vm: debugging mark-sweep

vm/aging_collector.cpp

@@ -40,9 +40,10 @@ void factor_vm::collect_aging()
 		collector.trace_contexts();
 		collector.trace_code_heap_roots(&code->points_to_aging);
 		collector.cheneys_algorithm();
+
 		update_code_heap_for_minor_gc(&code->points_to_aging);
 
-		nursery.here = nursery.start;
+		data->reset_generation(&nursery);
 		code->points_to_nursery.clear();
 	}
 }

vm/data_heap.cpp

@@ -65,11 +65,43 @@ data_heap *data_heap::grow(cell requested_bytes)
 	return new data_heap(young_size,aging_size,new_tenured_size);
 }
 
+template<typename Generation> void data_heap::clear_cards(Generation *gen)
+{
+	cell first_card = addr_to_card(gen->start - start);
+	cell last_card = addr_to_card(gen->end - start);
+	memset(&cards[first_card],0,last_card - first_card);
+}
+
+template<typename Generation> void data_heap::clear_decks(Generation *gen)
+{
+	cell first_deck = addr_to_deck(gen->start - start);
+	cell last_deck = addr_to_deck(gen->end - start);
+	memset(&decks[first_deck],0,last_deck - first_deck);
+}
+
+void data_heap::reset_generation(nursery_space *gen)
+{
+	gen->here = gen->start;
+}
+
+void data_heap::reset_generation(aging_space *gen)
+{
+	gen->here = gen->start;
+	clear_cards(gen);
+	clear_decks(gen);
+	gen->starts.clear_object_start_offsets();
+}
+
+void data_heap::reset_generation(tenured_space *gen)
+{
+	clear_cards(gen);
+	clear_decks(gen);
+}
+
 void factor_vm::set_data_heap(data_heap *data_)
 {
 	data = data_;
 	nursery = *data->nursery;
-	nursery.here = nursery.start;
 	init_card_decks();
 }
 

vm/data_heap.hpp

@@ -26,31 +26,9 @@ struct data_heap {
 	data_heap *grow(cell requested_size);
 	template<typename Generation> void clear_cards(Generation *gen);
 	template<typename Generation> void clear_decks(Generation *gen);
-	template<typename Generation> void reset_generation(Generation *gen);
+	void reset_generation(nursery_space *gen);
+	void reset_generation(aging_space *gen);
+	void reset_generation(tenured_space *gen);
 };
 
-template<typename Generation> void data_heap::clear_cards(Generation *gen)
-{
-	cell first_card = addr_to_card(gen->start - start);
-	cell last_card = addr_to_card(gen->end - start);
-	memset(&cards[first_card],0,last_card - first_card);
-}
-
-template<typename Generation> void data_heap::clear_decks(Generation *gen)
-{
-	cell first_deck = addr_to_deck(gen->start - start);
-	cell last_deck = addr_to_deck(gen->end - start);
-	memset(&decks[first_deck],0,last_deck - first_deck);
-}
-
-/* After garbage collection, any generations which are now empty need to have
-their allocation pointers and cards reset. */
-template<typename Generation> void data_heap::reset_generation(Generation *gen)
-{
-	gen->here = gen->start;
-	clear_cards(gen);
-	clear_decks(gen);
-	gen->starts.clear_object_start_offsets();
-}
-
 }

vm/free_list_allocator.hpp

@@ -88,10 +88,12 @@ Makes a free list consisting of one free block, at the very end. */
 template<typename Block> void free_list_allocator<Block>::build_free_list(cell size)
 {
 	clear_free_list();
+	if(size != this->size)
+	{
 		free_heap_block *last_block = (free_heap_block *)(start + size);
-	last_block->set_free();
+		last_block->make_free(end - (cell)last_block);
-	last_block->set_size(end - (cell)last_block);
 		add_to_free_list(last_block);
+	}
 }
 
 template<typename Block> void free_list_allocator<Block>::assert_free_block(free_heap_block *block)
@@ -147,10 +149,9 @@ template<typename Block> free_heap_block *free_list_allocator<Block>::split_free
 	{
 		/* split the block in two */
 		free_heap_block *split = (free_heap_block *)((cell)block + size);
-		split->set_free();
+		split->make_free(block->size() - size);
-		split->set_size(block->size() - size);
 		split->next_free = block->next_free;
-		block->set_size(size);
+		block->make_free(size);
 		add_to_free_list(split);
 	}
 
@@ -174,7 +175,7 @@ template<typename Block> Block *free_list_allocator<Block>::allot(cell size)
 template<typename Block> void free_list_allocator<Block>::free(Block *block)
 {
 	free_heap_block *free_block = (free_heap_block *)block;
-	free_block->set_free();
+	free_block->make_free(block->size());
 	add_to_free_list(free_block);
 }
 
@@ -267,7 +268,8 @@ void free_list_allocator<Block>::sweep()
 			}
 			else
 			{
-				((free_heap_block *)scan)->set_free();
+				free_heap_block *free_block = (free_heap_block *)scan;
+				free_block->make_free(size);
 				prev = scan;
 			}
 		}
@@ -319,7 +321,8 @@ void free_list_allocator<Block>::sweep(Iterator &iter)
 			}
 			else
 			{
-				scan->set_free();
+				free_heap_block *free_block = (free_heap_block *)scan;
+				free_block->make_free(size);
 				prev = scan;
 			}
 		}

vm/full_collector.cpp

@@ -108,12 +108,24 @@ void full_collector::mark_reachable_objects()
 	}
 }
 
+struct object_start_map_updater {
+	object_start_map *starts;
+
+	object_start_map_updater(object_start_map *starts_) : starts(starts_) {}
+
+	void operator()(object *obj, cell size)
+	{
+		starts->record_object_start_offset(obj);
+	}
+};
+
 void factor_vm::collect_full_impl(bool trace_contexts_p)
 {
 	full_collector collector(this);
 
 	code->clear_mark_bits();
 	data->tenured->clear_mark_bits();
+	data->tenured->clear_mark_stack();
 
 	collector.trace_roots();
         if(trace_contexts_p)
@@ -125,9 +137,14 @@ void factor_vm::collect_full_impl(bool trace_contexts_p)
 
 	collector.mark_reachable_objects();
 
-	data->tenured->sweep();
+	data->tenured->starts.clear_object_start_offsets();
+	object_start_map_updater updater(&data->tenured->starts);
+	data->tenured->sweep(updater);
+
+	data->reset_generation(data->tenured);
 	data->reset_generation(data->aging);
-	nursery.here = nursery.start;
+	data->reset_generation(&nursery);
+	code->clear_remembered_set();
 }
 
 void factor_vm::collect_growing_heap(cell requested_bytes,
@@ -144,8 +161,6 @@ void factor_vm::collect_growing_heap(cell requested_bytes,
 		compact_code_heap(trace_contexts_p);
 	else
 		relocate_code_heap();
-
-	code->clear_remembered_set();
 }
 
 void factor_vm::collect_full(bool trace_contexts_p, bool compact_code_heap_p)
@@ -156,8 +171,6 @@ void factor_vm::collect_full(bool trace_contexts_p, bool compact_code_heap_p)
 		compact_code_heap(trace_contexts_p);
 	else
 		update_code_heap_words_and_literals();
-
-	code->clear_remembered_set();
 }
 
 }

vm/layouts.hpp

@@ -58,8 +58,6 @@ static const cell data_alignment = 16;
 
 #define TYPE_COUNT 15
 
-/* Not real types, but code_block's type can be set to this */
-
 enum code_block_type
 {
 	code_block_unoptimized,
@@ -229,30 +227,29 @@ struct heap_block
 		return header & 1 == 1;
 	}
 
-	void set_free()
-	{
-		header |= 1;
-	}
-
-	void clear_free()
-	{
-		header &= ~1;
-	}
-
 	cell size()
 	{
-		return header >> 3;
+		cell bytes = header >> 3;
+#ifdef FACTOR_DEBUG
+		assert(bytes > 0);
+#endif
+		return bytes;
 	}
 
 	void set_size(cell size)
 	{
-		header = (header & 0x7) | (size << 3);
+		header = ((header & 0x7) | (size << 3));
 	}
 };
 
 struct free_heap_block : public heap_block
 {
 	free_heap_block *next_free;
+
+	void make_free(cell size)
+	{
+		header = (size << 3) | 1;
+	}
 };
 
 struct code_block : public heap_block

vm/mark_bits.hpp

@@ -55,11 +55,6 @@ template<typename Block> struct mark_bits {
 		cell line_number = block_line(address);
 		cell word_index = (line_number >> 6);
 		cell word_shift = (line_number & 63);
-
-#ifdef FACTOR_DEBUG
-		assert(word_index < bits_size);
-#endif
-
 		return std::make_pair(word_index,word_shift);
 	}
 

vm/nursery_collector.cpp

@@ -28,7 +28,7 @@ void factor_vm::collect_nursery()
 	collector.cheneys_algorithm();
 	update_code_heap_for_minor_gc(&code->points_to_nursery);
 
-	nursery.here = nursery.start;
+	data->reset_generation(&nursery);
 	code->points_to_nursery.clear();
 }
 

vm/tenured_space.hpp

@@ -51,6 +51,11 @@ struct tenured_space : free_list_allocator<object> {
 		state.clear_mark_bits();
 	}
 
+	void clear_mark_stack()
+	{
+		mark_stack.clear();
+	}
+
 	bool marked_p(object *obj)
 	{
 		return this->state.marked_p(obj);

vm/to_tenured_collector.cpp

@@ -26,19 +26,20 @@ void factor_vm::collect_to_tenured()
 	/* Copy live objects from aging space to tenured space. */
 	to_tenured_collector collector(this);
 
+	data->tenured->clear_mark_stack();
+
 	collector.trace_roots();
 	collector.trace_contexts();
 	collector.trace_cards(data->tenured,
 		card_points_to_aging,
-		dummy_unmarker());
+		simple_unmarker(card_mark_mask));
 	collector.trace_code_heap_roots(&code->points_to_aging);
 	collector.tenure_reachable_objects();
 	update_code_heap_for_minor_gc(&code->points_to_aging);
 
-	nursery.here = nursery.start;
+	data->reset_generation(&nursery);
 	data->reset_generation(data->aging);
-	code->points_to_nursery.clear();
+	code->clear_remembered_set();
-	code->points_to_aging.clear();
 }
 
 }