'ignore-non-existent-contents' stopped working after r342232 in a way
that the actual attribute value isn't used and it works as if it is
always `true`.
Common use case for VFS iteration is iterating through files in umbrella
directories for modules. Ability to detect if some VFS entries point to
non-existing files is nice but non-critical. Instead of adding back
support for `'ignore-non-existent-contents': false` I am removing the
attribute, because such scenario isn't used widely enough and stricter
checks don't provide enough value to justify the maintenance.
rdar://problem/45176119
Reviewers: bruno
Reviewed By: bruno
Subscribers: hiraditya, dexonsmith, sammccall, cfe-commits
Differential Revision: https://reviews.llvm.org/D53228
llvm-svn: 345212
Add 'ignore-non-existent-contents' to tell the VFS whether an invalid path
obtained via 'external-contents' should cause iteration on the VFS to stop.
If 'true', the VFS should ignore the entry and continue with the next. Allows
YAML files to be shared across multiple compiler invocations regardless of
prior existent paths in 'external-contents'. This global value is overridable
on a per-file basis.
This adds the parsing and write test part, but use by VFS comes next.
Differential Revision: https://reviews.llvm.org/D23422
rdar://problem/27531549
llvm-svn: 278456
Volodymyr Sapsai