--- a/lib/Support/raw_ostream.cpp	Thu Dec 12 15:22:36 2013 +0900
+++ b/lib/Support/raw_ostream.cpp	Mon Sep 08 22:06:00 2014 +0900
@@ -22,10 +22,10 @@
 #include "llvm/Support/Format.h"
 #include "llvm/Support/Process.h"
 #include "llvm/Support/Program.h"
-#include "llvm/Support/system_error.h"
 #include <cctype>
 #include <cerrno>
 #include <sys/stat.h>
+#include <system_error>
 
 // <fcntl.h> may provide O_BINARY.
 #if defined(HAVE_FCNTL_H)
@@ -87,8 +87,8 @@
 
 void raw_ostream::SetBufferAndMode(char *BufferStart, size_t Size,
                                    BufferKind Mode) {
-  assert(((Mode == Unbuffered && BufferStart == 0 && Size == 0) ||
-          (Mode != Unbuffered && BufferStart && Size)) &&
+  assert(((Mode == Unbuffered && !BufferStart && Size == 0) ||
+          (Mode != Unbuffered && BufferStart && Size != 0)) &&
          "stream must be unbuffered or have at least one byte");
   // Make sure the current buffer is free of content (we can't flush here; the
   // child buffer management logic will be in write_impl).
@@ -227,11 +227,17 @@
   // On MSVCRT and compatible, output of %e is incompatible to Posix
   // by default. Number of exponent digits should be at least 2. "%+03d"
   // FIXME: Implement our formatter to here or Support/Format.h!
+#if __cplusplus >= 201103L && defined(__MINGW32__)
+  // FIXME: It should be generic to C++11.
+  if (N == 0.0 && std::signbit(N))
+    return *this << "-0.000000e+00";
+#else
   int fpcl = _fpclass(N);
 
   // negative zero
   if (fpcl == _FPCLASS_NZ)
     return *this << "-0.000000e+00";
+#endif
 
   char buf[16];
   unsigned len;
@@ -420,35 +426,27 @@
 //  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; the string will be empty
-/// if no error occurred.
-raw_fd_ostream::raw_fd_ostream(const char *Filename, std::string &ErrorInfo,
+raw_fd_ostream::raw_fd_ostream(StringRef Filename, std::error_code &EC,
                                sys::fs::OpenFlags Flags)
     : Error(false), UseAtomicWrites(false), pos(0) {
-  assert(Filename != 0 && "Filename is null");
-  ErrorInfo.clear();
-
+  EC = std::error_code();
   // Handle "-" as stdout. Note that when we do this, we consider ourself
   // the owner of stdout. This means that we can do things like close the
   // file descriptor when we're done and set the "binary" flag globally.
-  if (Filename[0] == '-' && Filename[1] == 0) {
+  if (Filename == "-") {
     FD = STDOUT_FILENO;
     // If user requested binary then put stdout into binary mode if
     // possible.
-    if (Flags & sys::fs::F_Binary)
+    if (!(Flags & sys::fs::F_Text))
       sys::ChangeStdoutToBinary();
     // Close stdout when we're done, to detect any output errors.
     ShouldClose = true;
     return;
   }
 
-  error_code EC = sys::fs::openFileForWrite(Filename, FD, Flags);
+  EC = sys::fs::openFileForWrite(Filename, FD, Flags);
 
   if (EC) {
-    ErrorInfo = "Error opening output file '" + std::string(Filename) + "': " +
-                EC.message();
     ShouldClose = false;
     return;
   }
@@ -463,9 +461,10 @@
   : raw_ostream(unbuffered), FD(fd),
     ShouldClose(shouldClose), Error(false), UseAtomicWrites(false) {
 #ifdef O_BINARY
-  // Setting STDOUT and STDERR to binary mode is necessary in Win32
+  // Setting STDOUT to binary mode is necessary in Win32
   // to avoid undesirable linefeed conversion.
-  if (fd == STDOUT_FILENO || fd == STDERR_FILENO)
+  // Don't touch STDERR, or w*printf() (in assert()) would barf wide chars.
+  if (fd == STDOUT_FILENO)
     setmode(fd, O_BINARY);
 #endif
 
@@ -653,7 +652,7 @@
 /// Use it like: outs() << "foo" << "bar";
 raw_ostream &llvm::outs() {
   // Set buffer settings to model stdout behavior.
-  // Delete the file descriptor when the program exists, forcing error
+  // Delete the file descriptor when the program exits, forcing error
   // detection. If you don't want this behavior, don't use outs().
   static raw_fd_ostream S(STDOUT_FILENO, true);
   return S;
@@ -722,24 +721,17 @@
 }
 
 void raw_svector_ostream::write_impl(const char *Ptr, size_t Size) {
-  // If we're writing bytes from the end of the buffer into the smallvector, we
-  // don't need to copy the bytes, just commit the bytes because they are
-  // already in the right place.
   if (Ptr == OS.end()) {
-    assert(OS.size() + Size <= OS.capacity() && "Invalid write_impl() call!");
-    OS.set_size(OS.size() + Size);
+    // Grow the buffer to include the scratch area without copying.
+    size_t NewSize = OS.size() + Size;
+    assert(NewSize <= OS.capacity() && "Invalid write_impl() call!");
+    OS.set_size(NewSize);
   } else {
-    assert(GetNumBytesInBuffer() == 0 &&
-           "Should be writing from buffer if some bytes in it");
-    // Otherwise, do copy the bytes.
-    OS.append(Ptr, Ptr+Size);
+    assert(!GetNumBytesInBuffer());
+    OS.append(Ptr, Ptr + Size);
   }
 
-  // Grow the vector if necessary.
-  if (OS.capacity() - OS.size() < 64)
-    OS.reserve(OS.capacity() * 2);
-
-  // Update the buffer position.
+  OS.reserve(OS.size() + 64);
   SetBuffer(OS.end(), OS.capacity() - OS.size());
 }