X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=rts%2Fsm%2FEvac.c;h=fb9f4c49b2decb7a3e1833d1d12ae357a4ce2857;hb=698364afaf2f346227910c0cf8d4f1929cdc56ef;hp=ad577af0c9edb8ae555ac59d007eafe581a16fe3;hpb=2018c430c8eb41cc323616536fffb5830a1e3a65;p=ghc-hetmet.git

diff --git a/rts/sm/Evac.c b/rts/sm/Evac.c
index ad577af..fb9f4c4 100644
--- a/rts/sm/Evac.c
+++ b/rts/sm/Evac.c
@@ -23,71 +23,134 @@
 
 /* Used to avoid long recursion due to selector thunks
  */
-lnat thunk_selector_depth = 0;
 #define MAX_THUNK_SELECTOR_DEPTH 16
 
 static StgClosure * eval_thunk_selector (StgSelector * p, rtsBool);
 
-STATIC_INLINE void 
-upd_evacuee(StgClosure *p, StgClosure *dest)
+STATIC_INLINE StgPtr
+alloc_for_copy (nat size, step *stp)
 {
-    // not true: (ToDo: perhaps it should be)
-    // ASSERT(Bdescr((P_)dest)->flags & BF_EVACUATED);
-    SET_INFO(p, &stg_EVACUATED_info);
-    ((StgEvacuated *)p)->evacuee = dest;
+    StgPtr to;
+    step_workspace *ws;
+    bdescr *bd;
+
+    /* Find out where we're going, using the handy "to" pointer in 
+     * the step of the source object.  If it turns out we need to
+     * evacuate to an older generation, adjust it here (see comment
+     * by evacuate()).
+     */
+    if (stp->gen_no < gct->evac_gen) {
+	if (gct->eager_promotion) {
+	    stp = &generations[gct->evac_gen].steps[0];
+	} else {
+	    gct->failed_to_evac = rtsTrue;
+	}
+    }
+    
+    ws = &gct->steps[stp->gen_no][stp->no];
+    
+    /* chain a new block onto the to-space for the destination step if
+     * necessary.
+     */
+    bd = ws->todo_bd;
+    to = bd->free;
+    if (to + size >= bd->start + BLOCK_SIZE_W) {
+	bd = gc_alloc_todo_block(ws);
+	to = bd->free;
+    }
+    bd->free = to + size;
+
+    return to;
 }
+  
+STATIC_INLINE StgPtr
+alloc_for_copy_noscav (nat size, step *stp)
+{
+    StgPtr to;
+    step_workspace *ws;
+    bdescr *bd;
 
+    /* Find out where we're going, using the handy "to" pointer in 
+     * the step of the source object.  If it turns out we need to
+     * evacuate to an older generation, adjust it here (see comment
+     * by evacuate()).
+     */
+    if (stp->gen_no < gct->evac_gen) {
+	if (gct->eager_promotion) {
+	    stp = &generations[gct->evac_gen].steps[0];
+	} else {
+	    gct->failed_to_evac = rtsTrue;
+	}
+    }
+    
+    ws = &gct->steps[stp->gen_no][stp->no];
+    
+    /* chain a new block onto the to-space for the destination step if
+     * necessary.
+     */
+    bd = ws->scavd_list;
+    to = bd->free;
+    if (to + size >= bd->start + BLOCK_SIZE_W) {
+	bd = gc_alloc_scavd_block(ws);
+	to = bd->free;
+    }
+    bd->free = to + size;
 
+    return to;
+}
+  
 STATIC_INLINE StgClosure *
 copy_tag(StgClosure *src, nat size, step *stp,StgWord tag)
 {
   StgPtr to, from;
   nat i;
-#ifdef PROFILING
-  // @LDV profiling
-  nat size_org = size;
+  StgWord info;
+
+#ifdef THREADED_RTS
+    do {
+	info = xchg((StgPtr)&src->header.info, (W_)&stg_WHITEHOLE_info);
+	// so..  what is it?
+    } while (info == (W_)&stg_WHITEHOLE_info);
+    if (info == (W_)&stg_EVACUATED_info) {
+	src->header.info = (const StgInfoTable *)info;
+	return evacuate(src); // does the failed_to_evac stuff
+    }
+#else
+    info = (W_)src->header.info;
+    src->header.info = &stg_EVACUATED_info;
 #endif
 
-  TICK_GC_WORDS_COPIED(size);
-  /* Find out where we're going, using the handy "to" pointer in 
-   * the step of the source object.  If it turns out we need to
-   * evacuate to an older generation, adjust it here (see comment
-   * by evacuate()).
-   */
-  if (stp->gen_no < evac_gen) {
-      if (eager_promotion) {
-	  stp = &generations[evac_gen].steps[0];
-      } else {
-	  failed_to_evac = rtsTrue;
-      }
-  }
-
-  /* chain a new block onto the to-space for the destination step if
-   * necessary.
-   */
-  if (stp->hp + size >= stp->hpLim) {
-    gc_alloc_block(stp);
-  }
+    to = alloc_for_copy(size,stp);
+    
+    TICK_GC_WORDS_COPIED(size);
 
-  to = stp->hp;
-  from = (StgPtr)src;
-  stp->hp = to + size;
-  for (i = 0; i < size; i++) { // unroll for small i
-      to[i] = from[i];
-  }
+    from = (StgPtr)src;
+    to[0] = info;
+    for (i = 1; i < size; i++) { // unroll for small i
+	to[i] = from[i];
+    }
+    
+    // retag pointer before updating EVACUATE closure and returning
+    to = (StgPtr)TAG_CLOSURE(tag,(StgClosure*)to);
 
-  /* retag pointer before updating EVACUATE closure and returning */
-  to = (StgPtr)TAG_CLOSURE(tag,(StgClosure*)to);
+//  if (to+size+2 < bd->start + BLOCK_SIZE_W) {
+//      __builtin_prefetch(to + size + 2, 1);
+//  }
 
-  upd_evacuee((StgClosure *)from,(StgClosure *)to);
+    ((StgEvacuated*)from)->evacuee = (StgClosure *)to;
+#ifdef THREADED_RTS
+    write_barrier();
+    ((StgEvacuated*)from)->header.info = &stg_EVACUATED_info;
+#endif
 
 #ifdef PROFILING
-  // We store the size of the just evacuated object in the LDV word so that
-  // the profiler can guess the position of the next object later.
-  SET_EVACUAEE_FOR_LDV(from, size_org);
+    // We store the size of the just evacuated object in the LDV word so that
+    // the profiler can guess the position of the next object later.
+    SET_EVACUAEE_FOR_LDV(from, size);
 #endif
-  return (StgClosure *)to;
+    return (StgClosure *)to;
 }
+  
 
 // Same as copy() above, except the object will be allocated in memory
 // that will not be scavenged.  Used for object that have no pointer
@@ -95,100 +158,100 @@ copy_tag(StgClosure *src, nat size, step *stp,StgWord tag)
 STATIC_INLINE StgClosure *
 copy_noscav_tag(StgClosure *src, nat size, step *stp, StgWord tag)
 {
-  StgPtr to, from;
-  nat i;
-#ifdef PROFILING
-  // @LDV profiling
-  nat size_org = size;
+    StgPtr to, from;
+    nat i;
+    StgWord info;
+
+#ifdef THREADED_RTS
+    do {
+	info = xchg((StgPtr)&src->header.info, (W_)&stg_WHITEHOLE_info);
+    } while (info == (W_)&stg_WHITEHOLE_info);
+    if (info == (W_)&stg_EVACUATED_info) {
+	src->header.info = (const StgInfoTable *)info;
+	return evacuate(src); // does the failed_to_evac stuff
+    }
+#else
+    info = (W_)src->header.info;
+    src->header.info = &stg_EVACUATED_info;
 #endif
+    
+    to = alloc_for_copy_noscav(size,stp);
 
-  TICK_GC_WORDS_COPIED(size);
-  /* Find out where we're going, using the handy "to" pointer in 
-   * the step of the source object.  If it turns out we need to
-   * evacuate to an older generation, adjust it here (see comment
-   * by evacuate()).
-   */
-  if (stp->gen_no < evac_gen) {
-      if (eager_promotion) {
-	  stp = &generations[evac_gen].steps[0];
-      } else {
-	  failed_to_evac = rtsTrue;
-      }
-  }
-
-  /* chain a new block onto the to-space for the destination step if
-   * necessary.
-   */
-  if (stp->scavd_hp + size >= stp->scavd_hpLim) {
-    gc_alloc_scavd_block(stp);
-  }
-
-  to = stp->scavd_hp;
-  from = (StgPtr)src;
-  stp->scavd_hp = to + size;
-  for (i = 0; i < size; i++) { // unroll for small i
-      to[i] = from[i];
-  }
-
-  /* retag pointer before updating EVACUATE closure and returning */
-  to = (StgPtr)TAG_CLOSURE(tag,(StgClosure*)to);
+    TICK_GC_WORDS_COPIED(size);
+    
+    from = (StgPtr)src;
+    to[0] = info;
+    for (i = 1; i < size; i++) { // unroll for small i
+	to[i] = from[i];
+    }
 
-  upd_evacuee((StgClosure *)from,(StgClosure *)to);
+    // retag pointer before updating EVACUATE closure and returning
+    to = (StgPtr)TAG_CLOSURE(tag,(StgClosure*)to);
 
+    ((StgEvacuated*)from)->evacuee = (StgClosure *)to;
+#ifdef THREADED_RTS
+    write_barrier();
+    ((StgEvacuated*)from)->header.info = &stg_EVACUATED_info;
+#endif
+    
 #ifdef PROFILING
-  // We store the size of the just evacuated object in the LDV word so that
-  // the profiler can guess the position of the next object later.
-  SET_EVACUAEE_FOR_LDV(from, size_org);
+    // We store the size of the just evacuated object in the LDV word so that
+    // the profiler can guess the position of the next object later.
+    SET_EVACUAEE_FOR_LDV(from, size);
 #endif
-  return (StgClosure *)to;
+    return (StgClosure *)to;
 }
 
+
 /* Special version of copy() for when we only want to copy the info
  * pointer of an object, but reserve some padding after it.  This is
  * used to optimise evacuation of BLACKHOLEs.
  */
-
-
 static StgClosure *
 copyPart(StgClosure *src, nat size_to_reserve, nat size_to_copy, step *stp)
 {
-  P_ dest, to, from;
-#ifdef PROFILING
-  // @LDV profiling
-  nat size_to_copy_org = size_to_copy;
+    StgPtr to, from;
+    nat i;
+    StgWord info;
+    
+#ifdef THREADED_RTS
+    do {
+	info = xchg((StgPtr)&src->header.info, (W_)&stg_WHITEHOLE_info);
+    } while (info == (W_)&stg_WHITEHOLE_info);
+    if (info == (W_)&stg_EVACUATED_info) {
+	src->header.info = (const StgInfoTable *)info;
+	return evacuate(src); // does the failed_to_evac stuff
+    }
+#else
+    info = (W_)src->header.info;
+    src->header.info = &stg_EVACUATED_info;
 #endif
+    
+    to = alloc_for_copy(size_to_reserve, stp);
 
-  TICK_GC_WORDS_COPIED(size_to_copy);
-  if (stp->gen_no < evac_gen) {
-      if (eager_promotion) {
-	  stp = &generations[evac_gen].steps[0];
-      } else {
-	  failed_to_evac = rtsTrue;
-      }
-  }
-
-  if (stp->hp + size_to_reserve >= stp->hpLim) {
-    gc_alloc_block(stp);
-  }
+    TICK_GC_WORDS_COPIED(size_to_copy);
 
-  for(to = stp->hp, from = (P_)src; size_to_copy>0; --size_to_copy) {
-    *to++ = *from++;
-  }
-  
-  dest = stp->hp;
-  stp->hp += size_to_reserve;
-  upd_evacuee(src,(StgClosure *)dest);
+    from = (StgPtr)src;
+    to[0] = info;
+    for (i = 1; i < size_to_copy; i++) { // unroll for small i
+	to[i] = from[i];
+    }
+    
+    ((StgEvacuated*)from)->evacuee = (StgClosure *)to;
+#ifdef THREADED_RTS
+    write_barrier();
+    ((StgEvacuated*)from)->header.info = &stg_EVACUATED_info;
+#endif
+    
 #ifdef PROFILING
-  // We store the size of the just evacuated object in the LDV word so that
-  // the profiler can guess the position of the next object later.
-  // size_to_copy_org is wrong because the closure already occupies size_to_reserve
-  // words.
-  SET_EVACUAEE_FOR_LDV(src, size_to_reserve);
-  // fill the slop
-  if (size_to_reserve - size_to_copy_org > 0)
-    LDV_FILL_SLOP(stp->hp - 1, (int)(size_to_reserve - size_to_copy_org)); 
+    // We store the size of the just evacuated object in the LDV word so that
+    // the profiler can guess the position of the next object later.
+    SET_EVACUAEE_FOR_LDV(from, size_to_reserve);
+    // fill the slop
+    if (size_to_reserve - size_to_copy > 0)
+	LDV_FILL_SLOP(to + size_to_copy - 1, (int)(size_to_reserve - size_to_copy)); 
 #endif
-  return (StgClosure *)dest;
+    return (StgClosure *)to;
 }
 
 
@@ -222,6 +285,7 @@ evacuate_large(StgPtr p)
 {
   bdescr *bd = Bdescr(p);
   step *stp;
+  step_workspace *ws;
 
   // object must be at the beginning of the block (or be a ByteArray)
   ASSERT(get_itbl((StgClosure *)p)->type == ARR_WORDS ||
@@ -229,17 +293,19 @@ evacuate_large(StgPtr p)
 
   // already evacuated? 
   if (bd->flags & BF_EVACUATED) { 
-    /* Don't forget to set the failed_to_evac flag if we didn't get
+    /* Don't forget to set the gct->failed_to_evac flag if we didn't get
      * the desired destination (see comments in evacuate()).
      */
-    if (bd->gen_no < evac_gen) {
-      failed_to_evac = rtsTrue;
+    if (bd->gen_no < gct->evac_gen) {
+      gct->failed_to_evac = rtsTrue;
       TICK_GC_FAILED_PROMOTION();
     }
     return;
   }
 
   stp = bd->step;
+
+  ACQUIRE_SPIN_LOCK(&stp->sync_large_objects);
   // remove from large_object list 
   if (bd->u.back) {
     bd->u.back->link = bd->link;
@@ -249,22 +315,24 @@ evacuate_large(StgPtr p)
   if (bd->link) {
     bd->link->u.back = bd->u.back;
   }
+  RELEASE_SPIN_LOCK(&stp->sync_large_objects);
   
   /* link it on to the evacuated large object list of the destination step
    */
   stp = bd->step->to;
-  if (stp->gen_no < evac_gen) {
-      if (eager_promotion) {
-	  stp = &generations[evac_gen].steps[0];
+  if (stp->gen_no < gct->evac_gen) {
+      if (gct->eager_promotion) {
+	  stp = &generations[gct->evac_gen].steps[0];
       } else {
-	  failed_to_evac = rtsTrue;
+	  gct->failed_to_evac = rtsTrue;
       }
   }
 
+  ws = &gct->steps[stp->gen_no][stp->no];
   bd->step = stp;
   bd->gen_no = stp->gen_no;
-  bd->link = stp->new_large_objects;
-  stp->new_large_objects = bd;
+  bd->link = ws->todo_large_objects;
+  ws->todo_large_objects = bd;
   bd->flags |= BF_EVACUATED;
 }
 
@@ -274,22 +342,22 @@ evacuate_large(StgPtr p)
    This is called (eventually) for every live object in the system.
 
    The caller to evacuate specifies a desired generation in the
-   evac_gen global variable.  The following conditions apply to
+   gct->evac_gen thread-lock variable.  The following conditions apply to
    evacuating an object which resides in generation M when we're
    collecting up to generation N
 
-   if  M >= evac_gen 
+   if  M >= gct->evac_gen 
            if  M > N     do nothing
 	   else          evac to step->to
 
-   if  M < evac_gen      evac to evac_gen, step 0
+   if  M < gct->evac_gen      evac to gct->evac_gen, step 0
 
    if the object is already evacuated, then we check which generation
    it now resides in.
 
-   if  M >= evac_gen     do nothing
-   if  M <  evac_gen     set failed_to_evac flag to indicate that we
-                         didn't manage to evacuate this object into evac_gen.
+   if  M >= gct->evac_gen     do nothing
+   if  M <  gct->evac_gen     set gct->failed_to_evac flag to indicate that we
+                         didn't manage to evacuate this object into gct->evac_gen.
 
 
    OPTIMISATION NOTES:
@@ -333,18 +401,26 @@ loop:
       switch (info->type) {
 
       case THUNK_STATIC:
-	  if (info->srt_bitmap != 0 && 
+	  if (info->srt_bitmap != 0 &&
 	      *THUNK_STATIC_LINK((StgClosure *)q) == NULL) {
-	      *THUNK_STATIC_LINK((StgClosure *)q) = static_objects;
-	      static_objects = (StgClosure *)q;
+	      ACQUIRE_SPIN_LOCK(&static_objects_sync);
+	      if (*THUNK_STATIC_LINK((StgClosure *)q) == NULL) {
+		  *THUNK_STATIC_LINK((StgClosure *)q) = static_objects;
+		  static_objects = (StgClosure *)q;
+	      }
+	      RELEASE_SPIN_LOCK(&static_objects_sync);
 	  }
 	  return q;
 	  
       case FUN_STATIC:
-	  if (info->srt_bitmap != 0 && 
+	  if (info->srt_bitmap != 0 &&
 	      *FUN_STATIC_LINK((StgClosure *)q) == NULL) {
-	      *FUN_STATIC_LINK((StgClosure *)q) = static_objects;
-	      static_objects = (StgClosure *)q;
+	      ACQUIRE_SPIN_LOCK(&static_objects_sync);
+	      if (*FUN_STATIC_LINK((StgClosure *)q) == NULL) {
+		  *FUN_STATIC_LINK((StgClosure *)q) = static_objects;
+		  static_objects = (StgClosure *)q;
+	      }
+	      RELEASE_SPIN_LOCK(&static_objects_sync);
 	  }
 	  return q;
 	  
@@ -353,17 +429,25 @@ loop:
 	   * on the CAF list, so don't do anything with it here (we'll
 	   * scavenge it later).
 	   */
-	  if (((StgIndStatic *)q)->saved_info == NULL
-	      && *IND_STATIC_LINK((StgClosure *)q) == NULL) {
-	      *IND_STATIC_LINK((StgClosure *)q) = static_objects;
-	      static_objects = (StgClosure *)q;
+	  if (((StgIndStatic *)q)->saved_info == NULL) {
+	      ACQUIRE_SPIN_LOCK(&static_objects_sync);
+	      if (*IND_STATIC_LINK((StgClosure *)q) == NULL) {
+		  *IND_STATIC_LINK((StgClosure *)q) = static_objects;
+		  static_objects = (StgClosure *)q;
+	      }
+	      RELEASE_SPIN_LOCK(&static_objects_sync);
 	  }
 	  return q;
 	  
       case CONSTR_STATIC:
 	  if (*STATIC_LINK(info,(StgClosure *)q) == NULL) {
-	      *STATIC_LINK(info,(StgClosure *)q) = static_objects;
-	      static_objects = (StgClosure *)q;
+	      ACQUIRE_SPIN_LOCK(&static_objects_sync);
+	      // re-test, after acquiring lock
+	      if (*STATIC_LINK(info,(StgClosure *)q) == NULL) {
+		  *STATIC_LINK(info,(StgClosure *)q) = static_objects;
+		  static_objects = (StgClosure *)q;
+	      }
+	      RELEASE_SPIN_LOCK(&static_objects_sync);
 	        /* I am assuming that static_objects pointers are not
 		 * written to other objects, and thus, no need to retag. */
 	  }
@@ -385,12 +469,12 @@ loop:
   if (bd->gen_no > N) {
       /* Can't evacuate this object, because it's in a generation
        * older than the ones we're collecting.  Let's hope that it's
-       * in evac_gen or older, or we will have to arrange to track
+       * in gct->evac_gen or older, or we will have to arrange to track
        * this pointer using the mutable list.
        */
-      if (bd->gen_no < evac_gen) {
+      if (bd->gen_no < gct->evac_gen) {
 	  // nope 
-	  failed_to_evac = rtsTrue;
+	  gct->failed_to_evac = rtsTrue;
 	  TICK_GC_FAILED_PROMOTION();
       }
       return TAG_CLOSURE(tag,q);
@@ -404,8 +488,8 @@ loop:
        * object twice, for example).
        */
       if (bd->flags & BF_EVACUATED) {
-	  if (bd->gen_no < evac_gen) {
-	      failed_to_evac = rtsTrue;
+	  if (bd->gen_no < gct->evac_gen) {
+	      gct->failed_to_evac = rtsTrue;
 	      TICK_GC_FAILED_PROMOTION();
 	  }
 	  return TAG_CLOSURE(tag,q);
@@ -446,9 +530,13 @@ loop:
   
   switch (info->type) {
 
+  case WHITEHOLE:
+      goto loop;
+
   case MUT_VAR_CLEAN:
   case MUT_VAR_DIRTY:
-  case MVAR:
+  case MVAR_CLEAN:
+  case MVAR_DIRTY:
       return copy(q,sizeW_fromITBL(info),stp);
 
   case CONSTR_0_1:
@@ -555,10 +643,10 @@ loop:
 
   case EVACUATED:
     /* Already evacuated, just return the forwarding address.
-     * HOWEVER: if the requested destination generation (evac_gen) is
+     * HOWEVER: if the requested destination generation (gct->evac_gen) is
      * older than the actual generation (because the object was
      * already evacuated to a younger generation) then we have to
-     * set the failed_to_evac flag to indicate that we couldn't 
+     * set the gct->failed_to_evac flag to indicate that we couldn't 
      * manage to promote the object to the desired generation.
      */
     /* 
@@ -570,10 +658,10 @@ loop:
      * current object would be evacuated to, so we only do the full
      * check if stp is too low.
      */
-    if (evac_gen > 0 && stp->gen_no < evac_gen) {  // optimisation 
+    if (gct->evac_gen > 0 && stp->gen_no < gct->evac_gen) {  // optimisation 
       StgClosure *p = ((StgEvacuated*)q)->evacuee;
-      if (HEAP_ALLOCED(p) && Bdescr((P_)p)->gen_no < evac_gen) {
-	failed_to_evac = rtsTrue;
+      if (HEAP_ALLOCED(p) && Bdescr((P_)p)->gen_no < gct->evac_gen) {
+	gct->failed_to_evac = rtsTrue;
 	TICK_GC_FAILED_PROMOTION();
       }
     }
@@ -713,18 +801,29 @@ selector_chain:
     info_ptr = p->header.info;
     field = get_itbl(p)->layout.selector_offset;
 
-    // If the THUNK_SELECTOR is in to-space or in a generation that we
-    // are not collecting, then bail out early.  We won't be able to
-    // save any space in any case, and updating with an indirection is
-    // trickier in an old gen.
     bd = Bdescr((StgPtr)p);
-    if (HEAP_ALLOCED(p) &&
-	((bd->gen_no > N)
-         || (bd->flags & BF_EVACUATED) 
-	 || ((bd->flags & BF_COMPACTED) &&
-	     is_marked((P_)p,bd)))) {
-        unchain_thunk_selectors(prev_thunk_selector, (StgClosure *)p);
-        return (StgClosure *)p;
+    if (HEAP_ALLOCED(p)) {
+        // If the THUNK_SELECTOR is in to-space or in a generation that we
+        // are not collecting, then bale out early.  We won't be able to
+        // save any space in any case, and updating with an indirection is
+        // trickier in a non-collected gen: we would have to update the
+        // mutable list.
+        if ((bd->gen_no > N) || (bd->flags & BF_EVACUATED)) {
+            unchain_thunk_selectors(prev_thunk_selector, (StgClosure *)p);
+            return (StgClosure *)p;
+        }
+        // we don't update THUNK_SELECTORS in the compacted
+        // generation, because compaction does not remove the INDs
+        // that result, this causes confusion later
+        // (scavenge_mark_stack doesn't deal with IND).  BEWARE!  This
+        // bit is very tricky to get right.  If you make changes
+        // around here, test by compiling stage 3 with +RTS -c -RTS.
+        if (bd->flags & BF_COMPACTED) {
+            // must call evacuate() to mark this closure if evac==rtsTrue
+            if (evac) p = (StgSelector *)evacuate((StgClosure *)p);
+            unchain_thunk_selectors(prev_thunk_selector, (StgClosure *)p);
+            return (StgClosure *)p;
+        }
     }
 
     // BLACKHOLE the selector thunk, since it is now under evaluation.
@@ -818,26 +917,18 @@ selector_loop:
       {
 	  StgClosure *val;
 
-	  // we don't update THUNK_SELECTORS in the compacted
-	  // generation, because compaction does not remove the INDs
-	  // that result, this causes confusion later
-	  // (scavenge_mark_stack doesn't deal with IND).
-	  if (Bdescr((P_)selectee)->flags && BF_COMPACTED) {
-	      goto bale_out;
-	  }
-
           // recursively evaluate this selector.  We don't want to
           // recurse indefinitely, so we impose a depth bound.
-	  if (thunk_selector_depth >= MAX_THUNK_SELECTOR_DEPTH) {
+	  if (gct->thunk_selector_depth >= MAX_THUNK_SELECTOR_DEPTH) {
 	      goto bale_out;
 	  }
 
-	  thunk_selector_depth++;
+	  gct->thunk_selector_depth++;
           // rtsFalse says "don't evacuate the result".  It will,
           // however, update any THUNK_SELECTORs that are evaluated
           // along the way.
 	  val = eval_thunk_selector((StgSelector *)selectee, rtsFalse);
-	  thunk_selector_depth--;
+	  gct->thunk_selector_depth--;
 
           // did we actually manage to evaluate it?
           if (val == selectee) goto bale_out;