Add max-completions parameter, and implement tab-completion limiting.

This commit adds a new exception, MAX_COMPLETIONS_REACHED_ERROR, to be thrown whenever the completer has generated too many candidates to be useful. A new user-settable variable, "max_completions", is added to control this behaviour. A top-level completion limit is added to complete_line_internal, as the final check to ensure the user never sees too many completions. An additional limit is added to default_make_symbol_completion_list_break_on, to halt time-consuming symbol table expansions. gdb/ChangeLog: PR cli/9007 PR cli/11920 PR cli/15548 * cli/cli-cmds.c (complete_command): Notify user if max-completions reached. * common/common-exceptions.h (enum errors) <MAX_COMPLETIONS_REACHED_ERROR>: New value. * completer.h (get_max_completions_reached_message): New declaration. (max_completions): Likewise. (completion_tracker_t): New typedef. (new_completion_tracker): New declaration. (make_cleanup_free_completion_tracker): Likewise. (maybe_add_completion_enum): New enum. (maybe_add_completion): New declaration. (throw_max_completions_reached_error): Likewise. * completer.c (max_completions): New global variable. (new_completion_tracker): New function. (free_completion_tracker): Likewise. (make_cleanup_free_completion_tracker): Likewise. (maybe_add_completions): Likewise. (throw_max_completions_reached_error): Likewise. (complete_line): Remove duplicates and limit result to max_completions entries. (get_max_completions_reached_message): New function. (gdb_display_match_list): Handle max_completions. (_initialize_completer): New declaration and function. * symtab.c: Include completer.h. (completion_tracker): New static variable. (completion_list_add_name): Call maybe_add_completion. (default_make_symbol_completion_list_break_on_1): Renamed from default_make_symbol_completion_list_break_on. Maintain completion_tracker across calls to completion_list_add_name. (default_make_symbol_completion_list_break_on): New function. * top.c (init_main): Set rl_completion_display_matches_hook. * tui/tui-io.c: Include completer.h. (tui_old_rl_display_matches_hook): New static global. (tui_rl_display_match_list): Notify user if max-completions reached. (tui_setup_io): Save/restore rl_completion_display_matches_hook. * NEWS (New Options): Mention set/show max-completions. gdb/doc/ChangeLog: * gdb.texinfo (Command Completion): Document new "set/show max-completions" option. gdb/testsuite/ChangeLog: * gdb.base/completion.exp: Disable completion limiting for existing tests. Add new tests to check completion limiting. * gdb.linespec/ls-errs.exp: Disable completion limiting.
2025-02-17 13:10:12 +08:00 · 2015-01-31 15:07:22 -08:00 · 2015-01-31 15:07:22 -08:00 · ef0b411a11
commit ef0b411a11
parent e11c72c7e4
10 changed files with 478 additions and 24 deletions
--- a/gdb/NEWS
+++ b/gdb/NEWS
@ -26,6 +26,13 @@ maint flush-symbol-cache

 * New options

+set max-completions
+show max-completions
+  Set the maximum number of candidates to be considered during
+  completion.  The default value is 200.  This limit allows GDB
+  to avoid generating large completion lists, the computation of
+  which can cause the debugger to become temporarily unresponsive.
+
 maint set symbol-cache-size
 maint show symbol-cache-size
  Control the size of the symbol cache.
--- a/gdb/cli/cli-cmds.c
+++ b/gdb/cli/cli-cmds.c
@ -236,7 +236,8 @@ help_command (char *command, int from_tty)
  help_cmd (command, gdb_stdout);
 }

-/* The "complete" command is used by Emacs to implement completion.  */
+/* Note: The "complete" command is used by Emacs to implement completion.
+   [Is that why this function writes output with *_unfiltered?]  */

 static void
 complete_command (char *arg, int from_tty)
@ -247,6 +248,18 @@ complete_command (char *arg, int from_tty)

  dont_repeat ();

+  if (max_completions == 0)
+    {
+      /* Only print this for non-mi frontends.  An MI frontend may not
+	 be able to handle this.  */
+      if (!ui_out_is_mi_like_p (current_uiout))
+	{
+	  printf_unfiltered (_("max-completions is zero,"
+			       " completion is disabled.\n"));
+	}
+      return;
+    }
+
  if (arg == NULL)
    arg = "";
  argpoint = strlen (arg);
@ -293,6 +306,15 @@ complete_command (char *arg, int from_tty)

      xfree (prev);
      VEC_free (char_ptr, completions);
+
+      if (size == max_completions)
+	{
+	  /* ARG_PREFIX and POINT are included in the output so that emacs
+	     will include the message in the output.  */
+	  printf_unfiltered (_("%s%s %s\n"),
+			     arg_prefix, point,
+			     get_max_completions_reached_message ());
+	}
    }
 }

--- a/gdb/common/common-exceptions.h
+++ b/gdb/common/common-exceptions.h
@ -99,6 +99,12 @@ enum errors {
  /* Requested feature, method, mechanism, etc. is not supported.  */
  NOT_SUPPORTED_ERROR,

+  /* The number of candidates generated during line completion has
+     reached the user's specified limit.  This isn't an error, this exception
+     is used to halt searching for more completions, but for consistency
+     "_ERROR" is appended to the name.  */
+  MAX_COMPLETIONS_REACHED_ERROR,
+
  /* Add more errors here.  */
  NR_ERRORS
 };
--- a/gdb/completer.c
+++ b/gdb/completer.c
@ -781,9 +781,93 @@ complete_line_internal (const char *text,

  return list;
 }
-/* Generate completions all at once.  Returns a vector of strings.
-   Each element is allocated with xmalloc.  It can also return NULL if
-   there are no completions.
+
+/* See completer.h.  */
+
+int max_completions = 200;
+
+/* See completer.h.  */
+
+completion_tracker_t
+new_completion_tracker (void)
+{
+  if (max_completions <= 0)
+    return NULL;
+
+  return htab_create_alloc (max_completions,
+			    htab_hash_string, (htab_eq) streq,
+			    NULL, xcalloc, xfree);
+}
+
+/* Cleanup routine to free a completion tracker and reset the pointer
+   to NULL.  */
+
+static void
+free_completion_tracker (void *p)
+{
+  completion_tracker_t *tracker_ptr = p;
+
+  htab_delete (*tracker_ptr);
+  *tracker_ptr = NULL;
+}
+
+/* See completer.h.  */
+
+struct cleanup *
+make_cleanup_free_completion_tracker (completion_tracker_t *tracker_ptr)
+{
+  if (*tracker_ptr == NULL)
+    return make_cleanup (null_cleanup, NULL);
+
+  return make_cleanup (free_completion_tracker, tracker_ptr);
+}
+
+/* See completer.h.  */
+
+enum maybe_add_completion_enum
+maybe_add_completion (completion_tracker_t tracker, char *name)
+{
+  void **slot;
+
+  if (max_completions < 0)
+    return MAYBE_ADD_COMPLETION_OK;
+  if (max_completions == 0)
+    return MAYBE_ADD_COMPLETION_MAX_REACHED;
+
+  gdb_assert (tracker != NULL);
+
+  if (htab_elements (tracker) >= max_completions)
+    return MAYBE_ADD_COMPLETION_MAX_REACHED;
+
+  slot = htab_find_slot (tracker, name, INSERT);
+
+  if (*slot != HTAB_EMPTY_ENTRY)
+    return MAYBE_ADD_COMPLETION_DUPLICATE;
+
+  *slot = name;
+
+  return (htab_elements (tracker) < max_completions
+	  ? MAYBE_ADD_COMPLETION_OK
+	  : MAYBE_ADD_COMPLETION_OK_MAX_REACHED);
+}
+
+void
+throw_max_completions_reached_error (void)
+{
+  throw_error (MAX_COMPLETIONS_REACHED_ERROR, _("Max completions reached."));
+}
+
+/* Generate completions all at once.  Returns a vector of unique strings
+   allocated with xmalloc.  Returns NULL if there are no completions
+   or if max_completions is 0.  If max_completions is non-negative, this will
+   return at most max_completions + 1 strings.
+
+   If max_completions strings are collected, an extra string is added which
+   is a text message to inform the user that the list may be truncated.
+   This extra string serves two purposes:
+   1) Inform the user.
+   2) Prevent readline from being able to find a common prefix to advance
+      point to, since it's working with an incomplete list.

   TEXT is the caller's idea of the "word" we are looking at.

@ -796,8 +880,58 @@ complete_line_internal (const char *text,
 VEC (char_ptr) *
 complete_line (const char *text, const char *line_buffer, int point)
 {
-  return complete_line_internal (text, line_buffer, 
-				 point, handle_completions);
+  VEC (char_ptr) *list;
+  VEC (char_ptr) *result = NULL;
+  struct cleanup *cleanups;
+  completion_tracker_t tracker;
+  char *candidate;
+  int ix, max_reached;
+
+  if (max_completions == 0)
+    return NULL;
+  list = complete_line_internal (text, line_buffer, point,
+				 handle_completions);
+  if (max_completions < 0)
+    return list;
+
+  tracker = new_completion_tracker ();
+  cleanups = make_cleanup_free_completion_tracker (&tracker);
+  make_cleanup_free_char_ptr_vec (list);
+
+  /* Do a final test for too many completions.  Individual completers may
+     do some of this, but are not required to.  Duplicates are also removed
+     here.  Otherwise the user is left scratching his/her head: readline and
+     complete_command will remove duplicates, and if removal of duplicates
+     there brings the total under max_completions the user may think gdb quit
+     searching too early.  */
+
+  for (ix = 0, max_reached = 0;
+       !max_reached && VEC_iterate (char_ptr, list, ix, candidate);
+       ++ix)
+    {
+      enum maybe_add_completion_enum add_status;
+
+      add_status = maybe_add_completion (tracker, candidate);
+
+      switch (add_status)
+	{
+	  case MAYBE_ADD_COMPLETION_OK:
+	    VEC_safe_push (char_ptr, result, xstrdup (candidate));
+	    break;
+	  case MAYBE_ADD_COMPLETION_OK_MAX_REACHED:
+	    VEC_safe_push (char_ptr, result, xstrdup (candidate));
+	    max_reached = 1;
+	    break;
+      	  case MAYBE_ADD_COMPLETION_MAX_REACHED:
+	    gdb_assert_not_reached ("more than max completions reached");
+	  case MAYBE_ADD_COMPLETION_DUPLICATE:
+	    break;
+	}
+    }
+
+  do_cleanups (cleanups);
+
+  return result;
 }

 /* Complete on command names.  Used by "help".  */
@ -1020,6 +1154,15 @@ skip_quoted (const char *str)
 {
  return skip_quoted_chars (str, NULL, NULL);
 }
+
+/* Return a message indicating that the maximum number of completions
+   has been reached and that there may be more.  */
+
+const char *
+get_max_completions_reached_message (void)
+{
+  return _("*** List may be truncated, max-completions reached. ***");
+}

 /* GDB replacement for rl_display_match_list.
   Readline doesn't provide a clean interface for TUI(curses).
@ -1413,9 +1556,10 @@ gdb_complete_get_screenwidth (const struct match_list_displayer *displayer)
 }

 /* GDB version of readline/complete.c:rl_display_match_list.
-   See gdb_display_match_list for a description of MATCHES, LEN, MAX.  */
+   See gdb_display_match_list for a description of MATCHES, LEN, MAX.
+   Returns non-zero if all matches are displayed.  */

-static void
+static int
 gdb_display_match_list_1 (char **matches, int len, int max,
 			  const struct match_list_displayer *displayer)
 {
@ -1501,7 +1645,7 @@ gdb_display_match_list_1 (char **matches, int len, int max,
 	    {
 	      lines = gdb_display_match_list_pager (lines, displayer);
 	      if (lines < 0)
-		return;
+		return 0;
 	    }
 	}
    }
@ -1523,7 +1667,7 @@ gdb_display_match_list_1 (char **matches, int len, int max,
 		    {
 		      lines = gdb_display_match_list_pager (lines, displayer);
 		      if (lines < 0)
-			return;
+			return 0;
 		    }
 		}
 	      else
@ -1533,6 +1677,8 @@ gdb_display_match_list_1 (char **matches, int len, int max,
 	}
      displayer->crlf (displayer);
    }
+
+  return 1;
 }

 /* Utility for displaying completion list matches, used by both CLI and TUI.
@ -1545,6 +1691,13 @@ void
 gdb_display_match_list (char **matches, int len, int max,
 			const struct match_list_displayer *displayer)
 {
+  /* Readline will never call this if complete_line returned NULL.  */
+  gdb_assert (max_completions != 0);
+
+  /* complete_line will never return more than this.  */
+  if (max_completions > 0)
+    gdb_assert (len <= max_completions);
+
  if (rl_completion_query_items > 0 && len >= rl_completion_query_items)
    {
      char msg[100];
@ -1567,5 +1720,33 @@ gdb_display_match_list (char **matches, int len, int max,
 	}
    }

-  gdb_display_match_list_1 (matches, len, max, displayer);
+  if (gdb_display_match_list_1 (matches, len, max, displayer))
+    {
+      /* Note: MAX_COMPLETIONS may be -1 or zero, but LEN is always > 0.  */
+      if (len == max_completions)
+	{
+	  /* The maximum number of completions has been reached.  Warn the user
+	     that there may be more.  */
+	  const char *message = get_max_completions_reached_message ();
+
+	  displayer->puts (displayer, message);
+	  displayer->crlf (displayer);
+	}
+    }
+}
+
+extern initialize_file_ftype _initialize_completer; /* -Wmissing-prototypes */
+
+void
+_initialize_completer (void)
+{
+  add_setshow_zuinteger_unlimited_cmd ("max-completions", no_class,
+				       &max_completions, _("\
+Set maximum number of completion candidates."), _("\
+Show maximum number of completion candidates."), _("\
+Use this to limit the number of candidates considered\n\
+during completion.  Specifying \"unlimited\" or -1\n\
+disables limiting.  Note that setting either no limit or\n\
+a very large limit can make completion slow."),
+				       NULL, NULL, &setlist, &showlist);
 }
--- a/gdb/completer.h
+++ b/gdb/completer.h
@ -66,6 +66,8 @@ struct match_list_displayer
 extern void gdb_display_match_list (char **matches, int len, int max,
 				    const struct match_list_displayer *);

+extern const char *get_max_completions_reached_message (void);
+
 extern VEC (char_ptr) *complete_line (const char *text,
 				      const char *line_buffer,
 				      int point);
@ -112,4 +114,68 @@ extern const char *skip_quoted_chars (const char *, const char *,

 extern const char *skip_quoted (const char *);

+/* Maximum number of candidates to consider before the completer
+   bails by throwing MAX_COMPLETIONS_REACHED_ERROR.  Negative values
+   disable limiting.  */
+
+extern int max_completions;
+
+/* Object to track how many unique completions have been generated.
+   Used to limit the size of generated completion lists.  */
+
+typedef htab_t completion_tracker_t;
+
+/* Create a new completion tracker.
+   The result is a hash table to track added completions, or NULL
+   if max_completions <= 0.  If max_completions < 0, tracking is disabled.
+   If max_completions == 0, the max is indeed zero.  */
+
+extern completion_tracker_t new_completion_tracker (void);
+
+/* Make a cleanup to free a completion tracker, and reset its pointer
+   to NULL.  */
+
+extern struct cleanup *make_cleanup_free_completion_tracker
+		      (completion_tracker_t *tracker_ptr);
+
+/* Return values for maybe_add_completion.  */
+
+enum maybe_add_completion_enum
+{
+  /* NAME has been recorded and max_completions has not been reached,
+     or completion tracking is disabled (max_completions < 0).  */
+  MAYBE_ADD_COMPLETION_OK,
+
+  /* NAME has been recorded and max_completions has been reached
+     (thus the caller can stop searching).  */
+  MAYBE_ADD_COMPLETION_OK_MAX_REACHED,
+
+  /* max-completions entries has been reached.
+     Whether NAME is a duplicate or not is not determined.  */
+  MAYBE_ADD_COMPLETION_MAX_REACHED,
+
+  /* NAME has already been recorded.
+     Note that this is never returned if completion tracking is disabled
+     (max_completions < 0).  */
+  MAYBE_ADD_COMPLETION_DUPLICATE
+};
+
+/* Add the completion NAME to the list of generated completions if
+   it is not there already.
+   If max_completions is negative, nothing is done, not even watching
+   for duplicates, and MAYBE_ADD_COMPLETION_OK is always returned.
+
+   If MAYBE_ADD_COMPLETION_MAX_REACHED is returned, callers are required to
+   record at least one more completion.  The final list will be pruned to
+   max_completions, but recording at least one more than max_completions is
+   the signal to the completion machinery that too many completions were
+   found.  */
+
+extern enum maybe_add_completion_enum
+  maybe_add_completion (completion_tracker_t tracker, char *name);
+
+/* Wrapper to throw MAX_COMPLETIONS_REACHED_ERROR.  */ 
+
+extern void throw_max_completions_reached_error (void);
+
 #endif /* defined (COMPLETER_H) */
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@ -1600,6 +1600,38 @@ means @kbd{@key{META} ?}.  You can type this either by holding down a
 key designated as the @key{META} shift on your keyboard (if there is
 one) while typing @kbd{?}, or as @key{ESC} followed by @kbd{?}.

+If the number of possible completions is large, @value{GDBN} will
+print as much of the list as it has collected, as well as a message
+indicating that the list may be truncated.
+
+@smallexample
+(@value{GDBP}) b m@key{TAB}@key{TAB}
+main
+<... the rest of the possible completions ...>
+*** List may be truncated, max-completions reached. ***
+(@value{GDBP}) b m
+@end smallexample
+
+@noindent
+This behavior can be controlled with the following commands:
+
+@table @code
+@kindex set max-completions
+@item set max-completions @var{limit}
+@itemx set max-completions unlimited
+Set the maximum number of completion candidates.  @value{GDBN} will
+stop looking for more completions once it collects this many candidates.
+This is useful when completing on things like function names as collecting
+all the possible candidates can be time consuming.
+The default value is 200.  A value of zero disables tab-completion.
+Note that setting either no limit or a very large limit can make
+completion slow.
+@kindex show max-completions
+@item show max-completions
+Show the maximum number of candidates that @value{GDBN} will collect and show
+during completion.
+@end table
+
@cindex quotes in commands
@cindex completion of quoted strings
 Sometimes the string you need, while logically a ``word'', may contain
--- a/gdb/symtab.c
+++ b/gdb/symtab.c
@ -60,6 +60,7 @@
 #include "macroscope.h"

 #include "parser-defs.h"
+#include "completer.h"

 /* Forward declarations for local functions.  */

@ -5001,6 +5002,15 @@ static VEC (char_ptr) *return_val;
      completion_list_add_name \
 	(MSYMBOL_NATURAL_NAME (symbol), (sym_text), (len), (text), (word))

+/* Tracker for how many unique completions have been generated.  Used
+   to terminate completion list generation early if the list has grown
+   to a size so large as to be useless.  This helps avoid GDB seeming
+   to lock up in the event the user requests to complete on something
+   vague that necessitates the time consuming expansion of many symbol
+   tables.  */
+
+static completion_tracker_t completion_tracker;
+
 /*  Test to see if the symbol specified by SYMNAME (which is already
   demangled for C++ symbols) matches SYM_TEXT in the first SYM_TEXT_LEN
   characters.  If so, add it to the current completion list.  */
@ -5019,6 +5029,7 @@ completion_list_add_name (const char *symname,

  {
    char *new;
+    enum maybe_add_completion_enum add_status;

    if (word == sym_text)
      {
@ -5040,7 +5051,22 @@ completion_list_add_name (const char *symname,
 	strcat (new, symname);
      }

-    VEC_safe_push (char_ptr, return_val, new);
+    add_status = maybe_add_completion (completion_tracker, new);
+
+    switch (add_status)
+      {
+      case MAYBE_ADD_COMPLETION_OK:
+	VEC_safe_push (char_ptr, return_val, new);
+	break;
+      case MAYBE_ADD_COMPLETION_OK_MAX_REACHED:
+	VEC_safe_push (char_ptr, return_val, new);
+	throw_max_completions_reached_error ();
+      case MAYBE_ADD_COMPLETION_MAX_REACHED:
+	throw_max_completions_reached_error ();
+      case MAYBE_ADD_COMPLETION_DUPLICATE:
+	xfree (new);
+	break;
+      }
  }
 }

@ -5253,11 +5279,11 @@ symtab_expansion_callback (struct compunit_symtab *symtab,
 			  datum->code);
 }

-VEC (char_ptr) *
-default_make_symbol_completion_list_break_on (const char *text,
-					      const char *word,
-					      const char *break_on,
-					      enum type_code code)
+static void
+default_make_symbol_completion_list_break_on_1 (const char *text,
+						const char *word,
+						const char *break_on,
+						enum type_code code)
 {
  /* Problem: All of the symbols have to be copied because readline
     frees them.  I'm not going to worry about this; hopefully there
@ -5275,7 +5301,7 @@ default_make_symbol_completion_list_break_on (const char *text,
  /* Length of sym_text.  */
  int sym_text_len;
  struct add_name_data datum;
-  struct cleanup *back_to;
+  struct cleanup *cleanups;

  /* Now look for the symbol we are supposed to complete on.  */
  {
@ -5310,7 +5336,7 @@ default_make_symbol_completion_list_break_on (const char *text,
      /* A double-quoted string is never a symbol, nor does it make sense
         to complete it any other way.  */
      {
-	return NULL;
+	return;
      }
    else
      {
@ -5346,8 +5372,8 @@ default_make_symbol_completion_list_break_on (const char *text,
    }
  gdb_assert (sym_text[sym_text_len] == '\0' || sym_text[sym_text_len] == '(');

-  return_val = NULL;
-  back_to = make_cleanup (do_free_completion_list, &return_val);
+  completion_tracker = new_completion_tracker ();
+  cleanups = make_cleanup_free_completion_tracker (&completion_tracker);

  datum.sym_text = sym_text;
  datum.sym_text_len = sym_text_len;
@ -5461,8 +5487,34 @@ default_make_symbol_completion_list_break_on (const char *text,
      macro_for_each (macro_user_macros, add_macro_name, &datum);
    }

+  do_cleanups (cleanups);
+}
+
+VEC (char_ptr) *
+default_make_symbol_completion_list_break_on (const char *text,
+					      const char *word,
+					      const char *break_on,
+					      enum type_code code)
+{
+  struct cleanup *back_to;
+  volatile struct gdb_exception except;
+
+  return_val = NULL;
+  back_to = make_cleanup (do_free_completion_list, &return_val);
+
+  TRY_CATCH (except, RETURN_MASK_ERROR)
+    {
+      default_make_symbol_completion_list_break_on_1 (text, word,
+						      break_on, code);
+    }
+  if (except.reason < 0)
+    {
+      if (except.error != MAX_COMPLETIONS_REACHED_ERROR)
+	throw_exception (except);
+    }
+
  discard_cleanups (back_to);
-  return (return_val);
+  return return_val;
 }

 VEC (char_ptr) *
--- a/gdb/testsuite/gdb.base/completion.exp
+++ b/gdb/testsuite/gdb.base/completion.exp
@ -67,6 +67,7 @@ if ![runto_main] then {
 }

 set timeout 30
+gdb_test_no_output "set max-completions unlimited"

 gdb_test_no_output "complete print values\[0\].x." \
    "field completion with invalid field"
@ -775,4 +776,86 @@ gdb_test_multiple "" "$test" {
    }
 }

-return 0
+#
+# Completion limiting.
+#
+
+gdb_test_no_output "set max-completions 5"
+
+set test "command-name completion limiting using tab character"
+send_gdb "p\t"
+gdb_test_multiple "" "$test" {
+    -re "^p\\\x07$" {
+	send_gdb "\t"
+	gdb_test_multiple "" "$test" {
+	    -re "List may be truncated, max-completions reached.*\r\n$gdb_prompt p$" {
+		# Complete the command and ignore the output to resync
+		# gdb for the next test.
+		send_gdb "\n"
+		gdb_test_multiple "" "$test" {
+		    -re "$gdb_prompt $" {
+			pass "$test"
+		    }
+		}
+	    }
+	    -re "$gdb_prompt p$" {
+		# Complete the command and ignore the output to resync
+		# gdb for the next test.
+		send_gdb "\n"
+		gdb_test_multiple "" "$test" {
+		    -re "$gdb_prompt $" {
+			fail "$test"
+		    }
+		}
+	    }
+        }
+    }
+}
+
+set test "command-name completion limiting using complete command"
+send_gdb "complete p\n"
+gdb_test_multiple "" "$test" {
+    -re "List may be truncated, max-completions reached.*\r\n$gdb_prompt $" {
+	pass "$test"
+    }
+}
+
+gdb_test_no_output "set max-completions 3"
+
+set test "symbol-name completion limiting using tab character"
+send_gdb "p marker\t"
+gdb_test_multiple "" "$test" {
+    -re "^p marker\\\x07$" {
+	send_gdb "\t"
+	gdb_test_multiple "" "$test" {
+	    -re "List may be truncated, max-completions reached.*\r\n$gdb_prompt p marker$" {
+		# Complete the command and ignore the output to resync
+		# gdb for the next test.
+		send_gdb "\n"
+		gdb_test_multiple "" "$test" {
+		    -re "$gdb_prompt $" {
+			pass "$test"
+		    }
+		}
+	    }
+	    -re "$gdb_prompt p marker$" {
+		# Complete the command and ignore the output to resync
+		# gdb for the next test.
+		send_gdb "\n"
+		gdb_test_multiple "" "$test" {
+		    -re "$gdb_prompt $" {
+			fail "$test"
+		    }
+		}
+	    }
+        }
+    }
+}
+
+set test "symbol-name completion limiting using complete command"
+send_gdb "complete p mark\n"
+gdb_test_multiple "" "$test" {
+    -re "List may be truncated, max-completions reached.*\r\n$gdb_prompt $" {
+	pass "$test"
+    }
+}
--- a/gdb/testsuite/gdb.linespec/ls-errs.exp
+++ b/gdb/testsuite/gdb.linespec/ls-errs.exp
@ -26,6 +26,9 @@ if {[prepare_for_testing $testfile $exefile $srcfile \
 # Turn off the pending breakpoint queries.
 gdb_test_no_output "set breakpoint pending off"

+# Turn off completion limiting
+gdb_test_no_output "set max-completions unlimited"
+
 # We intentionally do not use gdb_breakpoint for these tests.

 # Break at 'linespec' and expect the message in ::error_messages indexed by
--- a/gdb/tui/tui-io.c
+++ b/gdb/tui/tui-io.c
@ -132,6 +132,7 @@ static rl_getc_func_t *tui_old_rl_getc_function;
 static rl_voidfunc_t *tui_old_rl_redisplay_function;
 static rl_vintfunc_t *tui_old_rl_prep_terminal;
 static rl_voidfunc_t *tui_old_rl_deprep_terminal;
+static rl_compdisp_func_t *tui_old_rl_display_matches_hook;
 static int tui_old_rl_echoing_p;

 /* Readline output stream.
@ -468,6 +469,7 @@ tui_setup_io (int mode)
      tui_old_rl_deprep_terminal = rl_deprep_term_function;
      tui_old_rl_prep_terminal = rl_prep_term_function;
      tui_old_rl_getc_function = rl_getc_function;
+      tui_old_rl_display_matches_hook = rl_completion_display_matches_hook;
      tui_old_rl_outstream = rl_outstream;
      tui_old_rl_echoing_p = _rl_echoing_p;
      rl_redisplay_function = tui_redisplay_readline;
@ -511,8 +513,8 @@ tui_setup_io (int mode)
      rl_deprep_term_function = tui_old_rl_deprep_terminal;
      rl_prep_term_function = tui_old_rl_prep_terminal;
      rl_getc_function = tui_old_rl_getc_function;
+      rl_completion_display_matches_hook = tui_old_rl_display_matches_hook;
      rl_outstream = tui_old_rl_outstream;
-      rl_completion_display_matches_hook = 0;
      _rl_echoing_p = tui_old_rl_echoing_p;
      rl_already_prompted = 0;