- Revised handling of volatile reads: the execution environment
  dictates the value read, via the trace of events.


git-svn-id: https://yquem.inria.fr/compcert/svn/compcert/trunk@1345 fca1b0fc-160b-0410-b1d3-a4f43f01ea2e

- Revised memory model with concrete representation of ints & floats,
  and per-byte access permissions
- Revised Globalenvs implementation
- Matching changes in all languages and proofs.


git-svn-id: https://yquem.inria.fr/compcert/svn/compcert/trunk@1282 fca1b0fc-160b-0410-b1d3-a4f43f01ea2e

and reactive divergence.  As a consequence:
- Removed the Enilinf constructor from traceinf (values of traceinf
  type are always infinite traces).
- Traces are now uniquely defined.
- Adapted proofs big step -> small step for Clight and Cminor accordingly.
- Strengthened results in driver/Complements accordingly.
- Added common/Determinism to collect generic results about
  deterministic semantics.


git-svn-id: https://yquem.inria.fr/compcert/svn/compcert/trunk@1123 fca1b0fc-160b-0410-b1d3-a4f43f01ea2e