fix bug #664 in printSample()

[ghc-hetmet.git] / ghc / rts / GC.c

diff --git a/ghc/rts/GC.c b/ghc/rts/GC.c
index 566ccef..7ce6a8f 100644 (file)
--- a/ghc/rts/GC.c
+++ b/ghc/rts/GC.c
@@ -1941,7 +1941,8 @@ loop:
   
   switch (info->type) {
 
-  case MUT_VAR:
+  case MUT_VAR_CLEAN:
+  case MUT_VAR_DIRTY:
   case MVAR:
       return copy(q,sizeW_fromITBL(info),stp);
 
@@ -2894,13 +2895,22 @@ scavenge(step *stp)
        p += sizeofW(StgInd);
        break;
 
-    case MUT_VAR:
-       evac_gen = 0;
+    case MUT_VAR_CLEAN:
+    case MUT_VAR_DIRTY: {
+       rtsBool saved_eager_promotion = eager_promotion;
+
+       eager_promotion = rtsFalse;
        ((StgMutVar *)p)->var = evacuate(((StgMutVar *)p)->var);
-       evac_gen = saved_evac_gen;
-       failed_to_evac = rtsTrue; // mutable anyhow
+       eager_promotion = saved_eager_promotion;
+
+       if (failed_to_evac) {
+           ((StgClosure *)q)->header.info = &stg_MUT_VAR_DIRTY_info;
+       } else {
+           ((StgClosure *)q)->header.info = &stg_MUT_VAR_CLEAN_info;
+       }
        p += sizeofW(StgMutVar);
        break;
+    }
 
     case CAF_BLACKHOLE:
     case SE_CAF_BLACKHOLE:
@@ -2994,10 +3004,19 @@ scavenge(step *stp)
     case TSO:
     { 
        StgTSO *tso = (StgTSO *)p;
-       evac_gen = 0;
+       rtsBool saved_eager = eager_promotion;
+
+       eager_promotion = rtsFalse;
        scavengeTSO(tso);
-       evac_gen = saved_evac_gen;
-       failed_to_evac = rtsTrue; // mutable anyhow.
+       eager_promotion = saved_eager;
+
+       if (failed_to_evac) {
+           tso->flags |= TSO_DIRTY;
+       } else {
+           tso->flags &= ~TSO_DIRTY;
+       }
+
+       failed_to_evac = rtsTrue; // always on the mutable list
        p += tso_sizeW(tso);
        break;
     }
@@ -3277,12 +3296,21 @@ linear_scan:
                evacuate(((StgInd *)p)->indirectee);
            break;
 
-       case MUT_VAR:
-           evac_gen = 0;
+       case MUT_VAR_CLEAN:
+       case MUT_VAR_DIRTY: {
+           rtsBool saved_eager_promotion = eager_promotion;
+           
+           eager_promotion = rtsFalse;
            ((StgMutVar *)p)->var = evacuate(((StgMutVar *)p)->var);
-           evac_gen = saved_evac_gen;
-           failed_to_evac = rtsTrue;
+           eager_promotion = saved_eager_promotion;
+           
+           if (failed_to_evac) {
+               ((StgClosure *)q)->header.info = &stg_MUT_VAR_DIRTY_info;
+           } else {
+               ((StgClosure *)q)->header.info = &stg_MUT_VAR_CLEAN_info;
+           }
            break;
+       }
 
        case CAF_BLACKHOLE:
        case SE_CAF_BLACKHOLE:
@@ -3369,10 +3397,19 @@ linear_scan:
        case TSO:
        { 
            StgTSO *tso = (StgTSO *)p;
-           evac_gen = 0;
+           rtsBool saved_eager = eager_promotion;
+
+           eager_promotion = rtsFalse;
            scavengeTSO(tso);
-           evac_gen = saved_evac_gen;
-           failed_to_evac = rtsTrue;
+           eager_promotion = saved_eager;
+           
+           if (failed_to_evac) {
+               tso->flags |= TSO_DIRTY;
+           } else {
+               tso->flags &= ~TSO_DIRTY;
+           }
+           
+           failed_to_evac = rtsTrue; // always on the mutable list
            break;
        }
 
@@ -3607,12 +3644,22 @@ scavenge_one(StgPtr p)
        break;
     }
     
-    case MUT_VAR:
-       evac_gen = 0;
+    case MUT_VAR_CLEAN:
+    case MUT_VAR_DIRTY: {
+       StgPtr q = p;
+       rtsBool saved_eager_promotion = eager_promotion;
+
+       eager_promotion = rtsFalse;
        ((StgMutVar *)p)->var = evacuate(((StgMutVar *)p)->var);
-       evac_gen = saved_evac_gen;
-       failed_to_evac = rtsTrue; // mutable anyhow
+       eager_promotion = saved_eager_promotion;
+
+       if (failed_to_evac) {
+           ((StgClosure *)q)->header.info = &stg_MUT_VAR_DIRTY_info;
+       } else {
+           ((StgClosure *)q)->header.info = &stg_MUT_VAR_CLEAN_info;
+       }
        break;
+    }
 
     case CAF_BLACKHOLE:
     case SE_CAF_BLACKHOLE:
@@ -3702,11 +3749,19 @@ scavenge_one(StgPtr p)
     case TSO:
     {
        StgTSO *tso = (StgTSO *)p;
-      
-       evac_gen = 0;           // repeatedly mutable 
+       rtsBool saved_eager = eager_promotion;
+
+       eager_promotion = rtsFalse;
        scavengeTSO(tso);
-       evac_gen = saved_evac_gen;
-       failed_to_evac = rtsTrue;
+       eager_promotion = saved_eager;
+
+       if (failed_to_evac) {
+           tso->flags |= TSO_DIRTY;
+       } else {
+           tso->flags &= ~TSO_DIRTY;
+       }
+
+       failed_to_evac = rtsTrue; // always on the mutable list
        break;
     }
   
@@ -3892,7 +3947,9 @@ scavenge_mutable_list(generation *gen)
 
 #ifdef DEBUG       
            switch (get_itbl((StgClosure *)p)->type) {
-           case MUT_VAR:
+           case MUT_VAR_CLEAN:
+               barf("MUT_VAR_CLEAN on mutable list");
+           case MUT_VAR_DIRTY:
                mutlist_MUTVARS++; break;
            case MUT_ARR_PTRS_CLEAN:
            case MUT_ARR_PTRS_DIRTY:
@@ -3904,17 +3961,38 @@ scavenge_mutable_list(generation *gen)
            }
 #endif
 
-           // We don't need to scavenge clean arrays.  This is the
-           // Whole Point of MUT_ARR_PTRS_CLEAN.
-           if (get_itbl((StgClosure *)p)->type == MUT_ARR_PTRS_CLEAN) {
+           // Check whether this object is "clean", that is it
+           // definitely doesn't point into a young generation.
+           // Clean objects don't need to be scavenged.  Some clean
+           // objects (MUT_VAR_CLEAN) are not kept on the mutable
+           // list at all; others, such as MUT_ARR_PTRS_CLEAN and
+           // TSO, are always on the mutable list.
+           //
+           switch (get_itbl((StgClosure *)p)->type) {
+           case MUT_ARR_PTRS_CLEAN:
                recordMutableGen((StgClosure *)p,gen);
                continue;
+           case TSO: {
+               StgTSO *tso = (StgTSO *)p;
+               if ((tso->flags & TSO_DIRTY) == 0) {
+                   // A clean TSO: we don't have to traverse its
+                   // stack.  However, we *do* follow the link field:
+                   // we don't want to have to mark a TSO dirty just
+                   // because we put it on a different queue.
+                   if (tso->why_blocked != BlockedOnBlackHole) {
+                       tso->link = (StgTSO *)evacuate((StgClosure *)tso->link);
+                   }
+                   recordMutableGen((StgClosure *)p,gen);
+                   continue;
+               }
+           }
+           default:
+               ;
            }
 
            if (scavenge_one(p)) {
-               /* didn't manage to promote everything, so put the
-                * object back on the list.
-                */
+               // didn't manage to promote everything, so put the
+               // object back on the list.
                recordMutableGen((StgClosure *)p,gen);
            }
        }