lvm.c

世界上最快的脚本语言lua的源码

#define dojump(pc, i)	((pc) += (i))


StkId luaV_execute (lua_State *L) {
  LClosure *cl;
  TObject *k;
  const Instruction *pc;
 callentry:  /* entry point when calling new functions */
  if (L->hookmask & LUA_MASKCALL) {
    L->ci->u.l.pc = &pc;
    luaD_callhook(L, LUA_HOOKCALL, -1);
  }
 retentry:  /* entry point when returning to old functions */
  L->ci->u.l.pc = &pc;
  lua_assert(L->ci->state == CI_SAVEDPC ||
             L->ci->state == (CI_SAVEDPC | CI_CALLING));
  L->ci->state = CI_HASFRAME;  /* activate frame */
  pc = L->ci->u.l.savedpc;
  cl = &clvalue(L->base - 1)->l;
  k = cl->p->k;
  /* main loop of interpreter */
  for (;;) {
    const Instruction i = *pc++;
    StkId base, ra;
    if ((L->hookmask & (LUA_MASKLINE | LUA_MASKCOUNT)) &&
        (--L->hookcount == 0 || L->hookmask & LUA_MASKLINE)) {
      traceexec(L);
      if (L->ci->state & CI_YIELD) {  /* did hook yield? */
        L->ci->u.l.savedpc = pc - 1;
        L->ci->state = CI_YIELD | CI_SAVEDPC;
        return NULL;
      }
    }
    /* warning!! several calls may realloc the stack and invalidate `ra' */
    base = L->base;
    ra = RA(i);
    lua_assert(L->ci->state & CI_HASFRAME);
    lua_assert(base == L->ci->base);
    lua_assert(L->top <= L->stack + L->stacksize && L->top >= base);
    lua_assert(L->top == L->ci->top ||
         GET_OPCODE(i) == OP_CALL ||   GET_OPCODE(i) == OP_TAILCALL ||
         GET_OPCODE(i) == OP_RETURN || GET_OPCODE(i) == OP_SETLISTO);
    switch (GET_OPCODE(i)) {
      case OP_MOVE: {
        setobjs2s(ra, RB(i));
        break;
      }
      case OP_LOADK: {
        setobj2s(ra, KBx(i));
        break;
      }
      case OP_LOADBOOL: {
        setbvalue(ra, GETARG_B(i));
        if (GETARG_C(i)) pc++;  /* skip next instruction (if C) */
        break;
      }
      case OP_LOADNIL: {
        TObject *rb = RB(i);
        do {
          setnilvalue(rb--);
        } while (rb >= ra);
        break;
      }
      case OP_GETUPVAL: {
        int b = GETARG_B(i);
        setobj2s(ra, cl->upvals[b]->v);
        break;
      }
      case OP_GETGLOBAL: {
        TObject *rb = KBx(i);
        const TObject *v;
        lua_assert(ttisstring(rb) && ttistable(&cl->g));
        v = luaH_getstr(hvalue(&cl->g), tsvalue(rb));
        if (!ttisnil(v)) { setobj2s(ra, v); }
        else
          setobj2s(XRA(i), luaV_index(L, &cl->g, rb, 0));
        break;
      }
      case OP_GETTABLE: {
        StkId rb = RB(i);
        TObject *rc = RKC(i);
        if (ttistable(rb)) {
          const TObject *v = luaH_get(hvalue(rb), rc);
          if (!ttisnil(v)) { setobj2s(ra, v); }
          else
            setobj2s(XRA(i), luaV_index(L, rb, rc, 0));
        }
        else
          setobj2s(XRA(i), luaV_getnotable(L, rb, rc, 0));
        break;
      }
      case OP_SETGLOBAL: {
        lua_assert(ttisstring(KBx(i)) && ttistable(&cl->g));
        luaV_settable(L, &cl->g, KBx(i), ra);
        break;
      }
      case OP_SETUPVAL: {
        int b = GETARG_B(i);
        setobj(cl->upvals[b]->v, ra);  /* write barrier */
        break;
      }
      case OP_SETTABLE: {
        luaV_settable(L, ra, RKB(i), RKC(i));
        break;
      }
      case OP_NEWTABLE: {
        int b = GETARG_B(i);
        b = fb2int(b);
        sethvalue(ra, luaH_new(L, b, GETARG_C(i)));
        luaC_checkGC(L);
        break;
      }
      case OP_SELF: {
        StkId rb = RB(i);
        TObject *rc = RKC(i);
        runtime_check(L, ttisstring(rc));
        setobjs2s(ra+1, rb);
        if (ttistable(rb)) {
          const TObject *v = luaH_getstr(hvalue(rb), tsvalue(rc));
          if (!ttisnil(v)) { setobj2s(ra, v); }
          else
            setobj2s(XRA(i), luaV_index(L, rb, rc, 0));
        }
        else
          setobj2s(XRA(i), luaV_getnotable(L, rb, rc, 0));
        break;
      }
      case OP_ADD: {
        TObject *rb = RKB(i);
        TObject *rc = RKC(i);
        if (ttisnumber(rb) && ttisnumber(rc)) {
          setnvalue(ra, nvalue(rb) + nvalue(rc));
        }
        else
          Arith(L, ra, rb, rc, TM_ADD);
        break;
      }
      case OP_SUB: {
        TObject *rb = RKB(i);
        TObject *rc = RKC(i);
        if (ttisnumber(rb) && ttisnumber(rc)) {
          setnvalue(ra, nvalue(rb) - nvalue(rc));
        }
        else
          Arith(L, ra, rb, rc, TM_SUB);
        break;
      }
      case OP_MUL: {
        TObject *rb = RKB(i);
        TObject *rc = RKC(i);
        if (ttisnumber(rb) && ttisnumber(rc)) {
          setnvalue(ra, nvalue(rb) * nvalue(rc));
        }
        else
          Arith(L, ra, rb, rc, TM_MUL);
        break;
      }
      case OP_DIV: {
        TObject *rb = RKB(i);
        TObject *rc = RKC(i);
        if (ttisnumber(rb) && ttisnumber(rc)) {
          setnvalue(ra, nvalue(rb) / nvalue(rc));
        }
        else
          Arith(L, ra, rb, rc, TM_DIV);
        break;
      }
      case OP_POW: {
        Arith(L, ra, RKB(i), RKC(i), TM_POW);
        break;
      }
      case OP_UNM: {
        const TObject *rb = RB(i);
        TObject temp;
        if (tonumber(rb, &temp)) {
          setnvalue(ra, -nvalue(rb));
        }
        else {
          setnilvalue(&temp);
          if (!call_binTM(L, RB(i), &temp, ra, TM_UNM))
            luaG_aritherror(L, RB(i), &temp);
        }
        break;
      }
      case OP_NOT: {
        int res = l_isfalse(RB(i));  /* next assignment may change this value */
        setbvalue(ra, res);
        break;
      }
      case OP_CONCAT: {
        int b = GETARG_B(i);
        int c = GETARG_C(i);
        luaV_concat(L, c-b+1, c);  /* may change `base' (and `ra') */
        base = L->base;
        setobjs2s(RA(i), base+b);
        luaC_checkGC(L);
        break;
      }
      case OP_JMP: {
        dojump(pc, GETARG_sBx(i));
        break;
      }
      case OP_EQ: {
        if (equalobj(L, RKB(i), RKC(i)) != GETARG_A(i)) pc++;
        else dojump(pc, GETARG_sBx(*pc) + 1);
        break;
      }
      case OP_LT: {
        if (luaV_lessthan(L, RKB(i), RKC(i)) != GETARG_A(i)) pc++;
        else dojump(pc, GETARG_sBx(*pc) + 1);
        break;
      }
      case OP_LE: {
        if (luaV_lessequal(L, RKB(i), RKC(i)) != GETARG_A(i)) pc++;
        else dojump(pc, GETARG_sBx(*pc) + 1);
        break;
      }
      case OP_TEST: {
        TObject *rb = RB(i);
        if (l_isfalse(rb) == GETARG_C(i)) pc++;
        else {
          setobjs2s(ra, rb);
          dojump(pc, GETARG_sBx(*pc) + 1);
        }
        break;
      }
      case OP_CALL:
      case OP_TAILCALL: {
        StkId firstResult;
        int b = GETARG_B(i);
        int nresults;
        if (b != 0) L->top = ra+b;  /* else previous instruction set top */
        nresults = GETARG_C(i) - 1;
        firstResult = luaD_precall(L, ra);
        if (firstResult) {
          if (firstResult > L->top) {  /* yield? */
            lua_assert(L->ci->state == (CI_C | CI_YIELD));
            (L->ci - 1)->u.l.savedpc = pc;
            (L->ci - 1)->state = CI_SAVEDPC;
            return NULL;
          }
          /* it was a C function (`precall' called it); adjust results */
          luaD_poscall(L, nresults, firstResult);
          if (nresults >= 0) L->top = L->ci->top;
        }
        else {  /* it is a Lua function */
          if (GET_OPCODE(i) == OP_CALL) {  /* regular call? */
            (L->ci-1)->u.l.savedpc = pc;  /* save `pc' to return later */
            (L->ci-1)->state = (CI_SAVEDPC | CI_CALLING);
          }
          else {  /* tail call: put new frame in place of previous one */
            int aux;
            base = (L->ci - 1)->base;  /* `luaD_precall' may change the stack */
            ra = RA(i);
            if (L->openupval) luaF_close(L, base);
            for (aux = 0; ra+aux < L->top; aux++)  /* move frame down */
              setobjs2s(base+aux-1, ra+aux);
            (L->ci - 1)->top = L->top = base+aux;  /* correct top */
            lua_assert(L->ci->state & CI_SAVEDPC);
            (L->ci - 1)->u.l.savedpc = L->ci->u.l.savedpc;
            (L->ci - 1)->u.l.tailcalls++;  /* one more call lost */
            (L->ci - 1)->state = CI_SAVEDPC;
            L->ci--;  /* remove new frame */
            L->base = L->ci->base;
          }
          goto callentry;
        }
        break;
      }
      case OP_RETURN: {
        CallInfo *ci = L->ci - 1;  /* previous function frame */
        int b = GETARG_B(i);
        if (b != 0) L->top = ra+b-1;
        lua_assert(L->ci->state & CI_HASFRAME);
        if (L->openupval) luaF_close(L, base);
        L->ci->state = CI_SAVEDPC;  /* deactivate current function */
        L->ci->u.l.savedpc = pc;
        /* previous function was running `here'? */
        if (!(ci->state & CI_CALLING)) {
          lua_assert((ci->state & CI_C) || ci->u.l.pc != &pc);
          return ra;  /* no: return */
        }
        else {  /* yes: continue its execution */
          int nresults;
          lua_assert(ttisfunction(ci->base - 1) && (ci->state & CI_SAVEDPC));
          lua_assert(GET_OPCODE(*(ci->u.l.savedpc - 1)) == OP_CALL);
          nresults = GETARG_C(*(ci->u.l.savedpc - 1)) - 1;
          luaD_poscall(L, nresults, ra);
          if (nresults >= 0) L->top = L->ci->top;
          goto retentry;
        }
      }
      case OP_FORLOOP: {
        lua_Number step, idx, limit;
        const TObject *plimit = ra+1;
        const TObject *pstep = ra+2;
        if (!ttisnumber(ra))
          luaG_runerror(L, "`for' initial value must be a number");
        if (!tonumber(plimit, ra+1))
          luaG_runerror(L, "`for' limit must be a number");
        if (!tonumber(pstep, ra+2))
          luaG_runerror(L, "`for' step must be a number");
        step = nvalue(pstep);
        idx = nvalue(ra) + step;  /* increment index */
        limit = nvalue(plimit);
        if (step > 0 ? idx <= limit : idx >= limit) {
          dojump(pc, GETARG_sBx(i));  /* jump back */
          chgnvalue(ra, idx);  /* update index */
        }
        break;
      }
      case OP_TFORLOOP: {
        int nvar = GETARG_C(i) + 1;
        StkId cb = ra + nvar + 2;  /* call base */
        setobjs2s(cb, ra);
        setobjs2s(cb+1, ra+1);
        setobjs2s(cb+2, ra+2);
        L->top = cb+3;  /* func. + 2 args (state and index) */
        luaD_call(L, cb, nvar);
        L->top = L->ci->top;
        ra = XRA(i) + 2;  /* final position of first result */
        cb = ra + nvar;
        do {  /* move results to proper positions */
          nvar--;
          setobjs2s(ra+nvar, cb+nvar);
        } while (nvar > 0);
        if (ttisnil(ra))  /* break loop? */
          pc++;  /* skip jump (break loop) */
        else
          dojump(pc, GETARG_sBx(*pc) + 1);  /* jump back */
        break;
      }
      case OP_TFORPREP: {  /* for compatibility only */
        if (ttistable(ra)) {
          setobjs2s(ra+1, ra);
          setobj2s(ra, luaH_getstr(hvalue(gt(L)), luaS_new(L, "next")));
        }
        dojump(pc, GETARG_sBx(i));
        break;
      }
      case OP_SETLIST:
      case OP_SETLISTO: {
        int bc;
        int n;
        Table *h;
        runtime_check(L, ttistable(ra));
        h = hvalue(ra);
        bc = GETARG_Bx(i);
        if (GET_OPCODE(i) == OP_SETLIST)
          n = (bc&(LFIELDS_PER_FLUSH-1)) + 1;
        else {
          n = L->top - ra - 1;
          L->top = L->ci->top;
        }
        bc &= ~(LFIELDS_PER_FLUSH-1);  /* bc = bc - bc%FPF */
        for (; n > 0; n--)
          setobj2t(luaH_setnum(L, h, bc+n), ra+n);  /* write barrier */
        break;
      }
      case OP_CLOSE: {
        luaF_close(L, ra);
        break;
      }
      case OP_CLOSURE: {
        Proto *p;
        Closure *ncl;
        int nup, j;
        p = cl->p->p[GETARG_Bx(i)];
        nup = p->nups;
        ncl = luaF_newLclosure(L, nup, &cl->g);
        ncl->l.p = p;
        for (j=0; j<nup; j++, pc++) {
          if (GET_OPCODE(*pc) == OP_GETUPVAL)
            ncl->l.upvals[j] = cl->upvals[GETARG_B(*pc)];
          else {
            lua_assert(GET_OPCODE(*pc) == OP_MOVE);
            ncl->l.upvals[j] = luaF_findupval(L, base + GETARG_B(*pc));
          }
        }
        setclvalue(ra, ncl);
        luaC_checkGC(L);
        break;
      }
    }
  }
}