VM: visit_roots and visit_contexts where always called in tandem, make a new method visit_all_roots that calls them both

vm/aging_collector.cpp

@@ -38,9 +38,8 @@ void factor_vm::collect_aging() {
     copying_collector<aging_space, aging_policy> collector(this,
                                                            this->data->aging,
                                                            aging_policy(this));
-    collector.data_visitor.visit_roots();
-    collector.data_visitor.visit_contexts();
 
+    collector.visitor.visit_all_roots();
     collector.cheneys_algorithm();
 
     data->reset_nursery();

vm/callstack.hpp

@@ -44,10 +44,13 @@ template <typename Iterator, typename Fixup>
 void factor_vm::iterate_callstack(context* ctx, Iterator& iterator,
                                   Fixup& fixup) {
 
-  FACTOR_ASSERT(!Fixup::translated_code_block_map);
   cell top = ctx->callstack_top;
+  cell bottom = ctx->callstack_bottom;
+  /* When we are translating the code block maps, all callstacks must
+     be empty. */
+  FACTOR_ASSERT(!Fixup::translated_code_block_map || top == bottom);
 
-  while (top < ctx->callstack_bottom) {
+  while (top < bottom) {
     cell addr = *(cell*)top;
     FACTOR_ASSERT(addr != 0);
 
@@ -65,7 +68,7 @@ void factor_vm::iterate_callstack(context* ctx, Iterator& iterator,
     iterator(top, size, owner, addr);
     top += size;
   }
-  FACTOR_ASSERT(top == ctx->callstack_bottom);
+  FACTOR_ASSERT(top == bottom);
 }
 
 /* Allocates memory */

vm/compaction.cpp

@@ -211,8 +211,7 @@ void factor_vm::collect_compact_impl() {
       code->allocator->compact(code_block_updater, fixup, &code_finger);
     }
 
-    forwarder.visit_roots();
-    forwarder.visit_contexts();
+    forwarder.visit_all_roots();
     forwarder.visit_context_code_blocks();
   }
 

vm/full_collector.cpp

@@ -32,8 +32,7 @@ void factor_vm::collect_mark_impl() {
   code->allocator->state.clear_mark_bits();
   data->tenured->state.clear_mark_bits();
 
-  visitor.visit_roots();
-  visitor.visit_contexts();
+  visitor.visit_all_roots();
   visitor.visit_context_code_blocks();
   visitor.visit_uninitialized_code_blocks();
 

vm/image.cpp

@@ -117,8 +117,8 @@ struct start_object_updater {
 
 void factor_vm::fixup_data(cell data_offset, cell code_offset) {
   startup_fixup fixup(data_offset, code_offset);
-  slot_visitor<startup_fixup> data_workhorse(this, fixup);
-  data_workhorse.visit_roots();
+  slot_visitor<startup_fixup> visitor(this, fixup);
+  visitor.visit_all_roots();
 
   start_object_updater updater(this, fixup);
   data->tenured->iterate(updater, fixup);

vm/nursery_collector.cpp

@@ -9,9 +9,7 @@ void factor_vm::collect_nursery() {
                                                            this->data->aging,
                                                            nursery_policy(this));
 
-  collector.data_visitor.visit_roots();
-  collector.data_visitor.visit_contexts();
-
+  collector.visitor.visit_all_roots();
   gc_event* event = current_gc->event;
 
   if (event)

vm/objects.cpp

@@ -146,8 +146,7 @@ void factor_vm::primitive_become() {
   {
     slot_visitor<slot_become_fixup> workhorse(this,
                                               slot_become_fixup(&become_map));
-    workhorse.visit_roots();
-    workhorse.visit_contexts();
+    workhorse.visit_all_roots();
 
     object_become_visitor object_visitor(&workhorse);
     each_object(object_visitor);

vm/slot_visitor.hpp

@@ -101,9 +101,8 @@ them.
 This is used by GC's copying, sweep and compact phases, and the implementation
 of the become primitive.
 
-Iteration is driven by visit_*() methods. Some of them define GC roots:
-- visit_roots()
-- visit_contexts()
+Iteration is driven by visit_*() methods. Only one of them define GC roots:
+- visit_all_roots()
 
 Code block visitors iterate over sets of code blocks, applying a functor to
 each one. The functor returns a new code_block pointer, which may or may not
@@ -132,7 +131,7 @@ template <typename Fixup> struct slot_visitor {
   void visit_data_roots();
   void visit_callback_roots();
   void visit_literal_table_roots();
-  void visit_roots();
+  void visit_all_roots();
   void visit_callstack_object(callstack* stack);
   void visit_callstack(context* ctx);
   void visit_context(context *ctx);
@@ -242,7 +241,7 @@ template <typename Fixup> void slot_visitor<Fixup>::visit_sample_threads() {
   }
 }
 
-template <typename Fixup> void slot_visitor<Fixup>::visit_roots() {
+template <typename Fixup> void slot_visitor<Fixup>::visit_all_roots() {
   visit_handle(&parent->true_object);
   visit_handle(&parent->bignum_zero);
   visit_handle(&parent->bignum_pos_one);
@@ -256,6 +255,9 @@ template <typename Fixup> void slot_visitor<Fixup>::visit_roots() {
 
   visit_object_array(parent->special_objects,
                      parent->special_objects + special_object_count);
+
+
+  visit_contexts();
 }
 
 /* primitive_minor_gc() is invoked by inline GC checks, and it needs to fill in

vm/to_tenured_collector.cpp

@@ -22,9 +22,7 @@ void factor_vm::collect_to_tenured() {
 
   mark_stack.clear();
 
-  collector.data_visitor.visit_roots();
-  collector.data_visitor.visit_contexts();
-
+  collector.visitor.visit_all_roots();
   gc_event* event = current_gc->event;
 
   if (event)