Make gdb.parameter("directories") work.

New command "set directories".
	* NEWS: Document them.
	* source.c (set_directories_command): New function.
	(show_directories_1): Renamed from show_directories.
	All callers updated.
	(show_directories_command): New function.
	(_initialize_source): Install "directories" as a set/show
	variable instead of just a show command.

	doc/
	* gdb.texinfo (Source Path): Document "set directories".

	testsuite/
	* gdb.base/help.exp: Update expected output.
	* gdb.python/py-parameter.exp: New file.

gdb/ChangeLog

@@ -1,3 +1,15 @@
+2010-11-05  Doug Evans  <dje@google.com>
+
+	Make gdb.parameter("directories") work.
+	New command "set directories".
+	* NEWS: Document them.
+	* source.c (set_directories_command): New function.
+	(show_directories_1): Renamed from show_directories.
+	All callers updated.
+	(show_directories_command): New function.
+	(_initialize_source): Install "directories" as a set/show
+	variable instead of just a show command.
+
 2010-11-05  Ken Werner  <ken.werner@de.ibm.com>
 
 	* NEWS: Mention OpenCL C language support.

gdb/NEWS

@@ -3,6 +3,10 @@
 
 *** Changes since GDB 7.2
 
+* GDB has a new command: "set directories".
+  It is like the "dir" command except that it replaces the
+  source path list instead of augmenting it.
+
 * OpenCL C
   Initial support for the OpenCL C language (http://www.khronos.org/opencl)
   has been integrated into GDB.
@@ -29,6 +33,8 @@
   ** New commands "info pretty-printers", "enable pretty-printer" and
      "disable pretty-printer" have been added.
 
+  ** gdb.parameter("directories") is now available.
+
 * C++ Improvements:
 
   ** GDB now puts template parameters in scope when debugging in an

gdb/doc/ChangeLog

@@ -1,3 +1,7 @@
+2010-11-05  Doug Evans  <dje@google.com>
+
+	* gdb.texinfo (Source Path): Document "set directories".
+
 2010-11-05  Ken Werner  <ken.werner@de.ibm.com>
 
 	* gdb.texinfo: (Summary) Add mention about OpenCL C language support.

gdb/doc/gdb.texinfo

@@ -6623,6 +6623,11 @@ Reset the source path to its default value (@samp{$cdir:$cwd} on Unix systems).
 @c RET-repeat for @code{directory} is explicitly disabled, but since
 @c repeating it would be a no-op we do not say that.  (thanks to RMS)
 
+@item set directories @var{path-list}
+@kindex set directories
+Set the source path to @var{path-list}.
+@samp{$cdir:$cwd} are added if missing.
+
 @item show directories
 @kindex show directories
 Print the source path: show which directories it contains.

gdb/source.c

@@ -68,8 +68,6 @@ static void line_info (char *, int);
 
 static void source_info (char *, int);
 
-static void show_directories (char *, int);
-
 /* Path of directories to search for source files.
    Same format as the PATH environment variable's value.  */
 
@@ -293,14 +291,49 @@ select_source_symtab (struct symtab *s)
   error (_("Can't find a default source file"));
 }
 
+/* Handler for "set directories path-list" command.
+   "set dir mumble" doesn't prepend paths, it resets the entire
+   path list.  The theory is that set(show(dir)) should be a no-op.  */
+
 static void
-show_directories (char *ignore, int from_tty)
+set_directories_command (char *args, int from_tty, struct cmd_list_element *c)
+{
+  /* This is the value that was set.
+     It needs to be processed to maintain $cdir:$cwd and remove dups.  */
+  char *set_path = source_path;
+
+  /* We preserve the invariant that $cdir:$cwd begins life at the end of
+     the list by calling init_source_path.  If they appear earlier in
+     SET_PATH then mod_path will move them appropriately.
+     mod_path will also remove duplicates.  */
+  init_source_path ();
+  if (*set_path != '\0')
+    mod_path (set_path, &source_path);
+
+  xfree (set_path);
+}
+
+/* Print the list of source directories.
+   This is used by the "ld" command, so it has the signature of a command
+   function.  */
+
+static void
+show_directories_1 (char *ignore, int from_tty)
 {
   puts_filtered ("Source directories searched: ");
   puts_filtered (source_path);
   puts_filtered ("\n");
 }
 
+/* Handler for "show directories" command.  */
+
+static void
+show_directories_command (struct ui_file *file, int from_tty,
+			  struct cmd_list_element *c, const char *value)
+{
+  show_directories_1 (NULL, from_tty);
+}
+
 /* Forget what we learned about line positions in source files, and
    which directories contain them; must check again now since files
    may be found in a different directory now.  */
@@ -367,7 +400,7 @@ directory_command (char *dirname, int from_tty)
       forget_cached_source_info ();
     }
   if (from_tty)
-    show_directories ((char *) 0, from_tty);
+    show_directories_1 ((char *) 0, from_tty);
 }
 
 /* Add a path given with the -d command line switch.
@@ -1938,16 +1971,27 @@ With no argument, reset the search path to $cdir:$cwd, the default."),
 
   set_cmd_completer (c, filename_completer);
 
-  add_cmd ("directories", no_class, show_directories, _("\
+  add_setshow_optional_filename_cmd ("directories",
-Current search path for finding source files.\n\
+				     class_files,
+				     &source_path,
+				     _("\
+Set the search path for finding source files."),
+				     _("\
+Show the search path for finding source files."),
+				     _("\
 $cwd in the path means the current working directory.\n\
-$cdir in the path means the compilation directory of the source file."),
+$cdir in the path means the compilation directory of the source file.\n\
-	   &showlist);
+GDB ensures the search path always ends with $cdir:$cwd by\n\
+appending these directories if necessary.\n\
+Setting the value to an empty string sets it to $cdir:$cwd, the default."),
+			    set_directories_command,
+			    show_directories_command,
+			    &setlist, &showlist);
 
   if (xdb_commands)
     {
       add_com_alias ("D", "directory", class_files, 0);
-      add_cmd ("ld", no_class, show_directories, _("\
+      add_cmd ("ld", no_class, show_directories_1, _("\
 Current search path for finding source files.\n\
 $cwd in the path means the current working directory.\n\
 $cdir in the path means the compilation directory of the source file."),

gdb/testsuite/ChangeLog

@@ -1,3 +1,8 @@
+2010-11-05  Doug Evans  <dje@google.com>
+
+	* gdb.base/help.exp: Update expected output.
+	* gdb.python/py-parameter.exp: New file.
+
 2010-11-05  Ken Werner  <ken.werner@de.ibm.com>
 
 	* Makefile.in (ALL_SUBDIRS): Add gdb.opencl.

gdb/testsuite/gdb.base/help.exp

@@ -507,7 +507,7 @@ gdb_test "help show confirm" "Show whether to confirm potentially dangerous oper
 # test help show convenience
 gdb_test "help show convenience" "Debugger convenience \\(\"\\\$foo\"\\) variables\.\[\r\n\]+These variables are created when you assign them values;\[\r\n\]+thus, \"print \\\$foo=1\" gives \"\\\$foo\" the value 1\.  Values may be any type\.\[\r\n\]+A few convenience variables are given values automatically:\[\r\n\]+\"\\\$_\"holds the last address examined with \"x\" or \"info lines\",\[\r\n\]+\"\\\$__\" holds the contents of the last address examined with \"x\"\." "help show convenience"
 # test help show directories
-gdb_test "help show directories" "Current search path for finding source files\.\[\r\n\]+\\\$cwd in the path means the current working directory\.\[\r\n\]+\\\$cdir in the path means the compilation directory of the source file\." "help show directories"
+gdb_test "help show directories" "Show the search path for finding source files\.\[\r\n\]+\\\$cwd in the path means the current working directory\.\[\r\n\]+\\\$cdir in the path means the compilation directory of the source file\..*" "help show directories"
 # test help show editing
 gdb_test "help show editing" "Show editing of command lines as they are typed\.\[\r\n\]+Use \"on\" to enable the editing, and \"off\" to disable it\.\[\r\n\]+Without an argument, command line editing is enabled\.  To edit, use\[\r\n\]+EMACS-like or VI-like commands like control-P or ESC\." "help show editing"
 # test help show environment

gdb/testsuite/gdb.python/py-parameter.exp

@@ -0,0 +1,33 @@
+# Copyright (C) 2010 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# This file is part of the GDB testsuite.  It tests gdb.parameter.
+
+if $tracelevel then {
+    strace $tracelevel
+}
+
+load_lib gdb-python.exp
+
+# Start with a fresh gdb.
+gdb_exit
+gdb_start
+gdb_reinitialize_dir $srcdir/$subdir
+
+# Skip all tests if Python scripting is not enabled.
+if { [skip_python_tests] } { continue }
+
+# We use "." here instead of ":" so that this works on win32 too.
+gdb_test "python print gdb.parameter ('directories')" "$srcdir/$subdir.\\\$cdir.\\\$cwd"