1/*
2** C data arithmetic.
3** Copyright (C) 2005-2021 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_meta.h"
14#include "lj_ir.h"
15#include "lj_ctype.h"
16#include "lj_cconv.h"
17#include "lj_cdata.h"
18#include "lj_carith.h"
19#include "lj_strscan.h"
20
21/* -- C data arithmetic --------------------------------------------------- */
22
23/* Binary operands of an operator converted to ctypes. */
24typedef struct CDArith {
25 uint8_t *p[2];
26 CType *ct[2];
27} CDArith;
28
29/* Check arguments for arithmetic metamethods. */
30static int carith_checkarg(lua_State *L, CTState *cts, CDArith *ca)
31{
32 TValue *o = L->base;
33 int ok = 1;
34 MSize i;
35 if (o+1 >= L->top)
36 lj_err_argt(L, 1, LUA_TCDATA);
37 for (i = 0; i < 2; i++, o++) {
38 if (tviscdata(o)) {
39 GCcdata *cd = cdataV(o);
40 CTypeID id = (CTypeID)cd->ctypeid;
41 CType *ct = ctype_raw(cts, id);
42 uint8_t *p = (uint8_t *)cdataptr(cd);
43 if (ctype_isptr(ct->info)) {
44 p = (uint8_t *)cdata_getptr(p, ct->size);
45 if (ctype_isref(ct->info)) ct = ctype_rawchild(cts, ct);
46 } else if (ctype_isfunc(ct->info)) {
47 p = (uint8_t *)*(void **)p;
48 ct = ctype_get(cts,
49 lj_ctype_intern(cts, CTINFO(CT_PTR, CTALIGN_PTR|id), CTSIZE_PTR));
50 }
51 if (ctype_isenum(ct->info)) ct = ctype_child(cts, ct);
52 ca->ct[i] = ct;
53 ca->p[i] = p;
54 } else if (tvisint(o)) {
55 ca->ct[i] = ctype_get(cts, CTID_INT32);
56 ca->p[i] = (uint8_t *)&o->i;
57 } else if (tvisnum(o)) {
58 ca->ct[i] = ctype_get(cts, CTID_DOUBLE);
59 ca->p[i] = (uint8_t *)&o->n;
60 } else if (tvisnil(o)) {
61 ca->ct[i] = ctype_get(cts, CTID_P_VOID);
62 ca->p[i] = (uint8_t *)0;
63 } else if (tvisstr(o)) {
64 TValue *o2 = i == 0 ? o+1 : o-1;
65 CType *ct = ctype_raw(cts, cdataV(o2)->ctypeid);
66 ca->ct[i] = NULL;
67 ca->p[i] = (uint8_t *)strVdata(o);
68 ok = 0;
69 if (ctype_isenum(ct->info)) {
70 CTSize ofs;
71 CType *cct = lj_ctype_getfield(cts, ct, strV(o), &ofs);
72 if (cct && ctype_isconstval(cct->info)) {
73 ca->ct[i] = ctype_child(cts, cct);
74 ca->p[i] = (uint8_t *)&cct->size; /* Assumes ct does not grow. */
75 ok = 1;
76 } else {
77 ca->ct[1-i] = ct; /* Use enum to improve error message. */
78 ca->p[1-i] = NULL;
79 break;
80 }
81 }
82 } else {
83 ca->ct[i] = NULL;
84 ca->p[i] = (void *)(intptr_t)1; /* To make it unequal. */
85 ok = 0;
86 }
87 }
88 return ok;
89}
90
91/* Pointer arithmetic. */
92static int carith_ptr(lua_State *L, CTState *cts, CDArith *ca, MMS mm)
93{
94 CType *ctp = ca->ct[0];
95 uint8_t *pp = ca->p[0];
96 ptrdiff_t idx;
97 CTSize sz;
98 CTypeID id;
99 GCcdata *cd;
100 if (ctype_isptr(ctp->info) || ctype_isrefarray(ctp->info)) {
101 if ((mm == MM_sub || mm == MM_eq || mm == MM_lt || mm == MM_le) &&
102 (ctype_isptr(ca->ct[1]->info) || ctype_isrefarray(ca->ct[1]->info))) {
103 uint8_t *pp2 = ca->p[1];
104 if (mm == MM_eq) { /* Pointer equality. Incompatible pointers are ok. */
105 setboolV(L->top-1, (pp == pp2));
106 return 1;
107 }
108 if (!lj_cconv_compatptr(cts, ctp, ca->ct[1], CCF_IGNQUAL))
109 return 0;
110 if (mm == MM_sub) { /* Pointer difference. */
111 intptr_t diff;
112 sz = lj_ctype_size(cts, ctype_cid(ctp->info)); /* Element size. */
113 if (sz == 0 || sz == CTSIZE_INVALID)
114 return 0;
115 diff = ((intptr_t)pp - (intptr_t)pp2) / (int32_t)sz;
116 /* All valid pointer differences on x64 are in (-2^47, +2^47),
117 ** which fits into a double without loss of precision.
118 */
119 setintptrV(L->top-1, (int32_t)diff);
120 return 1;
121 } else if (mm == MM_lt) { /* Pointer comparison (unsigned). */
122 setboolV(L->top-1, ((uintptr_t)pp < (uintptr_t)pp2));
123 return 1;
124 } else {
125 lj_assertL(mm == MM_le, "bad metamethod %d", mm);
126 setboolV(L->top-1, ((uintptr_t)pp <= (uintptr_t)pp2));
127 return 1;
128 }
129 }
130 if (!((mm == MM_add || mm == MM_sub) && ctype_isnum(ca->ct[1]->info)))
131 return 0;
132 lj_cconv_ct_ct(cts, ctype_get(cts, CTID_INT_PSZ), ca->ct[1],
133 (uint8_t *)&idx, ca->p[1], 0);
134 if (mm == MM_sub) idx = -idx;
135 } else if (mm == MM_add && ctype_isnum(ctp->info) &&
136 (ctype_isptr(ca->ct[1]->info) || ctype_isrefarray(ca->ct[1]->info))) {
137 /* Swap pointer and index. */
138 ctp = ca->ct[1]; pp = ca->p[1];
139 lj_cconv_ct_ct(cts, ctype_get(cts, CTID_INT_PSZ), ca->ct[0],
140 (uint8_t *)&idx, ca->p[0], 0);
141 } else {
142 return 0;
143 }
144 sz = lj_ctype_size(cts, ctype_cid(ctp->info)); /* Element size. */
145 if (sz == CTSIZE_INVALID)
146 return 0;
147 pp += idx*(int32_t)sz; /* Compute pointer + index. */
148 id = lj_ctype_intern(cts, CTINFO(CT_PTR, CTALIGN_PTR|ctype_cid(ctp->info)),
149 CTSIZE_PTR);
150 cd = lj_cdata_new(cts, id, CTSIZE_PTR);
151 *(uint8_t **)cdataptr(cd) = pp;
152 setcdataV(L, L->top-1, cd);
153 lj_gc_check(L);
154 return 1;
155}
156
157/* 64 bit integer arithmetic. */
158static int carith_int64(lua_State *L, CTState *cts, CDArith *ca, MMS mm)
159{
160 if (ctype_isnum(ca->ct[0]->info) && ca->ct[0]->size <= 8 &&
161 ctype_isnum(ca->ct[1]->info) && ca->ct[1]->size <= 8) {
162 CTypeID id = (((ca->ct[0]->info & CTF_UNSIGNED) && ca->ct[0]->size == 8) ||
163 ((ca->ct[1]->info & CTF_UNSIGNED) && ca->ct[1]->size == 8)) ?
164 CTID_UINT64 : CTID_INT64;
165 CType *ct = ctype_get(cts, id);
166 GCcdata *cd;
167 uint64_t u0, u1, *up;
168 lj_cconv_ct_ct(cts, ct, ca->ct[0], (uint8_t *)&u0, ca->p[0], 0);
169 if (mm != MM_unm)
170 lj_cconv_ct_ct(cts, ct, ca->ct[1], (uint8_t *)&u1, ca->p[1], 0);
171 switch (mm) {
172 case MM_eq:
173 setboolV(L->top-1, (u0 == u1));
174 return 1;
175 case MM_lt:
176 setboolV(L->top-1,
177 id == CTID_INT64 ? ((int64_t)u0 < (int64_t)u1) : (u0 < u1));
178 return 1;
179 case MM_le:
180 setboolV(L->top-1,
181 id == CTID_INT64 ? ((int64_t)u0 <= (int64_t)u1) : (u0 <= u1));
182 return 1;
183 default: break;
184 }
185 cd = lj_cdata_new(cts, id, 8);
186 up = (uint64_t *)cdataptr(cd);
187 setcdataV(L, L->top-1, cd);
188 switch (mm) {
189 case MM_add: *up = u0 + u1; break;
190 case MM_sub: *up = u0 - u1; break;
191 case MM_mul: *up = u0 * u1; break;
192 case MM_div:
193 if (id == CTID_INT64)
194 *up = (uint64_t)lj_carith_divi64((int64_t)u0, (int64_t)u1);
195 else
196 *up = lj_carith_divu64(u0, u1);
197 break;
198 case MM_mod:
199 if (id == CTID_INT64)
200 *up = (uint64_t)lj_carith_modi64((int64_t)u0, (int64_t)u1);
201 else
202 *up = lj_carith_modu64(u0, u1);
203 break;
204 case MM_pow:
205 if (id == CTID_INT64)
206 *up = (uint64_t)lj_carith_powi64((int64_t)u0, (int64_t)u1);
207 else
208 *up = lj_carith_powu64(u0, u1);
209 break;
210 case MM_unm: *up = (uint64_t)-(int64_t)u0; break;
211 default:
212 lj_assertL(0, "bad metamethod %d", mm);
213 break;
214 }
215 lj_gc_check(L);
216 return 1;
217 }
218 return 0;
219}
220
221/* Handle ctype arithmetic metamethods. */
222static int lj_carith_meta(lua_State *L, CTState *cts, CDArith *ca, MMS mm)
223{
224 cTValue *tv = NULL;
225 if (tviscdata(L->base)) {
226 CTypeID id = cdataV(L->base)->ctypeid;
227 CType *ct = ctype_raw(cts, id);
228 if (ctype_isptr(ct->info)) id = ctype_cid(ct->info);
229 tv = lj_ctype_meta(cts, id, mm);
230 }
231 if (!tv && L->base+1 < L->top && tviscdata(L->base+1)) {
232 CTypeID id = cdataV(L->base+1)->ctypeid;
233 CType *ct = ctype_raw(cts, id);
234 if (ctype_isptr(ct->info)) id = ctype_cid(ct->info);
235 tv = lj_ctype_meta(cts, id, mm);
236 }
237 if (!tv) {
238 const char *repr[2];
239 int i, isenum = -1, isstr = -1;
240 if (mm == MM_eq) { /* Equality checks never raise an error. */
241 int eq = ca->p[0] == ca->p[1];
242 setboolV(L->top-1, eq);
243 setboolV(&G(L)->tmptv2, eq); /* Remember for trace recorder. */
244 return 1;
245 }
246 for (i = 0; i < 2; i++) {
247 if (ca->ct[i] && tviscdata(L->base+i)) {
248 if (ctype_isenum(ca->ct[i]->info)) isenum = i;
249 repr[i] = strdata(lj_ctype_repr(L, ctype_typeid(cts, ca->ct[i]), NULL));
250 } else {
251 if (tvisstr(&L->base[i])) isstr = i;
252 repr[i] = lj_typename(&L->base[i]);
253 }
254 }
255 if ((isenum ^ isstr) == 1)
256 lj_err_callerv(L, LJ_ERR_FFI_BADCONV, repr[isstr], repr[isenum]);
257 lj_err_callerv(L, mm == MM_len ? LJ_ERR_FFI_BADLEN :
258 mm == MM_concat ? LJ_ERR_FFI_BADCONCAT :
259 mm < MM_add ? LJ_ERR_FFI_BADCOMP : LJ_ERR_FFI_BADARITH,
260 repr[0], repr[1]);
261 }
262 return lj_meta_tailcall(L, tv);
263}
264
265/* Arithmetic operators for cdata. */
266int lj_carith_op(lua_State *L, MMS mm)
267{
268 CTState *cts = ctype_cts(L);
269 CDArith ca;
270 if (carith_checkarg(L, cts, &ca) && mm != MM_len && mm != MM_concat) {
271 if (carith_int64(L, cts, &ca, mm) || carith_ptr(L, cts, &ca, mm)) {
272 copyTV(L, &G(L)->tmptv2, L->top-1); /* Remember for trace recorder. */
273 return 1;
274 }
275 }
276 return lj_carith_meta(L, cts, &ca, mm);
277}
278
279/* -- 64 bit bit operations helpers --------------------------------------- */
280
281#if LJ_64
282#define B64DEF(name) \
283 static LJ_AINLINE uint64_t lj_carith_##name(uint64_t x, int32_t sh)
284#else
285/* Not inlined on 32 bit archs, since some of these are quite lengthy. */
286#define B64DEF(name) \
287 uint64_t LJ_NOINLINE lj_carith_##name(uint64_t x, int32_t sh)
288#endif
289
290B64DEF(shl64) { return x << (sh&63); }
291B64DEF(shr64) { return x >> (sh&63); }
292B64DEF(sar64) { return (uint64_t)((int64_t)x >> (sh&63)); }
293B64DEF(rol64) { return lj_rol(x, (sh&63)); }
294B64DEF(ror64) { return lj_ror(x, (sh&63)); }
295
296#undef B64DEF
297
298uint64_t lj_carith_shift64(uint64_t x, int32_t sh, int op)
299{
300 switch (op) {
301 case IR_BSHL-IR_BSHL: x = lj_carith_shl64(x, sh); break;
302 case IR_BSHR-IR_BSHL: x = lj_carith_shr64(x, sh); break;
303 case IR_BSAR-IR_BSHL: x = lj_carith_sar64(x, sh); break;
304 case IR_BROL-IR_BSHL: x = lj_carith_rol64(x, sh); break;
305 case IR_BROR-IR_BSHL: x = lj_carith_ror64(x, sh); break;
306 default:
307 lj_assertX(0, "bad shift op %d", op);
308 break;
309 }
310 return x;
311}
312
313/* Equivalent to lj_lib_checkbit(), but handles cdata. */
314uint64_t lj_carith_check64(lua_State *L, int narg, CTypeID *id)
315{
316 TValue *o = L->base + narg-1;
317 if (o >= L->top) {
318 err:
319 lj_err_argt(L, narg, LUA_TNUMBER);
320 } else if (LJ_LIKELY(tvisnumber(o))) {
321 /* Handled below. */
322 } else if (tviscdata(o)) {
323 CTState *cts = ctype_cts(L);
324 uint8_t *sp = (uint8_t *)cdataptr(cdataV(o));
325 CTypeID sid = cdataV(o)->ctypeid;
326 CType *s = ctype_get(cts, sid);
327 uint64_t x;
328 if (ctype_isref(s->info)) {
329 sp = *(void **)sp;
330 sid = ctype_cid(s->info);
331 }
332 s = ctype_raw(cts, sid);
333 if (ctype_isenum(s->info)) s = ctype_child(cts, s);
334 if ((s->info & (CTMASK_NUM|CTF_BOOL|CTF_FP|CTF_UNSIGNED)) ==
335 CTINFO(CT_NUM, CTF_UNSIGNED) && s->size == 8)
336 *id = CTID_UINT64; /* Use uint64_t, since it has the highest rank. */
337 else if (!*id)
338 *id = CTID_INT64; /* Use int64_t, unless already set. */
339 lj_cconv_ct_ct(cts, ctype_get(cts, *id), s,
340 (uint8_t *)&x, sp, CCF_ARG(narg));
341 return x;
342 } else if (!(tvisstr(o) && lj_strscan_number(strV(o), o))) {
343 goto err;
344 }
345 if (LJ_LIKELY(tvisint(o))) {
346 return (uint32_t)intV(o);
347 } else {
348 int32_t i = lj_num2bit(numV(o));
349 if (LJ_DUALNUM) setintV(o, i);
350 return (uint32_t)i;
351 }
352}
353
354/* -- 64 bit integer arithmetic helpers ----------------------------------- */
355
356#if LJ_32 && LJ_HASJIT
357/* Signed/unsigned 64 bit multiplication. */
358int64_t lj_carith_mul64(int64_t a, int64_t b)
359{
360 return a * b;
361}
362#endif
363
364/* Unsigned 64 bit division. */
365uint64_t lj_carith_divu64(uint64_t a, uint64_t b)
366{
367 if (b == 0) return U64x(80000000,00000000);
368 return a / b;
369}
370
371/* Signed 64 bit division. */
372int64_t lj_carith_divi64(int64_t a, int64_t b)
373{
374 if (b == 0 || (a == (int64_t)U64x(80000000,00000000) && b == -1))
375 return U64x(80000000,00000000);
376 return a / b;
377}
378
379/* Unsigned 64 bit modulo. */
380uint64_t lj_carith_modu64(uint64_t a, uint64_t b)
381{
382 if (b == 0) return U64x(80000000,00000000);
383 return a % b;
384}
385
386/* Signed 64 bit modulo. */
387int64_t lj_carith_modi64(int64_t a, int64_t b)
388{
389 if (b == 0) return U64x(80000000,00000000);
390 if (a == (int64_t)U64x(80000000,00000000) && b == -1) return 0;
391 return a % b;
392}
393
394/* Unsigned 64 bit x^k. */
395uint64_t lj_carith_powu64(uint64_t x, uint64_t k)
396{
397 uint64_t y;
398 if (k == 0)
399 return 1;
400 for (; (k & 1) == 0; k >>= 1) x *= x;
401 y = x;
402 if ((k >>= 1) != 0) {
403 for (;;) {
404 x *= x;
405 if (k == 1) break;
406 if (k & 1) y *= x;
407 k >>= 1;
408 }
409 y *= x;
410 }
411 return y;
412}
413
414/* Signed 64 bit x^k. */
415int64_t lj_carith_powi64(int64_t x, int64_t k)
416{
417 if (k == 0)
418 return 1;
419 if (k < 0) {
420 if (x == 0)
421 return U64x(7fffffff,ffffffff);
422 else if (x == 1)
423 return 1;
424 else if (x == -1)
425 return (k & 1) ? -1 : 1;
426 else
427 return 0;
428 }
429 return (int64_t)lj_carith_powu64((uint64_t)x, (uint64_t)k);
430}
431
432#endif
433