[VFS] Remove 'ignore-non-existent-contents' attribute for YAML-based VFS.

'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

1 files changed, 0 insertions, 4 deletions

diff --git a/clang/lib/Frontend/ModuleDependencyCollector.cpp b/clang/lib/Frontend/ModuleDependencyCollector.cpp
index 25cad8be6d0..fa8efcc3b53 100644
--- a/clang/lib/Frontend/ModuleDependencyCollector.cpp
+++ b/clang/lib/Frontend/ModuleDependencyCollector.cpp
@@ -156,10 +156,6 @@ void ModuleDependencyCollector::writeFileMap() {
   // allows crash reproducer scripts to work across machines.
   VFSWriter.setOverlayDir(VFSDir);
 
-  // Do not ignore non existent contents otherwise we might skip something
-  // that should have been collected here.
-  VFSWriter.setIgnoreNonExistentContents(false);
-
   // Explicitly set case sensitivity for the YAML writer. For that, find out
   // the sensitivity at the path where the headers all collected to.
   VFSWriter.setCaseSensitivity(isCaseSensitivePath(VFSDir));