/* Print all locations in the whole DIE tree of a single file using
   dwfl to handle ET_REL files (which need the .debug sections to be
   relocated) and to automatically get separate debuginfo.

   gcc -Wall -Wextra -g -O2 -o dwfl_dwarf dwfl_dwarf.c -ldw
*/

/* We want the sane basename function. */
#define _GNU_SOURCE
#include <string.h>
#include <stdbool.h>
#include <stdio.h>
#include <inttypes.h>

#include <dwarf.h>
#include <elfutils/libdw.h>
#include <elfutils/libdwfl.h>

void
handle_die (Dwarf_Die *die)
{
  do
    {
      Dwarf_Attribute attr;
      if ((dwarf_attr (die, DW_AT_location, &attr) != NULL))
	{
	  printf ("[%" PRIx64 "]", dwarf_dieoffset (die));
	  ptrdiff_t off = 0;
	  Dwarf_Addr base, start, end;
	  do
	    {
	      Dwarf_Op *expr;
	      size_t exprlen;
	      off = dwarf_getlocations(&attr, off, &base, &start, &end,
				       &expr, &exprlen);
	      if (off > 0)
		printf ("(%" PRIx64 ",%" PRIx64 ")[%zd] ",
			start, end, exprlen);
	    }
	  while (off > 0);
	  printf ("\n");
	}

      Dwarf_Die child;
      if (dwarf_child (die, &child) == 0)
	handle_die (&child);
    }
  while (dwarf_siblingof (die, die) == 0);
}

static const Dwfl_Callbacks dwfl_callbacks =
  {
    .find_debuginfo = dwfl_standard_find_debuginfo,
    .section_address = dwfl_offline_section_address,
    .find_elf = dwfl_build_id_find_elf,
  };

int main (int argc, char **argv)
{
  if (argc == 2)
    {
      const char *file = argv[1];
      const char *base = basename (file);
      /* Create a one elf module file Dwfl. */
      Dwfl *dwfl = dwfl_begin (&dwfl_callbacks);
      dwfl_report_begin (dwfl);
      Dwfl_Module *mod = dwfl_report_elf (dwfl, base, file, -1, 0, true);
      dwfl_report_end (dwfl, NULL, NULL);

      Dwarf_Addr bias;
      Dwarf *dbg = dwfl_module_getdwarf(mod, &bias);
      if (dbg != NULL)
	{
	   /* Should be zero with one module. */
	  printf ("bias: %" PRIx64 "\n", bias);
	  Dwarf_CU *cu = NULL;
	  Dwarf_Half version;
	  Dwarf_Die cudie, subdie;
	  uint8_t unit_type;
	  while (dwarf_get_units (dbg, cu, &cu, &version, &unit_type,
				  &cudie, &subdie) == 0)
	    handle_die (&cudie);
	}
      dwfl_end (dwfl);
    }
}