gcc/c-common.c

   1 /* Subroutines shared by all languages that are variants of C.
   2    Copyright (C) 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000,
   3    2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify it under
   8 the terms of the GNU General Public License as published by the Free
   9 Software Foundation; either version 2, or (at your option) any later
  10 version.
  11
  12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15 for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GCC; see the file COPYING.  If not, write to the Free
  19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
  20 02111-1307, 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
  51 cpp_reader *parse_in;           /* Declared in c-pragma.h.  */
  52
  53 /* We let tm.h override the types used here, to handle trivial differences
  54    such as the choice of unsigned int or long unsigned int for size_t.
  55    When machines start needing nontrivial differences in the size type,
  56    it would be best to do something here to figure out automatically
  57    from other information what type to use.  */
  58
  59 #ifndef SIZE_TYPE
  60 #define SIZE_TYPE "long unsigned int"
  61 #endif
  62
  63 #ifndef PID_TYPE
  64 #define PID_TYPE "int"
  65 #endif
  66
  67 #ifndef WCHAR_TYPE
  68 #define WCHAR_TYPE "int"
  69 #endif
  70
  71 /* WCHAR_TYPE gets overridden by -fshort-wchar.  */
  72 #define MODIFIED_WCHAR_TYPE \
  73         (flag_short_wchar ? "short unsigned int" : WCHAR_TYPE)
  74
  75 #ifndef PTRDIFF_TYPE
  76 #define PTRDIFF_TYPE "long int"
  77 #endif
  78
  79 #ifndef WINT_TYPE
  80 #define WINT_TYPE "unsigned int"
  81 #endif
  82
  83 #ifndef INTMAX_TYPE
  84 #define INTMAX_TYPE ((INT_TYPE_SIZE == LONG_LONG_TYPE_SIZE)     \
  85                      ? "int"                                    \
  86                      : ((LONG_TYPE_SIZE == LONG_LONG_TYPE_SIZE) \
  87                         ? "long int"                            \
  88                         : "long long int"))
  89 #endif
  90
  91 #ifndef UINTMAX_TYPE
  92 #define UINTMAX_TYPE ((INT_TYPE_SIZE == LONG_LONG_TYPE_SIZE)    \
  93                      ? "unsigned int"                           \
  94                      : ((LONG_TYPE_SIZE == LONG_LONG_TYPE_SIZE) \
  95                         ? "long unsigned int"                   \
  96                         : "long long unsigned int"))
  97 #endif
  98
  99 /* The following symbols are subsumed in the c_global_trees array, and
 100    listed here individually for documentation purposes.
 101
 102    INTEGER_TYPE and REAL_TYPE nodes for the standard data types.
 103
 104         tree short_integer_type_node;
 105         tree long_integer_type_node;
 106         tree long_long_integer_type_node;
 107
 108         tree short_unsigned_type_node;
 109         tree long_unsigned_type_node;
 110         tree long_long_unsigned_type_node;
 111
 112         tree truthvalue_type_node;
 113         tree truthvalue_false_node;
 114         tree truthvalue_true_node;
 115
 116         tree ptrdiff_type_node;
 117
 118         tree unsigned_char_type_node;
 119         tree signed_char_type_node;
 120         tree wchar_type_node;
 121         tree signed_wchar_type_node;
 122         tree unsigned_wchar_type_node;
 123
 124         tree float_type_node;
 125         tree double_type_node;
 126         tree long_double_type_node;
 127
 128         tree complex_integer_type_node;
 129         tree complex_float_type_node;
 130         tree complex_double_type_node;
 131         tree complex_long_double_type_node;
 132
 133         tree intQI_type_node;
 134         tree intHI_type_node;
 135         tree intSI_type_node;
 136         tree intDI_type_node;
 137         tree intTI_type_node;
 138
 139         tree unsigned_intQI_type_node;
 140         tree unsigned_intHI_type_node;
 141         tree unsigned_intSI_type_node;
 142         tree unsigned_intDI_type_node;
 143         tree unsigned_intTI_type_node;
 144
 145         tree widest_integer_literal_type_node;
 146         tree widest_unsigned_literal_type_node;
 147
 148    Nodes for types `void *' and `const void *'.
 149
 150         tree ptr_type_node, const_ptr_type_node;
 151
 152    Nodes for types `char *' and `const char *'.
 153
 154         tree string_type_node, const_string_type_node;
 155
 156    Type `char[SOMENUMBER]'.
 157    Used when an array of char is needed and the size is irrelevant.
 158
 159         tree char_array_type_node;
 160
 161    Type `int[SOMENUMBER]' or something like it.
 162    Used when an array of int needed and the size is irrelevant.
 163
 164         tree int_array_type_node;
 165
 166    Type `wchar_t[SOMENUMBER]' or something like it.
 167    Used when a wide string literal is created.
 168
 169         tree wchar_array_type_node;
 170
 171    Type `int ()' -- used for implicit declaration of functions.
 172
 173         tree default_function_type;
 174
 175    A VOID_TYPE node, packaged in a TREE_LIST.
 176
 177         tree void_list_node;
 178
 179   The lazily created VAR_DECLs for __FUNCTION__, __PRETTY_FUNCTION__,
 180   and __func__. (C doesn't generate __FUNCTION__ and__PRETTY_FUNCTION__
 181   VAR_DECLS, but C++ does.)
 182
 183         tree function_name_decl_node;
 184         tree pretty_function_name_decl_node;
 185         tree c99_function_name_decl_node;
 186
 187   Stack of nested function name VAR_DECLs.
 188
 189         tree saved_function_name_decls;
 190
 191 */
 192
 193 tree c_global_trees[CTI_MAX];
 194
 195 /* TRUE if a code represents a statement.  The front end init
 196    langhook should take care of initialization of this array.  */
 197
 198 bool statement_code_p[MAX_TREE_CODES];
 199 \f
 200 /* Switches common to the C front ends.  */
 201
 202 /* Nonzero if prepreprocessing only.  */
 203
 204 int flag_preprocess_only;
 205
 206 /* Nonzero means don't output line number information.  */
 207
 208 char flag_no_line_commands;
 209
 210 /* Nonzero causes -E output not to be done, but directives such as
 211    #define that have side effects are still obeyed.  */
 212
 213 char flag_no_output;
 214
 215 /* Nonzero means dump macros in some fashion.  */
 216
 217 char flag_dump_macros;
 218
 219 /* Nonzero means pass #include lines through to the output.  */
 220
 221 char flag_dump_includes;
 222
 223 /* Nonzero means process PCH files while preprocessing.  */
 224
 225 bool flag_pch_preprocess;
 226
 227 /* The file name to which we should write a precompiled header, or
 228    NULL if no header will be written in this compile.  */
 229
 230 const char *pch_file;
 231
 232 /* Nonzero if an ISO standard was selected.  It rejects macros in the
 233    user's namespace.  */
 234 int flag_iso;
 235
 236 /* Nonzero if -undef was given.  It suppresses target built-in macros
 237    and assertions.  */
 238 int flag_undef;
 239
 240 /* Nonzero means don't recognize the non-ANSI builtin functions.  */
 241
 242 int flag_no_builtin;
 243
 244 /* Nonzero means don't recognize the non-ANSI builtin functions.
 245    -ansi sets this.  */
 246
 247 int flag_no_nonansi_builtin;
 248
 249 /* Nonzero means give `double' the same size as `float'.  */
 250
 251 int flag_short_double;
 252
 253 /* Nonzero means give `wchar_t' the same size as `short'.  */
 254
 255 int flag_short_wchar;
 256
 257 /* Nonzero means allow Microsoft extensions without warnings or errors.  */
 258 int flag_ms_extensions;
 259
 260 /* Nonzero means don't recognize the keyword `asm'.  */
 261
 262 int flag_no_asm;
 263
 264 /* Nonzero means give string constants the type `const char *', as mandated
 265    by the standard.  */
 266
 267 int flag_const_strings;
 268
 269 /* Nonzero means to treat bitfields as signed unless they say `unsigned'.  */
 270
 271 int flag_signed_bitfields = 1;
 272
 273 /* Nonzero means warn about deprecated conversion from string constant to
 274    `char *'.  */
 275
 276 int warn_write_strings;
 277
 278 /* Warn about #pragma directives that are not recognized.  */
 279
 280 int warn_unknown_pragmas; /* Tri state variable.  */
 281
 282 /* Warn about format/argument anomalies in calls to formatted I/O functions
 283    (*printf, *scanf, strftime, strfmon, etc.).  */
 284
 285 int warn_format;
 286
 287 /* Zero means that faster, ...NonNil variants of objc_msgSend...
 288    calls will be used in ObjC; passing nil receivers to such calls
 289    will most likely result in crashes.  */
 290 int flag_nil_receivers = 1;
 291
 292 /* Nonzero means that we will allow new ObjC exception syntax (@throw,
 293    @try, etc.) in source code.  */
 294 int flag_objc_exceptions = 0;
 295
 296 /* Nonzero means that we generate NeXT setjmp based exceptions.  */
 297 int flag_objc_sjlj_exceptions = -1;
 298
 299 /* Nonzero means that code generation will be altered to support
 300    "zero-link" execution.  This currently affects ObjC only, but may
 301    affect other languages in the future.  */
 302 int flag_zero_link = 0;
 303
 304 /* Nonzero means emit an '__OBJC, __image_info' for the current translation
 305    unit.  It will inform the ObjC runtime that class definition(s) herein
 306    contained are to replace one(s) previously loaded.  */
 307 int flag_replace_objc_classes = 0;
 308
 309 /* C/ObjC language option variables.  */
 310
 311
 312 /* Nonzero means allow type mismatches in conditional expressions;
 313    just make their values `void'.  */
 314
 315 int flag_cond_mismatch;
 316
 317 /* Nonzero means enable C89 Amendment 1 features.  */
 318
 319 int flag_isoc94;
 320
 321 /* Nonzero means use the ISO C99 dialect of C.  */
 322
 323 int flag_isoc99;
 324
 325 /* Nonzero means that we have builtin functions, and main is an int.  */
 326
 327 int flag_hosted = 1;
 328
 329 /* Warn if main is suspicious.  */
 330
 331 int warn_main;
 332
 333
 334 /* ObjC language option variables.  */
 335
 336
 337 /* Open and close the file for outputting class declarations, if
 338    requested (ObjC).  */
 339
 340 int flag_gen_declaration;
 341
 342 /* Generate code for GNU or NeXT runtime environment.  */
 343
 344 #ifdef NEXT_OBJC_RUNTIME
 345 int flag_next_runtime = 1;
 346 #else
 347 int flag_next_runtime = 0;
 348 #endif
 349
 350 /* Tells the compiler that this is a special run.  Do not perform any
 351    compiling, instead we are to test some platform dependent features
 352    and output a C header file with appropriate definitions.  */
 353
 354 int print_struct_values;
 355
 356 /* ???.  Undocumented.  */
 357
 358 const char *constant_string_class_name;
 359
 360
 361 /* C++ language option variables.  */
 362
 363
 364 /* Nonzero means don't recognize any extension keywords.  */
 365
 366 int flag_no_gnu_keywords;
 367
 368 /* Nonzero means do emit exported implementations of functions even if
 369    they can be inlined.  */
 370
 371 int flag_implement_inlines = 1;
 372
 373 /* Nonzero means that implicit instantiations will be emitted if needed.  */
 374
 375 int flag_implicit_templates = 1;
 376
 377 /* Nonzero means that implicit instantiations of inline templates will be
 378    emitted if needed, even if instantiations of non-inline templates
 379    aren't.  */
 380
 381 int flag_implicit_inline_templates = 1;
 382
 383 /* Nonzero means generate separate instantiation control files and
 384    juggle them at link time.  */
 385
 386 int flag_use_repository;
 387
 388 /* Nonzero if we want to issue diagnostics that the standard says are not
 389    required.  */
 390
 391 int flag_optional_diags = 1;
 392
 393 /* Nonzero means we should attempt to elide constructors when possible.  */
 394
 395 int flag_elide_constructors = 1;
 396
 397 /* Nonzero means that member functions defined in class scope are
 398    inline by default.  */
 399
 400 int flag_default_inline = 1;
 401
 402 /* Controls whether compiler generates 'type descriptor' that give
 403    run-time type information.  */
 404
 405 int flag_rtti = 1;
 406
 407 /* Nonzero if we want to conserve space in the .o files.  We do this
 408    by putting uninitialized data and runtime initialized data into
 409    .common instead of .data at the expense of not flagging multiple
 410    definitions.  */
 411
 412 int flag_conserve_space;
 413
 414 /* Nonzero if we want to obey access control semantics.  */
 415
 416 int flag_access_control = 1;
 417
 418 /* Nonzero if we want to check the return value of new and avoid calling
 419    constructors if it is a null pointer.  */
 420
 421 int flag_check_new;
 422
 423 /* Nonzero if we want the new ISO rules for pushing a new scope for `for'
 424    initialization variables.
 425    0: Old rules, set by -fno-for-scope.
 426    2: New ISO rules, set by -ffor-scope.
 427    1: Try to implement new ISO rules, but with backup compatibility
 428    (and warnings).  This is the default, for now.  */
 429
 430 int flag_new_for_scope = 1;
 431
 432 /* Nonzero if we want to emit defined symbols with common-like linkage as
 433    weak symbols where possible, in order to conform to C++ semantics.
 434    Otherwise, emit them as local symbols.  */
 435
 436 int flag_weak = 1;
 437
 438 /* 0 means we want the preprocessor to not emit line directives for
 439    the current working directory.  1 means we want it to do it.  -1
 440    means we should decide depending on whether debugging information
 441    is being emitted or not.  */
 442
 443 int flag_working_directory = -1;
 444
 445 /* Nonzero to use __cxa_atexit, rather than atexit, to register
 446    destructors for local statics and global objects.  */
 447
 448 int flag_use_cxa_atexit = DEFAULT_USE_CXA_ATEXIT;
 449
 450 /* Nonzero means make the default pedwarns warnings instead of errors.
 451    The value of this flag is ignored if -pedantic is specified.  */
 452
 453 int flag_permissive;
 454
 455 /* Nonzero means to implement standard semantics for exception
 456    specifications, calling unexpected if an exception is thrown that
 457    doesn't match the specification.  Zero means to treat them as
 458    assertions and optimize accordingly, but not check them.  */
 459
 460 int flag_enforce_eh_specs = 1;
 461
 462 /* Nonzero means to generate thread-safe code for initializing local
 463    statics.  */
 464
 465 int flag_threadsafe_statics = 1;
 466
 467 /* Nonzero means warn about implicit declarations.  */
 468
 469 int warn_implicit = 1;
 470
 471 /* Maximum template instantiation depth.  This limit is rather
 472    arbitrary, but it exists to limit the time it takes to notice
 473    infinite template instantiations.  */
 474
 475 int max_tinst_depth = 500;
 476
 477
 478
 479 /* The elements of `ridpointers' are identifier nodes for the reserved
 480    type names and storage classes.  It is indexed by a RID_... value.  */
 481 tree *ridpointers;
 482
 483 tree (*make_fname_decl) (tree, int);
 484
 485 /* Nonzero means the expression being parsed will never be evaluated.
 486    This is a count, since unevaluated expressions can nest.  */
 487 int skip_evaluation;
 488
 489 /* Information about how a function name is generated.  */
 490 struct fname_var_t
 491 {
 492   tree *const decl;     /* pointer to the VAR_DECL.  */
 493   const unsigned rid;   /* RID number for the identifier.  */
 494   const int pretty;     /* How pretty is it? */
 495 };
 496
 497 /* The three ways of getting then name of the current function.  */
 498
 499 const struct fname_var_t fname_vars[] =
 500 {
 501   /* C99 compliant __func__, must be first.  */
 502   {&c99_function_name_decl_node, RID_C99_FUNCTION_NAME, 0},
 503   /* GCC __FUNCTION__ compliant.  */
 504   {&function_name_decl_node, RID_FUNCTION_NAME, 0},
 505   /* GCC __PRETTY_FUNCTION__ compliant.  */
 506   {&pretty_function_name_decl_node, RID_PRETTY_FUNCTION_NAME, 1},
 507   {NULL, 0, 0},
 508 };
 509
 510 static int constant_fits_type_p (tree, tree);
 511 static tree check_case_value (tree);
 512 static bool check_case_bounds (tree, tree, tree *, tree *);
 513
 514 static tree handle_packed_attribute (tree *, tree, tree, int, bool *);
 515 static tree handle_nocommon_attribute (tree *, tree, tree, int, bool *);
 516 static tree handle_common_attribute (tree *, tree, tree, int, bool *);
 517 static tree handle_noreturn_attribute (tree *, tree, tree, int, bool *);
 518 static tree handle_noinline_attribute (tree *, tree, tree, int, bool *);
 519 static tree handle_always_inline_attribute (tree *, tree, tree, int,
 520                                             bool *);
 521 static tree handle_used_attribute (tree *, tree, tree, int, bool *);
 522 static tree handle_unused_attribute (tree *, tree, tree, int, bool *);
 523 static tree handle_const_attribute (tree *, tree, tree, int, bool *);
 524 static tree handle_transparent_union_attribute (tree *, tree, tree,
 525                                                 int, bool *);
 526 static tree handle_constructor_attribute (tree *, tree, tree, int, bool *);
 527 static tree handle_destructor_attribute (tree *, tree, tree, int, bool *);
 528 static tree handle_mode_attribute (tree *, tree, tree, int, bool *);
 529 static tree handle_section_attribute (tree *, tree, tree, int, bool *);
 530 static tree handle_aligned_attribute (tree *, tree, tree, int, bool *);
 531 static tree handle_weak_attribute (tree *, tree, tree, int, bool *) ;
 532 static tree handle_alias_attribute (tree *, tree, tree, int, bool *);
 533 static tree handle_visibility_attribute (tree *, tree, tree, int,
 534                                          bool *);
 535 static tree handle_tls_model_attribute (tree *, tree, tree, int,
 536                                         bool *);
 537 static tree handle_no_instrument_function_attribute (tree *, tree,
 538                                                      tree, int, bool *);
 539 static tree handle_malloc_attribute (tree *, tree, tree, int, bool *);
 540 static tree handle_returns_twice_attribute (tree *, tree, tree, int, bool *);
 541 static tree handle_no_limit_stack_attribute (tree *, tree, tree, int,
 542                                              bool *);
 543 static tree handle_pure_attribute (tree *, tree, tree, int, bool *);
 544 static tree handle_novops_attribute (tree *, tree, tree, int, bool *);
 545 static tree handle_deprecated_attribute (tree *, tree, tree, int,
 546                                          bool *);
 547 static tree handle_vector_size_attribute (tree *, tree, tree, int,
 548                                           bool *);
 549 static tree handle_nonnull_attribute (tree *, tree, tree, int, bool *);
 550 static tree handle_nothrow_attribute (tree *, tree, tree, int, bool *);
 551 static tree handle_cleanup_attribute (tree *, tree, tree, int, bool *);
 552 static tree handle_warn_unused_result_attribute (tree *, tree, tree, int,
 553                                                  bool *);
 554 static tree handle_sentinel_attribute (tree *, tree, tree, int, bool *);
 555
 556 static void check_function_nonnull (tree, tree);
 557 static void check_nonnull_arg (void *, tree, unsigned HOST_WIDE_INT);
 558 static bool nonnull_check_p (tree, unsigned HOST_WIDE_INT);
 559 static bool get_nonnull_operand (tree, unsigned HOST_WIDE_INT *);
 560 static int resort_field_decl_cmp (const void *, const void *);
 561
 562 /* Table of machine-independent attributes common to all C-like languages.  */
 563 const struct attribute_spec c_common_attribute_table[] =
 564 {
 565   /* { name, min_len, max_len, decl_req, type_req, fn_type_req, handler } */
 566   { "packed",                 0, 0, false, false, false,
 567                               handle_packed_attribute },
 568   { "nocommon",               0, 0, true,  false, false,
 569                               handle_nocommon_attribute },
 570   { "common",                 0, 0, true,  false, false,
 571                               handle_common_attribute },
 572   /* FIXME: logically, noreturn attributes should be listed as
 573      "false, true, true" and apply to function types.  But implementing this
 574      would require all the places in the compiler that use TREE_THIS_VOLATILE
 575      on a decl to identify non-returning functions to be located and fixed
 576      to check the function type instead.  */
 577   { "noreturn",               0, 0, true,  false, false,
 578                               handle_noreturn_attribute },
 579   { "volatile",               0, 0, true,  false, false,
 580                               handle_noreturn_attribute },
 581   { "noinline",               0, 0, true,  false, false,
 582                               handle_noinline_attribute },
 583   { "always_inline",          0, 0, true,  false, false,
 584                               handle_always_inline_attribute },
 585   { "used",                   0, 0, true,  false, false,
 586                               handle_used_attribute },
 587   { "unused",                 0, 0, false, false, false,
 588                               handle_unused_attribute },
 589   /* The same comments as for noreturn attributes apply to const ones.  */
 590   { "const",                  0, 0, true,  false, false,
 591                               handle_const_attribute },
 592   { "transparent_union",      0, 0, false, false, false,
 593                               handle_transparent_union_attribute },
 594   { "constructor",            0, 0, true,  false, false,
 595                               handle_constructor_attribute },
 596   { "destructor",             0, 0, true,  false, false,
 597                               handle_destructor_attribute },
 598   { "mode",                   1, 1, false,  true, false,
 599                               handle_mode_attribute },
 600   { "section",                1, 1, true,  false, false,
 601                               handle_section_attribute },
 602   { "aligned",                0, 1, false, false, false,
 603                               handle_aligned_attribute },
 604   { "weak",                   0, 0, true,  false, false,
 605                               handle_weak_attribute },
 606   { "alias",                  1, 1, true,  false, false,
 607                               handle_alias_attribute },
 608   { "no_instrument_function", 0, 0, true,  false, false,
 609                               handle_no_instrument_function_attribute },
 610   { "malloc",                 0, 0, true,  false, false,
 611                               handle_malloc_attribute },
 612   { "returns_twice",          0, 0, true,  false, false,
 613                               handle_returns_twice_attribute },
 614   { "no_stack_limit",         0, 0, true,  false, false,
 615                               handle_no_limit_stack_attribute },
 616   { "pure",                   0, 0, true,  false, false,
 617                               handle_pure_attribute },
 618   /* For internal use (marking of builtins) only.  The name contains space
 619      to prevent its usage in source code.  */
 620   { "no vops",                0, 0, true,  false, false,
 621                               handle_novops_attribute },
 622   { "deprecated",             0, 0, false, false, false,
 623                               handle_deprecated_attribute },
 624   { "vector_size",            1, 1, false, true, false,
 625                               handle_vector_size_attribute },
 626   { "visibility",             1, 1, false, false, false,
 627                               handle_visibility_attribute },
 628   { "tls_model",              1, 1, true,  false, false,
 629                               handle_tls_model_attribute },
 630   { "nonnull",                0, -1, false, true, true,
 631                               handle_nonnull_attribute },
 632   { "nothrow",                0, 0, true,  false, false,
 633                               handle_nothrow_attribute },
 634   { "may_alias",              0, 0, false, true, false, NULL },
 635   { "cleanup",                1, 1, true, false, false,
 636                               handle_cleanup_attribute },
 637   { "warn_unused_result",     0, 0, false, true, true,
 638                               handle_warn_unused_result_attribute },
 639   { "sentinel",               0, 1, false, true, true,
 640                               handle_sentinel_attribute },
 641   { NULL,                     0, 0, false, false, false, NULL }
 642 };
 643
 644 /* Give the specifications for the format attributes, used by C and all
 645    descendants.  */
 646
 647 const struct attribute_spec c_common_format_attribute_table[] =
 648 {
 649   /* { name, min_len, max_len, decl_req, type_req, fn_type_req, handler } */
 650   { "format",                 3, 3, false, true,  true,
 651                               handle_format_attribute },
 652   { "format_arg",             1, 1, false, true,  true,
 653                               handle_format_arg_attribute },
 654   { NULL,                     0, 0, false, false, false, NULL }
 655 };
 656
 657 /* Push current bindings for the function name VAR_DECLS.  */
 658
 659 void
 660 start_fname_decls (void)
 661 {
 662   unsigned ix;
 663   tree saved = NULL_TREE;
 664
 665   for (ix = 0; fname_vars[ix].decl; ix++)
 666     {
 667       tree decl = *fname_vars[ix].decl;
 668
 669       if (decl)
 670         {
 671           saved = tree_cons (decl, build_int_cst (NULL_TREE, ix), saved);
 672           *fname_vars[ix].decl = NULL_TREE;
 673         }
 674     }
 675   if (saved || saved_function_name_decls)
 676     /* Normally they'll have been NULL, so only push if we've got a
 677        stack, or they are non-NULL.  */
 678     saved_function_name_decls = tree_cons (saved, NULL_TREE,
 679                                            saved_function_name_decls);
 680 }
 681
 682 /* Finish up the current bindings, adding them into the current function's
 683    statement tree.  This must be done _before_ finish_stmt_tree is called.
 684    If there is no current function, we must be at file scope and no statements
 685    are involved. Pop the previous bindings.  */
 686
 687 void
 688 finish_fname_decls (void)
 689 {
 690   unsigned ix;
 691   tree stmts = NULL_TREE;
 692   tree stack = saved_function_name_decls;
 693
 694   for (; stack && TREE_VALUE (stack); stack = TREE_CHAIN (stack))
 695     append_to_statement_list (TREE_VALUE (stack), &stmts);
 696
 697   if (stmts)
 698     {
 699       tree *bodyp = &DECL_SAVED_TREE (current_function_decl);
 700
 701       if (TREE_CODE (*bodyp) == BIND_EXPR)
 702         bodyp = &BIND_EXPR_BODY (*bodyp);
 703
 704       append_to_statement_list (*bodyp, &stmts);
 705       *bodyp = stmts;
 706     }
 707
 708   for (ix = 0; fname_vars[ix].decl; ix++)
 709     *fname_vars[ix].decl = NULL_TREE;
 710
 711   if (stack)
 712     {
 713       /* We had saved values, restore them.  */
 714       tree saved;
 715
 716       for (saved = TREE_PURPOSE (stack); saved; saved = TREE_CHAIN (saved))
 717         {
 718           tree decl = TREE_PURPOSE (saved);
 719           unsigned ix = TREE_INT_CST_LOW (TREE_VALUE (saved));
 720
 721           *fname_vars[ix].decl = decl;
 722         }
 723       stack = TREE_CHAIN (stack);
 724     }
 725   saved_function_name_decls = stack;
 726 }
 727
 728 /* Return the text name of the current function, suitably prettified
 729    by PRETTY_P.  Return string must be freed by caller.  */
 730
 731 const char *
 732 fname_as_string (int pretty_p)
 733 {
 734   const char *name = "top level";
 735   char *namep;
 736   int vrb = 2;
 737
 738   if (!pretty_p)
 739     {
 740       name = "";
 741       vrb = 0;
 742     }
 743
 744   if (current_function_decl)
 745     name = lang_hooks.decl_printable_name (current_function_decl, vrb);
 746
 747   if (c_lex_string_translate)
 748     {
 749       int len = strlen (name) + 3; /* Two for '"'s.  One for NULL.  */
 750       cpp_string cstr = { 0, 0 }, strname;
 751
 752       namep = XNEWVEC (char, len);
 753       snprintf (namep, len, "\"%s\"", name);
 754       strname.text = (unsigned char *) namep;
 755       strname.len = len - 1;
 756
 757       if (cpp_interpret_string (parse_in, &strname, 1, &cstr, false))
 758         {
 759           XDELETEVEC (namep);
 760           return (char *) cstr.text;
 761         }
 762     }
 763   else
 764     namep = xstrdup (name);
 765
 766   return namep;
 767 }
 768
 769 /* Expand DECL if it declares an entity not handled by the
 770    common code.  */
 771
 772 int
 773 c_expand_decl (tree decl)
 774 {
 775   if (TREE_CODE (decl) == VAR_DECL && !TREE_STATIC (decl))
 776     {
 777       /* Let the back-end know about this variable.  */
 778       if (!anon_aggr_type_p (TREE_TYPE (decl)))
 779         emit_local_var (decl);
 780       else
 781         expand_anon_union_decl (decl, NULL_TREE,
 782                                 DECL_ANON_UNION_ELEMS (decl));
 783     }
 784   else
 785     return 0;
 786
 787   return 1;
 788 }
 789
 790
 791 /* Return the VAR_DECL for a const char array naming the current
 792    function. If the VAR_DECL has not yet been created, create it
 793    now. RID indicates how it should be formatted and IDENTIFIER_NODE
 794    ID is its name (unfortunately C and C++ hold the RID values of
 795    keywords in different places, so we can't derive RID from ID in
 796    this language independent code.  */
 797
 798 tree
 799 fname_decl (unsigned int rid, tree id)
 800 {
 801   unsigned ix;
 802   tree decl = NULL_TREE;
 803
 804   for (ix = 0; fname_vars[ix].decl; ix++)
 805     if (fname_vars[ix].rid == rid)
 806       break;
 807
 808   decl = *fname_vars[ix].decl;
 809   if (!decl)
 810     {
 811       /* If a tree is built here, it would normally have the lineno of
 812          the current statement.  Later this tree will be moved to the
 813          beginning of the function and this line number will be wrong.
 814          To avoid this problem set the lineno to 0 here; that prevents
 815          it from appearing in the RTL.  */
 816       tree stmts;
 817       location_t saved_location = input_location;
 818 #ifdef USE_MAPPED_LOCATION
 819       input_location = UNKNOWN_LOCATION;
 820 #else
 821       input_line = 0;
 822 #endif
 823
 824       stmts = push_stmt_list ();
 825       decl = (*make_fname_decl) (id, fname_vars[ix].pretty);
 826       stmts = pop_stmt_list (stmts);
 827       if (!IS_EMPTY_STMT (stmts))
 828         saved_function_name_decls
 829           = tree_cons (decl, stmts, saved_function_name_decls);
 830       *fname_vars[ix].decl = decl;
 831       input_location = saved_location;
 832     }
 833   if (!ix && !current_function_decl)
 834     pedwarn ("%qD is not defined outside of function scope", decl);
 835
 836   return decl;
 837 }
 838
 839 /* Given a STRING_CST, give it a suitable array-of-chars data type.  */
 840
 841 tree
 842 fix_string_type (tree value)
 843 {
 844   const int wchar_bytes = TYPE_PRECISION (wchar_type_node) / BITS_PER_UNIT;
 845   const int wide_flag = TREE_TYPE (value) == wchar_array_type_node;
 846   const int nchars_max = flag_isoc99 ? 4095 : 509;
 847   int length = TREE_STRING_LENGTH (value);
 848   int nchars;
 849   tree e_type, i_type, a_type;
 850
 851   /* Compute the number of elements, for the array type.  */
 852   nchars = wide_flag ? length / wchar_bytes : length;
 853
 854   if (pedantic && nchars - 1 > nchars_max && !c_dialect_cxx ())
 855     pedwarn ("string length %qd is greater than the length %qd ISO C%d compilers are required to support",
 856              nchars - 1, nchars_max, flag_isoc99 ? 99 : 89);
 857
 858   e_type = wide_flag ? wchar_type_node : char_type_node;
 859   /* Create the array type for the string constant.  flag_const_strings
 860      says make the string constant an array of const char so that
 861      copying it to a non-const pointer will get a warning.  For C++,
 862      this is the standard behavior.
 863
 864      The C++ front end relies on TYPE_MAIN_VARIANT of a cv-qualified
 865      array type being the unqualified version of that type.
 866      Therefore, if we are constructing an array of const char, we must
 867      construct the matching unqualified array type first.  The C front
 868      end does not require this, but it does no harm, so we do it
 869      unconditionally.  */
 870   i_type = build_index_type (build_int_cst (NULL_TREE, nchars - 1));
 871   a_type = build_array_type (e_type, i_type);
 872   if (flag_const_strings)
 873     a_type = c_build_qualified_type (a_type, TYPE_QUAL_CONST);
 874
 875   TREE_TYPE (value) = a_type;
 876   TREE_CONSTANT (value) = 1;
 877   TREE_INVARIANT (value) = 1;
 878   TREE_READONLY (value) = 1;
 879   TREE_STATIC (value) = 1;
 880   return value;
 881 }
 882 \f
 883 /* Print a warning if a constant expression had overflow in folding.
 884    Invoke this function on every expression that the language
 885    requires to be a constant expression.
 886    Note the ANSI C standard says it is erroneous for a
 887    constant expression to overflow.  */
 888
 889 void
 890 constant_expression_warning (tree value)
 891 {
 892   if ((TREE_CODE (value) == INTEGER_CST || TREE_CODE (value) == REAL_CST
 893        || TREE_CODE (value) == VECTOR_CST
 894        || TREE_CODE (value) == COMPLEX_CST)
 895       && TREE_CONSTANT_OVERFLOW (value) && pedantic)
 896     pedwarn ("overflow in constant expression");
 897 }
 898
 899 /* Print a warning if an expression had overflow in folding.
 900    Invoke this function on every expression that
 901    (1) appears in the source code, and
 902    (2) might be a constant expression that overflowed, and
 903    (3) is not already checked by convert_and_check;
 904    however, do not invoke this function on operands of explicit casts.  */
 905
 906 void
 907 overflow_warning (tree value)
 908 {
 909   if ((TREE_CODE (value) == INTEGER_CST
 910        || (TREE_CODE (value) == COMPLEX_CST
 911            && TREE_CODE (TREE_REALPART (value)) == INTEGER_CST))
 912       && TREE_OVERFLOW (value))
 913     {
 914       TREE_OVERFLOW (value) = 0;
 915       if (skip_evaluation == 0)
 916         warning ("integer overflow in expression");
 917     }
 918   else if ((TREE_CODE (value) == REAL_CST
 919             || (TREE_CODE (value) == COMPLEX_CST
 920                 && TREE_CODE (TREE_REALPART (value)) == REAL_CST))
 921            && TREE_OVERFLOW (value))
 922     {
 923       TREE_OVERFLOW (value) = 0;
 924       if (skip_evaluation == 0)
 925         warning ("floating point overflow in expression");
 926     }
 927   else if (TREE_CODE (value) == VECTOR_CST && TREE_OVERFLOW (value))
 928     {
 929       TREE_OVERFLOW (value) = 0;
 930       if (skip_evaluation == 0)
 931         warning ("vector overflow in expression");
 932     }
 933 }
 934
 935 /* Print a warning if a large constant is truncated to unsigned,
 936    or if -Wconversion is used and a constant < 0 is converted to unsigned.
 937    Invoke this function on every expression that might be implicitly
 938    converted to an unsigned type.  */
 939
 940 void
 941 unsigned_conversion_warning (tree result, tree operand)
 942 {
 943   tree type = TREE_TYPE (result);
 944
 945   if (TREE_CODE (operand) == INTEGER_CST
 946       && TREE_CODE (type) == INTEGER_TYPE
 947       && TYPE_UNSIGNED (type)
 948       && skip_evaluation == 0
 949       && !int_fits_type_p (operand, type))
 950     {
 951       if (!int_fits_type_p (operand, c_common_signed_type (type)))
 952         /* This detects cases like converting -129 or 256 to unsigned char.  */
 953         warning ("large integer implicitly truncated to unsigned type");
 954       else if (warn_conversion)
 955         warning ("negative integer implicitly converted to unsigned type");
 956     }
 957 }
 958
 959 /* Nonzero if constant C has a value that is permissible
 960    for type TYPE (an INTEGER_TYPE).  */
 961
 962 static int
 963 constant_fits_type_p (tree c, tree type)
 964 {
 965   if (TREE_CODE (c) == INTEGER_CST)
 966     return int_fits_type_p (c, type);
 967
 968   c = convert (type, c);
 969   return !TREE_OVERFLOW (c);
 970 }
 971
 972 /* Nonzero if vector types T1 and T2 can be converted to each other
 973    without an explicit cast.  */
 974 int
 975 vector_types_convertible_p (tree t1, tree t2)
 976 {
 977   return targetm.vector_opaque_p (t1)
 978          || targetm.vector_opaque_p (t2)
 979          || (tree_int_cst_equal (TYPE_SIZE (t1), TYPE_SIZE (t2))
 980              && INTEGRAL_TYPE_P (TREE_TYPE (t1))
 981                 == INTEGRAL_TYPE_P (TREE_TYPE (t2)));
 982 }
 983
 984 /* Convert EXPR to TYPE, warning about conversion problems with constants.
 985    Invoke this function on every expression that is converted implicitly,
 986    i.e. because of language rules and not because of an explicit cast.  */
 987
 988 tree
 989 convert_and_check (tree type, tree expr)
 990 {
 991   tree t = convert (type, expr);
 992   if (TREE_CODE (t) == INTEGER_CST)
 993     {
 994       if (TREE_OVERFLOW (t))
 995         {
 996           TREE_OVERFLOW (t) = 0;
 997
 998           /* Do not diagnose overflow in a constant expression merely
 999              because a conversion overflowed.  */
1000           TREE_CONSTANT_OVERFLOW (t) = TREE_CONSTANT_OVERFLOW (expr);
1001
1002           /* No warning for converting 0x80000000 to int.  */
1003           if (!(TYPE_UNSIGNED (type) < TYPE_UNSIGNED (TREE_TYPE (expr))
1004                 && TREE_CODE (TREE_TYPE (expr)) == INTEGER_TYPE
1005                 && TYPE_PRECISION (type) == TYPE_PRECISION (TREE_TYPE (expr))))
1006             /* If EXPR fits in the unsigned version of TYPE,
1007                don't warn unless pedantic.  */
1008             if ((pedantic
1009                  || TYPE_UNSIGNED (type)
1010                  || !constant_fits_type_p (expr,
1011                                            c_common_unsigned_type (type)))
1012                 && skip_evaluation == 0)
1013               warning ("overflow in implicit constant conversion");
1014         }
1015       else
1016         unsigned_conversion_warning (t, expr);
1017     }
1018   return t;
1019 }
1020 \f
1021 /* A node in a list that describes references to variables (EXPR), which are
1022    either read accesses if WRITER is zero, or write accesses, in which case
1023    WRITER is the parent of EXPR.  */
1024 struct tlist
1025 {
1026   struct tlist *next;
1027   tree expr, writer;
1028 };
1029
1030 /* Used to implement a cache the results of a call to verify_tree.  We only
1031    use this for SAVE_EXPRs.  */
1032 struct tlist_cache
1033 {
1034   struct tlist_cache *next;
1035   struct tlist *cache_before_sp;
1036   struct tlist *cache_after_sp;
1037   tree expr;
1038 };
1039
1040 /* Obstack to use when allocating tlist structures, and corresponding
1041    firstobj.  */
1042 static struct obstack tlist_obstack;
1043 static char *tlist_firstobj = 0;
1044
1045 /* Keep track of the identifiers we've warned about, so we can avoid duplicate
1046    warnings.  */
1047 static struct tlist *warned_ids;
1048 /* SAVE_EXPRs need special treatment.  We process them only once and then
1049    cache the results.  */
1050 static struct tlist_cache *save_expr_cache;
1051
1052 static void add_tlist (struct tlist **, struct tlist *, tree, int);
1053 static void merge_tlist (struct tlist **, struct tlist *, int);
1054 static void verify_tree (tree, struct tlist **, struct tlist **, tree);
1055 static int warning_candidate_p (tree);
1056 static void warn_for_collisions (struct tlist *);
1057 static void warn_for_collisions_1 (tree, tree, struct tlist *, int);
1058 static struct tlist *new_tlist (struct tlist *, tree, tree);
1059
1060 /* Create a new struct tlist and fill in its fields.  */
1061 static struct tlist *
1062 new_tlist (struct tlist *next, tree t, tree writer)
1063 {
1064   struct tlist *l;
1065   l = XOBNEW (&tlist_obstack, struct tlist);
1066   l->next = next;
1067   l->expr = t;
1068   l->writer = writer;
1069   return l;
1070 }
1071
1072 /* Add duplicates of the nodes found in ADD to the list *TO.  If EXCLUDE_WRITER
1073    is nonnull, we ignore any node we find which has a writer equal to it.  */
1074
1075 static void
1076 add_tlist (struct tlist **to, struct tlist *add, tree exclude_writer, int copy)
1077 {
1078   while (add)
1079     {
1080       struct tlist *next = add->next;
1081       if (!copy)
1082         add->next = *to;
1083       if (!exclude_writer || add->writer != exclude_writer)
1084         *to = copy ? new_tlist (*to, add->expr, add->writer) : add;
1085       add = next;
1086     }
1087 }
1088
1089 /* Merge the nodes of ADD into TO.  This merging process is done so that for
1090    each variable that already exists in TO, no new node is added; however if
1091    there is a write access recorded in ADD, and an occurrence on TO is only
1092    a read access, then the occurrence in TO will be modified to record the
1093    write.  */
1094
1095 static void
1096 merge_tlist (struct tlist **to, struct tlist *add, int copy)
1097 {
1098   struct tlist **end = to;
1099
1100   while (*end)
1101     end = &(*end)->next;
1102
1103   while (add)
1104     {
1105       int found = 0;
1106       struct tlist *tmp2;
1107       struct tlist *next = add->next;
1108
1109       for (tmp2 = *to; tmp2; tmp2 = tmp2->next)
1110         if (tmp2->expr == add->expr)
1111           {
1112             found = 1;
1113             if (!tmp2->writer)
1114               tmp2->writer = add->writer;
1115           }
1116       if (!found)
1117         {
1118           *end = copy ? add : new_tlist (NULL, add->expr, add->writer);
1119           end = &(*end)->next;
1120           *end = 0;
1121         }
1122       add = next;
1123     }
1124 }
1125
1126 /* WRITTEN is a variable, WRITER is its parent.  Warn if any of the variable
1127    references in list LIST conflict with it, excluding reads if ONLY writers
1128    is nonzero.  */
1129
1130 static void
1131 warn_for_collisions_1 (tree written, tree writer, struct tlist *list,
1132                        int only_writes)
1133 {
1134   struct tlist *tmp;
1135
1136   /* Avoid duplicate warnings.  */
1137   for (tmp = warned_ids; tmp; tmp = tmp->next)
1138     if (tmp->expr == written)
1139       return;
1140
1141   while (list)
1142     {
1143       if (list->expr == written
1144           && list->writer != writer
1145           && (!only_writes || list->writer)
1146           && DECL_NAME (list->expr))
1147         {
1148           warned_ids = new_tlist (warned_ids, written, NULL_TREE);
1149           warning ("operation on %qE may be undefined", list->expr);
1150         }
1151       list = list->next;
1152     }
1153 }
1154
1155 /* Given a list LIST of references to variables, find whether any of these
1156    can cause conflicts due to missing sequence points.  */
1157
1158 static void
1159 warn_for_collisions (struct tlist *list)
1160 {
1161   struct tlist *tmp;
1162
1163   for (tmp = list; tmp; tmp = tmp->next)
1164     {
1165       if (tmp->writer)
1166         warn_for_collisions_1 (tmp->expr, tmp->writer, list, 0);
1167     }
1168 }
1169
1170 /* Return nonzero if X is a tree that can be verified by the sequence point
1171    warnings.  */
1172 static int
1173 warning_candidate_p (tree x)
1174 {
1175   return TREE_CODE (x) == VAR_DECL || TREE_CODE (x) == PARM_DECL;
1176 }
1177
1178 /* Walk the tree X, and record accesses to variables.  If X is written by the
1179    parent tree, WRITER is the parent.
1180    We store accesses in one of the two lists: PBEFORE_SP, and PNO_SP.  If this
1181    expression or its only operand forces a sequence point, then everything up
1182    to the sequence point is stored in PBEFORE_SP.  Everything else gets stored
1183    in PNO_SP.
1184    Once we return, we will have emitted warnings if any subexpression before
1185    such a sequence point could be undefined.  On a higher level, however, the
1186    sequence point may not be relevant, and we'll merge the two lists.
1187
1188    Example: (b++, a) + b;
1189    The call that processes the COMPOUND_EXPR will store the increment of B
1190    in PBEFORE_SP, and the use of A in PNO_SP.  The higher-level call that
1191    processes the PLUS_EXPR will need to merge the two lists so that
1192    eventually, all accesses end up on the same list (and we'll warn about the
1193    unordered subexpressions b++ and b.
1194
1195    A note on merging.  If we modify the former example so that our expression
1196    becomes
1197      (b++, b) + a
1198    care must be taken not simply to add all three expressions into the final
1199    PNO_SP list.  The function merge_tlist takes care of that by merging the
1200    before-SP list of the COMPOUND_EXPR into its after-SP list in a special
1201    way, so that no more than one access to B is recorded.  */
1202
1203 static void
1204 verify_tree (tree x, struct tlist **pbefore_sp, struct tlist **pno_sp,
1205              tree writer)
1206 {
1207   struct tlist *tmp_before, *tmp_nosp, *tmp_list2, *tmp_list3;
1208   enum tree_code code;
1209   enum tree_code_class cl;
1210
1211   /* X may be NULL if it is the operand of an empty statement expression
1212      ({ }).  */
1213   if (x == NULL)
1214     return;
1215
1216  restart:
1217   code = TREE_CODE (x);
1218   cl = TREE_CODE_CLASS (code);
1219
1220   if (warning_candidate_p (x))
1221     {
1222       *pno_sp = new_tlist (*pno_sp, x, writer);
1223       return;
1224     }
1225
1226   switch (code)
1227     {
1228     case CONSTRUCTOR:
1229       return;
1230
1231     case COMPOUND_EXPR:
1232     case TRUTH_ANDIF_EXPR:
1233     case TRUTH_ORIF_EXPR:
1234       tmp_before = tmp_nosp = tmp_list3 = 0;
1235       verify_tree (TREE_OPERAND (x, 0), &tmp_before, &tmp_nosp, NULL_TREE);
1236       warn_for_collisions (tmp_nosp);
1237       merge_tlist (pbefore_sp, tmp_before, 0);
1238       merge_tlist (pbefore_sp, tmp_nosp, 0);
1239       verify_tree (TREE_OPERAND (x, 1), &tmp_list3, pno_sp, NULL_TREE);
1240       merge_tlist (pbefore_sp, tmp_list3, 0);
1241       return;
1242
1243     case COND_EXPR:
1244       tmp_before = tmp_list2 = 0;
1245       verify_tree (TREE_OPERAND (x, 0), &tmp_before, &tmp_list2, NULL_TREE);
1246       warn_for_collisions (tmp_list2);
1247       merge_tlist (pbefore_sp, tmp_before, 0);
1248       merge_tlist (pbefore_sp, tmp_list2, 1);
1249
1250       tmp_list3 = tmp_nosp = 0;
1251       verify_tree (TREE_OPERAND (x, 1), &tmp_list3, &tmp_nosp, NULL_TREE);
1252       warn_for_collisions (tmp_nosp);
1253       merge_tlist (pbefore_sp, tmp_list3, 0);
1254
1255       tmp_list3 = tmp_list2 = 0;
1256       verify_tree (TREE_OPERAND (x, 2), &tmp_list3, &tmp_list2, NULL_TREE);
1257       warn_for_collisions (tmp_list2);
1258       merge_tlist (pbefore_sp, tmp_list3, 0);
1259       /* Rather than add both tmp_nosp and tmp_list2, we have to merge the
1260          two first, to avoid warning for (a ? b++ : b++).  */
1261       merge_tlist (&tmp_nosp, tmp_list2, 0);
1262       add_tlist (pno_sp, tmp_nosp, NULL_TREE, 0);
1263       return;
1264
1265     case PREDECREMENT_EXPR:
1266     case PREINCREMENT_EXPR:
1267     case POSTDECREMENT_EXPR:
1268     case POSTINCREMENT_EXPR:
1269       verify_tree (TREE_OPERAND (x, 0), pno_sp, pno_sp, x);
1270       return;
1271
1272     case MODIFY_EXPR:
1273       tmp_before = tmp_nosp = tmp_list3 = 0;
1274       verify_tree (TREE_OPERAND (x, 1), &tmp_before, &tmp_nosp, NULL_TREE);
1275       verify_tree (TREE_OPERAND (x, 0), &tmp_list3, &tmp_list3, x);
1276       /* Expressions inside the LHS are not ordered wrt. the sequence points
1277          in the RHS.  Example:
1278            *a = (a++, 2)
1279          Despite the fact that the modification of "a" is in the before_sp
1280          list (tmp_before), it conflicts with the use of "a" in the LHS.
1281          We can handle this by adding the contents of tmp_list3
1282          to those of tmp_before, and redoing the collision warnings for that
1283          list.  */
1284       add_tlist (&tmp_before, tmp_list3, x, 1);
1285       warn_for_collisions (tmp_before);
1286       /* Exclude the LHS itself here; we first have to merge it into the
1287          tmp_nosp list.  This is done to avoid warning for "a = a"; if we
1288          didn't exclude the LHS, we'd get it twice, once as a read and once
1289          as a write.  */
1290       add_tlist (pno_sp, tmp_list3, x, 0);
1291       warn_for_collisions_1 (TREE_OPERAND (x, 0), x, tmp_nosp, 1);
1292
1293       merge_tlist (pbefore_sp, tmp_before, 0);
1294       if (warning_candidate_p (TREE_OPERAND (x, 0)))
1295         merge_tlist (&tmp_nosp, new_tlist (NULL, TREE_OPERAND (x, 0), x), 0);
1296       add_tlist (pno_sp, tmp_nosp, NULL_TREE, 1);
1297       return;
1298
1299     case CALL_EXPR:
1300       /* We need to warn about conflicts among arguments and conflicts between
1301          args and the function address.  Side effects of the function address,
1302          however, are not ordered by the sequence point of the call.  */
1303       tmp_before = tmp_nosp = tmp_list2 = tmp_list3 = 0;
1304       verify_tree (TREE_OPERAND (x, 0), &tmp_before, &tmp_nosp, NULL_TREE);
1305       if (TREE_OPERAND (x, 1))
1306         verify_tree (TREE_OPERAND (x, 1), &tmp_list2, &tmp_list3, NULL_TREE);
1307       merge_tlist (&tmp_list3, tmp_list2, 0);
1308       add_tlist (&tmp_before, tmp_list3, NULL_TREE, 0);
1309       add_tlist (&tmp_before, tmp_nosp, NULL_TREE, 0);
1310       warn_for_collisions (tmp_before);
1311       add_tlist (pbefore_sp, tmp_before, NULL_TREE, 0);
1312       return;
1313
1314     case TREE_LIST:
1315       /* Scan all the list, e.g. indices of multi dimensional array.  */
1316       while (x)
1317         {
1318           tmp_before = tmp_nosp = 0;
1319           verify_tree (TREE_VALUE (x), &tmp_before, &tmp_nosp, NULL_TREE);
1320           merge_tlist (&tmp_nosp, tmp_before, 0);
1321           add_tlist (pno_sp, tmp_nosp, NULL_TREE, 0);
1322           x = TREE_CHAIN (x);
1323         }
1324       return;
1325
1326     case SAVE_EXPR:
1327       {
1328         struct tlist_cache *t;
1329         for (t = save_expr_cache; t; t = t->next)
1330           if (t->expr == x)
1331             break;
1332
1333         if (!t)
1334           {
1335             t = XOBNEW (&tlist_obstack, struct tlist_cache);
1336             t->next = save_expr_cache;
1337             t->expr = x;
1338             save_expr_cache = t;
1339
1340             tmp_before = tmp_nosp = 0;
1341             verify_tree (TREE_OPERAND (x, 0), &tmp_before, &tmp_nosp, NULL_TREE);
1342             warn_for_collisions (tmp_nosp);
1343
1344             tmp_list3 = 0;
1345             while (tmp_nosp)
1346               {
1347                 struct tlist *t = tmp_nosp;
1348                 tmp_nosp = t->next;
1349                 merge_tlist (&tmp_list3, t, 0);
1350               }
1351             t->cache_before_sp = tmp_before;
1352             t->cache_after_sp = tmp_list3;
1353           }
1354         merge_tlist (pbefore_sp, t->cache_before_sp, 1);
1355         add_tlist (pno_sp, t->cache_after_sp, NULL_TREE, 1);
1356         return;
1357       }
1358
1359     default:
1360       /* For other expressions, simply recurse on their operands.
1361          Manual tail recursion for unary expressions.
1362          Other non-expressions need not be processed.  */
1363       if (cl == tcc_unary)
1364         {
1365           x = TREE_OPERAND (x, 0);
1366           writer = 0;
1367           goto restart;
1368         }
1369       else if (IS_EXPR_CODE_CLASS (cl))
1370         {
1371           int lp;
1372           int max = TREE_CODE_LENGTH (TREE_CODE (x));
1373           for (lp = 0; lp < max; lp++)
1374             {
1375               tmp_before = tmp_nosp = 0;
1376               verify_tree (TREE_OPERAND (x, lp), &tmp_before, &tmp_nosp, 0);
1377               merge_tlist (&tmp_nosp, tmp_before, 0);
1378               add_tlist (pno_sp, tmp_nosp, NULL_TREE, 0);
1379             }
1380         }
1381       return;
1382     }
1383 }
1384
1385 /* Try to warn for undefined behavior in EXPR due to missing sequence
1386    points.  */
1387
1388 void
1389 verify_sequence_points (tree expr)
1390 {
1391   struct tlist *before_sp = 0, *after_sp = 0;
1392
1393   warned_ids = 0;
1394   save_expr_cache = 0;
1395   if (tlist_firstobj == 0)
1396     {
1397       gcc_obstack_init (&tlist_obstack);
1398       tlist_firstobj = (char *) obstack_alloc (&tlist_obstack, 0);
1399     }
1400
1401   verify_tree (expr, &before_sp, &after_sp, 0);
1402   warn_for_collisions (after_sp);
1403   obstack_free (&tlist_obstack, tlist_firstobj);
1404 }
1405 \f
1406 /* Validate the expression after `case' and apply default promotions.  */
1407
1408 static tree
1409 check_case_value (tree value)
1410 {
1411   if (value == NULL_TREE)
1412     return value;
1413
1414   /* ??? Can we ever get nops here for a valid case value?  We
1415      shouldn't for C.  */
1416   STRIP_TYPE_NOPS (value);
1417   /* In C++, the following is allowed:
1418
1419        const int i = 3;
1420        switch (...) { case i: ... }
1421
1422      So, we try to reduce the VALUE to a constant that way.  */
1423   if (c_dialect_cxx ())
1424     {
1425       value = decl_constant_value (value);
1426       STRIP_TYPE_NOPS (value);
1427       value = fold (value);
1428     }
1429
1430   if (TREE_CODE (value) != INTEGER_CST
1431       && value != error_mark_node)
1432     {
1433       error ("case label does not reduce to an integer constant");
1434       value = error_mark_node;
1435     }
1436   else
1437     /* Promote char or short to int.  */
1438     value = default_conversion (value);
1439
1440   constant_expression_warning (value);
1441
1442   return value;
1443 }
1444 \f
1445 /* See if the case values LOW and HIGH are in the range of the original
1446    type (i.e. before the default conversion to int) of the switch testing
1447    expression.
1448    TYPE is the promoted type of the testing expression, and ORIG_TYPE is
1449    the type before promoting it.  CASE_LOW_P is a pointer to the lower
1450    bound of the case label, and CASE_HIGH_P is the upper bound or NULL
1451    if the case is not a case range.
1452    The caller has to make sure that we are not called with NULL for
1453    CASE_LOW_P (i.e. the default case).
1454    Returns true if the case label is in range of ORIG_TYPE (satured or
1455    untouched) or false if the label is out of range.  */
1456
1457 static bool
1458 check_case_bounds (tree type, tree orig_type,
1459                    tree *case_low_p, tree *case_high_p)
1460 {
1461   tree min_value, max_value;
1462   tree case_low = *case_low_p;
1463   tree case_high = case_high_p ? *case_high_p : case_low;
1464
1465   /* If there was a problem with the original type, do nothing.  */
1466   if (orig_type == error_mark_node)
1467     return true;
1468
1469   min_value = TYPE_MIN_VALUE (orig_type);
1470   max_value = TYPE_MAX_VALUE (orig_type);
1471
1472   /* Case label is less than minimum for type.  */
1473   if (tree_int_cst_compare (case_low, min_value) < 0
1474       && tree_int_cst_compare (case_high, min_value) < 0)
1475     {
1476       warning ("case label value is less than minimum value for type");
1477       return false;
1478     }
1479
1480   /* Case value is greater than maximum for type.  */
1481   if (tree_int_cst_compare (case_low, max_value) > 0
1482       && tree_int_cst_compare (case_high, max_value) > 0)
1483     {
1484       warning ("case label value exceeds maximum value for type");
1485       return false;
1486     }
1487
1488   /* Saturate lower case label value to minimum.  */
1489   if (tree_int_cst_compare (case_high, min_value) >= 0
1490       && tree_int_cst_compare (case_low, min_value) < 0)
1491     {
1492       warning ("lower value in case label range"
1493                " less than minimum value for type");
1494       case_low = min_value;
1495     }
1496
1497   /* Saturate upper case label value to maximum.  */
1498   if (tree_int_cst_compare (case_low, max_value) <= 0
1499       && tree_int_cst_compare (case_high, max_value) > 0)
1500     {
1501       warning ("upper value in case label range"
1502                " exceeds maximum value for type");
1503       case_high = max_value;
1504     }
1505
1506   if (*case_low_p != case_low)
1507     *case_low_p = convert (type, case_low);
1508   if (case_high_p && *case_high_p != case_high)
1509     *case_high_p = convert (type, case_high);
1510
1511   return true;
1512 }
1513 \f
1514 /* Return an integer type with BITS bits of precision,
1515    that is unsigned if UNSIGNEDP is nonzero, otherwise signed.  */
1516
1517 tree
1518 c_common_type_for_size (unsigned int bits, int unsignedp)
1519 {
1520   if (bits == TYPE_PRECISION (integer_type_node))
1521     return unsignedp ? unsigned_type_node : integer_type_node;
1522
1523   if (bits == TYPE_PRECISION (signed_char_type_node))
1524     return unsignedp ? unsigned_char_type_node : signed_char_type_node;
1525
1526   if (bits == TYPE_PRECISION (short_integer_type_node))
1527     return unsignedp ? short_unsigned_type_node : short_integer_type_node;
1528
1529   if (bits == TYPE_PRECISION (long_integer_type_node))
1530     return unsignedp ? long_unsigned_type_node : long_integer_type_node;
1531
1532   if (bits == TYPE_PRECISION (long_long_integer_type_node))
1533     return (unsignedp ? long_long_unsigned_type_node
1534             : long_long_integer_type_node);
1535
1536   if (bits == TYPE_PRECISION (widest_integer_literal_type_node))
1537     return (unsignedp ? widest_unsigned_literal_type_node
1538             : widest_integer_literal_type_node);
1539
1540   if (bits <= TYPE_PRECISION (intQI_type_node))
1541     return unsignedp ? unsigned_intQI_type_node : intQI_type_node;
1542
1543   if (bits <= TYPE_PRECISION (intHI_type_node))
1544     return unsignedp ? unsigned_intHI_type_node : intHI_type_node;
1545
1546   if (bits <= TYPE_PRECISION (intSI_type_node))
1547     return unsignedp ? unsigned_intSI_type_node : intSI_type_node;
1548
1549   if (bits <= TYPE_PRECISION (intDI_type_node))
1550     return unsignedp ? unsigned_intDI_type_node : intDI_type_node;
1551
1552   return 0;
1553 }
1554
1555 /* Used for communication between c_common_type_for_mode and
1556    c_register_builtin_type.  */
1557 static GTY(()) tree registered_builtin_types;
1558
1559 /* Return a data type that has machine mode MODE.
1560    If the mode is an integer,
1561    then UNSIGNEDP selects between signed and unsigned types.  */
1562
1563 tree
1564 c_common_type_for_mode (enum machine_mode mode, int unsignedp)
1565 {
1566   tree t;
1567
1568   if (mode == TYPE_MODE (integer_type_node))
1569     return unsignedp ? unsigned_type_node : integer_type_node;
1570
1571   if (mode == TYPE_MODE (signed_char_type_node))
1572     return unsignedp ? unsigned_char_type_node : signed_char_type_node;
1573
1574   if (mode == TYPE_MODE (short_integer_type_node))
1575     return unsignedp ? short_unsigned_type_node : short_integer_type_node;
1576
1577   if (mode == TYPE_MODE (long_integer_type_node))
1578     return unsignedp ? long_unsigned_type_node : long_integer_type_node;
1579
1580   if (mode == TYPE_MODE (long_long_integer_type_node))
1581     return unsignedp ? long_long_unsigned_type_node : long_long_integer_type_node;
1582
1583   if (mode == TYPE_MODE (widest_integer_literal_type_node))
1584     return unsignedp ? widest_unsigned_literal_type_node
1585                      : widest_integer_literal_type_node;
1586
1587   if (mode == QImode)
1588     return unsignedp ? unsigned_intQI_type_node : intQI_type_node;
1589
1590   if (mode == HImode)
1591     return unsignedp ? unsigned_intHI_type_node : intHI_type_node;
1592
1593   if (mode == SImode)
1594     return unsignedp ? unsigned_intSI_type_node : intSI_type_node;
1595
1596   if (mode == DImode)
1597     return unsignedp ? unsigned_intDI_type_node : intDI_type_node;
1598
1599 #if HOST_BITS_PER_WIDE_INT >= 64
1600   if (mode == TYPE_MODE (intTI_type_node))
1601     return unsignedp ? unsigned_intTI_type_node : intTI_type_node;
1602 #endif
1603
1604   if (mode == TYPE_MODE (float_type_node))
1605     return float_type_node;
1606
1607   if (mode == TYPE_MODE (double_type_node))
1608     return double_type_node;
1609
1610   if (mode == TYPE_MODE (long_double_type_node))
1611     return long_double_type_node;
1612
1613   if (mode == TYPE_MODE (void_type_node))
1614     return void_type_node;
1615
1616   if (mode == TYPE_MODE (build_pointer_type (char_type_node)))
1617     return (unsignedp
1618             ? make_unsigned_type (GET_MODE_PRECISION (mode))
1619             : make_signed_type (GET_MODE_PRECISION (mode)));
1620
1621   if (mode == TYPE_MODE (build_pointer_type (integer_type_node)))
1622     return (unsignedp
1623             ? make_unsigned_type (GET_MODE_PRECISION (mode))
1624             : make_signed_type (GET_MODE_PRECISION (mode)));
1625
1626   if (COMPLEX_MODE_P (mode))
1627     {
1628       enum machine_mode inner_mode;
1629       tree inner_type;
1630
1631       if (mode == TYPE_MODE (complex_float_type_node))
1632         return complex_float_type_node;
1633       if (mode == TYPE_MODE (complex_double_type_node))
1634         return complex_double_type_node;
1635       if (mode == TYPE_MODE (complex_long_double_type_node))
1636         return complex_long_double_type_node;
1637
1638       if (mode == TYPE_MODE (complex_integer_type_node) && !unsignedp)
1639         return complex_integer_type_node;
1640
1641       inner_mode = GET_MODE_INNER (mode);
1642       inner_type = c_common_type_for_mode (inner_mode, unsignedp);
1643       if (inner_type != NULL_TREE)
1644         return build_complex_type (inner_type);
1645     }
1646   else if (VECTOR_MODE_P (mode))
1647     {
1648       enum machine_mode inner_mode = GET_MODE_INNER (mode);
1649       tree inner_type = c_common_type_for_mode (inner_mode, unsignedp);
1650       if (inner_type != NULL_TREE)
1651         return build_vector_type_for_mode (inner_type, mode);
1652     }
1653
1654   for (t = registered_builtin_types; t; t = TREE_CHAIN (t))
1655     if (TYPE_MODE (TREE_VALUE (t)) == mode)
1656       return TREE_VALUE (t);
1657
1658   return 0;
1659 }
1660
1661 /* Return an unsigned type the same as TYPE in other respects.  */
1662 tree
1663 c_common_unsigned_type (tree type)
1664 {
1665   tree type1 = TYPE_MAIN_VARIANT (type);
1666   if (type1 == signed_char_type_node || type1 == char_type_node)
1667     return unsigned_char_type_node;
1668   if (type1 == integer_type_node)
1669     return unsigned_type_node;
1670   if (type1 == short_integer_type_node)
1671     return short_unsigned_type_node;
1672   if (type1 == long_integer_type_node)
1673     return long_unsigned_type_node;
1674   if (type1 == long_long_integer_type_node)
1675     return long_long_unsigned_type_node;
1676   if (type1 == widest_integer_literal_type_node)
1677     return widest_unsigned_literal_type_node;
1678 #if HOST_BITS_PER_WIDE_INT >= 64
1679   if (type1 == intTI_type_node)
1680     return unsigned_intTI_type_node;
1681 #endif
1682   if (type1 == intDI_type_node)
1683     return unsigned_intDI_type_node;
1684   if (type1 == intSI_type_node)
1685     return unsigned_intSI_type_node;
1686   if (type1 == intHI_type_node)
1687     return unsigned_intHI_type_node;
1688   if (type1 == intQI_type_node)
1689     return unsigned_intQI_type_node;
1690
1691   return c_common_signed_or_unsigned_type (1, type);
1692 }
1693
1694 /* Return a signed type the same as TYPE in other respects.  */
1695
1696 tree
1697 c_common_signed_type (tree type)
1698 {
1699   tree type1 = TYPE_MAIN_VARIANT (type);
1700   if (type1 == unsigned_char_type_node || type1 == char_type_node)
1701     return signed_char_type_node;
1702   if (type1 == unsigned_type_node)
1703     return integer_type_node;
1704   if (type1 == short_unsigned_type_node)
1705     return short_integer_type_node;
1706   if (type1 == long_unsigned_type_node)
1707     return long_integer_type_node;
1708   if (type1 == long_long_unsigned_type_node)
1709     return long_long_integer_type_node;
1710   if (type1 == widest_unsigned_literal_type_node)
1711     return widest_integer_literal_type_node;
1712 #if HOST_BITS_PER_WIDE_INT >= 64
1713   if (type1 == unsigned_intTI_type_node)
1714     return intTI_type_node;
1715 #endif
1716   if (type1 == unsigned_intDI_type_node)
1717     return intDI_type_node;
1718   if (type1 == unsigned_intSI_type_node)
1719     return intSI_type_node;
1720   if (type1 == unsigned_intHI_type_node)
1721     return intHI_type_node;
1722   if (type1 == unsigned_intQI_type_node)
1723     return intQI_type_node;
1724
1725   return c_common_signed_or_unsigned_type (0, type);
1726 }
1727
1728 /* Return a type the same as TYPE except unsigned or
1729    signed according to UNSIGNEDP.  */
1730
1731 tree
1732 c_common_signed_or_unsigned_type (int unsignedp, tree type)
1733 {
1734   if (!INTEGRAL_TYPE_P (type)
1735       || TYPE_UNSIGNED (type) == unsignedp)
1736     return type;
1737
1738   /* For ENUMERAL_TYPEs in C++, must check the mode of the types, not
1739      the precision; they have precision set to match their range, but
1740      may use a wider mode to match an ABI.  If we change modes, we may
1741      wind up with bad conversions.  For INTEGER_TYPEs in C, must check
1742      the precision as well, so as to yield correct results for
1743      bit-field types.  C++ does not have these separate bit-field
1744      types, and producing a signed or unsigned variant of an
1745      ENUMERAL_TYPE may cause other problems as well.  */
1746
1747 #define TYPE_OK(node)                                                       \
1748   (TYPE_MODE (type) == TYPE_MODE (node)                                     \
1749    && (c_dialect_cxx () || TYPE_PRECISION (type) == TYPE_PRECISION (node)))
1750   if (TYPE_OK (signed_char_type_node))
1751     return unsignedp ? unsigned_char_type_node : signed_char_type_node;
1752   if (TYPE_OK (integer_type_node))
1753     return unsignedp ? unsigned_type_node : integer_type_node;
1754   if (TYPE_OK (short_integer_type_node))
1755     return unsignedp ? short_unsigned_type_node : short_integer_type_node;
1756   if (TYPE_OK (long_integer_type_node))
1757     return unsignedp ? long_unsigned_type_node : long_integer_type_node;
1758   if (TYPE_OK (long_long_integer_type_node))
1759     return (unsignedp ? long_long_unsigned_type_node
1760             : long_long_integer_type_node);
1761   if (TYPE_OK (widest_integer_literal_type_node))
1762     return (unsignedp ? widest_unsigned_literal_type_node
1763             : widest_integer_literal_type_node);
1764
1765 #if HOST_BITS_PER_WIDE_INT >= 64
1766   if (TYPE_OK (intTI_type_node))
1767     return unsignedp ? unsigned_intTI_type_node : intTI_type_node;
1768 #endif
1769   if (TYPE_OK (intDI_type_node))
1770     return unsignedp ? unsigned_intDI_type_node : intDI_type_node;
1771   if (TYPE_OK (intSI_type_node))
1772     return unsignedp ? unsigned_intSI_type_node : intSI_type_node;
1773   if (TYPE_OK (intHI_type_node))
1774     return unsignedp ? unsigned_intHI_type_node : intHI_type_node;
1775   if (TYPE_OK (intQI_type_node))
1776     return unsignedp ? unsigned_intQI_type_node : intQI_type_node;
1777 #undef TYPE_OK
1778
1779   if (c_dialect_cxx ())
1780     return type;
1781   else
1782     return build_nonstandard_integer_type (TYPE_PRECISION (type), unsignedp);
1783 }
1784
1785 /* The C version of the register_builtin_type langhook.  */
1786
1787 void
1788 c_register_builtin_type (tree type, const char* name)
1789 {
1790   tree decl;
1791
1792   decl = build_decl (TYPE_DECL, get_identifier (name), type);
1793   DECL_ARTIFICIAL (decl) = 1;
1794   if (!TYPE_NAME (type))
1795     TYPE_NAME (type) = decl;
1796   pushdecl (decl);
1797
1798   registered_builtin_types = tree_cons (0, type, registered_builtin_types);
1799 }
1800
1801 \f
1802 /* Return the minimum number of bits needed to represent VALUE in a
1803    signed or unsigned type, UNSIGNEDP says which.  */
1804
1805 unsigned int
1806 min_precision (tree value, int unsignedp)
1807 {
1808   int log;
1809
1810   /* If the value is negative, compute its negative minus 1.  The latter
1811      adjustment is because the absolute value of the largest negative value
1812      is one larger than the largest positive value.  This is equivalent to
1813      a bit-wise negation, so use that operation instead.  */
1814
1815   if (tree_int_cst_sgn (value) < 0)
1816     value = fold (build1 (BIT_NOT_EXPR, TREE_TYPE (value), value));
1817
1818   /* Return the number of bits needed, taking into account the fact
1819      that we need one more bit for a signed than unsigned type.  */
1820
1821   if (integer_zerop (value))
1822     log = 0;
1823   else
1824     log = tree_floor_log2 (value);
1825
1826   return log + 1 + !unsignedp;
1827 }
1828 \f
1829 /* Print an error message for invalid operands to arith operation
1830    CODE.  NOP_EXPR is used as a special case (see
1831    c_common_truthvalue_conversion).  */
1832
1833 void
1834 binary_op_error (enum tree_code code)
1835 {
1836   const char *opname;
1837
1838   switch (code)
1839     {
1840     case NOP_EXPR:
1841       error ("invalid truth-value expression");
1842       return;
1843
1844     case PLUS_EXPR:
1845       opname = "+"; break;
1846     case MINUS_EXPR:
1847       opname = "-"; break;
1848     case MULT_EXPR:
1849       opname = "*"; break;
1850     case MAX_EXPR:
1851       opname = "max"; break;
1852     case MIN_EXPR:
1853       opname = "min"; break;
1854     case EQ_EXPR:
1855       opname = "=="; break;
1856     case NE_EXPR:
1857       opname = "!="; break;
1858     case LE_EXPR:
1859       opname = "<="; break;
1860     case GE_EXPR:
1861       opname = ">="; break;
1862     case LT_EXPR:
1863       opname = "<"; break;
1864     case GT_EXPR:
1865       opname = ">"; break;
1866     case LSHIFT_EXPR:
1867       opname = "<<"; break;
1868     case RSHIFT_EXPR:
1869       opname = ">>"; break;
1870     case TRUNC_MOD_EXPR:
1871     case FLOOR_MOD_EXPR:
1872       opname = "%"; break;
1873     case TRUNC_DIV_EXPR:
1874     case FLOOR_DIV_EXPR:
1875       opname = "/"; break;
1876     case BIT_AND_EXPR:
1877       opname = "&"; break;
1878     case BIT_IOR_EXPR:
1879       opname = "|"; break;
1880     case TRUTH_ANDIF_EXPR:
1881       opname = "&&"; break;
1882     case TRUTH_ORIF_EXPR:
1883       opname = "||"; break;
1884     case BIT_XOR_EXPR:
1885       opname = "^"; break;
1886     default:
1887       gcc_unreachable ();
1888     }
1889   error ("invalid operands to binary %s", opname);
1890 }
1891 \f
1892 /* Subroutine of build_binary_op, used for comparison operations.
1893    See if the operands have both been converted from subword integer types
1894    and, if so, perhaps change them both back to their original type.
1895    This function is also responsible for converting the two operands
1896    to the proper common type for comparison.
1897
1898    The arguments of this function are all pointers to local variables
1899    of build_binary_op: OP0_PTR is &OP0, OP1_PTR is &OP1,
1900    RESTYPE_PTR is &RESULT_TYPE and RESCODE_PTR is &RESULTCODE.
1901
1902    If this function returns nonzero, it means that the comparison has
1903    a constant value.  What this function returns is an expression for
1904    that value.  */
1905
1906 tree
1907 shorten_compare (tree *op0_ptr, tree *op1_ptr, tree *restype_ptr,
1908                  enum tree_code *rescode_ptr)
1909 {
1910   tree type;
1911   tree op0 = *op0_ptr;
1912   tree op1 = *op1_ptr;
1913   int unsignedp0, unsignedp1;
1914   int real1, real2;
1915   tree primop0, primop1;
1916   enum tree_code code = *rescode_ptr;
1917
1918   /* Throw away any conversions to wider types
1919      already present in the operands.  */
1920
1921   primop0 = get_narrower (op0, &unsignedp0);
1922   primop1 = get_narrower (op1, &unsignedp1);
1923
1924   /* Handle the case that OP0 does not *contain* a conversion
1925      but it *requires* conversion to FINAL_TYPE.  */
1926
1927   if (op0 == primop0 && TREE_TYPE (op0) != *restype_ptr)
1928     unsignedp0 = TYPE_UNSIGNED (TREE_TYPE (op0));
1929   if (op1 == primop1 && TREE_TYPE (op1) != *restype_ptr)
1930     unsignedp1 = TYPE_UNSIGNED (TREE_TYPE (op1));
1931
1932   /* If one of the operands must be floated, we cannot optimize.  */
1933   real1 = TREE_CODE (TREE_TYPE (primop0)) == REAL_TYPE;
1934   real2 = TREE_CODE (TREE_TYPE (primop1)) == REAL_TYPE;
1935
1936   /* If first arg is constant, swap the args (changing operation
1937      so value is preserved), for canonicalization.  Don't do this if
1938      the second arg is 0.  */
1939
1940   if (TREE_CONSTANT (primop0)
1941       && !integer_zerop (primop1) && !real_zerop (primop1))
1942     {
1943       tree tem = primop0;
1944       int temi = unsignedp0;
1945       primop0 = primop1;
1946       primop1 = tem;
1947       tem = op0;
1948       op0 = op1;
1949       op1 = tem;
1950       *op0_ptr = op0;
1951       *op1_ptr = op1;
1952       unsignedp0 = unsignedp1;
1953       unsignedp1 = temi;
1954       temi = real1;
1955       real1 = real2;
1956       real2 = temi;
1957
1958       switch (code)
1959         {
1960         case LT_EXPR:
1961           code = GT_EXPR;
1962           break;
1963         case GT_EXPR:
1964           code = LT_EXPR;
1965           break;
1966         case LE_EXPR:
1967           code = GE_EXPR;
1968           break;
1969         case GE_EXPR:
1970           code = LE_EXPR;
1971           break;
1972         default:
1973           break;
1974         }
1975       *rescode_ptr = code;
1976     }
1977
1978   /* If comparing an integer against a constant more bits wide,
1979      maybe we can deduce a value of 1 or 0 independent of the data.
1980      Or else truncate the constant now
1981      rather than extend the variable at run time.
1982
1983      This is only interesting if the constant is the wider arg.
1984      Also, it is not safe if the constant is unsigned and the
1985      variable arg is signed, since in this case the variable
1986      would be sign-extended and then regarded as unsigned.
1987      Our technique fails in this case because the lowest/highest
1988      possible unsigned results don't follow naturally from the
1989      lowest/highest possible values of the variable operand.
1990      For just EQ_EXPR and NE_EXPR there is another technique that
1991      could be used: see if the constant can be faithfully represented
1992      in the other operand's type, by truncating it and reextending it
1993      and see if that preserves the constant's value.  */
1994
1995   if (!real1 && !real2
1996       && TREE_CODE (primop1) == INTEGER_CST
1997       && TYPE_PRECISION (TREE_TYPE (primop0)) < TYPE_PRECISION (*restype_ptr))
1998     {
1999       int min_gt, max_gt, min_lt, max_lt;
2000       tree maxval, minval;
2001       /* 1 if comparison is nominally unsigned.  */
2002       int unsignedp = TYPE_UNSIGNED (*restype_ptr);
2003       tree val;
2004
2005       type = c_common_signed_or_unsigned_type (unsignedp0,
2006                                                TREE_TYPE (primop0));
2007
2008       maxval = TYPE_MAX_VALUE (type);
2009       minval = TYPE_MIN_VALUE (type);
2010
2011       if (unsignedp && !unsignedp0)
2012         *restype_ptr = c_common_signed_type (*restype_ptr);
2013
2014       if (TREE_TYPE (primop1) != *restype_ptr)
2015         {
2016           /* Convert primop1 to target type, but do not introduce
2017              additional overflow.  We know primop1 is an int_cst.  */
2018           tree tmp = build_int_cst_wide (*restype_ptr,
2019                                          TREE_INT_CST_LOW (primop1),
2020                                          TREE_INT_CST_HIGH (primop1));
2021
2022           primop1 = force_fit_type (tmp, 0, TREE_OVERFLOW (primop1),
2023                                     TREE_CONSTANT_OVERFLOW (primop1));
2024         }
2025       if (type != *restype_ptr)
2026         {
2027           minval = convert (*restype_ptr, minval);
2028           maxval = convert (*restype_ptr, maxval);
2029         }
2030
2031       if (unsignedp && unsignedp0)
2032         {
2033           min_gt = INT_CST_LT_UNSIGNED (primop1, minval);
2034           max_gt = INT_CST_LT_UNSIGNED (primop1, maxval);
2035           min_lt = INT_CST_LT_UNSIGNED (minval, primop1);
2036           max_lt = INT_CST_LT_UNSIGNED (maxval, primop1);
2037         }
2038       else
2039         {
2040           min_gt = INT_CST_LT (primop1, minval);
2041           max_gt = INT_CST_LT (primop1, maxval);
2042           min_lt = INT_CST_LT (minval, primop1);
2043           max_lt = INT_CST_LT (maxval, primop1);
2044         }
2045
2046       val = 0;
2047       /* This used to be a switch, but Genix compiler can't handle that.  */
2048       if (code == NE_EXPR)
2049         {
2050           if (max_lt || min_gt)
2051             val = truthvalue_true_node;
2052         }
2053       else if (code == EQ_EXPR)
2054         {
2055           if (max_lt || min_gt)
2056             val = truthvalue_false_node;
2057         }
2058       else if (code == LT_EXPR)
2059         {
2060           if (max_lt)
2061             val = truthvalue_true_node;
2062           if (!min_lt)
2063             val = truthvalue_false_node;
2064         }
2065       else if (code == GT_EXPR)
2066         {
2067           if (min_gt)
2068             val = truthvalue_true_node;
2069           if (!max_gt)
2070             val = truthvalue_false_node;
2071         }
2072       else if (code == LE_EXPR)
2073         {
2074           if (!max_gt)
2075             val = truthvalue_true_node;
2076           if (min_gt)
2077             val = truthvalue_false_node;
2078         }
2079       else if (code == GE_EXPR)
2080         {
2081           if (!min_lt)
2082             val = truthvalue_true_node;
2083           if (max_lt)
2084             val = truthvalue_false_node;
2085         }
2086
2087       /* If primop0 was sign-extended and unsigned comparison specd,
2088          we did a signed comparison above using the signed type bounds.
2089          But the comparison we output must be unsigned.
2090
2091          Also, for inequalities, VAL is no good; but if the signed
2092          comparison had *any* fixed result, it follows that the
2093          unsigned comparison just tests the sign in reverse
2094          (positive values are LE, negative ones GE).
2095          So we can generate an unsigned comparison
2096          against an extreme value of the signed type.  */
2097
2098       if (unsignedp && !unsignedp0)
2099         {
2100           if (val != 0)
2101             switch (code)
2102               {
2103               case LT_EXPR:
2104               case GE_EXPR:
2105                 primop1 = TYPE_MIN_VALUE (type);
2106                 val = 0;
2107                 break;
2108
2109               case LE_EXPR:
2110               case GT_EXPR:
2111                 primop1 = TYPE_MAX_VALUE (type);
2112                 val = 0;
2113                 break;
2114
2115               default:
2116                 break;
2117               }
2118           type = c_common_unsigned_type (type);
2119         }
2120
2121       if (TREE_CODE (primop0) != INTEGER_CST)
2122         {
2123           if (val == truthvalue_false_node)
2124             warning ("comparison is always false due to limited range of data type");
2125           if (val == truthvalue_true_node)
2126             warning ("comparison is always true due to limited range of data type");
2127         }
2128
2129       if (val != 0)
2130         {
2131           /* Don't forget to evaluate PRIMOP0 if it has side effects.  */
2132           if (TREE_SIDE_EFFECTS (primop0))
2133             return build2 (COMPOUND_EXPR, TREE_TYPE (val), primop0, val);
2134           return val;
2135         }
2136
2137       /* Value is not predetermined, but do the comparison
2138          in the type of the operand that is not constant.
2139          TYPE is already properly set.  */
2140     }
2141   else if (real1 && real2
2142            && (TYPE_PRECISION (TREE_TYPE (primop0))
2143                == TYPE_PRECISION (TREE_TYPE (primop1))))
2144     type = TREE_TYPE (primop0);
2145
2146   /* If args' natural types are both narrower than nominal type
2147      and both extend in the same manner, compare them
2148      in the type of the wider arg.
2149      Otherwise must actually extend both to the nominal
2150      common type lest different ways of extending
2151      alter the result.
2152      (eg, (short)-1 == (unsigned short)-1  should be 0.)  */
2153
2154   else if (unsignedp0 == unsignedp1 && real1 == real2
2155            && TYPE_PRECISION (TREE_TYPE (primop0)) < TYPE_PRECISION (*restype_ptr)
2156            && TYPE_PRECISION (TREE_TYPE (primop1)) < TYPE_PRECISION (*restype_ptr))
2157     {
2158       type = common_type (TREE_TYPE (primop0), TREE_TYPE (primop1));
2159       type = c_common_signed_or_unsigned_type (unsignedp0
2160                                                || TYPE_UNSIGNED (*restype_ptr),
2161                                                type);
2162       /* Make sure shorter operand is extended the right way
2163          to match the longer operand.  */
2164       primop0
2165         = convert (c_common_signed_or_unsigned_type (unsignedp0,
2166                                                      TREE_TYPE (primop0)),
2167                    primop0);
2168       primop1
2169         = convert (c_common_signed_or_unsigned_type (unsignedp1,
2170                                                      TREE_TYPE (primop1)),
2171                    primop1);
2172     }
2173   else
2174     {
2175       /* Here we must do the comparison on the nominal type
2176          using the args exactly as we received them.  */
2177       type = *restype_ptr;
2178       primop0 = op0;
2179       primop1 = op1;
2180
2181       if (!real1 && !real2 && integer_zerop (primop1)
2182           && TYPE_UNSIGNED (*restype_ptr))
2183         {
2184           tree value = 0;
2185           switch (code)
2186             {
2187             case GE_EXPR:
2188               /* All unsigned values are >= 0, so we warn if extra warnings
2189                  are requested.  However, if OP0 is a constant that is
2190                  >= 0, the signedness of the comparison isn't an issue,
2191                  so suppress the warning.  */
2192               if (extra_warnings && !in_system_header
2193                   && !(TREE_CODE (primop0) == INTEGER_CST
2194                        && !TREE_OVERFLOW (convert (c_common_signed_type (type),
2195                                                    primop0))))
2196                 warning ("comparison of unsigned expression >= 0 is always true");
2197               value = truthvalue_true_node;
2198               break;
2199
2200             case LT_EXPR:
2201               if (extra_warnings && !in_system_header
2202                   && !(TREE_CODE (primop0) == INTEGER_CST
2203                        && !TREE_OVERFLOW (convert (c_common_signed_type (type),
2204                                                    primop0))))
2205                 warning ("comparison of unsigned expression < 0 is always false");
2206               value = truthvalue_false_node;
2207               break;
2208
2209             default:
2210               break;
2211             }
2212
2213           if (value != 0)
2214             {
2215               /* Don't forget to evaluate PRIMOP0 if it has side effects.  */
2216               if (TREE_SIDE_EFFECTS (primop0))
2217                 return build2 (COMPOUND_EXPR, TREE_TYPE (value),
2218                                primop0, value);
2219               return value;
2220             }
2221         }
2222     }
2223
2224   *op0_ptr = convert (type, primop0);
2225   *op1_ptr = convert (type, primop1);
2226
2227   *restype_ptr = truthvalue_type_node;
2228
2229   return 0;
2230 }
2231 \f
2232 /* Return a tree for the sum or difference (RESULTCODE says which)
2233    of pointer PTROP and integer INTOP.  */
2234
2235 tree
2236 pointer_int_sum (enum tree_code resultcode, tree ptrop, tree intop)
2237 {
2238   tree size_exp;
2239
2240   /* The result is a pointer of the same type that is being added.  */
2241
2242   tree result_type = TREE_TYPE (ptrop);
2243
2244   if (TREE_CODE (TREE_TYPE (result_type)) == VOID_TYPE)
2245     {
2246       if (pedantic || warn_pointer_arith)
2247         pedwarn ("pointer of type %<void *%> used in arithmetic");
2248       size_exp = integer_one_node;
2249     }
2250   else if (TREE_CODE (TREE_TYPE (result_type)) == FUNCTION_TYPE)
2251     {
2252       if (pedantic || warn_pointer_arith)
2253         pedwarn ("pointer to a function used in arithmetic");
2254       size_exp = integer_one_node;
2255     }
2256   else if (TREE_CODE (TREE_TYPE (result_type)) == METHOD_TYPE)
2257     {
2258       if (pedantic || warn_pointer_arith)
2259         pedwarn ("pointer to member function used in arithmetic");
2260       size_exp = integer_one_node;
2261     }
2262   else
2263     size_exp = size_in_bytes (TREE_TYPE (result_type));
2264
2265   /* If what we are about to multiply by the size of the elements
2266      contains a constant term, apply distributive law
2267      and multiply that constant term separately.
2268      This helps produce common subexpressions.  */
2269
2270   if ((TREE_CODE (intop) == PLUS_EXPR || TREE_CODE (intop) == MINUS_EXPR)
2271       && !TREE_CONSTANT (intop)
2272       && TREE_CONSTANT (TREE_OPERAND (intop, 1))
2273       && TREE_CONSTANT (size_exp)
2274       /* If the constant comes from pointer subtraction,
2275          skip this optimization--it would cause an error.  */
2276       && TREE_CODE (TREE_TYPE (TREE_OPERAND (intop, 0))) == INTEGER_TYPE
2277       /* If the constant is unsigned, and smaller than the pointer size,
2278          then we must skip this optimization.  This is because it could cause
2279          an overflow error if the constant is negative but INTOP is not.  */
2280       && (!TYPE_UNSIGNED (TREE_TYPE (intop))
2281           || (TYPE_PRECISION (TREE_TYPE (intop))
2282               == TYPE_PRECISION (TREE_TYPE (ptrop)))))
2283     {
2284       enum tree_code subcode = resultcode;
2285       tree int_type = TREE_TYPE (intop);
2286       if (TREE_CODE (intop) == MINUS_EXPR)
2287         subcode = (subcode == PLUS_EXPR ? MINUS_EXPR : PLUS_EXPR);
2288       /* Convert both subexpression types to the type of intop,
2289          because weird cases involving pointer arithmetic
2290          can result in a sum or difference with different type args.  */
2291       ptrop = build_binary_op (subcode, ptrop,
2292                                convert (int_type, TREE_OPERAND (intop, 1)), 1);
2293       intop = convert (int_type, TREE_OPERAND (intop, 0));
2294     }
2295
2296   /* Convert the integer argument to a type the same size as sizetype
2297      so the multiply won't overflow spuriously.  */
2298
2299   if (TYPE_PRECISION (TREE_TYPE (intop)) != TYPE_PRECISION (sizetype)
2300       || TYPE_UNSIGNED (TREE_TYPE (intop)) != TYPE_UNSIGNED (sizetype))
2301     intop = convert (c_common_type_for_size (TYPE_PRECISION (sizetype),
2302                                              TYPE_UNSIGNED (sizetype)), intop);
2303
2304   /* Replace the integer argument with a suitable product by the object size.
2305      Do this multiplication as signed, then convert to the appropriate
2306      pointer type (actually unsigned integral).  */
2307
2308   intop = convert (result_type,
2309                    build_binary_op (MULT_EXPR, intop,
2310                                     convert (TREE_TYPE (intop), size_exp), 1));
2311
2312   /* Create the sum or difference.  */
2313   return fold (build2 (resultcode, result_type, ptrop, intop));
2314 }
2315 \f
2316 /* Prepare expr to be an argument of a TRUTH_NOT_EXPR,
2317    or validate its data type for an `if' or `while' statement or ?..: exp.
2318
2319    This preparation consists of taking the ordinary
2320    representation of an expression expr and producing a valid tree
2321    boolean expression describing whether expr is nonzero.  We could
2322    simply always do build_binary_op (NE_EXPR, expr, truthvalue_false_node, 1),
2323    but we optimize comparisons, &&, ||, and !.
2324
2325    The resulting type should always be `truthvalue_type_node'.  */
2326
2327 tree
2328 c_common_truthvalue_conversion (tree expr)
2329 {
2330   switch (TREE_CODE (expr))
2331     {
2332     case EQ_EXPR:   case NE_EXPR:   case UNEQ_EXPR: case LTGT_EXPR:
2333     case LE_EXPR:   case GE_EXPR:   case LT_EXPR:   case GT_EXPR:
2334     case UNLE_EXPR: case UNGE_EXPR: case UNLT_EXPR: case UNGT_EXPR:
2335     case ORDERED_EXPR: case UNORDERED_EXPR:
2336       if (TREE_TYPE (expr) == truthvalue_type_node)
2337         return expr;
2338       return build2 (TREE_CODE (expr), truthvalue_type_node,
2339                      TREE_OPERAND (expr, 0), TREE_OPERAND (expr, 1));
2340
2341     case TRUTH_ANDIF_EXPR:
2342     case TRUTH_ORIF_EXPR:
2343     case TRUTH_AND_EXPR:
2344     case TRUTH_OR_EXPR:
2345     case TRUTH_XOR_EXPR:
2346       if (TREE_TYPE (expr) == truthvalue_type_node)
2347         return expr;
2348       return build2 (TREE_CODE (expr), truthvalue_type_node,
2349                  lang_hooks.truthvalue_conversion (TREE_OPERAND (expr, 0)),
2350                  lang_hooks.truthvalue_conversion (TREE_OPERAND (expr, 1)));
2351
2352     case TRUTH_NOT_EXPR:
2353       if (TREE_TYPE (expr) == truthvalue_type_node)
2354         return expr;
2355       return build1 (TREE_CODE (expr), truthvalue_type_node,
2356                  lang_hooks.truthvalue_conversion (TREE_OPERAND (expr, 0)));
2357
2358     case ERROR_MARK:
2359       return expr;
2360
2361     case INTEGER_CST:
2362       /* Avoid integer_zerop to ignore TREE_CONSTANT_OVERFLOW.  */
2363       return (TREE_INT_CST_LOW (expr) != 0 || TREE_INT_CST_HIGH (expr) != 0)
2364              ? truthvalue_true_node
2365              : truthvalue_false_node;
2366
2367     case REAL_CST:
2368       return real_compare (NE_EXPR, &TREE_REAL_CST (expr), &dconst0)
2369              ? truthvalue_true_node
2370              : truthvalue_false_node;
2371
2372     case FUNCTION_DECL:
2373       expr = build_unary_op (ADDR_EXPR, expr, 0);
2374       /* Fall through.  */
2375
2376     case ADDR_EXPR:
2377       {
2378         if (TREE_CODE (TREE_OPERAND (expr, 0)) == FUNCTION_DECL
2379             && !DECL_WEAK (TREE_OPERAND (expr, 0)))
2380           {
2381             /* Common Ada/Pascal programmer's mistake.  We always warn
2382                about this since it is so bad.  */
2383             warning ("the address of %qD, will always evaluate as %<true%>",
2384                      TREE_OPERAND (expr, 0));
2385             return truthvalue_true_node;
2386           }
2387
2388         /* If we are taking the address of an external decl, it might be
2389            zero if it is weak, so we cannot optimize.  */
2390         if (DECL_P (TREE_OPERAND (expr, 0))
2391             && DECL_EXTERNAL (TREE_OPERAND (expr, 0)))
2392           break;
2393
2394         if (TREE_SIDE_EFFECTS (TREE_OPERAND (expr, 0)))
2395           return build2 (COMPOUND_EXPR, truthvalue_type_node,
2396                          TREE_OPERAND (expr, 0), truthvalue_true_node);
2397         else
2398           return truthvalue_true_node;
2399       }
2400
2401     case COMPLEX_EXPR:
2402       return build_binary_op ((TREE_SIDE_EFFECTS (TREE_OPERAND (expr, 1))
2403                                ? TRUTH_OR_EXPR : TRUTH_ORIF_EXPR),
2404                 lang_hooks.truthvalue_conversion (TREE_OPERAND (expr, 0)),
2405                 lang_hooks.truthvalue_conversion (TREE_OPERAND (expr, 1)),
2406                               0);
2407
2408     case NEGATE_EXPR:
2409     case ABS_EXPR:
2410     case FLOAT_EXPR:
2411       /* These don't change whether an object is nonzero or zero.  */
2412       return lang_hooks.truthvalue_conversion (TREE_OPERAND (expr, 0));
2413
2414     case LROTATE_EXPR:
2415     case RROTATE_EXPR:
2416       /* These don't change whether an object is zero or nonzero, but
2417          we can't ignore them if their second arg has side-effects.  */
2418       if (TREE_SIDE_EFFECTS (TREE_OPERAND (expr, 1)))
2419         return build2 (COMPOUND_EXPR, truthvalue_type_node,
2420                        TREE_OPERAND (expr, 1),
2421                        lang_hooks.truthvalue_conversion (TREE_OPERAND (expr, 0)));
2422       else
2423         return lang_hooks.truthvalue_conversion (TREE_OPERAND (expr, 0));
2424
2425     case COND_EXPR:
2426       /* Distribute the conversion into the arms of a COND_EXPR.  */
2427       return fold (build3 (COND_EXPR, truthvalue_type_node,
2428                 TREE_OPERAND (expr, 0),
2429                 lang_hooks.truthvalue_conversion (TREE_OPERAND (expr, 1)),
2430                 lang_hooks.truthvalue_conversion (TREE_OPERAND (expr, 2))));
2431
2432     case CONVERT_EXPR:
2433       /* Don't cancel the effect of a CONVERT_EXPR from a REFERENCE_TYPE,
2434          since that affects how `default_conversion' will behave.  */
2435       if (TREE_CODE (TREE_TYPE (expr)) == REFERENCE_TYPE
2436           || TREE_CODE (TREE_TYPE (TREE_OPERAND (expr, 0))) == REFERENCE_TYPE)
2437         break;
2438       /* Fall through....  */
2439     case NOP_EXPR:
2440       /* If this is widening the argument, we can ignore it.  */
2441       if (TYPE_PRECISION (TREE_TYPE (expr))
2442           >= TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (expr, 0))))
2443         return lang_hooks.truthvalue_conversion (TREE_OPERAND (expr, 0));
2444       break;
2445
2446     case MINUS_EXPR:
2447       /* Perhaps reduce (x - y) != 0 to (x != y).  The expressions
2448          aren't guaranteed to the be same for modes that can represent
2449          infinity, since if x and y are both +infinity, or both
2450          -infinity, then x - y is not a number.
2451
2452          Note that this transformation is safe when x or y is NaN.
2453          (x - y) is then NaN, and both (x - y) != 0 and x != y will
2454          be false.  */
2455       if (HONOR_INFINITIES (TYPE_MODE (TREE_TYPE (TREE_OPERAND (expr, 0)))))
2456         break;
2457       /* Fall through....  */
2458     case BIT_XOR_EXPR:
2459       /* This and MINUS_EXPR can be changed into a comparison of the
2460          two objects.  */
2461       if (TREE_TYPE (TREE_OPERAND (expr, 0))
2462           == TREE_TYPE (TREE_OPERAND (expr, 1)))
2463         return build_binary_op (NE_EXPR, TREE_OPERAND (expr, 0),
2464                                 TREE_OPERAND (expr, 1), 1);
2465       return build_binary_op (NE_EXPR, TREE_OPERAND (expr, 0),
2466                               fold (build1 (NOP_EXPR,
2467                                             TREE_TYPE (TREE_OPERAND (expr, 0)),
2468                                             TREE_OPERAND (expr, 1))), 1);
2469
2470     case BIT_AND_EXPR:
2471       if (integer_onep (TREE_OPERAND (expr, 1))
2472           && TREE_TYPE (expr) != truthvalue_type_node)
2473         /* Using convert here would cause infinite recursion.  */
2474         return build1 (NOP_EXPR, truthvalue_type_node, expr);
2475       break;
2476
2477     case MODIFY_EXPR:
2478       if (warn_parentheses && !TREE_NO_WARNING (expr))
2479         warning ("suggest parentheses around assignment used as truth value");
2480       break;
2481
2482     default:
2483       break;
2484     }
2485
2486   if (TREE_CODE (TREE_TYPE (expr)) == COMPLEX_TYPE)
2487     {
2488       tree t = save_expr (expr);
2489       return (build_binary_op
2490               ((TREE_SIDE_EFFECTS (expr)
2491                 ? TRUTH_OR_EXPR : TRUTH_ORIF_EXPR),
2492         lang_hooks.truthvalue_conversion (build_unary_op (REALPART_EXPR, t, 0)),
2493         lang_hooks.truthvalue_conversion (build_unary_op (IMAGPART_EXPR, t, 0)),
2494                0));
2495     }
2496
2497   return build_binary_op (NE_EXPR, expr, integer_zero_node, 1);
2498 }
2499 \f
2500 static tree builtin_function_2 (const char *builtin_name, const char *name,
2501                                 tree builtin_type, tree type,
2502                                 enum built_in_function function_code,
2503                                 enum built_in_class cl, int library_name_p,
2504                                 bool nonansi_p,
2505                                 tree attrs);
2506
2507 /* Make a variant type in the proper way for C/C++, propagating qualifiers
2508    down to the element type of an array.  */
2509
2510 tree
2511 c_build_qualified_type (tree type, int type_quals)
2512 {
2513   if (type == error_mark_node)
2514     return type;
2515
2516   if (TREE_CODE (type) == ARRAY_TYPE)
2517     {
2518       tree t;
2519       tree element_type = c_build_qualified_type (TREE_TYPE (type),
2520                                                   type_quals);
2521
2522       /* See if we already have an identically qualified type.  */
2523       for (t = TYPE_MAIN_VARIANT (type); t; t = TYPE_NEXT_VARIANT (t))
2524         {
2525           if (TYPE_QUALS (strip_array_types (t)) == type_quals
2526               && TYPE_NAME (t) == TYPE_NAME (type)
2527               && TYPE_CONTEXT (t) == TYPE_CONTEXT (type)
2528               && attribute_list_equal (TYPE_ATTRIBUTES (t),
2529                                        TYPE_ATTRIBUTES (type)))
2530             break;
2531         }
2532       if (!t)
2533         {
2534           t = build_variant_type_copy (type);
2535           TREE_TYPE (t) = element_type;
2536         }
2537       return t;
2538     }
2539
2540   /* A restrict-qualified pointer type must be a pointer to object or
2541      incomplete type.  Note that the use of POINTER_TYPE_P also allows
2542      REFERENCE_TYPEs, which is appropriate for C++.  */
2543   if ((type_quals & TYPE_QUAL_RESTRICT)
2544       && (!POINTER_TYPE_P (type)
2545           || !C_TYPE_OBJECT_OR_INCOMPLETE_P (TREE_TYPE (type))))
2546     {
2547       error ("invalid use of %<restrict%>");
2548       type_quals &= ~TYPE_QUAL_RESTRICT;
2549     }
2550
2551   return build_qualified_type (type, type_quals);
2552 }
2553
2554 /* Apply the TYPE_QUALS to the new DECL.  */
2555
2556 void
2557 c_apply_type_quals_to_decl (int type_quals, tree decl)
2558 {
2559   tree type = TREE_TYPE (decl);
2560
2561   if (type == error_mark_node)
2562     return;
2563
2564   if (((type_quals & TYPE_QUAL_CONST)
2565        || (type && TREE_CODE (type) == REFERENCE_TYPE))
2566       /* An object declared 'const' is only readonly after it is
2567          initialized.  We don't have any way of expressing this currently,
2568          so we need to be conservative and unset TREE_READONLY for types
2569          with constructors.  Otherwise aliasing code will ignore stores in
2570          an inline constructor.  */
2571       && !(type && TYPE_NEEDS_CONSTRUCTING (type)))
2572     TREE_READONLY (decl) = 1;
2573   if (type_quals & TYPE_QUAL_VOLATILE)
2574     {
2575       TREE_SIDE_EFFECTS (decl) = 1;
2576       TREE_THIS_VOLATILE (decl) = 1;
2577     }
2578   if (type_quals & TYPE_QUAL_RESTRICT)
2579     {
2580       while (type && TREE_CODE (type) == ARRAY_TYPE)
2581         /* Allow 'restrict' on arrays of pointers.
2582            FIXME currently we just ignore it.  */
2583         type = TREE_TYPE (type);
2584       if (!type
2585           || !POINTER_TYPE_P (type)
2586           || !C_TYPE_OBJECT_OR_INCOMPLETE_P (TREE_TYPE (type)))
2587         error ("invalid use of %<restrict%>");
2588       else if (flag_strict_aliasing && type == TREE_TYPE (decl))
2589         /* Indicate we need to make a unique alias set for this pointer.
2590            We can't do it here because it might be pointing to an
2591            incomplete type.  */
2592         DECL_POINTER_ALIAS_SET (decl) = -2;
2593     }
2594 }
2595
2596 /* Hash function for the problem of multiple type definitions in
2597    different files.  This must hash all types that will compare
2598    equal via comptypes to the same value.  In practice it hashes
2599    on some of the simple stuff and leaves the details to comptypes.  */
2600
2601 static hashval_t
2602 c_type_hash (const void *p)
2603 {
2604   int i = 0;
2605   int shift, size;
2606   tree t = (tree) p;
2607   tree t2;
2608   switch (TREE_CODE (t))
2609     {
2610     /* For pointers, hash on pointee type plus some swizzling.  */
2611     case POINTER_TYPE:
2612       return c_type_hash (TREE_TYPE (t)) ^ 0x3003003;
2613     /* Hash on number of elements and total size.  */
2614     case ENUMERAL_TYPE:
2615       shift = 3;
2616       t2 = TYPE_VALUES (t);
2617       break;
2618     case RECORD_TYPE:
2619       shift = 0;
2620       t2 = TYPE_FIELDS (t);
2621       break;
2622     case QUAL_UNION_TYPE:
2623       shift = 1;
2624       t2 = TYPE_FIELDS (t);
2625       break;
2626     case UNION_TYPE:
2627       shift = 2;
2628       t2 = TYPE_FIELDS (t);
2629       break;
2630     default:
2631       gcc_unreachable ();
2632     }
2633   for (; t2; t2 = TREE_CHAIN (t2))
2634     i++;
2635   size = TREE_INT_CST_LOW (TYPE_SIZE (t));
2636   return ((size << 24) | (i << shift));
2637 }
2638
2639 static GTY((param_is (union tree_node))) htab_t type_hash_table;
2640
2641 /* Return the typed-based alias set for T, which may be an expression
2642    or a type.  Return -1 if we don't do anything special.  */
2643
2644 HOST_WIDE_INT
2645 c_common_get_alias_set (tree t)
2646 {
2647   tree u;
2648   PTR *slot;
2649
2650   /* Permit type-punning when accessing a union, provided the access
2651      is directly through the union.  For example, this code does not
2652      permit taking the address of a union member and then storing
2653      through it.  Even the type-punning allowed here is a GCC
2654      extension, albeit a common and useful one; the C standard says
2655      that such accesses have implementation-defined behavior.  */
2656   for (u = t;
2657        TREE_CODE (u) == COMPONENT_REF || TREE_CODE (u) == ARRAY_REF;
2658        u = TREE_OPERAND (u, 0))
2659     if (TREE_CODE (u) == COMPONENT_REF
2660         && TREE_CODE (TREE_TYPE (TREE_OPERAND (u, 0))) == UNION_TYPE)
2661       return 0;
2662
2663   /* That's all the expressions we handle specially.  */
2664   if (!TYPE_P (t))
2665     return -1;
2666
2667   /* The C standard guarantees that any object may be accessed via an
2668      lvalue that has character type.  */
2669   if (t == char_type_node
2670       || t == signed_char_type_node
2671       || t == unsigned_char_type_node)
2672     return 0;
2673
2674   /* If it has the may_alias attribute, it can alias anything.  */
2675   if (lookup_attribute ("may_alias", TYPE_ATTRIBUTES (t)))
2676     return 0;
2677
2678   /* The C standard specifically allows aliasing between signed and
2679      unsigned variants of the same type.  We treat the signed
2680      variant as canonical.  */
2681   if (TREE_CODE (t) == INTEGER_TYPE && TYPE_UNSIGNED (t))
2682     {
2683       tree t1 = c_common_signed_type (t);
2684
2685       /* t1 == t can happen for boolean nodes which are always unsigned.  */
2686       if (t1 != t)
2687         return get_alias_set (t1);
2688     }
2689   else if (POINTER_TYPE_P (t))
2690     {
2691       tree t1;
2692
2693       /* Unfortunately, there is no canonical form of a pointer type.
2694          In particular, if we have `typedef int I', then `int *', and
2695          `I *' are different types.  So, we have to pick a canonical
2696          representative.  We do this below.
2697
2698          Technically, this approach is actually more conservative that
2699          it needs to be.  In particular, `const int *' and `int *'
2700          should be in different alias sets, according to the C and C++
2701          standard, since their types are not the same, and so,
2702          technically, an `int **' and `const int **' cannot point at
2703          the same thing.
2704
2705          But, the standard is wrong.  In particular, this code is
2706          legal C++:
2707
2708             int *ip;
2709             int **ipp = &ip;
2710             const int* const* cipp = ipp;
2711
2712          And, it doesn't make sense for that to be legal unless you
2713          can dereference IPP and CIPP.  So, we ignore cv-qualifiers on
2714          the pointed-to types.  This issue has been reported to the
2715          C++ committee.  */
2716       t1 = build_type_no_quals (t);
2717       if (t1 != t)
2718         return get_alias_set (t1);
2719     }
2720
2721   /* Handle the case of multiple type nodes referring to "the same" type,
2722      which occurs with IMA.  These share an alias set.  FIXME:  Currently only
2723      C90 is handled.  (In C99 type compatibility is not transitive, which
2724      complicates things mightily. The alias set splay trees can theoretically
2725      represent this, but insertion is tricky when you consider all the
2726      different orders things might arrive in.) */
2727
2728   if (c_language != clk_c || flag_isoc99)
2729     return -1;
2730
2731   /* Save time if there's only one input file.  */
2732   if (num_in_fnames == 1)
2733     return -1;
2734
2735   /* Pointers need special handling if they point to any type that
2736      needs special handling (below).  */
2737   if (TREE_CODE (t) == POINTER_TYPE)
2738     {
2739       tree t2;
2740       /* Find bottom type under any nested POINTERs.  */
2741       for (t2 = TREE_TYPE (t);
2742      TREE_CODE (t2) == POINTER_TYPE;
2743      t2 = TREE_TYPE (t2))
2744   ;
2745       if (TREE_CODE (t2) != RECORD_TYPE
2746     && TREE_CODE (t2) != ENUMERAL_TYPE
2747     && TREE_CODE (t2) != QUAL_UNION_TYPE
2748     && TREE_CODE (t2) != UNION_TYPE)
2749   return -1;
2750       if (TYPE_SIZE (t2) == 0)
2751   return -1;
2752     }
2753   /* These are the only cases that need special handling.  */
2754   if (TREE_CODE (t) != RECORD_TYPE
2755       && TREE_CODE (t) != ENUMERAL_TYPE
2756       && TREE_CODE (t) != QUAL_UNION_TYPE
2757       && TREE_CODE (t) != UNION_TYPE
2758       && TREE_CODE (t) != POINTER_TYPE)
2759     return -1;
2760   /* Undefined? */
2761   if (TYPE_SIZE (t) == 0)
2762     return -1;
2763
2764   /* Look up t in hash table.  Only one of the compatible types within each
2765      alias set is recorded in the table.  */
2766   if (!type_hash_table)
2767     type_hash_table = htab_create_ggc (1021, c_type_hash,
2768             (htab_eq) lang_hooks.types_compatible_p,
2769             NULL);
2770   slot = htab_find_slot (type_hash_table, t, INSERT);
2771   if (*slot != NULL)
2772     {
2773       TYPE_ALIAS_SET (t) = TYPE_ALIAS_SET ((tree)*slot);
2774       return TYPE_ALIAS_SET ((tree)*slot);
2775     }
2776   else
2777     /* Our caller will assign and record (in t) a new alias set; all we need
2778        to do is remember t in the hash table.  */
2779     *slot = t;
2780
2781   return -1;
2782 }
2783 \f
2784 /* Compute the value of 'sizeof (TYPE)' or '__alignof__ (TYPE)', where the
2785    second parameter indicates which OPERATOR is being applied.  The COMPLAIN
2786    flag controls whether we should diagnose possibly ill-formed
2787    constructs or not.  */
2788 tree
2789 c_sizeof_or_alignof_type (tree type, enum tree_code op, int complain)
2790 {
2791   const char *op_name;
2792   tree value = NULL;
2793   enum tree_code type_code = TREE_CODE (type);
2794
2795   gcc_assert (op == SIZEOF_EXPR || op == ALIGNOF_EXPR);
2796   op_name = op == SIZEOF_EXPR ? "sizeof" : "__alignof__";
2797
2798   if (type_code == FUNCTION_TYPE)
2799     {
2800       if (op == SIZEOF_EXPR)
2801         {
2802           if (complain && (pedantic || warn_pointer_arith))
2803             pedwarn ("invalid application of %<sizeof%> to a function type");
2804           value = size_one_node;
2805         }
2806       else
2807         value = size_int (FUNCTION_BOUNDARY / BITS_PER_UNIT);
2808     }
2809   else if (type_code == VOID_TYPE || type_code == ERROR_MARK)
2810     {
2811       if (type_code == VOID_TYPE
2812           && complain && (pedantic || warn_pointer_arith))
2813         pedwarn ("invalid application of %qs to a void type", op_name);
2814       value = size_one_node;
2815     }
2816   else if (!COMPLETE_TYPE_P (type))
2817     {
2818       if (complain)
2819         error ("invalid application of %qs to incomplete type %qT ",
2820                op_name, type);
2821       value = size_zero_node;
2822     }
2823   else
2824     {
2825       if (op == (enum tree_code) SIZEOF_EXPR)
2826         /* Convert in case a char is more than one unit.  */
2827         value = size_binop (CEIL_DIV_EXPR, TYPE_SIZE_UNIT (type),
2828                             size_int (TYPE_PRECISION (char_type_node)
2829                                       / BITS_PER_UNIT));
2830       else
2831         value = size_int (TYPE_ALIGN_UNIT (type));
2832     }
2833
2834   /* VALUE will have an integer type with TYPE_IS_SIZETYPE set.
2835      TYPE_IS_SIZETYPE means that certain things (like overflow) will
2836      never happen.  However, this node should really have type
2837      `size_t', which is just a typedef for an ordinary integer type.  */
2838   value = fold (build1 (NOP_EXPR, size_type_node, value));
2839   gcc_assert (!TYPE_IS_SIZETYPE (TREE_TYPE (value)));
2840
2841   return value;
2842 }
2843
2844 /* Implement the __alignof keyword: Return the minimum required
2845    alignment of EXPR, measured in bytes.  For VAR_DECL's and
2846    FIELD_DECL's return DECL_ALIGN (which can be set from an
2847    "aligned" __attribute__ specification).  */
2848
2849 tree
2850 c_alignof_expr (tree expr)
2851 {
2852   tree t;
2853
2854   if (TREE_CODE (expr) == VAR_DECL)
2855     t = size_int (DECL_ALIGN_UNIT (expr));
2856
2857   else if (TREE_CODE (expr) == COMPONENT_REF
2858            && DECL_C_BIT_FIELD (TREE_OPERAND (expr, 1)))
2859     {
2860       error ("%<__alignof%> applied to a bit-field");
2861       t = size_one_node;
2862     }
2863   else if (TREE_CODE (expr) == COMPONENT_REF
2864            && TREE_CODE (TREE_OPERAND (expr, 1)) == FIELD_DECL)
2865     t = size_int (DECL_ALIGN_UNIT (TREE_OPERAND (expr, 1)));
2866
2867   else if (TREE_CODE (expr) == INDIRECT_REF)
2868     {
2869       tree t = TREE_OPERAND (expr, 0);
2870       tree best = t;
2871       int bestalign = TYPE_ALIGN (TREE_TYPE (TREE_TYPE (t)));
2872
2873       while (TREE_CODE (t) == NOP_EXPR
2874              && TREE_CODE (TREE_TYPE (TREE_OPERAND (t, 0))) == POINTER_TYPE)
2875         {
2876           int thisalign;
2877
2878           t = TREE_OPERAND (t, 0);
2879           thisalign = TYPE_ALIGN (TREE_TYPE (TREE_TYPE (t)));
2880           if (thisalign > bestalign)
2881             best = t, bestalign = thisalign;
2882         }
2883       return c_alignof (TREE_TYPE (TREE_TYPE (best)));
2884     }
2885   else
2886     return c_alignof (TREE_TYPE (expr));
2887
2888   return fold (build1 (NOP_EXPR, size_type_node, t));
2889 }
2890 \f
2891 /* Handle C and C++ default attributes.  */
2892
2893 enum built_in_attribute
2894 {
2895 #define DEF_ATTR_NULL_TREE(ENUM) ENUM,
2896 #define DEF_ATTR_INT(ENUM, VALUE) ENUM,
2897 #define DEF_ATTR_IDENT(ENUM, STRING) ENUM,
2898 #define DEF_ATTR_TREE_LIST(ENUM, PURPOSE, VALUE, CHAIN) ENUM,
2899 #include "builtin-attrs.def"
2900 #undef DEF_ATTR_NULL_TREE
2901 #undef DEF_ATTR_INT
2902 #undef DEF_ATTR_IDENT
2903 #undef DEF_ATTR_TREE_LIST
2904   ATTR_LAST
2905 };
2906
2907 static GTY(()) tree built_in_attributes[(int) ATTR_LAST];
2908
2909 static void c_init_attributes (void);
2910
2911 /* Build tree nodes and builtin functions common to both C and C++ language
2912    frontends.  */
2913
2914 void
2915 c_common_nodes_and_builtins (void)
2916 {
2917   enum builtin_type
2918   {
2919 #define DEF_PRIMITIVE_TYPE(NAME, VALUE) NAME,
2920 #define DEF_FUNCTION_TYPE_0(NAME, RETURN) NAME,
2921 #define DEF_FUNCTION_TYPE_1(NAME, RETURN, ARG1) NAME,
2922 #define DEF_FUNCTION_TYPE_2(NAME, RETURN, ARG1, ARG2) NAME,
2923 #define DEF_FUNCTION_TYPE_3(NAME, RETURN, ARG1, ARG2, ARG3) NAME,
2924 #define DEF_FUNCTION_TYPE_4(NAME, RETURN, ARG1, ARG2, ARG3, ARG4) NAME,
2925 #define DEF_FUNCTION_TYPE_VAR_0(NAME, RETURN) NAME,
2926 #define DEF_FUNCTION_TYPE_VAR_1(NAME, RETURN, ARG1) NAME,
2927 #define DEF_FUNCTION_TYPE_VAR_2(NAME, RETURN, ARG1, ARG2) NAME,
2928 #define DEF_FUNCTION_TYPE_VAR_3(NAME, RETURN, ARG1, ARG2, ARG3) NAME,
2929 #define DEF_POINTER_TYPE(NAME, TYPE) NAME,
2930 #include "builtin-types.def"
2931 #undef DEF_PRIMITIVE_TYPE
2932 #undef DEF_FUNCTION_TYPE_0
2933 #undef DEF_FUNCTION_TYPE_1
2934 #undef DEF_FUNCTION_TYPE_2
2935 #undef DEF_FUNCTION_TYPE_3
2936 #undef DEF_FUNCTION_TYPE_4
2937 #undef DEF_FUNCTION_TYPE_VAR_0
2938 #undef DEF_FUNCTION_TYPE_VAR_1
2939 #undef DEF_FUNCTION_TYPE_VAR_2
2940 #undef DEF_FUNCTION_TYPE_VAR_3
2941 #undef DEF_POINTER_TYPE
2942     BT_LAST
2943   };
2944
2945   typedef enum builtin_type builtin_type;
2946
2947   tree builtin_types[(int) BT_LAST];
2948   int wchar_type_size;
2949   tree array_domain_type;
2950   tree va_list_ref_type_node;
2951   tree va_list_arg_type_node;
2952
2953   /* Define `int' and `char' first so that dbx will output them first.  */
2954   record_builtin_type (RID_INT, NULL, integer_type_node);
2955   record_builtin_type (RID_CHAR, "char", char_type_node);
2956
2957   /* `signed' is the same as `int'.  FIXME: the declarations of "signed",
2958      "unsigned long", "long long unsigned" and "unsigned short" were in C++
2959      but not C.  Are the conditionals here needed?  */
2960   if (c_dialect_cxx ())
2961     record_builtin_type (RID_SIGNED, NULL, integer_type_node);
2962   record_builtin_type (RID_LONG, "long int", long_integer_type_node);
2963   record_builtin_type (RID_UNSIGNED, "unsigned int", unsigned_type_node);
2964   record_builtin_type (RID_MAX, "long unsigned int",
2965                        long_unsigned_type_node);
2966   if (c_dialect_cxx ())
2967     record_builtin_type (RID_MAX, "unsigned long", long_unsigned_type_node);
2968   record_builtin_type (RID_MAX, "long long int",
2969                        long_long_integer_type_node);
2970   record_builtin_type (RID_MAX, "long long unsigned int",
2971                        long_long_unsigned_type_node);
2972   if (c_dialect_cxx ())
2973     record_builtin_type (RID_MAX, "long long unsigned",
2974                          long_long_unsigned_type_node);
2975   record_builtin_type (RID_SHORT, "short int", short_integer_type_node);
2976   record_builtin_type (RID_MAX, "short unsigned int",
2977                        short_unsigned_type_node);
2978   if (c_dialect_cxx ())
2979     record_builtin_type (RID_MAX, "unsigned short",
2980                          short_unsigned_type_node);
2981
2982   /* Define both `signed char' and `unsigned char'.  */
2983   record_builtin_type (RID_MAX, "signed char", signed_char_type_node);
2984   record_builtin_type (RID_MAX, "unsigned char", unsigned_char_type_node);
2985
2986   /* These are types that c_common_type_for_size and
2987      c_common_type_for_mode use.  */
2988   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
2989                                          intQI_type_node));
2990   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
2991                                          intHI_type_node));
2992   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
2993                                          intSI_type_node));
2994   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
2995                                          intDI_type_node));
2996 #if HOST_BITS_PER_WIDE_INT >= 64
2997   if (targetm.scalar_mode_supported_p (TImode))
2998     lang_hooks.decls.pushdecl (build_decl (TYPE_DECL,
2999                                            get_identifier ("__int128_t"),
3000                                            intTI_type_node));
3001 #endif
3002   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
3003                                          unsigned_intQI_type_node));
3004   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
3005                                          unsigned_intHI_type_node));
3006   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
3007                                          unsigned_intSI_type_node));
3008   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
3009                                          unsigned_intDI_type_node));
3010 #if HOST_BITS_PER_WIDE_INT >= 64
3011   if (targetm.scalar_mode_supported_p (TImode))
3012     lang_hooks.decls.pushdecl (build_decl (TYPE_DECL,
3013                                            get_identifier ("__uint128_t"),
3014                                            unsigned_intTI_type_node));
3015 #endif
3016
3017   /* Create the widest literal types.  */
3018   widest_integer_literal_type_node
3019     = make_signed_type (HOST_BITS_PER_WIDE_INT * 2);
3020   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
3021                                          widest_integer_literal_type_node));
3022
3023   widest_unsigned_literal_type_node
3024     = make_unsigned_type (HOST_BITS_PER_WIDE_INT * 2);
3025   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
3026                                          widest_unsigned_literal_type_node));
3027
3028   /* `unsigned long' is the standard type for sizeof.
3029      Note that stddef.h uses `unsigned long',
3030      and this must agree, even if long and int are the same size.  */
3031   size_type_node =
3032     TREE_TYPE (identifier_global_value (get_identifier (SIZE_TYPE)));
3033   signed_size_type_node = c_common_signed_type (size_type_node);
3034   set_sizetype (size_type_node);
3035
3036   pid_type_node =
3037     TREE_TYPE (identifier_global_value (get_identifier (PID_TYPE)));
3038
3039   build_common_tree_nodes_2 (flag_short_double);
3040
3041   record_builtin_type (RID_FLOAT, NULL, float_type_node);
3042   record_builtin_type (RID_DOUBLE, NULL, double_type_node);
3043   record_builtin_type (RID_MAX, "long double", long_double_type_node);
3044
3045   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL,
3046                                          get_identifier ("complex int"),
3047                                          complex_integer_type_node));
3048   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL,
3049                                          get_identifier ("complex float"),
3050                                          complex_float_type_node));
3051   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL,
3052                                          get_identifier ("complex double"),
3053                                          complex_double_type_node));
3054   lang_hooks.decls.pushdecl
3055     (build_decl (TYPE_DECL, get_identifier ("complex long double"),
3056                  complex_long_double_type_node));
3057
3058   if (c_dialect_cxx ())
3059     /* For C++, make fileptr_type_node a distinct void * type until
3060        FILE type is defined.  */
3061     fileptr_type_node = build_variant_type_copy (ptr_type_node);
3062
3063   record_builtin_type (RID_VOID, NULL, void_type_node);
3064
3065   /* This node must not be shared.  */
3066   void_zero_node = make_node (INTEGER_CST);
3067   TREE_TYPE (void_zero_node) = void_type_node;
3068
3069   void_list_node = build_void_list_node ();
3070
3071   /* Make a type to be the domain of a few array types
3072      whose domains don't really matter.
3073      200 is small enough that it always fits in size_t
3074      and large enough that it can hold most function names for the
3075      initializations of __FUNCTION__ and __PRETTY_FUNCTION__.  */
3076   array_domain_type = build_index_type (size_int (200));
3077
3078   /* Make a type for arrays of characters.
3079      With luck nothing will ever really depend on the length of this
3080      array type.  */
3081   char_array_type_node
3082     = build_array_type (char_type_node, array_domain_type);
3083
3084   /* Likewise for arrays of ints.  */
3085   int_array_type_node
3086     = build_array_type (integer_type_node, array_domain_type);
3087
3088   string_type_node = build_pointer_type (char_type_node);
3089   const_string_type_node
3090     = build_pointer_type (build_qualified_type
3091                           (char_type_node, TYPE_QUAL_CONST));
3092
3093   /* This is special for C++ so functions can be overloaded.  */
3094   wchar_type_node = get_identifier (MODIFIED_WCHAR_TYPE);
3095   wchar_type_node = TREE_TYPE (identifier_global_value (wchar_type_node));
3096   wchar_type_size = TYPE_PRECISION (wchar_type_node);
3097   if (c_dialect_cxx ())
3098     {
3099       if (TYPE_UNSIGNED (wchar_type_node))
3100         wchar_type_node = make_unsigned_type (wchar_type_size);
3101       else
3102         wchar_type_node = make_signed_type (wchar_type_size);
3103       record_builtin_type (RID_WCHAR, "wchar_t", wchar_type_node);
3104     }
3105   else
3106     {
3107       signed_wchar_type_node = c_common_signed_type (wchar_type_node);
3108       unsigned_wchar_type_node = c_common_unsigned_type (wchar_type_node);
3109     }
3110
3111   /* This is for wide string constants.  */
3112   wchar_array_type_node
3113     = build_array_type (wchar_type_node, array_domain_type);
3114
3115   wint_type_node =
3116     TREE_TYPE (identifier_global_value (get_identifier (WINT_TYPE)));
3117
3118   intmax_type_node =
3119     TREE_TYPE (identifier_global_value (get_identifier (INTMAX_TYPE)));
3120   uintmax_type_node =
3121     TREE_TYPE (identifier_global_value (get_identifier (UINTMAX_TYPE)));
3122
3123   default_function_type = build_function_type (integer_type_node, NULL_TREE);
3124   ptrdiff_type_node
3125     = TREE_TYPE (identifier_global_value (get_identifier (PTRDIFF_TYPE)));
3126   unsigned_ptrdiff_type_node = c_common_unsigned_type (ptrdiff_type_node);
3127
3128   lang_hooks.decls.pushdecl
3129     (build_decl (TYPE_DECL, get_identifier ("__builtin_va_list"),
3130                  va_list_type_node));
3131
3132   if (TREE_CODE (va_list_type_node) == ARRAY_TYPE)
3133     {
3134       va_list_arg_type_node = va_list_ref_type_node =
3135         build_pointer_type (TREE_TYPE (va_list_type_node));
3136     }
3137   else
3138     {
3139       va_list_arg_type_node = va_list_type_node;
3140       va_list_ref_type_node = build_reference_type (va_list_type_node);
3141     }
3142
3143 #define DEF_PRIMITIVE_TYPE(ENUM, VALUE) \
3144   builtin_types[(int) ENUM] = VALUE;
3145 #define DEF_FUNCTION_TYPE_0(ENUM, RETURN)               \
3146   builtin_types[(int) ENUM]                             \
3147     = build_function_type (builtin_types[(int) RETURN], \
3148                            void_list_node);
3149 #define DEF_FUNCTION_TYPE_1(ENUM, RETURN, ARG1)                         \
3150   builtin_types[(int) ENUM]                                             \
3151     = build_function_type (builtin_types[(int) RETURN],                 \
3152                            tree_cons (NULL_TREE,                        \
3153                                       builtin_types[(int) ARG1],        \
3154                                       void_list_node));
3155 #define DEF_FUNCTION_TYPE_2(ENUM, RETURN, ARG1, ARG2)   \
3156   builtin_types[(int) ENUM]                             \
3157     = build_function_type                               \
3158       (builtin_types[(int) RETURN],                     \
3159        tree_cons (NULL_TREE,                            \
3160                   builtin_types[(int) ARG1],            \
3161                   tree_cons (NULL_TREE,                 \
3162                              builtin_types[(int) ARG2], \
3163                              void_list_node)));
3164 #define DEF_FUNCTION_TYPE_3(ENUM, RETURN, ARG1, ARG2, ARG3)              \
3165   builtin_types[(int) ENUM]                                              \
3166     = build_function_type                                                \
3167       (builtin_types[(int) RETURN],                                      \
3168        tree_cons (NULL_TREE,                                             \
3169                   builtin_types[(int) ARG1],                             \
3170                   tree_cons (NULL_TREE,                                  \
3171                              builtin_types[(int) ARG2],                  \
3172                              tree_cons (NULL_TREE,                       \
3173                                         builtin_types[(int) ARG3],       \
3174                                         void_list_node))));
3175 #define DEF_FUNCTION_TYPE_4(ENUM, RETURN, ARG1, ARG2, ARG3, ARG4)       \
3176   builtin_types[(int) ENUM]                                             \
3177     = build_function_type                                               \
3178       (builtin_types[(int) RETURN],                                     \
3179        tree_cons (NULL_TREE,                                            \
3180                   builtin_types[(int) ARG1],                            \
3181                   tree_cons (NULL_TREE,                                 \
3182                              builtin_types[(int) ARG2],                 \
3183                              tree_cons                                  \
3184                              (NULL_TREE,                                \
3185                               builtin_types[(int) ARG3],                \
3186                               tree_cons (NULL_TREE,                     \
3187                                          builtin_types[(int) ARG4],     \
3188                                          void_list_node)))));
3189 #define DEF_FUNCTION_TYPE_VAR_0(ENUM, RETURN)                           \
3190   builtin_types[(int) ENUM]                                             \
3191     = build_function_type (builtin_types[(int) RETURN], NULL_TREE);
3192 #define DEF_FUNCTION_TYPE_VAR_1(ENUM, RETURN, ARG1)                      \
3193    builtin_types[(int) ENUM]                                             \
3194     = build_function_type (builtin_types[(int) RETURN],          \
3195                            tree_cons (NULL_TREE,                         \
3196                                       builtin_types[(int) ARG1],         \
3197                                       NULL_TREE));
3198
3199 #define DEF_FUNCTION_TYPE_VAR_2(ENUM, RETURN, ARG1, ARG2)       \
3200    builtin_types[(int) ENUM]                                    \
3201     = build_function_type                                       \
3202       (builtin_types[(int) RETURN],                             \
3203        tree_cons (NULL_TREE,                                    \
3204                   builtin_types[(int) ARG1],                    \
3205                   tree_cons (NULL_TREE,                         \
3206                              builtin_types[(int) ARG2],         \
3207                              NULL_TREE)));
3208
3209 #define DEF_FUNCTION_TYPE_VAR_3(ENUM, RETURN, ARG1, ARG2, ARG3)         \
3210    builtin_types[(int) ENUM]                                            \
3211     = build_function_type                                               \
3212       (builtin_types[(int) RETURN],                                     \
3213        tree_cons (NULL_TREE,                                            \
3214                   builtin_types[(int) ARG1],                            \
3215                   tree_cons (NULL_TREE,                                 \
3216                              builtin_types[(int) ARG2],                 \
3217                              tree_cons (NULL_TREE,                      \
3218                                         builtin_types[(int) ARG3],      \
3219                                         NULL_TREE))));
3220
3221 #define DEF_POINTER_TYPE(ENUM, TYPE)                    \
3222   builtin_types[(int) ENUM]                             \
3223     = build_pointer_type (builtin_types[(int) TYPE]);
3224 #include "builtin-types.def"
3225 #undef DEF_PRIMITIVE_TYPE
3226 #undef DEF_FUNCTION_TYPE_1
3227 #undef DEF_FUNCTION_TYPE_2
3228 #undef DEF_FUNCTION_TYPE_3
3229 #undef DEF_FUNCTION_TYPE_4
3230 #undef DEF_FUNCTION_TYPE_VAR_0
3231 #undef DEF_FUNCTION_TYPE_VAR_1
3232 #undef DEF_FUNCTION_TYPE_VAR_2
3233 #undef DEF_FUNCTION_TYPE_VAR_3
3234 #undef DEF_POINTER_TYPE
3235
3236   c_init_attributes ();
3237
3238 #define DEF_BUILTIN(ENUM, NAME, CLASS, TYPE, LIBTYPE, BOTH_P, FALLBACK_P, \
3239                     NONANSI_P, ATTRS, IMPLICIT, COND)                   \
3240   if (NAME && COND)                                                     \
3241     {                                                                   \
3242       tree decl;                                                        \
3243                                                                         \
3244       gcc_assert (!strncmp (NAME, "__builtin_",                         \
3245                             strlen ("__builtin_")));                    \
3246                                                                         \
3247       if (!BOTH_P)                                                      \
3248         decl = lang_hooks.builtin_function (NAME, builtin_types[TYPE],  \
3249                                  ENUM,                                  \
3250                                  CLASS,                                 \
3251                                  (FALLBACK_P                            \
3252                                   ? (NAME + strlen ("__builtin_"))      \
3253                                   : NULL),                              \
3254                                  built_in_attributes[(int) ATTRS]);     \
3255       else                                                              \
3256         decl = builtin_function_2 (NAME,                                \
3257                                    NAME + strlen ("__builtin_"),        \
3258                                    builtin_types[TYPE],                 \
3259                                    builtin_types[LIBTYPE],              \
3260                                    ENUM,                                \
3261                                    CLASS,                               \
3262                                    FALLBACK_P,                          \
3263                                    NONANSI_P,                           \
3264                                    built_in_attributes[(int) ATTRS]);   \
3265                                                                         \
3266       built_in_decls[(int) ENUM] = decl;                                \
3267       if (IMPLICIT)                                                     \
3268         implicit_built_in_decls[(int) ENUM] = decl;                     \
3269     }
3270 #include "builtins.def"
3271 #undef DEF_BUILTIN
3272
3273   build_common_builtin_nodes ();
3274
3275   targetm.init_builtins ();
3276   if (flag_mudflap)
3277     mudflap_init ();
3278
3279   main_identifier_node = get_identifier ("main");
3280 }
3281
3282 /* Look up the function in built_in_decls that corresponds to DECL
3283    and set ASMSPEC as its user assembler name.  DECL must be a
3284    function decl that declares a builtin.  */
3285
3286 void
3287 set_builtin_user_assembler_name (tree decl, const char *asmspec)
3288 {
3289   tree builtin;
3290   gcc_assert (TREE_CODE (decl) == FUNCTION_DECL
3291               && DECL_BUILT_IN_CLASS (decl) == BUILT_IN_NORMAL
3292               && asmspec != 0);
3293
3294   builtin = built_in_decls [DECL_FUNCTION_CODE (decl)];
3295   set_user_assembler_name (builtin, asmspec);
3296   if (DECL_FUNCTION_CODE (decl) == BUILT_IN_MEMCPY)
3297     init_block_move_fn (asmspec);
3298   else if (DECL_FUNCTION_CODE (decl) == BUILT_IN_MEMSET)
3299     init_block_clear_fn (asmspec);
3300 }
3301
3302 tree
3303 build_va_arg (tree expr, tree type)
3304 {
3305   return build1 (VA_ARG_EXPR, type, expr);
3306 }
3307
3308
3309 /* Linked list of disabled built-in functions.  */
3310
3311 typedef struct disabled_builtin
3312 {
3313   const char *name;
3314   struct disabled_builtin *next;
3315 } disabled_builtin;
3316 static disabled_builtin *disabled_builtins = NULL;
3317
3318 static bool builtin_function_disabled_p (const char *);
3319
3320 /* Disable a built-in function specified by -fno-builtin-NAME.  If NAME
3321    begins with "__builtin_", give an error.  */
3322
3323 void
3324 disable_builtin_function (const char *name)
3325 {
3326   if (strncmp (name, "__builtin_", strlen ("__builtin_")) == 0)
3327     error ("cannot disable built-in function %qs", name);
3328   else
3329     {
3330       disabled_builtin *new_disabled_builtin = XNEW (disabled_builtin);
3331       new_disabled_builtin->name = name;
3332       new_disabled_builtin->next = disabled_builtins;
3333       disabled_builtins = new_disabled_builtin;
3334     }
3335 }
3336
3337
3338 /* Return true if the built-in function NAME has been disabled, false
3339    otherwise.  */
3340
3341 static bool
3342 builtin_function_disabled_p (const char *name)
3343 {
3344   disabled_builtin *p;
3345   for (p = disabled_builtins; p != NULL; p = p->next)
3346     {
3347       if (strcmp (name, p->name) == 0)
3348         return true;
3349     }
3350   return false;
3351 }
3352
3353
3354 /* Possibly define a builtin function with one or two names.  BUILTIN_NAME
3355    is an __builtin_-prefixed name; NAME is the ordinary name; one or both
3356    of these may be NULL (though both being NULL is useless).
3357    BUILTIN_TYPE is the type of the __builtin_-prefixed function;
3358    TYPE is the type of the function with the ordinary name.  These
3359    may differ if the ordinary name is declared with a looser type to avoid
3360    conflicts with headers.  FUNCTION_CODE and CL are as for
3361    builtin_function.  If LIBRARY_NAME_P is nonzero, NAME is passed as
3362    the LIBRARY_NAME parameter to builtin_function when declaring BUILTIN_NAME.
3363    If NONANSI_P is true, the name NAME is treated as a non-ANSI name;
3364    ATTRS is the tree list representing the builtin's function attributes.
3365    Returns the declaration of BUILTIN_NAME, if any, otherwise
3366    the declaration of NAME.  Does not declare NAME if flag_no_builtin,
3367    or if NONANSI_P and flag_no_nonansi_builtin.  */
3368
3369 static tree
3370 builtin_function_2 (const char *builtin_name, const char *name,
3371                     tree builtin_type, tree type,
3372                     enum built_in_function function_code,
3373                     enum built_in_class cl, int library_name_p,
3374                     bool nonansi_p, tree attrs)
3375 {
3376   tree bdecl = NULL_TREE;
3377   tree decl = NULL_TREE;
3378
3379   if (builtin_name != 0)
3380     bdecl = lang_hooks.builtin_function (builtin_name, builtin_type,
3381                                          function_code, cl,
3382                                          library_name_p ? name : NULL, attrs);
3383
3384   if (name != 0 && !flag_no_builtin && !builtin_function_disabled_p (name)
3385       && !(nonansi_p && flag_no_nonansi_builtin))
3386     decl = lang_hooks.builtin_function (name, type, function_code, cl,
3387                                         NULL, attrs);
3388
3389   return (bdecl != 0 ? bdecl : decl);
3390 }
3391 \f
3392 /* Nonzero if the type T promotes to int.  This is (nearly) the
3393    integral promotions defined in ISO C99 6.3.1.1/2.  */
3394
3395 bool
3396 c_promoting_integer_type_p (tree t)
3397 {
3398   switch (TREE_CODE (t))
3399     {
3400     case INTEGER_TYPE:
3401       return (TYPE_MAIN_VARIANT (t) == char_type_node
3402               || TYPE_MAIN_VARIANT (t) == signed_char_type_node
3403               || TYPE_MAIN_VARIANT (t) == unsigned_char_type_node
3404               || TYPE_MAIN_VARIANT (t) == short_integer_type_node
3405               || TYPE_MAIN_VARIANT (t) == short_unsigned_type_node
3406               || TYPE_PRECISION (t) < TYPE_PRECISION (integer_type_node));
3407
3408     case ENUMERAL_TYPE:
3409       /* ??? Technically all enumerations not larger than an int
3410          promote to an int.  But this is used along code paths
3411          that only want to notice a size change.  */
3412       return TYPE_PRECISION (t) < TYPE_PRECISION (integer_type_node);
3413
3414     case BOOLEAN_TYPE:
3415       return 1;
3416
3417     default:
3418       return 0;
3419     }
3420 }
3421
3422 /* Return 1 if PARMS specifies a fixed number of parameters
3423    and none of their types is affected by default promotions.  */
3424
3425 int
3426 self_promoting_args_p (tree parms)
3427 {
3428   tree t;
3429   for (t = parms; t; t = TREE_CHAIN (t))
3430     {
3431       tree type = TREE_VALUE (t);
3432
3433       if (TREE_CHAIN (t) == 0 && type != void_type_node)
3434         return 0;
3435
3436       if (type == 0)
3437         return 0;
3438
3439       if (TYPE_MAIN_VARIANT (type) == float_type_node)
3440         return 0;
3441
3442       if (c_promoting_integer_type_p (type))
3443         return 0;
3444     }
3445   return 1;
3446 }
3447
3448 /* Recursively examines the array elements of TYPE, until a non-array
3449    element type is found.  */
3450
3451 tree
3452 strip_array_types (tree type)
3453 {
3454   while (TREE_CODE (type) == ARRAY_TYPE)
3455     type = TREE_TYPE (type);
3456
3457   return type;
3458 }
3459
3460 /* Recursively remove any '*' or '&' operator from TYPE.  */
3461 tree
3462 strip_pointer_operator (tree t)
3463 {
3464   while (POINTER_TYPE_P (t))
3465     t = TREE_TYPE (t);
3466   return t;
3467 }
3468
3469 /* Used to compare case labels.  K1 and K2 are actually tree nodes
3470    representing case labels, or NULL_TREE for a `default' label.
3471    Returns -1 if K1 is ordered before K2, -1 if K1 is ordered after
3472    K2, and 0 if K1 and K2 are equal.  */
3473
3474 int
3475 case_compare (splay_tree_key k1, splay_tree_key k2)
3476 {
3477   /* Consider a NULL key (such as arises with a `default' label) to be
3478      smaller than anything else.  */
3479   if (!k1)
3480     return k2 ? -1 : 0;
3481   else if (!k2)
3482     return k1 ? 1 : 0;
3483
3484   return tree_int_cst_compare ((tree) k1, (tree) k2);
3485 }
3486
3487 /* Process a case label for the range LOW_VALUE ... HIGH_VALUE.  If
3488    LOW_VALUE and HIGH_VALUE are both NULL_TREE then this case label is
3489    actually a `default' label.  If only HIGH_VALUE is NULL_TREE, then
3490    case label was declared using the usual C/C++ syntax, rather than
3491    the GNU case range extension.  CASES is a tree containing all the
3492    case ranges processed so far; COND is the condition for the
3493    switch-statement itself.  Returns the CASE_LABEL_EXPR created, or
3494    ERROR_MARK_NODE if no CASE_LABEL_EXPR is created.  */
3495
3496 tree
3497 c_add_case_label (splay_tree cases, tree cond, tree orig_type,
3498                   tree low_value, tree high_value)
3499 {
3500   tree type;
3501   tree label;
3502   tree case_label;
3503   splay_tree_node node;
3504
3505   /* Create the LABEL_DECL itself.  */
3506   label = create_artificial_label ();
3507
3508   /* If there was an error processing the switch condition, bail now
3509      before we get more confused.  */
3510   if (!cond || cond == error_mark_node)
3511     goto error_out;
3512
3513   if ((low_value && TREE_TYPE (low_value)
3514        && POINTER_TYPE_P (TREE_TYPE (low_value)))
3515       || (high_value && TREE_TYPE (high_value)
3516           && POINTER_TYPE_P (TREE_TYPE (high_value))))
3517     error ("pointers are not permitted as case values");
3518
3519   /* Case ranges are a GNU extension.  */
3520   if (high_value && pedantic)
3521     pedwarn ("range expressions in switch statements are non-standard");
3522
3523   type = TREE_TYPE (cond);
3524   if (low_value)
3525     {
3526       low_value = check_case_value (low_value);
3527       low_value = convert_and_check (type, low_value);
3528     }
3529   if (high_value)
3530     {
3531       high_value = check_case_value (high_value);
3532       high_value = convert_and_check (type, high_value);
3533     }
3534
3535   /* If an error has occurred, bail out now.  */
3536   if (low_value == error_mark_node || high_value == error_mark_node)
3537     goto error_out;
3538
3539   /* If the LOW_VALUE and HIGH_VALUE are the same, then this isn't
3540      really a case range, even though it was written that way.  Remove
3541      the HIGH_VALUE to simplify later processing.  */
3542   if (tree_int_cst_equal (low_value, high_value))
3543     high_value = NULL_TREE;
3544   if (low_value && high_value
3545       && !tree_int_cst_lt (low_value, high_value))
3546     warning ("empty range specified");
3547
3548   /* See if the case is in range of the type of the original testing
3549      expression.  If both low_value and high_value are out of range,
3550      don't insert the case label and return NULL_TREE.  */
3551   if (low_value
3552       && !check_case_bounds (type, orig_type,
3553                              &low_value, high_value ? &high_value : NULL))
3554     return NULL_TREE;
3555
3556   /* Look up the LOW_VALUE in the table of case labels we already
3557      have.  */
3558   node = splay_tree_lookup (cases, (splay_tree_key) low_value);
3559   /* If there was not an exact match, check for overlapping ranges.
3560      There's no need to do this if there's no LOW_VALUE or HIGH_VALUE;
3561      that's a `default' label and the only overlap is an exact match.  */
3562   if (!node && (low_value || high_value))
3563     {
3564       splay_tree_node low_bound;
3565       splay_tree_node high_bound;
3566
3567       /* Even though there wasn't an exact match, there might be an
3568          overlap between this case range and another case range.
3569          Since we've (inductively) not allowed any overlapping case
3570          ranges, we simply need to find the greatest low case label
3571          that is smaller that LOW_VALUE, and the smallest low case
3572          label that is greater than LOW_VALUE.  If there is an overlap
3573          it will occur in one of these two ranges.  */
3574       low_bound = splay_tree_predecessor (cases,
3575                                           (splay_tree_key) low_value);
3576       high_bound = splay_tree_successor (cases,
3577                                          (splay_tree_key) low_value);
3578
3579       /* Check to see if the LOW_BOUND overlaps.  It is smaller than
3580          the LOW_VALUE, so there is no need to check unless the
3581          LOW_BOUND is in fact itself a case range.  */
3582       if (low_bound
3583           && CASE_HIGH ((tree) low_bound->value)
3584           && tree_int_cst_compare (CASE_HIGH ((tree) low_bound->value),
3585                                     low_value) >= 0)
3586         node = low_bound;
3587       /* Check to see if the HIGH_BOUND overlaps.  The low end of that
3588          range is bigger than the low end of the current range, so we
3589          are only interested if the current range is a real range, and
3590          not an ordinary case label.  */
3591       else if (high_bound
3592                && high_value
3593                && (tree_int_cst_compare ((tree) high_bound->key,
3594                                          high_value)
3595                    <= 0))
3596         node = high_bound;
3597     }
3598   /* If there was an overlap, issue an error.  */
3599   if (node)
3600     {
3601       tree duplicate = CASE_LABEL ((tree) node->value);
3602
3603       if (high_value)
3604         {
3605           error ("duplicate (or overlapping) case value");
3606           error ("%Jthis is the first entry overlapping that value", duplicate);
3607         }
3608       else if (low_value)
3609         {
3610           error ("duplicate case value") ;
3611           error ("%Jpreviously used here", duplicate);
3612         }
3613       else
3614         {
3615           error ("multiple default labels in one switch");
3616           error ("%Jthis is the first default label", duplicate);
3617         }
3618       goto error_out;
3619     }
3620
3621   /* Add a CASE_LABEL to the statement-tree.  */
3622   case_label = add_stmt (build_case_label (low_value, high_value, label));
3623   /* Register this case label in the splay tree.  */
3624   splay_tree_insert (cases,
3625                      (splay_tree_key) low_value,
3626                      (splay_tree_value) case_label);
3627
3628   return case_label;
3629
3630  error_out:
3631   /* Add a label so that the back-end doesn't think that the beginning of
3632      the switch is unreachable.  Note that we do not add a case label, as
3633      that just leads to duplicates and thence to aborts later on.  */
3634   if (!cases->root)
3635     {
3636       tree t = create_artificial_label ();
3637       add_stmt (build_stmt (LABEL_EXPR, t));
3638     }
3639   return error_mark_node;
3640 }
3641
3642 /* Subroutines of c_do_switch_warnings, called via splay_tree_foreach.
3643    Used to verify that case values match up with enumerator values.  */
3644
3645 static void
3646 match_case_to_enum_1 (tree key, tree type, tree label)
3647 {
3648   char buf[2 + 2*HOST_BITS_PER_WIDE_INT/4 + 1];
3649
3650   /* ??? Not working too hard to print the double-word value.
3651      Should perhaps be done with %lwd in the diagnostic routines?  */
3652   if (TREE_INT_CST_HIGH (key) == 0)
3653     snprintf (buf, sizeof (buf), HOST_WIDE_INT_PRINT_UNSIGNED,
3654               TREE_INT_CST_LOW (key));
3655   else if (!TYPE_UNSIGNED (type)
3656            && TREE_INT_CST_HIGH (key) == -1
3657            && TREE_INT_CST_LOW (key) != 0)
3658     snprintf (buf, sizeof (buf), "-" HOST_WIDE_INT_PRINT_UNSIGNED,
3659               -TREE_INT_CST_LOW (key));
3660   else
3661     snprintf (buf, sizeof (buf), HOST_WIDE_INT_PRINT_DOUBLE_HEX,
3662               TREE_INT_CST_HIGH (key), TREE_INT_CST_LOW (key));
3663
3664   if (TYPE_NAME (type) == 0)
3665     warning ("%Jcase value %qs not in enumerated type",
3666              CASE_LABEL (label), buf);
3667   else
3668     warning ("%Jcase value %qs not in enumerated type %qT",
3669              CASE_LABEL (label), buf, type);
3670 }
3671
3672 static int
3673 match_case_to_enum (splay_tree_node node, void *data)
3674 {
3675   tree label = (tree) node->value;
3676   tree type = (tree) data;
3677
3678   /* Skip default case.  */
3679   if (!CASE_LOW (label))
3680     return 0;
3681
3682   /* If TREE_ADDRESSABLE is not set, that means CASE_LOW did not appear
3683      when we did our enum->case scan.  Reset our scratch bit after.  */
3684   if (!TREE_ADDRESSABLE (label))
3685     match_case_to_enum_1 (CASE_LOW (label), type, label);
3686   else
3687     TREE_ADDRESSABLE (label) = 0;
3688
3689   /* If CASE_HIGH is non-null, we have a range.  Here we must search.
3690      Note that the old code in stmt.c did not check for the values in
3691      the range either, just the endpoints.  */
3692   if (CASE_HIGH (label))
3693     {
3694       tree chain, key = CASE_HIGH (label);
3695
3696       for (chain = TYPE_VALUES (type);
3697            chain && !tree_int_cst_equal (key, TREE_VALUE (chain));
3698            chain = TREE_CHAIN (chain))
3699         continue;
3700       if (!chain)
3701         match_case_to_enum_1 (key, type, label);
3702     }
3703
3704   return 0;
3705 }
3706
3707 /* Handle -Wswitch*.  Called from the front end after parsing the switch
3708    construct.  */
3709 /* ??? Should probably be somewhere generic, since other languages besides
3710    C and C++ would want this.  We'd want to agree on the data structure,
3711    however, which is a problem.  Alternately, we operate on gimplified
3712    switch_exprs, which I don't especially like.  At the moment, however,
3713    C/C++ are the only tree-ssa languages that support enumerations at all,
3714    so the point is moot.  */
3715
3716 void
3717 c_do_switch_warnings (splay_tree cases, tree switch_stmt)
3718 {
3719   splay_tree_node default_node;
3720   location_t switch_location;
3721   tree type;
3722
3723   if (!warn_switch && !warn_switch_enum && !warn_switch_default)
3724     return;
3725
3726   if (EXPR_HAS_LOCATION (switch_stmt))
3727     switch_location = EXPR_LOCATION (switch_stmt);
3728   else
3729     switch_location = input_location;
3730
3731   type = SWITCH_STMT_TYPE (switch_stmt);
3732
3733   default_node = splay_tree_lookup (cases, (splay_tree_key) NULL);
3734   if (warn_switch_default && !default_node)
3735     warning ("%Hswitch missing default case", &switch_location);
3736
3737   /* If the switch expression was an enumerated type, check that
3738      exactly all enumeration literals are covered by the cases.
3739      The check is made when -Wswitch was specified and there is no
3740      default case, or when -Wswitch-enum was specified.  */
3741   if (((warn_switch && !default_node) || warn_switch_enum)
3742       && type && TREE_CODE (type) == ENUMERAL_TYPE
3743       && TREE_CODE (SWITCH_STMT_COND (switch_stmt)) != INTEGER_CST)
3744     {
3745       tree chain;
3746
3747       /* The time complexity here is O(N*lg(N)) worst case, but for the
3748          common case of monotonically increasing enumerators, it is
3749          O(N), since the nature of the splay tree will keep the next
3750          element adjacent to the root at all times.  */
3751
3752       for (chain = TYPE_VALUES (type); chain; chain = TREE_CHAIN (chain))
3753         {
3754           splay_tree_node node
3755             = splay_tree_lookup (cases, (splay_tree_key) TREE_VALUE (chain));
3756
3757           if (node)
3758             {
3759               /* Mark the CASE_LOW part of the case entry as seen, so
3760                  that we save time later.  Choose TREE_ADDRESSABLE
3761                  randomly as a bit that won't have been set to-date.  */
3762               tree label = (tree) node->value;
3763               TREE_ADDRESSABLE (label) = 1;
3764             }
3765           else
3766             {
3767               /* Warn if there are enumerators that don't correspond to
3768                  case expressions.  */
3769               warning ("%Henumeration value %qE not handled in switch",
3770                        &switch_location, TREE_PURPOSE (chain));
3771             }
3772         }
3773
3774       /* Warn if there are case expressions that don't correspond to
3775          enumerators.  This can occur since C and C++ don't enforce
3776          type-checking of assignments to enumeration variables.
3777
3778          The time complexity here is O(N**2) worst case, since we've
3779          not sorted the enumeration values.  However, in the absence
3780          of case ranges this is O(N), since all single cases that
3781          corresponded to enumerations have been marked above.  */
3782
3783       splay_tree_foreach (cases, match_case_to_enum, type);
3784     }
3785 }
3786
3787 /* Finish an expression taking the address of LABEL (an
3788    IDENTIFIER_NODE).  Returns an expression for the address.  */
3789
3790 tree
3791 finish_label_address_expr (tree label)
3792 {
3793   tree result;
3794
3795   if (pedantic)
3796     pedwarn ("taking the address of a label is non-standard");
3797
3798   if (label == error_mark_node)
3799     return error_mark_node;
3800
3801   label = lookup_label (label);
3802   if (label == NULL_TREE)
3803     result = null_pointer_node;
3804   else
3805     {
3806       TREE_USED (label) = 1;
3807       result = build1 (ADDR_EXPR, ptr_type_node, label);
3808       /* The current function in not necessarily uninlinable.
3809          Computed gotos are incompatible with inlining, but the value
3810          here could be used only in a diagnostic, for example.  */
3811     }
3812
3813   return result;
3814 }
3815
3816 /* Hook used by expand_expr to expand language-specific tree codes.  */
3817 /* The only things that should go here are bits needed to expand
3818    constant initializers.  Everything else should be handled by the
3819    gimplification routines.  */
3820
3821 rtx
3822 c_expand_expr (tree exp, rtx target, enum machine_mode tmode,
3823                int modifier /* Actually enum_modifier.  */,
3824                rtx *alt_rtl)
3825 {
3826   switch (TREE_CODE (exp))
3827     {
3828     case COMPOUND_LITERAL_EXPR:
3829       {
3830         /* Initialize the anonymous variable declared in the compound
3831            literal, then return the variable.  */
3832         tree decl = COMPOUND_LITERAL_EXPR_DECL (exp);
3833         emit_local_var (decl);
3834         return expand_expr_real (decl, target, tmode, modifier, alt_rtl);
3835       }
3836
3837     default:
3838       gcc_unreachable ();
3839     }
3840 }
3841
3842 /* Hook used by staticp to handle language-specific tree codes.  */
3843
3844 tree
3845 c_staticp (tree exp)
3846 {
3847   return (TREE_CODE (exp) == COMPOUND_LITERAL_EXPR
3848           && TREE_STATIC (COMPOUND_LITERAL_EXPR_DECL (exp))
3849           ? exp : NULL);
3850 }
3851 \f
3852
3853 /* Given a boolean expression ARG, return a tree representing an increment
3854    or decrement (as indicated by CODE) of ARG.  The front end must check for
3855    invalid cases (e.g., decrement in C++).  */
3856 tree
3857 boolean_increment (enum tree_code code, tree arg)
3858 {
3859   tree val;
3860   tree true_res = boolean_true_node;
3861
3862   arg = stabilize_reference (arg);
3863   switch (code)
3864     {
3865     case PREINCREMENT_EXPR:
3866       val = build2 (MODIFY_EXPR, TREE_TYPE (arg), arg, true_res);
3867       break;
3868     case POSTINCREMENT_EXPR:
3869       val = build2 (MODIFY_EXPR, TREE_TYPE (arg), arg, true_res);
3870       arg = save_expr (arg);
3871       val = build2 (COMPOUND_EXPR, TREE_TYPE (arg), val, arg);
3872       val = build2 (COMPOUND_EXPR, TREE_TYPE (arg), arg, val);
3873       break;
3874     case PREDECREMENT_EXPR:
3875       val = build2 (MODIFY_EXPR, TREE_TYPE (arg), arg,
3876                     invert_truthvalue (arg));
3877       break;
3878     case POSTDECREMENT_EXPR:
3879       val = build2 (MODIFY_EXPR, TREE_TYPE (arg), arg,
3880                     invert_truthvalue (arg));
3881       arg = save_expr (arg);
3882       val = build2 (COMPOUND_EXPR, TREE_TYPE (arg), val, arg);
3883       val = build2 (COMPOUND_EXPR, TREE_TYPE (arg), arg, val);
3884       break;
3885     default:
3886       gcc_unreachable ();
3887     }
3888   TREE_SIDE_EFFECTS (val) = 1;
3889   return val;
3890 }
3891 \f
3892 /* Built-in macros for stddef.h, that require macros defined in this
3893    file.  */
3894 void
3895 c_stddef_cpp_builtins(void)
3896 {
3897   builtin_define_with_value ("__SIZE_TYPE__", SIZE_TYPE, 0);
3898   builtin_define_with_value ("__PTRDIFF_TYPE__", PTRDIFF_TYPE, 0);
3899   builtin_define_with_value ("__WCHAR_TYPE__", MODIFIED_WCHAR_TYPE, 0);
3900   builtin_define_with_value ("__WINT_TYPE__", WINT_TYPE, 0);
3901   builtin_define_with_value ("__INTMAX_TYPE__", INTMAX_TYPE, 0);
3902   builtin_define_with_value ("__UINTMAX_TYPE__", UINTMAX_TYPE, 0);
3903 }
3904
3905 static void
3906 c_init_attributes (void)
3907 {
3908   /* Fill in the built_in_attributes array.  */
3909 #define DEF_ATTR_NULL_TREE(ENUM)                                \
3910   built_in_attributes[(int) ENUM] = NULL_TREE;
3911 #define DEF_ATTR_INT(ENUM, VALUE)                               \
3912   built_in_attributes[(int) ENUM] = build_int_cst (NULL_TREE, VALUE);
3913 #define DEF_ATTR_IDENT(ENUM, STRING)                            \
3914   built_in_attributes[(int) ENUM] = get_identifier (STRING);
3915 #define DEF_ATTR_TREE_LIST(ENUM, PURPOSE, VALUE, CHAIN) \
3916   built_in_attributes[(int) ENUM]                       \
3917     = tree_cons (built_in_attributes[(int) PURPOSE],    \
3918                  built_in_attributes[(int) VALUE],      \
3919                  built_in_attributes[(int) CHAIN]);
3920 #include "builtin-attrs.def"
3921 #undef DEF_ATTR_NULL_TREE
3922 #undef DEF_ATTR_INT
3923 #undef DEF_ATTR_IDENT
3924 #undef DEF_ATTR_TREE_LIST
3925 }
3926
3927 /* Attribute handlers common to C front ends.  */
3928
3929 /* Handle a "packed" attribute; arguments as in
3930    struct attribute_spec.handler.  */
3931
3932 static tree
3933 handle_packed_attribute (tree *node, tree name, tree ARG_UNUSED (args),
3934                          int flags, bool *no_add_attrs)
3935 {
3936   if (TYPE_P (*node))
3937     {
3938       if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
3939         *node = build_variant_type_copy (*node);
3940       TYPE_PACKED (*node) = 1;
3941       if (TYPE_MAIN_VARIANT (*node) == *node)
3942         {
3943           /* If it is the main variant, then pack the other variants
3944              too. This happens in,
3945
3946              struct Foo {
3947                struct Foo const *ptr; // creates a variant w/o packed flag
3948                } __ attribute__((packed)); // packs it now.
3949           */
3950           tree probe;
3951
3952           for (probe = *node; probe; probe = TYPE_NEXT_VARIANT (probe))
3953             TYPE_PACKED (probe) = 1;
3954         }
3955
3956     }
3957   else if (TREE_CODE (*node) == FIELD_DECL)
3958     DECL_PACKED (*node) = 1;
3959   /* We can't set DECL_PACKED for a VAR_DECL, because the bit is
3960      used for DECL_REGISTER.  It wouldn't mean anything anyway.
3961      We can't set DECL_PACKED on the type of a TYPE_DECL, because
3962      that changes what the typedef is typing.  */
3963   else
3964     {
3965       warning ("%qE attribute ignored", name);
3966       *no_add_attrs = true;
3967     }
3968
3969   return NULL_TREE;
3970 }
3971
3972 /* Handle a "nocommon" attribute; arguments as in
3973    struct attribute_spec.handler.  */
3974
3975 static tree
3976 handle_nocommon_attribute (tree *node, tree name,
3977                            tree ARG_UNUSED (args),
3978                            int ARG_UNUSED (flags), bool *no_add_attrs)
3979 {
3980   if (TREE_CODE (*node) == VAR_DECL)
3981     DECL_COMMON (*node) = 0;
3982   else
3983     {
3984       warning ("%qE attribute ignored", name);
3985       *no_add_attrs = true;
3986     }
3987
3988   return NULL_TREE;
3989 }
3990
3991 /* Handle a "common" attribute; arguments as in
3992    struct attribute_spec.handler.  */
3993
3994 static tree
3995 handle_common_attribute (tree *node, tree name, tree ARG_UNUSED (args),
3996                          int ARG_UNUSED (flags), bool *no_add_attrs)
3997 {
3998   if (TREE_CODE (*node) == VAR_DECL)
3999     DECL_COMMON (*node) = 1;
4000   else
4001     {
4002       warning ("%qE attribute ignored", name);
4003       *no_add_attrs = true;
4004     }
4005
4006   return NULL_TREE;
4007 }
4008
4009 /* Handle a "noreturn" attribute; arguments as in
4010    struct attribute_spec.handler.  */
4011
4012 static tree
4013 handle_noreturn_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4014                            int ARG_UNUSED (flags), bool *no_add_attrs)
4015 {
4016   tree type = TREE_TYPE (*node);
4017
4018   /* See FIXME comment in c_common_attribute_table.  */
4019   if (TREE_CODE (*node) == FUNCTION_DECL)
4020     TREE_THIS_VOLATILE (*node) = 1;
4021   else if (TREE_CODE (type) == POINTER_TYPE
4022            && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE)
4023     TREE_TYPE (*node)
4024       = build_pointer_type
4025         (build_type_variant (TREE_TYPE (type),
4026                              TYPE_READONLY (TREE_TYPE (type)), 1));
4027   else
4028     {
4029       warning ("%qE attribute ignored", name);
4030       *no_add_attrs = true;
4031     }
4032
4033   return NULL_TREE;
4034 }
4035
4036 /* Handle a "noinline" attribute; arguments as in
4037    struct attribute_spec.handler.  */
4038
4039 static tree
4040 handle_noinline_attribute (tree *node, tree name,
4041                            tree ARG_UNUSED (args),
4042                            int ARG_UNUSED (flags), bool *no_add_attrs)
4043 {
4044   if (TREE_CODE (*node) == FUNCTION_DECL)
4045     DECL_UNINLINABLE (*node) = 1;
4046   else
4047     {
4048       warning ("%qE attribute ignored", name);
4049       *no_add_attrs = true;
4050     }
4051
4052   return NULL_TREE;
4053 }
4054
4055 /* Handle a "always_inline" attribute; arguments as in
4056    struct attribute_spec.handler.  */
4057
4058 static tree
4059 handle_always_inline_attribute (tree *node, tree name,
4060                                 tree ARG_UNUSED (args),
4061                                 int ARG_UNUSED (flags),
4062                                 bool *no_add_attrs)
4063 {
4064   if (TREE_CODE (*node) == FUNCTION_DECL)
4065     {
4066       /* Do nothing else, just set the attribute.  We'll get at
4067          it later with lookup_attribute.  */
4068     }
4069   else
4070     {
4071       warning ("%qE attribute ignored", name);
4072       *no_add_attrs = true;
4073     }
4074
4075   return NULL_TREE;
4076 }
4077
4078 /* Handle a "used" attribute; arguments as in
4079    struct attribute_spec.handler.  */
4080
4081 static tree
4082 handle_used_attribute (tree *pnode, tree name, tree ARG_UNUSED (args),
4083                        int ARG_UNUSED (flags), bool *no_add_attrs)
4084 {
4085   tree node = *pnode;
4086
4087   if (TREE_CODE (node) == FUNCTION_DECL
4088       || (TREE_CODE (node) == VAR_DECL && TREE_STATIC (node)))
4089     {
4090       TREE_USED (node) = 1;
4091       DECL_PRESERVE_P (node) = 1;
4092     }
4093   else
4094     {
4095       warning ("%qE attribute ignored", name);
4096       *no_add_attrs = true;
4097     }
4098
4099   return NULL_TREE;
4100 }
4101
4102 /* Handle a "unused" attribute; arguments as in
4103    struct attribute_spec.handler.  */
4104
4105 static tree
4106 handle_unused_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4107                          int flags, bool *no_add_attrs)
4108 {
4109   if (DECL_P (*node))
4110     {
4111       tree decl = *node;
4112
4113       if (TREE_CODE (decl) == PARM_DECL
4114           || TREE_CODE (decl) == VAR_DECL
4115           || TREE_CODE (decl) == FUNCTION_DECL
4116           || TREE_CODE (decl) == LABEL_DECL
4117           || TREE_CODE (decl) == TYPE_DECL)
4118         TREE_USED (decl) = 1;
4119       else
4120         {
4121           warning ("%qE attribute ignored", name);
4122           *no_add_attrs = true;
4123         }
4124     }
4125   else
4126     {
4127       if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
4128         *node = build_variant_type_copy (*node);
4129       TREE_USED (*node) = 1;
4130     }
4131
4132   return NULL_TREE;
4133 }
4134
4135 /* Handle a "const" attribute; arguments as in
4136    struct attribute_spec.handler.  */
4137
4138 static tree
4139 handle_const_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4140                         int ARG_UNUSED (flags), bool *no_add_attrs)
4141 {
4142   tree type = TREE_TYPE (*node);
4143
4144   /* See FIXME comment on noreturn in c_common_attribute_table.  */
4145   if (TREE_CODE (*node) == FUNCTION_DECL)
4146     TREE_READONLY (*node) = 1;
4147   else if (TREE_CODE (type) == POINTER_TYPE
4148            && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE)
4149     TREE_TYPE (*node)
4150       = build_pointer_type
4151         (build_type_variant (TREE_TYPE (type), 1,
4152                              TREE_THIS_VOLATILE (TREE_TYPE (type))));
4153   else
4154     {
4155       warning ("%qE attribute ignored", name);
4156       *no_add_attrs = true;
4157     }
4158
4159   return NULL_TREE;
4160 }
4161
4162 /* Handle a "transparent_union" attribute; arguments as in
4163    struct attribute_spec.handler.  */
4164
4165 static tree
4166 handle_transparent_union_attribute (tree *node, tree name,
4167                                     tree ARG_UNUSED (args), int flags,
4168                                     bool *no_add_attrs)
4169 {
4170   tree decl = NULL_TREE;
4171   tree *type = NULL;
4172   int is_type = 0;
4173
4174   if (DECL_P (*node))
4175     {
4176       decl = *node;
4177       type = &TREE_TYPE (decl);
4178       is_type = TREE_CODE (*node) == TYPE_DECL;
4179     }
4180   else if (TYPE_P (*node))
4181     type = node, is_type = 1;
4182
4183   if (is_type
4184       && TREE_CODE (*type) == UNION_TYPE
4185       && (decl == 0
4186           || (TYPE_FIELDS (*type) != 0
4187               && TYPE_MODE (*type) == DECL_MODE (TYPE_FIELDS (*type)))))
4188     {
4189       if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
4190         *type = build_variant_type_copy (*type);
4191       TYPE_TRANSPARENT_UNION (*type) = 1;
4192     }
4193   else if (decl != 0 && TREE_CODE (decl) == PARM_DECL
4194            && TREE_CODE (*type) == UNION_TYPE
4195            && TYPE_MODE (*type) == DECL_MODE (TYPE_FIELDS (*type)))
4196     DECL_TRANSPARENT_UNION (decl) = 1;
4197   else
4198     {
4199       warning ("%qE attribute ignored", name);
4200       *no_add_attrs = true;
4201     }
4202
4203   return NULL_TREE;
4204 }
4205
4206 /* Handle a "constructor" attribute; arguments as in
4207    struct attribute_spec.handler.  */
4208
4209 static tree
4210 handle_constructor_attribute (tree *node, tree name,
4211                               tree ARG_UNUSED (args),
4212                               int ARG_UNUSED (flags),
4213                               bool *no_add_attrs)
4214 {
4215   tree decl = *node;
4216   tree type = TREE_TYPE (decl);
4217
4218   if (TREE_CODE (decl) == FUNCTION_DECL
4219       && TREE_CODE (type) == FUNCTION_TYPE
4220       && decl_function_context (decl) == 0)
4221     {
4222       DECL_STATIC_CONSTRUCTOR (decl) = 1;
4223       TREE_USED (decl) = 1;
4224     }
4225   else
4226     {
4227       warning ("%qE attribute ignored", name);
4228       *no_add_attrs = true;
4229     }
4230
4231   return NULL_TREE;
4232 }
4233
4234 /* Handle a "destructor" attribute; arguments as in
4235    struct attribute_spec.handler.  */
4236
4237 static tree
4238 handle_destructor_attribute (tree *node, tree name,
4239                              tree ARG_UNUSED (args),
4240                              int ARG_UNUSED (flags),
4241                              bool *no_add_attrs)
4242 {
4243   tree decl = *node;
4244   tree type = TREE_TYPE (decl);
4245
4246   if (TREE_CODE (decl) == FUNCTION_DECL
4247       && TREE_CODE (type) == FUNCTION_TYPE
4248       && decl_function_context (decl) == 0)
4249     {
4250       DECL_STATIC_DESTRUCTOR (decl) = 1;
4251       TREE_USED (decl) = 1;
4252     }
4253   else
4254     {
4255       warning ("%qE attribute ignored", name);
4256       *no_add_attrs = true;
4257     }
4258
4259   return NULL_TREE;
4260 }
4261
4262 /* Handle a "mode" attribute; arguments as in
4263    struct attribute_spec.handler.  */
4264
4265 static tree
4266 handle_mode_attribute (tree *node, tree name, tree args,
4267                        int ARG_UNUSED (flags), bool *no_add_attrs)
4268 {
4269   tree type = *node;
4270
4271   *no_add_attrs = true;
4272
4273   if (TREE_CODE (TREE_VALUE (args)) != IDENTIFIER_NODE)
4274     warning ("%qE attribute ignored", name);
4275   else
4276     {
4277       int j;
4278       const char *p = IDENTIFIER_POINTER (TREE_VALUE (args));
4279       int len = strlen (p);
4280       enum machine_mode mode = VOIDmode;
4281       tree typefm;
4282       bool valid_mode;
4283
4284       if (len > 4 && p[0] == '_' && p[1] == '_'
4285           && p[len - 1] == '_' && p[len - 2] == '_')
4286         {
4287           char *newp = (char *) alloca (len - 1);
4288
4289           strcpy (newp, &p[2]);
4290           newp[len - 4] = '\0';
4291           p = newp;
4292         }
4293
4294       /* Change this type to have a type with the specified mode.
4295          First check for the special modes.  */
4296       if (!strcmp (p, "byte"))
4297         mode = byte_mode;
4298       else if (!strcmp (p, "word"))
4299         mode = word_mode;
4300       else if (!strcmp (p, "pointer"))
4301         mode = ptr_mode;
4302       else
4303         for (j = 0; j < NUM_MACHINE_MODES; j++)
4304           if (!strcmp (p, GET_MODE_NAME (j)))
4305             {
4306               mode = (enum machine_mode) j;
4307               break;
4308             }
4309
4310       if (mode == VOIDmode)
4311         {
4312           error ("unknown machine mode %qs", p);
4313           return NULL_TREE;
4314         }
4315
4316       valid_mode = false;
4317       switch (GET_MODE_CLASS (mode))
4318         {
4319         case MODE_INT:
4320         case MODE_PARTIAL_INT:
4321         case MODE_FLOAT:
4322           valid_mode = targetm.scalar_mode_supported_p (mode);
4323           break;
4324
4325         case MODE_COMPLEX_INT:
4326         case MODE_COMPLEX_FLOAT:
4327           valid_mode = targetm.scalar_mode_supported_p (GET_MODE_INNER (mode));
4328           break;
4329
4330         case MODE_VECTOR_INT:
4331         case MODE_VECTOR_FLOAT:
4332           warning ("specifying vector types with __attribute__ ((mode)) "
4333                    "is deprecated");
4334           warning ("use __attribute__ ((vector_size)) instead");
4335           valid_mode = vector_mode_valid_p (mode);
4336           break;
4337
4338         default:
4339           break;
4340         }
4341       if (!valid_mode)
4342         {
4343           error ("unable to emulate %qs", p);
4344           return NULL_TREE;
4345         }
4346
4347       if (POINTER_TYPE_P (type))
4348         {
4349           tree (*fn)(tree, enum machine_mode, bool);
4350
4351           if (!targetm.valid_pointer_mode (mode))
4352             {
4353               error ("invalid pointer mode %qs", p);
4354               return NULL_TREE;
4355             }
4356
4357           if (TREE_CODE (type) == POINTER_TYPE)
4358             fn = build_pointer_type_for_mode;
4359           else
4360             fn = build_reference_type_for_mode;
4361           typefm = fn (TREE_TYPE (type), mode, false);
4362         }
4363       else
4364         typefm = lang_hooks.types.type_for_mode (mode, TYPE_UNSIGNED (type));
4365
4366       if (typefm == NULL_TREE)
4367         {
4368           error ("no data type for mode %qs", p);
4369           return NULL_TREE;
4370         }
4371       else if (TREE_CODE (type) == ENUMERAL_TYPE)
4372         {
4373           /* For enumeral types, copy the precision from the integer
4374              type returned above.  If not an INTEGER_TYPE, we can't use
4375              this mode for this type.  */
4376           if (TREE_CODE (typefm) != INTEGER_TYPE)
4377             {
4378               error ("cannot use mode %qs for enumeral types", p);
4379               return NULL_TREE;
4380             }
4381
4382           if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
4383             type = build_variant_type_copy (type);
4384
4385           /* We cannot use layout_type here, because that will attempt
4386              to re-layout all variants, corrupting our original.  */
4387           TYPE_PRECISION (type) = TYPE_PRECISION (typefm);
4388           TYPE_MIN_VALUE (type) = TYPE_MIN_VALUE (typefm);
4389           TYPE_MAX_VALUE (type) = TYPE_MAX_VALUE (typefm);
4390           TYPE_SIZE (type) = TYPE_SIZE (typefm);
4391           TYPE_SIZE_UNIT (type) = TYPE_SIZE_UNIT (typefm);
4392           TYPE_MODE (type) = TYPE_MODE (typefm);
4393           if (!TYPE_USER_ALIGN (type))
4394             TYPE_ALIGN (type) = TYPE_ALIGN (typefm);
4395
4396           typefm = type;
4397         }
4398       else if (VECTOR_MODE_P (mode)
4399                ? TREE_CODE (type) != TREE_CODE (TREE_TYPE (typefm))
4400                : TREE_CODE (type) != TREE_CODE (typefm))
4401         {
4402           error ("mode %qs applied to inappropriate type", p);
4403           return NULL_TREE;
4404         }
4405
4406       *node = typefm;
4407     }
4408
4409   return NULL_TREE;
4410 }
4411
4412 /* Handle a "section" attribute; arguments as in
4413    struct attribute_spec.handler.  */
4414
4415 static tree
4416 handle_section_attribute (tree *node, tree ARG_UNUSED (name), tree args,
4417                           int ARG_UNUSED (flags), bool *no_add_attrs)
4418 {
4419   tree decl = *node;
4420
4421   if (targetm.have_named_sections)
4422     {
4423       user_defined_section_attribute = true;
4424
4425       if ((TREE_CODE (decl) == FUNCTION_DECL
4426            || TREE_CODE (decl) == VAR_DECL)
4427           && TREE_CODE (TREE_VALUE (args)) == STRING_CST)
4428         {
4429           if (TREE_CODE (decl) == VAR_DECL
4430               && current_function_decl != NULL_TREE
4431               && !TREE_STATIC (decl))
4432             {
4433               error ("%Jsection attribute cannot be specified for "
4434                      "local variables", decl);
4435               *no_add_attrs = true;
4436             }
4437
4438           /* The decl may have already been given a section attribute
4439              from a previous declaration.  Ensure they match.  */
4440           else if (DECL_SECTION_NAME (decl) != NULL_TREE
4441                    && strcmp (TREE_STRING_POINTER (DECL_SECTION_NAME (decl)),
4442                               TREE_STRING_POINTER (TREE_VALUE (args))) != 0)
4443             {
4444               error ("%Jsection of %qD conflicts with previous declaration",
4445                      *node, *node);
4446               *no_add_attrs = true;
4447             }
4448           else
4449             DECL_SECTION_NAME (decl) = TREE_VALUE (args);
4450         }
4451       else
4452         {
4453           error ("%Jsection attribute not allowed for %qD", *node, *node);
4454           *no_add_attrs = true;
4455         }
4456     }
4457   else
4458     {
4459       error ("%Jsection attributes are not supported for this target", *node);
4460       *no_add_attrs = true;
4461     }
4462
4463   return NULL_TREE;
4464 }
4465
4466 /* Handle a "aligned" attribute; arguments as in
4467    struct attribute_spec.handler.  */
4468
4469 static tree
4470 handle_aligned_attribute (tree *node, tree ARG_UNUSED (name), tree args,
4471                           int flags, bool *no_add_attrs)
4472 {
4473   tree decl = NULL_TREE;
4474   tree *type = NULL;
4475   int is_type = 0;
4476   tree align_expr = (args ? TREE_VALUE (args)
4477                      : size_int (BIGGEST_ALIGNMENT / BITS_PER_UNIT));
4478   int i;
4479
4480   if (DECL_P (*node))
4481     {
4482       decl = *node;
4483       type = &TREE_TYPE (decl);
4484       is_type = TREE_CODE (*node) == TYPE_DECL;
4485     }
4486   else if (TYPE_P (*node))
4487     type = node, is_type = 1;
4488
4489   if (TREE_CODE (align_expr) != INTEGER_CST)
4490     {
4491       error ("requested alignment is not a constant");
4492       *no_add_attrs = true;
4493     }
4494   else if ((i = tree_log2 (align_expr)) == -1)
4495     {
4496       error ("requested alignment is not a power of 2");
4497       *no_add_attrs = true;
4498     }
4499   else if (i > HOST_BITS_PER_INT - 2)
4500     {
4501       error ("requested alignment is too large");
4502       *no_add_attrs = true;
4503     }
4504   else if (is_type)
4505     {
4506       /* If we have a TYPE_DECL, then copy the type, so that we
4507          don't accidentally modify a builtin type.  See pushdecl.  */
4508       if (decl && TREE_TYPE (decl) != error_mark_node
4509           && DECL_ORIGINAL_TYPE (decl) == NULL_TREE)
4510         {
4511           tree tt = TREE_TYPE (decl);
4512           *type = build_variant_type_copy (*type);
4513           DECL_ORIGINAL_TYPE (decl) = tt;
4514           TYPE_NAME (*type) = decl;
4515           TREE_USED (*type) = TREE_USED (decl);
4516           TREE_TYPE (decl) = *type;
4517         }
4518       else if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
4519         *type = build_variant_type_copy (*type);
4520
4521       TYPE_ALIGN (*type) = (1 << i) * BITS_PER_UNIT;
4522       TYPE_USER_ALIGN (*type) = 1;
4523     }
4524   else if (TREE_CODE (decl) != VAR_DECL
4525            && TREE_CODE (decl) != FIELD_DECL)
4526     {
4527       error ("%Jalignment may not be specified for %qD", decl, decl);
4528       *no_add_attrs = true;
4529     }
4530   else
4531     {
4532       DECL_ALIGN (decl) = (1 << i) * BITS_PER_UNIT;
4533       DECL_USER_ALIGN (decl) = 1;
4534     }
4535
4536   return NULL_TREE;
4537 }
4538
4539 /* Handle a "weak" attribute; arguments as in
4540    struct attribute_spec.handler.  */
4541
4542 static tree
4543 handle_weak_attribute (tree *node, tree ARG_UNUSED (name),
4544                        tree ARG_UNUSED (args),
4545                        int ARG_UNUSED (flags),
4546                        bool * ARG_UNUSED (no_add_attrs))
4547 {
4548   declare_weak (*node);
4549
4550   return NULL_TREE;
4551 }
4552
4553 /* Handle an "alias" attribute; arguments as in
4554    struct attribute_spec.handler.  */
4555
4556 static tree
4557 handle_alias_attribute (tree *node, tree name, tree args,
4558                         int ARG_UNUSED (flags), bool *no_add_attrs)
4559 {
4560   tree decl = *node;
4561
4562   if ((TREE_CODE (decl) == FUNCTION_DECL && DECL_INITIAL (decl))
4563       || (TREE_CODE (decl) != FUNCTION_DECL && !DECL_EXTERNAL (decl)))
4564     {
4565       error ("%J%qD defined both normally and as an alias", decl, decl);
4566       *no_add_attrs = true;
4567     }
4568
4569   /* Note that the very first time we process a nested declaration,
4570      decl_function_context will not be set.  Indeed, *would* never
4571      be set except for the DECL_INITIAL/DECL_EXTERNAL frobbery that
4572      we do below.  After such frobbery, pushdecl would set the context.
4573      In any case, this is never what we want.  */
4574   else if (decl_function_context (decl) == 0 && current_function_decl == NULL)
4575     {
4576       tree id;
4577
4578       id = TREE_VALUE (args);
4579       if (TREE_CODE (id) != STRING_CST)
4580         {
4581           error ("alias argument not a string");
4582           *no_add_attrs = true;
4583           return NULL_TREE;
4584         }
4585       id = get_identifier (TREE_STRING_POINTER (id));
4586       /* This counts as a use of the object pointed to.  */
4587       TREE_USED (id) = 1;
4588
4589       if (TREE_CODE (decl) == FUNCTION_DECL)
4590         DECL_INITIAL (decl) = error_mark_node;
4591       else
4592         {
4593           DECL_EXTERNAL (decl) = 0;
4594           TREE_STATIC (decl) = 1;
4595         }
4596     }
4597   else
4598     {
4599       warning ("%qE attribute ignored", name);
4600       *no_add_attrs = true;
4601     }
4602
4603   return NULL_TREE;
4604 }
4605
4606 /* Handle an "visibility" attribute; arguments as in
4607    struct attribute_spec.handler.  */
4608
4609 static tree
4610 handle_visibility_attribute (tree *node, tree name, tree args,
4611                              int ARG_UNUSED (flags),
4612                              bool *no_add_attrs)
4613 {
4614   tree decl = *node;
4615   tree id = TREE_VALUE (args);
4616
4617   *no_add_attrs = true;
4618
4619   if (TYPE_P (*node))
4620     {
4621       if (TREE_CODE (*node) != RECORD_TYPE && TREE_CODE (*node) != UNION_TYPE)
4622        {
4623          warning ("%qE attribute ignored on non-class types", name);
4624          return NULL_TREE;
4625        }
4626     }
4627   else if (decl_function_context (decl) != 0 || !TREE_PUBLIC (decl))
4628     {
4629       warning ("%qE attribute ignored", name);
4630       return NULL_TREE;
4631     }
4632
4633   if (TREE_CODE (id) != STRING_CST)
4634     {
4635       error ("visibility argument not a string");
4636       return NULL_TREE;
4637     }
4638
4639   /*  If this is a type, set the visibility on the type decl.  */
4640   if (TYPE_P (decl))
4641     {
4642       decl = TYPE_NAME (decl);
4643       if (!decl)
4644         return NULL_TREE;
4645       if (TREE_CODE (decl) == IDENTIFIER_NODE)
4646         {
4647            warning ("%qE attribute ignored on types",
4648                     name);
4649            return NULL_TREE;
4650         }
4651     }
4652
4653   if (strcmp (TREE_STRING_POINTER (id), "default") == 0)
4654     DECL_VISIBILITY (decl) = VISIBILITY_DEFAULT;
4655   else if (strcmp (TREE_STRING_POINTER (id), "internal") == 0)
4656     DECL_VISIBILITY (decl) = VISIBILITY_INTERNAL;
4657   else if (strcmp (TREE_STRING_POINTER (id), "hidden") == 0)
4658     DECL_VISIBILITY (decl) = VISIBILITY_HIDDEN;
4659   else if (strcmp (TREE_STRING_POINTER (id), "protected") == 0)
4660     DECL_VISIBILITY (decl) = VISIBILITY_PROTECTED;
4661   else
4662     error ("visibility argument must be one of \"default\", \"hidden\", \"protected\" or \"internal\"");
4663   DECL_VISIBILITY_SPECIFIED (decl) = 1;
4664
4665   /* For decls only, go ahead and attach the attribute to the node as well.
4666      This is needed so we can determine whether we have VISIBILITY_DEFAULT
4667      because the visibility was not specified, or because it was explicitly
4668      overridden from the class visibility.  */
4669   if (DECL_P (*node))
4670     *no_add_attrs = false;
4671
4672   return NULL_TREE;
4673 }
4674
4675 /* Determine the ELF symbol visibility for DECL, which is either a
4676    variable or a function.  It is an error to use this function if a
4677    definition of DECL is not available in this translation unit.
4678    Returns true if the final visibility has been determined by this
4679    function; false if the caller is free to make additional
4680    modifications.  */
4681
4682 bool
4683 c_determine_visibility (tree decl)
4684 {
4685   gcc_assert (TREE_CODE (decl) == VAR_DECL
4686               || TREE_CODE (decl) == FUNCTION_DECL);
4687
4688   /* If the user explicitly specified the visibility with an
4689      attribute, honor that.  DECL_VISIBILITY will have been set during
4690      the processing of the attribute.  We check for an explicit
4691      attribute, rather than just checking DECL_VISIBILITY_SPECIFIED,
4692      to distinguish the use of an attribute from the use of a "#pragma
4693      GCC visibility push(...)"; in the latter case we still want other
4694      considerations to be able to overrule the #pragma.  */
4695   if (lookup_attribute ("visibility", DECL_ATTRIBUTES (decl)))
4696     return true;
4697
4698   /* Anything that is exported must have default visibility.  */
4699   if (TARGET_DLLIMPORT_DECL_ATTRIBUTES
4700       && lookup_attribute ("dllexport", DECL_ATTRIBUTES (decl)))
4701     {
4702       DECL_VISIBILITY (decl) = VISIBILITY_DEFAULT;
4703       DECL_VISIBILITY_SPECIFIED (decl) = 1;
4704       return true;
4705     }
4706
4707   return false;
4708 }
4709
4710 /* Handle an "tls_model" attribute; arguments as in
4711    struct attribute_spec.handler.  */
4712
4713 static tree
4714 handle_tls_model_attribute (tree *node, tree name, tree args,
4715                             int ARG_UNUSED (flags), bool *no_add_attrs)
4716 {
4717   tree decl = *node;
4718
4719   if (!DECL_THREAD_LOCAL (decl))
4720     {
4721       warning ("%qE attribute ignored", name);
4722       *no_add_attrs = true;
4723     }
4724   else
4725     {
4726       tree id;
4727
4728       id = TREE_VALUE (args);
4729       if (TREE_CODE (id) != STRING_CST)
4730         {
4731           error ("tls_model argument not a string");
4732           *no_add_attrs = true;
4733           return NULL_TREE;
4734         }
4735       if (strcmp (TREE_STRING_POINTER (id), "local-exec")
4736           && strcmp (TREE_STRING_POINTER (id), "initial-exec")
4737           && strcmp (TREE_STRING_POINTER (id), "local-dynamic")
4738           && strcmp (TREE_STRING_POINTER (id), "global-dynamic"))
4739         {
4740           error ("tls_model argument must be one of \"local-exec\", \"initial-exec\", \"local-dynamic\" or \"global-dynamic\"");
4741           *no_add_attrs = true;
4742           return NULL_TREE;
4743         }
4744     }
4745
4746   return NULL_TREE;
4747 }
4748
4749 /* Handle a "no_instrument_function" attribute; arguments as in
4750    struct attribute_spec.handler.  */
4751
4752 static tree
4753 handle_no_instrument_function_attribute (tree *node, tree name,
4754                                          tree ARG_UNUSED (args),
4755                                          int ARG_UNUSED (flags),
4756                                          bool *no_add_attrs)
4757 {
4758   tree decl = *node;
4759
4760   if (TREE_CODE (decl) != FUNCTION_DECL)
4761     {
4762       error ("%J%qE attribute applies only to functions", decl, name);
4763       *no_add_attrs = true;
4764     }
4765   else if (DECL_INITIAL (decl))
4766     {
4767       error ("%Jcan%'t set %qE attribute after definition", decl, name);
4768       *no_add_attrs = true;
4769     }
4770   else
4771     DECL_NO_INSTRUMENT_FUNCTION_ENTRY_EXIT (decl) = 1;
4772
4773   return NULL_TREE;
4774 }
4775
4776 /* Handle a "malloc" attribute; arguments as in
4777    struct attribute_spec.handler.  */
4778
4779 static tree
4780 handle_malloc_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4781                          int ARG_UNUSED (flags), bool *no_add_attrs)
4782 {
4783   if (TREE_CODE (*node) == FUNCTION_DECL)
4784     DECL_IS_MALLOC (*node) = 1;
4785   /* ??? TODO: Support types.  */
4786   else
4787     {
4788       warning ("%qE attribute ignored", name);
4789       *no_add_attrs = true;
4790     }
4791
4792   return NULL_TREE;
4793 }
4794
4795 /* Handle a "returns_twice" attribute; arguments as in
4796    struct attribute_spec.handler.  */
4797
4798 static tree
4799 handle_returns_twice_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4800                          int ARG_UNUSED (flags), bool *no_add_attrs)
4801 {
4802   if (TREE_CODE (*node) == FUNCTION_DECL)
4803     DECL_IS_RETURNS_TWICE (*node) = 1;
4804   else
4805     {
4806       warning ("%qE attribute ignored", name);
4807       *no_add_attrs = true;
4808     }
4809
4810   return NULL_TREE;
4811 }
4812
4813 /* Handle a "no_limit_stack" attribute; arguments as in
4814    struct attribute_spec.handler.  */
4815
4816 static tree
4817 handle_no_limit_stack_attribute (tree *node, tree name,
4818                                  tree ARG_UNUSED (args),
4819                                  int ARG_UNUSED (flags),
4820                                  bool *no_add_attrs)
4821 {
4822   tree decl = *node;
4823
4824   if (TREE_CODE (decl) != FUNCTION_DECL)
4825     {
4826       error ("%J%qE attribute applies only to functions", decl, name);
4827       *no_add_attrs = true;
4828     }
4829   else if (DECL_INITIAL (decl))
4830     {
4831       error ("%Jcan%'t set %qE attribute after definition", decl, name);
4832       *no_add_attrs = true;
4833     }
4834   else
4835     DECL_NO_LIMIT_STACK (decl) = 1;
4836
4837   return NULL_TREE;
4838 }
4839
4840 /* Handle a "pure" attribute; arguments as in
4841    struct attribute_spec.handler.  */
4842
4843 static tree
4844 handle_pure_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4845                        int ARG_UNUSED (flags), bool *no_add_attrs)
4846 {
4847   if (TREE_CODE (*node) == FUNCTION_DECL)
4848     DECL_IS_PURE (*node) = 1;
4849   /* ??? TODO: Support types.  */
4850   else
4851     {
4852       warning ("%qE attribute ignored", name);
4853       *no_add_attrs = true;
4854     }
4855
4856   return NULL_TREE;
4857 }
4858
4859 /* Handle a "no vops" attribute; arguments as in
4860    struct attribute_spec.handler.  */
4861
4862 static tree
4863 handle_novops_attribute (tree *node, tree ARG_UNUSED (name),
4864                          tree ARG_UNUSED (args), int ARG_UNUSED (flags),
4865                          bool *ARG_UNUSED (no_add_attrs))
4866 {
4867   gcc_assert (TREE_CODE (*node) == FUNCTION_DECL);
4868   DECL_IS_NOVOPS (*node) = 1;
4869   return NULL_TREE;
4870 }
4871
4872 /* Handle a "deprecated" attribute; arguments as in
4873    struct attribute_spec.handler.  */
4874
4875 static tree
4876 handle_deprecated_attribute (tree *node, tree name,
4877                              tree ARG_UNUSED (args), int flags,
4878                              bool *no_add_attrs)
4879 {
4880   tree type = NULL_TREE;
4881   int warn = 0;
4882   tree what = NULL_TREE;
4883
4884   if (DECL_P (*node))
4885     {
4886       tree decl = *node;
4887       type = TREE_TYPE (decl);
4888
4889       if (TREE_CODE (decl) == TYPE_DECL
4890           || TREE_CODE (decl) == PARM_DECL
4891           || TREE_CODE (decl) == VAR_DECL
4892           || TREE_CODE (decl) == FUNCTION_DECL
4893           || TREE_CODE (decl) == FIELD_DECL)
4894         TREE_DEPRECATED (decl) = 1;
4895       else
4896         warn = 1;
4897     }
4898   else if (TYPE_P (*node))
4899     {
4900       if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
4901         *node = build_variant_type_copy (*node);
4902       TREE_DEPRECATED (*node) = 1;
4903       type = *node;
4904     }
4905   else
4906     warn = 1;
4907
4908   if (warn)
4909     {
4910       *no_add_attrs = true;
4911       if (type && TYPE_NAME (type))
4912         {
4913           if (TREE_CODE (TYPE_NAME (type)) == IDENTIFIER_NODE)
4914             what = TYPE_NAME (*node);
4915           else if (TREE_CODE (TYPE_NAME (type)) == TYPE_DECL
4916                    && DECL_NAME (TYPE_NAME (type)))
4917             what = DECL_NAME (TYPE_NAME (type));
4918         }
4919       if (what)
4920         warning ("%qE attribute ignored for %qE", name, what);
4921       else
4922         warning ("%qE attribute ignored", name);
4923     }
4924
4925   return NULL_TREE;
4926 }
4927
4928 /* Handle a "vector_size" attribute; arguments as in
4929    struct attribute_spec.handler.  */
4930
4931 static tree
4932 handle_vector_size_attribute (tree *node, tree name, tree args,
4933                               int ARG_UNUSED (flags),
4934                               bool *no_add_attrs)
4935 {
4936   unsigned HOST_WIDE_INT vecsize, nunits;
4937   enum machine_mode orig_mode;
4938   tree type = *node, new_type, size;
4939
4940   *no_add_attrs = true;
4941
4942   size = TREE_VALUE (args);
4943
4944   if (!host_integerp (size, 1))
4945     {
4946       warning ("%qE attribute ignored", name);
4947       return NULL_TREE;
4948     }
4949
4950   /* Get the vector size (in bytes).  */
4951   vecsize = tree_low_cst (size, 1);
4952
4953   /* We need to provide for vector pointers, vector arrays, and
4954      functions returning vectors.  For example:
4955
4956        __attribute__((vector_size(16))) short *foo;
4957
4958      In this case, the mode is SI, but the type being modified is
4959      HI, so we need to look further.  */
4960
4961   while (POINTER_TYPE_P (type)
4962          || TREE_CODE (type) == FUNCTION_TYPE
4963          || TREE_CODE (type) == METHOD_TYPE
4964          || TREE_CODE (type) == ARRAY_TYPE)
4965     type = TREE_TYPE (type);
4966
4967   /* Get the mode of the type being modified.  */
4968   orig_mode = TYPE_MODE (type);
4969
4970   if (TREE_CODE (type) == RECORD_TYPE
4971       || (GET_MODE_CLASS (orig_mode) != MODE_FLOAT
4972           && GET_MODE_CLASS (orig_mode) != MODE_INT)
4973       || !host_integerp (TYPE_SIZE_UNIT (type), 1))
4974     {
4975       error ("invalid vector type for attribute %qE", name);
4976       return NULL_TREE;
4977     }
4978
4979   /* Calculate how many units fit in the vector.  */
4980   nunits = vecsize / tree_low_cst (TYPE_SIZE_UNIT (type), 1);
4981   if (nunits & (nunits - 1))
4982     {
4983       error ("number of components of the vector not a power of two");
4984       return NULL_TREE;
4985     }
4986
4987   new_type = build_vector_type (type, nunits);
4988
4989   /* Build back pointers if needed.  */
4990   *node = reconstruct_complex_type (*node, new_type);
4991
4992   return NULL_TREE;
4993 }
4994
4995 /* Handle the "nonnull" attribute.  */
4996 static tree
4997 handle_nonnull_attribute (tree *node, tree ARG_UNUSED (name),
4998                           tree args, int ARG_UNUSED (flags),
4999                           bool *no_add_attrs)
5000 {
5001   tree type = *node;
5002   unsigned HOST_WIDE_INT attr_arg_num;
5003
5004   /* If no arguments are specified, all pointer arguments should be
5005      non-null.  Verify a full prototype is given so that the arguments
5006      will have the correct types when we actually check them later.  */
5007   if (!args)
5008     {
5009       if (!TYPE_ARG_TYPES (type))
5010         {
5011           error ("nonnull attribute without arguments on a non-prototype");
5012           *no_add_attrs = true;
5013         }
5014       return NULL_TREE;
5015     }
5016
5017   /* Argument list specified.  Verify that each argument number references
5018      a pointer argument.  */
5019   for (attr_arg_num = 1; args; args = TREE_CHAIN (args))
5020     {
5021       tree argument;
5022       unsigned HOST_WIDE_INT arg_num = 0, ck_num;
5023
5024       if (!get_nonnull_operand (TREE_VALUE (args), &arg_num))
5025         {
5026           error ("nonnull argument has invalid operand number (argument %lu)",
5027                  (unsigned long) attr_arg_num);
5028           *no_add_attrs = true;
5029           return NULL_TREE;
5030         }
5031
5032       argument = TYPE_ARG_TYPES (type);
5033       if (argument)
5034         {
5035           for (ck_num = 1; ; ck_num++)
5036             {
5037               if (!argument || ck_num == arg_num)
5038                 break;
5039               argument = TREE_CHAIN (argument);
5040             }
5041
5042           if (!argument
5043               || TREE_CODE (TREE_VALUE (argument)) == VOID_TYPE)
5044             {
5045               error ("nonnull argument with out-of-range operand number (argument %lu, operand %lu)",
5046                      (unsigned long) attr_arg_num, (unsigned long) arg_num);
5047               *no_add_attrs = true;
5048               return NULL_TREE;
5049             }
5050
5051           if (TREE_CODE (TREE_VALUE (argument)) != POINTER_TYPE)
5052             {
5053               error ("nonnull argument references non-pointer operand (argument %lu, operand %lu)",
5054                    (unsigned long) attr_arg_num, (unsigned long) arg_num);
5055               *no_add_attrs = true;
5056               return NULL_TREE;
5057             }
5058         }
5059     }
5060
5061   return NULL_TREE;
5062 }
5063
5064 /* Check the argument list of a function call for null in argument slots
5065    that are marked as requiring a non-null pointer argument.  */
5066
5067 static void
5068 check_function_nonnull (tree attrs, tree params)
5069 {
5070   tree a, args, param;
5071   int param_num;
5072
5073   for (a = attrs; a; a = TREE_CHAIN (a))
5074     {
5075       if (is_attribute_p ("nonnull", TREE_PURPOSE (a)))
5076         {
5077           args = TREE_VALUE (a);
5078
5079           /* Walk the argument list.  If we encounter an argument number we
5080              should check for non-null, do it.  If the attribute has no args,
5081              then every pointer argument is checked (in which case the check
5082              for pointer type is done in check_nonnull_arg).  */
5083           for (param = params, param_num = 1; ;
5084                param_num++, param = TREE_CHAIN (param))
5085             {
5086               if (!param)
5087         break;
5088               if (!args || nonnull_check_p (args, param_num))
5089         check_function_arguments_recurse (check_nonnull_arg, NULL,
5090                                           TREE_VALUE (param),
5091                                           param_num);
5092             }
5093         }
5094     }
5095 }
5096
5097 /* Check that the Nth argument of a function call (counting backwards
5098    from the end) is a (pointer)0.  */
5099
5100 static void
5101 check_function_sentinel (tree attrs, tree params)
5102 {
5103   tree attr = lookup_attribute ("sentinel", attrs);
5104
5105   if (attr)
5106     {
5107       if (!params)
5108         warning ("missing sentinel in function call");
5109       else
5110         {
5111           tree sentinel, end;
5112           unsigned pos = 0;
5113
5114           if (TREE_VALUE (attr))
5115             {
5116               tree p = TREE_VALUE (TREE_VALUE (attr));
5117               pos = TREE_INT_CST_LOW (p);
5118             }
5119
5120           sentinel = end = params;
5121
5122           /* Advance `end' ahead of `sentinel' by `pos' positions.  */
5123           while (pos > 0 && TREE_CHAIN (end))
5124             {
5125               pos--;
5126               end = TREE_CHAIN (end);
5127             }
5128           if (pos > 0)
5129             {
5130               warning ("not enough arguments to fit a sentinel");
5131               return;
5132             }
5133
5134           /* Now advance both until we find the last parameter.  */
5135           while (TREE_CHAIN (end))
5136             {
5137               end = TREE_CHAIN (end);
5138               sentinel = TREE_CHAIN (sentinel);
5139             }
5140
5141           /* Validate the sentinel.  */
5142           if (!POINTER_TYPE_P (TREE_TYPE (TREE_VALUE (sentinel)))
5143               || !integer_zerop (TREE_VALUE (sentinel)))
5144             warning ("missing sentinel in function call");
5145         }
5146     }
5147 }
5148
5149 /* Helper for check_function_nonnull; given a list of operands which
5150    must be non-null in ARGS, determine if operand PARAM_NUM should be
5151    checked.  */
5152
5153 static bool
5154 nonnull_check_p (tree args, unsigned HOST_WIDE_INT param_num)
5155 {
5156   unsigned HOST_WIDE_INT arg_num = 0;
5157
5158   for (; args; args = TREE_CHAIN (args))
5159     {
5160       bool found = get_nonnull_operand (TREE_VALUE (args), &arg_num);
5161
5162       gcc_assert (found);
5163
5164       if (arg_num == param_num)
5165         return true;
5166     }
5167   return false;
5168 }
5169
5170 /* Check that the function argument PARAM (which is operand number
5171    PARAM_NUM) is non-null.  This is called by check_function_nonnull
5172    via check_function_arguments_recurse.  */
5173
5174 static void
5175 check_nonnull_arg (void * ARG_UNUSED (ctx), tree param,
5176                    unsigned HOST_WIDE_INT param_num)
5177 {
5178   /* Just skip checking the argument if it's not a pointer.  This can
5179      happen if the "nonnull" attribute was given without an operand
5180      list (which means to check every pointer argument).  */
5181
5182   if (TREE_CODE (TREE_TYPE (param)) != POINTER_TYPE)
5183     return;
5184
5185   if (integer_zerop (param))
5186     warning ("null argument where non-null required (argument %lu)",
5187              (unsigned long) param_num);
5188 }
5189
5190 /* Helper for nonnull attribute handling; fetch the operand number
5191    from the attribute argument list.  */
5192
5193 static bool
5194 get_nonnull_operand (tree arg_num_expr, unsigned HOST_WIDE_INT *valp)
5195 {
5196   /* Verify the arg number is a constant.  */
5197   if (TREE_CODE (arg_num_expr) != INTEGER_CST
5198       || TREE_INT_CST_HIGH (arg_num_expr) != 0)
5199     return false;
5200
5201   *valp = TREE_INT_CST_LOW (arg_num_expr);
5202   return true;
5203 }
5204
5205 /* Handle a "nothrow" attribute; arguments as in
5206    struct attribute_spec.handler.  */
5207
5208 static tree
5209 handle_nothrow_attribute (tree *node, tree name, tree ARG_UNUSED (args),
5210                           int ARG_UNUSED (flags), bool *no_add_attrs)
5211 {
5212   if (TREE_CODE (*node) == FUNCTION_DECL)
5213     TREE_NOTHROW (*node) = 1;
5214   /* ??? TODO: Support types.  */
5215   else
5216     {
5217       warning ("%qE attribute ignored", name);
5218       *no_add_attrs = true;
5219     }
5220
5221   return NULL_TREE;
5222 }
5223
5224 /* Handle a "cleanup" attribute; arguments as in
5225    struct attribute_spec.handler.  */
5226
5227 static tree
5228 handle_cleanup_attribute (tree *node, tree name, tree args,
5229                           int ARG_UNUSED (flags), bool *no_add_attrs)
5230 {
5231   tree decl = *node;
5232   tree cleanup_id, cleanup_decl;
5233
5234   /* ??? Could perhaps support cleanups on TREE_STATIC, much like we do
5235      for global destructors in C++.  This requires infrastructure that
5236      we don't have generically at the moment.  It's also not a feature
5237      we'd be missing too much, since we do have attribute constructor.  */
5238   if (TREE_CODE (decl) != VAR_DECL || TREE_STATIC (decl))
5239     {
5240       warning ("%qE attribute ignored", name);
5241       *no_add_attrs = true;
5242       return NULL_TREE;
5243     }
5244
5245   /* Verify that the argument is a function in scope.  */
5246   /* ??? We could support pointers to functions here as well, if
5247      that was considered desirable.  */
5248   cleanup_id = TREE_VALUE (args);
5249   if (TREE_CODE (cleanup_id) != IDENTIFIER_NODE)
5250     {
5251       error ("cleanup argument not an identifier");
5252       *no_add_attrs = true;
5253       return NULL_TREE;
5254     }
5255   cleanup_decl = lookup_name (cleanup_id);
5256   if (!cleanup_decl || TREE_CODE (cleanup_decl) != FUNCTION_DECL)
5257     {
5258       error ("cleanup argument not a function");
5259       *no_add_attrs = true;
5260       return NULL_TREE;
5261     }
5262
5263   /* That the function has proper type is checked with the
5264      eventual call to build_function_call.  */
5265
5266   return NULL_TREE;
5267 }
5268
5269 /* Handle a "warn_unused_result" attribute.  No special handling.  */
5270
5271 static tree
5272 handle_warn_unused_result_attribute (tree *node, tree name,
5273                                tree ARG_UNUSED (args),
5274                                int ARG_UNUSED (flags), bool *no_add_attrs)
5275 {
5276   /* Ignore the attribute for functions not returning any value.  */
5277   if (VOID_TYPE_P (TREE_TYPE (*node)))
5278     {
5279       warning ("%qE attribute ignored", name);
5280       *no_add_attrs = true;
5281     }
5282
5283   return NULL_TREE;
5284 }
5285
5286 /* Handle a "sentinel" attribute.  */
5287
5288 static tree
5289 handle_sentinel_attribute (tree *node, tree name, tree args,
5290                            int ARG_UNUSED (flags), bool *no_add_attrs)
5291 {
5292   tree params = TYPE_ARG_TYPES (*node);
5293
5294   if (!params)
5295     {
5296       warning ("%qE attribute requires prototypes with named arguments", name);
5297       *no_add_attrs = true;
5298     }
5299   else
5300     {
5301       while (TREE_CHAIN (params))
5302         params = TREE_CHAIN (params);
5303
5304       if (VOID_TYPE_P (TREE_VALUE (params)))
5305         {
5306           warning ("%qE attribute only applies to variadic functions", name);
5307           *no_add_attrs = true;
5308         }
5309     }
5310
5311   if (args)
5312     {
5313       tree position = TREE_VALUE (args);
5314
5315       if (TREE_CODE (position) != INTEGER_CST)
5316         {
5317           warning ("requested position is not an integer constant");
5318           *no_add_attrs = true;
5319         }
5320       else
5321         {
5322           if (tree_int_cst_lt (position, integer_zero_node))
5323             {
5324               warning ("requested position is less than zero");
5325               *no_add_attrs = true;
5326             }
5327         }
5328     }
5329
5330   return NULL_TREE;
5331 }
5332 \f
5333 /* Check for valid arguments being passed to a function.  */
5334 void
5335 check_function_arguments (tree attrs, tree params)
5336 {
5337   /* Check for null being passed in a pointer argument that must be
5338      non-null.  We also need to do this if format checking is enabled.  */
5339
5340   if (warn_nonnull)
5341     check_function_nonnull (attrs, params);
5342
5343   /* Check for errors in format strings.  */
5344
5345   if (warn_format)
5346     {
5347       check_function_format (attrs, params);
5348       check_function_sentinel (attrs, params);
5349     }
5350 }
5351
5352 /* Generic argument checking recursion routine.  PARAM is the argument to
5353    be checked.  PARAM_NUM is the number of the argument.  CALLBACK is invoked
5354    once the argument is resolved.  CTX is context for the callback.  */
5355 void
5356 check_function_arguments_recurse (void (*callback)
5357                                   (void *, tree, unsigned HOST_WIDE_INT),
5358                                   void *ctx, tree param,
5359                                   unsigned HOST_WIDE_INT param_num)
5360 {
5361   if (TREE_CODE (param) == NOP_EXPR)
5362     {
5363       /* Strip coercion.  */
5364       check_function_arguments_recurse (callback, ctx,
5365                                         TREE_OPERAND (param, 0), param_num);
5366       return;
5367     }
5368
5369   if (TREE_CODE (param) == CALL_EXPR)
5370     {
5371       tree type = TREE_TYPE (TREE_TYPE (TREE_OPERAND (param, 0)));
5372       tree attrs;
5373       bool found_format_arg = false;
5374
5375       /* See if this is a call to a known internationalization function
5376          that modifies a format arg.  Such a function may have multiple
5377          format_arg attributes (for example, ngettext).  */
5378
5379       for (attrs = TYPE_ATTRIBUTES (type);
5380            attrs;
5381            attrs = TREE_CHAIN (attrs))
5382         if (is_attribute_p ("format_arg", TREE_PURPOSE (attrs)))
5383           {
5384             tree inner_args;
5385             tree format_num_expr;
5386             int format_num;
5387             int i;
5388
5389             /* Extract the argument number, which was previously checked
5390                to be valid.  */
5391             format_num_expr = TREE_VALUE (TREE_VALUE (attrs));
5392
5393             gcc_assert (TREE_CODE (format_num_expr) == INTEGER_CST
5394                         && !TREE_INT_CST_HIGH (format_num_expr));
5395
5396             format_num = TREE_INT_CST_LOW (format_num_expr);
5397
5398             for (inner_args = TREE_OPERAND (param, 1), i = 1;
5399                  inner_args != 0;
5400                  inner_args = TREE_CHAIN (inner_args), i++)
5401               if (i == format_num)
5402                 {
5403                   check_function_arguments_recurse (callback, ctx,
5404                                                     TREE_VALUE (inner_args),
5405                                                     param_num);
5406                   found_format_arg = true;
5407                   break;
5408                 }
5409           }
5410
5411       /* If we found a format_arg attribute and did a recursive check,
5412          we are done with checking this argument.  Otherwise, we continue
5413          and this will be considered a non-literal.  */
5414       if (found_format_arg)
5415         return;
5416     }
5417
5418   if (TREE_CODE (param) == COND_EXPR)
5419     {
5420       /* Check both halves of the conditional expression.  */
5421       check_function_arguments_recurse (callback, ctx,
5422                                         TREE_OPERAND (param, 1), param_num);
5423       check_function_arguments_recurse (callback, ctx,
5424                                         TREE_OPERAND (param, 2), param_num);
5425       return;
5426     }
5427
5428   (*callback) (ctx, param, param_num);
5429 }
5430
5431 /* Function to help qsort sort FIELD_DECLs by name order.  */
5432
5433 int
5434 field_decl_cmp (const void *x_p, const void *y_p)
5435 {
5436   const tree *const x = (const tree *const) x_p;
5437   const tree *const y = (const tree *const) y_p;
5438
5439   if (DECL_NAME (*x) == DECL_NAME (*y))
5440     /* A nontype is "greater" than a type.  */
5441     return (TREE_CODE (*y) == TYPE_DECL) - (TREE_CODE (*x) == TYPE_DECL);
5442   if (DECL_NAME (*x) == NULL_TREE)
5443     return -1;
5444   if (DECL_NAME (*y) == NULL_TREE)
5445     return 1;
5446   if (DECL_NAME (*x) < DECL_NAME (*y))
5447     return -1;
5448   return 1;
5449 }
5450
5451 static struct {
5452   gt_pointer_operator new_value;
5453   void *cookie;
5454 } resort_data;
5455
5456 /* This routine compares two fields like field_decl_cmp but using the
5457 pointer operator in resort_data.  */
5458
5459 static int
5460 resort_field_decl_cmp (const void *x_p, const void *y_p)
5461 {
5462   const tree *const x = (const tree *const) x_p;
5463   const tree *const y = (const tree *const) y_p;
5464
5465   if (DECL_NAME (*x) == DECL_NAME (*y))
5466     /* A nontype is "greater" than a type.  */
5467     return (TREE_CODE (*y) == TYPE_DECL) - (TREE_CODE (*x) == TYPE_DECL);
5468   if (DECL_NAME (*x) == NULL_TREE)
5469     return -1;
5470   if (DECL_NAME (*y) == NULL_TREE)
5471     return 1;
5472   {
5473     tree d1 = DECL_NAME (*x);
5474     tree d2 = DECL_NAME (*y);
5475     resort_data.new_value (&d1, resort_data.cookie);
5476     resort_data.new_value (&d2, resort_data.cookie);
5477     if (d1 < d2)
5478       return -1;
5479   }
5480   return 1;
5481 }
5482
5483 /* Resort DECL_SORTED_FIELDS because pointers have been reordered.  */
5484
5485 void
5486 resort_sorted_fields (void *obj,
5487                       void * ARG_UNUSED (orig_obj),
5488                       gt_pointer_operator new_value,
5489                       void *cookie)
5490 {
5491   struct sorted_fields_type *sf = (struct sorted_fields_type *) obj;
5492   resort_data.new_value = new_value;
5493   resort_data.cookie = cookie;
5494   qsort (&sf->elts[0], sf->len, sizeof (tree),
5495          resort_field_decl_cmp);
5496 }
5497
5498 /* Subroutine of c_parse_error.
5499    Return the result of concatenating LHS and RHS. RHS is really
5500    a string literal, its first character is indicated by RHS_START and
5501    RHS_SIZE is its length (including the terminating NUL character).
5502
5503    The caller is responsible for deleting the returned pointer.  */
5504
5505 static char *
5506 catenate_strings (const char *lhs, const char *rhs_start, int rhs_size)
5507 {
5508   const int lhs_size = strlen (lhs);
5509   char *result = XNEWVEC (char, lhs_size + rhs_size);
5510   strncpy (result, lhs, lhs_size);
5511   strncpy (result + lhs_size, rhs_start, rhs_size);
5512   return result;
5513 }
5514
5515 /* Issue the error given by MSGID, indicating that it occurred before
5516    TOKEN, which had the associated VALUE.  */
5517
5518 void
5519 c_parse_error (const char *msgid, enum cpp_ttype token, tree value)
5520 {
5521 #define catenate_messages(M1, M2) catenate_strings ((M1), (M2), sizeof (M2))
5522
5523   char *message = NULL;
5524
5525   if (token == CPP_EOF)
5526     message = catenate_messages (msgid, " at end of input");
5527   else if (token == CPP_CHAR || token == CPP_WCHAR)
5528     {
5529       unsigned int val = TREE_INT_CST_LOW (value);
5530       const char *const ell = (token == CPP_CHAR) ? "" : "L";
5531       if (val <= UCHAR_MAX && ISGRAPH (val))
5532         message = catenate_messages (msgid, " before %s'%c'");
5533       else
5534         message = catenate_messages (msgid, " before %s'\\x%x'");
5535
5536       error (message, ell, val);
5537       free (message);
5538       message = NULL;
5539     }
5540   else if (token == CPP_STRING || token == CPP_WSTRING)
5541     message = catenate_messages (msgid, " before string constant");
5542   else if (token == CPP_NUMBER)
5543     message = catenate_messages (msgid, " before numeric constant");
5544   else if (token == CPP_NAME)
5545     {
5546       message = catenate_messages (msgid, " before %qE");
5547       error (message, value);
5548       free (message);
5549       message = NULL;
5550     }
5551   else if (token < N_TTYPES)
5552     {
5553       message = catenate_messages (msgid, " before %qs token");
5554       error (message, cpp_type2name (token));
5555       free (message);
5556       message = NULL;
5557     }
5558   else
5559     error (msgid);
5560
5561   if (message)
5562     {
5563       error (message);
5564       free (message);
5565     }
5566 #undef catenate_messages
5567 }
5568
5569 /* Walk a gimplified function and warn for functions whose return value is
5570    ignored and attribute((warn_unused_result)) is set.  This is done before
5571    inlining, so we don't have to worry about that.  */
5572
5573 void
5574 c_warn_unused_result (tree *top_p)
5575 {
5576   tree t = *top_p;
5577   tree_stmt_iterator i;
5578   tree fdecl, ftype;
5579
5580   switch (TREE_CODE (t))
5581     {
5582     case STATEMENT_LIST:
5583       for (i = tsi_start (*top_p); !tsi_end_p (i); tsi_next (&i))
5584         c_warn_unused_result (tsi_stmt_ptr (i));
5585       break;
5586
5587     case COND_EXPR:
5588       c_warn_unused_result (&COND_EXPR_THEN (t));
5589       c_warn_unused_result (&COND_EXPR_ELSE (t));
5590       break;
5591     case BIND_EXPR:
5592       c_warn_unused_result (&BIND_EXPR_BODY (t));
5593       break;
5594     case TRY_FINALLY_EXPR:
5595     case TRY_CATCH_EXPR:
5596       c_warn_unused_result (&TREE_OPERAND (t, 0));
5597       c_warn_unused_result (&TREE_OPERAND (t, 1));
5598       break;
5599     case CATCH_EXPR:
5600       c_warn_unused_result (&CATCH_BODY (t));
5601       break;
5602     case EH_FILTER_EXPR:
5603       c_warn_unused_result (&EH_FILTER_FAILURE (t));
5604       break;
5605
5606     case CALL_EXPR:
5607       if (TREE_USED (t))
5608         break;
5609
5610       /* This is a naked call, as opposed to a CALL_EXPR nested inside
5611          a MODIFY_EXPR.  All calls whose value is ignored should be
5612          represented like this.  Look for the attribute.  */
5613       fdecl = get_callee_fndecl (t);
5614       if (fdecl)
5615         ftype = TREE_TYPE (fdecl);
5616       else
5617         {
5618           ftype = TREE_TYPE (TREE_OPERAND (t, 0));
5619           /* Look past pointer-to-function to the function type itself.  */
5620           ftype = TREE_TYPE (ftype);
5621         }
5622
5623       if (lookup_attribute ("warn_unused_result", TYPE_ATTRIBUTES (ftype)))
5624         {
5625           if (fdecl)
5626             warning ("%Hignoring return value of %qD, "
5627                      "declared with attribute warn_unused_result",
5628                      EXPR_LOCUS (t), fdecl);
5629           else
5630             warning ("%Hignoring return value of function "
5631                      "declared with attribute warn_unused_result",
5632                      EXPR_LOCUS (t));
5633         }
5634       break;
5635
5636     default:
5637       /* Not a container, not a call, or a call whose value is used.  */
5638       break;
5639     }
5640 }
5641
5642 /* Convert a character from the host to the target execution character
5643    set.  cpplib handles this, mostly.  */
5644
5645 HOST_WIDE_INT
5646 c_common_to_target_charset (HOST_WIDE_INT c)
5647 {
5648   /* Character constants in GCC proper are sign-extended under -fsigned-char,
5649      zero-extended under -fno-signed-char.  cpplib insists that characters
5650      and character constants are always unsigned.  Hence we must convert
5651      back and forth.  */
5652   cppchar_t uc = ((cppchar_t)c) & ((((cppchar_t)1) << CHAR_BIT)-1);
5653
5654   uc = cpp_host_to_exec_charset (parse_in, uc);
5655
5656   if (flag_signed_char)
5657     return ((HOST_WIDE_INT)uc) << (HOST_BITS_PER_WIDE_INT - CHAR_TYPE_SIZE)
5658                                >> (HOST_BITS_PER_WIDE_INT - CHAR_TYPE_SIZE);
5659   else
5660     return uc;
5661 }
5662
5663 /* Build the result of __builtin_offsetof.  EXPR is a nested sequence of
5664    component references, with an INDIRECT_REF at the bottom; much like
5665    the traditional rendering of offsetof as a macro.  Returns the folded
5666    and properly cast result.  */
5667
5668 static tree
5669 fold_offsetof_1 (tree expr)
5670 {
5671   enum tree_code code = PLUS_EXPR;
5672   tree base, off, t;
5673
5674   switch (TREE_CODE (expr))
5675     {
5676     case ERROR_MARK:
5677       return expr;
5678
5679     case INDIRECT_REF:
5680       return size_zero_node;
5681
5682     case COMPONENT_REF:
5683       base = fold_offsetof_1 (TREE_OPERAND (expr, 0));
5684       if (base == error_mark_node)
5685         return base;
5686
5687       t = TREE_OPERAND (expr, 1);
5688       if (DECL_C_BIT_FIELD (t))
5689         {
5690           error ("attempt to take address of bit-field structure "
5691                  "member %qD", t);
5692           return error_mark_node;
5693         }
5694       off = size_binop (PLUS_EXPR, DECL_FIELD_OFFSET (t),
5695                         size_int (tree_low_cst (DECL_FIELD_BIT_OFFSET (t), 1)
5696                                   / BITS_PER_UNIT));
5697       break;
5698
5699     case ARRAY_REF:
5700       base = fold_offsetof_1 (TREE_OPERAND (expr, 0));
5701       if (base == error_mark_node)
5702         return base;
5703
5704       t = TREE_OPERAND (expr, 1);
5705       if (TREE_CODE (t) == INTEGER_CST && tree_int_cst_sgn (t) < 0)
5706         {
5707           code = MINUS_EXPR;
5708           t = fold (build1 (NEGATE_EXPR, TREE_TYPE (t), t));
5709         }
5710       t = convert (sizetype, t);
5711       off = size_binop (MULT_EXPR, TYPE_SIZE_UNIT (TREE_TYPE (expr)), t);
5712       break;
5713
5714     default:
5715       gcc_unreachable ();
5716     }
5717
5718   return size_binop (code, base, off);
5719 }
5720
5721 tree
5722 fold_offsetof (tree expr)
5723 {
5724   /* Convert back from the internal sizetype to size_t.  */
5725   return convert (size_type_node, fold_offsetof_1 (expr));
5726 }
5727
5728 /* Print an error message for an invalid lvalue.  USE says
5729    how the lvalue is being used and so selects the error message.  */
5730
5731 void
5732 lvalue_error (enum lvalue_use use)
5733 {
5734   switch (use)
5735     {
5736     case lv_assign:
5737       error ("invalid lvalue in assignment");
5738       break;
5739     case lv_increment:
5740       error ("invalid lvalue in increment");
5741       break;
5742     case lv_decrement:
5743       error ("invalid lvalue in decrement");
5744       break;
5745     case lv_addressof:
5746       error ("invalid lvalue in unary %<&%>");
5747       break;
5748     case lv_asm:
5749       error ("invalid lvalue in asm statement");
5750       break;
5751     default:
5752       gcc_unreachable ();
5753     }
5754 }
5755
5756 #include "gt-c-common.h"