[RFA v2 16/17] Add a constructor and destructor to linespec_result

[Tom Tromey <tom at tromey dot com>]

linespec_result is only ever allocated on the stack, so it's
relatively easy to convert to having a constructor and a destructor.
This patch makes this change.  This removes some cleanups.

2017-04-11  Tom Tromey  <tom@tromey.com>

	* linespec.h (struct linespec_result): Add constructor and
	destructor.
	(init_linespec_result, destroy_linespec_result)
	(make_cleanup_destroy_linespec_result): Don't declare.
	* linespec.c (init_linespec_result): Remove.
	(linespec_result::~linespec_result): Rename from
	destroy_linespec_result.  Update.
	(cleanup_linespec_result, make_cleanup_destroy_linespec_result):
	Remove.
	* breakpoint.c (create_breakpoint, break_range_command)
	(decode_location_default): Update.
	* ax-gdb.c (agent_command_1): Update.
---
 gdb/ChangeLog    | 15 +++++++++++++++
 gdb/ax-gdb.c     |  5 +----
 gdb/breakpoint.c | 19 +------------------
 gdb/linespec.c   | 35 ++++-------------------------------
 gdb/linespec.h   | 30 ++++++++++++++----------------
 5 files changed, 35 insertions(+), 69 deletions(-)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 3faadc2..fc600b1 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,20 @@
 2017-04-11  Tom Tromey  <tom@tromey.com>
 
+	* linespec.h (struct linespec_result): Add constructor and
+	destructor.
+	(init_linespec_result, destroy_linespec_result)
+	(make_cleanup_destroy_linespec_result): Don't declare.
+	* linespec.c (init_linespec_result): Remove.
+	(linespec_result::~linespec_result): Rename from
+	destroy_linespec_result.  Update.
+	(cleanup_linespec_result, make_cleanup_destroy_linespec_result):
+	Remove.
+	* breakpoint.c (create_breakpoint, break_range_command)
+	(decode_location_default): Update.
+	* ax-gdb.c (agent_command_1): Update.
+
+2017-04-11  Tom Tromey  <tom@tromey.com>
+
 	* remote.c (remote_download_tracepoint): Update.
 	* python/py-breakpoint.c (bppy_get_location): Update.
 	* guile/scm-breakpoint.c (bpscm_print_breakpoint_smob)
diff --git a/gdb/ax-gdb.c b/gdb/ax-gdb.c
index 7206022..fae2e2d 100644
--- a/gdb/ax-gdb.c
+++ b/gdb/ax-gdb.c
@@ -2603,15 +2603,13 @@ agent_command_1 (char *exp, int eval)
       struct linespec_result canonical;
       int ix;
       struct linespec_sals *iter;
-      struct cleanup *old_chain;
 
       exp = skip_spaces (exp);
-      init_linespec_result (&canonical);
+
       event_location_up location = new_linespec_location (&exp);
       decode_line_full (location.get (), DECODE_LINE_FUNFIRSTLINE, NULL,
 			(struct symtab *) NULL, 0, &canonical,
 			NULL, NULL);
-      old_chain = make_cleanup_destroy_linespec_result (&canonical);
       exp = skip_spaces (exp);
       if (exp[0] == ',')
         {
@@ -2625,7 +2623,6 @@ agent_command_1 (char *exp, int eval)
 	  for (i = 0; i < iter->sals.nelts; i++)
 	    agent_eval_command_one (exp, eval, iter->sals.sals[i].pc);
         }
-      do_cleanups (old_chain);
     }
   else
     agent_eval_command_one (exp, eval, get_frame_pc (get_current_frame ()));
diff --git a/gdb/breakpoint.c b/gdb/breakpoint.c
index afc8309..42f344a 100644
--- a/gdb/breakpoint.c
+++ b/gdb/breakpoint.c
@@ -9726,7 +9726,6 @@ create_breakpoint (struct gdbarch *gdbarch,
 		   unsigned flags)
 {
   struct linespec_result canonical;
-  struct cleanup *old_chain;
   struct cleanup *bkpt_chain = NULL;
   int pending = 0;
   int task = 0;
@@ -9738,8 +9737,6 @@ create_breakpoint (struct gdbarch *gdbarch,
   if (extra_string != NULL && *extra_string == '\0')
     extra_string = NULL;
 
-  init_linespec_result (&canonical);
-
   TRY
     {
       ops->create_sals_from_location (location, &canonical, type_wanted);
@@ -9779,9 +9776,6 @@ create_breakpoint (struct gdbarch *gdbarch,
   if (!pending && VEC_empty (linespec_sals, canonical.sals))
     return 0;
 
-  /* Create a chain of things that always need to be cleaned up.  */
-  old_chain = make_cleanup_destroy_linespec_result (&canonical);
-
   /* ----------------------------- SNIP -----------------------------
      Anything added to the cleanup chain beyond this point is assumed
      to be part of a breakpoint.  If the breakpoint create succeeds
@@ -9922,8 +9916,6 @@ create_breakpoint (struct gdbarch *gdbarch,
   /* That's it.  Discard the cleanups for data inserted into the
      breakpoint.  */
   discard_cleanups (bkpt_chain);
-  /* But cleanup everything else.  */
-  do_cleanups (old_chain);
 
   /* error call may happen here - have BKPT_CHAIN already discarded.  */
   update_global_location_list (UGLL_MAY_INSERT);
@@ -10372,13 +10364,10 @@ break_range_command (char *arg, int from_tty)
   if (arg == NULL || arg[0] == '\0')
     error(_("No address range specified."));
 
-  init_linespec_result (&canonical_start);
-
   arg_start = arg;
   event_location_up start_location = string_to_event_location (&arg,
 							       current_language);
   parse_breakpoint_sals (start_location.get (), &canonical_start);
-  cleanup_bkpt = make_cleanup_destroy_linespec_result (&canonical_start);
 
   if (arg[0] != ',')
     error (_("Too few arguments."));
@@ -10393,14 +10382,13 @@ break_range_command (char *arg, int from_tty)
 
   sal_start = lsal_start->sals.sals[0];
   addr_string_start = savestring (arg_start, arg - arg_start);
-  make_cleanup (xfree, addr_string_start);
+  cleanup_bkpt = make_cleanup (xfree, addr_string_start);
 
   arg++;	/* Skip the comma.  */
   arg = skip_spaces (arg);
 
   /* Parse the end location.  */
 
-  init_linespec_result (&canonical_end);
   arg_start = arg;
 
   /* We call decode_line_full directly here instead of using
@@ -10414,8 +10402,6 @@ break_range_command (char *arg, int from_tty)
 		    sal_start.symtab, sal_start.line,
 		    &canonical_end, NULL, NULL);
 
-  make_cleanup_destroy_linespec_result (&canonical_end);
-
   if (VEC_empty (linespec_sals, canonical_end.sals))
     error (_("Could not find location of the end of the range."));
 
@@ -14487,7 +14473,6 @@ decode_location_default (struct breakpoint *b,
 {
   struct linespec_result canonical;
 
-  init_linespec_result (&canonical);
   decode_line_full (location, DECODE_LINE_FUNFIRSTLINE, search_pspace,
 		    (struct symtab *) NULL, 0,
 		    &canonical, multiple_symbols_all,
@@ -14506,8 +14491,6 @@ decode_location_default (struct breakpoint *b,
 	 contents.  */
       lsal->sals.sals = NULL;
     }
-
-  destroy_linespec_result (&canonical);
 }
 
 /* Prepare the global context for a re-set of breakpoint B.  */
diff --git a/gdb/linespec.c b/gdb/linespec.c
index bccabaf..51fa128 100644
--- a/gdb/linespec.c
+++ b/gdb/linespec.c
@@ -3887,45 +3887,18 @@ symbol_to_sal (struct symtab_and_line *result,
   return 0;
 }
 
-/* See the comment in linespec.h.  */
-
-void
-init_linespec_result (struct linespec_result *lr)
-{
-  memset (lr, 0, sizeof (*lr));
-}
-
-/* See the comment in linespec.h.  */
-
-void
-destroy_linespec_result (struct linespec_result *ls)
+linespec_result::~linespec_result ()
 {
   int i;
   struct linespec_sals *lsal;
 
-  delete_event_location (ls->location);
-  for (i = 0; VEC_iterate (linespec_sals, ls->sals, i, lsal); ++i)
+  delete_event_location (location);
+  for (i = 0; VEC_iterate (linespec_sals, sals, i, lsal); ++i)
     {
       xfree (lsal->canonical);
       xfree (lsal->sals.sals);
     }
-  VEC_free (linespec_sals, ls->sals);
-}
-
-/* Cleanup function for a linespec_result.  */
-
-static void
-cleanup_linespec_result (void *a)
-{
-  destroy_linespec_result ((struct linespec_result *) a);
-}
-
-/* See the comment in linespec.h.  */
-
-struct cleanup *
-make_cleanup_destroy_linespec_result (struct linespec_result *ls)
-{
-  return make_cleanup (cleanup_linespec_result, ls);
+  VEC_free (linespec_sals, sals);
 }
 
 /* Return the quote characters permitted by the linespec parser.  */
diff --git a/gdb/linespec.h b/gdb/linespec.h
index 4e69895..7459ff8 100644
--- a/gdb/linespec.h
+++ b/gdb/linespec.h
@@ -54,12 +54,23 @@ typedef struct linespec_sals linespec_sals;
 DEF_VEC_O (linespec_sals);
 
 /* An instance of this may be filled in by decode_line_1.  The caller
-   must call init_linespec_result to initialize it and
-   destroy_linespec_result to destroy it.  The caller must make copies
-   of any data that it needs to keep.  */
+   must make copies of any data that it needs to keep.  */
 
 struct linespec_result
 {
+  linespec_result ()
+    : special_display (0),
+      pre_expanded (0),
+      location (NULL),
+      sals (NULL)
+  {
+  }
+
+  ~linespec_result ();
+
+  linespec_result (const linespec_result &) = delete;
+  linespec_result &operator= (const linespec_result &) = delete;
+
   /* If non-zero, the linespec should be displayed to the user.  This
      is used by "unusual" linespecs where the ordinary `info break'
      display mechanism would do the wrong thing.  */
@@ -80,19 +91,6 @@ struct linespec_result
   VEC (linespec_sals) *sals;
 };
 
-/* Initialize a linespec_result.  */
-
-extern void init_linespec_result (struct linespec_result *);
-
-/* Destroy a linespec_result.  */
-
-extern void destroy_linespec_result (struct linespec_result *);
-
-/* Return a cleanup that destroys a linespec_result.  */
-
-extern struct cleanup *
-        make_cleanup_destroy_linespec_result (struct linespec_result *);
-
 /* Decode a linespec using the provided default symtab and line.  */
 
 extern struct symtabs_and_lines
-- 
2.9.3