VM: get rid of the duplicated nursery instance in vm->data->nursery

vm.nursery and vm->data->nursery are different objects. They get out
of sync when Factor code bumps vm.nursery but leaves vm->data->nursery
unchanged. The emptiness of vm->data->nursery meant that each_object()
never iterated it.

vm/allot.hpp

@@ -8,14 +8,15 @@ namespace factor {
 inline object* factor_vm::allot_object(cell type, cell size) {
   FACTOR_ASSERT(!current_gc);
 
+  nursery_space *nursery = data->nursery;
   /* If the object is smaller than the nursery, allocate it in the nursery,
      after a GC if needed */
-  if (nursery.size > size) {
+  if (nursery->size > size) {
     /* If there is insufficient room, collect the nursery */
-    if (nursery.here + size > nursery.end)
+    if (nursery->here + size > nursery->end)
       primitive_minor_gc();
 
-    object* obj = nursery.allot(size);
+    object* obj = nursery->allot(size);
 
     obj->initialize(type);
     return obj;

vm/compaction.cpp

@@ -328,7 +328,7 @@ void factor_vm::collect_growing_heap(cell requested_size,
                                      bool trace_contexts_p) {
   /* Grow the data heap and copy all live objects to the new heap. */
   data_heap* old = data;
-  set_data_heap(data->grow(requested_size));
+  set_data_heap(data->grow(&nursery, requested_size));
   collect_mark_impl(trace_contexts_p);
   collect_compact_code_impl(trace_contexts_p);
   code->flush_icache();

vm/data_heap.cpp

@@ -7,7 +7,11 @@ void factor_vm::init_card_decks() {
   decks_offset = (cell)data->decks - addr_to_deck(data->start);
 }
 
-data_heap::data_heap(cell young_size_, cell aging_size_, cell tenured_size_) {
+data_heap::data_heap(nursery_space* vm_nursery,
+                     cell young_size_,
+                     cell aging_size_,
+                     cell tenured_size_) {
+
   young_size_ = align(young_size_, deck_size);
   aging_size_ = align(aging_size_, deck_size);
   tenured_size_ = align(tenured_size_, deck_size);
@@ -36,14 +40,18 @@ data_heap::data_heap(cell young_size_, cell aging_size_, cell tenured_size_) {
   aging = new aging_space(aging_size, tenured->end);
   aging_semispace = new aging_space(aging_size, aging->end);
 
-  nursery = new nursery_space(young_size, aging_semispace->end);
+  // Initialize vm nursery
+  vm_nursery->here = aging_semispace->end;
+  vm_nursery->start = aging_semispace->end;
+  vm_nursery->end = vm_nursery->start + young_size;
+  vm_nursery->size = young_size;
+  nursery = vm_nursery;
 
   FACTOR_ASSERT(seg->end - nursery->end <= deck_size);
 }
 
 data_heap::~data_heap() {
   delete seg;
-  delete nursery;
   delete aging;
   delete aging_semispace;
   delete tenured;
@@ -51,9 +59,10 @@ data_heap::~data_heap() {
   delete[] decks;
 }
 
-data_heap* data_heap::grow(cell requested_bytes) {
+data_heap* data_heap::grow(nursery_space* vm_nursery, cell requested_bytes) {
+  FACTOR_ASSERT(vm_nursery->occupied_space() == 0);
   cell new_tenured_size = (tenured_size * 2) + requested_bytes;
-  return new data_heap(young_size, aging_size, new_tenured_size);
+  return new data_heap(vm_nursery, young_size, aging_size, new_tenured_size);
 }
 
 template <typename Generation> void data_heap::clear_cards(Generation* gen) {
@@ -99,21 +108,20 @@ void data_heap::mark_all_cards() {
 
 void factor_vm::set_data_heap(data_heap* data_) {
   data = data_;
-  nursery = *data->nursery;
   init_card_decks();
 }
 
 void factor_vm::init_data_heap(cell young_size, cell aging_size,
                                cell tenured_size) {
-  set_data_heap(new data_heap(young_size, aging_size, tenured_size));
+  set_data_heap(new data_heap(&nursery, young_size, aging_size, tenured_size));
 }
 
 data_heap_room factor_vm::data_room() {
   data_heap_room room;
 
-  room.nursery_size = nursery.size;
-  room.nursery_occupied = nursery.occupied_space();
-  room.nursery_free = nursery.free_space();
+  room.nursery_size = data->nursery->size;
+  room.nursery_occupied = data->nursery->occupied_space();
+  room.nursery_free = data->nursery->free_space();
   room.aging_size = data->aging->size;
   room.aging_occupied = data->aging->occupied_space();
   room.aging_free = data->aging->free_space();

vm/data_heap.hpp

@@ -9,6 +9,7 @@ struct data_heap {
 
   segment* seg;
 
+  /* Borrowed reference to a factor_vm::nursery */
   nursery_space* nursery;
   aging_space* aging;
   aging_space* aging_semispace;
@@ -20,9 +21,12 @@ struct data_heap {
   card_deck* decks;
   card_deck* decks_end;
 
-  data_heap(cell young_size, cell aging_size, cell tenured_size);
+  data_heap(nursery_space* vm_nursery,
+            cell young_size,
+            cell aging_size,
+            cell tenured_size);
   ~data_heap();
-  data_heap* grow(cell requested_size);
+  data_heap* grow(nursery_space* vm_nursery, cell requested_size);
   template <typename Generation> void clear_cards(Generation* gen);
   template <typename Generation> void clear_decks(Generation* gen);
   void reset_generation(nursery_space* gen);

vm/generic_arrays.hpp

@@ -23,7 +23,8 @@ Array* factor_vm::allot_uninitialized_array(cell capacity) {
 
 template <typename Array>
 bool factor_vm::reallot_array_in_place_p(Array* array, cell capacity) {
-  return nursery.contains_p(array) && capacity <= array_capacity(array);
+  return data->nursery->contains_p(array) &&
+      capacity <= array_capacity(array);
 }
 
 /* Allocates memory (sometimes) */

vm/nursery_collector.hpp

@@ -5,7 +5,9 @@ struct nursery_policy {
 
   explicit nursery_policy(factor_vm* parent) : parent(parent) {}
 
-  bool should_copy_p(object* obj) { return parent->nursery.contains_p(obj); }
+  bool should_copy_p(object* obj) {
+    return parent->data->nursery->contains_p(obj);
+  }
 
   void promoted_object(object* obj) {}
 

vm/strings.cpp

@@ -54,9 +54,9 @@ void factor_vm::primitive_string() {
 }
 
 bool factor_vm::reallot_string_in_place_p(string* str, cell capacity) {
-  return nursery.contains_p(str) &&
+  return data->nursery->contains_p(str) &&
          (!to_boolean(str->aux) ||
-          nursery.contains_p(untag<byte_array>(str->aux))) &&
+          data->nursery->contains_p(untag<byte_array>(str->aux))) &&
          capacity <= string_capacity(str);
 }
 

vm/vm.hpp

@@ -16,7 +16,8 @@ struct factor_vm {
   /* Spare context -- for callbacks */
   context* spare_ctx;
 
-  /* New objects are allocated here */
+  /* New objects are allocated here, use the data->nursery reference
+     instead from c++ code. */
   nursery_space nursery;
 
   /* Add this to a shifted address to compute write barrier offsets */
@@ -331,7 +332,7 @@ struct factor_vm {
     /* The nursery can't be iterated because there may be gaps between
        the objects (see factor_vm::reallot_array) so we require it to
        be empty first. */
-    FACTOR_ASSERT(nursery.occupied_space() == 0);
+    FACTOR_ASSERT(data->nursery->occupied_space() == 0);
 
     gc_off = true;
     each_object(data->tenured, iterator);