tree.c

gcc-2.95.3 Linux下最常用的C编译器

     int hashcode;
     tree list;
{
  register struct list_hash *h;

  h = (struct list_hash *) obstack_alloc (&class_obstack, sizeof (struct list_hash));
  h->hashcode = hashcode;
  h->list = list;
  h->next = list_hash_table[hashcode % TYPE_HASH_SIZE];
  list_hash_table[hashcode % TYPE_HASH_SIZE] = h;
}

/* Given list components PURPOSE, VALUE, AND CHAIN, return the canonical
   object for an identical list if one already exists.  Otherwise, build a
   new one, and record it as the canonical object.  */

/* Set to 1 to debug without canonicalization.  Never set by program.  */

static int debug_no_list_hash = 0;

tree
hash_tree_cons (purpose, value, chain)
     tree purpose, value, chain;
{
  struct obstack *ambient_obstack = current_obstack;
  tree t;
  int hashcode = 0;

  if (! debug_no_list_hash)
    {
      hashcode = list_hash (purpose, value, chain);
      t = list_hash_lookup (hashcode, purpose, value, chain);
      if (t)
	return t;
    }

  current_obstack = &class_obstack;

  t = tree_cons (purpose, value, chain);

  /* If this is a new list, record it for later reuse.  */
  if (! debug_no_list_hash)
    list_hash_add (hashcode, t);

  current_obstack = ambient_obstack;
  return t;
}

/* Constructor for hashed lists.  */

tree
hash_tree_chain (value, chain)
     tree value, chain;
{
  return hash_tree_cons (NULL_TREE, value, chain);
}

/* Similar, but used for concatenating two lists.  */

tree
hash_chainon (list1, list2)
     tree list1, list2;
{
  if (list2 == 0)
    return list1;
  if (list1 == 0)
    return list2;
  if (TREE_CHAIN (list1) == NULL_TREE)
    return hash_tree_chain (TREE_VALUE (list1), list2);
  return hash_tree_chain (TREE_VALUE (list1),
			  hash_chainon (TREE_CHAIN (list1), list2));
}

/* Build an association between TYPE and some parameters:

   OFFSET is the offset added to `this' to convert it to a pointer
   of type `TYPE *'

   BINFO is the base binfo to use, if we are deriving from one.  This
   is necessary, as we want specialized parent binfos from base
   classes, so that the VTABLE_NAMEs of bases are for the most derived
   type, instead of the simple type.

   VTABLE is the virtual function table with which to initialize
   sub-objects of type TYPE.

   VIRTUALS are the virtual functions sitting in VTABLE.  */

tree
make_binfo (offset, binfo, vtable, virtuals)
     tree offset, binfo;
     tree vtable, virtuals;
{
  tree new_binfo = make_tree_vec (7);
  tree type;

  if (TREE_CODE (binfo) == TREE_VEC)
    type = BINFO_TYPE (binfo);
  else
    {
      type = binfo;
      binfo = CLASS_TYPE_P (type) ? TYPE_BINFO (binfo) : NULL_TREE;
    }

  TREE_TYPE (new_binfo) = TYPE_MAIN_VARIANT (type);
  BINFO_OFFSET (new_binfo) = offset;
  BINFO_VTABLE (new_binfo) = vtable;
  BINFO_VIRTUALS (new_binfo) = virtuals;
  BINFO_VPTR_FIELD (new_binfo) = NULL_TREE;

  if (binfo && BINFO_BASETYPES (binfo) != NULL_TREE)
    BINFO_BASETYPES (new_binfo) = copy_node (BINFO_BASETYPES (binfo));      
  return new_binfo;
}

/* Return the binfo value for ELEM in TYPE.  */

tree
binfo_value (elem, type)
     tree elem;
     tree type;
{
  if (get_base_distance (elem, type, 0, (tree *)0) == -2)
    compiler_error ("base class `%s' ambiguous in binfo_value",
		    TYPE_NAME_STRING (elem));
  if (elem == type)
    return TYPE_BINFO (type);
  if (TREE_CODE (elem) == RECORD_TYPE && TYPE_BINFO (elem) == type)
    return type;
  return get_binfo (elem, type, 0);
}

/* Return a reversed copy of the BINFO-chain given by PATH.  (If the 
   BINFO_INHERITANCE_CHAIN points from base classes to derived
   classes, it will instead point from derived classes to base
   classes.)  Returns the first node in the reversed chain.  */

tree
reverse_path (path)
     tree path;
{
  register tree prev = NULL_TREE, cur;
  push_expression_obstack ();
  for (cur = path; cur; cur = BINFO_INHERITANCE_CHAIN (cur))
    {
      tree r = copy_node (cur);
      BINFO_INHERITANCE_CHAIN (r) = prev;
      prev = r;
    }
  pop_obstacks ();
  return prev;
}

void
debug_binfo (elem)
     tree elem;
{
  unsigned HOST_WIDE_INT n;
  tree virtuals;

  fprintf (stderr, "type \"%s\"; offset = %ld\n",
	   TYPE_NAME_STRING (BINFO_TYPE (elem)),
	   (long) TREE_INT_CST_LOW (BINFO_OFFSET (elem)));
  fprintf (stderr, "vtable type:\n");
  debug_tree (BINFO_TYPE (elem));
  if (BINFO_VTABLE (elem))
    fprintf (stderr, "vtable decl \"%s\"\n", IDENTIFIER_POINTER (DECL_NAME (BINFO_VTABLE (elem))));
  else
    fprintf (stderr, "no vtable decl yet\n");
  fprintf (stderr, "virtuals:\n");
  virtuals = BINFO_VIRTUALS (elem);

  n = skip_rtti_stuff (&virtuals, BINFO_TYPE (elem));

  while (virtuals)
    {
      tree fndecl = TREE_OPERAND (FNADDR_FROM_VTABLE_ENTRY (TREE_VALUE (virtuals)), 0);
      fprintf (stderr, "%s [%ld =? %ld]\n",
	       IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (fndecl)),
	       (long) n, (long) TREE_INT_CST_LOW (DECL_VINDEX (fndecl)));
      ++n;
      virtuals = TREE_CHAIN (virtuals);
    }
}

/* Initialize an CPLUS_BINDING node that does not live on an obstack. */

tree
binding_init (node)
     struct tree_binding* node;
{
  static struct tree_binding* source;
  if (!source)
    {
      extern struct obstack permanent_obstack;
      push_obstacks (&permanent_obstack, &permanent_obstack);
      source = (struct tree_binding*)make_node (CPLUS_BINDING);
      pop_obstacks ();
    }
  *node = *source;
  TREE_PERMANENT ((tree)node) = 0;
  return (tree)node;
}

int
count_functions (t)
     tree t;
{
  int i;
  if (TREE_CODE (t) == FUNCTION_DECL)
    return 1;
  else if (TREE_CODE (t) == OVERLOAD)
    {
      for (i=0; t; t = OVL_CHAIN (t))
	i++;
      return i;
    }

  my_friendly_abort (359);
  return 0;
}

int
is_overloaded_fn (x)
     tree x;
{
  /* A baselink is also considered an overloaded function.  */
  if (TREE_CODE (x) == OFFSET_REF)
    x = TREE_OPERAND (x, 1);
  if (BASELINK_P (x))
    x = TREE_VALUE (x);
  return (TREE_CODE (x) == FUNCTION_DECL
	  || TREE_CODE (x) == TEMPLATE_ID_EXPR
	  || DECL_FUNCTION_TEMPLATE_P (x)
	  || TREE_CODE (x) == OVERLOAD);
}

int
really_overloaded_fn (x)
     tree x;
{     
  /* A baselink is also considered an overloaded function.  */
  if (TREE_CODE (x) == OFFSET_REF)
    x = TREE_OPERAND (x, 1);
  if (BASELINK_P (x))
    x = TREE_VALUE (x);
  return (TREE_CODE (x) == OVERLOAD 
	  && (TREE_CHAIN (x) != NULL_TREE
	      || DECL_FUNCTION_TEMPLATE_P (OVL_FUNCTION (x))));
}

tree
get_first_fn (from)
     tree from;
{
  my_friendly_assert (is_overloaded_fn (from), 9);
  /* A baselink is also considered an overloaded function. */
  if (BASELINK_P (from))
    from = TREE_VALUE (from);
  return OVL_CURRENT (from);
}

/* Returns nonzero if T is a ->* or .* expression that refers to a
   member function.  */

int
bound_pmf_p (t)
     tree t;
{
  return (TREE_CODE (t) == OFFSET_REF
	  && TYPE_PTRMEMFUNC_P (TREE_TYPE (TREE_OPERAND (t, 1))));
}

/* Return a new OVL node, concatenating it with the old one. */

tree
ovl_cons (decl, chain)
     tree decl;
     tree chain;
{
  tree result = make_node (OVERLOAD);
  TREE_TYPE (result) = unknown_type_node;
  OVL_FUNCTION (result) = decl;
  TREE_CHAIN (result) = chain;
  
  return result;
}

/* Same as ovl_cons, but on the scratch_obstack. */

tree
scratch_ovl_cons (value, chain)
     tree value, chain;
{
  register tree node;
  register struct obstack *ambient_obstack = current_obstack;
  extern struct obstack *expression_obstack;
  current_obstack = expression_obstack;
  node = ovl_cons (value, chain);
  current_obstack = ambient_obstack;
  return node;
}

/* Build a new overloaded function. If this is the first one,
   just return it; otherwise, ovl_cons the _DECLs */

tree
build_overload (decl, chain)
     tree decl;
     tree chain;
{
  if (! chain && TREE_CODE (decl) != TEMPLATE_DECL)
    return decl;
  if (chain && TREE_CODE (chain) != OVERLOAD)
    chain = ovl_cons (chain, NULL_TREE);
  return ovl_cons (decl, chain);
}

/* Returns true iff functions are equivalent. Equivalent functions are
   not identical only if one is a function-local extern function.
   This assumes that function-locals don't have TREE_PERMANENT.  */

static int
equal_functions (fn1, fn2)
     tree fn1;
     tree fn2;
{
  if (!TREE_PERMANENT (fn1) || !TREE_PERMANENT (fn2))
    return decls_match (fn1, fn2);
  return fn1 == fn2;
}

/* True if fn is in ovl. */

int
ovl_member (fn, ovl)
     tree fn;
     tree ovl;
{
  if (ovl == NULL_TREE)
    return 0;
  if (TREE_CODE (ovl) != OVERLOAD)
    return equal_functions (ovl, fn);
  for (; ovl; ovl = OVL_CHAIN (ovl))
    if (equal_functions (OVL_FUNCTION (ovl), fn))
      return 1;
  return 0;
}

int
is_aggr_type_2 (t1, t2)
     tree t1, t2;
{
  if (TREE_CODE (t1) != TREE_CODE (t2))
    return 0;
  return IS_AGGR_TYPE (t1) && IS_AGGR_TYPE (t2);
}

#define PRINT_RING_SIZE 4

char *
lang_printable_name (decl, v)
     tree decl;
     int v;
{
  static tree decl_ring[PRINT_RING_SIZE];
  static char *print_ring[PRINT_RING_SIZE];
  static int ring_counter;
  int i;

  /* Only cache functions.  */
  if (v < 2
      || TREE_CODE (decl) != FUNCTION_DECL
      || DECL_LANG_SPECIFIC (decl) == 0)
    return lang_decl_name (decl, v);

  /* See if this print name is lying around.  */
  for (i = 0; i < PRINT_RING_SIZE; i++)
    if (decl_ring[i] == decl)
      /* yes, so return it.  */
      return print_ring[i];

  if (++ring_counter == PRINT_RING_SIZE)
    ring_counter = 0;

  if (current_function_decl != NULL_TREE)
    {
      if (decl_ring[ring_counter] == current_function_decl)
	ring_counter += 1;
      if (ring_counter == PRINT_RING_SIZE)
	ring_counter = 0;
      if (decl_ring[ring_counter] == current_function_decl)
	my_friendly_abort (106);
    }

  if (print_ring[ring_counter])
    free (print_ring[ring_counter]);

  print_ring[ring_counter] = xstrdup (lang_decl_name (decl, v));
  decl_ring[ring_counter] = decl;
  return print_ring[ring_counter];
}

/* Build the FUNCTION_TYPE or METHOD_TYPE which may throw exceptions
   listed in RAISES.  */

tree
build_exception_variant (type, raises)
     tree type;
     tree raises;
{
  tree v = TYPE_MAIN_VARIANT (type);
  int type_quals = TYPE_QUALS (type);

  for (; v; v = TYPE_NEXT_VARIANT (v))
    {
      tree t;
      tree u;

      if (TYPE_QUALS (v) != type_quals)
	continue;

      for (t = TYPE_RAISES_EXCEPTIONS (v), u = raises;
	   t != NULL_TREE && u != NULL_TREE;
	   t = TREE_CHAIN (t), u = TREE_CHAIN (u))
	if (((TREE_VALUE (t) != NULL_TREE) 
	     != (TREE_VALUE (u) != NULL_TREE))
	    || !same_type_p (TREE_VALUE (t), TREE_VALUE (u)))
	  break;

      if (!t && !u)
	/* There's a memory leak here; RAISES is not freed.  */
	return v;
    }

  /* Need to build a new variant.  */
  v = build_type_copy (type);

  if (raises && ! TREE_PERMANENT (raises))
    raises = copy_to_permanent (raises);

  TYPE_RAISES_EXCEPTIONS (v) = raises;
  return v;
}

/* Given a TEMPLATE_TEMPLATE_PARM node T, create a new one together with its 
   lang_specific field and its corresponding TEMPLATE_DECL node */

tree
copy_template_template_parm (t)
     tree t;
{
  tree template = TYPE_NAME (t);
  tree t2;

  /* Make sure these end up on the permanent_obstack.  */
  push_obstacks_nochange ();
  end_temporary_allocation ();
  
  t2 = make_lang_type (TEMPLATE_TEMPLATE_PARM);
  template = copy_node (template);
  copy_lang_decl (template);

  pop_obstacks ();

  TREE_TYPE (template) = t2;
  TYPE_NAME (t2) = template;
  TYPE_STUB_DECL (t2) = template;

  /* No need to copy these */
  TYPE_FIELDS (t2) = TYPE_FIELDS (t);
  TEMPLATE_TEMPLATE_PARM_TEMPLATE_INFO (t2) 
    = TEMPLATE_TEMPLATE_PARM_TEMPLATE_INFO (t);
  return t2;
}

/* Walk through the tree structure T, applying func.  If func ever returns
   non-null, return that value.  */

tree
search_tree (t, func)
     tree t;
     tree (*func) PROTO((tree));
{
#define TRY(ARG) if (tmp=search_tree (ARG, func), tmp != NULL_TREE) return tmp

  tree tmp;

  if (t == NULL_TREE)
    return t;

  if (tmp = func (t), tmp != NULL_TREE)
    return tmp;

  switch (TREE_CODE (t))
    {
    case ERROR_MARK:
      break;

    case IDENTIFIER_NODE: