libobjc/encoding.c

   1 /* Encoding of types for Objective C.
   2    Copyright (C) 1993-2024 Free Software Foundation, Inc.
   3    Contributed by Kresten Krab Thorup
   4    Bitfield support by Ovidiu Predescu
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify
   9 it under the terms of the GNU General Public License as published by
  10 the Free Software Foundation; either version 3, or (at your option)
  11 any later version.
  12
  13 GCC is distributed in the hope that it will be useful,
  14 but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 GNU General Public License for more details.
  17
  18 Under Section 7 of GPL version 3, you are granted additional
  19 permissions described in the GCC Runtime Library Exception, version
  20 3.1, as published by the Free Software Foundation.
  21
  22 You should have received a copy of the GNU General Public License and
  23 a copy of the GCC Runtime Library Exception along with this program;
  24 see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  25 <http://www.gnu.org/licenses/>.  */
  26
  27 /* FIXME: This file has no business including tm.h.  */
  28
  29 /* FIXME: This file contains functions that will abort the entire
  30    program if they fail.  Is that really needed ?  */
  31
  32 #include "config.h"
  33 #include "objc-private/common.h"
  34 #include "objc-private/error.h"
  35 #include "tconfig.h"
  36 #include "coretypes.h"
  37 #include "tm.h"
  38 #include "objc/runtime.h"
  39 #include "objc-private/module-abi-8.h" /* For struct objc_method */
  40 #include <stdlib.h>
  41 #include <ctype.h>
  42 #include <string.h>                    /* For memcpy.  */
  43
  44 #undef  MAX
  45 #define MAX(X, Y)                    \
  46   ({ typeof (X) __x = (X), __y = (Y); \
  47      (__x > __y ? __x : __y); })
  48
  49 #undef  MIN
  50 #define MIN(X, Y)                    \
  51   ({ typeof (X) __x = (X), __y = (Y); \
  52      (__x < __y ? __x : __y); })
  53
  54 #undef  ROUND
  55 #define ROUND(V, A) \
  56   ({ typeof (V) __v = (V); typeof (A) __a = (A); \
  57      __a * ((__v+__a - 1)/__a); })
  58
  59
  60 /* Various hacks for objc_layout_record. These are used by the target
  61    macros. */
  62
  63 #define TREE_CODE(TYPE) *(TYPE)
  64 #define TREE_TYPE(TREE) (TREE)
  65
  66 #define RECORD_TYPE     _C_STRUCT_B
  67 #define UNION_TYPE      _C_UNION_B
  68 #define QUAL_UNION_TYPE _C_UNION_B
  69 #define ARRAY_TYPE      _C_ARY_B
  70 #define RECORD_OR_UNION_TYPE_P(TYPE)                    \
  71         ((TREE_CODE (TYPE) == RECORD_TYPE)              \
  72          || (TREE_CODE (TYPE) == UNION_TYPE)            \
  73          || (TREE_CODE (TYPE) == QUAL_UNION_TYPE))
  74 #define VECTOR_TYPE_P(TYPE) (TREE_CODE (TYPE) == VECTOR_TYPE)
  75
  76 #define REAL_TYPE       _C_DBL
  77
  78 #define VECTOR_TYPE     _C_VECTOR
  79
  80 #define TYPE_FIELDS(TYPE)           ({const char *_field = (TYPE)+1; \
  81     while (*_field != _C_STRUCT_E && *_field != _C_STRUCT_B \
  82            && *_field != _C_UNION_B && *_field++ != '=') \
  83     /* do nothing */; \
  84     _field;})
  85
  86 #define DECL_MODE(TYPE) *(TYPE)
  87 #define TYPE_MODE(TYPE) *(TYPE)
  88
  89 #undef  DFmode
  90 #define DFmode          _C_DBL
  91
  92 #define strip_array_types(TYPE)      ({const char *_field = (TYPE); \
  93   while (*_field == _C_ARY_B)\
  94     {\
  95       while (isdigit ((unsigned char)*++_field))\
  96         ;\
  97     }\
  98     _field;})
  99
 100 /* Some ports (eg ARM) allow the structure size boundary to be
 101    selected at compile-time.  We override the normal definition with
 102    one that has a constant value for this compilation.  */
 103 #undef  STRUCTURE_SIZE_BOUNDARY
 104 #define STRUCTURE_SIZE_BOUNDARY (__CHAR_BIT__ * sizeof (struct{char a;}))
 105
 106 /* Some ROUND_TYPE_ALIGN macros use TARGET_foo, and consequently
 107    target_flags.  Define a dummy entry here to so we don't die.
 108    We have to rename it because target_flags may already have been
 109    declared extern.  */
 110 #define target_flags not_target_flags
 111 static int __attribute__ ((__unused__)) not_target_flags = 0;
 112
 113 /* Some ROUND_TYPE_ALIGN use ALTIVEC_VECTOR_MODE (rs6000 darwin).
 114    Define a dummy ALTIVEC_VECTOR_MODE so it will not die.  */
 115 #undef ALTIVEC_VECTOR_MODE
 116 #define ALTIVEC_VECTOR_MODE(MODE) (0)
 117
 118 /* Replace TARGET_VSX, TARGET_ALTIVEC, and TARGET_64BIT with constants based on
 119    the current switches, rather than looking in the options structure.  */
 120 #ifdef _ARCH_PPC
 121 #undef TARGET_VSX
 122 #undef TARGET_ALTIVEC
 123 #undef TARGET_64BIT
 124
 125 #ifdef __VSX__
 126 #define TARGET_VSX 1
 127 #else
 128 #define TARGET_VSX 0
 129 #endif
 130
 131 #ifdef __ALTIVEC__
 132 #define TARGET_ALTIVEC 1
 133 #else
 134 #define TARGET_ALTIVEC 0
 135 #endif
 136
 137 #ifdef _ARCH_PPC64
 138 #define TARGET_64BIT 1
 139 #else
 140 #define TARGET_64BIT 0
 141 #endif
 142 #endif
 143
 144 /* Furthermore, some (powerpc) targets also use TARGET_ALIGN_NATURAL
 145  in their alignment macros. Currently[4.5/6], rs6000.h points this
 146  to a static variable, initialized by target overrides. This is reset
 147  in linux64.h but not in darwin64.h.  The macro is not used by *86*.  */
 148
 149 #if __MACH__
 150 # if __LP64__
 151 #  undef TARGET_ALIGN_NATURAL
 152 #  define TARGET_ALIGN_NATURAL 1
 153 # endif
 154 /* On Darwin32, we need to recurse until we find the starting stuct type.  */
 155 static int
 156 _darwin_rs6000_special_round_type_align (const char *struc, int comp, int spec)
 157 {
 158   const char *_stp , *_fields = TYPE_FIELDS (struc);
 159   if (!_fields)
 160     return MAX (comp, spec);
 161   _stp = strip_array_types (_fields);
 162   if (TYPE_MODE(_stp) == _C_COMPLEX)
 163    _stp++;
 164   switch (TYPE_MODE(_stp))
 165     {
 166       case RECORD_TYPE:
 167       case UNION_TYPE:
 168         return MAX (MAX (comp, spec), objc_alignof_type (_stp) * __CHAR_BIT__);
 169         break;
 170       case DFmode:
 171       case _C_LNG_LNG:
 172       case _C_ULNG_LNG:
 173         return MAX (MAX (comp, spec), 64);
 174         break;
 175
 176       default:
 177         return MAX (comp, spec);
 178         break;
 179     }
 180 }
 181
 182 /* See comment below.  */
 183 #define darwin_rs6000_special_round_type_align(S,C,S2)                  \
 184   (_darwin_rs6000_special_round_type_align ((char*)(S), (int)(C), (int)(S2)))
 185 #endif
 186
 187 /*  FIXME: while this file has no business including tm.h, this
 188     definitely has no business defining this macro but it
 189     is only way around without really rewritting this file,
 190     should look after the branch of 3.4 to fix this.   */
 191 #define rs6000_special_round_type_align(STRUCT, COMPUTED, SPECIFIED)    \
 192   ({ const char *_fields = TYPE_FIELDS (STRUCT);                        \
 193   ((_fields != 0                                                        \
 194     && TYPE_MODE (strip_array_types (TREE_TYPE (_fields))) == DFmode)   \
 195    ? MAX (MAX (COMPUTED, SPECIFIED), 64)                                \
 196    : MAX (COMPUTED, SPECIFIED));})
 197
 198 #define rs6000_special_adjust_field_align_p(FIELD, COMPUTED) 0
 199
 200 /* Skip a variable name, enclosed in quotes (").  */
 201 static inline
 202 const char *
 203 objc_skip_variable_name (const char *type)
 204 {
 205   /* Skip the variable name if any.  */
 206   if (*type == '"')
 207     {
 208       /* FIXME: How do we know we won't read beyond the end of the
 209          string.  Here and in the rest of the file!  */
 210       /* Skip '"'.  */
 211       type++;
 212       /* Skip to the next '"'.  */
 213       while (*type != '"')
 214         type++;
 215       /* Skip '"'.  */
 216       type++;
 217     }
 218
 219   return type;
 220 }
 221
 222 int
 223 objc_sizeof_type (const char *type)
 224 {
 225   type = objc_skip_variable_name (type);
 226
 227   switch (*type) {
 228   case _C_BOOL:
 229     return sizeof (_Bool);
 230     break;
 231
 232   case _C_ID:
 233     return sizeof (id);
 234     break;
 235
 236   case _C_CLASS:
 237     return sizeof (Class);
 238     break;
 239
 240   case _C_SEL:
 241     return sizeof (SEL);
 242     break;
 243
 244   case _C_CHR:
 245     return sizeof (char);
 246     break;
 247
 248   case _C_UCHR:
 249     return sizeof (unsigned char);
 250     break;
 251
 252   case _C_SHT:
 253     return sizeof (short);
 254     break;
 255
 256   case _C_USHT:
 257     return sizeof (unsigned short);
 258     break;
 259
 260   case _C_INT:
 261     return sizeof (int);
 262     break;
 263
 264   case _C_UINT:
 265     return sizeof (unsigned int);
 266     break;
 267
 268   case _C_LNG:
 269     return sizeof (long);
 270     break;
 271
 272   case _C_ULNG:
 273     return sizeof (unsigned long);
 274     break;
 275
 276   case _C_LNG_LNG:
 277     return sizeof (long long);
 278     break;
 279
 280   case _C_ULNG_LNG:
 281     return sizeof (unsigned long long);
 282     break;
 283
 284   case _C_FLT:
 285     return sizeof (float);
 286     break;
 287
 288   case _C_DBL:
 289     return sizeof (double);
 290     break;
 291
 292   case _C_LNG_DBL:
 293     return sizeof (long double);
 294     break;
 295
 296   case _C_VOID:
 297     return sizeof (void);
 298     break;
 299
 300   case _C_PTR:
 301   case _C_ATOM:
 302   case _C_CHARPTR:
 303     return sizeof (char *);
 304     break;
 305
 306   case _C_ARY_B:
 307     {
 308       int len = atoi (type + 1);
 309       while (isdigit ((unsigned char)*++type))
 310         ;
 311       return len * objc_aligned_size (type);
 312     }
 313     break;
 314
 315   case _C_VECTOR:
 316     {
 317       /* Skip the '!'.  */
 318       type++;
 319       /* Skip the '['.  */
 320       type++;
 321
 322       /* The size in bytes is the following number.  */
 323       int size = atoi (type);
 324       return size;
 325     }
 326     break;
 327
 328   case _C_BFLD:
 329     {
 330       /* The GNU encoding of bitfields is: b 'position' 'type'
 331          'size'.  */
 332       int position, size;
 333       int startByte, endByte;
 334
 335       position = atoi (type + 1);
 336       while (isdigit ((unsigned char)*++type))
 337         ;
 338       size = atoi (type + 1);
 339
 340       startByte = position / __CHAR_BIT__;
 341       endByte = (position + size) / __CHAR_BIT__;
 342       return endByte - startByte;
 343     }
 344
 345   case _C_UNION_B:
 346   case _C_STRUCT_B:
 347     {
 348       struct objc_struct_layout layout;
 349       unsigned int size;
 350
 351       objc_layout_structure (type, &layout);
 352       while (objc_layout_structure_next_member (&layout))
 353         /* do nothing */ ;
 354       objc_layout_finish_structure (&layout, &size, NULL);
 355
 356       return size;
 357     }
 358
 359   case _C_COMPLEX:
 360     {
 361       type++; /* Skip after the 'j'. */
 362       switch (*type)
 363         {
 364             case _C_CHR:
 365               return sizeof (_Complex char);
 366               break;
 367
 368             case _C_UCHR:
 369               return sizeof (_Complex unsigned char);
 370               break;
 371
 372             case _C_SHT:
 373               return sizeof (_Complex short);
 374               break;
 375
 376             case _C_USHT:
 377               return sizeof (_Complex unsigned short);
 378               break;
 379
 380             case _C_INT:
 381               return sizeof (_Complex int);
 382               break;
 383
 384             case _C_UINT:
 385               return sizeof (_Complex unsigned int);
 386               break;
 387
 388             case _C_LNG:
 389               return sizeof (_Complex long);
 390               break;
 391
 392             case _C_ULNG:
 393               return sizeof (_Complex unsigned long);
 394               break;
 395
 396             case _C_LNG_LNG:
 397               return sizeof (_Complex long long);
 398               break;
 399
 400             case _C_ULNG_LNG:
 401               return sizeof (_Complex unsigned long long);
 402               break;
 403
 404             case _C_FLT:
 405               return sizeof (_Complex float);
 406               break;
 407
 408             case _C_DBL:
 409               return sizeof (_Complex double);
 410               break;
 411
 412             case _C_LNG_DBL:
 413               return sizeof (_Complex long double);
 414               break;
 415
 416             default:
 417               {
 418                 /* FIXME: Is this so bad that we have to abort the
 419                    entire program ?  (it applies to all the other
 420                    _objc_abort calls in this file).
 421                 */
 422                 _objc_abort ("unknown complex type %s\n", type);
 423                 return 0;
 424               }
 425         }
 426     }
 427
 428   default:
 429     {
 430       _objc_abort ("unknown type %s\n", type);
 431       return 0;
 432     }
 433   }
 434 }
 435
 436 int
 437 objc_alignof_type (const char *type)
 438 {
 439   type = objc_skip_variable_name (type);
 440
 441   switch (*type) {
 442   case _C_BOOL:
 443     return __alignof__ (_Bool);
 444     break;
 445
 446   case _C_ID:
 447     return __alignof__ (id);
 448     break;
 449
 450   case _C_CLASS:
 451     return __alignof__ (Class);
 452     break;
 453
 454   case _C_SEL:
 455     return __alignof__ (SEL);
 456     break;
 457
 458   case _C_CHR:
 459     return __alignof__ (char);
 460     break;
 461
 462   case _C_UCHR:
 463     return __alignof__ (unsigned char);
 464     break;
 465
 466   case _C_SHT:
 467     return __alignof__ (short);
 468     break;
 469
 470   case _C_USHT:
 471     return __alignof__ (unsigned short);
 472     break;
 473
 474   case _C_INT:
 475     return __alignof__ (int);
 476     break;
 477
 478   case _C_UINT:
 479     return __alignof__ (unsigned int);
 480     break;
 481
 482   case _C_LNG:
 483     return __alignof__ (long);
 484     break;
 485
 486   case _C_ULNG:
 487     return __alignof__ (unsigned long);
 488     break;
 489
 490   case _C_LNG_LNG:
 491     return __alignof__ (long long);
 492     break;
 493
 494   case _C_ULNG_LNG:
 495     return __alignof__ (unsigned long long);
 496     break;
 497
 498   case _C_FLT:
 499     return __alignof__ (float);
 500     break;
 501
 502   case _C_DBL:
 503     return __alignof__ (double);
 504     break;
 505
 506   case _C_LNG_DBL:
 507     return __alignof__ (long double);
 508     break;
 509
 510   case _C_PTR:
 511   case _C_ATOM:
 512   case _C_CHARPTR:
 513     return __alignof__ (char *);
 514     break;
 515
 516   case _C_ARY_B:
 517     while (isdigit ((unsigned char)*++type))
 518       /* do nothing */;
 519     return objc_alignof_type (type);
 520
 521   case _C_VECTOR:
 522     {
 523       /* Skip the '!'.  */
 524       type++;
 525       /* Skip the '['.  */
 526       type++;
 527
 528       /* Skip the size.  */
 529       while (isdigit ((unsigned char)*type))
 530         type++;
 531
 532       /* Skip the ','.  */
 533       type++;
 534
 535       /* The alignment in bytes is the following number.  */
 536       return atoi (type);
 537     }
 538   case _C_STRUCT_B:
 539   case _C_UNION_B:
 540     {
 541       struct objc_struct_layout layout;
 542       unsigned int align;
 543
 544       objc_layout_structure (type, &layout);
 545       while (objc_layout_structure_next_member (&layout))
 546         /* do nothing */;
 547       objc_layout_finish_structure (&layout, NULL, &align);
 548
 549       return align;
 550     }
 551
 552
 553   case _C_COMPLEX:
 554     {
 555       type++; /* Skip after the 'j'. */
 556       switch (*type)
 557         {
 558             case _C_CHR:
 559               return __alignof__ (_Complex char);
 560               break;
 561
 562             case _C_UCHR:
 563               return __alignof__ (_Complex unsigned char);
 564               break;
 565
 566             case _C_SHT:
 567               return __alignof__ (_Complex short);
 568               break;
 569
 570             case _C_USHT:
 571               return __alignof__ (_Complex unsigned short);
 572               break;
 573
 574             case _C_INT:
 575               return __alignof__ (_Complex int);
 576               break;
 577
 578             case _C_UINT:
 579               return __alignof__ (_Complex unsigned int);
 580               break;
 581
 582             case _C_LNG:
 583               return __alignof__ (_Complex long);
 584               break;
 585
 586             case _C_ULNG:
 587               return __alignof__ (_Complex unsigned long);
 588               break;
 589
 590             case _C_LNG_LNG:
 591               return __alignof__ (_Complex long long);
 592               break;
 593
 594             case _C_ULNG_LNG:
 595               return __alignof__ (_Complex unsigned long long);
 596               break;
 597
 598             case _C_FLT:
 599               return __alignof__ (_Complex float);
 600               break;
 601
 602             case _C_DBL:
 603               return __alignof__ (_Complex double);
 604               break;
 605
 606             case _C_LNG_DBL:
 607               return __alignof__ (_Complex long double);
 608               break;
 609
 610             default:
 611               {
 612                 _objc_abort ("unknown complex type %s\n", type);
 613                 return 0;
 614               }
 615         }
 616     }
 617
 618   default:
 619     {
 620       _objc_abort ("unknown type %s\n", type);
 621       return 0;
 622     }
 623   }
 624 }
 625
 626 int
 627 objc_aligned_size (const char *type)
 628 {
 629   int size, align;
 630
 631   type = objc_skip_variable_name (type);
 632   size = objc_sizeof_type (type);
 633   align = objc_alignof_type (type);
 634
 635   return ROUND (size, align);
 636 }
 637
 638 int
 639 objc_promoted_size (const char *type)
 640 {
 641   int size, wordsize;
 642
 643   type = objc_skip_variable_name (type);
 644   size = objc_sizeof_type (type);
 645   wordsize = sizeof (void *);
 646
 647   return ROUND (size, wordsize);
 648 }
 649
 650 inline
 651 const char *
 652 objc_skip_type_qualifiers (const char *type)
 653 {
 654   while (*type == _C_CONST
 655          || *type == _C_IN
 656          || *type == _C_INOUT
 657          || *type == _C_OUT
 658          || *type == _C_BYCOPY
 659          || *type == _C_BYREF
 660          || *type == _C_ONEWAY
 661          || *type == _C_GCINVISIBLE)
 662     {
 663       type += 1;
 664     }
 665   return type;
 666 }
 667
 668 inline
 669 const char *
 670 objc_skip_typespec (const char *type)
 671 {
 672   type = objc_skip_variable_name (type);
 673   type = objc_skip_type_qualifiers (type);
 674
 675   switch (*type) {
 676
 677   case _C_ID:
 678     /* An id may be annotated by the actual type if it is known
 679        with the @"ClassName" syntax */
 680
 681     if (*++type != '"')
 682       return type;
 683     else
 684       {
 685         while (*++type != '"')
 686           /* do nothing */;
 687         return type + 1;
 688       }
 689
 690     /* The following are one character type codes */
 691   case _C_CLASS:
 692   case _C_SEL:
 693   case _C_CHR:
 694   case _C_UCHR:
 695   case _C_CHARPTR:
 696   case _C_ATOM:
 697   case _C_SHT:
 698   case _C_USHT:
 699   case _C_INT:
 700   case _C_UINT:
 701   case _C_LNG:
 702   case _C_BOOL:
 703   case _C_ULNG:
 704   case _C_LNG_LNG:
 705   case _C_ULNG_LNG:
 706   case _C_FLT:
 707   case _C_DBL:
 708   case _C_LNG_DBL:
 709   case _C_VOID:
 710   case _C_UNDEF:
 711     return ++type;
 712     break;
 713
 714   case _C_COMPLEX:
 715     return type + 2;
 716     break;
 717
 718   case _C_ARY_B:
 719     /* skip digits, typespec and closing ']' */
 720     while (isdigit ((unsigned char)*++type))
 721       ;
 722     type = objc_skip_typespec (type);
 723     if (*type == _C_ARY_E)
 724       return ++type;
 725     else
 726       {
 727         _objc_abort ("bad array type %s\n", type);
 728         return 0;
 729       }
 730
 731   case _C_VECTOR:
 732     /* Skip '!' */
 733     type++;
 734     /* Skip '[' */
 735     type++;
 736     /* Skip digits (size) */
 737     while (isdigit ((unsigned char)*type))
 738       type++;
 739     /* Skip ',' */
 740     type++;
 741     /* Skip digits (alignment) */
 742     while (isdigit ((unsigned char)*type))
 743       type++;
 744     /* Skip typespec.  */
 745     type = objc_skip_typespec (type);
 746     /* Skip closing ']'.  */
 747     if (*type == _C_ARY_E)
 748       return ++type;
 749     else
 750       {
 751         _objc_abort ("bad vector type %s\n", type);
 752         return 0;
 753       }
 754
 755   case _C_BFLD:
 756     /* The GNU encoding of bitfields is: b 'position' 'type'
 757        'size'.  */
 758     while (isdigit ((unsigned char)*++type))
 759       ; /* skip position */
 760     while (isdigit ((unsigned char)*++type))
 761       ; /* skip type and size */
 762     return type;
 763
 764   case _C_STRUCT_B:
 765     /* skip name, and elements until closing '}'  */
 766
 767     while (*type != _C_STRUCT_E && *type++ != '=')
 768       ;
 769     while (*type != _C_STRUCT_E)
 770       {
 771         type = objc_skip_typespec (type);
 772       }
 773     return ++type;
 774
 775   case _C_UNION_B:
 776     /* skip name, and elements until closing ')'  */
 777
 778     while (*type != _C_UNION_E && *type++ != '=')
 779       ;
 780     while (*type != _C_UNION_E)
 781       {
 782         type = objc_skip_typespec (type);
 783       }
 784     return ++type;
 785
 786   case _C_PTR:
 787     /* Just skip the following typespec */
 788
 789     return objc_skip_typespec (++type);
 790
 791   default:
 792     {
 793       _objc_abort ("unknown type %s\n", type);
 794       return 0;
 795     }
 796   }
 797 }
 798
 799 inline
 800 const char *
 801 objc_skip_offset (const char *type)
 802 {
 803   /* The offset is prepended by a '+' if the argument is passed in
 804      registers.  PS: The compiler stopped generating this '+' in
 805      version 3.4.  */
 806   if (*type == '+')
 807     type++;
 808
 809   /* Some people claim that on some platforms, where the stack grows
 810      backwards, the compiler generates negative offsets (??).  Skip a
 811      '-' for such a negative offset.  */
 812   if (*type == '-')
 813     type++;
 814
 815   /* Skip the digits that represent the offset.  */
 816   while (isdigit ((unsigned char) *type))
 817     type++;
 818
 819   return type;
 820 }
 821
 822 const char *
 823 objc_skip_argspec (const char *type)
 824 {
 825   type = objc_skip_typespec (type);
 826   type = objc_skip_offset (type);
 827   return type;
 828 }
 829
 830 char *
 831 method_copyReturnType (struct objc_method *method)
 832 {
 833   if (method == NULL)
 834     return 0;
 835   else
 836     {
 837       char *returnValue;
 838       size_t returnValueSize;
 839
 840       /* Determine returnValueSize.  */
 841       {
 842         /* Find the end of the first argument.  We want to return the
 843            first argument spec, plus 1 byte for the \0 at the end.  */
 844         const char *type = method->method_types;
 845         if (*type == '\0')
 846           return NULL;
 847         type = objc_skip_argspec (type);
 848         returnValueSize = type - method->method_types + 1;
 849       }
 850
 851       /* Copy the first argument into returnValue.  */
 852       returnValue = malloc (sizeof (char) * returnValueSize);
 853       memcpy (returnValue, method->method_types, returnValueSize);
 854       returnValue[returnValueSize - 1] = '\0';
 855
 856       return returnValue;
 857     }
 858 }
 859
 860 char *
 861 method_copyArgumentType (struct objc_method * method, unsigned int argumentNumber)
 862 {
 863   if (method == NULL)
 864     return 0;
 865   else
 866     {
 867       char *returnValue;
 868       const char *returnValueStart;
 869       size_t returnValueSize;
 870
 871       /* Determine returnValueStart and returnValueSize.  */
 872       {
 873         const char *type = method->method_types;
 874
 875         /* Skip the first argument (return type).  */
 876         type = objc_skip_argspec (type);
 877
 878         /* Now keep skipping arguments until we get to
 879            argumentNumber.  */
 880         while (argumentNumber > 0)
 881           {
 882             /* We are supposed to skip an argument, but the string is
 883                finished.  This means we were asked for a non-existing
 884                argument.  */
 885             if (*type == '\0')
 886               return NULL;
 887
 888             type = objc_skip_argspec (type);
 889             argumentNumber--;
 890           }
 891
 892         /* If the argument does not exist, return NULL.  */
 893         if (*type == '\0')
 894           return NULL;
 895
 896         returnValueStart = type;
 897         type = objc_skip_argspec (type);
 898         returnValueSize = type - returnValueStart + 1;
 899       }
 900
 901       /* Copy the argument into returnValue.  */
 902       returnValue = malloc (sizeof (char) * returnValueSize);
 903       memcpy (returnValue, returnValueStart, returnValueSize);
 904       returnValue[returnValueSize - 1] = '\0';
 905
 906       return returnValue;
 907     }
 908 }
 909
 910 void method_getReturnType (struct objc_method * method, char *returnValue,
 911                            size_t returnValueSize)
 912 {
 913   if (returnValue == NULL  ||  returnValueSize == 0)
 914     return;
 915
 916   /* Zero the string; we'll then write the argument type at the
 917      beginning of it, if needed.  */
 918   memset (returnValue, 0, returnValueSize);
 919
 920   if (method == NULL)
 921     return;
 922   else
 923     {
 924       size_t argumentTypeSize;
 925
 926       /* Determine argumentTypeSize.  */
 927       {
 928         /* Find the end of the first argument.  We want to return the
 929            first argument spec.  */
 930         const char *type = method->method_types;
 931         if (*type == '\0')
 932           return;
 933         type = objc_skip_argspec (type);
 934         argumentTypeSize = type - method->method_types;
 935         if (argumentTypeSize > returnValueSize)
 936           argumentTypeSize = returnValueSize;
 937       }
 938       /* Copy the argument at the beginning of the string.  */
 939       memcpy (returnValue, method->method_types, argumentTypeSize);
 940     }
 941 }
 942
 943 void method_getArgumentType (struct objc_method * method, unsigned int argumentNumber,
 944                              char *returnValue, size_t returnValueSize)
 945 {
 946   if (returnValue == NULL  ||  returnValueSize == 0)
 947     return;
 948
 949   /* Zero the string; we'll then write the argument type at the
 950      beginning of it, if needed.  */
 951   memset (returnValue, 0, returnValueSize);
 952
 953   if (method == NULL)
 954     return;
 955   else
 956     {
 957       const char *returnValueStart;
 958       size_t argumentTypeSize;
 959
 960       /* Determine returnValueStart and argumentTypeSize.  */
 961       {
 962         const char *type = method->method_types;
 963
 964         /* Skip the first argument (return type).  */
 965         type = objc_skip_argspec (type);
 966
 967         /* Now keep skipping arguments until we get to
 968            argumentNumber.  */
 969         while (argumentNumber > 0)
 970           {
 971             /* We are supposed to skip an argument, but the string is
 972                finished.  This means we were asked for a non-existing
 973                argument.  */
 974             if (*type == '\0')
 975               return;
 976
 977             type = objc_skip_argspec (type);
 978             argumentNumber--;
 979           }
 980
 981         /* If the argument does not exist, it's game over.  */
 982         if (*type == '\0')
 983           return;
 984
 985         returnValueStart = type;
 986         type = objc_skip_argspec (type);
 987         argumentTypeSize = type - returnValueStart;
 988         if (argumentTypeSize > returnValueSize)
 989           argumentTypeSize = returnValueSize;
 990       }
 991       /* Copy the argument at the beginning of the string.  */
 992       memcpy (returnValue, returnValueStart, argumentTypeSize);
 993     }
 994 }
 995
 996 unsigned int
 997 method_getNumberOfArguments (struct objc_method *method)
 998 {
 999   if (method == NULL)
1000     return 0;
1001   else
1002     {
1003       unsigned int i = 0;
1004       const char *type = method->method_types;
1005       while (*type)
1006         {
1007           type = objc_skip_argspec (type);
1008           i += 1;
1009         }
1010
1011       if (i == 0)
1012         {
1013           /* This could only happen if method_types is invalid; in
1014              that case, return 0.  */
1015           return 0;
1016         }
1017       else
1018         {
1019           /* Remove the return type.  */
1020           return (i - 1);
1021         }
1022     }
1023 }
1024
1025 unsigned
1026 objc_get_type_qualifiers (const char *type)
1027 {
1028   unsigned res = 0;
1029   BOOL flag = YES;
1030
1031   while (flag)
1032     switch (*type++)
1033       {
1034       case _C_CONST:       res |= _F_CONST; break;
1035       case _C_IN:          res |= _F_IN; break;
1036       case _C_INOUT:       res |= _F_INOUT; break;
1037       case _C_OUT:         res |= _F_OUT; break;
1038       case _C_BYCOPY:      res |= _F_BYCOPY; break;
1039       case _C_BYREF:       res |= _F_BYREF; break;
1040       case _C_ONEWAY:      res |= _F_ONEWAY; break;
1041       case _C_GCINVISIBLE: res |= _F_GCINVISIBLE; break;
1042       default: flag = NO;
1043     }
1044
1045   return res;
1046 }
1047
1048 /* The following three functions can be used to determine how a
1049    structure is laid out by the compiler. For example:
1050
1051   struct objc_struct_layout layout;
1052   int i;
1053
1054   objc_layout_structure (type, &layout);
1055   while (objc_layout_structure_next_member (&layout))
1056     {
1057       int position, align;
1058       const char *type;
1059
1060       objc_layout_structure_get_info (&layout, &position, &align, &type);
1061       printf ("element %d has offset %d, alignment %d\n",
1062               i++, position, align);
1063     }
1064
1065   These functions are used by objc_sizeof_type and objc_alignof_type
1066   functions to compute the size and alignment of structures. The
1067   previous method of computing the size and alignment of a structure
1068   was not working on some architectures, particularly on AIX, and in
1069   the presence of bitfields inside the structure.  */
1070 void
1071 objc_layout_structure (const char *type,
1072                        struct objc_struct_layout *layout)
1073 {
1074   const char *ntype;
1075
1076   if (*type != _C_UNION_B && *type != _C_STRUCT_B)
1077     {
1078       _objc_abort ("record (or union) type expected in objc_layout_structure, got %s\n",
1079                    type);
1080     }
1081
1082   type ++;
1083   layout->original_type = type;
1084
1085   /* Skip "<name>=" if any. Avoid embedded structures and unions. */
1086   ntype = type;
1087   while (*ntype != _C_STRUCT_E && *ntype != _C_STRUCT_B && *ntype != _C_UNION_B
1088          && *ntype++ != '=')
1089     /* do nothing */;
1090
1091   /* If there's a "<name>=", ntype - 1 points to '='; skip the name.  */
1092   if (*(ntype - 1) == '=')
1093     type = ntype;
1094
1095   layout->type = type;
1096   layout->prev_type = NULL;
1097   layout->record_size = 0;
1098   layout->record_align = __CHAR_BIT__;
1099
1100   layout->record_align = MAX (layout->record_align, STRUCTURE_SIZE_BOUNDARY);
1101 }
1102
1103 BOOL
1104 objc_layout_structure_next_member (struct objc_struct_layout *layout)
1105 {
1106   register int desired_align = 0;
1107
1108   /* The following are used only if the field is a bitfield */
1109   register const char *bfld_type = 0;
1110   register int bfld_type_align = 0, bfld_field_size = 0;
1111
1112   /* The current type without the type qualifiers */
1113   const char *type;
1114   BOOL unionp = layout->original_type[-1] == _C_UNION_B;
1115
1116   /* Add the size of the previous field to the size of the record.  */
1117   if (layout->prev_type)
1118     {
1119       type = objc_skip_type_qualifiers (layout->prev_type);
1120       if (unionp)
1121         layout->record_size = MAX (layout->record_size,
1122                                    objc_sizeof_type (type) * __CHAR_BIT__);
1123
1124       else if (*type != _C_BFLD)
1125         layout->record_size += objc_sizeof_type (type) * __CHAR_BIT__;
1126       else {
1127         /* Get the bitfield's type */
1128         for (bfld_type = type + 1;
1129              isdigit ((unsigned char)*bfld_type);
1130              bfld_type++)
1131           /* do nothing */;
1132
1133         bfld_type_align = objc_alignof_type (bfld_type) * __CHAR_BIT__;
1134         bfld_field_size = atoi (objc_skip_typespec (bfld_type));
1135         layout->record_size += bfld_field_size;
1136       }
1137     }
1138
1139   if ((unionp && *layout->type == _C_UNION_E)
1140       || (!unionp && *layout->type == _C_STRUCT_E))
1141     return NO;
1142
1143   /* Skip the variable name if any */
1144   layout->type = objc_skip_variable_name (layout->type);
1145   type = objc_skip_type_qualifiers (layout->type);
1146
1147   if (*type != _C_BFLD)
1148     desired_align = objc_alignof_type (type) * __CHAR_BIT__;
1149   else
1150     {
1151       desired_align = 1;
1152       /* Skip the bitfield's offset */
1153       for (bfld_type = type + 1;
1154            isdigit ((unsigned char) *bfld_type);
1155            bfld_type++)
1156         /* do nothing */;
1157
1158       bfld_type_align = objc_alignof_type (bfld_type) * __CHAR_BIT__;
1159       bfld_field_size = atoi (objc_skip_typespec (bfld_type));
1160     }
1161
1162   /* The following won't work for vectors.  */
1163 #ifdef BIGGEST_FIELD_ALIGNMENT
1164   desired_align = MIN (desired_align, BIGGEST_FIELD_ALIGNMENT);
1165 #endif
1166 #ifdef ADJUST_FIELD_ALIGN
1167   desired_align = ADJUST_FIELD_ALIGN (type, type, desired_align);
1168 #endif
1169
1170   /* Record must have at least as much alignment as any field.
1171      Otherwise, the alignment of the field within the record
1172      is meaningless.  */
1173 #ifndef HAVE_BITFIELD_TYPE_MATTERS
1174   layout->record_align = MAX (layout->record_align, desired_align);
1175 #else   /* PCC_BITFIELD_TYPE_MATTERS */
1176   if (*type == _C_BFLD)
1177     {
1178       /* For these machines, a zero-length field does not
1179          affect the alignment of the structure as a whole.
1180          It does, however, affect the alignment of the next field
1181          within the structure.  */
1182       if (bfld_field_size)
1183         layout->record_align = MAX (layout->record_align, desired_align);
1184       else
1185         desired_align = objc_alignof_type (bfld_type) * __CHAR_BIT__;
1186
1187       /* A named bit field of declared type `int'
1188          forces the entire structure to have `int' alignment.
1189          Q1: How is encoded this thing and how to check for it?
1190          Q2: How to determine maximum_field_alignment at runtime? */
1191
1192 /*        if (DECL_NAME (field) != 0) */
1193       {
1194         int type_align = bfld_type_align;
1195 #if 0
1196         if (maximum_field_alignment != 0)
1197           type_align = MIN (type_align, maximum_field_alignment);
1198         else if (DECL_PACKED (field))
1199           type_align = MIN (type_align, __CHAR_BIT__);
1200 #endif
1201
1202         layout->record_align = MAX (layout->record_align, type_align);
1203       }
1204     }
1205   else
1206     layout->record_align = MAX (layout->record_align, desired_align);
1207 #endif  /* PCC_BITFIELD_TYPE_MATTERS */
1208
1209   /* Does this field automatically have alignment it needs
1210      by virtue of the fields that precede it and the record's
1211      own alignment?  */
1212
1213   if (*type == _C_BFLD)
1214     layout->record_size = atoi (type + 1);
1215   else if (layout->record_size % desired_align != 0)
1216     {
1217       /* No, we need to skip space before this field.
1218          Bump the cumulative size to multiple of field alignment.  */
1219       layout->record_size = ROUND (layout->record_size, desired_align);
1220     }
1221
1222   /* Jump to the next field in record. */
1223
1224   layout->prev_type = layout->type;
1225   layout->type = objc_skip_typespec (layout->type);      /* skip component */
1226
1227   return YES;
1228 }
1229
1230 void objc_layout_finish_structure (struct objc_struct_layout *layout,
1231                                    unsigned int *size,
1232                                    unsigned int *align)
1233 {
1234   BOOL unionp = layout->original_type[-1] == _C_UNION_B;
1235   if (layout->type
1236       && ((!unionp && *layout->type == _C_STRUCT_E)
1237           || (unionp && *layout->type == _C_UNION_E)))
1238     {
1239       /* Work out the alignment of the record as one expression and store
1240          in the record type.  Round it up to a multiple of the record's
1241          alignment. */
1242 #if defined (ROUND_TYPE_ALIGN) && ! defined (__sparc__)
1243       layout->record_align = ROUND_TYPE_ALIGN (layout->original_type-1,
1244                                                1,
1245                                                layout->record_align);
1246 #else
1247       layout->record_align = MAX (1, layout->record_align);
1248 #endif
1249
1250       /* Round the size up to be a multiple of the required alignment */
1251       layout->record_size = ROUND (layout->record_size, layout->record_align);
1252
1253       layout->type = NULL;
1254     }
1255   if (size)
1256     *size = layout->record_size / __CHAR_BIT__;
1257   if (align)
1258     *align = layout->record_align / __CHAR_BIT__;
1259 }
1260
1261 void objc_layout_structure_get_info (struct objc_struct_layout *layout,
1262                                      unsigned int *offset,
1263                                      unsigned int *align,
1264                                      const char **type)
1265 {
1266   if (offset)
1267     *offset = layout->record_size / __CHAR_BIT__;
1268   if (align)
1269     *align = layout->record_align / __CHAR_BIT__;
1270   if (type)
1271     *type = layout->prev_type;
1272 }