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tail calls do not need to move whole new frame down, only its slice

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up to last parameter (the rest has not been used yet)
This commit is contained in:
Roberto Ierusalimschy 2009-07-15 15:38:16 -03:00
parent bd5fa9cc8f
commit 11d7ba79f2
1 changed files with 12 additions and 8 deletions
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20
lvm.c
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@ -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 */
}
}