[Support] Use realpath(3) instead of trying to open a file.

If we don't have read permissions on the directory the call would
fail.

<rdar://problem/35871293>

llvm-svn: 322095

1 files changed, 6 insertions, 6 deletions

diff --git a/llvm/lib/Support/Unix/Path.inc b/llvm/lib/Support/Unix/Path.inc
index 2ecb97316c8..220162d1c19 100644
--- a/llvm/lib/Support/Unix/Path.inc
+++ b/llvm/lib/Support/Unix/Path.inc
@@ -860,12 +860,12 @@ std::error_code real_path(const Twine &path, SmallVectorImpl<char> &dest,
     return real_path(Storage, dest, false);
   }
 
-  int fd;
-  std::error_code EC = openFileForRead(path, fd, &dest);
-
-  if (EC)
-    return EC;
-  ::close(fd);
+  SmallString<128> Storage;
+  StringRef P = path.toNullTerminatedStringRef(Storage);
+  char Buffer[PATH_MAX];
+  if (::realpath(P.begin(), Buffer) == nullptr)
+    return std::error_code(errno, std::generic_category());
+  dest.append(Buffer, Buffer + strlen(Buffer));
   return std::error_code();
 }