+/// 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 setCurrentDebugType(const char *Type);
+
+/// DEBUG_WITH_TYPE macro - This macro should be used by passes to emit debug
+/// information. In the '-debug' option is specified on the commandline, and if
+/// this is a debug build, then the code specified as the option to the macro
+/// will be executed. Otherwise it will not be. Example:
+///
+/// DEBUG_WITH_TYPE("bitset", dbgs() << "Bitset contains: " << Bitset << "\n");
+///
+/// This will emit the debug information if -debug is present, and -debug-only
+/// is not specified, or is specified as "bitset".
+#define DEBUG_WITH_TYPE(TYPE, X) \
+ do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType(TYPE)) { X; } \
+ } while (0)
+
+#else
+#define isCurrentDebugType(X) (false)
+#define setCurrentDebugType(X)
+#define DEBUG_WITH_TYPE(TYPE, X) do { } while (0)
+#endif
+
+/// EnableDebugBuffering - This defaults to false. If true, the debug
+/// stream will install signal handlers to dump any buffered debug
+/// output. It allows clients to selectively allow the debug stream
+/// to install signal handlers if they are certain there will be no
+/// conflict.
+///
+extern bool EnableDebugBuffering;
+
+/// dbgs() - This returns a reference to a raw_ostream for debugging
+/// messages. If debugging is disabled it returns errs(). Use it
+/// like: dbgs() << "foo" << "bar";
+raw_ostream &dbgs();
+