Have lua closures point to directly to their upvalues on stack

4 files changed, 31 insertions, 40 deletions

diff --git a/src/lapi.js b/src/lapi.js
index f24c4af..529a009 100644
--- a/src/lapi.js
+++ b/src/lapi.js
@@ -538,7 +538,7 @@ const aux_upvalue = function(L, fi, n) {
             let name = p.upvalues[n-1].name;
             return {
                 name: name ? name.getstr() : defs.to_luastring("(*no name)", true),
-                val: f.upvals[n-1].val()
+                val: f.upvals[n-1].v
             };
         }
         default: return null;  /* not a closure */
@@ -926,7 +926,7 @@ const lua_load = function(L, reader, data, chunkname, mode) {
             /* get global table from registry */
             let gt = ltable.luaH_getint(L.l_G.l_registry.value, defs.LUA_RIDX_GLOBALS);
             /* set global table as 1st upvalue of 'f' (may be LUA_ENV) */
-            f.upvals[0].value.setfrom(gt);
+            f.upvals[0].v.setfrom(gt);
         }
     }
     return status;
diff --git a/src/ldebug.js b/src/ldebug.js
index 45d126f..510221f 100644
--- a/src/ldebug.js
+++ b/src/ldebug.js
@@ -518,7 +518,7 @@ const isinstack = function(L, ci, o) {
 const getupvalname = function(L, ci, o) {
     let c = ci.func.value;
     for (let i = 0; i < c.nupvalues; i++) {
-        if (c.upvals[i].val() === o) {
+        if (c.upvals[i].v === o) {
             return {
                 name: upvalname(c.p, i),
                 funcname: defs.to_luastring('upvalue', true)
diff --git a/src/lfunc.js b/src/lfunc.js
index 663f614..97e5f02 100644
--- a/src/lfunc.js
+++ b/src/lfunc.js
@@ -30,19 +30,14 @@ class Proto {
 class UpVal {
 
     constructor() {
-        this.L = null; /* Keep track of the thread it comes from */
-        this.v = null; /* if open: stack index. if closed: null (find it in this.value) */
-        this.open_next = null; /* linked list (when open) */
+        this.v = void 0; /* if open: reference to TValue on stack. if closed: TValue */
+        this.vOff = void 0; /* if open: index on stack. if closed: undefined */
         this.refcount = 0;
-        this.value = null; /* the TValue (when closed) */
-    }
-
-    val() {
-        return this.v !== null ? this.L.stack[this.v] : this.value;
+        this.open_next = null; /* linked list (when open) */
     }
 
     isopen() {
-        return this.v !== null;
+        return this.vOff !== void 0;
     }
 
 }
@@ -56,9 +51,9 @@ const luaF_newLclosure = function(L, n) {
 const luaF_findupval = function(L, level) {
     let prevp;
     let p = L.openupval;
-    while (p !== null && p.v >= level) {
+    while (p !== null && p.vOff >= level) {
         assert(p.isopen());
-        if (p.v === level) /* found a corresponding upvalue? */
+        if (p.vOff === level) /* found a corresponding upvalue? */
             return p; /* return it */
         prevp = p;
         p = p.open_next;
@@ -71,23 +66,25 @@ const luaF_findupval = function(L, level) {
         prevp.open_next = uv;
     else
         L.openupval = uv;
-    /* current value lives in the stack */
-    uv.L = L;
-    uv.v = level;
+    uv.v = L.stack[level]; /* current value lives in the stack */
+    uv.vOff = level;
     return uv;
 };
 
 const luaF_close = function(L, level) {
-    while (L.openupval !== null && L.openupval.v >= level) {
+    while (L.openupval !== null && L.openupval.vOff >= level) {
         let uv = L.openupval;
         assert(uv.isopen());
         L.openupval = uv.open_next; /* remove from 'open' list */
-        if (uv.refcount > 0) {
-            let from = uv.L.stack[uv.v];
-            uv.L = null;
-            uv.v = null;
-            uv.value = new lobject.TValue(from.type, from.value);
+        if (uv.refcount === 0) { /* no references? */
+            /* free upvalue */
+            uv.v = void 0;
+            uv.open_next = null;
+        } else {
+            let from = uv.v;
+            uv.v = new lobject.TValue(from.type, from.value);
         }
+        uv.vOff = void 0;
     }
 };
 
@@ -98,7 +95,7 @@ const luaF_initupvals = function(L, cl) {
     for (let i = 0; i < cl.nupvalues; i++) {
         let uv = new UpVal(L);
         uv.refcount = 1;
-        uv.value = new lobject.TValue(CT.LUA_TNIL, null);
+        uv.v = new lobject.TValue(CT.LUA_TNIL, null);
         cl.upvals[i] = uv;
     }
 };
diff --git a/src/lvm.js b/src/lvm.js
index af8984f..b7b1358 100644
--- a/src/lvm.js
+++ b/src/lvm.js
@@ -171,32 +171,26 @@ const luaV_execute = function(L) {
                 break;
             }
             case OCi.OP_GETUPVAL: {
-                let o = cl.upvals[i.B].val();
-                lobject.setobj2s(L, ra, o);
+                let b = i.B;
+                lobject.setobj2s(L, ra, cl.upvals[b].v);
                 break;
             }
             case OCi.OP_SETUPVAL: {
                 let uv = cl.upvals[i.B];
-                if (uv.isopen()) {
-                    uv.L.stack[uv.v].setfrom(L.stack[ra]);
-                } else {
-                    uv.value.setfrom(L.stack[ra]);
-                }
+                uv.v.setfrom(L.stack[ra]);
                 break;
             }
             case OCi.OP_GETTABUP: {
-                let table = cl.upvals[i.B].val();
-                let key = RKC(L, base, k, i);
-
-                gettable(L, table, key, ra);
+                let upval = cl.upvals[i.B].v;
+                let rc = RKC(L, base, k, i);
+                gettable(L, upval, rc, ra);
                 break;
             }
             case OCi.OP_SETTABUP: {
-                let table = cl.upvals[i.A].val();
-                let key = RKB(L, base, k, i);
-                let v = RKC(L, base, k, i);
-
-                settable(L, table, key, v);
+                let upval = cl.upvals[i.A].v;
+                let rb = RKB(L, base, k, i);
+                let rc = RKC(L, base, k, i);
+                settable(L, upval, rb, rc);
                 break;
             }
             case OCi.OP_GETTABLE: {