/* Language-dependent node constructors for parse phase of GNU compiler.
   Copyright (C) 1992, 93, 1994  Free Software Foundation, Inc.

This file is part of GNU CC.

GNU CC 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.

GNU CC 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 GNU CC; see the file COPYING.  If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */

#include "config.h"
#include "obstack.h"
#include "tree.h"
#include "ch-tree.h"

/* Here is how primitive or already-canonicalized types' 
   hash codes are made.  */
#define TYPE_HASH(TYPE) ((HOST_WIDE_INT) (TYPE) & 0777777)

extern void error PROTO((char *, ...));
extern int  get_type_precision PROTO((tree, tree));

extern struct obstack permanent_obstack;
/* This is special sentinel used to communicate from build_string_type
   to layout_chill_range_type for the index range of a string. */
tree string_index_type_dummy;

/* Build a chill string type.
   For a character string, ELT_TYPE==char_type_node; 
   for a bit-string, ELT_TYPE==boolean_type_node. */

tree
build_string_type (elt_type, length)
     tree elt_type;
     tree length;
{
  register tree t;

  if (TREE_CODE (elt_type) == ERROR_MARK || TREE_CODE (length) == ERROR_MARK)
    return error_mark_node;

  /* Allocate the array after the pointer type,
     in case we free it in type_hash_canon.  */

  if (pass > 0 && TREE_CODE (length) == INTEGER_CST
      && ! tree_int_cst_equal (length, integer_zero_node)
      && compare_int_csts (LT_EXPR, TYPE_MAX_VALUE (chill_unsigned_type_node),
			   length))
    {
      error ("string length > UPPER (UINT)");
      length = integer_one_node;
    }

  /* Subtract 1 from length to get max index value.
     Note we cannot use size_binop for pass 1 expressions. */
  if (TREE_CODE (length) == INTEGER_CST || pass != 1)
    length = size_binop (MINUS_EXPR, length, integer_one_node);
  else
    length = build (MINUS_EXPR, sizetype, length, integer_one_node);

  t = make_node (elt_type == boolean_type_node ? SET_TYPE : ARRAY_TYPE);
  TREE_TYPE (t) = elt_type;

  MARK_AS_STRING_TYPE (t);

  TYPE_DOMAIN (t) = build_chill_range_type (string_index_type_dummy,
					    integer_zero_node, length);
  if (pass == 1 && TREE_CODE (length) == INTEGER_CST)
    TYPE_DOMAIN (t) = layout_chill_range_type (TYPE_DOMAIN (t), 0);

  if (pass != 1
      || (TREE_CODE (length) == INTEGER_CST && TYPE_SIZE (elt_type)))
    {
      if (TREE_CODE (t) == SET_TYPE)
	t = layout_powerset_type (t);
      else
	t = layout_chill_array_type (t);
    }
  return t;
}

tree
make_powerset_type (domain)
     tree domain;
{
  tree t = make_node (SET_TYPE);

  TREE_TYPE (t) = boolean_type_node;
  TYPE_DOMAIN (t) = domain;
  
  return t;
}

/* Used to layout both bitstring and powerset types. */

tree
layout_powerset_type (type)
     tree type;
{
  tree domain = TYPE_DOMAIN (type);

  if (! discrete_type_p (domain))
    {
      error ("Can only build a powerset from a discrete mode");
      return error_mark_node;
    }

  if (TREE_CODE (TYPE_MAX_VALUE (domain)) == ERROR_MARK ||
      TREE_CODE (TYPE_MIN_VALUE (domain)) == ERROR_MARK)
    return error_mark_node;

  if (TREE_CODE (TYPE_MAX_VALUE (domain)) != INTEGER_CST
      || TREE_CODE (TYPE_MIN_VALUE (domain)) != INTEGER_CST)
    {
      if (CH_BOOLS_TYPE_P (type))
	error ("non-constant bitstring size invalid");
      else
	error ("non-constant powerset size invalid");
      return error_mark_node;
    }

  if (TYPE_SIZE (type) == 0)
    layout_type (type);
  return type;
}

/* Build a SET_TYPE node whose elements are from the set of values
   in TYPE.  TYPE must be a discrete mode; we check for that here. */
tree
build_powerset_type (type)
     tree type;
{
  tree t = make_powerset_type (type);
  if (pass != 1)
    t = layout_powerset_type (t);
  return t;
}

tree
build_bitstring_type (size_in_bits)
     tree size_in_bits;
{
  return build_string_type (boolean_type_node, size_in_bits);
}

/* Return get_identifier (the concatenations of part1, part2, and part3). */

tree
get_identifier3 (part1, part2, part3)
     char *part1, *part2, *part3;
{
  char *buf = (char*)
    alloca (strlen(part1) + strlen(part2) + strlen(part3) + 1);
  sprintf (buf, "%s%s%s", part1, part2, part3);
  return get_identifier (buf);
}

/* Build an ALIAS_DECL for the prefix renamed clause:
   (OLD_PREFIX -> NEW_PREFIX) ! POSTFIX. */

tree
build_alias_decl (old_prefix, new_prefix, postfix)
     tree old_prefix, new_prefix, postfix;
{
  tree decl = make_node (ALIAS_DECL);

  char *postfix_pointer = IDENTIFIER_POINTER (postfix);
  int postfix_length = IDENTIFIER_LENGTH (postfix);
  int old_length = old_prefix ? IDENTIFIER_LENGTH(old_prefix) : 0;
  int new_length = new_prefix ? IDENTIFIER_LENGTH(new_prefix) : 0;

  char *buf = (char*) alloca (old_length + new_length + postfix_length + 3);

  /* Convert (OP->NP)!P!ALL to (OP!P->NP!P)!ALL */
  if (postfix_length > 1 && postfix_pointer[postfix_length-1] == '*')
    {
      int chopped_length = postfix_length - 2; /* Without final "!*" */
      if (old_prefix)
	sprintf (buf, "%s!%.*s", IDENTIFIER_POINTER (old_prefix),
		 chopped_length, postfix_pointer);
      else
	sprintf (buf, "%.*s", chopped_length, postfix_pointer);
      old_prefix = get_identifier (buf);
      if (new_prefix)
	sprintf (buf, "%s!%.*s", IDENTIFIER_POINTER (new_prefix),
		 chopped_length, postfix_pointer);
      else
	sprintf (buf, "%.*s", chopped_length, postfix_pointer);
      new_prefix = get_identifier (buf);
      postfix = ALL_POSTFIX;
    }

  DECL_OLD_PREFIX (decl) = old_prefix;
  DECL_NEW_PREFIX (decl) = new_prefix;
  DECL_POSTFIX (decl) = postfix;

  if (DECL_POSTFIX_ALL (decl))
    DECL_NAME (decl) = NULL_TREE;
  else if (new_prefix == NULL_TREE)
    DECL_NAME (decl) = postfix;
  else
    DECL_NAME (decl) = get_identifier3 (IDENTIFIER_POINTER (new_prefix),
					"!", IDENTIFIER_POINTER (postfix));

  return decl;
}

/* Return the "old name string" of an ALIAS_DECL. */

tree
decl_old_name (decl)
     tree decl;
{
  
  if (DECL_OLD_PREFIX (decl) == NULL_TREE)
    return DECL_POSTFIX (decl);
  return get_identifier3 (IDENTIFIER_POINTER (DECL_OLD_PREFIX (decl)),
			  "!", IDENTIFIER_POINTER (DECL_POSTFIX (decl)));
}

/* See if OLD_NAME (an identifier) matches the OLD_PREFIX!POSTFIX
   of ALIAS.  If so, return the corresponding NEW_NEW!POSTFIX. */

tree
decl_check_rename (alias, old_name)
     tree alias, old_name;
{
  char *old_pointer = IDENTIFIER_POINTER (old_name);
  int old_len = IDENTIFIER_LENGTH (old_name);
  if (DECL_OLD_PREFIX (alias))
    {
      int old_prefix_len = IDENTIFIER_LENGTH (DECL_OLD_PREFIX (alias));
      if (old_prefix_len >= old_len
	  || old_pointer[old_prefix_len] != '!'
	  || strncmp (old_pointer, IDENTIFIER_POINTER (DECL_OLD_PREFIX (alias)), old_prefix_len) != 0)
	return NULL_TREE;

      /* Skip the old prefix. */
      old_pointer += old_prefix_len + 1; /* Also skip the '!', */
    }
  if (DECL_POSTFIX_ALL (alias)
      || strcmp (IDENTIFIER_POINTER (DECL_POSTFIX (alias)), old_pointer) == 0)
    {
      if (DECL_NEW_PREFIX (alias))
	return get_identifier3 (IDENTIFIER_POINTER (DECL_NEW_PREFIX (alias)),
				"!", old_pointer);
      else if (old_pointer == IDENTIFIER_POINTER (old_name))
	return old_name;
      else
	return get_identifier (old_pointer);
    }
  else
    return NULL_TREE;
}

/* 'EXIT foo' is treated like 'GOTO EXIT!foo'.
    This function converts LABEL into a labal name for EXIT. */

tree
munge_exit_label (label)
     tree label;
{
  return get_identifier3 ("EXIT", "!", IDENTIFIER_POINTER (label));
}

/* Make SAVE_EXPRs as needed, but don't turn a location into a non-location. */

tree
save_if_needed (exp)
tree exp;
{
  return CH_REFERABLE (exp) ? stabilize_reference (exp) : save_expr (exp);
}

/* Return the number of elements in T, which must be a discrete type. */
tree
discrete_count (t)
     tree t;
{
  tree hi = convert (sizetype, TYPE_MAX_VALUE (t));
  if (TYPE_MIN_VALUE (t))
    hi = size_binop (MINUS_EXPR, hi, convert (sizetype, TYPE_MIN_VALUE (t)));
  return size_binop (PLUS_EXPR, hi, integer_one_node);
}