Don't fallback to copy + delete in rename.

Rename's documentation says "Files are renamed as if by POSIX rename()". and it
is used for atomically updating output files from a temporary. Having rename
fallback to a non atomic copy has the potential to hide bugs, like using
a temporary file in /tmp instead of a unique name next to the final destination.

llvm-svn: 186483

diff --git a/llvm/lib/Support/Unix/Path.inc b/llvm/lib/Support/Unix/Path.inc
index 9795b6e..0c1623a 100644 (file)
--- a/llvm/lib/Support/Unix/Path.inc
+++ b/llvm/lib/Support/Unix/Path.inc
@@ -456,17 +456,8 @@ error_code rename(const Twine &from, const Twine &to) {
   StringRef f = from.toNullTerminatedStringRef(from_storage);
   StringRef t = to.toNullTerminatedStringRef(to_storage);
 
-  if (::rename(f.begin(), t.begin()) == -1) {
-    // If it's a cross device link, copy then delete, otherwise return the error
-    if (errno == EXDEV) {
-      if (error_code ec = copy_file(from, to, copy_option::overwrite_if_exists))
-        return ec;
-      bool Existed;
-      if (error_code ec = remove(from, Existed))
-        return ec;
-    } else
-      return error_code(errno, system_category());
-  }
+  if (::rename(f.begin(), t.begin()) == -1)
+    return error_code(errno, system_category());
 
   return error_code::success();
 }