dasm_arm64.h (15053B)
1 /* 2 ** DynASM ARM64 encoding engine. 3 ** Copyright (C) 2005-2016 Mike Pall. All rights reserved. 4 ** Released under the MIT license. See dynasm.lua for full copyright notice. 5 */ 6 7 #include <stddef.h> 8 #include <stdarg.h> 9 #include <string.h> 10 #include <stdlib.h> 11 12 #define DASM_ARCH "arm64" 13 14 #ifndef DASM_EXTERN 15 #define DASM_EXTERN(a,b,c,d) 0 16 #endif 17 18 /* Action definitions. */ 19 enum { 20 DASM_STOP, DASM_SECTION, DASM_ESC, DASM_REL_EXT, 21 /* The following actions need a buffer position. */ 22 DASM_ALIGN, DASM_REL_LG, DASM_LABEL_LG, 23 /* The following actions also have an argument. */ 24 DASM_REL_PC, DASM_LABEL_PC, 25 DASM_IMM, DASM_IMM6, DASM_IMM12, DASM_IMM13W, DASM_IMM13X, DASM_IMML, 26 DASM__MAX 27 }; 28 29 /* Maximum number of section buffer positions for a single dasm_put() call. */ 30 #define DASM_MAXSECPOS 25 31 32 /* DynASM encoder status codes. Action list offset or number are or'ed in. */ 33 #define DASM_S_OK 0x00000000 34 #define DASM_S_NOMEM 0x01000000 35 #define DASM_S_PHASE 0x02000000 36 #define DASM_S_MATCH_SEC 0x03000000 37 #define DASM_S_RANGE_I 0x11000000 38 #define DASM_S_RANGE_SEC 0x12000000 39 #define DASM_S_RANGE_LG 0x13000000 40 #define DASM_S_RANGE_PC 0x14000000 41 #define DASM_S_RANGE_REL 0x15000000 42 #define DASM_S_UNDEF_LG 0x21000000 43 #define DASM_S_UNDEF_PC 0x22000000 44 45 /* Macros to convert positions (8 bit section + 24 bit index). */ 46 #define DASM_POS2IDX(pos) ((pos)&0x00ffffff) 47 #define DASM_POS2BIAS(pos) ((pos)&0xff000000) 48 #define DASM_SEC2POS(sec) ((sec)<<24) 49 #define DASM_POS2SEC(pos) ((pos)>>24) 50 #define DASM_POS2PTR(D, pos) (D->sections[DASM_POS2SEC(pos)].rbuf + (pos)) 51 52 /* Action list type. */ 53 typedef const unsigned int *dasm_ActList; 54 55 /* Per-section structure. */ 56 typedef struct dasm_Section { 57 int *rbuf; /* Biased buffer pointer (negative section bias). */ 58 int *buf; /* True buffer pointer. */ 59 size_t bsize; /* Buffer size in bytes. */ 60 int pos; /* Biased buffer position. */ 61 int epos; /* End of biased buffer position - max single put. */ 62 int ofs; /* Byte offset into section. */ 63 } dasm_Section; 64 65 /* Core structure holding the DynASM encoding state. */ 66 struct dasm_State { 67 size_t psize; /* Allocated size of this structure. */ 68 dasm_ActList actionlist; /* Current actionlist pointer. */ 69 int *lglabels; /* Local/global chain/pos ptrs. */ 70 size_t lgsize; 71 int *pclabels; /* PC label chains/pos ptrs. */ 72 size_t pcsize; 73 void **globals; /* Array of globals (bias -10). */ 74 dasm_Section *section; /* Pointer to active section. */ 75 size_t codesize; /* Total size of all code sections. */ 76 int maxsection; /* 0 <= sectionidx < maxsection. */ 77 int status; /* Status code. */ 78 dasm_Section sections[1]; /* All sections. Alloc-extended. */ 79 }; 80 81 /* The size of the core structure depends on the max. number of sections. */ 82 #define DASM_PSZ(ms) (sizeof(dasm_State)+(ms-1)*sizeof(dasm_Section)) 83 84 85 /* Initialize DynASM state. */ 86 void dasm_init(Dst_DECL, int maxsection) 87 { 88 dasm_State *D; 89 size_t psz = 0; 90 int i; 91 Dst_REF = NULL; 92 DASM_M_GROW(Dst, struct dasm_State, Dst_REF, psz, DASM_PSZ(maxsection)); 93 D = Dst_REF; 94 D->psize = psz; 95 D->lglabels = NULL; 96 D->lgsize = 0; 97 D->pclabels = NULL; 98 D->pcsize = 0; 99 D->globals = NULL; 100 D->maxsection = maxsection; 101 for (i = 0; i < maxsection; i++) { 102 D->sections[i].buf = NULL; /* Need this for pass3. */ 103 D->sections[i].rbuf = D->sections[i].buf - DASM_SEC2POS(i); 104 D->sections[i].bsize = 0; 105 D->sections[i].epos = 0; /* Wrong, but is recalculated after resize. */ 106 } 107 } 108 109 /* Free DynASM state. */ 110 void dasm_free(Dst_DECL) 111 { 112 dasm_State *D = Dst_REF; 113 int i; 114 for (i = 0; i < D->maxsection; i++) 115 if (D->sections[i].buf) 116 DASM_M_FREE(Dst, D->sections[i].buf, D->sections[i].bsize); 117 if (D->pclabels) DASM_M_FREE(Dst, D->pclabels, D->pcsize); 118 if (D->lglabels) DASM_M_FREE(Dst, D->lglabels, D->lgsize); 119 DASM_M_FREE(Dst, D, D->psize); 120 } 121 122 /* Setup global label array. Must be called before dasm_setup(). */ 123 void dasm_setupglobal(Dst_DECL, void **gl, unsigned int maxgl) 124 { 125 dasm_State *D = Dst_REF; 126 D->globals = gl - 10; /* Negative bias to compensate for locals. */ 127 DASM_M_GROW(Dst, int, D->lglabels, D->lgsize, (10+maxgl)*sizeof(int)); 128 } 129 130 /* Grow PC label array. Can be called after dasm_setup(), too. */ 131 void dasm_growpc(Dst_DECL, unsigned int maxpc) 132 { 133 dasm_State *D = Dst_REF; 134 size_t osz = D->pcsize; 135 DASM_M_GROW(Dst, int, D->pclabels, D->pcsize, maxpc*sizeof(int)); 136 memset((void *)(((unsigned char *)D->pclabels)+osz), 0, D->pcsize-osz); 137 } 138 139 /* Setup encoder. */ 140 void dasm_setup(Dst_DECL, const void *actionlist) 141 { 142 dasm_State *D = Dst_REF; 143 int i; 144 D->actionlist = (dasm_ActList)actionlist; 145 D->status = DASM_S_OK; 146 D->section = &D->sections[0]; 147 memset((void *)D->lglabels, 0, D->lgsize); 148 if (D->pclabels) memset((void *)D->pclabels, 0, D->pcsize); 149 for (i = 0; i < D->maxsection; i++) { 150 D->sections[i].pos = DASM_SEC2POS(i); 151 D->sections[i].ofs = 0; 152 } 153 } 154 155 156 #ifdef DASM_CHECKS 157 #define CK(x, st) \ 158 do { if (!(x)) { \ 159 D->status = DASM_S_##st|(p-D->actionlist-1); return; } } while (0) 160 #define CKPL(kind, st) \ 161 do { if ((size_t)((char *)pl-(char *)D->kind##labels) >= D->kind##size) { \ 162 D->status = DASM_S_RANGE_##st|(p-D->actionlist-1); return; } } while (0) 163 #else 164 #define CK(x, st) ((void)0) 165 #define CKPL(kind, st) ((void)0) 166 #endif 167 168 static int dasm_imm12(unsigned int n) 169 { 170 if ((n >> 12) == 0) 171 return n; 172 else if ((n & 0xff000fff) == 0) 173 return (n >> 12) | 0x1000; 174 else 175 return -1; 176 } 177 178 static int dasm_ffs(unsigned long long x) 179 { 180 int n = -1; 181 while (x) { x >>= 1; n++; } 182 return n; 183 } 184 185 static int dasm_imm13(int lo, int hi) 186 { 187 int inv = 0, w = 64, s = 0xfff, xa, xb; 188 unsigned long long n = (((unsigned long long)hi) << 32) | (unsigned int)lo; 189 unsigned long long m = 1ULL, a, b, c; 190 if (n & 1) { n = ~n; inv = 1; } 191 a = n & -n; b = (n+a)&-(n+a); c = (n+a-b)&-(n+a-b); 192 xa = dasm_ffs(a); xb = dasm_ffs(b); 193 if (c) { 194 w = dasm_ffs(c) - xa; 195 if (w == 32) m = 0x0000000100000001UL; 196 else if (w == 16) m = 0x0001000100010001UL; 197 else if (w == 8) m = 0x0101010101010101UL; 198 else if (w == 4) m = 0x1111111111111111UL; 199 else if (w == 2) m = 0x5555555555555555UL; 200 else return -1; 201 s = (-2*w & 0x3f) - 1; 202 } else if (!a) { 203 return -1; 204 } else if (xb == -1) { 205 xb = 64; 206 } 207 if ((b-a) * m != n) return -1; 208 if (inv) { 209 return ((w - xb) << 6) | (s+w+xa-xb); 210 } else { 211 return ((w - xa) << 6) | (s+xb-xa); 212 } 213 return -1; 214 } 215 216 /* Pass 1: Store actions and args, link branches/labels, estimate offsets. */ 217 void dasm_put(Dst_DECL, int start, ...) 218 { 219 va_list ap; 220 dasm_State *D = Dst_REF; 221 dasm_ActList p = D->actionlist + start; 222 dasm_Section *sec = D->section; 223 int pos = sec->pos, ofs = sec->ofs; 224 int *b; 225 226 if (pos >= sec->epos) { 227 DASM_M_GROW(Dst, int, sec->buf, sec->bsize, 228 sec->bsize + 2*DASM_MAXSECPOS*sizeof(int)); 229 sec->rbuf = sec->buf - DASM_POS2BIAS(pos); 230 sec->epos = (int)sec->bsize/sizeof(int) - DASM_MAXSECPOS+DASM_POS2BIAS(pos); 231 } 232 233 b = sec->rbuf; 234 b[pos++] = start; 235 236 va_start(ap, start); 237 while (1) { 238 unsigned int ins = *p++; 239 unsigned int action = (ins >> 16); 240 if (action >= DASM__MAX) { 241 ofs += 4; 242 } else { 243 int *pl, n = action >= DASM_REL_PC ? va_arg(ap, int) : 0; 244 switch (action) { 245 case DASM_STOP: goto stop; 246 case DASM_SECTION: 247 n = (ins & 255); CK(n < D->maxsection, RANGE_SEC); 248 D->section = &D->sections[n]; goto stop; 249 case DASM_ESC: p++; ofs += 4; break; 250 case DASM_REL_EXT: break; 251 case DASM_ALIGN: ofs += (ins & 255); b[pos++] = ofs; break; 252 case DASM_REL_LG: 253 n = (ins & 2047) - 10; pl = D->lglabels + n; 254 /* Bkwd rel or global. */ 255 if (n >= 0) { CK(n>=10||*pl<0, RANGE_LG); CKPL(lg, LG); goto putrel; } 256 pl += 10; n = *pl; 257 if (n < 0) n = 0; /* Start new chain for fwd rel if label exists. */ 258 goto linkrel; 259 case DASM_REL_PC: 260 pl = D->pclabels + n; CKPL(pc, PC); 261 putrel: 262 n = *pl; 263 if (n < 0) { /* Label exists. Get label pos and store it. */ 264 b[pos] = -n; 265 } else { 266 linkrel: 267 b[pos] = n; /* Else link to rel chain, anchored at label. */ 268 *pl = pos; 269 } 270 pos++; 271 break; 272 case DASM_LABEL_LG: 273 pl = D->lglabels + (ins & 2047) - 10; CKPL(lg, LG); goto putlabel; 274 case DASM_LABEL_PC: 275 pl = D->pclabels + n; CKPL(pc, PC); 276 putlabel: 277 n = *pl; /* n > 0: Collapse rel chain and replace with label pos. */ 278 while (n > 0) { int *pb = DASM_POS2PTR(D, n); n = *pb; *pb = pos; 279 } 280 *pl = -pos; /* Label exists now. */ 281 b[pos++] = ofs; /* Store pass1 offset estimate. */ 282 break; 283 case DASM_IMM: 284 CK((n & ((1<<((ins>>10)&31))-1)) == 0, RANGE_I); 285 n >>= ((ins>>10)&31); 286 #ifdef DASM_CHECKS 287 if ((ins & 0x8000)) 288 CK(((n + (1<<(((ins>>5)&31)-1)))>>((ins>>5)&31)) == 0, RANGE_I); 289 else 290 CK((n>>((ins>>5)&31)) == 0, RANGE_I); 291 #endif 292 b[pos++] = n; 293 break; 294 case DASM_IMM6: 295 CK((n >> 6) == 0, RANGE_I); 296 b[pos++] = n; 297 break; 298 case DASM_IMM12: 299 CK(dasm_imm12((unsigned int)n) != -1, RANGE_I); 300 b[pos++] = n; 301 break; 302 case DASM_IMM13W: 303 CK(dasm_imm13(n, n) != -1, RANGE_I); 304 b[pos++] = n; 305 break; 306 case DASM_IMM13X: { 307 int m = va_arg(ap, int); 308 CK(dasm_imm13(n, m) != -1, RANGE_I); 309 b[pos++] = n; 310 b[pos++] = m; 311 break; 312 } 313 case DASM_IMML: { 314 #ifdef DASM_CHECKS 315 int scale = (p[-2] >> 30); 316 CK((!(n & ((1<<scale)-1)) && (unsigned int)(n>>scale) < 4096) || 317 (unsigned int)(n+256) < 512, RANGE_I); 318 #endif 319 b[pos++] = n; 320 break; 321 } 322 } 323 } 324 } 325 stop: 326 va_end(ap); 327 sec->pos = pos; 328 sec->ofs = ofs; 329 } 330 #undef CK 331 332 /* Pass 2: Link sections, shrink aligns, fix label offsets. */ 333 int dasm_link(Dst_DECL, size_t *szp) 334 { 335 dasm_State *D = Dst_REF; 336 int secnum; 337 int ofs = 0; 338 339 #ifdef DASM_CHECKS 340 *szp = 0; 341 if (D->status != DASM_S_OK) return D->status; 342 { 343 int pc; 344 for (pc = 0; pc*sizeof(int) < D->pcsize; pc++) 345 if (D->pclabels[pc] > 0) return DASM_S_UNDEF_PC|pc; 346 } 347 #endif 348 349 { /* Handle globals not defined in this translation unit. */ 350 int idx; 351 for (idx = 20; idx*sizeof(int) < D->lgsize; idx++) { 352 int n = D->lglabels[idx]; 353 /* Undefined label: Collapse rel chain and replace with marker (< 0). */ 354 while (n > 0) { int *pb = DASM_POS2PTR(D, n); n = *pb; *pb = -idx; } 355 } 356 } 357 358 /* Combine all code sections. No support for data sections (yet). */ 359 for (secnum = 0; secnum < D->maxsection; secnum++) { 360 dasm_Section *sec = D->sections + secnum; 361 int *b = sec->rbuf; 362 int pos = DASM_SEC2POS(secnum); 363 int lastpos = sec->pos; 364 365 while (pos != lastpos) { 366 dasm_ActList p = D->actionlist + b[pos++]; 367 while (1) { 368 unsigned int ins = *p++; 369 unsigned int action = (ins >> 16); 370 switch (action) { 371 case DASM_STOP: case DASM_SECTION: goto stop; 372 case DASM_ESC: p++; break; 373 case DASM_REL_EXT: break; 374 case DASM_ALIGN: ofs -= (b[pos++] + ofs) & (ins & 255); break; 375 case DASM_REL_LG: case DASM_REL_PC: pos++; break; 376 case DASM_LABEL_LG: case DASM_LABEL_PC: b[pos++] += ofs; break; 377 case DASM_IMM: case DASM_IMM6: case DASM_IMM12: case DASM_IMM13W: 378 case DASM_IMML: pos++; break; 379 case DASM_IMM13X: pos += 2; break; 380 } 381 } 382 stop: (void)0; 383 } 384 ofs += sec->ofs; /* Next section starts right after current section. */ 385 } 386 387 D->codesize = ofs; /* Total size of all code sections */ 388 *szp = ofs; 389 return DASM_S_OK; 390 } 391 392 #ifdef DASM_CHECKS 393 #define CK(x, st) \ 394 do { if (!(x)) return DASM_S_##st|(p-D->actionlist-1); } while (0) 395 #else 396 #define CK(x, st) ((void)0) 397 #endif 398 399 /* Pass 3: Encode sections. */ 400 int dasm_encode(Dst_DECL, void *buffer) 401 { 402 dasm_State *D = Dst_REF; 403 char *base = (char *)buffer; 404 unsigned int *cp = (unsigned int *)buffer; 405 int secnum; 406 407 /* Encode all code sections. No support for data sections (yet). */ 408 for (secnum = 0; secnum < D->maxsection; secnum++) { 409 dasm_Section *sec = D->sections + secnum; 410 int *b = sec->buf; 411 int *endb = sec->rbuf + sec->pos; 412 413 while (b != endb) { 414 dasm_ActList p = D->actionlist + *b++; 415 while (1) { 416 unsigned int ins = *p++; 417 unsigned int action = (ins >> 16); 418 int n = (action >= DASM_ALIGN && action < DASM__MAX) ? *b++ : 0; 419 switch (action) { 420 case DASM_STOP: case DASM_SECTION: goto stop; 421 case DASM_ESC: *cp++ = *p++; break; 422 case DASM_REL_EXT: 423 n = DASM_EXTERN(Dst, (unsigned char *)cp, (ins&2047), !(ins&2048)); 424 goto patchrel; 425 case DASM_ALIGN: 426 ins &= 255; while ((((char *)cp - base) & ins)) *cp++ = 0xe1a00000; 427 break; 428 case DASM_REL_LG: 429 CK(n >= 0, UNDEF_LG); 430 case DASM_REL_PC: 431 CK(n >= 0, UNDEF_PC); 432 n = *DASM_POS2PTR(D, n) - (int)((char *)cp - base) + 4; 433 patchrel: 434 if (!(ins & 0xf800)) { /* B, BL */ 435 CK((n & 3) == 0 && ((n+0x08000000) >> 28) == 0, RANGE_REL); 436 cp[-1] |= ((n >> 2) & 0x03ffffff); 437 } else if ((ins & 0x800)) { /* B.cond, CBZ, CBNZ, LDR* literal */ 438 CK((n & 3) == 0 && ((n+0x00100000) >> 21) == 0, RANGE_REL); 439 cp[-1] |= ((n << 3) & 0x00ffffe0); 440 } else if ((ins & 0x3000) == 0x2000) { /* ADR */ 441 CK(((n+0x00100000) >> 21) == 0, RANGE_REL); 442 cp[-1] |= ((n << 3) & 0x00ffffe0) | ((n & 3) << 29); 443 } else if ((ins & 0x3000) == 0x3000) { /* ADRP */ 444 cp[-1] |= ((n >> 9) & 0x00ffffe0) | (((n >> 12) & 3) << 29); 445 } else if ((ins & 0x1000)) { /* TBZ, TBNZ */ 446 CK((n & 3) == 0 && ((n+0x00008000) >> 16) == 0, RANGE_REL); 447 cp[-1] |= ((n << 3) & 0x0007ffe0); 448 } 449 break; 450 case DASM_LABEL_LG: 451 ins &= 2047; if (ins >= 20) D->globals[ins-10] = (void *)(base + n); 452 break; 453 case DASM_LABEL_PC: break; 454 case DASM_IMM: 455 cp[-1] |= (n & ((1<<((ins>>5)&31))-1)) << (ins&31); 456 break; 457 case DASM_IMM6: 458 cp[-1] |= ((n&31) << 19) | ((n&32) << 26); 459 break; 460 case DASM_IMM12: 461 cp[-1] |= (dasm_imm12((unsigned int)n) << 10); 462 break; 463 case DASM_IMM13W: 464 cp[-1] |= (dasm_imm13(n, n) << 10); 465 break; 466 case DASM_IMM13X: 467 cp[-1] |= (dasm_imm13(n, *b++) << 10); 468 break; 469 case DASM_IMML: { 470 int scale = (p[-2] >> 30); 471 cp[-1] |= (!(n & ((1<<scale)-1)) && (unsigned int)(n>>scale) < 4096) ? 472 ((n << (10-scale)) | 0x01000000) : ((n & 511) << 12); 473 break; 474 } 475 default: *cp++ = ins; break; 476 } 477 } 478 stop: (void)0; 479 } 480 } 481 482 if (base + D->codesize != (char *)cp) /* Check for phase errors. */ 483 return DASM_S_PHASE; 484 return DASM_S_OK; 485 } 486 #undef CK 487 488 /* Get PC label offset. */ 489 int dasm_getpclabel(Dst_DECL, unsigned int pc) 490 { 491 dasm_State *D = Dst_REF; 492 if (pc*sizeof(int) < D->pcsize) { 493 int pos = D->pclabels[pc]; 494 if (pos < 0) return *DASM_POS2PTR(D, -pos); 495 if (pos > 0) return -1; /* Undefined. */ 496 } 497 return -2; /* Unused or out of range. */ 498 } 499 500 #ifdef DASM_CHECKS 501 /* Optional sanity checker to call between isolated encoding steps. */ 502 int dasm_checkstep(Dst_DECL, int secmatch) 503 { 504 dasm_State *D = Dst_REF; 505 if (D->status == DASM_S_OK) { 506 int i; 507 for (i = 1; i <= 9; i++) { 508 if (D->lglabels[i] > 0) { D->status = DASM_S_UNDEF_LG|i; break; } 509 D->lglabels[i] = 0; 510 } 511 } 512 if (D->status == DASM_S_OK && secmatch >= 0 && 513 D->section != &D->sections[secmatch]) 514 D->status = DASM_S_MATCH_SEC|(D->section-D->sections); 515 return D->status; 516 } 517 #endif 518