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 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                     tcc_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             tcc_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             tcc_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             tcc_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             tcc_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                 tcc_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             tcc_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 subtracted to NULL */
 235             } else {
 236             cannot_relocate:
 237                 tcc_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                 tcc_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                 tcc_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                 tcc_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                 tcc_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                     tcc_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                 tcc_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     case TOK_ASM_weak:
 485         case TOK_ASM_hidden:
 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             if (tok1 != TOK_ASM_hidden)
 497                 sym->type.t &= ~VT_STATIC;
 498             if (tok1 == TOK_ASM_weak)
 499                 sym->type.t |= VT_WEAK;
 500                         else if (tok1 == TOK_ASM_hidden)
 501                                 sym->type.t |= STV_HIDDEN << VT_VIS_SHIFT;
 502             next();
 503         } while (tok == ',');
 504         break;
 505     case TOK_ASM_string:
 506     case TOK_ASM_ascii:
 507     case TOK_ASM_asciz:
 508         {
 509             const uint8_t *p;
 510             int i, size, t;
 511
 512             t = tok;
 513             next();
 514             for(;;) {
 515                 if (tok != TOK_STR)
 516                     expect("string constant");
 517                 p = tokc.cstr->data;
 518                 size = tokc.cstr->size;
 519                 if (t == TOK_ASM_ascii && size > 0)
 520                     size--;
 521                 for(i = 0; i < size; i++)
 522                     g(p[i]);
 523                 next();
 524                 if (tok == ',') {
 525                     next();
 526                 } else if (tok != TOK_STR) {
 527                     break;
 528                 }
 529             }
 530         }
 531         break;
 532     case TOK_ASM_text:
 533     case TOK_ASM_data:
 534     case TOK_ASM_bss:
 535         {
 536             char sname[64];
 537             tok1 = tok;
 538             n = 0;
 539             next();
 540             if (tok != ';' && tok != TOK_LINEFEED) {
 541                 n = asm_int_expr(s1);
 542                 next();
 543             }
 544             sprintf(sname, (n?".%s%d":".%s"), get_tok_str(tok1, NULL), n);
 545             use_section(s1, sname);
 546         }
 547         break;
 548     case TOK_ASM_file:
 549         {
 550             char filename[512];
 551
 552             filename[0] = '\0';
 553             next();
 554
 555             if (tok == TOK_STR)
 556                 pstrcat(filename, sizeof(filename), tokc.cstr->data);
 557             else
 558                 pstrcat(filename, sizeof(filename), get_tok_str(tok, NULL));
 559
 560             if (s1->warn_unsupported)
 561                 tcc_warning("ignoring .file %s", filename);
 562
 563             next();
 564         }
 565         break;
 566     case TOK_ASM_ident:
 567         {
 568             char ident[256];
 569
 570             ident[0] = '\0';
 571             next();
 572
 573             if (tok == TOK_STR)
 574                 pstrcat(ident, sizeof(ident), tokc.cstr->data);
 575             else
 576                 pstrcat(ident, sizeof(ident), get_tok_str(tok, NULL));
 577
 578             if (s1->warn_unsupported)
 579                 tcc_warning("ignoring .ident %s", ident);
 580
 581             next();
 582         }
 583         break;
 584     case TOK_ASM_size:
 585         {
 586             Sym *sym;
 587
 588             next();
 589             sym = label_find(tok);
 590             if (!sym) {
 591                 tcc_error("label not found: %s", get_tok_str(tok, NULL));
 592             }
 593
 594             /* XXX .size name,label2-label1 */
 595             if (s1->warn_unsupported)
 596                 tcc_warning("ignoring .size %s,*", get_tok_str(tok, NULL));
 597
 598             next();
 599             skip(',');
 600             while (tok != '\n' && tok != CH_EOF) {
 601                 next();
 602             }
 603         }
 604         break;
 605     case TOK_ASM_type:
 606         {
 607             Sym *sym;
 608             const char *newtype;
 609
 610             next();
 611             sym = label_find(tok);
 612             if (!sym) {
 613                 sym = label_push(&s1->asm_labels, tok, 0);
 614                 sym->type.t = VT_VOID;
 615             }
 616
 617             next();
 618             skip(',');
 619             if (tok == TOK_STR) {
 620                 newtype = tokc.cstr->data;
 621             } else {
 622                 if (tok == '@' || tok == '%')
 623                     skip(tok);
 624                 newtype = get_tok_str(tok, NULL);
 625             }
 626
 627             if (!strcmp(newtype, "function") || !strcmp(newtype, "STT_FUNC")) {
 628                 sym->type.t = (sym->type.t & ~VT_BTYPE) | VT_FUNC;
 629             }
 630             else if (s1->warn_unsupported)
 631                 tcc_warning("change type of '%s' from 0x%x to '%s' ignored",
 632                     get_tok_str(sym->v, NULL), sym->type.t, newtype);
 633
 634             next();
 635         }
 636         break;
 637     case TOK_SECTION1:
 638         {
 639             char sname[256];
 640
 641             /* XXX: support more options */
 642             next();
 643             sname[0] = '\0';
 644             while (tok != ';' && tok != TOK_LINEFEED && tok != ',') {
 645                 if (tok == TOK_STR)
 646                     pstrcat(sname, sizeof(sname), tokc.cstr->data);
 647                 else
 648                     pstrcat(sname, sizeof(sname), get_tok_str(tok, NULL));
 649                 next();
 650             }
 651             if (tok == ',') {
 652                 /* skip section options */
 653                 next();
 654                 if (tok != TOK_STR)
 655                     expect("string constant");
 656                 next();
 657             }
 658             last_text_section = cur_text_section;
 659             use_section(s1, sname);
 660         }
 661         break;
 662     case TOK_ASM_previous:
 663         {
 664             Section *sec;
 665             next();
 666             if (!last_text_section)
 667                 tcc_error("no previous section referenced");
 668             sec = cur_text_section;
 669             use_section1(s1, last_text_section);
 670             last_text_section = sec;
 671         }
 672         break;
 673 #ifdef TCC_TARGET_I386
 674     case TOK_ASM_code16:
 675         {
 676             next();
 677             s1->seg_size = 16;
 678         }
 679         break;
 680     case TOK_ASM_code32:
 681         {
 682             next();
 683             s1->seg_size = 32;
 684         }
 685         break;
 686 #endif
 687 #ifdef TCC_TARGET_X86_64
 688     /* added for compatibility with GAS */
 689     case TOK_ASM_code64:
 690         next();
 691         break;
 692 #endif
 693     default:
 694         tcc_error("unknown assembler directive '.%s'", get_tok_str(tok, NULL));
 695         break;
 696     }
 697 }
 698
 699 /* assemble a file */
 700 static int tcc_assemble_internal(TCCState *s1, int do_preprocess)
 701 {
 702     int opcode;
 703
 704 #ifdef PRINTF_ASM_CODE
 705         ST_FUNC void printf_asm_opcode();
 706     /* print stats about opcodes */
 707         printf_asm_opcode();
 708 #endif
 709
 710     /* XXX: undefine C labels */
 711
 712     ch = file->buf_ptr[0];
 713     tok_flags = TOK_FLAG_BOL | TOK_FLAG_BOF;
 714     parse_flags = PARSE_FLAG_ASM_COMMENTS;
 715     if (do_preprocess)
 716         parse_flags |= PARSE_FLAG_PREPROCESS;
 717     next();
 718     for(;;) {
 719         if (tok == TOK_EOF)
 720             break;
 721         parse_flags |= PARSE_FLAG_LINEFEED; /* XXX: suppress that hack */
 722     redo:
 723         if (tok == '#') {
 724             /* horrible gas comment */
 725             while (tok != TOK_LINEFEED)
 726                 next();
 727         } else if (tok == '.') {
 728             asm_parse_directive(s1);
 729         } else if (tok == TOK_PPNUM) {
 730             const char *p;
 731             int n;
 732             p = tokc.cstr->data;
 733             n = strtoul(p, (char **)&p, 10);
 734             if (*p != '\0')
 735                 expect("':'");
 736             /* new local label */
 737             asm_new_label(s1, asm_get_local_label_name(s1, n), 1);
 738             next();
 739             skip(':');
 740             goto redo;
 741         } else if (tok >= TOK_IDENT) {
 742             /* instruction or label */
 743             opcode = tok;
 744             next();
 745             if (tok == ':') {
 746                 /* new label */
 747                 asm_new_label(s1, opcode, 0);
 748                 next();
 749                 goto redo;
 750             } else if (tok == '=') {
 751                 int n;
 752                 next();
 753                 n = asm_int_expr(s1);
 754                 asm_new_label1(s1, opcode, 0, SHN_ABS, n);
 755                 goto redo;
 756             } else {
 757                 asm_opcode(s1, opcode);
 758             }
 759         }
 760         /* end of line */
 761         if (tok != ';' && tok != TOK_LINEFEED){
 762             expect("end of line");
 763         }
 764         parse_flags &= ~PARSE_FLAG_LINEFEED; /* XXX: suppress that hack */
 765         next();
 766     }
 767
 768     asm_free_labels(s1);
 769
 770     return 0;
 771 }
 772
 773 /* Assemble the current file */
 774 ST_FUNC int tcc_assemble(TCCState *s1, int do_preprocess)
 775 {
 776     Sym *define_start;
 777     int ret;
 778
 779     preprocess_init(s1);
 780
 781     /* default section is text */
 782     cur_text_section = text_section;
 783     ind = cur_text_section->data_offset;
 784
 785     define_start = define_stack;
 786
 787     /* an elf symbol of type STT_FILE must be put so that STB_LOCAL
 788        symbols can be safely used */
 789     put_elf_sym(symtab_section, 0, 0, ELFW(ST_INFO)(STB_LOCAL, STT_FILE), 0,
 790                 SHN_ABS, file->filename);
 791
 792     ret = tcc_assemble_internal(s1, do_preprocess);
 793
 794     cur_text_section->data_offset = ind;
 795
 796     free_defines(define_start);
 797
 798     return ret;
 799 }
 800
 801 /********************************************************************/
 802 /* GCC inline asm support */
 803
 804 /* assemble the string 'str' in the current C compilation unit without
 805    C preprocessing. NOTE: str is modified by modifying the '\0' at the
 806    end */
 807 static void tcc_assemble_inline(TCCState *s1, char *str, int len)
 808 {
 809     int saved_parse_flags;
 810     const int *saved_macro_ptr;
 811
 812     saved_parse_flags = parse_flags;
 813     saved_macro_ptr = macro_ptr;
 814
 815     tcc_open_bf(s1, ":asm:", len);
 816     memcpy(file->buffer, str, len);
 817
 818     macro_ptr = NULL;
 819     tcc_assemble_internal(s1, 0);
 820     tcc_close();
 821
 822     parse_flags = saved_parse_flags;
 823     macro_ptr = saved_macro_ptr;
 824 }
 825
 826 /* find a constraint by its number or id (gcc 3 extended
 827    syntax). return -1 if not found. Return in *pp in char after the
 828    constraint */
 829 ST_FUNC int find_constraint(ASMOperand *operands, int nb_operands,
 830                            const char *name, const char **pp)
 831 {
 832     int index;
 833     TokenSym *ts;
 834     const char *p;
 835
 836     if (isnum(*name)) {
 837         index = 0;
 838         while (isnum(*name)) {
 839             index = (index * 10) + (*name) - '0';
 840             name++;
 841         }
 842         if ((unsigned)index >= nb_operands)
 843             index = -1;
 844     } else if (*name == '[') {
 845         name++;
 846         p = strchr(name, ']');
 847         if (p) {
 848             ts = tok_alloc(name, p - name);
 849             for(index = 0; index < nb_operands; index++) {
 850                 if (operands[index].id == ts->tok)
 851                     goto found;
 852             }
 853             index = -1;
 854         found:
 855             name = p + 1;
 856         } else {
 857             index = -1;
 858         }
 859     } else {
 860         index = -1;
 861     }
 862     if (pp)
 863         *pp = name;
 864     return index;
 865 }
 866
 867 static void subst_asm_operands(ASMOperand *operands, int nb_operands,
 868                                int nb_outputs,
 869                                CString *out_str, CString *in_str)
 870 {
 871     int c, index, modifier;
 872     const char *str;
 873     ASMOperand *op;
 874     SValue sv;
 875
 876     cstr_new(out_str);
 877     str = in_str->data;
 878     for(;;) {
 879         c = *str++;
 880         if (c == '%') {
 881             if (*str == '%') {
 882                 str++;
 883                 goto add_char;
 884             }
 885             modifier = 0;
 886             if (*str == 'c' || *str == 'n' ||
 887                 *str == 'b' || *str == 'w' || *str == 'h')
 888                 modifier = *str++;
 889             index = find_constraint(operands, nb_operands, str, &str);
 890             if (index < 0)
 891                 tcc_error("invalid operand reference after %%");
 892             op = &operands[index];
 893             sv = *op->vt;
 894             if (op->reg >= 0) {
 895                 sv.r = op->reg;
 896                 if ((op->vt->r & VT_VALMASK) == VT_LLOCAL && op->is_memory)
 897                     sv.r |= VT_LVAL;
 898             }
 899             subst_asm_operand(out_str, &sv, modifier);
 900         } else {
 901         add_char:
 902             cstr_ccat(out_str, c);
 903             if (c == '\0')
 904                 break;
 905         }
 906     }
 907 }
 908
 909
 910 static void parse_asm_operands(ASMOperand *operands, int *nb_operands_ptr,
 911                                int is_output)
 912 {
 913     ASMOperand *op;
 914     int nb_operands;
 915
 916     if (tok != ':') {
 917         nb_operands = *nb_operands_ptr;
 918         for(;;) {
 919             if (nb_operands >= MAX_ASM_OPERANDS)
 920                 tcc_error("too many asm operands");
 921             op = &operands[nb_operands++];
 922             op->id = 0;
 923             if (tok == '[') {
 924                 next();
 925                 if (tok < TOK_IDENT)
 926                     expect("identifier");
 927                 op->id = tok;
 928                 next();
 929                 skip(']');
 930             }
 931             if (tok != TOK_STR)
 932                 expect("string constant");
 933             op->constraint = tcc_malloc(tokc.cstr->size);
 934             strcpy(op->constraint, tokc.cstr->data);
 935             next();
 936             skip('(');
 937             gexpr();
 938             if (is_output) {
 939                 test_lvalue();
 940             } else {
 941                 /* we want to avoid LLOCAL case, except when the 'm'
 942                    constraint is used. Note that it may come from
 943                    register storage, so we need to convert (reg)
 944                    case */
 945                 if ((vtop->r & VT_LVAL) &&
 946                     ((vtop->r & VT_VALMASK) == VT_LLOCAL ||
 947                      (vtop->r & VT_VALMASK) < VT_CONST) &&
 948                     !strchr(op->constraint, 'm')) {
 949                     gv(RC_INT);
 950                 }
 951             }
 952             op->vt = vtop;
 953             skip(')');
 954             if (tok == ',') {
 955                 next();
 956             } else {
 957                 break;
 958             }
 959         }
 960         *nb_operands_ptr = nb_operands;
 961     }
 962 }
 963
 964 /* parse the GCC asm() instruction */
 965 ST_FUNC void asm_instr(void)
 966 {
 967     CString astr, astr1;
 968     ASMOperand operands[MAX_ASM_OPERANDS];
 969     int nb_outputs, nb_operands, i, must_subst, out_reg;
 970     uint8_t clobber_regs[NB_ASM_REGS];
 971
 972     next();
 973     /* since we always generate the asm() instruction, we can ignore
 974        volatile */
 975     if (tok == TOK_VOLATILE1 || tok == TOK_VOLATILE2 || tok == TOK_VOLATILE3) {
 976         next();
 977     }
 978     parse_asm_str(&astr);
 979     nb_operands = 0;
 980     nb_outputs = 0;
 981     must_subst = 0;
 982     memset(clobber_regs, 0, sizeof(clobber_regs));
 983     if (tok == ':') {
 984         next();
 985         must_subst = 1;
 986         /* output args */
 987         parse_asm_operands(operands, &nb_operands, 1);
 988         nb_outputs = nb_operands;
 989         if (tok == ':') {
 990             next();
 991             if (tok != ')') {
 992                 /* input args */
 993                 parse_asm_operands(operands, &nb_operands, 0);
 994                 if (tok == ':') {
 995                     /* clobber list */
 996                     /* XXX: handle registers */
 997                     next();
 998                     for(;;) {
 999                         if (tok != TOK_STR)
1000                             expect("string constant");
1001                         asm_clobber(clobber_regs, tokc.cstr->data);
1002                         next();
1003                         if (tok == ',') {
1004                             next();
1005                         } else {
1006                             break;
1007                         }
1008                     }
1009                 }
1010             }
1011         }
1012     }
1013     skip(')');
1014     /* NOTE: we do not eat the ';' so that we can restore the current
1015        token after the assembler parsing */
1016     if (tok != ';')
1017         expect("';'");
1018
1019     /* save all values in the memory */
1020     save_regs(0);
1021
1022     /* compute constraints */
1023     asm_compute_constraints(operands, nb_operands, nb_outputs,
1024                             clobber_regs, &out_reg);
1025
1026     /* substitute the operands in the asm string. No substitution is
1027        done if no operands (GCC behaviour) */
1028 #ifdef ASM_DEBUG
1029     printf("asm: \"%s\"\n", (char *)astr.data);
1030 #endif
1031     if (must_subst) {
1032         subst_asm_operands(operands, nb_operands, nb_outputs, &astr1, &astr);
1033         cstr_free(&astr);
1034     } else {
1035         astr1 = astr;
1036     }
1037 #ifdef ASM_DEBUG
1038     printf("subst_asm: \"%s\"\n", (char *)astr1.data);
1039 #endif
1040
1041     /* generate loads */
1042     asm_gen_code(operands, nb_operands, nb_outputs, 0,
1043                  clobber_regs, out_reg);
1044
1045     /* assemble the string with tcc internal assembler */
1046     tcc_assemble_inline(tcc_state, astr1.data, astr1.size - 1);
1047
1048     /* restore the current C token */
1049     next();
1050
1051     /* store the output values if needed */
1052     asm_gen_code(operands, nb_operands, nb_outputs, 1,
1053                  clobber_regs, out_reg);
1054
1055     /* free everything */
1056     for(i=0;i<nb_operands;i++) {
1057         ASMOperand *op;
1058         op = &operands[i];
1059         tcc_free(op->constraint);
1060         vpop();
1061     }
1062     cstr_free(&astr1);
1063 }
1064
1065 ST_FUNC void asm_global_instr(void)
1066 {
1067     CString astr;
1068
1069     next();
1070     parse_asm_str(&astr);
1071     skip(')');
1072     /* NOTE: we do not eat the ';' so that we can restore the current
1073        token after the assembler parsing */
1074     if (tok != ';')
1075         expect("';'");
1076
1077 #ifdef ASM_DEBUG
1078     printf("asm_global: \"%s\"\n", (char *)astr.data);
1079 #endif
1080     cur_text_section = text_section;
1081     ind = cur_text_section->data_offset;
1082
1083     /* assemble the string with tcc internal assembler */
1084     tcc_assemble_inline(tcc_state, astr.data, astr.size - 1);
1085
1086     cur_text_section->data_offset = ind;
1087
1088     /* restore the current C token */
1089     next();
1090
1091     cstr_free(&astr);
1092 }
1093 #endif /* CONFIG_TCC_ASM */