osprey-gcc/gcc/gengtype.c

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/* Process source files and output type information.
   Copyright (C) 2002, 2003, 2004, 2005 Free Software Foundation, Inc.

This file is part of GCC.

GCC 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 2, or (at your option) any later
version.

GCC 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 GCC; see the file COPYING.  If not, write to the Free
Software Foundation, 59 Temple Place - Suite 330, Boston, MA
02111-1307, USA.  */

#include "bconfig.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "gengtype.h"
#include "gtyp-gen.h"
#include "errors.h"

/* Nonzero iff an error has occurred.  */
static int hit_error = 0;

static void gen_rtx_next (void);
static void write_rtx_next (void);
static void open_base_files (void);
static void close_output_files (void);

/* Report an error at POS, printing MSG.  */

void
error_at_line (struct fileloc *pos, const char *msg, ...)
{
  va_list ap;

  va_start (ap, msg);

  fprintf (stderr, "%s:%d: ", pos->file, pos->line);
  vfprintf (stderr, msg, ap);
  fputc ('\n', stderr);
  hit_error = 1;

  va_end (ap);
}

/* vasprintf, but produces fatal message on out-of-memory.  */
int
xvasprintf (char **result, const char *format, va_list args)
{
  int ret = vasprintf (result, format, args);
  if (*result == NULL || ret < 0)
    {
      fputs ("gengtype: out of memory", stderr);
      xexit (1);
    }
  return ret;
}

/* Wrapper for xvasprintf.  */
char *
xasprintf (const char *format, ...)
{
  char *result;
  va_list ap;

  va_start (ap, format);
  xvasprintf (&result, format, ap);
  va_end (ap);
  return result;
}

/* The one and only TYPE_STRING.  */

struct type string_type = {
  TYPE_STRING, NULL, NULL, GC_USED, {0}
};

/* Lists of various things.  */

static pair_p typedefs;
static type_p structures;
static type_p param_structs;
static pair_p variables;

static void do_scalar_typedef (const char *, struct fileloc *);
static type_p find_param_structure
  (type_p t, type_p param[NUM_PARAM]);
static type_p adjust_field_tree_exp (type_p t, options_p opt);
static type_p adjust_field_rtx_def (type_p t, options_p opt);

/* Define S as a typedef to T at POS.  */

void
do_typedef (const char *s, type_p t, struct fileloc *pos)
{
  pair_p p;

  for (p = typedefs; p != NULL; p = p->next)
    if (strcmp (p->name, s) == 0)
      {
  if (p->type != t)
    {
      error_at_line (pos, "type `%s' previously defined", s);
      error_at_line (&p->line, "previously defined here");
    }
  return;
      }

  p = XNEW (struct pair);
  p->next = typedefs;
  p->name = s;
  p->type = t;
  p->line = *pos;
  typedefs = p;
}

/* Define S as a typename of a scalar.  */

static void
do_scalar_typedef (const char *s, struct fileloc *pos)
{
  do_typedef (s, create_scalar_type (s, strlen (s)), pos);
}

/* Return the type previously defined for S.  Use POS to report errors.  */

type_p
resolve_typedef (const char *s, struct fileloc *pos)
{
  pair_p p;
  for (p = typedefs; p != NULL; p = p->next)
    if (strcmp (p->name, s) == 0)
      return p->type;
  error_at_line (pos, "unidentified type `%s'", s);
  return create_scalar_type ("char", 4);
}

/* Create a new structure with tag NAME (or a union iff ISUNION is nonzero),
   at POS with fields FIELDS and options O.  */

void
new_structure (const char *name, int isunion, struct fileloc *pos,
         pair_p fields, options_p o)
{
  type_p si;
  type_p s = NULL;
  lang_bitmap bitmap = get_base_file_bitmap (pos->file);

  for (si = structures; si != NULL; si = si->next)
    if (strcmp (name, si->u.s.tag) == 0
  && UNION_P (si) == isunion)
      {
  type_p ls = NULL;
  if (si->kind == TYPE_LANG_STRUCT)
    {
      ls = si;

      for (si = ls->u.s.lang_struct; si != NULL; si = si->next)
        if (si->u.s.bitmap == bitmap)
    s = si;
    }
  else if (si->u.s.line.file != NULL && si->u.s.bitmap != bitmap)
    {
      ls = si;
      si = XCNEW (struct type);
      memcpy (si, ls, sizeof (struct type));
      ls->kind = TYPE_LANG_STRUCT;
      ls->u.s.lang_struct = si;
      ls->u.s.fields = NULL;
      si->next = NULL;
      si->pointer_to = NULL;
      si->u.s.lang_struct = ls;
    }
  else
    s = si;

  if (ls != NULL && s == NULL)
    {
      s = XCNEW (struct type);
      s->next = ls->u.s.lang_struct;
      ls->u.s.lang_struct = s;
      s->u.s.lang_struct = ls;
    }
  break;
      }

  if (s == NULL)
    {
      s = XCNEW (struct type);
      s->next = structures;
      structures = s;
    }

  if (s->u.s.line.file != NULL
      || (s->u.s.lang_struct && (s->u.s.lang_struct->u.s.bitmap & bitmap)))
    {
      error_at_line (pos, "duplicate structure definition");
      error_at_line (&s->u.s.line, "previous definition here");
    }

  s->kind = isunion ? TYPE_UNION : TYPE_STRUCT;
  s->u.s.tag = name;
  s->u.s.line = *pos;
  s->u.s.fields = fields;
  s->u.s.opt = o;
  s->u.s.bitmap = bitmap;
  if (s->u.s.lang_struct)
    s->u.s.lang_struct->u.s.bitmap |= bitmap;
}

/* Return the previously-defined structure with tag NAME (or a union
   iff ISUNION is nonzero), or a new empty structure or union if none
   was defined previously.  */

type_p
find_structure (const char *name, int isunion)
{
  type_p s;

  for (s = structures; s != NULL; s = s->next)
    if (strcmp (name, s->u.s.tag) == 0
  && UNION_P (s) == isunion)
      return s;

  s = XCNEW (struct type);
  s->next = structures;
  structures = s;
  s->kind = isunion ? TYPE_UNION : TYPE_STRUCT;
  s->u.s.tag = name;
  structures = s;
  return s;
}

/* Return the previously-defined parameterized structure for structure
   T and parameters PARAM, or a new parameterized empty structure or
   union if none was defined previously.  */

static type_p
find_param_structure (type_p t, type_p param[NUM_PARAM])
{
  type_p res;

  for (res = param_structs; res; res = res->next)
    if (res->u.param_struct.stru == t
  && memcmp (res->u.param_struct.param, param,
       sizeof (type_p) * NUM_PARAM) == 0)
      break;
  if (res == NULL)
    {
      res = XCNEW (struct type);
      res->kind = TYPE_PARAM_STRUCT;
      res->next = param_structs;
      param_structs = res;
      res->u.param_struct.stru = t;
      memcpy (res->u.param_struct.param, param, sizeof (type_p) * NUM_PARAM);
    }
  return res;
}

/* Return a scalar type with name NAME.  */

type_p
create_scalar_type (const char *name, size_t name_len)
{
  type_p r = XCNEW (struct type);
  r->kind = TYPE_SCALAR;
  r->u.sc = (char *) xmemdup (name, name_len, name_len + 1);
  return r;
}

/* Return a pointer to T.  */

type_p
create_pointer (type_p t)
{
  if (! t->pointer_to)
    {
      type_p r = XCNEW (struct type);
      r->kind = TYPE_POINTER;
      r->u.p = t;
      t->pointer_to = r;
    }
  return t->pointer_to;
}

/* Return an array of length LEN.  */

type_p
create_array (type_p t, const char *len)
{
  type_p v;

  v = XCNEW (struct type);
  v->kind = TYPE_ARRAY;
  v->u.a.p = t;
  v->u.a.len = len;
  return v;
}

/* Return an options structure with name NAME and info INFO.  */
options_p
create_option (const char *name, void *info)
{
  options_p o = XNEW (struct options);
  o->name = name;
  o->info = (const char*) info;
  return o;
}

/* Add a variable named S of type T with options O defined at POS,
   to `variables'.  */

void
note_variable (const char *s, type_p t, options_p o, struct fileloc *pos)
{
  pair_p n;
  n = XNEW (struct pair);
  n->name = s;
  n->type = t;
  n->line = *pos;
  n->opt = o;
  n->next = variables;
  variables = n;
}

/* We don't care how long a CONST_DOUBLE is.  */
#define CONST_DOUBLE_FORMAT "ww"
/* We don't want to see codes that are only for generator files.  */
#undef GENERATOR_FILE

enum rtx_code {
#define DEF_RTL_EXPR(ENUM, NAME, FORMAT, CLASS) ENUM ,
#include "rtl.def"
#undef DEF_RTL_EXPR
  NUM_RTX_CODE
};

static const char * const rtx_name[NUM_RTX_CODE] = {
#define DEF_RTL_EXPR(ENUM, NAME, FORMAT, CLASS)   NAME ,
#include "rtl.def"
#undef DEF_RTL_EXPR
};

static const char * const rtx_format[NUM_RTX_CODE] = {
#define DEF_RTL_EXPR(ENUM, NAME, FORMAT, CLASS)   FORMAT ,
#include "rtl.def"
#undef DEF_RTL_EXPR
};

static int rtx_next_new[NUM_RTX_CODE];

/* We also need codes and names for insn notes (not register notes).
   Note that we do *not* bias the note values here.  */
enum insn_note {
#define DEF_INSN_NOTE(NAME) NAME,
#include "insn-notes.def"
#undef DEF_INSN_NOTE

  NOTE_INSN_MAX
};

/* We must allocate one more entry here, as we use NOTE_INSN_MAX as the
   default field for line number notes.  */
static const char *const note_insn_name[NOTE_INSN_MAX+1] = {
#define DEF_INSN_NOTE(NAME) #NAME,
#include "insn-notes.def"
#undef DEF_INSN_NOTE
};

#undef CONST_DOUBLE_FORMAT
#define GENERATOR_FILE

/* Generate the contents of the rtx_next array.  This really doesn't belong
   in gengtype at all, but it's needed for adjust_field_rtx_def.  */

static void
gen_rtx_next (void)
{
  int i;
  for (i = 0; i < NUM_RTX_CODE; i++)
    {
      int k;

      rtx_next_new[i] = -1;
      if (strncmp (rtx_format[i], "iuu", 3) == 0)
  rtx_next_new[i] = 2;
      else if (i == COND_EXEC || i == SET || i == EXPR_LIST || i == INSN_LIST)
  rtx_next_new[i] = 1;
      else
  for (k = strlen (rtx_format[i]) - 1; k >= 0; k--)
    if (rtx_format[i][k] == 'e' || rtx_format[i][k] == 'u')
      rtx_next_new[i] = k;
    }
}

/* Write out the contents of the rtx_next array.  */
static void
write_rtx_next (void)
{
  outf_p f = get_output_file_with_visibility (NULL);
  int i;

  oprintf (f, "\n/* Used to implement the RTX_NEXT macro.  */\n");
  oprintf (f, "const unsigned char rtx_next[NUM_RTX_CODE] = {\n");
  for (i = 0; i < NUM_RTX_CODE; i++)
    if (rtx_next_new[i] == -1)
      oprintf (f, "  0,\n");
    else
      oprintf (f,
         "  RTX_HDR_SIZE + %d * sizeof (rtunion),\n",
         rtx_next_new[i]);
  oprintf (f, "};\n");
}

/* Handle `special("rtx_def")'.  This is a special case for field
   `fld' of struct rtx_def, which is an array of unions whose values
   are based in a complex way on the type of RTL.  */

static type_p
adjust_field_rtx_def (type_p t, options_p ARG_UNUSED (opt))
{
  pair_p flds = NULL;
  options_p nodot;
  int i;
  type_p rtx_tp, rtvec_tp, tree_tp, mem_attrs_tp, note_union_tp, scalar_tp;
  type_p bitmap_tp, basic_block_tp, reg_attrs_tp;

  if (t->kind != TYPE_UNION)
    {
      error_at_line (&lexer_line,
         "special `rtx_def' must be applied to a union");
      return &string_type;
    }

  nodot = XNEW (struct options);
  nodot->next = NULL;
  nodot->name = "dot";
  nodot->info = "";

  rtx_tp = create_pointer (find_structure ("rtx_def", 0));
  rtvec_tp = create_pointer (find_structure ("rtvec_def", 0));
  tree_tp = create_pointer (find_structure ("tree_node", 1));
  mem_attrs_tp = create_pointer (find_structure ("mem_attrs", 0));
  reg_attrs_tp = create_pointer (find_structure ("reg_attrs", 0));
  bitmap_tp = create_pointer (find_structure ("bitmap_element_def", 0));
  basic_block_tp = create_pointer (find_structure ("basic_block_def", 0));
  scalar_tp = create_scalar_type ("rtunion scalar", 14);

  {
    pair_p note_flds = NULL;
    int c;

    for (c = 0; c <= NOTE_INSN_MAX; c++)
      {
  pair_p old_note_flds = note_flds;

  note_flds = XNEW (struct pair);
  note_flds->line.file = __FILE__;
  note_flds->line.line = __LINE__;
  note_flds->opt = XNEW (struct options);
  note_flds->opt->next = nodot;
  note_flds->opt->name = "tag";
  note_flds->opt->info = note_insn_name[c];
  note_flds->next = old_note_flds;

  switch (c)
    {
      /* NOTE_INSN_MAX is used as the default field for line
         number notes.  */
    case NOTE_INSN_MAX:
      note_flds->opt->name = "default";
      note_flds->name = "rt_str";
      note_flds->type = &string_type;
      break;

    case NOTE_INSN_BLOCK_BEG:
    case NOTE_INSN_BLOCK_END:
      note_flds->name = "rt_tree";
      note_flds->type = tree_tp;
      break;

    case NOTE_INSN_EXPECTED_VALUE:
    case NOTE_INSN_VAR_LOCATION:
      note_flds->name = "rt_rtx";
      note_flds->type = rtx_tp;
      break;

    default:
      note_flds->name = "rt_int";
      note_flds->type = scalar_tp;
      break;
    }
      }
    new_structure ("rtx_def_note_subunion", 1, &lexer_line, note_flds, NULL);
  }

  note_union_tp = find_structure ("rtx_def_note_subunion", 1);

  for (i = 0; i < NUM_RTX_CODE; i++)
    {
      pair_p old_flds = flds;
      pair_p subfields = NULL;
      size_t aindex, nmindex;
      const char *sname;
      char *ftag;

      for (aindex = 0; aindex < strlen (rtx_format[i]); aindex++)
  {
    pair_p old_subf = subfields;
    type_p t;
    const char *subname;

    switch (rtx_format[i][aindex])
      {
      case '*':
      case 'i':
      case 'n':
      case 'w':
        t = scalar_tp;
        subname = "rt_int";
        break;

      case '0':
        if (i == MEM && aindex == 1)
    t = mem_attrs_tp, subname = "rt_mem";
        else if (i == JUMP_INSN && aindex == 9)
    t = rtx_tp, subname = "rt_rtx";
        else if (i == CODE_LABEL && aindex == 4)
    t = scalar_tp, subname = "rt_int";
        else if (i == CODE_LABEL && aindex == 5)
    t = rtx_tp, subname = "rt_rtx";
        else if (i == LABEL_REF
           && (aindex == 1 || aindex == 2))
    t = rtx_tp, subname = "rt_rtx";
        else if (i == NOTE && aindex == 4)
    t = note_union_tp, subname = "";
        else if (i == NOTE && aindex >= 7)
    t = scalar_tp, subname = "rt_int";
        else if (i == ADDR_DIFF_VEC && aindex == 4)
    t = scalar_tp, subname = "rt_int";
        else if (i == VALUE && aindex == 0)
    t = scalar_tp, subname = "rt_int";
        else if (i == REG && aindex == 1)
    t = scalar_tp, subname = "rt_int";
        else if (i == REG && aindex == 2)
    t = reg_attrs_tp, subname = "rt_reg";
        else if (i == SCRATCH && aindex == 0)
    t = scalar_tp, subname = "rt_int";
        else if (i == SYMBOL_REF && aindex == 1)
    t = scalar_tp, subname = "rt_int";
        else if (i == SYMBOL_REF && aindex == 2)
    t = tree_tp, subname = "rt_tree";
        else if (i == BARRIER && aindex >= 3)
    t = scalar_tp, subname = "rt_int";
        else
    {
      error_at_line (&lexer_line,
      "rtx type `%s' has `0' in position %lu, can't handle",
         rtx_name[i], (unsigned long) aindex);
      t = &string_type;
      subname = "rt_int";
    }
        break;

      case 's':
      case 'S':
      case 'T':
        t = &string_type;
        subname = "rt_str";
        break;

      case 'e':
      case 'u':
        t = rtx_tp;
        subname = "rt_rtx";
        break;

      case 'E':
      case 'V':
        t = rtvec_tp;
        subname = "rt_rtvec";
        break;

      case 't':
        t = tree_tp;
        subname = "rt_tree";
        break;

      case 'b':
        t = bitmap_tp;
        subname = "rt_bit";
        break;

      case 'B':
        t = basic_block_tp;
        subname = "rt_bb";
        break;

      default:
        error_at_line (&lexer_line,
         "rtx type `%s' has `%c' in position %lu, can't handle",
           rtx_name[i], rtx_format[i][aindex],
           (unsigned long)aindex);
        t = &string_type;
        subname = "rt_int";
        break;
      }

    subfields = XNEW (struct pair);
    subfields->next = old_subf;
    subfields->type = t;
    subfields->name = xasprintf (".fld[%lu].%s", (unsigned long)aindex,
               subname);
    subfields->line.file = __FILE__;
    subfields->line.line = __LINE__;
    if (t == note_union_tp)
      {
        subfields->opt = XNEW (struct options);
        subfields->opt->next = nodot;
        subfields->opt->name = "desc";
        subfields->opt->info = "NOTE_LINE_NUMBER (&%0)";
      }
    else if (t == basic_block_tp)
      {
        /* We don't presently GC basic block structures...  */
        subfields->opt = XNEW (struct options);
        subfields->opt->next = nodot;
        subfields->opt->name = "skip";
        subfields->opt->info = NULL;
      }
    else
      subfields->opt = nodot;
  }

      flds = XNEW (struct pair);
      flds->next = old_flds;
      flds->name = "";
      sname = xasprintf ("rtx_def_%s", rtx_name[i]);
      new_structure (sname, 0, &lexer_line, subfields, NULL);
      flds->type = find_structure (sname, 0);
      flds->line.file = __FILE__;
      flds->line.line = __LINE__;
      flds->opt = XNEW (struct options);
      flds->opt->next = nodot;
      flds->opt->name = "tag";
      ftag = xstrdup (rtx_name[i]);
      for (nmindex = 0; nmindex < strlen (ftag); nmindex++)
  ftag[nmindex] = TOUPPER (ftag[nmindex]);
      flds->opt->info = ftag;
    }

  new_structure ("rtx_def_subunion", 1, &lexer_line, flds, nodot);
  return find_structure ("rtx_def_subunion", 1);
}

/* Handle `special("tree_exp")'.  This is a special case for
   field `operands' of struct tree_exp, which although it claims to contain
   pointers to trees, actually sometimes contains pointers to RTL too.
   Passed T, the old type of the field, and OPT its options.  Returns
   a new type for the field.  */

static type_p
adjust_field_tree_exp (type_p t, options_p opt ATTRIBUTE_UNUSED)
{
  pair_p flds;
  options_p nodot;

  if (t->kind != TYPE_ARRAY)
    {
      error_at_line (&lexer_line,
         "special `tree_exp' must be applied to an array");
      return &string_type;
    }

  nodot = XNEW (struct options);
  nodot->next = NULL;
  nodot->name = "dot";
  nodot->info = "";

  flds = XNEW (struct pair);
  flds->next = NULL;
  flds->name = "";
  flds->type = t;
  flds->line.file = __FILE__;
  flds->line.line = __LINE__;
  flds->opt = XNEW (struct options);
  flds->opt->next = nodot;
  flds->opt->name = "length";
  flds->opt->info = "TREE_CODE_LENGTH (TREE_CODE ((tree) &%0))";
  {
    options_p oldopt = flds->opt;
    flds->opt = XNEW (struct options);
    flds->opt->next = oldopt;
    flds->opt->name = "default";
    flds->opt->info = "";
  }

  new_structure ("tree_exp_subunion", 1, &lexer_line, flds, nodot);
  return find_structure ("tree_exp_subunion", 1);
}

/* Perform any special processing on a type T, about to become the type
   of a field.  Return the appropriate type for the field.
   At present:
   - Converts pointer-to-char, with no length parameter, to TYPE_STRING;
   - Similarly for arrays of pointer-to-char;
   - Converts structures for which a parameter is provided to
     TYPE_PARAM_STRUCT;
   - Handles "special" options.
*/

type_p
adjust_field_type (type_p t, options_p opt)
{
  int length_p = 0;
  const int pointer_p = t->kind == TYPE_POINTER;
  type_p params[NUM_PARAM];
  int params_p = 0;
  int i;

  for (i = 0; i < NUM_PARAM; i++)
    params[i] = NULL;

  for (; opt; opt = opt->next)
    if (strcmp (opt->name, "length") == 0)
      length_p = 1;
    else if (strcmp (opt->name, "param_is") == 0
       || (strncmp (opt->name, "param", 5) == 0
     && ISDIGIT (opt->name[5])
     && strcmp (opt->name + 6, "_is") == 0))
      {
  int num = ISDIGIT (opt->name[5]) ? opt->name[5] - '0' : 0;

  if (! UNION_OR_STRUCT_P (t)
      && (t->kind != TYPE_POINTER || ! UNION_OR_STRUCT_P (t->u.p)))
    {
      error_at_line (&lexer_line,
   "option `%s' may only be applied to structures or structure pointers",
         opt->name);
      return t;
    }

  params_p = 1;
  if (params[num] != NULL)
    error_at_line (&lexer_line, "duplicate `%s' option", opt->name);
  if (! ISDIGIT (opt->name[5]))
    params[num] = create_pointer ((type_p) opt->info);
  else
    params[num] = (type_p) opt->info;
      }
    else if (strcmp (opt->name, "special") == 0)
      {
  const char *special_name = opt->info;
  if (strcmp (special_name, "tree_exp") == 0)
    t = adjust_field_tree_exp (t, opt);
  else if (strcmp (special_name, "rtx_def") == 0)
    t = adjust_field_rtx_def (t, opt);
  else
    error_at_line (&lexer_line, "unknown special `%s'", special_name);
      }

  if (params_p)
    {
      type_p realt;

      if (pointer_p)
  t = t->u.p;
      realt = find_param_structure (t, params);
      t = pointer_p ? create_pointer (realt) : realt;
    }

  if (! length_p
      && pointer_p
      && t->u.p->kind == TYPE_SCALAR
      && (strcmp (t->u.p->u.sc, "char") == 0
    || strcmp (t->u.p->u.sc, "unsigned char") == 0))
    return &string_type;
  if (t->kind == TYPE_ARRAY && t->u.a.p->kind == TYPE_POINTER
      && t->u.a.p->u.p->kind == TYPE_SCALAR
      && (strcmp (t->u.a.p->u.p->u.sc, "char") == 0
    || strcmp (t->u.a.p->u.p->u.sc, "unsigned char") == 0))
    return create_array (&string_type, t->u.a.len);

  return t;
}

/* Create a union for YYSTYPE, as yacc would do it, given a fieldlist FIELDS
   and information about the correspondence between token types and fields
   in TYPEINFO.  POS is used for error messages.  */

void
note_yacc_type (options_p o, pair_p fields, pair_p typeinfo,
    struct fileloc *pos)
{
  pair_p p;
  pair_p *p_p;

  for (p = typeinfo; p; p = p->next)
    {
      pair_p m;

      if (p->name == NULL)
  continue;

      if (p->type == (type_p) 1)
  {
    pair_p pp;
    int ok = 0;

    for (pp = typeinfo; pp; pp = pp->next)
      if (pp->type != (type_p) 1
    && strcmp (pp->opt->info, p->opt->info) == 0)
        {
    ok = 1;
    break;
        }
    if (! ok)
      continue;
  }

      for (m = fields; m; m = m->next)
  if (strcmp (m->name, p->name) == 0)
    p->type = m->type;
      if (p->type == NULL)
  {
    error_at_line (&p->line,
       "couldn't match fieldname `%s'", p->name);
    p->name = NULL;
  }
    }

  p_p = &typeinfo;
  while (*p_p)
    {
      pair_p p = *p_p;

      if (p->name == NULL
    || p->type == (type_p) 1)
  *p_p = p->next;
      else
  p_p = &p->next;
    }

  new_structure ("yy_union", 1, pos, typeinfo, o);
  do_typedef ("YYSTYPE", find_structure ("yy_union", 1), pos);
}

static void process_gc_options (options_p, enum gc_used_enum,
        int *, int *, int *, type_p *);
static void set_gc_used_type (type_p, enum gc_used_enum, type_p *);
static void set_gc_used (pair_p);

/* Handle OPT for set_gc_used_type.  */

static void
process_gc_options (options_p opt, enum gc_used_enum level, int *maybe_undef,
        int *pass_param, int *length, type_p *nested_ptr)
{
  options_p o;
  for (o = opt; o; o = o->next)
    if (strcmp (o->name, "ptr_alias") == 0 && level == GC_POINTED_TO)
      set_gc_used_type ((type_p) o->info, GC_POINTED_TO, NULL);
    else if (strcmp (o->name, "maybe_undef") == 0)
      *maybe_undef = 1;
    else if (strcmp (o->name, "use_params") == 0)
      *pass_param = 1;
    else if (strcmp (o->name, "length") == 0)
      *length = 1;
    else if (strcmp (o->name, "nested_ptr") == 0)
      *nested_ptr = ((const struct nested_ptr_data *) o->info)->type;
}

/* Set the gc_used field of T to LEVEL, and handle the types it references.  */

static void
set_gc_used_type (type_p t, enum gc_used_enum level, type_p param[NUM_PARAM])
{
  if (t->gc_used >= level)
    return;

  t->gc_used = level;

  switch (t->kind)
    {
    case TYPE_STRUCT:
    case TYPE_UNION:
      {
  pair_p f;
  int dummy;
  type_p dummy2;

  process_gc_options (t->u.s.opt, level, &dummy, &dummy, &dummy,
          &dummy2);

  for (f = t->u.s.fields; f; f = f->next)
    {
      int maybe_undef = 0;
      int pass_param = 0;
      int length = 0;
      type_p nested_ptr = NULL;
      process_gc_options (f->opt, level, &maybe_undef, &pass_param,
        &length, &nested_ptr);

      if (nested_ptr && f->type->kind == TYPE_POINTER)
        set_gc_used_type (nested_ptr, GC_POINTED_TO, 
        pass_param ? param : NULL);
      else if (length && f->type->kind == TYPE_POINTER)
        set_gc_used_type (f->type->u.p, GC_USED, NULL);
      else if (maybe_undef && f->type->kind == TYPE_POINTER)
        set_gc_used_type (f->type->u.p, GC_MAYBE_POINTED_TO, NULL);
      else if (pass_param && f->type->kind == TYPE_POINTER && param)
        set_gc_used_type (find_param_structure (f->type->u.p, param),
        GC_POINTED_TO, NULL);
      else
        set_gc_used_type (f->type, GC_USED, pass_param ? param : NULL);
    }
  break;
      }

    case TYPE_POINTER:
      set_gc_used_type (t->u.p, GC_POINTED_TO, NULL);
      break;

    case TYPE_ARRAY:
      set_gc_used_type (t->u.a.p, GC_USED, param);
      break;

    case TYPE_LANG_STRUCT:
      for (t = t->u.s.lang_struct; t; t = t->next)
  set_gc_used_type (t, level, param);
      break;

    case TYPE_PARAM_STRUCT:
      {
  int i;
  for (i = 0; i < NUM_PARAM; i++)
    if (t->u.param_struct.param[i] != 0)
      set_gc_used_type (t->u.param_struct.param[i], GC_USED, NULL);
      }
      if (t->u.param_struct.stru->gc_used == GC_POINTED_TO)
  level = GC_POINTED_TO;
      else
  level = GC_USED;
      t->u.param_struct.stru->gc_used = GC_UNUSED;
      set_gc_used_type (t->u.param_struct.stru, level,
      t->u.param_struct.param);
      break;

    default:
      break;
    }
}

/* Set the gc_used fields of all the types pointed to by VARIABLES.  */

static void
set_gc_used (pair_p variables)
{
  pair_p p;
  for (p = variables; p; p = p->next)
    set_gc_used_type (p->type, GC_USED, NULL);
}

/* File mapping routines.  For each input file, there is one output .c file
   (but some output files have many input files), and there is one .h file
   for the whole build.  */

/* The list of output files.  */
static outf_p output_files;

/* The output header file that is included into pretty much every
   source file.  */
static outf_p header_file;

/* Number of files specified in gtfiles.  */
#define NUM_GT_FILES (ARRAY_SIZE (all_files) - 1)

/* Number of files in the language files array.  */
#define NUM_LANG_FILES (ARRAY_SIZE (lang_files) - 1)

/* Length of srcdir name.  */
static int srcdir_len = 0;

#define NUM_BASE_FILES (ARRAY_SIZE (lang_dir_names) - 1)
outf_p base_files[NUM_BASE_FILES];

static outf_p create_file (const char *, const char *);
static const char * get_file_basename (const char *);

/* Create and return an outf_p for a new file for NAME, to be called
   ONAME.  */

static outf_p
create_file (const char *name, const char *oname)
{
  static const char *const hdr[] = {
    "   Copyright (C) 2004 Free Software Foundation, Inc.\n",
    "\n",
    "This file is part of GCC.\n",
    "\n",
    "GCC is free software; you can redistribute it and/or modify it under\n",
    "the terms of the GNU General Public License as published by the Free\n",
    "Software Foundation; either version 2, or (at your option) any later\n",
    "version.\n",
    "\n",
    "GCC is distributed in the hope that it will be useful, but WITHOUT ANY\n",
    "WARRANTY; without even the implied warranty of MERCHANTABILITY or\n",
    "FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License\n",
    "for more details.\n",
    "\n",
    "You should have received a copy of the GNU General Public License\n",
    "along with GCC; see the file COPYING.  If not, write to the Free\n",
    "Software Foundation, 59 Temple Place - Suite 330, Boston, MA\n",
    "02111-1307, USA.  */\n",
    "\n",
    "/* This file is machine generated.  Do not edit.  */\n"
  };
  outf_p f;
  size_t i;

  f = XCNEW (struct outf);
  f->next = output_files;
  f->name = oname;
  output_files = f;

  oprintf (f, "/* Type information for %s.\n", name);
  for (i = 0; i < ARRAY_SIZE (hdr); i++)
    oprintf (f, "%s", hdr[i]);
  return f;
}

/* Print, like fprintf, to O.  */
void
oprintf (outf_p o, const char *format, ...)
{
  char *s;
  size_t slength;
  va_list ap;

  va_start (ap, format);
  slength = xvasprintf (&s, format, ap);

  if (o->bufused + slength > o->buflength)
    {
      size_t new_len = o->buflength;
      if (new_len == 0)
  new_len = 1024;
      do {
  new_len *= 2;
      } while (o->bufused + slength >= new_len);
      o->buf = XRESIZEVEC (char, o->buf, new_len);
      o->buflength = new_len;
    }
  memcpy (o->buf + o->bufused, s, slength);
  o->bufused += slength;
  free (s);
  va_end (ap);
}

/* Open the global header file and the language-specific header files.  */

static void
open_base_files (void)
{
  size_t i;

  header_file = create_file ("GCC", "gtype-desc.h");

  for (i = 0; i < NUM_BASE_FILES; i++)
    base_files[i] = create_file (lang_dir_names[i],
         xasprintf ("gtype-%s.h", lang_dir_names[i]));

  /* gtype-desc.c is a little special, so we create it here.  */
  {
    /* The order of files here matters very much.  */
    static const char *const ifiles [] = {
      "config.h", "system.h", "coretypes.h", "tm.h", "varray.h", 
      "hashtab.h", "splay-tree.h",  "obstack.h", "bitmap.h", "input.h",
      "tree.h", "rtl.h", "function.h", "insn-config.h", "expr.h",
      "hard-reg-set.h", "basic-block.h", "cselib.h", "insn-addr.h",
      "optabs.h", "libfuncs.h", "debug.h", "ggc.h", "cgraph.h",
      "tree-flow.h", "reload.h", "cpp-id-data.h", "tree-chrec.h",
      NULL
    };
    const char *const *ifp;
    outf_p gtype_desc_c;

    gtype_desc_c = create_file ("GCC", "gtype-desc.c");
    for (ifp = ifiles; *ifp; ifp++)
      oprintf (gtype_desc_c, "#include \"%s\"\n", *ifp);
  }
}

/* Determine the pathname to F relative to $(srcdir).  */

static const char *
get_file_basename (const char *f)
{
  const char *basename;
  unsigned i;

  basename = strrchr (f, '/');

  if (!basename)
    return f;

  basename++;

  for (i = 1; i < NUM_BASE_FILES; i++)
    {
      const char * s1;
      const char * s2;
      int l1;
      int l2;
      s1 = basename - strlen (lang_dir_names [i]) - 1;
      s2 = lang_dir_names [i];
      l1 = strlen (s1);
      l2 = strlen (s2);
      if (l1 >= l2 && IS_DIR_SEPARATOR (s1[-1]) && !memcmp (s1, s2, l2))
        {
          basename -= l2 + 1;
          if ((basename - f - 1) != srcdir_len)
      fatal ("filename `%s' should be preceded by $srcdir", f);
          break;
        }
    }

  return basename;
}

/* Return a bitmap which has bit `1 << BASE_FILE_<lang>' set iff
   INPUT_FILE is used by <lang>.

   This function should be written to assume that a file _is_ used
   if the situation is unclear.  If it wrongly assumes a file _is_ used,
   a linker error will result.  If it wrongly assumes a file _is not_ used,
   some GC roots may be missed, which is a much harder-to-debug problem.  */

unsigned
get_base_file_bitmap (const char *input_file)
{
  const char *basename = get_file_basename (input_file);
  const char *slashpos = strchr (basename, '/');
  unsigned j;
  unsigned k;
  unsigned bitmap;

  /* If the file resides in a language subdirectory (e.g., 'cp'), assume that
     it belongs to the corresponding language.  The file may belong to other
     languages as well (which is checked for below).  */

  if (slashpos)
    {
      size_t i;
      for (i = 1; i < NUM_BASE_FILES; i++)
  if ((size_t)(slashpos - basename) == strlen (lang_dir_names [i])
      && memcmp (basename, lang_dir_names[i], strlen (lang_dir_names[i])) == 0)
          {
            /* It's in a language directory, set that language.  */
            bitmap = 1 << i;
          }
    }

  /* If it's in any config-lang.in, then set for the languages
     specified.  */

  bitmap = 0;

  for (j = 0; j < NUM_LANG_FILES; j++)
    {
      if (!strcmp(input_file, lang_files[j]))
        {
          for (k = 0; k < NUM_BASE_FILES; k++)
            {
              if (!strcmp(lang_dir_names[k], langs_for_lang_files[j]))
                bitmap |= (1 << k);
            }
        }
    }

  /* Otherwise, set all languages.  */
  if (!bitmap)
    bitmap = (1 << NUM_BASE_FILES) - 1;

  return bitmap;
}

/* An output file, suitable for definitions, that can see declarations
   made in INPUT_FILE and is linked into every language that uses
   INPUT_FILE.  */

outf_p
get_output_file_with_visibility (const char *input_file)
{
  outf_p r;
  size_t len;
  const char *basename;
  const char *for_name;
  const char *output_name;

  /* This can happen when we need a file with visibility on a
     structure that we've never seen.  We have to just hope that it's
     globally visible.  */
  if (input_file == NULL)
    input_file = "system.h";

  /* Determine the output file name.  */
  basename = get_file_basename (input_file);

  len = strlen (basename);
  if ((len > 2 && memcmp (basename+len-2, ".c", 2) == 0)
      || (len > 2 && memcmp (basename+len-2, ".y", 2) == 0)
      || (len > 3 && memcmp (basename+len-3, ".in", 3) == 0))
    {
      char *s;

      output_name = s = xasprintf ("gt-%s", basename);
      for (; *s != '.'; s++)
  if (! ISALNUM (*s) && *s != '-')
    *s = '-';
      memcpy (s, ".h", sizeof (".h"));
      for_name = basename;
    }
  /* Some headers get used by more than one front-end; hence, it
     would be inappropriate to spew them out to a single gtype-<lang>.h
     (and gengtype doesn't know how to direct spewage into multiple
     gtype-<lang>.h headers at this time).  Instead, we pair up these
     headers with source files (and their special purpose gt-*.h headers).  */
  else if (strcmp (basename, "c-common.h") == 0)
    output_name = "gt-c-common.h", for_name = "c-common.c";
  else if (strcmp (basename, "c-tree.h") == 0)
    output_name = "gt-c-decl.h", for_name = "c-decl.c";
  else if (strncmp (basename, "objc", 4) == 0 && IS_DIR_SEPARATOR (basename[4])
     && strcmp (basename + 5, "objc-act.h") == 0)
    output_name = "gt-objc-objc-act.h", for_name = "objc/objc-act.c";
  else 
    {
      size_t i;

      for (i = 0; i < NUM_BASE_FILES; i++)
  if (memcmp (basename, lang_dir_names[i], strlen (lang_dir_names[i])) == 0
      && basename[strlen(lang_dir_names[i])] == '/')
    return base_files[i];

      output_name = "gtype-desc.c";
      for_name = NULL;
    }

  /* Look through to see if we've ever seen this output filename before.  */
  for (r = output_files; r; r = r->next)
    if (strcmp (r->name, output_name) == 0)
      return r;

  /* If not, create it.  */
  r = create_file (for_name, output_name);

  return r;
}

/* The name of an output file, suitable for definitions, that can see
   declarations made in INPUT_FILE and is linked into every language
   that uses INPUT_FILE.  */

const char *
get_output_file_name (const char *input_file)
{
  return get_output_file_with_visibility (input_file)->name;
}

/* Copy the output to its final destination,
   but don't unnecessarily change modification times.  */

static void
close_output_files (void)
{
  outf_p of;

  for (of = output_files; of; of = of->next)
    {
      FILE * newfile;

      newfile = fopen (of->name, "r");
      if (newfile != NULL )
  {
    int no_write_p;
    size_t i;

    for (i = 0; i < of->bufused; i++)
      {
        int ch;
        ch = fgetc (newfile);
        if (ch == EOF || ch != (unsigned char) of->buf[i])
    break;
      }
    no_write_p = i == of->bufused && fgetc (newfile) == EOF;
    fclose (newfile);

    if (no_write_p)
      continue;
  }

      newfile = fopen (of->name, "w");
      if (newfile == NULL)
  {
    perror ("opening output file");
    exit (1);
  }
      if (fwrite (of->buf, 1, of->bufused, newfile) != of->bufused)
  {
    perror ("writing output file");
    exit (1);
  }
      if (fclose (newfile) != 0)
  {
    perror ("closing output file");
    exit (1);
  }
    }
}

struct flist {
  struct flist *next;
  int started_p;
  const char *name;
  outf_p f;
};

struct walk_type_data;

/* For scalars and strings, given the item in 'val'.
   For structures, given a pointer to the item in 'val'.
   For misc. pointers, given the item in 'val'.
*/
typedef void (*process_field_fn)
     (type_p f, const struct walk_type_data *p);
typedef void (*func_name_fn)
     (type_p s, const struct walk_type_data *p);

/* Parameters for write_types.  */

struct write_types_data
{
  const char *prefix;
  const char *param_prefix;
  const char *subfield_marker_routine;
  const char *marker_routine;
  const char *reorder_note_routine;
  const char *comment;
};

static void output_escaped_param (struct walk_type_data *d,
          const char *, const char *);
static void output_mangled_typename (outf_p, type_p);
static void walk_type (type_p t, struct walk_type_data *d);
static void write_func_for_structure
     (type_p orig_s, type_p s, type_p * param,
      const struct write_types_data *wtd);
static void write_types_process_field
     (type_p f, const struct walk_type_data *d);
static void write_types (type_p structures,
       type_p param_structs,
       const struct write_types_data *wtd);
static void write_types_local_process_field
     (type_p f, const struct walk_type_data *d);
static void write_local_func_for_structure
     (type_p orig_s, type_p s, type_p * param);
static void write_local (type_p structures,
       type_p param_structs);
static void write_enum_defn (type_p structures, type_p param_structs);
static int contains_scalar_p (type_p t);
static void put_mangled_filename (outf_p , const char *);
static void finish_root_table (struct flist *flp, const char *pfx,
             const char *tname, const char *lastname,
             const char *name);
static void write_root (outf_p , pair_p, type_p, const char *, int,
      struct fileloc *, const char *);
static void write_array (outf_p f, pair_p v,
       const struct write_types_data *wtd);
static void write_roots (pair_p);

/* Parameters for walk_type.  */

struct walk_type_data
{
  process_field_fn process_field;
  const void *cookie;
  outf_p of;
  options_p opt;
  const char *val;
  const char *prev_val[4];
  int indent;
  int counter;
  struct fileloc *line;
  lang_bitmap bitmap;
  type_p *param;
  int used_length;
  type_p orig_s;
  const char *reorder_fn;
  bool needs_cast_p;
  bool fn_wants_lvalue;
};

/* Print a mangled name representing T to OF.  */

static void
output_mangled_typename (outf_p of, type_p t)
{
  if (t == NULL)
    oprintf (of, "Z");
  else switch (t->kind)
    {
    case TYPE_POINTER:
      oprintf (of, "P");
      output_mangled_typename (of, t->u.p);
      break;
    case TYPE_SCALAR:
      oprintf (of, "I");
      break;
    case TYPE_STRING:
      oprintf (of, "S");
      break;
    case TYPE_STRUCT:
    case TYPE_UNION:
    case TYPE_LANG_STRUCT:
      oprintf (of, "%lu%s", (unsigned long) strlen (t->u.s.tag), t->u.s.tag);
      break;
    case TYPE_PARAM_STRUCT:
      {
  int i;
  for (i = 0; i < NUM_PARAM; i++)
    if (t->u.param_struct.param[i] != NULL)
      output_mangled_typename (of, t->u.param_struct.param[i]);
  output_mangled_typename (of, t->u.param_struct.stru);
      }
      break;
    case TYPE_ARRAY:
      gcc_unreachable ();
    }
}

/* Print PARAM to D->OF processing escapes.  D->VAL references the
   current object, D->PREV_VAL the object containing the current
   object, ONAME is the name of the option and D->LINE is used to
   print error messages.  */

static void
output_escaped_param (struct walk_type_data *d, const char *param,
          const char *oname)
{
  const char *p;

  for (p = param; *p; p++)
    if (*p != '%')
      oprintf (d->of, "%c", *p);
    else switch (*++p)
      {
      case 'h':
  oprintf (d->of, "(%s)", d->prev_val[2]);
  break;
      case '0':
  oprintf (d->of, "(%s)", d->prev_val[0]);
  break;
      case '1':
  oprintf (d->of, "(%s)", d->prev_val[1]);
  break;
      case 'a':
  {
    const char *pp = d->val + strlen (d->val);
    while (pp[-1] == ']')
      while (*pp != '[')
        pp--;
    oprintf (d->of, "%s", pp);
  }
  break;
      default:
  error_at_line (d->line, "`%s' option contains bad escape %c%c",
           oname, '%', *p);
      }
}

/* Call D->PROCESS_FIELD for every field (or subfield) of D->VAL,
   which is of type T.  Write code to D->OF to constrain execution (at
   the point that D->PROCESS_FIELD is called) to the appropriate
   cases.  Call D->PROCESS_FIELD on subobjects before calling it on
   pointers to those objects.  D->PREV_VAL lists the objects
   containing the current object, D->OPT is a list of options to
   apply, D->INDENT is the current indentation level, D->LINE is used
   to print error messages, D->BITMAP indicates which languages to
   print the structure for, and D->PARAM is the current parameter
   (from an enclosing param_is option).  */

static void
walk_type (type_p t, struct walk_type_data *d)
{
  const char *length = NULL;
  const char *desc = NULL;
  int maybe_undef_p = 0;
  int use_param_num = -1;
  int use_params_p = 0;
  options_p oo;
  const struct nested_ptr_data *nested_ptr_d = NULL;

  d->needs_cast_p = false;
  for (oo = d->opt; oo; oo = oo->next)
    if (strcmp (oo->name, "length") == 0)
      length = oo->info;
    else if (strcmp (oo->name, "maybe_undef") == 0)
      maybe_undef_p = 1;
    else if (strncmp (oo->name, "use_param", 9) == 0
       && (oo->name[9] == '\0' || ISDIGIT (oo->name[9])))
      use_param_num = oo->name[9] == '\0' ? 0 : oo->name[9] - '0';
    else if (strcmp (oo->name, "use_params") == 0)
      use_params_p = 1;
    else if (strcmp (oo->name, "desc") == 0)
      desc = oo->info;
    else if (strcmp (oo->name, "nested_ptr") == 0)
      nested_ptr_d = (const struct nested_ptr_data *) oo->info;
    else if (strcmp (oo->name, "dot") == 0)
      ;
    else if (strcmp (oo->name, "tag") == 0)
      ;
    else if (strcmp (oo->name, "special") == 0)
      ;
    else if (strcmp (oo->name, "skip") == 0)
      ;
    else if (strcmp (oo->name, "default") == 0)
      ;
    else if (strcmp (oo->name, "descbits") == 0)
      ;
    else if (strcmp (oo->name, "param_is") == 0)
      ;
    else if (strncmp (oo->name, "param", 5) == 0
       && ISDIGIT (oo->name[5])
       && strcmp (oo->name + 6, "_is") == 0)
      ;
    else if (strcmp (oo->name, "chain_next") == 0)
      ;
    else if (strcmp (oo->name, "chain_prev") == 0)
      ;
    else if (strcmp (oo->name, "reorder") == 0)
      ;
    else
      error_at_line (d->line, "unknown option `%s'\n", oo->name);

  if (d->used_length)
    length = NULL;

  if (use_params_p)
    {
      int pointer_p = t->kind == TYPE_POINTER;

      if (pointer_p)
  t = t->u.p;
      if (! UNION_OR_STRUCT_P (t))
  error_at_line (d->line, "`use_params' option on unimplemented type");
      else
  t = find_param_structure (t, d->param);
      if (pointer_p)
  t = create_pointer (t);
    }

  if (use_param_num != -1)
    {
      if (d->param != NULL && d->param[use_param_num] != NULL)
  {
    type_p nt = d->param[use_param_num];

    if (t->kind == TYPE_ARRAY)
      nt = create_array (nt, t->u.a.len);
    else if (length != NULL && t->kind == TYPE_POINTER)
      nt = create_pointer (nt);
    d->needs_cast_p = (t->kind != TYPE_POINTER
           && (nt->kind == TYPE_POINTER
         || nt->kind == TYPE_STRING));
    t = nt;
  }
      else
  error_at_line (d->line, "no parameter defined for `%s'",
           d->val);
    }

  if (maybe_undef_p
      && (t->kind != TYPE_POINTER || ! UNION_OR_STRUCT_P (t->u.p)))
    {
      error_at_line (d->line,
         "field `%s' has invalid option `maybe_undef_p'\n",
         d->val);
      return;
    }

  switch (t->kind)
    {
    case TYPE_SCALAR:
    case TYPE_STRING:
      d->process_field (t, d);
      break;

    case TYPE_POINTER:
      {
  if (maybe_undef_p
      && t->u.p->u.s.line.file == NULL)
    {
      oprintf (d->of, "%*sgcc_assert (!%s);\n", d->indent, "", d->val);
      break;
    }

  if (! length)
    {
      if (! UNION_OR_STRUCT_P (t->u.p)
    && t->u.p->kind != TYPE_PARAM_STRUCT)
        {
    error_at_line (d->line,
             "field `%s' is pointer to unimplemented type",
             d->val);
    break;
        }

      if (nested_ptr_d)
        {
    const char *oldprevval2 = d->prev_val[2];

    if (! UNION_OR_STRUCT_P (nested_ptr_d->type))
      {
        error_at_line (d->line,
           "field `%s' has invalid "
           "option `nested_ptr'\n",
           d->val);
        return;
      }

    d->prev_val[2] = d->val;
    oprintf (d->of, "%*s{\n", d->indent, "");
    d->indent += 2;
    d->val = xasprintf ("x%d", d->counter++);
    oprintf (d->of, "%*s%s %s * %s%s =\n", d->indent, "",
       (nested_ptr_d->type->kind == TYPE_UNION 
        ? "union" : "struct"), 
       nested_ptr_d->type->u.s.tag, 
       d->fn_wants_lvalue ? "" : "const ",
       d->val);
    oprintf (d->of, "%*s", d->indent + 2, "");
    output_escaped_param (d, nested_ptr_d->convert_from,
              "nested_ptr");
    oprintf (d->of, ";\n");

    d->process_field (nested_ptr_d->type, d);

    if (d->fn_wants_lvalue)
      {
        oprintf (d->of, "%*s%s = ", d->indent, "",
           d->prev_val[2]);
        d->prev_val[2] = d->val;
        output_escaped_param (d, nested_ptr_d->convert_to,
            "nested_ptr");
        oprintf (d->of, ";\n");
      }

    d->indent -= 2;
    oprintf (d->of, "%*s}\n", d->indent, "");
    d->val = d->prev_val[2];
    d->prev_val[2] = oldprevval2;
        }
      else
        d->process_field (t->u.p, d);
    }
  else
    {
      int loopcounter = d->counter++;
      const char *oldval = d->val;
      const char *oldprevval3 = d->prev_val[3];
      char *newval;

      oprintf (d->of, "%*sif (%s != NULL) {\n", d->indent, "", d->val);
      d->indent += 2;
      oprintf (d->of, "%*ssize_t i%d;\n", d->indent, "", loopcounter);
      oprintf (d->of, "%*sfor (i%d = 0; i%d != (size_t)(", d->indent, "",
         loopcounter, loopcounter);
      output_escaped_param (d, length, "length");
      oprintf (d->of, "); i%d++) {\n", loopcounter);
      d->indent += 2;
      d->val = newval = xasprintf ("%s[i%d]", oldval, loopcounter);
      d->used_length = 1;
      d->prev_val[3] = oldval;
      walk_type (t->u.p, d);
      free (newval);
      d->val = oldval;
      d->prev_val[3] = oldprevval3;
      d->used_length = 0;
      d->indent -= 2;
      oprintf (d->of, "%*s}\n", d->indent, "");
      d->process_field(t, d);
      d->indent -= 2;
      oprintf (d->of, "%*s}\n", d->indent, "");
    }
      }
      break;

    case TYPE_ARRAY:
      {
  int loopcounter = d->counter++;
  const char *oldval = d->val;
  char *newval;

  /* If it's an array of scalars, we optimize by not generating
     any code.  */
  if (t->u.a.p->kind == TYPE_SCALAR)
    break;

  oprintf (d->of, "%*s{\n", d->indent, "");
  d->indent += 2;
  oprintf (d->of, "%*ssize_t i%d;\n", d->indent, "", loopcounter);
  oprintf (d->of, "%*sfor (i%d = 0; i%d != (size_t)(", d->indent, "",
     loopcounter, loopcounter);
  if (length)
    output_escaped_param (d, length, "length");
  else
    oprintf (d->of, "%s", t->u.a.len);
  oprintf (d->of, "); i%d++) {\n", loopcounter);
  d->indent += 2;
  d->val = newval = xasprintf ("%s[i%d]", oldval, loopcounter);
  d->used_length = 1;
  walk_type (t->u.a.p, d);
  free (newval);
  d->used_length = 0;
  d->val = oldval;
  d->indent -= 2;
  oprintf (d->of, "%*s}\n", d->indent, "");
  d->indent -= 2;
  oprintf (d->of, "%*s}\n", d->indent, "");
      }
      break;

    case TYPE_STRUCT:
    case TYPE_UNION:
      {
  pair_p f;
  const char *oldval = d->val;
  const char *oldprevval1 = d->prev_val[1];
  const char *oldprevval2 = d->prev_val[2];
  const int union_p = t->kind == TYPE_UNION;
  int seen_default_p = 0;
  options_p o;

  if (! t->u.s.line.file)
    error_at_line (d->line, "incomplete structure `%s'", t->u.s.tag);

  if ((d->bitmap & t->u.s.bitmap) != d->bitmap)
    {
      error_at_line (d->line,
         "structure `%s' defined for mismatching languages",
         t->u.s.tag);
      error_at_line (&t->u.s.line, "one structure defined here");
    }

  /* Some things may also be defined in the structure's options.  */
  for (o = t->u.s.opt; o; o = o->next)
    if (! desc && strcmp (o->name, "desc") == 0)
      desc = o->info;

  d->prev_val[2] = oldval;
  d->prev_val[1] = oldprevval2;
  if (union_p)
    {
      if (desc == NULL)
        {
    error_at_line (d->line, "missing `desc' option for union `%s'",
             t->u.s.tag);
    desc = "1";
        }
      oprintf (d->of, "%*sswitch (", d->indent, "");
      output_escaped_param (d, desc, "desc");
      oprintf (d->of, ")\n");
      d->indent += 2;
      oprintf (d->of, "%*s{\n", d->indent, "");
    }
  for (f = t->u.s.fields; f; f = f->next)
    {
      options_p oo;
      const char *dot = ".";
      const char *tagid = NULL;
      int skip_p = 0;
      int default_p = 0;
      int use_param_p = 0;
      char *newval;

      d->reorder_fn = NULL;
      for (oo = f->opt; oo; oo = oo->next)
        if (strcmp (oo->name, "dot") == 0)
    dot = oo->info;
        else if (strcmp (oo->name, "tag") == 0)
    tagid = oo->info;
        else if (strcmp (oo->name, "skip") == 0)
    skip_p = 1;
        else if (strcmp (oo->name, "default") == 0)
    default_p = 1;
        else if (strcmp (oo->name, "reorder") == 0)
    d->reorder_fn = oo->info;
        else if (strncmp (oo->name, "use_param", 9) == 0
           && (oo->name[9] == '\0' || ISDIGIT (oo->name[9])))
    use_param_p = 1;

      if (skip_p)
        continue;

      if (union_p && tagid)
        {
    oprintf (d->of, "%*scase %s:\n", d->indent, "", tagid);
    d->indent += 2;
        }
      else if (union_p && default_p)
        {
    oprintf (d->of, "%*sdefault:\n", d->indent, "");
    d->indent += 2;
    seen_default_p = 1;
        }
      else if (! union_p && (default_p || tagid))
        error_at_line (d->line,
           "can't use `%s' outside a union on field `%s'",
           default_p ? "default" : "tag", f->name);
      else if (union_p && ! (default_p || tagid)
         && f->type->kind == TYPE_SCALAR)
        {
    fprintf (stderr,
  "%s:%d: warning: field `%s' is missing `tag' or `default' option\n",
       d->line->file, d->line->line, f->name);
    continue;
        }
      else if (union_p && ! (default_p || tagid))
        error_at_line (d->line,
           "field `%s' is missing `tag' or `default' option",
           f->name);

      d->line = &f->line;
      d->val = newval = xasprintf ("%s%s%s", oldval, dot, f->name);
      d->opt = f->opt;
      d->used_length = false;

      if (union_p && use_param_p && d->param == NULL)
        oprintf (d->of, "%*sgcc_unreachable ();\n", d->indent, "");
      else
        walk_type (f->type, d);

      free (newval);

      if (union_p)
        {
    oprintf (d->of, "%*sbreak;\n", d->indent, "");
    d->indent -= 2;
        }
    }
  d->reorder_fn = NULL;

  d->val = oldval;
  d->prev_val[1] = oldprevval1;
  d->prev_val[2] = oldprevval2;

  if (union_p && ! seen_default_p)
    {
      oprintf (d->of, "%*sdefault:\n", d->indent, "");
      oprintf (d->of, "%*s  break;\n", d->indent, "");
    }
  if (union_p)
    {
      oprintf (d->of, "%*s}\n", d->indent, "");
      d->indent -= 2;
    }
      }
      break;

    case TYPE_LANG_STRUCT:
      {
  type_p nt;
  for (nt = t->u.s.lang_struct; nt; nt = nt->next)
    if ((d->bitmap & nt->u.s.bitmap) == d->bitmap)
      break;
  if (nt == NULL)
    error_at_line (d->line, "structure `%s' differs between languages",
       t->u.s.tag);
  else
    walk_type (nt, d);
      }
      break;

    case TYPE_PARAM_STRUCT:
      {
  type_p *oldparam = d->param;

  d->param = t->u.param_struct.param;
  walk_type (t->u.param_struct.stru, d);
  d->param = oldparam;
      }
      break;

    default:
      gcc_unreachable ();
    }
}

/* process_field routine for marking routines.  */

static void
write_types_process_field (type_p f, const struct walk_type_data *d)
{
  const struct write_types_data *wtd;
  const char *cast = d->needs_cast_p ? "(void *)" : "";
  wtd = (const struct write_types_data *) d->cookie;

  switch (f->kind)
    {
    case TYPE_POINTER:
      oprintf (d->of, "%*s%s (%s%s", d->indent, "",
         wtd->subfield_marker_routine, cast, d->val);
      if (wtd->param_prefix)
  {
    oprintf (d->of, ", %s", d->prev_val[3]);
    if (d->orig_s)
      {
        oprintf (d->of, ", gt_%s_", wtd->param_prefix);
        output_mangled_typename (d->of, d->orig_s);
      }
    else
      oprintf (d->of, ", gt_%sa_%s", wtd->param_prefix, d->prev_val[0]);
  }
      oprintf (d->of, ");\n");
      if (d->reorder_fn && wtd->reorder_note_routine)
  oprintf (d->of, "%*s%s (%s%s, %s, %s);\n", d->indent, "",
     wtd->reorder_note_routine, cast, d->val,
     d->prev_val[3], d->reorder_fn);
      break;

    case TYPE_STRING:
      if (wtd->param_prefix == NULL)
  break;

    case TYPE_STRUCT:
    case TYPE_UNION:
    case TYPE_LANG_STRUCT:
    case TYPE_PARAM_STRUCT:
      oprintf (d->of, "%*sgt_%s_", d->indent, "", wtd->prefix);
      output_mangled_typename (d->of, f);
      oprintf (d->of, " (%s%s);\n", cast, d->val);
      if (d->reorder_fn && wtd->reorder_note_routine)
  oprintf (d->of, "%*s%s (%s%s, %s%s, %s);\n", d->indent, "",
     wtd->reorder_note_routine, cast, d->val, cast, d->val,
     d->reorder_fn);
      break;

    case TYPE_SCALAR:
      break;

    default:
      gcc_unreachable ();
    }
}

/* For S, a structure that's part of ORIG_S, and using parameters
   PARAM, write out a routine that:
   - Takes a parameter, a void * but actually of type *S
   - If SEEN_ROUTINE returns nonzero, calls write_types_process_field on each
     field of S or its substructures and (in some cases) things
     that are pointed to by S.
*/

static void
write_func_for_structure (type_p orig_s, type_p s, type_p *param,
        const struct write_types_data *wtd)
{
  const char *fn = s->u.s.line.file;
  int i;
  const char *chain_next = NULL;
  const char *chain_prev = NULL;
  options_p opt;
  struct walk_type_data d;

  /* This is a hack, and not the good kind either.  */
  for (i = NUM_PARAM - 1; i >= 0; i--)
    if (param && param[i] && param[i]->kind == TYPE_POINTER
  && UNION_OR_STRUCT_P (param[i]->u.p))
      fn = param[i]->u.p->u.s.line.file;

  memset (&d, 0, sizeof (d));
  d.of = get_output_file_with_visibility (fn);

  for (opt = s->u.s.opt; opt; opt = opt->next)
    if (strcmp (opt->name, "chain_next") == 0)
      chain_next = opt->info;
    else if (strcmp (opt->name, "chain_prev") == 0)
      chain_prev = opt->info;

  if (chain_prev != NULL && chain_next == NULL)
    error_at_line (&s->u.s.line, "chain_prev without chain_next");

  d.process_field = write_types_process_field;
  d.cookie = wtd;
  d.orig_s = orig_s;
  d.opt = s->u.s.opt;
  d.line = &s->u.s.line;
  d.bitmap = s->u.s.bitmap;
  d.param = param;
  d.prev_val[0] = "*x";
  d.prev_val[1] = "not valid postage";  /* Guarantee an error.  */
  d.prev_val[3] = "x";
  d.val = "(*x)";

  oprintf (d.of, "\n");
  oprintf (d.of, "void\n");
  if (param == NULL)
    oprintf (d.of, "gt_%sx_%s", wtd->prefix, orig_s->u.s.tag);
  else
    {
      oprintf (d.of, "gt_%s_", wtd->prefix);
      output_mangled_typename (d.of, orig_s);
    }
  oprintf (d.of, " (void *x_p)\n");
  oprintf (d.of, "{\n");
  oprintf (d.of, "  %s %s * %sx = (%s %s *)x_p;\n",
     s->kind == TYPE_UNION ? "union" : "struct", s->u.s.tag,
     chain_next == NULL ? "const " : "",
     s->kind == TYPE_UNION ? "union" : "struct", s->u.s.tag);
  if (chain_next != NULL)
    oprintf (d.of, "  %s %s * xlimit = x;\n",
       s->kind == TYPE_UNION ? "union" : "struct", s->u.s.tag);
  if (chain_next == NULL)
    {
      oprintf (d.of, "  if (%s (x", wtd->marker_routine);
      if (wtd->param_prefix)
  {
    oprintf (d.of, ", x, gt_%s_", wtd->param_prefix);
    output_mangled_typename (d.of, orig_s);
  }
      oprintf (d.of, "))\n");
    }
  else
    {
      oprintf (d.of, "  while (%s (xlimit", wtd->marker_routine);
      if (wtd->param_prefix)
  {
    oprintf (d.of, ", xlimit, gt_%s_", wtd->param_prefix);
    output_mangled_typename (d.of, orig_s);
  }
      oprintf (d.of, "))\n");
      oprintf (d.of, "   xlimit = (");
      d.prev_val[2] = "*xlimit";
      output_escaped_param (&d, chain_next, "chain_next");
      oprintf (d.of, ");\n");
      if (chain_prev != NULL)
  {
    oprintf (d.of, "  if (x != xlimit)\n");
    oprintf (d.of, "    for (;;)\n");
    oprintf (d.of, "      {\n");
    oprintf (d.of, "        %s %s * const xprev = (",
       s->kind == TYPE_UNION ? "union" : "struct", s->u.s.tag);

    d.prev_val[2] = "*x";
    output_escaped_param (&d, chain_prev, "chain_prev");
    oprintf (d.of, ");\n");
    oprintf (d.of, "        if (xprev == NULL) break;\n");
    oprintf (d.of, "        x = xprev;\n");
    oprintf (d.of, "        (void) %s (xprev",
       wtd->marker_routine);
    if (wtd->param_prefix)
      {
        oprintf (d.of, ", xprev, gt_%s_", wtd->param_prefix);
        output_mangled_typename (d.of, orig_s);
      }
    oprintf (d.of, ");\n");
    oprintf (d.of, "      }\n");
  }
      oprintf (d.of, "  while (x != xlimit)\n");
    }
  oprintf (d.of, "    {\n");

  d.prev_val[2] = "*x";
  d.indent = 6;
  walk_type (s, &d);

  if (chain_next != NULL)
    {
      oprintf (d.of, "      x = (");
      output_escaped_param (&d, chain_next, "chain_next");
      oprintf (d.of, ");\n");
    }

  oprintf (d.of, "    }\n");
  oprintf (d.of, "}\n");
}

/* Write out marker routines for STRUCTURES and PARAM_STRUCTS.  */

static void
write_types (type_p structures, type_p param_structs,
       const struct write_types_data *wtd)
{
  type_p s;

  oprintf (header_file, "\n/* %s*/\n", wtd->comment);
  for (s = structures; s; s = s->next)
    if (s->gc_used == GC_POINTED_TO
  || s->gc_used == GC_MAYBE_POINTED_TO)
      {
  options_p opt;

  if (s->gc_used == GC_MAYBE_POINTED_TO
      && s->u.s.line.file == NULL)
    continue;

  oprintf (header_file, "#define gt_%s_", wtd->prefix);
  output_mangled_typename (header_file, s);
  oprintf (header_file, "(X) do { \\\n");
  oprintf (header_file,
     "  if (X != NULL) gt_%sx_%s (X);\\\n", wtd->prefix,
     s->u.s.tag);
  oprintf (header_file,
     "  } while (0)\n");

  for (opt = s->u.s.opt; opt; opt = opt->next)
    if (strcmp (opt->name, "ptr_alias") == 0)
      {
        type_p t = (type_p) opt->info;
        if (t->kind == TYPE_STRUCT
      || t->kind == TYPE_UNION
      || t->kind == TYPE_LANG_STRUCT)
    oprintf (header_file,
       "#define gt_%sx_%s gt_%sx_%s\n",
       wtd->prefix, s->u.s.tag, wtd->prefix, t->u.s.tag);
        else
    error_at_line (&s->u.s.line,
             "structure alias is not a structure");
        break;
      }
  if (opt)
    continue;

  /* Declare the marker procedure only once.  */
  oprintf (header_file,
     "extern void gt_%sx_%s (void *);\n",
     wtd->prefix, s->u.s.tag);

  if (s->u.s.line.file == NULL)
    {
      fprintf (stderr, "warning: structure `%s' used but not defined\n",
         s->u.s.tag);
      continue;
    }

  if (s->kind == TYPE_LANG_STRUCT)
    {
      type_p ss;
      for (ss = s->u.s.lang_struct; ss; ss = ss->next)
        write_func_for_structure (s, ss, NULL, wtd);
    }
  else
    write_func_for_structure (s, s, NULL, wtd);
      }

  for (s = param_structs; s; s = s->next)
    if (s->gc_used == GC_POINTED_TO)
      {
  type_p * param = s->u.param_struct.param;
  type_p stru = s->u.param_struct.stru;

  /* Declare the marker procedure.  */
  oprintf (header_file, "extern void gt_%s_", wtd->prefix);
  output_mangled_typename (header_file, s);
  oprintf (header_file, " (void *);\n");

  if (stru->u.s.line.file == NULL)
    {
      fprintf (stderr, "warning: structure `%s' used but not defined\n",
         s->u.s.tag);
      continue;
    }

  if (stru->kind == TYPE_LANG_STRUCT)
    {
      type_p ss;
      for (ss = stru->u.s.lang_struct; ss; ss = ss->next)
        write_func_for_structure (s, ss, param, wtd);
    }
  else
    write_func_for_structure (s, stru, param, wtd);
      }
}

static const struct write_types_data ggc_wtd =
{
  "ggc_m", NULL, "ggc_mark", "ggc_test_and_set_mark", NULL,
  "GC marker procedures.  "
};

static const struct write_types_data pch_wtd =
{
  "pch_n", "pch_p", "gt_pch_note_object", "gt_pch_note_object",
  "gt_pch_note_reorder",
  "PCH type-walking procedures.  "
};

/* Write out the local pointer-walking routines.  */

/* process_field routine for local pointer-walking.  */

static void
write_types_local_process_field (type_p f, const struct walk_type_data *d)
{
  switch (f->kind)
    {
    case TYPE_POINTER:
    case TYPE_STRUCT:
    case TYPE_UNION:
    case TYPE_LANG_STRUCT:
    case TYPE_PARAM_STRUCT:
    case TYPE_STRING:
      oprintf (d->of, "%*sif ((void *)(%s) == this_obj)\n", d->indent, "",
         d->prev_val[3]);
      oprintf (d->of, "%*s  op (&(%s), cookie);\n", d->indent, "", d->val);
      break;

    case TYPE_SCALAR:
      break;

    default:
      gcc_unreachable ();
    }
}

/* For S, a structure that's part of ORIG_S, and using parameters
   PARAM, write out a routine that:
   - Is of type gt_note_pointers
   - Calls PROCESS_FIELD on each field of S or its substructures.
*/

static void
write_local_func_for_structure (type_p orig_s, type_p s, type_p *param)
{
  const char *fn = s->u.s.line.file;
  int i;
  struct walk_type_data d;

  /* This is a hack, and not the good kind either.  */
  for (i = NUM_PARAM - 1; i >= 0; i--)
    if (param && param[i] && param[i]->kind == TYPE_POINTER
  && UNION_OR_STRUCT_P (param[i]->u.p))
      fn = param[i]->u.p->u.s.line.file;

  memset (&d, 0, sizeof (d));
  d.of = get_output_file_with_visibility (fn);

  d.process_field = write_types_local_process_field;
  d.opt = s->u.s.opt;
  d.line = &s->u.s.line;
  d.bitmap = s->u.s.bitmap;
  d.param = param;
  d.prev_val[0] = d.prev_val[2] = "*x";
  d.prev_val[1] = "not valid postage";  /* Guarantee an error.  */
  d.prev_val[3] = "x";
  d.val = "(*x)";
  d.fn_wants_lvalue = true;

  oprintf (d.of, "\n");
  oprintf (d.of, "void\n");
  oprintf (d.of, "gt_pch_p_");
  output_mangled_typename (d.of, orig_s);
  oprintf (d.of, " (ATTRIBUTE_UNUSED void *this_obj,\n"
     "\tvoid *x_p,\n"
     "\tATTRIBUTE_UNUSED gt_pointer_operator op,\n"
     "\tATTRIBUTE_UNUSED void *cookie)\n");
  oprintf (d.of, "{\n");
  oprintf (d.of, "  %s %s * const x ATTRIBUTE_UNUSED = (%s %s *)x_p;\n",
     s->kind == TYPE_UNION ? "union" : "struct", s->u.s.tag,
     s->kind == TYPE_UNION ? "union" : "struct", s->u.s.tag);
  d.indent = 2;
  walk_type (s, &d);
  oprintf (d.of, "}\n");
}

/* Write out local marker routines for STRUCTURES and PARAM_STRUCTS.  */

static void
write_local (type_p structures, type_p param_structs)
{
  type_p s;

  oprintf (header_file, "\n/* Local pointer-walking routines.  */\n");
  for (s = structures; s; s = s->next)
    if (s->gc_used == GC_POINTED_TO
  || s->gc_used == GC_MAYBE_POINTED_TO)
      {
  options_p opt;

  if (s->u.s.line.file == NULL)
    continue;

  for (opt = s->u.s.opt; opt; opt = opt->next)
    if (strcmp (opt->name, "ptr_alias") == 0)
      {
        type_p t = (type_p) opt->info;
        if (t->kind == TYPE_STRUCT
      || t->kind == TYPE_UNION
      || t->kind == TYPE_LANG_STRUCT)
    {
      oprintf (header_file, "#define gt_pch_p_");
      output_mangled_typename (header_file, s);
      oprintf (header_file, " gt_pch_p_");
      output_mangled_typename (header_file, t);
      oprintf (header_file, "\n");
    }
        else
    error_at_line (&s->u.s.line,
             "structure alias is not a structure");
        break;
      }
  if (opt)
    continue;

  /* Declare the marker procedure only once.  */
  oprintf (header_file, "extern void gt_pch_p_");
  output_mangled_typename (header_file, s);
  oprintf (header_file,
   "\n    (void *, void *, gt_pointer_operator, void *);\n");

  if (s->kind == TYPE_LANG_STRUCT)
    {
      type_p ss;
      for (ss = s->u.s.lang_struct; ss; ss = ss->next)
        write_local_func_for_structure (s, ss, NULL);
    }
  else
    write_local_func_for_structure (s, s, NULL);
      }

  for (s = param_structs; s; s = s->next)
    if (s->gc_used == GC_POINTED_TO)
      {
  type_p * param = s->u.param_struct.param;
  type_p stru = s->u.param_struct.stru;

  /* Declare the marker procedure.  */
  oprintf (header_file, "extern void gt_pch_p_");
  output_mangled_typename (header_file, s);
  oprintf (header_file,
   "\n    (void *, void *, gt_pointer_operator, void *);\n");

  if (stru->u.s.line.file == NULL)
    {
      fprintf (stderr, "warning: structure `%s' used but not defined\n",
         s->u.s.tag);
      continue;
    }

  if (stru->kind == TYPE_LANG_STRUCT)
    {
      type_p ss;
      for (ss = stru->u.s.lang_struct; ss; ss = ss->next)
        write_local_func_for_structure (s, ss, param);
    }
  else
    write_local_func_for_structure (s, stru, param);
      }
}

/* Write out the 'enum' definition for gt_types_enum.  */

static void
write_enum_defn (type_p structures, type_p param_structs)
{
  type_p s;

  oprintf (header_file, "\n/* Enumeration of types known.  */\n");
  oprintf (header_file, "enum gt_types_enum {\n");
  for (s = structures; s; s = s->next)
    if (s->gc_used == GC_POINTED_TO
  || s->gc_used == GC_MAYBE_POINTED_TO)
      {
  if (s->gc_used == GC_MAYBE_POINTED_TO
      && s->u.s.line.file == NULL)
    continue;

  oprintf (header_file, " gt_ggc_e_");
  output_mangled_typename (header_file, s);
  oprintf (header_file, ", \n");
      }
  for (s = param_structs; s; s = s->next)
    if (s->gc_used == GC_POINTED_TO)
      {
  oprintf (header_file, " gt_e_");
  output_mangled_typename (header_file, s);
  oprintf (header_file, ", \n");
      }
  oprintf (header_file, " gt_types_enum_last\n");
  oprintf (header_file, "};\n");
}

/* Might T contain any non-pointer elements?  */

static int
contains_scalar_p (type_p t)
{
  switch (t->kind)
    {
    case TYPE_STRING:
    case TYPE_POINTER:
      return 0;
    case TYPE_ARRAY:
      return contains_scalar_p (t->u.a.p);
    default:
      /* Could also check for structures that have no non-pointer
   fields, but there aren't enough of those to worry about.  */
      return 1;
    }
}

/* Mangle FN and print it to F.  */

static void
put_mangled_filename (outf_p f, const char *fn)
{
  const char *name = get_output_file_name (fn);
  for (; *name != 0; name++)
    if (ISALNUM (*name))
      oprintf (f, "%c", *name);
    else
      oprintf (f, "%c", '_');
}

/* Finish off the currently-created root tables in FLP.  PFX, TNAME,
   LASTNAME, and NAME are all strings to insert in various places in
   the resulting code.  */

static void
finish_root_table (struct flist *flp, const char *pfx, const char *lastname,
       const char *tname, const char *name)
{
  struct flist *fli2;

  for (fli2 = flp; fli2; fli2 = fli2->next)
    if (fli2->started_p)
      {
  oprintf (fli2->f, "  %s\n", lastname);
  oprintf (fli2->f, "};\n\n");
      }

  for (fli2 = flp; fli2; fli2 = fli2->next)
    if (fli2->started_p)
      {
  lang_bitmap bitmap = get_base_file_bitmap (fli2->name);
  int fnum;

  for (fnum = 0; bitmap != 0; fnum++, bitmap >>= 1)
    if (bitmap & 1)
      {
        oprintf (base_files[fnum],
           "extern const struct %s gt_%s_",
           tname, pfx);
        put_mangled_filename (base_files[fnum], fli2->name);
        oprintf (base_files[fnum], "[];\n");
      }
      }

  {
    size_t fnum;
    for (fnum = 0; fnum < NUM_BASE_FILES; fnum++)
      oprintf (base_files [fnum],
         "const struct %s * const %s[] = {\n",
         tname, name);
  }


  for (fli2 = flp; fli2; fli2 = fli2->next)
    if (fli2->started_p)
      {
  lang_bitmap bitmap = get_base_file_bitmap (fli2->name);
  int fnum;

  fli2->started_p = 0;

  for (fnum = 0; bitmap != 0; fnum++, bitmap >>= 1)
    if (bitmap & 1)
      {
        oprintf (base_files[fnum], "  gt_%s_", pfx);
        put_mangled_filename (base_files[fnum], fli2->name);
        oprintf (base_files[fnum], ",\n");
      }
      }

  {
    size_t fnum;
    for (fnum = 0; fnum < NUM_BASE_FILES; fnum++)
      {
  oprintf (base_files[fnum], "  NULL\n");
  oprintf (base_files[fnum], "};\n");
      }
  }
}

/* Write out to F the table entry and any marker routines needed to
   mark NAME as TYPE.  The original variable is V, at LINE.
   HAS_LENGTH is nonzero iff V was a variable-length array.  IF_MARKED
   is nonzero iff we are building the root table for hash table caches.  */

static void
write_root (outf_p f, pair_p v, type_p type, const char *name, int has_length,
      struct fileloc *line, const char *if_marked)
{
  switch (type->kind)
    {
    case TYPE_STRUCT:
      {
  pair_p fld;
  for (fld = type->u.s.fields; fld; fld = fld->next)
    {
      int skip_p = 0;
      const char *desc = NULL;
      options_p o;

      for (o = fld->opt; o; o = o->next)
        if (strcmp (o->name, "skip") == 0)
    skip_p = 1;
        else if (strcmp (o->name, "desc") == 0)
    desc = o->info;
        else
    error_at_line (line,
           "field `%s' of global `%s' has unknown option `%s'",
             fld->name, name, o->name);

      if (skip_p)
        continue;
      else if (desc && fld->type->kind == TYPE_UNION)
        {
    pair_p validf = NULL;
    pair_p ufld;

    for (ufld = fld->type->u.s.fields; ufld; ufld = ufld->next)
      {
        const char *tag = NULL;
        options_p oo;

        for (oo = ufld->opt; oo; oo = oo->next)
          if (strcmp (oo->name, "tag") == 0)
      tag = oo->info;
        if (tag == NULL || strcmp (tag, desc) != 0)
          continue;
        if (validf != NULL)
          error_at_line (line,
         "both `%s.%s.%s' and `%s.%s.%s' have tag `%s'",
             name, fld->name, validf->name,
             name, fld->name, ufld->name,
             tag);
        validf = ufld;
      }
    if (validf != NULL)
      {
        char *newname;
        newname = xasprintf ("%s.%s.%s",
           name, fld->name, validf->name);
        write_root (f, v, validf->type, newname, 0, line,
        if_marked);
        free (newname);
      }
        }
      else if (desc)
        error_at_line (line,
         "global `%s.%s' has `desc' option but is not union",
           name, fld->name);
      else
        {
    char *newname;
    newname = xasprintf ("%s.%s", name, fld->name);
    write_root (f, v, fld->type, newname, 0, line, if_marked);
    free (newname);
        }
    }
      }
      break;

    case TYPE_ARRAY:
      {
  char *newname;
  newname = xasprintf ("%s[0]", name);
  write_root (f, v, type->u.a.p, newname, has_length, line, if_marked);
  free (newname);
      }
      break;

    case TYPE_POINTER:
      {
  type_p ap, tp;

  oprintf (f, "  {\n");
  oprintf (f, "    &%s,\n", name);
  oprintf (f, "    1");

  for (ap = v->type; ap->kind == TYPE_ARRAY; ap = ap->u.a.p)
    if (ap->u.a.len[0])
      oprintf (f, " * (%s)", ap->u.a.len);
    else if (ap == v->type)
      oprintf (f, " * ARRAY_SIZE (%s)", v->name);
  oprintf (f, ",\n");
  oprintf (f, "    sizeof (%s", v->name);
  for (ap = v->type; ap->kind == TYPE_ARRAY; ap = ap->u.a.p)
    oprintf (f, "[0]");
  oprintf (f, "),\n");

  tp = type->u.p;

  if (! has_length && UNION_OR_STRUCT_P (tp))
    {
      oprintf (f, "    &gt_ggc_mx_%s,\n", tp->u.s.tag);
      oprintf (f, "    &gt_pch_nx_%s", tp->u.s.tag);
    }
  else if (! has_length && tp->kind == TYPE_PARAM_STRUCT)
    {
      oprintf (f, "    &gt_ggc_m_");
      output_mangled_typename (f, tp);
      oprintf (f, ",\n    &gt_pch_n_");
      output_mangled_typename (f, tp);
    }
  else if (has_length
     && (tp->kind == TYPE_POINTER || UNION_OR_STRUCT_P (tp)))
    {
      oprintf (f, "    &gt_ggc_ma_%s,\n", name);
      oprintf (f, "    &gt_pch_na_%s", name);
    }
  else
    {
      error_at_line (line,
         "global `%s' is pointer to unimplemented type",
         name);
    }
  if (if_marked)
    oprintf (f, ",\n    &%s", if_marked);
  oprintf (f, "\n  },\n");
      }
      break;

    case TYPE_STRING:
      {
  oprintf (f, "  {\n");
  oprintf (f, "    &%s,\n", name);
  oprintf (f, "    1, \n");
  oprintf (f, "    sizeof (%s),\n", v->name);
  oprintf (f, "    &gt_ggc_m_S,\n");
  oprintf (f, "    (gt_pointer_walker) &gt_pch_n_S\n");
  oprintf (f, "  },\n");
      }
      break;

    case TYPE_SCALAR:
      break;

    default:
      error_at_line (line,
         "global `%s' is unimplemented type",
         name);
    }
}

/* This generates a routine to walk an array.  */

static void
write_array (outf_p f, pair_p v, const struct write_types_data *wtd)
{
  struct walk_type_data d;
  char *prevval3;

  memset (&d, 0, sizeof (d));
  d.of = f;
  d.cookie = wtd;
  d.indent = 2;
  d.line = &v->line;
  d.opt = v->opt;
  d.bitmap = get_base_file_bitmap (v->line.file);
  d.param = NULL;

  d.prev_val[3] = prevval3 = xasprintf ("&%s", v->name);

  if (wtd->param_prefix)
    {
      oprintf (f, "static void gt_%sa_%s\n", wtd->param_prefix, v->name);
      oprintf (f,
       "    (void *, void *, gt_pointer_operator, void *);\n");
      oprintf (f, "static void gt_%sa_%s (ATTRIBUTE_UNUSED void *this_obj,\n",
         wtd->param_prefix, v->name);
      oprintf (d.of,
         "      ATTRIBUTE_UNUSED void *x_p,\n"
         "      ATTRIBUTE_UNUSED gt_pointer_operator op,\n"
         "      ATTRIBUTE_UNUSED void * cookie)\n");
      oprintf (d.of, "{\n");
      d.prev_val[0] = d.prev_val[1] = d.prev_val[2] = d.val = v->name;
      d.process_field = write_types_local_process_field;
      walk_type (v->type, &d);
      oprintf (f, "}\n\n");
    }

  d.opt = v->opt;
  oprintf (f, "static void gt_%sa_%s (void *);\n",
     wtd->prefix, v->name);
  oprintf (f, "static void\ngt_%sa_%s (ATTRIBUTE_UNUSED void *x_p)\n",
     wtd->prefix, v->name);
  oprintf (f, "{\n");
  d.prev_val[0] = d.prev_val[1] = d.prev_val[2] = d.val = v->name;
  d.process_field = write_types_process_field;
  walk_type (v->type, &d);
  free (prevval3);
  oprintf (f, "}\n\n");
}

/* Output a table describing the locations and types of VARIABLES.  */

static void
write_roots (pair_p variables)
{
  pair_p v;
  struct flist *flp = NULL;

  for (v = variables; v; v = v->next)
    {
      outf_p f = get_output_file_with_visibility (v->line.file);
      struct flist *fli;
      const char *length = NULL;
      int deletable_p = 0;
      options_p o;

      for (o = v->opt; o; o = o->next)
  if (strcmp (o->name, "length") == 0)
    length = o->info;
  else if (strcmp (o->name, "deletable") == 0)
    deletable_p = 1;
  else if (strcmp (o->name, "param_is") == 0)
    ;
  else if (strncmp (o->name, "param", 5) == 0
     && ISDIGIT (o->name[5])
     && strcmp (o->name + 6, "_is") == 0)
    ;
  else if (strcmp (o->name, "if_marked") == 0)
    ;
  else
    error_at_line (&v->line,
       "global `%s' has unknown option `%s'",
       v->name, o->name);

      for (fli = flp; fli; fli = fli->next)
  if (fli->f == f)
    break;
      if (fli == NULL)
  {
    fli = XNEW (struct flist);
    fli->f = f;
    fli->next = flp;
    fli->started_p = 0;
    fli->name = v->line.file;
    flp = fli;

    oprintf (f, "\n/* GC roots.  */\n\n");
  }

      if (! deletable_p
    && length
    && v->type->kind == TYPE_POINTER
    && (v->type->u.p->kind == TYPE_POINTER
        || v->type->u.p->kind == TYPE_STRUCT))
  {
    write_array (f, v, &ggc_wtd);
    write_array (f, v, &pch_wtd);
  }
    }

  for (v = variables; v; v = v->next)
    {
      outf_p f = get_output_file_with_visibility (v->line.file);
      struct flist *fli;
      int skip_p = 0;
      int length_p = 0;
      options_p o;

      for (o = v->opt; o; o = o->next)
  if (strcmp (o->name, "length") == 0)
    length_p = 1;
  else if (strcmp (o->name, "deletable") == 0
     || strcmp (o->name, "if_marked") == 0)
    skip_p = 1;

      if (skip_p)
  continue;

      for (fli = flp; fli; fli = fli->next)
  if (fli->f == f)
    break;
      if (! fli->started_p)
  {
    fli->started_p = 1;

    oprintf (f, "const struct ggc_root_tab gt_ggc_r_");
    put_mangled_filename (f, v->line.file);
    oprintf (f, "[] = {\n");
  }

      write_root (f, v, v->type, v->name, length_p, &v->line, NULL);
    }

  finish_root_table (flp, "ggc_r", "LAST_GGC_ROOT_TAB", "ggc_root_tab",
         "gt_ggc_rtab");

  for (v = variables; v; v = v->next)
    {
      outf_p f = get_output_file_with_visibility (v->line.file);
      struct flist *fli;
      int skip_p = 1;
      options_p o;

      for (o = v->opt; o; o = o->next)
  if (strcmp (o->name, "deletable") == 0)
    skip_p = 0;
  else if (strcmp (o->name, "if_marked") == 0)
    skip_p = 1;

      if (skip_p)
  continue;

      for (fli = flp; fli; fli = fli->next)
  if (fli->f == f)
    break;
      if (! fli->started_p)
  {
    fli->started_p = 1;

    oprintf (f, "const struct ggc_root_tab gt_ggc_rd_");
    put_mangled_filename (f, v->line.file);
    oprintf (f, "[] = {\n");
  }

      oprintf (f, "  { &%s, 1, sizeof (%s), NULL, NULL },\n",
         v->name, v->name);
    }

  finish_root_table (flp, "ggc_rd", "LAST_GGC_ROOT_TAB", "ggc_root_tab",
         "gt_ggc_deletable_rtab");

  for (v = variables; v; v = v->next)
    {
      outf_p f = get_output_file_with_visibility (v->line.file);
      struct flist *fli;
      const char *if_marked = NULL;
      int length_p = 0;
      options_p o;

      for (o = v->opt; o; o = o->next)
  if (strcmp (o->name, "length") == 0)
    length_p = 1;
  else if (strcmp (o->name, "if_marked") == 0)
    if_marked = o->info;

      if (if_marked == NULL)
  continue;

      if (v->type->kind != TYPE_POINTER
    || v->type->u.p->kind != TYPE_PARAM_STRUCT
    || v->type->u.p->u.param_struct.stru != find_structure ("htab", 0))
  {
    error_at_line (&v->line, "if_marked option used but not hash table");
    continue;
  }

      for (fli = flp; fli; fli = fli->next)
  if (fli->f == f)
    break;
      if (! fli->started_p)
  {
    fli->started_p = 1;

    oprintf (f, "const struct ggc_cache_tab gt_ggc_rc_");
    put_mangled_filename (f, v->line.file);
    oprintf (f, "[] = {\n");
  }

      write_root (f, v, v->type->u.p->u.param_struct.param[0],
         v->name, length_p, &v->line, if_marked);
    }

  finish_root_table (flp, "ggc_rc", "LAST_GGC_CACHE_TAB", "ggc_cache_tab",
         "gt_ggc_cache_rtab");

  for (v = variables; v; v = v->next)
    {
      outf_p f = get_output_file_with_visibility (v->line.file);
      struct flist *fli;
      int length_p = 0;
      int if_marked_p = 0;
      options_p o;

      for (o = v->opt; o; o = o->next)
  if (strcmp (o->name, "length") == 0)
    length_p = 1;
  else if (strcmp (o->name, "if_marked") == 0)
    if_marked_p = 1;

      if (! if_marked_p)
  continue;

      for (fli = flp; fli; fli = fli->next)
  if (fli->f == f)
    break;
      if (! fli->started_p)
  {
    fli->started_p = 1;

    oprintf (f, "const struct ggc_root_tab gt_pch_rc_");
    put_mangled_filename (f, v->line.file);
    oprintf (f, "[] = {\n");
  }

      write_root (f, v, v->type, v->name, length_p, &v->line, NULL);
    }

  finish_root_table (flp, "pch_rc", "LAST_GGC_ROOT_TAB", "ggc_root_tab",
         "gt_pch_cache_rtab");

  for (v = variables; v; v = v->next)
    {
      outf_p f = get_output_file_with_visibility (v->line.file);
      struct flist *fli;
      int skip_p = 0;
      options_p o;

      for (o = v->opt; o; o = o->next)
  if (strcmp (o->name, "deletable") == 0
      || strcmp (o->name, "if_marked") == 0)
    skip_p = 1;

      if (skip_p)
  continue;

      if (! contains_scalar_p (v->type))
  continue;

      for (fli = flp; fli; fli = fli->next)
  if (fli->f == f)
    break;
      if (! fli->started_p)
  {
    fli->started_p = 1;

    oprintf (f, "const struct ggc_root_tab gt_pch_rs_");
    put_mangled_filename (f, v->line.file);
    oprintf (f, "[] = {\n");
  }

      oprintf (f, "  { &%s, 1, sizeof (%s), NULL, NULL },\n",
         v->name, v->name);
    }

  finish_root_table (flp, "pch_rs", "LAST_GGC_ROOT_TAB", "ggc_root_tab",
         "gt_pch_scalar_rtab");
}


extern int main (int argc, char **argv);
int
main(int ARG_UNUSED (argc), char ** ARG_UNUSED (argv))
{
  unsigned i;
  static struct fileloc pos = { __FILE__, __LINE__ };
  unsigned j;

  gen_rtx_next ();

  srcdir_len = strlen (srcdir);

  do_scalar_typedef ("CUMULATIVE_ARGS", &pos);
  do_scalar_typedef ("REAL_VALUE_TYPE", &pos);
  do_scalar_typedef ("uint8", &pos);
  do_scalar_typedef ("jword", &pos);
  do_scalar_typedef ("JCF_u2", &pos);
#ifdef USE_MAPPED_LOCATION
  do_scalar_typedef ("location_t", &pos);
  do_scalar_typedef ("source_locus", &pos);
#endif
  do_scalar_typedef ("void", &pos);

  do_typedef ("PTR", create_pointer (resolve_typedef ("void", &pos)), &pos);

  do_typedef ("HARD_REG_SET", create_array (
        create_scalar_type ("unsigned long", strlen ("unsigned long")),
        "2"), &pos);

  for (i = 0; i < NUM_GT_FILES; i++)
    {
      int dupflag = 0;
      /* Omit if already seen.  */
      for (j = 0; j < i; j++)
        {
          if (!strcmp (all_files[i], all_files[j]))
            {
              dupflag = 1;
              break;
            }
        }
      if (!dupflag)
        parse_file (all_files[i]);
#ifndef USE_MAPPED_LOCATION
      /* temporary kludge - gengtype doesn't handle conditionals.
   Manually add source_locus *after* we've processed input.h.  */
      if (i == 0)
  do_typedef ("source_locus", create_pointer (resolve_typedef ("location_t", &pos)), &pos);
#endif
    }

  if (hit_error != 0)
    exit (1);

  set_gc_used (variables);

  open_base_files ();
  write_enum_defn (structures, param_structs);
  write_types (structures, param_structs, &ggc_wtd);
  write_types (structures, param_structs, &pch_wtd);
  write_local (structures, param_structs);
  write_roots (variables);
  write_rtx_next ();
  close_output_files ();

  return (hit_error != 0);
}

---