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ffi/target/release/build/mlua-sys-6a99a2ae50f12319/out/luajit-build/build/src/lj_parse.c  view on Meta::CPAN

      *ip = BCINS_AD(cond ? BC_ISF : BC_IST, 0, bc_d(*ip));
      return bcemit_jmp(fs);
    }
  }
  if (e->k != VNONRELOC) {
    bcreg_reserve(fs, 1);
    expr_toreg_nobranch(fs, e, fs->freereg-1);
  }
  bcemit_AD(fs, cond ? BC_ISTC : BC_ISFC, NO_REG, e->u.s.info);
  pc = bcemit_jmp(fs);
  expr_free(fs, e);
  return pc;
}

/* Emit branch on true condition. */
static void bcemit_branch_t(FuncState *fs, ExpDesc *e)
{
  BCPos pc;
  expr_discharge(fs, e);
  if (e->k == VKSTR || e->k == VKNUM || e->k == VKTRUE)
    pc = NO_JMP;  /* Never jump. */
  else if (e->k == VJMP)
    invertcond(fs, e), pc = e->u.s.info;
  else if (e->k == VKFALSE || e->k == VKNIL)
    expr_toreg_nobranch(fs, e, NO_REG), pc = bcemit_jmp(fs);
  else
    pc = bcemit_branch(fs, e, 0);
  jmp_append(fs, &e->f, pc);
  jmp_tohere(fs, e->t);
  e->t = NO_JMP;
}

/* Emit branch on false condition. */
static void bcemit_branch_f(FuncState *fs, ExpDesc *e)
{
  BCPos pc;
  expr_discharge(fs, e);
  if (e->k == VKNIL || e->k == VKFALSE)
    pc = NO_JMP;  /* Never jump. */
  else if (e->k == VJMP)
    pc = e->u.s.info;
  else if (e->k == VKSTR || e->k == VKNUM || e->k == VKTRUE)
    expr_toreg_nobranch(fs, e, NO_REG), pc = bcemit_jmp(fs);
  else
    pc = bcemit_branch(fs, e, 1);
  jmp_append(fs, &e->t, pc);
  jmp_tohere(fs, e->f);
  e->f = NO_JMP;
}

/* -- Bytecode emitter for operators -------------------------------------- */

/* Try constant-folding of arithmetic operators. */
static int foldarith(BinOpr opr, ExpDesc *e1, ExpDesc *e2)
{
  TValue o;
  lua_Number n;
  if (!expr_isnumk_nojump(e1) || !expr_isnumk_nojump(e2)) return 0;
  n = lj_vm_foldarith(expr_numberV(e1), expr_numberV(e2), (int)opr-OPR_ADD);
  setnumV(&o, n);
  if (tvisnan(&o) || tvismzero(&o)) return 0;  /* Avoid NaN and -0 as consts. */
  if (LJ_DUALNUM) {
    int32_t k = lj_num2int(n);
    if ((lua_Number)k == n) {
      setintV(&e1->u.nval, k);
      return 1;
    }
  }
  setnumV(&e1->u.nval, n);
  return 1;
}

/* Emit arithmetic operator. */
static void bcemit_arith(FuncState *fs, BinOpr opr, ExpDesc *e1, ExpDesc *e2)
{
  BCReg rb, rc, t;
  uint32_t op;
  if (foldarith(opr, e1, e2))
    return;
  if (opr == OPR_POW) {
    op = BC_POW;
    rc = expr_toanyreg(fs, e2);
    rb = expr_toanyreg(fs, e1);
  } else {
    op = opr-OPR_ADD+BC_ADDVV;
    /* Must discharge 2nd operand first since VINDEXED might free regs. */
    expr_toval(fs, e2);
    if (expr_isnumk(e2) && (rc = const_num(fs, e2)) <= BCMAX_C)
      op -= BC_ADDVV-BC_ADDVN;
    else
      rc = expr_toanyreg(fs, e2);
    /* 1st operand discharged by bcemit_binop_left, but need KNUM/KSHORT. */
    lj_assertFS(expr_isnumk(e1) || e1->k == VNONRELOC,
		"bad expr type %d", e1->k);
    expr_toval(fs, e1);
    /* Avoid two consts to satisfy bytecode constraints. */
    if (expr_isnumk(e1) && !expr_isnumk(e2) &&
	(t = const_num(fs, e1)) <= BCMAX_B) {
      rb = rc; rc = t; op -= BC_ADDVV-BC_ADDNV;
    } else {
      rb = expr_toanyreg(fs, e1);
    }
  }
  /* Using expr_free might cause asserts if the order is wrong. */
  if (e1->k == VNONRELOC && e1->u.s.info >= fs->nactvar) fs->freereg--;
  if (e2->k == VNONRELOC && e2->u.s.info >= fs->nactvar) fs->freereg--;
  e1->u.s.info = bcemit_ABC(fs, op, 0, rb, rc);
  e1->k = VRELOCABLE;
}

/* Emit comparison operator. */
static void bcemit_comp(FuncState *fs, BinOpr opr, ExpDesc *e1, ExpDesc *e2)
{
  ExpDesc *eret = e1;
  BCIns ins;
  expr_toval(fs, e1);
  if (opr == OPR_EQ || opr == OPR_NE) {
    BCOp op = opr == OPR_EQ ? BC_ISEQV : BC_ISNEV;
    BCReg ra;
    if (expr_isk(e1)) { e1 = e2; e2 = eret; }  /* Need constant in 2nd arg. */
    ra = expr_toanyreg(fs, e1);  /* First arg must be in a reg. */