diff --git a/gdb/linespec.c b/gdb/linespec.c
index 37ec368..721bf12 100644
--- a/gdb/linespec.c
+++ b/gdb/linespec.c
@@ -43,6 +43,7 @@
 #include "arch-utils.h"
 #include <ctype.h>
 #include "cli/cli-utils.h"
+#include "filenames.h"
 
 /* Prototypes for local functions.  */
 
@@ -1194,6 +1195,16 @@ locate_first_half (char **argptr, int *is_quote_enclosed)
 	  ++p;
 	}
     }
+
+
+  /* Check for a drive letter in the filename.  This is done on all hosts
+     to capture cross-compilation environments.  On Unixen, directory
+     separators are illegal in filenames, so if the user enters "e:/foo.c",
+     he is referring to a directory named "e:" and a source file named
+     "foo.c", and we still want to keep these two pieces together.  */
+  if (isalpha (p[0]) && p[1] == ':' && IS_DIR_SEPARATOR (p[2]))
+    p += 3;
+
   for (; *p; p++)
     {
       if (p[0] == '<')
@@ -1218,8 +1229,7 @@ locate_first_half (char **argptr, int *is_quote_enclosed)
          line, a tab, a colon or a space.  But if enclosed in double
 	 quotes we do not break on enclosed spaces.  */
       if (!*p
-	  || p[0] == '\t'
-	  || (p[0] == ':')
+	  || p[0] == '\t' || p[0] == ':'
 	  || ((p[0] == ' ') && !*is_quote_enclosed))
 	break;
       if (p[0] == '.' && strchr (p, ':') == NULL)
diff --git a/gdb/testsuite/gdb.base/linespecs.exp b/gdb/testsuite/gdb.base/linespecs.exp
new file mode 100644
index 0000000..bd07779
--- /dev/null
+++ b/gdb/testsuite/gdb.base/linespecs.exp
@@ -0,0 +1,29 @@
+# Copyright 2011 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/>.
+
+# Linespec tests
+
+# We don't currently need our own test case for testing, so grab
+# another one.
+
+if {[prepare_for_testing linespecs.exp memattr memattr.c {debug}]} {
+  return -1
+}
+
+# PR gdb/12843
+gdb_test "list c:/foo/bar/baz.c:1" "No source file named c:/foo/bar/baz.c."
+gdb_test "list c:/foo/bar/baz.c" "Function \"c:/foo/bar/baz.c\" not defined."
+gdb_test "list fooc:/foo/bar/baz.c:1" "No source file named fooc."
+gdb_test "list fooc:/foo/bar/baz.c" "No source file named fooc."