commit a8f8c7fd80a5c7e630fd4bf7f858d05024f6b434
parent 1a19893d6f8ee16944168a3f2c99002f70522f4c
Author: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Mon, 16 Dec 2013 12:29:57 -0200
integer exponentiation with negative exponent is invalid
Diffstat:
4 files changed, 32 insertions(+), 30 deletions(-)
diff --git a/lcode.c b/lcode.c
@@ -1,5 +1,5 @@
/*
-** $Id: lcode.c,v 2.71 2013/06/25 18:57:18 roberto Exp roberto $
+** $Id: lcode.c,v 2.72 2013/08/30 16:01:37 roberto Exp roberto $
** Code generator for Lua
** See Copyright Notice in lua.h
*/
@@ -754,12 +754,14 @@ static int constfolding (OpCode op, expdesc *e1, expdesc *e2) {
TValue v1, v2, res;
lua_Integer i;
if (!tonumeral(e1, &v1) || !tonumeral(e2, &v2))
- return 0;
+ return 0; /* non-numeric operands */
if (op == OP_IDIV &&
(!tointeger(&v1, &i) || !tointeger(&v2, &i) || i == 0))
return 0; /* avoid division by 0 and conversion errors */
- if (op == OP_MOD && ttisinteger(&v1) && ttisinteger(&v2) && ivalue(&v2) == 0)
- return 0; /* avoid module by 0 at compile time */
+ if (ttisinteger(&v1) && ttisinteger(&v2) && /* for integer operations... */
+ ((op == OP_MOD && ivalue(&v2) == 0) || /* ...avoid module by 0... */
+ (op == OP_POW && ivalue(&v2) < 0))) /* ...and negative exponents */
+ return 0;
luaO_arith(NULL, op - OP_ADD + LUA_OPADD, &v1, &v2, &res);
if (ttisinteger(&res)) {
e1->k = VKINT;
diff --git a/lobject.c b/lobject.c
@@ -1,5 +1,5 @@
/*
-** $Id: lobject.c,v 2.67 2013/06/25 18:58:32 roberto Exp roberto $
+** $Id: lobject.c,v 2.68 2013/07/10 17:15:12 roberto Exp roberto $
** Some generic functions over Lua objects
** See Copyright Notice in lua.h
*/
@@ -77,7 +77,7 @@ static lua_Integer intarith (lua_State *L, int op, lua_Integer v1,
case LUA_OPSUB:return intop(-, v1, v2);
case LUA_OPMUL:return intop(*, v1, v2);
case LUA_OPMOD: return luaV_mod(L, v1, v2);
- case LUA_OPPOW: return luaV_pow(v1, v2);
+ case LUA_OPPOW: return luaV_pow(L, v1, v2);
case LUA_OPUNM: return intop(-, 0, v1);
default: lua_assert(0); return 0;
}
@@ -110,8 +110,7 @@ void luaO_arith (lua_State *L, int op, const TValue *p1, const TValue *p2,
}
else { /* other operations */
lua_Number n1; lua_Number n2;
- if (ttisinteger(p1) && ttisinteger(p2) && op != LUA_OPDIV &&
- (op != LUA_OPPOW || ivalue(p2) >= 0)) {
+ if (ttisinteger(p1) && ttisinteger(p2) && op != LUA_OPDIV) {
setivalue(res, intarith(L, op, ivalue(p1), ivalue(p2)));
return;
}
@@ -122,7 +121,7 @@ void luaO_arith (lua_State *L, int op, const TValue *p1, const TValue *p2,
/* else go to the end */
}
/* could not perform raw operation; try metmethod */
- lua_assert(L != NULL); /* cannot fail when folding (compile time) */
+ lua_assert(L != NULL); /* should not fail when folding (compile time) */
luaT_trybinTM(L, p1, p2, res, cast(TMS, op - LUA_OPADD + TM_ADD));
}
diff --git a/lvm.c b/lvm.c
@@ -1,5 +1,5 @@
/*
-** $Id: lvm.c,v 2.179 2013/08/27 18:53:35 roberto Exp roberto $
+** $Id: lvm.c,v 2.180 2013/08/29 13:49:57 roberto Exp roberto $
** Lua virtual machine
** See Copyright Notice in lua.h
*/
@@ -333,8 +333,7 @@ lua_Integer luaV_div (lua_State *L, lua_Integer x, lua_Integer y) {
if (cast_unsigned(y) + 1 <= 1U) { /* special cases: -1 or 0 */
if (y == 0)
luaG_runerror(L, "attempt to divide by zero");
- else /* -1 */
- return intop(-, 0, x); /* avoid overflow with 0x80000... */
+ return intop(-, 0, x); /* y==-1; avoid overflow with 0x80000...//-1 */
}
else {
lua_Integer d = x / y; /* perform division */
@@ -350,8 +349,7 @@ lua_Integer luaV_mod (lua_State *L, lua_Integer x, lua_Integer y) {
if (cast_unsigned(y) + 1 <= 1U) { /* special cases: -1 or 0 */
if (y == 0)
luaG_runerror(L, "attempt to perform 'n%%0'");
- else /* -1 */
- return 0; /* avoid overflow with 0x80000... */
+ return 0; /* y==-1; avoid overflow with 0x80000...%-1 */
}
else {
lua_Integer r = x % y;
@@ -363,16 +361,21 @@ lua_Integer luaV_mod (lua_State *L, lua_Integer x, lua_Integer y) {
}
-lua_Integer luaV_pow (lua_Integer x, lua_Integer y) {
- lua_Integer r = 1;
- lua_assert(y >= 0);
- if (y == 0) return r;
- for (; y > 1; y >>= 1) {
- if (y & 1) r = intop(*, r, x);
- x = intop(*, x, x);
+lua_Integer luaV_pow (lua_State *L, lua_Integer x, lua_Integer y) {
+ if (y <= 0) { /* special cases: 0 or negative exponent */
+ if (y < 0)
+ luaG_runerror(L, "integer exponentiation with negative exponent");
+ return 1; /* x^0 == 1 */
+ }
+ else {
+ lua_Integer r = 1;
+ for (; y > 1; y >>= 1) {
+ if (y & 1) r = intop(*, r, x);
+ x = intop(*, x, x);
+ }
+ r = intop(*, r, x);
+ return r;
}
- r = intop(*, r, x);
- return r;
}
@@ -685,11 +688,9 @@ void luaV_execute (lua_State *L) {
TValue *rb = RKB(i);
TValue *rc = RKC(i);
lua_Number nb; lua_Number nc;
- lua_Integer ic;
- if (ttisinteger(rb) && ttisinteger(rc) &&
- (ic = ivalue(rc)) >= 0) {
- lua_Integer ib = ivalue(rb);
- setivalue(ra, luaV_pow(ib, ic));
+ if (ttisinteger(rb) && ttisinteger(rc)) {
+ lua_Integer ib = ivalue(rb); lua_Integer ic = ivalue(rc);
+ setivalue(ra, luaV_pow(L, ib, ic));
}
else if (tonumber(rb, &nb) && tonumber(rc, &nc)) {
setnvalue(ra, luai_numpow(L, nb, nc));
diff --git a/lvm.h b/lvm.h
@@ -1,5 +1,5 @@
/*
-** $Id: lvm.h,v 2.22 2013/04/29 17:12:50 roberto Exp roberto $
+** $Id: lvm.h,v 2.23 2013/05/02 12:31:26 roberto Exp roberto $
** Lua virtual machine
** See Copyright Notice in lua.h
*/
@@ -43,7 +43,7 @@ LUAI_FUNC void luaV_execute (lua_State *L);
LUAI_FUNC void luaV_concat (lua_State *L, int total);
LUAI_FUNC lua_Integer luaV_div (lua_State *L, lua_Integer x, lua_Integer y);
LUAI_FUNC lua_Integer luaV_mod (lua_State *L, lua_Integer x, lua_Integer y);
-LUAI_FUNC lua_Integer luaV_pow (lua_Integer x, lua_Integer y);
+LUAI_FUNC lua_Integer luaV_pow (lua_State *L, lua_Integer x, lua_Integer y);
LUAI_FUNC void luaV_objlen (lua_State *L, StkId ra, const TValue *rb);
#endif
