From 3c9fafb11afb507c476e037f6bf827a54113f524 Mon Sep 17 00:00:00 2001
From: Andre Wagner <andre.nho@gmail.com>
Date: Tue, 12 May 2026 20:09:40 -0500
Subject: [PATCH] .

---
 Makefile     |  2 +-
 lib/heap.c   | 51 +++++++++++++++++++++++++++++++++------------------
 test/tests.c | 33 ++++++++++++++++++++++++++++++++-
 3 files changed, 66 insertions(+), 20 deletions(-)

diff --git a/Makefile b/Makefile
index c567b36..0a99dcd 100644
--- a/Makefile
+++ b/Makefile
@@ -30,7 +30,7 @@ endif
 
 # debug and release flags
 
-DEBUG_CFLAGS=-Og -ggdb3 ${WARNINGS} -fno-omit-frame-pointer -fsanitize=address -fsanitize=undefined \
+DEBUG_CFLAGS=-O0 -ggdb3 ${WARNINGS} -fno-omit-frame-pointer -fsanitize=address -fsanitize=undefined \
   -fno-sanitize-recover=all -fstack-protector-strong -fstack-clash-protection -fno-common ${ADD_DBG_FLAGS} \
   -DCHECK_TYCHE_BUGS=1
 DEBUG_LDFLAGS=-fsanitize=address -fsanitize=undefined
diff --git a/lib/heap.c b/lib/heap.c
index 5b7f137..ffba83d 100644
--- a/lib/heap.c
+++ b/lib/heap.c
@@ -2,6 +2,7 @@
 
 #include <stdlib.h>
 #include <string.h>
+#include <stdio.h>
 
 #include "khash.h"
 
@@ -18,7 +19,7 @@ typedef struct {
         // TODO - array and table
     } value;
 } HeapValue;
-KHASH_MAP_INIT_INT(HEAP, HeapValue)
+KHASH_MAP_INIT_INT64(HEAP, HeapValue)
 
 typedef struct {
     khash_t(HEAP) *items;
@@ -29,20 +30,27 @@ static void heap_init(Heap* h)
     h->items = kh_init(HEAP);
 }
 
+static void heap_free_item(HeapValue value)
+{
+    switch (value.type) {
+        case TH_STRING:
+            free(value.value.str);
+            break;
+        case TH_ARRAY:
+            abort();  // not implemented yet
+            break;
+        case TH_TABLE:
+            abort();  // not implemented yet
+            break;
+    }
+}
+
 static void heap_finalize(Heap* h)
 {
     for (khiter_t k = kh_begin(h->items); k != kh_end(h->items); ++k) {
-        HeapValue value = kh_value(h->items, k);
-        switch (value.type) {
-            case TH_STRING:
-                free(value.value.str);
-                break;
-            case TH_ARRAY:
-                abort();  // not implemented yet
-                break;
-            case TH_TABLE:
-                abort();  // not implemented yet
-                break;
+        if (kh_exist(h->items, k)) {
+            HeapValue value = kh_value(h->items, k);
+            heap_free_item(value);
         }
     }
     kh_destroy(HEAP, h->items);
@@ -88,7 +96,8 @@ static size_t heap_size(Heap* h)
 // GC
 //
 
-KHASH_MAP_INIT_INT(MARK, bool)
+KHASH_MAP_INIT_INT64(MARK, bool)
+
 static void heap_gc(Heap* h, VALUE const* roots, size_t n_roots)
 {
     //
@@ -100,7 +109,8 @@ static void heap_gc(Heap* h, VALUE const* roots, size_t n_roots)
     for (size_t i = 0; i < n_roots; ++i) {
         if (value_type(roots[i]) == TT_STRING) {
             int ret;
-            khiter_t k = kh_put(MARK, marked, value_idx(roots[i]), &ret);
+            uint32_t key = value_idx(roots[i]);
+            khiter_t k = kh_put(MARK, marked, key, &ret);
             kh_value(marked, k) = true;
         }
     }
@@ -109,10 +119,15 @@ static void heap_gc(Heap* h, VALUE const* roots, size_t n_roots)
     // sweep
     //
 
-    for (khiter_t k = kh_begin(marked); k != kh_end(marked); ++k) {
-        HEAP_KEY key = kh_value(marked, k);
-        khiter_t item = kh_get(HEAP, h->items, key);
-        kh_del(HEAP, h->items, item);
+    for (khiter_t k = kh_begin(h->items); k != kh_end(h->items); ++k) {
+        if (kh_exist(h->items, k)) {
+            HEAP_KEY key = kh_key(h->items, k);
+            if (kh_get(MARK, marked, key) == kh_end(marked)) {
+                khiter_t kk = kh_get(HEAP, h->items, key);
+                heap_free_item(kh_value(h->items, kk));
+                kh_del(HEAP, h->items, kk);
+            }
+        }
     }
 
     kh_destroy(MARK, marked);
diff --git a/test/tests.c b/test/tests.c
index 2c11110..b12e7a0 100644
--- a/test/tests.c
+++ b/test/tests.c
@@ -93,7 +93,7 @@ int main()
     }
 
     {
-        printf("### Heap\n");
+        printf("### Heap - strings\n");
 
         Heap h;
         heap_init(&h);
@@ -108,4 +108,35 @@ int main()
 
         heap_finalize(&h);
     }
+
+    {
+        printf("### Heap - string GC\n");
+
+        Stack s;
+        stack_init(&s);
+
+        Heap h;
+        heap_init(&h);
+
+        stack_push(&s, create_value_idx(TT_STRING, heap_add_string(&h, "item1")));
+        stack_push(&s, create_value_idx(TT_STRING, heap_add_string(&h, "item2")));
+        stack_push(&s, create_value_idx(TT_STRING, heap_add_string(&h, "item3")));
+
+        assert(heap_size(&h) == 3);
+        heap_gc(&h, s.stack, s.stack_n);
+        assert(heap_size(&h) == 3);
+
+        stack_pop(&s, NULL);
+
+        assert(heap_size(&h) == 3);
+        heap_gc(&h, s.stack, s.stack_n);
+        assert(heap_size(&h) == 2);
+
+        stack_pop(&s, NULL);
+        heap_gc(&h, s.stack, s.stack_n);
+        assert(heap_size(&h) == 1);
+
+        heap_finalize(&h);
+        stack_finalize(&s);
+    }
 }
\ No newline at end of file