Re: RFA: interactive command to enable parser debugging

[Tom Tromey <tromey@redhat.com>]

>>>>> "Eli" == Eli Zaretskii <eliz@gnu.org> writes:

Eli> I would also consider saying explicitly that this option sets the
Eli> value of `yydebug', because whoever wants to debug the parser is
Eli> probably familiar with what `yydebug' does.

How about this?  I did that, added the index entries you suggested,
rearranged things so that set comes before show (the other items in the
list all do this, which I didn't notice the first time), and finally
added a link to the bison manual.

Tom

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  Tom Tromey  <tromey@redhat.com>

	* gdb.texinfo (Debugging Output): Document set debug parser and
	show debug parser.

Index: c-exp.y
===================================================================
RCS file: /cvs/src/src/gdb/c-exp.y,v
retrieving revision 1.69
diff -u -r1.69 c-exp.y
--- c-exp.y	18 Jan 2010 20:54:33 -0000	1.69
+++ c-exp.y	10 Feb 2010 17:44:21 -0000
@@ -2450,6 +2450,9 @@
   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;
Index: parse.c
===================================================================
RCS file: /cvs/src/src/gdb/parse.c,v
retrieving revision 1.94
diff -u -r1.94 parse.c
--- parse.c	18 Jan 2010 20:54:34 -0000	1.94
+++ parse.c	10 Feb 2010 17:44:22 -0000
@@ -109,6 +109,18 @@
   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 @@
 			    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);
 }
Index: parser-defs.h
===================================================================
RCS file: /cvs/src/src/gdb/parser-defs.h,v
retrieving revision 1.32
diff -u -r1.32 parser-defs.h
--- parser-defs.h	1 Jan 2010 07:31:38 -0000	1.32
+++ parser-defs.h	10 Feb 2010 17:44:22 -0000
@@ -29,6 +29,8 @@
 
 struct block;
 
+extern int parser_debug;
+
 extern struct expression *expout;
 extern int expout_size;
 extern int expout_ptr;
Index: doc/gdb.texinfo
===================================================================
RCS file: /cvs/src/src/gdb/doc/gdb.texinfo,v
retrieving revision 1.666
diff -u -r1.666 gdb.texinfo
--- doc/gdb.texinfo	9 Feb 2010 18:58:57 -0000	1.666
+++ doc/gdb.texinfo	10 Feb 2010 17:44:27 -0000
@@ -18848,6 +18848,15 @@
 @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