Introduce setobjs2s

6 files changed, 42 insertions, 36 deletions

diff --git a/src/lapi.js b/src/lapi.js
index 92e1612..00e608f 100644
--- a/src/lapi.js
+++ b/src/lapi.js
@@ -163,7 +163,7 @@ const lua_pop = function(L, n) {
 const reverse = function(L, from, to) {
     for (; from < to; from++, to--) {
         let temp = L.stack[from];
-        L.stack[from] = L.stack[to];
+        lobject.setobjs2s(L, from, to);
         L.stack[to] = temp;
     }
 };
@@ -892,7 +892,8 @@ const lua_arith = function(L, op) {
         assert(2 < L.top - L.ci.funcOff, "not enough elements in the stack");  /* all other operations expect two operands */
     else {  /* for unary operations, add fake 2nd operand */
         assert(1 < L.top - L.ci.funcOff, "not enough elements in the stack");
-        L.stack[L.top++] = L.stack[L.top - 1];
+        lobject.setobjs2s(L, L.top, L.top - 1);
+        L.top++;
     }
     /* first operand at top - 2, second at top - 1; result go to top - 2 */
     lobject.luaO_arith(L, op, L.stack[L.top - 2], L.stack[L.top - 1], L.stack[L.top - 2]);
diff --git a/src/ldebug.js b/src/ldebug.js
index 0f387af..0231e67 100644
--- a/src/ldebug.js
+++ b/src/ldebug.js
@@ -155,7 +155,7 @@ const lua_setlocal = function(L, ar, n) {
     let name = local.name;
     let pos = local.pos;
     if (name) {
-        L.stack[pos] = L.stack[L.top - 1];
+        lobject.setobjs2s(L, pos, L.top - 1);
         delete L.stack[--L.top];  /* pop value */
     }
     swapextra(L);
@@ -280,7 +280,8 @@ const lua_getinfo = function(L, what, ar) {
     cl = func.ttisclosure() ? func.value : null;
     status = auxgetinfo(L, what, ar, cl, ci);
     if (what.indexOf('f'.charCodeAt(0)) >= 0) {
-        L.stack[L.top++] = func;
+        lobject.setobjs2s(L, L.top, funcOff);
+        L.top++;
         assert(L.top <= L.ci.top, "stack overflow");
     }
 
@@ -590,8 +591,8 @@ const luaG_runerror = function(L, fmt, ...argp) {
 const luaG_errormsg = function(L) {
     if (L.errfunc !== 0) {  /* is there an error handling function? */
         let errfunc = L.errfunc;
-        L.stack[L.top] = L.stack[L.top - 1];
-        L.stack[L.top - 1] = L.stack[errfunc];
+        lobject.setobjs2s(L, L.top, L.top - 1); /* move argument */
+        lobject.setobjs2s(L, L.top - 1, errfunc); /* push function */
         L.top++;
         ldo.luaD_callnoyield(L, L.top - 2, 1);
     }
diff --git a/src/ldo.js b/src/ldo.js
index 4c198ee..d236968 100644
--- a/src/ldo.js
+++ b/src/ldo.js
@@ -32,7 +32,7 @@ const seterrorobj = function(L, errcode, oldtop) {
             break;
         }
         default: {
-            L.stack[oldtop] = L.stack[L.top - 1];
+            lobject.setobjs2s(L, oldtop, L.top - 1);
         }
     }
 
@@ -186,12 +186,12 @@ const moveresults = function(L, firstResult, res, nres, wanted) {
         case 1: {
             if (nres === 0)
                 L.stack[firstResult] = lobject.luaO_nilobject;
-            L.stack[res] = L.stack[firstResult];
+            lobject.setobjs2s(L, res, firstResult); /* move it to proper place */
             break;
         }
         case defs.LUA_MULTRET: {
             for (let i = 0; i < nres; i++)
-                L.stack[res + i] = L.stack[firstResult + i];
+                lobject.setobjs2s(L, res + i, firstResult + i);
             L.top = res + nres;
             return false;
         }
@@ -199,11 +199,11 @@ const moveresults = function(L, firstResult, res, nres, wanted) {
             let i;
             if (wanted <= nres) {
                 for (i = 0; i < wanted; i++) {
-                    L.stack[res + i] = L.stack[firstResult + i];
+                    lobject.setobjs2s(L, res + i, firstResult + i);
                 }
             } else {
                 for (i = 0; i < nres; i++)
-                    L.stack[res + i] = L.stack[firstResult + i];
+                    lobject.setobjs2s(L, res + i, firstResult + i);
                 for (; i < wanted; i++)
                     L.stack[res + i] = new lobject.TValue(CT.LUA_TNIL, null);
             }
@@ -252,7 +252,7 @@ const adjust_varargs = function(L, p, actual) {
 
     let i;
     for (i = 0; i < nfixargs && i < actual; i++) {
-        L.stack[L.top++] = L.stack[fixed + i];
+        lobject.setobjs2s(L, L.top++, fixed + i);
         L.stack[fixed + i] = new lobject.TValue(CT.LUA_TNIL, null);
     }
 
@@ -268,7 +268,7 @@ const tryfuncTM = function(L, off, func) {
         ldebug.luaG_typeerror(L, func, defs.to_luastring("call", true));
     /* Open a hole inside the stack at 'func' */
     for (let p = L.top; p > off; p--)
-        L.stack[p] = L.stack[p-1];
+        lobject.setobjs2s(L, p, p-1);
     L.top++; /* slot ensured by caller */
     L.stack[off] = new lobject.TValue(tm.type, tm.value); /* tag method is the new function to be called */
 };
@@ -351,8 +351,8 @@ const luaD_rawrunprotected = function(L, f, ud) {
                     /* copy of luaG_errormsg without the throw */
                     if (L.errfunc !== 0) {  /* is there an error handling function? */
                         let errfunc = L.errfunc;
-                        L.stack[L.top] = L.stack[L.top - 1];
-                        L.stack[L.top - 1] = L.stack[errfunc];
+                        lobject.setobjs2s(L, L.top, L.top - 1); /* move argument */
+                        lobject.setobjs2s(L, L.top - 1, errfunc); /* push function */
                         L.top++;
                         luaD_callnoyield(L, L.top - 2, 1);
                     }
diff --git a/src/lobject.js b/src/lobject.js
index b6fd581..7b8a332 100644
--- a/src/lobject.js
+++ b/src/lobject.js
@@ -185,6 +185,11 @@ class TValue {
 
 }
 
+/* from stack to (same) stack */
+const setobjs2s = function(L, newidx, oldidx) {
+    L.stack[newidx] = L.stack[oldidx];
+};
+
 const luaO_nilobject = new TValue(CT.LUA_TNIL, null);
 Object.freeze(luaO_nilobject);
 module.exports.luaO_nilobject = luaO_nilobject;
@@ -667,3 +672,4 @@ module.exports.luaO_tostring     = luaO_tostring;
 module.exports.luaO_utf8desc     = luaO_utf8desc;
 module.exports.luaO_utf8esc      = luaO_utf8esc;
 module.exports.numarith          = numarith;
+module.exports.setobjs2s         = setobjs2s;
diff --git a/src/ltm.js b/src/ltm.js
index ad09c26..041dd19 100644
--- a/src/ltm.js
+++ b/src/ltm.js
@@ -108,7 +108,6 @@ const luaT_objtypename = function(L, o) {
 };
 
 const luaT_callTM = function(L, f, p1, p2, p3, hasres) {
-    let result = p3;
     let func = L.top;
 
     L.stack[L.top] = new lobject.TValue(f.type, f.value); /* push function (assume EXTRA_STACK) */
@@ -124,9 +123,8 @@ const luaT_callTM = function(L, f, p1, p2, p3, hasres) {
     else
         ldo.luaD_callnoyield(L, func, hasres);
 
-    if (hasres) {
-        assert(typeof result === "number");
-        L.stack[result] = L.stack[--L.top];
+    if (hasres) {  /* if has result, move it to its place */
+        lobject.setobjs2s(L, p3, --L.top);
     }
 };
 
diff --git a/src/lvm.js b/src/lvm.js
index 07acb42..602fe5c 100644
--- a/src/lvm.js
+++ b/src/lvm.js
@@ -34,7 +34,7 @@ const luaV_finishOp = function(L) {
         case OCi.OP_MOD: case OCi.OP_POW:
         case OCi.OP_UNM: case OCi.OP_BNOT: case OCi.OP_LEN:
         case OCi.OP_GETTABUP: case OCi.OP_GETTABLE: case OCi.OP_SELF: {
-            L.stack[base + inst.A] = L.stack[--L.top];
+            lobject.setobjs2s(L, base + inst.A, --L.top);
             break;
         }
         case OCi.OP_LE: case OCi.OP_LT: case OCi.OP_EQ: {
@@ -121,7 +121,7 @@ const luaV_execute = function(L) {
 
         switch (opcode) {
             case OCi.OP_MOVE: {
-                L.stack[ra] = L.stack[RB(L, base, i)];
+                lobject.setobjs2s(L, ra, RB(L, base, i));
                 break;
             }
             case OCi.OP_LOADK: {
@@ -197,12 +197,11 @@ const luaV_execute = function(L) {
                 break;
             }
             case OCi.OP_SELF: {
-                let table = L.stack[RB(L, base, i)];
-                let key = RKC(L, base, k, i);
-
-                L.stack[ra + 1] = table;
+                let rb = RB(L, base, i);
+                let rc = RKC(L, base, k, i);
+                lobject.setobjs2s(L, ra + 1, rb);
 
-                gettable(L, table, key, ra);
+                gettable(L, L.stack[rb], rc, ra);
                 break;
             }
             case OCi.OP_ADD: {
@@ -409,7 +408,7 @@ const luaV_execute = function(L) {
                 L.top = base + c + 1; /* mark the end of concat operands */
                 luaV_concat(L, c - b + 1);
                 let rb = base + b;
-                L.stack[ra] = L.stack[rb];
+                lobject.setobjs2s(L, ra, rb);
                 L.top = ci.top; /* restore top */
                 break;
             }
@@ -446,11 +445,12 @@ const luaV_execute = function(L) {
                 break;
             }
             case OCi.OP_TESTSET: {
-                let rb = L.stack[RB(L, base, i)];
+                let rbIdx = RB(L, base, i);
+                let rb = L.stack[rbIdx];
                 if (i.C ? rb.l_isfalse() : !rb.l_isfalse())
                     ci.l_savedpc++;
                 else {
-                    L.stack[ra] = rb;
+                    lobject.setobjs2s(L, ra, rbIdx);
                     donextjump(L, ci);
                 }
                 break;
@@ -485,7 +485,7 @@ const luaV_execute = function(L) {
                     let lim = nci.l_base + nfunc.value.p.numparams;
                     if (cl.p.p.length > 0) lfunc.luaF_close(L, oci.l_base);
                     for (let aux = 0; nfuncOff + aux < lim; aux++)
-                        L.stack[ofuncOff + aux] = L.stack[nfuncOff + aux];
+                        lobject.setobjs2s(L, ofuncOff + aux, nfuncOff + aux);
                     oci.func = nci.func;
                     oci.l_base = ofuncOff + (nci.l_base - nfuncOff);
                     oci.top = L.top = ofuncOff + (L.top - nfuncOff);
@@ -565,9 +565,9 @@ const luaV_execute = function(L) {
             }
             case OCi.OP_TFORCALL: {
                 let cb = ra + 3; /* call base */
-                L.stack[cb + 2] = L.stack[ra + 2];
-                L.stack[cb + 1] = L.stack[ra + 1];
-                L.stack[cb]     = L.stack[ra];
+                lobject.setobjs2s(L, cb+2, ra+2);
+                lobject.setobjs2s(L, cb+1, ra+1);
+                lobject.setobjs2s(L, cb, ra);
                 L.top = cb + 3; /* func. + 2 args (state and index) */
                 ldo.luaD_call(L, cb, i.C);
                 /* go straight to OP_TFORLOOP */
@@ -579,7 +579,7 @@ const luaV_execute = function(L) {
             }
             case OCi.OP_TFORLOOP: {
                 if (!L.stack[ra + 1].ttisnil()) { /* continue loop? */
-                    L.stack[ra] = L.stack[ra + 1]; /* save control variable */
+                    lobject.setobjs2s(L, ra, ra + 1); /* save control variable */
                     ci.l_savedpc += i.sBx; /* jump back */
                 }
                 break;
@@ -625,7 +625,7 @@ const luaV_execute = function(L) {
                 }
 
                 for (j = 0; j < b && j < n; j++)
-                    L.stack[ra + j] = L.stack[base - n + j];
+                    lobject.setobjs2s(L, ra + j, base - n + j);
 
                 for (; j < b; j++) /* complete required results with nil */
                     L.stack[ra + j] = new lobject.TValue(CT.LUA_TNIL, null);
@@ -996,7 +996,7 @@ const luaV_concat = function(L, total) {
             tostring(L, top - 2);
             delete L.stack[top - 1];
         } else if (isemptystr(L.stack[top-2])) {
-            L.stack[top - 2] = L.stack[top - 1];
+            lobject.setobjs2s(L, top - 2, top - 1);
             delete L.stack[top - 1];
         } else {
             /* at least two non-empty string values; get as many as possible */