FFI: Shrink container of packed bitfield.v2.0master

Reported by Huang Haiyang. #1451

1 files changed, 2 insertions, 0 deletions

diff --git a/src/lj_cparse.c b/src/lj_cparse.c
index 45b05b36..f5c93d2e 100644
--- a/src/lj_cparse.c
+++ b/src/lj_cparse.c
@@ -1307,6 +1307,8 @@ static void cp_struct_layout(CPState *cp, CTypeID sid, CTInfo sattr)
           ct->info = CTINFO(CT_FIELD, ctype_cid(ct->info));
           ct->size = (bofs >> 3);  /* Store field offset. */
         } else {
+          if (csz > amask+1 && bsz <= amask+1)
+            csz = amask+1;  /* Shrink container of packed bitfield. */
           ct->info = CTINFO(CT_BITFIELD,
             (info & (CTF_QUAL|CTF_UNSIGNED|CTF_BOOL)) +
             (csz << (CTSHIFT_BITCSZ-3)) + (bsz << CTSHIFT_BITBSZ));