integer_bit_width records various bit widths for integral types, as used * in relocation calculations. The names are taken directly from the processor * supplements to keep the calculations as close as possible * to the specification of relocations.

natural_of_integer_bit_width i computes the bit width of integer bit width * i.

relocation_operator records the operators used to calculate relocations by * the various ABIs. Each ABI will only use a subset of these, and they should * be interpreted on a per-ABI basis. As more ABIs are added, more operators * will be needed, and therefore more constructors in this type will need to * be added. These are unary operators, operating on a single integral type.

relocation_operator2 is a binary relocation operator, as detailed above.

Some relocations may fail, for example: * Page 58, Power ABI: relocation types whose Field column is marked with an * asterisk are subject to failure is the value computed does not fit in the * allocated bits. can_fail type passes this information back to the caller * of the relocation application function.

relocation_operator_expression is an AST of expressions describing a relocation * calculation. An AST is used as it allows us to unify the treatment of relocation * calculation: rather than passing in dozens of functions to the calculation function * that perform the actual relocation, we can simply return a description (in the form * of the AST below) of the calculation to be carried out and have it interpreted * separately from the function that produces it. The type parameter 'a is the * type of base integral type. This AST suffices for the relocation calculations we * currently have implemented, but adding more ABIs may require that this type is * expanded.