add a new raw_ostream class which is an extremely high performance ostream that

can *only* output data (no seeking, reading, etc).  This is adapted from the
clang "-E outputter", and is roughly 10% faster than stdio on darwin and 30%
(or more) faster than std::ostream.

llvm-svn: 54855

1 files changed, 64 insertions, 0 deletions

diff --git a/llvm/lib/Support/raw_ostream.cpp b/llvm/lib/Support/raw_ostream.cpp
new file mode 100644
index 00000000000..ec7ac6d0074
--- /dev/null
+++ b/llvm/lib/Support/raw_ostream.cpp
@@ -0,0 +1,64 @@
+//===--- raw_ostream.cpp - Implement the raw_ostream classes --------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This implements support for bulk buffered stream output.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Support/raw_ostream.h"
+using namespace llvm;
+
+#if !defined(_MSC_VER)
+#include <fcntl.h>
+#else
+#include <io.h>
+#define open(x,y,z) _open(x,y)
+#define write(fd, start, size) _write(fd, start, size)
+#define close(fd) _close(fd)
+#endif
+
+// An out of line virtual method to provide a home for the class vtable.
+void raw_ostream::handle() {}
+
+//===----------------------------------------------------------------------===//
+//  raw_fd_ostream
+//===----------------------------------------------------------------------===//
+
+/// raw_fd_ostream - Open the specified file for writing.  If an error occurs,
+/// information about the error is put into ErrorInfo, and the stream should
+/// be immediately destroyed.
+raw_fd_ostream::raw_fd_ostream(const char *Filename, std::string &ErrorInfo) {
+  FD = open(Filename, O_WRONLY|O_CREAT|O_TRUNC, 0644);
+  if (FD < 0) {
+    ErrorInfo = "Error opening output file '" + std::string(Filename) + "'";
+    ShouldClose = false;
+  } else {
+    ShouldClose = true;
+  }
+}
+
+raw_fd_ostream::~raw_fd_ostream() {
+  flush();
+  if (ShouldClose)
+    close(FD);
+}
+
+void raw_fd_ostream::flush_impl() {
+  if (OutBufCur-OutBufStart)
+    write(FD, OutBufStart, OutBufCur-OutBufStart);
+  HandleFlush();
+}
+
+
+raw_stdout_ostream::raw_stdout_ostream():raw_fd_ostream(STDOUT_FILENO, false) {}
+raw_stderr_ostream::raw_stderr_ostream():raw_fd_ostream(STDERR_FILENO, false) {}
+
+// An out of line virtual method to provide a home for the class vtable.
+void raw_stdout_ostream::handle() {}
+void raw_stderr_ostream::handle() {}