commit 9a5d6aedb773a61153b07a0939d651efe8ee1753
parent 89e3a843442679252773a29114c8552e3f59777d
Author: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Fri, 13 Nov 2015 11:24:00 -0200
trying to optimize a little 'luaD_poscall'
Diffstat:
| M | ldo.c | | | 72 | +++++++++++++++++++++++++++++++++++++++++++++++++++--------------------- |
| M | ldo.h | | | 5 | +++-- |
| M | lvm.c | | | 4 | ++-- |
3 files changed, 56 insertions(+), 25 deletions(-)
diff --git a/ldo.c b/ldo.c
@@ -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 */
@@ -398,14 +398,56 @@ 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 */
}
diff --git a/ldo.h b/ldo.h
@@ -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);
diff --git a/lvm.c b/lvm.c
@@ -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 */
