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
  23 ST_FUNC int asm_get_local_label_name(TCCState *s1, unsigned int n)
  24 {
  25     char buf[64];
  26     TokenSym *ts;
  27
  28     snprintf(buf, sizeof(buf), "L..%u", n);
  29     ts = tok_alloc(buf, strlen(buf));
  30     return ts->tok;
  31 }
  32
  33 ST_FUNC void asm_expr(TCCState *s1, ExprValue *pe);
  34
  35 /* We do not use the C expression parser to handle symbols. Maybe the
  36    C expression parser could be tweaked to do so. */
  37
  38 static void asm_expr_unary(TCCState *s1, ExprValue *pe)
  39 {
  40     Sym *sym;
  41     int op, n, label;
  42     const char *p;
  43
  44     switch(tok) {
  45     case TOK_PPNUM:
  46         p = tokc.cstr->data;
  47         n = strtoul(p, (char **)&p, 0);
  48         if (*p == 'b' || *p == 'f') {
  49             /* backward or forward label */
  50             label = asm_get_local_label_name(s1, n);
  51             sym = label_find(label);
  52             if (*p == 'b') {
  53                 /* backward : find the last corresponding defined label */
  54                 if (sym && sym->r == 0)
  55                     sym = sym->prev_tok;
  56                 if (!sym)
  57                     error("local label '%d' not found backward", n);
  58             } else {
  59                 /* forward */
  60                 if (!sym || sym->r) {
  61                     /* if the last label is defined, then define a new one */
  62                     sym = label_push(&s1->asm_labels, label, 0);
  63                     sym->type.t = VT_STATIC | VT_VOID;
  64                 }
  65             }
  66             pe->v = 0;
  67             pe->sym = sym;
  68         } else if (*p == '\0') {
  69             pe->v = n;
  70             pe->sym = NULL;
  71         } else {
  72             error("invalid number syntax");
  73         }
  74         next();
  75         break;
  76     case '+':
  77         next();
  78         asm_expr_unary(s1, pe);
  79         break;
  80     case '-':
  81     case '~':
  82         op = tok;
  83         next();
  84         asm_expr_unary(s1, pe);
  85         if (pe->sym)
  86             error("invalid operation with label");
  87         if (op == '-')
  88             pe->v = -pe->v;
  89         else
  90             pe->v = ~pe->v;
  91         break;
  92     case TOK_CCHAR:
  93     case TOK_LCHAR:
  94         pe->v = tokc.i;
  95         pe->sym = NULL;
  96         next();
  97         break;
  98     case '(':
  99         next();
 100         asm_expr(s1, pe);
 101         skip(')');
 102         break;
 103     default:
 104         if (tok >= TOK_IDENT) {
 105             /* label case : if the label was not found, add one */
 106             sym = label_find(tok);
 107             if (!sym) {
 108                 sym = label_push(&s1->asm_labels, tok, 0);
 109                 /* NOTE: by default, the symbol is global */
 110                 sym->type.t = VT_VOID;
 111             }
 112             if (sym->r == SHN_ABS) {
 113                 /* if absolute symbol, no need to put a symbol value */
 114                 pe->v = sym->jnext;
 115                 pe->sym = NULL;
 116             } else {
 117                 pe->v = 0;
 118                 pe->sym = sym;
 119             }
 120             next();
 121         } else {
 122             error("bad expression syntax [%s]", get_tok_str(tok, &tokc));
 123         }
 124         break;
 125     }
 126 }
 127
 128 static void asm_expr_prod(TCCState *s1, ExprValue *pe)
 129 {
 130     int op;
 131     ExprValue e2;
 132
 133     asm_expr_unary(s1, pe);
 134     for(;;) {
 135         op = tok;
 136         if (op != '*' && op != '/' && op != '%' &&
 137             op != TOK_SHL && op != TOK_SAR)
 138             break;
 139         next();
 140         asm_expr_unary(s1, &e2);
 141         if (pe->sym || e2.sym)
 142             error("invalid operation with label");
 143         switch(op) {
 144         case '*':
 145             pe->v *= e2.v;
 146             break;
 147         case '/':
 148             if (e2.v == 0) {
 149             div_error:
 150                 error("division by zero");
 151             }
 152             pe->v /= e2.v;
 153             break;
 154         case '%':
 155             if (e2.v == 0)
 156                 goto div_error;
 157             pe->v %= e2.v;
 158             break;
 159         case TOK_SHL:
 160             pe->v <<= e2.v;
 161             break;
 162         default:
 163         case TOK_SAR:
 164             pe->v >>= e2.v;
 165             break;
 166         }
 167     }
 168 }
 169
 170 static void asm_expr_logic(TCCState *s1, ExprValue *pe)
 171 {
 172     int op;
 173     ExprValue e2;
 174
 175     asm_expr_prod(s1, pe);
 176     for(;;) {
 177         op = tok;
 178         if (op != '&' && op != '|' && op != '^')
 179             break;
 180         next();
 181         asm_expr_prod(s1, &e2);
 182         if (pe->sym || e2.sym)
 183             error("invalid operation with label");
 184         switch(op) {
 185         case '&':
 186             pe->v &= e2.v;
 187             break;
 188         case '|':
 189             pe->v |= e2.v;
 190             break;
 191         default:
 192         case '^':
 193             pe->v ^= e2.v;
 194             break;
 195         }
 196     }
 197 }
 198
 199 static inline void asm_expr_sum(TCCState *s1, ExprValue *pe)
 200 {
 201     int op;
 202     ExprValue e2;
 203
 204     asm_expr_logic(s1, pe);
 205     for(;;) {
 206         op = tok;
 207         if (op != '+' && op != '-')
 208             break;
 209         next();
 210         asm_expr_logic(s1, &e2);
 211         if (op == '+') {
 212             if (pe->sym != NULL && e2.sym != NULL)
 213                 goto cannot_relocate;
 214             pe->v += e2.v;
 215             if (pe->sym == NULL && e2.sym != NULL)
 216                 pe->sym = e2.sym;
 217         } else {
 218             pe->v -= e2.v;
 219             /* NOTE: we are less powerful than gas in that case
 220                because we store only one symbol in the expression */
 221             if (!pe->sym && !e2.sym) {
 222                 /* OK */
 223             } else if (pe->sym && !e2.sym) {
 224                 /* OK */
 225             } else if (pe->sym && e2.sym) {
 226                 if (pe->sym == e2.sym) {
 227                     /* OK */
 228                 } else if (pe->sym->r == e2.sym->r && pe->sym->r != 0) {
 229                     /* we also accept defined symbols in the same section */
 230                     pe->v += pe->sym->jnext - e2.sym->jnext;
 231                 } else {
 232                     goto cannot_relocate;
 233                 }
 234                 pe->sym = NULL; /* same symbols can be substracted to NULL */
 235             } else {
 236             cannot_relocate:
 237                 error("invalid operation with label");
 238             }
 239         }
 240     }
 241 }
 242
 243 ST_FUNC void asm_expr(TCCState *s1, ExprValue *pe)
 244 {
 245     asm_expr_sum(s1, pe);
 246 }
 247
 248 ST_FUNC int asm_int_expr(TCCState *s1)
 249 {
 250     ExprValue e;
 251     asm_expr(s1, &e);
 252     if (e.sym)
 253         expect("constant");
 254     return e.v;
 255 }
 256
 257 /* NOTE: the same name space as C labels is used to avoid using too
 258    much memory when storing labels in TokenStrings */
 259 static void asm_new_label1(TCCState *s1, int label, int is_local,
 260                            int sh_num, int value)
 261 {
 262     Sym *sym;
 263
 264     sym = label_find(label);
 265     if (sym) {
 266         if (sym->r) {
 267             /* the label is already defined */
 268             if (!is_local) {
 269                 error("assembler label '%s' already defined",
 270                       get_tok_str(label, NULL));
 271             } else {
 272                 /* redefinition of local labels is possible */
 273                 goto new_label;
 274             }
 275         }
 276     } else {
 277     new_label:
 278         sym = label_push(&s1->asm_labels, label, 0);
 279         sym->type.t = VT_STATIC | VT_VOID;
 280     }
 281     sym->r = sh_num;
 282     sym->jnext = value;
 283 }
 284
 285 static void asm_new_label(TCCState *s1, int label, int is_local)
 286 {
 287     asm_new_label1(s1, label, is_local, cur_text_section->sh_num, ind);
 288 }
 289
 290 static void asm_free_labels(TCCState *st)
 291 {
 292     Sym *s, *s1;
 293     Section *sec;
 294
 295     for(s = st->asm_labels; s != NULL; s = s1) {
 296         s1 = s->prev;
 297         /* define symbol value in object file */
 298         if (s->r) {
 299             if (s->r == SHN_ABS)
 300                 sec = SECTION_ABS;
 301             else
 302                 sec = st->sections[s->r];
 303             put_extern_sym2(s, sec, s->jnext, 0, 0);
 304         }
 305         /* remove label */
 306         table_ident[s->v - TOK_IDENT]->sym_label = NULL;
 307         sym_free(s);
 308     }
 309     st->asm_labels = NULL;
 310 }
 311
 312 static void use_section1(TCCState *s1, Section *sec)
 313 {
 314     cur_text_section->data_offset = ind;
 315     cur_text_section = sec;
 316     ind = cur_text_section->data_offset;
 317 }
 318
 319 static void use_section(TCCState *s1, const char *name)
 320 {
 321     Section *sec;
 322     sec = find_section(s1, name);
 323     use_section1(s1, sec);
 324 }
 325
 326 static void asm_parse_directive(TCCState *s1)
 327 {
 328     int n, offset, v, size, tok1;
 329     Section *sec;
 330     uint8_t *ptr;
 331
 332     /* assembler directive */
 333     next();
 334     sec = cur_text_section;
 335     switch(tok) {
 336     case TOK_ASM_align:
 337     case TOK_ASM_skip:
 338     case TOK_ASM_space:
 339         tok1 = tok;
 340         next();
 341         n = asm_int_expr(s1);
 342         if (tok1 == TOK_ASM_align) {
 343             if (n < 0 || (n & (n-1)) != 0)
 344                 error("alignment must be a positive power of two");
 345             offset = (ind + n - 1) & -n;
 346             size = offset - ind;
 347             /* the section must have a compatible alignment */
 348             if (sec->sh_addralign < n)
 349                 sec->sh_addralign = n;
 350         } else {
 351             size = n;
 352         }
 353         v = 0;
 354         if (tok == ',') {
 355             next();
 356             v = asm_int_expr(s1);
 357         }
 358     zero_pad:
 359         if (sec->sh_type != SHT_NOBITS) {
 360             sec->data_offset = ind;
 361             ptr = section_ptr_add(sec, size);
 362             memset(ptr, v, size);
 363         }
 364         ind += size;
 365         break;
 366     case TOK_ASM_quad:
 367         next();
 368         for(;;) {
 369             uint64_t vl;
 370             const char *p;
 371
 372             p = tokc.cstr->data;
 373             if (tok != TOK_PPNUM) {
 374             error_constant:
 375                 error("64 bit constant");
 376             }
 377             vl = strtoll(p, (char **)&p, 0);
 378             if (*p != '\0')
 379                 goto error_constant;
 380             next();
 381             if (sec->sh_type != SHT_NOBITS) {
 382                 /* XXX: endianness */
 383                 gen_le32(vl);
 384                 gen_le32(vl >> 32);
 385             } else {
 386                 ind += 8;
 387             }
 388             if (tok != ',')
 389                 break;
 390             next();
 391         }
 392         break;
 393     case TOK_ASM_byte:
 394         size = 1;
 395         goto asm_data;
 396     case TOK_ASM_word:
 397     case TOK_SHORT:
 398         size = 2;
 399         goto asm_data;
 400     case TOK_LONG:
 401     case TOK_INT:
 402         size = 4;
 403     asm_data:
 404         next();
 405         for(;;) {
 406             ExprValue e;
 407             asm_expr(s1, &e);
 408             if (sec->sh_type != SHT_NOBITS) {
 409                 if (size == 4) {
 410                     gen_expr32(&e);
 411                 } else {
 412                     if (e.sym)
 413                         expect("constant");
 414                     if (size == 1)
 415                         g(e.v);
 416                     else
 417                         gen_le16(e.v);
 418                 }
 419             } else {
 420                 ind += size;
 421             }
 422             if (tok != ',')
 423                 break;
 424             next();
 425         }
 426         break;
 427     case TOK_ASM_fill:
 428         {
 429             int repeat, size, val, i, j;
 430             uint8_t repeat_buf[8];
 431             next();
 432             repeat = asm_int_expr(s1);
 433             if (repeat < 0) {
 434                 error("repeat < 0; .fill ignored");
 435                 break;
 436             }
 437             size = 1;
 438             val = 0;
 439             if (tok == ',') {
 440                 next();
 441                 size = asm_int_expr(s1);
 442                 if (size < 0) {
 443                     error("size < 0; .fill ignored");
 444                     break;
 445                 }
 446                 if (size > 8)
 447                     size = 8;
 448                 if (tok == ',') {
 449                     next();
 450                     val = asm_int_expr(s1);
 451                 }
 452             }
 453             /* XXX: endianness */
 454             repeat_buf[0] = val;
 455             repeat_buf[1] = val >> 8;
 456             repeat_buf[2] = val >> 16;
 457             repeat_buf[3] = val >> 24;
 458             repeat_buf[4] = 0;
 459             repeat_buf[5] = 0;
 460             repeat_buf[6] = 0;
 461             repeat_buf[7] = 0;
 462             for(i = 0; i < repeat; i++) {
 463                 for(j = 0; j < size; j++) {
 464                     g(repeat_buf[j]);
 465                 }
 466             }
 467         }
 468         break;
 469     case TOK_ASM_org:
 470         {
 471             unsigned long n;
 472             next();
 473             /* XXX: handle section symbols too */
 474             n = asm_int_expr(s1);
 475             if (n < ind)
 476                 error("attempt to .org backwards");
 477             v = 0;
 478             size = n - ind;
 479             goto zero_pad;
 480         }
 481         break;
 482     case TOK_ASM_globl:
 483     case TOK_ASM_global:
 484         {
 485             Sym *sym;
 486
 487             next();
 488             sym = label_find(tok);
 489             if (!sym) {
 490                 sym = label_push(&s1->asm_labels, tok, 0);
 491                 sym->type.t = VT_VOID;
 492             }
 493             sym->type.t &= ~VT_STATIC;
 494             next();
 495         }
 496         break;
 497     case TOK_ASM_string:
 498     case TOK_ASM_ascii:
 499     case TOK_ASM_asciz:
 500         {
 501             const uint8_t *p;
 502             int i, size, t;
 503
 504             t = tok;
 505             next();
 506             for(;;) {
 507                 if (tok != TOK_STR)
 508                     expect("string constant");
 509                 p = tokc.cstr->data;
 510                 size = tokc.cstr->size;
 511                 if (t == TOK_ASM_ascii && size > 0)
 512                     size--;
 513                 for(i = 0; i < size; i++)
 514                     g(p[i]);
 515                 next();
 516                 if (tok == ',') {
 517                     next();
 518                 } else if (tok != TOK_STR) {
 519                     break;
 520                 }
 521             }
 522         }
 523         break;
 524     case TOK_ASM_text:
 525     case TOK_ASM_data:
 526     case TOK_ASM_bss:
 527         {
 528             char sname[64];
 529             tok1 = tok;
 530             n = 0;
 531             next();
 532             if (tok != ';' && tok != TOK_LINEFEED) {
 533                 n = asm_int_expr(s1);
 534                 next();
 535             }
 536             sprintf(sname, (n?".%s%d":".%s"), get_tok_str(tok1, NULL), n);
 537             use_section(s1, sname);
 538         }
 539         break;
 540     case TOK_ASM_file:
 541         {
 542             char filename[512];
 543
 544             filename[0] = '\0';
 545             next();
 546
 547             if (tok == TOK_STR)
 548                 pstrcat(filename, sizeof(filename), tokc.cstr->data);
 549             else
 550                 pstrcat(filename, sizeof(filename), get_tok_str(tok, NULL));
 551
 552             if (s1->warn_unsupported)
 553                 warning("ignoring .file %s", filename);
 554
 555             next();
 556         }
 557         break;
 558     case TOK_ASM_ident:
 559         {
 560             char ident[256];
 561
 562             ident[0] = '\0';
 563             next();
 564
 565             if (tok == TOK_STR)
 566                 pstrcat(ident, sizeof(ident), tokc.cstr->data);
 567             else
 568                 pstrcat(ident, sizeof(ident), get_tok_str(tok, NULL));
 569
 570             if (s1->warn_unsupported)
 571                 warning("ignoring .ident %s", ident);
 572
 573             next();
 574         }
 575         break;
 576     case TOK_ASM_size:
 577         {
 578             Sym *sym;
 579
 580             next();
 581             sym = label_find(tok);
 582             if (!sym) {
 583                 error("label not found: %s", get_tok_str(tok, NULL));
 584             }
 585
 586             next();
 587             skip(',');
 588             /* XXX .size name,label2-label1 */
 589             if (s1->warn_unsupported)
 590                 warning("ignoring .size %s,*", get_tok_str(tok, NULL));
 591
 592             while (tok != '\n' && tok != CH_EOF) {
 593                 next();
 594             }
 595         }
 596         break;
 597     case TOK_ASM_type:
 598         {
 599             Sym *sym;
 600             char newtype[64];
 601             newtype[0] = 0;
 602
 603             next();
 604             sym = label_find(tok);
 605             if (!sym) {
 606                 sym = label_push(&s1->asm_labels, tok, 0);
 607                 sym->type.t = VT_VOID;
 608             }
 609
 610             next();
 611             skip(',');
 612             skip('@');
 613             if (tok == TOK_STR)
 614                 pstrcat(newtype, sizeof(newtype), tokc.cstr->data);
 615             else
 616                 pstrcat(newtype, sizeof(newtype), get_tok_str(tok, NULL));
 617
 618             if (!strcmp(newtype, "function")) {
 619                 sym->type.t = VT_FUNC;
 620             }
 621             else if (s1->warn_unsupported)
 622                 warning("change type of '%s' from 0x%x to '%s' ignored",
 623                     get_tok_str(sym->v, NULL), sym->type.t, newtype);
 624
 625             next();
 626         }
 627         break;
 628     case TOK_SECTION1:
 629         {
 630             char sname[256];
 631
 632             /* XXX: support more options */
 633             next();
 634             sname[0] = '\0';
 635             while (tok != ';' && tok != TOK_LINEFEED && tok != ',') {
 636                 if (tok == TOK_STR)
 637                     pstrcat(sname, sizeof(sname), tokc.cstr->data);
 638                 else
 639                     pstrcat(sname, sizeof(sname), get_tok_str(tok, NULL));
 640                 next();
 641             }
 642             if (tok == ',') {
 643                 /* skip section options */
 644                 next();
 645                 if (tok != TOK_STR)
 646                     expect("string constant");
 647                 next();
 648             }
 649             last_text_section = cur_text_section;
 650             use_section(s1, sname);
 651         }
 652         break;
 653     case TOK_ASM_previous:
 654         {
 655             Section *sec;
 656             next();
 657             if (!last_text_section)
 658                 error("no previous section referenced");
 659             sec = cur_text_section;
 660             use_section1(s1, last_text_section);
 661             last_text_section = sec;
 662         }
 663         break;
 664 #ifdef TCC_TARGET_I386
 665     case TOK_ASM_code16:
 666         {
 667             next();
 668             s1->seg_size = 16;
 669         }
 670         break;
 671     case TOK_ASM_code32:
 672         {
 673             next();
 674             s1->seg_size = 32;
 675         }
 676         break;
 677 #endif
 678 #ifdef TCC_TARGET_X86_64
 679     /* added for compatibility with GAS */
 680     case TOK_ASM_code64:
 681         next();
 682         break;
 683 #endif
 684     default:
 685         error("unknown assembler directive '.%s'", get_tok_str(tok, NULL));
 686         break;
 687     }
 688 }
 689
 690
 691 /* assemble a file */
 692 static int tcc_assemble_internal(TCCState *s1, int do_preprocess)
 693 {
 694     int opcode;
 695
 696 #if 0
 697     /* print stats about opcodes */
 698     {
 699         const ASMInstr *pa;
 700         int freq[4];
 701         int op_vals[500];
 702         int nb_op_vals, i, j;
 703
 704         nb_op_vals = 0;
 705         memset(freq, 0, sizeof(freq));
 706         for(pa = asm_instrs; pa->sym != 0; pa++) {
 707             freq[pa->nb_ops]++;
 708             for(i=0;i<pa->nb_ops;i++) {
 709                 for(j=0;j<nb_op_vals;j++) {
 710                     if (pa->op_type[i] == op_vals[j])
 711                         goto found;
 712                 }
 713                 op_vals[nb_op_vals++] = pa->op_type[i];
 714             found: ;
 715             }
 716         }
 717         for(i=0;i<nb_op_vals;i++) {
 718             int v = op_vals[i];
 719             if ((v & (v - 1)) != 0)
 720                 printf("%3d: %08x\n", i, v);
 721         }
 722         printf("size=%d nb=%d f0=%d f1=%d f2=%d f3=%d\n",
 723                sizeof(asm_instrs), sizeof(asm_instrs) / sizeof(ASMInstr),
 724                freq[0], freq[1], freq[2], freq[3]);
 725     }
 726 #endif
 727
 728     /* XXX: undefine C labels */
 729
 730     ch = file->buf_ptr[0];
 731     tok_flags = TOK_FLAG_BOL | TOK_FLAG_BOF;
 732     parse_flags = PARSE_FLAG_ASM_COMMENTS;
 733     if (do_preprocess)
 734         parse_flags |= PARSE_FLAG_PREPROCESS;
 735     next();
 736     for(;;) {
 737         if (tok == TOK_EOF)
 738             break;
 739         parse_flags |= PARSE_FLAG_LINEFEED; /* XXX: suppress that hack */
 740     redo:
 741         if (tok == '#') {
 742             /* horrible gas comment */
 743             while (tok != TOK_LINEFEED)
 744                 next();
 745         } else if (tok == '.') {
 746             asm_parse_directive(s1);
 747         } else if (tok == TOK_PPNUM) {
 748             const char *p;
 749             int n;
 750             p = tokc.cstr->data;
 751             n = strtoul(p, (char **)&p, 10);
 752             if (*p != '\0')
 753                 expect("':'");
 754             /* new local label */
 755             asm_new_label(s1, asm_get_local_label_name(s1, n), 1);
 756             next();
 757             skip(':');
 758             goto redo;
 759         } else if (tok >= TOK_IDENT) {
 760             /* instruction or label */
 761             opcode = tok;
 762             next();
 763             if (tok == ':') {
 764                 /* new label */
 765                 asm_new_label(s1, opcode, 0);
 766                 next();
 767                 goto redo;
 768             } else if (tok == '=') {
 769                 int n;
 770                 next();
 771                 n = asm_int_expr(s1);
 772                 asm_new_label1(s1, opcode, 0, SHN_ABS, n);
 773                 goto redo;
 774             } else {
 775                 asm_opcode(s1, opcode);
 776             }
 777         }
 778         /* end of line */
 779         if (tok != ';' && tok != TOK_LINEFEED){
 780             expect("end of line");
 781         }
 782         parse_flags &= ~PARSE_FLAG_LINEFEED; /* XXX: suppress that hack */
 783         next();
 784     }
 785
 786     asm_free_labels(s1);
 787
 788     return 0;
 789 }
 790
 791 /* Assemble the current file */
 792 ST_FUNC int tcc_assemble(TCCState *s1, int do_preprocess)
 793 {
 794     Sym *define_start;
 795     int ret;
 796
 797     preprocess_init(s1);
 798
 799     /* default section is text */
 800     cur_text_section = text_section;
 801     ind = cur_text_section->data_offset;
 802
 803     define_start = define_stack;
 804
 805     /* an elf symbol of type STT_FILE must be put so that STB_LOCAL
 806        symbols can be safely used */
 807     put_elf_sym(symtab_section, 0, 0,
 808                 ELFW(ST_INFO)(STB_LOCAL, STT_FILE), 0,
 809                 SHN_ABS, file->filename);
 810
 811     ret = tcc_assemble_internal(s1, do_preprocess);
 812
 813     cur_text_section->data_offset = ind;
 814
 815     free_defines(define_start);
 816
 817     return ret;
 818 }
 819
 820 /********************************************************************/
 821 /* GCC inline asm support */
 822
 823 /* assemble the string 'str' in the current C compilation unit without
 824    C preprocessing. NOTE: str is modified by modifying the '\0' at the
 825    end */
 826 static void tcc_assemble_inline(TCCState *s1, char *str, int len)
 827 {
 828     BufferedFile *bf, *saved_file;
 829     int saved_parse_flags;
 830     const int *saved_macro_ptr;
 831
 832     bf = tcc_malloc(sizeof(BufferedFile));
 833     memset(bf, 0, sizeof(BufferedFile));
 834     bf->fd = -1;
 835     bf->buf_ptr = str;
 836     bf->buf_end = str + len;
 837     str[len] = CH_EOB;
 838     /* same name as current file so that errors are correctly
 839        reported */
 840     pstrcpy(bf->filename, sizeof(bf->filename), file->filename);
 841     bf->line_num = file->line_num;
 842     saved_file = file;
 843     file = bf;
 844     saved_parse_flags = parse_flags;
 845     saved_macro_ptr = macro_ptr;
 846     macro_ptr = NULL;
 847
 848     tcc_assemble_internal(s1, 0);
 849
 850     parse_flags = saved_parse_flags;
 851     macro_ptr = saved_macro_ptr;
 852     file = saved_file;
 853     tcc_free(bf);
 854 }
 855
 856 /* find a constraint by its number or id (gcc 3 extended
 857    syntax). return -1 if not found. Return in *pp in char after the
 858    constraint */
 859 ST_FUNC int find_constraint(ASMOperand *operands, int nb_operands,
 860                            const char *name, const char **pp)
 861 {
 862     int index;
 863     TokenSym *ts;
 864     const char *p;
 865
 866     if (isnum(*name)) {
 867         index = 0;
 868         while (isnum(*name)) {
 869             index = (index * 10) + (*name) - '0';
 870             name++;
 871         }
 872         if ((unsigned)index >= nb_operands)
 873             index = -1;
 874     } else if (*name == '[') {
 875         name++;
 876         p = strchr(name, ']');
 877         if (p) {
 878             ts = tok_alloc(name, p - name);
 879             for(index = 0; index < nb_operands; index++) {
 880                 if (operands[index].id == ts->tok)
 881                     goto found;
 882             }
 883             index = -1;
 884         found:
 885             name = p + 1;
 886         } else {
 887             index = -1;
 888         }
 889     } else {
 890         index = -1;
 891     }
 892     if (pp)
 893         *pp = name;
 894     return index;
 895 }
 896
 897 static void subst_asm_operands(ASMOperand *operands, int nb_operands,
 898                                int nb_outputs,
 899                                CString *out_str, CString *in_str)
 900 {
 901     int c, index, modifier;
 902     const char *str;
 903     ASMOperand *op;
 904     SValue sv;
 905
 906     cstr_new(out_str);
 907     str = in_str->data;
 908     for(;;) {
 909         c = *str++;
 910         if (c == '%') {
 911             if (*str == '%') {
 912                 str++;
 913                 goto add_char;
 914             }
 915             modifier = 0;
 916             if (*str == 'c' || *str == 'n' ||
 917                 *str == 'b' || *str == 'w' || *str == 'h')
 918                 modifier = *str++;
 919             index = find_constraint(operands, nb_operands, str, &str);
 920             if (index < 0)
 921                 error("invalid operand reference after %%");
 922             op = &operands[index];
 923             sv = *op->vt;
 924             if (op->reg >= 0) {
 925                 sv.r = op->reg;
 926                 if ((op->vt->r & VT_VALMASK) == VT_LLOCAL && op->is_memory)
 927                     sv.r |= VT_LVAL;
 928             }
 929             subst_asm_operand(out_str, &sv, modifier);
 930         } else {
 931         add_char:
 932             cstr_ccat(out_str, c);
 933             if (c == '\0')
 934                 break;
 935         }
 936     }
 937 }
 938
 939
 940 static void parse_asm_operands(ASMOperand *operands, int *nb_operands_ptr,
 941                                int is_output)
 942 {
 943     ASMOperand *op;
 944     int nb_operands;
 945
 946     if (tok != ':') {
 947         nb_operands = *nb_operands_ptr;
 948         for(;;) {
 949             if (nb_operands >= MAX_ASM_OPERANDS)
 950                 error("too many asm operands");
 951             op = &operands[nb_operands++];
 952             op->id = 0;
 953             if (tok == '[') {
 954                 next();
 955                 if (tok < TOK_IDENT)
 956                     expect("identifier");
 957                 op->id = tok;
 958                 next();
 959                 skip(']');
 960             }
 961             if (tok != TOK_STR)
 962                 expect("string constant");
 963             op->constraint = tcc_malloc(tokc.cstr->size);
 964             strcpy(op->constraint, tokc.cstr->data);
 965             next();
 966             skip('(');
 967             gexpr();
 968             if (is_output) {
 969                 test_lvalue();
 970             } else {
 971                 /* we want to avoid LLOCAL case, except when the 'm'
 972                    constraint is used. Note that it may come from
 973                    register storage, so we need to convert (reg)
 974                    case */
 975                 if ((vtop->r & VT_LVAL) &&
 976                     ((vtop->r & VT_VALMASK) == VT_LLOCAL ||
 977                      (vtop->r & VT_VALMASK) < VT_CONST) &&
 978                     !strchr(op->constraint, 'm')) {
 979                     gv(RC_INT);
 980                 }
 981             }
 982             op->vt = vtop;
 983             skip(')');
 984             if (tok == ',') {
 985                 next();
 986             } else {
 987                 break;
 988             }
 989         }
 990         *nb_operands_ptr = nb_operands;
 991     }
 992 }
 993
 994 /* parse the GCC asm() instruction */
 995 ST_FUNC void asm_instr(void)
 996 {
 997     CString astr, astr1;
 998     ASMOperand operands[MAX_ASM_OPERANDS];
 999     int nb_inputs, nb_outputs, nb_operands, i, must_subst, out_reg;
1000     uint8_t clobber_regs[NB_ASM_REGS];
1001
1002     next();
1003     /* since we always generate the asm() instruction, we can ignore
1004        volatile */
1005     if (tok == TOK_VOLATILE1 || tok == TOK_VOLATILE2 || tok == TOK_VOLATILE3) {
1006         next();
1007     }
1008     parse_asm_str(&astr);
1009     nb_operands = 0;
1010     nb_outputs = 0;
1011     must_subst = 0;
1012     memset(clobber_regs, 0, sizeof(clobber_regs));
1013     if (tok == ':') {
1014         next();
1015         must_subst = 1;
1016         /* output args */
1017         parse_asm_operands(operands, &nb_operands, 1);
1018         nb_outputs = nb_operands;
1019         if (tok == ':') {
1020             next();
1021             if (tok != ')') {
1022                 /* input args */
1023                 parse_asm_operands(operands, &nb_operands, 0);
1024                 if (tok == ':') {
1025                     /* clobber list */
1026                     /* XXX: handle registers */
1027                     next();
1028                     for(;;) {
1029                         if (tok != TOK_STR)
1030                             expect("string constant");
1031                         asm_clobber(clobber_regs, tokc.cstr->data);
1032                         next();
1033                         if (tok == ',') {
1034                             next();
1035                         } else {
1036                             break;
1037                         }
1038                     }
1039                 }
1040             }
1041         }
1042     }
1043     skip(')');
1044     /* NOTE: we do not eat the ';' so that we can restore the current
1045        token after the assembler parsing */
1046     if (tok != ';')
1047         expect("';'");
1048     nb_inputs = nb_operands - nb_outputs;
1049
1050     /* save all values in the memory */
1051     save_regs(0);
1052
1053     /* compute constraints */
1054     asm_compute_constraints(operands, nb_operands, nb_outputs,
1055                             clobber_regs, &out_reg);
1056
1057     /* substitute the operands in the asm string. No substitution is
1058        done if no operands (GCC behaviour) */
1059 #ifdef ASM_DEBUG
1060     printf("asm: \"%s\"\n", (char *)astr.data);
1061 #endif
1062     if (must_subst) {
1063         subst_asm_operands(operands, nb_operands, nb_outputs, &astr1, &astr);
1064         cstr_free(&astr);
1065     } else {
1066         astr1 = astr;
1067     }
1068 #ifdef ASM_DEBUG
1069     printf("subst_asm: \"%s\"\n", (char *)astr1.data);
1070 #endif
1071
1072     /* generate loads */
1073     asm_gen_code(operands, nb_operands, nb_outputs, 0,
1074                  clobber_regs, out_reg);
1075
1076     /* assemble the string with tcc internal assembler */
1077     tcc_assemble_inline(tcc_state, astr1.data, astr1.size - 1);
1078
1079     /* restore the current C token */
1080     next();
1081
1082     /* store the output values if needed */
1083     asm_gen_code(operands, nb_operands, nb_outputs, 1,
1084                  clobber_regs, out_reg);
1085
1086     /* free everything */
1087     for(i=0;i<nb_operands;i++) {
1088         ASMOperand *op;
1089         op = &operands[i];
1090         tcc_free(op->constraint);
1091         vpop();
1092     }
1093     cstr_free(&astr1);
1094 }
1095
1096 ST_FUNC void asm_global_instr(void)
1097 {
1098     CString astr;
1099
1100     next();
1101     parse_asm_str(&astr);
1102     skip(')');
1103     /* NOTE: we do not eat the ';' so that we can restore the current
1104        token after the assembler parsing */
1105     if (tok != ';')
1106         expect("';'");
1107
1108 #ifdef ASM_DEBUG
1109     printf("asm_global: \"%s\"\n", (char *)astr.data);
1110 #endif
1111     cur_text_section = text_section;
1112     ind = cur_text_section->data_offset;
1113
1114     /* assemble the string with tcc internal assembler */
1115     tcc_assemble_inline(tcc_state, astr.data, astr.size - 1);
1116
1117     cur_text_section->data_offset = ind;
1118
1119     /* restore the current C token */
1120     next();
1121
1122     cstr_free(&astr);
1123 }