Question about getting GNU Cobol work with GDB

[Simon Sobisch <simonsobisch at web dot de>]

[posted before to gdb@gnu.org]

Hi co-hackers,

GNU Cobol (formerly OpenCOBOL) translates COBOL to C (compiling it with GCC later on).
We try to use GDB as debugging frontend but are unsure how some points can be reached without actually patching the GDB (if it's possible at all).
As one of the maintainers of GNU Cobol I write to you with the hope that we can get as far as possible.

A sample is attached, snippets:

HELLO.cob:

               INSPECT user-input REPLACING TRAILING SPACES BY LOW-VALUE
               MOVE SPACES TO output-msg
               STRING 'Hello "'  DELIMITED BY SIZE
                      user-input DELIMITED BY LOW-VALUE
                      '"!'       DELIMITED BY SIZE
                      INTO output-msg
               END-STRING

HELLO.c[h,l.h]

static cob_field f_6	= {80, b_6, &a_1};	/* output-msg */
static cob_field f_7	= {50, NULL, &a_1};	/* user-input */

static int
HELLO_ (const int entry)


	// [...]

         unsigned char	*b_7 = NULL;	/* user-input */

	// [...]

         /* HELLO.cob:23: INSPECT */

         cob_set_location ("HELLO", "HELLO.cob", 23, "MAIN SECTION", "MAIN PARAGRAPH", "INSPECT");
         {
           cob_inspect_init ((f_7.data = b_7, &f_7), 1);
           cob_inspect_start ();
           cob_inspect_trailing (&cob_low, &cob_space);
           cob_inspect_finish ();
         }
         /* HELLO.cob:24: MOVE */
         cob_set_location ("HELLO", "HELLO.cob", 24, "MAIN SECTION", "MAIN PARAGRAPH", "MOVE");
         {
           memset (b_6, 32, 80);
         }
         /* HELLO.cob:25: STRING */
         cob_set_location ("HELLO", "HELLO.cob", 25, "MAIN SECTION", "MAIN PARAGRAPH", "STRING");
         {
           cob_string_init (&f_6, 0);
           cob_string_delimited (0);
           cob_string_append (&c_3);
           cob_string_delimited (&cob_low);
           cob_string_append ((f_7.data = b_7, &f_7));
           cob_string_delimited (0);
           cob_string_append (&c_4);
           cob_string_finish ();
         }

	// [...]
}

Not clear is how to
- let the programmer see only the COBOL source, not the C source, while stepping
- let the programmer view/change/... COBOL variables (there is a mapping like you can see above)
- set breakpoints within the COBOL source

We're free to add directives and other necessary stuff into the generated C files, even performing "stuff" at runtime, if this helps.

Thank you for your answers,
Simon Sobisch

Attachment: HELLO.c.h
Description: Text document

Attachment: HELLO.c.l.h
Description: Text document

Attachment: HELLO.cob
Description: Text document

Attachment: HELLO.c
Description: Text document