gcc/objc/objc-encoding.c

   1 /* Routines dealing with ObjC encoding of types
   2    Copyright (C) 1992-2017 Free Software Foundation, Inc.
   3
   4 This file is part of GCC.
   5
   6 GCC is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 3, or (at your option)
   9 any later version.
  10
  11 GCC 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
  14 GNU General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GCC; see the file COPYING3.  If not see
  18 <http://www.gnu.org/licenses/>.  */
  19
  20 #include "config.h"
  21 #include "system.h"
  22 #include "coretypes.h"
  23 #include "tree.h"
  24 #include "options.h"
  25 #include "stringpool.h"
  26 #include "stor-layout.h"
  27
  28 #ifdef OBJCPLUS
  29 #include "cp/cp-tree.h"
  30 #else
  31 #include "c/c-tree.h"
  32 #include "c/c-lang.h"
  33 #endif
  34
  35 #include "c-family/c-objc.h"
  36
  37 #include "objc-encoding.h"
  38 #include "objc-act.h"
  39
  40 /* For my_build_string().  */
  41 #include "objc-runtime-shared-support.h"
  42
  43 /* For BITS_PER_UNIT.  */
  44
  45 /* When building Objective-C++, we are not linking against the C front-end
  46    and so need to replicate the C tree-construction functions in some way.  */
  47 #ifdef OBJCPLUS
  48 #define OBJCP_REMAP_FUNCTIONS
  49 #include "objcp-decl.h"
  50 #endif  /* OBJCPLUS */
  51
  52 /* Set up for use of obstacks.  */
  53
  54 /* This obstack is used to accumulate the encoding of a data type.  */
  55 static struct obstack util_obstack;
  56
  57 /* This points to the beginning of obstack contents, so we can free
  58    the whole contents.  */
  59 static char *util_firstobj;
  60
  61 void objc_encoding_init (void)
  62 {
  63   gcc_obstack_init (&util_obstack);
  64   util_firstobj = (char *) obstack_finish (&util_obstack);
  65 }
  66
  67 int generating_instance_variables = 0;
  68
  69 static void encode_type_qualifiers (tree);
  70 static void encode_type (tree, int, int);
  71 static void encode_field (tree field_decl, int curtype, int format);
  72
  73 static tree
  74 objc_method_parm_type (tree type)
  75 {
  76   type = TREE_VALUE (TREE_TYPE (type));
  77   if (TREE_CODE (type) == TYPE_DECL)
  78     type = TREE_TYPE (type);
  79   return type;
  80 }
  81
  82 static int
  83 objc_encoded_type_size (tree type)
  84 {
  85   int sz = int_size_in_bytes (type);
  86
  87   /* Make all integer and enum types at least as large
  88      as an int.  */
  89   if (sz > 0 && INTEGRAL_TYPE_P (type))
  90     sz = MAX (sz, int_size_in_bytes (integer_type_node));
  91   /* Treat arrays as pointers, since that's how they're
  92      passed in.  */
  93   else if (TREE_CODE (type) == ARRAY_TYPE)
  94     sz = int_size_in_bytes (ptr_type_node);
  95   return sz;
  96 }
  97
  98 /* Encode a method prototype.  */
  99 tree
 100 encode_method_prototype (tree method_decl)
 101 {
 102   tree parms;
 103   int parm_offset, i;
 104   char buf[40];
 105   tree result;
 106
 107   /* ONEWAY and BYCOPY, for remote object are the only method qualifiers.  */
 108   encode_type_qualifiers (TREE_PURPOSE (TREE_TYPE (method_decl)));
 109
 110   /* Encode return type.  */
 111   encode_type (objc_method_parm_type (method_decl),
 112                obstack_object_size (&util_obstack),
 113                OBJC_ENCODE_INLINE_DEFS);
 114
 115   /* Stack size.  */
 116   /* The first two arguments (self and _cmd) are pointers; account for
 117      their size.  */
 118   i = int_size_in_bytes (ptr_type_node);
 119   parm_offset = 2 * i;
 120   for (parms = METHOD_SEL_ARGS (method_decl); parms;
 121        parms = DECL_CHAIN (parms))
 122     {
 123       tree type = objc_method_parm_type (parms);
 124       int sz = objc_encoded_type_size (type);
 125
 126       /* If a type size is not known, bail out.  */
 127       if (sz < 0)
 128         {
 129           error_at (DECL_SOURCE_LOCATION (method_decl),
 130                     "type %qT does not have a known size",
 131                     type);
 132           /* Pretend that the encoding succeeded; the compilation will
 133              fail nevertheless.  */
 134           goto finish_encoding;
 135         }
 136       parm_offset += sz;
 137     }
 138
 139   sprintf (buf, "%d@0:%d", parm_offset, i);
 140   obstack_grow (&util_obstack, buf, strlen (buf));
 141
 142   /* Argument types.  */
 143   parm_offset = 2 * i;
 144   for (parms = METHOD_SEL_ARGS (method_decl); parms;
 145        parms = DECL_CHAIN (parms))
 146     {
 147       tree type = objc_method_parm_type (parms);
 148
 149       /* Process argument qualifiers for user supplied arguments.  */
 150       encode_type_qualifiers (TREE_PURPOSE (TREE_TYPE (parms)));
 151
 152       /* Type.  */
 153       encode_type (type, obstack_object_size (&util_obstack),
 154                    OBJC_ENCODE_INLINE_DEFS);
 155
 156       /* Compute offset.  */
 157       sprintf (buf, "%d", parm_offset);
 158       parm_offset += objc_encoded_type_size (type);
 159
 160       obstack_grow (&util_obstack, buf, strlen (buf));
 161     }
 162
 163   finish_encoding:
 164   obstack_1grow (&util_obstack, '\0');
 165   result = get_identifier (XOBFINISH (&util_obstack, char *));
 166   obstack_free (&util_obstack, util_firstobj);
 167   return result;
 168 }
 169
 170 /* This is used to implement @encode().  */
 171 tree
 172 objc_build_encode_expr (tree type)
 173 {
 174   tree result;
 175   const char *string;
 176
 177   encode_type (type, obstack_object_size (&util_obstack),
 178                OBJC_ENCODE_INLINE_DEFS);
 179   obstack_1grow (&util_obstack, 0);    /* null terminate string */
 180   string = XOBFINISH (&util_obstack, const char *);
 181
 182   /* Synthesize a string that represents the encoded struct/union.  */
 183   result = my_build_string (strlen (string) + 1, string);
 184   obstack_free (&util_obstack, util_firstobj);
 185   return result;
 186 }
 187
 188 /* "Encode" a data type into a string, which grows in util_obstack.
 189
 190    The format is described in gcc/doc/objc.texi, section 'Type
 191    encoding'.
 192
 193    Most of the encode_xxx functions have a 'type' argument, which is
 194    the type to encode, and an integer 'curtype' argument, which is the
 195    index in the encoding string of the beginning of the encoding of
 196    the current type, and allows you to find what characters have
 197    already been written for the current type (they are the ones in the
 198    current encoding string starting from 'curtype').
 199
 200    For example, if we are encoding a method which returns 'int' and
 201    takes a 'char **' argument, then when we get to the point of
 202    encoding the 'char **' argument, the encoded string already
 203    contains 'i12@0:4' (assuming a pointer size of 4 bytes).  So,
 204    'curtype' will be set to 7 when starting to encode 'char **'.
 205    During the whole of the encoding of 'char **', 'curtype' will be
 206    fixed at 7, so the routine encoding the second pointer can find out
 207    that it's actually encoding a pointer to a pointer by looking
 208    backwards at what has already been encoded for the current type,
 209    and seeing there is a "^" (meaning a pointer) in there.  */
 210
 211
 212 /* Encode type qualifiers encodes one of the "PQ" Objective-C
 213    keywords, ie 'in', 'out', 'inout', 'bycopy', 'byref', 'oneway'.
 214    'const', instead, is encoded directly as part of the type.  */
 215 static void
 216 encode_type_qualifiers (tree declspecs)
 217 {
 218   tree spec;
 219
 220   for (spec = declspecs; spec; spec = TREE_CHAIN (spec))
 221     {
 222       /* FIXME: Shouldn't we use token->keyword here ? */
 223       if (ridpointers[(int) RID_IN] == TREE_VALUE (spec))
 224         obstack_1grow (&util_obstack, 'n');
 225       else if (ridpointers[(int) RID_INOUT] == TREE_VALUE (spec))
 226         obstack_1grow (&util_obstack, 'N');
 227       else if (ridpointers[(int) RID_OUT] == TREE_VALUE (spec))
 228         obstack_1grow (&util_obstack, 'o');
 229       else if (ridpointers[(int) RID_BYCOPY] == TREE_VALUE (spec))
 230         obstack_1grow (&util_obstack, 'O');
 231       else if (ridpointers[(int) RID_BYREF] == TREE_VALUE (spec))
 232         obstack_1grow (&util_obstack, 'R');
 233       else if (ridpointers[(int) RID_ONEWAY] == TREE_VALUE (spec))
 234         obstack_1grow (&util_obstack, 'V');
 235       else
 236         gcc_unreachable ();
 237     }
 238 }
 239
 240 /* Determine if a pointee is marked read-only.  Only used by the NeXT
 241    runtime to be compatible with gcc-3.3.  */
 242 static bool
 243 pointee_is_readonly (tree pointee)
 244 {
 245   while (POINTER_TYPE_P (pointee))
 246     pointee = TREE_TYPE (pointee);
 247
 248   return TYPE_READONLY (pointee);
 249 }
 250
 251 /* Encode a pointer type.  */
 252 static void
 253 encode_pointer (tree type, int curtype, int format)
 254 {
 255   tree pointer_to = TREE_TYPE (type);
 256
 257   if (flag_next_runtime)
 258     {
 259       /* This code is used to be compatible with gcc-3.3.  */
 260       /* For historical/compatibility reasons, the read-only qualifier
 261          of the pointee gets emitted _before_ the '^'.  The read-only
 262          qualifier of the pointer itself gets ignored, _unless_ we are
 263          looking at a typedef!  Also, do not emit the 'r' for anything
 264          but the outermost type!  */
 265       if (!generating_instance_variables
 266           && (obstack_object_size (&util_obstack) - curtype <= 1)
 267           && (TYPE_NAME (type) && TREE_CODE (TYPE_NAME (type)) == TYPE_DECL
 268               ? TYPE_READONLY (type)
 269               : pointee_is_readonly (pointer_to)))
 270         obstack_1grow (&util_obstack, 'r');
 271     }
 272
 273   if (TREE_CODE (pointer_to) == RECORD_TYPE)
 274     {
 275       if (OBJC_TYPE_NAME (pointer_to)
 276           && TREE_CODE (OBJC_TYPE_NAME (pointer_to)) == IDENTIFIER_NODE)
 277         {
 278           const char *name = IDENTIFIER_POINTER (OBJC_TYPE_NAME (pointer_to));
 279
 280           if (strcmp (name, TAG_OBJECT) == 0) /* '@' */
 281             {
 282               obstack_1grow (&util_obstack, '@');
 283               return;
 284             }
 285           else if (TYPE_HAS_OBJC_INFO (pointer_to)
 286                    && TYPE_OBJC_INTERFACE (pointer_to))
 287             {
 288               if (generating_instance_variables)
 289                 {
 290                   obstack_1grow (&util_obstack, '@');
 291                   obstack_1grow (&util_obstack, '"');
 292                   obstack_grow (&util_obstack, name, strlen (name));
 293                   obstack_1grow (&util_obstack, '"');
 294                   return;
 295                 }
 296               else
 297                 {
 298                   obstack_1grow (&util_obstack, '@');
 299                   return;
 300                 }
 301             }
 302           else if (strcmp (name, TAG_CLASS) == 0) /* '#' */
 303             {
 304               obstack_1grow (&util_obstack, '#');
 305               return;
 306             }
 307           else if (strcmp (name, TAG_SELECTOR) == 0) /* ':' */
 308             {
 309               obstack_1grow (&util_obstack, ':');
 310               return;
 311             }
 312         }
 313     }
 314   else if (TREE_CODE (pointer_to) == INTEGER_TYPE
 315            && TYPE_MODE (pointer_to) == QImode)
 316     {
 317       tree pname = TREE_CODE (OBJC_TYPE_NAME (pointer_to)) == IDENTIFIER_NODE
 318                   ? OBJC_TYPE_NAME (pointer_to)
 319                   : DECL_NAME (OBJC_TYPE_NAME (pointer_to));
 320
 321       /* (BOOL *) are an exception and are encoded as ^c, while all
 322          other pointers to char are encoded as *.   */
 323       if (strcmp (IDENTIFIER_POINTER (pname), "BOOL"))
 324         {
 325           if (!flag_next_runtime)
 326             {
 327               /* The NeXT runtime adds the 'r' before getting here.  */
 328
 329               /* It appears that "r*" means "const char *" rather than
 330                  "char *const".  "char *const" is encoded as "*",
 331                  which is identical to "char *", so the "const" is
 332                  unfortunately lost.  */
 333               if (TYPE_READONLY (pointer_to))
 334                 obstack_1grow (&util_obstack, 'r');
 335             }
 336
 337           obstack_1grow (&util_obstack, '*');
 338           return;
 339         }
 340     }
 341
 342   /* We have a normal pointer type that does not get special treatment.  */
 343   obstack_1grow (&util_obstack, '^');
 344   encode_type (pointer_to, curtype, format);
 345 }
 346
 347 static void
 348 encode_array (tree type, int curtype, int format)
 349 {
 350   tree an_int_cst = TYPE_SIZE (type);
 351   tree array_of = TREE_TYPE (type);
 352   char buffer[40];
 353
 354   if (an_int_cst == NULL)
 355     {
 356       /* We are trying to encode an incomplete array.  An incomplete
 357          array is forbidden as part of an instance variable; but it
 358          may occur if the instance variable is a pointer to such an
 359          array.  */
 360
 361       /* So the only case in which an incomplete array could occur
 362          (without being pointed to) is if we are encoding the
 363          arguments or return value of a method.  In that case, an
 364          incomplete array argument or return value (eg,
 365          -(void)display: (char[])string) is treated like a pointer
 366          because that is how the compiler does the function call.  A
 367          special, more complicated case, is when the incomplete array
 368          is the last member of a struct (eg, if we are encoding
 369          "struct { unsigned long int a;double b[];}"), which is again
 370          part of a method argument/return value.  In that case, we
 371          really need to communicate to the runtime that there is an
 372          incomplete array (not a pointer!) there.  So, we detect that
 373          special case and encode it as a zero-length array.
 374
 375          Try to detect that we are part of a struct.  We do this by
 376          searching for '=' in the type encoding for the current type.
 377          NB: This hack assumes that you can't use '=' as part of a C
 378          identifier.
 379       */
 380       {
 381         char *enc = (char *) obstack_base (&util_obstack) + curtype;
 382         if (memchr (enc, '=',
 383                     obstack_object_size (&util_obstack) - curtype) == NULL)
 384           {
 385             /* We are not inside a struct.  Encode the array as a
 386                pointer.  */
 387             encode_pointer (type, curtype, format);
 388             return;
 389           }
 390       }
 391
 392       /* Else, we are in a struct, and we encode it as a zero-length
 393          array.  */
 394       sprintf (buffer, "[" HOST_WIDE_INT_PRINT_DEC, (HOST_WIDE_INT)0);
 395     }
 396   else if (TREE_INT_CST_LOW (TYPE_SIZE (array_of)) == 0)
 397    sprintf (buffer, "[" HOST_WIDE_INT_PRINT_DEC, (HOST_WIDE_INT)0);
 398   else
 399     sprintf (buffer, "[" HOST_WIDE_INT_PRINT_DEC,
 400              TREE_INT_CST_LOW (an_int_cst)
 401               / TREE_INT_CST_LOW (TYPE_SIZE (array_of)));
 402
 403   obstack_grow (&util_obstack, buffer, strlen (buffer));
 404   encode_type (array_of, curtype, format);
 405   obstack_1grow (&util_obstack, ']');
 406   return;
 407 }
 408
 409 /* Encode a vector.  The vector type is a GCC extension to C.  */
 410 static void
 411 encode_vector (tree type, int curtype, int format)
 412 {
 413   tree vector_of = TREE_TYPE (type);
 414   char buffer[40];
 415
 416   /* Vectors are like simple fixed-size arrays.  */
 417
 418   /* Output ![xx,yy,<code>] where xx is the vector_size, yy is the
 419      alignment of the vector, and <code> is the base type.  Eg, int
 420      __attribute__ ((vector_size (16))) gets encoded as ![16,32,i]
 421      assuming that the alignment is 32 bytes.  We include size and
 422      alignment in bytes so that the runtime does not have to have any
 423      knowledge of the actual types.
 424   */
 425   sprintf (buffer, "![" HOST_WIDE_INT_PRINT_DEC ",%d",
 426            /* We want to compute the equivalent of sizeof (<vector>).
 427               Code inspired by c_sizeof_or_alignof_type.  */
 428            ((TREE_INT_CST_LOW (TYPE_SIZE_UNIT (type))
 429              / (TYPE_PRECISION (char_type_node) / BITS_PER_UNIT))),
 430            /* We want to compute the equivalent of __alignof__
 431               (<vector>).  Code inspired by
 432               c_sizeof_or_alignof_type.  */
 433            TYPE_ALIGN_UNIT (type));
 434   obstack_grow (&util_obstack, buffer, strlen (buffer));
 435   encode_type (vector_of, curtype, format);
 436   obstack_1grow (&util_obstack, ']');
 437   return;
 438 }
 439
 440 static void
 441 encode_aggregate_fields (tree type, bool pointed_to, int curtype, int format)
 442 {
 443   tree field = TYPE_FIELDS (type);
 444
 445   for (; field; field = DECL_CHAIN (field))
 446     {
 447 #ifdef OBJCPLUS
 448       /* C++ static members, and things that are not field at all,
 449          should not appear in the encoding.  */
 450       if (TREE_CODE (field) != FIELD_DECL || TREE_STATIC (field))
 451         continue;
 452 #endif
 453
 454       /* Recursively encode fields of embedded base classes.  */
 455       if (DECL_ARTIFICIAL (field) && !DECL_NAME (field)
 456           && TREE_CODE (TREE_TYPE (field)) == RECORD_TYPE)
 457         {
 458           encode_aggregate_fields (TREE_TYPE (field),
 459                                    pointed_to, curtype, format);
 460           continue;
 461         }
 462
 463       if (generating_instance_variables && !pointed_to)
 464         {
 465           tree fname = DECL_NAME (field);
 466
 467           obstack_1grow (&util_obstack, '"');
 468
 469           if (fname && TREE_CODE (fname) == IDENTIFIER_NODE)
 470             obstack_grow (&util_obstack,
 471                           IDENTIFIER_POINTER (fname),
 472                           strlen (IDENTIFIER_POINTER (fname)));
 473
 474           obstack_1grow (&util_obstack, '"');
 475         }
 476
 477       encode_field (field, curtype, format);
 478     }
 479 }
 480
 481 static void
 482 encode_aggregate_within (tree type, int curtype, int format, int left,
 483                          int right)
 484 {
 485   tree name;
 486   /* NB: aggregates that are pointed to have slightly different encoding
 487      rules in that you never encode the names of instance variables.  */
 488   int ob_size = obstack_object_size (&util_obstack);
 489   bool inline_contents = false;
 490   bool pointed_to = false;
 491
 492   if (flag_next_runtime)
 493     {
 494       if (ob_size > 0
 495           && *((char *) obstack_next_free (&util_obstack) - 1) == '^')
 496         pointed_to = true;
 497
 498       if ((format == OBJC_ENCODE_INLINE_DEFS || generating_instance_variables)
 499           && (!pointed_to || ob_size - curtype == 1
 500               || (ob_size - curtype == 2
 501                   && *((char *) obstack_next_free (&util_obstack) - 2) == 'r')))
 502         inline_contents = true;
 503     }
 504   else
 505     {
 506       /* c0 and c1 are the last two characters in the encoding of the
 507          current type; if the last two characters were '^' or '^r',
 508          then we are encoding an aggregate that is "pointed to".  The
 509          comment above applies: in that case we should avoid encoding
 510          the names of instance variables.
 511       */
 512       char c0, c1;
 513
 514       c1 = ob_size > 1 ? *((char *) obstack_next_free (&util_obstack) - 2) : 0;
 515       c0 = ob_size > 0 ? *((char *) obstack_next_free (&util_obstack) - 1) : 0;
 516       if (c0 == '^' || (c1 == '^' && c0 == 'r'))
 517         pointed_to = true;
 518
 519       if (format == OBJC_ENCODE_INLINE_DEFS || generating_instance_variables)
 520         {
 521           if (!pointed_to)
 522             inline_contents = true;
 523           else
 524             {
 525               /* Note that the check (ob_size - curtype < 2) prevents
 526                  infinite recursion when encoding a structure which is
 527                  a linked list (eg, struct node { struct node *next;
 528                  }).  Each time we follow a pointer, we add one
 529                  character to ob_size, and curtype is fixed, so after
 530                  at most two pointers we stop inlining contents and
 531                  break the loop.
 532
 533                  The other case where we don't inline is "^r", which
 534                  is a pointer to a constant struct.
 535               */
 536               if ((ob_size - curtype <= 2) && !(c0 == 'r'))
 537                 inline_contents = true;
 538             }
 539         }
 540     }
 541
 542   /* Traverse struct aliases; it is important to get the
 543      original struct and its tag name (if any).  */
 544   type = TYPE_MAIN_VARIANT (type);
 545   name = OBJC_TYPE_NAME (type);
 546   /* Open parenth/bracket.  */
 547   obstack_1grow (&util_obstack, left);
 548
 549   /* Encode the struct/union tag name, or '?' if a tag was
 550      not provided.  Typedef aliases do not qualify.  */
 551 #ifdef OBJCPLUS
 552   /* For compatibility with the NeXT runtime, ObjC++ encodes template
 553      args as a composite struct tag name. */
 554   if (name && TREE_CODE (name) == IDENTIFIER_NODE
 555       /* Did this struct have a tag?  */
 556       && !TYPE_WAS_UNNAMED (type))
 557     obstack_grow (&util_obstack,
 558                   decl_as_string (type, TFF_DECL_SPECIFIERS | TFF_UNQUALIFIED_NAME),
 559                   strlen (decl_as_string (type, TFF_DECL_SPECIFIERS | TFF_UNQUALIFIED_NAME)));
 560 #else
 561   if (name && TREE_CODE (name) == IDENTIFIER_NODE)
 562     obstack_grow (&util_obstack,
 563                   IDENTIFIER_POINTER (name),
 564                   strlen (IDENTIFIER_POINTER (name)));
 565 #endif
 566   else
 567     obstack_1grow (&util_obstack, '?');
 568
 569   /* Encode the types (and possibly names) of the inner fields,
 570      if required.  */
 571   if (inline_contents)
 572     {
 573       obstack_1grow (&util_obstack, '=');
 574       encode_aggregate_fields (type, pointed_to, curtype, format);
 575     }
 576   /* Close parenth/bracket.  */
 577   obstack_1grow (&util_obstack, right);
 578 }
 579
 580 /* Encode a bitfield NeXT-style (i.e., without a bit offset or the underlying
 581    field type.  */
 582 static void
 583 encode_next_bitfield (int width)
 584 {
 585   char buffer[40];
 586   sprintf (buffer, "b%d", width);
 587   obstack_grow (&util_obstack, buffer, strlen (buffer));
 588 }
 589
 590 /* Encodes 'type', ignoring type qualifiers (which you should encode
 591    beforehand if needed) with the exception of 'const', which is
 592    encoded by encode_type.  See above for the explanation of
 593    'curtype'.  'format' can be OBJC_ENCODE_INLINE_DEFS or
 594    OBJC_ENCODE_DONT_INLINE_DEFS.  */
 595 static void
 596 encode_type (tree type, int curtype, int format)
 597 {
 598   enum tree_code code = TREE_CODE (type);
 599
 600   /* Ignore type qualifiers other than 'const' when encoding a
 601      type.  */
 602
 603   if (type == error_mark_node)
 604     return;
 605
 606   if (!flag_next_runtime)
 607     {
 608       if (TYPE_READONLY (type))
 609         obstack_1grow (&util_obstack, 'r');
 610     }
 611
 612   switch (code)
 613     {
 614     case ENUMERAL_TYPE:
 615       if (flag_next_runtime)
 616         {
 617           /* Kludge for backwards-compatibility with gcc-3.3: enums
 618              are always encoded as 'i' no matter what type they
 619              actually are (!).  */
 620           obstack_1grow (&util_obstack, 'i');
 621           break;
 622         }
 623       /* Else, they are encoded exactly like the integer type that is
 624          used by the compiler to store them.  */
 625       /* FALLTHRU */
 626     case INTEGER_TYPE:
 627       {
 628         char c;
 629         switch (GET_MODE_BITSIZE (SCALAR_INT_TYPE_MODE (type)))
 630           {
 631           case 8:  c = TYPE_UNSIGNED (type) ? 'C' : 'c'; break;
 632           case 16: c = TYPE_UNSIGNED (type) ? 'S' : 's'; break;
 633           case 32:
 634             {
 635               tree int_type = type;
 636               if (flag_next_runtime)
 637                 {
 638                   /* Another legacy kludge for compatibility with
 639                      gcc-3.3: 32-bit longs are encoded as 'l' or 'L',
 640                      but not always.  For typedefs, we need to use 'i'
 641                      or 'I' instead if encoding a struct field, or a
 642                      pointer!  */
 643                   int_type =  ((!generating_instance_variables
 644                                 && (obstack_object_size (&util_obstack)
 645                                     == (unsigned) curtype))
 646                                ? TYPE_MAIN_VARIANT (type)
 647                                : type);
 648                 }
 649               if (int_type == long_unsigned_type_node
 650                   || int_type == long_integer_type_node)
 651                 c = TYPE_UNSIGNED (type) ? 'L' : 'l';
 652               else
 653                 c = TYPE_UNSIGNED (type) ? 'I' : 'i';
 654             }
 655             break;
 656           case 64:  c = TYPE_UNSIGNED (type) ? 'Q' : 'q'; break;
 657           case 128: c = TYPE_UNSIGNED (type) ? 'T' : 't'; break;
 658           default: gcc_unreachable ();
 659           }
 660         obstack_1grow (&util_obstack, c);
 661         break;
 662       }
 663     case REAL_TYPE:
 664       {
 665         char c;
 666         /* Floating point types.  */
 667         switch (GET_MODE_BITSIZE (SCALAR_FLOAT_TYPE_MODE (type)))
 668           {
 669           case 32:  c = 'f'; break;
 670           case 64:  c = 'd'; break;
 671           case 96:
 672           case 128: c = 'D'; break;
 673           default: gcc_unreachable ();
 674           }
 675         obstack_1grow (&util_obstack, c);
 676         break;
 677       }
 678     case VOID_TYPE:
 679       obstack_1grow (&util_obstack, 'v');
 680       break;
 681
 682     case BOOLEAN_TYPE:
 683       obstack_1grow (&util_obstack, 'B');
 684       break;
 685
 686     case ARRAY_TYPE:
 687       encode_array (type, curtype, format);
 688       break;
 689
 690     case POINTER_TYPE:
 691 #ifdef OBJCPLUS
 692     case REFERENCE_TYPE:
 693 #endif
 694       encode_pointer (type, curtype, format);
 695       break;
 696
 697     case RECORD_TYPE:
 698       encode_aggregate_within (type, curtype, format, '{', '}');
 699       break;
 700
 701     case UNION_TYPE:
 702       encode_aggregate_within (type, curtype, format, '(', ')');
 703       break;
 704
 705     case FUNCTION_TYPE: /* '?' means an unknown type.  */
 706       obstack_1grow (&util_obstack, '?');
 707       break;
 708
 709     case COMPLEX_TYPE:
 710       /* A complex is encoded as 'j' followed by the inner type (eg,
 711          "_Complex int" is encoded as 'ji').  */
 712       obstack_1grow (&util_obstack, 'j');
 713       encode_type (TREE_TYPE (type), curtype, format);
 714       break;
 715
 716     case VECTOR_TYPE:
 717       encode_vector (type, curtype, format);
 718       break;
 719
 720     default:
 721       warning (0, "unknown type %<%T%> found during Objective-C encoding",
 722                TREE_TYPE (type));
 723       obstack_1grow (&util_obstack, '?');
 724       break;
 725     }
 726
 727   if (flag_next_runtime)
 728     {
 729       /* Super-kludge.  Some ObjC qualifier and type combinations need
 730          to be rearranged for compatibility with gcc-3.3.  */
 731       if (code == POINTER_TYPE && obstack_object_size (&util_obstack) >= 3)
 732         {
 733           char *enc = (char *) obstack_base (&util_obstack) + curtype;
 734
 735           /* Rewrite "in const" from "nr" to "rn".  */
 736           if (curtype >= 1 && !strncmp (enc - 1, "nr", 2))
 737             strncpy (enc - 1, "rn", 2);
 738         }
 739     }
 740 }
 741
 742 static void
 743 encode_gnu_bitfield (int position, tree type, int size)
 744 {
 745   enum tree_code code = TREE_CODE (type);
 746   char buffer[40];
 747   char charType = '?';
 748
 749   /* This code is only executed for the GNU runtime, so we can ignore
 750      the NeXT runtime kludge of always encoding enums as 'i' no matter
 751      what integers they actually are.  */
 752   if (code == INTEGER_TYPE  ||  code == ENUMERAL_TYPE)
 753     {
 754       if (integer_zerop (TYPE_MIN_VALUE (type)))
 755         /* Unsigned integer types.  */
 756         {
 757           switch (TYPE_MODE (type))
 758             {
 759             case E_QImode:
 760               charType = 'C'; break;
 761             case E_HImode:
 762               charType = 'S'; break;
 763             case E_SImode:
 764               {
 765                 if (type == long_unsigned_type_node)
 766                   charType = 'L';
 767                 else
 768                   charType = 'I';
 769                 break;
 770               }
 771             case E_DImode:
 772               charType = 'Q'; break;
 773             default:
 774               gcc_unreachable ();
 775             }
 776         }
 777       else
 778         /* Signed integer types.  */
 779         {
 780           switch (TYPE_MODE (type))
 781             {
 782             case E_QImode:
 783               charType = 'c'; break;
 784             case E_HImode:
 785               charType = 's'; break;
 786             case E_SImode:
 787               {
 788                 if (type == long_integer_type_node)
 789                   charType = 'l';
 790                 else
 791                   charType = 'i';
 792                 break;
 793               }
 794             case E_DImode:
 795               charType = 'q'; break;
 796             default:
 797               gcc_unreachable ();
 798             }
 799         }
 800     }
 801   else
 802     {
 803       /* Do not do any encoding, produce an error and keep going.  */
 804       error ("trying to encode non-integer type as a bitfield");
 805       return;
 806     }
 807
 808   sprintf (buffer, "b%d%c%d", position, charType, size);
 809   obstack_grow (&util_obstack, buffer, strlen (buffer));
 810 }
 811
 812 static void
 813 encode_field (tree field_decl, int curtype, int format)
 814 {
 815 #ifdef OBJCPLUS
 816   /* C++ static members, and things that are not fields at all,
 817      should not appear in the encoding.  */
 818   if (TREE_CODE (field_decl) != FIELD_DECL || TREE_STATIC (field_decl))
 819     return;
 820 #endif
 821
 822   /* Generate the bitfield typing information, if needed.  Note the difference
 823      between GNU and NeXT runtimes.  */
 824   if (DECL_BIT_FIELD_TYPE (field_decl))
 825     {
 826       int size = tree_to_uhwi (DECL_SIZE (field_decl));
 827
 828       if (flag_next_runtime)
 829         encode_next_bitfield (size);
 830       else
 831         encode_gnu_bitfield (int_bit_position (field_decl),
 832                              DECL_BIT_FIELD_TYPE (field_decl), size);
 833     }
 834   else
 835     encode_type (TREE_TYPE (field_decl), curtype, format);
 836 }
 837
 838 tree
 839 encode_field_decl (tree field_decl)
 840 {
 841   tree result;
 842
 843   encode_field (field_decl,
 844                 obstack_object_size (&util_obstack),
 845                 OBJC_ENCODE_DONT_INLINE_DEFS);
 846
 847   /* Null terminate string.  */
 848   obstack_1grow (&util_obstack, 0);
 849
 850   /* Get identifier for the string.  */
 851   result = get_identifier (XOBFINISH (&util_obstack, char *));
 852   obstack_free (&util_obstack, util_firstobj);
 853
 854   return result;
 855 }
 856
 857 /* This routine encodes the attribute of the input PROPERTY according
 858    to following formula:
 859
 860    Property attributes are stored as a comma-delimited C string.
 861    Simple attributes such as readonly are encoded as single
 862    character. The parametrized attributes, getter=name and
 863    setter=name, are encoded as a single character followed by an
 864    identifier.  Property types are also encoded as a parametrized
 865    attribute.  The characters used to encode these attributes are
 866    defined by the following enumeration:
 867
 868    enum PropertyAttributes {
 869      kPropertyReadOnly = 'R',
 870      kPropertyBycopy = 'C',
 871      kPropertyByref = '&',
 872      kPropertyDynamic = 'D',
 873      kPropertyGetter = 'G',
 874      kPropertySetter = 'S',
 875      kPropertyInstanceVariable = 'V',
 876      kPropertyType = 'T',
 877      kPropertyWeak = 'W',
 878      kPropertyStrong = 'P',
 879      kPropertyNonAtomic = 'N'
 880    };  */
 881 tree
 882 objc_v2_encode_prop_attr (tree property)
 883 {
 884   const char *string;
 885   tree type = TREE_TYPE (property);
 886
 887   obstack_1grow (&util_obstack, 'T');
 888   encode_type (type, obstack_object_size (&util_obstack),
 889                OBJC_ENCODE_INLINE_DEFS);
 890
 891   if (PROPERTY_READONLY (property))
 892     obstack_grow (&util_obstack, ",R", 2);
 893
 894   switch (PROPERTY_ASSIGN_SEMANTICS (property))
 895     {
 896     case OBJC_PROPERTY_COPY:
 897       obstack_grow (&util_obstack, ",C", 2);
 898       break;
 899     case OBJC_PROPERTY_RETAIN:
 900       obstack_grow (&util_obstack, ",&", 2);
 901       break;
 902     case OBJC_PROPERTY_ASSIGN:
 903     default:
 904       break;
 905     }
 906
 907   if (PROPERTY_DYNAMIC (property))
 908     obstack_grow (&util_obstack, ",D", 2);
 909
 910   if (PROPERTY_NONATOMIC (property))
 911     obstack_grow (&util_obstack, ",N", 2);
 912
 913   /* Here we want to encode the getter name, but only if it's not the
 914      standard one.  */
 915   if (PROPERTY_GETTER_NAME (property) != PROPERTY_NAME (property))
 916     {
 917       obstack_grow (&util_obstack, ",G", 2);
 918       string = IDENTIFIER_POINTER (PROPERTY_GETTER_NAME (property));
 919       obstack_grow (&util_obstack, string, strlen (string));
 920     }
 921
 922   if (!PROPERTY_READONLY (property))
 923     {
 924       /* Here we want to encode the setter name, but only if it's not
 925          the standard one.  */
 926       tree standard_setter = get_identifier (objc_build_property_setter_name (PROPERTY_NAME (property)));
 927       if (PROPERTY_SETTER_NAME (property) != standard_setter)
 928         {
 929           obstack_grow (&util_obstack, ",S", 2);
 930           string = IDENTIFIER_POINTER (PROPERTY_SETTER_NAME (property));
 931           obstack_grow (&util_obstack, string, strlen (string));
 932         }
 933     }
 934
 935   /* TODO: Encode strong ('P'), weak ('W') for garbage collection.  */
 936
 937   if (!PROPERTY_DYNAMIC (property))
 938     {
 939       obstack_grow (&util_obstack, ",V", 2);
 940       if (PROPERTY_IVAR_NAME (property))
 941         string = IDENTIFIER_POINTER (PROPERTY_IVAR_NAME (property));
 942       else
 943         string = IDENTIFIER_POINTER (PROPERTY_NAME (property));
 944       obstack_grow (&util_obstack, string, strlen (string));
 945     }
 946
 947   /* NULL-terminate string.  */
 948   obstack_1grow (&util_obstack, 0);
 949   string = XOBFINISH (&util_obstack, char *);
 950   obstack_free (&util_obstack, util_firstobj);
 951   return get_identifier (string);
 952 }