rts: TraverseHeap: Make "flip" bit flip into it's own function

Note that this commit changes the sense of the flip bit in order to allow
doing the "flip" after traverseWorkStack.

3 files changed, 30 insertions, 13 deletions

diff --git a/rts/RetainerProfile.c b/rts/RetainerProfile.c
index 33a3b8d134..62f28ac439 100644
--- a/rts/RetainerProfile.c
+++ b/rts/RetainerProfile.c
@@ -407,6 +407,8 @@ computeRetainerSet( traverseState *ts )
     rememberOldStableNameAddresses ();
 
     traverseWorkStack(ts, &retainVisitClosure);
+
+    traverseInvalidateClosureData(ts);
 }
 
 /* -----------------------------------------------------------------------------
diff --git a/rts/TraverseHeap.c b/rts/TraverseHeap.c
index 524e11513e..436941ef64 100644
--- a/rts/TraverseHeap.c
+++ b/rts/TraverseHeap.c
@@ -24,12 +24,17 @@ StgWord getTravData(const StgClosure *c)
 
 void setTravData(const traverseState *ts, StgClosure *c, StgWord w)
 {
-    c->header.prof.hp.trav = w | ts->flip;
+    c->header.prof.hp.trav = w | !ts->flip;
+}
+
+STATIC_INLINE void invalidateTravData(const traverseState *ts, StgClosure *c)
+{
+    c->header.prof.hp.trav = ts->flip;
 }
 
 bool isTravDataValid(const traverseState *ts, const StgClosure *c)
 {
-    return (c->header.prof.hp.trav & 1) == ts->flip;
+    return (c->header.prof.hp.trav & 1) == !ts->flip;
 }
 
 typedef enum {
@@ -1162,7 +1167,6 @@ resetMutableObjects(traverseState* ts)
         for (n = 0; n < n_capabilities; n++) {
           for (bd = capabilities[n]->mut_lists[g]; bd != NULL; bd = bd->link) {
             for (ml = bd->start; ml < bd->free; ml++) {
-
                 traverseMaybeInitClosureData(ts, (StgClosure *)*ml);
             }
           }
@@ -1172,9 +1176,7 @@ resetMutableObjects(traverseState* ts)
 
 /**
  * Traverse all closures on the traversal work-stack, calling 'visit_cb' on each
- * closure. See 'visitClosure_cb' for details. This function flips the 'flip'
- * bit and hence every closure's profiling data will be reset to zero upon
- * visiting. See Note [Profiling heap traversal visited bit].
+ * closure. See 'visitClosure_cb' for details.
  */
 void
 traverseWorkStack(traverseState *ts, visitClosure_cb visit_cb)
@@ -1186,9 +1188,6 @@ traverseWorkStack(traverseState *ts, visitClosure_cb visit_cb)
     stackElement *sep;
     bool other_children;
 
-    // Now we flip the flip bit.
-    ts->flip = ts->flip ^ 1;
-
     // c = Current closure                           (possibly tagged)
     // cp = Current closure's Parent                 (NOT tagged)
     // data = current closures' associated data      (NOT tagged)
@@ -1199,7 +1198,6 @@ loop:
 
     if (c == NULL) {
         debug("maxStackSize= %d\n", ts->maxStackSize);
-        resetMutableObjects(ts);
         return;
     }
 
@@ -1401,6 +1399,22 @@ inner_loop:
 }
 
 /**
+ * This function flips the 'flip' bit and hence every closure's profiling data
+ * will be reset to zero upon visiting. See Note [Profiling heap traversal
+ * visited bit].
+ */
+void
+traverseInvalidateClosureData(traverseState* ts)
+{
+    // First make sure any unvisited mutable objects are valid so they're
+    // invalidated by the flip below
+    resetMutableObjects(ts);
+
+    // Then flip the flip bit, invalidating all closures.
+    ts->flip = ts->flip ^ 1;
+}
+
+/**
  *  Traverse all static objects for which we compute retainer sets,
  *  and reset their rs fields to NULL, which is accomplished by
  *  invoking traverseMaybeInitClosureData(). This function must be called
@@ -1444,7 +1458,7 @@ resetStaticObjectForProfiling( const traverseState *ts, StgClosure *static_objec
             p = (StgClosure*)*IND_STATIC_LINK(p);
             break;
         case THUNK_STATIC:
-            traverseMaybeInitClosureData(ts, p);
+            invalidateTravData(ts, p);
             p = (StgClosure*)*THUNK_STATIC_LINK(p);
             break;
         case FUN_STATIC:
@@ -1453,7 +1467,7 @@ resetStaticObjectForProfiling( const traverseState *ts, StgClosure *static_objec
         case CONSTR_2_0:
         case CONSTR_1_1:
         case CONSTR_NOCAF:
-            traverseMaybeInitClosureData(ts, p);
+            invalidateTravData(ts, p);
             p = (StgClosure*)*STATIC_LINK(get_itbl(p), p);
             break;
         default:
diff --git a/rts/TraverseHeap.h b/rts/TraverseHeap.h
index 30a9c187d9..0d55f376eb 100644
--- a/rts/TraverseHeap.h
+++ b/rts/TraverseHeap.h
@@ -55,7 +55,7 @@ typedef struct traverseState_ {
      * variable, 'flip' and "flip" this variable when we want to invalidate all
      * objects.
      *
-     * When the visited bit is equal to the value of 'flip' the closure data
+     * When the visited bit is not equal to the value of 'flip' the closure data
      * is valid otherwise not (see isTravDataValid). We then invert the value of
      * 'flip' after each each profiling run (see
      * traverseInvalidateAllProfHeaders).
@@ -162,6 +162,7 @@ bool isTravDataValid(const traverseState *ts, const StgClosure *c);
 void traverseWorkStack(traverseState *ts, visitClosure_cb visit_cb);
 void traversePushRoot(traverseState *ts, StgClosure *c, StgClosure *cp, stackData data);
 bool traverseMaybeInitClosureData(const traverseState* ts, StgClosure *c);
+void traverseInvalidateClosureData(traverseState* ts);
 
 void initializeTraverseStack(traverseState *ts);
 void closeTraverseStack(traverseState *ts);