From 57f8414de1968b6f9f212140f2da14cba3b6dacb Mon Sep 17 00:00:00 2001
From: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Wed, 27 May 2009 14:11:27 -0300
Subject: small bug in 'luaV_concat' (L->top was left incorrect in some cases)
---
lvm.c | 43 ++++++++++++++++++++++---------------------
1 file changed, 22 insertions(+), 21 deletions(-)
(limited to 'lvm.c')
diff --git a/lvm.c b/lvm.c
index a6207984..9842bcb9 100644
--- a/lvm.c
+++ b/lvm.c
@@ -1,5 +1,5 @@
/*
-** $Id: lvm.c,v 2.87 2009/04/30 17:42:21 roberto Exp roberto $
+** $Id: lvm.c,v 2.88 2009/05/22 15:19:54 roberto Exp $
** Lua virtual machine
** See Copyright Notice in lua.h
*/
@@ -264,24 +264,22 @@ int luaV_equalval_ (lua_State *L, const TValue *t1, const TValue *t2) {
}
-void luaV_concat (lua_State *L, int total, int last) {
+void luaV_concat (lua_State *L, int total) {
+ lua_assert(total >= 2);
do {
- StkId top = L->base + last + 1;
+ StkId top = L->top;
int n = 2; /* number of elements handled in this pass (at least 2) */
if (!(ttisstring(top-2) || ttisnumber(top-2)) || !tostring(L, top-1)) {
- L->top = top; /* set top to current position (in case of yield) */
if (!call_binTM(L, top-2, top-1, top-2, TM_CONCAT))
luaG_concaterror(L, top-2, top-1);
- L->top = L->ci->top; /* restore top */
- }
- else if (tsvalue(top-1)->len == 0) { /* second operand is empty? */
- (void)tostring(L, top - 2); /* result is first operand */ ;
}
+ else if (tsvalue(top-1)->len == 0) /* second operand is empty? */
+ (void)tostring(L, top - 2); /* result is first operand */
else if (ttisstring(top-2) && tsvalue(top-2)->len == 0) {
- setsvalue2s(L, top-2, rawtsvalue(top-1)); /* result is second op. */
+ setsvalue2s(L, top-2, rawtsvalue(top-1)); /* result is second op. */
}
else {
- /* at least two (non-empty) string values; get as many as possible */
+ /* at least two non-empty string values; get as many as possible */
size_t tl = tsvalue(top-1)->len;
char *buffer;
int i;
@@ -300,8 +298,8 @@ void luaV_concat (lua_State *L, int total, int last) {
}
setsvalue2s(L, top-n, luaS_newlstr(L, buffer, tl));
}
- total -= n-1; /* got `n' strings to create 1 new */
- last -= n-1;
+ total -= n-1; /* got 'n' strings to create 1 new */
+ L->top -= n-1; /* poped 'n' strings and pushed one */
} while (total > 1); /* repeat until only 1 result left */
}
@@ -381,16 +379,17 @@ void luaV_finishOp (lua_State *L) {
break;
}
case OP_CONCAT: {
- StkId top = L->top - 1; /* top when __concat was called */
- int last = cast_int(top - ci->base) - 2; /* last element and ... */
- int b = GETARG_B(inst); /* ... first element to concatenate */
- int total = last - b + 1; /* number of elements to concatenate */
+ StkId top = L->top - 1; /* top when 'call_binTM' was called */
+ int b = GETARG_B(inst); /* first element to concatenate */
+ int total = top - 1 - (ci->base + b); /* elements yet to concatenate */
setobj2s(L, top - 2, top); /* put TM result in proper position */
- L->top = ci->top; /* correct top */
- if (total > 1) /* are there elements to concat? */
- luaV_concat(L, total, last); /* concat them (may yield again) */
+ if (total > 1) { /* are there elements to concat? */
+ L->top = top - 1; /* top is one after last element (at top-2) */
+ luaV_concat(L, total); /* concat them (may yield again) */
+ }
/* move final result to final position */
- setobj2s(L, ci->base + GETARG_A(inst), ci->base + b);
+ setobj2s(L, ci->base + GETARG_A(inst), L->top - 1);
+ L->top = ci->top; /* restore top */
break;
}
case OP_TFORCALL: {
@@ -586,7 +585,9 @@ void luaV_execute (lua_State *L) {
case OP_CONCAT: {
int b = GETARG_B(i);
int c = GETARG_C(i);
- Protect(luaV_concat(L, c-b+1, c); luaC_checkGC(L));
+ L->top = base + c + 1; /* mark the end of concat operands */
+ Protect(luaV_concat(L, c-b+1); luaC_checkGC(L));
+ L->top = ci->top; /* restore top */
setobjs2s(L, RA(i), base+b);
continue;
}
--
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