From 76b28c1dc02a669f0d0c1b513c7f9283047d50be Mon Sep 17 00:00:00 2001
From: Alexander Rosenberg <zanderpkg@pm.me>
Date: Wed, 28 Jan 2026 14:54:15 -0800
Subject: [PATCH] Fix some memory leaks

---
 Makefile        |  2 +-
 src/gc.c        | 23 +++++++++++++++++++++++
 src/gc.h        |  4 ++++
 src/hashtable.c |  1 +
 src/lisp.c      |  5 ++++-
 src/list.c      |  1 +
 src/stack.c     | 16 ++++++++++++++++
 src/stack.h     |  1 +
 8 files changed, 51 insertions(+), 2 deletions(-)

diff --git a/Makefile b/Makefile
index 5ee2e03..383301a 100644
--- a/Makefile
+++ b/Makefile
@@ -1,5 +1,5 @@
 DEBUG=1
-LLVM_SAN=0
+LLVM_SAN=1
 
 ifeq ($(DEBUG),1)
 DEBUG_CFLAGS=-g
diff --git a/src/gc.c b/src/gc.c
index 865c7bf..045ef59 100644
--- a/src/gc.c
+++ b/src/gc.c
@@ -307,3 +307,26 @@ void lisp_gc_now(struct timespec *restrict time_took) {
     ++total_gc_count;
     lisp_doing_gc = false;
 }
+
+void lisp_gc_teardown(void) {
+    assert(the_stack.depth == 0);
+    while (white_objects) {
+        free_object(white_objects->obj);
+    }
+    while (grey_objects) {
+        free_object(grey_objects->obj);
+    }
+    while (black_objects) {
+        free_object(black_objects->obj);
+    }
+    while (static_objects) {
+        struct GCObjectList *next = static_objects->next;
+        free(static_objects);
+        static_objects = next;
+    }
+    while (free_objects_list) {
+        struct GCObjectList *next = free_objects_list->next;
+        free(free_objects_list);
+        free_objects_list = next;
+    }
+}
diff --git a/src/gc.h b/src/gc.h
index fe81348..b2e0a0f 100644
--- a/src/gc.h
+++ b/src/gc.h
@@ -33,4 +33,8 @@ void gc_move_to_set(void *val, ObjectGCSet new_set);
 
 void lisp_gc_now(struct timespec *restrict time_took);
 
+// Unregister all static objects and prepare for shutdown
+// The stack MUST be empty when this is called
+void lisp_gc_teardown(void);
+
 #endif
diff --git a/src/hashtable.c b/src/hashtable.c
index 8f5b010..02090e0 100644
--- a/src/hashtable.c
+++ b/src/hashtable.c
@@ -92,6 +92,7 @@ static void rehash(LispHashTable *ht, size_t new_size) {
             nb->value = cob->value;
         }
     }
+    lisp_free(old_data);
 }
 
 static void maybe_rehash(LispHashTable *ht) {
diff --git a/src/lisp.c b/src/lisp.c
index d1d1424..affb0a7 100644
--- a/src/lisp.c
+++ b/src/lisp.c
@@ -52,7 +52,10 @@ void lisp_init(void) {
     lisp_init_stack();
 }
 
-void lisp_shutdown(void) {}
+void lisp_shutdown(void) {
+    lisp_gc_teardown();
+    lisp_teardown_stack();
+}
 
 DEFUN(eval, "eval", (LispVal * form), "(form)", "") {
     if (!OBJECTP(form)) {
diff --git a/src/list.c b/src/list.c
index efc4b09..cc45a59 100644
--- a/src/list.c
+++ b/src/list.c
@@ -31,6 +31,7 @@ DEFUN(cons, "cons", (LispVal * car, LispVal *cdr), "(car cdr)",
 
 DEFUN(length, "length", (LispVal * list), "(list)", "") {
     // TODO type check
+    // TODO list may be circular
     return MAKE_FIXNUM(list_length(list));
 }
 
diff --git a/src/stack.c b/src/stack.c
index 2a31b3f..eacee16 100644
--- a/src/stack.c
+++ b/src/stack.c
@@ -26,6 +26,21 @@ void lisp_init_stack(void) {
     the_stack.nogc_retval = Qnil;
 }
 
+static void teardown_stack_frame(struct StackFrame *restrict frame) {
+    for (size_t i = 0; i < frame->local_refs.num_blocks; ++i) {
+        lisp_free(frame->local_refs.blocks[i]);
+    }
+    lisp_free(frame->local_refs.blocks);
+}
+
+void lisp_teardown_stack(void) {
+    assert(the_stack.depth == 0);
+    for (size_t i = 0; i < the_stack.max_depth; ++i) {
+        teardown_stack_frame(&the_stack.frames[i]);
+    }
+    lisp_free(the_stack.frames);
+}
+
 void push_stack_frame(LispVal *name, LispVal *fobj, LispVal *args) {
     assert(the_stack.depth < the_stack.max_depth);
     struct StackFrame *frame = &the_stack.frames[the_stack.depth++];
@@ -164,6 +179,7 @@ void add_local_reference(LispVal *obj) {
     while ((cur = next_local_reference(&i))) {
         add_local_refs_for_object_sub_vals(seen_objs, cur);
     }
+    release_hash_table_no_gc(seen_objs);
 }
 
 void compact_stack_frame(struct StackFrame *restrict frame) {
diff --git a/src/stack.h b/src/stack.h
index c6945d2..85c53f7 100644
--- a/src/stack.h
+++ b/src/stack.h
@@ -41,6 +41,7 @@ static ALWAYS_INLINE struct StackFrame *LISP_STACK_TOP(void) {
 }
 
 void lisp_init_stack(void);
+void lisp_teardown_stack(void);
 void push_stack_frame(LispVal *name, LispVal *fobj, LispVal *args);
 void pop_stack_frame(void);
 void add_local_reference_no_recurse(LispVal *obj);