nsz Git - cparser/blob - attribute.c

   1 /*
   2  * This file is part of cparser.
   3  * Copyright (C) 2012 Matthias Braun <matze@braunis.de>
   4  */
   5 #include <config.h>
   6
   7 #include <assert.h>
   8 #include "adt/strutil.h"
   9 #include "diagnostic.h"
  10 #include "warning.h"
  11 #include "attribute_t.h"
  12 #include "symbol_t.h"
  13 #include "adt/error.h"
  14 #include "type_t.h"
  15
  16 static const char *const attribute_names[ATTRIBUTE_LAST+1] = {
  17         [ATTRIBUTE_GNU_ALIAS]                  = "alias",
  18         [ATTRIBUTE_GNU_ALIGNED]                = "aligned",
  19         [ATTRIBUTE_GNU_ALWAYS_INLINE]          = "always_inline",
  20         [ATTRIBUTE_GNU_CDECL]                  = "cdecl",
  21         [ATTRIBUTE_GNU_COMMON]                 = "common",
  22         [ATTRIBUTE_GNU_CONST]                  = "const",
  23         [ATTRIBUTE_GNU_CONSTRUCTOR]            = "constructor",
  24         [ATTRIBUTE_GNU_DEPRECATED]             = "deprecated",
  25         [ATTRIBUTE_GNU_DESTRUCTOR]             = "destructor",
  26         [ATTRIBUTE_GNU_DLLEXPORT]              = "dllexport",
  27         [ATTRIBUTE_GNU_DLLIMPORT]              = "dllimport",
  28         [ATTRIBUTE_GNU_EIGTHBIT_DATA]          = "eightbit_data",
  29         [ATTRIBUTE_GNU_EXTERNALLY_VISIBLE]     = "externally_visible",
  30         [ATTRIBUTE_GNU_FAR]                    = "far",
  31         [ATTRIBUTE_GNU_FASTCALL]               = "fastcall",
  32         [ATTRIBUTE_GNU_FLATTEN]                = "flatten",
  33         [ATTRIBUTE_GNU_FORMAT_ARG]             = "format_arg",
  34         [ATTRIBUTE_GNU_FORMAT]                 = "format",
  35         [ATTRIBUTE_GNU_FUNCTION_VECTOR]        = "function_vector",
  36         [ATTRIBUTE_GNU_GCC_STRUCT]             = "gcc_struct",
  37         [ATTRIBUTE_GNU_INTERRUPT_HANDLER]      = "interrupt_handler",
  38         [ATTRIBUTE_GNU_INTERRUPT]              = "interrupt",
  39         [ATTRIBUTE_GNU_LEAF]                   = "leaf",
  40         [ATTRIBUTE_GNU_LONGCALL]               = "longcall",
  41         [ATTRIBUTE_GNU_LONG_CALL]              = "long_call",
  42         [ATTRIBUTE_GNU_MALLOC]                 = "malloc",
  43         [ATTRIBUTE_GNU_MAY_ALIAS]              = "may_alias",
  44         [ATTRIBUTE_GNU_MODEL]                  = "model",
  45         [ATTRIBUTE_GNU_MODE]                   = "mode",
  46         [ATTRIBUTE_GNU_MS_STRUCT]              = "ms_struct",
  47         [ATTRIBUTE_GNU_NAKED]                  = "naked",
  48         [ATTRIBUTE_GNU_NEAR]                   = "near",
  49         [ATTRIBUTE_GNU_NESTING]                = "nesting",
  50         [ATTRIBUTE_GNU_NMI_HANDLER]            = "nmi_handler",
  51         [ATTRIBUTE_GNU_NOCOMMON]               = "nocommon",
  52         [ATTRIBUTE_GNU_NOINLINE]               = "noinline",
  53         [ATTRIBUTE_GNU_NO_INSTRUMENT_FUNCTION] = "no_instrument_function",
  54         [ATTRIBUTE_GNU_NONNULL]                = "nonnull",
  55         [ATTRIBUTE_GNU_NORETURN]               = "noreturn",
  56         [ATTRIBUTE_GNU_NOTHROW]                = "nothrow",
  57         [ATTRIBUTE_GNU_NOTSHARED]              = "notshared",
  58         [ATTRIBUTE_GNU_PACKED]                 = "packed",
  59         [ATTRIBUTE_GNU_PURE]                   = "pure",
  60         [ATTRIBUTE_GNU_REGPARM]                = "regparm",
  61         [ATTRIBUTE_GNU_RETURNS_TWICE]          = "returns_twice",
  62         [ATTRIBUTE_GNU_SAVEALL]                = "saveall",
  63         [ATTRIBUTE_GNU_SECTION]                = "section",
  64         [ATTRIBUTE_GNU_SENTINEL]               = "sentinel",
  65         [ATTRIBUTE_GNU_SHARED]                 = "shared",
  66         [ATTRIBUTE_GNU_SHORTCALL]              = "shortcall",
  67         [ATTRIBUTE_GNU_SHORT_CALL]             = "short_call",
  68         [ATTRIBUTE_GNU_SIGNAL]                 = "signal",
  69         [ATTRIBUTE_GNU_SP_SWITCH]              = "sp_switch",
  70         [ATTRIBUTE_GNU_SSEREGPARM]             = "sseregparm",
  71         [ATTRIBUTE_GNU_STDCALL]                = "stdcall",
  72         [ATTRIBUTE_GNU_TINY_DATA]              = "tiny_data",
  73         [ATTRIBUTE_GNU_TLS_MODEL]              = "tls_model",
  74         [ATTRIBUTE_GNU_TRANSPARENT_UNION]      = "transparent_union",
  75         [ATTRIBUTE_GNU_TRAP_EXIT]              = "trap_exit",
  76         [ATTRIBUTE_GNU_UNUSED]                 = "unused",
  77         [ATTRIBUTE_GNU_USED]                   = "used",
  78         [ATTRIBUTE_GNU_VISIBILITY]             = "visibility",
  79         [ATTRIBUTE_GNU_VOLATILE]               = "volatile",
  80         [ATTRIBUTE_GNU_WARN_UNUSED_RESULT]     = "warn_unused_result",
  81         [ATTRIBUTE_GNU_WEAKREF]                = "weakref",
  82         [ATTRIBUTE_GNU_WEAK]                   = "weak",
  83
  84         [ATTRIBUTE_MS_ALIGN]                   = "align",
  85         [ATTRIBUTE_MS_ALLOCATE]                = "allocate",
  86         [ATTRIBUTE_MS_DEPRECATED]              = "deprecated",
  87         [ATTRIBUTE_MS_DLLEXPORT]               = "dllexport",
  88         [ATTRIBUTE_MS_DLLIMPORT]               = "dllimport",
  89         [ATTRIBUTE_MS_NAKED]                   = "naked",
  90         [ATTRIBUTE_MS_NOALIAS]                 = "noalias",
  91         [ATTRIBUTE_MS_NOINLINE]                = "noinline",
  92         [ATTRIBUTE_MS_NORETURN]                = "noreturn",
  93         [ATTRIBUTE_MS_NOTHROW]                 = "nothrow",
  94         [ATTRIBUTE_MS_NOVTABLE]                = "novtable",
  95         [ATTRIBUTE_MS_PROPERTY]                = "property",
  96         [ATTRIBUTE_MS_RESTRICT]                = "restrict",
  97         [ATTRIBUTE_MS_RETURNS_TWICE]           = "returns_twice",
  98         [ATTRIBUTE_MS_SELECTANY]               = "selectany",
  99         [ATTRIBUTE_MS_THREAD]                  = "thread",
 100         [ATTRIBUTE_MS_UUID]                    = "uuid",
 101 };
 102
 103 const char *get_attribute_name(attribute_kind_t kind)
 104 {
 105         assert(kind <= ATTRIBUTE_LAST);
 106         return attribute_names[kind];
 107 }
 108
 109 type_t *handle_attribute_mode(const attribute_t *attribute, type_t *orig_type)
 110 {
 111         type_t *type = skip_typeref(orig_type);
 112
 113         /* at least: byte, word, pointer, list of machine modes
 114          * __XXX___ is interpreted as XXX */
 115
 116         /* This isn't really correct, the backend should provide a list of machine
 117          * specific modes (according to gcc philosophy that is...) */
 118         attribute_argument_t *arg = attribute->a.arguments;
 119         if (arg == NULL) {
 120                 errorf(&attribute->pos, "__attribute__((mode(X))) misses argument");
 121                 return orig_type;
 122         }
 123
 124         const char         *symbol_str = arg->v.symbol->string;
 125         bool                sign       = is_type_signed(type);
 126         atomic_type_kind_t  akind;
 127         if (streq_underscore("QI",   symbol_str) ||
 128             streq_underscore("byte", symbol_str)) {
 129                 akind = sign ? ATOMIC_TYPE_CHAR : ATOMIC_TYPE_UCHAR;
 130         } else if (streq_underscore("HI", symbol_str)) {
 131                 akind = sign ? ATOMIC_TYPE_SHORT : ATOMIC_TYPE_USHORT;
 132         } else if (streq_underscore("SI",      symbol_str)
 133                 || streq_underscore("word",    symbol_str)
 134                 || streq_underscore("pointer", symbol_str)) {
 135                 akind = sign ? ATOMIC_TYPE_INT : ATOMIC_TYPE_UINT;
 136         } else if (streq_underscore("DI", symbol_str)) {
 137                 akind = sign ? ATOMIC_TYPE_LONGLONG : ATOMIC_TYPE_ULONGLONG;
 138         } else {
 139                 warningf(WARN_OTHER, &attribute->pos, "ignoring unknown mode '%s'",
 140                          symbol_str);
 141                 return orig_type;
 142         }
 143
 144         if (type->kind == TYPE_ATOMIC || type->kind == TYPE_ENUM) {
 145                 type_t *copy       = duplicate_type(type);
 146                 copy->atomic.akind = akind;
 147                 return identify_new_type(copy);
 148         } else if (is_type_pointer(type)) {
 149                 warningf(WARN_OTHER, &attribute->pos, "__attribute__((mode)) on pointers not implemented yet (ignored)");
 150                 return type;
 151         }
 152
 153         errorf(&attribute->pos,
 154                "__attribute__((mode)) only allowed on integer, enum or pointer type");
 155         return orig_type;
 156 }
 157
 158 static inline bool is_po2(unsigned x)
 159 {
 160         return (x & (x-1)) == 0;
 161 }
 162
 163 static void handle_attribute_aligned(const attribute_t *attribute,
 164                                      entity_t *entity)
 165 {
 166         int alignment = 32; /* TODO: fill in maximum useful alignment for
 167                                                    target machine */
 168         if (attribute->a.arguments) {
 169                 attribute_argument_t *argument = attribute->a.arguments;
 170                 alignment = fold_constant_to_int(argument->v.expression);
 171         }
 172
 173         if (!is_po2(alignment)) {
 174                 errorf(&attribute->pos, "alignment must be a power of 2 but is %d", alignment);
 175                 return;
 176         }
 177         if (alignment <= 0) {
 178                 errorf(&attribute->pos, "alignment must be bigger than 0 but is %d", alignment);
 179                 return;
 180         }
 181
 182         switch (entity->kind) {
 183         case DECLARATION_KIND_CASES:
 184                 entity->declaration.alignment = alignment;
 185         case ENTITY_TYPEDEF:
 186                 entity->typedefe.alignment = alignment;
 187                 break;
 188         case ENTITY_STRUCT:
 189         case ENTITY_UNION:
 190                 if (alignment > (int)entity->compound.alignment) {
 191                         entity->compound.alignment = alignment;
 192                 }
 193                 break;
 194
 195         default:
 196                 warningf(WARN_OTHER, &attribute->pos, "alignment attribute specification on '%N' ignored", entity);
 197                 break;
 198         }
 199 }
 200
 201 static const char *get_argument_string(const attribute_argument_t *argument)
 202 {
 203         if (argument == NULL)
 204                 return NULL;
 205         if (argument->kind != ATTRIBUTE_ARGUMENT_EXPRESSION)
 206                 return NULL;
 207         expression_t *expression = argument->v.expression;
 208         if (expression->kind != EXPR_STRING_LITERAL)
 209                 return NULL;
 210         return expression->string_literal.value.begin;
 211 }
 212
 213 static void handle_attribute_visibility(const attribute_t *attribute,
 214                                         entity_t *entity)
 215 {
 216         /* This isn't really correct, the backend should provide a list of machine
 217          * specific modes (according to gcc philosophy that is...) */
 218         attribute_argument_t *arg = attribute->a.arguments;
 219         if (arg == NULL) {
 220                 errorf(&attribute->pos,
 221                        "__attribute__((visibility(X))) misses argument");
 222                 return;
 223         }
 224         const char *string = get_argument_string(arg);
 225         if (string == NULL) {
 226                 errorf(&attribute->pos,
 227                        "__attribute__((visibility(X))) argument is not a string");
 228                 return;
 229         }
 230         elf_visibility_tag_t visibility = get_elf_visibility_from_string(string);
 231         if (visibility == ELF_VISIBILITY_ERROR) {
 232                 errorf(&attribute->pos,
 233                        "unknown visibility type '%s'", string);
 234                 return;
 235         }
 236
 237         switch (entity->kind) {
 238         case ENTITY_VARIABLE:
 239                 entity->variable.elf_visibility = visibility;
 240                 break;
 241         case ENTITY_FUNCTION:
 242                 entity->function.elf_visibility = visibility;
 243                 break;
 244
 245         default:
 246                 warningf(WARN_OTHER, &attribute->pos, "visibility attribute specification on '%N' ignored", entity);
 247                 break;
 248         }
 249 }
 250
 251 static void warn_arguments(const attribute_t *attribute)
 252 {
 253         if (attribute->a.arguments == NULL)
 254                 return;
 255
 256         position_t const *const pos  = &attribute->pos;
 257         char       const *const what = get_attribute_name(attribute->kind);
 258         warningf(WARN_OTHER, pos, "attribute '%s' needs no arguments", what);
 259 }
 260
 261 static void handle_attribute_packed_e(const attribute_t *attribute,
 262                                       entity_t *entity)
 263 {
 264 #if 0
 265         if (entity->kind != ENTITY_STRUCT) {
 266                 warningf(WARN_OTHER, &attribute->pos, "packed attribute on '%N' ignored", entity);
 267                 return;
 268         }
 269 #endif
 270
 271         warn_arguments(attribute);
 272         entity->compound.packed = true;
 273 }
 274
 275 static void handle_attribute_packed(const attribute_t *attribute, type_t *type)
 276 {
 277         if (type->kind != TYPE_COMPOUND_STRUCT) {
 278                 position_t const *const pos  = &attribute->pos;
 279                 warningf(WARN_OTHER, pos, "packed attribute on type '%T' ignored", type);
 280                 return;
 281         }
 282
 283         handle_attribute_packed_e(attribute, (entity_t*) type->compound.compound);
 284 }
 285
 286 static void handle_attribute_asm(const attribute_t *attribute,
 287                                       entity_t *entity)
 288 {
 289         attribute_argument_t *argument = attribute->a.arguments;
 290         assert (argument->kind == ATTRIBUTE_ARGUMENT_EXPRESSION);
 291         expression_t *expression = argument->v.expression;
 292         if (expression->kind != EXPR_STRING_LITERAL)
 293                 errorf(&attribute->pos, "Invalid asm attribute expression");
 294         symbol_t *sym = symbol_table_insert(expression->string_literal.value.begin);
 295         entity->function.actual_name = sym;
 296         assert(argument->next == NULL);
 297         return;
 298 }
 299
 300 void handle_entity_attributes(const attribute_t *attributes, entity_t *entity)
 301 {
 302         if (entity->kind == ENTITY_TYPEDEF) {
 303                 type_t *type = entity->typedefe.type;
 304                 type = handle_type_attributes(attributes, type);
 305                 entity->typedefe.type = type;
 306         } else if (is_declaration(entity)) {
 307                 type_t *type = entity->declaration.type;
 308                 type = handle_type_attributes(attributes, type);
 309                 entity->declaration.type = type;
 310         }
 311
 312         decl_modifiers_t modifiers = 0;
 313         const attribute_t *attribute = attributes;
 314         for ( ; attribute != NULL; attribute = attribute->next) {
 315                 switch (attribute->kind) {
 316                 case ATTRIBUTE_GNU_CONST:         modifiers |= DM_CONST; break;
 317                 case ATTRIBUTE_GNU_DEPRECATED:    modifiers |= DM_DEPRECATED; break;
 318                 case ATTRIBUTE_GNU_NOINLINE:      modifiers |= DM_NOINLINE; break;
 319                 case ATTRIBUTE_GNU_NAKED:         modifiers |= DM_NAKED; break;
 320                 case ATTRIBUTE_GNU_PURE:          modifiers |= DM_PURE; break;
 321                 case ATTRIBUTE_GNU_ALWAYS_INLINE: modifiers |= DM_FORCEINLINE; break;
 322                 case ATTRIBUTE_GNU_CONSTRUCTOR:   modifiers |= DM_CONSTRUCTOR; break;
 323                 case ATTRIBUTE_GNU_DESTRUCTOR:    modifiers |= DM_DESTRUCTOR; break;
 324                 case ATTRIBUTE_GNU_TRANSPARENT_UNION:
 325                                                                                   modifiers |= DM_TRANSPARENT_UNION;
 326                                                                                   break;
 327                 case ATTRIBUTE_GNU_USED:          modifiers |= DM_USED; break;
 328                 case ATTRIBUTE_GNU_UNUSED:        modifiers |= DM_UNUSED; break;
 329                 case ATTRIBUTE_GNU_DLLIMPORT:     modifiers |= DM_DLLIMPORT; break;
 330                 case ATTRIBUTE_GNU_DLLEXPORT:     modifiers |= DM_DLLEXPORT; break;
 331                 case ATTRIBUTE_GNU_WEAK:          modifiers |= DM_WEAK; break;
 332                 case ATTRIBUTE_GNU_LEAF:          modifiers |= DM_LEAF; break;
 333
 334                 case ATTRIBUTE_MS_DLLIMPORT:     modifiers |= DM_DLLIMPORT; break;
 335                 case ATTRIBUTE_MS_DLLEXPORT:     modifiers |= DM_DLLEXPORT; break;
 336                 case ATTRIBUTE_MS_NAKED:         modifiers |= DM_NAKED; break;
 337                 case ATTRIBUTE_MS_NOINLINE:      modifiers |= DM_NOINLINE; break;
 338                 case ATTRIBUTE_MS_THREAD:        modifiers |= DM_THREAD; break;
 339                 case ATTRIBUTE_MS_DEPRECATED:    modifiers |= DM_DEPRECATED; break;
 340                 case ATTRIBUTE_MS_RESTRICT:      modifiers |= DM_RESTRICT; break;
 341                 case ATTRIBUTE_MS_NOALIAS:       modifiers |= DM_NOALIAS; break;
 342
 343                 case ATTRIBUTE_GNU_PACKED:
 344                         handle_attribute_packed_e(attribute, entity);
 345                         break;
 346
 347                 case ATTRIBUTE_GNU_ASM:
 348                         handle_attribute_asm(attribute, entity);
 349                         break;
 350
 351                 case ATTRIBUTE_GNU_VISIBILITY:
 352                         handle_attribute_visibility(attribute, entity);
 353                         break;
 354
 355                 case ATTRIBUTE_MS_ALIGN:
 356                 case ATTRIBUTE_GNU_ALIGNED:
 357                         handle_attribute_aligned(attribute, entity);
 358                         break;
 359                 default: break;
 360                 }
 361         }
 362
 363         if (modifiers != 0) {
 364                 switch (entity->kind) {
 365                 case ENTITY_TYPEDEF:
 366                         entity->typedefe.modifiers |= modifiers;
 367                         break;
 368                 case ENTITY_UNION:
 369                 case ENTITY_STRUCT:
 370                         entity->compound.modifiers |= modifiers;
 371                         break;
 372                 case ENTITY_COMPOUND_MEMBER:
 373                 case ENTITY_VARIABLE:
 374                 case ENTITY_FUNCTION:
 375                         entity->declaration.modifiers |= modifiers;
 376                         break;
 377                 default:
 378                         /* TODO: warning */
 379                         break;
 380                 }
 381         }
 382 }
 383
 384 static type_t *change_calling_convention(type_t *type, cc_kind_t cconv)
 385 {
 386         if (is_typeref(type) || !is_type_function(type)) {
 387                 return type;
 388         }
 389
 390         if (type->function.calling_convention == cconv)
 391                 return type;
 392
 393         type_t* new_type = duplicate_type(type);
 394         new_type->function.calling_convention = cconv;
 395         return identify_new_type(new_type);
 396 }
 397
 398 static type_t *add_modifiers(type_t *type, decl_modifiers_t modifiers)
 399 {
 400         if (is_typeref(type) || !is_type_function(type)) {
 401                 return type;
 402         }
 403
 404         if ((type->function.modifiers & modifiers) == modifiers)
 405                 return type;
 406
 407         type_t* new_type = duplicate_type(type);
 408         new_type->function.modifiers |= modifiers;
 409         return identify_new_type(new_type);
 410 }
 411
 412 type_t *handle_type_attributes(const attribute_t *attributes, type_t *type)
 413 {
 414         const attribute_t *attribute = attributes;
 415         for ( ; attribute != NULL; attribute = attribute->next) {
 416                 switch (attribute->kind) {
 417                 case ATTRIBUTE_GNU_PACKED:
 418                         handle_attribute_packed(attribute, type);
 419                         break;
 420                 case ATTRIBUTE_GNU_CDECL:
 421                 case ATTRIBUTE_MS_CDECL:
 422                         type = change_calling_convention(type, CC_CDECL);
 423                         break;
 424                 case ATTRIBUTE_MS_STDCALL:
 425                 case ATTRIBUTE_GNU_STDCALL:
 426                         type = change_calling_convention(type, CC_STDCALL);
 427                         break;
 428                 case ATTRIBUTE_MS_FASTCALL:
 429                 case ATTRIBUTE_GNU_FASTCALL:
 430                         type = change_calling_convention(type, CC_FASTCALL);
 431                         break;
 432                 case ATTRIBUTE_MS_THISCALL:
 433                         type = change_calling_convention(type, CC_THISCALL);
 434                         break;
 435                 case ATTRIBUTE_GNU_RETURNS_TWICE:
 436                 case ATTRIBUTE_MS_RETURNS_TWICE:
 437                         type = add_modifiers(type, DM_RETURNS_TWICE);
 438                         break;
 439                 case ATTRIBUTE_GNU_NORETURN:
 440                 case ATTRIBUTE_MS_NORETURN:
 441                         type = add_modifiers(type, DM_NORETURN);
 442                         break;
 443                 case ATTRIBUTE_GNU_MALLOC:
 444                 case ATTRIBUTE_MS_ALLOCATE:
 445                         type = add_modifiers(type, DM_MALLOC);
 446                         break;
 447                 case ATTRIBUTE_GNU_NOTHROW:
 448                 case ATTRIBUTE_MS_NOTHROW:
 449                         type = add_modifiers(type, DM_NOTHROW);
 450                         break;
 451                 case ATTRIBUTE_GNU_MODE:
 452                         type = handle_attribute_mode(attribute, type);
 453                         break;
 454                 default:
 455                         break;
 456                 }
 457         }
 458
 459         return type;
 460 }
 461
 462 const char *get_deprecated_string(const attribute_t *attribute)
 463 {
 464         for ( ; attribute != NULL; attribute = attribute->next) {
 465                 if (attribute->kind != ATTRIBUTE_MS_DEPRECATED)
 466                         continue;
 467
 468                 attribute_argument_t *argument = attribute->a.arguments;
 469                 return get_argument_string(argument);
 470         }
 471         return NULL;
 472 }
 473
 474 static bool property_attribute_equal(const attribute_property_argument_t *prop1,
 475                                      const attribute_property_argument_t *prop2)
 476 {
 477         return prop1->put_symbol == prop2->put_symbol
 478                 && prop1->get_symbol == prop2->get_symbol;
 479 }
 480
 481 static bool attribute_argument_equal(const attribute_argument_t *arg1,
 482                                      const attribute_argument_t *arg2)
 483 {
 484         if (arg1->kind != arg2->kind)
 485                 return false;
 486
 487         switch (arg1->kind) {
 488         case ATTRIBUTE_ARGUMENT_SYMBOL:
 489                 return arg1->v.symbol == arg2->v.symbol;
 490         case ATTRIBUTE_ARGUMENT_EXPRESSION:
 491                 /* TODO */
 492                 return false;
 493         }
 494         panic("unknown argument type");
 495 }
 496
 497 static bool attribute_arguments_equal(const attribute_argument_t *args1,
 498                                       const attribute_argument_t *args2)
 499 {
 500         for ( ; args1 != NULL && args2 != NULL;
 501              args1 = args1->next, args2 = args2->next) {
 502                 if (!attribute_argument_equal(args1, args2))
 503                         return false;
 504         }
 505         /* both should be NULL now */
 506         return args1 == args2;
 507 }
 508
 509 bool attributes_equal(const attribute_t *attr1, const attribute_t *attr2)
 510 {
 511         if (attr1->kind != attr2->kind)
 512                 return false;
 513
 514         switch (attr1->kind) {
 515         case ATTRIBUTE_MS_PROPERTY:
 516                 return property_attribute_equal(attr1->a.property, attr2->a.property);
 517         default:
 518                 return attribute_arguments_equal(attr1->a.arguments,
 519                                                  attr2->a.arguments);
 520         }
 521 }