[PATCH] D41825: [Docs][PDB] Update MSF File documentation

[Colden Cullen via Phabricator via llvm-commits]

colden added a comment.

In https://reviews.llvm.org/D41825#970033, @zturner wrote:

> So each interval has exactly 4096 blocks.  Block 0 is only special in the first interval.  It's still there in every other interval, it just contains regular data.


But according to the code, that can't be true. Specifically, I'm looking at `llvm::msf::getFpmStreamLayout`. If you look at the loop assuming that `FpmBlock` is 1, then it pushes index 1 as the first FPM block, adds the result of `msf::getFpmIntervalLength` (which always returns 4096), and pushes that. This means that the second FPM in the sequence is at index 4097, which would mean that there are 4097 blocks in front of it. Unless block at index 4096 is unused, the first interval is in fact 1 block longer.


Repository:
  rL LLVM

https://reviews.llvm.org/D41825