Move add_location(sal) to base_breakpoint

After the previous patches, only base_breakpoint subclasses use
add_location(sal), so we can move it to base_breakpoint (a.k.a. base
class for code breakpoints).

This requires a few casts here and there, but always at spots where
you can see from context what the breakpoint's type actually is.

I inlined new_single_step_breakpoint into its only caller exactly for
this reason.

I did try to propagate more use of base_breakpoint to avoid casts, but
that turned out unwieldy for this patch.

Change-Id: I49d959322b0fdce5a88a216bb44730fc5dd7c6f8

5 files changed, 31 insertions, 37 deletions

diff --git a/gdb/breakpoint.c b/gdb/breakpoint.c
index bfb5cd3..b6e3183 100644
--- a/gdb/breakpoint.c
+++ b/gdb/breakpoint.c
@@ -87,7 +87,7 @@
 static void map_breakpoint_numbers (const char *,
 				    gdb::function_view<void (breakpoint *)>);
 
-static void breakpoint_re_set_default (struct breakpoint *);
+static void breakpoint_re_set_default (base_breakpoint *);
 
 static void
   create_sals_from_location_default (struct event_location *location,
@@ -5860,10 +5860,10 @@ bpstat_run_callbacks (bpstat *bs_head)
 	  handle_jit_event (bs->bp_location_at->address);
 	  break;
 	case bp_gnu_ifunc_resolver:
-	  gnu_ifunc_resolver_stop (b);
+	  gnu_ifunc_resolver_stop ((base_breakpoint *) b);
 	  break;
 	case bp_gnu_ifunc_resolver_return:
-	  gnu_ifunc_resolver_return_stop (b);
+	  gnu_ifunc_resolver_return_stop ((base_breakpoint *) b);
 	  break;
 	}
     }
@@ -7867,24 +7867,6 @@ enable_breakpoints_after_startup (void)
   breakpoint_re_set ();
 }
 
-/* Create a new single-step breakpoint for thread THREAD, with no
-   locations.  */
-
-static struct breakpoint *
-new_single_step_breakpoint (int thread, struct gdbarch *gdbarch)
-{
-  std::unique_ptr<breakpoint> b (new momentary_breakpoint (gdbarch,
-							   bp_single_step));
-
-  b->disposition = disp_donttouch;
-  b->frame_id = null_frame_id;
-
-  b->thread = thread;
-  gdb_assert (b->thread != 0);
-
-  return add_to_breakpoint_chain (std::move (b));
-}
-
 /* Allocate a new momentary breakpoint.  */
 
 static momentary_breakpoint *
@@ -8057,7 +8039,7 @@ handle_automatic_hardware_breakpoints (bp_location *bl)
 }
 
 bp_location *
-breakpoint::add_location (const symtab_and_line &sal)
+base_breakpoint::add_location (const symtab_and_line &sal)
 {
   struct bp_location *new_loc, **tmp;
   CORE_ADDR adjusted_address;
@@ -12476,7 +12458,7 @@ hoist_existing_locations (struct breakpoint *b, struct program_space *pspace)
    untouched.  */
 
 void
-update_breakpoint_locations (struct breakpoint *b,
+update_breakpoint_locations (base_breakpoint *b,
 			     struct program_space *filter_pspace,
 			     gdb::array_view<const symtab_and_line> sals,
 			     gdb::array_view<const symtab_and_line> sals_end)
@@ -12684,7 +12666,7 @@ location_to_sals (struct breakpoint *b, struct event_location *location,
    locations.  */
 
 static void
-breakpoint_re_set_default (struct breakpoint *b)
+breakpoint_re_set_default (base_breakpoint *b)
 {
   struct program_space *filter_pspace = current_program_space;
   std::vector<symtab_and_line> expanded, expanded_end;
@@ -13395,15 +13377,26 @@ insert_single_step_breakpoint (struct gdbarch *gdbarch,
 
   if (tp->control.single_step_breakpoints == NULL)
     {
+      std::unique_ptr<breakpoint> b
+	(new momentary_breakpoint (gdbarch, bp_single_step));
+
+      b->disposition = disp_donttouch;
+
+      b->thread = tp->global_num;
+      gdb_assert (b->thread != 0);
+
       tp->control.single_step_breakpoints
-	= new_single_step_breakpoint (tp->global_num, gdbarch);
+	= add_to_breakpoint_chain (std::move (b));
     }
 
   sal = find_pc_line (pc, 0);
   sal.pc = pc;
   sal.section = find_pc_overlay (pc);
   sal.explicit_pc = 1;
-  tp->control.single_step_breakpoints->add_location (sal);
+
+  auto *ss_bp
+    = static_cast<momentary_breakpoint *> (tp->control.single_step_breakpoints);
+  ss_bp->add_location (sal);
 
   update_global_location_list (UGLL_INSERT);
 }
diff --git a/gdb/breakpoint.h b/gdb/breakpoint.h
index af69af6..807c97a 100644
--- a/gdb/breakpoint.h
+++ b/gdb/breakpoint.h
@@ -733,9 +733,6 @@ struct breakpoint
     /* Nothing to do.  */
   }
 
-  /* Add a location for SAL to this breakpoint.  */
-  bp_location *add_location (const symtab_and_line &sal);
-
   /* Return a range of this breakpoint's locations.  */
   bp_location_range locations () const;
 
@@ -874,6 +871,9 @@ struct base_breakpoint : public breakpoint
 
   ~base_breakpoint () override = 0;
 
+  /* Add a location for SAL to this breakpoint.  */
+  bp_location *add_location (const symtab_and_line &sal);
+
   void re_set () override;
   int insert_location (struct bp_location *) override;
   int remove_location (struct bp_location *,
@@ -1383,7 +1383,7 @@ extern void until_break_command (const char *, int, int);
 /* Initialize a struct bp_location.  */
 
 extern void update_breakpoint_locations
-  (struct breakpoint *b,
+  (base_breakpoint *b,
    struct program_space *filter_pspace,
    gdb::array_view<const symtab_and_line> sals,
    gdb::array_view<const symtab_and_line> sals_end);
diff --git a/gdb/elfread.c b/gdb/elfread.c
index b136c60..2720372 100644
--- a/gdb/elfread.c
+++ b/gdb/elfread.c
@@ -927,7 +927,7 @@ elf_gnu_ifunc_resolve_addr (struct gdbarch *gdbarch, CORE_ADDR pc)
 /* Handle inferior hit of bp_gnu_ifunc_resolver, see its definition.  */
 
 static void
-elf_gnu_ifunc_resolver_stop (struct breakpoint *b)
+elf_gnu_ifunc_resolver_stop (base_breakpoint *b)
 {
   struct breakpoint *b_return;
   struct frame_info *prev_frame = get_prev_frame (get_current_frame ());
@@ -978,7 +978,7 @@ elf_gnu_ifunc_resolver_stop (struct breakpoint *b)
 /* Handle inferior hit of bp_gnu_ifunc_resolver_return, see its definition.  */
 
 static void
-elf_gnu_ifunc_resolver_return_stop (struct breakpoint *b)
+elf_gnu_ifunc_resolver_return_stop (base_breakpoint *b)
 {
   thread_info *thread = inferior_thread ();
   struct gdbarch *gdbarch = get_frame_arch (get_current_frame ());
@@ -1008,7 +1008,7 @@ elf_gnu_ifunc_resolver_return_stop (struct breakpoint *b)
 			    "gnu-indirect-function breakpoint type %d"),
 			  (int) b->type);
 	}
-      b = b_next;
+      b = (base_breakpoint *) b_next;
     }
   gdb_assert (b->type == bp_gnu_ifunc_resolver);
   gdb_assert (b->loc->next == NULL);
diff --git a/gdb/minsyms.c b/gdb/minsyms.c
index cbd0ad2..217ee04 100644
--- a/gdb/minsyms.c
+++ b/gdb/minsyms.c
@@ -1019,7 +1019,7 @@ stub_gnu_ifunc_resolve_name (const char *function_name,
 /* See elf_gnu_ifunc_resolver_stop for its real implementation.  */
 
 static void
-stub_gnu_ifunc_resolver_stop (struct breakpoint *b)
+stub_gnu_ifunc_resolver_stop (base_breakpoint *b)
 {
   internal_error (__FILE__, __LINE__,
 		  _("elf_gnu_ifunc_resolver_stop cannot be reached."));
@@ -1028,7 +1028,7 @@ stub_gnu_ifunc_resolver_stop (struct breakpoint *b)
 /* See elf_gnu_ifunc_resolver_return_stop for its real implementation.  */
 
 static void
-stub_gnu_ifunc_resolver_return_stop (struct breakpoint *b)
+stub_gnu_ifunc_resolver_return_stop (base_breakpoint *b)
 {
   internal_error (__FILE__, __LINE__,
 		  _("elf_gnu_ifunc_resolver_return_stop cannot be reached."));
diff --git a/gdb/symtab.h b/gdb/symtab.h
index b1cf84f..5218be5 100644
--- a/gdb/symtab.h
+++ b/gdb/symtab.h
@@ -55,6 +55,7 @@ struct obj_section;
 struct cmd_list_element;
 class probe;
 struct lookup_name_info;
+struct base_breakpoint;
 
 /* How to match a lookup name against a symbol search name.  */
 enum class symbol_name_match_type
@@ -2227,10 +2228,10 @@ struct gnu_ifunc_fns
 				 CORE_ADDR *function_address_p);
 
   /* See elf_gnu_ifunc_resolver_stop for its real implementation.  */
-  void (*gnu_ifunc_resolver_stop) (struct breakpoint *b);
+  void (*gnu_ifunc_resolver_stop) (base_breakpoint *b);
 
   /* See elf_gnu_ifunc_resolver_return_stop for its real implementation.  */
-  void (*gnu_ifunc_resolver_return_stop) (struct breakpoint *b);
+  void (*gnu_ifunc_resolver_return_stop) (base_breakpoint *b);
 };
 
 #define gnu_ifunc_resolve_addr gnu_ifunc_fns_p->gnu_ifunc_resolve_addr