From f087ddcbc459f92e49941eca67b3eeb7e7340b55 Mon Sep 17 00:00:00 2001
From: Rafael Espindola <rafael.espindola@gmail.com>
Date: Mon, 13 Apr 2015 11:09:48 +0000
Subject: [PATCH] Fix SupportsSeeking detection on windows.

Will be tested by existing tests once used (soon).

llvm-svn: 234737
---
 lib/Support/raw_ostream.cpp | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/lib/Support/raw_ostream.cpp b/lib/Support/raw_ostream.cpp
index b8588af702b..16c52c90e09 100644
--- a/lib/Support/raw_ostream.cpp
+++ b/lib/Support/raw_ostream.cpp
@@ -525,7 +525,14 @@ raw_fd_ostream::raw_fd_ostream(int fd, bool shouldClose, bool unbuffered)
 
   // Get the starting position.
   off_t loc = ::lseek(FD, 0, SEEK_CUR);
+#ifdef LLVM_ON_WIN32
+  // MSVCRT's _lseek(SEEK_CUR) doesn't return -1 for pipes.
+  sys::fs::file_status Status;
+  std::error_code EC = status(FD, Status);
+  SupportsSeeking = !EC && Status.type() == sys::fs::file_type::regular_file;
+#else
   SupportsSeeking = loc != (off_t)-1;
+#endif
   if (!SupportsSeeking)
     pos = 0;
   else