/* pkl-ast.c - Abstract Syntax Tree for Poke.  */

/* Copyright (C) 2019, 2020, 2021, 2022, 2023, 2024, 2025, 2026 Jose E.
 * Marchesi */

/* This program 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 of the License, or
 * (at your option) any later version.
 *
 * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <config.h>

#include <string.h>
#include <assert.h>
#include <stdlib.h>
#include <stdio.h>
#include <inttypes.h>
#include "string-buffer.h"
#include "xalloc.h"
#include "gl_linkedhash_set.h"
#include "gl_xset.h"

#include "pvm.h"
#include "pvm-alloc.h" /* For pvm_{alloc,free}_uncollectable.  */
#include "pk-utils.h"
#include "pkl-ast.h"

/* Note the following macro evaluates the arguments twice!  */
#define MAX(A,B) ((A) > (B) ? (A) : (B))

/* Allocate and return a new AST node, with the given CODE.  The rest
   of the node is initialized to zero.  */

static pkl_ast_node
pkl_ast_make_node (pkl_ast ast,
                   enum pkl_ast_code code)
{
  pkl_ast_node node;

  node = xzalloc (sizeof (union pkl_ast_node));
  PKL_AST_AST (node) = ast;
  PKL_AST_CODE (node) = code;
  PKL_AST_UID (node) = ast->uid++;

  return node;
}

/* Chain AST2 at the end of the tree node chain in AST1.  If AST1 is
   null then it returns AST2.  */

pkl_ast_node
pkl_ast_chainon (pkl_ast_node ast1, pkl_ast_node ast2)
{
  if (ast1)
    {
      pkl_ast_node tmp;

      for (tmp = ast1; PKL_AST_CHAIN (tmp); tmp = PKL_AST_CHAIN (tmp))
        if (tmp == ast2)
          abort ();

      PKL_AST_CHAIN (tmp) = ASTREF (ast2);
      return ast1;
    }

  return ast2;
}

/* Return the number of elements chained by CHAIN starting at the
   given AST node.  */

size_t
pkl_ast_chain_length (pkl_ast_node ast)
{
  pkl_ast_node tmp;
  size_t nelem = 0;

  for (tmp = ast; tmp; tmp = PKL_AST_CHAIN (tmp))
    nelem++;

  return nelem;
}

/* Build and return an AST node for an integer constant.  */

pkl_ast_node
pkl_ast_make_integer (pkl_ast ast,
                      uint64_t value)
{
  pkl_ast_node new = pkl_ast_make_node (ast, PKL_AST_INTEGER);

  PKL_AST_INTEGER_VALUE (new) = value;
  PKL_AST_LITERAL_P (new) = 1;

  return new;
}

/* Build and return an AST node for a string constant.  */

pkl_ast_node
pkl_ast_make_string (pkl_ast ast,
                     const char *str)
{
  pkl_ast_node new = pkl_ast_make_node (ast, PKL_AST_STRING);

  assert (str);

  PKL_AST_STRING_POINTER (new) = xstrdup (str);
  PKL_AST_STRING_LENGTH (new) = strlen (str);
  PKL_AST_LITERAL_P (new) = 1;

  return new;
}

/* Build and return an AST node for an identifier.  */

pkl_ast_node
pkl_ast_make_identifier (pkl_ast ast,
                         const char *str)
{
  pkl_ast_node id = pkl_ast_make_node (ast, PKL_AST_IDENTIFIER);

  PKL_AST_IDENTIFIER_POINTER (id) = xstrdup (str);
  PKL_AST_IDENTIFIER_LENGTH (id) = strlen (str);

  return id;
}

/* Build and return an AST node for an enumerator.  */

pkl_ast_node
pkl_ast_make_enumerator (pkl_ast ast,
                         pkl_ast_node identifier,
                         pkl_ast_node value)
{
  pkl_ast_node enumerator
    = pkl_ast_make_node (ast, PKL_AST_ENUMERATOR);

  assert (identifier != NULL);

  PKL_AST_ENUMERATOR_IDENTIFIER (enumerator) = ASTREF (identifier);
  PKL_AST_ENUMERATOR_VALUE (enumerator) = ASTREF (value);

  return enumerator;
}

/* Build and return an AST node for a conditional expression.  */

pkl_ast_node
pkl_ast_make_cond_exp (pkl_ast ast,
                       pkl_ast_node cond,
                       pkl_ast_node thenexp,
                       pkl_ast_node elseexp)
{
  pkl_ast_node cond_exp
    = pkl_ast_make_node (ast, PKL_AST_COND_EXP);

  assert (cond && thenexp && elseexp);

  PKL_AST_COND_EXP_COND (cond_exp) = ASTREF (cond);
  PKL_AST_COND_EXP_THENEXP (cond_exp) = ASTREF (thenexp);
  PKL_AST_COND_EXP_ELSEEXP (cond_exp) = ASTREF (elseexp);

  PKL_AST_LITERAL_P (cond_exp)
    = PKL_AST_LITERAL_P (thenexp) && PKL_AST_LITERAL_P (elseexp);

  return cond_exp;
}

/* Build and return an AST node for a binary expression.  */

pkl_ast_node
pkl_ast_make_binary_exp (pkl_ast ast,
                         enum pkl_ast_op code,
                         pkl_ast_node op1,
                         pkl_ast_node op2)
{
  pkl_ast_node exp = pkl_ast_make_node (ast, PKL_AST_EXP);

  assert (op1 && op2);

  PKL_AST_EXP_CODE (exp) = code;
  PKL_AST_EXP_ATTR (exp) = PKL_AST_ATTR_NONE;
  PKL_AST_EXP_NUMOPS (exp) = 2;
  PKL_AST_EXP_OPERAND (exp, 0) = ASTREF (op1);
  PKL_AST_EXP_OPERAND (exp, 1) = ASTREF (op2);

  PKL_AST_LITERAL_P (exp)
    = PKL_AST_LITERAL_P (op1) && PKL_AST_LITERAL_P (op2);

  return exp;
}

/* Build and return an AST node for a ternary expression.  */

pkl_ast_node
pkl_ast_make_ternary_exp (pkl_ast ast,
                          enum pkl_ast_op code,
                          pkl_ast_node op1,
                          pkl_ast_node op2,
                          pkl_ast_node op3)
{
  pkl_ast_node exp = pkl_ast_make_node (ast, PKL_AST_EXP);

  PKL_AST_EXP_CODE (exp) = code;
  PKL_AST_EXP_ATTR (exp) = PKL_AST_ATTR_NONE;
  PKL_AST_EXP_NUMOPS (exp) = 3;
  PKL_AST_EXP_OPERAND (exp, 0) = ASTREF (op1);
  PKL_AST_EXP_OPERAND (exp, 1) = ASTREF (op2);
  PKL_AST_EXP_OPERAND (exp, 2) = ASTREF (op3);

  PKL_AST_LITERAL_P (exp)
    = (PKL_AST_LITERAL_P (op1)
       && PKL_AST_LITERAL_P (op2)
       && PKL_AST_LITERAL_P (op3));

  return exp;
}

/* Return the written form of the given attribute code.  This returns
   NULL for PKL_AST_ATTR_NONE */

const char *
pkl_attr_name (enum pkl_ast_attr attr)
{
#define PKL_DEF_ATTR(SYM, STRING) STRING,
  static const char* attr_names[] =
    {
#include "pkl-attrs.def"
     NULL
    };
#undef PKL_DEF_ATTR

  return attr_names[attr];
}

/* Build and return an AST node for an unary expression.  */

pkl_ast_node
pkl_ast_make_unary_exp (pkl_ast ast,
                        enum pkl_ast_op code,
                        pkl_ast_node op)
{
  pkl_ast_node exp = pkl_ast_make_node (ast, PKL_AST_EXP);

  PKL_AST_EXP_CODE (exp) = code;
  PKL_AST_EXP_ATTR (exp) = PKL_AST_ATTR_NONE;
  PKL_AST_EXP_NUMOPS (exp) = 1;
  PKL_AST_EXP_OPERAND (exp, 0) = ASTREF (op);
  PKL_AST_LITERAL_P (exp) = PKL_AST_LITERAL_P (op);

  return exp;
}

/* Build and return an AST node for a function definition.  */

pkl_ast_node
pkl_ast_make_func (pkl_ast ast, pkl_ast_node ret_type,
                   pkl_ast_node args, pkl_ast_node body)
{
  pkl_ast_node func = pkl_ast_make_node (ast, PKL_AST_FUNC);

  assert (body);

  if (ret_type)
    PKL_AST_FUNC_RET_TYPE (func) = ASTREF (ret_type);
  if (args)
    PKL_AST_FUNC_ARGS (func) = ASTREF (args);
  PKL_AST_FUNC_BODY (func) = ASTREF (body);

  PKL_AST_FUNC_FIRST_OPT_ARG (func) = NULL;
  PKL_AST_FUNC_PROGRAM (func) = NULL;

  return func;
}

/* Build and return an AST node for a function definition formal
   argument.  */

pkl_ast_node
pkl_ast_make_func_arg (pkl_ast ast, pkl_ast_node type,
                       pkl_ast_node identifier,
                       pkl_ast_node initial)
{
  pkl_ast_node func_arg = pkl_ast_make_node (ast, PKL_AST_FUNC_ARG);

  assert (identifier);

  PKL_AST_FUNC_ARG_TYPE (func_arg) = ASTREF (type);
  PKL_AST_FUNC_ARG_IDENTIFIER (func_arg) = ASTREF (identifier);
  if (initial)
    PKL_AST_FUNC_ARG_INITIAL (func_arg) = ASTREF (initial);
  PKL_AST_FUNC_ARG_VARARG (func_arg) = 0;

  return func_arg;
}

/* Build and return an AST node for a trimmer.  */

pkl_ast_node
pkl_ast_make_trimmer (pkl_ast ast, pkl_ast_node entity,
                      pkl_ast_node from, pkl_ast_node to,
                      pkl_ast_node addend)
{
  pkl_ast_node trimmer = pkl_ast_make_node (ast, PKL_AST_TRIMMER);

  assert (!to || !addend);

  PKL_AST_TRIMMER_ENTITY (trimmer) = ASTREF (entity);
  if (from)
    PKL_AST_TRIMMER_FROM (trimmer) = ASTREF (from);
  if (to)
    PKL_AST_TRIMMER_TO (trimmer) = ASTREF (to);
  if (addend)
    PKL_AST_TRIMMER_ADDEND (trimmer) = ASTREF (addend);

  return trimmer;
}

/* Build and return an AST node for an indexer.  */

pkl_ast_node
pkl_ast_make_indexer (pkl_ast ast,
                        pkl_ast_node entity, pkl_ast_node index)
{
  pkl_ast_node indexer = pkl_ast_make_node (ast, PKL_AST_INDEXER);

  assert (entity && index);

  PKL_AST_INDEXER_ENTITY (indexer) = ASTREF (entity);
  PKL_AST_INDEXER_INDEX (indexer) = ASTREF (index);
  PKL_AST_LITERAL_P (indexer) = 0;

  return indexer;
}

/* Build and return an AST node for a struct reference.  */

pkl_ast_node
pkl_ast_make_struct_ref (pkl_ast ast,
                         pkl_ast_node sct, pkl_ast_node identifier)
{
  pkl_ast_node sref = pkl_ast_make_node (ast, PKL_AST_STRUCT_REF);

  assert (sct && identifier);

  PKL_AST_STRUCT_REF_STRUCT (sref) = ASTREF (sct);
  PKL_AST_STRUCT_REF_IDENTIFIER (sref) = ASTREF (identifier);

  return sref;
}

/* Build and return type AST nodes.  */

static pkl_ast_node
pkl_ast_make_type (pkl_ast ast)
{
  pkl_ast_node type = pkl_ast_make_node (ast, PKL_AST_TYPE);

  PKL_AST_TYPE_COMPLETE (type)
    = PKL_AST_TYPE_COMPLETE_UNKNOWN;
  PKL_AST_TYPE_FALLIBLE (type)
    = PKL_AST_TYPE_FALLIBLE_UNKNOWN;
  return type;
}

pkl_ast_node
pkl_ast_type_resolv (pkl_ast_node type)
{
  pkl_ast_node t = type;

  while (t && PKL_AST_TYPE_NAME (t))
    t = PKL_AST_TYPE_L_TYPE (t);

  return t;
}

pkl_ast_node
pkl_ast_make_named_type (pkl_ast ast, pkl_ast_node name,
                         pkl_ast_node type)
{
  pkl_ast_node new = pkl_ast_make_type (ast);

  assert (name);

  PKL_AST_TYPE_CODE2 (new) = PKL_TYPE_ALIAS;
  PKL_AST_TYPE_L_NAME (new) = ASTREF (name);
  PKL_AST_TYPE_L_TYPE (new) = ASTREF (type);
  return new;
}

pkl_ast_node
pkl_ast_make_integral_type (pkl_ast ast, size_t size, int signed_p)
{
  pkl_ast_node type = pkl_ast_make_type (ast);

  assert (signed_p == 0 || signed_p == 1);

  PKL_AST_TYPE_CODE (type) = PKL_TYPE_INTEGRAL;
  PKL_AST_TYPE_COMPLETE (type) = PKL_AST_TYPE_COMPLETE_YES;
  PKL_AST_TYPE_FALLIBLE (type) = PKL_AST_TYPE_FALLIBLE_NO;
  PKL_AST_TYPE_I_SIGNED_P (type) = signed_p;
  PKL_AST_TYPE_I_SIZE (type) = size;
  return type;
}

pkl_ast_node
pkl_ast_make_array_type (pkl_ast ast, pkl_ast_node etype, pkl_ast_node bound)
{
  pkl_ast_node type = pkl_ast_make_type (ast);
  const int nclosures
    = 5; /* mapper, writer, bounder, constructor, integrator  */

  assert (etype);

  PKL_AST_TYPE_CODE (type) = PKL_TYPE_ARRAY;
  PKL_AST_TYPE_A_ETYPE (type) = ASTREF (etype);
  if (bound)
    PKL_AST_TYPE_A_BOUND (type) = ASTREF (bound);

  /* Prevent GC to collect these PVM values.  */
  PKL_AST_TYPE_A_CLOSURES (type)
      = pvm_alloc_uncollectable (nclosures * sizeof (pvm_val));
  PKL_AST_TYPE_A_MAPPER (type) = PVM_NULL;
  PKL_AST_TYPE_A_WRITER (type) = PVM_NULL;
  PKL_AST_TYPE_A_BOUNDER (type) = PVM_NULL;
  PKL_AST_TYPE_A_CONSTRUCTOR (type) = PVM_NULL;
  PKL_AST_TYPE_A_INTEGRATOR (type) = PVM_NULL;

  return type;
}

pkl_ast_node
pkl_ast_make_string_type (pkl_ast ast)
{
  pkl_ast_node type = pkl_ast_make_type (ast);

  PKL_AST_TYPE_CODE (type) = PKL_TYPE_STRING;
  PKL_AST_TYPE_COMPLETE (type) = PKL_AST_TYPE_COMPLETE_NO;
  PKL_AST_TYPE_FALLIBLE (type) = PKL_AST_TYPE_FALLIBLE_NO;
  return type;
}

pkl_ast_node
pkl_ast_make_void_type (pkl_ast ast)
{
  pkl_ast_node type = pkl_ast_make_type (ast);

  PKL_AST_TYPE_CODE (type) = PKL_TYPE_VOID;
  PKL_AST_TYPE_COMPLETE (type) = PKL_AST_TYPE_COMPLETE_NO;
  PKL_AST_TYPE_FALLIBLE (type) = PKL_AST_TYPE_FALLIBLE_NO;
  return type;
}

pkl_ast_node
pkl_ast_make_offset_type (pkl_ast ast,
                          pkl_ast_node base_type,
                          pkl_ast_node unit,
                          pkl_ast_node ref_type)
{
  pkl_ast_node type = pkl_ast_make_type (ast);

  assert (base_type && unit);

  PKL_AST_TYPE_CODE (type) = PKL_TYPE_OFFSET;
  PKL_AST_TYPE_COMPLETE (type) = PKL_AST_TYPE_COMPLETE_YES;
  PKL_AST_TYPE_FALLIBLE (type) = PKL_AST_TYPE_FALLIBLE_NO;
  PKL_AST_TYPE_O_UNIT (type) = ASTREF (unit);
  PKL_AST_TYPE_O_BASE_TYPE (type) = ASTREF (base_type);
  if (ref_type)
    PKL_AST_TYPE_O_REF_TYPE (type) = ASTREF (ref_type);

  return type;
}

pkl_ast_node
pkl_ast_make_struct_type (pkl_ast ast,
                          size_t nelem,
                          size_t nfield,
                          size_t ndecl,
                          pkl_ast_node itype,
                          pkl_ast_node struct_type_elems,
                          int pinned_p, int union_p)
{
  pkl_ast_node type = pkl_ast_make_type (ast);
  const int nclosures = 7; /* writer, mapper, constructor, comparator,
                              integrator, deintegrator, typifier.  */

  PKL_AST_TYPE_CODE (type) = PKL_TYPE_STRUCT;
  PKL_AST_TYPE_S_NELEM (type) = nelem;
  PKL_AST_TYPE_S_NFIELD (type) = nfield;
  PKL_AST_TYPE_S_NDECL (type) = ndecl;
  if (struct_type_elems)
    PKL_AST_TYPE_S_ELEMS (type) = ASTREF (struct_type_elems);
  if (itype)
    PKL_AST_TYPE_S_ITYPE (type) = ASTREF (itype);
  PKL_AST_TYPE_S_PINNED_P (type) = pinned_p;
  PKL_AST_TYPE_S_UNION_P (type) = union_p;

  /* Prevent GC to collect these PVM values.  */
  PKL_AST_TYPE_S_CLOSURES (type)
      = pvm_alloc_uncollectable (nclosures * sizeof (pvm_val));
  PKL_AST_TYPE_S_MAPPER (type) = PVM_NULL;
  PKL_AST_TYPE_S_WRITER (type) = PVM_NULL;
  PKL_AST_TYPE_S_CONSTRUCTOR (type) = PVM_NULL;
  PKL_AST_TYPE_S_COMPARATOR (type) = PVM_NULL;
  PKL_AST_TYPE_S_INTEGRATOR (type) = PVM_NULL;
  PKL_AST_TYPE_S_DEINTEGRATOR (type) = PVM_NULL;
  PKL_AST_TYPE_S_TYPIFIER (type) = PVM_NULL;

  return type;
}

pkl_ast_node
pkl_ast_make_struct_type_field (pkl_ast ast,
                                pkl_ast_node name,
                                pkl_ast_node type,
                                pkl_ast_node constraint,
                                pkl_ast_node initializer,
                                pkl_ast_node label,
                                int endian,
                                pkl_ast_node optcond_pre,
                                pkl_ast_node optcond_post)
{
  pkl_ast_node struct_type_elem
    = pkl_ast_make_node (ast, PKL_AST_STRUCT_TYPE_FIELD);

  PKL_AST_STRUCT_TYPE_FIELD_NAME (struct_type_elem)
    = ASTREF (name);
  PKL_AST_STRUCT_TYPE_FIELD_TYPE (struct_type_elem)
    = ASTREF (type);
  if (constraint)
    PKL_AST_STRUCT_TYPE_FIELD_CONSTRAINT (struct_type_elem)
      = ASTREF (constraint);
  if (label)
    PKL_AST_STRUCT_TYPE_FIELD_LABEL (struct_type_elem)
      = ASTREF (label);
  if (optcond_pre)
    PKL_AST_STRUCT_TYPE_FIELD_OPTCOND_PRE (struct_type_elem)
      = ASTREF (optcond_pre);
  if (optcond_post)
    PKL_AST_STRUCT_TYPE_FIELD_OPTCOND_POST (struct_type_elem)
      = ASTREF (optcond_post);
  if (initializer)
    PKL_AST_STRUCT_TYPE_FIELD_INITIALIZER (struct_type_elem)
      = ASTREF (initializer);

  PKL_AST_STRUCT_TYPE_FIELD_ENDIAN (struct_type_elem)
    = endian;

  return struct_type_elem;
}

pkl_ast_node
pkl_ast_make_function_type (pkl_ast ast, pkl_ast_node rtype,
                            size_t narg, pkl_ast_node args)
{
  pkl_ast_node type = pkl_ast_make_type (ast);

  PKL_AST_TYPE_CODE (type) = PKL_TYPE_FUNCTION;
  PKL_AST_TYPE_F_RTYPE (type) = ASTREF (rtype);
  PKL_AST_TYPE_F_NARG (type) = narg;
  PKL_AST_TYPE_F_ARGS (type) = ASTREF (args);
  PKL_AST_TYPE_F_VARARG (type) = 0;
  PKL_AST_TYPE_F_FIRST_OPT_ARG (type) = NULL;

  return type;
}

pkl_ast_node
pkl_ast_make_any_type (pkl_ast ast)
{
  pkl_ast_node type = pkl_ast_make_type (ast);
  PKL_AST_TYPE_CODE (type) = PKL_TYPE_ANY;
  PKL_AST_TYPE_COMPLETE (type) = PKL_AST_TYPE_COMPLETE_NO;
  PKL_AST_TYPE_FALLIBLE (type) = PKL_AST_TYPE_FALLIBLE_YES;
  return type;
}

pkl_ast_node
pkl_ast_make_func_type_arg (pkl_ast ast, pkl_ast_node type,
                            pkl_ast_node name)
{
  pkl_ast_node function_type_arg
    = pkl_ast_make_node (ast, PKL_AST_FUNC_TYPE_ARG);

  PKL_AST_FUNC_TYPE_ARG_TYPE (function_type_arg)
    = ASTREF (type);
  if (name)
    PKL_AST_FUNC_TYPE_ARG_NAME (function_type_arg)
      = ASTREF (name);
  PKL_AST_FUNC_TYPE_ARG_OPTIONAL (function_type_arg) = 0;
  PKL_AST_FUNC_TYPE_ARG_VARARG (function_type_arg) = 0;

  return function_type_arg;
}

/* Allocate and return a duplicated type AST node.  */

pkl_ast_node
pkl_ast_dup_type (pkl_ast_node type)
{
  pkl_ast_node t, new = pkl_ast_make_type (PKL_AST_AST (type));

  PKL_AST_TYPE_CODE (new) = PKL_AST_TYPE_CODE (type);
  PKL_AST_TYPE_COMPLETE (new) = PKL_AST_TYPE_COMPLETE (type);
  PKL_AST_TYPE_FALLIBLE (new) = PKL_AST_TYPE_FALLIBLE (type);

  switch (PKL_AST_TYPE_CODE (type))
    {
    case PKL_TYPE_ANY:
      break;
    case PKL_TYPE_INTEGRAL:
      PKL_AST_TYPE_I_SIZE (new) = PKL_AST_TYPE_I_SIZE (type);
      PKL_AST_TYPE_I_SIGNED_P (new) = PKL_AST_TYPE_I_SIGNED_P (type);
      PKL_AST_TYPE_I_DYN_P (new) = PKL_AST_TYPE_I_DYN_P (type);
      break;
    case PKL_TYPE_ARRAY:
      {
        pkl_ast_node etype
          = pkl_ast_dup_type (PKL_AST_TYPE_A_ETYPE (type));
        PKL_AST_TYPE_A_BOUND (new) = ASTREF (PKL_AST_TYPE_A_BOUND (type));
        PKL_AST_TYPE_A_ETYPE (new) = ASTREF (etype);
      }
      break;
    case PKL_TYPE_STRUCT:
      PKL_AST_TYPE_S_NELEM (new) = PKL_AST_TYPE_S_NELEM (type);
      PKL_AST_TYPE_S_NFIELD (new) = PKL_AST_TYPE_S_NFIELD (type);
      PKL_AST_TYPE_S_NCFIELD (new) = PKL_AST_TYPE_S_NCFIELD (type);
      PKL_AST_TYPE_S_NDECL (new) = PKL_AST_TYPE_S_NDECL (type);
      for (t = PKL_AST_TYPE_S_ELEMS (type); t; t = PKL_AST_CHAIN (t))
        {
          pkl_ast_node struct_type_elem_name;
          pkl_ast_node struct_type_elem_type;
          pkl_ast_node struct_type_elem_size;
          pkl_ast_node struct_type_elem_constraint;
          char *struct_type_elem_constraint_src;
          pkl_ast_node struct_type_elem_initializer;
          pkl_ast_node struct_type_elem_label;
          pkl_ast_node new_struct_type_elem_name;
          pkl_ast_node struct_type_elem;
          pkl_ast_node struct_type_elem_optcond_pre;
          pkl_ast_node struct_type_elem_optcond_post;
          int struct_type_elem_endian;
          int struct_type_elem_computed_p;

          /* Process only struct type fields.  XXX But what about
             declarations?  These should also be duplicated.  */
          if (PKL_AST_CODE (t) != PKL_AST_STRUCT_TYPE_FIELD)
            break;

          struct_type_elem_name = PKL_AST_STRUCT_TYPE_FIELD_NAME (t);
          struct_type_elem_type = PKL_AST_STRUCT_TYPE_FIELD_TYPE (t);
          struct_type_elem_size = PKL_AST_STRUCT_TYPE_FIELD_SIZE (t);
          struct_type_elem_constraint = PKL_AST_STRUCT_TYPE_FIELD_CONSTRAINT (t);
          struct_type_elem_constraint_src
            = (PKL_AST_STRUCT_TYPE_FIELD_CONSTRAINT_SRC (t)
               ? xstrdup (PKL_AST_STRUCT_TYPE_FIELD_CONSTRAINT_SRC (t))
               : NULL);
          struct_type_elem_initializer = PKL_AST_STRUCT_TYPE_FIELD_INITIALIZER (t);
          struct_type_elem_label = PKL_AST_STRUCT_TYPE_FIELD_LABEL (t);
          struct_type_elem_endian = PKL_AST_STRUCT_TYPE_FIELD_ENDIAN (t);
          struct_type_elem_optcond_pre = PKL_AST_STRUCT_TYPE_FIELD_OPTCOND_PRE (t);
          struct_type_elem_optcond_post = PKL_AST_STRUCT_TYPE_FIELD_OPTCOND_POST (t);
          struct_type_elem_computed_p = PKL_AST_STRUCT_TYPE_FIELD_COMPUTED_P (t);

          new_struct_type_elem_name
            = (struct_type_elem_name
               ? pkl_ast_make_identifier (PKL_AST_AST (new),
                                          PKL_AST_IDENTIFIER_POINTER (struct_type_elem_name))
               : NULL);
          struct_type_elem
            = pkl_ast_make_struct_type_field (PKL_AST_AST (new),
                                              new_struct_type_elem_name,
                                              pkl_ast_dup_type (struct_type_elem_type),
                                              struct_type_elem_constraint,
                                              struct_type_elem_initializer,
                                              struct_type_elem_label,
                                              struct_type_elem_endian,
                                              struct_type_elem_optcond_pre,
                                              struct_type_elem_optcond_post);

          PKL_AST_STRUCT_TYPE_FIELD_CONSTRAINT_SRC (struct_type_elem)
            = struct_type_elem_constraint_src;
          PKL_AST_STRUCT_TYPE_FIELD_COMPUTED_P (struct_type_elem)
            = struct_type_elem_computed_p;
          PKL_AST_STRUCT_TYPE_FIELD_SIZE (struct_type_elem)
            = ASTREF (struct_type_elem_size);
          PKL_AST_TYPE_S_ELEMS (new)
            = pkl_ast_chainon (PKL_AST_TYPE_S_ELEMS (new),
                               struct_type_elem);
          PKL_AST_TYPE_S_ELEMS (new) = ASTREF (PKL_AST_TYPE_S_ELEMS (type));
          PKL_AST_TYPE_S_PINNED_P (new) = PKL_AST_TYPE_S_PINNED_P (type);
          PKL_AST_TYPE_S_UNION_P (new) = PKL_AST_TYPE_S_UNION_P (type);
        }
      break;
    case PKL_TYPE_FUNCTION:
      PKL_AST_TYPE_F_RTYPE (new)
        = pkl_ast_dup_type (PKL_AST_TYPE_F_RTYPE (type));
      PKL_AST_TYPE_F_NARG (new) = PKL_AST_TYPE_F_NARG (type);
      for (t = PKL_AST_TYPE_F_ARGS (type); t; t = PKL_AST_CHAIN (t))
        {
          pkl_ast_node fun_type_arg_type
            = PKL_AST_FUNC_TYPE_ARG_TYPE (t);
          pkl_ast_node fun_type_arg_name
            = PKL_AST_FUNC_TYPE_ARG_NAME (t);

          pkl_ast_node function_type_arg
            = pkl_ast_make_func_type_arg (PKL_AST_AST (new),
                                          fun_type_arg_type,
                                          fun_type_arg_name);
          PKL_AST_FUNC_TYPE_ARG_OPTIONAL (function_type_arg)
            = PKL_AST_FUNC_TYPE_ARG_OPTIONAL (t);
          PKL_AST_FUNC_TYPE_ARG_VARARG (function_type_arg)
            = PKL_AST_FUNC_TYPE_ARG_VARARG (t);
          PKL_AST_TYPE_F_ARGS (new)
            = pkl_ast_chainon (PKL_AST_TYPE_F_ARGS (new),
                               function_type_arg);
          PKL_AST_TYPE_F_ARGS (new) = ASTREF (PKL_AST_TYPE_F_ARGS (t));
        }
      PKL_AST_TYPE_F_FIRST_OPT_ARG (new)
        = ASTREF (PKL_AST_TYPE_F_FIRST_OPT_ARG (type));
      PKL_AST_TYPE_F_VARARG (new)
        = PKL_AST_TYPE_F_VARARG (type);
      break;
    case PKL_TYPE_OFFSET:
      /* Fallthrough.  */
    case PKL_TYPE_STRING:
      /* Fallthrough.  */
    default:
      break;
    }

  return new;
}

/* Given a struct type node AST and a string in the form BB.CC.CC.xx,
   check that the intermediate fields are valid struct references, and return
   the pkl_ast_node corresponding to the type of the latest field CC. */

pkl_ast_node
pkl_struct_type_traverse (pkl_ast_node type, const char *path)
{
  char *trunk, *sub, *base, *strtok_ptr;

  if (PKL_AST_TYPE_CODE (type) != PKL_TYPE_STRUCT)
    return NULL;

  trunk = strndup (path, strlen (path) - strlen (strrchr (path, '.')));
  base = strtok_r (trunk, ".", &strtok_ptr);

  /* Node in the form XX. Check to silence the compiler about base not used */
  if (base == NULL)
    {
      free (trunk);
      return type;
    }

  while ((sub = strtok_r (NULL, ".", &strtok_ptr)) != NULL)
    {
      pkl_ast_node ename;
      pkl_ast_node etype, t;
      char *field;

      etype = NULL;

      if (PKL_AST_TYPE_CODE (type) != PKL_TYPE_STRUCT)
        goto out;

      for (t = PKL_AST_TYPE_S_ELEMS (type); t;
           t = PKL_AST_CHAIN (t))
        {
          if (PKL_AST_CODE (t) == PKL_AST_STRUCT_TYPE_FIELD)
            {
              ename = PKL_AST_STRUCT_TYPE_FIELD_NAME (t);

              if (ename == NULL)
                continue;

              etype = PKL_AST_STRUCT_TYPE_FIELD_TYPE (t);

              field = PKL_AST_IDENTIFIER_POINTER (ename);

              if (STREQ (field, sub))
                {
                  type = etype;
                  break;
                }
            }
        }

      if (type != etype)
        goto out;
    }

  free (trunk);
  return type;

out:
  free (trunk);
  return NULL;
}

/* Given two integral types, build an return a "promoted" integral
   type derived from the arguments.  The promotion follows these
   rules:

   - If TYPE1 or TYPE2 are signed, the promoted type is also
     signed.  Otherwise it is unsigned.

   - The size of the promoted type is the max of the size of TYPE1 and
     TYPE2.
*/

pkl_ast_node
pkl_type_integral_promote (pkl_ast ast, pkl_ast_node type1,
                           pkl_ast_node type2)
{
  int signed_p;
  int size;

  assert (PKL_AST_TYPE_CODE (type1) == PKL_TYPE_INTEGRAL
          && PKL_AST_TYPE_CODE (type2) == PKL_TYPE_INTEGRAL);

  signed_p = (PKL_AST_TYPE_I_SIGNED_P (type1)
              && PKL_AST_TYPE_I_SIGNED_P (type2));
  size = MAX (PKL_AST_TYPE_I_SIZE (type1),
              PKL_AST_TYPE_I_SIZE (type2));

  return pkl_ast_make_integral_type (ast, size, signed_p);
}

/* Return whether the given type AST node corresponds to an exception
   type.  */

int
pkl_ast_type_is_exception (pkl_ast_node type)
{
  pkl_ast_node type_name;

  assert (PKL_AST_CODE (type) == PKL_AST_TYPE);

  type_name = PKL_AST_TYPE_NAME (type);
  return (PKL_AST_TYPE_CODE (type) == PKL_TYPE_STRUCT
          && type_name
          && STREQ (PKL_AST_IDENTIFIER_POINTER (type_name), "Exception"));
}

/* Remove bounder closures from the given array type.  This works
   recursively for arrays of arrays.  */

void
pkl_ast_array_type_remove_bounders (pkl_ast_node type)
{
  pkl_ast_node etype;

  assert (PKL_AST_TYPE_CODE (type) == PKL_TYPE_ARRAY);

  PKL_AST_TYPE_A_BOUNDER (type) = PVM_NULL;

  for (etype = PKL_AST_TYPE_A_ETYPE (type);
       PKL_AST_TYPE_CODE (etype) == PKL_TYPE_ARRAY
         && PKL_AST_TYPE_NAME (etype) == NULL;
       etype = PKL_AST_TYPE_A_ETYPE (etype))
    {
      PKL_AST_TYPE_A_BOUNDER (etype) = PVM_NULL;
    }
}

/* Return whether two given type AST nodes are equal, i.e. they denote
   the same type.  */

int
pkl_ast_type_equal_p (pkl_ast_node a, pkl_ast_node b)
{
  if (PKL_AST_TYPE_CODE (a) != PKL_AST_TYPE_CODE (b))
    return 0;

  switch (PKL_AST_TYPE_CODE (a))
    {
    case PKL_TYPE_ANY:
      return 1;
      break;
    case PKL_TYPE_INTEGRAL:
      return (PKL_AST_TYPE_I_SIZE (a) == PKL_AST_TYPE_I_SIZE (b)
              && PKL_AST_TYPE_I_SIGNED_P (a) == PKL_AST_TYPE_I_SIGNED_P (b));
      break;
    case PKL_TYPE_ARRAY:
      {
        /* If the array types denote static arrays, i.e. the array
           types are bounded by a _constant_ number of elements then
           we can actually do some control here.  */
        pkl_ast_node ba = PKL_AST_TYPE_A_BOUND (a);
        pkl_ast_node bb = PKL_AST_TYPE_A_BOUND (b);

        if (ba && bb)
          {
            pkl_ast_node tba = PKL_AST_TYPE (ba);
            pkl_ast_node tbb = PKL_AST_TYPE (bb);

            if (PKL_AST_TYPE_CODE (tba) == PKL_TYPE_INTEGRAL
                && PKL_AST_CODE (ba) == PKL_AST_INTEGER
                && PKL_AST_TYPE_CODE (tbb) == PKL_TYPE_INTEGRAL
                && PKL_AST_CODE (bb) == PKL_AST_INTEGER)
              {
                if (PKL_AST_INTEGER_VALUE (ba)
                    != PKL_AST_INTEGER_VALUE (bb))
                  return 0;
              }
          }

        return pkl_ast_type_equal_p (PKL_AST_TYPE_A_ETYPE (a),
                                     PKL_AST_TYPE_A_ETYPE (b));
        break;
      }
    case PKL_TYPE_STRUCT:
      {
        /* Anonymous structs are always unequal.  */
        if (PKL_AST_TYPE_NAME (a) == NULL || PKL_AST_TYPE_NAME (b) == NULL)
          return 0;

        /* Struct types are compared by name.  */
        return (STREQ (PKL_AST_IDENTIFIER_POINTER (PKL_AST_TYPE_NAME (a)),
                       PKL_AST_IDENTIFIER_POINTER (PKL_AST_TYPE_NAME (b))));
        break;
      }
    case PKL_TYPE_FUNCTION:
      {
        pkl_ast_node fa, fb;

        if (PKL_AST_TYPE_F_NARG (a) != PKL_AST_TYPE_F_NARG (b))
          return 0;
        for (fa = PKL_AST_TYPE_F_ARGS (a), fb = PKL_AST_TYPE_F_ARGS (b);
             fa && fb;
             fa = PKL_AST_CHAIN (fa), fb = PKL_AST_CHAIN (fb))
          {
            if (PKL_AST_FUNC_TYPE_ARG_OPTIONAL (fa)
                != PKL_AST_FUNC_TYPE_ARG_OPTIONAL (fb))
              return 0;

            if (PKL_AST_FUNC_TYPE_ARG_VARARG (fa)
                != PKL_AST_FUNC_TYPE_ARG_VARARG (fb))
              return 0;

            if (!pkl_ast_type_equal_p (PKL_AST_FUNC_TYPE_ARG_TYPE (fa),
                                       PKL_AST_FUNC_TYPE_ARG_TYPE (fb)))
              return 0;
          }
        break;
      }
    case PKL_TYPE_OFFSET:
      {
        pkl_ast_node a_unit = PKL_AST_TYPE_O_UNIT (a);
        pkl_ast_node b_unit = PKL_AST_TYPE_O_UNIT (b);
        pkl_ast_node a_ref_type = PKL_AST_TYPE_O_REF_TYPE (a);
        pkl_ast_node b_ref_type = PKL_AST_TYPE_O_REF_TYPE (b);

        /* If the units of the types are not known yet (because they
           are identifiers, or whatever then we cannot guarantee the
           types are the same.  */
        if (PKL_AST_CODE (a_unit) != PKL_AST_INTEGER
            || PKL_AST_CODE (b_unit) != PKL_AST_INTEGER)
          return 0;

        /* Offset types having different referred types are not
           equal.  */
        if (!((a_ref_type == NULL && b_ref_type == NULL)
              || (a_ref_type
                  && b_ref_type
                  && pkl_ast_type_equal_p (a_ref_type, b_ref_type))))
          return 0;

        return (PKL_AST_INTEGER_VALUE (a_unit) == PKL_AST_INTEGER_VALUE (b_unit)
                  && pkl_ast_type_equal_p (PKL_AST_TYPE_O_BASE_TYPE (a),
                                           PKL_AST_TYPE_O_BASE_TYPE (b)));
      }
      break;
    case PKL_TYPE_STRING:
      /* Fallthrough.  */
    default:
      break;
    }

  return 1;
}

/* Return whether the type FT is promoteable to type TT.  Note that,
   unlike pkl_ast_type_equal_p above, this operation is not
   generally commutative.  */

int
pkl_ast_type_promoteable_p (pkl_ast_node ft, pkl_ast_node tt,
                            int promote_array_of_any)
{
  if (pkl_ast_type_equal_p (ft, tt))
    return 1;

  /* VOID can't be promoted to anything.  */
  if (PKL_AST_TYPE_CODE (ft) == PKL_TYPE_VOID)
    return 0;

  /* Any type is promoteable to ANY.  */
  if (PKL_AST_TYPE_CODE (tt) == PKL_TYPE_ANY)
    return 1;

  /* An integral type is promoteable to other integral types.  */
  if (PKL_AST_TYPE_CODE (tt) == PKL_TYPE_INTEGRAL
      && PKL_AST_TYPE_CODE (ft) == PKL_TYPE_INTEGRAL)
    return 1;

  /* An offset type is promoteable to other offset types.  */
  if (PKL_AST_TYPE_CODE (tt) == PKL_TYPE_OFFSET
      && PKL_AST_TYPE_CODE (ft) == PKL_TYPE_OFFSET)
    return 1;

  /* Any array[] type is promoteable to ANY[].  */
  if (promote_array_of_any
      && PKL_AST_TYPE_CODE (ft) == PKL_TYPE_ARRAY
      && PKL_AST_TYPE_CODE (tt) == PKL_TYPE_ARRAY
      && PKL_AST_TYPE_CODE (PKL_AST_TYPE_A_ETYPE (tt)) == PKL_TYPE_ANY)
    return 1;

  /* An array type is promoteable to other array type if the types of
     the elements are equal.  Only length may differ.  */
  if (PKL_AST_TYPE_CODE (ft) == PKL_TYPE_ARRAY
      && PKL_AST_TYPE_CODE (tt) == PKL_TYPE_ARRAY)
    {
      pkl_ast_node ft_bound = PKL_AST_TYPE_A_BOUND (ft);
      pkl_ast_node tt_bound = PKL_AST_TYPE_A_BOUND (tt);
      pkl_ast_node ft_etype = PKL_AST_TYPE_A_ETYPE (ft);
      pkl_ast_node tt_etype = PKL_AST_TYPE_A_ETYPE (tt);

      if (!pkl_ast_type_equal_p (tt_etype, ft_etype))
        return 0;

      /* Static array types can be handled here.  */
      if (tt_bound && (PKL_AST_CODE (tt_bound) == PKL_AST_INTEGER))
        {
          if (!ft_bound || PKL_AST_CODE (ft_bound) != PKL_AST_INTEGER)
            return 0;

          if (PKL_AST_INTEGER_VALUE (ft_bound)
              != PKL_AST_INTEGER_VALUE (tt_bound))
            return 0;
        }

      return 1;
      //      return pkl_ast_type_promoteable_p (PKL_AST_TYPE_A_ETYPE (ft),
      //                                         PKL_AST_TYPE_A_ETYPE (tt),
      //                                         promote_array_of_any);
    }

  /* A struct type is promoteable to any integral type if the struct
     itself is integral.  */
  if (PKL_AST_TYPE_CODE (ft) == PKL_TYPE_STRUCT
      && PKL_AST_TYPE_S_ITYPE (ft)
      && PKL_AST_TYPE_CODE (tt) == PKL_TYPE_INTEGRAL)
    return 1;

  return 0;
}

/* Return whether the type TYPE is integrable or not.  */

int
pkl_ast_type_integrable_p (pkl_ast_node type)
{
  if (PKL_AST_TYPE_CODE (type) == PKL_TYPE_INTEGRAL)
    return 1;
  if (PKL_AST_TYPE_CODE (type) == PKL_TYPE_ARRAY)
    return pkl_ast_type_integrable_p (PKL_AST_TYPE_A_ETYPE (type));
  /* Integral structs are integrable.  */
  if (PKL_AST_TYPE_CODE (type) == PKL_TYPE_STRUCT
      && PKL_AST_TYPE_S_ITYPE (type) != NULL)
    return 1;
  return 0;
}

/* Build and return an expression that computes the size of TYPE in
   bits, as an unsigned 64-bit value.

   Note that it is required for the returned expression to not trigger
   errors in the fold pass, i.e. no division by zero, no overflow, out
   of bound indexes.  This will be detected by a run-time
   abort/assert.  */

pkl_ast_node
pkl_ast_sizeof_type (pkl_ast ast, pkl_ast_node type)
{
  pkl_ast_node res;
  pkl_ast_node res_type
    = pkl_ast_make_integral_type (ast, 64, 0);

  /* This function should only be called on complete types.  */
  assert (PKL_AST_TYPE_COMPLETE (type)
          == PKL_AST_TYPE_COMPLETE_YES);

  switch (PKL_AST_TYPE_CODE (type))
    {
    case PKL_TYPE_INTEGRAL:
      {
        res = pkl_ast_make_integer (ast, PKL_AST_TYPE_I_SIZE (type));
        PKL_AST_TYPE (res) = ASTREF (res_type);
        break;
      }
    case PKL_TYPE_ARRAY:
      {
        pkl_ast_node bound = PKL_AST_TYPE_A_BOUND (type);
        pkl_ast_node bound_type = PKL_AST_TYPE (bound);
        pkl_ast_node sizeof_etype
          = pkl_ast_sizeof_type (ast,
                                 PKL_AST_TYPE_A_ETYPE (type));

        if (PKL_AST_TYPE_CODE (bound_type) == PKL_TYPE_INTEGRAL)
          res = pkl_ast_make_binary_exp (ast, PKL_AST_OP_MUL,
                                         bound, sizeof_etype);
        else if (PKL_AST_TYPE_CODE (bound_type) == PKL_TYPE_OFFSET)
          {
            pkl_ast_node mag, unit;

            assert (PKL_AST_CODE (bound) == PKL_AST_OFFSET);
            mag = PKL_AST_OFFSET_MAGNITUDE (bound);
            unit = PKL_AST_OFFSET_UNIT (bound);
            res = pkl_ast_make_integer (ast,
                                        PKL_AST_INTEGER_VALUE (mag)
                                          * PKL_AST_INTEGER_VALUE (unit));
          }
        else
          PK_UNREACHABLE ();
        PKL_AST_TYPE (res) = ASTREF (res_type);
        break;
      }
    case PKL_TYPE_STRUCT:
      {
        pkl_ast_node t;

        res = pkl_ast_make_integer (ast, 0);
        PKL_AST_TYPE (res) = ASTREF (res_type);

        for (t = PKL_AST_TYPE_S_ELEMS (type); t; t = PKL_AST_CHAIN (t))
          {
            pkl_ast_node field_label;
            pkl_ast_node elem_type_size;

            if (PKL_AST_CODE (t) != PKL_AST_STRUCT_TYPE_FIELD
                || PKL_AST_STRUCT_TYPE_FIELD_COMPUTED_P (t))
              continue;

            field_label = PKL_AST_STRUCT_TYPE_FIELD_LABEL (t);
            elem_type_size = PKL_AST_STRUCT_TYPE_FIELD_SIZE (t);

            assert (elem_type_size != NULL);

            /* Struct fields with non-constant labels are not
               expected, as these cannot appear in complete struct
               types.  Ditto for optional fields.  */
            assert (field_label == NULL
                    || PKL_AST_CODE (field_label) == PKL_AST_OFFSET);
            assert (PKL_AST_STRUCT_TYPE_FIELD_OPTCOND_PRE (t) == NULL);
            assert (PKL_AST_STRUCT_TYPE_FIELD_OPTCOND_POST (t) == NULL);

            /* All fields of a complete union have the same size.
               If struct is pinned, the new size is
               `max (size, elem_type_size)`.
               Otherwise if the field has a constant label, the new size
               is `max (size, label_in_bits + elem_type_size)'.
               Otherwise, it is `size + elem_type_size'.  */
            if (PKL_AST_TYPE_S_UNION_P (type))
              {
                res = ASTREF (elem_type_size);
                PKL_AST_TYPE (res) = ASTREF (res_type);
                break;
              }
            else if (PKL_AST_TYPE_S_PINNED_P (type))
              {
                pkl_ast_node cond;

                cond = pkl_ast_make_binary_exp (ast, PKL_AST_OP_GT,
                                                elem_type_size, res);
                PKL_AST_TYPE (cond) = ASTREF (res_type);

                res = pkl_ast_make_cond_exp (ast, cond, elem_type_size, res);
                PKL_AST_TYPE (res) = ASTREF (res_type);
              }
            else if (field_label)
              {
                pkl_ast_node label_magnitude, label_in_bits, cond;
                pkl_ast_node off_in_bits;

                label_magnitude
                  = pkl_ast_make_cast (ast, res_type,
                                       PKL_AST_OFFSET_MAGNITUDE (field_label));
                PKL_AST_TYPE (label_magnitude) = ASTREF (res_type);

                label_in_bits
                  = pkl_ast_make_binary_exp (ast, PKL_AST_OP_MUL,
                                             label_magnitude,
                                             PKL_AST_OFFSET_UNIT (field_label));
                PKL_AST_TYPE (label_in_bits) = ASTREF (res_type);

                off_in_bits = pkl_ast_make_binary_exp (ast, PKL_AST_OP_ADD,
                                                       label_in_bits,
                                                       elem_type_size);
                PKL_AST_TYPE (off_in_bits) = ASTREF (res_type);

                cond = pkl_ast_make_binary_exp (ast, PKL_AST_OP_GT,
                                                res, off_in_bits);
                PKL_AST_TYPE (cond) = ASTREF (res_type);

                res = pkl_ast_make_cond_exp (ast, cond, res, off_in_bits);
                PKL_AST_TYPE (res) = ASTREF (res_type);
              }
            else
              {
                /* Add the size of the field to the accumulated size.  */
                res = pkl_ast_make_binary_exp (ast, PKL_AST_OP_ADD,
                                               res, elem_type_size);
                PKL_AST_TYPE (res) = ASTREF (res_type);
              }
          }

        break;
      }
    case PKL_TYPE_FUNCTION:
      {
        /* By convention functions have sizeof 0#b  */
        res = pkl_ast_make_integer (ast, 0);
        PKL_AST_TYPE (res) = ASTREF (res_type);
        break;
      }
    case PKL_TYPE_OFFSET:
      return pkl_ast_sizeof_type (ast, PKL_AST_TYPE_O_BASE_TYPE (type));
      break;
    case PKL_TYPE_STRING:
    default:
      PK_UNREACHABLE ();
      break;
    }

  return res;
}

/* Return the size (in bits) of values of the given type, which must
   be an integral, offset or integral struct type.  */

size_t
pkl_ast_sizeof_integral_type (pkl_ast_node type)
{
  if (PKL_AST_TYPE_CODE (type) == PKL_TYPE_INTEGRAL)
    return PKL_AST_TYPE_I_SIZE (type);
  else if (PKL_AST_TYPE_CODE (type) == PKL_TYPE_OFFSET)
    {
      pkl_ast_node base_type = PKL_AST_TYPE_O_BASE_TYPE (type);
      return PKL_AST_TYPE_I_SIZE (base_type);
    }
  else if (PKL_AST_TYPE_CODE (type) == PKL_TYPE_STRUCT
           && PKL_AST_TYPE_S_ITYPE (type) != NULL)
    {
      pkl_ast_node itype = PKL_AST_TYPE_S_ITYPE (type);
      return PKL_AST_TYPE_I_SIZE (itype);
    }
  else
    PK_UNREACHABLE ();
}

/* Return 1 if the given TYPE can be mapped in IO.  0 otherwise.  */

int
pkl_ast_type_mappable_p (pkl_ast_node type)
{
  switch (PKL_AST_TYPE_CODE (type))
    {
    case PKL_TYPE_INTEGRAL:
    case PKL_TYPE_STRING:
    case PKL_TYPE_OFFSET:
    case PKL_TYPE_FUNCTION:
      return 1;
    case PKL_TYPE_ARRAY:
      return pkl_ast_type_mappable_p (PKL_AST_TYPE_A_ETYPE (type));
      break;
    case PKL_TYPE_STRUCT:
      {
        pkl_ast_node elem;

        for (elem = PKL_AST_TYPE_S_ELEMS (type);
             elem;
             elem = PKL_AST_CHAIN (elem))
          {
            if (PKL_AST_CODE (elem) == PKL_AST_STRUCT_TYPE_FIELD
                && !PKL_AST_STRUCT_TYPE_FIELD_COMPUTED_P (elem)
                && !pkl_ast_type_mappable_p (PKL_AST_STRUCT_TYPE_FIELD_TYPE (elem)))
              return 0;
          }

        return 1;
        break;
      }
    default:
      break;
    }

  return 0;
}

/* Return PKL_AST_TYPE_FALLIBLE_YES if the given TYPE is fallible.
   Return PKL_AST_TYPE_FALLIBLE_NO otherwise.  */

int
pkl_ast_type_is_fallible (pkl_ast_node type)
{
  int fallible = PKL_AST_TYPE_FALLIBLE_UNKNOWN;

  /* The failability may have already be determined.  */
  if (PKL_AST_TYPE_FALLIBLE (type) != PKL_AST_TYPE_FALLIBLE_UNKNOWN)
    return PKL_AST_TYPE_FALLIBLE (type);

  switch (PKL_AST_TYPE_CODE (type))
    {
      /* Certain types are never fallible.  */
    case PKL_TYPE_INTEGRAL:
    case PKL_TYPE_OFFSET:
    case PKL_TYPE_FUNCTION:
    case PKL_TYPE_STRING:
    case PKL_TYPE_VOID:
      fallible = PKL_AST_TYPE_FALLIBLE_NO;
      break;
      /* Certain other types are always fallible.  */
    case PKL_TYPE_ANY:
      fallible = PKL_AST_TYPE_FALLIBLE_YES;
      break;
      /* Structs may or not be fallible.  */
    case PKL_TYPE_STRUCT:
      {
        pkl_ast_node elem;

        fallible = PKL_AST_TYPE_FALLIBLE_NO;

        /* Unions are always fallible. */
        if (PKL_AST_TYPE_S_UNION_P (type))
          {
            fallible = PKL_AST_TYPE_FALLIBLE_YES;
            break;
          }

        /* If any of the field types is fallible, or if any of the
           fields have constraint expressions, then the struct type is
           fallible.  */
        for (elem = PKL_AST_TYPE_S_ELEMS (type);
             elem;
             elem = PKL_AST_CHAIN (elem))
          {
            pkl_ast_node elem_type;

            if (PKL_AST_CODE (elem) != PKL_AST_STRUCT_TYPE_FIELD
                || PKL_AST_STRUCT_TYPE_FIELD_COMPUTED_P (elem))
              continue;

            elem_type = PKL_AST_STRUCT_TYPE_FIELD_TYPE (elem);
            if (pkl_ast_type_is_fallible (elem_type)
                || PKL_AST_STRUCT_TYPE_FIELD_CONSTRAINT (elem) != NULL)
              {
                fallible = PKL_AST_TYPE_FALLIBLE_YES;
                break;
              }
          }
        break;
      }
      /* Array types are fallible if their element type is
         fallible.  */
    case PKL_TYPE_ARRAY:
      fallible = pkl_ast_type_is_fallible (PKL_AST_TYPE_A_ETYPE (type));
      break;
    default:
      break;
    }

  assert (fallible != PKL_AST_TYPE_FALLIBLE_UNKNOWN);
  return fallible;
}

/* Return PKL_AST_TYPE_COMPLETE_YES if the given TYPE is a complete
   type.  Return PKL_AST_TYPE_COMPLETE_NO otherwise.  */

int
pkl_ast_type_is_complete (pkl_ast_node type)
{
  int complete = PKL_AST_TYPE_COMPLETE_UNKNOWN;

  /* The type completeness may have already be determined.  */
  if (PKL_AST_TYPE_COMPLETE (type) != PKL_AST_TYPE_COMPLETE_UNKNOWN)
    return PKL_AST_TYPE_COMPLETE (type);

  switch (PKL_AST_TYPE_CODE (type))
    {
      /* Integral, offset and function types are always complete.  */
    case PKL_TYPE_INTEGRAL:
    case PKL_TYPE_OFFSET:
    case PKL_TYPE_FUNCTION:
      complete = PKL_AST_TYPE_COMPLETE_YES;
      break;
      /* Other types are never complete.  */
    case PKL_TYPE_ANY:
    case PKL_TYPE_VOID:
    case PKL_TYPE_STRING:
      complete = PKL_AST_TYPE_COMPLETE_NO;
      break;
      /* Struct types are complete if their fields are also of
         complete types and there are non-constant labels nor
         optconds.  */
    case PKL_TYPE_STRUCT:
      {
        pkl_ast_node elem;

        complete = PKL_AST_TYPE_COMPLETE_YES;
        for (elem = PKL_AST_TYPE_S_ELEMS (type);
             elem;
             elem = PKL_AST_CHAIN (elem))
          {
            pkl_ast_node elem_label;
            pkl_ast_node elem_type;

            if (PKL_AST_CODE (elem) != PKL_AST_STRUCT_TYPE_FIELD
                || PKL_AST_STRUCT_TYPE_FIELD_COMPUTED_P (elem))
              continue;

            elem_label = PKL_AST_STRUCT_TYPE_FIELD_LABEL (elem);
            elem_type = PKL_AST_STRUCT_TYPE_FIELD_TYPE (elem);
            if ((elem_label && PKL_AST_CODE (elem_label) != PKL_AST_OFFSET)
                 || PKL_AST_STRUCT_TYPE_FIELD_OPTCOND_PRE (elem)
                || PKL_AST_STRUCT_TYPE_FIELD_OPTCOND_POST (elem)
                 || (pkl_ast_type_is_complete (elem_type)
                       == PKL_AST_TYPE_COMPLETE_NO))
              {
                complete = PKL_AST_TYPE_COMPLETE_NO;
                break;
              }
          }
        /* This is a union type with complete fields. This type is
           complete if all fields have the same size.  */
        if (complete == PKL_AST_TYPE_COMPLETE_YES && PKL_AST_TYPE_S_UNION_P (type))
          {
            pkl_ast_node size_node;
            size_t size = -1;

            for (elem = PKL_AST_TYPE_S_ELEMS (type);
                 elem;
                 elem = PKL_AST_CHAIN (elem))
              {
                if (PKL_AST_CODE (elem) != PKL_AST_STRUCT_TYPE_FIELD
                    || PKL_AST_STRUCT_TYPE_FIELD_COMPUTED_P (elem))
                  continue;

                size_node = PKL_AST_STRUCT_TYPE_FIELD_SIZE (elem);
                assert (size_node);
                assert (PKL_AST_TYPE_CODE (PKL_AST_TYPE (size_node))
                        == PKL_TYPE_INTEGRAL);
                if (size == -1)
                  size = PKL_AST_INTEGER_VALUE (size_node);
                else if (PKL_AST_INTEGER_VALUE (size_node) != size)
                  {
                    complete = PKL_AST_TYPE_COMPLETE_NO;
                    break;
                  }
              }
          }
        break;
      }
      /* Array types are complete if the number of elements in the
         array are specified and it is a literal expression; and type
         of elements is also complete.  */
    case PKL_TYPE_ARRAY:
      {
        pkl_ast_node bound = PKL_AST_TYPE_A_BOUND (type);

        if (bound)
          {
            pkl_ast_node bound_type = PKL_AST_TYPE (bound);

            /* The type of the bounding expression should have been
               calculated at this point.  */
            assert (bound_type);

            if ((PKL_AST_TYPE_CODE (bound_type) == PKL_TYPE_INTEGRAL
                 || PKL_AST_TYPE_CODE (bound_type) == PKL_TYPE_OFFSET)
                && PKL_AST_LITERAL_P (bound))
              complete = pkl_ast_type_is_complete (PKL_AST_TYPE_A_ETYPE (type));
            else
              complete = PKL_AST_TYPE_COMPLETE_NO;
          }
        else
          complete = PKL_AST_TYPE_COMPLETE_NO;
      }
    default:
      break;
    }

  assert (complete != PKL_AST_TYPE_COMPLETE_UNKNOWN);
  return complete;
}


/* Append the textual description of TYPE to BUFFER.  If TYPE is a
   named type then its given name is preferred if USE_GIVEN_NAME is
   1.  */
static void
pkl_type_append_to (pkl_ast_node type, int use_given_name,
                    struct string_buffer *buffer)
{
  assert (PKL_AST_CODE (type) == PKL_AST_TYPE);

  /* Use the type's given name, if requested and this specific type
     instance is named.  */
  if (use_given_name
      && PKL_AST_TYPE_NAME (type))
    {
      char *name = PKL_AST_IDENTIFIER_POINTER (PKL_AST_TYPE_NAME (type));
      char *dollar = strchr (name, '$');

      if (dollar)
        {
          sb_append_c (buffer, "a previous declaration of ");
          *dollar = '\0';
          sb_append_c (buffer, name);
          *dollar = '$';
        }
      else
        sb_append_c (buffer, name);
      return;
    }

  /* Otherwise, print a description of the type, as terse as possible
     but complete.  The descriptions should follow the same
     style/syntax/conventions used in both the language specification
     and the PVM.  */
  switch (PKL_AST_TYPE_CODE (type))
    {
    case PKL_TYPE_ANY:
      sb_append_c (buffer, "any");
      break;
    case PKL_TYPE_INTEGRAL:
      if (!PKL_AST_TYPE_I_SIGNED_P (type))
        sb_append_c (buffer, "u");
      sb_appendf (buffer, "int<%zd>", PKL_AST_TYPE_I_SIZE (type));
      break;
    case PKL_TYPE_VOID:
      sb_append_c (buffer, "void");
      break;
    case PKL_TYPE_STRING:
      sb_append_c (buffer, "string");
      break;
    case PKL_TYPE_ARRAY:
      {
        pkl_ast_node bound = PKL_AST_TYPE_A_BOUND (type);

        pkl_type_append_to (PKL_AST_TYPE_A_ETYPE (type), 1,
                            buffer);
        sb_append_c (buffer, "[");
        if (bound != NULL)
          {
            pkl_ast_node bound_type = PKL_AST_TYPE (bound);

            if (bound_type
                && PKL_AST_TYPE_CODE (bound_type) == PKL_TYPE_INTEGRAL
                && PKL_AST_CODE (bound) == PKL_AST_INTEGER)
              {
                sb_appendf (buffer, "%" PRIu64, PKL_AST_INTEGER_VALUE (bound));
              }
          }
        sb_append_c (buffer, "]");
        break;
      }
    case PKL_TYPE_STRUCT:
      {
        pkl_ast_node t;

        if (PKL_AST_TYPE_S_UNION_P (type))
          sb_append_c (buffer, "union {");
        else
          {
            if (PKL_AST_TYPE_S_ITYPE (type))
              {
                sb_append_c (buffer, "struct ");
                pkl_type_append_to (PKL_AST_TYPE_S_ITYPE (type), 0, buffer);
                sb_append_c (buffer, " {");
              }
            else
              sb_append_c (buffer, "struct {");
          }

        for (t = PKL_AST_TYPE_S_ELEMS (type); t;
             t = PKL_AST_CHAIN (t))
          {
            if (PKL_AST_CODE (t) == PKL_AST_STRUCT_TYPE_FIELD)
              {
                pkl_ast_node ename = PKL_AST_STRUCT_TYPE_FIELD_NAME (t);
                pkl_ast_node etype = PKL_AST_STRUCT_TYPE_FIELD_TYPE (t);

                if (PKL_AST_STRUCT_TYPE_FIELD_COMPUTED_P (t))
                  sb_append_c (buffer, "computed ");

                pkl_type_append_to (etype, 1, buffer);
                if (ename)
                  {
                    sb_append_c (buffer, " ");
                    sb_append_c (buffer, PKL_AST_IDENTIFIER_POINTER (ename));
                  }
                sb_append_c (buffer, ";");
              }
          }
        sb_append_c (buffer, "}");
        break;
      }
    case PKL_TYPE_FUNCTION:
      {
        pkl_ast_node t;

        sb_append_c (buffer, "(");
        for (t = PKL_AST_TYPE_F_ARGS (type); t;
             t = PKL_AST_CHAIN (t))
          {
            pkl_ast_node atype
              = PKL_AST_FUNC_TYPE_ARG_TYPE (t);

            if (t != PKL_AST_TYPE_F_ARGS (type))
              sb_append_c (buffer, ",");

            if (PKL_AST_FUNC_TYPE_ARG_VARARG (t))
              sb_append_c (buffer, "...");
            else
              {
                pkl_type_append_to (atype, 1, buffer);
                if (PKL_AST_FUNC_TYPE_ARG_OPTIONAL (t))
                  sb_append_c (buffer, "?");
              }
          }
        sb_append_c (buffer, ")");

        pkl_type_append_to (PKL_AST_TYPE_F_RTYPE (type), 1,
                            buffer);
        break;
      }
    case PKL_TYPE_OFFSET:
      {
        pkl_ast_node unit = PKL_AST_TYPE_O_UNIT (type);

        sb_append_c (buffer, "offset<");
        pkl_type_append_to (PKL_AST_TYPE_O_BASE_TYPE (type), 1,
                            buffer);
        sb_append_c (buffer, ",");

        if (PKL_AST_CODE (unit) == PKL_AST_TYPE)
          pkl_type_append_to (unit, 1, buffer);
        else if (PKL_AST_CODE (unit) == PKL_AST_IDENTIFIER)
          sb_append_c (buffer, PKL_AST_IDENTIFIER_POINTER (unit));
        else if (PKL_AST_CODE (unit) == PKL_AST_INTEGER)
          sb_appendf (buffer, "%" PRIu64, PKL_AST_INTEGER_VALUE (unit));
        else
          PK_UNREACHABLE ();

        if (PKL_AST_TYPE_O_REF_TYPE (type))
          {
            sb_append_c (buffer, ",");
            pkl_type_append_to (PKL_AST_TYPE_O_REF_TYPE (type), 1,
                                buffer);
          }

        sb_append_c (buffer, ">");
        break;
      }
    case PKL_TYPE_NOTYPE:
    default:
      PK_UNREACHABLE ();
      break;
    }
}

/* Return a string with a textual description of TYPE.  If TYPE is a
   named type then its given name is preferred if USE_GIVEN_NAME is
   1.  It is up to the caller to free the string memory.  */

char *
pkl_type_str (pkl_ast_node type, int use_given_name)
{
  struct string_buffer buffer;
  char *str;

  sb_init (&buffer);
  pkl_type_append_to (type, use_given_name, &buffer);
  str = sb_dupfree_c (&buffer);
  if (str == NULL)
    /* The only possible error here is out-of-memory.  */
    xalloc_die ();
  return str;
}

/* Print a textual description of TYPE to the file OUT.  If TYPE is a
   named type then its given name is preferred if USE_GIVEN_NAME is
   1.  */

void
pkl_print_type (FILE *out, pkl_ast_node type, int use_given_name)
{
  char *str = pkl_type_str (type, use_given_name);
  fputs (str, out);
  free (str);
}

/* Return a boolean telling whether the given type function only have
   optional arguments, i.e. all arguments have an initializer.  */

int
pkl_ast_func_all_optargs (pkl_ast_node type)
{
  pkl_ast_node arg;
  int all_optargs = 1;

  for (arg = PKL_AST_TYPE_F_ARGS (type); arg; arg = PKL_AST_CHAIN (arg))
    {
      if (!PKL_AST_FUNC_TYPE_ARG_OPTIONAL (arg))
        {
          all_optargs = 0;
          break;
        }
    }

  return all_optargs;
}

/* Build and return an AST node for an enum.  */

pkl_ast_node
pkl_ast_make_enum (pkl_ast ast,
                   pkl_ast_node tag, pkl_ast_node values)
{
  pkl_ast_node enumeration
    = pkl_ast_make_node (ast, PKL_AST_ENUM);

  assert (tag && values);

  PKL_AST_ENUM_TAG (enumeration) = ASTREF (tag);
  PKL_AST_ENUM_VALUES (enumeration) = ASTREF (values);

  return enumeration;
}

/* Build and return an AST node for an array.  */

pkl_ast_node
pkl_ast_make_array (pkl_ast ast,
                    size_t nelem, size_t ninitializer,
                    pkl_ast_node initializers)
{
  pkl_ast_node array
    = pkl_ast_make_node (ast, PKL_AST_ARRAY);

  PKL_AST_ARRAY_NELEM (array) = nelem;
  PKL_AST_ARRAY_NINITIALIZER (array) = ninitializer;
  PKL_AST_ARRAY_INITIALIZERS (array) = ASTREF (initializers);

  return array;
}

/* Concatenates two chain of array initializers and fixes the indices of
   second initializer accordingly.  */

pkl_ast_node
pkl_ast_array_initializers_concat (pkl_ast ast,
                                   pkl_ast_node init1,
                                   pkl_ast_node init2)
{
  pkl_ast_node init, cursor, tmp;
  pkl_ast_node index, exp;
  size_t idx;

  assert (init1);
  assert (init2);

  index = PKL_AST_ARRAY_INITIALIZER_INDEX (init1);
  exp = PKL_AST_ARRAY_INITIALIZER_EXP (init1);
  init = pkl_ast_make_array_initializer (ast, index, exp);
  idx = 1;
  cursor = init;
  for (tmp = PKL_AST_CHAIN (init1); tmp; tmp = PKL_AST_CHAIN (tmp), idx++)
    {
      index = PKL_AST_ARRAY_INITIALIZER_INDEX (tmp);
      exp = PKL_AST_ARRAY_INITIALIZER_EXP (tmp);
      PKL_AST_CHAIN (cursor)
          = ASTREF (pkl_ast_make_array_initializer (ast, index, exp));
      cursor = PKL_AST_CHAIN (cursor);
    }
  for (tmp = init2; tmp; tmp = PKL_AST_CHAIN (tmp), idx++)
    {
      pkl_ast_node index_type
          = PKL_AST_TYPE (PKL_AST_ARRAY_INITIALIZER_INDEX (tmp));

      index = pkl_ast_make_integer (ast, idx);
      PKL_AST_TYPE (index) = ASTREF (index_type);
      exp = PKL_AST_ARRAY_INITIALIZER_EXP (tmp);
      PKL_AST_CHAIN (cursor)
          = ASTREF (pkl_ast_make_array_initializer (ast, index, exp));
      cursor = PKL_AST_CHAIN (cursor);
    }

  return init;
}

/* Build and return an AST node for an array element.  */

pkl_ast_node
pkl_ast_make_array_initializer (pkl_ast ast,
                                pkl_ast_node index, pkl_ast_node exp)
{
  pkl_ast_node initializer
    = pkl_ast_make_node (ast, PKL_AST_ARRAY_INITIALIZER);

  PKL_AST_ARRAY_INITIALIZER_INDEX (initializer) = ASTREF (index);
  PKL_AST_ARRAY_INITIALIZER_EXP (initializer) = ASTREF (exp);

  return initializer;
}

/* Build and return an AST node for a struct.  */

pkl_ast_node
pkl_ast_make_struct (pkl_ast ast,
                     size_t nelem,
                     pkl_ast_node elems)
{
  pkl_ast_node sct = pkl_ast_make_node (ast, PKL_AST_STRUCT);

  PKL_AST_STRUCT_NELEM (sct) = nelem;
  PKL_AST_STRUCT_FIELDS (sct) = ASTREF (elems);

  return sct;
}

/* Build and return an AST node for a struct field.  */

pkl_ast_node
pkl_ast_make_struct_field (pkl_ast ast,
                           pkl_ast_node name,
                           pkl_ast_node exp)
{
  pkl_ast_node elem = pkl_ast_make_node (ast, PKL_AST_STRUCT_FIELD);

  if (name != NULL)
    PKL_AST_STRUCT_FIELD_NAME (elem) = ASTREF (name);
  PKL_AST_STRUCT_FIELD_EXP (elem) = ASTREF (exp);

  return elem;
}

/* Build and return an AST node for a declaration.  */

pkl_ast_node
pkl_ast_make_decl (pkl_ast ast, int kind, pkl_ast_node name,
                   pkl_ast_node initial, const char *source)
{
  pkl_ast_node decl = pkl_ast_make_node (ast, PKL_AST_DECL);

  assert (name);

  PKL_AST_DECL_KIND (decl) = kind;
  PKL_AST_DECL_NAME (decl) = ASTREF (name);
  PKL_AST_DECL_INITIAL (decl) = ASTREF (initial);
  PKL_AST_DECL_IMMUTABLE_P (decl) = 0;
  if (source)
    PKL_AST_DECL_SOURCE (decl) = xstrdup (source);

  return decl;
}

/* Link the given PKL_AST_TYPE alias node to DECL.  */

void
pkl_ast_add_type_name_to_decl (pkl_ast_node decl,
                               pkl_ast_node type_name)
{
  assert (PKL_AST_CODE (type_name) == PKL_AST_TYPE);
  assert (PKL_AST_TYPE_CODE2 (type_name) == PKL_TYPE_ALIAS);

  PKL_AST_TYPE_L_NEXT_IN_DECL (type_name) = PKL_AST_DECL_TYPE_NAMES (decl);
  PKL_AST_DECL_TYPE_NAMES (decl) = ASTREF (type_name);
}

/* Given a declaration DECL and a NEW_NAME, rename the declaration to
   the new name.  If the declaration is of a type, then also rename
   all the type names linked in it.  */

void
pkl_ast_rename_decl (pkl_ast ast, pkl_ast_node decl, const char *new_name)
{
  pkl_ast_node name = PKL_AST_DECL_NAME (decl);

  /* First replace the identifier in the declaration with the new
     name.  */
  pkl_ast_node_free (name);
  name = pkl_ast_make_identifier (ast, new_name);
  PKL_AST_DECL_NAME (decl) = ASTREF (name);

  /* Then rename linked aliases if the declaration is of a type.  */
  if (PKL_AST_DECL_KIND (decl) == PKL_AST_DECL_KIND_TYPE)
    {
      pkl_ast_node type_name = PKL_AST_DECL_TYPE_NAMES (decl);

      while (type_name != NULL)
        {
          pkl_ast_node next = PKL_AST_TYPE_L_NEXT_IN_DECL (type_name);

          pkl_ast_node_free (PKL_AST_TYPE_L_NAME (type_name));
          PKL_AST_TYPE_L_NAME (type_name) = ASTREF (name);
          type_name = next;
        }
    }
}

/* Build and return an AST node for an offset construct.  */

pkl_ast_node
pkl_ast_make_offset (pkl_ast ast,
                     pkl_ast_node magnitude, pkl_ast_node unit)
{
  pkl_ast_node offset = pkl_ast_make_node (ast, PKL_AST_OFFSET);

  assert (unit);

  if (magnitude != NULL)
    PKL_AST_OFFSET_MAGNITUDE (offset) = ASTREF (magnitude);
  PKL_AST_OFFSET_UNIT (offset) = ASTREF (unit);
  PKL_AST_LITERAL_P (offset)
    = magnitude ? PKL_AST_LITERAL_P (PKL_AST_OFFSET_MAGNITUDE (offset))
                    && PKL_AST_LITERAL_P (PKL_AST_OFFSET_UNIT (offset))
                : 0;

  return offset;
}

/* Build and return an AST node for a cast.  */

pkl_ast_node
pkl_ast_make_cast (pkl_ast ast,
                   pkl_ast_node type, pkl_ast_node exp)
{
  pkl_ast_node cast = pkl_ast_make_node (ast, PKL_AST_CAST);

  assert (type && exp);

  PKL_AST_CAST_TYPE (cast) = ASTREF (type);
  PKL_AST_CAST_EXP (cast) = ASTREF (exp);

  return cast;
}

/* Build and return an AST node for an `isa' operation.  */

pkl_ast_node
pkl_ast_make_isa (pkl_ast ast,
                  pkl_ast_node type, pkl_ast_node exp)
{
  pkl_ast_node isa = pkl_ast_make_node (ast, PKL_AST_ISA);

  assert (type && exp);

  PKL_AST_ISA_TYPE (isa) = ASTREF (type);
  PKL_AST_ISA_EXP (isa) = ASTREF (exp);

  return isa;
}

/* Build and return an AST node for a map.  */

pkl_ast_node
pkl_ast_make_map (pkl_ast ast,
                  int strict_p,
                  pkl_ast_node type,
                  pkl_ast_node ios,
                  pkl_ast_node offset)
{
  pkl_ast_node map = pkl_ast_make_node (ast, PKL_AST_MAP);

  assert (type && offset);

  PKL_AST_MAP_STRICT_P (map) = strict_p;
  PKL_AST_MAP_TYPE (map) = ASTREF (type);
  PKL_AST_MAP_IOS (map) = ASTREF (ios);
  PKL_AST_MAP_OFFSET (map) = ASTREF (offset);

  return map;
}

/* Build and return an AST node for a value constructor.  */

pkl_ast_node
pkl_ast_make_cons (pkl_ast ast,
                   pkl_ast_node type, pkl_ast_node value)
{
  pkl_ast_node cons = pkl_ast_make_node (ast, PKL_AST_CONS);

  assert (type);

  PKL_AST_CONS_KIND (cons) = PKL_AST_CONS_KIND_UNKNOWN;
  PKL_AST_CONS_TYPE (cons) = ASTREF (type);
  PKL_AST_CONS_VALUE (cons) = ASTREF (value);
  return cons;
}

/* Build and return an AST node for a function call.  */

pkl_ast_node
pkl_ast_make_funcall (pkl_ast ast,
                      pkl_ast_node function, pkl_ast_node args)
{
  pkl_ast_node funcall = pkl_ast_make_node (ast,
                                            PKL_AST_FUNCALL);

  assert (function);

  PKL_AST_FUNCALL_FUNCTION (funcall) = ASTREF (function);
  if (args)
    PKL_AST_FUNCALL_ARGS (funcall) = ASTREF (args);
  return funcall;
}

/* Build and return an AST node for an actual argument of a function
   call.  */

pkl_ast_node
pkl_ast_make_funcall_arg (pkl_ast ast, pkl_ast_node exp,
                          pkl_ast_node name)
{
  pkl_ast_node funcall_arg = pkl_ast_make_node (ast,
                                                PKL_AST_FUNCALL_ARG);

  if (exp)
    PKL_AST_FUNCALL_ARG_EXP (funcall_arg) = ASTREF (exp);
  if (name)
    PKL_AST_FUNCALL_ARG_NAME (funcall_arg) = ASTREF (name);
  PKL_AST_FUNCALL_ARG_FIRST_VARARG (funcall_arg) = 0;
  return funcall_arg;
}

/* Build and return an AST node for `format'.  */

pkl_ast_node
pkl_ast_make_format (pkl_ast ast,
                     pkl_ast_node fmt, pkl_ast_node args, int printf_p)
{
  pkl_ast_node format = pkl_ast_make_node (ast, PKL_AST_FORMAT);

  PKL_AST_FORMAT_FMT (format) = ASTREF (fmt);
  if (args)
    PKL_AST_FORMAT_ARGS (format) = ASTREF (args);

  return format;
}

/* Build and return an AST node for a `format' argument.  */

pkl_ast_node
pkl_ast_make_format_arg (pkl_ast ast, pkl_ast_node exp)
{
  pkl_ast_node format_arg = pkl_ast_make_node (ast, PKL_AST_FORMAT_ARG);

  if (exp)
    PKL_AST_FORMAT_ARG_EXP (format_arg) = ASTREF (exp);
  return format_arg;
}

/* Build and return an AST node for a variable reference.  */

pkl_ast_node
pkl_ast_make_var (pkl_ast ast, pkl_ast_node name,
                  pkl_ast_node decl, int back, int over)
{
  pkl_ast_node var = pkl_ast_make_node (ast, PKL_AST_VAR);

  assert (name && decl);

  PKL_AST_VAR_NAME (var) = ASTREF (name);
  PKL_AST_VAR_DECL (var) = ASTREF (decl);
  PKL_AST_VAR_BACK (var) = back;
  PKL_AST_VAR_OVER (var) = over;

  return var;
}

/* Build and return an AST node for an incrdecr expression.  */

pkl_ast_node
pkl_ast_make_incrdecr (pkl_ast ast,
                       pkl_ast_node exp, int order, int sign, int float_p)
{
  pkl_ast_node incrdecr = pkl_ast_make_node (ast,
                                             PKL_AST_INCRDECR);

  assert (order == PKL_AST_ORDER_PRE || order == PKL_AST_ORDER_POST);
  assert (sign == PKL_AST_SIGN_INCR || sign == PKL_AST_SIGN_DECR);
  assert (exp);

  PKL_AST_INCRDECR_EXP (incrdecr) = ASTREF (exp);
  PKL_AST_INCRDECR_ORDER (incrdecr) = order;
  PKL_AST_INCRDECR_SIGN (incrdecr) = sign;
  PKL_AST_INCRDECR_FLOAT_P (incrdecr) = !!float_p;

  return incrdecr;
}

/* Build and return an AST node for a lambda expression.  */

pkl_ast_node
pkl_ast_make_lambda (pkl_ast ast, pkl_ast_node function)
{
  pkl_ast_node lambda = pkl_ast_make_node (ast, PKL_AST_LAMBDA);

  assert (function);

  PKL_AST_LAMBDA_FUNCTION (lambda) = ASTREF (function);
  return lambda;
}

/* Build and return an AST node for an `asm' expression.  */
pkl_ast_node
pkl_ast_make_asm_exp (pkl_ast ast, pkl_ast_node type,
                      pkl_ast_node template, pkl_ast_node inputs)
{
  pkl_ast_node asm_exp = pkl_ast_make_node (ast, PKL_AST_ASM_EXP);

  assert (type);
  assert (template);

  PKL_AST_ASM_EXP_TEMPLATE (asm_exp) = ASTREF (template);
  PKL_AST_ASM_EXP_TYPE (asm_exp) = ASTREF (type);
  if (inputs)
    PKL_AST_ASM_EXP_INPUTS (asm_exp) = ASTREF (inputs);

  return asm_exp;
}

/* Build and return an AST node for a compound statement.  */

pkl_ast_node
pkl_ast_make_comp_stmt (pkl_ast ast, pkl_ast_node stmts)
{
  pkl_ast_node comp_stmt = pkl_ast_make_node (ast,
                                              PKL_AST_COMP_STMT);

  if (stmts)
    PKL_AST_COMP_STMT_STMTS (comp_stmt) = ASTREF (stmts);
  return comp_stmt;
}

/* Build and return an AST node for an assignment statement.  */

pkl_ast_node
pkl_ast_make_ass_stmt (pkl_ast ast, pkl_ast_node lvalue,
                       pkl_ast_node exp)
{
  pkl_ast_node ass_stmt = pkl_ast_make_node (ast,
                                             PKL_AST_ASS_STMT);

  assert (lvalue);

  PKL_AST_ASS_STMT_LVALUE (ass_stmt) = ASTREF (lvalue);
  if (exp)
    PKL_AST_ASS_STMT_EXP (ass_stmt) = ASTREF (exp);

  return ass_stmt;
}

/* Build and return an AST node for a conditional statement.  */

pkl_ast_node
pkl_ast_make_if_stmt (pkl_ast ast, pkl_ast_node exp,
                      pkl_ast_node then_stmt, pkl_ast_node else_stmt)
{
  pkl_ast_node if_stmt = pkl_ast_make_node (ast, PKL_AST_IF_STMT);

  assert (exp && then_stmt);

  PKL_AST_IF_STMT_EXP (if_stmt) = ASTREF (exp);
  PKL_AST_IF_STMT_THEN_STMT (if_stmt) = ASTREF (then_stmt);
  if (else_stmt)
    PKL_AST_IF_STMT_ELSE_STMT (if_stmt) = ASTREF (else_stmt);

  return if_stmt;
}

/* Build and return an AST node for a loop statement.  */

pkl_ast_node
pkl_ast_make_loop_stmt (pkl_ast ast,
                        int kind,
                        pkl_ast_node iterator,
                        pkl_ast_node condition,
                        pkl_ast_node head, pkl_ast_node tail,
                        pkl_ast_node body)
{
  pkl_ast_node loop_stmt
    = pkl_ast_make_node (ast, PKL_AST_LOOP_STMT);

  assert (body);
  assert (kind == PKL_AST_LOOP_STMT_KIND_WHILE
          || kind == PKL_AST_LOOP_STMT_KIND_FOR
          || kind == PKL_AST_LOOP_STMT_KIND_FOR_IN);

  PKL_AST_LOOP_STMT_KIND (loop_stmt) = kind;
  if (iterator)
    PKL_AST_LOOP_STMT_ITERATOR (loop_stmt)
      = ASTREF (iterator);
  if (condition)
    PKL_AST_LOOP_STMT_CONDITION (loop_stmt)
      = ASTREF (condition);
  if (head)
    PKL_AST_LOOP_STMT_HEAD (loop_stmt) = ASTREF (head);
  if (tail)
    PKL_AST_LOOP_STMT_TAIL (loop_stmt) = ASTREF (tail);
  PKL_AST_LOOP_STMT_BODY (loop_stmt) = ASTREF (body);

  return loop_stmt;
}

/* Build and return an AST node for the iterator of a loop
   statement.  */

pkl_ast_node
pkl_ast_make_loop_stmt_iterator (pkl_ast ast, pkl_ast_node decl,
                                 pkl_ast_node container)
{
  pkl_ast_node loop_stmt_iterator
    = pkl_ast_make_node (ast, PKL_AST_LOOP_STMT_ITERATOR);

  assert (decl && container);

  PKL_AST_LOOP_STMT_ITERATOR_DECL (loop_stmt_iterator)
    = ASTREF (decl);
  PKL_AST_LOOP_STMT_ITERATOR_CONTAINER (loop_stmt_iterator)
    = ASTREF (container);

  return loop_stmt_iterator;
}

/* Build and return an AST node for a return statement.  */

pkl_ast_node
pkl_ast_make_return_stmt (pkl_ast ast, pkl_ast_node exp)
{
  pkl_ast_node return_stmt = pkl_ast_make_node (ast,
                                                PKL_AST_RETURN_STMT);

  PKL_AST_RETURN_STMT_EXP (return_stmt) = ASTREF (exp);
  return return_stmt;
}

/* Build and return an AST node for a "null statement".  */

pkl_ast_node
pkl_ast_make_null_stmt (pkl_ast ast)
{
  pkl_ast_node null_stmt = pkl_ast_make_node (ast,
                                              PKL_AST_NULL_STMT);
  return null_stmt;
}

/* Build and return an AST node for an "expression statement".  */

pkl_ast_node
pkl_ast_make_exp_stmt (pkl_ast ast, pkl_ast_node exp)
{
  pkl_ast_node exp_stmt = pkl_ast_make_node (ast,
                                             PKL_AST_EXP_STMT);

  assert (exp);

  PKL_AST_EXP_STMT_EXP (exp_stmt) = ASTREF (exp);
  return exp_stmt;
}

/* Build and return an AST node for a `try' statement.  */

pkl_ast_node
pkl_ast_make_try_stmt (pkl_ast ast,
                       int kind,
                       pkl_ast_node body, pkl_ast_node handler,
                       pkl_ast_node arg, pkl_ast_node exp)
{
  pkl_ast_node try_stmt = pkl_ast_make_node (ast,
                                             PKL_AST_TRY_STMT);

  assert (body);

  PKL_AST_TRY_STMT_KIND (try_stmt) = kind;
  PKL_AST_TRY_STMT_BODY (try_stmt) = ASTREF (body);
  if (handler)
    PKL_AST_TRY_STMT_HANDLER (try_stmt) = ASTREF (handler);
  if (arg)
    PKL_AST_TRY_STMT_ARG (try_stmt) = ASTREF (arg);
  if (exp)
    PKL_AST_TRY_STMT_EXP (try_stmt) = ASTREF (exp);

  return try_stmt;
}

/* Build and return an AST node for the body of a `try' statement.  */

pkl_ast_node
pkl_ast_make_try_stmt_body (pkl_ast ast, pkl_ast_node code)
{
  pkl_ast_node try_stmt_body = pkl_ast_make_node (ast,
                                                  PKL_AST_TRY_STMT_BODY);

  assert (code);

  PKL_AST_TRY_STMT_BODY_CODE (try_stmt_body) = ASTREF (code);
  return try_stmt_body;
}

/* Build and return an AST node for handler of a `try-catch' statement.  */

pkl_ast_node
pkl_ast_make_try_stmt_handler (pkl_ast ast, pkl_ast_node code)
{
  pkl_ast_node try_stmt_handler
    = pkl_ast_make_node (ast, PKL_AST_TRY_STMT_HANDLER);

  assert (code);

  PKL_AST_TRY_STMT_HANDLER_CODE (try_stmt_handler) = ASTREF (code);
  return try_stmt_handler;
}

/* Build and return an AST node for a `print' statement.  */

pkl_ast_node
pkl_ast_make_print_stmt (pkl_ast ast,
                         int printf_p, pkl_ast_node fmt)
{
  pkl_ast_node print_stmt = pkl_ast_make_node (ast, PKL_AST_PRINT_STMT);

  assert (fmt != NULL);

  if (printf_p) /* printf statement */
    PKL_AST_PRINT_STMT_FORMAT (print_stmt) = ASTREF (fmt);
  else /* print statement */
    PKL_AST_PRINT_STMT_STR_EXP (print_stmt) = ASTREF (fmt);

  return print_stmt;
}

/* Build and return an AST node for a `continue' statement.  */

pkl_ast_node
pkl_ast_make_break_continue_stmt (pkl_ast ast, int kind)
{
  pkl_ast_node break_continue_stmt
    = pkl_ast_make_node (ast, PKL_AST_BREAK_CONTINUE_STMT);

  PKL_AST_BREAK_CONTINUE_STMT_KIND (break_continue_stmt) = kind;
  return break_continue_stmt;
}

/* Build and return an AST node for a `raise' statement.  */

pkl_ast_node
pkl_ast_make_raise_stmt (pkl_ast ast, pkl_ast_node exp)
{
  pkl_ast_node raise_stmt = pkl_ast_make_node (ast,
                                               PKL_AST_RAISE_STMT);

  if (exp)
    PKL_AST_RAISE_STMT_EXP (raise_stmt) = ASTREF (exp);
  return raise_stmt;
}

/* Build and return an AST node for an `asm' statement.  */

pkl_ast_node
pkl_ast_make_asm_stmt (pkl_ast ast, pkl_ast_node template,
                       pkl_ast_node inputs, pkl_ast_node outputs)
{
  pkl_ast_node asm_stmt = pkl_ast_make_node (ast,
                                             PKL_AST_ASM_STMT);

  assert (template);
  PKL_AST_ASM_STMT_TEMPLATE (asm_stmt) = ASTREF (template);
  if (inputs)
    PKL_AST_ASM_STMT_INPUTS (asm_stmt) = ASTREF (inputs);
  if (outputs)
    PKL_AST_ASM_STMT_OUTPUTS (asm_stmt) = ASTREF (outputs);
  return asm_stmt;
}

/* Build and return an AST node for a PKL program.  */

pkl_ast_node
pkl_ast_make_program (pkl_ast ast, pkl_ast_node elems)
{
  pkl_ast_node program
    = pkl_ast_make_node (ast, PKL_AST_PROGRAM);

  PKL_AST_PROGRAM_ELEMS (program) = ASTREF (elems);
  return program;
}

/* Build and return an AST node for a source file change.  */

pkl_ast_node
pkl_ast_make_src (pkl_ast ast, const char *filename)
{
  pkl_ast_node src = pkl_ast_make_node (ast, PKL_AST_SRC);

  PKL_AST_SRC_FILENAME (src) = filename ? xstrdup (filename) : NULL;
  return src;
}

/* Free the AST nodes linked by PKL_AST_CHAIN.  */
void
pkl_ast_node_free_chain (pkl_ast_node ast)
{
  pkl_ast_node n, next;

  for (n = ast; n; n = next)
    {
      next = PKL_AST_CHAIN (n);
      pkl_ast_node_free (n);
    }
}

/* Recursively descends down a tree, marking and freeing as it goes.
   VISITATIONS is a set of pointers that has already been freed that this
   function can track frees in.  */

static void
pkl_ast_node_free_1 (gl_set_t visitations, pkl_ast_node ast)
{
#define PKL_AST_NODE_FREE(...) \
  pkl_ast_node_free_1 (visitations, __VA_ARGS__)

  /* Take care not to use pkl_ast_node_free here, as doing that will result in
     a double-free, as it throws away the current visitation set.  In the same
     vein, take care to mark and check VISITATIONS, using VISIT_AND_FREE when
     possible.  */
  pkl_ast_node t, n;
  size_t i;
  bool added;

  if (ast == NULL)
    return;

  /* Check if we already freed this one.  */
  if (gl_set_search (visitations, ast))
    return;


#define VISIT_AND_FREE(ptr)                     \
  do {                                          \
    if (!ptr)                                   \
      break;                                    \
                                                \
    bool added = gl_set_add (visitations, ptr); \
                                                \
    /* This one was already freed.  */          \
    if (!added)                                 \
      break;                                    \
                                                \
    free (ptr);                                 \
  } while (0)


  assert (PKL_AST_REFCOUNT (ast) > 0);

  if (PKL_AST_REFCOUNT (ast) > 1)
    {
      PKL_AST_REFCOUNT (ast) -= 1;
      return;
    }

  /* OK, we need to free.  Mark this node as freed (it will be actually freed
     at the end).  */
  added = gl_set_add (visitations, ast);
  assert (added);

  switch (PKL_AST_CODE (ast))
    {
    case PKL_AST_PROGRAM:
      for (t = PKL_AST_PROGRAM_ELEMS (ast); t; t = n)
        {
          n = PKL_AST_CHAIN (t);
          PKL_AST_NODE_FREE (t);
        }
      break;

    case PKL_AST_SRC:
      VISIT_AND_FREE (PKL_AST_SRC_FILENAME (ast));
      break;

    case PKL_AST_EXP:

      for (i = 0; i < PKL_AST_EXP_NUMOPS (ast); i++)
        PKL_AST_NODE_FREE (PKL_AST_EXP_OPERAND (ast, i));

      break;

    case PKL_AST_COND_EXP:

      PKL_AST_NODE_FREE (PKL_AST_COND_EXP_COND (ast));
      PKL_AST_NODE_FREE (PKL_AST_COND_EXP_THENEXP (ast));
      PKL_AST_NODE_FREE (PKL_AST_COND_EXP_ELSEEXP (ast));
      break;

    case PKL_AST_ENUM:

      PKL_AST_NODE_FREE (PKL_AST_ENUM_TAG (ast));

      for (t = PKL_AST_ENUM_VALUES (ast); t; t = n)
        {
          n = PKL_AST_CHAIN (t);
          PKL_AST_NODE_FREE (t);
        }

      break;

    case PKL_AST_ENUMERATOR:

      PKL_AST_NODE_FREE (PKL_AST_ENUMERATOR_IDENTIFIER (ast));
      PKL_AST_NODE_FREE (PKL_AST_ENUMERATOR_VALUE (ast));
      break;

    case PKL_AST_TYPE:

      if (PKL_AST_TYPE_NAME (ast))
        {
          PKL_AST_NODE_FREE (PKL_AST_TYPE_L_NAME (ast));
          PKL_AST_NODE_FREE (PKL_AST_TYPE_L_TYPE (ast));
        }
      else
        {
          switch (PKL_AST_TYPE_CODE (ast))
            {
            case PKL_TYPE_ARRAY:
              pvm_free_uncollectable (PKL_AST_TYPE_A_CLOSURES (ast));

              PKL_AST_NODE_FREE (PKL_AST_TYPE_A_BOUND (ast));
              PKL_AST_NODE_FREE (PKL_AST_TYPE_A_ETYPE (ast));
              break;
            case PKL_TYPE_STRUCT:
              pvm_free_uncollectable (PKL_AST_TYPE_S_CLOSURES (ast));

              for (t = PKL_AST_TYPE_S_ELEMS (ast); t; t = n)
                {
                  n = PKL_AST_CHAIN (t);
                  PKL_AST_NODE_FREE (t);
                }
              break;
            case PKL_TYPE_FUNCTION:
              PKL_AST_NODE_FREE (PKL_AST_TYPE_F_RTYPE (ast));
              PKL_AST_NODE_FREE (PKL_AST_TYPE_F_FIRST_OPT_ARG (ast));
              for (t = PKL_AST_TYPE_F_ARGS (ast); t; t = n)
                {
                  n = PKL_AST_CHAIN (t);
                  PKL_AST_NODE_FREE (t);
                }
              break;
            case PKL_TYPE_OFFSET:
              PKL_AST_NODE_FREE (PKL_AST_TYPE_O_UNIT (ast));
              PKL_AST_NODE_FREE (PKL_AST_TYPE_O_BASE_TYPE (ast));
              PKL_AST_NODE_FREE (PKL_AST_TYPE_O_REF_TYPE (ast));
              break;
            case PKL_TYPE_INTEGRAL:
            case PKL_TYPE_STRING:
            default:
              break;
            }
        }
      break;

    case PKL_AST_STRUCT_TYPE_FIELD:

      PKL_AST_NODE_FREE (PKL_AST_STRUCT_TYPE_FIELD_NAME (ast));
      PKL_AST_NODE_FREE (PKL_AST_STRUCT_TYPE_FIELD_TYPE (ast));
      PKL_AST_NODE_FREE (PKL_AST_STRUCT_TYPE_FIELD_SIZE (ast));
      PKL_AST_NODE_FREE (PKL_AST_STRUCT_TYPE_FIELD_CONSTRAINT (ast));
      free (PKL_AST_STRUCT_TYPE_FIELD_CONSTRAINT_SRC (ast));
      PKL_AST_NODE_FREE (PKL_AST_STRUCT_TYPE_FIELD_INITIALIZER (ast));
      PKL_AST_NODE_FREE (PKL_AST_STRUCT_TYPE_FIELD_LABEL (ast));
      PKL_AST_NODE_FREE (PKL_AST_STRUCT_TYPE_FIELD_OPTCOND_PRE (ast));
      PKL_AST_NODE_FREE (PKL_AST_STRUCT_TYPE_FIELD_OPTCOND_POST (ast));
      break;

    case PKL_AST_FUNC_TYPE_ARG:

      PKL_AST_NODE_FREE (PKL_AST_FUNC_TYPE_ARG_TYPE (ast));
      PKL_AST_NODE_FREE (PKL_AST_FUNC_TYPE_ARG_NAME (ast));
      break;

    case PKL_AST_INDEXER:

      PKL_AST_NODE_FREE (PKL_AST_INDEXER_ENTITY (ast));
      PKL_AST_NODE_FREE (PKL_AST_INDEXER_INDEX (ast));
      break;

    case PKL_AST_TRIMMER:

      PKL_AST_NODE_FREE (PKL_AST_TRIMMER_ENTITY (ast));
      PKL_AST_NODE_FREE (PKL_AST_TRIMMER_FROM (ast));
      PKL_AST_NODE_FREE (PKL_AST_TRIMMER_TO (ast));
      PKL_AST_NODE_FREE (PKL_AST_TRIMMER_ADDEND (ast));
      break;

    case PKL_AST_FUNC:

      VISIT_AND_FREE (PKL_AST_FUNC_NAME (ast));
      PKL_AST_NODE_FREE (PKL_AST_FUNC_RET_TYPE (ast));
      PKL_AST_NODE_FREE (PKL_AST_FUNC_BODY (ast));
      PKL_AST_NODE_FREE (PKL_AST_FUNC_FIRST_OPT_ARG (ast));
      for (t = PKL_AST_FUNC_ARGS (ast); t; t = n)
            {
              n = PKL_AST_CHAIN (t);
              PKL_AST_NODE_FREE (t);
            }
      break;

    case PKL_AST_FUNC_ARG:

      PKL_AST_NODE_FREE (PKL_AST_FUNC_ARG_TYPE (ast));
      PKL_AST_NODE_FREE (PKL_AST_FUNC_ARG_IDENTIFIER (ast));
      PKL_AST_NODE_FREE (PKL_AST_FUNC_ARG_INITIAL (ast));
      break;

    case PKL_AST_STRING:

      VISIT_AND_FREE (PKL_AST_STRING_POINTER (ast));
      break;

    case PKL_AST_IDENTIFIER:

      VISIT_AND_FREE (PKL_AST_IDENTIFIER_POINTER (ast));
      break;

    case PKL_AST_STRUCT_REF:

      PKL_AST_NODE_FREE (PKL_AST_STRUCT_REF_STRUCT (ast));
      PKL_AST_NODE_FREE (PKL_AST_STRUCT_REF_IDENTIFIER (ast));
      PKL_AST_NODE_FREE (PKL_AST_STRUCT_REF_ORIG_TYPE (ast));
      break;

    case PKL_AST_STRUCT_FIELD:

      PKL_AST_NODE_FREE (PKL_AST_STRUCT_FIELD_NAME (ast));
      PKL_AST_NODE_FREE (PKL_AST_STRUCT_FIELD_EXP (ast));
      break;

    case PKL_AST_STRUCT:

      for (t = PKL_AST_STRUCT_FIELDS (ast); t; t = n)
        {
          n = PKL_AST_CHAIN (t);
          PKL_AST_NODE_FREE (t);
        }
      break;

    case PKL_AST_ARRAY_INITIALIZER:

      PKL_AST_NODE_FREE (PKL_AST_ARRAY_INITIALIZER_INDEX (ast));
      PKL_AST_NODE_FREE (PKL_AST_ARRAY_INITIALIZER_EXP (ast));
      break;

    case PKL_AST_ARRAY:

      for (t = PKL_AST_ARRAY_INITIALIZERS (ast); t; t = n)
        {
          n = PKL_AST_CHAIN (t);
          PKL_AST_NODE_FREE (t);
        }
      if (PKL_AST_ARRAY_ELEM_CAST (ast))
        PKL_AST_NODE_FREE (PKL_AST_ARRAY_ELEM_CAST (ast));

      break;

    case PKL_AST_DECL:

      VISIT_AND_FREE (PKL_AST_DECL_SOURCE (ast));
      PKL_AST_NODE_FREE (PKL_AST_DECL_NAME (ast));
      PKL_AST_NODE_FREE (PKL_AST_DECL_INITIAL (ast));
      PKL_AST_NODE_FREE (PKL_AST_DECL_PREV_DECL (ast));
      break;

    case PKL_AST_OFFSET:

      PKL_AST_NODE_FREE (PKL_AST_OFFSET_MAGNITUDE (ast));
      PKL_AST_NODE_FREE (PKL_AST_OFFSET_UNIT (ast));
      break;

    case PKL_AST_CAST:

      PKL_AST_NODE_FREE (PKL_AST_CAST_TYPE (ast));
      PKL_AST_NODE_FREE (PKL_AST_CAST_EXP (ast));
      break;

    case PKL_AST_ISA:

      PKL_AST_NODE_FREE (PKL_AST_ISA_TYPE (ast));
      PKL_AST_NODE_FREE (PKL_AST_ISA_EXP (ast));
      break;

    case PKL_AST_MAP:

      PKL_AST_NODE_FREE (PKL_AST_MAP_TYPE (ast));
      PKL_AST_NODE_FREE (PKL_AST_MAP_IOS (ast));
      PKL_AST_NODE_FREE (PKL_AST_MAP_OFFSET (ast));
      break;

    case PKL_AST_CONS:

      PKL_AST_NODE_FREE (PKL_AST_CONS_TYPE (ast));
      PKL_AST_NODE_FREE (PKL_AST_CONS_VALUE (ast));
      break;

    case PKL_AST_FUNCALL:

      PKL_AST_NODE_FREE (PKL_AST_FUNCALL_FUNCTION (ast));
      for (t = PKL_AST_FUNCALL_ARGS (ast); t; t = n)
        {
          n = PKL_AST_CHAIN (t);
          PKL_AST_NODE_FREE (t);
        }

      break;

    case PKL_AST_FUNCALL_ARG:

      PKL_AST_NODE_FREE (PKL_AST_FUNCALL_ARG_EXP (ast));
      PKL_AST_NODE_FREE (PKL_AST_FUNCALL_ARG_NAME (ast));
      break;

    case PKL_AST_VAR:

      PKL_AST_NODE_FREE (PKL_AST_VAR_NAME (ast));
      PKL_AST_NODE_FREE (PKL_AST_VAR_DECL (ast));
      break;

    case PKL_AST_INCRDECR:

      PKL_AST_NODE_FREE (PKL_AST_INCRDECR_EXP (ast));
      break;

    case PKL_AST_LAMBDA:

      PKL_AST_NODE_FREE (PKL_AST_LAMBDA_FUNCTION (ast));
      break;

    case PKL_AST_ASM_EXP:

      PKL_AST_NODE_FREE (PKL_AST_ASM_EXP_TYPE (ast));
      PKL_AST_NODE_FREE (PKL_AST_ASM_EXP_TEMPLATE (ast));

      for (t = PKL_AST_ASM_EXP_INPUTS (ast); t; t = n)
        {
          n = PKL_AST_CHAIN (t);
          PKL_AST_NODE_FREE (t);
        }

      break;

    case PKL_AST_COMP_STMT:

      for (t = PKL_AST_COMP_STMT_STMTS (ast); t; t = n)
        {
          n = PKL_AST_CHAIN (t);
          PKL_AST_NODE_FREE (t);
        }

      break;

    case PKL_AST_ASS_STMT:

      PKL_AST_NODE_FREE (PKL_AST_ASS_STMT_LVALUE (ast));
      PKL_AST_NODE_FREE (PKL_AST_ASS_STMT_EXP (ast));
      break;

    case PKL_AST_IF_STMT:

      PKL_AST_NODE_FREE (PKL_AST_IF_STMT_EXP (ast));
      PKL_AST_NODE_FREE (PKL_AST_IF_STMT_THEN_STMT (ast));
      PKL_AST_NODE_FREE (PKL_AST_IF_STMT_ELSE_STMT (ast));
      break;

    case PKL_AST_LOOP_STMT:

      PKL_AST_NODE_FREE (PKL_AST_LOOP_STMT_ITERATOR (ast));
      PKL_AST_NODE_FREE (PKL_AST_LOOP_STMT_CONDITION (ast));
      PKL_AST_NODE_FREE (PKL_AST_LOOP_STMT_BODY (ast));
      PKL_AST_NODE_FREE (PKL_AST_LOOP_STMT_HEAD (ast));
      PKL_AST_NODE_FREE (PKL_AST_LOOP_STMT_TAIL (ast));

      break;

    case PKL_AST_LOOP_STMT_ITERATOR:

      PKL_AST_NODE_FREE (PKL_AST_LOOP_STMT_ITERATOR_DECL (ast));
      PKL_AST_NODE_FREE (PKL_AST_LOOP_STMT_ITERATOR_CONTAINER (ast));

      break;

    case PKL_AST_RETURN_STMT:

      PKL_AST_NODE_FREE (PKL_AST_RETURN_STMT_EXP (ast));
      break;

    case PKL_AST_EXP_STMT:

      PKL_AST_NODE_FREE (PKL_AST_EXP_STMT_EXP (ast));
      break;

    case PKL_AST_TRY_STMT:

      PKL_AST_NODE_FREE (PKL_AST_TRY_STMT_BODY (ast));
      PKL_AST_NODE_FREE (PKL_AST_TRY_STMT_HANDLER (ast));
      PKL_AST_NODE_FREE (PKL_AST_TRY_STMT_ARG (ast));
      PKL_AST_NODE_FREE (PKL_AST_TRY_STMT_EXP (ast));
      break;

    case PKL_AST_TRY_STMT_BODY:

      PKL_AST_NODE_FREE (PKL_AST_TRY_STMT_BODY_CODE (ast));
      break;

    case PKL_AST_TRY_STMT_HANDLER:

      PKL_AST_NODE_FREE (PKL_AST_TRY_STMT_HANDLER_CODE (ast));
      break;

    case PKL_AST_FORMAT_ARG:
      VISIT_AND_FREE (PKL_AST_FORMAT_ARG_SUFFIX (ast));
      VISIT_AND_FREE (PKL_AST_FORMAT_ARG_BEGIN_SC (ast));
      VISIT_AND_FREE (PKL_AST_FORMAT_ARG_END_SC (ast));
      PKL_AST_NODE_FREE (PKL_AST_FORMAT_ARG_EXP (ast));
      break;

    case PKL_AST_FORMAT:
      {
        VISIT_AND_FREE (PKL_AST_FORMAT_PREFIX (ast));
        for (t = PKL_AST_FORMAT_ARGS (ast); t; t = n)
          {
            n = PKL_AST_CHAIN (t);
            PKL_AST_NODE_FREE (t);
          }
        for (t = PKL_AST_FORMAT_TYPES (ast); t; t = n)
          {
            n = PKL_AST_CHAIN (t);
            PKL_AST_NODE_FREE (t);
          }
        PKL_AST_NODE_FREE (PKL_AST_FORMAT_FMT (ast));
        break;
      }

    case PKL_AST_PRINT_STMT:
      {
        PKL_AST_NODE_FREE (PKL_AST_PRINT_STMT_STR_EXP (ast));
        PKL_AST_NODE_FREE (PKL_AST_PRINT_STMT_FORMAT (ast));
        break;
      }

    case PKL_AST_BREAK_CONTINUE_STMT:
      break;


    case PKL_AST_RAISE_STMT:
      PKL_AST_NODE_FREE (PKL_AST_RAISE_STMT_EXP (ast));
      break;

    case PKL_AST_ASM_STMT:
      PKL_AST_NODE_FREE (PKL_AST_ASM_STMT_TEMPLATE (ast));

      for (t = PKL_AST_ASM_STMT_INPUTS (ast); t; t = n)
        {
          n = PKL_AST_CHAIN (t);
          PKL_AST_NODE_FREE (t);
        }

      for (t = PKL_AST_ASM_STMT_OUTPUTS (ast); t; t = n)
        {
          n = PKL_AST_CHAIN (t);
          PKL_AST_NODE_FREE (t);
        }

      break;

    case PKL_AST_NULL_STMT:
      break;

    case PKL_AST_INTEGER:
      break;

    default:
      PK_UNREACHABLE ();
    }

  PKL_AST_NODE_FREE (PKL_AST_TYPE (ast));

  /* Free this node, to match the mark above.  */
  free (ast);

#undef VISIT_AND_FREE
#undef PKL_AST_NODE_FREE
}

/* Free all allocated resources used by AST.  Note that nodes marked
   as "registered", as well as their children, are not disposed.  */

void
pkl_ast_node_free (pkl_ast_node ast)
{
  gl_set_t visitations = gl_set_create_empty (GL_LINKEDHASH_SET,
                                              NULL, NULL, NULL);
  pkl_ast_node_free_1 (visitations, ast);
  gl_set_free (visitations);
}

/* This macro shouldn't be invoked outside of the implementation of the
   node_free walker, other users should be calling pkl_ast_node_free.  */

/* Allocate and initialize a new AST and return it.  */

pkl_ast
pkl_ast_init (void)
{
  struct pkl_ast *ast;

  /* Allocate a new AST and initialize it to 0.  */
  ast = xzalloc (sizeof (struct pkl_ast));

  return ast;
}

/* Free all the memory allocated to store the nodes of an AST.  */

void
pkl_ast_free (pkl_ast ast)
{
  if (ast == NULL)
    return;

  pkl_ast_node_free (ast->ast);
  free (ast->buffer);
  free (ast->filename);
  free (ast);
}

pkl_ast_node
pkl_ast_reverse (pkl_ast_node ast)
{
  pkl_ast_node prev = NULL, decl, next;

  ast = ASTDEREF (ast);
  for (decl = ast; decl != NULL; decl = next)
    {
      next = PKL_AST_CHAIN (decl);
      next = ASTDEREF (next);
      PKL_AST_CHAIN (decl) = ASTREF (prev);
      prev = decl;
    }

  return prev;
}

pkl_ast_node
pkl_ast_get_struct_type_field (pkl_ast_node struct_type,
                               const char *field_name)
{
  pkl_ast_node field = PKL_AST_TYPE_S_ELEMS (struct_type);

  for (field = PKL_AST_TYPE_S_ELEMS (struct_type);
       field;
       field = PKL_AST_CHAIN (field))
    {
      if (PKL_AST_CODE (field) == PKL_AST_STRUCT_TYPE_FIELD)
        {
          pkl_ast_node fname = PKL_AST_STRUCT_TYPE_FIELD_NAME (field);

          if (fname && STREQ (PKL_AST_IDENTIFIER_POINTER (fname),
                              field_name))
            return field;
        }
    }

  return NULL;

}

pkl_ast_node
pkl_ast_get_struct_type_method (pkl_ast_node struct_type,
                                const char *method_name)
{
  pkl_ast_node decl = PKL_AST_TYPE_S_ELEMS (struct_type);

  for (decl = PKL_AST_TYPE_S_ELEMS (struct_type);
       decl;
       decl = PKL_AST_CHAIN (decl))
    {
      if (PKL_AST_CODE (decl) == PKL_AST_DECL
          && PKL_AST_FUNC_METHOD_P (PKL_AST_DECL_INITIAL (decl)))
        {
          pkl_ast_node decl_name = PKL_AST_DECL_NAME (decl);

          if (decl_name
              && STREQ (PKL_AST_IDENTIFIER_POINTER (decl_name),
                        method_name))
            return decl;
        }
    }

  return NULL;
}

pkl_ast_node
pkl_ast_type_incr_step (pkl_ast ast, pkl_ast_node type, int float_p)
{
  pkl_ast_node step = NULL;

  assert (PKL_AST_CODE (type) == PKL_AST_TYPE);

  if (float_p)
    {
      assert (PKL_AST_TYPE_CODE (type) == PKL_TYPE_INTEGRAL);

      /* We need to use the IEEE754 representation of 1.0 for 32-bit and 64-bit
         numbers.  */
      step = pkl_ast_make_integer (ast, PKL_AST_TYPE_I_SIZE (type) == 32
                                            ? 0x3f800000
                                            : 0x3ff0000000000000);
      PKL_AST_TYPE (step) = ASTREF (type);

      return step;
    }

  switch (PKL_AST_TYPE_CODE (type))
    {
    case PKL_TYPE_INTEGRAL:
      {
        /* The obvious step for integral types is 1, of the same
           type.  */
        step = pkl_ast_make_integer (ast, 1);
        PKL_AST_TYPE (step) = ASTREF (type);
        break;
      }
    case PKL_TYPE_OFFSET:
      {
        /* The step for an offset type is one unit.  */
        pkl_ast_node one = pkl_ast_make_integer (ast, 1);

        PKL_AST_TYPE (one) = PKL_AST_TYPE_O_BASE_TYPE (type);
        step = pkl_ast_make_offset (ast, one,
                                    PKL_AST_TYPE_O_UNIT (type));
        PKL_AST_TYPE (step) = ASTREF (type);
        break;
      }
    default:
      break;
    }

  return step;
}

int
pkl_ast_lvalue_p (pkl_ast_node node)
{
  switch (PKL_AST_CODE (node))
    {
    case PKL_AST_VAR:
    case PKL_AST_MAP:
      /* Variable references and maps can always be used as
         l-values.  */
      return 1;
      break;
    case PKL_AST_STRUCT_REF:
      /* A field reference can be used as a l-value if the referred
         struct is itself a l-value.  */
      return pkl_ast_lvalue_p (PKL_AST_STRUCT_REF_STRUCT (node));
      break;
    case PKL_AST_INDEXER:
      /* An indexer can be used as a l-value if the referred entity is
         an array, and it is itself a l-value.  */
      {
        pkl_ast_node entity = PKL_AST_INDEXER_ENTITY (node);
        pkl_ast_node entity_type = PKL_AST_TYPE (entity);

        if (PKL_AST_TYPE_CODE (entity_type) == PKL_TYPE_ARRAY)
          return pkl_ast_lvalue_p (entity);

        break;
      }
    case PKL_AST_EXP:
      if (PKL_AST_EXP_CODE (node) == PKL_AST_OP_BCONC)
        return (pkl_ast_lvalue_p (PKL_AST_EXP_OPERAND (node, 0))
                && pkl_ast_lvalue_p (PKL_AST_EXP_OPERAND (node, 1)));
      break;
    default:
      break;
    }

  return 0;
}

char *
pkl_ast_format_loc (const char *filename, pkl_ast_loc loc)
{
  char *s = NULL;

  assert (PKL_AST_LOC_VALID (loc));
  if (asprintf (&s, "%s:%d:%d",
                filename ? filename : "<stdin>",
                loc.first_line, loc.first_column) == -1)
    return NULL;

  return s;
}

/* Transform l-value bconc operators from this:

   a:::b:::...:::z = EXP;

   Into this:

   {
     a = EXP .>> D_A;
     b = EXP .>> D_B;
     ...
     z = EXP;
   }

   Where a, b, ..., z are valid l-values as per pkl_ast_lvalue_p.

   This function assumes that the total width of a, b, ..., z doesn't
   exceeds 64-bit.  Both M_ and D_ values can be determined at
   compile-time.  */

static int
pkl_ast_handle_bconc_ass_stmt_1 (pkl_ast ast,
                                 pkl_ast_node comp_stmt,
                                 pkl_ast_node bconc_exp,
                                 pkl_ast_node rvalue_exp,
                                 int shift)
{
  int i;

  for (i = 0; i < 2; ++i)
    {
      pkl_ast_node operand = PKL_AST_EXP_OPERAND (bconc_exp, i);

      switch (PKL_AST_CODE (operand))
        {
        case PKL_AST_EXP:
          /* This is another bit-concatenation operand.  Recurse.  */
          shift = pkl_ast_handle_bconc_ass_stmt_1 (ast, comp_stmt,
                                                   operand, rvalue_exp, shift);
          break;
        default:
          {
            /* This is an l-value.  Append an assignment of a masked
               value with the given shift and increase the shift.  */
            pkl_ast_node ass_stmt, stmts;
            pkl_ast_node rvalue;
            pkl_ast_node shift_node, shift_node_type;
            pkl_ast_node operand_type = PKL_AST_TYPE (operand);
            pkl_ast_node rvalue_exp_type = PKL_AST_TYPE (rvalue_exp);

            /* Decrease shift by the size of the operand.  */
            assert (PKL_AST_TYPE_CODE (operand_type) == PKL_TYPE_INTEGRAL);
            shift -= PKL_AST_TYPE_I_SIZE (operand_type);

            shift_node_type = pkl_ast_make_integral_type (ast, 32, 1);
            shift_node = pkl_ast_make_integer (ast, shift);
            PKL_AST_TYPE (shift_node) = ASTREF (shift_node_type);

            rvalue = pkl_ast_make_binary_exp (ast,
                                              PKL_AST_OP_SR,
                                              rvalue_exp, shift_node);
            PKL_AST_TYPE (rvalue) = ASTREF (rvalue_exp_type);

            if (!pkl_ast_type_equal_p (operand_type, rvalue_exp_type))
              {
                rvalue = pkl_ast_make_cast (ast, operand_type, rvalue);
                PKL_AST_TYPE (rvalue) = ASTREF (operand_type);
              }

            ass_stmt = pkl_ast_make_ass_stmt (ast, operand, rvalue);

            stmts = pkl_ast_chainon (PKL_AST_COMP_STMT_STMTS (comp_stmt), ass_stmt);
            PKL_AST_COMP_STMT_STMTS (comp_stmt) = ASTREF (stmts);
            break;
          }
        }
    }

  return shift;
}

pkl_ast_node
pkl_ast_handle_bconc_ass_stmt (pkl_ast ast, pkl_ast_node ass_stmt)
{
  pkl_ast_node comp_stmt = pkl_ast_make_comp_stmt (ast, NULL);
  pkl_ast_node ass_stmt_exp = PKL_AST_ASS_STMT_EXP (ass_stmt);
  pkl_ast_node ass_stmt_exp_type = PKL_AST_TYPE (ass_stmt_exp);
  pkl_ast_node tmp;

  assert (PKL_AST_TYPE_CODE (ass_stmt_exp_type) == PKL_TYPE_INTEGRAL);

  (void) pkl_ast_handle_bconc_ass_stmt_1 (ast, comp_stmt,
                                          PKL_AST_ASS_STMT_LVALUE (ass_stmt),
                                          ass_stmt_exp,
                                          PKL_AST_TYPE_I_SIZE (ass_stmt_exp_type));

  /* Set the location of comp_stmt and all the new assignments to the whole
     original assignment stmt.  */
  PKL_AST_LOC (comp_stmt) = PKL_AST_LOC (ass_stmt);
  for (tmp = PKL_AST_COMP_STMT_STMTS (comp_stmt); tmp;
       tmp = PKL_AST_CHAIN (tmp))
    PKL_AST_LOC (tmp) = PKL_AST_LOC (ass_stmt);

  return comp_stmt;
}

#ifdef PKL_DEBUG

/* The following macros are commodities to be used to keep the
   `pkl_ast_print' function as readable and easy to update as
   possible.  Do not use them anywhere else.  */

#define IPRINTF(...)                            \
  do                                            \
    {                                           \
      int i;                                    \
      for (i = 0; i < indent; i++)              \
        if (indent >= 2 && i % 2 == 0)          \
          sb_append_c (buffer, "|");            \
        else                                    \
          sb_append_c (buffer, " ");            \
      sb_appendf (buffer, __VA_ARGS__);         \
    } while (0)

#define PRINT_AST_IMM(NAME,MACRO,FMT)                    \
  do                                                     \
    {                                                    \
      IPRINTF (#NAME ":\n");                             \
      IPRINTF ("  " FMT "\n", PKL_AST_##MACRO (ast));    \
    }                                                    \
  while (0)

#define PRINT_AST_SUBAST(NAME,MACRO)                            \
  do                                                            \
    {                                                           \
      IPRINTF (#NAME ":\n");                                    \
      pkl_ast_format_1 (buffer, PKL_AST_##MACRO (ast), indent + 2); \
    }                                                           \
  while (0)

#define PRINT_AST_OPT_IMM(NAME,MACRO,FMT)       \
  if (PKL_AST_##MACRO (ast))                    \
    {                                           \
      PRINT_AST_IMM (NAME, MACRO, FMT);         \
    }

#define PRINT_AST_OPT_SUBAST(NAME,MACRO)        \
  if (PKL_AST_##MACRO (ast))                    \
    {                                           \
      PRINT_AST_SUBAST (NAME, MACRO);           \
    }

#define PRINT_AST_SUBAST_CHAIN(MACRO)           \
  for (child = PKL_AST_##MACRO (ast);           \
       child;                                   \
       child = PKL_AST_CHAIN (child))           \
    {                                           \
      pkl_ast_format_1 (buffer, child, indent + 2); \
    }

/* Auxiliary function used by `pkl_ast_print', defined below.  */

static void
pkl_ast_format_1 (struct string_buffer *buffer,
                  pkl_ast_node ast, int indent)
{
  pkl_ast_node child;
  size_t i;

  if (ast == NULL)
    {
      IPRINTF ("NULL::\n");
      return;
    }

#define PRINT_COMMON_FIELDS                                     \
  do                                                            \
    {                                                           \
      IPRINTF ("uid: %" PRIu64 "\n", PKL_AST_UID (ast));        \
      IPRINTF ("refcount: %d\n", PKL_AST_REFCOUNT (ast));\
      IPRINTF ("location: %d,%d-%d,%d\n",                       \
               PKL_AST_LOC (ast).first_line,                    \
               PKL_AST_LOC (ast).first_column,                  \
               PKL_AST_LOC (ast).last_line,                     \
               PKL_AST_LOC (ast).last_column);                  \
    }                                                           \
  while (0)

  switch (PKL_AST_CODE (ast))
    {
    case PKL_AST_PROGRAM:
      IPRINTF ("PROGRAM::\n");

      PRINT_COMMON_FIELDS;
      PRINT_AST_SUBAST_CHAIN (PROGRAM_ELEMS);
      break;

    case PKL_AST_SRC:
      IPRINTF ("SRC::\n");

      PRINT_COMMON_FIELDS;
      PRINT_AST_IMM (filename, SRC_FILENAME, "%p");
      PRINT_AST_OPT_IMM (*filename, SRC_FILENAME, "%s");
      break;

    case PKL_AST_IDENTIFIER:
      IPRINTF ("IDENTIFIER::\n");

      PRINT_COMMON_FIELDS;
      PRINT_AST_IMM (length, IDENTIFIER_LENGTH, "%zu");
      PRINT_AST_IMM (pointer, IDENTIFIER_POINTER, "%p");
      PRINT_AST_OPT_IMM (*pointer, IDENTIFIER_POINTER, "'%s'");
      break;

    case PKL_AST_INTEGER:
      IPRINTF ("INTEGER::\n");

      PRINT_COMMON_FIELDS;
      PRINT_AST_SUBAST (type, TYPE);
      PRINT_AST_IMM (value, INTEGER_VALUE, "%" PRIu64);
      break;

    case PKL_AST_STRING:
      IPRINTF ("STRING::\n");

      PRINT_COMMON_FIELDS;
      PRINT_AST_SUBAST (type, TYPE);
      PRINT_AST_IMM (length, STRING_LENGTH, "%zu");
      PRINT_AST_IMM (pointer, STRING_POINTER, "%p");
      PRINT_AST_OPT_IMM (*pointer, STRING_POINTER, "'%s'");
      break;

    case PKL_AST_EXP:
      {

#define PKL_DEF_OP(SYM, STRING) STRING,
        static const char *pkl_ast_op_name[] =
          {
#include "pkl-ops.def"
          };
#undef PKL_DEF_OP

        IPRINTF ("EXPRESSION::\n");

        PRINT_COMMON_FIELDS;
        IPRINTF ("opcode: %s\n",
                 pkl_ast_op_name[PKL_AST_EXP_CODE (ast)]);
        if (PKL_AST_EXP_ATTR (ast) != PKL_AST_ATTR_NONE)
          IPRINTF ("attr: %s\n", pkl_attr_name (PKL_AST_EXP_ATTR (ast)));
        IPRINTF ("literal_p: %d\n", PKL_AST_LITERAL_P (ast));
        PRINT_AST_SUBAST (type, TYPE);
        PRINT_AST_IMM (numops, EXP_NUMOPS, "%d");
        IPRINTF ("operands:\n");
        for (i = 0; i < PKL_AST_EXP_NUMOPS (ast); i++)
          pkl_ast_format_1 (buffer, PKL_AST_EXP_OPERAND (ast, i),
                            indent + 2);
        break;
      }

    case PKL_AST_COND_EXP:
      IPRINTF ("COND_EXPRESSION::\n");

      PRINT_COMMON_FIELDS;
      PRINT_AST_SUBAST (condition, COND_EXP_COND);
      PRINT_AST_OPT_SUBAST (thenexp, COND_EXP_THENEXP);
      PRINT_AST_OPT_SUBAST (elseexp, COND_EXP_ELSEEXP);
      break;

    case PKL_AST_STRUCT_FIELD:
      IPRINTF ("STRUCT_FIELD::\n");

      PRINT_COMMON_FIELDS;
      PRINT_AST_SUBAST (type, TYPE);
      PRINT_AST_SUBAST (name, STRUCT_FIELD_NAME);
      PRINT_AST_SUBAST (exp, STRUCT_FIELD_EXP);
      break;

    case PKL_AST_STRUCT:
      IPRINTF ("STRUCT::\n");

      PRINT_COMMON_FIELDS;
      PRINT_AST_SUBAST (type, TYPE);
      PRINT_AST_IMM (nelem, STRUCT_NELEM, "%zu");
      IPRINTF ("elems:\n");
      PRINT_AST_SUBAST_CHAIN (STRUCT_FIELDS);
      break;

    case PKL_AST_ARRAY_INITIALIZER:
      IPRINTF ("ARRAY_INITIALIZER::\n");

      PRINT_COMMON_FIELDS;
      PRINT_AST_SUBAST (index, ARRAY_INITIALIZER_INDEX);
      PRINT_AST_SUBAST (exp, ARRAY_INITIALIZER_EXP);
      break;

    case PKL_AST_ARRAY:
      IPRINTF ("ARRAY::\n");

      PRINT_COMMON_FIELDS;
      PRINT_AST_IMM (nelem, ARRAY_NELEM, "%zu");
      PRINT_AST_IMM (ninitializer, ARRAY_NINITIALIZER, "%zu");
      PRINT_AST_SUBAST (type, TYPE);
      IPRINTF ("initializers:\n");
      PRINT_AST_SUBAST_CHAIN (ARRAY_INITIALIZERS);
      break;

    case PKL_AST_ENUMERATOR:
      IPRINTF ("ENUMERATOR::\n");

      PRINT_COMMON_FIELDS;
      PRINT_AST_SUBAST (identifier, ENUMERATOR_IDENTIFIER);
      PRINT_AST_SUBAST (value, ENUMERATOR_VALUE);
      break;

    case PKL_AST_ENUM:
      IPRINTF ("ENUM::\n");

      PRINT_COMMON_FIELDS;
      PRINT_AST_SUBAST (tag, ENUM_TAG);
      IPRINTF ("values:\n");
      PRINT_AST_SUBAST_CHAIN (ENUM_VALUES);
      break;

    case PKL_AST_TYPE:
      IPRINTF ("TYPE::\n");

      PRINT_COMMON_FIELDS;
      if (PKL_AST_TYPE_NAME (ast))
        {
          PRINT_AST_SUBAST (name, TYPE_NAME);
          PRINT_AST_SUBAST (type, TYPE_L_TYPE);
        }
      else
        {
          IPRINTF ("code:\n");
          switch (PKL_AST_TYPE_CODE (ast))
            {
            case PKL_TYPE_ANY: IPRINTF ("  any\n"); break;
            case PKL_TYPE_INTEGRAL: IPRINTF ("  integral\n"); break;
            case PKL_TYPE_STRING: IPRINTF ("  string\n"); break;
            case PKL_TYPE_ARRAY: IPRINTF ("  array\n"); break;
            case PKL_TYPE_STRUCT: IPRINTF ("  struct\n"); break;
            case PKL_TYPE_FUNCTION: IPRINTF ("  function\n"); break;
            case PKL_TYPE_OFFSET: IPRINTF ("  offset\n"); break;
            default:
              IPRINTF (" unknown (%d)\n", PKL_AST_TYPE_CODE (ast));
              break;
            }
          PRINT_AST_IMM (complete, TYPE_COMPLETE, "%d");
          PRINT_AST_IMM (fallible, TYPE_FALLIBLE, "%d");
          switch (PKL_AST_TYPE_CODE (ast))
            {
            case PKL_TYPE_INTEGRAL:
              PRINT_AST_IMM (signed_p, TYPE_I_SIGNED_P, "%d");
              PRINT_AST_IMM (dyn_p, TYPE_I_DYN_P, "%d");
              PRINT_AST_IMM (size, TYPE_I_SIZE, "%zu");
              break;
            case PKL_TYPE_ARRAY:
              PRINT_AST_SUBAST (bound, TYPE_A_BOUND);
              PRINT_AST_SUBAST (etype, TYPE_A_ETYPE);
              break;
            case PKL_TYPE_STRUCT:
              PRINT_AST_IMM (pinned_p, TYPE_S_PINNED_P, "%d");
              PRINT_AST_IMM (union_p, TYPE_S_UNION_P, "%d");
              PRINT_AST_IMM (nelem, TYPE_S_NELEM, "%zu");
              PRINT_AST_IMM (nfield, TYPE_S_NFIELD, "%zu");
              PRINT_AST_IMM (nfield, TYPE_S_NCFIELD, "%zu");
              PRINT_AST_IMM (ndecl, TYPE_S_NDECL, "%zu");
              PRINT_AST_SUBAST (itype, TYPE_S_ITYPE);
              IPRINTF ("elems:\n");
              PRINT_AST_SUBAST_CHAIN (TYPE_S_ELEMS);
              break;
            case PKL_TYPE_FUNCTION:
              PRINT_AST_IMM (narg, TYPE_F_NARG, "%d");
              IPRINTF ("args:\n");
              PRINT_AST_SUBAST_CHAIN (TYPE_F_ARGS);
              break;
            case PKL_TYPE_OFFSET:
              PRINT_AST_SUBAST (base_type, TYPE_O_BASE_TYPE);
              PRINT_AST_SUBAST (unit, TYPE_O_UNIT);
              PRINT_AST_SUBAST (ref_type, TYPE_O_REF_TYPE);
              break;
            case PKL_TYPE_STRING:
            case PKL_TYPE_ANY:
            default:
              break;
            }
        }
      break;

    case PKL_AST_STRUCT_TYPE_FIELD:
      IPRINTF ("STRUCT_TYPE_FIELD::\n");

      PRINT_COMMON_FIELDS;
      PRINT_AST_SUBAST (name, STRUCT_TYPE_FIELD_NAME);
      PRINT_AST_SUBAST (type, STRUCT_TYPE_FIELD_TYPE);
      PRINT_AST_IMM (computed_p, STRUCT_TYPE_FIELD_COMPUTED_P, "%d");
      PRINT_AST_SUBAST (size, STRUCT_TYPE_FIELD_SIZE);
      PRINT_AST_SUBAST (constraint, STRUCT_TYPE_FIELD_CONSTRAINT);
      PRINT_AST_SUBAST (initializer, STRUCT_TYPE_FIELD_INITIALIZER);
      PRINT_AST_SUBAST (label, STRUCT_TYPE_FIELD_LABEL);
      PRINT_AST_SUBAST (pre, STRUCT_TYPE_FIELD_OPTCOND_PRE);
      PRINT_AST_SUBAST (post, STRUCT_TYPE_FIELD_OPTCOND_POST);
      PRINT_AST_IMM (endian, STRUCT_TYPE_FIELD_ENDIAN, "%d");
      break;

    case PKL_AST_FUNC_TYPE_ARG:
      IPRINTF ("FUNC_TYPE_ARG::\n");

      PRINT_COMMON_FIELDS;
      PRINT_AST_SUBAST (type, FUNC_TYPE_ARG_TYPE);
      PRINT_AST_SUBAST (name, FUNC_TYPE_ARG_NAME);
      PRINT_AST_IMM (optional, FUNC_TYPE_ARG_OPTIONAL, "%d");
      break;

    case PKL_AST_TRIMMER:
      IPRINTF ("TRIMMER::\n");
      PRINT_AST_SUBAST (from, TRIMMER_FROM);
      PRINT_AST_SUBAST (to, TRIMMER_TO);
      PRINT_AST_SUBAST (entity, TRIMMER_ENTITY);
      PRINT_AST_SUBAST (addend, TRIMMER_ADDEND);
      break;

    case PKL_AST_INDEXER:
      IPRINTF ("INDEXER::\n");

      PRINT_COMMON_FIELDS;
      PRINT_AST_SUBAST (type, TYPE);
      PRINT_AST_SUBAST (entity, INDEXER_ENTITY);
      PRINT_AST_SUBAST (index, INDEXER_INDEX);
      break;

    case PKL_AST_FUNC:
      IPRINTF ("FUNC::\n");

      PRINT_COMMON_FIELDS;
      PRINT_AST_IMM (nargs, FUNC_NARGS, "%d");
      PRINT_AST_IMM (method_p, FUNC_METHOD_P, "%d");
      PRINT_AST_SUBAST (ret_type, FUNC_RET_TYPE);
      PRINT_AST_SUBAST_CHAIN (FUNC_ARGS);
      PRINT_AST_SUBAST (first_opt_arg, FUNC_FIRST_OPT_ARG);
      PRINT_AST_SUBAST (body, FUNC_BODY);
      break;

    case PKL_AST_FUNC_ARG:
      IPRINTF ("FUNC_ARG::\n");

      PRINT_COMMON_FIELDS;
      PRINT_AST_SUBAST (type, FUNC_ARG_TYPE);
      PRINT_AST_SUBAST (identifier, FUNC_ARG_IDENTIFIER);
      PRINT_AST_IMM (vararg, FUNC_ARG_VARARG, "%d");
      break;

    case PKL_AST_STRUCT_REF:
      IPRINTF ("STRUCT_REF::\n");

      PRINT_COMMON_FIELDS;
      PRINT_AST_SUBAST (type, TYPE);
      PRINT_AST_SUBAST (struct, STRUCT_REF_STRUCT);
      PRINT_AST_SUBAST (identifier, STRUCT_REF_IDENTIFIER);
      if (PKL_AST_STRUCT_REF_ORIG_TYPE (ast))
        PRINT_AST_SUBAST (orig_type, STRUCT_REF_ORIG_TYPE);
      break;

    case PKL_AST_DECL:
      IPRINTF ("DECL::\n");

      PRINT_COMMON_FIELDS;
      PRINT_AST_IMM (kind, DECL_KIND, "%d");
      PRINT_AST_IMM (immutable_p, DECL_IMMUTABLE_P, "%d");
      if (PKL_AST_DECL_SOURCE (ast))
        PRINT_AST_IMM (source, DECL_SOURCE, "'%s'");
      PRINT_AST_SUBAST (name, DECL_NAME);
      PRINT_AST_SUBAST (initial, DECL_INITIAL);
      PRINT_AST_SUBAST (prev_decl, DECL_PREV_DECL);
      break;

    case PKL_AST_OFFSET:
      IPRINTF ("OFFSET::\n");

      PRINT_COMMON_FIELDS;
      PRINT_AST_SUBAST (type, TYPE);
      PRINT_AST_SUBAST (magnitude, OFFSET_MAGNITUDE);
      PRINT_AST_SUBAST (unit, OFFSET_UNIT);
      break;

    case PKL_AST_CAST:
      IPRINTF ("CAST::\n");

      PRINT_COMMON_FIELDS;
      PRINT_AST_SUBAST (type, TYPE);
      PRINT_AST_SUBAST (cast_type, CAST_TYPE);
      PRINT_AST_SUBAST (exp, CAST_EXP);
      break;

    case PKL_AST_ISA:
      IPRINTF ("ISA::\n");

      PRINT_COMMON_FIELDS;
      PRINT_AST_SUBAST (type, TYPE);
      PRINT_AST_SUBAST (isa_type, ISA_TYPE);
      PRINT_AST_SUBAST (exp, ISA_EXP);
      break;

    case PKL_AST_MAP:
      IPRINTF ("MAP::\n");

      PRINT_COMMON_FIELDS;
      PRINT_AST_IMM (strict_p, MAP_STRICT_P, "%d");
      PRINT_AST_SUBAST (type, TYPE);
      PRINT_AST_SUBAST (map_type, MAP_TYPE);
      PRINT_AST_SUBAST (ios, MAP_IOS);
      PRINT_AST_SUBAST (offset, MAP_OFFSET);
      break;

    case PKL_AST_CONS:
      IPRINTF ("CONS::\n");

      PRINT_COMMON_FIELDS;
      PRINT_AST_SUBAST (type, TYPE);
      PRINT_AST_IMM (cons_kind, CONS_KIND, "%d");
      PRINT_AST_SUBAST (cons_type, CONS_TYPE);
      PRINT_AST_SUBAST (cons_value, CONS_VALUE);
      break;


    case PKL_AST_FUNCALL:
      IPRINTF ("FUNCALL::\n");

      PRINT_COMMON_FIELDS;
      PRINT_AST_SUBAST (function, FUNCALL_FUNCTION);
      IPRINTF ("args:\n");
      PRINT_AST_SUBAST_CHAIN (FUNCALL_ARGS);
      break;

    case PKL_AST_FUNCALL_ARG:
      IPRINTF ("FUNCALL_ARG::\n");

      PRINT_AST_SUBAST (exp, FUNCALL_ARG_EXP);
      PRINT_AST_SUBAST (name, FUNCALL_ARG_NAME);
      PRINT_AST_IMM (first_vararg, FUNCALL_ARG_FIRST_VARARG, "%d");
      break;

    case PKL_AST_VAR:
      IPRINTF ("VAR::\n");

      PRINT_COMMON_FIELDS;
      PRINT_AST_SUBAST (type, TYPE);
      PRINT_AST_IMM (back, VAR_BACK, "%d");
      PRINT_AST_IMM (over, VAR_OVER, "%d");
      break;

    case PKL_AST_LAMBDA:
      IPRINTF ("LAMBDA::\n");

      PRINT_COMMON_FIELDS;
      PRINT_AST_SUBAST (function, LAMBDA_FUNCTION);
      break;

    case PKL_AST_ASM_EXP:
      IPRINTF ("ASM_EXP::\n");

      PRINT_COMMON_FIELDS;
      PRINT_AST_SUBAST (type, ASM_EXP_TYPE);
      PRINT_AST_SUBAST (template, ASM_EXP_TEMPLATE);
      PRINT_AST_SUBAST_CHAIN (ASM_EXP_INPUTS);
      break;

    case PKL_AST_FORMAT_ARG:
      IPRINTF ("FORMAT_ARG::\n");
      PRINT_COMMON_FIELDS;
      if (PKL_AST_FORMAT_ARG_BEGIN_SC (ast))
        PRINT_AST_IMM (begin_sc, FORMAT_ARG_BEGIN_SC, "'%s'");
      if (PKL_AST_FORMAT_ARG_END_SC (ast))
        PRINT_AST_IMM (end_sc, FORMAT_ARG_END_SC, "'%s'");
      if (PKL_AST_FORMAT_ARG_SUFFIX (ast))
        PRINT_AST_IMM (suffix, FORMAT_ARG_SUFFIX, "'%s'");
      PRINT_AST_SUBAST (exp, FORMAT_ARG_EXP);
      break;

    case PKL_AST_FORMAT:
      IPRINTF ("FORMAT::\n");
      PRINT_COMMON_FIELDS;
      if (PKL_AST_FORMAT_PREFIX (ast))
        PRINT_AST_IMM (prefix, FORMAT_PREFIX, "'%s'");
      PRINT_AST_SUBAST (fmt, FORMAT_FMT);
      PRINT_AST_SUBAST_CHAIN (FORMAT_TYPES);
      PRINT_AST_SUBAST_CHAIN (FORMAT_ARGS);
      break;

    case PKL_AST_INCRDECR:
      IPRINTF ("INCRDECR::\n");

      PRINT_COMMON_FIELDS;
      PRINT_AST_IMM (order, INCRDECR_ORDER, "%d");
      PRINT_AST_IMM (sign, INCRDECR_SIGN, "%d");
      PRINT_AST_IMM (float_p, INCRDECR_FLOAT_P, "%d");
      PRINT_AST_SUBAST (exp, INCRDECR_EXP);
      break;

    case PKL_AST_COMP_STMT:
      IPRINTF ("COMP_STMT::\n");

      PRINT_COMMON_FIELDS;
      PRINT_AST_IMM (numvars, COMP_STMT_NUMVARS, "%d");
      IPRINTF ("stmts:\n");
      PRINT_AST_SUBAST_CHAIN (COMP_STMT_STMTS);
      break;

    case PKL_AST_ASS_STMT:
      IPRINTF ("ASS_STMT::\n");

      PRINT_COMMON_FIELDS;
      PRINT_AST_SUBAST (lvalue, ASS_STMT_LVALUE);
      PRINT_AST_SUBAST (exp, ASS_STMT_EXP);
      break;

    case PKL_AST_IF_STMT:
      IPRINTF ("IF_STMT::\n");

      PRINT_COMMON_FIELDS;
      PRINT_AST_SUBAST (exp, IF_STMT_EXP);
      PRINT_AST_SUBAST (then_stmt, IF_STMT_THEN_STMT);
      PRINT_AST_SUBAST (else_stmt, IF_STMT_ELSE_STMT);
      break;

    case PKL_AST_LOOP_STMT:
      IPRINTF ("LOOP_STMT::\n");

      PRINT_COMMON_FIELDS;
      PRINT_AST_IMM (kind, LOOP_STMT_KIND, "%d");
      PRINT_AST_SUBAST (iterator, LOOP_STMT_ITERATOR);
      PRINT_AST_SUBAST (condition, LOOP_STMT_CONDITION);
      PRINT_AST_SUBAST (head, LOOP_STMT_HEAD);
      PRINT_AST_SUBAST (tail, LOOP_STMT_TAIL);
      PRINT_AST_SUBAST (body, LOOP_STMT_BODY);
      break;

    case PKL_AST_LOOP_STMT_ITERATOR:
      IPRINTF ("LOOP_STMT_ITERATOR::\n");

      PRINT_COMMON_FIELDS;
      PRINT_AST_SUBAST (decl, LOOP_STMT_ITERATOR_DECL);
      PRINT_AST_SUBAST (container, LOOP_STMT_ITERATOR_CONTAINER);
      break;

    case PKL_AST_RETURN_STMT:
      IPRINTF ("RETURN_STMT::\n");

      PRINT_COMMON_FIELDS;
      PRINT_AST_SUBAST (exp, RETURN_STMT_EXP);
      break;

    case PKL_AST_EXP_STMT:
      IPRINTF ("EXP_STMT::\n");

      PRINT_COMMON_FIELDS;
      PRINT_AST_SUBAST (exp, EXP_STMT_EXP);
      break;

    case PKL_AST_TRY_STMT_BODY:
      IPRINTF ("TRY_STMT_BODY::\n");

      PRINT_COMMON_FIELDS;
      PRINT_AST_SUBAST (body_code, TRY_STMT_BODY_CODE);
      break;

    case PKL_AST_TRY_STMT_HANDLER:
      IPRINTF ("TRY_STMT_HANDLER::\n");

      PRINT_COMMON_FIELDS;
      PRINT_AST_SUBAST (handler_code, TRY_STMT_HANDLER_CODE);
      break;

    case PKL_AST_TRY_STMT:
      IPRINTF ("TRY_STMT::\n");

      PRINT_COMMON_FIELDS;
      PRINT_AST_IMM (kind, TRY_STMT_KIND, "%d");
      PRINT_AST_SUBAST (body, TRY_STMT_BODY);
      PRINT_AST_SUBAST (handler, TRY_STMT_HANDLER);
      PRINT_AST_SUBAST (arg, TRY_STMT_ARG);
      PRINT_AST_SUBAST (exp, TRY_STMT_EXP);
      break;

    case PKL_AST_PRINT_STMT:
      IPRINTF ("PRINT_STMT::\n");
      PRINT_COMMON_FIELDS;
      if (PKL_AST_PRINT_STMT_STR_EXP (ast))
        PRINT_AST_SUBAST (pexp, PRINT_STMT_STR_EXP);
      if (PKL_AST_PRINT_STMT_FORMAT (ast))
        PRINT_AST_SUBAST (format, PRINT_STMT_FORMAT);
      break;

    case PKL_AST_BREAK_CONTINUE_STMT:
      IPRINTF ("BREAK_CONTINUE_STMT::\n");
      PRINT_COMMON_FIELDS;
      PRINT_AST_IMM (nframes, BREAK_CONTINUE_STMT_NFRAMES, "%d");
      PRINT_AST_IMM (npopes, BREAK_CONTINUE_STMT_NPOPES, "%d");
      break;

    case PKL_AST_RAISE_STMT:
      IPRINTF ("RAISE_STMT::\n");

      PRINT_COMMON_FIELDS;
      PRINT_AST_SUBAST (exp, RAISE_STMT_EXP);
      break;

    case PKL_AST_ASM_STMT:
      IPRINTF ("ASM_STMT::\n");

      PRINT_COMMON_FIELDS;
      PRINT_AST_SUBAST (template, ASM_STMT_TEMPLATE);
      PRINT_AST_SUBAST (inputs, ASM_STMT_INPUTS);
      PRINT_AST_SUBAST (outputs, ASM_STMT_OUTPUTS);
      break;

    case PKL_AST_NULL_STMT:
      IPRINTF ("NULL_STMT::\n");

      PRINT_COMMON_FIELDS;
      break;

    default:
      IPRINTF ("UNKNOWN:: code=%d\n", PKL_AST_CODE (ast));
      break;
    }
}

/* Allocate a string with the printable representation of AST.  If
   there is an error such as out of memory, return NULL.  */

char *
pkl_ast_format (pkl_ast_node ast)
{
  struct string_buffer buffer;

  sb_init (&buffer);
  pkl_ast_format_1 (&buffer, ast, 0);
  return sb_dupfree_c (&buffer);
}

/* Dump a printable representation of AST to the file descriptor FD.
   This function is intended to be useful to debug the PKL
   compiler.  */

void
pkl_ast_print (FILE *fp, pkl_ast_node ast)
{
  char *str = pkl_ast_format (ast);

  if (str == NULL)
    /* The only possible error here is out-of-memory.  */
    xalloc_die ();
  fputs (str, fp);
  free (str);
}

#undef IPRINTF
#undef PRINT_AST_IMM
#undef PRINT_AST_SUBAST
#undef PRINT_AST_OPT_FIELD
#undef PRINT_AST_OPT_SUBAST

#endif /* PKL_DEBUG */
