dasm_arm.h (13423B)
1 /* 2 ** DynASM ARM 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 "arm" 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_IMM12, DASM_IMM16, DASM_IMML8, DASM_IMML12, DASM_IMMV8, 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 int i; 171 for (i = 0; i < 16; i++, n = (n << 2) | (n >> 30)) 172 if (n <= 255) return (int)(n + (i << 8)); 173 return -1; 174 } 175 176 /* Pass 1: Store actions and args, link branches/labels, estimate offsets. */ 177 void dasm_put(Dst_DECL, int start, ...) 178 { 179 va_list ap; 180 dasm_State *D = Dst_REF; 181 dasm_ActList p = D->actionlist + start; 182 dasm_Section *sec = D->section; 183 int pos = sec->pos, ofs = sec->ofs; 184 int *b; 185 186 if (pos >= sec->epos) { 187 DASM_M_GROW(Dst, int, sec->buf, sec->bsize, 188 sec->bsize + 2*DASM_MAXSECPOS*sizeof(int)); 189 sec->rbuf = sec->buf - DASM_POS2BIAS(pos); 190 sec->epos = (int)sec->bsize/sizeof(int) - DASM_MAXSECPOS+DASM_POS2BIAS(pos); 191 } 192 193 b = sec->rbuf; 194 b[pos++] = start; 195 196 va_start(ap, start); 197 while (1) { 198 unsigned int ins = *p++; 199 unsigned int action = (ins >> 16); 200 if (action >= DASM__MAX) { 201 ofs += 4; 202 } else { 203 int *pl, n = action >= DASM_REL_PC ? va_arg(ap, int) : 0; 204 switch (action) { 205 case DASM_STOP: goto stop; 206 case DASM_SECTION: 207 n = (ins & 255); CK(n < D->maxsection, RANGE_SEC); 208 D->section = &D->sections[n]; goto stop; 209 case DASM_ESC: p++; ofs += 4; break; 210 case DASM_REL_EXT: break; 211 case DASM_ALIGN: ofs += (ins & 255); b[pos++] = ofs; break; 212 case DASM_REL_LG: 213 n = (ins & 2047) - 10; pl = D->lglabels + n; 214 /* Bkwd rel or global. */ 215 if (n >= 0) { CK(n>=10||*pl<0, RANGE_LG); CKPL(lg, LG); goto putrel; } 216 pl += 10; n = *pl; 217 if (n < 0) n = 0; /* Start new chain for fwd rel if label exists. */ 218 goto linkrel; 219 case DASM_REL_PC: 220 pl = D->pclabels + n; CKPL(pc, PC); 221 putrel: 222 n = *pl; 223 if (n < 0) { /* Label exists. Get label pos and store it. */ 224 b[pos] = -n; 225 } else { 226 linkrel: 227 b[pos] = n; /* Else link to rel chain, anchored at label. */ 228 *pl = pos; 229 } 230 pos++; 231 break; 232 case DASM_LABEL_LG: 233 pl = D->lglabels + (ins & 2047) - 10; CKPL(lg, LG); goto putlabel; 234 case DASM_LABEL_PC: 235 pl = D->pclabels + n; CKPL(pc, PC); 236 putlabel: 237 n = *pl; /* n > 0: Collapse rel chain and replace with label pos. */ 238 while (n > 0) { int *pb = DASM_POS2PTR(D, n); n = *pb; *pb = pos; 239 } 240 *pl = -pos; /* Label exists now. */ 241 b[pos++] = ofs; /* Store pass1 offset estimate. */ 242 break; 243 case DASM_IMM: 244 case DASM_IMM16: 245 #ifdef DASM_CHECKS 246 CK((n & ((1<<((ins>>10)&31))-1)) == 0, RANGE_I); 247 if ((ins & 0x8000)) 248 CK(((n + (1<<(((ins>>5)&31)-1)))>>((ins>>5)&31)) == 0, RANGE_I); 249 else 250 CK((n>>((ins>>5)&31)) == 0, RANGE_I); 251 #endif 252 b[pos++] = n; 253 break; 254 case DASM_IMMV8: 255 CK((n & 3) == 0, RANGE_I); 256 n >>= 2; 257 case DASM_IMML8: 258 case DASM_IMML12: 259 CK(n >= 0 ? ((n>>((ins>>5)&31)) == 0) : 260 (((-n)>>((ins>>5)&31)) == 0), RANGE_I); 261 b[pos++] = n; 262 break; 263 case DASM_IMM12: 264 CK(dasm_imm12((unsigned int)n) != -1, RANGE_I); 265 b[pos++] = n; 266 break; 267 } 268 } 269 } 270 stop: 271 va_end(ap); 272 sec->pos = pos; 273 sec->ofs = ofs; 274 } 275 #undef CK 276 277 /* Pass 2: Link sections, shrink aligns, fix label offsets. */ 278 int dasm_link(Dst_DECL, size_t *szp) 279 { 280 dasm_State *D = Dst_REF; 281 int secnum; 282 int ofs = 0; 283 284 #ifdef DASM_CHECKS 285 *szp = 0; 286 if (D->status != DASM_S_OK) return D->status; 287 { 288 int pc; 289 for (pc = 0; pc*sizeof(int) < D->pcsize; pc++) 290 if (D->pclabels[pc] > 0) return DASM_S_UNDEF_PC|pc; 291 } 292 #endif 293 294 { /* Handle globals not defined in this translation unit. */ 295 int idx; 296 for (idx = 20; idx*sizeof(int) < D->lgsize; idx++) { 297 int n = D->lglabels[idx]; 298 /* Undefined label: Collapse rel chain and replace with marker (< 0). */ 299 while (n > 0) { int *pb = DASM_POS2PTR(D, n); n = *pb; *pb = -idx; } 300 } 301 } 302 303 /* Combine all code sections. No support for data sections (yet). */ 304 for (secnum = 0; secnum < D->maxsection; secnum++) { 305 dasm_Section *sec = D->sections + secnum; 306 int *b = sec->rbuf; 307 int pos = DASM_SEC2POS(secnum); 308 int lastpos = sec->pos; 309 310 while (pos != lastpos) { 311 dasm_ActList p = D->actionlist + b[pos++]; 312 while (1) { 313 unsigned int ins = *p++; 314 unsigned int action = (ins >> 16); 315 switch (action) { 316 case DASM_STOP: case DASM_SECTION: goto stop; 317 case DASM_ESC: p++; break; 318 case DASM_REL_EXT: break; 319 case DASM_ALIGN: ofs -= (b[pos++] + ofs) & (ins & 255); break; 320 case DASM_REL_LG: case DASM_REL_PC: pos++; break; 321 case DASM_LABEL_LG: case DASM_LABEL_PC: b[pos++] += ofs; break; 322 case DASM_IMM: case DASM_IMM12: case DASM_IMM16: 323 case DASM_IMML8: case DASM_IMML12: case DASM_IMMV8: pos++; break; 324 } 325 } 326 stop: (void)0; 327 } 328 ofs += sec->ofs; /* Next section starts right after current section. */ 329 } 330 331 D->codesize = ofs; /* Total size of all code sections */ 332 *szp = ofs; 333 return DASM_S_OK; 334 } 335 336 #ifdef DASM_CHECKS 337 #define CK(x, st) \ 338 do { if (!(x)) return DASM_S_##st|(p-D->actionlist-1); } while (0) 339 #else 340 #define CK(x, st) ((void)0) 341 #endif 342 343 /* Pass 3: Encode sections. */ 344 int dasm_encode(Dst_DECL, void *buffer) 345 { 346 dasm_State *D = Dst_REF; 347 char *base = (char *)buffer; 348 unsigned int *cp = (unsigned int *)buffer; 349 int secnum; 350 351 /* Encode all code sections. No support for data sections (yet). */ 352 for (secnum = 0; secnum < D->maxsection; secnum++) { 353 dasm_Section *sec = D->sections + secnum; 354 int *b = sec->buf; 355 int *endb = sec->rbuf + sec->pos; 356 357 while (b != endb) { 358 dasm_ActList p = D->actionlist + *b++; 359 while (1) { 360 unsigned int ins = *p++; 361 unsigned int action = (ins >> 16); 362 int n = (action >= DASM_ALIGN && action < DASM__MAX) ? *b++ : 0; 363 switch (action) { 364 case DASM_STOP: case DASM_SECTION: goto stop; 365 case DASM_ESC: *cp++ = *p++; break; 366 case DASM_REL_EXT: 367 n = DASM_EXTERN(Dst, (unsigned char *)cp, (ins&2047), !(ins&2048)); 368 goto patchrel; 369 case DASM_ALIGN: 370 ins &= 255; while ((((char *)cp - base) & ins)) *cp++ = 0xe1a00000; 371 break; 372 case DASM_REL_LG: 373 CK(n >= 0, UNDEF_LG); 374 case DASM_REL_PC: 375 CK(n >= 0, UNDEF_PC); 376 n = *DASM_POS2PTR(D, n) - (int)((char *)cp - base) - 4; 377 patchrel: 378 if ((ins & 0x800) == 0) { 379 CK((n & 3) == 0 && ((n+0x02000000) >> 26) == 0, RANGE_REL); 380 cp[-1] |= ((n >> 2) & 0x00ffffff); 381 } else if ((ins & 0x1000)) { 382 CK((n & 3) == 0 && -256 <= n && n <= 256, RANGE_REL); 383 goto patchimml8; 384 } else if ((ins & 0x2000) == 0) { 385 CK((n & 3) == 0 && -4096 <= n && n <= 4096, RANGE_REL); 386 goto patchimml; 387 } else { 388 CK((n & 3) == 0 && -1020 <= n && n <= 1020, RANGE_REL); 389 n >>= 2; 390 goto patchimml; 391 } 392 break; 393 case DASM_LABEL_LG: 394 ins &= 2047; if (ins >= 20) D->globals[ins-10] = (void *)(base + n); 395 break; 396 case DASM_LABEL_PC: break; 397 case DASM_IMM: 398 cp[-1] |= ((n>>((ins>>10)&31)) & ((1<<((ins>>5)&31))-1)) << (ins&31); 399 break; 400 case DASM_IMM12: 401 cp[-1] |= dasm_imm12((unsigned int)n); 402 break; 403 case DASM_IMM16: 404 cp[-1] |= ((n & 0xf000) << 4) | (n & 0x0fff); 405 break; 406 case DASM_IMML8: patchimml8: 407 cp[-1] |= n >= 0 ? (0x00800000 | (n & 0x0f) | ((n & 0xf0) << 4)) : 408 ((-n & 0x0f) | ((-n & 0xf0) << 4)); 409 break; 410 case DASM_IMML12: case DASM_IMMV8: patchimml: 411 cp[-1] |= n >= 0 ? (0x00800000 | n) : (-n); 412 break; 413 default: *cp++ = ins; break; 414 } 415 } 416 stop: (void)0; 417 } 418 } 419 420 if (base + D->codesize != (char *)cp) /* Check for phase errors. */ 421 return DASM_S_PHASE; 422 return DASM_S_OK; 423 } 424 #undef CK 425 426 /* Get PC label offset. */ 427 int dasm_getpclabel(Dst_DECL, unsigned int pc) 428 { 429 dasm_State *D = Dst_REF; 430 if (pc*sizeof(int) < D->pcsize) { 431 int pos = D->pclabels[pc]; 432 if (pos < 0) return *DASM_POS2PTR(D, -pos); 433 if (pos > 0) return -1; /* Undefined. */ 434 } 435 return -2; /* Unused or out of range. */ 436 } 437 438 #ifdef DASM_CHECKS 439 /* Optional sanity checker to call between isolated encoding steps. */ 440 int dasm_checkstep(Dst_DECL, int secmatch) 441 { 442 dasm_State *D = Dst_REF; 443 if (D->status == DASM_S_OK) { 444 int i; 445 for (i = 1; i <= 9; i++) { 446 if (D->lglabels[i] > 0) { D->status = DASM_S_UNDEF_LG|i; break; } 447 D->lglabels[i] = 0; 448 } 449 } 450 if (D->status == DASM_S_OK && secmatch >= 0 && 451 D->section != &D->sections[secmatch]) 452 D->status = DASM_S_MATCH_SEC|(D->section-D->sections); 453 return D->status; 454 } 455 #endif 456