 
   solib_aix_inferior_data_handle = register_inferior_data ();
 
-  observer_attach_normal_stop (solib_aix_normal_stop_observer);
+  gdb::observers::normal_stop.attach (solib_aix_normal_stop_observer);
 
   /* Debug this file's internals.  */
   add_setshow_boolean_cmd ("aix-solib", class_maintenance,
diff --git a/gdb/solib-spu.c b/gdb/solib-spu.c
index d0d63b5ef5..b464aeebfe 100644
--- a/gdb/solib-spu.c
+++ b/gdb/solib-spu.c
@@ -545,7 +545,7 @@  spu_solib_loaded (struct so_list *so)
 void
 _initialize_spu_solib (void)
 {
-  observer_attach_solib_loaded (spu_solib_loaded);
+  gdb::observers::solib_loaded.attach (spu_solib_loaded);
   ocl_program_data_key = register_objfile_data ();
 }
 
diff --git a/gdb/solib.c b/gdb/solib.c
index 40fdfc59e6..cdcb3df515 100644
--- a/gdb/solib.c
+++ b/gdb/solib.c
@@ -839,7 +839,7 @@  update_solib_list (int from_tty)
 	{
 	  /* Notify any observer that the shared object has been
 	     unloaded before we remove it from GDB's tables.  */
-	  observer_notify_solib_unloaded (gdb);
+	  gdb::observers::solib_unloaded.notify (gdb);
 
 	  VEC_safe_push (char_ptr, current_program_space->deleted_solibs,
 			 xstrdup (gdb->so_name));
@@ -901,7 +901,7 @@  update_solib_list (int from_tty)
 
 	  /* Notify any observer that the shared object has been
 	     loaded now that we've added it to GDB's tables.  */
-	  observer_notify_solib_loaded (i);
+	  gdb::observers::solib_loaded.notify (i);
 	}
 
       /* If a library was not found, issue an appropriate warning
@@ -1209,7 +1209,7 @@  clear_solib (void)
       struct so_list *so = so_list_head;
 
       so_list_head = so->next;
-      observer_notify_solib_unloaded (so);
+      gdb::observers::solib_unloaded.notify (so);
       remove_target_sections (so);
       free_so (so);
     }
@@ -1613,7 +1613,7 @@  _initialize_solib (void)
 {
   solib_data = gdbarch_data_register_pre_init (solib_init);
 
-  observer_attach_free_objfile (remove_user_added_objfile);
+  gdb::observers::free_objfile.attach (remove_user_added_objfile);
 
   add_com ("sharedlibrary", class_files, sharedlibrary_command,
 	   _("Load shared object library symbols for files matching REGEXP."));
diff --git a/gdb/spu-multiarch.c b/gdb/spu-multiarch.c
index 7152ddabbd..35adcc8fcb 100644
--- a/gdb/spu-multiarch.c
+++ b/gdb/spu-multiarch.c
@@ -410,8 +410,8 @@  _initialize_spu_multiarch (void)
   complete_target_initialization (&spu_ops);
 
   /* Install observers to watch for SPU objects.  */
-  observer_attach_inferior_created (spu_multiarch_inferior_created);
-  observer_attach_solib_loaded (spu_multiarch_solib_loaded);
-  observer_attach_solib_unloaded (spu_multiarch_solib_unloaded);
+  gdb::observers::inferior_created.attach (spu_multiarch_inferior_created);
+  gdb::observers::solib_loaded.attach (spu_multiarch_solib_loaded);
+  gdb::observers::solib_unloaded.attach (spu_multiarch_solib_unloaded);
 }
 
diff --git a/gdb/spu-tdep.c b/gdb/spu-tdep.c
index f2f4f65647..167fd1872e 100644
--- a/gdb/spu-tdep.c
+++ b/gdb/spu-tdep.c
@@ -2770,14 +2770,14 @@  _initialize_spu_tdep (void)
   register_gdbarch_init (bfd_arch_spu, spu_gdbarch_init);
 
   /* Add ourselves to objfile event chain.  */
-  observer_attach_new_objfile (spu_overlay_new_objfile);
+  gdb::observers::new_objfile.attach (spu_overlay_new_objfile);
   spu_overlay_data = register_objfile_data ();
 
   /* Install spu stop-on-load handler.  */
-  observer_attach_new_objfile (spu_catch_start);
+  gdb::observers::new_objfile.attach (spu_catch_start);
 
   /* Add ourselves to normal_stop event chain.  */
-  observer_attach_normal_stop (spu_attach_normal_stop);
+  gdb::observers::normal_stop.attach (spu_attach_normal_stop);
 
   /* Add root prefix command for all "set spu"/"show spu" commands.  */
   add_prefix_cmd ("spu", no_class, set_spu_command,
diff --git a/gdb/stack.c b/gdb/stack.c
index 9993ae654a..64a817ceda 100644
--- a/gdb/stack.c
+++ b/gdb/stack.c
@@ -2273,7 +2273,7 @@  select_frame_command (const char *level_exp, int from_tty)
 
   select_frame (parse_frame_specification (level_exp, NULL));
   if (get_selected_frame_if_set () != prev_frame)
-    observer_notify_user_selected_context_changed (USER_SELECTED_FRAME);
+    gdb::observers::user_selected_context_changed.notify (USER_SELECTED_FRAME);
 }
 
 /* The "frame" command.  With no argument, print the selected frame
@@ -2287,7 +2287,7 @@  frame_command (const char *level_exp, int from_tty)
 
   select_frame (parse_frame_specification (level_exp, NULL));
   if (get_selected_frame_if_set () != prev_frame)
-    observer_notify_user_selected_context_changed (USER_SELECTED_FRAME);
+    gdb::observers::user_selected_context_changed.notify (USER_SELECTED_FRAME);
   else
     print_selected_thread_frame (current_uiout, USER_SELECTED_FRAME);
 }
@@ -2320,7 +2320,7 @@  static void
 up_command (const char *count_exp, int from_tty)
 {
   up_silently_base (count_exp);
-  observer_notify_user_selected_context_changed (USER_SELECTED_FRAME);
+  gdb::observers::user_selected_context_changed.notify (USER_SELECTED_FRAME);
 }
 
 /* Select the frame down one or COUNT_EXP stack levels from the previously
@@ -2359,7 +2359,7 @@  static void
 down_command (const char *count_exp, int from_tty)
 {
   down_silently_base (count_exp);
-  observer_notify_user_selected_context_changed (USER_SELECTED_FRAME);
+  gdb::observers::user_selected_context_changed.notify (USER_SELECTED_FRAME);
 }
 
 void
diff --git a/gdb/symfile-mem.c b/gdb/symfile-mem.c
index 8d91c729a5..d3f191889f 100644
--- a/gdb/symfile-mem.c
+++ b/gdb/symfile-mem.c
@@ -229,5 +229,5 @@  _initialize_symfile_mem (void)
 
   /* Want to know of each new inferior so that its vsyscall info can
      be extracted.  */
-  observer_attach_inferior_created (add_vsyscall_page);
+  gdb::observers::inferior_created.attach (add_vsyscall_page);
 }
diff --git a/gdb/symfile.c b/gdb/symfile.c
index ab6ec1cdad..d8c240820f 100644
--- a/gdb/symfile.c
+++ b/gdb/symfile.c
@@ -1211,13 +1211,13 @@  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);
@@ -2650,14 +2650,14 @@  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 ();
     }
 }
 
@@ -2894,7 +2894,7 @@  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
@@ -3900,7 +3900,7 @@  _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\
diff --git a/gdb/symtab.c b/gdb/symtab.c
index 0fd3f3a30f..294d576fec 100644
--- a/gdb/symtab.c
+++ b/gdb/symtab.c
@@ -5916,7 +5916,7 @@  If zero then the symbol cache is disabled."),
 	   _("Flush the symbol cache for each program space."),
 	   &maintenancelist);
 
-  observer_attach_executable_changed (symtab_observer_executable_changed);
-  observer_attach_new_objfile (symtab_new_objfile_observer);
-  observer_attach_free_objfile (symtab_free_objfile_observer);
+  gdb::observers::executable_changed.attach (symtab_observer_executable_changed);
+  gdb::observers::new_objfile.attach (symtab_new_objfile_observer);
+  gdb::observers::free_objfile.attach (symtab_free_objfile_observer);
 }
diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index 18512b9724..8dcec03c3d 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,7 @@ 
+2017-11-04  Tom Tromey  <tom@tromey.com>
+
+	* gdb.gdb/observer.exp: Remove.
+
 2018-02-07  Simon Marchi  <simon.marchi@ericsson.com>
 
 	* gdb.cp/m-static.exp: Check type of optimized out static
diff --git a/gdb/testsuite/gdb.gdb/observer.exp b/gdb/testsuite/gdb.gdb/observer.exp
deleted file mode 100644
index 1b514640d3..0000000000
--- a/gdb/testsuite/gdb.gdb/observer.exp
+++ /dev/null
@@ -1,143 +0,0 @@ 
-# Copyright 2003-2018 Free Software Foundation, Inc.
-
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation; either version 3 of the License, or
-# (at your option) any later version.
-#
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program.  If not, see <http://www.gnu.org/licenses/>.
-
-# This file was written by Joel Brobecker (brobecker@gnat.com), derived
-# from xfullpath.exp.
-
-load_lib selftest-support.exp
-
-proc attach_first_observer { message } {
-    gdb_test_no_output "set \$first_obs = observer_attach_test_notification (&observer_test_first_notification_function)" \
-	"$message; attach first observer"
-}
-
-proc attach_second_observer { message } {
-    gdb_test_no_output "set \$second_obs = observer_attach_test_notification (&observer_test_second_notification_function)" \
-	"$message; attach second observer"
-}
-
-proc attach_third_observer { message } {
-    gdb_test_no_output "set \$third_obs = observer_attach_test_notification (&observer_test_third_notification_function)" \
-	"$message; attach third observer"
-}
-
-proc detach_first_observer { message } {
-    gdb_test_no_output "call observer_detach_test_notification (\$first_obs)" \
-	"$message; detach first observer"
-}
-
-proc detach_second_observer { message } {
-    gdb_test_no_output "call observer_detach_test_notification (\$second_obs)" \
-	"$message; detach second observer"
-}
-
-proc detach_third_observer { message } {
-    gdb_test_no_output "call observer_detach_test_notification (\$third_obs)" \
-	"$message; detach third observer"
-}
-
-proc check_counters { first second third message } {
-    gdb_test "print observer_test_first_observer" \
-	".\[0-9\]+ =.*$first" \
-	"$message; check first observer counter value"
-    gdb_test "print observer_test_second_observer" \
-	".\[0-9\]+ =.*$second" \
-	"$message; check second observer counter value"
-    gdb_test "print observer_test_third_observer" \
-	".\[0-9\]+ =.*$third" \
-	"$message; check third observer counter value"
-}
-
-proc reset_counters { message } {
-    gdb_test_no_output "set variable observer_test_first_observer = 0" \
-	"$message; reset first observer counter"
-    gdb_test_no_output "set variable observer_test_second_observer = 0" \
-	"$message; reset second observer counter"
-    gdb_test_no_output "set variable observer_test_third_observer = 0" \
-	"$message; reset third observer counter"
-}
-
-proc test_notifications { first second third message args } {
-    # Do any initialization
-    for {set i 0} {$i < [llength $args]} {incr i} {
-	[lindex $args $i] $message
-    }
-    reset_counters $message
-    # Call observer_notify_test_notification.  Note that this procedure
-    # takes one argument, but this argument is ignored by the observer
-    # callbacks we have installed.  So we just pass an arbitrary value.
-    gdb_test_no_output "call observer_notify_test_notification (0)" \
-	"$message; sending notification"
-    check_counters $first $second $third $message
-}
-
-proc test_observer {} {
-    # First, try sending a notification without any observer attached.
-    test_notifications 0 0 0 "no observer attached"
-
-    # Now, attach one observer, and send a notification.
-    test_notifications 0 1 0 "second observer attached" \
-	attach_second_observer
-
-    # Remove the observer, and send a notification.
-    test_notifications 0 0 0 "second observer detached" \
-	detach_second_observer
-
-    # With a new observer.
-    test_notifications 1 0 0 "1st observer added" \
-	attach_first_observer
-
-    # With 2 observers.
-    test_notifications 1 1 0 "2nd observer added" \
-	attach_second_observer
-
-    # With 3 observers.
-    test_notifications 1 1 1 "3rd observer added" \
-	attach_third_observer
-
-    # Remove middle observer.
-    test_notifications 1 0 1 "2nd observer removed" \
-	detach_second_observer
-
-    # Remove first observer.
-    test_notifications 0 0 1 "1st observer removed" \
-	detach_first_observer
-
-    # Remove last observer.
-    test_notifications 0 0 0 "3rd observer removed" \
-	detach_third_observer
-
-    # Go back to 3 observers, and remove them in a different order...
-    test_notifications 1 1 1 "three observers added" \
-	attach_first_observer \
-	attach_second_observer \
-	attach_third_observer 
-
-    # Remove the third observer.
-    test_notifications 1 1 0 "third observer removed" \
-	detach_third_observer
-
-    # Remove the second observer.
-    test_notifications 1 0 0 "second observer removed" \
-	detach_second_observer
-
-    # Remove the first observer, no more observers.
-    test_notifications 0 0 0 "first observer removed" \
-	detach_first_observer
-
-    return 0
-}
-
-do_self_tests captured_main test_observer
diff --git a/gdb/thread.c b/gdb/thread.c
index 36cfcdd632..eda847dbbb 100644
--- a/gdb/thread.c
+++ b/gdb/thread.c
@@ -207,7 +207,7 @@  set_thread_exited (thread_info *tp, int silent)
 
   if (tp->state != THREAD_EXITED)
     {
-      observer_notify_thread_exit (tp, silent);
+      gdb::observers::thread_exit.notify (tp, silent);
 
       /* Tag it as exited.  */
       tp->state = THREAD_EXITED;
@@ -299,7 +299,7 @@  add_thread_silent (ptid_t ptid)
 	  tp->state = THREAD_STOPPED;
 	  switch_to_thread (ptid);
 
-	  observer_notify_new_thread (tp);
+	  gdb::observers::new_thread.notify (tp);
 
 	  /* All done.  */
 	  return tp;
@@ -310,7 +310,7 @@  add_thread_silent (ptid_t ptid)
     }
 
   tp = new_thread (inf, ptid);
-  observer_notify_new_thread (tp);
+  gdb::observers::new_thread.notify (tp);
 
   return tp;
 }
@@ -866,7 +866,7 @@  thread_change_ptid (ptid_t old_ptid, ptid_t new_ptid)
   tp = find_thread_ptid (old_ptid);
   tp->ptid = new_ptid;
 
-  observer_notify_thread_ptid_changed (old_ptid, new_ptid);
+  gdb::observers::thread_ptid_changed.notify (old_ptid, new_ptid);
 }
 
 /* See gdbthread.h.  */
@@ -946,7 +946,7 @@  set_running (ptid_t ptid, int running)
 	any_started = 1;
     }
   if (any_started)
-    observer_notify_target_resumed (ptid);
+    gdb::observers::target_resumed.notify (ptid);
 }
 
 static int
@@ -1045,7 +1045,7 @@  set_stop_requested (ptid_t ptid, int stop)
   /* Call the stop requested observer so other components of GDB can
      react to this request.  */
   if (stop)
-    observer_notify_thread_stop_requested (ptid);
+    gdb::observers::thread_stop_requested.notify (ptid);
 }
 
 void
@@ -1082,7 +1082,7 @@  finish_thread_state (ptid_t ptid)
     }
 
   if (any_started)
-    observer_notify_target_resumed (ptid);
+    gdb::observers::target_resumed.notify (ptid);
 }
 
 void
@@ -1831,8 +1831,8 @@  thread_command (const char *tidstr, int from_tty)
 	}
       else
 	{
-	  observer_notify_user_selected_context_changed (USER_SELECTED_THREAD
-							 | USER_SELECTED_FRAME);
+	  gdb::observers::user_selected_context_changed.notify
+	    (USER_SELECTED_THREAD | USER_SELECTED_FRAME);
 	}
     }
 }
diff --git a/gdb/top.c b/gdb/top.c
index a6166bd280..6991aee8dd 100644
--- a/gdb/top.c
+++ b/gdb/top.c
@@ -1932,7 +1932,7 @@  static void
 set_gdb_datadir (const char *args, int from_tty, struct cmd_list_element *c)
 {
   set_gdb_data_directory (staged_gdb_datadir);
-  observer_notify_gdb_datadir_changed ();
+  gdb::observers::gdb_datadir_changed.notify ();
 }
 
 /* "show" command for the gdb_datadir configuration variable.  */
diff --git a/gdb/tracepoint.c b/gdb/tracepoint.c
index f34f103875..6f2bc83799 100644
--- a/gdb/tracepoint.c
+++ b/gdb/tracepoint.c
@@ -315,7 +315,7 @@  delete_trace_state_variable (const char *name)
   for (ix = 0; VEC_iterate (tsv_s, tvariables, ix, tsv); ++ix)
     if (strcmp (name, tsv->name) == 0)
       {
-	observer_notify_tsv_deleted (tsv);
+	gdb::observers::tsv_deleted.notify (tsv);
 
 	xfree ((void *)tsv->name);
 	VEC_unordered_remove (tsv_s, tvariables, ix);
@@ -390,7 +390,7 @@  trace_variable_command (const char *args, int from_tty)
       if (tsv->initial_value != initval)
 	{
 	  tsv->initial_value = initval;
-	  observer_notify_tsv_modified (tsv);
+	  gdb::observers::tsv_modified.notify (tsv);
 	}
       printf_filtered (_("Trace state variable $%s "
 			 "now has initial value %s.\n"),
@@ -402,7 +402,7 @@  trace_variable_command (const char *args, int from_tty)
   tsv = create_trace_state_variable (name.c_str ());
   tsv->initial_value = initval;
 
-  observer_notify_tsv_created (tsv);
+  gdb::observers::tsv_created.notify (tsv);
 
   printf_filtered (_("Trace state variable $%s "
 		     "created, with initial value %s.\n"),
@@ -417,7 +417,7 @@  delete_trace_variable_command (const char *args, int from_tty)
       if (query (_("Delete all trace state variables? ")))
 	VEC_free (tsv_s, tvariables);
       dont_repeat ();
-      observer_notify_tsv_deleted (NULL);
+      gdb::observers::tsv_deleted.notify (NULL);
       return;
     }
 
@@ -1659,7 +1659,7 @@  start_tracing (const char *notes)
 					  loc->gdbarch);
 
       if (bp_location_downloaded)
-	observer_notify_breakpoint_modified (b);
+	gdb::observers::breakpoint_modified.notify (b);
     }
   VEC_free (breakpoint_p, tp_vec);
 
@@ -2175,7 +2175,7 @@  tfind_1 (enum trace_find_type type, int num,
   set_tracepoint_num (tp ? tp->number : target_tracept);
 
   if (target_frameno != get_traceframe_number ())
-    observer_notify_traceframe_changed (target_frameno, tracepoint_number);
+    gdb::observers::traceframe_changed.notify (target_frameno, tracepoint_number);
 
   set_current_traceframe (target_frameno);
 
@@ -3240,7 +3240,7 @@  merge_uploaded_tracepoints (struct uploaded_tp **uploaded_tps)
   /* Notify 'breakpoint-modified' observer that at least one of B's
      locations was changed.  */
   for (ix = 0; VEC_iterate (breakpoint_p, modified_tp, ix, b); ix++)
-    observer_notify_breakpoint_modified (b);
+    gdb::observers::breakpoint_modified.notify (b);
 
   VEC_free (breakpoint_p, modified_tp);
   free_uploaded_tps (uploaded_tps);
@@ -3287,7 +3287,7 @@  create_tsv_from_upload (struct uploaded_tsv *utsv)
   tsv->initial_value = utsv->initial_value;
   tsv->builtin = utsv->builtin;
 
-  observer_notify_tsv_created (tsv);
+  gdb::observers::tsv_created.notify (tsv);
 
   return tsv;
 }
diff --git a/gdb/tui/tui-hooks.c b/gdb/tui/tui-hooks.c
index 84e416e756..ba87aec2e1 100644
--- a/gdb/tui/tui-hooks.c
+++ b/gdb/tui/tui-hooks.c
@@ -204,13 +204,20 @@  tui_normal_stop (struct bpstats *bs, int print_frame)
 }
 
 /* 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;
+static gdb::observers::observable<struct breakpoint *>::token_type
+  tui_bp_created_observer;
+static gdb::observers::observable<struct breakpoint *>::token_type
+  tui_bp_deleted_observer;
+static gdb::observers::observable<struct breakpoint *>::token_type
+  tui_bp_modified_observer;
+static gdb::observers::observable<struct inferior *>::token_type
+  tui_inferior_exit_observer;
+static gdb::observers::observable<const char *>::token_type
+  tui_before_prompt_observer;
+static gdb::observers::observable<struct bpstats *, int>::token_type
+  tui_normal_stop_observer;
+static gdb::observers::observable<struct frame_info *, int>::token_type
+  tui_register_changed_observer;
 
 /* Install the TUI specific hooks.  */
 void
@@ -225,19 +232,19 @@  tui_install_hooks (void)
 
   /* Install the event hooks.  */
   tui_bp_created_observer
-    = observer_attach_breakpoint_created (tui_event_create_breakpoint);
+    = gdb::observers::breakpoint_created.attach (tui_event_create_breakpoint);
   tui_bp_deleted_observer
-    = observer_attach_breakpoint_deleted (tui_event_delete_breakpoint);
+    = gdb::observers::breakpoint_deleted.attach (tui_event_delete_breakpoint);
   tui_bp_modified_observer
-    = observer_attach_breakpoint_modified (tui_event_modify_breakpoint);
+    = gdb::observers::breakpoint_modified.attach (tui_event_modify_breakpoint);
   tui_inferior_exit_observer
-    = observer_attach_inferior_exit (tui_inferior_exit);
+    = gdb::observers::inferior_exit.attach (tui_inferior_exit);
   tui_before_prompt_observer
-    = observer_attach_before_prompt (tui_before_prompt);
+    = gdb::observers::before_prompt.attach (tui_before_prompt);
   tui_normal_stop_observer
-    = observer_attach_normal_stop (tui_normal_stop);
+    = gdb::observers::normal_stop.attach (tui_normal_stop);
   tui_register_changed_observer
-    = observer_attach_register_changed (tui_register_changed);
+    = gdb::observers::register_changed.attach (tui_register_changed);
 }
 
 /* Remove the TUI specific hooks.  */
@@ -247,25 +254,25 @@  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;
+  gdb::observers::breakpoint_created.detach (tui_bp_created_observer);
+  tui_bp_created_observer = gdb::observers::breakpoint_created.null_token;
+  gdb::observers::breakpoint_deleted.detach (tui_bp_deleted_observer);
+  tui_bp_deleted_observer = gdb::observers::breakpoint_deleted.null_token;
+  gdb::observers::breakpoint_modified.detach (tui_bp_modified_observer);
+  tui_bp_modified_observer = gdb::observers::breakpoint_modified.null_token;
+  gdb::observers::inferior_exit.detach (tui_inferior_exit_observer);
+  tui_inferior_exit_observer = gdb::observers::inferior_exit.null_token;
+  gdb::observers::before_prompt.detach (tui_before_prompt_observer);
+  tui_before_prompt_observer = gdb::observers::before_prompt.null_token;
+  gdb::observers::normal_stop.detach (tui_normal_stop_observer);
+  tui_normal_stop_observer = gdb::observers::normal_stop.null_token;
+  gdb::observers::register_changed.detach (tui_register_changed_observer);
+  tui_register_changed_observer = gdb::observers::register_changed.null_token;
 }
 
 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 3c87198696..1bb7a17a63 100644
--- a/gdb/tui/tui-interp.c
+++ b/gdb/tui/tui-interp.c
@@ -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);
 }
diff --git a/gdb/valops.c b/gdb/valops.c
index e038c04fd1..5536a624fc 100644
--- a/gdb/valops.c
+++ b/gdb/valops.c
@@ -1177,7 +1177,7 @@  value_assign (struct value *toval, struct value *fromval)
 	      }
 	  }
 
-	observer_notify_register_changed (frame, value_reg);
+	gdb::observers::register_changed.notify (frame, value_reg);
 	break;
       }
 
@@ -1208,7 +1208,7 @@  value_assign (struct value *toval, struct value *fromval)
     case lval_register:
     case lval_computed:
 
-      observer_notify_target_changed (&current_target);
+      gdb::observers::target_changed.notify (&current_target);
 
       /* Having destroyed the frame cache, restore the selected
 	 frame.  */