add a new 'SetCurrentDebugType' API (requested by Andrew Haley for JIT
stuff) to programmatically control the current debug flavor.  While 
I'm at it, doxygenate Debug.h and clean it up.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85395 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/llvm/Support/Debug.h b/include/llvm/Support/Debug.h
index 6f82ea7..afa828c 100644
--- a/include/llvm/Support/Debug.h
+++ b/include/llvm/Support/Debug.h
@@ -28,39 +28,47 @@
 
 namespace llvm {
 
-// DebugFlag - This boolean is set to true if the '-debug' command line option
-// is specified.  This should probably not be referenced directly, instead, use
-// the DEBUG macro below.
-//
+/// DEBUG_TYPE macro - Files can specify a DEBUG_TYPE as a string, which causes
+/// all of their DEBUG statements to be activatable with -debug-only=thatstring.
+#ifndef DEBUG_TYPE
+#define DEBUG_TYPE ""
+#endif
+  
 #ifndef NDEBUG
+/// DebugFlag - This boolean is set to true if the '-debug' command line option
+/// is specified.  This should probably not be referenced directly, instead, use
+/// the DEBUG macro below.
+///
 extern bool DebugFlag;
-#endif
-
-// 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.
-//
-#ifndef NDEBUG
+  
+/// 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 isCurrentDebugType(const char *Type);
-#else
-#define isCurrentDebugType(X) (false)
-#endif
 
-// 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", errs() << "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".
-
-#ifdef NDEBUG
-#define DEBUG_WITH_TYPE(TYPE, X) do { } while (0)
-#else
+/// 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", errs() << "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 (DebugFlag && isCurrentDebugType(TYPE)) { X; } } while (0)
+
+#else
+#define isCurrentDebugType(X) (false)
+#define SetCurrentDebugType(X)
+#define DEBUG_WITH_TYPE(TYPE, X) do { } while (0)
 #endif
 
 // DEBUG macro - This macro should be used by passes to emit debug information.
@@ -70,11 +78,6 @@
 //
 // DEBUG(errs() << "Bitset contains: " << Bitset << "\n");
 //
-
-#ifndef DEBUG_TYPE
-#define DEBUG_TYPE ""
-#endif
-
 #define DEBUG(X) DEBUG_WITH_TYPE(DEBUG_TYPE, X)
   
 } // End llvm namespace
diff --git a/lib/Support/Debug.cpp b/lib/Support/Debug.cpp
index 71ff411..d4954b6 100644
--- a/lib/Support/Debug.cpp
+++ b/lib/Support/Debug.cpp
@@ -57,7 +57,18 @@
 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 SetCurrentDebugType(const char *Type) {
+  CurrentDebugType = Type;
+}
+
 #else
 // Avoid "has no symbols" warning.
+namespace llvm {
 int Debug_dummy = 0;
+}
 #endif