[Windows FS] Allow moving files in TempFile::keep

In r338216 / D49860 TempFile::keep was extended to allow keeping across
filesystems. The aim on Windows was to have this happen in rename_internal
using the existing system API. However, to fix an issue and preserve the
idea of "renaming" not being a move, put Windows keep-across-filesystem in
TempFile::keep.

Differential Revision: https://reviews.llvm.org/D50048

llvm-svn: 338841

llvm/lib/Support/Path.cpp

@@ -1159,8 +1159,16 @@ Error TempFile::keep(const Twine &Name) {
   // If we can't cancel the delete don't rename.
   auto H = reinterpret_cast<HANDLE>(_get_osfhandle(FD));
   std::error_code RenameEC = setDeleteDisposition(H, false);
-  if (!RenameEC)
+  if (!RenameEC) {
     RenameEC = rename_fd(FD, Name);
+    // If rename failed because it's cross-device, copy instead
+    if (RenameEC ==
+      std::error_code(ERROR_NOT_SAME_DEVICE, std::system_category())) {
+      RenameEC = copy_file(TmpName, Name);
+      setDeleteDisposition(H, true);
+    }
+  }
+
   // If we can't rename, discard the temporary file.
   if (RenameEC)
     setDeleteDisposition(H, true);

llvm/lib/Support/Windows/Path.inc

@@ -450,7 +450,7 @@ static std::error_code rename_handle(HANDLE FromHandle, const Twine &To) {
       if (std::error_code EC2 = realPathFromHandle(FromHandle, WideFrom))
         return EC2;
       if (::MoveFileExW(WideFrom.begin(), WideTo.begin(),
-                        MOVEFILE_REPLACE_EXISTING | MOVEFILE_COPY_ALLOWED))
+                        MOVEFILE_REPLACE_EXISTING))
         return std::error_code();
       return mapWindowsError(GetLastError());
     }