Fix compiled error handling for buffer methods.

Contributed by XmiliaH.

src/lj_ffrecord.c

@@ -1222,6 +1222,12 @@ static void LJ_FASTCALL recff_buffer_method_put(jit_State *J, RecordFFData *rd)
   TRef tr;
   ptrdiff_t arg;
   if (!J->base[1]) return;
+  for (arg = 1; (tr = J->base[arg]); arg++) {
+    if (tref_isudata(tr)) {
+      TRef ud2 = recff_sbufx_check(J, rd, arg);
+      emitir(IRTG(IR_NE, IRT_PGC), ud, ud2);
+    }
+  }
   for (arg = 1; (tr = J->base[arg]); arg++) {
     if (tref_isstr(tr)) {
       trbuf = emitir(IRTG(IR_BUFPUT, IRT_PGC), trbuf, tr);
@@ -1230,11 +1236,9 @@ static void LJ_FASTCALL recff_buffer_method_put(jit_State *J, RecordFFData *rd)
 		     emitir(IRT(IR_TOSTR, IRT_STR), tr,
 			    tref_isnum(tr) ? IRTOSTR_NUM : IRTOSTR_INT));
     } else if (tref_isudata(tr)) {
-      TRef ud2 = recff_sbufx_check(J, rd, arg);
-      TRef trr = recff_sbufx_get_ptr(J, ud2, IRFL_SBUF_R);
-      TRef trw = recff_sbufx_get_ptr(J, ud2, IRFL_SBUF_W);
+      TRef trr = recff_sbufx_get_ptr(J, tr, IRFL_SBUF_R);
+      TRef trw = recff_sbufx_get_ptr(J, tr, IRFL_SBUF_W);
       TRef len = recff_sbufx_len(J, trr, trw);
-      emitir(IRTG(IR_NE, IRT_PGC), ud, ud2);
       trbuf = lj_ir_call(J, IRCALL_lj_buf_putmem, trbuf, trr, len);
     } else {
       recff_nyiu(J, rd);
@@ -1258,15 +1262,19 @@ static void LJ_FASTCALL recff_buffer_method_get(jit_State *J, RecordFFData *rd)
   TRef tr;
   ptrdiff_t arg;
   if (!J->base[1]) { J->base[1] = TREF_NIL; J->base[2] = 0; }
+  for (arg = 0; (tr = J->base[arg+1]); arg++) {
+    if (!tref_isnil(tr)) {
+      J->base[arg+1] = recff_sbufx_checkint(J, rd, arg+1);
+    }
+  }
   for (arg = 0; (tr = J->base[arg+1]); arg++) {
     TRef len = recff_sbufx_len(J, trr, trw);
     if (tref_isnil(tr)) {
       J->base[arg] = emitir(IRT(IR_XSNEW, IRT_STR), trr, len);
       trr = trw;
     } else {
-      TRef trn = recff_sbufx_checkint(J, rd, arg+1);
       TRef tru;
-      len = emitir(IRTI(IR_MIN), len, trn);
+      len = emitir(IRTI(IR_MIN), len, tr);
       tru = emitir(IRT(IR_ADD, IRT_PTR), trr, len);
       J->base[arg] = emitir(IRT(IR_XSNEW, IRT_STR), trr, len);
       trr = tru;  /* Doing the ADD before the SNEW generates better code. */