[1/3] RFC: introduce struct linespec_result

[Tom Tromey <tromey at redhat dot com>]

I needed to pass a new result from decode_line_1 back to the breakpoint
code.  At first I stuffed this into symtab_and_line, but I think it is
cleaner to add a new structure that is filled in by decode_line_1.
(This will also come in handy for the SystemTap probe work.)

This patch introduces struct linespec_result and updates everything to
use it.  It does not introduce any behavior changes.

Built and regtested on x86-64 (compile farm).

Tom

2011-03-18  Tom Tromey  <tromey@redhat.com>

	* symtab.c (decode_line_spec): Update.
	* linespec.c (build_canonical_line_spec): Change type of
	'canonical'.
	(decode_line_2, decode_line_1, decode_objc, decode_compound)
	(find_method, decode_all_digits, decode_dollar, decode_label)
	(symbol_found): Likewise.
	(init_linespec_result): New function.
	* breakpoint.c (struct captured_parse_breakpoint_args)
	<canonical_p>: New field, replaces addr_string_p.
	(create_breakpoints_sal): Add 'canonical' parameter, replacing
	'addr_string'.
	(parse_breakpoint_sals): Likewise.
	(do_captured_parse_breakpoint): Update.
	(create_breakpoint): Use struct linespec_result.
	(until_break_command): Update.
	(breakpoint_re_set_one): Update.
	(decode_line_spec_1): Update.
	* linespec.h (struct linespec_result): New.
	(init_linespec_result): Declare.

diff --git a/gdb/breakpoint.c b/gdb/breakpoint.c
index c55e5c0..c1c7b5a 100644
--- a/gdb/breakpoint.c
+++ b/gdb/breakpoint.c
@@ -5954,7 +5954,7 @@ struct captured_parse_breakpoint_args
   {
     char **arg_p;
     struct symtabs_and_lines *sals_p;
-    char ***addr_string_p;
+    struct linespec_result *canonical_p;
     int *not_found_ptr;
   };
 
@@ -7479,7 +7479,8 @@ expand_line_sal_maybe (struct symtab_and_line sal)
 
 static void
 create_breakpoints_sal (struct gdbarch *gdbarch,
-			struct symtabs_and_lines sals, char **addr_string,
+			struct symtabs_and_lines sals,
+			struct linespec_result *canonical,
 			char *cond_string,
 			enum bptype type, enum bpdisp disposition,
 			int thread, int task, int ignore_count,
@@ -7493,7 +7494,7 @@ create_breakpoints_sal (struct gdbarch *gdbarch,
       struct symtabs_and_lines expanded = 
 	expand_line_sal_maybe (sals.sals[i]);
 
-      create_breakpoint_sal (gdbarch, expanded, addr_string[i],
+      create_breakpoint_sal (gdbarch, expanded, canonical->canonical[i],
 			     cond_string, type, disposition,
 			     thread, task, ignore_count, ops,
 			     from_tty, enabled, internal);
@@ -7511,12 +7512,11 @@ create_breakpoints_sal (struct gdbarch *gdbarch,
 static void
 parse_breakpoint_sals (char **address,
 		       struct symtabs_and_lines *sals,
-		       char ***addr_string,
+		       struct linespec_result *canonical,
 		       int *not_found_ptr)
 {
   char *addr_start = *address;
 
-  *addr_string = NULL;
   /* If no arg given, or if first arg is 'if ', use the default
      breakpoint.  */
   if ((*address) == NULL
@@ -7565,15 +7565,15 @@ parse_breakpoint_sals (char **address,
  	      || ((strchr ("+-", (*address)[0]) != NULL)
  		  && ((*address)[1] != '['))))
 	*sals = decode_line_1 (address, 1, default_breakpoint_symtab,
-			       default_breakpoint_line, addr_string, 
+			       default_breakpoint_line, canonical, 
 			       not_found_ptr);
       else
 	*sals = decode_line_1 (address, 1, (struct symtab *) NULL, 0,
-		               addr_string, not_found_ptr);
+		               canonical, not_found_ptr);
     }
   /* For any SAL that didn't have a canonical string, fill one in.  */
-  if (sals->nelts > 0 && *addr_string == NULL)
-    *addr_string = xcalloc (sals->nelts, sizeof (char **));
+  if (sals->nelts > 0 && canonical->canonical == NULL)
+    canonical->canonical = xcalloc (sals->nelts, sizeof (char **));
   if (addr_start != (*address))
     {
       int i;
@@ -7581,9 +7581,9 @@ parse_breakpoint_sals (char **address,
       for (i = 0; i < sals->nelts; i++)
 	{
 	  /* Add the string if not present.  */
-	  if ((*addr_string)[i] == NULL)
-	    (*addr_string)[i] = savestring (addr_start, 
-					    (*address) - addr_start);
+	  if (canonical->canonical[i] == NULL)
+	    canonical->canonical[i] = savestring (addr_start, 
+						  (*address) - addr_start);
 	}
     }
 }
@@ -7638,7 +7638,7 @@ do_captured_parse_breakpoint (struct ui_out *ui, void *data)
 {
   struct captured_parse_breakpoint_args *args = data;
   
-  parse_breakpoint_sals (args->arg_p, args->sals_p, args->addr_string_p, 
+  parse_breakpoint_sals (args->arg_p, args->sals_p, args->canonical_p, 
 		         args->not_found_ptr);
 }
 
@@ -7782,7 +7782,7 @@ create_breakpoint (struct gdbarch *gdbarch,
   struct symtab_and_line pending_sal;
   char *copy_arg;
   char *addr_start = arg;
-  char **addr_string;
+  struct linespec_result canonical;
   struct cleanup *old_chain;
   struct cleanup *bkpt_chain = NULL;
   struct captured_parse_breakpoint_args parse_args;
@@ -7794,11 +7794,11 @@ create_breakpoint (struct gdbarch *gdbarch,
 
   sals.sals = NULL;
   sals.nelts = 0;
-  addr_string = NULL;
+  init_linespec_result (&canonical);
 
   parse_args.arg_p = &arg;
   parse_args.sals_p = &sals;
-  parse_args.addr_string_p = &addr_string;
+  parse_args.canonical_p = &canonical;
   parse_args.not_found_ptr = &not_found;
 
   if (type_wanted == bp_static_tracepoint && is_marker_spec (arg))
@@ -7808,9 +7808,9 @@ create_breakpoint (struct gdbarch *gdbarch,
       sals = decode_static_tracepoint_spec (&arg);
 
       copy_arg = savestring (addr_start, arg - addr_start);
-      addr_string = xcalloc (sals.nelts, sizeof (char **));
+      canonical.canonical = xcalloc (sals.nelts, sizeof (char **));
       for (i = 0; i < sals.nelts; i++)
-	addr_string[i] = xstrdup (copy_arg);
+	canonical.canonical[i] = xstrdup (copy_arg);
       goto done;
     }
 
@@ -7847,7 +7847,7 @@ create_breakpoint (struct gdbarch *gdbarch,
 	     breakpoint behavior is on and thus a pending breakpoint
 	     is defaulted on behalf of the user.  */
 	  copy_arg = xstrdup (addr_start);
-	  addr_string = &copy_arg;
+	  canonical.canonical = &copy_arg;
 	  sals.nelts = 1;
 	  sals.sals = &pending_sal;
 	  pending_sal.pc = 0;
@@ -7872,8 +7872,8 @@ create_breakpoint (struct gdbarch *gdbarch,
       /* Make sure that all storage allocated to SALS gets freed.  */
       make_cleanup (xfree, sals.sals);
       
-      /* Cleanup the addr_string array but not its contents.  */
-      make_cleanup (xfree, addr_string);
+      /* Cleanup the canonical array but not its contents.  */
+      make_cleanup (xfree, canonical.canonical);
     }
 
   /* ----------------------------- SNIP -----------------------------
@@ -7882,12 +7882,12 @@ create_breakpoint (struct gdbarch *gdbarch,
      then the memory is not reclaimed.  */
   bkpt_chain = make_cleanup (null_cleanup, 0);
 
-  /* Mark the contents of the addr_string for cleanup.  These go on
+  /* Mark the contents of the canonical for cleanup.  These go on
      the bkpt_chain and only occur if the breakpoint create fails.  */
   for (i = 0; i < sals.nelts; i++)
     {
-      if (addr_string[i] != NULL)
-	make_cleanup (xfree, addr_string[i]);
+      if (canonical.canonical[i] != NULL)
+	make_cleanup (xfree, canonical.canonical[i]);
     }
 
   /* Resolve all line numbers to PC's and verify that the addresses
@@ -7934,7 +7934,7 @@ create_breakpoint (struct gdbarch *gdbarch,
 	 expand multiple locations for each sal, given than SALS
 	 already should contain all sals for MARKER_ID.  */
       if (type_wanted == bp_static_tracepoint
-	  && is_marker_spec (addr_string[0]))
+	  && is_marker_spec (canonical.canonical[0]))
 	{
 	  int i;
 
@@ -7949,7 +7949,7 @@ create_breakpoint (struct gdbarch *gdbarch,
 	      expanded.sals[0] = sals.sals[i];
 	      old_chain = make_cleanup (xfree, expanded.sals);
 
-	      create_breakpoint_sal (gdbarch, expanded, addr_string[i],
+	      create_breakpoint_sal (gdbarch, expanded, canonical.canonical[i],
 				     cond_string, type_wanted,
 				     tempflag ? disp_del : disp_donttouch,
 				     thread, task, ignore_count, ops,
@@ -7974,7 +7974,7 @@ create_breakpoint (struct gdbarch *gdbarch,
 	    }
 	}
       else
-	create_breakpoints_sal (gdbarch, sals, addr_string, cond_string,
+	create_breakpoints_sal (gdbarch, sals, &canonical, cond_string,
 				type_wanted,
 				tempflag ? disp_del : disp_donttouch,
 				thread, task, ignore_count, ops, from_tty,
@@ -7989,7 +7989,7 @@ create_breakpoint (struct gdbarch *gdbarch,
       b = set_raw_breakpoint_without_location (gdbarch, type_wanted);
       set_breakpoint_number (internal, b);
       b->thread = -1;
-      b->addr_string = addr_string[0];
+      b->addr_string = canonical.canonical[0];
       b->cond_string = NULL;
       b->ignore_count = ignore_count;
       b->disposition = tempflag ? disp_del : disp_donttouch;
@@ -8857,10 +8857,9 @@ until_break_command (char *arg, int from_tty, int anywhere)
 
   if (default_breakpoint_valid)
     sals = decode_line_1 (&arg, 1, default_breakpoint_symtab,
-			  default_breakpoint_line, (char ***) NULL, NULL);
+			  default_breakpoint_line, NULL, NULL);
   else
-    sals = decode_line_1 (&arg, 1, (struct symtab *) NULL, 
-			  0, (char ***) NULL, NULL);
+    sals = decode_line_1 (&arg, 1, (struct symtab *) NULL, 0, NULL, NULL);
 
   if (sals.nelts != 1)
     error (_("Couldn't get information on specified line."));
@@ -10543,7 +10542,7 @@ breakpoint_re_set_one (void *bint)
 	    }
 	  else
 	    sals = decode_line_1 (&s, 1, (struct symtab *) NULL, 0,
-				  (char ***) NULL, not_found_ptr);
+				  NULL, not_found_ptr);
 	}
       if (e.reason < 0)
 	{
@@ -11149,10 +11148,10 @@ decode_line_spec_1 (char *string, int funfirstline)
     sals = decode_line_1 (&string, funfirstline,
 			  default_breakpoint_symtab,
 			  default_breakpoint_line,
-			  (char ***) NULL, NULL);
+			  NULL, NULL);
   else
     sals = decode_line_1 (&string, funfirstline,
-			  (struct symtab *) NULL, 0, (char ***) NULL, NULL);
+			  (struct symtab *) NULL, 0, NULL, NULL);
   if (*string)
     error (_("Junk at end of line specification: %s"), string);
   return sals;
diff --git a/gdb/linespec.c b/gdb/linespec.c
index 3959402..6c0e7ed 100644
--- a/gdb/linespec.c
+++ b/gdb/linespec.c
@@ -60,12 +60,12 @@ static char *locate_first_half (char **argptr, int *is_quote_enclosed);
 static struct symtabs_and_lines decode_objc (char **argptr,
 					     int funfirstline,
 					     struct symtab *file_symtab,
-					     char ***canonical,
+					     struct linespec_result *canonical,
 					     char *saved_arg);
 
 static struct symtabs_and_lines decode_compound (char **argptr,
 						 int funfirstline,
-						 char ***canonical,
+						 struct linespec_result *canonical,
 						 char *saved_arg,
 						 char *p,
 						 int *not_found_ptr);
@@ -73,7 +73,7 @@ static struct symtabs_and_lines decode_compound (char **argptr,
 static struct symbol *lookup_prefix_sym (char **argptr, char *p);
 
 static struct symtabs_and_lines find_method (int funfirstline,
-					     char ***canonical,
+					     struct linespec_result *canonical,
 					     char *saved_arg,
 					     char *copy,
 					     struct type *t,
@@ -97,14 +97,15 @@ static int add_constructors (int method_counter, struct type *t,
 			     struct symbol **sym_arr);
 
 static void build_canonical_line_spec (struct symtab_and_line *,
-				       char *, char ***);
+				       char *, struct linespec_result *);
 
 static char *find_toplevel_char (char *s, char c);
 
 static int is_objc_method_format (const char *s);
 
 static struct symtabs_and_lines decode_line_2 (struct symbol *[],
-					       int, int, char ***);
+					       int, int,
+					       struct linespec_result *);
 
 static struct symtab *symtab_from_filename (char **argptr,
 					    char *p, int is_quote_enclosed,
@@ -114,28 +115,28 @@ static struct
 symtabs_and_lines decode_all_digits (char **argptr,
 				     struct symtab *default_symtab,
 				     int default_line,
-				     char ***canonical,
+				     struct linespec_result *canonical,
 				     struct symtab *file_symtab,
 				     char *q);
 
 static struct symtabs_and_lines decode_dollar (char *copy,
 					       int funfirstline,
 					       struct symtab *default_symtab,
-					       char ***canonical,
+					       struct linespec_result *canonical,
 					       struct symtab *file_symtab);
 
-static int decode_label (char *copy, char ***canonical,
+static int decode_label (char *copy, struct linespec_result *canonical,
 			 struct symtabs_and_lines *result);
 
 static struct symtabs_and_lines decode_variable (char *copy,
 						 int funfirstline,
-						 char ***canonical,
+						 struct linespec_result *canonical,
 						 struct symtab *file_symtab,
 						 int *not_found_ptr);
 
 static struct
 symtabs_and_lines symbol_found (int funfirstline,
-				char ***canonical,
+				struct linespec_result *canonical,
 				char *copy,
 				struct symbol *sym,
 				struct symtab *file_symtab);
@@ -405,7 +406,7 @@ add_constructors (int method_counter, struct type *t,
 
 static void
 build_canonical_line_spec (struct symtab_and_line *sal, char *symname,
-			   char ***canonical)
+			   struct linespec_result *canonical)
 {
   char **canonical_arr;
   char *canonical_name;
@@ -414,11 +415,11 @@ build_canonical_line_spec (struct symtab_and_line *sal, char *symname,
 
   if (s == (struct symtab *) NULL
       || s->filename == (char *) NULL
-      || canonical == (char ***) NULL)
+      || canonical == NULL)
     return;
 
   canonical_arr = (char **) xmalloc (sizeof (char *));
-  *canonical = canonical_arr;
+  canonical->canonical = canonical_arr;
 
   filename = s->filename;
   if (symname != NULL)
@@ -498,7 +499,7 @@ is_objc_method_format (const char *s)
 
 static struct symtabs_and_lines
 decode_line_2 (struct symbol *sym_arr[], int nelts, int funfirstline,
-	       char ***canonical)
+	       struct linespec_result *canonical)
 {
   struct symtabs_and_lines values, return_values;
   char *args, *arg1;
@@ -524,7 +525,7 @@ decode_line_2 (struct symbol *sym_arr[], int nelts, int funfirstline,
       canonical_arr = (char **) xmalloc (nelts * sizeof (char *));
       make_cleanup (xfree, canonical_arr);
       memset (canonical_arr, 0, nelts * sizeof (char *));
-      *canonical = canonical_arr;
+      canonical->canonical = canonical_arr;
     }
 
   i = 0;
@@ -791,7 +792,8 @@ keep_name_info (char *ptr)
 
 struct symtabs_and_lines
 decode_line_1 (char **argptr, int funfirstline, struct symtab *default_symtab,
-	       int default_line, char ***canonical, int *not_found_ptr)
+	       int default_line, struct linespec_result *canonical,
+	       int *not_found_ptr)
 {
   char *p;
   char *q;
@@ -1187,7 +1189,7 @@ locate_first_half (char **argptr, int *is_quote_enclosed)
 
 struct symtabs_and_lines
 decode_objc (char **argptr, int funfirstline, struct symtab *file_symtab,
-	     char ***canonical, char *saved_arg)
+	     struct linespec_result *canonical, char *saved_arg)
 {
   struct symtabs_and_lines values;
   struct symbol **sym_arr = NULL;
@@ -1293,7 +1295,8 @@ decode_objc (char **argptr, int funfirstline, struct symtab *file_symtab,
    pointing to "AAA::inA::fun" and P pointing to "::inA::fun".  */
 
 static struct symtabs_and_lines
-decode_compound (char **argptr, int funfirstline, char ***canonical,
+decode_compound (char **argptr, int funfirstline,
+		 struct linespec_result *canonical,
 		 char *the_real_saved_arg, char *p, int *not_found_ptr)
 {
   struct symtabs_and_lines values;
@@ -1652,7 +1655,8 @@ lookup_prefix_sym (char **argptr, char *p)
    symbol is SYM_CLASS.  */
 
 static struct symtabs_and_lines
-find_method (int funfirstline, char ***canonical, char *saved_arg,
+find_method (int funfirstline, struct linespec_result *canonical,
+	     char *saved_arg,
 	     char *copy, struct type *t, struct symbol *sym_class,
 	     int *not_found_ptr)
 {
@@ -1815,7 +1819,7 @@ symtab_from_filename (char **argptr, char *p, int is_quote_enclosed,
 
 static struct symtabs_and_lines
 decode_all_digits (char **argptr, struct symtab *default_symtab,
-		   int default_line, char ***canonical,
+		   int default_line, struct linespec_result *canonical,
 		   struct symtab *file_symtab, char *q)
 
 {
@@ -1904,7 +1908,7 @@ decode_all_digits (char **argptr, struct symtab *default_symtab,
 
 static struct symtabs_and_lines
 decode_dollar (char *copy, int funfirstline, struct symtab *default_symtab,
-	       char ***canonical, struct symtab *file_symtab)
+	       struct linespec_result *canonical, struct symtab *file_symtab)
 {
   LONGEST valx;
   int index = 0;
@@ -1984,7 +1988,8 @@ decode_dollar (char *copy, int funfirstline, struct symtab *default_symtab,
    This function returns 1 if a label was found, 0 otherwise.  */
 
 static int
-decode_label (char *copy, char ***canonical, struct symtabs_and_lines *result)
+decode_label (char *copy, struct linespec_result *canonical,
+	      struct symtabs_and_lines *result)
 {
   struct symbol *sym;
 
@@ -2002,7 +2007,8 @@ decode_label (char *copy, char ***canonical, struct symtabs_and_lines *result)
    the location pointed to and do not issue an error message.  */ 
 
 static struct symtabs_and_lines
-decode_variable (char *copy, int funfirstline, char ***canonical,
+decode_variable (char *copy, int funfirstline,
+		 struct linespec_result *canonical,
 		 struct symtab *file_symtab, int *not_found_ptr)
 {
   struct symbol *sym;
@@ -2044,7 +2050,7 @@ decode_variable (char *copy, int funfirstline, char ***canonical,
    corresponding struct symtabs_and_lines.  */
 
 static struct symtabs_and_lines
-symbol_found (int funfirstline, char ***canonical, char *copy,
+symbol_found (int funfirstline, struct linespec_result *canonical, char *copy,
 	      struct symbol *sym, struct symtab *file_symtab)
 {
   struct symtabs_and_lines values;
@@ -2130,3 +2136,9 @@ minsym_found (int funfirstline, struct minimal_symbol *msymbol)
   values.nelts = 1;
   return values;
 }
+
+void
+init_linespec_result (struct linespec_result *lr)
+{
+  memset (lr, 0, sizeof (*lr));
+}
diff --git a/gdb/linespec.h b/gdb/linespec.h
index 7201638..3366fc6 100644
--- a/gdb/linespec.h
+++ b/gdb/linespec.h
@@ -20,9 +20,27 @@
 
 struct symtab;
 
+/* An instance of this may be filled in by decode_line_1.  The caller
+   must call init_linespec_result to initialize it.  */
+
+struct linespec_result
+{
+  /* If non-NULL, an array of canonical names for returned
+     symtab_and_line objects.  The array has as many elements as the
+     `nelts' field in the symtabs_and_line returned by decode_line_1.
+     An element in the array may be NULL.  The array and each non-NULL
+     element in it are allocated with xmalloc and must be freed by the
+     caller.  */
+  char **canonical;
+};
+
+/* Initialize a linespec_result.  */
+
+extern void init_linespec_result (struct linespec_result *);
+
 extern struct symtabs_and_lines
 	decode_line_1 (char **argptr, int funfirstline,
 		       struct symtab *default_symtab, int default_line,
-		       char ***canonical, int *not_found_ptr);
+		       struct linespec_result *canonical, int *not_found_ptr);
 
 #endif /* defined (LINESPEC_H) */
diff --git a/gdb/symtab.c b/gdb/symtab.c
index 60bc585..6882262 100644
--- a/gdb/symtab.c
+++ b/gdb/symtab.c
@@ -4401,7 +4401,7 @@ decode_line_spec (char *string, int funfirstline)
 
   sals = decode_line_1 (&string, funfirstline,
 			cursal.symtab, cursal.line,
-			(char ***) NULL, NULL);
+			NULL, NULL);
 
   if (*string)
     error (_("Junk at end of line specification: %s"), string);