base: Move TRACING_ON check into Flag::tracing().

Now DTRACE is simply an alias for Debug::x. We should keep it now for
compatibility, but it can be removed over time.

Change-Id: Icda18ff57126328e98e440e3a81bf13caa0c27df
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/45008
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>

src/base/debug.hh

@@ -48,6 +48,8 @@
 #include <string>
 #include <vector>
 
+#include "base/compiler.hh"
+
 namespace Debug {
 
 void breakpoint();
@@ -71,7 +73,7 @@ class Flag
     std::string name() const { return _name; }
     std::string desc() const { return _desc; }
 
-    bool tracing() const { return _tracing; }
+    bool tracing() const { return TRACING_ON && _tracing; }
 
     virtual void enable() = 0;
     virtual void disable() = 0;
@@ -150,7 +152,7 @@ void dumpDebugFlags(std::ostream &os=std::cout);
  * @ingroup api_trace
  * @{
  */
-#define DTRACE(x) (TRACING_ON && Debug::x)
+#define DTRACE(x) (Debug::x)
 /** @} */ // end of api_trace
 
 #endif // __BASE_DEBUG_HH__