/* Remap file names for debug info for GNU assembler.
   Copyright (C) 2007-2022 Free Software Foundation, Inc.

   This file is part of GAS, the GNU Assembler.

   GAS is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3, or (at your option)
   any later version.

   GAS 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 a copy of the GNU General Public License
   along with GAS; see the file COPYING.  If not, write to the Free
   Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA
   02110-1301, USA.  */

#include "as.h"
#include "filenames.h"

/* Structure recording the mapping from source file and directory
   names at compile time to those to be embedded in debug
   information.  */
typedef struct debug_prefix_map
{
  const char *old_prefix;
  const char *new_prefix;
  size_t old_len;
  size_t new_len;
  struct debug_prefix_map *next;
} debug_prefix_map;

/* Linked list of such structures.  */
debug_prefix_map *debug_prefix_maps;


/* Record a debug file prefix mapping.  ARG is the argument to
   -fdebug-prefix-map and must be of the form OLD=NEW.  */

void
add_debug_prefix_map (const char *arg)
{
  debug_prefix_map *map;
  const char *p;
  char *o;

  p = strchr (arg, '=');
  if (!p)
    {
      as_fatal (_("invalid argument '%s' to -fdebug-prefix-map"), arg);
      return;
    }
  map = XNEW (debug_prefix_map);
  o = xstrdup (arg);
  map->old_prefix = o;
  map->old_len = p - arg;
  o[map->old_len] = 0;
  p++;
  map->new_prefix = xstrdup (p);
  map->new_len = strlen (p);
  map->next = debug_prefix_maps;
  debug_prefix_maps = map;
}

/* Perform user-specified mapping of debug filename prefixes.  Returns
   a newly allocated buffer containing the name corresponding to FILENAME.
   It is the caller's responsibility to free the buffer.  */

char *
remap_debug_filename (const char *filename)
{
  debug_prefix_map *map;

  for (map = debug_prefix_maps; map; map = map->next)
    if (filename_ncmp (filename, map->old_prefix, map->old_len) == 0)
      break;
  if (!map)
    return xstrdup (filename);
  const char *name = filename + map->old_len;
  size_t name_len = strlen (name) + 1;
  char *s = (char *) xmalloc (name_len + map->new_len);
  memcpy (s, map->new_prefix, map->new_len);
  memcpy (s + map->new_len, name, name_len);
  return s;
}