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 static int
3801 match_case_to_enum (splay_tree_node node, void *data)
3802 {
3803   tree label = (tree) node->value;
3804   tree type = (tree) data;
3805
3806   /* Skip default case.  */
3807   if (!CASE_LOW (label))
3808     return 0;
3809
3810   /* If TREE_ADDRESSABLE is not set, that means CASE_LOW did not appear
3811      when we did our enum->case scan.  Reset our scratch bit after.  */
3812   if (!TREE_ADDRESSABLE (label))
3813     match_case_to_enum_1 (CASE_LOW (label), type, label);
3814   else
3815     TREE_ADDRESSABLE (label) = 0;
3816
3817   /* If CASE_HIGH is non-null, we have a range.  Here we must search.
3818      Note that the old code in stmt.c did not check for the values in
3819      the range either, just the endpoints.  */
3820   if (CASE_HIGH (label))
3821     {
3822       tree chain, key = CASE_HIGH (label);
3823
3824       for (chain = TYPE_VALUES (type);
3825            chain && !tree_int_cst_equal (key, TREE_VALUE (chain));
3826            chain = TREE_CHAIN (chain))
3827         continue;
3828       if (!chain)
3829         match_case_to_enum_1 (key, type, label);
3830     }
3831
3832   return 0;
3833 }
3834
3835 /* Handle -Wswitch*.  Called from the front end after parsing the
3836    switch construct.  */
3837 /* ??? Should probably be somewhere generic, since other languages
3838    besides C and C++ would want this.  At the moment, however, C/C++
3839    are the only tree-ssa languages that support enumerations at all,
3840    so the point is moot.  */
3841
3842 void
3843 c_do_switch_warnings (splay_tree cases, location_t switch_location,
3844                       tree type, tree cond)
3845 {
3846   splay_tree_node default_node;
3847
3848   if (!warn_switch && !warn_switch_enum && !warn_switch_default)
3849     return;
3850
3851   default_node = splay_tree_lookup (cases, (splay_tree_key) NULL);
3852   if (!default_node)
3853     warning (OPT_Wswitch_default, "%Hswitch missing default case",
3854              &switch_location);
3855
3856   /* If the switch expression was an enumerated type, check that
3857      exactly all enumeration literals are covered by the cases.
3858      The check is made when -Wswitch was specified and there is no
3859      default case, or when -Wswitch-enum was specified.  */
3860   if (((warn_switch && !default_node) || warn_switch_enum)
3861       && type && TREE_CODE (type) == ENUMERAL_TYPE
3862       && TREE_CODE (cond) != INTEGER_CST)
3863     {
3864       tree chain;
3865
3866       /* The time complexity here is O(N*lg(N)) worst case, but for the
3867          common case of monotonically increasing enumerators, it is
3868          O(N), since the nature of the splay tree will keep the next
3869          element adjacent to the root at all times.  */
3870
3871       for (chain = TYPE_VALUES (type); chain; chain = TREE_CHAIN (chain))
3872         {
3873           splay_tree_node node
3874             = splay_tree_lookup (cases, (splay_tree_key) TREE_VALUE (chain));
3875           if (!node)
3876             {
3877               tree low_value = TREE_VALUE (chain);
3878               splay_tree_node low_bound;
3879               splay_tree_node high_bound;
3880               /* Even though there wasn't an exact match, there might be a
3881                  case range which includes the enumator's value.  */
3882               low_bound = splay_tree_predecessor (cases,
3883                                                   (splay_tree_key) low_value);
3884               high_bound = splay_tree_successor (cases,
3885                                                  (splay_tree_key) low_value);
3886
3887               /* It is smaller than the LOW_VALUE, so there is no need to check
3888                  unless the LOW_BOUND is in fact itself a case range.  */
3889               if (low_bound
3890                   && CASE_HIGH ((tree) low_bound->value)
3891                   && tree_int_cst_compare (CASE_HIGH ((tree) low_bound->value),
3892                                             low_value) >= 0)
3893                 node = low_bound;
3894               /* The low end of that range is bigger than the current value. */
3895               else if (high_bound
3896                        && (tree_int_cst_compare ((tree) high_bound->key,
3897                                                  low_value)
3898                            <= 0))
3899                 node = high_bound;
3900             }
3901           if (node)
3902             {
3903               /* Mark the CASE_LOW part of the case entry as seen, so
3904                  that we save time later.  Choose TREE_ADDRESSABLE
3905                  randomly as a bit that won't have been set to-date.  */
3906               tree label = (tree) node->value;
3907               TREE_ADDRESSABLE (label) = 1;
3908             }
3909           else
3910             {
3911               /* Warn if there are enumerators that don't correspond to
3912                  case expressions.  */
3913               warning (0, "%Henumeration value %qE not handled in switch",
3914                        &switch_location, TREE_PURPOSE (chain));
3915             }
3916         }
3917
3918       /* Warn if there are case expressions that don't correspond to
3919          enumerators.  This can occur since C and C++ don't enforce
3920          type-checking of assignments to enumeration variables.
3921
3922          The time complexity here is O(N**2) worst case, since we've
3923          not sorted the enumeration values.  However, in the absence
3924          of case ranges this is O(N), since all single cases that
3925          corresponded to enumerations have been marked above.  */
3926
3927       splay_tree_foreach (cases, match_case_to_enum, type);
3928     }
3929 }
3930
3931 /* Finish an expression taking the address of LABEL (an
3932    IDENTIFIER_NODE).  Returns an expression for the address.  */
3933
3934 tree
3935 finish_label_address_expr (tree label)
3936 {
3937   tree result;
3938
3939   if (pedantic)
3940     pedwarn ("taking the address of a label is non-standard");
3941
3942   if (label == error_mark_node)
3943     return error_mark_node;
3944
3945   label = lookup_label (label);
3946   if (label == NULL_TREE)
3947     result = null_pointer_node;
3948   else
3949     {
3950       TREE_USED (label) = 1;
3951       result = build1 (ADDR_EXPR, ptr_type_node, label);
3952       /* The current function in not necessarily uninlinable.
3953          Computed gotos are incompatible with inlining, but the value
3954          here could be used only in a diagnostic, for example.  */
3955     }
3956
3957   return result;
3958 }
3959
3960 /* Hook used by expand_expr to expand language-specific tree codes.  */
3961 /* The only things that should go here are bits needed to expand
3962    constant initializers.  Everything else should be handled by the
3963    gimplification routines.  */
3964
3965 rtx
3966 c_expand_expr (tree exp, rtx target, enum machine_mode tmode,
3967                int modifier /* Actually enum_modifier.  */,
3968                rtx *alt_rtl)
3969 {
3970   switch (TREE_CODE (exp))
3971     {
3972     case COMPOUND_LITERAL_EXPR:
3973       {
3974         /* Initialize the anonymous variable declared in the compound
3975            literal, then return the variable.  */
3976         tree decl = COMPOUND_LITERAL_EXPR_DECL (exp);
3977         emit_local_var (decl);
3978         return expand_expr_real (decl, target, tmode, modifier, alt_rtl);
3979       }
3980
3981     default:
3982       gcc_unreachable ();
3983     }
3984 }
3985
3986 /* Hook used by staticp to handle language-specific tree codes.  */
3987
3988 tree
3989 c_staticp (tree exp)
3990 {
3991   return (TREE_CODE (exp) == COMPOUND_LITERAL_EXPR
3992           && TREE_STATIC (COMPOUND_LITERAL_EXPR_DECL (exp))
3993           ? exp : NULL);
3994 }
3995 \f
3996
3997 /* Given a boolean expression ARG, return a tree representing an increment
3998    or decrement (as indicated by CODE) of ARG.  The front end must check for
3999    invalid cases (e.g., decrement in C++).  */
4000 tree
4001 boolean_increment (enum tree_code code, tree arg)
4002 {
4003   tree val;
4004   tree true_res = boolean_true_node;
4005
4006   arg = stabilize_reference (arg);
4007   switch (code)
4008     {
4009     case PREINCREMENT_EXPR:
4010       val = build2 (MODIFY_EXPR, TREE_TYPE (arg), arg, true_res);
4011       break;
4012     case POSTINCREMENT_EXPR:
4013       val = build2 (MODIFY_EXPR, TREE_TYPE (arg), arg, true_res);
4014       arg = save_expr (arg);
4015       val = build2 (COMPOUND_EXPR, TREE_TYPE (arg), val, arg);
4016       val = build2 (COMPOUND_EXPR, TREE_TYPE (arg), arg, val);
4017       break;
4018     case PREDECREMENT_EXPR:
4019       val = build2 (MODIFY_EXPR, TREE_TYPE (arg), arg,
4020                     invert_truthvalue (arg));
4021       break;
4022     case POSTDECREMENT_EXPR:
4023       val = build2 (MODIFY_EXPR, TREE_TYPE (arg), arg,
4024                     invert_truthvalue (arg));
4025       arg = save_expr (arg);
4026       val = build2 (COMPOUND_EXPR, TREE_TYPE (arg), val, arg);
4027       val = build2 (COMPOUND_EXPR, TREE_TYPE (arg), arg, val);
4028       break;
4029     default:
4030       gcc_unreachable ();
4031     }
4032   TREE_SIDE_EFFECTS (val) = 1;
4033   return val;
4034 }
4035 \f
4036 /* Built-in macros for stddef.h, that require macros defined in this
4037    file.  */
4038 void
4039 c_stddef_cpp_builtins(void)
4040 {
4041   builtin_define_with_value ("__SIZE_TYPE__", SIZE_TYPE, 0);
4042   builtin_define_with_value ("__PTRDIFF_TYPE__", PTRDIFF_TYPE, 0);
4043   builtin_define_with_value ("__WCHAR_TYPE__", MODIFIED_WCHAR_TYPE, 0);
4044   builtin_define_with_value ("__WINT_TYPE__", WINT_TYPE, 0);
4045   builtin_define_with_value ("__INTMAX_TYPE__", INTMAX_TYPE, 0);
4046   builtin_define_with_value ("__UINTMAX_TYPE__", UINTMAX_TYPE, 0);
4047 }
4048
4049 static void
4050 c_init_attributes (void)
4051 {
4052   /* Fill in the built_in_attributes array.  */
4053 #define DEF_ATTR_NULL_TREE(ENUM)                                \
4054   built_in_attributes[(int) ENUM] = NULL_TREE;
4055 #define DEF_ATTR_INT(ENUM, VALUE)                               \
4056   built_in_attributes[(int) ENUM] = build_int_cst (NULL_TREE, VALUE);
4057 #define DEF_ATTR_IDENT(ENUM, STRING)                            \
4058   built_in_attributes[(int) ENUM] = get_identifier (STRING);
4059 #define DEF_ATTR_TREE_LIST(ENUM, PURPOSE, VALUE, CHAIN) \
4060   built_in_attributes[(int) ENUM]                       \
4061     = tree_cons (built_in_attributes[(int) PURPOSE],    \
4062                  built_in_attributes[(int) VALUE],      \
4063                  built_in_attributes[(int) CHAIN]);
4064 #include "builtin-attrs.def"
4065 #undef DEF_ATTR_NULL_TREE
4066 #undef DEF_ATTR_INT
4067 #undef DEF_ATTR_IDENT
4068 #undef DEF_ATTR_TREE_LIST
4069 }
4070
4071 /* Attribute handlers common to C front ends.  */
4072
4073 /* Handle a "packed" attribute; arguments as in
4074    struct attribute_spec.handler.  */
4075
4076 static tree
4077 handle_packed_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4078                          int flags, bool *no_add_attrs)
4079 {
4080   if (TYPE_P (*node))
4081     {
4082       if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
4083         *node = build_variant_type_copy (*node);
4084       TYPE_PACKED (*node) = 1;
4085     }
4086   else if (TREE_CODE (*node) == FIELD_DECL)
4087     {
4088       if (TYPE_ALIGN (TREE_TYPE (*node)) <= BITS_PER_UNIT)
4089         warning (OPT_Wattributes,
4090                  "%qE attribute ignored for field of type %qT",
4091                  name, TREE_TYPE (*node));
4092       else
4093         DECL_PACKED (*node) = 1;
4094     }
4095   /* We can't set DECL_PACKED for a VAR_DECL, because the bit is
4096      used for DECL_REGISTER.  It wouldn't mean anything anyway.
4097      We can't set DECL_PACKED on the type of a TYPE_DECL, because
4098      that changes what the typedef is typing.  */
4099   else
4100     {
4101       warning (OPT_Wattributes, "%qE attribute ignored", name);
4102       *no_add_attrs = true;
4103     }
4104
4105   return NULL_TREE;
4106 }
4107
4108 /* Handle a "nocommon" attribute; arguments as in
4109    struct attribute_spec.handler.  */
4110
4111 static tree
4112 handle_nocommon_attribute (tree *node, tree name,
4113                            tree ARG_UNUSED (args),
4114                            int ARG_UNUSED (flags), bool *no_add_attrs)
4115 {
4116   if (TREE_CODE (*node) == VAR_DECL)
4117     DECL_COMMON (*node) = 0;
4118   else
4119     {
4120       warning (OPT_Wattributes, "%qE attribute ignored", name);
4121       *no_add_attrs = true;
4122     }
4123
4124   return NULL_TREE;
4125 }
4126
4127 /* Handle a "common" attribute; arguments as in
4128    struct attribute_spec.handler.  */
4129
4130 static tree
4131 handle_common_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4132                          int ARG_UNUSED (flags), bool *no_add_attrs)
4133 {
4134   if (TREE_CODE (*node) == VAR_DECL)
4135     DECL_COMMON (*node) = 1;
4136   else
4137     {
4138       warning (OPT_Wattributes, "%qE attribute ignored", name);
4139       *no_add_attrs = true;
4140     }
4141
4142   return NULL_TREE;
4143 }
4144
4145 /* Handle a "noreturn" attribute; arguments as in
4146    struct attribute_spec.handler.  */
4147
4148 static tree
4149 handle_noreturn_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4150                            int ARG_UNUSED (flags), bool *no_add_attrs)
4151 {
4152   tree type = TREE_TYPE (*node);
4153
4154   /* See FIXME comment in c_common_attribute_table.  */
4155   if (TREE_CODE (*node) == FUNCTION_DECL)
4156     TREE_THIS_VOLATILE (*node) = 1;
4157   else if (TREE_CODE (type) == POINTER_TYPE
4158            && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE)
4159     TREE_TYPE (*node)
4160       = build_pointer_type
4161         (build_type_variant (TREE_TYPE (type),
4162                              TYPE_READONLY (TREE_TYPE (type)), 1));
4163   else
4164     {
4165       warning (OPT_Wattributes, "%qE attribute ignored", name);
4166       *no_add_attrs = true;
4167     }
4168
4169   return NULL_TREE;
4170 }
4171
4172 /* Handle a "noinline" attribute; arguments as in
4173    struct attribute_spec.handler.  */
4174
4175 static tree
4176 handle_noinline_attribute (tree *node, tree name,
4177                            tree ARG_UNUSED (args),
4178                            int ARG_UNUSED (flags), bool *no_add_attrs)
4179 {
4180   if (TREE_CODE (*node) == FUNCTION_DECL)
4181     DECL_UNINLINABLE (*node) = 1;
4182   else
4183     {
4184       warning (OPT_Wattributes, "%qE attribute ignored", name);
4185       *no_add_attrs = true;
4186     }
4187
4188   return NULL_TREE;
4189 }
4190
4191 /* Handle a "always_inline" attribute; arguments as in
4192    struct attribute_spec.handler.  */
4193
4194 static tree
4195 handle_always_inline_attribute (tree *node, tree name,
4196                                 tree ARG_UNUSED (args),
4197                                 int ARG_UNUSED (flags),
4198                                 bool *no_add_attrs)
4199 {
4200   if (TREE_CODE (*node) == FUNCTION_DECL)
4201     {
4202       /* Do nothing else, just set the attribute.  We'll get at
4203          it later with lookup_attribute.  */
4204     }
4205   else
4206     {
4207       warning (OPT_Wattributes, "%qE attribute ignored", name);
4208       *no_add_attrs = true;
4209     }
4210
4211   return NULL_TREE;
4212 }
4213
4214 /* Handle a "flatten" attribute; arguments as in
4215    struct attribute_spec.handler.  */
4216
4217 static tree
4218 handle_flatten_attribute (tree *node, tree name,
4219                           tree args ATTRIBUTE_UNUSED,
4220                           int flags ATTRIBUTE_UNUSED, bool *no_add_attrs)
4221 {
4222   if (TREE_CODE (*node) == FUNCTION_DECL)
4223     /* Do nothing else, just set the attribute.  We'll get at
4224        it later with lookup_attribute.  */
4225     ;
4226   else
4227     {
4228       warning (OPT_Wattributes, "%qE attribute ignored", name);
4229       *no_add_attrs = true;
4230     }
4231
4232   return NULL_TREE;
4233 }
4234
4235
4236 /* Handle a "used" attribute; arguments as in
4237    struct attribute_spec.handler.  */
4238
4239 static tree
4240 handle_used_attribute (tree *pnode, tree name, tree ARG_UNUSED (args),
4241                        int ARG_UNUSED (flags), bool *no_add_attrs)
4242 {
4243   tree node = *pnode;
4244
4245   if (TREE_CODE (node) == FUNCTION_DECL
4246       || (TREE_CODE (node) == VAR_DECL && TREE_STATIC (node)))
4247     {
4248       TREE_USED (node) = 1;
4249       DECL_PRESERVE_P (node) = 1;
4250     }
4251   else
4252     {
4253       warning (OPT_Wattributes, "%qE attribute ignored", name);
4254       *no_add_attrs = true;
4255     }
4256
4257   return NULL_TREE;
4258 }
4259
4260 /* Handle a "unused" attribute; arguments as in
4261    struct attribute_spec.handler.  */
4262
4263 static tree
4264 handle_unused_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4265                          int flags, bool *no_add_attrs)
4266 {
4267   if (DECL_P (*node))
4268     {
4269       tree decl = *node;
4270
4271       if (TREE_CODE (decl) == PARM_DECL
4272           || TREE_CODE (decl) == VAR_DECL
4273           || TREE_CODE (decl) == FUNCTION_DECL
4274           || TREE_CODE (decl) == LABEL_DECL
4275           || TREE_CODE (decl) == TYPE_DECL)
4276         TREE_USED (decl) = 1;
4277       else
4278         {
4279           warning (OPT_Wattributes, "%qE attribute ignored", name);
4280           *no_add_attrs = true;
4281         }
4282     }
4283   else
4284     {
4285       if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
4286         *node = build_variant_type_copy (*node);
4287       TREE_USED (*node) = 1;
4288     }
4289
4290   return NULL_TREE;
4291 }
4292
4293 /* Handle a "externally_visible" attribute; arguments as in
4294    struct attribute_spec.handler.  */
4295
4296 static tree
4297 handle_externally_visible_attribute (tree *pnode, tree name,
4298                                      tree ARG_UNUSED (args),
4299                                      int ARG_UNUSED (flags),
4300                                      bool *no_add_attrs)
4301 {
4302   tree node = *pnode;
4303
4304   if (TREE_CODE (node) == FUNCTION_DECL || TREE_CODE (node) == VAR_DECL)
4305     {
4306       if ((!TREE_STATIC (node) && TREE_CODE (node) != FUNCTION_DECL
4307            && !DECL_EXTERNAL (node)) || !TREE_PUBLIC (node))
4308         {
4309           warning (OPT_Wattributes,
4310                    "%qE attribute have effect only on public objects", name);
4311           *no_add_attrs = true;
4312         }
4313     }
4314   else
4315     {
4316       warning (OPT_Wattributes, "%qE attribute ignored", name);
4317       *no_add_attrs = true;
4318     }
4319
4320   return NULL_TREE;
4321 }
4322
4323 /* Handle a "const" attribute; arguments as in
4324    struct attribute_spec.handler.  */
4325
4326 static tree
4327 handle_const_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4328                         int ARG_UNUSED (flags), bool *no_add_attrs)
4329 {
4330   tree type = TREE_TYPE (*node);
4331
4332   /* See FIXME comment on noreturn in c_common_attribute_table.  */
4333   if (TREE_CODE (*node) == FUNCTION_DECL)
4334     TREE_READONLY (*node) = 1;
4335   else if (TREE_CODE (type) == POINTER_TYPE
4336            && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE)
4337     TREE_TYPE (*node)
4338       = build_pointer_type
4339         (build_type_variant (TREE_TYPE (type), 1,
4340                              TREE_THIS_VOLATILE (TREE_TYPE (type))));
4341   else
4342     {
4343       warning (OPT_Wattributes, "%qE attribute ignored", name);
4344       *no_add_attrs = true;
4345     }
4346
4347   return NULL_TREE;
4348 }
4349
4350 /* Handle a "transparent_union" attribute; arguments as in
4351    struct attribute_spec.handler.  */
4352
4353 static tree
4354 handle_transparent_union_attribute (tree *node, tree name,
4355                                     tree ARG_UNUSED (args), int flags,
4356                                     bool *no_add_attrs)
4357 {
4358   tree type = NULL;
4359
4360   *no_add_attrs = true;
4361
4362   if (DECL_P (*node))
4363     {
4364       if (TREE_CODE (*node) != TYPE_DECL)
4365         goto ignored;
4366       node = &TREE_TYPE (*node);
4367       type = *node;
4368     }
4369   else if (TYPE_P (*node))
4370     type = *node;
4371   else
4372     goto ignored;
4373
4374   if (TREE_CODE (type) == UNION_TYPE)
4375     {
4376       /* When IN_PLACE is set, leave the check for FIELDS and MODE to
4377          the code in finish_struct.  */
4378       if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
4379         {
4380           if (TYPE_FIELDS (type) == NULL_TREE
4381               || TYPE_MODE (type) != DECL_MODE (TYPE_FIELDS (type)))
4382             goto ignored;
4383
4384           /* A type variant isn't good enough, since we don't a cast
4385              to such a type removed as a no-op.  */
4386           *node = type = build_duplicate_type (type);
4387         }
4388
4389       TYPE_TRANSPARENT_UNION (type) = 1;
4390       return NULL_TREE;
4391     }
4392
4393  ignored:
4394   warning (OPT_Wattributes, "%qE attribute ignored", name);
4395   return NULL_TREE;
4396 }
4397
4398 /* Handle a "constructor" attribute; arguments as in
4399    struct attribute_spec.handler.  */
4400
4401 static tree
4402 handle_constructor_attribute (tree *node, tree name,
4403                               tree ARG_UNUSED (args),
4404                               int ARG_UNUSED (flags),
4405                               bool *no_add_attrs)
4406 {
4407   tree decl = *node;
4408   tree type = TREE_TYPE (decl);
4409
4410   if (TREE_CODE (decl) == FUNCTION_DECL
4411       && TREE_CODE (type) == FUNCTION_TYPE
4412       && decl_function_context (decl) == 0)
4413     {
4414       DECL_STATIC_CONSTRUCTOR (decl) = 1;
4415       TREE_USED (decl) = 1;
4416     }
4417   else
4418     {
4419       warning (OPT_Wattributes, "%qE attribute ignored", name);
4420       *no_add_attrs = true;
4421     }
4422
4423   return NULL_TREE;
4424 }
4425
4426 /* Handle a "destructor" attribute; arguments as in
4427    struct attribute_spec.handler.  */
4428
4429 static tree
4430 handle_destructor_attribute (tree *node, tree name,
4431                              tree ARG_UNUSED (args),
4432                              int ARG_UNUSED (flags),
4433                              bool *no_add_attrs)
4434 {
4435   tree decl = *node;
4436   tree type = TREE_TYPE (decl);
4437
4438   if (TREE_CODE (decl) == FUNCTION_DECL
4439       && TREE_CODE (type) == FUNCTION_TYPE
4440       && decl_function_context (decl) == 0)
4441     {
4442       DECL_STATIC_DESTRUCTOR (decl) = 1;
4443       TREE_USED (decl) = 1;
4444     }
4445   else
4446     {
4447       warning (OPT_Wattributes, "%qE attribute ignored", name);
4448       *no_add_attrs = true;
4449     }
4450
4451   return NULL_TREE;
4452 }
4453
4454 /* Handle a "mode" attribute; arguments as in
4455    struct attribute_spec.handler.  */
4456
4457 static tree
4458 handle_mode_attribute (tree *node, tree name, tree args,
4459                        int ARG_UNUSED (flags), bool *no_add_attrs)
4460 {
4461   tree type = *node;
4462
4463   *no_add_attrs = true;
4464
4465   if (TREE_CODE (TREE_VALUE (args)) != IDENTIFIER_NODE)
4466     warning (OPT_Wattributes, "%qE attribute ignored", name);
4467   else
4468     {
4469       int j;
4470       const char *p = IDENTIFIER_POINTER (TREE_VALUE (args));
4471       int len = strlen (p);
4472       enum machine_mode mode = VOIDmode;
4473       tree typefm;
4474       bool valid_mode;
4475
4476       if (len > 4 && p[0] == '_' && p[1] == '_'
4477           && p[len - 1] == '_' && p[len - 2] == '_')
4478         {
4479           char *newp = (char *) alloca (len - 1);
4480
4481           strcpy (newp, &p[2]);
4482           newp[len - 4] = '\0';
4483           p = newp;
4484         }
4485
4486       /* Change this type to have a type with the specified mode.
4487          First check for the special modes.  */
4488       if (!strcmp (p, "byte"))
4489         mode = byte_mode;
4490       else if (!strcmp (p, "word"))
4491         mode = word_mode;
4492       else if (!strcmp (p, "pointer"))
4493         mode = ptr_mode;
4494       else
4495         for (j = 0; j < NUM_MACHINE_MODES; j++)
4496           if (!strcmp (p, GET_MODE_NAME (j)))
4497             {
4498               mode = (enum machine_mode) j;
4499               break;
4500             }
4501
4502       if (mode == VOIDmode)
4503         {
4504           error ("unknown machine mode %qs", p);
4505           return NULL_TREE;
4506         }
4507
4508       valid_mode = false;
4509       switch (GET_MODE_CLASS (mode))
4510         {
4511         case MODE_INT:
4512         case MODE_PARTIAL_INT:
4513         case MODE_FLOAT:
4514         case MODE_DECIMAL_FLOAT:
4515           valid_mode = targetm.scalar_mode_supported_p (mode);
4516           break;
4517
4518         case MODE_COMPLEX_INT:
4519         case MODE_COMPLEX_FLOAT:
4520           valid_mode = targetm.scalar_mode_supported_p (GET_MODE_INNER (mode));
4521           break;
4522
4523         case MODE_VECTOR_INT:
4524         case MODE_VECTOR_FLOAT:
4525           warning (OPT_Wattributes, "specifying vector types with "
4526                    "__attribute__ ((mode)) is deprecated");
4527           warning (OPT_Wattributes,
4528                    "use __attribute__ ((vector_size)) instead");
4529           valid_mode = vector_mode_valid_p (mode);
4530           break;
4531
4532         default:
4533           break;
4534         }
4535       if (!valid_mode)
4536         {
4537           error ("unable to emulate %qs", p);
4538           return NULL_TREE;
4539         }
4540
4541       if (POINTER_TYPE_P (type))
4542         {
4543           tree (*fn)(tree, enum machine_mode, bool);
4544
4545           if (!targetm.valid_pointer_mode (mode))
4546             {
4547               error ("invalid pointer mode %qs", p);
4548               return NULL_TREE;
4549             }
4550
4551           if (TREE_CODE (type) == POINTER_TYPE)
4552             fn = build_pointer_type_for_mode;
4553           else
4554             fn = build_reference_type_for_mode;
4555           typefm = fn (TREE_TYPE (type), mode, false);
4556         }
4557       else
4558         typefm = lang_hooks.types.type_for_mode (mode, TYPE_UNSIGNED (type));
4559
4560       if (typefm == NULL_TREE)
4561         {
4562           error ("no data type for mode %qs", p);
4563           return NULL_TREE;
4564         }
4565       else if (TREE_CODE (type) == ENUMERAL_TYPE)
4566         {
4567           /* For enumeral types, copy the precision from the integer
4568              type returned above.  If not an INTEGER_TYPE, we can't use
4569              this mode for this type.  */
4570           if (TREE_CODE (typefm) != INTEGER_TYPE)
4571             {
4572               error ("cannot use mode %qs for enumeral types", p);
4573               return NULL_TREE;
4574             }
4575
4576           if (flags & ATTR_FLAG_TYPE_IN_PLACE)
4577             {
4578               TYPE_PRECISION (type) = TYPE_PRECISION (typefm);
4579               typefm = type;
4580             }
4581           else
4582             {
4583               /* We cannot build a type variant, as there's code that assumes
4584                  that TYPE_MAIN_VARIANT has the same mode.  This includes the
4585                  debug generators.  Instead, create a subrange type.  This
4586                  results in all of the enumeral values being emitted only once
4587                  in the original, and the subtype gets them by reference.  */
4588               if (TYPE_UNSIGNED (type))
4589                 typefm = make_unsigned_type (TYPE_PRECISION (typefm));
4590               else
4591                 typefm = make_signed_type (TYPE_PRECISION (typefm));
4592               TREE_TYPE (typefm) = type;
4593             }
4594         }
4595       else if (VECTOR_MODE_P (mode)
4596                ? TREE_CODE (type) != TREE_CODE (TREE_TYPE (typefm))
4597                : TREE_CODE (type) != TREE_CODE (typefm))
4598         {
4599           error ("mode %qs applied to inappropriate type", p);
4600           return NULL_TREE;
4601         }
4602
4603       *node = typefm;
4604     }
4605
4606   return NULL_TREE;
4607 }
4608
4609 /* Handle a "section" attribute; arguments as in
4610    struct attribute_spec.handler.  */
4611
4612 static tree
4613 handle_section_attribute (tree *node, tree ARG_UNUSED (name), tree args,
4614                           int ARG_UNUSED (flags), bool *no_add_attrs)
4615 {
4616   tree decl = *node;
4617
4618   if (targetm.have_named_sections)
4619     {
4620       user_defined_section_attribute = true;
4621
4622       if ((TREE_CODE (decl) == FUNCTION_DECL
4623            || TREE_CODE (decl) == VAR_DECL)
4624           && TREE_CODE (TREE_VALUE (args)) == STRING_CST)
4625         {
4626           if (TREE_CODE (decl) == VAR_DECL
4627               && current_function_decl != NULL_TREE
4628               && !TREE_STATIC (decl))
4629             {
4630               error ("%Jsection attribute cannot be specified for "
4631                      "local variables", decl);
4632               *no_add_attrs = true;
4633             }
4634
4635           /* The decl may have already been given a section attribute
4636              from a previous declaration.  Ensure they match.  */
4637           else if (DECL_SECTION_NAME (decl) != NULL_TREE
4638                    && strcmp (TREE_STRING_POINTER (DECL_SECTION_NAME (decl)),
4639                               TREE_STRING_POINTER (TREE_VALUE (args))) != 0)
4640             {
4641               error ("section of %q+D conflicts with previous declaration",
4642                      *node);
4643               *no_add_attrs = true;
4644             }
4645           else
4646             DECL_SECTION_NAME (decl) = TREE_VALUE (args);
4647         }
4648       else
4649         {
4650           error ("section attribute not allowed for %q+D", *node);
4651           *no_add_attrs = true;
4652         }
4653     }
4654   else
4655     {
4656       error ("%Jsection attributes are not supported for this target", *node);
4657       *no_add_attrs = true;
4658     }
4659
4660   return NULL_TREE;
4661 }
4662
4663 /* Handle a "aligned" attribute; arguments as in
4664    struct attribute_spec.handler.  */
4665
4666 static tree
4667 handle_aligned_attribute (tree *node, tree ARG_UNUSED (name), tree args,
4668                           int flags, bool *no_add_attrs)
4669 {
4670   tree decl = NULL_TREE;
4671   tree *type = NULL;
4672   int is_type = 0;
4673   tree align_expr = (args ? TREE_VALUE (args)
4674                      : size_int (BIGGEST_ALIGNMENT / BITS_PER_UNIT));
4675   int i;
4676
4677   if (DECL_P (*node))
4678     {
4679       decl = *node;
4680       type = &TREE_TYPE (decl);
4681       is_type = TREE_CODE (*node) == TYPE_DECL;
4682     }
4683   else if (TYPE_P (*node))
4684     type = node, is_type = 1;
4685
4686   if (TREE_CODE (align_expr) != INTEGER_CST)
4687     {
4688       error ("requested alignment is not a constant");
4689       *no_add_attrs = true;
4690     }
4691   else if ((i = tree_log2 (align_expr)) == -1)
4692     {
4693       error ("requested alignment is not a power of 2");
4694       *no_add_attrs = true;
4695     }
4696   else if (i > HOST_BITS_PER_INT - 2)
4697     {
4698       error ("requested alignment is too large");
4699       *no_add_attrs = true;
4700     }
4701   else if (is_type)
4702     {
4703       /* If we have a TYPE_DECL, then copy the type, so that we
4704          don't accidentally modify a builtin type.  See pushdecl.  */
4705       if (decl && TREE_TYPE (decl) != error_mark_node
4706           && DECL_ORIGINAL_TYPE (decl) == NULL_TREE)
4707         {
4708           tree tt = TREE_TYPE (decl);
4709           *type = build_variant_type_copy (*type);
4710           DECL_ORIGINAL_TYPE (decl) = tt;
4711           TYPE_NAME (*type) = decl;
4712           TREE_USED (*type) = TREE_USED (decl);
4713           TREE_TYPE (decl) = *type;
4714         }
4715       else if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
4716         *type = build_variant_type_copy (*type);
4717
4718       TYPE_ALIGN (*type) = (1 << i) * BITS_PER_UNIT;
4719       TYPE_USER_ALIGN (*type) = 1;
4720     }
4721   else if (TREE_CODE (decl) != VAR_DECL
4722            && TREE_CODE (decl) != FIELD_DECL)
4723     {
4724       error ("alignment may not be specified for %q+D", decl);
4725       *no_add_attrs = true;
4726     }
4727   else
4728     {
4729       DECL_ALIGN (decl) = (1 << i) * BITS_PER_UNIT;
4730       DECL_USER_ALIGN (decl) = 1;
4731     }
4732
4733   return NULL_TREE;
4734 }
4735
4736 /* Handle a "weak" attribute; arguments as in
4737    struct attribute_spec.handler.  */
4738
4739 static tree
4740 handle_weak_attribute (tree *node, tree name,
4741                        tree ARG_UNUSED (args),
4742                        int ARG_UNUSED (flags),
4743                        bool * ARG_UNUSED (no_add_attrs))
4744 {
4745   if (TREE_CODE (*node) == FUNCTION_DECL
4746       || TREE_CODE (*node) == VAR_DECL)
4747     declare_weak (*node);
4748   else
4749     warning (OPT_Wattributes, "%qE attribute ignored", name);
4750
4751
4752   return NULL_TREE;
4753 }
4754
4755 /* Handle an "alias" attribute; arguments as in
4756    struct attribute_spec.handler.  */
4757
4758 static tree
4759 handle_alias_attribute (tree *node, tree name, tree args,
4760                         int ARG_UNUSED (flags), bool *no_add_attrs)
4761 {
4762   tree decl = *node;
4763
4764   if ((TREE_CODE (decl) == FUNCTION_DECL && DECL_INITIAL (decl))
4765       || (TREE_CODE (decl) != FUNCTION_DECL
4766           && TREE_PUBLIC (decl) && !DECL_EXTERNAL (decl))
4767       /* A static variable declaration is always a tentative definition,
4768          but the alias is a non-tentative definition which overrides.  */
4769       || (TREE_CODE (decl) != FUNCTION_DECL
4770           && ! TREE_PUBLIC (decl) && DECL_INITIAL (decl)))
4771     {
4772       error ("%q+D defined both normally and as an alias", decl);
4773       *no_add_attrs = true;
4774     }
4775
4776   /* Note that the very first time we process a nested declaration,
4777      decl_function_context will not be set.  Indeed, *would* never
4778      be set except for the DECL_INITIAL/DECL_EXTERNAL frobbery that
4779      we do below.  After such frobbery, pushdecl would set the context.
4780      In any case, this is never what we want.  */
4781   else if (decl_function_context (decl) == 0 && current_function_decl == NULL)
4782     {
4783       tree id;
4784
4785       id = TREE_VALUE (args);
4786       if (TREE_CODE (id) != STRING_CST)
4787         {
4788           error ("alias argument not a string");
4789           *no_add_attrs = true;
4790           return NULL_TREE;
4791         }
4792       id = get_identifier (TREE_STRING_POINTER (id));
4793       /* This counts as a use of the object pointed to.  */
4794       TREE_USED (id) = 1;
4795
4796       if (TREE_CODE (decl) == FUNCTION_DECL)
4797         DECL_INITIAL (decl) = error_mark_node;
4798       else
4799         {
4800           if (lookup_attribute ("weakref", DECL_ATTRIBUTES (decl)))
4801             DECL_EXTERNAL (decl) = 1;
4802           else
4803             DECL_EXTERNAL (decl) = 0;
4804           TREE_STATIC (decl) = 1;
4805         }
4806     }
4807   else
4808     {
4809       warning (OPT_Wattributes, "%qE attribute ignored", name);
4810       *no_add_attrs = true;
4811     }
4812
4813   return NULL_TREE;
4814 }
4815
4816 /* Handle a "weakref" attribute; arguments as in struct
4817    attribute_spec.handler.  */
4818
4819 static tree
4820 handle_weakref_attribute (tree *node, tree ARG_UNUSED (name), tree args,
4821                           int flags, bool *no_add_attrs)
4822 {
4823   tree attr = NULL_TREE;
4824
4825   /* We must ignore the attribute when it is associated with
4826      local-scoped decls, since attribute alias is ignored and many
4827      such symbols do not even have a DECL_WEAK field.  */
4828   if (decl_function_context (*node) || current_function_decl)
4829     {
4830       warning (OPT_Wattributes, "%qE attribute ignored", name);
4831       *no_add_attrs = true;
4832       return NULL_TREE;
4833     }
4834
4835   /* The idea here is that `weakref("name")' mutates into `weakref,
4836      alias("name")', and weakref without arguments, in turn,
4837      implicitly adds weak. */
4838
4839   if (args)
4840     {
4841       attr = tree_cons (get_identifier ("alias"), args, attr);
4842       attr = tree_cons (get_identifier ("weakref"), NULL_TREE, attr);
4843
4844       *no_add_attrs = true;
4845
4846       decl_attributes (node, attr, flags);
4847     }
4848   else
4849     {
4850       if (lookup_attribute ("alias", DECL_ATTRIBUTES (*node)))
4851         error ("%Jweakref attribute must appear before alias attribute",
4852                *node);
4853
4854       /* Can't call declare_weak because it wants this to be TREE_PUBLIC,
4855          and that isn't supported; and because it wants to add it to
4856          the list of weak decls, which isn't helpful.  */
4857       DECL_WEAK (*node) = 1;
4858     }
4859
4860   return NULL_TREE;
4861 }
4862
4863 /* Handle an "visibility" attribute; arguments as in
4864    struct attribute_spec.handler.  */
4865
4866 static tree
4867 handle_visibility_attribute (tree *node, tree name, tree args,
4868                              int ARG_UNUSED (flags),
4869                              bool *ARG_UNUSED (no_add_attrs))
4870 {
4871   tree decl = *node;
4872   tree id = TREE_VALUE (args);
4873   enum symbol_visibility vis;
4874
4875   if (TYPE_P (*node))
4876     {
4877       if (TREE_CODE (*node) == ENUMERAL_TYPE)
4878         /* OK */;
4879       else if (TREE_CODE (*node) != RECORD_TYPE && TREE_CODE (*node) != UNION_TYPE)
4880         {
4881           warning (OPT_Wattributes, "%qE attribute ignored on non-class types",
4882                    name);
4883           return NULL_TREE;
4884         }
4885       else if (TYPE_FIELDS (*node))
4886         {
4887           error ("%qE attribute ignored because %qT is already defined",
4888                  name, *node);
4889           return NULL_TREE;
4890         }
4891     }
4892   else if (decl_function_context (decl) != 0 || !TREE_PUBLIC (decl))
4893     {
4894       warning (OPT_Wattributes, "%qE attribute ignored", name);
4895       return NULL_TREE;
4896     }
4897
4898   if (TREE_CODE (id) != STRING_CST)
4899     {
4900       error ("visibility argument not a string");
4901       return NULL_TREE;
4902     }
4903
4904   /*  If this is a type, set the visibility on the type decl.  */
4905   if (TYPE_P (decl))
4906     {
4907       decl = TYPE_NAME (decl);
4908       if (!decl)
4909         return NULL_TREE;
4910       if (TREE_CODE (decl) == IDENTIFIER_NODE)
4911         {
4912            warning (OPT_Wattributes, "%qE attribute ignored on types",
4913                     name);
4914            return NULL_TREE;
4915         }
4916     }
4917
4918   if (strcmp (TREE_STRING_POINTER (id), "default") == 0)
4919     vis = VISIBILITY_DEFAULT;
4920   else if (strcmp (TREE_STRING_POINTER (id), "internal") == 0)
4921     vis = VISIBILITY_INTERNAL;
4922   else if (strcmp (TREE_STRING_POINTER (id), "hidden") == 0)
4923     vis = VISIBILITY_HIDDEN;
4924   else if (strcmp (TREE_STRING_POINTER (id), "protected") == 0)
4925     vis = VISIBILITY_PROTECTED;
4926   else
4927     {
4928       error ("visibility argument must be one of \"default\", \"hidden\", \"protected\" or \"internal\"");
4929       vis = VISIBILITY_DEFAULT;
4930     }
4931
4932   if (DECL_VISIBILITY_SPECIFIED (decl)
4933       && vis != DECL_VISIBILITY (decl)
4934       && lookup_attribute ("visibility", (TYPE_P (*node)
4935                                           ? TYPE_ATTRIBUTES (*node)
4936                                           : DECL_ATTRIBUTES (decl))))
4937     error ("%qD redeclared with different visibility", decl);
4938
4939   DECL_VISIBILITY (decl) = vis;
4940   DECL_VISIBILITY_SPECIFIED (decl) = 1;
4941
4942   /* Go ahead and attach the attribute to the node as well.  This is needed
4943      so we can determine whether we have VISIBILITY_DEFAULT because the
4944      visibility was not specified, or because it was explicitly overridden
4945      from the containing scope.  */
4946
4947   return NULL_TREE;
4948 }
4949
4950 /* Determine the ELF symbol visibility for DECL, which is either a
4951    variable or a function.  It is an error to use this function if a
4952    definition of DECL is not available in this translation unit.
4953    Returns true if the final visibility has been determined by this
4954    function; false if the caller is free to make additional
4955    modifications.  */
4956
4957 bool
4958 c_determine_visibility (tree decl)
4959 {
4960   gcc_assert (TREE_CODE (decl) == VAR_DECL
4961               || TREE_CODE (decl) == FUNCTION_DECL);
4962
4963   /* If the user explicitly specified the visibility with an
4964      attribute, honor that.  DECL_VISIBILITY will have been set during
4965      the processing of the attribute.  We check for an explicit
4966      attribute, rather than just checking DECL_VISIBILITY_SPECIFIED,
4967      to distinguish the use of an attribute from the use of a "#pragma
4968      GCC visibility push(...)"; in the latter case we still want other
4969      considerations to be able to overrule the #pragma.  */
4970   if (lookup_attribute ("visibility", DECL_ATTRIBUTES (decl)))
4971     return true;
4972
4973   /* Anything that is exported must have default visibility.  */
4974   if (TARGET_DLLIMPORT_DECL_ATTRIBUTES
4975       && lookup_attribute ("dllexport", DECL_ATTRIBUTES (decl)))
4976     {
4977       DECL_VISIBILITY (decl) = VISIBILITY_DEFAULT;
4978       DECL_VISIBILITY_SPECIFIED (decl) = 1;
4979       return true;
4980     }
4981
4982   /* Set default visibility to whatever the user supplied with
4983      visibility_specified depending on #pragma GCC visibility.  */
4984   if (!DECL_VISIBILITY_SPECIFIED (decl))
4985     {
4986       DECL_VISIBILITY (decl) = default_visibility;
4987       DECL_VISIBILITY_SPECIFIED (decl) = visibility_options.inpragma;
4988     }
4989   return false;
4990 }
4991
4992 /* Handle an "tls_model" attribute; arguments as in
4993    struct attribute_spec.handler.  */
4994
4995 static tree
4996 handle_tls_model_attribute (tree *node, tree name, tree args,
4997                             int ARG_UNUSED (flags), bool *no_add_attrs)
4998 {
4999   tree id;
5000   tree decl = *node;
5001   enum tls_model kind;
5002
5003   *no_add_attrs = true;
5004
5005   if (!DECL_THREAD_LOCAL_P (decl))
5006     {
5007       warning (OPT_Wattributes, "%qE attribute ignored", name);
5008       return NULL_TREE;
5009     }
5010
5011   kind = DECL_TLS_MODEL (decl);
5012   id = TREE_VALUE (args);
5013   if (TREE_CODE (id) != STRING_CST)
5014     {
5015       error ("tls_model argument not a string");
5016       return NULL_TREE;
5017     }
5018
5019   if (!strcmp (TREE_STRING_POINTER (id), "local-exec"))
5020     kind = TLS_MODEL_LOCAL_EXEC;
5021   else if (!strcmp (TREE_STRING_POINTER (id), "initial-exec"))
5022     kind = TLS_MODEL_INITIAL_EXEC;
5023   else if (!strcmp (TREE_STRING_POINTER (id), "local-dynamic"))
5024     kind = optimize ? TLS_MODEL_LOCAL_DYNAMIC : TLS_MODEL_GLOBAL_DYNAMIC;
5025   else if (!strcmp (TREE_STRING_POINTER (id), "global-dynamic"))
5026     kind = TLS_MODEL_GLOBAL_DYNAMIC;
5027   else
5028     error ("tls_model argument must be one of \"local-exec\", \"initial-exec\", \"local-dynamic\" or \"global-dynamic\"");
5029
5030   DECL_TLS_MODEL (decl) = kind;
5031   return NULL_TREE;
5032 }
5033
5034 /* Handle a "no_instrument_function" attribute; arguments as in
5035    struct attribute_spec.handler.  */
5036
5037 static tree
5038 handle_no_instrument_function_attribute (tree *node, tree name,
5039                                          tree ARG_UNUSED (args),
5040                                          int ARG_UNUSED (flags),
5041                                          bool *no_add_attrs)
5042 {
5043   tree decl = *node;
5044
5045   if (TREE_CODE (decl) != FUNCTION_DECL)
5046     {
5047       error ("%J%qE attribute applies only to functions", decl, name);
5048       *no_add_attrs = true;
5049     }
5050   else if (DECL_INITIAL (decl))
5051     {
5052       error ("%Jcan%'t set %qE attribute after definition", decl, name);
5053       *no_add_attrs = true;
5054     }
5055   else
5056     DECL_NO_INSTRUMENT_FUNCTION_ENTRY_EXIT (decl) = 1;
5057
5058   return NULL_TREE;
5059 }
5060
5061 /* Handle a "malloc" attribute; arguments as in
5062    struct attribute_spec.handler.  */
5063
5064 static tree
5065 handle_malloc_attribute (tree *node, tree name, tree ARG_UNUSED (args),
5066                          int ARG_UNUSED (flags), bool *no_add_attrs)
5067 {
5068   if (TREE_CODE (*node) == FUNCTION_DECL
5069       && POINTER_TYPE_P (TREE_TYPE (TREE_TYPE (*node))))
5070     DECL_IS_MALLOC (*node) = 1;
5071   else
5072     {
5073       warning (OPT_Wattributes, "%qE attribute ignored", name);
5074       *no_add_attrs = true;
5075     }
5076
5077   return NULL_TREE;
5078 }
5079
5080 /* Handle a "returns_twice" attribute; arguments as in
5081    struct attribute_spec.handler.  */
5082
5083 static tree
5084 handle_returns_twice_attribute (tree *node, tree name, tree ARG_UNUSED (args),
5085                          int ARG_UNUSED (flags), bool *no_add_attrs)
5086 {
5087   if (TREE_CODE (*node) == FUNCTION_DECL)
5088     DECL_IS_RETURNS_TWICE (*node) = 1;
5089   else
5090     {
5091       warning (OPT_Wattributes, "%qE attribute ignored", name);
5092       *no_add_attrs = true;
5093     }
5094
5095   return NULL_TREE;
5096 }
5097
5098 /* Handle a "no_limit_stack" attribute; arguments as in
5099    struct attribute_spec.handler.  */
5100
5101 static tree
5102 handle_no_limit_stack_attribute (tree *node, tree name,
5103                                  tree ARG_UNUSED (args),
5104                                  int ARG_UNUSED (flags),
5105                                  bool *no_add_attrs)
5106 {
5107   tree decl = *node;
5108
5109   if (TREE_CODE (decl) != FUNCTION_DECL)
5110     {
5111       error ("%J%qE attribute applies only to functions", decl, name);
5112       *no_add_attrs = true;
5113     }
5114   else if (DECL_INITIAL (decl))
5115     {
5116       error ("%Jcan%'t set %qE attribute after definition", decl, name);
5117       *no_add_attrs = true;
5118     }
5119   else
5120     DECL_NO_LIMIT_STACK (decl) = 1;
5121
5122   return NULL_TREE;
5123 }
5124
5125 /* Handle a "pure" attribute; arguments as in
5126    struct attribute_spec.handler.  */
5127
5128 static tree
5129 handle_pure_attribute (tree *node, tree name, tree ARG_UNUSED (args),
5130                        int ARG_UNUSED (flags), bool *no_add_attrs)
5131 {
5132   if (TREE_CODE (*node) == FUNCTION_DECL)
5133     DECL_IS_PURE (*node) = 1;
5134   /* ??? TODO: Support types.  */
5135   else
5136     {
5137       warning (OPT_Wattributes, "%qE attribute ignored", name);
5138       *no_add_attrs = true;
5139     }
5140
5141   return NULL_TREE;
5142 }
5143
5144 /* Handle a "no vops" attribute; arguments as in
5145    struct attribute_spec.handler.  */
5146
5147 static tree
5148 handle_novops_attribute (tree *node, tree ARG_UNUSED (name),
5149                          tree ARG_UNUSED (args), int ARG_UNUSED (flags),
5150                          bool *ARG_UNUSED (no_add_attrs))
5151 {
5152   gcc_assert (TREE_CODE (*node) == FUNCTION_DECL);
5153   DECL_IS_NOVOPS (*node) = 1;
5154   return NULL_TREE;
5155 }
5156
5157 /* Handle a "deprecated" attribute; arguments as in
5158    struct attribute_spec.handler.  */
5159
5160 static tree
5161 handle_deprecated_attribute (tree *node, tree name,
5162                              tree ARG_UNUSED (args), int flags,
5163                              bool *no_add_attrs)
5164 {
5165   tree type = NULL_TREE;
5166   int warn = 0;
5167   tree what = NULL_TREE;
5168
5169   if (DECL_P (*node))
5170     {
5171       tree decl = *node;
5172       type = TREE_TYPE (decl);
5173
5174       if (TREE_CODE (decl) == TYPE_DECL
5175           || TREE_CODE (decl) == PARM_DECL
5176           || TREE_CODE (decl) == VAR_DECL
5177           || TREE_CODE (decl) == FUNCTION_DECL
5178           || TREE_CODE (decl) == FIELD_DECL)
5179         TREE_DEPRECATED (decl) = 1;
5180       else
5181         warn = 1;
5182     }
5183   else if (TYPE_P (*node))
5184     {
5185       if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
5186         *node = build_variant_type_copy (*node);
5187       TREE_DEPRECATED (*node) = 1;
5188       type = *node;
5189     }
5190   else
5191     warn = 1;
5192
5193   if (warn)
5194     {
5195       *no_add_attrs = true;
5196       if (type && TYPE_NAME (type))
5197         {
5198           if (TREE_CODE (TYPE_NAME (type)) == IDENTIFIER_NODE)
5199             what = TYPE_NAME (*node);
5200           else if (TREE_CODE (TYPE_NAME (type)) == TYPE_DECL
5201                    && DECL_NAME (TYPE_NAME (type)))
5202             what = DECL_NAME (TYPE_NAME (type));
5203         }
5204       if (what)
5205         warning (OPT_Wattributes, "%qE attribute ignored for %qE", name, what);
5206       else
5207         warning (OPT_Wattributes, "%qE attribute ignored", name);
5208     }
5209
5210   return NULL_TREE;
5211 }
5212
5213 /* Handle a "vector_size" attribute; arguments as in
5214    struct attribute_spec.handler.  */
5215
5216 static tree
5217 handle_vector_size_attribute (tree *node, tree name, tree args,
5218                               int ARG_UNUSED (flags),
5219                               bool *no_add_attrs)
5220 {
5221   unsigned HOST_WIDE_INT vecsize, nunits;
5222   enum machine_mode orig_mode;
5223   tree type = *node, new_type, size;
5224
5225   *no_add_attrs = true;
5226
5227   size = TREE_VALUE (args);
5228
5229   if (!host_integerp (size, 1))
5230     {
5231       warning (OPT_Wattributes, "%qE attribute ignored", name);
5232       return NULL_TREE;
5233     }
5234
5235   /* Get the vector size (in bytes).  */
5236   vecsize = tree_low_cst (size, 1);
5237
5238   /* We need to provide for vector pointers, vector arrays, and
5239      functions returning vectors.  For example:
5240
5241        __attribute__((vector_size(16))) short *foo;
5242
5243      In this case, the mode is SI, but the type being modified is
5244      HI, so we need to look further.  */
5245
5246   while (POINTER_TYPE_P (type)
5247          || TREE_CODE (type) == FUNCTION_TYPE
5248          || TREE_CODE (type) == METHOD_TYPE
5249          || TREE_CODE (type) == ARRAY_TYPE)
5250     type = TREE_TYPE (type);
5251
5252   /* Get the mode of the type being modified.  */
5253   orig_mode = TYPE_MODE (type);
5254
5255   if (TREE_CODE (type) == RECORD_TYPE
5256       || (!SCALAR_FLOAT_MODE_P (orig_mode)
5257           && GET_MODE_CLASS (orig_mode) != MODE_INT)
5258       || !host_integerp (TYPE_SIZE_UNIT (type), 1))
5259     {
5260       error ("invalid vector type for attribute %qE", name);
5261       return NULL_TREE;
5262     }
5263
5264   if (vecsize % tree_low_cst (TYPE_SIZE_UNIT (type), 1))
5265     {
5266       error ("vector size not an integral multiple of component size");
5267       return NULL;
5268     }
5269
5270   if (vecsize == 0)
5271     {
5272       error ("zero vector size");
5273       return NULL;
5274     }
5275
5276   /* Calculate how many units fit in the vector.  */
5277   nunits = vecsize / tree_low_cst (TYPE_SIZE_UNIT (type), 1);
5278   if (nunits & (nunits - 1))
5279     {
5280       error ("number of components of the vector not a power of two");
5281       return NULL_TREE;
5282     }
5283
5284   new_type = build_vector_type (type, nunits);
5285
5286   /* Build back pointers if needed.  */
5287   *node = reconstruct_complex_type (*node, new_type);
5288
5289   return NULL_TREE;
5290 }
5291
5292 /* Handle the "nonnull" attribute.  */
5293 static tree
5294 handle_nonnull_attribute (tree *node, tree ARG_UNUSED (name),
5295                           tree args, int ARG_UNUSED (flags),
5296                           bool *no_add_attrs)
5297 {
5298   tree type = *node;
5299   unsigned HOST_WIDE_INT attr_arg_num;
5300
5301   /* If no arguments are specified, all pointer arguments should be
5302      non-null.  Verify a full prototype is given so that the arguments
5303      will have the correct types when we actually check them later.  */
5304   if (!args)
5305     {
5306       if (!TYPE_ARG_TYPES (type))
5307         {
5308           error ("nonnull attribute without arguments on a non-prototype");
5309           *no_add_attrs = true;
5310         }
5311       return NULL_TREE;
5312     }
5313
5314   /* Argument list specified.  Verify that each argument number references
5315      a pointer argument.  */
5316   for (attr_arg_num = 1; args; args = TREE_CHAIN (args))
5317     {
5318       tree argument;
5319       unsigned HOST_WIDE_INT arg_num = 0, ck_num;
5320
5321       if (!get_nonnull_operand (TREE_VALUE (args), &arg_num))
5322         {
5323           error ("nonnull argument has invalid operand number (argument %lu)",
5324                  (unsigned long) attr_arg_num);
5325           *no_add_attrs = true;
5326           return NULL_TREE;
5327         }
5328
5329       argument = TYPE_ARG_TYPES (type);
5330       if (argument)
5331         {
5332           for (ck_num = 1; ; ck_num++)
5333             {
5334               if (!argument || ck_num == arg_num)
5335                 break;
5336               argument = TREE_CHAIN (argument);
5337             }
5338
5339           if (!argument
5340               || TREE_CODE (TREE_VALUE (argument)) == VOID_TYPE)
5341             {
5342               error ("nonnull argument with out-of-range operand number (argument %lu, operand %lu)",
5343                      (unsigned long) attr_arg_num, (unsigned long) arg_num);
5344               *no_add_attrs = true;
5345               return NULL_TREE;
5346             }
5347
5348           if (TREE_CODE (TREE_VALUE (argument)) != POINTER_TYPE)
5349             {
5350               error ("nonnull argument references non-pointer operand (argument %lu, operand %lu)",
5351                    (unsigned long) attr_arg_num, (unsigned long) arg_num);
5352               *no_add_attrs = true;
5353               return NULL_TREE;
5354             }
5355         }
5356     }
5357
5358   return NULL_TREE;
5359 }
5360
5361 /* Check the argument list of a function call for null in argument slots
5362    that are marked as requiring a non-null pointer argument.  */
5363
5364 static void
5365 check_function_nonnull (tree attrs, tree params)
5366 {
5367   tree a, args, param;
5368   int param_num;
5369
5370   for (a = attrs; a; a = TREE_CHAIN (a))
5371     {
5372       if (is_attribute_p ("nonnull", TREE_PURPOSE (a)))
5373         {
5374           args = TREE_VALUE (a);
5375
5376           /* Walk the argument list.  If we encounter an argument number we
5377              should check for non-null, do it.  If the attribute has no args,
5378              then every pointer argument is checked (in which case the check
5379              for pointer type is done in check_nonnull_arg).  */
5380           for (param = params, param_num = 1; ;
5381                param_num++, param = TREE_CHAIN (param))
5382             {
5383               if (!param)
5384         break;
5385               if (!args || nonnull_check_p (args, param_num))
5386         check_function_arguments_recurse (check_nonnull_arg, NULL,
5387                                           TREE_VALUE (param),
5388                                           param_num);
5389             }
5390         }
5391     }
5392 }
5393
5394 /* Check that the Nth argument of a function call (counting backwards
5395    from the end) is a (pointer)0.  */
5396
5397 static void
5398 check_function_sentinel (tree attrs, tree params, tree typelist)
5399 {
5400   tree attr = lookup_attribute ("sentinel", attrs);
5401
5402   if (attr)
5403     {
5404       /* Skip over the named arguments.  */
5405       while (typelist && params)
5406       {
5407         typelist = TREE_CHAIN (typelist);
5408         params = TREE_CHAIN (params);
5409       }
5410
5411       if (typelist || !params)
5412         warning (OPT_Wformat,
5413                  "not enough variable arguments to fit a sentinel");
5414       else
5415         {
5416           tree sentinel, end;
5417           unsigned pos = 0;
5418
5419           if (TREE_VALUE (attr))
5420             {
5421               tree p = TREE_VALUE (TREE_VALUE (attr));
5422               pos = TREE_INT_CST_LOW (p);
5423             }
5424
5425           sentinel = end = params;
5426
5427           /* Advance `end' ahead of `sentinel' by `pos' positions.  */
5428           while (pos > 0 && TREE_CHAIN (end))
5429             {
5430               pos--;
5431               end = TREE_CHAIN (end);
5432             }
5433           if (pos > 0)
5434             {
5435               warning (OPT_Wformat,
5436                        "not enough variable arguments to fit a sentinel");
5437               return;
5438             }
5439
5440           /* Now advance both until we find the last parameter.  */
5441           while (TREE_CHAIN (end))
5442             {
5443               end = TREE_CHAIN (end);
5444               sentinel = TREE_CHAIN (sentinel);
5445             }
5446
5447           /* Validate the sentinel.  */
5448           if ((!POINTER_TYPE_P (TREE_TYPE (TREE_VALUE (sentinel)))
5449                || !integer_zerop (TREE_VALUE (sentinel)))
5450               /* Although __null (in C++) is only an integer we allow it
5451                  nevertheless, as we are guaranteed that it's exactly
5452                  as wide as a pointer, and we don't want to force
5453                  users to cast the NULL they have written there.
5454                  We warn with -Wstrict-null-sentinel, though.  */
5455               && (warn_strict_null_sentinel
5456                   || null_node != TREE_VALUE (sentinel)))
5457             warning (OPT_Wformat, "missing sentinel in function call");
5458         }
5459     }
5460 }
5461
5462 /* Helper for check_function_nonnull; given a list of operands which
5463    must be non-null in ARGS, determine if operand PARAM_NUM should be
5464    checked.  */
5465
5466 static bool
5467 nonnull_check_p (tree args, unsigned HOST_WIDE_INT param_num)
5468 {
5469   unsigned HOST_WIDE_INT arg_num = 0;
5470
5471   for (; args; args = TREE_CHAIN (args))
5472     {
5473       bool found = get_nonnull_operand (TREE_VALUE (args), &arg_num);
5474
5475       gcc_assert (found);
5476
5477       if (arg_num == param_num)
5478         return true;
5479     }
5480   return false;
5481 }
5482
5483 /* Check that the function argument PARAM (which is operand number
5484    PARAM_NUM) is non-null.  This is called by check_function_nonnull
5485    via check_function_arguments_recurse.  */
5486
5487 static void
5488 check_nonnull_arg (void * ARG_UNUSED (ctx), tree param,
5489                    unsigned HOST_WIDE_INT param_num)
5490 {
5491   /* Just skip checking the argument if it's not a pointer.  This can
5492      happen if the "nonnull" attribute was given without an operand
5493      list (which means to check every pointer argument).  */
5494
5495   if (TREE_CODE (TREE_TYPE (param)) != POINTER_TYPE)
5496     return;
5497
5498   if (integer_zerop (param))
5499     warning (OPT_Wnonnull, "null argument where non-null required "
5500              "(argument %lu)", (unsigned long) param_num);
5501 }
5502
5503 /* Helper for nonnull attribute handling; fetch the operand number
5504    from the attribute argument list.  */
5505
5506 static bool
5507 get_nonnull_operand (tree arg_num_expr, unsigned HOST_WIDE_INT *valp)
5508 {
5509   /* Verify the arg number is a constant.  */
5510   if (TREE_CODE (arg_num_expr) != INTEGER_CST
5511       || TREE_INT_CST_HIGH (arg_num_expr) != 0)
5512     return false;
5513
5514   *valp = TREE_INT_CST_LOW (arg_num_expr);
5515   return true;
5516 }
5517
5518 /* Handle a "nothrow" attribute; arguments as in
5519    struct attribute_spec.handler.  */
5520
5521 static tree
5522 handle_nothrow_attribute (tree *node, tree name, tree ARG_UNUSED (args),
5523                           int ARG_UNUSED (flags), bool *no_add_attrs)
5524 {
5525   if (TREE_CODE (*node) == FUNCTION_DECL)
5526     TREE_NOTHROW (*node) = 1;
5527   /* ??? TODO: Support types.  */
5528   else
5529     {
5530       warning (OPT_Wattributes, "%qE attribute ignored", name);
5531       *no_add_attrs = true;
5532     }
5533
5534   return NULL_TREE;
5535 }
5536
5537 /* Handle a "cleanup" attribute; arguments as in
5538    struct attribute_spec.handler.  */
5539
5540 static tree
5541 handle_cleanup_attribute (tree *node, tree name, tree args,
5542                           int ARG_UNUSED (flags), bool *no_add_attrs)
5543 {
5544   tree decl = *node;
5545   tree cleanup_id, cleanup_decl;
5546
5547   /* ??? Could perhaps support cleanups on TREE_STATIC, much like we do
5548      for global destructors in C++.  This requires infrastructure that
5549      we don't have generically at the moment.  It's also not a feature
5550      we'd be missing too much, since we do have attribute constructor.  */
5551   if (TREE_CODE (decl) != VAR_DECL || TREE_STATIC (decl))
5552     {
5553       warning (OPT_Wattributes, "%qE attribute ignored", name);
5554       *no_add_attrs = true;
5555       return NULL_TREE;
5556     }
5557
5558   /* Verify that the argument is a function in scope.  */
5559   /* ??? We could support pointers to functions here as well, if
5560      that was considered desirable.  */
5561   cleanup_id = TREE_VALUE (args);
5562   if (TREE_CODE (cleanup_id) != IDENTIFIER_NODE)
5563     {
5564       error ("cleanup argument not an identifier");
5565       *no_add_attrs = true;
5566       return NULL_TREE;
5567     }
5568   cleanup_decl = lookup_name (cleanup_id);
5569   if (!cleanup_decl || TREE_CODE (cleanup_decl) != FUNCTION_DECL)
5570     {
5571       error ("cleanup argument not a function");
5572       *no_add_attrs = true;
5573       return NULL_TREE;
5574     }
5575
5576   /* That the function has proper type is checked with the
5577      eventual call to build_function_call.  */
5578
5579   return NULL_TREE;
5580 }
5581
5582 /* Handle a "warn_unused_result" attribute.  No special handling.  */
5583
5584 static tree
5585 handle_warn_unused_result_attribute (tree *node, tree name,
5586                                tree ARG_UNUSED (args),
5587                                int ARG_UNUSED (flags), bool *no_add_attrs)
5588 {
5589   /* Ignore the attribute for functions not returning any value.  */
5590   if (VOID_TYPE_P (TREE_TYPE (*node)))
5591     {
5592       warning (OPT_Wattributes, "%qE attribute ignored", name);
5593       *no_add_attrs = true;
5594     }
5595
5596   return NULL_TREE;
5597 }
5598
5599 /* Handle a "sentinel" attribute.  */
5600
5601 static tree
5602 handle_sentinel_attribute (tree *node, tree name, tree args,
5603                            int ARG_UNUSED (flags), bool *no_add_attrs)
5604 {
5605   tree params = TYPE_ARG_TYPES (*node);
5606
5607   if (!params)
5608     {
5609       warning (OPT_Wattributes,
5610                "%qE attribute requires prototypes with named arguments", name);
5611       *no_add_attrs = true;
5612     }
5613   else
5614     {
5615       while (TREE_CHAIN (params))
5616         params = TREE_CHAIN (params);
5617
5618       if (VOID_TYPE_P (TREE_VALUE (params)))
5619         {
5620           warning (OPT_Wattributes,
5621                    "%qE attribute only applies to variadic functions", name);
5622           *no_add_attrs = true;
5623         }
5624     }
5625
5626   if (args)
5627     {
5628       tree position = TREE_VALUE (args);
5629
5630       if (TREE_CODE (position) != INTEGER_CST)
5631         {
5632           warning (0, "requested position is not an integer constant");
5633           *no_add_attrs = true;
5634         }
5635       else
5636         {
5637           if (tree_int_cst_lt (position, integer_zero_node))
5638             {
5639               warning (0, "requested position is less than zero");
5640               *no_add_attrs = true;
5641             }
5642         }
5643     }
5644
5645   return NULL_TREE;
5646 }
5647 \f
5648 /* Check for valid arguments being passed to a function.  */
5649 void
5650 check_function_arguments (tree attrs, tree params, tree typelist)
5651 {
5652   /* Check for null being passed in a pointer argument that must be
5653      non-null.  We also need to do this if format checking is enabled.  */
5654
5655   if (warn_nonnull)
5656     check_function_nonnull (attrs, params);
5657
5658   /* Check for errors in format strings.  */
5659
5660   if (warn_format || warn_missing_format_attribute)
5661       check_function_format (attrs, params);
5662
5663   if (warn_format)
5664     check_function_sentinel (attrs, params, typelist);
5665 }
5666
5667 /* Generic argument checking recursion routine.  PARAM is the argument to
5668    be checked.  PARAM_NUM is the number of the argument.  CALLBACK is invoked
5669    once the argument is resolved.  CTX is context for the callback.  */
5670 void
5671 check_function_arguments_recurse (void (*callback)
5672                                   (void *, tree, unsigned HOST_WIDE_INT),
5673                                   void *ctx, tree param,
5674                                   unsigned HOST_WIDE_INT param_num)
5675 {
5676   if ((TREE_CODE (param) == NOP_EXPR || TREE_CODE (param) == CONVERT_EXPR)
5677       && (TYPE_PRECISION (TREE_TYPE (param))
5678           == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (param, 0)))))
5679     {
5680       /* Strip coercion.  */
5681       check_function_arguments_recurse (callback, ctx,
5682                                         TREE_OPERAND (param, 0), param_num);
5683       return;
5684     }
5685
5686   if (TREE_CODE (param) == CALL_EXPR)
5687     {
5688       tree type = TREE_TYPE (TREE_TYPE (TREE_OPERAND (param, 0)));
5689       tree attrs;
5690       bool found_format_arg = false;
5691
5692       /* See if this is a call to a known internationalization function
5693          that modifies a format arg.  Such a function may have multiple
5694          format_arg attributes (for example, ngettext).  */
5695
5696       for (attrs = TYPE_ATTRIBUTES (type);
5697            attrs;
5698            attrs = TREE_CHAIN (attrs))
5699         if (is_attribute_p ("format_arg", TREE_PURPOSE (attrs)))
5700           {
5701             tree inner_args;
5702             tree format_num_expr;
5703             int format_num;
5704             int i;
5705
5706             /* Extract the argument number, which was previously checked
5707                to be valid.  */
5708             format_num_expr = TREE_VALUE (TREE_VALUE (attrs));
5709
5710             gcc_assert (TREE_CODE (format_num_expr) == INTEGER_CST
5711                         && !TREE_INT_CST_HIGH (format_num_expr));
5712
5713             format_num = TREE_INT_CST_LOW (format_num_expr);
5714
5715             for (inner_args = TREE_OPERAND (param, 1), i = 1;
5716                  inner_args != 0;
5717                  inner_args = TREE_CHAIN (inner_args), i++)
5718               if (i == format_num)
5719                 {
5720                   check_function_arguments_recurse (callback, ctx,
5721                                                     TREE_VALUE (inner_args),
5722                                                     param_num);
5723                   found_format_arg = true;
5724                   break;
5725                 }
5726           }
5727
5728       /* If we found a format_arg attribute and did a recursive check,
5729          we are done with checking this argument.  Otherwise, we continue
5730          and this will be considered a non-literal.  */
5731       if (found_format_arg)
5732         return;
5733     }
5734
5735   if (TREE_CODE (param) == COND_EXPR)
5736     {
5737       /* Check both halves of the conditional expression.  */
5738       check_function_arguments_recurse (callback, ctx,
5739                                         TREE_OPERAND (param, 1), param_num);
5740       check_function_arguments_recurse (callback, ctx,
5741                                         TREE_OPERAND (param, 2), param_num);
5742       return;
5743     }
5744
5745   (*callback) (ctx, param, param_num);
5746 }
5747
5748 /* Function to help qsort sort FIELD_DECLs by name order.  */
5749
5750 int
5751 field_decl_cmp (const void *x_p, const void *y_p)
5752 {
5753   const tree *const x = (const tree *const) x_p;
5754   const tree *const y = (const tree *const) y_p;
5755
5756   if (DECL_NAME (*x) == DECL_NAME (*y))
5757     /* A nontype is "greater" than a type.  */
5758     return (TREE_CODE (*y) == TYPE_DECL) - (TREE_CODE (*x) == TYPE_DECL);
5759   if (DECL_NAME (*x) == NULL_TREE)
5760     return -1;
5761   if (DECL_NAME (*y) == NULL_TREE)
5762     return 1;
5763   if (DECL_NAME (*x) < DECL_NAME (*y))
5764     return -1;
5765   return 1;
5766 }
5767
5768 static struct {
5769   gt_pointer_operator new_value;
5770   void *cookie;
5771 } resort_data;
5772
5773 /* This routine compares two fields like field_decl_cmp but using the
5774 pointer operator in resort_data.  */
5775
5776 static int
5777 resort_field_decl_cmp (const void *x_p, const void *y_p)
5778 {
5779   const tree *const x = (const tree *const) x_p;
5780   const tree *const y = (const tree *const) y_p;
5781
5782   if (DECL_NAME (*x) == DECL_NAME (*y))
5783     /* A nontype is "greater" than a type.  */
5784     return (TREE_CODE (*y) == TYPE_DECL) - (TREE_CODE (*x) == TYPE_DECL);
5785   if (DECL_NAME (*x) == NULL_TREE)
5786     return -1;
5787   if (DECL_NAME (*y) == NULL_TREE)
5788     return 1;
5789   {
5790     tree d1 = DECL_NAME (*x);
5791     tree d2 = DECL_NAME (*y);
5792     resort_data.new_value (&d1, resort_data.cookie);
5793     resort_data.new_value (&d2, resort_data.cookie);
5794     if (d1 < d2)
5795       return -1;
5796   }
5797   return 1;
5798 }
5799
5800 /* Resort DECL_SORTED_FIELDS because pointers have been reordered.  */
5801
5802 void
5803 resort_sorted_fields (void *obj,
5804                       void * ARG_UNUSED (orig_obj),
5805                       gt_pointer_operator new_value,
5806                       void *cookie)
5807 {
5808   struct sorted_fields_type *sf = (struct sorted_fields_type *) obj;
5809   resort_data.new_value = new_value;
5810   resort_data.cookie = cookie;
5811   qsort (&sf->elts[0], sf->len, sizeof (tree),
5812          resort_field_decl_cmp);
5813 }
5814
5815 /* Subroutine of c_parse_error.
5816    Return the result of concatenating LHS and RHS. RHS is really
5817    a string literal, its first character is indicated by RHS_START and
5818    RHS_SIZE is its length (including the terminating NUL character).
5819
5820    The caller is responsible for deleting the returned pointer.  */
5821
5822 static char *
5823 catenate_strings (const char *lhs, const char *rhs_start, int rhs_size)
5824 {
5825   const int lhs_size = strlen (lhs);
5826   char *result = XNEWVEC (char, lhs_size + rhs_size);
5827   strncpy (result, lhs, lhs_size);
5828   strncpy (result + lhs_size, rhs_start, rhs_size);
5829   return result;
5830 }
5831
5832 /* Issue the error given by GMSGID, indicating that it occurred before
5833    TOKEN, which had the associated VALUE.  */
5834
5835 void
5836 c_parse_error (const char *gmsgid, enum cpp_ttype token, tree value)
5837 {
5838 #define catenate_messages(M1, M2) catenate_strings ((M1), (M2), sizeof (M2))
5839
5840   char *message = NULL;
5841
5842   if (token == CPP_EOF)
5843     message = catenate_messages (gmsgid, " at end of input");
5844   else if (token == CPP_CHAR || token == CPP_WCHAR)
5845     {
5846       unsigned int val = TREE_INT_CST_LOW (value);
5847       const char *const ell = (token == CPP_CHAR) ? "" : "L";
5848       if (val <= UCHAR_MAX && ISGRAPH (val))
5849         message = catenate_messages (gmsgid, " before %s'%c'");
5850       else
5851         message = catenate_messages (gmsgid, " before %s'\\x%x'");
5852
5853       error (message, ell, val);
5854       free (message);
5855       message = NULL;
5856     }
5857   else if (token == CPP_STRING || token == CPP_WSTRING)
5858     message = catenate_messages (gmsgid, " before string constant");
5859   else if (token == CPP_NUMBER)
5860     message = catenate_messages (gmsgid, " before numeric constant");
5861   else if (token == CPP_NAME)
5862     {
5863       message = catenate_messages (gmsgid, " before %qE");
5864       error (message, value);
5865       free (message);
5866       message = NULL;
5867     }
5868   else if (token == CPP_PRAGMA)
5869     message = catenate_messages (gmsgid, " before %<#pragma%>");
5870   else if (token == CPP_PRAGMA_EOL)
5871     message = catenate_messages (gmsgid, " before end of line");
5872   else if (token < N_TTYPES)
5873     {
5874       message = catenate_messages (gmsgid, " before %qs token");
5875       error (message, cpp_type2name (token));
5876       free (message);
5877       message = NULL;
5878     }
5879   else
5880     error (gmsgid);
5881
5882   if (message)
5883     {
5884       error (message);
5885       free (message);
5886     }
5887 #undef catenate_messages
5888 }
5889
5890 /* Walk a gimplified function and warn for functions whose return value is
5891    ignored and attribute((warn_unused_result)) is set.  This is done before
5892    inlining, so we don't have to worry about that.  */
5893
5894 void
5895 c_warn_unused_result (tree *top_p)
5896 {
5897   tree t = *top_p;
5898   tree_stmt_iterator i;
5899   tree fdecl, ftype;
5900
5901   switch (TREE_CODE (t))
5902     {
5903     case STATEMENT_LIST:
5904       for (i = tsi_start (*top_p); !tsi_end_p (i); tsi_next (&i))
5905         c_warn_unused_result (tsi_stmt_ptr (i));
5906       break;
5907
5908     case COND_EXPR:
5909       c_warn_unused_result (&COND_EXPR_THEN (t));
5910       c_warn_unused_result (&COND_EXPR_ELSE (t));
5911       break;
5912     case BIND_EXPR:
5913       c_warn_unused_result (&BIND_EXPR_BODY (t));
5914       break;
5915     case TRY_FINALLY_EXPR:
5916     case TRY_CATCH_EXPR:
5917       c_warn_unused_result (&TREE_OPERAND (t, 0));
5918       c_warn_unused_result (&TREE_OPERAND (t, 1));
5919       break;
5920     case CATCH_EXPR:
5921       c_warn_unused_result (&CATCH_BODY (t));
5922       break;
5923     case EH_FILTER_EXPR:
5924       c_warn_unused_result (&EH_FILTER_FAILURE (t));
5925       break;
5926
5927     case CALL_EXPR:
5928       if (TREE_USED (t))
5929         break;
5930
5931       /* This is a naked call, as opposed to a CALL_EXPR nested inside
5932          a MODIFY_EXPR.  All calls whose value is ignored should be
5933          represented like this.  Look for the attribute.  */
5934       fdecl = get_callee_fndecl (t);
5935       if (fdecl)
5936         ftype = TREE_TYPE (fdecl);
5937       else
5938         {
5939           ftype = TREE_TYPE (TREE_OPERAND (t, 0));
5940           /* Look past pointer-to-function to the function type itself.  */
5941           ftype = TREE_TYPE (ftype);
5942         }
5943
5944       if (lookup_attribute ("warn_unused_result", TYPE_ATTRIBUTES (ftype)))
5945         {
5946           if (fdecl)
5947             warning (0, "%Hignoring return value of %qD, "
5948                      "declared with attribute warn_unused_result",
5949                      EXPR_LOCUS (t), fdecl);
5950           else
5951             warning (0, "%Hignoring return value of function "
5952                      "declared with attribute warn_unused_result",
5953                      EXPR_LOCUS (t));
5954         }
5955       break;
5956
5957     default:
5958       /* Not a container, not a call, or a call whose value is used.  */
5959       break;
5960     }
5961 }
5962
5963 /* Convert a character from the host to the target execution character
5964    set.  cpplib handles this, mostly.  */
5965
5966 HOST_WIDE_INT
5967 c_common_to_target_charset (HOST_WIDE_INT c)
5968 {
5969   /* Character constants in GCC proper are sign-extended under -fsigned-char,
5970      zero-extended under -fno-signed-char.  cpplib insists that characters
5971      and character constants are always unsigned.  Hence we must convert
5972      back and forth.  */
5973   cppchar_t uc = ((cppchar_t)c) & ((((cppchar_t)1) << CHAR_BIT)-1);
5974
5975   uc = cpp_host_to_exec_charset (parse_in, uc);
5976
5977   if (flag_signed_char)
5978     return ((HOST_WIDE_INT)uc) << (HOST_BITS_PER_WIDE_INT - CHAR_TYPE_SIZE)
5979                                >> (HOST_BITS_PER_WIDE_INT - CHAR_TYPE_SIZE);
5980   else
5981     return uc;
5982 }
5983
5984 /* Build the result of __builtin_offsetof.  EXPR is a nested sequence of
5985    component references, with STOP_REF, or alternatively an INDIRECT_REF of
5986    NULL, at the bottom; much like the traditional rendering of offsetof as a
5987    macro.  Returns the folded and properly cast result.  */
5988
5989 static tree
5990 fold_offsetof_1 (tree expr, tree stop_ref)
5991 {
5992   enum tree_code code = PLUS_EXPR;
5993   tree base, off, t;
5994
5995   if (expr == stop_ref && TREE_CODE (expr) != ERROR_MARK)
5996     return size_zero_node;
5997
5998   switch (TREE_CODE (expr))
5999     {
6000     case ERROR_MARK:
6001       return expr;
6002
6003     case VAR_DECL:
6004       error ("cannot apply %<offsetof%> to static data member %qD", expr);
6005       return error_mark_node;
6006
6007     case CALL_EXPR:
6008       error ("cannot apply %<offsetof%> when %<operator[]%> is overloaded");
6009       return error_mark_node;
6010
6011     case INTEGER_CST:
6012       gcc_assert (integer_zerop (expr));
6013       return size_zero_node;
6014
6015     case NOP_EXPR:
6016     case INDIRECT_REF:
6017       base = fold_offsetof_1 (TREE_OPERAND (expr, 0), stop_ref);
6018       gcc_assert (base == error_mark_node || base == size_zero_node);
6019       return base;
6020
6021     case COMPONENT_REF:
6022       base = fold_offsetof_1 (TREE_OPERAND (expr, 0), stop_ref);
6023       if (base == error_mark_node)
6024         return base;
6025
6026       t = TREE_OPERAND (expr, 1);
6027       if (DECL_C_BIT_FIELD (t))
6028         {
6029           error ("attempt to take address of bit-field structure "
6030                  "member %qD", t);
6031           return error_mark_node;
6032         }
6033       off = size_binop (PLUS_EXPR, DECL_FIELD_OFFSET (t),
6034                         size_int (tree_low_cst (DECL_FIELD_BIT_OFFSET (t), 1)
6035                                   / BITS_PER_UNIT));
6036       break;
6037
6038     case ARRAY_REF:
6039       base = fold_offsetof_1 (TREE_OPERAND (expr, 0), stop_ref);
6040       if (base == error_mark_node)
6041         return base;
6042
6043       t = TREE_OPERAND (expr, 1);
6044       if (TREE_CODE (t) == INTEGER_CST && tree_int_cst_sgn (t) < 0)
6045         {
6046           code = MINUS_EXPR;
6047           t = fold_build1 (NEGATE_EXPR, TREE_TYPE (t), t);
6048         }
6049       t = convert (sizetype, t);
6050       off = size_binop (MULT_EXPR, TYPE_SIZE_UNIT (TREE_TYPE (expr)), t);
6051       break;
6052
6053     default:
6054       gcc_unreachable ();
6055     }
6056
6057   return size_binop (code, base, off);
6058 }
6059
6060 tree
6061 fold_offsetof (tree expr, tree stop_ref)
6062 {
6063   /* Convert back from the internal sizetype to size_t.  */
6064   return convert (size_type_node, fold_offsetof_1 (expr, stop_ref));
6065 }
6066
6067 /* Print an error message for an invalid lvalue.  USE says
6068    how the lvalue is being used and so selects the error message.  */
6069
6070 void
6071 lvalue_error (enum lvalue_use use)
6072 {
6073   switch (use)
6074     {
6075     case lv_assign:
6076       error ("lvalue required as left operand of assignment");
6077       break;
6078     case lv_increment:
6079       error ("lvalue required as increment operand");
6080       break;
6081     case lv_decrement:
6082       error ("lvalue required as decrement operand");
6083       break;
6084     case lv_addressof:
6085       error ("lvalue required as unary %<&%> operand");
6086       break;
6087     case lv_asm:
6088       error ("lvalue required in asm statement");
6089       break;
6090     default:
6091       gcc_unreachable ();
6092     }
6093 }
6094 \f
6095 /* *PTYPE is an incomplete array.  Complete it with a domain based on
6096    INITIAL_VALUE.  If INITIAL_VALUE is not present, use 1 if DO_DEFAULT
6097    is true.  Return 0 if successful, 1 if INITIAL_VALUE can't be deciphered,
6098    2 if INITIAL_VALUE was NULL, and 3 if INITIAL_VALUE was empty.  */
6099
6100 int
6101 complete_array_type (tree *ptype, tree initial_value, bool do_default)
6102 {
6103   tree maxindex, type, main_type, elt, unqual_elt;
6104   int failure = 0, quals;
6105
6106   maxindex = size_zero_node;
6107   if (initial_value)
6108     {
6109       if (TREE_CODE (initial_value) == STRING_CST)
6110         {
6111           int eltsize
6112             = int_size_in_bytes (TREE_TYPE (TREE_TYPE (initial_value)));
6113           maxindex = size_int (TREE_STRING_LENGTH (initial_value)/eltsize - 1);
6114         }
6115       else if (TREE_CODE (initial_value) == CONSTRUCTOR)
6116         {
6117           VEC(constructor_elt,gc) *v = CONSTRUCTOR_ELTS (initial_value);
6118
6119           if (VEC_empty (constructor_elt, v))
6120             {
6121               if (pedantic)
6122                 failure = 3;
6123               maxindex = integer_minus_one_node;
6124             }
6125           else
6126             {
6127               tree curindex;
6128               unsigned HOST_WIDE_INT cnt;
6129               constructor_elt *ce;
6130
6131               if (VEC_index (constructor_elt, v, 0)->index)
6132                 maxindex = fold_convert (sizetype,
6133                                          VEC_index (constructor_elt,
6134                                                     v, 0)->index);
6135               curindex = maxindex;
6136
6137               for (cnt = 1;
6138                    VEC_iterate (constructor_elt, v, cnt, ce);
6139                    cnt++)
6140                 {
6141                   if (ce->index)
6142                     curindex = fold_convert (sizetype, ce->index);
6143                   else
6144                     curindex = size_binop (PLUS_EXPR, curindex, size_one_node);
6145
6146                   if (tree_int_cst_lt (maxindex, curindex))
6147                     maxindex = curindex;
6148                 }
6149             }
6150         }
6151       else
6152         {
6153           /* Make an error message unless that happened already.  */
6154           if (initial_value != error_mark_node)
6155             failure = 1;
6156         }
6157     }
6158   else
6159     {
6160       failure = 2;
6161       if (!do_default)
6162         return failure;
6163     }
6164
6165   type = *ptype;
6166   elt = TREE_TYPE (type);
6167   quals = TYPE_QUALS (strip_array_types (elt));
6168   if (quals == 0)
6169     unqual_elt = elt;
6170   else
6171     unqual_elt = c_build_qualified_type (elt, TYPE_UNQUALIFIED);
6172
6173   /* Using build_distinct_type_copy and modifying things afterward instead
6174      of using build_array_type to create a new type preserves all of the
6175      TYPE_LANG_FLAG_? bits that the front end may have set.  */
6176   main_type = build_distinct_type_copy (TYPE_MAIN_VARIANT (type));
6177   TREE_TYPE (main_type) = unqual_elt;
6178   TYPE_DOMAIN (main_type) = build_index_type (maxindex);
6179   layout_type (main_type);
6180
6181   if (quals == 0)
6182     type = main_type;
6183   else
6184     type = c_build_qualified_type (main_type, quals);
6185
6186   *ptype = type;
6187   return failure;
6188 }
6189
6190 \f
6191 /* Used to help initialize the builtin-types.def table.  When a type of
6192    the correct size doesn't exist, use error_mark_node instead of NULL.
6193    The later results in segfaults even when a decl using the type doesn't
6194    get invoked.  */
6195
6196 tree
6197 builtin_type_for_size (int size, bool unsignedp)
6198 {
6199   tree type = lang_hooks.types.type_for_size (size, unsignedp);
6200   return type ? type : error_mark_node;
6201 }
6202
6203 /* A helper function for resolve_overloaded_builtin in resolving the
6204    overloaded __sync_ builtins.  Returns a positive power of 2 if the
6205    first operand of PARAMS is a pointer to a supported data type.
6206    Returns 0 if an error is encountered.  */
6207
6208 static int
6209 sync_resolve_size (tree function, tree params)
6210 {
6211   tree type;
6212   int size;
6213
6214   if (params == NULL)
6215     {
6216       error ("too few arguments to function %qE", function);
6217       return 0;
6218     }
6219
6220   type = TREE_TYPE (TREE_VALUE (params));
6221   if (TREE_CODE (type) != POINTER_TYPE)
6222     goto incompatible;
6223
6224   type = TREE_TYPE (type);
6225   if (!INTEGRAL_TYPE_P (type) && !POINTER_TYPE_P (type))
6226     goto incompatible;
6227
6228   size = tree_low_cst (TYPE_SIZE_UNIT (type), 1);
6229   if (size == 1 || size == 2 || size == 4 || size == 8 || size == 16)
6230     return size;
6231
6232  incompatible:
6233   error ("incompatible type for argument %d of %qE", 1, function);
6234   return 0;
6235 }
6236
6237 /* A helper function for resolve_overloaded_builtin.  Adds casts to
6238    PARAMS to make arguments match up with those of FUNCTION.  Drops
6239    the variadic arguments at the end.  Returns false if some error
6240    was encountered; true on success.  */
6241
6242 static bool
6243 sync_resolve_params (tree orig_function, tree function, tree params)
6244 {
6245   tree arg_types = TYPE_ARG_TYPES (TREE_TYPE (function));
6246   tree ptype;
6247   int number;
6248
6249   /* We've declared the implementation functions to use "volatile void *"
6250      as the pointer parameter, so we shouldn't get any complaints from the
6251      call to check_function_arguments what ever type the user used.  */
6252   arg_types = TREE_CHAIN (arg_types);
6253   ptype = TREE_TYPE (TREE_TYPE (TREE_VALUE (params)));
6254   number = 2;
6255
6256   /* For the rest of the values, we need to cast these to FTYPE, so that we
6257      don't get warnings for passing pointer types, etc.  */
6258   while (arg_types != void_list_node)
6259     {
6260       tree val;
6261
6262       params = TREE_CHAIN (params);
6263       if (params == NULL)
6264         {
6265           error ("too few arguments to function %qE", orig_function);
6266           return false;
6267         }
6268
6269       /* ??? Ideally for the first conversion we'd use convert_for_assignment
6270          so that we get warnings for anything that doesn't match the pointer
6271          type.  This isn't portable across the C and C++ front ends atm.  */
6272       val = TREE_VALUE (params);
6273       val = convert (ptype, val);
6274       val = convert (TREE_VALUE (arg_types), val);
6275       TREE_VALUE (params) = val;
6276
6277       arg_types = TREE_CHAIN (arg_types);
6278       number++;
6279     }
6280
6281   /* The definition of these primitives is variadic, with the remaining
6282      being "an optional list of variables protected by the memory barrier".
6283      No clue what that's supposed to mean, precisely, but we consider all
6284      call-clobbered variables to be protected so we're safe.  */
6285   TREE_CHAIN (params) = NULL;
6286
6287   return true;
6288 }
6289
6290 /* A helper function for resolve_overloaded_builtin.  Adds a cast to
6291    RESULT to make it match the type of the first pointer argument in
6292    PARAMS.  */
6293
6294 static tree
6295 sync_resolve_return (tree params, tree result)
6296 {
6297   tree ptype = TREE_TYPE (TREE_TYPE (TREE_VALUE (params)));
6298   ptype = TYPE_MAIN_VARIANT (ptype);
6299   return convert (ptype, result);
6300 }
6301
6302 /* Some builtin functions are placeholders for other expressions.  This
6303    function should be called immediately after parsing the call expression
6304    before surrounding code has committed to the type of the expression.
6305
6306    FUNCTION is the DECL that has been invoked; it is known to be a builtin.
6307    PARAMS is the argument list for the call.  The return value is non-null
6308    when expansion is complete, and null if normal processing should
6309    continue.  */
6310
6311 tree
6312 resolve_overloaded_builtin (tree function, tree params)
6313 {
6314   enum built_in_function orig_code = DECL_FUNCTION_CODE (function);
6315   switch (DECL_BUILT_IN_CLASS (function))
6316     {
6317     case BUILT_IN_NORMAL:
6318       break;
6319     case BUILT_IN_MD:
6320       if (targetm.resolve_overloaded_builtin)
6321         return targetm.resolve_overloaded_builtin (function, params);
6322       else
6323         return NULL_TREE;
6324     default:
6325       return NULL_TREE;
6326     }
6327
6328   /* Handle BUILT_IN_NORMAL here.  */
6329   switch (orig_code)
6330     {
6331     case BUILT_IN_FETCH_AND_ADD_N:
6332     case BUILT_IN_FETCH_AND_SUB_N:
6333     case BUILT_IN_FETCH_AND_OR_N:
6334     case BUILT_IN_FETCH_AND_AND_N:
6335     case BUILT_IN_FETCH_AND_XOR_N:
6336     case BUILT_IN_FETCH_AND_NAND_N:
6337     case BUILT_IN_ADD_AND_FETCH_N:
6338     case BUILT_IN_SUB_AND_FETCH_N:
6339     case BUILT_IN_OR_AND_FETCH_N:
6340     case BUILT_IN_AND_AND_FETCH_N:
6341     case BUILT_IN_XOR_AND_FETCH_N:
6342     case BUILT_IN_NAND_AND_FETCH_N:
6343     case BUILT_IN_BOOL_COMPARE_AND_SWAP_N:
6344     case BUILT_IN_VAL_COMPARE_AND_SWAP_N:
6345     case BUILT_IN_LOCK_TEST_AND_SET_N:
6346     case BUILT_IN_LOCK_RELEASE_N:
6347       {
6348         int n = sync_resolve_size (function, params);
6349         tree new_function, result;
6350
6351         if (n == 0)
6352           return error_mark_node;
6353
6354         new_function = built_in_decls[orig_code + exact_log2 (n) + 1];
6355         if (!sync_resolve_params (function, new_function, params))
6356           return error_mark_node;
6357
6358         result = build_function_call (new_function, params);
6359         if (orig_code != BUILT_IN_BOOL_COMPARE_AND_SWAP_N
6360             && orig_code != BUILT_IN_LOCK_RELEASE_N)
6361           result = sync_resolve_return (params, result);
6362
6363         return result;
6364       }
6365
6366     default:
6367       return NULL_TREE;
6368     }
6369 }
6370
6371 /* Ignoring their sign, return true if two scalar types are the same.  */
6372 bool
6373 same_scalar_type_ignoring_signedness (tree t1, tree t2)
6374 {
6375   enum tree_code c1 = TREE_CODE (t1), c2 = TREE_CODE (t2);
6376
6377   gcc_assert ((c1 == INTEGER_TYPE || c1 == REAL_TYPE)
6378               && (c2 == INTEGER_TYPE || c2 == REAL_TYPE));
6379
6380   /* Equality works here because c_common_signed_type uses
6381      TYPE_MAIN_VARIANT.  */
6382   return lang_hooks.types.signed_type (t1)
6383     == lang_hooks.types.signed_type (t2);
6384 }
6385
6386 /* Check for missing format attributes on function pointers.  LTYPE is
6387    the new type or left-hand side type.  RTYPE is the old type or
6388    right-hand side type.  Returns TRUE if LTYPE is missing the desired
6389    attribute.  */
6390
6391 bool
6392 check_missing_format_attribute (tree ltype, tree rtype)
6393 {
6394   tree const ttr = TREE_TYPE (rtype), ttl = TREE_TYPE (ltype);
6395   tree ra;
6396
6397   for (ra = TYPE_ATTRIBUTES (ttr); ra; ra = TREE_CHAIN (ra))
6398     if (is_attribute_p ("format", TREE_PURPOSE (ra)))
6399       break;
6400   if (ra)
6401     {
6402       tree la;
6403       for (la = TYPE_ATTRIBUTES (ttl); la; la = TREE_CHAIN (la))
6404         if (is_attribute_p ("format", TREE_PURPOSE (la)))
6405           break;
6406       return !la;
6407     }
6408   else
6409     return false;
6410 }
6411
6412 /* Subscripting with type char is likely to lose on a machine where
6413    chars are signed.  So warn on any machine, but optionally.  Don't
6414    warn for unsigned char since that type is safe.  Don't warn for
6415    signed char because anyone who uses that must have done so
6416    deliberately. Furthermore, we reduce the false positive load by
6417    warning only for non-constant value of type char.  */
6418
6419 void
6420 warn_array_subscript_with_type_char (tree index)
6421 {
6422   if (TYPE_MAIN_VARIANT (TREE_TYPE (index)) == char_type_node
6423       && TREE_CODE (index) != INTEGER_CST)
6424     warning (OPT_Wchar_subscripts, "array subscript has type %<char%>");
6425 }
6426
6427
6428 #include "gt-c-common.h"