diff options
Diffstat (limited to 'src/ldo.c')
| -rw-r--r-- | src/ldo.c | 287 |
1 files changed, 186 insertions, 101 deletions
diff --git a/src/ldo.c b/src/ldo.c index 6159e51da2d4..90b695fb04c7 100644 --- a/src/ldo.c +++ b/src/ldo.c @@ -1,5 +1,5 @@ /* -** $Id: ldo.c,v 2.135 2014/11/11 17:13:39 roberto Exp $ +** $Id: ldo.c,v 2.157 2016/12/13 15:52:21 roberto Exp $ ** Stack and Call structure of Lua ** See Copyright Notice in lua.h */ @@ -150,6 +150,11 @@ int luaD_rawrunprotected (lua_State *L, Pfunc f, void *ud) { /* }====================================================== */ +/* +** {================================================================== +** Stack reallocation +** =================================================================== +*/ static void correctstack (lua_State *L, TValue *oldstack) { CallInfo *ci; UpVal *up; @@ -206,9 +211,9 @@ static int stackinuse (lua_State *L) { CallInfo *ci; StkId lim = L->top; for (ci = L->ci; ci != NULL; ci = ci->previous) { - lua_assert(ci->top <= L->stack_last); if (lim < ci->top) lim = ci->top; } + lua_assert(lim <= L->stack_last); return cast_int(lim - L->stack) + 1; /* part of stack in use */ } @@ -216,22 +221,38 @@ static int stackinuse (lua_State *L) { void luaD_shrinkstack (lua_State *L) { int inuse = stackinuse(L); int goodsize = inuse + (inuse / 8) + 2*EXTRA_STACK; - if (goodsize > LUAI_MAXSTACK) goodsize = LUAI_MAXSTACK; - if (L->stacksize > LUAI_MAXSTACK) /* was handling stack overflow? */ + if (goodsize > LUAI_MAXSTACK) + goodsize = LUAI_MAXSTACK; /* respect stack limit */ + if (L->stacksize > LUAI_MAXSTACK) /* had been handling stack overflow? */ luaE_freeCI(L); /* free all CIs (list grew because of an error) */ else luaE_shrinkCI(L); /* shrink list */ - if (inuse > LUAI_MAXSTACK || /* still handling stack overflow? */ - goodsize >= L->stacksize) /* would grow instead of shrink? */ - condmovestack(L); /* don't change stack (change only for debugging) */ - else - luaD_reallocstack(L, goodsize); /* shrink it */ + /* if thread is currently not handling a stack overflow and its + good size is smaller than current size, shrink its stack */ + if (inuse <= (LUAI_MAXSTACK - EXTRA_STACK) && + goodsize < L->stacksize) + luaD_reallocstack(L, goodsize); + else /* don't change stack */ + condmovestack(L,{},{}); /* (change only for debugging) */ +} + + +void luaD_inctop (lua_State *L) { + luaD_checkstack(L, 1); + L->top++; } +/* }================================================================== */ + +/* +** Call a hook for the given event. Make sure there is a hook to be +** called. (Both 'L->hook' and 'L->hookmask', which triggers this +** function, can be changed asynchronously by signals.) +*/ void luaD_hook (lua_State *L, int event, int line) { lua_Hook hook = L->hook; - if (hook && L->allowhook) { + if (hook && L->allowhook) { /* make sure there is a hook */ CallInfo *ci = L->ci; ptrdiff_t top = savestack(L, L->top); ptrdiff_t ci_top = savestack(L, ci->top); @@ -273,15 +294,15 @@ static StkId adjust_varargs (lua_State *L, Proto *p, int actual) { int i; int nfixargs = p->numparams; StkId base, fixed; - lua_assert(actual >= nfixargs); /* move fixed parameters to final position */ - luaD_checkstack(L, p->maxstacksize); /* check again for new 'base' */ fixed = L->top - actual; /* first fixed argument */ base = L->top; /* final position of first argument */ - for (i=0; i<nfixargs; i++) { + for (i = 0; i < nfixargs && i < actual; i++) { setobjs2s(L, L->top++, fixed + i); - setnilvalue(fixed + i); + setnilvalue(fixed + i); /* erase original copy (for GC) */ } + for (; i < nfixargs; i++) + setnilvalue(L->top++); /* complete missing arguments */ return base; } @@ -304,74 +325,145 @@ static void tryfuncTM (lua_State *L, StkId func) { } +/* +** 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; /* adjust 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 current number of results to proper place; returns 0 iff call +** wanted multiple (variable number of) results. +*/ +int luaD_poscall (lua_State *L, CallInfo *ci, StkId firstResult, int nres) { + StkId res; + 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 */ + luaD_hook(L, LUA_HOOKRET, -1); + firstResult = restorestack(L, fr); + } + L->oldpc = ci->previous->u.l.savedpc; /* 'oldpc' for caller function */ + } + res = ci->func; /* res == final position of 1st result */ + L->ci = ci->previous; /* back to caller */ + /* move results to proper place */ + return moveresults(L, firstResult, res, nres, wanted); +} + + #define next_ci(L) (L->ci = (L->ci->next ? L->ci->next : luaE_extendCI(L))) +/* macro to check stack size, preserving 'p' */ +#define checkstackp(L,n,p) \ + luaD_checkstackaux(L, n, \ + ptrdiff_t t__ = savestack(L, p); /* save 'p' */ \ + luaC_checkGC(L), /* stack grow uses memory */ \ + p = restorestack(L, t__)) /* 'pos' part: restore 'p' */ + + /* -** returns true if function has been executed (C function) +** Prepares a function call: checks the stack, creates a new CallInfo +** entry, fills in the relevant information, calls hook if needed. +** If function is a C function, does the call, too. (Otherwise, leave +** the execution ('luaV_execute') to the caller, to allow stackless +** calls.) Returns true iff function has been executed (C function). */ int luaD_precall (lua_State *L, StkId func, int nresults) { lua_CFunction f; CallInfo *ci; - int n; /* number of arguments (Lua) or returns (C) */ - ptrdiff_t funcr = savestack(L, func); switch (ttype(func)) { + case LUA_TCCL: /* C closure */ + f = clCvalue(func)->f; + goto Cfunc; case LUA_TLCF: /* light C function */ f = fvalue(func); - goto Cfunc; - case LUA_TCCL: { /* C closure */ - f = clCvalue(func)->f; - Cfunc: - luaD_checkstack(L, LUA_MINSTACK); /* ensure minimum stack size */ + Cfunc: { + int n; /* number of returns */ + checkstackp(L, LUA_MINSTACK, func); /* ensure minimum stack size */ ci = next_ci(L); /* now 'enter' new function */ ci->nresults = nresults; - ci->func = restorestack(L, funcr); + ci->func = func; ci->top = L->top + LUA_MINSTACK; lua_assert(ci->top <= L->stack_last); ci->callstatus = 0; - luaC_checkGC(L); /* stack grow uses memory */ if (L->hookmask & LUA_MASKCALL) luaD_hook(L, LUA_HOOKCALL, -1); lua_unlock(L); n = (*f)(L); /* do the actual call */ lua_lock(L); api_checknelems(L, n); - luaD_poscall(L, L->top - n); + luaD_poscall(L, ci, L->top - n, n); return 1; } case LUA_TLCL: { /* Lua function: prepare its call */ StkId base; Proto *p = clLvalue(func)->p; - n = cast_int(L->top - func) - 1; /* number of real arguments */ - luaD_checkstack(L, p->maxstacksize); - for (; n < p->numparams; n++) - setnilvalue(L->top++); /* complete missing arguments */ - if (!p->is_vararg) { - func = restorestack(L, funcr); - base = func + 1; - } - else { + int n = cast_int(L->top - func) - 1; /* number of real arguments */ + int fsize = p->maxstacksize; /* frame size */ + checkstackp(L, fsize, func); + if (p->is_vararg) base = adjust_varargs(L, p, n); - func = restorestack(L, funcr); /* previous call can change stack */ + else { /* non vararg function */ + for (; n < p->numparams; n++) + setnilvalue(L->top++); /* complete missing arguments */ + base = func + 1; } ci = next_ci(L); /* now 'enter' new function */ ci->nresults = nresults; ci->func = func; ci->u.l.base = base; - ci->top = base + p->maxstacksize; + L->top = ci->top = base + fsize; lua_assert(ci->top <= L->stack_last); ci->u.l.savedpc = p->code; /* starting point */ ci->callstatus = CIST_LUA; - L->top = ci->top; - luaC_checkGC(L); /* stack grow uses memory */ if (L->hookmask & LUA_MASKCALL) callhook(L, ci); return 0; } default: { /* not a function */ - luaD_checkstack(L, 1); /* ensure space for metamethod */ - func = restorestack(L, funcr); /* previous call may change stack */ + checkstackp(L, 1, func); /* ensure space for metamethod */ tryfuncTM(L, func); /* try to get '__call' metamethod */ return luaD_precall(L, func, nresults); /* now it must be a function */ } @@ -379,28 +471,18 @@ int luaD_precall (lua_State *L, StkId func, int nresults) { } -int luaD_poscall (lua_State *L, StkId firstResult) { - StkId res; - int wanted, i; - CallInfo *ci = L->ci; - if (L->hookmask & (LUA_MASKRET | LUA_MASKLINE)) { - if (L->hookmask & LUA_MASKRET) { - ptrdiff_t fr = savestack(L, firstResult); /* hook may change stack */ - luaD_hook(L, LUA_HOOKRET, -1); - firstResult = restorestack(L, fr); - } - 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 = ci->previous; /* back to caller */ - /* move results to correct place */ - for (i = wanted; i != 0 && firstResult < L->top; i--) - setobjs2s(L, res++, firstResult++); - while (i-- > 0) - setnilvalue(res++); - L->top = res; - return (wanted - LUA_MULTRET); /* 0 iff wanted == LUA_MULTRET */ +/* +** Check appropriate error for stack overflow ("regular" overflow or +** overflow while handling stack overflow). If 'nCalls' is larger than +** LUAI_MAXCCALLS (which means it is handling a "regular" overflow) but +** smaller than 9/8 of LUAI_MAXCCALLS, does not report an error (to +** allow overflow handling to work) +*/ +static void stackerror (lua_State *L) { + if (L->nCcalls == LUAI_MAXCCALLS) + luaG_runerror(L, "C stack overflow"); + else if (L->nCcalls >= (LUAI_MAXCCALLS + (LUAI_MAXCCALLS>>3))) + luaD_throw(L, LUA_ERRERR); /* error while handing stack error */ } @@ -410,22 +492,26 @@ int luaD_poscall (lua_State *L, StkId firstResult) { ** When returns, all the results are on the stack, starting at the original ** function position. */ -void luaD_call (lua_State *L, StkId func, int nResults, int allowyield) { - if (++L->nCcalls >= LUAI_MAXCCALLS) { - if (L->nCcalls == LUAI_MAXCCALLS) - luaG_runerror(L, "C stack overflow"); - else if (L->nCcalls >= (LUAI_MAXCCALLS + (LUAI_MAXCCALLS>>3))) - luaD_throw(L, LUA_ERRERR); /* error while handing stack error */ - } - if (!allowyield) L->nny++; +void luaD_call (lua_State *L, StkId func, int nResults) { + if (++L->nCcalls >= LUAI_MAXCCALLS) + stackerror(L); if (!luaD_precall(L, func, nResults)) /* is a Lua function? */ luaV_execute(L); /* call it */ - if (!allowyield) L->nny--; L->nCcalls--; } /* +** Similar to 'luaD_call', but does not allow yields during the call +*/ +void luaD_callnoyield (lua_State *L, StkId func, int nResults) { + L->nny++; + luaD_call(L, func, nResults); + L->nny--; +} + + +/* ** Completes the execution of an interrupted C function, calling its ** continuation function. */ @@ -437,19 +523,17 @@ static void finishCcall (lua_State *L, int status) { /* error status can only happen in a protected call */ lua_assert((ci->callstatus & CIST_YPCALL) || status == LUA_YIELD); if (ci->callstatus & CIST_YPCALL) { /* was inside a pcall? */ - ci->callstatus &= ~CIST_YPCALL; /* finish 'lua_pcall' */ - L->errfunc = ci->u.c.old_errfunc; + ci->callstatus &= ~CIST_YPCALL; /* continuation is also inside it */ + L->errfunc = ci->u.c.old_errfunc; /* with the same error function */ } /* finish 'lua_callk'/'lua_pcall'; CIST_YPCALL and 'errfunc' already handled */ adjustresults(L, ci->nresults); - /* call continuation function */ lua_unlock(L); - n = (*ci->u.c.k)(L, status, ci->u.c.ctx); + n = (*ci->u.c.k)(L, status, ci->u.c.ctx); /* call continuation function */ lua_lock(L); api_checknelems(L, n); - /* finish 'luaD_precall' */ - luaD_poscall(L, L->top - n); + luaD_poscall(L, ci, L->top - n, n); /* finish 'luaD_precall' */ } @@ -512,15 +596,16 @@ static int recover (lua_State *L, int status) { /* -** signal an error in the call to 'resume', not in the execution of the -** coroutine itself. (Such errors should not be handled by any coroutine -** error handler and should not kill the coroutine.) +** Signal an error in the call to 'lua_resume', not in the execution +** of the coroutine itself. (Such errors should not be handled by any +** coroutine error handler and should not kill the coroutine.) */ -static l_noret resume_error (lua_State *L, const char *msg, StkId firstArg) { - L->top = firstArg; /* remove args from the stack */ +static int resume_error (lua_State *L, const char *msg, int narg) { + L->top -= narg; /* remove args from the stack */ setsvalue2s(L, L->top, luaS_new(L, msg)); /* push error message */ api_incr_top(L); - luaD_throw(L, -1); /* jump back to 'lua_resume' */ + lua_unlock(L); + return LUA_ERRRUN; } @@ -532,51 +617,51 @@ static l_noret resume_error (lua_State *L, const char *msg, StkId firstArg) { ** coroutine. */ static void resume (lua_State *L, void *ud) { - int nCcalls = L->nCcalls; - StkId firstArg = cast(StkId, ud); + int n = *(cast(int*, ud)); /* number of arguments */ + StkId firstArg = L->top - n; /* first argument */ CallInfo *ci = L->ci; - if (nCcalls >= LUAI_MAXCCALLS) - resume_error(L, "C stack overflow", firstArg); - if (L->status == LUA_OK) { /* may be starting a coroutine */ - if (ci != &L->base_ci) /* not in base level? */ - resume_error(L, "cannot resume non-suspended coroutine", firstArg); - /* coroutine is in base level; start running it */ + if (L->status == LUA_OK) { /* starting a coroutine? */ if (!luaD_precall(L, firstArg - 1, LUA_MULTRET)) /* Lua function? */ luaV_execute(L); /* call it */ } - else if (L->status != LUA_YIELD) - resume_error(L, "cannot resume dead coroutine", firstArg); else { /* resuming from previous yield */ + lua_assert(L->status == LUA_YIELD); L->status = LUA_OK; /* mark that it is running (again) */ ci->func = restorestack(L, ci->extra); if (isLua(ci)) /* yielded inside a hook? */ luaV_execute(L); /* just continue running Lua code */ else { /* 'common' yield */ if (ci->u.c.k != NULL) { /* does it have a continuation function? */ - int n; lua_unlock(L); n = (*ci->u.c.k)(L, LUA_YIELD, ci->u.c.ctx); /* call continuation */ lua_lock(L); api_checknelems(L, n); firstArg = L->top - n; /* yield results come from continuation */ } - luaD_poscall(L, firstArg); /* finish 'luaD_precall' */ + luaD_poscall(L, ci, firstArg, n); /* finish 'luaD_precall' */ } unroll(L, NULL); /* run continuation */ } - lua_assert(nCcalls == L->nCcalls); } LUA_API int lua_resume (lua_State *L, lua_State *from, int nargs) { int status; - int oldnny = L->nny; /* save "number of non-yieldable" calls */ + unsigned short oldnny = L->nny; /* save "number of non-yieldable" calls */ lua_lock(L); - luai_userstateresume(L, nargs); + if (L->status == LUA_OK) { /* may be starting a coroutine */ + if (L->ci != &L->base_ci) /* not in base level? */ + return resume_error(L, "cannot resume non-suspended coroutine", nargs); + } + else if (L->status != LUA_YIELD) + return resume_error(L, "cannot resume dead coroutine", nargs); L->nCcalls = (from) ? from->nCcalls + 1 : 1; + if (L->nCcalls >= LUAI_MAXCCALLS) + return resume_error(L, "C stack overflow", nargs); + luai_userstateresume(L, nargs); L->nny = 0; /* allow yields */ api_checknelems(L, (L->status == LUA_OK) ? nargs + 1 : nargs); - status = luaD_rawrunprotected(L, resume, L->top - nargs); + status = luaD_rawrunprotected(L, resume, &nargs); if (status == -1) /* error calling 'lua_resume'? */ status = LUA_ERRRUN; else { /* continue running after recoverable errors */ @@ -619,7 +704,7 @@ LUA_API int lua_yieldk (lua_State *L, int nresults, lua_KContext ctx, L->status = LUA_YIELD; ci->extra = savestack(L, ci->func); /* save current 'func' */ if (isLua(ci)) { /* inside a hook? */ - api_check(k == NULL, "hooks cannot continue after yielding"); + api_check(L, k == NULL, "hooks cannot continue after yielding"); } else { if ((ci->u.c.k = k) != NULL) /* is there a continuation? */ @@ -684,7 +769,7 @@ static void f_parser (lua_State *L, void *ud) { int c = zgetc(p->z); /* read first character */ if (c == LUA_SIGNATURE[0]) { checkmode(L, p->mode, "binary"); - cl = luaU_undump(L, p->z, &p->buff, p->name); + cl = luaU_undump(L, p->z, p->name); } else { checkmode(L, p->mode, "text"); |