519 lines
14 KiB
C
519 lines
14 KiB
C
/*
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** $Id: ldo.c,v 2.38.1.4 2012/01/18 02:27:10 roberto Exp $
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** Stack and Call structure of Lua
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** See Copyright Notice in lua.h
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*/
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#include <setjmp.h>
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#include <stdlib.h>
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#include <string.h>
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#define ldo_c
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#define LUA_CORE
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#include "lua.h"
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#include "ldebug.h"
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#include "ldo.h"
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#include "lfunc.h"
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#include "lgc.h"
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#include "lmem.h"
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#include "lobject.h"
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#include "lopcodes.h"
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#include "lparser.h"
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#include "lstate.h"
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#include "lstring.h"
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#include "ltable.h"
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#include "ltm.h"
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#include "lundump.h"
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#include "lvm.h"
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#include "lzio.h"
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/*
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** {======================================================
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** Error-recovery functions
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** =======================================================
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*/
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/* chain list of long jump buffers */
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struct lua_longjmp {
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struct lua_longjmp *previous;
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luai_jmpbuf b;
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volatile int status; /* error code */
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};
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void luaD_seterrorobj (lua_State *L, int errcode, StkId oldtop) {
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switch (errcode) {
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case LUA_ERRMEM: {
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setsvalue2s(L, oldtop, luaS_newliteral(L, MEMERRMSG));
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break;
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}
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case LUA_ERRERR: {
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setsvalue2s(L, oldtop, luaS_newliteral(L, "error in error handling"));
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break;
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}
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case LUA_ERRSYNTAX:
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case LUA_ERRRUN: {
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setobjs2s(L, oldtop, L->top - 1); /* error message on current top */
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break;
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}
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}
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L->top = oldtop + 1;
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}
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static void restore_stack_limit (lua_State *L) {
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lua_assert(L->stack_last - L->stack == L->stacksize - EXTRA_STACK - 1);
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if (L->size_ci > LUAI_MAXCALLS) { /* there was an overflow? */
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int inuse = cast_int(L->ci - L->base_ci);
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if (inuse + 1 < LUAI_MAXCALLS) /* can `undo' overflow? */
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luaD_reallocCI(L, LUAI_MAXCALLS);
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}
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}
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static void resetstack (lua_State *L, int status) {
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L->ci = L->base_ci;
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L->base = L->ci->base;
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luaF_close(L, L->base); /* close eventual pending closures */
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luaD_seterrorobj(L, status, L->base);
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L->nCcalls = L->baseCcalls;
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L->allowhook = 1;
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restore_stack_limit(L);
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L->errfunc = 0;
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L->errorJmp = NULL;
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}
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void luaD_throw (lua_State *L, int errcode) {
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if (L->errorJmp) {
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L->errorJmp->status = errcode;
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LUAI_THROW(L, L->errorJmp);
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}
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else {
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L->status = cast_byte(errcode);
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if (G(L)->panic) {
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resetstack(L, errcode);
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lua_unlock(L);
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G(L)->panic(L);
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}
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exit(EXIT_FAILURE);
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}
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}
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int luaD_rawrunprotected (lua_State *L, Pfunc f, void *ud) {
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struct lua_longjmp lj;
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lj.status = 0;
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lj.previous = L->errorJmp; /* chain new error handler */
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L->errorJmp = &lj;
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LUAI_TRY(L, &lj,
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(*f)(L, ud);
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);
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L->errorJmp = lj.previous; /* restore old error handler */
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return lj.status;
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}
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/* }====================================================== */
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static void correctstack (lua_State *L, TValue *oldstack) {
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CallInfo *ci;
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GCObject *up;
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L->top = (L->top - oldstack) + L->stack;
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for (up = L->openupval; up != NULL; up = up->gch.next)
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gco2uv(up)->v = (gco2uv(up)->v - oldstack) + L->stack;
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for (ci = L->base_ci; ci <= L->ci; ci++) {
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ci->top = (ci->top - oldstack) + L->stack;
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ci->base = (ci->base - oldstack) + L->stack;
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ci->func = (ci->func - oldstack) + L->stack;
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}
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L->base = (L->base - oldstack) + L->stack;
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}
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void luaD_reallocstack (lua_State *L, int newsize) {
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TValue *oldstack = L->stack;
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int realsize = newsize + 1 + EXTRA_STACK;
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lua_assert(L->stack_last - L->stack == L->stacksize - EXTRA_STACK - 1);
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luaM_reallocvector(L, L->stack, L->stacksize, realsize, TValue);
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L->stacksize = realsize;
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L->stack_last = L->stack+newsize;
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correctstack(L, oldstack);
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}
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void luaD_reallocCI (lua_State *L, int newsize) {
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CallInfo *oldci = L->base_ci;
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luaM_reallocvector(L, L->base_ci, L->size_ci, newsize, CallInfo);
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L->size_ci = newsize;
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L->ci = (L->ci - oldci) + L->base_ci;
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L->end_ci = L->base_ci + L->size_ci - 1;
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}
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void luaD_growstack (lua_State *L, int n) {
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if (n <= L->stacksize) /* double size is enough? */
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luaD_reallocstack(L, 2*L->stacksize);
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else
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luaD_reallocstack(L, L->stacksize + n);
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}
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static CallInfo *growCI (lua_State *L) {
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if (L->size_ci > LUAI_MAXCALLS) /* overflow while handling overflow? */
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luaD_throw(L, LUA_ERRERR);
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else {
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luaD_reallocCI(L, 2*L->size_ci);
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if (L->size_ci > LUAI_MAXCALLS)
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luaG_runerror(L, "stack overflow");
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}
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return ++L->ci;
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}
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void luaD_callhook (lua_State *L, int event, int line) {
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lua_Hook hook = L->hook;
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if (hook && L->allowhook) {
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ptrdiff_t top = savestack(L, L->top);
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ptrdiff_t ci_top = savestack(L, L->ci->top);
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lua_Debug ar;
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ar.event = event;
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ar.currentline = line;
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if (event == LUA_HOOKTAILRET)
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ar.i_ci = 0; /* tail call; no debug information about it */
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else
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ar.i_ci = cast_int(L->ci - L->base_ci);
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luaD_checkstack(L, LUA_MINSTACK); /* ensure minimum stack size */
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L->ci->top = L->top + LUA_MINSTACK;
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lua_assert(L->ci->top <= L->stack_last);
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L->allowhook = 0; /* cannot call hooks inside a hook */
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lua_unlock(L);
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(*hook)(L, &ar);
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lua_lock(L);
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lua_assert(!L->allowhook);
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L->allowhook = 1;
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L->ci->top = restorestack(L, ci_top);
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L->top = restorestack(L, top);
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}
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}
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static StkId adjust_varargs (lua_State *L, Proto *p, int actual) {
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int i;
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int nfixargs = p->numparams;
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Table *htab = NULL;
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StkId base, fixed;
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for (; actual < nfixargs; ++actual)
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setnilvalue(L->top++);
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#if defined(LUA_COMPAT_VARARG)
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if (p->is_vararg & VARARG_NEEDSARG) { /* compat. with old-style vararg? */
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int nvar = actual - nfixargs; /* number of extra arguments */
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lua_assert(p->is_vararg & VARARG_HASARG);
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luaC_checkGC(L);
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luaD_checkstack(L, p->maxstacksize);
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htab = luaH_new(L, nvar, 1); /* create `arg' table */
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for (i=0; i<nvar; i++) /* put extra arguments into `arg' table */
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setobj2n(L, luaH_setnum(L, htab, i+1), L->top - nvar + i);
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/* store counter in field `n' */
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setnvalue(luaH_setstr(L, htab, luaS_newliteral(L, "n")), cast_num(nvar));
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}
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#endif
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/* move fixed parameters to final position */
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fixed = L->top - actual; /* first fixed argument */
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base = L->top; /* final position of first argument */
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for (i=0; i<nfixargs; i++) {
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setobjs2s(L, L->top++, fixed+i);
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setnilvalue(fixed+i);
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}
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/* add `arg' parameter */
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if (htab) {
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sethvalue(L, L->top++, htab);
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lua_assert(iswhite(obj2gco(htab)));
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}
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return base;
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}
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static StkId tryfuncTM (lua_State *L, StkId func) {
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const TValue *tm = luaT_gettmbyobj(L, func, TM_CALL);
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StkId p;
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ptrdiff_t funcr = savestack(L, func);
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if (!ttisfunction(tm))
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luaG_typeerror(L, func, "call");
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/* Open a hole inside the stack at `func' */
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for (p = L->top; p > func; p--) setobjs2s(L, p, p-1);
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incr_top(L);
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func = restorestack(L, funcr); /* previous call may change stack */
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setobj2s(L, func, tm); /* tag method is the new function to be called */
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return func;
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}
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#define inc_ci(L) \
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((L->ci == L->end_ci) ? growCI(L) : \
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(condhardstacktests(luaD_reallocCI(L, L->size_ci)), ++L->ci))
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int luaD_precall (lua_State *L, StkId func, int nresults) {
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LClosure *cl;
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ptrdiff_t funcr;
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if (!ttisfunction(func)) /* `func' is not a function? */
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func = tryfuncTM(L, func); /* check the `function' tag method */
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funcr = savestack(L, func);
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cl = &clvalue(func)->l;
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L->ci->savedpc = L->savedpc;
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if (!cl->isC) { /* Lua function? prepare its call */
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CallInfo *ci;
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StkId st, base;
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Proto *p = cl->p;
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luaD_checkstack(L, p->maxstacksize);
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func = restorestack(L, funcr);
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if (!p->is_vararg) { /* no varargs? */
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base = func + 1;
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if (L->top > base + p->numparams)
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L->top = base + p->numparams;
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}
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else { /* vararg function */
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int nargs = cast_int(L->top - func) - 1;
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base = adjust_varargs(L, p, nargs);
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func = restorestack(L, funcr); /* previous call may change the stack */
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}
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ci = inc_ci(L); /* now `enter' new function */
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ci->func = func;
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L->base = ci->base = base;
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ci->top = L->base + p->maxstacksize;
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lua_assert(ci->top <= L->stack_last);
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L->savedpc = p->code; /* starting point */
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ci->tailcalls = 0;
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ci->nresults = nresults;
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for (st = L->top; st < ci->top; st++)
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setnilvalue(st);
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L->top = ci->top;
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if (L->hookmask & LUA_MASKCALL) {
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L->savedpc++; /* hooks assume 'pc' is already incremented */
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luaD_callhook(L, LUA_HOOKCALL, -1);
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L->savedpc--; /* correct 'pc' */
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}
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return PCRLUA;
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}
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else { /* if is a C function, call it */
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CallInfo *ci;
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int n;
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luaD_checkstack(L, LUA_MINSTACK); /* ensure minimum stack size */
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ci = inc_ci(L); /* now `enter' new function */
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ci->func = restorestack(L, funcr);
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L->base = ci->base = ci->func + 1;
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ci->top = L->top + LUA_MINSTACK;
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lua_assert(ci->top <= L->stack_last);
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ci->nresults = nresults;
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if (L->hookmask & LUA_MASKCALL)
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luaD_callhook(L, LUA_HOOKCALL, -1);
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lua_unlock(L);
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n = (*curr_func(L)->c.f)(L); /* do the actual call */
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lua_lock(L);
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if (n < 0) /* yielding? */
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return PCRYIELD;
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else {
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luaD_poscall(L, L->top - n);
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return PCRC;
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}
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}
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}
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static StkId callrethooks (lua_State *L, StkId firstResult) {
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ptrdiff_t fr = savestack(L, firstResult); /* next call may change stack */
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luaD_callhook(L, LUA_HOOKRET, -1);
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if (f_isLua(L->ci)) { /* Lua function? */
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while ((L->hookmask & LUA_MASKRET) && L->ci->tailcalls--) /* tail calls */
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luaD_callhook(L, LUA_HOOKTAILRET, -1);
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}
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return restorestack(L, fr);
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}
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int luaD_poscall (lua_State *L, StkId firstResult) {
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StkId res;
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int wanted, i;
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CallInfo *ci;
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if (L->hookmask & LUA_MASKRET)
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firstResult = callrethooks(L, firstResult);
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ci = L->ci--;
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res = ci->func; /* res == final position of 1st result */
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wanted = ci->nresults;
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L->base = (ci - 1)->base; /* restore base */
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L->savedpc = (ci - 1)->savedpc; /* restore savedpc */
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/* move results to correct place */
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for (i = wanted; i != 0 && firstResult < L->top; i--)
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setobjs2s(L, res++, firstResult++);
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while (i-- > 0)
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setnilvalue(res++);
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L->top = res;
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return (wanted - LUA_MULTRET); /* 0 iff wanted == LUA_MULTRET */
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}
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/*
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** Call a function (C or Lua). The function to be called is at *func.
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** The arguments are on the stack, right after the function.
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** When returns, all the results are on the stack, starting at the original
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** function position.
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*/
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void luaD_call (lua_State *L, StkId func, int nResults) {
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if (++L->nCcalls >= LUAI_MAXCCALLS) {
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if (L->nCcalls == LUAI_MAXCCALLS)
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luaG_runerror(L, "C stack overflow");
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else if (L->nCcalls >= (LUAI_MAXCCALLS + (LUAI_MAXCCALLS>>3)))
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luaD_throw(L, LUA_ERRERR); /* error while handing stack error */
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}
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if (luaD_precall(L, func, nResults) == PCRLUA) /* is a Lua function? */
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luaV_execute(L, 1); /* call it */
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L->nCcalls--;
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luaC_checkGC(L);
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}
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static void resume (lua_State *L, void *ud) {
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StkId firstArg = cast(StkId, ud);
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CallInfo *ci = L->ci;
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if (L->status == 0) { /* start coroutine? */
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lua_assert(ci == L->base_ci && firstArg > L->base);
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if (luaD_precall(L, firstArg - 1, LUA_MULTRET) != PCRLUA)
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return;
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}
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else { /* resuming from previous yield */
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lua_assert(L->status == LUA_YIELD);
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L->status = 0;
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if (!f_isLua(ci)) { /* `common' yield? */
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/* finish interrupted execution of `OP_CALL' */
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lua_assert(GET_OPCODE(*((ci-1)->savedpc - 1)) == OP_CALL ||
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GET_OPCODE(*((ci-1)->savedpc - 1)) == OP_TAILCALL);
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if (luaD_poscall(L, firstArg)) /* complete it... */
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L->top = L->ci->top; /* and correct top if not multiple results */
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}
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else /* yielded inside a hook: just continue its execution */
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L->base = L->ci->base;
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}
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luaV_execute(L, cast_int(L->ci - L->base_ci));
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}
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static int resume_error (lua_State *L, const char *msg) {
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L->top = L->ci->base;
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setsvalue2s(L, L->top, luaS_new(L, msg));
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incr_top(L);
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lua_unlock(L);
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return LUA_ERRRUN;
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}
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LUA_API int lua_resume (lua_State *L, int nargs) {
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int status;
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lua_lock(L);
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if (L->status != LUA_YIELD && (L->status != 0 || L->ci != L->base_ci))
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return resume_error(L, "cannot resume non-suspended coroutine");
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if (L->nCcalls >= LUAI_MAXCCALLS)
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return resume_error(L, "C stack overflow");
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luai_userstateresume(L, nargs);
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lua_assert(L->errfunc == 0);
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L->baseCcalls = ++L->nCcalls;
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status = luaD_rawrunprotected(L, resume, L->top - nargs);
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if (status != 0) { /* error? */
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L->status = cast_byte(status); /* mark thread as `dead' */
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luaD_seterrorobj(L, status, L->top);
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L->ci->top = L->top;
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}
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else {
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lua_assert(L->nCcalls == L->baseCcalls);
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status = L->status;
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}
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--L->nCcalls;
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lua_unlock(L);
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return status;
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}
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LUA_API int lua_yield (lua_State *L, int nresults) {
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luai_userstateyield(L, nresults);
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lua_lock(L);
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if (L->nCcalls > L->baseCcalls)
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luaG_runerror(L, "attempt to yield across metamethod/C-call boundary");
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L->base = L->top - nresults; /* protect stack slots below */
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L->status = LUA_YIELD;
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lua_unlock(L);
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return -1;
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}
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int luaD_pcall (lua_State *L, Pfunc func, void *u,
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ptrdiff_t old_top, ptrdiff_t ef) {
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int status;
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unsigned short oldnCcalls = L->nCcalls;
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ptrdiff_t old_ci = saveci(L, L->ci);
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lu_byte old_allowhooks = L->allowhook;
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ptrdiff_t old_errfunc = L->errfunc;
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L->errfunc = ef;
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status = luaD_rawrunprotected(L, func, u);
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if (status != 0) { /* an error occurred? */
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StkId oldtop = restorestack(L, old_top);
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luaF_close(L, oldtop); /* close eventual pending closures */
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luaD_seterrorobj(L, status, oldtop);
|
|
L->nCcalls = oldnCcalls;
|
|
L->ci = restoreci(L, old_ci);
|
|
L->base = L->ci->base;
|
|
L->savedpc = L->ci->savedpc;
|
|
L->allowhook = old_allowhooks;
|
|
restore_stack_limit(L);
|
|
}
|
|
L->errfunc = old_errfunc;
|
|
return status;
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
** Execute a protected parser.
|
|
*/
|
|
struct SParser { /* data to `f_parser' */
|
|
ZIO *z;
|
|
Mbuffer buff; /* buffer to be used by the scanner */
|
|
const char *name;
|
|
};
|
|
|
|
static void f_parser (lua_State *L, void *ud) {
|
|
int i;
|
|
Proto *tf;
|
|
Closure *cl;
|
|
struct SParser *p = cast(struct SParser *, ud);
|
|
int c = luaZ_lookahead(p->z);
|
|
luaC_checkGC(L);
|
|
tf = ((c == LUA_SIGNATURE[0]) ? luaU_undump : luaY_parser)(L, p->z,
|
|
&p->buff, p->name);
|
|
cl = luaF_newLclosure(L, tf->nups, hvalue(gt(L)));
|
|
cl->l.p = tf;
|
|
for (i = 0; i < tf->nups; i++) /* initialize eventual upvalues */
|
|
cl->l.upvals[i] = luaF_newupval(L);
|
|
setclvalue(L, L->top, cl);
|
|
incr_top(L);
|
|
}
|
|
|
|
|
|
int luaD_protectedparser (lua_State *L, ZIO *z, const char *name) {
|
|
struct SParser p;
|
|
int status;
|
|
p.z = z; p.name = name;
|
|
luaZ_initbuffer(L, &p.buff);
|
|
status = luaD_pcall(L, f_parser, &p, savestack(L, L->top), L->errfunc);
|
|
luaZ_freebuffer(L, &p.buff);
|
|
return status;
|
|
}
|
|
|
|
|