From d6af81084df569bc8e3bd0949ad6fc0b40c8468d Mon Sep 17 00:00:00 2001
From: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Wed, 17 Jul 2019 14:26:56 -0300
Subject: New kind of expression VKSTR

String literal expressions have their own kind VKSTR, instead of the
generic VK. This allows strings to "cross" functions without entering
their constant tables (e.g., if they are used only by some nested
function).
---
 lcode.c | 35 +++++++++++++++++++++++++----------
 1 file changed, 25 insertions(+), 10 deletions(-)

(limited to 'lcode.c')

diff --git a/lcode.c b/lcode.c
index e57ad284..40efcff3 100644
--- a/lcode.c
+++ b/lcode.c
@@ -81,9 +81,8 @@ int luaK_exp2const (FuncState *fs, const expdesc *e, TValue *v) {
     case VNIL:
       setnilvalue(v);
       return 1;
-    case VK: {
-      TValue *k = &fs->f->k[e->u.info];
-      setobj(fs->ls->L, v, k);
+    case VKSTR: {
+      setsvalue(fs->ls->L, v, e->u.strval);
       return 1;
     }
     default: return tonumeral(e, v);
@@ -561,7 +560,7 @@ static int addk (FuncState *fs, TValue *key, TValue *v) {
 /*
 ** Add a string to list of constants and return its index.
 */
-int luaK_stringK (FuncState *fs, TString *s) {
+static int stringK (FuncState *fs, TString *s) {
   TValue o;
   setsvalue(fs->ls->L, &o, s);
   return addk(fs, &o, &o);  /* use string itself as key */
@@ -656,7 +655,7 @@ static void luaK_float (FuncState *fs, int reg, lua_Number f) {
 /*
 ** Convert a constant in 'v' into an expression description 'e'
 */
-static void const2exp (FuncState *fs, TValue *v, expdesc *e) {
+static void const2exp (TValue *v, expdesc *e) {
   switch (ttypetag(v)) {
     case LUA_TNUMINT:
       e->k = VKINT; e->u.ival = ivalue(v);
@@ -671,7 +670,7 @@ static void const2exp (FuncState *fs, TValue *v, expdesc *e) {
       e->k = VNIL;
       break;
     case LUA_TSHRSTR:  case LUA_TLNGSTR:
-      e->k = VK; e->u.info = luaK_stringK(fs, tsvalue(v));
+      e->k = VKSTR; e->u.strval = tsvalue(v);
       break;
     default: lua_assert(0);
   }
@@ -696,6 +695,16 @@ void luaK_setreturns (FuncState *fs, expdesc *e, int nresults) {
 }
 
 
+/*
+** Convert a VKSTR to a VK
+*/
+static void str2K (FuncState *fs, expdesc *e) {
+  lua_assert(e->k == VKSTR);
+  e->u.info = stringK(fs, e->u.strval);
+  e->k = VK;
+}
+
+
 /*
 ** Fix an expression to return one result.
 ** If expression is not a multi-ret expression (function call or
@@ -728,7 +737,7 @@ void luaK_dischargevars (FuncState *fs, expdesc *e) {
   switch (e->k) {
     case VCONST: {
       TValue *val = &fs->ls->dyd->actvar.arr[e->u.info].k;
-      const2exp(fs, val, e);
+      const2exp(val, e);
       break;
     }
     case VLOCAL: {  /* already in a register */
@@ -789,6 +798,9 @@ static void discharge2reg (FuncState *fs, expdesc *e, int reg) {
       luaK_codeABC(fs, OP_LOADBOOL, reg, e->k == VTRUE, 0);
       break;
     }
+    case VKSTR: {
+      str2K(fs, e);
+    }  /* FALLTHROUGH */
     case VK: {
       luaK_codek(fs, reg, e->u.info);
       break;
@@ -949,6 +961,7 @@ static int luaK_exp2K (FuncState *fs, expdesc *e) {
       case VNIL: info = nilK(fs); break;
       case VKINT: info = luaK_intK(fs, e->u.ival); break;
       case VKFLT: info = luaK_numberK(fs, e->u.nval); break;
+      case VKSTR: info = stringK(fs, e->u.strval); break;
       case VK: info = e->u.info; break;
       default: return 0;  /* not a constant */
     }
@@ -1083,7 +1096,7 @@ void luaK_goiftrue (FuncState *fs, expdesc *e) {
       pc = e->u.info;  /* save jump position */
       break;
     }
-    case VK: case VKFLT: case VKINT: case VTRUE: {
+    case VK: case VKFLT: case VKINT: case VKSTR: case VTRUE: {
       pc = NO_JUMP;  /* always true; do nothing */
       break;
     }
@@ -1133,7 +1146,7 @@ static void codenot (FuncState *fs, expdesc *e) {
       e->k = VTRUE;  /* true == not nil == not false */
       break;
     }
-    case VK: case VKFLT: case VKINT: case VTRUE: {
+    case VK: case VKFLT: case VKINT: case VKSTR: case VTRUE: {
       e->k = VFALSE;  /* false == not "x" == not 0.5 == not 1 == not true */
       break;
     }
@@ -1219,9 +1232,11 @@ static int isSCnumber (expdesc *e, lua_Integer *i, int *isfloat) {
 ** values in registers.
 */
 void luaK_indexed (FuncState *fs, expdesc *t, expdesc *k) {
+  if (k->k == VKSTR)
+    str2K(fs, k);
   lua_assert(!hasjumps(t) &&
              (t->k == VLOCAL || t->k == VNONRELOC || t->k == VUPVAL));
-  if (t->k == VUPVAL && !isKstr(fs, k))  /* upvalue indexed by non string? */
+  if (t->k == VUPVAL && !isKstr(fs, k))  /* upvalue indexed by non 'Kstr'? */
     luaK_exp2anyreg(fs, t);  /* put it in a register */
   if (t->k == VUPVAL) {
     t->u.ind.t = t->u.info;  /* upvalue index */
-- 
cgit v1.2.3-55-g6feb