Add a Force option to raw_fd_ostream to specify whether opening
an existing file is considered an error. Convert several tools
to use raw_fd_ostream instead of std::ostream, and to use this
new option instead of doing a manual check.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@75801 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/utils/TableGen/TableGen.cpp b/utils/TableGen/TableGen.cpp
index 376bec1..315bb65 100644
--- a/utils/TableGen/TableGen.cpp
+++ b/utils/TableGen/TableGen.cpp
@@ -171,7 +171,8 @@
   raw_ostream *Out = &outs();
   if (OutputFilename != "-") {
     std::string Error;
-    Out = new raw_fd_ostream(OutputFilename.c_str(), false, Error);
+    Out = new raw_fd_ostream(OutputFilename.c_str(), /*Binary=*/false,
+                             /*Force=*/true, Error);
 
     if (!Error.empty()) {
       errs() << argv[0] << ": error opening " << OutputFilename