Broadening the use of branch hints

More uses of macros 'likely'/'unlikely' (renamed to
'l_likely'/'l_unlikely'), both in range (extended to the
libraries) and in scope (extended to hooks, stack growth).

lvm.c

@@ -235,11 +235,11 @@ static int forprep (lua_State *L, StkId ra) {
   }
   else {  /* try making all values floats */
     lua_Number init; lua_Number limit; lua_Number step;
-    if (unlikely(!tonumber(plimit, &limit)))
+    if (l_unlikely(!tonumber(plimit, &limit)))
       luaG_forerror(L, plimit, "limit");
-    if (unlikely(!tonumber(pstep, &step)))
+    if (l_unlikely(!tonumber(pstep, &step)))
       luaG_forerror(L, pstep, "step");
-    if (unlikely(!tonumber(pinit, &init)))
+    if (l_unlikely(!tonumber(pinit, &init)))
       luaG_forerror(L, pinit, "initial value");
     if (step == 0)
       luaG_runerror(L, "'for' step is zero");
@@ -292,7 +292,7 @@ void luaV_finishget (lua_State *L, const TValue *t, TValue *key, StkId val,
     if (slot == NULL) {  /* 't' is not a table? */
       lua_assert(!ttistable(t));
       tm = luaT_gettmbyobj(L, t, TM_INDEX);
-      if (unlikely(notm(tm)))
+      if (l_unlikely(notm(tm)))
         luaG_typeerror(L, t, "index");  /* no metamethod */
       /* else will try the metamethod */
     }
@@ -346,7 +346,7 @@ void luaV_finishset (lua_State *L, const TValue *t, TValue *key,
     }
     else {  /* not a table; check metamethod */
       tm = luaT_gettmbyobj(L, t, TM_NEWINDEX);
-      if (unlikely(notm(tm)))
+      if (l_unlikely(notm(tm)))
         luaG_typeerror(L, t, "index");
     }
     /* try the metamethod */
@@ -651,7 +651,7 @@ void luaV_concat (lua_State *L, int total) {
       /* collect total length and number of strings */
       for (n = 1; n < total && tostring(L, s2v(top - n - 1)); n++) {
         size_t l = vslen(s2v(top - n - 1));
-        if (unlikely(l >= (MAX_SIZE/sizeof(char)) - tl))
+        if (l_unlikely(l >= (MAX_SIZE/sizeof(char)) - tl))
           luaG_runerror(L, "string length overflow");
         tl += l;
       }
@@ -695,7 +695,7 @@ void luaV_objlen (lua_State *L, StkId ra, const TValue *rb) {
     }
     default: {  /* try metamethod */
       tm = luaT_gettmbyobj(L, rb, TM_LEN);
-      if (unlikely(notm(tm)))  /* no metamethod? */
+      if (l_unlikely(notm(tm)))  /* no metamethod? */
         luaG_typeerror(L, rb, "get length of");
       break;
     }
@@ -711,7 +711,7 @@ void luaV_objlen (lua_State *L, StkId ra, const TValue *rb) {
 ** otherwise 'floor(q) == trunc(q) - 1'.
 */
 lua_Integer luaV_idiv (lua_State *L, lua_Integer m, lua_Integer n) {
-  if (unlikely(l_castS2U(n) + 1u <= 1u)) {  /* special cases: -1 or 0 */
+  if (l_unlikely(l_castS2U(n) + 1u <= 1u)) {  /* special cases: -1 or 0 */
     if (n == 0)
       luaG_runerror(L, "attempt to divide by zero");
     return intop(-, 0, m);   /* n==-1; avoid overflow with 0x80000...//-1 */
@@ -731,7 +731,7 @@ lua_Integer luaV_idiv (lua_State *L, lua_Integer m, lua_Integer n) {
 ** about luaV_idiv.)
 */
 lua_Integer luaV_mod (lua_State *L, lua_Integer m, lua_Integer n) {
-  if (unlikely(l_castS2U(n) + 1u <= 1u)) {  /* special cases: -1 or 0 */
+  if (l_unlikely(l_castS2U(n) + 1u <= 1u)) {  /* special cases: -1 or 0 */
     if (n == 0)
       luaG_runerror(L, "attempt to perform 'n%%0'");
     return 0;   /* m % -1 == 0; avoid overflow with 0x80000...%-1 */
@@ -1049,7 +1049,8 @@ void luaV_finishOp (lua_State *L) {
 #define updatebase(ci)	(base = ci->func + 1)
 
 
-#define updatestack(ci) { if (trap) { updatebase(ci); ra = RA(i); } }
+#define updatestack(ci)  \
+	{ if (l_unlikely(trap)) { updatebase(ci); ra = RA(i); } }
 
 
 /*
@@ -1107,7 +1108,7 @@ void luaV_finishOp (lua_State *L) {
 
 /* fetch an instruction and prepare its execution */
 #define vmfetch()	{ \
-  if (trap) {  /* stack reallocation or hooks? */ \
+  if (l_unlikely(trap)) {  /* stack reallocation or hooks? */ \
     trap = luaG_traceexec(L, pc);  /* handle hooks */ \
     updatebase(ci);  /* correct stack */ \
   } \
@@ -1135,7 +1136,7 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
   cl = clLvalue(s2v(ci->func));
   k = cl->p->k;
   pc = ci->u.l.savedpc;
-  if (trap) {
+  if (l_unlikely(trap)) {
     if (pc == cl->p->code) {  /* first instruction (not resuming)? */
       if (cl->p->is_vararg)
         trap = 0;  /* hooks will start after VARARGPREP instruction */
@@ -1678,23 +1679,23 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
         goto ret;
       }
       vmcase(OP_RETURN0) {
-        if (L->hookmask) {
+        if (l_unlikely(L->hookmask)) {
           L->top = ra;
           savepc(ci);
           luaD_poscall(L, ci, 0);  /* no hurry... */
           trap = 1;
         }
         else {  /* do the 'poscall' here */
-          int nres = ci->nresults;
+          int nres;
           L->ci = ci->previous;  /* back to caller */
           L->top = base - 1;
-          while (nres-- > 0)
+          for (nres = ci->nresults; l_unlikely(nres > 0); nres--)
             setnilvalue(s2v(L->top++));  /* all results are nil */
         }
         goto ret;
       }
       vmcase(OP_RETURN1) {
-        if (L->hookmask) {
+        if (l_unlikely(L->hookmask)) {
           L->top = ra + 1;
           savepc(ci);
           luaD_poscall(L, ci, 1);  /* no hurry... */
@@ -1708,8 +1709,8 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
           else {
             setobjs2s(L, base - 1, ra);  /* at least this result */
             L->top = base;
-            while (--nres > 0)  /* complete missing results */
-              setnilvalue(s2v(L->top++));
+            for (; l_unlikely(nres > 1); nres--)
+              setnilvalue(s2v(L->top++));  /* complete missing results */
           }
         }
        ret:  /* return from a Lua function */
@@ -1812,7 +1813,7 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
       }
       vmcase(OP_VARARGPREP) {
         ProtectNT(luaT_adjustvarargs(L, GETARG_A(i), ci, cl->p));
-        if (trap) {
+        if (l_unlikely(trap)) {  /* previous "Protect" updated trap */
           luaD_hookcall(L, ci);
           L->oldpc = 1;  /* next opcode will be seen as a "new" line */
         }