From 812d7c7992a09c1ef0fec9c00108540462d06211 Mon Sep 17 00:00:00 2001
From: Michael Williamson <mike@zwobble.org>
Date: Tue, 19 Mar 2024 16:34:27 +0000
Subject: Extract common GC code

---
 runtime/src/shed/gc.c                   | 42 ++++++++++++++++++++++++++++++++
 runtime/src/shed/gc.h                   | 32 +++++++++++++++++++-----
 runtime/src/shed/gc/mark-and-sweep/gc.c | 43 ++-------------------------------
 3 files changed, 70 insertions(+), 47 deletions(-)
 create mode 100644 runtime/src/shed/gc.c

(limited to 'runtime/src')

diff --git a/runtime/src/shed/gc.c b/runtime/src/shed/gc.c
new file mode 100644
index 00000000..b11b2bd7
--- /dev/null
+++ b/runtime/src/shed/gc.c
@@ -0,0 +1,42 @@
+#include <stdbool.h>
+
+#include "./gc.h"
+#include "./primitives.h"
+#include "./std/unistd.h"
+
+// == GC objects ==
+
+bool shed__runtime__gc_is_gc_object(ShedObject object) {
+    // Check that the object is not one of:
+    // * unit (0)
+    // * false (0)
+    // * true (1)
+    return !(object == 0 || object == 1);
+}
+
+// == Roots ==
+
+ShedGcRootIndex shed__runtime__gc_root_stack_index = 0;
+
+struct ShedGcObjectHeader* shed__runtime__gc_root_stack[16384];
+
+ShedGcRootIndex shed__runtime__gc_get_root_stack_index() {
+    return shed__runtime__gc_root_stack_index;
+}
+
+void shed__runtime__gc_set_root_stack_index(ShedGcRootIndex new_shed__runtime__gc_root_stack_index) {
+    shed__runtime__gc_root_stack_index = new_shed__runtime__gc_root_stack_index;
+}
+
+void shed__runtime__gc_push_root_gc_object(struct ShedGcObjectHeader* gc_root) {
+    shed__runtime__gc_root_stack[shed__runtime__gc_root_stack_index] = gc_root;
+    shed__runtime__gc_root_stack_index++;
+}
+
+void shed__runtime__gc_push_root(ShedObject gc_root) {
+    if (!shed__runtime__gc_is_gc_object(gc_root)) {
+        return;
+    }
+
+    shed__runtime__gc_push_root_gc_object((struct ShedGcObjectHeader*) gc_root);
+}
diff --git a/runtime/src/shed/gc.h b/runtime/src/shed/gc.h
index 9e39e7b7..ba1c98a4 100644
--- a/runtime/src/shed/gc.h
+++ b/runtime/src/shed/gc.h
@@ -1,15 +1,13 @@
 #ifndef SHED_GC_H
 #define SHED_GC_H
 
-#include "./std/unistd.h"
+#include <stdbool.h>
 
 #include "../patio/patio.h"
+#include "./std/unistd.h"
+#include "./primitives.h"
 
-struct ShedGcObjectHeader {
-    struct ShedGcObjectHeader* next;
-    uint32_t mark;
-    uint32_t runtime_type_tag;
-};
+// == Runtime types ==
 
 struct RuntimeType {
     uint32_t children_offset;
@@ -18,6 +16,28 @@ struct RuntimeType {
 
 extern struct RuntimeType shed__rtti[];
 
+// == GC objects ==
+
+struct ShedGcObjectHeader {
+    struct ShedGcObjectHeader* next;
+    uint32_t mark;
+    uint32_t runtime_type_tag;
+};
+
+bool shed__runtime__gc_is_gc_object(ShedObject object);
+
+// == Roots ==
+
+typedef size_t ShedGcRootIndex;
+
+extern ShedGcRootIndex shed__runtime__gc_root_stack_index;
+
+extern struct ShedGcObjectHeader* shed__runtime__gc_root_stack[];
+
+void shed__runtime__gc_push_root_gc_object(struct ShedGcObjectHeader* gc_root);
+
+// == Allocation ==
+
 void* shed__runtime__gc_alloc(size_t size, uint32_t runtime_type_tag);
 
 #endif
diff --git a/runtime/src/shed/gc/mark-and-sweep/gc.c b/runtime/src/shed/gc/mark-and-sweep/gc.c
index e6cbc0fa..40ffa98b 100644
--- a/runtime/src/shed/gc/mark-and-sweep/gc.c
+++ b/runtime/src/shed/gc/mark-and-sweep/gc.c
@@ -5,16 +5,6 @@
 #include "../../primitives.h"
 #include "../../std/malloc.h"
 
-// == GC objects ==
-
-bool is_gc_object(ShedObject object) {
-    // Check that the object is not one of:
-    // * unit (0)
-    // * false (0)
-    // * true (1)
-    return !(object == 0 || object == 1);
-}
-
 // == Marking ==
 
 // The mark value for each object is initialized to 0. Each mark phase
@@ -49,35 +39,6 @@ void mark(struct ShedGcObjectHeader* object) {
     }
 }
 
-// == Roots ==
-
-typedef size_t ShedGcRootIndex;
-
-ShedGcRootIndex gc_root_stack_index = 0;
-
-struct ShedGcObjectHeader* gc_root_stack[16384];
-
-ShedGcRootIndex shed__runtime__gc_get_root_stack_index() {
-    return gc_root_stack_index;
-}
-
-void shed__runtime__gc_set_root_stack_index(ShedGcRootIndex new_gc_root_stack_index) {
-    gc_root_stack_index = new_gc_root_stack_index;
-}
-
-static void shed__runtime__gc_push_root_gc_object(struct ShedGcObjectHeader* gc_root) {
-    gc_root_stack[gc_root_stack_index] = gc_root;
-    gc_root_stack_index++;
-}
-
-void shed__runtime__gc_push_root(ShedObject gc_root) {
-    if (!is_gc_object(gc_root)) {
-        return;
-    }
-
-    shed__runtime__gc_push_root_gc_object((struct ShedGcObjectHeader*) gc_root);
-}
-
 // == Allocation ==
 
 struct ShedGcObjectHeader* first = NULL;
@@ -102,8 +63,8 @@ void* shed__runtime__gc_alloc(size_t size, uint32_t runtime_type_tag) {
 // == Collection ==
 
 void mark_reachable() {
-    for (size_t i = 0; i < gc_root_stack_index; i++) {
-        mark(gc_root_stack[i]);
+    for (size_t i = 0; i < shed__runtime__gc_root_stack_index; i++) {
+        mark(shed__runtime__gc_root_stack[i]);
     }
 }
 
-- 
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