gcc/c-common.c

   1 /* Subroutines shared by all languages that are variants of C.
   2    Copyright (C) 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000,
   3    2001, 2002, 2003, 2004 Free Software Foundation, Inc.
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify it under
   8 the terms of the GNU General Public License as published by the Free
   9 Software Foundation; either version 2, or (at your option) any later
  10 version.
  11
  12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15 for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GCC; see the file COPYING.  If not, write to the Free
  19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
  20 02111-1307, USA.  */
  21
  22 #include "config.h"
  23 #include "system.h"
  24 #include "coretypes.h"
  25 #include "tm.h"
  26 #include "intl.h"
  27 #include "tree.h"
  28 #include "flags.h"
  29 #include "output.h"
  30 #include "c-pragma.h"
  31 #include "rtl.h"
  32 #include "ggc.h"
  33 #include "varray.h"
  34 #include "expr.h"
  35 #include "c-common.h"
  36 #include "diagnostic.h"
  37 #include "tm_p.h"
  38 #include "obstack.h"
  39 #include "cpplib.h"
  40 #include "target.h"
  41 #include "langhooks.h"
  42 #include "tree-inline.h"
  43 #include "c-tree.h"
  44 #include "toplev.h"
  45 #include "tree-iterator.h"
  46 #include "hashtab.h"
  47 #include "tree-mudflap.h"
  48 #include "opts.h"
  49
  50 cpp_reader *parse_in;           /* Declared in c-pragma.h.  */
  51
  52 /* We let tm.h override the types used here, to handle trivial differences
  53    such as the choice of unsigned int or long unsigned int for size_t.
  54    When machines start needing nontrivial differences in the size type,
  55    it would be best to do something here to figure out automatically
  56    from other information what type to use.  */
  57
  58 #ifndef SIZE_TYPE
  59 #define SIZE_TYPE "long unsigned int"
  60 #endif
  61
  62 #ifndef PID_TYPE
  63 #define PID_TYPE "int"
  64 #endif
  65
  66 #ifndef WCHAR_TYPE
  67 #define WCHAR_TYPE "int"
  68 #endif
  69
  70 /* WCHAR_TYPE gets overridden by -fshort-wchar.  */
  71 #define MODIFIED_WCHAR_TYPE \
  72         (flag_short_wchar ? "short unsigned int" : WCHAR_TYPE)
  73
  74 #ifndef PTRDIFF_TYPE
  75 #define PTRDIFF_TYPE "long int"
  76 #endif
  77
  78 #ifndef WINT_TYPE
  79 #define WINT_TYPE "unsigned int"
  80 #endif
  81
  82 #ifndef INTMAX_TYPE
  83 #define INTMAX_TYPE ((INT_TYPE_SIZE == LONG_LONG_TYPE_SIZE)     \
  84                      ? "int"                                    \
  85                      : ((LONG_TYPE_SIZE == LONG_LONG_TYPE_SIZE) \
  86                         ? "long int"                            \
  87                         : "long long int"))
  88 #endif
  89
  90 #ifndef UINTMAX_TYPE
  91 #define UINTMAX_TYPE ((INT_TYPE_SIZE == LONG_LONG_TYPE_SIZE)    \
  92                      ? "unsigned int"                           \
  93                      : ((LONG_TYPE_SIZE == LONG_LONG_TYPE_SIZE) \
  94                         ? "long unsigned int"                   \
  95                         : "long long unsigned int"))
  96 #endif
  97
  98 /* The following symbols are subsumed in the c_global_trees array, and
  99    listed here individually for documentation purposes.
 100
 101    INTEGER_TYPE and REAL_TYPE nodes for the standard data types.
 102
 103         tree short_integer_type_node;
 104         tree long_integer_type_node;
 105         tree long_long_integer_type_node;
 106
 107         tree short_unsigned_type_node;
 108         tree long_unsigned_type_node;
 109         tree long_long_unsigned_type_node;
 110
 111         tree truthvalue_type_node;
 112         tree truthvalue_false_node;
 113         tree truthvalue_true_node;
 114
 115         tree ptrdiff_type_node;
 116
 117         tree unsigned_char_type_node;
 118         tree signed_char_type_node;
 119         tree wchar_type_node;
 120         tree signed_wchar_type_node;
 121         tree unsigned_wchar_type_node;
 122
 123         tree float_type_node;
 124         tree double_type_node;
 125         tree long_double_type_node;
 126
 127         tree complex_integer_type_node;
 128         tree complex_float_type_node;
 129         tree complex_double_type_node;
 130         tree complex_long_double_type_node;
 131
 132         tree intQI_type_node;
 133         tree intHI_type_node;
 134         tree intSI_type_node;
 135         tree intDI_type_node;
 136         tree intTI_type_node;
 137
 138         tree unsigned_intQI_type_node;
 139         tree unsigned_intHI_type_node;
 140         tree unsigned_intSI_type_node;
 141         tree unsigned_intDI_type_node;
 142         tree unsigned_intTI_type_node;
 143
 144         tree widest_integer_literal_type_node;
 145         tree widest_unsigned_literal_type_node;
 146
 147    Nodes for types `void *' and `const void *'.
 148
 149         tree ptr_type_node, const_ptr_type_node;
 150
 151    Nodes for types `char *' and `const char *'.
 152
 153         tree string_type_node, const_string_type_node;
 154
 155    Type `char[SOMENUMBER]'.
 156    Used when an array of char is needed and the size is irrelevant.
 157
 158         tree char_array_type_node;
 159
 160    Type `int[SOMENUMBER]' or something like it.
 161    Used when an array of int needed and the size is irrelevant.
 162
 163         tree int_array_type_node;
 164
 165    Type `wchar_t[SOMENUMBER]' or something like it.
 166    Used when a wide string literal is created.
 167
 168         tree wchar_array_type_node;
 169
 170    Type `int ()' -- used for implicit declaration of functions.
 171
 172         tree default_function_type;
 173
 174    A VOID_TYPE node, packaged in a TREE_LIST.
 175
 176         tree void_list_node;
 177
 178   The lazily created VAR_DECLs for __FUNCTION__, __PRETTY_FUNCTION__,
 179   and __func__. (C doesn't generate __FUNCTION__ and__PRETTY_FUNCTION__
 180   VAR_DECLS, but C++ does.)
 181
 182         tree function_name_decl_node;
 183         tree pretty_function_name_decl_node;
 184         tree c99_function_name_decl_node;
 185
 186   Stack of nested function name VAR_DECLs.
 187
 188         tree saved_function_name_decls;
 189
 190 */
 191
 192 tree c_global_trees[CTI_MAX];
 193
 194 /* TRUE if a code represents a statement.  The front end init
 195    langhook should take care of initialization of this array.  */
 196
 197 bool statement_code_p[MAX_TREE_CODES];
 198 \f
 199 /* Switches common to the C front ends.  */
 200
 201 /* Nonzero if prepreprocessing only.  */
 202
 203 int flag_preprocess_only;
 204
 205 /* Nonzero means don't output line number information.  */
 206
 207 char flag_no_line_commands;
 208
 209 /* Nonzero causes -E output not to be done, but directives such as
 210    #define that have side effects are still obeyed.  */
 211
 212 char flag_no_output;
 213
 214 /* Nonzero means dump macros in some fashion.  */
 215
 216 char flag_dump_macros;
 217
 218 /* Nonzero means pass #include lines through to the output.  */
 219
 220 char flag_dump_includes;
 221
 222 /* Nonzero means process PCH files while preprocessing.  */
 223
 224 bool flag_pch_preprocess;
 225
 226 /* The file name to which we should write a precompiled header, or
 227    NULL if no header will be written in this compile.  */
 228
 229 const char *pch_file;
 230
 231 /* Nonzero if an ISO standard was selected.  It rejects macros in the
 232    user's namespace.  */
 233 int flag_iso;
 234
 235 /* Nonzero if -undef was given.  It suppresses target built-in macros
 236    and assertions.  */
 237 int flag_undef;
 238
 239 /* Nonzero means don't recognize the non-ANSI builtin functions.  */
 240
 241 int flag_no_builtin;
 242
 243 /* Nonzero means don't recognize the non-ANSI builtin functions.
 244    -ansi sets this.  */
 245
 246 int flag_no_nonansi_builtin;
 247
 248 /* Nonzero means give `double' the same size as `float'.  */
 249
 250 int flag_short_double;
 251
 252 /* Nonzero means give `wchar_t' the same size as `short'.  */
 253
 254 int flag_short_wchar;
 255
 256 /* Nonzero means allow Microsoft extensions without warnings or errors.  */
 257 int flag_ms_extensions;
 258
 259 /* Nonzero means don't recognize the keyword `asm'.  */
 260
 261 int flag_no_asm;
 262
 263 /* Nonzero means give string constants the type `const char *', as mandated
 264    by the standard.  */
 265
 266 int flag_const_strings;
 267
 268 /* Nonzero means to treat bitfields as signed unless they say `unsigned'.  */
 269
 270 int flag_signed_bitfields = 1;
 271 int explicit_flag_signed_bitfields;
 272
 273 /* Nonzero means warn about deprecated conversion from string constant to
 274    `char *'.  */
 275
 276 int warn_write_strings;
 277
 278 /* Warn about #pragma directives that are not recognized.  */
 279
 280 int warn_unknown_pragmas; /* Tri state variable.  */
 281
 282 /* Warn about format/argument anomalies in calls to formatted I/O functions
 283    (*printf, *scanf, strftime, strfmon, etc.).  */
 284
 285 int warn_format;
 286
 287 /* Zero means that faster, ...NonNil variants of objc_msgSend...
 288    calls will be used in ObjC; passing nil receivers to such calls
 289    will most likely result in crashes.  */
 290 int flag_nil_receivers = 1;
 291
 292 /* Nonzero means that we will allow new ObjC exception syntax (@throw,
 293    @try, etc.) in source code.  */
 294 int flag_objc_exceptions = 0;
 295
 296 /* Nonzero means that we generate NeXT setjmp based exceptions.  */
 297 int flag_objc_sjlj_exceptions = -1;
 298
 299 /* Nonzero means that code generation will be altered to support
 300    "zero-link" execution.  This currently affects ObjC only, but may
 301    affect other languages in the future.  */
 302 int flag_zero_link = 0;
 303
 304 /* Nonzero means emit an '__OBJC, __image_info' for the current translation
 305    unit.  It will inform the ObjC runtime that class definition(s) herein
 306    contained are to replace one(s) previously loaded.  */
 307 int flag_replace_objc_classes = 0;
 308
 309 /* C/ObjC language option variables.  */
 310
 311
 312 /* Nonzero means allow type mismatches in conditional expressions;
 313    just make their values `void'.  */
 314
 315 int flag_cond_mismatch;
 316
 317 /* Nonzero means enable C89 Amendment 1 features.  */
 318
 319 int flag_isoc94;
 320
 321 /* Nonzero means use the ISO C99 dialect of C.  */
 322
 323 int flag_isoc99;
 324
 325 /* Nonzero means that we have builtin functions, and main is an int.  */
 326
 327 int flag_hosted = 1;
 328
 329 /* Warn if main is suspicious.  */
 330
 331 int warn_main;
 332
 333
 334 /* ObjC language option variables.  */
 335
 336
 337 /* Open and close the file for outputting class declarations, if
 338    requested (ObjC).  */
 339
 340 int flag_gen_declaration;
 341
 342 /* Generate code for GNU or NeXT runtime environment.  */
 343
 344 #ifdef NEXT_OBJC_RUNTIME
 345 int flag_next_runtime = 1;
 346 #else
 347 int flag_next_runtime = 0;
 348 #endif
 349
 350 /* Tells the compiler that this is a special run.  Do not perform any
 351    compiling, instead we are to test some platform dependent features
 352    and output a C header file with appropriate definitions.  */
 353
 354 int print_struct_values;
 355
 356 /* ???.  Undocumented.  */
 357
 358 const char *constant_string_class_name;
 359
 360
 361 /* C++ language option variables.  */
 362
 363
 364 /* Nonzero means don't recognize any extension keywords.  */
 365
 366 int flag_no_gnu_keywords;
 367
 368 /* Nonzero means do emit exported implementations of functions even if
 369    they can be inlined.  */
 370
 371 int flag_implement_inlines = 1;
 372
 373 /* Nonzero means that implicit instantiations will be emitted if needed.  */
 374
 375 int flag_implicit_templates = 1;
 376
 377 /* Nonzero means that implicit instantiations of inline templates will be
 378    emitted if needed, even if instantiations of non-inline templates
 379    aren't.  */
 380
 381 int flag_implicit_inline_templates = 1;
 382
 383 /* Nonzero means generate separate instantiation control files and
 384    juggle them at link time.  */
 385
 386 int flag_use_repository;
 387
 388 /* Nonzero if we want to issue diagnostics that the standard says are not
 389    required.  */
 390
 391 int flag_optional_diags = 1;
 392
 393 /* Nonzero means we should attempt to elide constructors when possible.  */
 394
 395 int flag_elide_constructors = 1;
 396
 397 /* Nonzero means that member functions defined in class scope are
 398    inline by default.  */
 399
 400 int flag_default_inline = 1;
 401
 402 /* Controls whether compiler generates 'type descriptor' that give
 403    run-time type information.  */
 404
 405 int flag_rtti = 1;
 406
 407 /* Nonzero if we want to conserve space in the .o files.  We do this
 408    by putting uninitialized data and runtime initialized data into
 409    .common instead of .data at the expense of not flagging multiple
 410    definitions.  */
 411
 412 int flag_conserve_space;
 413
 414 /* Nonzero if we want to obey access control semantics.  */
 415
 416 int flag_access_control = 1;
 417
 418 /* Nonzero if we want to check the return value of new and avoid calling
 419    constructors if it is a null pointer.  */
 420
 421 int flag_check_new;
 422
 423 /* Nonzero if we want the new ISO rules for pushing a new scope for `for'
 424    initialization variables.
 425    0: Old rules, set by -fno-for-scope.
 426    2: New ISO rules, set by -ffor-scope.
 427    1: Try to implement new ISO rules, but with backup compatibility
 428    (and warnings).  This is the default, for now.  */
 429
 430 int flag_new_for_scope = 1;
 431
 432 /* Nonzero if we want to emit defined symbols with common-like linkage as
 433    weak symbols where possible, in order to conform to C++ semantics.
 434    Otherwise, emit them as local symbols.  */
 435
 436 int flag_weak = 1;
 437
 438 /* 0 means we want the preprocessor to not emit line directives for
 439    the current working directory.  1 means we want it to do it.  -1
 440    means we should decide depending on whether debugging information
 441    is being emitted or not.  */
 442
 443 int flag_working_directory = -1;
 444
 445 /* Nonzero to use __cxa_atexit, rather than atexit, to register
 446    destructors for local statics and global objects.  */
 447
 448 int flag_use_cxa_atexit = DEFAULT_USE_CXA_ATEXIT;
 449
 450 /* Nonzero means make the default pedwarns warnings instead of errors.
 451    The value of this flag is ignored if -pedantic is specified.  */
 452
 453 int flag_permissive;
 454
 455 /* Nonzero means to implement standard semantics for exception
 456    specifications, calling unexpected if an exception is thrown that
 457    doesn't match the specification.  Zero means to treat them as
 458    assertions and optimize accordingly, but not check them.  */
 459
 460 int flag_enforce_eh_specs = 1;
 461
 462 /* Nonzero means to generate thread-safe code for initializing local
 463    statics.  */
 464
 465 int flag_threadsafe_statics = 1;
 466
 467 /* Nonzero means warn about implicit declarations.  */
 468
 469 int warn_implicit = 1;
 470
 471 /* Maximum template instantiation depth.  This limit is rather
 472    arbitrary, but it exists to limit the time it takes to notice
 473    infinite template instantiations.  */
 474
 475 int max_tinst_depth = 500;
 476
 477
 478
 479 /* The elements of `ridpointers' are identifier nodes for the reserved
 480    type names and storage classes.  It is indexed by a RID_... value.  */
 481 tree *ridpointers;
 482
 483 tree (*make_fname_decl) (tree, int);
 484
 485 /* If non-NULL, the address of a language-specific function that
 486    returns 1 for language-specific statement codes.  */
 487 int (*lang_statement_code_p) (enum tree_code);
 488
 489 /* If non-NULL, the address of a language-specific function that takes
 490    any action required right before expand_function_end is called.  */
 491 void (*lang_expand_function_end) (void);
 492
 493 /* Nonzero means the expression being parsed will never be evaluated.
 494    This is a count, since unevaluated expressions can nest.  */
 495 int skip_evaluation;
 496
 497 /* Information about how a function name is generated.  */
 498 struct fname_var_t
 499 {
 500   tree *const decl;     /* pointer to the VAR_DECL.  */
 501   const unsigned rid;   /* RID number for the identifier.  */
 502   const int pretty;     /* How pretty is it? */
 503 };
 504
 505 /* The three ways of getting then name of the current function.  */
 506
 507 const struct fname_var_t fname_vars[] =
 508 {
 509   /* C99 compliant __func__, must be first.  */
 510   {&c99_function_name_decl_node, RID_C99_FUNCTION_NAME, 0},
 511   /* GCC __FUNCTION__ compliant.  */
 512   {&function_name_decl_node, RID_FUNCTION_NAME, 0},
 513   /* GCC __PRETTY_FUNCTION__ compliant.  */
 514   {&pretty_function_name_decl_node, RID_PRETTY_FUNCTION_NAME, 1},
 515   {NULL, 0, 0},
 516 };
 517
 518 static int constant_fits_type_p (tree, tree);
 519 static tree check_case_value (tree);
 520 static bool check_case_bounds (tree, tree, tree *, tree *);
 521
 522 static tree handle_packed_attribute (tree *, tree, tree, int, bool *);
 523 static tree handle_nocommon_attribute (tree *, tree, tree, int, bool *);
 524 static tree handle_common_attribute (tree *, tree, tree, int, bool *);
 525 static tree handle_noreturn_attribute (tree *, tree, tree, int, bool *);
 526 static tree handle_noinline_attribute (tree *, tree, tree, int, bool *);
 527 static tree handle_always_inline_attribute (tree *, tree, tree, int,
 528                                             bool *);
 529 static tree handle_used_attribute (tree *, tree, tree, int, bool *);
 530 static tree handle_unused_attribute (tree *, tree, tree, int, bool *);
 531 static tree handle_const_attribute (tree *, tree, tree, int, bool *);
 532 static tree handle_transparent_union_attribute (tree *, tree, tree,
 533                                                 int, bool *);
 534 static tree handle_constructor_attribute (tree *, tree, tree, int, bool *);
 535 static tree handle_destructor_attribute (tree *, tree, tree, int, bool *);
 536 static tree handle_mode_attribute (tree *, tree, tree, int, bool *);
 537 static tree handle_section_attribute (tree *, tree, tree, int, bool *);
 538 static tree handle_aligned_attribute (tree *, tree, tree, int, bool *);
 539 static tree handle_weak_attribute (tree *, tree, tree, int, bool *) ;
 540 static tree handle_alias_attribute (tree *, tree, tree, int, bool *);
 541 static tree handle_visibility_attribute (tree *, tree, tree, int,
 542                                          bool *);
 543 static tree handle_tls_model_attribute (tree *, tree, tree, int,
 544                                         bool *);
 545 static tree handle_no_instrument_function_attribute (tree *, tree,
 546                                                      tree, int, bool *);
 547 static tree handle_malloc_attribute (tree *, tree, tree, int, bool *);
 548 static tree handle_no_limit_stack_attribute (tree *, tree, tree, int,
 549                                              bool *);
 550 static tree handle_pure_attribute (tree *, tree, tree, int, bool *);
 551 static tree handle_deprecated_attribute (tree *, tree, tree, int,
 552                                          bool *);
 553 static tree handle_vector_size_attribute (tree *, tree, tree, int,
 554                                           bool *);
 555 static tree handle_nonnull_attribute (tree *, tree, tree, int, bool *);
 556 static tree handle_nothrow_attribute (tree *, tree, tree, int, bool *);
 557 static tree handle_cleanup_attribute (tree *, tree, tree, int, bool *);
 558 static tree handle_warn_unused_result_attribute (tree *, tree, tree, int,
 559                                                  bool *);
 560 static tree handle_sentinel_attribute (tree *, tree, tree, int, bool *);
 561
 562 static void check_function_nonnull (tree, tree);
 563 static void check_nonnull_arg (void *, tree, unsigned HOST_WIDE_INT);
 564 static bool nonnull_check_p (tree, unsigned HOST_WIDE_INT);
 565 static bool get_nonnull_operand (tree, unsigned HOST_WIDE_INT *);
 566 static int resort_field_decl_cmp (const void *, const void *);
 567
 568 /* Table of machine-independent attributes common to all C-like languages.  */
 569 const struct attribute_spec c_common_attribute_table[] =
 570 {
 571   /* { name, min_len, max_len, decl_req, type_req, fn_type_req, handler } */
 572   { "packed",                 0, 0, false, false, false,
 573                               handle_packed_attribute },
 574   { "nocommon",               0, 0, true,  false, false,
 575                               handle_nocommon_attribute },
 576   { "common",                 0, 0, true,  false, false,
 577                               handle_common_attribute },
 578   /* FIXME: logically, noreturn attributes should be listed as
 579      "false, true, true" and apply to function types.  But implementing this
 580      would require all the places in the compiler that use TREE_THIS_VOLATILE
 581      on a decl to identify non-returning functions to be located and fixed
 582      to check the function type instead.  */
 583   { "noreturn",               0, 0, true,  false, false,
 584                               handle_noreturn_attribute },
 585   { "volatile",               0, 0, true,  false, false,
 586                               handle_noreturn_attribute },
 587   { "noinline",               0, 0, true,  false, false,
 588                               handle_noinline_attribute },
 589   { "always_inline",          0, 0, true,  false, false,
 590                               handle_always_inline_attribute },
 591   { "used",                   0, 0, true,  false, false,
 592                               handle_used_attribute },
 593   { "unused",                 0, 0, false, false, false,
 594                               handle_unused_attribute },
 595   /* The same comments as for noreturn attributes apply to const ones.  */
 596   { "const",                  0, 0, true,  false, false,
 597                               handle_const_attribute },
 598   { "transparent_union",      0, 0, false, false, false,
 599                               handle_transparent_union_attribute },
 600   { "constructor",            0, 0, true,  false, false,
 601                               handle_constructor_attribute },
 602   { "destructor",             0, 0, true,  false, false,
 603                               handle_destructor_attribute },
 604   { "mode",                   1, 1, false,  true, false,
 605                               handle_mode_attribute },
 606   { "section",                1, 1, true,  false, false,
 607                               handle_section_attribute },
 608   { "aligned",                0, 1, false, false, false,
 609                               handle_aligned_attribute },
 610   { "weak",                   0, 0, true,  false, false,
 611                               handle_weak_attribute },
 612   { "alias",                  1, 1, true,  false, false,
 613                               handle_alias_attribute },
 614   { "no_instrument_function", 0, 0, true,  false, false,
 615                               handle_no_instrument_function_attribute },
 616   { "malloc",                 0, 0, true,  false, false,
 617                               handle_malloc_attribute },
 618   { "no_stack_limit",         0, 0, true,  false, false,
 619                               handle_no_limit_stack_attribute },
 620   { "pure",                   0, 0, true,  false, false,
 621                               handle_pure_attribute },
 622   { "deprecated",             0, 0, false, false, false,
 623                               handle_deprecated_attribute },
 624   { "vector_size",            1, 1, false, true, false,
 625                               handle_vector_size_attribute },
 626   { "visibility",             1, 1, false, false, false,
 627                               handle_visibility_attribute },
 628   { "tls_model",              1, 1, true,  false, false,
 629                               handle_tls_model_attribute },
 630   { "nonnull",                0, -1, false, true, true,
 631                               handle_nonnull_attribute },
 632   { "nothrow",                0, 0, true,  false, false,
 633                               handle_nothrow_attribute },
 634   { "may_alias",              0, 0, false, true, false, NULL },
 635   { "cleanup",                1, 1, true, false, false,
 636                               handle_cleanup_attribute },
 637   { "warn_unused_result",     0, 0, false, true, true,
 638                               handle_warn_unused_result_attribute },
 639   { "sentinel",               0, 1, false, true, true,
 640                               handle_sentinel_attribute },
 641   { NULL,                     0, 0, false, false, false, NULL }
 642 };
 643
 644 /* Give the specifications for the format attributes, used by C and all
 645    descendants.  */
 646
 647 const struct attribute_spec c_common_format_attribute_table[] =
 648 {
 649   /* { name, min_len, max_len, decl_req, type_req, fn_type_req, handler } */
 650   { "format",                 3, 3, false, true,  true,
 651                               handle_format_attribute },
 652   { "format_arg",             1, 1, false, true,  true,
 653                               handle_format_arg_attribute },
 654   { NULL,                     0, 0, false, false, false, NULL }
 655 };
 656
 657 /* Push current bindings for the function name VAR_DECLS.  */
 658
 659 void
 660 start_fname_decls (void)
 661 {
 662   unsigned ix;
 663   tree saved = NULL_TREE;
 664
 665   for (ix = 0; fname_vars[ix].decl; ix++)
 666     {
 667       tree decl = *fname_vars[ix].decl;
 668
 669       if (decl)
 670         {
 671           saved = tree_cons (decl, build_int_cst (NULL_TREE, ix), saved);
 672           *fname_vars[ix].decl = NULL_TREE;
 673         }
 674     }
 675   if (saved || saved_function_name_decls)
 676     /* Normally they'll have been NULL, so only push if we've got a
 677        stack, or they are non-NULL.  */
 678     saved_function_name_decls = tree_cons (saved, NULL_TREE,
 679                                            saved_function_name_decls);
 680 }
 681
 682 /* Finish up the current bindings, adding them into the current function's
 683    statement tree.  This must be done _before_ finish_stmt_tree is called.
 684    If there is no current function, we must be at file scope and no statements
 685    are involved. Pop the previous bindings.  */
 686
 687 void
 688 finish_fname_decls (void)
 689 {
 690   unsigned ix;
 691   tree stmts = NULL_TREE;
 692   tree stack = saved_function_name_decls;
 693
 694   for (; stack && TREE_VALUE (stack); stack = TREE_CHAIN (stack))
 695     append_to_statement_list (TREE_VALUE (stack), &stmts);
 696
 697   if (stmts)
 698     {
 699       tree *bodyp = &DECL_SAVED_TREE (current_function_decl);
 700
 701       if (TREE_CODE (*bodyp) == BIND_EXPR)
 702         bodyp = &BIND_EXPR_BODY (*bodyp);
 703
 704       append_to_statement_list (*bodyp, &stmts);
 705       *bodyp = stmts;
 706     }
 707
 708   for (ix = 0; fname_vars[ix].decl; ix++)
 709     *fname_vars[ix].decl = NULL_TREE;
 710
 711   if (stack)
 712     {
 713       /* We had saved values, restore them.  */
 714       tree saved;
 715
 716       for (saved = TREE_PURPOSE (stack); saved; saved = TREE_CHAIN (saved))
 717         {
 718           tree decl = TREE_PURPOSE (saved);
 719           unsigned ix = TREE_INT_CST_LOW (TREE_VALUE (saved));
 720
 721           *fname_vars[ix].decl = decl;
 722         }
 723       stack = TREE_CHAIN (stack);
 724     }
 725   saved_function_name_decls = stack;
 726 }
 727
 728 /* Return the text name of the current function, suitably prettified
 729    by PRETTY_P.  Return string must be freed by caller.  */
 730
 731 const char *
 732 fname_as_string (int pretty_p)
 733 {
 734   const char *name = "top level";
 735   char *namep;
 736   int vrb = 2;
 737
 738   if (! pretty_p)
 739     {
 740       name = "";
 741       vrb = 0;
 742     }
 743
 744   if (current_function_decl)
 745     name = lang_hooks.decl_printable_name (current_function_decl, vrb);
 746
 747   if (c_lex_string_translate)
 748     {
 749       int len = strlen (name) + 3; /* Two for '"'s.  One for NULL.  */
 750       cpp_string cstr = { 0, 0 }, strname;
 751
 752       namep = XNEWVEC (char, len);
 753       snprintf (namep, len, "\"%s\"", name);
 754       strname.text = (unsigned char *) namep;
 755       strname.len = len - 1;
 756
 757       if (cpp_interpret_string (parse_in, &strname, 1, &cstr, false))
 758         return (char *) cstr.text;
 759     }
 760   else
 761     namep = xstrdup (name);
 762
 763   return namep;
 764 }
 765
 766 /* Expand DECL if it declares an entity not handled by the
 767    common code.  */
 768
 769 int
 770 c_expand_decl (tree decl)
 771 {
 772   if (TREE_CODE (decl) == VAR_DECL && !TREE_STATIC (decl))
 773     {
 774       /* Let the back-end know about this variable.  */
 775       if (!anon_aggr_type_p (TREE_TYPE (decl)))
 776         emit_local_var (decl);
 777       else
 778         expand_anon_union_decl (decl, NULL_TREE,
 779                                 DECL_ANON_UNION_ELEMS (decl));
 780     }
 781   else
 782     return 0;
 783
 784   return 1;
 785 }
 786
 787
 788 /* Return the VAR_DECL for a const char array naming the current
 789    function. If the VAR_DECL has not yet been created, create it
 790    now. RID indicates how it should be formatted and IDENTIFIER_NODE
 791    ID is its name (unfortunately C and C++ hold the RID values of
 792    keywords in different places, so we can't derive RID from ID in
 793    this language independent code.  */
 794
 795 tree
 796 fname_decl (unsigned int rid, tree id)
 797 {
 798   unsigned ix;
 799   tree decl = NULL_TREE;
 800
 801   for (ix = 0; fname_vars[ix].decl; ix++)
 802     if (fname_vars[ix].rid == rid)
 803       break;
 804
 805   decl = *fname_vars[ix].decl;
 806   if (!decl)
 807     {
 808       /* If a tree is built here, it would normally have the lineno of
 809          the current statement.  Later this tree will be moved to the
 810          beginning of the function and this line number will be wrong.
 811          To avoid this problem set the lineno to 0 here; that prevents
 812          it from appearing in the RTL.  */
 813       tree stmts;
 814       location_t saved_location = input_location;
 815 #ifdef USE_MAPPED_LOCATION
 816       input_location = UNKNOWN_LOCATION;
 817 #else
 818       input_line = 0;
 819 #endif
 820
 821       stmts = push_stmt_list ();
 822       decl = (*make_fname_decl) (id, fname_vars[ix].pretty);
 823       stmts = pop_stmt_list (stmts);
 824       if (!IS_EMPTY_STMT (stmts))
 825         saved_function_name_decls
 826           = tree_cons (decl, stmts, saved_function_name_decls);
 827       *fname_vars[ix].decl = decl;
 828       input_location = saved_location;
 829     }
 830   if (!ix && !current_function_decl)
 831     pedwarn ("%J%qD is not defined outside of function scope", decl, decl);
 832
 833   return decl;
 834 }
 835
 836 /* Given a STRING_CST, give it a suitable array-of-chars data type.  */
 837
 838 tree
 839 fix_string_type (tree value)
 840 {
 841   const int wchar_bytes = TYPE_PRECISION (wchar_type_node) / BITS_PER_UNIT;
 842   const int wide_flag = TREE_TYPE (value) == wchar_array_type_node;
 843   const int nchars_max = flag_isoc99 ? 4095 : 509;
 844   int length = TREE_STRING_LENGTH (value);
 845   int nchars;
 846   tree e_type, i_type, a_type;
 847
 848   /* Compute the number of elements, for the array type.  */
 849   nchars = wide_flag ? length / wchar_bytes : length;
 850
 851   if (pedantic && nchars - 1 > nchars_max && !c_dialect_cxx ())
 852     pedwarn ("string length %qd is greater than the length %qd ISO C%d compilers are required to support",
 853              nchars - 1, nchars_max, flag_isoc99 ? 99 : 89);
 854
 855   e_type = wide_flag ? wchar_type_node : char_type_node;
 856   /* Create the array type for the string constant.  flag_const_strings
 857      says make the string constant an array of const char so that
 858      copying it to a non-const pointer will get a warning.  For C++,
 859      this is the standard behavior.
 860
 861      The C++ front end relies on TYPE_MAIN_VARIANT of a cv-qualified
 862      array type being the unqualified version of that type.
 863      Therefore, if we are constructing an array of const char, we must
 864      construct the matching unqualified array type first.  The C front
 865      end does not require this, but it does no harm, so we do it
 866      unconditionally.  */
 867   i_type = build_index_type (build_int_cst (NULL_TREE, nchars - 1));
 868   a_type = build_array_type (e_type, i_type);
 869   if (flag_const_strings)
 870     {
 871       /* bleah, c_build_qualified_type should set TYPE_MAIN_VARIANT.  */
 872       tree qa_type = c_build_qualified_type (a_type, TYPE_QUAL_CONST);
 873       TYPE_MAIN_VARIANT (qa_type) = a_type;
 874       a_type = qa_type;
 875     }
 876
 877   TREE_TYPE (value) = a_type;
 878   TREE_CONSTANT (value) = 1;
 879   TREE_INVARIANT (value) = 1;
 880   TREE_READONLY (value) = 1;
 881   TREE_STATIC (value) = 1;
 882   return value;
 883 }
 884 \f
 885 /* Print a warning if a constant expression had overflow in folding.
 886    Invoke this function on every expression that the language
 887    requires to be a constant expression.
 888    Note the ANSI C standard says it is erroneous for a
 889    constant expression to overflow.  */
 890
 891 void
 892 constant_expression_warning (tree value)
 893 {
 894   if ((TREE_CODE (value) == INTEGER_CST || TREE_CODE (value) == REAL_CST
 895        || TREE_CODE (value) == VECTOR_CST
 896        || TREE_CODE (value) == COMPLEX_CST)
 897       && TREE_CONSTANT_OVERFLOW (value) && pedantic)
 898     pedwarn ("overflow in constant expression");
 899 }
 900
 901 /* Print a warning if an expression had overflow in folding.
 902    Invoke this function on every expression that
 903    (1) appears in the source code, and
 904    (2) might be a constant expression that overflowed, and
 905    (3) is not already checked by convert_and_check;
 906    however, do not invoke this function on operands of explicit casts.  */
 907
 908 void
 909 overflow_warning (tree value)
 910 {
 911   if ((TREE_CODE (value) == INTEGER_CST
 912        || (TREE_CODE (value) == COMPLEX_CST
 913            && TREE_CODE (TREE_REALPART (value)) == INTEGER_CST))
 914       && TREE_OVERFLOW (value))
 915     {
 916       TREE_OVERFLOW (value) = 0;
 917       if (skip_evaluation == 0)
 918         warning ("integer overflow in expression");
 919     }
 920   else if ((TREE_CODE (value) == REAL_CST
 921             || (TREE_CODE (value) == COMPLEX_CST
 922                 && TREE_CODE (TREE_REALPART (value)) == REAL_CST))
 923            && TREE_OVERFLOW (value))
 924     {
 925       TREE_OVERFLOW (value) = 0;
 926       if (skip_evaluation == 0)
 927         warning ("floating point overflow in expression");
 928     }
 929   else if (TREE_CODE (value) == VECTOR_CST && TREE_OVERFLOW (value))
 930     {
 931       TREE_OVERFLOW (value) = 0;
 932       if (skip_evaluation == 0)
 933         warning ("vector overflow in expression");
 934     }
 935 }
 936
 937 /* Print a warning if a large constant is truncated to unsigned,
 938    or if -Wconversion is used and a constant < 0 is converted to unsigned.
 939    Invoke this function on every expression that might be implicitly
 940    converted to an unsigned type.  */
 941
 942 void
 943 unsigned_conversion_warning (tree result, tree operand)
 944 {
 945   tree type = TREE_TYPE (result);
 946
 947   if (TREE_CODE (operand) == INTEGER_CST
 948       && TREE_CODE (type) == INTEGER_TYPE
 949       && TYPE_UNSIGNED (type)
 950       && skip_evaluation == 0
 951       && !int_fits_type_p (operand, type))
 952     {
 953       if (!int_fits_type_p (operand, c_common_signed_type (type)))
 954         /* This detects cases like converting -129 or 256 to unsigned char.  */
 955         warning ("large integer implicitly truncated to unsigned type");
 956       else if (warn_conversion)
 957         warning ("negative integer implicitly converted to unsigned type");
 958     }
 959 }
 960
 961 /* Nonzero if constant C has a value that is permissible
 962    for type TYPE (an INTEGER_TYPE).  */
 963
 964 static int
 965 constant_fits_type_p (tree c, tree type)
 966 {
 967   if (TREE_CODE (c) == INTEGER_CST)
 968     return int_fits_type_p (c, type);
 969
 970   c = convert (type, c);
 971   return !TREE_OVERFLOW (c);
 972 }
 973
 974 /* Nonzero if vector types T1 and T2 can be converted to each other
 975    without an explicit cast.  */
 976 int
 977 vector_types_convertible_p (tree t1, tree t2)
 978 {
 979   return targetm.vector_opaque_p (t1)
 980          || targetm.vector_opaque_p (t2)
 981          || (tree_int_cst_equal (TYPE_SIZE (t1), TYPE_SIZE (t2))
 982              && INTEGRAL_TYPE_P (TREE_TYPE (t1))
 983                 == INTEGRAL_TYPE_P (TREE_TYPE (t2)));
 984 }
 985
 986 /* Convert EXPR to TYPE, warning about conversion problems with constants.
 987    Invoke this function on every expression that is converted implicitly,
 988    i.e. because of language rules and not because of an explicit cast.  */
 989
 990 tree
 991 convert_and_check (tree type, tree expr)
 992 {
 993   tree t = convert (type, expr);
 994   if (TREE_CODE (t) == INTEGER_CST)
 995     {
 996       if (TREE_OVERFLOW (t))
 997         {
 998           TREE_OVERFLOW (t) = 0;
 999
1000           /* Do not diagnose overflow in a constant expression merely
1001              because a conversion overflowed.  */
1002           TREE_CONSTANT_OVERFLOW (t) = TREE_CONSTANT_OVERFLOW (expr);
1003
1004           /* No warning for converting 0x80000000 to int.  */
1005           if (!(TYPE_UNSIGNED (type) < TYPE_UNSIGNED (TREE_TYPE (expr))
1006                 && TREE_CODE (TREE_TYPE (expr)) == INTEGER_TYPE
1007                 && TYPE_PRECISION (type) == TYPE_PRECISION (TREE_TYPE (expr))))
1008             /* If EXPR fits in the unsigned version of TYPE,
1009                don't warn unless pedantic.  */
1010             if ((pedantic
1011                  || TYPE_UNSIGNED (type)
1012                  || ! constant_fits_type_p (expr,
1013                                             c_common_unsigned_type (type)))
1014                 && skip_evaluation == 0)
1015               warning ("overflow in implicit constant conversion");
1016         }
1017       else
1018         unsigned_conversion_warning (t, expr);
1019     }
1020   return t;
1021 }
1022 \f
1023 /* A node in a list that describes references to variables (EXPR), which are
1024    either read accesses if WRITER is zero, or write accesses, in which case
1025    WRITER is the parent of EXPR.  */
1026 struct tlist
1027 {
1028   struct tlist *next;
1029   tree expr, writer;
1030 };
1031
1032 /* Used to implement a cache the results of a call to verify_tree.  We only
1033    use this for SAVE_EXPRs.  */
1034 struct tlist_cache
1035 {
1036   struct tlist_cache *next;
1037   struct tlist *cache_before_sp;
1038   struct tlist *cache_after_sp;
1039   tree expr;
1040 };
1041
1042 /* Obstack to use when allocating tlist structures, and corresponding
1043    firstobj.  */
1044 static struct obstack tlist_obstack;
1045 static char *tlist_firstobj = 0;
1046
1047 /* Keep track of the identifiers we've warned about, so we can avoid duplicate
1048    warnings.  */
1049 static struct tlist *warned_ids;
1050 /* SAVE_EXPRs need special treatment.  We process them only once and then
1051    cache the results.  */
1052 static struct tlist_cache *save_expr_cache;
1053
1054 static void add_tlist (struct tlist **, struct tlist *, tree, int);
1055 static void merge_tlist (struct tlist **, struct tlist *, int);
1056 static void verify_tree (tree, struct tlist **, struct tlist **, tree);
1057 static int warning_candidate_p (tree);
1058 static void warn_for_collisions (struct tlist *);
1059 static void warn_for_collisions_1 (tree, tree, struct tlist *, int);
1060 static struct tlist *new_tlist (struct tlist *, tree, tree);
1061
1062 /* Create a new struct tlist and fill in its fields.  */
1063 static struct tlist *
1064 new_tlist (struct tlist *next, tree t, tree writer)
1065 {
1066   struct tlist *l;
1067   l = XOBNEW (&tlist_obstack, struct tlist);
1068   l->next = next;
1069   l->expr = t;
1070   l->writer = writer;
1071   return l;
1072 }
1073
1074 /* Add duplicates of the nodes found in ADD to the list *TO.  If EXCLUDE_WRITER
1075    is nonnull, we ignore any node we find which has a writer equal to it.  */
1076
1077 static void
1078 add_tlist (struct tlist **to, struct tlist *add, tree exclude_writer, int copy)
1079 {
1080   while (add)
1081     {
1082       struct tlist *next = add->next;
1083       if (! copy)
1084         add->next = *to;
1085       if (! exclude_writer || add->writer != exclude_writer)
1086         *to = copy ? new_tlist (*to, add->expr, add->writer) : add;
1087       add = next;
1088     }
1089 }
1090
1091 /* Merge the nodes of ADD into TO.  This merging process is done so that for
1092    each variable that already exists in TO, no new node is added; however if
1093    there is a write access recorded in ADD, and an occurrence on TO is only
1094    a read access, then the occurrence in TO will be modified to record the
1095    write.  */
1096
1097 static void
1098 merge_tlist (struct tlist **to, struct tlist *add, int copy)
1099 {
1100   struct tlist **end = to;
1101
1102   while (*end)
1103     end = &(*end)->next;
1104
1105   while (add)
1106     {
1107       int found = 0;
1108       struct tlist *tmp2;
1109       struct tlist *next = add->next;
1110
1111       for (tmp2 = *to; tmp2; tmp2 = tmp2->next)
1112         if (tmp2->expr == add->expr)
1113           {
1114             found = 1;
1115             if (! tmp2->writer)
1116               tmp2->writer = add->writer;
1117           }
1118       if (! found)
1119         {
1120           *end = copy ? add : new_tlist (NULL, add->expr, add->writer);
1121           end = &(*end)->next;
1122           *end = 0;
1123         }
1124       add = next;
1125     }
1126 }
1127
1128 /* WRITTEN is a variable, WRITER is its parent.  Warn if any of the variable
1129    references in list LIST conflict with it, excluding reads if ONLY writers
1130    is nonzero.  */
1131
1132 static void
1133 warn_for_collisions_1 (tree written, tree writer, struct tlist *list,
1134                        int only_writes)
1135 {
1136   struct tlist *tmp;
1137
1138   /* Avoid duplicate warnings.  */
1139   for (tmp = warned_ids; tmp; tmp = tmp->next)
1140     if (tmp->expr == written)
1141       return;
1142
1143   while (list)
1144     {
1145       if (list->expr == written
1146           && list->writer != writer
1147           && (! only_writes || list->writer)
1148           && DECL_NAME (list->expr))
1149         {
1150           warned_ids = new_tlist (warned_ids, written, NULL_TREE);
1151           warning ("operation on %qs may be undefined",
1152                    IDENTIFIER_POINTER (DECL_NAME (list->expr)));
1153         }
1154       list = list->next;
1155     }
1156 }
1157
1158 /* Given a list LIST of references to variables, find whether any of these
1159    can cause conflicts due to missing sequence points.  */
1160
1161 static void
1162 warn_for_collisions (struct tlist *list)
1163 {
1164   struct tlist *tmp;
1165
1166   for (tmp = list; tmp; tmp = tmp->next)
1167     {
1168       if (tmp->writer)
1169         warn_for_collisions_1 (tmp->expr, tmp->writer, list, 0);
1170     }
1171 }
1172
1173 /* Return nonzero if X is a tree that can be verified by the sequence point
1174    warnings.  */
1175 static int
1176 warning_candidate_p (tree x)
1177 {
1178   return TREE_CODE (x) == VAR_DECL || TREE_CODE (x) == PARM_DECL;
1179 }
1180
1181 /* Walk the tree X, and record accesses to variables.  If X is written by the
1182    parent tree, WRITER is the parent.
1183    We store accesses in one of the two lists: PBEFORE_SP, and PNO_SP.  If this
1184    expression or its only operand forces a sequence point, then everything up
1185    to the sequence point is stored in PBEFORE_SP.  Everything else gets stored
1186    in PNO_SP.
1187    Once we return, we will have emitted warnings if any subexpression before
1188    such a sequence point could be undefined.  On a higher level, however, the
1189    sequence point may not be relevant, and we'll merge the two lists.
1190
1191    Example: (b++, a) + b;
1192    The call that processes the COMPOUND_EXPR will store the increment of B
1193    in PBEFORE_SP, and the use of A in PNO_SP.  The higher-level call that
1194    processes the PLUS_EXPR will need to merge the two lists so that
1195    eventually, all accesses end up on the same list (and we'll warn about the
1196    unordered subexpressions b++ and b.
1197
1198    A note on merging.  If we modify the former example so that our expression
1199    becomes
1200      (b++, b) + a
1201    care must be taken not simply to add all three expressions into the final
1202    PNO_SP list.  The function merge_tlist takes care of that by merging the
1203    before-SP list of the COMPOUND_EXPR into its after-SP list in a special
1204    way, so that no more than one access to B is recorded.  */
1205
1206 static void
1207 verify_tree (tree x, struct tlist **pbefore_sp, struct tlist **pno_sp,
1208              tree writer)
1209 {
1210   struct tlist *tmp_before, *tmp_nosp, *tmp_list2, *tmp_list3;
1211   enum tree_code code;
1212   enum tree_code_class cl;
1213
1214   /* X may be NULL if it is the operand of an empty statement expression
1215      ({ }).  */
1216   if (x == NULL)
1217     return;
1218
1219  restart:
1220   code = TREE_CODE (x);
1221   cl = TREE_CODE_CLASS (code);
1222
1223   if (warning_candidate_p (x))
1224     {
1225       *pno_sp = new_tlist (*pno_sp, x, writer);
1226       return;
1227     }
1228
1229   switch (code)
1230     {
1231     case CONSTRUCTOR:
1232       return;
1233
1234     case COMPOUND_EXPR:
1235     case TRUTH_ANDIF_EXPR:
1236     case TRUTH_ORIF_EXPR:
1237       tmp_before = tmp_nosp = tmp_list3 = 0;
1238       verify_tree (TREE_OPERAND (x, 0), &tmp_before, &tmp_nosp, NULL_TREE);
1239       warn_for_collisions (tmp_nosp);
1240       merge_tlist (pbefore_sp, tmp_before, 0);
1241       merge_tlist (pbefore_sp, tmp_nosp, 0);
1242       verify_tree (TREE_OPERAND (x, 1), &tmp_list3, pno_sp, NULL_TREE);
1243       merge_tlist (pbefore_sp, tmp_list3, 0);
1244       return;
1245
1246     case COND_EXPR:
1247       tmp_before = tmp_list2 = 0;
1248       verify_tree (TREE_OPERAND (x, 0), &tmp_before, &tmp_list2, NULL_TREE);
1249       warn_for_collisions (tmp_list2);
1250       merge_tlist (pbefore_sp, tmp_before, 0);
1251       merge_tlist (pbefore_sp, tmp_list2, 1);
1252
1253       tmp_list3 = tmp_nosp = 0;
1254       verify_tree (TREE_OPERAND (x, 1), &tmp_list3, &tmp_nosp, NULL_TREE);
1255       warn_for_collisions (tmp_nosp);
1256       merge_tlist (pbefore_sp, tmp_list3, 0);
1257
1258       tmp_list3 = tmp_list2 = 0;
1259       verify_tree (TREE_OPERAND (x, 2), &tmp_list3, &tmp_list2, NULL_TREE);
1260       warn_for_collisions (tmp_list2);
1261       merge_tlist (pbefore_sp, tmp_list3, 0);
1262       /* Rather than add both tmp_nosp and tmp_list2, we have to merge the
1263          two first, to avoid warning for (a ? b++ : b++).  */
1264       merge_tlist (&tmp_nosp, tmp_list2, 0);
1265       add_tlist (pno_sp, tmp_nosp, NULL_TREE, 0);
1266       return;
1267
1268     case PREDECREMENT_EXPR:
1269     case PREINCREMENT_EXPR:
1270     case POSTDECREMENT_EXPR:
1271     case POSTINCREMENT_EXPR:
1272       verify_tree (TREE_OPERAND (x, 0), pno_sp, pno_sp, x);
1273       return;
1274
1275     case MODIFY_EXPR:
1276       tmp_before = tmp_nosp = tmp_list3 = 0;
1277       verify_tree (TREE_OPERAND (x, 1), &tmp_before, &tmp_nosp, NULL_TREE);
1278       verify_tree (TREE_OPERAND (x, 0), &tmp_list3, &tmp_list3, x);
1279       /* Expressions inside the LHS are not ordered wrt. the sequence points
1280          in the RHS.  Example:
1281            *a = (a++, 2)
1282          Despite the fact that the modification of "a" is in the before_sp
1283          list (tmp_before), it conflicts with the use of "a" in the LHS.
1284          We can handle this by adding the contents of tmp_list3
1285          to those of tmp_before, and redoing the collision warnings for that
1286          list.  */
1287       add_tlist (&tmp_before, tmp_list3, x, 1);
1288       warn_for_collisions (tmp_before);
1289       /* Exclude the LHS itself here; we first have to merge it into the
1290          tmp_nosp list.  This is done to avoid warning for "a = a"; if we
1291          didn't exclude the LHS, we'd get it twice, once as a read and once
1292          as a write.  */
1293       add_tlist (pno_sp, tmp_list3, x, 0);
1294       warn_for_collisions_1 (TREE_OPERAND (x, 0), x, tmp_nosp, 1);
1295
1296       merge_tlist (pbefore_sp, tmp_before, 0);
1297       if (warning_candidate_p (TREE_OPERAND (x, 0)))
1298         merge_tlist (&tmp_nosp, new_tlist (NULL, TREE_OPERAND (x, 0), x), 0);
1299       add_tlist (pno_sp, tmp_nosp, NULL_TREE, 1);
1300       return;
1301
1302     case CALL_EXPR:
1303       /* We need to warn about conflicts among arguments and conflicts between
1304          args and the function address.  Side effects of the function address,
1305          however, are not ordered by the sequence point of the call.  */
1306       tmp_before = tmp_nosp = tmp_list2 = tmp_list3 = 0;
1307       verify_tree (TREE_OPERAND (x, 0), &tmp_before, &tmp_nosp, NULL_TREE);
1308       if (TREE_OPERAND (x, 1))
1309         verify_tree (TREE_OPERAND (x, 1), &tmp_list2, &tmp_list3, NULL_TREE);
1310       merge_tlist (&tmp_list3, tmp_list2, 0);
1311       add_tlist (&tmp_before, tmp_list3, NULL_TREE, 0);
1312       add_tlist (&tmp_before, tmp_nosp, NULL_TREE, 0);
1313       warn_for_collisions (tmp_before);
1314       add_tlist (pbefore_sp, tmp_before, NULL_TREE, 0);
1315       return;
1316
1317     case TREE_LIST:
1318       /* Scan all the list, e.g. indices of multi dimensional array.  */
1319       while (x)
1320         {
1321           tmp_before = tmp_nosp = 0;
1322           verify_tree (TREE_VALUE (x), &tmp_before, &tmp_nosp, NULL_TREE);
1323           merge_tlist (&tmp_nosp, tmp_before, 0);
1324           add_tlist (pno_sp, tmp_nosp, NULL_TREE, 0);
1325           x = TREE_CHAIN (x);
1326         }
1327       return;
1328
1329     case SAVE_EXPR:
1330       {
1331         struct tlist_cache *t;
1332         for (t = save_expr_cache; t; t = t->next)
1333           if (t->expr == x)
1334             break;
1335
1336         if (! t)
1337           {
1338             t = XOBNEW (&tlist_obstack, struct tlist_cache);
1339             t->next = save_expr_cache;
1340             t->expr = x;
1341             save_expr_cache = t;
1342
1343             tmp_before = tmp_nosp = 0;
1344             verify_tree (TREE_OPERAND (x, 0), &tmp_before, &tmp_nosp, NULL_TREE);
1345             warn_for_collisions (tmp_nosp);
1346
1347             tmp_list3 = 0;
1348             while (tmp_nosp)
1349               {
1350                 struct tlist *t = tmp_nosp;
1351                 tmp_nosp = t->next;
1352                 merge_tlist (&tmp_list3, t, 0);
1353               }
1354             t->cache_before_sp = tmp_before;
1355             t->cache_after_sp = tmp_list3;
1356           }
1357         merge_tlist (pbefore_sp, t->cache_before_sp, 1);
1358         add_tlist (pno_sp, t->cache_after_sp, NULL_TREE, 1);
1359         return;
1360       }
1361
1362     default:
1363       /* For other expressions, simply recurse on their operands.
1364          Manual tail recursion for unary expressions.
1365          Other non-expressions need not be processed.  */
1366       if (cl == tcc_unary)
1367         {
1368           if (first_rtl_op (code) == 0)
1369             return;
1370           x = TREE_OPERAND (x, 0);
1371           writer = 0;
1372           goto restart;
1373         }
1374       else if (IS_EXPR_CODE_CLASS (cl))
1375         {
1376           int lp;
1377           int max = first_rtl_op (TREE_CODE (x));
1378           for (lp = 0; lp < max; lp++)
1379             {
1380               tmp_before = tmp_nosp = 0;
1381               verify_tree (TREE_OPERAND (x, lp), &tmp_before, &tmp_nosp, 0);
1382               merge_tlist (&tmp_nosp, tmp_before, 0);
1383               add_tlist (pno_sp, tmp_nosp, NULL_TREE, 0);
1384             }
1385         }
1386       return;
1387     }
1388 }
1389
1390 /* Try to warn for undefined behavior in EXPR due to missing sequence
1391    points.  */
1392
1393 void
1394 verify_sequence_points (tree expr)
1395 {
1396   struct tlist *before_sp = 0, *after_sp = 0;
1397
1398   warned_ids = 0;
1399   save_expr_cache = 0;
1400   if (tlist_firstobj == 0)
1401     {
1402       gcc_obstack_init (&tlist_obstack);
1403       tlist_firstobj = (char *) obstack_alloc (&tlist_obstack, 0);
1404     }
1405
1406   verify_tree (expr, &before_sp, &after_sp, 0);
1407   warn_for_collisions (after_sp);
1408   obstack_free (&tlist_obstack, tlist_firstobj);
1409 }
1410 \f
1411 /* Validate the expression after `case' and apply default promotions.  */
1412
1413 static tree
1414 check_case_value (tree value)
1415 {
1416   if (value == NULL_TREE)
1417     return value;
1418
1419   /* Strip NON_LVALUE_EXPRs since we aren't using as an lvalue.  */
1420   STRIP_TYPE_NOPS (value);
1421   /* In C++, the following is allowed:
1422
1423        const int i = 3;
1424        switch (...) { case i: ... }
1425
1426      So, we try to reduce the VALUE to a constant that way.  */
1427   if (c_dialect_cxx ())
1428     {
1429       value = decl_constant_value (value);
1430       STRIP_TYPE_NOPS (value);
1431       value = fold (value);
1432     }
1433
1434   if (TREE_CODE (value) != INTEGER_CST
1435       && value != error_mark_node)
1436     {
1437       error ("case label does not reduce to an integer constant");
1438       value = error_mark_node;
1439     }
1440   else
1441     /* Promote char or short to int.  */
1442     value = default_conversion (value);
1443
1444   constant_expression_warning (value);
1445
1446   return value;
1447 }
1448 \f
1449 /* See if the case values LOW and HIGH are in the range of the original
1450    type (i.e. before the default conversion to int) of the switch testing
1451    expression.
1452    TYPE is the promoted type of the testing expression, and ORIG_TYPE is
1453    the type before promoting it.  CASE_LOW_P is a pointer to the lower
1454    bound of the case label, and CASE_HIGH_P is the upper bound or NULL
1455    if the case is not a case range.
1456    The caller has to make sure that we are not called with NULL for
1457    CASE_LOW_P (i.e. the default case).
1458    Returns true if the case label is in range of ORIG_TYPE (satured or
1459    untouched) or false if the label is out of range.  */
1460
1461 static bool
1462 check_case_bounds (tree type, tree orig_type,
1463                    tree *case_low_p, tree *case_high_p)
1464 {
1465   tree min_value, max_value;
1466   tree case_low = *case_low_p;
1467   tree case_high = case_high_p ? *case_high_p : case_low;
1468
1469   /* If there was a problem with the original type, do nothing.  */
1470   if (orig_type == error_mark_node)
1471     return true;
1472
1473   min_value = TYPE_MIN_VALUE (orig_type);
1474   max_value = TYPE_MAX_VALUE (orig_type);
1475
1476   /* Case label is less than minimum for type.  */
1477   if (tree_int_cst_compare (case_low, min_value) < 0
1478       && tree_int_cst_compare (case_high, min_value) < 0)
1479     {
1480       warning ("case label value is less than minimum value for type");
1481       return false;
1482     }
1483
1484   /* Case value is greater than maximum for type.  */
1485   if (tree_int_cst_compare (case_low, max_value) > 0
1486       && tree_int_cst_compare (case_high, max_value) > 0)
1487     {
1488       warning ("case label value exceeds maximum value for type");
1489       return false;
1490     }
1491
1492   /* Saturate lower case label value to minimum.  */
1493   if (tree_int_cst_compare (case_high, min_value) >= 0
1494       && tree_int_cst_compare (case_low, min_value) < 0)
1495     {
1496       warning ("lower value in case label range"
1497                " less than minimum value for type");
1498       case_low = min_value;
1499     }
1500
1501   /* Saturate upper case label value to maximum.  */
1502   if (tree_int_cst_compare (case_low, max_value) <= 0
1503       && tree_int_cst_compare (case_high, max_value) > 0)
1504     {
1505       warning ("upper value in case label range"
1506                " exceeds maximum value for type");
1507       case_high = max_value;
1508     }
1509
1510   if (*case_low_p != case_low)
1511     *case_low_p = convert (type, case_low);
1512   if (case_high_p && *case_high_p != case_high)
1513     *case_high_p = convert (type, case_high);
1514
1515   return true;
1516 }
1517 \f
1518 /* Return an integer type with BITS bits of precision,
1519    that is unsigned if UNSIGNEDP is nonzero, otherwise signed.  */
1520
1521 tree
1522 c_common_type_for_size (unsigned int bits, int unsignedp)
1523 {
1524   if (bits == TYPE_PRECISION (integer_type_node))
1525     return unsignedp ? unsigned_type_node : integer_type_node;
1526
1527   if (bits == TYPE_PRECISION (signed_char_type_node))
1528     return unsignedp ? unsigned_char_type_node : signed_char_type_node;
1529
1530   if (bits == TYPE_PRECISION (short_integer_type_node))
1531     return unsignedp ? short_unsigned_type_node : short_integer_type_node;
1532
1533   if (bits == TYPE_PRECISION (long_integer_type_node))
1534     return unsignedp ? long_unsigned_type_node : long_integer_type_node;
1535
1536   if (bits == TYPE_PRECISION (long_long_integer_type_node))
1537     return (unsignedp ? long_long_unsigned_type_node
1538             : long_long_integer_type_node);
1539
1540   if (bits == TYPE_PRECISION (widest_integer_literal_type_node))
1541     return (unsignedp ? widest_unsigned_literal_type_node
1542             : widest_integer_literal_type_node);
1543
1544   if (bits <= TYPE_PRECISION (intQI_type_node))
1545     return unsignedp ? unsigned_intQI_type_node : intQI_type_node;
1546
1547   if (bits <= TYPE_PRECISION (intHI_type_node))
1548     return unsignedp ? unsigned_intHI_type_node : intHI_type_node;
1549
1550   if (bits <= TYPE_PRECISION (intSI_type_node))
1551     return unsignedp ? unsigned_intSI_type_node : intSI_type_node;
1552
1553   if (bits <= TYPE_PRECISION (intDI_type_node))
1554     return unsignedp ? unsigned_intDI_type_node : intDI_type_node;
1555
1556   return 0;
1557 }
1558
1559 /* Used for communication between c_common_type_for_mode and
1560    c_register_builtin_type.  */
1561 static GTY(()) tree registered_builtin_types;
1562
1563 /* Return a data type that has machine mode MODE.
1564    If the mode is an integer,
1565    then UNSIGNEDP selects between signed and unsigned types.  */
1566
1567 tree
1568 c_common_type_for_mode (enum machine_mode mode, int unsignedp)
1569 {
1570   tree t;
1571
1572   if (mode == TYPE_MODE (integer_type_node))
1573     return unsignedp ? unsigned_type_node : integer_type_node;
1574
1575   if (mode == TYPE_MODE (signed_char_type_node))
1576     return unsignedp ? unsigned_char_type_node : signed_char_type_node;
1577
1578   if (mode == TYPE_MODE (short_integer_type_node))
1579     return unsignedp ? short_unsigned_type_node : short_integer_type_node;
1580
1581   if (mode == TYPE_MODE (long_integer_type_node))
1582     return unsignedp ? long_unsigned_type_node : long_integer_type_node;
1583
1584   if (mode == TYPE_MODE (long_long_integer_type_node))
1585     return unsignedp ? long_long_unsigned_type_node : long_long_integer_type_node;
1586
1587   if (mode == TYPE_MODE (widest_integer_literal_type_node))
1588     return unsignedp ? widest_unsigned_literal_type_node
1589                      : widest_integer_literal_type_node;
1590
1591   if (mode == QImode)
1592     return unsignedp ? unsigned_intQI_type_node : intQI_type_node;
1593
1594   if (mode == HImode)
1595     return unsignedp ? unsigned_intHI_type_node : intHI_type_node;
1596
1597   if (mode == SImode)
1598     return unsignedp ? unsigned_intSI_type_node : intSI_type_node;
1599
1600   if (mode == DImode)
1601     return unsignedp ? unsigned_intDI_type_node : intDI_type_node;
1602
1603 #if HOST_BITS_PER_WIDE_INT >= 64
1604   if (mode == TYPE_MODE (intTI_type_node))
1605     return unsignedp ? unsigned_intTI_type_node : intTI_type_node;
1606 #endif
1607
1608   if (mode == TYPE_MODE (float_type_node))
1609     return float_type_node;
1610
1611   if (mode == TYPE_MODE (double_type_node))
1612     return double_type_node;
1613
1614   if (mode == TYPE_MODE (long_double_type_node))
1615     return long_double_type_node;
1616
1617   if (mode == TYPE_MODE (void_type_node))
1618     return void_type_node;
1619
1620   if (mode == TYPE_MODE (build_pointer_type (char_type_node)))
1621     return unsignedp ? make_unsigned_type (mode) : make_signed_type (mode);
1622
1623   if (mode == TYPE_MODE (build_pointer_type (integer_type_node)))
1624     return unsignedp ? make_unsigned_type (mode) : make_signed_type (mode);
1625
1626   if (VECTOR_MODE_P (mode))
1627     {
1628       enum machine_mode inner_mode = GET_MODE_INNER (mode);
1629       tree inner_type = c_common_type_for_mode (inner_mode, unsignedp);
1630       if (inner_type != NULL_TREE)
1631         return build_vector_type_for_mode (inner_type, mode);
1632     }
1633
1634   for (t = registered_builtin_types; t; t = TREE_CHAIN (t))
1635     if (TYPE_MODE (TREE_VALUE (t)) == mode)
1636       return TREE_VALUE (t);
1637
1638   return 0;
1639 }
1640
1641 /* Return an unsigned type the same as TYPE in other respects.  */
1642 tree
1643 c_common_unsigned_type (tree type)
1644 {
1645   tree type1 = TYPE_MAIN_VARIANT (type);
1646   if (type1 == signed_char_type_node || type1 == char_type_node)
1647     return unsigned_char_type_node;
1648   if (type1 == integer_type_node)
1649     return unsigned_type_node;
1650   if (type1 == short_integer_type_node)
1651     return short_unsigned_type_node;
1652   if (type1 == long_integer_type_node)
1653     return long_unsigned_type_node;
1654   if (type1 == long_long_integer_type_node)
1655     return long_long_unsigned_type_node;
1656   if (type1 == widest_integer_literal_type_node)
1657     return widest_unsigned_literal_type_node;
1658 #if HOST_BITS_PER_WIDE_INT >= 64
1659   if (type1 == intTI_type_node)
1660     return unsigned_intTI_type_node;
1661 #endif
1662   if (type1 == intDI_type_node)
1663     return unsigned_intDI_type_node;
1664   if (type1 == intSI_type_node)
1665     return unsigned_intSI_type_node;
1666   if (type1 == intHI_type_node)
1667     return unsigned_intHI_type_node;
1668   if (type1 == intQI_type_node)
1669     return unsigned_intQI_type_node;
1670
1671   return c_common_signed_or_unsigned_type (1, type);
1672 }
1673
1674 /* Return a signed type the same as TYPE in other respects.  */
1675
1676 tree
1677 c_common_signed_type (tree type)
1678 {
1679   tree type1 = TYPE_MAIN_VARIANT (type);
1680   if (type1 == unsigned_char_type_node || type1 == char_type_node)
1681     return signed_char_type_node;
1682   if (type1 == unsigned_type_node)
1683     return integer_type_node;
1684   if (type1 == short_unsigned_type_node)
1685     return short_integer_type_node;
1686   if (type1 == long_unsigned_type_node)
1687     return long_integer_type_node;
1688   if (type1 == long_long_unsigned_type_node)
1689     return long_long_integer_type_node;
1690   if (type1 == widest_unsigned_literal_type_node)
1691     return widest_integer_literal_type_node;
1692 #if HOST_BITS_PER_WIDE_INT >= 64
1693   if (type1 == unsigned_intTI_type_node)
1694     return intTI_type_node;
1695 #endif
1696   if (type1 == unsigned_intDI_type_node)
1697     return intDI_type_node;
1698   if (type1 == unsigned_intSI_type_node)
1699     return intSI_type_node;
1700   if (type1 == unsigned_intHI_type_node)
1701     return intHI_type_node;
1702   if (type1 == unsigned_intQI_type_node)
1703     return intQI_type_node;
1704
1705   return c_common_signed_or_unsigned_type (0, type);
1706 }
1707
1708 /* Return a type the same as TYPE except unsigned or
1709    signed according to UNSIGNEDP.  */
1710
1711 tree
1712 c_common_signed_or_unsigned_type (int unsignedp, tree type)
1713 {
1714   if (! INTEGRAL_TYPE_P (type)
1715       || TYPE_UNSIGNED (type) == unsignedp)
1716     return type;
1717
1718   /* For ENUMERAL_TYPEs in C++, must check the mode of the types, not
1719      the precision; they have precision set to match their range, but
1720      may use a wider mode to match an ABI.  If we change modes, we may
1721      wind up with bad conversions.  For INTEGER_TYPEs in C, must check
1722      the precision as well, so as to yield correct results for
1723      bit-field types.  C++ does not have these separate bit-field
1724      types, and producing a signed or unsigned variant of an
1725      ENUMERAL_TYPE may cause other problems as well.  */
1726
1727 #define TYPE_OK(node)                                                       \
1728   (TYPE_MODE (type) == TYPE_MODE (node)                                     \
1729    && (c_dialect_cxx () || TYPE_PRECISION (type) == TYPE_PRECISION (node)))
1730   if (TYPE_OK (signed_char_type_node))
1731     return unsignedp ? unsigned_char_type_node : signed_char_type_node;
1732   if (TYPE_OK (integer_type_node))
1733     return unsignedp ? unsigned_type_node : integer_type_node;
1734   if (TYPE_OK (short_integer_type_node))
1735     return unsignedp ? short_unsigned_type_node : short_integer_type_node;
1736   if (TYPE_OK (long_integer_type_node))
1737     return unsignedp ? long_unsigned_type_node : long_integer_type_node;
1738   if (TYPE_OK (long_long_integer_type_node))
1739     return (unsignedp ? long_long_unsigned_type_node
1740             : long_long_integer_type_node);
1741   if (TYPE_OK (widest_integer_literal_type_node))
1742     return (unsignedp ? widest_unsigned_literal_type_node
1743             : widest_integer_literal_type_node);
1744
1745 #if HOST_BITS_PER_WIDE_INT >= 64
1746   if (TYPE_OK (intTI_type_node))
1747     return unsignedp ? unsigned_intTI_type_node : intTI_type_node;
1748 #endif
1749   if (TYPE_OK (intDI_type_node))
1750     return unsignedp ? unsigned_intDI_type_node : intDI_type_node;
1751   if (TYPE_OK (intSI_type_node))
1752     return unsignedp ? unsigned_intSI_type_node : intSI_type_node;
1753   if (TYPE_OK (intHI_type_node))
1754     return unsignedp ? unsigned_intHI_type_node : intHI_type_node;
1755   if (TYPE_OK (intQI_type_node))
1756     return unsignedp ? unsigned_intQI_type_node : intQI_type_node;
1757 #undef TYPE_OK
1758
1759   if (c_dialect_cxx ())
1760     return type;
1761   else
1762     return build_nonstandard_integer_type (TYPE_PRECISION (type), unsignedp);
1763 }
1764
1765 /* The C version of the register_builtin_type langhook.  */
1766
1767 void
1768 c_register_builtin_type (tree type, const char* name)
1769 {
1770   tree decl;
1771
1772   decl = build_decl (TYPE_DECL, get_identifier (name), type);
1773   DECL_ARTIFICIAL (decl) = 1;
1774   if (!TYPE_NAME (type))
1775     TYPE_NAME (type) = decl;
1776   pushdecl (decl);
1777
1778   registered_builtin_types = tree_cons (0, type, registered_builtin_types);
1779 }
1780
1781 \f
1782 /* Return the minimum number of bits needed to represent VALUE in a
1783    signed or unsigned type, UNSIGNEDP says which.  */
1784
1785 unsigned int
1786 min_precision (tree value, int unsignedp)
1787 {
1788   int log;
1789
1790   /* If the value is negative, compute its negative minus 1.  The latter
1791      adjustment is because the absolute value of the largest negative value
1792      is one larger than the largest positive value.  This is equivalent to
1793      a bit-wise negation, so use that operation instead.  */
1794
1795   if (tree_int_cst_sgn (value) < 0)
1796     value = fold (build1 (BIT_NOT_EXPR, TREE_TYPE (value), value));
1797
1798   /* Return the number of bits needed, taking into account the fact
1799      that we need one more bit for a signed than unsigned type.  */
1800
1801   if (integer_zerop (value))
1802     log = 0;
1803   else
1804     log = tree_floor_log2 (value);
1805
1806   return log + 1 + ! unsignedp;
1807 }
1808 \f
1809 /* Print an error message for invalid operands to arith operation
1810    CODE.  NOP_EXPR is used as a special case (see
1811    c_common_truthvalue_conversion).  */
1812
1813 void
1814 binary_op_error (enum tree_code code)
1815 {
1816   const char *opname;
1817
1818   switch (code)
1819     {
1820     case NOP_EXPR:
1821       error ("invalid truth-value expression");
1822       return;
1823
1824     case PLUS_EXPR:
1825       opname = "+"; break;
1826     case MINUS_EXPR:
1827       opname = "-"; break;
1828     case MULT_EXPR:
1829       opname = "*"; break;
1830     case MAX_EXPR:
1831       opname = "max"; break;
1832     case MIN_EXPR:
1833       opname = "min"; break;
1834     case EQ_EXPR:
1835       opname = "=="; break;
1836     case NE_EXPR:
1837       opname = "!="; break;
1838     case LE_EXPR:
1839       opname = "<="; break;
1840     case GE_EXPR:
1841       opname = ">="; break;
1842     case LT_EXPR:
1843       opname = "<"; break;
1844     case GT_EXPR:
1845       opname = ">"; break;
1846     case LSHIFT_EXPR:
1847       opname = "<<"; break;
1848     case RSHIFT_EXPR:
1849       opname = ">>"; break;
1850     case TRUNC_MOD_EXPR:
1851     case FLOOR_MOD_EXPR:
1852       opname = "%"; break;
1853     case TRUNC_DIV_EXPR:
1854     case FLOOR_DIV_EXPR:
1855       opname = "/"; break;
1856     case BIT_AND_EXPR:
1857       opname = "&"; break;
1858     case BIT_IOR_EXPR:
1859       opname = "|"; break;
1860     case TRUTH_ANDIF_EXPR:
1861       opname = "&&"; break;
1862     case TRUTH_ORIF_EXPR:
1863       opname = "||"; break;
1864     case BIT_XOR_EXPR:
1865       opname = "^"; break;
1866     case LROTATE_EXPR:
1867     case RROTATE_EXPR:
1868       opname = "rotate"; break;
1869     default:
1870       opname = "unknown"; break;
1871     }
1872   error ("invalid operands to binary %s", opname);
1873 }
1874 \f
1875 /* Subroutine of build_binary_op, used for comparison operations.
1876    See if the operands have both been converted from subword integer types
1877    and, if so, perhaps change them both back to their original type.
1878    This function is also responsible for converting the two operands
1879    to the proper common type for comparison.
1880
1881    The arguments of this function are all pointers to local variables
1882    of build_binary_op: OP0_PTR is &OP0, OP1_PTR is &OP1,
1883    RESTYPE_PTR is &RESULT_TYPE and RESCODE_PTR is &RESULTCODE.
1884
1885    If this function returns nonzero, it means that the comparison has
1886    a constant value.  What this function returns is an expression for
1887    that value.  */
1888
1889 tree
1890 shorten_compare (tree *op0_ptr, tree *op1_ptr, tree *restype_ptr,
1891                  enum tree_code *rescode_ptr)
1892 {
1893   tree type;
1894   tree op0 = *op0_ptr;
1895   tree op1 = *op1_ptr;
1896   int unsignedp0, unsignedp1;
1897   int real1, real2;
1898   tree primop0, primop1;
1899   enum tree_code code = *rescode_ptr;
1900
1901   /* Throw away any conversions to wider types
1902      already present in the operands.  */
1903
1904   primop0 = get_narrower (op0, &unsignedp0);
1905   primop1 = get_narrower (op1, &unsignedp1);
1906
1907   /* Handle the case that OP0 does not *contain* a conversion
1908      but it *requires* conversion to FINAL_TYPE.  */
1909
1910   if (op0 == primop0 && TREE_TYPE (op0) != *restype_ptr)
1911     unsignedp0 = TYPE_UNSIGNED (TREE_TYPE (op0));
1912   if (op1 == primop1 && TREE_TYPE (op1) != *restype_ptr)
1913     unsignedp1 = TYPE_UNSIGNED (TREE_TYPE (op1));
1914
1915   /* If one of the operands must be floated, we cannot optimize.  */
1916   real1 = TREE_CODE (TREE_TYPE (primop0)) == REAL_TYPE;
1917   real2 = TREE_CODE (TREE_TYPE (primop1)) == REAL_TYPE;
1918
1919   /* If first arg is constant, swap the args (changing operation
1920      so value is preserved), for canonicalization.  Don't do this if
1921      the second arg is 0.  */
1922
1923   if (TREE_CONSTANT (primop0)
1924       && ! integer_zerop (primop1) && ! real_zerop (primop1))
1925     {
1926       tree tem = primop0;
1927       int temi = unsignedp0;
1928       primop0 = primop1;
1929       primop1 = tem;
1930       tem = op0;
1931       op0 = op1;
1932       op1 = tem;
1933       *op0_ptr = op0;
1934       *op1_ptr = op1;
1935       unsignedp0 = unsignedp1;
1936       unsignedp1 = temi;
1937       temi = real1;
1938       real1 = real2;
1939       real2 = temi;
1940
1941       switch (code)
1942         {
1943         case LT_EXPR:
1944           code = GT_EXPR;
1945           break;
1946         case GT_EXPR:
1947           code = LT_EXPR;
1948           break;
1949         case LE_EXPR:
1950           code = GE_EXPR;
1951           break;
1952         case GE_EXPR:
1953           code = LE_EXPR;
1954           break;
1955         default:
1956           break;
1957         }
1958       *rescode_ptr = code;
1959     }
1960
1961   /* If comparing an integer against a constant more bits wide,
1962      maybe we can deduce a value of 1 or 0 independent of the data.
1963      Or else truncate the constant now
1964      rather than extend the variable at run time.
1965
1966      This is only interesting if the constant is the wider arg.
1967      Also, it is not safe if the constant is unsigned and the
1968      variable arg is signed, since in this case the variable
1969      would be sign-extended and then regarded as unsigned.
1970      Our technique fails in this case because the lowest/highest
1971      possible unsigned results don't follow naturally from the
1972      lowest/highest possible values of the variable operand.
1973      For just EQ_EXPR and NE_EXPR there is another technique that
1974      could be used: see if the constant can be faithfully represented
1975      in the other operand's type, by truncating it and reextending it
1976      and see if that preserves the constant's value.  */
1977
1978   if (!real1 && !real2
1979       && TREE_CODE (primop1) == INTEGER_CST
1980       && TYPE_PRECISION (TREE_TYPE (primop0)) < TYPE_PRECISION (*restype_ptr))
1981     {
1982       int min_gt, max_gt, min_lt, max_lt;
1983       tree maxval, minval;
1984       /* 1 if comparison is nominally unsigned.  */
1985       int unsignedp = TYPE_UNSIGNED (*restype_ptr);
1986       tree val;
1987
1988       type = c_common_signed_or_unsigned_type (unsignedp0,
1989                                                TREE_TYPE (primop0));
1990
1991       /* In C, if TYPE is an enumeration, then we need to get its
1992          min/max values from its underlying integral type, not the
1993          enumerated type itself.  In C++, TYPE_MAX_VALUE and
1994          TYPE_MIN_VALUE have already been set correctly on the
1995          enumeration type.  */
1996       if (!c_dialect_cxx() && TREE_CODE (type) == ENUMERAL_TYPE)
1997         type = c_common_type_for_size (TYPE_PRECISION (type), unsignedp0);
1998
1999       maxval = TYPE_MAX_VALUE (type);
2000       minval = TYPE_MIN_VALUE (type);
2001
2002       if (unsignedp && !unsignedp0)
2003         *restype_ptr = c_common_signed_type (*restype_ptr);
2004
2005       if (TREE_TYPE (primop1) != *restype_ptr)
2006         {
2007           /* Convert primop1 to target type, but do not introduce
2008              additional overflow.  We know primop1 is an int_cst.  */
2009           tree tmp = build_int_cst_wide (*restype_ptr,
2010                                          TREE_INT_CST_LOW (primop1),
2011                                          TREE_INT_CST_HIGH (primop1));
2012
2013           primop1 = force_fit_type (tmp, 0, TREE_OVERFLOW (primop1),
2014                                     TREE_CONSTANT_OVERFLOW (primop1));
2015         }
2016       if (type != *restype_ptr)
2017         {
2018           minval = convert (*restype_ptr, minval);
2019           maxval = convert (*restype_ptr, maxval);
2020         }
2021
2022       if (unsignedp && unsignedp0)
2023         {
2024           min_gt = INT_CST_LT_UNSIGNED (primop1, minval);
2025           max_gt = INT_CST_LT_UNSIGNED (primop1, maxval);
2026           min_lt = INT_CST_LT_UNSIGNED (minval, primop1);
2027           max_lt = INT_CST_LT_UNSIGNED (maxval, primop1);
2028         }
2029       else
2030         {
2031           min_gt = INT_CST_LT (primop1, minval);
2032           max_gt = INT_CST_LT (primop1, maxval);
2033           min_lt = INT_CST_LT (minval, primop1);
2034           max_lt = INT_CST_LT (maxval, primop1);
2035         }
2036
2037       val = 0;
2038       /* This used to be a switch, but Genix compiler can't handle that.  */
2039       if (code == NE_EXPR)
2040         {
2041           if (max_lt || min_gt)
2042             val = truthvalue_true_node;
2043         }
2044       else if (code == EQ_EXPR)
2045         {
2046           if (max_lt || min_gt)
2047             val = truthvalue_false_node;
2048         }
2049       else if (code == LT_EXPR)
2050         {
2051           if (max_lt)
2052             val = truthvalue_true_node;
2053           if (!min_lt)
2054             val = truthvalue_false_node;
2055         }
2056       else if (code == GT_EXPR)
2057         {
2058           if (min_gt)
2059             val = truthvalue_true_node;
2060           if (!max_gt)
2061             val = truthvalue_false_node;
2062         }
2063       else if (code == LE_EXPR)
2064         {
2065           if (!max_gt)
2066             val = truthvalue_true_node;
2067           if (min_gt)
2068             val = truthvalue_false_node;
2069         }
2070       else if (code == GE_EXPR)
2071         {
2072           if (!min_lt)
2073             val = truthvalue_true_node;
2074           if (max_lt)
2075             val = truthvalue_false_node;
2076         }
2077
2078       /* If primop0 was sign-extended and unsigned comparison specd,
2079          we did a signed comparison above using the signed type bounds.
2080          But the comparison we output must be unsigned.
2081
2082          Also, for inequalities, VAL is no good; but if the signed
2083          comparison had *any* fixed result, it follows that the
2084          unsigned comparison just tests the sign in reverse
2085          (positive values are LE, negative ones GE).
2086          So we can generate an unsigned comparison
2087          against an extreme value of the signed type.  */
2088
2089       if (unsignedp && !unsignedp0)
2090         {
2091           if (val != 0)
2092             switch (code)
2093               {
2094               case LT_EXPR:
2095               case GE_EXPR:
2096                 primop1 = TYPE_MIN_VALUE (type);
2097                 val = 0;
2098                 break;
2099
2100               case LE_EXPR:
2101               case GT_EXPR:
2102                 primop1 = TYPE_MAX_VALUE (type);
2103                 val = 0;
2104                 break;
2105
2106               default:
2107                 break;
2108               }
2109           type = c_common_unsigned_type (type);
2110         }
2111
2112       if (TREE_CODE (primop0) != INTEGER_CST)
2113         {
2114           if (val == truthvalue_false_node)
2115             warning ("comparison is always false due to limited range of data type");
2116           if (val == truthvalue_true_node)
2117             warning ("comparison is always true due to limited range of data type");
2118         }
2119
2120       if (val != 0)
2121         {
2122           /* Don't forget to evaluate PRIMOP0 if it has side effects.  */
2123           if (TREE_SIDE_EFFECTS (primop0))
2124             return build2 (COMPOUND_EXPR, TREE_TYPE (val), primop0, val);
2125           return val;
2126         }
2127
2128       /* Value is not predetermined, but do the comparison
2129          in the type of the operand that is not constant.
2130          TYPE is already properly set.  */
2131     }
2132   else if (real1 && real2
2133            && (TYPE_PRECISION (TREE_TYPE (primop0))
2134                == TYPE_PRECISION (TREE_TYPE (primop1))))
2135     type = TREE_TYPE (primop0);
2136
2137   /* If args' natural types are both narrower than nominal type
2138      and both extend in the same manner, compare them
2139      in the type of the wider arg.
2140      Otherwise must actually extend both to the nominal
2141      common type lest different ways of extending
2142      alter the result.
2143      (eg, (short)-1 == (unsigned short)-1  should be 0.)  */
2144
2145   else if (unsignedp0 == unsignedp1 && real1 == real2
2146            && TYPE_PRECISION (TREE_TYPE (primop0)) < TYPE_PRECISION (*restype_ptr)
2147            && TYPE_PRECISION (TREE_TYPE (primop1)) < TYPE_PRECISION (*restype_ptr))
2148     {
2149       type = common_type (TREE_TYPE (primop0), TREE_TYPE (primop1));
2150       type = c_common_signed_or_unsigned_type (unsignedp0
2151                                                || TYPE_UNSIGNED (*restype_ptr),
2152                                                type);
2153       /* Make sure shorter operand is extended the right way
2154          to match the longer operand.  */
2155       primop0
2156         = convert (c_common_signed_or_unsigned_type (unsignedp0,
2157                                                      TREE_TYPE (primop0)),
2158                    primop0);
2159       primop1
2160         = convert (c_common_signed_or_unsigned_type (unsignedp1,
2161                                                      TREE_TYPE (primop1)),
2162                    primop1);
2163     }
2164   else
2165     {
2166       /* Here we must do the comparison on the nominal type
2167          using the args exactly as we received them.  */
2168       type = *restype_ptr;
2169       primop0 = op0;
2170       primop1 = op1;
2171
2172       if (!real1 && !real2 && integer_zerop (primop1)
2173           && TYPE_UNSIGNED (*restype_ptr))
2174         {
2175           tree value = 0;
2176           switch (code)
2177             {
2178             case GE_EXPR:
2179               /* All unsigned values are >= 0, so we warn if extra warnings
2180                  are requested.  However, if OP0 is a constant that is
2181                  >= 0, the signedness of the comparison isn't an issue,
2182                  so suppress the warning.  */
2183               if (extra_warnings && !in_system_header
2184                   && ! (TREE_CODE (primop0) == INTEGER_CST
2185                         && ! TREE_OVERFLOW (convert (c_common_signed_type (type),
2186                                                      primop0))))
2187                 warning ("comparison of unsigned expression >= 0 is always true");
2188               value = truthvalue_true_node;
2189               break;
2190
2191             case LT_EXPR:
2192               if (extra_warnings && !in_system_header
2193                   && ! (TREE_CODE (primop0) == INTEGER_CST
2194                         && ! TREE_OVERFLOW (convert (c_common_signed_type (type),
2195                                                      primop0))))
2196                 warning ("comparison of unsigned expression < 0 is always false");
2197               value = truthvalue_false_node;
2198               break;
2199
2200             default:
2201               break;
2202             }
2203
2204           if (value != 0)
2205             {
2206               /* Don't forget to evaluate PRIMOP0 if it has side effects.  */
2207               if (TREE_SIDE_EFFECTS (primop0))
2208                 return build2 (COMPOUND_EXPR, TREE_TYPE (value),
2209                                primop0, value);
2210               return value;
2211             }
2212         }
2213     }
2214
2215   *op0_ptr = convert (type, primop0);
2216   *op1_ptr = convert (type, primop1);
2217
2218   *restype_ptr = truthvalue_type_node;
2219
2220   return 0;
2221 }
2222 \f
2223 /* Return a tree for the sum or difference (RESULTCODE says which)
2224    of pointer PTROP and integer INTOP.  */
2225
2226 tree
2227 pointer_int_sum (enum tree_code resultcode, tree ptrop, tree intop)
2228 {
2229   tree size_exp;
2230
2231   /* The result is a pointer of the same type that is being added.  */
2232
2233   tree result_type = TREE_TYPE (ptrop);
2234
2235   if (TREE_CODE (TREE_TYPE (result_type)) == VOID_TYPE)
2236     {
2237       if (pedantic || warn_pointer_arith)
2238         pedwarn ("pointer of type %<void *%> used in arithmetic");
2239       size_exp = integer_one_node;
2240     }
2241   else if (TREE_CODE (TREE_TYPE (result_type)) == FUNCTION_TYPE)
2242     {
2243       if (pedantic || warn_pointer_arith)
2244         pedwarn ("pointer to a function used in arithmetic");
2245       size_exp = integer_one_node;
2246     }
2247   else if (TREE_CODE (TREE_TYPE (result_type)) == METHOD_TYPE)
2248     {
2249       if (pedantic || warn_pointer_arith)
2250         pedwarn ("pointer to member function used in arithmetic");
2251       size_exp = integer_one_node;
2252     }
2253   else
2254     size_exp = size_in_bytes (TREE_TYPE (result_type));
2255
2256   /* If what we are about to multiply by the size of the elements
2257      contains a constant term, apply distributive law
2258      and multiply that constant term separately.
2259      This helps produce common subexpressions.  */
2260
2261   if ((TREE_CODE (intop) == PLUS_EXPR || TREE_CODE (intop) == MINUS_EXPR)
2262       && ! TREE_CONSTANT (intop)
2263       && TREE_CONSTANT (TREE_OPERAND (intop, 1))
2264       && TREE_CONSTANT (size_exp)
2265       /* If the constant comes from pointer subtraction,
2266          skip this optimization--it would cause an error.  */
2267       && TREE_CODE (TREE_TYPE (TREE_OPERAND (intop, 0))) == INTEGER_TYPE
2268       /* If the constant is unsigned, and smaller than the pointer size,
2269          then we must skip this optimization.  This is because it could cause
2270          an overflow error if the constant is negative but INTOP is not.  */
2271       && (! TYPE_UNSIGNED (TREE_TYPE (intop))
2272           || (TYPE_PRECISION (TREE_TYPE (intop))
2273               == TYPE_PRECISION (TREE_TYPE (ptrop)))))
2274     {
2275       enum tree_code subcode = resultcode;
2276       tree int_type = TREE_TYPE (intop);
2277       if (TREE_CODE (intop) == MINUS_EXPR)
2278         subcode = (subcode == PLUS_EXPR ? MINUS_EXPR : PLUS_EXPR);
2279       /* Convert both subexpression types to the type of intop,
2280          because weird cases involving pointer arithmetic
2281          can result in a sum or difference with different type args.  */
2282       ptrop = build_binary_op (subcode, ptrop,
2283                                convert (int_type, TREE_OPERAND (intop, 1)), 1);
2284       intop = convert (int_type, TREE_OPERAND (intop, 0));
2285     }
2286
2287   /* Convert the integer argument to a type the same size as sizetype
2288      so the multiply won't overflow spuriously.  */
2289
2290   if (TYPE_PRECISION (TREE_TYPE (intop)) != TYPE_PRECISION (sizetype)
2291       || TYPE_UNSIGNED (TREE_TYPE (intop)) != TYPE_UNSIGNED (sizetype))
2292     intop = convert (c_common_type_for_size (TYPE_PRECISION (sizetype),
2293                                              TYPE_UNSIGNED (sizetype)), intop);
2294
2295   /* Replace the integer argument with a suitable product by the object size.
2296      Do this multiplication as signed, then convert to the appropriate
2297      pointer type (actually unsigned integral).  */
2298
2299   intop = convert (result_type,
2300                    build_binary_op (MULT_EXPR, intop,
2301                                     convert (TREE_TYPE (intop), size_exp), 1));
2302
2303   /* Create the sum or difference.  */
2304   return fold (build2 (resultcode, result_type, ptrop, intop));
2305 }
2306 \f
2307 /* Prepare expr to be an argument of a TRUTH_NOT_EXPR,
2308    or validate its data type for an `if' or `while' statement or ?..: exp.
2309
2310    This preparation consists of taking the ordinary
2311    representation of an expression expr and producing a valid tree
2312    boolean expression describing whether expr is nonzero.  We could
2313    simply always do build_binary_op (NE_EXPR, expr, truthvalue_false_node, 1),
2314    but we optimize comparisons, &&, ||, and !.
2315
2316    The resulting type should always be `truthvalue_type_node'.  */
2317
2318 tree
2319 c_common_truthvalue_conversion (tree expr)
2320 {
2321   if (TREE_CODE (expr) == ERROR_MARK)
2322     return expr;
2323
2324   if (TREE_CODE (expr) == FUNCTION_DECL)
2325     expr = build_unary_op (ADDR_EXPR, expr, 0);
2326
2327   switch (TREE_CODE (expr))
2328     {
2329     case EQ_EXPR:   case NE_EXPR:   case UNEQ_EXPR: case LTGT_EXPR:
2330     case LE_EXPR:   case GE_EXPR:   case LT_EXPR:   case GT_EXPR:
2331     case UNLE_EXPR: case UNGE_EXPR: case UNLT_EXPR: case UNGT_EXPR:
2332     case ORDERED_EXPR: case UNORDERED_EXPR:
2333     case TRUTH_ANDIF_EXPR:
2334     case TRUTH_ORIF_EXPR:
2335     case TRUTH_AND_EXPR:
2336     case TRUTH_OR_EXPR:
2337     case TRUTH_XOR_EXPR:
2338     case TRUTH_NOT_EXPR:
2339       TREE_TYPE (expr) = truthvalue_type_node;
2340       return expr;
2341
2342     case ERROR_MARK:
2343       return expr;
2344
2345     case INTEGER_CST:
2346       return integer_zerop (expr) ? truthvalue_false_node : truthvalue_true_node;
2347
2348     case REAL_CST:
2349       return real_zerop (expr) ? truthvalue_false_node : truthvalue_true_node;
2350
2351     case ADDR_EXPR:
2352       {
2353         if (TREE_CODE (TREE_OPERAND (expr, 0)) == FUNCTION_DECL
2354             && ! DECL_WEAK (TREE_OPERAND (expr, 0)))
2355           {
2356             /* Common Ada/Pascal programmer's mistake.  We always warn
2357                about this since it is so bad.  */
2358             warning ("the address of %qD, will always evaluate as %<true%>",
2359                      TREE_OPERAND (expr, 0));
2360             return truthvalue_true_node;
2361           }
2362
2363         /* If we are taking the address of an external decl, it might be
2364            zero if it is weak, so we cannot optimize.  */
2365         if (DECL_P (TREE_OPERAND (expr, 0))
2366             && DECL_EXTERNAL (TREE_OPERAND (expr, 0)))
2367           break;
2368
2369         if (TREE_SIDE_EFFECTS (TREE_OPERAND (expr, 0)))
2370           return build2 (COMPOUND_EXPR, truthvalue_type_node,
2371                          TREE_OPERAND (expr, 0), truthvalue_true_node);
2372         else
2373           return truthvalue_true_node;
2374       }
2375
2376     case COMPLEX_EXPR:
2377       return build_binary_op ((TREE_SIDE_EFFECTS (TREE_OPERAND (expr, 1))
2378                                ? TRUTH_OR_EXPR : TRUTH_ORIF_EXPR),
2379                 lang_hooks.truthvalue_conversion (TREE_OPERAND (expr, 0)),
2380                 lang_hooks.truthvalue_conversion (TREE_OPERAND (expr, 1)),
2381                               0);
2382
2383     case NEGATE_EXPR:
2384     case ABS_EXPR:
2385     case FLOAT_EXPR:
2386       /* These don't change whether an object is nonzero or zero.  */
2387       return lang_hooks.truthvalue_conversion (TREE_OPERAND (expr, 0));
2388
2389     case LROTATE_EXPR:
2390     case RROTATE_EXPR:
2391       /* These don't change whether an object is zero or nonzero, but
2392          we can't ignore them if their second arg has side-effects.  */
2393       if (TREE_SIDE_EFFECTS (TREE_OPERAND (expr, 1)))
2394         return build2 (COMPOUND_EXPR, truthvalue_type_node,
2395                        TREE_OPERAND (expr, 1),
2396                        lang_hooks.truthvalue_conversion (TREE_OPERAND (expr, 0)));
2397       else
2398         return lang_hooks.truthvalue_conversion (TREE_OPERAND (expr, 0));
2399
2400     case COND_EXPR:
2401       /* Distribute the conversion into the arms of a COND_EXPR.  */
2402       return fold (build3 (COND_EXPR, truthvalue_type_node,
2403                 TREE_OPERAND (expr, 0),
2404                 lang_hooks.truthvalue_conversion (TREE_OPERAND (expr, 1)),
2405                 lang_hooks.truthvalue_conversion (TREE_OPERAND (expr, 2))));
2406
2407     case CONVERT_EXPR:
2408       /* Don't cancel the effect of a CONVERT_EXPR from a REFERENCE_TYPE,
2409          since that affects how `default_conversion' will behave.  */
2410       if (TREE_CODE (TREE_TYPE (expr)) == REFERENCE_TYPE
2411           || TREE_CODE (TREE_TYPE (TREE_OPERAND (expr, 0))) == REFERENCE_TYPE)
2412         break;
2413       /* Fall through....  */
2414     case NOP_EXPR:
2415       /* If this is widening the argument, we can ignore it.  */
2416       if (TYPE_PRECISION (TREE_TYPE (expr))
2417           >= TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (expr, 0))))
2418         return lang_hooks.truthvalue_conversion (TREE_OPERAND (expr, 0));
2419       break;
2420
2421     case MINUS_EXPR:
2422       /* Perhaps reduce (x - y) != 0 to (x != y).  The expressions
2423          aren't guaranteed to the be same for modes that can represent
2424          infinity, since if x and y are both +infinity, or both
2425          -infinity, then x - y is not a number.
2426
2427          Note that this transformation is safe when x or y is NaN.
2428          (x - y) is then NaN, and both (x - y) != 0 and x != y will
2429          be false.  */
2430       if (HONOR_INFINITIES (TYPE_MODE (TREE_TYPE (TREE_OPERAND (expr, 0)))))
2431         break;
2432       /* Fall through....  */
2433     case BIT_XOR_EXPR:
2434       /* This and MINUS_EXPR can be changed into a comparison of the
2435          two objects.  */
2436       if (TREE_TYPE (TREE_OPERAND (expr, 0))
2437           == TREE_TYPE (TREE_OPERAND (expr, 1)))
2438         return build_binary_op (NE_EXPR, TREE_OPERAND (expr, 0),
2439                                 TREE_OPERAND (expr, 1), 1);
2440       return build_binary_op (NE_EXPR, TREE_OPERAND (expr, 0),
2441                               fold (build1 (NOP_EXPR,
2442                                             TREE_TYPE (TREE_OPERAND (expr, 0)),
2443                                             TREE_OPERAND (expr, 1))), 1);
2444
2445     case BIT_AND_EXPR:
2446       if (integer_onep (TREE_OPERAND (expr, 1))
2447           && TREE_TYPE (expr) != truthvalue_type_node)
2448         /* Using convert here would cause infinite recursion.  */
2449         return build1 (NOP_EXPR, truthvalue_type_node, expr);
2450       break;
2451
2452     case MODIFY_EXPR:
2453       if (warn_parentheses && !TREE_NO_WARNING (expr))
2454         warning ("suggest parentheses around assignment used as truth value");
2455       break;
2456
2457     default:
2458       break;
2459     }
2460
2461   if (TREE_CODE (TREE_TYPE (expr)) == COMPLEX_TYPE)
2462     {
2463       tree t = save_expr (expr);
2464       return (build_binary_op
2465               ((TREE_SIDE_EFFECTS (expr)
2466                 ? TRUTH_OR_EXPR : TRUTH_ORIF_EXPR),
2467         lang_hooks.truthvalue_conversion (build_unary_op (REALPART_EXPR, t, 0)),
2468         lang_hooks.truthvalue_conversion (build_unary_op (IMAGPART_EXPR, t, 0)),
2469                0));
2470     }
2471
2472   return build_binary_op (NE_EXPR, expr, integer_zero_node, 1);
2473 }
2474 \f
2475 static tree builtin_function_2 (const char *builtin_name, const char *name,
2476                                 tree builtin_type, tree type,
2477                                 enum built_in_function function_code,
2478                                 enum built_in_class cl, int library_name_p,
2479                                 bool nonansi_p,
2480                                 tree attrs);
2481
2482 /* Make a variant type in the proper way for C/C++, propagating qualifiers
2483    down to the element type of an array.  */
2484
2485 tree
2486 c_build_qualified_type (tree type, int type_quals)
2487 {
2488   if (type == error_mark_node)
2489     return type;
2490
2491   if (TREE_CODE (type) == ARRAY_TYPE)
2492     return build_array_type (c_build_qualified_type (TREE_TYPE (type),
2493                                                      type_quals),
2494                              TYPE_DOMAIN (type));
2495
2496   /* A restrict-qualified pointer type must be a pointer to object or
2497      incomplete type.  Note that the use of POINTER_TYPE_P also allows
2498      REFERENCE_TYPEs, which is appropriate for C++.  */
2499   if ((type_quals & TYPE_QUAL_RESTRICT)
2500       && (!POINTER_TYPE_P (type)
2501           || !C_TYPE_OBJECT_OR_INCOMPLETE_P (TREE_TYPE (type))))
2502     {
2503       error ("invalid use of %<restrict%>");
2504       type_quals &= ~TYPE_QUAL_RESTRICT;
2505     }
2506
2507   return build_qualified_type (type, type_quals);
2508 }
2509
2510 /* Apply the TYPE_QUALS to the new DECL.  */
2511
2512 void
2513 c_apply_type_quals_to_decl (int type_quals, tree decl)
2514 {
2515   tree type = TREE_TYPE (decl);
2516
2517   if (type == error_mark_node)
2518     return;
2519
2520   if (((type_quals & TYPE_QUAL_CONST)
2521        || (type && TREE_CODE (type) == REFERENCE_TYPE))
2522       /* An object declared 'const' is only readonly after it is
2523          initialized.  We don't have any way of expressing this currently,
2524          so we need to be conservative and unset TREE_READONLY for types
2525          with constructors.  Otherwise aliasing code will ignore stores in
2526          an inline constructor.  */
2527       && !(type && TYPE_NEEDS_CONSTRUCTING (type)))
2528     TREE_READONLY (decl) = 1;
2529   if (type_quals & TYPE_QUAL_VOLATILE)
2530     {
2531       TREE_SIDE_EFFECTS (decl) = 1;
2532       TREE_THIS_VOLATILE (decl) = 1;
2533     }
2534   if (type_quals & TYPE_QUAL_RESTRICT)
2535     {
2536       while (type && TREE_CODE (type) == ARRAY_TYPE)
2537         /* Allow 'restrict' on arrays of pointers.
2538            FIXME currently we just ignore it.  */
2539         type = TREE_TYPE (type);
2540       if (!type
2541           || !POINTER_TYPE_P (type)
2542           || !C_TYPE_OBJECT_OR_INCOMPLETE_P (TREE_TYPE (type)))
2543         error ("invalid use of %<restrict%>");
2544       else if (flag_strict_aliasing && type == TREE_TYPE (decl))
2545         /* Indicate we need to make a unique alias set for this pointer.
2546            We can't do it here because it might be pointing to an
2547            incomplete type.  */
2548         DECL_POINTER_ALIAS_SET (decl) = -2;
2549     }
2550 }
2551
2552 /* Hash function for the problem of multiple type definitions in
2553    different files.  This must hash all types that will compare
2554    equal via comptypes to the same value.  In practice it hashes
2555    on some of the simple stuff and leaves the details to comptypes.  */
2556
2557 static hashval_t
2558 c_type_hash (const void *p)
2559 {
2560   int i = 0;
2561   int shift, size;
2562   tree t = (tree)p;
2563   tree t2;
2564   switch (TREE_CODE (t))
2565     {
2566     /* For pointers, hash on pointee type plus some swizzling.  */
2567     case POINTER_TYPE:
2568       return c_type_hash (TREE_TYPE (t)) ^ 0x3003003;
2569     /* Hash on number of elements and total size.  */
2570     case ENUMERAL_TYPE:
2571       shift = 3;
2572       t2 = TYPE_VALUES (t);
2573       break;
2574     case RECORD_TYPE:
2575       shift = 0;
2576       t2 = TYPE_FIELDS (t);
2577       break;
2578     case QUAL_UNION_TYPE:
2579       shift = 1;
2580       t2 = TYPE_FIELDS (t);
2581       break;
2582     case UNION_TYPE:
2583       shift = 2;
2584       t2 = TYPE_FIELDS (t);
2585       break;
2586     default:
2587       gcc_unreachable ();
2588     }
2589   for (; t2; t2 = TREE_CHAIN (t2))
2590     i++;
2591   size = TREE_INT_CST_LOW (TYPE_SIZE (t));
2592   return ((size << 24) | (i << shift));
2593 }
2594
2595 /* Return the typed-based alias set for T, which may be an expression
2596    or a type.  Return -1 if we don't do anything special.  */
2597
2598 HOST_WIDE_INT
2599 c_common_get_alias_set (tree t)
2600 {
2601   tree u;
2602   PTR *slot;
2603   static htab_t type_hash_table;
2604
2605   /* Permit type-punning when accessing a union, provided the access
2606      is directly through the union.  For example, this code does not
2607      permit taking the address of a union member and then storing
2608      through it.  Even the type-punning allowed here is a GCC
2609      extension, albeit a common and useful one; the C standard says
2610      that such accesses have implementation-defined behavior.  */
2611   for (u = t;
2612        TREE_CODE (u) == COMPONENT_REF || TREE_CODE (u) == ARRAY_REF;
2613        u = TREE_OPERAND (u, 0))
2614     if (TREE_CODE (u) == COMPONENT_REF
2615         && TREE_CODE (TREE_TYPE (TREE_OPERAND (u, 0))) == UNION_TYPE)
2616       return 0;
2617
2618   /* That's all the expressions we handle specially.  */
2619   if (! TYPE_P (t))
2620     return -1;
2621
2622   /* The C standard guarantees that any object may be accessed via an
2623      lvalue that has character type.  */
2624   if (t == char_type_node
2625       || t == signed_char_type_node
2626       || t == unsigned_char_type_node)
2627     return 0;
2628
2629   /* If it has the may_alias attribute, it can alias anything.  */
2630   if (lookup_attribute ("may_alias", TYPE_ATTRIBUTES (t)))
2631     return 0;
2632
2633   /* The C standard specifically allows aliasing between signed and
2634      unsigned variants of the same type.  We treat the signed
2635      variant as canonical.  */
2636   if (TREE_CODE (t) == INTEGER_TYPE && TYPE_UNSIGNED (t))
2637     {
2638       tree t1 = c_common_signed_type (t);
2639
2640       /* t1 == t can happen for boolean nodes which are always unsigned.  */
2641       if (t1 != t)
2642         return get_alias_set (t1);
2643     }
2644   else if (POINTER_TYPE_P (t))
2645     {
2646       tree t1;
2647
2648       /* Unfortunately, there is no canonical form of a pointer type.
2649          In particular, if we have `typedef int I', then `int *', and
2650          `I *' are different types.  So, we have to pick a canonical
2651          representative.  We do this below.
2652
2653          Technically, this approach is actually more conservative that
2654          it needs to be.  In particular, `const int *' and `int *'
2655          should be in different alias sets, according to the C and C++
2656          standard, since their types are not the same, and so,
2657          technically, an `int **' and `const int **' cannot point at
2658          the same thing.
2659
2660          But, the standard is wrong.  In particular, this code is
2661          legal C++:
2662
2663             int *ip;
2664             int **ipp = &ip;
2665             const int* const* cipp = ipp;
2666
2667          And, it doesn't make sense for that to be legal unless you
2668          can dereference IPP and CIPP.  So, we ignore cv-qualifiers on
2669          the pointed-to types.  This issue has been reported to the
2670          C++ committee.  */
2671       t1 = build_type_no_quals (t);
2672       if (t1 != t)
2673         return get_alias_set (t1);
2674     }
2675
2676   /* Handle the case of multiple type nodes referring to "the same" type,
2677      which occurs with IMA.  These share an alias set.  FIXME:  Currently only
2678      C90 is handled.  (In C99 type compatibility is not transitive, which
2679      complicates things mightily. The alias set splay trees can theoretically
2680      represent this, but insertion is tricky when you consider all the
2681      different orders things might arrive in.) */
2682
2683   if (c_language != clk_c || flag_isoc99)
2684     return -1;
2685
2686   /* Save time if there's only one input file.  */
2687   if (num_in_fnames == 1)
2688     return -1;
2689
2690   /* Pointers need special handling if they point to any type that
2691      needs special handling (below).  */
2692   if (TREE_CODE (t) == POINTER_TYPE)
2693     {
2694       tree t2;
2695       /* Find bottom type under any nested POINTERs.  */
2696       for (t2 = TREE_TYPE (t);
2697      TREE_CODE (t2) == POINTER_TYPE;
2698      t2 = TREE_TYPE (t2))
2699   ;
2700       if (TREE_CODE (t2) != RECORD_TYPE
2701     && TREE_CODE (t2) != ENUMERAL_TYPE
2702     && TREE_CODE (t2) != QUAL_UNION_TYPE
2703     && TREE_CODE (t2) != UNION_TYPE)
2704   return -1;
2705       if (TYPE_SIZE (t2) == 0)
2706   return -1;
2707     }
2708   /* These are the only cases that need special handling.  */
2709   if (TREE_CODE (t) != RECORD_TYPE
2710       && TREE_CODE (t) != ENUMERAL_TYPE
2711       && TREE_CODE (t) != QUAL_UNION_TYPE
2712       && TREE_CODE (t) != UNION_TYPE
2713       && TREE_CODE (t) != POINTER_TYPE)
2714     return -1;
2715   /* Undefined? */
2716   if (TYPE_SIZE (t) == 0)
2717     return -1;
2718
2719   /* Look up t in hash table.  Only one of the compatible types within each
2720      alias set is recorded in the table.  */
2721   if (!type_hash_table)
2722     type_hash_table = htab_create (1021, c_type_hash,
2723             (htab_eq) lang_hooks.types_compatible_p,
2724             NULL);
2725   slot = htab_find_slot (type_hash_table, t, INSERT);
2726   if (*slot != NULL)
2727     {
2728       TYPE_ALIAS_SET (t) = TYPE_ALIAS_SET ((tree)*slot);
2729       return TYPE_ALIAS_SET ((tree)*slot);
2730     }
2731   else
2732     /* Our caller will assign and record (in t) a new alias set; all we need
2733        to do is remember t in the hash table.  */
2734     *slot = t;
2735
2736   return -1;
2737 }
2738 \f
2739 /* Compute the value of 'sizeof (TYPE)' or '__alignof__ (TYPE)', where the
2740    second parameter indicates which OPERATOR is being applied.  The COMPLAIN
2741    flag controls whether we should diagnose possibly ill-formed
2742    constructs or not.  */
2743 tree
2744 c_sizeof_or_alignof_type (tree type, enum tree_code op, int complain)
2745 {
2746   const char *op_name;
2747   tree value = NULL;
2748   enum tree_code type_code = TREE_CODE (type);
2749
2750   gcc_assert (op == SIZEOF_EXPR || op == ALIGNOF_EXPR);
2751   op_name = op == SIZEOF_EXPR ? "sizeof" : "__alignof__";
2752
2753   if (type_code == FUNCTION_TYPE)
2754     {
2755       if (op == SIZEOF_EXPR)
2756         {
2757           if (complain && (pedantic || warn_pointer_arith))
2758             pedwarn ("invalid application of %<sizeof%> to a function type");
2759           value = size_one_node;
2760         }
2761       else
2762         value = size_int (FUNCTION_BOUNDARY / BITS_PER_UNIT);
2763     }
2764   else if (type_code == VOID_TYPE || type_code == ERROR_MARK)
2765     {
2766       if (type_code == VOID_TYPE
2767           && complain && (pedantic || warn_pointer_arith))
2768         pedwarn ("invalid application of %qs to a void type", op_name);
2769       value = size_one_node;
2770     }
2771   else if (!COMPLETE_TYPE_P (type))
2772     {
2773       if (complain)
2774         error ("invalid application of %qs to incomplete type %qT ",
2775                op_name, type);
2776       value = size_zero_node;
2777     }
2778   else
2779     {
2780       if (op == (enum tree_code) SIZEOF_EXPR)
2781         /* Convert in case a char is more than one unit.  */
2782         value = size_binop (CEIL_DIV_EXPR, TYPE_SIZE_UNIT (type),
2783                             size_int (TYPE_PRECISION (char_type_node)
2784                                       / BITS_PER_UNIT));
2785       else
2786         value = size_int (TYPE_ALIGN_UNIT (type));
2787     }
2788
2789   /* VALUE will have an integer type with TYPE_IS_SIZETYPE set.
2790      TYPE_IS_SIZETYPE means that certain things (like overflow) will
2791      never happen.  However, this node should really have type
2792      `size_t', which is just a typedef for an ordinary integer type.  */
2793   value = fold (build1 (NOP_EXPR, size_type_node, value));
2794   gcc_assert (!TYPE_IS_SIZETYPE (TREE_TYPE (value)));
2795
2796   return value;
2797 }
2798
2799 /* Implement the __alignof keyword: Return the minimum required
2800    alignment of EXPR, measured in bytes.  For VAR_DECL's and
2801    FIELD_DECL's return DECL_ALIGN (which can be set from an
2802    "aligned" __attribute__ specification).  */
2803
2804 tree
2805 c_alignof_expr (tree expr)
2806 {
2807   tree t;
2808
2809   if (TREE_CODE (expr) == VAR_DECL)
2810     t = size_int (DECL_ALIGN_UNIT (expr));
2811
2812   else if (TREE_CODE (expr) == COMPONENT_REF
2813            && DECL_C_BIT_FIELD (TREE_OPERAND (expr, 1)))
2814     {
2815       error ("%<__alignof%> applied to a bit-field");
2816       t = size_one_node;
2817     }
2818   else if (TREE_CODE (expr) == COMPONENT_REF
2819            && TREE_CODE (TREE_OPERAND (expr, 1)) == FIELD_DECL)
2820     t = size_int (DECL_ALIGN_UNIT (TREE_OPERAND (expr, 1)));
2821
2822   else if (TREE_CODE (expr) == INDIRECT_REF)
2823     {
2824       tree t = TREE_OPERAND (expr, 0);
2825       tree best = t;
2826       int bestalign = TYPE_ALIGN (TREE_TYPE (TREE_TYPE (t)));
2827
2828       while (TREE_CODE (t) == NOP_EXPR
2829              && TREE_CODE (TREE_TYPE (TREE_OPERAND (t, 0))) == POINTER_TYPE)
2830         {
2831           int thisalign;
2832
2833           t = TREE_OPERAND (t, 0);
2834           thisalign = TYPE_ALIGN (TREE_TYPE (TREE_TYPE (t)));
2835           if (thisalign > bestalign)
2836             best = t, bestalign = thisalign;
2837         }
2838       return c_alignof (TREE_TYPE (TREE_TYPE (best)));
2839     }
2840   else
2841     return c_alignof (TREE_TYPE (expr));
2842
2843   return fold (build1 (NOP_EXPR, size_type_node, t));
2844 }
2845 \f
2846 /* Handle C and C++ default attributes.  */
2847
2848 enum built_in_attribute
2849 {
2850 #define DEF_ATTR_NULL_TREE(ENUM) ENUM,
2851 #define DEF_ATTR_INT(ENUM, VALUE) ENUM,
2852 #define DEF_ATTR_IDENT(ENUM, STRING) ENUM,
2853 #define DEF_ATTR_TREE_LIST(ENUM, PURPOSE, VALUE, CHAIN) ENUM,
2854 #include "builtin-attrs.def"
2855 #undef DEF_ATTR_NULL_TREE
2856 #undef DEF_ATTR_INT
2857 #undef DEF_ATTR_IDENT
2858 #undef DEF_ATTR_TREE_LIST
2859   ATTR_LAST
2860 };
2861
2862 static GTY(()) tree built_in_attributes[(int) ATTR_LAST];
2863
2864 static void c_init_attributes (void);
2865
2866 /* Build tree nodes and builtin functions common to both C and C++ language
2867    frontends.  */
2868
2869 void
2870 c_common_nodes_and_builtins (void)
2871 {
2872   enum builtin_type
2873   {
2874 #define DEF_PRIMITIVE_TYPE(NAME, VALUE) NAME,
2875 #define DEF_FUNCTION_TYPE_0(NAME, RETURN) NAME,
2876 #define DEF_FUNCTION_TYPE_1(NAME, RETURN, ARG1) NAME,
2877 #define DEF_FUNCTION_TYPE_2(NAME, RETURN, ARG1, ARG2) NAME,
2878 #define DEF_FUNCTION_TYPE_3(NAME, RETURN, ARG1, ARG2, ARG3) NAME,
2879 #define DEF_FUNCTION_TYPE_4(NAME, RETURN, ARG1, ARG2, ARG3, ARG4) NAME,
2880 #define DEF_FUNCTION_TYPE_VAR_0(NAME, RETURN) NAME,
2881 #define DEF_FUNCTION_TYPE_VAR_1(NAME, RETURN, ARG1) NAME,
2882 #define DEF_FUNCTION_TYPE_VAR_2(NAME, RETURN, ARG1, ARG2) NAME,
2883 #define DEF_FUNCTION_TYPE_VAR_3(NAME, RETURN, ARG1, ARG2, ARG3) NAME,
2884 #define DEF_POINTER_TYPE(NAME, TYPE) NAME,
2885 #include "builtin-types.def"
2886 #undef DEF_PRIMITIVE_TYPE
2887 #undef DEF_FUNCTION_TYPE_0
2888 #undef DEF_FUNCTION_TYPE_1
2889 #undef DEF_FUNCTION_TYPE_2
2890 #undef DEF_FUNCTION_TYPE_3
2891 #undef DEF_FUNCTION_TYPE_4
2892 #undef DEF_FUNCTION_TYPE_VAR_0
2893 #undef DEF_FUNCTION_TYPE_VAR_1
2894 #undef DEF_FUNCTION_TYPE_VAR_2
2895 #undef DEF_FUNCTION_TYPE_VAR_3
2896 #undef DEF_POINTER_TYPE
2897     BT_LAST
2898   };
2899
2900   typedef enum builtin_type builtin_type;
2901
2902   tree builtin_types[(int) BT_LAST];
2903   int wchar_type_size;
2904   tree array_domain_type;
2905   tree va_list_ref_type_node;
2906   tree va_list_arg_type_node;
2907
2908   /* Define `int' and `char' first so that dbx will output them first.  */
2909   record_builtin_type (RID_INT, NULL, integer_type_node);
2910   record_builtin_type (RID_CHAR, "char", char_type_node);
2911
2912   /* `signed' is the same as `int'.  FIXME: the declarations of "signed",
2913      "unsigned long", "long long unsigned" and "unsigned short" were in C++
2914      but not C.  Are the conditionals here needed?  */
2915   if (c_dialect_cxx ())
2916     record_builtin_type (RID_SIGNED, NULL, integer_type_node);
2917   record_builtin_type (RID_LONG, "long int", long_integer_type_node);
2918   record_builtin_type (RID_UNSIGNED, "unsigned int", unsigned_type_node);
2919   record_builtin_type (RID_MAX, "long unsigned int",
2920                        long_unsigned_type_node);
2921   if (c_dialect_cxx ())
2922     record_builtin_type (RID_MAX, "unsigned long", long_unsigned_type_node);
2923   record_builtin_type (RID_MAX, "long long int",
2924                        long_long_integer_type_node);
2925   record_builtin_type (RID_MAX, "long long unsigned int",
2926                        long_long_unsigned_type_node);
2927   if (c_dialect_cxx ())
2928     record_builtin_type (RID_MAX, "long long unsigned",
2929                          long_long_unsigned_type_node);
2930   record_builtin_type (RID_SHORT, "short int", short_integer_type_node);
2931   record_builtin_type (RID_MAX, "short unsigned int",
2932                        short_unsigned_type_node);
2933   if (c_dialect_cxx ())
2934     record_builtin_type (RID_MAX, "unsigned short",
2935                          short_unsigned_type_node);
2936
2937   /* Define both `signed char' and `unsigned char'.  */
2938   record_builtin_type (RID_MAX, "signed char", signed_char_type_node);
2939   record_builtin_type (RID_MAX, "unsigned char", unsigned_char_type_node);
2940
2941   /* These are types that c_common_type_for_size and
2942      c_common_type_for_mode use.  */
2943   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
2944                                          intQI_type_node));
2945   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
2946                                          intHI_type_node));
2947   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
2948                                          intSI_type_node));
2949   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
2950                                          intDI_type_node));
2951 #if HOST_BITS_PER_WIDE_INT >= 64
2952   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL,
2953                                          get_identifier ("__int128_t"),
2954                                          intTI_type_node));
2955 #endif
2956   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
2957                                          unsigned_intQI_type_node));
2958   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
2959                                          unsigned_intHI_type_node));
2960   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
2961                                          unsigned_intSI_type_node));
2962   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
2963                                          unsigned_intDI_type_node));
2964 #if HOST_BITS_PER_WIDE_INT >= 64
2965   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL,
2966                                          get_identifier ("__uint128_t"),
2967                                          unsigned_intTI_type_node));
2968 #endif
2969
2970   /* Create the widest literal types.  */
2971   widest_integer_literal_type_node
2972     = make_signed_type (HOST_BITS_PER_WIDE_INT * 2);
2973   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
2974                                          widest_integer_literal_type_node));
2975
2976   widest_unsigned_literal_type_node
2977     = make_unsigned_type (HOST_BITS_PER_WIDE_INT * 2);
2978   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
2979                                          widest_unsigned_literal_type_node));
2980
2981   /* `unsigned long' is the standard type for sizeof.
2982      Note that stddef.h uses `unsigned long',
2983      and this must agree, even if long and int are the same size.  */
2984   size_type_node =
2985     TREE_TYPE (identifier_global_value (get_identifier (SIZE_TYPE)));
2986   signed_size_type_node = c_common_signed_type (size_type_node);
2987   set_sizetype (size_type_node);
2988
2989   pid_type_node =
2990     TREE_TYPE (identifier_global_value (get_identifier (PID_TYPE)));
2991
2992   build_common_tree_nodes_2 (flag_short_double);
2993
2994   record_builtin_type (RID_FLOAT, NULL, float_type_node);
2995   record_builtin_type (RID_DOUBLE, NULL, double_type_node);
2996   record_builtin_type (RID_MAX, "long double", long_double_type_node);
2997
2998   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL,
2999                                          get_identifier ("complex int"),
3000                                          complex_integer_type_node));
3001   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL,
3002                                          get_identifier ("complex float"),
3003                                          complex_float_type_node));
3004   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL,
3005                                          get_identifier ("complex double"),
3006                                          complex_double_type_node));
3007   lang_hooks.decls.pushdecl
3008     (build_decl (TYPE_DECL, get_identifier ("complex long double"),
3009                  complex_long_double_type_node));
3010
3011   if (c_dialect_cxx ())
3012     /* For C++, make fileptr_type_node a distinct void * type until
3013        FILE type is defined.  */
3014     fileptr_type_node = build_variant_type_copy (ptr_type_node);
3015
3016   record_builtin_type (RID_VOID, NULL, void_type_node);
3017
3018   /* This node must not be shared.  */
3019   void_zero_node = make_node (INTEGER_CST);
3020   TREE_TYPE (void_zero_node) = void_type_node;
3021
3022   void_list_node = build_void_list_node ();
3023
3024   /* Make a type to be the domain of a few array types
3025      whose domains don't really matter.
3026      200 is small enough that it always fits in size_t
3027      and large enough that it can hold most function names for the
3028      initializations of __FUNCTION__ and __PRETTY_FUNCTION__.  */
3029   array_domain_type = build_index_type (size_int (200));
3030
3031   /* Make a type for arrays of characters.
3032      With luck nothing will ever really depend on the length of this
3033      array type.  */
3034   char_array_type_node
3035     = build_array_type (char_type_node, array_domain_type);
3036
3037   /* Likewise for arrays of ints.  */
3038   int_array_type_node
3039     = build_array_type (integer_type_node, array_domain_type);
3040
3041   string_type_node = build_pointer_type (char_type_node);
3042   const_string_type_node
3043     = build_pointer_type (build_qualified_type
3044                           (char_type_node, TYPE_QUAL_CONST));
3045
3046   /* This is special for C++ so functions can be overloaded.  */
3047   wchar_type_node = get_identifier (MODIFIED_WCHAR_TYPE);
3048   wchar_type_node = TREE_TYPE (identifier_global_value (wchar_type_node));
3049   wchar_type_size = TYPE_PRECISION (wchar_type_node);
3050   if (c_dialect_cxx ())
3051     {
3052       if (TYPE_UNSIGNED (wchar_type_node))
3053         wchar_type_node = make_unsigned_type (wchar_type_size);
3054       else
3055         wchar_type_node = make_signed_type (wchar_type_size);
3056       record_builtin_type (RID_WCHAR, "wchar_t", wchar_type_node);
3057     }
3058   else
3059     {
3060       signed_wchar_type_node = c_common_signed_type (wchar_type_node);
3061       unsigned_wchar_type_node = c_common_unsigned_type (wchar_type_node);
3062     }
3063
3064   /* This is for wide string constants.  */
3065   wchar_array_type_node
3066     = build_array_type (wchar_type_node, array_domain_type);
3067
3068   wint_type_node =
3069     TREE_TYPE (identifier_global_value (get_identifier (WINT_TYPE)));
3070
3071   intmax_type_node =
3072     TREE_TYPE (identifier_global_value (get_identifier (INTMAX_TYPE)));
3073   uintmax_type_node =
3074     TREE_TYPE (identifier_global_value (get_identifier (UINTMAX_TYPE)));
3075
3076   default_function_type = build_function_type (integer_type_node, NULL_TREE);
3077   ptrdiff_type_node
3078     = TREE_TYPE (identifier_global_value (get_identifier (PTRDIFF_TYPE)));
3079   unsigned_ptrdiff_type_node = c_common_unsigned_type (ptrdiff_type_node);
3080
3081   lang_hooks.decls.pushdecl
3082     (build_decl (TYPE_DECL, get_identifier ("__builtin_va_list"),
3083                  va_list_type_node));
3084
3085   if (TREE_CODE (va_list_type_node) == ARRAY_TYPE)
3086     {
3087       va_list_arg_type_node = va_list_ref_type_node =
3088         build_pointer_type (TREE_TYPE (va_list_type_node));
3089     }
3090   else
3091     {
3092       va_list_arg_type_node = va_list_type_node;
3093       va_list_ref_type_node = build_reference_type (va_list_type_node);
3094     }
3095
3096 #define DEF_PRIMITIVE_TYPE(ENUM, VALUE) \
3097   builtin_types[(int) ENUM] = VALUE;
3098 #define DEF_FUNCTION_TYPE_0(ENUM, RETURN)               \
3099   builtin_types[(int) ENUM]                             \
3100     = build_function_type (builtin_types[(int) RETURN], \
3101                            void_list_node);
3102 #define DEF_FUNCTION_TYPE_1(ENUM, RETURN, ARG1)                         \
3103   builtin_types[(int) ENUM]                                             \
3104     = build_function_type (builtin_types[(int) RETURN],                 \
3105                            tree_cons (NULL_TREE,                        \
3106                                       builtin_types[(int) ARG1],        \
3107                                       void_list_node));
3108 #define DEF_FUNCTION_TYPE_2(ENUM, RETURN, ARG1, ARG2)   \
3109   builtin_types[(int) ENUM]                             \
3110     = build_function_type                               \
3111       (builtin_types[(int) RETURN],                     \
3112        tree_cons (NULL_TREE,                            \
3113                   builtin_types[(int) ARG1],            \
3114                   tree_cons (NULL_TREE,                 \
3115                              builtin_types[(int) ARG2], \
3116                              void_list_node)));
3117 #define DEF_FUNCTION_TYPE_3(ENUM, RETURN, ARG1, ARG2, ARG3)              \
3118   builtin_types[(int) ENUM]                                              \
3119     = build_function_type                                                \
3120       (builtin_types[(int) RETURN],                                      \
3121        tree_cons (NULL_TREE,                                             \
3122                   builtin_types[(int) ARG1],                             \
3123                   tree_cons (NULL_TREE,                                  \
3124                              builtin_types[(int) ARG2],                  \
3125                              tree_cons (NULL_TREE,                       \
3126                                         builtin_types[(int) ARG3],       \
3127                                         void_list_node))));
3128 #define DEF_FUNCTION_TYPE_4(ENUM, RETURN, ARG1, ARG2, ARG3, ARG4)       \
3129   builtin_types[(int) ENUM]                                             \
3130     = build_function_type                                               \
3131       (builtin_types[(int) RETURN],                                     \
3132        tree_cons (NULL_TREE,                                            \
3133                   builtin_types[(int) ARG1],                            \
3134                   tree_cons (NULL_TREE,                                 \
3135                              builtin_types[(int) ARG2],                 \
3136                              tree_cons                                  \
3137                              (NULL_TREE,                                \
3138                               builtin_types[(int) ARG3],                \
3139                               tree_cons (NULL_TREE,                     \
3140                                          builtin_types[(int) ARG4],     \
3141                                          void_list_node)))));
3142 #define DEF_FUNCTION_TYPE_VAR_0(ENUM, RETURN)                           \
3143   builtin_types[(int) ENUM]                                             \
3144     = build_function_type (builtin_types[(int) RETURN], NULL_TREE);
3145 #define DEF_FUNCTION_TYPE_VAR_1(ENUM, RETURN, ARG1)                      \
3146    builtin_types[(int) ENUM]                                             \
3147     = build_function_type (builtin_types[(int) RETURN],          \
3148                            tree_cons (NULL_TREE,                         \
3149                                       builtin_types[(int) ARG1],         \
3150                                       NULL_TREE));
3151
3152 #define DEF_FUNCTION_TYPE_VAR_2(ENUM, RETURN, ARG1, ARG2)       \
3153    builtin_types[(int) ENUM]                                    \
3154     = build_function_type                                       \
3155       (builtin_types[(int) RETURN],                             \
3156        tree_cons (NULL_TREE,                                    \
3157                   builtin_types[(int) ARG1],                    \
3158                   tree_cons (NULL_TREE,                         \
3159                              builtin_types[(int) ARG2],         \
3160                              NULL_TREE)));
3161
3162 #define DEF_FUNCTION_TYPE_VAR_3(ENUM, RETURN, ARG1, ARG2, ARG3)         \
3163    builtin_types[(int) ENUM]                                            \
3164     = build_function_type                                               \
3165       (builtin_types[(int) RETURN],                                     \
3166        tree_cons (NULL_TREE,                                            \
3167                   builtin_types[(int) ARG1],                            \
3168                   tree_cons (NULL_TREE,                                 \
3169                              builtin_types[(int) ARG2],                 \
3170                              tree_cons (NULL_TREE,                      \
3171                                         builtin_types[(int) ARG3],      \
3172                                         NULL_TREE))));
3173
3174 #define DEF_POINTER_TYPE(ENUM, TYPE)                    \
3175   builtin_types[(int) ENUM]                             \
3176     = build_pointer_type (builtin_types[(int) TYPE]);
3177 #include "builtin-types.def"
3178 #undef DEF_PRIMITIVE_TYPE
3179 #undef DEF_FUNCTION_TYPE_1
3180 #undef DEF_FUNCTION_TYPE_2
3181 #undef DEF_FUNCTION_TYPE_3
3182 #undef DEF_FUNCTION_TYPE_4
3183 #undef DEF_FUNCTION_TYPE_VAR_0
3184 #undef DEF_FUNCTION_TYPE_VAR_1
3185 #undef DEF_FUNCTION_TYPE_VAR_2
3186 #undef DEF_FUNCTION_TYPE_VAR_3
3187 #undef DEF_POINTER_TYPE
3188
3189   c_init_attributes ();
3190
3191 #define DEF_BUILTIN(ENUM, NAME, CLASS, TYPE, LIBTYPE,                   \
3192                     BOTH_P, FALLBACK_P, NONANSI_P, ATTRS, IMPLICIT)     \
3193   if (NAME)                                                             \
3194     {                                                                   \
3195       tree decl;                                                        \
3196                                                                         \
3197       gcc_assert (!strncmp (NAME, "__builtin_",                         \
3198                             strlen ("__builtin_")));                    \
3199                                                                         \
3200       if (!BOTH_P)                                                      \
3201         decl = lang_hooks.builtin_function (NAME, builtin_types[TYPE],  \
3202                                  ENUM,                                  \
3203                                  CLASS,                                 \
3204                                  (FALLBACK_P                            \
3205                                   ? (NAME + strlen ("__builtin_"))      \
3206                                   : NULL),                              \
3207                                  built_in_attributes[(int) ATTRS]);     \
3208       else                                                              \
3209         decl = builtin_function_2 (NAME,                                \
3210                                    NAME + strlen ("__builtin_"),        \
3211                                    builtin_types[TYPE],                 \
3212                                    builtin_types[LIBTYPE],              \
3213                                    ENUM,                                \
3214                                    CLASS,                               \
3215                                    FALLBACK_P,                          \
3216                                    NONANSI_P,                           \
3217                                    built_in_attributes[(int) ATTRS]);   \
3218                                                                         \
3219       built_in_decls[(int) ENUM] = decl;                                \
3220       if (IMPLICIT)                                                     \
3221         implicit_built_in_decls[(int) ENUM] = decl;                     \
3222     }
3223 #include "builtins.def"
3224 #undef DEF_BUILTIN
3225
3226   targetm.init_builtins ();
3227   if (flag_mudflap)
3228     mudflap_init ();
3229
3230   main_identifier_node = get_identifier ("main");
3231 }
3232
3233 tree
3234 build_va_arg (tree expr, tree type)
3235 {
3236   return build1 (VA_ARG_EXPR, type, expr);
3237 }
3238
3239
3240 /* Linked list of disabled built-in functions.  */
3241
3242 typedef struct disabled_builtin
3243 {
3244   const char *name;
3245   struct disabled_builtin *next;
3246 } disabled_builtin;
3247 static disabled_builtin *disabled_builtins = NULL;
3248
3249 static bool builtin_function_disabled_p (const char *);
3250
3251 /* Disable a built-in function specified by -fno-builtin-NAME.  If NAME
3252    begins with "__builtin_", give an error.  */
3253
3254 void
3255 disable_builtin_function (const char *name)
3256 {
3257   if (strncmp (name, "__builtin_", strlen ("__builtin_")) == 0)
3258     error ("cannot disable built-in function %qs", name);
3259   else
3260     {
3261       disabled_builtin *new_disabled_builtin = XNEW (disabled_builtin);
3262       new_disabled_builtin->name = name;
3263       new_disabled_builtin->next = disabled_builtins;
3264       disabled_builtins = new_disabled_builtin;
3265     }
3266 }
3267
3268
3269 /* Return true if the built-in function NAME has been disabled, false
3270    otherwise.  */
3271
3272 static bool
3273 builtin_function_disabled_p (const char *name)
3274 {
3275   disabled_builtin *p;
3276   for (p = disabled_builtins; p != NULL; p = p->next)
3277     {
3278       if (strcmp (name, p->name) == 0)
3279         return true;
3280     }
3281   return false;
3282 }
3283
3284
3285 /* Possibly define a builtin function with one or two names.  BUILTIN_NAME
3286    is an __builtin_-prefixed name; NAME is the ordinary name; one or both
3287    of these may be NULL (though both being NULL is useless).
3288    BUILTIN_TYPE is the type of the __builtin_-prefixed function;
3289    TYPE is the type of the function with the ordinary name.  These
3290    may differ if the ordinary name is declared with a looser type to avoid
3291    conflicts with headers.  FUNCTION_CODE and CL are as for
3292    builtin_function.  If LIBRARY_NAME_P is nonzero, NAME is passed as
3293    the LIBRARY_NAME parameter to builtin_function when declaring BUILTIN_NAME.
3294    If NONANSI_P is true, the name NAME is treated as a non-ANSI name;
3295    ATTRS is the tree list representing the builtin's function attributes.
3296    Returns the declaration of BUILTIN_NAME, if any, otherwise
3297    the declaration of NAME.  Does not declare NAME if flag_no_builtin,
3298    or if NONANSI_P and flag_no_nonansi_builtin.  */
3299
3300 static tree
3301 builtin_function_2 (const char *builtin_name, const char *name,
3302                     tree builtin_type, tree type,
3303                     enum built_in_function function_code,
3304                     enum built_in_class cl, int library_name_p,
3305                     bool nonansi_p, tree attrs)
3306 {
3307   tree bdecl = NULL_TREE;
3308   tree decl = NULL_TREE;
3309
3310   if (builtin_name != 0)
3311     bdecl = lang_hooks.builtin_function (builtin_name, builtin_type,
3312                                          function_code, cl,
3313                                          library_name_p ? name : NULL, attrs);
3314
3315   if (name != 0 && !flag_no_builtin && !builtin_function_disabled_p (name)
3316       && !(nonansi_p && flag_no_nonansi_builtin))
3317     decl = lang_hooks.builtin_function (name, type, function_code, cl,
3318                                         NULL, attrs);
3319
3320   return (bdecl != 0 ? bdecl : decl);
3321 }
3322 \f
3323 /* Nonzero if the type T promotes to int.  This is (nearly) the
3324    integral promotions defined in ISO C99 6.3.1.1/2.  */
3325
3326 bool
3327 c_promoting_integer_type_p (tree t)
3328 {
3329   switch (TREE_CODE (t))
3330     {
3331     case INTEGER_TYPE:
3332       return (TYPE_MAIN_VARIANT (t) == char_type_node
3333               || TYPE_MAIN_VARIANT (t) == signed_char_type_node
3334               || TYPE_MAIN_VARIANT (t) == unsigned_char_type_node
3335               || TYPE_MAIN_VARIANT (t) == short_integer_type_node
3336               || TYPE_MAIN_VARIANT (t) == short_unsigned_type_node
3337               || TYPE_PRECISION (t) < TYPE_PRECISION (integer_type_node));
3338
3339     case ENUMERAL_TYPE:
3340       /* ??? Technically all enumerations not larger than an int
3341          promote to an int.  But this is used along code paths
3342          that only want to notice a size change.  */
3343       return TYPE_PRECISION (t) < TYPE_PRECISION (integer_type_node);
3344
3345     case BOOLEAN_TYPE:
3346       return 1;
3347
3348     default:
3349       return 0;
3350     }
3351 }
3352
3353 /* Return 1 if PARMS specifies a fixed number of parameters
3354    and none of their types is affected by default promotions.  */
3355
3356 int
3357 self_promoting_args_p (tree parms)
3358 {
3359   tree t;
3360   for (t = parms; t; t = TREE_CHAIN (t))
3361     {
3362       tree type = TREE_VALUE (t);
3363
3364       if (TREE_CHAIN (t) == 0 && type != void_type_node)
3365         return 0;
3366
3367       if (type == 0)
3368         return 0;
3369
3370       if (TYPE_MAIN_VARIANT (type) == float_type_node)
3371         return 0;
3372
3373       if (c_promoting_integer_type_p (type))
3374         return 0;
3375     }
3376   return 1;
3377 }
3378
3379 /* Recursively examines the array elements of TYPE, until a non-array
3380    element type is found.  */
3381
3382 tree
3383 strip_array_types (tree type)
3384 {
3385   while (TREE_CODE (type) == ARRAY_TYPE)
3386     type = TREE_TYPE (type);
3387
3388   return type;
3389 }
3390
3391 /* Recursively remove any '*' or '&' operator from TYPE.  */
3392 tree
3393 strip_pointer_operator (tree t)
3394 {
3395   while (POINTER_TYPE_P (t))
3396     t = TREE_TYPE (t);
3397   return t;
3398 }
3399
3400 /* Walk the statement tree, rooted at *tp.  Apply FUNC to all the
3401    sub-trees of *TP in a pre-order traversal.  FUNC is called with the
3402    DATA and the address of each sub-tree.  If FUNC returns a non-NULL
3403    value, the traversal is aborted, and the value returned by FUNC is
3404    returned.  If FUNC sets WALK_SUBTREES to zero, then the subtrees of
3405    the node being visited are not walked.
3406
3407    We don't need a without_duplicates variant of this one because the
3408    statement tree is a tree, not a graph.  */
3409
3410 tree
3411 walk_stmt_tree (tree *tp, walk_tree_fn func, void *data)
3412 {
3413   enum tree_code code;
3414   int walk_subtrees;
3415   tree result;
3416   int i, len;
3417
3418 #define WALK_SUBTREE(NODE)                              \
3419   do                                                    \
3420     {                                                   \
3421       result = walk_stmt_tree (&(NODE), func, data);    \
3422       if (result)                                       \
3423         return result;                                  \
3424     }                                                   \
3425   while (0)
3426
3427   /* Skip empty subtrees.  */
3428   if (!*tp)
3429     return NULL_TREE;
3430
3431   /* Skip subtrees below non-statement nodes.  */
3432   if (!STATEMENT_CODE_P (TREE_CODE (*tp)))
3433     return NULL_TREE;
3434
3435   /* Call the function.  */
3436   walk_subtrees = 1;
3437   result = (*func) (tp, &walk_subtrees, data);
3438
3439   /* If we found something, return it.  */
3440   if (result)
3441     return result;
3442
3443   /* FUNC may have modified the tree, recheck that we're looking at a
3444      statement node.  */
3445   code = TREE_CODE (*tp);
3446   if (!STATEMENT_CODE_P (code))
3447     return NULL_TREE;
3448
3449   /* Visit the subtrees unless FUNC decided that there was nothing
3450      interesting below this point in the tree.  */
3451   if (walk_subtrees)
3452     {
3453       /* Walk over all the sub-trees of this operand.  Statement nodes
3454          never contain RTL, and we needn't worry about TARGET_EXPRs.  */
3455       len = TREE_CODE_LENGTH (code);
3456
3457       /* Go through the subtrees.  We need to do this in forward order so
3458          that the scope of a FOR_EXPR is handled properly.  */
3459       for (i = 0; i < len; ++i)
3460         WALK_SUBTREE (TREE_OPERAND (*tp, i));
3461     }
3462
3463   /* Finally visit the chain.  This can be tail-recursion optimized if
3464      we write it this way.  */
3465   return walk_stmt_tree (&TREE_CHAIN (*tp), func, data);
3466
3467 #undef WALK_SUBTREE
3468 }
3469
3470 /* Used to compare case labels.  K1 and K2 are actually tree nodes
3471    representing case labels, or NULL_TREE for a `default' label.
3472    Returns -1 if K1 is ordered before K2, -1 if K1 is ordered after
3473    K2, and 0 if K1 and K2 are equal.  */
3474
3475 int
3476 case_compare (splay_tree_key k1, splay_tree_key k2)
3477 {
3478   /* Consider a NULL key (such as arises with a `default' label) to be
3479      smaller than anything else.  */
3480   if (!k1)
3481     return k2 ? -1 : 0;
3482   else if (!k2)
3483     return k1 ? 1 : 0;
3484
3485   return tree_int_cst_compare ((tree) k1, (tree) k2);
3486 }
3487
3488 /* Process a case label for the range LOW_VALUE ... HIGH_VALUE.  If
3489    LOW_VALUE and HIGH_VALUE are both NULL_TREE then this case label is
3490    actually a `default' label.  If only HIGH_VALUE is NULL_TREE, then
3491    case label was declared using the usual C/C++ syntax, rather than
3492    the GNU case range extension.  CASES is a tree containing all the
3493    case ranges processed so far; COND is the condition for the
3494    switch-statement itself.  Returns the CASE_LABEL_EXPR created, or
3495    ERROR_MARK_NODE if no CASE_LABEL_EXPR is created.  */
3496
3497 tree
3498 c_add_case_label (splay_tree cases, tree cond, tree orig_type,
3499                   tree low_value, tree high_value)
3500 {
3501   tree type;
3502   tree label;
3503   tree case_label;
3504   splay_tree_node node;
3505
3506   /* Create the LABEL_DECL itself.  */
3507   label = create_artificial_label ();
3508
3509   /* If there was an error processing the switch condition, bail now
3510      before we get more confused.  */
3511   if (!cond || cond == error_mark_node)
3512     goto error_out;
3513
3514   if ((low_value && TREE_TYPE (low_value)
3515        && POINTER_TYPE_P (TREE_TYPE (low_value)))
3516       || (high_value && TREE_TYPE (high_value)
3517           && POINTER_TYPE_P (TREE_TYPE (high_value))))
3518     error ("pointers are not permitted as case values");
3519
3520   /* Case ranges are a GNU extension.  */
3521   if (high_value && pedantic)
3522     pedwarn ("range expressions in switch statements are non-standard");
3523
3524   type = TREE_TYPE (cond);
3525   if (low_value)
3526     {
3527       low_value = check_case_value (low_value);
3528       low_value = convert_and_check (type, low_value);
3529     }
3530   if (high_value)
3531     {
3532       high_value = check_case_value (high_value);
3533       high_value = convert_and_check (type, high_value);
3534     }
3535
3536   /* If an error has occurred, bail out now.  */
3537   if (low_value == error_mark_node || high_value == error_mark_node)
3538     goto error_out;
3539
3540   /* If the LOW_VALUE and HIGH_VALUE are the same, then this isn't
3541      really a case range, even though it was written that way.  Remove
3542      the HIGH_VALUE to simplify later processing.  */
3543   if (tree_int_cst_equal (low_value, high_value))
3544     high_value = NULL_TREE;
3545   if (low_value && high_value
3546       && !tree_int_cst_lt (low_value, high_value))
3547     warning ("empty range specified");
3548
3549   /* See if the case is in range of the type of the original testing
3550      expression.  If both low_value and high_value are out of range,
3551      don't insert the case label and return NULL_TREE.  */
3552   if (low_value
3553       && ! check_case_bounds (type, orig_type,
3554                               &low_value, high_value ? &high_value : NULL))
3555     return NULL_TREE;
3556
3557   /* Look up the LOW_VALUE in the table of case labels we already
3558      have.  */
3559   node = splay_tree_lookup (cases, (splay_tree_key) low_value);
3560   /* If there was not an exact match, check for overlapping ranges.
3561      There's no need to do this if there's no LOW_VALUE or HIGH_VALUE;
3562      that's a `default' label and the only overlap is an exact match.  */
3563   if (!node && (low_value || high_value))
3564     {
3565       splay_tree_node low_bound;
3566       splay_tree_node high_bound;
3567
3568       /* Even though there wasn't an exact match, there might be an
3569          overlap between this case range and another case range.
3570          Since we've (inductively) not allowed any overlapping case
3571          ranges, we simply need to find the greatest low case label
3572          that is smaller that LOW_VALUE, and the smallest low case
3573          label that is greater than LOW_VALUE.  If there is an overlap
3574          it will occur in one of these two ranges.  */
3575       low_bound = splay_tree_predecessor (cases,
3576                                           (splay_tree_key) low_value);
3577       high_bound = splay_tree_successor (cases,
3578                                          (splay_tree_key) low_value);
3579
3580       /* Check to see if the LOW_BOUND overlaps.  It is smaller than
3581          the LOW_VALUE, so there is no need to check unless the
3582          LOW_BOUND is in fact itself a case range.  */
3583       if (low_bound
3584           && CASE_HIGH ((tree) low_bound->value)
3585           && tree_int_cst_compare (CASE_HIGH ((tree) low_bound->value),
3586                                     low_value) >= 0)
3587         node = low_bound;
3588       /* Check to see if the HIGH_BOUND overlaps.  The low end of that
3589          range is bigger than the low end of the current range, so we
3590          are only interested if the current range is a real range, and
3591          not an ordinary case label.  */
3592       else if (high_bound
3593                && high_value
3594                && (tree_int_cst_compare ((tree) high_bound->key,
3595                                          high_value)
3596                    <= 0))
3597         node = high_bound;
3598     }
3599   /* If there was an overlap, issue an error.  */
3600   if (node)
3601     {
3602       tree duplicate = CASE_LABEL ((tree) node->value);
3603
3604       if (high_value)
3605         {
3606           error ("duplicate (or overlapping) case value");
3607           error ("%Jthis is the first entry overlapping that value", duplicate);
3608         }
3609       else if (low_value)
3610         {
3611           error ("duplicate case value") ;
3612           error ("%Jpreviously used here", duplicate);
3613         }
3614       else
3615         {
3616           error ("multiple default labels in one switch");
3617           error ("%Jthis is the first default label", duplicate);
3618         }
3619       goto error_out;
3620     }
3621
3622   /* Add a CASE_LABEL to the statement-tree.  */
3623   case_label = add_stmt (build_case_label (low_value, high_value, label));
3624   /* Register this case label in the splay tree.  */
3625   splay_tree_insert (cases,
3626                      (splay_tree_key) low_value,
3627                      (splay_tree_value) case_label);
3628
3629   return case_label;
3630
3631  error_out:
3632   /* Add a label so that the back-end doesn't think that the beginning of
3633      the switch is unreachable.  Note that we do not add a case label, as
3634      that just leads to duplicates and thence to aborts later on.  */
3635   if (!cases->root)
3636     {
3637       tree t = create_artificial_label ();
3638       add_stmt (build_stmt (LABEL_EXPR, t));
3639     }
3640   return error_mark_node;
3641 }
3642
3643 /* Subroutines of c_do_switch_warnings, called via splay_tree_foreach.
3644    Used to verify that case values match up with enumerator values.  */
3645
3646 static void
3647 match_case_to_enum_1 (tree key, tree type, tree label)
3648 {
3649   char buf[2 + 2*HOST_BITS_PER_WIDE_INT/4 + 1];
3650
3651   /* ??? Not working too hard to print the double-word value.
3652      Should perhaps be done with %lwd in the diagnostic routines?  */
3653   if (TREE_INT_CST_HIGH (key) == 0)
3654     snprintf (buf, sizeof (buf), HOST_WIDE_INT_PRINT_UNSIGNED,
3655               TREE_INT_CST_LOW (key));
3656   else if (!TYPE_UNSIGNED (type)
3657            && TREE_INT_CST_HIGH (key) == -1
3658            && TREE_INT_CST_LOW (key) != 0)
3659     snprintf (buf, sizeof (buf), "-" HOST_WIDE_INT_PRINT_UNSIGNED,
3660               -TREE_INT_CST_LOW (key));
3661   else
3662     snprintf (buf, sizeof (buf), HOST_WIDE_INT_PRINT_DOUBLE_HEX,
3663               TREE_INT_CST_HIGH (key), TREE_INT_CST_LOW (key));
3664
3665   if (TYPE_NAME (type) == 0)
3666     warning ("%Jcase value %qs not in enumerated type",
3667              CASE_LABEL (label), buf);
3668   else
3669     warning ("%Jcase value %qs not in enumerated type %qT",
3670              CASE_LABEL (label), buf, type);
3671 }
3672
3673 static int
3674 match_case_to_enum (splay_tree_node node, void *data)
3675 {
3676   tree label = (tree) node->value;
3677   tree type = (tree) data;
3678
3679   /* Skip default case.  */
3680   if (!CASE_LOW (label))
3681     return 0;
3682
3683   /* If TREE_ADDRESSABLE is not set, that means CASE_LOW did not appear
3684      when we did our enum->case scan.  Reset our scratch bit after.  */
3685   if (!TREE_ADDRESSABLE (label))
3686     match_case_to_enum_1 (CASE_LOW (label), type, label);
3687   else
3688     TREE_ADDRESSABLE (label) = 0;
3689
3690   /* If CASE_HIGH is non-null, we have a range.  Here we must search.
3691      Note that the old code in stmt.c did not check for the values in
3692      the range either, just the endpoints.  */
3693   if (CASE_HIGH (label))
3694     {
3695       tree chain, key = CASE_HIGH (label);
3696
3697       for (chain = TYPE_VALUES (type);
3698            chain && !tree_int_cst_equal (key, TREE_VALUE (chain));
3699            chain = TREE_CHAIN (chain))
3700         continue;
3701       if (!chain)
3702         match_case_to_enum_1 (key, type, label);
3703     }
3704
3705   return 0;
3706 }
3707
3708 /* Handle -Wswitch*.  Called from the front end after parsing the switch
3709    construct.  */
3710 /* ??? Should probably be somewhere generic, since other languages besides
3711    C and C++ would want this.  We'd want to agree on the datastructure,
3712    however, which is a problem.  Alternately, we operate on gimplified
3713    switch_exprs, which I don't especially like.  At the moment, however,
3714    C/C++ are the only tree-ssa languages that support enumerations at all,
3715    so the point is moot.  */
3716
3717 void
3718 c_do_switch_warnings (splay_tree cases, tree switch_stmt)
3719 {
3720   splay_tree_node default_node;
3721   location_t switch_location;
3722   tree type;
3723
3724   if (!warn_switch && !warn_switch_enum && !warn_switch_default)
3725     return;
3726
3727   if (EXPR_HAS_LOCATION (switch_stmt))
3728     switch_location = EXPR_LOCATION (switch_stmt);
3729   else
3730     switch_location = input_location;
3731
3732   type = SWITCH_TYPE (switch_stmt);
3733
3734   default_node = splay_tree_lookup (cases, (splay_tree_key) NULL);
3735   if (warn_switch_default && !default_node)
3736     warning ("%Hswitch missing default case", &switch_location);
3737
3738   /* If the switch expression was an enumerated type, check that
3739      exactly all enumeration literals are covered by the cases.
3740      The check is made when -Wswitch was specified and there is no
3741      default case, or when -Wswitch-enum was specified.  */
3742   if (((warn_switch && !default_node) || warn_switch_enum)
3743       && type && TREE_CODE (type) == ENUMERAL_TYPE
3744       && TREE_CODE (SWITCH_COND (switch_stmt)) != INTEGER_CST)
3745     {
3746       tree chain;
3747
3748       /* The time complexity here is O(N*lg(N)) worst case, but for the
3749          common case of monotonically increasing enumerators, it is
3750          O(N), since the nature of the splay tree will keep the next
3751          element adjacent to the root at all times.  */
3752
3753       for (chain = TYPE_VALUES (type); chain; chain = TREE_CHAIN (chain))
3754         {
3755           splay_tree_node node
3756             = splay_tree_lookup (cases, (splay_tree_key) TREE_VALUE (chain));
3757
3758           if (node)
3759             {
3760               /* Mark the CASE_LOW part of the case entry as seen, so
3761                  that we save time later.  Choose TREE_ADDRESSABLE
3762                  randomly as a bit that won't have been set to-date.  */
3763               tree label = (tree) node->value;
3764               TREE_ADDRESSABLE (label) = 1;
3765             }
3766           else
3767             {
3768               /* Warn if there are enumerators that don't correspond to
3769                  case expressions.  */
3770               warning ("%Henumeration value %qE not handled in switch",
3771                        &switch_location, TREE_PURPOSE (chain));
3772             }
3773         }
3774
3775       /* Warn if there are case expressions that don't correspond to
3776          enumerators.  This can occur since C and C++ don't enforce
3777          type-checking of assignments to enumeration variables.
3778
3779          The time complexity here is O(N**2) worst case, since we've
3780          not sorted the enumeration values.  However, in the absence
3781          of case ranges this is O(N), since all single cases that
3782          corresponded to enumerations have been marked above.  */
3783
3784       splay_tree_foreach (cases, match_case_to_enum, type);
3785     }
3786 }
3787
3788 /* Finish an expression taking the address of LABEL (an
3789    IDENTIFIER_NODE).  Returns an expression for the address.  */
3790
3791 tree
3792 finish_label_address_expr (tree label)
3793 {
3794   tree result;
3795
3796   if (pedantic)
3797     pedwarn ("taking the address of a label is non-standard");
3798
3799   if (label == error_mark_node)
3800     return error_mark_node;
3801
3802   label = lookup_label (label);
3803   if (label == NULL_TREE)
3804     result = null_pointer_node;
3805   else
3806     {
3807       TREE_USED (label) = 1;
3808       result = build1 (ADDR_EXPR, ptr_type_node, label);
3809       /* The current function in not necessarily uninlinable.
3810          Computed gotos are incompatible with inlining, but the value
3811          here could be used only in a diagnostic, for example.  */
3812     }
3813
3814   return result;
3815 }
3816
3817 /* Hook used by expand_expr to expand language-specific tree codes.  */
3818 /* The only things that should go here are bits needed to expand
3819    constant initializers.  Everything else should be handled by the
3820    gimplification routines.  */
3821
3822 rtx
3823 c_expand_expr (tree exp, rtx target, enum machine_mode tmode,
3824                int modifier /* Actually enum_modifier.  */,
3825                rtx *alt_rtl)
3826 {
3827   switch (TREE_CODE (exp))
3828     {
3829     case COMPOUND_LITERAL_EXPR:
3830       {
3831         /* Initialize the anonymous variable declared in the compound
3832            literal, then return the variable.  */
3833         tree decl = COMPOUND_LITERAL_EXPR_DECL (exp);
3834         emit_local_var (decl);
3835         return expand_expr_real (decl, target, tmode, modifier, alt_rtl);
3836       }
3837
3838     default:
3839       gcc_unreachable ();
3840     }
3841 }
3842
3843 /* Hook used by staticp to handle language-specific tree codes.  */
3844
3845 tree
3846 c_staticp (tree exp)
3847 {
3848   return (TREE_CODE (exp) == COMPOUND_LITERAL_EXPR
3849           && TREE_STATIC (COMPOUND_LITERAL_EXPR_DECL (exp))
3850           ? exp : NULL);
3851 }
3852 \f
3853
3854 /* Given a boolean expression ARG, return a tree representing an increment
3855    or decrement (as indicated by CODE) of ARG.  The front end must check for
3856    invalid cases (e.g., decrement in C++).  */
3857 tree
3858 boolean_increment (enum tree_code code, tree arg)
3859 {
3860   tree val;
3861   tree true_res = boolean_true_node;
3862
3863   arg = stabilize_reference (arg);
3864   switch (code)
3865     {
3866     case PREINCREMENT_EXPR:
3867       val = build2 (MODIFY_EXPR, TREE_TYPE (arg), arg, true_res);
3868       break;
3869     case POSTINCREMENT_EXPR:
3870       val = build2 (MODIFY_EXPR, TREE_TYPE (arg), arg, true_res);
3871       arg = save_expr (arg);
3872       val = build2 (COMPOUND_EXPR, TREE_TYPE (arg), val, arg);
3873       val = build2 (COMPOUND_EXPR, TREE_TYPE (arg), arg, val);
3874       break;
3875     case PREDECREMENT_EXPR:
3876       val = build2 (MODIFY_EXPR, TREE_TYPE (arg), arg,
3877                     invert_truthvalue (arg));
3878       break;
3879     case POSTDECREMENT_EXPR:
3880       val = build2 (MODIFY_EXPR, TREE_TYPE (arg), arg,
3881                     invert_truthvalue (arg));
3882       arg = save_expr (arg);
3883       val = build2 (COMPOUND_EXPR, TREE_TYPE (arg), val, arg);
3884       val = build2 (COMPOUND_EXPR, TREE_TYPE (arg), arg, val);
3885       break;
3886     default:
3887       gcc_unreachable ();
3888     }
3889   TREE_SIDE_EFFECTS (val) = 1;
3890   return val;
3891 }
3892 \f
3893 /* Built-in macros for stddef.h, that require macros defined in this
3894    file.  */
3895 void
3896 c_stddef_cpp_builtins(void)
3897 {
3898   builtin_define_with_value ("__SIZE_TYPE__", SIZE_TYPE, 0);
3899   builtin_define_with_value ("__PTRDIFF_TYPE__", PTRDIFF_TYPE, 0);
3900   builtin_define_with_value ("__WCHAR_TYPE__", MODIFIED_WCHAR_TYPE, 0);
3901   builtin_define_with_value ("__WINT_TYPE__", WINT_TYPE, 0);
3902   builtin_define_with_value ("__INTMAX_TYPE__", INTMAX_TYPE, 0);
3903   builtin_define_with_value ("__UINTMAX_TYPE__", UINTMAX_TYPE, 0);
3904 }
3905
3906 static void
3907 c_init_attributes (void)
3908 {
3909   /* Fill in the built_in_attributes array.  */
3910 #define DEF_ATTR_NULL_TREE(ENUM)                                \
3911   built_in_attributes[(int) ENUM] = NULL_TREE;
3912 #define DEF_ATTR_INT(ENUM, VALUE)                               \
3913   built_in_attributes[(int) ENUM] = build_int_cst (NULL_TREE, VALUE);
3914 #define DEF_ATTR_IDENT(ENUM, STRING)                            \
3915   built_in_attributes[(int) ENUM] = get_identifier (STRING);
3916 #define DEF_ATTR_TREE_LIST(ENUM, PURPOSE, VALUE, CHAIN) \
3917   built_in_attributes[(int) ENUM]                       \
3918     = tree_cons (built_in_attributes[(int) PURPOSE],    \
3919                  built_in_attributes[(int) VALUE],      \
3920                  built_in_attributes[(int) CHAIN]);
3921 #include "builtin-attrs.def"
3922 #undef DEF_ATTR_NULL_TREE
3923 #undef DEF_ATTR_INT
3924 #undef DEF_ATTR_IDENT
3925 #undef DEF_ATTR_TREE_LIST
3926 }
3927
3928 /* Attribute handlers common to C front ends.  */
3929
3930 /* Handle a "packed" attribute; arguments as in
3931    struct attribute_spec.handler.  */
3932
3933 static tree
3934 handle_packed_attribute (tree *node, tree name, tree ARG_UNUSED (args),
3935                          int flags, bool *no_add_attrs)
3936 {
3937   if (TYPE_P (*node))
3938     {
3939       if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
3940         *node = build_variant_type_copy (*node);
3941       TYPE_PACKED (*node) = 1;
3942       if (TYPE_MAIN_VARIANT (*node) == *node)
3943         {
3944           /* If it is the main variant, then pack the other variants
3945              too. This happens in,
3946
3947              struct Foo {
3948                struct Foo const *ptr; // creates a variant w/o packed flag
3949                } __ attribute__((packed)); // packs it now.
3950           */
3951           tree probe;
3952
3953           for (probe = *node; probe; probe = TYPE_NEXT_VARIANT (probe))
3954             TYPE_PACKED (probe) = 1;
3955         }
3956
3957     }
3958   else if (TREE_CODE (*node) == FIELD_DECL)
3959     DECL_PACKED (*node) = 1;
3960   /* We can't set DECL_PACKED for a VAR_DECL, because the bit is
3961      used for DECL_REGISTER.  It wouldn't mean anything anyway.
3962      We can't set DECL_PACKED on the type of a TYPE_DECL, because
3963      that changes what the typedef is typing.  */
3964   else
3965     {
3966       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
3967       *no_add_attrs = true;
3968     }
3969
3970   return NULL_TREE;
3971 }
3972
3973 /* Handle a "nocommon" attribute; arguments as in
3974    struct attribute_spec.handler.  */
3975
3976 static tree
3977 handle_nocommon_attribute (tree *node, tree name,
3978                            tree ARG_UNUSED (args),
3979                            int ARG_UNUSED (flags), bool *no_add_attrs)
3980 {
3981   if (TREE_CODE (*node) == VAR_DECL)
3982     DECL_COMMON (*node) = 0;
3983   else
3984     {
3985       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
3986       *no_add_attrs = true;
3987     }
3988
3989   return NULL_TREE;
3990 }
3991
3992 /* Handle a "common" attribute; arguments as in
3993    struct attribute_spec.handler.  */
3994
3995 static tree
3996 handle_common_attribute (tree *node, tree name, tree ARG_UNUSED (args),
3997                          int ARG_UNUSED (flags), bool *no_add_attrs)
3998 {
3999   if (TREE_CODE (*node) == VAR_DECL)
4000     DECL_COMMON (*node) = 1;
4001   else
4002     {
4003       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
4004       *no_add_attrs = true;
4005     }
4006
4007   return NULL_TREE;
4008 }
4009
4010 /* Handle a "noreturn" attribute; arguments as in
4011    struct attribute_spec.handler.  */
4012
4013 static tree
4014 handle_noreturn_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4015                            int ARG_UNUSED (flags), bool *no_add_attrs)
4016 {
4017   tree type = TREE_TYPE (*node);
4018
4019   /* See FIXME comment in c_common_attribute_table.  */
4020   if (TREE_CODE (*node) == FUNCTION_DECL)
4021     TREE_THIS_VOLATILE (*node) = 1;
4022   else if (TREE_CODE (type) == POINTER_TYPE
4023            && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE)
4024     TREE_TYPE (*node)
4025       = build_pointer_type
4026         (build_type_variant (TREE_TYPE (type),
4027                              TYPE_READONLY (TREE_TYPE (type)), 1));
4028   else
4029     {
4030       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
4031       *no_add_attrs = true;
4032     }
4033
4034   return NULL_TREE;
4035 }
4036
4037 /* Handle a "noinline" attribute; arguments as in
4038    struct attribute_spec.handler.  */
4039
4040 static tree
4041 handle_noinline_attribute (tree *node, tree name,
4042                            tree ARG_UNUSED (args),
4043                            int ARG_UNUSED (flags), bool *no_add_attrs)
4044 {
4045   if (TREE_CODE (*node) == FUNCTION_DECL)
4046     DECL_UNINLINABLE (*node) = 1;
4047   else
4048     {
4049       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
4050       *no_add_attrs = true;
4051     }
4052
4053   return NULL_TREE;
4054 }
4055
4056 /* Handle a "always_inline" attribute; arguments as in
4057    struct attribute_spec.handler.  */
4058
4059 static tree
4060 handle_always_inline_attribute (tree *node, tree name,
4061                                 tree ARG_UNUSED (args),
4062                                 int ARG_UNUSED (flags),
4063                                 bool *no_add_attrs)
4064 {
4065   if (TREE_CODE (*node) == FUNCTION_DECL)
4066     {
4067       /* Do nothing else, just set the attribute.  We'll get at
4068          it later with lookup_attribute.  */
4069     }
4070   else
4071     {
4072       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
4073       *no_add_attrs = true;
4074     }
4075
4076   return NULL_TREE;
4077 }
4078
4079 /* Handle a "used" attribute; arguments as in
4080    struct attribute_spec.handler.  */
4081
4082 static tree
4083 handle_used_attribute (tree *pnode, tree name, tree ARG_UNUSED (args),
4084                        int ARG_UNUSED (flags), bool *no_add_attrs)
4085 {
4086   tree node = *pnode;
4087
4088   if (TREE_CODE (node) == FUNCTION_DECL
4089       || (TREE_CODE (node) == VAR_DECL && TREE_STATIC (node)))
4090     {
4091       TREE_USED (node) = 1;
4092       DECL_PRESERVE_P (node) = 1;
4093     }
4094   else
4095     {
4096       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
4097       *no_add_attrs = true;
4098     }
4099
4100   return NULL_TREE;
4101 }
4102
4103 /* Handle a "unused" attribute; arguments as in
4104    struct attribute_spec.handler.  */
4105
4106 static tree
4107 handle_unused_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4108                          int flags, bool *no_add_attrs)
4109 {
4110   if (DECL_P (*node))
4111     {
4112       tree decl = *node;
4113
4114       if (TREE_CODE (decl) == PARM_DECL
4115           || TREE_CODE (decl) == VAR_DECL
4116           || TREE_CODE (decl) == FUNCTION_DECL
4117           || TREE_CODE (decl) == LABEL_DECL
4118           || TREE_CODE (decl) == TYPE_DECL)
4119         TREE_USED (decl) = 1;
4120       else
4121         {
4122           warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
4123           *no_add_attrs = true;
4124         }
4125     }
4126   else
4127     {
4128       if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
4129         *node = build_variant_type_copy (*node);
4130       TREE_USED (*node) = 1;
4131     }
4132
4133   return NULL_TREE;
4134 }
4135
4136 /* Handle a "const" attribute; arguments as in
4137    struct attribute_spec.handler.  */
4138
4139 static tree
4140 handle_const_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4141                         int ARG_UNUSED (flags), bool *no_add_attrs)
4142 {
4143   tree type = TREE_TYPE (*node);
4144
4145   /* See FIXME comment on noreturn in c_common_attribute_table.  */
4146   if (TREE_CODE (*node) == FUNCTION_DECL)
4147     TREE_READONLY (*node) = 1;
4148   else if (TREE_CODE (type) == POINTER_TYPE
4149            && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE)
4150     TREE_TYPE (*node)
4151       = build_pointer_type
4152         (build_type_variant (TREE_TYPE (type), 1,
4153                              TREE_THIS_VOLATILE (TREE_TYPE (type))));
4154   else
4155     {
4156       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
4157       *no_add_attrs = true;
4158     }
4159
4160   return NULL_TREE;
4161 }
4162
4163 /* Handle a "transparent_union" attribute; arguments as in
4164    struct attribute_spec.handler.  */
4165
4166 static tree
4167 handle_transparent_union_attribute (tree *node, tree name,
4168                                     tree ARG_UNUSED (args), int flags,
4169                                     bool *no_add_attrs)
4170 {
4171   tree decl = NULL_TREE;
4172   tree *type = NULL;
4173   int is_type = 0;
4174
4175   if (DECL_P (*node))
4176     {
4177       decl = *node;
4178       type = &TREE_TYPE (decl);
4179       is_type = TREE_CODE (*node) == TYPE_DECL;
4180     }
4181   else if (TYPE_P (*node))
4182     type = node, is_type = 1;
4183
4184   if (is_type
4185       && TREE_CODE (*type) == UNION_TYPE
4186       && (decl == 0
4187           || (TYPE_FIELDS (*type) != 0
4188               && TYPE_MODE (*type) == DECL_MODE (TYPE_FIELDS (*type)))))
4189     {
4190       if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
4191         *type = build_variant_type_copy (*type);
4192       TYPE_TRANSPARENT_UNION (*type) = 1;
4193     }
4194   else if (decl != 0 && TREE_CODE (decl) == PARM_DECL
4195            && TREE_CODE (*type) == UNION_TYPE
4196            && TYPE_MODE (*type) == DECL_MODE (TYPE_FIELDS (*type)))
4197     DECL_TRANSPARENT_UNION (decl) = 1;
4198   else
4199     {
4200       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
4201       *no_add_attrs = true;
4202     }
4203
4204   return NULL_TREE;
4205 }
4206
4207 /* Handle a "constructor" attribute; arguments as in
4208    struct attribute_spec.handler.  */
4209
4210 static tree
4211 handle_constructor_attribute (tree *node, tree name,
4212                               tree ARG_UNUSED (args),
4213                               int ARG_UNUSED (flags),
4214                               bool *no_add_attrs)
4215 {
4216   tree decl = *node;
4217   tree type = TREE_TYPE (decl);
4218
4219   if (TREE_CODE (decl) == FUNCTION_DECL
4220       && TREE_CODE (type) == FUNCTION_TYPE
4221       && decl_function_context (decl) == 0)
4222     {
4223       DECL_STATIC_CONSTRUCTOR (decl) = 1;
4224       TREE_USED (decl) = 1;
4225     }
4226   else
4227     {
4228       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
4229       *no_add_attrs = true;
4230     }
4231
4232   return NULL_TREE;
4233 }
4234
4235 /* Handle a "destructor" attribute; arguments as in
4236    struct attribute_spec.handler.  */
4237
4238 static tree
4239 handle_destructor_attribute (tree *node, tree name,
4240                              tree ARG_UNUSED (args),
4241                              int ARG_UNUSED (flags),
4242                              bool *no_add_attrs)
4243 {
4244   tree decl = *node;
4245   tree type = TREE_TYPE (decl);
4246
4247   if (TREE_CODE (decl) == FUNCTION_DECL
4248       && TREE_CODE (type) == FUNCTION_TYPE
4249       && decl_function_context (decl) == 0)
4250     {
4251       DECL_STATIC_DESTRUCTOR (decl) = 1;
4252       TREE_USED (decl) = 1;
4253     }
4254   else
4255     {
4256       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
4257       *no_add_attrs = true;
4258     }
4259
4260   return NULL_TREE;
4261 }
4262
4263 /* Handle a "mode" attribute; arguments as in
4264    struct attribute_spec.handler.  */
4265
4266 static tree
4267 handle_mode_attribute (tree *node, tree name, tree args,
4268                        int ARG_UNUSED (flags), bool *no_add_attrs)
4269 {
4270   tree type = *node;
4271
4272   *no_add_attrs = true;
4273
4274   if (TREE_CODE (TREE_VALUE (args)) != IDENTIFIER_NODE)
4275     warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
4276   else
4277     {
4278       int j;
4279       const char *p = IDENTIFIER_POINTER (TREE_VALUE (args));
4280       int len = strlen (p);
4281       enum machine_mode mode = VOIDmode;
4282       tree typefm;
4283       bool valid_mode;
4284
4285       if (len > 4 && p[0] == '_' && p[1] == '_'
4286           && p[len - 1] == '_' && p[len - 2] == '_')
4287         {
4288           char *newp = (char *) alloca (len - 1);
4289
4290           strcpy (newp, &p[2]);
4291           newp[len - 4] = '\0';
4292           p = newp;
4293         }
4294
4295       /* Change this type to have a type with the specified mode.
4296          First check for the special modes.  */
4297       if (! strcmp (p, "byte"))
4298         mode = byte_mode;
4299       else if (!strcmp (p, "word"))
4300         mode = word_mode;
4301       else if (! strcmp (p, "pointer"))
4302         mode = ptr_mode;
4303       else
4304         for (j = 0; j < NUM_MACHINE_MODES; j++)
4305           if (!strcmp (p, GET_MODE_NAME (j)))
4306             mode = (enum machine_mode) j;
4307
4308       if (mode == VOIDmode)
4309         {
4310           error ("unknown machine mode %<%s%>", p);
4311           return NULL_TREE;
4312         }
4313
4314       valid_mode = false;
4315       switch (GET_MODE_CLASS (mode))
4316         {
4317         case MODE_INT:
4318         case MODE_PARTIAL_INT:
4319         case MODE_FLOAT:
4320           valid_mode = targetm.scalar_mode_supported_p (mode);
4321           break;
4322
4323         case MODE_COMPLEX_INT:
4324         case MODE_COMPLEX_FLOAT:
4325           valid_mode = targetm.scalar_mode_supported_p (GET_MODE_INNER (mode));
4326           break;
4327
4328         case MODE_VECTOR_INT:
4329         case MODE_VECTOR_FLOAT:
4330           warning ("specifying vector types with __attribute__ ((mode)) "
4331                    "is deprecated");
4332           warning ("use __attribute__ ((vector_size)) instead");
4333           valid_mode = vector_mode_valid_p (mode);
4334           break;
4335
4336         default:
4337           break;
4338         }
4339       if (!valid_mode)
4340         {
4341           error ("unable to emulate %<%s%>", p);
4342           return NULL_TREE;
4343         }
4344
4345       if (POINTER_TYPE_P (type))
4346         {
4347           tree (*fn)(tree, enum machine_mode, bool);
4348
4349           if (!targetm.valid_pointer_mode (mode))
4350             {
4351               error ("invalid pointer mode %<%s%>", p);
4352               return NULL_TREE;
4353             }
4354
4355           if (TREE_CODE (type) == POINTER_TYPE)
4356             fn = build_pointer_type_for_mode;
4357           else
4358             fn = build_reference_type_for_mode;
4359           typefm = fn (TREE_TYPE (type), mode, false);
4360         }
4361       else
4362         typefm = lang_hooks.types.type_for_mode (mode, TYPE_UNSIGNED (type));
4363
4364       if (typefm == NULL_TREE)
4365         {
4366           error ("no data type for mode %<%s%>", p);
4367           return NULL_TREE;
4368         }
4369       else if (TREE_CODE (type) == ENUMERAL_TYPE)
4370         {
4371           /* For enumeral types, copy the precision from the integer
4372              type returned above.  If not an INTEGER_TYPE, we can't use
4373              this mode for this type.  */
4374           if (TREE_CODE (typefm) != INTEGER_TYPE)
4375             {
4376               error ("cannot use mode %qs for enumeral types",
4377                      GET_MODE_NAME (mode));
4378               return NULL_TREE;
4379             }
4380
4381           if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
4382             type = build_variant_type_copy (type);
4383           TYPE_PRECISION (type) = TYPE_PRECISION (typefm);
4384           typefm = type;
4385         }
4386       *node = typefm;
4387
4388       /* No need to layout the type here.  The caller should do this.  */
4389     }
4390
4391   return NULL_TREE;
4392 }
4393
4394 /* Handle a "section" attribute; arguments as in
4395    struct attribute_spec.handler.  */
4396
4397 static tree
4398 handle_section_attribute (tree *node, tree ARG_UNUSED (name), tree args,
4399                           int ARG_UNUSED (flags), bool *no_add_attrs)
4400 {
4401   tree decl = *node;
4402
4403   if (targetm.have_named_sections)
4404     {
4405       user_defined_section_attribute = true;
4406
4407       if ((TREE_CODE (decl) == FUNCTION_DECL
4408            || TREE_CODE (decl) == VAR_DECL)
4409           && TREE_CODE (TREE_VALUE (args)) == STRING_CST)
4410         {
4411           if (TREE_CODE (decl) == VAR_DECL
4412               && current_function_decl != NULL_TREE
4413               && ! TREE_STATIC (decl))
4414             {
4415               error ("%Jsection attribute cannot be specified for "
4416                      "local variables", decl);
4417               *no_add_attrs = true;
4418             }
4419
4420           /* The decl may have already been given a section attribute
4421              from a previous declaration.  Ensure they match.  */
4422           else if (DECL_SECTION_NAME (decl) != NULL_TREE
4423                    && strcmp (TREE_STRING_POINTER (DECL_SECTION_NAME (decl)),
4424                               TREE_STRING_POINTER (TREE_VALUE (args))) != 0)
4425             {
4426               error ("%Jsection of %qD conflicts with previous declaration",
4427                      *node, *node);
4428               *no_add_attrs = true;
4429             }
4430           else
4431             DECL_SECTION_NAME (decl) = TREE_VALUE (args);
4432         }
4433       else
4434         {
4435           error ("%Jsection attribute not allowed for %qD", *node, *node);
4436           *no_add_attrs = true;
4437         }
4438     }
4439   else
4440     {
4441       error ("%Jsection attributes are not supported for this target", *node);
4442       *no_add_attrs = true;
4443     }
4444
4445   return NULL_TREE;
4446 }
4447
4448 /* Handle a "aligned" attribute; arguments as in
4449    struct attribute_spec.handler.  */
4450
4451 static tree
4452 handle_aligned_attribute (tree *node, tree ARG_UNUSED (name), tree args,
4453                           int flags, bool *no_add_attrs)
4454 {
4455   tree decl = NULL_TREE;
4456   tree *type = NULL;
4457   int is_type = 0;
4458   tree align_expr = (args ? TREE_VALUE (args)
4459                      : size_int (BIGGEST_ALIGNMENT / BITS_PER_UNIT));
4460   int i;
4461
4462   if (DECL_P (*node))
4463     {
4464       decl = *node;
4465       type = &TREE_TYPE (decl);
4466       is_type = TREE_CODE (*node) == TYPE_DECL;
4467     }
4468   else if (TYPE_P (*node))
4469     type = node, is_type = 1;
4470
4471   /* Strip any NOPs of any kind.  */
4472   while (TREE_CODE (align_expr) == NOP_EXPR
4473          || TREE_CODE (align_expr) == CONVERT_EXPR
4474          || TREE_CODE (align_expr) == NON_LVALUE_EXPR)
4475     align_expr = TREE_OPERAND (align_expr, 0);
4476
4477   if (TREE_CODE (align_expr) != INTEGER_CST)
4478     {
4479       error ("requested alignment is not a constant");
4480       *no_add_attrs = true;
4481     }
4482   else if ((i = tree_log2 (align_expr)) == -1)
4483     {
4484       error ("requested alignment is not a power of 2");
4485       *no_add_attrs = true;
4486     }
4487   else if (i > HOST_BITS_PER_INT - 2)
4488     {
4489       error ("requested alignment is too large");
4490       *no_add_attrs = true;
4491     }
4492   else if (is_type)
4493     {
4494       /* If we have a TYPE_DECL, then copy the type, so that we
4495          don't accidentally modify a builtin type.  See pushdecl.  */
4496       if (decl && TREE_TYPE (decl) != error_mark_node
4497           && DECL_ORIGINAL_TYPE (decl) == NULL_TREE)
4498         {
4499           tree tt = TREE_TYPE (decl);
4500           *type = build_variant_type_copy (*type);
4501           DECL_ORIGINAL_TYPE (decl) = tt;
4502           TYPE_NAME (*type) = decl;
4503           TREE_USED (*type) = TREE_USED (decl);
4504           TREE_TYPE (decl) = *type;
4505         }
4506       else if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
4507         *type = build_variant_type_copy (*type);
4508
4509       TYPE_ALIGN (*type) = (1 << i) * BITS_PER_UNIT;
4510       TYPE_USER_ALIGN (*type) = 1;
4511     }
4512   else if (TREE_CODE (decl) != VAR_DECL
4513            && TREE_CODE (decl) != FIELD_DECL)
4514     {
4515       error ("%Jalignment may not be specified for %qD", decl, decl);
4516       *no_add_attrs = true;
4517     }
4518   else
4519     {
4520       DECL_ALIGN (decl) = (1 << i) * BITS_PER_UNIT;
4521       DECL_USER_ALIGN (decl) = 1;
4522     }
4523
4524   return NULL_TREE;
4525 }
4526
4527 /* Handle a "weak" attribute; arguments as in
4528    struct attribute_spec.handler.  */
4529
4530 static tree
4531 handle_weak_attribute (tree *node, tree ARG_UNUSED (name),
4532                        tree ARG_UNUSED (args),
4533                        int ARG_UNUSED (flags),
4534                        bool * ARG_UNUSED (no_add_attrs))
4535 {
4536   declare_weak (*node);
4537
4538   return NULL_TREE;
4539 }
4540
4541 /* Handle an "alias" attribute; arguments as in
4542    struct attribute_spec.handler.  */
4543
4544 static tree
4545 handle_alias_attribute (tree *node, tree name, tree args,
4546                         int ARG_UNUSED (flags), bool *no_add_attrs)
4547 {
4548   tree decl = *node;
4549
4550   if ((TREE_CODE (decl) == FUNCTION_DECL && DECL_INITIAL (decl))
4551       || (TREE_CODE (decl) != FUNCTION_DECL && ! DECL_EXTERNAL (decl)))
4552     {
4553       error ("%J%qD defined both normally and as an alias", decl, decl);
4554       *no_add_attrs = true;
4555     }
4556
4557   /* Note that the very first time we process a nested declaration,
4558      decl_function_context will not be set.  Indeed, *would* never
4559      be set except for the DECL_INITIAL/DECL_EXTERNAL frobbery that
4560      we do below.  After such frobbery, pushdecl would set the context.
4561      In any case, this is never what we want.  */
4562   else if (decl_function_context (decl) == 0 && current_function_decl == NULL)
4563     {
4564       tree id;
4565
4566       id = TREE_VALUE (args);
4567       if (TREE_CODE (id) != STRING_CST)
4568         {
4569           error ("alias arg not a string");
4570           *no_add_attrs = true;
4571           return NULL_TREE;
4572         }
4573       id = get_identifier (TREE_STRING_POINTER (id));
4574       /* This counts as a use of the object pointed to.  */
4575       TREE_USED (id) = 1;
4576
4577       if (TREE_CODE (decl) == FUNCTION_DECL)
4578         DECL_INITIAL (decl) = error_mark_node;
4579       else
4580         {
4581           DECL_EXTERNAL (decl) = 0;
4582           TREE_STATIC (decl) = 1;
4583         }
4584     }
4585   else
4586     {
4587       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
4588       *no_add_attrs = true;
4589     }
4590
4591   return NULL_TREE;
4592 }
4593
4594 /* Handle an "visibility" attribute; arguments as in
4595    struct attribute_spec.handler.  */
4596
4597 static tree
4598 handle_visibility_attribute (tree *node, tree name, tree args,
4599                              int ARG_UNUSED (flags),
4600                              bool *no_add_attrs)
4601 {
4602   tree decl = *node;
4603   tree id = TREE_VALUE (args);
4604
4605   *no_add_attrs = true;
4606
4607   if (TYPE_P (*node))
4608     {
4609       if (TREE_CODE (*node) != RECORD_TYPE && TREE_CODE (*node) != UNION_TYPE)
4610        {
4611          warning ("%qs attribute ignored on non-class types",
4612                   IDENTIFIER_POINTER (name));
4613          return NULL_TREE;
4614        }
4615     }
4616   else if (decl_function_context (decl) != 0 || ! TREE_PUBLIC (decl))
4617     {
4618       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
4619       return NULL_TREE;
4620     }
4621
4622   if (TREE_CODE (id) != STRING_CST)
4623     {
4624       error ("visibility arg not a string");
4625       return NULL_TREE;
4626     }
4627
4628   /*  If this is a type, set the visibility on the type decl.  */
4629   if (TYPE_P (decl))
4630     {
4631       decl = TYPE_NAME (decl);
4632       if (! decl)
4633         return NULL_TREE;
4634     }
4635
4636   if (strcmp (TREE_STRING_POINTER (id), "default") == 0)
4637     DECL_VISIBILITY (decl) = VISIBILITY_DEFAULT;
4638   else if (strcmp (TREE_STRING_POINTER (id), "internal") == 0)
4639     DECL_VISIBILITY (decl) = VISIBILITY_INTERNAL;
4640   else if (strcmp (TREE_STRING_POINTER (id), "hidden") == 0)
4641     DECL_VISIBILITY (decl) = VISIBILITY_HIDDEN;
4642   else if (strcmp (TREE_STRING_POINTER (id), "protected") == 0)
4643     DECL_VISIBILITY (decl) = VISIBILITY_PROTECTED;
4644   else
4645     error ("visibility arg must be one of \"default\", \"hidden\", \"protected\" or \"internal\"");
4646   DECL_VISIBILITY_SPECIFIED (decl) = 1;
4647
4648   /* For decls only, go ahead and attach the attribute to the node as well.
4649      This is needed so we can determine whether we have VISIBILITY_DEFAULT
4650      because the visibility was not specified, or because it was explicitly
4651      overridden from the class visibility.  */
4652   if (DECL_P (*node))
4653     *no_add_attrs = false;
4654
4655   return NULL_TREE;
4656 }
4657
4658 /* Determine the ELF symbol visibility for DECL, which is either a
4659    variable or a function.  It is an error to use this function if a
4660    definition of DECL is not available in this translation unit.
4661    Returns true if the final visibility has been determined by this
4662    function; false if the caller is free to make additional
4663    modifications.  */
4664
4665 bool
4666 c_determine_visibility (tree decl)
4667 {
4668   gcc_assert (TREE_CODE (decl) == VAR_DECL
4669               || TREE_CODE (decl) == FUNCTION_DECL);
4670
4671   /* If the user explicitly specified the visibility with an
4672      attribute, honor that.  DECL_VISIBILITY will have been set during
4673      the processing of the attribute.  We check for an explicit
4674      attribute, rather than just checking DECL_VISIBILITY_SPECIFIED,
4675      to distinguish the use of an attribute from the use of a "#pragma
4676      GCC visibility push(...)"; in the latter case we still want other
4677      considerations to be able to overrule the #pragma.  */
4678   if (lookup_attribute ("visibility", DECL_ATTRIBUTES (decl)))
4679     return true;
4680
4681   /* Anything that is exported must have default visibility.  */
4682   if (TARGET_DLLIMPORT_DECL_ATTRIBUTES
4683       && lookup_attribute ("dllexport", DECL_ATTRIBUTES (decl)))
4684     {
4685       DECL_VISIBILITY (decl) = VISIBILITY_DEFAULT;
4686       DECL_VISIBILITY_SPECIFIED (decl) = 1;
4687       return true;
4688     }
4689
4690   return false;
4691 }
4692
4693 /* Handle an "tls_model" attribute; arguments as in
4694    struct attribute_spec.handler.  */
4695
4696 static tree
4697 handle_tls_model_attribute (tree *node, tree name, tree args,
4698                             int ARG_UNUSED (flags), bool *no_add_attrs)
4699 {
4700   tree decl = *node;
4701
4702   if (! DECL_THREAD_LOCAL (decl))
4703     {
4704       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
4705       *no_add_attrs = true;
4706     }
4707   else
4708     {
4709       tree id;
4710
4711       id = TREE_VALUE (args);
4712       if (TREE_CODE (id) != STRING_CST)
4713         {
4714           error ("tls_model arg not a string");
4715           *no_add_attrs = true;
4716           return NULL_TREE;
4717         }
4718       if (strcmp (TREE_STRING_POINTER (id), "local-exec")
4719           && strcmp (TREE_STRING_POINTER (id), "initial-exec")
4720           && strcmp (TREE_STRING_POINTER (id), "local-dynamic")
4721           && strcmp (TREE_STRING_POINTER (id), "global-dynamic"))
4722         {
4723           error ("tls_model arg must be one of \"local-exec\", \"initial-exec\", \"local-dynamic\" or \"global-dynamic\"");
4724           *no_add_attrs = true;
4725           return NULL_TREE;
4726         }
4727     }
4728
4729   return NULL_TREE;
4730 }
4731
4732 /* Handle a "no_instrument_function" attribute; arguments as in
4733    struct attribute_spec.handler.  */
4734
4735 static tree
4736 handle_no_instrument_function_attribute (tree *node, tree name,
4737                                          tree ARG_UNUSED (args),
4738                                          int ARG_UNUSED (flags),
4739                                          bool *no_add_attrs)
4740 {
4741   tree decl = *node;
4742
4743   if (TREE_CODE (decl) != FUNCTION_DECL)
4744     {
4745       error ("%J%qE attribute applies only to functions", decl, name);
4746       *no_add_attrs = true;
4747     }
4748   else if (DECL_INITIAL (decl))
4749     {
4750       error ("%Jcan%'t set %qE attribute after definition", decl, name);
4751       *no_add_attrs = true;
4752     }
4753   else
4754     DECL_NO_INSTRUMENT_FUNCTION_ENTRY_EXIT (decl) = 1;
4755
4756   return NULL_TREE;
4757 }
4758
4759 /* Handle a "malloc" attribute; arguments as in
4760    struct attribute_spec.handler.  */
4761
4762 static tree
4763 handle_malloc_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4764                          int ARG_UNUSED (flags), bool *no_add_attrs)
4765 {
4766   if (TREE_CODE (*node) == FUNCTION_DECL)
4767     DECL_IS_MALLOC (*node) = 1;
4768   /* ??? TODO: Support types.  */
4769   else
4770     {
4771       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
4772       *no_add_attrs = true;
4773     }
4774
4775   return NULL_TREE;
4776 }
4777
4778 /* Handle a "no_limit_stack" attribute; arguments as in
4779    struct attribute_spec.handler.  */
4780
4781 static tree
4782 handle_no_limit_stack_attribute (tree *node, tree name,
4783                                  tree ARG_UNUSED (args),
4784                                  int ARG_UNUSED (flags),
4785                                  bool *no_add_attrs)
4786 {
4787   tree decl = *node;
4788
4789   if (TREE_CODE (decl) != FUNCTION_DECL)
4790     {
4791       error ("%J%qE attribute applies only to functions", decl, name);
4792       *no_add_attrs = true;
4793     }
4794   else if (DECL_INITIAL (decl))
4795     {
4796       error ("%Jcan%'t set %qE attribute after definition", decl, name);
4797       *no_add_attrs = true;
4798     }
4799   else
4800     DECL_NO_LIMIT_STACK (decl) = 1;
4801
4802   return NULL_TREE;
4803 }
4804
4805 /* Handle a "pure" attribute; arguments as in
4806    struct attribute_spec.handler.  */
4807
4808 static tree
4809 handle_pure_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4810                        int ARG_UNUSED (flags), bool *no_add_attrs)
4811 {
4812   if (TREE_CODE (*node) == FUNCTION_DECL)
4813     DECL_IS_PURE (*node) = 1;
4814   /* ??? TODO: Support types.  */
4815   else
4816     {
4817       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
4818       *no_add_attrs = true;
4819     }
4820
4821   return NULL_TREE;
4822 }
4823
4824 /* Handle a "deprecated" attribute; arguments as in
4825    struct attribute_spec.handler.  */
4826
4827 static tree
4828 handle_deprecated_attribute (tree *node, tree name,
4829                              tree ARG_UNUSED (args), int flags,
4830                              bool *no_add_attrs)
4831 {
4832   tree type = NULL_TREE;
4833   int warn = 0;
4834   const char *what = NULL;
4835
4836   if (DECL_P (*node))
4837     {
4838       tree decl = *node;
4839       type = TREE_TYPE (decl);
4840
4841       if (TREE_CODE (decl) == TYPE_DECL
4842           || TREE_CODE (decl) == PARM_DECL
4843           || TREE_CODE (decl) == VAR_DECL
4844           || TREE_CODE (decl) == FUNCTION_DECL
4845           || TREE_CODE (decl) == FIELD_DECL)
4846         TREE_DEPRECATED (decl) = 1;
4847       else
4848         warn = 1;
4849     }
4850   else if (TYPE_P (*node))
4851     {
4852       if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
4853         *node = build_variant_type_copy (*node);
4854       TREE_DEPRECATED (*node) = 1;
4855       type = *node;
4856     }
4857   else
4858     warn = 1;
4859
4860   if (warn)
4861     {
4862       *no_add_attrs = true;
4863       if (type && TYPE_NAME (type))
4864         {
4865           if (TREE_CODE (TYPE_NAME (type)) == IDENTIFIER_NODE)
4866             what = IDENTIFIER_POINTER (TYPE_NAME (*node));
4867           else if (TREE_CODE (TYPE_NAME (type)) == TYPE_DECL
4868                    && DECL_NAME (TYPE_NAME (type)))
4869             what = IDENTIFIER_POINTER (DECL_NAME (TYPE_NAME (type)));
4870         }
4871       if (what)
4872         warning ("%qs attribute ignored for %qs",
4873                   IDENTIFIER_POINTER (name), what);
4874       else
4875         warning ("%qs attribute ignored",
4876                       IDENTIFIER_POINTER (name));
4877     }
4878
4879   return NULL_TREE;
4880 }
4881
4882 /* Handle a "vector_size" attribute; arguments as in
4883    struct attribute_spec.handler.  */
4884
4885 static tree
4886 handle_vector_size_attribute (tree *node, tree name, tree args,
4887                               int ARG_UNUSED (flags),
4888                               bool *no_add_attrs)
4889 {
4890   unsigned HOST_WIDE_INT vecsize, nunits;
4891   enum machine_mode orig_mode;
4892   tree type = *node, new_type, size;
4893
4894   *no_add_attrs = true;
4895
4896   /* Stripping NON_LVALUE_EXPR allows declarations such as
4897      typedef short v4si __attribute__((vector_size (4 * sizeof(short)))).  */
4898   size = TREE_VALUE (args);
4899   if (TREE_CODE (size) == NON_LVALUE_EXPR)
4900     size = TREE_OPERAND (size, 0);
4901
4902   if (! host_integerp (size, 1))
4903     {
4904       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
4905       return NULL_TREE;
4906     }
4907
4908   /* Get the vector size (in bytes).  */
4909   vecsize = tree_low_cst (size, 1);
4910
4911   /* We need to provide for vector pointers, vector arrays, and
4912      functions returning vectors.  For example:
4913
4914        __attribute__((vector_size(16))) short *foo;
4915
4916      In this case, the mode is SI, but the type being modified is
4917      HI, so we need to look further.  */
4918
4919   while (POINTER_TYPE_P (type)
4920          || TREE_CODE (type) == FUNCTION_TYPE
4921          || TREE_CODE (type) == METHOD_TYPE
4922          || TREE_CODE (type) == ARRAY_TYPE)
4923     type = TREE_TYPE (type);
4924
4925   /* Get the mode of the type being modified.  */
4926   orig_mode = TYPE_MODE (type);
4927
4928   if (TREE_CODE (type) == RECORD_TYPE
4929       || (GET_MODE_CLASS (orig_mode) != MODE_FLOAT
4930           && GET_MODE_CLASS (orig_mode) != MODE_INT)
4931       || ! host_integerp (TYPE_SIZE_UNIT (type), 1))
4932     {
4933       error ("invalid vector type for attribute %qs",
4934              IDENTIFIER_POINTER (name));
4935       return NULL_TREE;
4936     }
4937
4938   /* Calculate how many units fit in the vector.  */
4939   nunits = vecsize / tree_low_cst (TYPE_SIZE_UNIT (type), 1);
4940   if (nunits & (nunits - 1))
4941     {
4942       error ("number of components of the vector not a power of two");
4943       return NULL_TREE;
4944     }
4945
4946   new_type = build_vector_type (type, nunits);
4947
4948   /* Build back pointers if needed.  */
4949   *node = reconstruct_complex_type (*node, new_type);
4950
4951   return NULL_TREE;
4952 }
4953
4954 /* Handle the "nonnull" attribute.  */
4955 static tree
4956 handle_nonnull_attribute (tree *node, tree ARG_UNUSED (name),
4957                           tree args, int ARG_UNUSED (flags),
4958                           bool *no_add_attrs)
4959 {
4960   tree type = *node;
4961   unsigned HOST_WIDE_INT attr_arg_num;
4962
4963   /* If no arguments are specified, all pointer arguments should be
4964      non-null.  Verify a full prototype is given so that the arguments
4965      will have the correct types when we actually check them later.  */
4966   if (! args)
4967     {
4968       if (! TYPE_ARG_TYPES (type))
4969         {
4970           error ("nonnull attribute without arguments on a non-prototype");
4971           *no_add_attrs = true;
4972         }
4973       return NULL_TREE;
4974     }
4975
4976   /* Argument list specified.  Verify that each argument number references
4977      a pointer argument.  */
4978   for (attr_arg_num = 1; args; args = TREE_CHAIN (args))
4979     {
4980       tree argument;
4981       unsigned HOST_WIDE_INT arg_num = 0, ck_num;
4982
4983       if (! get_nonnull_operand (TREE_VALUE (args), &arg_num))
4984         {
4985           error ("nonnull argument has invalid operand number (arg %lu)",
4986                  (unsigned long) attr_arg_num);
4987           *no_add_attrs = true;
4988           return NULL_TREE;
4989         }
4990
4991       argument = TYPE_ARG_TYPES (type);
4992       if (argument)
4993         {
4994           for (ck_num = 1; ; ck_num++)
4995             {
4996               if (! argument || ck_num == arg_num)
4997                 break;
4998               argument = TREE_CHAIN (argument);
4999             }
5000
5001           if (! argument
5002               || TREE_CODE (TREE_VALUE (argument)) == VOID_TYPE)
5003             {
5004               error ("nonnull argument with out-of-range operand number (arg %lu, operand %lu)",
5005                      (unsigned long) attr_arg_num, (unsigned long) arg_num);
5006               *no_add_attrs = true;
5007               return NULL_TREE;
5008             }
5009
5010           if (TREE_CODE (TREE_VALUE (argument)) != POINTER_TYPE)
5011             {
5012               error ("nonnull argument references non-pointer operand (arg %lu, operand %lu)",
5013                    (unsigned long) attr_arg_num, (unsigned long) arg_num);
5014               *no_add_attrs = true;
5015               return NULL_TREE;
5016             }
5017         }
5018     }
5019
5020   return NULL_TREE;
5021 }
5022
5023 /* Check the argument list of a function call for null in argument slots
5024    that are marked as requiring a non-null pointer argument.  */
5025
5026 static void
5027 check_function_nonnull (tree attrs, tree params)
5028 {
5029   tree a, args, param;
5030   int param_num;
5031
5032   for (a = attrs; a; a = TREE_CHAIN (a))
5033     {
5034       if (is_attribute_p ("nonnull", TREE_PURPOSE (a)))
5035         {
5036           args = TREE_VALUE (a);
5037
5038           /* Walk the argument list.  If we encounter an argument number we
5039              should check for non-null, do it.  If the attribute has no args,
5040              then every pointer argument is checked (in which case the check
5041              for pointer type is done in check_nonnull_arg).  */
5042           for (param = params, param_num = 1; ;
5043                param_num++, param = TREE_CHAIN (param))
5044             {
5045               if (! param)
5046         break;
5047               if (! args || nonnull_check_p (args, param_num))
5048         check_function_arguments_recurse (check_nonnull_arg, NULL,
5049                                           TREE_VALUE (param),
5050                                           param_num);
5051             }
5052         }
5053     }
5054 }
5055
5056 /* Check that the Nth argument of a function call (counting backwards
5057    from the end) is a (pointer)0.  */
5058
5059 static void
5060 check_function_sentinel (tree attrs, tree params)
5061 {
5062   tree attr = lookup_attribute ("sentinel", attrs);
5063
5064   if (attr)
5065     {
5066       if (!params)
5067         warning ("missing sentinel in function call");
5068       else
5069         {
5070           tree sentinel, end;
5071           unsigned pos = 0;
5072
5073           if (TREE_VALUE (attr))
5074             {
5075               tree p = TREE_VALUE (TREE_VALUE (attr));
5076               STRIP_NOPS (p);
5077               pos = TREE_INT_CST_LOW (p);
5078             }
5079
5080           sentinel = end = params;
5081
5082           /* Advance `end' ahead of `sentinel' by `pos' positions.  */
5083           while (pos > 0 && TREE_CHAIN (end))
5084             {
5085               pos--;
5086               end = TREE_CHAIN (end);
5087             }
5088           if (pos > 0)
5089             {
5090               warning ("not enough arguments to fit a sentinel");
5091               return;
5092             }
5093
5094           /* Now advance both until we find the last parameter.  */
5095           while (TREE_CHAIN (end))
5096             {
5097               end = TREE_CHAIN (end);
5098               sentinel = TREE_CHAIN (sentinel);
5099             }
5100
5101           /* Validate the sentinel.  */
5102           if (!POINTER_TYPE_P (TREE_TYPE (TREE_VALUE (sentinel)))
5103               || !integer_zerop (TREE_VALUE (sentinel)))
5104             warning ("missing sentinel in function call");
5105         }
5106     }
5107 }
5108
5109 /* Helper for check_function_nonnull; given a list of operands which
5110    must be non-null in ARGS, determine if operand PARAM_NUM should be
5111    checked.  */
5112
5113 static bool
5114 nonnull_check_p (tree args, unsigned HOST_WIDE_INT param_num)
5115 {
5116   unsigned HOST_WIDE_INT arg_num = 0;
5117
5118   for (; args; args = TREE_CHAIN (args))
5119     {
5120       bool found = get_nonnull_operand (TREE_VALUE (args), &arg_num);
5121
5122       gcc_assert (found);
5123
5124       if (arg_num == param_num)
5125         return true;
5126     }
5127   return false;
5128 }
5129
5130 /* Check that the function argument PARAM (which is operand number
5131    PARAM_NUM) is non-null.  This is called by check_function_nonnull
5132    via check_function_arguments_recurse.  */
5133
5134 static void
5135 check_nonnull_arg (void * ARG_UNUSED (ctx), tree param,
5136                    unsigned HOST_WIDE_INT param_num)
5137 {
5138   /* Just skip checking the argument if it's not a pointer.  This can
5139      happen if the "nonnull" attribute was given without an operand
5140      list (which means to check every pointer argument).  */
5141
5142   if (TREE_CODE (TREE_TYPE (param)) != POINTER_TYPE)
5143     return;
5144
5145   if (integer_zerop (param))
5146     warning ("null argument where non-null required (arg %lu)",
5147              (unsigned long) param_num);
5148 }
5149
5150 /* Helper for nonnull attribute handling; fetch the operand number
5151    from the attribute argument list.  */
5152
5153 static bool
5154 get_nonnull_operand (tree arg_num_expr, unsigned HOST_WIDE_INT *valp)
5155 {
5156   /* Strip any conversions from the arg number and verify they
5157      are constants.  */
5158   while (TREE_CODE (arg_num_expr) == NOP_EXPR
5159          || TREE_CODE (arg_num_expr) == CONVERT_EXPR
5160          || TREE_CODE (arg_num_expr) == NON_LVALUE_EXPR)
5161     arg_num_expr = TREE_OPERAND (arg_num_expr, 0);
5162
5163   if (TREE_CODE (arg_num_expr) != INTEGER_CST
5164       || TREE_INT_CST_HIGH (arg_num_expr) != 0)
5165     return false;
5166
5167   *valp = TREE_INT_CST_LOW (arg_num_expr);
5168   return true;
5169 }
5170
5171 /* Handle a "nothrow" attribute; arguments as in
5172    struct attribute_spec.handler.  */
5173
5174 static tree
5175 handle_nothrow_attribute (tree *node, tree name, tree ARG_UNUSED (args),
5176                           int ARG_UNUSED (flags), bool *no_add_attrs)
5177 {
5178   if (TREE_CODE (*node) == FUNCTION_DECL)
5179     TREE_NOTHROW (*node) = 1;
5180   /* ??? TODO: Support types.  */
5181   else
5182     {
5183       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
5184       *no_add_attrs = true;
5185     }
5186
5187   return NULL_TREE;
5188 }
5189
5190 /* Handle a "cleanup" attribute; arguments as in
5191    struct attribute_spec.handler.  */
5192
5193 static tree
5194 handle_cleanup_attribute (tree *node, tree name, tree args,
5195                           int ARG_UNUSED (flags), bool *no_add_attrs)
5196 {
5197   tree decl = *node;
5198   tree cleanup_id, cleanup_decl;
5199
5200   /* ??? Could perhaps support cleanups on TREE_STATIC, much like we do
5201      for global destructors in C++.  This requires infrastructure that
5202      we don't have generically at the moment.  It's also not a feature
5203      we'd be missing too much, since we do have attribute constructor.  */
5204   if (TREE_CODE (decl) != VAR_DECL || TREE_STATIC (decl))
5205     {
5206       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
5207       *no_add_attrs = true;
5208       return NULL_TREE;
5209     }
5210
5211   /* Verify that the argument is a function in scope.  */
5212   /* ??? We could support pointers to functions here as well, if
5213      that was considered desirable.  */
5214   cleanup_id = TREE_VALUE (args);
5215   if (TREE_CODE (cleanup_id) != IDENTIFIER_NODE)
5216     {
5217       error ("cleanup arg not an identifier");
5218       *no_add_attrs = true;
5219       return NULL_TREE;
5220     }
5221   cleanup_decl = lookup_name (cleanup_id);
5222   if (!cleanup_decl || TREE_CODE (cleanup_decl) != FUNCTION_DECL)
5223     {
5224       error ("cleanup arg not a function");
5225       *no_add_attrs = true;
5226       return NULL_TREE;
5227     }
5228
5229   /* That the function has proper type is checked with the
5230      eventual call to build_function_call.  */
5231
5232   return NULL_TREE;
5233 }
5234
5235 /* Handle a "warn_unused_result" attribute.  No special handling.  */
5236
5237 static tree
5238 handle_warn_unused_result_attribute (tree *node, tree name,
5239                                tree ARG_UNUSED (args),
5240                                int ARG_UNUSED (flags), bool *no_add_attrs)
5241 {
5242   /* Ignore the attribute for functions not returning any value.  */
5243   if (VOID_TYPE_P (TREE_TYPE (*node)))
5244     {
5245       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
5246       *no_add_attrs = true;
5247     }
5248
5249   return NULL_TREE;
5250 }
5251
5252 /* Handle a "sentinel" attribute.  */
5253
5254 static tree
5255 handle_sentinel_attribute (tree *node, tree name, tree args,
5256                            int ARG_UNUSED (flags), bool *no_add_attrs)
5257 {
5258   tree params = TYPE_ARG_TYPES (*node);
5259
5260   if (!params)
5261     {
5262       warning ("%qs attribute requires prototypes with named arguments",
5263                IDENTIFIER_POINTER (name));
5264       *no_add_attrs = true;
5265     }
5266   else
5267     {
5268       while (TREE_CHAIN (params))
5269         params = TREE_CHAIN (params);
5270
5271       if (VOID_TYPE_P (TREE_VALUE (params)))
5272         {
5273           warning ("%qs attribute only applies to variadic functions",
5274                    IDENTIFIER_POINTER (name));
5275           *no_add_attrs = true;
5276         }
5277     }
5278
5279   if (args)
5280     {
5281       tree position = TREE_VALUE (args);
5282
5283       STRIP_NOPS (position);
5284       if (TREE_CODE (position) != INTEGER_CST)
5285         {
5286           warning ("requested position is not an integer constant");
5287           *no_add_attrs = true;
5288         }
5289       else
5290         {
5291           if (tree_int_cst_lt (position, integer_zero_node))
5292             {
5293               warning ("requested position is less than zero");
5294               *no_add_attrs = true;
5295             }
5296         }
5297     }
5298
5299   return NULL_TREE;
5300 }
5301 \f
5302 /* Check for valid arguments being passed to a function.  */
5303 void
5304 check_function_arguments (tree attrs, tree params)
5305 {
5306   /* Check for null being passed in a pointer argument that must be
5307      non-null.  We also need to do this if format checking is enabled.  */
5308
5309   if (warn_nonnull)
5310     check_function_nonnull (attrs, params);
5311
5312   /* Check for errors in format strings.  */
5313
5314   if (warn_format)
5315     {
5316       check_function_format (attrs, params);
5317       check_function_sentinel (attrs, params);
5318     }
5319 }
5320
5321 /* Generic argument checking recursion routine.  PARAM is the argument to
5322    be checked.  PARAM_NUM is the number of the argument.  CALLBACK is invoked
5323    once the argument is resolved.  CTX is context for the callback.  */
5324 void
5325 check_function_arguments_recurse (void (*callback)
5326                                   (void *, tree, unsigned HOST_WIDE_INT),
5327                                   void *ctx, tree param,
5328                                   unsigned HOST_WIDE_INT param_num)
5329 {
5330   if (TREE_CODE (param) == NOP_EXPR)
5331     {
5332       /* Strip coercion.  */
5333       check_function_arguments_recurse (callback, ctx,
5334                                         TREE_OPERAND (param, 0), param_num);
5335       return;
5336     }
5337
5338   if (TREE_CODE (param) == CALL_EXPR)
5339     {
5340       tree type = TREE_TYPE (TREE_TYPE (TREE_OPERAND (param, 0)));
5341       tree attrs;
5342       bool found_format_arg = false;
5343
5344       /* See if this is a call to a known internationalization function
5345          that modifies a format arg.  Such a function may have multiple
5346          format_arg attributes (for example, ngettext).  */
5347
5348       for (attrs = TYPE_ATTRIBUTES (type);
5349            attrs;
5350            attrs = TREE_CHAIN (attrs))
5351         if (is_attribute_p ("format_arg", TREE_PURPOSE (attrs)))
5352           {
5353             tree inner_args;
5354             tree format_num_expr;
5355             int format_num;
5356             int i;
5357
5358             /* Extract the argument number, which was previously checked
5359                to be valid.  */
5360             format_num_expr = TREE_VALUE (TREE_VALUE (attrs));
5361             while (TREE_CODE (format_num_expr) == NOP_EXPR
5362                    || TREE_CODE (format_num_expr) == CONVERT_EXPR
5363                    || TREE_CODE (format_num_expr) == NON_LVALUE_EXPR)
5364               format_num_expr = TREE_OPERAND (format_num_expr, 0);
5365
5366             gcc_assert (TREE_CODE (format_num_expr) == INTEGER_CST
5367                         && !TREE_INT_CST_HIGH (format_num_expr));
5368
5369             format_num = TREE_INT_CST_LOW (format_num_expr);
5370
5371             for (inner_args = TREE_OPERAND (param, 1), i = 1;
5372                  inner_args != 0;
5373                  inner_args = TREE_CHAIN (inner_args), i++)
5374               if (i == format_num)
5375                 {
5376                   check_function_arguments_recurse (callback, ctx,
5377                                                     TREE_VALUE (inner_args),
5378                                                     param_num);
5379                   found_format_arg = true;
5380                   break;
5381                 }
5382           }
5383
5384       /* If we found a format_arg attribute and did a recursive check,
5385          we are done with checking this argument.  Otherwise, we continue
5386          and this will be considered a non-literal.  */
5387       if (found_format_arg)
5388         return;
5389     }
5390
5391   if (TREE_CODE (param) == COND_EXPR)
5392     {
5393       /* Check both halves of the conditional expression.  */
5394       check_function_arguments_recurse (callback, ctx,
5395                                         TREE_OPERAND (param, 1), param_num);
5396       check_function_arguments_recurse (callback, ctx,
5397                                         TREE_OPERAND (param, 2), param_num);
5398       return;
5399     }
5400
5401   (*callback) (ctx, param, param_num);
5402 }
5403
5404 /* Function to help qsort sort FIELD_DECLs by name order.  */
5405
5406 int
5407 field_decl_cmp (const void *x_p, const void *y_p)
5408 {
5409   const tree *const x = (const tree *const) x_p;
5410   const tree *const y = (const tree *const) y_p;
5411
5412   if (DECL_NAME (*x) == DECL_NAME (*y))
5413     /* A nontype is "greater" than a type.  */
5414     return (TREE_CODE (*y) == TYPE_DECL) - (TREE_CODE (*x) == TYPE_DECL);
5415   if (DECL_NAME (*x) == NULL_TREE)
5416     return -1;
5417   if (DECL_NAME (*y) == NULL_TREE)
5418     return 1;
5419   if (DECL_NAME (*x) < DECL_NAME (*y))
5420     return -1;
5421   return 1;
5422 }
5423
5424 static struct {
5425   gt_pointer_operator new_value;
5426   void *cookie;
5427 } resort_data;
5428
5429 /* This routine compares two fields like field_decl_cmp but using the
5430 pointer operator in resort_data.  */
5431
5432 static int
5433 resort_field_decl_cmp (const void *x_p, const void *y_p)
5434 {
5435   const tree *const x = (const tree *const) x_p;
5436   const tree *const y = (const tree *const) y_p;
5437
5438   if (DECL_NAME (*x) == DECL_NAME (*y))
5439     /* A nontype is "greater" than a type.  */
5440     return (TREE_CODE (*y) == TYPE_DECL) - (TREE_CODE (*x) == TYPE_DECL);
5441   if (DECL_NAME (*x) == NULL_TREE)
5442     return -1;
5443   if (DECL_NAME (*y) == NULL_TREE)
5444     return 1;
5445   {
5446     tree d1 = DECL_NAME (*x);
5447     tree d2 = DECL_NAME (*y);
5448     resort_data.new_value (&d1, resort_data.cookie);
5449     resort_data.new_value (&d2, resort_data.cookie);
5450     if (d1 < d2)
5451       return -1;
5452   }
5453   return 1;
5454 }
5455
5456 /* Resort DECL_SORTED_FIELDS because pointers have been reordered.  */
5457
5458 void
5459 resort_sorted_fields (void *obj,
5460                       void * ARG_UNUSED (orig_obj),
5461                       gt_pointer_operator new_value,
5462                       void *cookie)
5463 {
5464   struct sorted_fields_type *sf = (struct sorted_fields_type *) obj;
5465   resort_data.new_value = new_value;
5466   resort_data.cookie = cookie;
5467   qsort (&sf->elts[0], sf->len, sizeof (tree),
5468          resort_field_decl_cmp);
5469 }
5470
5471 /* Issue the error given by MSGID, indicating that it occurred before
5472    TOKEN, which had the associated VALUE.  */
5473
5474 void
5475 c_parse_error (const char *msgid, enum cpp_ttype token, tree value)
5476 {
5477   const char *string = _(msgid);
5478
5479   if (token == CPP_EOF)
5480     error ("%s at end of input", string);
5481   else if (token == CPP_CHAR || token == CPP_WCHAR)
5482     {
5483       unsigned int val = TREE_INT_CST_LOW (value);
5484       const char *const ell = (token == CPP_CHAR) ? "" : "L";
5485       if (val <= UCHAR_MAX && ISGRAPH (val))
5486         error ("%s before %s'%c'", string, ell, val);
5487       else
5488         error ("%s before %s'\\x%x'", string, ell, val);
5489     }
5490   else if (token == CPP_STRING
5491            || token == CPP_WSTRING)
5492     error ("%s before string constant", string);
5493   else if (token == CPP_NUMBER)
5494     error ("%s before numeric constant", string);
5495   else if (token == CPP_NAME)
5496     error ("%s before \"%s\"", string, IDENTIFIER_POINTER (value));
5497   else if (token < N_TTYPES)
5498     error ("%s before %qs token", string, cpp_type2name (token));
5499   else
5500     error ("%s", string);
5501 }
5502
5503 /* Walk a gimplified function and warn for functions whose return value is
5504    ignored and attribute((warn_unused_result)) is set.  This is done before
5505    inlining, so we don't have to worry about that.  */
5506
5507 void
5508 c_warn_unused_result (tree *top_p)
5509 {
5510   tree t = *top_p;
5511   tree_stmt_iterator i;
5512   tree fdecl, ftype;
5513
5514   switch (TREE_CODE (t))
5515     {
5516     case STATEMENT_LIST:
5517       for (i = tsi_start (*top_p); !tsi_end_p (i); tsi_next (&i))
5518         c_warn_unused_result (tsi_stmt_ptr (i));
5519       break;
5520
5521     case COND_EXPR:
5522       c_warn_unused_result (&COND_EXPR_THEN (t));
5523       c_warn_unused_result (&COND_EXPR_ELSE (t));
5524       break;
5525     case BIND_EXPR:
5526       c_warn_unused_result (&BIND_EXPR_BODY (t));
5527       break;
5528     case TRY_FINALLY_EXPR:
5529     case TRY_CATCH_EXPR:
5530       c_warn_unused_result (&TREE_OPERAND (t, 0));
5531       c_warn_unused_result (&TREE_OPERAND (t, 1));
5532       break;
5533     case CATCH_EXPR:
5534       c_warn_unused_result (&CATCH_BODY (t));
5535       break;
5536     case EH_FILTER_EXPR:
5537       c_warn_unused_result (&EH_FILTER_FAILURE (t));
5538       break;
5539
5540     case CALL_EXPR:
5541       if (TREE_USED (t))
5542         break;
5543
5544       /* This is a naked call, as opposed to a CALL_EXPR nested inside
5545          a MODIFY_EXPR.  All calls whose value is ignored should be
5546          represented like this.  Look for the attribute.  */
5547       fdecl = get_callee_fndecl (t);
5548       if (fdecl)
5549         ftype = TREE_TYPE (fdecl);
5550       else
5551         {
5552           ftype = TREE_TYPE (TREE_OPERAND (t, 0));
5553           /* Look past pointer-to-function to the function type itself.  */
5554           ftype = TREE_TYPE (ftype);
5555         }
5556
5557       if (lookup_attribute ("warn_unused_result", TYPE_ATTRIBUTES (ftype)))
5558         {
5559           if (fdecl)
5560             warning ("%Hignoring return value of %qD, "
5561                      "declared with attribute warn_unused_result",
5562                      EXPR_LOCUS (t), fdecl);
5563           else
5564             warning ("%Hignoring return value of function "
5565                      "declared with attribute warn_unused_result",
5566                      EXPR_LOCUS (t));
5567         }
5568       break;
5569
5570     default:
5571       /* Not a container, not a call, or a call whose value is used.  */
5572       break;
5573     }
5574 }
5575
5576 /* Build the result of __builtin_offsetof.  EXPR is a nested sequence of
5577    component references, with an INDIRECT_REF at the bottom; much like
5578    the traditional rendering of offsetof as a macro.  Returns the folded
5579    and properly cast result.  */
5580
5581 static tree
5582 fold_offsetof_1 (tree expr)
5583 {
5584   enum tree_code code = PLUS_EXPR;
5585   tree base, off, t;
5586
5587   switch (TREE_CODE (expr))
5588     {
5589     case ERROR_MARK:
5590       return expr;
5591
5592     case INDIRECT_REF:
5593       return size_zero_node;
5594
5595     case COMPONENT_REF:
5596       base = fold_offsetof_1 (TREE_OPERAND (expr, 0));
5597       if (base == error_mark_node)
5598         return base;
5599
5600       t = TREE_OPERAND (expr, 1);
5601       if (DECL_C_BIT_FIELD (t))
5602         {
5603           error ("attempt to take address of bit-field structure "
5604                  "member %qs", IDENTIFIER_POINTER (DECL_NAME (t)));
5605           return error_mark_node;
5606         }
5607       off = size_binop (PLUS_EXPR, DECL_FIELD_OFFSET (t),
5608                         size_int (tree_low_cst (DECL_FIELD_BIT_OFFSET (t), 1)
5609                                   / BITS_PER_UNIT));
5610       break;
5611
5612     case ARRAY_REF:
5613       base = fold_offsetof_1 (TREE_OPERAND (expr, 0));
5614       if (base == error_mark_node)
5615         return base;
5616
5617       t = TREE_OPERAND (expr, 1);
5618       if (TREE_CODE (t) == INTEGER_CST && tree_int_cst_sgn (t) < 0)
5619         {
5620           code = MINUS_EXPR;
5621           t = fold (build1 (NEGATE_EXPR, TREE_TYPE (t), t));
5622         }
5623       t = convert (sizetype, t);
5624       off = size_binop (MULT_EXPR, TYPE_SIZE_UNIT (TREE_TYPE (expr)), t);
5625       break;
5626
5627     default:
5628       gcc_unreachable ();
5629     }
5630
5631   return size_binop (code, base, off);
5632 }
5633
5634 tree
5635 fold_offsetof (tree expr)
5636 {
5637   /* Convert back from the internal sizetype to size_t.  */
5638   return convert (size_type_node, fold_offsetof_1 (expr));
5639 }
5640
5641 #include "gt-c-common.h"