c-typeck.c

早期freebsd实现

      }

    case RECORD_TYPE:
      return maybe_objc_comptypes (t1, t2);
    }
  return 0;
}

/* Return 1 if TTL and TTR are pointers to types that are equivalent,
   ignoring their qualifiers.  */

static int
comp_target_types (ttl, ttr)
     tree ttl, ttr;
{
  int val = comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (ttl)),
		       TYPE_MAIN_VARIANT (TREE_TYPE (ttr)));
  if (val == 2 && pedantic)
    pedwarn ("types are not quite compatible");
  return val;
}

/* Subroutines of `comptypes'.  */

/* Return 1 if two function types F1 and F2 are compatible.
   If either type specifies no argument types,
   the other must specify a fixed number of self-promoting arg types.
   Otherwise, if one type specifies only the number of arguments, 
   the other must specify that number of self-promoting arg types.
   Otherwise, the argument types must match.  */

static int
function_types_compatible_p (f1, f2)
     tree f1, f2;
{
  tree args1, args2;
  /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
  int val = 1;
  int val1;

  if (!(TREE_TYPE (f1) == TREE_TYPE (f2)
	|| (val = comptypes (TREE_TYPE (f1), TREE_TYPE (f2)))))
    return 0;

  args1 = TYPE_ARG_TYPES (f1);
  args2 = TYPE_ARG_TYPES (f2);

  /* An unspecified parmlist matches any specified parmlist
     whose argument types don't need default promotions.  */

  if (args1 == 0)
    {
      if (!self_promoting_args_p (args2))
	return 0;
      /* If one of these types comes from a non-prototype fn definition,
	 compare that with the other type's arglist.
	 If they don't match, ask for a warning (but no error).  */
      if (TYPE_ACTUAL_ARG_TYPES (f1)
	  && 1 != type_lists_compatible_p (args2, TYPE_ACTUAL_ARG_TYPES (f1)))
	val = 2;
      return val;
    }
  if (args2 == 0)
    {
      if (!self_promoting_args_p (args1))
	return 0;
      if (TYPE_ACTUAL_ARG_TYPES (f2)
	  && 1 != type_lists_compatible_p (args1, TYPE_ACTUAL_ARG_TYPES (f2)))
	val = 2;
      return val;
    }

  /* Both types have argument lists: compare them and propagate results.  */
  val1 = type_lists_compatible_p (args1, args2);
  return val1 != 1 ? val1 : val;
}

/* Check two lists of types for compatibility,
   returning 0 for incompatible, 1 for compatible,
   or 2 for compatible with warning.  */

static int
type_lists_compatible_p (args1, args2)
     tree args1, args2;
{
  /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
  int val = 1;
  int newval;

  while (1)
    {
      if (args1 == 0 && args2 == 0)
	return val;
      /* If one list is shorter than the other,
	 they fail to match.  */
      if (args1 == 0 || args2 == 0)
	return 0;
      /* A null pointer instead of a type
	 means there is supposed to be an argument
	 but nothing is specified about what type it has.
	 So match anything that self-promotes.  */
      if (TREE_VALUE (args1) == 0)
	{
	  if (! self_promoting_type_p (TREE_VALUE (args2)))
	    return 0;
	}
      else if (TREE_VALUE (args2) == 0)
	{
	  if (! self_promoting_type_p (TREE_VALUE (args1)))
	    return 0;
	}
      else if (! (newval = comptypes (TREE_VALUE (args1), TREE_VALUE (args2))))
	{
	  /* Allow  wait (union {union wait *u; int *i} *)
	     and  wait (union wait *)  to be compatible.  */
	  if (TREE_CODE (TREE_VALUE (args1)) == UNION_TYPE
	      && TYPE_NAME (TREE_VALUE (args1)) == 0
	      && TREE_CODE (TYPE_SIZE (TREE_VALUE (args1))) == INTEGER_CST
	      && tree_int_cst_equal (TYPE_SIZE (TREE_VALUE (args1)),
				     TYPE_SIZE (TREE_VALUE (args2))))
	    {
	      tree memb;
	      for (memb = TYPE_FIELDS (TREE_VALUE (args1));
		   memb; memb = TREE_CHAIN (memb))
		if (comptypes (TREE_TYPE (memb), TREE_VALUE (args2)))
		  break;
	      if (memb == 0)
		return 0;
	    }
	  else if (TREE_CODE (TREE_VALUE (args2)) == UNION_TYPE
		   && TYPE_NAME (TREE_VALUE (args2)) == 0
		   && TREE_CODE (TYPE_SIZE (TREE_VALUE (args2))) == INTEGER_CST
		   && tree_int_cst_equal (TYPE_SIZE (TREE_VALUE (args2)),
					  TYPE_SIZE (TREE_VALUE (args1))))
	    {
	      tree memb;
	      for (memb = TYPE_FIELDS (TREE_VALUE (args2));
		   memb; memb = TREE_CHAIN (memb))
		if (comptypes (TREE_TYPE (memb), TREE_VALUE (args1)))
		  break;
	      if (memb == 0)
		return 0;
	    }
	  else
	    return 0;
	}

      /* comptypes said ok, but record if it said to warn.  */
      if (newval > val)
	val = newval;

      args1 = TREE_CHAIN (args1);
      args2 = TREE_CHAIN (args2);
    }
}

/* Return 1 if PARMS specifies a fixed number of parameters
   and none of their types is affected by default promotions.  */

int
self_promoting_args_p (parms)
     tree parms;
{
  register tree t;
  for (t = parms; t; t = TREE_CHAIN (t))
    {
      register tree type = TREE_VALUE (t);

      if (TREE_CHAIN (t) == 0 && type != void_type_node)
	return 0;

      if (type == 0)
	return 0;

      if (TYPE_MAIN_VARIANT (type) == float_type_node)
	return 0;

      if (C_PROMOTING_INTEGER_TYPE_P (type))
	return 0;
    }
  return 1;
}

/* Return 1 if TYPE is not affected by default promotions.  */

static int
self_promoting_type_p (type)
     tree type;
{
  if (TYPE_MAIN_VARIANT (type) == float_type_node)
    return 0;

  if (C_PROMOTING_INTEGER_TYPE_P (type))
    return 0;

  return 1;
}

/* Return an unsigned type the same as TYPE in other respects.  */

tree
unsigned_type (type)
     tree type;
{
  tree type1 = TYPE_MAIN_VARIANT (type);
  if (type1 == signed_char_type_node || type1 == char_type_node)
    return unsigned_char_type_node;
  if (type1 == integer_type_node)
    return unsigned_type_node;
  if (type1 == short_integer_type_node)
    return short_unsigned_type_node;
  if (type1 == long_integer_type_node)
    return long_unsigned_type_node;
  if (type1 == long_long_integer_type_node)
    return long_long_unsigned_type_node;
  return type;
}

/* Return a signed type the same as TYPE in other respects.  */

tree
signed_type (type)
     tree type;
{
  tree type1 = TYPE_MAIN_VARIANT (type);
  if (type1 == unsigned_char_type_node || type1 == char_type_node)
    return signed_char_type_node;
  if (type1 == unsigned_type_node)
    return integer_type_node;
  if (type1 == short_unsigned_type_node)
    return short_integer_type_node;
  if (type1 == long_unsigned_type_node)
    return long_integer_type_node;
  if (type1 == long_long_unsigned_type_node)
    return long_long_integer_type_node;
  return type;
}

/* Return a type the same as TYPE except unsigned or
   signed according to UNSIGNEDP.  */

tree
signed_or_unsigned_type (unsignedp, type)
     int unsignedp;
     tree type;
{
  if (TREE_CODE (type) != INTEGER_TYPE)
    return type;
  if (TYPE_PRECISION (type) == TYPE_PRECISION (signed_char_type_node))
    return unsignedp ? unsigned_char_type_node : signed_char_type_node;
  if (TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node)) 
    return unsignedp ? unsigned_type_node : integer_type_node;
  if (TYPE_PRECISION (type) == TYPE_PRECISION (short_integer_type_node)) 
    return unsignedp ? short_unsigned_type_node : short_integer_type_node;
  if (TYPE_PRECISION (type) == TYPE_PRECISION (long_integer_type_node)) 
    return unsignedp ? long_unsigned_type_node : long_integer_type_node;
  if (TYPE_PRECISION (type) == TYPE_PRECISION (long_long_integer_type_node)) 
    return (unsignedp ? long_long_unsigned_type_node
	    : long_long_integer_type_node);
  return type;
}

/* Compute the value of the `sizeof' operator.  */

tree
c_sizeof (type)
     tree type;
{
  enum tree_code code = TREE_CODE (type);

  if (code == FUNCTION_TYPE)
    {
      if (pedantic || warn_pointer_arith)
	pedwarn ("sizeof applied to a function type");
      return size_int (1);
    }
  if (code == VOID_TYPE)
    {
      if (pedantic || warn_pointer_arith)
	pedwarn ("sizeof applied to a void type");
      return size_int (1);
    }
  if (code == ERROR_MARK)
    return size_int (1);
  if (TYPE_SIZE (type) == 0)
    {
      error ("sizeof applied to an incomplete type");
      return size_int (0);
    }

  /* Convert in case a char is more than one unit.  */
  return size_binop (CEIL_DIV_EXPR, TYPE_SIZE (type), 
		     size_int (TYPE_PRECISION (char_type_node)));
}

tree
c_sizeof_nowarn (type)
     tree type;
{
  enum tree_code code = TREE_CODE (type);

  if (code == FUNCTION_TYPE
      || code == VOID_TYPE
      || code == ERROR_MARK)
    return size_int (1);
  if (TYPE_SIZE (type) == 0)
    return size_int (0);

  /* Convert in case a char is more than one unit.  */
  return size_binop (CEIL_DIV_EXPR, TYPE_SIZE (type), 
		     size_int (TYPE_PRECISION (char_type_node)));
}

/* Compute the size to increment a pointer by.  */

tree
c_size_in_bytes (type)
     tree type;
{
  enum tree_code code = TREE_CODE (type);

  if (code == FUNCTION_TYPE)
    return size_int (1);
  if (code == VOID_TYPE)
    return size_int (1);
  if (code == ERROR_MARK)
    return size_int (1);
  if (TYPE_SIZE (type) == 0)
    {
      error ("arithmetic on pointer to an incomplete type");
      return size_int (1);
    }

  /* Convert in case a char is more than one unit.  */
  return size_binop (CEIL_DIV_EXPR, TYPE_SIZE (type), 
		     size_int (BITS_PER_UNIT));
}

/* Implement the __alignof keyword: Return the minimum required
   alignment of TYPE, measured in bytes.  */

tree
c_alignof (type)
     tree type;
{
  enum tree_code code = TREE_CODE (type);

  if (code == FUNCTION_TYPE)
    return size_int (FUNCTION_BOUNDARY / BITS_PER_UNIT);

  if (code == VOID_TYPE || code == ERROR_MARK)
    return size_int (1);

  return size_int (TYPE_ALIGN (type) / BITS_PER_UNIT);
}

/* Implement the __alignof keyword: Return the minimum required
   alignment of EXPR, measured in bytes.  For VAR_DECL's and
   FIELD_DECL's return DECL_ALIGN (which can be set from an
   "aligned" __attribute__ specification).  */

tree
c_alignof_expr (expr)
     tree expr;
{
  if (TREE_CODE (expr) == VAR_DECL)
    return size_int (DECL_ALIGN (expr) / BITS_PER_UNIT);
 
  if (TREE_CODE (expr) == COMPONENT_REF
      && DECL_BIT_FIELD (TREE_OPERAND (expr, 1)))
    {
      error ("`__alignof' applied to a bit-field");
      return size_int (1);
    }
  else if (TREE_CODE (expr) == COMPONENT_REF
      && TREE_CODE (TREE_OPERAND (expr, 1)) == FIELD_DECL)
    return size_int (DECL_ALIGN (TREE_OPERAND (expr, 1)) / BITS_PER_UNIT);
 
  if (TREE_CODE (expr) == INDIRECT_REF)
    {
      tree t = TREE_OPERAND (expr, 0);
      tree best = t;
      int bestalign = TYPE_ALIGN (TREE_TYPE (TREE_TYPE (t)));
 
      while (TREE_CODE (t) == NOP_EXPR
	      && TREE_CODE (TREE_TYPE (TREE_OPERAND (t, 0))) == POINTER_TYPE)
	{
	  int thisalign;

	  t = TREE_OPERAND (t, 0);
	  thisalign = TYPE_ALIGN (TREE_TYPE (TREE_TYPE (t)));
	  if (thisalign > bestalign)
	    best = t, bestalign = thisalign;
	}
      return c_alignof (TREE_TYPE (TREE_TYPE (best)));
    }
  else
    return c_alignof (TREE_TYPE (expr));
}
/* Return either DECL or its known constant value (if it has one).  */

static tree
decl_constant_value (decl)
     tree decl;
{
  if (! TREE_PUBLIC (decl)
      /* Don't change a variable array bound or initial value to a constant
	 in a place where a variable is invalid.  */
      && current_function_decl != 0
      && ! pedantic
      && ! TREE_THIS_VOLATILE (decl)
      && DECL_INITIAL (decl) != 0
      && TREE_CODE (DECL_INITIAL (decl)) != ERROR_MARK
      /* This is invalid if initial value is not constant.
	 If it has either a function call, a memory reference,
	 or a variable, then re-evaluating it could give different results.  */
      && TREE_CONSTANT (DECL_INITIAL (decl))
      /* Check for cases where this is sub-optimal, even though valid.  */
      && TREE_CODE (DECL_INITIAL (decl)) != CONSTRUCTOR
      && DECL_MODE (decl) != BLKmode)
    return DECL_INITIAL (decl);
  return decl;
}

/* Perform default promotions for C data used in expressions.
   Arrays and functions are converted to pointers;
   enumeral types or short or char, to int.
   In addition, manifest constants symbols are replaced by their values.  */

tree
default_conversion (exp)
     tree exp;
{
  register tree type = TREE_TYPE (exp);
  register enum tree_code code = TREE_CODE (type);