various memory cleanup cleanups

src/6model/reprs/MVMArray.c

@@ -92,10 +92,7 @@ static void gc_mark(MVMThreadContext *tc, MVMSTable *st, void *data, MVMGCWorkli
 /* Called by the VM in order to free memory associated with this object. */
 static void gc_free(MVMThreadContext *tc, MVMObject *obj) {
     MVMArray *arr = (MVMArray *)obj;
-    if (arr->body.slots.any) {
-        free(arr->body.slots.any);
-        arr->body.slots.any = NULL;
-    }
+    MVM_checked_free_null(arr->body.slots.any);
 }
 
 /* Gets the storage specification for this representation. */

src/6model/reprs/MVMCallCapture.c

@@ -62,12 +62,8 @@ static void gc_free(MVMThreadContext *tc, MVMObject *obj) {
         /* We made our own copy of the args buffer and processing context, so
          * free them both. */
         if (ctx->body.apc) {
-            if (ctx->body.apc->args) {
-                free(ctx->body.apc->args);
-                ctx->body.apc->args = NULL;
-            }
-            free(ctx->body.apc);
-            ctx->body.apc = NULL;
+            MVM_checked_free_null(ctx->body.apc->args);
+            MVM_checked_free_null(ctx->body.apc);
         }
     }
 }

src/6model/reprs/MVMString.c

@@ -75,9 +75,7 @@ static void gc_mark(MVMThreadContext *tc, MVMSTable *st, void *data, MVMGCWorkli
 /* Called by the VM in order to free memory associated with this object. */
 static void gc_free(MVMThreadContext *tc, MVMObject *obj) {
     MVMString *str = (MVMString *)obj;
-    if (str->body.storage)
-        free(str->body.storage);
-    str->body.storage = NULL;
+    MVM_checked_free_null(str->body.storage);
     str->body.graphs = str->body.codes = str->body.flags = 0;
 }
 

src/6model/reprs/NFA.c

@@ -57,10 +57,10 @@ static void gc_free(MVMThreadContext *tc, MVMObject *obj) {
     MVMNFA *nfa = (MVMNFA *)obj;
     MVMint64 i;
     for (i = 0; i < nfa->body.num_states; i++)
-        if (nfa->body.states[i])
-            free(nfa->body.states[i]);
-    free(nfa->body.states);
-    free(nfa->body.num_state_edges);
+        if (nfa->body.num_state_edges[i])
+            MVM_checked_free_null(nfa->body.states[i]);
+    MVM_checked_free_null(nfa->body.states);
+    MVM_checked_free_null(nfa->body.num_state_edges);
 }
 
 /* Gets the storage specification for this representation. */

src/6model/reprs/P6opaque.c

@@ -977,7 +977,8 @@ void change_type(MVMThreadContext *tc, MVMObject *obj, MVMObject *new_type) {
         /* Allocate new memory. */
         size_t  new_size = STABLE(new_type)->size - sizeof(MVMObject);
         void   *new = malloc(new_size);
-        memset(new, 0, new_size);
+        memset((char *)new + (STABLE(obj)->size - sizeof(MVMObject)),
+            0, new_size - (STABLE(obj)->size - sizeof(MVMObject)));
 
         /* Copy existing to new.
          * XXX Need more care here, as may have to re-barrier pointers. */

src/6model/reprs/SCRef.c

@@ -63,8 +63,6 @@ static void gc_mark(MVMThreadContext *tc, MVMSTable *st, void *data, MVMGCWorkli
     for (i = 0; i < sc->num_stables; i++)
         MVM_gc_worklist_add(tc, worklist, &sc->root_stables[i]);
 
-    /* Maintain backlink (yes, this is ugly). */
-    sc->sc = (MVMSerializationContext *)((char *)data - sizeof(MVMObject));
     MVM_gc_worklist_add(tc, worklist, &sc->sc);
 }
 
@@ -79,7 +77,7 @@ static void gc_free(MVMThreadContext *tc, MVMObject *obj) {
 
     /* Free manually managed STable list memory and body. */
     MVM_checked_free_null(sc->body->root_stables);
-    free(sc->body);
+    MVM_checked_free_null(sc->body);
 }
 
 /* Gets the storage specification for this representation. */

src/gc/collect.c

@@ -513,7 +513,7 @@ void MVM_gc_collect_free_nursery_uncopied(MVMThreadContext *tc, void *limit) {
             /* Object instance. If dead, call gc_free if needed. Scan is
              * incremented by object size. */
             MVMObject *obj = (MVMObject *)item;
-/*            GCCOLL_LOG(tc, "Thread %d run %d : collecting an object %d in the nursery\n", item);*/
+            GCCOLL_LOG(tc, "Thread %d run %d : collecting an object %d in the nursery with reprid %d\n", item, REPR(obj)->ID);
             if (dead && REPR(obj)->gc_free)
                 REPR(obj)->gc_free(tc, obj);
         }
@@ -609,7 +609,7 @@ void MVM_gc_collect_free_gen2_unmarked(MVMThreadContext *tc) {
                     }
                     else if (col->flags & MVM_CF_STABLE) {
                         if (col->sc == (MVMSerializationContext *)1) {
-                            /* we marked it dead last time, kill it. */
+                            /* We marked it dead last time, kill it. */
                             MVM_6model_stable_gc_free(tc, (MVMSTable *)col);
                         }
                         else {
@@ -621,7 +621,8 @@ void MVM_gc_collect_free_gen2_unmarked(MVMThreadContext *tc) {
                                 /* There will definitely be another gc run, so mark it as "died last time". */
                                 col->sc = (MVMSerializationContext *)1;
                             }
-                            goto skip_freelist_update;
+                            /* Skip the freelist updating. */
+                            continue;
                         }
                     }
                     else {
@@ -635,7 +636,6 @@ void MVM_gc_collect_free_gen2_unmarked(MVMThreadContext *tc) {
 
                     /* Update the pointer to the insert position to point to us */
                     freelist_insert_pos = (char ***)cur_ptr;
-                    skip_freelist_update: ;
                 }
 
                 /* Move to the next object. */

src/moarvm.c

@@ -150,7 +150,7 @@ void MVM_vm_destroy_instance(MVMInstance *instance) {
 
     /* Run the GC global destruction phase. After this,
      * no 6model object pointers should be accessed. */
-    //MVM_gc_global_destruction(instance->main_thread);
+    MVM_gc_global_destruction(instance->main_thread);
 
     /* Free various instance-wide storage. */
     MVM_checked_free_null(instance->boot_types);