ffi: bugfix: gc-correct handling of memb array.

* ffi.c (make_ffi_type_struct): Use calloc for allocating
memb, so all the Lisp objects in it are initially nil. Then
install it into the structure upfront. Afterward, as we
iterate over the slots and types and install them into the
array, we lose references to them. But now since the array is
now wired into the FFI struct type structure, these objects
are now visible to GC.

1 files changed, 2 insertions, 2 deletions

diff --git a/ffi.c b/ffi.c
index 6e71e743..79f71538 100644
--- a/ffi.c
+++ b/ffi.c
@@ -1514,7 +1514,7 @@ static val make_ffi_type_struct(val syntax, val lisp_type,
   ffi_type **elements = coerce(ffi_type **,
                                chk_malloc(sizeof *elements * (nmemb + 1)));
   struct smemb *memb = coerce(struct smemb *,
-                              chk_malloc(sizeof *memb * nmemb));
+                              chk_calloc(nmemb, sizeof *memb));
   val obj = cobj(coerce(mem_t *, tft), ffi_type_s, &ffi_type_struct_ops);
   ucnum offs = 0;
   ucnum most_align = 0;
@@ -1533,6 +1533,7 @@ static val make_ffi_type_struct(val syntax, val lisp_type,
   tft->release = ffi_struct_release;
   tft->alloc = ffi_fixed_alloc;
   tft->free = free;
+  tft->memb = memb;
 
   for (i = 0; i < nmemb; i++) {
     val type = pop(&types);
@@ -1567,7 +1568,6 @@ static val make_ffi_type_struct(val syntax, val lisp_type,
 
   tft->size = (offs + most_align - 1) & ~(most_align - 1);
   tft->align = most_align;
-  tft->memb = memb;
 
   return obj;
 }