Use dedicated type for snapshot map entry.

Preparatory work for compressed snapshots.

8 files changed, 36 insertions, 33 deletions

diff --git a/src/lib_jit.c b/src/lib_jit.c
index d849ded4..aa421613 100644
--- a/src/lib_jit.c
+++ b/src/lib_jit.c
@@ -331,7 +331,7 @@ LJLIB_CF(jit_util_tracesnap)
   SnapNo sn = (SnapNo)lj_lib_checkint(L, 2);
   if (T && sn < T->nsnap) {
     SnapShot *snap = &T->snap[sn];
-    IRRef2 *map = &T->snapmap[snap->mapofs];
+    SnapEntry *map = &T->snapmap[snap->mapofs];
     BCReg s, nslots = snap->nslots;
     GCtab *t;
     lua_createtable(L, nslots ? (int)nslots : 1, 0);
diff --git a/src/lj_asm.c b/src/lj_asm.c
index eeb6aeb4..a8cb3dd0 100644
--- a/src/lj_asm.c
+++ b/src/lj_asm.c
@@ -925,7 +925,7 @@ static int asm_snap_canremat(ASMState *as)
 static void asm_snap_alloc(ASMState *as)
 {
   SnapShot *snap = &as->T->snap[as->snapno];
-  IRRef2 *map = &as->T->snapmap[snap->mapofs];
+  SnapEntry *map = &as->T->snapmap[snap->mapofs];
   BCReg s, nslots = snap->nslots;
   for (s = 0; s < nslots; s++) {
     IRRef ref = snap_ref(map[s]);
@@ -959,7 +959,7 @@ static void asm_snap_alloc(ASMState *as)
 static int asm_snap_checkrename(ASMState *as, IRRef ren)
 {
   SnapShot *snap = &as->T->snap[as->snapno];
-  IRRef2 *map = &as->T->snapmap[snap->mapofs];
+  SnapEntry *map = &as->T->snapmap[snap->mapofs];
   BCReg s, nslots = snap->nslots;
   for (s = 0; s < nslots; s++) {
     IRRef ref = snap_ref(map[s]);
@@ -2463,7 +2463,7 @@ static void asm_gc_sync(ASMState *as, SnapShot *snap, Reg base)
   ** only. This avoids register allocation state unification.
   */
   RegSet allow = rset_exclude(RSET_SCRATCH & RSET_GPR, base);
-  IRRef2 *map = &as->T->snapmap[snap->mapofs];
+  SnapEntry *map = &as->T->snapmap[snap->mapofs];
   BCReg s, nslots = snap->nslots;
   for (s = 0; s < nslots; s++) {
     IRRef ref = snap_ref(map[s]);
@@ -2965,8 +2965,8 @@ static void asm_tail_sync(ASMState *as)
 {
   SnapShot *snap = &as->T->snap[as->T->nsnap-1];  /* Last snapshot. */
   BCReg s, nslots = snap->nslots;
-  IRRef2 *map = &as->T->snapmap[snap->mapofs];
-  IRRef2 *flinks = map + nslots + snap->nframelinks;
+  SnapEntry *map = &as->T->snapmap[snap->mapofs];
+  SnapEntry *flinks = map + nslots + snap->nframelinks;
   BCReg newbase = 0;
   BCReg secondbase = ~(BCReg)0;
   BCReg topslot = 0;
diff --git a/src/lj_jit.h b/src/lj_jit.h
index c783922c..36e60113 100644
--- a/src/lj_jit.h
+++ b/src/lj_jit.h
@@ -119,8 +119,10 @@ typedef struct SnapShot {
 } SnapShot;
 
 #define SNAPCOUNT_DONE  255     /* Already compiled and linked a side trace. */
-#define snap_ref(sn)    ((IRRef)(IRRef1)(sn))
-#define snap_ridsp(sn)  ((sn) >> 16)
+
+/* Snapshot entry. */
+typedef uint32_t SnapEntry;
+#define snap_ref(sn)            ((sn) & 0xffff)
 
 /* Snapshot and exit numbers. */
 typedef uint32_t SnapNo;
@@ -138,7 +140,7 @@ typedef struct Trace {
   IRRef nins;           /* Next IR instruction. Biased with REF_BIAS. */
   IRRef nk;             /* Lowest IR constant. Biased with REF_BIAS. */
   SnapShot *snap;       /* Snapshot array. */
-  IRRef2 *snapmap;      /* Snapshot map. */
+  SnapEntry *snapmap;   /* Snapshot map. */
   uint16_t nsnap;       /* Number of snapshots. */
   uint16_t nsnapmap;    /* Number of snapshot map elements. */
   GCRef startpt;        /* Starting prototype. */
@@ -223,7 +225,7 @@ typedef struct jit_State {
   IRRef loopref;        /* Last loop reference or ref of final LOOP (or 0). */
 
   SnapShot *snapbuf;    /* Temp. snapshot buffer. */
-  IRRef2 *snapmapbuf;   /* Temp. snapshot map buffer. */
+  SnapEntry *snapmapbuf;  /* Temp. snapshot map buffer. */
   MSize sizesnap;       /* Size of temp. snapshot buffer. */
   MSize sizesnapmap;    /* Size of temp. snapshot map buffer. */
 
diff --git a/src/lj_opt_dce.c b/src/lj_opt_dce.c
index e304d9fc..636d5183 100644
--- a/src/lj_opt_dce.c
+++ b/src/lj_opt_dce.c
@@ -23,7 +23,7 @@ static void dce_marksnap(jit_State *J)
   SnapNo i, nsnap = J->cur.nsnap;
   for (i = 0; i < nsnap; i++) {
     SnapShot *snap = &J->cur.snap[i];
-    IRRef2 *map = &J->cur.snapmap[snap->mapofs];
+    SnapEntry *map = &J->cur.snapmap[snap->mapofs];
     BCReg s, nslots = snap->nslots;
     for (s = 0; s < nslots; s++) {
       IRRef ref = snap_ref(map[s]);
diff --git a/src/lj_opt_loop.c b/src/lj_opt_loop.c
index 1fbc8091..f2950fe9 100644
--- a/src/lj_opt_loop.c
+++ b/src/lj_opt_loop.c
@@ -170,7 +170,7 @@ static void loop_unroll(jit_State *J)
   uint32_t nphi = 0;
   IRRef1 *subst;
   SnapShot *osnap, *snap;
-  IRRef2 *loopmap;
+  SnapEntry *loopmap;
   BCReg loopslots;
   MSize nsnap, nsnapmap;
   IRRef ins, invar, osnapref;
@@ -198,9 +198,9 @@ static void loop_unroll(jit_State *J)
   }
   nsnapmap = J->cur.nsnapmap;  /* Use temp. copy to avoid undo. */
   if (LJ_UNLIKELY(nsnapmap*2 > J->sizesnapmap)) {
-    J->snapmapbuf = (IRRef2 *)lj_mem_realloc(J->L, J->snapmapbuf,
-                                             J->sizesnapmap*sizeof(IRRef2),
-                                             2*J->sizesnapmap*sizeof(IRRef2));
+    J->snapmapbuf = (SnapEntry *)lj_mem_realloc(J->L, J->snapmapbuf,
+                      J->sizesnapmap*sizeof(SnapEntry),
+                      2*J->sizesnapmap*sizeof(SnapEntry));
     J->cur.snapmap = J->snapmapbuf;
     J->sizesnapmap *= 2;
   }
@@ -223,7 +223,7 @@ static void loop_unroll(jit_State *J)
 
     /* Copy-substitute snapshot. */
     if (ins >= osnapref) {
-      IRRef2 *nmap, *omap = &J->cur.snapmap[osnap->mapofs];
+      SnapEntry *nmap, *omap = &J->cur.snapmap[osnap->mapofs];
       BCReg s, nslots;
       uint32_t nmapofs, nframelinks;
       if (irt_isguard(J->guardemit)) {  /* Guard inbetween? */
diff --git a/src/lj_record.c b/src/lj_record.c
index 5085d735..329cbdc5 100644
--- a/src/lj_record.c
+++ b/src/lj_record.c
@@ -2158,7 +2158,7 @@ static const BCIns *rec_setup_root(jit_State *J)
 static void rec_setup_side(jit_State *J, Trace *T)
 {
   SnapShot *snap = &T->snap[J->exitno];
-  IRRef2 *map = &T->snapmap[snap->mapofs];
+  SnapEntry *map = &T->snapmap[snap->mapofs];
   BCReg s, nslots = snap->nslots;
   BloomFilter seen = 0;
   for (s = 0; s < nslots; s++) {
diff --git a/src/lj_snap.c b/src/lj_snap.c
index e2a49ae3..c2aff3db 100644
--- a/src/lj_snap.c
+++ b/src/lj_snap.c
@@ -32,7 +32,7 @@
 */
 
 /* Add all modified slots to the snapshot. */
-static void snapshot_slots(jit_State *J, IRRef2 *map, BCReg nslots)
+static MSize snapshot_slots(jit_State *J, SnapEntry *map, BCReg nslots)
 {
   BCReg s;
   for (s = 0; s < nslots; s++) {
@@ -42,12 +42,13 @@ static void snapshot_slots(jit_State *J, IRRef2 *map, BCReg nslots)
       if (ir->o == IR_SLOAD && ir->op1 == s && !(ir->op2 & IRSLOAD_INHERIT))
         ref = 0;
     }
-    map[s] = (IRRef2)ref;
+    map[s] = (SnapEntry)ref;
   }
+  return nslots;
 }
 
 /* Add frame links at the end of the snapshot. */
-static MSize snapshot_framelinks(jit_State *J, IRRef2 *map)
+static MSize snapshot_framelinks(jit_State *J, SnapEntry *map)
 {
   cTValue *frame = J->L->base - 1;
   cTValue *lim = J->L->base - J->baseslot;
@@ -76,7 +77,7 @@ static void snapshot_stack(jit_State *J, SnapShot *snap, MSize nsnapmap)
 {
   BCReg nslots = J->baseslot + J->maxslot;
   MSize nsm, nframelinks;
-  IRRef2 *p;
+  SnapEntry *p;
   /* Conservative estimate. Continuation frames need 2 slots. */
   nsm = nsnapmap + nslots + (uint32_t)J->framedepth*2+1;
   if (LJ_UNLIKELY(nsm > J->sizesnapmap)) {  /* Need to grow snapshot map? */
@@ -84,13 +85,13 @@ static void snapshot_stack(jit_State *J, SnapShot *snap, MSize nsnapmap)
       nsm = 2*J->sizesnapmap;
     else if (nsm < 64)
       nsm = 64;
-    J->snapmapbuf = (IRRef2 *)lj_mem_realloc(J->L, J->snapmapbuf,
-                      J->sizesnapmap*sizeof(IRRef2), nsm*sizeof(IRRef2));
+    J->snapmapbuf = (SnapEntry *)lj_mem_realloc(J->L, J->snapmapbuf,
+                      J->sizesnapmap*sizeof(SnapEntry), nsm*sizeof(SnapEntry));
     J->cur.snapmap = J->snapmapbuf;
     J->sizesnapmap = nsm;
   }
   p = &J->cur.snapmap[nsnapmap];
-  snapshot_slots(J, p, nslots);
+  nslots = snapshot_slots(J, p, nslots);
   nframelinks = snapshot_framelinks(J, p + nslots);
   J->cur.nsnapmap = (uint16_t)(nsnapmap + nslots + nframelinks);
   snap->mapofs = (uint16_t)nsnapmap;
@@ -130,8 +131,8 @@ void lj_snap_shrink(jit_State *J)
 {
   BCReg nslots = J->baseslot + J->maxslot;
   SnapShot *snap = &J->cur.snap[J->cur.nsnap-1];
-  IRRef2 *oflinks = &J->cur.snapmap[snap->mapofs + snap->nslots];
-  IRRef2 *nflinks = &J->cur.snapmap[snap->mapofs + nslots];
+  SnapEntry *oflinks = &J->cur.snapmap[snap->mapofs + snap->nslots];
+  SnapEntry *nflinks = &J->cur.snapmap[snap->mapofs + nslots];
   uint32_t s, nframelinks = snap->nframelinks;
   lua_assert(nslots < snap->nslots);
   snap->nslots = (uint8_t)nslots;
@@ -171,7 +172,7 @@ void lj_snap_regspmap(uint16_t *rsmap, Trace *T, SnapNo snapno)
 {
   SnapShot *snap = &T->snap[snapno];
   BCReg s, nslots = snap->nslots;
-  IRRef2 *map = &T->snapmap[snap->mapofs];
+  SnapEntry *map = &T->snapmap[snap->mapofs];
   BloomFilter rfilt = snap_renamefilter(T, snapno);
   for (s = 0; s < nslots; s++) {
     IRRef ref = snap_ref(map[s]);
@@ -193,8 +194,8 @@ void lj_snap_restore(jit_State *J, void *exptr)
   Trace *T = J->trace[J->parent];
   SnapShot *snap = &T->snap[snapno];
   BCReg s, nslots = snap->nslots;
-  IRRef2 *map = &T->snapmap[snap->mapofs];
-  IRRef2 *flinks = map + nslots + snap->nframelinks;
+  SnapEntry *map = &T->snapmap[snap->mapofs];
+  SnapEntry *flinks = map + nslots + snap->nframelinks;
   TValue *o, *newbase, *ntop;
   BloomFilter rfilt = snap_renamefilter(T, snapno);
   lua_State *L = J->L;
diff --git a/src/lj_trace.c b/src/lj_trace.c
index 683b8a58..a5468655 100644
--- a/src/lj_trace.c
+++ b/src/lj_trace.c
@@ -88,7 +88,7 @@ static Trace *trace_save(jit_State *J, Trace *T)
   size_t szins = (T->nins-T->nk)*sizeof(IRIns);
   size_t sz = sztr + szins +
               T->nsnap*sizeof(SnapShot) +
-              T->nsnapmap*sizeof(IRRef2);
+              T->nsnapmap*sizeof(SnapEntry);
   Trace *T2 = lj_mem_newt(J->L, (MSize)sz, Trace);
   char *p = (char *)T2 + sztr;
   memcpy(T2, T, sizeof(Trace));
@@ -96,7 +96,7 @@ static Trace *trace_save(jit_State *J, Trace *T)
   memcpy(p, T->ir+T->nk, szins);
   p += szins;
   TRACE_COPYELEM(snap, nsnap, SnapShot)
-  TRACE_COPYELEM(snapmap, nsnapmap, IRRef2)
+  TRACE_COPYELEM(snapmap, nsnapmap, SnapEntry)
   lj_gc_barriertrace(J2G(J), T);
   return T2;
 }
@@ -118,7 +118,7 @@ static void trace_free(jit_State *J, TraceNo traceno)
     J->trace[traceno] = NULL;
     lj_mem_free(J2G(J), T,
       ((sizeof(Trace)+7)&~7) + (T->nins-T->nk)*sizeof(IRIns) +
-      T->nsnap*sizeof(SnapShot) + T->nsnapmap*sizeof(IRRef2));
+      T->nsnap*sizeof(SnapShot) + T->nsnapmap*sizeof(SnapEntry));
   }
 }
 
@@ -284,7 +284,7 @@ void lj_trace_freestate(global_State *g)
 #endif
   lj_mcode_free(J);
   lj_ir_knum_freeall(J);
-  lj_mem_freevec(g, J->snapmapbuf, J->sizesnapmap, IRRef2);
+  lj_mem_freevec(g, J->snapmapbuf, J->sizesnapmap, SnapEntry);
   lj_mem_freevec(g, J->snapbuf, J->sizesnap, SnapShot);
   lj_mem_freevec(g, J->irbuf + J->irbotlim, J->irtoplim - J->irbotlim, IRIns);
   lj_mem_freevec(g, J->trace, J->sizetrace, Trace *);