tccasm.c

   1 /*
   2  *  GAS like assembler for TCC
   3  *
   4  *  Copyright (c) 2001-2004 Fabrice Bellard
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  */
  20
  21 #include "tcc.h"
  22 #ifdef CONFIG_TCC_ASM
  23
  24 ST_FUNC int asm_get_local_label_name(TCCState *s1, unsigned int n)
  25 {
  26     char buf[64];
  27     TokenSym *ts;
  28
  29     snprintf(buf, sizeof(buf), "L..%u", n);
  30     ts = tok_alloc(buf, strlen(buf));
  31     return ts->tok;
  32 }
  33
  34 ST_FUNC void asm_expr(TCCState *s1, ExprValue *pe);
  35
  36 /* We do not use the C expression parser to handle symbols. Maybe the
  37    C expression parser could be tweaked to do so. */
  38
  39 static void asm_expr_unary(TCCState *s1, ExprValue *pe)
  40 {
  41     Sym *sym;
  42     int op, n, label;
  43     const char *p;
  44
  45     switch(tok) {
  46     case TOK_PPNUM:
  47         p = tokc.cstr->data;
  48         n = strtoul(p, (char **)&p, 0);
  49         if (*p == 'b' || *p == 'f') {
  50             /* backward or forward label */
  51             label = asm_get_local_label_name(s1, n);
  52             sym = label_find(label);
  53             if (*p == 'b') {
  54                 /* backward : find the last corresponding defined label */
  55                 if (sym && sym->r == 0)
  56                     sym = sym->prev_tok;
  57                 if (!sym)
  58                     tcc_error("local label '%d' not found backward", n);
  59             } else {
  60                 /* forward */
  61                 if (!sym || sym->r) {
  62                     /* if the last label is defined, then define a new one */
  63                     sym = label_push(&s1->asm_labels, label, 0);
  64                     sym->type.t = VT_STATIC | VT_VOID;
  65                 }
  66             }
  67             pe->v = 0;
  68             pe->sym = sym;
  69         } else if (*p == '\0') {
  70             pe->v = n;
  71             pe->sym = NULL;
  72         } else {
  73             tcc_error("invalid number syntax");
  74         }
  75         next();
  76         break;
  77     case '+':
  78         next();
  79         asm_expr_unary(s1, pe);
  80         break;
  81     case '-':
  82     case '~':
  83         op = tok;
  84         next();
  85         asm_expr_unary(s1, pe);
  86         if (pe->sym)
  87             tcc_error("invalid operation with label");
  88         if (op == '-')
  89             pe->v = -pe->v;
  90         else
  91             pe->v = ~pe->v;
  92         break;
  93     case TOK_CCHAR:
  94     case TOK_LCHAR:
  95         pe->v = tokc.i;
  96         pe->sym = NULL;
  97         next();
  98         break;
  99     case '(':
 100         next();
 101         asm_expr(s1, pe);
 102         skip(')');
 103         break;
 104     default:
 105         if (tok >= TOK_IDENT) {
 106             /* label case : if the label was not found, add one */
 107             sym = label_find(tok);
 108             if (!sym) {
 109                 sym = label_push(&s1->asm_labels, tok, 0);
 110                 /* NOTE: by default, the symbol is global */
 111                 sym->type.t = VT_VOID;
 112             }
 113             if (sym->r == SHN_ABS) {
 114                 /* if absolute symbol, no need to put a symbol value */
 115                 pe->v = sym->jnext;
 116                 pe->sym = NULL;
 117             } else {
 118                 pe->v = 0;
 119                 pe->sym = sym;
 120             }
 121             next();
 122         } else {
 123             tcc_error("bad expression syntax [%s]", get_tok_str(tok, &tokc));
 124         }
 125         break;
 126     }
 127 }
 128
 129 static void asm_expr_prod(TCCState *s1, ExprValue *pe)
 130 {
 131     int op;
 132     ExprValue e2;
 133
 134     asm_expr_unary(s1, pe);
 135     for(;;) {
 136         op = tok;
 137         if (op != '*' && op != '/' && op != '%' &&
 138             op != TOK_SHL && op != TOK_SAR)
 139             break;
 140         next();
 141         asm_expr_unary(s1, &e2);
 142         if (pe->sym || e2.sym)
 143             tcc_error("invalid operation with label");
 144         switch(op) {
 145         case '*':
 146             pe->v *= e2.v;
 147             break;
 148         case '/':
 149             if (e2.v == 0) {
 150             div_error:
 151                 tcc_error("division by zero");
 152             }
 153             pe->v /= e2.v;
 154             break;
 155         case '%':
 156             if (e2.v == 0)
 157                 goto div_error;
 158             pe->v %= e2.v;
 159             break;
 160         case TOK_SHL:
 161             pe->v <<= e2.v;
 162             break;
 163         default:
 164         case TOK_SAR:
 165             pe->v >>= e2.v;
 166             break;
 167         }
 168     }
 169 }
 170
 171 static void asm_expr_logic(TCCState *s1, ExprValue *pe)
 172 {
 173     int op;
 174     ExprValue e2;
 175
 176     asm_expr_prod(s1, pe);
 177     for(;;) {
 178         op = tok;
 179         if (op != '&' && op != '|' && op != '^')
 180             break;
 181         next();
 182         asm_expr_prod(s1, &e2);
 183         if (pe->sym || e2.sym)
 184             tcc_error("invalid operation with label");
 185         switch(op) {
 186         case '&':
 187             pe->v &= e2.v;
 188             break;
 189         case '|':
 190             pe->v |= e2.v;
 191             break;
 192         default:
 193         case '^':
 194             pe->v ^= e2.v;
 195             break;
 196         }
 197     }
 198 }
 199
 200 static inline void asm_expr_sum(TCCState *s1, ExprValue *pe)
 201 {
 202     int op;
 203     ExprValue e2;
 204
 205     asm_expr_logic(s1, pe);
 206     for(;;) {
 207         op = tok;
 208         if (op != '+' && op != '-')
 209             break;
 210         next();
 211         asm_expr_logic(s1, &e2);
 212         if (op == '+') {
 213             if (pe->sym != NULL && e2.sym != NULL)
 214                 goto cannot_relocate;
 215             pe->v += e2.v;
 216             if (pe->sym == NULL && e2.sym != NULL)
 217                 pe->sym = e2.sym;
 218         } else {
 219             pe->v -= e2.v;
 220             /* NOTE: we are less powerful than gas in that case
 221                because we store only one symbol in the expression */
 222             if (!pe->sym && !e2.sym) {
 223                 /* OK */
 224             } else if (pe->sym && !e2.sym) {
 225                 /* OK */
 226             } else if (pe->sym && e2.sym) {
 227                 if (pe->sym == e2.sym) {
 228                     /* OK */
 229                 } else if (pe->sym->r == e2.sym->r && pe->sym->r != 0) {
 230                     /* we also accept defined symbols in the same section */
 231                     pe->v += pe->sym->jnext - e2.sym->jnext;
 232                 } else {
 233                     goto cannot_relocate;
 234                 }
 235                 pe->sym = NULL; /* same symbols can be substracted to NULL */
 236             } else {
 237             cannot_relocate:
 238                 tcc_error("invalid operation with label");
 239             }
 240         }
 241     }
 242 }
 243
 244 ST_FUNC void asm_expr(TCCState *s1, ExprValue *pe)
 245 {
 246     asm_expr_sum(s1, pe);
 247 }
 248
 249 ST_FUNC int asm_int_expr(TCCState *s1)
 250 {
 251     ExprValue e;
 252     asm_expr(s1, &e);
 253     if (e.sym)
 254         expect("constant");
 255     return e.v;
 256 }
 257
 258 /* NOTE: the same name space as C labels is used to avoid using too
 259    much memory when storing labels in TokenStrings */
 260 static void asm_new_label1(TCCState *s1, int label, int is_local,
 261                            int sh_num, int value)
 262 {
 263     Sym *sym;
 264
 265     sym = label_find(label);
 266     if (sym) {
 267         if (sym->r) {
 268             /* the label is already defined */
 269             if (!is_local) {
 270                 tcc_error("assembler label '%s' already defined",
 271                       get_tok_str(label, NULL));
 272             } else {
 273                 /* redefinition of local labels is possible */
 274                 goto new_label;
 275             }
 276         }
 277     } else {
 278     new_label:
 279         sym = label_push(&s1->asm_labels, label, 0);
 280         sym->type.t = VT_STATIC | VT_VOID;
 281     }
 282     sym->r = sh_num;
 283     sym->jnext = value;
 284 }
 285
 286 static void asm_new_label(TCCState *s1, int label, int is_local)
 287 {
 288     asm_new_label1(s1, label, is_local, cur_text_section->sh_num, ind);
 289 }
 290
 291 static void asm_free_labels(TCCState *st)
 292 {
 293     Sym *s, *s1;
 294     Section *sec;
 295
 296     for(s = st->asm_labels; s != NULL; s = s1) {
 297         s1 = s->prev;
 298         /* define symbol value in object file */
 299         if (s->r) {
 300             if (s->r == SHN_ABS)
 301                 sec = SECTION_ABS;
 302             else
 303                 sec = st->sections[s->r];
 304             put_extern_sym2(s, sec, s->jnext, 0, 0);
 305         }
 306         /* remove label */
 307         table_ident[s->v - TOK_IDENT]->sym_label = NULL;
 308         sym_free(s);
 309     }
 310     st->asm_labels = NULL;
 311 }
 312
 313 static void use_section1(TCCState *s1, Section *sec)
 314 {
 315     cur_text_section->data_offset = ind;
 316     cur_text_section = sec;
 317     ind = cur_text_section->data_offset;
 318 }
 319
 320 static void use_section(TCCState *s1, const char *name)
 321 {
 322     Section *sec;
 323     sec = find_section(s1, name);
 324     use_section1(s1, sec);
 325 }
 326
 327 static void asm_parse_directive(TCCState *s1)
 328 {
 329     int n, offset, v, size, tok1;
 330     Section *sec;
 331     uint8_t *ptr;
 332
 333     /* assembler directive */
 334     next();
 335     sec = cur_text_section;
 336     switch(tok) {
 337     case TOK_ASM_align:
 338     case TOK_ASM_skip:
 339     case TOK_ASM_space:
 340         tok1 = tok;
 341         next();
 342         n = asm_int_expr(s1);
 343         if (tok1 == TOK_ASM_align) {
 344             if (n < 0 || (n & (n-1)) != 0)
 345                 tcc_error("alignment must be a positive power of two");
 346             offset = (ind + n - 1) & -n;
 347             size = offset - ind;
 348             /* the section must have a compatible alignment */
 349             if (sec->sh_addralign < n)
 350                 sec->sh_addralign = n;
 351         } else {
 352             size = n;
 353         }
 354         v = 0;
 355         if (tok == ',') {
 356             next();
 357             v = asm_int_expr(s1);
 358         }
 359     zero_pad:
 360         if (sec->sh_type != SHT_NOBITS) {
 361             sec->data_offset = ind;
 362             ptr = section_ptr_add(sec, size);
 363             memset(ptr, v, size);
 364         }
 365         ind += size;
 366         break;
 367     case TOK_ASM_quad:
 368         next();
 369         for(;;) {
 370             uint64_t vl;
 371             const char *p;
 372
 373             p = tokc.cstr->data;
 374             if (tok != TOK_PPNUM) {
 375             error_constant:
 376                 tcc_error("64 bit constant");
 377             }
 378             vl = strtoll(p, (char **)&p, 0);
 379             if (*p != '\0')
 380                 goto error_constant;
 381             next();
 382             if (sec->sh_type != SHT_NOBITS) {
 383                 /* XXX: endianness */
 384                 gen_le32(vl);
 385                 gen_le32(vl >> 32);
 386             } else {
 387                 ind += 8;
 388             }
 389             if (tok != ',')
 390                 break;
 391             next();
 392         }
 393         break;
 394     case TOK_ASM_byte:
 395         size = 1;
 396         goto asm_data;
 397     case TOK_ASM_word:
 398     case TOK_SHORT:
 399         size = 2;
 400         goto asm_data;
 401     case TOK_LONG:
 402     case TOK_INT:
 403         size = 4;
 404     asm_data:
 405         next();
 406         for(;;) {
 407             ExprValue e;
 408             asm_expr(s1, &e);
 409             if (sec->sh_type != SHT_NOBITS) {
 410                 if (size == 4) {
 411                     gen_expr32(&e);
 412                 } else {
 413                     if (e.sym)
 414                         expect("constant");
 415                     if (size == 1)
 416                         g(e.v);
 417                     else
 418                         gen_le16(e.v);
 419                 }
 420             } else {
 421                 ind += size;
 422             }
 423             if (tok != ',')
 424                 break;
 425             next();
 426         }
 427         break;
 428     case TOK_ASM_fill:
 429         {
 430             int repeat, size, val, i, j;
 431             uint8_t repeat_buf[8];
 432             next();
 433             repeat = asm_int_expr(s1);
 434             if (repeat < 0) {
 435                 tcc_error("repeat < 0; .fill ignored");
 436                 break;
 437             }
 438             size = 1;
 439             val = 0;
 440             if (tok == ',') {
 441                 next();
 442                 size = asm_int_expr(s1);
 443                 if (size < 0) {
 444                     tcc_error("size < 0; .fill ignored");
 445                     break;
 446                 }
 447                 if (size > 8)
 448                     size = 8;
 449                 if (tok == ',') {
 450                     next();
 451                     val = asm_int_expr(s1);
 452                 }
 453             }
 454             /* XXX: endianness */
 455             repeat_buf[0] = val;
 456             repeat_buf[1] = val >> 8;
 457             repeat_buf[2] = val >> 16;
 458             repeat_buf[3] = val >> 24;
 459             repeat_buf[4] = 0;
 460             repeat_buf[5] = 0;
 461             repeat_buf[6] = 0;
 462             repeat_buf[7] = 0;
 463             for(i = 0; i < repeat; i++) {
 464                 for(j = 0; j < size; j++) {
 465                     g(repeat_buf[j]);
 466                 }
 467             }
 468         }
 469         break;
 470     case TOK_ASM_org:
 471         {
 472             unsigned long n;
 473             next();
 474             /* XXX: handle section symbols too */
 475             n = asm_int_expr(s1);
 476             if (n < ind)
 477                 tcc_error("attempt to .org backwards");
 478             v = 0;
 479             size = n - ind;
 480             goto zero_pad;
 481         }
 482         break;
 483     case TOK_ASM_globl:
 484     case TOK_ASM_global:
 485     case TOK_ASM_weak:
 486     tok1 = tok;
 487         do {
 488             Sym *sym;
 489
 490             next();
 491             sym = label_find(tok);
 492             if (!sym) {
 493                 sym = label_push(&s1->asm_labels, tok, 0);
 494                 sym->type.t = VT_VOID;
 495             }
 496             sym->type.t &= ~VT_STATIC;
 497             if (tok1 == TOK_ASM_weak)
 498                 sym->type.t |= VT_WEAK;
 499             next();
 500         } while (tok == ',');
 501         break;
 502     case TOK_ASM_string:
 503     case TOK_ASM_ascii:
 504     case TOK_ASM_asciz:
 505         {
 506             const uint8_t *p;
 507             int i, size, t;
 508
 509             t = tok;
 510             next();
 511             for(;;) {
 512                 if (tok != TOK_STR)
 513                     expect("string constant");
 514                 p = tokc.cstr->data;
 515                 size = tokc.cstr->size;
 516                 if (t == TOK_ASM_ascii && size > 0)
 517                     size--;
 518                 for(i = 0; i < size; i++)
 519                     g(p[i]);
 520                 next();
 521                 if (tok == ',') {
 522                     next();
 523                 } else if (tok != TOK_STR) {
 524                     break;
 525                 }
 526             }
 527         }
 528         break;
 529     case TOK_ASM_text:
 530     case TOK_ASM_data:
 531     case TOK_ASM_bss:
 532         {
 533             char sname[64];
 534             tok1 = tok;
 535             n = 0;
 536             next();
 537             if (tok != ';' && tok != TOK_LINEFEED) {
 538                 n = asm_int_expr(s1);
 539                 next();
 540             }
 541             sprintf(sname, (n?".%s%d":".%s"), get_tok_str(tok1, NULL), n);
 542             use_section(s1, sname);
 543         }
 544         break;
 545     case TOK_ASM_file:
 546         {
 547             char filename[512];
 548
 549             filename[0] = '\0';
 550             next();
 551
 552             if (tok == TOK_STR)
 553                 pstrcat(filename, sizeof(filename), tokc.cstr->data);
 554             else
 555                 pstrcat(filename, sizeof(filename), get_tok_str(tok, NULL));
 556
 557             if (s1->warn_unsupported)
 558                 tcc_warning("ignoring .file %s", filename);
 559
 560             next();
 561         }
 562         break;
 563     case TOK_ASM_ident:
 564         {
 565             char ident[256];
 566
 567             ident[0] = '\0';
 568             next();
 569
 570             if (tok == TOK_STR)
 571                 pstrcat(ident, sizeof(ident), tokc.cstr->data);
 572             else
 573                 pstrcat(ident, sizeof(ident), get_tok_str(tok, NULL));
 574
 575             if (s1->warn_unsupported)
 576                 tcc_warning("ignoring .ident %s", ident);
 577
 578             next();
 579         }
 580         break;
 581     case TOK_ASM_size:
 582         {
 583             Sym *sym;
 584
 585             next();
 586             sym = label_find(tok);
 587             if (!sym) {
 588                 tcc_error("label not found: %s", get_tok_str(tok, NULL));
 589             }
 590
 591             next();
 592             skip(',');
 593             /* XXX .size name,label2-label1 */
 594             if (s1->warn_unsupported)
 595                 tcc_warning("ignoring .size %s,*", get_tok_str(tok, NULL));
 596
 597             while (tok != '\n' && tok != CH_EOF) {
 598                 next();
 599             }
 600         }
 601         break;
 602     case TOK_ASM_type:
 603         {
 604             Sym *sym;
 605             const char *newtype;
 606
 607             next();
 608             sym = label_find(tok);
 609             if (!sym) {
 610                 sym = label_push(&s1->asm_labels, tok, 0);
 611                 sym->type.t = VT_VOID;
 612             }
 613
 614             next();
 615             skip(',');
 616             if (tok == TOK_STR) {
 617                 newtype = tokc.cstr->data;
 618             } else {
 619                 if (tok == '@' || tok == '%')
 620                     skip(tok);
 621                 newtype = get_tok_str(tok, NULL);
 622             }
 623
 624             if (!strcmp(newtype, "function") || !strcmp(newtype, "STT_FUNC")) {
 625                 sym->type.t = VT_FUNC;
 626             }
 627             else if (s1->warn_unsupported)
 628                 tcc_warning("change type of '%s' from 0x%x to '%s' ignored",
 629                     get_tok_str(sym->v, NULL), sym->type.t, newtype);
 630
 631             next();
 632         }
 633         break;
 634     case TOK_SECTION1:
 635         {
 636             char sname[256];
 637
 638             /* XXX: support more options */
 639             next();
 640             sname[0] = '\0';
 641             while (tok != ';' && tok != TOK_LINEFEED && tok != ',') {
 642                 if (tok == TOK_STR)
 643                     pstrcat(sname, sizeof(sname), tokc.cstr->data);
 644                 else
 645                     pstrcat(sname, sizeof(sname), get_tok_str(tok, NULL));
 646                 next();
 647             }
 648             if (tok == ',') {
 649                 /* skip section options */
 650                 next();
 651                 if (tok != TOK_STR)
 652                     expect("string constant");
 653                 next();
 654             }
 655             last_text_section = cur_text_section;
 656             use_section(s1, sname);
 657         }
 658         break;
 659     case TOK_ASM_previous:
 660         {
 661             Section *sec;
 662             next();
 663             if (!last_text_section)
 664                 tcc_error("no previous section referenced");
 665             sec = cur_text_section;
 666             use_section1(s1, last_text_section);
 667             last_text_section = sec;
 668         }
 669         break;
 670 #ifdef TCC_TARGET_I386
 671     case TOK_ASM_code16:
 672         {
 673             next();
 674             s1->seg_size = 16;
 675         }
 676         break;
 677     case TOK_ASM_code32:
 678         {
 679             next();
 680             s1->seg_size = 32;
 681         }
 682         break;
 683 #endif
 684 #ifdef TCC_TARGET_X86_64
 685     /* added for compatibility with GAS */
 686     case TOK_ASM_code64:
 687         next();
 688         break;
 689 #endif
 690     default:
 691         tcc_error("unknown assembler directive '.%s'", get_tok_str(tok, NULL));
 692         break;
 693     }
 694 }
 695
 696
 697 /* assemble a file */
 698 static int tcc_assemble_internal(TCCState *s1, int do_preprocess)
 699 {
 700     int opcode;
 701
 702 #if 0
 703     /* print stats about opcodes */
 704     {
 705         const ASMInstr *pa;
 706         int freq[4];
 707         int op_vals[500];
 708         int nb_op_vals, i, j;
 709
 710         nb_op_vals = 0;
 711         memset(freq, 0, sizeof(freq));
 712         for(pa = asm_instrs; pa->sym != 0; pa++) {
 713             freq[pa->nb_ops]++;
 714             for(i=0;i<pa->nb_ops;i++) {
 715                 for(j=0;j<nb_op_vals;j++) {
 716                     if (pa->op_type[i] == op_vals[j])
 717                         goto found;
 718                 }
 719                 op_vals[nb_op_vals++] = pa->op_type[i];
 720             found: ;
 721             }
 722         }
 723         for(i=0;i<nb_op_vals;i++) {
 724             int v = op_vals[i];
 725             if ((v & (v - 1)) != 0)
 726                 printf("%3d: %08x\n", i, v);
 727         }
 728         printf("size=%d nb=%d f0=%d f1=%d f2=%d f3=%d\n",
 729                sizeof(asm_instrs), sizeof(asm_instrs) / sizeof(ASMInstr),
 730                freq[0], freq[1], freq[2], freq[3]);
 731     }
 732 #endif
 733
 734     /* XXX: undefine C labels */
 735
 736     ch = file->buf_ptr[0];
 737     tok_flags = TOK_FLAG_BOL | TOK_FLAG_BOF;
 738     parse_flags = PARSE_FLAG_ASM_COMMENTS;
 739     if (do_preprocess)
 740         parse_flags |= PARSE_FLAG_PREPROCESS;
 741     next();
 742     for(;;) {
 743         if (tok == TOK_EOF)
 744             break;
 745         parse_flags |= PARSE_FLAG_LINEFEED; /* XXX: suppress that hack */
 746     redo:
 747         if (tok == '#') {
 748             /* horrible gas comment */
 749             while (tok != TOK_LINEFEED)
 750                 next();
 751         } else if (tok == '.') {
 752             asm_parse_directive(s1);
 753         } else if (tok == TOK_PPNUM) {
 754             const char *p;
 755             int n;
 756             p = tokc.cstr->data;
 757             n = strtoul(p, (char **)&p, 10);
 758             if (*p != '\0')
 759                 expect("':'");
 760             /* new local label */
 761             asm_new_label(s1, asm_get_local_label_name(s1, n), 1);
 762             next();
 763             skip(':');
 764             goto redo;
 765         } else if (tok >= TOK_IDENT) {
 766             /* instruction or label */
 767             opcode = tok;
 768             next();
 769             if (tok == ':') {
 770                 /* new label */
 771                 asm_new_label(s1, opcode, 0);
 772                 next();
 773                 goto redo;
 774             } else if (tok == '=') {
 775                 int n;
 776                 next();
 777                 n = asm_int_expr(s1);
 778                 asm_new_label1(s1, opcode, 0, SHN_ABS, n);
 779                 goto redo;
 780             } else {
 781                 asm_opcode(s1, opcode);
 782             }
 783         }
 784         /* end of line */
 785         if (tok != ';' && tok != TOK_LINEFEED){
 786             expect("end of line");
 787         }
 788         parse_flags &= ~PARSE_FLAG_LINEFEED; /* XXX: suppress that hack */
 789         next();
 790     }
 791
 792     asm_free_labels(s1);
 793
 794     return 0;
 795 }
 796
 797 /* Assemble the current file */
 798 ST_FUNC int tcc_assemble(TCCState *s1, int do_preprocess)
 799 {
 800     Sym *define_start;
 801     int ret;
 802
 803     preprocess_init(s1);
 804
 805     /* default section is text */
 806     cur_text_section = text_section;
 807     ind = cur_text_section->data_offset;
 808
 809     define_start = define_stack;
 810
 811     /* an elf symbol of type STT_FILE must be put so that STB_LOCAL
 812        symbols can be safely used */
 813     put_elf_sym(symtab_section, 0, 0,
 814                 ELFW(ST_INFO)(STB_LOCAL, STT_FILE), 0,
 815                 SHN_ABS, file->filename);
 816
 817     ret = tcc_assemble_internal(s1, do_preprocess);
 818
 819     cur_text_section->data_offset = ind;
 820
 821     free_defines(define_start);
 822
 823     return ret;
 824 }
 825
 826 /********************************************************************/
 827 /* GCC inline asm support */
 828
 829 /* assemble the string 'str' in the current C compilation unit without
 830    C preprocessing. NOTE: str is modified by modifying the '\0' at the
 831    end */
 832 static void tcc_assemble_inline(TCCState *s1, char *str, int len)
 833 {
 834     int saved_parse_flags;
 835     const int *saved_macro_ptr;
 836
 837     saved_parse_flags = parse_flags;
 838     saved_macro_ptr = macro_ptr;
 839
 840     tcc_open_bf(s1, file->filename, len);
 841     file->line_num = file->prev->line_num;
 842     memcpy(file->buffer, str, len);
 843
 844     macro_ptr = NULL;
 845     tcc_assemble_internal(s1, 0);
 846     tcc_close();
 847
 848     parse_flags = saved_parse_flags;
 849     macro_ptr = saved_macro_ptr;
 850 }
 851
 852 /* find a constraint by its number or id (gcc 3 extended
 853    syntax). return -1 if not found. Return in *pp in char after the
 854    constraint */
 855 ST_FUNC int find_constraint(ASMOperand *operands, int nb_operands,
 856                            const char *name, const char **pp)
 857 {
 858     int index;
 859     TokenSym *ts;
 860     const char *p;
 861
 862     if (isnum(*name)) {
 863         index = 0;
 864         while (isnum(*name)) {
 865             index = (index * 10) + (*name) - '0';
 866             name++;
 867         }
 868         if ((unsigned)index >= nb_operands)
 869             index = -1;
 870     } else if (*name == '[') {
 871         name++;
 872         p = strchr(name, ']');
 873         if (p) {
 874             ts = tok_alloc(name, p - name);
 875             for(index = 0; index < nb_operands; index++) {
 876                 if (operands[index].id == ts->tok)
 877                     goto found;
 878             }
 879             index = -1;
 880         found:
 881             name = p + 1;
 882         } else {
 883             index = -1;
 884         }
 885     } else {
 886         index = -1;
 887     }
 888     if (pp)
 889         *pp = name;
 890     return index;
 891 }
 892
 893 static void subst_asm_operands(ASMOperand *operands, int nb_operands,
 894                                int nb_outputs,
 895                                CString *out_str, CString *in_str)
 896 {
 897     int c, index, modifier;
 898     const char *str;
 899     ASMOperand *op;
 900     SValue sv;
 901
 902     cstr_new(out_str);
 903     str = in_str->data;
 904     for(;;) {
 905         c = *str++;
 906         if (c == '%') {
 907             if (*str == '%') {
 908                 str++;
 909                 goto add_char;
 910             }
 911             modifier = 0;
 912             if (*str == 'c' || *str == 'n' ||
 913                 *str == 'b' || *str == 'w' || *str == 'h')
 914                 modifier = *str++;
 915             index = find_constraint(operands, nb_operands, str, &str);
 916             if (index < 0)
 917                 tcc_error("invalid operand reference after %%");
 918             op = &operands[index];
 919             sv = *op->vt;
 920             if (op->reg >= 0) {
 921                 sv.r = op->reg;
 922                 if ((op->vt->r & VT_VALMASK) == VT_LLOCAL && op->is_memory)
 923                     sv.r |= VT_LVAL;
 924             }
 925             subst_asm_operand(out_str, &sv, modifier);
 926         } else {
 927         add_char:
 928             cstr_ccat(out_str, c);
 929             if (c == '\0')
 930                 break;
 931         }
 932     }
 933 }
 934
 935
 936 static void parse_asm_operands(ASMOperand *operands, int *nb_operands_ptr,
 937                                int is_output)
 938 {
 939     ASMOperand *op;
 940     int nb_operands;
 941
 942     if (tok != ':') {
 943         nb_operands = *nb_operands_ptr;
 944         for(;;) {
 945             if (nb_operands >= MAX_ASM_OPERANDS)
 946                 tcc_error("too many asm operands");
 947             op = &operands[nb_operands++];
 948             op->id = 0;
 949             if (tok == '[') {
 950                 next();
 951                 if (tok < TOK_IDENT)
 952                     expect("identifier");
 953                 op->id = tok;
 954                 next();
 955                 skip(']');
 956             }
 957             if (tok != TOK_STR)
 958                 expect("string constant");
 959             op->constraint = tcc_malloc(tokc.cstr->size);
 960             strcpy(op->constraint, tokc.cstr->data);
 961             next();
 962             skip('(');
 963             gexpr();
 964             if (is_output) {
 965                 test_lvalue();
 966             } else {
 967                 /* we want to avoid LLOCAL case, except when the 'm'
 968                    constraint is used. Note that it may come from
 969                    register storage, so we need to convert (reg)
 970                    case */
 971                 if ((vtop->r & VT_LVAL) &&
 972                     ((vtop->r & VT_VALMASK) == VT_LLOCAL ||
 973                      (vtop->r & VT_VALMASK) < VT_CONST) &&
 974                     !strchr(op->constraint, 'm')) {
 975                     gv(RC_INT);
 976                 }
 977             }
 978             op->vt = vtop;
 979             skip(')');
 980             if (tok == ',') {
 981                 next();
 982             } else {
 983                 break;
 984             }
 985         }
 986         *nb_operands_ptr = nb_operands;
 987     }
 988 }
 989
 990 /* parse the GCC asm() instruction */
 991 ST_FUNC void asm_instr(void)
 992 {
 993     CString astr, astr1;
 994     ASMOperand operands[MAX_ASM_OPERANDS];
 995     int nb_outputs, nb_operands, i, must_subst, out_reg;
 996     uint8_t clobber_regs[NB_ASM_REGS];
 997
 998     next();
 999     /* since we always generate the asm() instruction, we can ignore
1000        volatile */
1001     if (tok == TOK_VOLATILE1 || tok == TOK_VOLATILE2 || tok == TOK_VOLATILE3) {
1002         next();
1003     }
1004     parse_asm_str(&astr);
1005     nb_operands = 0;
1006     nb_outputs = 0;
1007     must_subst = 0;
1008     memset(clobber_regs, 0, sizeof(clobber_regs));
1009     if (tok == ':') {
1010         next();
1011         must_subst = 1;
1012         /* output args */
1013         parse_asm_operands(operands, &nb_operands, 1);
1014         nb_outputs = nb_operands;
1015         if (tok == ':') {
1016             next();
1017             if (tok != ')') {
1018                 /* input args */
1019                 parse_asm_operands(operands, &nb_operands, 0);
1020                 if (tok == ':') {
1021                     /* clobber list */
1022                     /* XXX: handle registers */
1023                     next();
1024                     for(;;) {
1025                         if (tok != TOK_STR)
1026                             expect("string constant");
1027                         asm_clobber(clobber_regs, tokc.cstr->data);
1028                         next();
1029                         if (tok == ',') {
1030                             next();
1031                         } else {
1032                             break;
1033                         }
1034                     }
1035                 }
1036             }
1037         }
1038     }
1039     skip(')');
1040     /* NOTE: we do not eat the ';' so that we can restore the current
1041        token after the assembler parsing */
1042     if (tok != ';')
1043         expect("';'");
1044
1045     /* save all values in the memory */
1046     save_regs(0);
1047
1048     /* compute constraints */
1049     asm_compute_constraints(operands, nb_operands, nb_outputs,
1050                             clobber_regs, &out_reg);
1051
1052     /* substitute the operands in the asm string. No substitution is
1053        done if no operands (GCC behaviour) */
1054 #ifdef ASM_DEBUG
1055     printf("asm: \"%s\"\n", (char *)astr.data);
1056 #endif
1057     if (must_subst) {
1058         subst_asm_operands(operands, nb_operands, nb_outputs, &astr1, &astr);
1059         cstr_free(&astr);
1060     } else {
1061         astr1 = astr;
1062     }
1063 #ifdef ASM_DEBUG
1064     printf("subst_asm: \"%s\"\n", (char *)astr1.data);
1065 #endif
1066
1067     /* generate loads */
1068     asm_gen_code(operands, nb_operands, nb_outputs, 0,
1069                  clobber_regs, out_reg);
1070
1071     /* assemble the string with tcc internal assembler */
1072     tcc_assemble_inline(tcc_state, astr1.data, astr1.size - 1);
1073
1074     /* restore the current C token */
1075     next();
1076
1077     /* store the output values if needed */
1078     asm_gen_code(operands, nb_operands, nb_outputs, 1,
1079                  clobber_regs, out_reg);
1080
1081     /* free everything */
1082     for(i=0;i<nb_operands;i++) {
1083         ASMOperand *op;
1084         op = &operands[i];
1085         tcc_free(op->constraint);
1086         vpop();
1087     }
1088     cstr_free(&astr1);
1089 }
1090
1091 ST_FUNC void asm_global_instr(void)
1092 {
1093     CString astr;
1094
1095     next();
1096     parse_asm_str(&astr);
1097     skip(')');
1098     /* NOTE: we do not eat the ';' so that we can restore the current
1099        token after the assembler parsing */
1100     if (tok != ';')
1101         expect("';'");
1102
1103 #ifdef ASM_DEBUG
1104     printf("asm_global: \"%s\"\n", (char *)astr.data);
1105 #endif
1106     cur_text_section = text_section;
1107     ind = cur_text_section->data_offset;
1108
1109     /* assemble the string with tcc internal assembler */
1110     tcc_assemble_inline(tcc_state, astr.data, astr.size - 1);
1111
1112     cur_text_section->data_offset = ind;
1113
1114     /* restore the current C token */
1115     next();
1116
1117     cstr_free(&astr);
1118 }
1119 #endif /* CONFIG_TCC_ASM */