feat(mem-alloc): modify obj_to_hmu for aligned detection

Convert obj_to_hmu to function that detects aligned allocations
via magic value and calculates correct HMU offset.

Author: lum1n0us

core/shared/mem-alloc/ems/ems_alloc.c

@@ -552,6 +552,23 @@ alloc_hmu_ex(gc_heap_t *heap, gc_size_t size)
     return alloc_hmu(heap, size);
 }
 
+/* Convert object pointer to HMU pointer - handles aligned allocations */
+MEM_ALLOC_API_INTER hmu_t *
+obj_to_hmu(gc_object_t obj)
+{
+    uint32_t *magic_ptr = (uint32_t *)((char *)obj - 4);
+
+    /* Check for aligned allocation magic signature */
+    if ((*magic_ptr & ALIGNED_ALLOC_MAGIC_MASK) == ALIGNED_ALLOC_MAGIC_VALUE) {
+        /* This is an aligned allocation, read offset */
+        uint32_t *offset_ptr = (uint32_t *)((char *)obj - 8);
+        return (hmu_t *)((char *)obj - *offset_ptr);
+    }
+
+    /* Normal allocation: standard offset */
+    return (hmu_t *)((gc_uint8 *)(obj) - OBJ_PREFIX_SIZE) - 1;
+}
+
 #if BH_ENABLE_GC_VERIFY == 0
 gc_object_t
 gc_alloc_vo(void *vheap, gc_size_t size)

core/shared/mem-alloc/ems/ems_gc_internal.h

@@ -127,7 +127,10 @@ hmu_verify(void *vheap, hmu_t *hmu);
 #define HMU_SIZE (sizeof(hmu_t))
 
 #define hmu_to_obj(hmu) (gc_object_t)(SKIP_OBJ_PREFIX((hmu_t *)(hmu) + 1))
-#define obj_to_hmu(obj) ((hmu_t *)((gc_uint8 *)(obj)-OBJ_PREFIX_SIZE) - 1)
+
+/* obj_to_hmu function - handles both normal and aligned allocations */
+MEM_ALLOC_API_INTER hmu_t *
+obj_to_hmu(gc_object_t obj);
 
 #define HMU_UT_SIZE 2
 #define HMU_UT_OFFSET 30