Index: llvm/include/llvm/Support/FileSystem.h
===================================================================
--- llvm/include/llvm/Support/FileSystem.h
+++ llvm/include/llvm/Support/FileSystem.h
@@ -716,7 +716,11 @@
   OF_Append = 2,
   F_Append = 2, // For compatibility
 
-  /// Delete the file on close. Only makes a difference on windows.
+  /// Delete the file on close.  This is guaranteed to be supported on all
+  /// platforms, and it is guaranteed that the file descriptor / file object
+  /// that is returned from the open call is valid and usable in the way the
+  /// user has requested.  However, it is **not** guaranteed that
+  /// exists(Path) will return true after the call to open returns.
   OF_Delete = 4
 };
 
Index: llvm/lib/Support/Unix/Path.inc
===================================================================
--- llvm/lib/Support/Unix/Path.inc
+++ llvm/lib/Support/Unix/Path.inc
@@ -774,6 +774,9 @@
   (void)r;
   assert(r == 0 && "fcntl(F_SETFD, FD_CLOEXEC) failed");
 #endif
+  if (Flags & OF_Delete)
+    ::unlink(P.data());
+
   return std::error_code();
 }
 
Index: llvm/unittests/Support/Path.cpp
===================================================================
--- llvm/unittests/Support/Path.cpp
+++ llvm/unittests/Support/Path.cpp
@@ -1458,6 +1458,26 @@
   verifyWrite(FD, "Buzz", true);
 }
 
+TEST_F(FileSystemTest, DeleteOnClose) {
+  createFileWithData(NonExistantFile, false, fs::CD_CreateNew, "Fizz");
+
+  // Even though we expect the file to be deleted automatically on close, we put
+  // this here as a failsafe so it gets removed even if the test fails, so we
+  // don't clutter up a file system.
+  FileRemover Cleanup(NonExistantFile);
+
+  int FD;
+  Optional<FileDescriptorCloser> Closer;
+
+  ASSERT_NO_ERROR(fs::openFileForReadWrite(NonExistantFile, FD,
+                                           fs::CD_OpenExisting, fs::OF_Delete));
+  Closer.emplace(FD);
+  verifyRead(FD, "Fizz", true);
+  verifyWrite(FD, "Buzz", true);
+  Closer.reset();
+  ASSERT_FALSE(fs::exists(NonExistantFile));
+}
+
 TEST_F(FileSystemTest, set_current_path) {
   SmallString<128> path;