Function simplicity_mallocTypeInference

src/simplicity/typeInference.c:561–602

If the Simplicity DAG, 'dag', has a principal type (including constraints due to sharing of subexpressions), * then allocate a well-formed type DAG containing all the types needed for all the subexpressions of 'dag', * with all free type variables instantiated at ONE, and set '*type_dag' to this allocation, * and update the '.sourceType' and '.targetType' fields within each node of the 'dag' 't

 *                if the return value is not 'SIMPLICITY_NO_ERROR' then 'NULL == *type_dag'
 */
simplicity_err simplicity_mallocTypeInference(type** type_dag, simplicity_callback_mallocBoundVars mallocBoundVars, dag_node* dag, const uint_fast32_t len, const combinator_counters* census) {
  *type_dag = NULL;
  static_assert(DAG_LEN_MAX <= SIZE_MAX / sizeof(unification_arrow), "arrow array too large.");
  static_assert(1 <= DAG_LEN_MAX, "DAG_LEN_MAX is zero.");
  static_assert(DAG_LEN_MAX - 1 <= UINT32_MAX, "arrow array index does not fit in uint32_t.");
  simplicity_assert(1 <= len);
  simplicity_assert(len <= DAG_LEN_MAX);
  unification_arrow* arrow = simplicity_malloc(len * sizeof(unification_arrow));
  unification_var* bound_var = NULL;
  size_t word256_ix, extra_var_start;
  const size_t orig_bindings_used = mallocBoundVars(&bound_var, &word256_ix, &extra_var_start, max_extra_vars(census));
  size_t bindings_used = orig_bindings_used;

  static_assert(1 <= NUMBER_OF_TYPENAMES_MAX, "NUMBER_OF_TYPENAMES_MAX is zero.");
  simplicity_assert(orig_bindings_used <= NUMBER_OF_TYPENAMES_MAX - 1);

  simplicity_err result = arrow && bound_var ? SIMPLICITY_NO_ERROR : SIMPLICITY_ERR_MALLOC;
  if (IS_OK(result)) {
    result = typeInference(arrow, dag, len, bound_var + extra_var_start, bound_var, word256_ix, &bindings_used);
  }
  if (IS_OK(result)) {
    /* :TODO: constrain the root of the dag to be a Simplicity program: ONE |- ONE */
    static_assert(TYPE_DAG_LEN_MAX <= SIZE_MAX / sizeof(type), "type_dag array too large.");
    static_assert(1 <= TYPE_DAG_LEN_MAX, "TYPE_DAG_LEN_MAX is zero.");
    static_assert(TYPE_DAG_LEN_MAX - 1 <= UINT32_MAX, "type_dag array index does not fit in uint32_t.");
    /* 'bindings_used' is at most 4*len plus the initial value of 'bindings_used' set by 'mallocBoundVars'. */
    simplicity_assert(bindings_used <= orig_bindings_used + 4*len);
    *type_dag = simplicity_malloc((1 + bindings_used) * sizeof(type));
    result = *type_dag ? SIMPLICITY_NO_ERROR : SIMPLICITY_ERR_MALLOC;
    if (IS_OK(result)) {
      result = freezeTypes(*type_dag, dag, arrow, len);
    }
    if (!IS_OK(result)) {
      simplicity_free(*type_dag);
      *type_dag = NULL;
    }
  }

  simplicity_free(arrow);
  simplicity_free(bound_var);
  return result;
}