From 9b7987a9d1471ba94764286b28e0998f73deb46a Mon Sep 17 00:00:00 2001
From: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Tue, 11 Feb 2020 11:12:33 -0300
Subject: [PATCH] OP_LOADFALSE broken in two instructions

---
 lcode.c    | 8 ++++----
 ljumptab.h | 1 +
 lopcodes.c | 1 +
 lopcodes.h | 3 ++-
 lopnames.h | 1 +
 lvm.c      | 6 +++++-
 6 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/lcode.c b/lcode.c
index 332fdd00..35e0527f 100644
--- a/lcode.c
+++ b/lcode.c
@@ -872,9 +872,9 @@ static void discharge2anyreg (FuncState *fs, expdesc *e) {
 }
 
 
-static int code_loadbool (FuncState *fs, int A, OpCode op, int jump) {
+static int code_loadbool (FuncState *fs, int A, OpCode op) {
   luaK_getlabel(fs);  /* those instructions may be jump targets */
-  return luaK_codeABC(fs, op, A, jump, 0);
+  return luaK_codeABC(fs, op, A, 0, 0);
 }
 
 
@@ -908,8 +908,8 @@ static void exp2reg (FuncState *fs, expdesc *e, int reg) {
     int p_t = NO_JUMP;  /* position of an eventual LOAD true */
     if (need_value(fs, e->t) || need_value(fs, e->f)) {
       int fj = (e->k == VJMP) ? NO_JUMP : luaK_jump(fs);
-      p_f = code_loadbool(fs, reg, OP_LOADFALSE, 1);  /* skip next inst. */
-      p_t = code_loadbool(fs, reg, OP_LOADTRUE, 0);
+      p_f = code_loadbool(fs, reg, OP_LFALSESKIP);  /* skip next inst. */
+      p_t = code_loadbool(fs, reg, OP_LOADTRUE);
       /* jump around these booleans if 'e' is not a test */
       luaK_patchtohere(fs, fj);
     }
diff --git a/ljumptab.h b/ljumptab.h
index 22e9575f..0edd79d5 100644
--- a/ljumptab.h
+++ b/ljumptab.h
@@ -31,6 +31,7 @@ static void *disptab[NUM_OPCODES] = {
 &&L_OP_LOADK,
 &&L_OP_LOADKX,
 &&L_OP_LOADFALSE,
+&&L_OP_LFALSESKIP,
 &&L_OP_LOADTRUE,
 &&L_OP_LOADNIL,
 &&L_OP_GETUPVAL,
diff --git a/lopcodes.c b/lopcodes.c
index f5347a3c..4e983e08 100644
--- a/lopcodes.c
+++ b/lopcodes.c
@@ -25,6 +25,7 @@ LUAI_DDEF const lu_byte luaP_opmodes[NUM_OPCODES] = {
  ,opmode(0, 0, 0, 0, 1, iABx)		/* OP_LOADK */
  ,opmode(0, 0, 0, 0, 1, iABx)		/* OP_LOADKX */
  ,opmode(0, 0, 0, 0, 1, iABC)		/* OP_LOADFALSE */
+ ,opmode(0, 0, 0, 0, 1, iABC)		/* OP_LFALSESKIP */
  ,opmode(0, 0, 0, 0, 1, iABC)		/* OP_LOADTRUE */
  ,opmode(0, 0, 0, 0, 1, iABC)		/* OP_LOADNIL */
  ,opmode(0, 0, 0, 0, 1, iABC)		/* OP_GETUPVAL */
diff --git a/lopcodes.h b/lopcodes.h
index 8fd52d18..d755870f 100644
--- a/lopcodes.h
+++ b/lopcodes.h
@@ -202,7 +202,8 @@ OP_LOADI,/*	A sBx	R[A] := sBx					*/
 OP_LOADF,/*	A sBx	R[A] := (lua_Number)sBx				*/
 OP_LOADK,/*	A Bx	R[A] := K[Bx]					*/
 OP_LOADKX,/*	A 	R[A] := K[extra arg]				*/
-OP_LOADFALSE,/*	A B	R[A] := false; if (B) pc++			*/
+OP_LOADFALSE,/*	A  	R[A] := false					*/
+OP_LFALSESKIP,/*A 	R[A] := false; pc++				*/
 OP_LOADTRUE,/*	A	R[A] := true					*/
 OP_LOADNIL,/*	A B	R[A], R[A+1], ..., R[A+B] := nil		*/
 OP_GETUPVAL,/*	A B	R[A] := UpValue[B]				*/
diff --git a/lopnames.h b/lopnames.h
index a2097a74..f20147e3 100644
--- a/lopnames.h
+++ b/lopnames.h
@@ -16,6 +16,7 @@ static const char *const opnames[] = {
   "LOADK",
   "LOADKX",
   "LOADFALSE",
+  "LFALSESKIP",
   "LOADTRUE",
   "LOADNIL",
   "GETUPVAL",
diff --git a/lvm.c b/lvm.c
index 9c1ad47e..d802379c 100644
--- a/lvm.c
+++ b/lvm.c
@@ -1183,7 +1183,11 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
       }
       vmcase(OP_LOADFALSE) {
         setbfvalue(s2v(ra));
-        if (GETARG_B(i)) pc++;  /* if B, skip next instruction */
+        vmbreak;
+      }
+      vmcase(OP_LFALSESKIP) {
+        setbfvalue(s2v(ra));
+        pc++;  /* skip next instruction */
         vmbreak;
       }
       vmcase(OP_LOADTRUE) {