text: /*
  ** Fast function call recorder.
  ** Copyright (C) 2005-2014 Mike Pall. See Copyright Notice in luajit.h
  **
  ** Lua 5.2 string semantics and string.match() compiling
  ** Copyright (C) 2014 Karel Tuma. See Copyright Notice in luajit.h
  */
  
  #define lj_ffrecord_c
  #define LUA_CORE
  
  #include "lj_obj.h"
  
  #if LJ_HASJIT
  
  #include "lj_err.h"
  #include "lj_str.h"
  #include "lj_tab.h"
  #include "lj_frame.h"
  #include "lj_bc.h"
  #include "lj_ff.h"
  #include "lj_ir.h"
  #include "lj_jit.h"
  #include "lj_ircall.h"
  #include "lj_iropt.h"
  #include "lj_trace.h"
  #include "lj_record.h"
  #include "lj_ffrecord.h"
  #include "lj_crecord.h"
  #include "lj_dispatch.h"
  #include "lj_vm.h"
  #include "lj_strscan.h"
  #include "lj_strfmt.h"
  
  /* Some local macros to save typing. Undef'd at the end. */
  #define IR(ref)			(&J->cur.ir[(ref)])
  
  /* Pass IR on to next optimization in chain (FOLD). */
  #define emitir(ot, a, b)	(lj_ir_set(J, (ot), (a), (b)), lj_opt_fold(J))
  
  /* -- Fast function recording handlers ------------------------------------ */
  
  /* Conventions for fast function call handlers:
  **
  ** The argument slots start at J->base[0]. All of them are guaranteed to be
  ** valid and type-specialized references. J->base[J->maxslot] is set to 0
  ** as a sentinel. The runtime argument values start at rd->argv[0].
  **
  ** In general fast functions should check for presence of all of their
  ** arguments and for the correct argument types. Some simplifications
  ** are allowed if the interpreter throws instead. But even if recording
  ** is aborted, the generated IR must be consistent (no zero-refs).
  **
  ** The number of results in rd->nres is set to 1. Handlers that return
  ** a different number of results need to override it. A negative value
  ** prevents return processing (e.g. for pending calls).
  **
  ** Results need to be stored starting at J->base[0]. Return processing
  ** moves them to the right slots later.
  **
  ** The per-ffid auxiliary data is the value of the 2nd part of the
  ** LJLIB_REC() annotation. This allows handling similar functionality
  ** in a common handler.
  */
  
  /* Type of handler to record a fast function. */
  typedef void (LJ_FASTCALL *RecordFunc)(jit_State *J, RecordFFData *rd);
  
  /* Get runtime value of int argument. */
  static int32_t argv2int(jit_State *J, TValue *o)
  {
    if (!lj_strscan_numberobj(o))
      lj_trace_err(J, LJ_TRERR_BADTYPE);
    return tvisint(o) ? intV(o) : lj_num2int(numV(o));
  }
  
  /* Get runtime value of string argument. */
  static GCstr *argv2str(jit_State *J, TValue *o)
  {
    if (LJ_LIKELY(tvisstr(o))) {
      return strV(o);
    } else {
      GCstr *s;
      if (!tvisnumber(o))
        lj_trace_err(J, LJ_TRERR_BADTYPE);
      s = lj_strfmt_number(J->L, o);
      setstrV(J->L, o, s);
      return s;
    }
  }
  
  /* Return number of results wanted by caller. */
  static ptrdiff_t results_wanted(jit_State *J)
  {
    TValue *frame = J->L->base-1;
    if (frame_islua(frame))
      return (ptrdiff_t)bc_b(frame_pc(frame)[-1]) - 1;
    else
      return -1;
  }
  
  /* Trace stitching: add continuation below frame to start a new trace. */
  static void recff_stitch(jit_State *J)
  {
    ASMFunction cont = lj_cont_stitch;
    lua_State *L = J->L;
    TValue *base = L->base;
    BCReg nslot = J->maxslot + 1 + LJ_FR2;
    TValue *nframe = base + 1 + LJ_FR2;
    const BCIns *pc = frame_pc(base-1);
    TValue *pframe = frame_prevl(base-1);
  
    /* Move func + args up in Lua stack and insert continuation. */
    memmove(&base[1], &base[-1-LJ_FR2], sizeof(TValue)*nslot);
    setframe_ftsz(nframe, ((char *)nframe - (char *)pframe) + FRAME_CONT);
    setcont(base-LJ_FR2, cont);
    setframe_pc(base, pc);
    setnilV(base-1-LJ_FR2);  /* Incorrect, but rec_check_slots() won't run anymore. */
    L->base += 2 + LJ_FR2;
    L->top += 2 + LJ_FR2;
  
    /* Ditto for the IR. */
    memmove(&J->base[1], &J->base[-1-LJ_FR2], sizeof(TRef)*nslot);
  #if LJ_FR2
    J->base[2] = TREF_FRAME;
    J->base[-1] = lj_ir_k64(J, IR_KNUM, u64ptr(contptr(cont)));
    J->base[0] = lj_ir_k64(J, IR_KNUM, u64ptr(pc)) | TREF_CONT;
  #else
    J->base[0] = lj_ir_kptr(J, contptr(cont)) | TREF_CONT;
  #endif
    J->ktrace = tref_ref((J->base[-1-LJ_FR2] = lj_ir_ktrace(J)));
    J->base += 2 + LJ_FR2;
    J->baseslot += 2 + LJ_FR2;
    J->framedepth++;
  
    lj_record_stop(J, LJ_TRLINK_STITCH, 0);
  
    /* Undo Lua stack changes. */
    memmove(&base[-1-LJ_FR2], &base[1], sizeof(TValue)*nslot);
    setframe_pc(base-1, pc);
    L->base -= 2 + LJ_FR2;
    L->top -= 2 + LJ_FR2;
  }
  
  /* Fallback handler for fast functions that are not recorded (yet). */
  static void LJ_FASTCALL recff_nyi(jit_State *J, RecordFFData *rd)
  {
    if (J->cur.nins < (IRRef)J->param[JIT_P_minstitch] + REF_BASE) {
      lj_trace_err_info(J, LJ_TRERR_TRACEUV);
    } else {
      /* Can only stitch from Lua call. */
      if (J->framedepth && frame_islua(J->L->base-1)) {
        BCOp op = bc_op(*frame_pc(J->L->base-1));
        /* Stitched trace cannot start with *M op with variable # of args. */
        if (!(op == BC_CALLM || op == BC_CALLMT ||
  	    op == BC_RETM || op == BC_TSETM)) {
  	switch (J->fn->c.ffid) {
  	case FF_error:
  	case FF_debug_sethook:
  	case FF_jit_flush:
  	  break;  /* Don't stitch across special builtins. */
  	default:
            if (!(J->flags & JIT_F_OPT_STITCH))
              break;
  	  recff_stitch(J);  /* Use trace stitching. */
  	  rd->nres = -1;
  	  return;
  	}
        }
      }
      /* Otherwise stop trace and return to interpreter. */
      lj_record_stop(J, LJ_TRLINK_RETURN, 0);
      rd->nres = -1;
    }
  }
  
  /* Fallback handler for unsupported variants of fast functions. */
  #define recff_nyiu	recff_nyi
  
  /* Must stop the trace for classic C functions with arbitrary side-effects. */
  #define recff_c		recff_nyi
  
  /* Emit BUFHDR for the global temporary buffer. */
  static TRef recff_bufhdr(jit_State *J)
  {
    return emitir(IRT(IR_BUFHDR, IRT_PGC),
  		lj_ir_kptr(J, &J2G(J)->tmpbuf), IRBUFHDR_RESET);
  }
  
  /* -- Base library fast functions ----------------------------------------- */
  
  static void LJ_FASTCALL recff_assert(jit_State *J, RecordFFData *rd)
  {
    /* Arguments already specialized. The interpreter throws for nil/false. */
    rd->nres = J->maxslot;  /* Pass through all arguments. */
  }
  
  static void LJ_FASTCALL recff_type(jit_State *J, RecordFFData *rd)
  {
    /* Arguments already specialized. Result is a constant string. Neat, huh? */
    uint32_t t;
    if (tvisnumber(&rd->argv[0]))
      t = ~LJ_TNUMX;
    else if (LJ_64 && !LJ_GC64 && tvislightud(&rd->argv[0]))
      t = ~LJ_TLIGHTUD;
    else
      t = ~itype(&rd->argv[0]);
    J->base[0] = lj_ir_kstr(J, strV(&J->fn->c.upvalue[t]));
    UNUSED(rd);
  }
  
  static void LJ_FASTCALL recff_getmetatable(jit_State *J, RecordFFData *rd)
  {
    TRef tr = J->base[0];
    if (tr) {
      RecordIndex ix;
      ix.tab = tr;
      copyTV(J->L, &ix.tabv, &rd->argv[0]);
      if (lj_record_mm_lookup(J, &ix, MM_metatable))
        J->base[0] = ix.mobj;
      else
        J->base[0] = ix.mt;
    }  /* else: Interpreter will throw. */
  }
  
  static void setmetatable_gc_guard(jit_State *J, RecordFFData *rd)
  {
    RecordIndex mix;
    GCstr *mmstr = mmname_str(J2G(J), MM_gc);
  
    /* Look for __gc */
    copyTV(J->L, &mix.tabv, &rd->argv[1]);
    setstrV(J->L, &mix.keyv, mmstr);
    mix.tab = J->base[1];
    mix.key = lj_ir_kstr(J, mmstr);
    mix.val = 0; /* Load */
    mix.idxchain = 0;
    if (!tref_isnil(lj_record_idx(J, &mix)))
      lj_ir_call(J, IRCALL_lj_gc_tab_finalized, J->base[0]);
  }
  
  static void LJ_FASTCALL recff_setmetatable(jit_State *J, RecordFFData *rd)
  {
    TRef tr = J->base[0];
    TRef mt = J->base[1];
    if (tref_istab(tr) && (tref_istab(mt) || (mt && tref_isnil(mt)))) {
      TRef fref, mtref;
      RecordIndex ix;
      ix.tab = tr;
      copyTV(J->L, &ix.tabv, &rd->argv[0]);
      lj_record_mm_lookup(J, &ix, MM_metatable); /* Guard for no __metatable. */
      fref = emitir(IRT(IR_FREF, IRT_PGC), tr, IRFL_TAB_META);
      mtref = tref_isnil(mt) ? lj_ir_knull(J, IRT_TAB) : mt;
      emitir(IRT(IR_FSTORE, IRT_TAB), fref, mtref);
      if (!tref_isnil(mt)) {
        setmetatable_gc_guard(J, rd);
        emitir(IRT(IR_TBAR, IRT_TAB), tr, 0);
      }
      J->base[0] = tr;
      J->needsnap = 1;
    }  /* else: Interpreter will throw. */
  }
  
  static void LJ_FASTCALL recff_rawget(jit_State *J, RecordFFData *rd)
  {
    RecordIndex ix;
    ix.tab = J->base[0]; ix.key = J->base[1];
    if (tref_istab(ix.tab) && ix.key) {
      ix.val = 0; ix.idxchain = 0;
      settabV(J->L, &ix.tabv, tabV(&rd->argv[0]));
      copyTV(J->L, &ix.keyv, &rd->argv[1]);
      J->base[0] = lj_record_idx(J, &ix);
    }  /* else: Interpreter will throw. */
  }
  
  static void LJ_FASTCALL recff_rawset(jit_State *J, RecordFFData *rd)
  {
    RecordIndex ix;
    ix.tab = J->base[0]; ix.key = J->base[1]; ix.val = J->base[2];
    if (tref_istab(ix.tab) && ix.key && ix.val) {
      ix.idxchain = 0;
      settabV(J->L, &ix.tabv, tabV(&rd->argv[0]));
      copyTV(J->L, &ix.keyv, &rd->argv[1]);
      copyTV(J->L, &ix.valv, &rd->argv[2]);
      lj_record_idx(J, &ix);
      /* Pass through table at J->base[0] as result. */
    }  /* else: Interpreter will throw. */
  }
  
  static void LJ_FASTCALL recff_rawequal(jit_State *J, RecordFFData *rd)
  {
    TRef tra = J->base[0];
    TRef trb = J->base[1];
    if (tra && trb) {
      int diff = lj_record_objcmp(J, tra, trb, &rd->argv[0], &rd->argv[1]);
      J->base[0] = diff ? TREF_FALSE : TREF_TRUE;
    }  /* else: Interpreter will throw. */
  }
  
  static void LJ_FASTCALL recff_rawlen(jit_State *J, RecordFFData *rd)
  {
    TRef tr = J->base[0];
    if (tref_isstr(tr))
      J->base[0] = emitir(IRTI(IR_FLOAD), tr, IRFL_STR_LEN);
    else if (tref_istab(tr))
      J->base[0] = emitir(IRTI(IR_ALEN), tr, TREF_NIL);
    /* else: Interpreter will throw. */
    UNUSED(rd);
  }
  
  /* Determine mode of select() call. */
  int32_t lj_ffrecord_select_mode(jit_State *J, TRef tr, TValue *tv)
  {
    if (tref_isstr(tr) && *strVdata(tv) == '#') {  /* select('#', ...) */
      if (strV(tv)->len == 1) {
        emitir(IRTG(IR_EQ, IRT_STR), tr, lj_ir_kstr(J, strV(tv)));
      } else {
        TRef trptr = emitir(IRT(IR_STRREF, IRT_PGC), tr, lj_ir_kint(J, 0));
        TRef trchar = emitir(IRT(IR_XLOAD, IRT_U8), trptr, IRXLOAD_READONLY);
        emitir(IRTG(IR_EQ, IRT_INT), trchar, lj_ir_kint(J, '#'));
      }
      return 0;
    } else {  /* select(n, ...) */
      int32_t start = argv2int(J, tv);
      if (start == 0) lj_trace_err(J, LJ_TRERR_BADTYPE);  /* A bit misleading. */
      return start;
    }
  }
  
  static void LJ_FASTCALL recff_select(jit_State *J, RecordFFData *rd)
  {
    TRef tr = J->base[0];
    if (tr) {
      ptrdiff_t start = lj_ffrecord_select_mode(J, tr, &rd->argv[0]);
      if (start == 0) {  /* select('#', ...) */
        J->base[0] = lj_ir_kint(J, J->maxslot - 1);
      } else if (tref_isk(tr)) {  /* select(k, ...) */
        ptrdiff_t n = (ptrdiff_t)J->maxslot;
        if (start < 0) start += n;
        else if (start > n) start = n;
        rd->nres = n - start;
        if (start >= 1) {
  	ptrdiff_t i;
  	for (i = 0; i < n - start; i++)
  	  J->base[i] = J->base[start+i];
        }  /* else: Interpreter will throw. */
      } else {
        recff_nyiu(J, rd);
        return;
      }
    }  /* else: Interpreter will throw. */
  }
  
  static void LJ_FASTCALL recff_tonumber(jit_State *J, RecordFFData *rd)
  {
    TRef tr = J->base[0];
    TRef base = J->base[1];
    if (tr && !tref_isnil(base)) {
      base = lj_opt_narrow_toint(J, base);
      if (!tref_isk(base) || IR(tref_ref(base))->i != 10) {
        recff_nyiu(J, rd);
        return;
      }
    }
    if (tref_isnumber_str(tr)) {
      if (tref_isstr(tr)) {
        TValue tmp;
        if (!lj_strscan_num(strV(&rd->argv[0]), &tmp)) {
  	recff_nyiu(J, rd);  /* Would need an inverted STRTO for this case. */
  	return;
        }
        tr = emitir(IRTG(IR_STRTO, IRT_NUM), tr, 0);
      }
  #if LJ_HASFFI
    } else if (tref_iscdata(tr)) {
      lj_crecord_tonumber(J, rd);
      return;
  #endif
    } else {
      tr = TREF_NIL;
    }
    J->base[0] = tr;
    UNUSED(rd);
  }
  
  static TValue *recff_metacall_cp(lua_State *L, lua_CFunction dummy, void *ud)
  {
    jit_State *J = (jit_State *)ud;
    lj_record_tailcall(J, 0, 1);
    UNUSED(L); UNUSED(dummy);
    return NULL;
  }
  
  static int recff_metacall(jit_State *J, RecordFFData *rd, MMS mm)
  {
    RecordIndex ix;
    ix.tab = J->base[0];
    copyTV(J->L, &ix.tabv, &rd->argv[0]);
    if (lj_record_mm_lookup(J, &ix, mm)) {  /* Has metamethod? */
      int errcode;
      TValue argv0;
      /* Temporarily insert metamethod below object. */
      J->base[1+LJ_FR2] = J->base[0];
      J->base[0] = ix.mobj;
      copyTV(J->L, &argv0, &rd->argv[0]);
      copyTV(J->L, &rd->argv[1+LJ_FR2], &rd->argv[0]);
      copyTV(J->L, &rd->argv[0], &ix.mobjv);
      /* Need to protect lj_record_tailcall because it may throw. */
      errcode = lj_vm_cpcall(J->L, NULL, J, recff_metacall_cp);
      /* Always undo Lua stack changes to avoid confusing the interpreter. */
      copyTV(J->L, &rd->argv[0], &argv0);
      if (errcode)
        lj_err_throw(J->L, errcode);  /* Propagate errors. */
      rd->nres = -1;  /* Pending call. */
      return 1;  /* Tailcalled to metamethod. */
    }
    return 0;
  }
  
  static void LJ_FASTCALL recff_tostring(jit_State *J, RecordFFData *rd)
  {
    TRef tr = J->base[0];
    if (tref_isstr(tr)) {
      /* Ignore __tostring in the string base metatable. */
      /* Pass on result in J->base[0]. */
    } else if (tr && !recff_metacall(J, rd, MM_tostring)) {
      if (tref_isnumber(tr)) {
        J->base[0] = emitir(IRT(IR_TOSTR, IRT_STR), tr,
  			  tref_isnum(tr) ? IRTOSTR_NUM : IRTOSTR_INT);
      } else if (tref_ispri(tr)) {
        J->base[0] = lj_ir_kstr(J, lj_strfmt_obj(J->L, &rd->argv[0]));
      } else {
        recff_nyiu(J, rd);
        return;
      }
    }
  }
  
  static void LJ_FASTCALL recff_ipairs_aux(jit_State *J, RecordFFData *rd)
  {
    RecordIndex ix;
    ix.tab = J->base[0];
    if (tref_istab(ix.tab)) {
      if (!tvisnumber(&rd->argv[1]))  /* No support for string coercion. */
        lj_trace_err(J, LJ_TRERR_BADTYPE);
      setintV(&ix.keyv, numberVint(&rd->argv[1])+1);
      settabV(J->L, &ix.tabv, tabV(&rd->argv[0]));
      ix.val = 0; ix.idxchain = 0;
      ix.key = lj_opt_narrow_toint(J, J->base[1]);
      J->base[0] = ix.key = emitir(IRTI(IR_ADD), ix.key, lj_ir_kint(J, 1));
      J->base[1] = lj_record_idx(J, &ix);
      rd->nres = tref_isnil(J->base[1]) ? 0 : 2;
    }  /* else: Interpreter will throw. */
  }
  
  static void LJ_FASTCALL recff_xpairs(jit_State *J, RecordFFData *rd)
  {
    TRef tr = J->base[0];
    if (!recff_metacall(J, rd, MM_pairs + rd->data)) {
      if (tref_istab(tr)) {
        J->base[0] = lj_ir_kfunc(J, funcV(&J->fn->c.upvalue[0]));
        J->base[1] = tr;
        J->base[2] = rd->data ? lj_ir_kint(J, 0) : TREF_NIL;
        rd->nres = 3;
      }  /* else: Interpreter will throw. */
    }
  }
  
  static void LJ_FASTCALL recff_pcall(jit_State *J, RecordFFData *rd)
  {
    if (J->maxslot >= 1) {
  #if LJ_FR2
      /* Shift function arguments up. */
      memmove(J->base + 1, J->base, sizeof(TRef) * J->maxslot);
  #endif
      lj_record_call(J, 0, J->maxslot - 1);
      rd->nres = -1;  /* Pending call. */
    }  /* else: Interpreter will throw. */
  }
  
  static TValue *recff_xpcall_cp(lua_State *L, lua_CFunction dummy, void *ud)
  {
    jit_State *J = (jit_State *)ud;
    lj_record_call(J, 1, J->maxslot - 2);
    UNUSED(L); UNUSED(dummy);
    return NULL;
  }
  
  static void LJ_FASTCALL recff_xpcall(jit_State *J, RecordFFData *rd)
  {
    if (J->maxslot >= 2) {
      TValue argv0, argv1;
      TRef tmp;
      int errcode;
      /* Swap function and traceback. */
      tmp = J->base[0]; J->base[0] = J->base[1]; J->base[1] = tmp;
      copyTV(J->L, &argv0, &rd->argv[0]);
      copyTV(J->L, &argv1, &rd->argv[1]);
      copyTV(J->L, &rd->argv[0], &argv1);
      copyTV(J->L, &rd->argv[1], &argv0);
  #if LJ_FR2
      /* Shift function arguments up. */
      memmove(J->base + 2, J->base + 1, sizeof(TRef) * (J->maxslot-1));
  #endif
      /* Need to protect lj_record_call because it may throw. */
      errcode = lj_vm_cpcall(J->L, NULL, J, recff_xpcall_cp);
      /* Always undo Lua stack swap to avoid confusing the interpreter. */
      copyTV(J->L, &rd->argv[0], &argv0);
      copyTV(J->L, &rd->argv[1], &argv1);
      if (errcode)
        lj_err_throw(J->L, errcode);  /* Propagate errors. */
      rd->nres = -1;  /* Pending call. */
    }  /* else: Interpreter will throw. */
  }
  
  static void LJ_FASTCALL recff_getfenv(jit_State *J, RecordFFData *rd)
  {
    TRef tr = J->base[0];
    /* Only support getfenv(0) for now. */
    if (tref_isint(tr) && tref_isk(tr) && IR(tref_ref(tr))->i == 0) {
      TRef trl = emitir(IRT(IR_LREF, IRT_THREAD), 0, 0);
      J->base[0] = emitir(IRT(IR_FLOAD, IRT_TAB), trl, IRFL_THREAD_ENV);
      return;
    }
    recff_nyiu(J, rd);
  }
  
  /* -- Math library fast functions ----------------------------------------- */
  
  static void LJ_FASTCALL recff_math_abs(jit_State *J, RecordFFData *rd)
  {
    TRef tr = lj_ir_tonum(J, J->base[0]);
    J->base[0] = emitir(IRTN(IR_ABS), tr, lj_ir_ksimd(J, LJ_KSIMD_ABS));
    UNUSED(rd);
  }
  
  /* Record rounding functions math.floor and math.ceil. */
  static void LJ_FASTCALL recff_math_round(jit_State *J, RecordFFData *rd)
  {
    TRef tr = J->base[0];
    if (!tref_isinteger(tr)) {  /* Pass through integers unmodified. */
      tr = emitir(IRTN(IR_FPMATH), lj_ir_tonum(J, tr), rd->data);
      /* Result is integral (or NaN/Inf), but may not fit an int32_t. */
      if (LJ_DUALNUM) {  /* Try to narrow using a guarded conversion to int. */
        lua_Number n = lj_vm_foldfpm(numberVnum(&rd->argv[0]), rd->data);
        if (n == (lua_Number)lj_num2int(n))
  	tr = emitir(IRTGI(IR_CONV), tr, IRCONV_INT_NUM|IRCONV_CHECK);
      }
      J->base[0] = tr;
    }
  }
  
  /* Record unary math.* functions, mapped to IR_FPMATH opcode. */
  static void LJ_FASTCALL recff_math_unary(jit_State *J, RecordFFData *rd)
  {
    J->base[0] = emitir(IRTN(IR_FPMATH), lj_ir_tonum(J, J->base[0]), rd->data);
  }
  
  /* Record math.log. */
  static void LJ_FASTCALL recff_math_log(jit_State *J, RecordFFData *rd)
  {
    TRef tr = lj_ir_tonum(J, J->base[0]);
    if (J->base[1]) {
  #ifdef LUAJIT_NO_LOG2
      uint32_t fpm = IRFPM_LOG;
  #else
      uint32_t fpm = IRFPM_LOG2;
  #endif
      TRef trb = lj_ir_tonum(J, J->base[1]);
      tr = emitir(IRTN(IR_FPMATH), tr, fpm);
      trb = emitir(IRTN(IR_FPMATH), trb, fpm);
      trb = emitir(IRTN(IR_DIV), lj_ir_knum_one(J), trb);
      tr = emitir(IRTN(IR_MUL), tr, trb);
    } else {
      tr = emitir(IRTN(IR_FPMATH), tr, IRFPM_LOG);
    }
    J->base[0] = tr;
    UNUSED(rd);
  }
  
  /* Record math.atan2. */
  static void LJ_FASTCALL recff_math_atan2(jit_State *J, RecordFFData *rd)
  {
    TRef tr = lj_ir_tonum(J, J->base[0]);
    TRef tr2 = lj_ir_tonum(J, J->base[1]);
    J->base[0] = lj_ir_call(J, IRCALL_atan2, tr, tr2);
    UNUSED(rd);
  }
  
  /* Record math.ldexp. */
  static void LJ_FASTCALL recff_math_ldexp(jit_State *J, RecordFFData *rd)
  {
    TRef tr = lj_ir_tonum(J, J->base[0]);
  #if LJ_TARGET_X86ORX64
    TRef tr2 = lj_ir_tonum(J, J->base[1]);
  #else
    TRef tr2 = lj_opt_narrow_toint(J, J->base[1]);
  #endif
    J->base[0] = emitir(IRTN(IR_LDEXP), tr, tr2);
    UNUSED(rd);
  }
  
  static void LJ_FASTCALL recff_math_call(jit_State *J, RecordFFData *rd)
  {
    TRef tr = lj_ir_tonum(J, J->base[0]);
    J->base[0] = emitir(IRTN(IR_CALLN), tr, rd->data);
  }
  
  static void LJ_FASTCALL recff_math_pow(jit_State *J, RecordFFData *rd)
  {
    J->base[0] = lj_opt_narrow_pow(J, J->base[0], J->base[1],
  				 &rd->argv[0], &rd->argv[1]);
    UNUSED(rd);
  }
  
  static void LJ_FASTCALL recff_math_minmax(jit_State *J, RecordFFData *rd)
  {
    TRef tr = lj_ir_tonumber(J, J->base[0]);
    uint32_t op = rd->data;
    BCReg i;
    for (i = 1; J->base[i] != 0; i++) {
      TRef tr2 = lj_ir_tonumber(J, J->base[i]);
      IRType t = IRT_INT;
      if (!(tref_isinteger(tr) && tref_isinteger(tr2))) {
        if (tref_isinteger(tr)) tr = emitir(IRTN(IR_CONV), tr, IRCONV_NUM_INT);
        if (tref_isinteger(tr2)) tr2 = emitir(IRTN(IR_CONV), tr2, IRCONV_NUM_INT);
        t = IRT_NUM;
      }
      tr = emitir(IRT(op, t), tr, tr2);
    }
    J->base[0] = tr;
  }
  
  static void LJ_FASTCALL recff_math_random(jit_State *J, RecordFFData *rd)
  {
    GCudata *ud = udataV(&J->fn->c.upvalue[0]);
    TRef tr, one;
    lj_ir_kgc(J, obj2gco(ud), IRT_UDATA);  /* Prevent collection. */
    tr = lj_ir_call(J, IRCALL_lj_prng_u64d, lj_ir_kptr(J, uddata(ud)));
    one = lj_ir_knum_one(J);
    tr = emitir(IRTN(IR_SUB), tr, one);
    if (J->base[0]) {
      TRef tr1 = lj_ir_tonum(J, J->base[0]);
      if (J->base[1]) {  /* d = floor(d*(r2-r1+1.0)) + r1 */
        TRef tr2 = lj_ir_tonum(J, J->base[1]);
        tr2 = emitir(IRTN(IR_SUB), tr2, tr1);
        tr2 = emitir(IRTN(IR_ADD), tr2, one);
        tr = emitir(IRTN(IR_MUL), tr, tr2);
        tr = emitir(IRTN(IR_FPMATH), tr, IRFPM_FLOOR);
        tr = emitir(IRTN(IR_ADD), tr, tr1);
      } else {  /* d = floor(d*r1) + 1.0 */
        tr = emitir(IRTN(IR_MUL), tr, tr1);
        tr = emitir(IRTN(IR_FPMATH), tr, IRFPM_FLOOR);
        tr = emitir(IRTN(IR_ADD), tr, one);
      }
    }
    J->base[0] = tr;
    UNUSED(rd);
  }
  
  /* -- Bit library fast functions ------------------------------------------ */
  
  /* Record bit.tobit. */
  static void LJ_FASTCALL recff_bit_tobit(jit_State *J, RecordFFData *rd)
  {
    TRef tr = J->base[0];
  #if LJ_HASFFI
    if (tref_iscdata(tr)) { recff_bit64_tobit(J, rd); return; }
  #endif
    J->base[0] = lj_opt_narrow_tobit(J, tr);
    UNUSED(rd);
  }
  
  /* Record unary bit.bnot, bit.bswap. */
  static void LJ_FASTCALL recff_bit_unary(jit_State *J, RecordFFData *rd)
  {
  #if LJ_HASFFI
    if (recff_bit64_unary(J, rd))
      return;
  #endif
    J->base[0] = emitir(IRTI(rd->data), lj_opt_narrow_tobit(J, J->base[0]), 0);
  }
  
  /* Record N-ary bit.band, bit.bor, bit.bxor. */
  static void LJ_FASTCALL recff_bit_nary(jit_State *J, RecordFFData *rd)
  {
  #if LJ_HASFFI
    if (recff_bit64_nary(J, rd))
      return;
  #endif
    {
      TRef tr = lj_opt_narrow_tobit(J, J->base[0]);
      uint32_t ot = IRTI(rd->data);
      BCReg i;
      for (i = 1; J->base[i] != 0; i++)
        tr = emitir(ot, tr, lj_opt_narrow_tobit(J, J->base[i]));
      J->base[0] = tr;
    }
  }
  
  /* Record bit shifts. */
  static void LJ_FASTCALL recff_bit_shift(jit_State *J, RecordFFData *rd)
  {
  #if LJ_HASFFI
    if (recff_bit64_shift(J, rd))
      return;
  #endif
    {
      TRef tr = lj_opt_narrow_tobit(J, J->base[0]);
      TRef tsh = lj_opt_narrow_tobit(J, J->base[1]);
      IROp op = (IROp)rd->data;
      if (!(op < IR_BROL ? LJ_TARGET_MASKSHIFT : LJ_TARGET_MASKROT) &&
  	!tref_isk(tsh))
        tsh = emitir(IRTI(IR_BAND), tsh, lj_ir_kint(J, 31));
  #ifdef LJ_TARGET_UNIFYROT
      if (op == (LJ_TARGET_UNIFYROT == 1 ? IR_BROR : IR_BROL)) {
        op = LJ_TARGET_UNIFYROT == 1 ? IR_BROL : IR_BROR;
        tsh = emitir(IRTI(IR_NEG), tsh, tsh);
      }
  #endif
      J->base[0] = emitir(IRTI(op), tr, tsh);
    }
  }
  
  static void LJ_FASTCALL recff_bit_tohex(jit_State *J, RecordFFData *rd)
  {
  #if LJ_HASFFI
    TRef hdr = recff_bufhdr(J);
    TRef tr = recff_bit64_tohex(J, rd, hdr);
    J->base[0] = emitir(IRT(IR_BUFSTR, IRT_STR), tr, hdr);
  #else
    recff_nyiu(J, rd);  /* Don't bother working around this NYI. */
  #endif
  }
  
  /* -- String library fast functions --------------------------------------- */
  
  /* Specialize to relative starting position for string. */
  static TRef recff_string_start(jit_State *J, GCstr *s, int32_t *st, TRef tr,
  			       TRef trlen, TRef tr0)
  {
    int32_t start = *st;
    if (start < 0) {
      emitir(IRTGI(IR_LT), tr, tr0);
      tr = emitir(IRTI(IR_ADD), trlen, tr);
      start = start + (int32_t)s->len;
      emitir(start < 0 ? IRTGI(IR_LT) : IRTGI(IR_GE), tr, tr0);
      if (start < 0) {
        tr = tr0;
        start = 0;
      }
    } else if (start == 0) {
      emitir(IRTGI(IR_EQ), tr, tr0);
      tr = tr0;
    } else {
      tr = emitir(IRTI(IR_ADD), tr, lj_ir_kint(J, -1));
      emitir(IRTGI(IR_GE), tr, tr0);
      start--;
    }
    *st = start;
    return tr;
  }
  
  /* Handle string.byte (rd->data = 0) and string.sub (rd->data = 1). */
  static void LJ_FASTCALL recff_string_range(jit_State *J, RecordFFData *rd)
  {
    TRef trstr = lj_ir_tostr(J, J->base[0]);
    TRef trlen = emitir(IRTI(IR_FLOAD), trstr, IRFL_STR_LEN);
    TRef tr0 = lj_ir_kint(J, 0);
    TRef trstart, trend;
    GCstr *str = argv2str(J, &rd->argv[0]);
    int32_t start, end;
    if (rd->data) {  /* string.sub(str, start [,end]) */
      start = argv2int(J, &rd->argv[1]);
      trstart = lj_opt_narrow_toint(J, J->base[1]);
      trend = J->base[2];
      if (tref_isnil(trend)) {
        trend = lj_ir_kint(J, -1);
        end = -1;
      } else {
        trend = lj_opt_narrow_toint(J, trend);
        end = argv2int(J, &rd->argv[2]);
      }
    } else {  /* string.byte(str, [,start [,end]]) */
      if (tref_isnil(J->base[1])) {
        start = 1;
        trstart = lj_ir_kint(J, 1);
      } else {
        start = argv2int(J, &rd->argv[1]);
        trstart = lj_opt_narrow_toint(J, J->base[1]);
      }
      if (J->base[1] && !tref_isnil(J->base[2])) {
        trend = lj_opt_narrow_toint(J, J->base[2]);
        end = argv2int(J, &rd->argv[2]);
      } else {
        trend = trstart;
        end = start;
      }
    }
    if (end < 0) {
      emitir(IRTGI(IR_LT), trend, tr0);
      trend = emitir(IRTI(IR_ADD), emitir(IRTI(IR_ADD), trlen, trend),
  		   lj_ir_kint(J, 1));
      end = end+(int32_t)str->len+1;
    } else if ((MSize)end <= str->len) {
      emitir(IRTGI(IR_ULE), trend, trlen);
    } else {
      emitir(IRTGI(IR_UGT), trend, trlen);
      end = (int32_t)str->len;
      trend = trlen;
    }
    trstart = recff_string_start(J, str, &start, trstart, trlen, tr0);
    if (rd->data) {  /* Return string.sub result. */
      if (end - start >= 0) {
        /* Also handle empty range here, to avoid extra traces. */
        TRef trptr, trslen = emitir(IRTI(IR_SUB), trend, trstart);
        emitir(IRTGI(IR_GE), trslen, tr0);
        trptr = emitir(IRT(IR_STRREF, IRT_PGC), trstr, trstart);
        J->base[0] = emitir(IRT(IR_SNEW, IRT_STR), trptr, trslen);
      } else {  /* Range underflow: return empty string. */
        emitir(IRTGI(IR_LT), trend, trstart);
        J->base[0] = lj_ir_kstr(J, &J2G(J)->strempty);
      }
    } else {  /* Return string.byte result(s). */
      ptrdiff_t i, len = end - start;
      if (len > 0) {
        TRef trslen = emitir(IRTI(IR_SUB), trend, trstart);
        emitir(IRTGI(IR_EQ), trslen, lj_ir_kint(J, (int32_t)len));
        if (J->baseslot + len > LJ_MAX_JSLOTS)
  	lj_trace_err_info(J, LJ_TRERR_STACKOV);
        rd->nres = len;
        for (i = 0; i < len; i++) {
  	TRef tmp = emitir(IRTI(IR_ADD), trstart, lj_ir_kint(J, (int32_t)i));
  	tmp = emitir(IRT(IR_STRREF, IRT_PGC), trstr, tmp);
  	J->base[i] = emitir(IRT(IR_XLOAD, IRT_U8), tmp, IRXLOAD_READONLY);
        }
      } else {  /* Empty range or range underflow: return no results. */
        emitir(IRTGI(IR_LE), trend, trstart);
        rd->nres = 0;
      }
    }
  }
  
  static void LJ_FASTCALL recff_string_char(jit_State *J, RecordFFData *rd)
  {
    TRef k255 = lj_ir_kint(J, 255);
    BCReg i;
    for (i = 0; J->base[i] != 0; i++) {  /* Convert char values to strings. */
      TRef tr = lj_opt_narrow_toint(J, J->base[i]);
      emitir(IRTGI(IR_ULE), tr, k255);
      J->base[i] = emitir(IRT(IR_TOSTR, IRT_STR), tr, IRTOSTR_CHAR);
    }
    if (i > 1) {  /* Concatenate the strings, if there's more than one. */
      TRef hdr = recff_bufhdr(J), tr = hdr;
      for (i = 0; J->base[i] != 0; i++)
        tr = emitir(IRT(IR_BUFPUT, IRT_PGC), tr, J->base[i]);
      J->base[0] = emitir(IRT(IR_BUFSTR, IRT_STR), tr, hdr);
    } else if (i == 0) {
      J->base[0] = lj_ir_kstr(J, &J2G(J)->strempty);
    }
    UNUSED(rd);
  }
  
  static void LJ_FASTCALL recff_string_rep(jit_State *J, RecordFFData *rd)
  {
    TRef str = lj_ir_tostr(J, J->base[0]);
    TRef rep = lj_opt_narrow_toint(J, J->base[1]);
    TRef hdr, tr, str2 = 0;
    if (!tref_isnil(J->base[2])) {
      TRef sep = lj_ir_tostr(J, J->base[2]);
      int32_t vrep = argv2int(J, &rd->argv[1]);
      emitir(IRTGI(vrep > 1 ? IR_GT : IR_LE), rep, lj_ir_kint(J, 1));
      if (vrep > 1) {
        TRef hdr2 = recff_bufhdr(J);
        TRef tr2 = emitir(IRT(IR_BUFPUT, IRT_PGC), hdr2, sep);
        tr2 = emitir(IRT(IR_BUFPUT, IRT_PGC), tr2, str);
        str2 = emitir(IRT(IR_BUFSTR, IRT_STR), tr2, hdr2);
      }
    }
    tr = hdr = recff_bufhdr(J);
    if (str2) {
      tr = emitir(IRT(IR_BUFPUT, IRT_PGC), tr, str);
      str = str2;
      rep = emitir(IRTI(IR_ADD), rep, lj_ir_kint(J, -1));
    }
    tr = lj_ir_call(J, IRCALL_lj_buf_putstr_rep, tr, str, rep);
    J->base[0] = emitir(IRT(IR_BUFSTR, IRT_STR), tr, hdr);
  }
  
  static void LJ_FASTCALL recff_string_op(jit_State *J, RecordFFData *rd)
  {
    TRef str = lj_ir_tostr(J, J->base[0]);
    TRef hdr = recff_bufhdr(J);
    TRef tr = lj_ir_call(J, rd->data, hdr, str);
    J->base[0] = emitir(IRT(IR_BUFSTR, IRT_STR), tr, hdr);
  }
  
  static int recff_emit_captures(jit_State *J, const MatchState *ms,
  				TRef tr, int off, TRef sptr)
  {
    TRef captures;
    int i;
    int capoff = offsetof(MatchState, capture[0]);
    int capsize = sizeof(ms->capture[0]);
    int initoff = offsetof(MatchState, capture[0].init) - capoff;
    int lenoff = offsetof(MatchState, capture[0].len) - capoff;
  
    if (!ms->level)
      return 0;
  
    captures = emitir(IRT(IR_ADD, IRT_P32), tr, /* IRFL_ not really applicable. */
                      lj_ir_kint(J, capoff));
    for (i = 0; i < ms->level; i++) {
      int init = i*capsize+initoff;
      if (ms->capture[i].len == CAP_POSITION) {
        J->base[off+i] =
          emitir(IRT(IR_SUB, IRT_INT),
            emitir(IRT(IR_XLOAD, IRT_P32),
              emitir(IRT(IR_ADD, IRT_P32), captures, lj_ir_kint(J, init)), 0),
            emitir(IRT(IR_SUB, IRT_P32), sptr, lj_ir_kint(J, 1))
          ); /* IR_SUB */
      } else {
        int len = i*capsize+lenoff;
        J->base[off+i] =
          emitir(IRT(IR_SNEW, IRT_STR),
            emitir(IRT(IR_XLOAD, IRT_P32),
              emitir(IRT(IR_ADD, IRT_P32), captures, lj_ir_kint(J, init)), 0),
            emitir(IRT(IR_XLOAD, IRT_INT),
              emitir(IRT(IR_ADD, IRT_P32), captures, lj_ir_kint(J, len)), 0)
          ); /* IR_SNEW */
      }
    }
    return ms->level;
  }
  
  static void LJ_FASTCALL recff_string_findmatch(jit_State *J, RecordFFData *rd)
  {
    int find = rd->data;
    TRef tr0, trstr, trsptr, trslen, trplen, trpat, trpptr;
    TRef trstart;
    int32_t start;
    GCstr *str = argv2str(J, &rd->argv[0]);
    GCstr *pat = argv2str(J, &rd->argv[1]);
    TRef kpat = 0;
    int rawfind = 0;
  
    J->needsnap = 1;
  
    tr0 = lj_ir_kint(J, 0);
    trstr = lj_ir_tostr(J, J->base[0]);
    trpat = lj_ir_tostr(J, J->base[1]);
  
    /* Optional start argument. */
    if (tref_isnil(J->base[2])) {
      trstart = lj_ir_kint(J, 1);
      start = 1;
    } else {
      trstart = lj_opt_narrow_toint(J, J->base[2]);
      start = argv2int(J, &rd->argv[2]);
    }
  
    /* Specialize on pattern only if no raw flag is specified. */
    if (!find || !(rawfind = (J->base[2] && tref_istruecond(J->base[3])))) {
      kpat = lj_ir_kstr(J, pat);
      emitir(IRTG(IR_EQ, IRT_STR), trpat, kpat);
      trpat = kpat;
    }
  
    trsptr = emitir(IRT(IR_STRREF, IRT_P32), trstr, tr0);
    trslen = emitir(IRTI(IR_FLOAD), trstr, IRFL_STR_LEN);
    trpptr = emitir(IRT(IR_STRREF, IRT_P32), trpat, tr0);
    trplen = emitir(IRTI(IR_FLOAD), trpat, IRFL_STR_LEN);
  
    if (rawfind || !lj_str_haspattern(pat)) {
      TRef tr = lj_ir_call(J, IRCALL_lj_str_find,
  		    trsptr, trpptr, trslen, trplen, trstart);
      if (lj_str_find(strdata(str), strdata(pat),
  		    str->len, pat->len, start)) {
        emitir(IRTG(IR_NE, IRT_INT), tr, tr0);
        if (!find)
          J->base[0] = kpat;
        else {
          J->base[0] = tr;
          J->base[1] = emitir(IRTI(IR_ADD), tr, emitir(IRTI(IR_SUB), trplen, 
  				lj_ir_kint(J, 1)));
          rd->nres = 2;
        }
      } else {
        emitir(IRTG(IR_EQ, IRT_INT), tr, tr0);
        J->base[0] = TREF_NIL;
      }
    } else {
      TRef tr = lj_ir_call(J, IRCALL_ljx_str_match,
  		    trsptr, trpptr, trslen, trplen, trstart);
      TRef trp0 = lj_ir_kkptr(J, NULL);
      MatchState *ms = ljx_str_match(J->L, strdata(str), strdata(pat),
  		    str->len, pat->len, start);
      if (ms) {
        int rpos = 0;
        emitir(IRTG(IR_NE, IRT_PGC), tr, trp0); /* TBD: Check if IRT_PGC is ok, was IRT_P32*/
        if (find) {
          J->base[0] = emitir(IRTI(IR_FLOAD), tr, IRFL_MS_FINDRET1);
          J->base[1] = emitir(IRTI(IR_FLOAD), tr, IRFL_MS_FINDRET2);
          rpos = 2;
        }
        rd->nres = rpos + recff_emit_captures(J, ms, tr, rpos, trsptr);
      } else {
        emitir(IRTG(IR_EQ, IRT_PGC), tr, trp0);
        J->base[0] = TREF_NIL;
      }
    }
  }
  
  static void LJ_FASTCALL recff_string_format(jit_State *J, RecordFFData *rd)
  {
    TRef trfmt = lj_ir_tostr(J, J->base[0]);
    GCstr *fmt = argv2str(J, &rd->argv[0]);
    int arg = 1;
    TRef hdr, tr;
    FormatState fs;
    SFormat sf;
    /* Specialize to the format string. */
    emitir(IRTG(IR_EQ, IRT_STR), trfmt, lj_ir_kstr(J, fmt));
    tr = hdr = recff_bufhdr(J);
    lj_strfmt_init(&fs, strdata(fmt), fmt->len);
    while ((sf = lj_strfmt_parse(&fs)) != STRFMT_EOF) {  /* Parse format. */
      TRef tra = sf == STRFMT_LIT ? 0 : J->base[arg++];
      TRef trsf = lj_ir_kint(J, (int32_t)sf);
      IRCallID id;
      switch (STRFMT_TYPE(sf)) {
      case STRFMT_LIT:
        tr = emitir(IRT(IR_BUFPUT, IRT_PGC), tr,
  		  lj_ir_kstr(J, lj_str_new(J->L, fs.str, fs.len)));
        break;
      case STRFMT_INT:
        id = IRCALL_lj_strfmt_putfnum_int;
      handle_int:
        if (!tref_isinteger(tra))
  	goto handle_num;
        if (sf == STRFMT_INT) { /* Shortcut for plain %d. */
  	tr = emitir(IRT(IR_BUFPUT, IRT_PGC), tr,
  		    emitir(IRT(IR_TOSTR, IRT_STR), tra, IRTOSTR_INT));
        } else {
  #if LJ_HASFFI
  	tra = emitir(IRT(IR_CONV, IRT_U64), tra,
  		     (IRT_INT|(IRT_U64<<5)|IRCONV_SEXT));
  	tr = lj_ir_call(J, IRCALL_lj_strfmt_putfxint, tr, trsf, tra);
  	lj_needsplit(J);
  #else
  	recff_nyiu(J, rd);  /* Don't bother working around this NYI. */
  	return;
  #endif
        }
        break;
      case STRFMT_UINT:
        id = IRCALL_lj_strfmt_putfnum_uint;
        goto handle_int;
      case STRFMT_NUM:
        id = IRCALL_lj_strfmt_putfnum;
      handle_num:
        tra = lj_ir_tonum(J, tra);
        tr = lj_ir_call(J, id, tr, trsf, tra);
        if (LJ_SOFTFP32) lj_needsplit(J);
        break;
      case STRFMT_STR:
        if (!tref_isstr(tra)) {
  	recff_nyiu(J, rd);  /* NYI: __tostring and non-string types for %s. */
  	return;
        }
        if (sf == STRFMT_STR)  /* Shortcut for plain %s. */
  	tr = emitir(IRT(IR_BUFPUT, IRT_PGC), tr, tra);
        else if ((sf & STRFMT_T_QUOTED))
  	tr = lj_ir_call(J, IRCALL_lj_strfmt_putquoted, tr, tra);
        else
  	tr = lj_ir_call(J, IRCALL_lj_strfmt_putfstr, tr, trsf, tra);
        break;
      case STRFMT_CHAR:
        tra = lj_opt_narrow_toint(J, tra);
        if (sf == STRFMT_CHAR)  /* Shortcut for plain %c. */
  	tr = emitir(IRT(IR_BUFPUT, IRT_PGC), tr,
  		    emitir(IRT(IR_TOSTR, IRT_STR), tra, IRTOSTR_CHAR));
        else
  	tr = lj_ir_call(J, IRCALL_lj_strfmt_putfchar, tr, trsf, tra);
        break;
      case STRFMT_PTR:  /* NYI */
      case STRFMT_ERR:
      default:
        recff_nyiu(J, rd);
        return;
      }
    }
    J->base[0] = emitir(IRT(IR_BUFSTR, IRT_STR), tr, hdr);
  }
  
  /* -- Table library fast functions ---------------------------------------- */
  
  static void LJ_FASTCALL recff_table_insert(jit_State *J, RecordFFData *rd)
  {
    RecordIndex ix;
    ix.tab = J->base[0];
    ix.val = J->base[1];
    rd->nres = 0;
    if (tref_istab(ix.tab) && ix.val) {
      if (!J->base[2]) {  /* Simple push: t[#t+1] = v */
        TRef trlen = emitir(IRTI(IR_ALEN), ix.tab, TREF_NIL);
        GCtab *t = tabV(&rd->argv[0]);
        ix.key = emitir(IRTI(IR_ADD), trlen, lj_ir_kint(J, 1));
        settabV(J->L, &ix.tabv, t);
        setintV(&ix.keyv, lj_tab_len(t) + 1);
        ix.idxchain = 0;
        lj_record_idx(J, &ix);  /* Set new value. */
      } else {  /* Complex case: insert in the middle. */
        recff_nyiu(J, rd);
        return;
      }
    }  /* else: Interpreter will throw. */
  }
  
  static void LJ_FASTCALL recff_table_concat(jit_State *J, RecordFFData *rd)
  {
    TRef tab = J->base[0];
    if (tref_istab(tab)) {
      TRef sep = !tref_isnil(J->base[1]) ?
  	       lj_ir_tostr(J, J->base[1]) : lj_ir_knull(J, IRT_STR);
      TRef tri = (J->base[1] && !tref_isnil(J->base[2])) ?
  	       lj_opt_narrow_toint(J, J->base[2]) : lj_ir_kint(J, 1);
      TRef tre = (J->base[1] && J->base[2] && !tref_isnil(J->base[3])) ?
  	       lj_opt_narrow_toint(J, J->base[3]) :
  	       emitir(IRTI(IR_ALEN), tab, TREF_NIL);
      TRef hdr = recff_bufhdr(J);
      TRef tr = lj_ir_call(J, IRCALL_lj_buf_puttab, hdr, tab, sep, tri, tre);
      emitir(IRTG(IR_NE, IRT_PTR), tr, lj_ir_kptr(J, NULL));
      J->base[0] = emitir(IRT(IR_BUFSTR, IRT_STR), tr, hdr);
    }  /* else: Interpreter will throw. */
    UNUSED(rd);
  }
  
  static void LJ_FASTCALL recff_table_new(jit_State *J, RecordFFData *rd)
  {
    TRef tra = lj_opt_narrow_toint(J, J->base[0]);
    TRef trh = lj_opt_narrow_toint(J, J->base[1]);
    J->base[0] = lj_ir_call(J, IRCALL_lj_tab_new_ah, tra, trh);
    UNUSED(rd);
  }
  
  static void LJ_FASTCALL recff_table_clear(jit_State *J, RecordFFData *rd)
  {
    TRef tr = J->base[0];
    if (tref_istab(tr)) {
      rd->nres = 0;
      lj_ir_call(J, IRCALL_lj_tab_clear, tr);
      J->needsnap = 1;
    }  /* else: Interpreter will throw. */
  }
  
  /* -- I/O library fast functions ------------------------------------------ */
  
  /* Get FILE* for I/O function. Any I/O error aborts recording, so there's
  ** no need to encode the alternate cases for any of the guards.
  */
  static TRef recff_io_fp(jit_State *J, TRef *udp, int32_t id)
  {
    TRef tr, ud, fp;
    if (id) {  /* io.func() */
      ud = lj_ir_ggfload(J, IRT_UDATA, GG_OFS(g.gcroot[id]));
    } else {  /* fp:method() */
      ud = J->base[0];
      if (!tref_isudata(ud))
        lj_trace_err(J, LJ_TRERR_BADTYPE);
      tr = emitir(IRT(IR_FLOAD, IRT_U8), ud, IRFL_UDATA_UDTYPE);
      emitir(IRTGI(IR_EQ), tr, lj_ir_kint(J, UDTYPE_IO_FILE));
    }
    *udp = ud;
    fp = emitir(IRT(IR_FLOAD, IRT_PTR), ud, IRFL_UDATA_FILE);
    emitir(IRTG(IR_NE, IRT_PTR), fp, lj_ir_knull(J, IRT_PTR));
    return fp;
  }
  
  static void LJ_FASTCALL recff_io_write(jit_State *J, RecordFFData *rd)
  {
    TRef ud, fp = recff_io_fp(J, &ud, rd->data);
    TRef zero = lj_ir_kint(J, 0);
    TRef one = lj_ir_kint(J, 1);
    ptrdiff_t i = rd->data == 0 ? 1 : 0;
    for (; J->base[i]; i++) {
      TRef str = lj_ir_tostr(J, J->base[i]);
      TRef buf = emitir(IRT(IR_STRREF, IRT_PGC), str, zero);
      TRef len = emitir(IRTI(IR_FLOAD), str, IRFL_STR_LEN);
      if (tref_isk(len) && IR(tref_ref(len))->i == 1) {
        IRIns *irs = IR(tref_ref(str));
        TRef tr = (irs->o == IR_TOSTR && irs->op2 == IRTOSTR_CHAR) ?
  		irs->op1 :
  		emitir(IRT(IR_XLOAD, IRT_U8), buf, IRXLOAD_READONLY);
        tr = lj_ir_call(J, IRCALL_fputc, tr, fp);
        if (results_wanted(J) != 0)  /* Check result only if not ignored. */
  	emitir(IRTGI(IR_NE), tr, lj_ir_kint(J, -1));
      } else {
        TRef tr = lj_ir_call(J, IRCALL_fwrite, buf, one, len, fp);
        if (results_wanted(J) != 0)  /* Check result only if not ignored. */
  	emitir(IRTGI(IR_EQ), tr, len);
      }
    }
    J->base[0] = ud;
  }
  
  static void LJ_FASTCALL recff_io_flush(jit_State *J, RecordFFData *rd)
  {
    TRef ud, fp = recff_io_fp(J, &ud, rd->data);
    TRef tr = lj_ir_call(J, IRCALL_fflush, fp);
    if (results_wanted(J) != 0)  /* Check result only if not ignored. */
      emitir(IRTGI(IR_EQ), tr, lj_ir_kint(J, 0));
    J->base[0] = TREF_TRUE;
  }
  
  /* -- Debug library fast functions ---------------------------------------- */
  
  static void LJ_FASTCALL recff_debug_getmetatable(jit_State *J, RecordFFData *rd)
  {
    GCtab *mt;
    TRef mtref;
    TRef tr = J->base[0];
    if (tref_istab(tr)) {
      mt = tabref(tabV(&rd->argv[0])->metatable);
      mtref = emitir(IRT(IR_FLOAD, IRT_TAB), tr, IRFL_TAB_META);
    } else if (tref_isudata(tr)) {
      mt = tabref(udataV(&rd->argv[0])->metatable);
      mtref = emitir(IRT(IR_FLOAD, IRT_TAB), tr, IRFL_UDATA_META);
    } else {
      mt = tabref(basemt_obj(J2G(J), &rd->argv[0]));
      J->base[0] = mt ? lj_ir_ktab(J, mt) : TREF_NIL;
      return;
    }
    emitir(IRTG(mt ? IR_NE : IR_EQ, IRT_TAB), mtref, lj_ir_knull(J, IRT_TAB));
    J->base[0] = mt ? mtref : TREF_NIL;
  }
  
  static void LJ_FASTCALL recff_debug_setmetatable(jit_State *J, RecordFFData *rd)
  {
    TRef tr = J->base[0];
    TRef mt = J->base[1];
    /* Note: lua_setmetatable for base_mt provides no benefit. */
    if (tref_istab(tr) && (tref_istab(mt) || (mt && tref_isnil(mt)))) {
      TRef fref, mtref;
      fref = emitir(IRT(IR_FREF, IRT_P32), tr, IRFL_TAB_META);
      mtref = tref_isnil(mt) ? lj_ir_knull(J, IRT_TAB) : mt;
      emitir(IRT(IR_FSTORE, IRT_TAB), fref, mtref);
      if (!tref_isnil(mt)) {
        emitir(IRT(IR_TBAR, IRT_TAB), tr, 0);
        setmetatable_gc_guard(J, rd);
      }
      J->base[0] = tr;
      J->needsnap = 1;
    } else {
      recff_nyiu(J, rd);
    }
  }
  
  
  /* -- Record calls to fast functions -------------------------------------- */
  
  #include "lj_recdef.h"
  
  static uint32_t recdef_lookup(GCfunc *fn)
  {
    if (fn->c.ffid < sizeof(recff_idmap)/sizeof(recff_idmap[0]))
      return recff_idmap[fn->c.ffid];
    else
      return 0;
  }
  
  /* Record entry to a fast function or C function. */
  void lj_ffrecord_func(jit_State *J)
  {
    RecordFFData rd;
    uint32_t m = recdef_lookup(J->fn);
    rd.data = m & 0xff;
    rd.nres = 1;  /* Default is one result. */
    rd.argv = J->L->base;
    J->base[J->maxslot] = 0;  /* Mark end of arguments. */
    (recff_func[m >> 8])(J, &rd);  /* Call recff_* handler. */
    if (rd.nres >= 0) {
      if (J->postproc == LJ_POST_NONE) J->postproc = LJ_POST_FFRETRY;
      lj_record_ret(J, 0, rd.nres);
    }
  }
  
  #undef IR
  #undef emitir
  
  #endif
  