Add mark function

1 files changed, 19 insertions, 0 deletions

diff --git a/runtime/src/gc.c b/runtime/src/gc.c
index b55dc03b..08c39cf9 100644
--- a/runtime/src/gc.c
+++ b/runtime/src/gc.c
@@ -4,6 +4,8 @@
 #include "./alloc.h"
 #include "./gc.h"
 
+// == Marking ==
+
 // The mark value for each object is initialized to 0. Each mark phase
 // alternates between using 0b010 and 0b100 as the mark value. We check only for
 // the bit set to 1, meaning static values can have a mark value of 0b110 to be
@@ -18,6 +20,22 @@ bool is_marked(struct ShedGcObjectHeader* object) {
     return (object->mark & current_mark_value) == current_mark_value;
 }
 
+void mark(struct ShedGcObjectHeader* object) {
+    if (is_marked(object)) {
+        return;
+    }
+
+    object->mark = current_mark_value;
+
+    struct ShedGcObjectHeader** children = (struct ShedGcObjectHeader**) (((void*) object) + object->children_offset);
+
+    for (size_t child_index = 0; child_index < object->children_count; child_index++) {
+        mark(children[child_index]);
+    }
+}
+
+// == Allocation ==
+
 struct ShedGcObjectHeader* first = NULL;
 
 void* shed__runtime__gc_alloc(size_t size, size_t children_offset, size_t children_count) {
@@ -31,3 +49,4 @@ void* shed__runtime__gc_alloc(size_t size, size_t children_offset, size_t childr
 
     return object;
 }
+