PR3478: raw_ostream should not buffer stderr

 - Add unbuffered flag to raw_ostream, forwarded by raw_fd_ostream and
   used by raw_stderr_ostream.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@66545 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 18 insertions, 4 deletions

diff --git a/include/llvm/Support/raw_ostream.h b/include/llvm/Support/raw_ostream.h
index 84fef39..0f1bee3 100644
--- a/include/llvm/Support/raw_ostream.h
+++ b/include/llvm/Support/raw_ostream.h
@@ -32,8 +32,10 @@ namespace llvm {
 class raw_ostream {
 protected:
   char *OutBufStart, *OutBufEnd, *OutBufCur;
+  bool Unbuffered;
+
 public:
-  raw_ostream() {
+  raw_ostream(bool unbuffered=false) : Unbuffered(unbuffered) {
     // Start out ready to flush.
     OutBufStart = OutBufEnd = OutBufCur = 0;
   }
@@ -59,6 +61,16 @@ public:
     OutBufCur = OutBufStart;
   }
 
+  /// SetUnbuffered - Set the streams buffering status. When
+  /// unbuffered the stream will flush after every write. This routine
+  /// will also flush the buffer immediately when the stream is being
+  /// set to unbuffered.
+  void SetUnbuffered(bool unbuffered) {
+    Unbuffered = unbuffered;
+    if (Unbuffered)
+      flush();
+  }
+
   //===--------------------------------------------------------------------===//
   // Data Output Interface
   //===--------------------------------------------------------------------===//
@@ -165,9 +177,11 @@ public:
   raw_fd_ostream(const char *Filename, bool Binary, std::string &ErrorInfo);
 
   /// raw_fd_ostream ctor - FD is the file descriptor that this writes to.  If
-  /// ShouldClose is true, this closes the file when
-  raw_fd_ostream(int fd, bool shouldClose) : FD(fd), ShouldClose(shouldClose) {}
-
+  /// ShouldClose is true, this closes the file when the stream is destroyed.
+  raw_fd_ostream(int fd, bool shouldClose, 
+                 bool unbuffered=false) : raw_ostream(unbuffered), FD(fd), 
+                                          ShouldClose(shouldClose) {}
+  
   ~raw_fd_ostream();
 
   /// flush_impl - The is the piece of the class that is implemented by