commit 11d7ba79f2a84a4feda8013a7fb270e479b785f8
parent bd5fa9cc8fdd966edc46c3de2cc420a72240ead3
Author: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Wed, 15 Jul 2009 15:37:52 -0300
tail calls do not need to move whole new frame down, only its slice
up to last parameter (the rest has not been used yet)
Diffstat:
M | lvm.c | | | 20 | ++++++++++++-------- |
1 file changed, 12 insertions(+), 8 deletions(-)
diff --git a/lvm.c b/lvm.c
@@ -1,5 +1,5 @@
/*
-** $Id: lvm.c,v 2.93 2009/06/17 17:50:09 roberto Exp roberto $
+** $Id: lvm.c,v 2.94 2009/07/01 20:31:25 roberto Exp roberto $
** Lua virtual machine
** See Copyright Notice in lua.h
*/
@@ -461,7 +461,7 @@ void luaV_execute (lua_State *L) {
/* warning!! several calls may realloc the stack and invalidate `ra' */
ra = RA(i);
lua_assert(base == ci->u.l.base);
- lua_assert(base <= L->top && L->top <= L->stack + L->stacksize);
+ lua_assert(base <= L->top && L->top < L->stack + L->stacksize);
switch (GET_OPCODE(i)) {
case OP_MOVE: {
setobjs2s(L, ra, RB(i));
@@ -658,18 +658,22 @@ void luaV_execute (lua_State *L) {
/* tail call: put called frame (n) in place of caller one (o) */
CallInfo *nci = L->ci; /* called frame */
CallInfo *oci = nci->previous; /* caller frame */
- StkId nfunc = nci->func; /* called function index */
- StkId ofunc = oci->func;
+ StkId nfunc = nci->func; /* called function */
+ StkId ofunc = oci->func; /* caller function */
+ /* last stack slot filled by 'precall' */
+ StkId lim = nci->u.l.base + getproto(nfunc)->numparams;
int aux;
+ /* close all upvalues from previous call */
if (cl->p->sizep > 0) luaF_close(L, oci->u.l.base);
- oci->u.l.base = ofunc + (nci->u.l.base - nfunc);
- for (aux = 0; nfunc+aux < L->top; aux++) /* move frame down */
+ /* move new frame into old one */
+ for (aux = 0; nfunc + aux < lim; aux++)
setobjs2s(L, ofunc + aux, nfunc + aux);
- oci->top = L->top = ofunc + aux; /* correct top */
- lua_assert(L->top == oci->u.l.base + clvalue(ofunc)->l.p->maxstacksize);
+ oci->u.l.base = ofunc + (nci->u.l.base - nfunc); /* correct base */
+ oci->top = L->top = ofunc + (L->top - nfunc); /* correct top */
oci->u.l.savedpc = nci->u.l.savedpc;
oci->u.l.tailcalls++; /* one more call lost */
ci = L->ci = oci; /* remove new frame */
+ lua_assert(L->top == oci->u.l.base + getproto(ofunc)->maxstacksize);
break; /* restart luaV_execute over new Lua function */
}
}