root/dasm_arm64.h

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DEFINITIONS

This source file includes following definitions.
  1. dasm_init
  2. dasm_free
  3. dasm_setupglobal
  4. dasm_growpc
  5. dasm_setup
  6. dasm_imm12
  7. dasm_ffs
  8. dasm_imm13
  9. dasm_put
  10. dasm_link
  11. dasm_encode
  12. dasm_getpclabel
  13. dasm_checkstep

   1 /*
   2 ** DynASM ARM64 encoding engine.
   3 ** Copyright (C) 2005-2017 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 

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