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
 560 static void check_function_nonnull (tree, int, tree *);
 561 static void check_nonnull_arg (void *, tree, unsigned HOST_WIDE_INT);
 562 static bool nonnull_check_p (tree, unsigned HOST_WIDE_INT);
 563 static bool get_nonnull_operand (tree, unsigned HOST_WIDE_INT *);
 564 static int resort_field_decl_cmp (const void *, const void *);
 565
 566 /* Table of machine-independent attributes common to all C-like languages.  */
 567 const struct attribute_spec c_common_attribute_table[] =
 568 {
 569   /* { name, min_len, max_len, decl_req, type_req, fn_type_req, handler } */
 570   { "packed",                 0, 0, false, false, false,
 571                               handle_packed_attribute },
 572   { "nocommon",               0, 0, true,  false, false,
 573                               handle_nocommon_attribute },
 574   { "common",                 0, 0, true,  false, false,
 575                               handle_common_attribute },
 576   /* FIXME: logically, noreturn attributes should be listed as
 577      "false, true, true" and apply to function types.  But implementing this
 578      would require all the places in the compiler that use TREE_THIS_VOLATILE
 579      on a decl to identify non-returning functions to be located and fixed
 580      to check the function type instead.  */
 581   { "noreturn",               0, 0, true,  false, false,
 582                               handle_noreturn_attribute },
 583   { "volatile",               0, 0, true,  false, false,
 584                               handle_noreturn_attribute },
 585   { "noinline",               0, 0, true,  false, false,
 586                               handle_noinline_attribute },
 587   { "always_inline",          0, 0, true,  false, false,
 588                               handle_always_inline_attribute },
 589   { "gnu_inline",             0, 0, true,  false, false,
 590                               handle_gnu_inline_attribute },
 591   { "flatten",                0, 0, true,  false, false,
 592                               handle_flatten_attribute },
 593   { "used",                   0, 0, true,  false, false,
 594                               handle_used_attribute },
 595   { "unused",                 0, 0, false, false, false,
 596                               handle_unused_attribute },
 597   { "externally_visible",     0, 0, true,  false, false,
 598                               handle_externally_visible_attribute },
 599   /* The same comments as for noreturn attributes apply to const ones.  */
 600   { "const",                  0, 0, true,  false, false,
 601                               handle_const_attribute },
 602   { "transparent_union",      0, 0, false, false, false,
 603                               handle_transparent_union_attribute },
 604   { "constructor",            0, 1, true,  false, false,
 605                               handle_constructor_attribute },
 606   { "destructor",             0, 1, true,  false, false,
 607                               handle_destructor_attribute },
 608   { "mode",                   1, 1, false,  true, false,
 609                               handle_mode_attribute },
 610   { "section",                1, 1, true,  false, false,
 611                               handle_section_attribute },
 612   { "aligned",                0, 1, false, false, false,
 613                               handle_aligned_attribute },
 614   { "weak",                   0, 0, true,  false, false,
 615                               handle_weak_attribute },
 616   { "alias",                  1, 1, true,  false, false,
 617                               handle_alias_attribute },
 618   { "weakref",                0, 1, true,  false, false,
 619                               handle_weakref_attribute },
 620   { "no_instrument_function", 0, 0, true,  false, false,
 621                               handle_no_instrument_function_attribute },
 622   { "malloc",                 0, 0, true,  false, false,
 623                               handle_malloc_attribute },
 624   { "returns_twice",          0, 0, true,  false, false,
 625                               handle_returns_twice_attribute },
 626   { "no_stack_limit",         0, 0, true,  false, false,
 627                               handle_no_limit_stack_attribute },
 628   { "pure",                   0, 0, true,  false, false,
 629                               handle_pure_attribute },
 630   /* For internal use (marking of builtins) only.  The name contains space
 631      to prevent its usage in source code.  */
 632   { "no vops",                0, 0, true,  false, false,
 633                               handle_novops_attribute },
 634   { "deprecated",             0, 0, false, false, false,
 635                               handle_deprecated_attribute },
 636   { "vector_size",            1, 1, false, true, false,
 637                               handle_vector_size_attribute },
 638   { "visibility",             1, 1, false, false, false,
 639                               handle_visibility_attribute },
 640   { "tls_model",              1, 1, true,  false, false,
 641                               handle_tls_model_attribute },
 642   { "nonnull",                0, -1, false, true, true,
 643                               handle_nonnull_attribute },
 644   { "nothrow",                0, 0, true,  false, false,
 645                               handle_nothrow_attribute },
 646   { "may_alias",              0, 0, false, true, false, NULL },
 647   { "cleanup",                1, 1, true, false, false,
 648                               handle_cleanup_attribute },
 649   { "warn_unused_result",     0, 0, false, true, true,
 650                               handle_warn_unused_result_attribute },
 651   { "sentinel",               0, 1, false, true, true,
 652                               handle_sentinel_attribute },
 653   { "cold",                   0, 0, true,  false, false,
 654                               handle_cold_attribute },
 655   { "hot",                    0, 0, true,  false, false,
 656                               handle_hot_attribute },
 657   { NULL,                     0, 0, false, false, false, NULL }
 658 };
 659
 660 /* Give the specifications for the format attributes, used by C and all
 661    descendants.  */
 662
 663 const struct attribute_spec c_common_format_attribute_table[] =
 664 {
 665   /* { name, min_len, max_len, decl_req, type_req, fn_type_req, handler } */
 666   { "format",                 3, 3, false, true,  true,
 667                               handle_format_attribute },
 668   { "format_arg",             1, 1, false, true,  true,
 669                               handle_format_arg_attribute },
 670   { NULL,                     0, 0, false, false, false, NULL }
 671 };
 672
 673 /* Functions called automatically at the beginning and end of execution.  */
 674
 675 tree static_ctors;
 676 tree static_dtors;
 677
 678 /* Push current bindings for the function name VAR_DECLS.  */
 679
 680 void
 681 start_fname_decls (void)
 682 {
 683   unsigned ix;
 684   tree saved = NULL_TREE;
 685
 686   for (ix = 0; fname_vars[ix].decl; ix++)
 687     {
 688       tree decl = *fname_vars[ix].decl;
 689
 690       if (decl)
 691         {
 692           saved = tree_cons (decl, build_int_cst (NULL_TREE, ix), saved);
 693           *fname_vars[ix].decl = NULL_TREE;
 694         }
 695     }
 696   if (saved || saved_function_name_decls)
 697     /* Normally they'll have been NULL, so only push if we've got a
 698        stack, or they are non-NULL.  */
 699     saved_function_name_decls = tree_cons (saved, NULL_TREE,
 700                                            saved_function_name_decls);
 701 }
 702
 703 /* Finish up the current bindings, adding them into the current function's
 704    statement tree.  This must be done _before_ finish_stmt_tree is called.
 705    If there is no current function, we must be at file scope and no statements
 706    are involved. Pop the previous bindings.  */
 707
 708 void
 709 finish_fname_decls (void)
 710 {
 711   unsigned ix;
 712   tree stmts = NULL_TREE;
 713   tree stack = saved_function_name_decls;
 714
 715   for (; stack && TREE_VALUE (stack); stack = TREE_CHAIN (stack))
 716     append_to_statement_list (TREE_VALUE (stack), &stmts);
 717
 718   if (stmts)
 719     {
 720       tree *bodyp = &DECL_SAVED_TREE (current_function_decl);
 721
 722       if (TREE_CODE (*bodyp) == BIND_EXPR)
 723         bodyp = &BIND_EXPR_BODY (*bodyp);
 724
 725       append_to_statement_list_force (*bodyp, &stmts);
 726       *bodyp = stmts;
 727     }
 728
 729   for (ix = 0; fname_vars[ix].decl; ix++)
 730     *fname_vars[ix].decl = NULL_TREE;
 731
 732   if (stack)
 733     {
 734       /* We had saved values, restore them.  */
 735       tree saved;
 736
 737       for (saved = TREE_PURPOSE (stack); saved; saved = TREE_CHAIN (saved))
 738         {
 739           tree decl = TREE_PURPOSE (saved);
 740           unsigned ix = TREE_INT_CST_LOW (TREE_VALUE (saved));
 741
 742           *fname_vars[ix].decl = decl;
 743         }
 744       stack = TREE_CHAIN (stack);
 745     }
 746   saved_function_name_decls = stack;
 747 }
 748
 749 /* Return the text name of the current function, suitably prettified
 750    by PRETTY_P.  Return string must be freed by caller.  */
 751
 752 const char *
 753 fname_as_string (int pretty_p)
 754 {
 755   const char *name = "top level";
 756   char *namep;
 757   int vrb = 2;
 758
 759   if (!pretty_p)
 760     {
 761       name = "";
 762       vrb = 0;
 763     }
 764
 765   if (current_function_decl)
 766     name = lang_hooks.decl_printable_name (current_function_decl, vrb);
 767
 768   if (c_lex_string_translate)
 769     {
 770       int len = strlen (name) + 3; /* Two for '"'s.  One for NULL.  */
 771       cpp_string cstr = { 0, 0 }, strname;
 772
 773       namep = XNEWVEC (char, len);
 774       snprintf (namep, len, "\"%s\"", name);
 775       strname.text = (unsigned char *) namep;
 776       strname.len = len - 1;
 777
 778       if (cpp_interpret_string (parse_in, &strname, 1, &cstr, false))
 779         {
 780           XDELETEVEC (namep);
 781           return (char *) cstr.text;
 782         }
 783     }
 784   else
 785     namep = xstrdup (name);
 786
 787   return namep;
 788 }
 789
 790 /* Expand DECL if it declares an entity not handled by the
 791    common code.  */
 792
 793 int
 794 c_expand_decl (tree decl)
 795 {
 796   if (TREE_CODE (decl) == VAR_DECL && !TREE_STATIC (decl))
 797     {
 798       /* Let the back-end know about this variable.  */
 799       if (!anon_aggr_type_p (TREE_TYPE (decl)))
 800         emit_local_var (decl);
 801       else
 802         expand_anon_union_decl (decl, NULL_TREE,
 803                                 DECL_ANON_UNION_ELEMS (decl));
 804     }
 805   else
 806     return 0;
 807
 808   return 1;
 809 }
 810
 811
 812 /* Return the VAR_DECL for a const char array naming the current
 813    function. If the VAR_DECL has not yet been created, create it
 814    now. RID indicates how it should be formatted and IDENTIFIER_NODE
 815    ID is its name (unfortunately C and C++ hold the RID values of
 816    keywords in different places, so we can't derive RID from ID in
 817    this language independent code.  */
 818
 819 tree
 820 fname_decl (unsigned int rid, tree id)
 821 {
 822   unsigned ix;
 823   tree decl = NULL_TREE;
 824
 825   for (ix = 0; fname_vars[ix].decl; ix++)
 826     if (fname_vars[ix].rid == rid)
 827       break;
 828
 829   decl = *fname_vars[ix].decl;
 830   if (!decl)
 831     {
 832       /* If a tree is built here, it would normally have the lineno of
 833          the current statement.  Later this tree will be moved to the
 834          beginning of the function and this line number will be wrong.
 835          To avoid this problem set the lineno to 0 here; that prevents
 836          it from appearing in the RTL.  */
 837       tree stmts;
 838       location_t saved_location = input_location;
 839 #ifdef USE_MAPPED_LOCATION
 840       input_location = UNKNOWN_LOCATION;
 841 #else
 842       input_line = 0;
 843 #endif
 844
 845       stmts = push_stmt_list ();
 846       decl = (*make_fname_decl) (id, fname_vars[ix].pretty);
 847       stmts = pop_stmt_list (stmts);
 848       if (!IS_EMPTY_STMT (stmts))
 849         saved_function_name_decls
 850           = tree_cons (decl, stmts, saved_function_name_decls);
 851       *fname_vars[ix].decl = decl;
 852       input_location = saved_location;
 853     }
 854   if (!ix && !current_function_decl)
 855     pedwarn ("%qD is not defined outside of function scope", decl);
 856
 857   return decl;
 858 }
 859
 860 /* Given a STRING_CST, give it a suitable array-of-chars data type.  */
 861
 862 tree
 863 fix_string_type (tree value)
 864 {
 865   const int wchar_bytes = TYPE_PRECISION (wchar_type_node) / BITS_PER_UNIT;
 866   const int wide_flag = TREE_TYPE (value) == wchar_array_type_node;
 867   int length = TREE_STRING_LENGTH (value);
 868   int nchars;
 869   tree e_type, i_type, a_type;
 870
 871   /* Compute the number of elements, for the array type.  */
 872   nchars = wide_flag ? length / wchar_bytes : length;
 873
 874   /* C89 2.2.4.1, C99 5.2.4.1 (Translation limits).  The analogous
 875      limit in C++98 Annex B is very large (65536) and is not normative,
 876      so we do not diagnose it (warn_overlength_strings is forced off
 877      in c_common_post_options).  */
 878   if (warn_overlength_strings)
 879     {
 880       const int nchars_max = flag_isoc99 ? 4095 : 509;
 881       const int relevant_std = flag_isoc99 ? 99 : 90;
 882       if (nchars - 1 > nchars_max)
 883         /* Translators: The %d after 'ISO C' will be 90 or 99.  Do not
 884            separate the %d from the 'C'.  'ISO' should not be
 885            translated, but it may be moved after 'C%d' in languages
 886            where modifiers follow nouns.  */
 887         pedwarn ("string length %qd is greater than the length %qd "
 888                  "ISO C%d compilers are required to support",
 889                  nchars - 1, nchars_max, relevant_std);
 890     }
 891
 892   /* Create the array type for the string constant.  The ISO C++
 893      standard says that a string literal has type `const char[N]' or
 894      `const wchar_t[N]'.  We use the same logic when invoked as a C
 895      front-end with -Wwrite-strings.
 896      ??? We should change the type of an expression depending on the
 897      state of a warning flag.  We should just be warning -- see how
 898      this is handled in the C++ front-end for the deprecated implicit
 899      conversion from string literals to `char*' or `wchar_t*'.
 900
 901      The C++ front end relies on TYPE_MAIN_VARIANT of a cv-qualified
 902      array type being the unqualified version of that type.
 903      Therefore, if we are constructing an array of const char, we must
 904      construct the matching unqualified array type first.  The C front
 905      end does not require this, but it does no harm, so we do it
 906      unconditionally.  */
 907   e_type = wide_flag ? wchar_type_node : char_type_node;
 908   i_type = build_index_type (build_int_cst (NULL_TREE, nchars - 1));
 909   a_type = build_array_type (e_type, i_type);
 910   if (c_dialect_cxx() || warn_write_strings)
 911     a_type = c_build_qualified_type (a_type, TYPE_QUAL_CONST);
 912
 913   TREE_TYPE (value) = a_type;
 914   TREE_CONSTANT (value) = 1;
 915   TREE_INVARIANT (value) = 1;
 916   TREE_READONLY (value) = 1;
 917   TREE_STATIC (value) = 1;
 918   return value;
 919 }
 920 \f
 921 /* Print a warning if a constant expression had overflow in folding.
 922    Invoke this function on every expression that the language
 923    requires to be a constant expression.
 924    Note the ANSI C standard says it is erroneous for a
 925    constant expression to overflow.  */
 926
 927 void
 928 constant_expression_warning (tree value)
 929 {
 930   if ((TREE_CODE (value) == INTEGER_CST || TREE_CODE (value) == REAL_CST
 931        || TREE_CODE (value) == VECTOR_CST
 932        || TREE_CODE (value) == COMPLEX_CST)
 933       && TREE_OVERFLOW (value)
 934       && warn_overflow
 935       && pedantic)
 936     pedwarn ("overflow in constant expression");
 937 }
 938
 939 /* Print a warning if an expression had overflow in folding and its
 940    operands hadn't.
 941
 942    Invoke this function on every expression that
 943    (1) appears in the source code, and
 944    (2) is a constant expression that overflowed, and
 945    (3) is not already checked by convert_and_check;
 946    however, do not invoke this function on operands of explicit casts
 947    or when the expression is the result of an operator and any operand
 948    already overflowed.  */
 949
 950 void
 951 overflow_warning (tree value)
 952 {
 953   if (skip_evaluation) return;
 954
 955   switch (TREE_CODE (value))
 956     {
 957     case INTEGER_CST:
 958       warning (OPT_Woverflow, "integer overflow in expression");
 959       break;
 960
 961     case REAL_CST:
 962       warning (OPT_Woverflow, "floating point overflow in expression");
 963       break;
 964
 965     case VECTOR_CST:
 966       warning (OPT_Woverflow, "vector overflow in expression");
 967       break;
 968
 969     case COMPLEX_CST:
 970       if (TREE_CODE (TREE_REALPART (value)) == INTEGER_CST)
 971         warning (OPT_Woverflow, "complex integer overflow in expression");
 972       else if (TREE_CODE (TREE_REALPART (value)) == REAL_CST)
 973         warning (OPT_Woverflow, "complex floating point overflow in expression");
 974       break;
 975
 976     default:
 977       break;
 978     }
 979 }
 980
 981
 982 /* Warn about use of a logical || / && operator being used in a
 983    context where it is likely that the bitwise equivalent was intended
 984    by the programmer. CODE is the TREE_CODE of the operator, ARG1
 985    and ARG2 the arguments.  */
 986
 987 void
 988 warn_logical_operator (enum tree_code code, tree arg1, tree
 989     arg2)
 990 {
 991   switch (code)
 992     {
 993       case TRUTH_ANDIF_EXPR:
 994       case TRUTH_ORIF_EXPR:
 995       case TRUTH_OR_EXPR:
 996       case TRUTH_AND_EXPR:
 997         if (!TREE_NO_WARNING (arg1)
 998             && INTEGRAL_TYPE_P (TREE_TYPE (arg1))
 999             && !CONSTANT_CLASS_P (arg1)
1000             && TREE_CODE (arg2) == INTEGER_CST
1001             && !integer_zerop (arg2))
1002           {
1003             warning (OPT_Wlogical_op,
1004                      "logical %<%s%> with non-zero constant "
1005                      "will always evaluate as true",
1006                      ((code == TRUTH_ANDIF_EXPR)
1007                       || (code == TRUTH_AND_EXPR)) ? "&&" : "||");
1008             TREE_NO_WARNING (arg1) = true;
1009           }
1010         break;
1011       default:
1012         break;
1013     }
1014 }
1015
1016
1017 /* Print a warning about casts that might indicate violation
1018    of strict aliasing rules if -Wstrict-aliasing is used and
1019    strict aliasing mode is in effect. OTYPE is the original
1020    TREE_TYPE of EXPR, and TYPE the type we're casting to. */
1021
1022 void
1023 strict_aliasing_warning (tree otype, tree type, tree expr)
1024 {
1025   if (flag_strict_aliasing && warn_strict_aliasing
1026       && POINTER_TYPE_P (type) && POINTER_TYPE_P (otype)
1027       && TREE_CODE (expr) == ADDR_EXPR
1028       && (DECL_P (TREE_OPERAND (expr, 0))
1029           || handled_component_p (TREE_OPERAND (expr, 0)))
1030       && !VOID_TYPE_P (TREE_TYPE (type)))
1031     {
1032       /* Casting the address of an object to non void pointer. Warn
1033          if the cast breaks type based aliasing.  */
1034       if (!COMPLETE_TYPE_P (TREE_TYPE (type)))
1035         warning (OPT_Wstrict_aliasing, "type-punning to incomplete type "
1036                  "might break strict-aliasing rules");
1037       else
1038         {
1039           HOST_WIDE_INT set1 = get_alias_set (TREE_TYPE (TREE_OPERAND (expr, 0)));
1040           HOST_WIDE_INT set2 = get_alias_set (TREE_TYPE (type));
1041
1042           if (!alias_sets_conflict_p (set1, set2))
1043             warning (OPT_Wstrict_aliasing, "dereferencing type-punned "
1044                      "pointer will break strict-aliasing rules");
1045           else if (warn_strict_aliasing > 1
1046                   && !alias_sets_might_conflict_p (set1, set2))
1047             warning (OPT_Wstrict_aliasing, "dereferencing type-punned "
1048                      "pointer might break strict-aliasing rules");
1049         }
1050     }
1051 }
1052
1053 /* Print a warning about if (); or if () .. else; constructs
1054    via the special empty statement node that we create.  INNER_THEN
1055    and INNER_ELSE are the statement lists of the if and the else
1056    block.  */
1057
1058 void
1059 empty_if_body_warning (tree inner_then, tree inner_else)
1060 {
1061   if (TREE_CODE (inner_then) == STATEMENT_LIST
1062       && STATEMENT_LIST_TAIL (inner_then))
1063     inner_then = STATEMENT_LIST_TAIL (inner_then)->stmt;
1064
1065   if (inner_else && TREE_CODE (inner_else) == STATEMENT_LIST
1066       && STATEMENT_LIST_TAIL (inner_else))
1067     inner_else = STATEMENT_LIST_TAIL (inner_else)->stmt;
1068
1069   if (IS_EMPTY_STMT (inner_then) && !inner_else)
1070     warning (OPT_Wempty_body, "%Hsuggest braces around empty body "
1071              "in an %<if%> statement", EXPR_LOCUS (inner_then));
1072
1073   else if (inner_else && IS_EMPTY_STMT (inner_else))
1074     warning (OPT_Wempty_body, "%Hsuggest braces around empty body "
1075              "in an %<else%> statement", EXPR_LOCUS (inner_else));
1076 }
1077
1078 /* Warn for unlikely, improbable, or stupid DECL declarations
1079    of `main'.  */
1080
1081 void
1082 check_main_parameter_types (tree decl)
1083 {
1084   tree args;
1085   int argct = 0;
1086
1087   for (args = TYPE_ARG_TYPES (TREE_TYPE (decl)); args;
1088       args = TREE_CHAIN (args))
1089    {
1090      tree type = args ? TREE_VALUE (args) : 0;
1091
1092      if (type == void_type_node || type == error_mark_node )
1093        break;
1094
1095      ++argct;
1096      switch (argct)
1097        {
1098        case 1:
1099          if (TYPE_MAIN_VARIANT (type) != integer_type_node)
1100            pedwarn ("first argument of %q+D should be %<int%>", decl);
1101          break;
1102
1103        case 2:
1104          if (TREE_CODE (type) != POINTER_TYPE
1105              || TREE_CODE (TREE_TYPE (type)) != POINTER_TYPE
1106              || (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (type)))
1107                  != char_type_node))
1108            pedwarn ("second argument of %q+D should be %<char **%>",
1109                     decl);
1110          break;
1111
1112        case 3:
1113          if (TREE_CODE (type) != POINTER_TYPE
1114              || TREE_CODE (TREE_TYPE (type)) != POINTER_TYPE
1115              || (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (type)))
1116                  != char_type_node))
1117            pedwarn ("third argument of %q+D should probably be "
1118                     "%<char **%>", decl);
1119          break;
1120        }
1121    }
1122
1123   /* It is intentional that this message does not mention the third
1124     argument because it's only mentioned in an appendix of the
1125     standard.  */
1126   if (argct > 0 && (argct < 2 || argct > 3))
1127    pedwarn ("%q+D takes only zero or two arguments", decl);
1128 }
1129
1130 /* True if vector types T1 and T2 can be converted to each other
1131    without an explicit cast.  If EMIT_LAX_NOTE is true, and T1 and T2
1132    can only be converted with -flax-vector-conversions yet that is not
1133    in effect, emit a note telling the user about that option if such
1134    a note has not previously been emitted.  */
1135 bool
1136 vector_types_convertible_p (tree t1, tree t2, bool emit_lax_note)
1137 {
1138   static bool emitted_lax_note = false;
1139   bool convertible_lax;
1140
1141   if ((targetm.vector_opaque_p (t1) || targetm.vector_opaque_p (t2))
1142       && tree_int_cst_equal (TYPE_SIZE (t1), TYPE_SIZE (t2)))
1143     return true;
1144
1145   convertible_lax =
1146     (tree_int_cst_equal (TYPE_SIZE (t1), TYPE_SIZE (t2))
1147      && (TREE_CODE (TREE_TYPE (t1)) != REAL_TYPE ||
1148          TYPE_PRECISION (t1) == TYPE_PRECISION (t2))
1149      && (INTEGRAL_TYPE_P (TREE_TYPE (t1))
1150          == INTEGRAL_TYPE_P (TREE_TYPE (t2))));
1151
1152   if (!convertible_lax || flag_lax_vector_conversions)
1153     return convertible_lax;
1154
1155   if (TYPE_VECTOR_SUBPARTS (t1) == TYPE_VECTOR_SUBPARTS (t2)
1156       && comptypes (TREE_TYPE (t1), TREE_TYPE (t2)))
1157     return true;
1158
1159   if (emit_lax_note && !emitted_lax_note)
1160     {
1161       emitted_lax_note = true;
1162       inform ("use -flax-vector-conversions to permit "
1163               "conversions between vectors with differing "
1164               "element types or numbers of subparts");
1165     }
1166
1167   return false;
1168 }
1169
1170 /* Warns if the conversion of EXPR to TYPE may alter a value.
1171    This function is called from convert_and_check.  */
1172
1173 static void
1174 conversion_warning (tree type, tree expr)
1175 {
1176   bool give_warning = false;
1177
1178   unsigned int formal_prec = TYPE_PRECISION (type);
1179
1180   if (TREE_CODE (expr) == REAL_CST || TREE_CODE (expr) == INTEGER_CST)
1181     {
1182       /* Warn for real constant that is not an exact integer converted
1183          to integer type.  */
1184       if (TREE_CODE (TREE_TYPE (expr)) == REAL_TYPE
1185           && TREE_CODE (type) == INTEGER_TYPE)
1186         {
1187           if (!real_isinteger (TREE_REAL_CST_PTR (expr), TYPE_MODE (TREE_TYPE (expr))))
1188             give_warning = true;
1189         }
1190       /* Warn for an integer constant that does not fit into integer type.  */
1191       else if (TREE_CODE (TREE_TYPE (expr)) == INTEGER_TYPE
1192                && TREE_CODE (type) == INTEGER_TYPE
1193                && !int_fits_type_p (expr, type))
1194         {
1195           if (TYPE_UNSIGNED (type) && !TYPE_UNSIGNED (TREE_TYPE (expr)))
1196             warning (OPT_Wconversion,
1197                      "negative integer implicitly converted to unsigned type");
1198           else
1199             give_warning = true;
1200         }
1201       else if (TREE_CODE (type) == REAL_TYPE)
1202         {
1203           /* Warn for an integer constant that does not fit into real type.  */
1204           if (TREE_CODE (TREE_TYPE (expr)) == INTEGER_TYPE)
1205             {
1206               REAL_VALUE_TYPE a = real_value_from_int_cst (0, expr);
1207               if (!exact_real_truncate (TYPE_MODE (type), &a))
1208                 give_warning = true;
1209             }
1210           /* Warn for a real constant that does not fit into a smaller
1211              real type.  */
1212           else if (TREE_CODE (TREE_TYPE (expr)) == REAL_TYPE
1213                    && formal_prec < TYPE_PRECISION (TREE_TYPE (expr)))
1214             {
1215               REAL_VALUE_TYPE a = TREE_REAL_CST (expr);
1216               if (!exact_real_truncate (TYPE_MODE (type), &a))
1217                 give_warning = true;
1218             }
1219         }
1220
1221       if (give_warning)
1222         warning (OPT_Wconversion,
1223                  "conversion to %qT alters %qT constant value",
1224                  type, TREE_TYPE (expr));
1225     }
1226   else /* 'expr' is not a constant.  */
1227     {
1228       /* Warn for real types converted to integer types.  */
1229       if (TREE_CODE (TREE_TYPE (expr)) == REAL_TYPE
1230           && TREE_CODE (type) == INTEGER_TYPE)
1231         give_warning = true;
1232
1233       else if (TREE_CODE (TREE_TYPE (expr)) == INTEGER_TYPE
1234                && TREE_CODE (type) == INTEGER_TYPE)
1235         {
1236           /* Warn for integer types converted to smaller integer types.  */
1237           if (formal_prec < TYPE_PRECISION (TREE_TYPE (expr))
1238               /* When they are the same width but different signedness,
1239                  then the value may change.  */
1240               || (formal_prec == TYPE_PRECISION (TREE_TYPE (expr))
1241                   && TYPE_UNSIGNED (TREE_TYPE (expr)) != TYPE_UNSIGNED (type))
1242               /* Even when converted to a bigger type, if the type is
1243                  unsigned but expr is signed, then negative values
1244                  will be changed.  */
1245               || (TYPE_UNSIGNED (type) && !TYPE_UNSIGNED (TREE_TYPE (expr))))
1246             give_warning = true;
1247         }
1248
1249       /* Warn for integer types converted to real types if and only if
1250          all the range of values of the integer type cannot be
1251          represented by the real type.  */
1252       else if (TREE_CODE (TREE_TYPE (expr)) == INTEGER_TYPE
1253                && TREE_CODE (type) == REAL_TYPE)
1254         {
1255           tree type_low_bound = TYPE_MIN_VALUE (TREE_TYPE (expr));
1256           tree type_high_bound = TYPE_MAX_VALUE (TREE_TYPE (expr));
1257           REAL_VALUE_TYPE real_low_bound = real_value_from_int_cst (0, type_low_bound);
1258           REAL_VALUE_TYPE real_high_bound = real_value_from_int_cst (0, type_high_bound);
1259
1260           if (!exact_real_truncate (TYPE_MODE (type), &real_low_bound)
1261               || !exact_real_truncate (TYPE_MODE (type), &real_high_bound))
1262             give_warning = true;
1263         }
1264
1265       /* Warn for real types converted to smaller real types.  */
1266       else if (TREE_CODE (TREE_TYPE (expr)) == REAL_TYPE
1267                && TREE_CODE (type) == REAL_TYPE
1268                && formal_prec < TYPE_PRECISION (TREE_TYPE (expr)))
1269         give_warning = true;
1270
1271
1272       if (give_warning)
1273         warning (OPT_Wconversion,
1274                  "conversion to %qT from %qT may alter its value",
1275                  type, TREE_TYPE (expr));
1276     }
1277 }
1278
1279 /* Convert EXPR to TYPE, warning about conversion problems with constants.
1280    Invoke this function on every expression that is converted implicitly,
1281    i.e. because of language rules and not because of an explicit cast.  */
1282
1283 tree
1284 convert_and_check (tree type, tree expr)
1285 {
1286   tree result;
1287
1288   if (TREE_TYPE (expr) == type)
1289     return expr;
1290
1291   result = convert (type, expr);
1292
1293   if (skip_evaluation || TREE_OVERFLOW_P (expr))
1294     return result;
1295
1296   if (TREE_CODE (expr) == INTEGER_CST
1297       && (TREE_CODE (type) == INTEGER_TYPE
1298           || TREE_CODE (type) == ENUMERAL_TYPE)
1299       && !int_fits_type_p (expr, type))
1300     {
1301       /* Do not diagnose overflow in a constant expression merely
1302          because a conversion overflowed.  */
1303       if (TREE_OVERFLOW (result))
1304         TREE_OVERFLOW (result) = TREE_OVERFLOW (expr);
1305
1306       if (TYPE_UNSIGNED (type))
1307         {
1308           /* This detects cases like converting -129 or 256 to
1309              unsigned char.  */
1310           if (!int_fits_type_p (expr, c_common_signed_type (type)))
1311             warning (OPT_Woverflow,
1312                      "large integer implicitly truncated to unsigned type");
1313           else if (warn_conversion)
1314             conversion_warning (type, expr);
1315         }
1316       else if (!int_fits_type_p (expr, c_common_unsigned_type (type)))
1317         warning (OPT_Woverflow,
1318                  "overflow in implicit constant conversion");
1319       /* No warning for converting 0x80000000 to int.  */
1320       else if (pedantic
1321                && (TREE_CODE (TREE_TYPE (expr)) != INTEGER_TYPE
1322                    || TYPE_PRECISION (TREE_TYPE (expr))
1323                    != TYPE_PRECISION (type)))
1324         warning (OPT_Woverflow,
1325                  "overflow in implicit constant conversion");
1326
1327       else if (warn_conversion)
1328         conversion_warning (type, expr);
1329     }
1330   else if (TREE_CODE (result) == INTEGER_CST && TREE_OVERFLOW (result))
1331     warning (OPT_Woverflow,
1332              "overflow in implicit constant conversion");
1333   else if (warn_conversion)
1334     conversion_warning (type, expr);
1335
1336   return result;
1337 }
1338 \f
1339 /* A node in a list that describes references to variables (EXPR), which are
1340    either read accesses if WRITER is zero, or write accesses, in which case
1341    WRITER is the parent of EXPR.  */
1342 struct tlist
1343 {
1344   struct tlist *next;
1345   tree expr, writer;
1346 };
1347
1348 /* Used to implement a cache the results of a call to verify_tree.  We only
1349    use this for SAVE_EXPRs.  */
1350 struct tlist_cache
1351 {
1352   struct tlist_cache *next;
1353   struct tlist *cache_before_sp;
1354   struct tlist *cache_after_sp;
1355   tree expr;
1356 };
1357
1358 /* Obstack to use when allocating tlist structures, and corresponding
1359    firstobj.  */
1360 static struct obstack tlist_obstack;
1361 static char *tlist_firstobj = 0;
1362
1363 /* Keep track of the identifiers we've warned about, so we can avoid duplicate
1364    warnings.  */
1365 static struct tlist *warned_ids;
1366 /* SAVE_EXPRs need special treatment.  We process them only once and then
1367    cache the results.  */
1368 static struct tlist_cache *save_expr_cache;
1369
1370 static void add_tlist (struct tlist **, struct tlist *, tree, int);
1371 static void merge_tlist (struct tlist **, struct tlist *, int);
1372 static void verify_tree (tree, struct tlist **, struct tlist **, tree);
1373 static int warning_candidate_p (tree);
1374 static void warn_for_collisions (struct tlist *);
1375 static void warn_for_collisions_1 (tree, tree, struct tlist *, int);
1376 static struct tlist *new_tlist (struct tlist *, tree, tree);
1377
1378 /* Create a new struct tlist and fill in its fields.  */
1379 static struct tlist *
1380 new_tlist (struct tlist *next, tree t, tree writer)
1381 {
1382   struct tlist *l;
1383   l = XOBNEW (&tlist_obstack, struct tlist);
1384   l->next = next;
1385   l->expr = t;
1386   l->writer = writer;
1387   return l;
1388 }
1389
1390 /* Add duplicates of the nodes found in ADD to the list *TO.  If EXCLUDE_WRITER
1391    is nonnull, we ignore any node we find which has a writer equal to it.  */
1392
1393 static void
1394 add_tlist (struct tlist **to, struct tlist *add, tree exclude_writer, int copy)
1395 {
1396   while (add)
1397     {
1398       struct tlist *next = add->next;
1399       if (!copy)
1400         add->next = *to;
1401       if (!exclude_writer || add->writer != exclude_writer)
1402         *to = copy ? new_tlist (*to, add->expr, add->writer) : add;
1403       add = next;
1404     }
1405 }
1406
1407 /* Merge the nodes of ADD into TO.  This merging process is done so that for
1408    each variable that already exists in TO, no new node is added; however if
1409    there is a write access recorded in ADD, and an occurrence on TO is only
1410    a read access, then the occurrence in TO will be modified to record the
1411    write.  */
1412
1413 static void
1414 merge_tlist (struct tlist **to, struct tlist *add, int copy)
1415 {
1416   struct tlist **end = to;
1417
1418   while (*end)
1419     end = &(*end)->next;
1420
1421   while (add)
1422     {
1423       int found = 0;
1424       struct tlist *tmp2;
1425       struct tlist *next = add->next;
1426
1427       for (tmp2 = *to; tmp2; tmp2 = tmp2->next)
1428         if (tmp2->expr == add->expr)
1429           {
1430             found = 1;
1431             if (!tmp2->writer)
1432               tmp2->writer = add->writer;
1433           }
1434       if (!found)
1435         {
1436           *end = copy ? add : new_tlist (NULL, add->expr, add->writer);
1437           end = &(*end)->next;
1438           *end = 0;
1439         }
1440       add = next;
1441     }
1442 }
1443
1444 /* WRITTEN is a variable, WRITER is its parent.  Warn if any of the variable
1445    references in list LIST conflict with it, excluding reads if ONLY writers
1446    is nonzero.  */
1447
1448 static void
1449 warn_for_collisions_1 (tree written, tree writer, struct tlist *list,
1450                        int only_writes)
1451 {
1452   struct tlist *tmp;
1453
1454   /* Avoid duplicate warnings.  */
1455   for (tmp = warned_ids; tmp; tmp = tmp->next)
1456     if (tmp->expr == written)
1457       return;
1458
1459   while (list)
1460     {
1461       if (list->expr == written
1462           && list->writer != writer
1463           && (!only_writes || list->writer)
1464           && DECL_NAME (list->expr))
1465         {
1466           warned_ids = new_tlist (warned_ids, written, NULL_TREE);
1467           warning (0, "operation on %qE may be undefined", list->expr);
1468         }
1469       list = list->next;
1470     }
1471 }
1472
1473 /* Given a list LIST of references to variables, find whether any of these
1474    can cause conflicts due to missing sequence points.  */
1475
1476 static void
1477 warn_for_collisions (struct tlist *list)
1478 {
1479   struct tlist *tmp;
1480
1481   for (tmp = list; tmp; tmp = tmp->next)
1482     {
1483       if (tmp->writer)
1484         warn_for_collisions_1 (tmp->expr, tmp->writer, list, 0);
1485     }
1486 }
1487
1488 /* Return nonzero if X is a tree that can be verified by the sequence point
1489    warnings.  */
1490 static int
1491 warning_candidate_p (tree x)
1492 {
1493   return TREE_CODE (x) == VAR_DECL || TREE_CODE (x) == PARM_DECL;
1494 }
1495
1496 /* Walk the tree X, and record accesses to variables.  If X is written by the
1497    parent tree, WRITER is the parent.
1498    We store accesses in one of the two lists: PBEFORE_SP, and PNO_SP.  If this
1499    expression or its only operand forces a sequence point, then everything up
1500    to the sequence point is stored in PBEFORE_SP.  Everything else gets stored
1501    in PNO_SP.
1502    Once we return, we will have emitted warnings if any subexpression before
1503    such a sequence point could be undefined.  On a higher level, however, the
1504    sequence point may not be relevant, and we'll merge the two lists.
1505
1506    Example: (b++, a) + b;
1507    The call that processes the COMPOUND_EXPR will store the increment of B
1508    in PBEFORE_SP, and the use of A in PNO_SP.  The higher-level call that
1509    processes the PLUS_EXPR will need to merge the two lists so that
1510    eventually, all accesses end up on the same list (and we'll warn about the
1511    unordered subexpressions b++ and b.
1512
1513    A note on merging.  If we modify the former example so that our expression
1514    becomes
1515      (b++, b) + a
1516    care must be taken not simply to add all three expressions into the final
1517    PNO_SP list.  The function merge_tlist takes care of that by merging the
1518    before-SP list of the COMPOUND_EXPR into its after-SP list in a special
1519    way, so that no more than one access to B is recorded.  */
1520
1521 static void
1522 verify_tree (tree x, struct tlist **pbefore_sp, struct tlist **pno_sp,
1523              tree writer)
1524 {
1525   struct tlist *tmp_before, *tmp_nosp, *tmp_list2, *tmp_list3;
1526   enum tree_code code;
1527   enum tree_code_class cl;
1528
1529   /* X may be NULL if it is the operand of an empty statement expression
1530      ({ }).  */
1531   if (x == NULL)
1532     return;
1533
1534  restart:
1535   code = TREE_CODE (x);
1536   cl = TREE_CODE_CLASS (code);
1537
1538   if (warning_candidate_p (x))
1539     {
1540       *pno_sp = new_tlist (*pno_sp, x, writer);
1541       return;
1542     }
1543
1544   switch (code)
1545     {
1546     case CONSTRUCTOR:
1547       return;
1548
1549     case COMPOUND_EXPR:
1550     case TRUTH_ANDIF_EXPR:
1551     case TRUTH_ORIF_EXPR:
1552       tmp_before = tmp_nosp = tmp_list3 = 0;
1553       verify_tree (TREE_OPERAND (x, 0), &tmp_before, &tmp_nosp, NULL_TREE);
1554       warn_for_collisions (tmp_nosp);
1555       merge_tlist (pbefore_sp, tmp_before, 0);
1556       merge_tlist (pbefore_sp, tmp_nosp, 0);
1557       verify_tree (TREE_OPERAND (x, 1), &tmp_list3, pno_sp, NULL_TREE);
1558       merge_tlist (pbefore_sp, tmp_list3, 0);
1559       return;
1560
1561     case COND_EXPR:
1562       tmp_before = tmp_list2 = 0;
1563       verify_tree (TREE_OPERAND (x, 0), &tmp_before, &tmp_list2, NULL_TREE);
1564       warn_for_collisions (tmp_list2);
1565       merge_tlist (pbefore_sp, tmp_before, 0);
1566       merge_tlist (pbefore_sp, tmp_list2, 1);
1567
1568       tmp_list3 = tmp_nosp = 0;
1569       verify_tree (TREE_OPERAND (x, 1), &tmp_list3, &tmp_nosp, NULL_TREE);
1570       warn_for_collisions (tmp_nosp);
1571       merge_tlist (pbefore_sp, tmp_list3, 0);
1572
1573       tmp_list3 = tmp_list2 = 0;
1574       verify_tree (TREE_OPERAND (x, 2), &tmp_list3, &tmp_list2, NULL_TREE);
1575       warn_for_collisions (tmp_list2);
1576       merge_tlist (pbefore_sp, tmp_list3, 0);
1577       /* Rather than add both tmp_nosp and tmp_list2, we have to merge the
1578          two first, to avoid warning for (a ? b++ : b++).  */
1579       merge_tlist (&tmp_nosp, tmp_list2, 0);
1580       add_tlist (pno_sp, tmp_nosp, NULL_TREE, 0);
1581       return;
1582
1583     case PREDECREMENT_EXPR:
1584     case PREINCREMENT_EXPR:
1585     case POSTDECREMENT_EXPR:
1586     case POSTINCREMENT_EXPR:
1587       verify_tree (TREE_OPERAND (x, 0), pno_sp, pno_sp, x);
1588       return;
1589
1590     case MODIFY_EXPR:
1591       tmp_before = tmp_nosp = tmp_list3 = 0;
1592       verify_tree (TREE_OPERAND (x, 1), &tmp_before, &tmp_nosp, NULL_TREE);
1593       verify_tree (TREE_OPERAND (x, 0), &tmp_list3, &tmp_list3, x);
1594       /* Expressions inside the LHS are not ordered wrt. the sequence points
1595          in the RHS.  Example:
1596            *a = (a++, 2)
1597          Despite the fact that the modification of "a" is in the before_sp
1598          list (tmp_before), it conflicts with the use of "a" in the LHS.
1599          We can handle this by adding the contents of tmp_list3
1600          to those of tmp_before, and redoing the collision warnings for that
1601          list.  */
1602       add_tlist (&tmp_before, tmp_list3, x, 1);
1603       warn_for_collisions (tmp_before);
1604       /* Exclude the LHS itself here; we first have to merge it into the
1605          tmp_nosp list.  This is done to avoid warning for "a = a"; if we
1606          didn't exclude the LHS, we'd get it twice, once as a read and once
1607          as a write.  */
1608       add_tlist (pno_sp, tmp_list3, x, 0);
1609       warn_for_collisions_1 (TREE_OPERAND (x, 0), x, tmp_nosp, 1);
1610
1611       merge_tlist (pbefore_sp, tmp_before, 0);
1612       if (warning_candidate_p (TREE_OPERAND (x, 0)))
1613         merge_tlist (&tmp_nosp, new_tlist (NULL, TREE_OPERAND (x, 0), x), 0);
1614       add_tlist (pno_sp, tmp_nosp, NULL_TREE, 1);
1615       return;
1616
1617     case CALL_EXPR:
1618       /* We need to warn about conflicts among arguments and conflicts between
1619          args and the function address.  Side effects of the function address,
1620          however, are not ordered by the sequence point of the call.  */
1621       {
1622         call_expr_arg_iterator iter;
1623         tree arg;
1624         tmp_before = tmp_nosp = 0;
1625         verify_tree (CALL_EXPR_FN (x), &tmp_before, &tmp_nosp, NULL_TREE);
1626         FOR_EACH_CALL_EXPR_ARG (arg, iter, x)
1627           {
1628             tmp_list2 = tmp_list3 = 0;
1629             verify_tree (arg, &tmp_list2, &tmp_list3, NULL_TREE);
1630             merge_tlist (&tmp_list3, tmp_list2, 0);
1631             add_tlist (&tmp_before, tmp_list3, NULL_TREE, 0);
1632           }
1633         add_tlist (&tmp_before, tmp_nosp, NULL_TREE, 0);
1634         warn_for_collisions (tmp_before);
1635         add_tlist (pbefore_sp, tmp_before, NULL_TREE, 0);
1636         return;
1637       }
1638
1639     case TREE_LIST:
1640       /* Scan all the list, e.g. indices of multi dimensional array.  */
1641       while (x)
1642         {
1643           tmp_before = tmp_nosp = 0;
1644           verify_tree (TREE_VALUE (x), &tmp_before, &tmp_nosp, NULL_TREE);
1645           merge_tlist (&tmp_nosp, tmp_before, 0);
1646           add_tlist (pno_sp, tmp_nosp, NULL_TREE, 0);
1647           x = TREE_CHAIN (x);
1648         }
1649       return;
1650
1651     case SAVE_EXPR:
1652       {
1653         struct tlist_cache *t;
1654         for (t = save_expr_cache; t; t = t->next)
1655           if (t->expr == x)
1656             break;
1657
1658         if (!t)
1659           {
1660             t = XOBNEW (&tlist_obstack, struct tlist_cache);
1661             t->next = save_expr_cache;
1662             t->expr = x;
1663             save_expr_cache = t;
1664
1665             tmp_before = tmp_nosp = 0;
1666             verify_tree (TREE_OPERAND (x, 0), &tmp_before, &tmp_nosp, NULL_TREE);
1667             warn_for_collisions (tmp_nosp);
1668
1669             tmp_list3 = 0;
1670             while (tmp_nosp)
1671               {
1672                 struct tlist *t = tmp_nosp;
1673                 tmp_nosp = t->next;
1674                 merge_tlist (&tmp_list3, t, 0);
1675               }
1676             t->cache_before_sp = tmp_before;
1677             t->cache_after_sp = tmp_list3;
1678           }
1679         merge_tlist (pbefore_sp, t->cache_before_sp, 1);
1680         add_tlist (pno_sp, t->cache_after_sp, NULL_TREE, 1);
1681         return;
1682       }
1683
1684     default:
1685       /* For other expressions, simply recurse on their operands.
1686          Manual tail recursion for unary expressions.
1687          Other non-expressions need not be processed.  */
1688       if (cl == tcc_unary)
1689         {
1690           x = TREE_OPERAND (x, 0);
1691           writer = 0;
1692           goto restart;
1693         }
1694       else if (IS_EXPR_CODE_CLASS (cl))
1695         {
1696           int lp;
1697           int max = TREE_OPERAND_LENGTH (x);
1698           for (lp = 0; lp < max; lp++)
1699             {
1700               tmp_before = tmp_nosp = 0;
1701               verify_tree (TREE_OPERAND (x, lp), &tmp_before, &tmp_nosp, 0);
1702               merge_tlist (&tmp_nosp, tmp_before, 0);
1703               add_tlist (pno_sp, tmp_nosp, NULL_TREE, 0);
1704             }
1705         }
1706       return;
1707     }
1708 }
1709
1710 /* Try to warn for undefined behavior in EXPR due to missing sequence
1711    points.  */
1712
1713 void
1714 verify_sequence_points (tree expr)
1715 {
1716   struct tlist *before_sp = 0, *after_sp = 0;
1717
1718   warned_ids = 0;
1719   save_expr_cache = 0;
1720   if (tlist_firstobj == 0)
1721     {
1722       gcc_obstack_init (&tlist_obstack);
1723       tlist_firstobj = (char *) obstack_alloc (&tlist_obstack, 0);
1724     }
1725
1726   verify_tree (expr, &before_sp, &after_sp, 0);
1727   warn_for_collisions (after_sp);
1728   obstack_free (&tlist_obstack, tlist_firstobj);
1729 }
1730 \f
1731 /* Validate the expression after `case' and apply default promotions.  */
1732
1733 static tree
1734 check_case_value (tree value)
1735 {
1736   if (value == NULL_TREE)
1737     return value;
1738
1739   /* ??? Can we ever get nops here for a valid case value?  We
1740      shouldn't for C.  */
1741   STRIP_TYPE_NOPS (value);
1742   /* In C++, the following is allowed:
1743
1744        const int i = 3;
1745        switch (...) { case i: ... }
1746
1747      So, we try to reduce the VALUE to a constant that way.  */
1748   if (c_dialect_cxx ())
1749     {
1750       value = decl_constant_value (value);
1751       STRIP_TYPE_NOPS (value);
1752       value = fold (value);
1753     }
1754
1755   if (TREE_CODE (value) == INTEGER_CST)
1756     /* Promote char or short to int.  */
1757     value = perform_integral_promotions (value);
1758   else if (value != error_mark_node)
1759     {
1760       error ("case label does not reduce to an integer constant");
1761       value = error_mark_node;
1762     }
1763
1764   constant_expression_warning (value);
1765
1766   return value;
1767 }
1768 \f
1769 /* See if the case values LOW and HIGH are in the range of the original
1770    type (i.e. before the default conversion to int) of the switch testing
1771    expression.
1772    TYPE is the promoted type of the testing expression, and ORIG_TYPE is
1773    the type before promoting it.  CASE_LOW_P is a pointer to the lower
1774    bound of the case label, and CASE_HIGH_P is the upper bound or NULL
1775    if the case is not a case range.
1776    The caller has to make sure that we are not called with NULL for
1777    CASE_LOW_P (i.e. the default case).
1778    Returns true if the case label is in range of ORIG_TYPE (saturated or
1779    untouched) or false if the label is out of range.  */
1780
1781 static bool
1782 check_case_bounds (tree type, tree orig_type,
1783                    tree *case_low_p, tree *case_high_p)
1784 {
1785   tree min_value, max_value;
1786   tree case_low = *case_low_p;
1787   tree case_high = case_high_p ? *case_high_p : case_low;
1788
1789   /* If there was a problem with the original type, do nothing.  */
1790   if (orig_type == error_mark_node)
1791     return true;
1792
1793   min_value = TYPE_MIN_VALUE (orig_type);
1794   max_value = TYPE_MAX_VALUE (orig_type);
1795
1796   /* Case label is less than minimum for type.  */
1797   if (tree_int_cst_compare (case_low, min_value) < 0
1798       && tree_int_cst_compare (case_high, min_value) < 0)
1799     {
1800       warning (0, "case label value is less than minimum value for type");
1801       return false;
1802     }
1803
1804   /* Case value is greater than maximum for type.  */
1805   if (tree_int_cst_compare (case_low, max_value) > 0
1806       && tree_int_cst_compare (case_high, max_value) > 0)
1807     {
1808       warning (0, "case label value exceeds maximum value for type");
1809       return false;
1810     }
1811
1812   /* Saturate lower case label value to minimum.  */
1813   if (tree_int_cst_compare (case_high, min_value) >= 0
1814       && tree_int_cst_compare (case_low, min_value) < 0)
1815     {
1816       warning (0, "lower value in case label range"
1817                " less than minimum value for type");
1818       case_low = min_value;
1819     }
1820
1821   /* Saturate upper case label value to maximum.  */
1822   if (tree_int_cst_compare (case_low, max_value) <= 0
1823       && tree_int_cst_compare (case_high, max_value) > 0)
1824     {
1825       warning (0, "upper value in case label range"
1826                " exceeds maximum value for type");
1827       case_high = max_value;
1828     }
1829
1830   if (*case_low_p != case_low)
1831     *case_low_p = convert (type, case_low);
1832   if (case_high_p && *case_high_p != case_high)
1833     *case_high_p = convert (type, case_high);
1834
1835   return true;
1836 }
1837 \f
1838 /* Return an integer type with BITS bits of precision,
1839    that is unsigned if UNSIGNEDP is nonzero, otherwise signed.  */
1840
1841 tree
1842 c_common_type_for_size (unsigned int bits, int unsignedp)
1843 {
1844   if (bits == TYPE_PRECISION (integer_type_node))
1845     return unsignedp ? unsigned_type_node : integer_type_node;
1846
1847   if (bits == TYPE_PRECISION (signed_char_type_node))
1848     return unsignedp ? unsigned_char_type_node : signed_char_type_node;
1849
1850   if (bits == TYPE_PRECISION (short_integer_type_node))
1851     return unsignedp ? short_unsigned_type_node : short_integer_type_node;
1852
1853   if (bits == TYPE_PRECISION (long_integer_type_node))
1854     return unsignedp ? long_unsigned_type_node : long_integer_type_node;
1855
1856   if (bits == TYPE_PRECISION (long_long_integer_type_node))
1857     return (unsignedp ? long_long_unsigned_type_node
1858             : long_long_integer_type_node);
1859
1860   if (bits == TYPE_PRECISION (widest_integer_literal_type_node))
1861     return (unsignedp ? widest_unsigned_literal_type_node
1862             : widest_integer_literal_type_node);
1863
1864   if (bits <= TYPE_PRECISION (intQI_type_node))
1865     return unsignedp ? unsigned_intQI_type_node : intQI_type_node;
1866
1867   if (bits <= TYPE_PRECISION (intHI_type_node))
1868     return unsignedp ? unsigned_intHI_type_node : intHI_type_node;
1869
1870   if (bits <= TYPE_PRECISION (intSI_type_node))
1871     return unsignedp ? unsigned_intSI_type_node : intSI_type_node;
1872
1873   if (bits <= TYPE_PRECISION (intDI_type_node))
1874     return unsignedp ? unsigned_intDI_type_node : intDI_type_node;
1875
1876   return 0;
1877 }
1878
1879 /* Used for communication between c_common_type_for_mode and
1880    c_register_builtin_type.  */
1881 static GTY(()) tree registered_builtin_types;
1882
1883 /* Return a data type that has machine mode MODE.
1884    If the mode is an integer,
1885    then UNSIGNEDP selects between signed and unsigned types.  */
1886
1887 tree
1888 c_common_type_for_mode (enum machine_mode mode, int unsignedp)
1889 {
1890   tree t;
1891
1892   if (mode == TYPE_MODE (integer_type_node))
1893     return unsignedp ? unsigned_type_node : integer_type_node;
1894
1895   if (mode == TYPE_MODE (signed_char_type_node))
1896     return unsignedp ? unsigned_char_type_node : signed_char_type_node;
1897
1898   if (mode == TYPE_MODE (short_integer_type_node))
1899     return unsignedp ? short_unsigned_type_node : short_integer_type_node;
1900
1901   if (mode == TYPE_MODE (long_integer_type_node))
1902     return unsignedp ? long_unsigned_type_node : long_integer_type_node;
1903
1904   if (mode == TYPE_MODE (long_long_integer_type_node))
1905     return unsignedp ? long_long_unsigned_type_node : long_long_integer_type_node;
1906
1907   if (mode == TYPE_MODE (widest_integer_literal_type_node))
1908     return unsignedp ? widest_unsigned_literal_type_node
1909                      : widest_integer_literal_type_node;
1910
1911   if (mode == QImode)
1912     return unsignedp ? unsigned_intQI_type_node : intQI_type_node;
1913
1914   if (mode == HImode)
1915     return unsignedp ? unsigned_intHI_type_node : intHI_type_node;
1916
1917   if (mode == SImode)
1918     return unsignedp ? unsigned_intSI_type_node : intSI_type_node;
1919
1920   if (mode == DImode)
1921     return unsignedp ? unsigned_intDI_type_node : intDI_type_node;
1922
1923 #if HOST_BITS_PER_WIDE_INT >= 64
1924   if (mode == TYPE_MODE (intTI_type_node))
1925     return unsignedp ? unsigned_intTI_type_node : intTI_type_node;
1926 #endif
1927
1928   if (mode == TYPE_MODE (float_type_node))
1929     return float_type_node;
1930
1931   if (mode == TYPE_MODE (double_type_node))
1932     return double_type_node;
1933
1934   if (mode == TYPE_MODE (long_double_type_node))
1935     return long_double_type_node;
1936
1937   if (mode == TYPE_MODE (void_type_node))
1938     return void_type_node;
1939
1940   if (mode == TYPE_MODE (build_pointer_type (char_type_node)))
1941     return (unsignedp
1942             ? make_unsigned_type (GET_MODE_PRECISION (mode))
1943             : make_signed_type (GET_MODE_PRECISION (mode)));
1944
1945   if (mode == TYPE_MODE (build_pointer_type (integer_type_node)))
1946     return (unsignedp
1947             ? make_unsigned_type (GET_MODE_PRECISION (mode))
1948             : make_signed_type (GET_MODE_PRECISION (mode)));
1949
1950   if (COMPLEX_MODE_P (mode))
1951     {
1952       enum machine_mode inner_mode;
1953       tree inner_type;
1954
1955       if (mode == TYPE_MODE (complex_float_type_node))
1956         return complex_float_type_node;
1957       if (mode == TYPE_MODE (complex_double_type_node))
1958         return complex_double_type_node;
1959       if (mode == TYPE_MODE (complex_long_double_type_node))
1960         return complex_long_double_type_node;
1961
1962       if (mode == TYPE_MODE (complex_integer_type_node) && !unsignedp)
1963         return complex_integer_type_node;
1964
1965       inner_mode = GET_MODE_INNER (mode);
1966       inner_type = c_common_type_for_mode (inner_mode, unsignedp);
1967       if (inner_type != NULL_TREE)
1968         return build_complex_type (inner_type);
1969     }
1970   else if (VECTOR_MODE_P (mode))
1971     {
1972       enum machine_mode inner_mode = GET_MODE_INNER (mode);
1973       tree inner_type = c_common_type_for_mode (inner_mode, unsignedp);
1974       if (inner_type != NULL_TREE)
1975         return build_vector_type_for_mode (inner_type, mode);
1976     }
1977
1978   if (mode == TYPE_MODE (dfloat32_type_node))
1979     return dfloat32_type_node;
1980   if (mode == TYPE_MODE (dfloat64_type_node))
1981     return dfloat64_type_node;
1982   if (mode == TYPE_MODE (dfloat128_type_node))
1983     return dfloat128_type_node;
1984
1985   for (t = registered_builtin_types; t; t = TREE_CHAIN (t))
1986     if (TYPE_MODE (TREE_VALUE (t)) == mode)
1987       return TREE_VALUE (t);
1988
1989   return 0;
1990 }
1991
1992 /* Return an unsigned type the same as TYPE in other respects.  */
1993 tree
1994 c_common_unsigned_type (tree type)
1995 {
1996   tree type1 = TYPE_MAIN_VARIANT (type);
1997   if (type1 == signed_char_type_node || type1 == char_type_node)
1998     return unsigned_char_type_node;
1999   if (type1 == integer_type_node)
2000     return unsigned_type_node;
2001   if (type1 == short_integer_type_node)
2002     return short_unsigned_type_node;
2003   if (type1 == long_integer_type_node)
2004     return long_unsigned_type_node;
2005   if (type1 == long_long_integer_type_node)
2006     return long_long_unsigned_type_node;
2007   if (type1 == widest_integer_literal_type_node)
2008     return widest_unsigned_literal_type_node;
2009 #if HOST_BITS_PER_WIDE_INT >= 64
2010   if (type1 == intTI_type_node)
2011     return unsigned_intTI_type_node;
2012 #endif
2013   if (type1 == intDI_type_node)
2014     return unsigned_intDI_type_node;
2015   if (type1 == intSI_type_node)
2016     return unsigned_intSI_type_node;
2017   if (type1 == intHI_type_node)
2018     return unsigned_intHI_type_node;
2019   if (type1 == intQI_type_node)
2020     return unsigned_intQI_type_node;
2021
2022   return c_common_signed_or_unsigned_type (1, type);
2023 }
2024
2025 /* Return a signed type the same as TYPE in other respects.  */
2026
2027 tree
2028 c_common_signed_type (tree type)
2029 {
2030   tree type1 = TYPE_MAIN_VARIANT (type);
2031   if (type1 == unsigned_char_type_node || type1 == char_type_node)
2032     return signed_char_type_node;
2033   if (type1 == unsigned_type_node)
2034     return integer_type_node;
2035   if (type1 == short_unsigned_type_node)
2036     return short_integer_type_node;
2037   if (type1 == long_unsigned_type_node)
2038     return long_integer_type_node;
2039   if (type1 == long_long_unsigned_type_node)
2040     return long_long_integer_type_node;
2041   if (type1 == widest_unsigned_literal_type_node)
2042     return widest_integer_literal_type_node;
2043 #if HOST_BITS_PER_WIDE_INT >= 64
2044   if (type1 == unsigned_intTI_type_node)
2045     return intTI_type_node;
2046 #endif
2047   if (type1 == unsigned_intDI_type_node)
2048     return intDI_type_node;
2049   if (type1 == unsigned_intSI_type_node)
2050     return intSI_type_node;
2051   if (type1 == unsigned_intHI_type_node)
2052     return intHI_type_node;
2053   if (type1 == unsigned_intQI_type_node)
2054     return intQI_type_node;
2055
2056   return c_common_signed_or_unsigned_type (0, type);
2057 }
2058
2059 /* Return a type the same as TYPE except unsigned or
2060    signed according to UNSIGNEDP.  */
2061
2062 tree
2063 c_common_signed_or_unsigned_type (int unsignedp, tree type)
2064 {
2065   if (!INTEGRAL_TYPE_P (type)
2066       || TYPE_UNSIGNED (type) == unsignedp)
2067     return type;
2068
2069   /* For ENUMERAL_TYPEs in C++, must check the mode of the types, not
2070      the precision; they have precision set to match their range, but
2071      may use a wider mode to match an ABI.  If we change modes, we may
2072      wind up with bad conversions.  For INTEGER_TYPEs in C, must check
2073      the precision as well, so as to yield correct results for
2074      bit-field types.  C++ does not have these separate bit-field
2075      types, and producing a signed or unsigned variant of an
2076      ENUMERAL_TYPE may cause other problems as well.  */
2077
2078 #define TYPE_OK(node)                                                       \
2079   (TYPE_MODE (type) == TYPE_MODE (node)                                     \
2080    && (c_dialect_cxx () || TYPE_PRECISION (type) == TYPE_PRECISION (node)))
2081   if (TYPE_OK (signed_char_type_node))
2082     return unsignedp ? unsigned_char_type_node : signed_char_type_node;
2083   if (TYPE_OK (integer_type_node))
2084     return unsignedp ? unsigned_type_node : integer_type_node;
2085   if (TYPE_OK (short_integer_type_node))
2086     return unsignedp ? short_unsigned_type_node : short_integer_type_node;
2087   if (TYPE_OK (long_integer_type_node))
2088     return unsignedp ? long_unsigned_type_node : long_integer_type_node;
2089   if (TYPE_OK (long_long_integer_type_node))
2090     return (unsignedp ? long_long_unsigned_type_node
2091             : long_long_integer_type_node);
2092   if (TYPE_OK (widest_integer_literal_type_node))
2093     return (unsignedp ? widest_unsigned_literal_type_node
2094             : widest_integer_literal_type_node);
2095
2096 #if HOST_BITS_PER_WIDE_INT >= 64
2097   if (TYPE_OK (intTI_type_node))
2098     return unsignedp ? unsigned_intTI_type_node : intTI_type_node;
2099 #endif
2100   if (TYPE_OK (intDI_type_node))
2101     return unsignedp ? unsigned_intDI_type_node : intDI_type_node;
2102   if (TYPE_OK (intSI_type_node))
2103     return unsignedp ? unsigned_intSI_type_node : intSI_type_node;
2104   if (TYPE_OK (intHI_type_node))
2105     return unsignedp ? unsigned_intHI_type_node : intHI_type_node;
2106   if (TYPE_OK (intQI_type_node))
2107     return unsignedp ? unsigned_intQI_type_node : intQI_type_node;
2108 #undef TYPE_OK
2109
2110   if (c_dialect_cxx ())
2111     return type;
2112   else
2113     return build_nonstandard_integer_type (TYPE_PRECISION (type), unsignedp);
2114 }
2115
2116 /* Build a bit-field integer type for the given WIDTH and UNSIGNEDP.  */
2117
2118 tree
2119 c_build_bitfield_integer_type (unsigned HOST_WIDE_INT width, int unsignedp)
2120 {
2121   /* Extended integer types of the same width as a standard type have
2122      lesser rank, so those of the same width as int promote to int or
2123      unsigned int and are valid for printf formats expecting int or
2124      unsigned int.  To avoid such special cases, avoid creating
2125      extended integer types for bit-fields if a standard integer type
2126      is available.  */
2127   if (width == TYPE_PRECISION (integer_type_node))
2128     return unsignedp ? unsigned_type_node : integer_type_node;
2129   if (width == TYPE_PRECISION (signed_char_type_node))
2130     return unsignedp ? unsigned_char_type_node : signed_char_type_node;
2131   if (width == TYPE_PRECISION (short_integer_type_node))
2132     return unsignedp ? short_unsigned_type_node : short_integer_type_node;
2133   if (width == TYPE_PRECISION (long_integer_type_node))
2134     return unsignedp ? long_unsigned_type_node : long_integer_type_node;
2135   if (width == TYPE_PRECISION (long_long_integer_type_node))
2136     return (unsignedp ? long_long_unsigned_type_node
2137             : long_long_integer_type_node);
2138   return build_nonstandard_integer_type (width, unsignedp);
2139 }
2140
2141 /* The C version of the register_builtin_type langhook.  */
2142
2143 void
2144 c_register_builtin_type (tree type, const char* name)
2145 {
2146   tree decl;
2147
2148   decl = build_decl (TYPE_DECL, get_identifier (name), type);
2149   DECL_ARTIFICIAL (decl) = 1;
2150   if (!TYPE_NAME (type))
2151     TYPE_NAME (type) = decl;
2152   pushdecl (decl);
2153
2154   registered_builtin_types = tree_cons (0, type, registered_builtin_types);
2155 }
2156
2157 \f
2158 /* Return the minimum number of bits needed to represent VALUE in a
2159    signed or unsigned type, UNSIGNEDP says which.  */
2160
2161 unsigned int
2162 min_precision (tree value, int unsignedp)
2163 {
2164   int log;
2165
2166   /* If the value is negative, compute its negative minus 1.  The latter
2167      adjustment is because the absolute value of the largest negative value
2168      is one larger than the largest positive value.  This is equivalent to
2169      a bit-wise negation, so use that operation instead.  */
2170
2171   if (tree_int_cst_sgn (value) < 0)
2172     value = fold_build1 (BIT_NOT_EXPR, TREE_TYPE (value), value);
2173
2174   /* Return the number of bits needed, taking into account the fact
2175      that we need one more bit for a signed than unsigned type.  */
2176
2177   if (integer_zerop (value))
2178     log = 0;
2179   else
2180     log = tree_floor_log2 (value);
2181
2182   return log + 1 + !unsignedp;
2183 }
2184 \f
2185 /* Print an error message for invalid operands to arith operation
2186    CODE.  */
2187
2188 void
2189 binary_op_error (enum tree_code code)
2190 {
2191   const char *opname;
2192
2193   switch (code)
2194     {
2195     case PLUS_EXPR:
2196       opname = "+"; break;
2197     case MINUS_EXPR:
2198       opname = "-"; break;
2199     case MULT_EXPR:
2200       opname = "*"; break;
2201     case MAX_EXPR:
2202       opname = "max"; break;
2203     case MIN_EXPR:
2204       opname = "min"; break;
2205     case EQ_EXPR:
2206       opname = "=="; break;
2207     case NE_EXPR:
2208       opname = "!="; break;
2209     case LE_EXPR:
2210       opname = "<="; break;
2211     case GE_EXPR:
2212       opname = ">="; break;
2213     case LT_EXPR:
2214       opname = "<"; break;
2215     case GT_EXPR:
2216       opname = ">"; break;
2217     case LSHIFT_EXPR:
2218       opname = "<<"; break;
2219     case RSHIFT_EXPR:
2220       opname = ">>"; break;
2221     case TRUNC_MOD_EXPR:
2222     case FLOOR_MOD_EXPR:
2223       opname = "%"; break;
2224     case TRUNC_DIV_EXPR:
2225     case FLOOR_DIV_EXPR:
2226       opname = "/"; break;
2227     case BIT_AND_EXPR:
2228       opname = "&"; break;
2229     case BIT_IOR_EXPR:
2230       opname = "|"; break;
2231     case TRUTH_ANDIF_EXPR:
2232       opname = "&&"; break;
2233     case TRUTH_ORIF_EXPR:
2234       opname = "||"; break;
2235     case BIT_XOR_EXPR:
2236       opname = "^"; break;
2237     default:
2238       gcc_unreachable ();
2239     }
2240   error ("invalid operands to binary %s", opname);
2241 }
2242 \f
2243 /* Subroutine of build_binary_op, used for comparison operations.
2244    See if the operands have both been converted from subword integer types
2245    and, if so, perhaps change them both back to their original type.
2246    This function is also responsible for converting the two operands
2247    to the proper common type for comparison.
2248
2249    The arguments of this function are all pointers to local variables
2250    of build_binary_op: OP0_PTR is &OP0, OP1_PTR is &OP1,
2251    RESTYPE_PTR is &RESULT_TYPE and RESCODE_PTR is &RESULTCODE.
2252
2253    If this function returns nonzero, it means that the comparison has
2254    a constant value.  What this function returns is an expression for
2255    that value.  */
2256
2257 tree
2258 shorten_compare (tree *op0_ptr, tree *op1_ptr, tree *restype_ptr,
2259                  enum tree_code *rescode_ptr)
2260 {
2261   tree type;
2262   tree op0 = *op0_ptr;
2263   tree op1 = *op1_ptr;
2264   int unsignedp0, unsignedp1;
2265   int real1, real2;
2266   tree primop0, primop1;
2267   enum tree_code code = *rescode_ptr;
2268
2269   /* Throw away any conversions to wider types
2270      already present in the operands.  */
2271
2272   primop0 = get_narrower (op0, &unsignedp0);
2273   primop1 = get_narrower (op1, &unsignedp1);
2274
2275   /* Handle the case that OP0 does not *contain* a conversion
2276      but it *requires* conversion to FINAL_TYPE.  */
2277
2278   if (op0 == primop0 && TREE_TYPE (op0) != *restype_ptr)
2279     unsignedp0 = TYPE_UNSIGNED (TREE_TYPE (op0));
2280   if (op1 == primop1 && TREE_TYPE (op1) != *restype_ptr)
2281     unsignedp1 = TYPE_UNSIGNED (TREE_TYPE (op1));
2282
2283   /* If one of the operands must be floated, we cannot optimize.  */
2284   real1 = TREE_CODE (TREE_TYPE (primop0)) == REAL_TYPE;
2285   real2 = TREE_CODE (TREE_TYPE (primop1)) == REAL_TYPE;
2286
2287   /* If first arg is constant, swap the args (changing operation
2288      so value is preserved), for canonicalization.  Don't do this if
2289      the second arg is 0.  */
2290
2291   if (TREE_CONSTANT (primop0)
2292       && !integer_zerop (primop1) && !real_zerop (primop1))
2293     {
2294       tree tem = primop0;
2295       int temi = unsignedp0;
2296       primop0 = primop1;
2297       primop1 = tem;
2298       tem = op0;
2299       op0 = op1;
2300       op1 = tem;
2301       *op0_ptr = op0;
2302       *op1_ptr = op1;
2303       unsignedp0 = unsignedp1;
2304       unsignedp1 = temi;
2305       temi = real1;
2306       real1 = real2;
2307       real2 = temi;
2308
2309       switch (code)
2310         {
2311         case LT_EXPR:
2312           code = GT_EXPR;
2313           break;
2314         case GT_EXPR:
2315           code = LT_EXPR;
2316           break;
2317         case LE_EXPR:
2318           code = GE_EXPR;
2319           break;
2320         case GE_EXPR:
2321           code = LE_EXPR;
2322           break;
2323         default:
2324           break;
2325         }
2326       *rescode_ptr = code;
2327     }
2328
2329   /* If comparing an integer against a constant more bits wide,
2330      maybe we can deduce a value of 1 or 0 independent of the data.
2331      Or else truncate the constant now
2332      rather than extend the variable at run time.
2333
2334      This is only interesting if the constant is the wider arg.
2335      Also, it is not safe if the constant is unsigned and the
2336      variable arg is signed, since in this case the variable
2337      would be sign-extended and then regarded as unsigned.
2338      Our technique fails in this case because the lowest/highest
2339      possible unsigned results don't follow naturally from the
2340      lowest/highest possible values of the variable operand.
2341      For just EQ_EXPR and NE_EXPR there is another technique that
2342      could be used: see if the constant can be faithfully represented
2343      in the other operand's type, by truncating it and reextending it
2344      and see if that preserves the constant's value.  */
2345
2346   if (!real1 && !real2
2347       && TREE_CODE (primop1) == INTEGER_CST
2348       && TYPE_PRECISION (TREE_TYPE (primop0)) < TYPE_PRECISION (*restype_ptr))
2349     {
2350       int min_gt, max_gt, min_lt, max_lt;
2351       tree maxval, minval;
2352       /* 1 if comparison is nominally unsigned.  */
2353       int unsignedp = TYPE_UNSIGNED (*restype_ptr);
2354       tree val;
2355
2356       type = c_common_signed_or_unsigned_type (unsignedp0,
2357                                                TREE_TYPE (primop0));
2358
2359       maxval = TYPE_MAX_VALUE (type);
2360       minval = TYPE_MIN_VALUE (type);
2361
2362       if (unsignedp && !unsignedp0)
2363         *restype_ptr = c_common_signed_type (*restype_ptr);
2364
2365       if (TREE_TYPE (primop1) != *restype_ptr)
2366         {
2367           /* Convert primop1 to target type, but do not introduce
2368              additional overflow.  We know primop1 is an int_cst.  */
2369           primop1 = force_fit_type_double (*restype_ptr,
2370                                            TREE_INT_CST_LOW (primop1),
2371                                            TREE_INT_CST_HIGH (primop1), 0,
2372                                            TREE_OVERFLOW (primop1));
2373         }
2374       if (type != *restype_ptr)
2375         {
2376           minval = convert (*restype_ptr, minval);
2377           maxval = convert (*restype_ptr, maxval);
2378         }
2379
2380       if (unsignedp && unsignedp0)
2381         {
2382           min_gt = INT_CST_LT_UNSIGNED (primop1, minval);
2383           max_gt = INT_CST_LT_UNSIGNED (primop1, maxval);
2384           min_lt = INT_CST_LT_UNSIGNED (minval, primop1);
2385           max_lt = INT_CST_LT_UNSIGNED (maxval, primop1);
2386         }
2387       else
2388         {
2389           min_gt = INT_CST_LT (primop1, minval);
2390           max_gt = INT_CST_LT (primop1, maxval);
2391           min_lt = INT_CST_LT (minval, primop1);
2392           max_lt = INT_CST_LT (maxval, primop1);
2393         }
2394
2395       val = 0;
2396       /* This used to be a switch, but Genix compiler can't handle that.  */
2397       if (code == NE_EXPR)
2398         {
2399           if (max_lt || min_gt)
2400             val = truthvalue_true_node;
2401         }
2402       else if (code == EQ_EXPR)
2403         {
2404           if (max_lt || min_gt)
2405             val = truthvalue_false_node;
2406         }
2407       else if (code == LT_EXPR)
2408         {
2409           if (max_lt)
2410             val = truthvalue_true_node;
2411           if (!min_lt)
2412             val = truthvalue_false_node;
2413         }
2414       else if (code == GT_EXPR)
2415         {
2416           if (min_gt)
2417             val = truthvalue_true_node;
2418           if (!max_gt)
2419             val = truthvalue_false_node;
2420         }
2421       else if (code == LE_EXPR)
2422         {
2423           if (!max_gt)
2424             val = truthvalue_true_node;
2425           if (min_gt)
2426             val = truthvalue_false_node;
2427         }
2428       else if (code == GE_EXPR)
2429         {
2430           if (!min_lt)
2431             val = truthvalue_true_node;
2432           if (max_lt)
2433             val = truthvalue_false_node;
2434         }
2435
2436       /* If primop0 was sign-extended and unsigned comparison specd,
2437          we did a signed comparison above using the signed type bounds.
2438          But the comparison we output must be unsigned.
2439
2440          Also, for inequalities, VAL is no good; but if the signed
2441          comparison had *any* fixed result, it follows that the
2442          unsigned comparison just tests the sign in reverse
2443          (positive values are LE, negative ones GE).
2444          So we can generate an unsigned comparison
2445          against an extreme value of the signed type.  */
2446
2447       if (unsignedp && !unsignedp0)
2448         {
2449           if (val != 0)
2450             switch (code)
2451               {
2452               case LT_EXPR:
2453               case GE_EXPR:
2454                 primop1 = TYPE_MIN_VALUE (type);
2455                 val = 0;
2456                 break;
2457
2458               case LE_EXPR:
2459               case GT_EXPR:
2460                 primop1 = TYPE_MAX_VALUE (type);
2461                 val = 0;
2462                 break;
2463
2464               default:
2465                 break;
2466               }
2467           type = c_common_unsigned_type (type);
2468         }
2469
2470       if (TREE_CODE (primop0) != INTEGER_CST)
2471         {
2472           if (val == truthvalue_false_node)
2473             warning (0, "comparison is always false due to limited range of data type");
2474           if (val == truthvalue_true_node)
2475             warning (0, "comparison is always true due to limited range of data type");
2476         }
2477
2478       if (val != 0)
2479         {
2480           /* Don't forget to evaluate PRIMOP0 if it has side effects.  */
2481           if (TREE_SIDE_EFFECTS (primop0))
2482             return build2 (COMPOUND_EXPR, TREE_TYPE (val), primop0, val);
2483           return val;
2484         }
2485
2486       /* Value is not predetermined, but do the comparison
2487          in the type of the operand that is not constant.
2488          TYPE is already properly set.  */
2489     }
2490
2491   /* If either arg is decimal float and the other is float, find the
2492      proper common type to use for comparison.  */
2493   else if (real1 && real2
2494            && (DECIMAL_FLOAT_MODE_P (TYPE_MODE (TREE_TYPE (primop0)))
2495                || DECIMAL_FLOAT_MODE_P (TYPE_MODE (TREE_TYPE (primop1)))))
2496     type = common_type (TREE_TYPE (primop0), TREE_TYPE (primop1));
2497
2498   else if (real1 && real2
2499            && (TYPE_PRECISION (TREE_TYPE (primop0))
2500                == TYPE_PRECISION (TREE_TYPE (primop1))))
2501     type = TREE_TYPE (primop0);
2502
2503   /* If args' natural types are both narrower than nominal type
2504      and both extend in the same manner, compare them
2505      in the type of the wider arg.
2506      Otherwise must actually extend both to the nominal
2507      common type lest different ways of extending
2508      alter the result.
2509      (eg, (short)-1 == (unsigned short)-1  should be 0.)  */
2510
2511   else if (unsignedp0 == unsignedp1 && real1 == real2
2512            && TYPE_PRECISION (TREE_TYPE (primop0)) < TYPE_PRECISION (*restype_ptr)
2513            && TYPE_PRECISION (TREE_TYPE (primop1)) < TYPE_PRECISION (*restype_ptr))
2514     {
2515       type = common_type (TREE_TYPE (primop0), TREE_TYPE (primop1));
2516       type = c_common_signed_or_unsigned_type (unsignedp0
2517                                                || TYPE_UNSIGNED (*restype_ptr),
2518                                                type);
2519       /* Make sure shorter operand is extended the right way
2520          to match the longer operand.  */
2521       primop0
2522         = convert (c_common_signed_or_unsigned_type (unsignedp0,
2523                                                      TREE_TYPE (primop0)),
2524                    primop0);
2525       primop1
2526         = convert (c_common_signed_or_unsigned_type (unsignedp1,
2527                                                      TREE_TYPE (primop1)),
2528                    primop1);
2529     }
2530   else
2531     {
2532       /* Here we must do the comparison on the nominal type
2533          using the args exactly as we received them.  */
2534       type = *restype_ptr;
2535       primop0 = op0;
2536       primop1 = op1;
2537
2538       if (!real1 && !real2 && integer_zerop (primop1)
2539           && TYPE_UNSIGNED (*restype_ptr))
2540         {
2541           tree value = 0;
2542           switch (code)
2543             {
2544             case GE_EXPR:
2545               /* All unsigned values are >= 0, so we warn if extra warnings
2546                  are requested.  However, if OP0 is a constant that is
2547                  >= 0, the signedness of the comparison isn't an issue,
2548                  so suppress the warning.  */
2549               if (extra_warnings && !in_system_header
2550                   && !(TREE_CODE (primop0) == INTEGER_CST
2551                        && !TREE_OVERFLOW (convert (c_common_signed_type (type),
2552                                                    primop0))))
2553                 warning (0, "comparison of unsigned expression >= 0 is always true");
2554               value = truthvalue_true_node;
2555               break;
2556
2557             case LT_EXPR:
2558               if (extra_warnings && !in_system_header
2559                   && !(TREE_CODE (primop0) == INTEGER_CST
2560                        && !TREE_OVERFLOW (convert (c_common_signed_type (type),
2561                                                    primop0))))
2562                 warning (0, "comparison of unsigned expression < 0 is always false");
2563               value = truthvalue_false_node;
2564               break;
2565
2566             default:
2567               break;
2568             }
2569
2570           if (value != 0)
2571             {
2572               /* Don't forget to evaluate PRIMOP0 if it has side effects.  */
2573               if (TREE_SIDE_EFFECTS (primop0))
2574                 return build2 (COMPOUND_EXPR, TREE_TYPE (value),
2575                                primop0, value);
2576               return value;
2577             }
2578         }
2579     }
2580
2581   *op0_ptr = convert (type, primop0);
2582   *op1_ptr = convert (type, primop1);
2583
2584   *restype_ptr = truthvalue_type_node;
2585
2586   return 0;
2587 }
2588 \f
2589 /* Return a tree for the sum or difference (RESULTCODE says which)
2590    of pointer PTROP and integer INTOP.  */
2591
2592 tree
2593 pointer_int_sum (enum tree_code resultcode, tree ptrop, tree intop)
2594 {
2595   tree size_exp, ret;
2596
2597   /* The result is a pointer of the same type that is being added.  */
2598
2599   tree result_type = TREE_TYPE (ptrop);
2600
2601   if (TREE_CODE (TREE_TYPE (result_type)) == VOID_TYPE)
2602     {
2603       if (pedantic || warn_pointer_arith)
2604         pedwarn ("pointer of type %<void *%> used in arithmetic");
2605       size_exp = integer_one_node;
2606     }
2607   else if (TREE_CODE (TREE_TYPE (result_type)) == FUNCTION_TYPE)
2608     {
2609       if (pedantic || warn_pointer_arith)
2610         pedwarn ("pointer to a function used in arithmetic");
2611       size_exp = integer_one_node;
2612     }
2613   else if (TREE_CODE (TREE_TYPE (result_type)) == METHOD_TYPE)
2614     {
2615       if (pedantic || warn_pointer_arith)
2616         pedwarn ("pointer to member function used in arithmetic");
2617       size_exp = integer_one_node;
2618     }
2619   else
2620     size_exp = size_in_bytes (TREE_TYPE (result_type));
2621
2622   /* We are manipulating pointer values, so we don't need to warn
2623      about relying on undefined signed overflow.  We disable the
2624      warning here because we use integer types so fold won't know that
2625      they are really pointers.  */
2626   fold_defer_overflow_warnings ();
2627
2628   /* If what we are about to multiply by the size of the elements
2629      contains a constant term, apply distributive law
2630      and multiply that constant term separately.
2631      This helps produce common subexpressions.  */
2632
2633   if ((TREE_CODE (intop) == PLUS_EXPR || TREE_CODE (intop) == MINUS_EXPR)
2634       && !TREE_CONSTANT (intop)
2635       && TREE_CONSTANT (TREE_OPERAND (intop, 1))
2636       && TREE_CONSTANT (size_exp)
2637       /* If the constant comes from pointer subtraction,
2638          skip this optimization--it would cause an error.  */
2639       && TREE_CODE (TREE_TYPE (TREE_OPERAND (intop, 0))) == INTEGER_TYPE
2640       /* If the constant is unsigned, and smaller than the pointer size,
2641          then we must skip this optimization.  This is because it could cause
2642          an overflow error if the constant is negative but INTOP is not.  */
2643       && (!TYPE_UNSIGNED (TREE_TYPE (intop))
2644           || (TYPE_PRECISION (TREE_TYPE (intop))
2645               == TYPE_PRECISION (TREE_TYPE (ptrop)))))
2646     {
2647       enum tree_code subcode = resultcode;
2648       tree int_type = TREE_TYPE (intop);
2649       if (TREE_CODE (intop) == MINUS_EXPR)
2650         subcode = (subcode == PLUS_EXPR ? MINUS_EXPR : PLUS_EXPR);
2651       /* Convert both subexpression types to the type of intop,
2652          because weird cases involving pointer arithmetic
2653          can result in a sum or difference with different type args.  */
2654       ptrop = build_binary_op (subcode, ptrop,
2655                                convert (int_type, TREE_OPERAND (intop, 1)), 1);
2656       intop = convert (int_type, TREE_OPERAND (intop, 0));
2657     }
2658
2659   /* Convert the integer argument to a type the same size as sizetype
2660      so the multiply won't overflow spuriously.  */
2661
2662   if (TYPE_PRECISION (TREE_TYPE (intop)) != TYPE_PRECISION (sizetype)
2663       || TYPE_UNSIGNED (TREE_TYPE (intop)) != TYPE_UNSIGNED (sizetype))
2664     intop = convert (c_common_type_for_size (TYPE_PRECISION (sizetype),
2665                                              TYPE_UNSIGNED (sizetype)), intop);
2666
2667   /* Replace the integer argument with a suitable product by the object size.
2668      Do this multiplication as signed, then convert to the appropriate
2669      pointer type (actually unsigned integral).  */
2670
2671   intop = convert (result_type,
2672                    build_binary_op (MULT_EXPR, intop,
2673                                     convert (TREE_TYPE (intop), size_exp), 1));
2674
2675   /* Create the sum or difference.  */
2676   ret = fold_build2 (resultcode, result_type, ptrop, intop);
2677
2678   fold_undefer_and_ignore_overflow_warnings ();
2679
2680   return ret;
2681 }
2682 \f
2683 /* Return whether EXPR is a declaration whose address can never be
2684    NULL.  */
2685
2686 bool
2687 decl_with_nonnull_addr_p (tree expr)
2688 {
2689   return (DECL_P (expr)
2690           && (TREE_CODE (expr) == PARM_DECL
2691               || TREE_CODE (expr) == LABEL_DECL
2692               || !DECL_WEAK (expr)));
2693 }
2694
2695 /* Prepare expr to be an argument of a TRUTH_NOT_EXPR,
2696    or for an `if' or `while' statement or ?..: exp.  It should already
2697    have been validated to be of suitable type; otherwise, a bad
2698    diagnostic may result.
2699
2700    This preparation consists of taking the ordinary
2701    representation of an expression expr and producing a valid tree
2702    boolean expression describing whether expr is nonzero.  We could
2703    simply always do build_binary_op (NE_EXPR, expr, truthvalue_false_node, 1),
2704    but we optimize comparisons, &&, ||, and !.
2705
2706    The resulting type should always be `truthvalue_type_node'.  */
2707
2708 tree
2709 c_common_truthvalue_conversion (tree expr)
2710 {
2711   switch (TREE_CODE (expr))
2712     {
2713     case EQ_EXPR:   case NE_EXPR:   case UNEQ_EXPR: case LTGT_EXPR:
2714     case LE_EXPR:   case GE_EXPR:   case LT_EXPR:   case GT_EXPR:
2715     case UNLE_EXPR: case UNGE_EXPR: case UNLT_EXPR: case UNGT_EXPR:
2716     case ORDERED_EXPR: case UNORDERED_EXPR:
2717       if (TREE_TYPE (expr) == truthvalue_type_node)
2718         return expr;
2719       return build2 (TREE_CODE (expr), truthvalue_type_node,
2720                      TREE_OPERAND (expr, 0), TREE_OPERAND (expr, 1));
2721
2722     case TRUTH_ANDIF_EXPR:
2723     case TRUTH_ORIF_EXPR:
2724     case TRUTH_AND_EXPR:
2725     case TRUTH_OR_EXPR:
2726     case TRUTH_XOR_EXPR:
2727       if (TREE_TYPE (expr) == truthvalue_type_node)
2728         return expr;
2729       return build2 (TREE_CODE (expr), truthvalue_type_node,
2730                  c_common_truthvalue_conversion (TREE_OPERAND (expr, 0)),
2731                  c_common_truthvalue_conversion (TREE_OPERAND (expr, 1)));
2732
2733     case TRUTH_NOT_EXPR:
2734       if (TREE_TYPE (expr) == truthvalue_type_node)
2735         return expr;
2736       return build1 (TREE_CODE (expr), truthvalue_type_node,
2737                  c_common_truthvalue_conversion (TREE_OPERAND (expr, 0)));
2738
2739     case ERROR_MARK:
2740       return expr;
2741
2742     case INTEGER_CST:
2743       return integer_zerop (expr) ? truthvalue_false_node
2744                                   : truthvalue_true_node;
2745
2746     case REAL_CST:
2747       return real_compare (NE_EXPR, &TREE_REAL_CST (expr), &dconst0)
2748              ? truthvalue_true_node
2749              : truthvalue_false_node;
2750
2751     case FUNCTION_DECL:
2752       expr = build_unary_op (ADDR_EXPR, expr, 0);
2753       /* Fall through.  */
2754
2755     case ADDR_EXPR:
2756       {
2757         tree inner = TREE_OPERAND (expr, 0);
2758         if (decl_with_nonnull_addr_p (inner))
2759           {
2760             /* Common Ada/Pascal programmer's mistake.  */
2761             warning (OPT_Waddress,
2762                      "the address of %qD will always evaluate as %<true%>",
2763                      inner);
2764             return truthvalue_true_node;
2765           }
2766
2767         /* If we still have a decl, it is possible for its address to
2768            be NULL, so we cannot optimize.  */
2769         if (DECL_P (inner))
2770           {
2771             gcc_assert (DECL_WEAK (inner));
2772             break;
2773           }
2774
2775         if (TREE_SIDE_EFFECTS (inner))
2776           return build2 (COMPOUND_EXPR, truthvalue_type_node,
2777                          inner, truthvalue_true_node);
2778         else
2779           return truthvalue_true_node;
2780       }
2781
2782     case COMPLEX_EXPR:
2783       return build_binary_op ((TREE_SIDE_EFFECTS (TREE_OPERAND (expr, 1))
2784                                ? TRUTH_OR_EXPR : TRUTH_ORIF_EXPR),
2785                 c_common_truthvalue_conversion (TREE_OPERAND (expr, 0)),
2786                 c_common_truthvalue_conversion (TREE_OPERAND (expr, 1)),
2787                               0);
2788
2789     case NEGATE_EXPR:
2790     case ABS_EXPR:
2791     case FLOAT_EXPR:
2792       /* These don't change whether an object is nonzero or zero.  */
2793       return c_common_truthvalue_conversion (TREE_OPERAND (expr, 0));
2794
2795     case LROTATE_EXPR:
2796     case RROTATE_EXPR:
2797       /* These don't change whether an object is zero or nonzero, but
2798          we can't ignore them if their second arg has side-effects.  */
2799       if (TREE_SIDE_EFFECTS (TREE_OPERAND (expr, 1)))
2800         return build2 (COMPOUND_EXPR, truthvalue_type_node,
2801                        TREE_OPERAND (expr, 1),
2802                        c_common_truthvalue_conversion (TREE_OPERAND (expr, 0)));
2803       else
2804         return c_common_truthvalue_conversion (TREE_OPERAND (expr, 0));
2805
2806     case COND_EXPR:
2807       /* Distribute the conversion into the arms of a COND_EXPR.  */
2808       return fold_build3 (COND_EXPR, truthvalue_type_node,
2809                 TREE_OPERAND (expr, 0),
2810                 c_common_truthvalue_conversion (TREE_OPERAND (expr, 1)),
2811                 c_common_truthvalue_conversion (TREE_OPERAND (expr, 2)));
2812
2813     case CONVERT_EXPR:
2814     case NOP_EXPR:
2815       /* Don't cancel the effect of a CONVERT_EXPR from a REFERENCE_TYPE,
2816          since that affects how `default_conversion' will behave.  */
2817       if (TREE_CODE (TREE_TYPE (expr)) == REFERENCE_TYPE
2818           || TREE_CODE (TREE_TYPE (TREE_OPERAND (expr, 0))) == REFERENCE_TYPE)
2819         break;
2820       /* If this is widening the argument, we can ignore it.  */
2821       if (TYPE_PRECISION (TREE_TYPE (expr))
2822           >= TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (expr, 0))))
2823         return c_common_truthvalue_conversion (TREE_OPERAND (expr, 0));
2824       break;
2825
2826     case MODIFY_EXPR:
2827       if (!TREE_NO_WARNING (expr)
2828           && warn_parentheses)
2829         {
2830           warning (OPT_Wparentheses,
2831                    "suggest parentheses around assignment used as truth value");
2832           TREE_NO_WARNING (expr) = 1;
2833         }
2834       break;
2835
2836     default:
2837       break;
2838     }
2839
2840   if (TREE_CODE (TREE_TYPE (expr)) == COMPLEX_TYPE)
2841     {
2842       tree t = save_expr (expr);
2843       return (build_binary_op
2844               ((TREE_SIDE_EFFECTS (expr)
2845                 ? TRUTH_OR_EXPR : TRUTH_ORIF_EXPR),
2846         c_common_truthvalue_conversion (build_unary_op (REALPART_EXPR, t, 0)),
2847         c_common_truthvalue_conversion (build_unary_op (IMAGPART_EXPR, t, 0)),
2848                0));
2849     }
2850
2851   return build_binary_op (NE_EXPR, expr, integer_zero_node, 1);
2852 }
2853 \f
2854 static void def_builtin_1  (enum built_in_function fncode,
2855                             const char *name,
2856                             enum built_in_class fnclass,
2857                             tree fntype, tree libtype,
2858                             bool both_p, bool fallback_p, bool nonansi_p,
2859                             tree fnattrs, bool implicit_p);
2860
2861 /* Make a variant type in the proper way for C/C++, propagating qualifiers
2862    down to the element type of an array.  */
2863
2864 tree
2865 c_build_qualified_type (tree type, int type_quals)
2866 {
2867   if (type == error_mark_node)
2868     return type;
2869
2870   if (TREE_CODE (type) == ARRAY_TYPE)
2871     {
2872       tree t;
2873       tree element_type = c_build_qualified_type (TREE_TYPE (type),
2874                                                   type_quals);
2875
2876       /* See if we already have an identically qualified type.  */
2877       for (t = TYPE_MAIN_VARIANT (type); t; t = TYPE_NEXT_VARIANT (t))
2878         {
2879           if (TYPE_QUALS (strip_array_types (t)) == type_quals
2880               && TYPE_NAME (t) == TYPE_NAME (type)
2881               && TYPE_CONTEXT (t) == TYPE_CONTEXT (type)
2882               && attribute_list_equal (TYPE_ATTRIBUTES (t),
2883                                        TYPE_ATTRIBUTES (type)))
2884             break;
2885         }
2886       if (!t)
2887         {
2888           t = build_variant_type_copy (type);
2889           TREE_TYPE (t) = element_type;
2890         }
2891       return t;
2892     }
2893
2894   /* A restrict-qualified pointer type must be a pointer to object or
2895      incomplete type.  Note that the use of POINTER_TYPE_P also allows
2896      REFERENCE_TYPEs, which is appropriate for C++.  */
2897   if ((type_quals & TYPE_QUAL_RESTRICT)
2898       && (!POINTER_TYPE_P (type)
2899           || !C_TYPE_OBJECT_OR_INCOMPLETE_P (TREE_TYPE (type))))
2900     {
2901       error ("invalid use of %<restrict%>");
2902       type_quals &= ~TYPE_QUAL_RESTRICT;
2903     }
2904
2905   return build_qualified_type (type, type_quals);
2906 }
2907
2908 /* Apply the TYPE_QUALS to the new DECL.  */
2909
2910 void
2911 c_apply_type_quals_to_decl (int type_quals, tree decl)
2912 {
2913   tree type = TREE_TYPE (decl);
2914
2915   if (type == error_mark_node)
2916     return;
2917
2918   if (((type_quals & TYPE_QUAL_CONST)
2919        || (type && TREE_CODE (type) == REFERENCE_TYPE))
2920       /* An object declared 'const' is only readonly after it is
2921          initialized.  We don't have any way of expressing this currently,
2922          so we need to be conservative and unset TREE_READONLY for types
2923          with constructors.  Otherwise aliasing code will ignore stores in
2924          an inline constructor.  */
2925       && !(type && TYPE_NEEDS_CONSTRUCTING (type)))
2926     TREE_READONLY (decl) = 1;
2927   if (type_quals & TYPE_QUAL_VOLATILE)
2928     {
2929       TREE_SIDE_EFFECTS (decl) = 1;
2930       TREE_THIS_VOLATILE (decl) = 1;
2931     }
2932   if (type_quals & TYPE_QUAL_RESTRICT)
2933     {
2934       while (type && TREE_CODE (type) == ARRAY_TYPE)
2935         /* Allow 'restrict' on arrays of pointers.
2936            FIXME currently we just ignore it.  */
2937         type = TREE_TYPE (type);
2938       if (!type
2939           || !POINTER_TYPE_P (type)
2940           || !C_TYPE_OBJECT_OR_INCOMPLETE_P (TREE_TYPE (type)))
2941         error ("invalid use of %<restrict%>");
2942       else if (flag_strict_aliasing && type == TREE_TYPE (decl))
2943         /* Indicate we need to make a unique alias set for this pointer.
2944            We can't do it here because it might be pointing to an
2945            incomplete type.  */
2946         DECL_POINTER_ALIAS_SET (decl) = -2;
2947     }
2948 }
2949
2950 /* Hash function for the problem of multiple type definitions in
2951    different files.  This must hash all types that will compare
2952    equal via comptypes to the same value.  In practice it hashes
2953    on some of the simple stuff and leaves the details to comptypes.  */
2954
2955 static hashval_t
2956 c_type_hash (const void *p)
2957 {
2958   int i = 0;
2959   int shift, size;
2960   tree t = (tree) p;
2961   tree t2;
2962   switch (TREE_CODE (t))
2963     {
2964     /* For pointers, hash on pointee type plus some swizzling.  */
2965     case POINTER_TYPE:
2966       return c_type_hash (TREE_TYPE (t)) ^ 0x3003003;
2967     /* Hash on number of elements and total size.  */
2968     case ENUMERAL_TYPE:
2969       shift = 3;
2970       t2 = TYPE_VALUES (t);
2971       break;
2972     case RECORD_TYPE:
2973       shift = 0;
2974       t2 = TYPE_FIELDS (t);
2975       break;
2976     case QUAL_UNION_TYPE:
2977       shift = 1;
2978       t2 = TYPE_FIELDS (t);
2979       break;
2980     case UNION_TYPE:
2981       shift = 2;
2982       t2 = TYPE_FIELDS (t);
2983       break;
2984     default:
2985       gcc_unreachable ();
2986     }
2987   for (; t2; t2 = TREE_CHAIN (t2))
2988     i++;
2989   size = TREE_INT_CST_LOW (TYPE_SIZE (t));
2990   return ((size << 24) | (i << shift));
2991 }
2992
2993 static GTY((param_is (union tree_node))) htab_t type_hash_table;
2994
2995 /* Return the typed-based alias set for T, which may be an expression
2996    or a type.  Return -1 if we don't do anything special.  */
2997
2998 HOST_WIDE_INT
2999 c_common_get_alias_set (tree t)
3000 {
3001   tree u;
3002   PTR *slot;
3003
3004   /* Permit type-punning when accessing a union, provided the access
3005      is directly through the union.  For example, this code does not
3006      permit taking the address of a union member and then storing
3007      through it.  Even the type-punning allowed here is a GCC
3008      extension, albeit a common and useful one; the C standard says
3009      that such accesses have implementation-defined behavior.  */
3010   for (u = t;
3011        TREE_CODE (u) == COMPONENT_REF || TREE_CODE (u) == ARRAY_REF;
3012        u = TREE_OPERAND (u, 0))
3013     if (TREE_CODE (u) == COMPONENT_REF
3014         && TREE_CODE (TREE_TYPE (TREE_OPERAND (u, 0))) == UNION_TYPE)
3015       return 0;
3016
3017   /* That's all the expressions we handle specially.  */
3018   if (!TYPE_P (t))
3019     return -1;
3020
3021   /* The C standard guarantees that any object may be accessed via an
3022      lvalue that has character type.  */
3023   if (t == char_type_node
3024       || t == signed_char_type_node
3025       || t == unsigned_char_type_node)
3026     return 0;
3027
3028   /* If it has the may_alias attribute, it can alias anything.  */
3029   if (lookup_attribute ("may_alias", TYPE_ATTRIBUTES (t)))
3030     return 0;
3031
3032   /* The C standard specifically allows aliasing between signed and
3033      unsigned variants of the same type.  We treat the signed
3034      variant as canonical.  */
3035   if (TREE_CODE (t) == INTEGER_TYPE && TYPE_UNSIGNED (t))
3036     {
3037       tree t1 = c_common_signed_type (t);
3038
3039       /* t1 == t can happen for boolean nodes which are always unsigned.  */
3040       if (t1 != t)
3041         return get_alias_set (t1);
3042     }
3043   else if (POINTER_TYPE_P (t))
3044     {
3045       tree t1;
3046
3047       /* Unfortunately, there is no canonical form of a pointer type.
3048          In particular, if we have `typedef int I', then `int *', and
3049          `I *' are different types.  So, we have to pick a canonical
3050          representative.  We do this below.
3051
3052          Technically, this approach is actually more conservative that
3053          it needs to be.  In particular, `const int *' and `int *'
3054          should be in different alias sets, according to the C and C++
3055          standard, since their types are not the same, and so,
3056          technically, an `int **' and `const int **' cannot point at
3057          the same thing.
3058
3059          But, the standard is wrong.  In particular, this code is
3060          legal C++:
3061
3062             int *ip;
3063             int **ipp = &ip;
3064             const int* const* cipp = ipp;
3065
3066          And, it doesn't make sense for that to be legal unless you
3067          can dereference IPP and CIPP.  So, we ignore cv-qualifiers on
3068          the pointed-to types.  This issue has been reported to the
3069          C++ committee.  */
3070       t1 = build_type_no_quals (t);
3071       if (t1 != t)
3072         return get_alias_set (t1);
3073     }
3074
3075   /* Handle the case of multiple type nodes referring to "the same" type,
3076      which occurs with IMA.  These share an alias set.  FIXME:  Currently only
3077      C90 is handled.  (In C99 type compatibility is not transitive, which
3078      complicates things mightily. The alias set splay trees can theoretically
3079      represent this, but insertion is tricky when you consider all the
3080      different orders things might arrive in.) */
3081
3082   if (c_language != clk_c || flag_isoc99)
3083     return -1;
3084
3085   /* Save time if there's only one input file.  */
3086   if (num_in_fnames == 1)
3087     return -1;
3088
3089   /* Pointers need special handling if they point to any type that
3090      needs special handling (below).  */
3091   if (TREE_CODE (t) == POINTER_TYPE)
3092     {
3093       tree t2;
3094       /* Find bottom type under any nested POINTERs.  */
3095       for (t2 = TREE_TYPE (t);
3096      TREE_CODE (t2) == POINTER_TYPE;
3097      t2 = TREE_TYPE (t2))
3098   ;
3099       if (TREE_CODE (t2) != RECORD_TYPE
3100     && TREE_CODE (t2) != ENUMERAL_TYPE
3101     && TREE_CODE (t2) != QUAL_UNION_TYPE
3102     && TREE_CODE (t2) != UNION_TYPE)
3103   return -1;
3104       if (TYPE_SIZE (t2) == 0)
3105   return -1;
3106     }
3107   /* These are the only cases that need special handling.  */
3108   if (TREE_CODE (t) != RECORD_TYPE
3109       && TREE_CODE (t) != ENUMERAL_TYPE
3110       && TREE_CODE (t) != QUAL_UNION_TYPE
3111       && TREE_CODE (t) != UNION_TYPE
3112       && TREE_CODE (t) != POINTER_TYPE)
3113     return -1;
3114   /* Undefined? */
3115   if (TYPE_SIZE (t) == 0)
3116     return -1;
3117
3118   /* Look up t in hash table.  Only one of the compatible types within each
3119      alias set is recorded in the table.  */
3120   if (!type_hash_table)
3121     type_hash_table = htab_create_ggc (1021, c_type_hash,
3122             (htab_eq) lang_hooks.types_compatible_p,
3123             NULL);
3124   slot = htab_find_slot (type_hash_table, t, INSERT);
3125   if (*slot != NULL)
3126     {
3127       TYPE_ALIAS_SET (t) = TYPE_ALIAS_SET ((tree)*slot);
3128       return TYPE_ALIAS_SET ((tree)*slot);
3129     }
3130   else
3131     /* Our caller will assign and record (in t) a new alias set; all we need
3132        to do is remember t in the hash table.  */
3133     *slot = t;
3134
3135   return -1;
3136 }
3137 \f
3138 /* Compute the value of 'sizeof (TYPE)' or '__alignof__ (TYPE)', where the
3139    second parameter indicates which OPERATOR is being applied.  The COMPLAIN
3140    flag controls whether we should diagnose possibly ill-formed
3141    constructs or not.  */
3142
3143 tree
3144 c_sizeof_or_alignof_type (tree type, bool is_sizeof, int complain)
3145 {
3146   const char *op_name;
3147   tree value = NULL;
3148   enum tree_code type_code = TREE_CODE (type);
3149
3150   op_name = is_sizeof ? "sizeof" : "__alignof__";
3151
3152   if (type_code == FUNCTION_TYPE)
3153     {
3154       if (is_sizeof)
3155         {
3156           if (complain && (pedantic || warn_pointer_arith))
3157             pedwarn ("invalid application of %<sizeof%> to a function type");
3158           value = size_one_node;
3159         }
3160       else
3161         value = size_int (FUNCTION_BOUNDARY / BITS_PER_UNIT);
3162     }
3163   else if (type_code == VOID_TYPE || type_code == ERROR_MARK)
3164     {
3165       if (type_code == VOID_TYPE
3166           && complain && (pedantic || warn_pointer_arith))
3167         pedwarn ("invalid application of %qs to a void type", op_name);
3168       value = size_one_node;
3169     }
3170   else if (!COMPLETE_TYPE_P (type))
3171     {
3172       if (complain)
3173         error ("invalid application of %qs to incomplete type %qT ",
3174                op_name, type);
3175       value = size_zero_node;
3176     }
3177   else
3178     {
3179       if (is_sizeof)
3180         /* Convert in case a char is more than one unit.  */
3181         value = size_binop (CEIL_DIV_EXPR, TYPE_SIZE_UNIT (type),
3182                             size_int (TYPE_PRECISION (char_type_node)
3183                                       / BITS_PER_UNIT));
3184       else
3185         value = size_int (TYPE_ALIGN_UNIT (type));
3186     }
3187
3188   /* VALUE will have an integer type with TYPE_IS_SIZETYPE set.
3189      TYPE_IS_SIZETYPE means that certain things (like overflow) will
3190      never happen.  However, this node should really have type
3191      `size_t', which is just a typedef for an ordinary integer type.  */
3192   value = fold_convert (size_type_node, value);
3193   gcc_assert (!TYPE_IS_SIZETYPE (TREE_TYPE (value)));
3194
3195   return value;
3196 }
3197
3198 /* Implement the __alignof keyword: Return the minimum required
3199    alignment of EXPR, measured in bytes.  For VAR_DECL's and
3200    FIELD_DECL's return DECL_ALIGN (which can be set from an
3201    "aligned" __attribute__ specification).  */
3202
3203 tree
3204 c_alignof_expr (tree expr)
3205 {
3206   tree t;
3207
3208   if (TREE_CODE (expr) == VAR_DECL)
3209     t = size_int (DECL_ALIGN_UNIT (expr));
3210
3211   else if (TREE_CODE (expr) == COMPONENT_REF
3212            && DECL_C_BIT_FIELD (TREE_OPERAND (expr, 1)))
3213     {
3214       error ("%<__alignof%> applied to a bit-field");
3215       t = size_one_node;
3216     }
3217   else if (TREE_CODE (expr) == COMPONENT_REF
3218            && TREE_CODE (TREE_OPERAND (expr, 1)) == FIELD_DECL)
3219     t = size_int (DECL_ALIGN_UNIT (TREE_OPERAND (expr, 1)));
3220
3221   else if (TREE_CODE (expr) == INDIRECT_REF)
3222     {
3223       tree t = TREE_OPERAND (expr, 0);
3224       tree best = t;
3225       int bestalign = TYPE_ALIGN (TREE_TYPE (TREE_TYPE (t)));
3226
3227       while ((TREE_CODE (t) == NOP_EXPR || TREE_CODE (t) == CONVERT_EXPR)
3228              && TREE_CODE (TREE_TYPE (TREE_OPERAND (t, 0))) == POINTER_TYPE)
3229         {
3230           int thisalign;
3231
3232           t = TREE_OPERAND (t, 0);
3233           thisalign = TYPE_ALIGN (TREE_TYPE (TREE_TYPE (t)));
3234           if (thisalign > bestalign)
3235             best = t, bestalign = thisalign;
3236         }
3237       return c_alignof (TREE_TYPE (TREE_TYPE (best)));
3238     }
3239   else
3240     return c_alignof (TREE_TYPE (expr));
3241
3242   return fold_convert (size_type_node, t);
3243 }
3244 \f
3245 /* Handle C and C++ default attributes.  */
3246
3247 enum built_in_attribute
3248 {
3249 #define DEF_ATTR_NULL_TREE(ENUM) ENUM,
3250 #define DEF_ATTR_INT(ENUM, VALUE) ENUM,
3251 #define DEF_ATTR_IDENT(ENUM, STRING) ENUM,
3252 #define DEF_ATTR_TREE_LIST(ENUM, PURPOSE, VALUE, CHAIN) ENUM,
3253 #include "builtin-attrs.def"
3254 #undef DEF_ATTR_NULL_TREE
3255 #undef DEF_ATTR_INT
3256 #undef DEF_ATTR_IDENT
3257 #undef DEF_ATTR_TREE_LIST
3258   ATTR_LAST
3259 };
3260
3261 static GTY(()) tree built_in_attributes[(int) ATTR_LAST];
3262
3263 static void c_init_attributes (void);
3264
3265 enum c_builtin_type
3266 {
3267 #define DEF_PRIMITIVE_TYPE(NAME, VALUE) NAME,
3268 #define DEF_FUNCTION_TYPE_0(NAME, RETURN) NAME,
3269 #define DEF_FUNCTION_TYPE_1(NAME, RETURN, ARG1) NAME,
3270 #define DEF_FUNCTION_TYPE_2(NAME, RETURN, ARG1, ARG2) NAME,
3271 #define DEF_FUNCTION_TYPE_3(NAME, RETURN, ARG1, ARG2, ARG3) NAME,
3272 #define DEF_FUNCTION_TYPE_4(NAME, RETURN, ARG1, ARG2, ARG3, ARG4) NAME,
3273 #define DEF_FUNCTION_TYPE_5(NAME, RETURN, ARG1, ARG2, ARG3, ARG4, ARG5) NAME,
3274 #define DEF_FUNCTION_TYPE_6(NAME, RETURN, ARG1, ARG2, ARG3, ARG4, ARG5, ARG6) NAME,
3275 #define DEF_FUNCTION_TYPE_7(NAME, RETURN, ARG1, ARG2, ARG3, ARG4, ARG5, ARG6, ARG7) NAME,
3276 #define DEF_FUNCTION_TYPE_VAR_0(NAME, RETURN) NAME,
3277 #define DEF_FUNCTION_TYPE_VAR_1(NAME, RETURN, ARG1) NAME,
3278 #define DEF_FUNCTION_TYPE_VAR_2(NAME, RETURN, ARG1, ARG2) NAME,
3279 #define DEF_FUNCTION_TYPE_VAR_3(NAME, RETURN, ARG1, ARG2, ARG3) NAME,
3280 #define DEF_FUNCTION_TYPE_VAR_4(NAME, RETURN, ARG1, ARG2, ARG3, ARG4) NAME,
3281 #define DEF_FUNCTION_TYPE_VAR_5(NAME, RETURN, ARG1, ARG2, ARG3, ARG4, ARG6) \
3282   NAME,
3283 #define DEF_POINTER_TYPE(NAME, TYPE) NAME,
3284 #include "builtin-types.def"
3285 #undef DEF_PRIMITIVE_TYPE
3286 #undef DEF_FUNCTION_TYPE_0
3287 #undef DEF_FUNCTION_TYPE_1
3288 #undef DEF_FUNCTION_TYPE_2
3289 #undef DEF_FUNCTION_TYPE_3
3290 #undef DEF_FUNCTION_TYPE_4
3291 #undef DEF_FUNCTION_TYPE_5
3292 #undef DEF_FUNCTION_TYPE_6
3293 #undef DEF_FUNCTION_TYPE_7
3294 #undef DEF_FUNCTION_TYPE_VAR_0
3295 #undef DEF_FUNCTION_TYPE_VAR_1
3296 #undef DEF_FUNCTION_TYPE_VAR_2
3297 #undef DEF_FUNCTION_TYPE_VAR_3
3298 #undef DEF_FUNCTION_TYPE_VAR_4
3299 #undef DEF_FUNCTION_TYPE_VAR_5
3300 #undef DEF_POINTER_TYPE
3301   BT_LAST
3302 };
3303
3304 typedef enum c_builtin_type builtin_type;
3305
3306 /* A temporary array for c_common_nodes_and_builtins.  Used in
3307    communication with def_fn_type.  */
3308 static tree builtin_types[(int) BT_LAST + 1];
3309
3310 /* A helper function for c_common_nodes_and_builtins.  Build function type
3311    for DEF with return type RET and N arguments.  If VAR is true, then the
3312    function should be variadic after those N arguments.
3313
3314    Takes special care not to ICE if any of the types involved are
3315    error_mark_node, which indicates that said type is not in fact available
3316    (see builtin_type_for_size).  In which case the function type as a whole
3317    should be error_mark_node.  */
3318
3319 static void
3320 def_fn_type (builtin_type def, builtin_type ret, bool var, int n, ...)
3321 {
3322   tree args = NULL, t;
3323   va_list list;
3324   int i;
3325
3326   va_start (list, n);
3327   for (i = 0; i < n; ++i)
3328     {
3329       builtin_type a = va_arg (list, builtin_type);
3330       t = builtin_types[a];
3331       if (t == error_mark_node)
3332         goto egress;
3333       args = tree_cons (NULL_TREE, t, args);
3334     }
3335   va_end (list);
3336
3337   args = nreverse (args);
3338   if (!var)
3339     args = chainon (args, void_list_node);
3340
3341   t = builtin_types[ret];
3342   if (t == error_mark_node)
3343     goto egress;
3344   t = build_function_type (t, args);
3345
3346  egress:
3347   builtin_types[def] = t;
3348 }
3349
3350 /* Build builtin functions common to both C and C++ language
3351    frontends.  */
3352
3353 static void
3354 c_define_builtins (tree va_list_ref_type_node, tree va_list_arg_type_node)
3355 {
3356 #define DEF_PRIMITIVE_TYPE(ENUM, VALUE) \
3357   builtin_types[ENUM] = VALUE;
3358 #define DEF_FUNCTION_TYPE_0(ENUM, RETURN) \
3359   def_fn_type (ENUM, RETURN, 0, 0);
3360 #define DEF_FUNCTION_TYPE_1(ENUM, RETURN, ARG1) \
3361   def_fn_type (ENUM, RETURN, 0, 1, ARG1);
3362 #define DEF_FUNCTION_TYPE_2(ENUM, RETURN, ARG1, ARG2) \
3363   def_fn_type (ENUM, RETURN, 0, 2, ARG1, ARG2);
3364 #define DEF_FUNCTION_TYPE_3(ENUM, RETURN, ARG1, ARG2, ARG3) \
3365   def_fn_type (ENUM, RETURN, 0, 3, ARG1, ARG2, ARG3);
3366 #define DEF_FUNCTION_TYPE_4(ENUM, RETURN, ARG1, ARG2, ARG3, ARG4) \
3367   def_fn_type (ENUM, RETURN, 0, 4, ARG1, ARG2, ARG3, ARG4);
3368 #define DEF_FUNCTION_TYPE_5(ENUM, RETURN, ARG1, ARG2, ARG3, ARG4, ARG5) \
3369   def_fn_type (ENUM, RETURN, 0, 5, ARG1, ARG2, ARG3, ARG4, ARG5);
3370 #define DEF_FUNCTION_TYPE_6(ENUM, RETURN, ARG1, ARG2, ARG3, ARG4, ARG5, \
3371                             ARG6)                                       \
3372   def_fn_type (ENUM, RETURN, 0, 6, ARG1, ARG2, ARG3, ARG4, ARG5, ARG6);
3373 #define DEF_FUNCTION_TYPE_7(ENUM, RETURN, ARG1, ARG2, ARG3, ARG4, ARG5, \
3374                             ARG6, ARG7)                                 \
3375   def_fn_type (ENUM, RETURN, 0, 7, ARG1, ARG2, ARG3, ARG4, ARG5, ARG6, ARG7);
3376 #define DEF_FUNCTION_TYPE_VAR_0(ENUM, RETURN) \
3377   def_fn_type (ENUM, RETURN, 1, 0);
3378 #define DEF_FUNCTION_TYPE_VAR_1(ENUM, RETURN, ARG1) \
3379   def_fn_type (ENUM, RETURN, 1, 1, ARG1);
3380 #define DEF_FUNCTION_TYPE_VAR_2(ENUM, RETURN, ARG1, ARG2) \
3381   def_fn_type (ENUM, RETURN, 1, 2, ARG1, ARG2);
3382 #define DEF_FUNCTION_TYPE_VAR_3(ENUM, RETURN, ARG1, ARG2, ARG3) \
3383   def_fn_type (ENUM, RETURN, 1, 3, ARG1, ARG2, ARG3);
3384 #define DEF_FUNCTION_TYPE_VAR_4(ENUM, RETURN, ARG1, ARG2, ARG3, ARG4) \
3385   def_fn_type (ENUM, RETURN, 1, 4, ARG1, ARG2, ARG3, ARG4);
3386 #define DEF_FUNCTION_TYPE_VAR_5(ENUM, RETURN, ARG1, ARG2, ARG3, ARG4, ARG5) \
3387   def_fn_type (ENUM, RETURN, 1, 5, ARG1, ARG2, ARG3, ARG4, ARG5);
3388 #define DEF_POINTER_TYPE(ENUM, TYPE) \
3389   builtin_types[(int) ENUM] = build_pointer_type (builtin_types[(int) TYPE]);
3390
3391 #include "builtin-types.def"
3392
3393 #undef DEF_PRIMITIVE_TYPE
3394 #undef DEF_FUNCTION_TYPE_1
3395 #undef DEF_FUNCTION_TYPE_2
3396 #undef DEF_FUNCTION_TYPE_3
3397 #undef DEF_FUNCTION_TYPE_4
3398 #undef DEF_FUNCTION_TYPE_5
3399 #undef DEF_FUNCTION_TYPE_6
3400 #undef DEF_FUNCTION_TYPE_VAR_0
3401 #undef DEF_FUNCTION_TYPE_VAR_1
3402 #undef DEF_FUNCTION_TYPE_VAR_2
3403 #undef DEF_FUNCTION_TYPE_VAR_3
3404 #undef DEF_FUNCTION_TYPE_VAR_4
3405 #undef DEF_FUNCTION_TYPE_VAR_5
3406 #undef DEF_POINTER_TYPE
3407   builtin_types[(int) BT_LAST] = NULL_TREE;
3408
3409   c_init_attributes ();
3410
3411 #define DEF_BUILTIN(ENUM, NAME, CLASS, TYPE, LIBTYPE, BOTH_P, FALLBACK_P, \
3412                     NONANSI_P, ATTRS, IMPLICIT, COND)                   \
3413   if (NAME && COND)                                                     \
3414     def_builtin_1 (ENUM, NAME, CLASS,                                   \
3415                    builtin_types[(int) TYPE],                           \
3416                    builtin_types[(int) LIBTYPE],                        \
3417                    BOTH_P, FALLBACK_P, NONANSI_P,                       \
3418                    built_in_attributes[(int) ATTRS], IMPLICIT);
3419 #include "builtins.def"
3420 #undef DEF_BUILTIN
3421
3422   build_common_builtin_nodes ();
3423
3424   targetm.init_builtins ();
3425   if (flag_mudflap)
3426     mudflap_init ();
3427 }
3428
3429 /* Build tree nodes and builtin functions common to both C and C++ language
3430    frontends.  */
3431
3432 void
3433 c_common_nodes_and_builtins (void)
3434 {
3435   int wchar_type_size;
3436   tree array_domain_type;
3437   tree va_list_ref_type_node;
3438   tree va_list_arg_type_node;
3439
3440   /* Define `int' and `char' first so that dbx will output them first.  */
3441   record_builtin_type (RID_INT, NULL, integer_type_node);
3442   record_builtin_type (RID_CHAR, "char", char_type_node);
3443
3444   /* `signed' is the same as `int'.  FIXME: the declarations of "signed",
3445      "unsigned long", "long long unsigned" and "unsigned short" were in C++
3446      but not C.  Are the conditionals here needed?  */
3447   if (c_dialect_cxx ())
3448     record_builtin_type (RID_SIGNED, NULL, integer_type_node);
3449   record_builtin_type (RID_LONG, "long int", long_integer_type_node);
3450   record_builtin_type (RID_UNSIGNED, "unsigned int", unsigned_type_node);
3451   record_builtin_type (RID_MAX, "long unsigned int",
3452                        long_unsigned_type_node);
3453   if (c_dialect_cxx ())
3454     record_builtin_type (RID_MAX, "unsigned long", long_unsigned_type_node);
3455   record_builtin_type (RID_MAX, "long long int",
3456                        long_long_integer_type_node);
3457   record_builtin_type (RID_MAX, "long long unsigned int",
3458                        long_long_unsigned_type_node);
3459   if (c_dialect_cxx ())
3460     record_builtin_type (RID_MAX, "long long unsigned",
3461                          long_long_unsigned_type_node);
3462   record_builtin_type (RID_SHORT, "short int", short_integer_type_node);
3463   record_builtin_type (RID_MAX, "short unsigned int",
3464                        short_unsigned_type_node);
3465   if (c_dialect_cxx ())
3466     record_builtin_type (RID_MAX, "unsigned short",
3467                          short_unsigned_type_node);
3468
3469   /* Define both `signed char' and `unsigned char'.  */
3470   record_builtin_type (RID_MAX, "signed char", signed_char_type_node);
3471   record_builtin_type (RID_MAX, "unsigned char", unsigned_char_type_node);
3472
3473   /* These are types that c_common_type_for_size and
3474      c_common_type_for_mode use.  */
3475   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
3476                                          intQI_type_node));
3477   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
3478                                          intHI_type_node));
3479   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
3480                                          intSI_type_node));
3481   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
3482                                          intDI_type_node));
3483 #if HOST_BITS_PER_WIDE_INT >= 64
3484   if (targetm.scalar_mode_supported_p (TImode))
3485     lang_hooks.decls.pushdecl (build_decl (TYPE_DECL,
3486                                            get_identifier ("__int128_t"),
3487                                            intTI_type_node));
3488 #endif
3489   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
3490                                          unsigned_intQI_type_node));
3491   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
3492                                          unsigned_intHI_type_node));
3493   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
3494                                          unsigned_intSI_type_node));
3495   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
3496                                          unsigned_intDI_type_node));
3497 #if HOST_BITS_PER_WIDE_INT >= 64
3498   if (targetm.scalar_mode_supported_p (TImode))
3499     lang_hooks.decls.pushdecl (build_decl (TYPE_DECL,
3500                                            get_identifier ("__uint128_t"),
3501                                            unsigned_intTI_type_node));
3502 #endif
3503
3504   /* Create the widest literal types.  */
3505   widest_integer_literal_type_node
3506     = make_signed_type (HOST_BITS_PER_WIDE_INT * 2);
3507   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
3508                                          widest_integer_literal_type_node));
3509
3510   widest_unsigned_literal_type_node
3511     = make_unsigned_type (HOST_BITS_PER_WIDE_INT * 2);
3512   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
3513                                          widest_unsigned_literal_type_node));
3514
3515   /* `unsigned long' is the standard type for sizeof.
3516      Note that stddef.h uses `unsigned long',
3517      and this must agree, even if long and int are the same size.  */
3518   size_type_node =
3519     TREE_TYPE (identifier_global_value (get_identifier (SIZE_TYPE)));
3520   signed_size_type_node = c_common_signed_type (size_type_node);
3521   set_sizetype (size_type_node);
3522
3523   pid_type_node =
3524     TREE_TYPE (identifier_global_value (get_identifier (PID_TYPE)));
3525
3526   build_common_tree_nodes_2 (flag_short_double);
3527
3528   record_builtin_type (RID_FLOAT, NULL, float_type_node);
3529   record_builtin_type (RID_DOUBLE, NULL, double_type_node);
3530   record_builtin_type (RID_MAX, "long double", long_double_type_node);
3531
3532   /* Only supported decimal floating point extension if the target
3533      actually supports underlying modes. */
3534   if (targetm.scalar_mode_supported_p (SDmode)
3535       && targetm.scalar_mode_supported_p (DDmode)
3536       && targetm.scalar_mode_supported_p (TDmode))
3537     {
3538       record_builtin_type (RID_DFLOAT32, NULL, dfloat32_type_node);
3539       record_builtin_type (RID_DFLOAT64, NULL, dfloat64_type_node);
3540       record_builtin_type (RID_DFLOAT128, NULL, dfloat128_type_node);
3541     }
3542
3543   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL,
3544                                          get_identifier ("complex int"),
3545                                          complex_integer_type_node));
3546   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL,
3547                                          get_identifier ("complex float"),
3548                                          complex_float_type_node));
3549   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL,
3550                                          get_identifier ("complex double"),
3551                                          complex_double_type_node));
3552   lang_hooks.decls.pushdecl
3553     (build_decl (TYPE_DECL, get_identifier ("complex long double"),
3554                  complex_long_double_type_node));
3555
3556   if (c_dialect_cxx ())
3557     /* For C++, make fileptr_type_node a distinct void * type until
3558        FILE type is defined.  */
3559     fileptr_type_node = build_variant_type_copy (ptr_type_node);
3560
3561   record_builtin_type (RID_VOID, NULL, void_type_node);
3562
3563   /* Set the TYPE_NAME for any variants that were built before
3564      record_builtin_type gave names to the built-in types. */
3565   {
3566     tree void_name = TYPE_NAME (void_type_node);
3567     TYPE_NAME (void_type_node) = NULL_TREE;
3568     TYPE_NAME (build_qualified_type (void_type_node, TYPE_QUAL_CONST))
3569       = void_name;
3570     TYPE_NAME (void_type_node) = void_name;
3571   }
3572
3573   /* This node must not be shared.  */
3574   void_zero_node = make_node (INTEGER_CST);
3575   TREE_TYPE (void_zero_node) = void_type_node;
3576
3577   void_list_node = build_void_list_node ();
3578
3579   /* Make a type to be the domain of a few array types
3580      whose domains don't really matter.
3581      200 is small enough that it always fits in size_t
3582      and large enough that it can hold most function names for the
3583      initializations of __FUNCTION__ and __PRETTY_FUNCTION__.  */
3584   array_domain_type = build_index_type (size_int (200));
3585
3586   /* Make a type for arrays of characters.
3587      With luck nothing will ever really depend on the length of this
3588      array type.  */
3589   char_array_type_node
3590     = build_array_type (char_type_node, array_domain_type);
3591
3592   /* Likewise for arrays of ints.  */
3593   int_array_type_node
3594     = build_array_type (integer_type_node, array_domain_type);
3595
3596   string_type_node = build_pointer_type (char_type_node);
3597   const_string_type_node
3598     = build_pointer_type (build_qualified_type
3599                           (char_type_node, TYPE_QUAL_CONST));
3600
3601   /* This is special for C++ so functions can be overloaded.  */
3602   wchar_type_node = get_identifier (MODIFIED_WCHAR_TYPE);
3603   wchar_type_node = TREE_TYPE (identifier_global_value (wchar_type_node));
3604   wchar_type_size = TYPE_PRECISION (wchar_type_node);
3605   if (c_dialect_cxx ())
3606     {
3607       if (TYPE_UNSIGNED (wchar_type_node))
3608         wchar_type_node = make_unsigned_type (wchar_type_size);
3609       else
3610         wchar_type_node = make_signed_type (wchar_type_size);
3611       record_builtin_type (RID_WCHAR, "wchar_t", wchar_type_node);
3612     }
3613   else
3614     {
3615       signed_wchar_type_node = c_common_signed_type (wchar_type_node);
3616       unsigned_wchar_type_node = c_common_unsigned_type (wchar_type_node);
3617     }
3618
3619   /* This is for wide string constants.  */
3620   wchar_array_type_node
3621     = build_array_type (wchar_type_node, array_domain_type);
3622
3623   wint_type_node =
3624     TREE_TYPE (identifier_global_value (get_identifier (WINT_TYPE)));
3625
3626   intmax_type_node =
3627     TREE_TYPE (identifier_global_value (get_identifier (INTMAX_TYPE)));
3628   uintmax_type_node =
3629     TREE_TYPE (identifier_global_value (get_identifier (UINTMAX_TYPE)));
3630
3631   default_function_type = build_function_type (integer_type_node, NULL_TREE);
3632   ptrdiff_type_node
3633     = TREE_TYPE (identifier_global_value (get_identifier (PTRDIFF_TYPE)));
3634   unsigned_ptrdiff_type_node = c_common_unsigned_type (ptrdiff_type_node);
3635
3636   lang_hooks.decls.pushdecl
3637     (build_decl (TYPE_DECL, get_identifier ("__builtin_va_list"),
3638                  va_list_type_node));
3639
3640   if (TREE_CODE (va_list_type_node) == ARRAY_TYPE)
3641     {
3642       va_list_arg_type_node = va_list_ref_type_node =
3643         build_pointer_type (TREE_TYPE (va_list_type_node));
3644     }
3645   else
3646     {
3647       va_list_arg_type_node = va_list_type_node;
3648       va_list_ref_type_node = build_reference_type (va_list_type_node);
3649     }
3650
3651   if (!flag_preprocess_only)
3652     c_define_builtins (va_list_ref_type_node, va_list_arg_type_node);
3653
3654   main_identifier_node = get_identifier ("main");
3655
3656   /* Create the built-in __null node.  It is important that this is
3657      not shared.  */
3658   null_node = make_node (INTEGER_CST);
3659   TREE_TYPE (null_node) = c_common_type_for_size (POINTER_SIZE, 0);
3660
3661   /* Since builtin_types isn't gc'ed, don't export these nodes.  */
3662   memset (builtin_types, 0, sizeof (builtin_types));
3663 }
3664
3665 /* Look up the function in built_in_decls that corresponds to DECL
3666    and set ASMSPEC as its user assembler name.  DECL must be a
3667    function decl that declares a builtin.  */
3668
3669 void
3670 set_builtin_user_assembler_name (tree decl, const char *asmspec)
3671 {
3672   tree builtin;
3673   gcc_assert (TREE_CODE (decl) == FUNCTION_DECL
3674               && DECL_BUILT_IN_CLASS (decl) == BUILT_IN_NORMAL
3675               && asmspec != 0);
3676
3677   builtin = built_in_decls [DECL_FUNCTION_CODE (decl)];
3678   set_user_assembler_name (builtin, asmspec);
3679   if (DECL_FUNCTION_CODE (decl) == BUILT_IN_MEMCPY)
3680     init_block_move_fn (asmspec);
3681   else if (DECL_FUNCTION_CODE (decl) == BUILT_IN_MEMSET)
3682     init_block_clear_fn (asmspec);
3683 }
3684
3685 /* The number of named compound-literals generated thus far.  */
3686 static GTY(()) int compound_literal_number;
3687
3688 /* Set DECL_NAME for DECL, a VAR_DECL for a compound-literal.  */
3689
3690 void
3691 set_compound_literal_name (tree decl)
3692 {
3693   char *name;
3694   ASM_FORMAT_PRIVATE_NAME (name, "__compound_literal",
3695                            compound_literal_number);
3696   compound_literal_number++;
3697   DECL_NAME (decl) = get_identifier (name);
3698 }
3699
3700 tree
3701 build_va_arg (tree expr, tree type)
3702 {
3703   return build1 (VA_ARG_EXPR, type, expr);
3704 }
3705
3706
3707 /* Linked list of disabled built-in functions.  */
3708
3709 typedef struct disabled_builtin
3710 {
3711   const char *name;
3712   struct disabled_builtin *next;
3713 } disabled_builtin;
3714 static disabled_builtin *disabled_builtins = NULL;
3715
3716 static bool builtin_function_disabled_p (const char *);
3717
3718 /* Disable a built-in function specified by -fno-builtin-NAME.  If NAME
3719    begins with "__builtin_", give an error.  */
3720
3721 void
3722 disable_builtin_function (const char *name)
3723 {
3724   if (strncmp (name, "__builtin_", strlen ("__builtin_")) == 0)
3725     error ("cannot disable built-in function %qs", name);
3726   else
3727     {
3728       disabled_builtin *new_disabled_builtin = XNEW (disabled_builtin);
3729       new_disabled_builtin->name = name;
3730       new_disabled_builtin->next = disabled_builtins;
3731       disabled_builtins = new_disabled_builtin;
3732     }
3733 }
3734
3735
3736 /* Return true if the built-in function NAME has been disabled, false
3737    otherwise.  */
3738
3739 static bool
3740 builtin_function_disabled_p (const char *name)
3741 {
3742   disabled_builtin *p;
3743   for (p = disabled_builtins; p != NULL; p = p->next)
3744     {
3745       if (strcmp (name, p->name) == 0)
3746         return true;
3747     }
3748   return false;
3749 }
3750
3751
3752 /* Worker for DEF_BUILTIN.
3753    Possibly define a builtin function with one or two names.
3754    Does not declare a non-__builtin_ function if flag_no_builtin, or if
3755    nonansi_p and flag_no_nonansi_builtin.  */
3756
3757 static void
3758 def_builtin_1 (enum built_in_function fncode,
3759                const char *name,
3760                enum built_in_class fnclass,
3761                tree fntype, tree libtype,
3762                bool both_p, bool fallback_p, bool nonansi_p,
3763                tree fnattrs, bool implicit_p)
3764 {
3765   tree decl;
3766   const char *libname;
3767
3768   if (fntype == error_mark_node)
3769     return;
3770
3771   gcc_assert ((!both_p && !fallback_p)
3772               || !strncmp (name, "__builtin_",
3773                            strlen ("__builtin_")));
3774
3775   libname = name + strlen ("__builtin_");
3776   decl = add_builtin_function (name, fntype, fncode, fnclass,
3777                                (fallback_p ? libname : NULL),
3778                                fnattrs);
3779   if (both_p
3780       && !flag_no_builtin && !builtin_function_disabled_p (libname)
3781       && !(nonansi_p && flag_no_nonansi_builtin))
3782     add_builtin_function (libname, libtype, fncode, fnclass,
3783                           NULL, fnattrs);
3784
3785   built_in_decls[(int) fncode] = decl;
3786   if (implicit_p)
3787     implicit_built_in_decls[(int) fncode] = decl;
3788 }
3789 \f
3790 /* Nonzero if the type T promotes to int.  This is (nearly) the
3791    integral promotions defined in ISO C99 6.3.1.1/2.  */
3792
3793 bool
3794 c_promoting_integer_type_p (tree t)
3795 {
3796   switch (TREE_CODE (t))
3797     {
3798     case INTEGER_TYPE:
3799       return (TYPE_MAIN_VARIANT (t) == char_type_node
3800               || TYPE_MAIN_VARIANT (t) == signed_char_type_node
3801               || TYPE_MAIN_VARIANT (t) == unsigned_char_type_node
3802               || TYPE_MAIN_VARIANT (t) == short_integer_type_node
3803               || TYPE_MAIN_VARIANT (t) == short_unsigned_type_node
3804               || TYPE_PRECISION (t) < TYPE_PRECISION (integer_type_node));
3805
3806     case ENUMERAL_TYPE:
3807       /* ??? Technically all enumerations not larger than an int
3808          promote to an int.  But this is used along code paths
3809          that only want to notice a size change.  */
3810       return TYPE_PRECISION (t) < TYPE_PRECISION (integer_type_node);
3811
3812     case BOOLEAN_TYPE:
3813       return 1;
3814
3815     default:
3816       return 0;
3817     }
3818 }
3819
3820 /* Return 1 if PARMS specifies a fixed number of parameters
3821    and none of their types is affected by default promotions.  */
3822
3823 int
3824 self_promoting_args_p (tree parms)
3825 {
3826   tree t;
3827   for (t = parms; t; t = TREE_CHAIN (t))
3828     {
3829       tree type = TREE_VALUE (t);
3830
3831       if (type == error_mark_node)
3832         continue;
3833
3834       if (TREE_CHAIN (t) == 0 && type != void_type_node)
3835         return 0;
3836
3837       if (type == 0)
3838         return 0;
3839
3840       if (TYPE_MAIN_VARIANT (type) == float_type_node)
3841         return 0;
3842
3843       if (c_promoting_integer_type_p (type))
3844         return 0;
3845     }
3846   return 1;
3847 }
3848
3849 /* Recursively examines the array elements of TYPE, until a non-array
3850    element type is found.  */
3851
3852 tree
3853 strip_array_types (tree type)
3854 {
3855   while (TREE_CODE (type) == ARRAY_TYPE)
3856     type = TREE_TYPE (type);
3857
3858   return type;
3859 }
3860
3861 /* Recursively remove any '*' or '&' operator from TYPE.  */
3862 tree
3863 strip_pointer_operator (tree t)
3864 {
3865   while (POINTER_TYPE_P (t))
3866     t = TREE_TYPE (t);
3867   return t;
3868 }
3869
3870 /* Used to compare case labels.  K1 and K2 are actually tree nodes
3871    representing case labels, or NULL_TREE for a `default' label.
3872    Returns -1 if K1 is ordered before K2, -1 if K1 is ordered after
3873    K2, and 0 if K1 and K2 are equal.  */
3874
3875 int
3876 case_compare (splay_tree_key k1, splay_tree_key k2)
3877 {
3878   /* Consider a NULL key (such as arises with a `default' label) to be
3879      smaller than anything else.  */
3880   if (!k1)
3881     return k2 ? -1 : 0;
3882   else if (!k2)
3883     return k1 ? 1 : 0;
3884
3885   return tree_int_cst_compare ((tree) k1, (tree) k2);
3886 }
3887
3888 /* Process a case label for the range LOW_VALUE ... HIGH_VALUE.  If
3889    LOW_VALUE and HIGH_VALUE are both NULL_TREE then this case label is
3890    actually a `default' label.  If only HIGH_VALUE is NULL_TREE, then
3891    case label was declared using the usual C/C++ syntax, rather than
3892    the GNU case range extension.  CASES is a tree containing all the
3893    case ranges processed so far; COND is the condition for the
3894    switch-statement itself.  Returns the CASE_LABEL_EXPR created, or
3895    ERROR_MARK_NODE if no CASE_LABEL_EXPR is created.  */
3896
3897 tree
3898 c_add_case_label (splay_tree cases, tree cond, tree orig_type,
3899                   tree low_value, tree high_value)
3900 {
3901   tree type;
3902   tree label;
3903   tree case_label;
3904   splay_tree_node node;
3905
3906   /* Create the LABEL_DECL itself.  */
3907   label = create_artificial_label ();
3908
3909   /* If there was an error processing the switch condition, bail now
3910      before we get more confused.  */
3911   if (!cond || cond == error_mark_node)
3912     goto error_out;
3913
3914   if ((low_value && TREE_TYPE (low_value)
3915        && POINTER_TYPE_P (TREE_TYPE (low_value)))
3916       || (high_value && TREE_TYPE (high_value)
3917           && POINTER_TYPE_P (TREE_TYPE (high_value))))
3918     {
3919       error ("pointers are not permitted as case values");
3920       goto error_out;
3921     }
3922
3923   /* Case ranges are a GNU extension.  */
3924   if (high_value && pedantic)
3925     pedwarn ("range expressions in switch statements are non-standard");
3926
3927   type = TREE_TYPE (cond);
3928   if (low_value)
3929     {
3930       low_value = check_case_value (low_value);
3931       low_value = convert_and_check (type, low_value);
3932       if (low_value == error_mark_node)
3933         goto error_out;
3934     }
3935   if (high_value)
3936     {
3937       high_value = check_case_value (high_value);
3938       high_value = convert_and_check (type, high_value);
3939       if (high_value == error_mark_node)
3940         goto error_out;
3941     }
3942
3943   if (low_value && high_value)
3944     {
3945       /* If the LOW_VALUE and HIGH_VALUE are the same, then this isn't
3946          really a case range, even though it was written that way.
3947          Remove the HIGH_VALUE to simplify later processing.  */
3948       if (tree_int_cst_equal (low_value, high_value))
3949         high_value = NULL_TREE;
3950       else if (!tree_int_cst_lt (low_value, high_value))
3951         warning (0, "empty range specified");
3952     }
3953
3954   /* See if the case is in range of the type of the original testing
3955      expression.  If both low_value and high_value are out of range,
3956      don't insert the case label and return NULL_TREE.  */
3957   if (low_value
3958       && !check_case_bounds (type, orig_type,
3959                              &low_value, high_value ? &high_value : NULL))
3960     return NULL_TREE;
3961
3962   /* Look up the LOW_VALUE in the table of case labels we already
3963      have.  */
3964   node = splay_tree_lookup (cases, (splay_tree_key) low_value);
3965   /* If there was not an exact match, check for overlapping ranges.
3966      There's no need to do this if there's no LOW_VALUE or HIGH_VALUE;
3967      that's a `default' label and the only overlap is an exact match.  */
3968   if (!node && (low_value || high_value))
3969     {
3970       splay_tree_node low_bound;
3971       splay_tree_node high_bound;
3972
3973       /* Even though there wasn't an exact match, there might be an
3974          overlap between this case range and another case range.
3975          Since we've (inductively) not allowed any overlapping case
3976          ranges, we simply need to find the greatest low case label
3977          that is smaller that LOW_VALUE, and the smallest low case
3978          label that is greater than LOW_VALUE.  If there is an overlap
3979          it will occur in one of these two ranges.  */
3980       low_bound = splay_tree_predecessor (cases,
3981                                           (splay_tree_key) low_value);
3982       high_bound = splay_tree_successor (cases,
3983                                          (splay_tree_key) low_value);
3984
3985       /* Check to see if the LOW_BOUND overlaps.  It is smaller than
3986          the LOW_VALUE, so there is no need to check unless the
3987          LOW_BOUND is in fact itself a case range.  */
3988       if (low_bound
3989           && CASE_HIGH ((tree) low_bound->value)
3990           && tree_int_cst_compare (CASE_HIGH ((tree) low_bound->value),
3991                                     low_value) >= 0)
3992         node = low_bound;
3993       /* Check to see if the HIGH_BOUND overlaps.  The low end of that
3994          range is bigger than the low end of the current range, so we
3995          are only interested if the current range is a real range, and
3996          not an ordinary case label.  */
3997       else if (high_bound
3998                && high_value
3999                && (tree_int_cst_compare ((tree) high_bound->key,
4000                                          high_value)
4001                    <= 0))
4002         node = high_bound;
4003     }
4004   /* If there was an overlap, issue an error.  */
4005   if (node)
4006     {
4007       tree duplicate = CASE_LABEL ((tree) node->value);
4008
4009       if (high_value)
4010         {
4011           error ("duplicate (or overlapping) case value");
4012           error ("%Jthis is the first entry overlapping that value", duplicate);
4013         }
4014       else if (low_value)
4015         {
4016           error ("duplicate case value") ;
4017           error ("%Jpreviously used here", duplicate);
4018         }
4019       else
4020         {
4021           error ("multiple default labels in one switch");
4022           error ("%Jthis is the first default label", duplicate);
4023         }
4024       goto error_out;
4025     }
4026
4027   /* Add a CASE_LABEL to the statement-tree.  */
4028   case_label = add_stmt (build_case_label (low_value, high_value, label));
4029   /* Register this case label in the splay tree.  */
4030   splay_tree_insert (cases,
4031                      (splay_tree_key) low_value,
4032                      (splay_tree_value) case_label);
4033
4034   return case_label;
4035
4036  error_out:
4037   /* Add a label so that the back-end doesn't think that the beginning of
4038      the switch is unreachable.  Note that we do not add a case label, as
4039      that just leads to duplicates and thence to failure later on.  */
4040   if (!cases->root)
4041     {
4042       tree t = create_artificial_label ();
4043       add_stmt (build_stmt (LABEL_EXPR, t));
4044     }
4045   return error_mark_node;
4046 }
4047
4048 /* Subroutines of c_do_switch_warnings, called via splay_tree_foreach.
4049    Used to verify that case values match up with enumerator values.  */
4050
4051 static void
4052 match_case_to_enum_1 (tree key, tree type, tree label)
4053 {
4054   char buf[2 + 2*HOST_BITS_PER_WIDE_INT/4 + 1];
4055
4056   /* ??? Not working too hard to print the double-word value.
4057      Should perhaps be done with %lwd in the diagnostic routines?  */
4058   if (TREE_INT_CST_HIGH (key) == 0)
4059     snprintf (buf, sizeof (buf), HOST_WIDE_INT_PRINT_UNSIGNED,
4060               TREE_INT_CST_LOW (key));
4061   else if (!TYPE_UNSIGNED (type)
4062            && TREE_INT_CST_HIGH (key) == -1
4063            && TREE_INT_CST_LOW (key) != 0)
4064     snprintf (buf, sizeof (buf), "-" HOST_WIDE_INT_PRINT_UNSIGNED,
4065               -TREE_INT_CST_LOW (key));
4066   else
4067     snprintf (buf, sizeof (buf), HOST_WIDE_INT_PRINT_DOUBLE_HEX,
4068               TREE_INT_CST_HIGH (key), TREE_INT_CST_LOW (key));
4069
4070   if (TYPE_NAME (type) == 0)
4071     warning (0, "%Jcase value %qs not in enumerated type",
4072              CASE_LABEL (label), buf);
4073   else
4074     warning (0, "%Jcase value %qs not in enumerated type %qT",
4075              CASE_LABEL (label), buf, type);
4076 }
4077
4078 /* Subroutine of c_do_switch_warnings, called via splay_tree_foreach.
4079    Used to verify that case values match up with enumerator values.  */
4080
4081 static int
4082 match_case_to_enum (splay_tree_node node, void *data)
4083 {
4084   tree label = (tree) node->value;
4085   tree type = (tree) data;
4086
4087   /* Skip default case.  */
4088   if (!CASE_LOW (label))
4089     return 0;
4090
4091   /* If CASE_LOW_SEEN is not set, that means CASE_LOW did not appear
4092      when we did our enum->case scan.  Reset our scratch bit after.  */
4093   if (!CASE_LOW_SEEN (label))
4094     match_case_to_enum_1 (CASE_LOW (label), type, label);
4095   else
4096     CASE_LOW_SEEN (label) = 0;
4097
4098   /* If CASE_HIGH is non-null, we have a range.  If CASE_HIGH_SEEN is
4099      not set, that means that CASE_HIGH did not appear when we did our
4100      enum->case scan.  Reset our scratch bit after.  */
4101   if (CASE_HIGH (label))
4102     {
4103       if (!CASE_HIGH_SEEN (label))
4104         match_case_to_enum_1 (CASE_HIGH (label), type, label);
4105       else
4106         CASE_HIGH_SEEN (label) = 0;
4107     }
4108
4109   return 0;
4110 }
4111
4112 /* Handle -Wswitch*.  Called from the front end after parsing the
4113    switch construct.  */
4114 /* ??? Should probably be somewhere generic, since other languages
4115    besides C and C++ would want this.  At the moment, however, C/C++
4116    are the only tree-ssa languages that support enumerations at all,
4117    so the point is moot.  */
4118
4119 void
4120 c_do_switch_warnings (splay_tree cases, location_t switch_location,
4121                       tree type, tree cond)
4122 {
4123   splay_tree_node default_node;
4124   splay_tree_node node;
4125   tree chain;
4126
4127   if (!warn_switch && !warn_switch_enum && !warn_switch_default)
4128     return;
4129
4130   default_node = splay_tree_lookup (cases, (splay_tree_key) NULL);
4131   if (!default_node)
4132     warning (OPT_Wswitch_default, "%Hswitch missing default case",
4133              &switch_location);
4134
4135   /* From here on, we only care about about enumerated types.  */
4136   if (!type || TREE_CODE (type) != ENUMERAL_TYPE)
4137     return;
4138
4139   /* If the switch expression was an enumerated type, check that
4140      exactly all enumeration literals are covered by the cases.
4141      The check is made when -Wswitch was specified and there is no
4142      default case, or when -Wswitch-enum was specified.  */
4143
4144   if (!warn_switch_enum
4145       && !(warn_switch && !default_node))
4146     return;
4147
4148   /* Clearing COND if it is not an integer constant simplifies
4149      the tests inside the loop below.  */
4150   if (TREE_CODE (cond) != INTEGER_CST)
4151     cond = NULL_TREE;
4152
4153   /* The time complexity here is O(N*lg(N)) worst case, but for the
4154       common case of monotonically increasing enumerators, it is
4155       O(N), since the nature of the splay tree will keep the next
4156       element adjacent to the root at all times.  */
4157
4158   for (chain = TYPE_VALUES (type); chain; chain = TREE_CHAIN (chain))
4159     {
4160       tree value = TREE_VALUE (chain);
4161       node = splay_tree_lookup (cases, (splay_tree_key) value);
4162       if (node)
4163         {
4164           /* Mark the CASE_LOW part of the case entry as seen.  */
4165           tree label = (tree) node->value;
4166           CASE_LOW_SEEN (label) = 1;
4167           continue;
4168         }
4169
4170       /* Even though there wasn't an exact match, there might be a
4171          case range which includes the enumator's value.  */
4172       node = splay_tree_predecessor (cases, (splay_tree_key) value);
4173       if (node && CASE_HIGH ((tree) node->value))
4174         {
4175           tree label = (tree) node->value;
4176           int cmp = tree_int_cst_compare (CASE_HIGH (label), value);
4177           if (cmp >= 0)
4178             {
4179               /* If we match the upper bound exactly, mark the CASE_HIGH
4180                  part of the case entry as seen.  */
4181               if (cmp == 0)
4182                 CASE_HIGH_SEEN (label) = 1;
4183               continue;
4184             }
4185         }
4186
4187       /* We've now determined that this enumerated literal isn't
4188          handled by the case labels of the switch statement.  */
4189
4190       /* If the switch expression is a constant, we only really care
4191          about whether that constant is handled by the switch.  */
4192       if (cond && tree_int_cst_compare (cond, value))
4193         continue;
4194
4195       warning (0, "%Henumeration value %qE not handled in switch",
4196                &switch_location, TREE_PURPOSE (chain));
4197     }
4198
4199   /* Warn if there are case expressions that don't correspond to
4200      enumerators.  This can occur since C and C++ don't enforce
4201      type-checking of assignments to enumeration variables.
4202
4203      The time complexity here is now always O(N) worst case, since
4204      we should have marked both the lower bound and upper bound of
4205      every disjoint case label, with CASE_LOW_SEEN and CASE_HIGH_SEEN
4206      above.  This scan also resets those fields.  */
4207   splay_tree_foreach (cases, match_case_to_enum, type);
4208 }
4209
4210 /* Finish an expression taking the address of LABEL (an
4211    IDENTIFIER_NODE).  Returns an expression for the address.  */
4212
4213 tree
4214 finish_label_address_expr (tree label)
4215 {
4216   tree result;
4217
4218   if (pedantic)
4219     pedwarn ("taking the address of a label is non-standard");
4220
4221   if (label == error_mark_node)
4222     return error_mark_node;
4223
4224   label = lookup_label (label);
4225   if (label == NULL_TREE)
4226     result = null_pointer_node;
4227   else
4228     {
4229       TREE_USED (label) = 1;
4230       result = build1 (ADDR_EXPR, ptr_type_node, label);
4231       /* The current function in not necessarily uninlinable.
4232          Computed gotos are incompatible with inlining, but the value
4233          here could be used only in a diagnostic, for example.  */
4234     }
4235
4236   return result;
4237 }
4238
4239 /* Hook used by expand_expr to expand language-specific tree codes.  */
4240 /* The only things that should go here are bits needed to expand
4241    constant initializers.  Everything else should be handled by the
4242    gimplification routines.  */
4243
4244 rtx
4245 c_expand_expr (tree exp, rtx target, enum machine_mode tmode,
4246                int modifier /* Actually enum_modifier.  */,
4247                rtx *alt_rtl)
4248 {
4249   switch (TREE_CODE (exp))
4250     {
4251     case COMPOUND_LITERAL_EXPR:
4252       {
4253         /* Initialize the anonymous variable declared in the compound
4254            literal, then return the variable.  */
4255         tree decl = COMPOUND_LITERAL_EXPR_DECL (exp);
4256         emit_local_var (decl);
4257         return expand_expr_real (decl, target, tmode, modifier, alt_rtl);
4258       }
4259
4260     default:
4261       gcc_unreachable ();
4262     }
4263 }
4264
4265
4266 /* Generate the RTL for the body of FNDECL.  */
4267
4268 void
4269 c_expand_body (tree fndecl)
4270 {
4271
4272   if (!DECL_INITIAL (fndecl)
4273       || DECL_INITIAL (fndecl) == error_mark_node)
4274     return;
4275
4276   tree_rest_of_compilation (fndecl);
4277
4278   if (DECL_STATIC_CONSTRUCTOR (fndecl)
4279       && targetm.have_ctors_dtors)
4280     targetm.asm_out.constructor (XEXP (DECL_RTL (fndecl), 0),
4281                                  decl_init_priority_lookup (fndecl));
4282   if (DECL_STATIC_DESTRUCTOR (fndecl)
4283       && targetm.have_ctors_dtors)
4284     targetm.asm_out.destructor (XEXP (DECL_RTL (fndecl), 0),
4285                                 decl_fini_priority_lookup (fndecl));
4286 }
4287
4288 /* Hook used by staticp to handle language-specific tree codes.  */
4289
4290 tree
4291 c_staticp (tree exp)
4292 {
4293   return (TREE_CODE (exp) == COMPOUND_LITERAL_EXPR
4294           && TREE_STATIC (COMPOUND_LITERAL_EXPR_DECL (exp))
4295           ? exp : NULL);
4296 }
4297 \f
4298
4299 /* Given a boolean expression ARG, return a tree representing an increment
4300    or decrement (as indicated by CODE) of ARG.  The front end must check for
4301    invalid cases (e.g., decrement in C++).  */
4302 tree
4303 boolean_increment (enum tree_code code, tree arg)
4304 {
4305   tree val;
4306   tree true_res = boolean_true_node;
4307
4308   arg = stabilize_reference (arg);
4309   switch (code)
4310     {
4311     case PREINCREMENT_EXPR:
4312       val = build2 (MODIFY_EXPR, TREE_TYPE (arg), arg, true_res);
4313       break;
4314     case POSTINCREMENT_EXPR:
4315       val = build2 (MODIFY_EXPR, TREE_TYPE (arg), arg, true_res);
4316       arg = save_expr (arg);
4317       val = build2 (COMPOUND_EXPR, TREE_TYPE (arg), val, arg);
4318       val = build2 (COMPOUND_EXPR, TREE_TYPE (arg), arg, val);
4319       break;
4320     case PREDECREMENT_EXPR:
4321       val = build2 (MODIFY_EXPR, TREE_TYPE (arg), arg,
4322                     invert_truthvalue (arg));
4323       break;
4324     case POSTDECREMENT_EXPR:
4325       val = build2 (MODIFY_EXPR, TREE_TYPE (arg), arg,
4326                     invert_truthvalue (arg));
4327       arg = save_expr (arg);
4328       val = build2 (COMPOUND_EXPR, TREE_TYPE (arg), val, arg);
4329       val = build2 (COMPOUND_EXPR, TREE_TYPE (arg), arg, val);
4330       break;
4331     default:
4332       gcc_unreachable ();
4333     }
4334   TREE_SIDE_EFFECTS (val) = 1;
4335   return val;
4336 }
4337 \f
4338 /* Built-in macros for stddef.h, that require macros defined in this
4339    file.  */
4340 void
4341 c_stddef_cpp_builtins(void)
4342 {
4343   builtin_define_with_value ("__SIZE_TYPE__", SIZE_TYPE, 0);
4344   builtin_define_with_value ("__PTRDIFF_TYPE__", PTRDIFF_TYPE, 0);
4345   builtin_define_with_value ("__WCHAR_TYPE__", MODIFIED_WCHAR_TYPE, 0);
4346   builtin_define_with_value ("__WINT_TYPE__", WINT_TYPE, 0);
4347   builtin_define_with_value ("__INTMAX_TYPE__", INTMAX_TYPE, 0);
4348   builtin_define_with_value ("__UINTMAX_TYPE__", UINTMAX_TYPE, 0);
4349 }
4350
4351 static void
4352 c_init_attributes (void)
4353 {
4354   /* Fill in the built_in_attributes array.  */
4355 #define DEF_ATTR_NULL_TREE(ENUM)                                \
4356   built_in_attributes[(int) ENUM] = NULL_TREE;
4357 #define DEF_ATTR_INT(ENUM, VALUE)                               \
4358   built_in_attributes[(int) ENUM] = build_int_cst (NULL_TREE, VALUE);
4359 #define DEF_ATTR_IDENT(ENUM, STRING)                            \
4360   built_in_attributes[(int) ENUM] = get_identifier (STRING);
4361 #define DEF_ATTR_TREE_LIST(ENUM, PURPOSE, VALUE, CHAIN) \
4362   built_in_attributes[(int) ENUM]                       \
4363     = tree_cons (built_in_attributes[(int) PURPOSE],    \
4364                  built_in_attributes[(int) VALUE],      \
4365                  built_in_attributes[(int) CHAIN]);
4366 #include "builtin-attrs.def"
4367 #undef DEF_ATTR_NULL_TREE
4368 #undef DEF_ATTR_INT
4369 #undef DEF_ATTR_IDENT
4370 #undef DEF_ATTR_TREE_LIST
4371 }
4372
4373 /* Attribute handlers common to C front ends.  */
4374
4375 /* Handle a "packed" attribute; arguments as in
4376    struct attribute_spec.handler.  */
4377
4378 static tree
4379 handle_packed_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4380                          int flags, bool *no_add_attrs)
4381 {
4382   if (TYPE_P (*node))
4383     {
4384       if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
4385         *node = build_variant_type_copy (*node);
4386       TYPE_PACKED (*node) = 1;
4387     }
4388   else if (TREE_CODE (*node) == FIELD_DECL)
4389     {
4390       if (TYPE_ALIGN (TREE_TYPE (*node)) <= BITS_PER_UNIT)
4391         warning (OPT_Wattributes,
4392                  "%qE attribute ignored for field of type %qT",
4393                  name, TREE_TYPE (*node));
4394       else
4395         DECL_PACKED (*node) = 1;
4396     }
4397   /* We can't set DECL_PACKED for a VAR_DECL, because the bit is
4398      used for DECL_REGISTER.  It wouldn't mean anything anyway.
4399      We can't set DECL_PACKED on the type of a TYPE_DECL, because
4400      that changes what the typedef is typing.  */
4401   else
4402     {
4403       warning (OPT_Wattributes, "%qE attribute ignored", name);
4404       *no_add_attrs = true;
4405     }
4406
4407   return NULL_TREE;
4408 }
4409
4410 /* Handle a "nocommon" attribute; arguments as in
4411    struct attribute_spec.handler.  */
4412
4413 static tree
4414 handle_nocommon_attribute (tree *node, tree name,
4415                            tree ARG_UNUSED (args),
4416                            int ARG_UNUSED (flags), bool *no_add_attrs)
4417 {
4418   if (TREE_CODE (*node) == VAR_DECL)
4419     DECL_COMMON (*node) = 0;
4420   else
4421     {
4422       warning (OPT_Wattributes, "%qE attribute ignored", name);
4423       *no_add_attrs = true;
4424     }
4425
4426   return NULL_TREE;
4427 }
4428
4429 /* Handle a "common" attribute; arguments as in
4430    struct attribute_spec.handler.  */
4431
4432 static tree
4433 handle_common_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4434                          int ARG_UNUSED (flags), bool *no_add_attrs)
4435 {
4436   if (TREE_CODE (*node) == VAR_DECL)
4437     DECL_COMMON (*node) = 1;
4438   else
4439     {
4440       warning (OPT_Wattributes, "%qE attribute ignored", name);
4441       *no_add_attrs = true;
4442     }
4443
4444   return NULL_TREE;
4445 }
4446
4447 /* Handle a "noreturn" attribute; arguments as in
4448    struct attribute_spec.handler.  */
4449
4450 static tree
4451 handle_noreturn_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4452                            int ARG_UNUSED (flags), bool *no_add_attrs)
4453 {
4454   tree type = TREE_TYPE (*node);
4455
4456   /* See FIXME comment in c_common_attribute_table.  */
4457   if (TREE_CODE (*node) == FUNCTION_DECL)
4458     TREE_THIS_VOLATILE (*node) = 1;
4459   else if (TREE_CODE (type) == POINTER_TYPE
4460            && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE)
4461     TREE_TYPE (*node)
4462       = build_pointer_type
4463         (build_type_variant (TREE_TYPE (type),
4464                              TYPE_READONLY (TREE_TYPE (type)), 1));
4465   else
4466     {
4467       warning (OPT_Wattributes, "%qE attribute ignored", name);
4468       *no_add_attrs = true;
4469     }
4470
4471   return NULL_TREE;
4472 }
4473
4474 /* Handle a "hot" and attribute; arguments as in
4475    struct attribute_spec.handler.  */
4476
4477 static tree
4478 handle_hot_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4479                           int ARG_UNUSED (flags), bool *no_add_attrs)
4480 {
4481   if (TREE_CODE (*node) == FUNCTION_DECL)
4482     {
4483       if (lookup_attribute ("cold", DECL_ATTRIBUTES (*node)) != NULL)
4484         {
4485           warning (OPT_Wattributes, "%qE attribute conflicts with attribute %s",
4486                    name, "cold");
4487           *no_add_attrs = true;
4488         }
4489       /* Do nothing else, just set the attribute.  We'll get at
4490          it later with lookup_attribute.  */
4491     }
4492   else
4493     {
4494       warning (OPT_Wattributes, "%qE attribute ignored", name);
4495       *no_add_attrs = true;
4496     }
4497
4498   return NULL_TREE;
4499 }
4500 /* Handle a "cold" and attribute; arguments as in
4501    struct attribute_spec.handler.  */
4502
4503 static tree
4504 handle_cold_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4505                        int ARG_UNUSED (flags), bool *no_add_attrs)
4506 {
4507   if (TREE_CODE (*node) == FUNCTION_DECL)
4508     {
4509       if (lookup_attribute ("hot", DECL_ATTRIBUTES (*node)) != NULL)
4510         {
4511           warning (OPT_Wattributes, "%qE attribute conflicts with attribute %s",
4512                    name, "hot");
4513           *no_add_attrs = true;
4514         }
4515       /* Do nothing else, just set the attribute.  We'll get at
4516          it later with lookup_attribute.  */
4517     }
4518   else
4519     {
4520       warning (OPT_Wattributes, "%qE attribute ignored", name);
4521       *no_add_attrs = true;
4522     }
4523
4524   return NULL_TREE;
4525 }
4526
4527 /* Handle a "noinline" attribute; arguments as in
4528    struct attribute_spec.handler.  */
4529
4530 static tree
4531 handle_noinline_attribute (tree *node, tree name,
4532                            tree ARG_UNUSED (args),
4533                            int ARG_UNUSED (flags), bool *no_add_attrs)
4534 {
4535   if (TREE_CODE (*node) == FUNCTION_DECL)
4536     DECL_UNINLINABLE (*node) = 1;
4537   else
4538     {
4539       warning (OPT_Wattributes, "%qE attribute ignored", name);
4540       *no_add_attrs = true;
4541     }
4542
4543   return NULL_TREE;
4544 }
4545
4546 /* Handle a "always_inline" attribute; arguments as in
4547    struct attribute_spec.handler.  */
4548
4549 static tree
4550 handle_always_inline_attribute (tree *node, tree name,
4551                                 tree ARG_UNUSED (args),
4552                                 int ARG_UNUSED (flags),
4553                                 bool *no_add_attrs)
4554 {
4555   if (TREE_CODE (*node) == FUNCTION_DECL)
4556     {
4557       /* Do nothing else, just set the attribute.  We'll get at
4558          it later with lookup_attribute.  */
4559     }
4560   else
4561     {
4562       warning (OPT_Wattributes, "%qE attribute ignored", name);
4563       *no_add_attrs = true;
4564     }
4565
4566   return NULL_TREE;
4567 }
4568
4569 /* Handle a "gnu_inline" attribute; arguments as in
4570    struct attribute_spec.handler.  */
4571
4572 static tree
4573 handle_gnu_inline_attribute (tree *node, tree name,
4574                              tree ARG_UNUSED (args),
4575                              int ARG_UNUSED (flags),
4576                              bool *no_add_attrs)
4577 {
4578   if (TREE_CODE (*node) == FUNCTION_DECL && DECL_DECLARED_INLINE_P (*node))
4579     {
4580       /* Do nothing else, just set the attribute.  We'll get at
4581          it later with lookup_attribute.  */
4582     }
4583   else
4584     {
4585       warning (OPT_Wattributes, "%qE attribute ignored", name);
4586       *no_add_attrs = true;
4587     }
4588
4589   return NULL_TREE;
4590 }
4591
4592 /* Handle a "flatten" attribute; arguments as in
4593    struct attribute_spec.handler.  */
4594
4595 static tree
4596 handle_flatten_attribute (tree *node, tree name,
4597                           tree args ATTRIBUTE_UNUSED,
4598                           int flags ATTRIBUTE_UNUSED, bool *no_add_attrs)
4599 {
4600   if (TREE_CODE (*node) == FUNCTION_DECL)
4601     /* Do nothing else, just set the attribute.  We'll get at
4602        it later with lookup_attribute.  */
4603     ;
4604   else
4605     {
4606       warning (OPT_Wattributes, "%qE attribute ignored", name);
4607       *no_add_attrs = true;
4608     }
4609
4610   return NULL_TREE;
4611 }
4612
4613
4614 /* Handle a "used" attribute; arguments as in
4615    struct attribute_spec.handler.  */
4616
4617 static tree
4618 handle_used_attribute (tree *pnode, tree name, tree ARG_UNUSED (args),
4619                        int ARG_UNUSED (flags), bool *no_add_attrs)
4620 {
4621   tree node = *pnode;
4622
4623   if (TREE_CODE (node) == FUNCTION_DECL
4624       || (TREE_CODE (node) == VAR_DECL && TREE_STATIC (node)))
4625     {
4626       TREE_USED (node) = 1;
4627       DECL_PRESERVE_P (node) = 1;
4628     }
4629   else
4630     {
4631       warning (OPT_Wattributes, "%qE attribute ignored", name);
4632       *no_add_attrs = true;
4633     }
4634
4635   return NULL_TREE;
4636 }
4637
4638 /* Handle a "unused" attribute; arguments as in
4639    struct attribute_spec.handler.  */
4640
4641 static tree
4642 handle_unused_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4643                          int flags, bool *no_add_attrs)
4644 {
4645   if (DECL_P (*node))
4646     {
4647       tree decl = *node;
4648
4649       if (TREE_CODE (decl) == PARM_DECL
4650           || TREE_CODE (decl) == VAR_DECL
4651           || TREE_CODE (decl) == FUNCTION_DECL
4652           || TREE_CODE (decl) == LABEL_DECL
4653           || TREE_CODE (decl) == TYPE_DECL)
4654         TREE_USED (decl) = 1;
4655       else
4656         {
4657           warning (OPT_Wattributes, "%qE attribute ignored", name);
4658           *no_add_attrs = true;
4659         }
4660     }
4661   else
4662     {
4663       if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
4664         *node = build_variant_type_copy (*node);
4665       TREE_USED (*node) = 1;
4666     }
4667
4668   return NULL_TREE;
4669 }
4670
4671 /* Handle a "externally_visible" attribute; arguments as in
4672    struct attribute_spec.handler.  */
4673
4674 static tree
4675 handle_externally_visible_attribute (tree *pnode, tree name,
4676                                      tree ARG_UNUSED (args),
4677                                      int ARG_UNUSED (flags),
4678                                      bool *no_add_attrs)
4679 {
4680   tree node = *pnode;
4681
4682   if (TREE_CODE (node) == FUNCTION_DECL || TREE_CODE (node) == VAR_DECL)
4683     {
4684       if ((!TREE_STATIC (node) && TREE_CODE (node) != FUNCTION_DECL
4685            && !DECL_EXTERNAL (node)) || !TREE_PUBLIC (node))
4686         {
4687           warning (OPT_Wattributes,
4688                    "%qE attribute have effect only on public objects", name);
4689           *no_add_attrs = true;
4690         }
4691     }
4692   else
4693     {
4694       warning (OPT_Wattributes, "%qE attribute ignored", name);
4695       *no_add_attrs = true;
4696     }
4697
4698   return NULL_TREE;
4699 }
4700
4701 /* Handle a "const" attribute; arguments as in
4702    struct attribute_spec.handler.  */
4703
4704 static tree
4705 handle_const_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4706                         int ARG_UNUSED (flags), bool *no_add_attrs)
4707 {
4708   tree type = TREE_TYPE (*node);
4709
4710   /* See FIXME comment on noreturn in c_common_attribute_table.  */
4711   if (TREE_CODE (*node) == FUNCTION_DECL)
4712     TREE_READONLY (*node) = 1;
4713   else if (TREE_CODE (type) == POINTER_TYPE
4714            && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE)
4715     TREE_TYPE (*node)
4716       = build_pointer_type
4717         (build_type_variant (TREE_TYPE (type), 1,
4718                              TREE_THIS_VOLATILE (TREE_TYPE (type))));
4719   else
4720     {
4721       warning (OPT_Wattributes, "%qE attribute ignored", name);
4722       *no_add_attrs = true;
4723     }
4724
4725   return NULL_TREE;
4726 }
4727
4728 /* Handle a "transparent_union" attribute; arguments as in
4729    struct attribute_spec.handler.  */
4730
4731 static tree
4732 handle_transparent_union_attribute (tree *node, tree name,
4733                                     tree ARG_UNUSED (args), int flags,
4734                                     bool *no_add_attrs)
4735 {
4736   tree type = NULL;
4737
4738   *no_add_attrs = true;
4739
4740   if (DECL_P (*node))
4741     {
4742       if (TREE_CODE (*node) != TYPE_DECL)
4743         goto ignored;
4744       node = &TREE_TYPE (*node);
4745       type = *node;
4746     }
4747   else if (TYPE_P (*node))
4748     type = *node;
4749   else
4750     goto ignored;
4751
4752   if (TREE_CODE (type) == UNION_TYPE)
4753     {
4754       /* When IN_PLACE is set, leave the check for FIELDS and MODE to
4755          the code in finish_struct.  */
4756       if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
4757         {
4758           if (TYPE_FIELDS (type) == NULL_TREE
4759               || TYPE_MODE (type) != DECL_MODE (TYPE_FIELDS (type)))
4760             goto ignored;
4761
4762           /* A type variant isn't good enough, since we don't a cast
4763              to such a type removed as a no-op.  */
4764           *node = type = build_duplicate_type (type);
4765         }
4766
4767       TYPE_TRANSPARENT_UNION (type) = 1;
4768       return NULL_TREE;
4769     }
4770
4771  ignored:
4772   warning (OPT_Wattributes, "%qE attribute ignored", name);
4773   return NULL_TREE;
4774 }
4775
4776 /* Subroutine of handle_{con,de}structor_attribute.  Evaluate ARGS to
4777    get the requested priority for a constructor or destructor,
4778    possibly issuing diagnostics for invalid or reserved
4779    priorities.  */
4780
4781 static priority_type
4782 get_priority (tree args, bool is_destructor)
4783 {
4784   HOST_WIDE_INT pri;
4785   tree arg;
4786
4787   if (!args)
4788     return DEFAULT_INIT_PRIORITY;
4789
4790   if (!SUPPORTS_INIT_PRIORITY)
4791     {
4792       if (is_destructor)
4793         error ("destructor priorities are not supported");
4794       else
4795         error ("constructor priorities are not supported");
4796       return DEFAULT_INIT_PRIORITY;
4797     }
4798
4799   arg = TREE_VALUE (args);
4800   if (!host_integerp (arg, /*pos=*/0)
4801       || !INTEGRAL_TYPE_P (TREE_TYPE (arg)))
4802     goto invalid;
4803
4804   pri = tree_low_cst (TREE_VALUE (args), /*pos=*/0);
4805   if (pri < 0 || pri > MAX_INIT_PRIORITY)
4806     goto invalid;
4807
4808   if (pri <= MAX_RESERVED_INIT_PRIORITY)
4809     {
4810       if (is_destructor)
4811         warning (0,
4812                  "destructor priorities from 0 to %d are reserved "
4813                  "for the implementation",
4814                  MAX_RESERVED_INIT_PRIORITY);
4815       else
4816         warning (0,
4817                  "constructor priorities from 0 to %d are reserved "
4818                  "for the implementation",
4819                  MAX_RESERVED_INIT_PRIORITY);
4820     }
4821   return pri;
4822
4823  invalid:
4824   if (is_destructor)
4825     error ("destructor priorities must be integers from 0 to %d inclusive",
4826            MAX_INIT_PRIORITY);
4827   else
4828     error ("constructor priorities must be integers from 0 to %d inclusive",
4829            MAX_INIT_PRIORITY);
4830   return DEFAULT_INIT_PRIORITY;
4831 }
4832
4833 /* Handle a "constructor" attribute; arguments as in
4834    struct attribute_spec.handler.  */
4835
4836 static tree
4837 handle_constructor_attribute (tree *node, tree name, tree args,
4838                               int ARG_UNUSED (flags),
4839                               bool *no_add_attrs)
4840 {
4841   tree decl = *node;
4842   tree type = TREE_TYPE (decl);
4843
4844   if (TREE_CODE (decl) == FUNCTION_DECL
4845       && TREE_CODE (type) == FUNCTION_TYPE
4846       && decl_function_context (decl) == 0)
4847     {
4848       priority_type priority;
4849       DECL_STATIC_CONSTRUCTOR (decl) = 1;
4850       priority = get_priority (args, /*is_destructor=*/false);
4851       SET_DECL_INIT_PRIORITY (decl, priority);
4852       TREE_USED (decl) = 1;
4853     }
4854   else
4855     {
4856       warning (OPT_Wattributes, "%qE attribute ignored", name);
4857       *no_add_attrs = true;
4858     }
4859
4860   return NULL_TREE;
4861 }
4862
4863 /* Handle a "destructor" attribute; arguments as in
4864    struct attribute_spec.handler.  */
4865
4866 static tree
4867 handle_destructor_attribute (tree *node, tree name, tree args,
4868                              int ARG_UNUSED (flags),
4869                              bool *no_add_attrs)
4870 {
4871   tree decl = *node;
4872   tree type = TREE_TYPE (decl);
4873
4874   if (TREE_CODE (decl) == FUNCTION_DECL
4875       && TREE_CODE (type) == FUNCTION_TYPE
4876       && decl_function_context (decl) == 0)
4877     {
4878       priority_type priority;
4879       DECL_STATIC_DESTRUCTOR (decl) = 1;
4880       priority = get_priority (args, /*is_destructor=*/true);
4881       SET_DECL_FINI_PRIORITY (decl, priority);
4882       TREE_USED (decl) = 1;
4883     }
4884   else
4885     {
4886       warning (OPT_Wattributes, "%qE attribute ignored", name);
4887       *no_add_attrs = true;
4888     }
4889
4890   return NULL_TREE;
4891 }
4892
4893 /* Handle a "mode" attribute; arguments as in
4894    struct attribute_spec.handler.  */
4895
4896 static tree
4897 handle_mode_attribute (tree *node, tree name, tree args,
4898                        int ARG_UNUSED (flags), bool *no_add_attrs)
4899 {
4900   tree type = *node;
4901
4902   *no_add_attrs = true;
4903
4904   if (TREE_CODE (TREE_VALUE (args)) != IDENTIFIER_NODE)
4905     warning (OPT_Wattributes, "%qE attribute ignored", name);
4906   else
4907     {
4908       int j;
4909       const char *p = IDENTIFIER_POINTER (TREE_VALUE (args));
4910       int len = strlen (p);
4911       enum machine_mode mode = VOIDmode;
4912       tree typefm;
4913       bool valid_mode;
4914
4915       if (len > 4 && p[0] == '_' && p[1] == '_'
4916           && p[len - 1] == '_' && p[len - 2] == '_')
4917         {
4918           char *newp = (char *) alloca (len - 1);
4919
4920           strcpy (newp, &p[2]);
4921           newp[len - 4] = '\0';
4922           p = newp;
4923         }
4924
4925       /* Change this type to have a type with the specified mode.
4926          First check for the special modes.  */
4927       if (!strcmp (p, "byte"))
4928         mode = byte_mode;
4929       else if (!strcmp (p, "word"))
4930         mode = word_mode;
4931       else if (!strcmp (p, "pointer"))
4932         mode = ptr_mode;
4933       else
4934         for (j = 0; j < NUM_MACHINE_MODES; j++)
4935           if (!strcmp (p, GET_MODE_NAME (j)))
4936             {
4937               mode = (enum machine_mode) j;
4938               break;
4939             }
4940
4941       if (mode == VOIDmode)
4942         {
4943           error ("unknown machine mode %qs", p);
4944           return NULL_TREE;
4945         }
4946
4947       valid_mode = false;
4948       switch (GET_MODE_CLASS (mode))
4949         {
4950         case MODE_INT:
4951         case MODE_PARTIAL_INT:
4952         case MODE_FLOAT:
4953         case MODE_DECIMAL_FLOAT:
4954           valid_mode = targetm.scalar_mode_supported_p (mode);
4955           break;
4956
4957         case MODE_COMPLEX_INT:
4958         case MODE_COMPLEX_FLOAT:
4959           valid_mode = targetm.scalar_mode_supported_p (GET_MODE_INNER (mode));
4960           break;
4961
4962         case MODE_VECTOR_INT:
4963         case MODE_VECTOR_FLOAT:
4964           warning (OPT_Wattributes, "specifying vector types with "
4965                    "__attribute__ ((mode)) is deprecated");
4966           warning (OPT_Wattributes,
4967                    "use __attribute__ ((vector_size)) instead");
4968           valid_mode = vector_mode_valid_p (mode);
4969           break;
4970
4971         default:
4972           break;
4973         }
4974       if (!valid_mode)
4975         {
4976           error ("unable to emulate %qs", p);
4977           return NULL_TREE;
4978         }
4979
4980       if (POINTER_TYPE_P (type))
4981         {
4982           tree (*fn)(tree, enum machine_mode, bool);
4983
4984           if (!targetm.valid_pointer_mode (mode))
4985             {
4986               error ("invalid pointer mode %qs", p);
4987               return NULL_TREE;
4988             }
4989
4990           if (TREE_CODE (type) == POINTER_TYPE)
4991             fn = build_pointer_type_for_mode;
4992           else
4993             fn = build_reference_type_for_mode;
4994           typefm = fn (TREE_TYPE (type), mode, false);
4995         }
4996       else
4997         typefm = lang_hooks.types.type_for_mode (mode, TYPE_UNSIGNED (type));
4998
4999       if (typefm == NULL_TREE)
5000         {
5001           error ("no data type for mode %qs", p);
5002           return NULL_TREE;
5003         }
5004       else if (TREE_CODE (type) == ENUMERAL_TYPE)
5005         {
5006           /* For enumeral types, copy the precision from the integer
5007              type returned above.  If not an INTEGER_TYPE, we can't use
5008              this mode for this type.  */
5009           if (TREE_CODE (typefm) != INTEGER_TYPE)
5010             {
5011               error ("cannot use mode %qs for enumeral types", p);
5012               return NULL_TREE;
5013             }
5014
5015           if (flags & ATTR_FLAG_TYPE_IN_PLACE)
5016             {
5017               TYPE_PRECISION (type) = TYPE_PRECISION (typefm);
5018               typefm = type;
5019             }
5020           else
5021             {
5022               /* We cannot build a type variant, as there's code that assumes
5023                  that TYPE_MAIN_VARIANT has the same mode.  This includes the
5024                  debug generators.  Instead, create a subrange type.  This
5025                  results in all of the enumeral values being emitted only once
5026                  in the original, and the subtype gets them by reference.  */
5027               if (TYPE_UNSIGNED (type))
5028                 typefm = make_unsigned_type (TYPE_PRECISION (typefm));
5029               else
5030                 typefm = make_signed_type (TYPE_PRECISION (typefm));
5031               TREE_TYPE (typefm) = type;
5032             }
5033         }
5034       else if (VECTOR_MODE_P (mode)
5035                ? TREE_CODE (type) != TREE_CODE (TREE_TYPE (typefm))
5036                : TREE_CODE (type) != TREE_CODE (typefm))
5037         {
5038           error ("mode %qs applied to inappropriate type", p);
5039           return NULL_TREE;
5040         }
5041
5042       *node = typefm;
5043     }
5044
5045   return NULL_TREE;
5046 }
5047
5048 /* Handle a "section" attribute; arguments as in
5049    struct attribute_spec.handler.  */
5050
5051 static tree
5052 handle_section_attribute (tree *node, tree ARG_UNUSED (name), tree args,
5053                           int ARG_UNUSED (flags), bool *no_add_attrs)
5054 {
5055   tree decl = *node;
5056
5057   if (targetm.have_named_sections)
5058     {
5059       user_defined_section_attribute = true;
5060
5061       if ((TREE_CODE (decl) == FUNCTION_DECL
5062            || TREE_CODE (decl) == VAR_DECL)
5063           && TREE_CODE (TREE_VALUE (args)) == STRING_CST)
5064         {
5065           if (TREE_CODE (decl) == VAR_DECL
5066               && current_function_decl != NULL_TREE
5067               && !TREE_STATIC (decl))
5068             {
5069               error ("%Jsection attribute cannot be specified for "
5070                      "local variables", decl);
5071               *no_add_attrs = true;
5072             }
5073
5074           /* The decl may have already been given a section attribute
5075              from a previous declaration.  Ensure they match.  */
5076           else if (DECL_SECTION_NAME (decl) != NULL_TREE
5077                    && strcmp (TREE_STRING_POINTER (DECL_SECTION_NAME (decl)),
5078                               TREE_STRING_POINTER (TREE_VALUE (args))) != 0)
5079             {
5080               error ("section of %q+D conflicts with previous declaration",
5081                      *node);
5082               *no_add_attrs = true;
5083             }
5084           else
5085             DECL_SECTION_NAME (decl) = TREE_VALUE (args);
5086         }
5087       else
5088         {
5089           error ("section attribute not allowed for %q+D", *node);
5090           *no_add_attrs = true;
5091         }
5092     }
5093   else
5094     {
5095       error ("%Jsection attributes are not supported for this target", *node);
5096       *no_add_attrs = true;
5097     }
5098
5099   return NULL_TREE;
5100 }
5101
5102 /* Handle a "aligned" attribute; arguments as in
5103    struct attribute_spec.handler.  */
5104
5105 static tree
5106 handle_aligned_attribute (tree *node, tree ARG_UNUSED (name), tree args,
5107                           int flags, bool *no_add_attrs)
5108 {
5109   tree decl = NULL_TREE;
5110   tree *type = NULL;
5111   int is_type = 0;
5112   tree align_expr = (args ? TREE_VALUE (args)
5113                      : size_int (BIGGEST_ALIGNMENT / BITS_PER_UNIT));
5114   int i;
5115
5116   if (DECL_P (*node))
5117     {
5118       decl = *node;
5119       type = &TREE_TYPE (decl);
5120       is_type = TREE_CODE (*node) == TYPE_DECL;
5121     }
5122   else if (TYPE_P (*node))
5123     type = node, is_type = 1;
5124
5125   if (TREE_CODE (align_expr) != INTEGER_CST)
5126     {
5127       error ("requested alignment is not a constant");
5128       *no_add_attrs = true;
5129     }
5130   else if ((i = tree_log2 (align_expr)) == -1)
5131     {
5132       error ("requested alignment is not a power of 2");
5133       *no_add_attrs = true;
5134     }
5135   else if (i > HOST_BITS_PER_INT - 2)
5136     {
5137       error ("requested alignment is too large");
5138       *no_add_attrs = true;
5139     }
5140   else if (is_type)
5141     {
5142       /* If we have a TYPE_DECL, then copy the type, so that we
5143          don't accidentally modify a builtin type.  See pushdecl.  */
5144       if (decl && TREE_TYPE (decl) != error_mark_node
5145           && DECL_ORIGINAL_TYPE (decl) == NULL_TREE)
5146         {
5147           tree tt = TREE_TYPE (decl);
5148           *type = build_variant_type_copy (*type);
5149           DECL_ORIGINAL_TYPE (decl) = tt;
5150           TYPE_NAME (*type) = decl;
5151           TREE_USED (*type) = TREE_USED (decl);
5152           TREE_TYPE (decl) = *type;
5153         }
5154       else if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
5155         *type = build_variant_type_copy (*type);
5156
5157       TYPE_ALIGN (*type) = (1 << i) * BITS_PER_UNIT;
5158       TYPE_USER_ALIGN (*type) = 1;
5159     }
5160   else if (TREE_CODE (decl) != VAR_DECL
5161            && TREE_CODE (decl) != FIELD_DECL)
5162     {
5163       error ("alignment may not be specified for %q+D", decl);
5164       *no_add_attrs = true;
5165     }
5166   else
5167     {
5168       DECL_ALIGN (decl) = (1 << i) * BITS_PER_UNIT;
5169       DECL_USER_ALIGN (decl) = 1;
5170     }
5171
5172   return NULL_TREE;
5173 }
5174
5175 /* Handle a "weak" attribute; arguments as in
5176    struct attribute_spec.handler.  */
5177
5178 static tree
5179 handle_weak_attribute (tree *node, tree name,
5180                        tree ARG_UNUSED (args),
5181                        int ARG_UNUSED (flags),
5182                        bool * ARG_UNUSED (no_add_attrs))
5183 {
5184   if (TREE_CODE (*node) == FUNCTION_DECL
5185       || TREE_CODE (*node) == VAR_DECL)
5186     declare_weak (*node);
5187   else
5188     warning (OPT_Wattributes, "%qE attribute ignored", name);
5189
5190
5191   return NULL_TREE;
5192 }
5193
5194 /* Handle an "alias" attribute; arguments as in
5195    struct attribute_spec.handler.  */
5196
5197 static tree
5198 handle_alias_attribute (tree *node, tree name, tree args,
5199                         int ARG_UNUSED (flags), bool *no_add_attrs)
5200 {
5201   tree decl = *node;
5202
5203   if ((TREE_CODE (decl) == FUNCTION_DECL && DECL_INITIAL (decl))
5204       || (TREE_CODE (decl) != FUNCTION_DECL
5205           && TREE_PUBLIC (decl) && !DECL_EXTERNAL (decl))
5206       /* A static variable declaration is always a tentative definition,
5207          but the alias is a non-tentative definition which overrides.  */
5208       || (TREE_CODE (decl) != FUNCTION_DECL
5209           && ! TREE_PUBLIC (decl) && DECL_INITIAL (decl)))
5210     {
5211       error ("%q+D defined both normally and as an alias", decl);
5212       *no_add_attrs = true;
5213     }
5214
5215   /* Note that the very first time we process a nested declaration,
5216      decl_function_context will not be set.  Indeed, *would* never
5217      be set except for the DECL_INITIAL/DECL_EXTERNAL frobbery that
5218      we do below.  After such frobbery, pushdecl would set the context.
5219      In any case, this is never what we want.  */
5220   else if (decl_function_context (decl) == 0 && current_function_decl == NULL)
5221     {
5222       tree id;
5223
5224       id = TREE_VALUE (args);
5225       if (TREE_CODE (id) != STRING_CST)
5226         {
5227           error ("alias argument not a string");
5228           *no_add_attrs = true;
5229           return NULL_TREE;
5230         }
5231       id = get_identifier (TREE_STRING_POINTER (id));
5232       /* This counts as a use of the object pointed to.  */
5233       TREE_USED (id) = 1;
5234
5235       if (TREE_CODE (decl) == FUNCTION_DECL)
5236         DECL_INITIAL (decl) = error_mark_node;
5237       else
5238         {
5239           if (lookup_attribute ("weakref", DECL_ATTRIBUTES (decl)))
5240             DECL_EXTERNAL (decl) = 1;
5241           else
5242             DECL_EXTERNAL (decl) = 0;
5243           TREE_STATIC (decl) = 1;
5244         }
5245     }
5246   else
5247     {
5248       warning (OPT_Wattributes, "%qE attribute ignored", name);
5249       *no_add_attrs = true;
5250     }
5251
5252   return NULL_TREE;
5253 }
5254
5255 /* Handle a "weakref" attribute; arguments as in struct
5256    attribute_spec.handler.  */
5257
5258 static tree
5259 handle_weakref_attribute (tree *node, tree ARG_UNUSED (name), tree args,
5260                           int flags, bool *no_add_attrs)
5261 {
5262   tree attr = NULL_TREE;
5263
5264   /* We must ignore the attribute when it is associated with
5265      local-scoped decls, since attribute alias is ignored and many
5266      such symbols do not even have a DECL_WEAK field.  */
5267   if (decl_function_context (*node) || current_function_decl)
5268     {
5269       warning (OPT_Wattributes, "%qE attribute ignored", name);
5270       *no_add_attrs = true;
5271       return NULL_TREE;
5272     }
5273
5274   /* The idea here is that `weakref("name")' mutates into `weakref,
5275      alias("name")', and weakref without arguments, in turn,
5276      implicitly adds weak. */
5277
5278   if (args)
5279     {
5280       attr = tree_cons (get_identifier ("alias"), args, attr);
5281       attr = tree_cons (get_identifier ("weakref"), NULL_TREE, attr);
5282
5283       *no_add_attrs = true;
5284
5285       decl_attributes (node, attr, flags);
5286     }
5287   else
5288     {
5289       if (lookup_attribute ("alias", DECL_ATTRIBUTES (*node)))
5290         error ("%Jweakref attribute must appear before alias attribute",
5291                *node);
5292
5293       /* Can't call declare_weak because it wants this to be TREE_PUBLIC,
5294          and that isn't supported; and because it wants to add it to
5295          the list of weak decls, which isn't helpful.  */
5296       DECL_WEAK (*node) = 1;
5297     }
5298
5299   return NULL_TREE;
5300 }
5301
5302 /* Handle an "visibility" attribute; arguments as in
5303    struct attribute_spec.handler.  */
5304
5305 static tree
5306 handle_visibility_attribute (tree *node, tree name, tree args,
5307                              int ARG_UNUSED (flags),
5308                              bool *ARG_UNUSED (no_add_attrs))
5309 {
5310   tree decl = *node;
5311   tree id = TREE_VALUE (args);
5312   enum symbol_visibility vis;
5313
5314   if (TYPE_P (*node))
5315     {
5316       if (TREE_CODE (*node) == ENUMERAL_TYPE)
5317         /* OK */;
5318       else if (TREE_CODE (*node) != RECORD_TYPE && TREE_CODE (*node) != UNION_TYPE)
5319         {
5320           warning (OPT_Wattributes, "%qE attribute ignored on non-class types",
5321                    name);
5322           return NULL_TREE;
5323         }
5324       else if (TYPE_FIELDS (*node))
5325         {
5326           error ("%qE attribute ignored because %qT is already defined",
5327                  name, *node);
5328           return NULL_TREE;
5329         }
5330     }
5331   else if (decl_function_context (decl) != 0 || !TREE_PUBLIC (decl))
5332     {
5333       warning (OPT_Wattributes, "%qE attribute ignored", name);
5334       return NULL_TREE;
5335     }
5336
5337   if (TREE_CODE (id) != STRING_CST)
5338     {
5339       error ("visibility argument not a string");
5340       return NULL_TREE;
5341     }
5342
5343   /*  If this is a type, set the visibility on the type decl.  */
5344   if (TYPE_P (decl))
5345     {
5346       decl = TYPE_NAME (decl);
5347       if (!decl)
5348         return NULL_TREE;
5349       if (TREE_CODE (decl) == IDENTIFIER_NODE)
5350         {
5351            warning (OPT_Wattributes, "%qE attribute ignored on types",
5352                     name);
5353            return NULL_TREE;
5354         }
5355     }
5356
5357   if (strcmp (TREE_STRING_POINTER (id), "default") == 0)
5358     vis = VISIBILITY_DEFAULT;
5359   else if (strcmp (TREE_STRING_POINTER (id), "internal") == 0)
5360     vis = VISIBILITY_INTERNAL;
5361   else if (strcmp (TREE_STRING_POINTER (id), "hidden") == 0)
5362     vis = VISIBILITY_HIDDEN;
5363   else if (strcmp (TREE_STRING_POINTER (id), "protected") == 0)
5364     vis = VISIBILITY_PROTECTED;
5365   else
5366     {
5367       error ("visibility argument must be one of \"default\", \"hidden\", \"protected\" or \"internal\"");
5368       vis = VISIBILITY_DEFAULT;
5369     }
5370
5371   if (DECL_VISIBILITY_SPECIFIED (decl)
5372       && vis != DECL_VISIBILITY (decl)
5373       && lookup_attribute ("visibility", (TYPE_P (*node)
5374                                           ? TYPE_ATTRIBUTES (*node)
5375                                           : DECL_ATTRIBUTES (decl))))
5376     error ("%qD redeclared with different visibility", decl);
5377
5378   DECL_VISIBILITY (decl) = vis;
5379   DECL_VISIBILITY_SPECIFIED (decl) = 1;
5380
5381   /* Go ahead and attach the attribute to the node as well.  This is needed
5382      so we can determine whether we have VISIBILITY_DEFAULT because the
5383      visibility was not specified, or because it was explicitly overridden
5384      from the containing scope.  */
5385
5386   return NULL_TREE;
5387 }
5388
5389 /* Determine the ELF symbol visibility for DECL, which is either a
5390    variable or a function.  It is an error to use this function if a
5391    definition of DECL is not available in this translation unit.
5392    Returns true if the final visibility has been determined by this
5393    function; false if the caller is free to make additional
5394    modifications.  */
5395
5396 bool
5397 c_determine_visibility (tree decl)
5398 {
5399   gcc_assert (TREE_CODE (decl) == VAR_DECL
5400               || TREE_CODE (decl) == FUNCTION_DECL);
5401
5402   /* If the user explicitly specified the visibility with an
5403      attribute, honor that.  DECL_VISIBILITY will have been set during
5404      the processing of the attribute.  We check for an explicit
5405      attribute, rather than just checking DECL_VISIBILITY_SPECIFIED,
5406      to distinguish the use of an attribute from the use of a "#pragma
5407      GCC visibility push(...)"; in the latter case we still want other
5408      considerations to be able to overrule the #pragma.  */
5409   if (lookup_attribute ("visibility", DECL_ATTRIBUTES (decl)))
5410     return true;
5411
5412   /* Anything that is exported must have default visibility.  */
5413   if (TARGET_DLLIMPORT_DECL_ATTRIBUTES
5414       && lookup_attribute ("dllexport", DECL_ATTRIBUTES (decl)))
5415     {
5416       DECL_VISIBILITY (decl) = VISIBILITY_DEFAULT;
5417       DECL_VISIBILITY_SPECIFIED (decl) = 1;
5418       return true;
5419     }
5420
5421   /* Set default visibility to whatever the user supplied with
5422      visibility_specified depending on #pragma GCC visibility.  */
5423   if (!DECL_VISIBILITY_SPECIFIED (decl))
5424     {
5425       DECL_VISIBILITY (decl) = default_visibility;
5426       DECL_VISIBILITY_SPECIFIED (decl) = visibility_options.inpragma;
5427     }
5428   return false;
5429 }
5430
5431 /* Handle an "tls_model" attribute; arguments as in
5432    struct attribute_spec.handler.  */
5433
5434 static tree
5435 handle_tls_model_attribute (tree *node, tree name, tree args,
5436                             int ARG_UNUSED (flags), bool *no_add_attrs)
5437 {
5438   tree id;
5439   tree decl = *node;
5440   enum tls_model kind;
5441
5442   *no_add_attrs = true;
5443
5444   if (!DECL_THREAD_LOCAL_P (decl))
5445     {
5446       warning (OPT_Wattributes, "%qE attribute ignored", name);
5447       return NULL_TREE;
5448     }
5449
5450   kind = DECL_TLS_MODEL (decl);
5451   id = TREE_VALUE (args);
5452   if (TREE_CODE (id) != STRING_CST)
5453     {
5454       error ("tls_model argument not a string");
5455       return NULL_TREE;
5456     }
5457
5458   if (!strcmp (TREE_STRING_POINTER (id), "local-exec"))
5459     kind = TLS_MODEL_LOCAL_EXEC;
5460   else if (!strcmp (TREE_STRING_POINTER (id), "initial-exec"))
5461     kind = TLS_MODEL_INITIAL_EXEC;
5462   else if (!strcmp (TREE_STRING_POINTER (id), "local-dynamic"))
5463     kind = optimize ? TLS_MODEL_LOCAL_DYNAMIC : TLS_MODEL_GLOBAL_DYNAMIC;
5464   else if (!strcmp (TREE_STRING_POINTER (id), "global-dynamic"))
5465     kind = TLS_MODEL_GLOBAL_DYNAMIC;
5466   else
5467     error ("tls_model argument must be one of \"local-exec\", \"initial-exec\", \"local-dynamic\" or \"global-dynamic\"");
5468
5469   DECL_TLS_MODEL (decl) = kind;
5470   return NULL_TREE;
5471 }
5472
5473 /* Handle a "no_instrument_function" attribute; arguments as in
5474    struct attribute_spec.handler.  */
5475
5476 static tree
5477 handle_no_instrument_function_attribute (tree *node, tree name,
5478                                          tree ARG_UNUSED (args),
5479                                          int ARG_UNUSED (flags),
5480                                          bool *no_add_attrs)
5481 {
5482   tree decl = *node;
5483
5484   if (TREE_CODE (decl) != FUNCTION_DECL)
5485     {
5486       error ("%J%qE attribute applies only to functions", decl, name);
5487       *no_add_attrs = true;
5488     }
5489   else if (DECL_INITIAL (decl))
5490     {
5491       error ("%Jcan%'t set %qE attribute after definition", decl, name);
5492       *no_add_attrs = true;
5493     }
5494   else
5495     DECL_NO_INSTRUMENT_FUNCTION_ENTRY_EXIT (decl) = 1;
5496
5497   return NULL_TREE;
5498 }
5499
5500 /* Handle a "malloc" attribute; arguments as in
5501    struct attribute_spec.handler.  */
5502
5503 static tree
5504 handle_malloc_attribute (tree *node, tree name, tree ARG_UNUSED (args),
5505                          int ARG_UNUSED (flags), bool *no_add_attrs)
5506 {
5507   if (TREE_CODE (*node) == FUNCTION_DECL
5508       && POINTER_TYPE_P (TREE_TYPE (TREE_TYPE (*node))))
5509     DECL_IS_MALLOC (*node) = 1;
5510   else
5511     {
5512       warning (OPT_Wattributes, "%qE attribute ignored", name);
5513       *no_add_attrs = true;
5514     }
5515
5516   return NULL_TREE;
5517 }
5518
5519 /* Handle a "returns_twice" attribute; arguments as in
5520    struct attribute_spec.handler.  */
5521
5522 static tree
5523 handle_returns_twice_attribute (tree *node, tree name, tree ARG_UNUSED (args),
5524                          int ARG_UNUSED (flags), bool *no_add_attrs)
5525 {
5526   if (TREE_CODE (*node) == FUNCTION_DECL)
5527     DECL_IS_RETURNS_TWICE (*node) = 1;
5528   else
5529     {
5530       warning (OPT_Wattributes, "%qE attribute ignored", name);
5531       *no_add_attrs = true;
5532     }
5533
5534   return NULL_TREE;
5535 }
5536
5537 /* Handle a "no_limit_stack" attribute; arguments as in
5538    struct attribute_spec.handler.  */
5539
5540 static tree
5541 handle_no_limit_stack_attribute (tree *node, tree name,
5542                                  tree ARG_UNUSED (args),
5543                                  int ARG_UNUSED (flags),
5544                                  bool *no_add_attrs)
5545 {
5546   tree decl = *node;
5547
5548   if (TREE_CODE (decl) != FUNCTION_DECL)
5549     {
5550       error ("%J%qE attribute applies only to functions", decl, name);
5551       *no_add_attrs = true;
5552     }
5553   else if (DECL_INITIAL (decl))
5554     {
5555       error ("%Jcan%'t set %qE attribute after definition", decl, name);
5556       *no_add_attrs = true;
5557     }
5558   else
5559     DECL_NO_LIMIT_STACK (decl) = 1;
5560
5561   return NULL_TREE;
5562 }
5563
5564 /* Handle a "pure" attribute; arguments as in
5565    struct attribute_spec.handler.  */
5566
5567 static tree
5568 handle_pure_attribute (tree *node, tree name, tree ARG_UNUSED (args),
5569                        int ARG_UNUSED (flags), bool *no_add_attrs)
5570 {
5571   if (TREE_CODE (*node) == FUNCTION_DECL)
5572     DECL_IS_PURE (*node) = 1;
5573   /* ??? TODO: Support types.  */
5574   else
5575     {
5576       warning (OPT_Wattributes, "%qE attribute ignored", name);
5577       *no_add_attrs = true;
5578     }
5579
5580   return NULL_TREE;
5581 }
5582
5583 /* Handle a "no vops" attribute; arguments as in
5584    struct attribute_spec.handler.  */
5585
5586 static tree
5587 handle_novops_attribute (tree *node, tree ARG_UNUSED (name),
5588                          tree ARG_UNUSED (args), int ARG_UNUSED (flags),
5589                          bool *ARG_UNUSED (no_add_attrs))
5590 {
5591   gcc_assert (TREE_CODE (*node) == FUNCTION_DECL);
5592   DECL_IS_NOVOPS (*node) = 1;
5593   return NULL_TREE;
5594 }
5595
5596 /* Handle a "deprecated" attribute; arguments as in
5597    struct attribute_spec.handler.  */
5598
5599 static tree
5600 handle_deprecated_attribute (tree *node, tree name,
5601                              tree ARG_UNUSED (args), int flags,
5602                              bool *no_add_attrs)
5603 {
5604   tree type = NULL_TREE;
5605   int warn = 0;
5606   tree what = NULL_TREE;
5607
5608   if (DECL_P (*node))
5609     {
5610       tree decl = *node;
5611       type = TREE_TYPE (decl);
5612
5613       if (TREE_CODE (decl) == TYPE_DECL
5614           || TREE_CODE (decl) == PARM_DECL
5615           || TREE_CODE (decl) == VAR_DECL
5616           || TREE_CODE (decl) == FUNCTION_DECL
5617           || TREE_CODE (decl) == FIELD_DECL)
5618         TREE_DEPRECATED (decl) = 1;
5619       else
5620         warn = 1;
5621     }
5622   else if (TYPE_P (*node))
5623     {
5624       if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
5625         *node = build_variant_type_copy (*node);
5626       TREE_DEPRECATED (*node) = 1;
5627       type = *node;
5628     }
5629   else
5630     warn = 1;
5631
5632   if (warn)
5633     {
5634       *no_add_attrs = true;
5635       if (type && TYPE_NAME (type))
5636         {
5637           if (TREE_CODE (TYPE_NAME (type)) == IDENTIFIER_NODE)
5638             what = TYPE_NAME (*node);
5639           else if (TREE_CODE (TYPE_NAME (type)) == TYPE_DECL
5640                    && DECL_NAME (TYPE_NAME (type)))
5641             what = DECL_NAME (TYPE_NAME (type));
5642         }
5643       if (what)
5644         warning (OPT_Wattributes, "%qE attribute ignored for %qE", name, what);
5645       else
5646         warning (OPT_Wattributes, "%qE attribute ignored", name);
5647     }
5648
5649   return NULL_TREE;
5650 }
5651
5652 /* Handle a "vector_size" attribute; arguments as in
5653    struct attribute_spec.handler.  */
5654
5655 static tree
5656 handle_vector_size_attribute (tree *node, tree name, tree args,
5657                               int ARG_UNUSED (flags),
5658                               bool *no_add_attrs)
5659 {
5660   unsigned HOST_WIDE_INT vecsize, nunits;
5661   enum machine_mode orig_mode;
5662   tree type = *node, new_type, size;
5663
5664   *no_add_attrs = true;
5665
5666   size = TREE_VALUE (args);
5667
5668   if (!host_integerp (size, 1))
5669     {
5670       warning (OPT_Wattributes, "%qE attribute ignored", name);
5671       return NULL_TREE;
5672     }
5673
5674   /* Get the vector size (in bytes).  */
5675   vecsize = tree_low_cst (size, 1);
5676
5677   /* We need to provide for vector pointers, vector arrays, and
5678      functions returning vectors.  For example:
5679
5680        __attribute__((vector_size(16))) short *foo;
5681
5682      In this case, the mode is SI, but the type being modified is
5683      HI, so we need to look further.  */
5684
5685   while (POINTER_TYPE_P (type)
5686          || TREE_CODE (type) == FUNCTION_TYPE
5687          || TREE_CODE (type) == METHOD_TYPE
5688          || TREE_CODE (type) == ARRAY_TYPE)
5689     type = TREE_TYPE (type);
5690
5691   /* Get the mode of the type being modified.  */
5692   orig_mode = TYPE_MODE (type);
5693
5694   if (TREE_CODE (type) == RECORD_TYPE
5695       || TREE_CODE (type) == UNION_TYPE
5696       || TREE_CODE (type) == VECTOR_TYPE
5697       || (!SCALAR_FLOAT_MODE_P (orig_mode)
5698           && GET_MODE_CLASS (orig_mode) != MODE_INT)
5699       || !host_integerp (TYPE_SIZE_UNIT (type), 1))
5700     {
5701       error ("invalid vector type for attribute %qE", name);
5702       return NULL_TREE;
5703     }
5704
5705   if (vecsize % tree_low_cst (TYPE_SIZE_UNIT (type), 1))
5706     {
5707       error ("vector size not an integral multiple of component size");
5708       return NULL;
5709     }
5710
5711   if (vecsize == 0)
5712     {
5713       error ("zero vector size");
5714       return NULL;
5715     }
5716
5717   /* Calculate how many units fit in the vector.  */
5718   nunits = vecsize / tree_low_cst (TYPE_SIZE_UNIT (type), 1);
5719   if (nunits & (nunits - 1))
5720     {
5721       error ("number of components of the vector not a power of two");
5722       return NULL_TREE;
5723     }
5724
5725   new_type = build_vector_type (type, nunits);
5726
5727   /* Build back pointers if needed.  */
5728   *node = reconstruct_complex_type (*node, new_type);
5729
5730   return NULL_TREE;
5731 }
5732
5733 /* Handle the "nonnull" attribute.  */
5734 static tree
5735 handle_nonnull_attribute (tree *node, tree ARG_UNUSED (name),
5736                           tree args, int ARG_UNUSED (flags),
5737                           bool *no_add_attrs)
5738 {
5739   tree type = *node;
5740   unsigned HOST_WIDE_INT attr_arg_num;
5741
5742   /* If no arguments are specified, all pointer arguments should be
5743      non-null.  Verify a full prototype is given so that the arguments
5744      will have the correct types when we actually check them later.  */
5745   if (!args)
5746     {
5747       if (!TYPE_ARG_TYPES (type))
5748         {
5749           error ("nonnull attribute without arguments on a non-prototype");
5750           *no_add_attrs = true;
5751         }
5752       return NULL_TREE;
5753     }
5754
5755   /* Argument list specified.  Verify that each argument number references
5756      a pointer argument.  */
5757   for (attr_arg_num = 1; args; args = TREE_CHAIN (args))
5758     {
5759       tree argument;
5760       unsigned HOST_WIDE_INT arg_num = 0, ck_num;
5761
5762       if (!get_nonnull_operand (TREE_VALUE (args), &arg_num))
5763         {
5764           error ("nonnull argument has invalid operand number (argument %lu)",
5765                  (unsigned long) attr_arg_num);
5766           *no_add_attrs = true;
5767           return NULL_TREE;
5768         }
5769
5770       argument = TYPE_ARG_TYPES (type);
5771       if (argument)
5772         {
5773           for (ck_num = 1; ; ck_num++)
5774             {
5775               if (!argument || ck_num == arg_num)
5776                 break;
5777               argument = TREE_CHAIN (argument);
5778             }
5779
5780           if (!argument
5781               || TREE_CODE (TREE_VALUE (argument)) == VOID_TYPE)
5782             {
5783               error ("nonnull argument with out-of-range operand number (argument %lu, operand %lu)",
5784                      (unsigned long) attr_arg_num, (unsigned long) arg_num);
5785               *no_add_attrs = true;
5786               return NULL_TREE;
5787             }
5788
5789           if (TREE_CODE (TREE_VALUE (argument)) != POINTER_TYPE)
5790             {
5791               error ("nonnull argument references non-pointer operand (argument %lu, operand %lu)",
5792                    (unsigned long) attr_arg_num, (unsigned long) arg_num);
5793               *no_add_attrs = true;
5794               return NULL_TREE;
5795             }
5796         }
5797     }
5798
5799   return NULL_TREE;
5800 }
5801
5802 /* Check the argument list of a function call for null in argument slots
5803    that are marked as requiring a non-null pointer argument.  The NARGS
5804    arguments are passed in the array ARGARRAY.
5805 */
5806
5807 static void
5808 check_function_nonnull (tree attrs, int nargs, tree *argarray)
5809 {
5810   tree a, args;
5811   int i;
5812
5813   for (a = attrs; a; a = TREE_CHAIN (a))
5814     {
5815       if (is_attribute_p ("nonnull", TREE_PURPOSE (a)))
5816         {
5817           args = TREE_VALUE (a);
5818
5819           /* Walk the argument list.  If we encounter an argument number we
5820              should check for non-null, do it.  If the attribute has no args,
5821              then every pointer argument is checked (in which case the check
5822              for pointer type is done in check_nonnull_arg).  */
5823           for (i = 0; i < nargs; i++)
5824             {
5825               if (!args || nonnull_check_p (args, i + 1))
5826                 check_function_arguments_recurse (check_nonnull_arg, NULL,
5827                                                   argarray[i],
5828                                                   i + 1);
5829             }
5830         }
5831     }
5832 }
5833
5834 /* Check that the Nth argument of a function call (counting backwards
5835    from the end) is a (pointer)0.  The NARGS arguments are passed in the
5836    array ARGARRAY.  */
5837
5838 static void
5839 check_function_sentinel (tree attrs, int nargs, tree *argarray, tree typelist)
5840 {
5841   tree attr = lookup_attribute ("sentinel", attrs);
5842
5843   if (attr)
5844     {
5845       int len = 0;
5846       int pos = 0;
5847       tree sentinel;
5848
5849       /* Skip over the named arguments.  */
5850       while (typelist && len < nargs)
5851         {
5852           typelist = TREE_CHAIN (typelist);
5853           len++;
5854         }
5855
5856       if (TREE_VALUE (attr))
5857         {
5858           tree p = TREE_VALUE (TREE_VALUE (attr));
5859           pos = TREE_INT_CST_LOW (p);
5860         }
5861
5862       /* The sentinel must be one of the varargs, i.e.
5863          in position >= the number of fixed arguments.  */
5864       if ((nargs - 1 - pos) < len)
5865         {
5866           warning (OPT_Wformat,
5867                    "not enough variable arguments to fit a sentinel");
5868           return;
5869         }
5870
5871       /* Validate the sentinel.  */
5872       sentinel = argarray[nargs - 1 - pos];
5873       if ((!POINTER_TYPE_P (TREE_TYPE (sentinel))
5874            || !integer_zerop (sentinel))
5875           /* Although __null (in C++) is only an integer we allow it
5876              nevertheless, as we are guaranteed that it's exactly
5877              as wide as a pointer, and we don't want to force
5878              users to cast the NULL they have written there.
5879              We warn with -Wstrict-null-sentinel, though.  */
5880           && (warn_strict_null_sentinel || null_node != sentinel))
5881         warning (OPT_Wformat, "missing sentinel in function call");
5882     }
5883 }
5884
5885 /* Helper for check_function_nonnull; given a list of operands which
5886    must be non-null in ARGS, determine if operand PARAM_NUM should be
5887    checked.  */
5888
5889 static bool
5890 nonnull_check_p (tree args, unsigned HOST_WIDE_INT param_num)
5891 {
5892   unsigned HOST_WIDE_INT arg_num = 0;
5893
5894   for (; args; args = TREE_CHAIN (args))
5895     {
5896       bool found = get_nonnull_operand (TREE_VALUE (args), &arg_num);
5897
5898       gcc_assert (found);
5899
5900       if (arg_num == param_num)
5901         return true;
5902     }
5903   return false;
5904 }
5905
5906 /* Check that the function argument PARAM (which is operand number
5907    PARAM_NUM) is non-null.  This is called by check_function_nonnull
5908    via check_function_arguments_recurse.  */
5909
5910 static void
5911 check_nonnull_arg (void * ARG_UNUSED (ctx), tree param,
5912                    unsigned HOST_WIDE_INT param_num)
5913 {
5914   /* Just skip checking the argument if it's not a pointer.  This can
5915      happen if the "nonnull" attribute was given without an operand
5916      list (which means to check every pointer argument).  */
5917
5918   if (TREE_CODE (TREE_TYPE (param)) != POINTER_TYPE)
5919     return;
5920
5921   if (integer_zerop (param))
5922     warning (OPT_Wnonnull, "null argument where non-null required "
5923              "(argument %lu)", (unsigned long) param_num);
5924 }
5925
5926 /* Helper for nonnull attribute handling; fetch the operand number
5927    from the attribute argument list.  */
5928
5929 static bool
5930 get_nonnull_operand (tree arg_num_expr, unsigned HOST_WIDE_INT *valp)
5931 {
5932   /* Verify the arg number is a constant.  */
5933   if (TREE_CODE (arg_num_expr) != INTEGER_CST
5934       || TREE_INT_CST_HIGH (arg_num_expr) != 0)
5935     return false;
5936
5937   *valp = TREE_INT_CST_LOW (arg_num_expr);
5938   return true;
5939 }
5940
5941 /* Handle a "nothrow" attribute; arguments as in
5942    struct attribute_spec.handler.  */
5943
5944 static tree
5945 handle_nothrow_attribute (tree *node, tree name, tree ARG_UNUSED (args),
5946                           int ARG_UNUSED (flags), bool *no_add_attrs)
5947 {
5948   if (TREE_CODE (*node) == FUNCTION_DECL)
5949     TREE_NOTHROW (*node) = 1;
5950   /* ??? TODO: Support types.  */
5951   else
5952     {
5953       warning (OPT_Wattributes, "%qE attribute ignored", name);
5954       *no_add_attrs = true;
5955     }
5956
5957   return NULL_TREE;
5958 }
5959
5960 /* Handle a "cleanup" attribute; arguments as in
5961    struct attribute_spec.handler.  */
5962
5963 static tree
5964 handle_cleanup_attribute (tree *node, tree name, tree args,
5965                           int ARG_UNUSED (flags), bool *no_add_attrs)
5966 {
5967   tree decl = *node;
5968   tree cleanup_id, cleanup_decl;
5969
5970   /* ??? Could perhaps support cleanups on TREE_STATIC, much like we do
5971      for global destructors in C++.  This requires infrastructure that
5972      we don't have generically at the moment.  It's also not a feature
5973      we'd be missing too much, since we do have attribute constructor.  */
5974   if (TREE_CODE (decl) != VAR_DECL || TREE_STATIC (decl))
5975     {
5976       warning (OPT_Wattributes, "%qE attribute ignored", name);
5977       *no_add_attrs = true;
5978       return NULL_TREE;
5979     }
5980
5981   /* Verify that the argument is a function in scope.  */
5982   /* ??? We could support pointers to functions here as well, if
5983      that was considered desirable.  */
5984   cleanup_id = TREE_VALUE (args);
5985   if (TREE_CODE (cleanup_id) != IDENTIFIER_NODE)
5986     {
5987       error ("cleanup argument not an identifier");
5988       *no_add_attrs = true;
5989       return NULL_TREE;
5990     }
5991   cleanup_decl = lookup_name (cleanup_id);
5992   if (!cleanup_decl || TREE_CODE (cleanup_decl) != FUNCTION_DECL)
5993     {
5994       error ("cleanup argument not a function");
5995       *no_add_attrs = true;
5996       return NULL_TREE;
5997     }
5998
5999   /* That the function has proper type is checked with the
6000      eventual call to build_function_call.  */
6001
6002   return NULL_TREE;
6003 }
6004
6005 /* Handle a "warn_unused_result" attribute.  No special handling.  */
6006
6007 static tree
6008 handle_warn_unused_result_attribute (tree *node, tree name,
6009                                tree ARG_UNUSED (args),
6010                                int ARG_UNUSED (flags), bool *no_add_attrs)
6011 {
6012   /* Ignore the attribute for functions not returning any value.  */
6013   if (VOID_TYPE_P (TREE_TYPE (*node)))
6014     {
6015       warning (OPT_Wattributes, "%qE attribute ignored", name);
6016       *no_add_attrs = true;
6017     }
6018
6019   return NULL_TREE;
6020 }
6021
6022 /* Handle a "sentinel" attribute.  */
6023
6024 static tree
6025 handle_sentinel_attribute (tree *node, tree name, tree args,
6026                            int ARG_UNUSED (flags), bool *no_add_attrs)
6027 {
6028   tree params = TYPE_ARG_TYPES (*node);
6029
6030   if (!params)
6031     {
6032       warning (OPT_Wattributes,
6033                "%qE attribute requires prototypes with named arguments", name);
6034       *no_add_attrs = true;
6035     }
6036   else
6037     {
6038       while (TREE_CHAIN (params))
6039         params = TREE_CHAIN (params);
6040
6041       if (VOID_TYPE_P (TREE_VALUE (params)))
6042         {
6043           warning (OPT_Wattributes,
6044                    "%qE attribute only applies to variadic functions", name);
6045           *no_add_attrs = true;
6046         }
6047     }
6048
6049   if (args)
6050     {
6051       tree position = TREE_VALUE (args);
6052
6053       if (TREE_CODE (position) != INTEGER_CST)
6054         {
6055           warning (0, "requested position is not an integer constant");
6056           *no_add_attrs = true;
6057         }
6058       else
6059         {
6060           if (tree_int_cst_lt (position, integer_zero_node))
6061             {
6062               warning (0, "requested position is less than zero");
6063               *no_add_attrs = true;
6064             }
6065         }
6066     }
6067
6068   return NULL_TREE;
6069 }
6070 \f
6071 /* Check for valid arguments being passed to a function.
6072    ATTRS is a list of attributes.  There are NARGS arguments in the array
6073    ARGARRAY.  TYPELIST is the list of argument types for the function.
6074  */
6075 void
6076 check_function_arguments (tree attrs, int nargs, tree *argarray, tree typelist)
6077 {
6078   /* Check for null being passed in a pointer argument that must be
6079      non-null.  We also need to do this if format checking is enabled.  */
6080
6081   if (warn_nonnull)
6082     check_function_nonnull (attrs, nargs, argarray);
6083
6084   /* Check for errors in format strings.  */
6085
6086   if (warn_format || warn_missing_format_attribute)
6087     check_function_format (attrs, nargs, argarray);
6088
6089   if (warn_format)
6090     check_function_sentinel (attrs, nargs, argarray, typelist);
6091 }
6092
6093 /* Generic argument checking recursion routine.  PARAM is the argument to
6094    be checked.  PARAM_NUM is the number of the argument.  CALLBACK is invoked
6095    once the argument is resolved.  CTX is context for the callback.  */
6096 void
6097 check_function_arguments_recurse (void (*callback)
6098                                   (void *, tree, unsigned HOST_WIDE_INT),
6099                                   void *ctx, tree param,
6100                                   unsigned HOST_WIDE_INT param_num)
6101 {
6102   if ((TREE_CODE (param) == NOP_EXPR || TREE_CODE (param) == CONVERT_EXPR)
6103       && (TYPE_PRECISION (TREE_TYPE (param))
6104           == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (param, 0)))))
6105     {
6106       /* Strip coercion.  */
6107       check_function_arguments_recurse (callback, ctx,
6108                                         TREE_OPERAND (param, 0), param_num);
6109       return;
6110     }
6111
6112   if (TREE_CODE (param) == CALL_EXPR)
6113     {
6114       tree type = TREE_TYPE (TREE_TYPE (CALL_EXPR_FN (param)));
6115       tree attrs;
6116       bool found_format_arg = false;
6117
6118       /* See if this is a call to a known internationalization function
6119          that modifies a format arg.  Such a function may have multiple
6120          format_arg attributes (for example, ngettext).  */
6121
6122       for (attrs = TYPE_ATTRIBUTES (type);
6123            attrs;
6124            attrs = TREE_CHAIN (attrs))
6125         if (is_attribute_p ("format_arg", TREE_PURPOSE (attrs)))
6126           {
6127             tree inner_arg;
6128             tree format_num_expr;
6129             int format_num;
6130             int i;
6131             call_expr_arg_iterator iter;
6132
6133             /* Extract the argument number, which was previously checked
6134                to be valid.  */
6135             format_num_expr = TREE_VALUE (TREE_VALUE (attrs));
6136
6137             gcc_assert (TREE_CODE (format_num_expr) == INTEGER_CST
6138                         && !TREE_INT_CST_HIGH (format_num_expr));
6139
6140             format_num = TREE_INT_CST_LOW (format_num_expr);
6141
6142             for (inner_arg = first_call_expr_arg (param, &iter), i = 1;
6143                  inner_arg != 0;
6144                  inner_arg = next_call_expr_arg (&iter), i++)
6145               if (i == format_num)
6146                 {
6147                   check_function_arguments_recurse (callback, ctx,
6148                                                     inner_arg, param_num);
6149                   found_format_arg = true;
6150                   break;
6151                 }
6152           }
6153
6154       /* If we found a format_arg attribute and did a recursive check,
6155          we are done with checking this argument.  Otherwise, we continue
6156          and this will be considered a non-literal.  */
6157       if (found_format_arg)
6158         return;
6159     }
6160
6161   if (TREE_CODE (param) == COND_EXPR)
6162     {
6163       /* Check both halves of the conditional expression.  */
6164       check_function_arguments_recurse (callback, ctx,
6165                                         TREE_OPERAND (param, 1), param_num);
6166       check_function_arguments_recurse (callback, ctx,
6167                                         TREE_OPERAND (param, 2), param_num);
6168       return;
6169     }
6170
6171   (*callback) (ctx, param, param_num);
6172 }
6173
6174 /* Function to help qsort sort FIELD_DECLs by name order.  */
6175
6176 int
6177 field_decl_cmp (const void *x_p, const void *y_p)
6178 {
6179   const tree *const x = (const tree *const) x_p;
6180   const tree *const y = (const tree *const) y_p;
6181
6182   if (DECL_NAME (*x) == DECL_NAME (*y))
6183     /* A nontype is "greater" than a type.  */
6184     return (TREE_CODE (*y) == TYPE_DECL) - (TREE_CODE (*x) == TYPE_DECL);
6185   if (DECL_NAME (*x) == NULL_TREE)
6186     return -1;
6187   if (DECL_NAME (*y) == NULL_TREE)
6188     return 1;
6189   if (DECL_NAME (*x) < DECL_NAME (*y))
6190     return -1;
6191   return 1;
6192 }
6193
6194 static struct {
6195   gt_pointer_operator new_value;
6196   void *cookie;
6197 } resort_data;
6198
6199 /* This routine compares two fields like field_decl_cmp but using the
6200 pointer operator in resort_data.  */
6201
6202 static int
6203 resort_field_decl_cmp (const void *x_p, const void *y_p)
6204 {
6205   const tree *const x = (const tree *const) x_p;
6206   const tree *const y = (const tree *const) y_p;
6207
6208   if (DECL_NAME (*x) == DECL_NAME (*y))
6209     /* A nontype is "greater" than a type.  */
6210     return (TREE_CODE (*y) == TYPE_DECL) - (TREE_CODE (*x) == TYPE_DECL);
6211   if (DECL_NAME (*x) == NULL_TREE)
6212     return -1;
6213   if (DECL_NAME (*y) == NULL_TREE)
6214     return 1;
6215   {
6216     tree d1 = DECL_NAME (*x);
6217     tree d2 = DECL_NAME (*y);
6218     resort_data.new_value (&d1, resort_data.cookie);
6219     resort_data.new_value (&d2, resort_data.cookie);
6220     if (d1 < d2)
6221       return -1;
6222   }
6223   return 1;
6224 }
6225
6226 /* Resort DECL_SORTED_FIELDS because pointers have been reordered.  */
6227
6228 void
6229 resort_sorted_fields (void *obj,
6230                       void * ARG_UNUSED (orig_obj),
6231                       gt_pointer_operator new_value,
6232                       void *cookie)
6233 {
6234   struct sorted_fields_type *sf = (struct sorted_fields_type *) obj;
6235   resort_data.new_value = new_value;
6236   resort_data.cookie = cookie;
6237   qsort (&sf->elts[0], sf->len, sizeof (tree),
6238          resort_field_decl_cmp);
6239 }
6240
6241 /* Subroutine of c_parse_error.
6242    Return the result of concatenating LHS and RHS. RHS is really
6243    a string literal, its first character is indicated by RHS_START and
6244    RHS_SIZE is its length (including the terminating NUL character).
6245
6246    The caller is responsible for deleting the returned pointer.  */
6247
6248 static char *
6249 catenate_strings (const char *lhs, const char *rhs_start, int rhs_size)
6250 {
6251   const int lhs_size = strlen (lhs);
6252   char *result = XNEWVEC (char, lhs_size + rhs_size);
6253   strncpy (result, lhs, lhs_size);
6254   strncpy (result + lhs_size, rhs_start, rhs_size);
6255   return result;
6256 }
6257
6258 /* Issue the error given by GMSGID, indicating that it occurred before
6259    TOKEN, which had the associated VALUE.  */
6260
6261 void
6262 c_parse_error (const char *gmsgid, enum cpp_ttype token, tree value)
6263 {
6264 #define catenate_messages(M1, M2) catenate_strings ((M1), (M2), sizeof (M2))
6265
6266   char *message = NULL;
6267
6268   if (token == CPP_EOF)
6269     message = catenate_messages (gmsgid, " at end of input");
6270   else if (token == CPP_CHAR || token == CPP_WCHAR)
6271     {
6272       unsigned int val = TREE_INT_CST_LOW (value);
6273       const char *const ell = (token == CPP_CHAR) ? "" : "L";
6274       if (val <= UCHAR_MAX && ISGRAPH (val))
6275         message = catenate_messages (gmsgid, " before %s'%c'");
6276       else
6277         message = catenate_messages (gmsgid, " before %s'\\x%x'");
6278
6279       error (message, ell, val);
6280       free (message);
6281       message = NULL;
6282     }
6283   else if (token == CPP_STRING || token == CPP_WSTRING)
6284     message = catenate_messages (gmsgid, " before string constant");
6285   else if (token == CPP_NUMBER)
6286     message = catenate_messages (gmsgid, " before numeric constant");
6287   else if (token == CPP_NAME)
6288     {
6289       message = catenate_messages (gmsgid, " before %qE");
6290       error (message, value);
6291       free (message);
6292       message = NULL;
6293     }
6294   else if (token == CPP_PRAGMA)
6295     message = catenate_messages (gmsgid, " before %<#pragma%>");
6296   else if (token == CPP_PRAGMA_EOL)
6297     message = catenate_messages (gmsgid, " before end of line");
6298   else if (token < N_TTYPES)
6299     {
6300       message = catenate_messages (gmsgid, " before %qs token");
6301       error (message, cpp_type2name (token));
6302       free (message);
6303       message = NULL;
6304     }
6305   else
6306     error (gmsgid);
6307
6308   if (message)
6309     {
6310       error (message);
6311       free (message);
6312     }
6313 #undef catenate_messages
6314 }
6315
6316 /* Walk a gimplified function and warn for functions whose return value is
6317    ignored and attribute((warn_unused_result)) is set.  This is done before
6318    inlining, so we don't have to worry about that.  */
6319
6320 void
6321 c_warn_unused_result (tree *top_p)
6322 {
6323   tree t = *top_p;
6324   tree_stmt_iterator i;
6325   tree fdecl, ftype;
6326
6327   switch (TREE_CODE (t))
6328     {
6329     case STATEMENT_LIST:
6330       for (i = tsi_start (*top_p); !tsi_end_p (i); tsi_next (&i))
6331         c_warn_unused_result (tsi_stmt_ptr (i));
6332       break;
6333
6334     case COND_EXPR:
6335       c_warn_unused_result (&COND_EXPR_THEN (t));
6336       c_warn_unused_result (&COND_EXPR_ELSE (t));
6337       break;
6338     case BIND_EXPR:
6339       c_warn_unused_result (&BIND_EXPR_BODY (t));
6340       break;
6341     case TRY_FINALLY_EXPR:
6342     case TRY_CATCH_EXPR:
6343       c_warn_unused_result (&TREE_OPERAND (t, 0));
6344       c_warn_unused_result (&TREE_OPERAND (t, 1));
6345       break;
6346     case CATCH_EXPR:
6347       c_warn_unused_result (&CATCH_BODY (t));
6348       break;
6349     case EH_FILTER_EXPR:
6350       c_warn_unused_result (&EH_FILTER_FAILURE (t));
6351       break;
6352
6353     case CALL_EXPR:
6354       if (TREE_USED (t))
6355         break;
6356
6357       /* This is a naked call, as opposed to a CALL_EXPR nested inside
6358          a MODIFY_EXPR.  All calls whose value is ignored should be
6359          represented like this.  Look for the attribute.  */
6360       fdecl = get_callee_fndecl (t);
6361       if (fdecl)
6362         ftype = TREE_TYPE (fdecl);
6363       else
6364         {
6365           ftype = TREE_TYPE (CALL_EXPR_FN (t));
6366           /* Look past pointer-to-function to the function type itself.  */
6367           ftype = TREE_TYPE (ftype);
6368         }
6369
6370       if (lookup_attribute ("warn_unused_result", TYPE_ATTRIBUTES (ftype)))
6371         {
6372           if (fdecl)
6373             warning (0, "%Hignoring return value of %qD, "
6374                      "declared with attribute warn_unused_result",
6375                      EXPR_LOCUS (t), fdecl);
6376           else
6377             warning (0, "%Hignoring return value of function "
6378                      "declared with attribute warn_unused_result",
6379                      EXPR_LOCUS (t));
6380         }
6381       break;
6382
6383     default:
6384       /* Not a container, not a call, or a call whose value is used.  */
6385       break;
6386     }
6387 }
6388
6389 /* Convert a character from the host to the target execution character
6390    set.  cpplib handles this, mostly.  */
6391
6392 HOST_WIDE_INT
6393 c_common_to_target_charset (HOST_WIDE_INT c)
6394 {
6395   /* Character constants in GCC proper are sign-extended under -fsigned-char,
6396      zero-extended under -fno-signed-char.  cpplib insists that characters
6397      and character constants are always unsigned.  Hence we must convert
6398      back and forth.  */
6399   cppchar_t uc = ((cppchar_t)c) & ((((cppchar_t)1) << CHAR_BIT)-1);
6400
6401   uc = cpp_host_to_exec_charset (parse_in, uc);
6402
6403   if (flag_signed_char)
6404     return ((HOST_WIDE_INT)uc) << (HOST_BITS_PER_WIDE_INT - CHAR_TYPE_SIZE)
6405                                >> (HOST_BITS_PER_WIDE_INT - CHAR_TYPE_SIZE);
6406   else
6407     return uc;
6408 }
6409
6410 /* Build the result of __builtin_offsetof.  EXPR is a nested sequence of
6411    component references, with STOP_REF, or alternatively an INDIRECT_REF of
6412    NULL, at the bottom; much like the traditional rendering of offsetof as a
6413    macro.  Returns the folded and properly cast result.  */
6414
6415 static tree
6416 fold_offsetof_1 (tree expr, tree stop_ref)
6417 {
6418   enum tree_code code = PLUS_EXPR;
6419   tree base, off, t;
6420
6421   if (expr == stop_ref && TREE_CODE (expr) != ERROR_MARK)
6422     return size_zero_node;
6423
6424   switch (TREE_CODE (expr))
6425     {
6426     case ERROR_MARK:
6427       return expr;
6428
6429     case VAR_DECL:
6430       error ("cannot apply %<offsetof%> to static data member %qD", expr);
6431       return error_mark_node;
6432
6433     case CALL_EXPR:
6434       error ("cannot apply %<offsetof%> when %<operator[]%> is overloaded");
6435       return error_mark_node;
6436
6437     case INTEGER_CST:
6438       gcc_assert (integer_zerop (expr));
6439       return size_zero_node;
6440
6441     case NOP_EXPR:
6442     case INDIRECT_REF:
6443       base = fold_offsetof_1 (TREE_OPERAND (expr, 0), stop_ref);
6444       gcc_assert (base == error_mark_node || base == size_zero_node);
6445       return base;
6446
6447     case COMPONENT_REF:
6448       base = fold_offsetof_1 (TREE_OPERAND (expr, 0), stop_ref);
6449       if (base == error_mark_node)
6450         return base;
6451
6452       t = TREE_OPERAND (expr, 1);
6453       if (DECL_C_BIT_FIELD (t))
6454         {
6455           error ("attempt to take address of bit-field structure "
6456                  "member %qD", t);
6457           return error_mark_node;
6458         }
6459       off = size_binop (PLUS_EXPR, DECL_FIELD_OFFSET (t),
6460                         size_int (tree_low_cst (DECL_FIELD_BIT_OFFSET (t), 1)
6461                                   / BITS_PER_UNIT));
6462       break;
6463
6464     case ARRAY_REF:
6465       base = fold_offsetof_1 (TREE_OPERAND (expr, 0), stop_ref);
6466       if (base == error_mark_node)
6467         return base;
6468
6469       t = TREE_OPERAND (expr, 1);
6470       if (TREE_CODE (t) == INTEGER_CST && tree_int_cst_sgn (t) < 0)
6471         {
6472           code = MINUS_EXPR;
6473           t = fold_build1 (NEGATE_EXPR, TREE_TYPE (t), t);
6474         }
6475       t = convert (sizetype, t);
6476       off = size_binop (MULT_EXPR, TYPE_SIZE_UNIT (TREE_TYPE (expr)), t);
6477       break;
6478
6479     case COMPOUND_EXPR:
6480       /* Handle static members of volatile structs.  */
6481       t = TREE_OPERAND (expr, 1);
6482       gcc_assert (TREE_CODE (t) == VAR_DECL);
6483       return fold_offsetof_1 (t, stop_ref);
6484
6485     default:
6486       gcc_unreachable ();
6487     }
6488
6489   return size_binop (code, base, off);
6490 }
6491
6492 tree
6493 fold_offsetof (tree expr, tree stop_ref)
6494 {
6495   /* Convert back from the internal sizetype to size_t.  */
6496   return convert (size_type_node, fold_offsetof_1 (expr, stop_ref));
6497 }
6498
6499 /* Print an error message for an invalid lvalue.  USE says
6500    how the lvalue is being used and so selects the error message.  */
6501
6502 void
6503 lvalue_error (enum lvalue_use use)
6504 {
6505   switch (use)
6506     {
6507     case lv_assign:
6508       error ("lvalue required as left operand of assignment");
6509       break;
6510     case lv_increment:
6511       error ("lvalue required as increment operand");
6512       break;
6513     case lv_decrement:
6514       error ("lvalue required as decrement operand");
6515       break;
6516     case lv_addressof:
6517       error ("lvalue required as unary %<&%> operand");
6518       break;
6519     case lv_asm:
6520       error ("lvalue required in asm statement");
6521       break;
6522     default:
6523       gcc_unreachable ();
6524     }
6525 }
6526 \f
6527 /* *PTYPE is an incomplete array.  Complete it with a domain based on
6528    INITIAL_VALUE.  If INITIAL_VALUE is not present, use 1 if DO_DEFAULT
6529    is true.  Return 0 if successful, 1 if INITIAL_VALUE can't be deciphered,
6530    2 if INITIAL_VALUE was NULL, and 3 if INITIAL_VALUE was empty.  */
6531
6532 int
6533 complete_array_type (tree *ptype, tree initial_value, bool do_default)
6534 {
6535   tree maxindex, type, main_type, elt, unqual_elt;
6536   int failure = 0, quals;
6537   hashval_t hashcode = 0;
6538
6539   maxindex = size_zero_node;
6540   if (initial_value)
6541     {
6542       if (TREE_CODE (initial_value) == STRING_CST)
6543         {
6544           int eltsize
6545             = int_size_in_bytes (TREE_TYPE (TREE_TYPE (initial_value)));
6546           maxindex = size_int (TREE_STRING_LENGTH (initial_value)/eltsize - 1);
6547         }
6548       else if (TREE_CODE (initial_value) == CONSTRUCTOR)
6549         {
6550           VEC(constructor_elt,gc) *v = CONSTRUCTOR_ELTS (initial_value);
6551
6552           if (VEC_empty (constructor_elt, v))
6553             {
6554               if (pedantic)
6555                 failure = 3;
6556               maxindex = integer_minus_one_node;
6557             }
6558           else
6559             {
6560               tree curindex;
6561               unsigned HOST_WIDE_INT cnt;
6562               constructor_elt *ce;
6563
6564               if (VEC_index (constructor_elt, v, 0)->index)
6565                 maxindex = fold_convert (sizetype,
6566                                          VEC_index (constructor_elt,
6567                                                     v, 0)->index);
6568               curindex = maxindex;
6569
6570               for (cnt = 1;
6571                    VEC_iterate (constructor_elt, v, cnt, ce);
6572                    cnt++)
6573                 {
6574                   if (ce->index)
6575                     curindex = fold_convert (sizetype, ce->index);
6576                   else
6577                     curindex = size_binop (PLUS_EXPR, curindex, size_one_node);
6578
6579                   if (tree_int_cst_lt (maxindex, curindex))
6580                     maxindex = curindex;
6581                 }
6582             }
6583         }
6584       else
6585         {
6586           /* Make an error message unless that happened already.  */
6587           if (initial_value != error_mark_node)
6588             failure = 1;
6589         }
6590     }
6591   else
6592     {
6593       failure = 2;
6594       if (!do_default)
6595         return failure;
6596     }
6597
6598   type = *ptype;
6599   elt = TREE_TYPE (type);
6600   quals = TYPE_QUALS (strip_array_types (elt));
6601   if (quals == 0)
6602     unqual_elt = elt;
6603   else
6604     unqual_elt = c_build_qualified_type (elt, TYPE_UNQUALIFIED);
6605
6606   /* Using build_distinct_type_copy and modifying things afterward instead
6607      of using build_array_type to create a new type preserves all of the
6608      TYPE_LANG_FLAG_? bits that the front end may have set.  */
6609   main_type = build_distinct_type_copy (TYPE_MAIN_VARIANT (type));
6610   TREE_TYPE (main_type) = unqual_elt;
6611   TYPE_DOMAIN (main_type) = build_index_type (maxindex);
6612   layout_type (main_type);
6613
6614   /* Make sure we have the canonical MAIN_TYPE. */
6615   hashcode = iterative_hash_object (TYPE_HASH (unqual_elt), hashcode);
6616   hashcode = iterative_hash_object (TYPE_HASH (TYPE_DOMAIN (main_type)),
6617                                     hashcode);
6618   main_type = type_hash_canon (hashcode, main_type);
6619
6620   if (quals == 0)
6621     type = main_type;
6622   else
6623     type = c_build_qualified_type (main_type, quals);
6624
6625   *ptype = type;
6626   return failure;
6627 }
6628
6629 \f
6630 /* Used to help initialize the builtin-types.def table.  When a type of
6631    the correct size doesn't exist, use error_mark_node instead of NULL.
6632    The later results in segfaults even when a decl using the type doesn't
6633    get invoked.  */
6634
6635 tree
6636 builtin_type_for_size (int size, bool unsignedp)
6637 {
6638   tree type = lang_hooks.types.type_for_size (size, unsignedp);
6639   return type ? type : error_mark_node;
6640 }
6641
6642 /* A helper function for resolve_overloaded_builtin in resolving the
6643    overloaded __sync_ builtins.  Returns a positive power of 2 if the
6644    first operand of PARAMS is a pointer to a supported data type.
6645    Returns 0 if an error is encountered.  */
6646
6647 static int
6648 sync_resolve_size (tree function, tree params)
6649 {
6650   tree type;
6651   int size;
6652
6653   if (params == NULL)
6654     {
6655       error ("too few arguments to function %qE", function);
6656       return 0;
6657     }
6658
6659   type = TREE_TYPE (TREE_VALUE (params));
6660   if (TREE_CODE (type) != POINTER_TYPE)
6661     goto incompatible;
6662
6663   type = TREE_TYPE (type);
6664   if (!INTEGRAL_TYPE_P (type) && !POINTER_TYPE_P (type))
6665     goto incompatible;
6666
6667   size = tree_low_cst (TYPE_SIZE_UNIT (type), 1);
6668   if (size == 1 || size == 2 || size == 4 || size == 8 || size == 16)
6669     return size;
6670
6671  incompatible:
6672   error ("incompatible type for argument %d of %qE", 1, function);
6673   return 0;
6674 }
6675
6676 /* A helper function for resolve_overloaded_builtin.  Adds casts to
6677    PARAMS to make arguments match up with those of FUNCTION.  Drops
6678    the variadic arguments at the end.  Returns false if some error
6679    was encountered; true on success.  */
6680
6681 static bool
6682 sync_resolve_params (tree orig_function, tree function, tree params)
6683 {
6684   tree arg_types = TYPE_ARG_TYPES (TREE_TYPE (function));
6685   tree ptype;
6686   int number;
6687
6688   /* We've declared the implementation functions to use "volatile void *"
6689      as the pointer parameter, so we shouldn't get any complaints from the
6690      call to check_function_arguments what ever type the user used.  */
6691   arg_types = TREE_CHAIN (arg_types);
6692   ptype = TREE_TYPE (TREE_TYPE (TREE_VALUE (params)));
6693   number = 2;
6694
6695   /* For the rest of the values, we need to cast these to FTYPE, so that we
6696      don't get warnings for passing pointer types, etc.  */
6697   while (arg_types != void_list_node)
6698     {
6699       tree val;
6700
6701       params = TREE_CHAIN (params);
6702       if (params == NULL)
6703         {
6704           error ("too few arguments to function %qE", orig_function);
6705           return false;
6706         }
6707
6708       /* ??? Ideally for the first conversion we'd use convert_for_assignment
6709          so that we get warnings for anything that doesn't match the pointer
6710          type.  This isn't portable across the C and C++ front ends atm.  */
6711       val = TREE_VALUE (params);
6712       val = convert (ptype, val);
6713       val = convert (TREE_VALUE (arg_types), val);
6714       TREE_VALUE (params) = val;
6715
6716       arg_types = TREE_CHAIN (arg_types);
6717       number++;
6718     }
6719
6720   /* The definition of these primitives is variadic, with the remaining
6721      being "an optional list of variables protected by the memory barrier".
6722      No clue what that's supposed to mean, precisely, but we consider all
6723      call-clobbered variables to be protected so we're safe.  */
6724   TREE_CHAIN (params) = NULL;
6725
6726   return true;
6727 }
6728
6729 /* A helper function for resolve_overloaded_builtin.  Adds a cast to
6730    RESULT to make it match the type of the first pointer argument in
6731    PARAMS.  */
6732
6733 static tree
6734 sync_resolve_return (tree params, tree result)
6735 {
6736   tree ptype = TREE_TYPE (TREE_TYPE (TREE_VALUE (params)));
6737   ptype = TYPE_MAIN_VARIANT (ptype);
6738   return convert (ptype, result);
6739 }
6740
6741 /* Some builtin functions are placeholders for other expressions.  This
6742    function should be called immediately after parsing the call expression
6743    before surrounding code has committed to the type of the expression.
6744
6745    FUNCTION is the DECL that has been invoked; it is known to be a builtin.
6746    PARAMS is the argument list for the call.  The return value is non-null
6747    when expansion is complete, and null if normal processing should
6748    continue.  */
6749
6750 tree
6751 resolve_overloaded_builtin (tree function, tree params)
6752 {
6753   enum built_in_function orig_code = DECL_FUNCTION_CODE (function);
6754   switch (DECL_BUILT_IN_CLASS (function))
6755     {
6756     case BUILT_IN_NORMAL:
6757       break;
6758     case BUILT_IN_MD:
6759       if (targetm.resolve_overloaded_builtin)
6760         return targetm.resolve_overloaded_builtin (function, params);
6761       else
6762         return NULL_TREE;
6763     default:
6764       return NULL_TREE;
6765     }
6766
6767   /* Handle BUILT_IN_NORMAL here.  */
6768   switch (orig_code)
6769     {
6770     case BUILT_IN_FETCH_AND_ADD_N:
6771     case BUILT_IN_FETCH_AND_SUB_N:
6772     case BUILT_IN_FETCH_AND_OR_N:
6773     case BUILT_IN_FETCH_AND_AND_N:
6774     case BUILT_IN_FETCH_AND_XOR_N:
6775     case BUILT_IN_FETCH_AND_NAND_N:
6776     case BUILT_IN_ADD_AND_FETCH_N:
6777     case BUILT_IN_SUB_AND_FETCH_N:
6778     case BUILT_IN_OR_AND_FETCH_N:
6779     case BUILT_IN_AND_AND_FETCH_N:
6780     case BUILT_IN_XOR_AND_FETCH_N:
6781     case BUILT_IN_NAND_AND_FETCH_N:
6782     case BUILT_IN_BOOL_COMPARE_AND_SWAP_N:
6783     case BUILT_IN_VAL_COMPARE_AND_SWAP_N:
6784     case BUILT_IN_LOCK_TEST_AND_SET_N:
6785     case BUILT_IN_LOCK_RELEASE_N:
6786       {
6787         int n = sync_resolve_size (function, params);
6788         tree new_function, result;
6789
6790         if (n == 0)
6791           return error_mark_node;
6792
6793         new_function = built_in_decls[orig_code + exact_log2 (n) + 1];
6794         if (!sync_resolve_params (function, new_function, params))
6795           return error_mark_node;
6796
6797         result = build_function_call (new_function, params);
6798         if (orig_code != BUILT_IN_BOOL_COMPARE_AND_SWAP_N
6799             && orig_code != BUILT_IN_LOCK_RELEASE_N)
6800           result = sync_resolve_return (params, result);
6801
6802         return result;
6803       }
6804
6805     default:
6806       return NULL_TREE;
6807     }
6808 }
6809
6810 /* Ignoring their sign, return true if two scalar types are the same.  */
6811 bool
6812 same_scalar_type_ignoring_signedness (tree t1, tree t2)
6813 {
6814   enum tree_code c1 = TREE_CODE (t1), c2 = TREE_CODE (t2);
6815
6816   gcc_assert ((c1 == INTEGER_TYPE || c1 == REAL_TYPE)
6817               && (c2 == INTEGER_TYPE || c2 == REAL_TYPE));
6818
6819   /* Equality works here because c_common_signed_type uses
6820      TYPE_MAIN_VARIANT.  */
6821   return lang_hooks.types.signed_type (t1)
6822     == lang_hooks.types.signed_type (t2);
6823 }
6824
6825 /* Check for missing format attributes on function pointers.  LTYPE is
6826    the new type or left-hand side type.  RTYPE is the old type or
6827    right-hand side type.  Returns TRUE if LTYPE is missing the desired
6828    attribute.  */
6829
6830 bool
6831 check_missing_format_attribute (tree ltype, tree rtype)
6832 {
6833   tree const ttr = TREE_TYPE (rtype), ttl = TREE_TYPE (ltype);
6834   tree ra;
6835
6836   for (ra = TYPE_ATTRIBUTES (ttr); ra; ra = TREE_CHAIN (ra))
6837     if (is_attribute_p ("format", TREE_PURPOSE (ra)))
6838       break;
6839   if (ra)
6840     {
6841       tree la;
6842       for (la = TYPE_ATTRIBUTES (ttl); la; la = TREE_CHAIN (la))
6843         if (is_attribute_p ("format", TREE_PURPOSE (la)))
6844           break;
6845       return !la;
6846     }
6847   else
6848     return false;
6849 }
6850
6851 /* Subscripting with type char is likely to lose on a machine where
6852    chars are signed.  So warn on any machine, but optionally.  Don't
6853    warn for unsigned char since that type is safe.  Don't warn for
6854    signed char because anyone who uses that must have done so
6855    deliberately. Furthermore, we reduce the false positive load by
6856    warning only for non-constant value of type char.  */
6857
6858 void
6859 warn_array_subscript_with_type_char (tree index)
6860 {
6861   if (TYPE_MAIN_VARIANT (TREE_TYPE (index)) == char_type_node
6862       && TREE_CODE (index) != INTEGER_CST)
6863     warning (OPT_Wchar_subscripts, "array subscript has type %<char%>");
6864 }
6865
6866 /* Implement -Wparentheses for the unexpected C precedence rules, to
6867    cover cases like x + y << z which readers are likely to
6868    misinterpret.  We have seen an expression in which CODE is a binary
6869    operator used to combine expressions headed by CODE_LEFT and
6870    CODE_RIGHT.  CODE_LEFT and CODE_RIGHT may be ERROR_MARK, which
6871    means that that side of the expression was not formed using a
6872    binary operator, or it was enclosed in parentheses.  */
6873
6874 void
6875 warn_about_parentheses (enum tree_code code, enum tree_code code_left,
6876                         enum tree_code code_right)
6877 {
6878   if (!warn_parentheses)
6879     return;
6880
6881   if (code == LSHIFT_EXPR || code == RSHIFT_EXPR)
6882     {
6883       if (code_left == PLUS_EXPR || code_left == MINUS_EXPR
6884           || code_right == PLUS_EXPR || code_right == MINUS_EXPR)
6885         warning (OPT_Wparentheses,
6886                  "suggest parentheses around + or - inside shift");
6887     }
6888
6889   if (code == TRUTH_ORIF_EXPR)
6890     {
6891       if (code_left == TRUTH_ANDIF_EXPR
6892           || code_right == TRUTH_ANDIF_EXPR)
6893         warning (OPT_Wparentheses,
6894                  "suggest parentheses around && within ||");
6895     }
6896
6897   if (code == BIT_IOR_EXPR)
6898     {
6899       if (code_left == BIT_AND_EXPR || code_left == BIT_XOR_EXPR
6900           || code_left == PLUS_EXPR || code_left == MINUS_EXPR
6901           || code_right == BIT_AND_EXPR || code_right == BIT_XOR_EXPR
6902           || code_right == PLUS_EXPR || code_right == MINUS_EXPR)
6903         warning (OPT_Wparentheses,
6904                  "suggest parentheses around arithmetic in operand of |");
6905       /* Check cases like x|y==z */
6906       if (TREE_CODE_CLASS (code_left) == tcc_comparison
6907           || TREE_CODE_CLASS (code_right) == tcc_comparison)
6908         warning (OPT_Wparentheses,
6909                  "suggest parentheses around comparison in operand of |");
6910     }
6911
6912   if (code == BIT_XOR_EXPR)
6913     {
6914       if (code_left == BIT_AND_EXPR
6915           || code_left == PLUS_EXPR || code_left == MINUS_EXPR
6916           || code_right == BIT_AND_EXPR
6917           || code_right == PLUS_EXPR || code_right == MINUS_EXPR)
6918         warning (OPT_Wparentheses,
6919                  "suggest parentheses around arithmetic in operand of ^");
6920       /* Check cases like x^y==z */
6921       if (TREE_CODE_CLASS (code_left) == tcc_comparison
6922           || TREE_CODE_CLASS (code_right) == tcc_comparison)
6923         warning (OPT_Wparentheses,
6924                  "suggest parentheses around comparison in operand of ^");
6925     }
6926
6927   if (code == BIT_AND_EXPR)
6928     {
6929       if (code_left == PLUS_EXPR || code_left == MINUS_EXPR
6930           || code_right == PLUS_EXPR || code_right == MINUS_EXPR)
6931         warning (OPT_Wparentheses,
6932                  "suggest parentheses around + or - in operand of &");
6933       /* Check cases like x&y==z */
6934       if (TREE_CODE_CLASS (code_left) == tcc_comparison
6935           || TREE_CODE_CLASS (code_right) == tcc_comparison)
6936         warning (OPT_Wparentheses,
6937                  "suggest parentheses around comparison in operand of &");
6938     }
6939
6940   if (code == EQ_EXPR || code == NE_EXPR)
6941     {
6942       if (TREE_CODE_CLASS (code_left) == tcc_comparison
6943           || TREE_CODE_CLASS (code_right) == tcc_comparison)
6944         warning (OPT_Wparentheses,
6945                  "suggest parentheses around comparison in operand of %s",
6946                  code == EQ_EXPR ? "==" : "!=");
6947     }
6948   else if (TREE_CODE_CLASS (code) == tcc_comparison)
6949     {
6950       if ((TREE_CODE_CLASS (code_left) == tcc_comparison
6951            && code_left != NE_EXPR && code_left != EQ_EXPR)
6952           || (TREE_CODE_CLASS (code_right) == tcc_comparison
6953               && code_right != NE_EXPR && code_right != EQ_EXPR))
6954         warning (OPT_Wparentheses, "comparisons like X<=Y<=Z do not "
6955                  "have their mathematical meaning");
6956     }
6957 }
6958
6959 /* If LABEL (a LABEL_DECL) has not been used, issue a warning.  */
6960
6961 void
6962 warn_for_unused_label (tree label)
6963 {
6964   if (!TREE_USED (label))
6965     {
6966       if (DECL_INITIAL (label))
6967         warning (OPT_Wunused_label, "label %q+D defined but not used", label);
6968       else
6969         warning (OPT_Wunused_label, "label %q+D declared but not defined", label);
6970     }
6971 }
6972
6973 /* If FNDECL is a static constructor or destructor, add it to the list
6974    of functions to be called by the file scope initialization
6975    function.  */
6976
6977 void
6978 c_record_cdtor_fn (tree fndecl)
6979 {
6980   if (targetm.have_ctors_dtors)
6981     return;
6982
6983   if (DECL_STATIC_CONSTRUCTOR (fndecl))
6984     static_ctors = tree_cons (NULL_TREE, fndecl, static_ctors);
6985   if (DECL_STATIC_DESTRUCTOR (fndecl))
6986     static_dtors = tree_cons (NULL_TREE, fndecl, static_dtors);
6987 }
6988
6989 /* Synthesize a function which calls all the global ctors or global
6990    dtors in this file.  This is only used for targets which do not
6991    support .ctors/.dtors sections.  FIXME: Migrate into cgraph.  */
6992 static void
6993 build_cdtor (int method_type, tree cdtors)
6994 {
6995   tree body = 0;
6996
6997   if (!cdtors)
6998     return;
6999
7000   for (; cdtors; cdtors = TREE_CHAIN (cdtors))
7001     append_to_statement_list (build_function_call (TREE_VALUE (cdtors), 0),
7002                               &body);
7003
7004   cgraph_build_static_cdtor (method_type, body, DEFAULT_INIT_PRIORITY);
7005 }
7006
7007 /* Generate functions to call static constructors and destructors
7008    for targets that do not support .ctors/.dtors sections.  These
7009    functions have magic names which are detected by collect2.  */
7010
7011 void
7012 c_build_cdtor_fns (void)
7013 {
7014   if (!targetm.have_ctors_dtors)
7015     {
7016       build_cdtor ('I', static_ctors);
7017       static_ctors = NULL_TREE;
7018       build_cdtor ('D', static_dtors);
7019       static_dtors = NULL_TREE;
7020     }
7021   else
7022     {
7023       gcc_assert (!static_ctors);
7024       gcc_assert (!static_dtors);
7025     }
7026 }
7027
7028 #ifndef TARGET_HAS_TARGETCM
7029 struct gcc_targetcm targetcm = TARGETCM_INITIALIZER;
7030 #endif
7031
7032 /* Warn for division by zero according to the value of DIVISOR.  */
7033
7034 void
7035 warn_for_div_by_zero (tree divisor)
7036 {
7037   /* If DIVISOR is zero, and has integral type, issue a warning about
7038      division by zero.  Do not issue a warning if DIVISOR has a
7039      floating-point type, since we consider 0.0/0.0 a valid way of
7040      generating a NaN.  */
7041   if (skip_evaluation == 0 && integer_zerop (divisor))
7042     warning (OPT_Wdiv_by_zero, "division by zero");
7043 }
7044
7045 #include "gt-c-common.h"