libdw/dwarf_macro_getsrcfiles.c

/* Find line information for a given macro.
   Copyright (C) 2014 Red Hat, Inc.
   This file is part of elfutils.

   This file is free software; you can redistribute it and/or modify
   it under the terms of either

     * the GNU Lesser General Public License as published by the Free
       Software Foundation; either version 3 of the License, or (at
       your option) any later version

   or

     * the GNU General Public License as published by the Free
       Software Foundation; either version 2 of the License, or (at
       your option) any later version

   or both in parallel, as here.

   elfutils is distributed in the hope that it will be useful, but
   WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   General Public License for more details.

   You should have received copies of the GNU General Public License and
   the GNU Lesser General Public License along with this program.  If
   not, see <http://www.gnu.org/licenses/>.  */

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif

#include "libdwP.h"

int
dwarf_macro_getsrcfiles (Dwarf *dbg, Dwarf_Macro *macro,
			 Dwarf_Files **files, size_t *nfiles)
{
  /* macro is declared NN */
  Dwarf_Macro_Op_Table *const table = macro->table;
  if (table->files == NULL)
    {
      Dwarf_Off line_offset = table->line_offset;
      if (line_offset == (Dwarf_Off) -1)
	{
	  *files = NULL;
	  *nfiles = 0;
	  return 0;
	}

      /* If TABLE->comp_dir is NULL that could mean any of the
	 following:

	 - The macro unit is not bound to a CU.  It's an auxiliary
           unit used purely for import from other units.  In that case
           there's actually no COMP_DIR value that we could use.

	 - The macro unit is bound to a CU, but there's no
           DW_AT_comp_dir attribute at the CU DIE.

	 - The macro unit is bound to a CU, but we don't know that,
           likely because its iteration was requested through
           dwarf_getmacros_off interface.  This might be legitimate if
           one macro unit imports another CU's macro unit, but that is
           unlikely to happen in practice.  Most probably this is not
           legitimate use of the interfaces.

	 So when the interfaces are used correctly, COMP_DIR value is
	 always right.  That means that we can cache the parsed
	 .debug_line unit without fear that later on someone requests
	 the same unit through dwarf_getsrcfiles, and the file names
	 will be broken.  */

      if (__libdw_getsrclines (dbg, line_offset, table->comp_dir,
			       table->is_64bit ? 8 : 4,
			       NULL, &table->files) < 0)
	table->files = (void *) -1;
    }

  if (table->files == (void *) -1)
    return -1;

  *files = table->files;
  *nfiles = table->files->nfiles;
  return 0;
}