/*
  //tag[@name='DW_TAG_structure_type']
 */
#include <stdio.h>
#include <assert.h>
#include <stdlib.h>

#include <libelf.h>
#include <dwarf.h>
#include <libdwarf.h>

static Dwarf_Debug debug;
static Dwarf_Error error;

struct die_list {
    Dwarf_Die       die;
    struct die_list *next;
};

struct die_list *
add_die (Dwarf_Die die, struct die_list *die_list)
{
    struct die_list *new = malloc (sizeof (struct die_list));
    assert (new != NULL);
    new->die = die;
    new->next = die_list;
    return new;
}

struct die_list *
collect_all_struct_sub (Dwarf_Die die, struct die_list *die_list)
{
    int             ret;
    Dwarf_Half      tagval;
    Dwarf_Die 	    child_die;

    ret = dwarf_tag (die, &tagval, NULL);
    assert (ret == DW_DLV_OK);
    if (tagval == DW_TAG_structure_type) {
	Dwarf_Off off;
	ret = dwarf_dieoffset (die, &off, NULL);
	assert (ret == DW_DLV_OK);
	printf ("struct: %d\n", (int)off);
	die_list = add_die (die, die_list);
    }

    /* visit all children */
    ret = dwarf_child (die, &child_die, NULL);
    assert (ret != DW_DLV_ERROR);
    if (ret == DW_DLV_NO_ENTRY)
	return die_list;

    while (1) {
	Dwarf_Die sibling_die;
	die_list = collect_all_struct_sub (child_die, die_list);
	ret = dwarf_siblingof (debug, child_die, &sibling_die, NULL);
	assert (ret != DW_DLV_ERROR);
	if (ret == DW_DLV_NO_ENTRY)
	    break;
	child_die = sibling_die;
    }
    return die_list;
}

struct die_list *
collect_all_struct (void)
{
    int             ret;
    Dwarf_Die       die;
    Dwarf_Half      tagval;
    Dwarf_Unsigned  next_cu_header;
    struct die_list *die_list = NULL;

    while (1) {
	ret = dwarf_next_cu_header (debug, NULL, NULL, NULL, NULL,
				    &next_cu_header, NULL);
	if (ret == DW_DLV_NO_ENTRY) break;
	assert (ret == DW_DLV_OK);

	ret = dwarf_siblingof (debug, 0, &die, NULL);
	assert (ret != DW_DLV_ERROR);
	ret = dwarf_tag (die, &tagval, NULL);
	assert (ret == DW_DLV_OK);
	assert (tagval == DW_TAG_compile_unit);
	
	die_list = collect_all_struct_sub (die, die_list);
    }
    return die_list;
}

int
main (int argc, char *argv [])
{
    int  ret;
    int  i;
    FILE *fp;
    struct die_list *die_list;

    if (argc < 2) {
	fprintf (stderr, "Usage: %s filename\n", argv [0]);
	exit (1);
    }
    fp = fopen (argv [1], "r");
    if (fp == NULL) {
	perror ("fopen");
	exit (1);
    }
    ret = dwarf_init (fileno(fp), DW_DLC_READ, NULL, NULL, &debug, NULL);
    assert (ret == DW_DLV_OK);

    die_list = collect_all_struct ();

    for (i = 0; ; i++) {
	if (die_list == NULL) break;
	printf ("%d\n", (int)die_list->die);
	die_list = die_list->next;
    }
    printf ("%d\n", i);

    ret = dwarf_finish (debug, NULL);
    assert (ret == DW_DLV_OK);
    fclose (fp);
}