lcode.c

世界上最快的脚本语言lua的源码

  }
  e->f = e->t = NO_JUMP;
  e->info = reg;
  e->k = VNONRELOC;
}


void luaK_exp2nextreg (FuncState *fs, expdesc *e) {
  luaK_dischargevars(fs, e);
  freeexp(fs, e);
  luaK_reserveregs(fs, 1);
  luaK_exp2reg(fs, e, fs->freereg - 1);
}


int luaK_exp2anyreg (FuncState *fs, expdesc *e) {
  luaK_dischargevars(fs, e);
  if (e->k == VNONRELOC) {
    if (!hasjumps(e)) return e->info;  /* exp is already in a register */ 
    if (e->info >= fs->nactvar) {  /* reg. is not a local? */
      luaK_exp2reg(fs, e, e->info);  /* put value on it */
      return e->info;
    }
  }
  luaK_exp2nextreg(fs, e);  /* default */
  return e->info;
}


void luaK_exp2val (FuncState *fs, expdesc *e) {
  if (hasjumps(e))
    luaK_exp2anyreg(fs, e);
  else
    luaK_dischargevars(fs, e);
}


int luaK_exp2RK (FuncState *fs, expdesc *e) {
  luaK_exp2val(fs, e);
  switch (e->k) {
    case VNIL: {
      if (fs->nk + MAXSTACK <= MAXARG_C) {  /* constant fit in argC? */
        e->info = nil_constant(fs);
        e->k = VK;
        return e->info + MAXSTACK;
      }
      else break;
    }
    case VK: {
      if (e->info + MAXSTACK <= MAXARG_C)  /* constant fit in argC? */
        return e->info + MAXSTACK;
      else break;
    }
    default: break;
  }
  /* not a constant in the right range: put it in a register */
  return luaK_exp2anyreg(fs, e);
}


void luaK_storevar (FuncState *fs, expdesc *var, expdesc *exp) {
  switch (var->k) {
    case VLOCAL: {
      freeexp(fs, exp);
      luaK_exp2reg(fs, exp, var->info);
      return;
    }
    case VUPVAL: {
      int e = luaK_exp2anyreg(fs, exp);
      luaK_codeABC(fs, OP_SETUPVAL, e, var->info, 0);
      break;
    }
    case VGLOBAL: {
      int e = luaK_exp2anyreg(fs, exp);
      luaK_codeABx(fs, OP_SETGLOBAL, e, var->info);
      break;
    }
    case VINDEXED: {
      int e = luaK_exp2RK(fs, exp);
      luaK_codeABC(fs, OP_SETTABLE, var->info, var->aux, e);
      break;
    }
    default: {
      lua_assert(0);  /* invalid var kind to store */
      break;
    }
  }
  freeexp(fs, exp);
}


void luaK_self (FuncState *fs, expdesc *e, expdesc *key) {
  int func;
  luaK_exp2anyreg(fs, e);
  freeexp(fs, e);
  func = fs->freereg;
  luaK_reserveregs(fs, 2);
  luaK_codeABC(fs, OP_SELF, func, e->info, luaK_exp2RK(fs, key));
  freeexp(fs, key);
  e->info = func;
  e->k = VNONRELOC;
}


static void invertjump (FuncState *fs, expdesc *e) {
  Instruction *pc = getjumpcontrol(fs, e->info);
  lua_assert(testOpMode(GET_OPCODE(*pc), OpModeT) &&
             GET_OPCODE(*pc) != OP_TEST);
  SETARG_A(*pc, !(GETARG_A(*pc)));
}


static int jumponcond (FuncState *fs, expdesc *e, int cond) {
  if (e->k == VRELOCABLE) {
    Instruction ie = getcode(fs, e);
    if (GET_OPCODE(ie) == OP_NOT) {
      fs->pc--;  /* remove previous OP_NOT */
      return luaK_condjump(fs, OP_TEST, NO_REG, GETARG_B(ie), !cond);
    }
    /* else go through */
  }
  discharge2anyreg(fs, e);
  freeexp(fs, e);
  return luaK_condjump(fs, OP_TEST, NO_REG, e->info, cond);
}


void luaK_goiftrue (FuncState *fs, expdesc *e) {
  int pc;  /* pc of last jump */
  luaK_dischargevars(fs, e);
  switch (e->k) {
    case VK: case VTRUE: {
      pc = NO_JUMP;  /* always true; do nothing */
      break;
    }
    case VFALSE: {
      pc = luaK_jump(fs);  /* always jump */
      break;
    }
    case VJMP: {
      invertjump(fs, e);
      pc = e->info;
      break;
    }
    default: {
      pc = jumponcond(fs, e, 0);
      break;
    }
  }
  luaK_concat(fs, &e->f, pc);  /* insert last jump in `f' list */
}


void luaK_goiffalse (FuncState *fs, expdesc *e) {
  int pc;  /* pc of last jump */
  luaK_dischargevars(fs, e);
  switch (e->k) {
    case VNIL: case VFALSE: {
      pc = NO_JUMP;  /* always false; do nothing */
      break;
    }
    case VTRUE: {
      pc = luaK_jump(fs);  /* always jump */
      break;
    }
    case VJMP: {
      pc = e->info;
      break;
    }
    default: {
      pc = jumponcond(fs, e, 1);
      break;
    }
  }
  luaK_concat(fs, &e->t, pc);  /* insert last jump in `t' list */
}


static void codenot (FuncState *fs, expdesc *e) {
  luaK_dischargevars(fs, e);
  switch (e->k) {
    case VNIL: case VFALSE: {
      e->k = VTRUE;
      break;
    }
    case VK: case VTRUE: {
      e->k = VFALSE;
      break;
    }
    case VJMP: {
      invertjump(fs, e);
      break;
    }
    case VRELOCABLE:
    case VNONRELOC: {
      discharge2anyreg(fs, e);
      freeexp(fs, e);
      e->info = luaK_codeABC(fs, OP_NOT, 0, e->info, 0);
      e->k = VRELOCABLE;
      break;
    }
    default: {
      lua_assert(0);  /* cannot happen */
      break;
    }
  }
  /* interchange true and false lists */
  { int temp = e->f; e->f = e->t; e->t = temp; }
}


void luaK_indexed (FuncState *fs, expdesc *t, expdesc *k) {
  t->aux = luaK_exp2RK(fs, k);
  t->k = VINDEXED;
}


void luaK_prefix (FuncState *fs, UnOpr op, expdesc *e) {
  if (op == OPR_MINUS) {
    luaK_exp2val(fs, e);
    if (e->k == VK && ttisnumber(&fs->f->k[e->info]))
      e->info = luaK_numberK(fs, -nvalue(&fs->f->k[e->info]));
    else {
      luaK_exp2anyreg(fs, e);
      freeexp(fs, e);
      e->info = luaK_codeABC(fs, OP_UNM, 0, e->info, 0);
      e->k = VRELOCABLE;
    }
  }
  else  /* op == NOT */
    codenot(fs, e);
}


void luaK_infix (FuncState *fs, BinOpr op, expdesc *v) {
  switch (op) {
    case OPR_AND: {
      luaK_goiftrue(fs, v);
      luaK_patchtohere(fs, v->t);
      v->t = NO_JUMP;
      break;
    }
    case OPR_OR: {
      luaK_goiffalse(fs, v);
      luaK_patchtohere(fs, v->f);
      v->f = NO_JUMP;
      break;
    }
    case OPR_CONCAT: {
      luaK_exp2nextreg(fs, v);  /* operand must be on the `stack' */
      break;
    }
    default: {
      luaK_exp2RK(fs, v);
      break;
    }
  }
}


static void codebinop (FuncState *fs, expdesc *res, BinOpr op,
                       int o1, int o2) {
  if (op <= OPR_POW) {  /* arithmetic operator? */
    OpCode opc = cast(OpCode, (op - OPR_ADD) + OP_ADD);  /* ORDER OP */
    res->info = luaK_codeABC(fs, opc, 0, o1, o2);
    res->k = VRELOCABLE;
  }
  else {  /* test operator */
    static const OpCode ops[] = {OP_EQ, OP_EQ, OP_LT, OP_LE, OP_LT, OP_LE};
    int cond = 1;
    if (op >= OPR_GT) {  /* `>' or `>='? */
      int temp;  /* exchange args and replace by `<' or `<=' */
      temp = o1; o1 = o2; o2 = temp;  /* o1 <==> o2 */
    }
    else if (op == OPR_NE) cond = 0;
    res->info = luaK_condjump(fs, ops[op - OPR_NE], cond, o1, o2);
    res->k = VJMP;
  }
}


void luaK_posfix (FuncState *fs, BinOpr op, expdesc *e1, expdesc *e2) {
  switch (op) {
    case OPR_AND: {
      lua_assert(e1->t == NO_JUMP);  /* list must be closed */
      luaK_dischargevars(fs, e2);
      luaK_concat(fs, &e1->f, e2->f);
      e1->k = e2->k; e1->info = e2->info; e1->aux = e2->aux; e1->t = e2->t;
      break;
    }
    case OPR_OR: {
      lua_assert(e1->f == NO_JUMP);  /* list must be closed */
      luaK_dischargevars(fs, e2);
      luaK_concat(fs, &e1->t, e2->t);
      e1->k = e2->k; e1->info = e2->info; e1->aux = e2->aux; e1->f = e2->f;
      break;
    }
    case OPR_CONCAT: {
      luaK_exp2val(fs, e2);
      if (e2->k == VRELOCABLE && GET_OPCODE(getcode(fs, e2)) == OP_CONCAT) {
        lua_assert(e1->info == GETARG_B(getcode(fs, e2))-1);
        freeexp(fs, e1);
        SETARG_B(getcode(fs, e2), e1->info);
        e1->k = e2->k; e1->info = e2->info;
      }
      else {
        luaK_exp2nextreg(fs, e2);
        freeexp(fs, e2);
        freeexp(fs, e1);
        e1->info = luaK_codeABC(fs, OP_CONCAT, 0, e1->info, e2->info);
        e1->k = VRELOCABLE;
      }
      break;
    }
    default: {
      int o1 = luaK_exp2RK(fs, e1);
      int o2 = luaK_exp2RK(fs, e2);
      freeexp(fs, e2);
      freeexp(fs, e1);
      codebinop(fs, e1, op, o1, o2);
    }
  }
}


void luaK_fixline (FuncState *fs, int line) {
  fs->f->lineinfo[fs->pc - 1] = line;
}


int luaK_code (FuncState *fs, Instruction i, int line) {
  Proto *f = fs->f;
  luaK_dischargejpc(fs);  /* `pc' will change */
  /* put new instruction in code array */
  luaM_growvector(fs->L, f->code, fs->pc, f->sizecode, Instruction,
                  MAX_INT, "code size overflow");
  f->code[fs->pc] = i;
  /* save corresponding line information */
  luaM_growvector(fs->L, f->lineinfo, fs->pc, f->sizelineinfo, int,
                  MAX_INT, "code size overflow");
  f->lineinfo[fs->pc] = line;
  return fs->pc++;
}


int luaK_codeABC (FuncState *fs, OpCode o, int a, int b, int c) {
  lua_assert(getOpMode(o) == iABC);
  return luaK_code(fs, CREATE_ABC(o, a, b, c), fs->ls->lastline);
}


int luaK_codeABx (FuncState *fs, OpCode o, int a, unsigned int bc) {
  lua_assert(getOpMode(o) == iABx || getOpMode(o) == iAsBx);
  return luaK_code(fs, CREATE_ABx(o, a, bc), fs->ls->lastline);
}