vm: fix issue with unnecessary heap growth

vm/code_block.cpp

@@ -127,9 +127,8 @@ void *factor_vm::get_rel_symbol(array *literals, cell index)
 		}
 	case ARRAY_TYPE:
 		{
-			cell i;
 			array *names = untag<array>(symbol);
-			for(i = 0; i < array_capacity(names); i++)
+			for(cell i = 0; i < array_capacity(names); i++)
 			{
 				symbol_char *name = alien_offset(array_nth(names,i));
 				void *sym = ffi_dlsym(d,name);

vm/data_heap.cpp

@@ -98,6 +98,11 @@ void data_heap::reset_generation(tenured_space *gen)
 	clear_decks(gen);
 }
 
+bool data_heap::low_memory_p()
+{
+	return (tenured->free_space() <= nursery->size + aging->size);
+}
+
 void factor_vm::set_data_heap(data_heap *data_)
 {
 	data = data_;

vm/data_heap.hpp

@@ -29,6 +29,7 @@ struct data_heap {
 	void reset_generation(nursery_space *gen);
 	void reset_generation(aging_space *gen);
 	void reset_generation(tenured_space *gen);
+	bool low_memory_p();
 };
 
 struct data_heap_room {

vm/full_collector.cpp

@@ -118,6 +118,22 @@ void factor_vm::collect_sweep_impl()
 	current_gc->event->ended_data_sweep();
 }
 
+void factor_vm::collect_full(bool trace_contexts_p)
+{
+	collect_mark_impl(trace_contexts_p);
+	collect_sweep_impl();
+	if(data->tenured->largest_free_block() <= data->nursery->size + data->aging->size)
+		collect_compact_impl(trace_contexts_p);
+	else
+		update_code_heap_words_and_literals();
+}
+
+void factor_vm::collect_compact(bool trace_contexts_p)
+{
+	collect_mark_impl(trace_contexts_p);
+	collect_compact_impl(trace_contexts_p);
+}
+
 void factor_vm::collect_growing_heap(cell requested_bytes, bool trace_contexts_p)
 {
 	/* Grow the data heap and copy all live objects to the new heap. */

vm/gc.cpp

@@ -152,12 +152,6 @@ void factor_vm::gc(gc_op op, cell requested_bytes, bool trace_contexts_p)
 		start_gc_again();
 	}
 
-	if(current_gc->op == collect_aging_op || current_gc->op == collect_to_tenured_op)
-	{
-		if(data->tenured->free_space() <= data->nursery->size + data->aging->size)
-			current_gc->op = collect_full_op;
-	}
-
 	current_gc->event->op = current_gc->op;
 
 	switch(current_gc->op)
@@ -167,21 +161,27 @@ void factor_vm::gc(gc_op op, cell requested_bytes, bool trace_contexts_p)
 		break;
 	case collect_aging_op:
 		collect_aging();
+		if(data->low_memory_p())
+		{
+			current_gc->op = collect_full_op;
+			current_gc->event->op = collect_full_op;
+			collect_full(trace_contexts_p);
+		}
 		break;
 	case collect_to_tenured_op:
 		collect_to_tenured();
+		if(data->low_memory_p())
+		{
+			current_gc->op = collect_full_op;
+			current_gc->event->op = collect_full_op;
+			collect_full(trace_contexts_p);
+		}
 		break;
 	case collect_full_op:
-		collect_mark_impl(trace_contexts_p);
+		collect_full(trace_contexts_p);
-		collect_sweep_impl();
-		if(data->tenured->largest_free_block() <= data->nursery->size + data->aging->size)
-			collect_compact_impl(trace_contexts_p);
-		else
-			update_code_heap_words_and_literals();
 		break;
 	case collect_compact_op:
-		collect_mark_impl(trace_contexts_p);
+		collect_compact(trace_contexts_p);
-		collect_compact_impl(trace_contexts_p);
 		break;
 	case collect_growing_heap_op:
 		collect_growing_heap(requested_bytes,trace_contexts_p);

vm/vm.hpp

@@ -262,8 +262,10 @@ struct factor_vm
 	void update_code_roots_for_compaction();
 	void collect_mark_impl(bool trace_contexts_p);
 	void collect_sweep_impl();
+	void collect_full(bool trace_contexts_p);
 	void collect_compact_impl(bool trace_contexts_p);
 	void collect_compact_code_impl(bool trace_contexts_p);
+	void collect_compact(bool trace_contexts_p);
 	void collect_growing_heap(cell requested_bytes, bool trace_contexts_p);
 	void gc(gc_op op, cell requested_bytes, bool trace_contexts_p);
 	void primitive_minor_gc();