Convert observers to C++

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

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

Regression tested on the buildbot.

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

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

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

	* observer.texi: Remove.

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

	* gdb.gdb/observer.exp: Remove.

1 files changed, 235 insertions, 0 deletions

diff --git a/gdb/observable.h b/gdb/observable.h
new file mode 100644
index 0000000..34447b9
--- /dev/null
+++ b/gdb/observable.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 */