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/lib/Support/raw_ostream.cpp b/lib/Support/raw_ostream.cpp
index 0595fe4..b13d922 100644
--- a/lib/Support/raw_ostream.cpp
+++ b/lib/Support/raw_ostream.cpp
@@ -246,7 +246,7 @@
 /// occurs, information about the error is put into ErrorInfo, and the
 /// stream should be immediately destroyed; the string will be empty
 /// if no error occurred.
-raw_fd_ostream::raw_fd_ostream(const char *Filename, bool Binary,
+raw_fd_ostream::raw_fd_ostream(const char *Filename, bool Binary, bool Force,
                                std::string &ErrorInfo) : pos(0) {
   ErrorInfo.clear();
 
@@ -266,6 +266,8 @@
   if (Binary)
     Flags |= O_BINARY;
 #endif
+  if (!Force)
+    Flags |= O_EXCL;
   FD = open(Filename, Flags, 0664);
   if (FD < 0) {
     ErrorInfo = "Error opening output file '" + std::string(Filename) + "'";