Disallow trailing whitespace in docstrings

This patch changes the docstring self-test to verify that there is no
trailing whitespace at the end of lines.  A few existing docstrings
had to be updated.

gdb/breakpoint.c

@@ -14598,7 +14598,7 @@ command" [PROBE_MODIFIER] [LOCATION] [thread THREADNUM]\n\
 \t[-force-condition] [if CONDITION]\n\
 PROBE_MODIFIER shall be present if the command is to be placed in a\n\
 probe point.  Accepted values are `-probe' (for a generic, automatically\n\
-guessed probe type), `-probe-stap' (for a SystemTap probe) or \n\
+guessed probe type), `-probe-stap' (for a SystemTap probe) or\n\
 `-probe-dtrace' (for a DTrace probe).\n\
 LOCATION may be a linespec, address, or explicit location as described\n\
 below.\n\
@@ -15029,7 +15029,7 @@ Do \"help tracepoints\" for info on other tracepoint commands."));
 Set a static tracepoint at location or marker.\n\
 \n\
 strace [LOCATION] [if CONDITION]\n\
-LOCATION may be a linespec, explicit, or address location (described below) \n\
+LOCATION may be a linespec, explicit, or address location (described below)\n\
 or -m MARKER_ID.\n\n\
 If a marker id is specified, probe the marker with that name.  With\n\
 no LOCATION, uses current execution address of the selected stack frame.\n\

gdb/cris-tdep.c

@@ -3829,7 +3829,7 @@ _initialize_cris_tdep ()
 			     _("Show the current CRIS version."),
 			     _("\
 Set to 10 for CRISv10 or 32 for CRISv32 if autodetection fails.\n\
-Defaults to 10. "),
+Defaults to 10."),
 			     set_cris_version,
 			     NULL, /* FIXME: i18n: Current CRIS version
 				      is %s.  */

gdb/infcmd.c

@@ -3077,7 +3077,7 @@ shell that will start the program (specified by the \"$SHELL\" environment\n\
 variable).  Input and output redirection with \">\", \"<\", or \">>\"\n\
 are also allowed.\n\
 \n\
-With no arguments, uses arguments last specified (with \"run\" or \n\
+With no arguments, uses arguments last specified (with \"run\" or\n\
 \"set args\").  To cancel previous arguments and run with no arguments,\n\
 use \"set args\" without arguments.\n\
 \n\
@@ -3303,7 +3303,7 @@ which means to set the ignore count of that breakpoint to N - 1 (so that\n\
 the breakpoint won't break until the Nth time it is reached).\n\
 \n\
 If non-stop mode is enabled, continue only the current thread,\n\
-otherwise all the threads in the program are continued.  To \n\
+otherwise all the threads in the program are continued.  To\n\
 continue all stopped threads in non-stop mode, use the -a option.\n\
 Specifying -a and an ignore count simultaneously is an error."));
   add_com_alias ("c", continue_cmd, class_run, 1);
@@ -3329,7 +3329,7 @@ RUN_ARGS_HELP));
   add_com ("interrupt", class_run, interrupt_command,
 	   _("Interrupt the execution of the debugged program.\n\
 If non-stop mode is enabled, interrupt only the current thread,\n\
-otherwise all the threads in the program are stopped.  To \n\
+otherwise all the threads in the program are stopped.  To\n\
 interrupt all running threads in non-stop mode, use the -a option."));
 
   cmd_list_element *info_registers_cmd

gdb/macrocmd.c

@@ -480,7 +480,7 @@ expression work together to yield a pre-processed expression."),
   add_info ("macro", info_macro_command,
 	    _("Show the definition of MACRO, and it's source location.\n\
 Usage: info macro [-a|-all] [--] MACRO\n\
-Options: \n\
+Options:\n\
   -a, --all    Output all definitions of MACRO in the current compilation\
  unit.\n\
   --           Specify the end of arguments and the beginning of the MACRO."));

gdb/reverse.c

@@ -320,12 +320,12 @@ Execute backward until just before selected stack frame is called."));
 
   add_com ("bookmark", class_bookmark, save_bookmark_command, _("\
 Set a bookmark in the program's execution history.\n\
-A bookmark represents a point in the execution history \n\
+A bookmark represents a point in the execution history\n\
 that can be returned to at a later point in the debug session."));
   add_info ("bookmarks", info_bookmarks_command, _("\
 Status of user-settable bookmarks.\n\
-Bookmarks are user-settable markers representing a point in the \n\
-execution history that can be returned to later in the same debug \n\
+Bookmarks are user-settable markers representing a point in the\n\
+execution history that can be returned to later in the same debug\n\
 session."));
   add_cmd ("bookmark", class_bookmark, delete_bookmark_command, _("\
 Delete a bookmark from the bookmark list.\n\
@@ -334,7 +334,7 @@ Argument is a bookmark number or numbers,\n\
 	   &deletelist);
   add_com ("goto-bookmark", class_bookmark, goto_bookmark_command, _("\
 Go to an earlier-bookmarked point in the program's execution history.\n\
-Argument is the bookmark number of a bookmark saved earlier by using \n\
+Argument is the bookmark number of a bookmark saved earlier by using\n\
 the 'bookmark' command, or the special arguments:\n\
   start (beginning of recording)\n\
   end   (end of recording)"));

gdb/skip.c

@@ -723,7 +723,7 @@ If you don't specify any numbers or ranges, we'll delete all skip entries."),
   add_info ("skip", info_skip_command, _("\
 Display the status of skips.\n\
 Usage: info skip [NUMBER | RANGES]...\n\
-You can specify numbers (e.g. \"info skip 1 3\"), \n\
+You can specify numbers (e.g. \"info skip 1 3\"),\n\
 ranges (e.g. \"info skip 4-8\"), or both (e.g. \"info skip 1 3 4-8\").\n\n\
 If you don't specify any numbers or ranges, we'll show all skips."));
   set_cmd_completer (c, complete_skip_number);

gdb/typeprint.c

@@ -843,7 +843,7 @@ Available FLAGS are:\n\
   /x    use hexadecimal notation when displaying sizes and offsets\n\
 	of struct members\n\
   /d    use decimal notation when displaying sizes and offsets\n\
-	of struct members "));
+	of struct members"));
   set_cmd_completer (c, expression_completer);
 
   c = add_com ("whatis", class_vars, whatis_command,

gdb/unittests/command-def-selftests.c

@@ -73,10 +73,25 @@ check_doc (struct cmd_list_element *commandlist, const char *prefix)
 	   "first line is not terminated with a '.' character");
 
       /* Checks the doc is not terminated with a new line.  */
-      if (c->doc[strlen (c->doc) - 1] == '\n')
+      if (isspace (c->doc[strlen (c->doc) - 1]))
 	broken_doc_invariant
 	  (prefix, c->name,
-	   "has a superfluous trailing end of line");
+	   "has superfluous trailing whitespace");
+
+      for (const char *nl = strchr (c->doc, '\n');
+	   nl != nullptr;
+	   nl = strchr (nl + 1, '\n'))
+	{
+	  if (nl == c->doc)
+	    broken_doc_invariant (prefix, c->name, "has a leading newline");
+	  else
+	    {
+	      /* \n\n is ok, so we check that explicitly here.  */
+	      if (isspace (nl[-1]) && nl[-1] != '\n')
+		broken_doc_invariant (prefix, c->name,
+				      "has whitespace before a newline");
+	    }
+	}
 
       /* Check if this command has subcommands and is not an
 	 abbreviation.  We skip checking subcommands of abbreviations