diff --git a/ldo.c b/ldo.c index e4f09076..aabc803c 100644 --- 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 */ @@ -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 */ } diff --git a/ldo.h b/ldo.h index de6988fd..bed54624 100644 --- 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 index ecf00c39..43485804 100644 --- 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 */