gdb

* parser-defs.h (parser_debug): Declare.
	* parse.c (_initialize_parse): Install "debug parser" set/show
	command.
	(parser_debug): New global.
	(show_parserdebug): New function.
	* c-exp.y (c_parse): Set yydebug.
gdb/testsuite
	* gdb.texinfo (Debugging Output): Document set debug parser and
	show debug parser.

gdb/ChangeLog

@@ -1,3 +1,12 @@
+2010-02-10  Tom Tromey  <tromey@redhat.com>
+
+	* parser-defs.h (parser_debug): Declare.
+	* parse.c (_initialize_parse): Install "debug parser" set/show
+	command.
+	(parser_debug): New global.
+	(show_parserdebug): New function.
+	* c-exp.y (c_parse): Set yydebug.
+
 2010-02-10  H.J. Lu  <hongjiu.lu@intel.com>
 
 	* target-descriptions.c (tdesc_type): Add TDESC_TYPE_I387_EXT,

gdb/c-exp.y

@@ -2450,6 +2450,9 @@ c_parse (void)
   gdb_assert (! macro_original_text);
   make_cleanup (scan_macro_cleanup, 0);
 
+  make_cleanup_restore_integer (&yydebug);
+  yydebug = parser_debug;
+
   /* Initialize some state used by the lexer.  */
   last_was_structop = 0;
   saw_name_at_eof = 0;

gdb/doc/ChangeLog

@@ -1,3 +1,8 @@
+2010-02-10  Tom Tromey  <tromey@redhat.com>
+
+	* gdb.texinfo (Debugging Output): Document set debug parser and
+	show debug parser.
+
 2010-02-09  H.J. Lu  <hongjiu.lu@intel.com>
 
 	* gdb.texinfo (Predefined Target Types): Add i387_ext,

gdb/doc/gdb.texinfo

@@ -18848,6 +18848,15 @@ is off.
 @item show debug overload
 Displays the current state of displaying @value{GDBN} C@t{++} overload
 debugging info.
+@cindex expression parser, debugging info
+@cindex debug expression parser
+@item set debug parser
+Turns on or off the display of expression parser debugging output.
+Internally, this sets the @code{yydebug} variable in the expression
+parser.  @xref{Tracing, , Tracing Your Parser, bison, Bison}, for
+details.  The default is off.
+@item show debug parser
+Show the current state of expression parser debugging.
 @cindex packets, reporting on stdout
 @cindex serial connections, debugging
 @cindex debug remote protocol

gdb/parse.c

@@ -109,6 +109,18 @@ show_expressiondebug (struct ui_file *file, int from_tty,
   fprintf_filtered (file, _("Expression debugging is %s.\n"), value);
 }
 
+
+/* Non-zero if an expression parser should set yydebug.  */
+int parser_debug;
+
+static void
+show_parserdebug (struct ui_file *file, int from_tty,
+		  struct cmd_list_element *c, const char *value)
+{
+  fprintf_filtered (file, _("Parser debugging is %s.\n"), value);
+}
+
+
 static void free_funcalls (void *ignore);
 
 static int prefixify_expression (struct expression *);
@@ -1377,4 +1389,12 @@ When non-zero, the internal representation of expressions will be printed."),
 			    NULL,
 			    show_expressiondebug,
 			    &setdebuglist, &showdebuglist);
+  add_setshow_boolean_cmd ("parser", class_maintenance,
+			    &parser_debug, _("\
+Set parser debugging."), _("\
+Show parser debugging."), _("\
+When non-zero, expression parser tracing will be enabled."),
+			    NULL,
+			    show_parserdebug,
+			    &setdebuglist, &showdebuglist);
 }

gdb/parser-defs.h

@@ -29,6 +29,8 @@
 
 struct block;
 
+extern int parser_debug;
+
 extern struct expression *expout;
 extern int expout_size;
 extern int expout_ptr;