source/libs/luajit/LuaJIT-src/src/lj_cdata.c

   1 /*
   2 ** C data management.
   3 ** Copyright (C) 2005-2015 Mike Pall. See Copyright Notice in luajit.h
   4 */
   5
   6 #include "lj_obj.h"
   7
   8 #if LJ_HASFFI
   9
  10 #include "lj_gc.h"
  11 #include "lj_err.h"
  12 #include "lj_tab.h"
  13 #include "lj_ctype.h"
  14 #include "lj_cconv.h"
  15 #include "lj_cdata.h"
  16
  17 /* -- C data allocation --------------------------------------------------- */
  18
  19 /* Allocate a new C data object holding a reference to another object. */
  20 GCcdata *lj_cdata_newref(CTState *cts, const void *p, CTypeID id)
  21 {
  22   CTypeID refid = lj_ctype_intern(cts, CTINFO_REF(id), CTSIZE_PTR);
  23   GCcdata *cd = lj_cdata_new(cts, refid, CTSIZE_PTR);
  24   *(const void **)cdataptr(cd) = p;
  25   return cd;
  26 }
  27
  28 /* Allocate variable-sized or specially aligned C data object. */
  29 GCcdata *lj_cdata_newv(lua_State *L, CTypeID id, CTSize sz, CTSize align)
  30 {
  31   global_State *g;
  32   MSize extra = sizeof(GCcdataVar) + sizeof(GCcdata) +
  33                 (align > CT_MEMALIGN ? (1u<<align) - (1u<<CT_MEMALIGN) : 0);
  34   char *p = lj_mem_newt(L, extra + sz, char);
  35   uintptr_t adata = (uintptr_t)p + sizeof(GCcdataVar) + sizeof(GCcdata);
  36   uintptr_t almask = (1u << align) - 1u;
  37   GCcdata *cd = (GCcdata *)(((adata + almask) & ~almask) - sizeof(GCcdata));
  38   lua_assert((char *)cd - p < 65536);
  39   cdatav(cd)->offset = (uint16_t)((char *)cd - p);
  40   cdatav(cd)->extra = extra;
  41   cdatav(cd)->len = sz;
  42   g = G(L);
  43   setgcrefr(cd->nextgc, g->gc.root);
  44   setgcref(g->gc.root, obj2gco(cd));
  45   newwhite(g, obj2gco(cd));
  46   cd->marked |= 0x80;
  47   cd->gct = ~LJ_TCDATA;
  48   cd->ctypeid = id;
  49   return cd;
  50 }
  51
  52 /* Free a C data object. */
  53 void LJ_FASTCALL lj_cdata_free(global_State *g, GCcdata *cd)
  54 {
  55   if (LJ_UNLIKELY(cd->marked & LJ_GC_CDATA_FIN)) {
  56     GCobj *root;
  57     makewhite(g, obj2gco(cd));
  58     markfinalized(obj2gco(cd));
  59     if ((root = gcref(g->gc.mmudata)) != NULL) {
  60       setgcrefr(cd->nextgc, root->gch.nextgc);
  61       setgcref(root->gch.nextgc, obj2gco(cd));
  62       setgcref(g->gc.mmudata, obj2gco(cd));
  63     } else {
  64       setgcref(cd->nextgc, obj2gco(cd));
  65       setgcref(g->gc.mmudata, obj2gco(cd));
  66     }
  67   } else if (LJ_LIKELY(!cdataisv(cd))) {
  68     CType *ct = ctype_raw(ctype_ctsG(g), cd->ctypeid);
  69     CTSize sz = ctype_hassize(ct->info) ? ct->size : CTSIZE_PTR;
  70     lua_assert(ctype_hassize(ct->info) || ctype_isfunc(ct->info) ||
  71                ctype_isextern(ct->info));
  72     lj_mem_free(g, cd, sizeof(GCcdata) + sz);
  73   } else {
  74     lj_mem_free(g, memcdatav(cd), sizecdatav(cd));
  75   }
  76 }
  77
  78 void lj_cdata_setfin(lua_State *L, GCcdata *cd, GCobj *obj, uint32_t it)
  79 {
  80   GCtab *t = ctype_ctsG(G(L))->finalizer;
  81   if (gcref(t->metatable)) {
  82     /* Add cdata to finalizer table, if still enabled. */
  83     TValue *tv, tmp;
  84     setcdataV(L, &tmp, cd);
  85     lj_gc_anybarriert(L, t);
  86     tv = lj_tab_set(L, t, &tmp);
  87     setgcV(L, tv, obj, it);
  88     if (!tvisnil(tv))
  89       cd->marked |= LJ_GC_CDATA_FIN;
  90     else
  91       cd->marked &= ~LJ_GC_CDATA_FIN;
  92   }
  93 }
  94
  95 /* -- C data indexing ----------------------------------------------------- */
  96
  97 /* Index C data by a TValue. Return CType and pointer. */
  98 CType *lj_cdata_index(CTState *cts, GCcdata *cd, cTValue *key, uint8_t **pp,
  99                       CTInfo *qual)
 100 {
 101   uint8_t *p = (uint8_t *)cdataptr(cd);
 102   CType *ct = ctype_get(cts, cd->ctypeid);
 103   ptrdiff_t idx;
 104
 105   /* Resolve reference for cdata object. */
 106   if (ctype_isref(ct->info)) {
 107     lua_assert(ct->size == CTSIZE_PTR);
 108     p = *(uint8_t **)p;
 109     ct = ctype_child(cts, ct);
 110   }
 111
 112 collect_attrib:
 113   /* Skip attributes and collect qualifiers. */
 114   while (ctype_isattrib(ct->info)) {
 115     if (ctype_attrib(ct->info) == CTA_QUAL) *qual |= ct->size;
 116     ct = ctype_child(cts, ct);
 117   }
 118   lua_assert(!ctype_isref(ct->info));  /* Interning rejects refs to refs. */
 119
 120   if (tvisint(key)) {
 121     idx = (ptrdiff_t)intV(key);
 122     goto integer_key;
 123   } else if (tvisnum(key)) {  /* Numeric key. */
 124 #ifdef _MSC_VER
 125     /* Workaround for MSVC bug. */
 126     volatile
 127 #endif
 128     lua_Number n = numV(key);
 129     idx = LJ_64 ? (ptrdiff_t)n : (ptrdiff_t)lj_num2int(n);
 130   integer_key:
 131     if (ctype_ispointer(ct->info)) {
 132       CTSize sz = lj_ctype_size(cts, ctype_cid(ct->info));  /* Element size. */
 133       if (sz == CTSIZE_INVALID)
 134         lj_err_caller(cts->L, LJ_ERR_FFI_INVSIZE);
 135       if (ctype_isptr(ct->info)) {
 136         p = (uint8_t *)cdata_getptr(p, ct->size);
 137       } else if ((ct->info & (CTF_VECTOR|CTF_COMPLEX))) {
 138         if ((ct->info & CTF_COMPLEX)) idx &= 1;
 139         *qual |= CTF_CONST;  /* Valarray elements are constant. */
 140       }
 141       *pp = p + idx*(int32_t)sz;
 142       return ct;
 143     }
 144   } else if (tviscdata(key)) {  /* Integer cdata key. */
 145     GCcdata *cdk = cdataV(key);
 146     CType *ctk = ctype_raw(cts, cdk->ctypeid);
 147     if (ctype_isenum(ctk->info)) ctk = ctype_child(cts, ctk);
 148     if (ctype_isinteger(ctk->info)) {
 149       lj_cconv_ct_ct(cts, ctype_get(cts, CTID_INT_PSZ), ctk,
 150                      (uint8_t *)&idx, cdataptr(cdk), 0);
 151       goto integer_key;
 152     }
 153   } else if (tvisstr(key)) {  /* String key. */
 154     GCstr *name = strV(key);
 155     if (ctype_isstruct(ct->info)) {
 156       CTSize ofs;
 157       CType *fct = lj_ctype_getfieldq(cts, ct, name, &ofs, qual);
 158       if (fct) {
 159         *pp = p + ofs;
 160         return fct;
 161       }
 162     } else if (ctype_iscomplex(ct->info)) {
 163       if (name->len == 2) {
 164         *qual |= CTF_CONST;  /* Complex fields are constant. */
 165         if (strdata(name)[0] == 'r' && strdata(name)[1] == 'e') {
 166           *pp = p;
 167           return ct;
 168         } else if (strdata(name)[0] == 'i' && strdata(name)[1] == 'm') {
 169           *pp = p + (ct->size >> 1);
 170           return ct;
 171         }
 172       }
 173     } else if (cd->ctypeid == CTID_CTYPEID) {
 174       /* Allow indexing a (pointer to) struct constructor to get constants. */
 175       CType *sct = ctype_raw(cts, *(CTypeID *)p);
 176       if (ctype_isptr(sct->info))
 177         sct = ctype_rawchild(cts, sct);
 178       if (ctype_isstruct(sct->info)) {
 179         CTSize ofs;
 180         CType *fct = lj_ctype_getfield(cts, sct, name, &ofs);
 181         if (fct && ctype_isconstval(fct->info))
 182           return fct;
 183       }
 184       ct = sct;  /* Allow resolving metamethods for constructors, too. */
 185     }
 186   }
 187   if (ctype_isptr(ct->info)) {  /* Automatically perform '->'. */
 188     if (ctype_isstruct(ctype_rawchild(cts, ct)->info)) {
 189       p = (uint8_t *)cdata_getptr(p, ct->size);
 190       ct = ctype_child(cts, ct);
 191       goto collect_attrib;
 192     }
 193   }
 194   *qual |= 1;  /* Lookup failed. */
 195   return ct;  /* But return the resolved raw type. */
 196 }
 197
 198 /* -- C data getters ------------------------------------------------------ */
 199
 200 /* Get constant value and convert to TValue. */
 201 static void cdata_getconst(CTState *cts, TValue *o, CType *ct)
 202 {
 203   CType *ctt = ctype_child(cts, ct);
 204   lua_assert(ctype_isinteger(ctt->info) && ctt->size <= 4);
 205   /* Constants are already zero-extended/sign-extended to 32 bits. */
 206   if ((ctt->info & CTF_UNSIGNED) && (int32_t)ct->size < 0)
 207     setnumV(o, (lua_Number)(uint32_t)ct->size);
 208   else
 209     setintV(o, (int32_t)ct->size);
 210 }
 211
 212 /* Get C data value and convert to TValue. */
 213 int lj_cdata_get(CTState *cts, CType *s, TValue *o, uint8_t *sp)
 214 {
 215   CTypeID sid;
 216
 217   if (ctype_isconstval(s->info)) {
 218     cdata_getconst(cts, o, s);
 219     return 0;  /* No GC step needed. */
 220   } else if (ctype_isbitfield(s->info)) {
 221     return lj_cconv_tv_bf(cts, s, o, sp);
 222   }
 223
 224   /* Get child type of pointer/array/field. */
 225   lua_assert(ctype_ispointer(s->info) || ctype_isfield(s->info));
 226   sid = ctype_cid(s->info);
 227   s = ctype_get(cts, sid);
 228
 229   /* Resolve reference for field. */
 230   if (ctype_isref(s->info)) {
 231     lua_assert(s->size == CTSIZE_PTR);
 232     sp = *(uint8_t **)sp;
 233     sid = ctype_cid(s->info);
 234     s = ctype_get(cts, sid);
 235   }
 236
 237   /* Skip attributes. */
 238   while (ctype_isattrib(s->info))
 239     s = ctype_child(cts, s);
 240
 241   return lj_cconv_tv_ct(cts, s, sid, o, sp);
 242 }
 243
 244 /* -- C data setters ------------------------------------------------------ */
 245
 246 /* Convert TValue and set C data value. */
 247 void lj_cdata_set(CTState *cts, CType *d, uint8_t *dp, TValue *o, CTInfo qual)
 248 {
 249   if (ctype_isconstval(d->info)) {
 250     goto err_const;
 251   } else if (ctype_isbitfield(d->info)) {
 252     if (((d->info|qual) & CTF_CONST)) goto err_const;
 253     lj_cconv_bf_tv(cts, d, dp, o);
 254     return;
 255   }
 256
 257   /* Get child type of pointer/array/field. */
 258   lua_assert(ctype_ispointer(d->info) || ctype_isfield(d->info));
 259   d = ctype_child(cts, d);
 260
 261   /* Resolve reference for field. */
 262   if (ctype_isref(d->info)) {
 263     lua_assert(d->size == CTSIZE_PTR);
 264     dp = *(uint8_t **)dp;
 265     d = ctype_child(cts, d);
 266   }
 267
 268   /* Skip attributes and collect qualifiers. */
 269   for (;;) {
 270     if (ctype_isattrib(d->info)) {
 271       if (ctype_attrib(d->info) == CTA_QUAL) qual |= d->size;
 272     } else {
 273       break;
 274     }
 275     d = ctype_child(cts, d);
 276   }
 277
 278   lua_assert(ctype_hassize(d->info) && !ctype_isvoid(d->info));
 279
 280   if (((d->info|qual) & CTF_CONST)) {
 281   err_const:
 282     lj_err_caller(cts->L, LJ_ERR_FFI_WRCONST);
 283   }
 284
 285   lj_cconv_ct_tv(cts, d, dp, o, 0);
 286 }
 287
 288 #endif