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, 2005 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, 51 Franklin Street, Fifth Floor, Boston, MA
  20 02110-1301, 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 #include "real.h"
  50 #include "cgraph.h"
  51
  52 cpp_reader *parse_in;           /* Declared in c-pragma.h.  */
  53
  54 /* We let tm.h override the types used here, to handle trivial differences
  55    such as the choice of unsigned int or long unsigned int for size_t.
  56    When machines start needing nontrivial differences in the size type,
  57    it would be best to do something here to figure out automatically
  58    from other information what type to use.  */
  59
  60 #ifndef SIZE_TYPE
  61 #define SIZE_TYPE "long unsigned int"
  62 #endif
  63
  64 #ifndef PID_TYPE
  65 #define PID_TYPE "int"
  66 #endif
  67
  68 #ifndef WCHAR_TYPE
  69 #define WCHAR_TYPE "int"
  70 #endif
  71
  72 /* WCHAR_TYPE gets overridden by -fshort-wchar.  */
  73 #define MODIFIED_WCHAR_TYPE \
  74         (flag_short_wchar ? "short unsigned int" : WCHAR_TYPE)
  75
  76 #ifndef PTRDIFF_TYPE
  77 #define PTRDIFF_TYPE "long int"
  78 #endif
  79
  80 #ifndef WINT_TYPE
  81 #define WINT_TYPE "unsigned int"
  82 #endif
  83
  84 #ifndef INTMAX_TYPE
  85 #define INTMAX_TYPE ((INT_TYPE_SIZE == LONG_LONG_TYPE_SIZE)     \
  86                      ? "int"                                    \
  87                      : ((LONG_TYPE_SIZE == LONG_LONG_TYPE_SIZE) \
  88                         ? "long int"                            \
  89                         : "long long int"))
  90 #endif
  91
  92 #ifndef UINTMAX_TYPE
  93 #define UINTMAX_TYPE ((INT_TYPE_SIZE == LONG_LONG_TYPE_SIZE)    \
  94                      ? "unsigned int"                           \
  95                      : ((LONG_TYPE_SIZE == LONG_LONG_TYPE_SIZE) \
  96                         ? "long unsigned int"                   \
  97                         : "long long unsigned int"))
  98 #endif
  99
 100 /* The following symbols are subsumed in the c_global_trees array, and
 101    listed here individually for documentation purposes.
 102
 103    INTEGER_TYPE and REAL_TYPE nodes for the standard data types.
 104
 105         tree short_integer_type_node;
 106         tree long_integer_type_node;
 107         tree long_long_integer_type_node;
 108
 109         tree short_unsigned_type_node;
 110         tree long_unsigned_type_node;
 111         tree long_long_unsigned_type_node;
 112
 113         tree truthvalue_type_node;
 114         tree truthvalue_false_node;
 115         tree truthvalue_true_node;
 116
 117         tree ptrdiff_type_node;
 118
 119         tree unsigned_char_type_node;
 120         tree signed_char_type_node;
 121         tree wchar_type_node;
 122         tree signed_wchar_type_node;
 123         tree unsigned_wchar_type_node;
 124
 125         tree float_type_node;
 126         tree double_type_node;
 127         tree long_double_type_node;
 128
 129         tree complex_integer_type_node;
 130         tree complex_float_type_node;
 131         tree complex_double_type_node;
 132         tree complex_long_double_type_node;
 133
 134         tree dfloat32_type_node;
 135         tree dfloat64_type_node;
 136         tree_dfloat128_type_node;
 137
 138         tree intQI_type_node;
 139         tree intHI_type_node;
 140         tree intSI_type_node;
 141         tree intDI_type_node;
 142         tree intTI_type_node;
 143
 144         tree unsigned_intQI_type_node;
 145         tree unsigned_intHI_type_node;
 146         tree unsigned_intSI_type_node;
 147         tree unsigned_intDI_type_node;
 148         tree unsigned_intTI_type_node;
 149
 150         tree widest_integer_literal_type_node;
 151         tree widest_unsigned_literal_type_node;
 152
 153    Nodes for types `void *' and `const void *'.
 154
 155         tree ptr_type_node, const_ptr_type_node;
 156
 157    Nodes for types `char *' and `const char *'.
 158
 159         tree string_type_node, const_string_type_node;
 160
 161    Type `char[SOMENUMBER]'.
 162    Used when an array of char is needed and the size is irrelevant.
 163
 164         tree char_array_type_node;
 165
 166    Type `int[SOMENUMBER]' or something like it.
 167    Used when an array of int needed and the size is irrelevant.
 168
 169         tree int_array_type_node;
 170
 171    Type `wchar_t[SOMENUMBER]' or something like it.
 172    Used when a wide string literal is created.
 173
 174         tree wchar_array_type_node;
 175
 176    Type `int ()' -- used for implicit declaration of functions.
 177
 178         tree default_function_type;
 179
 180    A VOID_TYPE node, packaged in a TREE_LIST.
 181
 182         tree void_list_node;
 183
 184   The lazily created VAR_DECLs for __FUNCTION__, __PRETTY_FUNCTION__,
 185   and __func__. (C doesn't generate __FUNCTION__ and__PRETTY_FUNCTION__
 186   VAR_DECLS, but C++ does.)
 187
 188         tree function_name_decl_node;
 189         tree pretty_function_name_decl_node;
 190         tree c99_function_name_decl_node;
 191
 192   Stack of nested function name VAR_DECLs.
 193
 194         tree saved_function_name_decls;
 195
 196 */
 197
 198 tree c_global_trees[CTI_MAX];
 199 \f
 200 /* Switches common to the C front ends.  */
 201
 202 /* Nonzero if prepreprocessing only.  */
 203
 204 int flag_preprocess_only;
 205
 206 /* Nonzero means don't output line number information.  */
 207
 208 char flag_no_line_commands;
 209
 210 /* Nonzero causes -E output not to be done, but directives such as
 211    #define that have side effects are still obeyed.  */
 212
 213 char flag_no_output;
 214
 215 /* Nonzero means dump macros in some fashion.  */
 216
 217 char flag_dump_macros;
 218
 219 /* Nonzero means pass #include lines through to the output.  */
 220
 221 char flag_dump_includes;
 222
 223 /* Nonzero means process PCH files while preprocessing.  */
 224
 225 bool flag_pch_preprocess;
 226
 227 /* The file name to which we should write a precompiled header, or
 228    NULL if no header will be written in this compile.  */
 229
 230 const char *pch_file;
 231
 232 /* Nonzero if an ISO standard was selected.  It rejects macros in the
 233    user's namespace.  */
 234 int flag_iso;
 235
 236 /* Nonzero if -undef was given.  It suppresses target built-in macros
 237    and assertions.  */
 238 int flag_undef;
 239
 240 /* Nonzero means don't recognize the non-ANSI builtin functions.  */
 241
 242 int flag_no_builtin;
 243
 244 /* Nonzero means don't recognize the non-ANSI builtin functions.
 245    -ansi sets this.  */
 246
 247 int flag_no_nonansi_builtin;
 248
 249 /* Nonzero means give `double' the same size as `float'.  */
 250
 251 int flag_short_double;
 252
 253 /* Nonzero means give `wchar_t' the same size as `short'.  */
 254
 255 int flag_short_wchar;
 256
 257 /* Nonzero means allow Microsoft extensions without warnings or errors.  */
 258 int flag_ms_extensions;
 259
 260 /* Nonzero means don't recognize the keyword `asm'.  */
 261
 262 int flag_no_asm;
 263
 264 /* Nonzero means to treat bitfields as signed unless they say `unsigned'.  */
 265
 266 int flag_signed_bitfields = 1;
 267
 268 /* Warn about #pragma directives that are not recognized.  */
 269
 270 int warn_unknown_pragmas; /* Tri state variable.  */
 271
 272 /* Warn about format/argument anomalies in calls to formatted I/O functions
 273    (*printf, *scanf, strftime, strfmon, etc.).  */
 274
 275 int warn_format;
 276
 277 /* Warn about using __null (as NULL in C++) as sentinel.  For code compiled
 278    with GCC this doesn't matter as __null is guaranteed to have the right
 279    size.  */
 280
 281 int warn_strict_null_sentinel;
 282
 283 /* Zero means that faster, ...NonNil variants of objc_msgSend...
 284    calls will be used in ObjC; passing nil receivers to such calls
 285    will most likely result in crashes.  */
 286 int flag_nil_receivers = 1;
 287
 288 /* Nonzero means that code generation will be altered to support
 289    "zero-link" execution.  This currently affects ObjC only, but may
 290    affect other languages in the future.  */
 291 int flag_zero_link = 0;
 292
 293 /* Nonzero means emit an '__OBJC, __image_info' for the current translation
 294    unit.  It will inform the ObjC runtime that class definition(s) herein
 295    contained are to replace one(s) previously loaded.  */
 296 int flag_replace_objc_classes = 0;
 297
 298 /* C/ObjC language option variables.  */
 299
 300
 301 /* Nonzero means allow type mismatches in conditional expressions;
 302    just make their values `void'.  */
 303
 304 int flag_cond_mismatch;
 305
 306 /* Nonzero means enable C89 Amendment 1 features.  */
 307
 308 int flag_isoc94;
 309
 310 /* Nonzero means use the ISO C99 dialect of C.  */
 311
 312 int flag_isoc99;
 313
 314 /* Nonzero means that we have builtin functions, and main is an int.  */
 315
 316 int flag_hosted = 1;
 317
 318 /* Warn if main is suspicious.  */
 319
 320 int warn_main;
 321
 322
 323 /* ObjC language option variables.  */
 324
 325
 326 /* Open and close the file for outputting class declarations, if
 327    requested (ObjC).  */
 328
 329 int flag_gen_declaration;
 330
 331 /* Tells the compiler that this is a special run.  Do not perform any
 332    compiling, instead we are to test some platform dependent features
 333    and output a C header file with appropriate definitions.  */
 334
 335 int print_struct_values;
 336
 337 /* Tells the compiler what is the constant string class for Objc.  */
 338
 339 const char *constant_string_class_name;
 340
 341
 342 /* C++ language option variables.  */
 343
 344
 345 /* Nonzero means don't recognize any extension keywords.  */
 346
 347 int flag_no_gnu_keywords;
 348
 349 /* Nonzero means do emit exported implementations of functions even if
 350    they can be inlined.  */
 351
 352 int flag_implement_inlines = 1;
 353
 354 /* Nonzero means that implicit instantiations will be emitted if needed.  */
 355
 356 int flag_implicit_templates = 1;
 357
 358 /* Nonzero means that implicit instantiations of inline templates will be
 359    emitted if needed, even if instantiations of non-inline templates
 360    aren't.  */
 361
 362 int flag_implicit_inline_templates = 1;
 363
 364 /* Nonzero means generate separate instantiation control files and
 365    juggle them at link time.  */
 366
 367 int flag_use_repository;
 368
 369 /* Nonzero if we want to issue diagnostics that the standard says are not
 370    required.  */
 371
 372 int flag_optional_diags = 1;
 373
 374 /* Nonzero means we should attempt to elide constructors when possible.  */
 375
 376 int flag_elide_constructors = 1;
 377
 378 /* Nonzero means that member functions defined in class scope are
 379    inline by default.  */
 380
 381 int flag_default_inline = 1;
 382
 383 /* Controls whether compiler generates 'type descriptor' that give
 384    run-time type information.  */
 385
 386 int flag_rtti = 1;
 387
 388 /* Nonzero if we want to conserve space in the .o files.  We do this
 389    by putting uninitialized data and runtime initialized data into
 390    .common instead of .data at the expense of not flagging multiple
 391    definitions.  */
 392
 393 int flag_conserve_space;
 394
 395 /* Nonzero if we want to obey access control semantics.  */
 396
 397 int flag_access_control = 1;
 398
 399 /* Nonzero if we want to check the return value of new and avoid calling
 400    constructors if it is a null pointer.  */
 401
 402 int flag_check_new;
 403
 404 /* Nonzero if we want the new ISO rules for pushing a new scope for `for'
 405    initialization variables.
 406    0: Old rules, set by -fno-for-scope.
 407    2: New ISO rules, set by -ffor-scope.
 408    1: Try to implement new ISO rules, but with backup compatibility
 409    (and warnings).  This is the default, for now.  */
 410
 411 int flag_new_for_scope = 1;
 412
 413 /* Nonzero if we want to emit defined symbols with common-like linkage as
 414    weak symbols where possible, in order to conform to C++ semantics.
 415    Otherwise, emit them as local symbols.  */
 416
 417 int flag_weak = 1;
 418
 419 /* 0 means we want the preprocessor to not emit line directives for
 420    the current working directory.  1 means we want it to do it.  -1
 421    means we should decide depending on whether debugging information
 422    is being emitted or not.  */
 423
 424 int flag_working_directory = -1;
 425
 426 /* Nonzero to use __cxa_atexit, rather than atexit, to register
 427    destructors for local statics and global objects.  '2' means it has been
 428    set nonzero as a default, not by a command-line flag.  */
 429
 430 int flag_use_cxa_atexit = DEFAULT_USE_CXA_ATEXIT;
 431
 432 /* Nonzero to use __cxa_get_exception_ptr in C++ exception-handling
 433    code.  '2' means it has not been set explicitly on the command line.  */
 434
 435 int flag_use_cxa_get_exception_ptr = 2;
 436
 437 /* Nonzero means make the default pedwarns warnings instead of errors.
 438    The value of this flag is ignored if -pedantic is specified.  */
 439
 440 int flag_permissive;
 441
 442 /* Nonzero means to implement standard semantics for exception
 443    specifications, calling unexpected if an exception is thrown that
 444    doesn't match the specification.  Zero means to treat them as
 445    assertions and optimize accordingly, but not check them.  */
 446
 447 int flag_enforce_eh_specs = 1;
 448
 449 /* Nonzero means to generate thread-safe code for initializing local
 450    statics.  */
 451
 452 int flag_threadsafe_statics = 1;
 453
 454 /* Nonzero means warn about implicit declarations.  */
 455
 456 int warn_implicit = 1;
 457
 458 /* Maximum template instantiation depth.  This limit is rather
 459    arbitrary, but it exists to limit the time it takes to notice
 460    infinite template instantiations.  */
 461
 462 int max_tinst_depth = 500;
 463
 464
 465
 466 /* The elements of `ridpointers' are identifier nodes for the reserved
 467    type names and storage classes.  It is indexed by a RID_... value.  */
 468 tree *ridpointers;
 469
 470 tree (*make_fname_decl) (tree, int);
 471
 472 /* Nonzero means the expression being parsed will never be evaluated.
 473    This is a count, since unevaluated expressions can nest.  */
 474 int skip_evaluation;
 475
 476 /* Information about how a function name is generated.  */
 477 struct fname_var_t
 478 {
 479   tree *const decl;     /* pointer to the VAR_DECL.  */
 480   const unsigned rid;   /* RID number for the identifier.  */
 481   const int pretty;     /* How pretty is it? */
 482 };
 483
 484 /* The three ways of getting then name of the current function.  */
 485
 486 const struct fname_var_t fname_vars[] =
 487 {
 488   /* C99 compliant __func__, must be first.  */
 489   {&c99_function_name_decl_node, RID_C99_FUNCTION_NAME, 0},
 490   /* GCC __FUNCTION__ compliant.  */
 491   {&function_name_decl_node, RID_FUNCTION_NAME, 0},
 492   /* GCC __PRETTY_FUNCTION__ compliant.  */
 493   {&pretty_function_name_decl_node, RID_PRETTY_FUNCTION_NAME, 1},
 494   {NULL, 0, 0},
 495 };
 496
 497 static int constant_fits_type_p (tree, tree);
 498 static tree check_case_value (tree);
 499 static bool check_case_bounds (tree, tree, tree *, tree *);
 500
 501 static tree handle_packed_attribute (tree *, tree, tree, int, bool *);
 502 static tree handle_nocommon_attribute (tree *, tree, tree, int, bool *);
 503 static tree handle_common_attribute (tree *, tree, tree, int, bool *);
 504 static tree handle_noreturn_attribute (tree *, tree, tree, int, bool *);
 505 static tree handle_noinline_attribute (tree *, tree, tree, int, bool *);
 506 static tree handle_always_inline_attribute (tree *, tree, tree, int,
 507                                             bool *);
 508 static tree handle_flatten_attribute (tree *, tree, tree, int, bool *);
 509 static tree handle_used_attribute (tree *, tree, tree, int, bool *);
 510 static tree handle_unused_attribute (tree *, tree, tree, int, bool *);
 511 static tree handle_externally_visible_attribute (tree *, tree, tree, int,
 512                                                  bool *);
 513 static tree handle_const_attribute (tree *, tree, tree, int, bool *);
 514 static tree handle_transparent_union_attribute (tree *, tree, tree,
 515                                                 int, bool *);
 516 static tree handle_constructor_attribute (tree *, tree, tree, int, bool *);
 517 static tree handle_destructor_attribute (tree *, tree, tree, int, bool *);
 518 static tree handle_mode_attribute (tree *, tree, tree, int, bool *);
 519 static tree handle_section_attribute (tree *, tree, tree, int, bool *);
 520 static tree handle_aligned_attribute (tree *, tree, tree, int, bool *);
 521 static tree handle_weak_attribute (tree *, tree, tree, int, bool *) ;
 522 static tree handle_alias_attribute (tree *, tree, tree, int, bool *);
 523 static tree handle_weakref_attribute (tree *, tree, tree, int, bool *) ;
 524 static tree handle_visibility_attribute (tree *, tree, tree, int,
 525                                          bool *);
 526 static tree handle_tls_model_attribute (tree *, tree, tree, int,
 527                                         bool *);
 528 static tree handle_no_instrument_function_attribute (tree *, tree,
 529                                                      tree, int, bool *);
 530 static tree handle_malloc_attribute (tree *, tree, tree, int, bool *);
 531 static tree handle_returns_twice_attribute (tree *, tree, tree, int, bool *);
 532 static tree handle_no_limit_stack_attribute (tree *, tree, tree, int,
 533                                              bool *);
 534 static tree handle_pure_attribute (tree *, tree, tree, int, bool *);
 535 static tree handle_novops_attribute (tree *, tree, tree, int, bool *);
 536 static tree handle_deprecated_attribute (tree *, tree, tree, int,
 537                                          bool *);
 538 static tree handle_vector_size_attribute (tree *, tree, tree, int,
 539                                           bool *);
 540 static tree handle_nonnull_attribute (tree *, tree, tree, int, bool *);
 541 static tree handle_nothrow_attribute (tree *, tree, tree, int, bool *);
 542 static tree handle_cleanup_attribute (tree *, tree, tree, int, bool *);
 543 static tree handle_warn_unused_result_attribute (tree *, tree, tree, int,
 544                                                  bool *);
 545 static tree handle_sentinel_attribute (tree *, tree, tree, int, bool *);
 546
 547 static void check_function_nonnull (tree, tree);
 548 static void check_nonnull_arg (void *, tree, unsigned HOST_WIDE_INT);
 549 static bool nonnull_check_p (tree, unsigned HOST_WIDE_INT);
 550 static bool get_nonnull_operand (tree, unsigned HOST_WIDE_INT *);
 551 static int resort_field_decl_cmp (const void *, const void *);
 552
 553 /* Table of machine-independent attributes common to all C-like languages.  */
 554 const struct attribute_spec c_common_attribute_table[] =
 555 {
 556   /* { name, min_len, max_len, decl_req, type_req, fn_type_req, handler } */
 557   { "packed",                 0, 0, false, false, false,
 558                               handle_packed_attribute },
 559   { "nocommon",               0, 0, true,  false, false,
 560                               handle_nocommon_attribute },
 561   { "common",                 0, 0, true,  false, false,
 562                               handle_common_attribute },
 563   /* FIXME: logically, noreturn attributes should be listed as
 564      "false, true, true" and apply to function types.  But implementing this
 565      would require all the places in the compiler that use TREE_THIS_VOLATILE
 566      on a decl to identify non-returning functions to be located and fixed
 567      to check the function type instead.  */
 568   { "noreturn",               0, 0, true,  false, false,
 569                               handle_noreturn_attribute },
 570   { "volatile",               0, 0, true,  false, false,
 571                               handle_noreturn_attribute },
 572   { "noinline",               0, 0, true,  false, false,
 573                               handle_noinline_attribute },
 574   { "always_inline",          0, 0, true,  false, false,
 575                               handle_always_inline_attribute },
 576   { "flatten",                0, 0, true,  false, false,
 577                               handle_flatten_attribute },
 578   { "used",                   0, 0, true,  false, false,
 579                               handle_used_attribute },
 580   { "unused",                 0, 0, false, false, false,
 581                               handle_unused_attribute },
 582   { "externally_visible",     0, 0, true,  false, false,
 583                               handle_externally_visible_attribute },
 584   /* The same comments as for noreturn attributes apply to const ones.  */
 585   { "const",                  0, 0, true,  false, false,
 586                               handle_const_attribute },
 587   { "transparent_union",      0, 0, false, false, false,
 588                               handle_transparent_union_attribute },
 589   { "constructor",            0, 0, true,  false, false,
 590                               handle_constructor_attribute },
 591   { "destructor",             0, 0, true,  false, false,
 592                               handle_destructor_attribute },
 593   { "mode",                   1, 1, false,  true, false,
 594                               handle_mode_attribute },
 595   { "section",                1, 1, true,  false, false,
 596                               handle_section_attribute },
 597   { "aligned",                0, 1, false, false, false,
 598                               handle_aligned_attribute },
 599   { "weak",                   0, 0, true,  false, false,
 600                               handle_weak_attribute },
 601   { "alias",                  1, 1, true,  false, false,
 602                               handle_alias_attribute },
 603   { "weakref",                0, 1, true,  false, false,
 604                               handle_weakref_attribute },
 605   { "no_instrument_function", 0, 0, true,  false, false,
 606                               handle_no_instrument_function_attribute },
 607   { "malloc",                 0, 0, true,  false, false,
 608                               handle_malloc_attribute },
 609   { "returns_twice",          0, 0, true,  false, false,
 610                               handle_returns_twice_attribute },
 611   { "no_stack_limit",         0, 0, true,  false, false,
 612                               handle_no_limit_stack_attribute },
 613   { "pure",                   0, 0, true,  false, false,
 614                               handle_pure_attribute },
 615   /* For internal use (marking of builtins) only.  The name contains space
 616      to prevent its usage in source code.  */
 617   { "no vops",                0, 0, true,  false, false,
 618                               handle_novops_attribute },
 619   { "deprecated",             0, 0, false, false, false,
 620                               handle_deprecated_attribute },
 621   { "vector_size",            1, 1, false, true, false,
 622                               handle_vector_size_attribute },
 623   { "visibility",             1, 1, false, false, false,
 624                               handle_visibility_attribute },
 625   { "tls_model",              1, 1, true,  false, false,
 626                               handle_tls_model_attribute },
 627   { "nonnull",                0, -1, false, true, true,
 628                               handle_nonnull_attribute },
 629   { "nothrow",                0, 0, true,  false, false,
 630                               handle_nothrow_attribute },
 631   { "may_alias",              0, 0, false, true, false, NULL },
 632   { "cleanup",                1, 1, true, false, false,
 633                               handle_cleanup_attribute },
 634   { "warn_unused_result",     0, 0, false, true, true,
 635                               handle_warn_unused_result_attribute },
 636   { "sentinel",               0, 1, false, true, true,
 637                               handle_sentinel_attribute },
 638   { NULL,                     0, 0, false, false, false, NULL }
 639 };
 640
 641 /* Give the specifications for the format attributes, used by C and all
 642    descendants.  */
 643
 644 const struct attribute_spec c_common_format_attribute_table[] =
 645 {
 646   /* { name, min_len, max_len, decl_req, type_req, fn_type_req, handler } */
 647   { "format",                 3, 3, false, true,  true,
 648                               handle_format_attribute },
 649   { "format_arg",             1, 1, false, true,  true,
 650                               handle_format_arg_attribute },
 651   { NULL,                     0, 0, false, false, false, NULL }
 652 };
 653
 654 /* Push current bindings for the function name VAR_DECLS.  */
 655
 656 void
 657 start_fname_decls (void)
 658 {
 659   unsigned ix;
 660   tree saved = NULL_TREE;
 661
 662   for (ix = 0; fname_vars[ix].decl; ix++)
 663     {
 664       tree decl = *fname_vars[ix].decl;
 665
 666       if (decl)
 667         {
 668           saved = tree_cons (decl, build_int_cst (NULL_TREE, ix), saved);
 669           *fname_vars[ix].decl = NULL_TREE;
 670         }
 671     }
 672   if (saved || saved_function_name_decls)
 673     /* Normally they'll have been NULL, so only push if we've got a
 674        stack, or they are non-NULL.  */
 675     saved_function_name_decls = tree_cons (saved, NULL_TREE,
 676                                            saved_function_name_decls);
 677 }
 678
 679 /* Finish up the current bindings, adding them into the current function's
 680    statement tree.  This must be done _before_ finish_stmt_tree is called.
 681    If there is no current function, we must be at file scope and no statements
 682    are involved. Pop the previous bindings.  */
 683
 684 void
 685 finish_fname_decls (void)
 686 {
 687   unsigned ix;
 688   tree stmts = NULL_TREE;
 689   tree stack = saved_function_name_decls;
 690
 691   for (; stack && TREE_VALUE (stack); stack = TREE_CHAIN (stack))
 692     append_to_statement_list (TREE_VALUE (stack), &stmts);
 693
 694   if (stmts)
 695     {
 696       tree *bodyp = &DECL_SAVED_TREE (current_function_decl);
 697
 698       if (TREE_CODE (*bodyp) == BIND_EXPR)
 699         bodyp = &BIND_EXPR_BODY (*bodyp);
 700
 701       append_to_statement_list_force (*bodyp, &stmts);
 702       *bodyp = stmts;
 703     }
 704
 705   for (ix = 0; fname_vars[ix].decl; ix++)
 706     *fname_vars[ix].decl = NULL_TREE;
 707
 708   if (stack)
 709     {
 710       /* We had saved values, restore them.  */
 711       tree saved;
 712
 713       for (saved = TREE_PURPOSE (stack); saved; saved = TREE_CHAIN (saved))
 714         {
 715           tree decl = TREE_PURPOSE (saved);
 716           unsigned ix = TREE_INT_CST_LOW (TREE_VALUE (saved));
 717
 718           *fname_vars[ix].decl = decl;
 719         }
 720       stack = TREE_CHAIN (stack);
 721     }
 722   saved_function_name_decls = stack;
 723 }
 724
 725 /* Return the text name of the current function, suitably prettified
 726    by PRETTY_P.  Return string must be freed by caller.  */
 727
 728 const char *
 729 fname_as_string (int pretty_p)
 730 {
 731   const char *name = "top level";
 732   char *namep;
 733   int vrb = 2;
 734
 735   if (!pretty_p)
 736     {
 737       name = "";
 738       vrb = 0;
 739     }
 740
 741   if (current_function_decl)
 742     name = lang_hooks.decl_printable_name (current_function_decl, vrb);
 743
 744   if (c_lex_string_translate)
 745     {
 746       int len = strlen (name) + 3; /* Two for '"'s.  One for NULL.  */
 747       cpp_string cstr = { 0, 0 }, strname;
 748
 749       namep = XNEWVEC (char, len);
 750       snprintf (namep, len, "\"%s\"", name);
 751       strname.text = (unsigned char *) namep;
 752       strname.len = len - 1;
 753
 754       if (cpp_interpret_string (parse_in, &strname, 1, &cstr, false))
 755         {
 756           XDELETEVEC (namep);
 757           return (char *) cstr.text;
 758         }
 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 ("%qD is not defined outside of function scope", 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   int length = TREE_STRING_LENGTH (value);
 844   int nchars;
 845   tree e_type, i_type, a_type;
 846
 847   /* Compute the number of elements, for the array type.  */
 848   nchars = wide_flag ? length / wchar_bytes : length;
 849
 850   /* C89 2.2.4.1, C99 5.2.4.1 (Translation limits).  The analogous
 851      limit in C++98 Annex B is very large (65536) and is not normative,
 852      so we do not diagnose it (warn_overlength_strings is forced off
 853      in c_common_post_options).  */
 854   if (warn_overlength_strings)
 855     {
 856       const int nchars_max = flag_isoc99 ? 4095 : 509;
 857       const int relevant_std = flag_isoc99 ? 99 : 90;
 858       if (nchars - 1 > nchars_max)
 859         /* Translators: The %d after 'ISO C' will be 90 or 99.  Do not
 860            separate the %d from the 'C'.  'ISO' should not be
 861            translated, but it may be moved after 'C%d' in languages
 862            where modifiers follow nouns.  */
 863         pedwarn ("string length %qd is greater than the length %qd "
 864                  "ISO C%d compilers are required to support",
 865                  nchars - 1, nchars_max, relevant_std);
 866     }
 867
 868   /* Create the array type for the string constant.  The ISO C++
 869      standard says that a string literal has type `const char[N]' or
 870      `const wchar_t[N]'.  We use the same logic when invoked as a C
 871      front-end with -Wwrite-strings.
 872      ??? We should change the type of an expression depending on the
 873      state of a warning flag.  We should just be warning -- see how
 874      this is handled in the C++ front-end for the deprecated implicit
 875      conversion from string literals to `char*' or `wchar_t*'.
 876
 877      The C++ front end relies on TYPE_MAIN_VARIANT of a cv-qualified
 878      array type being the unqualified version of that type.
 879      Therefore, if we are constructing an array of const char, we must
 880      construct the matching unqualified array type first.  The C front
 881      end does not require this, but it does no harm, so we do it
 882      unconditionally.  */
 883   e_type = wide_flag ? wchar_type_node : char_type_node;
 884   i_type = build_index_type (build_int_cst (NULL_TREE, nchars - 1));
 885   a_type = build_array_type (e_type, i_type);
 886   if (c_dialect_cxx() || warn_write_strings)
 887     a_type = c_build_qualified_type (a_type, TYPE_QUAL_CONST);
 888
 889   TREE_TYPE (value) = a_type;
 890   TREE_CONSTANT (value) = 1;
 891   TREE_INVARIANT (value) = 1;
 892   TREE_READONLY (value) = 1;
 893   TREE_STATIC (value) = 1;
 894   return value;
 895 }
 896 \f
 897 /* Print a warning if a constant expression had overflow in folding.
 898    Invoke this function on every expression that the language
 899    requires to be a constant expression.
 900    Note the ANSI C standard says it is erroneous for a
 901    constant expression to overflow.  */
 902
 903 void
 904 constant_expression_warning (tree value)
 905 {
 906   if ((TREE_CODE (value) == INTEGER_CST || TREE_CODE (value) == REAL_CST
 907        || TREE_CODE (value) == VECTOR_CST
 908        || TREE_CODE (value) == COMPLEX_CST)
 909       && TREE_CONSTANT_OVERFLOW (value)
 910       && warn_overflow
 911       && pedantic)
 912     pedwarn ("overflow in constant expression");
 913 }
 914
 915 /* Print a warning if an expression had overflow in folding.
 916    Invoke this function on every expression that
 917    (1) appears in the source code, and
 918    (2) might be a constant expression that overflowed, and
 919    (3) is not already checked by convert_and_check;
 920    however, do not invoke this function on operands of explicit casts.  */
 921
 922 void
 923 overflow_warning (tree value)
 924 {
 925   if ((TREE_CODE (value) == INTEGER_CST
 926        || (TREE_CODE (value) == COMPLEX_CST
 927            && TREE_CODE (TREE_REALPART (value)) == INTEGER_CST))
 928       && TREE_OVERFLOW (value))
 929     {
 930       TREE_OVERFLOW (value) = 0;
 931       if (skip_evaluation == 0)
 932         warning (OPT_Woverflow, "integer overflow in expression");
 933     }
 934   else if ((TREE_CODE (value) == REAL_CST
 935             || (TREE_CODE (value) == COMPLEX_CST
 936                 && TREE_CODE (TREE_REALPART (value)) == REAL_CST))
 937            && TREE_OVERFLOW (value))
 938     {
 939       TREE_OVERFLOW (value) = 0;
 940       if (skip_evaluation == 0)
 941         warning (OPT_Woverflow, "floating point overflow in expression");
 942     }
 943   else if (TREE_CODE (value) == VECTOR_CST && TREE_OVERFLOW (value))
 944     {
 945       TREE_OVERFLOW (value) = 0;
 946       if (skip_evaluation == 0)
 947         warning (OPT_Woverflow, "vector overflow in expression");
 948     }
 949 }
 950
 951 /* Print a warning if a large constant is truncated to unsigned,
 952    or if -Wconversion is used and a constant < 0 is converted to unsigned.
 953    Invoke this function on every expression that might be implicitly
 954    converted to an unsigned type.  */
 955
 956 static void
 957 unsigned_conversion_warning (tree result, tree operand)
 958 {
 959   tree type = TREE_TYPE (result);
 960
 961   if (TREE_CODE (operand) == INTEGER_CST
 962       && TREE_CODE (type) == INTEGER_TYPE
 963       && TYPE_UNSIGNED (type)
 964       && skip_evaluation == 0
 965       && !int_fits_type_p (operand, type))
 966     {
 967       if (!int_fits_type_p (operand, c_common_signed_type (type)))
 968         /* This detects cases like converting -129 or 256 to unsigned char.  */
 969         warning (OPT_Woverflow,
 970                  "large integer implicitly truncated to unsigned type");
 971       else
 972         warning (OPT_Wconversion,
 973                  "negative integer implicitly converted to unsigned type");
 974     }
 975 }
 976
 977 /* Print a warning about casts that might indicate violation
 978    of strict aliasing rules if -Wstrict-aliasing is used and
 979    strict aliasing mode is in effect. OTYPE is the original
 980    TREE_TYPE of EXPR, and TYPE the type we're casting to. */
 981
 982 void
 983 strict_aliasing_warning (tree otype, tree type, tree expr)
 984 {
 985   if (flag_strict_aliasing && warn_strict_aliasing
 986       && POINTER_TYPE_P (type) && POINTER_TYPE_P (otype)
 987       && TREE_CODE (expr) == ADDR_EXPR
 988       && (DECL_P (TREE_OPERAND (expr, 0))
 989           || handled_component_p (TREE_OPERAND (expr, 0)))
 990       && !VOID_TYPE_P (TREE_TYPE (type)))
 991     {
 992       /* Casting the address of an object to non void pointer. Warn
 993          if the cast breaks type based aliasing.  */
 994       if (!COMPLETE_TYPE_P (TREE_TYPE (type)))
 995         warning (OPT_Wstrict_aliasing, "type-punning to incomplete type "
 996                  "might break strict-aliasing rules");
 997       else
 998         {
 999           HOST_WIDE_INT set1 = get_alias_set (TREE_TYPE (TREE_OPERAND (expr, 0)));
1000           HOST_WIDE_INT set2 = get_alias_set (TREE_TYPE (type));
1001
1002           if (!alias_sets_conflict_p (set1, set2))
1003             warning (OPT_Wstrict_aliasing, "dereferencing type-punned "
1004                      "pointer will break strict-aliasing rules");
1005           else if (warn_strict_aliasing > 1
1006                   && !alias_sets_might_conflict_p (set1, set2))
1007             warning (OPT_Wstrict_aliasing, "dereferencing type-punned "
1008                      "pointer might break strict-aliasing rules");
1009         }
1010     }
1011 }
1012
1013
1014 /* Print a warning about if (); or if () .. else; constructs
1015    via the special empty statement node that we create.  INNER_THEN
1016    and INNER_ELSE are the statement lists of the if and the else
1017    block.  */
1018
1019 void
1020 empty_body_warning (tree inner_then, tree inner_else)
1021 {
1022   if (extra_warnings)
1023     {
1024       if (TREE_CODE (inner_then) == STATEMENT_LIST
1025           && STATEMENT_LIST_TAIL (inner_then))
1026         inner_then = STATEMENT_LIST_TAIL (inner_then)->stmt;
1027
1028       if (inner_else && TREE_CODE (inner_else) == STATEMENT_LIST
1029           && STATEMENT_LIST_TAIL (inner_else))
1030         inner_else = STATEMENT_LIST_TAIL (inner_else)->stmt;
1031
1032       if (IS_EMPTY_STMT (inner_then) && !inner_else)
1033         warning (OPT_Wextra, "%Hempty body in an if-statement",
1034                  EXPR_LOCUS (inner_then));
1035
1036       if (inner_else && IS_EMPTY_STMT (inner_else))
1037         warning (OPT_Wextra, "%Hempty body in an else-statement",
1038                  EXPR_LOCUS (inner_else));
1039    }
1040 }
1041
1042
1043 /* Nonzero if constant C has a value that is permissible
1044    for type TYPE (an INTEGER_TYPE).  */
1045
1046 static int
1047 constant_fits_type_p (tree c, tree type)
1048 {
1049   if (TREE_CODE (c) == INTEGER_CST)
1050     return int_fits_type_p (c, type);
1051
1052   c = convert (type, c);
1053   return !TREE_OVERFLOW (c);
1054 }
1055
1056 /* Nonzero if vector types T1 and T2 can be converted to each other
1057    without an explicit cast.  */
1058 int
1059 vector_types_convertible_p (tree t1, tree t2)
1060 {
1061   return targetm.vector_opaque_p (t1)
1062          || targetm.vector_opaque_p (t2)
1063          || (tree_int_cst_equal (TYPE_SIZE (t1), TYPE_SIZE (t2))
1064              && (TREE_CODE (TREE_TYPE (t1)) != REAL_TYPE ||
1065                  TYPE_PRECISION (t1) == TYPE_PRECISION (t2))
1066              && INTEGRAL_TYPE_P (TREE_TYPE (t1))
1067                 == INTEGRAL_TYPE_P (TREE_TYPE (t2)));
1068 }
1069
1070 /* Convert EXPR to TYPE, warning about conversion problems with constants.
1071    Invoke this function on every expression that is converted implicitly,
1072    i.e. because of language rules and not because of an explicit cast.  */
1073
1074 tree
1075 convert_and_check (tree type, tree expr)
1076 {
1077   tree t = convert (type, expr);
1078   if (TREE_CODE (t) == INTEGER_CST)
1079     {
1080       if (TREE_OVERFLOW (t))
1081         {
1082           TREE_OVERFLOW (t) = 0;
1083
1084           /* Do not diagnose overflow in a constant expression merely
1085              because a conversion overflowed.  */
1086           TREE_CONSTANT_OVERFLOW (t) = CONSTANT_CLASS_P (expr)
1087                                        && TREE_CONSTANT_OVERFLOW (expr);
1088
1089           /* No warning for converting 0x80000000 to int.  */
1090           if (!(TYPE_UNSIGNED (type) < TYPE_UNSIGNED (TREE_TYPE (expr))
1091                 && TREE_CODE (TREE_TYPE (expr)) == INTEGER_TYPE
1092                 && TYPE_PRECISION (type) == TYPE_PRECISION (TREE_TYPE (expr))))
1093             /* If EXPR fits in the unsigned version of TYPE,
1094                don't warn unless pedantic.  */
1095             if ((pedantic
1096                  || TYPE_UNSIGNED (type)
1097                  || !constant_fits_type_p (expr,
1098                                            c_common_unsigned_type (type)))
1099                 && skip_evaluation == 0)
1100               warning (OPT_Woverflow,
1101                        "overflow in implicit constant conversion");
1102         }
1103       else
1104         unsigned_conversion_warning (t, expr);
1105     }
1106   return t;
1107 }
1108 \f
1109 /* A node in a list that describes references to variables (EXPR), which are
1110    either read accesses if WRITER is zero, or write accesses, in which case
1111    WRITER is the parent of EXPR.  */
1112 struct tlist
1113 {
1114   struct tlist *next;
1115   tree expr, writer;
1116 };
1117
1118 /* Used to implement a cache the results of a call to verify_tree.  We only
1119    use this for SAVE_EXPRs.  */
1120 struct tlist_cache
1121 {
1122   struct tlist_cache *next;
1123   struct tlist *cache_before_sp;
1124   struct tlist *cache_after_sp;
1125   tree expr;
1126 };
1127
1128 /* Obstack to use when allocating tlist structures, and corresponding
1129    firstobj.  */
1130 static struct obstack tlist_obstack;
1131 static char *tlist_firstobj = 0;
1132
1133 /* Keep track of the identifiers we've warned about, so we can avoid duplicate
1134    warnings.  */
1135 static struct tlist *warned_ids;
1136 /* SAVE_EXPRs need special treatment.  We process them only once and then
1137    cache the results.  */
1138 static struct tlist_cache *save_expr_cache;
1139
1140 static void add_tlist (struct tlist **, struct tlist *, tree, int);
1141 static void merge_tlist (struct tlist **, struct tlist *, int);
1142 static void verify_tree (tree, struct tlist **, struct tlist **, tree);
1143 static int warning_candidate_p (tree);
1144 static void warn_for_collisions (struct tlist *);
1145 static void warn_for_collisions_1 (tree, tree, struct tlist *, int);
1146 static struct tlist *new_tlist (struct tlist *, tree, tree);
1147
1148 /* Create a new struct tlist and fill in its fields.  */
1149 static struct tlist *
1150 new_tlist (struct tlist *next, tree t, tree writer)
1151 {
1152   struct tlist *l;
1153   l = XOBNEW (&tlist_obstack, struct tlist);
1154   l->next = next;
1155   l->expr = t;
1156   l->writer = writer;
1157   return l;
1158 }
1159
1160 /* Add duplicates of the nodes found in ADD to the list *TO.  If EXCLUDE_WRITER
1161    is nonnull, we ignore any node we find which has a writer equal to it.  */
1162
1163 static void
1164 add_tlist (struct tlist **to, struct tlist *add, tree exclude_writer, int copy)
1165 {
1166   while (add)
1167     {
1168       struct tlist *next = add->next;
1169       if (!copy)
1170         add->next = *to;
1171       if (!exclude_writer || add->writer != exclude_writer)
1172         *to = copy ? new_tlist (*to, add->expr, add->writer) : add;
1173       add = next;
1174     }
1175 }
1176
1177 /* Merge the nodes of ADD into TO.  This merging process is done so that for
1178    each variable that already exists in TO, no new node is added; however if
1179    there is a write access recorded in ADD, and an occurrence on TO is only
1180    a read access, then the occurrence in TO will be modified to record the
1181    write.  */
1182
1183 static void
1184 merge_tlist (struct tlist **to, struct tlist *add, int copy)
1185 {
1186   struct tlist **end = to;
1187
1188   while (*end)
1189     end = &(*end)->next;
1190
1191   while (add)
1192     {
1193       int found = 0;
1194       struct tlist *tmp2;
1195       struct tlist *next = add->next;
1196
1197       for (tmp2 = *to; tmp2; tmp2 = tmp2->next)
1198         if (tmp2->expr == add->expr)
1199           {
1200             found = 1;
1201             if (!tmp2->writer)
1202               tmp2->writer = add->writer;
1203           }
1204       if (!found)
1205         {
1206           *end = copy ? add : new_tlist (NULL, add->expr, add->writer);
1207           end = &(*end)->next;
1208           *end = 0;
1209         }
1210       add = next;
1211     }
1212 }
1213
1214 /* WRITTEN is a variable, WRITER is its parent.  Warn if any of the variable
1215    references in list LIST conflict with it, excluding reads if ONLY writers
1216    is nonzero.  */
1217
1218 static void
1219 warn_for_collisions_1 (tree written, tree writer, struct tlist *list,
1220                        int only_writes)
1221 {
1222   struct tlist *tmp;
1223
1224   /* Avoid duplicate warnings.  */
1225   for (tmp = warned_ids; tmp; tmp = tmp->next)
1226     if (tmp->expr == written)
1227       return;
1228
1229   while (list)
1230     {
1231       if (list->expr == written
1232           && list->writer != writer
1233           && (!only_writes || list->writer)
1234           && DECL_NAME (list->expr))
1235         {
1236           warned_ids = new_tlist (warned_ids, written, NULL_TREE);
1237           warning (0, "operation on %qE may be undefined", list->expr);
1238         }
1239       list = list->next;
1240     }
1241 }
1242
1243 /* Given a list LIST of references to variables, find whether any of these
1244    can cause conflicts due to missing sequence points.  */
1245
1246 static void
1247 warn_for_collisions (struct tlist *list)
1248 {
1249   struct tlist *tmp;
1250
1251   for (tmp = list; tmp; tmp = tmp->next)
1252     {
1253       if (tmp->writer)
1254         warn_for_collisions_1 (tmp->expr, tmp->writer, list, 0);
1255     }
1256 }
1257
1258 /* Return nonzero if X is a tree that can be verified by the sequence point
1259    warnings.  */
1260 static int
1261 warning_candidate_p (tree x)
1262 {
1263   return TREE_CODE (x) == VAR_DECL || TREE_CODE (x) == PARM_DECL;
1264 }
1265
1266 /* Walk the tree X, and record accesses to variables.  If X is written by the
1267    parent tree, WRITER is the parent.
1268    We store accesses in one of the two lists: PBEFORE_SP, and PNO_SP.  If this
1269    expression or its only operand forces a sequence point, then everything up
1270    to the sequence point is stored in PBEFORE_SP.  Everything else gets stored
1271    in PNO_SP.
1272    Once we return, we will have emitted warnings if any subexpression before
1273    such a sequence point could be undefined.  On a higher level, however, the
1274    sequence point may not be relevant, and we'll merge the two lists.
1275
1276    Example: (b++, a) + b;
1277    The call that processes the COMPOUND_EXPR will store the increment of B
1278    in PBEFORE_SP, and the use of A in PNO_SP.  The higher-level call that
1279    processes the PLUS_EXPR will need to merge the two lists so that
1280    eventually, all accesses end up on the same list (and we'll warn about the
1281    unordered subexpressions b++ and b.
1282
1283    A note on merging.  If we modify the former example so that our expression
1284    becomes
1285      (b++, b) + a
1286    care must be taken not simply to add all three expressions into the final
1287    PNO_SP list.  The function merge_tlist takes care of that by merging the
1288    before-SP list of the COMPOUND_EXPR into its after-SP list in a special
1289    way, so that no more than one access to B is recorded.  */
1290
1291 static void
1292 verify_tree (tree x, struct tlist **pbefore_sp, struct tlist **pno_sp,
1293              tree writer)
1294 {
1295   struct tlist *tmp_before, *tmp_nosp, *tmp_list2, *tmp_list3;
1296   enum tree_code code;
1297   enum tree_code_class cl;
1298
1299   /* X may be NULL if it is the operand of an empty statement expression
1300      ({ }).  */
1301   if (x == NULL)
1302     return;
1303
1304  restart:
1305   code = TREE_CODE (x);
1306   cl = TREE_CODE_CLASS (code);
1307
1308   if (warning_candidate_p (x))
1309     {
1310       *pno_sp = new_tlist (*pno_sp, x, writer);
1311       return;
1312     }
1313
1314   switch (code)
1315     {
1316     case CONSTRUCTOR:
1317       return;
1318
1319     case COMPOUND_EXPR:
1320     case TRUTH_ANDIF_EXPR:
1321     case TRUTH_ORIF_EXPR:
1322       tmp_before = tmp_nosp = tmp_list3 = 0;
1323       verify_tree (TREE_OPERAND (x, 0), &tmp_before, &tmp_nosp, NULL_TREE);
1324       warn_for_collisions (tmp_nosp);
1325       merge_tlist (pbefore_sp, tmp_before, 0);
1326       merge_tlist (pbefore_sp, tmp_nosp, 0);
1327       verify_tree (TREE_OPERAND (x, 1), &tmp_list3, pno_sp, NULL_TREE);
1328       merge_tlist (pbefore_sp, tmp_list3, 0);
1329       return;
1330
1331     case COND_EXPR:
1332       tmp_before = tmp_list2 = 0;
1333       verify_tree (TREE_OPERAND (x, 0), &tmp_before, &tmp_list2, NULL_TREE);
1334       warn_for_collisions (tmp_list2);
1335       merge_tlist (pbefore_sp, tmp_before, 0);
1336       merge_tlist (pbefore_sp, tmp_list2, 1);
1337
1338       tmp_list3 = tmp_nosp = 0;
1339       verify_tree (TREE_OPERAND (x, 1), &tmp_list3, &tmp_nosp, NULL_TREE);
1340       warn_for_collisions (tmp_nosp);
1341       merge_tlist (pbefore_sp, tmp_list3, 0);
1342
1343       tmp_list3 = tmp_list2 = 0;
1344       verify_tree (TREE_OPERAND (x, 2), &tmp_list3, &tmp_list2, NULL_TREE);
1345       warn_for_collisions (tmp_list2);
1346       merge_tlist (pbefore_sp, tmp_list3, 0);
1347       /* Rather than add both tmp_nosp and tmp_list2, we have to merge the
1348          two first, to avoid warning for (a ? b++ : b++).  */
1349       merge_tlist (&tmp_nosp, tmp_list2, 0);
1350       add_tlist (pno_sp, tmp_nosp, NULL_TREE, 0);
1351       return;
1352
1353     case PREDECREMENT_EXPR:
1354     case PREINCREMENT_EXPR:
1355     case POSTDECREMENT_EXPR:
1356     case POSTINCREMENT_EXPR:
1357       verify_tree (TREE_OPERAND (x, 0), pno_sp, pno_sp, x);
1358       return;
1359
1360     case MODIFY_EXPR:
1361       tmp_before = tmp_nosp = tmp_list3 = 0;
1362       verify_tree (TREE_OPERAND (x, 1), &tmp_before, &tmp_nosp, NULL_TREE);
1363       verify_tree (TREE_OPERAND (x, 0), &tmp_list3, &tmp_list3, x);
1364       /* Expressions inside the LHS are not ordered wrt. the sequence points
1365          in the RHS.  Example:
1366            *a = (a++, 2)
1367          Despite the fact that the modification of "a" is in the before_sp
1368          list (tmp_before), it conflicts with the use of "a" in the LHS.
1369          We can handle this by adding the contents of tmp_list3
1370          to those of tmp_before, and redoing the collision warnings for that
1371          list.  */
1372       add_tlist (&tmp_before, tmp_list3, x, 1);
1373       warn_for_collisions (tmp_before);
1374       /* Exclude the LHS itself here; we first have to merge it into the
1375          tmp_nosp list.  This is done to avoid warning for "a = a"; if we
1376          didn't exclude the LHS, we'd get it twice, once as a read and once
1377          as a write.  */
1378       add_tlist (pno_sp, tmp_list3, x, 0);
1379       warn_for_collisions_1 (TREE_OPERAND (x, 0), x, tmp_nosp, 1);
1380
1381       merge_tlist (pbefore_sp, tmp_before, 0);
1382       if (warning_candidate_p (TREE_OPERAND (x, 0)))
1383         merge_tlist (&tmp_nosp, new_tlist (NULL, TREE_OPERAND (x, 0), x), 0);
1384       add_tlist (pno_sp, tmp_nosp, NULL_TREE, 1);
1385       return;
1386
1387     case CALL_EXPR:
1388       /* We need to warn about conflicts among arguments and conflicts between
1389          args and the function address.  Side effects of the function address,
1390          however, are not ordered by the sequence point of the call.  */
1391       tmp_before = tmp_nosp = tmp_list2 = tmp_list3 = 0;
1392       verify_tree (TREE_OPERAND (x, 0), &tmp_before, &tmp_nosp, NULL_TREE);
1393       if (TREE_OPERAND (x, 1))
1394         verify_tree (TREE_OPERAND (x, 1), &tmp_list2, &tmp_list3, NULL_TREE);
1395       merge_tlist (&tmp_list3, tmp_list2, 0);
1396       add_tlist (&tmp_before, tmp_list3, NULL_TREE, 0);
1397       add_tlist (&tmp_before, tmp_nosp, NULL_TREE, 0);
1398       warn_for_collisions (tmp_before);
1399       add_tlist (pbefore_sp, tmp_before, NULL_TREE, 0);
1400       return;
1401
1402     case TREE_LIST:
1403       /* Scan all the list, e.g. indices of multi dimensional array.  */
1404       while (x)
1405         {
1406           tmp_before = tmp_nosp = 0;
1407           verify_tree (TREE_VALUE (x), &tmp_before, &tmp_nosp, NULL_TREE);
1408           merge_tlist (&tmp_nosp, tmp_before, 0);
1409           add_tlist (pno_sp, tmp_nosp, NULL_TREE, 0);
1410           x = TREE_CHAIN (x);
1411         }
1412       return;
1413
1414     case SAVE_EXPR:
1415       {
1416         struct tlist_cache *t;
1417         for (t = save_expr_cache; t; t = t->next)
1418           if (t->expr == x)
1419             break;
1420
1421         if (!t)
1422           {
1423             t = XOBNEW (&tlist_obstack, struct tlist_cache);
1424             t->next = save_expr_cache;
1425             t->expr = x;
1426             save_expr_cache = t;
1427
1428             tmp_before = tmp_nosp = 0;
1429             verify_tree (TREE_OPERAND (x, 0), &tmp_before, &tmp_nosp, NULL_TREE);
1430             warn_for_collisions (tmp_nosp);
1431
1432             tmp_list3 = 0;
1433             while (tmp_nosp)
1434               {
1435                 struct tlist *t = tmp_nosp;
1436                 tmp_nosp = t->next;
1437                 merge_tlist (&tmp_list3, t, 0);
1438               }
1439             t->cache_before_sp = tmp_before;
1440             t->cache_after_sp = tmp_list3;
1441           }
1442         merge_tlist (pbefore_sp, t->cache_before_sp, 1);
1443         add_tlist (pno_sp, t->cache_after_sp, NULL_TREE, 1);
1444         return;
1445       }
1446
1447     default:
1448       /* For other expressions, simply recurse on their operands.
1449          Manual tail recursion for unary expressions.
1450          Other non-expressions need not be processed.  */
1451       if (cl == tcc_unary)
1452         {
1453           x = TREE_OPERAND (x, 0);
1454           writer = 0;
1455           goto restart;
1456         }
1457       else if (IS_EXPR_CODE_CLASS (cl))
1458         {
1459           int lp;
1460           int max = TREE_CODE_LENGTH (TREE_CODE (x));
1461           for (lp = 0; lp < max; lp++)
1462             {
1463               tmp_before = tmp_nosp = 0;
1464               verify_tree (TREE_OPERAND (x, lp), &tmp_before, &tmp_nosp, 0);
1465               merge_tlist (&tmp_nosp, tmp_before, 0);
1466               add_tlist (pno_sp, tmp_nosp, NULL_TREE, 0);
1467             }
1468         }
1469       return;
1470     }
1471 }
1472
1473 /* Try to warn for undefined behavior in EXPR due to missing sequence
1474    points.  */
1475
1476 void
1477 verify_sequence_points (tree expr)
1478 {
1479   struct tlist *before_sp = 0, *after_sp = 0;
1480
1481   warned_ids = 0;
1482   save_expr_cache = 0;
1483   if (tlist_firstobj == 0)
1484     {
1485       gcc_obstack_init (&tlist_obstack);
1486       tlist_firstobj = (char *) obstack_alloc (&tlist_obstack, 0);
1487     }
1488
1489   verify_tree (expr, &before_sp, &after_sp, 0);
1490   warn_for_collisions (after_sp);
1491   obstack_free (&tlist_obstack, tlist_firstobj);
1492 }
1493 \f
1494 /* Validate the expression after `case' and apply default promotions.  */
1495
1496 static tree
1497 check_case_value (tree value)
1498 {
1499   if (value == NULL_TREE)
1500     return value;
1501
1502   /* ??? Can we ever get nops here for a valid case value?  We
1503      shouldn't for C.  */
1504   STRIP_TYPE_NOPS (value);
1505   /* In C++, the following is allowed:
1506
1507        const int i = 3;
1508        switch (...) { case i: ... }
1509
1510      So, we try to reduce the VALUE to a constant that way.  */
1511   if (c_dialect_cxx ())
1512     {
1513       value = decl_constant_value (value);
1514       STRIP_TYPE_NOPS (value);
1515       value = fold (value);
1516     }
1517
1518   if (TREE_CODE (value) == INTEGER_CST)
1519     /* Promote char or short to int.  */
1520     value = perform_integral_promotions (value);
1521   else if (value != error_mark_node)
1522     {
1523       error ("case label does not reduce to an integer constant");
1524       value = error_mark_node;
1525     }
1526
1527   constant_expression_warning (value);
1528
1529   return value;
1530 }
1531 \f
1532 /* See if the case values LOW and HIGH are in the range of the original
1533    type (i.e. before the default conversion to int) of the switch testing
1534    expression.
1535    TYPE is the promoted type of the testing expression, and ORIG_TYPE is
1536    the type before promoting it.  CASE_LOW_P is a pointer to the lower
1537    bound of the case label, and CASE_HIGH_P is the upper bound or NULL
1538    if the case is not a case range.
1539    The caller has to make sure that we are not called with NULL for
1540    CASE_LOW_P (i.e. the default case).
1541    Returns true if the case label is in range of ORIG_TYPE (saturated or
1542    untouched) or false if the label is out of range.  */
1543
1544 static bool
1545 check_case_bounds (tree type, tree orig_type,
1546                    tree *case_low_p, tree *case_high_p)
1547 {
1548   tree min_value, max_value;
1549   tree case_low = *case_low_p;
1550   tree case_high = case_high_p ? *case_high_p : case_low;
1551
1552   /* If there was a problem with the original type, do nothing.  */
1553   if (orig_type == error_mark_node)
1554     return true;
1555
1556   min_value = TYPE_MIN_VALUE (orig_type);
1557   max_value = TYPE_MAX_VALUE (orig_type);
1558
1559   /* Case label is less than minimum for type.  */
1560   if (tree_int_cst_compare (case_low, min_value) < 0
1561       && tree_int_cst_compare (case_high, min_value) < 0)
1562     {
1563       warning (0, "case label value is less than minimum value for type");
1564       return false;
1565     }
1566
1567   /* Case value is greater than maximum for type.  */
1568   if (tree_int_cst_compare (case_low, max_value) > 0
1569       && tree_int_cst_compare (case_high, max_value) > 0)
1570     {
1571       warning (0, "case label value exceeds maximum value for type");
1572       return false;
1573     }
1574
1575   /* Saturate lower case label value to minimum.  */
1576   if (tree_int_cst_compare (case_high, min_value) >= 0
1577       && tree_int_cst_compare (case_low, min_value) < 0)
1578     {
1579       warning (0, "lower value in case label range"
1580                " less than minimum value for type");
1581       case_low = min_value;
1582     }
1583
1584   /* Saturate upper case label value to maximum.  */
1585   if (tree_int_cst_compare (case_low, max_value) <= 0
1586       && tree_int_cst_compare (case_high, max_value) > 0)
1587     {
1588       warning (0, "upper value in case label range"
1589                " exceeds maximum value for type");
1590       case_high = max_value;
1591     }
1592
1593   if (*case_low_p != case_low)
1594     *case_low_p = convert (type, case_low);
1595   if (case_high_p && *case_high_p != case_high)
1596     *case_high_p = convert (type, case_high);
1597
1598   return true;
1599 }
1600 \f
1601 /* Return an integer type with BITS bits of precision,
1602    that is unsigned if UNSIGNEDP is nonzero, otherwise signed.  */
1603
1604 tree
1605 c_common_type_for_size (unsigned int bits, int unsignedp)
1606 {
1607   if (bits == TYPE_PRECISION (integer_type_node))
1608     return unsignedp ? unsigned_type_node : integer_type_node;
1609
1610   if (bits == TYPE_PRECISION (signed_char_type_node))
1611     return unsignedp ? unsigned_char_type_node : signed_char_type_node;
1612
1613   if (bits == TYPE_PRECISION (short_integer_type_node))
1614     return unsignedp ? short_unsigned_type_node : short_integer_type_node;
1615
1616   if (bits == TYPE_PRECISION (long_integer_type_node))
1617     return unsignedp ? long_unsigned_type_node : long_integer_type_node;
1618
1619   if (bits == TYPE_PRECISION (long_long_integer_type_node))
1620     return (unsignedp ? long_long_unsigned_type_node
1621             : long_long_integer_type_node);
1622
1623   if (bits == TYPE_PRECISION (widest_integer_literal_type_node))
1624     return (unsignedp ? widest_unsigned_literal_type_node
1625             : widest_integer_literal_type_node);
1626
1627   if (bits <= TYPE_PRECISION (intQI_type_node))
1628     return unsignedp ? unsigned_intQI_type_node : intQI_type_node;
1629
1630   if (bits <= TYPE_PRECISION (intHI_type_node))
1631     return unsignedp ? unsigned_intHI_type_node : intHI_type_node;
1632
1633   if (bits <= TYPE_PRECISION (intSI_type_node))
1634     return unsignedp ? unsigned_intSI_type_node : intSI_type_node;
1635
1636   if (bits <= TYPE_PRECISION (intDI_type_node))
1637     return unsignedp ? unsigned_intDI_type_node : intDI_type_node;
1638
1639   return 0;
1640 }
1641
1642 /* Used for communication between c_common_type_for_mode and
1643    c_register_builtin_type.  */
1644 static GTY(()) tree registered_builtin_types;
1645
1646 /* Return a data type that has machine mode MODE.
1647    If the mode is an integer,
1648    then UNSIGNEDP selects between signed and unsigned types.  */
1649
1650 tree
1651 c_common_type_for_mode (enum machine_mode mode, int unsignedp)
1652 {
1653   tree t;
1654
1655   if (mode == TYPE_MODE (integer_type_node))
1656     return unsignedp ? unsigned_type_node : integer_type_node;
1657
1658   if (mode == TYPE_MODE (signed_char_type_node))
1659     return unsignedp ? unsigned_char_type_node : signed_char_type_node;
1660
1661   if (mode == TYPE_MODE (short_integer_type_node))
1662     return unsignedp ? short_unsigned_type_node : short_integer_type_node;
1663
1664   if (mode == TYPE_MODE (long_integer_type_node))
1665     return unsignedp ? long_unsigned_type_node : long_integer_type_node;
1666
1667   if (mode == TYPE_MODE (long_long_integer_type_node))
1668     return unsignedp ? long_long_unsigned_type_node : long_long_integer_type_node;
1669
1670   if (mode == TYPE_MODE (widest_integer_literal_type_node))
1671     return unsignedp ? widest_unsigned_literal_type_node
1672                      : widest_integer_literal_type_node;
1673
1674   if (mode == QImode)
1675     return unsignedp ? unsigned_intQI_type_node : intQI_type_node;
1676
1677   if (mode == HImode)
1678     return unsignedp ? unsigned_intHI_type_node : intHI_type_node;
1679
1680   if (mode == SImode)
1681     return unsignedp ? unsigned_intSI_type_node : intSI_type_node;
1682
1683   if (mode == DImode)
1684     return unsignedp ? unsigned_intDI_type_node : intDI_type_node;
1685
1686 #if HOST_BITS_PER_WIDE_INT >= 64
1687   if (mode == TYPE_MODE (intTI_type_node))
1688     return unsignedp ? unsigned_intTI_type_node : intTI_type_node;
1689 #endif
1690
1691   if (mode == TYPE_MODE (float_type_node))
1692     return float_type_node;
1693
1694   if (mode == TYPE_MODE (double_type_node))
1695     return double_type_node;
1696
1697   if (mode == TYPE_MODE (long_double_type_node))
1698     return long_double_type_node;
1699
1700   if (mode == TYPE_MODE (void_type_node))
1701     return void_type_node;
1702
1703   if (mode == TYPE_MODE (build_pointer_type (char_type_node)))
1704     return (unsignedp
1705             ? make_unsigned_type (GET_MODE_PRECISION (mode))
1706             : make_signed_type (GET_MODE_PRECISION (mode)));
1707
1708   if (mode == TYPE_MODE (build_pointer_type (integer_type_node)))
1709     return (unsignedp
1710             ? make_unsigned_type (GET_MODE_PRECISION (mode))
1711             : make_signed_type (GET_MODE_PRECISION (mode)));
1712
1713   if (COMPLEX_MODE_P (mode))
1714     {
1715       enum machine_mode inner_mode;
1716       tree inner_type;
1717
1718       if (mode == TYPE_MODE (complex_float_type_node))
1719         return complex_float_type_node;
1720       if (mode == TYPE_MODE (complex_double_type_node))
1721         return complex_double_type_node;
1722       if (mode == TYPE_MODE (complex_long_double_type_node))
1723         return complex_long_double_type_node;
1724
1725       if (mode == TYPE_MODE (complex_integer_type_node) && !unsignedp)
1726         return complex_integer_type_node;
1727
1728       inner_mode = GET_MODE_INNER (mode);
1729       inner_type = c_common_type_for_mode (inner_mode, unsignedp);
1730       if (inner_type != NULL_TREE)
1731         return build_complex_type (inner_type);
1732     }
1733   else if (VECTOR_MODE_P (mode))
1734     {
1735       enum machine_mode inner_mode = GET_MODE_INNER (mode);
1736       tree inner_type = c_common_type_for_mode (inner_mode, unsignedp);
1737       if (inner_type != NULL_TREE)
1738         return build_vector_type_for_mode (inner_type, mode);
1739     }
1740
1741   if (mode == TYPE_MODE (dfloat32_type_node))
1742     return dfloat32_type_node;
1743   if (mode == TYPE_MODE (dfloat64_type_node))
1744     return dfloat64_type_node;
1745   if (mode == TYPE_MODE (dfloat128_type_node))
1746     return dfloat128_type_node;
1747
1748   for (t = registered_builtin_types; t; t = TREE_CHAIN (t))
1749     if (TYPE_MODE (TREE_VALUE (t)) == mode)
1750       return TREE_VALUE (t);
1751
1752   return 0;
1753 }
1754
1755 /* Return an unsigned type the same as TYPE in other respects.  */
1756 tree
1757 c_common_unsigned_type (tree type)
1758 {
1759   tree type1 = TYPE_MAIN_VARIANT (type);
1760   if (type1 == signed_char_type_node || type1 == char_type_node)
1761     return unsigned_char_type_node;
1762   if (type1 == integer_type_node)
1763     return unsigned_type_node;
1764   if (type1 == short_integer_type_node)
1765     return short_unsigned_type_node;
1766   if (type1 == long_integer_type_node)
1767     return long_unsigned_type_node;
1768   if (type1 == long_long_integer_type_node)
1769     return long_long_unsigned_type_node;
1770   if (type1 == widest_integer_literal_type_node)
1771     return widest_unsigned_literal_type_node;
1772 #if HOST_BITS_PER_WIDE_INT >= 64
1773   if (type1 == intTI_type_node)
1774     return unsigned_intTI_type_node;
1775 #endif
1776   if (type1 == intDI_type_node)
1777     return unsigned_intDI_type_node;
1778   if (type1 == intSI_type_node)
1779     return unsigned_intSI_type_node;
1780   if (type1 == intHI_type_node)
1781     return unsigned_intHI_type_node;
1782   if (type1 == intQI_type_node)
1783     return unsigned_intQI_type_node;
1784
1785   return c_common_signed_or_unsigned_type (1, type);
1786 }
1787
1788 /* Return a signed type the same as TYPE in other respects.  */
1789
1790 tree
1791 c_common_signed_type (tree type)
1792 {
1793   tree type1 = TYPE_MAIN_VARIANT (type);
1794   if (type1 == unsigned_char_type_node || type1 == char_type_node)
1795     return signed_char_type_node;
1796   if (type1 == unsigned_type_node)
1797     return integer_type_node;
1798   if (type1 == short_unsigned_type_node)
1799     return short_integer_type_node;
1800   if (type1 == long_unsigned_type_node)
1801     return long_integer_type_node;
1802   if (type1 == long_long_unsigned_type_node)
1803     return long_long_integer_type_node;
1804   if (type1 == widest_unsigned_literal_type_node)
1805     return widest_integer_literal_type_node;
1806 #if HOST_BITS_PER_WIDE_INT >= 64
1807   if (type1 == unsigned_intTI_type_node)
1808     return intTI_type_node;
1809 #endif
1810   if (type1 == unsigned_intDI_type_node)
1811     return intDI_type_node;
1812   if (type1 == unsigned_intSI_type_node)
1813     return intSI_type_node;
1814   if (type1 == unsigned_intHI_type_node)
1815     return intHI_type_node;
1816   if (type1 == unsigned_intQI_type_node)
1817     return intQI_type_node;
1818
1819   return c_common_signed_or_unsigned_type (0, type);
1820 }
1821
1822 /* Return a type the same as TYPE except unsigned or
1823    signed according to UNSIGNEDP.  */
1824
1825 tree
1826 c_common_signed_or_unsigned_type (int unsignedp, tree type)
1827 {
1828   if (!INTEGRAL_TYPE_P (type)
1829       || TYPE_UNSIGNED (type) == unsignedp)
1830     return type;
1831
1832   /* For ENUMERAL_TYPEs in C++, must check the mode of the types, not
1833      the precision; they have precision set to match their range, but
1834      may use a wider mode to match an ABI.  If we change modes, we may
1835      wind up with bad conversions.  For INTEGER_TYPEs in C, must check
1836      the precision as well, so as to yield correct results for
1837      bit-field types.  C++ does not have these separate bit-field
1838      types, and producing a signed or unsigned variant of an
1839      ENUMERAL_TYPE may cause other problems as well.  */
1840
1841 #define TYPE_OK(node)                                                       \
1842   (TYPE_MODE (type) == TYPE_MODE (node)                                     \
1843    && (c_dialect_cxx () || TYPE_PRECISION (type) == TYPE_PRECISION (node)))
1844   if (TYPE_OK (signed_char_type_node))
1845     return unsignedp ? unsigned_char_type_node : signed_char_type_node;
1846   if (TYPE_OK (integer_type_node))
1847     return unsignedp ? unsigned_type_node : integer_type_node;
1848   if (TYPE_OK (short_integer_type_node))
1849     return unsignedp ? short_unsigned_type_node : short_integer_type_node;
1850   if (TYPE_OK (long_integer_type_node))
1851     return unsignedp ? long_unsigned_type_node : long_integer_type_node;
1852   if (TYPE_OK (long_long_integer_type_node))
1853     return (unsignedp ? long_long_unsigned_type_node
1854             : long_long_integer_type_node);
1855   if (TYPE_OK (widest_integer_literal_type_node))
1856     return (unsignedp ? widest_unsigned_literal_type_node
1857             : widest_integer_literal_type_node);
1858
1859 #if HOST_BITS_PER_WIDE_INT >= 64
1860   if (TYPE_OK (intTI_type_node))
1861     return unsignedp ? unsigned_intTI_type_node : intTI_type_node;
1862 #endif
1863   if (TYPE_OK (intDI_type_node))
1864     return unsignedp ? unsigned_intDI_type_node : intDI_type_node;
1865   if (TYPE_OK (intSI_type_node))
1866     return unsignedp ? unsigned_intSI_type_node : intSI_type_node;
1867   if (TYPE_OK (intHI_type_node))
1868     return unsignedp ? unsigned_intHI_type_node : intHI_type_node;
1869   if (TYPE_OK (intQI_type_node))
1870     return unsignedp ? unsigned_intQI_type_node : intQI_type_node;
1871 #undef TYPE_OK
1872
1873   if (c_dialect_cxx ())
1874     return type;
1875   else
1876     return build_nonstandard_integer_type (TYPE_PRECISION (type), unsignedp);
1877 }
1878
1879 /* Build a bit-field integer type for the given WIDTH and UNSIGNEDP.  */
1880
1881 tree
1882 c_build_bitfield_integer_type (unsigned HOST_WIDE_INT width, int unsignedp)
1883 {
1884   /* Extended integer types of the same width as a standard type have
1885      lesser rank, so those of the same width as int promote to int or
1886      unsigned int and are valid for printf formats expecting int or
1887      unsigned int.  To avoid such special cases, avoid creating
1888      extended integer types for bit-fields if a standard integer type
1889      is available.  */
1890   if (width == TYPE_PRECISION (integer_type_node))
1891     return unsignedp ? unsigned_type_node : integer_type_node;
1892   if (width == TYPE_PRECISION (signed_char_type_node))
1893     return unsignedp ? unsigned_char_type_node : signed_char_type_node;
1894   if (width == TYPE_PRECISION (short_integer_type_node))
1895     return unsignedp ? short_unsigned_type_node : short_integer_type_node;
1896   if (width == TYPE_PRECISION (long_integer_type_node))
1897     return unsignedp ? long_unsigned_type_node : long_integer_type_node;
1898   if (width == TYPE_PRECISION (long_long_integer_type_node))
1899     return (unsignedp ? long_long_unsigned_type_node
1900             : long_long_integer_type_node);
1901   return build_nonstandard_integer_type (width, unsignedp);
1902 }
1903
1904 /* The C version of the register_builtin_type langhook.  */
1905
1906 void
1907 c_register_builtin_type (tree type, const char* name)
1908 {
1909   tree decl;
1910
1911   decl = build_decl (TYPE_DECL, get_identifier (name), type);
1912   DECL_ARTIFICIAL (decl) = 1;
1913   if (!TYPE_NAME (type))
1914     TYPE_NAME (type) = decl;
1915   pushdecl (decl);
1916
1917   registered_builtin_types = tree_cons (0, type, registered_builtin_types);
1918 }
1919
1920 \f
1921 /* Return the minimum number of bits needed to represent VALUE in a
1922    signed or unsigned type, UNSIGNEDP says which.  */
1923
1924 unsigned int
1925 min_precision (tree value, int unsignedp)
1926 {
1927   int log;
1928
1929   /* If the value is negative, compute its negative minus 1.  The latter
1930      adjustment is because the absolute value of the largest negative value
1931      is one larger than the largest positive value.  This is equivalent to
1932      a bit-wise negation, so use that operation instead.  */
1933
1934   if (tree_int_cst_sgn (value) < 0)
1935     value = fold_build1 (BIT_NOT_EXPR, TREE_TYPE (value), value);
1936
1937   /* Return the number of bits needed, taking into account the fact
1938      that we need one more bit for a signed than unsigned type.  */
1939
1940   if (integer_zerop (value))
1941     log = 0;
1942   else
1943     log = tree_floor_log2 (value);
1944
1945   return log + 1 + !unsignedp;
1946 }
1947 \f
1948 /* Print an error message for invalid operands to arith operation
1949    CODE.  */
1950
1951 void
1952 binary_op_error (enum tree_code code)
1953 {
1954   const char *opname;
1955
1956   switch (code)
1957     {
1958     case PLUS_EXPR:
1959       opname = "+"; break;
1960     case MINUS_EXPR:
1961       opname = "-"; break;
1962     case MULT_EXPR:
1963       opname = "*"; break;
1964     case MAX_EXPR:
1965       opname = "max"; break;
1966     case MIN_EXPR:
1967       opname = "min"; break;
1968     case EQ_EXPR:
1969       opname = "=="; break;
1970     case NE_EXPR:
1971       opname = "!="; break;
1972     case LE_EXPR:
1973       opname = "<="; break;
1974     case GE_EXPR:
1975       opname = ">="; break;
1976     case LT_EXPR:
1977       opname = "<"; break;
1978     case GT_EXPR:
1979       opname = ">"; break;
1980     case LSHIFT_EXPR:
1981       opname = "<<"; break;
1982     case RSHIFT_EXPR:
1983       opname = ">>"; break;
1984     case TRUNC_MOD_EXPR:
1985     case FLOOR_MOD_EXPR:
1986       opname = "%"; break;
1987     case TRUNC_DIV_EXPR:
1988     case FLOOR_DIV_EXPR:
1989       opname = "/"; break;
1990     case BIT_AND_EXPR:
1991       opname = "&"; break;
1992     case BIT_IOR_EXPR:
1993       opname = "|"; break;
1994     case TRUTH_ANDIF_EXPR:
1995       opname = "&&"; break;
1996     case TRUTH_ORIF_EXPR:
1997       opname = "||"; break;
1998     case BIT_XOR_EXPR:
1999       opname = "^"; break;
2000     default:
2001       gcc_unreachable ();
2002     }
2003   error ("invalid operands to binary %s", opname);
2004 }
2005 \f
2006 /* Subroutine of build_binary_op, used for comparison operations.
2007    See if the operands have both been converted from subword integer types
2008    and, if so, perhaps change them both back to their original type.
2009    This function is also responsible for converting the two operands
2010    to the proper common type for comparison.
2011
2012    The arguments of this function are all pointers to local variables
2013    of build_binary_op: OP0_PTR is &OP0, OP1_PTR is &OP1,
2014    RESTYPE_PTR is &RESULT_TYPE and RESCODE_PTR is &RESULTCODE.
2015
2016    If this function returns nonzero, it means that the comparison has
2017    a constant value.  What this function returns is an expression for
2018    that value.  */
2019
2020 tree
2021 shorten_compare (tree *op0_ptr, tree *op1_ptr, tree *restype_ptr,
2022                  enum tree_code *rescode_ptr)
2023 {
2024   tree type;
2025   tree op0 = *op0_ptr;
2026   tree op1 = *op1_ptr;
2027   int unsignedp0, unsignedp1;
2028   int real1, real2;
2029   tree primop0, primop1;
2030   enum tree_code code = *rescode_ptr;
2031
2032   /* Throw away any conversions to wider types
2033      already present in the operands.  */
2034
2035   primop0 = get_narrower (op0, &unsignedp0);
2036   primop1 = get_narrower (op1, &unsignedp1);
2037
2038   /* Handle the case that OP0 does not *contain* a conversion
2039      but it *requires* conversion to FINAL_TYPE.  */
2040
2041   if (op0 == primop0 && TREE_TYPE (op0) != *restype_ptr)
2042     unsignedp0 = TYPE_UNSIGNED (TREE_TYPE (op0));
2043   if (op1 == primop1 && TREE_TYPE (op1) != *restype_ptr)
2044     unsignedp1 = TYPE_UNSIGNED (TREE_TYPE (op1));
2045
2046   /* If one of the operands must be floated, we cannot optimize.  */
2047   real1 = TREE_CODE (TREE_TYPE (primop0)) == REAL_TYPE;
2048   real2 = TREE_CODE (TREE_TYPE (primop1)) == REAL_TYPE;
2049
2050   /* If first arg is constant, swap the args (changing operation
2051      so value is preserved), for canonicalization.  Don't do this if
2052      the second arg is 0.  */
2053
2054   if (TREE_CONSTANT (primop0)
2055       && !integer_zerop (primop1) && !real_zerop (primop1))
2056     {
2057       tree tem = primop0;
2058       int temi = unsignedp0;
2059       primop0 = primop1;
2060       primop1 = tem;
2061       tem = op0;
2062       op0 = op1;
2063       op1 = tem;
2064       *op0_ptr = op0;
2065       *op1_ptr = op1;
2066       unsignedp0 = unsignedp1;
2067       unsignedp1 = temi;
2068       temi = real1;
2069       real1 = real2;
2070       real2 = temi;
2071
2072       switch (code)
2073         {
2074         case LT_EXPR:
2075           code = GT_EXPR;
2076           break;
2077         case GT_EXPR:
2078           code = LT_EXPR;
2079           break;
2080         case LE_EXPR:
2081           code = GE_EXPR;
2082           break;
2083         case GE_EXPR:
2084           code = LE_EXPR;
2085           break;
2086         default:
2087           break;
2088         }
2089       *rescode_ptr = code;
2090     }
2091
2092   /* If comparing an integer against a constant more bits wide,
2093      maybe we can deduce a value of 1 or 0 independent of the data.
2094      Or else truncate the constant now
2095      rather than extend the variable at run time.
2096
2097      This is only interesting if the constant is the wider arg.
2098      Also, it is not safe if the constant is unsigned and the
2099      variable arg is signed, since in this case the variable
2100      would be sign-extended and then regarded as unsigned.
2101      Our technique fails in this case because the lowest/highest
2102      possible unsigned results don't follow naturally from the
2103      lowest/highest possible values of the variable operand.
2104      For just EQ_EXPR and NE_EXPR there is another technique that
2105      could be used: see if the constant can be faithfully represented
2106      in the other operand's type, by truncating it and reextending it
2107      and see if that preserves the constant's value.  */
2108
2109   if (!real1 && !real2
2110       && TREE_CODE (primop1) == INTEGER_CST
2111       && TYPE_PRECISION (TREE_TYPE (primop0)) < TYPE_PRECISION (*restype_ptr))
2112     {
2113       int min_gt, max_gt, min_lt, max_lt;
2114       tree maxval, minval;
2115       /* 1 if comparison is nominally unsigned.  */
2116       int unsignedp = TYPE_UNSIGNED (*restype_ptr);
2117       tree val;
2118
2119       type = c_common_signed_or_unsigned_type (unsignedp0,
2120                                                TREE_TYPE (primop0));
2121
2122       maxval = TYPE_MAX_VALUE (type);
2123       minval = TYPE_MIN_VALUE (type);
2124
2125       if (unsignedp && !unsignedp0)
2126         *restype_ptr = c_common_signed_type (*restype_ptr);
2127
2128       if (TREE_TYPE (primop1) != *restype_ptr)
2129         {
2130           /* Convert primop1 to target type, but do not introduce
2131              additional overflow.  We know primop1 is an int_cst.  */
2132           tree tmp = build_int_cst_wide (*restype_ptr,
2133                                          TREE_INT_CST_LOW (primop1),
2134                                          TREE_INT_CST_HIGH (primop1));
2135
2136           primop1 = force_fit_type (tmp, 0, TREE_OVERFLOW (primop1),
2137                                     TREE_CONSTANT_OVERFLOW (primop1));
2138         }
2139       if (type != *restype_ptr)
2140         {
2141           minval = convert (*restype_ptr, minval);
2142           maxval = convert (*restype_ptr, maxval);
2143         }
2144
2145       if (unsignedp && unsignedp0)
2146         {
2147           min_gt = INT_CST_LT_UNSIGNED (primop1, minval);
2148           max_gt = INT_CST_LT_UNSIGNED (primop1, maxval);
2149           min_lt = INT_CST_LT_UNSIGNED (minval, primop1);
2150           max_lt = INT_CST_LT_UNSIGNED (maxval, primop1);
2151         }
2152       else
2153         {
2154           min_gt = INT_CST_LT (primop1, minval);
2155           max_gt = INT_CST_LT (primop1, maxval);
2156           min_lt = INT_CST_LT (minval, primop1);
2157           max_lt = INT_CST_LT (maxval, primop1);
2158         }
2159
2160       val = 0;
2161       /* This used to be a switch, but Genix compiler can't handle that.  */
2162       if (code == NE_EXPR)
2163         {
2164           if (max_lt || min_gt)
2165             val = truthvalue_true_node;
2166         }
2167       else if (code == EQ_EXPR)
2168         {
2169           if (max_lt || min_gt)
2170             val = truthvalue_false_node;
2171         }
2172       else if (code == LT_EXPR)
2173         {
2174           if (max_lt)
2175             val = truthvalue_true_node;
2176           if (!min_lt)
2177             val = truthvalue_false_node;
2178         }
2179       else if (code == GT_EXPR)
2180         {
2181           if (min_gt)
2182             val = truthvalue_true_node;
2183           if (!max_gt)
2184             val = truthvalue_false_node;
2185         }
2186       else if (code == LE_EXPR)
2187         {
2188           if (!max_gt)
2189             val = truthvalue_true_node;
2190           if (min_gt)
2191             val = truthvalue_false_node;
2192         }
2193       else if (code == GE_EXPR)
2194         {
2195           if (!min_lt)
2196             val = truthvalue_true_node;
2197           if (max_lt)
2198             val = truthvalue_false_node;
2199         }
2200
2201       /* If primop0 was sign-extended and unsigned comparison specd,
2202          we did a signed comparison above using the signed type bounds.
2203          But the comparison we output must be unsigned.
2204
2205          Also, for inequalities, VAL is no good; but if the signed
2206          comparison had *any* fixed result, it follows that the
2207          unsigned comparison just tests the sign in reverse
2208          (positive values are LE, negative ones GE).
2209          So we can generate an unsigned comparison
2210          against an extreme value of the signed type.  */
2211
2212       if (unsignedp && !unsignedp0)
2213         {
2214           if (val != 0)
2215             switch (code)
2216               {
2217               case LT_EXPR:
2218               case GE_EXPR:
2219                 primop1 = TYPE_MIN_VALUE (type);
2220                 val = 0;
2221                 break;
2222
2223               case LE_EXPR:
2224               case GT_EXPR:
2225                 primop1 = TYPE_MAX_VALUE (type);
2226                 val = 0;
2227                 break;
2228
2229               default:
2230                 break;
2231               }
2232           type = c_common_unsigned_type (type);
2233         }
2234
2235       if (TREE_CODE (primop0) != INTEGER_CST)
2236         {
2237           if (val == truthvalue_false_node)
2238             warning (0, "comparison is always false due to limited range of data type");
2239           if (val == truthvalue_true_node)
2240             warning (0, "comparison is always true due to limited range of data type");
2241         }
2242
2243       if (val != 0)
2244         {
2245           /* Don't forget to evaluate PRIMOP0 if it has side effects.  */
2246           if (TREE_SIDE_EFFECTS (primop0))
2247             return build2 (COMPOUND_EXPR, TREE_TYPE (val), primop0, val);
2248           return val;
2249         }
2250
2251       /* Value is not predetermined, but do the comparison
2252          in the type of the operand that is not constant.
2253          TYPE is already properly set.  */
2254     }
2255
2256   /* If either arg is decimal float and the other is float, find the
2257      proper common type to use for comparison.  */
2258   else if (real1 && real2
2259            && (DECIMAL_FLOAT_MODE_P (TYPE_MODE (TREE_TYPE (primop0)))
2260                || DECIMAL_FLOAT_MODE_P (TYPE_MODE (TREE_TYPE (primop1)))))
2261     type = common_type (TREE_TYPE (primop0), TREE_TYPE (primop1));
2262
2263   else if (real1 && real2
2264            && (TYPE_PRECISION (TREE_TYPE (primop0))
2265                == TYPE_PRECISION (TREE_TYPE (primop1))))
2266     type = TREE_TYPE (primop0);
2267
2268   /* If args' natural types are both narrower than nominal type
2269      and both extend in the same manner, compare them
2270      in the type of the wider arg.
2271      Otherwise must actually extend both to the nominal
2272      common type lest different ways of extending
2273      alter the result.
2274      (eg, (short)-1 == (unsigned short)-1  should be 0.)  */
2275
2276   else if (unsignedp0 == unsignedp1 && real1 == real2
2277            && TYPE_PRECISION (TREE_TYPE (primop0)) < TYPE_PRECISION (*restype_ptr)
2278            && TYPE_PRECISION (TREE_TYPE (primop1)) < TYPE_PRECISION (*restype_ptr))
2279     {
2280       type = common_type (TREE_TYPE (primop0), TREE_TYPE (primop1));
2281       type = c_common_signed_or_unsigned_type (unsignedp0
2282                                                || TYPE_UNSIGNED (*restype_ptr),
2283                                                type);
2284       /* Make sure shorter operand is extended the right way
2285          to match the longer operand.  */
2286       primop0
2287         = convert (c_common_signed_or_unsigned_type (unsignedp0,
2288                                                      TREE_TYPE (primop0)),
2289                    primop0);
2290       primop1
2291         = convert (c_common_signed_or_unsigned_type (unsignedp1,
2292                                                      TREE_TYPE (primop1)),
2293                    primop1);
2294     }
2295   else
2296     {
2297       /* Here we must do the comparison on the nominal type
2298          using the args exactly as we received them.  */
2299       type = *restype_ptr;
2300       primop0 = op0;
2301       primop1 = op1;
2302
2303       if (!real1 && !real2 && integer_zerop (primop1)
2304           && TYPE_UNSIGNED (*restype_ptr))
2305         {
2306           tree value = 0;
2307           switch (code)
2308             {
2309             case GE_EXPR:
2310               /* All unsigned values are >= 0, so we warn if extra warnings
2311                  are requested.  However, if OP0 is a constant that is
2312                  >= 0, the signedness of the comparison isn't an issue,
2313                  so suppress the warning.  */
2314               if (extra_warnings && !in_system_header
2315                   && !(TREE_CODE (primop0) == INTEGER_CST
2316                        && !TREE_OVERFLOW (convert (c_common_signed_type (type),
2317                                                    primop0))))
2318                 warning (0, "comparison of unsigned expression >= 0 is always true");
2319               value = truthvalue_true_node;
2320               break;
2321
2322             case LT_EXPR:
2323               if (extra_warnings && !in_system_header
2324                   && !(TREE_CODE (primop0) == INTEGER_CST
2325                        && !TREE_OVERFLOW (convert (c_common_signed_type (type),
2326                                                    primop0))))
2327                 warning (0, "comparison of unsigned expression < 0 is always false");
2328               value = truthvalue_false_node;
2329               break;
2330
2331             default:
2332               break;
2333             }
2334
2335           if (value != 0)
2336             {
2337               /* Don't forget to evaluate PRIMOP0 if it has side effects.  */
2338               if (TREE_SIDE_EFFECTS (primop0))
2339                 return build2 (COMPOUND_EXPR, TREE_TYPE (value),
2340                                primop0, value);
2341               return value;
2342             }
2343         }
2344     }
2345
2346   *op0_ptr = convert (type, primop0);
2347   *op1_ptr = convert (type, primop1);
2348
2349   *restype_ptr = truthvalue_type_node;
2350
2351   return 0;
2352 }
2353 \f
2354 /* Return a tree for the sum or difference (RESULTCODE says which)
2355    of pointer PTROP and integer INTOP.  */
2356
2357 tree
2358 pointer_int_sum (enum tree_code resultcode, tree ptrop, tree intop)
2359 {
2360   tree size_exp;
2361
2362   /* The result is a pointer of the same type that is being added.  */
2363
2364   tree result_type = TREE_TYPE (ptrop);
2365
2366   if (TREE_CODE (TREE_TYPE (result_type)) == VOID_TYPE)
2367     {
2368       if (pedantic || warn_pointer_arith)
2369         pedwarn ("pointer of type %<void *%> used in arithmetic");
2370       size_exp = integer_one_node;
2371     }
2372   else if (TREE_CODE (TREE_TYPE (result_type)) == FUNCTION_TYPE)
2373     {
2374       if (pedantic || warn_pointer_arith)
2375         pedwarn ("pointer to a function used in arithmetic");
2376       size_exp = integer_one_node;
2377     }
2378   else if (TREE_CODE (TREE_TYPE (result_type)) == METHOD_TYPE)
2379     {
2380       if (pedantic || warn_pointer_arith)
2381         pedwarn ("pointer to member function used in arithmetic");
2382       size_exp = integer_one_node;
2383     }
2384   else
2385     size_exp = size_in_bytes (TREE_TYPE (result_type));
2386
2387   /* If what we are about to multiply by the size of the elements
2388      contains a constant term, apply distributive law
2389      and multiply that constant term separately.
2390      This helps produce common subexpressions.  */
2391
2392   if ((TREE_CODE (intop) == PLUS_EXPR || TREE_CODE (intop) == MINUS_EXPR)
2393       && !TREE_CONSTANT (intop)
2394       && TREE_CONSTANT (TREE_OPERAND (intop, 1))
2395       && TREE_CONSTANT (size_exp)
2396       /* If the constant comes from pointer subtraction,
2397          skip this optimization--it would cause an error.  */
2398       && TREE_CODE (TREE_TYPE (TREE_OPERAND (intop, 0))) == INTEGER_TYPE
2399       /* If the constant is unsigned, and smaller than the pointer size,
2400          then we must skip this optimization.  This is because it could cause
2401          an overflow error if the constant is negative but INTOP is not.  */
2402       && (!TYPE_UNSIGNED (TREE_TYPE (intop))
2403           || (TYPE_PRECISION (TREE_TYPE (intop))
2404               == TYPE_PRECISION (TREE_TYPE (ptrop)))))
2405     {
2406       enum tree_code subcode = resultcode;
2407       tree int_type = TREE_TYPE (intop);
2408       if (TREE_CODE (intop) == MINUS_EXPR)
2409         subcode = (subcode == PLUS_EXPR ? MINUS_EXPR : PLUS_EXPR);
2410       /* Convert both subexpression types to the type of intop,
2411          because weird cases involving pointer arithmetic
2412          can result in a sum or difference with different type args.  */
2413       ptrop = build_binary_op (subcode, ptrop,
2414                                convert (int_type, TREE_OPERAND (intop, 1)), 1);
2415       intop = convert (int_type, TREE_OPERAND (intop, 0));
2416     }
2417
2418   /* Convert the integer argument to a type the same size as sizetype
2419      so the multiply won't overflow spuriously.  */
2420
2421   if (TYPE_PRECISION (TREE_TYPE (intop)) != TYPE_PRECISION (sizetype)
2422       || TYPE_UNSIGNED (TREE_TYPE (intop)) != TYPE_UNSIGNED (sizetype))
2423     intop = convert (c_common_type_for_size (TYPE_PRECISION (sizetype),
2424                                              TYPE_UNSIGNED (sizetype)), intop);
2425
2426   /* Replace the integer argument with a suitable product by the object size.
2427      Do this multiplication as signed, then convert to the appropriate
2428      pointer type (actually unsigned integral).  */
2429
2430   intop = convert (result_type,
2431                    build_binary_op (MULT_EXPR, intop,
2432                                     convert (TREE_TYPE (intop), size_exp), 1));
2433
2434   /* Create the sum or difference.  */
2435   return fold_build2 (resultcode, result_type, ptrop, intop);
2436 }
2437 \f
2438 /* Prepare expr to be an argument of a TRUTH_NOT_EXPR,
2439    or for an `if' or `while' statement or ?..: exp.  It should already
2440    have been validated to be of suitable type; otherwise, a bad
2441    diagnostic may result.
2442
2443    This preparation consists of taking the ordinary
2444    representation of an expression expr and producing a valid tree
2445    boolean expression describing whether expr is nonzero.  We could
2446    simply always do build_binary_op (NE_EXPR, expr, truthvalue_false_node, 1),
2447    but we optimize comparisons, &&, ||, and !.
2448
2449    The resulting type should always be `truthvalue_type_node'.  */
2450
2451 tree
2452 c_common_truthvalue_conversion (tree expr)
2453 {
2454   switch (TREE_CODE (expr))
2455     {
2456     case EQ_EXPR:   case NE_EXPR:   case UNEQ_EXPR: case LTGT_EXPR:
2457     case LE_EXPR:   case GE_EXPR:   case LT_EXPR:   case GT_EXPR:
2458     case UNLE_EXPR: case UNGE_EXPR: case UNLT_EXPR: case UNGT_EXPR:
2459     case ORDERED_EXPR: case UNORDERED_EXPR:
2460       if (TREE_TYPE (expr) == truthvalue_type_node)
2461         return expr;
2462       return build2 (TREE_CODE (expr), truthvalue_type_node,
2463                      TREE_OPERAND (expr, 0), TREE_OPERAND (expr, 1));
2464
2465     case TRUTH_ANDIF_EXPR:
2466     case TRUTH_ORIF_EXPR:
2467     case TRUTH_AND_EXPR:
2468     case TRUTH_OR_EXPR:
2469     case TRUTH_XOR_EXPR:
2470       if (TREE_TYPE (expr) == truthvalue_type_node)
2471         return expr;
2472       return build2 (TREE_CODE (expr), truthvalue_type_node,
2473                  c_common_truthvalue_conversion (TREE_OPERAND (expr, 0)),
2474                  c_common_truthvalue_conversion (TREE_OPERAND (expr, 1)));
2475
2476     case TRUTH_NOT_EXPR:
2477       if (TREE_TYPE (expr) == truthvalue_type_node)
2478         return expr;
2479       return build1 (TREE_CODE (expr), truthvalue_type_node,
2480                  c_common_truthvalue_conversion (TREE_OPERAND (expr, 0)));
2481
2482     case ERROR_MARK:
2483       return expr;
2484
2485     case INTEGER_CST:
2486       /* Avoid integer_zerop to ignore TREE_CONSTANT_OVERFLOW.  */
2487       return (TREE_INT_CST_LOW (expr) != 0 || TREE_INT_CST_HIGH (expr) != 0)
2488              ? truthvalue_true_node
2489              : truthvalue_false_node;
2490
2491     case REAL_CST:
2492       return real_compare (NE_EXPR, &TREE_REAL_CST (expr), &dconst0)
2493              ? truthvalue_true_node
2494              : truthvalue_false_node;
2495
2496     case FUNCTION_DECL:
2497       expr = build_unary_op (ADDR_EXPR, expr, 0);
2498       /* Fall through.  */
2499
2500     case ADDR_EXPR:
2501       {
2502         tree inner = TREE_OPERAND (expr, 0);
2503         if (DECL_P (inner)
2504             && (TREE_CODE (inner) == PARM_DECL
2505                 || TREE_CODE (inner) == LABEL_DECL
2506                 || !DECL_WEAK (inner)))
2507           {
2508             /* Common Ada/Pascal programmer's mistake.  We always warn
2509                about this since it is so bad.  */
2510             warning (OPT_Walways_true, "the address of %qD will always evaluate as %<true%>",
2511                      inner);
2512             return truthvalue_true_node;
2513           }
2514
2515         /* If we are taking the address of an external decl, it might be
2516            zero if it is weak, so we cannot optimize.  */
2517         if (DECL_P (inner)
2518             && DECL_EXTERNAL (inner))
2519           break;
2520
2521         if (TREE_SIDE_EFFECTS (inner))
2522           return build2 (COMPOUND_EXPR, truthvalue_type_node,
2523                          inner, truthvalue_true_node);
2524         else
2525           return truthvalue_true_node;
2526       }
2527
2528     case COMPLEX_EXPR:
2529       return build_binary_op ((TREE_SIDE_EFFECTS (TREE_OPERAND (expr, 1))
2530                                ? TRUTH_OR_EXPR : TRUTH_ORIF_EXPR),
2531                 c_common_truthvalue_conversion (TREE_OPERAND (expr, 0)),
2532                 c_common_truthvalue_conversion (TREE_OPERAND (expr, 1)),
2533                               0);
2534
2535     case NEGATE_EXPR:
2536     case ABS_EXPR:
2537     case FLOAT_EXPR:
2538       /* These don't change whether an object is nonzero or zero.  */
2539       return c_common_truthvalue_conversion (TREE_OPERAND (expr, 0));
2540
2541     case LROTATE_EXPR:
2542     case RROTATE_EXPR:
2543       /* These don't change whether an object is zero or nonzero, but
2544          we can't ignore them if their second arg has side-effects.  */
2545       if (TREE_SIDE_EFFECTS (TREE_OPERAND (expr, 1)))
2546         return build2 (COMPOUND_EXPR, truthvalue_type_node,
2547                        TREE_OPERAND (expr, 1),
2548                        c_common_truthvalue_conversion (TREE_OPERAND (expr, 0)));
2549       else
2550         return c_common_truthvalue_conversion (TREE_OPERAND (expr, 0));
2551
2552     case COND_EXPR:
2553       /* Distribute the conversion into the arms of a COND_EXPR.  */
2554       return fold_build3 (COND_EXPR, truthvalue_type_node,
2555                 TREE_OPERAND (expr, 0),
2556                 c_common_truthvalue_conversion (TREE_OPERAND (expr, 1)),
2557                 c_common_truthvalue_conversion (TREE_OPERAND (expr, 2)));
2558
2559     case CONVERT_EXPR:
2560     case NOP_EXPR:
2561       /* Don't cancel the effect of a CONVERT_EXPR from a REFERENCE_TYPE,
2562          since that affects how `default_conversion' will behave.  */
2563       if (TREE_CODE (TREE_TYPE (expr)) == REFERENCE_TYPE
2564           || TREE_CODE (TREE_TYPE (TREE_OPERAND (expr, 0))) == REFERENCE_TYPE)
2565         break;
2566       /* If this is widening the argument, we can ignore it.  */
2567       if (TYPE_PRECISION (TREE_TYPE (expr))
2568           >= TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (expr, 0))))
2569         return c_common_truthvalue_conversion (TREE_OPERAND (expr, 0));
2570       break;
2571
2572     case MODIFY_EXPR:
2573       if (!TREE_NO_WARNING (expr))
2574         warning (OPT_Wparentheses,
2575                  "suggest parentheses around assignment used as truth value");
2576       break;
2577
2578     default:
2579       break;
2580     }
2581
2582   if (TREE_CODE (TREE_TYPE (expr)) == COMPLEX_TYPE)
2583     {
2584       tree t = save_expr (expr);
2585       return (build_binary_op
2586               ((TREE_SIDE_EFFECTS (expr)
2587                 ? TRUTH_OR_EXPR : TRUTH_ORIF_EXPR),
2588         c_common_truthvalue_conversion (build_unary_op (REALPART_EXPR, t, 0)),
2589         c_common_truthvalue_conversion (build_unary_op (IMAGPART_EXPR, t, 0)),
2590                0));
2591     }
2592
2593   return build_binary_op (NE_EXPR, expr, integer_zero_node, 1);
2594 }
2595 \f
2596 static void def_builtin_1  (enum built_in_function fncode,
2597                             const char *name,
2598                             enum built_in_class fnclass,
2599                             tree fntype, tree libtype,
2600                             bool both_p, bool fallback_p, bool nonansi_p,
2601                             tree fnattrs, bool implicit_p);
2602
2603 /* Make a variant type in the proper way for C/C++, propagating qualifiers
2604    down to the element type of an array.  */
2605
2606 tree
2607 c_build_qualified_type (tree type, int type_quals)
2608 {
2609   if (type == error_mark_node)
2610     return type;
2611
2612   if (TREE_CODE (type) == ARRAY_TYPE)
2613     {
2614       tree t;
2615       tree element_type = c_build_qualified_type (TREE_TYPE (type),
2616                                                   type_quals);
2617
2618       /* See if we already have an identically qualified type.  */
2619       for (t = TYPE_MAIN_VARIANT (type); t; t = TYPE_NEXT_VARIANT (t))
2620         {
2621           if (TYPE_QUALS (strip_array_types (t)) == type_quals
2622               && TYPE_NAME (t) == TYPE_NAME (type)
2623               && TYPE_CONTEXT (t) == TYPE_CONTEXT (type)
2624               && attribute_list_equal (TYPE_ATTRIBUTES (t),
2625                                        TYPE_ATTRIBUTES (type)))
2626             break;
2627         }
2628       if (!t)
2629         {
2630           t = build_variant_type_copy (type);
2631           TREE_TYPE (t) = element_type;
2632         }
2633       return t;
2634     }
2635
2636   /* A restrict-qualified pointer type must be a pointer to object or
2637      incomplete type.  Note that the use of POINTER_TYPE_P also allows
2638      REFERENCE_TYPEs, which is appropriate for C++.  */
2639   if ((type_quals & TYPE_QUAL_RESTRICT)
2640       && (!POINTER_TYPE_P (type)
2641           || !C_TYPE_OBJECT_OR_INCOMPLETE_P (TREE_TYPE (type))))
2642     {
2643       error ("invalid use of %<restrict%>");
2644       type_quals &= ~TYPE_QUAL_RESTRICT;
2645     }
2646
2647   return build_qualified_type (type, type_quals);
2648 }
2649
2650 /* Apply the TYPE_QUALS to the new DECL.  */
2651
2652 void
2653 c_apply_type_quals_to_decl (int type_quals, tree decl)
2654 {
2655   tree type = TREE_TYPE (decl);
2656
2657   if (type == error_mark_node)
2658     return;
2659
2660   if (((type_quals & TYPE_QUAL_CONST)
2661        || (type && TREE_CODE (type) == REFERENCE_TYPE))
2662       /* An object declared 'const' is only readonly after it is
2663          initialized.  We don't have any way of expressing this currently,
2664          so we need to be conservative and unset TREE_READONLY for types
2665          with constructors.  Otherwise aliasing code will ignore stores in
2666          an inline constructor.  */
2667       && !(type && TYPE_NEEDS_CONSTRUCTING (type)))
2668     TREE_READONLY (decl) = 1;
2669   if (type_quals & TYPE_QUAL_VOLATILE)
2670     {
2671       TREE_SIDE_EFFECTS (decl) = 1;
2672       TREE_THIS_VOLATILE (decl) = 1;
2673     }
2674   if (type_quals & TYPE_QUAL_RESTRICT)
2675     {
2676       while (type && TREE_CODE (type) == ARRAY_TYPE)
2677         /* Allow 'restrict' on arrays of pointers.
2678            FIXME currently we just ignore it.  */
2679         type = TREE_TYPE (type);
2680       if (!type
2681           || !POINTER_TYPE_P (type)
2682           || !C_TYPE_OBJECT_OR_INCOMPLETE_P (TREE_TYPE (type)))
2683         error ("invalid use of %<restrict%>");
2684       else if (flag_strict_aliasing && type == TREE_TYPE (decl))
2685         /* Indicate we need to make a unique alias set for this pointer.
2686            We can't do it here because it might be pointing to an
2687            incomplete type.  */
2688         DECL_POINTER_ALIAS_SET (decl) = -2;
2689     }
2690 }
2691
2692 /* Hash function for the problem of multiple type definitions in
2693    different files.  This must hash all types that will compare
2694    equal via comptypes to the same value.  In practice it hashes
2695    on some of the simple stuff and leaves the details to comptypes.  */
2696
2697 static hashval_t
2698 c_type_hash (const void *p)
2699 {
2700   int i = 0;
2701   int shift, size;
2702   tree t = (tree) p;
2703   tree t2;
2704   switch (TREE_CODE (t))
2705     {
2706     /* For pointers, hash on pointee type plus some swizzling.  */
2707     case POINTER_TYPE:
2708       return c_type_hash (TREE_TYPE (t)) ^ 0x3003003;
2709     /* Hash on number of elements and total size.  */
2710     case ENUMERAL_TYPE:
2711       shift = 3;
2712       t2 = TYPE_VALUES (t);
2713       break;
2714     case RECORD_TYPE:
2715       shift = 0;
2716       t2 = TYPE_FIELDS (t);
2717       break;
2718     case QUAL_UNION_TYPE:
2719       shift = 1;
2720       t2 = TYPE_FIELDS (t);
2721       break;
2722     case UNION_TYPE:
2723       shift = 2;
2724       t2 = TYPE_FIELDS (t);
2725       break;
2726     default:
2727       gcc_unreachable ();
2728     }
2729   for (; t2; t2 = TREE_CHAIN (t2))
2730     i++;
2731   size = TREE_INT_CST_LOW (TYPE_SIZE (t));
2732   return ((size << 24) | (i << shift));
2733 }
2734
2735 static GTY((param_is (union tree_node))) htab_t type_hash_table;
2736
2737 /* Return the typed-based alias set for T, which may be an expression
2738    or a type.  Return -1 if we don't do anything special.  */
2739
2740 HOST_WIDE_INT
2741 c_common_get_alias_set (tree t)
2742 {
2743   tree u;
2744   PTR *slot;
2745
2746   /* Permit type-punning when accessing a union, provided the access
2747      is directly through the union.  For example, this code does not
2748      permit taking the address of a union member and then storing
2749      through it.  Even the type-punning allowed here is a GCC
2750      extension, albeit a common and useful one; the C standard says
2751      that such accesses have implementation-defined behavior.  */
2752   for (u = t;
2753        TREE_CODE (u) == COMPONENT_REF || TREE_CODE (u) == ARRAY_REF;
2754        u = TREE_OPERAND (u, 0))
2755     if (TREE_CODE (u) == COMPONENT_REF
2756         && TREE_CODE (TREE_TYPE (TREE_OPERAND (u, 0))) == UNION_TYPE)
2757       return 0;
2758
2759   /* That's all the expressions we handle specially.  */
2760   if (!TYPE_P (t))
2761     return -1;
2762
2763   /* The C standard guarantees that any object may be accessed via an
2764      lvalue that has character type.  */
2765   if (t == char_type_node
2766       || t == signed_char_type_node
2767       || t == unsigned_char_type_node)
2768     return 0;
2769
2770   /* If it has the may_alias attribute, it can alias anything.  */
2771   if (lookup_attribute ("may_alias", TYPE_ATTRIBUTES (t)))
2772     return 0;
2773
2774   /* The C standard specifically allows aliasing between signed and
2775      unsigned variants of the same type.  We treat the signed
2776      variant as canonical.  */
2777   if (TREE_CODE (t) == INTEGER_TYPE && TYPE_UNSIGNED (t))
2778     {
2779       tree t1 = c_common_signed_type (t);
2780
2781       /* t1 == t can happen for boolean nodes which are always unsigned.  */
2782       if (t1 != t)
2783         return get_alias_set (t1);
2784     }
2785   else if (POINTER_TYPE_P (t))
2786     {
2787       tree t1;
2788
2789       /* Unfortunately, there is no canonical form of a pointer type.
2790          In particular, if we have `typedef int I', then `int *', and
2791          `I *' are different types.  So, we have to pick a canonical
2792          representative.  We do this below.
2793
2794          Technically, this approach is actually more conservative that
2795          it needs to be.  In particular, `const int *' and `int *'
2796          should be in different alias sets, according to the C and C++
2797          standard, since their types are not the same, and so,
2798          technically, an `int **' and `const int **' cannot point at
2799          the same thing.
2800
2801          But, the standard is wrong.  In particular, this code is
2802          legal C++:
2803
2804             int *ip;
2805             int **ipp = &ip;
2806             const int* const* cipp = ipp;
2807
2808          And, it doesn't make sense for that to be legal unless you
2809          can dereference IPP and CIPP.  So, we ignore cv-qualifiers on
2810          the pointed-to types.  This issue has been reported to the
2811          C++ committee.  */
2812       t1 = build_type_no_quals (t);
2813       if (t1 != t)
2814         return get_alias_set (t1);
2815     }
2816
2817   /* Handle the case of multiple type nodes referring to "the same" type,
2818      which occurs with IMA.  These share an alias set.  FIXME:  Currently only
2819      C90 is handled.  (In C99 type compatibility is not transitive, which
2820      complicates things mightily. The alias set splay trees can theoretically
2821      represent this, but insertion is tricky when you consider all the
2822      different orders things might arrive in.) */
2823
2824   if (c_language != clk_c || flag_isoc99)
2825     return -1;
2826
2827   /* Save time if there's only one input file.  */
2828   if (num_in_fnames == 1)
2829     return -1;
2830
2831   /* Pointers need special handling if they point to any type that
2832      needs special handling (below).  */
2833   if (TREE_CODE (t) == POINTER_TYPE)
2834     {
2835       tree t2;
2836       /* Find bottom type under any nested POINTERs.  */
2837       for (t2 = TREE_TYPE (t);
2838      TREE_CODE (t2) == POINTER_TYPE;
2839      t2 = TREE_TYPE (t2))
2840   ;
2841       if (TREE_CODE (t2) != RECORD_TYPE
2842     && TREE_CODE (t2) != ENUMERAL_TYPE
2843     && TREE_CODE (t2) != QUAL_UNION_TYPE
2844     && TREE_CODE (t2) != UNION_TYPE)
2845   return -1;
2846       if (TYPE_SIZE (t2) == 0)
2847   return -1;
2848     }
2849   /* These are the only cases that need special handling.  */
2850   if (TREE_CODE (t) != RECORD_TYPE
2851       && TREE_CODE (t) != ENUMERAL_TYPE
2852       && TREE_CODE (t) != QUAL_UNION_TYPE
2853       && TREE_CODE (t) != UNION_TYPE
2854       && TREE_CODE (t) != POINTER_TYPE)
2855     return -1;
2856   /* Undefined? */
2857   if (TYPE_SIZE (t) == 0)
2858     return -1;
2859
2860   /* Look up t in hash table.  Only one of the compatible types within each
2861      alias set is recorded in the table.  */
2862   if (!type_hash_table)
2863     type_hash_table = htab_create_ggc (1021, c_type_hash,
2864             (htab_eq) lang_hooks.types_compatible_p,
2865             NULL);
2866   slot = htab_find_slot (type_hash_table, t, INSERT);
2867   if (*slot != NULL)
2868     {
2869       TYPE_ALIAS_SET (t) = TYPE_ALIAS_SET ((tree)*slot);
2870       return TYPE_ALIAS_SET ((tree)*slot);
2871     }
2872   else
2873     /* Our caller will assign and record (in t) a new alias set; all we need
2874        to do is remember t in the hash table.  */
2875     *slot = t;
2876
2877   return -1;
2878 }
2879 \f
2880 /* Compute the value of 'sizeof (TYPE)' or '__alignof__ (TYPE)', where the
2881    second parameter indicates which OPERATOR is being applied.  The COMPLAIN
2882    flag controls whether we should diagnose possibly ill-formed
2883    constructs or not.  */
2884
2885 tree
2886 c_sizeof_or_alignof_type (tree type, bool is_sizeof, int complain)
2887 {
2888   const char *op_name;
2889   tree value = NULL;
2890   enum tree_code type_code = TREE_CODE (type);
2891
2892   op_name = is_sizeof ? "sizeof" : "__alignof__";
2893
2894   if (type_code == FUNCTION_TYPE)
2895     {
2896       if (is_sizeof)
2897         {
2898           if (complain && (pedantic || warn_pointer_arith))
2899             pedwarn ("invalid application of %<sizeof%> to a function type");
2900           value = size_one_node;
2901         }
2902       else
2903         value = size_int (FUNCTION_BOUNDARY / BITS_PER_UNIT);
2904     }
2905   else if (type_code == VOID_TYPE || type_code == ERROR_MARK)
2906     {
2907       if (type_code == VOID_TYPE
2908           && complain && (pedantic || warn_pointer_arith))
2909         pedwarn ("invalid application of %qs to a void type", op_name);
2910       value = size_one_node;
2911     }
2912   else if (!COMPLETE_TYPE_P (type))
2913     {
2914       if (complain)
2915         error ("invalid application of %qs to incomplete type %qT ",
2916                op_name, type);
2917       value = size_zero_node;
2918     }
2919   else
2920     {
2921       if (is_sizeof)
2922         /* Convert in case a char is more than one unit.  */
2923         value = size_binop (CEIL_DIV_EXPR, TYPE_SIZE_UNIT (type),
2924                             size_int (TYPE_PRECISION (char_type_node)
2925                                       / BITS_PER_UNIT));
2926       else
2927         value = size_int (TYPE_ALIGN_UNIT (type));
2928     }
2929
2930   /* VALUE will have an integer type with TYPE_IS_SIZETYPE set.
2931      TYPE_IS_SIZETYPE means that certain things (like overflow) will
2932      never happen.  However, this node should really have type
2933      `size_t', which is just a typedef for an ordinary integer type.  */
2934   value = fold_convert (size_type_node, value);
2935   gcc_assert (!TYPE_IS_SIZETYPE (TREE_TYPE (value)));
2936
2937   return value;
2938 }
2939
2940 /* Implement the __alignof keyword: Return the minimum required
2941    alignment of EXPR, measured in bytes.  For VAR_DECL's and
2942    FIELD_DECL's return DECL_ALIGN (which can be set from an
2943    "aligned" __attribute__ specification).  */
2944
2945 tree
2946 c_alignof_expr (tree expr)
2947 {
2948   tree t;
2949
2950   if (TREE_CODE (expr) == VAR_DECL)
2951     t = size_int (DECL_ALIGN_UNIT (expr));
2952
2953   else if (TREE_CODE (expr) == COMPONENT_REF
2954            && DECL_C_BIT_FIELD (TREE_OPERAND (expr, 1)))
2955     {
2956       error ("%<__alignof%> applied to a bit-field");
2957       t = size_one_node;
2958     }
2959   else if (TREE_CODE (expr) == COMPONENT_REF
2960            && TREE_CODE (TREE_OPERAND (expr, 1)) == FIELD_DECL)
2961     t = size_int (DECL_ALIGN_UNIT (TREE_OPERAND (expr, 1)));
2962
2963   else if (TREE_CODE (expr) == INDIRECT_REF)
2964     {
2965       tree t = TREE_OPERAND (expr, 0);
2966       tree best = t;
2967       int bestalign = TYPE_ALIGN (TREE_TYPE (TREE_TYPE (t)));
2968
2969       while ((TREE_CODE (t) == NOP_EXPR || TREE_CODE (t) == CONVERT_EXPR)
2970              && TREE_CODE (TREE_TYPE (TREE_OPERAND (t, 0))) == POINTER_TYPE)
2971         {
2972           int thisalign;
2973
2974           t = TREE_OPERAND (t, 0);
2975           thisalign = TYPE_ALIGN (TREE_TYPE (TREE_TYPE (t)));
2976           if (thisalign > bestalign)
2977             best = t, bestalign = thisalign;
2978         }
2979       return c_alignof (TREE_TYPE (TREE_TYPE (best)));
2980     }
2981   else
2982     return c_alignof (TREE_TYPE (expr));
2983
2984   return fold_convert (size_type_node, t);
2985 }
2986 \f
2987 /* Handle C and C++ default attributes.  */
2988
2989 enum built_in_attribute
2990 {
2991 #define DEF_ATTR_NULL_TREE(ENUM) ENUM,
2992 #define DEF_ATTR_INT(ENUM, VALUE) ENUM,
2993 #define DEF_ATTR_IDENT(ENUM, STRING) ENUM,
2994 #define DEF_ATTR_TREE_LIST(ENUM, PURPOSE, VALUE, CHAIN) ENUM,
2995 #include "builtin-attrs.def"
2996 #undef DEF_ATTR_NULL_TREE
2997 #undef DEF_ATTR_INT
2998 #undef DEF_ATTR_IDENT
2999 #undef DEF_ATTR_TREE_LIST
3000   ATTR_LAST
3001 };
3002
3003 static GTY(()) tree built_in_attributes[(int) ATTR_LAST];
3004
3005 static void c_init_attributes (void);
3006
3007 enum c_builtin_type
3008 {
3009 #define DEF_PRIMITIVE_TYPE(NAME, VALUE) NAME,
3010 #define DEF_FUNCTION_TYPE_0(NAME, RETURN) NAME,
3011 #define DEF_FUNCTION_TYPE_1(NAME, RETURN, ARG1) NAME,
3012 #define DEF_FUNCTION_TYPE_2(NAME, RETURN, ARG1, ARG2) NAME,
3013 #define DEF_FUNCTION_TYPE_3(NAME, RETURN, ARG1, ARG2, ARG3) NAME,
3014 #define DEF_FUNCTION_TYPE_4(NAME, RETURN, ARG1, ARG2, ARG3, ARG4) NAME,
3015 #define DEF_FUNCTION_TYPE_5(NAME, RETURN, ARG1, ARG2, ARG3, ARG4, ARG5) NAME,
3016 #define DEF_FUNCTION_TYPE_6(NAME, RETURN, ARG1, ARG2, ARG3, ARG4, ARG5, ARG6) NAME,
3017 #define DEF_FUNCTION_TYPE_7(NAME, RETURN, ARG1, ARG2, ARG3, ARG4, ARG5, ARG6, ARG7) NAME,
3018 #define DEF_FUNCTION_TYPE_VAR_0(NAME, RETURN) NAME,
3019 #define DEF_FUNCTION_TYPE_VAR_1(NAME, RETURN, ARG1) NAME,
3020 #define DEF_FUNCTION_TYPE_VAR_2(NAME, RETURN, ARG1, ARG2) NAME,
3021 #define DEF_FUNCTION_TYPE_VAR_3(NAME, RETURN, ARG1, ARG2, ARG3) NAME,
3022 #define DEF_FUNCTION_TYPE_VAR_4(NAME, RETURN, ARG1, ARG2, ARG3, ARG4) NAME,
3023 #define DEF_FUNCTION_TYPE_VAR_5(NAME, RETURN, ARG1, ARG2, ARG3, ARG4, ARG6) \
3024   NAME,
3025 #define DEF_POINTER_TYPE(NAME, TYPE) NAME,
3026 #include "builtin-types.def"
3027 #undef DEF_PRIMITIVE_TYPE
3028 #undef DEF_FUNCTION_TYPE_0
3029 #undef DEF_FUNCTION_TYPE_1
3030 #undef DEF_FUNCTION_TYPE_2
3031 #undef DEF_FUNCTION_TYPE_3
3032 #undef DEF_FUNCTION_TYPE_4
3033 #undef DEF_FUNCTION_TYPE_5
3034 #undef DEF_FUNCTION_TYPE_6
3035 #undef DEF_FUNCTION_TYPE_7
3036 #undef DEF_FUNCTION_TYPE_VAR_0
3037 #undef DEF_FUNCTION_TYPE_VAR_1
3038 #undef DEF_FUNCTION_TYPE_VAR_2
3039 #undef DEF_FUNCTION_TYPE_VAR_3
3040 #undef DEF_FUNCTION_TYPE_VAR_4
3041 #undef DEF_FUNCTION_TYPE_VAR_5
3042 #undef DEF_POINTER_TYPE
3043   BT_LAST
3044 };
3045
3046 typedef enum c_builtin_type builtin_type;
3047
3048 /* A temporary array for c_common_nodes_and_builtins.  Used in
3049    communication with def_fn_type.  */
3050 static tree builtin_types[(int) BT_LAST + 1];
3051
3052 /* A helper function for c_common_nodes_and_builtins.  Build function type
3053    for DEF with return type RET and N arguments.  If VAR is true, then the
3054    function should be variadic after those N arguments.
3055
3056    Takes special care not to ICE if any of the types involved are
3057    error_mark_node, which indicates that said type is not in fact available
3058    (see builtin_type_for_size).  In which case the function type as a whole
3059    should be error_mark_node.  */
3060
3061 static void
3062 def_fn_type (builtin_type def, builtin_type ret, bool var, int n, ...)
3063 {
3064   tree args = NULL, t;
3065   va_list list;
3066   int i;
3067
3068   va_start (list, n);
3069   for (i = 0; i < n; ++i)
3070     {
3071       builtin_type a = va_arg (list, builtin_type);
3072       t = builtin_types[a];
3073       if (t == error_mark_node)
3074         goto egress;
3075       args = tree_cons (NULL_TREE, t, args);
3076     }
3077   va_end (list);
3078
3079   args = nreverse (args);
3080   if (!var)
3081     args = chainon (args, void_list_node);
3082
3083   t = builtin_types[ret];
3084   if (t == error_mark_node)
3085     goto egress;
3086   t = build_function_type (t, args);
3087
3088  egress:
3089   builtin_types[def] = t;
3090 }
3091
3092 /* Build tree nodes and builtin functions common to both C and C++ language
3093    frontends.  */
3094
3095 void
3096 c_common_nodes_and_builtins (void)
3097 {
3098   int wchar_type_size;
3099   tree array_domain_type;
3100   tree va_list_ref_type_node;
3101   tree va_list_arg_type_node;
3102
3103   /* Define `int' and `char' first so that dbx will output them first.  */
3104   record_builtin_type (RID_INT, NULL, integer_type_node);
3105   record_builtin_type (RID_CHAR, "char", char_type_node);
3106
3107   /* `signed' is the same as `int'.  FIXME: the declarations of "signed",
3108      "unsigned long", "long long unsigned" and "unsigned short" were in C++
3109      but not C.  Are the conditionals here needed?  */
3110   if (c_dialect_cxx ())
3111     record_builtin_type (RID_SIGNED, NULL, integer_type_node);
3112   record_builtin_type (RID_LONG, "long int", long_integer_type_node);
3113   record_builtin_type (RID_UNSIGNED, "unsigned int", unsigned_type_node);
3114   record_builtin_type (RID_MAX, "long unsigned int",
3115                        long_unsigned_type_node);
3116   if (c_dialect_cxx ())
3117     record_builtin_type (RID_MAX, "unsigned long", long_unsigned_type_node);
3118   record_builtin_type (RID_MAX, "long long int",
3119                        long_long_integer_type_node);
3120   record_builtin_type (RID_MAX, "long long unsigned int",
3121                        long_long_unsigned_type_node);
3122   if (c_dialect_cxx ())
3123     record_builtin_type (RID_MAX, "long long unsigned",
3124                          long_long_unsigned_type_node);
3125   record_builtin_type (RID_SHORT, "short int", short_integer_type_node);
3126   record_builtin_type (RID_MAX, "short unsigned int",
3127                        short_unsigned_type_node);
3128   if (c_dialect_cxx ())
3129     record_builtin_type (RID_MAX, "unsigned short",
3130                          short_unsigned_type_node);
3131
3132   /* Define both `signed char' and `unsigned char'.  */
3133   record_builtin_type (RID_MAX, "signed char", signed_char_type_node);
3134   record_builtin_type (RID_MAX, "unsigned char", unsigned_char_type_node);
3135
3136   /* These are types that c_common_type_for_size and
3137      c_common_type_for_mode use.  */
3138   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
3139                                          intQI_type_node));
3140   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
3141                                          intHI_type_node));
3142   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
3143                                          intSI_type_node));
3144   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
3145                                          intDI_type_node));
3146 #if HOST_BITS_PER_WIDE_INT >= 64
3147   if (targetm.scalar_mode_supported_p (TImode))
3148     lang_hooks.decls.pushdecl (build_decl (TYPE_DECL,
3149                                            get_identifier ("__int128_t"),
3150                                            intTI_type_node));
3151 #endif
3152   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
3153                                          unsigned_intQI_type_node));
3154   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
3155                                          unsigned_intHI_type_node));
3156   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
3157                                          unsigned_intSI_type_node));
3158   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
3159                                          unsigned_intDI_type_node));
3160 #if HOST_BITS_PER_WIDE_INT >= 64
3161   if (targetm.scalar_mode_supported_p (TImode))
3162     lang_hooks.decls.pushdecl (build_decl (TYPE_DECL,
3163                                            get_identifier ("__uint128_t"),
3164                                            unsigned_intTI_type_node));
3165 #endif
3166
3167   /* Create the widest literal types.  */
3168   widest_integer_literal_type_node
3169     = make_signed_type (HOST_BITS_PER_WIDE_INT * 2);
3170   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
3171                                          widest_integer_literal_type_node));
3172
3173   widest_unsigned_literal_type_node
3174     = make_unsigned_type (HOST_BITS_PER_WIDE_INT * 2);
3175   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
3176                                          widest_unsigned_literal_type_node));
3177
3178   /* `unsigned long' is the standard type for sizeof.
3179      Note that stddef.h uses `unsigned long',
3180      and this must agree, even if long and int are the same size.  */
3181   size_type_node =
3182     TREE_TYPE (identifier_global_value (get_identifier (SIZE_TYPE)));
3183   signed_size_type_node = c_common_signed_type (size_type_node);
3184   set_sizetype (size_type_node);
3185
3186   pid_type_node =
3187     TREE_TYPE (identifier_global_value (get_identifier (PID_TYPE)));
3188
3189   build_common_tree_nodes_2 (flag_short_double);
3190
3191   record_builtin_type (RID_FLOAT, NULL, float_type_node);
3192   record_builtin_type (RID_DOUBLE, NULL, double_type_node);
3193   record_builtin_type (RID_MAX, "long double", long_double_type_node);
3194
3195   /* Only supported decimal floating point extension if the target
3196      actually supports underlying modes. */
3197   if (targetm.scalar_mode_supported_p (SDmode)
3198       && targetm.scalar_mode_supported_p (DDmode)
3199       && targetm.scalar_mode_supported_p (TDmode))
3200     {
3201       record_builtin_type (RID_DFLOAT32, NULL, dfloat32_type_node);
3202       record_builtin_type (RID_DFLOAT64, NULL, dfloat64_type_node);
3203       record_builtin_type (RID_DFLOAT128, NULL, dfloat128_type_node);
3204     }
3205
3206   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL,
3207                                          get_identifier ("complex int"),
3208                                          complex_integer_type_node));
3209   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL,
3210                                          get_identifier ("complex float"),
3211                                          complex_float_type_node));
3212   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL,
3213                                          get_identifier ("complex double"),
3214                                          complex_double_type_node));
3215   lang_hooks.decls.pushdecl
3216     (build_decl (TYPE_DECL, get_identifier ("complex long double"),
3217                  complex_long_double_type_node));
3218
3219   if (c_dialect_cxx ())
3220     /* For C++, make fileptr_type_node a distinct void * type until
3221        FILE type is defined.  */
3222     fileptr_type_node = build_variant_type_copy (ptr_type_node);
3223
3224   record_builtin_type (RID_VOID, NULL, void_type_node);
3225
3226   /* This node must not be shared.  */
3227   void_zero_node = make_node (INTEGER_CST);
3228   TREE_TYPE (void_zero_node) = void_type_node;
3229
3230   void_list_node = build_void_list_node ();
3231
3232   /* Make a type to be the domain of a few array types
3233      whose domains don't really matter.
3234      200 is small enough that it always fits in size_t
3235      and large enough that it can hold most function names for the
3236      initializations of __FUNCTION__ and __PRETTY_FUNCTION__.  */
3237   array_domain_type = build_index_type (size_int (200));
3238
3239   /* Make a type for arrays of characters.
3240      With luck nothing will ever really depend on the length of this
3241      array type.  */
3242   char_array_type_node
3243     = build_array_type (char_type_node, array_domain_type);
3244
3245   /* Likewise for arrays of ints.  */
3246   int_array_type_node
3247     = build_array_type (integer_type_node, array_domain_type);
3248
3249   string_type_node = build_pointer_type (char_type_node);
3250   const_string_type_node
3251     = build_pointer_type (build_qualified_type
3252                           (char_type_node, TYPE_QUAL_CONST));
3253
3254   /* This is special for C++ so functions can be overloaded.  */
3255   wchar_type_node = get_identifier (MODIFIED_WCHAR_TYPE);
3256   wchar_type_node = TREE_TYPE (identifier_global_value (wchar_type_node));
3257   wchar_type_size = TYPE_PRECISION (wchar_type_node);
3258   if (c_dialect_cxx ())
3259     {
3260       if (TYPE_UNSIGNED (wchar_type_node))
3261         wchar_type_node = make_unsigned_type (wchar_type_size);
3262       else
3263         wchar_type_node = make_signed_type (wchar_type_size);
3264       record_builtin_type (RID_WCHAR, "wchar_t", wchar_type_node);
3265     }
3266   else
3267     {
3268       signed_wchar_type_node = c_common_signed_type (wchar_type_node);
3269       unsigned_wchar_type_node = c_common_unsigned_type (wchar_type_node);
3270     }
3271
3272   /* This is for wide string constants.  */
3273   wchar_array_type_node
3274     = build_array_type (wchar_type_node, array_domain_type);
3275
3276   wint_type_node =
3277     TREE_TYPE (identifier_global_value (get_identifier (WINT_TYPE)));
3278
3279   intmax_type_node =
3280     TREE_TYPE (identifier_global_value (get_identifier (INTMAX_TYPE)));
3281   uintmax_type_node =
3282     TREE_TYPE (identifier_global_value (get_identifier (UINTMAX_TYPE)));
3283
3284   default_function_type = build_function_type (integer_type_node, NULL_TREE);
3285   ptrdiff_type_node
3286     = TREE_TYPE (identifier_global_value (get_identifier (PTRDIFF_TYPE)));
3287   unsigned_ptrdiff_type_node = c_common_unsigned_type (ptrdiff_type_node);
3288
3289   lang_hooks.decls.pushdecl
3290     (build_decl (TYPE_DECL, get_identifier ("__builtin_va_list"),
3291                  va_list_type_node));
3292
3293   if (TREE_CODE (va_list_type_node) == ARRAY_TYPE)
3294     {
3295       va_list_arg_type_node = va_list_ref_type_node =
3296         build_pointer_type (TREE_TYPE (va_list_type_node));
3297     }
3298   else
3299     {
3300       va_list_arg_type_node = va_list_type_node;
3301       va_list_ref_type_node = build_reference_type (va_list_type_node);
3302     }
3303
3304 #define DEF_PRIMITIVE_TYPE(ENUM, VALUE) \
3305   builtin_types[ENUM] = VALUE;
3306 #define DEF_FUNCTION_TYPE_0(ENUM, RETURN) \
3307   def_fn_type (ENUM, RETURN, 0, 0);
3308 #define DEF_FUNCTION_TYPE_1(ENUM, RETURN, ARG1) \
3309   def_fn_type (ENUM, RETURN, 0, 1, ARG1);
3310 #define DEF_FUNCTION_TYPE_2(ENUM, RETURN, ARG1, ARG2) \
3311   def_fn_type (ENUM, RETURN, 0, 2, ARG1, ARG2);
3312 #define DEF_FUNCTION_TYPE_3(ENUM, RETURN, ARG1, ARG2, ARG3) \
3313   def_fn_type (ENUM, RETURN, 0, 3, ARG1, ARG2, ARG3);
3314 #define DEF_FUNCTION_TYPE_4(ENUM, RETURN, ARG1, ARG2, ARG3, ARG4) \
3315   def_fn_type (ENUM, RETURN, 0, 4, ARG1, ARG2, ARG3, ARG4);
3316 #define DEF_FUNCTION_TYPE_5(ENUM, RETURN, ARG1, ARG2, ARG3, ARG4, ARG5) \
3317   def_fn_type (ENUM, RETURN, 0, 5, ARG1, ARG2, ARG3, ARG4, ARG5);
3318 #define DEF_FUNCTION_TYPE_6(ENUM, RETURN, ARG1, ARG2, ARG3, ARG4, ARG5, \
3319                             ARG6)                                       \
3320   def_fn_type (ENUM, RETURN, 0, 6, ARG1, ARG2, ARG3, ARG4, ARG5, ARG6);
3321 #define DEF_FUNCTION_TYPE_7(ENUM, RETURN, ARG1, ARG2, ARG3, ARG4, ARG5, \
3322                             ARG6, ARG7)                                 \
3323   def_fn_type (ENUM, RETURN, 0, 7, ARG1, ARG2, ARG3, ARG4, ARG5, ARG6, ARG7);
3324 #define DEF_FUNCTION_TYPE_VAR_0(ENUM, RETURN) \
3325   def_fn_type (ENUM, RETURN, 1, 0);
3326 #define DEF_FUNCTION_TYPE_VAR_1(ENUM, RETURN, ARG1) \
3327   def_fn_type (ENUM, RETURN, 1, 1, ARG1);
3328 #define DEF_FUNCTION_TYPE_VAR_2(ENUM, RETURN, ARG1, ARG2) \
3329   def_fn_type (ENUM, RETURN, 1, 2, ARG1, ARG2);
3330 #define DEF_FUNCTION_TYPE_VAR_3(ENUM, RETURN, ARG1, ARG2, ARG3) \
3331   def_fn_type (ENUM, RETURN, 1, 3, ARG1, ARG2, ARG3);
3332 #define DEF_FUNCTION_TYPE_VAR_4(ENUM, RETURN, ARG1, ARG2, ARG3, ARG4) \
3333   def_fn_type (ENUM, RETURN, 1, 4, ARG1, ARG2, ARG3, ARG4);
3334 #define DEF_FUNCTION_TYPE_VAR_5(ENUM, RETURN, ARG1, ARG2, ARG3, ARG4, ARG5) \
3335   def_fn_type (ENUM, RETURN, 1, 5, ARG1, ARG2, ARG3, ARG4, ARG5);
3336 #define DEF_POINTER_TYPE(ENUM, TYPE) \
3337   builtin_types[(int) ENUM] = build_pointer_type (builtin_types[(int) TYPE]);
3338
3339 #include "builtin-types.def"
3340
3341 #undef DEF_PRIMITIVE_TYPE
3342 #undef DEF_FUNCTION_TYPE_1
3343 #undef DEF_FUNCTION_TYPE_2
3344 #undef DEF_FUNCTION_TYPE_3
3345 #undef DEF_FUNCTION_TYPE_4
3346 #undef DEF_FUNCTION_TYPE_5
3347 #undef DEF_FUNCTION_TYPE_6
3348 #undef DEF_FUNCTION_TYPE_VAR_0
3349 #undef DEF_FUNCTION_TYPE_VAR_1
3350 #undef DEF_FUNCTION_TYPE_VAR_2
3351 #undef DEF_FUNCTION_TYPE_VAR_3
3352 #undef DEF_FUNCTION_TYPE_VAR_4
3353 #undef DEF_FUNCTION_TYPE_VAR_5
3354 #undef DEF_POINTER_TYPE
3355   builtin_types[(int) BT_LAST] = NULL_TREE;
3356
3357   c_init_attributes ();
3358
3359 #define DEF_BUILTIN(ENUM, NAME, CLASS, TYPE, LIBTYPE, BOTH_P, FALLBACK_P, \
3360                     NONANSI_P, ATTRS, IMPLICIT, COND)                   \
3361   if (NAME && COND)                                                     \
3362     def_builtin_1 (ENUM, NAME, CLASS,                                   \
3363                    builtin_types[(int) TYPE],                           \
3364                    builtin_types[(int) LIBTYPE],                        \
3365                    BOTH_P, FALLBACK_P, NONANSI_P,                       \
3366                    built_in_attributes[(int) ATTRS], IMPLICIT);
3367 #include "builtins.def"
3368 #undef DEF_BUILTIN
3369
3370   build_common_builtin_nodes ();
3371
3372   targetm.init_builtins ();
3373   if (flag_mudflap)
3374     mudflap_init ();
3375
3376   main_identifier_node = get_identifier ("main");
3377
3378   /* Create the built-in __null node.  It is important that this is
3379      not shared.  */
3380   null_node = make_node (INTEGER_CST);
3381   TREE_TYPE (null_node) = c_common_type_for_size (POINTER_SIZE, 0);
3382
3383   /* Since builtin_types isn't gc'ed, don't export these nodes.  */
3384   memset (builtin_types, 0, sizeof (builtin_types));
3385 }
3386
3387 /* Look up the function in built_in_decls that corresponds to DECL
3388    and set ASMSPEC as its user assembler name.  DECL must be a
3389    function decl that declares a builtin.  */
3390
3391 void
3392 set_builtin_user_assembler_name (tree decl, const char *asmspec)
3393 {
3394   tree builtin;
3395   gcc_assert (TREE_CODE (decl) == FUNCTION_DECL
3396               && DECL_BUILT_IN_CLASS (decl) == BUILT_IN_NORMAL
3397               && asmspec != 0);
3398
3399   builtin = built_in_decls [DECL_FUNCTION_CODE (decl)];
3400   set_user_assembler_name (builtin, asmspec);
3401   if (DECL_FUNCTION_CODE (decl) == BUILT_IN_MEMCPY)
3402     init_block_move_fn (asmspec);
3403   else if (DECL_FUNCTION_CODE (decl) == BUILT_IN_MEMSET)
3404     init_block_clear_fn (asmspec);
3405 }
3406
3407 /* The number of named compound-literals generated thus far.  */
3408 static GTY(()) int compound_literal_number;
3409
3410 /* Set DECL_NAME for DECL, a VAR_DECL for a compound-literal.  */
3411
3412 void
3413 set_compound_literal_name (tree decl)
3414 {
3415   char *name;
3416   ASM_FORMAT_PRIVATE_NAME (name, "__compound_literal",
3417                            compound_literal_number);
3418   compound_literal_number++;
3419   DECL_NAME (decl) = get_identifier (name);
3420 }
3421
3422 tree
3423 build_va_arg (tree expr, tree type)
3424 {
3425   return build1 (VA_ARG_EXPR, type, expr);
3426 }
3427
3428
3429 /* Linked list of disabled built-in functions.  */
3430
3431 typedef struct disabled_builtin
3432 {
3433   const char *name;
3434   struct disabled_builtin *next;
3435 } disabled_builtin;
3436 static disabled_builtin *disabled_builtins = NULL;
3437
3438 static bool builtin_function_disabled_p (const char *);
3439
3440 /* Disable a built-in function specified by -fno-builtin-NAME.  If NAME
3441    begins with "__builtin_", give an error.  */
3442
3443 void
3444 disable_builtin_function (const char *name)
3445 {
3446   if (strncmp (name, "__builtin_", strlen ("__builtin_")) == 0)
3447     error ("cannot disable built-in function %qs", name);
3448   else
3449     {
3450       disabled_builtin *new_disabled_builtin = XNEW (disabled_builtin);
3451       new_disabled_builtin->name = name;
3452       new_disabled_builtin->next = disabled_builtins;
3453       disabled_builtins = new_disabled_builtin;
3454     }
3455 }
3456
3457
3458 /* Return true if the built-in function NAME has been disabled, false
3459    otherwise.  */
3460
3461 static bool
3462 builtin_function_disabled_p (const char *name)
3463 {
3464   disabled_builtin *p;
3465   for (p = disabled_builtins; p != NULL; p = p->next)
3466     {
3467       if (strcmp (name, p->name) == 0)
3468         return true;
3469     }
3470   return false;
3471 }
3472
3473
3474 /* Worker for DEF_BUILTIN.
3475    Possibly define a builtin function with one or two names.
3476    Does not declare a non-__builtin_ function if flag_no_builtin, or if
3477    nonansi_p and flag_no_nonansi_builtin.  */
3478
3479 static void
3480 def_builtin_1 (enum built_in_function fncode,
3481                const char *name,
3482                enum built_in_class fnclass,
3483                tree fntype, tree libtype,
3484                bool both_p, bool fallback_p, bool nonansi_p,
3485                tree fnattrs, bool implicit_p)
3486 {
3487   tree decl;
3488   const char *libname;
3489
3490   if (fntype == error_mark_node)
3491     return;
3492
3493   gcc_assert ((!both_p && !fallback_p)
3494               || !strncmp (name, "__builtin_",
3495                            strlen ("__builtin_")));
3496
3497   libname = name + strlen ("__builtin_");
3498   decl = lang_hooks.builtin_function (name, fntype, fncode, fnclass,
3499                                       (fallback_p ? libname : NULL),
3500                                       fnattrs);
3501   if (both_p
3502       && !flag_no_builtin && !builtin_function_disabled_p (libname)
3503       && !(nonansi_p && flag_no_nonansi_builtin))
3504     lang_hooks.builtin_function (libname, libtype, fncode, fnclass,
3505                                  NULL, fnattrs);
3506
3507   built_in_decls[(int) fncode] = decl;
3508   if (implicit_p)
3509     implicit_built_in_decls[(int) fncode] = decl;
3510 }
3511 \f
3512 /* Nonzero if the type T promotes to int.  This is (nearly) the
3513    integral promotions defined in ISO C99 6.3.1.1/2.  */
3514
3515 bool
3516 c_promoting_integer_type_p (tree t)
3517 {
3518   switch (TREE_CODE (t))
3519     {
3520     case INTEGER_TYPE:
3521       return (TYPE_MAIN_VARIANT (t) == char_type_node
3522               || TYPE_MAIN_VARIANT (t) == signed_char_type_node
3523               || TYPE_MAIN_VARIANT (t) == unsigned_char_type_node
3524               || TYPE_MAIN_VARIANT (t) == short_integer_type_node
3525               || TYPE_MAIN_VARIANT (t) == short_unsigned_type_node
3526               || TYPE_PRECISION (t) < TYPE_PRECISION (integer_type_node));
3527
3528     case ENUMERAL_TYPE:
3529       /* ??? Technically all enumerations not larger than an int
3530          promote to an int.  But this is used along code paths
3531          that only want to notice a size change.  */
3532       return TYPE_PRECISION (t) < TYPE_PRECISION (integer_type_node);
3533
3534     case BOOLEAN_TYPE:
3535       return 1;
3536
3537     default:
3538       return 0;
3539     }
3540 }
3541
3542 /* Return 1 if PARMS specifies a fixed number of parameters
3543    and none of their types is affected by default promotions.  */
3544
3545 int
3546 self_promoting_args_p (tree parms)
3547 {
3548   tree t;
3549   for (t = parms; t; t = TREE_CHAIN (t))
3550     {
3551       tree type = TREE_VALUE (t);
3552
3553       if (type == error_mark_node)
3554         continue;
3555
3556       if (TREE_CHAIN (t) == 0 && type != void_type_node)
3557         return 0;
3558
3559       if (type == 0)
3560         return 0;
3561
3562       if (TYPE_MAIN_VARIANT (type) == float_type_node)
3563         return 0;
3564
3565       if (c_promoting_integer_type_p (type))
3566         return 0;
3567     }
3568   return 1;
3569 }
3570
3571 /* Recursively examines the array elements of TYPE, until a non-array
3572    element type is found.  */
3573
3574 tree
3575 strip_array_types (tree type)
3576 {
3577   while (TREE_CODE (type) == ARRAY_TYPE)
3578     type = TREE_TYPE (type);
3579
3580   return type;
3581 }
3582
3583 /* Recursively remove any '*' or '&' operator from TYPE.  */
3584 tree
3585 strip_pointer_operator (tree t)
3586 {
3587   while (POINTER_TYPE_P (t))
3588     t = TREE_TYPE (t);
3589   return t;
3590 }
3591
3592 /* Used to compare case labels.  K1 and K2 are actually tree nodes
3593    representing case labels, or NULL_TREE for a `default' label.
3594    Returns -1 if K1 is ordered before K2, -1 if K1 is ordered after
3595    K2, and 0 if K1 and K2 are equal.  */
3596
3597 int
3598 case_compare (splay_tree_key k1, splay_tree_key k2)
3599 {
3600   /* Consider a NULL key (such as arises with a `default' label) to be
3601      smaller than anything else.  */
3602   if (!k1)
3603     return k2 ? -1 : 0;
3604   else if (!k2)
3605     return k1 ? 1 : 0;
3606
3607   return tree_int_cst_compare ((tree) k1, (tree) k2);
3608 }
3609
3610 /* Process a case label for the range LOW_VALUE ... HIGH_VALUE.  If
3611    LOW_VALUE and HIGH_VALUE are both NULL_TREE then this case label is
3612    actually a `default' label.  If only HIGH_VALUE is NULL_TREE, then
3613    case label was declared using the usual C/C++ syntax, rather than
3614    the GNU case range extension.  CASES is a tree containing all the
3615    case ranges processed so far; COND is the condition for the
3616    switch-statement itself.  Returns the CASE_LABEL_EXPR created, or
3617    ERROR_MARK_NODE if no CASE_LABEL_EXPR is created.  */
3618
3619 tree
3620 c_add_case_label (splay_tree cases, tree cond, tree orig_type,
3621                   tree low_value, tree high_value)
3622 {
3623   tree type;
3624   tree label;
3625   tree case_label;
3626   splay_tree_node node;
3627
3628   /* Create the LABEL_DECL itself.  */
3629   label = create_artificial_label ();
3630
3631   /* If there was an error processing the switch condition, bail now
3632      before we get more confused.  */
3633   if (!cond || cond == error_mark_node)
3634     goto error_out;
3635
3636   if ((low_value && TREE_TYPE (low_value)
3637        && POINTER_TYPE_P (TREE_TYPE (low_value)))
3638       || (high_value && TREE_TYPE (high_value)
3639           && POINTER_TYPE_P (TREE_TYPE (high_value))))
3640     {
3641       error ("pointers are not permitted as case values");
3642       goto error_out;
3643     }
3644
3645   /* Case ranges are a GNU extension.  */
3646   if (high_value && pedantic)
3647     pedwarn ("range expressions in switch statements are non-standard");
3648
3649   type = TREE_TYPE (cond);
3650   if (low_value)
3651     {
3652       low_value = check_case_value (low_value);
3653       low_value = convert_and_check (type, low_value);
3654       if (low_value == error_mark_node)
3655         goto error_out;
3656     }
3657   if (high_value)
3658     {
3659       high_value = check_case_value (high_value);
3660       high_value = convert_and_check (type, high_value);
3661       if (high_value == error_mark_node)
3662         goto error_out;
3663     }
3664
3665   if (low_value && high_value)
3666     {
3667       /* If the LOW_VALUE and HIGH_VALUE are the same, then this isn't
3668          really a case range, even though it was written that way.
3669          Remove the HIGH_VALUE to simplify later processing.  */
3670       if (tree_int_cst_equal (low_value, high_value))
3671         high_value = NULL_TREE;
3672       else if (!tree_int_cst_lt (low_value, high_value))
3673         warning (0, "empty range specified");
3674     }
3675
3676   /* See if the case is in range of the type of the original testing
3677      expression.  If both low_value and high_value are out of range,
3678      don't insert the case label and return NULL_TREE.  */
3679   if (low_value
3680       && !check_case_bounds (type, orig_type,
3681                              &low_value, high_value ? &high_value : NULL))
3682     return NULL_TREE;
3683
3684   /* Look up the LOW_VALUE in the table of case labels we already
3685      have.  */
3686   node = splay_tree_lookup (cases, (splay_tree_key) low_value);
3687   /* If there was not an exact match, check for overlapping ranges.
3688      There's no need to do this if there's no LOW_VALUE or HIGH_VALUE;
3689      that's a `default' label and the only overlap is an exact match.  */
3690   if (!node && (low_value || high_value))
3691     {
3692       splay_tree_node low_bound;
3693       splay_tree_node high_bound;
3694
3695       /* Even though there wasn't an exact match, there might be an
3696          overlap between this case range and another case range.
3697          Since we've (inductively) not allowed any overlapping case
3698          ranges, we simply need to find the greatest low case label
3699          that is smaller that LOW_VALUE, and the smallest low case
3700          label that is greater than LOW_VALUE.  If there is an overlap
3701          it will occur in one of these two ranges.  */
3702       low_bound = splay_tree_predecessor (cases,
3703                                           (splay_tree_key) low_value);
3704       high_bound = splay_tree_successor (cases,
3705                                          (splay_tree_key) low_value);
3706
3707       /* Check to see if the LOW_BOUND overlaps.  It is smaller than
3708          the LOW_VALUE, so there is no need to check unless the
3709          LOW_BOUND is in fact itself a case range.  */
3710       if (low_bound
3711           && CASE_HIGH ((tree) low_bound->value)
3712           && tree_int_cst_compare (CASE_HIGH ((tree) low_bound->value),
3713                                     low_value) >= 0)
3714         node = low_bound;
3715       /* Check to see if the HIGH_BOUND overlaps.  The low end of that
3716          range is bigger than the low end of the current range, so we
3717          are only interested if the current range is a real range, and
3718          not an ordinary case label.  */
3719       else if (high_bound
3720                && high_value
3721                && (tree_int_cst_compare ((tree) high_bound->key,
3722                                          high_value)
3723                    <= 0))
3724         node = high_bound;
3725     }
3726   /* If there was an overlap, issue an error.  */
3727   if (node)
3728     {
3729       tree duplicate = CASE_LABEL ((tree) node->value);
3730
3731       if (high_value)
3732         {
3733           error ("duplicate (or overlapping) case value");
3734           error ("%Jthis is the first entry overlapping that value", duplicate);
3735         }
3736       else if (low_value)
3737         {
3738           error ("duplicate case value") ;
3739           error ("%Jpreviously used here", duplicate);
3740         }
3741       else
3742         {
3743           error ("multiple default labels in one switch");
3744           error ("%Jthis is the first default label", duplicate);
3745         }
3746       goto error_out;
3747     }
3748
3749   /* Add a CASE_LABEL to the statement-tree.  */
3750   case_label = add_stmt (build_case_label (low_value, high_value, label));
3751   /* Register this case label in the splay tree.  */
3752   splay_tree_insert (cases,
3753                      (splay_tree_key) low_value,
3754                      (splay_tree_value) case_label);
3755
3756   return case_label;
3757
3758  error_out:
3759   /* Add a label so that the back-end doesn't think that the beginning of
3760      the switch is unreachable.  Note that we do not add a case label, as
3761      that just leads to duplicates and thence to failure later on.  */
3762   if (!cases->root)
3763     {
3764       tree t = create_artificial_label ();
3765       add_stmt (build_stmt (LABEL_EXPR, t));
3766     }
3767   return error_mark_node;
3768 }
3769
3770 /* Subroutines of c_do_switch_warnings, called via splay_tree_foreach.
3771    Used to verify that case values match up with enumerator values.  */
3772
3773 static void
3774 match_case_to_enum_1 (tree key, tree type, tree label)
3775 {
3776   char buf[2 + 2*HOST_BITS_PER_WIDE_INT/4 + 1];
3777
3778   /* ??? Not working too hard to print the double-word value.
3779      Should perhaps be done with %lwd in the diagnostic routines?  */
3780   if (TREE_INT_CST_HIGH (key) == 0)
3781     snprintf (buf, sizeof (buf), HOST_WIDE_INT_PRINT_UNSIGNED,
3782               TREE_INT_CST_LOW (key));
3783   else if (!TYPE_UNSIGNED (type)
3784            && TREE_INT_CST_HIGH (key) == -1
3785            && TREE_INT_CST_LOW (key) != 0)
3786     snprintf (buf, sizeof (buf), "-" HOST_WIDE_INT_PRINT_UNSIGNED,
3787               -TREE_INT_CST_LOW (key));
3788   else
3789     snprintf (buf, sizeof (buf), HOST_WIDE_INT_PRINT_DOUBLE_HEX,
3790               TREE_INT_CST_HIGH (key), TREE_INT_CST_LOW (key));
3791
3792   if (TYPE_NAME (type) == 0)
3793     warning (0, "%Jcase value %qs not in enumerated type",
3794              CASE_LABEL (label), buf);
3795   else
3796     warning (0, "%Jcase value %qs not in enumerated type %qT",
3797              CASE_LABEL (label), buf, type);
3798 }
3799
3800 /* Subroutine of c_do_switch_warnings, called via splay_tree_foreach.
3801    Used to verify that case values match up with enumerator values.  */
3802
3803 static int
3804 match_case_to_enum (splay_tree_node node, void *data)
3805 {
3806   tree label = (tree) node->value;
3807   tree type = (tree) data;
3808
3809   /* Skip default case.  */
3810   if (!CASE_LOW (label))
3811     return 0;
3812
3813   /* If CASE_LOW_SEEN is not set, that means CASE_LOW did not appear
3814      when we did our enum->case scan.  Reset our scratch bit after.  */
3815   if (!CASE_LOW_SEEN (label))
3816     match_case_to_enum_1 (CASE_LOW (label), type, label);
3817   else
3818     CASE_LOW_SEEN (label) = 0;
3819
3820   /* If CASE_HIGH is non-null, we have a range.  If CASE_HIGH_SEEN is
3821      not set, that means that CASE_HIGH did not appear when we did our
3822      enum->case scan.  Reset our scratch bit after.  */
3823   if (CASE_HIGH (label))
3824     {
3825       if (!CASE_HIGH_SEEN (label))
3826         match_case_to_enum_1 (CASE_HIGH (label), type, label);
3827       else
3828         CASE_HIGH_SEEN (label) = 0;
3829     }
3830
3831   return 0;
3832 }
3833
3834 /* Handle -Wswitch*.  Called from the front end after parsing the
3835    switch construct.  */
3836 /* ??? Should probably be somewhere generic, since other languages
3837    besides C and C++ would want this.  At the moment, however, C/C++
3838    are the only tree-ssa languages that support enumerations at all,
3839    so the point is moot.  */
3840
3841 void
3842 c_do_switch_warnings (splay_tree cases, location_t switch_location,
3843                       tree type, tree cond)
3844 {
3845   splay_tree_node default_node;
3846   splay_tree_node node;
3847   tree chain;
3848
3849   if (!warn_switch && !warn_switch_enum && !warn_switch_default)
3850     return;
3851
3852   default_node = splay_tree_lookup (cases, (splay_tree_key) NULL);
3853   if (!default_node)
3854     warning (OPT_Wswitch_default, "%Hswitch missing default case",
3855              &switch_location);
3856
3857   /* From here on, we only care about about enumerated types.  */
3858   if (!type || TREE_CODE (type) != ENUMERAL_TYPE)
3859     return;
3860
3861   /* If the switch expression was an enumerated type, check that
3862      exactly all enumeration literals are covered by the cases.
3863      The check is made when -Wswitch was specified and there is no
3864      default case, or when -Wswitch-enum was specified.  */
3865
3866   if (!warn_switch_enum
3867       && !(warn_switch && !default_node))
3868     return;
3869
3870   /* Clearing COND if it is not an integer constant simplifies
3871      the tests inside the loop below.  */
3872   if (TREE_CODE (cond) != INTEGER_CST)
3873     cond = NULL_TREE;
3874
3875   /* The time complexity here is O(N*lg(N)) worst case, but for the
3876       common case of monotonically increasing enumerators, it is
3877       O(N), since the nature of the splay tree will keep the next
3878       element adjacent to the root at all times.  */
3879
3880   for (chain = TYPE_VALUES (type); chain; chain = TREE_CHAIN (chain))
3881     {
3882       tree value = TREE_VALUE (chain);
3883       node = splay_tree_lookup (cases, (splay_tree_key) value);
3884       if (node)
3885         {
3886           /* Mark the CASE_LOW part of the case entry as seen.  */
3887           tree label = (tree) node->value;
3888           CASE_LOW_SEEN (label) = 1;
3889           continue;
3890         }
3891
3892       /* Even though there wasn't an exact match, there might be a
3893          case range which includes the enumator's value.  */
3894       node = splay_tree_predecessor (cases, (splay_tree_key) value);
3895       if (node && CASE_HIGH ((tree) node->value))
3896         {
3897           tree label = (tree) node->value;
3898           int cmp = tree_int_cst_compare (CASE_HIGH (label), value);
3899           if (cmp >= 0)
3900             {
3901               /* If we match the upper bound exactly, mark the CASE_HIGH
3902                  part of the case entry as seen.  */
3903               if (cmp == 0)
3904                 CASE_HIGH_SEEN (label) = 1;
3905               continue;
3906             }
3907         }
3908
3909       /* We've now determined that this enumerated literal isn't
3910          handled by the case labels of the switch statement.  */
3911
3912       /* If the switch expression is a constant, we only really care
3913          about whether that constant is handled by the switch.  */
3914       if (cond && tree_int_cst_compare (cond, value))
3915         continue;
3916
3917       warning (0, "%Henumeration value %qE not handled in switch",
3918                &switch_location, TREE_PURPOSE (chain));
3919     }
3920
3921   /* Warn if there are case expressions that don't correspond to
3922      enumerators.  This can occur since C and C++ don't enforce
3923      type-checking of assignments to enumeration variables.
3924
3925      The time complexity here is now always O(N) worst case, since
3926      we should have marked both the lower bound and upper bound of
3927      every disjoint case label, with CASE_LOW_SEEN and CASE_HIGH_SEEN
3928      above.  This scan also resets those fields.  */
3929   splay_tree_foreach (cases, match_case_to_enum, type);
3930 }
3931
3932 /* Finish an expression taking the address of LABEL (an
3933    IDENTIFIER_NODE).  Returns an expression for the address.  */
3934
3935 tree
3936 finish_label_address_expr (tree label)
3937 {
3938   tree result;
3939
3940   if (pedantic)
3941     pedwarn ("taking the address of a label is non-standard");
3942
3943   if (label == error_mark_node)
3944     return error_mark_node;
3945
3946   label = lookup_label (label);
3947   if (label == NULL_TREE)
3948     result = null_pointer_node;
3949   else
3950     {
3951       TREE_USED (label) = 1;
3952       result = build1 (ADDR_EXPR, ptr_type_node, label);
3953       /* The current function in not necessarily uninlinable.
3954          Computed gotos are incompatible with inlining, but the value
3955          here could be used only in a diagnostic, for example.  */
3956     }
3957
3958   return result;
3959 }
3960
3961 /* Hook used by expand_expr to expand language-specific tree codes.  */
3962 /* The only things that should go here are bits needed to expand
3963    constant initializers.  Everything else should be handled by the
3964    gimplification routines.  */
3965
3966 rtx
3967 c_expand_expr (tree exp, rtx target, enum machine_mode tmode,
3968                int modifier /* Actually enum_modifier.  */,
3969                rtx *alt_rtl)
3970 {
3971   switch (TREE_CODE (exp))
3972     {
3973     case COMPOUND_LITERAL_EXPR:
3974       {
3975         /* Initialize the anonymous variable declared in the compound
3976            literal, then return the variable.  */
3977         tree decl = COMPOUND_LITERAL_EXPR_DECL (exp);
3978         emit_local_var (decl);
3979         return expand_expr_real (decl, target, tmode, modifier, alt_rtl);
3980       }
3981
3982     default:
3983       gcc_unreachable ();
3984     }
3985 }
3986
3987 /* Hook used by staticp to handle language-specific tree codes.  */
3988
3989 tree
3990 c_staticp (tree exp)
3991 {
3992   return (TREE_CODE (exp) == COMPOUND_LITERAL_EXPR
3993           && TREE_STATIC (COMPOUND_LITERAL_EXPR_DECL (exp))
3994           ? exp : NULL);
3995 }
3996 \f
3997
3998 /* Given a boolean expression ARG, return a tree representing an increment
3999    or decrement (as indicated by CODE) of ARG.  The front end must check for
4000    invalid cases (e.g., decrement in C++).  */
4001 tree
4002 boolean_increment (enum tree_code code, tree arg)
4003 {
4004   tree val;
4005   tree true_res = boolean_true_node;
4006
4007   arg = stabilize_reference (arg);
4008   switch (code)
4009     {
4010     case PREINCREMENT_EXPR:
4011       val = build2 (MODIFY_EXPR, TREE_TYPE (arg), arg, true_res);
4012       break;
4013     case POSTINCREMENT_EXPR:
4014       val = build2 (MODIFY_EXPR, TREE_TYPE (arg), arg, true_res);
4015       arg = save_expr (arg);
4016       val = build2 (COMPOUND_EXPR, TREE_TYPE (arg), val, arg);
4017       val = build2 (COMPOUND_EXPR, TREE_TYPE (arg), arg, val);
4018       break;
4019     case PREDECREMENT_EXPR:
4020       val = build2 (MODIFY_EXPR, TREE_TYPE (arg), arg,
4021                     invert_truthvalue (arg));
4022       break;
4023     case POSTDECREMENT_EXPR:
4024       val = build2 (MODIFY_EXPR, TREE_TYPE (arg), arg,
4025                     invert_truthvalue (arg));
4026       arg = save_expr (arg);
4027       val = build2 (COMPOUND_EXPR, TREE_TYPE (arg), val, arg);
4028       val = build2 (COMPOUND_EXPR, TREE_TYPE (arg), arg, val);
4029       break;
4030     default:
4031       gcc_unreachable ();
4032     }
4033   TREE_SIDE_EFFECTS (val) = 1;
4034   return val;
4035 }
4036 \f
4037 /* Built-in macros for stddef.h, that require macros defined in this
4038    file.  */
4039 void
4040 c_stddef_cpp_builtins(void)
4041 {
4042   builtin_define_with_value ("__SIZE_TYPE__", SIZE_TYPE, 0);
4043   builtin_define_with_value ("__PTRDIFF_TYPE__", PTRDIFF_TYPE, 0);
4044   builtin_define_with_value ("__WCHAR_TYPE__", MODIFIED_WCHAR_TYPE, 0);
4045   builtin_define_with_value ("__WINT_TYPE__", WINT_TYPE, 0);
4046   builtin_define_with_value ("__INTMAX_TYPE__", INTMAX_TYPE, 0);
4047   builtin_define_with_value ("__UINTMAX_TYPE__", UINTMAX_TYPE, 0);
4048 }
4049
4050 static void
4051 c_init_attributes (void)
4052 {
4053   /* Fill in the built_in_attributes array.  */
4054 #define DEF_ATTR_NULL_TREE(ENUM)                                \
4055   built_in_attributes[(int) ENUM] = NULL_TREE;
4056 #define DEF_ATTR_INT(ENUM, VALUE)                               \
4057   built_in_attributes[(int) ENUM] = build_int_cst (NULL_TREE, VALUE);
4058 #define DEF_ATTR_IDENT(ENUM, STRING)                            \
4059   built_in_attributes[(int) ENUM] = get_identifier (STRING);
4060 #define DEF_ATTR_TREE_LIST(ENUM, PURPOSE, VALUE, CHAIN) \
4061   built_in_attributes[(int) ENUM]                       \
4062     = tree_cons (built_in_attributes[(int) PURPOSE],    \
4063                  built_in_attributes[(int) VALUE],      \
4064                  built_in_attributes[(int) CHAIN]);
4065 #include "builtin-attrs.def"
4066 #undef DEF_ATTR_NULL_TREE
4067 #undef DEF_ATTR_INT
4068 #undef DEF_ATTR_IDENT
4069 #undef DEF_ATTR_TREE_LIST
4070 }
4071
4072 /* Attribute handlers common to C front ends.  */
4073
4074 /* Handle a "packed" attribute; arguments as in
4075    struct attribute_spec.handler.  */
4076
4077 static tree
4078 handle_packed_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4079                          int flags, bool *no_add_attrs)
4080 {
4081   if (TYPE_P (*node))
4082     {
4083       if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
4084         *node = build_variant_type_copy (*node);
4085       TYPE_PACKED (*node) = 1;
4086     }
4087   else if (TREE_CODE (*node) == FIELD_DECL)
4088     {
4089       if (TYPE_ALIGN (TREE_TYPE (*node)) <= BITS_PER_UNIT)
4090         warning (OPT_Wattributes,
4091                  "%qE attribute ignored for field of type %qT",
4092                  name, TREE_TYPE (*node));
4093       else
4094         DECL_PACKED (*node) = 1;
4095     }
4096   /* We can't set DECL_PACKED for a VAR_DECL, because the bit is
4097      used for DECL_REGISTER.  It wouldn't mean anything anyway.
4098      We can't set DECL_PACKED on the type of a TYPE_DECL, because
4099      that changes what the typedef is typing.  */
4100   else
4101     {
4102       warning (OPT_Wattributes, "%qE attribute ignored", name);
4103       *no_add_attrs = true;
4104     }
4105
4106   return NULL_TREE;
4107 }
4108
4109 /* Handle a "nocommon" attribute; arguments as in
4110    struct attribute_spec.handler.  */
4111
4112 static tree
4113 handle_nocommon_attribute (tree *node, tree name,
4114                            tree ARG_UNUSED (args),
4115                            int ARG_UNUSED (flags), bool *no_add_attrs)
4116 {
4117   if (TREE_CODE (*node) == VAR_DECL)
4118     DECL_COMMON (*node) = 0;
4119   else
4120     {
4121       warning (OPT_Wattributes, "%qE attribute ignored", name);
4122       *no_add_attrs = true;
4123     }
4124
4125   return NULL_TREE;
4126 }
4127
4128 /* Handle a "common" attribute; arguments as in
4129    struct attribute_spec.handler.  */
4130
4131 static tree
4132 handle_common_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4133                          int ARG_UNUSED (flags), bool *no_add_attrs)
4134 {
4135   if (TREE_CODE (*node) == VAR_DECL)
4136     DECL_COMMON (*node) = 1;
4137   else
4138     {
4139       warning (OPT_Wattributes, "%qE attribute ignored", name);
4140       *no_add_attrs = true;
4141     }
4142
4143   return NULL_TREE;
4144 }
4145
4146 /* Handle a "noreturn" attribute; arguments as in
4147    struct attribute_spec.handler.  */
4148
4149 static tree
4150 handle_noreturn_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4151                            int ARG_UNUSED (flags), bool *no_add_attrs)
4152 {
4153   tree type = TREE_TYPE (*node);
4154
4155   /* See FIXME comment in c_common_attribute_table.  */
4156   if (TREE_CODE (*node) == FUNCTION_DECL)
4157     TREE_THIS_VOLATILE (*node) = 1;
4158   else if (TREE_CODE (type) == POINTER_TYPE
4159            && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE)
4160     TREE_TYPE (*node)
4161       = build_pointer_type
4162         (build_type_variant (TREE_TYPE (type),
4163                              TYPE_READONLY (TREE_TYPE (type)), 1));
4164   else
4165     {
4166       warning (OPT_Wattributes, "%qE attribute ignored", name);
4167       *no_add_attrs = true;
4168     }
4169
4170   return NULL_TREE;
4171 }
4172
4173 /* Handle a "noinline" attribute; arguments as in
4174    struct attribute_spec.handler.  */
4175
4176 static tree
4177 handle_noinline_attribute (tree *node, tree name,
4178                            tree ARG_UNUSED (args),
4179                            int ARG_UNUSED (flags), bool *no_add_attrs)
4180 {
4181   if (TREE_CODE (*node) == FUNCTION_DECL)
4182     DECL_UNINLINABLE (*node) = 1;
4183   else
4184     {
4185       warning (OPT_Wattributes, "%qE attribute ignored", name);
4186       *no_add_attrs = true;
4187     }
4188
4189   return NULL_TREE;
4190 }
4191
4192 /* Handle a "always_inline" attribute; arguments as in
4193    struct attribute_spec.handler.  */
4194
4195 static tree
4196 handle_always_inline_attribute (tree *node, tree name,
4197                                 tree ARG_UNUSED (args),
4198                                 int ARG_UNUSED (flags),
4199                                 bool *no_add_attrs)
4200 {
4201   if (TREE_CODE (*node) == FUNCTION_DECL)
4202     {
4203       /* Do nothing else, just set the attribute.  We'll get at
4204          it later with lookup_attribute.  */
4205     }
4206   else
4207     {
4208       warning (OPT_Wattributes, "%qE attribute ignored", name);
4209       *no_add_attrs = true;
4210     }
4211
4212   return NULL_TREE;
4213 }
4214
4215 /* Handle a "flatten" attribute; arguments as in
4216    struct attribute_spec.handler.  */
4217
4218 static tree
4219 handle_flatten_attribute (tree *node, tree name,
4220                           tree args ATTRIBUTE_UNUSED,
4221                           int flags ATTRIBUTE_UNUSED, bool *no_add_attrs)
4222 {
4223   if (TREE_CODE (*node) == FUNCTION_DECL)
4224     /* Do nothing else, just set the attribute.  We'll get at
4225        it later with lookup_attribute.  */
4226     ;
4227   else
4228     {
4229       warning (OPT_Wattributes, "%qE attribute ignored", name);
4230       *no_add_attrs = true;
4231     }
4232
4233   return NULL_TREE;
4234 }
4235
4236
4237 /* Handle a "used" attribute; arguments as in
4238    struct attribute_spec.handler.  */
4239
4240 static tree
4241 handle_used_attribute (tree *pnode, tree name, tree ARG_UNUSED (args),
4242                        int ARG_UNUSED (flags), bool *no_add_attrs)
4243 {
4244   tree node = *pnode;
4245
4246   if (TREE_CODE (node) == FUNCTION_DECL
4247       || (TREE_CODE (node) == VAR_DECL && TREE_STATIC (node)))
4248     {
4249       TREE_USED (node) = 1;
4250       DECL_PRESERVE_P (node) = 1;
4251     }
4252   else
4253     {
4254       warning (OPT_Wattributes, "%qE attribute ignored", name);
4255       *no_add_attrs = true;
4256     }
4257
4258   return NULL_TREE;
4259 }
4260
4261 /* Handle a "unused" attribute; arguments as in
4262    struct attribute_spec.handler.  */
4263
4264 static tree
4265 handle_unused_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4266                          int flags, bool *no_add_attrs)
4267 {
4268   if (DECL_P (*node))
4269     {
4270       tree decl = *node;
4271
4272       if (TREE_CODE (decl) == PARM_DECL
4273           || TREE_CODE (decl) == VAR_DECL
4274           || TREE_CODE (decl) == FUNCTION_DECL
4275           || TREE_CODE (decl) == LABEL_DECL
4276           || TREE_CODE (decl) == TYPE_DECL)
4277         TREE_USED (decl) = 1;
4278       else
4279         {
4280           warning (OPT_Wattributes, "%qE attribute ignored", name);
4281           *no_add_attrs = true;
4282         }
4283     }
4284   else
4285     {
4286       if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
4287         *node = build_variant_type_copy (*node);
4288       TREE_USED (*node) = 1;
4289     }
4290
4291   return NULL_TREE;
4292 }
4293
4294 /* Handle a "externally_visible" attribute; arguments as in
4295    struct attribute_spec.handler.  */
4296
4297 static tree
4298 handle_externally_visible_attribute (tree *pnode, tree name,
4299                                      tree ARG_UNUSED (args),
4300                                      int ARG_UNUSED (flags),
4301                                      bool *no_add_attrs)
4302 {
4303   tree node = *pnode;
4304
4305   if (TREE_CODE (node) == FUNCTION_DECL || TREE_CODE (node) == VAR_DECL)
4306     {
4307       if ((!TREE_STATIC (node) && TREE_CODE (node) != FUNCTION_DECL
4308            && !DECL_EXTERNAL (node)) || !TREE_PUBLIC (node))
4309         {
4310           warning (OPT_Wattributes,
4311                    "%qE attribute have effect only on public objects", name);
4312           *no_add_attrs = true;
4313         }
4314     }
4315   else
4316     {
4317       warning (OPT_Wattributes, "%qE attribute ignored", name);
4318       *no_add_attrs = true;
4319     }
4320
4321   return NULL_TREE;
4322 }
4323
4324 /* Handle a "const" attribute; arguments as in
4325    struct attribute_spec.handler.  */
4326
4327 static tree
4328 handle_const_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4329                         int ARG_UNUSED (flags), bool *no_add_attrs)
4330 {
4331   tree type = TREE_TYPE (*node);
4332
4333   /* See FIXME comment on noreturn in c_common_attribute_table.  */
4334   if (TREE_CODE (*node) == FUNCTION_DECL)
4335     TREE_READONLY (*node) = 1;
4336   else if (TREE_CODE (type) == POINTER_TYPE
4337            && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE)
4338     TREE_TYPE (*node)
4339       = build_pointer_type
4340         (build_type_variant (TREE_TYPE (type), 1,
4341                              TREE_THIS_VOLATILE (TREE_TYPE (type))));
4342   else
4343     {
4344       warning (OPT_Wattributes, "%qE attribute ignored", name);
4345       *no_add_attrs = true;
4346     }
4347
4348   return NULL_TREE;
4349 }
4350
4351 /* Handle a "transparent_union" attribute; arguments as in
4352    struct attribute_spec.handler.  */
4353
4354 static tree
4355 handle_transparent_union_attribute (tree *node, tree name,
4356                                     tree ARG_UNUSED (args), int flags,
4357                                     bool *no_add_attrs)
4358 {
4359   tree type = NULL;
4360
4361   *no_add_attrs = true;
4362
4363   if (DECL_P (*node))
4364     {
4365       if (TREE_CODE (*node) != TYPE_DECL)
4366         goto ignored;
4367       node = &TREE_TYPE (*node);
4368       type = *node;
4369     }
4370   else if (TYPE_P (*node))
4371     type = *node;
4372   else
4373     goto ignored;
4374
4375   if (TREE_CODE (type) == UNION_TYPE)
4376     {
4377       /* When IN_PLACE is set, leave the check for FIELDS and MODE to
4378          the code in finish_struct.  */
4379       if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
4380         {
4381           if (TYPE_FIELDS (type) == NULL_TREE
4382               || TYPE_MODE (type) != DECL_MODE (TYPE_FIELDS (type)))
4383             goto ignored;
4384
4385           /* A type variant isn't good enough, since we don't a cast
4386              to such a type removed as a no-op.  */
4387           *node = type = build_duplicate_type (type);
4388         }
4389
4390       TYPE_TRANSPARENT_UNION (type) = 1;
4391       return NULL_TREE;
4392     }
4393
4394  ignored:
4395   warning (OPT_Wattributes, "%qE attribute ignored", name);
4396   return NULL_TREE;
4397 }
4398
4399 /* Handle a "constructor" attribute; arguments as in
4400    struct attribute_spec.handler.  */
4401
4402 static tree
4403 handle_constructor_attribute (tree *node, tree name,
4404                               tree ARG_UNUSED (args),
4405                               int ARG_UNUSED (flags),
4406                               bool *no_add_attrs)
4407 {
4408   tree decl = *node;
4409   tree type = TREE_TYPE (decl);
4410
4411   if (TREE_CODE (decl) == FUNCTION_DECL
4412       && TREE_CODE (type) == FUNCTION_TYPE
4413       && decl_function_context (decl) == 0)
4414     {
4415       DECL_STATIC_CONSTRUCTOR (decl) = 1;
4416       TREE_USED (decl) = 1;
4417     }
4418   else
4419     {
4420       warning (OPT_Wattributes, "%qE attribute ignored", name);
4421       *no_add_attrs = true;
4422     }
4423
4424   return NULL_TREE;
4425 }
4426
4427 /* Handle a "destructor" attribute; arguments as in
4428    struct attribute_spec.handler.  */
4429
4430 static tree
4431 handle_destructor_attribute (tree *node, tree name,
4432                              tree ARG_UNUSED (args),
4433                              int ARG_UNUSED (flags),
4434                              bool *no_add_attrs)
4435 {
4436   tree decl = *node;
4437   tree type = TREE_TYPE (decl);
4438
4439   if (TREE_CODE (decl) == FUNCTION_DECL
4440       && TREE_CODE (type) == FUNCTION_TYPE
4441       && decl_function_context (decl) == 0)
4442     {
4443       DECL_STATIC_DESTRUCTOR (decl) = 1;
4444       TREE_USED (decl) = 1;
4445     }
4446   else
4447     {
4448       warning (OPT_Wattributes, "%qE attribute ignored", name);
4449       *no_add_attrs = true;
4450     }
4451
4452   return NULL_TREE;
4453 }
4454
4455 /* Handle a "mode" attribute; arguments as in
4456    struct attribute_spec.handler.  */
4457
4458 static tree
4459 handle_mode_attribute (tree *node, tree name, tree args,
4460                        int ARG_UNUSED (flags), bool *no_add_attrs)
4461 {
4462   tree type = *node;
4463
4464   *no_add_attrs = true;
4465
4466   if (TREE_CODE (TREE_VALUE (args)) != IDENTIFIER_NODE)
4467     warning (OPT_Wattributes, "%qE attribute ignored", name);
4468   else
4469     {
4470       int j;
4471       const char *p = IDENTIFIER_POINTER (TREE_VALUE (args));
4472       int len = strlen (p);
4473       enum machine_mode mode = VOIDmode;
4474       tree typefm;
4475       bool valid_mode;
4476
4477       if (len > 4 && p[0] == '_' && p[1] == '_'
4478           && p[len - 1] == '_' && p[len - 2] == '_')
4479         {
4480           char *newp = (char *) alloca (len - 1);
4481
4482           strcpy (newp, &p[2]);
4483           newp[len - 4] = '\0';
4484           p = newp;
4485         }
4486
4487       /* Change this type to have a type with the specified mode.
4488          First check for the special modes.  */
4489       if (!strcmp (p, "byte"))
4490         mode = byte_mode;
4491       else if (!strcmp (p, "word"))
4492         mode = word_mode;
4493       else if (!strcmp (p, "pointer"))
4494         mode = ptr_mode;
4495       else
4496         for (j = 0; j < NUM_MACHINE_MODES; j++)
4497           if (!strcmp (p, GET_MODE_NAME (j)))
4498             {
4499               mode = (enum machine_mode) j;
4500               break;
4501             }
4502
4503       if (mode == VOIDmode)
4504         {
4505           error ("unknown machine mode %qs", p);
4506           return NULL_TREE;
4507         }
4508
4509       valid_mode = false;
4510       switch (GET_MODE_CLASS (mode))
4511         {
4512         case MODE_INT:
4513         case MODE_PARTIAL_INT:
4514         case MODE_FLOAT:
4515         case MODE_DECIMAL_FLOAT:
4516           valid_mode = targetm.scalar_mode_supported_p (mode);
4517           break;
4518
4519         case MODE_COMPLEX_INT:
4520         case MODE_COMPLEX_FLOAT:
4521           valid_mode = targetm.scalar_mode_supported_p (GET_MODE_INNER (mode));
4522           break;
4523
4524         case MODE_VECTOR_INT:
4525         case MODE_VECTOR_FLOAT:
4526           warning (OPT_Wattributes, "specifying vector types with "
4527                    "__attribute__ ((mode)) is deprecated");
4528           warning (OPT_Wattributes,
4529                    "use __attribute__ ((vector_size)) instead");
4530           valid_mode = vector_mode_valid_p (mode);
4531           break;
4532
4533         default:
4534           break;
4535         }
4536       if (!valid_mode)
4537         {
4538           error ("unable to emulate %qs", p);
4539           return NULL_TREE;
4540         }
4541
4542       if (POINTER_TYPE_P (type))
4543         {
4544           tree (*fn)(tree, enum machine_mode, bool);
4545
4546           if (!targetm.valid_pointer_mode (mode))
4547             {
4548               error ("invalid pointer mode %qs", p);
4549               return NULL_TREE;
4550             }
4551
4552           if (TREE_CODE (type) == POINTER_TYPE)
4553             fn = build_pointer_type_for_mode;
4554           else
4555             fn = build_reference_type_for_mode;
4556           typefm = fn (TREE_TYPE (type), mode, false);
4557         }
4558       else
4559         typefm = lang_hooks.types.type_for_mode (mode, TYPE_UNSIGNED (type));
4560
4561       if (typefm == NULL_TREE)
4562         {
4563           error ("no data type for mode %qs", p);
4564           return NULL_TREE;
4565         }
4566       else if (TREE_CODE (type) == ENUMERAL_TYPE)
4567         {
4568           /* For enumeral types, copy the precision from the integer
4569              type returned above.  If not an INTEGER_TYPE, we can't use
4570              this mode for this type.  */
4571           if (TREE_CODE (typefm) != INTEGER_TYPE)
4572             {
4573               error ("cannot use mode %qs for enumeral types", p);
4574               return NULL_TREE;
4575             }
4576
4577           if (flags & ATTR_FLAG_TYPE_IN_PLACE)
4578             {
4579               TYPE_PRECISION (type) = TYPE_PRECISION (typefm);
4580               typefm = type;
4581             }
4582           else
4583             {
4584               /* We cannot build a type variant, as there's code that assumes
4585                  that TYPE_MAIN_VARIANT has the same mode.  This includes the
4586                  debug generators.  Instead, create a subrange type.  This
4587                  results in all of the enumeral values being emitted only once
4588                  in the original, and the subtype gets them by reference.  */
4589               if (TYPE_UNSIGNED (type))
4590                 typefm = make_unsigned_type (TYPE_PRECISION (typefm));
4591               else
4592                 typefm = make_signed_type (TYPE_PRECISION (typefm));
4593               TREE_TYPE (typefm) = type;
4594             }
4595         }
4596       else if (VECTOR_MODE_P (mode)
4597                ? TREE_CODE (type) != TREE_CODE (TREE_TYPE (typefm))
4598                : TREE_CODE (type) != TREE_CODE (typefm))
4599         {
4600           error ("mode %qs applied to inappropriate type", p);
4601           return NULL_TREE;
4602         }
4603
4604       *node = typefm;
4605     }
4606
4607   return NULL_TREE;
4608 }
4609
4610 /* Handle a "section" attribute; arguments as in
4611    struct attribute_spec.handler.  */
4612
4613 static tree
4614 handle_section_attribute (tree *node, tree ARG_UNUSED (name), tree args,
4615                           int ARG_UNUSED (flags), bool *no_add_attrs)
4616 {
4617   tree decl = *node;
4618
4619   if (targetm.have_named_sections)
4620     {
4621       user_defined_section_attribute = true;
4622
4623       if ((TREE_CODE (decl) == FUNCTION_DECL
4624            || TREE_CODE (decl) == VAR_DECL)
4625           && TREE_CODE (TREE_VALUE (args)) == STRING_CST)
4626         {
4627           if (TREE_CODE (decl) == VAR_DECL
4628               && current_function_decl != NULL_TREE
4629               && !TREE_STATIC (decl))
4630             {
4631               error ("%Jsection attribute cannot be specified for "
4632                      "local variables", decl);
4633               *no_add_attrs = true;
4634             }
4635
4636           /* The decl may have already been given a section attribute
4637              from a previous declaration.  Ensure they match.  */
4638           else if (DECL_SECTION_NAME (decl) != NULL_TREE
4639                    && strcmp (TREE_STRING_POINTER (DECL_SECTION_NAME (decl)),
4640                               TREE_STRING_POINTER (TREE_VALUE (args))) != 0)
4641             {
4642               error ("section of %q+D conflicts with previous declaration",
4643                      *node);
4644               *no_add_attrs = true;
4645             }
4646           else
4647             DECL_SECTION_NAME (decl) = TREE_VALUE (args);
4648         }
4649       else
4650         {
4651           error ("section attribute not allowed for %q+D", *node);
4652           *no_add_attrs = true;
4653         }
4654     }
4655   else
4656     {
4657       error ("%Jsection attributes are not supported for this target", *node);
4658       *no_add_attrs = true;
4659     }
4660
4661   return NULL_TREE;
4662 }
4663
4664 /* Handle a "aligned" attribute; arguments as in
4665    struct attribute_spec.handler.  */
4666
4667 static tree
4668 handle_aligned_attribute (tree *node, tree ARG_UNUSED (name), tree args,
4669                           int flags, bool *no_add_attrs)
4670 {
4671   tree decl = NULL_TREE;
4672   tree *type = NULL;
4673   int is_type = 0;
4674   tree align_expr = (args ? TREE_VALUE (args)
4675                      : size_int (BIGGEST_ALIGNMENT / BITS_PER_UNIT));
4676   int i;
4677
4678   if (DECL_P (*node))
4679     {
4680       decl = *node;
4681       type = &TREE_TYPE (decl);
4682       is_type = TREE_CODE (*node) == TYPE_DECL;
4683     }
4684   else if (TYPE_P (*node))
4685     type = node, is_type = 1;
4686
4687   if (TREE_CODE (align_expr) != INTEGER_CST)
4688     {
4689       error ("requested alignment is not a constant");
4690       *no_add_attrs = true;
4691     }
4692   else if ((i = tree_log2 (align_expr)) == -1)
4693     {
4694       error ("requested alignment is not a power of 2");
4695       *no_add_attrs = true;
4696     }
4697   else if (i > HOST_BITS_PER_INT - 2)
4698     {
4699       error ("requested alignment is too large");
4700       *no_add_attrs = true;
4701     }
4702   else if (is_type)
4703     {
4704       /* If we have a TYPE_DECL, then copy the type, so that we
4705          don't accidentally modify a builtin type.  See pushdecl.  */
4706       if (decl && TREE_TYPE (decl) != error_mark_node
4707           && DECL_ORIGINAL_TYPE (decl) == NULL_TREE)
4708         {
4709           tree tt = TREE_TYPE (decl);
4710           *type = build_variant_type_copy (*type);
4711           DECL_ORIGINAL_TYPE (decl) = tt;
4712           TYPE_NAME (*type) = decl;
4713           TREE_USED (*type) = TREE_USED (decl);
4714           TREE_TYPE (decl) = *type;
4715         }
4716       else if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
4717         *type = build_variant_type_copy (*type);
4718
4719       TYPE_ALIGN (*type) = (1 << i) * BITS_PER_UNIT;
4720       TYPE_USER_ALIGN (*type) = 1;
4721     }
4722   else if (TREE_CODE (decl) != VAR_DECL
4723            && TREE_CODE (decl) != FIELD_DECL)
4724     {
4725       error ("alignment may not be specified for %q+D", decl);
4726       *no_add_attrs = true;
4727     }
4728   else
4729     {
4730       DECL_ALIGN (decl) = (1 << i) * BITS_PER_UNIT;
4731       DECL_USER_ALIGN (decl) = 1;
4732     }
4733
4734   return NULL_TREE;
4735 }
4736
4737 /* Handle a "weak" attribute; arguments as in
4738    struct attribute_spec.handler.  */
4739
4740 static tree
4741 handle_weak_attribute (tree *node, tree name,
4742                        tree ARG_UNUSED (args),
4743                        int ARG_UNUSED (flags),
4744                        bool * ARG_UNUSED (no_add_attrs))
4745 {
4746   if (TREE_CODE (*node) == FUNCTION_DECL
4747       || TREE_CODE (*node) == VAR_DECL)
4748     declare_weak (*node);
4749   else
4750     warning (OPT_Wattributes, "%qE attribute ignored", name);
4751
4752
4753   return NULL_TREE;
4754 }
4755
4756 /* Handle an "alias" attribute; arguments as in
4757    struct attribute_spec.handler.  */
4758
4759 static tree
4760 handle_alias_attribute (tree *node, tree name, tree args,
4761                         int ARG_UNUSED (flags), bool *no_add_attrs)
4762 {
4763   tree decl = *node;
4764
4765   if ((TREE_CODE (decl) == FUNCTION_DECL && DECL_INITIAL (decl))
4766       || (TREE_CODE (decl) != FUNCTION_DECL
4767           && TREE_PUBLIC (decl) && !DECL_EXTERNAL (decl))
4768       /* A static variable declaration is always a tentative definition,
4769          but the alias is a non-tentative definition which overrides.  */
4770       || (TREE_CODE (decl) != FUNCTION_DECL
4771           && ! TREE_PUBLIC (decl) && DECL_INITIAL (decl)))
4772     {
4773       error ("%q+D defined both normally and as an alias", decl);
4774       *no_add_attrs = true;
4775     }
4776
4777   /* Note that the very first time we process a nested declaration,
4778      decl_function_context will not be set.  Indeed, *would* never
4779      be set except for the DECL_INITIAL/DECL_EXTERNAL frobbery that
4780      we do below.  After such frobbery, pushdecl would set the context.
4781      In any case, this is never what we want.  */
4782   else if (decl_function_context (decl) == 0 && current_function_decl == NULL)
4783     {
4784       tree id;
4785
4786       id = TREE_VALUE (args);
4787       if (TREE_CODE (id) != STRING_CST)
4788         {
4789           error ("alias argument not a string");
4790           *no_add_attrs = true;
4791           return NULL_TREE;
4792         }
4793       id = get_identifier (TREE_STRING_POINTER (id));
4794       /* This counts as a use of the object pointed to.  */
4795       TREE_USED (id) = 1;
4796
4797       if (TREE_CODE (decl) == FUNCTION_DECL)
4798         DECL_INITIAL (decl) = error_mark_node;
4799       else
4800         {
4801           if (lookup_attribute ("weakref", DECL_ATTRIBUTES (decl)))
4802             DECL_EXTERNAL (decl) = 1;
4803           else
4804             DECL_EXTERNAL (decl) = 0;
4805           TREE_STATIC (decl) = 1;
4806         }
4807     }
4808   else
4809     {
4810       warning (OPT_Wattributes, "%qE attribute ignored", name);
4811       *no_add_attrs = true;
4812     }
4813
4814   return NULL_TREE;
4815 }
4816
4817 /* Handle a "weakref" attribute; arguments as in struct
4818    attribute_spec.handler.  */
4819
4820 static tree
4821 handle_weakref_attribute (tree *node, tree ARG_UNUSED (name), tree args,
4822                           int flags, bool *no_add_attrs)
4823 {
4824   tree attr = NULL_TREE;
4825
4826   /* We must ignore the attribute when it is associated with
4827      local-scoped decls, since attribute alias is ignored and many
4828      such symbols do not even have a DECL_WEAK field.  */
4829   if (decl_function_context (*node) || current_function_decl)
4830     {
4831       warning (OPT_Wattributes, "%qE attribute ignored", name);
4832       *no_add_attrs = true;
4833       return NULL_TREE;
4834     }
4835
4836   /* The idea here is that `weakref("name")' mutates into `weakref,
4837      alias("name")', and weakref without arguments, in turn,
4838      implicitly adds weak. */
4839
4840   if (args)
4841     {
4842       attr = tree_cons (get_identifier ("alias"), args, attr);
4843       attr = tree_cons (get_identifier ("weakref"), NULL_TREE, attr);
4844
4845       *no_add_attrs = true;
4846
4847       decl_attributes (node, attr, flags);
4848     }
4849   else
4850     {
4851       if (lookup_attribute ("alias", DECL_ATTRIBUTES (*node)))
4852         error ("%Jweakref attribute must appear before alias attribute",
4853                *node);
4854
4855       /* Can't call declare_weak because it wants this to be TREE_PUBLIC,
4856          and that isn't supported; and because it wants to add it to
4857          the list of weak decls, which isn't helpful.  */
4858       DECL_WEAK (*node) = 1;
4859     }
4860
4861   return NULL_TREE;
4862 }
4863
4864 /* Handle an "visibility" attribute; arguments as in
4865    struct attribute_spec.handler.  */
4866
4867 static tree
4868 handle_visibility_attribute (tree *node, tree name, tree args,
4869                              int ARG_UNUSED (flags),
4870                              bool *ARG_UNUSED (no_add_attrs))
4871 {
4872   tree decl = *node;
4873   tree id = TREE_VALUE (args);
4874   enum symbol_visibility vis;
4875
4876   if (TYPE_P (*node))
4877     {
4878       if (TREE_CODE (*node) == ENUMERAL_TYPE)
4879         /* OK */;
4880       else if (TREE_CODE (*node) != RECORD_TYPE && TREE_CODE (*node) != UNION_TYPE)
4881         {
4882           warning (OPT_Wattributes, "%qE attribute ignored on non-class types",
4883                    name);
4884           return NULL_TREE;
4885         }
4886       else if (TYPE_FIELDS (*node))
4887         {
4888           error ("%qE attribute ignored because %qT is already defined",
4889                  name, *node);
4890           return NULL_TREE;
4891         }
4892     }
4893   else if (decl_function_context (decl) != 0 || !TREE_PUBLIC (decl))
4894     {
4895       warning (OPT_Wattributes, "%qE attribute ignored", name);
4896       return NULL_TREE;
4897     }
4898
4899   if (TREE_CODE (id) != STRING_CST)
4900     {
4901       error ("visibility argument not a string");
4902       return NULL_TREE;
4903     }
4904
4905   /*  If this is a type, set the visibility on the type decl.  */
4906   if (TYPE_P (decl))
4907     {
4908       decl = TYPE_NAME (decl);
4909       if (!decl)
4910         return NULL_TREE;
4911       if (TREE_CODE (decl) == IDENTIFIER_NODE)
4912         {
4913            warning (OPT_Wattributes, "%qE attribute ignored on types",
4914                     name);
4915            return NULL_TREE;
4916         }
4917     }
4918
4919   if (strcmp (TREE_STRING_POINTER (id), "default") == 0)
4920     vis = VISIBILITY_DEFAULT;
4921   else if (strcmp (TREE_STRING_POINTER (id), "internal") == 0)
4922     vis = VISIBILITY_INTERNAL;
4923   else if (strcmp (TREE_STRING_POINTER (id), "hidden") == 0)
4924     vis = VISIBILITY_HIDDEN;
4925   else if (strcmp (TREE_STRING_POINTER (id), "protected") == 0)
4926     vis = VISIBILITY_PROTECTED;
4927   else
4928     {
4929       error ("visibility argument must be one of \"default\", \"hidden\", \"protected\" or \"internal\"");
4930       vis = VISIBILITY_DEFAULT;
4931     }
4932
4933   if (DECL_VISIBILITY_SPECIFIED (decl)
4934       && vis != DECL_VISIBILITY (decl)
4935       && lookup_attribute ("visibility", (TYPE_P (*node)
4936                                           ? TYPE_ATTRIBUTES (*node)
4937                                           : DECL_ATTRIBUTES (decl))))
4938     error ("%qD redeclared with different visibility", decl);
4939
4940   DECL_VISIBILITY (decl) = vis;
4941   DECL_VISIBILITY_SPECIFIED (decl) = 1;
4942
4943   /* Go ahead and attach the attribute to the node as well.  This is needed
4944      so we can determine whether we have VISIBILITY_DEFAULT because the
4945      visibility was not specified, or because it was explicitly overridden
4946      from the containing scope.  */
4947
4948   return NULL_TREE;
4949 }
4950
4951 /* Determine the ELF symbol visibility for DECL, which is either a
4952    variable or a function.  It is an error to use this function if a
4953    definition of DECL is not available in this translation unit.
4954    Returns true if the final visibility has been determined by this
4955    function; false if the caller is free to make additional
4956    modifications.  */
4957
4958 bool
4959 c_determine_visibility (tree decl)
4960 {
4961   gcc_assert (TREE_CODE (decl) == VAR_DECL
4962               || TREE_CODE (decl) == FUNCTION_DECL);
4963
4964   /* If the user explicitly specified the visibility with an
4965      attribute, honor that.  DECL_VISIBILITY will have been set during
4966      the processing of the attribute.  We check for an explicit
4967      attribute, rather than just checking DECL_VISIBILITY_SPECIFIED,
4968      to distinguish the use of an attribute from the use of a "#pragma
4969      GCC visibility push(...)"; in the latter case we still want other
4970      considerations to be able to overrule the #pragma.  */
4971   if (lookup_attribute ("visibility", DECL_ATTRIBUTES (decl)))
4972     return true;
4973
4974   /* Anything that is exported must have default visibility.  */
4975   if (TARGET_DLLIMPORT_DECL_ATTRIBUTES
4976       && lookup_attribute ("dllexport", DECL_ATTRIBUTES (decl)))
4977     {
4978       DECL_VISIBILITY (decl) = VISIBILITY_DEFAULT;
4979       DECL_VISIBILITY_SPECIFIED (decl) = 1;
4980       return true;
4981     }
4982
4983   /* Set default visibility to whatever the user supplied with
4984      visibility_specified depending on #pragma GCC visibility.  */
4985   if (!DECL_VISIBILITY_SPECIFIED (decl))
4986     {
4987       DECL_VISIBILITY (decl) = default_visibility;
4988       DECL_VISIBILITY_SPECIFIED (decl) = visibility_options.inpragma;
4989     }
4990   return false;
4991 }
4992
4993 /* Handle an "tls_model" attribute; arguments as in
4994    struct attribute_spec.handler.  */
4995
4996 static tree
4997 handle_tls_model_attribute (tree *node, tree name, tree args,
4998                             int ARG_UNUSED (flags), bool *no_add_attrs)
4999 {
5000   tree id;
5001   tree decl = *node;
5002   enum tls_model kind;
5003
5004   *no_add_attrs = true;
5005
5006   if (!DECL_THREAD_LOCAL_P (decl))
5007     {
5008       warning (OPT_Wattributes, "%qE attribute ignored", name);
5009       return NULL_TREE;
5010     }
5011
5012   kind = DECL_TLS_MODEL (decl);
5013   id = TREE_VALUE (args);
5014   if (TREE_CODE (id) != STRING_CST)
5015     {
5016       error ("tls_model argument not a string");
5017       return NULL_TREE;
5018     }
5019
5020   if (!strcmp (TREE_STRING_POINTER (id), "local-exec"))
5021     kind = TLS_MODEL_LOCAL_EXEC;
5022   else if (!strcmp (TREE_STRING_POINTER (id), "initial-exec"))
5023     kind = TLS_MODEL_INITIAL_EXEC;
5024   else if (!strcmp (TREE_STRING_POINTER (id), "local-dynamic"))
5025     kind = optimize ? TLS_MODEL_LOCAL_DYNAMIC : TLS_MODEL_GLOBAL_DYNAMIC;
5026   else if (!strcmp (TREE_STRING_POINTER (id), "global-dynamic"))
5027     kind = TLS_MODEL_GLOBAL_DYNAMIC;
5028   else
5029     error ("tls_model argument must be one of \"local-exec\", \"initial-exec\", \"local-dynamic\" or \"global-dynamic\"");
5030
5031   DECL_TLS_MODEL (decl) = kind;
5032   return NULL_TREE;
5033 }
5034
5035 /* Handle a "no_instrument_function" attribute; arguments as in
5036    struct attribute_spec.handler.  */
5037
5038 static tree
5039 handle_no_instrument_function_attribute (tree *node, tree name,
5040                                          tree ARG_UNUSED (args),
5041                                          int ARG_UNUSED (flags),
5042                                          bool *no_add_attrs)
5043 {
5044   tree decl = *node;
5045
5046   if (TREE_CODE (decl) != FUNCTION_DECL)
5047     {
5048       error ("%J%qE attribute applies only to functions", decl, name);
5049       *no_add_attrs = true;
5050     }
5051   else if (DECL_INITIAL (decl))
5052     {
5053       error ("%Jcan%'t set %qE attribute after definition", decl, name);
5054       *no_add_attrs = true;
5055     }
5056   else
5057     DECL_NO_INSTRUMENT_FUNCTION_ENTRY_EXIT (decl) = 1;
5058
5059   return NULL_TREE;
5060 }
5061
5062 /* Handle a "malloc" attribute; arguments as in
5063    struct attribute_spec.handler.  */
5064
5065 static tree
5066 handle_malloc_attribute (tree *node, tree name, tree ARG_UNUSED (args),
5067                          int ARG_UNUSED (flags), bool *no_add_attrs)
5068 {
5069   if (TREE_CODE (*node) == FUNCTION_DECL
5070       && POINTER_TYPE_P (TREE_TYPE (TREE_TYPE (*node))))
5071     DECL_IS_MALLOC (*node) = 1;
5072   else
5073     {
5074       warning (OPT_Wattributes, "%qE attribute ignored", name);
5075       *no_add_attrs = true;
5076     }
5077
5078   return NULL_TREE;
5079 }
5080
5081 /* Handle a "returns_twice" attribute; arguments as in
5082    struct attribute_spec.handler.  */
5083
5084 static tree
5085 handle_returns_twice_attribute (tree *node, tree name, tree ARG_UNUSED (args),
5086                          int ARG_UNUSED (flags), bool *no_add_attrs)
5087 {
5088   if (TREE_CODE (*node) == FUNCTION_DECL)
5089     DECL_IS_RETURNS_TWICE (*node) = 1;
5090   else
5091     {
5092       warning (OPT_Wattributes, "%qE attribute ignored", name);
5093       *no_add_attrs = true;
5094     }
5095
5096   return NULL_TREE;
5097 }
5098
5099 /* Handle a "no_limit_stack" attribute; arguments as in
5100    struct attribute_spec.handler.  */
5101
5102 static tree
5103 handle_no_limit_stack_attribute (tree *node, tree name,
5104                                  tree ARG_UNUSED (args),
5105                                  int ARG_UNUSED (flags),
5106                                  bool *no_add_attrs)
5107 {
5108   tree decl = *node;
5109
5110   if (TREE_CODE (decl) != FUNCTION_DECL)
5111     {
5112       error ("%J%qE attribute applies only to functions", decl, name);
5113       *no_add_attrs = true;
5114     }
5115   else if (DECL_INITIAL (decl))
5116     {
5117       error ("%Jcan%'t set %qE attribute after definition", decl, name);
5118       *no_add_attrs = true;
5119     }
5120   else
5121     DECL_NO_LIMIT_STACK (decl) = 1;
5122
5123   return NULL_TREE;
5124 }
5125
5126 /* Handle a "pure" attribute; arguments as in
5127    struct attribute_spec.handler.  */
5128
5129 static tree
5130 handle_pure_attribute (tree *node, tree name, tree ARG_UNUSED (args),
5131                        int ARG_UNUSED (flags), bool *no_add_attrs)
5132 {
5133   if (TREE_CODE (*node) == FUNCTION_DECL)
5134     DECL_IS_PURE (*node) = 1;
5135   /* ??? TODO: Support types.  */
5136   else
5137     {
5138       warning (OPT_Wattributes, "%qE attribute ignored", name);
5139       *no_add_attrs = true;
5140     }
5141
5142   return NULL_TREE;
5143 }
5144
5145 /* Handle a "no vops" attribute; arguments as in
5146    struct attribute_spec.handler.  */
5147
5148 static tree
5149 handle_novops_attribute (tree *node, tree ARG_UNUSED (name),
5150                          tree ARG_UNUSED (args), int ARG_UNUSED (flags),
5151                          bool *ARG_UNUSED (no_add_attrs))
5152 {
5153   gcc_assert (TREE_CODE (*node) == FUNCTION_DECL);
5154   DECL_IS_NOVOPS (*node) = 1;
5155   return NULL_TREE;
5156 }
5157
5158 /* Handle a "deprecated" attribute; arguments as in
5159    struct attribute_spec.handler.  */
5160
5161 static tree
5162 handle_deprecated_attribute (tree *node, tree name,
5163                              tree ARG_UNUSED (args), int flags,
5164                              bool *no_add_attrs)
5165 {
5166   tree type = NULL_TREE;
5167   int warn = 0;
5168   tree what = NULL_TREE;
5169
5170   if (DECL_P (*node))
5171     {
5172       tree decl = *node;
5173       type = TREE_TYPE (decl);
5174
5175       if (TREE_CODE (decl) == TYPE_DECL
5176           || TREE_CODE (decl) == PARM_DECL
5177           || TREE_CODE (decl) == VAR_DECL
5178           || TREE_CODE (decl) == FUNCTION_DECL
5179           || TREE_CODE (decl) == FIELD_DECL)
5180         TREE_DEPRECATED (decl) = 1;
5181       else
5182         warn = 1;
5183     }
5184   else if (TYPE_P (*node))
5185     {
5186       if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
5187         *node = build_variant_type_copy (*node);
5188       TREE_DEPRECATED (*node) = 1;
5189       type = *node;
5190     }
5191   else
5192     warn = 1;
5193
5194   if (warn)
5195     {
5196       *no_add_attrs = true;
5197       if (type && TYPE_NAME (type))
5198         {
5199           if (TREE_CODE (TYPE_NAME (type)) == IDENTIFIER_NODE)
5200             what = TYPE_NAME (*node);
5201           else if (TREE_CODE (TYPE_NAME (type)) == TYPE_DECL
5202                    && DECL_NAME (TYPE_NAME (type)))
5203             what = DECL_NAME (TYPE_NAME (type));
5204         }
5205       if (what)
5206         warning (OPT_Wattributes, "%qE attribute ignored for %qE", name, what);
5207       else
5208         warning (OPT_Wattributes, "%qE attribute ignored", name);
5209     }
5210
5211   return NULL_TREE;
5212 }
5213
5214 /* Handle a "vector_size" attribute; arguments as in
5215    struct attribute_spec.handler.  */
5216
5217 static tree
5218 handle_vector_size_attribute (tree *node, tree name, tree args,
5219                               int ARG_UNUSED (flags),
5220                               bool *no_add_attrs)
5221 {
5222   unsigned HOST_WIDE_INT vecsize, nunits;
5223   enum machine_mode orig_mode;
5224   tree type = *node, new_type, size;
5225
5226   *no_add_attrs = true;
5227
5228   size = TREE_VALUE (args);
5229
5230   if (!host_integerp (size, 1))
5231     {
5232       warning (OPT_Wattributes, "%qE attribute ignored", name);
5233       return NULL_TREE;
5234     }
5235
5236   /* Get the vector size (in bytes).  */
5237   vecsize = tree_low_cst (size, 1);
5238
5239   /* We need to provide for vector pointers, vector arrays, and
5240      functions returning vectors.  For example:
5241
5242        __attribute__((vector_size(16))) short *foo;
5243
5244      In this case, the mode is SI, but the type being modified is
5245      HI, so we need to look further.  */
5246
5247   while (POINTER_TYPE_P (type)
5248          || TREE_CODE (type) == FUNCTION_TYPE
5249          || TREE_CODE (type) == METHOD_TYPE
5250          || TREE_CODE (type) == ARRAY_TYPE)
5251     type = TREE_TYPE (type);
5252
5253   /* Get the mode of the type being modified.  */
5254   orig_mode = TYPE_MODE (type);
5255
5256   if (TREE_CODE (type) == RECORD_TYPE
5257       || (!SCALAR_FLOAT_MODE_P (orig_mode)
5258           && GET_MODE_CLASS (orig_mode) != MODE_INT)
5259       || !host_integerp (TYPE_SIZE_UNIT (type), 1))
5260     {
5261       error ("invalid vector type for attribute %qE", name);
5262       return NULL_TREE;
5263     }
5264
5265   if (vecsize % tree_low_cst (TYPE_SIZE_UNIT (type), 1))
5266     {
5267       error ("vector size not an integral multiple of component size");
5268       return NULL;
5269     }
5270
5271   if (vecsize == 0)
5272     {
5273       error ("zero vector size");
5274       return NULL;
5275     }
5276
5277   /* Calculate how many units fit in the vector.  */
5278   nunits = vecsize / tree_low_cst (TYPE_SIZE_UNIT (type), 1);
5279   if (nunits & (nunits - 1))
5280     {
5281       error ("number of components of the vector not a power of two");
5282       return NULL_TREE;
5283     }
5284
5285   new_type = build_vector_type (type, nunits);
5286
5287   /* Build back pointers if needed.  */
5288   *node = reconstruct_complex_type (*node, new_type);
5289
5290   return NULL_TREE;
5291 }
5292
5293 /* Handle the "nonnull" attribute.  */
5294 static tree
5295 handle_nonnull_attribute (tree *node, tree ARG_UNUSED (name),
5296                           tree args, int ARG_UNUSED (flags),
5297                           bool *no_add_attrs)
5298 {
5299   tree type = *node;
5300   unsigned HOST_WIDE_INT attr_arg_num;
5301
5302   /* If no arguments are specified, all pointer arguments should be
5303      non-null.  Verify a full prototype is given so that the arguments
5304      will have the correct types when we actually check them later.  */
5305   if (!args)
5306     {
5307       if (!TYPE_ARG_TYPES (type))
5308         {
5309           error ("nonnull attribute without arguments on a non-prototype");
5310           *no_add_attrs = true;
5311         }
5312       return NULL_TREE;
5313     }
5314
5315   /* Argument list specified.  Verify that each argument number references
5316      a pointer argument.  */
5317   for (attr_arg_num = 1; args; args = TREE_CHAIN (args))
5318     {
5319       tree argument;
5320       unsigned HOST_WIDE_INT arg_num = 0, ck_num;
5321
5322       if (!get_nonnull_operand (TREE_VALUE (args), &arg_num))
5323         {
5324           error ("nonnull argument has invalid operand number (argument %lu)",
5325                  (unsigned long) attr_arg_num);
5326           *no_add_attrs = true;
5327           return NULL_TREE;
5328         }
5329
5330       argument = TYPE_ARG_TYPES (type);
5331       if (argument)
5332         {
5333           for (ck_num = 1; ; ck_num++)
5334             {
5335               if (!argument || ck_num == arg_num)
5336                 break;
5337               argument = TREE_CHAIN (argument);
5338             }
5339
5340           if (!argument
5341               || TREE_CODE (TREE_VALUE (argument)) == VOID_TYPE)
5342             {
5343               error ("nonnull argument with out-of-range operand number (argument %lu, operand %lu)",
5344                      (unsigned long) attr_arg_num, (unsigned long) arg_num);
5345               *no_add_attrs = true;
5346               return NULL_TREE;
5347             }
5348
5349           if (TREE_CODE (TREE_VALUE (argument)) != POINTER_TYPE)
5350             {
5351               error ("nonnull argument references non-pointer operand (argument %lu, operand %lu)",
5352                    (unsigned long) attr_arg_num, (unsigned long) arg_num);
5353               *no_add_attrs = true;
5354               return NULL_TREE;
5355             }
5356         }
5357     }
5358
5359   return NULL_TREE;
5360 }
5361
5362 /* Check the argument list of a function call for null in argument slots
5363    that are marked as requiring a non-null pointer argument.  */
5364
5365 static void
5366 check_function_nonnull (tree attrs, tree params)
5367 {
5368   tree a, args, param;
5369   int param_num;
5370
5371   for (a = attrs; a; a = TREE_CHAIN (a))
5372     {
5373       if (is_attribute_p ("nonnull", TREE_PURPOSE (a)))
5374         {
5375           args = TREE_VALUE (a);
5376
5377           /* Walk the argument list.  If we encounter an argument number we
5378              should check for non-null, do it.  If the attribute has no args,
5379              then every pointer argument is checked (in which case the check
5380              for pointer type is done in check_nonnull_arg).  */
5381           for (param = params, param_num = 1; ;
5382                param_num++, param = TREE_CHAIN (param))
5383             {
5384               if (!param)
5385         break;
5386               if (!args || nonnull_check_p (args, param_num))
5387         check_function_arguments_recurse (check_nonnull_arg, NULL,
5388                                           TREE_VALUE (param),
5389                                           param_num);
5390             }
5391         }
5392     }
5393 }
5394
5395 /* Check that the Nth argument of a function call (counting backwards
5396    from the end) is a (pointer)0.  */
5397
5398 static void
5399 check_function_sentinel (tree attrs, tree params, tree typelist)
5400 {
5401   tree attr = lookup_attribute ("sentinel", attrs);
5402
5403   if (attr)
5404     {
5405       /* Skip over the named arguments.  */
5406       while (typelist && params)
5407       {
5408         typelist = TREE_CHAIN (typelist);
5409         params = TREE_CHAIN (params);
5410       }
5411
5412       if (typelist || !params)
5413         warning (OPT_Wformat,
5414                  "not enough variable arguments to fit a sentinel");
5415       else
5416         {
5417           tree sentinel, end;
5418           unsigned pos = 0;
5419
5420           if (TREE_VALUE (attr))
5421             {
5422               tree p = TREE_VALUE (TREE_VALUE (attr));
5423               pos = TREE_INT_CST_LOW (p);
5424             }
5425
5426           sentinel = end = params;
5427
5428           /* Advance `end' ahead of `sentinel' by `pos' positions.  */
5429           while (pos > 0 && TREE_CHAIN (end))
5430             {
5431               pos--;
5432               end = TREE_CHAIN (end);
5433             }
5434           if (pos > 0)
5435             {
5436               warning (OPT_Wformat,
5437                        "not enough variable arguments to fit a sentinel");
5438               return;
5439             }
5440
5441           /* Now advance both until we find the last parameter.  */
5442           while (TREE_CHAIN (end))
5443             {
5444               end = TREE_CHAIN (end);
5445               sentinel = TREE_CHAIN (sentinel);
5446             }
5447
5448           /* Validate the sentinel.  */
5449           if ((!POINTER_TYPE_P (TREE_TYPE (TREE_VALUE (sentinel)))
5450                || !integer_zerop (TREE_VALUE (sentinel)))
5451               /* Although __null (in C++) is only an integer we allow it
5452                  nevertheless, as we are guaranteed that it's exactly
5453                  as wide as a pointer, and we don't want to force
5454                  users to cast the NULL they have written there.
5455                  We warn with -Wstrict-null-sentinel, though.  */
5456               && (warn_strict_null_sentinel
5457                   || null_node != TREE_VALUE (sentinel)))
5458             warning (OPT_Wformat, "missing sentinel in function call");
5459         }
5460     }
5461 }
5462
5463 /* Helper for check_function_nonnull; given a list of operands which
5464    must be non-null in ARGS, determine if operand PARAM_NUM should be
5465    checked.  */
5466
5467 static bool
5468 nonnull_check_p (tree args, unsigned HOST_WIDE_INT param_num)
5469 {
5470   unsigned HOST_WIDE_INT arg_num = 0;
5471
5472   for (; args; args = TREE_CHAIN (args))
5473     {
5474       bool found = get_nonnull_operand (TREE_VALUE (args), &arg_num);
5475
5476       gcc_assert (found);
5477
5478       if (arg_num == param_num)
5479         return true;
5480     }
5481   return false;
5482 }
5483
5484 /* Check that the function argument PARAM (which is operand number
5485    PARAM_NUM) is non-null.  This is called by check_function_nonnull
5486    via check_function_arguments_recurse.  */
5487
5488 static void
5489 check_nonnull_arg (void * ARG_UNUSED (ctx), tree param,
5490                    unsigned HOST_WIDE_INT param_num)
5491 {
5492   /* Just skip checking the argument if it's not a pointer.  This can
5493      happen if the "nonnull" attribute was given without an operand
5494      list (which means to check every pointer argument).  */
5495
5496   if (TREE_CODE (TREE_TYPE (param)) != POINTER_TYPE)
5497     return;
5498
5499   if (integer_zerop (param))
5500     warning (OPT_Wnonnull, "null argument where non-null required "
5501              "(argument %lu)", (unsigned long) param_num);
5502 }
5503
5504 /* Helper for nonnull attribute handling; fetch the operand number
5505    from the attribute argument list.  */
5506
5507 static bool
5508 get_nonnull_operand (tree arg_num_expr, unsigned HOST_WIDE_INT *valp)
5509 {
5510   /* Verify the arg number is a constant.  */
5511   if (TREE_CODE (arg_num_expr) != INTEGER_CST
5512       || TREE_INT_CST_HIGH (arg_num_expr) != 0)
5513     return false;
5514
5515   *valp = TREE_INT_CST_LOW (arg_num_expr);
5516   return true;
5517 }
5518
5519 /* Handle a "nothrow" attribute; arguments as in
5520    struct attribute_spec.handler.  */
5521
5522 static tree
5523 handle_nothrow_attribute (tree *node, tree name, tree ARG_UNUSED (args),
5524                           int ARG_UNUSED (flags), bool *no_add_attrs)
5525 {
5526   if (TREE_CODE (*node) == FUNCTION_DECL)
5527     TREE_NOTHROW (*node) = 1;
5528   /* ??? TODO: Support types.  */
5529   else
5530     {
5531       warning (OPT_Wattributes, "%qE attribute ignored", name);
5532       *no_add_attrs = true;
5533     }
5534
5535   return NULL_TREE;
5536 }
5537
5538 /* Handle a "cleanup" attribute; arguments as in
5539    struct attribute_spec.handler.  */
5540
5541 static tree
5542 handle_cleanup_attribute (tree *node, tree name, tree args,
5543                           int ARG_UNUSED (flags), bool *no_add_attrs)
5544 {
5545   tree decl = *node;
5546   tree cleanup_id, cleanup_decl;
5547
5548   /* ??? Could perhaps support cleanups on TREE_STATIC, much like we do
5549      for global destructors in C++.  This requires infrastructure that
5550      we don't have generically at the moment.  It's also not a feature
5551      we'd be missing too much, since we do have attribute constructor.  */
5552   if (TREE_CODE (decl) != VAR_DECL || TREE_STATIC (decl))
5553     {
5554       warning (OPT_Wattributes, "%qE attribute ignored", name);
5555       *no_add_attrs = true;
5556       return NULL_TREE;
5557     }
5558
5559   /* Verify that the argument is a function in scope.  */
5560   /* ??? We could support pointers to functions here as well, if
5561      that was considered desirable.  */
5562   cleanup_id = TREE_VALUE (args);
5563   if (TREE_CODE (cleanup_id) != IDENTIFIER_NODE)
5564     {
5565       error ("cleanup argument not an identifier");
5566       *no_add_attrs = true;
5567       return NULL_TREE;
5568     }
5569   cleanup_decl = lookup_name (cleanup_id);
5570   if (!cleanup_decl || TREE_CODE (cleanup_decl) != FUNCTION_DECL)
5571     {
5572       error ("cleanup argument not a function");
5573       *no_add_attrs = true;
5574       return NULL_TREE;
5575     }
5576
5577   /* That the function has proper type is checked with the
5578      eventual call to build_function_call.  */
5579
5580   return NULL_TREE;
5581 }
5582
5583 /* Handle a "warn_unused_result" attribute.  No special handling.  */
5584
5585 static tree
5586 handle_warn_unused_result_attribute (tree *node, tree name,
5587                                tree ARG_UNUSED (args),
5588                                int ARG_UNUSED (flags), bool *no_add_attrs)
5589 {
5590   /* Ignore the attribute for functions not returning any value.  */
5591   if (VOID_TYPE_P (TREE_TYPE (*node)))
5592     {
5593       warning (OPT_Wattributes, "%qE attribute ignored", name);
5594       *no_add_attrs = true;
5595     }
5596
5597   return NULL_TREE;
5598 }
5599
5600 /* Handle a "sentinel" attribute.  */
5601
5602 static tree
5603 handle_sentinel_attribute (tree *node, tree name, tree args,
5604                            int ARG_UNUSED (flags), bool *no_add_attrs)
5605 {
5606   tree params = TYPE_ARG_TYPES (*node);
5607
5608   if (!params)
5609     {
5610       warning (OPT_Wattributes,
5611                "%qE attribute requires prototypes with named arguments", name);
5612       *no_add_attrs = true;
5613     }
5614   else
5615     {
5616       while (TREE_CHAIN (params))
5617         params = TREE_CHAIN (params);
5618
5619       if (VOID_TYPE_P (TREE_VALUE (params)))
5620         {
5621           warning (OPT_Wattributes,
5622                    "%qE attribute only applies to variadic functions", name);
5623           *no_add_attrs = true;
5624         }
5625     }
5626
5627   if (args)
5628     {
5629       tree position = TREE_VALUE (args);
5630
5631       if (TREE_CODE (position) != INTEGER_CST)
5632         {
5633           warning (0, "requested position is not an integer constant");
5634           *no_add_attrs = true;
5635         }
5636       else
5637         {
5638           if (tree_int_cst_lt (position, integer_zero_node))
5639             {
5640               warning (0, "requested position is less than zero");
5641               *no_add_attrs = true;
5642             }
5643         }
5644     }
5645
5646   return NULL_TREE;
5647 }
5648 \f
5649 /* Check for valid arguments being passed to a function.  */
5650 void
5651 check_function_arguments (tree attrs, tree params, tree typelist)
5652 {
5653   /* Check for null being passed in a pointer argument that must be
5654      non-null.  We also need to do this if format checking is enabled.  */
5655
5656   if (warn_nonnull)
5657     check_function_nonnull (attrs, params);
5658
5659   /* Check for errors in format strings.  */
5660
5661   if (warn_format || warn_missing_format_attribute)
5662       check_function_format (attrs, params);
5663
5664   if (warn_format)
5665     check_function_sentinel (attrs, params, typelist);
5666 }
5667
5668 /* Generic argument checking recursion routine.  PARAM is the argument to
5669    be checked.  PARAM_NUM is the number of the argument.  CALLBACK is invoked
5670    once the argument is resolved.  CTX is context for the callback.  */
5671 void
5672 check_function_arguments_recurse (void (*callback)
5673                                   (void *, tree, unsigned HOST_WIDE_INT),
5674                                   void *ctx, tree param,
5675                                   unsigned HOST_WIDE_INT param_num)
5676 {
5677   if ((TREE_CODE (param) == NOP_EXPR || TREE_CODE (param) == CONVERT_EXPR)
5678       && (TYPE_PRECISION (TREE_TYPE (param))
5679           == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (param, 0)))))
5680     {
5681       /* Strip coercion.  */
5682       check_function_arguments_recurse (callback, ctx,
5683                                         TREE_OPERAND (param, 0), param_num);
5684       return;
5685     }
5686
5687   if (TREE_CODE (param) == CALL_EXPR)
5688     {
5689       tree type = TREE_TYPE (TREE_TYPE (TREE_OPERAND (param, 0)));
5690       tree attrs;
5691       bool found_format_arg = false;
5692
5693       /* See if this is a call to a known internationalization function
5694          that modifies a format arg.  Such a function may have multiple
5695          format_arg attributes (for example, ngettext).  */
5696
5697       for (attrs = TYPE_ATTRIBUTES (type);
5698            attrs;
5699            attrs = TREE_CHAIN (attrs))
5700         if (is_attribute_p ("format_arg", TREE_PURPOSE (attrs)))
5701           {
5702             tree inner_args;
5703             tree format_num_expr;
5704             int format_num;
5705             int i;
5706
5707             /* Extract the argument number, which was previously checked
5708                to be valid.  */
5709             format_num_expr = TREE_VALUE (TREE_VALUE (attrs));
5710
5711             gcc_assert (TREE_CODE (format_num_expr) == INTEGER_CST
5712                         && !TREE_INT_CST_HIGH (format_num_expr));
5713
5714             format_num = TREE_INT_CST_LOW (format_num_expr);
5715
5716             for (inner_args = TREE_OPERAND (param, 1), i = 1;
5717                  inner_args != 0;
5718                  inner_args = TREE_CHAIN (inner_args), i++)
5719               if (i == format_num)
5720                 {
5721                   check_function_arguments_recurse (callback, ctx,
5722                                                     TREE_VALUE (inner_args),
5723                                                     param_num);
5724                   found_format_arg = true;
5725                   break;
5726                 }
5727           }
5728
5729       /* If we found a format_arg attribute and did a recursive check,
5730          we are done with checking this argument.  Otherwise, we continue
5731          and this will be considered a non-literal.  */
5732       if (found_format_arg)
5733         return;
5734     }
5735
5736   if (TREE_CODE (param) == COND_EXPR)
5737     {
5738       /* Check both halves of the conditional expression.  */
5739       check_function_arguments_recurse (callback, ctx,
5740                                         TREE_OPERAND (param, 1), param_num);
5741       check_function_arguments_recurse (callback, ctx,
5742                                         TREE_OPERAND (param, 2), param_num);
5743       return;
5744     }
5745
5746   (*callback) (ctx, param, param_num);
5747 }
5748
5749 /* Function to help qsort sort FIELD_DECLs by name order.  */
5750
5751 int
5752 field_decl_cmp (const void *x_p, const void *y_p)
5753 {
5754   const tree *const x = (const tree *const) x_p;
5755   const tree *const y = (const tree *const) y_p;
5756
5757   if (DECL_NAME (*x) == DECL_NAME (*y))
5758     /* A nontype is "greater" than a type.  */
5759     return (TREE_CODE (*y) == TYPE_DECL) - (TREE_CODE (*x) == TYPE_DECL);
5760   if (DECL_NAME (*x) == NULL_TREE)
5761     return -1;
5762   if (DECL_NAME (*y) == NULL_TREE)
5763     return 1;
5764   if (DECL_NAME (*x) < DECL_NAME (*y))
5765     return -1;
5766   return 1;
5767 }
5768
5769 static struct {
5770   gt_pointer_operator new_value;
5771   void *cookie;
5772 } resort_data;
5773
5774 /* This routine compares two fields like field_decl_cmp but using the
5775 pointer operator in resort_data.  */
5776
5777 static int
5778 resort_field_decl_cmp (const void *x_p, const void *y_p)
5779 {
5780   const tree *const x = (const tree *const) x_p;
5781   const tree *const y = (const tree *const) y_p;
5782
5783   if (DECL_NAME (*x) == DECL_NAME (*y))
5784     /* A nontype is "greater" than a type.  */
5785     return (TREE_CODE (*y) == TYPE_DECL) - (TREE_CODE (*x) == TYPE_DECL);
5786   if (DECL_NAME (*x) == NULL_TREE)
5787     return -1;
5788   if (DECL_NAME (*y) == NULL_TREE)
5789     return 1;
5790   {
5791     tree d1 = DECL_NAME (*x);
5792     tree d2 = DECL_NAME (*y);
5793     resort_data.new_value (&d1, resort_data.cookie);
5794     resort_data.new_value (&d2, resort_data.cookie);
5795     if (d1 < d2)
5796       return -1;
5797   }
5798   return 1;
5799 }
5800
5801 /* Resort DECL_SORTED_FIELDS because pointers have been reordered.  */
5802
5803 void
5804 resort_sorted_fields (void *obj,
5805                       void * ARG_UNUSED (orig_obj),
5806                       gt_pointer_operator new_value,
5807                       void *cookie)
5808 {
5809   struct sorted_fields_type *sf = (struct sorted_fields_type *) obj;
5810   resort_data.new_value = new_value;
5811   resort_data.cookie = cookie;
5812   qsort (&sf->elts[0], sf->len, sizeof (tree),
5813          resort_field_decl_cmp);
5814 }
5815
5816 /* Subroutine of c_parse_error.
5817    Return the result of concatenating LHS and RHS. RHS is really
5818    a string literal, its first character is indicated by RHS_START and
5819    RHS_SIZE is its length (including the terminating NUL character).
5820
5821    The caller is responsible for deleting the returned pointer.  */
5822
5823 static char *
5824 catenate_strings (const char *lhs, const char *rhs_start, int rhs_size)
5825 {
5826   const int lhs_size = strlen (lhs);
5827   char *result = XNEWVEC (char, lhs_size + rhs_size);
5828   strncpy (result, lhs, lhs_size);
5829   strncpy (result + lhs_size, rhs_start, rhs_size);
5830   return result;
5831 }
5832
5833 /* Issue the error given by GMSGID, indicating that it occurred before
5834    TOKEN, which had the associated VALUE.  */
5835
5836 void
5837 c_parse_error (const char *gmsgid, enum cpp_ttype token, tree value)
5838 {
5839 #define catenate_messages(M1, M2) catenate_strings ((M1), (M2), sizeof (M2))
5840
5841   char *message = NULL;
5842
5843   if (token == CPP_EOF)
5844     message = catenate_messages (gmsgid, " at end of input");
5845   else if (token == CPP_CHAR || token == CPP_WCHAR)
5846     {
5847       unsigned int val = TREE_INT_CST_LOW (value);
5848       const char *const ell = (token == CPP_CHAR) ? "" : "L";
5849       if (val <= UCHAR_MAX && ISGRAPH (val))
5850         message = catenate_messages (gmsgid, " before %s'%c'");
5851       else
5852         message = catenate_messages (gmsgid, " before %s'\\x%x'");
5853
5854       error (message, ell, val);
5855       free (message);
5856       message = NULL;
5857     }
5858   else if (token == CPP_STRING || token == CPP_WSTRING)
5859     message = catenate_messages (gmsgid, " before string constant");
5860   else if (token == CPP_NUMBER)
5861     message = catenate_messages (gmsgid, " before numeric constant");
5862   else if (token == CPP_NAME)
5863     {
5864       message = catenate_messages (gmsgid, " before %qE");
5865       error (message, value);
5866       free (message);
5867       message = NULL;
5868     }
5869   else if (token == CPP_PRAGMA)
5870     message = catenate_messages (gmsgid, " before %<#pragma%>");
5871   else if (token == CPP_PRAGMA_EOL)
5872     message = catenate_messages (gmsgid, " before end of line");
5873   else if (token < N_TTYPES)
5874     {
5875       message = catenate_messages (gmsgid, " before %qs token");
5876       error (message, cpp_type2name (token));
5877       free (message);
5878       message = NULL;
5879     }
5880   else
5881     error (gmsgid);
5882
5883   if (message)
5884     {
5885       error (message);
5886       free (message);
5887     }
5888 #undef catenate_messages
5889 }
5890
5891 /* Walk a gimplified function and warn for functions whose return value is
5892    ignored and attribute((warn_unused_result)) is set.  This is done before
5893    inlining, so we don't have to worry about that.  */
5894
5895 void
5896 c_warn_unused_result (tree *top_p)
5897 {
5898   tree t = *top_p;
5899   tree_stmt_iterator i;
5900   tree fdecl, ftype;
5901
5902   switch (TREE_CODE (t))
5903     {
5904     case STATEMENT_LIST:
5905       for (i = tsi_start (*top_p); !tsi_end_p (i); tsi_next (&i))
5906         c_warn_unused_result (tsi_stmt_ptr (i));
5907       break;
5908
5909     case COND_EXPR:
5910       c_warn_unused_result (&COND_EXPR_THEN (t));
5911       c_warn_unused_result (&COND_EXPR_ELSE (t));
5912       break;
5913     case BIND_EXPR:
5914       c_warn_unused_result (&BIND_EXPR_BODY (t));
5915       break;
5916     case TRY_FINALLY_EXPR:
5917     case TRY_CATCH_EXPR:
5918       c_warn_unused_result (&TREE_OPERAND (t, 0));
5919       c_warn_unused_result (&TREE_OPERAND (t, 1));
5920       break;
5921     case CATCH_EXPR:
5922       c_warn_unused_result (&CATCH_BODY (t));
5923       break;
5924     case EH_FILTER_EXPR:
5925       c_warn_unused_result (&EH_FILTER_FAILURE (t));
5926       break;
5927
5928     case CALL_EXPR:
5929       if (TREE_USED (t))
5930         break;
5931
5932       /* This is a naked call, as opposed to a CALL_EXPR nested inside
5933          a MODIFY_EXPR.  All calls whose value is ignored should be
5934          represented like this.  Look for the attribute.  */
5935       fdecl = get_callee_fndecl (t);
5936       if (fdecl)
5937         ftype = TREE_TYPE (fdecl);
5938       else
5939         {
5940           ftype = TREE_TYPE (TREE_OPERAND (t, 0));
5941           /* Look past pointer-to-function to the function type itself.  */
5942           ftype = TREE_TYPE (ftype);
5943         }
5944
5945       if (lookup_attribute ("warn_unused_result", TYPE_ATTRIBUTES (ftype)))
5946         {
5947           if (fdecl)
5948             warning (0, "%Hignoring return value of %qD, "
5949                      "declared with attribute warn_unused_result",
5950                      EXPR_LOCUS (t), fdecl);
5951           else
5952             warning (0, "%Hignoring return value of function "
5953                      "declared with attribute warn_unused_result",
5954                      EXPR_LOCUS (t));
5955         }
5956       break;
5957
5958     default:
5959       /* Not a container, not a call, or a call whose value is used.  */
5960       break;
5961     }
5962 }
5963
5964 /* Convert a character from the host to the target execution character
5965    set.  cpplib handles this, mostly.  */
5966
5967 HOST_WIDE_INT
5968 c_common_to_target_charset (HOST_WIDE_INT c)
5969 {
5970   /* Character constants in GCC proper are sign-extended under -fsigned-char,
5971      zero-extended under -fno-signed-char.  cpplib insists that characters
5972      and character constants are always unsigned.  Hence we must convert
5973      back and forth.  */
5974   cppchar_t uc = ((cppchar_t)c) & ((((cppchar_t)1) << CHAR_BIT)-1);
5975
5976   uc = cpp_host_to_exec_charset (parse_in, uc);
5977
5978   if (flag_signed_char)
5979     return ((HOST_WIDE_INT)uc) << (HOST_BITS_PER_WIDE_INT - CHAR_TYPE_SIZE)
5980                                >> (HOST_BITS_PER_WIDE_INT - CHAR_TYPE_SIZE);
5981   else
5982     return uc;
5983 }
5984
5985 /* Build the result of __builtin_offsetof.  EXPR is a nested sequence of
5986    component references, with STOP_REF, or alternatively an INDIRECT_REF of
5987    NULL, at the bottom; much like the traditional rendering of offsetof as a
5988    macro.  Returns the folded and properly cast result.  */
5989
5990 static tree
5991 fold_offsetof_1 (tree expr, tree stop_ref)
5992 {
5993   enum tree_code code = PLUS_EXPR;
5994   tree base, off, t;
5995
5996   if (expr == stop_ref && TREE_CODE (expr) != ERROR_MARK)
5997     return size_zero_node;
5998
5999   switch (TREE_CODE (expr))
6000     {
6001     case ERROR_MARK:
6002       return expr;
6003
6004     case VAR_DECL:
6005       error ("cannot apply %<offsetof%> to static data member %qD", expr);
6006       return error_mark_node;
6007
6008     case CALL_EXPR:
6009       error ("cannot apply %<offsetof%> when %<operator[]%> is overloaded");
6010       return error_mark_node;
6011
6012     case INTEGER_CST:
6013       gcc_assert (integer_zerop (expr));
6014       return size_zero_node;
6015
6016     case NOP_EXPR:
6017     case INDIRECT_REF:
6018       base = fold_offsetof_1 (TREE_OPERAND (expr, 0), stop_ref);
6019       gcc_assert (base == error_mark_node || base == size_zero_node);
6020       return base;
6021
6022     case COMPONENT_REF:
6023       base = fold_offsetof_1 (TREE_OPERAND (expr, 0), stop_ref);
6024       if (base == error_mark_node)
6025         return base;
6026
6027       t = TREE_OPERAND (expr, 1);
6028       if (DECL_C_BIT_FIELD (t))
6029         {
6030           error ("attempt to take address of bit-field structure "
6031                  "member %qD", t);
6032           return error_mark_node;
6033         }
6034       off = size_binop (PLUS_EXPR, DECL_FIELD_OFFSET (t),
6035                         size_int (tree_low_cst (DECL_FIELD_BIT_OFFSET (t), 1)
6036                                   / BITS_PER_UNIT));
6037       break;
6038
6039     case ARRAY_REF:
6040       base = fold_offsetof_1 (TREE_OPERAND (expr, 0), stop_ref);
6041       if (base == error_mark_node)
6042         return base;
6043
6044       t = TREE_OPERAND (expr, 1);
6045       if (TREE_CODE (t) == INTEGER_CST && tree_int_cst_sgn (t) < 0)
6046         {
6047           code = MINUS_EXPR;
6048           t = fold_build1 (NEGATE_EXPR, TREE_TYPE (t), t);
6049         }
6050       t = convert (sizetype, t);
6051       off = size_binop (MULT_EXPR, TYPE_SIZE_UNIT (TREE_TYPE (expr)), t);
6052       break;
6053
6054     default:
6055       gcc_unreachable ();
6056     }
6057
6058   return size_binop (code, base, off);
6059 }
6060
6061 tree
6062 fold_offsetof (tree expr, tree stop_ref)
6063 {
6064   /* Convert back from the internal sizetype to size_t.  */
6065   return convert (size_type_node, fold_offsetof_1 (expr, stop_ref));
6066 }
6067
6068 /* Print an error message for an invalid lvalue.  USE says
6069    how the lvalue is being used and so selects the error message.  */
6070
6071 void
6072 lvalue_error (enum lvalue_use use)
6073 {
6074   switch (use)
6075     {
6076     case lv_assign:
6077       error ("lvalue required as left operand of assignment");
6078       break;
6079     case lv_increment:
6080       error ("lvalue required as increment operand");
6081       break;
6082     case lv_decrement:
6083       error ("lvalue required as decrement operand");
6084       break;
6085     case lv_addressof:
6086       error ("lvalue required as unary %<&%> operand");
6087       break;
6088     case lv_asm:
6089       error ("lvalue required in asm statement");
6090       break;
6091     default:
6092       gcc_unreachable ();
6093     }
6094 }
6095 \f
6096 /* *PTYPE is an incomplete array.  Complete it with a domain based on
6097    INITIAL_VALUE.  If INITIAL_VALUE is not present, use 1 if DO_DEFAULT
6098    is true.  Return 0 if successful, 1 if INITIAL_VALUE can't be deciphered,
6099    2 if INITIAL_VALUE was NULL, and 3 if INITIAL_VALUE was empty.  */
6100
6101 int
6102 complete_array_type (tree *ptype, tree initial_value, bool do_default)
6103 {
6104   tree maxindex, type, main_type, elt, unqual_elt;
6105   int failure = 0, quals;
6106
6107   maxindex = size_zero_node;
6108   if (initial_value)
6109     {
6110       if (TREE_CODE (initial_value) == STRING_CST)
6111         {
6112           int eltsize
6113             = int_size_in_bytes (TREE_TYPE (TREE_TYPE (initial_value)));
6114           maxindex = size_int (TREE_STRING_LENGTH (initial_value)/eltsize - 1);
6115         }
6116       else if (TREE_CODE (initial_value) == CONSTRUCTOR)
6117         {
6118           VEC(constructor_elt,gc) *v = CONSTRUCTOR_ELTS (initial_value);
6119
6120           if (VEC_empty (constructor_elt, v))
6121             {
6122               if (pedantic)
6123                 failure = 3;
6124               maxindex = integer_minus_one_node;
6125             }
6126           else
6127             {
6128               tree curindex;
6129               unsigned HOST_WIDE_INT cnt;
6130               constructor_elt *ce;
6131
6132               if (VEC_index (constructor_elt, v, 0)->index)
6133                 maxindex = fold_convert (sizetype,
6134                                          VEC_index (constructor_elt,
6135                                                     v, 0)->index);
6136               curindex = maxindex;
6137
6138               for (cnt = 1;
6139                    VEC_iterate (constructor_elt, v, cnt, ce);
6140                    cnt++)
6141                 {
6142                   if (ce->index)
6143                     curindex = fold_convert (sizetype, ce->index);
6144                   else
6145                     curindex = size_binop (PLUS_EXPR, curindex, size_one_node);
6146
6147                   if (tree_int_cst_lt (maxindex, curindex))
6148                     maxindex = curindex;
6149                 }
6150             }
6151         }
6152       else
6153         {
6154           /* Make an error message unless that happened already.  */
6155           if (initial_value != error_mark_node)
6156             failure = 1;
6157         }
6158     }
6159   else
6160     {
6161       failure = 2;
6162       if (!do_default)
6163         return failure;
6164     }
6165
6166   type = *ptype;
6167   elt = TREE_TYPE (type);
6168   quals = TYPE_QUALS (strip_array_types (elt));
6169   if (quals == 0)
6170     unqual_elt = elt;
6171   else
6172     unqual_elt = c_build_qualified_type (elt, TYPE_UNQUALIFIED);
6173
6174   /* Using build_distinct_type_copy and modifying things afterward instead
6175      of using build_array_type to create a new type preserves all of the
6176      TYPE_LANG_FLAG_? bits that the front end may have set.  */
6177   main_type = build_distinct_type_copy (TYPE_MAIN_VARIANT (type));
6178   TREE_TYPE (main_type) = unqual_elt;
6179   TYPE_DOMAIN (main_type) = build_index_type (maxindex);
6180   layout_type (main_type);
6181
6182   if (quals == 0)
6183     type = main_type;
6184   else
6185     type = c_build_qualified_type (main_type, quals);
6186
6187   *ptype = type;
6188   return failure;
6189 }
6190
6191 \f
6192 /* Used to help initialize the builtin-types.def table.  When a type of
6193    the correct size doesn't exist, use error_mark_node instead of NULL.
6194    The later results in segfaults even when a decl using the type doesn't
6195    get invoked.  */
6196
6197 tree
6198 builtin_type_for_size (int size, bool unsignedp)
6199 {
6200   tree type = lang_hooks.types.type_for_size (size, unsignedp);
6201   return type ? type : error_mark_node;
6202 }
6203
6204 /* A helper function for resolve_overloaded_builtin in resolving the
6205    overloaded __sync_ builtins.  Returns a positive power of 2 if the
6206    first operand of PARAMS is a pointer to a supported data type.
6207    Returns 0 if an error is encountered.  */
6208
6209 static int
6210 sync_resolve_size (tree function, tree params)
6211 {
6212   tree type;
6213   int size;
6214
6215   if (params == NULL)
6216     {
6217       error ("too few arguments to function %qE", function);
6218       return 0;
6219     }
6220
6221   type = TREE_TYPE (TREE_VALUE (params));
6222   if (TREE_CODE (type) != POINTER_TYPE)
6223     goto incompatible;
6224
6225   type = TREE_TYPE (type);
6226   if (!INTEGRAL_TYPE_P (type) && !POINTER_TYPE_P (type))
6227     goto incompatible;
6228
6229   size = tree_low_cst (TYPE_SIZE_UNIT (type), 1);
6230   if (size == 1 || size == 2 || size == 4 || size == 8 || size == 16)
6231     return size;
6232
6233  incompatible:
6234   error ("incompatible type for argument %d of %qE", 1, function);
6235   return 0;
6236 }
6237
6238 /* A helper function for resolve_overloaded_builtin.  Adds casts to
6239    PARAMS to make arguments match up with those of FUNCTION.  Drops
6240    the variadic arguments at the end.  Returns false if some error
6241    was encountered; true on success.  */
6242
6243 static bool
6244 sync_resolve_params (tree orig_function, tree function, tree params)
6245 {
6246   tree arg_types = TYPE_ARG_TYPES (TREE_TYPE (function));
6247   tree ptype;
6248   int number;
6249
6250   /* We've declared the implementation functions to use "volatile void *"
6251      as the pointer parameter, so we shouldn't get any complaints from the
6252      call to check_function_arguments what ever type the user used.  */
6253   arg_types = TREE_CHAIN (arg_types);
6254   ptype = TREE_TYPE (TREE_TYPE (TREE_VALUE (params)));
6255   number = 2;
6256
6257   /* For the rest of the values, we need to cast these to FTYPE, so that we
6258      don't get warnings for passing pointer types, etc.  */
6259   while (arg_types != void_list_node)
6260     {
6261       tree val;
6262
6263       params = TREE_CHAIN (params);
6264       if (params == NULL)
6265         {
6266           error ("too few arguments to function %qE", orig_function);
6267           return false;
6268         }
6269
6270       /* ??? Ideally for the first conversion we'd use convert_for_assignment
6271          so that we get warnings for anything that doesn't match the pointer
6272          type.  This isn't portable across the C and C++ front ends atm.  */
6273       val = TREE_VALUE (params);
6274       val = convert (ptype, val);
6275       val = convert (TREE_VALUE (arg_types), val);
6276       TREE_VALUE (params) = val;
6277
6278       arg_types = TREE_CHAIN (arg_types);
6279       number++;
6280     }
6281
6282   /* The definition of these primitives is variadic, with the remaining
6283      being "an optional list of variables protected by the memory barrier".
6284      No clue what that's supposed to mean, precisely, but we consider all
6285      call-clobbered variables to be protected so we're safe.  */
6286   TREE_CHAIN (params) = NULL;
6287
6288   return true;
6289 }
6290
6291 /* A helper function for resolve_overloaded_builtin.  Adds a cast to
6292    RESULT to make it match the type of the first pointer argument in
6293    PARAMS.  */
6294
6295 static tree
6296 sync_resolve_return (tree params, tree result)
6297 {
6298   tree ptype = TREE_TYPE (TREE_TYPE (TREE_VALUE (params)));
6299   ptype = TYPE_MAIN_VARIANT (ptype);
6300   return convert (ptype, result);
6301 }
6302
6303 /* Some builtin functions are placeholders for other expressions.  This
6304    function should be called immediately after parsing the call expression
6305    before surrounding code has committed to the type of the expression.
6306
6307    FUNCTION is the DECL that has been invoked; it is known to be a builtin.
6308    PARAMS is the argument list for the call.  The return value is non-null
6309    when expansion is complete, and null if normal processing should
6310    continue.  */
6311
6312 tree
6313 resolve_overloaded_builtin (tree function, tree params)
6314 {
6315   enum built_in_function orig_code = DECL_FUNCTION_CODE (function);
6316   switch (DECL_BUILT_IN_CLASS (function))
6317     {
6318     case BUILT_IN_NORMAL:
6319       break;
6320     case BUILT_IN_MD:
6321       if (targetm.resolve_overloaded_builtin)
6322         return targetm.resolve_overloaded_builtin (function, params);
6323       else
6324         return NULL_TREE;
6325     default:
6326       return NULL_TREE;
6327     }
6328
6329   /* Handle BUILT_IN_NORMAL here.  */
6330   switch (orig_code)
6331     {
6332     case BUILT_IN_FETCH_AND_ADD_N:
6333     case BUILT_IN_FETCH_AND_SUB_N:
6334     case BUILT_IN_FETCH_AND_OR_N:
6335     case BUILT_IN_FETCH_AND_AND_N:
6336     case BUILT_IN_FETCH_AND_XOR_N:
6337     case BUILT_IN_FETCH_AND_NAND_N:
6338     case BUILT_IN_ADD_AND_FETCH_N:
6339     case BUILT_IN_SUB_AND_FETCH_N:
6340     case BUILT_IN_OR_AND_FETCH_N:
6341     case BUILT_IN_AND_AND_FETCH_N:
6342     case BUILT_IN_XOR_AND_FETCH_N:
6343     case BUILT_IN_NAND_AND_FETCH_N:
6344     case BUILT_IN_BOOL_COMPARE_AND_SWAP_N:
6345     case BUILT_IN_VAL_COMPARE_AND_SWAP_N:
6346     case BUILT_IN_LOCK_TEST_AND_SET_N:
6347     case BUILT_IN_LOCK_RELEASE_N:
6348       {
6349         int n = sync_resolve_size (function, params);
6350         tree new_function, result;
6351
6352         if (n == 0)
6353           return error_mark_node;
6354
6355         new_function = built_in_decls[orig_code + exact_log2 (n) + 1];
6356         if (!sync_resolve_params (function, new_function, params))
6357           return error_mark_node;
6358
6359         result = build_function_call (new_function, params);
6360         if (orig_code != BUILT_IN_BOOL_COMPARE_AND_SWAP_N
6361             && orig_code != BUILT_IN_LOCK_RELEASE_N)
6362           result = sync_resolve_return (params, result);
6363
6364         return result;
6365       }
6366
6367     default:
6368       return NULL_TREE;
6369     }
6370 }
6371
6372 /* Ignoring their sign, return true if two scalar types are the same.  */
6373 bool
6374 same_scalar_type_ignoring_signedness (tree t1, tree t2)
6375 {
6376   enum tree_code c1 = TREE_CODE (t1), c2 = TREE_CODE (t2);
6377
6378   gcc_assert ((c1 == INTEGER_TYPE || c1 == REAL_TYPE)
6379               && (c2 == INTEGER_TYPE || c2 == REAL_TYPE));
6380
6381   /* Equality works here because c_common_signed_type uses
6382      TYPE_MAIN_VARIANT.  */
6383   return lang_hooks.types.signed_type (t1)
6384     == lang_hooks.types.signed_type (t2);
6385 }
6386
6387 /* Check for missing format attributes on function pointers.  LTYPE is
6388    the new type or left-hand side type.  RTYPE is the old type or
6389    right-hand side type.  Returns TRUE if LTYPE is missing the desired
6390    attribute.  */
6391
6392 bool
6393 check_missing_format_attribute (tree ltype, tree rtype)
6394 {
6395   tree const ttr = TREE_TYPE (rtype), ttl = TREE_TYPE (ltype);
6396   tree ra;
6397
6398   for (ra = TYPE_ATTRIBUTES (ttr); ra; ra = TREE_CHAIN (ra))
6399     if (is_attribute_p ("format", TREE_PURPOSE (ra)))
6400       break;
6401   if (ra)
6402     {
6403       tree la;
6404       for (la = TYPE_ATTRIBUTES (ttl); la; la = TREE_CHAIN (la))
6405         if (is_attribute_p ("format", TREE_PURPOSE (la)))
6406           break;
6407       return !la;
6408     }
6409   else
6410     return false;
6411 }
6412
6413 /* Subscripting with type char is likely to lose on a machine where
6414    chars are signed.  So warn on any machine, but optionally.  Don't
6415    warn for unsigned char since that type is safe.  Don't warn for
6416    signed char because anyone who uses that must have done so
6417    deliberately. Furthermore, we reduce the false positive load by
6418    warning only for non-constant value of type char.  */
6419
6420 void
6421 warn_array_subscript_with_type_char (tree index)
6422 {
6423   if (TYPE_MAIN_VARIANT (TREE_TYPE (index)) == char_type_node
6424       && TREE_CODE (index) != INTEGER_CST)
6425     warning (OPT_Wchar_subscripts, "array subscript has type %<char%>");
6426 }
6427
6428
6429 #include "gt-c-common.h"