commit ab0a851db438c4dd50b76bcf624c15623cc057e4
parent 728ff9459579894ef7fd861c90be6247831799be
Author: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Wed, 10 Jan 2018 17:19:00 -0200
'luaD_tryfuncTM' can ensure it does not change the stack
Diffstat:
3 files changed, 8 insertions(+), 13 deletions(-)
diff --git a/ldo.c b/ldo.c
@@ -1,5 +1,5 @@
/*
-** $Id: ldo.c,v 2.184 2017/12/28 14:17:09 roberto Exp roberto $
+** $Id: ldo.c,v 2.185 2017/12/29 15:44:51 roberto Exp roberto $
** Stack and Call structure of Lua
** See Copyright Notice in lua.h
*/
@@ -327,18 +327,15 @@ static void rethook (lua_State *L, CallInfo *ci) {
** it in stack below original 'func' so that 'luaD_call' can call
** it. Raise an error if __call metafield is not a function.
*/
-StkId luaD_tryfuncTM (lua_State *L, StkId func) {
+void luaD_tryfuncTM (lua_State *L, StkId func) {
const TValue *tm = luaT_gettmbyobj(L, s2v(func), TM_CALL);
StkId p;
if (!ttisfunction(tm))
luaG_typeerror(L, s2v(func), "call");
- /* Open a hole inside the stack at 'func' */
- checkstackp(L, 1, func); /* ensure space for metamethod */
for (p = L->top; p > func; p--)
setobjs2s(L, p, p-1);
- L->top++;
+ L->top++; /* assume EXTRA_STACK */
setobj2s(L, func, tm); /* metamethod is the new function to be called */
- return func;
}
@@ -489,7 +486,7 @@ void luaD_call (lua_State *L, StkId func, int nresults) {
break;
}
default: { /* not a function */
- func = luaD_tryfuncTM(L, func); /* try to get '__call' metamethod */
+ luaD_tryfuncTM(L, func); /* try to get '__call' metamethod */
luaD_call(L, func, nresults); /* now it must be a function */
break;
}
diff --git a/ldo.h b/ldo.h
@@ -1,5 +1,5 @@
/*
-** $Id: ldo.h,v 2.37 2017/12/08 17:28:25 roberto Exp roberto $
+** $Id: ldo.h,v 2.38 2017/12/11 12:43:40 roberto Exp roberto $
** Stack and Call structure of Lua
** See Copyright Notice in lua.h
*/
@@ -51,7 +51,7 @@ LUAI_FUNC void luaD_hook (lua_State *L, int event, int line);
LUAI_FUNC void luaD_pretailcall (lua_State *L, CallInfo *ci, StkId func, int n);
LUAI_FUNC void luaD_call (lua_State *L, StkId func, int nResults);
LUAI_FUNC void luaD_callnoyield (lua_State *L, StkId func, int nResults);
-LUAI_FUNC StkId luaD_tryfuncTM (lua_State *L, StkId func);
+LUAI_FUNC void luaD_tryfuncTM (lua_State *L, StkId func);
LUAI_FUNC int luaD_pcall (lua_State *L, Pfunc func, void *u,
ptrdiff_t oldtop, ptrdiff_t ef);
LUAI_FUNC void luaD_poscall (lua_State *L, CallInfo *ci, StkId firstResult,
diff --git a/lvm.c b/lvm.c
@@ -1,5 +1,5 @@
/*
-** $Id: lvm.c,v 2.331 2017/12/30 20:46:18 roberto Exp roberto $
+** $Id: lvm.c,v 2.332 2018/01/09 14:23:40 roberto Exp roberto $
** Lua virtual machine
** See Copyright Notice in lua.h
*/
@@ -1501,9 +1501,7 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
b = L->top - ra;
lua_assert(GETARG_C(i) - 1 == LUA_MULTRET);
if (!ttisfunction(vra)) { /* not a function? */
- /* try to get '__call' metamethod */
- ProtectNT(ra = luaD_tryfuncTM(L, ra));
- vra = s2v(ra);
+ ProtectNT(luaD_tryfuncTM(L, ra)); /* try '__call' metamethod */
b++; /* there is now one extra argument */
}
if (!ttisLclosure(vra)) { /* C function? */