[RFA 12/13] Introduce gdb_breakpoint_up

[Tom Tromey <tom at tromey dot com>]

This introduces gdb_breakpoint_up, a unique_ptr typedef that owns a
breakpoint.  It then changes set_momentary_breakpoint to return a
gdb_breakpoint_up and fixes up the fallout.  This then allows the
removal of make_cleanup_delete_breakpoint.

Once breakpoints are fully C++-ified, this typedef can be removed in
favor of a plain std::unique_ptr.

gdb/ChangeLog
2017-11-02  Tom Tromey  <tom@tromey.com>

	* breakpoint.c (set_momentary_breakpoint): Return
	gdb_breakpoint_up.
	(until_break_command): Update.
	(new_until_break_fsm): Change argument types to
	gdb_breakpoint_up.
	(set_momentary_breakpoint_at_pc): Return gdb_breakpoint_up.
	(do_delete_breakpoint_cleanup, make_cleanup_delete_breakpoint):
	Remove.
	* infcmd.c (finish_forward): Update.
	* breakpoint.h (set_momentary_breakpoint)
	(set_momentary_breakpoint_at_pc): Return gdb_breakpoint_up.
	(make_cleanup_delete_breakpoint): Remove.
	(struct gdb_breakpoint_deleter): New.
	(gdb_breakpoint_up): New typedef.
	* infrun.c (insert_step_resume_breakpoint_at_sal_1): Update.
	(insert_exception_resume_breakpoint): Update.
	(insert_exception_resume_from_probe): Update.
	(insert_longjmp_resume_breakpoint): Update.
	* arm-linux-tdep.c (arm_linux_copy_svc): Update.
	* elfread.c (elf_gnu_ifunc_resolver_stop): Update.
	* infcall.c (call_function_by_hand_dummy): Update
---
 gdb/ChangeLog        | 24 ++++++++++++++++++++++++
 gdb/arm-linux-tdep.c |  2 +-
 gdb/breakpoint.c     | 35 +++++++++++------------------------
 gdb/breakpoint.h     | 21 +++++++++++++++------
 gdb/elfread.c        |  7 ++++---
 gdb/infcall.c        |  5 +++--
 gdb/infcmd.c         |  2 +-
 gdb/infrun.c         |  9 +++++----
 8 files changed, 64 insertions(+), 41 deletions(-)

diff --git a/gdb/arm-linux-tdep.c b/gdb/arm-linux-tdep.c
index 525474c4db..7769c9c2e2 100644
--- a/gdb/arm-linux-tdep.c
+++ b/gdb/arm-linux-tdep.c
@@ -1020,7 +1020,7 @@ arm_linux_copy_svc (struct gdbarch *gdbarch, struct regcache *regs,
 	{
 	  inferior_thread ()->control.step_resume_breakpoint
 	    = set_momentary_breakpoint (gdbarch, sal, get_frame_id (frame),
-					bp_step_resume);
+					bp_step_resume).release ();
 
 	  /* set_momentary_breakpoint invalidates FRAME.  */
 	  frame = NULL;
diff --git a/gdb/breakpoint.c b/gdb/breakpoint.c
index 61e41283b1..7237e81b41 100644
--- a/gdb/breakpoint.c
+++ b/gdb/breakpoint.c
@@ -8582,7 +8582,7 @@ new_single_step_breakpoint (int thread, struct gdbarch *gdbarch)
    SAL.  If FRAME_ID is valid, the breakpoint is restricted to that
    frame.  */
 
-struct breakpoint *
+gdb_breakpoint_up
 set_momentary_breakpoint (struct gdbarch *gdbarch, struct symtab_and_line sal,
 			  struct frame_id frame_id, enum bptype type)
 {
@@ -8605,7 +8605,7 @@ set_momentary_breakpoint (struct gdbarch *gdbarch, struct symtab_and_line sal,
 
   update_global_location_list_nothrow (UGLL_MAY_INSERT);
 
-  return b;
+  return gdb_breakpoint_up (b);
 }
 
 /* Make a momentary breakpoint based on the master breakpoint ORIG.
@@ -8658,7 +8658,7 @@ clone_momentary_breakpoint (struct breakpoint *orig)
   return momentary_breakpoint_from_master (orig, orig->type, orig->ops, 0);
 }
 
-struct breakpoint *
+gdb_breakpoint_up
 set_momentary_breakpoint_at_pc (struct gdbarch *gdbarch, CORE_ADDR pc,
 				enum bptype type)
 {
@@ -11146,8 +11146,8 @@ static struct thread_fsm_ops until_break_fsm_ops =
 
 static struct until_break_fsm *
 new_until_break_fsm (struct interp *cmd_interp, int thread,
-		     struct breakpoint *location_breakpoint,
-		     struct breakpoint *caller_breakpoint)
+		     gdb_breakpoint_up &&location_breakpoint,
+		     gdb_breakpoint_up &&caller_breakpoint)
 {
   struct until_break_fsm *sm;
 
@@ -11155,8 +11155,8 @@ new_until_break_fsm (struct interp *cmd_interp, int thread,
   thread_fsm_ctor (&sm->thread_fsm, &until_break_fsm_ops, cmd_interp);
 
   sm->thread = thread;
-  sm->location_breakpoint = location_breakpoint;
-  sm->caller_breakpoint = caller_breakpoint;
+  sm->location_breakpoint = location_breakpoint.release ();
+  sm->caller_breakpoint = caller_breakpoint.release ();
 
   return sm;
 }
@@ -11219,8 +11219,6 @@ until_break_command (const char *arg, int from_tty, int anywhere)
   struct gdbarch *frame_gdbarch;
   struct frame_id stack_frame_id;
   struct frame_id caller_frame_id;
-  struct breakpoint *location_breakpoint;
-  struct breakpoint *caller_breakpoint = NULL;
   struct cleanup *old_chain;
   int thread;
   struct thread_info *tp;
@@ -11269,6 +11267,7 @@ until_break_command (const char *arg, int from_tty, int anywhere)
   /* Keep within the current frame, or in frames called by the current
      one.  */
 
+  gdb_breakpoint_up caller_breakpoint;
   if (frame_id_p (caller_frame_id))
     {
       struct symtab_and_line sal2;
@@ -11281,7 +11280,6 @@ until_break_command (const char *arg, int from_tty, int anywhere)
 						    sal2,
 						    caller_frame_id,
 						    bp_until);
-      make_cleanup_delete_breakpoint (caller_breakpoint);
 
       set_longjmp_breakpoint (tp, caller_frame_id);
       make_cleanup (delete_longjmp_breakpoint_cleanup, &thread);
@@ -11290,6 +11288,7 @@ until_break_command (const char *arg, int from_tty, int anywhere)
   /* set_momentary_breakpoint could invalidate FRAME.  */
   frame = NULL;
 
+  gdb_breakpoint_up location_breakpoint;
   if (anywhere)
     /* If the user told us to continue until a specified location,
        we don't specify a frame at which we need to stop.  */
@@ -11300,10 +11299,10 @@ until_break_command (const char *arg, int from_tty, int anywhere)
        only at the very same frame.  */
     location_breakpoint = set_momentary_breakpoint (frame_gdbarch, sal,
 						    stack_frame_id, bp_until);
-  make_cleanup_delete_breakpoint (location_breakpoint);
 
   sm = new_until_break_fsm (command_interp (), tp->global_num,
-			    location_breakpoint, caller_breakpoint);
+			    std::move (location_breakpoint),
+			    std::move (caller_breakpoint));
   tp->thread_fsm = &sm->thread_fsm;
 
   discard_cleanups (old_chain);
@@ -13366,18 +13365,6 @@ delete_breakpoint (struct breakpoint *bpt)
   delete bpt;
 }
 
-static void
-do_delete_breakpoint_cleanup (void *b)
-{
-  delete_breakpoint ((struct breakpoint *) b);
-}
-
-struct cleanup *
-make_cleanup_delete_breakpoint (struct breakpoint *b)
-{
-  return make_cleanup (do_delete_breakpoint_cleanup, b);
-}
-
 /* Iterator function to call a user-provided callback function once
    for each of B and its related breakpoints.  */
 
diff --git a/gdb/breakpoint.h b/gdb/breakpoint.h
index 69b63ea932..494d05aa7d 100644
--- a/gdb/breakpoint.h
+++ b/gdb/breakpoint.h
@@ -1223,10 +1223,23 @@ extern void breakpoint_re_set (void);
 
 extern void breakpoint_re_set_thread (struct breakpoint *);
 
-extern struct breakpoint *set_momentary_breakpoint
+extern void delete_breakpoint (struct breakpoint *);
+
+struct gdb_breakpoint_deleter
+{
+  void operator() (struct breakpoint *b) const
+  {
+    delete_breakpoint (b);
+  }
+};
+
+typedef std::unique_ptr<struct breakpoint, gdb_breakpoint_deleter>
+    gdb_breakpoint_up;
+
+extern gdb_breakpoint_up set_momentary_breakpoint
   (struct gdbarch *, struct symtab_and_line, struct frame_id, enum bptype);
 
-extern struct breakpoint *set_momentary_breakpoint_at_pc
+extern gdb_breakpoint_up set_momentary_breakpoint_at_pc
   (struct gdbarch *, CORE_ADDR pc, enum bptype type);
 
 extern struct breakpoint *clone_momentary_breakpoint (struct breakpoint *bpkt);
@@ -1235,10 +1248,6 @@ extern void set_ignore_count (int, int, int);
 
 extern void breakpoint_init_inferior (enum inf_context);
 
-extern struct cleanup *make_cleanup_delete_breakpoint (struct breakpoint *);
-
-extern void delete_breakpoint (struct breakpoint *);
-
 extern void breakpoint_auto_delete (bpstat);
 
 typedef void (*walk_bp_location_callback) (struct bp_location *, void *);
diff --git a/gdb/elfread.c b/gdb/elfread.c
index 4e110716c3..cdef5a8c59 100644
--- a/gdb/elfread.c
+++ b/gdb/elfread.c
@@ -923,9 +923,10 @@ elf_gnu_ifunc_resolver_stop (struct breakpoint *b)
       sal.pc = prev_pc;
       sal.section = find_pc_overlay (sal.pc);
       sal.explicit_pc = 1;
-      b_return = set_momentary_breakpoint (get_frame_arch (prev_frame), sal,
-					   prev_frame_id,
-					   bp_gnu_ifunc_resolver_return);
+      b_return
+	= set_momentary_breakpoint (get_frame_arch (prev_frame), sal,
+				    prev_frame_id,
+				    bp_gnu_ifunc_resolver_return).release ();
 
       /* set_momentary_breakpoint invalidates PREV_FRAME.  */
       prev_frame = NULL;
diff --git a/gdb/infcall.c b/gdb/infcall.c
index 03749f3dc2..b06758085d 100644
--- a/gdb/infcall.c
+++ b/gdb/infcall.c
@@ -1100,8 +1100,9 @@ call_function_by_hand_dummy (struct value *function,
     /* Sanity.  The exact same SP value is returned by
        PUSH_DUMMY_CALL, saved as the dummy-frame TOS, and used by
        dummy_id to form the frame ID's stack address.  */
-    breakpoint *bpt = set_momentary_breakpoint (gdbarch, sal,
-						dummy_id, bp_call_dummy);
+    breakpoint *bpt
+      = set_momentary_breakpoint (gdbarch, sal,
+				  dummy_id, bp_call_dummy).release ();
 
     /* set_momentary_breakpoint invalidates FRAME.  */
     frame = NULL;
diff --git a/gdb/infcmd.c b/gdb/infcmd.c
index 669631bdb4..49349c169e 100644
--- a/gdb/infcmd.c
+++ b/gdb/infcmd.c
@@ -1986,7 +1986,7 @@ finish_forward (struct finish_command_fsm *sm, struct frame_info *frame)
 
   sm->breakpoint = set_momentary_breakpoint (gdbarch, sal,
 					     get_stack_frame_id (frame),
-					     bp_finish);
+					     bp_finish).release ();
 
   /* set_momentary_breakpoint invalidates FRAME.  */
   frame = NULL;
diff --git a/gdb/infrun.c b/gdb/infrun.c
index ef5a505d89..d425664957 100644
--- a/gdb/infrun.c
+++ b/gdb/infrun.c
@@ -7402,7 +7402,7 @@ insert_step_resume_breakpoint_at_sal_1 (struct gdbarch *gdbarch,
 			paddress (gdbarch, sr_sal.pc));
 
   inferior_thread ()->control.step_resume_breakpoint
-    = set_momentary_breakpoint (gdbarch, sr_sal, sr_id, sr_type);
+    = set_momentary_breakpoint (gdbarch, sr_sal, sr_id, sr_type).release ();
 }
 
 void
@@ -7491,7 +7491,7 @@ insert_longjmp_resume_breakpoint (struct gdbarch *gdbarch, CORE_ADDR pc)
 			paddress (gdbarch, pc));
 
   inferior_thread ()->control.exception_resume_breakpoint =
-    set_momentary_breakpoint_at_pc (gdbarch, pc, bp_longjmp_resume);
+    set_momentary_breakpoint_at_pc (gdbarch, pc, bp_longjmp_resume).release ();
 }
 
 /* Insert an exception resume breakpoint.  TP is the thread throwing
@@ -7526,7 +7526,8 @@ insert_exception_resume_breakpoint (struct thread_info *tp,
 				(unsigned long) handler);
 
 	  bp = set_momentary_breakpoint_at_pc (get_frame_arch (frame),
-					       handler, bp_exception_resume);
+					       handler,
+					       bp_exception_resume).release ();
 
 	  /* set_momentary_breakpoint_at_pc invalidates FRAME.  */
 	  frame = NULL;
@@ -7567,7 +7568,7 @@ insert_exception_resume_from_probe (struct thread_info *tp,
 				  handler));
 
   bp = set_momentary_breakpoint_at_pc (get_frame_arch (frame),
-				       handler, bp_exception_resume);
+				       handler, bp_exception_resume).release ();
   bp->thread = tp->global_num;
   inferior_thread ()->control.exception_resume_breakpoint = bp;
 }
-- 
2.13.6