Periods

A period is a contiguous sequence of phase ids in some run. It is coded as follows:

sign, always 0 1 bit runid 17 bits last phase id: 7 bits #phases before last: 7 bits

// Dmitry: sign == 0 isn't actually always true, in some cases phaseId == -1 is used for shifts, that easily creates code < 0

An ordinal number for phases. First phase has number 1.

An ordinal number for compiler runs. First run has number 1.

Are all base types in the current period guaranteed to be the same as in period p?

The period containing the current period where denotations do not change. We compute this by taking as first phase the first phase less or equal to the current phase that has the same "nextTransformerId". As last phase we take the next transformer id following the current phase.

The number of bits needed to encode a phase identifier.