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, 2006, 2007, 2008 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 3, 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 COPYING3.  If not see
  19 <http://www.gnu.org/licenses/>.  */
  20
  21 #include "config.h"
  22 #include "system.h"
  23 #include "coretypes.h"
  24 #include "tm.h"
  25 #include "intl.h"
  26 #include "tree.h"
  27 #include "flags.h"
  28 #include "output.h"
  29 #include "c-pragma.h"
  30 #include "rtl.h"
  31 #include "ggc.h"
  32 #include "varray.h"
  33 #include "expr.h"
  34 #include "c-common.h"
  35 #include "diagnostic.h"
  36 #include "tm_p.h"
  37 #include "obstack.h"
  38 #include "cpplib.h"
  39 #include "target.h"
  40 #include "langhooks.h"
  41 #include "tree-inline.h"
  42 #include "c-tree.h"
  43 #include "toplev.h"
  44 #include "tree-iterator.h"
  45 #include "hashtab.h"
  46 #include "tree-mudflap.h"
  47 #include "opts.h"
  48 #include "real.h"
  49 #include "cgraph.h"
  50 #include "target-def.h"
  51 #include "fixed-value.h"
  52
  53 cpp_reader *parse_in;           /* Declared in c-pragma.h.  */
  54
  55 /* We let tm.h override the types used here, to handle trivial differences
  56    such as the choice of unsigned int or long unsigned int for size_t.
  57    When machines start needing nontrivial differences in the size type,
  58    it would be best to do something here to figure out automatically
  59    from other information what type to use.  */
  60
  61 #ifndef SIZE_TYPE
  62 #define SIZE_TYPE "long unsigned int"
  63 #endif
  64
  65 #ifndef PID_TYPE
  66 #define PID_TYPE "int"
  67 #endif
  68
  69 #ifndef WCHAR_TYPE
  70 #define WCHAR_TYPE "int"
  71 #endif
  72
  73 /* WCHAR_TYPE gets overridden by -fshort-wchar.  */
  74 #define MODIFIED_WCHAR_TYPE \
  75         (flag_short_wchar ? "short unsigned int" : WCHAR_TYPE)
  76
  77 #ifndef PTRDIFF_TYPE
  78 #define PTRDIFF_TYPE "long int"
  79 #endif
  80
  81 #ifndef WINT_TYPE
  82 #define WINT_TYPE "unsigned int"
  83 #endif
  84
  85 #ifndef INTMAX_TYPE
  86 #define INTMAX_TYPE ((INT_TYPE_SIZE == LONG_LONG_TYPE_SIZE)     \
  87                      ? "int"                                    \
  88                      : ((LONG_TYPE_SIZE == LONG_LONG_TYPE_SIZE) \
  89                         ? "long int"                            \
  90                         : "long long int"))
  91 #endif
  92
  93 #ifndef UINTMAX_TYPE
  94 #define UINTMAX_TYPE ((INT_TYPE_SIZE == LONG_LONG_TYPE_SIZE)    \
  95                      ? "unsigned int"                           \
  96                      : ((LONG_TYPE_SIZE == LONG_LONG_TYPE_SIZE) \
  97                         ? "long unsigned int"                   \
  98                         : "long long unsigned int"))
  99 #endif
 100
 101 /* The following symbols are subsumed in the c_global_trees array, and
 102    listed here individually for documentation purposes.
 103
 104    INTEGER_TYPE and REAL_TYPE nodes for the standard data types.
 105
 106         tree short_integer_type_node;
 107         tree long_integer_type_node;
 108         tree long_long_integer_type_node;
 109
 110         tree short_unsigned_type_node;
 111         tree long_unsigned_type_node;
 112         tree long_long_unsigned_type_node;
 113
 114         tree truthvalue_type_node;
 115         tree truthvalue_false_node;
 116         tree truthvalue_true_node;
 117
 118         tree ptrdiff_type_node;
 119
 120         tree unsigned_char_type_node;
 121         tree signed_char_type_node;
 122         tree wchar_type_node;
 123         tree signed_wchar_type_node;
 124         tree unsigned_wchar_type_node;
 125
 126         tree float_type_node;
 127         tree double_type_node;
 128         tree long_double_type_node;
 129
 130         tree complex_integer_type_node;
 131         tree complex_float_type_node;
 132         tree complex_double_type_node;
 133         tree complex_long_double_type_node;
 134
 135         tree dfloat32_type_node;
 136         tree dfloat64_type_node;
 137         tree_dfloat128_type_node;
 138
 139         tree intQI_type_node;
 140         tree intHI_type_node;
 141         tree intSI_type_node;
 142         tree intDI_type_node;
 143         tree intTI_type_node;
 144
 145         tree unsigned_intQI_type_node;
 146         tree unsigned_intHI_type_node;
 147         tree unsigned_intSI_type_node;
 148         tree unsigned_intDI_type_node;
 149         tree unsigned_intTI_type_node;
 150
 151         tree widest_integer_literal_type_node;
 152         tree widest_unsigned_literal_type_node;
 153
 154    Nodes for types `void *' and `const void *'.
 155
 156         tree ptr_type_node, const_ptr_type_node;
 157
 158    Nodes for types `char *' and `const char *'.
 159
 160         tree string_type_node, const_string_type_node;
 161
 162    Type `char[SOMENUMBER]'.
 163    Used when an array of char is needed and the size is irrelevant.
 164
 165         tree char_array_type_node;
 166
 167    Type `int[SOMENUMBER]' or something like it.
 168    Used when an array of int needed and the size is irrelevant.
 169
 170         tree int_array_type_node;
 171
 172    Type `wchar_t[SOMENUMBER]' or something like it.
 173    Used when a wide string literal is created.
 174
 175         tree wchar_array_type_node;
 176
 177    Type `int ()' -- used for implicit declaration of functions.
 178
 179         tree default_function_type;
 180
 181    A VOID_TYPE node, packaged in a TREE_LIST.
 182
 183         tree void_list_node;
 184
 185   The lazily created VAR_DECLs for __FUNCTION__, __PRETTY_FUNCTION__,
 186   and __func__. (C doesn't generate __FUNCTION__ and__PRETTY_FUNCTION__
 187   VAR_DECLS, but C++ does.)
 188
 189         tree function_name_decl_node;
 190         tree pretty_function_name_decl_node;
 191         tree c99_function_name_decl_node;
 192
 193   Stack of nested function name VAR_DECLs.
 194
 195         tree saved_function_name_decls;
 196
 197 */
 198
 199 tree c_global_trees[CTI_MAX];
 200 \f
 201 /* Switches common to the C front ends.  */
 202
 203 /* Nonzero if prepreprocessing only.  */
 204
 205 int flag_preprocess_only;
 206
 207 /* Nonzero means don't output line number information.  */
 208
 209 char flag_no_line_commands;
 210
 211 /* Nonzero causes -E output not to be done, but directives such as
 212    #define that have side effects are still obeyed.  */
 213
 214 char flag_no_output;
 215
 216 /* Nonzero means dump macros in some fashion.  */
 217
 218 char flag_dump_macros;
 219
 220 /* Nonzero means pass #include lines through to the output.  */
 221
 222 char flag_dump_includes;
 223
 224 /* Nonzero means process PCH files while preprocessing.  */
 225
 226 bool flag_pch_preprocess;
 227
 228 /* The file name to which we should write a precompiled header, or
 229    NULL if no header will be written in this compile.  */
 230
 231 const char *pch_file;
 232
 233 /* Nonzero if an ISO standard was selected.  It rejects macros in the
 234    user's namespace.  */
 235 int flag_iso;
 236
 237 /* Nonzero if -undef was given.  It suppresses target built-in macros
 238    and assertions.  */
 239 int flag_undef;
 240
 241 /* Nonzero means don't recognize the non-ANSI builtin functions.  */
 242
 243 int flag_no_builtin;
 244
 245 /* Nonzero means don't recognize the non-ANSI builtin functions.
 246    -ansi sets this.  */
 247
 248 int flag_no_nonansi_builtin;
 249
 250 /* Nonzero means give `double' the same size as `float'.  */
 251
 252 int flag_short_double;
 253
 254 /* Nonzero means give `wchar_t' the same size as `short'.  */
 255
 256 int flag_short_wchar;
 257
 258 /* Nonzero means allow implicit conversions between vectors with
 259    differing numbers of subparts and/or differing element types.  */
 260 int flag_lax_vector_conversions;
 261
 262 /* Nonzero means allow Microsoft extensions without warnings or errors.  */
 263 int flag_ms_extensions;
 264
 265 /* Nonzero means don't recognize the keyword `asm'.  */
 266
 267 int flag_no_asm;
 268
 269 /* Nonzero means to treat bitfields as signed unless they say `unsigned'.  */
 270
 271 int flag_signed_bitfields = 1;
 272
 273 /* Warn about #pragma directives that are not recognized.  */
 274
 275 int warn_unknown_pragmas; /* Tri state variable.  */
 276
 277 /* Warn about format/argument anomalies in calls to formatted I/O functions
 278    (*printf, *scanf, strftime, strfmon, etc.).  */
 279
 280 int warn_format;
 281
 282 /* Warn about using __null (as NULL in C++) as sentinel.  For code compiled
 283    with GCC this doesn't matter as __null is guaranteed to have the right
 284    size.  */
 285
 286 int warn_strict_null_sentinel;
 287
 288 /* Zero means that faster, ...NonNil variants of objc_msgSend...
 289    calls will be used in ObjC; passing nil receivers to such calls
 290    will most likely result in crashes.  */
 291 int flag_nil_receivers = 1;
 292
 293 /* Nonzero means that code generation will be altered to support
 294    "zero-link" execution.  This currently affects ObjC only, but may
 295    affect other languages in the future.  */
 296 int flag_zero_link = 0;
 297
 298 /* Nonzero means emit an '__OBJC, __image_info' for the current translation
 299    unit.  It will inform the ObjC runtime that class definition(s) herein
 300    contained are to replace one(s) previously loaded.  */
 301 int flag_replace_objc_classes = 0;
 302
 303 /* C/ObjC language option variables.  */
 304
 305
 306 /* Nonzero means allow type mismatches in conditional expressions;
 307    just make their values `void'.  */
 308
 309 int flag_cond_mismatch;
 310
 311 /* Nonzero means enable C89 Amendment 1 features.  */
 312
 313 int flag_isoc94;
 314
 315 /* Nonzero means use the ISO C99 dialect of C.  */
 316
 317 int flag_isoc99;
 318
 319 /* Nonzero means that we have builtin functions, and main is an int.  */
 320
 321 int flag_hosted = 1;
 322
 323 /* Warn if main is suspicious.  */
 324
 325 int warn_main;
 326
 327
 328 /* ObjC language option variables.  */
 329
 330
 331 /* Open and close the file for outputting class declarations, if
 332    requested (ObjC).  */
 333
 334 int flag_gen_declaration;
 335
 336 /* Tells the compiler that this is a special run.  Do not perform any
 337    compiling, instead we are to test some platform dependent features
 338    and output a C header file with appropriate definitions.  */
 339
 340 int print_struct_values;
 341
 342 /* Tells the compiler what is the constant string class for Objc.  */
 343
 344 const char *constant_string_class_name;
 345
 346
 347 /* C++ language option variables.  */
 348
 349
 350 /* Nonzero means don't recognize any extension keywords.  */
 351
 352 int flag_no_gnu_keywords;
 353
 354 /* Nonzero means do emit exported implementations of functions even if
 355    they can be inlined.  */
 356
 357 int flag_implement_inlines = 1;
 358
 359 /* Nonzero means that implicit instantiations will be emitted if needed.  */
 360
 361 int flag_implicit_templates = 1;
 362
 363 /* Nonzero means that implicit instantiations of inline templates will be
 364    emitted if needed, even if instantiations of non-inline templates
 365    aren't.  */
 366
 367 int flag_implicit_inline_templates = 1;
 368
 369 /* Nonzero means generate separate instantiation control files and
 370    juggle them at link time.  */
 371
 372 int flag_use_repository;
 373
 374 /* Nonzero if we want to issue diagnostics that the standard says are not
 375    required.  */
 376
 377 int flag_optional_diags = 1;
 378
 379 /* Nonzero means we should attempt to elide constructors when possible.  */
 380
 381 int flag_elide_constructors = 1;
 382
 383 /* Nonzero means that member functions defined in class scope are
 384    inline by default.  */
 385
 386 int flag_default_inline = 1;
 387
 388 /* Controls whether compiler generates 'type descriptor' that give
 389    run-time type information.  */
 390
 391 int flag_rtti = 1;
 392
 393 /* Nonzero if we want to conserve space in the .o files.  We do this
 394    by putting uninitialized data and runtime initialized data into
 395    .common instead of .data at the expense of not flagging multiple
 396    definitions.  */
 397
 398 int flag_conserve_space;
 399
 400 /* Nonzero if we want to obey access control semantics.  */
 401
 402 int flag_access_control = 1;
 403
 404 /* Nonzero if we want to check the return value of new and avoid calling
 405    constructors if it is a null pointer.  */
 406
 407 int flag_check_new;
 408
 409 /* The C++ dialect being used. C++98 is the default.  */
 410
 411 enum cxx_dialect cxx_dialect = cxx98;
 412
 413 /* Nonzero if we want the new ISO rules for pushing a new scope for `for'
 414    initialization variables.
 415    0: Old rules, set by -fno-for-scope.
 416    2: New ISO rules, set by -ffor-scope.
 417    1: Try to implement new ISO rules, but with backup compatibility
 418    (and warnings).  This is the default, for now.  */
 419
 420 int flag_new_for_scope = 1;
 421
 422 /* Nonzero if we want to emit defined symbols with common-like linkage as
 423    weak symbols where possible, in order to conform to C++ semantics.
 424    Otherwise, emit them as local symbols.  */
 425
 426 int flag_weak = 1;
 427
 428 /* 0 means we want the preprocessor to not emit line directives for
 429    the current working directory.  1 means we want it to do it.  -1
 430    means we should decide depending on whether debugging information
 431    is being emitted or not.  */
 432
 433 int flag_working_directory = -1;
 434
 435 /* Nonzero to use __cxa_atexit, rather than atexit, to register
 436    destructors for local statics and global objects.  '2' means it has been
 437    set nonzero as a default, not by a command-line flag.  */
 438
 439 int flag_use_cxa_atexit = DEFAULT_USE_CXA_ATEXIT;
 440
 441 /* Nonzero to use __cxa_get_exception_ptr in C++ exception-handling
 442    code.  '2' means it has not been set explicitly on the command line.  */
 443
 444 int flag_use_cxa_get_exception_ptr = 2;
 445
 446 /* Nonzero means make the default pedwarns warnings instead of errors.
 447    The value of this flag is ignored if -pedantic is specified.  */
 448
 449 int flag_permissive;
 450
 451 /* Nonzero means to implement standard semantics for exception
 452    specifications, calling unexpected if an exception is thrown that
 453    doesn't match the specification.  Zero means to treat them as
 454    assertions and optimize accordingly, but not check them.  */
 455
 456 int flag_enforce_eh_specs = 1;
 457
 458 /* Nonzero means to generate thread-safe code for initializing local
 459    statics.  */
 460
 461 int flag_threadsafe_statics = 1;
 462
 463 /* Nonzero means warn about implicit declarations.  */
 464
 465 int warn_implicit = 1;
 466
 467 /* Maximum template instantiation depth.  This limit is rather
 468    arbitrary, but it exists to limit the time it takes to notice
 469    infinite template instantiations.  */
 470
 471 int max_tinst_depth = 500;
 472
 473
 474
 475 /* The elements of `ridpointers' are identifier nodes for the reserved
 476    type names and storage classes.  It is indexed by a RID_... value.  */
 477 tree *ridpointers;
 478
 479 tree (*make_fname_decl) (tree, int);
 480
 481 /* Nonzero means the expression being parsed will never be evaluated.
 482    This is a count, since unevaluated expressions can nest.  */
 483 int skip_evaluation;
 484
 485 /* Information about how a function name is generated.  */
 486 struct fname_var_t
 487 {
 488   tree *const decl;     /* pointer to the VAR_DECL.  */
 489   const unsigned rid;   /* RID number for the identifier.  */
 490   const int pretty;     /* How pretty is it? */
 491 };
 492
 493 /* The three ways of getting then name of the current function.  */
 494
 495 const struct fname_var_t fname_vars[] =
 496 {
 497   /* C99 compliant __func__, must be first.  */
 498   {&c99_function_name_decl_node, RID_C99_FUNCTION_NAME, 0},
 499   /* GCC __FUNCTION__ compliant.  */
 500   {&function_name_decl_node, RID_FUNCTION_NAME, 0},
 501   /* GCC __PRETTY_FUNCTION__ compliant.  */
 502   {&pretty_function_name_decl_node, RID_PRETTY_FUNCTION_NAME, 1},
 503   {NULL, 0, 0},
 504 };
 505
 506 static tree check_case_value (tree);
 507 static bool check_case_bounds (tree, tree, tree *, tree *);
 508
 509 static tree handle_packed_attribute (tree *, tree, tree, int, bool *);
 510 static tree handle_nocommon_attribute (tree *, tree, tree, int, bool *);
 511 static tree handle_common_attribute (tree *, tree, tree, int, bool *);
 512 static tree handle_noreturn_attribute (tree *, tree, tree, int, bool *);
 513 static tree handle_hot_attribute (tree *, tree, tree, int, bool *);
 514 static tree handle_cold_attribute (tree *, tree, tree, int, bool *);
 515 static tree handle_noinline_attribute (tree *, tree, tree, int, bool *);
 516 static tree handle_always_inline_attribute (tree *, tree, tree, int,
 517                                             bool *);
 518 static tree handle_gnu_inline_attribute (tree *, tree, tree, int, bool *);
 519 static tree handle_artificial_attribute (tree *, tree, tree, int, bool *);
 520 static tree handle_flatten_attribute (tree *, tree, tree, int, bool *);
 521 static tree handle_error_attribute (tree *, tree, tree, int, bool *);
 522 static tree handle_used_attribute (tree *, tree, tree, int, bool *);
 523 static tree handle_unused_attribute (tree *, tree, tree, int, bool *);
 524 static tree handle_externally_visible_attribute (tree *, tree, tree, int,
 525                                                  bool *);
 526 static tree handle_const_attribute (tree *, tree, tree, int, bool *);
 527 static tree handle_transparent_union_attribute (tree *, tree, tree,
 528                                                 int, bool *);
 529 static tree handle_constructor_attribute (tree *, tree, tree, int, bool *);
 530 static tree handle_destructor_attribute (tree *, tree, tree, int, bool *);
 531 static tree handle_mode_attribute (tree *, tree, tree, int, bool *);
 532 static tree handle_section_attribute (tree *, tree, tree, int, bool *);
 533 static tree handle_aligned_attribute (tree *, tree, tree, int, bool *);
 534 static tree handle_weak_attribute (tree *, tree, tree, int, bool *) ;
 535 static tree handle_alias_attribute (tree *, tree, tree, int, bool *);
 536 static tree handle_weakref_attribute (tree *, tree, tree, int, bool *) ;
 537 static tree handle_visibility_attribute (tree *, tree, tree, int,
 538                                          bool *);
 539 static tree handle_tls_model_attribute (tree *, tree, tree, int,
 540                                         bool *);
 541 static tree handle_no_instrument_function_attribute (tree *, tree,
 542                                                      tree, int, bool *);
 543 static tree handle_malloc_attribute (tree *, tree, tree, int, bool *);
 544 static tree handle_returns_twice_attribute (tree *, tree, tree, int, bool *);
 545 static tree handle_no_limit_stack_attribute (tree *, tree, tree, int,
 546                                              bool *);
 547 static tree handle_pure_attribute (tree *, tree, tree, int, bool *);
 548 static tree handle_novops_attribute (tree *, tree, tree, int, bool *);
 549 static tree handle_deprecated_attribute (tree *, tree, tree, int,
 550                                          bool *);
 551 static tree handle_vector_size_attribute (tree *, tree, tree, int,
 552                                           bool *);
 553 static tree handle_nonnull_attribute (tree *, tree, tree, int, bool *);
 554 static tree handle_nothrow_attribute (tree *, tree, tree, int, bool *);
 555 static tree handle_cleanup_attribute (tree *, tree, tree, int, bool *);
 556 static tree handle_warn_unused_result_attribute (tree *, tree, tree, int,
 557                                                  bool *);
 558 static tree handle_sentinel_attribute (tree *, tree, tree, int, bool *);
 559 static tree handle_type_generic_attribute (tree *, tree, tree, int, bool *);
 560 static tree handle_alloc_size_attribute (tree *, tree, tree, int, bool *);
 561
 562 static void check_function_nonnull (tree, int, tree *);
 563 static void check_nonnull_arg (void *, tree, unsigned HOST_WIDE_INT);
 564 static bool nonnull_check_p (tree, unsigned HOST_WIDE_INT);
 565 static bool get_nonnull_operand (tree, unsigned HOST_WIDE_INT *);
 566 static int resort_field_decl_cmp (const void *, const void *);
 567
 568 /* Table of machine-independent attributes common to all C-like languages.  */
 569 const struct attribute_spec c_common_attribute_table[] =
 570 {
 571   /* { name, min_len, max_len, decl_req, type_req, fn_type_req, handler } */
 572   { "packed",                 0, 0, false, false, false,
 573                               handle_packed_attribute },
 574   { "nocommon",               0, 0, true,  false, false,
 575                               handle_nocommon_attribute },
 576   { "common",                 0, 0, true,  false, false,
 577                               handle_common_attribute },
 578   /* FIXME: logically, noreturn attributes should be listed as
 579      "false, true, true" and apply to function types.  But implementing this
 580      would require all the places in the compiler that use TREE_THIS_VOLATILE
 581      on a decl to identify non-returning functions to be located and fixed
 582      to check the function type instead.  */
 583   { "noreturn",               0, 0, true,  false, false,
 584                               handle_noreturn_attribute },
 585   { "volatile",               0, 0, true,  false, false,
 586                               handle_noreturn_attribute },
 587   { "noinline",               0, 0, true,  false, false,
 588                               handle_noinline_attribute },
 589   { "always_inline",          0, 0, true,  false, false,
 590                               handle_always_inline_attribute },
 591   { "gnu_inline",             0, 0, true,  false, false,
 592                               handle_gnu_inline_attribute },
 593   { "artificial",             0, 0, true,  false, false,
 594                               handle_artificial_attribute },
 595   { "flatten",                0, 0, true,  false, false,
 596                               handle_flatten_attribute },
 597   { "used",                   0, 0, true,  false, false,
 598                               handle_used_attribute },
 599   { "unused",                 0, 0, false, false, false,
 600                               handle_unused_attribute },
 601   { "externally_visible",     0, 0, true,  false, false,
 602                               handle_externally_visible_attribute },
 603   /* The same comments as for noreturn attributes apply to const ones.  */
 604   { "const",                  0, 0, true,  false, false,
 605                               handle_const_attribute },
 606   { "transparent_union",      0, 0, false, false, false,
 607                               handle_transparent_union_attribute },
 608   { "constructor",            0, 1, true,  false, false,
 609                               handle_constructor_attribute },
 610   { "destructor",             0, 1, true,  false, false,
 611                               handle_destructor_attribute },
 612   { "mode",                   1, 1, false,  true, false,
 613                               handle_mode_attribute },
 614   { "section",                1, 1, true,  false, false,
 615                               handle_section_attribute },
 616   { "aligned",                0, 1, false, false, false,
 617                               handle_aligned_attribute },
 618   { "weak",                   0, 0, true,  false, false,
 619                               handle_weak_attribute },
 620   { "alias",                  1, 1, true,  false, false,
 621                               handle_alias_attribute },
 622   { "weakref",                0, 1, true,  false, false,
 623                               handle_weakref_attribute },
 624   { "no_instrument_function", 0, 0, true,  false, false,
 625                               handle_no_instrument_function_attribute },
 626   { "malloc",                 0, 0, true,  false, false,
 627                               handle_malloc_attribute },
 628   { "returns_twice",          0, 0, true,  false, false,
 629                               handle_returns_twice_attribute },
 630   { "no_stack_limit",         0, 0, true,  false, false,
 631                               handle_no_limit_stack_attribute },
 632   { "pure",                   0, 0, true,  false, false,
 633                               handle_pure_attribute },
 634   /* For internal use (marking of builtins) only.  The name contains space
 635      to prevent its usage in source code.  */
 636   { "no vops",                0, 0, true,  false, false,
 637                               handle_novops_attribute },
 638   { "deprecated",             0, 0, false, false, false,
 639                               handle_deprecated_attribute },
 640   { "vector_size",            1, 1, false, true, false,
 641                               handle_vector_size_attribute },
 642   { "visibility",             1, 1, false, false, false,
 643                               handle_visibility_attribute },
 644   { "tls_model",              1, 1, true,  false, false,
 645                               handle_tls_model_attribute },
 646   { "nonnull",                0, -1, false, true, true,
 647                               handle_nonnull_attribute },
 648   { "nothrow",                0, 0, true,  false, false,
 649                               handle_nothrow_attribute },
 650   { "may_alias",              0, 0, false, true, false, NULL },
 651   { "cleanup",                1, 1, true, false, false,
 652                               handle_cleanup_attribute },
 653   { "warn_unused_result",     0, 0, false, true, true,
 654                               handle_warn_unused_result_attribute },
 655   { "sentinel",               0, 1, false, true, true,
 656                               handle_sentinel_attribute },
 657   /* For internal use (marking of builtins) only.  The name contains space
 658      to prevent its usage in source code.  */
 659   { "type generic",           0, 0, false, true, true,
 660                               handle_type_generic_attribute },
 661   { "alloc_size",             1, 2, false, true, true,
 662                               handle_alloc_size_attribute },
 663   { "cold",                   0, 0, true,  false, false,
 664                               handle_cold_attribute },
 665   { "hot",                    0, 0, true,  false, false,
 666                               handle_hot_attribute },
 667   { "warning",                1, 1, true,  false, false,
 668                               handle_error_attribute },
 669   { "error",                  1, 1, true,  false, false,
 670                               handle_error_attribute },
 671   { NULL,                     0, 0, false, false, false, NULL }
 672 };
 673
 674 /* Give the specifications for the format attributes, used by C and all
 675    descendants.  */
 676
 677 const struct attribute_spec c_common_format_attribute_table[] =
 678 {
 679   /* { name, min_len, max_len, decl_req, type_req, fn_type_req, handler } */
 680   { "format",                 3, 3, false, true,  true,
 681                               handle_format_attribute },
 682   { "format_arg",             1, 1, false, true,  true,
 683                               handle_format_arg_attribute },
 684   { NULL,                     0, 0, false, false, false, NULL }
 685 };
 686
 687 /* Push current bindings for the function name VAR_DECLS.  */
 688
 689 void
 690 start_fname_decls (void)
 691 {
 692   unsigned ix;
 693   tree saved = NULL_TREE;
 694
 695   for (ix = 0; fname_vars[ix].decl; ix++)
 696     {
 697       tree decl = *fname_vars[ix].decl;
 698
 699       if (decl)
 700         {
 701           saved = tree_cons (decl, build_int_cst (NULL_TREE, ix), saved);
 702           *fname_vars[ix].decl = NULL_TREE;
 703         }
 704     }
 705   if (saved || saved_function_name_decls)
 706     /* Normally they'll have been NULL, so only push if we've got a
 707        stack, or they are non-NULL.  */
 708     saved_function_name_decls = tree_cons (saved, NULL_TREE,
 709                                            saved_function_name_decls);
 710 }
 711
 712 /* Finish up the current bindings, adding them into the current function's
 713    statement tree.  This must be done _before_ finish_stmt_tree is called.
 714    If there is no current function, we must be at file scope and no statements
 715    are involved. Pop the previous bindings.  */
 716
 717 void
 718 finish_fname_decls (void)
 719 {
 720   unsigned ix;
 721   tree stmts = NULL_TREE;
 722   tree stack = saved_function_name_decls;
 723
 724   for (; stack && TREE_VALUE (stack); stack = TREE_CHAIN (stack))
 725     append_to_statement_list (TREE_VALUE (stack), &stmts);
 726
 727   if (stmts)
 728     {
 729       tree *bodyp = &DECL_SAVED_TREE (current_function_decl);
 730
 731       if (TREE_CODE (*bodyp) == BIND_EXPR)
 732         bodyp = &BIND_EXPR_BODY (*bodyp);
 733
 734       append_to_statement_list_force (*bodyp, &stmts);
 735       *bodyp = stmts;
 736     }
 737
 738   for (ix = 0; fname_vars[ix].decl; ix++)
 739     *fname_vars[ix].decl = NULL_TREE;
 740
 741   if (stack)
 742     {
 743       /* We had saved values, restore them.  */
 744       tree saved;
 745
 746       for (saved = TREE_PURPOSE (stack); saved; saved = TREE_CHAIN (saved))
 747         {
 748           tree decl = TREE_PURPOSE (saved);
 749           unsigned ix = TREE_INT_CST_LOW (TREE_VALUE (saved));
 750
 751           *fname_vars[ix].decl = decl;
 752         }
 753       stack = TREE_CHAIN (stack);
 754     }
 755   saved_function_name_decls = stack;
 756 }
 757
 758 /* Return the text name of the current function, suitably prettified
 759    by PRETTY_P.  Return string must be freed by caller.  */
 760
 761 const char *
 762 fname_as_string (int pretty_p)
 763 {
 764   const char *name = "top level";
 765   char *namep;
 766   int vrb = 2, len;
 767   cpp_string cstr = { 0, 0 }, strname;
 768
 769   if (!pretty_p)
 770     {
 771       name = "";
 772       vrb = 0;
 773     }
 774
 775   if (current_function_decl)
 776     name = lang_hooks.decl_printable_name (current_function_decl, vrb);
 777
 778   len = strlen (name) + 3; /* Two for '"'s.  One for NULL.  */
 779
 780   namep = XNEWVEC (char, len);
 781   snprintf (namep, len, "\"%s\"", name);
 782   strname.text = (unsigned char *) namep;
 783   strname.len = len - 1;
 784
 785   if (cpp_interpret_string (parse_in, &strname, 1, &cstr, false))
 786     {
 787       XDELETEVEC (namep);
 788       return (const char *) cstr.text;
 789     }
 790
 791   return namep;
 792 }
 793
 794 /* Expand DECL if it declares an entity not handled by the
 795    common code.  */
 796
 797 int
 798 c_expand_decl (tree decl)
 799 {
 800   if (TREE_CODE (decl) == VAR_DECL && !TREE_STATIC (decl))
 801     {
 802       /* Let the back-end know about this variable.  */
 803       if (!anon_aggr_type_p (TREE_TYPE (decl)))
 804         emit_local_var (decl);
 805       else
 806         expand_anon_union_decl (decl, NULL_TREE,
 807                                 DECL_ANON_UNION_ELEMS (decl));
 808     }
 809   else
 810     return 0;
 811
 812   return 1;
 813 }
 814
 815
 816 /* Return the VAR_DECL for a const char array naming the current
 817    function. If the VAR_DECL has not yet been created, create it
 818    now. RID indicates how it should be formatted and IDENTIFIER_NODE
 819    ID is its name (unfortunately C and C++ hold the RID values of
 820    keywords in different places, so we can't derive RID from ID in
 821    this language independent code.  */
 822
 823 tree
 824 fname_decl (unsigned int rid, tree id)
 825 {
 826   unsigned ix;
 827   tree decl = NULL_TREE;
 828
 829   for (ix = 0; fname_vars[ix].decl; ix++)
 830     if (fname_vars[ix].rid == rid)
 831       break;
 832
 833   decl = *fname_vars[ix].decl;
 834   if (!decl)
 835     {
 836       /* If a tree is built here, it would normally have the lineno of
 837          the current statement.  Later this tree will be moved to the
 838          beginning of the function and this line number will be wrong.
 839          To avoid this problem set the lineno to 0 here; that prevents
 840          it from appearing in the RTL.  */
 841       tree stmts;
 842       location_t saved_location = input_location;
 843 #ifdef USE_MAPPED_LOCATION
 844       input_location = UNKNOWN_LOCATION;
 845 #else
 846       input_line = 0;
 847 #endif
 848
 849       stmts = push_stmt_list ();
 850       decl = (*make_fname_decl) (id, fname_vars[ix].pretty);
 851       stmts = pop_stmt_list (stmts);
 852       if (!IS_EMPTY_STMT (stmts))
 853         saved_function_name_decls
 854           = tree_cons (decl, stmts, saved_function_name_decls);
 855       *fname_vars[ix].decl = decl;
 856       input_location = saved_location;
 857     }
 858   if (!ix && !current_function_decl)
 859     pedwarn ("%qD is not defined outside of function scope", decl);
 860
 861   return decl;
 862 }
 863
 864 /* Given a STRING_CST, give it a suitable array-of-chars data type.  */
 865
 866 tree
 867 fix_string_type (tree value)
 868 {
 869   const int wchar_bytes = TYPE_PRECISION (wchar_type_node) / BITS_PER_UNIT;
 870   const int wide_flag = TREE_TYPE (value) == wchar_array_type_node;
 871   int length = TREE_STRING_LENGTH (value);
 872   int nchars;
 873   tree e_type, i_type, a_type;
 874
 875   /* Compute the number of elements, for the array type.  */
 876   nchars = wide_flag ? length / wchar_bytes : length;
 877
 878   /* C89 2.2.4.1, C99 5.2.4.1 (Translation limits).  The analogous
 879      limit in C++98 Annex B is very large (65536) and is not normative,
 880      so we do not diagnose it (warn_overlength_strings is forced off
 881      in c_common_post_options).  */
 882   if (warn_overlength_strings)
 883     {
 884       const int nchars_max = flag_isoc99 ? 4095 : 509;
 885       const int relevant_std = flag_isoc99 ? 99 : 90;
 886       if (nchars - 1 > nchars_max)
 887         /* Translators: The %d after 'ISO C' will be 90 or 99.  Do not
 888            separate the %d from the 'C'.  'ISO' should not be
 889            translated, but it may be moved after 'C%d' in languages
 890            where modifiers follow nouns.  */
 891         pedwarn ("string length %qd is greater than the length %qd "
 892                  "ISO C%d compilers are required to support",
 893                  nchars - 1, nchars_max, relevant_std);
 894     }
 895
 896   /* Create the array type for the string constant.  The ISO C++
 897      standard says that a string literal has type `const char[N]' or
 898      `const wchar_t[N]'.  We use the same logic when invoked as a C
 899      front-end with -Wwrite-strings.
 900      ??? We should change the type of an expression depending on the
 901      state of a warning flag.  We should just be warning -- see how
 902      this is handled in the C++ front-end for the deprecated implicit
 903      conversion from string literals to `char*' or `wchar_t*'.
 904
 905      The C++ front end relies on TYPE_MAIN_VARIANT of a cv-qualified
 906      array type being the unqualified version of that type.
 907      Therefore, if we are constructing an array of const char, we must
 908      construct the matching unqualified array type first.  The C front
 909      end does not require this, but it does no harm, so we do it
 910      unconditionally.  */
 911   e_type = wide_flag ? wchar_type_node : char_type_node;
 912   i_type = build_index_type (build_int_cst (NULL_TREE, nchars - 1));
 913   a_type = build_array_type (e_type, i_type);
 914   if (c_dialect_cxx() || warn_write_strings)
 915     a_type = c_build_qualified_type (a_type, TYPE_QUAL_CONST);
 916
 917   TREE_TYPE (value) = a_type;
 918   TREE_CONSTANT (value) = 1;
 919   TREE_INVARIANT (value) = 1;
 920   TREE_READONLY (value) = 1;
 921   TREE_STATIC (value) = 1;
 922   return value;
 923 }
 924 \f
 925 /* Print a warning if a constant expression had overflow in folding.
 926    Invoke this function on every expression that the language
 927    requires to be a constant expression.
 928    Note the ANSI C standard says it is erroneous for a
 929    constant expression to overflow.  */
 930
 931 void
 932 constant_expression_warning (tree value)
 933 {
 934   if ((TREE_CODE (value) == INTEGER_CST || TREE_CODE (value) == REAL_CST
 935        || TREE_CODE (value) == FIXED_CST
 936        || TREE_CODE (value) == VECTOR_CST
 937        || TREE_CODE (value) == COMPLEX_CST)
 938       && TREE_OVERFLOW (value)
 939       && warn_overflow
 940       && pedantic)
 941     pedwarn ("overflow in constant expression");
 942 }
 943
 944 /* Print a warning if an expression had overflow in folding and its
 945    operands hadn't.
 946
 947    Invoke this function on every expression that
 948    (1) appears in the source code, and
 949    (2) is a constant expression that overflowed, and
 950    (3) is not already checked by convert_and_check;
 951    however, do not invoke this function on operands of explicit casts
 952    or when the expression is the result of an operator and any operand
 953    already overflowed.  */
 954
 955 void
 956 overflow_warning (tree value)
 957 {
 958   if (skip_evaluation) return;
 959
 960   switch (TREE_CODE (value))
 961     {
 962     case INTEGER_CST:
 963       warning (OPT_Woverflow, "integer overflow in expression");
 964       break;
 965
 966     case REAL_CST:
 967       warning (OPT_Woverflow, "floating point overflow in expression");
 968       break;
 969
 970     case FIXED_CST:
 971       warning (OPT_Woverflow, "fixed-point overflow in expression");
 972       break;
 973
 974     case VECTOR_CST:
 975       warning (OPT_Woverflow, "vector overflow in expression");
 976       break;
 977
 978     case COMPLEX_CST:
 979       if (TREE_CODE (TREE_REALPART (value)) == INTEGER_CST)
 980         warning (OPT_Woverflow, "complex integer overflow in expression");
 981       else if (TREE_CODE (TREE_REALPART (value)) == REAL_CST)
 982         warning (OPT_Woverflow, "complex floating point overflow in expression");
 983       break;
 984
 985     default:
 986       break;
 987     }
 988 }
 989
 990
 991 /* Warn about use of a logical || / && operator being used in a
 992    context where it is likely that the bitwise equivalent was intended
 993    by the programmer. CODE is the TREE_CODE of the operator, ARG1
 994    and ARG2 the arguments.  */
 995
 996 void
 997 warn_logical_operator (enum tree_code code, tree arg1, tree
 998     arg2)
 999 {
1000   switch (code)
1001     {
1002       case TRUTH_ANDIF_EXPR:
1003       case TRUTH_ORIF_EXPR:
1004       case TRUTH_OR_EXPR:
1005       case TRUTH_AND_EXPR:
1006         if (!TREE_NO_WARNING (arg1)
1007             && INTEGRAL_TYPE_P (TREE_TYPE (arg1))
1008             && !CONSTANT_CLASS_P (arg1)
1009             && TREE_CODE (arg2) == INTEGER_CST
1010             && !integer_zerop (arg2))
1011           {
1012             warning (OPT_Wlogical_op,
1013                      "logical %<%s%> with non-zero constant "
1014                      "will always evaluate as true",
1015                      ((code == TRUTH_ANDIF_EXPR)
1016                       || (code == TRUTH_AND_EXPR)) ? "&&" : "||");
1017             TREE_NO_WARNING (arg1) = true;
1018           }
1019         break;
1020       default:
1021         break;
1022     }
1023 }
1024
1025
1026 /* Print a warning about casts that might indicate violation
1027    of strict aliasing rules if -Wstrict-aliasing is used and
1028    strict aliasing mode is in effect. OTYPE is the original
1029    TREE_TYPE of EXPR, and TYPE the type we're casting to. */
1030
1031 bool
1032 strict_aliasing_warning (tree otype, tree type, tree expr)
1033 {
1034   if (!(flag_strict_aliasing && POINTER_TYPE_P (type)
1035         && POINTER_TYPE_P (otype) && !VOID_TYPE_P (TREE_TYPE (type))))
1036     return false;
1037
1038   if ((warn_strict_aliasing > 1) && TREE_CODE (expr) == ADDR_EXPR
1039       && (DECL_P (TREE_OPERAND (expr, 0))
1040           || handled_component_p (TREE_OPERAND (expr, 0))))
1041     {
1042       /* Casting the address of an object to non void pointer. Warn
1043          if the cast breaks type based aliasing.  */
1044       if (!COMPLETE_TYPE_P (TREE_TYPE (type)) && warn_strict_aliasing == 2)
1045         {
1046           warning (OPT_Wstrict_aliasing, "type-punning to incomplete type "
1047                    "might break strict-aliasing rules");
1048           return true;
1049         }
1050       else
1051         {
1052           /* warn_strict_aliasing >= 3.   This includes the default (3).
1053              Only warn if the cast is dereferenced immediately.  */
1054           alias_set_type set1 =
1055             get_alias_set (TREE_TYPE (TREE_OPERAND (expr, 0)));
1056           alias_set_type set2 = get_alias_set (TREE_TYPE (type));
1057
1058           if (!alias_sets_conflict_p (set1, set2))
1059             {
1060               warning (OPT_Wstrict_aliasing, "dereferencing type-punned "
1061                        "pointer will break strict-aliasing rules");
1062               return true;
1063             }
1064           else if (warn_strict_aliasing == 2
1065                    && !alias_sets_must_conflict_p (set1, set2))
1066             {
1067               warning (OPT_Wstrict_aliasing, "dereferencing type-punned "
1068                        "pointer might break strict-aliasing rules");
1069               return true;
1070             }
1071         }
1072     }
1073   else
1074     if ((warn_strict_aliasing == 1) && !VOID_TYPE_P (TREE_TYPE (otype)))
1075       {
1076         /* At this level, warn for any conversions, even if an address is
1077            not taken in the same statement.  This will likely produce many
1078            false positives, but could be useful to pinpoint problems that
1079            are not revealed at higher levels.  */
1080         alias_set_type set1 = get_alias_set (TREE_TYPE (otype));
1081         alias_set_type set2 = get_alias_set (TREE_TYPE (type));
1082         if (!COMPLETE_TYPE_P (type)
1083             || !alias_sets_must_conflict_p (set1, set2))
1084           {
1085             warning (OPT_Wstrict_aliasing, "dereferencing type-punned "
1086                      "pointer might break strict-aliasing rules");
1087             return true;
1088           }
1089       }
1090
1091   return false;
1092 }
1093
1094 /* Print a warning about if (); or if () .. else; constructs
1095    via the special empty statement node that we create.  INNER_THEN
1096    and INNER_ELSE are the statement lists of the if and the else
1097    block.  */
1098
1099 void
1100 empty_if_body_warning (tree inner_then, tree inner_else)
1101 {
1102   if (TREE_CODE (inner_then) == STATEMENT_LIST
1103       && STATEMENT_LIST_TAIL (inner_then))
1104     inner_then = STATEMENT_LIST_TAIL (inner_then)->stmt;
1105
1106   if (inner_else && TREE_CODE (inner_else) == STATEMENT_LIST
1107       && STATEMENT_LIST_TAIL (inner_else))
1108     inner_else = STATEMENT_LIST_TAIL (inner_else)->stmt;
1109
1110   if (IS_EMPTY_STMT (inner_then) && !inner_else)
1111     warning (OPT_Wempty_body, "%Hsuggest braces around empty body "
1112              "in an %<if%> statement", EXPR_LOCUS (inner_then));
1113
1114   else if (inner_else && IS_EMPTY_STMT (inner_else))
1115     warning (OPT_Wempty_body, "%Hsuggest braces around empty body "
1116              "in an %<else%> statement", EXPR_LOCUS (inner_else));
1117 }
1118
1119 /* Warn for unlikely, improbable, or stupid DECL declarations
1120    of `main'.  */
1121
1122 void
1123 check_main_parameter_types (tree decl)
1124 {
1125   tree args;
1126   int argct = 0;
1127
1128   for (args = TYPE_ARG_TYPES (TREE_TYPE (decl)); args;
1129       args = TREE_CHAIN (args))
1130    {
1131      tree type = args ? TREE_VALUE (args) : 0;
1132
1133      if (type == void_type_node || type == error_mark_node )
1134        break;
1135
1136      ++argct;
1137      switch (argct)
1138        {
1139        case 1:
1140          if (TYPE_MAIN_VARIANT (type) != integer_type_node)
1141            pedwarn ("first argument of %q+D should be %<int%>", decl);
1142          break;
1143
1144        case 2:
1145          if (TREE_CODE (type) != POINTER_TYPE
1146              || TREE_CODE (TREE_TYPE (type)) != POINTER_TYPE
1147              || (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (type)))
1148                  != char_type_node))
1149            pedwarn ("second argument of %q+D should be %<char **%>",
1150                     decl);
1151          break;
1152
1153        case 3:
1154          if (TREE_CODE (type) != POINTER_TYPE
1155              || TREE_CODE (TREE_TYPE (type)) != POINTER_TYPE
1156              || (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (type)))
1157                  != char_type_node))
1158            pedwarn ("third argument of %q+D should probably be "
1159                     "%<char **%>", decl);
1160          break;
1161        }
1162    }
1163
1164   /* It is intentional that this message does not mention the third
1165     argument because it's only mentioned in an appendix of the
1166     standard.  */
1167   if (argct > 0 && (argct < 2 || argct > 3))
1168    pedwarn ("%q+D takes only zero or two arguments", decl);
1169 }
1170
1171 /* True if vector types T1 and T2 can be converted to each other
1172    without an explicit cast.  If EMIT_LAX_NOTE is true, and T1 and T2
1173    can only be converted with -flax-vector-conversions yet that is not
1174    in effect, emit a note telling the user about that option if such
1175    a note has not previously been emitted.  */
1176 bool
1177 vector_types_convertible_p (const_tree t1, const_tree t2, bool emit_lax_note)
1178 {
1179   static bool emitted_lax_note = false;
1180   bool convertible_lax;
1181
1182   if ((targetm.vector_opaque_p (t1) || targetm.vector_opaque_p (t2))
1183       && tree_int_cst_equal (TYPE_SIZE (t1), TYPE_SIZE (t2)))
1184     return true;
1185
1186   convertible_lax =
1187     (tree_int_cst_equal (TYPE_SIZE (t1), TYPE_SIZE (t2))
1188      && (TREE_CODE (TREE_TYPE (t1)) != REAL_TYPE ||
1189          TYPE_PRECISION (t1) == TYPE_PRECISION (t2))
1190      && (INTEGRAL_TYPE_P (TREE_TYPE (t1))
1191          == INTEGRAL_TYPE_P (TREE_TYPE (t2))));
1192
1193   if (!convertible_lax || flag_lax_vector_conversions)
1194     return convertible_lax;
1195
1196   if (TYPE_VECTOR_SUBPARTS (t1) == TYPE_VECTOR_SUBPARTS (t2)
1197       && comptypes (TREE_TYPE (t1), TREE_TYPE (t2)))
1198     return true;
1199
1200   if (emit_lax_note && !emitted_lax_note)
1201     {
1202       emitted_lax_note = true;
1203       inform ("use -flax-vector-conversions to permit "
1204               "conversions between vectors with differing "
1205               "element types or numbers of subparts");
1206     }
1207
1208   return false;
1209 }
1210
1211 /* Warns if the conversion of EXPR to TYPE may alter a value.
1212    This is a helper function for warnings_for_convert_and_check.  */
1213
1214 static void
1215 conversion_warning (tree type, tree expr)
1216 {
1217   bool give_warning = false;
1218
1219   unsigned int formal_prec = TYPE_PRECISION (type);
1220
1221   if (!warn_conversion && !warn_sign_conversion)
1222     return;
1223
1224   if (TREE_CODE (expr) == REAL_CST || TREE_CODE (expr) == INTEGER_CST)
1225     {
1226       /* Warn for real constant that is not an exact integer converted
1227          to integer type.  */
1228       if (TREE_CODE (TREE_TYPE (expr)) == REAL_TYPE
1229           && TREE_CODE (type) == INTEGER_TYPE)
1230         {
1231           if (!real_isinteger (TREE_REAL_CST_PTR (expr), TYPE_MODE (TREE_TYPE (expr))))
1232             give_warning = true;
1233         }
1234       /* Warn for an integer constant that does not fit into integer type.  */
1235       else if (TREE_CODE (TREE_TYPE (expr)) == INTEGER_TYPE
1236                && TREE_CODE (type) == INTEGER_TYPE
1237                && !int_fits_type_p (expr, type))
1238         {
1239           if (TYPE_UNSIGNED (type) && !TYPE_UNSIGNED (TREE_TYPE (expr)))
1240             warning (OPT_Wsign_conversion,
1241                      "negative integer implicitly converted to unsigned type");
1242           else if (!TYPE_UNSIGNED (type) && TYPE_UNSIGNED (TREE_TYPE (expr)))
1243             warning (OPT_Wsign_conversion,
1244                      "conversion of unsigned constant value to negative integer");
1245           else
1246             give_warning = true;
1247         }
1248       else if (TREE_CODE (type) == REAL_TYPE)
1249         {
1250           /* Warn for an integer constant that does not fit into real type.  */
1251           if (TREE_CODE (TREE_TYPE (expr)) == INTEGER_TYPE)
1252             {
1253               REAL_VALUE_TYPE a = real_value_from_int_cst (0, expr);
1254               if (!exact_real_truncate (TYPE_MODE (type), &a))
1255                 give_warning = true;
1256             }
1257           /* Warn for a real constant that does not fit into a smaller
1258              real type.  */
1259           else if (TREE_CODE (TREE_TYPE (expr)) == REAL_TYPE
1260                    && formal_prec < TYPE_PRECISION (TREE_TYPE (expr)))
1261             {
1262               REAL_VALUE_TYPE a = TREE_REAL_CST (expr);
1263               if (!exact_real_truncate (TYPE_MODE (type), &a))
1264                 give_warning = true;
1265             }
1266         }
1267
1268       if (give_warning)
1269         warning (OPT_Wconversion,
1270                  "conversion to %qT alters %qT constant value",
1271                  type, TREE_TYPE (expr));
1272     }
1273   else /* 'expr' is not a constant.  */
1274     {
1275       /* Warn for real types converted to integer types.  */
1276       if (TREE_CODE (TREE_TYPE (expr)) == REAL_TYPE
1277           && TREE_CODE (type) == INTEGER_TYPE)
1278         give_warning = true;
1279
1280       else if (TREE_CODE (TREE_TYPE (expr)) == INTEGER_TYPE
1281                && TREE_CODE (type) == INTEGER_TYPE)
1282         {
1283           /* Don't warn about unsigned char y = 0xff, x = (int) y;  */
1284           expr = get_unwidened (expr, 0);
1285
1286           /* Warn for integer types converted to smaller integer types.  */
1287           if (formal_prec < TYPE_PRECISION (TREE_TYPE (expr)))
1288             give_warning = true;
1289
1290           /* When they are the same width but different signedness,
1291              then the value may change.  */
1292           else if ((formal_prec == TYPE_PRECISION (TREE_TYPE (expr))
1293                     && TYPE_UNSIGNED (TREE_TYPE (expr)) != TYPE_UNSIGNED (type))
1294                    /* Even when converted to a bigger type, if the type is
1295                       unsigned but expr is signed, then negative values
1296                       will be changed.  */
1297                    || (TYPE_UNSIGNED (type) && !TYPE_UNSIGNED (TREE_TYPE (expr))))
1298             warning (OPT_Wsign_conversion,
1299                      "conversion to %qT from %qT may change the sign of the result",
1300                      type, TREE_TYPE (expr));
1301         }
1302
1303       /* Warn for integer types converted to real types if and only if
1304          all the range of values of the integer type cannot be
1305          represented by the real type.  */
1306       else if (TREE_CODE (TREE_TYPE (expr)) == INTEGER_TYPE
1307                && TREE_CODE (type) == REAL_TYPE)
1308         {
1309           tree type_low_bound = TYPE_MIN_VALUE (TREE_TYPE (expr));
1310           tree type_high_bound = TYPE_MAX_VALUE (TREE_TYPE (expr));
1311           REAL_VALUE_TYPE real_low_bound = real_value_from_int_cst (0, type_low_bound);
1312           REAL_VALUE_TYPE real_high_bound = real_value_from_int_cst (0, type_high_bound);
1313
1314           if (!exact_real_truncate (TYPE_MODE (type), &real_low_bound)
1315               || !exact_real_truncate (TYPE_MODE (type), &real_high_bound))
1316             give_warning = true;
1317         }
1318
1319       /* Warn for real types converted to smaller real types.  */
1320       else if (TREE_CODE (TREE_TYPE (expr)) == REAL_TYPE
1321                && TREE_CODE (type) == REAL_TYPE
1322                && formal_prec < TYPE_PRECISION (TREE_TYPE (expr)))
1323         give_warning = true;
1324
1325
1326       if (give_warning)
1327         warning (OPT_Wconversion,
1328                  "conversion to %qT from %qT may alter its value",
1329                  type, TREE_TYPE (expr));
1330     }
1331 }
1332
1333 /* Produce warnings after a conversion. RESULT is the result of
1334    converting EXPR to TYPE.  This is a helper function for
1335    convert_and_check and cp_convert_and_check.  */
1336
1337 void
1338 warnings_for_convert_and_check (tree type, tree expr, tree result)
1339 {
1340   if (TREE_CODE (expr) == INTEGER_CST
1341       && (TREE_CODE (type) == INTEGER_TYPE
1342           || TREE_CODE (type) == ENUMERAL_TYPE)
1343       && !int_fits_type_p (expr, type))
1344     {
1345       /* Do not diagnose overflow in a constant expression merely
1346          because a conversion overflowed.  */
1347       if (TREE_OVERFLOW (result))
1348         TREE_OVERFLOW (result) = TREE_OVERFLOW (expr);
1349
1350       if (TYPE_UNSIGNED (type))
1351         {
1352           /* This detects cases like converting -129 or 256 to
1353              unsigned char.  */
1354           if (!int_fits_type_p (expr, c_common_signed_type (type)))
1355             warning (OPT_Woverflow,
1356                      "large integer implicitly truncated to unsigned type");
1357           else
1358             conversion_warning (type, expr);
1359         }
1360       else if (!int_fits_type_p (expr, c_common_unsigned_type (type)))
1361         warning (OPT_Woverflow,
1362                  "overflow in implicit constant conversion");
1363       /* No warning for converting 0x80000000 to int.  */
1364       else if (pedantic
1365                && (TREE_CODE (TREE_TYPE (expr)) != INTEGER_TYPE
1366                    || TYPE_PRECISION (TREE_TYPE (expr))
1367                    != TYPE_PRECISION (type)))
1368         warning (OPT_Woverflow,
1369                  "overflow in implicit constant conversion");
1370
1371       else
1372         conversion_warning (type, expr);
1373     }
1374   else if ((TREE_CODE (result) == INTEGER_CST
1375             || TREE_CODE (result) == FIXED_CST) && TREE_OVERFLOW (result))
1376     warning (OPT_Woverflow,
1377              "overflow in implicit constant conversion");
1378   else
1379     conversion_warning (type, expr);
1380 }
1381
1382
1383 /* Convert EXPR to TYPE, warning about conversion problems with constants.
1384    Invoke this function on every expression that is converted implicitly,
1385    i.e. because of language rules and not because of an explicit cast.  */
1386
1387 tree
1388 convert_and_check (tree type, tree expr)
1389 {
1390   tree result;
1391
1392   if (TREE_TYPE (expr) == type)
1393     return expr;
1394
1395   result = convert (type, expr);
1396
1397   if (!skip_evaluation && !TREE_OVERFLOW_P (expr) && result != error_mark_node)
1398     warnings_for_convert_and_check (type, expr, result);
1399
1400   return result;
1401 }
1402 \f
1403 /* A node in a list that describes references to variables (EXPR), which are
1404    either read accesses if WRITER is zero, or write accesses, in which case
1405    WRITER is the parent of EXPR.  */
1406 struct tlist
1407 {
1408   struct tlist *next;
1409   tree expr, writer;
1410 };
1411
1412 /* Used to implement a cache the results of a call to verify_tree.  We only
1413    use this for SAVE_EXPRs.  */
1414 struct tlist_cache
1415 {
1416   struct tlist_cache *next;
1417   struct tlist *cache_before_sp;
1418   struct tlist *cache_after_sp;
1419   tree expr;
1420 };
1421
1422 /* Obstack to use when allocating tlist structures, and corresponding
1423    firstobj.  */
1424 static struct obstack tlist_obstack;
1425 static char *tlist_firstobj = 0;
1426
1427 /* Keep track of the identifiers we've warned about, so we can avoid duplicate
1428    warnings.  */
1429 static struct tlist *warned_ids;
1430 /* SAVE_EXPRs need special treatment.  We process them only once and then
1431    cache the results.  */
1432 static struct tlist_cache *save_expr_cache;
1433
1434 static void add_tlist (struct tlist **, struct tlist *, tree, int);
1435 static void merge_tlist (struct tlist **, struct tlist *, int);
1436 static void verify_tree (tree, struct tlist **, struct tlist **, tree);
1437 static int warning_candidate_p (tree);
1438 static void warn_for_collisions (struct tlist *);
1439 static void warn_for_collisions_1 (tree, tree, struct tlist *, int);
1440 static struct tlist *new_tlist (struct tlist *, tree, tree);
1441
1442 /* Create a new struct tlist and fill in its fields.  */
1443 static struct tlist *
1444 new_tlist (struct tlist *next, tree t, tree writer)
1445 {
1446   struct tlist *l;
1447   l = XOBNEW (&tlist_obstack, struct tlist);
1448   l->next = next;
1449   l->expr = t;
1450   l->writer = writer;
1451   return l;
1452 }
1453
1454 /* Add duplicates of the nodes found in ADD to the list *TO.  If EXCLUDE_WRITER
1455    is nonnull, we ignore any node we find which has a writer equal to it.  */
1456
1457 static void
1458 add_tlist (struct tlist **to, struct tlist *add, tree exclude_writer, int copy)
1459 {
1460   while (add)
1461     {
1462       struct tlist *next = add->next;
1463       if (!copy)
1464         add->next = *to;
1465       if (!exclude_writer || add->writer != exclude_writer)
1466         *to = copy ? new_tlist (*to, add->expr, add->writer) : add;
1467       add = next;
1468     }
1469 }
1470
1471 /* Merge the nodes of ADD into TO.  This merging process is done so that for
1472    each variable that already exists in TO, no new node is added; however if
1473    there is a write access recorded in ADD, and an occurrence on TO is only
1474    a read access, then the occurrence in TO will be modified to record the
1475    write.  */
1476
1477 static void
1478 merge_tlist (struct tlist **to, struct tlist *add, int copy)
1479 {
1480   struct tlist **end = to;
1481
1482   while (*end)
1483     end = &(*end)->next;
1484
1485   while (add)
1486     {
1487       int found = 0;
1488       struct tlist *tmp2;
1489       struct tlist *next = add->next;
1490
1491       for (tmp2 = *to; tmp2; tmp2 = tmp2->next)
1492         if (tmp2->expr == add->expr)
1493           {
1494             found = 1;
1495             if (!tmp2->writer)
1496               tmp2->writer = add->writer;
1497           }
1498       if (!found)
1499         {
1500           *end = copy ? add : new_tlist (NULL, add->expr, add->writer);
1501           end = &(*end)->next;
1502           *end = 0;
1503         }
1504       add = next;
1505     }
1506 }
1507
1508 /* WRITTEN is a variable, WRITER is its parent.  Warn if any of the variable
1509    references in list LIST conflict with it, excluding reads if ONLY writers
1510    is nonzero.  */
1511
1512 static void
1513 warn_for_collisions_1 (tree written, tree writer, struct tlist *list,
1514                        int only_writes)
1515 {
1516   struct tlist *tmp;
1517
1518   /* Avoid duplicate warnings.  */
1519   for (tmp = warned_ids; tmp; tmp = tmp->next)
1520     if (tmp->expr == written)
1521       return;
1522
1523   while (list)
1524     {
1525       if (list->expr == written
1526           && list->writer != writer
1527           && (!only_writes || list->writer)
1528           && DECL_NAME (list->expr))
1529         {
1530           warned_ids = new_tlist (warned_ids, written, NULL_TREE);
1531           warning (0, "operation on %qE may be undefined", list->expr);
1532         }
1533       list = list->next;
1534     }
1535 }
1536
1537 /* Given a list LIST of references to variables, find whether any of these
1538    can cause conflicts due to missing sequence points.  */
1539
1540 static void
1541 warn_for_collisions (struct tlist *list)
1542 {
1543   struct tlist *tmp;
1544
1545   for (tmp = list; tmp; tmp = tmp->next)
1546     {
1547       if (tmp->writer)
1548         warn_for_collisions_1 (tmp->expr, tmp->writer, list, 0);
1549     }
1550 }
1551
1552 /* Return nonzero if X is a tree that can be verified by the sequence point
1553    warnings.  */
1554 static int
1555 warning_candidate_p (tree x)
1556 {
1557   return TREE_CODE (x) == VAR_DECL || TREE_CODE (x) == PARM_DECL;
1558 }
1559
1560 /* Walk the tree X, and record accesses to variables.  If X is written by the
1561    parent tree, WRITER is the parent.
1562    We store accesses in one of the two lists: PBEFORE_SP, and PNO_SP.  If this
1563    expression or its only operand forces a sequence point, then everything up
1564    to the sequence point is stored in PBEFORE_SP.  Everything else gets stored
1565    in PNO_SP.
1566    Once we return, we will have emitted warnings if any subexpression before
1567    such a sequence point could be undefined.  On a higher level, however, the
1568    sequence point may not be relevant, and we'll merge the two lists.
1569
1570    Example: (b++, a) + b;
1571    The call that processes the COMPOUND_EXPR will store the increment of B
1572    in PBEFORE_SP, and the use of A in PNO_SP.  The higher-level call that
1573    processes the PLUS_EXPR will need to merge the two lists so that
1574    eventually, all accesses end up on the same list (and we'll warn about the
1575    unordered subexpressions b++ and b.
1576
1577    A note on merging.  If we modify the former example so that our expression
1578    becomes
1579      (b++, b) + a
1580    care must be taken not simply to add all three expressions into the final
1581    PNO_SP list.  The function merge_tlist takes care of that by merging the
1582    before-SP list of the COMPOUND_EXPR into its after-SP list in a special
1583    way, so that no more than one access to B is recorded.  */
1584
1585 static void
1586 verify_tree (tree x, struct tlist **pbefore_sp, struct tlist **pno_sp,
1587              tree writer)
1588 {
1589   struct tlist *tmp_before, *tmp_nosp, *tmp_list2, *tmp_list3;
1590   enum tree_code code;
1591   enum tree_code_class cl;
1592
1593   /* X may be NULL if it is the operand of an empty statement expression
1594      ({ }).  */
1595   if (x == NULL)
1596     return;
1597
1598  restart:
1599   code = TREE_CODE (x);
1600   cl = TREE_CODE_CLASS (code);
1601
1602   if (warning_candidate_p (x))
1603     {
1604       *pno_sp = new_tlist (*pno_sp, x, writer);
1605       return;
1606     }
1607
1608   switch (code)
1609     {
1610     case CONSTRUCTOR:
1611       return;
1612
1613     case COMPOUND_EXPR:
1614     case TRUTH_ANDIF_EXPR:
1615     case TRUTH_ORIF_EXPR:
1616       tmp_before = tmp_nosp = tmp_list3 = 0;
1617       verify_tree (TREE_OPERAND (x, 0), &tmp_before, &tmp_nosp, NULL_TREE);
1618       warn_for_collisions (tmp_nosp);
1619       merge_tlist (pbefore_sp, tmp_before, 0);
1620       merge_tlist (pbefore_sp, tmp_nosp, 0);
1621       verify_tree (TREE_OPERAND (x, 1), &tmp_list3, pno_sp, NULL_TREE);
1622       merge_tlist (pbefore_sp, tmp_list3, 0);
1623       return;
1624
1625     case COND_EXPR:
1626       tmp_before = tmp_list2 = 0;
1627       verify_tree (TREE_OPERAND (x, 0), &tmp_before, &tmp_list2, NULL_TREE);
1628       warn_for_collisions (tmp_list2);
1629       merge_tlist (pbefore_sp, tmp_before, 0);
1630       merge_tlist (pbefore_sp, tmp_list2, 1);
1631
1632       tmp_list3 = tmp_nosp = 0;
1633       verify_tree (TREE_OPERAND (x, 1), &tmp_list3, &tmp_nosp, NULL_TREE);
1634       warn_for_collisions (tmp_nosp);
1635       merge_tlist (pbefore_sp, tmp_list3, 0);
1636
1637       tmp_list3 = tmp_list2 = 0;
1638       verify_tree (TREE_OPERAND (x, 2), &tmp_list3, &tmp_list2, NULL_TREE);
1639       warn_for_collisions (tmp_list2);
1640       merge_tlist (pbefore_sp, tmp_list3, 0);
1641       /* Rather than add both tmp_nosp and tmp_list2, we have to merge the
1642          two first, to avoid warning for (a ? b++ : b++).  */
1643       merge_tlist (&tmp_nosp, tmp_list2, 0);
1644       add_tlist (pno_sp, tmp_nosp, NULL_TREE, 0);
1645       return;
1646
1647     case PREDECREMENT_EXPR:
1648     case PREINCREMENT_EXPR:
1649     case POSTDECREMENT_EXPR:
1650     case POSTINCREMENT_EXPR:
1651       verify_tree (TREE_OPERAND (x, 0), pno_sp, pno_sp, x);
1652       return;
1653
1654     case MODIFY_EXPR:
1655       tmp_before = tmp_nosp = tmp_list3 = 0;
1656       verify_tree (TREE_OPERAND (x, 1), &tmp_before, &tmp_nosp, NULL_TREE);
1657       verify_tree (TREE_OPERAND (x, 0), &tmp_list3, &tmp_list3, x);
1658       /* Expressions inside the LHS are not ordered wrt. the sequence points
1659          in the RHS.  Example:
1660            *a = (a++, 2)
1661          Despite the fact that the modification of "a" is in the before_sp
1662          list (tmp_before), it conflicts with the use of "a" in the LHS.
1663          We can handle this by adding the contents of tmp_list3
1664          to those of tmp_before, and redoing the collision warnings for that
1665          list.  */
1666       add_tlist (&tmp_before, tmp_list3, x, 1);
1667       warn_for_collisions (tmp_before);
1668       /* Exclude the LHS itself here; we first have to merge it into the
1669          tmp_nosp list.  This is done to avoid warning for "a = a"; if we
1670          didn't exclude the LHS, we'd get it twice, once as a read and once
1671          as a write.  */
1672       add_tlist (pno_sp, tmp_list3, x, 0);
1673       warn_for_collisions_1 (TREE_OPERAND (x, 0), x, tmp_nosp, 1);
1674
1675       merge_tlist (pbefore_sp, tmp_before, 0);
1676       if (warning_candidate_p (TREE_OPERAND (x, 0)))
1677         merge_tlist (&tmp_nosp, new_tlist (NULL, TREE_OPERAND (x, 0), x), 0);
1678       add_tlist (pno_sp, tmp_nosp, NULL_TREE, 1);
1679       return;
1680
1681     case CALL_EXPR:
1682       /* We need to warn about conflicts among arguments and conflicts between
1683          args and the function address.  Side effects of the function address,
1684          however, are not ordered by the sequence point of the call.  */
1685       {
1686         call_expr_arg_iterator iter;
1687         tree arg;
1688         tmp_before = tmp_nosp = 0;
1689         verify_tree (CALL_EXPR_FN (x), &tmp_before, &tmp_nosp, NULL_TREE);
1690         FOR_EACH_CALL_EXPR_ARG (arg, iter, x)
1691           {
1692             tmp_list2 = tmp_list3 = 0;
1693             verify_tree (arg, &tmp_list2, &tmp_list3, NULL_TREE);
1694             merge_tlist (&tmp_list3, tmp_list2, 0);
1695             add_tlist (&tmp_before, tmp_list3, NULL_TREE, 0);
1696           }
1697         add_tlist (&tmp_before, tmp_nosp, NULL_TREE, 0);
1698         warn_for_collisions (tmp_before);
1699         add_tlist (pbefore_sp, tmp_before, NULL_TREE, 0);
1700         return;
1701       }
1702
1703     case TREE_LIST:
1704       /* Scan all the list, e.g. indices of multi dimensional array.  */
1705       while (x)
1706         {
1707           tmp_before = tmp_nosp = 0;
1708           verify_tree (TREE_VALUE (x), &tmp_before, &tmp_nosp, NULL_TREE);
1709           merge_tlist (&tmp_nosp, tmp_before, 0);
1710           add_tlist (pno_sp, tmp_nosp, NULL_TREE, 0);
1711           x = TREE_CHAIN (x);
1712         }
1713       return;
1714
1715     case SAVE_EXPR:
1716       {
1717         struct tlist_cache *t;
1718         for (t = save_expr_cache; t; t = t->next)
1719           if (t->expr == x)
1720             break;
1721
1722         if (!t)
1723           {
1724             t = XOBNEW (&tlist_obstack, struct tlist_cache);
1725             t->next = save_expr_cache;
1726             t->expr = x;
1727             save_expr_cache = t;
1728
1729             tmp_before = tmp_nosp = 0;
1730             verify_tree (TREE_OPERAND (x, 0), &tmp_before, &tmp_nosp, NULL_TREE);
1731             warn_for_collisions (tmp_nosp);
1732
1733             tmp_list3 = 0;
1734             while (tmp_nosp)
1735               {
1736                 struct tlist *t = tmp_nosp;
1737                 tmp_nosp = t->next;
1738                 merge_tlist (&tmp_list3, t, 0);
1739               }
1740             t->cache_before_sp = tmp_before;
1741             t->cache_after_sp = tmp_list3;
1742           }
1743         merge_tlist (pbefore_sp, t->cache_before_sp, 1);
1744         add_tlist (pno_sp, t->cache_after_sp, NULL_TREE, 1);
1745         return;
1746       }
1747
1748     default:
1749       /* For other expressions, simply recurse on their operands.
1750          Manual tail recursion for unary expressions.
1751          Other non-expressions need not be processed.  */
1752       if (cl == tcc_unary)
1753         {
1754           x = TREE_OPERAND (x, 0);
1755           writer = 0;
1756           goto restart;
1757         }
1758       else if (IS_EXPR_CODE_CLASS (cl))
1759         {
1760           int lp;
1761           int max = TREE_OPERAND_LENGTH (x);
1762           for (lp = 0; lp < max; lp++)
1763             {
1764               tmp_before = tmp_nosp = 0;
1765               verify_tree (TREE_OPERAND (x, lp), &tmp_before, &tmp_nosp, 0);
1766               merge_tlist (&tmp_nosp, tmp_before, 0);
1767               add_tlist (pno_sp, tmp_nosp, NULL_TREE, 0);
1768             }
1769         }
1770       return;
1771     }
1772 }
1773
1774 /* Try to warn for undefined behavior in EXPR due to missing sequence
1775    points.  */
1776
1777 void
1778 verify_sequence_points (tree expr)
1779 {
1780   struct tlist *before_sp = 0, *after_sp = 0;
1781
1782   warned_ids = 0;
1783   save_expr_cache = 0;
1784   if (tlist_firstobj == 0)
1785     {
1786       gcc_obstack_init (&tlist_obstack);
1787       tlist_firstobj = (char *) obstack_alloc (&tlist_obstack, 0);
1788     }
1789
1790   verify_tree (expr, &before_sp, &after_sp, 0);
1791   warn_for_collisions (after_sp);
1792   obstack_free (&tlist_obstack, tlist_firstobj);
1793 }
1794 \f
1795 /* Validate the expression after `case' and apply default promotions.  */
1796
1797 static tree
1798 check_case_value (tree value)
1799 {
1800   if (value == NULL_TREE)
1801     return value;
1802
1803   /* ??? Can we ever get nops here for a valid case value?  We
1804      shouldn't for C.  */
1805   STRIP_TYPE_NOPS (value);
1806   /* In C++, the following is allowed:
1807
1808        const int i = 3;
1809        switch (...) { case i: ... }
1810
1811      So, we try to reduce the VALUE to a constant that way.  */
1812   if (c_dialect_cxx ())
1813     {
1814       value = decl_constant_value (value);
1815       STRIP_TYPE_NOPS (value);
1816       value = fold (value);
1817     }
1818
1819   if (TREE_CODE (value) == INTEGER_CST)
1820     /* Promote char or short to int.  */
1821     value = perform_integral_promotions (value);
1822   else if (value != error_mark_node)
1823     {
1824       error ("case label does not reduce to an integer constant");
1825       value = error_mark_node;
1826     }
1827
1828   constant_expression_warning (value);
1829
1830   return value;
1831 }
1832 \f
1833 /* See if the case values LOW and HIGH are in the range of the original
1834    type (i.e. before the default conversion to int) of the switch testing
1835    expression.
1836    TYPE is the promoted type of the testing expression, and ORIG_TYPE is
1837    the type before promoting it.  CASE_LOW_P is a pointer to the lower
1838    bound of the case label, and CASE_HIGH_P is the upper bound or NULL
1839    if the case is not a case range.
1840    The caller has to make sure that we are not called with NULL for
1841    CASE_LOW_P (i.e. the default case).
1842    Returns true if the case label is in range of ORIG_TYPE (saturated or
1843    untouched) or false if the label is out of range.  */
1844
1845 static bool
1846 check_case_bounds (tree type, tree orig_type,
1847                    tree *case_low_p, tree *case_high_p)
1848 {
1849   tree min_value, max_value;
1850   tree case_low = *case_low_p;
1851   tree case_high = case_high_p ? *case_high_p : case_low;
1852
1853   /* If there was a problem with the original type, do nothing.  */
1854   if (orig_type == error_mark_node)
1855     return true;
1856
1857   min_value = TYPE_MIN_VALUE (orig_type);
1858   max_value = TYPE_MAX_VALUE (orig_type);
1859
1860   /* Case label is less than minimum for type.  */
1861   if (tree_int_cst_compare (case_low, min_value) < 0
1862       && tree_int_cst_compare (case_high, min_value) < 0)
1863     {
1864       warning (0, "case label value is less than minimum value for type");
1865       return false;
1866     }
1867
1868   /* Case value is greater than maximum for type.  */
1869   if (tree_int_cst_compare (case_low, max_value) > 0
1870       && tree_int_cst_compare (case_high, max_value) > 0)
1871     {
1872       warning (0, "case label value exceeds maximum value for type");
1873       return false;
1874     }
1875
1876   /* Saturate lower case label value to minimum.  */
1877   if (tree_int_cst_compare (case_high, min_value) >= 0
1878       && tree_int_cst_compare (case_low, min_value) < 0)
1879     {
1880       warning (0, "lower value in case label range"
1881                " less than minimum value for type");
1882       case_low = min_value;
1883     }
1884
1885   /* Saturate upper case label value to maximum.  */
1886   if (tree_int_cst_compare (case_low, max_value) <= 0
1887       && tree_int_cst_compare (case_high, max_value) > 0)
1888     {
1889       warning (0, "upper value in case label range"
1890                " exceeds maximum value for type");
1891       case_high = max_value;
1892     }
1893
1894   if (*case_low_p != case_low)
1895     *case_low_p = convert (type, case_low);
1896   if (case_high_p && *case_high_p != case_high)
1897     *case_high_p = convert (type, case_high);
1898
1899   return true;
1900 }
1901 \f
1902 /* Return an integer type with BITS bits of precision,
1903    that is unsigned if UNSIGNEDP is nonzero, otherwise signed.  */
1904
1905 tree
1906 c_common_type_for_size (unsigned int bits, int unsignedp)
1907 {
1908   if (bits == TYPE_PRECISION (integer_type_node))
1909     return unsignedp ? unsigned_type_node : integer_type_node;
1910
1911   if (bits == TYPE_PRECISION (signed_char_type_node))
1912     return unsignedp ? unsigned_char_type_node : signed_char_type_node;
1913
1914   if (bits == TYPE_PRECISION (short_integer_type_node))
1915     return unsignedp ? short_unsigned_type_node : short_integer_type_node;
1916
1917   if (bits == TYPE_PRECISION (long_integer_type_node))
1918     return unsignedp ? long_unsigned_type_node : long_integer_type_node;
1919
1920   if (bits == TYPE_PRECISION (long_long_integer_type_node))
1921     return (unsignedp ? long_long_unsigned_type_node
1922             : long_long_integer_type_node);
1923
1924   if (bits == TYPE_PRECISION (widest_integer_literal_type_node))
1925     return (unsignedp ? widest_unsigned_literal_type_node
1926             : widest_integer_literal_type_node);
1927
1928   if (bits <= TYPE_PRECISION (intQI_type_node))
1929     return unsignedp ? unsigned_intQI_type_node : intQI_type_node;
1930
1931   if (bits <= TYPE_PRECISION (intHI_type_node))
1932     return unsignedp ? unsigned_intHI_type_node : intHI_type_node;
1933
1934   if (bits <= TYPE_PRECISION (intSI_type_node))
1935     return unsignedp ? unsigned_intSI_type_node : intSI_type_node;
1936
1937   if (bits <= TYPE_PRECISION (intDI_type_node))
1938     return unsignedp ? unsigned_intDI_type_node : intDI_type_node;
1939
1940   return 0;
1941 }
1942
1943 /* Return a fixed-point type that has at least IBIT ibits and FBIT fbits
1944    that is unsigned if UNSIGNEDP is nonzero, otherwise signed;
1945    and saturating if SATP is nonzero, otherwise not saturating.  */
1946
1947 tree
1948 c_common_fixed_point_type_for_size (unsigned int ibit, unsigned int fbit,
1949                                     int unsignedp, int satp)
1950 {
1951   enum machine_mode mode;
1952   if (ibit == 0)
1953     mode = unsignedp ? UQQmode : QQmode;
1954   else
1955     mode = unsignedp ? UHAmode : HAmode;
1956
1957   for (; mode != VOIDmode; mode = GET_MODE_WIDER_MODE (mode))
1958     if (GET_MODE_IBIT (mode) >= ibit && GET_MODE_FBIT (mode) >= fbit)
1959       break;
1960
1961   if (mode == VOIDmode || !targetm.scalar_mode_supported_p (mode))
1962     {
1963       sorry ("GCC cannot support operators with integer types and "
1964              "fixed-point types that have too many integral and "
1965              "fractional bits together");
1966       return 0;
1967     }
1968
1969   return c_common_type_for_mode (mode, satp);
1970 }
1971
1972 /* Used for communication between c_common_type_for_mode and
1973    c_register_builtin_type.  */
1974 static GTY(()) tree registered_builtin_types;
1975
1976 /* Return a data type that has machine mode MODE.
1977    If the mode is an integer,
1978    then UNSIGNEDP selects between signed and unsigned types.
1979    If the mode is a fixed-point mode,
1980    then UNSIGNEDP selects between saturating and nonsaturating types.  */
1981
1982 tree
1983 c_common_type_for_mode (enum machine_mode mode, int unsignedp)
1984 {
1985   tree t;
1986
1987   if (mode == TYPE_MODE (integer_type_node))
1988     return unsignedp ? unsigned_type_node : integer_type_node;
1989
1990   if (mode == TYPE_MODE (signed_char_type_node))
1991     return unsignedp ? unsigned_char_type_node : signed_char_type_node;
1992
1993   if (mode == TYPE_MODE (short_integer_type_node))
1994     return unsignedp ? short_unsigned_type_node : short_integer_type_node;
1995
1996   if (mode == TYPE_MODE (long_integer_type_node))
1997     return unsignedp ? long_unsigned_type_node : long_integer_type_node;
1998
1999   if (mode == TYPE_MODE (long_long_integer_type_node))
2000     return unsignedp ? long_long_unsigned_type_node : long_long_integer_type_node;
2001
2002   if (mode == TYPE_MODE (widest_integer_literal_type_node))
2003     return unsignedp ? widest_unsigned_literal_type_node
2004                      : widest_integer_literal_type_node;
2005
2006   if (mode == QImode)
2007     return unsignedp ? unsigned_intQI_type_node : intQI_type_node;
2008
2009   if (mode == HImode)
2010     return unsignedp ? unsigned_intHI_type_node : intHI_type_node;
2011
2012   if (mode == SImode)
2013     return unsignedp ? unsigned_intSI_type_node : intSI_type_node;
2014
2015   if (mode == DImode)
2016     return unsignedp ? unsigned_intDI_type_node : intDI_type_node;
2017
2018 #if HOST_BITS_PER_WIDE_INT >= 64
2019   if (mode == TYPE_MODE (intTI_type_node))
2020     return unsignedp ? unsigned_intTI_type_node : intTI_type_node;
2021 #endif
2022
2023   if (mode == TYPE_MODE (float_type_node))
2024     return float_type_node;
2025
2026   if (mode == TYPE_MODE (double_type_node))
2027     return double_type_node;
2028
2029   if (mode == TYPE_MODE (long_double_type_node))
2030     return long_double_type_node;
2031
2032   if (mode == TYPE_MODE (void_type_node))
2033     return void_type_node;
2034
2035   if (mode == TYPE_MODE (build_pointer_type (char_type_node)))
2036     return (unsignedp
2037             ? make_unsigned_type (GET_MODE_PRECISION (mode))
2038             : make_signed_type (GET_MODE_PRECISION (mode)));
2039
2040   if (mode == TYPE_MODE (build_pointer_type (integer_type_node)))
2041     return (unsignedp
2042             ? make_unsigned_type (GET_MODE_PRECISION (mode))
2043             : make_signed_type (GET_MODE_PRECISION (mode)));
2044
2045   if (COMPLEX_MODE_P (mode))
2046     {
2047       enum machine_mode inner_mode;
2048       tree inner_type;
2049
2050       if (mode == TYPE_MODE (complex_float_type_node))
2051         return complex_float_type_node;
2052       if (mode == TYPE_MODE (complex_double_type_node))
2053         return complex_double_type_node;
2054       if (mode == TYPE_MODE (complex_long_double_type_node))
2055         return complex_long_double_type_node;
2056
2057       if (mode == TYPE_MODE (complex_integer_type_node) && !unsignedp)
2058         return complex_integer_type_node;
2059
2060       inner_mode = GET_MODE_INNER (mode);
2061       inner_type = c_common_type_for_mode (inner_mode, unsignedp);
2062       if (inner_type != NULL_TREE)
2063         return build_complex_type (inner_type);
2064     }
2065   else if (VECTOR_MODE_P (mode))
2066     {
2067       enum machine_mode inner_mode = GET_MODE_INNER (mode);
2068       tree inner_type = c_common_type_for_mode (inner_mode, unsignedp);
2069       if (inner_type != NULL_TREE)
2070         return build_vector_type_for_mode (inner_type, mode);
2071     }
2072
2073   if (mode == TYPE_MODE (dfloat32_type_node))
2074     return dfloat32_type_node;
2075   if (mode == TYPE_MODE (dfloat64_type_node))
2076     return dfloat64_type_node;
2077   if (mode == TYPE_MODE (dfloat128_type_node))
2078     return dfloat128_type_node;
2079
2080   if (ALL_SCALAR_FIXED_POINT_MODE_P (mode))
2081     {
2082       if (mode == TYPE_MODE (short_fract_type_node))
2083         return unsignedp ? sat_short_fract_type_node : short_fract_type_node;
2084       if (mode == TYPE_MODE (fract_type_node))
2085         return unsignedp ? sat_fract_type_node : fract_type_node;
2086       if (mode == TYPE_MODE (long_fract_type_node))
2087         return unsignedp ? sat_long_fract_type_node : long_fract_type_node;
2088       if (mode == TYPE_MODE (long_long_fract_type_node))
2089         return unsignedp ? sat_long_long_fract_type_node
2090                          : long_long_fract_type_node;
2091
2092       if (mode == TYPE_MODE (unsigned_short_fract_type_node))
2093         return unsignedp ? sat_unsigned_short_fract_type_node
2094                          : unsigned_short_fract_type_node;
2095       if (mode == TYPE_MODE (unsigned_fract_type_node))
2096         return unsignedp ? sat_unsigned_fract_type_node
2097                          : unsigned_fract_type_node;
2098       if (mode == TYPE_MODE (unsigned_long_fract_type_node))
2099         return unsignedp ? sat_unsigned_long_fract_type_node
2100                          : unsigned_long_fract_type_node;
2101       if (mode == TYPE_MODE (unsigned_long_long_fract_type_node))
2102         return unsignedp ? sat_unsigned_long_long_fract_type_node
2103                          : unsigned_long_long_fract_type_node;
2104
2105       if (mode == TYPE_MODE (short_accum_type_node))
2106         return unsignedp ? sat_short_accum_type_node : short_accum_type_node;
2107       if (mode == TYPE_MODE (accum_type_node))
2108         return unsignedp ? sat_accum_type_node : accum_type_node;
2109       if (mode == TYPE_MODE (long_accum_type_node))
2110         return unsignedp ? sat_long_accum_type_node : long_accum_type_node;
2111       if (mode == TYPE_MODE (long_long_accum_type_node))
2112         return unsignedp ? sat_long_long_accum_type_node
2113                          : long_long_accum_type_node;
2114
2115       if (mode == TYPE_MODE (unsigned_short_accum_type_node))
2116         return unsignedp ? sat_unsigned_short_accum_type_node
2117                          : unsigned_short_accum_type_node;
2118       if (mode == TYPE_MODE (unsigned_accum_type_node))
2119         return unsignedp ? sat_unsigned_accum_type_node
2120                          : unsigned_accum_type_node;
2121       if (mode == TYPE_MODE (unsigned_long_accum_type_node))
2122         return unsignedp ? sat_unsigned_long_accum_type_node
2123                          : unsigned_long_accum_type_node;
2124       if (mode == TYPE_MODE (unsigned_long_long_accum_type_node))
2125         return unsignedp ? sat_unsigned_long_long_accum_type_node
2126                          : unsigned_long_long_accum_type_node;
2127
2128       if (mode == QQmode)
2129         return unsignedp ? sat_qq_type_node : qq_type_node;
2130       if (mode == HQmode)
2131         return unsignedp ? sat_hq_type_node : hq_type_node;
2132       if (mode == SQmode)
2133         return unsignedp ? sat_sq_type_node : sq_type_node;
2134       if (mode == DQmode)
2135         return unsignedp ? sat_dq_type_node : dq_type_node;
2136       if (mode == TQmode)
2137         return unsignedp ? sat_tq_type_node : tq_type_node;
2138
2139       if (mode == UQQmode)
2140         return unsignedp ? sat_uqq_type_node : uqq_type_node;
2141       if (mode == UHQmode)
2142         return unsignedp ? sat_uhq_type_node : uhq_type_node;
2143       if (mode == USQmode)
2144         return unsignedp ? sat_usq_type_node : usq_type_node;
2145       if (mode == UDQmode)
2146         return unsignedp ? sat_udq_type_node : udq_type_node;
2147       if (mode == UTQmode)
2148         return unsignedp ? sat_utq_type_node : utq_type_node;
2149
2150       if (mode == HAmode)
2151         return unsignedp ? sat_ha_type_node : ha_type_node;
2152       if (mode == SAmode)
2153         return unsignedp ? sat_sa_type_node : sa_type_node;
2154       if (mode == DAmode)
2155         return unsignedp ? sat_da_type_node : da_type_node;
2156       if (mode == TAmode)
2157         return unsignedp ? sat_ta_type_node : ta_type_node;
2158
2159       if (mode == UHAmode)
2160         return unsignedp ? sat_uha_type_node : uha_type_node;
2161       if (mode == USAmode)
2162         return unsignedp ? sat_usa_type_node : usa_type_node;
2163       if (mode == UDAmode)
2164         return unsignedp ? sat_uda_type_node : uda_type_node;
2165       if (mode == UTAmode)
2166         return unsignedp ? sat_uta_type_node : uta_type_node;
2167     }
2168
2169   for (t = registered_builtin_types; t; t = TREE_CHAIN (t))
2170     if (TYPE_MODE (TREE_VALUE (t)) == mode)
2171       return TREE_VALUE (t);
2172
2173   return 0;
2174 }
2175
2176 tree
2177 c_common_unsigned_type (tree type)
2178 {
2179   return c_common_signed_or_unsigned_type (1, type);
2180 }
2181
2182 /* Return a signed type the same as TYPE in other respects.  */
2183
2184 tree
2185 c_common_signed_type (tree type)
2186 {
2187   return c_common_signed_or_unsigned_type (0, type);
2188 }
2189
2190 /* Return a type the same as TYPE except unsigned or
2191    signed according to UNSIGNEDP.  */
2192
2193 tree
2194 c_common_signed_or_unsigned_type (int unsignedp, tree type)
2195 {
2196   tree type1;
2197
2198   /* This block of code emulates the behavior of the old
2199      c_common_unsigned_type. In particular, it returns
2200      long_unsigned_type_node if passed a long, even when a int would
2201      have the same size. This is necessary for warnings to work
2202      correctly in archs where sizeof(int) == sizeof(long) */
2203
2204   type1 = TYPE_MAIN_VARIANT (type);
2205   if (type1 == signed_char_type_node || type1 == char_type_node || type1 == unsigned_char_type_node)
2206     return unsignedp ? unsigned_char_type_node : signed_char_type_node;
2207   if (type1 == integer_type_node || type1 == unsigned_type_node)
2208     return unsignedp ? unsigned_type_node : integer_type_node;
2209   if (type1 == short_integer_type_node || type1 == short_unsigned_type_node)
2210     return unsignedp ? short_unsigned_type_node : short_integer_type_node;
2211   if (type1 == long_integer_type_node || type1 == long_unsigned_type_node)
2212     return unsignedp ? long_unsigned_type_node : long_integer_type_node;
2213   if (type1 == long_long_integer_type_node || type1 == long_long_unsigned_type_node)
2214     return unsignedp ? long_long_unsigned_type_node : long_long_integer_type_node;
2215   if (type1 == widest_integer_literal_type_node || type1 == widest_unsigned_literal_type_node)
2216     return unsignedp ? widest_unsigned_literal_type_node : widest_integer_literal_type_node;
2217 #if HOST_BITS_PER_WIDE_INT >= 64
2218   if (type1 == intTI_type_node || type1 == unsigned_intTI_type_node)
2219     return unsignedp ? unsigned_intTI_type_node : intTI_type_node;
2220 #endif
2221   if (type1 == intDI_type_node || type1 == unsigned_intDI_type_node)
2222     return unsignedp ? unsigned_intDI_type_node : intDI_type_node;
2223   if (type1 == intSI_type_node || type1 == unsigned_intSI_type_node)
2224     return unsignedp ? unsigned_intSI_type_node : intSI_type_node;
2225   if (type1 == intHI_type_node || type1 == unsigned_intHI_type_node)
2226     return unsignedp ? unsigned_intHI_type_node : intHI_type_node;
2227   if (type1 == intQI_type_node || type1 == unsigned_intQI_type_node)
2228     return unsignedp ? unsigned_intQI_type_node : intQI_type_node;
2229
2230 #define C_COMMON_FIXED_TYPES(SAT,NAME) \
2231   if (type1 == SAT ## short_ ## NAME ## _type_node \
2232       || type1 == SAT ## unsigned_short_ ## NAME ## _type_node) \
2233     return unsignedp ? SAT ## unsigned_short_ ## NAME ## _type_node \
2234                      : SAT ## short_ ## NAME ## _type_node; \
2235   if (type1 == SAT ## NAME ## _type_node \
2236       || type1 == SAT ## unsigned_ ## NAME ## _type_node) \
2237     return unsignedp ? SAT ## unsigned_ ## NAME ## _type_node \
2238                      : SAT ## NAME ## _type_node; \
2239   if (type1 == SAT ## long_ ## NAME ## _type_node \
2240       || type1 == SAT ## unsigned_long_ ## NAME ## _type_node) \
2241     return unsignedp ? SAT ## unsigned_long_ ## NAME ## _type_node \
2242                      : SAT ## long_ ## NAME ## _type_node; \
2243   if (type1 == SAT ## long_long_ ## NAME ## _type_node \
2244       || type1 == SAT ## unsigned_long_long_ ## NAME ## _type_node) \
2245     return unsignedp ? SAT ## unsigned_long_long_ ## NAME ## _type_node \
2246                      : SAT ## long_long_ ## NAME ## _type_node;
2247
2248 #define C_COMMON_FIXED_MODE_TYPES(SAT,NAME) \
2249   if (type1 == SAT ## NAME ## _type_node \
2250       || type1 == SAT ## u ## NAME ## _type_node) \
2251     return unsignedp ? SAT ## u ## NAME ## _type_node \
2252                      : SAT ## NAME ## _type_node;
2253
2254   C_COMMON_FIXED_TYPES (, fract);
2255   C_COMMON_FIXED_TYPES (sat_, fract);
2256   C_COMMON_FIXED_TYPES (, accum);
2257   C_COMMON_FIXED_TYPES (sat_, accum);
2258
2259   C_COMMON_FIXED_MODE_TYPES (, qq);
2260   C_COMMON_FIXED_MODE_TYPES (, hq);
2261   C_COMMON_FIXED_MODE_TYPES (, sq);
2262   C_COMMON_FIXED_MODE_TYPES (, dq);
2263   C_COMMON_FIXED_MODE_TYPES (, tq);
2264   C_COMMON_FIXED_MODE_TYPES (sat_, qq);
2265   C_COMMON_FIXED_MODE_TYPES (sat_, hq);
2266   C_COMMON_FIXED_MODE_TYPES (sat_, sq);
2267   C_COMMON_FIXED_MODE_TYPES (sat_, dq);
2268   C_COMMON_FIXED_MODE_TYPES (sat_, tq);
2269   C_COMMON_FIXED_MODE_TYPES (, ha);
2270   C_COMMON_FIXED_MODE_TYPES (, sa);
2271   C_COMMON_FIXED_MODE_TYPES (, da);
2272   C_COMMON_FIXED_MODE_TYPES (, ta);
2273   C_COMMON_FIXED_MODE_TYPES (sat_, ha);
2274   C_COMMON_FIXED_MODE_TYPES (sat_, sa);
2275   C_COMMON_FIXED_MODE_TYPES (sat_, da);
2276   C_COMMON_FIXED_MODE_TYPES (sat_, ta);
2277
2278   /* For ENUMERAL_TYPEs in C++, must check the mode of the types, not
2279      the precision; they have precision set to match their range, but
2280      may use a wider mode to match an ABI.  If we change modes, we may
2281      wind up with bad conversions.  For INTEGER_TYPEs in C, must check
2282      the precision as well, so as to yield correct results for
2283      bit-field types.  C++ does not have these separate bit-field
2284      types, and producing a signed or unsigned variant of an
2285      ENUMERAL_TYPE may cause other problems as well.  */
2286
2287   if (!INTEGRAL_TYPE_P (type)
2288       || TYPE_UNSIGNED (type) == unsignedp)
2289     return type;
2290
2291 #define TYPE_OK(node)                                                       \
2292   (TYPE_MODE (type) == TYPE_MODE (node)                                     \
2293    && (c_dialect_cxx () || TYPE_PRECISION (type) == TYPE_PRECISION (node)))
2294   if (TYPE_OK (signed_char_type_node))
2295     return unsignedp ? unsigned_char_type_node : signed_char_type_node;
2296   if (TYPE_OK (integer_type_node))
2297     return unsignedp ? unsigned_type_node : integer_type_node;
2298   if (TYPE_OK (short_integer_type_node))
2299     return unsignedp ? short_unsigned_type_node : short_integer_type_node;
2300   if (TYPE_OK (long_integer_type_node))
2301     return unsignedp ? long_unsigned_type_node : long_integer_type_node;
2302   if (TYPE_OK (long_long_integer_type_node))
2303     return (unsignedp ? long_long_unsigned_type_node
2304             : long_long_integer_type_node);
2305   if (TYPE_OK (widest_integer_literal_type_node))
2306     return (unsignedp ? widest_unsigned_literal_type_node
2307             : widest_integer_literal_type_node);
2308
2309 #if HOST_BITS_PER_WIDE_INT >= 64
2310   if (TYPE_OK (intTI_type_node))
2311     return unsignedp ? unsigned_intTI_type_node : intTI_type_node;
2312 #endif
2313   if (TYPE_OK (intDI_type_node))
2314     return unsignedp ? unsigned_intDI_type_node : intDI_type_node;
2315   if (TYPE_OK (intSI_type_node))
2316     return unsignedp ? unsigned_intSI_type_node : intSI_type_node;
2317   if (TYPE_OK (intHI_type_node))
2318     return unsignedp ? unsigned_intHI_type_node : intHI_type_node;
2319   if (TYPE_OK (intQI_type_node))
2320     return unsignedp ? unsigned_intQI_type_node : intQI_type_node;
2321 #undef TYPE_OK
2322
2323   if (c_dialect_cxx ())
2324     return type;
2325   else
2326     return build_nonstandard_integer_type (TYPE_PRECISION (type), unsignedp);
2327 }
2328
2329 /* Build a bit-field integer type for the given WIDTH and UNSIGNEDP.  */
2330
2331 tree
2332 c_build_bitfield_integer_type (unsigned HOST_WIDE_INT width, int unsignedp)
2333 {
2334   /* Extended integer types of the same width as a standard type have
2335      lesser rank, so those of the same width as int promote to int or
2336      unsigned int and are valid for printf formats expecting int or
2337      unsigned int.  To avoid such special cases, avoid creating
2338      extended integer types for bit-fields if a standard integer type
2339      is available.  */
2340   if (width == TYPE_PRECISION (integer_type_node))
2341     return unsignedp ? unsigned_type_node : integer_type_node;
2342   if (width == TYPE_PRECISION (signed_char_type_node))
2343     return unsignedp ? unsigned_char_type_node : signed_char_type_node;
2344   if (width == TYPE_PRECISION (short_integer_type_node))
2345     return unsignedp ? short_unsigned_type_node : short_integer_type_node;
2346   if (width == TYPE_PRECISION (long_integer_type_node))
2347     return unsignedp ? long_unsigned_type_node : long_integer_type_node;
2348   if (width == TYPE_PRECISION (long_long_integer_type_node))
2349     return (unsignedp ? long_long_unsigned_type_node
2350             : long_long_integer_type_node);
2351   return build_nonstandard_integer_type (width, unsignedp);
2352 }
2353
2354 /* The C version of the register_builtin_type langhook.  */
2355
2356 void
2357 c_register_builtin_type (tree type, const char* name)
2358 {
2359   tree decl;
2360
2361   decl = build_decl (TYPE_DECL, get_identifier (name), type);
2362   DECL_ARTIFICIAL (decl) = 1;
2363   if (!TYPE_NAME (type))
2364     TYPE_NAME (type) = decl;
2365   pushdecl (decl);
2366
2367   registered_builtin_types = tree_cons (0, type, registered_builtin_types);
2368 }
2369
2370 \f
2371 /* Return the minimum number of bits needed to represent VALUE in a
2372    signed or unsigned type, UNSIGNEDP says which.  */
2373
2374 unsigned int
2375 min_precision (tree value, int unsignedp)
2376 {
2377   int log;
2378
2379   /* If the value is negative, compute its negative minus 1.  The latter
2380      adjustment is because the absolute value of the largest negative value
2381      is one larger than the largest positive value.  This is equivalent to
2382      a bit-wise negation, so use that operation instead.  */
2383
2384   if (tree_int_cst_sgn (value) < 0)
2385     value = fold_build1 (BIT_NOT_EXPR, TREE_TYPE (value), value);
2386
2387   /* Return the number of bits needed, taking into account the fact
2388      that we need one more bit for a signed than unsigned type.  */
2389
2390   if (integer_zerop (value))
2391     log = 0;
2392   else
2393     log = tree_floor_log2 (value);
2394
2395   return log + 1 + !unsignedp;
2396 }
2397 \f
2398 /* Print an error message for invalid operands to arith operation
2399    CODE with TYPE0 for operand 0, and TYPE1 for operand 1.  */
2400
2401 void
2402 binary_op_error (enum tree_code code, tree type0, tree type1)
2403 {
2404   const char *opname;
2405
2406   switch (code)
2407     {
2408     case PLUS_EXPR:
2409       opname = "+"; break;
2410     case MINUS_EXPR:
2411       opname = "-"; break;
2412     case MULT_EXPR:
2413       opname = "*"; break;
2414     case MAX_EXPR:
2415       opname = "max"; break;
2416     case MIN_EXPR:
2417       opname = "min"; break;
2418     case EQ_EXPR:
2419       opname = "=="; break;
2420     case NE_EXPR:
2421       opname = "!="; break;
2422     case LE_EXPR:
2423       opname = "<="; break;
2424     case GE_EXPR:
2425       opname = ">="; break;
2426     case LT_EXPR:
2427       opname = "<"; break;
2428     case GT_EXPR:
2429       opname = ">"; break;
2430     case LSHIFT_EXPR:
2431       opname = "<<"; break;
2432     case RSHIFT_EXPR:
2433       opname = ">>"; break;
2434     case TRUNC_MOD_EXPR:
2435     case FLOOR_MOD_EXPR:
2436       opname = "%"; break;
2437     case TRUNC_DIV_EXPR:
2438     case FLOOR_DIV_EXPR:
2439       opname = "/"; break;
2440     case BIT_AND_EXPR:
2441       opname = "&"; break;
2442     case BIT_IOR_EXPR:
2443       opname = "|"; break;
2444     case TRUTH_ANDIF_EXPR:
2445       opname = "&&"; break;
2446     case TRUTH_ORIF_EXPR:
2447       opname = "||"; break;
2448     case BIT_XOR_EXPR:
2449       opname = "^"; break;
2450     default:
2451       gcc_unreachable ();
2452     }
2453   error ("invalid operands to binary %s (have %qT and %qT)", opname,
2454          type0, type1);
2455 }
2456 \f
2457 /* Subroutine of build_binary_op, used for comparison operations.
2458    See if the operands have both been converted from subword integer types
2459    and, if so, perhaps change them both back to their original type.
2460    This function is also responsible for converting the two operands
2461    to the proper common type for comparison.
2462
2463    The arguments of this function are all pointers to local variables
2464    of build_binary_op: OP0_PTR is &OP0, OP1_PTR is &OP1,
2465    RESTYPE_PTR is &RESULT_TYPE and RESCODE_PTR is &RESULTCODE.
2466
2467    If this function returns nonzero, it means that the comparison has
2468    a constant value.  What this function returns is an expression for
2469    that value.  */
2470
2471 tree
2472 shorten_compare (tree *op0_ptr, tree *op1_ptr, tree *restype_ptr,
2473                  enum tree_code *rescode_ptr)
2474 {
2475   tree type;
2476   tree op0 = *op0_ptr;
2477   tree op1 = *op1_ptr;
2478   int unsignedp0, unsignedp1;
2479   int real1, real2;
2480   tree primop0, primop1;
2481   enum tree_code code = *rescode_ptr;
2482
2483   /* Throw away any conversions to wider types
2484      already present in the operands.  */
2485
2486   primop0 = get_narrower (op0, &unsignedp0);
2487   primop1 = get_narrower (op1, &unsignedp1);
2488
2489   /* Handle the case that OP0 does not *contain* a conversion
2490      but it *requires* conversion to FINAL_TYPE.  */
2491
2492   if (op0 == primop0 && TREE_TYPE (op0) != *restype_ptr)
2493     unsignedp0 = TYPE_UNSIGNED (TREE_TYPE (op0));
2494   if (op1 == primop1 && TREE_TYPE (op1) != *restype_ptr)
2495     unsignedp1 = TYPE_UNSIGNED (TREE_TYPE (op1));
2496
2497   /* If one of the operands must be floated, we cannot optimize.  */
2498   real1 = TREE_CODE (TREE_TYPE (primop0)) == REAL_TYPE;
2499   real2 = TREE_CODE (TREE_TYPE (primop1)) == REAL_TYPE;
2500
2501   /* If first arg is constant, swap the args (changing operation
2502      so value is preserved), for canonicalization.  Don't do this if
2503      the second arg is 0.  */
2504
2505   if (TREE_CONSTANT (primop0)
2506       && !integer_zerop (primop1) && !real_zerop (primop1)
2507       && !fixed_zerop (primop1))
2508     {
2509       tree tem = primop0;
2510       int temi = unsignedp0;
2511       primop0 = primop1;
2512       primop1 = tem;
2513       tem = op0;
2514       op0 = op1;
2515       op1 = tem;
2516       *op0_ptr = op0;
2517       *op1_ptr = op1;
2518       unsignedp0 = unsignedp1;
2519       unsignedp1 = temi;
2520       temi = real1;
2521       real1 = real2;
2522       real2 = temi;
2523
2524       switch (code)
2525         {
2526         case LT_EXPR:
2527           code = GT_EXPR;
2528           break;
2529         case GT_EXPR:
2530           code = LT_EXPR;
2531           break;
2532         case LE_EXPR:
2533           code = GE_EXPR;
2534           break;
2535         case GE_EXPR:
2536           code = LE_EXPR;
2537           break;
2538         default:
2539           break;
2540         }
2541       *rescode_ptr = code;
2542     }
2543
2544   /* If comparing an integer against a constant more bits wide,
2545      maybe we can deduce a value of 1 or 0 independent of the data.
2546      Or else truncate the constant now
2547      rather than extend the variable at run time.
2548
2549      This is only interesting if the constant is the wider arg.
2550      Also, it is not safe if the constant is unsigned and the
2551      variable arg is signed, since in this case the variable
2552      would be sign-extended and then regarded as unsigned.
2553      Our technique fails in this case because the lowest/highest
2554      possible unsigned results don't follow naturally from the
2555      lowest/highest possible values of the variable operand.
2556      For just EQ_EXPR and NE_EXPR there is another technique that
2557      could be used: see if the constant can be faithfully represented
2558      in the other operand's type, by truncating it and reextending it
2559      and see if that preserves the constant's value.  */
2560
2561   if (!real1 && !real2
2562       && TREE_CODE (TREE_TYPE (primop0)) != FIXED_POINT_TYPE
2563       && TREE_CODE (primop1) == INTEGER_CST
2564       && TYPE_PRECISION (TREE_TYPE (primop0)) < TYPE_PRECISION (*restype_ptr))
2565     {
2566       int min_gt, max_gt, min_lt, max_lt;
2567       tree maxval, minval;
2568       /* 1 if comparison is nominally unsigned.  */
2569       int unsignedp = TYPE_UNSIGNED (*restype_ptr);
2570       tree val;
2571
2572       type = c_common_signed_or_unsigned_type (unsignedp0,
2573                                                TREE_TYPE (primop0));
2574
2575       maxval = TYPE_MAX_VALUE (type);
2576       minval = TYPE_MIN_VALUE (type);
2577
2578       if (unsignedp && !unsignedp0)
2579         *restype_ptr = c_common_signed_type (*restype_ptr);
2580
2581       if (TREE_TYPE (primop1) != *restype_ptr)
2582         {
2583           /* Convert primop1 to target type, but do not introduce
2584              additional overflow.  We know primop1 is an int_cst.  */
2585           primop1 = force_fit_type_double (*restype_ptr,
2586                                            TREE_INT_CST_LOW (primop1),
2587                                            TREE_INT_CST_HIGH (primop1), 0,
2588                                            TREE_OVERFLOW (primop1));
2589         }
2590       if (type != *restype_ptr)
2591         {
2592           minval = convert (*restype_ptr, minval);
2593           maxval = convert (*restype_ptr, maxval);
2594         }
2595
2596       if (unsignedp && unsignedp0)
2597         {
2598           min_gt = INT_CST_LT_UNSIGNED (primop1, minval);
2599           max_gt = INT_CST_LT_UNSIGNED (primop1, maxval);
2600           min_lt = INT_CST_LT_UNSIGNED (minval, primop1);
2601           max_lt = INT_CST_LT_UNSIGNED (maxval, primop1);
2602         }
2603       else
2604         {
2605           min_gt = INT_CST_LT (primop1, minval);
2606           max_gt = INT_CST_LT (primop1, maxval);
2607           min_lt = INT_CST_LT (minval, primop1);
2608           max_lt = INT_CST_LT (maxval, primop1);
2609         }
2610
2611       val = 0;
2612       /* This used to be a switch, but Genix compiler can't handle that.  */
2613       if (code == NE_EXPR)
2614         {
2615           if (max_lt || min_gt)
2616             val = truthvalue_true_node;
2617         }
2618       else if (code == EQ_EXPR)
2619         {
2620           if (max_lt || min_gt)
2621             val = truthvalue_false_node;
2622         }
2623       else if (code == LT_EXPR)
2624         {
2625           if (max_lt)
2626             val = truthvalue_true_node;
2627           if (!min_lt)
2628             val = truthvalue_false_node;
2629         }
2630       else if (code == GT_EXPR)
2631         {
2632           if (min_gt)
2633             val = truthvalue_true_node;
2634           if (!max_gt)
2635             val = truthvalue_false_node;
2636         }
2637       else if (code == LE_EXPR)
2638         {
2639           if (!max_gt)
2640             val = truthvalue_true_node;
2641           if (min_gt)
2642             val = truthvalue_false_node;
2643         }
2644       else if (code == GE_EXPR)
2645         {
2646           if (!min_lt)
2647             val = truthvalue_true_node;
2648           if (max_lt)
2649             val = truthvalue_false_node;
2650         }
2651
2652       /* If primop0 was sign-extended and unsigned comparison specd,
2653          we did a signed comparison above using the signed type bounds.
2654          But the comparison we output must be unsigned.
2655
2656          Also, for inequalities, VAL is no good; but if the signed
2657          comparison had *any* fixed result, it follows that the
2658          unsigned comparison just tests the sign in reverse
2659          (positive values are LE, negative ones GE).
2660          So we can generate an unsigned comparison
2661          against an extreme value of the signed type.  */
2662
2663       if (unsignedp && !unsignedp0)
2664         {
2665           if (val != 0)
2666             switch (code)
2667               {
2668               case LT_EXPR:
2669               case GE_EXPR:
2670                 primop1 = TYPE_MIN_VALUE (type);
2671                 val = 0;
2672                 break;
2673
2674               case LE_EXPR:
2675               case GT_EXPR:
2676                 primop1 = TYPE_MAX_VALUE (type);
2677                 val = 0;
2678                 break;
2679
2680               default:
2681                 break;
2682               }
2683           type = c_common_unsigned_type (type);
2684         }
2685
2686       if (TREE_CODE (primop0) != INTEGER_CST)
2687         {
2688           if (val == truthvalue_false_node)
2689             warning (OPT_Wtype_limits, "comparison is always false due to limited range of data type");
2690           if (val == truthvalue_true_node)
2691             warning (OPT_Wtype_limits, "comparison is always true due to limited range of data type");
2692         }
2693
2694       if (val != 0)
2695         {
2696           /* Don't forget to evaluate PRIMOP0 if it has side effects.  */
2697           if (TREE_SIDE_EFFECTS (primop0))
2698             return build2 (COMPOUND_EXPR, TREE_TYPE (val), primop0, val);
2699           return val;
2700         }
2701
2702       /* Value is not predetermined, but do the comparison
2703          in the type of the operand that is not constant.
2704          TYPE is already properly set.  */
2705     }
2706
2707   /* If either arg is decimal float and the other is float, find the
2708      proper common type to use for comparison.  */
2709   else if (real1 && real2
2710            && (DECIMAL_FLOAT_MODE_P (TYPE_MODE (TREE_TYPE (primop0)))
2711                || DECIMAL_FLOAT_MODE_P (TYPE_MODE (TREE_TYPE (primop1)))))
2712     type = common_type (TREE_TYPE (primop0), TREE_TYPE (primop1));
2713
2714   else if (real1 && real2
2715            && (TYPE_PRECISION (TREE_TYPE (primop0))
2716                == TYPE_PRECISION (TREE_TYPE (primop1))))
2717     type = TREE_TYPE (primop0);
2718
2719   /* If args' natural types are both narrower than nominal type
2720      and both extend in the same manner, compare them
2721      in the type of the wider arg.
2722      Otherwise must actually extend both to the nominal
2723      common type lest different ways of extending
2724      alter the result.
2725      (eg, (short)-1 == (unsigned short)-1  should be 0.)  */
2726
2727   else if (unsignedp0 == unsignedp1 && real1 == real2
2728            && TYPE_PRECISION (TREE_TYPE (primop0)) < TYPE_PRECISION (*restype_ptr)
2729            && TYPE_PRECISION (TREE_TYPE (primop1)) < TYPE_PRECISION (*restype_ptr))
2730     {
2731       type = common_type (TREE_TYPE (primop0), TREE_TYPE (primop1));
2732       type = c_common_signed_or_unsigned_type (unsignedp0
2733                                                || TYPE_UNSIGNED (*restype_ptr),
2734                                                type);
2735       /* Make sure shorter operand is extended the right way
2736          to match the longer operand.  */
2737       primop0
2738         = convert (c_common_signed_or_unsigned_type (unsignedp0,
2739                                                      TREE_TYPE (primop0)),
2740                    primop0);
2741       primop1
2742         = convert (c_common_signed_or_unsigned_type (unsignedp1,
2743                                                      TREE_TYPE (primop1)),
2744                    primop1);
2745     }
2746   else
2747     {
2748       /* Here we must do the comparison on the nominal type
2749          using the args exactly as we received them.  */
2750       type = *restype_ptr;
2751       primop0 = op0;
2752       primop1 = op1;
2753
2754       if (!real1 && !real2 && integer_zerop (primop1)
2755           && TYPE_UNSIGNED (*restype_ptr))
2756         {
2757           tree value = 0;
2758           switch (code)
2759             {
2760             case GE_EXPR:
2761               /* All unsigned values are >= 0, so we warn.  However,
2762                  if OP0 is a constant that is >= 0, the signedness of
2763                  the comparison isn't an issue, so suppress the
2764                  warning.  */
2765               if (warn_type_limits && !in_system_header
2766                   && !(TREE_CODE (primop0) == INTEGER_CST
2767                        && !TREE_OVERFLOW (convert (c_common_signed_type (type),
2768                                                    primop0))))
2769                 warning (OPT_Wtype_limits,
2770                          "comparison of unsigned expression >= 0 is always true");
2771               value = truthvalue_true_node;
2772               break;
2773
2774             case LT_EXPR:
2775               if (warn_type_limits && !in_system_header
2776                   && !(TREE_CODE (primop0) == INTEGER_CST
2777                        && !TREE_OVERFLOW (convert (c_common_signed_type (type),
2778                                                    primop0))))
2779                 warning (OPT_Wtype_limits,
2780                          "comparison of unsigned expression < 0 is always false");
2781               value = truthvalue_false_node;
2782               break;
2783
2784             default:
2785               break;
2786             }
2787
2788           if (value != 0)
2789             {
2790               /* Don't forget to evaluate PRIMOP0 if it has side effects.  */
2791               if (TREE_SIDE_EFFECTS (primop0))
2792                 return build2 (COMPOUND_EXPR, TREE_TYPE (value),
2793                                primop0, value);
2794               return value;
2795             }
2796         }
2797     }
2798
2799   *op0_ptr = convert (type, primop0);
2800   *op1_ptr = convert (type, primop1);
2801
2802   *restype_ptr = truthvalue_type_node;
2803
2804   return 0;
2805 }
2806 \f
2807 /* Return a tree for the sum or difference (RESULTCODE says which)
2808    of pointer PTROP and integer INTOP.  */
2809
2810 tree
2811 pointer_int_sum (enum tree_code resultcode, tree ptrop, tree intop)
2812 {
2813   tree size_exp, ret;
2814
2815   /* The result is a pointer of the same type that is being added.  */
2816   tree result_type = TREE_TYPE (ptrop);
2817
2818   if (TREE_CODE (TREE_TYPE (result_type)) == VOID_TYPE)
2819     {
2820       if (pedantic || warn_pointer_arith)
2821         pedwarn ("pointer of type %<void *%> used in arithmetic");
2822       size_exp = integer_one_node;
2823     }
2824   else if (TREE_CODE (TREE_TYPE (result_type)) == FUNCTION_TYPE)
2825     {
2826       if (pedantic || warn_pointer_arith)
2827         pedwarn ("pointer to a function used in arithmetic");
2828       size_exp = integer_one_node;
2829     }
2830   else if (TREE_CODE (TREE_TYPE (result_type)) == METHOD_TYPE)
2831     {
2832       if (pedantic || warn_pointer_arith)
2833         pedwarn ("pointer to member function used in arithmetic");
2834       size_exp = integer_one_node;
2835     }
2836   else
2837     size_exp = size_in_bytes (TREE_TYPE (result_type));
2838
2839   /* We are manipulating pointer values, so we don't need to warn
2840      about relying on undefined signed overflow.  We disable the
2841      warning here because we use integer types so fold won't know that
2842      they are really pointers.  */
2843   fold_defer_overflow_warnings ();
2844
2845   /* If what we are about to multiply by the size of the elements
2846      contains a constant term, apply distributive law
2847      and multiply that constant term separately.
2848      This helps produce common subexpressions.  */
2849   if ((TREE_CODE (intop) == PLUS_EXPR || TREE_CODE (intop) == MINUS_EXPR)
2850       && !TREE_CONSTANT (intop)
2851       && TREE_CONSTANT (TREE_OPERAND (intop, 1))
2852       && TREE_CONSTANT (size_exp)
2853       /* If the constant comes from pointer subtraction,
2854          skip this optimization--it would cause an error.  */
2855       && TREE_CODE (TREE_TYPE (TREE_OPERAND (intop, 0))) == INTEGER_TYPE
2856       /* If the constant is unsigned, and smaller than the pointer size,
2857          then we must skip this optimization.  This is because it could cause
2858          an overflow error if the constant is negative but INTOP is not.  */
2859       && (!TYPE_UNSIGNED (TREE_TYPE (intop))
2860           || (TYPE_PRECISION (TREE_TYPE (intop))
2861               == TYPE_PRECISION (TREE_TYPE (ptrop)))))
2862     {
2863       enum tree_code subcode = resultcode;
2864       tree int_type = TREE_TYPE (intop);
2865       if (TREE_CODE (intop) == MINUS_EXPR)
2866         subcode = (subcode == PLUS_EXPR ? MINUS_EXPR : PLUS_EXPR);
2867       /* Convert both subexpression types to the type of intop,
2868          because weird cases involving pointer arithmetic
2869          can result in a sum or difference with different type args.  */
2870       ptrop = build_binary_op (subcode, ptrop,
2871                                convert (int_type, TREE_OPERAND (intop, 1)), 1);
2872       intop = convert (int_type, TREE_OPERAND (intop, 0));
2873     }
2874
2875   /* Convert the integer argument to a type the same size as sizetype
2876      so the multiply won't overflow spuriously.  */
2877   if (TYPE_PRECISION (TREE_TYPE (intop)) != TYPE_PRECISION (sizetype)
2878       || TYPE_UNSIGNED (TREE_TYPE (intop)) != TYPE_UNSIGNED (sizetype))
2879     intop = convert (c_common_type_for_size (TYPE_PRECISION (sizetype),
2880                                              TYPE_UNSIGNED (sizetype)), intop);
2881
2882   /* Replace the integer argument with a suitable product by the object size.
2883      Do this multiplication as signed, then convert to the appropriate
2884      type for the pointer operation.  */
2885   intop = convert (sizetype,
2886                    build_binary_op (MULT_EXPR, intop,
2887                                     convert (TREE_TYPE (intop), size_exp), 1));
2888
2889   /* Create the sum or difference.  */
2890   if (resultcode == MINUS_EXPR)
2891     intop = fold_build1 (NEGATE_EXPR, sizetype, intop);
2892
2893   ret = fold_build2 (POINTER_PLUS_EXPR, result_type, ptrop, intop);
2894
2895   fold_undefer_and_ignore_overflow_warnings ();
2896
2897   return ret;
2898 }
2899 \f
2900 /* Return whether EXPR is a declaration whose address can never be
2901    NULL.  */
2902
2903 bool
2904 decl_with_nonnull_addr_p (const_tree expr)
2905 {
2906   return (DECL_P (expr)
2907           && (TREE_CODE (expr) == PARM_DECL
2908               || TREE_CODE (expr) == LABEL_DECL
2909               || !DECL_WEAK (expr)));
2910 }
2911
2912 /* Prepare expr to be an argument of a TRUTH_NOT_EXPR,
2913    or for an `if' or `while' statement or ?..: exp.  It should already
2914    have been validated to be of suitable type; otherwise, a bad
2915    diagnostic may result.
2916
2917    This preparation consists of taking the ordinary
2918    representation of an expression expr and producing a valid tree
2919    boolean expression describing whether expr is nonzero.  We could
2920    simply always do build_binary_op (NE_EXPR, expr, truthvalue_false_node, 1),
2921    but we optimize comparisons, &&, ||, and !.
2922
2923    The resulting type should always be `truthvalue_type_node'.  */
2924
2925 tree
2926 c_common_truthvalue_conversion (tree expr)
2927 {
2928   switch (TREE_CODE (expr))
2929     {
2930     case EQ_EXPR:   case NE_EXPR:   case UNEQ_EXPR: case LTGT_EXPR:
2931     case LE_EXPR:   case GE_EXPR:   case LT_EXPR:   case GT_EXPR:
2932     case UNLE_EXPR: case UNGE_EXPR: case UNLT_EXPR: case UNGT_EXPR:
2933     case ORDERED_EXPR: case UNORDERED_EXPR:
2934       if (TREE_TYPE (expr) == truthvalue_type_node)
2935         return expr;
2936       return build2 (TREE_CODE (expr), truthvalue_type_node,
2937                      TREE_OPERAND (expr, 0), TREE_OPERAND (expr, 1));
2938
2939     case TRUTH_ANDIF_EXPR:
2940     case TRUTH_ORIF_EXPR:
2941     case TRUTH_AND_EXPR:
2942     case TRUTH_OR_EXPR:
2943     case TRUTH_XOR_EXPR:
2944       if (TREE_TYPE (expr) == truthvalue_type_node)
2945         return expr;
2946       return build2 (TREE_CODE (expr), truthvalue_type_node,
2947                  c_common_truthvalue_conversion (TREE_OPERAND (expr, 0)),
2948                  c_common_truthvalue_conversion (TREE_OPERAND (expr, 1)));
2949
2950     case TRUTH_NOT_EXPR:
2951       if (TREE_TYPE (expr) == truthvalue_type_node)
2952         return expr;
2953       return build1 (TREE_CODE (expr), truthvalue_type_node,
2954                  c_common_truthvalue_conversion (TREE_OPERAND (expr, 0)));
2955
2956     case ERROR_MARK:
2957       return expr;
2958
2959     case INTEGER_CST:
2960       return integer_zerop (expr) ? truthvalue_false_node
2961                                   : truthvalue_true_node;
2962
2963     case REAL_CST:
2964       return real_compare (NE_EXPR, &TREE_REAL_CST (expr), &dconst0)
2965              ? truthvalue_true_node
2966              : truthvalue_false_node;
2967
2968     case FIXED_CST:
2969       return fixed_compare (NE_EXPR, &TREE_FIXED_CST (expr),
2970                             &FCONST0 (TYPE_MODE (TREE_TYPE (expr))))
2971              ? truthvalue_true_node
2972              : truthvalue_false_node;
2973
2974     case FUNCTION_DECL:
2975       expr = build_unary_op (ADDR_EXPR, expr, 0);
2976       /* Fall through.  */
2977
2978     case ADDR_EXPR:
2979       {
2980         tree inner = TREE_OPERAND (expr, 0);
2981         if (decl_with_nonnull_addr_p (inner))
2982           {
2983             /* Common Ada/Pascal programmer's mistake.  */
2984             warning (OPT_Waddress,
2985                      "the address of %qD will always evaluate as %<true%>",
2986                      inner);
2987             return truthvalue_true_node;
2988           }
2989
2990         /* If we still have a decl, it is possible for its address to
2991            be NULL, so we cannot optimize.  */
2992         if (DECL_P (inner))
2993           {
2994             gcc_assert (DECL_WEAK (inner));
2995             break;
2996           }
2997
2998         if (TREE_SIDE_EFFECTS (inner))
2999           return build2 (COMPOUND_EXPR, truthvalue_type_node,
3000                          inner, truthvalue_true_node);
3001         else
3002           return truthvalue_true_node;
3003       }
3004
3005     case COMPLEX_EXPR:
3006       return build_binary_op ((TREE_SIDE_EFFECTS (TREE_OPERAND (expr, 1))
3007                                ? TRUTH_OR_EXPR : TRUTH_ORIF_EXPR),
3008                 c_common_truthvalue_conversion (TREE_OPERAND (expr, 0)),
3009                 c_common_truthvalue_conversion (TREE_OPERAND (expr, 1)),
3010                               0);
3011
3012     case NEGATE_EXPR:
3013     case ABS_EXPR:
3014     case FLOAT_EXPR:
3015       /* These don't change whether an object is nonzero or zero.  */
3016       return c_common_truthvalue_conversion (TREE_OPERAND (expr, 0));
3017
3018     case LROTATE_EXPR:
3019     case RROTATE_EXPR:
3020       /* These don't change whether an object is zero or nonzero, but
3021          we can't ignore them if their second arg has side-effects.  */
3022       if (TREE_SIDE_EFFECTS (TREE_OPERAND (expr, 1)))
3023         return build2 (COMPOUND_EXPR, truthvalue_type_node,
3024                        TREE_OPERAND (expr, 1),
3025                        c_common_truthvalue_conversion (TREE_OPERAND (expr, 0)));
3026       else
3027         return c_common_truthvalue_conversion (TREE_OPERAND (expr, 0));
3028
3029     case COND_EXPR:
3030       /* Distribute the conversion into the arms of a COND_EXPR.  */
3031       return fold_build3 (COND_EXPR, truthvalue_type_node,
3032                 TREE_OPERAND (expr, 0),
3033                 c_common_truthvalue_conversion (TREE_OPERAND (expr, 1)),
3034                 c_common_truthvalue_conversion (TREE_OPERAND (expr, 2)));
3035
3036     case CONVERT_EXPR:
3037     case NOP_EXPR:
3038       /* Don't cancel the effect of a CONVERT_EXPR from a REFERENCE_TYPE,
3039          since that affects how `default_conversion' will behave.  */
3040       if (TREE_CODE (TREE_TYPE (expr)) == REFERENCE_TYPE
3041           || TREE_CODE (TREE_TYPE (TREE_OPERAND (expr, 0))) == REFERENCE_TYPE)
3042         break;
3043       /* If this is widening the argument, we can ignore it.  */
3044       if (TYPE_PRECISION (TREE_TYPE (expr))
3045           >= TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (expr, 0))))
3046         return c_common_truthvalue_conversion (TREE_OPERAND (expr, 0));
3047       break;
3048
3049     case MODIFY_EXPR:
3050       if (!TREE_NO_WARNING (expr)
3051           && warn_parentheses)
3052         {
3053           warning (OPT_Wparentheses,
3054                    "suggest parentheses around assignment used as truth value");
3055           TREE_NO_WARNING (expr) = 1;
3056         }
3057       break;
3058
3059     default:
3060       break;
3061     }
3062
3063   if (TREE_CODE (TREE_TYPE (expr)) == COMPLEX_TYPE)
3064     {
3065       tree t = save_expr (expr);
3066       return (build_binary_op
3067               ((TREE_SIDE_EFFECTS (expr)
3068                 ? TRUTH_OR_EXPR : TRUTH_ORIF_EXPR),
3069         c_common_truthvalue_conversion (build_unary_op (REALPART_EXPR, t, 0)),
3070         c_common_truthvalue_conversion (build_unary_op (IMAGPART_EXPR, t, 0)),
3071                0));
3072     }
3073
3074   if (TREE_CODE (TREE_TYPE (expr)) == FIXED_POINT_TYPE)
3075     {
3076       tree fixed_zero_node = build_fixed (TREE_TYPE (expr),
3077                                           FCONST0 (TYPE_MODE
3078                                                    (TREE_TYPE (expr))));
3079       return build_binary_op (NE_EXPR, expr, fixed_zero_node, 1);
3080     }
3081
3082   return build_binary_op (NE_EXPR, expr, integer_zero_node, 1);
3083 }
3084 \f
3085 static void def_builtin_1  (enum built_in_function fncode,
3086                             const char *name,
3087                             enum built_in_class fnclass,
3088                             tree fntype, tree libtype,
3089                             bool both_p, bool fallback_p, bool nonansi_p,
3090                             tree fnattrs, bool implicit_p);
3091
3092
3093 /* Apply the TYPE_QUALS to the new DECL.  */
3094
3095 void
3096 c_apply_type_quals_to_decl (int type_quals, tree decl)
3097 {
3098   tree type = TREE_TYPE (decl);
3099
3100   if (type == error_mark_node)
3101     return;
3102
3103   if (((type_quals & TYPE_QUAL_CONST)
3104        || (type && TREE_CODE (type) == REFERENCE_TYPE))
3105       /* An object declared 'const' is only readonly after it is
3106          initialized.  We don't have any way of expressing this currently,
3107          so we need to be conservative and unset TREE_READONLY for types
3108          with constructors.  Otherwise aliasing code will ignore stores in
3109          an inline constructor.  */
3110       && !(type && TYPE_NEEDS_CONSTRUCTING (type)))
3111     TREE_READONLY (decl) = 1;
3112   if (type_quals & TYPE_QUAL_VOLATILE)
3113     {
3114       TREE_SIDE_EFFECTS (decl) = 1;
3115       TREE_THIS_VOLATILE (decl) = 1;
3116     }
3117   if (type_quals & TYPE_QUAL_RESTRICT)
3118     {
3119       while (type && TREE_CODE (type) == ARRAY_TYPE)
3120         /* Allow 'restrict' on arrays of pointers.
3121            FIXME currently we just ignore it.  */
3122         type = TREE_TYPE (type);
3123       if (!type
3124           || !POINTER_TYPE_P (type)
3125           || !C_TYPE_OBJECT_OR_INCOMPLETE_P (TREE_TYPE (type)))
3126         error ("invalid use of %<restrict%>");
3127       else if (flag_strict_aliasing && type == TREE_TYPE (decl))
3128         /* Indicate we need to make a unique alias set for this pointer.
3129            We can't do it here because it might be pointing to an
3130            incomplete type.  */
3131         DECL_POINTER_ALIAS_SET (decl) = -2;
3132     }
3133 }
3134
3135 /* Hash function for the problem of multiple type definitions in
3136    different files.  This must hash all types that will compare
3137    equal via comptypes to the same value.  In practice it hashes
3138    on some of the simple stuff and leaves the details to comptypes.  */
3139
3140 static hashval_t
3141 c_type_hash (const void *p)
3142 {
3143   int i = 0;
3144   int shift, size;
3145   const_tree const t = (const_tree) p;
3146   tree t2;
3147   switch (TREE_CODE (t))
3148     {
3149     /* For pointers, hash on pointee type plus some swizzling.  */
3150     case POINTER_TYPE:
3151       return c_type_hash (TREE_TYPE (t)) ^ 0x3003003;
3152     /* Hash on number of elements and total size.  */
3153     case ENUMERAL_TYPE:
3154       shift = 3;
3155       t2 = TYPE_VALUES (t);
3156       break;
3157     case RECORD_TYPE:
3158       shift = 0;
3159       t2 = TYPE_FIELDS (t);
3160       break;
3161     case QUAL_UNION_TYPE:
3162       shift = 1;
3163       t2 = TYPE_FIELDS (t);
3164       break;
3165     case UNION_TYPE:
3166       shift = 2;
3167       t2 = TYPE_FIELDS (t);
3168       break;
3169     default:
3170       gcc_unreachable ();
3171     }
3172   for (; t2; t2 = TREE_CHAIN (t2))
3173     i++;
3174   /* We might have a VLA here.  */
3175   if (TREE_CODE (TYPE_SIZE (t)) != INTEGER_CST)
3176     size = 0;
3177   else
3178     size = TREE_INT_CST_LOW (TYPE_SIZE (t));
3179   return ((size << 24) | (i << shift));
3180 }
3181
3182 static GTY((param_is (union tree_node))) htab_t type_hash_table;
3183
3184 /* Return the typed-based alias set for T, which may be an expression
3185    or a type.  Return -1 if we don't do anything special.  */
3186
3187 alias_set_type
3188 c_common_get_alias_set (tree t)
3189 {
3190   tree u;
3191   PTR *slot;
3192
3193   /* Permit type-punning when accessing a union, provided the access
3194      is directly through the union.  For example, this code does not
3195      permit taking the address of a union member and then storing
3196      through it.  Even the type-punning allowed here is a GCC
3197      extension, albeit a common and useful one; the C standard says
3198      that such accesses have implementation-defined behavior.  */
3199   for (u = t;
3200        TREE_CODE (u) == COMPONENT_REF || TREE_CODE (u) == ARRAY_REF;
3201        u = TREE_OPERAND (u, 0))
3202     if (TREE_CODE (u) == COMPONENT_REF
3203         && TREE_CODE (TREE_TYPE (TREE_OPERAND (u, 0))) == UNION_TYPE)
3204       return 0;
3205
3206   /* That's all the expressions we handle specially.  */
3207   if (!TYPE_P (t))
3208     return -1;
3209
3210   /* The C standard guarantees that any object may be accessed via an
3211      lvalue that has character type.  */
3212   if (t == char_type_node
3213       || t == signed_char_type_node
3214       || t == unsigned_char_type_node)
3215     return 0;
3216
3217   /* If it has the may_alias attribute, it can alias anything.  */
3218   if (lookup_attribute ("may_alias", TYPE_ATTRIBUTES (t)))
3219     return 0;
3220
3221   /* The C standard specifically allows aliasing between signed and
3222      unsigned variants of the same type.  We treat the signed
3223      variant as canonical.  */
3224   if (TREE_CODE (t) == INTEGER_TYPE && TYPE_UNSIGNED (t))
3225     {
3226       tree t1 = c_common_signed_type (t);
3227
3228       /* t1 == t can happen for boolean nodes which are always unsigned.  */
3229       if (t1 != t)
3230         return get_alias_set (t1);
3231     }
3232   else if (POINTER_TYPE_P (t))
3233     {
3234       tree t1;
3235
3236       /* Unfortunately, there is no canonical form of a pointer type.
3237          In particular, if we have `typedef int I', then `int *', and
3238          `I *' are different types.  So, we have to pick a canonical
3239          representative.  We do this below.
3240
3241          Technically, this approach is actually more conservative that
3242          it needs to be.  In particular, `const int *' and `int *'
3243          should be in different alias sets, according to the C and C++
3244          standard, since their types are not the same, and so,
3245          technically, an `int **' and `const int **' cannot point at
3246          the same thing.
3247
3248          But, the standard is wrong.  In particular, this code is
3249          legal C++:
3250
3251             int *ip;
3252             int **ipp = &ip;
3253             const int* const* cipp = ipp;
3254
3255          And, it doesn't make sense for that to be legal unless you
3256          can dereference IPP and CIPP.  So, we ignore cv-qualifiers on
3257          the pointed-to types.  This issue has been reported to the
3258          C++ committee.  */
3259       t1 = build_type_no_quals (t);
3260       if (t1 != t)
3261         return get_alias_set (t1);
3262     }
3263
3264   /* Handle the case of multiple type nodes referring to "the same" type,
3265      which occurs with IMA.  These share an alias set.  FIXME:  Currently only
3266      C90 is handled.  (In C99 type compatibility is not transitive, which
3267      complicates things mightily. The alias set splay trees can theoretically
3268      represent this, but insertion is tricky when you consider all the
3269      different orders things might arrive in.) */
3270
3271   if (c_language != clk_c || flag_isoc99)
3272     return -1;
3273
3274   /* Save time if there's only one input file.  */
3275   if (num_in_fnames == 1)
3276     return -1;
3277
3278   /* Pointers need special handling if they point to any type that
3279      needs special handling (below).  */
3280   if (TREE_CODE (t) == POINTER_TYPE)
3281     {
3282       tree t2;
3283       /* Find bottom type under any nested POINTERs.  */
3284       for (t2 = TREE_TYPE (t);
3285            TREE_CODE (t2) == POINTER_TYPE;
3286            t2 = TREE_TYPE (t2))
3287         ;
3288       if (TREE_CODE (t2) != RECORD_TYPE
3289           && TREE_CODE (t2) != ENUMERAL_TYPE
3290           && TREE_CODE (t2) != QUAL_UNION_TYPE
3291           && TREE_CODE (t2) != UNION_TYPE)
3292         return -1;
3293       if (TYPE_SIZE (t2) == 0)
3294         return -1;
3295     }
3296   /* These are the only cases that need special handling.  */
3297   if (TREE_CODE (t) != RECORD_TYPE
3298       && TREE_CODE (t) != ENUMERAL_TYPE
3299       && TREE_CODE (t) != QUAL_UNION_TYPE
3300       && TREE_CODE (t) != UNION_TYPE
3301       && TREE_CODE (t) != POINTER_TYPE)
3302     return -1;
3303   /* Undefined? */
3304   if (TYPE_SIZE (t) == 0)
3305     return -1;
3306
3307   /* Look up t in hash table.  Only one of the compatible types within each
3308      alias set is recorded in the table.  */
3309   if (!type_hash_table)
3310     type_hash_table = htab_create_ggc (1021, c_type_hash,
3311             (htab_eq) lang_hooks.types_compatible_p,
3312             NULL);
3313   slot = htab_find_slot (type_hash_table, t, INSERT);
3314   if (*slot != NULL)
3315     {
3316       TYPE_ALIAS_SET (t) = TYPE_ALIAS_SET ((tree)*slot);
3317       return TYPE_ALIAS_SET ((tree)*slot);
3318     }
3319   else
3320     /* Our caller will assign and record (in t) a new alias set; all we need
3321        to do is remember t in the hash table.  */
3322     *slot = t;
3323
3324   return -1;
3325 }
3326 \f
3327 /* Compute the value of 'sizeof (TYPE)' or '__alignof__ (TYPE)', where the
3328    second parameter indicates which OPERATOR is being applied.  The COMPLAIN
3329    flag controls whether we should diagnose possibly ill-formed
3330    constructs or not.  */
3331
3332 tree
3333 c_sizeof_or_alignof_type (tree type, bool is_sizeof, int complain)
3334 {
3335   const char *op_name;
3336   tree value = NULL;
3337   enum tree_code type_code = TREE_CODE (type);
3338
3339   op_name = is_sizeof ? "sizeof" : "__alignof__";
3340
3341   if (type_code == FUNCTION_TYPE)
3342     {
3343       if (is_sizeof)
3344         {
3345           if (complain && (pedantic || warn_pointer_arith))
3346             pedwarn ("invalid application of %<sizeof%> to a function type");
3347           value = size_one_node;
3348         }
3349       else
3350         value = size_int (FUNCTION_BOUNDARY / BITS_PER_UNIT);
3351     }
3352   else if (type_code == VOID_TYPE || type_code == ERROR_MARK)
3353     {
3354       if (type_code == VOID_TYPE
3355           && complain && (pedantic || warn_pointer_arith))
3356         pedwarn ("invalid application of %qs to a void type", op_name);
3357       value = size_one_node;
3358     }
3359   else if (!COMPLETE_TYPE_P (type))
3360     {
3361       if (complain)
3362         error ("invalid application of %qs to incomplete type %qT ",
3363                op_name, type);
3364       value = size_zero_node;
3365     }
3366   else
3367     {
3368       if (is_sizeof)
3369         /* Convert in case a char is more than one unit.  */
3370         value = size_binop (CEIL_DIV_EXPR, TYPE_SIZE_UNIT (type),
3371                             size_int (TYPE_PRECISION (char_type_node)
3372                                       / BITS_PER_UNIT));
3373       else
3374         value = size_int (TYPE_ALIGN_UNIT (type));
3375     }
3376
3377   /* VALUE will have an integer type with TYPE_IS_SIZETYPE set.
3378      TYPE_IS_SIZETYPE means that certain things (like overflow) will
3379      never happen.  However, this node should really have type
3380      `size_t', which is just a typedef for an ordinary integer type.  */
3381   value = fold_convert (size_type_node, value);
3382   gcc_assert (!TYPE_IS_SIZETYPE (TREE_TYPE (value)));
3383
3384   return value;
3385 }
3386
3387 /* Implement the __alignof keyword: Return the minimum required
3388    alignment of EXPR, measured in bytes.  For VAR_DECLs,
3389    FUNCTION_DECLs and FIELD_DECLs return DECL_ALIGN (which can be set
3390    from an "aligned" __attribute__ specification).  */
3391
3392 tree
3393 c_alignof_expr (tree expr)
3394 {
3395   tree t;
3396
3397   if (VAR_OR_FUNCTION_DECL_P (expr))
3398     t = size_int (DECL_ALIGN_UNIT (expr));
3399
3400   else if (TREE_CODE (expr) == COMPONENT_REF
3401            && DECL_C_BIT_FIELD (TREE_OPERAND (expr, 1)))
3402     {
3403       error ("%<__alignof%> applied to a bit-field");
3404       t = size_one_node;
3405     }
3406   else if (TREE_CODE (expr) == COMPONENT_REF
3407            && TREE_CODE (TREE_OPERAND (expr, 1)) == FIELD_DECL)
3408     t = size_int (DECL_ALIGN_UNIT (TREE_OPERAND (expr, 1)));
3409
3410   else if (TREE_CODE (expr) == INDIRECT_REF)
3411     {
3412       tree t = TREE_OPERAND (expr, 0);
3413       tree best = t;
3414       int bestalign = TYPE_ALIGN (TREE_TYPE (TREE_TYPE (t)));
3415
3416       while ((TREE_CODE (t) == NOP_EXPR || TREE_CODE (t) == CONVERT_EXPR)
3417              && TREE_CODE (TREE_TYPE (TREE_OPERAND (t, 0))) == POINTER_TYPE)
3418         {
3419           int thisalign;
3420
3421           t = TREE_OPERAND (t, 0);
3422           thisalign = TYPE_ALIGN (TREE_TYPE (TREE_TYPE (t)));
3423           if (thisalign > bestalign)
3424             best = t, bestalign = thisalign;
3425         }
3426       return c_alignof (TREE_TYPE (TREE_TYPE (best)));
3427     }
3428   else
3429     return c_alignof (TREE_TYPE (expr));
3430
3431   return fold_convert (size_type_node, t);
3432 }
3433 \f
3434 /* Handle C and C++ default attributes.  */
3435
3436 enum built_in_attribute
3437 {
3438 #define DEF_ATTR_NULL_TREE(ENUM) ENUM,
3439 #define DEF_ATTR_INT(ENUM, VALUE) ENUM,
3440 #define DEF_ATTR_IDENT(ENUM, STRING) ENUM,
3441 #define DEF_ATTR_TREE_LIST(ENUM, PURPOSE, VALUE, CHAIN) ENUM,
3442 #include "builtin-attrs.def"
3443 #undef DEF_ATTR_NULL_TREE
3444 #undef DEF_ATTR_INT
3445 #undef DEF_ATTR_IDENT
3446 #undef DEF_ATTR_TREE_LIST
3447   ATTR_LAST
3448 };
3449
3450 static GTY(()) tree built_in_attributes[(int) ATTR_LAST];
3451
3452 static void c_init_attributes (void);
3453
3454 enum c_builtin_type
3455 {
3456 #define DEF_PRIMITIVE_TYPE(NAME, VALUE) NAME,
3457 #define DEF_FUNCTION_TYPE_0(NAME, RETURN) NAME,
3458 #define DEF_FUNCTION_TYPE_1(NAME, RETURN, ARG1) NAME,
3459 #define DEF_FUNCTION_TYPE_2(NAME, RETURN, ARG1, ARG2) NAME,
3460 #define DEF_FUNCTION_TYPE_3(NAME, RETURN, ARG1, ARG2, ARG3) NAME,
3461 #define DEF_FUNCTION_TYPE_4(NAME, RETURN, ARG1, ARG2, ARG3, ARG4) NAME,
3462 #define DEF_FUNCTION_TYPE_5(NAME, RETURN, ARG1, ARG2, ARG3, ARG4, ARG5) NAME,
3463 #define DEF_FUNCTION_TYPE_6(NAME, RETURN, ARG1, ARG2, ARG3, ARG4, ARG5, ARG6) NAME,
3464 #define DEF_FUNCTION_TYPE_7(NAME, RETURN, ARG1, ARG2, ARG3, ARG4, ARG5, ARG6, ARG7) NAME,
3465 #define DEF_FUNCTION_TYPE_VAR_0(NAME, RETURN) NAME,
3466 #define DEF_FUNCTION_TYPE_VAR_1(NAME, RETURN, ARG1) NAME,
3467 #define DEF_FUNCTION_TYPE_VAR_2(NAME, RETURN, ARG1, ARG2) NAME,
3468 #define DEF_FUNCTION_TYPE_VAR_3(NAME, RETURN, ARG1, ARG2, ARG3) NAME,
3469 #define DEF_FUNCTION_TYPE_VAR_4(NAME, RETURN, ARG1, ARG2, ARG3, ARG4) NAME,
3470 #define DEF_FUNCTION_TYPE_VAR_5(NAME, RETURN, ARG1, ARG2, ARG3, ARG4, ARG6) \
3471   NAME,
3472 #define DEF_POINTER_TYPE(NAME, TYPE) NAME,
3473 #include "builtin-types.def"
3474 #undef DEF_PRIMITIVE_TYPE
3475 #undef DEF_FUNCTION_TYPE_0
3476 #undef DEF_FUNCTION_TYPE_1
3477 #undef DEF_FUNCTION_TYPE_2
3478 #undef DEF_FUNCTION_TYPE_3
3479 #undef DEF_FUNCTION_TYPE_4
3480 #undef DEF_FUNCTION_TYPE_5
3481 #undef DEF_FUNCTION_TYPE_6
3482 #undef DEF_FUNCTION_TYPE_7
3483 #undef DEF_FUNCTION_TYPE_VAR_0
3484 #undef DEF_FUNCTION_TYPE_VAR_1
3485 #undef DEF_FUNCTION_TYPE_VAR_2
3486 #undef DEF_FUNCTION_TYPE_VAR_3
3487 #undef DEF_FUNCTION_TYPE_VAR_4
3488 #undef DEF_FUNCTION_TYPE_VAR_5
3489 #undef DEF_POINTER_TYPE
3490   BT_LAST
3491 };
3492
3493 typedef enum c_builtin_type builtin_type;
3494
3495 /* A temporary array for c_common_nodes_and_builtins.  Used in
3496    communication with def_fn_type.  */
3497 static tree builtin_types[(int) BT_LAST + 1];
3498
3499 /* A helper function for c_common_nodes_and_builtins.  Build function type
3500    for DEF with return type RET and N arguments.  If VAR is true, then the
3501    function should be variadic after those N arguments.
3502
3503    Takes special care not to ICE if any of the types involved are
3504    error_mark_node, which indicates that said type is not in fact available
3505    (see builtin_type_for_size).  In which case the function type as a whole
3506    should be error_mark_node.  */
3507
3508 static void
3509 def_fn_type (builtin_type def, builtin_type ret, bool var, int n, ...)
3510 {
3511   tree args = NULL, t;
3512   va_list list;
3513   int i;
3514
3515   va_start (list, n);
3516   for (i = 0; i < n; ++i)
3517     {
3518       builtin_type a = va_arg (list, builtin_type);
3519       t = builtin_types[a];
3520       if (t == error_mark_node)
3521         goto egress;
3522       args = tree_cons (NULL_TREE, t, args);
3523     }
3524   va_end (list);
3525
3526   args = nreverse (args);
3527   if (!var)
3528     args = chainon (args, void_list_node);
3529
3530   t = builtin_types[ret];
3531   if (t == error_mark_node)
3532     goto egress;
3533   t = build_function_type (t, args);
3534
3535  egress:
3536   builtin_types[def] = t;
3537 }
3538
3539 /* Build builtin functions common to both C and C++ language
3540    frontends.  */
3541
3542 static void
3543 c_define_builtins (tree va_list_ref_type_node, tree va_list_arg_type_node)
3544 {
3545 #define DEF_PRIMITIVE_TYPE(ENUM, VALUE) \
3546   builtin_types[ENUM] = VALUE;
3547 #define DEF_FUNCTION_TYPE_0(ENUM, RETURN) \
3548   def_fn_type (ENUM, RETURN, 0, 0);
3549 #define DEF_FUNCTION_TYPE_1(ENUM, RETURN, ARG1) \
3550   def_fn_type (ENUM, RETURN, 0, 1, ARG1);
3551 #define DEF_FUNCTION_TYPE_2(ENUM, RETURN, ARG1, ARG2) \
3552   def_fn_type (ENUM, RETURN, 0, 2, ARG1, ARG2);
3553 #define DEF_FUNCTION_TYPE_3(ENUM, RETURN, ARG1, ARG2, ARG3) \
3554   def_fn_type (ENUM, RETURN, 0, 3, ARG1, ARG2, ARG3);
3555 #define DEF_FUNCTION_TYPE_4(ENUM, RETURN, ARG1, ARG2, ARG3, ARG4) \
3556   def_fn_type (ENUM, RETURN, 0, 4, ARG1, ARG2, ARG3, ARG4);
3557 #define DEF_FUNCTION_TYPE_5(ENUM, RETURN, ARG1, ARG2, ARG3, ARG4, ARG5) \
3558   def_fn_type (ENUM, RETURN, 0, 5, ARG1, ARG2, ARG3, ARG4, ARG5);
3559 #define DEF_FUNCTION_TYPE_6(ENUM, RETURN, ARG1, ARG2, ARG3, ARG4, ARG5, \
3560                             ARG6)                                       \
3561   def_fn_type (ENUM, RETURN, 0, 6, ARG1, ARG2, ARG3, ARG4, ARG5, ARG6);
3562 #define DEF_FUNCTION_TYPE_7(ENUM, RETURN, ARG1, ARG2, ARG3, ARG4, ARG5, \
3563                             ARG6, ARG7)                                 \
3564   def_fn_type (ENUM, RETURN, 0, 7, ARG1, ARG2, ARG3, ARG4, ARG5, ARG6, ARG7);
3565 #define DEF_FUNCTION_TYPE_VAR_0(ENUM, RETURN) \
3566   def_fn_type (ENUM, RETURN, 1, 0);
3567 #define DEF_FUNCTION_TYPE_VAR_1(ENUM, RETURN, ARG1) \
3568   def_fn_type (ENUM, RETURN, 1, 1, ARG1);
3569 #define DEF_FUNCTION_TYPE_VAR_2(ENUM, RETURN, ARG1, ARG2) \
3570   def_fn_type (ENUM, RETURN, 1, 2, ARG1, ARG2);
3571 #define DEF_FUNCTION_TYPE_VAR_3(ENUM, RETURN, ARG1, ARG2, ARG3) \
3572   def_fn_type (ENUM, RETURN, 1, 3, ARG1, ARG2, ARG3);
3573 #define DEF_FUNCTION_TYPE_VAR_4(ENUM, RETURN, ARG1, ARG2, ARG3, ARG4) \
3574   def_fn_type (ENUM, RETURN, 1, 4, ARG1, ARG2, ARG3, ARG4);
3575 #define DEF_FUNCTION_TYPE_VAR_5(ENUM, RETURN, ARG1, ARG2, ARG3, ARG4, ARG5) \
3576   def_fn_type (ENUM, RETURN, 1, 5, ARG1, ARG2, ARG3, ARG4, ARG5);
3577 #define DEF_POINTER_TYPE(ENUM, TYPE) \
3578   builtin_types[(int) ENUM] = build_pointer_type (builtin_types[(int) TYPE]);
3579
3580 #include "builtin-types.def"
3581
3582 #undef DEF_PRIMITIVE_TYPE
3583 #undef DEF_FUNCTION_TYPE_1
3584 #undef DEF_FUNCTION_TYPE_2
3585 #undef DEF_FUNCTION_TYPE_3
3586 #undef DEF_FUNCTION_TYPE_4
3587 #undef DEF_FUNCTION_TYPE_5
3588 #undef DEF_FUNCTION_TYPE_6
3589 #undef DEF_FUNCTION_TYPE_VAR_0
3590 #undef DEF_FUNCTION_TYPE_VAR_1
3591 #undef DEF_FUNCTION_TYPE_VAR_2
3592 #undef DEF_FUNCTION_TYPE_VAR_3
3593 #undef DEF_FUNCTION_TYPE_VAR_4
3594 #undef DEF_FUNCTION_TYPE_VAR_5
3595 #undef DEF_POINTER_TYPE
3596   builtin_types[(int) BT_LAST] = NULL_TREE;
3597
3598   c_init_attributes ();
3599
3600 #define DEF_BUILTIN(ENUM, NAME, CLASS, TYPE, LIBTYPE, BOTH_P, FALLBACK_P, \
3601                     NONANSI_P, ATTRS, IMPLICIT, COND)                   \
3602   if (NAME && COND)                                                     \
3603     def_builtin_1 (ENUM, NAME, CLASS,                                   \
3604                    builtin_types[(int) TYPE],                           \
3605                    builtin_types[(int) LIBTYPE],                        \
3606                    BOTH_P, FALLBACK_P, NONANSI_P,                       \
3607                    built_in_attributes[(int) ATTRS], IMPLICIT);
3608 #include "builtins.def"
3609 #undef DEF_BUILTIN
3610
3611   targetm.init_builtins ();
3612
3613   build_common_builtin_nodes ();
3614
3615   if (flag_mudflap)
3616     mudflap_init ();
3617 }
3618
3619 /* Build tree nodes and builtin functions common to both C and C++ language
3620    frontends.  */
3621
3622 void
3623 c_common_nodes_and_builtins (void)
3624 {
3625   int wchar_type_size;
3626   tree array_domain_type;
3627   tree va_list_ref_type_node;
3628   tree va_list_arg_type_node;
3629
3630   /* Define `int' and `char' first so that dbx will output them first.  */
3631   record_builtin_type (RID_INT, NULL, integer_type_node);
3632   record_builtin_type (RID_CHAR, "char", char_type_node);
3633
3634   /* `signed' is the same as `int'.  FIXME: the declarations of "signed",
3635      "unsigned long", "long long unsigned" and "unsigned short" were in C++
3636      but not C.  Are the conditionals here needed?  */
3637   if (c_dialect_cxx ())
3638     record_builtin_type (RID_SIGNED, NULL, integer_type_node);
3639   record_builtin_type (RID_LONG, "long int", long_integer_type_node);
3640   record_builtin_type (RID_UNSIGNED, "unsigned int", unsigned_type_node);
3641   record_builtin_type (RID_MAX, "long unsigned int",
3642                        long_unsigned_type_node);
3643   if (c_dialect_cxx ())
3644     record_builtin_type (RID_MAX, "unsigned long", long_unsigned_type_node);
3645   record_builtin_type (RID_MAX, "long long int",
3646                        long_long_integer_type_node);
3647   record_builtin_type (RID_MAX, "long long unsigned int",
3648                        long_long_unsigned_type_node);
3649   if (c_dialect_cxx ())
3650     record_builtin_type (RID_MAX, "long long unsigned",
3651                          long_long_unsigned_type_node);
3652   record_builtin_type (RID_SHORT, "short int", short_integer_type_node);
3653   record_builtin_type (RID_MAX, "short unsigned int",
3654                        short_unsigned_type_node);
3655   if (c_dialect_cxx ())
3656     record_builtin_type (RID_MAX, "unsigned short",
3657                          short_unsigned_type_node);
3658
3659   /* Define both `signed char' and `unsigned char'.  */
3660   record_builtin_type (RID_MAX, "signed char", signed_char_type_node);
3661   record_builtin_type (RID_MAX, "unsigned char", unsigned_char_type_node);
3662
3663   /* These are types that c_common_type_for_size and
3664      c_common_type_for_mode use.  */
3665   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
3666                                          intQI_type_node));
3667   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
3668                                          intHI_type_node));
3669   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
3670                                          intSI_type_node));
3671   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
3672                                          intDI_type_node));
3673 #if HOST_BITS_PER_WIDE_INT >= 64
3674   if (targetm.scalar_mode_supported_p (TImode))
3675     lang_hooks.decls.pushdecl (build_decl (TYPE_DECL,
3676                                            get_identifier ("__int128_t"),
3677                                            intTI_type_node));
3678 #endif
3679   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
3680                                          unsigned_intQI_type_node));
3681   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
3682                                          unsigned_intHI_type_node));
3683   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
3684                                          unsigned_intSI_type_node));
3685   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
3686                                          unsigned_intDI_type_node));
3687 #if HOST_BITS_PER_WIDE_INT >= 64
3688   if (targetm.scalar_mode_supported_p (TImode))
3689     lang_hooks.decls.pushdecl (build_decl (TYPE_DECL,
3690                                            get_identifier ("__uint128_t"),
3691                                            unsigned_intTI_type_node));
3692 #endif
3693
3694   /* Create the widest literal types.  */
3695   widest_integer_literal_type_node
3696     = make_signed_type (HOST_BITS_PER_WIDE_INT * 2);
3697   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
3698                                          widest_integer_literal_type_node));
3699
3700   widest_unsigned_literal_type_node
3701     = make_unsigned_type (HOST_BITS_PER_WIDE_INT * 2);
3702   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
3703                                          widest_unsigned_literal_type_node));
3704
3705   /* `unsigned long' is the standard type for sizeof.
3706      Note that stddef.h uses `unsigned long',
3707      and this must agree, even if long and int are the same size.  */
3708   size_type_node =
3709     TREE_TYPE (identifier_global_value (get_identifier (SIZE_TYPE)));
3710   signed_size_type_node = c_common_signed_type (size_type_node);
3711   set_sizetype (size_type_node);
3712
3713   pid_type_node =
3714     TREE_TYPE (identifier_global_value (get_identifier (PID_TYPE)));
3715
3716   build_common_tree_nodes_2 (flag_short_double);
3717
3718   record_builtin_type (RID_FLOAT, NULL, float_type_node);
3719   record_builtin_type (RID_DOUBLE, NULL, double_type_node);
3720   record_builtin_type (RID_MAX, "long double", long_double_type_node);
3721
3722   /* Only supported decimal floating point extension if the target
3723      actually supports underlying modes. */
3724   if (targetm.scalar_mode_supported_p (SDmode)
3725       && targetm.scalar_mode_supported_p (DDmode)
3726       && targetm.scalar_mode_supported_p (TDmode))
3727     {
3728       record_builtin_type (RID_DFLOAT32, NULL, dfloat32_type_node);
3729       record_builtin_type (RID_DFLOAT64, NULL, dfloat64_type_node);
3730       record_builtin_type (RID_DFLOAT128, NULL, dfloat128_type_node);
3731     }
3732
3733   if (targetm.fixed_point_supported_p ())
3734     {
3735       record_builtin_type (RID_MAX, "short _Fract", short_fract_type_node);
3736       record_builtin_type (RID_FRACT, NULL, fract_type_node);
3737       record_builtin_type (RID_MAX, "long _Fract", long_fract_type_node);
3738       record_builtin_type (RID_MAX, "long long _Fract",
3739                            long_long_fract_type_node);
3740       record_builtin_type (RID_MAX, "unsigned short _Fract",
3741                            unsigned_short_fract_type_node);
3742       record_builtin_type (RID_MAX, "unsigned _Fract",
3743                            unsigned_fract_type_node);
3744       record_builtin_type (RID_MAX, "unsigned long _Fract",
3745                            unsigned_long_fract_type_node);
3746       record_builtin_type (RID_MAX, "unsigned long long _Fract",
3747                            unsigned_long_long_fract_type_node);
3748       record_builtin_type (RID_MAX, "_Sat short _Fract",
3749                            sat_short_fract_type_node);
3750       record_builtin_type (RID_MAX, "_Sat _Fract", sat_fract_type_node);
3751       record_builtin_type (RID_MAX, "_Sat long _Fract",
3752                            sat_long_fract_type_node);
3753       record_builtin_type (RID_MAX, "_Sat long long _Fract",
3754                            sat_long_long_fract_type_node);
3755       record_builtin_type (RID_MAX, "_Sat unsigned short _Fract",
3756                            sat_unsigned_short_fract_type_node);
3757       record_builtin_type (RID_MAX, "_Sat unsigned _Fract",
3758                            sat_unsigned_fract_type_node);
3759       record_builtin_type (RID_MAX, "_Sat unsigned long _Fract",
3760                            sat_unsigned_long_fract_type_node);
3761       record_builtin_type (RID_MAX, "_Sat unsigned long long _Fract",
3762                            sat_unsigned_long_long_fract_type_node);
3763       record_builtin_type (RID_MAX, "short _Accum", short_accum_type_node);
3764       record_builtin_type (RID_ACCUM, NULL, accum_type_node);
3765       record_builtin_type (RID_MAX, "long _Accum", long_accum_type_node);
3766       record_builtin_type (RID_MAX, "long long _Accum",
3767                            long_long_accum_type_node);
3768       record_builtin_type (RID_MAX, "unsigned short _Accum",
3769                            unsigned_short_accum_type_node);
3770       record_builtin_type (RID_MAX, "unsigned _Accum",
3771                            unsigned_accum_type_node);
3772       record_builtin_type (RID_MAX, "unsigned long _Accum",
3773                            unsigned_long_accum_type_node);
3774       record_builtin_type (RID_MAX, "unsigned long long _Accum",
3775                            unsigned_long_long_accum_type_node);
3776       record_builtin_type (RID_MAX, "_Sat short _Accum",
3777                            sat_short_accum_type_node);
3778       record_builtin_type (RID_MAX, "_Sat _Accum", sat_accum_type_node);
3779       record_builtin_type (RID_MAX, "_Sat long _Accum",
3780                            sat_long_accum_type_node);
3781       record_builtin_type (RID_MAX, "_Sat long long _Accum",
3782                           sat_long_long_accum_type_node);
3783       record_builtin_type (RID_MAX, "_Sat unsigned short _Accum",
3784                            sat_unsigned_short_accum_type_node);
3785       record_builtin_type (RID_MAX, "_Sat unsigned _Accum",
3786                            sat_unsigned_accum_type_node);
3787       record_builtin_type (RID_MAX, "_Sat unsigned long _Accum",
3788                            sat_unsigned_long_accum_type_node);
3789       record_builtin_type (RID_MAX, "_Sat unsigned long long _Accum",
3790                            sat_unsigned_long_long_accum_type_node);
3791
3792     }
3793
3794   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL,
3795                                          get_identifier ("complex int"),
3796                                          complex_integer_type_node));
3797   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL,
3798                                          get_identifier ("complex float"),
3799                                          complex_float_type_node));
3800   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL,
3801                                          get_identifier ("complex double"),
3802                                          complex_double_type_node));
3803   lang_hooks.decls.pushdecl
3804     (build_decl (TYPE_DECL, get_identifier ("complex long double"),
3805                  complex_long_double_type_node));
3806
3807   if (c_dialect_cxx ())
3808     /* For C++, make fileptr_type_node a distinct void * type until
3809        FILE type is defined.  */
3810     fileptr_type_node = build_variant_type_copy (ptr_type_node);
3811
3812   record_builtin_type (RID_VOID, NULL, void_type_node);
3813
3814   /* Set the TYPE_NAME for any variants that were built before
3815      record_builtin_type gave names to the built-in types. */
3816   {
3817     tree void_name = TYPE_NAME (void_type_node);
3818     TYPE_NAME (void_type_node) = NULL_TREE;
3819     TYPE_NAME (build_qualified_type (void_type_node, TYPE_QUAL_CONST))
3820       = void_name;
3821     TYPE_NAME (void_type_node) = void_name;
3822   }
3823
3824   /* This node must not be shared.  */
3825   void_zero_node = make_node (INTEGER_CST);
3826   TREE_TYPE (void_zero_node) = void_type_node;
3827
3828   void_list_node = build_void_list_node ();
3829
3830   /* Make a type to be the domain of a few array types
3831      whose domains don't really matter.
3832      200 is small enough that it always fits in size_t
3833      and large enough that it can hold most function names for the
3834      initializations of __FUNCTION__ and __PRETTY_FUNCTION__.  */
3835   array_domain_type = build_index_type (size_int (200));
3836
3837   /* Make a type for arrays of characters.
3838      With luck nothing will ever really depend on the length of this
3839      array type.  */
3840   char_array_type_node
3841     = build_array_type (char_type_node, array_domain_type);
3842
3843   /* Likewise for arrays of ints.  */
3844   int_array_type_node
3845     = build_array_type (integer_type_node, array_domain_type);
3846
3847   string_type_node = build_pointer_type (char_type_node);
3848   const_string_type_node
3849     = build_pointer_type (build_qualified_type
3850                           (char_type_node, TYPE_QUAL_CONST));
3851
3852   /* This is special for C++ so functions can be overloaded.  */
3853   wchar_type_node = get_identifier (MODIFIED_WCHAR_TYPE);
3854   wchar_type_node = TREE_TYPE (identifier_global_value (wchar_type_node));
3855   wchar_type_size = TYPE_PRECISION (wchar_type_node);
3856   if (c_dialect_cxx ())
3857     {
3858       if (TYPE_UNSIGNED (wchar_type_node))
3859         wchar_type_node = make_unsigned_type (wchar_type_size);
3860       else
3861         wchar_type_node = make_signed_type (wchar_type_size);
3862       record_builtin_type (RID_WCHAR, "wchar_t", wchar_type_node);
3863     }
3864   else
3865     {
3866       signed_wchar_type_node = c_common_signed_type (wchar_type_node);
3867       unsigned_wchar_type_node = c_common_unsigned_type (wchar_type_node);
3868     }
3869
3870   /* This is for wide string constants.  */
3871   wchar_array_type_node
3872     = build_array_type (wchar_type_node, array_domain_type);
3873
3874   wint_type_node =
3875     TREE_TYPE (identifier_global_value (get_identifier (WINT_TYPE)));
3876
3877   intmax_type_node =
3878     TREE_TYPE (identifier_global_value (get_identifier (INTMAX_TYPE)));
3879   uintmax_type_node =
3880     TREE_TYPE (identifier_global_value (get_identifier (UINTMAX_TYPE)));
3881
3882   default_function_type = build_function_type (integer_type_node, NULL_TREE);
3883   ptrdiff_type_node
3884     = TREE_TYPE (identifier_global_value (get_identifier (PTRDIFF_TYPE)));
3885   unsigned_ptrdiff_type_node = c_common_unsigned_type (ptrdiff_type_node);
3886
3887   lang_hooks.decls.pushdecl
3888     (build_decl (TYPE_DECL, get_identifier ("__builtin_va_list"),
3889                  va_list_type_node));
3890
3891   if (TREE_CODE (va_list_type_node) == ARRAY_TYPE)
3892     {
3893       va_list_arg_type_node = va_list_ref_type_node =
3894         build_pointer_type (TREE_TYPE (va_list_type_node));
3895     }
3896   else
3897     {
3898       va_list_arg_type_node = va_list_type_node;
3899       va_list_ref_type_node = build_reference_type (va_list_type_node);
3900     }
3901
3902   if (!flag_preprocess_only)
3903     c_define_builtins (va_list_ref_type_node, va_list_arg_type_node);
3904
3905   main_identifier_node = get_identifier ("main");
3906
3907   /* Create the built-in __null node.  It is important that this is
3908      not shared.  */
3909   null_node = make_node (INTEGER_CST);
3910   TREE_TYPE (null_node) = c_common_type_for_size (POINTER_SIZE, 0);
3911
3912   /* Since builtin_types isn't gc'ed, don't export these nodes.  */
3913   memset (builtin_types, 0, sizeof (builtin_types));
3914 }
3915
3916 /* Look up the function in built_in_decls that corresponds to DECL
3917    and set ASMSPEC as its user assembler name.  DECL must be a
3918    function decl that declares a builtin.  */
3919
3920 void
3921 set_builtin_user_assembler_name (tree decl, const char *asmspec)
3922 {
3923   tree builtin;
3924   gcc_assert (TREE_CODE (decl) == FUNCTION_DECL
3925               && DECL_BUILT_IN_CLASS (decl) == BUILT_IN_NORMAL
3926               && asmspec != 0);
3927
3928   builtin = built_in_decls [DECL_FUNCTION_CODE (decl)];
3929   set_user_assembler_name (builtin, asmspec);
3930   if (DECL_FUNCTION_CODE (decl) == BUILT_IN_MEMCPY)
3931     init_block_move_fn (asmspec);
3932   else if (DECL_FUNCTION_CODE (decl) == BUILT_IN_MEMSET)
3933     init_block_clear_fn (asmspec);
3934 }
3935
3936 /* The number of named compound-literals generated thus far.  */
3937 static GTY(()) int compound_literal_number;
3938
3939 /* Set DECL_NAME for DECL, a VAR_DECL for a compound-literal.  */
3940
3941 void
3942 set_compound_literal_name (tree decl)
3943 {
3944   char *name;
3945   ASM_FORMAT_PRIVATE_NAME (name, "__compound_literal",
3946                            compound_literal_number);
3947   compound_literal_number++;
3948   DECL_NAME (decl) = get_identifier (name);
3949 }
3950
3951 tree
3952 build_va_arg (tree expr, tree type)
3953 {
3954   return build1 (VA_ARG_EXPR, type, expr);
3955 }
3956
3957
3958 /* Linked list of disabled built-in functions.  */
3959
3960 typedef struct disabled_builtin
3961 {
3962   const char *name;
3963   struct disabled_builtin *next;
3964 } disabled_builtin;
3965 static disabled_builtin *disabled_builtins = NULL;
3966
3967 static bool builtin_function_disabled_p (const char *);
3968
3969 /* Disable a built-in function specified by -fno-builtin-NAME.  If NAME
3970    begins with "__builtin_", give an error.  */
3971
3972 void
3973 disable_builtin_function (const char *name)
3974 {
3975   if (strncmp (name, "__builtin_", strlen ("__builtin_")) == 0)
3976     error ("cannot disable built-in function %qs", name);
3977   else
3978     {
3979       disabled_builtin *new_disabled_builtin = XNEW (disabled_builtin);
3980       new_disabled_builtin->name = name;
3981       new_disabled_builtin->next = disabled_builtins;
3982       disabled_builtins = new_disabled_builtin;
3983     }
3984 }
3985
3986
3987 /* Return true if the built-in function NAME has been disabled, false
3988    otherwise.  */
3989
3990 static bool
3991 builtin_function_disabled_p (const char *name)
3992 {
3993   disabled_builtin *p;
3994   for (p = disabled_builtins; p != NULL; p = p->next)
3995     {
3996       if (strcmp (name, p->name) == 0)
3997         return true;
3998     }
3999   return false;
4000 }
4001
4002
4003 /* Worker for DEF_BUILTIN.
4004    Possibly define a builtin function with one or two names.
4005    Does not declare a non-__builtin_ function if flag_no_builtin, or if
4006    nonansi_p and flag_no_nonansi_builtin.  */
4007
4008 static void
4009 def_builtin_1 (enum built_in_function fncode,
4010                const char *name,
4011                enum built_in_class fnclass,
4012                tree fntype, tree libtype,
4013                bool both_p, bool fallback_p, bool nonansi_p,
4014                tree fnattrs, bool implicit_p)
4015 {
4016   tree decl;
4017   const char *libname;
4018
4019   if (fntype == error_mark_node)
4020     return;
4021
4022   gcc_assert ((!both_p && !fallback_p)
4023               || !strncmp (name, "__builtin_",
4024                            strlen ("__builtin_")));
4025
4026   libname = name + strlen ("__builtin_");
4027   decl = add_builtin_function (name, fntype, fncode, fnclass,
4028                                (fallback_p ? libname : NULL),
4029                                fnattrs);
4030   if (both_p
4031       && !flag_no_builtin && !builtin_function_disabled_p (libname)
4032       && !(nonansi_p && flag_no_nonansi_builtin))
4033     add_builtin_function (libname, libtype, fncode, fnclass,
4034                           NULL, fnattrs);
4035
4036   built_in_decls[(int) fncode] = decl;
4037   if (implicit_p)
4038     implicit_built_in_decls[(int) fncode] = decl;
4039 }
4040 \f
4041 /* Nonzero if the type T promotes to int.  This is (nearly) the
4042    integral promotions defined in ISO C99 6.3.1.1/2.  */
4043
4044 bool
4045 c_promoting_integer_type_p (const_tree t)
4046 {
4047   switch (TREE_CODE (t))
4048     {
4049     case INTEGER_TYPE:
4050       return (TYPE_MAIN_VARIANT (t) == char_type_node
4051               || TYPE_MAIN_VARIANT (t) == signed_char_type_node
4052               || TYPE_MAIN_VARIANT (t) == unsigned_char_type_node
4053               || TYPE_MAIN_VARIANT (t) == short_integer_type_node
4054               || TYPE_MAIN_VARIANT (t) == short_unsigned_type_node
4055               || TYPE_PRECISION (t) < TYPE_PRECISION (integer_type_node));
4056
4057     case ENUMERAL_TYPE:
4058       /* ??? Technically all enumerations not larger than an int
4059          promote to an int.  But this is used along code paths
4060          that only want to notice a size change.  */
4061       return TYPE_PRECISION (t) < TYPE_PRECISION (integer_type_node);
4062
4063     case BOOLEAN_TYPE:
4064       return 1;
4065
4066     default:
4067       return 0;
4068     }
4069 }
4070
4071 /* Return 1 if PARMS specifies a fixed number of parameters
4072    and none of their types is affected by default promotions.  */
4073
4074 int
4075 self_promoting_args_p (const_tree parms)
4076 {
4077   const_tree t;
4078   for (t = parms; t; t = TREE_CHAIN (t))
4079     {
4080       tree type = TREE_VALUE (t);
4081
4082       if (type == error_mark_node)
4083         continue;
4084
4085       if (TREE_CHAIN (t) == 0 && type != void_type_node)
4086         return 0;
4087
4088       if (type == 0)
4089         return 0;
4090
4091       if (TYPE_MAIN_VARIANT (type) == float_type_node)
4092         return 0;
4093
4094       if (c_promoting_integer_type_p (type))
4095         return 0;
4096     }
4097   return 1;
4098 }
4099
4100 /* Recursively examines the array elements of TYPE, until a non-array
4101    element type is found.  */
4102
4103 tree
4104 strip_array_types (tree type)
4105 {
4106   while (TREE_CODE (type) == ARRAY_TYPE)
4107     type = TREE_TYPE (type);
4108
4109   return type;
4110 }
4111
4112 /* Recursively remove any '*' or '&' operator from TYPE.  */
4113 tree
4114 strip_pointer_operator (tree t)
4115 {
4116   while (POINTER_TYPE_P (t))
4117     t = TREE_TYPE (t);
4118   return t;
4119 }
4120
4121 /* Recursively remove pointer or array type from TYPE. */
4122 tree
4123 strip_pointer_or_array_types (tree t)
4124 {
4125   while (TREE_CODE (t) == ARRAY_TYPE || POINTER_TYPE_P (t))
4126     t = TREE_TYPE (t);
4127   return t;
4128 }
4129
4130 /* Used to compare case labels.  K1 and K2 are actually tree nodes
4131    representing case labels, or NULL_TREE for a `default' label.
4132    Returns -1 if K1 is ordered before K2, -1 if K1 is ordered after
4133    K2, and 0 if K1 and K2 are equal.  */
4134
4135 int
4136 case_compare (splay_tree_key k1, splay_tree_key k2)
4137 {
4138   /* Consider a NULL key (such as arises with a `default' label) to be
4139      smaller than anything else.  */
4140   if (!k1)
4141     return k2 ? -1 : 0;
4142   else if (!k2)
4143     return k1 ? 1 : 0;
4144
4145   return tree_int_cst_compare ((tree) k1, (tree) k2);
4146 }
4147
4148 /* Process a case label for the range LOW_VALUE ... HIGH_VALUE.  If
4149    LOW_VALUE and HIGH_VALUE are both NULL_TREE then this case label is
4150    actually a `default' label.  If only HIGH_VALUE is NULL_TREE, then
4151    case label was declared using the usual C/C++ syntax, rather than
4152    the GNU case range extension.  CASES is a tree containing all the
4153    case ranges processed so far; COND is the condition for the
4154    switch-statement itself.  Returns the CASE_LABEL_EXPR created, or
4155    ERROR_MARK_NODE if no CASE_LABEL_EXPR is created.  */
4156
4157 tree
4158 c_add_case_label (splay_tree cases, tree cond, tree orig_type,
4159                   tree low_value, tree high_value)
4160 {
4161   tree type;
4162   tree label;
4163   tree case_label;
4164   splay_tree_node node;
4165
4166   /* Create the LABEL_DECL itself.  */
4167   label = create_artificial_label ();
4168
4169   /* If there was an error processing the switch condition, bail now
4170      before we get more confused.  */
4171   if (!cond || cond == error_mark_node)
4172     goto error_out;
4173
4174   if ((low_value && TREE_TYPE (low_value)
4175        && POINTER_TYPE_P (TREE_TYPE (low_value)))
4176       || (high_value && TREE_TYPE (high_value)
4177           && POINTER_TYPE_P (TREE_TYPE (high_value))))
4178     {
4179       error ("pointers are not permitted as case values");
4180       goto error_out;
4181     }
4182
4183   /* Case ranges are a GNU extension.  */
4184   if (high_value && pedantic)
4185     pedwarn ("range expressions in switch statements are non-standard");
4186
4187   type = TREE_TYPE (cond);
4188   if (low_value)
4189     {
4190       low_value = check_case_value (low_value);
4191       low_value = convert_and_check (type, low_value);
4192       if (low_value == error_mark_node)
4193         goto error_out;
4194     }
4195   if (high_value)
4196     {
4197       high_value = check_case_value (high_value);
4198       high_value = convert_and_check (type, high_value);
4199       if (high_value == error_mark_node)
4200         goto error_out;
4201     }
4202
4203   if (low_value && high_value)
4204     {
4205       /* If the LOW_VALUE and HIGH_VALUE are the same, then this isn't
4206          really a case range, even though it was written that way.
4207          Remove the HIGH_VALUE to simplify later processing.  */
4208       if (tree_int_cst_equal (low_value, high_value))
4209         high_value = NULL_TREE;
4210       else if (!tree_int_cst_lt (low_value, high_value))
4211         warning (0, "empty range specified");
4212     }
4213
4214   /* See if the case is in range of the type of the original testing
4215      expression.  If both low_value and high_value are out of range,
4216      don't insert the case label and return NULL_TREE.  */
4217   if (low_value
4218       && !check_case_bounds (type, orig_type,
4219                              &low_value, high_value ? &high_value : NULL))
4220     return NULL_TREE;
4221
4222   /* Look up the LOW_VALUE in the table of case labels we already
4223      have.  */
4224   node = splay_tree_lookup (cases, (splay_tree_key) low_value);
4225   /* If there was not an exact match, check for overlapping ranges.
4226      There's no need to do this if there's no LOW_VALUE or HIGH_VALUE;
4227      that's a `default' label and the only overlap is an exact match.  */
4228   if (!node && (low_value || high_value))
4229     {
4230       splay_tree_node low_bound;
4231       splay_tree_node high_bound;
4232
4233       /* Even though there wasn't an exact match, there might be an
4234          overlap between this case range and another case range.
4235          Since we've (inductively) not allowed any overlapping case
4236          ranges, we simply need to find the greatest low case label
4237          that is smaller that LOW_VALUE, and the smallest low case
4238          label that is greater than LOW_VALUE.  If there is an overlap
4239          it will occur in one of these two ranges.  */
4240       low_bound = splay_tree_predecessor (cases,
4241                                           (splay_tree_key) low_value);
4242       high_bound = splay_tree_successor (cases,
4243                                          (splay_tree_key) low_value);
4244
4245       /* Check to see if the LOW_BOUND overlaps.  It is smaller than
4246          the LOW_VALUE, so there is no need to check unless the
4247          LOW_BOUND is in fact itself a case range.  */
4248       if (low_bound
4249           && CASE_HIGH ((tree) low_bound->value)
4250           && tree_int_cst_compare (CASE_HIGH ((tree) low_bound->value),
4251                                     low_value) >= 0)
4252         node = low_bound;
4253       /* Check to see if the HIGH_BOUND overlaps.  The low end of that
4254          range is bigger than the low end of the current range, so we
4255          are only interested if the current range is a real range, and
4256          not an ordinary case label.  */
4257       else if (high_bound
4258                && high_value
4259                && (tree_int_cst_compare ((tree) high_bound->key,
4260                                          high_value)
4261                    <= 0))
4262         node = high_bound;
4263     }
4264   /* If there was an overlap, issue an error.  */
4265   if (node)
4266     {
4267       tree duplicate = CASE_LABEL ((tree) node->value);
4268
4269       if (high_value)
4270         {
4271           error ("duplicate (or overlapping) case value");
4272           error ("%Jthis is the first entry overlapping that value", duplicate);
4273         }
4274       else if (low_value)
4275         {
4276           error ("duplicate case value") ;
4277           error ("%Jpreviously used here", duplicate);
4278         }
4279       else
4280         {
4281           error ("multiple default labels in one switch");
4282           error ("%Jthis is the first default label", duplicate);
4283         }
4284       goto error_out;
4285     }
4286
4287   /* Add a CASE_LABEL to the statement-tree.  */
4288   case_label = add_stmt (build_case_label (low_value, high_value, label));
4289   /* Register this case label in the splay tree.  */
4290   splay_tree_insert (cases,
4291                      (splay_tree_key) low_value,
4292                      (splay_tree_value) case_label);
4293
4294   return case_label;
4295
4296  error_out:
4297   /* Add a label so that the back-end doesn't think that the beginning of
4298      the switch is unreachable.  Note that we do not add a case label, as
4299      that just leads to duplicates and thence to failure later on.  */
4300   if (!cases->root)
4301     {
4302       tree t = create_artificial_label ();
4303       add_stmt (build_stmt (LABEL_EXPR, t));
4304     }
4305   return error_mark_node;
4306 }
4307
4308 /* Subroutines of c_do_switch_warnings, called via splay_tree_foreach.
4309    Used to verify that case values match up with enumerator values.  */
4310
4311 static void
4312 match_case_to_enum_1 (tree key, tree type, tree label)
4313 {
4314   char buf[2 + 2*HOST_BITS_PER_WIDE_INT/4 + 1];
4315
4316   /* ??? Not working too hard to print the double-word value.
4317      Should perhaps be done with %lwd in the diagnostic routines?  */
4318   if (TREE_INT_CST_HIGH (key) == 0)
4319     snprintf (buf, sizeof (buf), HOST_WIDE_INT_PRINT_UNSIGNED,
4320               TREE_INT_CST_LOW (key));
4321   else if (!TYPE_UNSIGNED (type)
4322            && TREE_INT_CST_HIGH (key) == -1
4323            && TREE_INT_CST_LOW (key) != 0)
4324     snprintf (buf, sizeof (buf), "-" HOST_WIDE_INT_PRINT_UNSIGNED,
4325               -TREE_INT_CST_LOW (key));
4326   else
4327     snprintf (buf, sizeof (buf), HOST_WIDE_INT_PRINT_DOUBLE_HEX,
4328               TREE_INT_CST_HIGH (key), TREE_INT_CST_LOW (key));
4329
4330   if (TYPE_NAME (type) == 0)
4331     warning (0, "%Jcase value %qs not in enumerated type",
4332              CASE_LABEL (label), buf);
4333   else
4334     warning (0, "%Jcase value %qs not in enumerated type %qT",
4335              CASE_LABEL (label), buf, type);
4336 }
4337
4338 /* Subroutine of c_do_switch_warnings, called via splay_tree_foreach.
4339    Used to verify that case values match up with enumerator values.  */
4340
4341 static int
4342 match_case_to_enum (splay_tree_node node, void *data)
4343 {
4344   tree label = (tree) node->value;
4345   tree type = (tree) data;
4346
4347   /* Skip default case.  */
4348   if (!CASE_LOW (label))
4349     return 0;
4350
4351   /* If CASE_LOW_SEEN is not set, that means CASE_LOW did not appear
4352      when we did our enum->case scan.  Reset our scratch bit after.  */
4353   if (!CASE_LOW_SEEN (label))
4354     match_case_to_enum_1 (CASE_LOW (label), type, label);
4355   else
4356     CASE_LOW_SEEN (label) = 0;
4357
4358   /* If CASE_HIGH is non-null, we have a range.  If CASE_HIGH_SEEN is
4359      not set, that means that CASE_HIGH did not appear when we did our
4360      enum->case scan.  Reset our scratch bit after.  */
4361   if (CASE_HIGH (label))
4362     {
4363       if (!CASE_HIGH_SEEN (label))
4364         match_case_to_enum_1 (CASE_HIGH (label), type, label);
4365       else
4366         CASE_HIGH_SEEN (label) = 0;
4367     }
4368
4369   return 0;
4370 }
4371
4372 /* Handle -Wswitch*.  Called from the front end after parsing the
4373    switch construct.  */
4374 /* ??? Should probably be somewhere generic, since other languages
4375    besides C and C++ would want this.  At the moment, however, C/C++
4376    are the only tree-ssa languages that support enumerations at all,
4377    so the point is moot.  */
4378
4379 void
4380 c_do_switch_warnings (splay_tree cases, location_t switch_location,
4381                       tree type, tree cond)
4382 {
4383   splay_tree_node default_node;
4384   splay_tree_node node;
4385   tree chain;
4386
4387   if (!warn_switch && !warn_switch_enum && !warn_switch_default)
4388     return;
4389
4390   default_node = splay_tree_lookup (cases, (splay_tree_key) NULL);
4391   if (!default_node)
4392     warning (OPT_Wswitch_default, "%Hswitch missing default case",
4393              &switch_location);
4394
4395   /* From here on, we only care about about enumerated types.  */
4396   if (!type || TREE_CODE (type) != ENUMERAL_TYPE)
4397     return;
4398
4399   /* If the switch expression was an enumerated type, check that
4400      exactly all enumeration literals are covered by the cases.
4401      The check is made when -Wswitch was specified and there is no
4402      default case, or when -Wswitch-enum was specified.  */
4403
4404   if (!warn_switch_enum
4405       && !(warn_switch && !default_node))
4406     return;
4407
4408   /* Clearing COND if it is not an integer constant simplifies
4409      the tests inside the loop below.  */
4410   if (TREE_CODE (cond) != INTEGER_CST)
4411     cond = NULL_TREE;
4412
4413   /* The time complexity here is O(N*lg(N)) worst case, but for the
4414       common case of monotonically increasing enumerators, it is
4415       O(N), since the nature of the splay tree will keep the next
4416       element adjacent to the root at all times.  */
4417
4418   for (chain = TYPE_VALUES (type); chain; chain = TREE_CHAIN (chain))
4419     {
4420       tree value = TREE_VALUE (chain);
4421       node = splay_tree_lookup (cases, (splay_tree_key) value);
4422       if (node)
4423         {
4424           /* Mark the CASE_LOW part of the case entry as seen.  */
4425           tree label = (tree) node->value;
4426           CASE_LOW_SEEN (label) = 1;
4427           continue;
4428         }
4429
4430       /* Even though there wasn't an exact match, there might be a
4431          case range which includes the enumator's value.  */
4432       node = splay_tree_predecessor (cases, (splay_tree_key) value);
4433       if (node && CASE_HIGH ((tree) node->value))
4434         {
4435           tree label = (tree) node->value;
4436           int cmp = tree_int_cst_compare (CASE_HIGH (label), value);
4437           if (cmp >= 0)
4438             {
4439               /* If we match the upper bound exactly, mark the CASE_HIGH
4440                  part of the case entry as seen.  */
4441               if (cmp == 0)
4442                 CASE_HIGH_SEEN (label) = 1;
4443               continue;
4444             }
4445         }
4446
4447       /* We've now determined that this enumerated literal isn't
4448          handled by the case labels of the switch statement.  */
4449
4450       /* If the switch expression is a constant, we only really care
4451          about whether that constant is handled by the switch.  */
4452       if (cond && tree_int_cst_compare (cond, value))
4453         continue;
4454
4455       warning (0, "%Henumeration value %qE not handled in switch",
4456                &switch_location, TREE_PURPOSE (chain));
4457     }
4458
4459   /* Warn if there are case expressions that don't correspond to
4460      enumerators.  This can occur since C and C++ don't enforce
4461      type-checking of assignments to enumeration variables.
4462
4463      The time complexity here is now always O(N) worst case, since
4464      we should have marked both the lower bound and upper bound of
4465      every disjoint case label, with CASE_LOW_SEEN and CASE_HIGH_SEEN
4466      above.  This scan also resets those fields.  */
4467   splay_tree_foreach (cases, match_case_to_enum, type);
4468 }
4469
4470 /* Finish an expression taking the address of LABEL (an
4471    IDENTIFIER_NODE).  Returns an expression for the address.  */
4472
4473 tree
4474 finish_label_address_expr (tree label)
4475 {
4476   tree result;
4477
4478   if (pedantic)
4479     pedwarn ("taking the address of a label is non-standard");
4480
4481   if (label == error_mark_node)
4482     return error_mark_node;
4483
4484   label = lookup_label (label);
4485   if (label == NULL_TREE)
4486     result = null_pointer_node;
4487   else
4488     {
4489       TREE_USED (label) = 1;
4490       result = build1 (ADDR_EXPR, ptr_type_node, label);
4491       /* The current function in not necessarily uninlinable.
4492          Computed gotos are incompatible with inlining, but the value
4493          here could be used only in a diagnostic, for example.  */
4494     }
4495
4496   return result;
4497 }
4498
4499 /* Hook used by expand_expr to expand language-specific tree codes.  */
4500 /* The only things that should go here are bits needed to expand
4501    constant initializers.  Everything else should be handled by the
4502    gimplification routines.  */
4503
4504 rtx
4505 c_expand_expr (tree exp, rtx target, enum machine_mode tmode,
4506                int modifier /* Actually enum_modifier.  */,
4507                rtx *alt_rtl)
4508 {
4509   switch (TREE_CODE (exp))
4510     {
4511     case COMPOUND_LITERAL_EXPR:
4512       {
4513         /* Initialize the anonymous variable declared in the compound
4514            literal, then return the variable.  */
4515         tree decl = COMPOUND_LITERAL_EXPR_DECL (exp);
4516         emit_local_var (decl);
4517         return expand_expr_real (decl, target, tmode, modifier, alt_rtl);
4518       }
4519
4520     default:
4521       gcc_unreachable ();
4522     }
4523 }
4524
4525 /* Hook used by staticp to handle language-specific tree codes.  */
4526
4527 tree
4528 c_staticp (tree exp)
4529 {
4530   return (TREE_CODE (exp) == COMPOUND_LITERAL_EXPR
4531           && TREE_STATIC (COMPOUND_LITERAL_EXPR_DECL (exp))
4532           ? exp : NULL);
4533 }
4534 \f
4535
4536 /* Given a boolean expression ARG, return a tree representing an increment
4537    or decrement (as indicated by CODE) of ARG.  The front end must check for
4538    invalid cases (e.g., decrement in C++).  */
4539 tree
4540 boolean_increment (enum tree_code code, tree arg)
4541 {
4542   tree val;
4543   tree true_res = build_int_cst (TREE_TYPE (arg), 1);
4544
4545   arg = stabilize_reference (arg);
4546   switch (code)
4547     {
4548     case PREINCREMENT_EXPR:
4549       val = build2 (MODIFY_EXPR, TREE_TYPE (arg), arg, true_res);
4550       break;
4551     case POSTINCREMENT_EXPR:
4552       val = build2 (MODIFY_EXPR, TREE_TYPE (arg), arg, true_res);
4553       arg = save_expr (arg);
4554       val = build2 (COMPOUND_EXPR, TREE_TYPE (arg), val, arg);
4555       val = build2 (COMPOUND_EXPR, TREE_TYPE (arg), arg, val);
4556       break;
4557     case PREDECREMENT_EXPR:
4558       val = build2 (MODIFY_EXPR, TREE_TYPE (arg), arg,
4559                     invert_truthvalue (arg));
4560       break;
4561     case POSTDECREMENT_EXPR:
4562       val = build2 (MODIFY_EXPR, TREE_TYPE (arg), arg,
4563                     invert_truthvalue (arg));
4564       arg = save_expr (arg);
4565       val = build2 (COMPOUND_EXPR, TREE_TYPE (arg), val, arg);
4566       val = build2 (COMPOUND_EXPR, TREE_TYPE (arg), arg, val);
4567       break;
4568     default:
4569       gcc_unreachable ();
4570     }
4571   TREE_SIDE_EFFECTS (val) = 1;
4572   return val;
4573 }
4574 \f
4575 /* Built-in macros for stddef.h, that require macros defined in this
4576    file.  */
4577 void
4578 c_stddef_cpp_builtins(void)
4579 {
4580   builtin_define_with_value ("__SIZE_TYPE__", SIZE_TYPE, 0);
4581   builtin_define_with_value ("__PTRDIFF_TYPE__", PTRDIFF_TYPE, 0);
4582   builtin_define_with_value ("__WCHAR_TYPE__", MODIFIED_WCHAR_TYPE, 0);
4583   builtin_define_with_value ("__WINT_TYPE__", WINT_TYPE, 0);
4584   builtin_define_with_value ("__INTMAX_TYPE__", INTMAX_TYPE, 0);
4585   builtin_define_with_value ("__UINTMAX_TYPE__", UINTMAX_TYPE, 0);
4586 }
4587
4588 static void
4589 c_init_attributes (void)
4590 {
4591   /* Fill in the built_in_attributes array.  */
4592 #define DEF_ATTR_NULL_TREE(ENUM)                                \
4593   built_in_attributes[(int) ENUM] = NULL_TREE;
4594 #define DEF_ATTR_INT(ENUM, VALUE)                               \
4595   built_in_attributes[(int) ENUM] = build_int_cst (NULL_TREE, VALUE);
4596 #define DEF_ATTR_IDENT(ENUM, STRING)                            \
4597   built_in_attributes[(int) ENUM] = get_identifier (STRING);
4598 #define DEF_ATTR_TREE_LIST(ENUM, PURPOSE, VALUE, CHAIN) \
4599   built_in_attributes[(int) ENUM]                       \
4600     = tree_cons (built_in_attributes[(int) PURPOSE],    \
4601                  built_in_attributes[(int) VALUE],      \
4602                  built_in_attributes[(int) CHAIN]);
4603 #include "builtin-attrs.def"
4604 #undef DEF_ATTR_NULL_TREE
4605 #undef DEF_ATTR_INT
4606 #undef DEF_ATTR_IDENT
4607 #undef DEF_ATTR_TREE_LIST
4608 }
4609
4610 /* Attribute handlers common to C front ends.  */
4611
4612 /* Handle a "packed" attribute; arguments as in
4613    struct attribute_spec.handler.  */
4614
4615 static tree
4616 handle_packed_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4617                          int flags, bool *no_add_attrs)
4618 {
4619   if (TYPE_P (*node))
4620     {
4621       if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
4622         *node = build_variant_type_copy (*node);
4623       TYPE_PACKED (*node) = 1;
4624     }
4625   else if (TREE_CODE (*node) == FIELD_DECL)
4626     {
4627       if (TYPE_ALIGN (TREE_TYPE (*node)) <= BITS_PER_UNIT)
4628         warning (OPT_Wattributes,
4629                  "%qE attribute ignored for field of type %qT",
4630                  name, TREE_TYPE (*node));
4631       else
4632         DECL_PACKED (*node) = 1;
4633     }
4634   /* We can't set DECL_PACKED for a VAR_DECL, because the bit is
4635      used for DECL_REGISTER.  It wouldn't mean anything anyway.
4636      We can't set DECL_PACKED on the type of a TYPE_DECL, because
4637      that changes what the typedef is typing.  */
4638   else
4639     {
4640       warning (OPT_Wattributes, "%qE attribute ignored", name);
4641       *no_add_attrs = true;
4642     }
4643
4644   return NULL_TREE;
4645 }
4646
4647 /* Handle a "nocommon" attribute; arguments as in
4648    struct attribute_spec.handler.  */
4649
4650 static tree
4651 handle_nocommon_attribute (tree *node, tree name,
4652                            tree ARG_UNUSED (args),
4653                            int ARG_UNUSED (flags), bool *no_add_attrs)
4654 {
4655   if (TREE_CODE (*node) == VAR_DECL)
4656     DECL_COMMON (*node) = 0;
4657   else
4658     {
4659       warning (OPT_Wattributes, "%qE attribute ignored", name);
4660       *no_add_attrs = true;
4661     }
4662
4663   return NULL_TREE;
4664 }
4665
4666 /* Handle a "common" attribute; arguments as in
4667    struct attribute_spec.handler.  */
4668
4669 static tree
4670 handle_common_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4671                          int ARG_UNUSED (flags), bool *no_add_attrs)
4672 {
4673   if (TREE_CODE (*node) == VAR_DECL)
4674     DECL_COMMON (*node) = 1;
4675   else
4676     {
4677       warning (OPT_Wattributes, "%qE attribute ignored", name);
4678       *no_add_attrs = true;
4679     }
4680
4681   return NULL_TREE;
4682 }
4683
4684 /* Handle a "noreturn" attribute; arguments as in
4685    struct attribute_spec.handler.  */
4686
4687 static tree
4688 handle_noreturn_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4689                            int ARG_UNUSED (flags), bool *no_add_attrs)
4690 {
4691   tree type = TREE_TYPE (*node);
4692
4693   /* See FIXME comment in c_common_attribute_table.  */
4694   if (TREE_CODE (*node) == FUNCTION_DECL)
4695     TREE_THIS_VOLATILE (*node) = 1;
4696   else if (TREE_CODE (type) == POINTER_TYPE
4697            && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE)
4698     TREE_TYPE (*node)
4699       = build_pointer_type
4700         (build_type_variant (TREE_TYPE (type),
4701                              TYPE_READONLY (TREE_TYPE (type)), 1));
4702   else
4703     {
4704       warning (OPT_Wattributes, "%qE attribute ignored", name);
4705       *no_add_attrs = true;
4706     }
4707
4708   return NULL_TREE;
4709 }
4710
4711 /* Handle a "hot" and attribute; arguments as in
4712    struct attribute_spec.handler.  */
4713
4714 static tree
4715 handle_hot_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4716                           int ARG_UNUSED (flags), bool *no_add_attrs)
4717 {
4718   if (TREE_CODE (*node) == FUNCTION_DECL)
4719     {
4720       if (lookup_attribute ("cold", DECL_ATTRIBUTES (*node)) != NULL)
4721         {
4722           warning (OPT_Wattributes, "%qE attribute conflicts with attribute %s",
4723                    name, "cold");
4724           *no_add_attrs = true;
4725         }
4726       /* Do nothing else, just set the attribute.  We'll get at
4727          it later with lookup_attribute.  */
4728     }
4729   else
4730     {
4731       warning (OPT_Wattributes, "%qE attribute ignored", name);
4732       *no_add_attrs = true;
4733     }
4734
4735   return NULL_TREE;
4736 }
4737 /* Handle a "cold" and attribute; arguments as in
4738    struct attribute_spec.handler.  */
4739
4740 static tree
4741 handle_cold_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4742                        int ARG_UNUSED (flags), bool *no_add_attrs)
4743 {
4744   if (TREE_CODE (*node) == FUNCTION_DECL)
4745     {
4746       if (lookup_attribute ("hot", DECL_ATTRIBUTES (*node)) != NULL)
4747         {
4748           warning (OPT_Wattributes, "%qE attribute conflicts with attribute %s",
4749                    name, "hot");
4750           *no_add_attrs = true;
4751         }
4752       /* Do nothing else, just set the attribute.  We'll get at
4753          it later with lookup_attribute.  */
4754     }
4755   else
4756     {
4757       warning (OPT_Wattributes, "%qE attribute ignored", name);
4758       *no_add_attrs = true;
4759     }
4760
4761   return NULL_TREE;
4762 }
4763
4764 /* Handle a "noinline" attribute; arguments as in
4765    struct attribute_spec.handler.  */
4766
4767 static tree
4768 handle_noinline_attribute (tree *node, tree name,
4769                            tree ARG_UNUSED (args),
4770                            int ARG_UNUSED (flags), bool *no_add_attrs)
4771 {
4772   if (TREE_CODE (*node) == FUNCTION_DECL)
4773     DECL_UNINLINABLE (*node) = 1;
4774   else
4775     {
4776       warning (OPT_Wattributes, "%qE attribute ignored", name);
4777       *no_add_attrs = true;
4778     }
4779
4780   return NULL_TREE;
4781 }
4782
4783 /* Handle a "always_inline" attribute; arguments as in
4784    struct attribute_spec.handler.  */
4785
4786 static tree
4787 handle_always_inline_attribute (tree *node, tree name,
4788                                 tree ARG_UNUSED (args),
4789                                 int ARG_UNUSED (flags),
4790                                 bool *no_add_attrs)
4791 {
4792   if (TREE_CODE (*node) == FUNCTION_DECL)
4793     {
4794       /* Set the attribute and mark it for disregarding inline
4795          limits.  */
4796       DECL_DISREGARD_INLINE_LIMITS (*node) = 1;
4797     }
4798   else
4799     {
4800       warning (OPT_Wattributes, "%qE attribute ignored", name);
4801       *no_add_attrs = true;
4802     }
4803
4804   return NULL_TREE;
4805 }
4806
4807 /* Handle a "gnu_inline" attribute; arguments as in
4808    struct attribute_spec.handler.  */
4809
4810 static tree
4811 handle_gnu_inline_attribute (tree *node, tree name,
4812                              tree ARG_UNUSED (args),
4813                              int ARG_UNUSED (flags),
4814                              bool *no_add_attrs)
4815 {
4816   if (TREE_CODE (*node) == FUNCTION_DECL && DECL_DECLARED_INLINE_P (*node))
4817     {
4818       /* Do nothing else, just set the attribute.  We'll get at
4819          it later with lookup_attribute.  */
4820     }
4821   else
4822     {
4823       warning (OPT_Wattributes, "%qE attribute ignored", name);
4824       *no_add_attrs = true;
4825     }
4826
4827   return NULL_TREE;
4828 }
4829
4830 /* Handle an "artificial" attribute; arguments as in
4831    struct attribute_spec.handler.  */
4832
4833 static tree
4834 handle_artificial_attribute (tree *node, tree name,
4835                              tree ARG_UNUSED (args),
4836                              int ARG_UNUSED (flags),
4837                              bool *no_add_attrs)
4838 {
4839   if (TREE_CODE (*node) == FUNCTION_DECL && DECL_DECLARED_INLINE_P (*node))
4840     {
4841       /* Do nothing else, just set the attribute.  We'll get at
4842          it later with lookup_attribute.  */
4843     }
4844   else
4845     {
4846       warning (OPT_Wattributes, "%qE attribute ignored", name);
4847       *no_add_attrs = true;
4848     }
4849
4850   return NULL_TREE;
4851 }
4852
4853 /* Handle a "flatten" attribute; arguments as in
4854    struct attribute_spec.handler.  */
4855
4856 static tree
4857 handle_flatten_attribute (tree *node, tree name,
4858                           tree args ATTRIBUTE_UNUSED,
4859                           int flags ATTRIBUTE_UNUSED, bool *no_add_attrs)
4860 {
4861   if (TREE_CODE (*node) == FUNCTION_DECL)
4862     /* Do nothing else, just set the attribute.  We'll get at
4863        it later with lookup_attribute.  */
4864     ;
4865   else
4866     {
4867       warning (OPT_Wattributes, "%qE attribute ignored", name);
4868       *no_add_attrs = true;
4869     }
4870
4871   return NULL_TREE;
4872 }
4873
4874 /* Handle a "warning" or "error" attribute; arguments as in
4875    struct attribute_spec.handler.  */
4876
4877 static tree
4878 handle_error_attribute (tree *node, tree name, tree args,
4879                         int ARG_UNUSED (flags), bool *no_add_attrs)
4880 {
4881   if (TREE_CODE (*node) == FUNCTION_DECL
4882       || TREE_CODE (TREE_VALUE (args)) == STRING_CST)
4883     /* Do nothing else, just set the attribute.  We'll get at
4884        it later with lookup_attribute.  */
4885     ;
4886   else
4887     {
4888       warning (OPT_Wattributes, "%qE attribute ignored", name);
4889       *no_add_attrs = true;
4890     }
4891
4892   return NULL_TREE;
4893 }
4894
4895 /* Handle a "used" attribute; arguments as in
4896    struct attribute_spec.handler.  */
4897
4898 static tree
4899 handle_used_attribute (tree *pnode, tree name, tree ARG_UNUSED (args),
4900                        int ARG_UNUSED (flags), bool *no_add_attrs)
4901 {
4902   tree node = *pnode;
4903
4904   if (TREE_CODE (node) == FUNCTION_DECL
4905       || (TREE_CODE (node) == VAR_DECL && TREE_STATIC (node)))
4906     {
4907       TREE_USED (node) = 1;
4908       DECL_PRESERVE_P (node) = 1;
4909     }
4910   else
4911     {
4912       warning (OPT_Wattributes, "%qE attribute ignored", name);
4913       *no_add_attrs = true;
4914     }
4915
4916   return NULL_TREE;
4917 }
4918
4919 /* Handle a "unused" attribute; arguments as in
4920    struct attribute_spec.handler.  */
4921
4922 static tree
4923 handle_unused_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4924                          int flags, bool *no_add_attrs)
4925 {
4926   if (DECL_P (*node))
4927     {
4928       tree decl = *node;
4929
4930       if (TREE_CODE (decl) == PARM_DECL
4931           || TREE_CODE (decl) == VAR_DECL
4932           || TREE_CODE (decl) == FUNCTION_DECL
4933           || TREE_CODE (decl) == LABEL_DECL
4934           || TREE_CODE (decl) == TYPE_DECL)
4935         TREE_USED (decl) = 1;
4936       else
4937         {
4938           warning (OPT_Wattributes, "%qE attribute ignored", name);
4939           *no_add_attrs = true;
4940         }
4941     }
4942   else
4943     {
4944       if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
4945         *node = build_variant_type_copy (*node);
4946       TREE_USED (*node) = 1;
4947     }
4948
4949   return NULL_TREE;
4950 }
4951
4952 /* Handle a "externally_visible" attribute; arguments as in
4953    struct attribute_spec.handler.  */
4954
4955 static tree
4956 handle_externally_visible_attribute (tree *pnode, tree name,
4957                                      tree ARG_UNUSED (args),
4958                                      int ARG_UNUSED (flags),
4959                                      bool *no_add_attrs)
4960 {
4961   tree node = *pnode;
4962
4963   if (TREE_CODE (node) == FUNCTION_DECL || TREE_CODE (node) == VAR_DECL)
4964     {
4965       if ((!TREE_STATIC (node) && TREE_CODE (node) != FUNCTION_DECL
4966            && !DECL_EXTERNAL (node)) || !TREE_PUBLIC (node))
4967         {
4968           warning (OPT_Wattributes,
4969                    "%qE attribute have effect only on public objects", name);
4970           *no_add_attrs = true;
4971         }
4972     }
4973   else
4974     {
4975       warning (OPT_Wattributes, "%qE attribute ignored", name);
4976       *no_add_attrs = true;
4977     }
4978
4979   return NULL_TREE;
4980 }
4981
4982 /* Handle a "const" attribute; arguments as in
4983    struct attribute_spec.handler.  */
4984
4985 static tree
4986 handle_const_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4987                         int ARG_UNUSED (flags), bool *no_add_attrs)
4988 {
4989   tree type = TREE_TYPE (*node);
4990
4991   /* See FIXME comment on noreturn in c_common_attribute_table.  */
4992   if (TREE_CODE (*node) == FUNCTION_DECL)
4993     TREE_READONLY (*node) = 1;
4994   else if (TREE_CODE (type) == POINTER_TYPE
4995            && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE)
4996     TREE_TYPE (*node)
4997       = build_pointer_type
4998         (build_type_variant (TREE_TYPE (type), 1,
4999                              TREE_THIS_VOLATILE (TREE_TYPE (type))));
5000   else
5001     {
5002       warning (OPT_Wattributes, "%qE attribute ignored", name);
5003       *no_add_attrs = true;
5004     }
5005
5006   return NULL_TREE;
5007 }
5008
5009 /* Handle a "transparent_union" attribute; arguments as in
5010    struct attribute_spec.handler.  */
5011
5012 static tree
5013 handle_transparent_union_attribute (tree *node, tree name,
5014                                     tree ARG_UNUSED (args), int flags,
5015                                     bool *no_add_attrs)
5016 {
5017   tree type;
5018
5019   *no_add_attrs = true;
5020
5021   if (TREE_CODE (*node) == TYPE_DECL)
5022     node = &TREE_TYPE (*node);
5023   type = *node;
5024
5025   if (TREE_CODE (type) == UNION_TYPE)
5026     {
5027       /* When IN_PLACE is set, leave the check for FIELDS and MODE to
5028          the code in finish_struct.  */
5029       if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
5030         {
5031           if (TYPE_FIELDS (type) == NULL_TREE
5032               || TYPE_MODE (type) != DECL_MODE (TYPE_FIELDS (type)))
5033             goto ignored;
5034
5035           /* A type variant isn't good enough, since we don't a cast
5036              to such a type removed as a no-op.  */
5037           *node = type = build_duplicate_type (type);
5038         }
5039
5040       TYPE_TRANSPARENT_UNION (type) = 1;
5041       return NULL_TREE;
5042     }
5043
5044  ignored:
5045   warning (OPT_Wattributes, "%qE attribute ignored", name);
5046   return NULL_TREE;
5047 }
5048
5049 /* Subroutine of handle_{con,de}structor_attribute.  Evaluate ARGS to
5050    get the requested priority for a constructor or destructor,
5051    possibly issuing diagnostics for invalid or reserved
5052    priorities.  */
5053
5054 static priority_type
5055 get_priority (tree args, bool is_destructor)
5056 {
5057   HOST_WIDE_INT pri;
5058   tree arg;
5059
5060   if (!args)
5061     return DEFAULT_INIT_PRIORITY;
5062
5063   if (!SUPPORTS_INIT_PRIORITY)
5064     {
5065       if (is_destructor)
5066         error ("destructor priorities are not supported");
5067       else
5068         error ("constructor priorities are not supported");
5069       return DEFAULT_INIT_PRIORITY;
5070     }
5071
5072   arg = TREE_VALUE (args);
5073   if (!host_integerp (arg, /*pos=*/0)
5074       || !INTEGRAL_TYPE_P (TREE_TYPE (arg)))
5075     goto invalid;
5076
5077   pri = tree_low_cst (TREE_VALUE (args), /*pos=*/0);
5078   if (pri < 0 || pri > MAX_INIT_PRIORITY)
5079     goto invalid;
5080
5081   if (pri <= MAX_RESERVED_INIT_PRIORITY)
5082     {
5083       if (is_destructor)
5084         warning (0,
5085                  "destructor priorities from 0 to %d are reserved "
5086                  "for the implementation",
5087                  MAX_RESERVED_INIT_PRIORITY);
5088       else
5089         warning (0,
5090                  "constructor priorities from 0 to %d are reserved "
5091                  "for the implementation",
5092                  MAX_RESERVED_INIT_PRIORITY);
5093     }
5094   return pri;
5095
5096  invalid:
5097   if (is_destructor)
5098     error ("destructor priorities must be integers from 0 to %d inclusive",
5099            MAX_INIT_PRIORITY);
5100   else
5101     error ("constructor priorities must be integers from 0 to %d inclusive",
5102            MAX_INIT_PRIORITY);
5103   return DEFAULT_INIT_PRIORITY;
5104 }
5105
5106 /* Handle a "constructor" attribute; arguments as in
5107    struct attribute_spec.handler.  */
5108
5109 static tree
5110 handle_constructor_attribute (tree *node, tree name, tree args,
5111                               int ARG_UNUSED (flags),
5112                               bool *no_add_attrs)
5113 {
5114   tree decl = *node;
5115   tree type = TREE_TYPE (decl);
5116
5117   if (TREE_CODE (decl) == FUNCTION_DECL
5118       && TREE_CODE (type) == FUNCTION_TYPE
5119       && decl_function_context (decl) == 0)
5120     {
5121       priority_type priority;
5122       DECL_STATIC_CONSTRUCTOR (decl) = 1;
5123       priority = get_priority (args, /*is_destructor=*/false);
5124       SET_DECL_INIT_PRIORITY (decl, priority);
5125       TREE_USED (decl) = 1;
5126     }
5127   else
5128     {
5129       warning (OPT_Wattributes, "%qE attribute ignored", name);
5130       *no_add_attrs = true;
5131     }
5132
5133   return NULL_TREE;
5134 }
5135
5136 /* Handle a "destructor" attribute; arguments as in
5137    struct attribute_spec.handler.  */
5138
5139 static tree
5140 handle_destructor_attribute (tree *node, tree name, tree args,
5141                              int ARG_UNUSED (flags),
5142                              bool *no_add_attrs)
5143 {
5144   tree decl = *node;
5145   tree type = TREE_TYPE (decl);
5146
5147   if (TREE_CODE (decl) == FUNCTION_DECL
5148       && TREE_CODE (type) == FUNCTION_TYPE
5149       && decl_function_context (decl) == 0)
5150     {
5151       priority_type priority;
5152       DECL_STATIC_DESTRUCTOR (decl) = 1;
5153       priority = get_priority (args, /*is_destructor=*/true);
5154       SET_DECL_FINI_PRIORITY (decl, priority);
5155       TREE_USED (decl) = 1;
5156     }
5157   else
5158     {
5159       warning (OPT_Wattributes, "%qE attribute ignored", name);
5160       *no_add_attrs = true;
5161     }
5162
5163   return NULL_TREE;
5164 }
5165
5166 /* Handle a "mode" attribute; arguments as in
5167    struct attribute_spec.handler.  */
5168
5169 static tree
5170 handle_mode_attribute (tree *node, tree name, tree args,
5171                        int ARG_UNUSED (flags), bool *no_add_attrs)
5172 {
5173   tree type = *node;
5174
5175   *no_add_attrs = true;
5176
5177   if (TREE_CODE (TREE_VALUE (args)) != IDENTIFIER_NODE)
5178     warning (OPT_Wattributes, "%qE attribute ignored", name);
5179   else
5180     {
5181       int j;
5182       const char *p = IDENTIFIER_POINTER (TREE_VALUE (args));
5183       int len = strlen (p);
5184       enum machine_mode mode = VOIDmode;
5185       tree typefm;
5186       bool valid_mode;
5187
5188       if (len > 4 && p[0] == '_' && p[1] == '_'
5189           && p[len - 1] == '_' && p[len - 2] == '_')
5190         {
5191           char *newp = (char *) alloca (len - 1);
5192
5193           strcpy (newp, &p[2]);
5194           newp[len - 4] = '\0';
5195           p = newp;
5196         }
5197
5198       /* Change this type to have a type with the specified mode.
5199          First check for the special modes.  */
5200       if (!strcmp (p, "byte"))
5201         mode = byte_mode;
5202       else if (!strcmp (p, "word"))
5203         mode = word_mode;
5204       else if (!strcmp (p, "pointer"))
5205         mode = ptr_mode;
5206       else if (!strcmp (p, "libgcc_cmp_return"))
5207         mode = targetm.libgcc_cmp_return_mode ();
5208       else if (!strcmp (p, "libgcc_shift_count"))
5209         mode = targetm.libgcc_shift_count_mode ();
5210       else
5211         for (j = 0; j < NUM_MACHINE_MODES; j++)
5212           if (!strcmp (p, GET_MODE_NAME (j)))
5213             {
5214               mode = (enum machine_mode) j;
5215               break;
5216             }
5217
5218       if (mode == VOIDmode)
5219         {
5220           error ("unknown machine mode %qs", p);
5221           return NULL_TREE;
5222         }
5223
5224       valid_mode = false;
5225       switch (GET_MODE_CLASS (mode))
5226         {
5227         case MODE_INT:
5228         case MODE_PARTIAL_INT:
5229         case MODE_FLOAT:
5230         case MODE_DECIMAL_FLOAT:
5231         case MODE_FRACT:
5232         case MODE_UFRACT:
5233         case MODE_ACCUM:
5234         case MODE_UACCUM:
5235           valid_mode = targetm.scalar_mode_supported_p (mode);
5236           break;
5237
5238         case MODE_COMPLEX_INT:
5239         case MODE_COMPLEX_FLOAT:
5240           valid_mode = targetm.scalar_mode_supported_p (GET_MODE_INNER (mode));
5241           break;
5242
5243         case MODE_VECTOR_INT:
5244         case MODE_VECTOR_FLOAT:
5245         case MODE_VECTOR_FRACT:
5246         case MODE_VECTOR_UFRACT:
5247         case MODE_VECTOR_ACCUM:
5248         case MODE_VECTOR_UACCUM:
5249           warning (OPT_Wattributes, "specifying vector types with "
5250                    "__attribute__ ((mode)) is deprecated");
5251           warning (OPT_Wattributes,
5252                    "use __attribute__ ((vector_size)) instead");
5253           valid_mode = vector_mode_valid_p (mode);
5254           break;
5255
5256         default:
5257           break;
5258         }
5259       if (!valid_mode)
5260         {
5261           error ("unable to emulate %qs", p);
5262           return NULL_TREE;
5263         }
5264
5265       if (POINTER_TYPE_P (type))
5266         {
5267           tree (*fn)(tree, enum machine_mode, bool);
5268
5269           if (!targetm.valid_pointer_mode (mode))
5270             {
5271               error ("invalid pointer mode %qs", p);
5272               return NULL_TREE;
5273             }
5274
5275           if (TREE_CODE (type) == POINTER_TYPE)
5276             fn = build_pointer_type_for_mode;
5277           else
5278             fn = build_reference_type_for_mode;
5279           typefm = fn (TREE_TYPE (type), mode, false);
5280         }
5281       else
5282         {
5283           /* For fixed-point modes, we need to test if the signness of type
5284              and the machine mode are consistent.  */
5285           if (ALL_FIXED_POINT_MODE_P (mode)
5286               && TYPE_UNSIGNED (type) != UNSIGNED_FIXED_POINT_MODE_P (mode))
5287             {
5288               error ("signness of type and machine mode %qs don't match", p);
5289               return NULL_TREE;
5290             }
5291           /* For fixed-point modes, we need to pass saturating info.  */
5292           typefm = lang_hooks.types.type_for_mode (mode,
5293                         ALL_FIXED_POINT_MODE_P (mode) ? TYPE_SATURATING (type)
5294                                                       : TYPE_UNSIGNED (type));
5295         }
5296
5297       if (typefm == NULL_TREE)
5298         {
5299           error ("no data type for mode %qs", p);
5300           return NULL_TREE;
5301         }
5302       else if (TREE_CODE (type) == ENUMERAL_TYPE)
5303         {
5304           /* For enumeral types, copy the precision from the integer
5305              type returned above.  If not an INTEGER_TYPE, we can't use
5306              this mode for this type.  */
5307           if (TREE_CODE (typefm) != INTEGER_TYPE)
5308             {
5309               error ("cannot use mode %qs for enumeral types", p);
5310               return NULL_TREE;
5311             }
5312
5313           if (flags & ATTR_FLAG_TYPE_IN_PLACE)
5314             {
5315               TYPE_PRECISION (type) = TYPE_PRECISION (typefm);
5316               typefm = type;
5317             }
5318           else
5319             {
5320               /* We cannot build a type variant, as there's code that assumes
5321                  that TYPE_MAIN_VARIANT has the same mode.  This includes the
5322                  debug generators.  Instead, create a subrange type.  This
5323                  results in all of the enumeral values being emitted only once
5324                  in the original, and the subtype gets them by reference.  */
5325               if (TYPE_UNSIGNED (type))
5326                 typefm = make_unsigned_type (TYPE_PRECISION (typefm));
5327               else
5328                 typefm = make_signed_type (TYPE_PRECISION (typefm));
5329               TREE_TYPE (typefm) = type;
5330             }
5331         }
5332       else if (VECTOR_MODE_P (mode)
5333                ? TREE_CODE (type) != TREE_CODE (TREE_TYPE (typefm))
5334                : TREE_CODE (type) != TREE_CODE (typefm))
5335         {
5336           error ("mode %qs applied to inappropriate type", p);
5337           return NULL_TREE;
5338         }
5339
5340       *node = typefm;
5341     }
5342
5343   return NULL_TREE;
5344 }
5345
5346 /* Handle a "section" attribute; arguments as in
5347    struct attribute_spec.handler.  */
5348
5349 static tree
5350 handle_section_attribute (tree *node, tree ARG_UNUSED (name), tree args,
5351                           int ARG_UNUSED (flags), bool *no_add_attrs)
5352 {
5353   tree decl = *node;
5354
5355   if (targetm.have_named_sections)
5356     {
5357       user_defined_section_attribute = true;
5358
5359       if ((TREE_CODE (decl) == FUNCTION_DECL
5360            || TREE_CODE (decl) == VAR_DECL)
5361           && TREE_CODE (TREE_VALUE (args)) == STRING_CST)
5362         {
5363           if (TREE_CODE (decl) == VAR_DECL
5364               && current_function_decl != NULL_TREE
5365               && !TREE_STATIC (decl))
5366             {
5367               error ("%Jsection attribute cannot be specified for "
5368                      "local variables", decl);
5369               *no_add_attrs = true;
5370             }
5371
5372           /* The decl may have already been given a section attribute
5373              from a previous declaration.  Ensure they match.  */
5374           else if (DECL_SECTION_NAME (decl) != NULL_TREE
5375                    && strcmp (TREE_STRING_POINTER (DECL_SECTION_NAME (decl)),
5376                               TREE_STRING_POINTER (TREE_VALUE (args))) != 0)
5377             {
5378               error ("section of %q+D conflicts with previous declaration",
5379                      *node);
5380               *no_add_attrs = true;
5381             }
5382           else
5383             DECL_SECTION_NAME (decl) = TREE_VALUE (args);
5384         }
5385       else
5386         {
5387           error ("section attribute not allowed for %q+D", *node);
5388           *no_add_attrs = true;
5389         }
5390     }
5391   else
5392     {
5393       error ("%Jsection attributes are not supported for this target", *node);
5394       *no_add_attrs = true;
5395     }
5396
5397   return NULL_TREE;
5398 }
5399
5400 /* Handle a "aligned" attribute; arguments as in
5401    struct attribute_spec.handler.  */
5402
5403 static tree
5404 handle_aligned_attribute (tree *node, tree ARG_UNUSED (name), tree args,
5405                           int flags, bool *no_add_attrs)
5406 {
5407   tree decl = NULL_TREE;
5408   tree *type = NULL;
5409   int is_type = 0;
5410   tree align_expr = (args ? TREE_VALUE (args)
5411                      : size_int (BIGGEST_ALIGNMENT / BITS_PER_UNIT));
5412   int i;
5413
5414   if (DECL_P (*node))
5415     {
5416       decl = *node;
5417       type = &TREE_TYPE (decl);
5418       is_type = TREE_CODE (*node) == TYPE_DECL;
5419     }
5420   else if (TYPE_P (*node))
5421     type = node, is_type = 1;
5422
5423   if (TREE_CODE (align_expr) != INTEGER_CST)
5424     {
5425       error ("requested alignment is not a constant");
5426       *no_add_attrs = true;
5427     }
5428   else if ((i = tree_log2 (align_expr)) == -1)
5429     {
5430       error ("requested alignment is not a power of 2");
5431       *no_add_attrs = true;
5432     }
5433   else if (i > HOST_BITS_PER_INT - 2)
5434     {
5435       error ("requested alignment is too large");
5436       *no_add_attrs = true;
5437     }
5438   else if (is_type)
5439     {
5440       /* If we have a TYPE_DECL, then copy the type, so that we
5441          don't accidentally modify a builtin type.  See pushdecl.  */
5442       if (decl && TREE_TYPE (decl) != error_mark_node
5443           && DECL_ORIGINAL_TYPE (decl) == NULL_TREE)
5444         {
5445           tree tt = TREE_TYPE (decl);
5446           *type = build_variant_type_copy (*type);
5447           DECL_ORIGINAL_TYPE (decl) = tt;
5448           TYPE_NAME (*type) = decl;
5449           TREE_USED (*type) = TREE_USED (decl);
5450           TREE_TYPE (decl) = *type;
5451         }
5452       else if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
5453         *type = build_variant_type_copy (*type);
5454
5455       TYPE_ALIGN (*type) = (1 << i) * BITS_PER_UNIT;
5456       TYPE_USER_ALIGN (*type) = 1;
5457     }
5458   else if (! VAR_OR_FUNCTION_DECL_P (decl)
5459            && TREE_CODE (decl) != FIELD_DECL)
5460     {
5461       error ("alignment may not be specified for %q+D", decl);
5462       *no_add_attrs = true;
5463     }
5464   else if (TREE_CODE (decl) == FUNCTION_DECL
5465            && DECL_ALIGN (decl) > (1 << i) * BITS_PER_UNIT)
5466     {
5467       if (DECL_USER_ALIGN (decl))
5468         error ("alignment for %q+D was previously specified as %d "
5469                "and may not be decreased", decl,
5470                DECL_ALIGN (decl) / BITS_PER_UNIT);
5471       else
5472         error ("alignment for %q+D must be at least %d", decl,
5473                DECL_ALIGN (decl) / BITS_PER_UNIT);
5474       *no_add_attrs = true;
5475     }
5476   else
5477     {
5478       DECL_ALIGN (decl) = (1 << i) * BITS_PER_UNIT;
5479       DECL_USER_ALIGN (decl) = 1;
5480     }
5481
5482   return NULL_TREE;
5483 }
5484
5485 /* Handle a "weak" attribute; arguments as in
5486    struct attribute_spec.handler.  */
5487
5488 static tree
5489 handle_weak_attribute (tree *node, tree name,
5490                        tree ARG_UNUSED (args),
5491                        int ARG_UNUSED (flags),
5492                        bool * ARG_UNUSED (no_add_attrs))
5493 {
5494   if (TREE_CODE (*node) == FUNCTION_DECL
5495       || TREE_CODE (*node) == VAR_DECL)
5496     declare_weak (*node);
5497   else
5498     warning (OPT_Wattributes, "%qE attribute ignored", name);
5499
5500
5501   return NULL_TREE;
5502 }
5503
5504 /* Handle an "alias" attribute; arguments as in
5505    struct attribute_spec.handler.  */
5506
5507 static tree
5508 handle_alias_attribute (tree *node, tree name, tree args,
5509                         int ARG_UNUSED (flags), bool *no_add_attrs)
5510 {
5511   tree decl = *node;
5512
5513   if ((TREE_CODE (decl) == FUNCTION_DECL && DECL_INITIAL (decl))
5514       || (TREE_CODE (decl) != FUNCTION_DECL
5515           && TREE_PUBLIC (decl) && !DECL_EXTERNAL (decl))
5516       /* A static variable declaration is always a tentative definition,
5517          but the alias is a non-tentative definition which overrides.  */
5518       || (TREE_CODE (decl) != FUNCTION_DECL
5519           && ! TREE_PUBLIC (decl) && DECL_INITIAL (decl)))
5520     {
5521       error ("%q+D defined both normally and as an alias", decl);
5522       *no_add_attrs = true;
5523     }
5524
5525   /* Note that the very first time we process a nested declaration,
5526      decl_function_context will not be set.  Indeed, *would* never
5527      be set except for the DECL_INITIAL/DECL_EXTERNAL frobbery that
5528      we do below.  After such frobbery, pushdecl would set the context.
5529      In any case, this is never what we want.  */
5530   else if (decl_function_context (decl) == 0 && current_function_decl == NULL)
5531     {
5532       tree id;
5533
5534       id = TREE_VALUE (args);
5535       if (TREE_CODE (id) != STRING_CST)
5536         {
5537           error ("alias argument not a string");
5538           *no_add_attrs = true;
5539           return NULL_TREE;
5540         }
5541       id = get_identifier (TREE_STRING_POINTER (id));
5542       /* This counts as a use of the object pointed to.  */
5543       TREE_USED (id) = 1;
5544
5545       if (TREE_CODE (decl) == FUNCTION_DECL)
5546         DECL_INITIAL (decl) = error_mark_node;
5547       else
5548         {
5549           if (lookup_attribute ("weakref", DECL_ATTRIBUTES (decl)))
5550             DECL_EXTERNAL (decl) = 1;
5551           else
5552             DECL_EXTERNAL (decl) = 0;
5553           TREE_STATIC (decl) = 1;
5554         }
5555     }
5556   else
5557     {
5558       warning (OPT_Wattributes, "%qE attribute ignored", name);
5559       *no_add_attrs = true;
5560     }
5561
5562   return NULL_TREE;
5563 }
5564
5565 /* Handle a "weakref" attribute; arguments as in struct
5566    attribute_spec.handler.  */
5567
5568 static tree
5569 handle_weakref_attribute (tree *node, tree ARG_UNUSED (name), tree args,
5570                           int flags, bool *no_add_attrs)
5571 {
5572   tree attr = NULL_TREE;
5573
5574   /* We must ignore the attribute when it is associated with
5575      local-scoped decls, since attribute alias is ignored and many
5576      such symbols do not even have a DECL_WEAK field.  */
5577   if (decl_function_context (*node) || current_function_decl)
5578     {
5579       warning (OPT_Wattributes, "%qE attribute ignored", name);
5580       *no_add_attrs = true;
5581       return NULL_TREE;
5582     }
5583
5584   /* The idea here is that `weakref("name")' mutates into `weakref,
5585      alias("name")', and weakref without arguments, in turn,
5586      implicitly adds weak. */
5587
5588   if (args)
5589     {
5590       attr = tree_cons (get_identifier ("alias"), args, attr);
5591       attr = tree_cons (get_identifier ("weakref"), NULL_TREE, attr);
5592
5593       *no_add_attrs = true;
5594
5595       decl_attributes (node, attr, flags);
5596     }
5597   else
5598     {
5599       if (lookup_attribute ("alias", DECL_ATTRIBUTES (*node)))
5600         error ("%Jweakref attribute must appear before alias attribute",
5601                *node);
5602
5603       /* Can't call declare_weak because it wants this to be TREE_PUBLIC,
5604          and that isn't supported; and because it wants to add it to
5605          the list of weak decls, which isn't helpful.  */
5606       DECL_WEAK (*node) = 1;
5607     }
5608
5609   return NULL_TREE;
5610 }
5611
5612 /* Handle an "visibility" attribute; arguments as in
5613    struct attribute_spec.handler.  */
5614
5615 static tree
5616 handle_visibility_attribute (tree *node, tree name, tree args,
5617                              int ARG_UNUSED (flags),
5618                              bool *ARG_UNUSED (no_add_attrs))
5619 {
5620   tree decl = *node;
5621   tree id = TREE_VALUE (args);
5622   enum symbol_visibility vis;
5623
5624   if (TYPE_P (*node))
5625     {
5626       if (TREE_CODE (*node) == ENUMERAL_TYPE)
5627         /* OK */;
5628       else if (TREE_CODE (*node) != RECORD_TYPE && TREE_CODE (*node) != UNION_TYPE)
5629         {
5630           warning (OPT_Wattributes, "%qE attribute ignored on non-class types",
5631                    name);
5632           return NULL_TREE;
5633         }
5634       else if (TYPE_FIELDS (*node))
5635         {
5636           error ("%qE attribute ignored because %qT is already defined",
5637                  name, *node);
5638           return NULL_TREE;
5639         }
5640     }
5641   else if (decl_function_context (decl) != 0 || !TREE_PUBLIC (decl))
5642     {
5643       warning (OPT_Wattributes, "%qE attribute ignored", name);
5644       return NULL_TREE;
5645     }
5646
5647   if (TREE_CODE (id) != STRING_CST)
5648     {
5649       error ("visibility argument not a string");
5650       return NULL_TREE;
5651     }
5652
5653   /*  If this is a type, set the visibility on the type decl.  */
5654   if (TYPE_P (decl))
5655     {
5656       decl = TYPE_NAME (decl);
5657       if (!decl)
5658         return NULL_TREE;
5659       if (TREE_CODE (decl) == IDENTIFIER_NODE)
5660         {
5661            warning (OPT_Wattributes, "%qE attribute ignored on types",
5662                     name);
5663            return NULL_TREE;
5664         }
5665     }
5666
5667   if (strcmp (TREE_STRING_POINTER (id), "default") == 0)
5668     vis = VISIBILITY_DEFAULT;
5669   else if (strcmp (TREE_STRING_POINTER (id), "internal") == 0)
5670     vis = VISIBILITY_INTERNAL;
5671   else if (strcmp (TREE_STRING_POINTER (id), "hidden") == 0)
5672     vis = VISIBILITY_HIDDEN;
5673   else if (strcmp (TREE_STRING_POINTER (id), "protected") == 0)
5674     vis = VISIBILITY_PROTECTED;
5675   else
5676     {
5677       error ("visibility argument must be one of \"default\", \"hidden\", \"protected\" or \"internal\"");
5678       vis = VISIBILITY_DEFAULT;
5679     }
5680
5681   if (DECL_VISIBILITY_SPECIFIED (decl)
5682       && vis != DECL_VISIBILITY (decl))
5683     {
5684       tree attributes = (TYPE_P (*node)
5685                          ? TYPE_ATTRIBUTES (*node)
5686                          : DECL_ATTRIBUTES (decl));
5687       if (lookup_attribute ("visibility", attributes))
5688         error ("%qD redeclared with different visibility", decl);
5689       else if (TARGET_DLLIMPORT_DECL_ATTRIBUTES
5690                && lookup_attribute ("dllimport", attributes))
5691         error ("%qD was declared %qs which implies default visibility",
5692                decl, "dllimport");
5693       else if (TARGET_DLLIMPORT_DECL_ATTRIBUTES
5694                && lookup_attribute ("dllexport", attributes))
5695         error ("%qD was declared %qs which implies default visibility",
5696                decl, "dllexport");
5697     }
5698
5699   DECL_VISIBILITY (decl) = vis;
5700   DECL_VISIBILITY_SPECIFIED (decl) = 1;
5701
5702   /* Go ahead and attach the attribute to the node as well.  This is needed
5703      so we can determine whether we have VISIBILITY_DEFAULT because the
5704      visibility was not specified, or because it was explicitly overridden
5705      from the containing scope.  */
5706
5707   return NULL_TREE;
5708 }
5709
5710 /* Determine the ELF symbol visibility for DECL, which is either a
5711    variable or a function.  It is an error to use this function if a
5712    definition of DECL is not available in this translation unit.
5713    Returns true if the final visibility has been determined by this
5714    function; false if the caller is free to make additional
5715    modifications.  */
5716
5717 bool
5718 c_determine_visibility (tree decl)
5719 {
5720   gcc_assert (TREE_CODE (decl) == VAR_DECL
5721               || TREE_CODE (decl) == FUNCTION_DECL);
5722
5723   /* If the user explicitly specified the visibility with an
5724      attribute, honor that.  DECL_VISIBILITY will have been set during
5725      the processing of the attribute.  We check for an explicit
5726      attribute, rather than just checking DECL_VISIBILITY_SPECIFIED,
5727      to distinguish the use of an attribute from the use of a "#pragma
5728      GCC visibility push(...)"; in the latter case we still want other
5729      considerations to be able to overrule the #pragma.  */
5730   if (lookup_attribute ("visibility", DECL_ATTRIBUTES (decl))
5731       || (TARGET_DLLIMPORT_DECL_ATTRIBUTES
5732           && (lookup_attribute ("dllimport", DECL_ATTRIBUTES (decl))
5733               || lookup_attribute ("dllexport", DECL_ATTRIBUTES (decl)))))
5734     return true;
5735
5736   /* Set default visibility to whatever the user supplied with
5737      visibility_specified depending on #pragma GCC visibility.  */
5738   if (!DECL_VISIBILITY_SPECIFIED (decl))
5739     {
5740       DECL_VISIBILITY (decl) = default_visibility;
5741       DECL_VISIBILITY_SPECIFIED (decl) = visibility_options.inpragma;
5742     }
5743   return false;
5744 }
5745
5746 /* Handle an "tls_model" attribute; arguments as in
5747    struct attribute_spec.handler.  */
5748
5749 static tree
5750 handle_tls_model_attribute (tree *node, tree name, tree args,
5751                             int ARG_UNUSED (flags), bool *no_add_attrs)
5752 {
5753   tree id;
5754   tree decl = *node;
5755   enum tls_model kind;
5756
5757   *no_add_attrs = true;
5758
5759   if (!DECL_THREAD_LOCAL_P (decl))
5760     {
5761       warning (OPT_Wattributes, "%qE attribute ignored", name);
5762       return NULL_TREE;
5763     }
5764
5765   kind = DECL_TLS_MODEL (decl);
5766   id = TREE_VALUE (args);
5767   if (TREE_CODE (id) != STRING_CST)
5768     {
5769       error ("tls_model argument not a string");
5770       return NULL_TREE;
5771     }
5772
5773   if (!strcmp (TREE_STRING_POINTER (id), "local-exec"))
5774     kind = TLS_MODEL_LOCAL_EXEC;
5775   else if (!strcmp (TREE_STRING_POINTER (id), "initial-exec"))
5776     kind = TLS_MODEL_INITIAL_EXEC;
5777   else if (!strcmp (TREE_STRING_POINTER (id), "local-dynamic"))
5778     kind = optimize ? TLS_MODEL_LOCAL_DYNAMIC : TLS_MODEL_GLOBAL_DYNAMIC;
5779   else if (!strcmp (TREE_STRING_POINTER (id), "global-dynamic"))
5780     kind = TLS_MODEL_GLOBAL_DYNAMIC;
5781   else
5782     error ("tls_model argument must be one of \"local-exec\", \"initial-exec\", \"local-dynamic\" or \"global-dynamic\"");
5783
5784   DECL_TLS_MODEL (decl) = kind;
5785   return NULL_TREE;
5786 }
5787
5788 /* Handle a "no_instrument_function" attribute; arguments as in
5789    struct attribute_spec.handler.  */
5790
5791 static tree
5792 handle_no_instrument_function_attribute (tree *node, tree name,
5793                                          tree ARG_UNUSED (args),
5794                                          int ARG_UNUSED (flags),
5795                                          bool *no_add_attrs)
5796 {
5797   tree decl = *node;
5798
5799   if (TREE_CODE (decl) != FUNCTION_DECL)
5800     {
5801       error ("%J%qE attribute applies only to functions", decl, name);
5802       *no_add_attrs = true;
5803     }
5804   else if (DECL_INITIAL (decl))
5805     {
5806       error ("%Jcan%'t set %qE attribute after definition", decl, name);
5807       *no_add_attrs = true;
5808     }
5809   else
5810     DECL_NO_INSTRUMENT_FUNCTION_ENTRY_EXIT (decl) = 1;
5811
5812   return NULL_TREE;
5813 }
5814
5815 /* Handle a "malloc" attribute; arguments as in
5816    struct attribute_spec.handler.  */
5817
5818 static tree
5819 handle_malloc_attribute (tree *node, tree name, tree ARG_UNUSED (args),
5820                          int ARG_UNUSED (flags), bool *no_add_attrs)
5821 {
5822   if (TREE_CODE (*node) == FUNCTION_DECL
5823       && POINTER_TYPE_P (TREE_TYPE (TREE_TYPE (*node))))
5824     DECL_IS_MALLOC (*node) = 1;
5825   else
5826     {
5827       warning (OPT_Wattributes, "%qE attribute ignored", name);
5828       *no_add_attrs = true;
5829     }
5830
5831   return NULL_TREE;
5832 }
5833
5834 /* Handle a "alloc_size" attribute; arguments as in
5835    struct attribute_spec.handler.  */
5836
5837 static tree
5838 handle_alloc_size_attribute (tree *node, tree ARG_UNUSED (name), tree args,
5839                              int ARG_UNUSED (flags), bool *no_add_attrs)
5840 {
5841   tree params = TYPE_ARG_TYPES (*node);
5842   unsigned arg_count = 0;
5843
5844   for (; TREE_CHAIN (params); params = TREE_CHAIN (params))
5845     arg_count ++;
5846
5847   for (; args; args = TREE_CHAIN (args))
5848     {
5849       tree position = TREE_VALUE (args);
5850
5851       if (TREE_CODE (position) != INTEGER_CST
5852           || TREE_INT_CST_HIGH (position)
5853           || TREE_INT_CST_LOW (position) < 1
5854           || TREE_INT_CST_LOW (position) > arg_count )
5855         {
5856           warning (OPT_Wattributes,
5857                    "alloc_size parameter outside range");
5858           *no_add_attrs = true;
5859           return NULL_TREE;
5860         }
5861     }
5862   return NULL_TREE;
5863 }
5864
5865 /* Handle a "returns_twice" attribute; arguments as in
5866    struct attribute_spec.handler.  */
5867
5868 static tree
5869 handle_returns_twice_attribute (tree *node, tree name, tree ARG_UNUSED (args),
5870                          int ARG_UNUSED (flags), bool *no_add_attrs)
5871 {
5872   if (TREE_CODE (*node) == FUNCTION_DECL)
5873     DECL_IS_RETURNS_TWICE (*node) = 1;
5874   else
5875     {
5876       warning (OPT_Wattributes, "%qE attribute ignored", name);
5877       *no_add_attrs = true;
5878     }
5879
5880   return NULL_TREE;
5881 }
5882
5883 /* Handle a "no_limit_stack" attribute; arguments as in
5884    struct attribute_spec.handler.  */
5885
5886 static tree
5887 handle_no_limit_stack_attribute (tree *node, tree name,
5888                                  tree ARG_UNUSED (args),
5889                                  int ARG_UNUSED (flags),
5890                                  bool *no_add_attrs)
5891 {
5892   tree decl = *node;
5893
5894   if (TREE_CODE (decl) != FUNCTION_DECL)
5895     {
5896       error ("%J%qE attribute applies only to functions", decl, name);
5897       *no_add_attrs = true;
5898     }
5899   else if (DECL_INITIAL (decl))
5900     {
5901       error ("%Jcan%'t set %qE attribute after definition", decl, name);
5902       *no_add_attrs = true;
5903     }
5904   else
5905     DECL_NO_LIMIT_STACK (decl) = 1;
5906
5907   return NULL_TREE;
5908 }
5909
5910 /* Handle a "pure" attribute; arguments as in
5911    struct attribute_spec.handler.  */
5912
5913 static tree
5914 handle_pure_attribute (tree *node, tree name, tree ARG_UNUSED (args),
5915                        int ARG_UNUSED (flags), bool *no_add_attrs)
5916 {
5917   if (TREE_CODE (*node) == FUNCTION_DECL)
5918     DECL_IS_PURE (*node) = 1;
5919   /* ??? TODO: Support types.  */
5920   else
5921     {
5922       warning (OPT_Wattributes, "%qE attribute ignored", name);
5923       *no_add_attrs = true;
5924     }
5925
5926   return NULL_TREE;
5927 }
5928
5929 /* Handle a "no vops" attribute; arguments as in
5930    struct attribute_spec.handler.  */
5931
5932 static tree
5933 handle_novops_attribute (tree *node, tree ARG_UNUSED (name),
5934                          tree ARG_UNUSED (args), int ARG_UNUSED (flags),
5935                          bool *ARG_UNUSED (no_add_attrs))
5936 {
5937   gcc_assert (TREE_CODE (*node) == FUNCTION_DECL);
5938   DECL_IS_NOVOPS (*node) = 1;
5939   return NULL_TREE;
5940 }
5941
5942 /* Handle a "deprecated" attribute; arguments as in
5943    struct attribute_spec.handler.  */
5944
5945 static tree
5946 handle_deprecated_attribute (tree *node, tree name,
5947                              tree ARG_UNUSED (args), int flags,
5948                              bool *no_add_attrs)
5949 {
5950   tree type = NULL_TREE;
5951   int warn = 0;
5952   tree what = NULL_TREE;
5953
5954   if (DECL_P (*node))
5955     {
5956       tree decl = *node;
5957       type = TREE_TYPE (decl);
5958
5959       if (TREE_CODE (decl) == TYPE_DECL
5960           || TREE_CODE (decl) == PARM_DECL
5961           || TREE_CODE (decl) == VAR_DECL
5962           || TREE_CODE (decl) == FUNCTION_DECL
5963           || TREE_CODE (decl) == FIELD_DECL)
5964         TREE_DEPRECATED (decl) = 1;
5965       else
5966         warn = 1;
5967     }
5968   else if (TYPE_P (*node))
5969     {
5970       if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
5971         *node = build_variant_type_copy (*node);
5972       TREE_DEPRECATED (*node) = 1;
5973       type = *node;
5974     }
5975   else
5976     warn = 1;
5977
5978   if (warn)
5979     {
5980       *no_add_attrs = true;
5981       if (type && TYPE_NAME (type))
5982         {
5983           if (TREE_CODE (TYPE_NAME (type)) == IDENTIFIER_NODE)
5984             what = TYPE_NAME (*node);
5985           else if (TREE_CODE (TYPE_NAME (type)) == TYPE_DECL
5986                    && DECL_NAME (TYPE_NAME (type)))
5987             what = DECL_NAME (TYPE_NAME (type));
5988         }
5989       if (what)
5990         warning (OPT_Wattributes, "%qE attribute ignored for %qE", name, what);
5991       else
5992         warning (OPT_Wattributes, "%qE attribute ignored", name);
5993     }
5994
5995   return NULL_TREE;
5996 }
5997
5998 /* Handle a "vector_size" attribute; arguments as in
5999    struct attribute_spec.handler.  */
6000
6001 static tree
6002 handle_vector_size_attribute (tree *node, tree name, tree args,
6003                               int ARG_UNUSED (flags),
6004                               bool *no_add_attrs)
6005 {
6006   unsigned HOST_WIDE_INT vecsize, nunits;
6007   enum machine_mode orig_mode;
6008   tree type = *node, new_type, size;
6009
6010   *no_add_attrs = true;
6011
6012   size = TREE_VALUE (args);
6013
6014   if (!host_integerp (size, 1))
6015     {
6016       warning (OPT_Wattributes, "%qE attribute ignored", name);
6017       return NULL_TREE;
6018     }
6019
6020   /* Get the vector size (in bytes).  */
6021   vecsize = tree_low_cst (size, 1);
6022
6023   /* We need to provide for vector pointers, vector arrays, and
6024      functions returning vectors.  For example:
6025
6026        __attribute__((vector_size(16))) short *foo;
6027
6028      In this case, the mode is SI, but the type being modified is
6029      HI, so we need to look further.  */
6030
6031   while (POINTER_TYPE_P (type)
6032          || TREE_CODE (type) == FUNCTION_TYPE
6033          || TREE_CODE (type) == METHOD_TYPE
6034          || TREE_CODE (type) == ARRAY_TYPE
6035          || TREE_CODE (type) == OFFSET_TYPE)
6036     type = TREE_TYPE (type);
6037
6038   /* Get the mode of the type being modified.  */
6039   orig_mode = TYPE_MODE (type);
6040
6041   if ((!INTEGRAL_TYPE_P (type)
6042        && !SCALAR_FLOAT_TYPE_P (type)
6043        && !FIXED_POINT_TYPE_P (type))
6044       || (!SCALAR_FLOAT_MODE_P (orig_mode)
6045           && GET_MODE_CLASS (orig_mode) != MODE_INT
6046           && !ALL_SCALAR_FIXED_POINT_MODE_P (orig_mode))
6047       || !host_integerp (TYPE_SIZE_UNIT (type), 1))
6048     {
6049       error ("invalid vector type for attribute %qE", name);
6050       return NULL_TREE;
6051     }
6052
6053   if (vecsize % tree_low_cst (TYPE_SIZE_UNIT (type), 1))
6054     {
6055       error ("vector size not an integral multiple of component size");
6056       return NULL;
6057     }
6058
6059   if (vecsize == 0)
6060     {
6061       error ("zero vector size");
6062       return NULL;
6063     }
6064
6065   /* Calculate how many units fit in the vector.  */
6066   nunits = vecsize / tree_low_cst (TYPE_SIZE_UNIT (type), 1);
6067   if (nunits & (nunits - 1))
6068     {
6069       error ("number of components of the vector not a power of two");
6070       return NULL_TREE;
6071     }
6072
6073   new_type = build_vector_type (type, nunits);
6074
6075   /* Build back pointers if needed.  */
6076   *node = reconstruct_complex_type (*node, new_type);
6077
6078   return NULL_TREE;
6079 }
6080
6081 /* Handle the "nonnull" attribute.  */
6082 static tree
6083 handle_nonnull_attribute (tree *node, tree ARG_UNUSED (name),
6084                           tree args, int ARG_UNUSED (flags),
6085                           bool *no_add_attrs)
6086 {
6087   tree type = *node;
6088   unsigned HOST_WIDE_INT attr_arg_num;
6089
6090   /* If no arguments are specified, all pointer arguments should be
6091      non-null.  Verify a full prototype is given so that the arguments
6092      will have the correct types when we actually check them later.  */
6093   if (!args)
6094     {
6095       if (!TYPE_ARG_TYPES (type))
6096         {
6097           error ("nonnull attribute without arguments on a non-prototype");
6098           *no_add_attrs = true;
6099         }
6100       return NULL_TREE;
6101     }
6102
6103   /* Argument list specified.  Verify that each argument number references
6104      a pointer argument.  */
6105   for (attr_arg_num = 1; args; args = TREE_CHAIN (args))
6106     {
6107       tree argument;
6108       unsigned HOST_WIDE_INT arg_num = 0, ck_num;
6109
6110       if (!get_nonnull_operand (TREE_VALUE (args), &arg_num))
6111         {
6112           error ("nonnull argument has invalid operand number (argument %lu)",
6113                  (unsigned long) attr_arg_num);
6114           *no_add_attrs = true;
6115           return NULL_TREE;
6116         }
6117
6118       argument = TYPE_ARG_TYPES (type);
6119       if (argument)
6120         {
6121           for (ck_num = 1; ; ck_num++)
6122             {
6123               if (!argument || ck_num == arg_num)
6124                 break;
6125               argument = TREE_CHAIN (argument);
6126             }
6127
6128           if (!argument
6129               || TREE_CODE (TREE_VALUE (argument)) == VOID_TYPE)
6130             {
6131               error ("nonnull argument with out-of-range operand number (argument %lu, operand %lu)",
6132                      (unsigned long) attr_arg_num, (unsigned long) arg_num);
6133               *no_add_attrs = true;
6134               return NULL_TREE;
6135             }
6136
6137           if (TREE_CODE (TREE_VALUE (argument)) != POINTER_TYPE)
6138             {
6139               error ("nonnull argument references non-pointer operand (argument %lu, operand %lu)",
6140                    (unsigned long) attr_arg_num, (unsigned long) arg_num);
6141               *no_add_attrs = true;
6142               return NULL_TREE;
6143             }
6144         }
6145     }
6146
6147   return NULL_TREE;
6148 }
6149
6150 /* Check the argument list of a function call for null in argument slots
6151    that are marked as requiring a non-null pointer argument.  The NARGS
6152    arguments are passed in the array ARGARRAY.
6153 */
6154
6155 static void
6156 check_function_nonnull (tree attrs, int nargs, tree *argarray)
6157 {
6158   tree a, args;
6159   int i;
6160
6161   for (a = attrs; a; a = TREE_CHAIN (a))
6162     {
6163       if (is_attribute_p ("nonnull", TREE_PURPOSE (a)))
6164         {
6165           args = TREE_VALUE (a);
6166
6167           /* Walk the argument list.  If we encounter an argument number we
6168              should check for non-null, do it.  If the attribute has no args,
6169              then every pointer argument is checked (in which case the check
6170              for pointer type is done in check_nonnull_arg).  */
6171           for (i = 0; i < nargs; i++)
6172             {
6173               if (!args || nonnull_check_p (args, i + 1))
6174                 check_function_arguments_recurse (check_nonnull_arg, NULL,
6175                                                   argarray[i],
6176                                                   i + 1);
6177             }
6178         }
6179     }
6180 }
6181
6182 /* Check that the Nth argument of a function call (counting backwards
6183    from the end) is a (pointer)0.  The NARGS arguments are passed in the
6184    array ARGARRAY.  */
6185
6186 static void
6187 check_function_sentinel (tree attrs, int nargs, tree *argarray, tree typelist)
6188 {
6189   tree attr = lookup_attribute ("sentinel", attrs);
6190
6191   if (attr)
6192     {
6193       int len = 0;
6194       int pos = 0;
6195       tree sentinel;
6196
6197       /* Skip over the named arguments.  */
6198       while (typelist && len < nargs)
6199         {
6200           typelist = TREE_CHAIN (typelist);
6201           len++;
6202         }
6203
6204       if (TREE_VALUE (attr))
6205         {
6206           tree p = TREE_VALUE (TREE_VALUE (attr));
6207           pos = TREE_INT_CST_LOW (p);
6208         }
6209
6210       /* The sentinel must be one of the varargs, i.e.
6211          in position >= the number of fixed arguments.  */
6212       if ((nargs - 1 - pos) < len)
6213         {
6214           warning (OPT_Wformat,
6215                    "not enough variable arguments to fit a sentinel");
6216           return;
6217         }
6218
6219       /* Validate the sentinel.  */
6220       sentinel = argarray[nargs - 1 - pos];
6221       if ((!POINTER_TYPE_P (TREE_TYPE (sentinel))
6222            || !integer_zerop (sentinel))
6223           /* Although __null (in C++) is only an integer we allow it
6224              nevertheless, as we are guaranteed that it's exactly
6225              as wide as a pointer, and we don't want to force
6226              users to cast the NULL they have written there.
6227              We warn with -Wstrict-null-sentinel, though.  */
6228           && (warn_strict_null_sentinel || null_node != sentinel))
6229         warning (OPT_Wformat, "missing sentinel in function call");
6230     }
6231 }
6232
6233 /* Helper for check_function_nonnull; given a list of operands which
6234    must be non-null in ARGS, determine if operand PARAM_NUM should be
6235    checked.  */
6236
6237 static bool
6238 nonnull_check_p (tree args, unsigned HOST_WIDE_INT param_num)
6239 {
6240   unsigned HOST_WIDE_INT arg_num = 0;
6241
6242   for (; args; args = TREE_CHAIN (args))
6243     {
6244       bool found = get_nonnull_operand (TREE_VALUE (args), &arg_num);
6245
6246       gcc_assert (found);
6247
6248       if (arg_num == param_num)
6249         return true;
6250     }
6251   return false;
6252 }
6253
6254 /* Check that the function argument PARAM (which is operand number
6255    PARAM_NUM) is non-null.  This is called by check_function_nonnull
6256    via check_function_arguments_recurse.  */
6257
6258 static void
6259 check_nonnull_arg (void * ARG_UNUSED (ctx), tree param,
6260                    unsigned HOST_WIDE_INT param_num)
6261 {
6262   /* Just skip checking the argument if it's not a pointer.  This can
6263      happen if the "nonnull" attribute was given without an operand
6264      list (which means to check every pointer argument).  */
6265
6266   if (TREE_CODE (TREE_TYPE (param)) != POINTER_TYPE)
6267     return;
6268
6269   if (integer_zerop (param))
6270     warning (OPT_Wnonnull, "null argument where non-null required "
6271              "(argument %lu)", (unsigned long) param_num);
6272 }
6273
6274 /* Helper for nonnull attribute handling; fetch the operand number
6275    from the attribute argument list.  */
6276
6277 static bool
6278 get_nonnull_operand (tree arg_num_expr, unsigned HOST_WIDE_INT *valp)
6279 {
6280   /* Verify the arg number is a constant.  */
6281   if (TREE_CODE (arg_num_expr) != INTEGER_CST
6282       || TREE_INT_CST_HIGH (arg_num_expr) != 0)
6283     return false;
6284
6285   *valp = TREE_INT_CST_LOW (arg_num_expr);
6286   return true;
6287 }
6288
6289 /* Handle a "nothrow" attribute; arguments as in
6290    struct attribute_spec.handler.  */
6291
6292 static tree
6293 handle_nothrow_attribute (tree *node, tree name, tree ARG_UNUSED (args),
6294                           int ARG_UNUSED (flags), bool *no_add_attrs)
6295 {
6296   if (TREE_CODE (*node) == FUNCTION_DECL)
6297     TREE_NOTHROW (*node) = 1;
6298   /* ??? TODO: Support types.  */
6299   else
6300     {
6301       warning (OPT_Wattributes, "%qE attribute ignored", name);
6302       *no_add_attrs = true;
6303     }
6304
6305   return NULL_TREE;
6306 }
6307
6308 /* Handle a "cleanup" attribute; arguments as in
6309    struct attribute_spec.handler.  */
6310
6311 static tree
6312 handle_cleanup_attribute (tree *node, tree name, tree args,
6313                           int ARG_UNUSED (flags), bool *no_add_attrs)
6314 {
6315   tree decl = *node;
6316   tree cleanup_id, cleanup_decl;
6317
6318   /* ??? Could perhaps support cleanups on TREE_STATIC, much like we do
6319      for global destructors in C++.  This requires infrastructure that
6320      we don't have generically at the moment.  It's also not a feature
6321      we'd be missing too much, since we do have attribute constructor.  */
6322   if (TREE_CODE (decl) != VAR_DECL || TREE_STATIC (decl))
6323     {
6324       warning (OPT_Wattributes, "%qE attribute ignored", name);
6325       *no_add_attrs = true;
6326       return NULL_TREE;
6327     }
6328
6329   /* Verify that the argument is a function in scope.  */
6330   /* ??? We could support pointers to functions here as well, if
6331      that was considered desirable.  */
6332   cleanup_id = TREE_VALUE (args);
6333   if (TREE_CODE (cleanup_id) != IDENTIFIER_NODE)
6334     {
6335       error ("cleanup argument not an identifier");
6336       *no_add_attrs = true;
6337       return NULL_TREE;
6338     }
6339   cleanup_decl = lookup_name (cleanup_id);
6340   if (!cleanup_decl || TREE_CODE (cleanup_decl) != FUNCTION_DECL)
6341     {
6342       error ("cleanup argument not a function");
6343       *no_add_attrs = true;
6344       return NULL_TREE;
6345     }
6346
6347   /* That the function has proper type is checked with the
6348      eventual call to build_function_call.  */
6349
6350   return NULL_TREE;
6351 }
6352
6353 /* Handle a "warn_unused_result" attribute.  No special handling.  */
6354
6355 static tree
6356 handle_warn_unused_result_attribute (tree *node, tree name,
6357                                tree ARG_UNUSED (args),
6358                                int ARG_UNUSED (flags), bool *no_add_attrs)
6359 {
6360   /* Ignore the attribute for functions not returning any value.  */
6361   if (VOID_TYPE_P (TREE_TYPE (*node)))
6362     {
6363       warning (OPT_Wattributes, "%qE attribute ignored", name);
6364       *no_add_attrs = true;
6365     }
6366
6367   return NULL_TREE;
6368 }
6369
6370 /* Handle a "sentinel" attribute.  */
6371
6372 static tree
6373 handle_sentinel_attribute (tree *node, tree name, tree args,
6374                            int ARG_UNUSED (flags), bool *no_add_attrs)
6375 {
6376   tree params = TYPE_ARG_TYPES (*node);
6377
6378   if (!params)
6379     {
6380       warning (OPT_Wattributes,
6381                "%qE attribute requires prototypes with named arguments", name);
6382       *no_add_attrs = true;
6383     }
6384   else
6385     {
6386       while (TREE_CHAIN (params))
6387         params = TREE_CHAIN (params);
6388
6389       if (VOID_TYPE_P (TREE_VALUE (params)))
6390         {
6391           warning (OPT_Wattributes,
6392                    "%qE attribute only applies to variadic functions", name);
6393           *no_add_attrs = true;
6394         }
6395     }
6396
6397   if (args)
6398     {
6399       tree position = TREE_VALUE (args);
6400
6401       if (TREE_CODE (position) != INTEGER_CST)
6402         {
6403           warning (OPT_Wattributes,
6404                    "requested position is not an integer constant");
6405           *no_add_attrs = true;
6406         }
6407       else
6408         {
6409           if (tree_int_cst_lt (position, integer_zero_node))
6410             {
6411               warning (OPT_Wattributes,
6412                        "requested position is less than zero");
6413               *no_add_attrs = true;
6414             }
6415         }
6416     }
6417
6418   return NULL_TREE;
6419 }
6420
6421 /* Handle a "type_generic" attribute.  */
6422
6423 static tree
6424 handle_type_generic_attribute (tree *node, tree ARG_UNUSED (name),
6425                                tree ARG_UNUSED (args), int ARG_UNUSED (flags),
6426                                bool * ARG_UNUSED (no_add_attrs))
6427 {
6428   /* Ensure we have a function type, with no arguments.  */
6429   gcc_assert (TREE_CODE (*node) == FUNCTION_TYPE && ! TYPE_ARG_TYPES (*node));
6430
6431   return NULL_TREE;
6432 }
6433 \f
6434 /* Check for valid arguments being passed to a function.
6435    ATTRS is a list of attributes.  There are NARGS arguments in the array
6436    ARGARRAY.  TYPELIST is the list of argument types for the function.
6437  */
6438 void
6439 check_function_arguments (tree attrs, int nargs, tree *argarray, tree typelist)
6440 {
6441   /* Check for null being passed in a pointer argument that must be
6442      non-null.  We also need to do this if format checking is enabled.  */
6443
6444   if (warn_nonnull)
6445     check_function_nonnull (attrs, nargs, argarray);
6446
6447   /* Check for errors in format strings.  */
6448
6449   if (warn_format || warn_missing_format_attribute)
6450     check_function_format (attrs, nargs, argarray);
6451
6452   if (warn_format)
6453     check_function_sentinel (attrs, nargs, argarray, typelist);
6454 }
6455
6456 /* Generic argument checking recursion routine.  PARAM is the argument to
6457    be checked.  PARAM_NUM is the number of the argument.  CALLBACK is invoked
6458    once the argument is resolved.  CTX is context for the callback.  */
6459 void
6460 check_function_arguments_recurse (void (*callback)
6461                                   (void *, tree, unsigned HOST_WIDE_INT),
6462                                   void *ctx, tree param,
6463                                   unsigned HOST_WIDE_INT param_num)
6464 {
6465   if ((TREE_CODE (param) == NOP_EXPR || TREE_CODE (param) == CONVERT_EXPR)
6466       && (TYPE_PRECISION (TREE_TYPE (param))
6467           == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (param, 0)))))
6468     {
6469       /* Strip coercion.  */
6470       check_function_arguments_recurse (callback, ctx,
6471                                         TREE_OPERAND (param, 0), param_num);
6472       return;
6473     }
6474
6475   if (TREE_CODE (param) == CALL_EXPR)
6476     {
6477       tree type = TREE_TYPE (TREE_TYPE (CALL_EXPR_FN (param)));
6478       tree attrs;
6479       bool found_format_arg = false;
6480
6481       /* See if this is a call to a known internationalization function
6482          that modifies a format arg.  Such a function may have multiple
6483          format_arg attributes (for example, ngettext).  */
6484
6485       for (attrs = TYPE_ATTRIBUTES (type);
6486            attrs;
6487            attrs = TREE_CHAIN (attrs))
6488         if (is_attribute_p ("format_arg", TREE_PURPOSE (attrs)))
6489           {
6490             tree inner_arg;
6491             tree format_num_expr;
6492             int format_num;
6493             int i;
6494             call_expr_arg_iterator iter;
6495
6496             /* Extract the argument number, which was previously checked
6497                to be valid.  */
6498             format_num_expr = TREE_VALUE (TREE_VALUE (attrs));
6499
6500             gcc_assert (TREE_CODE (format_num_expr) == INTEGER_CST
6501                         && !TREE_INT_CST_HIGH (format_num_expr));
6502
6503             format_num = TREE_INT_CST_LOW (format_num_expr);
6504
6505             for (inner_arg = first_call_expr_arg (param, &iter), i = 1;
6506                  inner_arg != 0;
6507                  inner_arg = next_call_expr_arg (&iter), i++)
6508               if (i == format_num)
6509                 {
6510                   check_function_arguments_recurse (callback, ctx,
6511                                                     inner_arg, param_num);
6512                   found_format_arg = true;
6513                   break;
6514                 }
6515           }
6516
6517       /* If we found a format_arg attribute and did a recursive check,
6518          we are done with checking this argument.  Otherwise, we continue
6519          and this will be considered a non-literal.  */
6520       if (found_format_arg)
6521         return;
6522     }
6523
6524   if (TREE_CODE (param) == COND_EXPR)
6525     {
6526       /* Check both halves of the conditional expression.  */
6527       check_function_arguments_recurse (callback, ctx,
6528                                         TREE_OPERAND (param, 1), param_num);
6529       check_function_arguments_recurse (callback, ctx,
6530                                         TREE_OPERAND (param, 2), param_num);
6531       return;
6532     }
6533
6534   (*callback) (ctx, param, param_num);
6535 }
6536
6537 /* Function to help qsort sort FIELD_DECLs by name order.  */
6538
6539 int
6540 field_decl_cmp (const void *x_p, const void *y_p)
6541 {
6542   const tree *const x = (const tree *const) x_p;
6543   const tree *const y = (const tree *const) y_p;
6544
6545   if (DECL_NAME (*x) == DECL_NAME (*y))
6546     /* A nontype is "greater" than a type.  */
6547     return (TREE_CODE (*y) == TYPE_DECL) - (TREE_CODE (*x) == TYPE_DECL);
6548   if (DECL_NAME (*x) == NULL_TREE)
6549     return -1;
6550   if (DECL_NAME (*y) == NULL_TREE)
6551     return 1;
6552   if (DECL_NAME (*x) < DECL_NAME (*y))
6553     return -1;
6554   return 1;
6555 }
6556
6557 static struct {
6558   gt_pointer_operator new_value;
6559   void *cookie;
6560 } resort_data;
6561
6562 /* This routine compares two fields like field_decl_cmp but using the
6563 pointer operator in resort_data.  */
6564
6565 static int
6566 resort_field_decl_cmp (const void *x_p, const void *y_p)
6567 {
6568   const tree *const x = (const tree *const) x_p;
6569   const tree *const y = (const tree *const) y_p;
6570
6571   if (DECL_NAME (*x) == DECL_NAME (*y))
6572     /* A nontype is "greater" than a type.  */
6573     return (TREE_CODE (*y) == TYPE_DECL) - (TREE_CODE (*x) == TYPE_DECL);
6574   if (DECL_NAME (*x) == NULL_TREE)
6575     return -1;
6576   if (DECL_NAME (*y) == NULL_TREE)
6577     return 1;
6578   {
6579     tree d1 = DECL_NAME (*x);
6580     tree d2 = DECL_NAME (*y);
6581     resort_data.new_value (&d1, resort_data.cookie);
6582     resort_data.new_value (&d2, resort_data.cookie);
6583     if (d1 < d2)
6584       return -1;
6585   }
6586   return 1;
6587 }
6588
6589 /* Resort DECL_SORTED_FIELDS because pointers have been reordered.  */
6590
6591 void
6592 resort_sorted_fields (void *obj,
6593                       void * ARG_UNUSED (orig_obj),
6594                       gt_pointer_operator new_value,
6595                       void *cookie)
6596 {
6597   struct sorted_fields_type *sf = (struct sorted_fields_type *) obj;
6598   resort_data.new_value = new_value;
6599   resort_data.cookie = cookie;
6600   qsort (&sf->elts[0], sf->len, sizeof (tree),
6601          resort_field_decl_cmp);
6602 }
6603
6604 /* Subroutine of c_parse_error.
6605    Return the result of concatenating LHS and RHS. RHS is really
6606    a string literal, its first character is indicated by RHS_START and
6607    RHS_SIZE is its length (including the terminating NUL character).
6608
6609    The caller is responsible for deleting the returned pointer.  */
6610
6611 static char *
6612 catenate_strings (const char *lhs, const char *rhs_start, int rhs_size)
6613 {
6614   const int lhs_size = strlen (lhs);
6615   char *result = XNEWVEC (char, lhs_size + rhs_size);
6616   strncpy (result, lhs, lhs_size);
6617   strncpy (result + lhs_size, rhs_start, rhs_size);
6618   return result;
6619 }
6620
6621 /* Issue the error given by GMSGID, indicating that it occurred before
6622    TOKEN, which had the associated VALUE.  */
6623
6624 void
6625 c_parse_error (const char *gmsgid, enum cpp_ttype token, tree value)
6626 {
6627 #define catenate_messages(M1, M2) catenate_strings ((M1), (M2), sizeof (M2))
6628
6629   char *message = NULL;
6630
6631   if (token == CPP_EOF)
6632     message = catenate_messages (gmsgid, " at end of input");
6633   else if (token == CPP_CHAR || token == CPP_WCHAR)
6634     {
6635       unsigned int val = TREE_INT_CST_LOW (value);
6636       const char *const ell = (token == CPP_CHAR) ? "" : "L";
6637       if (val <= UCHAR_MAX && ISGRAPH (val))
6638         message = catenate_messages (gmsgid, " before %s'%c'");
6639       else
6640         message = catenate_messages (gmsgid, " before %s'\\x%x'");
6641
6642       error (message, ell, val);
6643       free (message);
6644       message = NULL;
6645     }
6646   else if (token == CPP_STRING || token == CPP_WSTRING)
6647     message = catenate_messages (gmsgid, " before string constant");
6648   else if (token == CPP_NUMBER)
6649     message = catenate_messages (gmsgid, " before numeric constant");
6650   else if (token == CPP_NAME)
6651     {
6652       message = catenate_messages (gmsgid, " before %qE");
6653       error (message, value);
6654       free (message);
6655       message = NULL;
6656     }
6657   else if (token == CPP_PRAGMA)
6658     message = catenate_messages (gmsgid, " before %<#pragma%>");
6659   else if (token == CPP_PRAGMA_EOL)
6660     message = catenate_messages (gmsgid, " before end of line");
6661   else if (token < N_TTYPES)
6662     {
6663       message = catenate_messages (gmsgid, " before %qs token");
6664       error (message, cpp_type2name (token));
6665       free (message);
6666       message = NULL;
6667     }
6668   else
6669     error (gmsgid);
6670
6671   if (message)
6672     {
6673       error (message);
6674       free (message);
6675     }
6676 #undef catenate_messages
6677 }
6678
6679 /* Walk a gimplified function and warn for functions whose return value is
6680    ignored and attribute((warn_unused_result)) is set.  This is done before
6681    inlining, so we don't have to worry about that.  */
6682
6683 void
6684 c_warn_unused_result (tree *top_p)
6685 {
6686   tree t = *top_p;
6687   tree_stmt_iterator i;
6688   tree fdecl, ftype;
6689
6690   switch (TREE_CODE (t))
6691     {
6692     case STATEMENT_LIST:
6693       for (i = tsi_start (*top_p); !tsi_end_p (i); tsi_next (&i))
6694         c_warn_unused_result (tsi_stmt_ptr (i));
6695       break;
6696
6697     case COND_EXPR:
6698       c_warn_unused_result (&COND_EXPR_THEN (t));
6699       c_warn_unused_result (&COND_EXPR_ELSE (t));
6700       break;
6701     case BIND_EXPR:
6702       c_warn_unused_result (&BIND_EXPR_BODY (t));
6703       break;
6704     case TRY_FINALLY_EXPR:
6705     case TRY_CATCH_EXPR:
6706       c_warn_unused_result (&TREE_OPERAND (t, 0));
6707       c_warn_unused_result (&TREE_OPERAND (t, 1));
6708       break;
6709     case CATCH_EXPR:
6710       c_warn_unused_result (&CATCH_BODY (t));
6711       break;
6712     case EH_FILTER_EXPR:
6713       c_warn_unused_result (&EH_FILTER_FAILURE (t));
6714       break;
6715
6716     case CALL_EXPR:
6717       if (TREE_USED (t))
6718         break;
6719
6720       /* This is a naked call, as opposed to a CALL_EXPR nested inside
6721          a MODIFY_EXPR.  All calls whose value is ignored should be
6722          represented like this.  Look for the attribute.  */
6723       fdecl = get_callee_fndecl (t);
6724       if (fdecl)
6725         ftype = TREE_TYPE (fdecl);
6726       else
6727         {
6728           ftype = TREE_TYPE (CALL_EXPR_FN (t));
6729           /* Look past pointer-to-function to the function type itself.  */
6730           ftype = TREE_TYPE (ftype);
6731         }
6732
6733       if (lookup_attribute ("warn_unused_result", TYPE_ATTRIBUTES (ftype)))
6734         {
6735           if (fdecl)
6736             warning (0, "%Hignoring return value of %qD, "
6737                      "declared with attribute warn_unused_result",
6738                      EXPR_LOCUS (t), fdecl);
6739           else
6740             warning (0, "%Hignoring return value of function "
6741                      "declared with attribute warn_unused_result",
6742                      EXPR_LOCUS (t));
6743         }
6744       break;
6745
6746     default:
6747       /* Not a container, not a call, or a call whose value is used.  */
6748       break;
6749     }
6750 }
6751
6752 /* Convert a character from the host to the target execution character
6753    set.  cpplib handles this, mostly.  */
6754
6755 HOST_WIDE_INT
6756 c_common_to_target_charset (HOST_WIDE_INT c)
6757 {
6758   /* Character constants in GCC proper are sign-extended under -fsigned-char,
6759      zero-extended under -fno-signed-char.  cpplib insists that characters
6760      and character constants are always unsigned.  Hence we must convert
6761      back and forth.  */
6762   cppchar_t uc = ((cppchar_t)c) & ((((cppchar_t)1) << CHAR_BIT)-1);
6763
6764   uc = cpp_host_to_exec_charset (parse_in, uc);
6765
6766   if (flag_signed_char)
6767     return ((HOST_WIDE_INT)uc) << (HOST_BITS_PER_WIDE_INT - CHAR_TYPE_SIZE)
6768                                >> (HOST_BITS_PER_WIDE_INT - CHAR_TYPE_SIZE);
6769   else
6770     return uc;
6771 }
6772
6773 /* Build the result of __builtin_offsetof.  EXPR is a nested sequence of
6774    component references, with STOP_REF, or alternatively an INDIRECT_REF of
6775    NULL, at the bottom; much like the traditional rendering of offsetof as a
6776    macro.  Returns the folded and properly cast result.  */
6777
6778 static tree
6779 fold_offsetof_1 (tree expr, tree stop_ref)
6780 {
6781   enum tree_code code = PLUS_EXPR;
6782   tree base, off, t;
6783
6784   if (expr == stop_ref && TREE_CODE (expr) != ERROR_MARK)
6785     return size_zero_node;
6786
6787   switch (TREE_CODE (expr))
6788     {
6789     case ERROR_MARK:
6790       return expr;
6791
6792     case VAR_DECL:
6793       error ("cannot apply %<offsetof%> to static data member %qD", expr);
6794       return error_mark_node;
6795
6796     case CALL_EXPR:
6797       error ("cannot apply %<offsetof%> when %<operator[]%> is overloaded");
6798       return error_mark_node;
6799
6800     case INTEGER_CST:
6801       gcc_assert (integer_zerop (expr));
6802       return size_zero_node;
6803
6804     case NOP_EXPR:
6805     case INDIRECT_REF:
6806       base = fold_offsetof_1 (TREE_OPERAND (expr, 0), stop_ref);
6807       gcc_assert (base == error_mark_node || base == size_zero_node);
6808       return base;
6809
6810     case COMPONENT_REF:
6811       base = fold_offsetof_1 (TREE_OPERAND (expr, 0), stop_ref);
6812       if (base == error_mark_node)
6813         return base;
6814
6815       t = TREE_OPERAND (expr, 1);
6816       if (DECL_C_BIT_FIELD (t))
6817         {
6818           error ("attempt to take address of bit-field structure "
6819                  "member %qD", t);
6820           return error_mark_node;
6821         }
6822       off = size_binop (PLUS_EXPR, DECL_FIELD_OFFSET (t),
6823                         size_int (tree_low_cst (DECL_FIELD_BIT_OFFSET (t), 1)
6824                                   / BITS_PER_UNIT));
6825       break;
6826
6827     case ARRAY_REF:
6828       base = fold_offsetof_1 (TREE_OPERAND (expr, 0), stop_ref);
6829       if (base == error_mark_node)
6830         return base;
6831
6832       t = TREE_OPERAND (expr, 1);
6833       if (TREE_CODE (t) == INTEGER_CST && tree_int_cst_sgn (t) < 0)
6834         {
6835           code = MINUS_EXPR;
6836           t = fold_build1 (NEGATE_EXPR, TREE_TYPE (t), t);
6837         }
6838       t = convert (sizetype, t);
6839       off = size_binop (MULT_EXPR, TYPE_SIZE_UNIT (TREE_TYPE (expr)), t);
6840       break;
6841
6842     case COMPOUND_EXPR:
6843       /* Handle static members of volatile structs.  */
6844       t = TREE_OPERAND (expr, 1);
6845       gcc_assert (TREE_CODE (t) == VAR_DECL);
6846       return fold_offsetof_1 (t, stop_ref);
6847
6848     default:
6849       gcc_unreachable ();
6850     }
6851
6852   return size_binop (code, base, off);
6853 }
6854
6855 tree
6856 fold_offsetof (tree expr, tree stop_ref)
6857 {
6858   /* Convert back from the internal sizetype to size_t.  */
6859   return convert (size_type_node, fold_offsetof_1 (expr, stop_ref));
6860 }
6861
6862 /* Print an error message for an invalid lvalue.  USE says
6863    how the lvalue is being used and so selects the error message.  */
6864
6865 void
6866 lvalue_error (enum lvalue_use use)
6867 {
6868   switch (use)
6869     {
6870     case lv_assign:
6871       error ("lvalue required as left operand of assignment");
6872       break;
6873     case lv_increment:
6874       error ("lvalue required as increment operand");
6875       break;
6876     case lv_decrement:
6877       error ("lvalue required as decrement operand");
6878       break;
6879     case lv_addressof:
6880       error ("lvalue required as unary %<&%> operand");
6881       break;
6882     case lv_asm:
6883       error ("lvalue required in asm statement");
6884       break;
6885     default:
6886       gcc_unreachable ();
6887     }
6888 }
6889 \f
6890 /* *PTYPE is an incomplete array.  Complete it with a domain based on
6891    INITIAL_VALUE.  If INITIAL_VALUE is not present, use 1 if DO_DEFAULT
6892    is true.  Return 0 if successful, 1 if INITIAL_VALUE can't be deciphered,
6893    2 if INITIAL_VALUE was NULL, and 3 if INITIAL_VALUE was empty.  */
6894
6895 int
6896 complete_array_type (tree *ptype, tree initial_value, bool do_default)
6897 {
6898   tree maxindex, type, main_type, elt, unqual_elt;
6899   int failure = 0, quals;
6900   hashval_t hashcode = 0;
6901
6902   maxindex = size_zero_node;
6903   if (initial_value)
6904     {
6905       if (TREE_CODE (initial_value) == STRING_CST)
6906         {
6907           int eltsize
6908             = int_size_in_bytes (TREE_TYPE (TREE_TYPE (initial_value)));
6909           maxindex = size_int (TREE_STRING_LENGTH (initial_value)/eltsize - 1);
6910         }
6911       else if (TREE_CODE (initial_value) == CONSTRUCTOR)
6912         {
6913           VEC(constructor_elt,gc) *v = CONSTRUCTOR_ELTS (initial_value);
6914
6915           if (VEC_empty (constructor_elt, v))
6916             {
6917               if (pedantic)
6918                 failure = 3;
6919               maxindex = integer_minus_one_node;
6920             }
6921           else
6922             {
6923               tree curindex;
6924               unsigned HOST_WIDE_INT cnt;
6925               constructor_elt *ce;
6926
6927               if (VEC_index (constructor_elt, v, 0)->index)
6928                 maxindex = fold_convert (sizetype,
6929                                          VEC_index (constructor_elt,
6930                                                     v, 0)->index);
6931               curindex = maxindex;
6932
6933               for (cnt = 1;
6934                    VEC_iterate (constructor_elt, v, cnt, ce);
6935                    cnt++)
6936                 {
6937                   if (ce->index)
6938                     curindex = fold_convert (sizetype, ce->index);
6939                   else
6940                     curindex = size_binop (PLUS_EXPR, curindex, size_one_node);
6941
6942                   if (tree_int_cst_lt (maxindex, curindex))
6943                     maxindex = curindex;
6944                 }
6945             }
6946         }
6947       else
6948         {
6949           /* Make an error message unless that happened already.  */
6950           if (initial_value != error_mark_node)
6951             failure = 1;
6952         }
6953     }
6954   else
6955     {
6956       failure = 2;
6957       if (!do_default)
6958         return failure;
6959     }
6960
6961   type = *ptype;
6962   elt = TREE_TYPE (type);
6963   quals = TYPE_QUALS (strip_array_types (elt));
6964   if (quals == 0)
6965     unqual_elt = elt;
6966   else
6967     unqual_elt = c_build_qualified_type (elt, TYPE_UNQUALIFIED);
6968
6969   /* Using build_distinct_type_copy and modifying things afterward instead
6970      of using build_array_type to create a new type preserves all of the
6971      TYPE_LANG_FLAG_? bits that the front end may have set.  */
6972   main_type = build_distinct_type_copy (TYPE_MAIN_VARIANT (type));
6973   TREE_TYPE (main_type) = unqual_elt;
6974   TYPE_DOMAIN (main_type) = build_index_type (maxindex);
6975   layout_type (main_type);
6976
6977   /* Make sure we have the canonical MAIN_TYPE. */
6978   hashcode = iterative_hash_object (TYPE_HASH (unqual_elt), hashcode);
6979   hashcode = iterative_hash_object (TYPE_HASH (TYPE_DOMAIN (main_type)),
6980                                     hashcode);
6981   main_type = type_hash_canon (hashcode, main_type);
6982
6983   /* Fix the canonical type.  */
6984   if (TYPE_STRUCTURAL_EQUALITY_P (TREE_TYPE (main_type))
6985       || TYPE_STRUCTURAL_EQUALITY_P (TYPE_DOMAIN (main_type)))
6986     SET_TYPE_STRUCTURAL_EQUALITY (main_type);
6987   else if (TYPE_CANONICAL (TREE_TYPE (main_type)) != TREE_TYPE (main_type)
6988            || (TYPE_CANONICAL (TYPE_DOMAIN (main_type))
6989                != TYPE_DOMAIN (main_type)))
6990     TYPE_CANONICAL (main_type)
6991       = build_array_type (TYPE_CANONICAL (TREE_TYPE (main_type)),
6992                           TYPE_CANONICAL (TYPE_DOMAIN (main_type)));
6993   else
6994     TYPE_CANONICAL (main_type) = main_type;
6995
6996   if (quals == 0)
6997     type = main_type;
6998   else
6999     type = c_build_qualified_type (main_type, quals);
7000
7001   if (COMPLETE_TYPE_P (type)
7002       && TREE_CODE (TYPE_SIZE_UNIT (type)) == INTEGER_CST
7003       && TREE_OVERFLOW (TYPE_SIZE_UNIT (type)))
7004     {
7005       error ("size of array is too large");
7006       /* If we proceed with the array type as it is, we'll eventually
7007          crash in tree_low_cst().  */
7008       type = error_mark_node;
7009     }
7010
7011   *ptype = type;
7012   return failure;
7013 }
7014
7015 \f
7016 /* Used to help initialize the builtin-types.def table.  When a type of
7017    the correct size doesn't exist, use error_mark_node instead of NULL.
7018    The later results in segfaults even when a decl using the type doesn't
7019    get invoked.  */
7020
7021 tree
7022 builtin_type_for_size (int size, bool unsignedp)
7023 {
7024   tree type = lang_hooks.types.type_for_size (size, unsignedp);
7025   return type ? type : error_mark_node;
7026 }
7027
7028 /* A helper function for resolve_overloaded_builtin in resolving the
7029    overloaded __sync_ builtins.  Returns a positive power of 2 if the
7030    first operand of PARAMS is a pointer to a supported data type.
7031    Returns 0 if an error is encountered.  */
7032
7033 static int
7034 sync_resolve_size (tree function, tree params)
7035 {
7036   tree type;
7037   int size;
7038
7039   if (params == NULL)
7040     {
7041       error ("too few arguments to function %qE", function);
7042       return 0;
7043     }
7044
7045   type = TREE_TYPE (TREE_VALUE (params));
7046   if (TREE_CODE (type) != POINTER_TYPE)
7047     goto incompatible;
7048
7049   type = TREE_TYPE (type);
7050   if (!INTEGRAL_TYPE_P (type) && !POINTER_TYPE_P (type))
7051     goto incompatible;
7052
7053   size = tree_low_cst (TYPE_SIZE_UNIT (type), 1);
7054   if (size == 1 || size == 2 || size == 4 || size == 8 || size == 16)
7055     return size;
7056
7057  incompatible:
7058   error ("incompatible type for argument %d of %qE", 1, function);
7059   return 0;
7060 }
7061
7062 /* A helper function for resolve_overloaded_builtin.  Adds casts to
7063    PARAMS to make arguments match up with those of FUNCTION.  Drops
7064    the variadic arguments at the end.  Returns false if some error
7065    was encountered; true on success.  */
7066
7067 static bool
7068 sync_resolve_params (tree orig_function, tree function, tree params)
7069 {
7070   tree arg_types = TYPE_ARG_TYPES (TREE_TYPE (function));
7071   tree ptype;
7072   int number;
7073
7074   /* We've declared the implementation functions to use "volatile void *"
7075      as the pointer parameter, so we shouldn't get any complaints from the
7076      call to check_function_arguments what ever type the user used.  */
7077   arg_types = TREE_CHAIN (arg_types);
7078   ptype = TREE_TYPE (TREE_TYPE (TREE_VALUE (params)));
7079   number = 2;
7080
7081   /* For the rest of the values, we need to cast these to FTYPE, so that we
7082      don't get warnings for passing pointer types, etc.  */
7083   while (arg_types != void_list_node)
7084     {
7085       tree val;
7086
7087       params = TREE_CHAIN (params);
7088       if (params == NULL)
7089         {
7090           error ("too few arguments to function %qE", orig_function);
7091           return false;
7092         }
7093
7094       /* ??? Ideally for the first conversion we'd use convert_for_assignment
7095          so that we get warnings for anything that doesn't match the pointer
7096          type.  This isn't portable across the C and C++ front ends atm.  */
7097       val = TREE_VALUE (params);
7098       val = convert (ptype, val);
7099       val = convert (TREE_VALUE (arg_types), val);
7100       TREE_VALUE (params) = val;
7101
7102       arg_types = TREE_CHAIN (arg_types);
7103       number++;
7104     }
7105
7106   /* The definition of these primitives is variadic, with the remaining
7107      being "an optional list of variables protected by the memory barrier".
7108      No clue what that's supposed to mean, precisely, but we consider all
7109      call-clobbered variables to be protected so we're safe.  */
7110   TREE_CHAIN (params) = NULL;
7111
7112   return true;
7113 }
7114
7115 /* A helper function for resolve_overloaded_builtin.  Adds a cast to
7116    RESULT to make it match the type of the first pointer argument in
7117    PARAMS.  */
7118
7119 static tree
7120 sync_resolve_return (tree params, tree result)
7121 {
7122   tree ptype = TREE_TYPE (TREE_TYPE (TREE_VALUE (params)));
7123   ptype = TYPE_MAIN_VARIANT (ptype);
7124   return convert (ptype, result);
7125 }
7126
7127 /* Some builtin functions are placeholders for other expressions.  This
7128    function should be called immediately after parsing the call expression
7129    before surrounding code has committed to the type of the expression.
7130
7131    FUNCTION is the DECL that has been invoked; it is known to be a builtin.
7132    PARAMS is the argument list for the call.  The return value is non-null
7133    when expansion is complete, and null if normal processing should
7134    continue.  */
7135
7136 tree
7137 resolve_overloaded_builtin (tree function, tree params)
7138 {
7139   enum built_in_function orig_code = DECL_FUNCTION_CODE (function);
7140   switch (DECL_BUILT_IN_CLASS (function))
7141     {
7142     case BUILT_IN_NORMAL:
7143       break;
7144     case BUILT_IN_MD:
7145       if (targetm.resolve_overloaded_builtin)
7146         return targetm.resolve_overloaded_builtin (function, params);
7147       else
7148         return NULL_TREE;
7149     default:
7150       return NULL_TREE;
7151     }
7152
7153   /* Handle BUILT_IN_NORMAL here.  */
7154   switch (orig_code)
7155     {
7156     case BUILT_IN_FETCH_AND_ADD_N:
7157     case BUILT_IN_FETCH_AND_SUB_N:
7158     case BUILT_IN_FETCH_AND_OR_N:
7159     case BUILT_IN_FETCH_AND_AND_N:
7160     case BUILT_IN_FETCH_AND_XOR_N:
7161     case BUILT_IN_FETCH_AND_NAND_N:
7162     case BUILT_IN_ADD_AND_FETCH_N:
7163     case BUILT_IN_SUB_AND_FETCH_N:
7164     case BUILT_IN_OR_AND_FETCH_N:
7165     case BUILT_IN_AND_AND_FETCH_N:
7166     case BUILT_IN_XOR_AND_FETCH_N:
7167     case BUILT_IN_NAND_AND_FETCH_N:
7168     case BUILT_IN_BOOL_COMPARE_AND_SWAP_N:
7169     case BUILT_IN_VAL_COMPARE_AND_SWAP_N:
7170     case BUILT_IN_LOCK_TEST_AND_SET_N:
7171     case BUILT_IN_LOCK_RELEASE_N:
7172       {
7173         int n = sync_resolve_size (function, params);
7174         tree new_function, result;
7175
7176         if (n == 0)
7177           return error_mark_node;
7178
7179         new_function = built_in_decls[orig_code + exact_log2 (n) + 1];
7180         if (!sync_resolve_params (function, new_function, params))
7181           return error_mark_node;
7182
7183         result = build_function_call (new_function, params);
7184         if (orig_code != BUILT_IN_BOOL_COMPARE_AND_SWAP_N
7185             && orig_code != BUILT_IN_LOCK_RELEASE_N)
7186           result = sync_resolve_return (params, result);
7187
7188         return result;
7189       }
7190
7191     default:
7192       return NULL_TREE;
7193     }
7194 }
7195
7196 /* Ignoring their sign, return true if two scalar types are the same.  */
7197 bool
7198 same_scalar_type_ignoring_signedness (tree t1, tree t2)
7199 {
7200   enum tree_code c1 = TREE_CODE (t1), c2 = TREE_CODE (t2);
7201
7202   gcc_assert ((c1 == INTEGER_TYPE || c1 == REAL_TYPE || c1 == FIXED_POINT_TYPE)
7203               && (c2 == INTEGER_TYPE || c2 == REAL_TYPE
7204                   || c2 == FIXED_POINT_TYPE));
7205
7206   /* Equality works here because c_common_signed_type uses
7207      TYPE_MAIN_VARIANT.  */
7208   return c_common_signed_type (t1)
7209     == c_common_signed_type (t2);
7210 }
7211
7212 /* Check for missing format attributes on function pointers.  LTYPE is
7213    the new type or left-hand side type.  RTYPE is the old type or
7214    right-hand side type.  Returns TRUE if LTYPE is missing the desired
7215    attribute.  */
7216
7217 bool
7218 check_missing_format_attribute (tree ltype, tree rtype)
7219 {
7220   tree const ttr = TREE_TYPE (rtype), ttl = TREE_TYPE (ltype);
7221   tree ra;
7222
7223   for (ra = TYPE_ATTRIBUTES (ttr); ra; ra = TREE_CHAIN (ra))
7224     if (is_attribute_p ("format", TREE_PURPOSE (ra)))
7225       break;
7226   if (ra)
7227     {
7228       tree la;
7229       for (la = TYPE_ATTRIBUTES (ttl); la; la = TREE_CHAIN (la))
7230         if (is_attribute_p ("format", TREE_PURPOSE (la)))
7231           break;
7232       return !la;
7233     }
7234   else
7235     return false;
7236 }
7237
7238 /* Subscripting with type char is likely to lose on a machine where
7239    chars are signed.  So warn on any machine, but optionally.  Don't
7240    warn for unsigned char since that type is safe.  Don't warn for
7241    signed char because anyone who uses that must have done so
7242    deliberately. Furthermore, we reduce the false positive load by
7243    warning only for non-constant value of type char.  */
7244
7245 void
7246 warn_array_subscript_with_type_char (tree index)
7247 {
7248   if (TYPE_MAIN_VARIANT (TREE_TYPE (index)) == char_type_node
7249       && TREE_CODE (index) != INTEGER_CST)
7250     warning (OPT_Wchar_subscripts, "array subscript has type %<char%>");
7251 }
7252
7253 /* Implement -Wparentheses for the unexpected C precedence rules, to
7254    cover cases like x + y << z which readers are likely to
7255    misinterpret.  We have seen an expression in which CODE is a binary
7256    operator used to combine expressions headed by CODE_LEFT and
7257    CODE_RIGHT.  CODE_LEFT and CODE_RIGHT may be ERROR_MARK, which
7258    means that that side of the expression was not formed using a
7259    binary operator, or it was enclosed in parentheses.  */
7260
7261 void
7262 warn_about_parentheses (enum tree_code code, enum tree_code code_left,
7263                         enum tree_code code_right)
7264 {
7265   if (!warn_parentheses)
7266     return;
7267
7268   if (code == LSHIFT_EXPR || code == RSHIFT_EXPR)
7269     {
7270       if (code_left == PLUS_EXPR || code_left == MINUS_EXPR
7271           || code_right == PLUS_EXPR || code_right == MINUS_EXPR)
7272         warning (OPT_Wparentheses,
7273                  "suggest parentheses around + or - inside shift");
7274     }
7275
7276   if (code == TRUTH_ORIF_EXPR)
7277     {
7278       if (code_left == TRUTH_ANDIF_EXPR
7279           || code_right == TRUTH_ANDIF_EXPR)
7280         warning (OPT_Wparentheses,
7281                  "suggest parentheses around && within ||");
7282     }
7283
7284   if (code == BIT_IOR_EXPR)
7285     {
7286       if (code_left == BIT_AND_EXPR || code_left == BIT_XOR_EXPR
7287           || code_left == PLUS_EXPR || code_left == MINUS_EXPR
7288           || code_right == BIT_AND_EXPR || code_right == BIT_XOR_EXPR
7289           || code_right == PLUS_EXPR || code_right == MINUS_EXPR)
7290         warning (OPT_Wparentheses,
7291                  "suggest parentheses around arithmetic in operand of |");
7292       /* Check cases like x|y==z */
7293       if (TREE_CODE_CLASS (code_left) == tcc_comparison
7294           || TREE_CODE_CLASS (code_right) == tcc_comparison)
7295         warning (OPT_Wparentheses,
7296                  "suggest parentheses around comparison in operand of |");
7297     }
7298
7299   if (code == BIT_XOR_EXPR)
7300     {
7301       if (code_left == BIT_AND_EXPR
7302           || code_left == PLUS_EXPR || code_left == MINUS_EXPR
7303           || code_right == BIT_AND_EXPR
7304           || code_right == PLUS_EXPR || code_right == MINUS_EXPR)
7305         warning (OPT_Wparentheses,
7306                  "suggest parentheses around arithmetic in operand of ^");
7307       /* Check cases like x^y==z */
7308       if (TREE_CODE_CLASS (code_left) == tcc_comparison
7309           || TREE_CODE_CLASS (code_right) == tcc_comparison)
7310         warning (OPT_Wparentheses,
7311                  "suggest parentheses around comparison in operand of ^");
7312     }
7313
7314   if (code == BIT_AND_EXPR)
7315     {
7316       if (code_left == PLUS_EXPR || code_left == MINUS_EXPR
7317           || code_right == PLUS_EXPR || code_right == MINUS_EXPR)
7318         warning (OPT_Wparentheses,
7319                  "suggest parentheses around + or - in operand of &");
7320       /* Check cases like x&y==z */
7321       if (TREE_CODE_CLASS (code_left) == tcc_comparison
7322           || TREE_CODE_CLASS (code_right) == tcc_comparison)
7323         warning (OPT_Wparentheses,
7324                  "suggest parentheses around comparison in operand of &");
7325     }
7326
7327   if (code == EQ_EXPR || code == NE_EXPR)
7328     {
7329       if (TREE_CODE_CLASS (code_left) == tcc_comparison
7330           || TREE_CODE_CLASS (code_right) == tcc_comparison)
7331         warning (OPT_Wparentheses,
7332                  "suggest parentheses around comparison in operand of %s",
7333                  code == EQ_EXPR ? "==" : "!=");
7334     }
7335   else if (TREE_CODE_CLASS (code) == tcc_comparison)
7336     {
7337       if ((TREE_CODE_CLASS (code_left) == tcc_comparison
7338            && code_left != NE_EXPR && code_left != EQ_EXPR)
7339           || (TREE_CODE_CLASS (code_right) == tcc_comparison
7340               && code_right != NE_EXPR && code_right != EQ_EXPR))
7341         warning (OPT_Wparentheses, "comparisons like X<=Y<=Z do not "
7342                  "have their mathematical meaning");
7343     }
7344 }
7345
7346 /* If LABEL (a LABEL_DECL) has not been used, issue a warning.  */
7347
7348 void
7349 warn_for_unused_label (tree label)
7350 {
7351   if (!TREE_USED (label))
7352     {
7353       if (DECL_INITIAL (label))
7354         warning (OPT_Wunused_label, "label %q+D defined but not used", label);
7355       else
7356         warning (OPT_Wunused_label, "label %q+D declared but not defined", label);
7357     }
7358 }
7359
7360 #ifndef TARGET_HAS_TARGETCM
7361 struct gcc_targetcm targetcm = TARGETCM_INITIALIZER;
7362 #endif
7363
7364 /* Warn for division by zero according to the value of DIVISOR.  */
7365
7366 void
7367 warn_for_div_by_zero (tree divisor)
7368 {
7369   /* If DIVISOR is zero, and has integral or fixed-point type, issue a warning
7370      about division by zero.  Do not issue a warning if DIVISOR has a
7371      floating-point type, since we consider 0.0/0.0 a valid way of
7372      generating a NaN.  */
7373   if (skip_evaluation == 0
7374       && (integer_zerop (divisor) || fixed_zerop (divisor)))
7375     warning (OPT_Wdiv_by_zero, "division by zero");
7376 }
7377
7378 #include "gt-c-common.h"