libobjc/encoding.c

   1 /* Encoding of types for Objective C.
   2    Copyright (C) 1993-2021 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
  71 #define REAL_TYPE       _C_DBL
  72
  73 #define VECTOR_TYPE     _C_VECTOR
  74
  75 #define TYPE_FIELDS(TYPE)           ({const char *_field = (TYPE)+1; \
  76     while (*_field != _C_STRUCT_E && *_field != _C_STRUCT_B \
  77            && *_field != _C_UNION_B && *_field++ != '=') \
  78     /* do nothing */; \
  79     _field;})
  80
  81 #define DECL_MODE(TYPE) *(TYPE)
  82 #define TYPE_MODE(TYPE) *(TYPE)
  83
  84 #undef  DFmode
  85 #define DFmode          _C_DBL
  86
  87 #define strip_array_types(TYPE)      ({const char *_field = (TYPE); \
  88   while (*_field == _C_ARY_B)\
  89     {\
  90       while (isdigit ((unsigned char)*++_field))\
  91         ;\
  92     }\
  93     _field;})
  94
  95 /* Some ports (eg ARM) allow the structure size boundary to be
  96    selected at compile-time.  We override the normal definition with
  97    one that has a constant value for this compilation.  */
  98 #undef  STRUCTURE_SIZE_BOUNDARY
  99 #define STRUCTURE_SIZE_BOUNDARY (__CHAR_BIT__ * sizeof (struct{char a;}))
 100
 101 /* Some ROUND_TYPE_ALIGN macros use TARGET_foo, and consequently
 102    target_flags.  Define a dummy entry here to so we don't die.
 103    We have to rename it because target_flags may already have been
 104    declared extern.  */
 105 #define target_flags not_target_flags
 106 static int __attribute__ ((__unused__)) not_target_flags = 0;
 107
 108 /* Some ROUND_TYPE_ALIGN use ALTIVEC_VECTOR_MODE (rs6000 darwin).
 109    Define a dummy ALTIVEC_VECTOR_MODE so it will not die.  */
 110 #undef ALTIVEC_VECTOR_MODE
 111 #define ALTIVEC_VECTOR_MODE(MODE) (0)
 112
 113 /* Replace TARGET_VSX, TARGET_ALTIVEC, and TARGET_64BIT with constants based on
 114    the current switches, rather than looking in the options structure.  */
 115 #ifdef _ARCH_PPC
 116 #undef TARGET_VSX
 117 #undef TARGET_ALTIVEC
 118 #undef TARGET_64BIT
 119
 120 #ifdef __VSX__
 121 #define TARGET_VSX 1
 122 #else
 123 #define TARGET_VSX 0
 124 #endif
 125
 126 #ifdef __ALTIVEC__
 127 #define TARGET_ALTIVEC 1
 128 #else
 129 #define TARGET_ALTIVEC 0
 130 #endif
 131
 132 #ifdef _ARCH_PPC64
 133 #define TARGET_64BIT 1
 134 #else
 135 #define TARGET_64BIT 0
 136 #endif
 137 #endif
 138
 139 /* Furthermore, some (powerpc) targets also use TARGET_ALIGN_NATURAL
 140  in their alignment macros. Currently[4.5/6], rs6000.h points this
 141  to a static variable, initialized by target overrides. This is reset
 142  in linux64.h but not in darwin64.h.  The macro is not used by *86*.  */
 143
 144 #if __MACH__
 145 # if __LP64__
 146 #  undef TARGET_ALIGN_NATURAL
 147 #  define TARGET_ALIGN_NATURAL 1
 148 # endif
 149 /* On Darwin32, we need to recurse until we find the starting stuct type.  */
 150 static int
 151 _darwin_rs6000_special_round_type_align (const char *struc, int comp, int spec)
 152 {
 153   const char *_stp , *_fields = TYPE_FIELDS (struc);
 154   if (!_fields)
 155     return MAX (comp, spec);
 156   _stp = strip_array_types (_fields);
 157   if (TYPE_MODE(_stp) == _C_COMPLEX)
 158    _stp++;
 159   switch (TYPE_MODE(_stp))
 160     {
 161       case RECORD_TYPE:
 162       case UNION_TYPE:
 163         return MAX (MAX (comp, spec), objc_alignof_type (_stp) * __CHAR_BIT__);
 164         break;
 165       case DFmode:
 166       case _C_LNG_LNG:
 167       case _C_ULNG_LNG:
 168         return MAX (MAX (comp, spec), 64);
 169         break;
 170
 171       default:
 172         return MAX (comp, spec);
 173         break;
 174     }
 175 }
 176
 177 /* See comment below.  */
 178 #define darwin_rs6000_special_round_type_align(S,C,S2)                  \
 179   (_darwin_rs6000_special_round_type_align ((char*)(S), (int)(C), (int)(S2)))
 180 #endif
 181
 182 /*  FIXME: while this file has no business including tm.h, this
 183     definitely has no business defining this macro but it
 184     is only way around without really rewritting this file,
 185     should look after the branch of 3.4 to fix this.   */
 186 #define rs6000_special_round_type_align(STRUCT, COMPUTED, SPECIFIED)    \
 187   ({ const char *_fields = TYPE_FIELDS (STRUCT);                        \
 188   ((_fields != 0                                                        \
 189     && TYPE_MODE (strip_array_types (TREE_TYPE (_fields))) == DFmode)   \
 190    ? MAX (MAX (COMPUTED, SPECIFIED), 64)                                \
 191    : MAX (COMPUTED, SPECIFIED));})
 192
 193 #define rs6000_special_adjust_field_align_p(FIELD, COMPUTED) 0
 194
 195 /* Skip a variable name, enclosed in quotes (").  */
 196 static inline
 197 const char *
 198 objc_skip_variable_name (const char *type)
 199 {
 200   /* Skip the variable name if any.  */
 201   if (*type == '"')
 202     {
 203       /* FIXME: How do we know we won't read beyond the end of the
 204          string.  Here and in the rest of the file!  */
 205       /* Skip '"'.  */
 206       type++;
 207       /* Skip to the next '"'.  */
 208       while (*type != '"')
 209         type++;
 210       /* Skip '"'.  */
 211       type++;
 212     }
 213
 214   return type;
 215 }
 216
 217 int
 218 objc_sizeof_type (const char *type)
 219 {
 220   type = objc_skip_variable_name (type);
 221
 222   switch (*type) {
 223   case _C_BOOL:
 224     return sizeof (_Bool);
 225     break;
 226
 227   case _C_ID:
 228     return sizeof (id);
 229     break;
 230
 231   case _C_CLASS:
 232     return sizeof (Class);
 233     break;
 234
 235   case _C_SEL:
 236     return sizeof (SEL);
 237     break;
 238
 239   case _C_CHR:
 240     return sizeof (char);
 241     break;
 242
 243   case _C_UCHR:
 244     return sizeof (unsigned char);
 245     break;
 246
 247   case _C_SHT:
 248     return sizeof (short);
 249     break;
 250
 251   case _C_USHT:
 252     return sizeof (unsigned short);
 253     break;
 254
 255   case _C_INT:
 256     return sizeof (int);
 257     break;
 258
 259   case _C_UINT:
 260     return sizeof (unsigned int);
 261     break;
 262
 263   case _C_LNG:
 264     return sizeof (long);
 265     break;
 266
 267   case _C_ULNG:
 268     return sizeof (unsigned long);
 269     break;
 270
 271   case _C_LNG_LNG:
 272     return sizeof (long long);
 273     break;
 274
 275   case _C_ULNG_LNG:
 276     return sizeof (unsigned long long);
 277     break;
 278
 279   case _C_FLT:
 280     return sizeof (float);
 281     break;
 282
 283   case _C_DBL:
 284     return sizeof (double);
 285     break;
 286
 287   case _C_LNG_DBL:
 288     return sizeof (long double);
 289     break;
 290
 291   case _C_VOID:
 292     return sizeof (void);
 293     break;
 294
 295   case _C_PTR:
 296   case _C_ATOM:
 297   case _C_CHARPTR:
 298     return sizeof (char *);
 299     break;
 300
 301   case _C_ARY_B:
 302     {
 303       int len = atoi (type + 1);
 304       while (isdigit ((unsigned char)*++type))
 305         ;
 306       return len * objc_aligned_size (type);
 307     }
 308     break;
 309
 310   case _C_VECTOR:
 311     {
 312       /* Skip the '!'.  */
 313       type++;
 314       /* Skip the '['.  */
 315       type++;
 316
 317       /* The size in bytes is the following number.  */
 318       int size = atoi (type);
 319       return size;
 320     }
 321     break;
 322
 323   case _C_BFLD:
 324     {
 325       /* The GNU encoding of bitfields is: b 'position' 'type'
 326          'size'.  */
 327       int position, size;
 328       int startByte, endByte;
 329
 330       position = atoi (type + 1);
 331       while (isdigit ((unsigned char)*++type))
 332         ;
 333       size = atoi (type + 1);
 334
 335       startByte = position / __CHAR_BIT__;
 336       endByte = (position + size) / __CHAR_BIT__;
 337       return endByte - startByte;
 338     }
 339
 340   case _C_UNION_B:
 341   case _C_STRUCT_B:
 342     {
 343       struct objc_struct_layout layout;
 344       unsigned int size;
 345
 346       objc_layout_structure (type, &layout);
 347       while (objc_layout_structure_next_member (&layout))
 348         /* do nothing */ ;
 349       objc_layout_finish_structure (&layout, &size, NULL);
 350
 351       return size;
 352     }
 353
 354   case _C_COMPLEX:
 355     {
 356       type++; /* Skip after the 'j'. */
 357       switch (*type)
 358         {
 359             case _C_CHR:
 360               return sizeof (_Complex char);
 361               break;
 362
 363             case _C_UCHR:
 364               return sizeof (_Complex unsigned char);
 365               break;
 366
 367             case _C_SHT:
 368               return sizeof (_Complex short);
 369               break;
 370
 371             case _C_USHT:
 372               return sizeof (_Complex unsigned short);
 373               break;
 374
 375             case _C_INT:
 376               return sizeof (_Complex int);
 377               break;
 378
 379             case _C_UINT:
 380               return sizeof (_Complex unsigned int);
 381               break;
 382
 383             case _C_LNG:
 384               return sizeof (_Complex long);
 385               break;
 386
 387             case _C_ULNG:
 388               return sizeof (_Complex unsigned long);
 389               break;
 390
 391             case _C_LNG_LNG:
 392               return sizeof (_Complex long long);
 393               break;
 394
 395             case _C_ULNG_LNG:
 396               return sizeof (_Complex unsigned long long);
 397               break;
 398
 399             case _C_FLT:
 400               return sizeof (_Complex float);
 401               break;
 402
 403             case _C_DBL:
 404               return sizeof (_Complex double);
 405               break;
 406
 407             case _C_LNG_DBL:
 408               return sizeof (_Complex long double);
 409               break;
 410
 411             default:
 412               {
 413                 /* FIXME: Is this so bad that we have to abort the
 414                    entire program ?  (it applies to all the other
 415                    _objc_abort calls in this file).
 416                 */
 417                 _objc_abort ("unknown complex type %s\n", type);
 418                 return 0;
 419               }
 420         }
 421     }
 422
 423   default:
 424     {
 425       _objc_abort ("unknown type %s\n", type);
 426       return 0;
 427     }
 428   }
 429 }
 430
 431 int
 432 objc_alignof_type (const char *type)
 433 {
 434   type = objc_skip_variable_name (type);
 435
 436   switch (*type) {
 437   case _C_BOOL:
 438     return __alignof__ (_Bool);
 439     break;
 440
 441   case _C_ID:
 442     return __alignof__ (id);
 443     break;
 444
 445   case _C_CLASS:
 446     return __alignof__ (Class);
 447     break;
 448
 449   case _C_SEL:
 450     return __alignof__ (SEL);
 451     break;
 452
 453   case _C_CHR:
 454     return __alignof__ (char);
 455     break;
 456
 457   case _C_UCHR:
 458     return __alignof__ (unsigned char);
 459     break;
 460
 461   case _C_SHT:
 462     return __alignof__ (short);
 463     break;
 464
 465   case _C_USHT:
 466     return __alignof__ (unsigned short);
 467     break;
 468
 469   case _C_INT:
 470     return __alignof__ (int);
 471     break;
 472
 473   case _C_UINT:
 474     return __alignof__ (unsigned int);
 475     break;
 476
 477   case _C_LNG:
 478     return __alignof__ (long);
 479     break;
 480
 481   case _C_ULNG:
 482     return __alignof__ (unsigned long);
 483     break;
 484
 485   case _C_LNG_LNG:
 486     return __alignof__ (long long);
 487     break;
 488
 489   case _C_ULNG_LNG:
 490     return __alignof__ (unsigned long long);
 491     break;
 492
 493   case _C_FLT:
 494     return __alignof__ (float);
 495     break;
 496
 497   case _C_DBL:
 498     return __alignof__ (double);
 499     break;
 500
 501   case _C_LNG_DBL:
 502     return __alignof__ (long double);
 503     break;
 504
 505   case _C_PTR:
 506   case _C_ATOM:
 507   case _C_CHARPTR:
 508     return __alignof__ (char *);
 509     break;
 510
 511   case _C_ARY_B:
 512     while (isdigit ((unsigned char)*++type))
 513       /* do nothing */;
 514     return objc_alignof_type (type);
 515
 516   case _C_VECTOR:
 517     {
 518       /* Skip the '!'.  */
 519       type++;
 520       /* Skip the '['.  */
 521       type++;
 522
 523       /* Skip the size.  */
 524       while (isdigit ((unsigned char)*type))
 525         type++;
 526
 527       /* Skip the ','.  */
 528       type++;
 529
 530       /* The alignment in bytes is the following number.  */
 531       return atoi (type);
 532     }
 533   case _C_STRUCT_B:
 534   case _C_UNION_B:
 535     {
 536       struct objc_struct_layout layout;
 537       unsigned int align;
 538
 539       objc_layout_structure (type, &layout);
 540       while (objc_layout_structure_next_member (&layout))
 541         /* do nothing */;
 542       objc_layout_finish_structure (&layout, NULL, &align);
 543
 544       return align;
 545     }
 546
 547
 548   case _C_COMPLEX:
 549     {
 550       type++; /* Skip after the 'j'. */
 551       switch (*type)
 552         {
 553             case _C_CHR:
 554               return __alignof__ (_Complex char);
 555               break;
 556
 557             case _C_UCHR:
 558               return __alignof__ (_Complex unsigned char);
 559               break;
 560
 561             case _C_SHT:
 562               return __alignof__ (_Complex short);
 563               break;
 564
 565             case _C_USHT:
 566               return __alignof__ (_Complex unsigned short);
 567               break;
 568
 569             case _C_INT:
 570               return __alignof__ (_Complex int);
 571               break;
 572
 573             case _C_UINT:
 574               return __alignof__ (_Complex unsigned int);
 575               break;
 576
 577             case _C_LNG:
 578               return __alignof__ (_Complex long);
 579               break;
 580
 581             case _C_ULNG:
 582               return __alignof__ (_Complex unsigned long);
 583               break;
 584
 585             case _C_LNG_LNG:
 586               return __alignof__ (_Complex long long);
 587               break;
 588
 589             case _C_ULNG_LNG:
 590               return __alignof__ (_Complex unsigned long long);
 591               break;
 592
 593             case _C_FLT:
 594               return __alignof__ (_Complex float);
 595               break;
 596
 597             case _C_DBL:
 598               return __alignof__ (_Complex double);
 599               break;
 600
 601             case _C_LNG_DBL:
 602               return __alignof__ (_Complex long double);
 603               break;
 604
 605             default:
 606               {
 607                 _objc_abort ("unknown complex type %s\n", type);
 608                 return 0;
 609               }
 610         }
 611     }
 612
 613   default:
 614     {
 615       _objc_abort ("unknown type %s\n", type);
 616       return 0;
 617     }
 618   }
 619 }
 620
 621 int
 622 objc_aligned_size (const char *type)
 623 {
 624   int size, align;
 625
 626   type = objc_skip_variable_name (type);
 627   size = objc_sizeof_type (type);
 628   align = objc_alignof_type (type);
 629
 630   return ROUND (size, align);
 631 }
 632
 633 int
 634 objc_promoted_size (const char *type)
 635 {
 636   int size, wordsize;
 637
 638   type = objc_skip_variable_name (type);
 639   size = objc_sizeof_type (type);
 640   wordsize = sizeof (void *);
 641
 642   return ROUND (size, wordsize);
 643 }
 644
 645 inline
 646 const char *
 647 objc_skip_type_qualifiers (const char *type)
 648 {
 649   while (*type == _C_CONST
 650          || *type == _C_IN
 651          || *type == _C_INOUT
 652          || *type == _C_OUT
 653          || *type == _C_BYCOPY
 654          || *type == _C_BYREF
 655          || *type == _C_ONEWAY
 656          || *type == _C_GCINVISIBLE)
 657     {
 658       type += 1;
 659     }
 660   return type;
 661 }
 662
 663 inline
 664 const char *
 665 objc_skip_typespec (const char *type)
 666 {
 667   type = objc_skip_variable_name (type);
 668   type = objc_skip_type_qualifiers (type);
 669
 670   switch (*type) {
 671
 672   case _C_ID:
 673     /* An id may be annotated by the actual type if it is known
 674        with the @"ClassName" syntax */
 675
 676     if (*++type != '"')
 677       return type;
 678     else
 679       {
 680         while (*++type != '"')
 681           /* do nothing */;
 682         return type + 1;
 683       }
 684
 685     /* The following are one character type codes */
 686   case _C_CLASS:
 687   case _C_SEL:
 688   case _C_CHR:
 689   case _C_UCHR:
 690   case _C_CHARPTR:
 691   case _C_ATOM:
 692   case _C_SHT:
 693   case _C_USHT:
 694   case _C_INT:
 695   case _C_UINT:
 696   case _C_LNG:
 697   case _C_BOOL:
 698   case _C_ULNG:
 699   case _C_LNG_LNG:
 700   case _C_ULNG_LNG:
 701   case _C_FLT:
 702   case _C_DBL:
 703   case _C_LNG_DBL:
 704   case _C_VOID:
 705   case _C_UNDEF:
 706     return ++type;
 707     break;
 708
 709   case _C_COMPLEX:
 710     return type + 2;
 711     break;
 712
 713   case _C_ARY_B:
 714     /* skip digits, typespec and closing ']' */
 715     while (isdigit ((unsigned char)*++type))
 716       ;
 717     type = objc_skip_typespec (type);
 718     if (*type == _C_ARY_E)
 719       return ++type;
 720     else
 721       {
 722         _objc_abort ("bad array type %s\n", type);
 723         return 0;
 724       }
 725
 726   case _C_VECTOR:
 727     /* Skip '!' */
 728     type++;
 729     /* Skip '[' */
 730     type++;
 731     /* Skip digits (size) */
 732     while (isdigit ((unsigned char)*type))
 733       type++;
 734     /* Skip ',' */
 735     type++;
 736     /* Skip digits (alignment) */
 737     while (isdigit ((unsigned char)*type))
 738       type++;
 739     /* Skip typespec.  */
 740     type = objc_skip_typespec (type);
 741     /* Skip closing ']'.  */
 742     if (*type == _C_ARY_E)
 743       return ++type;
 744     else
 745       {
 746         _objc_abort ("bad vector type %s\n", type);
 747         return 0;
 748       }
 749
 750   case _C_BFLD:
 751     /* The GNU encoding of bitfields is: b 'position' 'type'
 752        'size'.  */
 753     while (isdigit ((unsigned char)*++type))
 754       ; /* skip position */
 755     while (isdigit ((unsigned char)*++type))
 756       ; /* skip type and size */
 757     return type;
 758
 759   case _C_STRUCT_B:
 760     /* skip name, and elements until closing '}'  */
 761
 762     while (*type != _C_STRUCT_E && *type++ != '=')
 763       ;
 764     while (*type != _C_STRUCT_E)
 765       {
 766         type = objc_skip_typespec (type);
 767       }
 768     return ++type;
 769
 770   case _C_UNION_B:
 771     /* skip name, and elements until closing ')'  */
 772
 773     while (*type != _C_UNION_E && *type++ != '=')
 774       ;
 775     while (*type != _C_UNION_E)
 776       {
 777         type = objc_skip_typespec (type);
 778       }
 779     return ++type;
 780
 781   case _C_PTR:
 782     /* Just skip the following typespec */
 783
 784     return objc_skip_typespec (++type);
 785
 786   default:
 787     {
 788       _objc_abort ("unknown type %s\n", type);
 789       return 0;
 790     }
 791   }
 792 }
 793
 794 inline
 795 const char *
 796 objc_skip_offset (const char *type)
 797 {
 798   /* The offset is prepended by a '+' if the argument is passed in
 799      registers.  PS: The compiler stopped generating this '+' in
 800      version 3.4.  */
 801   if (*type == '+')
 802     type++;
 803
 804   /* Some people claim that on some platforms, where the stack grows
 805      backwards, the compiler generates negative offsets (??).  Skip a
 806      '-' for such a negative offset.  */
 807   if (*type == '-')
 808     type++;
 809
 810   /* Skip the digits that represent the offset.  */
 811   while (isdigit ((unsigned char) *type))
 812     type++;
 813
 814   return type;
 815 }
 816
 817 const char *
 818 objc_skip_argspec (const char *type)
 819 {
 820   type = objc_skip_typespec (type);
 821   type = objc_skip_offset (type);
 822   return type;
 823 }
 824
 825 char *
 826 method_copyReturnType (struct objc_method *method)
 827 {
 828   if (method == NULL)
 829     return 0;
 830   else
 831     {
 832       char *returnValue;
 833       size_t returnValueSize;
 834
 835       /* Determine returnValueSize.  */
 836       {
 837         /* Find the end of the first argument.  We want to return the
 838            first argument spec, plus 1 byte for the \0 at the end.  */
 839         const char *type = method->method_types;
 840         if (*type == '\0')
 841           return NULL;
 842         type = objc_skip_argspec (type);
 843         returnValueSize = type - method->method_types + 1;
 844       }
 845
 846       /* Copy the first argument into returnValue.  */
 847       returnValue = malloc (sizeof (char) * returnValueSize);
 848       memcpy (returnValue, method->method_types, returnValueSize);
 849       returnValue[returnValueSize - 1] = '\0';
 850
 851       return returnValue;
 852     }
 853 }
 854
 855 char *
 856 method_copyArgumentType (struct objc_method * method, unsigned int argumentNumber)
 857 {
 858   if (method == NULL)
 859     return 0;
 860   else
 861     {
 862       char *returnValue;
 863       const char *returnValueStart;
 864       size_t returnValueSize;
 865
 866       /* Determine returnValueStart and returnValueSize.  */
 867       {
 868         const char *type = method->method_types;
 869
 870         /* Skip the first argument (return type).  */
 871         type = objc_skip_argspec (type);
 872
 873         /* Now keep skipping arguments until we get to
 874            argumentNumber.  */
 875         while (argumentNumber > 0)
 876           {
 877             /* We are supposed to skip an argument, but the string is
 878                finished.  This means we were asked for a non-existing
 879                argument.  */
 880             if (*type == '\0')
 881               return NULL;
 882
 883             type = objc_skip_argspec (type);
 884             argumentNumber--;
 885           }
 886
 887         /* If the argument does not exist, return NULL.  */
 888         if (*type == '\0')
 889           return NULL;
 890
 891         returnValueStart = type;
 892         type = objc_skip_argspec (type);
 893         returnValueSize = type - returnValueStart + 1;
 894       }
 895
 896       /* Copy the argument into returnValue.  */
 897       returnValue = malloc (sizeof (char) * returnValueSize);
 898       memcpy (returnValue, returnValueStart, returnValueSize);
 899       returnValue[returnValueSize - 1] = '\0';
 900
 901       return returnValue;
 902     }
 903 }
 904
 905 void method_getReturnType (struct objc_method * method, char *returnValue,
 906                            size_t returnValueSize)
 907 {
 908   if (returnValue == NULL  ||  returnValueSize == 0)
 909     return;
 910
 911   /* Zero the string; we'll then write the argument type at the
 912      beginning of it, if needed.  */
 913   memset (returnValue, 0, returnValueSize);
 914
 915   if (method == NULL)
 916     return;
 917   else
 918     {
 919       size_t argumentTypeSize;
 920
 921       /* Determine argumentTypeSize.  */
 922       {
 923         /* Find the end of the first argument.  We want to return the
 924            first argument spec.  */
 925         const char *type = method->method_types;
 926         if (*type == '\0')
 927           return;
 928         type = objc_skip_argspec (type);
 929         argumentTypeSize = type - method->method_types;
 930         if (argumentTypeSize > returnValueSize)
 931           argumentTypeSize = returnValueSize;
 932       }
 933       /* Copy the argument at the beginning of the string.  */
 934       memcpy (returnValue, method->method_types, argumentTypeSize);
 935     }
 936 }
 937
 938 void method_getArgumentType (struct objc_method * method, unsigned int argumentNumber,
 939                              char *returnValue, size_t returnValueSize)
 940 {
 941   if (returnValue == NULL  ||  returnValueSize == 0)
 942     return;
 943
 944   /* Zero the string; we'll then write the argument type at the
 945      beginning of it, if needed.  */
 946   memset (returnValue, 0, returnValueSize);
 947
 948   if (method == NULL)
 949     return;
 950   else
 951     {
 952       const char *returnValueStart;
 953       size_t argumentTypeSize;
 954
 955       /* Determine returnValueStart and argumentTypeSize.  */
 956       {
 957         const char *type = method->method_types;
 958
 959         /* Skip the first argument (return type).  */
 960         type = objc_skip_argspec (type);
 961
 962         /* Now keep skipping arguments until we get to
 963            argumentNumber.  */
 964         while (argumentNumber > 0)
 965           {
 966             /* We are supposed to skip an argument, but the string is
 967                finished.  This means we were asked for a non-existing
 968                argument.  */
 969             if (*type == '\0')
 970               return;
 971
 972             type = objc_skip_argspec (type);
 973             argumentNumber--;
 974           }
 975
 976         /* If the argument does not exist, it's game over.  */
 977         if (*type == '\0')
 978           return;
 979
 980         returnValueStart = type;
 981         type = objc_skip_argspec (type);
 982         argumentTypeSize = type - returnValueStart;
 983         if (argumentTypeSize > returnValueSize)
 984           argumentTypeSize = returnValueSize;
 985       }
 986       /* Copy the argument at the beginning of the string.  */
 987       memcpy (returnValue, returnValueStart, argumentTypeSize);
 988     }
 989 }
 990
 991 unsigned int
 992 method_getNumberOfArguments (struct objc_method *method)
 993 {
 994   if (method == NULL)
 995     return 0;
 996   else
 997     {
 998       unsigned int i = 0;
 999       const char *type = method->method_types;
1000       while (*type)
1001         {
1002           type = objc_skip_argspec (type);
1003           i += 1;
1004         }
1005
1006       if (i == 0)
1007         {
1008           /* This could only happen if method_types is invalid; in
1009              that case, return 0.  */
1010           return 0;
1011         }
1012       else
1013         {
1014           /* Remove the return type.  */
1015           return (i - 1);
1016         }
1017     }
1018 }
1019
1020 unsigned
1021 objc_get_type_qualifiers (const char *type)
1022 {
1023   unsigned res = 0;
1024   BOOL flag = YES;
1025
1026   while (flag)
1027     switch (*type++)
1028       {
1029       case _C_CONST:       res |= _F_CONST; break;
1030       case _C_IN:          res |= _F_IN; break;
1031       case _C_INOUT:       res |= _F_INOUT; break;
1032       case _C_OUT:         res |= _F_OUT; break;
1033       case _C_BYCOPY:      res |= _F_BYCOPY; break;
1034       case _C_BYREF:       res |= _F_BYREF; break;
1035       case _C_ONEWAY:      res |= _F_ONEWAY; break;
1036       case _C_GCINVISIBLE: res |= _F_GCINVISIBLE; break;
1037       default: flag = NO;
1038     }
1039
1040   return res;
1041 }
1042
1043 /* The following three functions can be used to determine how a
1044    structure is laid out by the compiler. For example:
1045
1046   struct objc_struct_layout layout;
1047   int i;
1048
1049   objc_layout_structure (type, &layout);
1050   while (objc_layout_structure_next_member (&layout))
1051     {
1052       int position, align;
1053       const char *type;
1054
1055       objc_layout_structure_get_info (&layout, &position, &align, &type);
1056       printf ("element %d has offset %d, alignment %d\n",
1057               i++, position, align);
1058     }
1059
1060   These functions are used by objc_sizeof_type and objc_alignof_type
1061   functions to compute the size and alignment of structures. The
1062   previous method of computing the size and alignment of a structure
1063   was not working on some architectures, particularly on AIX, and in
1064   the presence of bitfields inside the structure.  */
1065 void
1066 objc_layout_structure (const char *type,
1067                        struct objc_struct_layout *layout)
1068 {
1069   const char *ntype;
1070
1071   if (*type != _C_UNION_B && *type != _C_STRUCT_B)
1072     {
1073       _objc_abort ("record (or union) type expected in objc_layout_structure, got %s\n",
1074                    type);
1075     }
1076
1077   type ++;
1078   layout->original_type = type;
1079
1080   /* Skip "<name>=" if any. Avoid embedded structures and unions. */
1081   ntype = type;
1082   while (*ntype != _C_STRUCT_E && *ntype != _C_STRUCT_B && *ntype != _C_UNION_B
1083          && *ntype++ != '=')
1084     /* do nothing */;
1085
1086   /* If there's a "<name>=", ntype - 1 points to '='; skip the the name */
1087   if (*(ntype - 1) == '=')
1088     type = ntype;
1089
1090   layout->type = type;
1091   layout->prev_type = NULL;
1092   layout->record_size = 0;
1093   layout->record_align = __CHAR_BIT__;
1094
1095   layout->record_align = MAX (layout->record_align, STRUCTURE_SIZE_BOUNDARY);
1096 }
1097
1098 BOOL
1099 objc_layout_structure_next_member (struct objc_struct_layout *layout)
1100 {
1101   register int desired_align = 0;
1102
1103   /* The following are used only if the field is a bitfield */
1104   register const char *bfld_type = 0;
1105   register int bfld_type_align = 0, bfld_field_size = 0;
1106
1107   /* The current type without the type qualifiers */
1108   const char *type;
1109   BOOL unionp = layout->original_type[-1] == _C_UNION_B;
1110
1111   /* Add the size of the previous field to the size of the record.  */
1112   if (layout->prev_type)
1113     {
1114       type = objc_skip_type_qualifiers (layout->prev_type);
1115       if (unionp)
1116         layout->record_size = MAX (layout->record_size,
1117                                    objc_sizeof_type (type) * __CHAR_BIT__);
1118
1119       else if (*type != _C_BFLD)
1120         layout->record_size += objc_sizeof_type (type) * __CHAR_BIT__;
1121       else {
1122         /* Get the bitfield's type */
1123         for (bfld_type = type + 1;
1124              isdigit ((unsigned char)*bfld_type);
1125              bfld_type++)
1126           /* do nothing */;
1127
1128         bfld_type_align = objc_alignof_type (bfld_type) * __CHAR_BIT__;
1129         bfld_field_size = atoi (objc_skip_typespec (bfld_type));
1130         layout->record_size += bfld_field_size;
1131       }
1132     }
1133
1134   if ((unionp && *layout->type == _C_UNION_E)
1135       || (!unionp && *layout->type == _C_STRUCT_E))
1136     return NO;
1137
1138   /* Skip the variable name if any */
1139   layout->type = objc_skip_variable_name (layout->type);
1140   type = objc_skip_type_qualifiers (layout->type);
1141
1142   if (*type != _C_BFLD)
1143     desired_align = objc_alignof_type (type) * __CHAR_BIT__;
1144   else
1145     {
1146       desired_align = 1;
1147       /* Skip the bitfield's offset */
1148       for (bfld_type = type + 1;
1149            isdigit ((unsigned char) *bfld_type);
1150            bfld_type++)
1151         /* do nothing */;
1152
1153       bfld_type_align = objc_alignof_type (bfld_type) * __CHAR_BIT__;
1154       bfld_field_size = atoi (objc_skip_typespec (bfld_type));
1155     }
1156
1157   /* The following won't work for vectors.  */
1158 #ifdef BIGGEST_FIELD_ALIGNMENT
1159   desired_align = MIN (desired_align, BIGGEST_FIELD_ALIGNMENT);
1160 #endif
1161 #ifdef ADJUST_FIELD_ALIGN
1162   desired_align = ADJUST_FIELD_ALIGN (type, type, desired_align);
1163 #endif
1164
1165   /* Record must have at least as much alignment as any field.
1166      Otherwise, the alignment of the field within the record
1167      is meaningless.  */
1168 #ifndef HAVE_BITFIELD_TYPE_MATTERS
1169   layout->record_align = MAX (layout->record_align, desired_align);
1170 #else   /* PCC_BITFIELD_TYPE_MATTERS */
1171   if (*type == _C_BFLD)
1172     {
1173       /* For these machines, a zero-length field does not
1174          affect the alignment of the structure as a whole.
1175          It does, however, affect the alignment of the next field
1176          within the structure.  */
1177       if (bfld_field_size)
1178         layout->record_align = MAX (layout->record_align, desired_align);
1179       else
1180         desired_align = objc_alignof_type (bfld_type) * __CHAR_BIT__;
1181
1182       /* A named bit field of declared type `int'
1183          forces the entire structure to have `int' alignment.
1184          Q1: How is encoded this thing and how to check for it?
1185          Q2: How to determine maximum_field_alignment at runtime? */
1186
1187 /*        if (DECL_NAME (field) != 0) */
1188       {
1189         int type_align = bfld_type_align;
1190 #if 0
1191         if (maximum_field_alignment != 0)
1192           type_align = MIN (type_align, maximum_field_alignment);
1193         else if (DECL_PACKED (field))
1194           type_align = MIN (type_align, __CHAR_BIT__);
1195 #endif
1196
1197         layout->record_align = MAX (layout->record_align, type_align);
1198       }
1199     }
1200   else
1201     layout->record_align = MAX (layout->record_align, desired_align);
1202 #endif  /* PCC_BITFIELD_TYPE_MATTERS */
1203
1204   /* Does this field automatically have alignment it needs
1205      by virtue of the fields that precede it and the record's
1206      own alignment?  */
1207
1208   if (*type == _C_BFLD)
1209     layout->record_size = atoi (type + 1);
1210   else if (layout->record_size % desired_align != 0)
1211     {
1212       /* No, we need to skip space before this field.
1213          Bump the cumulative size to multiple of field alignment.  */
1214       layout->record_size = ROUND (layout->record_size, desired_align);
1215     }
1216
1217   /* Jump to the next field in record. */
1218
1219   layout->prev_type = layout->type;
1220   layout->type = objc_skip_typespec (layout->type);      /* skip component */
1221
1222   return YES;
1223 }
1224
1225 void objc_layout_finish_structure (struct objc_struct_layout *layout,
1226                                    unsigned int *size,
1227                                    unsigned int *align)
1228 {
1229   BOOL unionp = layout->original_type[-1] == _C_UNION_B;
1230   if (layout->type
1231       && ((!unionp && *layout->type == _C_STRUCT_E)
1232           || (unionp && *layout->type == _C_UNION_E)))
1233     {
1234       /* Work out the alignment of the record as one expression and store
1235          in the record type.  Round it up to a multiple of the record's
1236          alignment. */
1237 #if defined (ROUND_TYPE_ALIGN) && ! defined (__sparc__)
1238       layout->record_align = ROUND_TYPE_ALIGN (layout->original_type-1,
1239                                                1,
1240                                                layout->record_align);
1241 #else
1242       layout->record_align = MAX (1, layout->record_align);
1243 #endif
1244
1245       /* Round the size up to be a multiple of the required alignment */
1246       layout->record_size = ROUND (layout->record_size, layout->record_align);
1247
1248       layout->type = NULL;
1249     }
1250   if (size)
1251     *size = layout->record_size / __CHAR_BIT__;
1252   if (align)
1253     *align = layout->record_align / __CHAR_BIT__;
1254 }
1255
1256 void objc_layout_structure_get_info (struct objc_struct_layout *layout,
1257                                      unsigned int *offset,
1258                                      unsigned int *align,
1259                                      const char **type)
1260 {
1261   if (offset)
1262     *offset = layout->record_size / __CHAR_BIT__;
1263   if (align)
1264     *align = layout->record_align / __CHAR_BIT__;
1265   if (type)
1266     *type = layout->prev_type;
1267 }