rt: take into account alignment for debug_opaque. Closes #2667

1 files changed, 6 insertions, 3 deletions

diff --git a/src/rt/rust_builtin.cpp b/src/rt/rust_builtin.cpp
index 22ebc52edf0..a8e1e7a0be4 100644
--- a/src/rt/rust_builtin.cpp
+++ b/src/rt/rust_builtin.cpp
@@ -241,10 +241,13 @@ debug_opaque(type_desc *t, uint8_t *front) {
     rust_task *task = rust_get_current_task();
     LOG(task, stdlib, "debug_opaque");
     debug_tydesc_helper(t);
-    // FIXME (#2667) may want to actually account for alignment.
-    // `front` may not indeed be the front byte of the passed-in
-    // argument.
     for (uintptr_t i = 0; i < t->size; ++front, ++i) {
+
+        // Account for alignment. `front` may not indeed be the
+        // front byte of the passed-in argument
+        if (((uintptr_t)front % t->align) != 0)
+            front = (uint8_t *)align_to((uintptr_t)front, (size_t)t->align);
+
         LOG(task, stdlib, "  byte %" PRIdPTR ": 0x%" PRIx8, i, *front);
     }
 }