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/*
** C data management.
** Copyright (C) 2005-2015 Mike Pall. See Copyright Notice in luajit.h
*/
#include "lj_obj.h"
#if LJ_HASFFI
#include "lj_gc.h"
#include "lj_err.h"
#include "lj_tab.h"
#include "lj_ctype.h"
#include "lj_cconv.h"
#include "lj_cdata.h"
/* -- C data allocation --------------------------------------------------- */
/* Allocate a new C data object holding a reference to another object. */
GCcdata *lj_cdata_newref(CTState *cts, const void *p, CTypeID id)
{
CTypeID refid = lj_ctype_intern(cts, CTINFO_REF(id), CTSIZE_PTR);
GCcdata *cd = lj_cdata_new(cts, refid, CTSIZE_PTR);
*(const void **)cdataptr(cd) = p;
return cd;
}
/* Allocate variable-sized or specially aligned C data object. */
GCcdata *lj_cdata_newv(lua_State *L, CTypeID id, CTSize sz, CTSize align)
{
global_State *g;
MSize extra = sizeof(GCcdataVar) + sizeof(GCcdata) +
(align > CT_MEMALIGN ? (1u<<align) - (1u<<CT_MEMALIGN) : 0);
char *p = lj_mem_newt(L, extra + sz, char);
uintptr_t adata = (uintptr_t)p + sizeof(GCcdataVar) + sizeof(GCcdata);
uintptr_t almask = (1u << align) - 1u;
GCcdata *cd = (GCcdata *)(((adata + almask) & ~almask) - sizeof(GCcdata));
lua_assert((char *)cd - p < 65536);
cdatav(cd)->offset = (uint16_t)((char *)cd - p);
cdatav(cd)->extra = extra;
cdatav(cd)->len = sz;
g = G(L);
setgcrefr(cd->nextgc, g->gc.root);
setgcref(g->gc.root, obj2gco(cd));
newwhite(g, obj2gco(cd));
cd->marked |= 0x80;
cd->gct = ~LJ_TCDATA;
cd->ctypeid = id;
return cd;
}
/* Free a C data object. */
void LJ_FASTCALL lj_cdata_free(global_State *g, GCcdata *cd)
{
if (LJ_UNLIKELY(cd->marked & LJ_GC_CDATA_FIN)) {
GCobj *root;
makewhite(g, obj2gco(cd));
markfinalized(obj2gco(cd));
if ((root = gcref(g->gc.mmudata)) != NULL) {
setgcrefr(cd->nextgc, root->gch.nextgc);
setgcref(root->gch.nextgc, obj2gco(cd));
setgcref(g->gc.mmudata, obj2gco(cd));
} else {
setgcref(cd->nextgc, obj2gco(cd));
setgcref(g->gc.mmudata, obj2gco(cd));
}
} else if (LJ_LIKELY(!cdataisv(cd))) {
CType *ct = ctype_raw(ctype_ctsG(g), cd->ctypeid);
CTSize sz = ctype_hassize(ct->info) ? ct->size : CTSIZE_PTR;
lua_assert(ctype_hassize(ct->info) || ctype_isfunc(ct->info) ||
ctype_isextern(ct->info));
lj_mem_free(g, cd, sizeof(GCcdata) + sz);
} else {
lj_mem_free(g, memcdatav(cd), sizecdatav(cd));
}
}
void lj_cdata_setfin(lua_State *L, GCcdata *cd, GCobj *obj, uint32_t it)
{
GCtab *t = ctype_ctsG(G(L))->finalizer;
if (gcref(t->metatable)) {
/* Add cdata to finalizer table, if still enabled. */
TValue *tv, tmp;
setcdataV(L, &tmp, cd);
lj_gc_anybarriert(L, t);
tv = lj_tab_set(L, t, &tmp);
setgcV(L, tv, obj, it);
if (!tvisnil(tv))
cd->marked |= LJ_GC_CDATA_FIN;
else
cd->marked &= ~LJ_GC_CDATA_FIN;
}
}
/* -- C data indexing ----------------------------------------------------- */
/* Index C data by a TValue. Return CType and pointer. */
CType *lj_cdata_index(CTState *cts, GCcdata *cd, cTValue *key, uint8_t **pp,
CTInfo *qual)
{
uint8_t *p = (uint8_t *)cdataptr(cd);
CType *ct = ctype_get(cts, cd->ctypeid);
ptrdiff_t idx;
/* Resolve reference for cdata object. */
if (ctype_isref(ct->info)) {
lua_assert(ct->size == CTSIZE_PTR);
p = *(uint8_t **)p;
ct = ctype_child(cts, ct);
}
collect_attrib:
/* Skip attributes and collect qualifiers. */
while (ctype_isattrib(ct->info)) {
if (ctype_attrib(ct->info) == CTA_QUAL) *qual |= ct->size;
ct = ctype_child(cts, ct);
}
lua_assert(!ctype_isref(ct->info)); /* Interning rejects refs to refs. */
if (tvisint(key)) {
idx = (ptrdiff_t)intV(key);
goto integer_key;
} else if (tvisnum(key)) { /* Numeric key. */
#ifdef _MSC_VER
/* Workaround for MSVC bug. */
volatile
#endif
lua_Number n = numV(key);
idx = LJ_64 ? (ptrdiff_t)n : (ptrdiff_t)lj_num2int(n);
integer_key:
if (ctype_ispointer(ct->info)) {
CTSize sz = lj_ctype_size(cts, ctype_cid(ct->info)); /* Element size. */
if (sz == CTSIZE_INVALID)
lj_err_caller(cts->L, LJ_ERR_FFI_INVSIZE);
if (ctype_isptr(ct->info)) {
p = (uint8_t *)cdata_getptr(p, ct->size);
} else if ((ct->info & (CTF_VECTOR|CTF_COMPLEX))) {
if ((ct->info & CTF_COMPLEX)) idx &= 1;
*qual |= CTF_CONST; /* Valarray elements are constant. */
}
*pp = p + idx*(int32_t)sz;
return ct;
}
} else if (tviscdata(key)) { /* Integer cdata key. */
GCcdata *cdk = cdataV(key);
CType *ctk = ctype_raw(cts, cdk->ctypeid);
if (ctype_isenum(ctk->info)) ctk = ctype_child(cts, ctk);
if (ctype_isinteger(ctk->info)) {
lj_cconv_ct_ct(cts, ctype_get(cts, CTID_INT_PSZ), ctk,
(uint8_t *)&idx, cdataptr(cdk), 0);
goto integer_key;
}
} else if (tvisstr(key)) { /* String key. */
GCstr *name = strV(key);
if (ctype_isstruct(ct->info)) {
CTSize ofs;
CType *fct = lj_ctype_getfieldq(cts, ct, name, &ofs, qual);
if (fct) {
*pp = p + ofs;
return fct;
}
} else if (ctype_iscomplex(ct->info)) {
if (name->len == 2) {
*qual |= CTF_CONST; /* Complex fields are constant. */
if (strdata(name)[0] == 'r' && strdata(name)[1] == 'e') {
*pp = p;
return ct;
} else if (strdata(name)[0] == 'i' && strdata(name)[1] == 'm') {
*pp = p + (ct->size >> 1);
return ct;
}
}
} else if (cd->ctypeid == CTID_CTYPEID) {
/* Allow indexing a (pointer to) struct constructor to get constants. */
CType *sct = ctype_raw(cts, *(CTypeID *)p);
if (ctype_isptr(sct->info))
sct = ctype_rawchild(cts, sct);
if (ctype_isstruct(sct->info)) {
CTSize ofs;
CType *fct = lj_ctype_getfield(cts, sct, name, &ofs);
if (fct && ctype_isconstval(fct->info))
return fct;
}
ct = sct; /* Allow resolving metamethods for constructors, too. */
}
}
if (ctype_isptr(ct->info)) { /* Automatically perform '->'. */
if (ctype_isstruct(ctype_rawchild(cts, ct)->info)) {
p = (uint8_t *)cdata_getptr(p, ct->size);
ct = ctype_child(cts, ct);
goto collect_attrib;
}
}
*qual |= 1; /* Lookup failed. */
return ct; /* But return the resolved raw type. */
}
/* -- C data getters ------------------------------------------------------ */
/* Get constant value and convert to TValue. */
static void cdata_getconst(CTState *cts, TValue *o, CType *ct)
{
CType *ctt = ctype_child(cts, ct);
lua_assert(ctype_isinteger(ctt->info) && ctt->size <= 4);
/* Constants are already zero-extended/sign-extended to 32 bits. */
if ((ctt->info & CTF_UNSIGNED) && (int32_t)ct->size < 0)
setnumV(o, (lua_Number)(uint32_t)ct->size);
else
setintV(o, (int32_t)ct->size);
}
/* Get C data value and convert to TValue. */
int lj_cdata_get(CTState *cts, CType *s, TValue *o, uint8_t *sp)
{
CTypeID sid;
if (ctype_isconstval(s->info)) {
cdata_getconst(cts, o, s);
return 0; /* No GC step needed. */
} else if (ctype_isbitfield(s->info)) {
return lj_cconv_tv_bf(cts, s, o, sp);
}
/* Get child type of pointer/array/field. */
lua_assert(ctype_ispointer(s->info) || ctype_isfield(s->info));
sid = ctype_cid(s->info);
s = ctype_get(cts, sid);
/* Resolve reference for field. */
if (ctype_isref(s->info)) {
lua_assert(s->size == CTSIZE_PTR);
sp = *(uint8_t **)sp;
sid = ctype_cid(s->info);
s = ctype_get(cts, sid);
}
/* Skip attributes. */
while (ctype_isattrib(s->info))
s = ctype_child(cts, s);
return lj_cconv_tv_ct(cts, s, sid, o, sp);
}
/* -- C data setters ------------------------------------------------------ */
/* Convert TValue and set C data value. */
void lj_cdata_set(CTState *cts, CType *d, uint8_t *dp, TValue *o, CTInfo qual)
{
if (ctype_isconstval(d->info)) {
goto err_const;
} else if (ctype_isbitfield(d->info)) {
if (((d->info|qual) & CTF_CONST)) goto err_const;
lj_cconv_bf_tv(cts, d, dp, o);
return;
}
/* Get child type of pointer/array/field. */
lua_assert(ctype_ispointer(d->info) || ctype_isfield(d->info));
d = ctype_child(cts, d);
/* Resolve reference for field. */
if (ctype_isref(d->info)) {
lua_assert(d->size == CTSIZE_PTR);
dp = *(uint8_t **)dp;
d = ctype_child(cts, d);
}
/* Skip attributes and collect qualifiers. */
for (;;) {
if (ctype_isattrib(d->info)) {
if (ctype_attrib(d->info) == CTA_QUAL) qual |= d->size;
} else {
break;
}
d = ctype_child(cts, d);
}
lua_assert(ctype_hassize(d->info) && !ctype_isvoid(d->info));
if (((d->info|qual) & CTF_CONST)) {
err_const:
lj_err_caller(cts->L, LJ_ERR_FFI_WRCONST);
}
lj_cconv_ct_tv(cts, d, dp, o, 0);
}
#endif
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