From 58453dc1e1cb8c77f91cb858ec9b475a945f7f3c Mon Sep 17 00:00:00 2001
From: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Mon, 14 Aug 2000 14:46:27 -0300
Subject: [PATCH] small bug in symbolic execution

---
 lcode.c   |  5 +++--
 ldebug.c  | 37 ++++++++++++++++++++++---------------
 lparser.c |  5 +++--
 3 files changed, 28 insertions(+), 19 deletions(-)

diff --git a/lcode.c b/lcode.c
index 33236931..bd0d2612 100644
--- a/lcode.c
+++ b/lcode.c
@@ -1,5 +1,5 @@
 /*
-** $Id: lcode.c,v 1.46 2000/08/09 19:16:57 roberto Exp roberto $
+** $Id: lcode.c,v 1.47 2000/08/10 19:50:47 roberto Exp roberto $
 ** Code generator for Lua
 ** See Copyright Notice in lua.h
 */
@@ -330,7 +330,8 @@ void luaK_tostack (LexState *ls, expdesc *v, int onlyone) {
           luaK_concat(fs, &v->u.l.t, fs->pc-1);  /* put `previous' in t. list */
         else {
           j = code_label(fs, OP_JMP, NO_JUMP);  /* to jump over both pushes */
-          luaK_deltastack(fs, -1);  /* next PUSHes may be skipped */
+          /* correct stack for compiler and simbolic execution */
+          luaK_adjuststack(fs, 1);
         }
         p_nil = code_label(fs, OP_PUSHNILJMP, 0);
         p_1 = code_label(fs, OP_PUSHINT, 1);
diff --git a/ldebug.c b/ldebug.c
index e0b3925a..136afc5a 100644
--- a/ldebug.c
+++ b/ldebug.c
@@ -1,5 +1,5 @@
 /*
-** $Id: ldebug.c,v 1.32 2000/08/10 19:50:47 roberto Exp roberto $
+** $Id: ldebug.c,v 1.33 2000/08/11 16:17:28 roberto Exp roberto $
 ** Debug Interface
 ** See Copyright Notice in lua.h
 */
@@ -296,11 +296,15 @@ static Instruction luaG_symbexec (const Proto *pt, int lastpc, int stackpos) {
     const Instruction i = code[pc++];
     LUA_ASSERT(0 <= top && top <= pt->maxstacksize, "wrong stack");
     switch (GET_OPCODE(i)) {
-      case OP_RETURN:
-      case OP_TAILCALL:
-      case OP_END: {
-        LUA_INTERNALERROR("invalid symbolic run");
-        return CREATE_0(OP_END);  /* stop execution */
+      case OP_RETURN: {
+        LUA_ASSERT(top >= GETARG_U(i), "wrong stack");
+        top = GETARG_U(i);
+        break;
+      }
+      case OP_TAILCALL: {
+        LUA_ASSERT(top >= GETARG_A(i), "wrong stack");
+        top = GETARG_B(i);
+        break;
       }
       case OP_CALL: {
         int nresults = GETARG_B(i);
@@ -336,6 +340,18 @@ static Instruction luaG_symbexec (const Proto *pt, int lastpc, int stackpos) {
         stack[top++] = pc-1;
         break;
       }
+      case OP_JMPONT:
+      case OP_JMPONF: {
+        int newpc = pc + GETARG_S(i);
+        /* jump is forward and do not skip `lastpc'? */
+        if (pc < newpc && newpc <= lastpc) {
+          stack[top-1] = pc-1;  /* value comes from `and'/`or' */
+          pc = newpc;  /* do the jump */
+        }
+        else
+          top--;  /* do not jump; pop value */
+        break;
+      }
       default: {
         OpCode op = GET_OPCODE(i);
         LUA_ASSERT(luaK_opproperties[op].push != VD,
@@ -343,15 +359,6 @@ static Instruction luaG_symbexec (const Proto *pt, int lastpc, int stackpos) {
         top -= luaK_opproperties[op].pop;
         LUA_ASSERT(top >= 0, "wrong stack");
         top = pushpc(stack, pc, top, luaK_opproperties[op].push);
-        if (ISJUMP(op)) {
-          int newpc = pc + GETARG_S(i);
-          /* jump is forward and do not skip `lastpc'? */
-          if (pc < newpc && newpc <= lastpc) {
-            if (op == OP_JMPONT || op == OP_JMPONF)
-              stack[top++] = pc-1;  /* do not pop when jumping */
-            pc = newpc;  /* do the jump */
-          }
-        }
       }
     }
   }
diff --git a/lparser.c b/lparser.c
index ef4a57ab..cc9a6c9a 100644
--- a/lparser.c
+++ b/lparser.c
@@ -1,5 +1,5 @@
 /*
-** $Id: lparser.c,v 1.106 2000/08/09 14:49:13 roberto Exp roberto $
+** $Id: lparser.c,v 1.107 2000/08/09 19:16:57 roberto Exp roberto $
 ** LL(1) Parser and code generator for Lua
 ** See Copyright Notice in lua.h
 */
@@ -1024,7 +1024,8 @@ static void breakstat (LexState *ls) {
   next(ls);  /* skip BREAK */
   luaK_adjuststack(fs, currentlevel - bl->stacklevel);
   luaK_concat(fs, &bl->breaklist, luaK_jump(fs));
-  fs->stacklevel = currentlevel;
+  /* correct stack for compiler and simbolic execution */
+  luaK_adjuststack(fs, bl->stacklevel - currentlevel);
 }