From 4057620bf5bcbb1ca96a6c0ffd83fa9e8a23efc8 Mon Sep 17 00:00:00 2001
From: Mike Pall <mike>
Date: Thu, 26 May 2011 18:02:42 +0200
Subject: [PATCH] Treat extra exit from stack check like a parent exit.

---
 src/lj_trace.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/src/lj_trace.c b/src/lj_trace.c
index 7141de46..d83d36e6 100644
--- a/src/lj_trace.c
+++ b/src/lj_trace.c
@@ -714,8 +714,14 @@ static TraceNo trace_exit_find(jit_State *J, MCode *pc)
   TraceNo traceno;
   for (traceno = 1; traceno < J->sizetrace; traceno++) {
     GCtrace *T = traceref(J, traceno);
-    if (T && pc >= T->mcode && pc < (MCode *)((char *)T->mcode + T->szmcode))
+    if (T && pc >= T->mcode && pc < (MCode *)((char *)T->mcode + T->szmcode)) {
+      if (J->exitno == T->nsnap) {  /* Treat stack check like a parent exit. */
+	lua_assert(T->root != 0);
+	traceno = T->ir[REF_BASE].op1;
+	J->exitno = T->ir[REF_BASE].op2;
+      }
       return traceno;
+    }
   }
   lua_assert(0);
   return 0;
@@ -735,6 +741,8 @@ int LJ_FASTCALL lj_trace_exit(jit_State *J, void *exptr)
 #ifdef EXITSTATE_PCREG
   J->parent = trace_exit_find(J, (MCode *)(intptr_t)ex->gpr[EXITSTATE_PCREG]);
 #endif
+  lua_assert(traceref(J, J->parent) != NULL &&
+	     J->exitno < traceref(J, J->parent)->nsnap);
   exd.J = J;
   exd.exptr = exptr;
   errcode = lj_vm_cpcall(L, NULL, &exd, trace_exit_cp);