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 static GTY((param_is (union tree_node))) htab_t type_hash_table;
2596
2597 /* Return the typed-based alias set for T, which may be an expression
2598    or a type.  Return -1 if we don't do anything special.  */
2599
2600 HOST_WIDE_INT
2601 c_common_get_alias_set (tree t)
2602 {
2603   tree u;
2604   PTR *slot;
2605
2606   /* Permit type-punning when accessing a union, provided the access
2607      is directly through the union.  For example, this code does not
2608      permit taking the address of a union member and then storing
2609      through it.  Even the type-punning allowed here is a GCC
2610      extension, albeit a common and useful one; the C standard says
2611      that such accesses have implementation-defined behavior.  */
2612   for (u = t;
2613        TREE_CODE (u) == COMPONENT_REF || TREE_CODE (u) == ARRAY_REF;
2614        u = TREE_OPERAND (u, 0))
2615     if (TREE_CODE (u) == COMPONENT_REF
2616         && TREE_CODE (TREE_TYPE (TREE_OPERAND (u, 0))) == UNION_TYPE)
2617       return 0;
2618
2619   /* That's all the expressions we handle specially.  */
2620   if (!TYPE_P (t))
2621     return -1;
2622
2623   /* The C standard guarantees that any object may be accessed via an
2624      lvalue that has character type.  */
2625   if (t == char_type_node
2626       || t == signed_char_type_node
2627       || t == unsigned_char_type_node)
2628     return 0;
2629
2630   /* If it has the may_alias attribute, it can alias anything.  */
2631   if (lookup_attribute ("may_alias", TYPE_ATTRIBUTES (t)))
2632     return 0;
2633
2634   /* The C standard specifically allows aliasing between signed and
2635      unsigned variants of the same type.  We treat the signed
2636      variant as canonical.  */
2637   if (TREE_CODE (t) == INTEGER_TYPE && TYPE_UNSIGNED (t))
2638     {
2639       tree t1 = c_common_signed_type (t);
2640
2641       /* t1 == t can happen for boolean nodes which are always unsigned.  */
2642       if (t1 != t)
2643         return get_alias_set (t1);
2644     }
2645   else if (POINTER_TYPE_P (t))
2646     {
2647       tree t1;
2648
2649       /* Unfortunately, there is no canonical form of a pointer type.
2650          In particular, if we have `typedef int I', then `int *', and
2651          `I *' are different types.  So, we have to pick a canonical
2652          representative.  We do this below.
2653
2654          Technically, this approach is actually more conservative that
2655          it needs to be.  In particular, `const int *' and `int *'
2656          should be in different alias sets, according to the C and C++
2657          standard, since their types are not the same, and so,
2658          technically, an `int **' and `const int **' cannot point at
2659          the same thing.
2660
2661          But, the standard is wrong.  In particular, this code is
2662          legal C++:
2663
2664             int *ip;
2665             int **ipp = &ip;
2666             const int* const* cipp = ipp;
2667
2668          And, it doesn't make sense for that to be legal unless you
2669          can dereference IPP and CIPP.  So, we ignore cv-qualifiers on
2670          the pointed-to types.  This issue has been reported to the
2671          C++ committee.  */
2672       t1 = build_type_no_quals (t);
2673       if (t1 != t)
2674         return get_alias_set (t1);
2675     }
2676
2677   /* Handle the case of multiple type nodes referring to "the same" type,
2678      which occurs with IMA.  These share an alias set.  FIXME:  Currently only
2679      C90 is handled.  (In C99 type compatibility is not transitive, which
2680      complicates things mightily. The alias set splay trees can theoretically
2681      represent this, but insertion is tricky when you consider all the
2682      different orders things might arrive in.) */
2683
2684   if (c_language != clk_c || flag_isoc99)
2685     return -1;
2686
2687   /* Save time if there's only one input file.  */
2688   if (num_in_fnames == 1)
2689     return -1;
2690
2691   /* Pointers need special handling if they point to any type that
2692      needs special handling (below).  */
2693   if (TREE_CODE (t) == POINTER_TYPE)
2694     {
2695       tree t2;
2696       /* Find bottom type under any nested POINTERs.  */
2697       for (t2 = TREE_TYPE (t);
2698      TREE_CODE (t2) == POINTER_TYPE;
2699      t2 = TREE_TYPE (t2))
2700   ;
2701       if (TREE_CODE (t2) != RECORD_TYPE
2702     && TREE_CODE (t2) != ENUMERAL_TYPE
2703     && TREE_CODE (t2) != QUAL_UNION_TYPE
2704     && TREE_CODE (t2) != UNION_TYPE)
2705   return -1;
2706       if (TYPE_SIZE (t2) == 0)
2707   return -1;
2708     }
2709   /* These are the only cases that need special handling.  */
2710   if (TREE_CODE (t) != RECORD_TYPE
2711       && TREE_CODE (t) != ENUMERAL_TYPE
2712       && TREE_CODE (t) != QUAL_UNION_TYPE
2713       && TREE_CODE (t) != UNION_TYPE
2714       && TREE_CODE (t) != POINTER_TYPE)
2715     return -1;
2716   /* Undefined? */
2717   if (TYPE_SIZE (t) == 0)
2718     return -1;
2719
2720   /* Look up t in hash table.  Only one of the compatible types within each
2721      alias set is recorded in the table.  */
2722   if (!type_hash_table)
2723     type_hash_table = htab_create_ggc (1021, c_type_hash,
2724             (htab_eq) lang_hooks.types_compatible_p,
2725             NULL);
2726   slot = htab_find_slot (type_hash_table, t, INSERT);
2727   if (*slot != NULL)
2728     {
2729       TYPE_ALIAS_SET (t) = TYPE_ALIAS_SET ((tree)*slot);
2730       return TYPE_ALIAS_SET ((tree)*slot);
2731     }
2732   else
2733     /* Our caller will assign and record (in t) a new alias set; all we need
2734        to do is remember t in the hash table.  */
2735     *slot = t;
2736
2737   return -1;
2738 }
2739 \f
2740 /* Compute the value of 'sizeof (TYPE)' or '__alignof__ (TYPE)', where the
2741    second parameter indicates which OPERATOR is being applied.  The COMPLAIN
2742    flag controls whether we should diagnose possibly ill-formed
2743    constructs or not.  */
2744 tree
2745 c_sizeof_or_alignof_type (tree type, enum tree_code op, int complain)
2746 {
2747   const char *op_name;
2748   tree value = NULL;
2749   enum tree_code type_code = TREE_CODE (type);
2750
2751   gcc_assert (op == SIZEOF_EXPR || op == ALIGNOF_EXPR);
2752   op_name = op == SIZEOF_EXPR ? "sizeof" : "__alignof__";
2753
2754   if (type_code == FUNCTION_TYPE)
2755     {
2756       if (op == SIZEOF_EXPR)
2757         {
2758           if (complain && (pedantic || warn_pointer_arith))
2759             pedwarn ("invalid application of %<sizeof%> to a function type");
2760           value = size_one_node;
2761         }
2762       else
2763         value = size_int (FUNCTION_BOUNDARY / BITS_PER_UNIT);
2764     }
2765   else if (type_code == VOID_TYPE || type_code == ERROR_MARK)
2766     {
2767       if (type_code == VOID_TYPE
2768           && complain && (pedantic || warn_pointer_arith))
2769         pedwarn ("invalid application of %qs to a void type", op_name);
2770       value = size_one_node;
2771     }
2772   else if (!COMPLETE_TYPE_P (type))
2773     {
2774       if (complain)
2775         error ("invalid application of %qs to incomplete type %qT ",
2776                op_name, type);
2777       value = size_zero_node;
2778     }
2779   else
2780     {
2781       if (op == (enum tree_code) SIZEOF_EXPR)
2782         /* Convert in case a char is more than one unit.  */
2783         value = size_binop (CEIL_DIV_EXPR, TYPE_SIZE_UNIT (type),
2784                             size_int (TYPE_PRECISION (char_type_node)
2785                                       / BITS_PER_UNIT));
2786       else
2787         value = size_int (TYPE_ALIGN_UNIT (type));
2788     }
2789
2790   /* VALUE will have an integer type with TYPE_IS_SIZETYPE set.
2791      TYPE_IS_SIZETYPE means that certain things (like overflow) will
2792      never happen.  However, this node should really have type
2793      `size_t', which is just a typedef for an ordinary integer type.  */
2794   value = fold (build1 (NOP_EXPR, size_type_node, value));
2795   gcc_assert (!TYPE_IS_SIZETYPE (TREE_TYPE (value)));
2796
2797   return value;
2798 }
2799
2800 /* Implement the __alignof keyword: Return the minimum required
2801    alignment of EXPR, measured in bytes.  For VAR_DECL's and
2802    FIELD_DECL's return DECL_ALIGN (which can be set from an
2803    "aligned" __attribute__ specification).  */
2804
2805 tree
2806 c_alignof_expr (tree expr)
2807 {
2808   tree t;
2809
2810   if (TREE_CODE (expr) == VAR_DECL)
2811     t = size_int (DECL_ALIGN_UNIT (expr));
2812
2813   else if (TREE_CODE (expr) == COMPONENT_REF
2814            && DECL_C_BIT_FIELD (TREE_OPERAND (expr, 1)))
2815     {
2816       error ("%<__alignof%> applied to a bit-field");
2817       t = size_one_node;
2818     }
2819   else if (TREE_CODE (expr) == COMPONENT_REF
2820            && TREE_CODE (TREE_OPERAND (expr, 1)) == FIELD_DECL)
2821     t = size_int (DECL_ALIGN_UNIT (TREE_OPERAND (expr, 1)));
2822
2823   else if (TREE_CODE (expr) == INDIRECT_REF)
2824     {
2825       tree t = TREE_OPERAND (expr, 0);
2826       tree best = t;
2827       int bestalign = TYPE_ALIGN (TREE_TYPE (TREE_TYPE (t)));
2828
2829       while (TREE_CODE (t) == NOP_EXPR
2830              && TREE_CODE (TREE_TYPE (TREE_OPERAND (t, 0))) == POINTER_TYPE)
2831         {
2832           int thisalign;
2833
2834           t = TREE_OPERAND (t, 0);
2835           thisalign = TYPE_ALIGN (TREE_TYPE (TREE_TYPE (t)));
2836           if (thisalign > bestalign)
2837             best = t, bestalign = thisalign;
2838         }
2839       return c_alignof (TREE_TYPE (TREE_TYPE (best)));
2840     }
2841   else
2842     return c_alignof (TREE_TYPE (expr));
2843
2844   return fold (build1 (NOP_EXPR, size_type_node, t));
2845 }
2846 \f
2847 /* Handle C and C++ default attributes.  */
2848
2849 enum built_in_attribute
2850 {
2851 #define DEF_ATTR_NULL_TREE(ENUM) ENUM,
2852 #define DEF_ATTR_INT(ENUM, VALUE) ENUM,
2853 #define DEF_ATTR_IDENT(ENUM, STRING) ENUM,
2854 #define DEF_ATTR_TREE_LIST(ENUM, PURPOSE, VALUE, CHAIN) ENUM,
2855 #include "builtin-attrs.def"
2856 #undef DEF_ATTR_NULL_TREE
2857 #undef DEF_ATTR_INT
2858 #undef DEF_ATTR_IDENT
2859 #undef DEF_ATTR_TREE_LIST
2860   ATTR_LAST
2861 };
2862
2863 static GTY(()) tree built_in_attributes[(int) ATTR_LAST];
2864
2865 static void c_init_attributes (void);
2866
2867 /* Build tree nodes and builtin functions common to both C and C++ language
2868    frontends.  */
2869
2870 void
2871 c_common_nodes_and_builtins (void)
2872 {
2873   enum builtin_type
2874   {
2875 #define DEF_PRIMITIVE_TYPE(NAME, VALUE) NAME,
2876 #define DEF_FUNCTION_TYPE_0(NAME, RETURN) NAME,
2877 #define DEF_FUNCTION_TYPE_1(NAME, RETURN, ARG1) NAME,
2878 #define DEF_FUNCTION_TYPE_2(NAME, RETURN, ARG1, ARG2) NAME,
2879 #define DEF_FUNCTION_TYPE_3(NAME, RETURN, ARG1, ARG2, ARG3) NAME,
2880 #define DEF_FUNCTION_TYPE_4(NAME, RETURN, ARG1, ARG2, ARG3, ARG4) NAME,
2881 #define DEF_FUNCTION_TYPE_VAR_0(NAME, RETURN) NAME,
2882 #define DEF_FUNCTION_TYPE_VAR_1(NAME, RETURN, ARG1) NAME,
2883 #define DEF_FUNCTION_TYPE_VAR_2(NAME, RETURN, ARG1, ARG2) NAME,
2884 #define DEF_FUNCTION_TYPE_VAR_3(NAME, RETURN, ARG1, ARG2, ARG3) NAME,
2885 #define DEF_POINTER_TYPE(NAME, TYPE) NAME,
2886 #include "builtin-types.def"
2887 #undef DEF_PRIMITIVE_TYPE
2888 #undef DEF_FUNCTION_TYPE_0
2889 #undef DEF_FUNCTION_TYPE_1
2890 #undef DEF_FUNCTION_TYPE_2
2891 #undef DEF_FUNCTION_TYPE_3
2892 #undef DEF_FUNCTION_TYPE_4
2893 #undef DEF_FUNCTION_TYPE_VAR_0
2894 #undef DEF_FUNCTION_TYPE_VAR_1
2895 #undef DEF_FUNCTION_TYPE_VAR_2
2896 #undef DEF_FUNCTION_TYPE_VAR_3
2897 #undef DEF_POINTER_TYPE
2898     BT_LAST
2899   };
2900
2901   typedef enum builtin_type builtin_type;
2902
2903   tree builtin_types[(int) BT_LAST];
2904   int wchar_type_size;
2905   tree array_domain_type;
2906   tree va_list_ref_type_node;
2907   tree va_list_arg_type_node;
2908
2909   /* Define `int' and `char' first so that dbx will output them first.  */
2910   record_builtin_type (RID_INT, NULL, integer_type_node);
2911   record_builtin_type (RID_CHAR, "char", char_type_node);
2912
2913   /* `signed' is the same as `int'.  FIXME: the declarations of "signed",
2914      "unsigned long", "long long unsigned" and "unsigned short" were in C++
2915      but not C.  Are the conditionals here needed?  */
2916   if (c_dialect_cxx ())
2917     record_builtin_type (RID_SIGNED, NULL, integer_type_node);
2918   record_builtin_type (RID_LONG, "long int", long_integer_type_node);
2919   record_builtin_type (RID_UNSIGNED, "unsigned int", unsigned_type_node);
2920   record_builtin_type (RID_MAX, "long unsigned int",
2921                        long_unsigned_type_node);
2922   if (c_dialect_cxx ())
2923     record_builtin_type (RID_MAX, "unsigned long", long_unsigned_type_node);
2924   record_builtin_type (RID_MAX, "long long int",
2925                        long_long_integer_type_node);
2926   record_builtin_type (RID_MAX, "long long unsigned int",
2927                        long_long_unsigned_type_node);
2928   if (c_dialect_cxx ())
2929     record_builtin_type (RID_MAX, "long long unsigned",
2930                          long_long_unsigned_type_node);
2931   record_builtin_type (RID_SHORT, "short int", short_integer_type_node);
2932   record_builtin_type (RID_MAX, "short unsigned int",
2933                        short_unsigned_type_node);
2934   if (c_dialect_cxx ())
2935     record_builtin_type (RID_MAX, "unsigned short",
2936                          short_unsigned_type_node);
2937
2938   /* Define both `signed char' and `unsigned char'.  */
2939   record_builtin_type (RID_MAX, "signed char", signed_char_type_node);
2940   record_builtin_type (RID_MAX, "unsigned char", unsigned_char_type_node);
2941
2942   /* These are types that c_common_type_for_size and
2943      c_common_type_for_mode use.  */
2944   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
2945                                          intQI_type_node));
2946   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
2947                                          intHI_type_node));
2948   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
2949                                          intSI_type_node));
2950   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
2951                                          intDI_type_node));
2952 #if HOST_BITS_PER_WIDE_INT >= 64
2953   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL,
2954                                          get_identifier ("__int128_t"),
2955                                          intTI_type_node));
2956 #endif
2957   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
2958                                          unsigned_intQI_type_node));
2959   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
2960                                          unsigned_intHI_type_node));
2961   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
2962                                          unsigned_intSI_type_node));
2963   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
2964                                          unsigned_intDI_type_node));
2965 #if HOST_BITS_PER_WIDE_INT >= 64
2966   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL,
2967                                          get_identifier ("__uint128_t"),
2968                                          unsigned_intTI_type_node));
2969 #endif
2970
2971   /* Create the widest literal types.  */
2972   widest_integer_literal_type_node
2973     = make_signed_type (HOST_BITS_PER_WIDE_INT * 2);
2974   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
2975                                          widest_integer_literal_type_node));
2976
2977   widest_unsigned_literal_type_node
2978     = make_unsigned_type (HOST_BITS_PER_WIDE_INT * 2);
2979   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
2980                                          widest_unsigned_literal_type_node));
2981
2982   /* `unsigned long' is the standard type for sizeof.
2983      Note that stddef.h uses `unsigned long',
2984      and this must agree, even if long and int are the same size.  */
2985   size_type_node =
2986     TREE_TYPE (identifier_global_value (get_identifier (SIZE_TYPE)));
2987   signed_size_type_node = c_common_signed_type (size_type_node);
2988   set_sizetype (size_type_node);
2989
2990   pid_type_node =
2991     TREE_TYPE (identifier_global_value (get_identifier (PID_TYPE)));
2992
2993   build_common_tree_nodes_2 (flag_short_double);
2994
2995   record_builtin_type (RID_FLOAT, NULL, float_type_node);
2996   record_builtin_type (RID_DOUBLE, NULL, double_type_node);
2997   record_builtin_type (RID_MAX, "long double", long_double_type_node);
2998
2999   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL,
3000                                          get_identifier ("complex int"),
3001                                          complex_integer_type_node));
3002   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL,
3003                                          get_identifier ("complex float"),
3004                                          complex_float_type_node));
3005   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL,
3006                                          get_identifier ("complex double"),
3007                                          complex_double_type_node));
3008   lang_hooks.decls.pushdecl
3009     (build_decl (TYPE_DECL, get_identifier ("complex long double"),
3010                  complex_long_double_type_node));
3011
3012   if (c_dialect_cxx ())
3013     /* For C++, make fileptr_type_node a distinct void * type until
3014        FILE type is defined.  */
3015     fileptr_type_node = build_variant_type_copy (ptr_type_node);
3016
3017   record_builtin_type (RID_VOID, NULL, void_type_node);
3018
3019   /* This node must not be shared.  */
3020   void_zero_node = make_node (INTEGER_CST);
3021   TREE_TYPE (void_zero_node) = void_type_node;
3022
3023   void_list_node = build_void_list_node ();
3024
3025   /* Make a type to be the domain of a few array types
3026      whose domains don't really matter.
3027      200 is small enough that it always fits in size_t
3028      and large enough that it can hold most function names for the
3029      initializations of __FUNCTION__ and __PRETTY_FUNCTION__.  */
3030   array_domain_type = build_index_type (size_int (200));
3031
3032   /* Make a type for arrays of characters.
3033      With luck nothing will ever really depend on the length of this
3034      array type.  */
3035   char_array_type_node
3036     = build_array_type (char_type_node, array_domain_type);
3037
3038   /* Likewise for arrays of ints.  */
3039   int_array_type_node
3040     = build_array_type (integer_type_node, array_domain_type);
3041
3042   string_type_node = build_pointer_type (char_type_node);
3043   const_string_type_node
3044     = build_pointer_type (build_qualified_type
3045                           (char_type_node, TYPE_QUAL_CONST));
3046
3047   /* This is special for C++ so functions can be overloaded.  */
3048   wchar_type_node = get_identifier (MODIFIED_WCHAR_TYPE);
3049   wchar_type_node = TREE_TYPE (identifier_global_value (wchar_type_node));
3050   wchar_type_size = TYPE_PRECISION (wchar_type_node);
3051   if (c_dialect_cxx ())
3052     {
3053       if (TYPE_UNSIGNED (wchar_type_node))
3054         wchar_type_node = make_unsigned_type (wchar_type_size);
3055       else
3056         wchar_type_node = make_signed_type (wchar_type_size);
3057       record_builtin_type (RID_WCHAR, "wchar_t", wchar_type_node);
3058     }
3059   else
3060     {
3061       signed_wchar_type_node = c_common_signed_type (wchar_type_node);
3062       unsigned_wchar_type_node = c_common_unsigned_type (wchar_type_node);
3063     }
3064
3065   /* This is for wide string constants.  */
3066   wchar_array_type_node
3067     = build_array_type (wchar_type_node, array_domain_type);
3068
3069   wint_type_node =
3070     TREE_TYPE (identifier_global_value (get_identifier (WINT_TYPE)));
3071
3072   intmax_type_node =
3073     TREE_TYPE (identifier_global_value (get_identifier (INTMAX_TYPE)));
3074   uintmax_type_node =
3075     TREE_TYPE (identifier_global_value (get_identifier (UINTMAX_TYPE)));
3076
3077   default_function_type = build_function_type (integer_type_node, NULL_TREE);
3078   ptrdiff_type_node
3079     = TREE_TYPE (identifier_global_value (get_identifier (PTRDIFF_TYPE)));
3080   unsigned_ptrdiff_type_node = c_common_unsigned_type (ptrdiff_type_node);
3081
3082   lang_hooks.decls.pushdecl
3083     (build_decl (TYPE_DECL, get_identifier ("__builtin_va_list"),
3084                  va_list_type_node));
3085
3086   if (TREE_CODE (va_list_type_node) == ARRAY_TYPE)
3087     {
3088       va_list_arg_type_node = va_list_ref_type_node =
3089         build_pointer_type (TREE_TYPE (va_list_type_node));
3090     }
3091   else
3092     {
3093       va_list_arg_type_node = va_list_type_node;
3094       va_list_ref_type_node = build_reference_type (va_list_type_node);
3095     }
3096
3097 #define DEF_PRIMITIVE_TYPE(ENUM, VALUE) \
3098   builtin_types[(int) ENUM] = VALUE;
3099 #define DEF_FUNCTION_TYPE_0(ENUM, RETURN)               \
3100   builtin_types[(int) ENUM]                             \
3101     = build_function_type (builtin_types[(int) RETURN], \
3102                            void_list_node);
3103 #define DEF_FUNCTION_TYPE_1(ENUM, RETURN, ARG1)                         \
3104   builtin_types[(int) ENUM]                                             \
3105     = build_function_type (builtin_types[(int) RETURN],                 \
3106                            tree_cons (NULL_TREE,                        \
3107                                       builtin_types[(int) ARG1],        \
3108                                       void_list_node));
3109 #define DEF_FUNCTION_TYPE_2(ENUM, RETURN, ARG1, ARG2)   \
3110   builtin_types[(int) ENUM]                             \
3111     = build_function_type                               \
3112       (builtin_types[(int) RETURN],                     \
3113        tree_cons (NULL_TREE,                            \
3114                   builtin_types[(int) ARG1],            \
3115                   tree_cons (NULL_TREE,                 \
3116                              builtin_types[(int) ARG2], \
3117                              void_list_node)));
3118 #define DEF_FUNCTION_TYPE_3(ENUM, RETURN, ARG1, ARG2, ARG3)              \
3119   builtin_types[(int) ENUM]                                              \
3120     = build_function_type                                                \
3121       (builtin_types[(int) RETURN],                                      \
3122        tree_cons (NULL_TREE,                                             \
3123                   builtin_types[(int) ARG1],                             \
3124                   tree_cons (NULL_TREE,                                  \
3125                              builtin_types[(int) ARG2],                  \
3126                              tree_cons (NULL_TREE,                       \
3127                                         builtin_types[(int) ARG3],       \
3128                                         void_list_node))));
3129 #define DEF_FUNCTION_TYPE_4(ENUM, RETURN, ARG1, ARG2, ARG3, ARG4)       \
3130   builtin_types[(int) ENUM]                                             \
3131     = build_function_type                                               \
3132       (builtin_types[(int) RETURN],                                     \
3133        tree_cons (NULL_TREE,                                            \
3134                   builtin_types[(int) ARG1],                            \
3135                   tree_cons (NULL_TREE,                                 \
3136                              builtin_types[(int) ARG2],                 \
3137                              tree_cons                                  \
3138                              (NULL_TREE,                                \
3139                               builtin_types[(int) ARG3],                \
3140                               tree_cons (NULL_TREE,                     \
3141                                          builtin_types[(int) ARG4],     \
3142                                          void_list_node)))));
3143 #define DEF_FUNCTION_TYPE_VAR_0(ENUM, RETURN)                           \
3144   builtin_types[(int) ENUM]                                             \
3145     = build_function_type (builtin_types[(int) RETURN], NULL_TREE);
3146 #define DEF_FUNCTION_TYPE_VAR_1(ENUM, RETURN, ARG1)                      \
3147    builtin_types[(int) ENUM]                                             \
3148     = build_function_type (builtin_types[(int) RETURN],          \
3149                            tree_cons (NULL_TREE,                         \
3150                                       builtin_types[(int) ARG1],         \
3151                                       NULL_TREE));
3152
3153 #define DEF_FUNCTION_TYPE_VAR_2(ENUM, RETURN, ARG1, ARG2)       \
3154    builtin_types[(int) ENUM]                                    \
3155     = build_function_type                                       \
3156       (builtin_types[(int) RETURN],                             \
3157        tree_cons (NULL_TREE,                                    \
3158                   builtin_types[(int) ARG1],                    \
3159                   tree_cons (NULL_TREE,                         \
3160                              builtin_types[(int) ARG2],         \
3161                              NULL_TREE)));
3162
3163 #define DEF_FUNCTION_TYPE_VAR_3(ENUM, RETURN, ARG1, ARG2, ARG3)         \
3164    builtin_types[(int) ENUM]                                            \
3165     = build_function_type                                               \
3166       (builtin_types[(int) RETURN],                                     \
3167        tree_cons (NULL_TREE,                                            \
3168                   builtin_types[(int) ARG1],                            \
3169                   tree_cons (NULL_TREE,                                 \
3170                              builtin_types[(int) ARG2],                 \
3171                              tree_cons (NULL_TREE,                      \
3172                                         builtin_types[(int) ARG3],      \
3173                                         NULL_TREE))));
3174
3175 #define DEF_POINTER_TYPE(ENUM, TYPE)                    \
3176   builtin_types[(int) ENUM]                             \
3177     = build_pointer_type (builtin_types[(int) TYPE]);
3178 #include "builtin-types.def"
3179 #undef DEF_PRIMITIVE_TYPE
3180 #undef DEF_FUNCTION_TYPE_1
3181 #undef DEF_FUNCTION_TYPE_2
3182 #undef DEF_FUNCTION_TYPE_3
3183 #undef DEF_FUNCTION_TYPE_4
3184 #undef DEF_FUNCTION_TYPE_VAR_0
3185 #undef DEF_FUNCTION_TYPE_VAR_1
3186 #undef DEF_FUNCTION_TYPE_VAR_2
3187 #undef DEF_FUNCTION_TYPE_VAR_3
3188 #undef DEF_POINTER_TYPE
3189
3190   c_init_attributes ();
3191
3192 #define DEF_BUILTIN(ENUM, NAME, CLASS, TYPE, LIBTYPE,                   \
3193                     BOTH_P, FALLBACK_P, NONANSI_P, ATTRS, IMPLICIT)     \
3194   if (NAME)                                                             \
3195     {                                                                   \
3196       tree decl;                                                        \
3197                                                                         \
3198       gcc_assert (!strncmp (NAME, "__builtin_",                         \
3199                             strlen ("__builtin_")));                    \
3200                                                                         \
3201       if (!BOTH_P)                                                      \
3202         decl = lang_hooks.builtin_function (NAME, builtin_types[TYPE],  \
3203                                  ENUM,                                  \
3204                                  CLASS,                                 \
3205                                  (FALLBACK_P                            \
3206                                   ? (NAME + strlen ("__builtin_"))      \
3207                                   : NULL),                              \
3208                                  built_in_attributes[(int) ATTRS]);     \
3209       else                                                              \
3210         decl = builtin_function_2 (NAME,                                \
3211                                    NAME + strlen ("__builtin_"),        \
3212                                    builtin_types[TYPE],                 \
3213                                    builtin_types[LIBTYPE],              \
3214                                    ENUM,                                \
3215                                    CLASS,                               \
3216                                    FALLBACK_P,                          \
3217                                    NONANSI_P,                           \
3218                                    built_in_attributes[(int) ATTRS]);   \
3219                                                                         \
3220       built_in_decls[(int) ENUM] = decl;                                \
3221       if (IMPLICIT)                                                     \
3222         implicit_built_in_decls[(int) ENUM] = decl;                     \
3223     }
3224 #include "builtins.def"
3225 #undef DEF_BUILTIN
3226
3227   targetm.init_builtins ();
3228   if (flag_mudflap)
3229     mudflap_init ();
3230
3231   main_identifier_node = get_identifier ("main");
3232 }
3233
3234 tree
3235 build_va_arg (tree expr, tree type)
3236 {
3237   return build1 (VA_ARG_EXPR, type, expr);
3238 }
3239
3240
3241 /* Linked list of disabled built-in functions.  */
3242
3243 typedef struct disabled_builtin
3244 {
3245   const char *name;
3246   struct disabled_builtin *next;
3247 } disabled_builtin;
3248 static disabled_builtin *disabled_builtins = NULL;
3249
3250 static bool builtin_function_disabled_p (const char *);
3251
3252 /* Disable a built-in function specified by -fno-builtin-NAME.  If NAME
3253    begins with "__builtin_", give an error.  */
3254
3255 void
3256 disable_builtin_function (const char *name)
3257 {
3258   if (strncmp (name, "__builtin_", strlen ("__builtin_")) == 0)
3259     error ("cannot disable built-in function %qs", name);
3260   else
3261     {
3262       disabled_builtin *new_disabled_builtin = XNEW (disabled_builtin);
3263       new_disabled_builtin->name = name;
3264       new_disabled_builtin->next = disabled_builtins;
3265       disabled_builtins = new_disabled_builtin;
3266     }
3267 }
3268
3269
3270 /* Return true if the built-in function NAME has been disabled, false
3271    otherwise.  */
3272
3273 static bool
3274 builtin_function_disabled_p (const char *name)
3275 {
3276   disabled_builtin *p;
3277   for (p = disabled_builtins; p != NULL; p = p->next)
3278     {
3279       if (strcmp (name, p->name) == 0)
3280         return true;
3281     }
3282   return false;
3283 }
3284
3285
3286 /* Possibly define a builtin function with one or two names.  BUILTIN_NAME
3287    is an __builtin_-prefixed name; NAME is the ordinary name; one or both
3288    of these may be NULL (though both being NULL is useless).
3289    BUILTIN_TYPE is the type of the __builtin_-prefixed function;
3290    TYPE is the type of the function with the ordinary name.  These
3291    may differ if the ordinary name is declared with a looser type to avoid
3292    conflicts with headers.  FUNCTION_CODE and CL are as for
3293    builtin_function.  If LIBRARY_NAME_P is nonzero, NAME is passed as
3294    the LIBRARY_NAME parameter to builtin_function when declaring BUILTIN_NAME.
3295    If NONANSI_P is true, the name NAME is treated as a non-ANSI name;
3296    ATTRS is the tree list representing the builtin's function attributes.
3297    Returns the declaration of BUILTIN_NAME, if any, otherwise
3298    the declaration of NAME.  Does not declare NAME if flag_no_builtin,
3299    or if NONANSI_P and flag_no_nonansi_builtin.  */
3300
3301 static tree
3302 builtin_function_2 (const char *builtin_name, const char *name,
3303                     tree builtin_type, tree type,
3304                     enum built_in_function function_code,
3305                     enum built_in_class cl, int library_name_p,
3306                     bool nonansi_p, tree attrs)
3307 {
3308   tree bdecl = NULL_TREE;
3309   tree decl = NULL_TREE;
3310
3311   if (builtin_name != 0)
3312     bdecl = lang_hooks.builtin_function (builtin_name, builtin_type,
3313                                          function_code, cl,
3314                                          library_name_p ? name : NULL, attrs);
3315
3316   if (name != 0 && !flag_no_builtin && !builtin_function_disabled_p (name)
3317       && !(nonansi_p && flag_no_nonansi_builtin))
3318     decl = lang_hooks.builtin_function (name, type, function_code, cl,
3319                                         NULL, attrs);
3320
3321   return (bdecl != 0 ? bdecl : decl);
3322 }
3323 \f
3324 /* Nonzero if the type T promotes to int.  This is (nearly) the
3325    integral promotions defined in ISO C99 6.3.1.1/2.  */
3326
3327 bool
3328 c_promoting_integer_type_p (tree t)
3329 {
3330   switch (TREE_CODE (t))
3331     {
3332     case INTEGER_TYPE:
3333       return (TYPE_MAIN_VARIANT (t) == char_type_node
3334               || TYPE_MAIN_VARIANT (t) == signed_char_type_node
3335               || TYPE_MAIN_VARIANT (t) == unsigned_char_type_node
3336               || TYPE_MAIN_VARIANT (t) == short_integer_type_node
3337               || TYPE_MAIN_VARIANT (t) == short_unsigned_type_node
3338               || TYPE_PRECISION (t) < TYPE_PRECISION (integer_type_node));
3339
3340     case ENUMERAL_TYPE:
3341       /* ??? Technically all enumerations not larger than an int
3342          promote to an int.  But this is used along code paths
3343          that only want to notice a size change.  */
3344       return TYPE_PRECISION (t) < TYPE_PRECISION (integer_type_node);
3345
3346     case BOOLEAN_TYPE:
3347       return 1;
3348
3349     default:
3350       return 0;
3351     }
3352 }
3353
3354 /* Return 1 if PARMS specifies a fixed number of parameters
3355    and none of their types is affected by default promotions.  */
3356
3357 int
3358 self_promoting_args_p (tree parms)
3359 {
3360   tree t;
3361   for (t = parms; t; t = TREE_CHAIN (t))
3362     {
3363       tree type = TREE_VALUE (t);
3364
3365       if (TREE_CHAIN (t) == 0 && type != void_type_node)
3366         return 0;
3367
3368       if (type == 0)
3369         return 0;
3370
3371       if (TYPE_MAIN_VARIANT (type) == float_type_node)
3372         return 0;
3373
3374       if (c_promoting_integer_type_p (type))
3375         return 0;
3376     }
3377   return 1;
3378 }
3379
3380 /* Recursively examines the array elements of TYPE, until a non-array
3381    element type is found.  */
3382
3383 tree
3384 strip_array_types (tree type)
3385 {
3386   while (TREE_CODE (type) == ARRAY_TYPE)
3387     type = TREE_TYPE (type);
3388
3389   return type;
3390 }
3391
3392 /* Recursively remove any '*' or '&' operator from TYPE.  */
3393 tree
3394 strip_pointer_operator (tree t)
3395 {
3396   while (POINTER_TYPE_P (t))
3397     t = TREE_TYPE (t);
3398   return t;
3399 }
3400
3401 /* Walk the statement tree, rooted at *tp.  Apply FUNC to all the
3402    sub-trees of *TP in a pre-order traversal.  FUNC is called with the
3403    DATA and the address of each sub-tree.  If FUNC returns a non-NULL
3404    value, the traversal is aborted, and the value returned by FUNC is
3405    returned.  If FUNC sets WALK_SUBTREES to zero, then the subtrees of
3406    the node being visited are not walked.
3407
3408    We don't need a without_duplicates variant of this one because the
3409    statement tree is a tree, not a graph.  */
3410
3411 tree
3412 walk_stmt_tree (tree *tp, walk_tree_fn func, void *data)
3413 {
3414   enum tree_code code;
3415   int walk_subtrees;
3416   tree result;
3417   int i, len;
3418
3419 #define WALK_SUBTREE(NODE)                              \
3420   do                                                    \
3421     {                                                   \
3422       result = walk_stmt_tree (&(NODE), func, data);    \
3423       if (result)                                       \
3424         return result;                                  \
3425     }                                                   \
3426   while (0)
3427
3428   /* Skip empty subtrees.  */
3429   if (!*tp)
3430     return NULL_TREE;
3431
3432   /* Skip subtrees below non-statement nodes.  */
3433   if (!STATEMENT_CODE_P (TREE_CODE (*tp)))
3434     return NULL_TREE;
3435
3436   /* Call the function.  */
3437   walk_subtrees = 1;
3438   result = (*func) (tp, &walk_subtrees, data);
3439
3440   /* If we found something, return it.  */
3441   if (result)
3442     return result;
3443
3444   /* FUNC may have modified the tree, recheck that we're looking at a
3445      statement node.  */
3446   code = TREE_CODE (*tp);
3447   if (!STATEMENT_CODE_P (code))
3448     return NULL_TREE;
3449
3450   /* Visit the subtrees unless FUNC decided that there was nothing
3451      interesting below this point in the tree.  */
3452   if (walk_subtrees)
3453     {
3454       /* Walk over all the sub-trees of this operand.  Statement nodes
3455          never contain RTL, and we needn't worry about TARGET_EXPRs.  */
3456       len = TREE_CODE_LENGTH (code);
3457
3458       /* Go through the subtrees.  We need to do this in forward order so
3459          that the scope of a FOR_EXPR is handled properly.  */
3460       for (i = 0; i < len; ++i)
3461         WALK_SUBTREE (TREE_OPERAND (*tp, i));
3462     }
3463
3464   /* Finally visit the chain.  This can be tail-recursion optimized if
3465      we write it this way.  */
3466   return walk_stmt_tree (&TREE_CHAIN (*tp), func, data);
3467
3468 #undef WALK_SUBTREE
3469 }
3470
3471 /* Used to compare case labels.  K1 and K2 are actually tree nodes
3472    representing case labels, or NULL_TREE for a `default' label.
3473    Returns -1 if K1 is ordered before K2, -1 if K1 is ordered after
3474    K2, and 0 if K1 and K2 are equal.  */
3475
3476 int
3477 case_compare (splay_tree_key k1, splay_tree_key k2)
3478 {
3479   /* Consider a NULL key (such as arises with a `default' label) to be
3480      smaller than anything else.  */
3481   if (!k1)
3482     return k2 ? -1 : 0;
3483   else if (!k2)
3484     return k1 ? 1 : 0;
3485
3486   return tree_int_cst_compare ((tree) k1, (tree) k2);
3487 }
3488
3489 /* Process a case label for the range LOW_VALUE ... HIGH_VALUE.  If
3490    LOW_VALUE and HIGH_VALUE are both NULL_TREE then this case label is
3491    actually a `default' label.  If only HIGH_VALUE is NULL_TREE, then
3492    case label was declared using the usual C/C++ syntax, rather than
3493    the GNU case range extension.  CASES is a tree containing all the
3494    case ranges processed so far; COND is the condition for the
3495    switch-statement itself.  Returns the CASE_LABEL_EXPR created, or
3496    ERROR_MARK_NODE if no CASE_LABEL_EXPR is created.  */
3497
3498 tree
3499 c_add_case_label (splay_tree cases, tree cond, tree orig_type,
3500                   tree low_value, tree high_value)
3501 {
3502   tree type;
3503   tree label;
3504   tree case_label;
3505   splay_tree_node node;
3506
3507   /* Create the LABEL_DECL itself.  */
3508   label = create_artificial_label ();
3509
3510   /* If there was an error processing the switch condition, bail now
3511      before we get more confused.  */
3512   if (!cond || cond == error_mark_node)
3513     goto error_out;
3514
3515   if ((low_value && TREE_TYPE (low_value)
3516        && POINTER_TYPE_P (TREE_TYPE (low_value)))
3517       || (high_value && TREE_TYPE (high_value)
3518           && POINTER_TYPE_P (TREE_TYPE (high_value))))
3519     error ("pointers are not permitted as case values");
3520
3521   /* Case ranges are a GNU extension.  */
3522   if (high_value && pedantic)
3523     pedwarn ("range expressions in switch statements are non-standard");
3524
3525   type = TREE_TYPE (cond);
3526   if (low_value)
3527     {
3528       low_value = check_case_value (low_value);
3529       low_value = convert_and_check (type, low_value);
3530     }
3531   if (high_value)
3532     {
3533       high_value = check_case_value (high_value);
3534       high_value = convert_and_check (type, high_value);
3535     }
3536
3537   /* If an error has occurred, bail out now.  */
3538   if (low_value == error_mark_node || high_value == error_mark_node)
3539     goto error_out;
3540
3541   /* If the LOW_VALUE and HIGH_VALUE are the same, then this isn't
3542      really a case range, even though it was written that way.  Remove
3543      the HIGH_VALUE to simplify later processing.  */
3544   if (tree_int_cst_equal (low_value, high_value))
3545     high_value = NULL_TREE;
3546   if (low_value && high_value
3547       && !tree_int_cst_lt (low_value, high_value))
3548     warning ("empty range specified");
3549
3550   /* See if the case is in range of the type of the original testing
3551      expression.  If both low_value and high_value are out of range,
3552      don't insert the case label and return NULL_TREE.  */
3553   if (low_value
3554       && !check_case_bounds (type, orig_type,
3555                              &low_value, high_value ? &high_value : NULL))
3556     return NULL_TREE;
3557
3558   /* Look up the LOW_VALUE in the table of case labels we already
3559      have.  */
3560   node = splay_tree_lookup (cases, (splay_tree_key) low_value);
3561   /* If there was not an exact match, check for overlapping ranges.
3562      There's no need to do this if there's no LOW_VALUE or HIGH_VALUE;
3563      that's a `default' label and the only overlap is an exact match.  */
3564   if (!node && (low_value || high_value))
3565     {
3566       splay_tree_node low_bound;
3567       splay_tree_node high_bound;
3568
3569       /* Even though there wasn't an exact match, there might be an
3570          overlap between this case range and another case range.
3571          Since we've (inductively) not allowed any overlapping case
3572          ranges, we simply need to find the greatest low case label
3573          that is smaller that LOW_VALUE, and the smallest low case
3574          label that is greater than LOW_VALUE.  If there is an overlap
3575          it will occur in one of these two ranges.  */
3576       low_bound = splay_tree_predecessor (cases,
3577                                           (splay_tree_key) low_value);
3578       high_bound = splay_tree_successor (cases,
3579                                          (splay_tree_key) low_value);
3580
3581       /* Check to see if the LOW_BOUND overlaps.  It is smaller than
3582          the LOW_VALUE, so there is no need to check unless the
3583          LOW_BOUND is in fact itself a case range.  */
3584       if (low_bound
3585           && CASE_HIGH ((tree) low_bound->value)
3586           && tree_int_cst_compare (CASE_HIGH ((tree) low_bound->value),
3587                                     low_value) >= 0)
3588         node = low_bound;
3589       /* Check to see if the HIGH_BOUND overlaps.  The low end of that
3590          range is bigger than the low end of the current range, so we
3591          are only interested if the current range is a real range, and
3592          not an ordinary case label.  */
3593       else if (high_bound
3594                && high_value
3595                && (tree_int_cst_compare ((tree) high_bound->key,
3596                                          high_value)
3597                    <= 0))
3598         node = high_bound;
3599     }
3600   /* If there was an overlap, issue an error.  */
3601   if (node)
3602     {
3603       tree duplicate = CASE_LABEL ((tree) node->value);
3604
3605       if (high_value)
3606         {
3607           error ("duplicate (or overlapping) case value");
3608           error ("%Jthis is the first entry overlapping that value", duplicate);
3609         }
3610       else if (low_value)
3611         {
3612           error ("duplicate case value") ;
3613           error ("%Jpreviously used here", duplicate);
3614         }
3615       else
3616         {
3617           error ("multiple default labels in one switch");
3618           error ("%Jthis is the first default label", duplicate);
3619         }
3620       goto error_out;
3621     }
3622
3623   /* Add a CASE_LABEL to the statement-tree.  */
3624   case_label = add_stmt (build_case_label (low_value, high_value, label));
3625   /* Register this case label in the splay tree.  */
3626   splay_tree_insert (cases,
3627                      (splay_tree_key) low_value,
3628                      (splay_tree_value) case_label);
3629
3630   return case_label;
3631
3632  error_out:
3633   /* Add a label so that the back-end doesn't think that the beginning of
3634      the switch is unreachable.  Note that we do not add a case label, as
3635      that just leads to duplicates and thence to aborts later on.  */
3636   if (!cases->root)
3637     {
3638       tree t = create_artificial_label ();
3639       add_stmt (build_stmt (LABEL_EXPR, t));
3640     }
3641   return error_mark_node;
3642 }
3643
3644 /* Subroutines of c_do_switch_warnings, called via splay_tree_foreach.
3645    Used to verify that case values match up with enumerator values.  */
3646
3647 static void
3648 match_case_to_enum_1 (tree key, tree type, tree label)
3649 {
3650   char buf[2 + 2*HOST_BITS_PER_WIDE_INT/4 + 1];
3651
3652   /* ??? Not working too hard to print the double-word value.
3653      Should perhaps be done with %lwd in the diagnostic routines?  */
3654   if (TREE_INT_CST_HIGH (key) == 0)
3655     snprintf (buf, sizeof (buf), HOST_WIDE_INT_PRINT_UNSIGNED,
3656               TREE_INT_CST_LOW (key));
3657   else if (!TYPE_UNSIGNED (type)
3658            && TREE_INT_CST_HIGH (key) == -1
3659            && TREE_INT_CST_LOW (key) != 0)
3660     snprintf (buf, sizeof (buf), "-" HOST_WIDE_INT_PRINT_UNSIGNED,
3661               -TREE_INT_CST_LOW (key));
3662   else
3663     snprintf (buf, sizeof (buf), HOST_WIDE_INT_PRINT_DOUBLE_HEX,
3664               TREE_INT_CST_HIGH (key), TREE_INT_CST_LOW (key));
3665
3666   if (TYPE_NAME (type) == 0)
3667     warning ("%Jcase value %qs not in enumerated type",
3668              CASE_LABEL (label), buf);
3669   else
3670     warning ("%Jcase value %qs not in enumerated type %qT",
3671              CASE_LABEL (label), buf, type);
3672 }
3673
3674 static int
3675 match_case_to_enum (splay_tree_node node, void *data)
3676 {
3677   tree label = (tree) node->value;
3678   tree type = (tree) data;
3679
3680   /* Skip default case.  */
3681   if (!CASE_LOW (label))
3682     return 0;
3683
3684   /* If TREE_ADDRESSABLE is not set, that means CASE_LOW did not appear
3685      when we did our enum->case scan.  Reset our scratch bit after.  */
3686   if (!TREE_ADDRESSABLE (label))
3687     match_case_to_enum_1 (CASE_LOW (label), type, label);
3688   else
3689     TREE_ADDRESSABLE (label) = 0;
3690
3691   /* If CASE_HIGH is non-null, we have a range.  Here we must search.
3692      Note that the old code in stmt.c did not check for the values in
3693      the range either, just the endpoints.  */
3694   if (CASE_HIGH (label))
3695     {
3696       tree chain, key = CASE_HIGH (label);
3697
3698       for (chain = TYPE_VALUES (type);
3699            chain && !tree_int_cst_equal (key, TREE_VALUE (chain));
3700            chain = TREE_CHAIN (chain))
3701         continue;
3702       if (!chain)
3703         match_case_to_enum_1 (key, type, label);
3704     }
3705
3706   return 0;
3707 }
3708
3709 /* Handle -Wswitch*.  Called from the front end after parsing the switch
3710    construct.  */
3711 /* ??? Should probably be somewhere generic, since other languages besides
3712    C and C++ would want this.  We'd want to agree on the datastructure,
3713    however, which is a problem.  Alternately, we operate on gimplified
3714    switch_exprs, which I don't especially like.  At the moment, however,
3715    C/C++ are the only tree-ssa languages that support enumerations at all,
3716    so the point is moot.  */
3717
3718 void
3719 c_do_switch_warnings (splay_tree cases, tree switch_stmt)
3720 {
3721   splay_tree_node default_node;
3722   location_t switch_location;
3723   tree type;
3724
3725   if (!warn_switch && !warn_switch_enum && !warn_switch_default)
3726     return;
3727
3728   if (EXPR_HAS_LOCATION (switch_stmt))
3729     switch_location = EXPR_LOCATION (switch_stmt);
3730   else
3731     switch_location = input_location;
3732
3733   type = SWITCH_TYPE (switch_stmt);
3734
3735   default_node = splay_tree_lookup (cases, (splay_tree_key) NULL);
3736   if (warn_switch_default && !default_node)
3737     warning ("%Hswitch missing default case", &switch_location);
3738
3739   /* If the switch expression was an enumerated type, check that
3740      exactly all enumeration literals are covered by the cases.
3741      The check is made when -Wswitch was specified and there is no
3742      default case, or when -Wswitch-enum was specified.  */
3743   if (((warn_switch && !default_node) || warn_switch_enum)
3744       && type && TREE_CODE (type) == ENUMERAL_TYPE
3745       && TREE_CODE (SWITCH_COND (switch_stmt)) != INTEGER_CST)
3746     {
3747       tree chain;
3748
3749       /* The time complexity here is O(N*lg(N)) worst case, but for the
3750          common case of monotonically increasing enumerators, it is
3751          O(N), since the nature of the splay tree will keep the next
3752          element adjacent to the root at all times.  */
3753
3754       for (chain = TYPE_VALUES (type); chain; chain = TREE_CHAIN (chain))
3755         {
3756           splay_tree_node node
3757             = splay_tree_lookup (cases, (splay_tree_key) TREE_VALUE (chain));
3758
3759           if (node)
3760             {
3761               /* Mark the CASE_LOW part of the case entry as seen, so
3762                  that we save time later.  Choose TREE_ADDRESSABLE
3763                  randomly as a bit that won't have been set to-date.  */
3764               tree label = (tree) node->value;
3765               TREE_ADDRESSABLE (label) = 1;
3766             }
3767           else
3768             {
3769               /* Warn if there are enumerators that don't correspond to
3770                  case expressions.  */
3771               warning ("%Henumeration value %qE not handled in switch",
3772                        &switch_location, TREE_PURPOSE (chain));
3773             }
3774         }
3775
3776       /* Warn if there are case expressions that don't correspond to
3777          enumerators.  This can occur since C and C++ don't enforce
3778          type-checking of assignments to enumeration variables.
3779
3780          The time complexity here is O(N**2) worst case, since we've
3781          not sorted the enumeration values.  However, in the absence
3782          of case ranges this is O(N), since all single cases that
3783          corresponded to enumerations have been marked above.  */
3784
3785       splay_tree_foreach (cases, match_case_to_enum, type);
3786     }
3787 }
3788
3789 /* Finish an expression taking the address of LABEL (an
3790    IDENTIFIER_NODE).  Returns an expression for the address.  */
3791
3792 tree
3793 finish_label_address_expr (tree label)
3794 {
3795   tree result;
3796
3797   if (pedantic)
3798     pedwarn ("taking the address of a label is non-standard");
3799
3800   if (label == error_mark_node)
3801     return error_mark_node;
3802
3803   label = lookup_label (label);
3804   if (label == NULL_TREE)
3805     result = null_pointer_node;
3806   else
3807     {
3808       TREE_USED (label) = 1;
3809       result = build1 (ADDR_EXPR, ptr_type_node, label);
3810       /* The current function in not necessarily uninlinable.
3811          Computed gotos are incompatible with inlining, but the value
3812          here could be used only in a diagnostic, for example.  */
3813     }
3814
3815   return result;
3816 }
3817
3818 /* Hook used by expand_expr to expand language-specific tree codes.  */
3819 /* The only things that should go here are bits needed to expand
3820    constant initializers.  Everything else should be handled by the
3821    gimplification routines.  */
3822
3823 rtx
3824 c_expand_expr (tree exp, rtx target, enum machine_mode tmode,
3825                int modifier /* Actually enum_modifier.  */,
3826                rtx *alt_rtl)
3827 {
3828   switch (TREE_CODE (exp))
3829     {
3830     case COMPOUND_LITERAL_EXPR:
3831       {
3832         /* Initialize the anonymous variable declared in the compound
3833            literal, then return the variable.  */
3834         tree decl = COMPOUND_LITERAL_EXPR_DECL (exp);
3835         emit_local_var (decl);
3836         return expand_expr_real (decl, target, tmode, modifier, alt_rtl);
3837       }
3838
3839     default:
3840       gcc_unreachable ();
3841     }
3842 }
3843
3844 /* Hook used by staticp to handle language-specific tree codes.  */
3845
3846 tree
3847 c_staticp (tree exp)
3848 {
3849   return (TREE_CODE (exp) == COMPOUND_LITERAL_EXPR
3850           && TREE_STATIC (COMPOUND_LITERAL_EXPR_DECL (exp))
3851           ? exp : NULL);
3852 }
3853 \f
3854
3855 /* Given a boolean expression ARG, return a tree representing an increment
3856    or decrement (as indicated by CODE) of ARG.  The front end must check for
3857    invalid cases (e.g., decrement in C++).  */
3858 tree
3859 boolean_increment (enum tree_code code, tree arg)
3860 {
3861   tree val;
3862   tree true_res = boolean_true_node;
3863
3864   arg = stabilize_reference (arg);
3865   switch (code)
3866     {
3867     case PREINCREMENT_EXPR:
3868       val = build2 (MODIFY_EXPR, TREE_TYPE (arg), arg, true_res);
3869       break;
3870     case POSTINCREMENT_EXPR:
3871       val = build2 (MODIFY_EXPR, TREE_TYPE (arg), arg, true_res);
3872       arg = save_expr (arg);
3873       val = build2 (COMPOUND_EXPR, TREE_TYPE (arg), val, arg);
3874       val = build2 (COMPOUND_EXPR, TREE_TYPE (arg), arg, val);
3875       break;
3876     case PREDECREMENT_EXPR:
3877       val = build2 (MODIFY_EXPR, TREE_TYPE (arg), arg,
3878                     invert_truthvalue (arg));
3879       break;
3880     case POSTDECREMENT_EXPR:
3881       val = build2 (MODIFY_EXPR, TREE_TYPE (arg), arg,
3882                     invert_truthvalue (arg));
3883       arg = save_expr (arg);
3884       val = build2 (COMPOUND_EXPR, TREE_TYPE (arg), val, arg);
3885       val = build2 (COMPOUND_EXPR, TREE_TYPE (arg), arg, val);
3886       break;
3887     default:
3888       gcc_unreachable ();
3889     }
3890   TREE_SIDE_EFFECTS (val) = 1;
3891   return val;
3892 }
3893 \f
3894 /* Built-in macros for stddef.h, that require macros defined in this
3895    file.  */
3896 void
3897 c_stddef_cpp_builtins(void)
3898 {
3899   builtin_define_with_value ("__SIZE_TYPE__", SIZE_TYPE, 0);
3900   builtin_define_with_value ("__PTRDIFF_TYPE__", PTRDIFF_TYPE, 0);
3901   builtin_define_with_value ("__WCHAR_TYPE__", MODIFIED_WCHAR_TYPE, 0);
3902   builtin_define_with_value ("__WINT_TYPE__", WINT_TYPE, 0);
3903   builtin_define_with_value ("__INTMAX_TYPE__", INTMAX_TYPE, 0);
3904   builtin_define_with_value ("__UINTMAX_TYPE__", UINTMAX_TYPE, 0);
3905 }
3906
3907 static void
3908 c_init_attributes (void)
3909 {
3910   /* Fill in the built_in_attributes array.  */
3911 #define DEF_ATTR_NULL_TREE(ENUM)                                \
3912   built_in_attributes[(int) ENUM] = NULL_TREE;
3913 #define DEF_ATTR_INT(ENUM, VALUE)                               \
3914   built_in_attributes[(int) ENUM] = build_int_cst (NULL_TREE, VALUE);
3915 #define DEF_ATTR_IDENT(ENUM, STRING)                            \
3916   built_in_attributes[(int) ENUM] = get_identifier (STRING);
3917 #define DEF_ATTR_TREE_LIST(ENUM, PURPOSE, VALUE, CHAIN) \
3918   built_in_attributes[(int) ENUM]                       \
3919     = tree_cons (built_in_attributes[(int) PURPOSE],    \
3920                  built_in_attributes[(int) VALUE],      \
3921                  built_in_attributes[(int) CHAIN]);
3922 #include "builtin-attrs.def"
3923 #undef DEF_ATTR_NULL_TREE
3924 #undef DEF_ATTR_INT
3925 #undef DEF_ATTR_IDENT
3926 #undef DEF_ATTR_TREE_LIST
3927 }
3928
3929 /* Attribute handlers common to C front ends.  */
3930
3931 /* Handle a "packed" attribute; arguments as in
3932    struct attribute_spec.handler.  */
3933
3934 static tree
3935 handle_packed_attribute (tree *node, tree name, tree ARG_UNUSED (args),
3936                          int flags, bool *no_add_attrs)
3937 {
3938   if (TYPE_P (*node))
3939     {
3940       if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
3941         *node = build_variant_type_copy (*node);
3942       TYPE_PACKED (*node) = 1;
3943       if (TYPE_MAIN_VARIANT (*node) == *node)
3944         {
3945           /* If it is the main variant, then pack the other variants
3946              too. This happens in,
3947
3948              struct Foo {
3949                struct Foo const *ptr; // creates a variant w/o packed flag
3950                } __ attribute__((packed)); // packs it now.
3951           */
3952           tree probe;
3953
3954           for (probe = *node; probe; probe = TYPE_NEXT_VARIANT (probe))
3955             TYPE_PACKED (probe) = 1;
3956         }
3957
3958     }
3959   else if (TREE_CODE (*node) == FIELD_DECL)
3960     DECL_PACKED (*node) = 1;
3961   /* We can't set DECL_PACKED for a VAR_DECL, because the bit is
3962      used for DECL_REGISTER.  It wouldn't mean anything anyway.
3963      We can't set DECL_PACKED on the type of a TYPE_DECL, because
3964      that changes what the typedef is typing.  */
3965   else
3966     {
3967       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
3968       *no_add_attrs = true;
3969     }
3970
3971   return NULL_TREE;
3972 }
3973
3974 /* Handle a "nocommon" attribute; arguments as in
3975    struct attribute_spec.handler.  */
3976
3977 static tree
3978 handle_nocommon_attribute (tree *node, tree name,
3979                            tree ARG_UNUSED (args),
3980                            int ARG_UNUSED (flags), bool *no_add_attrs)
3981 {
3982   if (TREE_CODE (*node) == VAR_DECL)
3983     DECL_COMMON (*node) = 0;
3984   else
3985     {
3986       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
3987       *no_add_attrs = true;
3988     }
3989
3990   return NULL_TREE;
3991 }
3992
3993 /* Handle a "common" attribute; arguments as in
3994    struct attribute_spec.handler.  */
3995
3996 static tree
3997 handle_common_attribute (tree *node, tree name, tree ARG_UNUSED (args),
3998                          int ARG_UNUSED (flags), bool *no_add_attrs)
3999 {
4000   if (TREE_CODE (*node) == VAR_DECL)
4001     DECL_COMMON (*node) = 1;
4002   else
4003     {
4004       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
4005       *no_add_attrs = true;
4006     }
4007
4008   return NULL_TREE;
4009 }
4010
4011 /* Handle a "noreturn" attribute; arguments as in
4012    struct attribute_spec.handler.  */
4013
4014 static tree
4015 handle_noreturn_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4016                            int ARG_UNUSED (flags), bool *no_add_attrs)
4017 {
4018   tree type = TREE_TYPE (*node);
4019
4020   /* See FIXME comment in c_common_attribute_table.  */
4021   if (TREE_CODE (*node) == FUNCTION_DECL)
4022     TREE_THIS_VOLATILE (*node) = 1;
4023   else if (TREE_CODE (type) == POINTER_TYPE
4024            && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE)
4025     TREE_TYPE (*node)
4026       = build_pointer_type
4027         (build_type_variant (TREE_TYPE (type),
4028                              TYPE_READONLY (TREE_TYPE (type)), 1));
4029   else
4030     {
4031       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
4032       *no_add_attrs = true;
4033     }
4034
4035   return NULL_TREE;
4036 }
4037
4038 /* Handle a "noinline" attribute; arguments as in
4039    struct attribute_spec.handler.  */
4040
4041 static tree
4042 handle_noinline_attribute (tree *node, tree name,
4043                            tree ARG_UNUSED (args),
4044                            int ARG_UNUSED (flags), bool *no_add_attrs)
4045 {
4046   if (TREE_CODE (*node) == FUNCTION_DECL)
4047     DECL_UNINLINABLE (*node) = 1;
4048   else
4049     {
4050       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
4051       *no_add_attrs = true;
4052     }
4053
4054   return NULL_TREE;
4055 }
4056
4057 /* Handle a "always_inline" attribute; arguments as in
4058    struct attribute_spec.handler.  */
4059
4060 static tree
4061 handle_always_inline_attribute (tree *node, tree name,
4062                                 tree ARG_UNUSED (args),
4063                                 int ARG_UNUSED (flags),
4064                                 bool *no_add_attrs)
4065 {
4066   if (TREE_CODE (*node) == FUNCTION_DECL)
4067     {
4068       /* Do nothing else, just set the attribute.  We'll get at
4069          it later with lookup_attribute.  */
4070     }
4071   else
4072     {
4073       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
4074       *no_add_attrs = true;
4075     }
4076
4077   return NULL_TREE;
4078 }
4079
4080 /* Handle a "used" attribute; arguments as in
4081    struct attribute_spec.handler.  */
4082
4083 static tree
4084 handle_used_attribute (tree *pnode, tree name, tree ARG_UNUSED (args),
4085                        int ARG_UNUSED (flags), bool *no_add_attrs)
4086 {
4087   tree node = *pnode;
4088
4089   if (TREE_CODE (node) == FUNCTION_DECL
4090       || (TREE_CODE (node) == VAR_DECL && TREE_STATIC (node)))
4091     {
4092       TREE_USED (node) = 1;
4093       DECL_PRESERVE_P (node) = 1;
4094     }
4095   else
4096     {
4097       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
4098       *no_add_attrs = true;
4099     }
4100
4101   return NULL_TREE;
4102 }
4103
4104 /* Handle a "unused" attribute; arguments as in
4105    struct attribute_spec.handler.  */
4106
4107 static tree
4108 handle_unused_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4109                          int flags, bool *no_add_attrs)
4110 {
4111   if (DECL_P (*node))
4112     {
4113       tree decl = *node;
4114
4115       if (TREE_CODE (decl) == PARM_DECL
4116           || TREE_CODE (decl) == VAR_DECL
4117           || TREE_CODE (decl) == FUNCTION_DECL
4118           || TREE_CODE (decl) == LABEL_DECL
4119           || TREE_CODE (decl) == TYPE_DECL)
4120         TREE_USED (decl) = 1;
4121       else
4122         {
4123           warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
4124           *no_add_attrs = true;
4125         }
4126     }
4127   else
4128     {
4129       if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
4130         *node = build_variant_type_copy (*node);
4131       TREE_USED (*node) = 1;
4132     }
4133
4134   return NULL_TREE;
4135 }
4136
4137 /* Handle a "const" attribute; arguments as in
4138    struct attribute_spec.handler.  */
4139
4140 static tree
4141 handle_const_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4142                         int ARG_UNUSED (flags), bool *no_add_attrs)
4143 {
4144   tree type = TREE_TYPE (*node);
4145
4146   /* See FIXME comment on noreturn in c_common_attribute_table.  */
4147   if (TREE_CODE (*node) == FUNCTION_DECL)
4148     TREE_READONLY (*node) = 1;
4149   else if (TREE_CODE (type) == POINTER_TYPE
4150            && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE)
4151     TREE_TYPE (*node)
4152       = build_pointer_type
4153         (build_type_variant (TREE_TYPE (type), 1,
4154                              TREE_THIS_VOLATILE (TREE_TYPE (type))));
4155   else
4156     {
4157       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
4158       *no_add_attrs = true;
4159     }
4160
4161   return NULL_TREE;
4162 }
4163
4164 /* Handle a "transparent_union" attribute; arguments as in
4165    struct attribute_spec.handler.  */
4166
4167 static tree
4168 handle_transparent_union_attribute (tree *node, tree name,
4169                                     tree ARG_UNUSED (args), int flags,
4170                                     bool *no_add_attrs)
4171 {
4172   tree decl = NULL_TREE;
4173   tree *type = NULL;
4174   int is_type = 0;
4175
4176   if (DECL_P (*node))
4177     {
4178       decl = *node;
4179       type = &TREE_TYPE (decl);
4180       is_type = TREE_CODE (*node) == TYPE_DECL;
4181     }
4182   else if (TYPE_P (*node))
4183     type = node, is_type = 1;
4184
4185   if (is_type
4186       && TREE_CODE (*type) == UNION_TYPE
4187       && (decl == 0
4188           || (TYPE_FIELDS (*type) != 0
4189               && TYPE_MODE (*type) == DECL_MODE (TYPE_FIELDS (*type)))))
4190     {
4191       if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
4192         *type = build_variant_type_copy (*type);
4193       TYPE_TRANSPARENT_UNION (*type) = 1;
4194     }
4195   else if (decl != 0 && TREE_CODE (decl) == PARM_DECL
4196            && TREE_CODE (*type) == UNION_TYPE
4197            && TYPE_MODE (*type) == DECL_MODE (TYPE_FIELDS (*type)))
4198     DECL_TRANSPARENT_UNION (decl) = 1;
4199   else
4200     {
4201       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
4202       *no_add_attrs = true;
4203     }
4204
4205   return NULL_TREE;
4206 }
4207
4208 /* Handle a "constructor" attribute; arguments as in
4209    struct attribute_spec.handler.  */
4210
4211 static tree
4212 handle_constructor_attribute (tree *node, tree name,
4213                               tree ARG_UNUSED (args),
4214                               int ARG_UNUSED (flags),
4215                               bool *no_add_attrs)
4216 {
4217   tree decl = *node;
4218   tree type = TREE_TYPE (decl);
4219
4220   if (TREE_CODE (decl) == FUNCTION_DECL
4221       && TREE_CODE (type) == FUNCTION_TYPE
4222       && decl_function_context (decl) == 0)
4223     {
4224       DECL_STATIC_CONSTRUCTOR (decl) = 1;
4225       TREE_USED (decl) = 1;
4226     }
4227   else
4228     {
4229       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
4230       *no_add_attrs = true;
4231     }
4232
4233   return NULL_TREE;
4234 }
4235
4236 /* Handle a "destructor" attribute; arguments as in
4237    struct attribute_spec.handler.  */
4238
4239 static tree
4240 handle_destructor_attribute (tree *node, tree name,
4241                              tree ARG_UNUSED (args),
4242                              int ARG_UNUSED (flags),
4243                              bool *no_add_attrs)
4244 {
4245   tree decl = *node;
4246   tree type = TREE_TYPE (decl);
4247
4248   if (TREE_CODE (decl) == FUNCTION_DECL
4249       && TREE_CODE (type) == FUNCTION_TYPE
4250       && decl_function_context (decl) == 0)
4251     {
4252       DECL_STATIC_DESTRUCTOR (decl) = 1;
4253       TREE_USED (decl) = 1;
4254     }
4255   else
4256     {
4257       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
4258       *no_add_attrs = true;
4259     }
4260
4261   return NULL_TREE;
4262 }
4263
4264 /* Handle a "mode" attribute; arguments as in
4265    struct attribute_spec.handler.  */
4266
4267 static tree
4268 handle_mode_attribute (tree *node, tree name, tree args,
4269                        int ARG_UNUSED (flags), bool *no_add_attrs)
4270 {
4271   tree type = *node;
4272
4273   *no_add_attrs = true;
4274
4275   if (TREE_CODE (TREE_VALUE (args)) != IDENTIFIER_NODE)
4276     warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
4277   else
4278     {
4279       int j;
4280       const char *p = IDENTIFIER_POINTER (TREE_VALUE (args));
4281       int len = strlen (p);
4282       enum machine_mode mode = VOIDmode;
4283       tree typefm;
4284       bool valid_mode;
4285
4286       if (len > 4 && p[0] == '_' && p[1] == '_'
4287           && p[len - 1] == '_' && p[len - 2] == '_')
4288         {
4289           char *newp = (char *) alloca (len - 1);
4290
4291           strcpy (newp, &p[2]);
4292           newp[len - 4] = '\0';
4293           p = newp;
4294         }
4295
4296       /* Change this type to have a type with the specified mode.
4297          First check for the special modes.  */
4298       if (!strcmp (p, "byte"))
4299         mode = byte_mode;
4300       else if (!strcmp (p, "word"))
4301         mode = word_mode;
4302       else if (!strcmp (p, "pointer"))
4303         mode = ptr_mode;
4304       else
4305         for (j = 0; j < NUM_MACHINE_MODES; j++)
4306           if (!strcmp (p, GET_MODE_NAME (j)))
4307             {
4308               mode = (enum machine_mode) j;
4309               break;
4310             }
4311
4312       if (mode == VOIDmode)
4313         {
4314           error ("unknown machine mode %<%s%>", p);
4315           return NULL_TREE;
4316         }
4317
4318       valid_mode = false;
4319       switch (GET_MODE_CLASS (mode))
4320         {
4321         case MODE_INT:
4322         case MODE_PARTIAL_INT:
4323         case MODE_FLOAT:
4324           valid_mode = targetm.scalar_mode_supported_p (mode);
4325           break;
4326
4327         case MODE_COMPLEX_INT:
4328         case MODE_COMPLEX_FLOAT:
4329           valid_mode = targetm.scalar_mode_supported_p (GET_MODE_INNER (mode));
4330           break;
4331
4332         case MODE_VECTOR_INT:
4333         case MODE_VECTOR_FLOAT:
4334           warning ("specifying vector types with __attribute__ ((mode)) "
4335                    "is deprecated");
4336           warning ("use __attribute__ ((vector_size)) instead");
4337           valid_mode = vector_mode_valid_p (mode);
4338           break;
4339
4340         default:
4341           break;
4342         }
4343       if (!valid_mode)
4344         {
4345           error ("unable to emulate %<%s%>", p);
4346           return NULL_TREE;
4347         }
4348
4349       if (POINTER_TYPE_P (type))
4350         {
4351           tree (*fn)(tree, enum machine_mode, bool);
4352
4353           if (!targetm.valid_pointer_mode (mode))
4354             {
4355               error ("invalid pointer mode %<%s%>", p);
4356               return NULL_TREE;
4357             }
4358
4359           if (TREE_CODE (type) == POINTER_TYPE)
4360             fn = build_pointer_type_for_mode;
4361           else
4362             fn = build_reference_type_for_mode;
4363           typefm = fn (TREE_TYPE (type), mode, false);
4364         }
4365       else
4366         typefm = lang_hooks.types.type_for_mode (mode, TYPE_UNSIGNED (type));
4367
4368       if (typefm == NULL_TREE)
4369         {
4370           error ("no data type for mode %qs", p);
4371           return NULL_TREE;
4372         }
4373       else if (TREE_CODE (type) == ENUMERAL_TYPE)
4374         {
4375           /* For enumeral types, copy the precision from the integer
4376              type returned above.  If not an INTEGER_TYPE, we can't use
4377              this mode for this type.  */
4378           if (TREE_CODE (typefm) != INTEGER_TYPE)
4379             {
4380               error ("cannot use mode %qs for enumeral types", p);
4381               return NULL_TREE;
4382             }
4383
4384           if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
4385             type = build_variant_type_copy (type);
4386           TYPE_PRECISION (type) = TYPE_PRECISION (typefm);
4387           typefm = type;
4388         }
4389       else if (VECTOR_MODE_P (mode)
4390                ? TREE_CODE (type) != TREE_CODE (TREE_TYPE (typefm))
4391                : TREE_CODE (type) != TREE_CODE (typefm))
4392         {
4393           error ("mode %qs applied to inappropriate type", p);
4394           return NULL_TREE;
4395         }
4396
4397       *node = typefm;
4398
4399       /* No need to layout the type here.  The caller should do this.  */
4400     }
4401
4402   return NULL_TREE;
4403 }
4404
4405 /* Handle a "section" attribute; arguments as in
4406    struct attribute_spec.handler.  */
4407
4408 static tree
4409 handle_section_attribute (tree *node, tree ARG_UNUSED (name), tree args,
4410                           int ARG_UNUSED (flags), bool *no_add_attrs)
4411 {
4412   tree decl = *node;
4413
4414   if (targetm.have_named_sections)
4415     {
4416       user_defined_section_attribute = true;
4417
4418       if ((TREE_CODE (decl) == FUNCTION_DECL
4419            || TREE_CODE (decl) == VAR_DECL)
4420           && TREE_CODE (TREE_VALUE (args)) == STRING_CST)
4421         {
4422           if (TREE_CODE (decl) == VAR_DECL
4423               && current_function_decl != NULL_TREE
4424               && !TREE_STATIC (decl))
4425             {
4426               error ("%Jsection attribute cannot be specified for "
4427                      "local variables", decl);
4428               *no_add_attrs = true;
4429             }
4430
4431           /* The decl may have already been given a section attribute
4432              from a previous declaration.  Ensure they match.  */
4433           else if (DECL_SECTION_NAME (decl) != NULL_TREE
4434                    && strcmp (TREE_STRING_POINTER (DECL_SECTION_NAME (decl)),
4435                               TREE_STRING_POINTER (TREE_VALUE (args))) != 0)
4436             {
4437               error ("%Jsection of %qD conflicts with previous declaration",
4438                      *node, *node);
4439               *no_add_attrs = true;
4440             }
4441           else
4442             DECL_SECTION_NAME (decl) = TREE_VALUE (args);
4443         }
4444       else
4445         {
4446           error ("%Jsection attribute not allowed for %qD", *node, *node);
4447           *no_add_attrs = true;
4448         }
4449     }
4450   else
4451     {
4452       error ("%Jsection attributes are not supported for this target", *node);
4453       *no_add_attrs = true;
4454     }
4455
4456   return NULL_TREE;
4457 }
4458
4459 /* Handle a "aligned" attribute; arguments as in
4460    struct attribute_spec.handler.  */
4461
4462 static tree
4463 handle_aligned_attribute (tree *node, tree ARG_UNUSED (name), tree args,
4464                           int flags, bool *no_add_attrs)
4465 {
4466   tree decl = NULL_TREE;
4467   tree *type = NULL;
4468   int is_type = 0;
4469   tree align_expr = (args ? TREE_VALUE (args)
4470                      : size_int (BIGGEST_ALIGNMENT / BITS_PER_UNIT));
4471   int i;
4472
4473   if (DECL_P (*node))
4474     {
4475       decl = *node;
4476       type = &TREE_TYPE (decl);
4477       is_type = TREE_CODE (*node) == TYPE_DECL;
4478     }
4479   else if (TYPE_P (*node))
4480     type = node, is_type = 1;
4481
4482   /* Strip any NOPs of any kind.  */
4483   while (TREE_CODE (align_expr) == NOP_EXPR
4484          || TREE_CODE (align_expr) == CONVERT_EXPR
4485          || TREE_CODE (align_expr) == NON_LVALUE_EXPR)
4486     align_expr = TREE_OPERAND (align_expr, 0);
4487
4488   if (TREE_CODE (align_expr) != INTEGER_CST)
4489     {
4490       error ("requested alignment is not a constant");
4491       *no_add_attrs = true;
4492     }
4493   else if ((i = tree_log2 (align_expr)) == -1)
4494     {
4495       error ("requested alignment is not a power of 2");
4496       *no_add_attrs = true;
4497     }
4498   else if (i > HOST_BITS_PER_INT - 2)
4499     {
4500       error ("requested alignment is too large");
4501       *no_add_attrs = true;
4502     }
4503   else if (is_type)
4504     {
4505       /* If we have a TYPE_DECL, then copy the type, so that we
4506          don't accidentally modify a builtin type.  See pushdecl.  */
4507       if (decl && TREE_TYPE (decl) != error_mark_node
4508           && DECL_ORIGINAL_TYPE (decl) == NULL_TREE)
4509         {
4510           tree tt = TREE_TYPE (decl);
4511           *type = build_variant_type_copy (*type);
4512           DECL_ORIGINAL_TYPE (decl) = tt;
4513           TYPE_NAME (*type) = decl;
4514           TREE_USED (*type) = TREE_USED (decl);
4515           TREE_TYPE (decl) = *type;
4516         }
4517       else if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
4518         *type = build_variant_type_copy (*type);
4519
4520       TYPE_ALIGN (*type) = (1 << i) * BITS_PER_UNIT;
4521       TYPE_USER_ALIGN (*type) = 1;
4522     }
4523   else if (TREE_CODE (decl) != VAR_DECL
4524            && TREE_CODE (decl) != FIELD_DECL)
4525     {
4526       error ("%Jalignment may not be specified for %qD", decl, decl);
4527       *no_add_attrs = true;
4528     }
4529   else
4530     {
4531       DECL_ALIGN (decl) = (1 << i) * BITS_PER_UNIT;
4532       DECL_USER_ALIGN (decl) = 1;
4533     }
4534
4535   return NULL_TREE;
4536 }
4537
4538 /* Handle a "weak" attribute; arguments as in
4539    struct attribute_spec.handler.  */
4540
4541 static tree
4542 handle_weak_attribute (tree *node, tree ARG_UNUSED (name),
4543                        tree ARG_UNUSED (args),
4544                        int ARG_UNUSED (flags),
4545                        bool * ARG_UNUSED (no_add_attrs))
4546 {
4547   declare_weak (*node);
4548
4549   return NULL_TREE;
4550 }
4551
4552 /* Handle an "alias" attribute; arguments as in
4553    struct attribute_spec.handler.  */
4554
4555 static tree
4556 handle_alias_attribute (tree *node, tree name, tree args,
4557                         int ARG_UNUSED (flags), bool *no_add_attrs)
4558 {
4559   tree decl = *node;
4560
4561   if ((TREE_CODE (decl) == FUNCTION_DECL && DECL_INITIAL (decl))
4562       || (TREE_CODE (decl) != FUNCTION_DECL && !DECL_EXTERNAL (decl)))
4563     {
4564       error ("%J%qD defined both normally and as an alias", decl, decl);
4565       *no_add_attrs = true;
4566     }
4567
4568   /* Note that the very first time we process a nested declaration,
4569      decl_function_context will not be set.  Indeed, *would* never
4570      be set except for the DECL_INITIAL/DECL_EXTERNAL frobbery that
4571      we do below.  After such frobbery, pushdecl would set the context.
4572      In any case, this is never what we want.  */
4573   else if (decl_function_context (decl) == 0 && current_function_decl == NULL)
4574     {
4575       tree id;
4576
4577       id = TREE_VALUE (args);
4578       if (TREE_CODE (id) != STRING_CST)
4579         {
4580           error ("alias arg not a string");
4581           *no_add_attrs = true;
4582           return NULL_TREE;
4583         }
4584       id = get_identifier (TREE_STRING_POINTER (id));
4585       /* This counts as a use of the object pointed to.  */
4586       TREE_USED (id) = 1;
4587
4588       if (TREE_CODE (decl) == FUNCTION_DECL)
4589         DECL_INITIAL (decl) = error_mark_node;
4590       else
4591         {
4592           DECL_EXTERNAL (decl) = 0;
4593           TREE_STATIC (decl) = 1;
4594         }
4595     }
4596   else
4597     {
4598       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
4599       *no_add_attrs = true;
4600     }
4601
4602   return NULL_TREE;
4603 }
4604
4605 /* Handle an "visibility" attribute; arguments as in
4606    struct attribute_spec.handler.  */
4607
4608 static tree
4609 handle_visibility_attribute (tree *node, tree name, tree args,
4610                              int ARG_UNUSED (flags),
4611                              bool *no_add_attrs)
4612 {
4613   tree decl = *node;
4614   tree id = TREE_VALUE (args);
4615
4616   *no_add_attrs = true;
4617
4618   if (TYPE_P (*node))
4619     {
4620       if (TREE_CODE (*node) != RECORD_TYPE && TREE_CODE (*node) != UNION_TYPE)
4621        {
4622          warning ("%qs attribute ignored on non-class types",
4623                   IDENTIFIER_POINTER (name));
4624          return NULL_TREE;
4625        }
4626     }
4627   else if (decl_function_context (decl) != 0 || !TREE_PUBLIC (decl))
4628     {
4629       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
4630       return NULL_TREE;
4631     }
4632
4633   if (TREE_CODE (id) != STRING_CST)
4634     {
4635       error ("visibility arg not a string");
4636       return NULL_TREE;
4637     }
4638
4639   /*  If this is a type, set the visibility on the type decl.  */
4640   if (TYPE_P (decl))
4641     {
4642       decl = TYPE_NAME (decl);
4643       if (!decl)
4644         return NULL_TREE;
4645     }
4646
4647   if (strcmp (TREE_STRING_POINTER (id), "default") == 0)
4648     DECL_VISIBILITY (decl) = VISIBILITY_DEFAULT;
4649   else if (strcmp (TREE_STRING_POINTER (id), "internal") == 0)
4650     DECL_VISIBILITY (decl) = VISIBILITY_INTERNAL;
4651   else if (strcmp (TREE_STRING_POINTER (id), "hidden") == 0)
4652     DECL_VISIBILITY (decl) = VISIBILITY_HIDDEN;
4653   else if (strcmp (TREE_STRING_POINTER (id), "protected") == 0)
4654     DECL_VISIBILITY (decl) = VISIBILITY_PROTECTED;
4655   else
4656     error ("visibility arg must be one of \"default\", \"hidden\", \"protected\" or \"internal\"");
4657   DECL_VISIBILITY_SPECIFIED (decl) = 1;
4658
4659   /* For decls only, go ahead and attach the attribute to the node as well.
4660      This is needed so we can determine whether we have VISIBILITY_DEFAULT
4661      because the visibility was not specified, or because it was explicitly
4662      overridden from the class visibility.  */
4663   if (DECL_P (*node))
4664     *no_add_attrs = false;
4665
4666   return NULL_TREE;
4667 }
4668
4669 /* Determine the ELF symbol visibility for DECL, which is either a
4670    variable or a function.  It is an error to use this function if a
4671    definition of DECL is not available in this translation unit.
4672    Returns true if the final visibility has been determined by this
4673    function; false if the caller is free to make additional
4674    modifications.  */
4675
4676 bool
4677 c_determine_visibility (tree decl)
4678 {
4679   gcc_assert (TREE_CODE (decl) == VAR_DECL
4680               || TREE_CODE (decl) == FUNCTION_DECL);
4681
4682   /* If the user explicitly specified the visibility with an
4683      attribute, honor that.  DECL_VISIBILITY will have been set during
4684      the processing of the attribute.  We check for an explicit
4685      attribute, rather than just checking DECL_VISIBILITY_SPECIFIED,
4686      to distinguish the use of an attribute from the use of a "#pragma
4687      GCC visibility push(...)"; in the latter case we still want other
4688      considerations to be able to overrule the #pragma.  */
4689   if (lookup_attribute ("visibility", DECL_ATTRIBUTES (decl)))
4690     return true;
4691
4692   /* Anything that is exported must have default visibility.  */
4693   if (TARGET_DLLIMPORT_DECL_ATTRIBUTES
4694       && lookup_attribute ("dllexport", DECL_ATTRIBUTES (decl)))
4695     {
4696       DECL_VISIBILITY (decl) = VISIBILITY_DEFAULT;
4697       DECL_VISIBILITY_SPECIFIED (decl) = 1;
4698       return true;
4699     }
4700
4701   return false;
4702 }
4703
4704 /* Handle an "tls_model" attribute; arguments as in
4705    struct attribute_spec.handler.  */
4706
4707 static tree
4708 handle_tls_model_attribute (tree *node, tree name, tree args,
4709                             int ARG_UNUSED (flags), bool *no_add_attrs)
4710 {
4711   tree decl = *node;
4712
4713   if (!DECL_THREAD_LOCAL (decl))
4714     {
4715       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
4716       *no_add_attrs = true;
4717     }
4718   else
4719     {
4720       tree id;
4721
4722       id = TREE_VALUE (args);
4723       if (TREE_CODE (id) != STRING_CST)
4724         {
4725           error ("tls_model arg not a string");
4726           *no_add_attrs = true;
4727           return NULL_TREE;
4728         }
4729       if (strcmp (TREE_STRING_POINTER (id), "local-exec")
4730           && strcmp (TREE_STRING_POINTER (id), "initial-exec")
4731           && strcmp (TREE_STRING_POINTER (id), "local-dynamic")
4732           && strcmp (TREE_STRING_POINTER (id), "global-dynamic"))
4733         {
4734           error ("tls_model arg must be one of \"local-exec\", \"initial-exec\", \"local-dynamic\" or \"global-dynamic\"");
4735           *no_add_attrs = true;
4736           return NULL_TREE;
4737         }
4738     }
4739
4740   return NULL_TREE;
4741 }
4742
4743 /* Handle a "no_instrument_function" attribute; arguments as in
4744    struct attribute_spec.handler.  */
4745
4746 static tree
4747 handle_no_instrument_function_attribute (tree *node, tree name,
4748                                          tree ARG_UNUSED (args),
4749                                          int ARG_UNUSED (flags),
4750                                          bool *no_add_attrs)
4751 {
4752   tree decl = *node;
4753
4754   if (TREE_CODE (decl) != FUNCTION_DECL)
4755     {
4756       error ("%J%qE attribute applies only to functions", decl, name);
4757       *no_add_attrs = true;
4758     }
4759   else if (DECL_INITIAL (decl))
4760     {
4761       error ("%Jcan%'t set %qE attribute after definition", decl, name);
4762       *no_add_attrs = true;
4763     }
4764   else
4765     DECL_NO_INSTRUMENT_FUNCTION_ENTRY_EXIT (decl) = 1;
4766
4767   return NULL_TREE;
4768 }
4769
4770 /* Handle a "malloc" attribute; arguments as in
4771    struct attribute_spec.handler.  */
4772
4773 static tree
4774 handle_malloc_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4775                          int ARG_UNUSED (flags), bool *no_add_attrs)
4776 {
4777   if (TREE_CODE (*node) == FUNCTION_DECL)
4778     DECL_IS_MALLOC (*node) = 1;
4779   /* ??? TODO: Support types.  */
4780   else
4781     {
4782       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
4783       *no_add_attrs = true;
4784     }
4785
4786   return NULL_TREE;
4787 }
4788
4789 /* Handle a "no_limit_stack" attribute; arguments as in
4790    struct attribute_spec.handler.  */
4791
4792 static tree
4793 handle_no_limit_stack_attribute (tree *node, tree name,
4794                                  tree ARG_UNUSED (args),
4795                                  int ARG_UNUSED (flags),
4796                                  bool *no_add_attrs)
4797 {
4798   tree decl = *node;
4799
4800   if (TREE_CODE (decl) != FUNCTION_DECL)
4801     {
4802       error ("%J%qE attribute applies only to functions", decl, name);
4803       *no_add_attrs = true;
4804     }
4805   else if (DECL_INITIAL (decl))
4806     {
4807       error ("%Jcan%'t set %qE attribute after definition", decl, name);
4808       *no_add_attrs = true;
4809     }
4810   else
4811     DECL_NO_LIMIT_STACK (decl) = 1;
4812
4813   return NULL_TREE;
4814 }
4815
4816 /* Handle a "pure" attribute; arguments as in
4817    struct attribute_spec.handler.  */
4818
4819 static tree
4820 handle_pure_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4821                        int ARG_UNUSED (flags), bool *no_add_attrs)
4822 {
4823   if (TREE_CODE (*node) == FUNCTION_DECL)
4824     DECL_IS_PURE (*node) = 1;
4825   /* ??? TODO: Support types.  */
4826   else
4827     {
4828       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
4829       *no_add_attrs = true;
4830     }
4831
4832   return NULL_TREE;
4833 }
4834
4835 /* Handle a "deprecated" attribute; arguments as in
4836    struct attribute_spec.handler.  */
4837
4838 static tree
4839 handle_deprecated_attribute (tree *node, tree name,
4840                              tree ARG_UNUSED (args), int flags,
4841                              bool *no_add_attrs)
4842 {
4843   tree type = NULL_TREE;
4844   int warn = 0;
4845   const char *what = NULL;
4846
4847   if (DECL_P (*node))
4848     {
4849       tree decl = *node;
4850       type = TREE_TYPE (decl);
4851
4852       if (TREE_CODE (decl) == TYPE_DECL
4853           || TREE_CODE (decl) == PARM_DECL
4854           || TREE_CODE (decl) == VAR_DECL
4855           || TREE_CODE (decl) == FUNCTION_DECL
4856           || TREE_CODE (decl) == FIELD_DECL)
4857         TREE_DEPRECATED (decl) = 1;
4858       else
4859         warn = 1;
4860     }
4861   else if (TYPE_P (*node))
4862     {
4863       if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
4864         *node = build_variant_type_copy (*node);
4865       TREE_DEPRECATED (*node) = 1;
4866       type = *node;
4867     }
4868   else
4869     warn = 1;
4870
4871   if (warn)
4872     {
4873       *no_add_attrs = true;
4874       if (type && TYPE_NAME (type))
4875         {
4876           if (TREE_CODE (TYPE_NAME (type)) == IDENTIFIER_NODE)
4877             what = IDENTIFIER_POINTER (TYPE_NAME (*node));
4878           else if (TREE_CODE (TYPE_NAME (type)) == TYPE_DECL
4879                    && DECL_NAME (TYPE_NAME (type)))
4880             what = IDENTIFIER_POINTER (DECL_NAME (TYPE_NAME (type)));
4881         }
4882       if (what)
4883         warning ("%qs attribute ignored for %qs",
4884                   IDENTIFIER_POINTER (name), what);
4885       else
4886         warning ("%qs attribute ignored",
4887                       IDENTIFIER_POINTER (name));
4888     }
4889
4890   return NULL_TREE;
4891 }
4892
4893 /* Handle a "vector_size" attribute; arguments as in
4894    struct attribute_spec.handler.  */
4895
4896 static tree
4897 handle_vector_size_attribute (tree *node, tree name, tree args,
4898                               int ARG_UNUSED (flags),
4899                               bool *no_add_attrs)
4900 {
4901   unsigned HOST_WIDE_INT vecsize, nunits;
4902   enum machine_mode orig_mode;
4903   tree type = *node, new_type, size;
4904
4905   *no_add_attrs = true;
4906
4907   /* Stripping NON_LVALUE_EXPR allows declarations such as
4908      typedef short v4si __attribute__((vector_size (4 * sizeof(short)))).  */
4909   size = TREE_VALUE (args);
4910   if (TREE_CODE (size) == NON_LVALUE_EXPR)
4911     size = TREE_OPERAND (size, 0);
4912
4913   if (!host_integerp (size, 1))
4914     {
4915       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
4916       return NULL_TREE;
4917     }
4918
4919   /* Get the vector size (in bytes).  */
4920   vecsize = tree_low_cst (size, 1);
4921
4922   /* We need to provide for vector pointers, vector arrays, and
4923      functions returning vectors.  For example:
4924
4925        __attribute__((vector_size(16))) short *foo;
4926
4927      In this case, the mode is SI, but the type being modified is
4928      HI, so we need to look further.  */
4929
4930   while (POINTER_TYPE_P (type)
4931          || TREE_CODE (type) == FUNCTION_TYPE
4932          || TREE_CODE (type) == METHOD_TYPE
4933          || TREE_CODE (type) == ARRAY_TYPE)
4934     type = TREE_TYPE (type);
4935
4936   /* Get the mode of the type being modified.  */
4937   orig_mode = TYPE_MODE (type);
4938
4939   if (TREE_CODE (type) == RECORD_TYPE
4940       || (GET_MODE_CLASS (orig_mode) != MODE_FLOAT
4941           && GET_MODE_CLASS (orig_mode) != MODE_INT)
4942       || !host_integerp (TYPE_SIZE_UNIT (type), 1))
4943     {
4944       error ("invalid vector type for attribute %qs",
4945              IDENTIFIER_POINTER (name));
4946       return NULL_TREE;
4947     }
4948
4949   /* Calculate how many units fit in the vector.  */
4950   nunits = vecsize / tree_low_cst (TYPE_SIZE_UNIT (type), 1);
4951   if (nunits & (nunits - 1))
4952     {
4953       error ("number of components of the vector not a power of two");
4954       return NULL_TREE;
4955     }
4956
4957   new_type = build_vector_type (type, nunits);
4958
4959   /* Build back pointers if needed.  */
4960   *node = reconstruct_complex_type (*node, new_type);
4961
4962   return NULL_TREE;
4963 }
4964
4965 /* Handle the "nonnull" attribute.  */
4966 static tree
4967 handle_nonnull_attribute (tree *node, tree ARG_UNUSED (name),
4968                           tree args, int ARG_UNUSED (flags),
4969                           bool *no_add_attrs)
4970 {
4971   tree type = *node;
4972   unsigned HOST_WIDE_INT attr_arg_num;
4973
4974   /* If no arguments are specified, all pointer arguments should be
4975      non-null.  Verify a full prototype is given so that the arguments
4976      will have the correct types when we actually check them later.  */
4977   if (!args)
4978     {
4979       if (!TYPE_ARG_TYPES (type))
4980         {
4981           error ("nonnull attribute without arguments on a non-prototype");
4982           *no_add_attrs = true;
4983         }
4984       return NULL_TREE;
4985     }
4986
4987   /* Argument list specified.  Verify that each argument number references
4988      a pointer argument.  */
4989   for (attr_arg_num = 1; args; args = TREE_CHAIN (args))
4990     {
4991       tree argument;
4992       unsigned HOST_WIDE_INT arg_num = 0, ck_num;
4993
4994       if (!get_nonnull_operand (TREE_VALUE (args), &arg_num))
4995         {
4996           error ("nonnull argument has invalid operand number (arg %lu)",
4997                  (unsigned long) attr_arg_num);
4998           *no_add_attrs = true;
4999           return NULL_TREE;
5000         }
5001
5002       argument = TYPE_ARG_TYPES (type);
5003       if (argument)
5004         {
5005           for (ck_num = 1; ; ck_num++)
5006             {
5007               if (!argument || ck_num == arg_num)
5008                 break;
5009               argument = TREE_CHAIN (argument);
5010             }
5011
5012           if (!argument
5013               || TREE_CODE (TREE_VALUE (argument)) == VOID_TYPE)
5014             {
5015               error ("nonnull argument with out-of-range operand number (arg %lu, operand %lu)",
5016                      (unsigned long) attr_arg_num, (unsigned long) arg_num);
5017               *no_add_attrs = true;
5018               return NULL_TREE;
5019             }
5020
5021           if (TREE_CODE (TREE_VALUE (argument)) != POINTER_TYPE)
5022             {
5023               error ("nonnull argument references non-pointer operand (arg %lu, operand %lu)",
5024                    (unsigned long) attr_arg_num, (unsigned long) arg_num);
5025               *no_add_attrs = true;
5026               return NULL_TREE;
5027             }
5028         }
5029     }
5030
5031   return NULL_TREE;
5032 }
5033
5034 /* Check the argument list of a function call for null in argument slots
5035    that are marked as requiring a non-null pointer argument.  */
5036
5037 static void
5038 check_function_nonnull (tree attrs, tree params)
5039 {
5040   tree a, args, param;
5041   int param_num;
5042
5043   for (a = attrs; a; a = TREE_CHAIN (a))
5044     {
5045       if (is_attribute_p ("nonnull", TREE_PURPOSE (a)))
5046         {
5047           args = TREE_VALUE (a);
5048
5049           /* Walk the argument list.  If we encounter an argument number we
5050              should check for non-null, do it.  If the attribute has no args,
5051              then every pointer argument is checked (in which case the check
5052              for pointer type is done in check_nonnull_arg).  */
5053           for (param = params, param_num = 1; ;
5054                param_num++, param = TREE_CHAIN (param))
5055             {
5056               if (!param)
5057         break;
5058               if (!args || nonnull_check_p (args, param_num))
5059         check_function_arguments_recurse (check_nonnull_arg, NULL,
5060                                           TREE_VALUE (param),
5061                                           param_num);
5062             }
5063         }
5064     }
5065 }
5066
5067 /* Check that the Nth argument of a function call (counting backwards
5068    from the end) is a (pointer)0.  */
5069
5070 static void
5071 check_function_sentinel (tree attrs, tree params)
5072 {
5073   tree attr = lookup_attribute ("sentinel", attrs);
5074
5075   if (attr)
5076     {
5077       if (!params)
5078         warning ("missing sentinel in function call");
5079       else
5080         {
5081           tree sentinel, end;
5082           unsigned pos = 0;
5083
5084           if (TREE_VALUE (attr))
5085             {
5086               tree p = TREE_VALUE (TREE_VALUE (attr));
5087               STRIP_NOPS (p);
5088               pos = TREE_INT_CST_LOW (p);
5089             }
5090
5091           sentinel = end = params;
5092
5093           /* Advance `end' ahead of `sentinel' by `pos' positions.  */
5094           while (pos > 0 && TREE_CHAIN (end))
5095             {
5096               pos--;
5097               end = TREE_CHAIN (end);
5098             }
5099           if (pos > 0)
5100             {
5101               warning ("not enough arguments to fit a sentinel");
5102               return;
5103             }
5104
5105           /* Now advance both until we find the last parameter.  */
5106           while (TREE_CHAIN (end))
5107             {
5108               end = TREE_CHAIN (end);
5109               sentinel = TREE_CHAIN (sentinel);
5110             }
5111
5112           /* Validate the sentinel.  */
5113           if (!POINTER_TYPE_P (TREE_TYPE (TREE_VALUE (sentinel)))
5114               || !integer_zerop (TREE_VALUE (sentinel)))
5115             warning ("missing sentinel in function call");
5116         }
5117     }
5118 }
5119
5120 /* Helper for check_function_nonnull; given a list of operands which
5121    must be non-null in ARGS, determine if operand PARAM_NUM should be
5122    checked.  */
5123
5124 static bool
5125 nonnull_check_p (tree args, unsigned HOST_WIDE_INT param_num)
5126 {
5127   unsigned HOST_WIDE_INT arg_num = 0;
5128
5129   for (; args; args = TREE_CHAIN (args))
5130     {
5131       bool found = get_nonnull_operand (TREE_VALUE (args), &arg_num);
5132
5133       gcc_assert (found);
5134
5135       if (arg_num == param_num)
5136         return true;
5137     }
5138   return false;
5139 }
5140
5141 /* Check that the function argument PARAM (which is operand number
5142    PARAM_NUM) is non-null.  This is called by check_function_nonnull
5143    via check_function_arguments_recurse.  */
5144
5145 static void
5146 check_nonnull_arg (void * ARG_UNUSED (ctx), tree param,
5147                    unsigned HOST_WIDE_INT param_num)
5148 {
5149   /* Just skip checking the argument if it's not a pointer.  This can
5150      happen if the "nonnull" attribute was given without an operand
5151      list (which means to check every pointer argument).  */
5152
5153   if (TREE_CODE (TREE_TYPE (param)) != POINTER_TYPE)
5154     return;
5155
5156   if (integer_zerop (param))
5157     warning ("null argument where non-null required (arg %lu)",
5158              (unsigned long) param_num);
5159 }
5160
5161 /* Helper for nonnull attribute handling; fetch the operand number
5162    from the attribute argument list.  */
5163
5164 static bool
5165 get_nonnull_operand (tree arg_num_expr, unsigned HOST_WIDE_INT *valp)
5166 {
5167   /* Strip any conversions from the arg number and verify they
5168      are constants.  */
5169   while (TREE_CODE (arg_num_expr) == NOP_EXPR
5170          || TREE_CODE (arg_num_expr) == CONVERT_EXPR
5171          || TREE_CODE (arg_num_expr) == NON_LVALUE_EXPR)
5172     arg_num_expr = TREE_OPERAND (arg_num_expr, 0);
5173
5174   if (TREE_CODE (arg_num_expr) != INTEGER_CST
5175       || TREE_INT_CST_HIGH (arg_num_expr) != 0)
5176     return false;
5177
5178   *valp = TREE_INT_CST_LOW (arg_num_expr);
5179   return true;
5180 }
5181
5182 /* Handle a "nothrow" attribute; arguments as in
5183    struct attribute_spec.handler.  */
5184
5185 static tree
5186 handle_nothrow_attribute (tree *node, tree name, tree ARG_UNUSED (args),
5187                           int ARG_UNUSED (flags), bool *no_add_attrs)
5188 {
5189   if (TREE_CODE (*node) == FUNCTION_DECL)
5190     TREE_NOTHROW (*node) = 1;
5191   /* ??? TODO: Support types.  */
5192   else
5193     {
5194       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
5195       *no_add_attrs = true;
5196     }
5197
5198   return NULL_TREE;
5199 }
5200
5201 /* Handle a "cleanup" attribute; arguments as in
5202    struct attribute_spec.handler.  */
5203
5204 static tree
5205 handle_cleanup_attribute (tree *node, tree name, tree args,
5206                           int ARG_UNUSED (flags), bool *no_add_attrs)
5207 {
5208   tree decl = *node;
5209   tree cleanup_id, cleanup_decl;
5210
5211   /* ??? Could perhaps support cleanups on TREE_STATIC, much like we do
5212      for global destructors in C++.  This requires infrastructure that
5213      we don't have generically at the moment.  It's also not a feature
5214      we'd be missing too much, since we do have attribute constructor.  */
5215   if (TREE_CODE (decl) != VAR_DECL || TREE_STATIC (decl))
5216     {
5217       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
5218       *no_add_attrs = true;
5219       return NULL_TREE;
5220     }
5221
5222   /* Verify that the argument is a function in scope.  */
5223   /* ??? We could support pointers to functions here as well, if
5224      that was considered desirable.  */
5225   cleanup_id = TREE_VALUE (args);
5226   if (TREE_CODE (cleanup_id) != IDENTIFIER_NODE)
5227     {
5228       error ("cleanup arg not an identifier");
5229       *no_add_attrs = true;
5230       return NULL_TREE;
5231     }
5232   cleanup_decl = lookup_name (cleanup_id);
5233   if (!cleanup_decl || TREE_CODE (cleanup_decl) != FUNCTION_DECL)
5234     {
5235       error ("cleanup arg not a function");
5236       *no_add_attrs = true;
5237       return NULL_TREE;
5238     }
5239
5240   /* That the function has proper type is checked with the
5241      eventual call to build_function_call.  */
5242
5243   return NULL_TREE;
5244 }
5245
5246 /* Handle a "warn_unused_result" attribute.  No special handling.  */
5247
5248 static tree
5249 handle_warn_unused_result_attribute (tree *node, tree name,
5250                                tree ARG_UNUSED (args),
5251                                int ARG_UNUSED (flags), bool *no_add_attrs)
5252 {
5253   /* Ignore the attribute for functions not returning any value.  */
5254   if (VOID_TYPE_P (TREE_TYPE (*node)))
5255     {
5256       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
5257       *no_add_attrs = true;
5258     }
5259
5260   return NULL_TREE;
5261 }
5262
5263 /* Handle a "sentinel" attribute.  */
5264
5265 static tree
5266 handle_sentinel_attribute (tree *node, tree name, tree args,
5267                            int ARG_UNUSED (flags), bool *no_add_attrs)
5268 {
5269   tree params = TYPE_ARG_TYPES (*node);
5270
5271   if (!params)
5272     {
5273       warning ("%qs attribute requires prototypes with named arguments",
5274                IDENTIFIER_POINTER (name));
5275       *no_add_attrs = true;
5276     }
5277   else
5278     {
5279       while (TREE_CHAIN (params))
5280         params = TREE_CHAIN (params);
5281
5282       if (VOID_TYPE_P (TREE_VALUE (params)))
5283         {
5284           warning ("%qs attribute only applies to variadic functions",
5285                    IDENTIFIER_POINTER (name));
5286           *no_add_attrs = true;
5287         }
5288     }
5289
5290   if (args)
5291     {
5292       tree position = TREE_VALUE (args);
5293
5294       STRIP_NOPS (position);
5295       if (TREE_CODE (position) != INTEGER_CST)
5296         {
5297           warning ("requested position is not an integer constant");
5298           *no_add_attrs = true;
5299         }
5300       else
5301         {
5302           if (tree_int_cst_lt (position, integer_zero_node))
5303             {
5304               warning ("requested position is less than zero");
5305               *no_add_attrs = true;
5306             }
5307         }
5308     }
5309
5310   return NULL_TREE;
5311 }
5312 \f
5313 /* Check for valid arguments being passed to a function.  */
5314 void
5315 check_function_arguments (tree attrs, tree params)
5316 {
5317   /* Check for null being passed in a pointer argument that must be
5318      non-null.  We also need to do this if format checking is enabled.  */
5319
5320   if (warn_nonnull)
5321     check_function_nonnull (attrs, params);
5322
5323   /* Check for errors in format strings.  */
5324
5325   if (warn_format)
5326     {
5327       check_function_format (attrs, params);
5328       check_function_sentinel (attrs, params);
5329     }
5330 }
5331
5332 /* Generic argument checking recursion routine.  PARAM is the argument to
5333    be checked.  PARAM_NUM is the number of the argument.  CALLBACK is invoked
5334    once the argument is resolved.  CTX is context for the callback.  */
5335 void
5336 check_function_arguments_recurse (void (*callback)
5337                                   (void *, tree, unsigned HOST_WIDE_INT),
5338                                   void *ctx, tree param,
5339                                   unsigned HOST_WIDE_INT param_num)
5340 {
5341   if (TREE_CODE (param) == NOP_EXPR)
5342     {
5343       /* Strip coercion.  */
5344       check_function_arguments_recurse (callback, ctx,
5345                                         TREE_OPERAND (param, 0), param_num);
5346       return;
5347     }
5348
5349   if (TREE_CODE (param) == CALL_EXPR)
5350     {
5351       tree type = TREE_TYPE (TREE_TYPE (TREE_OPERAND (param, 0)));
5352       tree attrs;
5353       bool found_format_arg = false;
5354
5355       /* See if this is a call to a known internationalization function
5356          that modifies a format arg.  Such a function may have multiple
5357          format_arg attributes (for example, ngettext).  */
5358
5359       for (attrs = TYPE_ATTRIBUTES (type);
5360            attrs;
5361            attrs = TREE_CHAIN (attrs))
5362         if (is_attribute_p ("format_arg", TREE_PURPOSE (attrs)))
5363           {
5364             tree inner_args;
5365             tree format_num_expr;
5366             int format_num;
5367             int i;
5368
5369             /* Extract the argument number, which was previously checked
5370                to be valid.  */
5371             format_num_expr = TREE_VALUE (TREE_VALUE (attrs));
5372             while (TREE_CODE (format_num_expr) == NOP_EXPR
5373                    || TREE_CODE (format_num_expr) == CONVERT_EXPR
5374                    || TREE_CODE (format_num_expr) == NON_LVALUE_EXPR)
5375               format_num_expr = TREE_OPERAND (format_num_expr, 0);
5376
5377             gcc_assert (TREE_CODE (format_num_expr) == INTEGER_CST
5378                         && !TREE_INT_CST_HIGH (format_num_expr));
5379
5380             format_num = TREE_INT_CST_LOW (format_num_expr);
5381
5382             for (inner_args = TREE_OPERAND (param, 1), i = 1;
5383                  inner_args != 0;
5384                  inner_args = TREE_CHAIN (inner_args), i++)
5385               if (i == format_num)
5386                 {
5387                   check_function_arguments_recurse (callback, ctx,
5388                                                     TREE_VALUE (inner_args),
5389                                                     param_num);
5390                   found_format_arg = true;
5391                   break;
5392                 }
5393           }
5394
5395       /* If we found a format_arg attribute and did a recursive check,
5396          we are done with checking this argument.  Otherwise, we continue
5397          and this will be considered a non-literal.  */
5398       if (found_format_arg)
5399         return;
5400     }
5401
5402   if (TREE_CODE (param) == COND_EXPR)
5403     {
5404       /* Check both halves of the conditional expression.  */
5405       check_function_arguments_recurse (callback, ctx,
5406                                         TREE_OPERAND (param, 1), param_num);
5407       check_function_arguments_recurse (callback, ctx,
5408                                         TREE_OPERAND (param, 2), param_num);
5409       return;
5410     }
5411
5412   (*callback) (ctx, param, param_num);
5413 }
5414
5415 /* Function to help qsort sort FIELD_DECLs by name order.  */
5416
5417 int
5418 field_decl_cmp (const void *x_p, const void *y_p)
5419 {
5420   const tree *const x = (const tree *const) x_p;
5421   const tree *const y = (const tree *const) y_p;
5422
5423   if (DECL_NAME (*x) == DECL_NAME (*y))
5424     /* A nontype is "greater" than a type.  */
5425     return (TREE_CODE (*y) == TYPE_DECL) - (TREE_CODE (*x) == TYPE_DECL);
5426   if (DECL_NAME (*x) == NULL_TREE)
5427     return -1;
5428   if (DECL_NAME (*y) == NULL_TREE)
5429     return 1;
5430   if (DECL_NAME (*x) < DECL_NAME (*y))
5431     return -1;
5432   return 1;
5433 }
5434
5435 static struct {
5436   gt_pointer_operator new_value;
5437   void *cookie;
5438 } resort_data;
5439
5440 /* This routine compares two fields like field_decl_cmp but using the
5441 pointer operator in resort_data.  */
5442
5443 static int
5444 resort_field_decl_cmp (const void *x_p, const void *y_p)
5445 {
5446   const tree *const x = (const tree *const) x_p;
5447   const tree *const y = (const tree *const) y_p;
5448
5449   if (DECL_NAME (*x) == DECL_NAME (*y))
5450     /* A nontype is "greater" than a type.  */
5451     return (TREE_CODE (*y) == TYPE_DECL) - (TREE_CODE (*x) == TYPE_DECL);
5452   if (DECL_NAME (*x) == NULL_TREE)
5453     return -1;
5454   if (DECL_NAME (*y) == NULL_TREE)
5455     return 1;
5456   {
5457     tree d1 = DECL_NAME (*x);
5458     tree d2 = DECL_NAME (*y);
5459     resort_data.new_value (&d1, resort_data.cookie);
5460     resort_data.new_value (&d2, resort_data.cookie);
5461     if (d1 < d2)
5462       return -1;
5463   }
5464   return 1;
5465 }
5466
5467 /* Resort DECL_SORTED_FIELDS because pointers have been reordered.  */
5468
5469 void
5470 resort_sorted_fields (void *obj,
5471                       void * ARG_UNUSED (orig_obj),
5472                       gt_pointer_operator new_value,
5473                       void *cookie)
5474 {
5475   struct sorted_fields_type *sf = (struct sorted_fields_type *) obj;
5476   resort_data.new_value = new_value;
5477   resort_data.cookie = cookie;
5478   qsort (&sf->elts[0], sf->len, sizeof (tree),
5479          resort_field_decl_cmp);
5480 }
5481
5482 /* Subroutine of c_parse_error.
5483    Return the result of concatenating LHS and RHS. RHS is really
5484    a string literal, its first character is indicated by RHS_START and
5485    RHS_SIZE is its length (including the terminating NUL character).
5486
5487    The caller is responsible for deleting the returned pointer.  */
5488
5489 static char *
5490 catenate_strings (const char *lhs, const char *rhs_start, int rhs_size)
5491 {
5492   const int lhs_size = strlen (lhs);
5493   char *result = XNEWVEC (char, lhs_size + rhs_size);
5494   strncpy (result, lhs, lhs_size);
5495   strncpy (result + lhs_size, rhs_start, rhs_size);
5496   return result;
5497 }
5498
5499 /* Issue the error given by MSGID, indicating that it occurred before
5500    TOKEN, which had the associated VALUE.  */
5501
5502 void
5503 c_parse_error (const char *msgid, enum cpp_ttype token, tree value)
5504 {
5505 #define catenate_messages(M1, M2) catenate_strings ((M1), (M2), sizeof (M2))
5506
5507   char *message = NULL;
5508
5509   if (token == CPP_EOF)
5510     message = catenate_messages (msgid, " at end of input");
5511   else if (token == CPP_CHAR || token == CPP_WCHAR)
5512     {
5513       unsigned int val = TREE_INT_CST_LOW (value);
5514       const char *const ell = (token == CPP_CHAR) ? "" : "L";
5515       if (val <= UCHAR_MAX && ISGRAPH (val))
5516         message = catenate_messages (msgid, " before %s'%c'");
5517       else
5518         message = catenate_messages (msgid, " before %s'\\x%x'");
5519
5520       error (message, ell, val);
5521       free (message);
5522       message = NULL;
5523     }
5524   else if (token == CPP_STRING || token == CPP_WSTRING)
5525     message = catenate_messages (msgid, " before string constant");
5526   else if (token == CPP_NUMBER)
5527     message = catenate_messages (msgid, " before numeric constant");
5528   else if (token == CPP_NAME)
5529     {
5530       message = catenate_messages (msgid, " before %qs");
5531       error (message, IDENTIFIER_POINTER (value));
5532       free (message);
5533       message = NULL;
5534     }
5535   else if (token < N_TTYPES)
5536     {
5537       message = catenate_messages (msgid, " before %qs token");
5538       error (message, cpp_type2name (token));
5539       free (message);
5540       message = NULL;
5541     }
5542   else
5543     error (msgid);
5544
5545   if (message)
5546     {
5547       error (message);
5548       free (message);
5549     }
5550 #undef catenate_messages
5551 }
5552
5553 /* Walk a gimplified function and warn for functions whose return value is
5554    ignored and attribute((warn_unused_result)) is set.  This is done before
5555    inlining, so we don't have to worry about that.  */
5556
5557 void
5558 c_warn_unused_result (tree *top_p)
5559 {
5560   tree t = *top_p;
5561   tree_stmt_iterator i;
5562   tree fdecl, ftype;
5563
5564   switch (TREE_CODE (t))
5565     {
5566     case STATEMENT_LIST:
5567       for (i = tsi_start (*top_p); !tsi_end_p (i); tsi_next (&i))
5568         c_warn_unused_result (tsi_stmt_ptr (i));
5569       break;
5570
5571     case COND_EXPR:
5572       c_warn_unused_result (&COND_EXPR_THEN (t));
5573       c_warn_unused_result (&COND_EXPR_ELSE (t));
5574       break;
5575     case BIND_EXPR:
5576       c_warn_unused_result (&BIND_EXPR_BODY (t));
5577       break;
5578     case TRY_FINALLY_EXPR:
5579     case TRY_CATCH_EXPR:
5580       c_warn_unused_result (&TREE_OPERAND (t, 0));
5581       c_warn_unused_result (&TREE_OPERAND (t, 1));
5582       break;
5583     case CATCH_EXPR:
5584       c_warn_unused_result (&CATCH_BODY (t));
5585       break;
5586     case EH_FILTER_EXPR:
5587       c_warn_unused_result (&EH_FILTER_FAILURE (t));
5588       break;
5589
5590     case CALL_EXPR:
5591       if (TREE_USED (t))
5592         break;
5593
5594       /* This is a naked call, as opposed to a CALL_EXPR nested inside
5595          a MODIFY_EXPR.  All calls whose value is ignored should be
5596          represented like this.  Look for the attribute.  */
5597       fdecl = get_callee_fndecl (t);
5598       if (fdecl)
5599         ftype = TREE_TYPE (fdecl);
5600       else
5601         {
5602           ftype = TREE_TYPE (TREE_OPERAND (t, 0));
5603           /* Look past pointer-to-function to the function type itself.  */
5604           ftype = TREE_TYPE (ftype);
5605         }
5606
5607       if (lookup_attribute ("warn_unused_result", TYPE_ATTRIBUTES (ftype)))
5608         {
5609           if (fdecl)
5610             warning ("%Hignoring return value of %qD, "
5611                      "declared with attribute warn_unused_result",
5612                      EXPR_LOCUS (t), fdecl);
5613           else
5614             warning ("%Hignoring return value of function "
5615                      "declared with attribute warn_unused_result",
5616                      EXPR_LOCUS (t));
5617         }
5618       break;
5619
5620     default:
5621       /* Not a container, not a call, or a call whose value is used.  */
5622       break;
5623     }
5624 }
5625
5626 /* Build the result of __builtin_offsetof.  EXPR is a nested sequence of
5627    component references, with an INDIRECT_REF at the bottom; much like
5628    the traditional rendering of offsetof as a macro.  Returns the folded
5629    and properly cast result.  */
5630
5631 static tree
5632 fold_offsetof_1 (tree expr)
5633 {
5634   enum tree_code code = PLUS_EXPR;
5635   tree base, off, t;
5636
5637   switch (TREE_CODE (expr))
5638     {
5639     case ERROR_MARK:
5640       return expr;
5641
5642     case INDIRECT_REF:
5643       return size_zero_node;
5644
5645     case COMPONENT_REF:
5646       base = fold_offsetof_1 (TREE_OPERAND (expr, 0));
5647       if (base == error_mark_node)
5648         return base;
5649
5650       t = TREE_OPERAND (expr, 1);
5651       if (DECL_C_BIT_FIELD (t))
5652         {
5653           error ("attempt to take address of bit-field structure "
5654                  "member %qs", IDENTIFIER_POINTER (DECL_NAME (t)));
5655           return error_mark_node;
5656         }
5657       off = size_binop (PLUS_EXPR, DECL_FIELD_OFFSET (t),
5658                         size_int (tree_low_cst (DECL_FIELD_BIT_OFFSET (t), 1)
5659                                   / BITS_PER_UNIT));
5660       break;
5661
5662     case ARRAY_REF:
5663       base = fold_offsetof_1 (TREE_OPERAND (expr, 0));
5664       if (base == error_mark_node)
5665         return base;
5666
5667       t = TREE_OPERAND (expr, 1);
5668       if (TREE_CODE (t) == INTEGER_CST && tree_int_cst_sgn (t) < 0)
5669         {
5670           code = MINUS_EXPR;
5671           t = fold (build1 (NEGATE_EXPR, TREE_TYPE (t), t));
5672         }
5673       t = convert (sizetype, t);
5674       off = size_binop (MULT_EXPR, TYPE_SIZE_UNIT (TREE_TYPE (expr)), t);
5675       break;
5676
5677     default:
5678       gcc_unreachable ();
5679     }
5680
5681   return size_binop (code, base, off);
5682 }
5683
5684 tree
5685 fold_offsetof (tree expr)
5686 {
5687   /* Convert back from the internal sizetype to size_t.  */
5688   return convert (size_type_node, fold_offsetof_1 (expr));
5689 }
5690
5691 #include "gt-c-common.h"