Better document missing debugging version for aligned allocation routines

* dbg_mlc.c (GC_debug_free): Add TODO item to suppress a GC warning.
* include/gc/leak_detector.h (aligned_alloc): Add comment that the
debugging version is missing.
* mallocx.c (GC_memalign): Add TODO item about the missing debugging
version.

1 files changed, 9 insertions, 1 deletions

diff --git a/mallocx.c b/mallocx.c
index 47cca9ee..cd0fc527 100644
--- a/mallocx.c
+++ b/mallocx.c
@@ -491,7 +491,15 @@ GC_API GC_ATTR_MALLOC void * GC_CALL GC_malloc_many(size_t lb)
     return result;
 }
 
-/* Debug version is tricky and currently missing.       */
+/* TODO: The debugging version of GC_memalign and friends is tricky     */
+/* and currently missing.  There are 2 major difficulties:              */
+/* - GC_base() should always point to the beginning of the allocated    */
+/* block (thus, for small objects allocation we should probably         */
+/* iterate over the list of free objects to find the one with the       */
+/* suitable alignment);                                                 */
+/* - store_debug_info() should return the pointer of the object with    */
+/* the requested alignment (unlike the object header).                  */
+
 GC_API GC_ATTR_MALLOC void * GC_CALL GC_memalign(size_t align, size_t lb)
 {
     size_t offset;