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trying to optimize a little 'luaD_poscall'

This commit is contained in:
Roberto Ierusalimschy 2015-11-13 11:24:26 -02:00
parent 89e3a84344
commit 9a5d6aedb7
3 changed files with 56 additions and 25 deletions
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72
ldo.c
View File

@ -1,5 +1,5 @@
/*
** $Id: ldo.c,v 2.147 2015/11/02 16:09:30 roberto Exp roberto $
** $Id: ldo.c,v 2.148 2015/11/02 18:48:49 roberto Exp roberto $
** Stack and Call structure of Lua
** See Copyright Notice in lua.h
*/
@ -360,7 +360,7 @@ int luaD_precall (lua_State *L, StkId func, int nresults) {
n = (*f)(L); /* do the actual call */
lua_lock(L);
api_checknelems(L, n);
luaD_poscall(L, L->top - n, n);
luaD_poscall(L, ci, L->top - n, n);
return 1;
}
case LUA_TLCL: { /* Lua function: prepare its call */
@ -397,15 +397,57 @@ int luaD_precall (lua_State *L, StkId func, int nresults) {
}
/*
** Given 'nres' results at 'firstResult', move 'wanted' of them to 'res'.
** Handle most typical cases (zero results for commands, one result for
** expressions, multiple results for tail calls/single parameters)
** separated.
*/
static int moveresults (lua_State *L, const TValue *firstResult, StkId res,
int nres, int wanted) {
switch (wanted) { /* handle typical cases separately */
case 0: break; /* nothing to move */
case 1: { /* one result needed */
if (nres == 0) /* no results? */
firstResult = luaO_nilobject; /* ajdust with nil */
setobjs2s(L, res, firstResult); /* move it to proper place */
break;
}
case LUA_MULTRET: {
int i;
for (i = 0; i < nres; i++) /* move all results to correct place */
setobjs2s(L, res + i, firstResult + i);
L->top = res + nres;
return 0; /* wanted == LUA_MULTRET */
}
default: {
int i;
if (wanted <= nres) { /* enough results? */
for (i = 0; i < wanted; i++) /* move wanted results to correct place */
setobjs2s(L, res + i, firstResult + i);
}
else { /* not enough results; use all of them plus nils */
for (i = 0; i < nres; i++) /* move all results to correct place */
setobjs2s(L, res + i, firstResult + i);
for (; i < wanted; i++) /* complete wanted number of results */
setnilvalue(res + i);
}
break;
}
}
L->top = res + wanted; /* top points after the last result */
return 1;
}
/*
** Finishes a function call: calls hook if necessary, removes CallInfo,
** moves corrent number of results to proper place; returns 0 iff call
** wanted multiple (variable number of) results.
*/
int luaD_poscall (lua_State *L, StkId firstResult, int nres) {
int luaD_poscall (lua_State *L, CallInfo *ci, StkId firstResult, int nres) {
StkId res;
int wanted, i;
CallInfo *ci = L->ci;
int wanted = ci->nresults;
if (L->hookmask & (LUA_MASKRET | LUA_MASKLINE)) {
if (L->hookmask & LUA_MASKRET) {
ptrdiff_t fr = savestack(L, firstResult); /* hook may change stack */
@ -415,21 +457,9 @@ int luaD_poscall (lua_State *L, StkId firstResult, int nres) {
L->oldpc = ci->previous->u.l.savedpc; /* 'oldpc' for caller function */
}
res = ci->func; /* res == final position of 1st result */
wanted = ci->nresults;
L->ci = ci->previous; /* back to caller */
/* comparison is 'unsigned' to make 'LUA_MULTRET' fails test */
if ((unsigned int)wanted <= (unsigned int)nres) { /* enough results? */
for (i = 0; i < wanted; i++) /* move wanted results to correct place */
setobjs2s(L, res + i, firstResult + i);
}
else { /* not enough results (or multret); use all of them plus nils */
for (i = 0; i < nres; i++) /* move all results to correct place */
setobjs2s(L, res + i, firstResult + i);
for (; i < wanted; i++) /* complete wanted number of results */
setnilvalue(res + i);
}
L->top = res + i; /* top points after the last result */
return (wanted - LUA_MULTRET); /* 0 iff wanted == LUA_MULTRET */
/* move results to proper place */
return moveresults(L, firstResult, res, nres, wanted);
}
@ -497,7 +527,7 @@ static void finishCcall (lua_State *L, int status) {
lua_lock(L);
api_checknelems(L, n);
/* finish 'luaD_precall' */
luaD_poscall(L, L->top - n, n);
luaD_poscall(L, ci, L->top - n, n);
}
@ -608,7 +638,7 @@ static void resume (lua_State *L, void *ud) {
api_checknelems(L, n);
firstArg = L->top - n; /* yield results come from continuation */
}
luaD_poscall(L, firstArg, n); /* finish 'luaD_precall' */
luaD_poscall(L, ci, firstArg, n); /* finish 'luaD_precall' */
}
unroll(L, NULL); /* run continuation */
}

5
ldo.h
View File

@ -1,5 +1,5 @@
/*
** $Id: ldo.h,v 2.24 2015/11/02 16:09:30 roberto Exp roberto $
** $Id: ldo.h,v 2.25 2015/11/02 18:48:07 roberto Exp roberto $
** Stack and Call structure of Lua
** See Copyright Notice in lua.h
*/
@ -44,7 +44,8 @@ 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 int luaD_pcall (lua_State *L, Pfunc func, void *u,
ptrdiff_t oldtop, ptrdiff_t ef);
LUAI_FUNC int luaD_poscall (lua_State *L, StkId firstResult, int nres);
LUAI_FUNC int luaD_poscall (lua_State *L, CallInfo *ci, StkId firstResult,
int nres);
LUAI_FUNC void luaD_reallocstack (lua_State *L, int newsize);
LUAI_FUNC void luaD_growstack (lua_State *L, int n);
LUAI_FUNC void luaD_shrinkstack (lua_State *L);

4
lvm.c
View File

@ -1,5 +1,5 @@
/*
** $Id: lvm.c,v 2.260 2015/11/02 18:48:07 roberto Exp roberto $
** $Id: lvm.c,v 2.261 2015/11/12 18:08:58 roberto Exp roberto $
** Lua virtual machine
** See Copyright Notice in lua.h
*/
@ -1157,7 +1157,7 @@ void luaV_execute (lua_State *L) {
vmcase(OP_RETURN) {
int b = GETARG_B(i);
if (cl->p->sizep > 0) luaF_close(L, base);
b = luaD_poscall(L, ra, (b != 0 ? b - 1 : cast_int(L->top - ra)));
b = luaD_poscall(L, ci, ra, (b != 0 ? b - 1 : cast_int(L->top - ra)));
if (ci->callstatus & CIST_FRESH) /* local 'ci' still from callee */
return; /* external invocation: return */
else { /* invocation via reentry: continue execution */