--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lib/Support/Debug.cpp	Thu Dec 12 13:56:28 2013 +0900
@@ -0,0 +1,134 @@
+//===-- Debug.cpp - An easy way to add debug output to your code ----------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements a handy way of adding debugging information to your
+// code, without it being enabled all of the time, and without having to add
+// command line options to enable it.
+//
+// In particular, just wrap your code with the DEBUG() macro, and it will be
+// enabled automatically if you specify '-debug' on the command-line.
+// Alternatively, you can also use the SET_DEBUG_TYPE("foo") macro to specify
+// that your debug code belongs to class "foo".  Then, on the command line, you
+// can specify '-debug-only=foo' to enable JUST the debug information for the
+// foo class.
+//
+// When compiling without assertions, the -debug-* options and all code in
+// DEBUG() statements disappears, so it does not affect the runtime of the code.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Signals.h"
+#include "llvm/Support/circular_raw_ostream.h"
+
+using namespace llvm;
+
+// All Debug.h functionality is a no-op in NDEBUG mode.
+#ifndef NDEBUG
+bool llvm::DebugFlag;  // DebugFlag - Exported boolean set by the -debug option
+
+// -debug - Command line option to enable the DEBUG statements in the passes.
+// This flag may only be enabled in debug builds.
+static cl::opt<bool, true>
+Debug("debug", cl::desc("Enable debug output"), cl::Hidden,
+      cl::location(DebugFlag));
+
+// -debug-buffer-size - Buffer the last N characters of debug output
+//until program termination.
+static cl::opt<unsigned>
+DebugBufferSize("debug-buffer-size",
+                cl::desc("Buffer the last N characters of debug output "
+                         "until program termination. "
+                         "[default 0 -- immediate print-out]"),
+                cl::Hidden,
+                cl::init(0));
+
+static std::string CurrentDebugType;
+
+namespace {
+
+struct DebugOnlyOpt {
+  void operator=(const std::string &Val) const {
+    DebugFlag |= !Val.empty();
+    CurrentDebugType = Val;
+  }
+};
+
+}
+
+static DebugOnlyOpt DebugOnlyOptLoc;
+
+static cl::opt<DebugOnlyOpt, true, cl::parser<std::string> >
+DebugOnly("debug-only", cl::desc("Enable a specific type of debug output"),
+          cl::Hidden, cl::value_desc("debug string"),
+          cl::location(DebugOnlyOptLoc), cl::ValueRequired);
+
+// Signal handlers - dump debug output on termination.
+static void debug_user_sig_handler(void *Cookie) {
+  // This is a bit sneaky.  Since this is under #ifndef NDEBUG, we
+  // know that debug mode is enabled and dbgs() really is a
+  // circular_raw_ostream.  If NDEBUG is defined, then dbgs() ==
+  // errs() but this will never be invoked.
+  llvm::circular_raw_ostream *dbgout =
+    static_cast<llvm::circular_raw_ostream *>(&llvm::dbgs());
+  dbgout->flushBufferWithBanner();
+}
+
+// isCurrentDebugType - Return true if the specified string is the debug type
+// specified on the command line, or if none was specified on the command line
+// with the -debug-only=X option.
+//
+bool llvm::isCurrentDebugType(const char *DebugType) {
+  return CurrentDebugType.empty() || DebugType == CurrentDebugType;
+}
+
+/// setCurrentDebugType - Set the current debug type, as if the -debug-only=X
+/// option were specified.  Note that DebugFlag also needs to be set to true for
+/// debug output to be produced.
+///
+void llvm::setCurrentDebugType(const char *Type) {
+  CurrentDebugType = Type;
+}
+
+/// dbgs - Return a circular-buffered debug stream.
+raw_ostream &llvm::dbgs() {
+  // Do one-time initialization in a thread-safe way.
+  static struct dbgstream {
+    circular_raw_ostream strm;
+
+    dbgstream() :
+        strm(errs(), "*** Debug Log Output ***\n",
+             (!EnableDebugBuffering || !DebugFlag) ? 0 : DebugBufferSize) {
+      if (EnableDebugBuffering && DebugFlag && DebugBufferSize != 0)
+        // TODO: Add a handler for SIGUSER1-type signals so the user can
+        // force a debug dump.
+        sys::AddSignalHandler(&debug_user_sig_handler, 0);
+      // Otherwise we've already set the debug stream buffer size to
+      // zero, disabling buffering so it will output directly to errs().
+    }
+  } thestrm;
+
+  return thestrm.strm;
+}
+
+#else
+// Avoid "has no symbols" warning.
+namespace llvm {
+  /// dbgs - Return errs().
+  raw_ostream &dbgs() {
+    return errs();
+  }
+}
+
+#endif
+
+/// EnableDebugBuffering - Turn on signal handler installation.
+///
+bool llvm::EnableDebugBuffering = false;