tree.c

gcc-2.95.3 Linux下最常用的C编译器

static tree
perm_manip (t)
     tree t;
{
  if (TREE_PERMANENT (t))
    return t;

  /* Support `void f () { extern int i; A<&i> a; }' */
  if ((TREE_CODE (t) == VAR_DECL || TREE_CODE (t) == FUNCTION_DECL)
      && TREE_PUBLIC (t))
    {
      t = copy_node (t);

      /* copy_rtx won't make a new SYMBOL_REF, so call make_decl_rtl again.  */
      DECL_RTL (t) = 0;
      make_decl_rtl (t, NULL_PTR, 1);

      return t;
    }
  return NULL_TREE;
}

/* Assuming T is a node built bottom-up, make it all exist on
   permanent obstack, if it is not permanent already.  */

tree
copy_to_permanent (t)
     tree t;
{
  if (t == NULL_TREE || TREE_PERMANENT (t))
    return t;

  push_obstacks_nochange ();
  end_temporary_allocation ();

  t = mapcar (t, perm_manip);

  pop_obstacks ();

  return t;
}

#ifdef GATHER_STATISTICS
extern int depth_reached;
#endif

void
print_lang_statistics ()
{
  extern struct obstack decl_obstack;
  print_obstack_statistics ("class_obstack", &class_obstack);
  print_obstack_statistics ("decl_obstack", &decl_obstack);
  print_search_statistics ();
  print_class_statistics ();
#ifdef GATHER_STATISTICS
  fprintf (stderr, "maximum template instantiation depth reached: %d\n",
	   depth_reached);
#endif
}

/* This is used by the `assert' macro.  It is provided in libgcc.a,
   which `cc' doesn't know how to link.  Note that the C++ front-end
   no longer actually uses the `assert' macro (instead, it calls
   my_friendly_assert).  But all of the back-end files still need this.  */

void
__eprintf (string, expression, line, filename)
     const char *string;
     const char *expression;
     unsigned line;
     const char *filename;
{
  fprintf (stderr, string, expression, line, filename);
  fflush (stderr);
  abort ();
}

/* Return, as an INTEGER_CST node, the number of elements for TYPE
   (which is an ARRAY_TYPE).  This counts only elements of the top
   array.  */

tree
array_type_nelts_top (type)
     tree type;
{
  return fold (build (PLUS_EXPR, sizetype,
		      array_type_nelts (type),
		      integer_one_node));
}

/* Return, as an INTEGER_CST node, the number of elements for TYPE
   (which is an ARRAY_TYPE).  This one is a recursive count of all
   ARRAY_TYPEs that are clumped together.  */

tree
array_type_nelts_total (type)
     tree type;
{
  tree sz = array_type_nelts_top (type);
  type = TREE_TYPE (type);
  while (TREE_CODE (type) == ARRAY_TYPE)
    {
      tree n = array_type_nelts_top (type);
      sz = fold (build (MULT_EXPR, sizetype, sz, n));
      type = TREE_TYPE (type);
    }
  return sz;
}

static
tree
bot_manip (t)
     tree t;
{
  if (TREE_CODE (t) != TREE_LIST && ! TREE_SIDE_EFFECTS (t))
    return t;
  else if (TREE_CODE (t) == TARGET_EXPR)
    {
      if (TREE_CODE (TREE_OPERAND (t, 1)) == AGGR_INIT_EXPR)
	{
	  mark_used (TREE_OPERAND (TREE_OPERAND (TREE_OPERAND (t, 1), 0), 0));
	  return build_cplus_new
	    (TREE_TYPE (t), break_out_target_exprs (TREE_OPERAND (t, 1)));
	}
      t = copy_node (t);
      TREE_OPERAND (t, 0) = build (VAR_DECL, TREE_TYPE (t));
      layout_decl (TREE_OPERAND (t, 0), 0);
      return t;
    }
  else if (TREE_CODE (t) == CALL_EXPR)
    mark_used (TREE_OPERAND (TREE_OPERAND (t, 0), 0));

  return NULL_TREE;
}
  
/* Actually, we'll just clean out the target exprs for the moment.  */

tree
break_out_target_exprs (t)
     tree t;
{
  return mapcar (t, bot_manip);
}

/* Obstack used for allocating nodes in template function and variable
   definitions.  */

/* Similar to `build_nt', except we build
   on the permanent_obstack, regardless.  */

tree
build_min_nt VPROTO((enum tree_code code, ...))
{
#ifndef __STDC__
  enum tree_code code;
#endif
  register struct obstack *ambient_obstack = expression_obstack;
  va_list p;
  register tree t;
  register int length;
  register int i;

  VA_START (p, code);

#ifndef __STDC__
  code = va_arg (p, enum tree_code);
#endif

  expression_obstack = &permanent_obstack;

  t = make_node (code);
  length = tree_code_length[(int) code];
  TREE_COMPLEXITY (t) = lineno;

  for (i = 0; i < length; i++)
    {
      tree x = va_arg (p, tree);
      TREE_OPERAND (t, i) = copy_to_permanent (x);
    }

  va_end (p);
  expression_obstack = ambient_obstack;
  return t;
}

/* Similar to `build', except we build
   on the permanent_obstack, regardless.  */

tree
build_min VPROTO((enum tree_code code, tree tt, ...))
{
#ifndef __STDC__
  enum tree_code code;
  tree tt;
#endif
  register struct obstack *ambient_obstack = expression_obstack;
  va_list p;
  register tree t;
  register int length;
  register int i;

  VA_START (p, tt);

#ifndef __STDC__
  code = va_arg (p, enum tree_code);
  tt = va_arg (p, tree);
#endif

  expression_obstack = &permanent_obstack;

  t = make_node (code);
  length = tree_code_length[(int) code];
  TREE_TYPE (t) = copy_to_permanent (tt);
  TREE_COMPLEXITY (t) = lineno;

  for (i = 0; i < length; i++)
    {
      tree x = va_arg (p, tree);
      TREE_OPERAND (t, i) = copy_to_permanent (x);
    }

  va_end (p);
  expression_obstack = ambient_obstack;
  return t;
}

/* Same as `tree_cons' but make a permanent object.  */

tree
min_tree_cons (purpose, value, chain)
     tree purpose, value, chain;
{
  register tree node;
  register struct obstack *ambient_obstack = current_obstack;
  current_obstack = &permanent_obstack;

  node = tree_cons (copy_to_permanent (purpose),
		    copy_to_permanent (value), chain);
  current_obstack = ambient_obstack;
  return node;
}

tree
get_type_decl (t)
     tree t;
{
  if (TREE_CODE (t) == TYPE_DECL)
    return t;
  if (TREE_CODE_CLASS (TREE_CODE (t)) == 't')
    return TYPE_STUB_DECL (t);
  
  my_friendly_abort (42);

  /* Stop compiler from complaining control reaches end of non-void function.  */
  return 0;
}

int
can_free (obstack, t)
     struct obstack *obstack;
     tree t;
{
  int size = 0;

  if (TREE_CODE (t) == TREE_VEC)
    size = (TREE_VEC_LENGTH (t)-1) * sizeof (tree) + sizeof (struct tree_vec);
  else
    my_friendly_abort (42);

#define ROUND(x) ((x + obstack_alignment_mask (obstack)) \
		  & ~ obstack_alignment_mask (obstack))
  if ((char *)t + ROUND (size) == obstack_next_free (obstack))
    return 1;
#undef ROUND

  return 0;
}

/* Return first vector element whose BINFO_TYPE is ELEM.
   Return 0 if ELEM is not in VEC.  VEC may be NULL_TREE.  */

tree
vec_binfo_member (elem, vec)
     tree elem, vec;
{
  int i;

  if (vec)
    for (i = 0; i < TREE_VEC_LENGTH (vec); ++i)
      if (same_type_p (elem, BINFO_TYPE (TREE_VEC_ELT (vec, i))))
	return TREE_VEC_ELT (vec, i);

  return NULL_TREE;
}

/* Kludge around the fact that DECL_CONTEXT for virtual functions returns
   the wrong thing for decl_function_context.  Hopefully the uses in the
   backend won't matter, since we don't need a static chain for local class
   methods.  FIXME!  */

tree
hack_decl_function_context (decl)
     tree decl;
{
  if (TREE_CODE (decl) == FUNCTION_DECL && DECL_FUNCTION_MEMBER_P (decl))
    return decl_function_context (TYPE_MAIN_DECL (DECL_CLASS_CONTEXT (decl)));
  return decl_function_context (decl);
}

/* Returns the namespace that contains DECL, whether directly or
   indirectly.  */

tree
decl_namespace_context (decl)
     tree decl;
{
  while (1)
    {
      if (TREE_CODE (decl) == NAMESPACE_DECL)
	return decl;
      else if (TYPE_P (decl))
	decl = CP_DECL_CONTEXT (TYPE_MAIN_DECL (decl));
      else
	decl = CP_DECL_CONTEXT (decl);
    }
}

/* Return truthvalue of whether T1 is the same tree structure as T2.
   Return 1 if they are the same.
   Return 0 if they are understandably different.
   Return -1 if either contains tree structure not understood by
   this function.  */

int
cp_tree_equal (t1, t2)
     tree t1, t2;
{
  register enum tree_code code1, code2;
  int cmp;

  if (t1 == t2)
    return 1;
  if (t1 == 0 || t2 == 0)
    return 0;

  code1 = TREE_CODE (t1);
  code2 = TREE_CODE (t2);

  if (code1 == NOP_EXPR || code1 == CONVERT_EXPR || code1 == NON_LVALUE_EXPR)
    {
      if (code2 == NOP_EXPR || code2 == CONVERT_EXPR || code2 == NON_LVALUE_EXPR)
	return cp_tree_equal (TREE_OPERAND (t1, 0), TREE_OPERAND (t2, 0));
      else
	return cp_tree_equal (TREE_OPERAND (t1, 0), t2);
    }
  else if (code2 == NOP_EXPR || code2 == CONVERT_EXPR
	   || code2 == NON_LVALUE_EXPR)
    return cp_tree_equal (t1, TREE_OPERAND (t2, 0));

  if (code1 != code2)
    return 0;

  switch (code1)
    {
    case INTEGER_CST:
      return TREE_INT_CST_LOW (t1) == TREE_INT_CST_LOW (t2)
	&& TREE_INT_CST_HIGH (t1) == TREE_INT_CST_HIGH (t2);

    case REAL_CST:
      return REAL_VALUES_EQUAL (TREE_REAL_CST (t1), TREE_REAL_CST (t2));

    case STRING_CST:
      return TREE_STRING_LENGTH (t1) == TREE_STRING_LENGTH (t2)
	&& !bcmp (TREE_STRING_POINTER (t1), TREE_STRING_POINTER (t2),
		  TREE_STRING_LENGTH (t1));

    case CONSTRUCTOR:
      /* We need to do this when determining whether or not two
	 non-type pointer to member function template arguments
	 are the same.  */
      if (!(same_type_p (TREE_TYPE (t1), TREE_TYPE (t2))
	    /* The first operand is RTL.  */
	    && TREE_OPERAND (t1, 0) == TREE_OPERAND (t2, 0)))
	return 0;
      return cp_tree_equal (TREE_OPERAND (t1, 1), TREE_OPERAND (t2, 1));

    case TREE_LIST:
      cmp = cp_tree_equal (TREE_PURPOSE (t1), TREE_PURPOSE (t2));
      if (cmp <= 0)
	return cmp;
      cmp = cp_tree_equal (TREE_VALUE (t1), TREE_VALUE (t2));
      if (cmp <= 0)
	return cmp;
      return cp_tree_equal (TREE_CHAIN (t1), TREE_CHAIN (t2));

    case SAVE_EXPR:
      return cp_tree_equal (TREE_OPERAND (t1, 0), TREE_OPERAND (t2, 0));

    case CALL_EXPR:
      cmp = cp_tree_equal (TREE_OPERAND (t1, 0), TREE_OPERAND (t2, 0));
      if (cmp <= 0)
	return cmp;
      return simple_cst_list_equal (TREE_OPERAND (t1, 1), TREE_OPERAND (t2, 1));

    case TARGET_EXPR:
      /* Special case: if either target is an unallocated VAR_DECL,
	 it means that it's going to be unified with whatever the
	 TARGET_EXPR is really supposed to initialize, so treat it
	 as being equivalent to anything.  */
      if ((TREE_CODE (TREE_OPERAND (t1, 0)) == VAR_DECL
	   && DECL_NAME (TREE_OPERAND (t1, 0)) == NULL_TREE
	   && DECL_RTL (TREE_OPERAND (t1, 0)) == 0)
	  || (TREE_CODE (TREE_OPERAND (t2, 0)) == VAR_DECL
	      && DECL_NAME (TREE_OPERAND (t2, 0)) == NULL_TREE
	      && DECL_RTL (TREE_OPERAND (t2, 0)) == 0))
	cmp = 1;
      else
	cmp = cp_tree_equal (TREE_OPERAND (t1, 0), TREE_OPERAND (t2, 0));
      if (cmp <= 0)
	return cmp;
      return cp_tree_equal (TREE_OPERAND (t1, 1), TREE_OPERAND (t2, 1));

    case WITH_CLEANUP_EXPR:
      cmp = cp_tree_equal (TREE_OPERAND (t1, 0), TREE_OPERAND (t2, 0));
      if (cmp <= 0)
	return cmp;
      return cp_tree_equal (TREE_OPERAND (t1, 2), TREE_OPERAND (t1, 2));

    case COMPONENT_REF:
      if (TREE_OPERAND (t1, 1) == TREE_OPERAND (t2, 1))
	return cp_tree_equal (TREE_OPERAND (t1, 0), TREE_OPERAND (t2, 0));
      return 0;

    case VAR_DECL:
    case PARM_DECL:
    case CONST_DECL:
    case FUNCTION_DECL:
      return 0;

    case TEMPLATE_PARM_INDEX:
      return TEMPLATE_PARM_IDX (t1) == TEMPLATE_PARM_IDX (t2)
	&& TEMPLATE_PARM_LEVEL (t1) == TEMPLATE_PARM_LEVEL (t2);

    case SIZEOF_EXPR:
    case ALIGNOF_EXPR:
      if (TREE_CODE (TREE_OPERAND (t1, 0)) != TREE_CODE (TREE_OPERAND (t2, 0)))
	return 0;
      if (TREE_CODE_CLASS (TREE_CODE (TREE_OPERAND (t1, 0))) == 't')
	return same_type_p (TREE_OPERAND (t1, 0), TREE_OPERAND (t2, 0));
      break;

    case PTRMEM_CST:
      /* Two pointer-to-members are the same if they point to the same
	 field or function in the same class.  */
      return (PTRMEM_CST_MEMBER (t1) == PTRMEM_CST_MEMBER (t2)
	      && same_type_p (PTRMEM_CST_CLASS (t1), PTRMEM_CST_CLASS (t2)));

    default:
      break;
    }

  switch (TREE_CODE_CLASS (code1))
    {
      int i;
    case '1':
    case '2':
    case '<':
    case 'e':
    case 'r':
    case 's':
      cmp = 1;
      for (i=0; i<tree_code_length[(int) code1]; ++i)
	{
	  cmp = cp_tree_equal (TREE_OPERAND (t1, i), TREE_OPERAND (t2, i));
	  if (cmp <= 0)
	    return cmp;
	}
      return cmp;
    }

  return -1;
}

/* Similar to make_tree_vec, but build on the momentary_obstack.
   Thus, these vectors are really and truly temporary.  */

tree
make_temp_vec (len)
     int len;
{
  register tree node;
  push_expression_obstack ();
  node = make_tree_vec (len);
  pop_obstacks ();
  return node;
}

/* Build a wrapper around some pointer PTR