src/lj_bcread.c

   1 /*
   2 ** Bytecode reader.
   3 ** Copyright (C) 2005-2012 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 #endif
  19 #include "lj_lex.h"
  20 #include "lj_bcdump.h"
  21 #include "lj_state.h"
  22
  23 /* Reuse some lexer fields for our own purposes. */
  24 #define bcread_flags(ls)        ls->level
  25 #define bcread_swap(ls) \
  26   ((bcread_flags(ls) & BCDUMP_F_BE) != LJ_BE*BCDUMP_F_BE)
  27 #define bcread_oldtop(L, ls)    restorestack(L, ls->lastline)
  28 #define bcread_savetop(L, ls, top) \
  29   ls->lastline = (BCLine)savestack(L, (top))
  30
  31 /* -- Input buffer handling ----------------------------------------------- */
  32
  33 /* Throw reader error. */
  34 static LJ_NOINLINE void bcread_error(LexState *ls, ErrMsg em)
  35 {
  36   lua_State *L = ls->L;
  37   const char *name = ls->chunkarg;
  38   if (*name == BCDUMP_HEAD1) name = "(binary)";
  39   else if (*name == '@' || *name == '=') name++;
  40   lj_str_pushf(L, "%s: %s", name, err2msg(em));
  41   lj_err_throw(L, LUA_ERRSYNTAX);
  42 }
  43
  44 /* Resize input buffer. */
  45 static void bcread_resize(LexState *ls, MSize len)
  46 {
  47   if (ls->sb.sz < len) {
  48     MSize sz = ls->sb.sz * 2;
  49     while (len > sz) sz = sz * 2;
  50     lj_str_resizebuf(ls->L, &ls->sb, sz);
  51     /* Caveat: this may change ls->sb.buf which may affect ls->p. */
  52   }
  53 }
  54
  55 /* Refill buffer if needed. */
  56 static LJ_NOINLINE void bcread_fill(LexState *ls, MSize len, int need)
  57 {
  58   lua_assert(len != 0);
  59   if (len > LJ_MAX_MEM || ls->current < 0)
  60     bcread_error(ls, LJ_ERR_BCBAD);
  61   do {
  62     const char *buf;
  63     size_t size;
  64     if (ls->n) {  /* Copy remainder to buffer. */
  65       if (ls->sb.n) {  /* Move down in buffer. */
  66         lua_assert(ls->p + ls->n == ls->sb.buf + ls->sb.n);
  67         if (ls->n != ls->sb.n)
  68           memmove(ls->sb.buf, ls->p, ls->n);
  69       } else {  /* Copy from buffer provided by reader. */
  70         bcread_resize(ls, len);
  71         memcpy(ls->sb.buf, ls->p, ls->n);
  72       }
  73       ls->p = ls->sb.buf;
  74     }
  75     ls->sb.n = ls->n;
  76     buf = ls->rfunc(ls->L, ls->rdata, &size);  /* Get more data from reader. */
  77     if (buf == NULL || size == 0) {  /* EOF? */
  78       if (need) bcread_error(ls, LJ_ERR_BCBAD);
  79       ls->current = -1;  /* Only bad if we get called again. */
  80       break;
  81     }
  82     if (ls->sb.n) {  /* Append to buffer. */
  83       MSize n = ls->sb.n + (MSize)size;
  84       bcread_resize(ls, n < len ? len : n);
  85       memcpy(ls->sb.buf + ls->sb.n, buf, size);
  86       ls->n = ls->sb.n = n;
  87       ls->p = ls->sb.buf;
  88     } else {  /* Return buffer provided by reader. */
  89       ls->n = (MSize)size;
  90       ls->p = buf;
  91     }
  92   } while (ls->n < len);
  93 }
  94
  95 /* Need a certain number of bytes. */
  96 static LJ_AINLINE void bcread_need(LexState *ls, MSize len)
  97 {
  98   if (LJ_UNLIKELY(ls->n < len))
  99     bcread_fill(ls, len, 1);
 100 }
 101
 102 /* Want to read up to a certain number of bytes, but may need less. */
 103 static LJ_AINLINE void bcread_want(LexState *ls, MSize len)
 104 {
 105   if (LJ_UNLIKELY(ls->n < len))
 106     bcread_fill(ls, len, 0);
 107 }
 108
 109 #define bcread_dec(ls)          check_exp(ls->n > 0, ls->n--)
 110 #define bcread_consume(ls, len) check_exp(ls->n >= (len), ls->n -= (len))
 111
 112 /* Return memory block from buffer. */
 113 static uint8_t *bcread_mem(LexState *ls, MSize len)
 114 {
 115   uint8_t *p = (uint8_t *)ls->p;
 116   bcread_consume(ls, len);
 117   ls->p = (char *)p + len;
 118   return p;
 119 }
 120
 121 /* Copy memory block from buffer. */
 122 static void bcread_block(LexState *ls, void *q, MSize len)
 123 {
 124   memcpy(q, bcread_mem(ls, len), len);
 125 }
 126
 127 /* Read byte from buffer. */
 128 static LJ_AINLINE uint32_t bcread_byte(LexState *ls)
 129 {
 130   bcread_dec(ls);
 131   return (uint32_t)(uint8_t)*ls->p++;
 132 }
 133
 134 /* Read ULEB128 value from buffer. */
 135 static uint32_t bcread_uleb128(LexState *ls)
 136 {
 137   const uint8_t *p = (const uint8_t *)ls->p;
 138   uint32_t v = *p++;
 139   if (LJ_UNLIKELY(v >= 0x80)) {
 140     int sh = 0;
 141     v &= 0x7f;
 142     do {
 143      v |= ((*p & 0x7f) << (sh += 7));
 144      bcread_dec(ls);
 145    } while (*p++ >= 0x80);
 146   }
 147   bcread_dec(ls);
 148   ls->p = (char *)p;
 149   return v;
 150 }
 151
 152 /* Read top 32 bits of 33 bit ULEB128 value from buffer. */
 153 static uint32_t bcread_uleb128_33(LexState *ls)
 154 {
 155   const uint8_t *p = (const uint8_t *)ls->p;
 156   uint32_t v = (*p++ >> 1);
 157   if (LJ_UNLIKELY(v >= 0x40)) {
 158     int sh = -1;
 159     v &= 0x3f;
 160     do {
 161      v |= ((*p & 0x7f) << (sh += 7));
 162      bcread_dec(ls);
 163    } while (*p++ >= 0x80);
 164   }
 165   bcread_dec(ls);
 166   ls->p = (char *)p;
 167   return v;
 168 }
 169
 170 /* -- Bytecode reader ----------------------------------------------------- */
 171
 172 /* Read debug info of a prototype. */
 173 static void bcread_dbg(LexState *ls, GCproto *pt, MSize sizedbg)
 174 {
 175   void *lineinfo = (void *)proto_lineinfo(pt);
 176   bcread_block(ls, lineinfo, sizedbg);
 177   /* Swap lineinfo if the endianess differs. */
 178   if (bcread_swap(ls) && pt->numline >= 256) {
 179     MSize i, n = pt->sizebc-1;
 180     if (pt->numline < 65536) {
 181       uint16_t *p = (uint16_t *)lineinfo;
 182       for (i = 0; i < n; i++) p[i] = (uint16_t)((p[i] >> 8)|(p[i] << 8));
 183     } else {
 184       uint32_t *p = (uint32_t *)lineinfo;
 185       for (i = 0; i < n; i++) p[i] = lj_bswap(p[i]);
 186     }
 187   }
 188 }
 189
 190 /* Find pointer to varinfo. */
 191 static const void *bcread_varinfo(GCproto *pt)
 192 {
 193   const uint8_t *p = proto_uvinfo(pt);
 194   MSize n = pt->sizeuv;
 195   if (n) while (*p++ || --n) ;
 196   return p;
 197 }
 198
 199 /* Read a single constant key/value of a template table. */
 200 static void bcread_ktabk(LexState *ls, TValue *o)
 201 {
 202   MSize tp = bcread_uleb128(ls);
 203   if (tp >= BCDUMP_KTAB_STR) {
 204     MSize len = tp - BCDUMP_KTAB_STR;
 205     const char *p = (const char *)bcread_mem(ls, len);
 206     setstrV(ls->L, o, lj_str_new(ls->L, p, len));
 207   } else if (tp == BCDUMP_KTAB_INT) {
 208     setintV(o, (int32_t)bcread_uleb128(ls));
 209   } else if (tp == BCDUMP_KTAB_NUM) {
 210     o->u32.lo = bcread_uleb128(ls);
 211     o->u32.hi = bcread_uleb128(ls);
 212   } else {
 213     lua_assert(tp <= BCDUMP_KTAB_TRUE);
 214     setitype(o, ~tp);
 215   }
 216 }
 217
 218 /* Read a template table. */
 219 static GCtab *bcread_ktab(LexState *ls)
 220 {
 221   MSize narray = bcread_uleb128(ls);
 222   MSize nhash = bcread_uleb128(ls);
 223   GCtab *t = lj_tab_new(ls->L, narray, hsize2hbits(nhash));
 224   if (narray) {  /* Read array entries. */
 225     MSize i;
 226     TValue *o = tvref(t->array);
 227     for (i = 0; i < narray; i++, o++)
 228       bcread_ktabk(ls, o);
 229   }
 230   if (nhash) {  /* Read hash entries. */
 231     MSize i;
 232     for (i = 0; i < nhash; i++) {
 233       TValue key;
 234       bcread_ktabk(ls, &key);
 235       lua_assert(!tvisnil(&key));
 236       bcread_ktabk(ls, lj_tab_set(ls->L, t, &key));
 237     }
 238   }
 239   return t;
 240 }
 241
 242 /* Read GC constants of a prototype. */
 243 static void bcread_kgc(LexState *ls, GCproto *pt, MSize sizekgc)
 244 {
 245   MSize i;
 246   GCRef *kr = mref(pt->k, GCRef) - (ptrdiff_t)sizekgc;
 247   for (i = 0; i < sizekgc; i++, kr++) {
 248     MSize tp = bcread_uleb128(ls);
 249     if (tp >= BCDUMP_KGC_STR) {
 250       MSize len = tp - BCDUMP_KGC_STR;
 251       const char *p = (const char *)bcread_mem(ls, len);
 252       setgcref(*kr, obj2gco(lj_str_new(ls->L, p, len)));
 253     } else if (tp == BCDUMP_KGC_TAB) {
 254       setgcref(*kr, obj2gco(bcread_ktab(ls)));
 255 #if LJ_HASFFI
 256     } else if (tp != BCDUMP_KGC_CHILD) {
 257       CTypeID id = tp == BCDUMP_KGC_COMPLEX ? CTID_COMPLEX_DOUBLE :
 258                    tp == BCDUMP_KGC_I64 ? CTID_INT64 : CTID_UINT64;
 259       CTSize sz = tp == BCDUMP_KGC_COMPLEX ? 16 : 8;
 260       GCcdata *cd = lj_cdata_new_(ls->L, id, sz);
 261       TValue *p = (TValue *)cdataptr(cd);
 262       setgcref(*kr, obj2gco(cd));
 263       p[0].u32.lo = bcread_uleb128(ls);
 264       p[0].u32.hi = bcread_uleb128(ls);
 265       if (tp == BCDUMP_KGC_COMPLEX) {
 266         p[1].u32.lo = bcread_uleb128(ls);
 267         p[1].u32.hi = bcread_uleb128(ls);
 268       }
 269 #endif
 270     } else {
 271       lua_State *L = ls->L;
 272       lua_assert(tp == BCDUMP_KGC_CHILD);
 273       if (L->top <= bcread_oldtop(L, ls))  /* Stack underflow? */
 274         bcread_error(ls, LJ_ERR_BCBAD);
 275       L->top--;
 276       setgcref(*kr, obj2gco(protoV(L->top)));
 277     }
 278   }
 279 }
 280
 281 /* Read number constants of a prototype. */
 282 static void bcread_knum(LexState *ls, GCproto *pt, MSize sizekn)
 283 {
 284   MSize i;
 285   TValue *o = mref(pt->k, TValue);
 286   for (i = 0; i < sizekn; i++, o++) {
 287     int isnum = (ls->p[0] & 1);
 288     uint32_t lo = bcread_uleb128_33(ls);
 289     if (isnum) {
 290       o->u32.lo = lo;
 291       o->u32.hi = bcread_uleb128(ls);
 292     } else {
 293       setintV(o, lo);
 294     }
 295   }
 296 }
 297
 298 /* Read bytecode instructions. */
 299 static void bcread_bytecode(LexState *ls, GCproto *pt, MSize sizebc)
 300 {
 301   BCIns *bc = proto_bc(pt);
 302   bc[0] = BCINS_AD((pt->flags & PROTO_VARARG) ? BC_FUNCV : BC_FUNCF,
 303                    pt->framesize, 0);
 304   bcread_block(ls, bc+1, (sizebc-1)*(MSize)sizeof(BCIns));
 305   /* Swap bytecode instructions if the endianess differs. */
 306   if (bcread_swap(ls)) {
 307     MSize i;
 308     for (i = 1; i < sizebc; i++) bc[i] = lj_bswap(bc[i]);
 309   }
 310 }
 311
 312 /* Read upvalue refs. */
 313 static void bcread_uv(LexState *ls, GCproto *pt, MSize sizeuv)
 314 {
 315   if (sizeuv) {
 316     uint16_t *uv = proto_uv(pt);
 317     bcread_block(ls, uv, sizeuv*2);
 318     /* Swap upvalue refs if the endianess differs. */
 319     if (bcread_swap(ls)) {
 320       MSize i;
 321       for (i = 0; i < sizeuv; i++)
 322         uv[i] = (uint16_t)((uv[i] >> 8)|(uv[i] << 8));
 323     }
 324   }
 325 }
 326
 327 /* Read a prototype. */
 328 static GCproto *bcread_proto(LexState *ls)
 329 {
 330   GCproto *pt;
 331   MSize framesize, numparams, flags, sizeuv, sizekgc, sizekn, sizebc, sizept;
 332   MSize ofsk, ofsuv, ofsdbg;
 333   MSize sizedbg = 0;
 334   BCLine firstline = 0, numline = 0;
 335   MSize len, startn;
 336
 337   /* Read length. */
 338   if (ls->n > 0 && ls->p[0] == 0) {  /* Shortcut EOF. */
 339     ls->n--; ls->p++;
 340     return NULL;
 341   }
 342   bcread_want(ls, 5);
 343   len = bcread_uleb128(ls);
 344   if (!len) return NULL;  /* EOF */
 345   bcread_need(ls, len);
 346   startn = ls->n;
 347
 348   /* Read prototype header. */
 349   flags = bcread_byte(ls);
 350   numparams = bcread_byte(ls);
 351   framesize = bcread_byte(ls);
 352   sizeuv = bcread_byte(ls);
 353   sizekgc = bcread_uleb128(ls);
 354   sizekn = bcread_uleb128(ls);
 355   sizebc = bcread_uleb128(ls) + 1;
 356   if (!(bcread_flags(ls) & BCDUMP_F_STRIP)) {
 357     sizedbg = bcread_uleb128(ls);
 358     if (sizedbg) {
 359       firstline = bcread_uleb128(ls);
 360       numline = bcread_uleb128(ls);
 361     }
 362   }
 363
 364   /* Calculate total size of prototype including all colocated arrays. */
 365   sizept = (MSize)sizeof(GCproto) +
 366            sizebc*(MSize)sizeof(BCIns) +
 367            sizekgc*(MSize)sizeof(GCRef);
 368   sizept = (sizept + (MSize)sizeof(TValue)-1) & ~((MSize)sizeof(TValue)-1);
 369   ofsk = sizept; sizept += sizekn*(MSize)sizeof(TValue);
 370   ofsuv = sizept; sizept += ((sizeuv+1)&~1)*2;
 371   ofsdbg = sizept; sizept += sizedbg;
 372
 373   /* Allocate prototype object and initialize its fields. */
 374   pt = (GCproto *)lj_mem_newgco(ls->L, (MSize)sizept);
 375   pt->gct = ~LJ_TPROTO;
 376   pt->numparams = (uint8_t)numparams;
 377   pt->framesize = (uint8_t)framesize;
 378   pt->sizebc = sizebc;
 379   setmref(pt->k, (char *)pt + ofsk);
 380   setmref(pt->uv, (char *)pt + ofsuv);
 381   pt->sizekgc = 0;  /* Set to zero until fully initialized. */
 382   pt->sizekn = sizekn;
 383   pt->sizept = sizept;
 384   pt->sizeuv = (uint8_t)sizeuv;
 385   pt->flags = (uint8_t)flags;
 386   pt->trace = 0;
 387   setgcref(pt->chunkname, obj2gco(ls->chunkname));
 388
 389   /* Close potentially uninitialized gap between bc and kgc. */
 390   *(uint32_t *)((char *)pt + ofsk - sizeof(GCRef)*(sizekgc+1)) = 0;
 391
 392   /* Read bytecode instructions and upvalue refs. */
 393   bcread_bytecode(ls, pt, sizebc);
 394   bcread_uv(ls, pt, sizeuv);
 395
 396   /* Read constants. */
 397   bcread_kgc(ls, pt, sizekgc);
 398   pt->sizekgc = sizekgc;
 399   bcread_knum(ls, pt, sizekn);
 400
 401   /* Read and initialize debug info. */
 402   pt->firstline = firstline;
 403   pt->numline = numline;
 404   if (sizedbg) {
 405     MSize sizeli = (sizebc-1) << (numline < 256 ? 0 : numline < 65536 ? 1 : 2);
 406     setmref(pt->lineinfo, (char *)pt + ofsdbg);
 407     setmref(pt->uvinfo, (char *)pt + ofsdbg + sizeli);
 408     bcread_dbg(ls, pt, sizedbg);
 409     setmref(pt->varinfo, bcread_varinfo(pt));
 410   } else {
 411     setmref(pt->lineinfo, NULL);
 412     setmref(pt->uvinfo, NULL);
 413     setmref(pt->varinfo, NULL);
 414   }
 415
 416   if (len != startn - ls->n)
 417     bcread_error(ls, LJ_ERR_BCBAD);
 418   return pt;
 419 }
 420
 421 /* Read and check header of bytecode dump. */
 422 static int bcread_header(LexState *ls)
 423 {
 424   uint32_t flags;
 425   bcread_want(ls, 3+5+5);
 426   if (bcread_byte(ls) != BCDUMP_HEAD2 ||
 427       bcread_byte(ls) != BCDUMP_HEAD3 ||
 428       bcread_byte(ls) != BCDUMP_VERSION) return 0;
 429   bcread_flags(ls) = flags = bcread_uleb128(ls);
 430   if ((flags & ~(BCDUMP_F_KNOWN)) != 0) return 0;
 431 #if !LJ_HASFFI
 432   if ((flags & BCDUMP_F_FFI)) return 0;
 433 #endif
 434   if ((flags & BCDUMP_F_STRIP)) {
 435     ls->chunkname = lj_str_newz(ls->L, ls->chunkarg);
 436   } else {
 437     MSize len = bcread_uleb128(ls);
 438     bcread_need(ls, len);
 439     ls->chunkname = lj_str_new(ls->L, (const char *)bcread_mem(ls, len), len);
 440   }
 441   return 1;  /* Ok. */
 442 }
 443
 444 /* Read a bytecode dump. */
 445 GCproto *lj_bcread(LexState *ls)
 446 {
 447   lua_State *L = ls->L;
 448   lua_assert(ls->current == BCDUMP_HEAD1);
 449   bcread_savetop(L, ls, L->top);
 450   lj_str_resetbuf(&ls->sb);
 451   /* Check for a valid bytecode dump header. */
 452   if (!bcread_header(ls))
 453     bcread_error(ls, LJ_ERR_BCFMT);
 454   for (;;) {  /* Process all prototypes in the bytecode dump. */
 455     GCproto *pt = bcread_proto(ls);
 456     if (!pt) break;
 457     setprotoV(L, L->top, pt);
 458     incr_top(L);
 459   }
 460   if ((int32_t)ls->n > 0 || L->top-1 != bcread_oldtop(L, ls))
 461     bcread_error(ls, LJ_ERR_BCBAD);
 462   /* Pop off last prototype. */
 463   L->top--;
 464   return protoV(L->top);
 465 }
 466