Summary:
Add documentation for the LLVM Support functions `openFileForWrite` and
`openFileForRead`. The `openFileForRead` parameter `RealPath`, in
particular, I think warranted some explanation.
In addition, make the behavior of the functions more consistent across
platforms. Prior to this patch, Windows would set or not set the result
file descriptor based on the nature of the error, whereas Unix would
consistently set it to `-1` if the open failed. Make Windows
consistently set it to `-1` as well.
Test Plan:
1. `ninja check-llvm`
2. `ninja docs-llvm-html`
Reviewers: zturner, rnk, danielmartin, scanon
Reviewed By: danielmartin, scanon
Subscribers: scanon, danielmartin, llvm-commits
Differential Revision: https://reviews.llvm.org/D46499
llvm-svn: 332075
82de4e6b93