src/lib_jit.c

   1 /*
   2 ** JIT library.
   3 ** Copyright (C) 2005-2025 Mike Pall. See Copyright Notice in luajit.h
   4 */
   5
   6 #define lib_jit_c
   7 #define LUA_LIB
   8
   9 #include "lua.h"
  10 #include "lauxlib.h"
  11 #include "lualib.h"
  12
  13 #include "lj_obj.h"
  14 #include "lj_gc.h"
  15 #include "lj_err.h"
  16 #include "lj_debug.h"
  17 #include "lj_str.h"
  18 #include "lj_tab.h"
  19 #include "lj_state.h"
  20 #include "lj_bc.h"
  21 #if LJ_HASFFI
  22 #include "lj_ctype.h"
  23 #endif
  24 #if LJ_HASJIT
  25 #include "lj_ir.h"
  26 #include "lj_jit.h"
  27 #include "lj_ircall.h"
  28 #include "lj_iropt.h"
  29 #include "lj_target.h"
  30 #endif
  31 #include "lj_trace.h"
  32 #include "lj_dispatch.h"
  33 #include "lj_vm.h"
  34 #include "lj_vmevent.h"
  35 #include "lj_lib.h"
  36
  37 #include "luajit.h"
  38
  39 /* -- jit.* functions ----------------------------------------------------- */
  40
  41 #define LJLIB_MODULE_jit
  42
  43 static int setjitmode(lua_State *L, int mode)
  44 {
  45   int idx = 0;
  46   if (L->base == L->top || tvisnil(L->base)) {  /* jit.on/off/flush([nil]) */
  47     mode |= LUAJIT_MODE_ENGINE;
  48   } else {
  49     /* jit.on/off/flush(func|proto, nil|true|false) */
  50     if (tvisfunc(L->base) || tvisproto(L->base))
  51       idx = 1;
  52     else if (!tvistrue(L->base))  /* jit.on/off/flush(true, nil|true|false) */
  53       goto err;
  54     if (L->base+1 < L->top && tvisbool(L->base+1))
  55       mode |= boolV(L->base+1) ? LUAJIT_MODE_ALLFUNC : LUAJIT_MODE_ALLSUBFUNC;
  56     else
  57       mode |= LUAJIT_MODE_FUNC;
  58   }
  59   if (luaJIT_setmode(L, idx, mode) != 1) {
  60     if ((mode & LUAJIT_MODE_MASK) == LUAJIT_MODE_ENGINE)
  61       lj_err_caller(L, LJ_ERR_NOJIT);
  62   err:
  63     lj_err_argt(L, 1, LUA_TFUNCTION);
  64   }
  65   return 0;
  66 }
  67
  68 LJLIB_CF(jit_on)
  69 {
  70   return setjitmode(L, LUAJIT_MODE_ON);
  71 }
  72
  73 LJLIB_CF(jit_off)
  74 {
  75   return setjitmode(L, LUAJIT_MODE_OFF);
  76 }
  77
  78 LJLIB_CF(jit_flush)
  79 {
  80 #if LJ_HASJIT
  81   if (L->base < L->top && tvisnumber(L->base)) {
  82     int traceno = lj_lib_checkint(L, 1);
  83     luaJIT_setmode(L, traceno, LUAJIT_MODE_FLUSH|LUAJIT_MODE_TRACE);
  84     return 0;
  85   }
  86 #endif
  87   return setjitmode(L, LUAJIT_MODE_FLUSH);
  88 }
  89
  90 #if LJ_HASJIT
  91 /* Push a string for every flag bit that is set. */
  92 static void flagbits_to_strings(lua_State *L, uint32_t flags, uint32_t base,
  93                                 const char *str)
  94 {
  95   for (; *str; base <<= 1, str += 1+*str)
  96     if (flags & base)
  97       setstrV(L, L->top++, lj_str_new(L, str+1, *(uint8_t *)str));
  98 }
  99 #endif
 100
 101 LJLIB_CF(jit_status)
 102 {
 103 #if LJ_HASJIT
 104   jit_State *J = L2J(L);
 105   L->top = L->base;
 106   setboolV(L->top++, (J->flags & JIT_F_ON) ? 1 : 0);
 107   flagbits_to_strings(L, J->flags, JIT_F_CPU, JIT_F_CPUSTRING);
 108   flagbits_to_strings(L, J->flags, JIT_F_OPT, JIT_F_OPTSTRING);
 109   return (int)(L->top - L->base);
 110 #else
 111   setboolV(L->top++, 0);
 112   return 1;
 113 #endif
 114 }
 115
 116 LJLIB_CF(jit_security)
 117 {
 118   int idx = lj_lib_checkopt(L, 1, -1, LJ_SECURITY_MODESTRING);
 119   setintV(L->top++, ((LJ_SECURITY_MODE >> (2*idx)) & 3));
 120   return 1;
 121 }
 122
 123 LJLIB_CF(jit_attach)
 124 {
 125 #ifdef LUAJIT_DISABLE_VMEVENT
 126   luaL_error(L, "vmevent API disabled");
 127 #else
 128   GCfunc *fn = lj_lib_checkfunc(L, 1);
 129   GCstr *s = lj_lib_optstr(L, 2);
 130   luaL_findtable(L, LUA_REGISTRYINDEX, LJ_VMEVENTS_REGKEY, LJ_VMEVENTS_HSIZE);
 131   if (s) {  /* Attach to given event. */
 132     const uint8_t *p = (const uint8_t *)strdata(s);
 133     uint32_t h = s->len;
 134     while (*p) h = h ^ (lj_rol(h, 6) + *p++);
 135     lua_pushvalue(L, 1);
 136     lua_rawseti(L, -2, VMEVENT_HASHIDX(h));
 137     G(L)->vmevmask = VMEVENT_NOCACHE;  /* Invalidate cache. */
 138   } else {  /* Detach if no event given. */
 139     setnilV(L->top++);
 140     while (lua_next(L, -2)) {
 141       L->top--;
 142       if (tvisfunc(L->top) && funcV(L->top) == fn) {
 143         setnilV(lj_tab_set(L, tabV(L->top-2), L->top-1));
 144       }
 145     }
 146   }
 147 #endif
 148   return 0;
 149 }
 150
 151 LJLIB_PUSH(top-5) LJLIB_SET(os)
 152 LJLIB_PUSH(top-4) LJLIB_SET(arch)
 153 LJLIB_PUSH(top-3) LJLIB_SET(version_num)
 154 LJLIB_PUSH(top-2) LJLIB_SET(version)
 155
 156 #include "lj_libdef.h"
 157
 158 /* -- jit.util.* functions ------------------------------------------------ */
 159
 160 #define LJLIB_MODULE_jit_util
 161
 162 /* -- Reflection API for Lua functions ------------------------------------ */
 163
 164 static void setintfield(lua_State *L, GCtab *t, const char *name, int32_t val)
 165 {
 166   setintV(lj_tab_setstr(L, t, lj_str_newz(L, name)), val);
 167 }
 168
 169 /* local info = jit.util.funcinfo(func [,pc]) */
 170 LJLIB_CF(jit_util_funcinfo)
 171 {
 172   GCproto *pt = lj_lib_checkLproto(L, 1, 1);
 173   if (pt) {
 174     BCPos pc = (BCPos)lj_lib_optint(L, 2, 0);
 175     GCtab *t;
 176     lua_createtable(L, 0, 16);  /* Increment hash size if fields are added. */
 177     t = tabV(L->top-1);
 178     setintfield(L, t, "linedefined", pt->firstline);
 179     setintfield(L, t, "lastlinedefined", pt->firstline + pt->numline);
 180     setintfield(L, t, "stackslots", pt->framesize);
 181     setintfield(L, t, "params", pt->numparams);
 182     setintfield(L, t, "bytecodes", (int32_t)pt->sizebc);
 183     setintfield(L, t, "gcconsts", (int32_t)pt->sizekgc);
 184     setintfield(L, t, "nconsts", (int32_t)pt->sizekn);
 185     setintfield(L, t, "upvalues", (int32_t)pt->sizeuv);
 186     if (pc < pt->sizebc)
 187       setintfield(L, t, "currentline", lj_debug_line(pt, pc));
 188     lua_pushboolean(L, (pt->flags & PROTO_VARARG));
 189     lua_setfield(L, -2, "isvararg");
 190     lua_pushboolean(L, (pt->flags & PROTO_CHILD));
 191     lua_setfield(L, -2, "children");
 192     setstrV(L, L->top++, proto_chunkname(pt));
 193     lua_setfield(L, -2, "source");
 194     lj_debug_pushloc(L, pt, pc);
 195     lua_setfield(L, -2, "loc");
 196     setprotoV(L, lj_tab_setstr(L, t, lj_str_newlit(L, "proto")), pt);
 197   } else {
 198     GCfunc *fn = funcV(L->base);
 199     GCtab *t;
 200     lua_createtable(L, 0, 4);  /* Increment hash size if fields are added. */
 201     t = tabV(L->top-1);
 202     if (!iscfunc(fn))
 203       setintfield(L, t, "ffid", fn->c.ffid);
 204     setintptrV(lj_tab_setstr(L, t, lj_str_newlit(L, "addr")),
 205                (intptr_t)(void *)fn->c.f);
 206     setintfield(L, t, "upvalues", fn->c.nupvalues);
 207   }
 208   return 1;
 209 }
 210
 211 /* local ins, m = jit.util.funcbc(func, pc) */
 212 LJLIB_CF(jit_util_funcbc)
 213 {
 214   GCproto *pt = lj_lib_checkLproto(L, 1, 0);
 215   BCPos pc = (BCPos)lj_lib_checkint(L, 2);
 216   if (pc < pt->sizebc) {
 217     BCIns ins = proto_bc(pt)[pc];
 218     BCOp op = bc_op(ins);
 219     lj_assertL(op < BC__MAX, "bad bytecode op %d", op);
 220     setintV(L->top, ins);
 221     setintV(L->top+1, lj_bc_mode[op]);
 222     L->top += 2;
 223     return 2;
 224   }
 225   return 0;
 226 }
 227
 228 /* local k = jit.util.funck(func, idx) */
 229 LJLIB_CF(jit_util_funck)
 230 {
 231   GCproto *pt = lj_lib_checkLproto(L, 1, 0);
 232   ptrdiff_t idx = (ptrdiff_t)lj_lib_checkint(L, 2);
 233   if (idx >= 0) {
 234     if (idx < (ptrdiff_t)pt->sizekn) {
 235       copyTV(L, L->top-1, proto_knumtv(pt, idx));
 236       return 1;
 237     }
 238   } else {
 239     if (~idx < (ptrdiff_t)pt->sizekgc) {
 240       GCobj *gc = proto_kgc(pt, idx);
 241       setgcV(L, L->top-1, gc, ~gc->gch.gct);
 242       return 1;
 243     }
 244   }
 245   return 0;
 246 }
 247
 248 /* local name = jit.util.funcuvname(func, idx) */
 249 LJLIB_CF(jit_util_funcuvname)
 250 {
 251   GCproto *pt = lj_lib_checkLproto(L, 1, 0);
 252   uint32_t idx = (uint32_t)lj_lib_checkint(L, 2);
 253   if (idx < pt->sizeuv) {
 254     setstrV(L, L->top-1, lj_str_newz(L, lj_debug_uvname(pt, idx)));
 255     return 1;
 256   }
 257   return 0;
 258 }
 259
 260 /* -- Reflection API for traces ------------------------------------------- */
 261
 262 #if LJ_HASJIT
 263
 264 /* Check trace argument. Must not throw for non-existent trace numbers. */
 265 static GCtrace *jit_checktrace(lua_State *L)
 266 {
 267   TraceNo tr = (TraceNo)lj_lib_checkint(L, 1);
 268   jit_State *J = L2J(L);
 269   if (tr > 0 && tr < J->sizetrace)
 270     return traceref(J, tr);
 271   return NULL;
 272 }
 273
 274 /* Names of link types. ORDER LJ_TRLINK */
 275 static const char *const jit_trlinkname[] = {
 276   "none", "root", "loop", "tail-recursion", "up-recursion", "down-recursion",
 277   "interpreter", "return", "stitch"
 278 };
 279
 280 /* local info = jit.util.traceinfo(tr) */
 281 LJLIB_CF(jit_util_traceinfo)
 282 {
 283   GCtrace *T = jit_checktrace(L);
 284   if (T) {
 285     GCtab *t;
 286     lua_createtable(L, 0, 8);  /* Increment hash size if fields are added. */
 287     t = tabV(L->top-1);
 288     setintfield(L, t, "nins", (int32_t)T->nins - REF_BIAS - 1);
 289     setintfield(L, t, "nk", REF_BIAS - (int32_t)T->nk);
 290     setintfield(L, t, "link", T->link);
 291     setintfield(L, t, "nexit", T->nsnap);
 292     setstrV(L, L->top++, lj_str_newz(L, jit_trlinkname[T->linktype]));
 293     lua_setfield(L, -2, "linktype");
 294     /* There are many more fields. Add them only when needed. */
 295     return 1;
 296   }
 297   return 0;
 298 }
 299
 300 /* local m, ot, op1, op2, prev = jit.util.traceir(tr, idx) */
 301 LJLIB_CF(jit_util_traceir)
 302 {
 303   GCtrace *T = jit_checktrace(L);
 304   IRRef ref = (IRRef)lj_lib_checkint(L, 2) + REF_BIAS;
 305   if (T && ref >= REF_BIAS && ref < T->nins) {
 306     IRIns *ir = &T->ir[ref];
 307     int32_t m = lj_ir_mode[ir->o];
 308     setintV(L->top-2, m);
 309     setintV(L->top-1, ir->ot);
 310     setintV(L->top++, (int32_t)ir->op1 - (irm_op1(m)==IRMref ? REF_BIAS : 0));
 311     setintV(L->top++, (int32_t)ir->op2 - (irm_op2(m)==IRMref ? REF_BIAS : 0));
 312     setintV(L->top++, ir->prev);
 313     return 5;
 314   }
 315   return 0;
 316 }
 317
 318 /* local k, t [, slot] = jit.util.tracek(tr, idx) */
 319 LJLIB_CF(jit_util_tracek)
 320 {
 321   GCtrace *T = jit_checktrace(L);
 322   IRRef ref = (IRRef)lj_lib_checkint(L, 2) + REF_BIAS;
 323   if (T && ref >= T->nk && ref < REF_BIAS) {
 324     IRIns *ir = &T->ir[ref];
 325     int32_t slot = -1;
 326     if (ir->o == IR_KSLOT) {
 327       slot = ir->op2;
 328       ir = &T->ir[ir->op1];
 329     }
 330 #if LJ_HASFFI
 331     if (ir->o == IR_KINT64) ctype_loadffi(L);
 332 #endif
 333     lj_ir_kvalue(L, L->top-2, ir);
 334     setintV(L->top-1, (int32_t)irt_type(ir->t));
 335     if (slot == -1)
 336       return 2;
 337     setintV(L->top++, slot);
 338     return 3;
 339   }
 340   return 0;
 341 }
 342
 343 /* local snap = jit.util.tracesnap(tr, sn) */
 344 LJLIB_CF(jit_util_tracesnap)
 345 {
 346   GCtrace *T = jit_checktrace(L);
 347   SnapNo sn = (SnapNo)lj_lib_checkint(L, 2);
 348   if (T && sn < T->nsnap) {
 349     SnapShot *snap = &T->snap[sn];
 350     SnapEntry *map = &T->snapmap[snap->mapofs];
 351     MSize n, nent = snap->nent;
 352     GCtab *t;
 353     lua_createtable(L, nent+2, 0);
 354     t = tabV(L->top-1);
 355     setintV(lj_tab_setint(L, t, 0), (int32_t)snap->ref - REF_BIAS);
 356     setintV(lj_tab_setint(L, t, 1), (int32_t)snap->nslots);
 357     for (n = 0; n < nent; n++)
 358       setintV(lj_tab_setint(L, t, (int32_t)(n+2)), (int32_t)map[n]);
 359     setintV(lj_tab_setint(L, t, (int32_t)(nent+2)), (int32_t)SNAP(255, 0, 0));
 360     return 1;
 361   }
 362   return 0;
 363 }
 364
 365 /* local mcode, addr, loop = jit.util.tracemc(tr) */
 366 LJLIB_CF(jit_util_tracemc)
 367 {
 368   GCtrace *T = jit_checktrace(L);
 369   if (T && T->mcode != NULL) {
 370     setstrV(L, L->top-1, lj_str_new(L, (const char *)T->mcode, T->szmcode));
 371     setintptrV(L->top++, (intptr_t)(void *)T->mcode);
 372     setintV(L->top++, T->mcloop);
 373     return 3;
 374   }
 375   return 0;
 376 }
 377
 378 /* local addr = jit.util.traceexitstub([tr,] exitno) */
 379 LJLIB_CF(jit_util_traceexitstub)
 380 {
 381 #ifdef EXITSTUBS_PER_GROUP
 382   ExitNo exitno = (ExitNo)lj_lib_checkint(L, 1);
 383   jit_State *J = L2J(L);
 384   if (exitno < EXITSTUBS_PER_GROUP*LJ_MAX_EXITSTUBGR) {
 385     setintptrV(L->top-1, (intptr_t)(void *)exitstub_addr(J, exitno));
 386     return 1;
 387   }
 388 #else
 389   if (L->top > L->base+1) {  /* Don't throw for one-argument variant. */
 390     GCtrace *T = jit_checktrace(L);
 391     ExitNo exitno = (ExitNo)lj_lib_checkint(L, 2);
 392     ExitNo maxexit = T->root ? T->nsnap+1 : T->nsnap;
 393     if (T && T->mcode != NULL && exitno < maxexit) {
 394       setintptrV(L->top-1, (intptr_t)(void *)exitstub_trace_addr(T, exitno));
 395       return 1;
 396     }
 397   }
 398 #endif
 399   return 0;
 400 }
 401
 402 /* local addr = jit.util.ircalladdr(idx) */
 403 LJLIB_CF(jit_util_ircalladdr)
 404 {
 405   uint32_t idx = (uint32_t)lj_lib_checkint(L, 1);
 406   if (idx < IRCALL__MAX) {
 407     ASMFunction func = lj_ir_callinfo[idx].func;
 408     setintptrV(L->top-1, (intptr_t)(void *)lj_ptr_strip(func));
 409     return 1;
 410   }
 411   return 0;
 412 }
 413
 414 #endif
 415
 416 #include "lj_libdef.h"
 417
 418 static int luaopen_jit_util(lua_State *L)
 419 {
 420   LJ_LIB_REG(L, NULL, jit_util);
 421   return 1;
 422 }
 423
 424 /* -- jit.opt module ------------------------------------------------------ */
 425
 426 #if LJ_HASJIT
 427
 428 #define LJLIB_MODULE_jit_opt
 429
 430 /* Parse optimization level. */
 431 static int jitopt_level(jit_State *J, const char *str)
 432 {
 433   if (str[0] >= '0' && str[0] <= '9' && str[1] == '\0') {
 434     uint32_t flags;
 435     if (str[0] == '0') flags = JIT_F_OPT_0;
 436     else if (str[0] == '1') flags = JIT_F_OPT_1;
 437     else if (str[0] == '2') flags = JIT_F_OPT_2;
 438     else flags = JIT_F_OPT_3;
 439     J->flags = (J->flags & ~JIT_F_OPT_MASK) | flags;
 440     return 1;  /* Ok. */
 441   }
 442   return 0;  /* No match. */
 443 }
 444
 445 /* Parse optimization flag. */
 446 static int jitopt_flag(jit_State *J, const char *str)
 447 {
 448   const char *lst = JIT_F_OPTSTRING;
 449   uint32_t opt;
 450   int set = 1;
 451   if (str[0] == '+') {
 452     str++;
 453   } else if (str[0] == '-') {
 454     str++;
 455     set = 0;
 456   } else if (str[0] == 'n' && str[1] == 'o') {
 457     str += str[2] == '-' ? 3 : 2;
 458     set = 0;
 459   }
 460   for (opt = JIT_F_OPT; ; opt <<= 1) {
 461     size_t len = *(const uint8_t *)lst;
 462     if (len == 0)
 463       break;
 464     if (strncmp(str, lst+1, len) == 0 && str[len] == '\0') {
 465       if (set) J->flags |= opt; else J->flags &= ~opt;
 466       return 1;  /* Ok. */
 467     }
 468     lst += 1+len;
 469   }
 470   return 0;  /* No match. */
 471 }
 472
 473 /* Parse optimization parameter. */
 474 static int jitopt_param(jit_State *J, const char *str)
 475 {
 476   const char *lst = JIT_P_STRING;
 477   int i;
 478   for (i = 0; i < JIT_P__MAX; i++) {
 479     size_t len = *(const uint8_t *)lst;
 480     lj_assertJ(len != 0, "bad JIT_P_STRING");
 481     if (strncmp(str, lst+1, len) == 0 && str[len] == '=') {
 482       int32_t n = 0;
 483       const char *p = &str[len+1];
 484       while (*p >= '0' && *p <= '9')
 485         n = n*10 + (*p++ - '0');
 486       if (*p) return 0;  /* Malformed number. */
 487       J->param[i] = n;
 488       if (i == JIT_P_hotloop)
 489         lj_dispatch_init_hotcount(J2G(J));
 490       return 1;  /* Ok. */
 491     }
 492     lst += 1+len;
 493   }
 494   return 0;  /* No match. */
 495 }
 496
 497 /* jit.opt.start(flags...) */
 498 LJLIB_CF(jit_opt_start)
 499 {
 500   jit_State *J = L2J(L);
 501   int nargs = (int)(L->top - L->base);
 502   if (nargs == 0) {
 503     J->flags = (J->flags & ~JIT_F_OPT_MASK) | JIT_F_OPT_DEFAULT;
 504   } else {
 505     int i;
 506     for (i = 1; i <= nargs; i++) {
 507       const char *str = strdata(lj_lib_checkstr(L, i));
 508       if (!jitopt_level(J, str) &&
 509           !jitopt_flag(J, str) &&
 510           !jitopt_param(J, str))
 511         lj_err_callerv(L, LJ_ERR_JITOPT, str);
 512     }
 513   }
 514   return 0;
 515 }
 516
 517 #include "lj_libdef.h"
 518
 519 #endif
 520
 521 /* -- jit.profile module -------------------------------------------------- */
 522
 523 #if LJ_HASPROFILE
 524
 525 #define LJLIB_MODULE_jit_profile
 526
 527 /* Not loaded by default, use: local profile = require("jit.profile") */
 528
 529 #define KEY_PROFILE_THREAD      (U64x(80000000,00000000)|'t')
 530 #define KEY_PROFILE_FUNC        (U64x(80000000,00000000)|'f')
 531
 532 static void jit_profile_callback(lua_State *L2, lua_State *L, int samples,
 533                                  int vmstate)
 534 {
 535   TValue key;
 536   cTValue *tv;
 537   key.u64 = KEY_PROFILE_FUNC;
 538   tv = lj_tab_get(L, tabV(registry(L)), &key);
 539   if (tvisfunc(tv)) {
 540     char vmst = (char)vmstate;
 541     int status;
 542     setfuncV(L2, L2->top++, funcV(tv));
 543     setthreadV(L2, L2->top++, L);
 544     setintV(L2->top++, samples);
 545     setstrV(L2, L2->top++, lj_str_new(L2, &vmst, 1));
 546     status = lua_pcall(L2, 3, 0, 0);  /* callback(thread, samples, vmstate) */
 547     if (status) {
 548       if (G(L2)->panic) G(L2)->panic(L2);
 549       exit(EXIT_FAILURE);
 550     }
 551     lj_trace_abort(G(L2));
 552   }
 553 }
 554
 555 /* profile.start(mode, cb) */
 556 LJLIB_CF(jit_profile_start)
 557 {
 558   GCtab *registry = tabV(registry(L));
 559   GCstr *mode = lj_lib_optstr(L, 1);
 560   GCfunc *func = lj_lib_checkfunc(L, 2);
 561   lua_State *L2 = lua_newthread(L);  /* Thread that runs profiler callback. */
 562   TValue key;
 563   /* Anchor thread and function in registry. */
 564   key.u64 = KEY_PROFILE_THREAD;
 565   setthreadV(L, lj_tab_set(L, registry, &key), L2);
 566   key.u64 = KEY_PROFILE_FUNC;
 567   setfuncV(L, lj_tab_set(L, registry, &key), func);
 568   lj_gc_anybarriert(L, registry);
 569   luaJIT_profile_start(L, mode ? strdata(mode) : "",
 570                        (luaJIT_profile_callback)jit_profile_callback, L2);
 571   return 0;
 572 }
 573
 574 /* profile.stop() */
 575 LJLIB_CF(jit_profile_stop)
 576 {
 577   GCtab *registry;
 578   TValue key;
 579   luaJIT_profile_stop(L);
 580   registry = tabV(registry(L));
 581   key.u64 = KEY_PROFILE_THREAD;
 582   setnilV(lj_tab_set(L, registry, &key));
 583   key.u64 = KEY_PROFILE_FUNC;
 584   setnilV(lj_tab_set(L, registry, &key));
 585   lj_gc_anybarriert(L, registry);
 586   return 0;
 587 }
 588
 589 /* dump = profile.dumpstack([thread,] fmt, depth) */
 590 LJLIB_CF(jit_profile_dumpstack)
 591 {
 592   lua_State *L2 = L;
 593   int arg = 0;
 594   size_t len;
 595   int depth;
 596   GCstr *fmt;
 597   const char *p;
 598   if (L->top > L->base && tvisthread(L->base)) {
 599     L2 = threadV(L->base);
 600     arg = 1;
 601   }
 602   fmt = lj_lib_checkstr(L, arg+1);
 603   depth = lj_lib_checkint(L, arg+2);
 604   p = luaJIT_profile_dumpstack(L2, strdata(fmt), depth, &len);
 605   lua_pushlstring(L, p, len);
 606   return 1;
 607 }
 608
 609 #include "lj_libdef.h"
 610
 611 static int luaopen_jit_profile(lua_State *L)
 612 {
 613   LJ_LIB_REG(L, NULL, jit_profile);
 614   return 1;
 615 }
 616
 617 #endif
 618
 619 /* -- JIT compiler initialization ----------------------------------------- */
 620
 621 #if LJ_HASJIT
 622 /* Default values for JIT parameters. */
 623 static const int32_t jit_param_default[JIT_P__MAX+1] = {
 624 #define JIT_PARAMINIT(len, name, value) (value),
 625 JIT_PARAMDEF(JIT_PARAMINIT)
 626 #undef JIT_PARAMINIT
 627   0
 628 };
 629
 630 #if LJ_TARGET_ARM && LJ_TARGET_LINUX
 631 #include <sys/utsname.h>
 632 #endif
 633
 634 /* Arch-dependent CPU feature detection. */
 635 static uint32_t jit_cpudetect(void)
 636 {
 637   uint32_t flags = 0;
 638 #if LJ_TARGET_X86ORX64
 639
 640   uint32_t vendor[4];
 641   uint32_t features[4];
 642   if (lj_vm_cpuid(0, vendor) && lj_vm_cpuid(1, features)) {
 643     flags |= ((features[2] >> 0)&1) * JIT_F_SSE3;
 644     flags |= ((features[2] >> 19)&1) * JIT_F_SSE4_1;
 645     if (vendor[0] >= 7) {
 646       uint32_t xfeatures[4];
 647       lj_vm_cpuid(7, xfeatures);
 648       flags |= ((xfeatures[1] >> 8)&1) * JIT_F_BMI2;
 649     }
 650   }
 651   /* Don't bother checking for SSE2 -- the VM will crash before getting here. */
 652
 653 #elif LJ_TARGET_ARM
 654
 655   int ver = LJ_ARCH_VERSION;  /* Compile-time ARM CPU detection. */
 656 #if LJ_TARGET_LINUX
 657   if (ver < 70) {  /* Runtime ARM CPU detection. */
 658     struct utsname ut;
 659     uname(&ut);
 660     if (strncmp(ut.machine, "armv", 4) == 0) {
 661       if (ut.machine[4] >= '8') ver = 80;
 662       else if (ut.machine[4] == '7') ver = 70;
 663       else if (ut.machine[4] == '6') ver = 60;
 664     }
 665   }
 666 #endif
 667   flags |= ver >= 70 ? JIT_F_ARMV7 :
 668            ver >= 61 ? JIT_F_ARMV6T2_ :
 669            ver >= 60 ? JIT_F_ARMV6_ : 0;
 670   flags |= LJ_ARCH_HASFPU == 0 ? 0 : ver >= 70 ? JIT_F_VFPV3 : JIT_F_VFPV2;
 671
 672 #elif LJ_TARGET_ARM64
 673
 674   /* No optional CPU features to detect (for now). */
 675
 676 #elif LJ_TARGET_PPC
 677
 678 #if LJ_ARCH_SQRT
 679   flags |= JIT_F_SQRT;
 680 #endif
 681 #if LJ_ARCH_ROUND
 682   flags |= JIT_F_ROUND;
 683 #endif
 684
 685 #elif LJ_TARGET_MIPS
 686
 687   /* Compile-time MIPS CPU detection. */
 688 #if LJ_ARCH_VERSION >= 20
 689   flags |= JIT_F_MIPSXXR2;
 690 #endif
 691   /* Runtime MIPS CPU detection. */
 692 #if defined(__GNUC__)
 693   if (!(flags & JIT_F_MIPSXXR2)) {
 694     int x;
 695 #ifdef __mips16
 696     x = 0;  /* Runtime detection is difficult. Ensure optimal -march flags. */
 697 #else
 698     /* On MIPS32R1 rotr is treated as srl. rotr r2,r2,1 -> srl r2,r2,1. */
 699     __asm__("li $2, 1\n\t.long 0x00221042\n\tmove %0, $2" : "=r"(x) : : "$2");
 700 #endif
 701     if (x) flags |= JIT_F_MIPSXXR2;  /* Either 0x80000000 (R2) or 0 (R1). */
 702   }
 703 #endif
 704
 705 #else
 706 #error "Missing CPU detection for this architecture"
 707 #endif
 708   return flags;
 709 }
 710
 711 /* Initialize JIT compiler. */
 712 static void jit_init(lua_State *L)
 713 {
 714   jit_State *J = L2J(L);
 715   J->flags = jit_cpudetect() | JIT_F_ON | JIT_F_OPT_DEFAULT;
 716   memcpy(J->param, jit_param_default, sizeof(J->param));
 717   lj_dispatch_update(G(L));
 718 }
 719 #endif
 720
 721 LUALIB_API int luaopen_jit(lua_State *L)
 722 {
 723 #if LJ_HASJIT
 724   jit_init(L);
 725 #endif
 726   lua_pushliteral(L, LJ_OS_NAME);
 727   lua_pushliteral(L, LJ_ARCH_NAME);
 728   lua_pushinteger(L, LUAJIT_VERSION_NUM);  /* Deprecated. */
 729   lua_pushliteral(L, LUAJIT_VERSION);
 730   LJ_LIB_REG(L, LUA_JITLIBNAME, jit);
 731 #if LJ_HASPROFILE
 732   lj_lib_prereg(L, LUA_JITLIBNAME ".profile", luaopen_jit_profile,
 733                 tabref(L->env));
 734 #endif
 735 #ifndef LUAJIT_DISABLE_JITUTIL
 736   lj_lib_prereg(L, LUA_JITLIBNAME ".util", luaopen_jit_util, tabref(L->env));
 737 #endif
 738 #if LJ_HASJIT
 739   LJ_LIB_REG(L, "jit.opt", jit_opt);
 740 #endif
 741   L->top -= 2;
 742   return 1;
 743 }
 744