[sanitizer] Size class map & local cache improvements

Summary:
- Reland rL324263, this time allowing for a compile-time decision as to whether
  or not use the 32-bit division. A single test is using a class map covering
  a maximum size greater than 4GB, this can be checked via the template
  parameters, and allows SizeClassAllocator64PopulateFreeListOOM to pass;
- `MaxCachedHint` is always called on a class id for which we have already
  computed the size, but we still recompute `Size(class_id)`. Change the
  prototype of the function to work on sizes instead of class ids. This also
  allows us to get rid of the `kBatchClassID` special case. Update the callers
  accordingly;
- `InitCache` and `Drain` will start iterating at index 1: index 0 contents are
  unused and can safely be left to be 0. Plus we do not pay the cost of going
  through an `UNLIKELY` in `MaxCachedHint`, and touching memory that is
  otherwise not used;
- `const` some variables in the areas modified;
- Remove an spurious extra line at the end of a file.

Reviewers: alekseyshl, tl0gic, dberris

Reviewed By: alekseyshl, dberris

Subscribers: dberris, kubamracek, delcypher, llvm-commits, #sanitizers

Differential Revision: https://reviews.llvm.org/D43088

llvm-svn: 324906

0 files changed, 0 insertions, 0 deletions