[PATCH] D54995: [MemoryBuffer] By default assume that all files are volatile to prevent unintended file locks

[Ilya Biryukov via Phabricator via cfe-commits]

ilya-biryukov added a comment.

In D54995#1311010 <https://reviews.llvm.org/D54995#1311010>, @yvvan wrote:

> @ilya-biryukov
>
> I have the reported evidence but didn't yet have time to investigate myself.
>  This is probably caused by our upgrade to Clang-7 which shows that we can't rely on the aimed fixes like the one I mention (D47460 <https://reviews.llvm.org/D47460>).
>
> Another option that I can suggest here is to remove all default isVolatile values at all, track all callers and specify the proper value in each case (ideally depending on the current flags). What do you think?


Before we start changing all the callers or the defaults, it would be nice to know we don't have other options. The reason I'm begging for a repro is to understand what's going and make sure we can't fix it on the lower levels.
If we want to switch everyone to use non-memory-mapped files by default, we better have a very good reason to do so and know about the trade-offs.

My hope is that we can get rid of this flag some day rather than put it into more places or change a default to something that seems less efficient (I don't have data, so that's an uninformed opinion).


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D54995/new/

https://reviews.llvm.org/D54995