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     /* Promote char or short to int.  */
1432     value = perform_integral_promotions (value);
1433   else if (value != error_mark_node)
1434     {
1435       error ("case label does not reduce to an integer constant");
1436       value = error_mark_node;
1437     }
1438
1439   constant_expression_warning (value);
1440
1441   return value;
1442 }
1443 \f
1444 /* See if the case values LOW and HIGH are in the range of the original
1445    type (i.e. before the default conversion to int) of the switch testing
1446    expression.
1447    TYPE is the promoted type of the testing expression, and ORIG_TYPE is
1448    the type before promoting it.  CASE_LOW_P is a pointer to the lower
1449    bound of the case label, and CASE_HIGH_P is the upper bound or NULL
1450    if the case is not a case range.
1451    The caller has to make sure that we are not called with NULL for
1452    CASE_LOW_P (i.e. the default case).
1453    Returns true if the case label is in range of ORIG_TYPE (satured or
1454    untouched) or false if the label is out of range.  */
1455
1456 static bool
1457 check_case_bounds (tree type, tree orig_type,
1458                    tree *case_low_p, tree *case_high_p)
1459 {
1460   tree min_value, max_value;
1461   tree case_low = *case_low_p;
1462   tree case_high = case_high_p ? *case_high_p : case_low;
1463
1464   /* If there was a problem with the original type, do nothing.  */
1465   if (orig_type == error_mark_node)
1466     return true;
1467
1468   min_value = TYPE_MIN_VALUE (orig_type);
1469   max_value = TYPE_MAX_VALUE (orig_type);
1470
1471   /* Case label is less than minimum for type.  */
1472   if (tree_int_cst_compare (case_low, min_value) < 0
1473       && tree_int_cst_compare (case_high, min_value) < 0)
1474     {
1475       warning ("case label value is less than minimum value for type");
1476       return false;
1477     }
1478
1479   /* Case value is greater than maximum for type.  */
1480   if (tree_int_cst_compare (case_low, max_value) > 0
1481       && tree_int_cst_compare (case_high, max_value) > 0)
1482     {
1483       warning ("case label value exceeds maximum value for type");
1484       return false;
1485     }
1486
1487   /* Saturate lower case label value to minimum.  */
1488   if (tree_int_cst_compare (case_high, min_value) >= 0
1489       && tree_int_cst_compare (case_low, min_value) < 0)
1490     {
1491       warning ("lower value in case label range"
1492                " less than minimum value for type");
1493       case_low = min_value;
1494     }
1495
1496   /* Saturate upper case label value to maximum.  */
1497   if (tree_int_cst_compare (case_low, max_value) <= 0
1498       && tree_int_cst_compare (case_high, max_value) > 0)
1499     {
1500       warning ("upper value in case label range"
1501                " exceeds maximum value for type");
1502       case_high = max_value;
1503     }
1504
1505   if (*case_low_p != case_low)
1506     *case_low_p = convert (type, case_low);
1507   if (case_high_p && *case_high_p != case_high)
1508     *case_high_p = convert (type, case_high);
1509
1510   return true;
1511 }
1512 \f
1513 /* Return an integer type with BITS bits of precision,
1514    that is unsigned if UNSIGNEDP is nonzero, otherwise signed.  */
1515
1516 tree
1517 c_common_type_for_size (unsigned int bits, int unsignedp)
1518 {
1519   if (bits == TYPE_PRECISION (integer_type_node))
1520     return unsignedp ? unsigned_type_node : integer_type_node;
1521
1522   if (bits == TYPE_PRECISION (signed_char_type_node))
1523     return unsignedp ? unsigned_char_type_node : signed_char_type_node;
1524
1525   if (bits == TYPE_PRECISION (short_integer_type_node))
1526     return unsignedp ? short_unsigned_type_node : short_integer_type_node;
1527
1528   if (bits == TYPE_PRECISION (long_integer_type_node))
1529     return unsignedp ? long_unsigned_type_node : long_integer_type_node;
1530
1531   if (bits == TYPE_PRECISION (long_long_integer_type_node))
1532     return (unsignedp ? long_long_unsigned_type_node
1533             : long_long_integer_type_node);
1534
1535   if (bits == TYPE_PRECISION (widest_integer_literal_type_node))
1536     return (unsignedp ? widest_unsigned_literal_type_node
1537             : widest_integer_literal_type_node);
1538
1539   if (bits <= TYPE_PRECISION (intQI_type_node))
1540     return unsignedp ? unsigned_intQI_type_node : intQI_type_node;
1541
1542   if (bits <= TYPE_PRECISION (intHI_type_node))
1543     return unsignedp ? unsigned_intHI_type_node : intHI_type_node;
1544
1545   if (bits <= TYPE_PRECISION (intSI_type_node))
1546     return unsignedp ? unsigned_intSI_type_node : intSI_type_node;
1547
1548   if (bits <= TYPE_PRECISION (intDI_type_node))
1549     return unsignedp ? unsigned_intDI_type_node : intDI_type_node;
1550
1551   return 0;
1552 }
1553
1554 /* Used for communication between c_common_type_for_mode and
1555    c_register_builtin_type.  */
1556 static GTY(()) tree registered_builtin_types;
1557
1558 /* Return a data type that has machine mode MODE.
1559    If the mode is an integer,
1560    then UNSIGNEDP selects between signed and unsigned types.  */
1561
1562 tree
1563 c_common_type_for_mode (enum machine_mode mode, int unsignedp)
1564 {
1565   tree t;
1566
1567   if (mode == TYPE_MODE (integer_type_node))
1568     return unsignedp ? unsigned_type_node : integer_type_node;
1569
1570   if (mode == TYPE_MODE (signed_char_type_node))
1571     return unsignedp ? unsigned_char_type_node : signed_char_type_node;
1572
1573   if (mode == TYPE_MODE (short_integer_type_node))
1574     return unsignedp ? short_unsigned_type_node : short_integer_type_node;
1575
1576   if (mode == TYPE_MODE (long_integer_type_node))
1577     return unsignedp ? long_unsigned_type_node : long_integer_type_node;
1578
1579   if (mode == TYPE_MODE (long_long_integer_type_node))
1580     return unsignedp ? long_long_unsigned_type_node : long_long_integer_type_node;
1581
1582   if (mode == TYPE_MODE (widest_integer_literal_type_node))
1583     return unsignedp ? widest_unsigned_literal_type_node
1584                      : widest_integer_literal_type_node;
1585
1586   if (mode == QImode)
1587     return unsignedp ? unsigned_intQI_type_node : intQI_type_node;
1588
1589   if (mode == HImode)
1590     return unsignedp ? unsigned_intHI_type_node : intHI_type_node;
1591
1592   if (mode == SImode)
1593     return unsignedp ? unsigned_intSI_type_node : intSI_type_node;
1594
1595   if (mode == DImode)
1596     return unsignedp ? unsigned_intDI_type_node : intDI_type_node;
1597
1598 #if HOST_BITS_PER_WIDE_INT >= 64
1599   if (mode == TYPE_MODE (intTI_type_node))
1600     return unsignedp ? unsigned_intTI_type_node : intTI_type_node;
1601 #endif
1602
1603   if (mode == TYPE_MODE (float_type_node))
1604     return float_type_node;
1605
1606   if (mode == TYPE_MODE (double_type_node))
1607     return double_type_node;
1608
1609   if (mode == TYPE_MODE (long_double_type_node))
1610     return long_double_type_node;
1611
1612   if (mode == TYPE_MODE (void_type_node))
1613     return void_type_node;
1614
1615   if (mode == TYPE_MODE (build_pointer_type (char_type_node)))
1616     return (unsignedp
1617             ? make_unsigned_type (GET_MODE_PRECISION (mode))
1618             : make_signed_type (GET_MODE_PRECISION (mode)));
1619
1620   if (mode == TYPE_MODE (build_pointer_type (integer_type_node)))
1621     return (unsignedp
1622             ? make_unsigned_type (GET_MODE_PRECISION (mode))
1623             : make_signed_type (GET_MODE_PRECISION (mode)));
1624
1625   if (COMPLEX_MODE_P (mode))
1626     {
1627       enum machine_mode inner_mode;
1628       tree inner_type;
1629
1630       if (mode == TYPE_MODE (complex_float_type_node))
1631         return complex_float_type_node;
1632       if (mode == TYPE_MODE (complex_double_type_node))
1633         return complex_double_type_node;
1634       if (mode == TYPE_MODE (complex_long_double_type_node))
1635         return complex_long_double_type_node;
1636
1637       if (mode == TYPE_MODE (complex_integer_type_node) && !unsignedp)
1638         return complex_integer_type_node;
1639
1640       inner_mode = GET_MODE_INNER (mode);
1641       inner_type = c_common_type_for_mode (inner_mode, unsignedp);
1642       if (inner_type != NULL_TREE)
1643         return build_complex_type (inner_type);
1644     }
1645   else if (VECTOR_MODE_P (mode))
1646     {
1647       enum machine_mode inner_mode = GET_MODE_INNER (mode);
1648       tree inner_type = c_common_type_for_mode (inner_mode, unsignedp);
1649       if (inner_type != NULL_TREE)
1650         return build_vector_type_for_mode (inner_type, mode);
1651     }
1652
1653   for (t = registered_builtin_types; t; t = TREE_CHAIN (t))
1654     if (TYPE_MODE (TREE_VALUE (t)) == mode)
1655       return TREE_VALUE (t);
1656
1657   return 0;
1658 }
1659
1660 /* Return an unsigned type the same as TYPE in other respects.  */
1661 tree
1662 c_common_unsigned_type (tree type)
1663 {
1664   tree type1 = TYPE_MAIN_VARIANT (type);
1665   if (type1 == signed_char_type_node || type1 == char_type_node)
1666     return unsigned_char_type_node;
1667   if (type1 == integer_type_node)
1668     return unsigned_type_node;
1669   if (type1 == short_integer_type_node)
1670     return short_unsigned_type_node;
1671   if (type1 == long_integer_type_node)
1672     return long_unsigned_type_node;
1673   if (type1 == long_long_integer_type_node)
1674     return long_long_unsigned_type_node;
1675   if (type1 == widest_integer_literal_type_node)
1676     return widest_unsigned_literal_type_node;
1677 #if HOST_BITS_PER_WIDE_INT >= 64
1678   if (type1 == intTI_type_node)
1679     return unsigned_intTI_type_node;
1680 #endif
1681   if (type1 == intDI_type_node)
1682     return unsigned_intDI_type_node;
1683   if (type1 == intSI_type_node)
1684     return unsigned_intSI_type_node;
1685   if (type1 == intHI_type_node)
1686     return unsigned_intHI_type_node;
1687   if (type1 == intQI_type_node)
1688     return unsigned_intQI_type_node;
1689
1690   return c_common_signed_or_unsigned_type (1, type);
1691 }
1692
1693 /* Return a signed type the same as TYPE in other respects.  */
1694
1695 tree
1696 c_common_signed_type (tree type)
1697 {
1698   tree type1 = TYPE_MAIN_VARIANT (type);
1699   if (type1 == unsigned_char_type_node || type1 == char_type_node)
1700     return signed_char_type_node;
1701   if (type1 == unsigned_type_node)
1702     return integer_type_node;
1703   if (type1 == short_unsigned_type_node)
1704     return short_integer_type_node;
1705   if (type1 == long_unsigned_type_node)
1706     return long_integer_type_node;
1707   if (type1 == long_long_unsigned_type_node)
1708     return long_long_integer_type_node;
1709   if (type1 == widest_unsigned_literal_type_node)
1710     return widest_integer_literal_type_node;
1711 #if HOST_BITS_PER_WIDE_INT >= 64
1712   if (type1 == unsigned_intTI_type_node)
1713     return intTI_type_node;
1714 #endif
1715   if (type1 == unsigned_intDI_type_node)
1716     return intDI_type_node;
1717   if (type1 == unsigned_intSI_type_node)
1718     return intSI_type_node;
1719   if (type1 == unsigned_intHI_type_node)
1720     return intHI_type_node;
1721   if (type1 == unsigned_intQI_type_node)
1722     return intQI_type_node;
1723
1724   return c_common_signed_or_unsigned_type (0, type);
1725 }
1726
1727 /* Return a type the same as TYPE except unsigned or
1728    signed according to UNSIGNEDP.  */
1729
1730 tree
1731 c_common_signed_or_unsigned_type (int unsignedp, tree type)
1732 {
1733   if (!INTEGRAL_TYPE_P (type)
1734       || TYPE_UNSIGNED (type) == unsignedp)
1735     return type;
1736
1737   /* For ENUMERAL_TYPEs in C++, must check the mode of the types, not
1738      the precision; they have precision set to match their range, but
1739      may use a wider mode to match an ABI.  If we change modes, we may
1740      wind up with bad conversions.  For INTEGER_TYPEs in C, must check
1741      the precision as well, so as to yield correct results for
1742      bit-field types.  C++ does not have these separate bit-field
1743      types, and producing a signed or unsigned variant of an
1744      ENUMERAL_TYPE may cause other problems as well.  */
1745
1746 #define TYPE_OK(node)                                                       \
1747   (TYPE_MODE (type) == TYPE_MODE (node)                                     \
1748    && (c_dialect_cxx () || TYPE_PRECISION (type) == TYPE_PRECISION (node)))
1749   if (TYPE_OK (signed_char_type_node))
1750     return unsignedp ? unsigned_char_type_node : signed_char_type_node;
1751   if (TYPE_OK (integer_type_node))
1752     return unsignedp ? unsigned_type_node : integer_type_node;
1753   if (TYPE_OK (short_integer_type_node))
1754     return unsignedp ? short_unsigned_type_node : short_integer_type_node;
1755   if (TYPE_OK (long_integer_type_node))
1756     return unsignedp ? long_unsigned_type_node : long_integer_type_node;
1757   if (TYPE_OK (long_long_integer_type_node))
1758     return (unsignedp ? long_long_unsigned_type_node
1759             : long_long_integer_type_node);
1760   if (TYPE_OK (widest_integer_literal_type_node))
1761     return (unsignedp ? widest_unsigned_literal_type_node
1762             : widest_integer_literal_type_node);
1763
1764 #if HOST_BITS_PER_WIDE_INT >= 64
1765   if (TYPE_OK (intTI_type_node))
1766     return unsignedp ? unsigned_intTI_type_node : intTI_type_node;
1767 #endif
1768   if (TYPE_OK (intDI_type_node))
1769     return unsignedp ? unsigned_intDI_type_node : intDI_type_node;
1770   if (TYPE_OK (intSI_type_node))
1771     return unsignedp ? unsigned_intSI_type_node : intSI_type_node;
1772   if (TYPE_OK (intHI_type_node))
1773     return unsignedp ? unsigned_intHI_type_node : intHI_type_node;
1774   if (TYPE_OK (intQI_type_node))
1775     return unsignedp ? unsigned_intQI_type_node : intQI_type_node;
1776 #undef TYPE_OK
1777
1778   if (c_dialect_cxx ())
1779     return type;
1780   else
1781     return build_nonstandard_integer_type (TYPE_PRECISION (type), unsignedp);
1782 }
1783
1784 /* The C version of the register_builtin_type langhook.  */
1785
1786 void
1787 c_register_builtin_type (tree type, const char* name)
1788 {
1789   tree decl;
1790
1791   decl = build_decl (TYPE_DECL, get_identifier (name), type);
1792   DECL_ARTIFICIAL (decl) = 1;
1793   if (!TYPE_NAME (type))
1794     TYPE_NAME (type) = decl;
1795   pushdecl (decl);
1796
1797   registered_builtin_types = tree_cons (0, type, registered_builtin_types);
1798 }
1799
1800 \f
1801 /* Return the minimum number of bits needed to represent VALUE in a
1802    signed or unsigned type, UNSIGNEDP says which.  */
1803
1804 unsigned int
1805 min_precision (tree value, int unsignedp)
1806 {
1807   int log;
1808
1809   /* If the value is negative, compute its negative minus 1.  The latter
1810      adjustment is because the absolute value of the largest negative value
1811      is one larger than the largest positive value.  This is equivalent to
1812      a bit-wise negation, so use that operation instead.  */
1813
1814   if (tree_int_cst_sgn (value) < 0)
1815     value = fold (build1 (BIT_NOT_EXPR, TREE_TYPE (value), value));
1816
1817   /* Return the number of bits needed, taking into account the fact
1818      that we need one more bit for a signed than unsigned type.  */
1819
1820   if (integer_zerop (value))
1821     log = 0;
1822   else
1823     log = tree_floor_log2 (value);
1824
1825   return log + 1 + !unsignedp;
1826 }
1827 \f
1828 /* Print an error message for invalid operands to arith operation
1829    CODE.  NOP_EXPR is used as a special case (see
1830    c_common_truthvalue_conversion).  */
1831
1832 void
1833 binary_op_error (enum tree_code code)
1834 {
1835   const char *opname;
1836
1837   switch (code)
1838     {
1839     case NOP_EXPR:
1840       error ("invalid truth-value expression");
1841       return;
1842
1843     case PLUS_EXPR:
1844       opname = "+"; break;
1845     case MINUS_EXPR:
1846       opname = "-"; break;
1847     case MULT_EXPR:
1848       opname = "*"; break;
1849     case MAX_EXPR:
1850       opname = "max"; break;
1851     case MIN_EXPR:
1852       opname = "min"; break;
1853     case EQ_EXPR:
1854       opname = "=="; break;
1855     case NE_EXPR:
1856       opname = "!="; break;
1857     case LE_EXPR:
1858       opname = "<="; break;
1859     case GE_EXPR:
1860       opname = ">="; break;
1861     case LT_EXPR:
1862       opname = "<"; break;
1863     case GT_EXPR:
1864       opname = ">"; break;
1865     case LSHIFT_EXPR:
1866       opname = "<<"; break;
1867     case RSHIFT_EXPR:
1868       opname = ">>"; break;
1869     case TRUNC_MOD_EXPR:
1870     case FLOOR_MOD_EXPR:
1871       opname = "%"; break;
1872     case TRUNC_DIV_EXPR:
1873     case FLOOR_DIV_EXPR:
1874       opname = "/"; break;
1875     case BIT_AND_EXPR:
1876       opname = "&"; break;
1877     case BIT_IOR_EXPR:
1878       opname = "|"; break;
1879     case TRUTH_ANDIF_EXPR:
1880       opname = "&&"; break;
1881     case TRUTH_ORIF_EXPR:
1882       opname = "||"; break;
1883     case BIT_XOR_EXPR:
1884       opname = "^"; break;
1885     default:
1886       gcc_unreachable ();
1887     }
1888   error ("invalid operands to binary %s", opname);
1889 }
1890 \f
1891 /* Subroutine of build_binary_op, used for comparison operations.
1892    See if the operands have both been converted from subword integer types
1893    and, if so, perhaps change them both back to their original type.
1894    This function is also responsible for converting the two operands
1895    to the proper common type for comparison.
1896
1897    The arguments of this function are all pointers to local variables
1898    of build_binary_op: OP0_PTR is &OP0, OP1_PTR is &OP1,
1899    RESTYPE_PTR is &RESULT_TYPE and RESCODE_PTR is &RESULTCODE.
1900
1901    If this function returns nonzero, it means that the comparison has
1902    a constant value.  What this function returns is an expression for
1903    that value.  */
1904
1905 tree
1906 shorten_compare (tree *op0_ptr, tree *op1_ptr, tree *restype_ptr,
1907                  enum tree_code *rescode_ptr)
1908 {
1909   tree type;
1910   tree op0 = *op0_ptr;
1911   tree op1 = *op1_ptr;
1912   int unsignedp0, unsignedp1;
1913   int real1, real2;
1914   tree primop0, primop1;
1915   enum tree_code code = *rescode_ptr;
1916
1917   /* Throw away any conversions to wider types
1918      already present in the operands.  */
1919
1920   primop0 = get_narrower (op0, &unsignedp0);
1921   primop1 = get_narrower (op1, &unsignedp1);
1922
1923   /* Handle the case that OP0 does not *contain* a conversion
1924      but it *requires* conversion to FINAL_TYPE.  */
1925
1926   if (op0 == primop0 && TREE_TYPE (op0) != *restype_ptr)
1927     unsignedp0 = TYPE_UNSIGNED (TREE_TYPE (op0));
1928   if (op1 == primop1 && TREE_TYPE (op1) != *restype_ptr)
1929     unsignedp1 = TYPE_UNSIGNED (TREE_TYPE (op1));
1930
1931   /* If one of the operands must be floated, we cannot optimize.  */
1932   real1 = TREE_CODE (TREE_TYPE (primop0)) == REAL_TYPE;
1933   real2 = TREE_CODE (TREE_TYPE (primop1)) == REAL_TYPE;
1934
1935   /* If first arg is constant, swap the args (changing operation
1936      so value is preserved), for canonicalization.  Don't do this if
1937      the second arg is 0.  */
1938
1939   if (TREE_CONSTANT (primop0)
1940       && !integer_zerop (primop1) && !real_zerop (primop1))
1941     {
1942       tree tem = primop0;
1943       int temi = unsignedp0;
1944       primop0 = primop1;
1945       primop1 = tem;
1946       tem = op0;
1947       op0 = op1;
1948       op1 = tem;
1949       *op0_ptr = op0;
1950       *op1_ptr = op1;
1951       unsignedp0 = unsignedp1;
1952       unsignedp1 = temi;
1953       temi = real1;
1954       real1 = real2;
1955       real2 = temi;
1956
1957       switch (code)
1958         {
1959         case LT_EXPR:
1960           code = GT_EXPR;
1961           break;
1962         case GT_EXPR:
1963           code = LT_EXPR;
1964           break;
1965         case LE_EXPR:
1966           code = GE_EXPR;
1967           break;
1968         case GE_EXPR:
1969           code = LE_EXPR;
1970           break;
1971         default:
1972           break;
1973         }
1974       *rescode_ptr = code;
1975     }
1976
1977   /* If comparing an integer against a constant more bits wide,
1978      maybe we can deduce a value of 1 or 0 independent of the data.
1979      Or else truncate the constant now
1980      rather than extend the variable at run time.
1981
1982      This is only interesting if the constant is the wider arg.
1983      Also, it is not safe if the constant is unsigned and the
1984      variable arg is signed, since in this case the variable
1985      would be sign-extended and then regarded as unsigned.
1986      Our technique fails in this case because the lowest/highest
1987      possible unsigned results don't follow naturally from the
1988      lowest/highest possible values of the variable operand.
1989      For just EQ_EXPR and NE_EXPR there is another technique that
1990      could be used: see if the constant can be faithfully represented
1991      in the other operand's type, by truncating it and reextending it
1992      and see if that preserves the constant's value.  */
1993
1994   if (!real1 && !real2
1995       && TREE_CODE (primop1) == INTEGER_CST
1996       && TYPE_PRECISION (TREE_TYPE (primop0)) < TYPE_PRECISION (*restype_ptr))
1997     {
1998       int min_gt, max_gt, min_lt, max_lt;
1999       tree maxval, minval;
2000       /* 1 if comparison is nominally unsigned.  */
2001       int unsignedp = TYPE_UNSIGNED (*restype_ptr);
2002       tree val;
2003
2004       type = c_common_signed_or_unsigned_type (unsignedp0,
2005                                                TREE_TYPE (primop0));
2006
2007       maxval = TYPE_MAX_VALUE (type);
2008       minval = TYPE_MIN_VALUE (type);
2009
2010       if (unsignedp && !unsignedp0)
2011         *restype_ptr = c_common_signed_type (*restype_ptr);
2012
2013       if (TREE_TYPE (primop1) != *restype_ptr)
2014         {
2015           /* Convert primop1 to target type, but do not introduce
2016              additional overflow.  We know primop1 is an int_cst.  */
2017           tree tmp = build_int_cst_wide (*restype_ptr,
2018                                          TREE_INT_CST_LOW (primop1),
2019                                          TREE_INT_CST_HIGH (primop1));
2020
2021           primop1 = force_fit_type (tmp, 0, TREE_OVERFLOW (primop1),
2022                                     TREE_CONSTANT_OVERFLOW (primop1));
2023         }
2024       if (type != *restype_ptr)
2025         {
2026           minval = convert (*restype_ptr, minval);
2027           maxval = convert (*restype_ptr, maxval);
2028         }
2029
2030       if (unsignedp && unsignedp0)
2031         {
2032           min_gt = INT_CST_LT_UNSIGNED (primop1, minval);
2033           max_gt = INT_CST_LT_UNSIGNED (primop1, maxval);
2034           min_lt = INT_CST_LT_UNSIGNED (minval, primop1);
2035           max_lt = INT_CST_LT_UNSIGNED (maxval, primop1);
2036         }
2037       else
2038         {
2039           min_gt = INT_CST_LT (primop1, minval);
2040           max_gt = INT_CST_LT (primop1, maxval);
2041           min_lt = INT_CST_LT (minval, primop1);
2042           max_lt = INT_CST_LT (maxval, primop1);
2043         }
2044
2045       val = 0;
2046       /* This used to be a switch, but Genix compiler can't handle that.  */
2047       if (code == NE_EXPR)
2048         {
2049           if (max_lt || min_gt)
2050             val = truthvalue_true_node;
2051         }
2052       else if (code == EQ_EXPR)
2053         {
2054           if (max_lt || min_gt)
2055             val = truthvalue_false_node;
2056         }
2057       else if (code == LT_EXPR)
2058         {
2059           if (max_lt)
2060             val = truthvalue_true_node;
2061           if (!min_lt)
2062             val = truthvalue_false_node;
2063         }
2064       else if (code == GT_EXPR)
2065         {
2066           if (min_gt)
2067             val = truthvalue_true_node;
2068           if (!max_gt)
2069             val = truthvalue_false_node;
2070         }
2071       else if (code == LE_EXPR)
2072         {
2073           if (!max_gt)
2074             val = truthvalue_true_node;
2075           if (min_gt)
2076             val = truthvalue_false_node;
2077         }
2078       else if (code == GE_EXPR)
2079         {
2080           if (!min_lt)
2081             val = truthvalue_true_node;
2082           if (max_lt)
2083             val = truthvalue_false_node;
2084         }
2085
2086       /* If primop0 was sign-extended and unsigned comparison specd,
2087          we did a signed comparison above using the signed type bounds.
2088          But the comparison we output must be unsigned.
2089
2090          Also, for inequalities, VAL is no good; but if the signed
2091          comparison had *any* fixed result, it follows that the
2092          unsigned comparison just tests the sign in reverse
2093          (positive values are LE, negative ones GE).
2094          So we can generate an unsigned comparison
2095          against an extreme value of the signed type.  */
2096
2097       if (unsignedp && !unsignedp0)
2098         {
2099           if (val != 0)
2100             switch (code)
2101               {
2102               case LT_EXPR:
2103               case GE_EXPR:
2104                 primop1 = TYPE_MIN_VALUE (type);
2105                 val = 0;
2106                 break;
2107
2108               case LE_EXPR:
2109               case GT_EXPR:
2110                 primop1 = TYPE_MAX_VALUE (type);
2111                 val = 0;
2112                 break;
2113
2114               default:
2115                 break;
2116               }
2117           type = c_common_unsigned_type (type);
2118         }
2119
2120       if (TREE_CODE (primop0) != INTEGER_CST)
2121         {
2122           if (val == truthvalue_false_node)
2123             warning ("comparison is always false due to limited range of data type");
2124           if (val == truthvalue_true_node)
2125             warning ("comparison is always true due to limited range of data type");
2126         }
2127
2128       if (val != 0)
2129         {
2130           /* Don't forget to evaluate PRIMOP0 if it has side effects.  */
2131           if (TREE_SIDE_EFFECTS (primop0))
2132             return build2 (COMPOUND_EXPR, TREE_TYPE (val), primop0, val);
2133           return val;
2134         }
2135
2136       /* Value is not predetermined, but do the comparison
2137          in the type of the operand that is not constant.
2138          TYPE is already properly set.  */
2139     }
2140   else if (real1 && real2
2141            && (TYPE_PRECISION (TREE_TYPE (primop0))
2142                == TYPE_PRECISION (TREE_TYPE (primop1))))
2143     type = TREE_TYPE (primop0);
2144
2145   /* If args' natural types are both narrower than nominal type
2146      and both extend in the same manner, compare them
2147      in the type of the wider arg.
2148      Otherwise must actually extend both to the nominal
2149      common type lest different ways of extending
2150      alter the result.
2151      (eg, (short)-1 == (unsigned short)-1  should be 0.)  */
2152
2153   else if (unsignedp0 == unsignedp1 && real1 == real2
2154            && TYPE_PRECISION (TREE_TYPE (primop0)) < TYPE_PRECISION (*restype_ptr)
2155            && TYPE_PRECISION (TREE_TYPE (primop1)) < TYPE_PRECISION (*restype_ptr))
2156     {
2157       type = common_type (TREE_TYPE (primop0), TREE_TYPE (primop1));
2158       type = c_common_signed_or_unsigned_type (unsignedp0
2159                                                || TYPE_UNSIGNED (*restype_ptr),
2160                                                type);
2161       /* Make sure shorter operand is extended the right way
2162          to match the longer operand.  */
2163       primop0
2164         = convert (c_common_signed_or_unsigned_type (unsignedp0,
2165                                                      TREE_TYPE (primop0)),
2166                    primop0);
2167       primop1
2168         = convert (c_common_signed_or_unsigned_type (unsignedp1,
2169                                                      TREE_TYPE (primop1)),
2170                    primop1);
2171     }
2172   else
2173     {
2174       /* Here we must do the comparison on the nominal type
2175          using the args exactly as we received them.  */
2176       type = *restype_ptr;
2177       primop0 = op0;
2178       primop1 = op1;
2179
2180       if (!real1 && !real2 && integer_zerop (primop1)
2181           && TYPE_UNSIGNED (*restype_ptr))
2182         {
2183           tree value = 0;
2184           switch (code)
2185             {
2186             case GE_EXPR:
2187               /* All unsigned values are >= 0, so we warn if extra warnings
2188                  are requested.  However, if OP0 is a constant that is
2189                  >= 0, the signedness of the comparison isn't an issue,
2190                  so suppress the warning.  */
2191               if (extra_warnings && !in_system_header
2192                   && !(TREE_CODE (primop0) == INTEGER_CST
2193                        && !TREE_OVERFLOW (convert (c_common_signed_type (type),
2194                                                    primop0))))
2195                 warning ("comparison of unsigned expression >= 0 is always true");
2196               value = truthvalue_true_node;
2197               break;
2198
2199             case LT_EXPR:
2200               if (extra_warnings && !in_system_header
2201                   && !(TREE_CODE (primop0) == INTEGER_CST
2202                        && !TREE_OVERFLOW (convert (c_common_signed_type (type),
2203                                                    primop0))))
2204                 warning ("comparison of unsigned expression < 0 is always false");
2205               value = truthvalue_false_node;
2206               break;
2207
2208             default:
2209               break;
2210             }
2211
2212           if (value != 0)
2213             {
2214               /* Don't forget to evaluate PRIMOP0 if it has side effects.  */
2215               if (TREE_SIDE_EFFECTS (primop0))
2216                 return build2 (COMPOUND_EXPR, TREE_TYPE (value),
2217                                primop0, value);
2218               return value;
2219             }
2220         }
2221     }
2222
2223   *op0_ptr = convert (type, primop0);
2224   *op1_ptr = convert (type, primop1);
2225
2226   *restype_ptr = truthvalue_type_node;
2227
2228   return 0;
2229 }
2230 \f
2231 /* Return a tree for the sum or difference (RESULTCODE says which)
2232    of pointer PTROP and integer INTOP.  */
2233
2234 tree
2235 pointer_int_sum (enum tree_code resultcode, tree ptrop, tree intop)
2236 {
2237   tree size_exp;
2238
2239   /* The result is a pointer of the same type that is being added.  */
2240
2241   tree result_type = TREE_TYPE (ptrop);
2242
2243   if (TREE_CODE (TREE_TYPE (result_type)) == VOID_TYPE)
2244     {
2245       if (pedantic || warn_pointer_arith)
2246         pedwarn ("pointer of type %<void *%> used in arithmetic");
2247       size_exp = integer_one_node;
2248     }
2249   else if (TREE_CODE (TREE_TYPE (result_type)) == FUNCTION_TYPE)
2250     {
2251       if (pedantic || warn_pointer_arith)
2252         pedwarn ("pointer to a function used in arithmetic");
2253       size_exp = integer_one_node;
2254     }
2255   else if (TREE_CODE (TREE_TYPE (result_type)) == METHOD_TYPE)
2256     {
2257       if (pedantic || warn_pointer_arith)
2258         pedwarn ("pointer to member function used in arithmetic");
2259       size_exp = integer_one_node;
2260     }
2261   else
2262     size_exp = size_in_bytes (TREE_TYPE (result_type));
2263
2264   /* If what we are about to multiply by the size of the elements
2265      contains a constant term, apply distributive law
2266      and multiply that constant term separately.
2267      This helps produce common subexpressions.  */
2268
2269   if ((TREE_CODE (intop) == PLUS_EXPR || TREE_CODE (intop) == MINUS_EXPR)
2270       && !TREE_CONSTANT (intop)
2271       && TREE_CONSTANT (TREE_OPERAND (intop, 1))
2272       && TREE_CONSTANT (size_exp)
2273       /* If the constant comes from pointer subtraction,
2274          skip this optimization--it would cause an error.  */
2275       && TREE_CODE (TREE_TYPE (TREE_OPERAND (intop, 0))) == INTEGER_TYPE
2276       /* If the constant is unsigned, and smaller than the pointer size,
2277          then we must skip this optimization.  This is because it could cause
2278          an overflow error if the constant is negative but INTOP is not.  */
2279       && (!TYPE_UNSIGNED (TREE_TYPE (intop))
2280           || (TYPE_PRECISION (TREE_TYPE (intop))
2281               == TYPE_PRECISION (TREE_TYPE (ptrop)))))
2282     {
2283       enum tree_code subcode = resultcode;
2284       tree int_type = TREE_TYPE (intop);
2285       if (TREE_CODE (intop) == MINUS_EXPR)
2286         subcode = (subcode == PLUS_EXPR ? MINUS_EXPR : PLUS_EXPR);
2287       /* Convert both subexpression types to the type of intop,
2288          because weird cases involving pointer arithmetic
2289          can result in a sum or difference with different type args.  */
2290       ptrop = build_binary_op (subcode, ptrop,
2291                                convert (int_type, TREE_OPERAND (intop, 1)), 1);
2292       intop = convert (int_type, TREE_OPERAND (intop, 0));
2293     }
2294
2295   /* Convert the integer argument to a type the same size as sizetype
2296      so the multiply won't overflow spuriously.  */
2297
2298   if (TYPE_PRECISION (TREE_TYPE (intop)) != TYPE_PRECISION (sizetype)
2299       || TYPE_UNSIGNED (TREE_TYPE (intop)) != TYPE_UNSIGNED (sizetype))
2300     intop = convert (c_common_type_for_size (TYPE_PRECISION (sizetype),
2301                                              TYPE_UNSIGNED (sizetype)), intop);
2302
2303   /* Replace the integer argument with a suitable product by the object size.
2304      Do this multiplication as signed, then convert to the appropriate
2305      pointer type (actually unsigned integral).  */
2306
2307   intop = convert (result_type,
2308                    build_binary_op (MULT_EXPR, intop,
2309                                     convert (TREE_TYPE (intop), size_exp), 1));
2310
2311   /* Create the sum or difference.  */
2312   return fold (build2 (resultcode, result_type, ptrop, intop));
2313 }
2314 \f
2315 /* Prepare expr to be an argument of a TRUTH_NOT_EXPR,
2316    or for an `if' or `while' statement or ?..: exp.  It should already
2317    have been validated to be of suitable type; otherwise, a bad
2318    diagnostic may result.
2319
2320    This preparation consists of taking the ordinary
2321    representation of an expression expr and producing a valid tree
2322    boolean expression describing whether expr is nonzero.  We could
2323    simply always do build_binary_op (NE_EXPR, expr, truthvalue_false_node, 1),
2324    but we optimize comparisons, &&, ||, and !.
2325
2326    The resulting type should always be `truthvalue_type_node'.  */
2327
2328 tree
2329 c_common_truthvalue_conversion (tree expr)
2330 {
2331   switch (TREE_CODE (expr))
2332     {
2333     case EQ_EXPR:   case NE_EXPR:   case UNEQ_EXPR: case LTGT_EXPR:
2334     case LE_EXPR:   case GE_EXPR:   case LT_EXPR:   case GT_EXPR:
2335     case UNLE_EXPR: case UNGE_EXPR: case UNLT_EXPR: case UNGT_EXPR:
2336     case ORDERED_EXPR: case UNORDERED_EXPR:
2337       if (TREE_TYPE (expr) == truthvalue_type_node)
2338         return expr;
2339       return build2 (TREE_CODE (expr), truthvalue_type_node,
2340                      TREE_OPERAND (expr, 0), TREE_OPERAND (expr, 1));
2341
2342     case TRUTH_ANDIF_EXPR:
2343     case TRUTH_ORIF_EXPR:
2344     case TRUTH_AND_EXPR:
2345     case TRUTH_OR_EXPR:
2346     case TRUTH_XOR_EXPR:
2347       if (TREE_TYPE (expr) == truthvalue_type_node)
2348         return expr;
2349       return build2 (TREE_CODE (expr), truthvalue_type_node,
2350                  c_common_truthvalue_conversion (TREE_OPERAND (expr, 0)),
2351                  c_common_truthvalue_conversion (TREE_OPERAND (expr, 1)));
2352
2353     case TRUTH_NOT_EXPR:
2354       if (TREE_TYPE (expr) == truthvalue_type_node)
2355         return expr;
2356       return build1 (TREE_CODE (expr), truthvalue_type_node,
2357                  c_common_truthvalue_conversion (TREE_OPERAND (expr, 0)));
2358
2359     case ERROR_MARK:
2360       return expr;
2361
2362     case INTEGER_CST:
2363       /* Avoid integer_zerop to ignore TREE_CONSTANT_OVERFLOW.  */
2364       return (TREE_INT_CST_LOW (expr) != 0 || TREE_INT_CST_HIGH (expr) != 0)
2365              ? truthvalue_true_node
2366              : truthvalue_false_node;
2367
2368     case REAL_CST:
2369       return real_compare (NE_EXPR, &TREE_REAL_CST (expr), &dconst0)
2370              ? truthvalue_true_node
2371              : truthvalue_false_node;
2372
2373     case FUNCTION_DECL:
2374       expr = build_unary_op (ADDR_EXPR, expr, 0);
2375       /* Fall through.  */
2376
2377     case ADDR_EXPR:
2378       {
2379         if (TREE_CODE (TREE_OPERAND (expr, 0)) == FUNCTION_DECL
2380             && !DECL_WEAK (TREE_OPERAND (expr, 0)))
2381           {
2382             /* Common Ada/Pascal programmer's mistake.  We always warn
2383                about this since it is so bad.  */
2384             warning ("the address of %qD, will always evaluate as %<true%>",
2385                      TREE_OPERAND (expr, 0));
2386             return truthvalue_true_node;
2387           }
2388
2389         /* If we are taking the address of an external decl, it might be
2390            zero if it is weak, so we cannot optimize.  */
2391         if (DECL_P (TREE_OPERAND (expr, 0))
2392             && DECL_EXTERNAL (TREE_OPERAND (expr, 0)))
2393           break;
2394
2395         if (TREE_SIDE_EFFECTS (TREE_OPERAND (expr, 0)))
2396           return build2 (COMPOUND_EXPR, truthvalue_type_node,
2397                          TREE_OPERAND (expr, 0), truthvalue_true_node);
2398         else
2399           return truthvalue_true_node;
2400       }
2401
2402     case COMPLEX_EXPR:
2403       return build_binary_op ((TREE_SIDE_EFFECTS (TREE_OPERAND (expr, 1))
2404                                ? TRUTH_OR_EXPR : TRUTH_ORIF_EXPR),
2405                 c_common_truthvalue_conversion (TREE_OPERAND (expr, 0)),
2406                 c_common_truthvalue_conversion (TREE_OPERAND (expr, 1)),
2407                               0);
2408
2409     case NEGATE_EXPR:
2410     case ABS_EXPR:
2411     case FLOAT_EXPR:
2412       /* These don't change whether an object is nonzero or zero.  */
2413       return c_common_truthvalue_conversion (TREE_OPERAND (expr, 0));
2414
2415     case LROTATE_EXPR:
2416     case RROTATE_EXPR:
2417       /* These don't change whether an object is zero or nonzero, but
2418          we can't ignore them if their second arg has side-effects.  */
2419       if (TREE_SIDE_EFFECTS (TREE_OPERAND (expr, 1)))
2420         return build2 (COMPOUND_EXPR, truthvalue_type_node,
2421                        TREE_OPERAND (expr, 1),
2422                        c_common_truthvalue_conversion (TREE_OPERAND (expr, 0)));
2423       else
2424         return c_common_truthvalue_conversion (TREE_OPERAND (expr, 0));
2425
2426     case COND_EXPR:
2427       /* Distribute the conversion into the arms of a COND_EXPR.  */
2428       return fold (build3 (COND_EXPR, truthvalue_type_node,
2429                 TREE_OPERAND (expr, 0),
2430                 c_common_truthvalue_conversion (TREE_OPERAND (expr, 1)),
2431                 c_common_truthvalue_conversion (TREE_OPERAND (expr, 2))));
2432
2433     case CONVERT_EXPR:
2434       /* Don't cancel the effect of a CONVERT_EXPR from a REFERENCE_TYPE,
2435          since that affects how `default_conversion' will behave.  */
2436       if (TREE_CODE (TREE_TYPE (expr)) == REFERENCE_TYPE
2437           || TREE_CODE (TREE_TYPE (TREE_OPERAND (expr, 0))) == REFERENCE_TYPE)
2438         break;
2439       /* Fall through....  */
2440     case NOP_EXPR:
2441       /* If this is widening the argument, we can ignore it.  */
2442       if (TYPE_PRECISION (TREE_TYPE (expr))
2443           >= TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (expr, 0))))
2444         return c_common_truthvalue_conversion (TREE_OPERAND (expr, 0));
2445       break;
2446
2447     case MINUS_EXPR:
2448       /* Perhaps reduce (x - y) != 0 to (x != y).  The expressions
2449          aren't guaranteed to the be same for modes that can represent
2450          infinity, since if x and y are both +infinity, or both
2451          -infinity, then x - y is not a number.
2452
2453          Note that this transformation is safe when x or y is NaN.
2454          (x - y) is then NaN, and both (x - y) != 0 and x != y will
2455          be false.  */
2456       if (HONOR_INFINITIES (TYPE_MODE (TREE_TYPE (TREE_OPERAND (expr, 0)))))
2457         break;
2458       /* Fall through....  */
2459     case BIT_XOR_EXPR:
2460       /* This and MINUS_EXPR can be changed into a comparison of the
2461          two objects.  */
2462       if (TREE_TYPE (TREE_OPERAND (expr, 0))
2463           == TREE_TYPE (TREE_OPERAND (expr, 1)))
2464         return build_binary_op (NE_EXPR, TREE_OPERAND (expr, 0),
2465                                 TREE_OPERAND (expr, 1), 1);
2466       return build_binary_op (NE_EXPR, TREE_OPERAND (expr, 0),
2467                               fold (build1 (NOP_EXPR,
2468                                             TREE_TYPE (TREE_OPERAND (expr, 0)),
2469                                             TREE_OPERAND (expr, 1))), 1);
2470
2471     case BIT_AND_EXPR:
2472       if (integer_onep (TREE_OPERAND (expr, 1))
2473           && TREE_TYPE (expr) != truthvalue_type_node)
2474         /* Using convert here would cause infinite recursion.  */
2475         return build1 (NOP_EXPR, truthvalue_type_node, expr);
2476       break;
2477
2478     case MODIFY_EXPR:
2479       if (warn_parentheses && !TREE_NO_WARNING (expr))
2480         warning ("suggest parentheses around assignment used as truth value");
2481       break;
2482
2483     default:
2484       break;
2485     }
2486
2487   if (TREE_CODE (TREE_TYPE (expr)) == COMPLEX_TYPE)
2488     {
2489       tree t = save_expr (expr);
2490       return (build_binary_op
2491               ((TREE_SIDE_EFFECTS (expr)
2492                 ? TRUTH_OR_EXPR : TRUTH_ORIF_EXPR),
2493         c_common_truthvalue_conversion (build_unary_op (REALPART_EXPR, t, 0)),
2494         c_common_truthvalue_conversion (build_unary_op (IMAGPART_EXPR, t, 0)),
2495                0));
2496     }
2497
2498   return build_binary_op (NE_EXPR, expr, integer_zero_node, 1);
2499 }
2500 \f
2501 static tree builtin_function_2 (const char *builtin_name, const char *name,
2502                                 tree builtin_type, tree type,
2503                                 enum built_in_function function_code,
2504                                 enum built_in_class cl, int library_name_p,
2505                                 bool nonansi_p,
2506                                 tree attrs);
2507
2508 /* Make a variant type in the proper way for C/C++, propagating qualifiers
2509    down to the element type of an array.  */
2510
2511 tree
2512 c_build_qualified_type (tree type, int type_quals)
2513 {
2514   if (type == error_mark_node)
2515     return type;
2516
2517   if (TREE_CODE (type) == ARRAY_TYPE)
2518     {
2519       tree t;
2520       tree element_type = c_build_qualified_type (TREE_TYPE (type),
2521                                                   type_quals);
2522
2523       /* See if we already have an identically qualified type.  */
2524       for (t = TYPE_MAIN_VARIANT (type); t; t = TYPE_NEXT_VARIANT (t))
2525         {
2526           if (TYPE_QUALS (strip_array_types (t)) == type_quals
2527               && TYPE_NAME (t) == TYPE_NAME (type)
2528               && TYPE_CONTEXT (t) == TYPE_CONTEXT (type)
2529               && attribute_list_equal (TYPE_ATTRIBUTES (t),
2530                                        TYPE_ATTRIBUTES (type)))
2531             break;
2532         }
2533       if (!t)
2534         {
2535           t = build_variant_type_copy (type);
2536           TREE_TYPE (t) = element_type;
2537         }
2538       return t;
2539     }
2540
2541   /* A restrict-qualified pointer type must be a pointer to object or
2542      incomplete type.  Note that the use of POINTER_TYPE_P also allows
2543      REFERENCE_TYPEs, which is appropriate for C++.  */
2544   if ((type_quals & TYPE_QUAL_RESTRICT)
2545       && (!POINTER_TYPE_P (type)
2546           || !C_TYPE_OBJECT_OR_INCOMPLETE_P (TREE_TYPE (type))))
2547     {
2548       error ("invalid use of %<restrict%>");
2549       type_quals &= ~TYPE_QUAL_RESTRICT;
2550     }
2551
2552   return build_qualified_type (type, type_quals);
2553 }
2554
2555 /* Apply the TYPE_QUALS to the new DECL.  */
2556
2557 void
2558 c_apply_type_quals_to_decl (int type_quals, tree decl)
2559 {
2560   tree type = TREE_TYPE (decl);
2561
2562   if (type == error_mark_node)
2563     return;
2564
2565   if (((type_quals & TYPE_QUAL_CONST)
2566        || (type && TREE_CODE (type) == REFERENCE_TYPE))
2567       /* An object declared 'const' is only readonly after it is
2568          initialized.  We don't have any way of expressing this currently,
2569          so we need to be conservative and unset TREE_READONLY for types
2570          with constructors.  Otherwise aliasing code will ignore stores in
2571          an inline constructor.  */
2572       && !(type && TYPE_NEEDS_CONSTRUCTING (type)))
2573     TREE_READONLY (decl) = 1;
2574   if (type_quals & TYPE_QUAL_VOLATILE)
2575     {
2576       TREE_SIDE_EFFECTS (decl) = 1;
2577       TREE_THIS_VOLATILE (decl) = 1;
2578     }
2579   if (type_quals & TYPE_QUAL_RESTRICT)
2580     {
2581       while (type && TREE_CODE (type) == ARRAY_TYPE)
2582         /* Allow 'restrict' on arrays of pointers.
2583            FIXME currently we just ignore it.  */
2584         type = TREE_TYPE (type);
2585       if (!type
2586           || !POINTER_TYPE_P (type)
2587           || !C_TYPE_OBJECT_OR_INCOMPLETE_P (TREE_TYPE (type)))
2588         error ("invalid use of %<restrict%>");
2589       else if (flag_strict_aliasing && type == TREE_TYPE (decl))
2590         /* Indicate we need to make a unique alias set for this pointer.
2591            We can't do it here because it might be pointing to an
2592            incomplete type.  */
2593         DECL_POINTER_ALIAS_SET (decl) = -2;
2594     }
2595 }
2596
2597 /* Hash function for the problem of multiple type definitions in
2598    different files.  This must hash all types that will compare
2599    equal via comptypes to the same value.  In practice it hashes
2600    on some of the simple stuff and leaves the details to comptypes.  */
2601
2602 static hashval_t
2603 c_type_hash (const void *p)
2604 {
2605   int i = 0;
2606   int shift, size;
2607   tree t = (tree) p;
2608   tree t2;
2609   switch (TREE_CODE (t))
2610     {
2611     /* For pointers, hash on pointee type plus some swizzling.  */
2612     case POINTER_TYPE:
2613       return c_type_hash (TREE_TYPE (t)) ^ 0x3003003;
2614     /* Hash on number of elements and total size.  */
2615     case ENUMERAL_TYPE:
2616       shift = 3;
2617       t2 = TYPE_VALUES (t);
2618       break;
2619     case RECORD_TYPE:
2620       shift = 0;
2621       t2 = TYPE_FIELDS (t);
2622       break;
2623     case QUAL_UNION_TYPE:
2624       shift = 1;
2625       t2 = TYPE_FIELDS (t);
2626       break;
2627     case UNION_TYPE:
2628       shift = 2;
2629       t2 = TYPE_FIELDS (t);
2630       break;
2631     default:
2632       gcc_unreachable ();
2633     }
2634   for (; t2; t2 = TREE_CHAIN (t2))
2635     i++;
2636   size = TREE_INT_CST_LOW (TYPE_SIZE (t));
2637   return ((size << 24) | (i << shift));
2638 }
2639
2640 static GTY((param_is (union tree_node))) htab_t type_hash_table;
2641
2642 /* Return the typed-based alias set for T, which may be an expression
2643    or a type.  Return -1 if we don't do anything special.  */
2644
2645 HOST_WIDE_INT
2646 c_common_get_alias_set (tree t)
2647 {
2648   tree u;
2649   PTR *slot;
2650
2651   /* Permit type-punning when accessing a union, provided the access
2652      is directly through the union.  For example, this code does not
2653      permit taking the address of a union member and then storing
2654      through it.  Even the type-punning allowed here is a GCC
2655      extension, albeit a common and useful one; the C standard says
2656      that such accesses have implementation-defined behavior.  */
2657   for (u = t;
2658        TREE_CODE (u) == COMPONENT_REF || TREE_CODE (u) == ARRAY_REF;
2659        u = TREE_OPERAND (u, 0))
2660     if (TREE_CODE (u) == COMPONENT_REF
2661         && TREE_CODE (TREE_TYPE (TREE_OPERAND (u, 0))) == UNION_TYPE)
2662       return 0;
2663
2664   /* That's all the expressions we handle specially.  */
2665   if (!TYPE_P (t))
2666     return -1;
2667
2668   /* The C standard guarantees that any object may be accessed via an
2669      lvalue that has character type.  */
2670   if (t == char_type_node
2671       || t == signed_char_type_node
2672       || t == unsigned_char_type_node)
2673     return 0;
2674
2675   /* If it has the may_alias attribute, it can alias anything.  */
2676   if (lookup_attribute ("may_alias", TYPE_ATTRIBUTES (t)))
2677     return 0;
2678
2679   /* The C standard specifically allows aliasing between signed and
2680      unsigned variants of the same type.  We treat the signed
2681      variant as canonical.  */
2682   if (TREE_CODE (t) == INTEGER_TYPE && TYPE_UNSIGNED (t))
2683     {
2684       tree t1 = c_common_signed_type (t);
2685
2686       /* t1 == t can happen for boolean nodes which are always unsigned.  */
2687       if (t1 != t)
2688         return get_alias_set (t1);
2689     }
2690   else if (POINTER_TYPE_P (t))
2691     {
2692       tree t1;
2693
2694       /* Unfortunately, there is no canonical form of a pointer type.
2695          In particular, if we have `typedef int I', then `int *', and
2696          `I *' are different types.  So, we have to pick a canonical
2697          representative.  We do this below.
2698
2699          Technically, this approach is actually more conservative that
2700          it needs to be.  In particular, `const int *' and `int *'
2701          should be in different alias sets, according to the C and C++
2702          standard, since their types are not the same, and so,
2703          technically, an `int **' and `const int **' cannot point at
2704          the same thing.
2705
2706          But, the standard is wrong.  In particular, this code is
2707          legal C++:
2708
2709             int *ip;
2710             int **ipp = &ip;
2711             const int* const* cipp = ipp;
2712
2713          And, it doesn't make sense for that to be legal unless you
2714          can dereference IPP and CIPP.  So, we ignore cv-qualifiers on
2715          the pointed-to types.  This issue has been reported to the
2716          C++ committee.  */
2717       t1 = build_type_no_quals (t);
2718       if (t1 != t)
2719         return get_alias_set (t1);
2720     }
2721
2722   /* Handle the case of multiple type nodes referring to "the same" type,
2723      which occurs with IMA.  These share an alias set.  FIXME:  Currently only
2724      C90 is handled.  (In C99 type compatibility is not transitive, which
2725      complicates things mightily. The alias set splay trees can theoretically
2726      represent this, but insertion is tricky when you consider all the
2727      different orders things might arrive in.) */
2728
2729   if (c_language != clk_c || flag_isoc99)
2730     return -1;
2731
2732   /* Save time if there's only one input file.  */
2733   if (num_in_fnames == 1)
2734     return -1;
2735
2736   /* Pointers need special handling if they point to any type that
2737      needs special handling (below).  */
2738   if (TREE_CODE (t) == POINTER_TYPE)
2739     {
2740       tree t2;
2741       /* Find bottom type under any nested POINTERs.  */
2742       for (t2 = TREE_TYPE (t);
2743      TREE_CODE (t2) == POINTER_TYPE;
2744      t2 = TREE_TYPE (t2))
2745   ;
2746       if (TREE_CODE (t2) != RECORD_TYPE
2747     && TREE_CODE (t2) != ENUMERAL_TYPE
2748     && TREE_CODE (t2) != QUAL_UNION_TYPE
2749     && TREE_CODE (t2) != UNION_TYPE)
2750   return -1;
2751       if (TYPE_SIZE (t2) == 0)
2752   return -1;
2753     }
2754   /* These are the only cases that need special handling.  */
2755   if (TREE_CODE (t) != RECORD_TYPE
2756       && TREE_CODE (t) != ENUMERAL_TYPE
2757       && TREE_CODE (t) != QUAL_UNION_TYPE
2758       && TREE_CODE (t) != UNION_TYPE
2759       && TREE_CODE (t) != POINTER_TYPE)
2760     return -1;
2761   /* Undefined? */
2762   if (TYPE_SIZE (t) == 0)
2763     return -1;
2764
2765   /* Look up t in hash table.  Only one of the compatible types within each
2766      alias set is recorded in the table.  */
2767   if (!type_hash_table)
2768     type_hash_table = htab_create_ggc (1021, c_type_hash,
2769             (htab_eq) lang_hooks.types_compatible_p,
2770             NULL);
2771   slot = htab_find_slot (type_hash_table, t, INSERT);
2772   if (*slot != NULL)
2773     {
2774       TYPE_ALIAS_SET (t) = TYPE_ALIAS_SET ((tree)*slot);
2775       return TYPE_ALIAS_SET ((tree)*slot);
2776     }
2777   else
2778     /* Our caller will assign and record (in t) a new alias set; all we need
2779        to do is remember t in the hash table.  */
2780     *slot = t;
2781
2782   return -1;
2783 }
2784 \f
2785 /* Compute the value of 'sizeof (TYPE)' or '__alignof__ (TYPE)', where the
2786    second parameter indicates which OPERATOR is being applied.  The COMPLAIN
2787    flag controls whether we should diagnose possibly ill-formed
2788    constructs or not.  */
2789
2790 tree
2791 c_sizeof_or_alignof_type (tree type, bool is_sizeof, int complain)
2792 {
2793   const char *op_name;
2794   tree value = NULL;
2795   enum tree_code type_code = TREE_CODE (type);
2796
2797   op_name = is_sizeof ? "sizeof" : "__alignof__";
2798
2799   if (type_code == FUNCTION_TYPE)
2800     {
2801       if (is_sizeof)
2802         {
2803           if (complain && (pedantic || warn_pointer_arith))
2804             pedwarn ("invalid application of %<sizeof%> to a function type");
2805           value = size_one_node;
2806         }
2807       else
2808         value = size_int (FUNCTION_BOUNDARY / BITS_PER_UNIT);
2809     }
2810   else if (type_code == VOID_TYPE || type_code == ERROR_MARK)
2811     {
2812       if (type_code == VOID_TYPE
2813           && complain && (pedantic || warn_pointer_arith))
2814         pedwarn ("invalid application of %qs to a void type", op_name);
2815       value = size_one_node;
2816     }
2817   else if (!COMPLETE_TYPE_P (type))
2818     {
2819       if (complain)
2820         error ("invalid application of %qs to incomplete type %qT ",
2821                op_name, type);
2822       value = size_zero_node;
2823     }
2824   else
2825     {
2826       if (is_sizeof)
2827         /* Convert in case a char is more than one unit.  */
2828         value = size_binop (CEIL_DIV_EXPR, TYPE_SIZE_UNIT (type),
2829                             size_int (TYPE_PRECISION (char_type_node)
2830                                       / BITS_PER_UNIT));
2831       else
2832         value = size_int (TYPE_ALIGN_UNIT (type));
2833     }
2834
2835   /* VALUE will have an integer type with TYPE_IS_SIZETYPE set.
2836      TYPE_IS_SIZETYPE means that certain things (like overflow) will
2837      never happen.  However, this node should really have type
2838      `size_t', which is just a typedef for an ordinary integer type.  */
2839   value = fold (build1 (NOP_EXPR, size_type_node, value));
2840   gcc_assert (!TYPE_IS_SIZETYPE (TREE_TYPE (value)));
2841
2842   return value;
2843 }
2844
2845 /* Implement the __alignof keyword: Return the minimum required
2846    alignment of EXPR, measured in bytes.  For VAR_DECL's and
2847    FIELD_DECL's return DECL_ALIGN (which can be set from an
2848    "aligned" __attribute__ specification).  */
2849
2850 tree
2851 c_alignof_expr (tree expr)
2852 {
2853   tree t;
2854
2855   if (TREE_CODE (expr) == VAR_DECL)
2856     t = size_int (DECL_ALIGN_UNIT (expr));
2857
2858   else if (TREE_CODE (expr) == COMPONENT_REF
2859            && DECL_C_BIT_FIELD (TREE_OPERAND (expr, 1)))
2860     {
2861       error ("%<__alignof%> applied to a bit-field");
2862       t = size_one_node;
2863     }
2864   else if (TREE_CODE (expr) == COMPONENT_REF
2865            && TREE_CODE (TREE_OPERAND (expr, 1)) == FIELD_DECL)
2866     t = size_int (DECL_ALIGN_UNIT (TREE_OPERAND (expr, 1)));
2867
2868   else if (TREE_CODE (expr) == INDIRECT_REF)
2869     {
2870       tree t = TREE_OPERAND (expr, 0);
2871       tree best = t;
2872       int bestalign = TYPE_ALIGN (TREE_TYPE (TREE_TYPE (t)));
2873
2874       while (TREE_CODE (t) == NOP_EXPR
2875              && TREE_CODE (TREE_TYPE (TREE_OPERAND (t, 0))) == POINTER_TYPE)
2876         {
2877           int thisalign;
2878
2879           t = TREE_OPERAND (t, 0);
2880           thisalign = TYPE_ALIGN (TREE_TYPE (TREE_TYPE (t)));
2881           if (thisalign > bestalign)
2882             best = t, bestalign = thisalign;
2883         }
2884       return c_alignof (TREE_TYPE (TREE_TYPE (best)));
2885     }
2886   else
2887     return c_alignof (TREE_TYPE (expr));
2888
2889   return fold (build1 (NOP_EXPR, size_type_node, t));
2890 }
2891 \f
2892 /* Handle C and C++ default attributes.  */
2893
2894 enum built_in_attribute
2895 {
2896 #define DEF_ATTR_NULL_TREE(ENUM) ENUM,
2897 #define DEF_ATTR_INT(ENUM, VALUE) ENUM,
2898 #define DEF_ATTR_IDENT(ENUM, STRING) ENUM,
2899 #define DEF_ATTR_TREE_LIST(ENUM, PURPOSE, VALUE, CHAIN) ENUM,
2900 #include "builtin-attrs.def"
2901 #undef DEF_ATTR_NULL_TREE
2902 #undef DEF_ATTR_INT
2903 #undef DEF_ATTR_IDENT
2904 #undef DEF_ATTR_TREE_LIST
2905   ATTR_LAST
2906 };
2907
2908 static GTY(()) tree built_in_attributes[(int) ATTR_LAST];
2909
2910 static void c_init_attributes (void);
2911
2912 /* Build tree nodes and builtin functions common to both C and C++ language
2913    frontends.  */
2914
2915 void
2916 c_common_nodes_and_builtins (void)
2917 {
2918   enum builtin_type
2919   {
2920 #define DEF_PRIMITIVE_TYPE(NAME, VALUE) NAME,
2921 #define DEF_FUNCTION_TYPE_0(NAME, RETURN) NAME,
2922 #define DEF_FUNCTION_TYPE_1(NAME, RETURN, ARG1) NAME,
2923 #define DEF_FUNCTION_TYPE_2(NAME, RETURN, ARG1, ARG2) NAME,
2924 #define DEF_FUNCTION_TYPE_3(NAME, RETURN, ARG1, ARG2, ARG3) NAME,
2925 #define DEF_FUNCTION_TYPE_4(NAME, RETURN, ARG1, ARG2, ARG3, ARG4) NAME,
2926 #define DEF_FUNCTION_TYPE_VAR_0(NAME, RETURN) NAME,
2927 #define DEF_FUNCTION_TYPE_VAR_1(NAME, RETURN, ARG1) NAME,
2928 #define DEF_FUNCTION_TYPE_VAR_2(NAME, RETURN, ARG1, ARG2) NAME,
2929 #define DEF_FUNCTION_TYPE_VAR_3(NAME, RETURN, ARG1, ARG2, ARG3) NAME,
2930 #define DEF_POINTER_TYPE(NAME, TYPE) NAME,
2931 #include "builtin-types.def"
2932 #undef DEF_PRIMITIVE_TYPE
2933 #undef DEF_FUNCTION_TYPE_0
2934 #undef DEF_FUNCTION_TYPE_1
2935 #undef DEF_FUNCTION_TYPE_2
2936 #undef DEF_FUNCTION_TYPE_3
2937 #undef DEF_FUNCTION_TYPE_4
2938 #undef DEF_FUNCTION_TYPE_VAR_0
2939 #undef DEF_FUNCTION_TYPE_VAR_1
2940 #undef DEF_FUNCTION_TYPE_VAR_2
2941 #undef DEF_FUNCTION_TYPE_VAR_3
2942 #undef DEF_POINTER_TYPE
2943     BT_LAST
2944   };
2945
2946   typedef enum builtin_type builtin_type;
2947
2948   tree builtin_types[(int) BT_LAST];
2949   int wchar_type_size;
2950   tree array_domain_type;
2951   tree va_list_ref_type_node;
2952   tree va_list_arg_type_node;
2953
2954   /* Define `int' and `char' first so that dbx will output them first.  */
2955   record_builtin_type (RID_INT, NULL, integer_type_node);
2956   record_builtin_type (RID_CHAR, "char", char_type_node);
2957
2958   /* `signed' is the same as `int'.  FIXME: the declarations of "signed",
2959      "unsigned long", "long long unsigned" and "unsigned short" were in C++
2960      but not C.  Are the conditionals here needed?  */
2961   if (c_dialect_cxx ())
2962     record_builtin_type (RID_SIGNED, NULL, integer_type_node);
2963   record_builtin_type (RID_LONG, "long int", long_integer_type_node);
2964   record_builtin_type (RID_UNSIGNED, "unsigned int", unsigned_type_node);
2965   record_builtin_type (RID_MAX, "long unsigned int",
2966                        long_unsigned_type_node);
2967   if (c_dialect_cxx ())
2968     record_builtin_type (RID_MAX, "unsigned long", long_unsigned_type_node);
2969   record_builtin_type (RID_MAX, "long long int",
2970                        long_long_integer_type_node);
2971   record_builtin_type (RID_MAX, "long long unsigned int",
2972                        long_long_unsigned_type_node);
2973   if (c_dialect_cxx ())
2974     record_builtin_type (RID_MAX, "long long unsigned",
2975                          long_long_unsigned_type_node);
2976   record_builtin_type (RID_SHORT, "short int", short_integer_type_node);
2977   record_builtin_type (RID_MAX, "short unsigned int",
2978                        short_unsigned_type_node);
2979   if (c_dialect_cxx ())
2980     record_builtin_type (RID_MAX, "unsigned short",
2981                          short_unsigned_type_node);
2982
2983   /* Define both `signed char' and `unsigned char'.  */
2984   record_builtin_type (RID_MAX, "signed char", signed_char_type_node);
2985   record_builtin_type (RID_MAX, "unsigned char", unsigned_char_type_node);
2986
2987   /* These are types that c_common_type_for_size and
2988      c_common_type_for_mode use.  */
2989   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
2990                                          intQI_type_node));
2991   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
2992                                          intHI_type_node));
2993   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
2994                                          intSI_type_node));
2995   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
2996                                          intDI_type_node));
2997 #if HOST_BITS_PER_WIDE_INT >= 64
2998   if (targetm.scalar_mode_supported_p (TImode))
2999     lang_hooks.decls.pushdecl (build_decl (TYPE_DECL,
3000                                            get_identifier ("__int128_t"),
3001                                            intTI_type_node));
3002 #endif
3003   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
3004                                          unsigned_intQI_type_node));
3005   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
3006                                          unsigned_intHI_type_node));
3007   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
3008                                          unsigned_intSI_type_node));
3009   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
3010                                          unsigned_intDI_type_node));
3011 #if HOST_BITS_PER_WIDE_INT >= 64
3012   if (targetm.scalar_mode_supported_p (TImode))
3013     lang_hooks.decls.pushdecl (build_decl (TYPE_DECL,
3014                                            get_identifier ("__uint128_t"),
3015                                            unsigned_intTI_type_node));
3016 #endif
3017
3018   /* Create the widest literal types.  */
3019   widest_integer_literal_type_node
3020     = make_signed_type (HOST_BITS_PER_WIDE_INT * 2);
3021   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
3022                                          widest_integer_literal_type_node));
3023
3024   widest_unsigned_literal_type_node
3025     = make_unsigned_type (HOST_BITS_PER_WIDE_INT * 2);
3026   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
3027                                          widest_unsigned_literal_type_node));
3028
3029   /* `unsigned long' is the standard type for sizeof.
3030      Note that stddef.h uses `unsigned long',
3031      and this must agree, even if long and int are the same size.  */
3032   size_type_node =
3033     TREE_TYPE (identifier_global_value (get_identifier (SIZE_TYPE)));
3034   signed_size_type_node = c_common_signed_type (size_type_node);
3035   set_sizetype (size_type_node);
3036
3037   pid_type_node =
3038     TREE_TYPE (identifier_global_value (get_identifier (PID_TYPE)));
3039
3040   build_common_tree_nodes_2 (flag_short_double);
3041
3042   record_builtin_type (RID_FLOAT, NULL, float_type_node);
3043   record_builtin_type (RID_DOUBLE, NULL, double_type_node);
3044   record_builtin_type (RID_MAX, "long double", long_double_type_node);
3045
3046   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL,
3047                                          get_identifier ("complex int"),
3048                                          complex_integer_type_node));
3049   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL,
3050                                          get_identifier ("complex float"),
3051                                          complex_float_type_node));
3052   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL,
3053                                          get_identifier ("complex double"),
3054                                          complex_double_type_node));
3055   lang_hooks.decls.pushdecl
3056     (build_decl (TYPE_DECL, get_identifier ("complex long double"),
3057                  complex_long_double_type_node));
3058
3059   if (c_dialect_cxx ())
3060     /* For C++, make fileptr_type_node a distinct void * type until
3061        FILE type is defined.  */
3062     fileptr_type_node = build_variant_type_copy (ptr_type_node);
3063
3064   record_builtin_type (RID_VOID, NULL, void_type_node);
3065
3066   /* This node must not be shared.  */
3067   void_zero_node = make_node (INTEGER_CST);
3068   TREE_TYPE (void_zero_node) = void_type_node;
3069
3070   void_list_node = build_void_list_node ();
3071
3072   /* Make a type to be the domain of a few array types
3073      whose domains don't really matter.
3074      200 is small enough that it always fits in size_t
3075      and large enough that it can hold most function names for the
3076      initializations of __FUNCTION__ and __PRETTY_FUNCTION__.  */
3077   array_domain_type = build_index_type (size_int (200));
3078
3079   /* Make a type for arrays of characters.
3080      With luck nothing will ever really depend on the length of this
3081      array type.  */
3082   char_array_type_node
3083     = build_array_type (char_type_node, array_domain_type);
3084
3085   /* Likewise for arrays of ints.  */
3086   int_array_type_node
3087     = build_array_type (integer_type_node, array_domain_type);
3088
3089   string_type_node = build_pointer_type (char_type_node);
3090   const_string_type_node
3091     = build_pointer_type (build_qualified_type
3092                           (char_type_node, TYPE_QUAL_CONST));
3093
3094   /* This is special for C++ so functions can be overloaded.  */
3095   wchar_type_node = get_identifier (MODIFIED_WCHAR_TYPE);
3096   wchar_type_node = TREE_TYPE (identifier_global_value (wchar_type_node));
3097   wchar_type_size = TYPE_PRECISION (wchar_type_node);
3098   if (c_dialect_cxx ())
3099     {
3100       if (TYPE_UNSIGNED (wchar_type_node))
3101         wchar_type_node = make_unsigned_type (wchar_type_size);
3102       else
3103         wchar_type_node = make_signed_type (wchar_type_size);
3104       record_builtin_type (RID_WCHAR, "wchar_t", wchar_type_node);
3105     }
3106   else
3107     {
3108       signed_wchar_type_node = c_common_signed_type (wchar_type_node);
3109       unsigned_wchar_type_node = c_common_unsigned_type (wchar_type_node);
3110     }
3111
3112   /* This is for wide string constants.  */
3113   wchar_array_type_node
3114     = build_array_type (wchar_type_node, array_domain_type);
3115
3116   wint_type_node =
3117     TREE_TYPE (identifier_global_value (get_identifier (WINT_TYPE)));
3118
3119   intmax_type_node =
3120     TREE_TYPE (identifier_global_value (get_identifier (INTMAX_TYPE)));
3121   uintmax_type_node =
3122     TREE_TYPE (identifier_global_value (get_identifier (UINTMAX_TYPE)));
3123
3124   default_function_type = build_function_type (integer_type_node, NULL_TREE);
3125   ptrdiff_type_node
3126     = TREE_TYPE (identifier_global_value (get_identifier (PTRDIFF_TYPE)));
3127   unsigned_ptrdiff_type_node = c_common_unsigned_type (ptrdiff_type_node);
3128
3129   lang_hooks.decls.pushdecl
3130     (build_decl (TYPE_DECL, get_identifier ("__builtin_va_list"),
3131                  va_list_type_node));
3132
3133   if (TREE_CODE (va_list_type_node) == ARRAY_TYPE)
3134     {
3135       va_list_arg_type_node = va_list_ref_type_node =
3136         build_pointer_type (TREE_TYPE (va_list_type_node));
3137     }
3138   else
3139     {
3140       va_list_arg_type_node = va_list_type_node;
3141       va_list_ref_type_node = build_reference_type (va_list_type_node);
3142     }
3143
3144 #define DEF_PRIMITIVE_TYPE(ENUM, VALUE) \
3145   builtin_types[(int) ENUM] = VALUE;
3146 #define DEF_FUNCTION_TYPE_0(ENUM, RETURN)               \
3147   builtin_types[(int) ENUM]                             \
3148     = build_function_type (builtin_types[(int) RETURN], \
3149                            void_list_node);
3150 #define DEF_FUNCTION_TYPE_1(ENUM, RETURN, ARG1)                         \
3151   builtin_types[(int) ENUM]                                             \
3152     = build_function_type (builtin_types[(int) RETURN],                 \
3153                            tree_cons (NULL_TREE,                        \
3154                                       builtin_types[(int) ARG1],        \
3155                                       void_list_node));
3156 #define DEF_FUNCTION_TYPE_2(ENUM, RETURN, ARG1, ARG2)   \
3157   builtin_types[(int) ENUM]                             \
3158     = build_function_type                               \
3159       (builtin_types[(int) RETURN],                     \
3160        tree_cons (NULL_TREE,                            \
3161                   builtin_types[(int) ARG1],            \
3162                   tree_cons (NULL_TREE,                 \
3163                              builtin_types[(int) ARG2], \
3164                              void_list_node)));
3165 #define DEF_FUNCTION_TYPE_3(ENUM, RETURN, ARG1, ARG2, ARG3)              \
3166   builtin_types[(int) ENUM]                                              \
3167     = build_function_type                                                \
3168       (builtin_types[(int) RETURN],                                      \
3169        tree_cons (NULL_TREE,                                             \
3170                   builtin_types[(int) ARG1],                             \
3171                   tree_cons (NULL_TREE,                                  \
3172                              builtin_types[(int) ARG2],                  \
3173                              tree_cons (NULL_TREE,                       \
3174                                         builtin_types[(int) ARG3],       \
3175                                         void_list_node))));
3176 #define DEF_FUNCTION_TYPE_4(ENUM, RETURN, ARG1, ARG2, ARG3, ARG4)       \
3177   builtin_types[(int) ENUM]                                             \
3178     = build_function_type                                               \
3179       (builtin_types[(int) RETURN],                                     \
3180        tree_cons (NULL_TREE,                                            \
3181                   builtin_types[(int) ARG1],                            \
3182                   tree_cons (NULL_TREE,                                 \
3183                              builtin_types[(int) ARG2],                 \
3184                              tree_cons                                  \
3185                              (NULL_TREE,                                \
3186                               builtin_types[(int) ARG3],                \
3187                               tree_cons (NULL_TREE,                     \
3188                                          builtin_types[(int) ARG4],     \
3189                                          void_list_node)))));
3190 #define DEF_FUNCTION_TYPE_VAR_0(ENUM, RETURN)                           \
3191   builtin_types[(int) ENUM]                                             \
3192     = build_function_type (builtin_types[(int) RETURN], NULL_TREE);
3193 #define DEF_FUNCTION_TYPE_VAR_1(ENUM, RETURN, ARG1)                      \
3194    builtin_types[(int) ENUM]                                             \
3195     = build_function_type (builtin_types[(int) RETURN],          \
3196                            tree_cons (NULL_TREE,                         \
3197                                       builtin_types[(int) ARG1],         \
3198                                       NULL_TREE));
3199
3200 #define DEF_FUNCTION_TYPE_VAR_2(ENUM, RETURN, ARG1, ARG2)       \
3201    builtin_types[(int) ENUM]                                    \
3202     = build_function_type                                       \
3203       (builtin_types[(int) RETURN],                             \
3204        tree_cons (NULL_TREE,                                    \
3205                   builtin_types[(int) ARG1],                    \
3206                   tree_cons (NULL_TREE,                         \
3207                              builtin_types[(int) ARG2],         \
3208                              NULL_TREE)));
3209
3210 #define DEF_FUNCTION_TYPE_VAR_3(ENUM, RETURN, ARG1, ARG2, ARG3)         \
3211    builtin_types[(int) ENUM]                                            \
3212     = build_function_type                                               \
3213       (builtin_types[(int) RETURN],                                     \
3214        tree_cons (NULL_TREE,                                            \
3215                   builtin_types[(int) ARG1],                            \
3216                   tree_cons (NULL_TREE,                                 \
3217                              builtin_types[(int) ARG2],                 \
3218                              tree_cons (NULL_TREE,                      \
3219                                         builtin_types[(int) ARG3],      \
3220                                         NULL_TREE))));
3221
3222 #define DEF_POINTER_TYPE(ENUM, TYPE)                    \
3223   builtin_types[(int) ENUM]                             \
3224     = build_pointer_type (builtin_types[(int) TYPE]);
3225 #include "builtin-types.def"
3226 #undef DEF_PRIMITIVE_TYPE
3227 #undef DEF_FUNCTION_TYPE_1
3228 #undef DEF_FUNCTION_TYPE_2
3229 #undef DEF_FUNCTION_TYPE_3
3230 #undef DEF_FUNCTION_TYPE_4
3231 #undef DEF_FUNCTION_TYPE_VAR_0
3232 #undef DEF_FUNCTION_TYPE_VAR_1
3233 #undef DEF_FUNCTION_TYPE_VAR_2
3234 #undef DEF_FUNCTION_TYPE_VAR_3
3235 #undef DEF_POINTER_TYPE
3236
3237   c_init_attributes ();
3238
3239 #define DEF_BUILTIN(ENUM, NAME, CLASS, TYPE, LIBTYPE, BOTH_P, FALLBACK_P, \
3240                     NONANSI_P, ATTRS, IMPLICIT, COND)                   \
3241   if (NAME && COND)                                                     \
3242     {                                                                   \
3243       tree decl;                                                        \
3244                                                                         \
3245       gcc_assert ((!BOTH_P && !FALLBACK_P)                              \
3246                   || !strncmp (NAME, "__builtin_",                      \
3247                                strlen ("__builtin_")));                 \
3248                                                                         \
3249       if (!BOTH_P)                                                      \
3250         decl = lang_hooks.builtin_function (NAME, builtin_types[TYPE],  \
3251                                  ENUM,                                  \
3252                                  CLASS,                                 \
3253                                  (FALLBACK_P                            \
3254                                   ? (NAME + strlen ("__builtin_"))      \
3255                                   : NULL),                              \
3256                                  built_in_attributes[(int) ATTRS]);     \
3257       else                                                              \
3258         decl = builtin_function_2 (NAME,                                \
3259                                    NAME + strlen ("__builtin_"),        \
3260                                    builtin_types[TYPE],                 \
3261                                    builtin_types[LIBTYPE],              \
3262                                    ENUM,                                \
3263                                    CLASS,                               \
3264                                    FALLBACK_P,                          \
3265                                    NONANSI_P,                           \
3266                                    built_in_attributes[(int) ATTRS]);   \
3267                                                                         \
3268       built_in_decls[(int) ENUM] = decl;                                \
3269       if (IMPLICIT)                                                     \
3270         implicit_built_in_decls[(int) ENUM] = decl;                     \
3271     }
3272 #include "builtins.def"
3273 #undef DEF_BUILTIN
3274
3275   build_common_builtin_nodes ();
3276
3277   targetm.init_builtins ();
3278   if (flag_mudflap)
3279     mudflap_init ();
3280
3281   main_identifier_node = get_identifier ("main");
3282 }
3283
3284 /* Look up the function in built_in_decls that corresponds to DECL
3285    and set ASMSPEC as its user assembler name.  DECL must be a
3286    function decl that declares a builtin.  */
3287
3288 void
3289 set_builtin_user_assembler_name (tree decl, const char *asmspec)
3290 {
3291   tree builtin;
3292   gcc_assert (TREE_CODE (decl) == FUNCTION_DECL
3293               && DECL_BUILT_IN_CLASS (decl) == BUILT_IN_NORMAL
3294               && asmspec != 0);
3295
3296   builtin = built_in_decls [DECL_FUNCTION_CODE (decl)];
3297   set_user_assembler_name (builtin, asmspec);
3298   if (DECL_FUNCTION_CODE (decl) == BUILT_IN_MEMCPY)
3299     init_block_move_fn (asmspec);
3300   else if (DECL_FUNCTION_CODE (decl) == BUILT_IN_MEMSET)
3301     init_block_clear_fn (asmspec);
3302 }
3303
3304 tree
3305 build_va_arg (tree expr, tree type)
3306 {
3307   return build1 (VA_ARG_EXPR, type, expr);
3308 }
3309
3310
3311 /* Linked list of disabled built-in functions.  */
3312
3313 typedef struct disabled_builtin
3314 {
3315   const char *name;
3316   struct disabled_builtin *next;
3317 } disabled_builtin;
3318 static disabled_builtin *disabled_builtins = NULL;
3319
3320 static bool builtin_function_disabled_p (const char *);
3321
3322 /* Disable a built-in function specified by -fno-builtin-NAME.  If NAME
3323    begins with "__builtin_", give an error.  */
3324
3325 void
3326 disable_builtin_function (const char *name)
3327 {
3328   if (strncmp (name, "__builtin_", strlen ("__builtin_")) == 0)
3329     error ("cannot disable built-in function %qs", name);
3330   else
3331     {
3332       disabled_builtin *new_disabled_builtin = XNEW (disabled_builtin);
3333       new_disabled_builtin->name = name;
3334       new_disabled_builtin->next = disabled_builtins;
3335       disabled_builtins = new_disabled_builtin;
3336     }
3337 }
3338
3339
3340 /* Return true if the built-in function NAME has been disabled, false
3341    otherwise.  */
3342
3343 static bool
3344 builtin_function_disabled_p (const char *name)
3345 {
3346   disabled_builtin *p;
3347   for (p = disabled_builtins; p != NULL; p = p->next)
3348     {
3349       if (strcmp (name, p->name) == 0)
3350         return true;
3351     }
3352   return false;
3353 }
3354
3355
3356 /* Possibly define a builtin function with one or two names.  BUILTIN_NAME
3357    is an __builtin_-prefixed name; NAME is the ordinary name; one or both
3358    of these may be NULL (though both being NULL is useless).
3359    BUILTIN_TYPE is the type of the __builtin_-prefixed function;
3360    TYPE is the type of the function with the ordinary name.  These
3361    may differ if the ordinary name is declared with a looser type to avoid
3362    conflicts with headers.  FUNCTION_CODE and CL are as for
3363    builtin_function.  If LIBRARY_NAME_P is nonzero, NAME is passed as
3364    the LIBRARY_NAME parameter to builtin_function when declaring BUILTIN_NAME.
3365    If NONANSI_P is true, the name NAME is treated as a non-ANSI name;
3366    ATTRS is the tree list representing the builtin's function attributes.
3367    Returns the declaration of BUILTIN_NAME, if any, otherwise
3368    the declaration of NAME.  Does not declare NAME if flag_no_builtin,
3369    or if NONANSI_P and flag_no_nonansi_builtin.  */
3370
3371 static tree
3372 builtin_function_2 (const char *builtin_name, const char *name,
3373                     tree builtin_type, tree type,
3374                     enum built_in_function function_code,
3375                     enum built_in_class cl, int library_name_p,
3376                     bool nonansi_p, tree attrs)
3377 {
3378   tree bdecl = NULL_TREE;
3379   tree decl = NULL_TREE;
3380
3381   if (builtin_name != 0)
3382     bdecl = lang_hooks.builtin_function (builtin_name, builtin_type,
3383                                          function_code, cl,
3384                                          library_name_p ? name : NULL, attrs);
3385
3386   if (name != 0 && !flag_no_builtin && !builtin_function_disabled_p (name)
3387       && !(nonansi_p && flag_no_nonansi_builtin))
3388     decl = lang_hooks.builtin_function (name, type, function_code, cl,
3389                                         NULL, attrs);
3390
3391   return (bdecl != 0 ? bdecl : decl);
3392 }
3393 \f
3394 /* Nonzero if the type T promotes to int.  This is (nearly) the
3395    integral promotions defined in ISO C99 6.3.1.1/2.  */
3396
3397 bool
3398 c_promoting_integer_type_p (tree t)
3399 {
3400   switch (TREE_CODE (t))
3401     {
3402     case INTEGER_TYPE:
3403       return (TYPE_MAIN_VARIANT (t) == char_type_node
3404               || TYPE_MAIN_VARIANT (t) == signed_char_type_node
3405               || TYPE_MAIN_VARIANT (t) == unsigned_char_type_node
3406               || TYPE_MAIN_VARIANT (t) == short_integer_type_node
3407               || TYPE_MAIN_VARIANT (t) == short_unsigned_type_node
3408               || TYPE_PRECISION (t) < TYPE_PRECISION (integer_type_node));
3409
3410     case ENUMERAL_TYPE:
3411       /* ??? Technically all enumerations not larger than an int
3412          promote to an int.  But this is used along code paths
3413          that only want to notice a size change.  */
3414       return TYPE_PRECISION (t) < TYPE_PRECISION (integer_type_node);
3415
3416     case BOOLEAN_TYPE:
3417       return 1;
3418
3419     default:
3420       return 0;
3421     }
3422 }
3423
3424 /* Return 1 if PARMS specifies a fixed number of parameters
3425    and none of their types is affected by default promotions.  */
3426
3427 int
3428 self_promoting_args_p (tree parms)
3429 {
3430   tree t;
3431   for (t = parms; t; t = TREE_CHAIN (t))
3432     {
3433       tree type = TREE_VALUE (t);
3434
3435       if (TREE_CHAIN (t) == 0 && type != void_type_node)
3436         return 0;
3437
3438       if (type == 0)
3439         return 0;
3440
3441       if (TYPE_MAIN_VARIANT (type) == float_type_node)
3442         return 0;
3443
3444       if (c_promoting_integer_type_p (type))
3445         return 0;
3446     }
3447   return 1;
3448 }
3449
3450 /* Recursively examines the array elements of TYPE, until a non-array
3451    element type is found.  */
3452
3453 tree
3454 strip_array_types (tree type)
3455 {
3456   while (TREE_CODE (type) == ARRAY_TYPE)
3457     type = TREE_TYPE (type);
3458
3459   return type;
3460 }
3461
3462 /* Recursively remove any '*' or '&' operator from TYPE.  */
3463 tree
3464 strip_pointer_operator (tree t)
3465 {
3466   while (POINTER_TYPE_P (t))
3467     t = TREE_TYPE (t);
3468   return t;
3469 }
3470
3471 /* Used to compare case labels.  K1 and K2 are actually tree nodes
3472    representing case labels, or NULL_TREE for a `default' label.
3473    Returns -1 if K1 is ordered before K2, -1 if K1 is ordered after
3474    K2, and 0 if K1 and K2 are equal.  */
3475
3476 int
3477 case_compare (splay_tree_key k1, splay_tree_key k2)
3478 {
3479   /* Consider a NULL key (such as arises with a `default' label) to be
3480      smaller than anything else.  */
3481   if (!k1)
3482     return k2 ? -1 : 0;
3483   else if (!k2)
3484     return k1 ? 1 : 0;
3485
3486   return tree_int_cst_compare ((tree) k1, (tree) k2);
3487 }
3488
3489 /* Process a case label for the range LOW_VALUE ... HIGH_VALUE.  If
3490    LOW_VALUE and HIGH_VALUE are both NULL_TREE then this case label is
3491    actually a `default' label.  If only HIGH_VALUE is NULL_TREE, then
3492    case label was declared using the usual C/C++ syntax, rather than
3493    the GNU case range extension.  CASES is a tree containing all the
3494    case ranges processed so far; COND is the condition for the
3495    switch-statement itself.  Returns the CASE_LABEL_EXPR created, or
3496    ERROR_MARK_NODE if no CASE_LABEL_EXPR is created.  */
3497
3498 tree
3499 c_add_case_label (splay_tree cases, tree cond, tree orig_type,
3500                   tree low_value, tree high_value)
3501 {
3502   tree type;
3503   tree label;
3504   tree case_label;
3505   splay_tree_node node;
3506
3507   /* Create the LABEL_DECL itself.  */
3508   label = create_artificial_label ();
3509
3510   /* If there was an error processing the switch condition, bail now
3511      before we get more confused.  */
3512   if (!cond || cond == error_mark_node)
3513     goto error_out;
3514
3515   if ((low_value && TREE_TYPE (low_value)
3516        && POINTER_TYPE_P (TREE_TYPE (low_value)))
3517       || (high_value && TREE_TYPE (high_value)
3518           && POINTER_TYPE_P (TREE_TYPE (high_value))))
3519     {
3520       error ("pointers are not permitted as case values");
3521       goto error_out;
3522     }
3523
3524   /* Case ranges are a GNU extension.  */
3525   if (high_value && pedantic)
3526     pedwarn ("range expressions in switch statements are non-standard");
3527
3528   type = TREE_TYPE (cond);
3529   if (low_value)
3530     {
3531       low_value = check_case_value (low_value);
3532       low_value = convert_and_check (type, low_value);
3533     }
3534   if (high_value)
3535     {
3536       high_value = check_case_value (high_value);
3537       high_value = convert_and_check (type, high_value);
3538     }
3539
3540   /* If an error has occurred, bail out now.  */
3541   if (low_value == error_mark_node || high_value == error_mark_node)
3542     goto error_out;
3543
3544   /* If the LOW_VALUE and HIGH_VALUE are the same, then this isn't
3545      really a case range, even though it was written that way.  Remove
3546      the HIGH_VALUE to simplify later processing.  */
3547   if (tree_int_cst_equal (low_value, high_value))
3548     high_value = NULL_TREE;
3549   if (low_value && high_value
3550       && !tree_int_cst_lt (low_value, high_value))
3551     warning ("empty range specified");
3552
3553   /* See if the case is in range of the type of the original testing
3554      expression.  If both low_value and high_value are out of range,
3555      don't insert the case label and return NULL_TREE.  */
3556   if (low_value
3557       && !check_case_bounds (type, orig_type,
3558                              &low_value, high_value ? &high_value : NULL))
3559     return NULL_TREE;
3560
3561   /* Look up the LOW_VALUE in the table of case labels we already
3562      have.  */
3563   node = splay_tree_lookup (cases, (splay_tree_key) low_value);
3564   /* If there was not an exact match, check for overlapping ranges.
3565      There's no need to do this if there's no LOW_VALUE or HIGH_VALUE;
3566      that's a `default' label and the only overlap is an exact match.  */
3567   if (!node && (low_value || high_value))
3568     {
3569       splay_tree_node low_bound;
3570       splay_tree_node high_bound;
3571
3572       /* Even though there wasn't an exact match, there might be an
3573          overlap between this case range and another case range.
3574          Since we've (inductively) not allowed any overlapping case
3575          ranges, we simply need to find the greatest low case label
3576          that is smaller that LOW_VALUE, and the smallest low case
3577          label that is greater than LOW_VALUE.  If there is an overlap
3578          it will occur in one of these two ranges.  */
3579       low_bound = splay_tree_predecessor (cases,
3580                                           (splay_tree_key) low_value);
3581       high_bound = splay_tree_successor (cases,
3582                                          (splay_tree_key) low_value);
3583
3584       /* Check to see if the LOW_BOUND overlaps.  It is smaller than
3585          the LOW_VALUE, so there is no need to check unless the
3586          LOW_BOUND is in fact itself a case range.  */
3587       if (low_bound
3588           && CASE_HIGH ((tree) low_bound->value)
3589           && tree_int_cst_compare (CASE_HIGH ((tree) low_bound->value),
3590                                     low_value) >= 0)
3591         node = low_bound;
3592       /* Check to see if the HIGH_BOUND overlaps.  The low end of that
3593          range is bigger than the low end of the current range, so we
3594          are only interested if the current range is a real range, and
3595          not an ordinary case label.  */
3596       else if (high_bound
3597                && high_value
3598                && (tree_int_cst_compare ((tree) high_bound->key,
3599                                          high_value)
3600                    <= 0))
3601         node = high_bound;
3602     }
3603   /* If there was an overlap, issue an error.  */
3604   if (node)
3605     {
3606       tree duplicate = CASE_LABEL ((tree) node->value);
3607
3608       if (high_value)
3609         {
3610           error ("duplicate (or overlapping) case value");
3611           error ("%Jthis is the first entry overlapping that value", duplicate);
3612         }
3613       else if (low_value)
3614         {
3615           error ("duplicate case value") ;
3616           error ("%Jpreviously used here", duplicate);
3617         }
3618       else
3619         {
3620           error ("multiple default labels in one switch");
3621           error ("%Jthis is the first default label", duplicate);
3622         }
3623       goto error_out;
3624     }
3625
3626   /* Add a CASE_LABEL to the statement-tree.  */
3627   case_label = add_stmt (build_case_label (low_value, high_value, label));
3628   /* Register this case label in the splay tree.  */
3629   splay_tree_insert (cases,
3630                      (splay_tree_key) low_value,
3631                      (splay_tree_value) case_label);
3632
3633   return case_label;
3634
3635  error_out:
3636   /* Add a label so that the back-end doesn't think that the beginning of
3637      the switch is unreachable.  Note that we do not add a case label, as
3638      that just leads to duplicates and thence to aborts later on.  */
3639   if (!cases->root)
3640     {
3641       tree t = create_artificial_label ();
3642       add_stmt (build_stmt (LABEL_EXPR, t));
3643     }
3644   return error_mark_node;
3645 }
3646
3647 /* Subroutines of c_do_switch_warnings, called via splay_tree_foreach.
3648    Used to verify that case values match up with enumerator values.  */
3649
3650 static void
3651 match_case_to_enum_1 (tree key, tree type, tree label)
3652 {
3653   char buf[2 + 2*HOST_BITS_PER_WIDE_INT/4 + 1];
3654
3655   /* ??? Not working too hard to print the double-word value.
3656      Should perhaps be done with %lwd in the diagnostic routines?  */
3657   if (TREE_INT_CST_HIGH (key) == 0)
3658     snprintf (buf, sizeof (buf), HOST_WIDE_INT_PRINT_UNSIGNED,
3659               TREE_INT_CST_LOW (key));
3660   else if (!TYPE_UNSIGNED (type)
3661            && TREE_INT_CST_HIGH (key) == -1
3662            && TREE_INT_CST_LOW (key) != 0)
3663     snprintf (buf, sizeof (buf), "-" HOST_WIDE_INT_PRINT_UNSIGNED,
3664               -TREE_INT_CST_LOW (key));
3665   else
3666     snprintf (buf, sizeof (buf), HOST_WIDE_INT_PRINT_DOUBLE_HEX,
3667               TREE_INT_CST_HIGH (key), TREE_INT_CST_LOW (key));
3668
3669   if (TYPE_NAME (type) == 0)
3670     warning ("%Jcase value %qs not in enumerated type",
3671              CASE_LABEL (label), buf);
3672   else
3673     warning ("%Jcase value %qs not in enumerated type %qT",
3674              CASE_LABEL (label), buf, type);
3675 }
3676
3677 static int
3678 match_case_to_enum (splay_tree_node node, void *data)
3679 {
3680   tree label = (tree) node->value;
3681   tree type = (tree) data;
3682
3683   /* Skip default case.  */
3684   if (!CASE_LOW (label))
3685     return 0;
3686
3687   /* If TREE_ADDRESSABLE is not set, that means CASE_LOW did not appear
3688      when we did our enum->case scan.  Reset our scratch bit after.  */
3689   if (!TREE_ADDRESSABLE (label))
3690     match_case_to_enum_1 (CASE_LOW (label), type, label);
3691   else
3692     TREE_ADDRESSABLE (label) = 0;
3693
3694   /* If CASE_HIGH is non-null, we have a range.  Here we must search.
3695      Note that the old code in stmt.c did not check for the values in
3696      the range either, just the endpoints.  */
3697   if (CASE_HIGH (label))
3698     {
3699       tree chain, key = CASE_HIGH (label);
3700
3701       for (chain = TYPE_VALUES (type);
3702            chain && !tree_int_cst_equal (key, TREE_VALUE (chain));
3703            chain = TREE_CHAIN (chain))
3704         continue;
3705       if (!chain)
3706         match_case_to_enum_1 (key, type, label);
3707     }
3708
3709   return 0;
3710 }
3711
3712 /* Handle -Wswitch*.  Called from the front end after parsing the
3713    switch construct.  */
3714 /* ??? Should probably be somewhere generic, since other languages
3715    besides C and C++ would want this.  At the moment, however, C/C++
3716    are the only tree-ssa languages that support enumerations at all,
3717    so the point is moot.  */
3718
3719 void
3720 c_do_switch_warnings (splay_tree cases, location_t switch_location,
3721                       tree type, tree cond)
3722 {
3723   splay_tree_node default_node;
3724
3725   if (!warn_switch && !warn_switch_enum && !warn_switch_default)
3726     return;
3727
3728   default_node = splay_tree_lookup (cases, (splay_tree_key) NULL);
3729   if (warn_switch_default && !default_node)
3730     warning ("%Hswitch missing default case", &switch_location);
3731
3732   /* If the switch expression was an enumerated type, check that
3733      exactly all enumeration literals are covered by the cases.
3734      The check is made when -Wswitch was specified and there is no
3735      default case, or when -Wswitch-enum was specified.  */
3736   if (((warn_switch && !default_node) || warn_switch_enum)
3737       && type && TREE_CODE (type) == ENUMERAL_TYPE
3738       && TREE_CODE (cond) != INTEGER_CST)
3739     {
3740       tree chain;
3741
3742       /* The time complexity here is O(N*lg(N)) worst case, but for the
3743          common case of monotonically increasing enumerators, it is
3744          O(N), since the nature of the splay tree will keep the next
3745          element adjacent to the root at all times.  */
3746
3747       for (chain = TYPE_VALUES (type); chain; chain = TREE_CHAIN (chain))
3748         {
3749           splay_tree_node node
3750             = splay_tree_lookup (cases, (splay_tree_key) TREE_VALUE (chain));
3751
3752           if (node)
3753             {
3754               /* Mark the CASE_LOW part of the case entry as seen, so
3755                  that we save time later.  Choose TREE_ADDRESSABLE
3756                  randomly as a bit that won't have been set to-date.  */
3757               tree label = (tree) node->value;
3758               TREE_ADDRESSABLE (label) = 1;
3759             }
3760           else
3761             {
3762               /* Warn if there are enumerators that don't correspond to
3763                  case expressions.  */
3764               warning ("%Henumeration value %qE not handled in switch",
3765                        &switch_location, TREE_PURPOSE (chain));
3766             }
3767         }
3768
3769       /* Warn if there are case expressions that don't correspond to
3770          enumerators.  This can occur since C and C++ don't enforce
3771          type-checking of assignments to enumeration variables.
3772
3773          The time complexity here is O(N**2) worst case, since we've
3774          not sorted the enumeration values.  However, in the absence
3775          of case ranges this is O(N), since all single cases that
3776          corresponded to enumerations have been marked above.  */
3777
3778       splay_tree_foreach (cases, match_case_to_enum, type);
3779     }
3780 }
3781
3782 /* Finish an expression taking the address of LABEL (an
3783    IDENTIFIER_NODE).  Returns an expression for the address.  */
3784
3785 tree
3786 finish_label_address_expr (tree label)
3787 {
3788   tree result;
3789
3790   if (pedantic)
3791     pedwarn ("taking the address of a label is non-standard");
3792
3793   if (label == error_mark_node)
3794     return error_mark_node;
3795
3796   label = lookup_label (label);
3797   if (label == NULL_TREE)
3798     result = null_pointer_node;
3799   else
3800     {
3801       TREE_USED (label) = 1;
3802       result = build1 (ADDR_EXPR, ptr_type_node, label);
3803       /* The current function in not necessarily uninlinable.
3804          Computed gotos are incompatible with inlining, but the value
3805          here could be used only in a diagnostic, for example.  */
3806     }
3807
3808   return result;
3809 }
3810
3811 /* Hook used by expand_expr to expand language-specific tree codes.  */
3812 /* The only things that should go here are bits needed to expand
3813    constant initializers.  Everything else should be handled by the
3814    gimplification routines.  */
3815
3816 rtx
3817 c_expand_expr (tree exp, rtx target, enum machine_mode tmode,
3818                int modifier /* Actually enum_modifier.  */,
3819                rtx *alt_rtl)
3820 {
3821   switch (TREE_CODE (exp))
3822     {
3823     case COMPOUND_LITERAL_EXPR:
3824       {
3825         /* Initialize the anonymous variable declared in the compound
3826            literal, then return the variable.  */
3827         tree decl = COMPOUND_LITERAL_EXPR_DECL (exp);
3828         emit_local_var (decl);
3829         return expand_expr_real (decl, target, tmode, modifier, alt_rtl);
3830       }
3831
3832     default:
3833       gcc_unreachable ();
3834     }
3835 }
3836
3837 /* Hook used by staticp to handle language-specific tree codes.  */
3838
3839 tree
3840 c_staticp (tree exp)
3841 {
3842   return (TREE_CODE (exp) == COMPOUND_LITERAL_EXPR
3843           && TREE_STATIC (COMPOUND_LITERAL_EXPR_DECL (exp))
3844           ? exp : NULL);
3845 }
3846 \f
3847
3848 /* Given a boolean expression ARG, return a tree representing an increment
3849    or decrement (as indicated by CODE) of ARG.  The front end must check for
3850    invalid cases (e.g., decrement in C++).  */
3851 tree
3852 boolean_increment (enum tree_code code, tree arg)
3853 {
3854   tree val;
3855   tree true_res = boolean_true_node;
3856
3857   arg = stabilize_reference (arg);
3858   switch (code)
3859     {
3860     case PREINCREMENT_EXPR:
3861       val = build2 (MODIFY_EXPR, TREE_TYPE (arg), arg, true_res);
3862       break;
3863     case POSTINCREMENT_EXPR:
3864       val = build2 (MODIFY_EXPR, TREE_TYPE (arg), arg, true_res);
3865       arg = save_expr (arg);
3866       val = build2 (COMPOUND_EXPR, TREE_TYPE (arg), val, arg);
3867       val = build2 (COMPOUND_EXPR, TREE_TYPE (arg), arg, val);
3868       break;
3869     case PREDECREMENT_EXPR:
3870       val = build2 (MODIFY_EXPR, TREE_TYPE (arg), arg,
3871                     invert_truthvalue (arg));
3872       break;
3873     case POSTDECREMENT_EXPR:
3874       val = build2 (MODIFY_EXPR, TREE_TYPE (arg), arg,
3875                     invert_truthvalue (arg));
3876       arg = save_expr (arg);
3877       val = build2 (COMPOUND_EXPR, TREE_TYPE (arg), val, arg);
3878       val = build2 (COMPOUND_EXPR, TREE_TYPE (arg), arg, val);
3879       break;
3880     default:
3881       gcc_unreachable ();
3882     }
3883   TREE_SIDE_EFFECTS (val) = 1;
3884   return val;
3885 }
3886 \f
3887 /* Built-in macros for stddef.h, that require macros defined in this
3888    file.  */
3889 void
3890 c_stddef_cpp_builtins(void)
3891 {
3892   builtin_define_with_value ("__SIZE_TYPE__", SIZE_TYPE, 0);
3893   builtin_define_with_value ("__PTRDIFF_TYPE__", PTRDIFF_TYPE, 0);
3894   builtin_define_with_value ("__WCHAR_TYPE__", MODIFIED_WCHAR_TYPE, 0);
3895   builtin_define_with_value ("__WINT_TYPE__", WINT_TYPE, 0);
3896   builtin_define_with_value ("__INTMAX_TYPE__", INTMAX_TYPE, 0);
3897   builtin_define_with_value ("__UINTMAX_TYPE__", UINTMAX_TYPE, 0);
3898 }
3899
3900 static void
3901 c_init_attributes (void)
3902 {
3903   /* Fill in the built_in_attributes array.  */
3904 #define DEF_ATTR_NULL_TREE(ENUM)                                \
3905   built_in_attributes[(int) ENUM] = NULL_TREE;
3906 #define DEF_ATTR_INT(ENUM, VALUE)                               \
3907   built_in_attributes[(int) ENUM] = build_int_cst (NULL_TREE, VALUE);
3908 #define DEF_ATTR_IDENT(ENUM, STRING)                            \
3909   built_in_attributes[(int) ENUM] = get_identifier (STRING);
3910 #define DEF_ATTR_TREE_LIST(ENUM, PURPOSE, VALUE, CHAIN) \
3911   built_in_attributes[(int) ENUM]                       \
3912     = tree_cons (built_in_attributes[(int) PURPOSE],    \
3913                  built_in_attributes[(int) VALUE],      \
3914                  built_in_attributes[(int) CHAIN]);
3915 #include "builtin-attrs.def"
3916 #undef DEF_ATTR_NULL_TREE
3917 #undef DEF_ATTR_INT
3918 #undef DEF_ATTR_IDENT
3919 #undef DEF_ATTR_TREE_LIST
3920 }
3921
3922 /* Attribute handlers common to C front ends.  */
3923
3924 /* Handle a "packed" attribute; arguments as in
3925    struct attribute_spec.handler.  */
3926
3927 static tree
3928 handle_packed_attribute (tree *node, tree name, tree ARG_UNUSED (args),
3929                          int flags, bool *no_add_attrs)
3930 {
3931   if (TYPE_P (*node))
3932     {
3933       if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
3934         *node = build_variant_type_copy (*node);
3935       TYPE_PACKED (*node) = 1;
3936       if (TYPE_MAIN_VARIANT (*node) == *node)
3937         {
3938           /* If it is the main variant, then pack the other variants
3939              too. This happens in,
3940
3941              struct Foo {
3942                struct Foo const *ptr; // creates a variant w/o packed flag
3943                } __ attribute__((packed)); // packs it now.
3944           */
3945           tree probe;
3946
3947           for (probe = *node; probe; probe = TYPE_NEXT_VARIANT (probe))
3948             TYPE_PACKED (probe) = 1;
3949         }
3950
3951     }
3952   else if (TREE_CODE (*node) == FIELD_DECL)
3953     DECL_PACKED (*node) = 1;
3954   /* We can't set DECL_PACKED for a VAR_DECL, because the bit is
3955      used for DECL_REGISTER.  It wouldn't mean anything anyway.
3956      We can't set DECL_PACKED on the type of a TYPE_DECL, because
3957      that changes what the typedef is typing.  */
3958   else
3959     {
3960       warning ("%qE attribute ignored", name);
3961       *no_add_attrs = true;
3962     }
3963
3964   return NULL_TREE;
3965 }
3966
3967 /* Handle a "nocommon" attribute; arguments as in
3968    struct attribute_spec.handler.  */
3969
3970 static tree
3971 handle_nocommon_attribute (tree *node, tree name,
3972                            tree ARG_UNUSED (args),
3973                            int ARG_UNUSED (flags), bool *no_add_attrs)
3974 {
3975   if (TREE_CODE (*node) == VAR_DECL)
3976     DECL_COMMON (*node) = 0;
3977   else
3978     {
3979       warning ("%qE attribute ignored", name);
3980       *no_add_attrs = true;
3981     }
3982
3983   return NULL_TREE;
3984 }
3985
3986 /* Handle a "common" attribute; arguments as in
3987    struct attribute_spec.handler.  */
3988
3989 static tree
3990 handle_common_attribute (tree *node, tree name, tree ARG_UNUSED (args),
3991                          int ARG_UNUSED (flags), bool *no_add_attrs)
3992 {
3993   if (TREE_CODE (*node) == VAR_DECL)
3994     DECL_COMMON (*node) = 1;
3995   else
3996     {
3997       warning ("%qE attribute ignored", name);
3998       *no_add_attrs = true;
3999     }
4000
4001   return NULL_TREE;
4002 }
4003
4004 /* Handle a "noreturn" attribute; arguments as in
4005    struct attribute_spec.handler.  */
4006
4007 static tree
4008 handle_noreturn_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4009                            int ARG_UNUSED (flags), bool *no_add_attrs)
4010 {
4011   tree type = TREE_TYPE (*node);
4012
4013   /* See FIXME comment in c_common_attribute_table.  */
4014   if (TREE_CODE (*node) == FUNCTION_DECL)
4015     TREE_THIS_VOLATILE (*node) = 1;
4016   else if (TREE_CODE (type) == POINTER_TYPE
4017            && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE)
4018     TREE_TYPE (*node)
4019       = build_pointer_type
4020         (build_type_variant (TREE_TYPE (type),
4021                              TYPE_READONLY (TREE_TYPE (type)), 1));
4022   else
4023     {
4024       warning ("%qE attribute ignored", name);
4025       *no_add_attrs = true;
4026     }
4027
4028   return NULL_TREE;
4029 }
4030
4031 /* Handle a "noinline" attribute; arguments as in
4032    struct attribute_spec.handler.  */
4033
4034 static tree
4035 handle_noinline_attribute (tree *node, tree name,
4036                            tree ARG_UNUSED (args),
4037                            int ARG_UNUSED (flags), bool *no_add_attrs)
4038 {
4039   if (TREE_CODE (*node) == FUNCTION_DECL)
4040     DECL_UNINLINABLE (*node) = 1;
4041   else
4042     {
4043       warning ("%qE attribute ignored", name);
4044       *no_add_attrs = true;
4045     }
4046
4047   return NULL_TREE;
4048 }
4049
4050 /* Handle a "always_inline" attribute; arguments as in
4051    struct attribute_spec.handler.  */
4052
4053 static tree
4054 handle_always_inline_attribute (tree *node, tree name,
4055                                 tree ARG_UNUSED (args),
4056                                 int ARG_UNUSED (flags),
4057                                 bool *no_add_attrs)
4058 {
4059   if (TREE_CODE (*node) == FUNCTION_DECL)
4060     {
4061       /* Do nothing else, just set the attribute.  We'll get at
4062          it later with lookup_attribute.  */
4063     }
4064   else
4065     {
4066       warning ("%qE attribute ignored", name);
4067       *no_add_attrs = true;
4068     }
4069
4070   return NULL_TREE;
4071 }
4072
4073 /* Handle a "used" attribute; arguments as in
4074    struct attribute_spec.handler.  */
4075
4076 static tree
4077 handle_used_attribute (tree *pnode, tree name, tree ARG_UNUSED (args),
4078                        int ARG_UNUSED (flags), bool *no_add_attrs)
4079 {
4080   tree node = *pnode;
4081
4082   if (TREE_CODE (node) == FUNCTION_DECL
4083       || (TREE_CODE (node) == VAR_DECL && TREE_STATIC (node)))
4084     {
4085       TREE_USED (node) = 1;
4086       DECL_PRESERVE_P (node) = 1;
4087     }
4088   else
4089     {
4090       warning ("%qE attribute ignored", name);
4091       *no_add_attrs = true;
4092     }
4093
4094   return NULL_TREE;
4095 }
4096
4097 /* Handle a "unused" attribute; arguments as in
4098    struct attribute_spec.handler.  */
4099
4100 static tree
4101 handle_unused_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4102                          int flags, bool *no_add_attrs)
4103 {
4104   if (DECL_P (*node))
4105     {
4106       tree decl = *node;
4107
4108       if (TREE_CODE (decl) == PARM_DECL
4109           || TREE_CODE (decl) == VAR_DECL
4110           || TREE_CODE (decl) == FUNCTION_DECL
4111           || TREE_CODE (decl) == LABEL_DECL
4112           || TREE_CODE (decl) == TYPE_DECL)
4113         TREE_USED (decl) = 1;
4114       else
4115         {
4116           warning ("%qE attribute ignored", name);
4117           *no_add_attrs = true;
4118         }
4119     }
4120   else
4121     {
4122       if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
4123         *node = build_variant_type_copy (*node);
4124       TREE_USED (*node) = 1;
4125     }
4126
4127   return NULL_TREE;
4128 }
4129
4130 /* Handle a "const" attribute; arguments as in
4131    struct attribute_spec.handler.  */
4132
4133 static tree
4134 handle_const_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4135                         int ARG_UNUSED (flags), bool *no_add_attrs)
4136 {
4137   tree type = TREE_TYPE (*node);
4138
4139   /* See FIXME comment on noreturn in c_common_attribute_table.  */
4140   if (TREE_CODE (*node) == FUNCTION_DECL)
4141     TREE_READONLY (*node) = 1;
4142   else if (TREE_CODE (type) == POINTER_TYPE
4143            && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE)
4144     TREE_TYPE (*node)
4145       = build_pointer_type
4146         (build_type_variant (TREE_TYPE (type), 1,
4147                              TREE_THIS_VOLATILE (TREE_TYPE (type))));
4148   else
4149     {
4150       warning ("%qE attribute ignored", name);
4151       *no_add_attrs = true;
4152     }
4153
4154   return NULL_TREE;
4155 }
4156
4157 /* Handle a "transparent_union" attribute; arguments as in
4158    struct attribute_spec.handler.  */
4159
4160 static tree
4161 handle_transparent_union_attribute (tree *node, tree name,
4162                                     tree ARG_UNUSED (args), int flags,
4163                                     bool *no_add_attrs)
4164 {
4165   tree decl = NULL_TREE;
4166   tree *type = NULL;
4167   int is_type = 0;
4168
4169   if (DECL_P (*node))
4170     {
4171       decl = *node;
4172       type = &TREE_TYPE (decl);
4173       is_type = TREE_CODE (*node) == TYPE_DECL;
4174     }
4175   else if (TYPE_P (*node))
4176     type = node, is_type = 1;
4177
4178   if (is_type
4179       && TREE_CODE (*type) == UNION_TYPE
4180       && (decl == 0
4181           || (TYPE_FIELDS (*type) != 0
4182               && TYPE_MODE (*type) == DECL_MODE (TYPE_FIELDS (*type)))))
4183     {
4184       if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
4185         *type = build_variant_type_copy (*type);
4186       TYPE_TRANSPARENT_UNION (*type) = 1;
4187     }
4188   else if (decl != 0 && TREE_CODE (decl) == PARM_DECL
4189            && TREE_CODE (*type) == UNION_TYPE
4190            && TYPE_MODE (*type) == DECL_MODE (TYPE_FIELDS (*type)))
4191     DECL_TRANSPARENT_UNION (decl) = 1;
4192   else
4193     {
4194       warning ("%qE attribute ignored", name);
4195       *no_add_attrs = true;
4196     }
4197
4198   return NULL_TREE;
4199 }
4200
4201 /* Handle a "constructor" attribute; arguments as in
4202    struct attribute_spec.handler.  */
4203
4204 static tree
4205 handle_constructor_attribute (tree *node, tree name,
4206                               tree ARG_UNUSED (args),
4207                               int ARG_UNUSED (flags),
4208                               bool *no_add_attrs)
4209 {
4210   tree decl = *node;
4211   tree type = TREE_TYPE (decl);
4212
4213   if (TREE_CODE (decl) == FUNCTION_DECL
4214       && TREE_CODE (type) == FUNCTION_TYPE
4215       && decl_function_context (decl) == 0)
4216     {
4217       DECL_STATIC_CONSTRUCTOR (decl) = 1;
4218       TREE_USED (decl) = 1;
4219     }
4220   else
4221     {
4222       warning ("%qE attribute ignored", name);
4223       *no_add_attrs = true;
4224     }
4225
4226   return NULL_TREE;
4227 }
4228
4229 /* Handle a "destructor" attribute; arguments as in
4230    struct attribute_spec.handler.  */
4231
4232 static tree
4233 handle_destructor_attribute (tree *node, tree name,
4234                              tree ARG_UNUSED (args),
4235                              int ARG_UNUSED (flags),
4236                              bool *no_add_attrs)
4237 {
4238   tree decl = *node;
4239   tree type = TREE_TYPE (decl);
4240
4241   if (TREE_CODE (decl) == FUNCTION_DECL
4242       && TREE_CODE (type) == FUNCTION_TYPE
4243       && decl_function_context (decl) == 0)
4244     {
4245       DECL_STATIC_DESTRUCTOR (decl) = 1;
4246       TREE_USED (decl) = 1;
4247     }
4248   else
4249     {
4250       warning ("%qE attribute ignored", name);
4251       *no_add_attrs = true;
4252     }
4253
4254   return NULL_TREE;
4255 }
4256
4257 /* Handle a "mode" attribute; arguments as in
4258    struct attribute_spec.handler.  */
4259
4260 static tree
4261 handle_mode_attribute (tree *node, tree name, tree args,
4262                        int ARG_UNUSED (flags), bool *no_add_attrs)
4263 {
4264   tree type = *node;
4265
4266   *no_add_attrs = true;
4267
4268   if (TREE_CODE (TREE_VALUE (args)) != IDENTIFIER_NODE)
4269     warning ("%qE attribute ignored", name);
4270   else
4271     {
4272       int j;
4273       const char *p = IDENTIFIER_POINTER (TREE_VALUE (args));
4274       int len = strlen (p);
4275       enum machine_mode mode = VOIDmode;
4276       tree typefm;
4277       bool valid_mode;
4278
4279       if (len > 4 && p[0] == '_' && p[1] == '_'
4280           && p[len - 1] == '_' && p[len - 2] == '_')
4281         {
4282           char *newp = (char *) alloca (len - 1);
4283
4284           strcpy (newp, &p[2]);
4285           newp[len - 4] = '\0';
4286           p = newp;
4287         }
4288
4289       /* Change this type to have a type with the specified mode.
4290          First check for the special modes.  */
4291       if (!strcmp (p, "byte"))
4292         mode = byte_mode;
4293       else if (!strcmp (p, "word"))
4294         mode = word_mode;
4295       else if (!strcmp (p, "pointer"))
4296         mode = ptr_mode;
4297       else
4298         for (j = 0; j < NUM_MACHINE_MODES; j++)
4299           if (!strcmp (p, GET_MODE_NAME (j)))
4300             {
4301               mode = (enum machine_mode) j;
4302               break;
4303             }
4304
4305       if (mode == VOIDmode)
4306         {
4307           error ("unknown machine mode %qs", p);
4308           return NULL_TREE;
4309         }
4310
4311       valid_mode = false;
4312       switch (GET_MODE_CLASS (mode))
4313         {
4314         case MODE_INT:
4315         case MODE_PARTIAL_INT:
4316         case MODE_FLOAT:
4317           valid_mode = targetm.scalar_mode_supported_p (mode);
4318           break;
4319
4320         case MODE_COMPLEX_INT:
4321         case MODE_COMPLEX_FLOAT:
4322           valid_mode = targetm.scalar_mode_supported_p (GET_MODE_INNER (mode));
4323           break;
4324
4325         case MODE_VECTOR_INT:
4326         case MODE_VECTOR_FLOAT:
4327           warning ("specifying vector types with __attribute__ ((mode)) "
4328                    "is deprecated");
4329           warning ("use __attribute__ ((vector_size)) instead");
4330           valid_mode = vector_mode_valid_p (mode);
4331           break;
4332
4333         default:
4334           break;
4335         }
4336       if (!valid_mode)
4337         {
4338           error ("unable to emulate %qs", p);
4339           return NULL_TREE;
4340         }
4341
4342       if (POINTER_TYPE_P (type))
4343         {
4344           tree (*fn)(tree, enum machine_mode, bool);
4345
4346           if (!targetm.valid_pointer_mode (mode))
4347             {
4348               error ("invalid pointer mode %qs", p);
4349               return NULL_TREE;
4350             }
4351
4352           if (TREE_CODE (type) == POINTER_TYPE)
4353             fn = build_pointer_type_for_mode;
4354           else
4355             fn = build_reference_type_for_mode;
4356           typefm = fn (TREE_TYPE (type), mode, false);
4357         }
4358       else
4359         typefm = lang_hooks.types.type_for_mode (mode, TYPE_UNSIGNED (type));
4360
4361       if (typefm == NULL_TREE)
4362         {
4363           error ("no data type for mode %qs", p);
4364           return NULL_TREE;
4365         }
4366       else if (TREE_CODE (type) == ENUMERAL_TYPE)
4367         {
4368           /* For enumeral types, copy the precision from the integer
4369              type returned above.  If not an INTEGER_TYPE, we can't use
4370              this mode for this type.  */
4371           if (TREE_CODE (typefm) != INTEGER_TYPE)
4372             {
4373               error ("cannot use mode %qs for enumeral types", p);
4374               return NULL_TREE;
4375             }
4376
4377           if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
4378             type = build_variant_type_copy (type);
4379
4380           /* We cannot use layout_type here, because that will attempt
4381              to re-layout all variants, corrupting our original.  */
4382           TYPE_PRECISION (type) = TYPE_PRECISION (typefm);
4383           TYPE_MIN_VALUE (type) = TYPE_MIN_VALUE (typefm);
4384           TYPE_MAX_VALUE (type) = TYPE_MAX_VALUE (typefm);
4385           TYPE_SIZE (type) = TYPE_SIZE (typefm);
4386           TYPE_SIZE_UNIT (type) = TYPE_SIZE_UNIT (typefm);
4387           TYPE_MODE (type) = TYPE_MODE (typefm);
4388           if (!TYPE_USER_ALIGN (type))
4389             TYPE_ALIGN (type) = TYPE_ALIGN (typefm);
4390
4391           typefm = type;
4392         }
4393       else if (VECTOR_MODE_P (mode)
4394                ? TREE_CODE (type) != TREE_CODE (TREE_TYPE (typefm))
4395                : TREE_CODE (type) != TREE_CODE (typefm))
4396         {
4397           error ("mode %qs applied to inappropriate type", p);
4398           return NULL_TREE;
4399         }
4400
4401       *node = typefm;
4402     }
4403
4404   return NULL_TREE;
4405 }
4406
4407 /* Handle a "section" attribute; arguments as in
4408    struct attribute_spec.handler.  */
4409
4410 static tree
4411 handle_section_attribute (tree *node, tree ARG_UNUSED (name), tree args,
4412                           int ARG_UNUSED (flags), bool *no_add_attrs)
4413 {
4414   tree decl = *node;
4415
4416   if (targetm.have_named_sections)
4417     {
4418       user_defined_section_attribute = true;
4419
4420       if ((TREE_CODE (decl) == FUNCTION_DECL
4421            || TREE_CODE (decl) == VAR_DECL)
4422           && TREE_CODE (TREE_VALUE (args)) == STRING_CST)
4423         {
4424           if (TREE_CODE (decl) == VAR_DECL
4425               && current_function_decl != NULL_TREE
4426               && !TREE_STATIC (decl))
4427             {
4428               error ("%Jsection attribute cannot be specified for "
4429                      "local variables", decl);
4430               *no_add_attrs = true;
4431             }
4432
4433           /* The decl may have already been given a section attribute
4434              from a previous declaration.  Ensure they match.  */
4435           else if (DECL_SECTION_NAME (decl) != NULL_TREE
4436                    && strcmp (TREE_STRING_POINTER (DECL_SECTION_NAME (decl)),
4437                               TREE_STRING_POINTER (TREE_VALUE (args))) != 0)
4438             {
4439               error ("%Jsection of %qD conflicts with previous declaration",
4440                      *node, *node);
4441               *no_add_attrs = true;
4442             }
4443           else
4444             DECL_SECTION_NAME (decl) = TREE_VALUE (args);
4445         }
4446       else
4447         {
4448           error ("%Jsection attribute not allowed for %qD", *node, *node);
4449           *no_add_attrs = true;
4450         }
4451     }
4452   else
4453     {
4454       error ("%Jsection attributes are not supported for this target", *node);
4455       *no_add_attrs = true;
4456     }
4457
4458   return NULL_TREE;
4459 }
4460
4461 /* Handle a "aligned" attribute; arguments as in
4462    struct attribute_spec.handler.  */
4463
4464 static tree
4465 handle_aligned_attribute (tree *node, tree ARG_UNUSED (name), tree args,
4466                           int flags, bool *no_add_attrs)
4467 {
4468   tree decl = NULL_TREE;
4469   tree *type = NULL;
4470   int is_type = 0;
4471   tree align_expr = (args ? TREE_VALUE (args)
4472                      : size_int (BIGGEST_ALIGNMENT / BITS_PER_UNIT));
4473   int i;
4474
4475   if (DECL_P (*node))
4476     {
4477       decl = *node;
4478       type = &TREE_TYPE (decl);
4479       is_type = TREE_CODE (*node) == TYPE_DECL;
4480     }
4481   else if (TYPE_P (*node))
4482     type = node, is_type = 1;
4483
4484   if (TREE_CODE (align_expr) != INTEGER_CST)
4485     {
4486       error ("requested alignment is not a constant");
4487       *no_add_attrs = true;
4488     }
4489   else if ((i = tree_log2 (align_expr)) == -1)
4490     {
4491       error ("requested alignment is not a power of 2");
4492       *no_add_attrs = true;
4493     }
4494   else if (i > HOST_BITS_PER_INT - 2)
4495     {
4496       error ("requested alignment is too large");
4497       *no_add_attrs = true;
4498     }
4499   else if (is_type)
4500     {
4501       /* If we have a TYPE_DECL, then copy the type, so that we
4502          don't accidentally modify a builtin type.  See pushdecl.  */
4503       if (decl && TREE_TYPE (decl) != error_mark_node
4504           && DECL_ORIGINAL_TYPE (decl) == NULL_TREE)
4505         {
4506           tree tt = TREE_TYPE (decl);
4507           *type = build_variant_type_copy (*type);
4508           DECL_ORIGINAL_TYPE (decl) = tt;
4509           TYPE_NAME (*type) = decl;
4510           TREE_USED (*type) = TREE_USED (decl);
4511           TREE_TYPE (decl) = *type;
4512         }
4513       else if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
4514         *type = build_variant_type_copy (*type);
4515
4516       TYPE_ALIGN (*type) = (1 << i) * BITS_PER_UNIT;
4517       TYPE_USER_ALIGN (*type) = 1;
4518     }
4519   else if (TREE_CODE (decl) != VAR_DECL
4520            && TREE_CODE (decl) != FIELD_DECL)
4521     {
4522       error ("%Jalignment may not be specified for %qD", decl, decl);
4523       *no_add_attrs = true;
4524     }
4525   else
4526     {
4527       DECL_ALIGN (decl) = (1 << i) * BITS_PER_UNIT;
4528       DECL_USER_ALIGN (decl) = 1;
4529     }
4530
4531   return NULL_TREE;
4532 }
4533
4534 /* Handle a "weak" attribute; arguments as in
4535    struct attribute_spec.handler.  */
4536
4537 static tree
4538 handle_weak_attribute (tree *node, tree ARG_UNUSED (name),
4539                        tree ARG_UNUSED (args),
4540                        int ARG_UNUSED (flags),
4541                        bool * ARG_UNUSED (no_add_attrs))
4542 {
4543   declare_weak (*node);
4544
4545   return NULL_TREE;
4546 }
4547
4548 /* Handle an "alias" attribute; arguments as in
4549    struct attribute_spec.handler.  */
4550
4551 static tree
4552 handle_alias_attribute (tree *node, tree name, tree args,
4553                         int ARG_UNUSED (flags), bool *no_add_attrs)
4554 {
4555   tree decl = *node;
4556
4557   if ((TREE_CODE (decl) == FUNCTION_DECL && DECL_INITIAL (decl))
4558       || (TREE_CODE (decl) != FUNCTION_DECL && !DECL_EXTERNAL (decl)))
4559     {
4560       error ("%J%qD defined both normally and as an alias", decl, decl);
4561       *no_add_attrs = true;
4562     }
4563
4564   /* Note that the very first time we process a nested declaration,
4565      decl_function_context will not be set.  Indeed, *would* never
4566      be set except for the DECL_INITIAL/DECL_EXTERNAL frobbery that
4567      we do below.  After such frobbery, pushdecl would set the context.
4568      In any case, this is never what we want.  */
4569   else if (decl_function_context (decl) == 0 && current_function_decl == NULL)
4570     {
4571       tree id;
4572
4573       id = TREE_VALUE (args);
4574       if (TREE_CODE (id) != STRING_CST)
4575         {
4576           error ("alias argument not a string");
4577           *no_add_attrs = true;
4578           return NULL_TREE;
4579         }
4580       id = get_identifier (TREE_STRING_POINTER (id));
4581       /* This counts as a use of the object pointed to.  */
4582       TREE_USED (id) = 1;
4583
4584       if (TREE_CODE (decl) == FUNCTION_DECL)
4585         DECL_INITIAL (decl) = error_mark_node;
4586       else
4587         {
4588           DECL_EXTERNAL (decl) = 0;
4589           TREE_STATIC (decl) = 1;
4590         }
4591     }
4592   else
4593     {
4594       warning ("%qE attribute ignored", name);
4595       *no_add_attrs = true;
4596     }
4597
4598   return NULL_TREE;
4599 }
4600
4601 /* Handle an "visibility" attribute; arguments as in
4602    struct attribute_spec.handler.  */
4603
4604 static tree
4605 handle_visibility_attribute (tree *node, tree name, tree args,
4606                              int ARG_UNUSED (flags),
4607                              bool *no_add_attrs)
4608 {
4609   tree decl = *node;
4610   tree id = TREE_VALUE (args);
4611
4612   *no_add_attrs = true;
4613
4614   if (TYPE_P (*node))
4615     {
4616       if (TREE_CODE (*node) != RECORD_TYPE && TREE_CODE (*node) != UNION_TYPE)
4617        {
4618          warning ("%qE attribute ignored on non-class types", name);
4619          return NULL_TREE;
4620        }
4621     }
4622   else if (decl_function_context (decl) != 0 || !TREE_PUBLIC (decl))
4623     {
4624       warning ("%qE attribute ignored", name);
4625       return NULL_TREE;
4626     }
4627
4628   if (TREE_CODE (id) != STRING_CST)
4629     {
4630       error ("visibility argument not a string");
4631       return NULL_TREE;
4632     }
4633
4634   /*  If this is a type, set the visibility on the type decl.  */
4635   if (TYPE_P (decl))
4636     {
4637       decl = TYPE_NAME (decl);
4638       if (!decl)
4639         return NULL_TREE;
4640       if (TREE_CODE (decl) == IDENTIFIER_NODE)
4641         {
4642            warning ("%qE attribute ignored on types",
4643                     name);
4644            return NULL_TREE;
4645         }
4646     }
4647
4648   if (strcmp (TREE_STRING_POINTER (id), "default") == 0)
4649     DECL_VISIBILITY (decl) = VISIBILITY_DEFAULT;
4650   else if (strcmp (TREE_STRING_POINTER (id), "internal") == 0)
4651     DECL_VISIBILITY (decl) = VISIBILITY_INTERNAL;
4652   else if (strcmp (TREE_STRING_POINTER (id), "hidden") == 0)
4653     DECL_VISIBILITY (decl) = VISIBILITY_HIDDEN;
4654   else if (strcmp (TREE_STRING_POINTER (id), "protected") == 0)
4655     DECL_VISIBILITY (decl) = VISIBILITY_PROTECTED;
4656   else
4657     error ("visibility argument must be one of \"default\", \"hidden\", \"protected\" or \"internal\"");
4658   DECL_VISIBILITY_SPECIFIED (decl) = 1;
4659
4660   /* For decls only, go ahead and attach the attribute to the node as well.
4661      This is needed so we can determine whether we have VISIBILITY_DEFAULT
4662      because the visibility was not specified, or because it was explicitly
4663      overridden from the class visibility.  */
4664   if (DECL_P (*node))
4665     *no_add_attrs = false;
4666
4667   return NULL_TREE;
4668 }
4669
4670 /* Determine the ELF symbol visibility for DECL, which is either a
4671    variable or a function.  It is an error to use this function if a
4672    definition of DECL is not available in this translation unit.
4673    Returns true if the final visibility has been determined by this
4674    function; false if the caller is free to make additional
4675    modifications.  */
4676
4677 bool
4678 c_determine_visibility (tree decl)
4679 {
4680   gcc_assert (TREE_CODE (decl) == VAR_DECL
4681               || TREE_CODE (decl) == FUNCTION_DECL);
4682
4683   /* If the user explicitly specified the visibility with an
4684      attribute, honor that.  DECL_VISIBILITY will have been set during
4685      the processing of the attribute.  We check for an explicit
4686      attribute, rather than just checking DECL_VISIBILITY_SPECIFIED,
4687      to distinguish the use of an attribute from the use of a "#pragma
4688      GCC visibility push(...)"; in the latter case we still want other
4689      considerations to be able to overrule the #pragma.  */
4690   if (lookup_attribute ("visibility", DECL_ATTRIBUTES (decl)))
4691     return true;
4692
4693   /* Anything that is exported must have default visibility.  */
4694   if (TARGET_DLLIMPORT_DECL_ATTRIBUTES
4695       && lookup_attribute ("dllexport", DECL_ATTRIBUTES (decl)))
4696     {
4697       DECL_VISIBILITY (decl) = VISIBILITY_DEFAULT;
4698       DECL_VISIBILITY_SPECIFIED (decl) = 1;
4699       return true;
4700     }
4701
4702   return false;
4703 }
4704
4705 /* Handle an "tls_model" attribute; arguments as in
4706    struct attribute_spec.handler.  */
4707
4708 static tree
4709 handle_tls_model_attribute (tree *node, tree name, tree args,
4710                             int ARG_UNUSED (flags), bool *no_add_attrs)
4711 {
4712   tree decl = *node;
4713
4714   if (!DECL_THREAD_LOCAL (decl))
4715     {
4716       warning ("%qE attribute ignored", name);
4717       *no_add_attrs = true;
4718     }
4719   else
4720     {
4721       tree id;
4722
4723       id = TREE_VALUE (args);
4724       if (TREE_CODE (id) != STRING_CST)
4725         {
4726           error ("tls_model argument not a string");
4727           *no_add_attrs = true;
4728           return NULL_TREE;
4729         }
4730       if (strcmp (TREE_STRING_POINTER (id), "local-exec")
4731           && strcmp (TREE_STRING_POINTER (id), "initial-exec")
4732           && strcmp (TREE_STRING_POINTER (id), "local-dynamic")
4733           && strcmp (TREE_STRING_POINTER (id), "global-dynamic"))
4734         {
4735           error ("tls_model argument must be one of \"local-exec\", \"initial-exec\", \"local-dynamic\" or \"global-dynamic\"");
4736           *no_add_attrs = true;
4737           return NULL_TREE;
4738         }
4739     }
4740
4741   return NULL_TREE;
4742 }
4743
4744 /* Handle a "no_instrument_function" attribute; arguments as in
4745    struct attribute_spec.handler.  */
4746
4747 static tree
4748 handle_no_instrument_function_attribute (tree *node, tree name,
4749                                          tree ARG_UNUSED (args),
4750                                          int ARG_UNUSED (flags),
4751                                          bool *no_add_attrs)
4752 {
4753   tree decl = *node;
4754
4755   if (TREE_CODE (decl) != FUNCTION_DECL)
4756     {
4757       error ("%J%qE attribute applies only to functions", decl, name);
4758       *no_add_attrs = true;
4759     }
4760   else if (DECL_INITIAL (decl))
4761     {
4762       error ("%Jcan%'t set %qE attribute after definition", decl, name);
4763       *no_add_attrs = true;
4764     }
4765   else
4766     DECL_NO_INSTRUMENT_FUNCTION_ENTRY_EXIT (decl) = 1;
4767
4768   return NULL_TREE;
4769 }
4770
4771 /* Handle a "malloc" attribute; arguments as in
4772    struct attribute_spec.handler.  */
4773
4774 static tree
4775 handle_malloc_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4776                          int ARG_UNUSED (flags), bool *no_add_attrs)
4777 {
4778   if (TREE_CODE (*node) == FUNCTION_DECL
4779       && POINTER_TYPE_P (TREE_TYPE (TREE_TYPE (*node))))
4780     DECL_IS_MALLOC (*node) = 1;
4781   else
4782     {
4783       warning ("%qE attribute ignored", name);
4784       *no_add_attrs = true;
4785     }
4786
4787   return NULL_TREE;
4788 }
4789
4790 /* Handle a "returns_twice" attribute; arguments as in
4791    struct attribute_spec.handler.  */
4792
4793 static tree
4794 handle_returns_twice_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4795                          int ARG_UNUSED (flags), bool *no_add_attrs)
4796 {
4797   if (TREE_CODE (*node) == FUNCTION_DECL)
4798     DECL_IS_RETURNS_TWICE (*node) = 1;
4799   else
4800     {
4801       warning ("%qE attribute ignored", name);
4802       *no_add_attrs = true;
4803     }
4804
4805   return NULL_TREE;
4806 }
4807
4808 /* Handle a "no_limit_stack" attribute; arguments as in
4809    struct attribute_spec.handler.  */
4810
4811 static tree
4812 handle_no_limit_stack_attribute (tree *node, tree name,
4813                                  tree ARG_UNUSED (args),
4814                                  int ARG_UNUSED (flags),
4815                                  bool *no_add_attrs)
4816 {
4817   tree decl = *node;
4818
4819   if (TREE_CODE (decl) != FUNCTION_DECL)
4820     {
4821       error ("%J%qE attribute applies only to functions", decl, name);
4822       *no_add_attrs = true;
4823     }
4824   else if (DECL_INITIAL (decl))
4825     {
4826       error ("%Jcan%'t set %qE attribute after definition", decl, name);
4827       *no_add_attrs = true;
4828     }
4829   else
4830     DECL_NO_LIMIT_STACK (decl) = 1;
4831
4832   return NULL_TREE;
4833 }
4834
4835 /* Handle a "pure" attribute; arguments as in
4836    struct attribute_spec.handler.  */
4837
4838 static tree
4839 handle_pure_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4840                        int ARG_UNUSED (flags), bool *no_add_attrs)
4841 {
4842   if (TREE_CODE (*node) == FUNCTION_DECL)
4843     DECL_IS_PURE (*node) = 1;
4844   /* ??? TODO: Support types.  */
4845   else
4846     {
4847       warning ("%qE attribute ignored", name);
4848       *no_add_attrs = true;
4849     }
4850
4851   return NULL_TREE;
4852 }
4853
4854 /* Handle a "no vops" attribute; arguments as in
4855    struct attribute_spec.handler.  */
4856
4857 static tree
4858 handle_novops_attribute (tree *node, tree ARG_UNUSED (name),
4859                          tree ARG_UNUSED (args), int ARG_UNUSED (flags),
4860                          bool *ARG_UNUSED (no_add_attrs))
4861 {
4862   gcc_assert (TREE_CODE (*node) == FUNCTION_DECL);
4863   DECL_IS_NOVOPS (*node) = 1;
4864   return NULL_TREE;
4865 }
4866
4867 /* Handle a "deprecated" attribute; arguments as in
4868    struct attribute_spec.handler.  */
4869
4870 static tree
4871 handle_deprecated_attribute (tree *node, tree name,
4872                              tree ARG_UNUSED (args), int flags,
4873                              bool *no_add_attrs)
4874 {
4875   tree type = NULL_TREE;
4876   int warn = 0;
4877   tree what = NULL_TREE;
4878
4879   if (DECL_P (*node))
4880     {
4881       tree decl = *node;
4882       type = TREE_TYPE (decl);
4883
4884       if (TREE_CODE (decl) == TYPE_DECL
4885           || TREE_CODE (decl) == PARM_DECL
4886           || TREE_CODE (decl) == VAR_DECL
4887           || TREE_CODE (decl) == FUNCTION_DECL
4888           || TREE_CODE (decl) == FIELD_DECL)
4889         TREE_DEPRECATED (decl) = 1;
4890       else
4891         warn = 1;
4892     }
4893   else if (TYPE_P (*node))
4894     {
4895       if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
4896         *node = build_variant_type_copy (*node);
4897       TREE_DEPRECATED (*node) = 1;
4898       type = *node;
4899     }
4900   else
4901     warn = 1;
4902
4903   if (warn)
4904     {
4905       *no_add_attrs = true;
4906       if (type && TYPE_NAME (type))
4907         {
4908           if (TREE_CODE (TYPE_NAME (type)) == IDENTIFIER_NODE)
4909             what = TYPE_NAME (*node);
4910           else if (TREE_CODE (TYPE_NAME (type)) == TYPE_DECL
4911                    && DECL_NAME (TYPE_NAME (type)))
4912             what = DECL_NAME (TYPE_NAME (type));
4913         }
4914       if (what)
4915         warning ("%qE attribute ignored for %qE", name, what);
4916       else
4917         warning ("%qE attribute ignored", name);
4918     }
4919
4920   return NULL_TREE;
4921 }
4922
4923 /* Handle a "vector_size" attribute; arguments as in
4924    struct attribute_spec.handler.  */
4925
4926 static tree
4927 handle_vector_size_attribute (tree *node, tree name, tree args,
4928                               int ARG_UNUSED (flags),
4929                               bool *no_add_attrs)
4930 {
4931   unsigned HOST_WIDE_INT vecsize, nunits;
4932   enum machine_mode orig_mode;
4933   tree type = *node, new_type, size;
4934
4935   *no_add_attrs = true;
4936
4937   size = TREE_VALUE (args);
4938
4939   if (!host_integerp (size, 1))
4940     {
4941       warning ("%qE attribute ignored", name);
4942       return NULL_TREE;
4943     }
4944
4945   /* Get the vector size (in bytes).  */
4946   vecsize = tree_low_cst (size, 1);
4947
4948   /* We need to provide for vector pointers, vector arrays, and
4949      functions returning vectors.  For example:
4950
4951        __attribute__((vector_size(16))) short *foo;
4952
4953      In this case, the mode is SI, but the type being modified is
4954      HI, so we need to look further.  */
4955
4956   while (POINTER_TYPE_P (type)
4957          || TREE_CODE (type) == FUNCTION_TYPE
4958          || TREE_CODE (type) == METHOD_TYPE
4959          || TREE_CODE (type) == ARRAY_TYPE)
4960     type = TREE_TYPE (type);
4961
4962   /* Get the mode of the type being modified.  */
4963   orig_mode = TYPE_MODE (type);
4964
4965   if (TREE_CODE (type) == RECORD_TYPE
4966       || (GET_MODE_CLASS (orig_mode) != MODE_FLOAT
4967           && GET_MODE_CLASS (orig_mode) != MODE_INT)
4968       || !host_integerp (TYPE_SIZE_UNIT (type), 1))
4969     {
4970       error ("invalid vector type for attribute %qE", name);
4971       return NULL_TREE;
4972     }
4973
4974   /* Calculate how many units fit in the vector.  */
4975   nunits = vecsize / tree_low_cst (TYPE_SIZE_UNIT (type), 1);
4976   if (nunits & (nunits - 1))
4977     {
4978       error ("number of components of the vector not a power of two");
4979       return NULL_TREE;
4980     }
4981
4982   new_type = build_vector_type (type, nunits);
4983
4984   /* Build back pointers if needed.  */
4985   *node = reconstruct_complex_type (*node, new_type);
4986
4987   return NULL_TREE;
4988 }
4989
4990 /* Handle the "nonnull" attribute.  */
4991 static tree
4992 handle_nonnull_attribute (tree *node, tree ARG_UNUSED (name),
4993                           tree args, int ARG_UNUSED (flags),
4994                           bool *no_add_attrs)
4995 {
4996   tree type = *node;
4997   unsigned HOST_WIDE_INT attr_arg_num;
4998
4999   /* If no arguments are specified, all pointer arguments should be
5000      non-null.  Verify a full prototype is given so that the arguments
5001      will have the correct types when we actually check them later.  */
5002   if (!args)
5003     {
5004       if (!TYPE_ARG_TYPES (type))
5005         {
5006           error ("nonnull attribute without arguments on a non-prototype");
5007           *no_add_attrs = true;
5008         }
5009       return NULL_TREE;
5010     }
5011
5012   /* Argument list specified.  Verify that each argument number references
5013      a pointer argument.  */
5014   for (attr_arg_num = 1; args; args = TREE_CHAIN (args))
5015     {
5016       tree argument;
5017       unsigned HOST_WIDE_INT arg_num = 0, ck_num;
5018
5019       if (!get_nonnull_operand (TREE_VALUE (args), &arg_num))
5020         {
5021           error ("nonnull argument has invalid operand number (argument %lu)",
5022                  (unsigned long) attr_arg_num);
5023           *no_add_attrs = true;
5024           return NULL_TREE;
5025         }
5026
5027       argument = TYPE_ARG_TYPES (type);
5028       if (argument)
5029         {
5030           for (ck_num = 1; ; ck_num++)
5031             {
5032               if (!argument || ck_num == arg_num)
5033                 break;
5034               argument = TREE_CHAIN (argument);
5035             }
5036
5037           if (!argument
5038               || TREE_CODE (TREE_VALUE (argument)) == VOID_TYPE)
5039             {
5040               error ("nonnull argument with out-of-range operand number (argument %lu, operand %lu)",
5041                      (unsigned long) attr_arg_num, (unsigned long) arg_num);
5042               *no_add_attrs = true;
5043               return NULL_TREE;
5044             }
5045
5046           if (TREE_CODE (TREE_VALUE (argument)) != POINTER_TYPE)
5047             {
5048               error ("nonnull argument references non-pointer operand (argument %lu, operand %lu)",
5049                    (unsigned long) attr_arg_num, (unsigned long) arg_num);
5050               *no_add_attrs = true;
5051               return NULL_TREE;
5052             }
5053         }
5054     }
5055
5056   return NULL_TREE;
5057 }
5058
5059 /* Check the argument list of a function call for null in argument slots
5060    that are marked as requiring a non-null pointer argument.  */
5061
5062 static void
5063 check_function_nonnull (tree attrs, tree params)
5064 {
5065   tree a, args, param;
5066   int param_num;
5067
5068   for (a = attrs; a; a = TREE_CHAIN (a))
5069     {
5070       if (is_attribute_p ("nonnull", TREE_PURPOSE (a)))
5071         {
5072           args = TREE_VALUE (a);
5073
5074           /* Walk the argument list.  If we encounter an argument number we
5075              should check for non-null, do it.  If the attribute has no args,
5076              then every pointer argument is checked (in which case the check
5077              for pointer type is done in check_nonnull_arg).  */
5078           for (param = params, param_num = 1; ;
5079                param_num++, param = TREE_CHAIN (param))
5080             {
5081               if (!param)
5082         break;
5083               if (!args || nonnull_check_p (args, param_num))
5084         check_function_arguments_recurse (check_nonnull_arg, NULL,
5085                                           TREE_VALUE (param),
5086                                           param_num);
5087             }
5088         }
5089     }
5090 }
5091
5092 /* Check that the Nth argument of a function call (counting backwards
5093    from the end) is a (pointer)0.  */
5094
5095 static void
5096 check_function_sentinel (tree attrs, tree params)
5097 {
5098   tree attr = lookup_attribute ("sentinel", attrs);
5099
5100   if (attr)
5101     {
5102       if (!params)
5103         warning ("missing sentinel in function call");
5104       else
5105         {
5106           tree sentinel, end;
5107           unsigned pos = 0;
5108
5109           if (TREE_VALUE (attr))
5110             {
5111               tree p = TREE_VALUE (TREE_VALUE (attr));
5112               pos = TREE_INT_CST_LOW (p);
5113             }
5114
5115           sentinel = end = params;
5116
5117           /* Advance `end' ahead of `sentinel' by `pos' positions.  */
5118           while (pos > 0 && TREE_CHAIN (end))
5119             {
5120               pos--;
5121               end = TREE_CHAIN (end);
5122             }
5123           if (pos > 0)
5124             {
5125               warning ("not enough arguments to fit a sentinel");
5126               return;
5127             }
5128
5129           /* Now advance both until we find the last parameter.  */
5130           while (TREE_CHAIN (end))
5131             {
5132               end = TREE_CHAIN (end);
5133               sentinel = TREE_CHAIN (sentinel);
5134             }
5135
5136           /* Validate the sentinel.  */
5137           if (!POINTER_TYPE_P (TREE_TYPE (TREE_VALUE (sentinel)))
5138               || !integer_zerop (TREE_VALUE (sentinel)))
5139             warning ("missing sentinel in function call");
5140         }
5141     }
5142 }
5143
5144 /* Helper for check_function_nonnull; given a list of operands which
5145    must be non-null in ARGS, determine if operand PARAM_NUM should be
5146    checked.  */
5147
5148 static bool
5149 nonnull_check_p (tree args, unsigned HOST_WIDE_INT param_num)
5150 {
5151   unsigned HOST_WIDE_INT arg_num = 0;
5152
5153   for (; args; args = TREE_CHAIN (args))
5154     {
5155       bool found = get_nonnull_operand (TREE_VALUE (args), &arg_num);
5156
5157       gcc_assert (found);
5158
5159       if (arg_num == param_num)
5160         return true;
5161     }
5162   return false;
5163 }
5164
5165 /* Check that the function argument PARAM (which is operand number
5166    PARAM_NUM) is non-null.  This is called by check_function_nonnull
5167    via check_function_arguments_recurse.  */
5168
5169 static void
5170 check_nonnull_arg (void * ARG_UNUSED (ctx), tree param,
5171                    unsigned HOST_WIDE_INT param_num)
5172 {
5173   /* Just skip checking the argument if it's not a pointer.  This can
5174      happen if the "nonnull" attribute was given without an operand
5175      list (which means to check every pointer argument).  */
5176
5177   if (TREE_CODE (TREE_TYPE (param)) != POINTER_TYPE)
5178     return;
5179
5180   if (integer_zerop (param))
5181     warning ("null argument where non-null required (argument %lu)",
5182              (unsigned long) param_num);
5183 }
5184
5185 /* Helper for nonnull attribute handling; fetch the operand number
5186    from the attribute argument list.  */
5187
5188 static bool
5189 get_nonnull_operand (tree arg_num_expr, unsigned HOST_WIDE_INT *valp)
5190 {
5191   /* Verify the arg number is a constant.  */
5192   if (TREE_CODE (arg_num_expr) != INTEGER_CST
5193       || TREE_INT_CST_HIGH (arg_num_expr) != 0)
5194     return false;
5195
5196   *valp = TREE_INT_CST_LOW (arg_num_expr);
5197   return true;
5198 }
5199
5200 /* Handle a "nothrow" attribute; arguments as in
5201    struct attribute_spec.handler.  */
5202
5203 static tree
5204 handle_nothrow_attribute (tree *node, tree name, tree ARG_UNUSED (args),
5205                           int ARG_UNUSED (flags), bool *no_add_attrs)
5206 {
5207   if (TREE_CODE (*node) == FUNCTION_DECL)
5208     TREE_NOTHROW (*node) = 1;
5209   /* ??? TODO: Support types.  */
5210   else
5211     {
5212       warning ("%qE attribute ignored", name);
5213       *no_add_attrs = true;
5214     }
5215
5216   return NULL_TREE;
5217 }
5218
5219 /* Handle a "cleanup" attribute; arguments as in
5220    struct attribute_spec.handler.  */
5221
5222 static tree
5223 handle_cleanup_attribute (tree *node, tree name, tree args,
5224                           int ARG_UNUSED (flags), bool *no_add_attrs)
5225 {
5226   tree decl = *node;
5227   tree cleanup_id, cleanup_decl;
5228
5229   /* ??? Could perhaps support cleanups on TREE_STATIC, much like we do
5230      for global destructors in C++.  This requires infrastructure that
5231      we don't have generically at the moment.  It's also not a feature
5232      we'd be missing too much, since we do have attribute constructor.  */
5233   if (TREE_CODE (decl) != VAR_DECL || TREE_STATIC (decl))
5234     {
5235       warning ("%qE attribute ignored", name);
5236       *no_add_attrs = true;
5237       return NULL_TREE;
5238     }
5239
5240   /* Verify that the argument is a function in scope.  */
5241   /* ??? We could support pointers to functions here as well, if
5242      that was considered desirable.  */
5243   cleanup_id = TREE_VALUE (args);
5244   if (TREE_CODE (cleanup_id) != IDENTIFIER_NODE)
5245     {
5246       error ("cleanup argument not an identifier");
5247       *no_add_attrs = true;
5248       return NULL_TREE;
5249     }
5250   cleanup_decl = lookup_name (cleanup_id);
5251   if (!cleanup_decl || TREE_CODE (cleanup_decl) != FUNCTION_DECL)
5252     {
5253       error ("cleanup argument not a function");
5254       *no_add_attrs = true;
5255       return NULL_TREE;
5256     }
5257
5258   /* That the function has proper type is checked with the
5259      eventual call to build_function_call.  */
5260
5261   return NULL_TREE;
5262 }
5263
5264 /* Handle a "warn_unused_result" attribute.  No special handling.  */
5265
5266 static tree
5267 handle_warn_unused_result_attribute (tree *node, tree name,
5268                                tree ARG_UNUSED (args),
5269                                int ARG_UNUSED (flags), bool *no_add_attrs)
5270 {
5271   /* Ignore the attribute for functions not returning any value.  */
5272   if (VOID_TYPE_P (TREE_TYPE (*node)))
5273     {
5274       warning ("%qE attribute ignored", name);
5275       *no_add_attrs = true;
5276     }
5277
5278   return NULL_TREE;
5279 }
5280
5281 /* Handle a "sentinel" attribute.  */
5282
5283 static tree
5284 handle_sentinel_attribute (tree *node, tree name, tree args,
5285                            int ARG_UNUSED (flags), bool *no_add_attrs)
5286 {
5287   tree params = TYPE_ARG_TYPES (*node);
5288
5289   if (!params)
5290     {
5291       warning ("%qE attribute requires prototypes with named arguments", name);
5292       *no_add_attrs = true;
5293     }
5294   else
5295     {
5296       while (TREE_CHAIN (params))
5297         params = TREE_CHAIN (params);
5298
5299       if (VOID_TYPE_P (TREE_VALUE (params)))
5300         {
5301           warning ("%qE attribute only applies to variadic functions", name);
5302           *no_add_attrs = true;
5303         }
5304     }
5305
5306   if (args)
5307     {
5308       tree position = TREE_VALUE (args);
5309
5310       if (TREE_CODE (position) != INTEGER_CST)
5311         {
5312           warning ("requested position is not an integer constant");
5313           *no_add_attrs = true;
5314         }
5315       else
5316         {
5317           if (tree_int_cst_lt (position, integer_zero_node))
5318             {
5319               warning ("requested position is less than zero");
5320               *no_add_attrs = true;
5321             }
5322         }
5323     }
5324
5325   return NULL_TREE;
5326 }
5327 \f
5328 /* Check for valid arguments being passed to a function.  */
5329 void
5330 check_function_arguments (tree attrs, tree params)
5331 {
5332   /* Check for null being passed in a pointer argument that must be
5333      non-null.  We also need to do this if format checking is enabled.  */
5334
5335   if (warn_nonnull)
5336     check_function_nonnull (attrs, params);
5337
5338   /* Check for errors in format strings.  */
5339
5340   if (warn_format)
5341     {
5342       check_function_format (attrs, params);
5343       check_function_sentinel (attrs, params);
5344     }
5345 }
5346
5347 /* Generic argument checking recursion routine.  PARAM is the argument to
5348    be checked.  PARAM_NUM is the number of the argument.  CALLBACK is invoked
5349    once the argument is resolved.  CTX is context for the callback.  */
5350 void
5351 check_function_arguments_recurse (void (*callback)
5352                                   (void *, tree, unsigned HOST_WIDE_INT),
5353                                   void *ctx, tree param,
5354                                   unsigned HOST_WIDE_INT param_num)
5355 {
5356   if (TREE_CODE (param) == NOP_EXPR)
5357     {
5358       /* Strip coercion.  */
5359       check_function_arguments_recurse (callback, ctx,
5360                                         TREE_OPERAND (param, 0), param_num);
5361       return;
5362     }
5363
5364   if (TREE_CODE (param) == CALL_EXPR)
5365     {
5366       tree type = TREE_TYPE (TREE_TYPE (TREE_OPERAND (param, 0)));
5367       tree attrs;
5368       bool found_format_arg = false;
5369
5370       /* See if this is a call to a known internationalization function
5371          that modifies a format arg.  Such a function may have multiple
5372          format_arg attributes (for example, ngettext).  */
5373
5374       for (attrs = TYPE_ATTRIBUTES (type);
5375            attrs;
5376            attrs = TREE_CHAIN (attrs))
5377         if (is_attribute_p ("format_arg", TREE_PURPOSE (attrs)))
5378           {
5379             tree inner_args;
5380             tree format_num_expr;
5381             int format_num;
5382             int i;
5383
5384             /* Extract the argument number, which was previously checked
5385                to be valid.  */
5386             format_num_expr = TREE_VALUE (TREE_VALUE (attrs));
5387
5388             gcc_assert (TREE_CODE (format_num_expr) == INTEGER_CST
5389                         && !TREE_INT_CST_HIGH (format_num_expr));
5390
5391             format_num = TREE_INT_CST_LOW (format_num_expr);
5392
5393             for (inner_args = TREE_OPERAND (param, 1), i = 1;
5394                  inner_args != 0;
5395                  inner_args = TREE_CHAIN (inner_args), i++)
5396               if (i == format_num)
5397                 {
5398                   check_function_arguments_recurse (callback, ctx,
5399                                                     TREE_VALUE (inner_args),
5400                                                     param_num);
5401                   found_format_arg = true;
5402                   break;
5403                 }
5404           }
5405
5406       /* If we found a format_arg attribute and did a recursive check,
5407          we are done with checking this argument.  Otherwise, we continue
5408          and this will be considered a non-literal.  */
5409       if (found_format_arg)
5410         return;
5411     }
5412
5413   if (TREE_CODE (param) == COND_EXPR)
5414     {
5415       /* Check both halves of the conditional expression.  */
5416       check_function_arguments_recurse (callback, ctx,
5417                                         TREE_OPERAND (param, 1), param_num);
5418       check_function_arguments_recurse (callback, ctx,
5419                                         TREE_OPERAND (param, 2), param_num);
5420       return;
5421     }
5422
5423   (*callback) (ctx, param, param_num);
5424 }
5425
5426 /* Function to help qsort sort FIELD_DECLs by name order.  */
5427
5428 int
5429 field_decl_cmp (const void *x_p, const void *y_p)
5430 {
5431   const tree *const x = (const tree *const) x_p;
5432   const tree *const y = (const tree *const) y_p;
5433
5434   if (DECL_NAME (*x) == DECL_NAME (*y))
5435     /* A nontype is "greater" than a type.  */
5436     return (TREE_CODE (*y) == TYPE_DECL) - (TREE_CODE (*x) == TYPE_DECL);
5437   if (DECL_NAME (*x) == NULL_TREE)
5438     return -1;
5439   if (DECL_NAME (*y) == NULL_TREE)
5440     return 1;
5441   if (DECL_NAME (*x) < DECL_NAME (*y))
5442     return -1;
5443   return 1;
5444 }
5445
5446 static struct {
5447   gt_pointer_operator new_value;
5448   void *cookie;
5449 } resort_data;
5450
5451 /* This routine compares two fields like field_decl_cmp but using the
5452 pointer operator in resort_data.  */
5453
5454 static int
5455 resort_field_decl_cmp (const void *x_p, const void *y_p)
5456 {
5457   const tree *const x = (const tree *const) x_p;
5458   const tree *const y = (const tree *const) y_p;
5459
5460   if (DECL_NAME (*x) == DECL_NAME (*y))
5461     /* A nontype is "greater" than a type.  */
5462     return (TREE_CODE (*y) == TYPE_DECL) - (TREE_CODE (*x) == TYPE_DECL);
5463   if (DECL_NAME (*x) == NULL_TREE)
5464     return -1;
5465   if (DECL_NAME (*y) == NULL_TREE)
5466     return 1;
5467   {
5468     tree d1 = DECL_NAME (*x);
5469     tree d2 = DECL_NAME (*y);
5470     resort_data.new_value (&d1, resort_data.cookie);
5471     resort_data.new_value (&d2, resort_data.cookie);
5472     if (d1 < d2)
5473       return -1;
5474   }
5475   return 1;
5476 }
5477
5478 /* Resort DECL_SORTED_FIELDS because pointers have been reordered.  */
5479
5480 void
5481 resort_sorted_fields (void *obj,
5482                       void * ARG_UNUSED (orig_obj),
5483                       gt_pointer_operator new_value,
5484                       void *cookie)
5485 {
5486   struct sorted_fields_type *sf = (struct sorted_fields_type *) obj;
5487   resort_data.new_value = new_value;
5488   resort_data.cookie = cookie;
5489   qsort (&sf->elts[0], sf->len, sizeof (tree),
5490          resort_field_decl_cmp);
5491 }
5492
5493 /* Subroutine of c_parse_error.
5494    Return the result of concatenating LHS and RHS. RHS is really
5495    a string literal, its first character is indicated by RHS_START and
5496    RHS_SIZE is its length (including the terminating NUL character).
5497
5498    The caller is responsible for deleting the returned pointer.  */
5499
5500 static char *
5501 catenate_strings (const char *lhs, const char *rhs_start, int rhs_size)
5502 {
5503   const int lhs_size = strlen (lhs);
5504   char *result = XNEWVEC (char, lhs_size + rhs_size);
5505   strncpy (result, lhs, lhs_size);
5506   strncpy (result + lhs_size, rhs_start, rhs_size);
5507   return result;
5508 }
5509
5510 /* Issue the error given by MSGID, indicating that it occurred before
5511    TOKEN, which had the associated VALUE.  */
5512
5513 void
5514 c_parse_error (const char *msgid, enum cpp_ttype token, tree value)
5515 {
5516 #define catenate_messages(M1, M2) catenate_strings ((M1), (M2), sizeof (M2))
5517
5518   char *message = NULL;
5519
5520   if (token == CPP_EOF)
5521     message = catenate_messages (msgid, " at end of input");
5522   else if (token == CPP_CHAR || token == CPP_WCHAR)
5523     {
5524       unsigned int val = TREE_INT_CST_LOW (value);
5525       const char *const ell = (token == CPP_CHAR) ? "" : "L";
5526       if (val <= UCHAR_MAX && ISGRAPH (val))
5527         message = catenate_messages (msgid, " before %s'%c'");
5528       else
5529         message = catenate_messages (msgid, " before %s'\\x%x'");
5530
5531       error (message, ell, val);
5532       free (message);
5533       message = NULL;
5534     }
5535   else if (token == CPP_STRING || token == CPP_WSTRING)
5536     message = catenate_messages (msgid, " before string constant");
5537   else if (token == CPP_NUMBER)
5538     message = catenate_messages (msgid, " before numeric constant");
5539   else if (token == CPP_NAME)
5540     {
5541       message = catenate_messages (msgid, " before %qE");
5542       error (message, value);
5543       free (message);
5544       message = NULL;
5545     }
5546   else if (token < N_TTYPES)
5547     {
5548       message = catenate_messages (msgid, " before %qs token");
5549       error (message, cpp_type2name (token));
5550       free (message);
5551       message = NULL;
5552     }
5553   else
5554     error (msgid);
5555
5556   if (message)
5557     {
5558       error (message);
5559       free (message);
5560     }
5561 #undef catenate_messages
5562 }
5563
5564 /* Walk a gimplified function and warn for functions whose return value is
5565    ignored and attribute((warn_unused_result)) is set.  This is done before
5566    inlining, so we don't have to worry about that.  */
5567
5568 void
5569 c_warn_unused_result (tree *top_p)
5570 {
5571   tree t = *top_p;
5572   tree_stmt_iterator i;
5573   tree fdecl, ftype;
5574
5575   switch (TREE_CODE (t))
5576     {
5577     case STATEMENT_LIST:
5578       for (i = tsi_start (*top_p); !tsi_end_p (i); tsi_next (&i))
5579         c_warn_unused_result (tsi_stmt_ptr (i));
5580       break;
5581
5582     case COND_EXPR:
5583       c_warn_unused_result (&COND_EXPR_THEN (t));
5584       c_warn_unused_result (&COND_EXPR_ELSE (t));
5585       break;
5586     case BIND_EXPR:
5587       c_warn_unused_result (&BIND_EXPR_BODY (t));
5588       break;
5589     case TRY_FINALLY_EXPR:
5590     case TRY_CATCH_EXPR:
5591       c_warn_unused_result (&TREE_OPERAND (t, 0));
5592       c_warn_unused_result (&TREE_OPERAND (t, 1));
5593       break;
5594     case CATCH_EXPR:
5595       c_warn_unused_result (&CATCH_BODY (t));
5596       break;
5597     case EH_FILTER_EXPR:
5598       c_warn_unused_result (&EH_FILTER_FAILURE (t));
5599       break;
5600
5601     case CALL_EXPR:
5602       if (TREE_USED (t))
5603         break;
5604
5605       /* This is a naked call, as opposed to a CALL_EXPR nested inside
5606          a MODIFY_EXPR.  All calls whose value is ignored should be
5607          represented like this.  Look for the attribute.  */
5608       fdecl = get_callee_fndecl (t);
5609       if (fdecl)
5610         ftype = TREE_TYPE (fdecl);
5611       else
5612         {
5613           ftype = TREE_TYPE (TREE_OPERAND (t, 0));
5614           /* Look past pointer-to-function to the function type itself.  */
5615           ftype = TREE_TYPE (ftype);
5616         }
5617
5618       if (lookup_attribute ("warn_unused_result", TYPE_ATTRIBUTES (ftype)))
5619         {
5620           if (fdecl)
5621             warning ("%Hignoring return value of %qD, "
5622                      "declared with attribute warn_unused_result",
5623                      EXPR_LOCUS (t), fdecl);
5624           else
5625             warning ("%Hignoring return value of function "
5626                      "declared with attribute warn_unused_result",
5627                      EXPR_LOCUS (t));
5628         }
5629       break;
5630
5631     default:
5632       /* Not a container, not a call, or a call whose value is used.  */
5633       break;
5634     }
5635 }
5636
5637 /* Convert a character from the host to the target execution character
5638    set.  cpplib handles this, mostly.  */
5639
5640 HOST_WIDE_INT
5641 c_common_to_target_charset (HOST_WIDE_INT c)
5642 {
5643   /* Character constants in GCC proper are sign-extended under -fsigned-char,
5644      zero-extended under -fno-signed-char.  cpplib insists that characters
5645      and character constants are always unsigned.  Hence we must convert
5646      back and forth.  */
5647   cppchar_t uc = ((cppchar_t)c) & ((((cppchar_t)1) << CHAR_BIT)-1);
5648
5649   uc = cpp_host_to_exec_charset (parse_in, uc);
5650
5651   if (flag_signed_char)
5652     return ((HOST_WIDE_INT)uc) << (HOST_BITS_PER_WIDE_INT - CHAR_TYPE_SIZE)
5653                                >> (HOST_BITS_PER_WIDE_INT - CHAR_TYPE_SIZE);
5654   else
5655     return uc;
5656 }
5657
5658 /* Build the result of __builtin_offsetof.  EXPR is a nested sequence of
5659    component references, with an INDIRECT_REF at the bottom; much like
5660    the traditional rendering of offsetof as a macro.  Returns the folded
5661    and properly cast result.  */
5662
5663 static tree
5664 fold_offsetof_1 (tree expr)
5665 {
5666   enum tree_code code = PLUS_EXPR;
5667   tree base, off, t;
5668
5669   switch (TREE_CODE (expr))
5670     {
5671     case ERROR_MARK:
5672       return expr;
5673
5674     case INDIRECT_REF:
5675       return size_zero_node;
5676
5677     case COMPONENT_REF:
5678       base = fold_offsetof_1 (TREE_OPERAND (expr, 0));
5679       if (base == error_mark_node)
5680         return base;
5681
5682       t = TREE_OPERAND (expr, 1);
5683       if (DECL_C_BIT_FIELD (t))
5684         {
5685           error ("attempt to take address of bit-field structure "
5686                  "member %qD", t);
5687           return error_mark_node;
5688         }
5689       off = size_binop (PLUS_EXPR, DECL_FIELD_OFFSET (t),
5690                         size_int (tree_low_cst (DECL_FIELD_BIT_OFFSET (t), 1)
5691                                   / BITS_PER_UNIT));
5692       break;
5693
5694     case ARRAY_REF:
5695       base = fold_offsetof_1 (TREE_OPERAND (expr, 0));
5696       if (base == error_mark_node)
5697         return base;
5698
5699       t = TREE_OPERAND (expr, 1);
5700       if (TREE_CODE (t) == INTEGER_CST && tree_int_cst_sgn (t) < 0)
5701         {
5702           code = MINUS_EXPR;
5703           t = fold (build1 (NEGATE_EXPR, TREE_TYPE (t), t));
5704         }
5705       t = convert (sizetype, t);
5706       off = size_binop (MULT_EXPR, TYPE_SIZE_UNIT (TREE_TYPE (expr)), t);
5707       break;
5708
5709     default:
5710       gcc_unreachable ();
5711     }
5712
5713   return size_binop (code, base, off);
5714 }
5715
5716 tree
5717 fold_offsetof (tree expr)
5718 {
5719   /* Convert back from the internal sizetype to size_t.  */
5720   return convert (size_type_node, fold_offsetof_1 (expr));
5721 }
5722
5723 /* Print an error message for an invalid lvalue.  USE says
5724    how the lvalue is being used and so selects the error message.  */
5725
5726 void
5727 lvalue_error (enum lvalue_use use)
5728 {
5729   switch (use)
5730     {
5731     case lv_assign:
5732       error ("invalid lvalue in assignment");
5733       break;
5734     case lv_increment:
5735       error ("invalid lvalue in increment");
5736       break;
5737     case lv_decrement:
5738       error ("invalid lvalue in decrement");
5739       break;
5740     case lv_addressof:
5741       error ("invalid lvalue in unary %<&%>");
5742       break;
5743     case lv_asm:
5744       error ("invalid lvalue in asm statement");
5745       break;
5746     default:
5747       gcc_unreachable ();
5748     }
5749 }
5750 \f
5751 /* *PTYPE is an incomplete array.  Complete it with a domain based on
5752    INITIAL_VALUE.  If INITIAL_VALUE is not present, use 1 if DO_DEFAULT
5753    is true.  Return 0 if successful, 1 if INITIAL_VALUE can't be deciphered,
5754    2 if INITIAL_VALUE was NULL, and 3 if INITIAL_VALUE was empty.  */
5755
5756 int
5757 complete_array_type (tree *ptype, tree initial_value, bool do_default)
5758 {
5759   tree maxindex, type, main_type, elt, unqual_elt;
5760   int failure = 0, quals;
5761
5762   maxindex = size_zero_node;
5763   if (initial_value)
5764     {
5765       if (TREE_CODE (initial_value) == STRING_CST)
5766         {
5767           int eltsize
5768             = int_size_in_bytes (TREE_TYPE (TREE_TYPE (initial_value)));
5769           maxindex = size_int (TREE_STRING_LENGTH (initial_value)/eltsize - 1);
5770         }
5771       else if (TREE_CODE (initial_value) == CONSTRUCTOR)
5772         {
5773           tree elts = CONSTRUCTOR_ELTS (initial_value);
5774
5775           if (elts == NULL)
5776             {
5777               if (pedantic)
5778                 failure = 3;
5779               maxindex = integer_minus_one_node;
5780             }
5781           else
5782             {
5783               tree curindex;
5784
5785               if (TREE_PURPOSE (elts))
5786                 maxindex = fold_convert (sizetype, TREE_PURPOSE (elts));
5787               curindex = maxindex;
5788
5789               for (elts = TREE_CHAIN (elts); elts; elts = TREE_CHAIN (elts))
5790                 {
5791                   if (TREE_PURPOSE (elts))
5792                     curindex = fold_convert (sizetype, TREE_PURPOSE (elts));
5793                   else
5794                     curindex = size_binop (PLUS_EXPR, curindex, size_one_node);
5795
5796                   if (tree_int_cst_lt (maxindex, curindex))
5797                     maxindex = curindex;
5798                 }
5799             }
5800         }
5801       else
5802         {
5803           /* Make an error message unless that happened already.  */
5804           if (initial_value != error_mark_node)
5805             failure = 1;
5806         }
5807     }
5808   else
5809     {
5810       failure = 2;
5811       if (!do_default)
5812         return failure;
5813     }
5814
5815   type = *ptype;
5816   elt = TREE_TYPE (type);
5817   quals = TYPE_QUALS (strip_array_types (elt));
5818   if (quals == 0)
5819     unqual_elt = elt;
5820   else
5821     unqual_elt = c_build_qualified_type (elt, TYPE_UNQUALIFIED);
5822
5823   /* Using build_distinct_type_copy and modifying things afterward instead
5824      of using build_array_type to create a new type preserves all of the
5825      TYPE_LANG_FLAG_? bits that the front end may have set.  */
5826   main_type = build_distinct_type_copy (TYPE_MAIN_VARIANT (type));
5827   TREE_TYPE (main_type) = unqual_elt;
5828   TYPE_DOMAIN (main_type) = build_index_type (maxindex);
5829   layout_type (main_type);
5830
5831   if (quals == 0)
5832     type = main_type;
5833   else
5834     type = c_build_qualified_type (main_type, quals);
5835
5836   *ptype = type;
5837   return failure;
5838 }
5839
5840 \f
5841 /* Used to help initialize the builtin-types.def table.  When a type of
5842    the correct size doesn't exist, use error_mark_node instead of NULL.
5843    The later results in segfaults even when a decl using the type doesn't
5844    get invoked.  */
5845
5846 tree
5847 builtin_type_for_size (int size, bool unsignedp)
5848 {
5849   tree type = lang_hooks.types.type_for_size (size, unsignedp);
5850   return type ? type : error_mark_node;
5851 }
5852
5853 /* A helper function for resolve_overloaded_builtin in resolving the
5854    overloaded __sync_ builtins.  Returns a positive power of 2 if the
5855    first operand of PARAMS is a pointer to a supported data type.
5856    Returns 0 if an error is encountered.  */
5857
5858 static int
5859 sync_resolve_size (tree function, tree params)
5860 {
5861   tree type;
5862   int size;
5863
5864   if (params == NULL)
5865     {
5866       error ("too few arguments to function %qE", function);
5867       return 0;
5868     }
5869
5870   type = TREE_TYPE (TREE_VALUE (params));
5871   if (TREE_CODE (type) != POINTER_TYPE)
5872     goto incompatible;
5873
5874   type = TREE_TYPE (type);
5875   if (!INTEGRAL_TYPE_P (type) && !POINTER_TYPE_P (type))
5876     goto incompatible;
5877
5878   size = tree_low_cst (TYPE_SIZE_UNIT (type), 1);
5879   if (size == 1 || size == 2 || size == 4 || size == 8)
5880     return size;
5881
5882  incompatible:
5883   error ("incompatible type for argument %d of %qE", 1, function);
5884   return 0;
5885 }
5886
5887 /* A helper function for resolve_overloaded_builtin.  Adds casts to
5888    PARAMS to make arguments match up with those of FUNCTION.  Drops
5889    the variadic arguments at the end.  Returns false if some error
5890    was encountered; true on success.  */
5891
5892 static bool
5893 sync_resolve_params (tree orig_function, tree function, tree params)
5894 {
5895   tree arg_types = TYPE_ARG_TYPES (TREE_TYPE (function));
5896   tree ptype;
5897   int number;
5898
5899   /* We've declared the implementation functions to use "volatile void *"
5900      as the pointer parameter, so we shouldn't get any complaints from the
5901      call to check_function_arguments what ever type the user used.  */
5902   arg_types = TREE_CHAIN (arg_types);
5903   ptype = TREE_TYPE (TREE_TYPE (TREE_VALUE (params)));
5904   number = 2;
5905
5906   /* For the rest of the values, we need to cast these to FTYPE, so that we
5907      don't get warnings for passing pointer types, etc.  */
5908   while (arg_types != void_list_node)
5909     {
5910       tree val;
5911
5912       params = TREE_CHAIN (params);
5913       if (params == NULL)
5914         {
5915           error ("too few arguments to function %qE", orig_function);
5916           return false;
5917         }
5918
5919       /* ??? Ideally for the first conversion we'd use convert_for_assignment
5920          so that we get warnings for anything that doesn't match the pointer
5921          type.  This isn't portable across the C and C++ front ends atm.  */
5922       val = TREE_VALUE (params);
5923       val = convert (ptype, val);
5924       val = convert (TREE_VALUE (arg_types), val);
5925       TREE_VALUE (params) = val;
5926
5927       arg_types = TREE_CHAIN (arg_types);
5928       number++;
5929     }
5930
5931   /* The definition of these primitives is variadic, with the remaining
5932      being "an optional list of variables protected by the memory barrier".
5933      No clue what that's supposed to mean, precisely, but we consider all
5934      call-clobbered variables to be protected so we're safe.  */
5935   TREE_CHAIN (params) = NULL;
5936
5937   return true;
5938 }
5939
5940 /* A helper function for resolve_overloaded_builtin.  Adds a cast to
5941    RESULT to make it match the type of the first pointer argument in
5942    PARAMS.  */
5943
5944 static tree
5945 sync_resolve_return (tree params, tree result)
5946 {
5947   tree ptype = TREE_TYPE (TREE_TYPE (TREE_VALUE (params)));
5948   return convert (ptype, result);
5949 }
5950
5951 /* Some builtin functions are placeholders for other expressions.  This
5952    function should be called immediately after parsing the call expression
5953    before surrounding code has committed to the type of the expression.
5954
5955    FUNCTION is the DECL that has been invoked; it is known to be a builtin.
5956    PARAMS is the argument list for the call.  The return value is non-null
5957    when expansion is complete, and null if normal processing should
5958    continue.  */
5959
5960 tree
5961 resolve_overloaded_builtin (tree function, tree params)
5962 {
5963   enum built_in_function orig_code = DECL_FUNCTION_CODE (function);
5964   switch (orig_code)
5965     {
5966     case BUILT_IN_FETCH_AND_ADD_N:
5967     case BUILT_IN_FETCH_AND_SUB_N:
5968     case BUILT_IN_FETCH_AND_OR_N:
5969     case BUILT_IN_FETCH_AND_AND_N:
5970     case BUILT_IN_FETCH_AND_XOR_N:
5971     case BUILT_IN_FETCH_AND_NAND_N:
5972     case BUILT_IN_ADD_AND_FETCH_N:
5973     case BUILT_IN_SUB_AND_FETCH_N:
5974     case BUILT_IN_OR_AND_FETCH_N:
5975     case BUILT_IN_AND_AND_FETCH_N:
5976     case BUILT_IN_XOR_AND_FETCH_N:
5977     case BUILT_IN_NAND_AND_FETCH_N:
5978     case BUILT_IN_BOOL_COMPARE_AND_SWAP_N:
5979     case BUILT_IN_VAL_COMPARE_AND_SWAP_N:
5980     case BUILT_IN_LOCK_TEST_AND_SET_N:
5981     case BUILT_IN_LOCK_RELEASE_N:
5982       {
5983         int n = sync_resolve_size (function, params);
5984         tree new_function, result;
5985
5986         if (n == 0)
5987           return error_mark_node;
5988
5989         new_function = built_in_decls[orig_code + exact_log2 (n) + 1];
5990         if (!sync_resolve_params (function, new_function, params))
5991           return error_mark_node;
5992
5993         result = build_function_call (new_function, params);
5994         if (orig_code != BUILT_IN_BOOL_COMPARE_AND_SWAP_N
5995             && orig_code != BUILT_IN_LOCK_RELEASE_N)
5996           result = sync_resolve_return (params, result);
5997
5998         return result;
5999       }
6000
6001     default:
6002       return NULL;
6003     }
6004 }
6005
6006 #include "gt-c-common.h"