gcc-func.c

使用yacc和lex编写的cmm语言的词法分析和语法分析程序.

    case NEGATE_EXPR:
      if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE))
        errstring = "wrong type argument to unary minus";
      else if (!noconvert)
	arg = default_conversion (arg);
      break;

    case BIT_NOT_EXPR:
      if (typecode != INTEGER_TYPE)
        errstring = "wrong type argument to bit-complement";
      else if (!noconvert)
	arg = default_conversion (arg);
      break;

    case ABS_EXPR:
      if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE))
        errstring = "wrong type argument to abs";
      else if (!noconvert)
	arg = default_conversion (arg);
      break;

    case TRUTH_NOT_EXPR:
      if (typecode != INTEGER_TYPE
	  && typecode != REAL_TYPE && typecode != POINTER_TYPE
	  /* These will convert to a pointer.  */
	  && typecode != ARRAY_TYPE && typecode != FUNCTION_TYPE)
	{
	  errstring = "wrong type argument to unary exclamation mark";
	  break;
	}
      arg = truthvalue_conversion (arg);
      return invert_truthvalue (arg);

    case NOP_EXPR:
      break;
      
    case PREINCREMENT_EXPR:
    case POSTINCREMENT_EXPR:
    case PREDECREMENT_EXPR:
    case POSTDECREMENT_EXPR:
      /* Handle complex lvalues (when permitted)
	 by reduction to simpler cases.  */

      val = unary_complex_lvalue (code, arg);
      if (val != 0)
	return val;

      /* Report invalid types.  */

      if (typecode != POINTER_TYPE
	  && typecode != INTEGER_TYPE && typecode != REAL_TYPE)
	{
	  if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
	    errstring ="wrong type argument to increment";
	  else
	    errstring ="wrong type argument to decrement";
	  break;
	}

      {
	register tree inc;
	tree result_type = TREE_TYPE (arg);

	arg = get_unwidened (arg, 0);
	argtype = TREE_TYPE (arg);

	/* Compute the increment.  */

	if (typecode == POINTER_TYPE)
	  {
	    if (pedantic
		&& (TREE_CODE (TREE_TYPE (result_type)) == FUNCTION_TYPE
		    || TREE_CODE (TREE_TYPE (result_type)) == VOID_TYPE))
	      pedwarn ("wrong type argument to %s",
		       ((code == PREINCREMENT_EXPR
			 || code == POSTINCREMENT_EXPR)
			? "increment" : "decrement"));
	    inc = c_sizeof_nowarn (TREE_TYPE (result_type));
	  }
	else
	  inc = integer_one_node;

	inc = convert (argtype, inc);

	/* Handle incrementing a cast-expression.  */

	while (1)
	  switch (TREE_CODE (arg))
	    {
	    case NOP_EXPR:
	    case CONVERT_EXPR:
	    case FLOAT_EXPR:
	    case FIX_TRUNC_EXPR:
	    case FIX_FLOOR_EXPR:
	    case FIX_ROUND_EXPR:
	    case FIX_CEIL_EXPR:
	      /* If the real type has the same machine representation
		 as the type it is cast to, we can make better output
		 by adding directly to the inside of the cast.  */
	      if ((TREE_CODE (TREE_TYPE (arg))
		   == TREE_CODE (TREE_TYPE (TREE_OPERAND (arg, 0))))
		  && (TYPE_MODE (TREE_TYPE (arg))
		      == TYPE_MODE (TREE_TYPE (TREE_OPERAND (arg, 0)))))
		arg = TREE_OPERAND (arg, 0);
	      else
		{
		  tree incremented, modify, value;
		  pedantic_lvalue_warning (CONVERT_EXPR);
		  arg = stabilize_reference (arg);
		  if (code == PREINCREMENT_EXPR || code == PREDECREMENT_EXPR)
		    value = arg;
		  else
		    value = save_expr (arg);
		  incremented = build (((code == PREINCREMENT_EXPR
					 || code == POSTINCREMENT_EXPR)
					? PLUS_EXPR : MINUS_EXPR),
				       argtype, value, inc);
		  TREE_SIDE_EFFECTS (incremented) = 1;
		  modify = build_modify_expr (arg, NOP_EXPR, incremented);
		  value = build (COMPOUND_EXPR, TREE_TYPE (arg), modify, value);
		  TREE_USED (value) = 1;
		  return value;
		}
	      break;

	    default:
	      goto give_up;
	    }
      give_up:

	/* Complain about anything else that is not a true lvalue.  */
	if (!lvalue_or_else (arg, ((code == PREINCREMENT_EXPR
				    || code == POSTINCREMENT_EXPR)
				   ? "increment" : "decrement")))
	  return error_mark_node;

	/* Report a read-only lvalue.  */
	if (TYPE_READONLY (TREE_TYPE (arg)))
	  readonly_warning (arg, 
			    ((code == PREINCREMENT_EXPR
			      || code == POSTINCREMENT_EXPR)
			     ? "increment" : "decrement"));

	val = build (code, TREE_TYPE (arg), arg, inc);
	TREE_SIDE_EFFECTS (val) = 1;
	val = convert (result_type, val);
	if (TREE_CODE (val) != code)
	  TREE_NO_UNUSED_WARNING (val) = 1;
	return val;
      }

    case ADDR_EXPR:
      /* Note that this operation never does default_conversion
	 regardless of NOCONVERT.  */

      /* Let &* cancel out to simplify resulting code.  */
      if (TREE_CODE (arg) == INDIRECT_REF)
	{
	  /* Don't let this be an lvalue.  */
	  if (lvalue_p (TREE_OPERAND (arg, 0)))
	    return non_lvalue (TREE_OPERAND (arg, 0));
	  return TREE_OPERAND (arg, 0);
	}

      /* For &x[y], return x+y */
      if (TREE_CODE (arg) == ARRAY_REF)
	{
	  if (mark_addressable (TREE_OPERAND (arg, 0)) == 0)
	    return error_mark_node;
	  return build_binary_op (PLUS_EXPR, TREE_OPERAND (arg, 0),
				  TREE_OPERAND (arg, 1), 1);
	}

      /* Handle complex lvalues (when permitted)
	 by reduction to simpler cases.  */
      val = unary_complex_lvalue (code, arg);
      if (val != 0)
	return val;

#if 0 /* Turned off because inconsistent;
	 float f; *&(int)f = 3.4 stores in int format
	 whereas (int)f = 3.4 stores in float format.  */
      /* Address of a cast is just a cast of the address
	 of the operand of the cast.  */
      switch (TREE_CODE (arg))
	{
	case NOP_EXPR:
	case CONVERT_EXPR:
	case FLOAT_EXPR:
	case FIX_TRUNC_EXPR:
	case FIX_FLOOR_EXPR:
	case FIX_ROUND_EXPR:
	case FIX_CEIL_EXPR:
	  if (pedantic)
	    pedwarn ("ANSI C forbids the address of a cast expression");
	  return convert (build_pointer_type (TREE_TYPE (arg)),
			  build_unary_op (ADDR_EXPR, TREE_OPERAND (arg, 0),
					  0));
	}
#endif

      /* Allow the address of a constructor if all the elements
	 are constant.  */
      if (TREE_CODE (arg) == CONSTRUCTOR && TREE_CONSTANT (arg))
	;
      /* Anything not already handled and not a true memory reference
	 is an error.  */
      else if (typecode != FUNCTION_TYPE && !lvalue_or_else (arg, "unary `&'"))
	return error_mark_node;

      /* Ordinary case; arg is a COMPONENT_REF or a decl.  */
      argtype = TREE_TYPE (arg);
      /* If the lvalue is const or volatile,
	 merge that into the type that the address will point to.  */
      if (TREE_CODE_CLASS (TREE_CODE (arg)) == 'd'
	  || TREE_CODE_CLASS (TREE_CODE (arg)) == 'r')
	{
	  if (TREE_READONLY (arg) || TREE_THIS_VOLATILE (arg))
	    argtype = c_build_type_variant (argtype,
					    TREE_READONLY (arg),
					    TREE_THIS_VOLATILE (arg));
	}

      argtype = build_pointer_type (argtype);

      if (mark_addressable (arg) == 0)
	return error_mark_node;

      {
	tree addr;

	if (TREE_CODE (arg) == COMPONENT_REF)
	  {
	    tree field = TREE_OPERAND (arg, 1);

	    addr = build_unary_op (ADDR_EXPR, TREE_OPERAND (arg, 0), 0);

	    if (DECL_BIT_FIELD (field))
	      {
		error ("attempt to take address of bit-field structure member `%s'",
		       IDENTIFIER_POINTER (DECL_NAME (field)));
		return error_mark_node;
	      }

	    addr = convert (argtype, addr);

	    if (! integer_zerop (DECL_FIELD_BITPOS (field)))
	      {
		tree offset
		  = size_binop (EASY_DIV_EXPR, DECL_FIELD_BITPOS (field),
				size_int (BITS_PER_UNIT));
		int flag = TREE_CONSTANT (addr);
		addr = fold (build (PLUS_EXPR, argtype,
				    addr, convert (argtype, offset)));
		TREE_CONSTANT (addr) = flag;
	      }
	  }
	else
	  addr = build1 (code, argtype, arg);

	/* Address of a static or external variable or
	   function counts as a constant */
	TREE_CONSTANT (addr) = staticp (arg);
	return addr;
      }
    }

  if (!errstring)
    {
      if (argtype == 0)
	argtype = TREE_TYPE (arg);
      return fold (build1 (code, argtype, arg));
    }

  error (errstring);
  return error_mark_node;
}