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 Free Software Foundation, Inc.
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify it under
   8 the terms of the GNU General Public License as published by the Free
   9 Software Foundation; either version 2, or (at your option) any later
  10 version.
  11
  12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15 for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GCC; see the file COPYING.  If not, write to the Free
  19 Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
  20 02110-1301, USA.  */
  21
  22 #include "config.h"
  23 #include "system.h"
  24 #include "coretypes.h"
  25 #include "tm.h"
  26 #include "intl.h"
  27 #include "tree.h"
  28 #include "flags.h"
  29 #include "output.h"
  30 #include "c-pragma.h"
  31 #include "rtl.h"
  32 #include "ggc.h"
  33 #include "varray.h"
  34 #include "expr.h"
  35 #include "c-common.h"
  36 #include "diagnostic.h"
  37 #include "tm_p.h"
  38 #include "obstack.h"
  39 #include "cpplib.h"
  40 #include "target.h"
  41 #include "langhooks.h"
  42 #include "tree-inline.h"
  43 #include "c-tree.h"
  44 #include "toplev.h"
  45 #include "tree-iterator.h"
  46 #include "hashtab.h"
  47 #include "tree-mudflap.h"
  48 #include "opts.h"
  49 #include "real.h"
  50 #include "cgraph.h"
  51 #include "target-def.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 /* Nonzero if we want to allow the use of experimental features that
 410    are likely to become part of C++0x. */
 411
 412 int flag_cpp0x = 0;
 413
 414 /* Nonzero if we want the new ISO rules for pushing a new scope for `for'
 415    initialization variables.
 416    0: Old rules, set by -fno-for-scope.
 417    2: New ISO rules, set by -ffor-scope.
 418    1: Try to implement new ISO rules, but with backup compatibility
 419    (and warnings).  This is the default, for now.  */
 420
 421 int flag_new_for_scope = 1;
 422
 423 /* Nonzero if we want to emit defined symbols with common-like linkage as
 424    weak symbols where possible, in order to conform to C++ semantics.
 425    Otherwise, emit them as local symbols.  */
 426
 427 int flag_weak = 1;
 428
 429 /* 0 means we want the preprocessor to not emit line directives for
 430    the current working directory.  1 means we want it to do it.  -1
 431    means we should decide depending on whether debugging information
 432    is being emitted or not.  */
 433
 434 int flag_working_directory = -1;
 435
 436 /* Nonzero to use __cxa_atexit, rather than atexit, to register
 437    destructors for local statics and global objects.  '2' means it has been
 438    set nonzero as a default, not by a command-line flag.  */
 439
 440 int flag_use_cxa_atexit = DEFAULT_USE_CXA_ATEXIT;
 441
 442 /* Nonzero to use __cxa_get_exception_ptr in C++ exception-handling
 443    code.  '2' means it has not been set explicitly on the command line.  */
 444
 445 int flag_use_cxa_get_exception_ptr = 2;
 446
 447 /* Nonzero means make the default pedwarns warnings instead of errors.
 448    The value of this flag is ignored if -pedantic is specified.  */
 449
 450 int flag_permissive;
 451
 452 /* Nonzero means to implement standard semantics for exception
 453    specifications, calling unexpected if an exception is thrown that
 454    doesn't match the specification.  Zero means to treat them as
 455    assertions and optimize accordingly, but not check them.  */
 456
 457 int flag_enforce_eh_specs = 1;
 458
 459 /* Nonzero means to generate thread-safe code for initializing local
 460    statics.  */
 461
 462 int flag_threadsafe_statics = 1;
 463
 464 /* Nonzero means warn about implicit declarations.  */
 465
 466 int warn_implicit = 1;
 467
 468 /* Maximum template instantiation depth.  This limit is rather
 469    arbitrary, but it exists to limit the time it takes to notice
 470    infinite template instantiations.  */
 471
 472 int max_tinst_depth = 500;
 473
 474
 475
 476 /* The elements of `ridpointers' are identifier nodes for the reserved
 477    type names and storage classes.  It is indexed by a RID_... value.  */
 478 tree *ridpointers;
 479
 480 tree (*make_fname_decl) (tree, int);
 481
 482 /* Nonzero means the expression being parsed will never be evaluated.
 483    This is a count, since unevaluated expressions can nest.  */
 484 int skip_evaluation;
 485
 486 /* Information about how a function name is generated.  */
 487 struct fname_var_t
 488 {
 489   tree *const decl;     /* pointer to the VAR_DECL.  */
 490   const unsigned rid;   /* RID number for the identifier.  */
 491   const int pretty;     /* How pretty is it? */
 492 };
 493
 494 /* The three ways of getting then name of the current function.  */
 495
 496 const struct fname_var_t fname_vars[] =
 497 {
 498   /* C99 compliant __func__, must be first.  */
 499   {&c99_function_name_decl_node, RID_C99_FUNCTION_NAME, 0},
 500   /* GCC __FUNCTION__ compliant.  */
 501   {&function_name_decl_node, RID_FUNCTION_NAME, 0},
 502   /* GCC __PRETTY_FUNCTION__ compliant.  */
 503   {&pretty_function_name_decl_node, RID_PRETTY_FUNCTION_NAME, 1},
 504   {NULL, 0, 0},
 505 };
 506
 507 static tree check_case_value (tree);
 508 static bool check_case_bounds (tree, tree, tree *, tree *);
 509
 510 static tree handle_packed_attribute (tree *, tree, tree, int, bool *);
 511 static tree handle_nocommon_attribute (tree *, tree, tree, int, bool *);
 512 static tree handle_common_attribute (tree *, tree, tree, int, bool *);
 513 static tree handle_noreturn_attribute (tree *, tree, tree, int, bool *);
 514 static tree handle_hot_attribute (tree *, tree, tree, int, bool *);
 515 static tree handle_cold_attribute (tree *, tree, tree, int, bool *);
 516 static tree handle_noinline_attribute (tree *, tree, tree, int, bool *);
 517 static tree handle_always_inline_attribute (tree *, tree, tree, int,
 518                                             bool *);
 519 static tree handle_gnu_inline_attribute (tree *, tree, tree, int,
 520                                          bool *);
 521 static tree handle_flatten_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_alloc_size_attribute (tree *, tree, tree, int, bool *);
 560
 561 static void check_function_nonnull (tree, int, tree *);
 562 static void check_nonnull_arg (void *, tree, unsigned HOST_WIDE_INT);
 563 static bool nonnull_check_p (tree, unsigned HOST_WIDE_INT);
 564 static bool get_nonnull_operand (tree, unsigned HOST_WIDE_INT *);
 565 static int resort_field_decl_cmp (const void *, const void *);
 566
 567 /* Table of machine-independent attributes common to all C-like languages.  */
 568 const struct attribute_spec c_common_attribute_table[] =
 569 {
 570   /* { name, min_len, max_len, decl_req, type_req, fn_type_req, handler } */
 571   { "packed",                 0, 0, false, false, false,
 572                               handle_packed_attribute },
 573   { "nocommon",               0, 0, true,  false, false,
 574                               handle_nocommon_attribute },
 575   { "common",                 0, 0, true,  false, false,
 576                               handle_common_attribute },
 577   /* FIXME: logically, noreturn attributes should be listed as
 578      "false, true, true" and apply to function types.  But implementing this
 579      would require all the places in the compiler that use TREE_THIS_VOLATILE
 580      on a decl to identify non-returning functions to be located and fixed
 581      to check the function type instead.  */
 582   { "noreturn",               0, 0, true,  false, false,
 583                               handle_noreturn_attribute },
 584   { "volatile",               0, 0, true,  false, false,
 585                               handle_noreturn_attribute },
 586   { "noinline",               0, 0, true,  false, false,
 587                               handle_noinline_attribute },
 588   { "always_inline",          0, 0, true,  false, false,
 589                               handle_always_inline_attribute },
 590   { "gnu_inline",             0, 0, true,  false, false,
 591                               handle_gnu_inline_attribute },
 592   { "flatten",                0, 0, true,  false, false,
 593                               handle_flatten_attribute },
 594   { "used",                   0, 0, true,  false, false,
 595                               handle_used_attribute },
 596   { "unused",                 0, 0, false, false, false,
 597                               handle_unused_attribute },
 598   { "externally_visible",     0, 0, true,  false, false,
 599                               handle_externally_visible_attribute },
 600   /* The same comments as for noreturn attributes apply to const ones.  */
 601   { "const",                  0, 0, true,  false, false,
 602                               handle_const_attribute },
 603   { "transparent_union",      0, 0, false, false, false,
 604                               handle_transparent_union_attribute },
 605   { "constructor",            0, 1, true,  false, false,
 606                               handle_constructor_attribute },
 607   { "destructor",             0, 1, true,  false, false,
 608                               handle_destructor_attribute },
 609   { "mode",                   1, 1, false,  true, false,
 610                               handle_mode_attribute },
 611   { "section",                1, 1, true,  false, false,
 612                               handle_section_attribute },
 613   { "aligned",                0, 1, false, false, false,
 614                               handle_aligned_attribute },
 615   { "weak",                   0, 0, true,  false, false,
 616                               handle_weak_attribute },
 617   { "alias",                  1, 1, true,  false, false,
 618                               handle_alias_attribute },
 619   { "weakref",                0, 1, true,  false, false,
 620                               handle_weakref_attribute },
 621   { "no_instrument_function", 0, 0, true,  false, false,
 622                               handle_no_instrument_function_attribute },
 623   { "malloc",                 0, 0, true,  false, false,
 624                               handle_malloc_attribute },
 625   { "returns_twice",          0, 0, true,  false, false,
 626                               handle_returns_twice_attribute },
 627   { "no_stack_limit",         0, 0, true,  false, false,
 628                               handle_no_limit_stack_attribute },
 629   { "pure",                   0, 0, true,  false, false,
 630                               handle_pure_attribute },
 631   /* For internal use (marking of builtins) only.  The name contains space
 632      to prevent its usage in source code.  */
 633   { "no vops",                0, 0, true,  false, false,
 634                               handle_novops_attribute },
 635   { "deprecated",             0, 0, false, false, false,
 636                               handle_deprecated_attribute },
 637   { "vector_size",            1, 1, false, true, false,
 638                               handle_vector_size_attribute },
 639   { "visibility",             1, 1, false, false, false,
 640                               handle_visibility_attribute },
 641   { "tls_model",              1, 1, true,  false, false,
 642                               handle_tls_model_attribute },
 643   { "nonnull",                0, -1, false, true, true,
 644                               handle_nonnull_attribute },
 645   { "nothrow",                0, 0, true,  false, false,
 646                               handle_nothrow_attribute },
 647   { "may_alias",              0, 0, false, true, false, NULL },
 648   { "cleanup",                1, 1, true, false, false,
 649                               handle_cleanup_attribute },
 650   { "warn_unused_result",     0, 0, false, true, true,
 651                               handle_warn_unused_result_attribute },
 652   { "sentinel",               0, 1, false, true, true,
 653                               handle_sentinel_attribute },
 654   { "alloc_size",             1, 2, false, true, true,
 655                               handle_alloc_size_attribute },
 656   { "cold",                   0, 0, true,  false, false,
 657                               handle_cold_attribute },
 658   { "hot",                    0, 0, true,  false, false,
 659                               handle_hot_attribute },
 660   { NULL,                     0, 0, false, false, false, NULL }
 661 };
 662
 663 /* Give the specifications for the format attributes, used by C and all
 664    descendants.  */
 665
 666 const struct attribute_spec c_common_format_attribute_table[] =
 667 {
 668   /* { name, min_len, max_len, decl_req, type_req, fn_type_req, handler } */
 669   { "format",                 3, 3, false, true,  true,
 670                               handle_format_attribute },
 671   { "format_arg",             1, 1, false, true,  true,
 672                               handle_format_arg_attribute },
 673   { NULL,                     0, 0, false, false, false, NULL }
 674 };
 675
 676 /* Push current bindings for the function name VAR_DECLS.  */
 677
 678 void
 679 start_fname_decls (void)
 680 {
 681   unsigned ix;
 682   tree saved = NULL_TREE;
 683
 684   for (ix = 0; fname_vars[ix].decl; ix++)
 685     {
 686       tree decl = *fname_vars[ix].decl;
 687
 688       if (decl)
 689         {
 690           saved = tree_cons (decl, build_int_cst (NULL_TREE, ix), saved);
 691           *fname_vars[ix].decl = NULL_TREE;
 692         }
 693     }
 694   if (saved || saved_function_name_decls)
 695     /* Normally they'll have been NULL, so only push if we've got a
 696        stack, or they are non-NULL.  */
 697     saved_function_name_decls = tree_cons (saved, NULL_TREE,
 698                                            saved_function_name_decls);
 699 }
 700
 701 /* Finish up the current bindings, adding them into the current function's
 702    statement tree.  This must be done _before_ finish_stmt_tree is called.
 703    If there is no current function, we must be at file scope and no statements
 704    are involved. Pop the previous bindings.  */
 705
 706 void
 707 finish_fname_decls (void)
 708 {
 709   unsigned ix;
 710   tree stmts = NULL_TREE;
 711   tree stack = saved_function_name_decls;
 712
 713   for (; stack && TREE_VALUE (stack); stack = TREE_CHAIN (stack))
 714     append_to_statement_list (TREE_VALUE (stack), &stmts);
 715
 716   if (stmts)
 717     {
 718       tree *bodyp = &DECL_SAVED_TREE (current_function_decl);
 719
 720       if (TREE_CODE (*bodyp) == BIND_EXPR)
 721         bodyp = &BIND_EXPR_BODY (*bodyp);
 722
 723       append_to_statement_list_force (*bodyp, &stmts);
 724       *bodyp = stmts;
 725     }
 726
 727   for (ix = 0; fname_vars[ix].decl; ix++)
 728     *fname_vars[ix].decl = NULL_TREE;
 729
 730   if (stack)
 731     {
 732       /* We had saved values, restore them.  */
 733       tree saved;
 734
 735       for (saved = TREE_PURPOSE (stack); saved; saved = TREE_CHAIN (saved))
 736         {
 737           tree decl = TREE_PURPOSE (saved);
 738           unsigned ix = TREE_INT_CST_LOW (TREE_VALUE (saved));
 739
 740           *fname_vars[ix].decl = decl;
 741         }
 742       stack = TREE_CHAIN (stack);
 743     }
 744   saved_function_name_decls = stack;
 745 }
 746
 747 /* Return the text name of the current function, suitably prettified
 748    by PRETTY_P.  Return string must be freed by caller.  */
 749
 750 const char *
 751 fname_as_string (int pretty_p)
 752 {
 753   const char *name = "top level";
 754   char *namep;
 755   int vrb = 2;
 756
 757   if (!pretty_p)
 758     {
 759       name = "";
 760       vrb = 0;
 761     }
 762
 763   if (current_function_decl)
 764     name = lang_hooks.decl_printable_name (current_function_decl, vrb);
 765
 766   if (c_lex_string_translate)
 767     {
 768       int len = strlen (name) + 3; /* Two for '"'s.  One for NULL.  */
 769       cpp_string cstr = { 0, 0 }, strname;
 770
 771       namep = XNEWVEC (char, len);
 772       snprintf (namep, len, "\"%s\"", name);
 773       strname.text = (unsigned char *) namep;
 774       strname.len = len - 1;
 775
 776       if (cpp_interpret_string (parse_in, &strname, 1, &cstr, false))
 777         {
 778           XDELETEVEC (namep);
 779           return (char *) cstr.text;
 780         }
 781     }
 782   else
 783     namep = xstrdup (name);
 784
 785   return namep;
 786 }
 787
 788 /* Expand DECL if it declares an entity not handled by the
 789    common code.  */
 790
 791 int
 792 c_expand_decl (tree decl)
 793 {
 794   if (TREE_CODE (decl) == VAR_DECL && !TREE_STATIC (decl))
 795     {
 796       /* Let the back-end know about this variable.  */
 797       if (!anon_aggr_type_p (TREE_TYPE (decl)))
 798         emit_local_var (decl);
 799       else
 800         expand_anon_union_decl (decl, NULL_TREE,
 801                                 DECL_ANON_UNION_ELEMS (decl));
 802     }
 803   else
 804     return 0;
 805
 806   return 1;
 807 }
 808
 809
 810 /* Return the VAR_DECL for a const char array naming the current
 811    function. If the VAR_DECL has not yet been created, create it
 812    now. RID indicates how it should be formatted and IDENTIFIER_NODE
 813    ID is its name (unfortunately C and C++ hold the RID values of
 814    keywords in different places, so we can't derive RID from ID in
 815    this language independent code.  */
 816
 817 tree
 818 fname_decl (unsigned int rid, tree id)
 819 {
 820   unsigned ix;
 821   tree decl = NULL_TREE;
 822
 823   for (ix = 0; fname_vars[ix].decl; ix++)
 824     if (fname_vars[ix].rid == rid)
 825       break;
 826
 827   decl = *fname_vars[ix].decl;
 828   if (!decl)
 829     {
 830       /* If a tree is built here, it would normally have the lineno of
 831          the current statement.  Later this tree will be moved to the
 832          beginning of the function and this line number will be wrong.
 833          To avoid this problem set the lineno to 0 here; that prevents
 834          it from appearing in the RTL.  */
 835       tree stmts;
 836       location_t saved_location = input_location;
 837 #ifdef USE_MAPPED_LOCATION
 838       input_location = UNKNOWN_LOCATION;
 839 #else
 840       input_line = 0;
 841 #endif
 842
 843       stmts = push_stmt_list ();
 844       decl = (*make_fname_decl) (id, fname_vars[ix].pretty);
 845       stmts = pop_stmt_list (stmts);
 846       if (!IS_EMPTY_STMT (stmts))
 847         saved_function_name_decls
 848           = tree_cons (decl, stmts, saved_function_name_decls);
 849       *fname_vars[ix].decl = decl;
 850       input_location = saved_location;
 851     }
 852   if (!ix && !current_function_decl)
 853     pedwarn ("%qD is not defined outside of function scope", decl);
 854
 855   return decl;
 856 }
 857
 858 /* Given a STRING_CST, give it a suitable array-of-chars data type.  */
 859
 860 tree
 861 fix_string_type (tree value)
 862 {
 863   const int wchar_bytes = TYPE_PRECISION (wchar_type_node) / BITS_PER_UNIT;
 864   const int wide_flag = TREE_TYPE (value) == wchar_array_type_node;
 865   int length = TREE_STRING_LENGTH (value);
 866   int nchars;
 867   tree e_type, i_type, a_type;
 868
 869   /* Compute the number of elements, for the array type.  */
 870   nchars = wide_flag ? length / wchar_bytes : length;
 871
 872   /* C89 2.2.4.1, C99 5.2.4.1 (Translation limits).  The analogous
 873      limit in C++98 Annex B is very large (65536) and is not normative,
 874      so we do not diagnose it (warn_overlength_strings is forced off
 875      in c_common_post_options).  */
 876   if (warn_overlength_strings)
 877     {
 878       const int nchars_max = flag_isoc99 ? 4095 : 509;
 879       const int relevant_std = flag_isoc99 ? 99 : 90;
 880       if (nchars - 1 > nchars_max)
 881         /* Translators: The %d after 'ISO C' will be 90 or 99.  Do not
 882            separate the %d from the 'C'.  'ISO' should not be
 883            translated, but it may be moved after 'C%d' in languages
 884            where modifiers follow nouns.  */
 885         pedwarn ("string length %qd is greater than the length %qd "
 886                  "ISO C%d compilers are required to support",
 887                  nchars - 1, nchars_max, relevant_std);
 888     }
 889
 890   /* Create the array type for the string constant.  The ISO C++
 891      standard says that a string literal has type `const char[N]' or
 892      `const wchar_t[N]'.  We use the same logic when invoked as a C
 893      front-end with -Wwrite-strings.
 894      ??? We should change the type of an expression depending on the
 895      state of a warning flag.  We should just be warning -- see how
 896      this is handled in the C++ front-end for the deprecated implicit
 897      conversion from string literals to `char*' or `wchar_t*'.
 898
 899      The C++ front end relies on TYPE_MAIN_VARIANT of a cv-qualified
 900      array type being the unqualified version of that type.
 901      Therefore, if we are constructing an array of const char, we must
 902      construct the matching unqualified array type first.  The C front
 903      end does not require this, but it does no harm, so we do it
 904      unconditionally.  */
 905   e_type = wide_flag ? wchar_type_node : char_type_node;
 906   i_type = build_index_type (build_int_cst (NULL_TREE, nchars - 1));
 907   a_type = build_array_type (e_type, i_type);
 908   if (c_dialect_cxx() || warn_write_strings)
 909     a_type = c_build_qualified_type (a_type, TYPE_QUAL_CONST);
 910
 911   TREE_TYPE (value) = a_type;
 912   TREE_CONSTANT (value) = 1;
 913   TREE_INVARIANT (value) = 1;
 914   TREE_READONLY (value) = 1;
 915   TREE_STATIC (value) = 1;
 916   return value;
 917 }
 918 \f
 919 /* Print a warning if a constant expression had overflow in folding.
 920    Invoke this function on every expression that the language
 921    requires to be a constant expression.
 922    Note the ANSI C standard says it is erroneous for a
 923    constant expression to overflow.  */
 924
 925 void
 926 constant_expression_warning (tree value)
 927 {
 928   if ((TREE_CODE (value) == INTEGER_CST || TREE_CODE (value) == REAL_CST
 929        || TREE_CODE (value) == VECTOR_CST
 930        || TREE_CODE (value) == COMPLEX_CST)
 931       && TREE_OVERFLOW (value)
 932       && warn_overflow
 933       && pedantic)
 934     pedwarn ("overflow in constant expression");
 935 }
 936
 937 /* Print a warning if an expression had overflow in folding and its
 938    operands hadn't.
 939
 940    Invoke this function on every expression that
 941    (1) appears in the source code, and
 942    (2) is a constant expression that overflowed, and
 943    (3) is not already checked by convert_and_check;
 944    however, do not invoke this function on operands of explicit casts
 945    or when the expression is the result of an operator and any operand
 946    already overflowed.  */
 947
 948 void
 949 overflow_warning (tree value)
 950 {
 951   if (skip_evaluation) return;
 952
 953   switch (TREE_CODE (value))
 954     {
 955     case INTEGER_CST:
 956       warning (OPT_Woverflow, "integer overflow in expression");
 957       break;
 958
 959     case REAL_CST:
 960       warning (OPT_Woverflow, "floating point overflow in expression");
 961       break;
 962
 963     case VECTOR_CST:
 964       warning (OPT_Woverflow, "vector overflow in expression");
 965       break;
 966
 967     case COMPLEX_CST:
 968       if (TREE_CODE (TREE_REALPART (value)) == INTEGER_CST)
 969         warning (OPT_Woverflow, "complex integer overflow in expression");
 970       else if (TREE_CODE (TREE_REALPART (value)) == REAL_CST)
 971         warning (OPT_Woverflow, "complex floating point overflow in expression");
 972       break;
 973
 974     default:
 975       break;
 976     }
 977 }
 978
 979
 980 /* Warn about use of a logical || / && operator being used in a
 981    context where it is likely that the bitwise equivalent was intended
 982    by the programmer. CODE is the TREE_CODE of the operator, ARG1
 983    and ARG2 the arguments.  */
 984
 985 void
 986 warn_logical_operator (enum tree_code code, tree arg1, tree
 987     arg2)
 988 {
 989   switch (code)
 990     {
 991       case TRUTH_ANDIF_EXPR:
 992       case TRUTH_ORIF_EXPR:
 993       case TRUTH_OR_EXPR:
 994       case TRUTH_AND_EXPR:
 995         if (!TREE_NO_WARNING (arg1)
 996             && INTEGRAL_TYPE_P (TREE_TYPE (arg1))
 997             && !CONSTANT_CLASS_P (arg1)
 998             && TREE_CODE (arg2) == INTEGER_CST
 999             && !integer_zerop (arg2))
1000           {
1001             warning (OPT_Wlogical_op,
1002                      "logical %<%s%> with non-zero constant "
1003                      "will always evaluate as true",
1004                      ((code == TRUTH_ANDIF_EXPR)
1005                       || (code == TRUTH_AND_EXPR)) ? "&&" : "||");
1006             TREE_NO_WARNING (arg1) = true;
1007           }
1008         break;
1009       default:
1010         break;
1011     }
1012 }
1013
1014
1015 /* Print a warning about casts that might indicate violation
1016    of strict aliasing rules if -Wstrict-aliasing is used and
1017    strict aliasing mode is in effect. OTYPE is the original
1018    TREE_TYPE of EXPR, and TYPE the type we're casting to. */
1019
1020 bool
1021 strict_aliasing_warning (tree otype, tree type, tree expr)
1022 {
1023   if (!(flag_strict_aliasing && POINTER_TYPE_P (type)
1024         && POINTER_TYPE_P (otype) && !VOID_TYPE_P (TREE_TYPE (type))))
1025     return false;
1026
1027   if ((warn_strict_aliasing > 1) && TREE_CODE (expr) == ADDR_EXPR
1028       && (DECL_P (TREE_OPERAND (expr, 0))
1029           || handled_component_p (TREE_OPERAND (expr, 0))))
1030     {
1031       /* Casting the address of an object to non void pointer. Warn
1032          if the cast breaks type based aliasing.  */
1033       if (!COMPLETE_TYPE_P (TREE_TYPE (type)) && warn_strict_aliasing == 2)
1034         {
1035           warning (OPT_Wstrict_aliasing, "type-punning to incomplete type "
1036                    "might break strict-aliasing rules");
1037           return true;
1038         }
1039       else
1040         {
1041           /* warn_strict_aliasing >= 3.   This includes the default (3).
1042              Only warn if the cast is dereferenced immediately.  */
1043           HOST_WIDE_INT set1 =
1044             get_alias_set (TREE_TYPE (TREE_OPERAND (expr, 0)));
1045           HOST_WIDE_INT set2 = get_alias_set (TREE_TYPE (type));
1046
1047           if (!alias_sets_conflict_p (set1, set2))
1048             {
1049               warning (OPT_Wstrict_aliasing, "dereferencing type-punned "
1050                        "pointer will break strict-aliasing rules");
1051               return true;
1052             }
1053           else if (warn_strict_aliasing == 2
1054                    && !alias_sets_might_conflict_p (set1, set2))
1055             {
1056               warning (OPT_Wstrict_aliasing, "dereferencing type-punned "
1057                        "pointer might break strict-aliasing rules");
1058               return true;
1059             }
1060         }
1061     }
1062   else
1063     if ((warn_strict_aliasing == 1) && !VOID_TYPE_P (TREE_TYPE (otype)))
1064       {
1065         /* At this level, warn for any conversions, even if an address is
1066            not taken in the same statement.  This will likely produce many
1067            false positives, but could be useful to pinpoint problems that
1068            are not revealed at higher levels.  */
1069         HOST_WIDE_INT set1 = get_alias_set (TREE_TYPE (otype));
1070         HOST_WIDE_INT set2 = get_alias_set (TREE_TYPE (type));
1071         if (!COMPLETE_TYPE_P(type)
1072             || !alias_sets_might_conflict_p (set1, set2))
1073           {
1074             warning (OPT_Wstrict_aliasing, "dereferencing type-punned "
1075                      "pointer might break strict-aliasing rules");
1076             return true;
1077           }
1078       }
1079
1080   return false;
1081 }
1082
1083 /* Print a warning about if (); or if () .. else; constructs
1084    via the special empty statement node that we create.  INNER_THEN
1085    and INNER_ELSE are the statement lists of the if and the else
1086    block.  */
1087
1088 void
1089 empty_if_body_warning (tree inner_then, tree inner_else)
1090 {
1091   if (TREE_CODE (inner_then) == STATEMENT_LIST
1092       && STATEMENT_LIST_TAIL (inner_then))
1093     inner_then = STATEMENT_LIST_TAIL (inner_then)->stmt;
1094
1095   if (inner_else && TREE_CODE (inner_else) == STATEMENT_LIST
1096       && STATEMENT_LIST_TAIL (inner_else))
1097     inner_else = STATEMENT_LIST_TAIL (inner_else)->stmt;
1098
1099   if (IS_EMPTY_STMT (inner_then) && !inner_else)
1100     warning (OPT_Wempty_body, "%Hsuggest braces around empty body "
1101              "in an %<if%> statement", EXPR_LOCUS (inner_then));
1102
1103   else if (inner_else && IS_EMPTY_STMT (inner_else))
1104     warning (OPT_Wempty_body, "%Hsuggest braces around empty body "
1105              "in an %<else%> statement", EXPR_LOCUS (inner_else));
1106 }
1107
1108 /* Warn for unlikely, improbable, or stupid DECL declarations
1109    of `main'.  */
1110
1111 void
1112 check_main_parameter_types (tree decl)
1113 {
1114   tree args;
1115   int argct = 0;
1116
1117   for (args = TYPE_ARG_TYPES (TREE_TYPE (decl)); args;
1118       args = TREE_CHAIN (args))
1119    {
1120      tree type = args ? TREE_VALUE (args) : 0;
1121
1122      if (type == void_type_node || type == error_mark_node )
1123        break;
1124
1125      ++argct;
1126      switch (argct)
1127        {
1128        case 1:
1129          if (TYPE_MAIN_VARIANT (type) != integer_type_node)
1130            pedwarn ("first argument of %q+D should be %<int%>", decl);
1131          break;
1132
1133        case 2:
1134          if (TREE_CODE (type) != POINTER_TYPE
1135              || TREE_CODE (TREE_TYPE (type)) != POINTER_TYPE
1136              || (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (type)))
1137                  != char_type_node))
1138            pedwarn ("second argument of %q+D should be %<char **%>",
1139                     decl);
1140          break;
1141
1142        case 3:
1143          if (TREE_CODE (type) != POINTER_TYPE
1144              || TREE_CODE (TREE_TYPE (type)) != POINTER_TYPE
1145              || (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (type)))
1146                  != char_type_node))
1147            pedwarn ("third argument of %q+D should probably be "
1148                     "%<char **%>", decl);
1149          break;
1150        }
1151    }
1152
1153   /* It is intentional that this message does not mention the third
1154     argument because it's only mentioned in an appendix of the
1155     standard.  */
1156   if (argct > 0 && (argct < 2 || argct > 3))
1157    pedwarn ("%q+D takes only zero or two arguments", decl);
1158 }
1159
1160 /* True if vector types T1 and T2 can be converted to each other
1161    without an explicit cast.  If EMIT_LAX_NOTE is true, and T1 and T2
1162    can only be converted with -flax-vector-conversions yet that is not
1163    in effect, emit a note telling the user about that option if such
1164    a note has not previously been emitted.  */
1165 bool
1166 vector_types_convertible_p (tree t1, tree t2, bool emit_lax_note)
1167 {
1168   static bool emitted_lax_note = false;
1169   bool convertible_lax;
1170
1171   if ((targetm.vector_opaque_p (t1) || targetm.vector_opaque_p (t2))
1172       && tree_int_cst_equal (TYPE_SIZE (t1), TYPE_SIZE (t2)))
1173     return true;
1174
1175   convertible_lax =
1176     (tree_int_cst_equal (TYPE_SIZE (t1), TYPE_SIZE (t2))
1177      && (TREE_CODE (TREE_TYPE (t1)) != REAL_TYPE ||
1178          TYPE_PRECISION (t1) == TYPE_PRECISION (t2))
1179      && (INTEGRAL_TYPE_P (TREE_TYPE (t1))
1180          == INTEGRAL_TYPE_P (TREE_TYPE (t2))));
1181
1182   if (!convertible_lax || flag_lax_vector_conversions)
1183     return convertible_lax;
1184
1185   if (TYPE_VECTOR_SUBPARTS (t1) == TYPE_VECTOR_SUBPARTS (t2)
1186       && comptypes (TREE_TYPE (t1), TREE_TYPE (t2)))
1187     return true;
1188
1189   if (emit_lax_note && !emitted_lax_note)
1190     {
1191       emitted_lax_note = true;
1192       inform ("use -flax-vector-conversions to permit "
1193               "conversions between vectors with differing "
1194               "element types or numbers of subparts");
1195     }
1196
1197   return false;
1198 }
1199
1200 /* Warns if the conversion of EXPR to TYPE may alter a value.
1201    This is a helper function for warnings_for_convert_and_check.  */
1202
1203 static void
1204 conversion_warning (tree type, tree expr)
1205 {
1206   bool give_warning = false;
1207
1208   unsigned int formal_prec = TYPE_PRECISION (type);
1209
1210   if (!warn_conversion && !warn_sign_conversion)
1211     return;
1212
1213   if (TREE_CODE (expr) == REAL_CST || TREE_CODE (expr) == INTEGER_CST)
1214     {
1215       /* Warn for real constant that is not an exact integer converted
1216          to integer type.  */
1217       if (TREE_CODE (TREE_TYPE (expr)) == REAL_TYPE
1218           && TREE_CODE (type) == INTEGER_TYPE)
1219         {
1220           if (!real_isinteger (TREE_REAL_CST_PTR (expr), TYPE_MODE (TREE_TYPE (expr))))
1221             give_warning = true;
1222         }
1223       /* Warn for an integer constant that does not fit into integer type.  */
1224       else if (TREE_CODE (TREE_TYPE (expr)) == INTEGER_TYPE
1225                && TREE_CODE (type) == INTEGER_TYPE
1226                && !int_fits_type_p (expr, type))
1227         {
1228           if (TYPE_UNSIGNED (type) && !TYPE_UNSIGNED (TREE_TYPE (expr)))
1229             warning (OPT_Wsign_conversion,
1230                      "negative integer implicitly converted to unsigned type");
1231           else if (!TYPE_UNSIGNED (type) && TYPE_UNSIGNED (TREE_TYPE (expr)))
1232             warning (OPT_Wsign_conversion,
1233                      "conversion of unsigned constant value to negative integer");
1234           else
1235             give_warning = true;
1236         }
1237       else if (TREE_CODE (type) == REAL_TYPE)
1238         {
1239           /* Warn for an integer constant that does not fit into real type.  */
1240           if (TREE_CODE (TREE_TYPE (expr)) == INTEGER_TYPE)
1241             {
1242               REAL_VALUE_TYPE a = real_value_from_int_cst (0, expr);
1243               if (!exact_real_truncate (TYPE_MODE (type), &a))
1244                 give_warning = true;
1245             }
1246           /* Warn for a real constant that does not fit into a smaller
1247              real type.  */
1248           else if (TREE_CODE (TREE_TYPE (expr)) == REAL_TYPE
1249                    && formal_prec < TYPE_PRECISION (TREE_TYPE (expr)))
1250             {
1251               REAL_VALUE_TYPE a = TREE_REAL_CST (expr);
1252               if (!exact_real_truncate (TYPE_MODE (type), &a))
1253                 give_warning = true;
1254             }
1255         }
1256
1257       if (give_warning)
1258         warning (OPT_Wconversion,
1259                  "conversion to %qT alters %qT constant value",
1260                  type, TREE_TYPE (expr));
1261     }
1262   else /* 'expr' is not a constant.  */
1263     {
1264       /* Warn for real types converted to integer types.  */
1265       if (TREE_CODE (TREE_TYPE (expr)) == REAL_TYPE
1266           && TREE_CODE (type) == INTEGER_TYPE)
1267         give_warning = true;
1268
1269       else if (TREE_CODE (TREE_TYPE (expr)) == INTEGER_TYPE
1270                && TREE_CODE (type) == INTEGER_TYPE)
1271         {
1272           /* Warn for integer types converted to smaller integer types.  */
1273           if (formal_prec < TYPE_PRECISION (TREE_TYPE (expr)))
1274             give_warning = true;
1275
1276           /* When they are the same width but different signedness,
1277              then the value may change.  */
1278           else if ((formal_prec == TYPE_PRECISION (TREE_TYPE (expr))
1279                     && TYPE_UNSIGNED (TREE_TYPE (expr)) != TYPE_UNSIGNED (type))
1280                    /* Even when converted to a bigger type, if the type is
1281                       unsigned but expr is signed, then negative values
1282                       will be changed.  */
1283                    || (TYPE_UNSIGNED (type) && !TYPE_UNSIGNED (TREE_TYPE (expr))))
1284             warning (OPT_Wsign_conversion,
1285                      "conversion to %qT from %qT may change the sign of the result",
1286                      type, TREE_TYPE (expr));
1287         }
1288
1289       /* Warn for integer types converted to real types if and only if
1290          all the range of values of the integer type cannot be
1291          represented by the real type.  */
1292       else if (TREE_CODE (TREE_TYPE (expr)) == INTEGER_TYPE
1293                && TREE_CODE (type) == REAL_TYPE)
1294         {
1295           tree type_low_bound = TYPE_MIN_VALUE (TREE_TYPE (expr));
1296           tree type_high_bound = TYPE_MAX_VALUE (TREE_TYPE (expr));
1297           REAL_VALUE_TYPE real_low_bound = real_value_from_int_cst (0, type_low_bound);
1298           REAL_VALUE_TYPE real_high_bound = real_value_from_int_cst (0, type_high_bound);
1299
1300           if (!exact_real_truncate (TYPE_MODE (type), &real_low_bound)
1301               || !exact_real_truncate (TYPE_MODE (type), &real_high_bound))
1302             give_warning = true;
1303         }
1304
1305       /* Warn for real types converted to smaller real types.  */
1306       else if (TREE_CODE (TREE_TYPE (expr)) == REAL_TYPE
1307                && TREE_CODE (type) == REAL_TYPE
1308                && formal_prec < TYPE_PRECISION (TREE_TYPE (expr)))
1309         give_warning = true;
1310
1311
1312       if (give_warning)
1313         warning (OPT_Wconversion,
1314                  "conversion to %qT from %qT may alter its value",
1315                  type, TREE_TYPE (expr));
1316     }
1317 }
1318
1319 /* Produce warnings after a conversion. RESULT is the result of
1320    converting EXPR to TYPE.  This is a helper function for
1321    convert_and_check and cp_convert_and_check.  */
1322
1323 void
1324 warnings_for_convert_and_check (tree type, tree expr, tree result)
1325 {
1326   if (TREE_CODE (expr) == INTEGER_CST
1327       && (TREE_CODE (type) == INTEGER_TYPE
1328           || TREE_CODE (type) == ENUMERAL_TYPE)
1329       && !int_fits_type_p (expr, type))
1330     {
1331       /* Do not diagnose overflow in a constant expression merely
1332          because a conversion overflowed.  */
1333       if (TREE_OVERFLOW (result))
1334         TREE_OVERFLOW (result) = TREE_OVERFLOW (expr);
1335
1336       if (TYPE_UNSIGNED (type))
1337         {
1338           /* This detects cases like converting -129 or 256 to
1339              unsigned char.  */
1340           if (!int_fits_type_p (expr, c_common_signed_type (type)))
1341             warning (OPT_Woverflow,
1342                      "large integer implicitly truncated to unsigned type");
1343           else
1344             conversion_warning (type, expr);
1345         }
1346       else if (!int_fits_type_p (expr, unsigned_type_for (type)))
1347         warning (OPT_Woverflow,
1348                  "overflow in implicit constant conversion");
1349       /* No warning for converting 0x80000000 to int.  */
1350       else if (pedantic
1351                && (TREE_CODE (TREE_TYPE (expr)) != INTEGER_TYPE
1352                    || TYPE_PRECISION (TREE_TYPE (expr))
1353                    != TYPE_PRECISION (type)))
1354         warning (OPT_Woverflow,
1355                  "overflow in implicit constant conversion");
1356
1357       else
1358         conversion_warning (type, expr);
1359     }
1360   else if (TREE_CODE (result) == INTEGER_CST && TREE_OVERFLOW (result))
1361     warning (OPT_Woverflow,
1362              "overflow in implicit constant conversion");
1363   else
1364     conversion_warning (type, expr);
1365 }
1366
1367
1368 /* Convert EXPR to TYPE, warning about conversion problems with constants.
1369    Invoke this function on every expression that is converted implicitly,
1370    i.e. because of language rules and not because of an explicit cast.  */
1371
1372 tree
1373 convert_and_check (tree type, tree expr)
1374 {
1375   tree result;
1376
1377   if (TREE_TYPE (expr) == type)
1378     return expr;
1379
1380   result = convert (type, expr);
1381
1382   if (!skip_evaluation && !TREE_OVERFLOW_P (expr) && result != error_mark_node)
1383     warnings_for_convert_and_check (type, expr, result);
1384
1385   return result;
1386 }
1387 \f
1388 /* A node in a list that describes references to variables (EXPR), which are
1389    either read accesses if WRITER is zero, or write accesses, in which case
1390    WRITER is the parent of EXPR.  */
1391 struct tlist
1392 {
1393   struct tlist *next;
1394   tree expr, writer;
1395 };
1396
1397 /* Used to implement a cache the results of a call to verify_tree.  We only
1398    use this for SAVE_EXPRs.  */
1399 struct tlist_cache
1400 {
1401   struct tlist_cache *next;
1402   struct tlist *cache_before_sp;
1403   struct tlist *cache_after_sp;
1404   tree expr;
1405 };
1406
1407 /* Obstack to use when allocating tlist structures, and corresponding
1408    firstobj.  */
1409 static struct obstack tlist_obstack;
1410 static char *tlist_firstobj = 0;
1411
1412 /* Keep track of the identifiers we've warned about, so we can avoid duplicate
1413    warnings.  */
1414 static struct tlist *warned_ids;
1415 /* SAVE_EXPRs need special treatment.  We process them only once and then
1416    cache the results.  */
1417 static struct tlist_cache *save_expr_cache;
1418
1419 static void add_tlist (struct tlist **, struct tlist *, tree, int);
1420 static void merge_tlist (struct tlist **, struct tlist *, int);
1421 static void verify_tree (tree, struct tlist **, struct tlist **, tree);
1422 static int warning_candidate_p (tree);
1423 static void warn_for_collisions (struct tlist *);
1424 static void warn_for_collisions_1 (tree, tree, struct tlist *, int);
1425 static struct tlist *new_tlist (struct tlist *, tree, tree);
1426
1427 /* Create a new struct tlist and fill in its fields.  */
1428 static struct tlist *
1429 new_tlist (struct tlist *next, tree t, tree writer)
1430 {
1431   struct tlist *l;
1432   l = XOBNEW (&tlist_obstack, struct tlist);
1433   l->next = next;
1434   l->expr = t;
1435   l->writer = writer;
1436   return l;
1437 }
1438
1439 /* Add duplicates of the nodes found in ADD to the list *TO.  If EXCLUDE_WRITER
1440    is nonnull, we ignore any node we find which has a writer equal to it.  */
1441
1442 static void
1443 add_tlist (struct tlist **to, struct tlist *add, tree exclude_writer, int copy)
1444 {
1445   while (add)
1446     {
1447       struct tlist *next = add->next;
1448       if (!copy)
1449         add->next = *to;
1450       if (!exclude_writer || add->writer != exclude_writer)
1451         *to = copy ? new_tlist (*to, add->expr, add->writer) : add;
1452       add = next;
1453     }
1454 }
1455
1456 /* Merge the nodes of ADD into TO.  This merging process is done so that for
1457    each variable that already exists in TO, no new node is added; however if
1458    there is a write access recorded in ADD, and an occurrence on TO is only
1459    a read access, then the occurrence in TO will be modified to record the
1460    write.  */
1461
1462 static void
1463 merge_tlist (struct tlist **to, struct tlist *add, int copy)
1464 {
1465   struct tlist **end = to;
1466
1467   while (*end)
1468     end = &(*end)->next;
1469
1470   while (add)
1471     {
1472       int found = 0;
1473       struct tlist *tmp2;
1474       struct tlist *next = add->next;
1475
1476       for (tmp2 = *to; tmp2; tmp2 = tmp2->next)
1477         if (tmp2->expr == add->expr)
1478           {
1479             found = 1;
1480             if (!tmp2->writer)
1481               tmp2->writer = add->writer;
1482           }
1483       if (!found)
1484         {
1485           *end = copy ? add : new_tlist (NULL, add->expr, add->writer);
1486           end = &(*end)->next;
1487           *end = 0;
1488         }
1489       add = next;
1490     }
1491 }
1492
1493 /* WRITTEN is a variable, WRITER is its parent.  Warn if any of the variable
1494    references in list LIST conflict with it, excluding reads if ONLY writers
1495    is nonzero.  */
1496
1497 static void
1498 warn_for_collisions_1 (tree written, tree writer, struct tlist *list,
1499                        int only_writes)
1500 {
1501   struct tlist *tmp;
1502
1503   /* Avoid duplicate warnings.  */
1504   for (tmp = warned_ids; tmp; tmp = tmp->next)
1505     if (tmp->expr == written)
1506       return;
1507
1508   while (list)
1509     {
1510       if (list->expr == written
1511           && list->writer != writer
1512           && (!only_writes || list->writer)
1513           && DECL_NAME (list->expr))
1514         {
1515           warned_ids = new_tlist (warned_ids, written, NULL_TREE);
1516           warning (0, "operation on %qE may be undefined", list->expr);
1517         }
1518       list = list->next;
1519     }
1520 }
1521
1522 /* Given a list LIST of references to variables, find whether any of these
1523    can cause conflicts due to missing sequence points.  */
1524
1525 static void
1526 warn_for_collisions (struct tlist *list)
1527 {
1528   struct tlist *tmp;
1529
1530   for (tmp = list; tmp; tmp = tmp->next)
1531     {
1532       if (tmp->writer)
1533         warn_for_collisions_1 (tmp->expr, tmp->writer, list, 0);
1534     }
1535 }
1536
1537 /* Return nonzero if X is a tree that can be verified by the sequence point
1538    warnings.  */
1539 static int
1540 warning_candidate_p (tree x)
1541 {
1542   return TREE_CODE (x) == VAR_DECL || TREE_CODE (x) == PARM_DECL;
1543 }
1544
1545 /* Walk the tree X, and record accesses to variables.  If X is written by the
1546    parent tree, WRITER is the parent.
1547    We store accesses in one of the two lists: PBEFORE_SP, and PNO_SP.  If this
1548    expression or its only operand forces a sequence point, then everything up
1549    to the sequence point is stored in PBEFORE_SP.  Everything else gets stored
1550    in PNO_SP.
1551    Once we return, we will have emitted warnings if any subexpression before
1552    such a sequence point could be undefined.  On a higher level, however, the
1553    sequence point may not be relevant, and we'll merge the two lists.
1554
1555    Example: (b++, a) + b;
1556    The call that processes the COMPOUND_EXPR will store the increment of B
1557    in PBEFORE_SP, and the use of A in PNO_SP.  The higher-level call that
1558    processes the PLUS_EXPR will need to merge the two lists so that
1559    eventually, all accesses end up on the same list (and we'll warn about the
1560    unordered subexpressions b++ and b.
1561
1562    A note on merging.  If we modify the former example so that our expression
1563    becomes
1564      (b++, b) + a
1565    care must be taken not simply to add all three expressions into the final
1566    PNO_SP list.  The function merge_tlist takes care of that by merging the
1567    before-SP list of the COMPOUND_EXPR into its after-SP list in a special
1568    way, so that no more than one access to B is recorded.  */
1569
1570 static void
1571 verify_tree (tree x, struct tlist **pbefore_sp, struct tlist **pno_sp,
1572              tree writer)
1573 {
1574   struct tlist *tmp_before, *tmp_nosp, *tmp_list2, *tmp_list3;
1575   enum tree_code code;
1576   enum tree_code_class cl;
1577
1578   /* X may be NULL if it is the operand of an empty statement expression
1579      ({ }).  */
1580   if (x == NULL)
1581     return;
1582
1583  restart:
1584   code = TREE_CODE (x);
1585   cl = TREE_CODE_CLASS (code);
1586
1587   if (warning_candidate_p (x))
1588     {
1589       *pno_sp = new_tlist (*pno_sp, x, writer);
1590       return;
1591     }
1592
1593   switch (code)
1594     {
1595     case CONSTRUCTOR:
1596       return;
1597
1598     case COMPOUND_EXPR:
1599     case TRUTH_ANDIF_EXPR:
1600     case TRUTH_ORIF_EXPR:
1601       tmp_before = tmp_nosp = tmp_list3 = 0;
1602       verify_tree (TREE_OPERAND (x, 0), &tmp_before, &tmp_nosp, NULL_TREE);
1603       warn_for_collisions (tmp_nosp);
1604       merge_tlist (pbefore_sp, tmp_before, 0);
1605       merge_tlist (pbefore_sp, tmp_nosp, 0);
1606       verify_tree (TREE_OPERAND (x, 1), &tmp_list3, pno_sp, NULL_TREE);
1607       merge_tlist (pbefore_sp, tmp_list3, 0);
1608       return;
1609
1610     case COND_EXPR:
1611       tmp_before = tmp_list2 = 0;
1612       verify_tree (TREE_OPERAND (x, 0), &tmp_before, &tmp_list2, NULL_TREE);
1613       warn_for_collisions (tmp_list2);
1614       merge_tlist (pbefore_sp, tmp_before, 0);
1615       merge_tlist (pbefore_sp, tmp_list2, 1);
1616
1617       tmp_list3 = tmp_nosp = 0;
1618       verify_tree (TREE_OPERAND (x, 1), &tmp_list3, &tmp_nosp, NULL_TREE);
1619       warn_for_collisions (tmp_nosp);
1620       merge_tlist (pbefore_sp, tmp_list3, 0);
1621
1622       tmp_list3 = tmp_list2 = 0;
1623       verify_tree (TREE_OPERAND (x, 2), &tmp_list3, &tmp_list2, NULL_TREE);
1624       warn_for_collisions (tmp_list2);
1625       merge_tlist (pbefore_sp, tmp_list3, 0);
1626       /* Rather than add both tmp_nosp and tmp_list2, we have to merge the
1627          two first, to avoid warning for (a ? b++ : b++).  */
1628       merge_tlist (&tmp_nosp, tmp_list2, 0);
1629       add_tlist (pno_sp, tmp_nosp, NULL_TREE, 0);
1630       return;
1631
1632     case PREDECREMENT_EXPR:
1633     case PREINCREMENT_EXPR:
1634     case POSTDECREMENT_EXPR:
1635     case POSTINCREMENT_EXPR:
1636       verify_tree (TREE_OPERAND (x, 0), pno_sp, pno_sp, x);
1637       return;
1638
1639     case MODIFY_EXPR:
1640       tmp_before = tmp_nosp = tmp_list3 = 0;
1641       verify_tree (TREE_OPERAND (x, 1), &tmp_before, &tmp_nosp, NULL_TREE);
1642       verify_tree (TREE_OPERAND (x, 0), &tmp_list3, &tmp_list3, x);
1643       /* Expressions inside the LHS are not ordered wrt. the sequence points
1644          in the RHS.  Example:
1645            *a = (a++, 2)
1646          Despite the fact that the modification of "a" is in the before_sp
1647          list (tmp_before), it conflicts with the use of "a" in the LHS.
1648          We can handle this by adding the contents of tmp_list3
1649          to those of tmp_before, and redoing the collision warnings for that
1650          list.  */
1651       add_tlist (&tmp_before, tmp_list3, x, 1);
1652       warn_for_collisions (tmp_before);
1653       /* Exclude the LHS itself here; we first have to merge it into the
1654          tmp_nosp list.  This is done to avoid warning for "a = a"; if we
1655          didn't exclude the LHS, we'd get it twice, once as a read and once
1656          as a write.  */
1657       add_tlist (pno_sp, tmp_list3, x, 0);
1658       warn_for_collisions_1 (TREE_OPERAND (x, 0), x, tmp_nosp, 1);
1659
1660       merge_tlist (pbefore_sp, tmp_before, 0);
1661       if (warning_candidate_p (TREE_OPERAND (x, 0)))
1662         merge_tlist (&tmp_nosp, new_tlist (NULL, TREE_OPERAND (x, 0), x), 0);
1663       add_tlist (pno_sp, tmp_nosp, NULL_TREE, 1);
1664       return;
1665
1666     case CALL_EXPR:
1667       /* We need to warn about conflicts among arguments and conflicts between
1668          args and the function address.  Side effects of the function address,
1669          however, are not ordered by the sequence point of the call.  */
1670       {
1671         call_expr_arg_iterator iter;
1672         tree arg;
1673         tmp_before = tmp_nosp = 0;
1674         verify_tree (CALL_EXPR_FN (x), &tmp_before, &tmp_nosp, NULL_TREE);
1675         FOR_EACH_CALL_EXPR_ARG (arg, iter, x)
1676           {
1677             tmp_list2 = tmp_list3 = 0;
1678             verify_tree (arg, &tmp_list2, &tmp_list3, NULL_TREE);
1679             merge_tlist (&tmp_list3, tmp_list2, 0);
1680             add_tlist (&tmp_before, tmp_list3, NULL_TREE, 0);
1681           }
1682         add_tlist (&tmp_before, tmp_nosp, NULL_TREE, 0);
1683         warn_for_collisions (tmp_before);
1684         add_tlist (pbefore_sp, tmp_before, NULL_TREE, 0);
1685         return;
1686       }
1687
1688     case TREE_LIST:
1689       /* Scan all the list, e.g. indices of multi dimensional array.  */
1690       while (x)
1691         {
1692           tmp_before = tmp_nosp = 0;
1693           verify_tree (TREE_VALUE (x), &tmp_before, &tmp_nosp, NULL_TREE);
1694           merge_tlist (&tmp_nosp, tmp_before, 0);
1695           add_tlist (pno_sp, tmp_nosp, NULL_TREE, 0);
1696           x = TREE_CHAIN (x);
1697         }
1698       return;
1699
1700     case SAVE_EXPR:
1701       {
1702         struct tlist_cache *t;
1703         for (t = save_expr_cache; t; t = t->next)
1704           if (t->expr == x)
1705             break;
1706
1707         if (!t)
1708           {
1709             t = XOBNEW (&tlist_obstack, struct tlist_cache);
1710             t->next = save_expr_cache;
1711             t->expr = x;
1712             save_expr_cache = t;
1713
1714             tmp_before = tmp_nosp = 0;
1715             verify_tree (TREE_OPERAND (x, 0), &tmp_before, &tmp_nosp, NULL_TREE);
1716             warn_for_collisions (tmp_nosp);
1717
1718             tmp_list3 = 0;
1719             while (tmp_nosp)
1720               {
1721                 struct tlist *t = tmp_nosp;
1722                 tmp_nosp = t->next;
1723                 merge_tlist (&tmp_list3, t, 0);
1724               }
1725             t->cache_before_sp = tmp_before;
1726             t->cache_after_sp = tmp_list3;
1727           }
1728         merge_tlist (pbefore_sp, t->cache_before_sp, 1);
1729         add_tlist (pno_sp, t->cache_after_sp, NULL_TREE, 1);
1730         return;
1731       }
1732
1733     default:
1734       /* For other expressions, simply recurse on their operands.
1735          Manual tail recursion for unary expressions.
1736          Other non-expressions need not be processed.  */
1737       if (cl == tcc_unary)
1738         {
1739           x = TREE_OPERAND (x, 0);
1740           writer = 0;
1741           goto restart;
1742         }
1743       else if (IS_EXPR_CODE_CLASS (cl))
1744         {
1745           int lp;
1746           int max = TREE_OPERAND_LENGTH (x);
1747           for (lp = 0; lp < max; lp++)
1748             {
1749               tmp_before = tmp_nosp = 0;
1750               verify_tree (TREE_OPERAND (x, lp), &tmp_before, &tmp_nosp, 0);
1751               merge_tlist (&tmp_nosp, tmp_before, 0);
1752               add_tlist (pno_sp, tmp_nosp, NULL_TREE, 0);
1753             }
1754         }
1755       return;
1756     }
1757 }
1758
1759 /* Try to warn for undefined behavior in EXPR due to missing sequence
1760    points.  */
1761
1762 void
1763 verify_sequence_points (tree expr)
1764 {
1765   struct tlist *before_sp = 0, *after_sp = 0;
1766
1767   warned_ids = 0;
1768   save_expr_cache = 0;
1769   if (tlist_firstobj == 0)
1770     {
1771       gcc_obstack_init (&tlist_obstack);
1772       tlist_firstobj = (char *) obstack_alloc (&tlist_obstack, 0);
1773     }
1774
1775   verify_tree (expr, &before_sp, &after_sp, 0);
1776   warn_for_collisions (after_sp);
1777   obstack_free (&tlist_obstack, tlist_firstobj);
1778 }
1779 \f
1780 /* Validate the expression after `case' and apply default promotions.  */
1781
1782 static tree
1783 check_case_value (tree value)
1784 {
1785   if (value == NULL_TREE)
1786     return value;
1787
1788   /* ??? Can we ever get nops here for a valid case value?  We
1789      shouldn't for C.  */
1790   STRIP_TYPE_NOPS (value);
1791   /* In C++, the following is allowed:
1792
1793        const int i = 3;
1794        switch (...) { case i: ... }
1795
1796      So, we try to reduce the VALUE to a constant that way.  */
1797   if (c_dialect_cxx ())
1798     {
1799       value = decl_constant_value (value);
1800       STRIP_TYPE_NOPS (value);
1801       value = fold (value);
1802     }
1803
1804   if (TREE_CODE (value) == INTEGER_CST)
1805     /* Promote char or short to int.  */
1806     value = perform_integral_promotions (value);
1807   else if (value != error_mark_node)
1808     {
1809       error ("case label does not reduce to an integer constant");
1810       value = error_mark_node;
1811     }
1812
1813   constant_expression_warning (value);
1814
1815   return value;
1816 }
1817 \f
1818 /* See if the case values LOW and HIGH are in the range of the original
1819    type (i.e. before the default conversion to int) of the switch testing
1820    expression.
1821    TYPE is the promoted type of the testing expression, and ORIG_TYPE is
1822    the type before promoting it.  CASE_LOW_P is a pointer to the lower
1823    bound of the case label, and CASE_HIGH_P is the upper bound or NULL
1824    if the case is not a case range.
1825    The caller has to make sure that we are not called with NULL for
1826    CASE_LOW_P (i.e. the default case).
1827    Returns true if the case label is in range of ORIG_TYPE (saturated or
1828    untouched) or false if the label is out of range.  */
1829
1830 static bool
1831 check_case_bounds (tree type, tree orig_type,
1832                    tree *case_low_p, tree *case_high_p)
1833 {
1834   tree min_value, max_value;
1835   tree case_low = *case_low_p;
1836   tree case_high = case_high_p ? *case_high_p : case_low;
1837
1838   /* If there was a problem with the original type, do nothing.  */
1839   if (orig_type == error_mark_node)
1840     return true;
1841
1842   min_value = TYPE_MIN_VALUE (orig_type);
1843   max_value = TYPE_MAX_VALUE (orig_type);
1844
1845   /* Case label is less than minimum for type.  */
1846   if (tree_int_cst_compare (case_low, min_value) < 0
1847       && tree_int_cst_compare (case_high, min_value) < 0)
1848     {
1849       warning (0, "case label value is less than minimum value for type");
1850       return false;
1851     }
1852
1853   /* Case value is greater than maximum for type.  */
1854   if (tree_int_cst_compare (case_low, max_value) > 0
1855       && tree_int_cst_compare (case_high, max_value) > 0)
1856     {
1857       warning (0, "case label value exceeds maximum value for type");
1858       return false;
1859     }
1860
1861   /* Saturate lower case label value to minimum.  */
1862   if (tree_int_cst_compare (case_high, min_value) >= 0
1863       && tree_int_cst_compare (case_low, min_value) < 0)
1864     {
1865       warning (0, "lower value in case label range"
1866                " less than minimum value for type");
1867       case_low = min_value;
1868     }
1869
1870   /* Saturate upper case label value to maximum.  */
1871   if (tree_int_cst_compare (case_low, max_value) <= 0
1872       && tree_int_cst_compare (case_high, max_value) > 0)
1873     {
1874       warning (0, "upper value in case label range"
1875                " exceeds maximum value for type");
1876       case_high = max_value;
1877     }
1878
1879   if (*case_low_p != case_low)
1880     *case_low_p = convert (type, case_low);
1881   if (case_high_p && *case_high_p != case_high)
1882     *case_high_p = convert (type, case_high);
1883
1884   return true;
1885 }
1886 \f
1887 /* Return an integer type with BITS bits of precision,
1888    that is unsigned if UNSIGNEDP is nonzero, otherwise signed.  */
1889
1890 tree
1891 c_common_type_for_size (unsigned int bits, int unsignedp)
1892 {
1893   if (bits == TYPE_PRECISION (integer_type_node))
1894     return unsignedp ? unsigned_type_node : integer_type_node;
1895
1896   if (bits == TYPE_PRECISION (signed_char_type_node))
1897     return unsignedp ? unsigned_char_type_node : signed_char_type_node;
1898
1899   if (bits == TYPE_PRECISION (short_integer_type_node))
1900     return unsignedp ? short_unsigned_type_node : short_integer_type_node;
1901
1902   if (bits == TYPE_PRECISION (long_integer_type_node))
1903     return unsignedp ? long_unsigned_type_node : long_integer_type_node;
1904
1905   if (bits == TYPE_PRECISION (long_long_integer_type_node))
1906     return (unsignedp ? long_long_unsigned_type_node
1907             : long_long_integer_type_node);
1908
1909   if (bits == TYPE_PRECISION (widest_integer_literal_type_node))
1910     return (unsignedp ? widest_unsigned_literal_type_node
1911             : widest_integer_literal_type_node);
1912
1913   if (bits <= TYPE_PRECISION (intQI_type_node))
1914     return unsignedp ? unsigned_intQI_type_node : intQI_type_node;
1915
1916   if (bits <= TYPE_PRECISION (intHI_type_node))
1917     return unsignedp ? unsigned_intHI_type_node : intHI_type_node;
1918
1919   if (bits <= TYPE_PRECISION (intSI_type_node))
1920     return unsignedp ? unsigned_intSI_type_node : intSI_type_node;
1921
1922   if (bits <= TYPE_PRECISION (intDI_type_node))
1923     return unsignedp ? unsigned_intDI_type_node : intDI_type_node;
1924
1925   return 0;
1926 }
1927
1928 /* Used for communication between c_common_type_for_mode and
1929    c_register_builtin_type.  */
1930 static GTY(()) tree registered_builtin_types;
1931
1932 /* Return a data type that has machine mode MODE.
1933    If the mode is an integer,
1934    then UNSIGNEDP selects between signed and unsigned types.  */
1935
1936 tree
1937 c_common_type_for_mode (enum machine_mode mode, int unsignedp)
1938 {
1939   tree t;
1940
1941   if (mode == TYPE_MODE (integer_type_node))
1942     return unsignedp ? unsigned_type_node : integer_type_node;
1943
1944   if (mode == TYPE_MODE (signed_char_type_node))
1945     return unsignedp ? unsigned_char_type_node : signed_char_type_node;
1946
1947   if (mode == TYPE_MODE (short_integer_type_node))
1948     return unsignedp ? short_unsigned_type_node : short_integer_type_node;
1949
1950   if (mode == TYPE_MODE (long_integer_type_node))
1951     return unsignedp ? long_unsigned_type_node : long_integer_type_node;
1952
1953   if (mode == TYPE_MODE (long_long_integer_type_node))
1954     return unsignedp ? long_long_unsigned_type_node : long_long_integer_type_node;
1955
1956   if (mode == TYPE_MODE (widest_integer_literal_type_node))
1957     return unsignedp ? widest_unsigned_literal_type_node
1958                      : widest_integer_literal_type_node;
1959
1960   if (mode == QImode)
1961     return unsignedp ? unsigned_intQI_type_node : intQI_type_node;
1962
1963   if (mode == HImode)
1964     return unsignedp ? unsigned_intHI_type_node : intHI_type_node;
1965
1966   if (mode == SImode)
1967     return unsignedp ? unsigned_intSI_type_node : intSI_type_node;
1968
1969   if (mode == DImode)
1970     return unsignedp ? unsigned_intDI_type_node : intDI_type_node;
1971
1972 #if HOST_BITS_PER_WIDE_INT >= 64
1973   if (mode == TYPE_MODE (intTI_type_node))
1974     return unsignedp ? unsigned_intTI_type_node : intTI_type_node;
1975 #endif
1976
1977   if (mode == TYPE_MODE (float_type_node))
1978     return float_type_node;
1979
1980   if (mode == TYPE_MODE (double_type_node))
1981     return double_type_node;
1982
1983   if (mode == TYPE_MODE (long_double_type_node))
1984     return long_double_type_node;
1985
1986   if (mode == TYPE_MODE (void_type_node))
1987     return void_type_node;
1988
1989   if (mode == TYPE_MODE (build_pointer_type (char_type_node)))
1990     return (unsignedp
1991             ? make_unsigned_type (GET_MODE_PRECISION (mode))
1992             : make_signed_type (GET_MODE_PRECISION (mode)));
1993
1994   if (mode == TYPE_MODE (build_pointer_type (integer_type_node)))
1995     return (unsignedp
1996             ? make_unsigned_type (GET_MODE_PRECISION (mode))
1997             : make_signed_type (GET_MODE_PRECISION (mode)));
1998
1999   if (COMPLEX_MODE_P (mode))
2000     {
2001       enum machine_mode inner_mode;
2002       tree inner_type;
2003
2004       if (mode == TYPE_MODE (complex_float_type_node))
2005         return complex_float_type_node;
2006       if (mode == TYPE_MODE (complex_double_type_node))
2007         return complex_double_type_node;
2008       if (mode == TYPE_MODE (complex_long_double_type_node))
2009         return complex_long_double_type_node;
2010
2011       if (mode == TYPE_MODE (complex_integer_type_node) && !unsignedp)
2012         return complex_integer_type_node;
2013
2014       inner_mode = GET_MODE_INNER (mode);
2015       inner_type = c_common_type_for_mode (inner_mode, unsignedp);
2016       if (inner_type != NULL_TREE)
2017         return build_complex_type (inner_type);
2018     }
2019   else if (VECTOR_MODE_P (mode))
2020     {
2021       enum machine_mode inner_mode = GET_MODE_INNER (mode);
2022       tree inner_type = c_common_type_for_mode (inner_mode, unsignedp);
2023       if (inner_type != NULL_TREE)
2024         return build_vector_type_for_mode (inner_type, mode);
2025     }
2026
2027   if (mode == TYPE_MODE (dfloat32_type_node))
2028     return dfloat32_type_node;
2029   if (mode == TYPE_MODE (dfloat64_type_node))
2030     return dfloat64_type_node;
2031   if (mode == TYPE_MODE (dfloat128_type_node))
2032     return dfloat128_type_node;
2033
2034   for (t = registered_builtin_types; t; t = TREE_CHAIN (t))
2035     if (TYPE_MODE (TREE_VALUE (t)) == mode)
2036       return TREE_VALUE (t);
2037
2038   return 0;
2039 }
2040
2041 /* Return a signed type the same as TYPE in other respects.  */
2042
2043 tree
2044 c_common_signed_type (tree type)
2045 {
2046   tree type1 = TYPE_MAIN_VARIANT (type);
2047   if (type1 == unsigned_char_type_node || type1 == char_type_node)
2048     return signed_char_type_node;
2049   if (type1 == unsigned_type_node)
2050     return integer_type_node;
2051   if (type1 == short_unsigned_type_node)
2052     return short_integer_type_node;
2053   if (type1 == long_unsigned_type_node)
2054     return long_integer_type_node;
2055   if (type1 == long_long_unsigned_type_node)
2056     return long_long_integer_type_node;
2057   if (type1 == widest_unsigned_literal_type_node)
2058     return widest_integer_literal_type_node;
2059 #if HOST_BITS_PER_WIDE_INT >= 64
2060   if (type1 == unsigned_intTI_type_node)
2061     return intTI_type_node;
2062 #endif
2063   if (type1 == unsigned_intDI_type_node)
2064     return intDI_type_node;
2065   if (type1 == unsigned_intSI_type_node)
2066     return intSI_type_node;
2067   if (type1 == unsigned_intHI_type_node)
2068     return intHI_type_node;
2069   if (type1 == unsigned_intQI_type_node)
2070     return intQI_type_node;
2071
2072   return c_common_signed_or_unsigned_type (0, type);
2073 }
2074
2075 /* Return a type the same as TYPE except unsigned or
2076    signed according to UNSIGNEDP.  */
2077
2078 tree
2079 c_common_signed_or_unsigned_type (int unsignedp, tree type)
2080 {
2081   tree type1;
2082
2083   /* This block of code emulates the behavior of the old
2084      c_common_unsigned_type. In particular, it returns
2085      long_unsigned_type_node if passed a long, even when a int would
2086      have the same size. This is necessary for warnings to work
2087      correctly in archs where sizeof(int) == sizeof(long) */
2088
2089   type1 = TYPE_MAIN_VARIANT (type);
2090   if (type1 == signed_char_type_node || type1 == char_type_node || type1 == unsigned_char_type_node)
2091     return unsignedp ? unsigned_char_type_node : signed_char_type_node;
2092   if (type1 == integer_type_node || type1 == unsigned_type_node)
2093     return unsignedp ? unsigned_type_node : integer_type_node;
2094   if (type1 == short_integer_type_node || type1 == short_unsigned_type_node)
2095     return unsignedp ? short_unsigned_type_node : short_integer_type_node;
2096   if (type1 == long_integer_type_node || type1 == long_unsigned_type_node)
2097     return unsignedp ? long_unsigned_type_node : long_integer_type_node;
2098   if (type1 == long_long_integer_type_node || type1 == long_long_unsigned_type_node)
2099     return unsignedp ? long_long_unsigned_type_node : long_long_integer_type_node;
2100   if (type1 == widest_integer_literal_type_node || type1 == widest_unsigned_literal_type_node)
2101     return unsignedp ? widest_unsigned_literal_type_node : widest_integer_literal_type_node;
2102 #if HOST_BITS_PER_WIDE_INT >= 64
2103   if (type1 == intTI_type_node || type1 == unsigned_intTI_type_node)
2104     return unsignedp ? unsigned_intTI_type_node : intTI_type_node;
2105 #endif
2106   if (type1 == intDI_type_node || type1 == unsigned_intDI_type_node)
2107     return unsignedp ? unsigned_intDI_type_node : intDI_type_node;
2108   if (type1 == intSI_type_node || type1 == unsigned_intSI_type_node)
2109     return unsignedp ? unsigned_intSI_type_node : intSI_type_node;
2110   if (type1 == intHI_type_node || type1 == unsigned_intHI_type_node)
2111     return unsignedp ? unsigned_intHI_type_node : intHI_type_node;
2112   if (type1 == intQI_type_node || type1 == unsigned_intQI_type_node)
2113     return unsignedp ? unsigned_intQI_type_node : intQI_type_node;
2114
2115   /* For ENUMERAL_TYPEs in C++, must check the mode of the types, not
2116      the precision; they have precision set to match their range, but
2117      may use a wider mode to match an ABI.  If we change modes, we may
2118      wind up with bad conversions.  For INTEGER_TYPEs in C, must check
2119      the precision as well, so as to yield correct results for
2120      bit-field types.  C++ does not have these separate bit-field
2121      types, and producing a signed or unsigned variant of an
2122      ENUMERAL_TYPE may cause other problems as well.  */
2123
2124   if (!INTEGRAL_TYPE_P (type)
2125       || TYPE_UNSIGNED (type) == unsignedp)
2126     return type;
2127
2128 #define TYPE_OK(node)                                                       \
2129   (TYPE_MODE (type) == TYPE_MODE (node)                                     \
2130    && (c_dialect_cxx () || TYPE_PRECISION (type) == TYPE_PRECISION (node)))
2131   if (TYPE_OK (signed_char_type_node))
2132     return unsignedp ? unsigned_char_type_node : signed_char_type_node;
2133   if (TYPE_OK (integer_type_node))
2134     return unsignedp ? unsigned_type_node : integer_type_node;
2135   if (TYPE_OK (short_integer_type_node))
2136     return unsignedp ? short_unsigned_type_node : short_integer_type_node;
2137   if (TYPE_OK (long_integer_type_node))
2138     return unsignedp ? long_unsigned_type_node : long_integer_type_node;
2139   if (TYPE_OK (long_long_integer_type_node))
2140     return (unsignedp ? long_long_unsigned_type_node
2141             : long_long_integer_type_node);
2142   if (TYPE_OK (widest_integer_literal_type_node))
2143     return (unsignedp ? widest_unsigned_literal_type_node
2144             : widest_integer_literal_type_node);
2145
2146 #if HOST_BITS_PER_WIDE_INT >= 64
2147   if (TYPE_OK (intTI_type_node))
2148     return unsignedp ? unsigned_intTI_type_node : intTI_type_node;
2149 #endif
2150   if (TYPE_OK (intDI_type_node))
2151     return unsignedp ? unsigned_intDI_type_node : intDI_type_node;
2152   if (TYPE_OK (intSI_type_node))
2153     return unsignedp ? unsigned_intSI_type_node : intSI_type_node;
2154   if (TYPE_OK (intHI_type_node))
2155     return unsignedp ? unsigned_intHI_type_node : intHI_type_node;
2156   if (TYPE_OK (intQI_type_node))
2157     return unsignedp ? unsigned_intQI_type_node : intQI_type_node;
2158 #undef TYPE_OK
2159
2160   if (c_dialect_cxx ())
2161     return type;
2162   else
2163     return build_nonstandard_integer_type (TYPE_PRECISION (type), unsignedp);
2164 }
2165
2166 /* Build a bit-field integer type for the given WIDTH and UNSIGNEDP.  */
2167
2168 tree
2169 c_build_bitfield_integer_type (unsigned HOST_WIDE_INT width, int unsignedp)
2170 {
2171   /* Extended integer types of the same width as a standard type have
2172      lesser rank, so those of the same width as int promote to int or
2173      unsigned int and are valid for printf formats expecting int or
2174      unsigned int.  To avoid such special cases, avoid creating
2175      extended integer types for bit-fields if a standard integer type
2176      is available.  */
2177   if (width == TYPE_PRECISION (integer_type_node))
2178     return unsignedp ? unsigned_type_node : integer_type_node;
2179   if (width == TYPE_PRECISION (signed_char_type_node))
2180     return unsignedp ? unsigned_char_type_node : signed_char_type_node;
2181   if (width == TYPE_PRECISION (short_integer_type_node))
2182     return unsignedp ? short_unsigned_type_node : short_integer_type_node;
2183   if (width == TYPE_PRECISION (long_integer_type_node))
2184     return unsignedp ? long_unsigned_type_node : long_integer_type_node;
2185   if (width == TYPE_PRECISION (long_long_integer_type_node))
2186     return (unsignedp ? long_long_unsigned_type_node
2187             : long_long_integer_type_node);
2188   return build_nonstandard_integer_type (width, unsignedp);
2189 }
2190
2191 /* The C version of the register_builtin_type langhook.  */
2192
2193 void
2194 c_register_builtin_type (tree type, const char* name)
2195 {
2196   tree decl;
2197
2198   decl = build_decl (TYPE_DECL, get_identifier (name), type);
2199   DECL_ARTIFICIAL (decl) = 1;
2200   if (!TYPE_NAME (type))
2201     TYPE_NAME (type) = decl;
2202   pushdecl (decl);
2203
2204   registered_builtin_types = tree_cons (0, type, registered_builtin_types);
2205 }
2206
2207 \f
2208 /* Return the minimum number of bits needed to represent VALUE in a
2209    signed or unsigned type, UNSIGNEDP says which.  */
2210
2211 unsigned int
2212 min_precision (tree value, int unsignedp)
2213 {
2214   int log;
2215
2216   /* If the value is negative, compute its negative minus 1.  The latter
2217      adjustment is because the absolute value of the largest negative value
2218      is one larger than the largest positive value.  This is equivalent to
2219      a bit-wise negation, so use that operation instead.  */
2220
2221   if (tree_int_cst_sgn (value) < 0)
2222     value = fold_build1 (BIT_NOT_EXPR, TREE_TYPE (value), value);
2223
2224   /* Return the number of bits needed, taking into account the fact
2225      that we need one more bit for a signed than unsigned type.  */
2226
2227   if (integer_zerop (value))
2228     log = 0;
2229   else
2230     log = tree_floor_log2 (value);
2231
2232   return log + 1 + !unsignedp;
2233 }
2234 \f
2235 /* Print an error message for invalid operands to arith operation
2236    CODE.  */
2237
2238 void
2239 binary_op_error (enum tree_code code)
2240 {
2241   const char *opname;
2242
2243   switch (code)
2244     {
2245     case PLUS_EXPR:
2246       opname = "+"; break;
2247     case MINUS_EXPR:
2248       opname = "-"; break;
2249     case MULT_EXPR:
2250       opname = "*"; break;
2251     case MAX_EXPR:
2252       opname = "max"; break;
2253     case MIN_EXPR:
2254       opname = "min"; break;
2255     case EQ_EXPR:
2256       opname = "=="; break;
2257     case NE_EXPR:
2258       opname = "!="; break;
2259     case LE_EXPR:
2260       opname = "<="; break;
2261     case GE_EXPR:
2262       opname = ">="; break;
2263     case LT_EXPR:
2264       opname = "<"; break;
2265     case GT_EXPR:
2266       opname = ">"; break;
2267     case LSHIFT_EXPR:
2268       opname = "<<"; break;
2269     case RSHIFT_EXPR:
2270       opname = ">>"; break;
2271     case TRUNC_MOD_EXPR:
2272     case FLOOR_MOD_EXPR:
2273       opname = "%"; break;
2274     case TRUNC_DIV_EXPR:
2275     case FLOOR_DIV_EXPR:
2276       opname = "/"; break;
2277     case BIT_AND_EXPR:
2278       opname = "&"; break;
2279     case BIT_IOR_EXPR:
2280       opname = "|"; break;
2281     case TRUTH_ANDIF_EXPR:
2282       opname = "&&"; break;
2283     case TRUTH_ORIF_EXPR:
2284       opname = "||"; break;
2285     case BIT_XOR_EXPR:
2286       opname = "^"; break;
2287     default:
2288       gcc_unreachable ();
2289     }
2290   error ("invalid operands to binary %s", opname);
2291 }
2292 \f
2293 /* Subroutine of build_binary_op, used for comparison operations.
2294    See if the operands have both been converted from subword integer types
2295    and, if so, perhaps change them both back to their original type.
2296    This function is also responsible for converting the two operands
2297    to the proper common type for comparison.
2298
2299    The arguments of this function are all pointers to local variables
2300    of build_binary_op: OP0_PTR is &OP0, OP1_PTR is &OP1,
2301    RESTYPE_PTR is &RESULT_TYPE and RESCODE_PTR is &RESULTCODE.
2302
2303    If this function returns nonzero, it means that the comparison has
2304    a constant value.  What this function returns is an expression for
2305    that value.  */
2306
2307 tree
2308 shorten_compare (tree *op0_ptr, tree *op1_ptr, tree *restype_ptr,
2309                  enum tree_code *rescode_ptr)
2310 {
2311   tree type;
2312   tree op0 = *op0_ptr;
2313   tree op1 = *op1_ptr;
2314   int unsignedp0, unsignedp1;
2315   int real1, real2;
2316   tree primop0, primop1;
2317   enum tree_code code = *rescode_ptr;
2318
2319   /* Throw away any conversions to wider types
2320      already present in the operands.  */
2321
2322   primop0 = get_narrower (op0, &unsignedp0);
2323   primop1 = get_narrower (op1, &unsignedp1);
2324
2325   /* Handle the case that OP0 does not *contain* a conversion
2326      but it *requires* conversion to FINAL_TYPE.  */
2327
2328   if (op0 == primop0 && TREE_TYPE (op0) != *restype_ptr)
2329     unsignedp0 = TYPE_UNSIGNED (TREE_TYPE (op0));
2330   if (op1 == primop1 && TREE_TYPE (op1) != *restype_ptr)
2331     unsignedp1 = TYPE_UNSIGNED (TREE_TYPE (op1));
2332
2333   /* If one of the operands must be floated, we cannot optimize.  */
2334   real1 = TREE_CODE (TREE_TYPE (primop0)) == REAL_TYPE;
2335   real2 = TREE_CODE (TREE_TYPE (primop1)) == REAL_TYPE;
2336
2337   /* If first arg is constant, swap the args (changing operation
2338      so value is preserved), for canonicalization.  Don't do this if
2339      the second arg is 0.  */
2340
2341   if (TREE_CONSTANT (primop0)
2342       && !integer_zerop (primop1) && !real_zerop (primop1))
2343     {
2344       tree tem = primop0;
2345       int temi = unsignedp0;
2346       primop0 = primop1;
2347       primop1 = tem;
2348       tem = op0;
2349       op0 = op1;
2350       op1 = tem;
2351       *op0_ptr = op0;
2352       *op1_ptr = op1;
2353       unsignedp0 = unsignedp1;
2354       unsignedp1 = temi;
2355       temi = real1;
2356       real1 = real2;
2357       real2 = temi;
2358
2359       switch (code)
2360         {
2361         case LT_EXPR:
2362           code = GT_EXPR;
2363           break;
2364         case GT_EXPR:
2365           code = LT_EXPR;
2366           break;
2367         case LE_EXPR:
2368           code = GE_EXPR;
2369           break;
2370         case GE_EXPR:
2371           code = LE_EXPR;
2372           break;
2373         default:
2374           break;
2375         }
2376       *rescode_ptr = code;
2377     }
2378
2379   /* If comparing an integer against a constant more bits wide,
2380      maybe we can deduce a value of 1 or 0 independent of the data.
2381      Or else truncate the constant now
2382      rather than extend the variable at run time.
2383
2384      This is only interesting if the constant is the wider arg.
2385      Also, it is not safe if the constant is unsigned and the
2386      variable arg is signed, since in this case the variable
2387      would be sign-extended and then regarded as unsigned.
2388      Our technique fails in this case because the lowest/highest
2389      possible unsigned results don't follow naturally from the
2390      lowest/highest possible values of the variable operand.
2391      For just EQ_EXPR and NE_EXPR there is another technique that
2392      could be used: see if the constant can be faithfully represented
2393      in the other operand's type, by truncating it and reextending it
2394      and see if that preserves the constant's value.  */
2395
2396   if (!real1 && !real2
2397       && TREE_CODE (primop1) == INTEGER_CST
2398       && TYPE_PRECISION (TREE_TYPE (primop0)) < TYPE_PRECISION (*restype_ptr))
2399     {
2400       int min_gt, max_gt, min_lt, max_lt;
2401       tree maxval, minval;
2402       /* 1 if comparison is nominally unsigned.  */
2403       int unsignedp = TYPE_UNSIGNED (*restype_ptr);
2404       tree val;
2405
2406       type = c_common_signed_or_unsigned_type (unsignedp0,
2407                                                TREE_TYPE (primop0));
2408
2409       maxval = TYPE_MAX_VALUE (type);
2410       minval = TYPE_MIN_VALUE (type);
2411
2412       if (unsignedp && !unsignedp0)
2413         *restype_ptr = c_common_signed_type (*restype_ptr);
2414
2415       if (TREE_TYPE (primop1) != *restype_ptr)
2416         {
2417           /* Convert primop1 to target type, but do not introduce
2418              additional overflow.  We know primop1 is an int_cst.  */
2419           primop1 = force_fit_type_double (*restype_ptr,
2420                                            TREE_INT_CST_LOW (primop1),
2421                                            TREE_INT_CST_HIGH (primop1), 0,
2422                                            TREE_OVERFLOW (primop1));
2423         }
2424       if (type != *restype_ptr)
2425         {
2426           minval = convert (*restype_ptr, minval);
2427           maxval = convert (*restype_ptr, maxval);
2428         }
2429
2430       if (unsignedp && unsignedp0)
2431         {
2432           min_gt = INT_CST_LT_UNSIGNED (primop1, minval);
2433           max_gt = INT_CST_LT_UNSIGNED (primop1, maxval);
2434           min_lt = INT_CST_LT_UNSIGNED (minval, primop1);
2435           max_lt = INT_CST_LT_UNSIGNED (maxval, primop1);
2436         }
2437       else
2438         {
2439           min_gt = INT_CST_LT (primop1, minval);
2440           max_gt = INT_CST_LT (primop1, maxval);
2441           min_lt = INT_CST_LT (minval, primop1);
2442           max_lt = INT_CST_LT (maxval, primop1);
2443         }
2444
2445       val = 0;
2446       /* This used to be a switch, but Genix compiler can't handle that.  */
2447       if (code == NE_EXPR)
2448         {
2449           if (max_lt || min_gt)
2450             val = truthvalue_true_node;
2451         }
2452       else if (code == EQ_EXPR)
2453         {
2454           if (max_lt || min_gt)
2455             val = truthvalue_false_node;
2456         }
2457       else if (code == LT_EXPR)
2458         {
2459           if (max_lt)
2460             val = truthvalue_true_node;
2461           if (!min_lt)
2462             val = truthvalue_false_node;
2463         }
2464       else if (code == GT_EXPR)
2465         {
2466           if (min_gt)
2467             val = truthvalue_true_node;
2468           if (!max_gt)
2469             val = truthvalue_false_node;
2470         }
2471       else if (code == LE_EXPR)
2472         {
2473           if (!max_gt)
2474             val = truthvalue_true_node;
2475           if (min_gt)
2476             val = truthvalue_false_node;
2477         }
2478       else if (code == GE_EXPR)
2479         {
2480           if (!min_lt)
2481             val = truthvalue_true_node;
2482           if (max_lt)
2483             val = truthvalue_false_node;
2484         }
2485
2486       /* If primop0 was sign-extended and unsigned comparison specd,
2487          we did a signed comparison above using the signed type bounds.
2488          But the comparison we output must be unsigned.
2489
2490          Also, for inequalities, VAL is no good; but if the signed
2491          comparison had *any* fixed result, it follows that the
2492          unsigned comparison just tests the sign in reverse
2493          (positive values are LE, negative ones GE).
2494          So we can generate an unsigned comparison
2495          against an extreme value of the signed type.  */
2496
2497       if (unsignedp && !unsignedp0)
2498         {
2499           if (val != 0)
2500             switch (code)
2501               {
2502               case LT_EXPR:
2503               case GE_EXPR:
2504                 primop1 = TYPE_MIN_VALUE (type);
2505                 val = 0;
2506                 break;
2507
2508               case LE_EXPR:
2509               case GT_EXPR:
2510                 primop1 = TYPE_MAX_VALUE (type);
2511                 val = 0;
2512                 break;
2513
2514               default:
2515                 break;
2516               }
2517           /* unsigned_type_for doesn't support C bit fields */
2518           type = c_common_signed_or_unsigned_type (1, type);
2519         }
2520
2521       if (TREE_CODE (primop0) != INTEGER_CST)
2522         {
2523           if (val == truthvalue_false_node)
2524             warning (OPT_Wtype_limits, "comparison is always false due to limited range of data type");
2525           if (val == truthvalue_true_node)
2526             warning (OPT_Wtype_limits, "comparison is always true due to limited range of data type");
2527         }
2528
2529       if (val != 0)
2530         {
2531           /* Don't forget to evaluate PRIMOP0 if it has side effects.  */
2532           if (TREE_SIDE_EFFECTS (primop0))
2533             return build2 (COMPOUND_EXPR, TREE_TYPE (val), primop0, val);
2534           return val;
2535         }
2536
2537       /* Value is not predetermined, but do the comparison
2538          in the type of the operand that is not constant.
2539          TYPE is already properly set.  */
2540     }
2541
2542   /* If either arg is decimal float and the other is float, find the
2543      proper common type to use for comparison.  */
2544   else if (real1 && real2
2545            && (DECIMAL_FLOAT_MODE_P (TYPE_MODE (TREE_TYPE (primop0)))
2546                || DECIMAL_FLOAT_MODE_P (TYPE_MODE (TREE_TYPE (primop1)))))
2547     type = common_type (TREE_TYPE (primop0), TREE_TYPE (primop1));
2548
2549   else if (real1 && real2
2550            && (TYPE_PRECISION (TREE_TYPE (primop0))
2551                == TYPE_PRECISION (TREE_TYPE (primop1))))
2552     type = TREE_TYPE (primop0);
2553
2554   /* If args' natural types are both narrower than nominal type
2555      and both extend in the same manner, compare them
2556      in the type of the wider arg.
2557      Otherwise must actually extend both to the nominal
2558      common type lest different ways of extending
2559      alter the result.
2560      (eg, (short)-1 == (unsigned short)-1  should be 0.)  */
2561
2562   else if (unsignedp0 == unsignedp1 && real1 == real2
2563            && TYPE_PRECISION (TREE_TYPE (primop0)) < TYPE_PRECISION (*restype_ptr)
2564            && TYPE_PRECISION (TREE_TYPE (primop1)) < TYPE_PRECISION (*restype_ptr))
2565     {
2566       type = common_type (TREE_TYPE (primop0), TREE_TYPE (primop1));
2567       type = c_common_signed_or_unsigned_type (unsignedp0
2568                                                || TYPE_UNSIGNED (*restype_ptr),
2569                                                type);
2570       /* Make sure shorter operand is extended the right way
2571          to match the longer operand.  */
2572       primop0
2573         = convert (c_common_signed_or_unsigned_type (unsignedp0,
2574                                                      TREE_TYPE (primop0)),
2575                    primop0);
2576       primop1
2577         = convert (c_common_signed_or_unsigned_type (unsignedp1,
2578                                                      TREE_TYPE (primop1)),
2579                    primop1);
2580     }
2581   else
2582     {
2583       /* Here we must do the comparison on the nominal type
2584          using the args exactly as we received them.  */
2585       type = *restype_ptr;
2586       primop0 = op0;
2587       primop1 = op1;
2588
2589       if (!real1 && !real2 && integer_zerop (primop1)
2590           && TYPE_UNSIGNED (*restype_ptr))
2591         {
2592           tree value = 0;
2593           switch (code)
2594             {
2595             case GE_EXPR:
2596               /* All unsigned values are >= 0, so we warn.  However,
2597                  if OP0 is a constant that is >= 0, the signedness of
2598                  the comparison isn't an issue, so suppress the
2599                  warning.  */
2600               if (warn_type_limits && !in_system_header
2601                   && !(TREE_CODE (primop0) == INTEGER_CST
2602                        && !TREE_OVERFLOW (convert (c_common_signed_type (type),
2603                                                    primop0))))
2604                 warning (OPT_Wtype_limits,
2605                          "comparison of unsigned expression >= 0 is always true");
2606               value = truthvalue_true_node;
2607               break;
2608
2609             case LT_EXPR:
2610               if (warn_type_limits && !in_system_header
2611                   && !(TREE_CODE (primop0) == INTEGER_CST
2612                        && !TREE_OVERFLOW (convert (c_common_signed_type (type),
2613                                                    primop0))))
2614                 warning (OPT_Wtype_limits,
2615                          "comparison of unsigned expression < 0 is always false");
2616               value = truthvalue_false_node;
2617               break;
2618
2619             default:
2620               break;
2621             }
2622
2623           if (value != 0)
2624             {
2625               /* Don't forget to evaluate PRIMOP0 if it has side effects.  */
2626               if (TREE_SIDE_EFFECTS (primop0))
2627                 return build2 (COMPOUND_EXPR, TREE_TYPE (value),
2628                                primop0, value);
2629               return value;
2630             }
2631         }
2632     }
2633
2634   *op0_ptr = convert (type, primop0);
2635   *op1_ptr = convert (type, primop1);
2636
2637   *restype_ptr = truthvalue_type_node;
2638
2639   return 0;
2640 }
2641 \f
2642 /* Return a tree for the sum or difference (RESULTCODE says which)
2643    of pointer PTROP and integer INTOP.  */
2644
2645 tree
2646 pointer_int_sum (enum tree_code resultcode, tree ptrop, tree intop)
2647 {
2648   tree size_exp, ret;
2649
2650   /* The result is a pointer of the same type that is being added.  */
2651
2652   tree result_type = TREE_TYPE (ptrop);
2653
2654   if (TREE_CODE (TREE_TYPE (result_type)) == VOID_TYPE)
2655     {
2656       if (pedantic || warn_pointer_arith)
2657         pedwarn ("pointer of type %<void *%> used in arithmetic");
2658       size_exp = integer_one_node;
2659     }
2660   else if (TREE_CODE (TREE_TYPE (result_type)) == FUNCTION_TYPE)
2661     {
2662       if (pedantic || warn_pointer_arith)
2663         pedwarn ("pointer to a function used in arithmetic");
2664       size_exp = integer_one_node;
2665     }
2666   else if (TREE_CODE (TREE_TYPE (result_type)) == METHOD_TYPE)
2667     {
2668       if (pedantic || warn_pointer_arith)
2669         pedwarn ("pointer to member function used in arithmetic");
2670       size_exp = integer_one_node;
2671     }
2672   else
2673     size_exp = size_in_bytes (TREE_TYPE (result_type));
2674
2675   /* We are manipulating pointer values, so we don't need to warn
2676      about relying on undefined signed overflow.  We disable the
2677      warning here because we use integer types so fold won't know that
2678      they are really pointers.  */
2679   fold_defer_overflow_warnings ();
2680
2681   /* If what we are about to multiply by the size of the elements
2682      contains a constant term, apply distributive law
2683      and multiply that constant term separately.
2684      This helps produce common subexpressions.  */
2685
2686   if ((TREE_CODE (intop) == PLUS_EXPR || TREE_CODE (intop) == MINUS_EXPR)
2687       && !TREE_CONSTANT (intop)
2688       && TREE_CONSTANT (TREE_OPERAND (intop, 1))
2689       && TREE_CONSTANT (size_exp)
2690       /* If the constant comes from pointer subtraction,
2691          skip this optimization--it would cause an error.  */
2692       && TREE_CODE (TREE_TYPE (TREE_OPERAND (intop, 0))) == INTEGER_TYPE
2693       /* If the constant is unsigned, and smaller than the pointer size,
2694          then we must skip this optimization.  This is because it could cause
2695          an overflow error if the constant is negative but INTOP is not.  */
2696       && (!TYPE_UNSIGNED (TREE_TYPE (intop))
2697           || (TYPE_PRECISION (TREE_TYPE (intop))
2698               == TYPE_PRECISION (TREE_TYPE (ptrop)))))
2699     {
2700       enum tree_code subcode = resultcode;
2701       tree int_type = TREE_TYPE (intop);
2702       if (TREE_CODE (intop) == MINUS_EXPR)
2703         subcode = (subcode == PLUS_EXPR ? MINUS_EXPR : PLUS_EXPR);
2704       /* Convert both subexpression types to the type of intop,
2705          because weird cases involving pointer arithmetic
2706          can result in a sum or difference with different type args.  */
2707       ptrop = build_binary_op (subcode, ptrop,
2708                                convert (int_type, TREE_OPERAND (intop, 1)), 1);
2709       intop = convert (int_type, TREE_OPERAND (intop, 0));
2710     }
2711
2712   /* Convert the integer argument to a type the same size as sizetype
2713      so the multiply won't overflow spuriously.  */
2714
2715   if (TYPE_PRECISION (TREE_TYPE (intop)) != TYPE_PRECISION (sizetype)
2716       || TYPE_UNSIGNED (TREE_TYPE (intop)) != TYPE_UNSIGNED (sizetype))
2717     intop = convert (c_common_type_for_size (TYPE_PRECISION (sizetype),
2718                                              TYPE_UNSIGNED (sizetype)), intop);
2719
2720   /* Replace the integer argument with a suitable product by the object size.
2721      Do this multiplication as signed, then convert to the appropriate
2722      pointer type (actually unsigned integral).  */
2723
2724   intop = convert (result_type,
2725                    build_binary_op (MULT_EXPR, intop,
2726                                     convert (TREE_TYPE (intop), size_exp), 1));
2727
2728   /* Create the sum or difference.  */
2729   ret = fold_build2 (resultcode, result_type, ptrop, intop);
2730
2731   fold_undefer_and_ignore_overflow_warnings ();
2732
2733   return ret;
2734 }
2735 \f
2736 /* Return whether EXPR is a declaration whose address can never be
2737    NULL.  */
2738
2739 bool
2740 decl_with_nonnull_addr_p (tree expr)
2741 {
2742   return (DECL_P (expr)
2743           && (TREE_CODE (expr) == PARM_DECL
2744               || TREE_CODE (expr) == LABEL_DECL
2745               || !DECL_WEAK (expr)));
2746 }
2747
2748 /* Prepare expr to be an argument of a TRUTH_NOT_EXPR,
2749    or for an `if' or `while' statement or ?..: exp.  It should already
2750    have been validated to be of suitable type; otherwise, a bad
2751    diagnostic may result.
2752
2753    This preparation consists of taking the ordinary
2754    representation of an expression expr and producing a valid tree
2755    boolean expression describing whether expr is nonzero.  We could
2756    simply always do build_binary_op (NE_EXPR, expr, truthvalue_false_node, 1),
2757    but we optimize comparisons, &&, ||, and !.
2758
2759    The resulting type should always be `truthvalue_type_node'.  */
2760
2761 tree
2762 c_common_truthvalue_conversion (tree expr)
2763 {
2764   switch (TREE_CODE (expr))
2765     {
2766     case EQ_EXPR:   case NE_EXPR:   case UNEQ_EXPR: case LTGT_EXPR:
2767     case LE_EXPR:   case GE_EXPR:   case LT_EXPR:   case GT_EXPR:
2768     case UNLE_EXPR: case UNGE_EXPR: case UNLT_EXPR: case UNGT_EXPR:
2769     case ORDERED_EXPR: case UNORDERED_EXPR:
2770       if (TREE_TYPE (expr) == truthvalue_type_node)
2771         return expr;
2772       return build2 (TREE_CODE (expr), truthvalue_type_node,
2773                      TREE_OPERAND (expr, 0), TREE_OPERAND (expr, 1));
2774
2775     case TRUTH_ANDIF_EXPR:
2776     case TRUTH_ORIF_EXPR:
2777     case TRUTH_AND_EXPR:
2778     case TRUTH_OR_EXPR:
2779     case TRUTH_XOR_EXPR:
2780       if (TREE_TYPE (expr) == truthvalue_type_node)
2781         return expr;
2782       return build2 (TREE_CODE (expr), truthvalue_type_node,
2783                  c_common_truthvalue_conversion (TREE_OPERAND (expr, 0)),
2784                  c_common_truthvalue_conversion (TREE_OPERAND (expr, 1)));
2785
2786     case TRUTH_NOT_EXPR:
2787       if (TREE_TYPE (expr) == truthvalue_type_node)
2788         return expr;
2789       return build1 (TREE_CODE (expr), truthvalue_type_node,
2790                  c_common_truthvalue_conversion (TREE_OPERAND (expr, 0)));
2791
2792     case ERROR_MARK:
2793       return expr;
2794
2795     case INTEGER_CST:
2796       return integer_zerop (expr) ? truthvalue_false_node
2797                                   : truthvalue_true_node;
2798
2799     case REAL_CST:
2800       return real_compare (NE_EXPR, &TREE_REAL_CST (expr), &dconst0)
2801              ? truthvalue_true_node
2802              : truthvalue_false_node;
2803
2804     case FUNCTION_DECL:
2805       expr = build_unary_op (ADDR_EXPR, expr, 0);
2806       /* Fall through.  */
2807
2808     case ADDR_EXPR:
2809       {
2810         tree inner = TREE_OPERAND (expr, 0);
2811         if (decl_with_nonnull_addr_p (inner))
2812           {
2813             /* Common Ada/Pascal programmer's mistake.  */
2814             warning (OPT_Waddress,
2815                      "the address of %qD will always evaluate as %<true%>",
2816                      inner);
2817             return truthvalue_true_node;
2818           }
2819
2820         /* If we still have a decl, it is possible for its address to
2821            be NULL, so we cannot optimize.  */
2822         if (DECL_P (inner))
2823           {
2824             gcc_assert (DECL_WEAK (inner));
2825             break;
2826           }
2827
2828         if (TREE_SIDE_EFFECTS (inner))
2829           return build2 (COMPOUND_EXPR, truthvalue_type_node,
2830                          inner, truthvalue_true_node);
2831         else
2832           return truthvalue_true_node;
2833       }
2834
2835     case COMPLEX_EXPR:
2836       return build_binary_op ((TREE_SIDE_EFFECTS (TREE_OPERAND (expr, 1))
2837                                ? TRUTH_OR_EXPR : TRUTH_ORIF_EXPR),
2838                 c_common_truthvalue_conversion (TREE_OPERAND (expr, 0)),
2839                 c_common_truthvalue_conversion (TREE_OPERAND (expr, 1)),
2840                               0);
2841
2842     case NEGATE_EXPR:
2843     case ABS_EXPR:
2844     case FLOAT_EXPR:
2845       /* These don't change whether an object is nonzero or zero.  */
2846       return c_common_truthvalue_conversion (TREE_OPERAND (expr, 0));
2847
2848     case LROTATE_EXPR:
2849     case RROTATE_EXPR:
2850       /* These don't change whether an object is zero or nonzero, but
2851          we can't ignore them if their second arg has side-effects.  */
2852       if (TREE_SIDE_EFFECTS (TREE_OPERAND (expr, 1)))
2853         return build2 (COMPOUND_EXPR, truthvalue_type_node,
2854                        TREE_OPERAND (expr, 1),
2855                        c_common_truthvalue_conversion (TREE_OPERAND (expr, 0)));
2856       else
2857         return c_common_truthvalue_conversion (TREE_OPERAND (expr, 0));
2858
2859     case COND_EXPR:
2860       /* Distribute the conversion into the arms of a COND_EXPR.  */
2861       return fold_build3 (COND_EXPR, truthvalue_type_node,
2862                 TREE_OPERAND (expr, 0),
2863                 c_common_truthvalue_conversion (TREE_OPERAND (expr, 1)),
2864                 c_common_truthvalue_conversion (TREE_OPERAND (expr, 2)));
2865
2866     case CONVERT_EXPR:
2867     case NOP_EXPR:
2868       /* Don't cancel the effect of a CONVERT_EXPR from a REFERENCE_TYPE,
2869          since that affects how `default_conversion' will behave.  */
2870       if (TREE_CODE (TREE_TYPE (expr)) == REFERENCE_TYPE
2871           || TREE_CODE (TREE_TYPE (TREE_OPERAND (expr, 0))) == REFERENCE_TYPE)
2872         break;
2873       /* If this is widening the argument, we can ignore it.  */
2874       if (TYPE_PRECISION (TREE_TYPE (expr))
2875           >= TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (expr, 0))))
2876         return c_common_truthvalue_conversion (TREE_OPERAND (expr, 0));
2877       break;
2878
2879     case MODIFY_EXPR:
2880       if (!TREE_NO_WARNING (expr)
2881           && warn_parentheses)
2882         {
2883           warning (OPT_Wparentheses,
2884                    "suggest parentheses around assignment used as truth value");
2885           TREE_NO_WARNING (expr) = 1;
2886         }
2887       break;
2888
2889     default:
2890       break;
2891     }
2892
2893   if (TREE_CODE (TREE_TYPE (expr)) == COMPLEX_TYPE)
2894     {
2895       tree t = save_expr (expr);
2896       return (build_binary_op
2897               ((TREE_SIDE_EFFECTS (expr)
2898                 ? TRUTH_OR_EXPR : TRUTH_ORIF_EXPR),
2899         c_common_truthvalue_conversion (build_unary_op (REALPART_EXPR, t, 0)),
2900         c_common_truthvalue_conversion (build_unary_op (IMAGPART_EXPR, t, 0)),
2901                0));
2902     }
2903
2904   return build_binary_op (NE_EXPR, expr, integer_zero_node, 1);
2905 }
2906 \f
2907 static void def_builtin_1  (enum built_in_function fncode,
2908                             const char *name,
2909                             enum built_in_class fnclass,
2910                             tree fntype, tree libtype,
2911                             bool both_p, bool fallback_p, bool nonansi_p,
2912                             tree fnattrs, bool implicit_p);
2913
2914 /* Make a variant type in the proper way for C/C++, propagating qualifiers
2915    down to the element type of an array.  */
2916
2917 tree
2918 c_build_qualified_type (tree type, int type_quals)
2919 {
2920   if (type == error_mark_node)
2921     return type;
2922
2923   if (TREE_CODE (type) == ARRAY_TYPE)
2924     {
2925       tree t;
2926       tree element_type = c_build_qualified_type (TREE_TYPE (type),
2927                                                   type_quals);
2928
2929       /* See if we already have an identically qualified type.  */
2930       for (t = TYPE_MAIN_VARIANT (type); t; t = TYPE_NEXT_VARIANT (t))
2931         {
2932           if (TYPE_QUALS (strip_array_types (t)) == type_quals
2933               && TYPE_NAME (t) == TYPE_NAME (type)
2934               && TYPE_CONTEXT (t) == TYPE_CONTEXT (type)
2935               && attribute_list_equal (TYPE_ATTRIBUTES (t),
2936                                        TYPE_ATTRIBUTES (type)))
2937             break;
2938         }
2939       if (!t)
2940         {
2941           tree domain = TYPE_DOMAIN (type);
2942
2943           t = build_variant_type_copy (type);
2944           TREE_TYPE (t) = element_type;
2945
2946           if (TYPE_STRUCTURAL_EQUALITY_P (element_type)
2947               || (domain && TYPE_STRUCTURAL_EQUALITY_P (domain)))
2948             SET_TYPE_STRUCTURAL_EQUALITY (t);
2949           else if (TYPE_CANONICAL (element_type) != element_type
2950                    || (domain && TYPE_CANONICAL (domain) != domain))
2951             {
2952               tree unqualified_canon
2953                 = build_array_type (TYPE_CANONICAL (element_type),
2954                                     domain? TYPE_CANONICAL (domain)
2955                                           : NULL_TREE);
2956               TYPE_CANONICAL (t)
2957                 = c_build_qualified_type (unqualified_canon, type_quals);
2958             }
2959           else
2960             TYPE_CANONICAL (t) = t;
2961         }
2962       return t;
2963     }
2964
2965   /* A restrict-qualified pointer type must be a pointer to object or
2966      incomplete type.  Note that the use of POINTER_TYPE_P also allows
2967      REFERENCE_TYPEs, which is appropriate for C++.  */
2968   if ((type_quals & TYPE_QUAL_RESTRICT)
2969       && (!POINTER_TYPE_P (type)
2970           || !C_TYPE_OBJECT_OR_INCOMPLETE_P (TREE_TYPE (type))))
2971     {
2972       error ("invalid use of %<restrict%>");
2973       type_quals &= ~TYPE_QUAL_RESTRICT;
2974     }
2975
2976   return build_qualified_type (type, type_quals);
2977 }
2978
2979 /* Apply the TYPE_QUALS to the new DECL.  */
2980
2981 void
2982 c_apply_type_quals_to_decl (int type_quals, tree decl)
2983 {
2984   tree type = TREE_TYPE (decl);
2985
2986   if (type == error_mark_node)
2987     return;
2988
2989   if (((type_quals & TYPE_QUAL_CONST)
2990        || (type && TREE_CODE (type) == REFERENCE_TYPE))
2991       /* An object declared 'const' is only readonly after it is
2992          initialized.  We don't have any way of expressing this currently,
2993          so we need to be conservative and unset TREE_READONLY for types
2994          with constructors.  Otherwise aliasing code will ignore stores in
2995          an inline constructor.  */
2996       && !(type && TYPE_NEEDS_CONSTRUCTING (type)))
2997     TREE_READONLY (decl) = 1;
2998   if (type_quals & TYPE_QUAL_VOLATILE)
2999     {
3000       TREE_SIDE_EFFECTS (decl) = 1;
3001       TREE_THIS_VOLATILE (decl) = 1;
3002     }
3003   if (type_quals & TYPE_QUAL_RESTRICT)
3004     {
3005       while (type && TREE_CODE (type) == ARRAY_TYPE)
3006         /* Allow 'restrict' on arrays of pointers.
3007            FIXME currently we just ignore it.  */
3008         type = TREE_TYPE (type);
3009       if (!type
3010           || !POINTER_TYPE_P (type)
3011           || !C_TYPE_OBJECT_OR_INCOMPLETE_P (TREE_TYPE (type)))
3012         error ("invalid use of %<restrict%>");
3013       else if (flag_strict_aliasing && type == TREE_TYPE (decl))
3014         /* Indicate we need to make a unique alias set for this pointer.
3015            We can't do it here because it might be pointing to an
3016            incomplete type.  */
3017         DECL_POINTER_ALIAS_SET (decl) = -2;
3018     }
3019 }
3020
3021 /* Hash function for the problem of multiple type definitions in
3022    different files.  This must hash all types that will compare
3023    equal via comptypes to the same value.  In practice it hashes
3024    on some of the simple stuff and leaves the details to comptypes.  */
3025
3026 static hashval_t
3027 c_type_hash (const void *p)
3028 {
3029   int i = 0;
3030   int shift, size;
3031   tree t = (tree) p;
3032   tree t2;
3033   switch (TREE_CODE (t))
3034     {
3035     /* For pointers, hash on pointee type plus some swizzling.  */
3036     case POINTER_TYPE:
3037       return c_type_hash (TREE_TYPE (t)) ^ 0x3003003;
3038     /* Hash on number of elements and total size.  */
3039     case ENUMERAL_TYPE:
3040       shift = 3;
3041       t2 = TYPE_VALUES (t);
3042       break;
3043     case RECORD_TYPE:
3044       shift = 0;
3045       t2 = TYPE_FIELDS (t);
3046       break;
3047     case QUAL_UNION_TYPE:
3048       shift = 1;
3049       t2 = TYPE_FIELDS (t);
3050       break;
3051     case UNION_TYPE:
3052       shift = 2;
3053       t2 = TYPE_FIELDS (t);
3054       break;
3055     default:
3056       gcc_unreachable ();
3057     }
3058   for (; t2; t2 = TREE_CHAIN (t2))
3059     i++;
3060   size = TREE_INT_CST_LOW (TYPE_SIZE (t));
3061   return ((size << 24) | (i << shift));
3062 }
3063
3064 static GTY((param_is (union tree_node))) htab_t type_hash_table;
3065
3066 /* Return the typed-based alias set for T, which may be an expression
3067    or a type.  Return -1 if we don't do anything special.  */
3068
3069 HOST_WIDE_INT
3070 c_common_get_alias_set (tree t)
3071 {
3072   tree u;
3073   PTR *slot;
3074
3075   /* Permit type-punning when accessing a union, provided the access
3076      is directly through the union.  For example, this code does not
3077      permit taking the address of a union member and then storing
3078      through it.  Even the type-punning allowed here is a GCC
3079      extension, albeit a common and useful one; the C standard says
3080      that such accesses have implementation-defined behavior.  */
3081   for (u = t;
3082        TREE_CODE (u) == COMPONENT_REF || TREE_CODE (u) == ARRAY_REF;
3083        u = TREE_OPERAND (u, 0))
3084     if (TREE_CODE (u) == COMPONENT_REF
3085         && TREE_CODE (TREE_TYPE (TREE_OPERAND (u, 0))) == UNION_TYPE)
3086       return 0;
3087
3088   /* That's all the expressions we handle specially.  */
3089   if (!TYPE_P (t))
3090     return -1;
3091
3092   /* The C standard guarantees that any object may be accessed via an
3093      lvalue that has character type.  */
3094   if (t == char_type_node
3095       || t == signed_char_type_node
3096       || t == unsigned_char_type_node)
3097     return 0;
3098
3099   /* If it has the may_alias attribute, it can alias anything.  */
3100   if (lookup_attribute ("may_alias", TYPE_ATTRIBUTES (t)))
3101     return 0;
3102
3103   /* The C standard specifically allows aliasing between signed and
3104      unsigned variants of the same type.  We treat the signed
3105      variant as canonical.  */
3106   if (TREE_CODE (t) == INTEGER_TYPE && TYPE_UNSIGNED (t))
3107     {
3108       tree t1 = c_common_signed_type (t);
3109
3110       /* t1 == t can happen for boolean nodes which are always unsigned.  */
3111       if (t1 != t)
3112         return get_alias_set (t1);
3113     }
3114   else if (POINTER_TYPE_P (t))
3115     {
3116       tree t1;
3117
3118       /* Unfortunately, there is no canonical form of a pointer type.
3119          In particular, if we have `typedef int I', then `int *', and
3120          `I *' are different types.  So, we have to pick a canonical
3121          representative.  We do this below.
3122
3123          Technically, this approach is actually more conservative that
3124          it needs to be.  In particular, `const int *' and `int *'
3125          should be in different alias sets, according to the C and C++
3126          standard, since their types are not the same, and so,
3127          technically, an `int **' and `const int **' cannot point at
3128          the same thing.
3129
3130          But, the standard is wrong.  In particular, this code is
3131          legal C++:
3132
3133             int *ip;
3134             int **ipp = &ip;
3135             const int* const* cipp = ipp;
3136
3137          And, it doesn't make sense for that to be legal unless you
3138          can dereference IPP and CIPP.  So, we ignore cv-qualifiers on
3139          the pointed-to types.  This issue has been reported to the
3140          C++ committee.  */
3141       t1 = build_type_no_quals (t);
3142       if (t1 != t)
3143         return get_alias_set (t1);
3144     }
3145
3146   /* Handle the case of multiple type nodes referring to "the same" type,
3147      which occurs with IMA.  These share an alias set.  FIXME:  Currently only
3148      C90 is handled.  (In C99 type compatibility is not transitive, which
3149      complicates things mightily. The alias set splay trees can theoretically
3150      represent this, but insertion is tricky when you consider all the
3151      different orders things might arrive in.) */
3152
3153   if (c_language != clk_c || flag_isoc99)
3154     return -1;
3155
3156   /* Save time if there's only one input file.  */
3157   if (num_in_fnames == 1)
3158     return -1;
3159
3160   /* Pointers need special handling if they point to any type that
3161      needs special handling (below).  */
3162   if (TREE_CODE (t) == POINTER_TYPE)
3163     {
3164       tree t2;
3165       /* Find bottom type under any nested POINTERs.  */
3166       for (t2 = TREE_TYPE (t);
3167      TREE_CODE (t2) == POINTER_TYPE;
3168      t2 = TREE_TYPE (t2))
3169   ;
3170       if (TREE_CODE (t2) != RECORD_TYPE
3171     && TREE_CODE (t2) != ENUMERAL_TYPE
3172     && TREE_CODE (t2) != QUAL_UNION_TYPE
3173     && TREE_CODE (t2) != UNION_TYPE)
3174   return -1;
3175       if (TYPE_SIZE (t2) == 0)
3176   return -1;
3177     }
3178   /* These are the only cases that need special handling.  */
3179   if (TREE_CODE (t) != RECORD_TYPE
3180       && TREE_CODE (t) != ENUMERAL_TYPE
3181       && TREE_CODE (t) != QUAL_UNION_TYPE
3182       && TREE_CODE (t) != UNION_TYPE
3183       && TREE_CODE (t) != POINTER_TYPE)
3184     return -1;
3185   /* Undefined? */
3186   if (TYPE_SIZE (t) == 0)
3187     return -1;
3188
3189   /* Look up t in hash table.  Only one of the compatible types within each
3190      alias set is recorded in the table.  */
3191   if (!type_hash_table)
3192     type_hash_table = htab_create_ggc (1021, c_type_hash,
3193             (htab_eq) lang_hooks.types_compatible_p,
3194             NULL);
3195   slot = htab_find_slot (type_hash_table, t, INSERT);
3196   if (*slot != NULL)
3197     {
3198       TYPE_ALIAS_SET (t) = TYPE_ALIAS_SET ((tree)*slot);
3199       return TYPE_ALIAS_SET ((tree)*slot);
3200     }
3201   else
3202     /* Our caller will assign and record (in t) a new alias set; all we need
3203        to do is remember t in the hash table.  */
3204     *slot = t;
3205
3206   return -1;
3207 }
3208 \f
3209 /* Compute the value of 'sizeof (TYPE)' or '__alignof__ (TYPE)', where the
3210    second parameter indicates which OPERATOR is being applied.  The COMPLAIN
3211    flag controls whether we should diagnose possibly ill-formed
3212    constructs or not.  */
3213
3214 tree
3215 c_sizeof_or_alignof_type (tree type, bool is_sizeof, int complain)
3216 {
3217   const char *op_name;
3218   tree value = NULL;
3219   enum tree_code type_code = TREE_CODE (type);
3220
3221   op_name = is_sizeof ? "sizeof" : "__alignof__";
3222
3223   if (type_code == FUNCTION_TYPE)
3224     {
3225       if (is_sizeof)
3226         {
3227           if (complain && (pedantic || warn_pointer_arith))
3228             pedwarn ("invalid application of %<sizeof%> to a function type");
3229           value = size_one_node;
3230         }
3231       else
3232         value = size_int (FUNCTION_BOUNDARY / BITS_PER_UNIT);
3233     }
3234   else if (type_code == VOID_TYPE || type_code == ERROR_MARK)
3235     {
3236       if (type_code == VOID_TYPE
3237           && complain && (pedantic || warn_pointer_arith))
3238         pedwarn ("invalid application of %qs to a void type", op_name);
3239       value = size_one_node;
3240     }
3241   else if (!COMPLETE_TYPE_P (type))
3242     {
3243       if (complain)
3244         error ("invalid application of %qs to incomplete type %qT ",
3245                op_name, type);
3246       value = size_zero_node;
3247     }
3248   else
3249     {
3250       if (is_sizeof)
3251         /* Convert in case a char is more than one unit.  */
3252         value = size_binop (CEIL_DIV_EXPR, TYPE_SIZE_UNIT (type),
3253                             size_int (TYPE_PRECISION (char_type_node)
3254                                       / BITS_PER_UNIT));
3255       else
3256         value = size_int (TYPE_ALIGN_UNIT (type));
3257     }
3258
3259   /* VALUE will have an integer type with TYPE_IS_SIZETYPE set.
3260      TYPE_IS_SIZETYPE means that certain things (like overflow) will
3261      never happen.  However, this node should really have type
3262      `size_t', which is just a typedef for an ordinary integer type.  */
3263   value = fold_convert (size_type_node, value);
3264   gcc_assert (!TYPE_IS_SIZETYPE (TREE_TYPE (value)));
3265
3266   return value;
3267 }
3268
3269 /* Implement the __alignof keyword: Return the minimum required
3270    alignment of EXPR, measured in bytes.  For VAR_DECL's and
3271    FIELD_DECL's return DECL_ALIGN (which can be set from an
3272    "aligned" __attribute__ specification).  */
3273
3274 tree
3275 c_alignof_expr (tree expr)
3276 {
3277   tree t;
3278
3279   if (TREE_CODE (expr) == VAR_DECL)
3280     t = size_int (DECL_ALIGN_UNIT (expr));
3281
3282   else if (TREE_CODE (expr) == COMPONENT_REF
3283            && DECL_C_BIT_FIELD (TREE_OPERAND (expr, 1)))
3284     {
3285       error ("%<__alignof%> applied to a bit-field");
3286       t = size_one_node;
3287     }
3288   else if (TREE_CODE (expr) == COMPONENT_REF
3289            && TREE_CODE (TREE_OPERAND (expr, 1)) == FIELD_DECL)
3290     t = size_int (DECL_ALIGN_UNIT (TREE_OPERAND (expr, 1)));
3291
3292   else if (TREE_CODE (expr) == INDIRECT_REF)
3293     {
3294       tree t = TREE_OPERAND (expr, 0);
3295       tree best = t;
3296       int bestalign = TYPE_ALIGN (TREE_TYPE (TREE_TYPE (t)));
3297
3298       while ((TREE_CODE (t) == NOP_EXPR || TREE_CODE (t) == CONVERT_EXPR)
3299              && TREE_CODE (TREE_TYPE (TREE_OPERAND (t, 0))) == POINTER_TYPE)
3300         {
3301           int thisalign;
3302
3303           t = TREE_OPERAND (t, 0);
3304           thisalign = TYPE_ALIGN (TREE_TYPE (TREE_TYPE (t)));
3305           if (thisalign > bestalign)
3306             best = t, bestalign = thisalign;
3307         }
3308       return c_alignof (TREE_TYPE (TREE_TYPE (best)));
3309     }
3310   else
3311     return c_alignof (TREE_TYPE (expr));
3312
3313   return fold_convert (size_type_node, t);
3314 }
3315 \f
3316 /* Handle C and C++ default attributes.  */
3317
3318 enum built_in_attribute
3319 {
3320 #define DEF_ATTR_NULL_TREE(ENUM) ENUM,
3321 #define DEF_ATTR_INT(ENUM, VALUE) ENUM,
3322 #define DEF_ATTR_IDENT(ENUM, STRING) ENUM,
3323 #define DEF_ATTR_TREE_LIST(ENUM, PURPOSE, VALUE, CHAIN) ENUM,
3324 #include "builtin-attrs.def"
3325 #undef DEF_ATTR_NULL_TREE
3326 #undef DEF_ATTR_INT
3327 #undef DEF_ATTR_IDENT
3328 #undef DEF_ATTR_TREE_LIST
3329   ATTR_LAST
3330 };
3331
3332 static GTY(()) tree built_in_attributes[(int) ATTR_LAST];
3333
3334 static void c_init_attributes (void);
3335
3336 enum c_builtin_type
3337 {
3338 #define DEF_PRIMITIVE_TYPE(NAME, VALUE) NAME,
3339 #define DEF_FUNCTION_TYPE_0(NAME, RETURN) NAME,
3340 #define DEF_FUNCTION_TYPE_1(NAME, RETURN, ARG1) NAME,
3341 #define DEF_FUNCTION_TYPE_2(NAME, RETURN, ARG1, ARG2) NAME,
3342 #define DEF_FUNCTION_TYPE_3(NAME, RETURN, ARG1, ARG2, ARG3) NAME,
3343 #define DEF_FUNCTION_TYPE_4(NAME, RETURN, ARG1, ARG2, ARG3, ARG4) NAME,
3344 #define DEF_FUNCTION_TYPE_5(NAME, RETURN, ARG1, ARG2, ARG3, ARG4, ARG5) NAME,
3345 #define DEF_FUNCTION_TYPE_6(NAME, RETURN, ARG1, ARG2, ARG3, ARG4, ARG5, ARG6) NAME,
3346 #define DEF_FUNCTION_TYPE_7(NAME, RETURN, ARG1, ARG2, ARG3, ARG4, ARG5, ARG6, ARG7) NAME,
3347 #define DEF_FUNCTION_TYPE_VAR_0(NAME, RETURN) NAME,
3348 #define DEF_FUNCTION_TYPE_VAR_1(NAME, RETURN, ARG1) NAME,
3349 #define DEF_FUNCTION_TYPE_VAR_2(NAME, RETURN, ARG1, ARG2) NAME,
3350 #define DEF_FUNCTION_TYPE_VAR_3(NAME, RETURN, ARG1, ARG2, ARG3) NAME,
3351 #define DEF_FUNCTION_TYPE_VAR_4(NAME, RETURN, ARG1, ARG2, ARG3, ARG4) NAME,
3352 #define DEF_FUNCTION_TYPE_VAR_5(NAME, RETURN, ARG1, ARG2, ARG3, ARG4, ARG6) \
3353   NAME,
3354 #define DEF_POINTER_TYPE(NAME, TYPE) NAME,
3355 #include "builtin-types.def"
3356 #undef DEF_PRIMITIVE_TYPE
3357 #undef DEF_FUNCTION_TYPE_0
3358 #undef DEF_FUNCTION_TYPE_1
3359 #undef DEF_FUNCTION_TYPE_2
3360 #undef DEF_FUNCTION_TYPE_3
3361 #undef DEF_FUNCTION_TYPE_4
3362 #undef DEF_FUNCTION_TYPE_5
3363 #undef DEF_FUNCTION_TYPE_6
3364 #undef DEF_FUNCTION_TYPE_7
3365 #undef DEF_FUNCTION_TYPE_VAR_0
3366 #undef DEF_FUNCTION_TYPE_VAR_1
3367 #undef DEF_FUNCTION_TYPE_VAR_2
3368 #undef DEF_FUNCTION_TYPE_VAR_3
3369 #undef DEF_FUNCTION_TYPE_VAR_4
3370 #undef DEF_FUNCTION_TYPE_VAR_5
3371 #undef DEF_POINTER_TYPE
3372   BT_LAST
3373 };
3374
3375 typedef enum c_builtin_type builtin_type;
3376
3377 /* A temporary array for c_common_nodes_and_builtins.  Used in
3378    communication with def_fn_type.  */
3379 static tree builtin_types[(int) BT_LAST + 1];
3380
3381 /* A helper function for c_common_nodes_and_builtins.  Build function type
3382    for DEF with return type RET and N arguments.  If VAR is true, then the
3383    function should be variadic after those N arguments.
3384
3385    Takes special care not to ICE if any of the types involved are
3386    error_mark_node, which indicates that said type is not in fact available
3387    (see builtin_type_for_size).  In which case the function type as a whole
3388    should be error_mark_node.  */
3389
3390 static void
3391 def_fn_type (builtin_type def, builtin_type ret, bool var, int n, ...)
3392 {
3393   tree args = NULL, t;
3394   va_list list;
3395   int i;
3396
3397   va_start (list, n);
3398   for (i = 0; i < n; ++i)
3399     {
3400       builtin_type a = va_arg (list, builtin_type);
3401       t = builtin_types[a];
3402       if (t == error_mark_node)
3403         goto egress;
3404       args = tree_cons (NULL_TREE, t, args);
3405     }
3406   va_end (list);
3407
3408   args = nreverse (args);
3409   if (!var)
3410     args = chainon (args, void_list_node);
3411
3412   t = builtin_types[ret];
3413   if (t == error_mark_node)
3414     goto egress;
3415   t = build_function_type (t, args);
3416
3417  egress:
3418   builtin_types[def] = t;
3419 }
3420
3421 /* Build builtin functions common to both C and C++ language
3422    frontends.  */
3423
3424 static void
3425 c_define_builtins (tree va_list_ref_type_node, tree va_list_arg_type_node)
3426 {
3427 #define DEF_PRIMITIVE_TYPE(ENUM, VALUE) \
3428   builtin_types[ENUM] = VALUE;
3429 #define DEF_FUNCTION_TYPE_0(ENUM, RETURN) \
3430   def_fn_type (ENUM, RETURN, 0, 0);
3431 #define DEF_FUNCTION_TYPE_1(ENUM, RETURN, ARG1) \
3432   def_fn_type (ENUM, RETURN, 0, 1, ARG1);
3433 #define DEF_FUNCTION_TYPE_2(ENUM, RETURN, ARG1, ARG2) \
3434   def_fn_type (ENUM, RETURN, 0, 2, ARG1, ARG2);
3435 #define DEF_FUNCTION_TYPE_3(ENUM, RETURN, ARG1, ARG2, ARG3) \
3436   def_fn_type (ENUM, RETURN, 0, 3, ARG1, ARG2, ARG3);
3437 #define DEF_FUNCTION_TYPE_4(ENUM, RETURN, ARG1, ARG2, ARG3, ARG4) \
3438   def_fn_type (ENUM, RETURN, 0, 4, ARG1, ARG2, ARG3, ARG4);
3439 #define DEF_FUNCTION_TYPE_5(ENUM, RETURN, ARG1, ARG2, ARG3, ARG4, ARG5) \
3440   def_fn_type (ENUM, RETURN, 0, 5, ARG1, ARG2, ARG3, ARG4, ARG5);
3441 #define DEF_FUNCTION_TYPE_6(ENUM, RETURN, ARG1, ARG2, ARG3, ARG4, ARG5, \
3442                             ARG6)                                       \
3443   def_fn_type (ENUM, RETURN, 0, 6, ARG1, ARG2, ARG3, ARG4, ARG5, ARG6);
3444 #define DEF_FUNCTION_TYPE_7(ENUM, RETURN, ARG1, ARG2, ARG3, ARG4, ARG5, \
3445                             ARG6, ARG7)                                 \
3446   def_fn_type (ENUM, RETURN, 0, 7, ARG1, ARG2, ARG3, ARG4, ARG5, ARG6, ARG7);
3447 #define DEF_FUNCTION_TYPE_VAR_0(ENUM, RETURN) \
3448   def_fn_type (ENUM, RETURN, 1, 0);
3449 #define DEF_FUNCTION_TYPE_VAR_1(ENUM, RETURN, ARG1) \
3450   def_fn_type (ENUM, RETURN, 1, 1, ARG1);
3451 #define DEF_FUNCTION_TYPE_VAR_2(ENUM, RETURN, ARG1, ARG2) \
3452   def_fn_type (ENUM, RETURN, 1, 2, ARG1, ARG2);
3453 #define DEF_FUNCTION_TYPE_VAR_3(ENUM, RETURN, ARG1, ARG2, ARG3) \
3454   def_fn_type (ENUM, RETURN, 1, 3, ARG1, ARG2, ARG3);
3455 #define DEF_FUNCTION_TYPE_VAR_4(ENUM, RETURN, ARG1, ARG2, ARG3, ARG4) \
3456   def_fn_type (ENUM, RETURN, 1, 4, ARG1, ARG2, ARG3, ARG4);
3457 #define DEF_FUNCTION_TYPE_VAR_5(ENUM, RETURN, ARG1, ARG2, ARG3, ARG4, ARG5) \
3458   def_fn_type (ENUM, RETURN, 1, 5, ARG1, ARG2, ARG3, ARG4, ARG5);
3459 #define DEF_POINTER_TYPE(ENUM, TYPE) \
3460   builtin_types[(int) ENUM] = build_pointer_type (builtin_types[(int) TYPE]);
3461
3462 #include "builtin-types.def"
3463
3464 #undef DEF_PRIMITIVE_TYPE
3465 #undef DEF_FUNCTION_TYPE_1
3466 #undef DEF_FUNCTION_TYPE_2
3467 #undef DEF_FUNCTION_TYPE_3
3468 #undef DEF_FUNCTION_TYPE_4
3469 #undef DEF_FUNCTION_TYPE_5
3470 #undef DEF_FUNCTION_TYPE_6
3471 #undef DEF_FUNCTION_TYPE_VAR_0
3472 #undef DEF_FUNCTION_TYPE_VAR_1
3473 #undef DEF_FUNCTION_TYPE_VAR_2
3474 #undef DEF_FUNCTION_TYPE_VAR_3
3475 #undef DEF_FUNCTION_TYPE_VAR_4
3476 #undef DEF_FUNCTION_TYPE_VAR_5
3477 #undef DEF_POINTER_TYPE
3478   builtin_types[(int) BT_LAST] = NULL_TREE;
3479
3480   c_init_attributes ();
3481
3482 #define DEF_BUILTIN(ENUM, NAME, CLASS, TYPE, LIBTYPE, BOTH_P, FALLBACK_P, \
3483                     NONANSI_P, ATTRS, IMPLICIT, COND)                   \
3484   if (NAME && COND)                                                     \
3485     def_builtin_1 (ENUM, NAME, CLASS,                                   \
3486                    builtin_types[(int) TYPE],                           \
3487                    builtin_types[(int) LIBTYPE],                        \
3488                    BOTH_P, FALLBACK_P, NONANSI_P,                       \
3489                    built_in_attributes[(int) ATTRS], IMPLICIT);
3490 #include "builtins.def"
3491 #undef DEF_BUILTIN
3492
3493   build_common_builtin_nodes ();
3494
3495   targetm.init_builtins ();
3496   if (flag_mudflap)
3497     mudflap_init ();
3498 }
3499
3500 /* Build tree nodes and builtin functions common to both C and C++ language
3501    frontends.  */
3502
3503 void
3504 c_common_nodes_and_builtins (void)
3505 {
3506   int wchar_type_size;
3507   tree array_domain_type;
3508   tree va_list_ref_type_node;
3509   tree va_list_arg_type_node;
3510
3511   /* Define `int' and `char' first so that dbx will output them first.  */
3512   record_builtin_type (RID_INT, NULL, integer_type_node);
3513   record_builtin_type (RID_CHAR, "char", char_type_node);
3514
3515   /* `signed' is the same as `int'.  FIXME: the declarations of "signed",
3516      "unsigned long", "long long unsigned" and "unsigned short" were in C++
3517      but not C.  Are the conditionals here needed?  */
3518   if (c_dialect_cxx ())
3519     record_builtin_type (RID_SIGNED, NULL, integer_type_node);
3520   record_builtin_type (RID_LONG, "long int", long_integer_type_node);
3521   record_builtin_type (RID_UNSIGNED, "unsigned int", unsigned_type_node);
3522   record_builtin_type (RID_MAX, "long unsigned int",
3523                        long_unsigned_type_node);
3524   if (c_dialect_cxx ())
3525     record_builtin_type (RID_MAX, "unsigned long", long_unsigned_type_node);
3526   record_builtin_type (RID_MAX, "long long int",
3527                        long_long_integer_type_node);
3528   record_builtin_type (RID_MAX, "long long unsigned int",
3529                        long_long_unsigned_type_node);
3530   if (c_dialect_cxx ())
3531     record_builtin_type (RID_MAX, "long long unsigned",
3532                          long_long_unsigned_type_node);
3533   record_builtin_type (RID_SHORT, "short int", short_integer_type_node);
3534   record_builtin_type (RID_MAX, "short unsigned int",
3535                        short_unsigned_type_node);
3536   if (c_dialect_cxx ())
3537     record_builtin_type (RID_MAX, "unsigned short",
3538                          short_unsigned_type_node);
3539
3540   /* Define both `signed char' and `unsigned char'.  */
3541   record_builtin_type (RID_MAX, "signed char", signed_char_type_node);
3542   record_builtin_type (RID_MAX, "unsigned char", unsigned_char_type_node);
3543
3544   /* These are types that c_common_type_for_size and
3545      c_common_type_for_mode use.  */
3546   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
3547                                          intQI_type_node));
3548   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
3549                                          intHI_type_node));
3550   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
3551                                          intSI_type_node));
3552   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
3553                                          intDI_type_node));
3554 #if HOST_BITS_PER_WIDE_INT >= 64
3555   if (targetm.scalar_mode_supported_p (TImode))
3556     lang_hooks.decls.pushdecl (build_decl (TYPE_DECL,
3557                                            get_identifier ("__int128_t"),
3558                                            intTI_type_node));
3559 #endif
3560   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
3561                                          unsigned_intQI_type_node));
3562   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
3563                                          unsigned_intHI_type_node));
3564   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
3565                                          unsigned_intSI_type_node));
3566   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
3567                                          unsigned_intDI_type_node));
3568 #if HOST_BITS_PER_WIDE_INT >= 64
3569   if (targetm.scalar_mode_supported_p (TImode))
3570     lang_hooks.decls.pushdecl (build_decl (TYPE_DECL,
3571                                            get_identifier ("__uint128_t"),
3572                                            unsigned_intTI_type_node));
3573 #endif
3574
3575   /* Create the widest literal types.  */
3576   widest_integer_literal_type_node
3577     = make_signed_type (HOST_BITS_PER_WIDE_INT * 2);
3578   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
3579                                          widest_integer_literal_type_node));
3580
3581   widest_unsigned_literal_type_node
3582     = make_unsigned_type (HOST_BITS_PER_WIDE_INT * 2);
3583   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
3584                                          widest_unsigned_literal_type_node));
3585
3586   /* `unsigned long' is the standard type for sizeof.
3587      Note that stddef.h uses `unsigned long',
3588      and this must agree, even if long and int are the same size.  */
3589   size_type_node =
3590     TREE_TYPE (identifier_global_value (get_identifier (SIZE_TYPE)));
3591   signed_size_type_node = c_common_signed_type (size_type_node);
3592   set_sizetype (size_type_node);
3593
3594   pid_type_node =
3595     TREE_TYPE (identifier_global_value (get_identifier (PID_TYPE)));
3596
3597   build_common_tree_nodes_2 (flag_short_double);
3598
3599   record_builtin_type (RID_FLOAT, NULL, float_type_node);
3600   record_builtin_type (RID_DOUBLE, NULL, double_type_node);
3601   record_builtin_type (RID_MAX, "long double", long_double_type_node);
3602
3603   /* Only supported decimal floating point extension if the target
3604      actually supports underlying modes. */
3605   if (targetm.scalar_mode_supported_p (SDmode)
3606       && targetm.scalar_mode_supported_p (DDmode)
3607       && targetm.scalar_mode_supported_p (TDmode))
3608     {
3609       record_builtin_type (RID_DFLOAT32, NULL, dfloat32_type_node);
3610       record_builtin_type (RID_DFLOAT64, NULL, dfloat64_type_node);
3611       record_builtin_type (RID_DFLOAT128, NULL, dfloat128_type_node);
3612     }
3613
3614   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL,
3615                                          get_identifier ("complex int"),
3616                                          complex_integer_type_node));
3617   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL,
3618                                          get_identifier ("complex float"),
3619                                          complex_float_type_node));
3620   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL,
3621                                          get_identifier ("complex double"),
3622                                          complex_double_type_node));
3623   lang_hooks.decls.pushdecl
3624     (build_decl (TYPE_DECL, get_identifier ("complex long double"),
3625                  complex_long_double_type_node));
3626
3627   if (c_dialect_cxx ())
3628     /* For C++, make fileptr_type_node a distinct void * type until
3629        FILE type is defined.  */
3630     fileptr_type_node = build_variant_type_copy (ptr_type_node);
3631
3632   record_builtin_type (RID_VOID, NULL, void_type_node);
3633
3634   /* Set the TYPE_NAME for any variants that were built before
3635      record_builtin_type gave names to the built-in types. */
3636   {
3637     tree void_name = TYPE_NAME (void_type_node);
3638     TYPE_NAME (void_type_node) = NULL_TREE;
3639     TYPE_NAME (build_qualified_type (void_type_node, TYPE_QUAL_CONST))
3640       = void_name;
3641     TYPE_NAME (void_type_node) = void_name;
3642   }
3643
3644   /* This node must not be shared.  */
3645   void_zero_node = make_node (INTEGER_CST);
3646   TREE_TYPE (void_zero_node) = void_type_node;
3647
3648   void_list_node = build_void_list_node ();
3649
3650   /* Make a type to be the domain of a few array types
3651      whose domains don't really matter.
3652      200 is small enough that it always fits in size_t
3653      and large enough that it can hold most function names for the
3654      initializations of __FUNCTION__ and __PRETTY_FUNCTION__.  */
3655   array_domain_type = build_index_type (size_int (200));
3656
3657   /* Make a type for arrays of characters.
3658      With luck nothing will ever really depend on the length of this
3659      array type.  */
3660   char_array_type_node
3661     = build_array_type (char_type_node, array_domain_type);
3662
3663   /* Likewise for arrays of ints.  */
3664   int_array_type_node
3665     = build_array_type (integer_type_node, array_domain_type);
3666
3667   string_type_node = build_pointer_type (char_type_node);
3668   const_string_type_node
3669     = build_pointer_type (build_qualified_type
3670                           (char_type_node, TYPE_QUAL_CONST));
3671
3672   /* This is special for C++ so functions can be overloaded.  */
3673   wchar_type_node = get_identifier (MODIFIED_WCHAR_TYPE);
3674   wchar_type_node = TREE_TYPE (identifier_global_value (wchar_type_node));
3675   wchar_type_size = TYPE_PRECISION (wchar_type_node);
3676   if (c_dialect_cxx ())
3677     {
3678       if (TYPE_UNSIGNED (wchar_type_node))
3679         wchar_type_node = make_unsigned_type (wchar_type_size);
3680       else
3681         wchar_type_node = make_signed_type (wchar_type_size);
3682       record_builtin_type (RID_WCHAR, "wchar_t", wchar_type_node);
3683     }
3684   else
3685     {
3686       signed_wchar_type_node = c_common_signed_type (wchar_type_node);
3687       unsigned_wchar_type_node = unsigned_type_for (wchar_type_node);
3688     }
3689
3690   /* This is for wide string constants.  */
3691   wchar_array_type_node
3692     = build_array_type (wchar_type_node, array_domain_type);
3693
3694   wint_type_node =
3695     TREE_TYPE (identifier_global_value (get_identifier (WINT_TYPE)));
3696
3697   intmax_type_node =
3698     TREE_TYPE (identifier_global_value (get_identifier (INTMAX_TYPE)));
3699   uintmax_type_node =
3700     TREE_TYPE (identifier_global_value (get_identifier (UINTMAX_TYPE)));
3701
3702   default_function_type = build_function_type (integer_type_node, NULL_TREE);
3703   ptrdiff_type_node
3704     = TREE_TYPE (identifier_global_value (get_identifier (PTRDIFF_TYPE)));
3705   unsigned_ptrdiff_type_node = unsigned_type_for (ptrdiff_type_node);
3706
3707   lang_hooks.decls.pushdecl
3708     (build_decl (TYPE_DECL, get_identifier ("__builtin_va_list"),
3709                  va_list_type_node));
3710
3711   if (TREE_CODE (va_list_type_node) == ARRAY_TYPE)
3712     {
3713       va_list_arg_type_node = va_list_ref_type_node =
3714         build_pointer_type (TREE_TYPE (va_list_type_node));
3715     }
3716   else
3717     {
3718       va_list_arg_type_node = va_list_type_node;
3719       va_list_ref_type_node = build_reference_type (va_list_type_node);
3720     }
3721
3722   if (!flag_preprocess_only)
3723     c_define_builtins (va_list_ref_type_node, va_list_arg_type_node);
3724
3725   main_identifier_node = get_identifier ("main");
3726
3727   /* Create the built-in __null node.  It is important that this is
3728      not shared.  */
3729   null_node = make_node (INTEGER_CST);
3730   TREE_TYPE (null_node) = c_common_type_for_size (POINTER_SIZE, 0);
3731
3732   /* Since builtin_types isn't gc'ed, don't export these nodes.  */
3733   memset (builtin_types, 0, sizeof (builtin_types));
3734 }
3735
3736 /* Look up the function in built_in_decls that corresponds to DECL
3737    and set ASMSPEC as its user assembler name.  DECL must be a
3738    function decl that declares a builtin.  */
3739
3740 void
3741 set_builtin_user_assembler_name (tree decl, const char *asmspec)
3742 {
3743   tree builtin;
3744   gcc_assert (TREE_CODE (decl) == FUNCTION_DECL
3745               && DECL_BUILT_IN_CLASS (decl) == BUILT_IN_NORMAL
3746               && asmspec != 0);
3747
3748   builtin = built_in_decls [DECL_FUNCTION_CODE (decl)];
3749   set_user_assembler_name (builtin, asmspec);
3750   if (DECL_FUNCTION_CODE (decl) == BUILT_IN_MEMCPY)
3751     init_block_move_fn (asmspec);
3752   else if (DECL_FUNCTION_CODE (decl) == BUILT_IN_MEMSET)
3753     init_block_clear_fn (asmspec);
3754 }
3755
3756 /* The number of named compound-literals generated thus far.  */
3757 static GTY(()) int compound_literal_number;
3758
3759 /* Set DECL_NAME for DECL, a VAR_DECL for a compound-literal.  */
3760
3761 void
3762 set_compound_literal_name (tree decl)
3763 {
3764   char *name;
3765   ASM_FORMAT_PRIVATE_NAME (name, "__compound_literal",
3766                            compound_literal_number);
3767   compound_literal_number++;
3768   DECL_NAME (decl) = get_identifier (name);
3769 }
3770
3771 tree
3772 build_va_arg (tree expr, tree type)
3773 {
3774   return build1 (VA_ARG_EXPR, type, expr);
3775 }
3776
3777
3778 /* Linked list of disabled built-in functions.  */
3779
3780 typedef struct disabled_builtin
3781 {
3782   const char *name;
3783   struct disabled_builtin *next;
3784 } disabled_builtin;
3785 static disabled_builtin *disabled_builtins = NULL;
3786
3787 static bool builtin_function_disabled_p (const char *);
3788
3789 /* Disable a built-in function specified by -fno-builtin-NAME.  If NAME
3790    begins with "__builtin_", give an error.  */
3791
3792 void
3793 disable_builtin_function (const char *name)
3794 {
3795   if (strncmp (name, "__builtin_", strlen ("__builtin_")) == 0)
3796     error ("cannot disable built-in function %qs", name);
3797   else
3798     {
3799       disabled_builtin *new_disabled_builtin = XNEW (disabled_builtin);
3800       new_disabled_builtin->name = name;
3801       new_disabled_builtin->next = disabled_builtins;
3802       disabled_builtins = new_disabled_builtin;
3803     }
3804 }
3805
3806
3807 /* Return true if the built-in function NAME has been disabled, false
3808    otherwise.  */
3809
3810 static bool
3811 builtin_function_disabled_p (const char *name)
3812 {
3813   disabled_builtin *p;
3814   for (p = disabled_builtins; p != NULL; p = p->next)
3815     {
3816       if (strcmp (name, p->name) == 0)
3817         return true;
3818     }
3819   return false;
3820 }
3821
3822
3823 /* Worker for DEF_BUILTIN.
3824    Possibly define a builtin function with one or two names.
3825    Does not declare a non-__builtin_ function if flag_no_builtin, or if
3826    nonansi_p and flag_no_nonansi_builtin.  */
3827
3828 static void
3829 def_builtin_1 (enum built_in_function fncode,
3830                const char *name,
3831                enum built_in_class fnclass,
3832                tree fntype, tree libtype,
3833                bool both_p, bool fallback_p, bool nonansi_p,
3834                tree fnattrs, bool implicit_p)
3835 {
3836   tree decl;
3837   const char *libname;
3838
3839   if (fntype == error_mark_node)
3840     return;
3841
3842   gcc_assert ((!both_p && !fallback_p)
3843               || !strncmp (name, "__builtin_",
3844                            strlen ("__builtin_")));
3845
3846   libname = name + strlen ("__builtin_");
3847   decl = add_builtin_function (name, fntype, fncode, fnclass,
3848                                (fallback_p ? libname : NULL),
3849                                fnattrs);
3850   if (both_p
3851       && !flag_no_builtin && !builtin_function_disabled_p (libname)
3852       && !(nonansi_p && flag_no_nonansi_builtin))
3853     add_builtin_function (libname, libtype, fncode, fnclass,
3854                           NULL, fnattrs);
3855
3856   built_in_decls[(int) fncode] = decl;
3857   if (implicit_p)
3858     implicit_built_in_decls[(int) fncode] = decl;
3859 }
3860 \f
3861 /* Nonzero if the type T promotes to int.  This is (nearly) the
3862    integral promotions defined in ISO C99 6.3.1.1/2.  */
3863
3864 bool
3865 c_promoting_integer_type_p (tree t)
3866 {
3867   switch (TREE_CODE (t))
3868     {
3869     case INTEGER_TYPE:
3870       return (TYPE_MAIN_VARIANT (t) == char_type_node
3871               || TYPE_MAIN_VARIANT (t) == signed_char_type_node
3872               || TYPE_MAIN_VARIANT (t) == unsigned_char_type_node
3873               || TYPE_MAIN_VARIANT (t) == short_integer_type_node
3874               || TYPE_MAIN_VARIANT (t) == short_unsigned_type_node
3875               || TYPE_PRECISION (t) < TYPE_PRECISION (integer_type_node));
3876
3877     case ENUMERAL_TYPE:
3878       /* ??? Technically all enumerations not larger than an int
3879          promote to an int.  But this is used along code paths
3880          that only want to notice a size change.  */
3881       return TYPE_PRECISION (t) < TYPE_PRECISION (integer_type_node);
3882
3883     case BOOLEAN_TYPE:
3884       return 1;
3885
3886     default:
3887       return 0;
3888     }
3889 }
3890
3891 /* Return 1 if PARMS specifies a fixed number of parameters
3892    and none of their types is affected by default promotions.  */
3893
3894 int
3895 self_promoting_args_p (tree parms)
3896 {
3897   tree t;
3898   for (t = parms; t; t = TREE_CHAIN (t))
3899     {
3900       tree type = TREE_VALUE (t);
3901
3902       if (type == error_mark_node)
3903         continue;
3904
3905       if (TREE_CHAIN (t) == 0 && type != void_type_node)
3906         return 0;
3907
3908       if (type == 0)
3909         return 0;
3910
3911       if (TYPE_MAIN_VARIANT (type) == float_type_node)
3912         return 0;
3913
3914       if (c_promoting_integer_type_p (type))
3915         return 0;
3916     }
3917   return 1;
3918 }
3919
3920 /* Recursively examines the array elements of TYPE, until a non-array
3921    element type is found.  */
3922
3923 tree
3924 strip_array_types (tree type)
3925 {
3926   while (TREE_CODE (type) == ARRAY_TYPE)
3927     type = TREE_TYPE (type);
3928
3929   return type;
3930 }
3931
3932 /* Recursively remove any '*' or '&' operator from TYPE.  */
3933 tree
3934 strip_pointer_operator (tree t)
3935 {
3936   while (POINTER_TYPE_P (t))
3937     t = TREE_TYPE (t);
3938   return t;
3939 }
3940
3941 /* Recursively remove pointer or array type from TYPE. */
3942 tree
3943 strip_pointer_or_array_types (tree t)
3944 {
3945   while (TREE_CODE (t) == ARRAY_TYPE || POINTER_TYPE_P (t))
3946     t = TREE_TYPE (t);
3947   return t;
3948 }
3949
3950 /* Used to compare case labels.  K1 and K2 are actually tree nodes
3951    representing case labels, or NULL_TREE for a `default' label.
3952    Returns -1 if K1 is ordered before K2, -1 if K1 is ordered after
3953    K2, and 0 if K1 and K2 are equal.  */
3954
3955 int
3956 case_compare (splay_tree_key k1, splay_tree_key k2)
3957 {
3958   /* Consider a NULL key (such as arises with a `default' label) to be
3959      smaller than anything else.  */
3960   if (!k1)
3961     return k2 ? -1 : 0;
3962   else if (!k2)
3963     return k1 ? 1 : 0;
3964
3965   return tree_int_cst_compare ((tree) k1, (tree) k2);
3966 }
3967
3968 /* Process a case label for the range LOW_VALUE ... HIGH_VALUE.  If
3969    LOW_VALUE and HIGH_VALUE are both NULL_TREE then this case label is
3970    actually a `default' label.  If only HIGH_VALUE is NULL_TREE, then
3971    case label was declared using the usual C/C++ syntax, rather than
3972    the GNU case range extension.  CASES is a tree containing all the
3973    case ranges processed so far; COND is the condition for the
3974    switch-statement itself.  Returns the CASE_LABEL_EXPR created, or
3975    ERROR_MARK_NODE if no CASE_LABEL_EXPR is created.  */
3976
3977 tree
3978 c_add_case_label (splay_tree cases, tree cond, tree orig_type,
3979                   tree low_value, tree high_value)
3980 {
3981   tree type;
3982   tree label;
3983   tree case_label;
3984   splay_tree_node node;
3985
3986   /* Create the LABEL_DECL itself.  */
3987   label = create_artificial_label ();
3988
3989   /* If there was an error processing the switch condition, bail now
3990      before we get more confused.  */
3991   if (!cond || cond == error_mark_node)
3992     goto error_out;
3993
3994   if ((low_value && TREE_TYPE (low_value)
3995        && POINTER_TYPE_P (TREE_TYPE (low_value)))
3996       || (high_value && TREE_TYPE (high_value)
3997           && POINTER_TYPE_P (TREE_TYPE (high_value))))
3998     {
3999       error ("pointers are not permitted as case values");
4000       goto error_out;
4001     }
4002
4003   /* Case ranges are a GNU extension.  */
4004   if (high_value && pedantic)
4005     pedwarn ("range expressions in switch statements are non-standard");
4006
4007   type = TREE_TYPE (cond);
4008   if (low_value)
4009     {
4010       low_value = check_case_value (low_value);
4011       low_value = convert_and_check (type, low_value);
4012       if (low_value == error_mark_node)
4013         goto error_out;
4014     }
4015   if (high_value)
4016     {
4017       high_value = check_case_value (high_value);
4018       high_value = convert_and_check (type, high_value);
4019       if (high_value == error_mark_node)
4020         goto error_out;
4021     }
4022
4023   if (low_value && high_value)
4024     {
4025       /* If the LOW_VALUE and HIGH_VALUE are the same, then this isn't
4026          really a case range, even though it was written that way.
4027          Remove the HIGH_VALUE to simplify later processing.  */
4028       if (tree_int_cst_equal (low_value, high_value))
4029         high_value = NULL_TREE;
4030       else if (!tree_int_cst_lt (low_value, high_value))
4031         warning (0, "empty range specified");
4032     }
4033
4034   /* See if the case is in range of the type of the original testing
4035      expression.  If both low_value and high_value are out of range,
4036      don't insert the case label and return NULL_TREE.  */
4037   if (low_value
4038       && !check_case_bounds (type, orig_type,
4039                              &low_value, high_value ? &high_value : NULL))
4040     return NULL_TREE;
4041
4042   /* Look up the LOW_VALUE in the table of case labels we already
4043      have.  */
4044   node = splay_tree_lookup (cases, (splay_tree_key) low_value);
4045   /* If there was not an exact match, check for overlapping ranges.
4046      There's no need to do this if there's no LOW_VALUE or HIGH_VALUE;
4047      that's a `default' label and the only overlap is an exact match.  */
4048   if (!node && (low_value || high_value))
4049     {
4050       splay_tree_node low_bound;
4051       splay_tree_node high_bound;
4052
4053       /* Even though there wasn't an exact match, there might be an
4054          overlap between this case range and another case range.
4055          Since we've (inductively) not allowed any overlapping case
4056          ranges, we simply need to find the greatest low case label
4057          that is smaller that LOW_VALUE, and the smallest low case
4058          label that is greater than LOW_VALUE.  If there is an overlap
4059          it will occur in one of these two ranges.  */
4060       low_bound = splay_tree_predecessor (cases,
4061                                           (splay_tree_key) low_value);
4062       high_bound = splay_tree_successor (cases,
4063                                          (splay_tree_key) low_value);
4064
4065       /* Check to see if the LOW_BOUND overlaps.  It is smaller than
4066          the LOW_VALUE, so there is no need to check unless the
4067          LOW_BOUND is in fact itself a case range.  */
4068       if (low_bound
4069           && CASE_HIGH ((tree) low_bound->value)
4070           && tree_int_cst_compare (CASE_HIGH ((tree) low_bound->value),
4071                                     low_value) >= 0)
4072         node = low_bound;
4073       /* Check to see if the HIGH_BOUND overlaps.  The low end of that
4074          range is bigger than the low end of the current range, so we
4075          are only interested if the current range is a real range, and
4076          not an ordinary case label.  */
4077       else if (high_bound
4078                && high_value
4079                && (tree_int_cst_compare ((tree) high_bound->key,
4080                                          high_value)
4081                    <= 0))
4082         node = high_bound;
4083     }
4084   /* If there was an overlap, issue an error.  */
4085   if (node)
4086     {
4087       tree duplicate = CASE_LABEL ((tree) node->value);
4088
4089       if (high_value)
4090         {
4091           error ("duplicate (or overlapping) case value");
4092           error ("%Jthis is the first entry overlapping that value", duplicate);
4093         }
4094       else if (low_value)
4095         {
4096           error ("duplicate case value") ;
4097           error ("%Jpreviously used here", duplicate);
4098         }
4099       else
4100         {
4101           error ("multiple default labels in one switch");
4102           error ("%Jthis is the first default label", duplicate);
4103         }
4104       goto error_out;
4105     }
4106
4107   /* Add a CASE_LABEL to the statement-tree.  */
4108   case_label = add_stmt (build_case_label (low_value, high_value, label));
4109   /* Register this case label in the splay tree.  */
4110   splay_tree_insert (cases,
4111                      (splay_tree_key) low_value,
4112                      (splay_tree_value) case_label);
4113
4114   return case_label;
4115
4116  error_out:
4117   /* Add a label so that the back-end doesn't think that the beginning of
4118      the switch is unreachable.  Note that we do not add a case label, as
4119      that just leads to duplicates and thence to failure later on.  */
4120   if (!cases->root)
4121     {
4122       tree t = create_artificial_label ();
4123       add_stmt (build_stmt (LABEL_EXPR, t));
4124     }
4125   return error_mark_node;
4126 }
4127
4128 /* Subroutines of c_do_switch_warnings, called via splay_tree_foreach.
4129    Used to verify that case values match up with enumerator values.  */
4130
4131 static void
4132 match_case_to_enum_1 (tree key, tree type, tree label)
4133 {
4134   char buf[2 + 2*HOST_BITS_PER_WIDE_INT/4 + 1];
4135
4136   /* ??? Not working too hard to print the double-word value.
4137      Should perhaps be done with %lwd in the diagnostic routines?  */
4138   if (TREE_INT_CST_HIGH (key) == 0)
4139     snprintf (buf, sizeof (buf), HOST_WIDE_INT_PRINT_UNSIGNED,
4140               TREE_INT_CST_LOW (key));
4141   else if (!TYPE_UNSIGNED (type)
4142            && TREE_INT_CST_HIGH (key) == -1
4143            && TREE_INT_CST_LOW (key) != 0)
4144     snprintf (buf, sizeof (buf), "-" HOST_WIDE_INT_PRINT_UNSIGNED,
4145               -TREE_INT_CST_LOW (key));
4146   else
4147     snprintf (buf, sizeof (buf), HOST_WIDE_INT_PRINT_DOUBLE_HEX,
4148               TREE_INT_CST_HIGH (key), TREE_INT_CST_LOW (key));
4149
4150   if (TYPE_NAME (type) == 0)
4151     warning (0, "%Jcase value %qs not in enumerated type",
4152              CASE_LABEL (label), buf);
4153   else
4154     warning (0, "%Jcase value %qs not in enumerated type %qT",
4155              CASE_LABEL (label), buf, type);
4156 }
4157
4158 /* Subroutine of c_do_switch_warnings, called via splay_tree_foreach.
4159    Used to verify that case values match up with enumerator values.  */
4160
4161 static int
4162 match_case_to_enum (splay_tree_node node, void *data)
4163 {
4164   tree label = (tree) node->value;
4165   tree type = (tree) data;
4166
4167   /* Skip default case.  */
4168   if (!CASE_LOW (label))
4169     return 0;
4170
4171   /* If CASE_LOW_SEEN is not set, that means CASE_LOW did not appear
4172      when we did our enum->case scan.  Reset our scratch bit after.  */
4173   if (!CASE_LOW_SEEN (label))
4174     match_case_to_enum_1 (CASE_LOW (label), type, label);
4175   else
4176     CASE_LOW_SEEN (label) = 0;
4177
4178   /* If CASE_HIGH is non-null, we have a range.  If CASE_HIGH_SEEN is
4179      not set, that means that CASE_HIGH did not appear when we did our
4180      enum->case scan.  Reset our scratch bit after.  */
4181   if (CASE_HIGH (label))
4182     {
4183       if (!CASE_HIGH_SEEN (label))
4184         match_case_to_enum_1 (CASE_HIGH (label), type, label);
4185       else
4186         CASE_HIGH_SEEN (label) = 0;
4187     }
4188
4189   return 0;
4190 }
4191
4192 /* Handle -Wswitch*.  Called from the front end after parsing the
4193    switch construct.  */
4194 /* ??? Should probably be somewhere generic, since other languages
4195    besides C and C++ would want this.  At the moment, however, C/C++
4196    are the only tree-ssa languages that support enumerations at all,
4197    so the point is moot.  */
4198
4199 void
4200 c_do_switch_warnings (splay_tree cases, location_t switch_location,
4201                       tree type, tree cond)
4202 {
4203   splay_tree_node default_node;
4204   splay_tree_node node;
4205   tree chain;
4206
4207   if (!warn_switch && !warn_switch_enum && !warn_switch_default)
4208     return;
4209
4210   default_node = splay_tree_lookup (cases, (splay_tree_key) NULL);
4211   if (!default_node)
4212     warning (OPT_Wswitch_default, "%Hswitch missing default case",
4213              &switch_location);
4214
4215   /* From here on, we only care about about enumerated types.  */
4216   if (!type || TREE_CODE (type) != ENUMERAL_TYPE)
4217     return;
4218
4219   /* If the switch expression was an enumerated type, check that
4220      exactly all enumeration literals are covered by the cases.
4221      The check is made when -Wswitch was specified and there is no
4222      default case, or when -Wswitch-enum was specified.  */
4223
4224   if (!warn_switch_enum
4225       && !(warn_switch && !default_node))
4226     return;
4227
4228   /* Clearing COND if it is not an integer constant simplifies
4229      the tests inside the loop below.  */
4230   if (TREE_CODE (cond) != INTEGER_CST)
4231     cond = NULL_TREE;
4232
4233   /* The time complexity here is O(N*lg(N)) worst case, but for the
4234       common case of monotonically increasing enumerators, it is
4235       O(N), since the nature of the splay tree will keep the next
4236       element adjacent to the root at all times.  */
4237
4238   for (chain = TYPE_VALUES (type); chain; chain = TREE_CHAIN (chain))
4239     {
4240       tree value = TREE_VALUE (chain);
4241       node = splay_tree_lookup (cases, (splay_tree_key) value);
4242       if (node)
4243         {
4244           /* Mark the CASE_LOW part of the case entry as seen.  */
4245           tree label = (tree) node->value;
4246           CASE_LOW_SEEN (label) = 1;
4247           continue;
4248         }
4249
4250       /* Even though there wasn't an exact match, there might be a
4251          case range which includes the enumator's value.  */
4252       node = splay_tree_predecessor (cases, (splay_tree_key) value);
4253       if (node && CASE_HIGH ((tree) node->value))
4254         {
4255           tree label = (tree) node->value;
4256           int cmp = tree_int_cst_compare (CASE_HIGH (label), value);
4257           if (cmp >= 0)
4258             {
4259               /* If we match the upper bound exactly, mark the CASE_HIGH
4260                  part of the case entry as seen.  */
4261               if (cmp == 0)
4262                 CASE_HIGH_SEEN (label) = 1;
4263               continue;
4264             }
4265         }
4266
4267       /* We've now determined that this enumerated literal isn't
4268          handled by the case labels of the switch statement.  */
4269
4270       /* If the switch expression is a constant, we only really care
4271          about whether that constant is handled by the switch.  */
4272       if (cond && tree_int_cst_compare (cond, value))
4273         continue;
4274
4275       warning (0, "%Henumeration value %qE not handled in switch",
4276                &switch_location, TREE_PURPOSE (chain));
4277     }
4278
4279   /* Warn if there are case expressions that don't correspond to
4280      enumerators.  This can occur since C and C++ don't enforce
4281      type-checking of assignments to enumeration variables.
4282
4283      The time complexity here is now always O(N) worst case, since
4284      we should have marked both the lower bound and upper bound of
4285      every disjoint case label, with CASE_LOW_SEEN and CASE_HIGH_SEEN
4286      above.  This scan also resets those fields.  */
4287   splay_tree_foreach (cases, match_case_to_enum, type);
4288 }
4289
4290 /* Finish an expression taking the address of LABEL (an
4291    IDENTIFIER_NODE).  Returns an expression for the address.  */
4292
4293 tree
4294 finish_label_address_expr (tree label)
4295 {
4296   tree result;
4297
4298   if (pedantic)
4299     pedwarn ("taking the address of a label is non-standard");
4300
4301   if (label == error_mark_node)
4302     return error_mark_node;
4303
4304   label = lookup_label (label);
4305   if (label == NULL_TREE)
4306     result = null_pointer_node;
4307   else
4308     {
4309       TREE_USED (label) = 1;
4310       result = build1 (ADDR_EXPR, ptr_type_node, label);
4311       /* The current function in not necessarily uninlinable.
4312          Computed gotos are incompatible with inlining, but the value
4313          here could be used only in a diagnostic, for example.  */
4314     }
4315
4316   return result;
4317 }
4318
4319 /* Hook used by expand_expr to expand language-specific tree codes.  */
4320 /* The only things that should go here are bits needed to expand
4321    constant initializers.  Everything else should be handled by the
4322    gimplification routines.  */
4323
4324 rtx
4325 c_expand_expr (tree exp, rtx target, enum machine_mode tmode,
4326                int modifier /* Actually enum_modifier.  */,
4327                rtx *alt_rtl)
4328 {
4329   switch (TREE_CODE (exp))
4330     {
4331     case COMPOUND_LITERAL_EXPR:
4332       {
4333         /* Initialize the anonymous variable declared in the compound
4334            literal, then return the variable.  */
4335         tree decl = COMPOUND_LITERAL_EXPR_DECL (exp);
4336         emit_local_var (decl);
4337         return expand_expr_real (decl, target, tmode, modifier, alt_rtl);
4338       }
4339
4340     default:
4341       gcc_unreachable ();
4342     }
4343 }
4344
4345
4346 /* Generate the RTL for the body of FNDECL.  */
4347
4348 void
4349 c_expand_body (tree fndecl)
4350 {
4351   tree_rest_of_compilation (fndecl);
4352 }
4353
4354 /* Hook used by staticp to handle language-specific tree codes.  */
4355
4356 tree
4357 c_staticp (tree exp)
4358 {
4359   return (TREE_CODE (exp) == COMPOUND_LITERAL_EXPR
4360           && TREE_STATIC (COMPOUND_LITERAL_EXPR_DECL (exp))
4361           ? exp : NULL);
4362 }
4363 \f
4364
4365 /* Given a boolean expression ARG, return a tree representing an increment
4366    or decrement (as indicated by CODE) of ARG.  The front end must check for
4367    invalid cases (e.g., decrement in C++).  */
4368 tree
4369 boolean_increment (enum tree_code code, tree arg)
4370 {
4371   tree val;
4372   tree true_res = boolean_true_node;
4373
4374   arg = stabilize_reference (arg);
4375   switch (code)
4376     {
4377     case PREINCREMENT_EXPR:
4378       val = build2 (MODIFY_EXPR, TREE_TYPE (arg), arg, true_res);
4379       break;
4380     case POSTINCREMENT_EXPR:
4381       val = build2 (MODIFY_EXPR, TREE_TYPE (arg), arg, true_res);
4382       arg = save_expr (arg);
4383       val = build2 (COMPOUND_EXPR, TREE_TYPE (arg), val, arg);
4384       val = build2 (COMPOUND_EXPR, TREE_TYPE (arg), arg, val);
4385       break;
4386     case PREDECREMENT_EXPR:
4387       val = build2 (MODIFY_EXPR, TREE_TYPE (arg), arg,
4388                     invert_truthvalue (arg));
4389       break;
4390     case POSTDECREMENT_EXPR:
4391       val = build2 (MODIFY_EXPR, TREE_TYPE (arg), arg,
4392                     invert_truthvalue (arg));
4393       arg = save_expr (arg);
4394       val = build2 (COMPOUND_EXPR, TREE_TYPE (arg), val, arg);
4395       val = build2 (COMPOUND_EXPR, TREE_TYPE (arg), arg, val);
4396       break;
4397     default:
4398       gcc_unreachable ();
4399     }
4400   TREE_SIDE_EFFECTS (val) = 1;
4401   return val;
4402 }
4403 \f
4404 /* Built-in macros for stddef.h, that require macros defined in this
4405    file.  */
4406 void
4407 c_stddef_cpp_builtins(void)
4408 {
4409   builtin_define_with_value ("__SIZE_TYPE__", SIZE_TYPE, 0);
4410   builtin_define_with_value ("__PTRDIFF_TYPE__", PTRDIFF_TYPE, 0);
4411   builtin_define_with_value ("__WCHAR_TYPE__", MODIFIED_WCHAR_TYPE, 0);
4412   builtin_define_with_value ("__WINT_TYPE__", WINT_TYPE, 0);
4413   builtin_define_with_value ("__INTMAX_TYPE__", INTMAX_TYPE, 0);
4414   builtin_define_with_value ("__UINTMAX_TYPE__", UINTMAX_TYPE, 0);
4415 }
4416
4417 static void
4418 c_init_attributes (void)
4419 {
4420   /* Fill in the built_in_attributes array.  */
4421 #define DEF_ATTR_NULL_TREE(ENUM)                                \
4422   built_in_attributes[(int) ENUM] = NULL_TREE;
4423 #define DEF_ATTR_INT(ENUM, VALUE)                               \
4424   built_in_attributes[(int) ENUM] = build_int_cst (NULL_TREE, VALUE);
4425 #define DEF_ATTR_IDENT(ENUM, STRING)                            \
4426   built_in_attributes[(int) ENUM] = get_identifier (STRING);
4427 #define DEF_ATTR_TREE_LIST(ENUM, PURPOSE, VALUE, CHAIN) \
4428   built_in_attributes[(int) ENUM]                       \
4429     = tree_cons (built_in_attributes[(int) PURPOSE],    \
4430                  built_in_attributes[(int) VALUE],      \
4431                  built_in_attributes[(int) CHAIN]);
4432 #include "builtin-attrs.def"
4433 #undef DEF_ATTR_NULL_TREE
4434 #undef DEF_ATTR_INT
4435 #undef DEF_ATTR_IDENT
4436 #undef DEF_ATTR_TREE_LIST
4437 }
4438
4439 /* Attribute handlers common to C front ends.  */
4440
4441 /* Handle a "packed" attribute; arguments as in
4442    struct attribute_spec.handler.  */
4443
4444 static tree
4445 handle_packed_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4446                          int flags, bool *no_add_attrs)
4447 {
4448   if (TYPE_P (*node))
4449     {
4450       if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
4451         *node = build_variant_type_copy (*node);
4452       TYPE_PACKED (*node) = 1;
4453     }
4454   else if (TREE_CODE (*node) == FIELD_DECL)
4455     {
4456       if (TYPE_ALIGN (TREE_TYPE (*node)) <= BITS_PER_UNIT)
4457         warning (OPT_Wattributes,
4458                  "%qE attribute ignored for field of type %qT",
4459                  name, TREE_TYPE (*node));
4460       else
4461         DECL_PACKED (*node) = 1;
4462     }
4463   /* We can't set DECL_PACKED for a VAR_DECL, because the bit is
4464      used for DECL_REGISTER.  It wouldn't mean anything anyway.
4465      We can't set DECL_PACKED on the type of a TYPE_DECL, because
4466      that changes what the typedef is typing.  */
4467   else
4468     {
4469       warning (OPT_Wattributes, "%qE attribute ignored", name);
4470       *no_add_attrs = true;
4471     }
4472
4473   return NULL_TREE;
4474 }
4475
4476 /* Handle a "nocommon" attribute; arguments as in
4477    struct attribute_spec.handler.  */
4478
4479 static tree
4480 handle_nocommon_attribute (tree *node, tree name,
4481                            tree ARG_UNUSED (args),
4482                            int ARG_UNUSED (flags), bool *no_add_attrs)
4483 {
4484   if (TREE_CODE (*node) == VAR_DECL)
4485     DECL_COMMON (*node) = 0;
4486   else
4487     {
4488       warning (OPT_Wattributes, "%qE attribute ignored", name);
4489       *no_add_attrs = true;
4490     }
4491
4492   return NULL_TREE;
4493 }
4494
4495 /* Handle a "common" attribute; arguments as in
4496    struct attribute_spec.handler.  */
4497
4498 static tree
4499 handle_common_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4500                          int ARG_UNUSED (flags), bool *no_add_attrs)
4501 {
4502   if (TREE_CODE (*node) == VAR_DECL)
4503     DECL_COMMON (*node) = 1;
4504   else
4505     {
4506       warning (OPT_Wattributes, "%qE attribute ignored", name);
4507       *no_add_attrs = true;
4508     }
4509
4510   return NULL_TREE;
4511 }
4512
4513 /* Handle a "noreturn" attribute; arguments as in
4514    struct attribute_spec.handler.  */
4515
4516 static tree
4517 handle_noreturn_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4518                            int ARG_UNUSED (flags), bool *no_add_attrs)
4519 {
4520   tree type = TREE_TYPE (*node);
4521
4522   /* See FIXME comment in c_common_attribute_table.  */
4523   if (TREE_CODE (*node) == FUNCTION_DECL)
4524     TREE_THIS_VOLATILE (*node) = 1;
4525   else if (TREE_CODE (type) == POINTER_TYPE
4526            && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE)
4527     TREE_TYPE (*node)
4528       = build_pointer_type
4529         (build_type_variant (TREE_TYPE (type),
4530                              TYPE_READONLY (TREE_TYPE (type)), 1));
4531   else
4532     {
4533       warning (OPT_Wattributes, "%qE attribute ignored", name);
4534       *no_add_attrs = true;
4535     }
4536
4537   return NULL_TREE;
4538 }
4539
4540 /* Handle a "hot" and attribute; arguments as in
4541    struct attribute_spec.handler.  */
4542
4543 static tree
4544 handle_hot_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4545                           int ARG_UNUSED (flags), bool *no_add_attrs)
4546 {
4547   if (TREE_CODE (*node) == FUNCTION_DECL)
4548     {
4549       if (lookup_attribute ("cold", DECL_ATTRIBUTES (*node)) != NULL)
4550         {
4551           warning (OPT_Wattributes, "%qE attribute conflicts with attribute %s",
4552                    name, "cold");
4553           *no_add_attrs = true;
4554         }
4555       /* Do nothing else, just set the attribute.  We'll get at
4556          it later with lookup_attribute.  */
4557     }
4558   else
4559     {
4560       warning (OPT_Wattributes, "%qE attribute ignored", name);
4561       *no_add_attrs = true;
4562     }
4563
4564   return NULL_TREE;
4565 }
4566 /* Handle a "cold" and attribute; arguments as in
4567    struct attribute_spec.handler.  */
4568
4569 static tree
4570 handle_cold_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4571                        int ARG_UNUSED (flags), bool *no_add_attrs)
4572 {
4573   if (TREE_CODE (*node) == FUNCTION_DECL)
4574     {
4575       if (lookup_attribute ("hot", DECL_ATTRIBUTES (*node)) != NULL)
4576         {
4577           warning (OPT_Wattributes, "%qE attribute conflicts with attribute %s",
4578                    name, "hot");
4579           *no_add_attrs = true;
4580         }
4581       /* Do nothing else, just set the attribute.  We'll get at
4582          it later with lookup_attribute.  */
4583     }
4584   else
4585     {
4586       warning (OPT_Wattributes, "%qE attribute ignored", name);
4587       *no_add_attrs = true;
4588     }
4589
4590   return NULL_TREE;
4591 }
4592
4593 /* Handle a "noinline" attribute; arguments as in
4594    struct attribute_spec.handler.  */
4595
4596 static tree
4597 handle_noinline_attribute (tree *node, tree name,
4598                            tree ARG_UNUSED (args),
4599                            int ARG_UNUSED (flags), bool *no_add_attrs)
4600 {
4601   if (TREE_CODE (*node) == FUNCTION_DECL)
4602     DECL_UNINLINABLE (*node) = 1;
4603   else
4604     {
4605       warning (OPT_Wattributes, "%qE attribute ignored", name);
4606       *no_add_attrs = true;
4607     }
4608
4609   return NULL_TREE;
4610 }
4611
4612 /* Handle a "always_inline" attribute; arguments as in
4613    struct attribute_spec.handler.  */
4614
4615 static tree
4616 handle_always_inline_attribute (tree *node, tree name,
4617                                 tree ARG_UNUSED (args),
4618                                 int ARG_UNUSED (flags),
4619                                 bool *no_add_attrs)
4620 {
4621   if (TREE_CODE (*node) == FUNCTION_DECL)
4622     {
4623       /* Do nothing else, just set the attribute.  We'll get at
4624          it later with lookup_attribute.  */
4625     }
4626   else
4627     {
4628       warning (OPT_Wattributes, "%qE attribute ignored", name);
4629       *no_add_attrs = true;
4630     }
4631
4632   return NULL_TREE;
4633 }
4634
4635 /* Handle a "gnu_inline" attribute; arguments as in
4636    struct attribute_spec.handler.  */
4637
4638 static tree
4639 handle_gnu_inline_attribute (tree *node, tree name,
4640                              tree ARG_UNUSED (args),
4641                              int ARG_UNUSED (flags),
4642                              bool *no_add_attrs)
4643 {
4644   if (TREE_CODE (*node) == FUNCTION_DECL && DECL_DECLARED_INLINE_P (*node))
4645     {
4646       /* Do nothing else, just set the attribute.  We'll get at
4647          it later with lookup_attribute.  */
4648     }
4649   else
4650     {
4651       warning (OPT_Wattributes, "%qE attribute ignored", name);
4652       *no_add_attrs = true;
4653     }
4654
4655   return NULL_TREE;
4656 }
4657
4658 /* Handle a "flatten" attribute; arguments as in
4659    struct attribute_spec.handler.  */
4660
4661 static tree
4662 handle_flatten_attribute (tree *node, tree name,
4663                           tree args ATTRIBUTE_UNUSED,
4664                           int flags ATTRIBUTE_UNUSED, bool *no_add_attrs)
4665 {
4666   if (TREE_CODE (*node) == FUNCTION_DECL)
4667     /* Do nothing else, just set the attribute.  We'll get at
4668        it later with lookup_attribute.  */
4669     ;
4670   else
4671     {
4672       warning (OPT_Wattributes, "%qE attribute ignored", name);
4673       *no_add_attrs = true;
4674     }
4675
4676   return NULL_TREE;
4677 }
4678
4679
4680 /* Handle a "used" attribute; arguments as in
4681    struct attribute_spec.handler.  */
4682
4683 static tree
4684 handle_used_attribute (tree *pnode, tree name, tree ARG_UNUSED (args),
4685                        int ARG_UNUSED (flags), bool *no_add_attrs)
4686 {
4687   tree node = *pnode;
4688
4689   if (TREE_CODE (node) == FUNCTION_DECL
4690       || (TREE_CODE (node) == VAR_DECL && TREE_STATIC (node)))
4691     {
4692       TREE_USED (node) = 1;
4693       DECL_PRESERVE_P (node) = 1;
4694     }
4695   else
4696     {
4697       warning (OPT_Wattributes, "%qE attribute ignored", name);
4698       *no_add_attrs = true;
4699     }
4700
4701   return NULL_TREE;
4702 }
4703
4704 /* Handle a "unused" attribute; arguments as in
4705    struct attribute_spec.handler.  */
4706
4707 static tree
4708 handle_unused_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4709                          int flags, bool *no_add_attrs)
4710 {
4711   if (DECL_P (*node))
4712     {
4713       tree decl = *node;
4714
4715       if (TREE_CODE (decl) == PARM_DECL
4716           || TREE_CODE (decl) == VAR_DECL
4717           || TREE_CODE (decl) == FUNCTION_DECL
4718           || TREE_CODE (decl) == LABEL_DECL
4719           || TREE_CODE (decl) == TYPE_DECL)
4720         TREE_USED (decl) = 1;
4721       else
4722         {
4723           warning (OPT_Wattributes, "%qE attribute ignored", name);
4724           *no_add_attrs = true;
4725         }
4726     }
4727   else
4728     {
4729       if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
4730         *node = build_variant_type_copy (*node);
4731       TREE_USED (*node) = 1;
4732     }
4733
4734   return NULL_TREE;
4735 }
4736
4737 /* Handle a "externally_visible" attribute; arguments as in
4738    struct attribute_spec.handler.  */
4739
4740 static tree
4741 handle_externally_visible_attribute (tree *pnode, tree name,
4742                                      tree ARG_UNUSED (args),
4743                                      int ARG_UNUSED (flags),
4744                                      bool *no_add_attrs)
4745 {
4746   tree node = *pnode;
4747
4748   if (TREE_CODE (node) == FUNCTION_DECL || TREE_CODE (node) == VAR_DECL)
4749     {
4750       if ((!TREE_STATIC (node) && TREE_CODE (node) != FUNCTION_DECL
4751            && !DECL_EXTERNAL (node)) || !TREE_PUBLIC (node))
4752         {
4753           warning (OPT_Wattributes,
4754                    "%qE attribute have effect only on public objects", name);
4755           *no_add_attrs = true;
4756         }
4757     }
4758   else
4759     {
4760       warning (OPT_Wattributes, "%qE attribute ignored", name);
4761       *no_add_attrs = true;
4762     }
4763
4764   return NULL_TREE;
4765 }
4766
4767 /* Handle a "const" attribute; arguments as in
4768    struct attribute_spec.handler.  */
4769
4770 static tree
4771 handle_const_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4772                         int ARG_UNUSED (flags), bool *no_add_attrs)
4773 {
4774   tree type = TREE_TYPE (*node);
4775
4776   /* See FIXME comment on noreturn in c_common_attribute_table.  */
4777   if (TREE_CODE (*node) == FUNCTION_DECL)
4778     TREE_READONLY (*node) = 1;
4779   else if (TREE_CODE (type) == POINTER_TYPE
4780            && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE)
4781     TREE_TYPE (*node)
4782       = build_pointer_type
4783         (build_type_variant (TREE_TYPE (type), 1,
4784                              TREE_THIS_VOLATILE (TREE_TYPE (type))));
4785   else
4786     {
4787       warning (OPT_Wattributes, "%qE attribute ignored", name);
4788       *no_add_attrs = true;
4789     }
4790
4791   return NULL_TREE;
4792 }
4793
4794 /* Handle a "transparent_union" attribute; arguments as in
4795    struct attribute_spec.handler.  */
4796
4797 static tree
4798 handle_transparent_union_attribute (tree *node, tree name,
4799                                     tree ARG_UNUSED (args), int flags,
4800                                     bool *no_add_attrs)
4801 {
4802   tree type = NULL;
4803
4804   *no_add_attrs = true;
4805
4806   if (DECL_P (*node))
4807     {
4808       if (TREE_CODE (*node) != TYPE_DECL)
4809         goto ignored;
4810       node = &TREE_TYPE (*node);
4811       type = *node;
4812     }
4813   else if (TYPE_P (*node))
4814     type = *node;
4815   else
4816     goto ignored;
4817
4818   if (TREE_CODE (type) == UNION_TYPE)
4819     {
4820       /* When IN_PLACE is set, leave the check for FIELDS and MODE to
4821          the code in finish_struct.  */
4822       if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
4823         {
4824           if (TYPE_FIELDS (type) == NULL_TREE
4825               || TYPE_MODE (type) != DECL_MODE (TYPE_FIELDS (type)))
4826             goto ignored;
4827
4828           /* A type variant isn't good enough, since we don't a cast
4829              to such a type removed as a no-op.  */
4830           *node = type = build_duplicate_type (type);
4831         }
4832
4833       TYPE_TRANSPARENT_UNION (type) = 1;
4834       return NULL_TREE;
4835     }
4836
4837  ignored:
4838   warning (OPT_Wattributes, "%qE attribute ignored", name);
4839   return NULL_TREE;
4840 }
4841
4842 /* Subroutine of handle_{con,de}structor_attribute.  Evaluate ARGS to
4843    get the requested priority for a constructor or destructor,
4844    possibly issuing diagnostics for invalid or reserved
4845    priorities.  */
4846
4847 static priority_type
4848 get_priority (tree args, bool is_destructor)
4849 {
4850   HOST_WIDE_INT pri;
4851   tree arg;
4852
4853   if (!args)
4854     return DEFAULT_INIT_PRIORITY;
4855
4856   if (!SUPPORTS_INIT_PRIORITY)
4857     {
4858       if (is_destructor)
4859         error ("destructor priorities are not supported");
4860       else
4861         error ("constructor priorities are not supported");
4862       return DEFAULT_INIT_PRIORITY;
4863     }
4864
4865   arg = TREE_VALUE (args);
4866   if (!host_integerp (arg, /*pos=*/0)
4867       || !INTEGRAL_TYPE_P (TREE_TYPE (arg)))
4868     goto invalid;
4869
4870   pri = tree_low_cst (TREE_VALUE (args), /*pos=*/0);
4871   if (pri < 0 || pri > MAX_INIT_PRIORITY)
4872     goto invalid;
4873
4874   if (pri <= MAX_RESERVED_INIT_PRIORITY)
4875     {
4876       if (is_destructor)
4877         warning (0,
4878                  "destructor priorities from 0 to %d are reserved "
4879                  "for the implementation",
4880                  MAX_RESERVED_INIT_PRIORITY);
4881       else
4882         warning (0,
4883                  "constructor priorities from 0 to %d are reserved "
4884                  "for the implementation",
4885                  MAX_RESERVED_INIT_PRIORITY);
4886     }
4887   return pri;
4888
4889  invalid:
4890   if (is_destructor)
4891     error ("destructor priorities must be integers from 0 to %d inclusive",
4892            MAX_INIT_PRIORITY);
4893   else
4894     error ("constructor priorities must be integers from 0 to %d inclusive",
4895            MAX_INIT_PRIORITY);
4896   return DEFAULT_INIT_PRIORITY;
4897 }
4898
4899 /* Handle a "constructor" attribute; arguments as in
4900    struct attribute_spec.handler.  */
4901
4902 static tree
4903 handle_constructor_attribute (tree *node, tree name, tree args,
4904                               int ARG_UNUSED (flags),
4905                               bool *no_add_attrs)
4906 {
4907   tree decl = *node;
4908   tree type = TREE_TYPE (decl);
4909
4910   if (TREE_CODE (decl) == FUNCTION_DECL
4911       && TREE_CODE (type) == FUNCTION_TYPE
4912       && decl_function_context (decl) == 0)
4913     {
4914       priority_type priority;
4915       DECL_STATIC_CONSTRUCTOR (decl) = 1;
4916       priority = get_priority (args, /*is_destructor=*/false);
4917       SET_DECL_INIT_PRIORITY (decl, priority);
4918       TREE_USED (decl) = 1;
4919     }
4920   else
4921     {
4922       warning (OPT_Wattributes, "%qE attribute ignored", name);
4923       *no_add_attrs = true;
4924     }
4925
4926   return NULL_TREE;
4927 }
4928
4929 /* Handle a "destructor" attribute; arguments as in
4930    struct attribute_spec.handler.  */
4931
4932 static tree
4933 handle_destructor_attribute (tree *node, tree name, tree args,
4934                              int ARG_UNUSED (flags),
4935                              bool *no_add_attrs)
4936 {
4937   tree decl = *node;
4938   tree type = TREE_TYPE (decl);
4939
4940   if (TREE_CODE (decl) == FUNCTION_DECL
4941       && TREE_CODE (type) == FUNCTION_TYPE
4942       && decl_function_context (decl) == 0)
4943     {
4944       priority_type priority;
4945       DECL_STATIC_DESTRUCTOR (decl) = 1;
4946       priority = get_priority (args, /*is_destructor=*/true);
4947       SET_DECL_FINI_PRIORITY (decl, priority);
4948       TREE_USED (decl) = 1;
4949     }
4950   else
4951     {
4952       warning (OPT_Wattributes, "%qE attribute ignored", name);
4953       *no_add_attrs = true;
4954     }
4955
4956   return NULL_TREE;
4957 }
4958
4959 /* Handle a "mode" attribute; arguments as in
4960    struct attribute_spec.handler.  */
4961
4962 static tree
4963 handle_mode_attribute (tree *node, tree name, tree args,
4964                        int ARG_UNUSED (flags), bool *no_add_attrs)
4965 {
4966   tree type = *node;
4967
4968   *no_add_attrs = true;
4969
4970   if (TREE_CODE (TREE_VALUE (args)) != IDENTIFIER_NODE)
4971     warning (OPT_Wattributes, "%qE attribute ignored", name);
4972   else
4973     {
4974       int j;
4975       const char *p = IDENTIFIER_POINTER (TREE_VALUE (args));
4976       int len = strlen (p);
4977       enum machine_mode mode = VOIDmode;
4978       tree typefm;
4979       bool valid_mode;
4980
4981       if (len > 4 && p[0] == '_' && p[1] == '_'
4982           && p[len - 1] == '_' && p[len - 2] == '_')
4983         {
4984           char *newp = (char *) alloca (len - 1);
4985
4986           strcpy (newp, &p[2]);
4987           newp[len - 4] = '\0';
4988           p = newp;
4989         }
4990
4991       /* Change this type to have a type with the specified mode.
4992          First check for the special modes.  */
4993       if (!strcmp (p, "byte"))
4994         mode = byte_mode;
4995       else if (!strcmp (p, "word"))
4996         mode = word_mode;
4997       else if (!strcmp (p, "pointer"))
4998         mode = ptr_mode;
4999       else
5000         for (j = 0; j < NUM_MACHINE_MODES; j++)
5001           if (!strcmp (p, GET_MODE_NAME (j)))
5002             {
5003               mode = (enum machine_mode) j;
5004               break;
5005             }
5006
5007       if (mode == VOIDmode)
5008         {
5009           error ("unknown machine mode %qs", p);
5010           return NULL_TREE;
5011         }
5012
5013       valid_mode = false;
5014       switch (GET_MODE_CLASS (mode))
5015         {
5016         case MODE_INT:
5017         case MODE_PARTIAL_INT:
5018         case MODE_FLOAT:
5019         case MODE_DECIMAL_FLOAT:
5020           valid_mode = targetm.scalar_mode_supported_p (mode);
5021           break;
5022
5023         case MODE_COMPLEX_INT:
5024         case MODE_COMPLEX_FLOAT:
5025           valid_mode = targetm.scalar_mode_supported_p (GET_MODE_INNER (mode));
5026           break;
5027
5028         case MODE_VECTOR_INT:
5029         case MODE_VECTOR_FLOAT:
5030           warning (OPT_Wattributes, "specifying vector types with "
5031                    "__attribute__ ((mode)) is deprecated");
5032           warning (OPT_Wattributes,
5033                    "use __attribute__ ((vector_size)) instead");
5034           valid_mode = vector_mode_valid_p (mode);
5035           break;
5036
5037         default:
5038           break;
5039         }
5040       if (!valid_mode)
5041         {
5042           error ("unable to emulate %qs", p);
5043           return NULL_TREE;
5044         }
5045
5046       if (POINTER_TYPE_P (type))
5047         {
5048           tree (*fn)(tree, enum machine_mode, bool);
5049
5050           if (!targetm.valid_pointer_mode (mode))
5051             {
5052               error ("invalid pointer mode %qs", p);
5053               return NULL_TREE;
5054             }
5055
5056           if (TREE_CODE (type) == POINTER_TYPE)
5057             fn = build_pointer_type_for_mode;
5058           else
5059             fn = build_reference_type_for_mode;
5060           typefm = fn (TREE_TYPE (type), mode, false);
5061         }
5062       else
5063         typefm = lang_hooks.types.type_for_mode (mode, TYPE_UNSIGNED (type));
5064
5065       if (typefm == NULL_TREE)
5066         {
5067           error ("no data type for mode %qs", p);
5068           return NULL_TREE;
5069         }
5070       else if (TREE_CODE (type) == ENUMERAL_TYPE)
5071         {
5072           /* For enumeral types, copy the precision from the integer
5073              type returned above.  If not an INTEGER_TYPE, we can't use
5074              this mode for this type.  */
5075           if (TREE_CODE (typefm) != INTEGER_TYPE)
5076             {
5077               error ("cannot use mode %qs for enumeral types", p);
5078               return NULL_TREE;
5079             }
5080
5081           if (flags & ATTR_FLAG_TYPE_IN_PLACE)
5082             {
5083               TYPE_PRECISION (type) = TYPE_PRECISION (typefm);
5084               typefm = type;
5085             }
5086           else
5087             {
5088               /* We cannot build a type variant, as there's code that assumes
5089                  that TYPE_MAIN_VARIANT has the same mode.  This includes the
5090                  debug generators.  Instead, create a subrange type.  This
5091                  results in all of the enumeral values being emitted only once
5092                  in the original, and the subtype gets them by reference.  */
5093               if (TYPE_UNSIGNED (type))
5094                 typefm = make_unsigned_type (TYPE_PRECISION (typefm));
5095               else
5096                 typefm = make_signed_type (TYPE_PRECISION (typefm));
5097               TREE_TYPE (typefm) = type;
5098             }
5099         }
5100       else if (VECTOR_MODE_P (mode)
5101                ? TREE_CODE (type) != TREE_CODE (TREE_TYPE (typefm))
5102                : TREE_CODE (type) != TREE_CODE (typefm))
5103         {
5104           error ("mode %qs applied to inappropriate type", p);
5105           return NULL_TREE;
5106         }
5107
5108       *node = typefm;
5109     }
5110
5111   return NULL_TREE;
5112 }
5113
5114 /* Handle a "section" attribute; arguments as in
5115    struct attribute_spec.handler.  */
5116
5117 static tree
5118 handle_section_attribute (tree *node, tree ARG_UNUSED (name), tree args,
5119                           int ARG_UNUSED (flags), bool *no_add_attrs)
5120 {
5121   tree decl = *node;
5122
5123   if (targetm.have_named_sections)
5124     {
5125       user_defined_section_attribute = true;
5126
5127       if ((TREE_CODE (decl) == FUNCTION_DECL
5128            || TREE_CODE (decl) == VAR_DECL)
5129           && TREE_CODE (TREE_VALUE (args)) == STRING_CST)
5130         {
5131           if (TREE_CODE (decl) == VAR_DECL
5132               && current_function_decl != NULL_TREE
5133               && !TREE_STATIC (decl))
5134             {
5135               error ("%Jsection attribute cannot be specified for "
5136                      "local variables", decl);
5137               *no_add_attrs = true;
5138             }
5139
5140           /* The decl may have already been given a section attribute
5141              from a previous declaration.  Ensure they match.  */
5142           else if (DECL_SECTION_NAME (decl) != NULL_TREE
5143                    && strcmp (TREE_STRING_POINTER (DECL_SECTION_NAME (decl)),
5144                               TREE_STRING_POINTER (TREE_VALUE (args))) != 0)
5145             {
5146               error ("section of %q+D conflicts with previous declaration",
5147                      *node);
5148               *no_add_attrs = true;
5149             }
5150           else
5151             DECL_SECTION_NAME (decl) = TREE_VALUE (args);
5152         }
5153       else
5154         {
5155           error ("section attribute not allowed for %q+D", *node);
5156           *no_add_attrs = true;
5157         }
5158     }
5159   else
5160     {
5161       error ("%Jsection attributes are not supported for this target", *node);
5162       *no_add_attrs = true;
5163     }
5164
5165   return NULL_TREE;
5166 }
5167
5168 /* Handle a "aligned" attribute; arguments as in
5169    struct attribute_spec.handler.  */
5170
5171 static tree
5172 handle_aligned_attribute (tree *node, tree ARG_UNUSED (name), tree args,
5173                           int flags, bool *no_add_attrs)
5174 {
5175   tree decl = NULL_TREE;
5176   tree *type = NULL;
5177   int is_type = 0;
5178   tree align_expr = (args ? TREE_VALUE (args)
5179                      : size_int (BIGGEST_ALIGNMENT / BITS_PER_UNIT));
5180   int i;
5181
5182   if (DECL_P (*node))
5183     {
5184       decl = *node;
5185       type = &TREE_TYPE (decl);
5186       is_type = TREE_CODE (*node) == TYPE_DECL;
5187     }
5188   else if (TYPE_P (*node))
5189     type = node, is_type = 1;
5190
5191   if (TREE_CODE (align_expr) != INTEGER_CST)
5192     {
5193       error ("requested alignment is not a constant");
5194       *no_add_attrs = true;
5195     }
5196   else if ((i = tree_log2 (align_expr)) == -1)
5197     {
5198       error ("requested alignment is not a power of 2");
5199       *no_add_attrs = true;
5200     }
5201   else if (i > HOST_BITS_PER_INT - 2)
5202     {
5203       error ("requested alignment is too large");
5204       *no_add_attrs = true;
5205     }
5206   else if (is_type)
5207     {
5208       /* If we have a TYPE_DECL, then copy the type, so that we
5209          don't accidentally modify a builtin type.  See pushdecl.  */
5210       if (decl && TREE_TYPE (decl) != error_mark_node
5211           && DECL_ORIGINAL_TYPE (decl) == NULL_TREE)
5212         {
5213           tree tt = TREE_TYPE (decl);
5214           *type = build_variant_type_copy (*type);
5215           DECL_ORIGINAL_TYPE (decl) = tt;
5216           TYPE_NAME (*type) = decl;
5217           TREE_USED (*type) = TREE_USED (decl);
5218           TREE_TYPE (decl) = *type;
5219         }
5220       else if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
5221         *type = build_variant_type_copy (*type);
5222
5223       TYPE_ALIGN (*type) = (1 << i) * BITS_PER_UNIT;
5224       TYPE_USER_ALIGN (*type) = 1;
5225     }
5226   else if (TREE_CODE (decl) != VAR_DECL
5227            && TREE_CODE (decl) != FIELD_DECL)
5228     {
5229       error ("alignment may not be specified for %q+D", decl);
5230       *no_add_attrs = true;
5231     }
5232   else
5233     {
5234       DECL_ALIGN (decl) = (1 << i) * BITS_PER_UNIT;
5235       DECL_USER_ALIGN (decl) = 1;
5236     }
5237
5238   return NULL_TREE;
5239 }
5240
5241 /* Handle a "weak" attribute; arguments as in
5242    struct attribute_spec.handler.  */
5243
5244 static tree
5245 handle_weak_attribute (tree *node, tree name,
5246                        tree ARG_UNUSED (args),
5247                        int ARG_UNUSED (flags),
5248                        bool * ARG_UNUSED (no_add_attrs))
5249 {
5250   if (TREE_CODE (*node) == FUNCTION_DECL
5251       || TREE_CODE (*node) == VAR_DECL)
5252     declare_weak (*node);
5253   else
5254     warning (OPT_Wattributes, "%qE attribute ignored", name);
5255
5256
5257   return NULL_TREE;
5258 }
5259
5260 /* Handle an "alias" attribute; arguments as in
5261    struct attribute_spec.handler.  */
5262
5263 static tree
5264 handle_alias_attribute (tree *node, tree name, tree args,
5265                         int ARG_UNUSED (flags), bool *no_add_attrs)
5266 {
5267   tree decl = *node;
5268
5269   if ((TREE_CODE (decl) == FUNCTION_DECL && DECL_INITIAL (decl))
5270       || (TREE_CODE (decl) != FUNCTION_DECL
5271           && TREE_PUBLIC (decl) && !DECL_EXTERNAL (decl))
5272       /* A static variable declaration is always a tentative definition,
5273          but the alias is a non-tentative definition which overrides.  */
5274       || (TREE_CODE (decl) != FUNCTION_DECL
5275           && ! TREE_PUBLIC (decl) && DECL_INITIAL (decl)))
5276     {
5277       error ("%q+D defined both normally and as an alias", decl);
5278       *no_add_attrs = true;
5279     }
5280
5281   /* Note that the very first time we process a nested declaration,
5282      decl_function_context will not be set.  Indeed, *would* never
5283      be set except for the DECL_INITIAL/DECL_EXTERNAL frobbery that
5284      we do below.  After such frobbery, pushdecl would set the context.
5285      In any case, this is never what we want.  */
5286   else if (decl_function_context (decl) == 0 && current_function_decl == NULL)
5287     {
5288       tree id;
5289
5290       id = TREE_VALUE (args);
5291       if (TREE_CODE (id) != STRING_CST)
5292         {
5293           error ("alias argument not a string");
5294           *no_add_attrs = true;
5295           return NULL_TREE;
5296         }
5297       id = get_identifier (TREE_STRING_POINTER (id));
5298       /* This counts as a use of the object pointed to.  */
5299       TREE_USED (id) = 1;
5300
5301       if (TREE_CODE (decl) == FUNCTION_DECL)
5302         DECL_INITIAL (decl) = error_mark_node;
5303       else
5304         {
5305           if (lookup_attribute ("weakref", DECL_ATTRIBUTES (decl)))
5306             DECL_EXTERNAL (decl) = 1;
5307           else
5308             DECL_EXTERNAL (decl) = 0;
5309           TREE_STATIC (decl) = 1;
5310         }
5311     }
5312   else
5313     {
5314       warning (OPT_Wattributes, "%qE attribute ignored", name);
5315       *no_add_attrs = true;
5316     }
5317
5318   return NULL_TREE;
5319 }
5320
5321 /* Handle a "weakref" attribute; arguments as in struct
5322    attribute_spec.handler.  */
5323
5324 static tree
5325 handle_weakref_attribute (tree *node, tree ARG_UNUSED (name), tree args,
5326                           int flags, bool *no_add_attrs)
5327 {
5328   tree attr = NULL_TREE;
5329
5330   /* We must ignore the attribute when it is associated with
5331      local-scoped decls, since attribute alias is ignored and many
5332      such symbols do not even have a DECL_WEAK field.  */
5333   if (decl_function_context (*node) || current_function_decl)
5334     {
5335       warning (OPT_Wattributes, "%qE attribute ignored", name);
5336       *no_add_attrs = true;
5337       return NULL_TREE;
5338     }
5339
5340   /* The idea here is that `weakref("name")' mutates into `weakref,
5341      alias("name")', and weakref without arguments, in turn,
5342      implicitly adds weak. */
5343
5344   if (args)
5345     {
5346       attr = tree_cons (get_identifier ("alias"), args, attr);
5347       attr = tree_cons (get_identifier ("weakref"), NULL_TREE, attr);
5348
5349       *no_add_attrs = true;
5350
5351       decl_attributes (node, attr, flags);
5352     }
5353   else
5354     {
5355       if (lookup_attribute ("alias", DECL_ATTRIBUTES (*node)))
5356         error ("%Jweakref attribute must appear before alias attribute",
5357                *node);
5358
5359       /* Can't call declare_weak because it wants this to be TREE_PUBLIC,
5360          and that isn't supported; and because it wants to add it to
5361          the list of weak decls, which isn't helpful.  */
5362       DECL_WEAK (*node) = 1;
5363     }
5364
5365   return NULL_TREE;
5366 }
5367
5368 /* Handle an "visibility" attribute; arguments as in
5369    struct attribute_spec.handler.  */
5370
5371 static tree
5372 handle_visibility_attribute (tree *node, tree name, tree args,
5373                              int ARG_UNUSED (flags),
5374                              bool *ARG_UNUSED (no_add_attrs))
5375 {
5376   tree decl = *node;
5377   tree id = TREE_VALUE (args);
5378   enum symbol_visibility vis;
5379
5380   if (TYPE_P (*node))
5381     {
5382       if (TREE_CODE (*node) == ENUMERAL_TYPE)
5383         /* OK */;
5384       else if (TREE_CODE (*node) != RECORD_TYPE && TREE_CODE (*node) != UNION_TYPE)
5385         {
5386           warning (OPT_Wattributes, "%qE attribute ignored on non-class types",
5387                    name);
5388           return NULL_TREE;
5389         }
5390       else if (TYPE_FIELDS (*node))
5391         {
5392           error ("%qE attribute ignored because %qT is already defined",
5393                  name, *node);
5394           return NULL_TREE;
5395         }
5396     }
5397   else if (decl_function_context (decl) != 0 || !TREE_PUBLIC (decl))
5398     {
5399       warning (OPT_Wattributes, "%qE attribute ignored", name);
5400       return NULL_TREE;
5401     }
5402
5403   if (TREE_CODE (id) != STRING_CST)
5404     {
5405       error ("visibility argument not a string");
5406       return NULL_TREE;
5407     }
5408
5409   /*  If this is a type, set the visibility on the type decl.  */
5410   if (TYPE_P (decl))
5411     {
5412       decl = TYPE_NAME (decl);
5413       if (!decl)
5414         return NULL_TREE;
5415       if (TREE_CODE (decl) == IDENTIFIER_NODE)
5416         {
5417            warning (OPT_Wattributes, "%qE attribute ignored on types",
5418                     name);
5419            return NULL_TREE;
5420         }
5421     }
5422
5423   if (strcmp (TREE_STRING_POINTER (id), "default") == 0)
5424     vis = VISIBILITY_DEFAULT;
5425   else if (strcmp (TREE_STRING_POINTER (id), "internal") == 0)
5426     vis = VISIBILITY_INTERNAL;
5427   else if (strcmp (TREE_STRING_POINTER (id), "hidden") == 0)
5428     vis = VISIBILITY_HIDDEN;
5429   else if (strcmp (TREE_STRING_POINTER (id), "protected") == 0)
5430     vis = VISIBILITY_PROTECTED;
5431   else
5432     {
5433       error ("visibility argument must be one of \"default\", \"hidden\", \"protected\" or \"internal\"");
5434       vis = VISIBILITY_DEFAULT;
5435     }
5436
5437   if (DECL_VISIBILITY_SPECIFIED (decl)
5438       && vis != DECL_VISIBILITY (decl)
5439       && lookup_attribute ("visibility", (TYPE_P (*node)
5440                                           ? TYPE_ATTRIBUTES (*node)
5441                                           : DECL_ATTRIBUTES (decl))))
5442     error ("%qD redeclared with different visibility", decl);
5443
5444   DECL_VISIBILITY (decl) = vis;
5445   DECL_VISIBILITY_SPECIFIED (decl) = 1;
5446
5447   /* Go ahead and attach the attribute to the node as well.  This is needed
5448      so we can determine whether we have VISIBILITY_DEFAULT because the
5449      visibility was not specified, or because it was explicitly overridden
5450      from the containing scope.  */
5451
5452   return NULL_TREE;
5453 }
5454
5455 /* Determine the ELF symbol visibility for DECL, which is either a
5456    variable or a function.  It is an error to use this function if a
5457    definition of DECL is not available in this translation unit.
5458    Returns true if the final visibility has been determined by this
5459    function; false if the caller is free to make additional
5460    modifications.  */
5461
5462 bool
5463 c_determine_visibility (tree decl)
5464 {
5465   gcc_assert (TREE_CODE (decl) == VAR_DECL
5466               || TREE_CODE (decl) == FUNCTION_DECL);
5467
5468   /* If the user explicitly specified the visibility with an
5469      attribute, honor that.  DECL_VISIBILITY will have been set during
5470      the processing of the attribute.  We check for an explicit
5471      attribute, rather than just checking DECL_VISIBILITY_SPECIFIED,
5472      to distinguish the use of an attribute from the use of a "#pragma
5473      GCC visibility push(...)"; in the latter case we still want other
5474      considerations to be able to overrule the #pragma.  */
5475   if (lookup_attribute ("visibility", DECL_ATTRIBUTES (decl)))
5476     return true;
5477
5478   /* Anything that is exported must have default visibility.  */
5479   if (TARGET_DLLIMPORT_DECL_ATTRIBUTES
5480       && lookup_attribute ("dllexport", DECL_ATTRIBUTES (decl)))
5481     {
5482       DECL_VISIBILITY (decl) = VISIBILITY_DEFAULT;
5483       DECL_VISIBILITY_SPECIFIED (decl) = 1;
5484       return true;
5485     }
5486
5487   /* Set default visibility to whatever the user supplied with
5488      visibility_specified depending on #pragma GCC visibility.  */
5489   if (!DECL_VISIBILITY_SPECIFIED (decl))
5490     {
5491       DECL_VISIBILITY (decl) = default_visibility;
5492       DECL_VISIBILITY_SPECIFIED (decl) = visibility_options.inpragma;
5493     }
5494   return false;
5495 }
5496
5497 /* Handle an "tls_model" attribute; arguments as in
5498    struct attribute_spec.handler.  */
5499
5500 static tree
5501 handle_tls_model_attribute (tree *node, tree name, tree args,
5502                             int ARG_UNUSED (flags), bool *no_add_attrs)
5503 {
5504   tree id;
5505   tree decl = *node;
5506   enum tls_model kind;
5507
5508   *no_add_attrs = true;
5509
5510   if (!DECL_THREAD_LOCAL_P (decl))
5511     {
5512       warning (OPT_Wattributes, "%qE attribute ignored", name);
5513       return NULL_TREE;
5514     }
5515
5516   kind = DECL_TLS_MODEL (decl);
5517   id = TREE_VALUE (args);
5518   if (TREE_CODE (id) != STRING_CST)
5519     {
5520       error ("tls_model argument not a string");
5521       return NULL_TREE;
5522     }
5523
5524   if (!strcmp (TREE_STRING_POINTER (id), "local-exec"))
5525     kind = TLS_MODEL_LOCAL_EXEC;
5526   else if (!strcmp (TREE_STRING_POINTER (id), "initial-exec"))
5527     kind = TLS_MODEL_INITIAL_EXEC;
5528   else if (!strcmp (TREE_STRING_POINTER (id), "local-dynamic"))
5529     kind = optimize ? TLS_MODEL_LOCAL_DYNAMIC : TLS_MODEL_GLOBAL_DYNAMIC;
5530   else if (!strcmp (TREE_STRING_POINTER (id), "global-dynamic"))
5531     kind = TLS_MODEL_GLOBAL_DYNAMIC;
5532   else
5533     error ("tls_model argument must be one of \"local-exec\", \"initial-exec\", \"local-dynamic\" or \"global-dynamic\"");
5534
5535   DECL_TLS_MODEL (decl) = kind;
5536   return NULL_TREE;
5537 }
5538
5539 /* Handle a "no_instrument_function" attribute; arguments as in
5540    struct attribute_spec.handler.  */
5541
5542 static tree
5543 handle_no_instrument_function_attribute (tree *node, tree name,
5544                                          tree ARG_UNUSED (args),
5545                                          int ARG_UNUSED (flags),
5546                                          bool *no_add_attrs)
5547 {
5548   tree decl = *node;
5549
5550   if (TREE_CODE (decl) != FUNCTION_DECL)
5551     {
5552       error ("%J%qE attribute applies only to functions", decl, name);
5553       *no_add_attrs = true;
5554     }
5555   else if (DECL_INITIAL (decl))
5556     {
5557       error ("%Jcan%'t set %qE attribute after definition", decl, name);
5558       *no_add_attrs = true;
5559     }
5560   else
5561     DECL_NO_INSTRUMENT_FUNCTION_ENTRY_EXIT (decl) = 1;
5562
5563   return NULL_TREE;
5564 }
5565
5566 /* Handle a "malloc" attribute; arguments as in
5567    struct attribute_spec.handler.  */
5568
5569 static tree
5570 handle_malloc_attribute (tree *node, tree name, tree ARG_UNUSED (args),
5571                          int ARG_UNUSED (flags), bool *no_add_attrs)
5572 {
5573   if (TREE_CODE (*node) == FUNCTION_DECL
5574       && POINTER_TYPE_P (TREE_TYPE (TREE_TYPE (*node))))
5575     DECL_IS_MALLOC (*node) = 1;
5576   else
5577     {
5578       warning (OPT_Wattributes, "%qE attribute ignored", name);
5579       *no_add_attrs = true;
5580     }
5581
5582   return NULL_TREE;
5583 }
5584
5585 /* Handle a "alloc_size" attribute; arguments as in
5586    struct attribute_spec.handler.  */
5587
5588 static tree
5589 handle_alloc_size_attribute (tree *node, tree ARG_UNUSED (name), tree args,
5590                              int ARG_UNUSED (flags), bool *no_add_attrs)
5591 {
5592   tree params = TYPE_ARG_TYPES (*node);
5593   unsigned arg_count = 0;
5594
5595   for (; TREE_CHAIN (params); params = TREE_CHAIN (params))
5596     arg_count ++;
5597
5598   for (; args; args = TREE_CHAIN (args))
5599     {
5600       tree position = TREE_VALUE (args);
5601
5602       if (TREE_CODE (position) != INTEGER_CST
5603           || TREE_INT_CST_HIGH (position)
5604           || TREE_INT_CST_LOW (position) < 1
5605           || TREE_INT_CST_LOW (position) > arg_count )
5606         {
5607           warning (OPT_Wattributes,
5608                    "alloc_size parameter outside range");
5609           *no_add_attrs = true;
5610           return NULL_TREE;
5611         }
5612     }
5613   return NULL_TREE;
5614 }
5615
5616 /* Handle a "returns_twice" attribute; arguments as in
5617    struct attribute_spec.handler.  */
5618
5619 static tree
5620 handle_returns_twice_attribute (tree *node, tree name, tree ARG_UNUSED (args),
5621                          int ARG_UNUSED (flags), bool *no_add_attrs)
5622 {
5623   if (TREE_CODE (*node) == FUNCTION_DECL)
5624     DECL_IS_RETURNS_TWICE (*node) = 1;
5625   else
5626     {
5627       warning (OPT_Wattributes, "%qE attribute ignored", name);
5628       *no_add_attrs = true;
5629     }
5630
5631   return NULL_TREE;
5632 }
5633
5634 /* Handle a "no_limit_stack" attribute; arguments as in
5635    struct attribute_spec.handler.  */
5636
5637 static tree
5638 handle_no_limit_stack_attribute (tree *node, tree name,
5639                                  tree ARG_UNUSED (args),
5640                                  int ARG_UNUSED (flags),
5641                                  bool *no_add_attrs)
5642 {
5643   tree decl = *node;
5644
5645   if (TREE_CODE (decl) != FUNCTION_DECL)
5646     {
5647       error ("%J%qE attribute applies only to functions", decl, name);
5648       *no_add_attrs = true;
5649     }
5650   else if (DECL_INITIAL (decl))
5651     {
5652       error ("%Jcan%'t set %qE attribute after definition", decl, name);
5653       *no_add_attrs = true;
5654     }
5655   else
5656     DECL_NO_LIMIT_STACK (decl) = 1;
5657
5658   return NULL_TREE;
5659 }
5660
5661 /* Handle a "pure" attribute; arguments as in
5662    struct attribute_spec.handler.  */
5663
5664 static tree
5665 handle_pure_attribute (tree *node, tree name, tree ARG_UNUSED (args),
5666                        int ARG_UNUSED (flags), bool *no_add_attrs)
5667 {
5668   if (TREE_CODE (*node) == FUNCTION_DECL)
5669     DECL_IS_PURE (*node) = 1;
5670   /* ??? TODO: Support types.  */
5671   else
5672     {
5673       warning (OPT_Wattributes, "%qE attribute ignored", name);
5674       *no_add_attrs = true;
5675     }
5676
5677   return NULL_TREE;
5678 }
5679
5680 /* Handle a "no vops" attribute; arguments as in
5681    struct attribute_spec.handler.  */
5682
5683 static tree
5684 handle_novops_attribute (tree *node, tree ARG_UNUSED (name),
5685                          tree ARG_UNUSED (args), int ARG_UNUSED (flags),
5686                          bool *ARG_UNUSED (no_add_attrs))
5687 {
5688   gcc_assert (TREE_CODE (*node) == FUNCTION_DECL);
5689   DECL_IS_NOVOPS (*node) = 1;
5690   return NULL_TREE;
5691 }
5692
5693 /* Handle a "deprecated" attribute; arguments as in
5694    struct attribute_spec.handler.  */
5695
5696 static tree
5697 handle_deprecated_attribute (tree *node, tree name,
5698                              tree ARG_UNUSED (args), int flags,
5699                              bool *no_add_attrs)
5700 {
5701   tree type = NULL_TREE;
5702   int warn = 0;
5703   tree what = NULL_TREE;
5704
5705   if (DECL_P (*node))
5706     {
5707       tree decl = *node;
5708       type = TREE_TYPE (decl);
5709
5710       if (TREE_CODE (decl) == TYPE_DECL
5711           || TREE_CODE (decl) == PARM_DECL
5712           || TREE_CODE (decl) == VAR_DECL
5713           || TREE_CODE (decl) == FUNCTION_DECL
5714           || TREE_CODE (decl) == FIELD_DECL)
5715         TREE_DEPRECATED (decl) = 1;
5716       else
5717         warn = 1;
5718     }
5719   else if (TYPE_P (*node))
5720     {
5721       if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
5722         *node = build_variant_type_copy (*node);
5723       TREE_DEPRECATED (*node) = 1;
5724       type = *node;
5725     }
5726   else
5727     warn = 1;
5728
5729   if (warn)
5730     {
5731       *no_add_attrs = true;
5732       if (type && TYPE_NAME (type))
5733         {
5734           if (TREE_CODE (TYPE_NAME (type)) == IDENTIFIER_NODE)
5735             what = TYPE_NAME (*node);
5736           else if (TREE_CODE (TYPE_NAME (type)) == TYPE_DECL
5737                    && DECL_NAME (TYPE_NAME (type)))
5738             what = DECL_NAME (TYPE_NAME (type));
5739         }
5740       if (what)
5741         warning (OPT_Wattributes, "%qE attribute ignored for %qE", name, what);
5742       else
5743         warning (OPT_Wattributes, "%qE attribute ignored", name);
5744     }
5745
5746   return NULL_TREE;
5747 }
5748
5749 /* Handle a "vector_size" attribute; arguments as in
5750    struct attribute_spec.handler.  */
5751
5752 static tree
5753 handle_vector_size_attribute (tree *node, tree name, tree args,
5754                               int ARG_UNUSED (flags),
5755                               bool *no_add_attrs)
5756 {
5757   unsigned HOST_WIDE_INT vecsize, nunits;
5758   enum machine_mode orig_mode;
5759   tree type = *node, new_type, size;
5760
5761   *no_add_attrs = true;
5762
5763   size = TREE_VALUE (args);
5764
5765   if (!host_integerp (size, 1))
5766     {
5767       warning (OPT_Wattributes, "%qE attribute ignored", name);
5768       return NULL_TREE;
5769     }
5770
5771   /* Get the vector size (in bytes).  */
5772   vecsize = tree_low_cst (size, 1);
5773
5774   /* We need to provide for vector pointers, vector arrays, and
5775      functions returning vectors.  For example:
5776
5777        __attribute__((vector_size(16))) short *foo;
5778
5779      In this case, the mode is SI, but the type being modified is
5780      HI, so we need to look further.  */
5781
5782   while (POINTER_TYPE_P (type)
5783          || TREE_CODE (type) == FUNCTION_TYPE
5784          || TREE_CODE (type) == METHOD_TYPE
5785          || TREE_CODE (type) == ARRAY_TYPE)
5786     type = TREE_TYPE (type);
5787
5788   /* Get the mode of the type being modified.  */
5789   orig_mode = TYPE_MODE (type);
5790
5791   if (TREE_CODE (type) == RECORD_TYPE
5792       || TREE_CODE (type) == UNION_TYPE
5793       || TREE_CODE (type) == VECTOR_TYPE
5794       || (!SCALAR_FLOAT_MODE_P (orig_mode)
5795           && GET_MODE_CLASS (orig_mode) != MODE_INT)
5796       || !host_integerp (TYPE_SIZE_UNIT (type), 1))
5797     {
5798       error ("invalid vector type for attribute %qE", name);
5799       return NULL_TREE;
5800     }
5801
5802   if (vecsize % tree_low_cst (TYPE_SIZE_UNIT (type), 1))
5803     {
5804       error ("vector size not an integral multiple of component size");
5805       return NULL;
5806     }
5807
5808   if (vecsize == 0)
5809     {
5810       error ("zero vector size");
5811       return NULL;
5812     }
5813
5814   /* Calculate how many units fit in the vector.  */
5815   nunits = vecsize / tree_low_cst (TYPE_SIZE_UNIT (type), 1);
5816   if (nunits & (nunits - 1))
5817     {
5818       error ("number of components of the vector not a power of two");
5819       return NULL_TREE;
5820     }
5821
5822   new_type = build_vector_type (type, nunits);
5823
5824   /* Build back pointers if needed.  */
5825   *node = reconstruct_complex_type (*node, new_type);
5826
5827   return NULL_TREE;
5828 }
5829
5830 /* Handle the "nonnull" attribute.  */
5831 static tree
5832 handle_nonnull_attribute (tree *node, tree ARG_UNUSED (name),
5833                           tree args, int ARG_UNUSED (flags),
5834                           bool *no_add_attrs)
5835 {
5836   tree type = *node;
5837   unsigned HOST_WIDE_INT attr_arg_num;
5838
5839   /* If no arguments are specified, all pointer arguments should be
5840      non-null.  Verify a full prototype is given so that the arguments
5841      will have the correct types when we actually check them later.  */
5842   if (!args)
5843     {
5844       if (!TYPE_ARG_TYPES (type))
5845         {
5846           error ("nonnull attribute without arguments on a non-prototype");
5847           *no_add_attrs = true;
5848         }
5849       return NULL_TREE;
5850     }
5851
5852   /* Argument list specified.  Verify that each argument number references
5853      a pointer argument.  */
5854   for (attr_arg_num = 1; args; args = TREE_CHAIN (args))
5855     {
5856       tree argument;
5857       unsigned HOST_WIDE_INT arg_num = 0, ck_num;
5858
5859       if (!get_nonnull_operand (TREE_VALUE (args), &arg_num))
5860         {
5861           error ("nonnull argument has invalid operand number (argument %lu)",
5862                  (unsigned long) attr_arg_num);
5863           *no_add_attrs = true;
5864           return NULL_TREE;
5865         }
5866
5867       argument = TYPE_ARG_TYPES (type);
5868       if (argument)
5869         {
5870           for (ck_num = 1; ; ck_num++)
5871             {
5872               if (!argument || ck_num == arg_num)
5873                 break;
5874               argument = TREE_CHAIN (argument);
5875             }
5876
5877           if (!argument
5878               || TREE_CODE (TREE_VALUE (argument)) == VOID_TYPE)
5879             {
5880               error ("nonnull argument with out-of-range operand number (argument %lu, operand %lu)",
5881                      (unsigned long) attr_arg_num, (unsigned long) arg_num);
5882               *no_add_attrs = true;
5883               return NULL_TREE;
5884             }
5885
5886           if (TREE_CODE (TREE_VALUE (argument)) != POINTER_TYPE)
5887             {
5888               error ("nonnull argument references non-pointer operand (argument %lu, operand %lu)",
5889                    (unsigned long) attr_arg_num, (unsigned long) arg_num);
5890               *no_add_attrs = true;
5891               return NULL_TREE;
5892             }
5893         }
5894     }
5895
5896   return NULL_TREE;
5897 }
5898
5899 /* Check the argument list of a function call for null in argument slots
5900    that are marked as requiring a non-null pointer argument.  The NARGS
5901    arguments are passed in the array ARGARRAY.
5902 */
5903
5904 static void
5905 check_function_nonnull (tree attrs, int nargs, tree *argarray)
5906 {
5907   tree a, args;
5908   int i;
5909
5910   for (a = attrs; a; a = TREE_CHAIN (a))
5911     {
5912       if (is_attribute_p ("nonnull", TREE_PURPOSE (a)))
5913         {
5914           args = TREE_VALUE (a);
5915
5916           /* Walk the argument list.  If we encounter an argument number we
5917              should check for non-null, do it.  If the attribute has no args,
5918              then every pointer argument is checked (in which case the check
5919              for pointer type is done in check_nonnull_arg).  */
5920           for (i = 0; i < nargs; i++)
5921             {
5922               if (!args || nonnull_check_p (args, i + 1))
5923                 check_function_arguments_recurse (check_nonnull_arg, NULL,
5924                                                   argarray[i],
5925                                                   i + 1);
5926             }
5927         }
5928     }
5929 }
5930
5931 /* Check that the Nth argument of a function call (counting backwards
5932    from the end) is a (pointer)0.  The NARGS arguments are passed in the
5933    array ARGARRAY.  */
5934
5935 static void
5936 check_function_sentinel (tree attrs, int nargs, tree *argarray, tree typelist)
5937 {
5938   tree attr = lookup_attribute ("sentinel", attrs);
5939
5940   if (attr)
5941     {
5942       int len = 0;
5943       int pos = 0;
5944       tree sentinel;
5945
5946       /* Skip over the named arguments.  */
5947       while (typelist && len < nargs)
5948         {
5949           typelist = TREE_CHAIN (typelist);
5950           len++;
5951         }
5952
5953       if (TREE_VALUE (attr))
5954         {
5955           tree p = TREE_VALUE (TREE_VALUE (attr));
5956           pos = TREE_INT_CST_LOW (p);
5957         }
5958
5959       /* The sentinel must be one of the varargs, i.e.
5960          in position >= the number of fixed arguments.  */
5961       if ((nargs - 1 - pos) < len)
5962         {
5963           warning (OPT_Wformat,
5964                    "not enough variable arguments to fit a sentinel");
5965           return;
5966         }
5967
5968       /* Validate the sentinel.  */
5969       sentinel = argarray[nargs - 1 - pos];
5970       if ((!POINTER_TYPE_P (TREE_TYPE (sentinel))
5971            || !integer_zerop (sentinel))
5972           /* Although __null (in C++) is only an integer we allow it
5973              nevertheless, as we are guaranteed that it's exactly
5974              as wide as a pointer, and we don't want to force
5975              users to cast the NULL they have written there.
5976              We warn with -Wstrict-null-sentinel, though.  */
5977           && (warn_strict_null_sentinel || null_node != sentinel))
5978         warning (OPT_Wformat, "missing sentinel in function call");
5979     }
5980 }
5981
5982 /* Helper for check_function_nonnull; given a list of operands which
5983    must be non-null in ARGS, determine if operand PARAM_NUM should be
5984    checked.  */
5985
5986 static bool
5987 nonnull_check_p (tree args, unsigned HOST_WIDE_INT param_num)
5988 {
5989   unsigned HOST_WIDE_INT arg_num = 0;
5990
5991   for (; args; args = TREE_CHAIN (args))
5992     {
5993       bool found = get_nonnull_operand (TREE_VALUE (args), &arg_num);
5994
5995       gcc_assert (found);
5996
5997       if (arg_num == param_num)
5998         return true;
5999     }
6000   return false;
6001 }
6002
6003 /* Check that the function argument PARAM (which is operand number
6004    PARAM_NUM) is non-null.  This is called by check_function_nonnull
6005    via check_function_arguments_recurse.  */
6006
6007 static void
6008 check_nonnull_arg (void * ARG_UNUSED (ctx), tree param,
6009                    unsigned HOST_WIDE_INT param_num)
6010 {
6011   /* Just skip checking the argument if it's not a pointer.  This can
6012      happen if the "nonnull" attribute was given without an operand
6013      list (which means to check every pointer argument).  */
6014
6015   if (TREE_CODE (TREE_TYPE (param)) != POINTER_TYPE)
6016     return;
6017
6018   if (integer_zerop (param))
6019     warning (OPT_Wnonnull, "null argument where non-null required "
6020              "(argument %lu)", (unsigned long) param_num);
6021 }
6022
6023 /* Helper for nonnull attribute handling; fetch the operand number
6024    from the attribute argument list.  */
6025
6026 static bool
6027 get_nonnull_operand (tree arg_num_expr, unsigned HOST_WIDE_INT *valp)
6028 {
6029   /* Verify the arg number is a constant.  */
6030   if (TREE_CODE (arg_num_expr) != INTEGER_CST
6031       || TREE_INT_CST_HIGH (arg_num_expr) != 0)
6032     return false;
6033
6034   *valp = TREE_INT_CST_LOW (arg_num_expr);
6035   return true;
6036 }
6037
6038 /* Handle a "nothrow" attribute; arguments as in
6039    struct attribute_spec.handler.  */
6040
6041 static tree
6042 handle_nothrow_attribute (tree *node, tree name, tree ARG_UNUSED (args),
6043                           int ARG_UNUSED (flags), bool *no_add_attrs)
6044 {
6045   if (TREE_CODE (*node) == FUNCTION_DECL)
6046     TREE_NOTHROW (*node) = 1;
6047   /* ??? TODO: Support types.  */
6048   else
6049     {
6050       warning (OPT_Wattributes, "%qE attribute ignored", name);
6051       *no_add_attrs = true;
6052     }
6053
6054   return NULL_TREE;
6055 }
6056
6057 /* Handle a "cleanup" attribute; arguments as in
6058    struct attribute_spec.handler.  */
6059
6060 static tree
6061 handle_cleanup_attribute (tree *node, tree name, tree args,
6062                           int ARG_UNUSED (flags), bool *no_add_attrs)
6063 {
6064   tree decl = *node;
6065   tree cleanup_id, cleanup_decl;
6066
6067   /* ??? Could perhaps support cleanups on TREE_STATIC, much like we do
6068      for global destructors in C++.  This requires infrastructure that
6069      we don't have generically at the moment.  It's also not a feature
6070      we'd be missing too much, since we do have attribute constructor.  */
6071   if (TREE_CODE (decl) != VAR_DECL || TREE_STATIC (decl))
6072     {
6073       warning (OPT_Wattributes, "%qE attribute ignored", name);
6074       *no_add_attrs = true;
6075       return NULL_TREE;
6076     }
6077
6078   /* Verify that the argument is a function in scope.  */
6079   /* ??? We could support pointers to functions here as well, if
6080      that was considered desirable.  */
6081   cleanup_id = TREE_VALUE (args);
6082   if (TREE_CODE (cleanup_id) != IDENTIFIER_NODE)
6083     {
6084       error ("cleanup argument not an identifier");
6085       *no_add_attrs = true;
6086       return NULL_TREE;
6087     }
6088   cleanup_decl = lookup_name (cleanup_id);
6089   if (!cleanup_decl || TREE_CODE (cleanup_decl) != FUNCTION_DECL)
6090     {
6091       error ("cleanup argument not a function");
6092       *no_add_attrs = true;
6093       return NULL_TREE;
6094     }
6095
6096   /* That the function has proper type is checked with the
6097      eventual call to build_function_call.  */
6098
6099   return NULL_TREE;
6100 }
6101
6102 /* Handle a "warn_unused_result" attribute.  No special handling.  */
6103
6104 static tree
6105 handle_warn_unused_result_attribute (tree *node, tree name,
6106                                tree ARG_UNUSED (args),
6107                                int ARG_UNUSED (flags), bool *no_add_attrs)
6108 {
6109   /* Ignore the attribute for functions not returning any value.  */
6110   if (VOID_TYPE_P (TREE_TYPE (*node)))
6111     {
6112       warning (OPT_Wattributes, "%qE attribute ignored", name);
6113       *no_add_attrs = true;
6114     }
6115
6116   return NULL_TREE;
6117 }
6118
6119 /* Handle a "sentinel" attribute.  */
6120
6121 static tree
6122 handle_sentinel_attribute (tree *node, tree name, tree args,
6123                            int ARG_UNUSED (flags), bool *no_add_attrs)
6124 {
6125   tree params = TYPE_ARG_TYPES (*node);
6126
6127   if (!params)
6128     {
6129       warning (OPT_Wattributes,
6130                "%qE attribute requires prototypes with named arguments", name);
6131       *no_add_attrs = true;
6132     }
6133   else
6134     {
6135       while (TREE_CHAIN (params))
6136         params = TREE_CHAIN (params);
6137
6138       if (VOID_TYPE_P (TREE_VALUE (params)))
6139         {
6140           warning (OPT_Wattributes,
6141                    "%qE attribute only applies to variadic functions", name);
6142           *no_add_attrs = true;
6143         }
6144     }
6145
6146   if (args)
6147     {
6148       tree position = TREE_VALUE (args);
6149
6150       if (TREE_CODE (position) != INTEGER_CST)
6151         {
6152           warning (OPT_Wattributes,
6153                    "requested position is not an integer constant");
6154           *no_add_attrs = true;
6155         }
6156       else
6157         {
6158           if (tree_int_cst_lt (position, integer_zero_node))
6159             {
6160               warning (OPT_Wattributes,
6161                        "requested position is less than zero");
6162               *no_add_attrs = true;
6163             }
6164         }
6165     }
6166
6167   return NULL_TREE;
6168 }
6169 \f
6170 /* Check for valid arguments being passed to a function.
6171    ATTRS is a list of attributes.  There are NARGS arguments in the array
6172    ARGARRAY.  TYPELIST is the list of argument types for the function.
6173  */
6174 void
6175 check_function_arguments (tree attrs, int nargs, tree *argarray, tree typelist)
6176 {
6177   /* Check for null being passed in a pointer argument that must be
6178      non-null.  We also need to do this if format checking is enabled.  */
6179
6180   if (warn_nonnull)
6181     check_function_nonnull (attrs, nargs, argarray);
6182
6183   /* Check for errors in format strings.  */
6184
6185   if (warn_format || warn_missing_format_attribute)
6186     check_function_format (attrs, nargs, argarray);
6187
6188   if (warn_format)
6189     check_function_sentinel (attrs, nargs, argarray, typelist);
6190 }
6191
6192 /* Generic argument checking recursion routine.  PARAM is the argument to
6193    be checked.  PARAM_NUM is the number of the argument.  CALLBACK is invoked
6194    once the argument is resolved.  CTX is context for the callback.  */
6195 void
6196 check_function_arguments_recurse (void (*callback)
6197                                   (void *, tree, unsigned HOST_WIDE_INT),
6198                                   void *ctx, tree param,
6199                                   unsigned HOST_WIDE_INT param_num)
6200 {
6201   if ((TREE_CODE (param) == NOP_EXPR || TREE_CODE (param) == CONVERT_EXPR)
6202       && (TYPE_PRECISION (TREE_TYPE (param))
6203           == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (param, 0)))))
6204     {
6205       /* Strip coercion.  */
6206       check_function_arguments_recurse (callback, ctx,
6207                                         TREE_OPERAND (param, 0), param_num);
6208       return;
6209     }
6210
6211   if (TREE_CODE (param) == CALL_EXPR)
6212     {
6213       tree type = TREE_TYPE (TREE_TYPE (CALL_EXPR_FN (param)));
6214       tree attrs;
6215       bool found_format_arg = false;
6216
6217       /* See if this is a call to a known internationalization function
6218          that modifies a format arg.  Such a function may have multiple
6219          format_arg attributes (for example, ngettext).  */
6220
6221       for (attrs = TYPE_ATTRIBUTES (type);
6222            attrs;
6223            attrs = TREE_CHAIN (attrs))
6224         if (is_attribute_p ("format_arg", TREE_PURPOSE (attrs)))
6225           {
6226             tree inner_arg;
6227             tree format_num_expr;
6228             int format_num;
6229             int i;
6230             call_expr_arg_iterator iter;
6231
6232             /* Extract the argument number, which was previously checked
6233                to be valid.  */
6234             format_num_expr = TREE_VALUE (TREE_VALUE (attrs));
6235
6236             gcc_assert (TREE_CODE (format_num_expr) == INTEGER_CST
6237                         && !TREE_INT_CST_HIGH (format_num_expr));
6238
6239             format_num = TREE_INT_CST_LOW (format_num_expr);
6240
6241             for (inner_arg = first_call_expr_arg (param, &iter), i = 1;
6242                  inner_arg != 0;
6243                  inner_arg = next_call_expr_arg (&iter), i++)
6244               if (i == format_num)
6245                 {
6246                   check_function_arguments_recurse (callback, ctx,
6247                                                     inner_arg, param_num);
6248                   found_format_arg = true;
6249                   break;
6250                 }
6251           }
6252
6253       /* If we found a format_arg attribute and did a recursive check,
6254          we are done with checking this argument.  Otherwise, we continue
6255          and this will be considered a non-literal.  */
6256       if (found_format_arg)
6257         return;
6258     }
6259
6260   if (TREE_CODE (param) == COND_EXPR)
6261     {
6262       /* Check both halves of the conditional expression.  */
6263       check_function_arguments_recurse (callback, ctx,
6264                                         TREE_OPERAND (param, 1), param_num);
6265       check_function_arguments_recurse (callback, ctx,
6266                                         TREE_OPERAND (param, 2), param_num);
6267       return;
6268     }
6269
6270   (*callback) (ctx, param, param_num);
6271 }
6272
6273 /* Function to help qsort sort FIELD_DECLs by name order.  */
6274
6275 int
6276 field_decl_cmp (const void *x_p, const void *y_p)
6277 {
6278   const tree *const x = (const tree *const) x_p;
6279   const tree *const y = (const tree *const) y_p;
6280
6281   if (DECL_NAME (*x) == DECL_NAME (*y))
6282     /* A nontype is "greater" than a type.  */
6283     return (TREE_CODE (*y) == TYPE_DECL) - (TREE_CODE (*x) == TYPE_DECL);
6284   if (DECL_NAME (*x) == NULL_TREE)
6285     return -1;
6286   if (DECL_NAME (*y) == NULL_TREE)
6287     return 1;
6288   if (DECL_NAME (*x) < DECL_NAME (*y))
6289     return -1;
6290   return 1;
6291 }
6292
6293 static struct {
6294   gt_pointer_operator new_value;
6295   void *cookie;
6296 } resort_data;
6297
6298 /* This routine compares two fields like field_decl_cmp but using the
6299 pointer operator in resort_data.  */
6300
6301 static int
6302 resort_field_decl_cmp (const void *x_p, const void *y_p)
6303 {
6304   const tree *const x = (const tree *const) x_p;
6305   const tree *const y = (const tree *const) y_p;
6306
6307   if (DECL_NAME (*x) == DECL_NAME (*y))
6308     /* A nontype is "greater" than a type.  */
6309     return (TREE_CODE (*y) == TYPE_DECL) - (TREE_CODE (*x) == TYPE_DECL);
6310   if (DECL_NAME (*x) == NULL_TREE)
6311     return -1;
6312   if (DECL_NAME (*y) == NULL_TREE)
6313     return 1;
6314   {
6315     tree d1 = DECL_NAME (*x);
6316     tree d2 = DECL_NAME (*y);
6317     resort_data.new_value (&d1, resort_data.cookie);
6318     resort_data.new_value (&d2, resort_data.cookie);
6319     if (d1 < d2)
6320       return -1;
6321   }
6322   return 1;
6323 }
6324
6325 /* Resort DECL_SORTED_FIELDS because pointers have been reordered.  */
6326
6327 void
6328 resort_sorted_fields (void *obj,
6329                       void * ARG_UNUSED (orig_obj),
6330                       gt_pointer_operator new_value,
6331                       void *cookie)
6332 {
6333   struct sorted_fields_type *sf = (struct sorted_fields_type *) obj;
6334   resort_data.new_value = new_value;
6335   resort_data.cookie = cookie;
6336   qsort (&sf->elts[0], sf->len, sizeof (tree),
6337          resort_field_decl_cmp);
6338 }
6339
6340 /* Subroutine of c_parse_error.
6341    Return the result of concatenating LHS and RHS. RHS is really
6342    a string literal, its first character is indicated by RHS_START and
6343    RHS_SIZE is its length (including the terminating NUL character).
6344
6345    The caller is responsible for deleting the returned pointer.  */
6346
6347 static char *
6348 catenate_strings (const char *lhs, const char *rhs_start, int rhs_size)
6349 {
6350   const int lhs_size = strlen (lhs);
6351   char *result = XNEWVEC (char, lhs_size + rhs_size);
6352   strncpy (result, lhs, lhs_size);
6353   strncpy (result + lhs_size, rhs_start, rhs_size);
6354   return result;
6355 }
6356
6357 /* Issue the error given by GMSGID, indicating that it occurred before
6358    TOKEN, which had the associated VALUE.  */
6359
6360 void
6361 c_parse_error (const char *gmsgid, enum cpp_ttype token, tree value)
6362 {
6363 #define catenate_messages(M1, M2) catenate_strings ((M1), (M2), sizeof (M2))
6364
6365   char *message = NULL;
6366
6367   if (token == CPP_EOF)
6368     message = catenate_messages (gmsgid, " at end of input");
6369   else if (token == CPP_CHAR || token == CPP_WCHAR)
6370     {
6371       unsigned int val = TREE_INT_CST_LOW (value);
6372       const char *const ell = (token == CPP_CHAR) ? "" : "L";
6373       if (val <= UCHAR_MAX && ISGRAPH (val))
6374         message = catenate_messages (gmsgid, " before %s'%c'");
6375       else
6376         message = catenate_messages (gmsgid, " before %s'\\x%x'");
6377
6378       error (message, ell, val);
6379       free (message);
6380       message = NULL;
6381     }
6382   else if (token == CPP_STRING || token == CPP_WSTRING)
6383     message = catenate_messages (gmsgid, " before string constant");
6384   else if (token == CPP_NUMBER)
6385     message = catenate_messages (gmsgid, " before numeric constant");
6386   else if (token == CPP_NAME)
6387     {
6388       message = catenate_messages (gmsgid, " before %qE");
6389       error (message, value);
6390       free (message);
6391       message = NULL;
6392     }
6393   else if (token == CPP_PRAGMA)
6394     message = catenate_messages (gmsgid, " before %<#pragma%>");
6395   else if (token == CPP_PRAGMA_EOL)
6396     message = catenate_messages (gmsgid, " before end of line");
6397   else if (token < N_TTYPES)
6398     {
6399       message = catenate_messages (gmsgid, " before %qs token");
6400       error (message, cpp_type2name (token));
6401       free (message);
6402       message = NULL;
6403     }
6404   else
6405     error (gmsgid);
6406
6407   if (message)
6408     {
6409       error (message);
6410       free (message);
6411     }
6412 #undef catenate_messages
6413 }
6414
6415 /* Walk a gimplified function and warn for functions whose return value is
6416    ignored and attribute((warn_unused_result)) is set.  This is done before
6417    inlining, so we don't have to worry about that.  */
6418
6419 void
6420 c_warn_unused_result (tree *top_p)
6421 {
6422   tree t = *top_p;
6423   tree_stmt_iterator i;
6424   tree fdecl, ftype;
6425
6426   switch (TREE_CODE (t))
6427     {
6428     case STATEMENT_LIST:
6429       for (i = tsi_start (*top_p); !tsi_end_p (i); tsi_next (&i))
6430         c_warn_unused_result (tsi_stmt_ptr (i));
6431       break;
6432
6433     case COND_EXPR:
6434       c_warn_unused_result (&COND_EXPR_THEN (t));
6435       c_warn_unused_result (&COND_EXPR_ELSE (t));
6436       break;
6437     case BIND_EXPR:
6438       c_warn_unused_result (&BIND_EXPR_BODY (t));
6439       break;
6440     case TRY_FINALLY_EXPR:
6441     case TRY_CATCH_EXPR:
6442       c_warn_unused_result (&TREE_OPERAND (t, 0));
6443       c_warn_unused_result (&TREE_OPERAND (t, 1));
6444       break;
6445     case CATCH_EXPR:
6446       c_warn_unused_result (&CATCH_BODY (t));
6447       break;
6448     case EH_FILTER_EXPR:
6449       c_warn_unused_result (&EH_FILTER_FAILURE (t));
6450       break;
6451
6452     case CALL_EXPR:
6453       if (TREE_USED (t))
6454         break;
6455
6456       /* This is a naked call, as opposed to a CALL_EXPR nested inside
6457          a MODIFY_EXPR.  All calls whose value is ignored should be
6458          represented like this.  Look for the attribute.  */
6459       fdecl = get_callee_fndecl (t);
6460       if (fdecl)
6461         ftype = TREE_TYPE (fdecl);
6462       else
6463         {
6464           ftype = TREE_TYPE (CALL_EXPR_FN (t));
6465           /* Look past pointer-to-function to the function type itself.  */
6466           ftype = TREE_TYPE (ftype);
6467         }
6468
6469       if (lookup_attribute ("warn_unused_result", TYPE_ATTRIBUTES (ftype)))
6470         {
6471           if (fdecl)
6472             warning (0, "%Hignoring return value of %qD, "
6473                      "declared with attribute warn_unused_result",
6474                      EXPR_LOCUS (t), fdecl);
6475           else
6476             warning (0, "%Hignoring return value of function "
6477                      "declared with attribute warn_unused_result",
6478                      EXPR_LOCUS (t));
6479         }
6480       break;
6481
6482     default:
6483       /* Not a container, not a call, or a call whose value is used.  */
6484       break;
6485     }
6486 }
6487
6488 /* Convert a character from the host to the target execution character
6489    set.  cpplib handles this, mostly.  */
6490
6491 HOST_WIDE_INT
6492 c_common_to_target_charset (HOST_WIDE_INT c)
6493 {
6494   /* Character constants in GCC proper are sign-extended under -fsigned-char,
6495      zero-extended under -fno-signed-char.  cpplib insists that characters
6496      and character constants are always unsigned.  Hence we must convert
6497      back and forth.  */
6498   cppchar_t uc = ((cppchar_t)c) & ((((cppchar_t)1) << CHAR_BIT)-1);
6499
6500   uc = cpp_host_to_exec_charset (parse_in, uc);
6501
6502   if (flag_signed_char)
6503     return ((HOST_WIDE_INT)uc) << (HOST_BITS_PER_WIDE_INT - CHAR_TYPE_SIZE)
6504                                >> (HOST_BITS_PER_WIDE_INT - CHAR_TYPE_SIZE);
6505   else
6506     return uc;
6507 }
6508
6509 /* Build the result of __builtin_offsetof.  EXPR is a nested sequence of
6510    component references, with STOP_REF, or alternatively an INDIRECT_REF of
6511    NULL, at the bottom; much like the traditional rendering of offsetof as a
6512    macro.  Returns the folded and properly cast result.  */
6513
6514 static tree
6515 fold_offsetof_1 (tree expr, tree stop_ref)
6516 {
6517   enum tree_code code = PLUS_EXPR;
6518   tree base, off, t;
6519
6520   if (expr == stop_ref && TREE_CODE (expr) != ERROR_MARK)
6521     return size_zero_node;
6522
6523   switch (TREE_CODE (expr))
6524     {
6525     case ERROR_MARK:
6526       return expr;
6527
6528     case VAR_DECL:
6529       error ("cannot apply %<offsetof%> to static data member %qD", expr);
6530       return error_mark_node;
6531
6532     case CALL_EXPR:
6533       error ("cannot apply %<offsetof%> when %<operator[]%> is overloaded");
6534       return error_mark_node;
6535
6536     case INTEGER_CST:
6537       gcc_assert (integer_zerop (expr));
6538       return size_zero_node;
6539
6540     case NOP_EXPR:
6541     case INDIRECT_REF:
6542       base = fold_offsetof_1 (TREE_OPERAND (expr, 0), stop_ref);
6543       gcc_assert (base == error_mark_node || base == size_zero_node);
6544       return base;
6545
6546     case COMPONENT_REF:
6547       base = fold_offsetof_1 (TREE_OPERAND (expr, 0), stop_ref);
6548       if (base == error_mark_node)
6549         return base;
6550
6551       t = TREE_OPERAND (expr, 1);
6552       if (DECL_C_BIT_FIELD (t))
6553         {
6554           error ("attempt to take address of bit-field structure "
6555                  "member %qD", t);
6556           return error_mark_node;
6557         }
6558       off = size_binop (PLUS_EXPR, DECL_FIELD_OFFSET (t),
6559                         size_int (tree_low_cst (DECL_FIELD_BIT_OFFSET (t), 1)
6560                                   / BITS_PER_UNIT));
6561       break;
6562
6563     case ARRAY_REF:
6564       base = fold_offsetof_1 (TREE_OPERAND (expr, 0), stop_ref);
6565       if (base == error_mark_node)
6566         return base;
6567
6568       t = TREE_OPERAND (expr, 1);
6569       if (TREE_CODE (t) == INTEGER_CST && tree_int_cst_sgn (t) < 0)
6570         {
6571           code = MINUS_EXPR;
6572           t = fold_build1 (NEGATE_EXPR, TREE_TYPE (t), t);
6573         }
6574       t = convert (sizetype, t);
6575       off = size_binop (MULT_EXPR, TYPE_SIZE_UNIT (TREE_TYPE (expr)), t);
6576       break;
6577
6578     case COMPOUND_EXPR:
6579       /* Handle static members of volatile structs.  */
6580       t = TREE_OPERAND (expr, 1);
6581       gcc_assert (TREE_CODE (t) == VAR_DECL);
6582       return fold_offsetof_1 (t, stop_ref);
6583
6584     default:
6585       gcc_unreachable ();
6586     }
6587
6588   return size_binop (code, base, off);
6589 }
6590
6591 tree
6592 fold_offsetof (tree expr, tree stop_ref)
6593 {
6594   /* Convert back from the internal sizetype to size_t.  */
6595   return convert (size_type_node, fold_offsetof_1 (expr, stop_ref));
6596 }
6597
6598 /* Print an error message for an invalid lvalue.  USE says
6599    how the lvalue is being used and so selects the error message.  */
6600
6601 void
6602 lvalue_error (enum lvalue_use use)
6603 {
6604   switch (use)
6605     {
6606     case lv_assign:
6607       error ("lvalue required as left operand of assignment");
6608       break;
6609     case lv_increment:
6610       error ("lvalue required as increment operand");
6611       break;
6612     case lv_decrement:
6613       error ("lvalue required as decrement operand");
6614       break;
6615     case lv_addressof:
6616       error ("lvalue required as unary %<&%> operand");
6617       break;
6618     case lv_asm:
6619       error ("lvalue required in asm statement");
6620       break;
6621     default:
6622       gcc_unreachable ();
6623     }
6624 }
6625 \f
6626 /* *PTYPE is an incomplete array.  Complete it with a domain based on
6627    INITIAL_VALUE.  If INITIAL_VALUE is not present, use 1 if DO_DEFAULT
6628    is true.  Return 0 if successful, 1 if INITIAL_VALUE can't be deciphered,
6629    2 if INITIAL_VALUE was NULL, and 3 if INITIAL_VALUE was empty.  */
6630
6631 int
6632 complete_array_type (tree *ptype, tree initial_value, bool do_default)
6633 {
6634   tree maxindex, type, main_type, elt, unqual_elt;
6635   int failure = 0, quals;
6636   hashval_t hashcode = 0;
6637
6638   maxindex = size_zero_node;
6639   if (initial_value)
6640     {
6641       if (TREE_CODE (initial_value) == STRING_CST)
6642         {
6643           int eltsize
6644             = int_size_in_bytes (TREE_TYPE (TREE_TYPE (initial_value)));
6645           maxindex = size_int (TREE_STRING_LENGTH (initial_value)/eltsize - 1);
6646         }
6647       else if (TREE_CODE (initial_value) == CONSTRUCTOR)
6648         {
6649           VEC(constructor_elt,gc) *v = CONSTRUCTOR_ELTS (initial_value);
6650
6651           if (VEC_empty (constructor_elt, v))
6652             {
6653               if (pedantic)
6654                 failure = 3;
6655               maxindex = integer_minus_one_node;
6656             }
6657           else
6658             {
6659               tree curindex;
6660               unsigned HOST_WIDE_INT cnt;
6661               constructor_elt *ce;
6662
6663               if (VEC_index (constructor_elt, v, 0)->index)
6664                 maxindex = fold_convert (sizetype,
6665                                          VEC_index (constructor_elt,
6666                                                     v, 0)->index);
6667               curindex = maxindex;
6668
6669               for (cnt = 1;
6670                    VEC_iterate (constructor_elt, v, cnt, ce);
6671                    cnt++)
6672                 {
6673                   if (ce->index)
6674                     curindex = fold_convert (sizetype, ce->index);
6675                   else
6676                     curindex = size_binop (PLUS_EXPR, curindex, size_one_node);
6677
6678                   if (tree_int_cst_lt (maxindex, curindex))
6679                     maxindex = curindex;
6680                 }
6681             }
6682         }
6683       else
6684         {
6685           /* Make an error message unless that happened already.  */
6686           if (initial_value != error_mark_node)
6687             failure = 1;
6688         }
6689     }
6690   else
6691     {
6692       failure = 2;
6693       if (!do_default)
6694         return failure;
6695     }
6696
6697   type = *ptype;
6698   elt = TREE_TYPE (type);
6699   quals = TYPE_QUALS (strip_array_types (elt));
6700   if (quals == 0)
6701     unqual_elt = elt;
6702   else
6703     unqual_elt = c_build_qualified_type (elt, TYPE_UNQUALIFIED);
6704
6705   /* Using build_distinct_type_copy and modifying things afterward instead
6706      of using build_array_type to create a new type preserves all of the
6707      TYPE_LANG_FLAG_? bits that the front end may have set.  */
6708   main_type = build_distinct_type_copy (TYPE_MAIN_VARIANT (type));
6709   TREE_TYPE (main_type) = unqual_elt;
6710   TYPE_DOMAIN (main_type) = build_index_type (maxindex);
6711   layout_type (main_type);
6712
6713   /* Make sure we have the canonical MAIN_TYPE. */
6714   hashcode = iterative_hash_object (TYPE_HASH (unqual_elt), hashcode);
6715   hashcode = iterative_hash_object (TYPE_HASH (TYPE_DOMAIN (main_type)),
6716                                     hashcode);
6717   main_type = type_hash_canon (hashcode, main_type);
6718
6719   if (quals == 0)
6720     type = main_type;
6721   else
6722     type = c_build_qualified_type (main_type, quals);
6723
6724   *ptype = type;
6725   return failure;
6726 }
6727
6728 \f
6729 /* Used to help initialize the builtin-types.def table.  When a type of
6730    the correct size doesn't exist, use error_mark_node instead of NULL.
6731    The later results in segfaults even when a decl using the type doesn't
6732    get invoked.  */
6733
6734 tree
6735 builtin_type_for_size (int size, bool unsignedp)
6736 {
6737   tree type = lang_hooks.types.type_for_size (size, unsignedp);
6738   return type ? type : error_mark_node;
6739 }
6740
6741 /* A helper function for resolve_overloaded_builtin in resolving the
6742    overloaded __sync_ builtins.  Returns a positive power of 2 if the
6743    first operand of PARAMS is a pointer to a supported data type.
6744    Returns 0 if an error is encountered.  */
6745
6746 static int
6747 sync_resolve_size (tree function, tree params)
6748 {
6749   tree type;
6750   int size;
6751
6752   if (params == NULL)
6753     {
6754       error ("too few arguments to function %qE", function);
6755       return 0;
6756     }
6757
6758   type = TREE_TYPE (TREE_VALUE (params));
6759   if (TREE_CODE (type) != POINTER_TYPE)
6760     goto incompatible;
6761
6762   type = TREE_TYPE (type);
6763   if (!INTEGRAL_TYPE_P (type) && !POINTER_TYPE_P (type))
6764     goto incompatible;
6765
6766   size = tree_low_cst (TYPE_SIZE_UNIT (type), 1);
6767   if (size == 1 || size == 2 || size == 4 || size == 8 || size == 16)
6768     return size;
6769
6770  incompatible:
6771   error ("incompatible type for argument %d of %qE", 1, function);
6772   return 0;
6773 }
6774
6775 /* A helper function for resolve_overloaded_builtin.  Adds casts to
6776    PARAMS to make arguments match up with those of FUNCTION.  Drops
6777    the variadic arguments at the end.  Returns false if some error
6778    was encountered; true on success.  */
6779
6780 static bool
6781 sync_resolve_params (tree orig_function, tree function, tree params)
6782 {
6783   tree arg_types = TYPE_ARG_TYPES (TREE_TYPE (function));
6784   tree ptype;
6785   int number;
6786
6787   /* We've declared the implementation functions to use "volatile void *"
6788      as the pointer parameter, so we shouldn't get any complaints from the
6789      call to check_function_arguments what ever type the user used.  */
6790   arg_types = TREE_CHAIN (arg_types);
6791   ptype = TREE_TYPE (TREE_TYPE (TREE_VALUE (params)));
6792   number = 2;
6793
6794   /* For the rest of the values, we need to cast these to FTYPE, so that we
6795      don't get warnings for passing pointer types, etc.  */
6796   while (arg_types != void_list_node)
6797     {
6798       tree val;
6799
6800       params = TREE_CHAIN (params);
6801       if (params == NULL)
6802         {
6803           error ("too few arguments to function %qE", orig_function);
6804           return false;
6805         }
6806
6807       /* ??? Ideally for the first conversion we'd use convert_for_assignment
6808          so that we get warnings for anything that doesn't match the pointer
6809          type.  This isn't portable across the C and C++ front ends atm.  */
6810       val = TREE_VALUE (params);
6811       val = convert (ptype, val);
6812       val = convert (TREE_VALUE (arg_types), val);
6813       TREE_VALUE (params) = val;
6814
6815       arg_types = TREE_CHAIN (arg_types);
6816       number++;
6817     }
6818
6819   /* The definition of these primitives is variadic, with the remaining
6820      being "an optional list of variables protected by the memory barrier".
6821      No clue what that's supposed to mean, precisely, but we consider all
6822      call-clobbered variables to be protected so we're safe.  */
6823   TREE_CHAIN (params) = NULL;
6824
6825   return true;
6826 }
6827
6828 /* A helper function for resolve_overloaded_builtin.  Adds a cast to
6829    RESULT to make it match the type of the first pointer argument in
6830    PARAMS.  */
6831
6832 static tree
6833 sync_resolve_return (tree params, tree result)
6834 {
6835   tree ptype = TREE_TYPE (TREE_TYPE (TREE_VALUE (params)));
6836   ptype = TYPE_MAIN_VARIANT (ptype);
6837   return convert (ptype, result);
6838 }
6839
6840 /* Some builtin functions are placeholders for other expressions.  This
6841    function should be called immediately after parsing the call expression
6842    before surrounding code has committed to the type of the expression.
6843
6844    FUNCTION is the DECL that has been invoked; it is known to be a builtin.
6845    PARAMS is the argument list for the call.  The return value is non-null
6846    when expansion is complete, and null if normal processing should
6847    continue.  */
6848
6849 tree
6850 resolve_overloaded_builtin (tree function, tree params)
6851 {
6852   enum built_in_function orig_code = DECL_FUNCTION_CODE (function);
6853   switch (DECL_BUILT_IN_CLASS (function))
6854     {
6855     case BUILT_IN_NORMAL:
6856       break;
6857     case BUILT_IN_MD:
6858       if (targetm.resolve_overloaded_builtin)
6859         return targetm.resolve_overloaded_builtin (function, params);
6860       else
6861         return NULL_TREE;
6862     default:
6863       return NULL_TREE;
6864     }
6865
6866   /* Handle BUILT_IN_NORMAL here.  */
6867   switch (orig_code)
6868     {
6869     case BUILT_IN_FETCH_AND_ADD_N:
6870     case BUILT_IN_FETCH_AND_SUB_N:
6871     case BUILT_IN_FETCH_AND_OR_N:
6872     case BUILT_IN_FETCH_AND_AND_N:
6873     case BUILT_IN_FETCH_AND_XOR_N:
6874     case BUILT_IN_FETCH_AND_NAND_N:
6875     case BUILT_IN_ADD_AND_FETCH_N:
6876     case BUILT_IN_SUB_AND_FETCH_N:
6877     case BUILT_IN_OR_AND_FETCH_N:
6878     case BUILT_IN_AND_AND_FETCH_N:
6879     case BUILT_IN_XOR_AND_FETCH_N:
6880     case BUILT_IN_NAND_AND_FETCH_N:
6881     case BUILT_IN_BOOL_COMPARE_AND_SWAP_N:
6882     case BUILT_IN_VAL_COMPARE_AND_SWAP_N:
6883     case BUILT_IN_LOCK_TEST_AND_SET_N:
6884     case BUILT_IN_LOCK_RELEASE_N:
6885       {
6886         int n = sync_resolve_size (function, params);
6887         tree new_function, result;
6888
6889         if (n == 0)
6890           return error_mark_node;
6891
6892         new_function = built_in_decls[orig_code + exact_log2 (n) + 1];
6893         if (!sync_resolve_params (function, new_function, params))
6894           return error_mark_node;
6895
6896         result = build_function_call (new_function, params);
6897         if (orig_code != BUILT_IN_BOOL_COMPARE_AND_SWAP_N
6898             && orig_code != BUILT_IN_LOCK_RELEASE_N)
6899           result = sync_resolve_return (params, result);
6900
6901         return result;
6902       }
6903
6904     default:
6905       return NULL_TREE;
6906     }
6907 }
6908
6909 /* Ignoring their sign, return true if two scalar types are the same.  */
6910 bool
6911 same_scalar_type_ignoring_signedness (tree t1, tree t2)
6912 {
6913   enum tree_code c1 = TREE_CODE (t1), c2 = TREE_CODE (t2);
6914
6915   gcc_assert ((c1 == INTEGER_TYPE || c1 == REAL_TYPE)
6916               && (c2 == INTEGER_TYPE || c2 == REAL_TYPE));
6917
6918   /* Equality works here because c_common_signed_type uses
6919      TYPE_MAIN_VARIANT.  */
6920   return lang_hooks.types.signed_type (t1)
6921     == lang_hooks.types.signed_type (t2);
6922 }
6923
6924 /* Check for missing format attributes on function pointers.  LTYPE is
6925    the new type or left-hand side type.  RTYPE is the old type or
6926    right-hand side type.  Returns TRUE if LTYPE is missing the desired
6927    attribute.  */
6928
6929 bool
6930 check_missing_format_attribute (tree ltype, tree rtype)
6931 {
6932   tree const ttr = TREE_TYPE (rtype), ttl = TREE_TYPE (ltype);
6933   tree ra;
6934
6935   for (ra = TYPE_ATTRIBUTES (ttr); ra; ra = TREE_CHAIN (ra))
6936     if (is_attribute_p ("format", TREE_PURPOSE (ra)))
6937       break;
6938   if (ra)
6939     {
6940       tree la;
6941       for (la = TYPE_ATTRIBUTES (ttl); la; la = TREE_CHAIN (la))
6942         if (is_attribute_p ("format", TREE_PURPOSE (la)))
6943           break;
6944       return !la;
6945     }
6946   else
6947     return false;
6948 }
6949
6950 /* Subscripting with type char is likely to lose on a machine where
6951    chars are signed.  So warn on any machine, but optionally.  Don't
6952    warn for unsigned char since that type is safe.  Don't warn for
6953    signed char because anyone who uses that must have done so
6954    deliberately. Furthermore, we reduce the false positive load by
6955    warning only for non-constant value of type char.  */
6956
6957 void
6958 warn_array_subscript_with_type_char (tree index)
6959 {
6960   if (TYPE_MAIN_VARIANT (TREE_TYPE (index)) == char_type_node
6961       && TREE_CODE (index) != INTEGER_CST)
6962     warning (OPT_Wchar_subscripts, "array subscript has type %<char%>");
6963 }
6964
6965 /* Implement -Wparentheses for the unexpected C precedence rules, to
6966    cover cases like x + y << z which readers are likely to
6967    misinterpret.  We have seen an expression in which CODE is a binary
6968    operator used to combine expressions headed by CODE_LEFT and
6969    CODE_RIGHT.  CODE_LEFT and CODE_RIGHT may be ERROR_MARK, which
6970    means that that side of the expression was not formed using a
6971    binary operator, or it was enclosed in parentheses.  */
6972
6973 void
6974 warn_about_parentheses (enum tree_code code, enum tree_code code_left,
6975                         enum tree_code code_right)
6976 {
6977   if (!warn_parentheses)
6978     return;
6979
6980   if (code == LSHIFT_EXPR || code == RSHIFT_EXPR)
6981     {
6982       if (code_left == PLUS_EXPR || code_left == MINUS_EXPR
6983           || code_right == PLUS_EXPR || code_right == MINUS_EXPR)
6984         warning (OPT_Wparentheses,
6985                  "suggest parentheses around + or - inside shift");
6986     }
6987
6988   if (code == TRUTH_ORIF_EXPR)
6989     {
6990       if (code_left == TRUTH_ANDIF_EXPR
6991           || code_right == TRUTH_ANDIF_EXPR)
6992         warning (OPT_Wparentheses,
6993                  "suggest parentheses around && within ||");
6994     }
6995
6996   if (code == BIT_IOR_EXPR)
6997     {
6998       if (code_left == BIT_AND_EXPR || code_left == BIT_XOR_EXPR
6999           || code_left == PLUS_EXPR || code_left == MINUS_EXPR
7000           || code_right == BIT_AND_EXPR || code_right == BIT_XOR_EXPR
7001           || code_right == PLUS_EXPR || code_right == MINUS_EXPR)
7002         warning (OPT_Wparentheses,
7003                  "suggest parentheses around arithmetic in operand of |");
7004       /* Check cases like x|y==z */
7005       if (TREE_CODE_CLASS (code_left) == tcc_comparison
7006           || TREE_CODE_CLASS (code_right) == tcc_comparison)
7007         warning (OPT_Wparentheses,
7008                  "suggest parentheses around comparison in operand of |");
7009     }
7010
7011   if (code == BIT_XOR_EXPR)
7012     {
7013       if (code_left == BIT_AND_EXPR
7014           || code_left == PLUS_EXPR || code_left == MINUS_EXPR
7015           || code_right == BIT_AND_EXPR
7016           || code_right == PLUS_EXPR || code_right == MINUS_EXPR)
7017         warning (OPT_Wparentheses,
7018                  "suggest parentheses around arithmetic in operand of ^");
7019       /* Check cases like x^y==z */
7020       if (TREE_CODE_CLASS (code_left) == tcc_comparison
7021           || TREE_CODE_CLASS (code_right) == tcc_comparison)
7022         warning (OPT_Wparentheses,
7023                  "suggest parentheses around comparison in operand of ^");
7024     }
7025
7026   if (code == BIT_AND_EXPR)
7027     {
7028       if (code_left == PLUS_EXPR || code_left == MINUS_EXPR
7029           || code_right == PLUS_EXPR || code_right == MINUS_EXPR)
7030         warning (OPT_Wparentheses,
7031                  "suggest parentheses around + or - in operand of &");
7032       /* Check cases like x&y==z */
7033       if (TREE_CODE_CLASS (code_left) == tcc_comparison
7034           || TREE_CODE_CLASS (code_right) == tcc_comparison)
7035         warning (OPT_Wparentheses,
7036                  "suggest parentheses around comparison in operand of &");
7037     }
7038
7039   if (code == EQ_EXPR || code == NE_EXPR)
7040     {
7041       if (TREE_CODE_CLASS (code_left) == tcc_comparison
7042           || TREE_CODE_CLASS (code_right) == tcc_comparison)
7043         warning (OPT_Wparentheses,
7044                  "suggest parentheses around comparison in operand of %s",
7045                  code == EQ_EXPR ? "==" : "!=");
7046     }
7047   else if (TREE_CODE_CLASS (code) == tcc_comparison)
7048     {
7049       if ((TREE_CODE_CLASS (code_left) == tcc_comparison
7050            && code_left != NE_EXPR && code_left != EQ_EXPR)
7051           || (TREE_CODE_CLASS (code_right) == tcc_comparison
7052               && code_right != NE_EXPR && code_right != EQ_EXPR))
7053         warning (OPT_Wparentheses, "comparisons like X<=Y<=Z do not "
7054                  "have their mathematical meaning");
7055     }
7056 }
7057
7058 /* If LABEL (a LABEL_DECL) has not been used, issue a warning.  */
7059
7060 void
7061 warn_for_unused_label (tree label)
7062 {
7063   if (!TREE_USED (label))
7064     {
7065       if (DECL_INITIAL (label))
7066         warning (OPT_Wunused_label, "label %q+D defined but not used", label);
7067       else
7068         warning (OPT_Wunused_label, "label %q+D declared but not defined", label);
7069     }
7070 }
7071
7072 #ifndef TARGET_HAS_TARGETCM
7073 struct gcc_targetcm targetcm = TARGETCM_INITIALIZER;
7074 #endif
7075
7076 /* Warn for division by zero according to the value of DIVISOR.  */
7077
7078 void
7079 warn_for_div_by_zero (tree divisor)
7080 {
7081   /* If DIVISOR is zero, and has integral type, issue a warning about
7082      division by zero.  Do not issue a warning if DIVISOR has a
7083      floating-point type, since we consider 0.0/0.0 a valid way of
7084      generating a NaN.  */
7085   if (skip_evaluation == 0 && integer_zerop (divisor))
7086     warning (OPT_Wdiv_by_zero, "division by zero");
7087 }
7088
7089 #include "gt-c-common.h"