-Wwrite-strings: Constify word break character arrays

-Wwrite-strings flags several cases of missing casts around
initializations like:

   static char *gdb_completer_command_word_break_characters =
    " \t\n!@#$%^&*()+=|~`}{[]\"';:?/>.<,";

Obviously these could/should be const.  However, while at it, there's
no need for these variables to be pointers instead of arrays.  They
are never changed to point to anything else.

Unfortunately, readline's rl_completer_word_break_characters is
"char *", not "const char *".  So we always need a cast somewhere.  The
approach taken here is to add a new
set_rl_completer_word_break_characters function that becomes the only
place that writes to rl_completer_word_break_characters, and thus the
single place that needs the cast.

gdb/ChangeLog:
2017-04-05  Pedro Alves  <palves@redhat.com>

	* ada-lang.c (ada_completer_word_break_characters): Now a const
	array.
	(ada_get_gdb_completer_word_break_characters): Constify.
	* completer.c (gdb_completer_command_word_break_characters)
	(gdb_completer_file_name_break_characters)
	(gdb_completer_quote_characters): Now const arrays.
	(get_gdb_completer_quote_characters): Constify.
	(set_rl_completer_word_break_characters): New function.
	(set_gdb_completion_word_break_characters)
	(complete_line_internal): Use it.
	* completer.h (get_gdb_completer_quote_characters): Constify.
	(set_rl_completer_word_break_characters): Declare.
	* f-lang.c (f_word_break_characters): Constify.
	* language.c (default_word_break_characters): Constify.
	* language.h (language_defn::la_word_break_characters): Constify.
	(default_word_break_characters): Constify.
	* top.c (init_main): Use set_rl_completer_word_break_characters.

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index f0219682c50d1afa7d0f67085b3a4ac6e2415d45..bc9fa4f6fa2b409692b12f027f82c46e70e06ca6 100644 (file)
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,23 @@
+2017-04-05  Pedro Alves  <palves@redhat.com>
+
+       * ada-lang.c (ada_completer_word_break_characters): Now a const
+       array.
+       (ada_get_gdb_completer_word_break_characters): Constify.
+       * completer.c (gdb_completer_command_word_break_characters)
+       (gdb_completer_file_name_break_characters)
+       (gdb_completer_quote_characters): Now const arrays.
+       (get_gdb_completer_quote_characters): Constify.
+       (set_rl_completer_word_break_characters): New function.
+       (set_gdb_completion_word_break_characters)
+       (complete_line_internal): Use it.
+       * completer.h (get_gdb_completer_quote_characters): Constify.
+       (set_rl_completer_word_break_characters): Declare.
+       * f-lang.c (f_word_break_characters): Constify.
+       * language.c (default_word_break_characters): Constify.
+       * language.h (language_defn::la_word_break_characters): Constify.
+       (default_word_break_characters): Constify.
+       * top.c (init_main): Use set_rl_completer_word_break_characters.
+
 2017-04-05  Pedro Alves  <palves@redhat.com>
 
        * aix-thread.c (aix_thread_pid_to_str)

diff --git a/gdb/ada-lang.c b/gdb/ada-lang.c
index 9b91e0cc5c1e18097011193e8958946968538d2f..7be135edfc16e308358de1dbf3865e0edcc29bcf 100644 (file)
--- a/gdb/ada-lang.c
+++ b/gdb/ada-lang.c
@@ -315,9 +315,7 @@ static void ada_free_symbol_cache (struct ada_symbol_cache *sym_cache);
 /* Maximum-sized dynamic type.  */
 static unsigned int varsize_limit;
 
-/* FIXME: brobecker/2003-09-17: No longer a const because it is
-   returned by a function that does not return a const char *.  */
-static char *ada_completer_word_break_characters =
+static const char ada_completer_word_break_characters[] =
 #ifdef VMS
   " \t\n!@#%^&*()+=|~`}{[]\";:?/,-";
 #else
@@ -558,7 +556,7 @@ add_angle_brackets (const char *str)
   return result;
 }
 
-static char *
+static const char *
 ada_get_gdb_completer_word_break_characters (void)
 {
   return ada_completer_word_break_characters;

diff --git a/gdb/completer.c b/gdb/completer.c
index 45adc627dc44419647e35e3d07e410948fafb0a2..9183e2aef7a75144662720d164ec2dc9a3fe7ed0 100644 (file)
--- a/gdb/completer.c
+++ b/gdb/completer.c
@@ -84,29 +84,30 @@ char *line_completion_function (const char *text, int matches,
    readline library sees one in any of the current completion strings,
    it thinks that the string needs to be quoted and automatically
    supplies a leading quote.  */
-static char *gdb_completer_command_word_break_characters =
+static const char gdb_completer_command_word_break_characters[] =
 " \t\n!@#$%^&*()+=|~`}{[]\"';:?/>.<,";
 
 /* When completing on file names, we remove from the list of word
    break characters any characters that are commonly used in file
    names, such as '-', '+', '~', etc.  Otherwise, readline displays
    incorrect completion candidates.  */
-#ifdef HAVE_DOS_BASED_FILE_SYSTEM
 /* MS-DOS and MS-Windows use colon as part of the drive spec, and most
    programs support @foo style response files.  */
-static char *gdb_completer_file_name_break_characters = " \t\n*|\"';?><@";
+static const char gdb_completer_file_name_break_characters[] =
+#ifdef HAVE_DOS_BASED_FILE_SYSTEM
+  " \t\n*|\"';?><@";
 #else
-static char *gdb_completer_file_name_break_characters = " \t\n*|\"';:?><";
+  " \t\n*|\"';:?><";
 #endif
 
 /* Characters that can be used to quote completion strings.  Note that
    we can't include '"' because the gdb C parser treats such quoted
    sequences as strings.  */
-static char *gdb_completer_quote_characters = "'";
+static const char gdb_completer_quote_characters[] = "'";
 \f
 /* Accessor for some completer data that may interest other files.  */
 
-char *
+const char *
 get_gdb_completer_quote_characters (void)
 {
   return gdb_completer_quote_characters;
@@ -651,17 +652,27 @@ expression_completer (struct cmd_list_element *ignore,
 
 /* See definition in completer.h.  */
 
+void
+set_rl_completer_word_break_characters (const char *break_chars)
+{
+  rl_completer_word_break_characters = (char *) break_chars;
+}
+
+/* See definition in completer.h.  */
+
 void
 set_gdb_completion_word_break_characters (completer_ftype *fn)
 {
+  const char *break_chars;
+
   /* So far we are only interested in differentiating filename
      completers from everything else.  */
   if (fn == filename_completer)
-    rl_completer_word_break_characters
-      = gdb_completer_file_name_break_characters;
+    break_chars = gdb_completer_file_name_break_characters;
   else
-    rl_completer_word_break_characters
-      = gdb_completer_command_word_break_characters;
+    break_chars = gdb_completer_command_word_break_characters;
+
+  set_rl_completer_word_break_characters (break_chars);
 }
 
 /* Here are some useful test cases for completion.  FIXME: These
@@ -743,8 +754,8 @@ complete_line_internal (const char *text,
      then we will switch to the special word break set for command
      strings, which leaves out the '-' character used in some
      commands.  */
-  rl_completer_word_break_characters =
-    current_language->la_word_break_characters();
+  set_rl_completer_word_break_characters
+    (current_language->la_word_break_characters());
 
   /* Decide whether to complete on a list of gdb commands or on
      symbols.  */
@@ -821,8 +832,8 @@ complete_line_internal (const char *text,
            }
          /* Ensure that readline does the right thing with respect to
             inserting quotes.  */
-         rl_completer_word_break_characters =
-           gdb_completer_command_word_break_characters;
+         set_rl_completer_word_break_characters
+           (gdb_completer_command_word_break_characters);
        }
     }
   else
@@ -848,8 +859,8 @@ complete_line_internal (const char *text,
 
                  /* Ensure that readline does the right thing
                     with respect to inserting quotes.  */
-                 rl_completer_word_break_characters =
-                   gdb_completer_command_word_break_characters;
+                 set_rl_completer_word_break_characters
+                   (gdb_completer_command_word_break_characters);
                }
              else if (reason == handle_help)
                list = NULL;
@@ -857,8 +868,8 @@ complete_line_internal (const char *text,
                {
                  if (reason != handle_brkchars)
                    list = complete_on_enum (c->enums, p, word);
-                 rl_completer_word_break_characters =
-                   gdb_completer_command_word_break_characters;
+                 set_rl_completer_word_break_characters
+                   (gdb_completer_command_word_break_characters);
                }
              else
                {
@@ -879,8 +890,8 @@ complete_line_internal (const char *text,
                             && strchr (gdb_completer_file_name_break_characters, p[-1]) == NULL;
                           p--)
                        ;
-                     rl_completer_word_break_characters =
-                       gdb_completer_file_name_break_characters;
+                     set_rl_completer_word_break_characters
+                       (gdb_completer_file_name_break_characters);
                    }
                  if (reason == handle_brkchars
                      && c->completer_handle_brkchars != NULL)
@@ -913,8 +924,8 @@ complete_line_internal (const char *text,
 
              /* Ensure that readline does the right thing
                 with respect to inserting quotes.  */
-             rl_completer_word_break_characters =
-               gdb_completer_command_word_break_characters;
+             set_rl_completer_word_break_characters
+               (gdb_completer_command_word_break_characters);
            }
        }
       else if (reason == handle_help)
@@ -947,8 +958,8 @@ complete_line_internal (const char *text,
                                    p[-1]) == NULL;
                       p--)
                    ;
-                 rl_completer_word_break_characters =
-                   gdb_completer_file_name_break_characters;
+                 set_rl_completer_word_break_characters
+                   (gdb_completer_file_name_break_characters);
                }
              if (reason == handle_brkchars
                  && c->completer_handle_brkchars != NULL)

diff --git a/gdb/completer.h b/gdb/completer.h
index 416b3134f52d403496b17a7c163f07b9dae01057..2aa1987f303e31313bac4f56a254fe7bfcd62a0d 100644 (file)
--- a/gdb/completer.h
+++ b/gdb/completer.h
@@ -99,10 +99,16 @@ extern VEC (char_ptr) *reg_or_group_completer (struct cmd_list_element *,
 extern VEC (char_ptr) *reggroup_completer (struct cmd_list_element *,
                                           const char *, const char *);
 
-extern char *get_gdb_completer_quote_characters (void);
+extern const char *get_gdb_completer_quote_characters (void);
 
 extern char *gdb_completion_word_break_characters (void);
 
+/* Set the word break characters array to BREAK_CHARS.  This function
+   is useful as const-correct alternative to direct assignment to
+   rl_completer_word_break_characters, which is "char *",
+   not "const char *".  */
+extern void set_rl_completer_word_break_characters (const char *break_chars);
+
 /* Set the word break characters array to the corresponding set of
    chars, based on FN.  This function is useful for cases when the
    completer doesn't know the type of the completion until some

diff --git a/gdb/f-lang.c b/gdb/f-lang.c
index 8aba5efe027dfd48b3cce469dc791ec7285873ba..3c30d75627c52bf106be73f62222b907d706913f 100644 (file)
--- a/gdb/f-lang.c
+++ b/gdb/f-lang.c
@@ -203,7 +203,7 @@ f_language_arch_info (struct gdbarch *gdbarch,
 
 /* Remove the modules separator :: from the default break list.  */
 
-static char *
+static const char *
 f_word_break_characters (void)
 {
   static char *retval;

diff --git a/gdb/language.c b/gdb/language.c
index 119c07ecb67599876a0d0463833c6bb114b20473..f1fc220ea8933be99cac7948415bb25668c10698 100644 (file)
--- a/gdb/language.c
+++ b/gdb/language.c
@@ -698,7 +698,7 @@ default_pass_by_reference (struct type *type)
    delimiting words.  This is a reasonable default value that
    most languages should be able to use.  */
 
-char *
+const char *
 default_word_break_characters (void)
 {
   return " \t\n!@#$%^&*()+=|~`}{[]\"';:?/>.<,-";

diff --git a/gdb/language.h b/gdb/language.h
index 3d21e4e388070d207c904ce1ea41b19f03994cba..96080ac4eca216605fecbd29dcc0fe7c17bbbb8b 100644 (file)
--- a/gdb/language.h
+++ b/gdb/language.h
@@ -321,7 +321,7 @@ struct language_defn
     char string_lower_bound;
 
     /* The list of characters forming word boundaries.  */
-    char *(*la_word_break_characters) (void);
+    const char *(*la_word_break_characters) (void);
 
     /* Should return a vector of all symbols which are possible
        completions for TEXT.  WORD is the entire command on which the
@@ -583,7 +583,7 @@ extern char *language_class_name_from_physname (const struct language_defn *,
                                                const char *physname);
 
 /* Splitting strings into words.  */
-extern char *default_word_break_characters (void);
+extern const char *default_word_break_characters (void);
 
 /* Print the index of an array element using the C99 syntax.  */
 extern void default_print_array_index (struct value *index_value,

diff --git a/gdb/top.c b/gdb/top.c
index 295b6806deff22a61a7ae7df7e0f5c3192e28ca0..4a22be135ab58caa28f19749c53c1dac5f96fb14 100644 (file)
--- a/gdb/top.c
+++ b/gdb/top.c
@@ -2022,7 +2022,7 @@ init_main (void)
   /* Setup important stuff for command line editing.  */
   rl_completion_word_break_hook = gdb_completion_word_break_characters;
   rl_completion_entry_function = readline_line_completion_function;
-  rl_completer_word_break_characters = default_word_break_characters ();
+  set_rl_completer_word_break_characters (default_word_break_characters ());
   rl_completer_quote_characters = get_gdb_completer_quote_characters ();
   rl_completion_display_matches_hook = cli_display_match_list;
   rl_readline_name = "gdb";