ValueBlock

A ValueBlock represents a block of data. It is intended mainly for variable initializations.     abstract ValueBlock : ScopedObject
      {
        virtual DataType * reference type;
      };

    concrete ExpressionValueBlock : ValueBlock
      {
        Expression * owner expression in source_ops;
      };

    concrete MultiValueBlock : ValueBlock
      {
        indexed_list<IInteger,ValueBlock * owner> sub_block;
        DataType * reference type;
      };

    concrete RepeatValueBlock : ValueBlock
      {
        int num_repetitions;
        ValueBlock * owner sub_block;
        DataType * reference type;
      };

    concrete UndefinedValueBlock : ValueBlock
      {
        DataType * reference type;
      };

• ValueBlock. There is one common field to all the subclasses of ValueBlock.

  type	Type of the valueblock.

• ExpressionValueBlock. Represents a value that is computed by an expression. Currently restricted to the kinds of computations that traditional linkers can perform and which C allows in static initializations: constants, simple addresses of symbols that are statically allocated, or simple addresses of symbols plus constant integer offsets. The order of evaluation of the static initializers for different variables is not specified, only that the initializations for a given variable are all evaluated before any read from or write to that variable occurs.

  expression

  The expression used for initialization. The result_type of this expression is used as the type of ExpressionValueBlock

• MultiValueBlock. Used to concatenate several smaller value blocks into an agregate, usually to initialize a group or array type. The type is the type of the composite object.

  sub_block

  An indexed list. The index is the bit_offset from the beginning of the ValueBlock. The value of areas between the sub-blocks, if any, is undefined. It is illegal for the sub-blocks to overlap.

• RepeatValueBlock. Similar to a MultiValueBlock, except that instead of combining different ValueBlocks, it repeats one value multiple times in a row to produce a composite value. It is often used inside MultiValueBlocks. The type of this block, though usually irrelevant is that of an array of num_repetitions of the sub_block type.

  num_repetitions	Number of times the ValueBlock is repeated
  sub_block	The ValueBlock to be repeated.

• UndefinedValueBlock. Specifies that the value is completely undefined. The result of any use of an undefined value is undefined.