mirror of
https://github.com/LuaJIT/LuaJIT.git
synced 2025-02-07 23:24:09 +00:00
FFI: Add pointer arithmetic.
This commit is contained in:
Mike Pall
parent
ba20871f0f
commit
79ab1a4baa
110
src/lib_ffi.c
110
src/lib_ffi.c
@ -74,6 +74,41 @@ static void *ffi_checkptr(lua_State *L, int narg, CTypeID id)
|
||||
return p;
|
||||
}
|
||||
|
||||
typedef struct FFIArith {
|
||||
uint8_t *p[2];
|
||||
CType *ct[2];
|
||||
} FFIArith;
|
||||
|
||||
/* Check arguments for arithmetic metamethods. */
|
||||
static void ffi_checkarith(lua_State *L, FFIArith *fa)
|
||||
{
|
||||
CTState *cts = ctype_cts(L);
|
||||
TValue *o = L->base;
|
||||
MSize i;
|
||||
if (o+1 >= L->top)
|
||||
lj_err_argt(L, 1, LUA_TCDATA);
|
||||
for (i = 0; i < 2; i++, o++) {
|
||||
if (tviscdata(o)) {
|
||||
GCcdata *cd = cdataV(o);
|
||||
CTypeID id = (CTypeID)cd->typeid;
|
||||
CType *ct = ctype_get(cts, id);
|
||||
uint8_t *p = (uint8_t *)cdataptr(cd);
|
||||
if (ctype_isref(ct->info)) {
|
||||
lua_assert(ct->size == CTSIZE_PTR);
|
||||
p = *(uint8_t **)p;
|
||||
id = ctype_cid(ct->info);
|
||||
}
|
||||
fa->ct[i] = ctype_raw(cts, id);
|
||||
fa->p[i] = p;
|
||||
} else if (tvisnum(o)) {
|
||||
fa->ct[i] = ctype_get(cts, CTID_DOUBLE);
|
||||
fa->p[i] = (uint8_t *)&o->n;
|
||||
} else {
|
||||
lj_err_optype(L, o, LJ_ERR_OPARITH);
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
/* -- C type metamethods -------------------------------------------------- */
|
||||
|
||||
#define LJLIB_MODULE_ffi_meta
|
||||
@ -118,6 +153,81 @@ LJLIB_CF(ffi_meta___call) LJLIB_REC(cdata_call)
|
||||
return 0; /* unreachable */
|
||||
}
|
||||
|
||||
/* Pointer arithmetic. */
|
||||
static int ffi_arith_ptr(lua_State *L, FFIArith *fa, int sub)
|
||||
{
|
||||
CTState *cts = ctype_cts(L);
|
||||
CType *ctp = fa->ct[0];
|
||||
uint8_t *pp = fa->p[0];
|
||||
ptrdiff_t idx;
|
||||
CTSize sz;
|
||||
CTypeID id;
|
||||
GCcdata *cd;
|
||||
if (ctype_isptr(ctp->info) || ctype_isrefarray(ctp->info)) {
|
||||
if (sub &&
|
||||
(ctype_isptr(fa->ct[1]->info) || ctype_isrefarray(fa->ct[1]->info))) {
|
||||
/* Pointer difference. */
|
||||
intptr_t diff;
|
||||
if (!lj_cconv_compatptr(cts, ctp, fa->ct[1], CCF_IGNQUAL))
|
||||
lj_err_caller(L, LJ_ERR_FFI_INVTYPE);
|
||||
sz = lj_ctype_size(cts, ctype_cid(ctp->info)); /* Element size. */
|
||||
if (sz == 0 || sz == CTSIZE_INVALID)
|
||||
lj_err_caller(L, LJ_ERR_FFI_INVSIZE);
|
||||
if (ctype_isptr(ctp->info))
|
||||
pp = (uint8_t *)cdata_getptr(pp, ctp->size);
|
||||
if (ctype_isptr(fa->ct[1]->info))
|
||||
fa->p[1] = (uint8_t *)cdata_getptr(fa->p[1], fa->ct[1]->size);
|
||||
diff = ((intptr_t)pp - (intptr_t)fa->p[1]) / (int32_t)sz;
|
||||
/* All valid pointer differences on x64 are in (-2^47, +2^47),
|
||||
** which fits into a double without loss of precision.
|
||||
*/
|
||||
setnumV(L->top-1, (lua_Number)diff);
|
||||
return 1;
|
||||
}
|
||||
lj_cconv_ct_ct(cts, ctype_get(cts, CTID_INT_PSZ), fa->ct[1],
|
||||
(uint8_t *)&idx, fa->p[1], 0);
|
||||
if (sub) idx = -idx;
|
||||
} else if (!sub &&
|
||||
(ctype_isptr(fa->ct[1]->info) || ctype_isrefarray(fa->ct[1]->info))) {
|
||||
/* Swap pointer and index. */
|
||||
ctp = fa->ct[1]; pp = fa->p[1];
|
||||
lj_cconv_ct_ct(cts, ctype_get(cts, CTID_INT_PSZ), fa->ct[0],
|
||||
(uint8_t *)&idx, fa->p[0], 0);
|
||||
} else {
|
||||
return 0;
|
||||
}
|
||||
sz = lj_ctype_size(cts, ctype_cid(ctp->info)); /* Element size. */
|
||||
if (sz == CTSIZE_INVALID)
|
||||
lj_err_caller(L, LJ_ERR_FFI_INVSIZE);
|
||||
if (ctype_isptr(ctp->info))
|
||||
pp = (uint8_t *)cdata_getptr(pp, ctp->size);
|
||||
pp += idx*(int32_t)sz; /* Compute pointer + index. */
|
||||
id = lj_ctype_intern(cts, CTINFO(CT_PTR, CTALIGN_PTR|ctype_cid(ctp->info)),
|
||||
CTSIZE_PTR);
|
||||
cd = lj_cdata_new(cts, id, CTSIZE_PTR);
|
||||
*(uint8_t **)cdataptr(cd) = pp;
|
||||
setcdataV(L, L->top-1, cd);
|
||||
return 1;
|
||||
}
|
||||
|
||||
LJLIB_CF(ffi_meta___add)
|
||||
{
|
||||
FFIArith fa;
|
||||
ffi_checkarith(L, &fa);
|
||||
if (!ffi_arith_ptr(L, &fa, 0))
|
||||
lj_err_caller(L, LJ_ERR_FFI_INVTYPE);
|
||||
return 1;
|
||||
}
|
||||
|
||||
LJLIB_CF(ffi_meta___sub)
|
||||
{
|
||||
FFIArith fa;
|
||||
ffi_checkarith(L, &fa);
|
||||
if (!ffi_arith_ptr(L, &fa, 1))
|
||||
lj_err_caller(L, LJ_ERR_FFI_INVTYPE);
|
||||
return 1;
|
||||
}
|
||||
|
||||
LJLIB_CF(ffi_meta___tostring)
|
||||
{
|
||||
GCcdata *cd = ffi_checkcdata(L, 1);
|
||||
|
||||
@ -63,7 +63,7 @@ static CType *cconv_childqual(CTState *cts, CType *ct, CTInfo *qual)
|
||||
/* Check for compatible types when converting to a pointer.
|
||||
** Note: these checks are more relaxed than what C99 mandates.
|
||||
*/
|
||||
static int cconv_compatptr(CTState *cts, CType *d, CType *s, CTInfo flags)
|
||||
int lj_cconv_compatptr(CTState *cts, CType *d, CType *s, CTInfo flags)
|
||||
{
|
||||
if (!((flags & CCF_CAST) || d == s)) {
|
||||
CTInfo dqual = 0, squal = 0;
|
||||
@ -73,7 +73,7 @@ static int cconv_compatptr(CTState *cts, CType *d, CType *s, CTInfo flags)
|
||||
if ((flags & CCF_SAME)) {
|
||||
if (dqual != squal)
|
||||
return 0; /* Different qualifiers. */
|
||||
} else {
|
||||
} else if (!(flags & CCF_IGNQUAL)) {
|
||||
if ((dqual & squal) != squal)
|
||||
return 0; /* Discarded qualifiers. */
|
||||
if (ctype_isvoid(d->info) || ctype_isvoid(s->info))
|
||||
@ -87,7 +87,7 @@ static int cconv_compatptr(CTState *cts, CType *d, CType *s, CTInfo flags)
|
||||
return 0; /* Different numeric types. */
|
||||
} else if (ctype_ispointer(d->info)) {
|
||||
/* Check child types for compatibility. */
|
||||
return cconv_compatptr(cts, d, s, flags|CCF_SAME);
|
||||
return lj_cconv_compatptr(cts, d, s, flags|CCF_SAME);
|
||||
} else if (ctype_isstruct(d->info)) {
|
||||
if (d != s)
|
||||
return 0; /* Must be exact same type for struct/union. */
|
||||
@ -339,20 +339,20 @@ void lj_cconv_ct_ct(CTState *cts, CType *d, CType *s,
|
||||
goto conv_I_F;
|
||||
|
||||
case CCX(P, P):
|
||||
if (!cconv_compatptr(cts, d, s, flags)) goto err_conv;
|
||||
if (!lj_cconv_compatptr(cts, d, s, flags)) goto err_conv;
|
||||
cdata_setptr(dp, dsize, cdata_getptr(sp, ssize));
|
||||
break;
|
||||
|
||||
case CCX(P, A):
|
||||
case CCX(P, S):
|
||||
if (!cconv_compatptr(cts, d, s, flags)) goto err_conv;
|
||||
if (!lj_cconv_compatptr(cts, d, s, flags)) goto err_conv;
|
||||
cdata_setptr(dp, dsize, sp);
|
||||
break;
|
||||
|
||||
/* Destination is an array. */
|
||||
case CCX(A, A):
|
||||
if ((flags & CCF_CAST) || (d->info & CTF_VLA) || d->size != s->size ||
|
||||
d->size == CTSIZE_INVALID || !cconv_compatptr(cts, d, s, flags))
|
||||
d->size == CTSIZE_INVALID || !lj_cconv_compatptr(cts, d, s, flags))
|
||||
goto err_conv;
|
||||
goto copyval;
|
||||
|
||||
|
||||
@ -46,8 +46,10 @@ static LJ_AINLINE uint32_t cconv_idx(CTInfo info)
|
||||
#define CCF_CAST 0x00000001u
|
||||
#define CCF_FROMTV 0x00000002u
|
||||
#define CCF_SAME 0x00000004u
|
||||
#define CCF_IGNQUAL 0x00000008u
|
||||
|
||||
|
||||
LJ_FUNC int lj_cconv_compatptr(CTState *cts, CType *d, CType *s, CTInfo flags);
|
||||
LJ_FUNC void lj_cconv_ct_ct(CTState *cts, CType *d, CType *s,
|
||||
uint8_t *dp, uint8_t *sp, CTInfo flags);
|
||||
LJ_FUNC void lj_cconv_tv_ct(CTState *cts, CType *s, CTypeID sid,
|
||||
|
||||
Loading…
Reference in New Issue
Block a user