rts: TraverseHeap: Make trav. data macros into functions

This allows the global 'flip' variable not to be exported. This allows a
future commit to also make it part of the traversalState struct.

rts/RetainerProfile.c

@@ -251,7 +251,14 @@ associate( StgClosure *c, RetainerSet *s )
 {
     // StgWord has the same size as pointers, so the following type
     // casting is okay.
-    RSET(c) = ((StgWord)s | flip);
+    setTravData(c, (StgWord)s);
+}
+
+inline RetainerSet*
+retainerSetOf( const StgClosure *c )
+{
+    ASSERT(isTravDataValid(c));
+    return (RetainerSet*)getTravData(c);
 }
 
 static bool

rts/RetainerProfile.h

@@ -20,17 +20,7 @@ void initRetainerProfiling ( void );
 void endRetainerProfiling  ( void );
 void retainerProfile       ( void );
 
-// extract the retainer set field from c
-#define RSET(c)   ((c)->header.prof.hp.trav)
-
-static inline RetainerSet *
-retainerSetOf( const StgClosure *c )
-{
-    ASSERT( isTravDataValid(c) );
-    // StgWord has the same size as pointers, so the following type
-    // casting is okay.
-    return (RetainerSet *)((StgWord)RSET(c) ^ flip);
-}
+RetainerSet* retainerSetOf( const StgClosure *c );
 
 // Used by GC.c
 W_ retainerStackBlocks(void);

rts/TraverseHeap.c

@@ -46,10 +46,23 @@
  * mutable data. There we do just go over all existing objects to reset the bit
  * manually. See 'resetStaticObjectForProfiling' and 'resetMutableObjects'.
  */
-StgWord flip = 0;
+static StgWord flip = 0;
 
-#define setTravDataToZero(c) \
-  (c)->header.prof.hp.trav = flip
+StgWord getTravData(const StgClosure *c)
+{
+    const StgWord hp_hdr = c->header.prof.hp.trav;
+    return hp_hdr & (STG_WORD_MAX ^ 1);
+}
+
+void setTravData(StgClosure *c, StgWord w)
+{
+    c->header.prof.hp.trav = w | flip;
+}
+
+bool isTravDataValid(const StgClosure *c)
+{
+    return ((c->header.prof.hp.trav & 1) ^ flip) == 0;
+}
 
 typedef enum {
     // Object with fixed layout. Keeps an information about that
@@ -949,7 +962,7 @@ bool
 traverseMaybeInitClosureData(StgClosure *c)
 {
     if (!isTravDataValid(c)) {
-        setTravDataToZero(c);
+        setTravData(c, 0);
         return true;
     }
     return false;

rts/TraverseHeap.h

@@ -18,12 +18,6 @@
 
 void resetStaticObjectForProfiling(StgClosure *static_objects);
 
-/* See Note [Profiling heap traversal visited bit]. */
-extern StgWord flip;
-
-#define isTravDataValid(c) \
-  ((((StgWord)(c)->header.prof.hp.trav & 1) ^ flip) == 0)
-
 typedef struct traverseState_ traverseState;
 
 typedef union stackData_ {
@@ -128,6 +122,10 @@ typedef bool (*visitClosure_cb) (
     stackAccum *accum,
     stackData *child_data);
 
+StgWord getTravData(const StgClosure *c);
+void setTravData(StgClosure *c, StgWord w);
+bool isTravDataValid(const StgClosure *c);
+
 void traverseWorkStack(traverseState *ts, visitClosure_cb visit_cb);
 void traversePushRoot(traverseState *ts, StgClosure *c, StgClosure *cp, stackData data);
 bool traverseMaybeInitClosureData(StgClosure *c);