1 files changed, 31 insertions, 14 deletions

diff --git a/src/lj_opt_loop.c b/src/lj_opt_loop.c
index 466f88de..ee3ee049 100644
--- a/src/lj_opt_loop.c
+++ b/src/lj_opt_loop.c
@@ -11,7 +11,7 @@
 #if LJ_HASJIT
 
 #include "lj_err.h"
-#include "lj_str.h"
+#include "lj_buf.h"
 #include "lj_ir.h"
 #include "lj_jit.h"
 #include "lj_iropt.h"
@@ -225,6 +225,7 @@ static void loop_subst_snap(jit_State *J, SnapShot *osnap,
   /* Setup new snapshot. */
   snap->mapofs = (uint32_t)nmapofs;
   snap->ref = (IRRef1)J->cur.nins;
+  snap->mcofs = 0;
   snap->nslots = nslots;
   snap->topslot = osnap->topslot;
   snap->count = 0;
@@ -254,9 +255,16 @@ static void loop_subst_snap(jit_State *J, SnapShot *osnap,
   J->cur.nsnapmap = (uint32_t)(nmap - J->cur.snapmap);
 }
 
+typedef struct LoopState {
+  jit_State *J;
+  IRRef1 *subst;
+  MSize sizesubst;
+} LoopState;
+
 /* Unroll loop. */
-static void loop_unroll(jit_State *J)
+static void loop_unroll(LoopState *lps)
 {
+  jit_State *J = lps->J;
   IRRef1 phi[LJ_MAX_PHI];
   uint32_t nphi = 0;
   IRRef1 *subst;
@@ -265,13 +273,13 @@ static void loop_unroll(jit_State *J)
   SnapEntry *loopmap, *psentinel;
   IRRef ins, invar;
 
-  /* Use temp buffer for substitution table.
+  /* Allocate substitution table.
   ** Only non-constant refs in [REF_BIAS,invar) are valid indexes.
-  ** Caveat: don't call into the VM or run the GC or the buffer may be gone.
   */
   invar = J->cur.nins;
-  subst = (IRRef1 *)lj_str_needbuf(J->L, &G(J->L)->tmpbuf,
-                                   (invar-REF_BIAS)*sizeof(IRRef1)) - REF_BIAS;
+  lps->sizesubst = invar - REF_BIAS;
+  lps->subst = lj_mem_newvec(J->L, lps->sizesubst, IRRef1);
+  subst = lps->subst - REF_BIAS;
   subst[REF_BASE] = REF_BASE;
 
   /* LOOP separates the pre-roll from the loop body. */
@@ -292,7 +300,8 @@ static void loop_unroll(jit_State *J)
   loopmap = &J->cur.snapmap[loopsnap->mapofs];
   /* The PC of snapshot #0 and the loop snapshot must match. */
   psentinel = &loopmap[loopsnap->nent];
-  lua_assert(*psentinel == J->cur.snapmap[J->cur.snap[0].nent]);
+  lj_assertJ(*psentinel == J->cur.snapmap[J->cur.snap[0].nent],
+             "mismatched PC for loop snapshot");
   *psentinel = SNAP(255, 0, 0);  /* Replace PC with temporary sentinel. */
 
   /* Start substitution with snapshot #1 (#0 is empty for root traces). */
@@ -345,10 +354,12 @@ static void loop_unroll(jit_State *J)
             irr = IR(ref);
             goto phiconv;
           }
-        } else if (ref != REF_DROP && irr->o == IR_CONV &&
-                   ref > invar && irr->op1 < invar) {
-          /* May need an extra PHI for a CONV. */
-          ref = irr->op1;
+        } else if (ref != REF_DROP && ref > invar &&
+                   ((irr->o == IR_CONV && irr->op1 < invar) ||
+                    (irr->o == IR_ALEN && irr->op2 < invar &&
+                                          irr->op2 != REF_NIL))) {
+          /* May need an extra PHI for a CONV or ALEN hint. */
+          ref = irr->o == IR_CONV ? irr->op1 : irr->op2;
           irr = IR(ref);
         phiconv:
           if (ref < invar && !irref_isk(ref) && !irt_isphi(irr->t)) {
@@ -363,7 +374,7 @@ static void loop_unroll(jit_State *J)
   }
   if (!irt_isguard(J->guardemit))  /* Drop redundant snapshot. */
     J->cur.nsnapmap = (uint32_t)J->cur.snap[--J->cur.nsnap].mapofs;
-  lua_assert(J->cur.nsnapmap <= J->sizesnapmap);
+  lj_assertJ(J->cur.nsnapmap <= J->sizesnapmap, "bad snapshot map index");
   *psentinel = J->cur.snapmap[J->cur.snap[0].nent];  /* Restore PC. */
 
   loop_emit_phi(J, subst, phi, nphi, onsnap);
@@ -396,7 +407,7 @@ static void loop_undo(jit_State *J, IRRef ins, SnapNo nsnap, MSize nsnapmap)
 static TValue *cploop_opt(lua_State *L, lua_CFunction dummy, void *ud)
 {
   UNUSED(L); UNUSED(dummy);
-  loop_unroll((jit_State *)ud);
+  loop_unroll((LoopState *)ud);
   return NULL;
 }
 
@@ -406,7 +417,13 @@ int lj_opt_loop(jit_State *J)
   IRRef nins = J->cur.nins;
   SnapNo nsnap = J->cur.nsnap;
   MSize nsnapmap = J->cur.nsnapmap;
-  int errcode = lj_vm_cpcall(J->L, NULL, J, cploop_opt);
+  LoopState lps;
+  int errcode;
+  lps.J = J;
+  lps.subst = NULL;
+  lps.sizesubst = 0;
+  errcode = lj_vm_cpcall(J->L, NULL, &lps, cploop_opt);
+  lj_mem_freevec(J2G(J), lps.subst, lps.sizesubst, IRRef1);
   if (LJ_UNLIKELY(errcode)) {
     lua_State *L = J->L;
     if (errcode == LUA_ERRRUN && tvisnumber(L->top-1)) {  /* Trace error? */