C++ify breakpoint class hierarchy (destructors only)

Breakpoints are currently in a limbo state between C and C++.  There is
a pseudo class hierarchy implemented using struct fields.  Taking
watchpoint as an example:

  struct watchpoint
  {
    /* The base class.  */
    struct breakpoint base;

    ...
  }

and it is instantianted with "new watchpoint ()".  When destroyed, a
destructor is first invoked through the breakpoint_ops, and then the
memory is freed by calling delete through a pointer to breakpoint.
Address sanitizer complains about this, for example, because we new and
delete the same memory using different types.

This patch takes the logical step of making breakpoint subclasses extend
the breakpoint class for real, and converts their destructors to actual
C++ destructors.

Regtested on the buildbot.

gdb/ChangeLog:

	* breakpoint.h (struct breakpoint_ops) <dtor>: Remove.
	(struct breakpoint) <~breakpoint>: New.
	(struct watchpoint): Inherit from breakpoint.
	<~watchpoint>: New.
	<base>: Remove.
	(struct tracepoint): Inherit from breakpoint.
	<base>: Remove.
	* breakpoint.c (longjmp_breakpoint_ops): Remove.
	(struct longjmp_breakpoint): Inherit from breakpoint.
	<~longjmp_breakpoint>: New.
	<base>: Remove.
	(new_breakpoint_from_type): Remove casts.
	(watchpoint_in_thread_scope): Remove reference to base field.
	(watchpoint_del_at_next_stop): Likewise.
	(update_watchpoint): Likewise.
	(watchpoint_check): Likewise.
	(bpstat_check_watchpoint): Likewise.
	(set_longjmp_breakpoint): Likewise.
	(struct fork_catchpoint): Inherit from breakpoint.
	<base>: Remove.
	(struct solib_catchpoint): Inherit from breakpoint.
	<~solib_catchpoint>: New.
	<base>: Remove.
	(dtor_catch_solib): Change to ...
	(solib_catchpoint::~solib_catchpoint): ... this.
	(breakpoint_hit_catch_solib): Remove reference to base field.
	(add_solib_catchpoint): Likewise.
	(create_fork_vfork_event_catchpoint): Likewise.
	(struct exec_catchpoint): Inherit from breakpoint.
	<~exec_catchpoint>: New.
	<base>: Remove.
	(dtor_catch_exec): Change to ...
	(exec_catchpoint::~exec_catchpoint): ... this.
	(dtor_watchpoint): Change to ...
	(watchpoint::~watchpoint): ... this.
	(watch_command_1): Remove reference to base field.
	(catch_exec_command_1): Likewise.
	(base_breakpoint_dtor): Change to ...
	(breakpoint::~breakpoint): ... this.
	(base_breakpoint_ops): Remove dtor field value.
	(longjmp_bkpt_dtor): Change to ...
	(longjmp_breakpoint::~longjmp_breakpoint): ... this.
	(strace_marker_create_breakpoints_sal): Remove reference to base
	field.
	(delete_breakpoint): Don't manually call breakpoint destructor.
	(create_tracepoint_from_upload): Remove reference to base field.
	(trace_pass_set_count): Likewise.
	(initialize_breakpoint_ops): Don't initialize
	momentary_breakpoint_ops, don't set dtors.
	* ada-lang.c (struct ada_catchpoint): Inherit from breakpoint.
	<~ada_catchpoint>: New.
	<base>: Remove.
	(create_excep_cond_exprs): Remove reference to base field.
	(dtor_exception): Change to ...
	(ada_catchpoint::~ada_catchpoint): ... this.
	(dtor_catch_exception): Remove.
	(dtor_catch_exception_unhandled): Remove.
	(dtor_catch_assert): Remove.
	(create_ada_exception_catchpoint): Remove reference to base
	field.
	(initialize_ada_catchpoint_ops): Don't set dtors.
	* break-catch-sig.c (struct signal_catchpoint): Inherit from
	breakpoint.
	<~signal_catchpoint>: New.
	<base>: Remove.
	(signal_catchpoint_dtor): Change to ...
	(signal_catchpoint::~signal_catchpoint): ... this.
	(create_signal_catchpoint): Remove reference to base field.
	(initialize_signal_catchpoint_ops): Don't set dtor.
	* break-catch-syscall.c (struct syscall_catchpoint): Inherit
	from breakpoint.
	<~syscall_catchpoint>: New.
	<base>: Remove.
	(dtor_catch_syscall): Change to ...
	(syscall_catchpoint::~syscall_catchpoint): ... this.
	(create_syscall_event_catchpoint): Remove reference to base
	field.
	(initialize_syscall_catchpoint_ops): Don't set dtor.
	* break-catch-throw.c (struct exception_catchpoint): Inherit
	from breakpoint.
	<~exception_catchpoint>: New.
	<base>: Remove.
	(dtor_exception_catchpoint): Change to ...
	(exception_catchpoint::~exception_catchpoint): ... this.
	(handle_gnu_v3_exceptions): Remove reference to base field.
	(initialize_throw_catchpoint_ops): Don't set dtor.
	* ctf.c (ctf_get_traceframe_address): Remove reference to base
	field.
	* remote.c (remote_get_tracepoint_status): Likewise.
	* tracefile-tfile.c (tfile_get_traceframe_address): Likewise.
	* tracefile.c (tracefile_fetch_registers): Likewise.
	* tracepoint.c (actions_command): Likewise.
	(validate_actionline): Likewise.
	(tfind_1): Likewise.
	(get_traceframe_location): Likewise.
	(find_matching_tracepoint_location): Likewise.
	(parse_tracepoint_status): Likewise.
	* mi/mi-cmd-break.c (mi_cmd_break_passcount): Likewise.

1 files changed, 8 insertions, 18 deletions

diff --git a/gdb/break-catch-syscall.c b/gdb/break-catch-syscall.c
index 322f680..92ab91b 100644
--- a/gdb/break-catch-syscall.c
+++ b/gdb/break-catch-syscall.c
@@ -31,15 +31,12 @@
 #include "xml-syscall.h"
 
 /* An instance of this type is used to represent a syscall catchpoint.
-   It includes a "struct breakpoint" as a kind of base class; users
-   downcast to "struct breakpoint *" when needed.  A breakpoint is
-   really of this type iff its ops pointer points to
+   A breakpoint is really of this type iff its ops pointer points to
    CATCH_SYSCALL_BREAKPOINT_OPS.  */
 
-struct syscall_catchpoint
+struct syscall_catchpoint : public breakpoint
 {
-  /* The base class.  */
-  struct breakpoint base;
+  ~syscall_catchpoint () override;
 
   /* Syscall numbers used for the 'catch syscall' feature.  If no
      syscall has been specified for filtering, its value is NULL.
@@ -48,17 +45,11 @@ struct syscall_catchpoint
   VEC(int) *syscalls_to_be_caught;
 };
 
-/* Implement the "dtor" breakpoint_ops method for syscall
-   catchpoints.  */
+/* catch_syscall destructor.  */
 
-static void
-dtor_catch_syscall (struct breakpoint *b)
+syscall_catchpoint::~syscall_catchpoint ()
 {
-  struct syscall_catchpoint *c = (struct syscall_catchpoint *) b;
-
-  VEC_free (int, c->syscalls_to_be_caught);
-
-  base_breakpoint_ops.dtor (b);
+  VEC_free (int, this->syscalls_to_be_caught);
 }
 
 static const struct inferior_data *catch_syscall_inferior_data = NULL;
@@ -434,10 +425,10 @@ create_syscall_event_catchpoint (int tempflag, VEC(int) *filter,
   struct gdbarch *gdbarch = get_current_arch ();
 
   c = new syscall_catchpoint ();
-  init_catchpoint (&c->base, gdbarch, tempflag, NULL, ops);
+  init_catchpoint (c, gdbarch, tempflag, NULL, ops);
   c->syscalls_to_be_caught = filter;
 
-  install_breakpoint (0, &c->base, 1);
+  install_breakpoint (0, c, 1);
 }
 
 /* Splits the argument using space as delimiter.  Returns an xmalloc'd
@@ -701,7 +692,6 @@ initialize_syscall_catchpoint_ops (void)
   /* Syscall catchpoints.  */
   ops = &catch_syscall_breakpoint_ops;
   *ops = base_breakpoint_ops;
-  ops->dtor = dtor_catch_syscall;
   ops->insert_location = insert_catch_syscall;
   ops->remove_location = remove_catch_syscall;
   ops->breakpoint_hit = breakpoint_hit_catch_syscall;