c-typeck.c

早期freebsd实现

  /* Constants can be used directly unless they're not loadable.  */
  if (TREE_CODE (exp) == CONST_DECL)
    exp = DECL_INITIAL (exp);
  /* Replace a nonvolatile const static variable with its value.  */
  else if (optimize
	   && TREE_CODE (exp) == VAR_DECL
	   && TREE_READONLY (exp)
	   && DECL_MODE (exp) != BLKmode)
    {
      exp = decl_constant_value (exp);
      type = TREE_TYPE (exp);
    }

  /* Strip NON_LVALUE_EXPRs and no-op conversions, since we aren't using as
     an lvalue.  */
  /* Do not use STRIP_NOPS here!  It will remove conversions from pointer
     to integer and cause infinite recursion.  */
  while (TREE_CODE (exp) == NON_LVALUE_EXPR
	 || (TREE_CODE (exp) == NOP_EXPR
	     && TREE_TYPE (TREE_OPERAND (exp, 0)) == TREE_TYPE (exp)))
    exp = TREE_OPERAND (exp, 0);

  /* Normally convert enums to int,
     but convert wide enums to something wider.  */
  if (code == ENUMERAL_TYPE)
    {
      type = type_for_size (MAX (TYPE_PRECISION (type),
				 TYPE_PRECISION (integer_type_node)),
			    (flag_traditional && TREE_UNSIGNED (type)));
      return convert (type, exp);
    }

  if (C_PROMOTING_INTEGER_TYPE_P (type))
    {
      /* Traditionally, unsignedness is preserved in default promotions.
         Also preserve unsignedness if not really getting any wider.  */
      if (TREE_UNSIGNED (type)
	  && (flag_traditional
	      || TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node)))
	return convert (unsigned_type_node, exp);
      return convert (integer_type_node, exp);
    }
  if (flag_traditional && TYPE_MAIN_VARIANT (type) == float_type_node)
    return convert (double_type_node, exp);
  if (code == VOID_TYPE)
    {
      error ("void value not ignored as it ought to be");
      return error_mark_node;
    }
  if (code == FUNCTION_TYPE)
    {
      return build_unary_op (ADDR_EXPR, exp, 0);
    }
  if (code == ARRAY_TYPE)
    {
      register tree adr;
      tree restype = TREE_TYPE (type);
      tree ptrtype;

      if (TREE_CODE (exp) == INDIRECT_REF)
	return convert (TYPE_POINTER_TO (restype),
			TREE_OPERAND (exp, 0));

      if (TREE_CODE (exp) == COMPOUND_EXPR)
	{
	  tree op1 = default_conversion (TREE_OPERAND (exp, 1));
	  return build (COMPOUND_EXPR, TREE_TYPE (op1),
			TREE_OPERAND (exp, 0), op1);
	}

      if (!lvalue_p (exp)
	  && ! (TREE_CODE (exp) == CONSTRUCTOR && TREE_STATIC (exp)))
	{
	  error ("invalid use of non-lvalue array");
	  return error_mark_node;
	}

      if (TYPE_READONLY (type) || TYPE_VOLATILE (type))
	restype = c_build_type_variant (restype, TYPE_READONLY (type),
					TYPE_VOLATILE (type));

      ptrtype = build_pointer_type (restype);

      if (TREE_CODE (exp) == VAR_DECL)
	{
	  /* ??? This is not really quite correct
	     in that the type of the operand of ADDR_EXPR
	     is not the target type of the type of the ADDR_EXPR itself.
	     Question is, can this lossage be avoided?  */
	  adr = build1 (ADDR_EXPR, ptrtype, exp);
	  if (mark_addressable (exp) == 0)
	    return error_mark_node;
	  TREE_CONSTANT (adr) = staticp (exp);
	  TREE_SIDE_EFFECTS (adr) = 0;   /* Default would be, same as EXP.  */
	  return adr;
	}
      /* This way is better for a COMPONENT_REF since it can
	 simplify the offset for a component.  */
      adr = build_unary_op (ADDR_EXPR, exp, 1);
      return convert (ptrtype, adr);
    }
  return exp;
}

/* Make an expression to refer to the COMPONENT field of
   structure or union value DATUM.  COMPONENT is an IDENTIFIER_NODE.  */

tree
build_component_ref (datum, component)
     tree datum, component;
{
  register tree type = TREE_TYPE (datum);
  register enum tree_code code = TREE_CODE (type);
  register tree field = NULL;
  register tree ref;

  /* If DATUM is a COMPOUND_EXPR or COND_EXPR, move our reference inside it
     unless we are not to support things not strictly ANSI.  */
  switch (TREE_CODE (datum))
    {
    case COMPOUND_EXPR:
      {
	tree value = build_component_ref (TREE_OPERAND (datum, 1), component);
	return build (COMPOUND_EXPR, TREE_TYPE (value),
		      TREE_OPERAND (datum, 0), value);
      }
    case COND_EXPR:
      return build_conditional_expr
	(TREE_OPERAND (datum, 0),
	 build_component_ref (TREE_OPERAND (datum, 1), component),
	 build_component_ref (TREE_OPERAND (datum, 2), component));
    }

  /* See if there is a field or component with name COMPONENT.  */

  if (code == RECORD_TYPE || code == UNION_TYPE)
    {
      if (TYPE_SIZE (type) == 0)
	{
	  incomplete_type_error (NULL_TREE, type);
	  return error_mark_node;
	}

      /* Look up component name in the structure type definition.

	 If TYPE_LANG_SPECIFIC is set, then it is a sorted array of pointers
	 to the field elements.  Use a binary search on this array to quickly
	 find the element.  Otherwise, do a linear search.  TYPE_LANG_SPECIFIC
	 will always be set for structures which have many elements.  */

      if (TYPE_LANG_SPECIFIC (type))
	{
	  int bot, top, half;
	  tree *field_array = &TYPE_LANG_SPECIFIC (type)->elts[0];

	  field = TYPE_FIELDS (type);
	  bot = 0;
	  top = TYPE_LANG_SPECIFIC (type)->len;
	  while (top - bot > 1)
	    {
	      int cmp;

	      half = (top - bot + 1) >> 1;
	      field = field_array[bot+half];
	      cmp = (long)DECL_NAME (field) - (long)component;
	      if (cmp == 0)
		break;
	      if (cmp < 0)
		bot += half;
	      else
		top = bot + half;
	    }

	  if (DECL_NAME (field_array[bot]) == component)
	    field = field_array[bot];
	  else if (DECL_NAME (field) != component)
	    field = 0;
	}
      else
	{
	  for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
	    {
	      if (DECL_NAME (field) == component)
		break;
	    }
	}

      if (!field)
	{
	  error (code == RECORD_TYPE
		 ? "structure has no member named `%s'"
		 : "union has no member named `%s'",
		 IDENTIFIER_POINTER (component));
	  return error_mark_node;
	}
      if (TREE_TYPE (field) == error_mark_node)
	return error_mark_node;

      ref = build (COMPONENT_REF, TREE_TYPE (field), datum, field);

      if (TREE_READONLY (datum) || TREE_READONLY (field))
	TREE_READONLY (ref) = 1;
      if (TREE_THIS_VOLATILE (datum) || TREE_THIS_VOLATILE (field))
	TREE_THIS_VOLATILE (ref) = 1;

      return ref;
    }
  else if (code != ERROR_MARK)
    error ("request for member `%s' in something not a structure or union",
	    IDENTIFIER_POINTER (component));

  return error_mark_node;
}

/* Given an expression PTR for a pointer, return an expression
   for the value pointed to.
   ERRORSTRING is the name of the operator to appear in error messages.  */

tree
build_indirect_ref (ptr, errorstring)
     tree ptr;
     char *errorstring;
{
  register tree pointer = default_conversion (ptr);
  register tree type = TREE_TYPE (pointer);

  if (TREE_CODE (type) == POINTER_TYPE)
    if (TREE_CODE (pointer) == ADDR_EXPR
	&& (TREE_TYPE (TREE_OPERAND (pointer, 0))
	    == TREE_TYPE (type)))
      return TREE_OPERAND (pointer, 0);
    else
      {
	tree t = TREE_TYPE (type);
	register tree ref = build1 (INDIRECT_REF,
				    TYPE_MAIN_VARIANT (t), pointer);

	if (TREE_CODE (t) == VOID_TYPE
	    || (TYPE_SIZE (t) == 0 && TREE_CODE (t) != ARRAY_TYPE))
	  {
	    error ("dereferencing pointer to incomplete type");
	    return error_mark_node;
	  }

	/* We *must* set TREE_READONLY when dereferencing a pointer to const,
	   so that we get the proper error message if the result is used
	   to assign to.  Also, &* is supposed to be a no-op.
	   And ANSI C seems to specify that the type of the result
	   should be the const type.  */
	/* A de-reference of a pointer to const is not a const.  It is valid
	   to change it via some other pointer.  */
	TREE_READONLY (ref) = TYPE_READONLY (t);
	TREE_SIDE_EFFECTS (ref) = TYPE_VOLATILE (t) || TREE_SIDE_EFFECTS (pointer);
	TREE_THIS_VOLATILE (ref) = TYPE_VOLATILE (t);
	return ref;
      }
  else if (TREE_CODE (pointer) != ERROR_MARK)
    error ("invalid type argument of `%s'", errorstring);
  return error_mark_node;
}

/* This handles expressions of the form "a[i]", which denotes
   an array reference.

   This is logically equivalent in C to *(a+i), but we may do it differently.
   If A is a variable or a member, we generate a primitive ARRAY_REF.
   This avoids forcing the array out of registers, and can work on
   arrays that are not lvalues (for example, members of structures returned
   by functions).  */

tree
build_array_ref (array, index)
     tree array, index;
{
  if (index == 0)
    {
      error ("subscript missing in array reference");
      return error_mark_node;
    }

  if (TREE_TYPE (array) == error_mark_node
      || TREE_TYPE (index) == error_mark_node)
    return error_mark_node;

  if (TREE_CODE (TREE_TYPE (array)) == ARRAY_TYPE
      && TREE_CODE (array) != INDIRECT_REF)
    {
      tree rval, type;

      /* Subscripting with type char is likely to lose
	 on a machine where chars are signed.
	 So warn on any machine, but optionally.
	 Don't warn for unsigned char since that type is safe.
	 Don't warn for signed char because anyone who uses that
	 must have done so deliberately.  */
      if (warn_char_subscripts
	  && TYPE_MAIN_VARIANT (TREE_TYPE (index)) == char_type_node)
	warning ("array subscript has type `char'");

      /* Apply default promotions *after* noticing character types.  */
      index = default_conversion (index);

      /* Require integer *after* promotion, for sake of enums.  */
      if (TREE_CODE (TREE_TYPE (index)) != INTEGER_TYPE)
	{
	  error ("array subscript is not an integer");
	  return error_mark_node;
	}

      /* An array that is indexed by a non-constant
	 cannot be stored in a register; we must be able to do
	 address arithmetic on its address.
	 Likewise an array of elements of variable size.  */
      if (TREE_CODE (index) != INTEGER_CST
	  || (TYPE_SIZE (TREE_TYPE (TREE_TYPE (array))) != 0
	      && TREE_CODE (TYPE_SIZE (TREE_TYPE (TREE_TYPE (array)))) != INTEGER_CST))
	{
	  if (mark_addressable (array) == 0)
	    return error_mark_node;
	}

      if (pedantic && !lvalue_p (array))
	{
	  if (DECL_REGISTER (array))
	    pedwarn ("ANSI C forbids subscripting `register' array");
	  else
	    pedwarn ("ANSI C forbids subscripting non-lvalue array");
	}

      if (pedantic)
	{
	  tree foo = array;
	  while (TREE_CODE (foo) == COMPONENT_REF)
	    foo = TREE_OPERAND (foo, 0);
	  if (TREE_CODE (foo) == VAR_DECL && DECL_REGISTER (foo))
	    pedwarn ("ANSI C forbids subscripting non-lvalue array");
	}

      type = TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (array)));
      rval = build (ARRAY_REF, type, array, index);
      /* Array ref is const/volatile if the array elements are
         or if the array is.  */
      TREE_READONLY (rval)
	|= (TYPE_READONLY (TREE_TYPE (TREE_TYPE (array)))
	    | TREE_READONLY (array));
      TREE_SIDE_EFFECTS (rval)
	|= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
	    | TREE_SIDE_EFFECTS (array));
      TREE_THIS_VOLATILE (rval)
	|= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
	    /* This was added by rms on 16 Nov 91.
	       It fixes  vol struct foo *a;  a->elts[1] 
	       in an inline function.
	       Hope it doesn't break something else.  */
	    | TREE_THIS_VOLATILE (array));
      return require_complete_type (fold (rval));
    }

  {
    tree ar = default_conversion (array);
    tree ind = default_conversion (index);

    /* Put the integer in IND to simplify error checking.  */
    if (TREE_CODE (TREE_TYPE (ar)) == INTEGER_TYPE)
      {
	tree temp = ar;
	ar = ind;
	ind = temp;
      }

    if (ar == error_mark_node)
      return ar;

    if (TREE_CODE (TREE_TYPE (ar)) != POINTER_TYPE)
      {
	error ("subscripted value is neither array nor pointer");
	return error_mark_node;
      }
    if (TREE_CODE (TREE_TYPE (ind)) != INTEGER_TYPE)
      {
	error ("array subscript is not an integer");
	return error_mark_node;
      }

    return build_indirect_ref (build_binary_op (PLUS_EXPR, ar, ind, 0),
			       "array indexing");
  }
}

/* Check a printf/fprintf/sprintf/scanf/fscanf/sscanf format against PARAMS.  */

#define ISDIGIT(c)	((c) >= '0' && (c) <= '9')

#define T_I	&integer_type_node
#define T_L	&long_integer_type_node
#define T_S	&short_integer_type_node
#define T_UI	&unsigned_type_node
#define T_UL	&long_unsigned_type_node
#define T_US	&short_unsigned_type_node
#define T_F	&float_type_node
#define T_D	&double_type_node
#define T_LD	&long_double_type_node
#define T_C	&char_type_node
#define T_V	&void_type_node
#define T_W	&wchar_type_node

typedef struct
{
  char *format_chars;
  int pointer_count;
  /* Type of argument if no length modifier is used.  */
  tree *nolen;
  /* Type of argument if length modifier for shortening is used.
     If NULL, then this modifier is not allowed.  */
  tree *hlen;
  /* Type of argument if length modifier `l' is used.
     If NULL, then this modifier is not allowed.  */
  tree *llen;
  /* Type of argument if length modifier `L' is used.
     If NULL, then this modifier is not allowed.  */
  tree *bigllen;
  /* List of other modifier characters allowed with these options.  */
  char *flag_chars;
} format_char_info;

static format_char_info print_table[]
  = {
      { "di",		0,	T_I,	T_I,	T_L,	NULL,	"-wp0 +" },
      { "oxX",		0,	T_UI,	T_UI,	T_UL,	NULL,	"-wp0#" },
      { "u",		0,	T_UI,	T_UI,	T_UL,	NULL,	"-wp0" },
      { "feEgG",	0,	T_D,	NULL,	NULL,	T_LD,	"-wp0 +#" },
      { "c",		0,	T_I,	NULL,	T_W,	NULL,	"-w" },
      { "C",		0,	T_W,	NULL,	NULL,	NULL,	"-w" },
      { "s",		1,	T_C,	NULL,	T_W,	NULL,	"-wp" },