VFS: Return new file systems as uniquely owned when possible, almost NFC

Uniformly return uniquely-owned filesystems from VFS creation APIs. The
one exception is `getRealFileSystem`, which has a single instance and
needs to be shared.

This is almost NFC, except that it fixes a memory leak in
`vfs::collectVFSFromYAML()`.

Depends on https://reviews.llvm.org/D92888

Differential Revision: https://reviews.llvm.org/D92890

1 files changed, 2 insertions, 2 deletions

diff --git a/llvm/unittests/Support/VirtualFileSystemTest.cpp b/llvm/unittests/Support/VirtualFileSystemTest.cpp
index 4cc209d..1b574b36 100644
--- a/llvm/unittests/Support/VirtualFileSystemTest.cpp
+++ b/llvm/unittests/Support/VirtualFileSystemTest.cpp
@@ -1292,7 +1292,7 @@ public:
     ++Test->NumDiagnostics;
   }
 
-  IntrusiveRefCntPtr<vfs::FileSystem>
+  std::unique_ptr<vfs::FileSystem>
   getFromYAMLRawString(StringRef Content,
                        IntrusiveRefCntPtr<vfs::FileSystem> ExternalFS) {
     std::unique_ptr<MemoryBuffer> Buffer = MemoryBuffer::getMemBuffer(Content);
@@ -1300,7 +1300,7 @@ public:
                           ExternalFS);
   }
 
-  IntrusiveRefCntPtr<vfs::FileSystem> getFromYAMLString(
+  std::unique_ptr<vfs::FileSystem> getFromYAMLString(
       StringRef Content,
       IntrusiveRefCntPtr<vfs::FileSystem> ExternalFS = new DummyFileSystem()) {
     std::string VersionPlusContent("{\n  'version':0,\n");