src/lj_bcread.c

   1 /*
   2 ** Bytecode reader.
   3 ** Copyright (C) 2005-2017 Mike Pall. See Copyright Notice in luajit.h
   4 */
   5
   6 #define lj_bcread_c
   7 #define LUA_CORE
   8
   9 #include "lj_obj.h"
  10 #include "lj_gc.h"
  11 #include "lj_err.h"
  12 #include "lj_str.h"
  13 #include "lj_tab.h"
  14 #include "lj_bc.h"
  15 #if LJ_HASFFI
  16 #include "lj_ctype.h"
  17 #include "lj_cdata.h"
  18 #include "lualib.h"
  19 #endif
  20 #include "lj_lex.h"
  21 #include "lj_bcdump.h"
  22 #include "lj_state.h"
  23
  24 /* Reuse some lexer fields for our own purposes. */
  25 #define bcread_flags(ls)        ls->level
  26 #define bcread_swap(ls) \
  27   ((bcread_flags(ls) & BCDUMP_F_BE) != LJ_BE*BCDUMP_F_BE)
  28 #define bcread_oldtop(L, ls)    restorestack(L, ls->lastline)
  29 #define bcread_savetop(L, ls, top) \
  30   ls->lastline = (BCLine)savestack(L, (top))
  31
  32 /* -- Input buffer handling ----------------------------------------------- */
  33
  34 /* Throw reader error. */
  35 static LJ_NOINLINE void bcread_error(LexState *ls, ErrMsg em)
  36 {
  37   lua_State *L = ls->L;
  38   const char *name = ls->chunkarg;
  39   if (*name == BCDUMP_HEAD1) name = "(binary)";
  40   else if (*name == '@' || *name == '=') name++;
  41   lj_str_pushf(L, "%s: %s", name, err2msg(em));
  42   lj_err_throw(L, LUA_ERRSYNTAX);
  43 }
  44
  45 /* Resize input buffer. */
  46 static void bcread_resize(LexState *ls, MSize len)
  47 {
  48   if (ls->sb.sz < len) {
  49     MSize sz = ls->sb.sz * 2;
  50     while (len > sz) sz = sz * 2;
  51     lj_str_resizebuf(ls->L, &ls->sb, sz);
  52     /* Caveat: this may change ls->sb.buf which may affect ls->p. */
  53   }
  54 }
  55
  56 /* Refill buffer if needed. */
  57 static LJ_NOINLINE void bcread_fill(LexState *ls, MSize len, int need)
  58 {
  59   lua_assert(len != 0);
  60   if (len > LJ_MAX_MEM || ls->current < 0)
  61     bcread_error(ls, LJ_ERR_BCBAD);
  62   do {
  63     const char *buf;
  64     size_t size;
  65     if (ls->n) {  /* Copy remainder to buffer. */
  66       if (ls->sb.n) {  /* Move down in buffer. */
  67         lua_assert(ls->p + ls->n == ls->sb.buf + ls->sb.n);
  68         if (ls->n != ls->sb.n)
  69           memmove(ls->sb.buf, ls->p, ls->n);
  70       } else {  /* Copy from buffer provided by reader. */
  71         bcread_resize(ls, len);
  72         memcpy(ls->sb.buf, ls->p, ls->n);
  73       }
  74       ls->p = ls->sb.buf;
  75     }
  76     ls->sb.n = ls->n;
  77     buf = ls->rfunc(ls->L, ls->rdata, &size);  /* Get more data from reader. */
  78     if (buf == NULL || size == 0) {  /* EOF? */
  79       if (need) bcread_error(ls, LJ_ERR_BCBAD);
  80       ls->current = -1;  /* Only bad if we get called again. */
  81       break;
  82     }
  83     if (ls->sb.n) {  /* Append to buffer. */
  84       MSize n = ls->sb.n + (MSize)size;
  85       bcread_resize(ls, n < len ? len : n);
  86       memcpy(ls->sb.buf + ls->sb.n, buf, size);
  87       ls->n = ls->sb.n = n;
  88       ls->p = ls->sb.buf;
  89     } else {  /* Return buffer provided by reader. */
  90       ls->n = (MSize)size;
  91       ls->p = buf;
  92     }
  93   } while (ls->n < len);
  94 }
  95
  96 /* Need a certain number of bytes. */
  97 static LJ_AINLINE void bcread_need(LexState *ls, MSize len)
  98 {
  99   if (LJ_UNLIKELY(ls->n < len))
 100     bcread_fill(ls, len, 1);
 101 }
 102
 103 /* Want to read up to a certain number of bytes, but may need less. */
 104 static LJ_AINLINE void bcread_want(LexState *ls, MSize len)
 105 {
 106   if (LJ_UNLIKELY(ls->n < len))
 107     bcread_fill(ls, len, 0);
 108 }
 109
 110 #define bcread_dec(ls)          check_exp(ls->n > 0, ls->n--)
 111 #define bcread_consume(ls, len) check_exp(ls->n >= (len), ls->n -= (len))
 112
 113 /* Return memory block from buffer. */
 114 static uint8_t *bcread_mem(LexState *ls, MSize len)
 115 {
 116   uint8_t *p = (uint8_t *)ls->p;
 117   bcread_consume(ls, len);
 118   ls->p = (char *)p + len;
 119   return p;
 120 }
 121
 122 /* Copy memory block from buffer. */
 123 static void bcread_block(LexState *ls, void *q, MSize len)
 124 {
 125   memcpy(q, bcread_mem(ls, len), len);
 126 }
 127
 128 /* Read byte from buffer. */
 129 static LJ_AINLINE uint32_t bcread_byte(LexState *ls)
 130 {
 131   bcread_dec(ls);
 132   return (uint32_t)(uint8_t)*ls->p++;
 133 }
 134
 135 /* Read ULEB128 value from buffer. */
 136 static uint32_t bcread_uleb128(LexState *ls)
 137 {
 138   const uint8_t *p = (const uint8_t *)ls->p;
 139   uint32_t v = *p++;
 140   if (LJ_UNLIKELY(v >= 0x80)) {
 141     int sh = 0;
 142     v &= 0x7f;
 143     do {
 144      v |= ((*p & 0x7f) << (sh += 7));
 145      bcread_dec(ls);
 146    } while (*p++ >= 0x80);
 147   }
 148   bcread_dec(ls);
 149   ls->p = (char *)p;
 150   return v;
 151 }
 152
 153 /* Read top 32 bits of 33 bit ULEB128 value from buffer. */
 154 static uint32_t bcread_uleb128_33(LexState *ls)
 155 {
 156   const uint8_t *p = (const uint8_t *)ls->p;
 157   uint32_t v = (*p++ >> 1);
 158   if (LJ_UNLIKELY(v >= 0x40)) {
 159     int sh = -1;
 160     v &= 0x3f;
 161     do {
 162      v |= ((*p & 0x7f) << (sh += 7));
 163      bcread_dec(ls);
 164    } while (*p++ >= 0x80);
 165   }
 166   bcread_dec(ls);
 167   ls->p = (char *)p;
 168   return v;
 169 }
 170
 171 /* -- Bytecode reader ----------------------------------------------------- */
 172
 173 /* Read debug info of a prototype. */
 174 static void bcread_dbg(LexState *ls, GCproto *pt, MSize sizedbg)
 175 {
 176   void *lineinfo = (void *)proto_lineinfo(pt);
 177   bcread_block(ls, lineinfo, sizedbg);
 178   /* Swap lineinfo if the endianess differs. */
 179   if (bcread_swap(ls) && pt->numline >= 256) {
 180     MSize i, n = pt->sizebc-1;
 181     if (pt->numline < 65536) {
 182       uint16_t *p = (uint16_t *)lineinfo;
 183       for (i = 0; i < n; i++) p[i] = (uint16_t)((p[i] >> 8)|(p[i] << 8));
 184     } else {
 185       uint32_t *p = (uint32_t *)lineinfo;
 186       for (i = 0; i < n; i++) p[i] = lj_bswap(p[i]);
 187     }
 188   }
 189 }
 190
 191 /* Find pointer to varinfo. */
 192 static const void *bcread_varinfo(GCproto *pt)
 193 {
 194   const uint8_t *p = proto_uvinfo(pt);
 195   MSize n = pt->sizeuv;
 196   if (n) while (*p++ || --n) ;
 197   return p;
 198 }
 199
 200 /* Read a single constant key/value of a template table. */
 201 static void bcread_ktabk(LexState *ls, TValue *o)
 202 {
 203   MSize tp = bcread_uleb128(ls);
 204   if (tp >= BCDUMP_KTAB_STR) {
 205     MSize len = tp - BCDUMP_KTAB_STR;
 206     const char *p = (const char *)bcread_mem(ls, len);
 207     setstrV(ls->L, o, lj_str_new(ls->L, p, len));
 208   } else if (tp == BCDUMP_KTAB_INT) {
 209     setintV(o, (int32_t)bcread_uleb128(ls));
 210   } else if (tp == BCDUMP_KTAB_NUM) {
 211     o->u32.lo = bcread_uleb128(ls);
 212     o->u32.hi = bcread_uleb128(ls);
 213   } else {
 214     lua_assert(tp <= BCDUMP_KTAB_TRUE);
 215     setitype(o, ~tp);
 216   }
 217 }
 218
 219 /* Read a template table. */
 220 static GCtab *bcread_ktab(LexState *ls)
 221 {
 222   MSize narray = bcread_uleb128(ls);
 223   MSize nhash = bcread_uleb128(ls);
 224   GCtab *t = lj_tab_new(ls->L, narray, hsize2hbits(nhash));
 225   if (narray) {  /* Read array entries. */
 226     MSize i;
 227     TValue *o = tvref(t->array);
 228     for (i = 0; i < narray; i++, o++)
 229       bcread_ktabk(ls, o);
 230   }
 231   if (nhash) {  /* Read hash entries. */
 232     MSize i;
 233     for (i = 0; i < nhash; i++) {
 234       TValue key;
 235       bcread_ktabk(ls, &key);
 236       lua_assert(!tvisnil(&key));
 237       bcread_ktabk(ls, lj_tab_set(ls->L, t, &key));
 238     }
 239   }
 240   return t;
 241 }
 242
 243 /* Read GC constants of a prototype. */
 244 static void bcread_kgc(LexState *ls, GCproto *pt, MSize sizekgc)
 245 {
 246   MSize i;
 247   GCRef *kr = mref(pt->k, GCRef) - (ptrdiff_t)sizekgc;
 248   for (i = 0; i < sizekgc; i++, kr++) {
 249     MSize tp = bcread_uleb128(ls);
 250     if (tp >= BCDUMP_KGC_STR) {
 251       MSize len = tp - BCDUMP_KGC_STR;
 252       const char *p = (const char *)bcread_mem(ls, len);
 253       setgcref(*kr, obj2gco(lj_str_new(ls->L, p, len)));
 254     } else if (tp == BCDUMP_KGC_TAB) {
 255       setgcref(*kr, obj2gco(bcread_ktab(ls)));
 256 #if LJ_HASFFI
 257     } else if (tp != BCDUMP_KGC_CHILD) {
 258       CTypeID id = tp == BCDUMP_KGC_COMPLEX ? CTID_COMPLEX_DOUBLE :
 259                    tp == BCDUMP_KGC_I64 ? CTID_INT64 : CTID_UINT64;
 260       CTSize sz = tp == BCDUMP_KGC_COMPLEX ? 16 : 8;
 261       GCcdata *cd = lj_cdata_new_(ls->L, id, sz);
 262       TValue *p = (TValue *)cdataptr(cd);
 263       setgcref(*kr, obj2gco(cd));
 264       p[0].u32.lo = bcread_uleb128(ls);
 265       p[0].u32.hi = bcread_uleb128(ls);
 266       if (tp == BCDUMP_KGC_COMPLEX) {
 267         p[1].u32.lo = bcread_uleb128(ls);
 268         p[1].u32.hi = bcread_uleb128(ls);
 269       }
 270 #endif
 271     } else {
 272       lua_State *L = ls->L;
 273       lua_assert(tp == BCDUMP_KGC_CHILD);
 274       if (L->top <= bcread_oldtop(L, ls))  /* Stack underflow? */
 275         bcread_error(ls, LJ_ERR_BCBAD);
 276       L->top--;
 277       setgcref(*kr, obj2gco(protoV(L->top)));
 278     }
 279   }
 280 }
 281
 282 /* Read number constants of a prototype. */
 283 static void bcread_knum(LexState *ls, GCproto *pt, MSize sizekn)
 284 {
 285   MSize i;
 286   TValue *o = mref(pt->k, TValue);
 287   for (i = 0; i < sizekn; i++, o++) {
 288     int isnum = (ls->p[0] & 1);
 289     uint32_t lo = bcread_uleb128_33(ls);
 290     if (isnum) {
 291       o->u32.lo = lo;
 292       o->u32.hi = bcread_uleb128(ls);
 293     } else {
 294       setintV(o, lo);
 295     }
 296   }
 297 }
 298
 299 /* Read bytecode instructions. */
 300 static void bcread_bytecode(LexState *ls, GCproto *pt, MSize sizebc)
 301 {
 302   BCIns *bc = proto_bc(pt);
 303   bc[0] = BCINS_AD((pt->flags & PROTO_VARARG) ? BC_FUNCV : BC_FUNCF,
 304                    pt->framesize, 0);
 305   bcread_block(ls, bc+1, (sizebc-1)*(MSize)sizeof(BCIns));
 306   /* Swap bytecode instructions if the endianess differs. */
 307   if (bcread_swap(ls)) {
 308     MSize i;
 309     for (i = 1; i < sizebc; i++) bc[i] = lj_bswap(bc[i]);
 310   }
 311 }
 312
 313 /* Read upvalue refs. */
 314 static void bcread_uv(LexState *ls, GCproto *pt, MSize sizeuv)
 315 {
 316   if (sizeuv) {
 317     uint16_t *uv = proto_uv(pt);
 318     bcread_block(ls, uv, sizeuv*2);
 319     /* Swap upvalue refs if the endianess differs. */
 320     if (bcread_swap(ls)) {
 321       MSize i;
 322       for (i = 0; i < sizeuv; i++)
 323         uv[i] = (uint16_t)((uv[i] >> 8)|(uv[i] << 8));
 324     }
 325   }
 326 }
 327
 328 /* Read a prototype. */
 329 static GCproto *bcread_proto(LexState *ls)
 330 {
 331   GCproto *pt;
 332   MSize framesize, numparams, flags, sizeuv, sizekgc, sizekn, sizebc, sizept;
 333   MSize ofsk, ofsuv, ofsdbg;
 334   MSize sizedbg = 0;
 335   BCLine firstline = 0, numline = 0;
 336   MSize len, startn;
 337
 338   /* Read length. */
 339   if (ls->n > 0 && ls->p[0] == 0) {  /* Shortcut EOF. */
 340     ls->n--; ls->p++;
 341     return NULL;
 342   }
 343   bcread_want(ls, 5);
 344   len = bcread_uleb128(ls);
 345   if (!len) return NULL;  /* EOF */
 346   bcread_need(ls, len);
 347   startn = ls->n;
 348
 349   /* Read prototype header. */
 350   flags = bcread_byte(ls);
 351   numparams = bcread_byte(ls);
 352   framesize = bcread_byte(ls);
 353   sizeuv = bcread_byte(ls);
 354   sizekgc = bcread_uleb128(ls);
 355   sizekn = bcread_uleb128(ls);
 356   sizebc = bcread_uleb128(ls) + 1;
 357   if (!(bcread_flags(ls) & BCDUMP_F_STRIP)) {
 358     sizedbg = bcread_uleb128(ls);
 359     if (sizedbg) {
 360       firstline = bcread_uleb128(ls);
 361       numline = bcread_uleb128(ls);
 362     }
 363   }
 364
 365   /* Calculate total size of prototype including all colocated arrays. */
 366   sizept = (MSize)sizeof(GCproto) +
 367            sizebc*(MSize)sizeof(BCIns) +
 368            sizekgc*(MSize)sizeof(GCRef);
 369   sizept = (sizept + (MSize)sizeof(TValue)-1) & ~((MSize)sizeof(TValue)-1);
 370   ofsk = sizept; sizept += sizekn*(MSize)sizeof(TValue);
 371   ofsuv = sizept; sizept += ((sizeuv+1)&~1)*2;
 372   ofsdbg = sizept; sizept += sizedbg;
 373
 374   /* Allocate prototype object and initialize its fields. */
 375   pt = (GCproto *)lj_mem_newgco(ls->L, (MSize)sizept);
 376   pt->gct = ~LJ_TPROTO;
 377   pt->numparams = (uint8_t)numparams;
 378   pt->framesize = (uint8_t)framesize;
 379   pt->sizebc = sizebc;
 380   setmref(pt->k, (char *)pt + ofsk);
 381   setmref(pt->uv, (char *)pt + ofsuv);
 382   pt->sizekgc = 0;  /* Set to zero until fully initialized. */
 383   pt->sizekn = sizekn;
 384   pt->sizept = sizept;
 385   pt->sizeuv = (uint8_t)sizeuv;
 386   pt->flags = (uint8_t)flags;
 387   pt->trace = 0;
 388   setgcref(pt->chunkname, obj2gco(ls->chunkname));
 389
 390   /* Close potentially uninitialized gap between bc and kgc. */
 391   *(uint32_t *)((char *)pt + ofsk - sizeof(GCRef)*(sizekgc+1)) = 0;
 392
 393   /* Read bytecode instructions and upvalue refs. */
 394   bcread_bytecode(ls, pt, sizebc);
 395   bcread_uv(ls, pt, sizeuv);
 396
 397   /* Read constants. */
 398   bcread_kgc(ls, pt, sizekgc);
 399   pt->sizekgc = sizekgc;
 400   bcread_knum(ls, pt, sizekn);
 401
 402   /* Read and initialize debug info. */
 403   pt->firstline = firstline;
 404   pt->numline = numline;
 405   if (sizedbg) {
 406     MSize sizeli = (sizebc-1) << (numline < 256 ? 0 : numline < 65536 ? 1 : 2);
 407     setmref(pt->lineinfo, (char *)pt + ofsdbg);
 408     setmref(pt->uvinfo, (char *)pt + ofsdbg + sizeli);
 409     bcread_dbg(ls, pt, sizedbg);
 410     setmref(pt->varinfo, bcread_varinfo(pt));
 411   } else {
 412     setmref(pt->lineinfo, NULL);
 413     setmref(pt->uvinfo, NULL);
 414     setmref(pt->varinfo, NULL);
 415   }
 416
 417   if (len != startn - ls->n)
 418     bcread_error(ls, LJ_ERR_BCBAD);
 419   return pt;
 420 }
 421
 422 /* Read and check header of bytecode dump. */
 423 static int bcread_header(LexState *ls)
 424 {
 425   uint32_t flags;
 426   bcread_want(ls, 3+5+5);
 427   if (bcread_byte(ls) != BCDUMP_HEAD2 ||
 428       bcread_byte(ls) != BCDUMP_HEAD3 ||
 429       bcread_byte(ls) != BCDUMP_VERSION) return 0;
 430   bcread_flags(ls) = flags = bcread_uleb128(ls);
 431   if ((flags & ~(BCDUMP_F_KNOWN)) != 0) return 0;
 432   if ((flags & BCDUMP_F_FFI)) {
 433 #if LJ_HASFFI
 434     lua_State *L = ls->L;
 435     if (!ctype_ctsG(G(L))) {
 436       ptrdiff_t oldtop = savestack(L, L->top);
 437       luaopen_ffi(L);  /* Load FFI library on-demand. */
 438       L->top = restorestack(L, oldtop);
 439     }
 440 #else
 441     return 0;
 442 #endif
 443   }
 444   if ((flags & BCDUMP_F_STRIP)) {
 445     ls->chunkname = lj_str_newz(ls->L, ls->chunkarg);
 446   } else {
 447     MSize len = bcread_uleb128(ls);
 448     bcread_need(ls, len);
 449     ls->chunkname = lj_str_new(ls->L, (const char *)bcread_mem(ls, len), len);
 450   }
 451   return 1;  /* Ok. */
 452 }
 453
 454 /* Read a bytecode dump. */
 455 GCproto *lj_bcread(LexState *ls)
 456 {
 457   lua_State *L = ls->L;
 458   lua_assert(ls->current == BCDUMP_HEAD1);
 459   bcread_savetop(L, ls, L->top);
 460   lj_str_resetbuf(&ls->sb);
 461   /* Check for a valid bytecode dump header. */
 462   if (!bcread_header(ls))
 463     bcread_error(ls, LJ_ERR_BCFMT);
 464   for (;;) {  /* Process all prototypes in the bytecode dump. */
 465     GCproto *pt = bcread_proto(ls);
 466     if (!pt) break;
 467     setprotoV(L, L->top, pt);
 468     incr_top(L);
 469   }
 470   if ((int32_t)ls->n > 0 || L->top-1 != bcread_oldtop(L, ls))
 471     bcread_error(ls, LJ_ERR_BCBAD);
 472   /* Pop off last prototype. */
 473   L->top--;
 474   return protoV(L->top);
 475 }
 476