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 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
  50 cpp_reader *parse_in;           /* Declared in c-pragma.h.  */
  51
  52 /* We let tm.h override the types used here, to handle trivial differences
  53    such as the choice of unsigned int or long unsigned int for size_t.
  54    When machines start needing nontrivial differences in the size type,
  55    it would be best to do something here to figure out automatically
  56    from other information what type to use.  */
  57
  58 #ifndef SIZE_TYPE
  59 #define SIZE_TYPE "long unsigned int"
  60 #endif
  61
  62 #ifndef PID_TYPE
  63 #define PID_TYPE "int"
  64 #endif
  65
  66 #ifndef WCHAR_TYPE
  67 #define WCHAR_TYPE "int"
  68 #endif
  69
  70 /* WCHAR_TYPE gets overridden by -fshort-wchar.  */
  71 #define MODIFIED_WCHAR_TYPE \
  72         (flag_short_wchar ? "short unsigned int" : WCHAR_TYPE)
  73
  74 #ifndef PTRDIFF_TYPE
  75 #define PTRDIFF_TYPE "long int"
  76 #endif
  77
  78 #ifndef WINT_TYPE
  79 #define WINT_TYPE "unsigned int"
  80 #endif
  81
  82 #ifndef INTMAX_TYPE
  83 #define INTMAX_TYPE ((INT_TYPE_SIZE == LONG_LONG_TYPE_SIZE)     \
  84                      ? "int"                                    \
  85                      : ((LONG_TYPE_SIZE == LONG_LONG_TYPE_SIZE) \
  86                         ? "long int"                            \
  87                         : "long long int"))
  88 #endif
  89
  90 #ifndef UINTMAX_TYPE
  91 #define UINTMAX_TYPE ((INT_TYPE_SIZE == LONG_LONG_TYPE_SIZE)    \
  92                      ? "unsigned int"                           \
  93                      : ((LONG_TYPE_SIZE == LONG_LONG_TYPE_SIZE) \
  94                         ? "long unsigned int"                   \
  95                         : "long long unsigned int"))
  96 #endif
  97
  98 /* The following symbols are subsumed in the c_global_trees array, and
  99    listed here individually for documentation purposes.
 100
 101    INTEGER_TYPE and REAL_TYPE nodes for the standard data types.
 102
 103         tree short_integer_type_node;
 104         tree long_integer_type_node;
 105         tree long_long_integer_type_node;
 106
 107         tree short_unsigned_type_node;
 108         tree long_unsigned_type_node;
 109         tree long_long_unsigned_type_node;
 110
 111         tree truthvalue_type_node;
 112         tree truthvalue_false_node;
 113         tree truthvalue_true_node;
 114
 115         tree ptrdiff_type_node;
 116
 117         tree unsigned_char_type_node;
 118         tree signed_char_type_node;
 119         tree wchar_type_node;
 120         tree signed_wchar_type_node;
 121         tree unsigned_wchar_type_node;
 122
 123         tree float_type_node;
 124         tree double_type_node;
 125         tree long_double_type_node;
 126
 127         tree complex_integer_type_node;
 128         tree complex_float_type_node;
 129         tree complex_double_type_node;
 130         tree complex_long_double_type_node;
 131
 132         tree intQI_type_node;
 133         tree intHI_type_node;
 134         tree intSI_type_node;
 135         tree intDI_type_node;
 136         tree intTI_type_node;
 137
 138         tree unsigned_intQI_type_node;
 139         tree unsigned_intHI_type_node;
 140         tree unsigned_intSI_type_node;
 141         tree unsigned_intDI_type_node;
 142         tree unsigned_intTI_type_node;
 143
 144         tree widest_integer_literal_type_node;
 145         tree widest_unsigned_literal_type_node;
 146
 147    Nodes for types `void *' and `const void *'.
 148
 149         tree ptr_type_node, const_ptr_type_node;
 150
 151    Nodes for types `char *' and `const char *'.
 152
 153         tree string_type_node, const_string_type_node;
 154
 155    Type `char[SOMENUMBER]'.
 156    Used when an array of char is needed and the size is irrelevant.
 157
 158         tree char_array_type_node;
 159
 160    Type `int[SOMENUMBER]' or something like it.
 161    Used when an array of int needed and the size is irrelevant.
 162
 163         tree int_array_type_node;
 164
 165    Type `wchar_t[SOMENUMBER]' or something like it.
 166    Used when a wide string literal is created.
 167
 168         tree wchar_array_type_node;
 169
 170    Type `int ()' -- used for implicit declaration of functions.
 171
 172         tree default_function_type;
 173
 174    A VOID_TYPE node, packaged in a TREE_LIST.
 175
 176         tree void_list_node;
 177
 178   The lazily created VAR_DECLs for __FUNCTION__, __PRETTY_FUNCTION__,
 179   and __func__. (C doesn't generate __FUNCTION__ and__PRETTY_FUNCTION__
 180   VAR_DECLS, but C++ does.)
 181
 182         tree function_name_decl_node;
 183         tree pretty_function_name_decl_node;
 184         tree c99_function_name_decl_node;
 185
 186   Stack of nested function name VAR_DECLs.
 187
 188         tree saved_function_name_decls;
 189
 190 */
 191
 192 tree c_global_trees[CTI_MAX];
 193
 194 /* TRUE if a code represents a statement.  The front end init
 195    langhook should take care of initialization of this array.  */
 196
 197 bool statement_code_p[MAX_TREE_CODES];
 198 \f
 199 /* Switches common to the C front ends.  */
 200
 201 /* Nonzero if prepreprocessing only.  */
 202
 203 int flag_preprocess_only;
 204
 205 /* Nonzero means don't output line number information.  */
 206
 207 char flag_no_line_commands;
 208
 209 /* Nonzero causes -E output not to be done, but directives such as
 210    #define that have side effects are still obeyed.  */
 211
 212 char flag_no_output;
 213
 214 /* Nonzero means dump macros in some fashion.  */
 215
 216 char flag_dump_macros;
 217
 218 /* Nonzero means pass #include lines through to the output.  */
 219
 220 char flag_dump_includes;
 221
 222 /* Nonzero means process PCH files while preprocessing.  */
 223
 224 bool flag_pch_preprocess;
 225
 226 /* The file name to which we should write a precompiled header, or
 227    NULL if no header will be written in this compile.  */
 228
 229 const char *pch_file;
 230
 231 /* Nonzero if an ISO standard was selected.  It rejects macros in the
 232    user's namespace.  */
 233 int flag_iso;
 234
 235 /* Nonzero if -undef was given.  It suppresses target built-in macros
 236    and assertions.  */
 237 int flag_undef;
 238
 239 /* Nonzero means don't recognize the non-ANSI builtin functions.  */
 240
 241 int flag_no_builtin;
 242
 243 /* Nonzero means don't recognize the non-ANSI builtin functions.
 244    -ansi sets this.  */
 245
 246 int flag_no_nonansi_builtin;
 247
 248 /* Nonzero means give `double' the same size as `float'.  */
 249
 250 int flag_short_double;
 251
 252 /* Nonzero means give `wchar_t' the same size as `short'.  */
 253
 254 int flag_short_wchar;
 255
 256 /* Nonzero means allow Microsoft extensions without warnings or errors.  */
 257 int flag_ms_extensions;
 258
 259 /* Nonzero means don't recognize the keyword `asm'.  */
 260
 261 int flag_no_asm;
 262
 263 /* Nonzero means give string constants the type `const char *', as mandated
 264    by the standard.  */
 265
 266 int flag_const_strings;
 267
 268 /* Nonzero means to treat bitfields as signed unless they say `unsigned'.  */
 269
 270 int flag_signed_bitfields = 1;
 271 int explicit_flag_signed_bitfields;
 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 /* If non-NULL, the address of a language-specific function that
 486    returns 1 for language-specific statement codes.  */
 487 int (*lang_statement_code_p) (enum tree_code);
 488
 489 /* If non-NULL, the address of a language-specific function that takes
 490    any action required right before expand_function_end is called.  */
 491 void (*lang_expand_function_end) (void);
 492
 493 /* Nonzero means the expression being parsed will never be evaluated.
 494    This is a count, since unevaluated expressions can nest.  */
 495 int skip_evaluation;
 496
 497 /* Information about how a function name is generated.  */
 498 struct fname_var_t
 499 {
 500   tree *const decl;     /* pointer to the VAR_DECL.  */
 501   const unsigned rid;   /* RID number for the identifier.  */
 502   const int pretty;     /* How pretty is it? */
 503 };
 504
 505 /* The three ways of getting then name of the current function.  */
 506
 507 const struct fname_var_t fname_vars[] =
 508 {
 509   /* C99 compliant __func__, must be first.  */
 510   {&c99_function_name_decl_node, RID_C99_FUNCTION_NAME, 0},
 511   /* GCC __FUNCTION__ compliant.  */
 512   {&function_name_decl_node, RID_FUNCTION_NAME, 0},
 513   /* GCC __PRETTY_FUNCTION__ compliant.  */
 514   {&pretty_function_name_decl_node, RID_PRETTY_FUNCTION_NAME, 1},
 515   {NULL, 0, 0},
 516 };
 517
 518 static int constant_fits_type_p (tree, tree);
 519 static tree check_case_value (tree);
 520 static bool check_case_bounds (tree, tree, tree *, tree *);
 521
 522 static tree handle_packed_attribute (tree *, tree, tree, int, bool *);
 523 static tree handle_nocommon_attribute (tree *, tree, tree, int, bool *);
 524 static tree handle_common_attribute (tree *, tree, tree, int, bool *);
 525 static tree handle_noreturn_attribute (tree *, tree, tree, int, bool *);
 526 static tree handle_noinline_attribute (tree *, tree, tree, int, bool *);
 527 static tree handle_always_inline_attribute (tree *, tree, tree, int,
 528                                             bool *);
 529 static tree handle_used_attribute (tree *, tree, tree, int, bool *);
 530 static tree handle_unused_attribute (tree *, tree, tree, int, bool *);
 531 static tree handle_const_attribute (tree *, tree, tree, int, bool *);
 532 static tree handle_transparent_union_attribute (tree *, tree, tree,
 533                                                 int, bool *);
 534 static tree handle_constructor_attribute (tree *, tree, tree, int, bool *);
 535 static tree handle_destructor_attribute (tree *, tree, tree, int, bool *);
 536 static tree handle_mode_attribute (tree *, tree, tree, int, bool *);
 537 static tree handle_section_attribute (tree *, tree, tree, int, bool *);
 538 static tree handle_aligned_attribute (tree *, tree, tree, int, bool *);
 539 static tree handle_weak_attribute (tree *, tree, tree, int, bool *) ;
 540 static tree handle_alias_attribute (tree *, tree, tree, int, bool *);
 541 static tree handle_visibility_attribute (tree *, tree, tree, int,
 542                                          bool *);
 543 static tree handle_tls_model_attribute (tree *, tree, tree, int,
 544                                         bool *);
 545 static tree handle_no_instrument_function_attribute (tree *, tree,
 546                                                      tree, int, bool *);
 547 static tree handle_malloc_attribute (tree *, tree, tree, int, bool *);
 548 static tree handle_no_limit_stack_attribute (tree *, tree, tree, int,
 549                                              bool *);
 550 static tree handle_pure_attribute (tree *, tree, tree, int, bool *);
 551 static tree handle_deprecated_attribute (tree *, tree, tree, int,
 552                                          bool *);
 553 static tree handle_vector_size_attribute (tree *, tree, tree, int,
 554                                           bool *);
 555 static tree handle_nonnull_attribute (tree *, tree, tree, int, bool *);
 556 static tree handle_nothrow_attribute (tree *, tree, tree, int, bool *);
 557 static tree handle_cleanup_attribute (tree *, tree, tree, int, bool *);
 558 static tree handle_warn_unused_result_attribute (tree *, tree, tree, int,
 559                                                  bool *);
 560 static tree handle_sentinel_attribute (tree *, tree, tree, int, bool *);
 561
 562 static void check_function_nonnull (tree, tree);
 563 static void check_nonnull_arg (void *, tree, unsigned HOST_WIDE_INT);
 564 static bool nonnull_check_p (tree, unsigned HOST_WIDE_INT);
 565 static bool get_nonnull_operand (tree, unsigned HOST_WIDE_INT *);
 566 static int resort_field_decl_cmp (const void *, const void *);
 567
 568 /* Table of machine-independent attributes common to all C-like languages.  */
 569 const struct attribute_spec c_common_attribute_table[] =
 570 {
 571   /* { name, min_len, max_len, decl_req, type_req, fn_type_req, handler } */
 572   { "packed",                 0, 0, false, false, false,
 573                               handle_packed_attribute },
 574   { "nocommon",               0, 0, true,  false, false,
 575                               handle_nocommon_attribute },
 576   { "common",                 0, 0, true,  false, false,
 577                               handle_common_attribute },
 578   /* FIXME: logically, noreturn attributes should be listed as
 579      "false, true, true" and apply to function types.  But implementing this
 580      would require all the places in the compiler that use TREE_THIS_VOLATILE
 581      on a decl to identify non-returning functions to be located and fixed
 582      to check the function type instead.  */
 583   { "noreturn",               0, 0, true,  false, false,
 584                               handle_noreturn_attribute },
 585   { "volatile",               0, 0, true,  false, false,
 586                               handle_noreturn_attribute },
 587   { "noinline",               0, 0, true,  false, false,
 588                               handle_noinline_attribute },
 589   { "always_inline",          0, 0, true,  false, false,
 590                               handle_always_inline_attribute },
 591   { "used",                   0, 0, true,  false, false,
 592                               handle_used_attribute },
 593   { "unused",                 0, 0, false, false, false,
 594                               handle_unused_attribute },
 595   /* The same comments as for noreturn attributes apply to const ones.  */
 596   { "const",                  0, 0, true,  false, false,
 597                               handle_const_attribute },
 598   { "transparent_union",      0, 0, false, false, false,
 599                               handle_transparent_union_attribute },
 600   { "constructor",            0, 0, true,  false, false,
 601                               handle_constructor_attribute },
 602   { "destructor",             0, 0, true,  false, false,
 603                               handle_destructor_attribute },
 604   { "mode",                   1, 1, false,  true, false,
 605                               handle_mode_attribute },
 606   { "section",                1, 1, true,  false, false,
 607                               handle_section_attribute },
 608   { "aligned",                0, 1, false, false, false,
 609                               handle_aligned_attribute },
 610   { "weak",                   0, 0, true,  false, false,
 611                               handle_weak_attribute },
 612   { "alias",                  1, 1, true,  false, false,
 613                               handle_alias_attribute },
 614   { "no_instrument_function", 0, 0, true,  false, false,
 615                               handle_no_instrument_function_attribute },
 616   { "malloc",                 0, 0, true,  false, false,
 617                               handle_malloc_attribute },
 618   { "no_stack_limit",         0, 0, true,  false, false,
 619                               handle_no_limit_stack_attribute },
 620   { "pure",                   0, 0, true,  false, false,
 621                               handle_pure_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         return (char *) cstr.text;
 759     }
 760   else
 761     namep = xstrdup (name);
 762
 763   return namep;
 764 }
 765
 766 /* Expand DECL if it declares an entity not handled by the
 767    common code.  */
 768
 769 int
 770 c_expand_decl (tree decl)
 771 {
 772   if (TREE_CODE (decl) == VAR_DECL && !TREE_STATIC (decl))
 773     {
 774       /* Let the back-end know about this variable.  */
 775       if (!anon_aggr_type_p (TREE_TYPE (decl)))
 776         emit_local_var (decl);
 777       else
 778         expand_anon_union_decl (decl, NULL_TREE,
 779                                 DECL_ANON_UNION_ELEMS (decl));
 780     }
 781   else
 782     return 0;
 783
 784   return 1;
 785 }
 786
 787
 788 /* Return the VAR_DECL for a const char array naming the current
 789    function. If the VAR_DECL has not yet been created, create it
 790    now. RID indicates how it should be formatted and IDENTIFIER_NODE
 791    ID is its name (unfortunately C and C++ hold the RID values of
 792    keywords in different places, so we can't derive RID from ID in
 793    this language independent code.  */
 794
 795 tree
 796 fname_decl (unsigned int rid, tree id)
 797 {
 798   unsigned ix;
 799   tree decl = NULL_TREE;
 800
 801   for (ix = 0; fname_vars[ix].decl; ix++)
 802     if (fname_vars[ix].rid == rid)
 803       break;
 804
 805   decl = *fname_vars[ix].decl;
 806   if (!decl)
 807     {
 808       /* If a tree is built here, it would normally have the lineno of
 809          the current statement.  Later this tree will be moved to the
 810          beginning of the function and this line number will be wrong.
 811          To avoid this problem set the lineno to 0 here; that prevents
 812          it from appearing in the RTL.  */
 813       tree stmts;
 814       location_t saved_location = input_location;
 815 #ifdef USE_MAPPED_LOCATION
 816       input_location = UNKNOWN_LOCATION;
 817 #else
 818       input_line = 0;
 819 #endif
 820
 821       stmts = push_stmt_list ();
 822       decl = (*make_fname_decl) (id, fname_vars[ix].pretty);
 823       stmts = pop_stmt_list (stmts);
 824       if (!IS_EMPTY_STMT (stmts))
 825         saved_function_name_decls
 826           = tree_cons (decl, stmts, saved_function_name_decls);
 827       *fname_vars[ix].decl = decl;
 828       input_location = saved_location;
 829     }
 830   if (!ix && !current_function_decl)
 831     pedwarn ("%qD is not defined outside of function scope", decl);
 832
 833   return decl;
 834 }
 835
 836 /* Given a STRING_CST, give it a suitable array-of-chars data type.  */
 837
 838 tree
 839 fix_string_type (tree value)
 840 {
 841   const int wchar_bytes = TYPE_PRECISION (wchar_type_node) / BITS_PER_UNIT;
 842   const int wide_flag = TREE_TYPE (value) == wchar_array_type_node;
 843   const int nchars_max = flag_isoc99 ? 4095 : 509;
 844   int length = TREE_STRING_LENGTH (value);
 845   int nchars;
 846   tree e_type, i_type, a_type;
 847
 848   /* Compute the number of elements, for the array type.  */
 849   nchars = wide_flag ? length / wchar_bytes : length;
 850
 851   if (pedantic && nchars - 1 > nchars_max && !c_dialect_cxx ())
 852     pedwarn ("string length %qd is greater than the length %qd ISO C%d compilers are required to support",
 853              nchars - 1, nchars_max, flag_isoc99 ? 99 : 89);
 854
 855   e_type = wide_flag ? wchar_type_node : char_type_node;
 856   /* Create the array type for the string constant.  flag_const_strings
 857      says make the string constant an array of const char so that
 858      copying it to a non-const pointer will get a warning.  For C++,
 859      this is the standard behavior.
 860
 861      The C++ front end relies on TYPE_MAIN_VARIANT of a cv-qualified
 862      array type being the unqualified version of that type.
 863      Therefore, if we are constructing an array of const char, we must
 864      construct the matching unqualified array type first.  The C front
 865      end does not require this, but it does no harm, so we do it
 866      unconditionally.  */
 867   i_type = build_index_type (build_int_cst (NULL_TREE, nchars - 1));
 868   a_type = build_array_type (e_type, i_type);
 869   if (flag_const_strings)
 870     {
 871       /* bleah, c_build_qualified_type should set TYPE_MAIN_VARIANT.  */
 872       tree qa_type = c_build_qualified_type (a_type, TYPE_QUAL_CONST);
 873       TYPE_MAIN_VARIANT (qa_type) = a_type;
 874       a_type = qa_type;
 875     }
 876
 877   TREE_TYPE (value) = a_type;
 878   TREE_CONSTANT (value) = 1;
 879   TREE_INVARIANT (value) = 1;
 880   TREE_READONLY (value) = 1;
 881   TREE_STATIC (value) = 1;
 882   return value;
 883 }
 884 \f
 885 /* Print a warning if a constant expression had overflow in folding.
 886    Invoke this function on every expression that the language
 887    requires to be a constant expression.
 888    Note the ANSI C standard says it is erroneous for a
 889    constant expression to overflow.  */
 890
 891 void
 892 constant_expression_warning (tree value)
 893 {
 894   if ((TREE_CODE (value) == INTEGER_CST || TREE_CODE (value) == REAL_CST
 895        || TREE_CODE (value) == VECTOR_CST
 896        || TREE_CODE (value) == COMPLEX_CST)
 897       && TREE_CONSTANT_OVERFLOW (value) && pedantic)
 898     pedwarn ("overflow in constant expression");
 899 }
 900
 901 /* Print a warning if an expression had overflow in folding.
 902    Invoke this function on every expression that
 903    (1) appears in the source code, and
 904    (2) might be a constant expression that overflowed, and
 905    (3) is not already checked by convert_and_check;
 906    however, do not invoke this function on operands of explicit casts.  */
 907
 908 void
 909 overflow_warning (tree value)
 910 {
 911   if ((TREE_CODE (value) == INTEGER_CST
 912        || (TREE_CODE (value) == COMPLEX_CST
 913            && TREE_CODE (TREE_REALPART (value)) == INTEGER_CST))
 914       && TREE_OVERFLOW (value))
 915     {
 916       TREE_OVERFLOW (value) = 0;
 917       if (skip_evaluation == 0)
 918         warning ("integer overflow in expression");
 919     }
 920   else if ((TREE_CODE (value) == REAL_CST
 921             || (TREE_CODE (value) == COMPLEX_CST
 922                 && TREE_CODE (TREE_REALPART (value)) == REAL_CST))
 923            && TREE_OVERFLOW (value))
 924     {
 925       TREE_OVERFLOW (value) = 0;
 926       if (skip_evaluation == 0)
 927         warning ("floating point overflow in expression");
 928     }
 929   else if (TREE_CODE (value) == VECTOR_CST && TREE_OVERFLOW (value))
 930     {
 931       TREE_OVERFLOW (value) = 0;
 932       if (skip_evaluation == 0)
 933         warning ("vector overflow in expression");
 934     }
 935 }
 936
 937 /* Print a warning if a large constant is truncated to unsigned,
 938    or if -Wconversion is used and a constant < 0 is converted to unsigned.
 939    Invoke this function on every expression that might be implicitly
 940    converted to an unsigned type.  */
 941
 942 void
 943 unsigned_conversion_warning (tree result, tree operand)
 944 {
 945   tree type = TREE_TYPE (result);
 946
 947   if (TREE_CODE (operand) == INTEGER_CST
 948       && TREE_CODE (type) == INTEGER_TYPE
 949       && TYPE_UNSIGNED (type)
 950       && skip_evaluation == 0
 951       && !int_fits_type_p (operand, type))
 952     {
 953       if (!int_fits_type_p (operand, c_common_signed_type (type)))
 954         /* This detects cases like converting -129 or 256 to unsigned char.  */
 955         warning ("large integer implicitly truncated to unsigned type");
 956       else if (warn_conversion)
 957         warning ("negative integer implicitly converted to unsigned type");
 958     }
 959 }
 960
 961 /* Nonzero if constant C has a value that is permissible
 962    for type TYPE (an INTEGER_TYPE).  */
 963
 964 static int
 965 constant_fits_type_p (tree c, tree type)
 966 {
 967   if (TREE_CODE (c) == INTEGER_CST)
 968     return int_fits_type_p (c, type);
 969
 970   c = convert (type, c);
 971   return !TREE_OVERFLOW (c);
 972 }
 973
 974 /* Nonzero if vector types T1 and T2 can be converted to each other
 975    without an explicit cast.  */
 976 int
 977 vector_types_convertible_p (tree t1, tree t2)
 978 {
 979   return targetm.vector_opaque_p (t1)
 980          || targetm.vector_opaque_p (t2)
 981          || (tree_int_cst_equal (TYPE_SIZE (t1), TYPE_SIZE (t2))
 982              && INTEGRAL_TYPE_P (TREE_TYPE (t1))
 983                 == INTEGRAL_TYPE_P (TREE_TYPE (t2)));
 984 }
 985
 986 /* Convert EXPR to TYPE, warning about conversion problems with constants.
 987    Invoke this function on every expression that is converted implicitly,
 988    i.e. because of language rules and not because of an explicit cast.  */
 989
 990 tree
 991 convert_and_check (tree type, tree expr)
 992 {
 993   tree t = convert (type, expr);
 994   if (TREE_CODE (t) == INTEGER_CST)
 995     {
 996       if (TREE_OVERFLOW (t))
 997         {
 998           TREE_OVERFLOW (t) = 0;
 999
1000           /* Do not diagnose overflow in a constant expression merely
1001              because a conversion overflowed.  */
1002           TREE_CONSTANT_OVERFLOW (t) = TREE_CONSTANT_OVERFLOW (expr);
1003
1004           /* No warning for converting 0x80000000 to int.  */
1005           if (!(TYPE_UNSIGNED (type) < TYPE_UNSIGNED (TREE_TYPE (expr))
1006                 && TREE_CODE (TREE_TYPE (expr)) == INTEGER_TYPE
1007                 && TYPE_PRECISION (type) == TYPE_PRECISION (TREE_TYPE (expr))))
1008             /* If EXPR fits in the unsigned version of TYPE,
1009                don't warn unless pedantic.  */
1010             if ((pedantic
1011                  || TYPE_UNSIGNED (type)
1012                  || !constant_fits_type_p (expr,
1013                                            c_common_unsigned_type (type)))
1014                 && skip_evaluation == 0)
1015               warning ("overflow in implicit constant conversion");
1016         }
1017       else
1018         unsigned_conversion_warning (t, expr);
1019     }
1020   return t;
1021 }
1022 \f
1023 /* A node in a list that describes references to variables (EXPR), which are
1024    either read accesses if WRITER is zero, or write accesses, in which case
1025    WRITER is the parent of EXPR.  */
1026 struct tlist
1027 {
1028   struct tlist *next;
1029   tree expr, writer;
1030 };
1031
1032 /* Used to implement a cache the results of a call to verify_tree.  We only
1033    use this for SAVE_EXPRs.  */
1034 struct tlist_cache
1035 {
1036   struct tlist_cache *next;
1037   struct tlist *cache_before_sp;
1038   struct tlist *cache_after_sp;
1039   tree expr;
1040 };
1041
1042 /* Obstack to use when allocating tlist structures, and corresponding
1043    firstobj.  */
1044 static struct obstack tlist_obstack;
1045 static char *tlist_firstobj = 0;
1046
1047 /* Keep track of the identifiers we've warned about, so we can avoid duplicate
1048    warnings.  */
1049 static struct tlist *warned_ids;
1050 /* SAVE_EXPRs need special treatment.  We process them only once and then
1051    cache the results.  */
1052 static struct tlist_cache *save_expr_cache;
1053
1054 static void add_tlist (struct tlist **, struct tlist *, tree, int);
1055 static void merge_tlist (struct tlist **, struct tlist *, int);
1056 static void verify_tree (tree, struct tlist **, struct tlist **, tree);
1057 static int warning_candidate_p (tree);
1058 static void warn_for_collisions (struct tlist *);
1059 static void warn_for_collisions_1 (tree, tree, struct tlist *, int);
1060 static struct tlist *new_tlist (struct tlist *, tree, tree);
1061
1062 /* Create a new struct tlist and fill in its fields.  */
1063 static struct tlist *
1064 new_tlist (struct tlist *next, tree t, tree writer)
1065 {
1066   struct tlist *l;
1067   l = XOBNEW (&tlist_obstack, struct tlist);
1068   l->next = next;
1069   l->expr = t;
1070   l->writer = writer;
1071   return l;
1072 }
1073
1074 /* Add duplicates of the nodes found in ADD to the list *TO.  If EXCLUDE_WRITER
1075    is nonnull, we ignore any node we find which has a writer equal to it.  */
1076
1077 static void
1078 add_tlist (struct tlist **to, struct tlist *add, tree exclude_writer, int copy)
1079 {
1080   while (add)
1081     {
1082       struct tlist *next = add->next;
1083       if (!copy)
1084         add->next = *to;
1085       if (!exclude_writer || add->writer != exclude_writer)
1086         *to = copy ? new_tlist (*to, add->expr, add->writer) : add;
1087       add = next;
1088     }
1089 }
1090
1091 /* Merge the nodes of ADD into TO.  This merging process is done so that for
1092    each variable that already exists in TO, no new node is added; however if
1093    there is a write access recorded in ADD, and an occurrence on TO is only
1094    a read access, then the occurrence in TO will be modified to record the
1095    write.  */
1096
1097 static void
1098 merge_tlist (struct tlist **to, struct tlist *add, int copy)
1099 {
1100   struct tlist **end = to;
1101
1102   while (*end)
1103     end = &(*end)->next;
1104
1105   while (add)
1106     {
1107       int found = 0;
1108       struct tlist *tmp2;
1109       struct tlist *next = add->next;
1110
1111       for (tmp2 = *to; tmp2; tmp2 = tmp2->next)
1112         if (tmp2->expr == add->expr)
1113           {
1114             found = 1;
1115             if (!tmp2->writer)
1116               tmp2->writer = add->writer;
1117           }
1118       if (!found)
1119         {
1120           *end = copy ? add : new_tlist (NULL, add->expr, add->writer);
1121           end = &(*end)->next;
1122           *end = 0;
1123         }
1124       add = next;
1125     }
1126 }
1127
1128 /* WRITTEN is a variable, WRITER is its parent.  Warn if any of the variable
1129    references in list LIST conflict with it, excluding reads if ONLY writers
1130    is nonzero.  */
1131
1132 static void
1133 warn_for_collisions_1 (tree written, tree writer, struct tlist *list,
1134                        int only_writes)
1135 {
1136   struct tlist *tmp;
1137
1138   /* Avoid duplicate warnings.  */
1139   for (tmp = warned_ids; tmp; tmp = tmp->next)
1140     if (tmp->expr == written)
1141       return;
1142
1143   while (list)
1144     {
1145       if (list->expr == written
1146           && list->writer != writer
1147           && (!only_writes || list->writer)
1148           && DECL_NAME (list->expr))
1149         {
1150           warned_ids = new_tlist (warned_ids, written, NULL_TREE);
1151           warning ("operation on %qs may be undefined",
1152                    IDENTIFIER_POINTER (DECL_NAME (list->expr)));
1153         }
1154       list = list->next;
1155     }
1156 }
1157
1158 /* Given a list LIST of references to variables, find whether any of these
1159    can cause conflicts due to missing sequence points.  */
1160
1161 static void
1162 warn_for_collisions (struct tlist *list)
1163 {
1164   struct tlist *tmp;
1165
1166   for (tmp = list; tmp; tmp = tmp->next)
1167     {
1168       if (tmp->writer)
1169         warn_for_collisions_1 (tmp->expr, tmp->writer, list, 0);
1170     }
1171 }
1172
1173 /* Return nonzero if X is a tree that can be verified by the sequence point
1174    warnings.  */
1175 static int
1176 warning_candidate_p (tree x)
1177 {
1178   return TREE_CODE (x) == VAR_DECL || TREE_CODE (x) == PARM_DECL;
1179 }
1180
1181 /* Walk the tree X, and record accesses to variables.  If X is written by the
1182    parent tree, WRITER is the parent.
1183    We store accesses in one of the two lists: PBEFORE_SP, and PNO_SP.  If this
1184    expression or its only operand forces a sequence point, then everything up
1185    to the sequence point is stored in PBEFORE_SP.  Everything else gets stored
1186    in PNO_SP.
1187    Once we return, we will have emitted warnings if any subexpression before
1188    such a sequence point could be undefined.  On a higher level, however, the
1189    sequence point may not be relevant, and we'll merge the two lists.
1190
1191    Example: (b++, a) + b;
1192    The call that processes the COMPOUND_EXPR will store the increment of B
1193    in PBEFORE_SP, and the use of A in PNO_SP.  The higher-level call that
1194    processes the PLUS_EXPR will need to merge the two lists so that
1195    eventually, all accesses end up on the same list (and we'll warn about the
1196    unordered subexpressions b++ and b.
1197
1198    A note on merging.  If we modify the former example so that our expression
1199    becomes
1200      (b++, b) + a
1201    care must be taken not simply to add all three expressions into the final
1202    PNO_SP list.  The function merge_tlist takes care of that by merging the
1203    before-SP list of the COMPOUND_EXPR into its after-SP list in a special
1204    way, so that no more than one access to B is recorded.  */
1205
1206 static void
1207 verify_tree (tree x, struct tlist **pbefore_sp, struct tlist **pno_sp,
1208              tree writer)
1209 {
1210   struct tlist *tmp_before, *tmp_nosp, *tmp_list2, *tmp_list3;
1211   enum tree_code code;
1212   enum tree_code_class cl;
1213
1214   /* X may be NULL if it is the operand of an empty statement expression
1215      ({ }).  */
1216   if (x == NULL)
1217     return;
1218
1219  restart:
1220   code = TREE_CODE (x);
1221   cl = TREE_CODE_CLASS (code);
1222
1223   if (warning_candidate_p (x))
1224     {
1225       *pno_sp = new_tlist (*pno_sp, x, writer);
1226       return;
1227     }
1228
1229   switch (code)
1230     {
1231     case CONSTRUCTOR:
1232       return;
1233
1234     case COMPOUND_EXPR:
1235     case TRUTH_ANDIF_EXPR:
1236     case TRUTH_ORIF_EXPR:
1237       tmp_before = tmp_nosp = tmp_list3 = 0;
1238       verify_tree (TREE_OPERAND (x, 0), &tmp_before, &tmp_nosp, NULL_TREE);
1239       warn_for_collisions (tmp_nosp);
1240       merge_tlist (pbefore_sp, tmp_before, 0);
1241       merge_tlist (pbefore_sp, tmp_nosp, 0);
1242       verify_tree (TREE_OPERAND (x, 1), &tmp_list3, pno_sp, NULL_TREE);
1243       merge_tlist (pbefore_sp, tmp_list3, 0);
1244       return;
1245
1246     case COND_EXPR:
1247       tmp_before = tmp_list2 = 0;
1248       verify_tree (TREE_OPERAND (x, 0), &tmp_before, &tmp_list2, NULL_TREE);
1249       warn_for_collisions (tmp_list2);
1250       merge_tlist (pbefore_sp, tmp_before, 0);
1251       merge_tlist (pbefore_sp, tmp_list2, 1);
1252
1253       tmp_list3 = tmp_nosp = 0;
1254       verify_tree (TREE_OPERAND (x, 1), &tmp_list3, &tmp_nosp, NULL_TREE);
1255       warn_for_collisions (tmp_nosp);
1256       merge_tlist (pbefore_sp, tmp_list3, 0);
1257
1258       tmp_list3 = tmp_list2 = 0;
1259       verify_tree (TREE_OPERAND (x, 2), &tmp_list3, &tmp_list2, NULL_TREE);
1260       warn_for_collisions (tmp_list2);
1261       merge_tlist (pbefore_sp, tmp_list3, 0);
1262       /* Rather than add both tmp_nosp and tmp_list2, we have to merge the
1263          two first, to avoid warning for (a ? b++ : b++).  */
1264       merge_tlist (&tmp_nosp, tmp_list2, 0);
1265       add_tlist (pno_sp, tmp_nosp, NULL_TREE, 0);
1266       return;
1267
1268     case PREDECREMENT_EXPR:
1269     case PREINCREMENT_EXPR:
1270     case POSTDECREMENT_EXPR:
1271     case POSTINCREMENT_EXPR:
1272       verify_tree (TREE_OPERAND (x, 0), pno_sp, pno_sp, x);
1273       return;
1274
1275     case MODIFY_EXPR:
1276       tmp_before = tmp_nosp = tmp_list3 = 0;
1277       verify_tree (TREE_OPERAND (x, 1), &tmp_before, &tmp_nosp, NULL_TREE);
1278       verify_tree (TREE_OPERAND (x, 0), &tmp_list3, &tmp_list3, x);
1279       /* Expressions inside the LHS are not ordered wrt. the sequence points
1280          in the RHS.  Example:
1281            *a = (a++, 2)
1282          Despite the fact that the modification of "a" is in the before_sp
1283          list (tmp_before), it conflicts with the use of "a" in the LHS.
1284          We can handle this by adding the contents of tmp_list3
1285          to those of tmp_before, and redoing the collision warnings for that
1286          list.  */
1287       add_tlist (&tmp_before, tmp_list3, x, 1);
1288       warn_for_collisions (tmp_before);
1289       /* Exclude the LHS itself here; we first have to merge it into the
1290          tmp_nosp list.  This is done to avoid warning for "a = a"; if we
1291          didn't exclude the LHS, we'd get it twice, once as a read and once
1292          as a write.  */
1293       add_tlist (pno_sp, tmp_list3, x, 0);
1294       warn_for_collisions_1 (TREE_OPERAND (x, 0), x, tmp_nosp, 1);
1295
1296       merge_tlist (pbefore_sp, tmp_before, 0);
1297       if (warning_candidate_p (TREE_OPERAND (x, 0)))
1298         merge_tlist (&tmp_nosp, new_tlist (NULL, TREE_OPERAND (x, 0), x), 0);
1299       add_tlist (pno_sp, tmp_nosp, NULL_TREE, 1);
1300       return;
1301
1302     case CALL_EXPR:
1303       /* We need to warn about conflicts among arguments and conflicts between
1304          args and the function address.  Side effects of the function address,
1305          however, are not ordered by the sequence point of the call.  */
1306       tmp_before = tmp_nosp = tmp_list2 = tmp_list3 = 0;
1307       verify_tree (TREE_OPERAND (x, 0), &tmp_before, &tmp_nosp, NULL_TREE);
1308       if (TREE_OPERAND (x, 1))
1309         verify_tree (TREE_OPERAND (x, 1), &tmp_list2, &tmp_list3, NULL_TREE);
1310       merge_tlist (&tmp_list3, tmp_list2, 0);
1311       add_tlist (&tmp_before, tmp_list3, NULL_TREE, 0);
1312       add_tlist (&tmp_before, tmp_nosp, NULL_TREE, 0);
1313       warn_for_collisions (tmp_before);
1314       add_tlist (pbefore_sp, tmp_before, NULL_TREE, 0);
1315       return;
1316
1317     case TREE_LIST:
1318       /* Scan all the list, e.g. indices of multi dimensional array.  */
1319       while (x)
1320         {
1321           tmp_before = tmp_nosp = 0;
1322           verify_tree (TREE_VALUE (x), &tmp_before, &tmp_nosp, NULL_TREE);
1323           merge_tlist (&tmp_nosp, tmp_before, 0);
1324           add_tlist (pno_sp, tmp_nosp, NULL_TREE, 0);
1325           x = TREE_CHAIN (x);
1326         }
1327       return;
1328
1329     case SAVE_EXPR:
1330       {
1331         struct tlist_cache *t;
1332         for (t = save_expr_cache; t; t = t->next)
1333           if (t->expr == x)
1334             break;
1335
1336         if (!t)
1337           {
1338             t = XOBNEW (&tlist_obstack, struct tlist_cache);
1339             t->next = save_expr_cache;
1340             t->expr = x;
1341             save_expr_cache = t;
1342
1343             tmp_before = tmp_nosp = 0;
1344             verify_tree (TREE_OPERAND (x, 0), &tmp_before, &tmp_nosp, NULL_TREE);
1345             warn_for_collisions (tmp_nosp);
1346
1347             tmp_list3 = 0;
1348             while (tmp_nosp)
1349               {
1350                 struct tlist *t = tmp_nosp;
1351                 tmp_nosp = t->next;
1352                 merge_tlist (&tmp_list3, t, 0);
1353               }
1354             t->cache_before_sp = tmp_before;
1355             t->cache_after_sp = tmp_list3;
1356           }
1357         merge_tlist (pbefore_sp, t->cache_before_sp, 1);
1358         add_tlist (pno_sp, t->cache_after_sp, NULL_TREE, 1);
1359         return;
1360       }
1361
1362     default:
1363       /* For other expressions, simply recurse on their operands.
1364          Manual tail recursion for unary expressions.
1365          Other non-expressions need not be processed.  */
1366       if (cl == tcc_unary)
1367         {
1368           x = TREE_OPERAND (x, 0);
1369           writer = 0;
1370           goto restart;
1371         }
1372       else if (IS_EXPR_CODE_CLASS (cl))
1373         {
1374           int lp;
1375           int max = TREE_CODE_LENGTH (TREE_CODE (x));
1376           for (lp = 0; lp < max; lp++)
1377             {
1378               tmp_before = tmp_nosp = 0;
1379               verify_tree (TREE_OPERAND (x, lp), &tmp_before, &tmp_nosp, 0);
1380               merge_tlist (&tmp_nosp, tmp_before, 0);
1381               add_tlist (pno_sp, tmp_nosp, NULL_TREE, 0);
1382             }
1383         }
1384       return;
1385     }
1386 }
1387
1388 /* Try to warn for undefined behavior in EXPR due to missing sequence
1389    points.  */
1390
1391 void
1392 verify_sequence_points (tree expr)
1393 {
1394   struct tlist *before_sp = 0, *after_sp = 0;
1395
1396   warned_ids = 0;
1397   save_expr_cache = 0;
1398   if (tlist_firstobj == 0)
1399     {
1400       gcc_obstack_init (&tlist_obstack);
1401       tlist_firstobj = (char *) obstack_alloc (&tlist_obstack, 0);
1402     }
1403
1404   verify_tree (expr, &before_sp, &after_sp, 0);
1405   warn_for_collisions (after_sp);
1406   obstack_free (&tlist_obstack, tlist_firstobj);
1407 }
1408 \f
1409 /* Validate the expression after `case' and apply default promotions.  */
1410
1411 static tree
1412 check_case_value (tree value)
1413 {
1414   if (value == NULL_TREE)
1415     return value;
1416
1417   /* Strip NON_LVALUE_EXPRs since we aren't using as an lvalue.  */
1418   STRIP_TYPE_NOPS (value);
1419   /* In C++, the following is allowed:
1420
1421        const int i = 3;
1422        switch (...) { case i: ... }
1423
1424      So, we try to reduce the VALUE to a constant that way.  */
1425   if (c_dialect_cxx ())
1426     {
1427       value = decl_constant_value (value);
1428       STRIP_TYPE_NOPS (value);
1429       value = fold (value);
1430     }
1431
1432   if (TREE_CODE (value) != INTEGER_CST
1433       && value != error_mark_node)
1434     {
1435       error ("case label does not reduce to an integer constant");
1436       value = error_mark_node;
1437     }
1438   else
1439     /* Promote char or short to int.  */
1440     value = default_conversion (value);
1441
1442   constant_expression_warning (value);
1443
1444   return value;
1445 }
1446 \f
1447 /* See if the case values LOW and HIGH are in the range of the original
1448    type (i.e. before the default conversion to int) of the switch testing
1449    expression.
1450    TYPE is the promoted type of the testing expression, and ORIG_TYPE is
1451    the type before promoting it.  CASE_LOW_P is a pointer to the lower
1452    bound of the case label, and CASE_HIGH_P is the upper bound or NULL
1453    if the case is not a case range.
1454    The caller has to make sure that we are not called with NULL for
1455    CASE_LOW_P (i.e. the default case).
1456    Returns true if the case label is in range of ORIG_TYPE (satured or
1457    untouched) or false if the label is out of range.  */
1458
1459 static bool
1460 check_case_bounds (tree type, tree orig_type,
1461                    tree *case_low_p, tree *case_high_p)
1462 {
1463   tree min_value, max_value;
1464   tree case_low = *case_low_p;
1465   tree case_high = case_high_p ? *case_high_p : case_low;
1466
1467   /* If there was a problem with the original type, do nothing.  */
1468   if (orig_type == error_mark_node)
1469     return true;
1470
1471   min_value = TYPE_MIN_VALUE (orig_type);
1472   max_value = TYPE_MAX_VALUE (orig_type);
1473
1474   /* Case label is less than minimum for type.  */
1475   if (tree_int_cst_compare (case_low, min_value) < 0
1476       && tree_int_cst_compare (case_high, min_value) < 0)
1477     {
1478       warning ("case label value is less than minimum value for type");
1479       return false;
1480     }
1481
1482   /* Case value is greater than maximum for type.  */
1483   if (tree_int_cst_compare (case_low, max_value) > 0
1484       && tree_int_cst_compare (case_high, max_value) > 0)
1485     {
1486       warning ("case label value exceeds maximum value for type");
1487       return false;
1488     }
1489
1490   /* Saturate lower case label value to minimum.  */
1491   if (tree_int_cst_compare (case_high, min_value) >= 0
1492       && tree_int_cst_compare (case_low, min_value) < 0)
1493     {
1494       warning ("lower value in case label range"
1495                " less than minimum value for type");
1496       case_low = min_value;
1497     }
1498
1499   /* Saturate upper case label value to maximum.  */
1500   if (tree_int_cst_compare (case_low, max_value) <= 0
1501       && tree_int_cst_compare (case_high, max_value) > 0)
1502     {
1503       warning ("upper value in case label range"
1504                " exceeds maximum value for type");
1505       case_high = max_value;
1506     }
1507
1508   if (*case_low_p != case_low)
1509     *case_low_p = convert (type, case_low);
1510   if (case_high_p && *case_high_p != case_high)
1511     *case_high_p = convert (type, case_high);
1512
1513   return true;
1514 }
1515 \f
1516 /* Return an integer type with BITS bits of precision,
1517    that is unsigned if UNSIGNEDP is nonzero, otherwise signed.  */
1518
1519 tree
1520 c_common_type_for_size (unsigned int bits, int unsignedp)
1521 {
1522   if (bits == TYPE_PRECISION (integer_type_node))
1523     return unsignedp ? unsigned_type_node : integer_type_node;
1524
1525   if (bits == TYPE_PRECISION (signed_char_type_node))
1526     return unsignedp ? unsigned_char_type_node : signed_char_type_node;
1527
1528   if (bits == TYPE_PRECISION (short_integer_type_node))
1529     return unsignedp ? short_unsigned_type_node : short_integer_type_node;
1530
1531   if (bits == TYPE_PRECISION (long_integer_type_node))
1532     return unsignedp ? long_unsigned_type_node : long_integer_type_node;
1533
1534   if (bits == TYPE_PRECISION (long_long_integer_type_node))
1535     return (unsignedp ? long_long_unsigned_type_node
1536             : long_long_integer_type_node);
1537
1538   if (bits == TYPE_PRECISION (widest_integer_literal_type_node))
1539     return (unsignedp ? widest_unsigned_literal_type_node
1540             : widest_integer_literal_type_node);
1541
1542   if (bits <= TYPE_PRECISION (intQI_type_node))
1543     return unsignedp ? unsigned_intQI_type_node : intQI_type_node;
1544
1545   if (bits <= TYPE_PRECISION (intHI_type_node))
1546     return unsignedp ? unsigned_intHI_type_node : intHI_type_node;
1547
1548   if (bits <= TYPE_PRECISION (intSI_type_node))
1549     return unsignedp ? unsigned_intSI_type_node : intSI_type_node;
1550
1551   if (bits <= TYPE_PRECISION (intDI_type_node))
1552     return unsignedp ? unsigned_intDI_type_node : intDI_type_node;
1553
1554   return 0;
1555 }
1556
1557 /* Used for communication between c_common_type_for_mode and
1558    c_register_builtin_type.  */
1559 static GTY(()) tree registered_builtin_types;
1560
1561 /* Return a data type that has machine mode MODE.
1562    If the mode is an integer,
1563    then UNSIGNEDP selects between signed and unsigned types.  */
1564
1565 tree
1566 c_common_type_for_mode (enum machine_mode mode, int unsignedp)
1567 {
1568   tree t;
1569
1570   if (mode == TYPE_MODE (integer_type_node))
1571     return unsignedp ? unsigned_type_node : integer_type_node;
1572
1573   if (mode == TYPE_MODE (signed_char_type_node))
1574     return unsignedp ? unsigned_char_type_node : signed_char_type_node;
1575
1576   if (mode == TYPE_MODE (short_integer_type_node))
1577     return unsignedp ? short_unsigned_type_node : short_integer_type_node;
1578
1579   if (mode == TYPE_MODE (long_integer_type_node))
1580     return unsignedp ? long_unsigned_type_node : long_integer_type_node;
1581
1582   if (mode == TYPE_MODE (long_long_integer_type_node))
1583     return unsignedp ? long_long_unsigned_type_node : long_long_integer_type_node;
1584
1585   if (mode == TYPE_MODE (widest_integer_literal_type_node))
1586     return unsignedp ? widest_unsigned_literal_type_node
1587                      : widest_integer_literal_type_node;
1588
1589   if (mode == QImode)
1590     return unsignedp ? unsigned_intQI_type_node : intQI_type_node;
1591
1592   if (mode == HImode)
1593     return unsignedp ? unsigned_intHI_type_node : intHI_type_node;
1594
1595   if (mode == SImode)
1596     return unsignedp ? unsigned_intSI_type_node : intSI_type_node;
1597
1598   if (mode == DImode)
1599     return unsignedp ? unsigned_intDI_type_node : intDI_type_node;
1600
1601 #if HOST_BITS_PER_WIDE_INT >= 64
1602   if (mode == TYPE_MODE (intTI_type_node))
1603     return unsignedp ? unsigned_intTI_type_node : intTI_type_node;
1604 #endif
1605
1606   if (mode == TYPE_MODE (float_type_node))
1607     return float_type_node;
1608
1609   if (mode == TYPE_MODE (double_type_node))
1610     return double_type_node;
1611
1612   if (mode == TYPE_MODE (long_double_type_node))
1613     return long_double_type_node;
1614
1615   if (mode == TYPE_MODE (void_type_node))
1616     return void_type_node;
1617
1618   if (mode == TYPE_MODE (build_pointer_type (char_type_node)))
1619     return unsignedp ? make_unsigned_type (mode) : make_signed_type (mode);
1620
1621   if (mode == TYPE_MODE (build_pointer_type (integer_type_node)))
1622     return unsignedp ? make_unsigned_type (mode) : make_signed_type (mode);
1623
1624   if (VECTOR_MODE_P (mode))
1625     {
1626       enum machine_mode inner_mode = GET_MODE_INNER (mode);
1627       tree inner_type = c_common_type_for_mode (inner_mode, unsignedp);
1628       if (inner_type != NULL_TREE)
1629         return build_vector_type_for_mode (inner_type, mode);
1630     }
1631
1632   for (t = registered_builtin_types; t; t = TREE_CHAIN (t))
1633     if (TYPE_MODE (TREE_VALUE (t)) == mode)
1634       return TREE_VALUE (t);
1635
1636   return 0;
1637 }
1638
1639 /* Return an unsigned type the same as TYPE in other respects.  */
1640 tree
1641 c_common_unsigned_type (tree type)
1642 {
1643   tree type1 = TYPE_MAIN_VARIANT (type);
1644   if (type1 == signed_char_type_node || type1 == char_type_node)
1645     return unsigned_char_type_node;
1646   if (type1 == integer_type_node)
1647     return unsigned_type_node;
1648   if (type1 == short_integer_type_node)
1649     return short_unsigned_type_node;
1650   if (type1 == long_integer_type_node)
1651     return long_unsigned_type_node;
1652   if (type1 == long_long_integer_type_node)
1653     return long_long_unsigned_type_node;
1654   if (type1 == widest_integer_literal_type_node)
1655     return widest_unsigned_literal_type_node;
1656 #if HOST_BITS_PER_WIDE_INT >= 64
1657   if (type1 == intTI_type_node)
1658     return unsigned_intTI_type_node;
1659 #endif
1660   if (type1 == intDI_type_node)
1661     return unsigned_intDI_type_node;
1662   if (type1 == intSI_type_node)
1663     return unsigned_intSI_type_node;
1664   if (type1 == intHI_type_node)
1665     return unsigned_intHI_type_node;
1666   if (type1 == intQI_type_node)
1667     return unsigned_intQI_type_node;
1668
1669   return c_common_signed_or_unsigned_type (1, type);
1670 }
1671
1672 /* Return a signed type the same as TYPE in other respects.  */
1673
1674 tree
1675 c_common_signed_type (tree type)
1676 {
1677   tree type1 = TYPE_MAIN_VARIANT (type);
1678   if (type1 == unsigned_char_type_node || type1 == char_type_node)
1679     return signed_char_type_node;
1680   if (type1 == unsigned_type_node)
1681     return integer_type_node;
1682   if (type1 == short_unsigned_type_node)
1683     return short_integer_type_node;
1684   if (type1 == long_unsigned_type_node)
1685     return long_integer_type_node;
1686   if (type1 == long_long_unsigned_type_node)
1687     return long_long_integer_type_node;
1688   if (type1 == widest_unsigned_literal_type_node)
1689     return widest_integer_literal_type_node;
1690 #if HOST_BITS_PER_WIDE_INT >= 64
1691   if (type1 == unsigned_intTI_type_node)
1692     return intTI_type_node;
1693 #endif
1694   if (type1 == unsigned_intDI_type_node)
1695     return intDI_type_node;
1696   if (type1 == unsigned_intSI_type_node)
1697     return intSI_type_node;
1698   if (type1 == unsigned_intHI_type_node)
1699     return intHI_type_node;
1700   if (type1 == unsigned_intQI_type_node)
1701     return intQI_type_node;
1702
1703   return c_common_signed_or_unsigned_type (0, type);
1704 }
1705
1706 /* Return a type the same as TYPE except unsigned or
1707    signed according to UNSIGNEDP.  */
1708
1709 tree
1710 c_common_signed_or_unsigned_type (int unsignedp, tree type)
1711 {
1712   if (!INTEGRAL_TYPE_P (type)
1713       || TYPE_UNSIGNED (type) == unsignedp)
1714     return type;
1715
1716   /* For ENUMERAL_TYPEs in C++, must check the mode of the types, not
1717      the precision; they have precision set to match their range, but
1718      may use a wider mode to match an ABI.  If we change modes, we may
1719      wind up with bad conversions.  For INTEGER_TYPEs in C, must check
1720      the precision as well, so as to yield correct results for
1721      bit-field types.  C++ does not have these separate bit-field
1722      types, and producing a signed or unsigned variant of an
1723      ENUMERAL_TYPE may cause other problems as well.  */
1724
1725 #define TYPE_OK(node)                                                       \
1726   (TYPE_MODE (type) == TYPE_MODE (node)                                     \
1727    && (c_dialect_cxx () || TYPE_PRECISION (type) == TYPE_PRECISION (node)))
1728   if (TYPE_OK (signed_char_type_node))
1729     return unsignedp ? unsigned_char_type_node : signed_char_type_node;
1730   if (TYPE_OK (integer_type_node))
1731     return unsignedp ? unsigned_type_node : integer_type_node;
1732   if (TYPE_OK (short_integer_type_node))
1733     return unsignedp ? short_unsigned_type_node : short_integer_type_node;
1734   if (TYPE_OK (long_integer_type_node))
1735     return unsignedp ? long_unsigned_type_node : long_integer_type_node;
1736   if (TYPE_OK (long_long_integer_type_node))
1737     return (unsignedp ? long_long_unsigned_type_node
1738             : long_long_integer_type_node);
1739   if (TYPE_OK (widest_integer_literal_type_node))
1740     return (unsignedp ? widest_unsigned_literal_type_node
1741             : widest_integer_literal_type_node);
1742
1743 #if HOST_BITS_PER_WIDE_INT >= 64
1744   if (TYPE_OK (intTI_type_node))
1745     return unsignedp ? unsigned_intTI_type_node : intTI_type_node;
1746 #endif
1747   if (TYPE_OK (intDI_type_node))
1748     return unsignedp ? unsigned_intDI_type_node : intDI_type_node;
1749   if (TYPE_OK (intSI_type_node))
1750     return unsignedp ? unsigned_intSI_type_node : intSI_type_node;
1751   if (TYPE_OK (intHI_type_node))
1752     return unsignedp ? unsigned_intHI_type_node : intHI_type_node;
1753   if (TYPE_OK (intQI_type_node))
1754     return unsignedp ? unsigned_intQI_type_node : intQI_type_node;
1755 #undef TYPE_OK
1756
1757   if (c_dialect_cxx ())
1758     return type;
1759   else
1760     return build_nonstandard_integer_type (TYPE_PRECISION (type), unsignedp);
1761 }
1762
1763 /* The C version of the register_builtin_type langhook.  */
1764
1765 void
1766 c_register_builtin_type (tree type, const char* name)
1767 {
1768   tree decl;
1769
1770   decl = build_decl (TYPE_DECL, get_identifier (name), type);
1771   DECL_ARTIFICIAL (decl) = 1;
1772   if (!TYPE_NAME (type))
1773     TYPE_NAME (type) = decl;
1774   pushdecl (decl);
1775
1776   registered_builtin_types = tree_cons (0, type, registered_builtin_types);
1777 }
1778
1779 \f
1780 /* Return the minimum number of bits needed to represent VALUE in a
1781    signed or unsigned type, UNSIGNEDP says which.  */
1782
1783 unsigned int
1784 min_precision (tree value, int unsignedp)
1785 {
1786   int log;
1787
1788   /* If the value is negative, compute its negative minus 1.  The latter
1789      adjustment is because the absolute value of the largest negative value
1790      is one larger than the largest positive value.  This is equivalent to
1791      a bit-wise negation, so use that operation instead.  */
1792
1793   if (tree_int_cst_sgn (value) < 0)
1794     value = fold (build1 (BIT_NOT_EXPR, TREE_TYPE (value), value));
1795
1796   /* Return the number of bits needed, taking into account the fact
1797      that we need one more bit for a signed than unsigned type.  */
1798
1799   if (integer_zerop (value))
1800     log = 0;
1801   else
1802     log = tree_floor_log2 (value);
1803
1804   return log + 1 + !unsignedp;
1805 }
1806 \f
1807 /* Print an error message for invalid operands to arith operation
1808    CODE.  NOP_EXPR is used as a special case (see
1809    c_common_truthvalue_conversion).  */
1810
1811 void
1812 binary_op_error (enum tree_code code)
1813 {
1814   const char *opname;
1815
1816   switch (code)
1817     {
1818     case NOP_EXPR:
1819       error ("invalid truth-value expression");
1820       return;
1821
1822     case PLUS_EXPR:
1823       opname = "+"; break;
1824     case MINUS_EXPR:
1825       opname = "-"; break;
1826     case MULT_EXPR:
1827       opname = "*"; break;
1828     case MAX_EXPR:
1829       opname = "max"; break;
1830     case MIN_EXPR:
1831       opname = "min"; break;
1832     case EQ_EXPR:
1833       opname = "=="; break;
1834     case NE_EXPR:
1835       opname = "!="; break;
1836     case LE_EXPR:
1837       opname = "<="; break;
1838     case GE_EXPR:
1839       opname = ">="; break;
1840     case LT_EXPR:
1841       opname = "<"; break;
1842     case GT_EXPR:
1843       opname = ">"; break;
1844     case LSHIFT_EXPR:
1845       opname = "<<"; break;
1846     case RSHIFT_EXPR:
1847       opname = ">>"; break;
1848     case TRUNC_MOD_EXPR:
1849     case FLOOR_MOD_EXPR:
1850       opname = "%"; break;
1851     case TRUNC_DIV_EXPR:
1852     case FLOOR_DIV_EXPR:
1853       opname = "/"; break;
1854     case BIT_AND_EXPR:
1855       opname = "&"; break;
1856     case BIT_IOR_EXPR:
1857       opname = "|"; break;
1858     case TRUTH_ANDIF_EXPR:
1859       opname = "&&"; break;
1860     case TRUTH_ORIF_EXPR:
1861       opname = "||"; break;
1862     case BIT_XOR_EXPR:
1863       opname = "^"; break;
1864     default:
1865       gcc_unreachable ();
1866     }
1867   error ("invalid operands to binary %s", opname);
1868 }
1869 \f
1870 /* Subroutine of build_binary_op, used for comparison operations.
1871    See if the operands have both been converted from subword integer types
1872    and, if so, perhaps change them both back to their original type.
1873    This function is also responsible for converting the two operands
1874    to the proper common type for comparison.
1875
1876    The arguments of this function are all pointers to local variables
1877    of build_binary_op: OP0_PTR is &OP0, OP1_PTR is &OP1,
1878    RESTYPE_PTR is &RESULT_TYPE and RESCODE_PTR is &RESULTCODE.
1879
1880    If this function returns nonzero, it means that the comparison has
1881    a constant value.  What this function returns is an expression for
1882    that value.  */
1883
1884 tree
1885 shorten_compare (tree *op0_ptr, tree *op1_ptr, tree *restype_ptr,
1886                  enum tree_code *rescode_ptr)
1887 {
1888   tree type;
1889   tree op0 = *op0_ptr;
1890   tree op1 = *op1_ptr;
1891   int unsignedp0, unsignedp1;
1892   int real1, real2;
1893   tree primop0, primop1;
1894   enum tree_code code = *rescode_ptr;
1895
1896   /* Throw away any conversions to wider types
1897      already present in the operands.  */
1898
1899   primop0 = get_narrower (op0, &unsignedp0);
1900   primop1 = get_narrower (op1, &unsignedp1);
1901
1902   /* Handle the case that OP0 does not *contain* a conversion
1903      but it *requires* conversion to FINAL_TYPE.  */
1904
1905   if (op0 == primop0 && TREE_TYPE (op0) != *restype_ptr)
1906     unsignedp0 = TYPE_UNSIGNED (TREE_TYPE (op0));
1907   if (op1 == primop1 && TREE_TYPE (op1) != *restype_ptr)
1908     unsignedp1 = TYPE_UNSIGNED (TREE_TYPE (op1));
1909
1910   /* If one of the operands must be floated, we cannot optimize.  */
1911   real1 = TREE_CODE (TREE_TYPE (primop0)) == REAL_TYPE;
1912   real2 = TREE_CODE (TREE_TYPE (primop1)) == REAL_TYPE;
1913
1914   /* If first arg is constant, swap the args (changing operation
1915      so value is preserved), for canonicalization.  Don't do this if
1916      the second arg is 0.  */
1917
1918   if (TREE_CONSTANT (primop0)
1919       && !integer_zerop (primop1) && !real_zerop (primop1))
1920     {
1921       tree tem = primop0;
1922       int temi = unsignedp0;
1923       primop0 = primop1;
1924       primop1 = tem;
1925       tem = op0;
1926       op0 = op1;
1927       op1 = tem;
1928       *op0_ptr = op0;
1929       *op1_ptr = op1;
1930       unsignedp0 = unsignedp1;
1931       unsignedp1 = temi;
1932       temi = real1;
1933       real1 = real2;
1934       real2 = temi;
1935
1936       switch (code)
1937         {
1938         case LT_EXPR:
1939           code = GT_EXPR;
1940           break;
1941         case GT_EXPR:
1942           code = LT_EXPR;
1943           break;
1944         case LE_EXPR:
1945           code = GE_EXPR;
1946           break;
1947         case GE_EXPR:
1948           code = LE_EXPR;
1949           break;
1950         default:
1951           break;
1952         }
1953       *rescode_ptr = code;
1954     }
1955
1956   /* If comparing an integer against a constant more bits wide,
1957      maybe we can deduce a value of 1 or 0 independent of the data.
1958      Or else truncate the constant now
1959      rather than extend the variable at run time.
1960
1961      This is only interesting if the constant is the wider arg.
1962      Also, it is not safe if the constant is unsigned and the
1963      variable arg is signed, since in this case the variable
1964      would be sign-extended and then regarded as unsigned.
1965      Our technique fails in this case because the lowest/highest
1966      possible unsigned results don't follow naturally from the
1967      lowest/highest possible values of the variable operand.
1968      For just EQ_EXPR and NE_EXPR there is another technique that
1969      could be used: see if the constant can be faithfully represented
1970      in the other operand's type, by truncating it and reextending it
1971      and see if that preserves the constant's value.  */
1972
1973   if (!real1 && !real2
1974       && TREE_CODE (primop1) == INTEGER_CST
1975       && TYPE_PRECISION (TREE_TYPE (primop0)) < TYPE_PRECISION (*restype_ptr))
1976     {
1977       int min_gt, max_gt, min_lt, max_lt;
1978       tree maxval, minval;
1979       /* 1 if comparison is nominally unsigned.  */
1980       int unsignedp = TYPE_UNSIGNED (*restype_ptr);
1981       tree val;
1982
1983       type = c_common_signed_or_unsigned_type (unsignedp0,
1984                                                TREE_TYPE (primop0));
1985
1986       /* In C, if TYPE is an enumeration, then we need to get its
1987          min/max values from its underlying integral type, not the
1988          enumerated type itself.  In C++, TYPE_MAX_VALUE and
1989          TYPE_MIN_VALUE have already been set correctly on the
1990          enumeration type.  */
1991       if (!c_dialect_cxx () && TREE_CODE (type) == ENUMERAL_TYPE)
1992         type = c_common_type_for_size (TYPE_PRECISION (type), unsignedp0);
1993
1994       maxval = TYPE_MAX_VALUE (type);
1995       minval = TYPE_MIN_VALUE (type);
1996
1997       if (unsignedp && !unsignedp0)
1998         *restype_ptr = c_common_signed_type (*restype_ptr);
1999
2000       if (TREE_TYPE (primop1) != *restype_ptr)
2001         {
2002           /* Convert primop1 to target type, but do not introduce
2003              additional overflow.  We know primop1 is an int_cst.  */
2004           tree tmp = build_int_cst_wide (*restype_ptr,
2005                                          TREE_INT_CST_LOW (primop1),
2006                                          TREE_INT_CST_HIGH (primop1));
2007
2008           primop1 = force_fit_type (tmp, 0, TREE_OVERFLOW (primop1),
2009                                     TREE_CONSTANT_OVERFLOW (primop1));
2010         }
2011       if (type != *restype_ptr)
2012         {
2013           minval = convert (*restype_ptr, minval);
2014           maxval = convert (*restype_ptr, maxval);
2015         }
2016
2017       if (unsignedp && unsignedp0)
2018         {
2019           min_gt = INT_CST_LT_UNSIGNED (primop1, minval);
2020           max_gt = INT_CST_LT_UNSIGNED (primop1, maxval);
2021           min_lt = INT_CST_LT_UNSIGNED (minval, primop1);
2022           max_lt = INT_CST_LT_UNSIGNED (maxval, primop1);
2023         }
2024       else
2025         {
2026           min_gt = INT_CST_LT (primop1, minval);
2027           max_gt = INT_CST_LT (primop1, maxval);
2028           min_lt = INT_CST_LT (minval, primop1);
2029           max_lt = INT_CST_LT (maxval, primop1);
2030         }
2031
2032       val = 0;
2033       /* This used to be a switch, but Genix compiler can't handle that.  */
2034       if (code == NE_EXPR)
2035         {
2036           if (max_lt || min_gt)
2037             val = truthvalue_true_node;
2038         }
2039       else if (code == EQ_EXPR)
2040         {
2041           if (max_lt || min_gt)
2042             val = truthvalue_false_node;
2043         }
2044       else if (code == LT_EXPR)
2045         {
2046           if (max_lt)
2047             val = truthvalue_true_node;
2048           if (!min_lt)
2049             val = truthvalue_false_node;
2050         }
2051       else if (code == GT_EXPR)
2052         {
2053           if (min_gt)
2054             val = truthvalue_true_node;
2055           if (!max_gt)
2056             val = truthvalue_false_node;
2057         }
2058       else if (code == LE_EXPR)
2059         {
2060           if (!max_gt)
2061             val = truthvalue_true_node;
2062           if (min_gt)
2063             val = truthvalue_false_node;
2064         }
2065       else if (code == GE_EXPR)
2066         {
2067           if (!min_lt)
2068             val = truthvalue_true_node;
2069           if (max_lt)
2070             val = truthvalue_false_node;
2071         }
2072
2073       /* If primop0 was sign-extended and unsigned comparison specd,
2074          we did a signed comparison above using the signed type bounds.
2075          But the comparison we output must be unsigned.
2076
2077          Also, for inequalities, VAL is no good; but if the signed
2078          comparison had *any* fixed result, it follows that the
2079          unsigned comparison just tests the sign in reverse
2080          (positive values are LE, negative ones GE).
2081          So we can generate an unsigned comparison
2082          against an extreme value of the signed type.  */
2083
2084       if (unsignedp && !unsignedp0)
2085         {
2086           if (val != 0)
2087             switch (code)
2088               {
2089               case LT_EXPR:
2090               case GE_EXPR:
2091                 primop1 = TYPE_MIN_VALUE (type);
2092                 val = 0;
2093                 break;
2094
2095               case LE_EXPR:
2096               case GT_EXPR:
2097                 primop1 = TYPE_MAX_VALUE (type);
2098                 val = 0;
2099                 break;
2100
2101               default:
2102                 break;
2103               }
2104           type = c_common_unsigned_type (type);
2105         }
2106
2107       if (TREE_CODE (primop0) != INTEGER_CST)
2108         {
2109           if (val == truthvalue_false_node)
2110             warning ("comparison is always false due to limited range of data type");
2111           if (val == truthvalue_true_node)
2112             warning ("comparison is always true due to limited range of data type");
2113         }
2114
2115       if (val != 0)
2116         {
2117           /* Don't forget to evaluate PRIMOP0 if it has side effects.  */
2118           if (TREE_SIDE_EFFECTS (primop0))
2119             return build2 (COMPOUND_EXPR, TREE_TYPE (val), primop0, val);
2120           return val;
2121         }
2122
2123       /* Value is not predetermined, but do the comparison
2124          in the type of the operand that is not constant.
2125          TYPE is already properly set.  */
2126     }
2127   else if (real1 && real2
2128            && (TYPE_PRECISION (TREE_TYPE (primop0))
2129                == TYPE_PRECISION (TREE_TYPE (primop1))))
2130     type = TREE_TYPE (primop0);
2131
2132   /* If args' natural types are both narrower than nominal type
2133      and both extend in the same manner, compare them
2134      in the type of the wider arg.
2135      Otherwise must actually extend both to the nominal
2136      common type lest different ways of extending
2137      alter the result.
2138      (eg, (short)-1 == (unsigned short)-1  should be 0.)  */
2139
2140   else if (unsignedp0 == unsignedp1 && real1 == real2
2141            && TYPE_PRECISION (TREE_TYPE (primop0)) < TYPE_PRECISION (*restype_ptr)
2142            && TYPE_PRECISION (TREE_TYPE (primop1)) < TYPE_PRECISION (*restype_ptr))
2143     {
2144       type = common_type (TREE_TYPE (primop0), TREE_TYPE (primop1));
2145       type = c_common_signed_or_unsigned_type (unsignedp0
2146                                                || TYPE_UNSIGNED (*restype_ptr),
2147                                                type);
2148       /* Make sure shorter operand is extended the right way
2149          to match the longer operand.  */
2150       primop0
2151         = convert (c_common_signed_or_unsigned_type (unsignedp0,
2152                                                      TREE_TYPE (primop0)),
2153                    primop0);
2154       primop1
2155         = convert (c_common_signed_or_unsigned_type (unsignedp1,
2156                                                      TREE_TYPE (primop1)),
2157                    primop1);
2158     }
2159   else
2160     {
2161       /* Here we must do the comparison on the nominal type
2162          using the args exactly as we received them.  */
2163       type = *restype_ptr;
2164       primop0 = op0;
2165       primop1 = op1;
2166
2167       if (!real1 && !real2 && integer_zerop (primop1)
2168           && TYPE_UNSIGNED (*restype_ptr))
2169         {
2170           tree value = 0;
2171           switch (code)
2172             {
2173             case GE_EXPR:
2174               /* All unsigned values are >= 0, so we warn if extra warnings
2175                  are requested.  However, if OP0 is a constant that is
2176                  >= 0, the signedness of the comparison isn't an issue,
2177                  so suppress the warning.  */
2178               if (extra_warnings && !in_system_header
2179                   && !(TREE_CODE (primop0) == INTEGER_CST
2180                        && !TREE_OVERFLOW (convert (c_common_signed_type (type),
2181                                                    primop0))))
2182                 warning ("comparison of unsigned expression >= 0 is always true");
2183               value = truthvalue_true_node;
2184               break;
2185
2186             case LT_EXPR:
2187               if (extra_warnings && !in_system_header
2188                   && !(TREE_CODE (primop0) == INTEGER_CST
2189                        && !TREE_OVERFLOW (convert (c_common_signed_type (type),
2190                                                    primop0))))
2191                 warning ("comparison of unsigned expression < 0 is always false");
2192               value = truthvalue_false_node;
2193               break;
2194
2195             default:
2196               break;
2197             }
2198
2199           if (value != 0)
2200             {
2201               /* Don't forget to evaluate PRIMOP0 if it has side effects.  */
2202               if (TREE_SIDE_EFFECTS (primop0))
2203                 return build2 (COMPOUND_EXPR, TREE_TYPE (value),
2204                                primop0, value);
2205               return value;
2206             }
2207         }
2208     }
2209
2210   *op0_ptr = convert (type, primop0);
2211   *op1_ptr = convert (type, primop1);
2212
2213   *restype_ptr = truthvalue_type_node;
2214
2215   return 0;
2216 }
2217 \f
2218 /* Return a tree for the sum or difference (RESULTCODE says which)
2219    of pointer PTROP and integer INTOP.  */
2220
2221 tree
2222 pointer_int_sum (enum tree_code resultcode, tree ptrop, tree intop)
2223 {
2224   tree size_exp;
2225
2226   /* The result is a pointer of the same type that is being added.  */
2227
2228   tree result_type = TREE_TYPE (ptrop);
2229
2230   if (TREE_CODE (TREE_TYPE (result_type)) == VOID_TYPE)
2231     {
2232       if (pedantic || warn_pointer_arith)
2233         pedwarn ("pointer of type %<void *%> used in arithmetic");
2234       size_exp = integer_one_node;
2235     }
2236   else if (TREE_CODE (TREE_TYPE (result_type)) == FUNCTION_TYPE)
2237     {
2238       if (pedantic || warn_pointer_arith)
2239         pedwarn ("pointer to a function used in arithmetic");
2240       size_exp = integer_one_node;
2241     }
2242   else if (TREE_CODE (TREE_TYPE (result_type)) == METHOD_TYPE)
2243     {
2244       if (pedantic || warn_pointer_arith)
2245         pedwarn ("pointer to member function used in arithmetic");
2246       size_exp = integer_one_node;
2247     }
2248   else
2249     size_exp = size_in_bytes (TREE_TYPE (result_type));
2250
2251   /* If what we are about to multiply by the size of the elements
2252      contains a constant term, apply distributive law
2253      and multiply that constant term separately.
2254      This helps produce common subexpressions.  */
2255
2256   if ((TREE_CODE (intop) == PLUS_EXPR || TREE_CODE (intop) == MINUS_EXPR)
2257       && !TREE_CONSTANT (intop)
2258       && TREE_CONSTANT (TREE_OPERAND (intop, 1))
2259       && TREE_CONSTANT (size_exp)
2260       /* If the constant comes from pointer subtraction,
2261          skip this optimization--it would cause an error.  */
2262       && TREE_CODE (TREE_TYPE (TREE_OPERAND (intop, 0))) == INTEGER_TYPE
2263       /* If the constant is unsigned, and smaller than the pointer size,
2264          then we must skip this optimization.  This is because it could cause
2265          an overflow error if the constant is negative but INTOP is not.  */
2266       && (!TYPE_UNSIGNED (TREE_TYPE (intop))
2267           || (TYPE_PRECISION (TREE_TYPE (intop))
2268               == TYPE_PRECISION (TREE_TYPE (ptrop)))))
2269     {
2270       enum tree_code subcode = resultcode;
2271       tree int_type = TREE_TYPE (intop);
2272       if (TREE_CODE (intop) == MINUS_EXPR)
2273         subcode = (subcode == PLUS_EXPR ? MINUS_EXPR : PLUS_EXPR);
2274       /* Convert both subexpression types to the type of intop,
2275          because weird cases involving pointer arithmetic
2276          can result in a sum or difference with different type args.  */
2277       ptrop = build_binary_op (subcode, ptrop,
2278                                convert (int_type, TREE_OPERAND (intop, 1)), 1);
2279       intop = convert (int_type, TREE_OPERAND (intop, 0));
2280     }
2281
2282   /* Convert the integer argument to a type the same size as sizetype
2283      so the multiply won't overflow spuriously.  */
2284
2285   if (TYPE_PRECISION (TREE_TYPE (intop)) != TYPE_PRECISION (sizetype)
2286       || TYPE_UNSIGNED (TREE_TYPE (intop)) != TYPE_UNSIGNED (sizetype))
2287     intop = convert (c_common_type_for_size (TYPE_PRECISION (sizetype),
2288                                              TYPE_UNSIGNED (sizetype)), intop);
2289
2290   /* Replace the integer argument with a suitable product by the object size.
2291      Do this multiplication as signed, then convert to the appropriate
2292      pointer type (actually unsigned integral).  */
2293
2294   intop = convert (result_type,
2295                    build_binary_op (MULT_EXPR, intop,
2296                                     convert (TREE_TYPE (intop), size_exp), 1));
2297
2298   /* Create the sum or difference.  */
2299   return fold (build2 (resultcode, result_type, ptrop, intop));
2300 }
2301 \f
2302 /* Prepare expr to be an argument of a TRUTH_NOT_EXPR,
2303    or validate its data type for an `if' or `while' statement or ?..: exp.
2304
2305    This preparation consists of taking the ordinary
2306    representation of an expression expr and producing a valid tree
2307    boolean expression describing whether expr is nonzero.  We could
2308    simply always do build_binary_op (NE_EXPR, expr, truthvalue_false_node, 1),
2309    but we optimize comparisons, &&, ||, and !.
2310
2311    The resulting type should always be `truthvalue_type_node'.  */
2312
2313 tree
2314 c_common_truthvalue_conversion (tree expr)
2315 {
2316   if (TREE_CODE (expr) == ERROR_MARK)
2317     return expr;
2318
2319   if (TREE_CODE (expr) == FUNCTION_DECL)
2320     expr = build_unary_op (ADDR_EXPR, expr, 0);
2321
2322   switch (TREE_CODE (expr))
2323     {
2324     case EQ_EXPR:   case NE_EXPR:   case UNEQ_EXPR: case LTGT_EXPR:
2325     case LE_EXPR:   case GE_EXPR:   case LT_EXPR:   case GT_EXPR:
2326     case UNLE_EXPR: case UNGE_EXPR: case UNLT_EXPR: case UNGT_EXPR:
2327     case ORDERED_EXPR: case UNORDERED_EXPR:
2328     case TRUTH_ANDIF_EXPR:
2329     case TRUTH_ORIF_EXPR:
2330     case TRUTH_AND_EXPR:
2331     case TRUTH_OR_EXPR:
2332     case TRUTH_XOR_EXPR:
2333     case TRUTH_NOT_EXPR:
2334       TREE_TYPE (expr) = truthvalue_type_node;
2335       return expr;
2336
2337     case ERROR_MARK:
2338       return expr;
2339
2340     case INTEGER_CST:
2341       return integer_zerop (expr) ? truthvalue_false_node : truthvalue_true_node;
2342
2343     case REAL_CST:
2344       return real_zerop (expr) ? truthvalue_false_node : truthvalue_true_node;
2345
2346     case ADDR_EXPR:
2347       {
2348         if (TREE_CODE (TREE_OPERAND (expr, 0)) == FUNCTION_DECL
2349             && !DECL_WEAK (TREE_OPERAND (expr, 0)))
2350           {
2351             /* Common Ada/Pascal programmer's mistake.  We always warn
2352                about this since it is so bad.  */
2353             warning ("the address of %qD, will always evaluate as %<true%>",
2354                      TREE_OPERAND (expr, 0));
2355             return truthvalue_true_node;
2356           }
2357
2358         /* If we are taking the address of an external decl, it might be
2359            zero if it is weak, so we cannot optimize.  */
2360         if (DECL_P (TREE_OPERAND (expr, 0))
2361             && DECL_EXTERNAL (TREE_OPERAND (expr, 0)))
2362           break;
2363
2364         if (TREE_SIDE_EFFECTS (TREE_OPERAND (expr, 0)))
2365           return build2 (COMPOUND_EXPR, truthvalue_type_node,
2366                          TREE_OPERAND (expr, 0), truthvalue_true_node);
2367         else
2368           return truthvalue_true_node;
2369       }
2370
2371     case COMPLEX_EXPR:
2372       return build_binary_op ((TREE_SIDE_EFFECTS (TREE_OPERAND (expr, 1))
2373                                ? TRUTH_OR_EXPR : TRUTH_ORIF_EXPR),
2374                 lang_hooks.truthvalue_conversion (TREE_OPERAND (expr, 0)),
2375                 lang_hooks.truthvalue_conversion (TREE_OPERAND (expr, 1)),
2376                               0);
2377
2378     case NEGATE_EXPR:
2379     case ABS_EXPR:
2380     case FLOAT_EXPR:
2381       /* These don't change whether an object is nonzero or zero.  */
2382       return lang_hooks.truthvalue_conversion (TREE_OPERAND (expr, 0));
2383
2384     case LROTATE_EXPR:
2385     case RROTATE_EXPR:
2386       /* These don't change whether an object is zero or nonzero, but
2387          we can't ignore them if their second arg has side-effects.  */
2388       if (TREE_SIDE_EFFECTS (TREE_OPERAND (expr, 1)))
2389         return build2 (COMPOUND_EXPR, truthvalue_type_node,
2390                        TREE_OPERAND (expr, 1),
2391                        lang_hooks.truthvalue_conversion (TREE_OPERAND (expr, 0)));
2392       else
2393         return lang_hooks.truthvalue_conversion (TREE_OPERAND (expr, 0));
2394
2395     case COND_EXPR:
2396       /* Distribute the conversion into the arms of a COND_EXPR.  */
2397       return fold (build3 (COND_EXPR, truthvalue_type_node,
2398                 TREE_OPERAND (expr, 0),
2399                 lang_hooks.truthvalue_conversion (TREE_OPERAND (expr, 1)),
2400                 lang_hooks.truthvalue_conversion (TREE_OPERAND (expr, 2))));
2401
2402     case CONVERT_EXPR:
2403       /* Don't cancel the effect of a CONVERT_EXPR from a REFERENCE_TYPE,
2404          since that affects how `default_conversion' will behave.  */
2405       if (TREE_CODE (TREE_TYPE (expr)) == REFERENCE_TYPE
2406           || TREE_CODE (TREE_TYPE (TREE_OPERAND (expr, 0))) == REFERENCE_TYPE)
2407         break;
2408       /* Fall through....  */
2409     case NOP_EXPR:
2410       /* If this is widening the argument, we can ignore it.  */
2411       if (TYPE_PRECISION (TREE_TYPE (expr))
2412           >= TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (expr, 0))))
2413         return lang_hooks.truthvalue_conversion (TREE_OPERAND (expr, 0));
2414       break;
2415
2416     case MINUS_EXPR:
2417       /* Perhaps reduce (x - y) != 0 to (x != y).  The expressions
2418          aren't guaranteed to the be same for modes that can represent
2419          infinity, since if x and y are both +infinity, or both
2420          -infinity, then x - y is not a number.
2421
2422          Note that this transformation is safe when x or y is NaN.
2423          (x - y) is then NaN, and both (x - y) != 0 and x != y will
2424          be false.  */
2425       if (HONOR_INFINITIES (TYPE_MODE (TREE_TYPE (TREE_OPERAND (expr, 0)))))
2426         break;
2427       /* Fall through....  */
2428     case BIT_XOR_EXPR:
2429       /* This and MINUS_EXPR can be changed into a comparison of the
2430          two objects.  */
2431       if (TREE_TYPE (TREE_OPERAND (expr, 0))
2432           == TREE_TYPE (TREE_OPERAND (expr, 1)))
2433         return build_binary_op (NE_EXPR, TREE_OPERAND (expr, 0),
2434                                 TREE_OPERAND (expr, 1), 1);
2435       return build_binary_op (NE_EXPR, TREE_OPERAND (expr, 0),
2436                               fold (build1 (NOP_EXPR,
2437                                             TREE_TYPE (TREE_OPERAND (expr, 0)),
2438                                             TREE_OPERAND (expr, 1))), 1);
2439
2440     case BIT_AND_EXPR:
2441       if (integer_onep (TREE_OPERAND (expr, 1))
2442           && TREE_TYPE (expr) != truthvalue_type_node)
2443         /* Using convert here would cause infinite recursion.  */
2444         return build1 (NOP_EXPR, truthvalue_type_node, expr);
2445       break;
2446
2447     case MODIFY_EXPR:
2448       if (warn_parentheses && !TREE_NO_WARNING (expr))
2449         warning ("suggest parentheses around assignment used as truth value");
2450       break;
2451
2452     default:
2453       break;
2454     }
2455
2456   if (TREE_CODE (TREE_TYPE (expr)) == COMPLEX_TYPE)
2457     {
2458       tree t = save_expr (expr);
2459       return (build_binary_op
2460               ((TREE_SIDE_EFFECTS (expr)
2461                 ? TRUTH_OR_EXPR : TRUTH_ORIF_EXPR),
2462         lang_hooks.truthvalue_conversion (build_unary_op (REALPART_EXPR, t, 0)),
2463         lang_hooks.truthvalue_conversion (build_unary_op (IMAGPART_EXPR, t, 0)),
2464                0));
2465     }
2466
2467   return build_binary_op (NE_EXPR, expr, integer_zero_node, 1);
2468 }
2469 \f
2470 static tree builtin_function_2 (const char *builtin_name, const char *name,
2471                                 tree builtin_type, tree type,
2472                                 enum built_in_function function_code,
2473                                 enum built_in_class cl, int library_name_p,
2474                                 bool nonansi_p,
2475                                 tree attrs);
2476
2477 /* Make a variant type in the proper way for C/C++, propagating qualifiers
2478    down to the element type of an array.  */
2479
2480 tree
2481 c_build_qualified_type (tree type, int type_quals)
2482 {
2483   if (type == error_mark_node)
2484     return type;
2485
2486   if (TREE_CODE (type) == ARRAY_TYPE)
2487     return build_array_type (c_build_qualified_type (TREE_TYPE (type),
2488                                                      type_quals),
2489                              TYPE_DOMAIN (type));
2490
2491   /* A restrict-qualified pointer type must be a pointer to object or
2492      incomplete type.  Note that the use of POINTER_TYPE_P also allows
2493      REFERENCE_TYPEs, which is appropriate for C++.  */
2494   if ((type_quals & TYPE_QUAL_RESTRICT)
2495       && (!POINTER_TYPE_P (type)
2496           || !C_TYPE_OBJECT_OR_INCOMPLETE_P (TREE_TYPE (type))))
2497     {
2498       error ("invalid use of %<restrict%>");
2499       type_quals &= ~TYPE_QUAL_RESTRICT;
2500     }
2501
2502   return build_qualified_type (type, type_quals);
2503 }
2504
2505 /* Apply the TYPE_QUALS to the new DECL.  */
2506
2507 void
2508 c_apply_type_quals_to_decl (int type_quals, tree decl)
2509 {
2510   tree type = TREE_TYPE (decl);
2511
2512   if (type == error_mark_node)
2513     return;
2514
2515   if (((type_quals & TYPE_QUAL_CONST)
2516        || (type && TREE_CODE (type) == REFERENCE_TYPE))
2517       /* An object declared 'const' is only readonly after it is
2518          initialized.  We don't have any way of expressing this currently,
2519          so we need to be conservative and unset TREE_READONLY for types
2520          with constructors.  Otherwise aliasing code will ignore stores in
2521          an inline constructor.  */
2522       && !(type && TYPE_NEEDS_CONSTRUCTING (type)))
2523     TREE_READONLY (decl) = 1;
2524   if (type_quals & TYPE_QUAL_VOLATILE)
2525     {
2526       TREE_SIDE_EFFECTS (decl) = 1;
2527       TREE_THIS_VOLATILE (decl) = 1;
2528     }
2529   if (type_quals & TYPE_QUAL_RESTRICT)
2530     {
2531       while (type && TREE_CODE (type) == ARRAY_TYPE)
2532         /* Allow 'restrict' on arrays of pointers.
2533            FIXME currently we just ignore it.  */
2534         type = TREE_TYPE (type);
2535       if (!type
2536           || !POINTER_TYPE_P (type)
2537           || !C_TYPE_OBJECT_OR_INCOMPLETE_P (TREE_TYPE (type)))
2538         error ("invalid use of %<restrict%>");
2539       else if (flag_strict_aliasing && type == TREE_TYPE (decl))
2540         /* Indicate we need to make a unique alias set for this pointer.
2541            We can't do it here because it might be pointing to an
2542            incomplete type.  */
2543         DECL_POINTER_ALIAS_SET (decl) = -2;
2544     }
2545 }
2546
2547 /* Hash function for the problem of multiple type definitions in
2548    different files.  This must hash all types that will compare
2549    equal via comptypes to the same value.  In practice it hashes
2550    on some of the simple stuff and leaves the details to comptypes.  */
2551
2552 static hashval_t
2553 c_type_hash (const void *p)
2554 {
2555   int i = 0;
2556   int shift, size;
2557   tree t = (tree) p;
2558   tree t2;
2559   switch (TREE_CODE (t))
2560     {
2561     /* For pointers, hash on pointee type plus some swizzling.  */
2562     case POINTER_TYPE:
2563       return c_type_hash (TREE_TYPE (t)) ^ 0x3003003;
2564     /* Hash on number of elements and total size.  */
2565     case ENUMERAL_TYPE:
2566       shift = 3;
2567       t2 = TYPE_VALUES (t);
2568       break;
2569     case RECORD_TYPE:
2570       shift = 0;
2571       t2 = TYPE_FIELDS (t);
2572       break;
2573     case QUAL_UNION_TYPE:
2574       shift = 1;
2575       t2 = TYPE_FIELDS (t);
2576       break;
2577     case UNION_TYPE:
2578       shift = 2;
2579       t2 = TYPE_FIELDS (t);
2580       break;
2581     default:
2582       gcc_unreachable ();
2583     }
2584   for (; t2; t2 = TREE_CHAIN (t2))
2585     i++;
2586   size = TREE_INT_CST_LOW (TYPE_SIZE (t));
2587   return ((size << 24) | (i << shift));
2588 }
2589
2590 static GTY((param_is (union tree_node))) htab_t type_hash_table;
2591
2592 /* Return the typed-based alias set for T, which may be an expression
2593    or a type.  Return -1 if we don't do anything special.  */
2594
2595 HOST_WIDE_INT
2596 c_common_get_alias_set (tree t)
2597 {
2598   tree u;
2599   PTR *slot;
2600
2601   /* Permit type-punning when accessing a union, provided the access
2602      is directly through the union.  For example, this code does not
2603      permit taking the address of a union member and then storing
2604      through it.  Even the type-punning allowed here is a GCC
2605      extension, albeit a common and useful one; the C standard says
2606      that such accesses have implementation-defined behavior.  */
2607   for (u = t;
2608        TREE_CODE (u) == COMPONENT_REF || TREE_CODE (u) == ARRAY_REF;
2609        u = TREE_OPERAND (u, 0))
2610     if (TREE_CODE (u) == COMPONENT_REF
2611         && TREE_CODE (TREE_TYPE (TREE_OPERAND (u, 0))) == UNION_TYPE)
2612       return 0;
2613
2614   /* That's all the expressions we handle specially.  */
2615   if (!TYPE_P (t))
2616     return -1;
2617
2618   /* The C standard guarantees that any object may be accessed via an
2619      lvalue that has character type.  */
2620   if (t == char_type_node
2621       || t == signed_char_type_node
2622       || t == unsigned_char_type_node)
2623     return 0;
2624
2625   /* If it has the may_alias attribute, it can alias anything.  */
2626   if (lookup_attribute ("may_alias", TYPE_ATTRIBUTES (t)))
2627     return 0;
2628
2629   /* The C standard specifically allows aliasing between signed and
2630      unsigned variants of the same type.  We treat the signed
2631      variant as canonical.  */
2632   if (TREE_CODE (t) == INTEGER_TYPE && TYPE_UNSIGNED (t))
2633     {
2634       tree t1 = c_common_signed_type (t);
2635
2636       /* t1 == t can happen for boolean nodes which are always unsigned.  */
2637       if (t1 != t)
2638         return get_alias_set (t1);
2639     }
2640   else if (POINTER_TYPE_P (t))
2641     {
2642       tree t1;
2643
2644       /* Unfortunately, there is no canonical form of a pointer type.
2645          In particular, if we have `typedef int I', then `int *', and
2646          `I *' are different types.  So, we have to pick a canonical
2647          representative.  We do this below.
2648
2649          Technically, this approach is actually more conservative that
2650          it needs to be.  In particular, `const int *' and `int *'
2651          should be in different alias sets, according to the C and C++
2652          standard, since their types are not the same, and so,
2653          technically, an `int **' and `const int **' cannot point at
2654          the same thing.
2655
2656          But, the standard is wrong.  In particular, this code is
2657          legal C++:
2658
2659             int *ip;
2660             int **ipp = &ip;
2661             const int* const* cipp = ipp;
2662
2663          And, it doesn't make sense for that to be legal unless you
2664          can dereference IPP and CIPP.  So, we ignore cv-qualifiers on
2665          the pointed-to types.  This issue has been reported to the
2666          C++ committee.  */
2667       t1 = build_type_no_quals (t);
2668       if (t1 != t)
2669         return get_alias_set (t1);
2670     }
2671
2672   /* Handle the case of multiple type nodes referring to "the same" type,
2673      which occurs with IMA.  These share an alias set.  FIXME:  Currently only
2674      C90 is handled.  (In C99 type compatibility is not transitive, which
2675      complicates things mightily. The alias set splay trees can theoretically
2676      represent this, but insertion is tricky when you consider all the
2677      different orders things might arrive in.) */
2678
2679   if (c_language != clk_c || flag_isoc99)
2680     return -1;
2681
2682   /* Save time if there's only one input file.  */
2683   if (num_in_fnames == 1)
2684     return -1;
2685
2686   /* Pointers need special handling if they point to any type that
2687      needs special handling (below).  */
2688   if (TREE_CODE (t) == POINTER_TYPE)
2689     {
2690       tree t2;
2691       /* Find bottom type under any nested POINTERs.  */
2692       for (t2 = TREE_TYPE (t);
2693      TREE_CODE (t2) == POINTER_TYPE;
2694      t2 = TREE_TYPE (t2))
2695   ;
2696       if (TREE_CODE (t2) != RECORD_TYPE
2697     && TREE_CODE (t2) != ENUMERAL_TYPE
2698     && TREE_CODE (t2) != QUAL_UNION_TYPE
2699     && TREE_CODE (t2) != UNION_TYPE)
2700   return -1;
2701       if (TYPE_SIZE (t2) == 0)
2702   return -1;
2703     }
2704   /* These are the only cases that need special handling.  */
2705   if (TREE_CODE (t) != RECORD_TYPE
2706       && TREE_CODE (t) != ENUMERAL_TYPE
2707       && TREE_CODE (t) != QUAL_UNION_TYPE
2708       && TREE_CODE (t) != UNION_TYPE
2709       && TREE_CODE (t) != POINTER_TYPE)
2710     return -1;
2711   /* Undefined? */
2712   if (TYPE_SIZE (t) == 0)
2713     return -1;
2714
2715   /* Look up t in hash table.  Only one of the compatible types within each
2716      alias set is recorded in the table.  */
2717   if (!type_hash_table)
2718     type_hash_table = htab_create_ggc (1021, c_type_hash,
2719             (htab_eq) lang_hooks.types_compatible_p,
2720             NULL);
2721   slot = htab_find_slot (type_hash_table, t, INSERT);
2722   if (*slot != NULL)
2723     {
2724       TYPE_ALIAS_SET (t) = TYPE_ALIAS_SET ((tree)*slot);
2725       return TYPE_ALIAS_SET ((tree)*slot);
2726     }
2727   else
2728     /* Our caller will assign and record (in t) a new alias set; all we need
2729        to do is remember t in the hash table.  */
2730     *slot = t;
2731
2732   return -1;
2733 }
2734 \f
2735 /* Compute the value of 'sizeof (TYPE)' or '__alignof__ (TYPE)', where the
2736    second parameter indicates which OPERATOR is being applied.  The COMPLAIN
2737    flag controls whether we should diagnose possibly ill-formed
2738    constructs or not.  */
2739 tree
2740 c_sizeof_or_alignof_type (tree type, enum tree_code op, int complain)
2741 {
2742   const char *op_name;
2743   tree value = NULL;
2744   enum tree_code type_code = TREE_CODE (type);
2745
2746   gcc_assert (op == SIZEOF_EXPR || op == ALIGNOF_EXPR);
2747   op_name = op == SIZEOF_EXPR ? "sizeof" : "__alignof__";
2748
2749   if (type_code == FUNCTION_TYPE)
2750     {
2751       if (op == SIZEOF_EXPR)
2752         {
2753           if (complain && (pedantic || warn_pointer_arith))
2754             pedwarn ("invalid application of %<sizeof%> to a function type");
2755           value = size_one_node;
2756         }
2757       else
2758         value = size_int (FUNCTION_BOUNDARY / BITS_PER_UNIT);
2759     }
2760   else if (type_code == VOID_TYPE || type_code == ERROR_MARK)
2761     {
2762       if (type_code == VOID_TYPE
2763           && complain && (pedantic || warn_pointer_arith))
2764         pedwarn ("invalid application of %qs to a void type", op_name);
2765       value = size_one_node;
2766     }
2767   else if (!COMPLETE_TYPE_P (type))
2768     {
2769       if (complain)
2770         error ("invalid application of %qs to incomplete type %qT ",
2771                op_name, type);
2772       value = size_zero_node;
2773     }
2774   else
2775     {
2776       if (op == (enum tree_code) SIZEOF_EXPR)
2777         /* Convert in case a char is more than one unit.  */
2778         value = size_binop (CEIL_DIV_EXPR, TYPE_SIZE_UNIT (type),
2779                             size_int (TYPE_PRECISION (char_type_node)
2780                                       / BITS_PER_UNIT));
2781       else
2782         value = size_int (TYPE_ALIGN_UNIT (type));
2783     }
2784
2785   /* VALUE will have an integer type with TYPE_IS_SIZETYPE set.
2786      TYPE_IS_SIZETYPE means that certain things (like overflow) will
2787      never happen.  However, this node should really have type
2788      `size_t', which is just a typedef for an ordinary integer type.  */
2789   value = fold (build1 (NOP_EXPR, size_type_node, value));
2790   gcc_assert (!TYPE_IS_SIZETYPE (TREE_TYPE (value)));
2791
2792   return value;
2793 }
2794
2795 /* Implement the __alignof keyword: Return the minimum required
2796    alignment of EXPR, measured in bytes.  For VAR_DECL's and
2797    FIELD_DECL's return DECL_ALIGN (which can be set from an
2798    "aligned" __attribute__ specification).  */
2799
2800 tree
2801 c_alignof_expr (tree expr)
2802 {
2803   tree t;
2804
2805   if (TREE_CODE (expr) == VAR_DECL)
2806     t = size_int (DECL_ALIGN_UNIT (expr));
2807
2808   else if (TREE_CODE (expr) == COMPONENT_REF
2809            && DECL_C_BIT_FIELD (TREE_OPERAND (expr, 1)))
2810     {
2811       error ("%<__alignof%> applied to a bit-field");
2812       t = size_one_node;
2813     }
2814   else if (TREE_CODE (expr) == COMPONENT_REF
2815            && TREE_CODE (TREE_OPERAND (expr, 1)) == FIELD_DECL)
2816     t = size_int (DECL_ALIGN_UNIT (TREE_OPERAND (expr, 1)));
2817
2818   else if (TREE_CODE (expr) == INDIRECT_REF)
2819     {
2820       tree t = TREE_OPERAND (expr, 0);
2821       tree best = t;
2822       int bestalign = TYPE_ALIGN (TREE_TYPE (TREE_TYPE (t)));
2823
2824       while (TREE_CODE (t) == NOP_EXPR
2825              && TREE_CODE (TREE_TYPE (TREE_OPERAND (t, 0))) == POINTER_TYPE)
2826         {
2827           int thisalign;
2828
2829           t = TREE_OPERAND (t, 0);
2830           thisalign = TYPE_ALIGN (TREE_TYPE (TREE_TYPE (t)));
2831           if (thisalign > bestalign)
2832             best = t, bestalign = thisalign;
2833         }
2834       return c_alignof (TREE_TYPE (TREE_TYPE (best)));
2835     }
2836   else
2837     return c_alignof (TREE_TYPE (expr));
2838
2839   return fold (build1 (NOP_EXPR, size_type_node, t));
2840 }
2841 \f
2842 /* Handle C and C++ default attributes.  */
2843
2844 enum built_in_attribute
2845 {
2846 #define DEF_ATTR_NULL_TREE(ENUM) ENUM,
2847 #define DEF_ATTR_INT(ENUM, VALUE) ENUM,
2848 #define DEF_ATTR_IDENT(ENUM, STRING) ENUM,
2849 #define DEF_ATTR_TREE_LIST(ENUM, PURPOSE, VALUE, CHAIN) ENUM,
2850 #include "builtin-attrs.def"
2851 #undef DEF_ATTR_NULL_TREE
2852 #undef DEF_ATTR_INT
2853 #undef DEF_ATTR_IDENT
2854 #undef DEF_ATTR_TREE_LIST
2855   ATTR_LAST
2856 };
2857
2858 static GTY(()) tree built_in_attributes[(int) ATTR_LAST];
2859
2860 static void c_init_attributes (void);
2861
2862 /* Build tree nodes and builtin functions common to both C and C++ language
2863    frontends.  */
2864
2865 void
2866 c_common_nodes_and_builtins (void)
2867 {
2868   enum builtin_type
2869   {
2870 #define DEF_PRIMITIVE_TYPE(NAME, VALUE) NAME,
2871 #define DEF_FUNCTION_TYPE_0(NAME, RETURN) NAME,
2872 #define DEF_FUNCTION_TYPE_1(NAME, RETURN, ARG1) NAME,
2873 #define DEF_FUNCTION_TYPE_2(NAME, RETURN, ARG1, ARG2) NAME,
2874 #define DEF_FUNCTION_TYPE_3(NAME, RETURN, ARG1, ARG2, ARG3) NAME,
2875 #define DEF_FUNCTION_TYPE_4(NAME, RETURN, ARG1, ARG2, ARG3, ARG4) NAME,
2876 #define DEF_FUNCTION_TYPE_VAR_0(NAME, RETURN) NAME,
2877 #define DEF_FUNCTION_TYPE_VAR_1(NAME, RETURN, ARG1) NAME,
2878 #define DEF_FUNCTION_TYPE_VAR_2(NAME, RETURN, ARG1, ARG2) NAME,
2879 #define DEF_FUNCTION_TYPE_VAR_3(NAME, RETURN, ARG1, ARG2, ARG3) NAME,
2880 #define DEF_POINTER_TYPE(NAME, TYPE) NAME,
2881 #include "builtin-types.def"
2882 #undef DEF_PRIMITIVE_TYPE
2883 #undef DEF_FUNCTION_TYPE_0
2884 #undef DEF_FUNCTION_TYPE_1
2885 #undef DEF_FUNCTION_TYPE_2
2886 #undef DEF_FUNCTION_TYPE_3
2887 #undef DEF_FUNCTION_TYPE_4
2888 #undef DEF_FUNCTION_TYPE_VAR_0
2889 #undef DEF_FUNCTION_TYPE_VAR_1
2890 #undef DEF_FUNCTION_TYPE_VAR_2
2891 #undef DEF_FUNCTION_TYPE_VAR_3
2892 #undef DEF_POINTER_TYPE
2893     BT_LAST
2894   };
2895
2896   typedef enum builtin_type builtin_type;
2897
2898   tree builtin_types[(int) BT_LAST];
2899   int wchar_type_size;
2900   tree array_domain_type;
2901   tree va_list_ref_type_node;
2902   tree va_list_arg_type_node;
2903
2904   /* Define `int' and `char' first so that dbx will output them first.  */
2905   record_builtin_type (RID_INT, NULL, integer_type_node);
2906   record_builtin_type (RID_CHAR, "char", char_type_node);
2907
2908   /* `signed' is the same as `int'.  FIXME: the declarations of "signed",
2909      "unsigned long", "long long unsigned" and "unsigned short" were in C++
2910      but not C.  Are the conditionals here needed?  */
2911   if (c_dialect_cxx ())
2912     record_builtin_type (RID_SIGNED, NULL, integer_type_node);
2913   record_builtin_type (RID_LONG, "long int", long_integer_type_node);
2914   record_builtin_type (RID_UNSIGNED, "unsigned int", unsigned_type_node);
2915   record_builtin_type (RID_MAX, "long unsigned int",
2916                        long_unsigned_type_node);
2917   if (c_dialect_cxx ())
2918     record_builtin_type (RID_MAX, "unsigned long", long_unsigned_type_node);
2919   record_builtin_type (RID_MAX, "long long int",
2920                        long_long_integer_type_node);
2921   record_builtin_type (RID_MAX, "long long unsigned int",
2922                        long_long_unsigned_type_node);
2923   if (c_dialect_cxx ())
2924     record_builtin_type (RID_MAX, "long long unsigned",
2925                          long_long_unsigned_type_node);
2926   record_builtin_type (RID_SHORT, "short int", short_integer_type_node);
2927   record_builtin_type (RID_MAX, "short unsigned int",
2928                        short_unsigned_type_node);
2929   if (c_dialect_cxx ())
2930     record_builtin_type (RID_MAX, "unsigned short",
2931                          short_unsigned_type_node);
2932
2933   /* Define both `signed char' and `unsigned char'.  */
2934   record_builtin_type (RID_MAX, "signed char", signed_char_type_node);
2935   record_builtin_type (RID_MAX, "unsigned char", unsigned_char_type_node);
2936
2937   /* These are types that c_common_type_for_size and
2938      c_common_type_for_mode use.  */
2939   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
2940                                          intQI_type_node));
2941   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
2942                                          intHI_type_node));
2943   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
2944                                          intSI_type_node));
2945   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
2946                                          intDI_type_node));
2947 #if HOST_BITS_PER_WIDE_INT >= 64
2948   if (targetm.scalar_mode_supported_p (TImode))
2949     lang_hooks.decls.pushdecl (build_decl (TYPE_DECL,
2950                                            get_identifier ("__int128_t"),
2951                                            intTI_type_node));
2952 #endif
2953   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
2954                                          unsigned_intQI_type_node));
2955   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
2956                                          unsigned_intHI_type_node));
2957   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
2958                                          unsigned_intSI_type_node));
2959   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
2960                                          unsigned_intDI_type_node));
2961 #if HOST_BITS_PER_WIDE_INT >= 64
2962   if (targetm.scalar_mode_supported_p (TImode))
2963     lang_hooks.decls.pushdecl (build_decl (TYPE_DECL,
2964                                            get_identifier ("__uint128_t"),
2965                                            unsigned_intTI_type_node));
2966 #endif
2967
2968   /* Create the widest literal types.  */
2969   widest_integer_literal_type_node
2970     = make_signed_type (HOST_BITS_PER_WIDE_INT * 2);
2971   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
2972                                          widest_integer_literal_type_node));
2973
2974   widest_unsigned_literal_type_node
2975     = make_unsigned_type (HOST_BITS_PER_WIDE_INT * 2);
2976   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL, NULL_TREE,
2977                                          widest_unsigned_literal_type_node));
2978
2979   /* `unsigned long' is the standard type for sizeof.
2980      Note that stddef.h uses `unsigned long',
2981      and this must agree, even if long and int are the same size.  */
2982   size_type_node =
2983     TREE_TYPE (identifier_global_value (get_identifier (SIZE_TYPE)));
2984   signed_size_type_node = c_common_signed_type (size_type_node);
2985   set_sizetype (size_type_node);
2986
2987   pid_type_node =
2988     TREE_TYPE (identifier_global_value (get_identifier (PID_TYPE)));
2989
2990   build_common_tree_nodes_2 (flag_short_double);
2991
2992   record_builtin_type (RID_FLOAT, NULL, float_type_node);
2993   record_builtin_type (RID_DOUBLE, NULL, double_type_node);
2994   record_builtin_type (RID_MAX, "long double", long_double_type_node);
2995
2996   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL,
2997                                          get_identifier ("complex int"),
2998                                          complex_integer_type_node));
2999   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL,
3000                                          get_identifier ("complex float"),
3001                                          complex_float_type_node));
3002   lang_hooks.decls.pushdecl (build_decl (TYPE_DECL,
3003                                          get_identifier ("complex double"),
3004                                          complex_double_type_node));
3005   lang_hooks.decls.pushdecl
3006     (build_decl (TYPE_DECL, get_identifier ("complex long double"),
3007                  complex_long_double_type_node));
3008
3009   if (c_dialect_cxx ())
3010     /* For C++, make fileptr_type_node a distinct void * type until
3011        FILE type is defined.  */
3012     fileptr_type_node = build_variant_type_copy (ptr_type_node);
3013
3014   record_builtin_type (RID_VOID, NULL, void_type_node);
3015
3016   /* This node must not be shared.  */
3017   void_zero_node = make_node (INTEGER_CST);
3018   TREE_TYPE (void_zero_node) = void_type_node;
3019
3020   void_list_node = build_void_list_node ();
3021
3022   /* Make a type to be the domain of a few array types
3023      whose domains don't really matter.
3024      200 is small enough that it always fits in size_t
3025      and large enough that it can hold most function names for the
3026      initializations of __FUNCTION__ and __PRETTY_FUNCTION__.  */
3027   array_domain_type = build_index_type (size_int (200));
3028
3029   /* Make a type for arrays of characters.
3030      With luck nothing will ever really depend on the length of this
3031      array type.  */
3032   char_array_type_node
3033     = build_array_type (char_type_node, array_domain_type);
3034
3035   /* Likewise for arrays of ints.  */
3036   int_array_type_node
3037     = build_array_type (integer_type_node, array_domain_type);
3038
3039   string_type_node = build_pointer_type (char_type_node);
3040   const_string_type_node
3041     = build_pointer_type (build_qualified_type
3042                           (char_type_node, TYPE_QUAL_CONST));
3043
3044   /* This is special for C++ so functions can be overloaded.  */
3045   wchar_type_node = get_identifier (MODIFIED_WCHAR_TYPE);
3046   wchar_type_node = TREE_TYPE (identifier_global_value (wchar_type_node));
3047   wchar_type_size = TYPE_PRECISION (wchar_type_node);
3048   if (c_dialect_cxx ())
3049     {
3050       if (TYPE_UNSIGNED (wchar_type_node))
3051         wchar_type_node = make_unsigned_type (wchar_type_size);
3052       else
3053         wchar_type_node = make_signed_type (wchar_type_size);
3054       record_builtin_type (RID_WCHAR, "wchar_t", wchar_type_node);
3055     }
3056   else
3057     {
3058       signed_wchar_type_node = c_common_signed_type (wchar_type_node);
3059       unsigned_wchar_type_node = c_common_unsigned_type (wchar_type_node);
3060     }
3061
3062   /* This is for wide string constants.  */
3063   wchar_array_type_node
3064     = build_array_type (wchar_type_node, array_domain_type);
3065
3066   wint_type_node =
3067     TREE_TYPE (identifier_global_value (get_identifier (WINT_TYPE)));
3068
3069   intmax_type_node =
3070     TREE_TYPE (identifier_global_value (get_identifier (INTMAX_TYPE)));
3071   uintmax_type_node =
3072     TREE_TYPE (identifier_global_value (get_identifier (UINTMAX_TYPE)));
3073
3074   default_function_type = build_function_type (integer_type_node, NULL_TREE);
3075   ptrdiff_type_node
3076     = TREE_TYPE (identifier_global_value (get_identifier (PTRDIFF_TYPE)));
3077   unsigned_ptrdiff_type_node = c_common_unsigned_type (ptrdiff_type_node);
3078
3079   lang_hooks.decls.pushdecl
3080     (build_decl (TYPE_DECL, get_identifier ("__builtin_va_list"),
3081                  va_list_type_node));
3082
3083   if (TREE_CODE (va_list_type_node) == ARRAY_TYPE)
3084     {
3085       va_list_arg_type_node = va_list_ref_type_node =
3086         build_pointer_type (TREE_TYPE (va_list_type_node));
3087     }
3088   else
3089     {
3090       va_list_arg_type_node = va_list_type_node;
3091       va_list_ref_type_node = build_reference_type (va_list_type_node);
3092     }
3093
3094 #define DEF_PRIMITIVE_TYPE(ENUM, VALUE) \
3095   builtin_types[(int) ENUM] = VALUE;
3096 #define DEF_FUNCTION_TYPE_0(ENUM, RETURN)               \
3097   builtin_types[(int) ENUM]                             \
3098     = build_function_type (builtin_types[(int) RETURN], \
3099                            void_list_node);
3100 #define DEF_FUNCTION_TYPE_1(ENUM, RETURN, ARG1)                         \
3101   builtin_types[(int) ENUM]                                             \
3102     = build_function_type (builtin_types[(int) RETURN],                 \
3103                            tree_cons (NULL_TREE,                        \
3104                                       builtin_types[(int) ARG1],        \
3105                                       void_list_node));
3106 #define DEF_FUNCTION_TYPE_2(ENUM, RETURN, ARG1, ARG2)   \
3107   builtin_types[(int) ENUM]                             \
3108     = build_function_type                               \
3109       (builtin_types[(int) RETURN],                     \
3110        tree_cons (NULL_TREE,                            \
3111                   builtin_types[(int) ARG1],            \
3112                   tree_cons (NULL_TREE,                 \
3113                              builtin_types[(int) ARG2], \
3114                              void_list_node)));
3115 #define DEF_FUNCTION_TYPE_3(ENUM, RETURN, ARG1, ARG2, ARG3)              \
3116   builtin_types[(int) ENUM]                                              \
3117     = build_function_type                                                \
3118       (builtin_types[(int) RETURN],                                      \
3119        tree_cons (NULL_TREE,                                             \
3120                   builtin_types[(int) ARG1],                             \
3121                   tree_cons (NULL_TREE,                                  \
3122                              builtin_types[(int) ARG2],                  \
3123                              tree_cons (NULL_TREE,                       \
3124                                         builtin_types[(int) ARG3],       \
3125                                         void_list_node))));
3126 #define DEF_FUNCTION_TYPE_4(ENUM, RETURN, ARG1, ARG2, ARG3, ARG4)       \
3127   builtin_types[(int) ENUM]                                             \
3128     = build_function_type                                               \
3129       (builtin_types[(int) RETURN],                                     \
3130        tree_cons (NULL_TREE,                                            \
3131                   builtin_types[(int) ARG1],                            \
3132                   tree_cons (NULL_TREE,                                 \
3133                              builtin_types[(int) ARG2],                 \
3134                              tree_cons                                  \
3135                              (NULL_TREE,                                \
3136                               builtin_types[(int) ARG3],                \
3137                               tree_cons (NULL_TREE,                     \
3138                                          builtin_types[(int) ARG4],     \
3139                                          void_list_node)))));
3140 #define DEF_FUNCTION_TYPE_VAR_0(ENUM, RETURN)                           \
3141   builtin_types[(int) ENUM]                                             \
3142     = build_function_type (builtin_types[(int) RETURN], NULL_TREE);
3143 #define DEF_FUNCTION_TYPE_VAR_1(ENUM, RETURN, ARG1)                      \
3144    builtin_types[(int) ENUM]                                             \
3145     = build_function_type (builtin_types[(int) RETURN],          \
3146                            tree_cons (NULL_TREE,                         \
3147                                       builtin_types[(int) ARG1],         \
3148                                       NULL_TREE));
3149
3150 #define DEF_FUNCTION_TYPE_VAR_2(ENUM, RETURN, ARG1, ARG2)       \
3151    builtin_types[(int) ENUM]                                    \
3152     = build_function_type                                       \
3153       (builtin_types[(int) RETURN],                             \
3154        tree_cons (NULL_TREE,                                    \
3155                   builtin_types[(int) ARG1],                    \
3156                   tree_cons (NULL_TREE,                         \
3157                              builtin_types[(int) ARG2],         \
3158                              NULL_TREE)));
3159
3160 #define DEF_FUNCTION_TYPE_VAR_3(ENUM, RETURN, ARG1, ARG2, ARG3)         \
3161    builtin_types[(int) ENUM]                                            \
3162     = build_function_type                                               \
3163       (builtin_types[(int) RETURN],                                     \
3164        tree_cons (NULL_TREE,                                            \
3165                   builtin_types[(int) ARG1],                            \
3166                   tree_cons (NULL_TREE,                                 \
3167                              builtin_types[(int) ARG2],                 \
3168                              tree_cons (NULL_TREE,                      \
3169                                         builtin_types[(int) ARG3],      \
3170                                         NULL_TREE))));
3171
3172 #define DEF_POINTER_TYPE(ENUM, TYPE)                    \
3173   builtin_types[(int) ENUM]                             \
3174     = build_pointer_type (builtin_types[(int) TYPE]);
3175 #include "builtin-types.def"
3176 #undef DEF_PRIMITIVE_TYPE
3177 #undef DEF_FUNCTION_TYPE_1
3178 #undef DEF_FUNCTION_TYPE_2
3179 #undef DEF_FUNCTION_TYPE_3
3180 #undef DEF_FUNCTION_TYPE_4
3181 #undef DEF_FUNCTION_TYPE_VAR_0
3182 #undef DEF_FUNCTION_TYPE_VAR_1
3183 #undef DEF_FUNCTION_TYPE_VAR_2
3184 #undef DEF_FUNCTION_TYPE_VAR_3
3185 #undef DEF_POINTER_TYPE
3186
3187   c_init_attributes ();
3188
3189 #define DEF_BUILTIN(ENUM, NAME, CLASS, TYPE, LIBTYPE,                   \
3190                     BOTH_P, FALLBACK_P, NONANSI_P, ATTRS, IMPLICIT)     \
3191   if (NAME)                                                             \
3192     {                                                                   \
3193       tree decl;                                                        \
3194                                                                         \
3195       gcc_assert (!strncmp (NAME, "__builtin_",                         \
3196                             strlen ("__builtin_")));                    \
3197                                                                         \
3198       if (!BOTH_P)                                                      \
3199         decl = lang_hooks.builtin_function (NAME, builtin_types[TYPE],  \
3200                                  ENUM,                                  \
3201                                  CLASS,                                 \
3202                                  (FALLBACK_P                            \
3203                                   ? (NAME + strlen ("__builtin_"))      \
3204                                   : NULL),                              \
3205                                  built_in_attributes[(int) ATTRS]);     \
3206       else                                                              \
3207         decl = builtin_function_2 (NAME,                                \
3208                                    NAME + strlen ("__builtin_"),        \
3209                                    builtin_types[TYPE],                 \
3210                                    builtin_types[LIBTYPE],              \
3211                                    ENUM,                                \
3212                                    CLASS,                               \
3213                                    FALLBACK_P,                          \
3214                                    NONANSI_P,                           \
3215                                    built_in_attributes[(int) ATTRS]);   \
3216                                                                         \
3217       built_in_decls[(int) ENUM] = decl;                                \
3218       if (IMPLICIT)                                                     \
3219         implicit_built_in_decls[(int) ENUM] = decl;                     \
3220     }
3221 #include "builtins.def"
3222 #undef DEF_BUILTIN
3223
3224   targetm.init_builtins ();
3225   if (flag_mudflap)
3226     mudflap_init ();
3227
3228   main_identifier_node = get_identifier ("main");
3229 }
3230
3231 tree
3232 build_va_arg (tree expr, tree type)
3233 {
3234   return build1 (VA_ARG_EXPR, type, expr);
3235 }
3236
3237
3238 /* Linked list of disabled built-in functions.  */
3239
3240 typedef struct disabled_builtin
3241 {
3242   const char *name;
3243   struct disabled_builtin *next;
3244 } disabled_builtin;
3245 static disabled_builtin *disabled_builtins = NULL;
3246
3247 static bool builtin_function_disabled_p (const char *);
3248
3249 /* Disable a built-in function specified by -fno-builtin-NAME.  If NAME
3250    begins with "__builtin_", give an error.  */
3251
3252 void
3253 disable_builtin_function (const char *name)
3254 {
3255   if (strncmp (name, "__builtin_", strlen ("__builtin_")) == 0)
3256     error ("cannot disable built-in function %qs", name);
3257   else
3258     {
3259       disabled_builtin *new_disabled_builtin = XNEW (disabled_builtin);
3260       new_disabled_builtin->name = name;
3261       new_disabled_builtin->next = disabled_builtins;
3262       disabled_builtins = new_disabled_builtin;
3263     }
3264 }
3265
3266
3267 /* Return true if the built-in function NAME has been disabled, false
3268    otherwise.  */
3269
3270 static bool
3271 builtin_function_disabled_p (const char *name)
3272 {
3273   disabled_builtin *p;
3274   for (p = disabled_builtins; p != NULL; p = p->next)
3275     {
3276       if (strcmp (name, p->name) == 0)
3277         return true;
3278     }
3279   return false;
3280 }
3281
3282
3283 /* Possibly define a builtin function with one or two names.  BUILTIN_NAME
3284    is an __builtin_-prefixed name; NAME is the ordinary name; one or both
3285    of these may be NULL (though both being NULL is useless).
3286    BUILTIN_TYPE is the type of the __builtin_-prefixed function;
3287    TYPE is the type of the function with the ordinary name.  These
3288    may differ if the ordinary name is declared with a looser type to avoid
3289    conflicts with headers.  FUNCTION_CODE and CL are as for
3290    builtin_function.  If LIBRARY_NAME_P is nonzero, NAME is passed as
3291    the LIBRARY_NAME parameter to builtin_function when declaring BUILTIN_NAME.
3292    If NONANSI_P is true, the name NAME is treated as a non-ANSI name;
3293    ATTRS is the tree list representing the builtin's function attributes.
3294    Returns the declaration of BUILTIN_NAME, if any, otherwise
3295    the declaration of NAME.  Does not declare NAME if flag_no_builtin,
3296    or if NONANSI_P and flag_no_nonansi_builtin.  */
3297
3298 static tree
3299 builtin_function_2 (const char *builtin_name, const char *name,
3300                     tree builtin_type, tree type,
3301                     enum built_in_function function_code,
3302                     enum built_in_class cl, int library_name_p,
3303                     bool nonansi_p, tree attrs)
3304 {
3305   tree bdecl = NULL_TREE;
3306   tree decl = NULL_TREE;
3307
3308   if (builtin_name != 0)
3309     bdecl = lang_hooks.builtin_function (builtin_name, builtin_type,
3310                                          function_code, cl,
3311                                          library_name_p ? name : NULL, attrs);
3312
3313   if (name != 0 && !flag_no_builtin && !builtin_function_disabled_p (name)
3314       && !(nonansi_p && flag_no_nonansi_builtin))
3315     decl = lang_hooks.builtin_function (name, type, function_code, cl,
3316                                         NULL, attrs);
3317
3318   return (bdecl != 0 ? bdecl : decl);
3319 }
3320 \f
3321 /* Nonzero if the type T promotes to int.  This is (nearly) the
3322    integral promotions defined in ISO C99 6.3.1.1/2.  */
3323
3324 bool
3325 c_promoting_integer_type_p (tree t)
3326 {
3327   switch (TREE_CODE (t))
3328     {
3329     case INTEGER_TYPE:
3330       return (TYPE_MAIN_VARIANT (t) == char_type_node
3331               || TYPE_MAIN_VARIANT (t) == signed_char_type_node
3332               || TYPE_MAIN_VARIANT (t) == unsigned_char_type_node
3333               || TYPE_MAIN_VARIANT (t) == short_integer_type_node
3334               || TYPE_MAIN_VARIANT (t) == short_unsigned_type_node
3335               || TYPE_PRECISION (t) < TYPE_PRECISION (integer_type_node));
3336
3337     case ENUMERAL_TYPE:
3338       /* ??? Technically all enumerations not larger than an int
3339          promote to an int.  But this is used along code paths
3340          that only want to notice a size change.  */
3341       return TYPE_PRECISION (t) < TYPE_PRECISION (integer_type_node);
3342
3343     case BOOLEAN_TYPE:
3344       return 1;
3345
3346     default:
3347       return 0;
3348     }
3349 }
3350
3351 /* Return 1 if PARMS specifies a fixed number of parameters
3352    and none of their types is affected by default promotions.  */
3353
3354 int
3355 self_promoting_args_p (tree parms)
3356 {
3357   tree t;
3358   for (t = parms; t; t = TREE_CHAIN (t))
3359     {
3360       tree type = TREE_VALUE (t);
3361
3362       if (TREE_CHAIN (t) == 0 && type != void_type_node)
3363         return 0;
3364
3365       if (type == 0)
3366         return 0;
3367
3368       if (TYPE_MAIN_VARIANT (type) == float_type_node)
3369         return 0;
3370
3371       if (c_promoting_integer_type_p (type))
3372         return 0;
3373     }
3374   return 1;
3375 }
3376
3377 /* Recursively examines the array elements of TYPE, until a non-array
3378    element type is found.  */
3379
3380 tree
3381 strip_array_types (tree type)
3382 {
3383   while (TREE_CODE (type) == ARRAY_TYPE)
3384     type = TREE_TYPE (type);
3385
3386   return type;
3387 }
3388
3389 /* Recursively remove any '*' or '&' operator from TYPE.  */
3390 tree
3391 strip_pointer_operator (tree t)
3392 {
3393   while (POINTER_TYPE_P (t))
3394     t = TREE_TYPE (t);
3395   return t;
3396 }
3397
3398 /* Used to compare case labels.  K1 and K2 are actually tree nodes
3399    representing case labels, or NULL_TREE for a `default' label.
3400    Returns -1 if K1 is ordered before K2, -1 if K1 is ordered after
3401    K2, and 0 if K1 and K2 are equal.  */
3402
3403 int
3404 case_compare (splay_tree_key k1, splay_tree_key k2)
3405 {
3406   /* Consider a NULL key (such as arises with a `default' label) to be
3407      smaller than anything else.  */
3408   if (!k1)
3409     return k2 ? -1 : 0;
3410   else if (!k2)
3411     return k1 ? 1 : 0;
3412
3413   return tree_int_cst_compare ((tree) k1, (tree) k2);
3414 }
3415
3416 /* Process a case label for the range LOW_VALUE ... HIGH_VALUE.  If
3417    LOW_VALUE and HIGH_VALUE are both NULL_TREE then this case label is
3418    actually a `default' label.  If only HIGH_VALUE is NULL_TREE, then
3419    case label was declared using the usual C/C++ syntax, rather than
3420    the GNU case range extension.  CASES is a tree containing all the
3421    case ranges processed so far; COND is the condition for the
3422    switch-statement itself.  Returns the CASE_LABEL_EXPR created, or
3423    ERROR_MARK_NODE if no CASE_LABEL_EXPR is created.  */
3424
3425 tree
3426 c_add_case_label (splay_tree cases, tree cond, tree orig_type,
3427                   tree low_value, tree high_value)
3428 {
3429   tree type;
3430   tree label;
3431   tree case_label;
3432   splay_tree_node node;
3433
3434   /* Create the LABEL_DECL itself.  */
3435   label = create_artificial_label ();
3436
3437   /* If there was an error processing the switch condition, bail now
3438      before we get more confused.  */
3439   if (!cond || cond == error_mark_node)
3440     goto error_out;
3441
3442   if ((low_value && TREE_TYPE (low_value)
3443        && POINTER_TYPE_P (TREE_TYPE (low_value)))
3444       || (high_value && TREE_TYPE (high_value)
3445           && POINTER_TYPE_P (TREE_TYPE (high_value))))
3446     error ("pointers are not permitted as case values");
3447
3448   /* Case ranges are a GNU extension.  */
3449   if (high_value && pedantic)
3450     pedwarn ("range expressions in switch statements are non-standard");
3451
3452   type = TREE_TYPE (cond);
3453   if (low_value)
3454     {
3455       low_value = check_case_value (low_value);
3456       low_value = convert_and_check (type, low_value);
3457     }
3458   if (high_value)
3459     {
3460       high_value = check_case_value (high_value);
3461       high_value = convert_and_check (type, high_value);
3462     }
3463
3464   /* If an error has occurred, bail out now.  */
3465   if (low_value == error_mark_node || high_value == error_mark_node)
3466     goto error_out;
3467
3468   /* If the LOW_VALUE and HIGH_VALUE are the same, then this isn't
3469      really a case range, even though it was written that way.  Remove
3470      the HIGH_VALUE to simplify later processing.  */
3471   if (tree_int_cst_equal (low_value, high_value))
3472     high_value = NULL_TREE;
3473   if (low_value && high_value
3474       && !tree_int_cst_lt (low_value, high_value))
3475     warning ("empty range specified");
3476
3477   /* See if the case is in range of the type of the original testing
3478      expression.  If both low_value and high_value are out of range,
3479      don't insert the case label and return NULL_TREE.  */
3480   if (low_value
3481       && !check_case_bounds (type, orig_type,
3482                              &low_value, high_value ? &high_value : NULL))
3483     return NULL_TREE;
3484
3485   /* Look up the LOW_VALUE in the table of case labels we already
3486      have.  */
3487   node = splay_tree_lookup (cases, (splay_tree_key) low_value);
3488   /* If there was not an exact match, check for overlapping ranges.
3489      There's no need to do this if there's no LOW_VALUE or HIGH_VALUE;
3490      that's a `default' label and the only overlap is an exact match.  */
3491   if (!node && (low_value || high_value))
3492     {
3493       splay_tree_node low_bound;
3494       splay_tree_node high_bound;
3495
3496       /* Even though there wasn't an exact match, there might be an
3497          overlap between this case range and another case range.
3498          Since we've (inductively) not allowed any overlapping case
3499          ranges, we simply need to find the greatest low case label
3500          that is smaller that LOW_VALUE, and the smallest low case
3501          label that is greater than LOW_VALUE.  If there is an overlap
3502          it will occur in one of these two ranges.  */
3503       low_bound = splay_tree_predecessor (cases,
3504                                           (splay_tree_key) low_value);
3505       high_bound = splay_tree_successor (cases,
3506                                          (splay_tree_key) low_value);
3507
3508       /* Check to see if the LOW_BOUND overlaps.  It is smaller than
3509          the LOW_VALUE, so there is no need to check unless the
3510          LOW_BOUND is in fact itself a case range.  */
3511       if (low_bound
3512           && CASE_HIGH ((tree) low_bound->value)
3513           && tree_int_cst_compare (CASE_HIGH ((tree) low_bound->value),
3514                                     low_value) >= 0)
3515         node = low_bound;
3516       /* Check to see if the HIGH_BOUND overlaps.  The low end of that
3517          range is bigger than the low end of the current range, so we
3518          are only interested if the current range is a real range, and
3519          not an ordinary case label.  */
3520       else if (high_bound
3521                && high_value
3522                && (tree_int_cst_compare ((tree) high_bound->key,
3523                                          high_value)
3524                    <= 0))
3525         node = high_bound;
3526     }
3527   /* If there was an overlap, issue an error.  */
3528   if (node)
3529     {
3530       tree duplicate = CASE_LABEL ((tree) node->value);
3531
3532       if (high_value)
3533         {
3534           error ("duplicate (or overlapping) case value");
3535           error ("%Jthis is the first entry overlapping that value", duplicate);
3536         }
3537       else if (low_value)
3538         {
3539           error ("duplicate case value") ;
3540           error ("%Jpreviously used here", duplicate);
3541         }
3542       else
3543         {
3544           error ("multiple default labels in one switch");
3545           error ("%Jthis is the first default label", duplicate);
3546         }
3547       goto error_out;
3548     }
3549
3550   /* Add a CASE_LABEL to the statement-tree.  */
3551   case_label = add_stmt (build_case_label (low_value, high_value, label));
3552   /* Register this case label in the splay tree.  */
3553   splay_tree_insert (cases,
3554                      (splay_tree_key) low_value,
3555                      (splay_tree_value) case_label);
3556
3557   return case_label;
3558
3559  error_out:
3560   /* Add a label so that the back-end doesn't think that the beginning of
3561      the switch is unreachable.  Note that we do not add a case label, as
3562      that just leads to duplicates and thence to aborts later on.  */
3563   if (!cases->root)
3564     {
3565       tree t = create_artificial_label ();
3566       add_stmt (build_stmt (LABEL_EXPR, t));
3567     }
3568   return error_mark_node;
3569 }
3570
3571 /* Subroutines of c_do_switch_warnings, called via splay_tree_foreach.
3572    Used to verify that case values match up with enumerator values.  */
3573
3574 static void
3575 match_case_to_enum_1 (tree key, tree type, tree label)
3576 {
3577   char buf[2 + 2*HOST_BITS_PER_WIDE_INT/4 + 1];
3578
3579   /* ??? Not working too hard to print the double-word value.
3580      Should perhaps be done with %lwd in the diagnostic routines?  */
3581   if (TREE_INT_CST_HIGH (key) == 0)
3582     snprintf (buf, sizeof (buf), HOST_WIDE_INT_PRINT_UNSIGNED,
3583               TREE_INT_CST_LOW (key));
3584   else if (!TYPE_UNSIGNED (type)
3585            && TREE_INT_CST_HIGH (key) == -1
3586            && TREE_INT_CST_LOW (key) != 0)
3587     snprintf (buf, sizeof (buf), "-" HOST_WIDE_INT_PRINT_UNSIGNED,
3588               -TREE_INT_CST_LOW (key));
3589   else
3590     snprintf (buf, sizeof (buf), HOST_WIDE_INT_PRINT_DOUBLE_HEX,
3591               TREE_INT_CST_HIGH (key), TREE_INT_CST_LOW (key));
3592
3593   if (TYPE_NAME (type) == 0)
3594     warning ("%Jcase value %qs not in enumerated type",
3595              CASE_LABEL (label), buf);
3596   else
3597     warning ("%Jcase value %qs not in enumerated type %qT",
3598              CASE_LABEL (label), buf, type);
3599 }
3600
3601 static int
3602 match_case_to_enum (splay_tree_node node, void *data)
3603 {
3604   tree label = (tree) node->value;
3605   tree type = (tree) data;
3606
3607   /* Skip default case.  */
3608   if (!CASE_LOW (label))
3609     return 0;
3610
3611   /* If TREE_ADDRESSABLE is not set, that means CASE_LOW did not appear
3612      when we did our enum->case scan.  Reset our scratch bit after.  */
3613   if (!TREE_ADDRESSABLE (label))
3614     match_case_to_enum_1 (CASE_LOW (label), type, label);
3615   else
3616     TREE_ADDRESSABLE (label) = 0;
3617
3618   /* If CASE_HIGH is non-null, we have a range.  Here we must search.
3619      Note that the old code in stmt.c did not check for the values in
3620      the range either, just the endpoints.  */
3621   if (CASE_HIGH (label))
3622     {
3623       tree chain, key = CASE_HIGH (label);
3624
3625       for (chain = TYPE_VALUES (type);
3626            chain && !tree_int_cst_equal (key, TREE_VALUE (chain));
3627            chain = TREE_CHAIN (chain))
3628         continue;
3629       if (!chain)
3630         match_case_to_enum_1 (key, type, label);
3631     }
3632
3633   return 0;
3634 }
3635
3636 /* Handle -Wswitch*.  Called from the front end after parsing the switch
3637    construct.  */
3638 /* ??? Should probably be somewhere generic, since other languages besides
3639    C and C++ would want this.  We'd want to agree on the datastructure,
3640    however, which is a problem.  Alternately, we operate on gimplified
3641    switch_exprs, which I don't especially like.  At the moment, however,
3642    C/C++ are the only tree-ssa languages that support enumerations at all,
3643    so the point is moot.  */
3644
3645 void
3646 c_do_switch_warnings (splay_tree cases, tree switch_stmt)
3647 {
3648   splay_tree_node default_node;
3649   location_t switch_location;
3650   tree type;
3651
3652   if (!warn_switch && !warn_switch_enum && !warn_switch_default)
3653     return;
3654
3655   if (EXPR_HAS_LOCATION (switch_stmt))
3656     switch_location = EXPR_LOCATION (switch_stmt);
3657   else
3658     switch_location = input_location;
3659
3660   type = SWITCH_TYPE (switch_stmt);
3661
3662   default_node = splay_tree_lookup (cases, (splay_tree_key) NULL);
3663   if (warn_switch_default && !default_node)
3664     warning ("%Hswitch missing default case", &switch_location);
3665
3666   /* If the switch expression was an enumerated type, check that
3667      exactly all enumeration literals are covered by the cases.
3668      The check is made when -Wswitch was specified and there is no
3669      default case, or when -Wswitch-enum was specified.  */
3670   if (((warn_switch && !default_node) || warn_switch_enum)
3671       && type && TREE_CODE (type) == ENUMERAL_TYPE
3672       && TREE_CODE (SWITCH_COND (switch_stmt)) != INTEGER_CST)
3673     {
3674       tree chain;
3675
3676       /* The time complexity here is O(N*lg(N)) worst case, but for the
3677          common case of monotonically increasing enumerators, it is
3678          O(N), since the nature of the splay tree will keep the next
3679          element adjacent to the root at all times.  */
3680
3681       for (chain = TYPE_VALUES (type); chain; chain = TREE_CHAIN (chain))
3682         {
3683           splay_tree_node node
3684             = splay_tree_lookup (cases, (splay_tree_key) TREE_VALUE (chain));
3685
3686           if (node)
3687             {
3688               /* Mark the CASE_LOW part of the case entry as seen, so
3689                  that we save time later.  Choose TREE_ADDRESSABLE
3690                  randomly as a bit that won't have been set to-date.  */
3691               tree label = (tree) node->value;
3692               TREE_ADDRESSABLE (label) = 1;
3693             }
3694           else
3695             {
3696               /* Warn if there are enumerators that don't correspond to
3697                  case expressions.  */
3698               warning ("%Henumeration value %qE not handled in switch",
3699                        &switch_location, TREE_PURPOSE (chain));
3700             }
3701         }
3702
3703       /* Warn if there are case expressions that don't correspond to
3704          enumerators.  This can occur since C and C++ don't enforce
3705          type-checking of assignments to enumeration variables.
3706
3707          The time complexity here is O(N**2) worst case, since we've
3708          not sorted the enumeration values.  However, in the absence
3709          of case ranges this is O(N), since all single cases that
3710          corresponded to enumerations have been marked above.  */
3711
3712       splay_tree_foreach (cases, match_case_to_enum, type);
3713     }
3714 }
3715
3716 /* Finish an expression taking the address of LABEL (an
3717    IDENTIFIER_NODE).  Returns an expression for the address.  */
3718
3719 tree
3720 finish_label_address_expr (tree label)
3721 {
3722   tree result;
3723
3724   if (pedantic)
3725     pedwarn ("taking the address of a label is non-standard");
3726
3727   if (label == error_mark_node)
3728     return error_mark_node;
3729
3730   label = lookup_label (label);
3731   if (label == NULL_TREE)
3732     result = null_pointer_node;
3733   else
3734     {
3735       TREE_USED (label) = 1;
3736       result = build1 (ADDR_EXPR, ptr_type_node, label);
3737       /* The current function in not necessarily uninlinable.
3738          Computed gotos are incompatible with inlining, but the value
3739          here could be used only in a diagnostic, for example.  */
3740     }
3741
3742   return result;
3743 }
3744
3745 /* Hook used by expand_expr to expand language-specific tree codes.  */
3746 /* The only things that should go here are bits needed to expand
3747    constant initializers.  Everything else should be handled by the
3748    gimplification routines.  */
3749
3750 rtx
3751 c_expand_expr (tree exp, rtx target, enum machine_mode tmode,
3752                int modifier /* Actually enum_modifier.  */,
3753                rtx *alt_rtl)
3754 {
3755   switch (TREE_CODE (exp))
3756     {
3757     case COMPOUND_LITERAL_EXPR:
3758       {
3759         /* Initialize the anonymous variable declared in the compound
3760            literal, then return the variable.  */
3761         tree decl = COMPOUND_LITERAL_EXPR_DECL (exp);
3762         emit_local_var (decl);
3763         return expand_expr_real (decl, target, tmode, modifier, alt_rtl);
3764       }
3765
3766     default:
3767       gcc_unreachable ();
3768     }
3769 }
3770
3771 /* Hook used by staticp to handle language-specific tree codes.  */
3772
3773 tree
3774 c_staticp (tree exp)
3775 {
3776   return (TREE_CODE (exp) == COMPOUND_LITERAL_EXPR
3777           && TREE_STATIC (COMPOUND_LITERAL_EXPR_DECL (exp))
3778           ? exp : NULL);
3779 }
3780 \f
3781
3782 /* Given a boolean expression ARG, return a tree representing an increment
3783    or decrement (as indicated by CODE) of ARG.  The front end must check for
3784    invalid cases (e.g., decrement in C++).  */
3785 tree
3786 boolean_increment (enum tree_code code, tree arg)
3787 {
3788   tree val;
3789   tree true_res = boolean_true_node;
3790
3791   arg = stabilize_reference (arg);
3792   switch (code)
3793     {
3794     case PREINCREMENT_EXPR:
3795       val = build2 (MODIFY_EXPR, TREE_TYPE (arg), arg, true_res);
3796       break;
3797     case POSTINCREMENT_EXPR:
3798       val = build2 (MODIFY_EXPR, TREE_TYPE (arg), arg, true_res);
3799       arg = save_expr (arg);
3800       val = build2 (COMPOUND_EXPR, TREE_TYPE (arg), val, arg);
3801       val = build2 (COMPOUND_EXPR, TREE_TYPE (arg), arg, val);
3802       break;
3803     case PREDECREMENT_EXPR:
3804       val = build2 (MODIFY_EXPR, TREE_TYPE (arg), arg,
3805                     invert_truthvalue (arg));
3806       break;
3807     case POSTDECREMENT_EXPR:
3808       val = build2 (MODIFY_EXPR, TREE_TYPE (arg), arg,
3809                     invert_truthvalue (arg));
3810       arg = save_expr (arg);
3811       val = build2 (COMPOUND_EXPR, TREE_TYPE (arg), val, arg);
3812       val = build2 (COMPOUND_EXPR, TREE_TYPE (arg), arg, val);
3813       break;
3814     default:
3815       gcc_unreachable ();
3816     }
3817   TREE_SIDE_EFFECTS (val) = 1;
3818   return val;
3819 }
3820 \f
3821 /* Built-in macros for stddef.h, that require macros defined in this
3822    file.  */
3823 void
3824 c_stddef_cpp_builtins(void)
3825 {
3826   builtin_define_with_value ("__SIZE_TYPE__", SIZE_TYPE, 0);
3827   builtin_define_with_value ("__PTRDIFF_TYPE__", PTRDIFF_TYPE, 0);
3828   builtin_define_with_value ("__WCHAR_TYPE__", MODIFIED_WCHAR_TYPE, 0);
3829   builtin_define_with_value ("__WINT_TYPE__", WINT_TYPE, 0);
3830   builtin_define_with_value ("__INTMAX_TYPE__", INTMAX_TYPE, 0);
3831   builtin_define_with_value ("__UINTMAX_TYPE__", UINTMAX_TYPE, 0);
3832 }
3833
3834 static void
3835 c_init_attributes (void)
3836 {
3837   /* Fill in the built_in_attributes array.  */
3838 #define DEF_ATTR_NULL_TREE(ENUM)                                \
3839   built_in_attributes[(int) ENUM] = NULL_TREE;
3840 #define DEF_ATTR_INT(ENUM, VALUE)                               \
3841   built_in_attributes[(int) ENUM] = build_int_cst (NULL_TREE, VALUE);
3842 #define DEF_ATTR_IDENT(ENUM, STRING)                            \
3843   built_in_attributes[(int) ENUM] = get_identifier (STRING);
3844 #define DEF_ATTR_TREE_LIST(ENUM, PURPOSE, VALUE, CHAIN) \
3845   built_in_attributes[(int) ENUM]                       \
3846     = tree_cons (built_in_attributes[(int) PURPOSE],    \
3847                  built_in_attributes[(int) VALUE],      \
3848                  built_in_attributes[(int) CHAIN]);
3849 #include "builtin-attrs.def"
3850 #undef DEF_ATTR_NULL_TREE
3851 #undef DEF_ATTR_INT
3852 #undef DEF_ATTR_IDENT
3853 #undef DEF_ATTR_TREE_LIST
3854 }
3855
3856 /* Attribute handlers common to C front ends.  */
3857
3858 /* Handle a "packed" attribute; arguments as in
3859    struct attribute_spec.handler.  */
3860
3861 static tree
3862 handle_packed_attribute (tree *node, tree name, tree ARG_UNUSED (args),
3863                          int flags, bool *no_add_attrs)
3864 {
3865   if (TYPE_P (*node))
3866     {
3867       if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
3868         *node = build_variant_type_copy (*node);
3869       TYPE_PACKED (*node) = 1;
3870       if (TYPE_MAIN_VARIANT (*node) == *node)
3871         {
3872           /* If it is the main variant, then pack the other variants
3873              too. This happens in,
3874
3875              struct Foo {
3876                struct Foo const *ptr; // creates a variant w/o packed flag
3877                } __ attribute__((packed)); // packs it now.
3878           */
3879           tree probe;
3880
3881           for (probe = *node; probe; probe = TYPE_NEXT_VARIANT (probe))
3882             TYPE_PACKED (probe) = 1;
3883         }
3884
3885     }
3886   else if (TREE_CODE (*node) == FIELD_DECL)
3887     DECL_PACKED (*node) = 1;
3888   /* We can't set DECL_PACKED for a VAR_DECL, because the bit is
3889      used for DECL_REGISTER.  It wouldn't mean anything anyway.
3890      We can't set DECL_PACKED on the type of a TYPE_DECL, because
3891      that changes what the typedef is typing.  */
3892   else
3893     {
3894       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
3895       *no_add_attrs = true;
3896     }
3897
3898   return NULL_TREE;
3899 }
3900
3901 /* Handle a "nocommon" attribute; arguments as in
3902    struct attribute_spec.handler.  */
3903
3904 static tree
3905 handle_nocommon_attribute (tree *node, tree name,
3906                            tree ARG_UNUSED (args),
3907                            int ARG_UNUSED (flags), bool *no_add_attrs)
3908 {
3909   if (TREE_CODE (*node) == VAR_DECL)
3910     DECL_COMMON (*node) = 0;
3911   else
3912     {
3913       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
3914       *no_add_attrs = true;
3915     }
3916
3917   return NULL_TREE;
3918 }
3919
3920 /* Handle a "common" attribute; arguments as in
3921    struct attribute_spec.handler.  */
3922
3923 static tree
3924 handle_common_attribute (tree *node, tree name, tree ARG_UNUSED (args),
3925                          int ARG_UNUSED (flags), bool *no_add_attrs)
3926 {
3927   if (TREE_CODE (*node) == VAR_DECL)
3928     DECL_COMMON (*node) = 1;
3929   else
3930     {
3931       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
3932       *no_add_attrs = true;
3933     }
3934
3935   return NULL_TREE;
3936 }
3937
3938 /* Handle a "noreturn" attribute; arguments as in
3939    struct attribute_spec.handler.  */
3940
3941 static tree
3942 handle_noreturn_attribute (tree *node, tree name, tree ARG_UNUSED (args),
3943                            int ARG_UNUSED (flags), bool *no_add_attrs)
3944 {
3945   tree type = TREE_TYPE (*node);
3946
3947   /* See FIXME comment in c_common_attribute_table.  */
3948   if (TREE_CODE (*node) == FUNCTION_DECL)
3949     TREE_THIS_VOLATILE (*node) = 1;
3950   else if (TREE_CODE (type) == POINTER_TYPE
3951            && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE)
3952     TREE_TYPE (*node)
3953       = build_pointer_type
3954         (build_type_variant (TREE_TYPE (type),
3955                              TYPE_READONLY (TREE_TYPE (type)), 1));
3956   else
3957     {
3958       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
3959       *no_add_attrs = true;
3960     }
3961
3962   return NULL_TREE;
3963 }
3964
3965 /* Handle a "noinline" attribute; arguments as in
3966    struct attribute_spec.handler.  */
3967
3968 static tree
3969 handle_noinline_attribute (tree *node, tree name,
3970                            tree ARG_UNUSED (args),
3971                            int ARG_UNUSED (flags), bool *no_add_attrs)
3972 {
3973   if (TREE_CODE (*node) == FUNCTION_DECL)
3974     DECL_UNINLINABLE (*node) = 1;
3975   else
3976     {
3977       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
3978       *no_add_attrs = true;
3979     }
3980
3981   return NULL_TREE;
3982 }
3983
3984 /* Handle a "always_inline" attribute; arguments as in
3985    struct attribute_spec.handler.  */
3986
3987 static tree
3988 handle_always_inline_attribute (tree *node, tree name,
3989                                 tree ARG_UNUSED (args),
3990                                 int ARG_UNUSED (flags),
3991                                 bool *no_add_attrs)
3992 {
3993   if (TREE_CODE (*node) == FUNCTION_DECL)
3994     {
3995       /* Do nothing else, just set the attribute.  We'll get at
3996          it later with lookup_attribute.  */
3997     }
3998   else
3999     {
4000       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
4001       *no_add_attrs = true;
4002     }
4003
4004   return NULL_TREE;
4005 }
4006
4007 /* Handle a "used" attribute; arguments as in
4008    struct attribute_spec.handler.  */
4009
4010 static tree
4011 handle_used_attribute (tree *pnode, tree name, tree ARG_UNUSED (args),
4012                        int ARG_UNUSED (flags), bool *no_add_attrs)
4013 {
4014   tree node = *pnode;
4015
4016   if (TREE_CODE (node) == FUNCTION_DECL
4017       || (TREE_CODE (node) == VAR_DECL && TREE_STATIC (node)))
4018     {
4019       TREE_USED (node) = 1;
4020       DECL_PRESERVE_P (node) = 1;
4021     }
4022   else
4023     {
4024       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
4025       *no_add_attrs = true;
4026     }
4027
4028   return NULL_TREE;
4029 }
4030
4031 /* Handle a "unused" attribute; arguments as in
4032    struct attribute_spec.handler.  */
4033
4034 static tree
4035 handle_unused_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4036                          int flags, bool *no_add_attrs)
4037 {
4038   if (DECL_P (*node))
4039     {
4040       tree decl = *node;
4041
4042       if (TREE_CODE (decl) == PARM_DECL
4043           || TREE_CODE (decl) == VAR_DECL
4044           || TREE_CODE (decl) == FUNCTION_DECL
4045           || TREE_CODE (decl) == LABEL_DECL
4046           || TREE_CODE (decl) == TYPE_DECL)
4047         TREE_USED (decl) = 1;
4048       else
4049         {
4050           warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
4051           *no_add_attrs = true;
4052         }
4053     }
4054   else
4055     {
4056       if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
4057         *node = build_variant_type_copy (*node);
4058       TREE_USED (*node) = 1;
4059     }
4060
4061   return NULL_TREE;
4062 }
4063
4064 /* Handle a "const" attribute; arguments as in
4065    struct attribute_spec.handler.  */
4066
4067 static tree
4068 handle_const_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4069                         int ARG_UNUSED (flags), bool *no_add_attrs)
4070 {
4071   tree type = TREE_TYPE (*node);
4072
4073   /* See FIXME comment on noreturn in c_common_attribute_table.  */
4074   if (TREE_CODE (*node) == FUNCTION_DECL)
4075     TREE_READONLY (*node) = 1;
4076   else if (TREE_CODE (type) == POINTER_TYPE
4077            && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE)
4078     TREE_TYPE (*node)
4079       = build_pointer_type
4080         (build_type_variant (TREE_TYPE (type), 1,
4081                              TREE_THIS_VOLATILE (TREE_TYPE (type))));
4082   else
4083     {
4084       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
4085       *no_add_attrs = true;
4086     }
4087
4088   return NULL_TREE;
4089 }
4090
4091 /* Handle a "transparent_union" attribute; arguments as in
4092    struct attribute_spec.handler.  */
4093
4094 static tree
4095 handle_transparent_union_attribute (tree *node, tree name,
4096                                     tree ARG_UNUSED (args), int flags,
4097                                     bool *no_add_attrs)
4098 {
4099   tree decl = NULL_TREE;
4100   tree *type = NULL;
4101   int is_type = 0;
4102
4103   if (DECL_P (*node))
4104     {
4105       decl = *node;
4106       type = &TREE_TYPE (decl);
4107       is_type = TREE_CODE (*node) == TYPE_DECL;
4108     }
4109   else if (TYPE_P (*node))
4110     type = node, is_type = 1;
4111
4112   if (is_type
4113       && TREE_CODE (*type) == UNION_TYPE
4114       && (decl == 0
4115           || (TYPE_FIELDS (*type) != 0
4116               && TYPE_MODE (*type) == DECL_MODE (TYPE_FIELDS (*type)))))
4117     {
4118       if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
4119         *type = build_variant_type_copy (*type);
4120       TYPE_TRANSPARENT_UNION (*type) = 1;
4121     }
4122   else if (decl != 0 && TREE_CODE (decl) == PARM_DECL
4123            && TREE_CODE (*type) == UNION_TYPE
4124            && TYPE_MODE (*type) == DECL_MODE (TYPE_FIELDS (*type)))
4125     DECL_TRANSPARENT_UNION (decl) = 1;
4126   else
4127     {
4128       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
4129       *no_add_attrs = true;
4130     }
4131
4132   return NULL_TREE;
4133 }
4134
4135 /* Handle a "constructor" attribute; arguments as in
4136    struct attribute_spec.handler.  */
4137
4138 static tree
4139 handle_constructor_attribute (tree *node, tree name,
4140                               tree ARG_UNUSED (args),
4141                               int ARG_UNUSED (flags),
4142                               bool *no_add_attrs)
4143 {
4144   tree decl = *node;
4145   tree type = TREE_TYPE (decl);
4146
4147   if (TREE_CODE (decl) == FUNCTION_DECL
4148       && TREE_CODE (type) == FUNCTION_TYPE
4149       && decl_function_context (decl) == 0)
4150     {
4151       DECL_STATIC_CONSTRUCTOR (decl) = 1;
4152       TREE_USED (decl) = 1;
4153     }
4154   else
4155     {
4156       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
4157       *no_add_attrs = true;
4158     }
4159
4160   return NULL_TREE;
4161 }
4162
4163 /* Handle a "destructor" attribute; arguments as in
4164    struct attribute_spec.handler.  */
4165
4166 static tree
4167 handle_destructor_attribute (tree *node, tree name,
4168                              tree ARG_UNUSED (args),
4169                              int ARG_UNUSED (flags),
4170                              bool *no_add_attrs)
4171 {
4172   tree decl = *node;
4173   tree type = TREE_TYPE (decl);
4174
4175   if (TREE_CODE (decl) == FUNCTION_DECL
4176       && TREE_CODE (type) == FUNCTION_TYPE
4177       && decl_function_context (decl) == 0)
4178     {
4179       DECL_STATIC_DESTRUCTOR (decl) = 1;
4180       TREE_USED (decl) = 1;
4181     }
4182   else
4183     {
4184       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
4185       *no_add_attrs = true;
4186     }
4187
4188   return NULL_TREE;
4189 }
4190
4191 /* Handle a "mode" attribute; arguments as in
4192    struct attribute_spec.handler.  */
4193
4194 static tree
4195 handle_mode_attribute (tree *node, tree name, tree args,
4196                        int ARG_UNUSED (flags), bool *no_add_attrs)
4197 {
4198   tree type = *node;
4199
4200   *no_add_attrs = true;
4201
4202   if (TREE_CODE (TREE_VALUE (args)) != IDENTIFIER_NODE)
4203     warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
4204   else
4205     {
4206       int j;
4207       const char *p = IDENTIFIER_POINTER (TREE_VALUE (args));
4208       int len = strlen (p);
4209       enum machine_mode mode = VOIDmode;
4210       tree typefm;
4211       bool valid_mode;
4212
4213       if (len > 4 && p[0] == '_' && p[1] == '_'
4214           && p[len - 1] == '_' && p[len - 2] == '_')
4215         {
4216           char *newp = (char *) alloca (len - 1);
4217
4218           strcpy (newp, &p[2]);
4219           newp[len - 4] = '\0';
4220           p = newp;
4221         }
4222
4223       /* Change this type to have a type with the specified mode.
4224          First check for the special modes.  */
4225       if (!strcmp (p, "byte"))
4226         mode = byte_mode;
4227       else if (!strcmp (p, "word"))
4228         mode = word_mode;
4229       else if (!strcmp (p, "pointer"))
4230         mode = ptr_mode;
4231       else
4232         for (j = 0; j < NUM_MACHINE_MODES; j++)
4233           if (!strcmp (p, GET_MODE_NAME (j)))
4234             {
4235               mode = (enum machine_mode) j;
4236               break;
4237             }
4238
4239       if (mode == VOIDmode)
4240         {
4241           error ("unknown machine mode %qs", p);
4242           return NULL_TREE;
4243         }
4244
4245       valid_mode = false;
4246       switch (GET_MODE_CLASS (mode))
4247         {
4248         case MODE_INT:
4249         case MODE_PARTIAL_INT:
4250         case MODE_FLOAT:
4251           valid_mode = targetm.scalar_mode_supported_p (mode);
4252           break;
4253
4254         case MODE_COMPLEX_INT:
4255         case MODE_COMPLEX_FLOAT:
4256           valid_mode = targetm.scalar_mode_supported_p (GET_MODE_INNER (mode));
4257           break;
4258
4259         case MODE_VECTOR_INT:
4260         case MODE_VECTOR_FLOAT:
4261           warning ("specifying vector types with __attribute__ ((mode)) "
4262                    "is deprecated");
4263           warning ("use __attribute__ ((vector_size)) instead");
4264           valid_mode = vector_mode_valid_p (mode);
4265           break;
4266
4267         default:
4268           break;
4269         }
4270       if (!valid_mode)
4271         {
4272           error ("unable to emulate %qs", p);
4273           return NULL_TREE;
4274         }
4275
4276       if (POINTER_TYPE_P (type))
4277         {
4278           tree (*fn)(tree, enum machine_mode, bool);
4279
4280           if (!targetm.valid_pointer_mode (mode))
4281             {
4282               error ("invalid pointer mode %qs", p);
4283               return NULL_TREE;
4284             }
4285
4286           if (TREE_CODE (type) == POINTER_TYPE)
4287             fn = build_pointer_type_for_mode;
4288           else
4289             fn = build_reference_type_for_mode;
4290           typefm = fn (TREE_TYPE (type), mode, false);
4291         }
4292       else
4293         typefm = lang_hooks.types.type_for_mode (mode, TYPE_UNSIGNED (type));
4294
4295       if (typefm == NULL_TREE)
4296         {
4297           error ("no data type for mode %qs", p);
4298           return NULL_TREE;
4299         }
4300       else if (TREE_CODE (type) == ENUMERAL_TYPE)
4301         {
4302           /* For enumeral types, copy the precision from the integer
4303              type returned above.  If not an INTEGER_TYPE, we can't use
4304              this mode for this type.  */
4305           if (TREE_CODE (typefm) != INTEGER_TYPE)
4306             {
4307               error ("cannot use mode %qs for enumeral types", p);
4308               return NULL_TREE;
4309             }
4310
4311           if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
4312             type = build_variant_type_copy (type);
4313           TYPE_PRECISION (type) = TYPE_PRECISION (typefm);
4314           typefm = type;
4315         }
4316       else if (VECTOR_MODE_P (mode)
4317                ? TREE_CODE (type) != TREE_CODE (TREE_TYPE (typefm))
4318                : TREE_CODE (type) != TREE_CODE (typefm))
4319         {
4320           error ("mode %qs applied to inappropriate type", p);
4321           return NULL_TREE;
4322         }
4323
4324       *node = typefm;
4325
4326       /* No need to layout the type here.  The caller should do this.  */
4327     }
4328
4329   return NULL_TREE;
4330 }
4331
4332 /* Handle a "section" attribute; arguments as in
4333    struct attribute_spec.handler.  */
4334
4335 static tree
4336 handle_section_attribute (tree *node, tree ARG_UNUSED (name), tree args,
4337                           int ARG_UNUSED (flags), bool *no_add_attrs)
4338 {
4339   tree decl = *node;
4340
4341   if (targetm.have_named_sections)
4342     {
4343       user_defined_section_attribute = true;
4344
4345       if ((TREE_CODE (decl) == FUNCTION_DECL
4346            || TREE_CODE (decl) == VAR_DECL)
4347           && TREE_CODE (TREE_VALUE (args)) == STRING_CST)
4348         {
4349           if (TREE_CODE (decl) == VAR_DECL
4350               && current_function_decl != NULL_TREE
4351               && !TREE_STATIC (decl))
4352             {
4353               error ("%Jsection attribute cannot be specified for "
4354                      "local variables", decl);
4355               *no_add_attrs = true;
4356             }
4357
4358           /* The decl may have already been given a section attribute
4359              from a previous declaration.  Ensure they match.  */
4360           else if (DECL_SECTION_NAME (decl) != NULL_TREE
4361                    && strcmp (TREE_STRING_POINTER (DECL_SECTION_NAME (decl)),
4362                               TREE_STRING_POINTER (TREE_VALUE (args))) != 0)
4363             {
4364               error ("%Jsection of %qD conflicts with previous declaration",
4365                      *node, *node);
4366               *no_add_attrs = true;
4367             }
4368           else
4369             DECL_SECTION_NAME (decl) = TREE_VALUE (args);
4370         }
4371       else
4372         {
4373           error ("%Jsection attribute not allowed for %qD", *node, *node);
4374           *no_add_attrs = true;
4375         }
4376     }
4377   else
4378     {
4379       error ("%Jsection attributes are not supported for this target", *node);
4380       *no_add_attrs = true;
4381     }
4382
4383   return NULL_TREE;
4384 }
4385
4386 /* Handle a "aligned" attribute; arguments as in
4387    struct attribute_spec.handler.  */
4388
4389 static tree
4390 handle_aligned_attribute (tree *node, tree ARG_UNUSED (name), tree args,
4391                           int flags, bool *no_add_attrs)
4392 {
4393   tree decl = NULL_TREE;
4394   tree *type = NULL;
4395   int is_type = 0;
4396   tree align_expr = (args ? TREE_VALUE (args)
4397                      : size_int (BIGGEST_ALIGNMENT / BITS_PER_UNIT));
4398   int i;
4399
4400   if (DECL_P (*node))
4401     {
4402       decl = *node;
4403       type = &TREE_TYPE (decl);
4404       is_type = TREE_CODE (*node) == TYPE_DECL;
4405     }
4406   else if (TYPE_P (*node))
4407     type = node, is_type = 1;
4408
4409   /* Strip any NOPs of any kind.  */
4410   while (TREE_CODE (align_expr) == NOP_EXPR
4411          || TREE_CODE (align_expr) == CONVERT_EXPR
4412          || TREE_CODE (align_expr) == NON_LVALUE_EXPR)
4413     align_expr = TREE_OPERAND (align_expr, 0);
4414
4415   if (TREE_CODE (align_expr) != INTEGER_CST)
4416     {
4417       error ("requested alignment is not a constant");
4418       *no_add_attrs = true;
4419     }
4420   else if ((i = tree_log2 (align_expr)) == -1)
4421     {
4422       error ("requested alignment is not a power of 2");
4423       *no_add_attrs = true;
4424     }
4425   else if (i > HOST_BITS_PER_INT - 2)
4426     {
4427       error ("requested alignment is too large");
4428       *no_add_attrs = true;
4429     }
4430   else if (is_type)
4431     {
4432       /* If we have a TYPE_DECL, then copy the type, so that we
4433          don't accidentally modify a builtin type.  See pushdecl.  */
4434       if (decl && TREE_TYPE (decl) != error_mark_node
4435           && DECL_ORIGINAL_TYPE (decl) == NULL_TREE)
4436         {
4437           tree tt = TREE_TYPE (decl);
4438           *type = build_variant_type_copy (*type);
4439           DECL_ORIGINAL_TYPE (decl) = tt;
4440           TYPE_NAME (*type) = decl;
4441           TREE_USED (*type) = TREE_USED (decl);
4442           TREE_TYPE (decl) = *type;
4443         }
4444       else if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
4445         *type = build_variant_type_copy (*type);
4446
4447       TYPE_ALIGN (*type) = (1 << i) * BITS_PER_UNIT;
4448       TYPE_USER_ALIGN (*type) = 1;
4449     }
4450   else if (TREE_CODE (decl) != VAR_DECL
4451            && TREE_CODE (decl) != FIELD_DECL)
4452     {
4453       error ("%Jalignment may not be specified for %qD", decl, decl);
4454       *no_add_attrs = true;
4455     }
4456   else
4457     {
4458       DECL_ALIGN (decl) = (1 << i) * BITS_PER_UNIT;
4459       DECL_USER_ALIGN (decl) = 1;
4460     }
4461
4462   return NULL_TREE;
4463 }
4464
4465 /* Handle a "weak" attribute; arguments as in
4466    struct attribute_spec.handler.  */
4467
4468 static tree
4469 handle_weak_attribute (tree *node, tree ARG_UNUSED (name),
4470                        tree ARG_UNUSED (args),
4471                        int ARG_UNUSED (flags),
4472                        bool * ARG_UNUSED (no_add_attrs))
4473 {
4474   declare_weak (*node);
4475
4476   return NULL_TREE;
4477 }
4478
4479 /* Handle an "alias" attribute; arguments as in
4480    struct attribute_spec.handler.  */
4481
4482 static tree
4483 handle_alias_attribute (tree *node, tree name, tree args,
4484                         int ARG_UNUSED (flags), bool *no_add_attrs)
4485 {
4486   tree decl = *node;
4487
4488   if ((TREE_CODE (decl) == FUNCTION_DECL && DECL_INITIAL (decl))
4489       || (TREE_CODE (decl) != FUNCTION_DECL && !DECL_EXTERNAL (decl)))
4490     {
4491       error ("%J%qD defined both normally and as an alias", decl, decl);
4492       *no_add_attrs = true;
4493     }
4494
4495   /* Note that the very first time we process a nested declaration,
4496      decl_function_context will not be set.  Indeed, *would* never
4497      be set except for the DECL_INITIAL/DECL_EXTERNAL frobbery that
4498      we do below.  After such frobbery, pushdecl would set the context.
4499      In any case, this is never what we want.  */
4500   else if (decl_function_context (decl) == 0 && current_function_decl == NULL)
4501     {
4502       tree id;
4503
4504       id = TREE_VALUE (args);
4505       if (TREE_CODE (id) != STRING_CST)
4506         {
4507           error ("alias argument not a string");
4508           *no_add_attrs = true;
4509           return NULL_TREE;
4510         }
4511       id = get_identifier (TREE_STRING_POINTER (id));
4512       /* This counts as a use of the object pointed to.  */
4513       TREE_USED (id) = 1;
4514
4515       if (TREE_CODE (decl) == FUNCTION_DECL)
4516         DECL_INITIAL (decl) = error_mark_node;
4517       else
4518         {
4519           DECL_EXTERNAL (decl) = 0;
4520           TREE_STATIC (decl) = 1;
4521         }
4522     }
4523   else
4524     {
4525       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
4526       *no_add_attrs = true;
4527     }
4528
4529   return NULL_TREE;
4530 }
4531
4532 /* Handle an "visibility" attribute; arguments as in
4533    struct attribute_spec.handler.  */
4534
4535 static tree
4536 handle_visibility_attribute (tree *node, tree name, tree args,
4537                              int ARG_UNUSED (flags),
4538                              bool *no_add_attrs)
4539 {
4540   tree decl = *node;
4541   tree id = TREE_VALUE (args);
4542
4543   *no_add_attrs = true;
4544
4545   if (TYPE_P (*node))
4546     {
4547       if (TREE_CODE (*node) != RECORD_TYPE && TREE_CODE (*node) != UNION_TYPE)
4548        {
4549          warning ("%qs attribute ignored on non-class types",
4550                   IDENTIFIER_POINTER (name));
4551          return NULL_TREE;
4552        }
4553     }
4554   else if (decl_function_context (decl) != 0 || !TREE_PUBLIC (decl))
4555     {
4556       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
4557       return NULL_TREE;
4558     }
4559
4560   if (TREE_CODE (id) != STRING_CST)
4561     {
4562       error ("visibility argument not a string");
4563       return NULL_TREE;
4564     }
4565
4566   /*  If this is a type, set the visibility on the type decl.  */
4567   if (TYPE_P (decl))
4568     {
4569       decl = TYPE_NAME (decl);
4570       if (!decl)
4571         return NULL_TREE;
4572       if (TREE_CODE (decl) == IDENTIFIER_NODE)
4573         {
4574            warning ("%qE attribute ignored on types",
4575                     name);
4576            return NULL_TREE;
4577         }
4578     }
4579
4580   if (strcmp (TREE_STRING_POINTER (id), "default") == 0)
4581     DECL_VISIBILITY (decl) = VISIBILITY_DEFAULT;
4582   else if (strcmp (TREE_STRING_POINTER (id), "internal") == 0)
4583     DECL_VISIBILITY (decl) = VISIBILITY_INTERNAL;
4584   else if (strcmp (TREE_STRING_POINTER (id), "hidden") == 0)
4585     DECL_VISIBILITY (decl) = VISIBILITY_HIDDEN;
4586   else if (strcmp (TREE_STRING_POINTER (id), "protected") == 0)
4587     DECL_VISIBILITY (decl) = VISIBILITY_PROTECTED;
4588   else
4589     error ("visibility argument must be one of \"default\", \"hidden\", \"protected\" or \"internal\"");
4590   DECL_VISIBILITY_SPECIFIED (decl) = 1;
4591
4592   /* For decls only, go ahead and attach the attribute to the node as well.
4593      This is needed so we can determine whether we have VISIBILITY_DEFAULT
4594      because the visibility was not specified, or because it was explicitly
4595      overridden from the class visibility.  */
4596   if (DECL_P (*node))
4597     *no_add_attrs = false;
4598
4599   return NULL_TREE;
4600 }
4601
4602 /* Determine the ELF symbol visibility for DECL, which is either a
4603    variable or a function.  It is an error to use this function if a
4604    definition of DECL is not available in this translation unit.
4605    Returns true if the final visibility has been determined by this
4606    function; false if the caller is free to make additional
4607    modifications.  */
4608
4609 bool
4610 c_determine_visibility (tree decl)
4611 {
4612   gcc_assert (TREE_CODE (decl) == VAR_DECL
4613               || TREE_CODE (decl) == FUNCTION_DECL);
4614
4615   /* If the user explicitly specified the visibility with an
4616      attribute, honor that.  DECL_VISIBILITY will have been set during
4617      the processing of the attribute.  We check for an explicit
4618      attribute, rather than just checking DECL_VISIBILITY_SPECIFIED,
4619      to distinguish the use of an attribute from the use of a "#pragma
4620      GCC visibility push(...)"; in the latter case we still want other
4621      considerations to be able to overrule the #pragma.  */
4622   if (lookup_attribute ("visibility", DECL_ATTRIBUTES (decl)))
4623     return true;
4624
4625   /* Anything that is exported must have default visibility.  */
4626   if (TARGET_DLLIMPORT_DECL_ATTRIBUTES
4627       && lookup_attribute ("dllexport", DECL_ATTRIBUTES (decl)))
4628     {
4629       DECL_VISIBILITY (decl) = VISIBILITY_DEFAULT;
4630       DECL_VISIBILITY_SPECIFIED (decl) = 1;
4631       return true;
4632     }
4633
4634   return false;
4635 }
4636
4637 /* Handle an "tls_model" attribute; arguments as in
4638    struct attribute_spec.handler.  */
4639
4640 static tree
4641 handle_tls_model_attribute (tree *node, tree name, tree args,
4642                             int ARG_UNUSED (flags), bool *no_add_attrs)
4643 {
4644   tree decl = *node;
4645
4646   if (!DECL_THREAD_LOCAL (decl))
4647     {
4648       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
4649       *no_add_attrs = true;
4650     }
4651   else
4652     {
4653       tree id;
4654
4655       id = TREE_VALUE (args);
4656       if (TREE_CODE (id) != STRING_CST)
4657         {
4658           error ("tls_model argument not a string");
4659           *no_add_attrs = true;
4660           return NULL_TREE;
4661         }
4662       if (strcmp (TREE_STRING_POINTER (id), "local-exec")
4663           && strcmp (TREE_STRING_POINTER (id), "initial-exec")
4664           && strcmp (TREE_STRING_POINTER (id), "local-dynamic")
4665           && strcmp (TREE_STRING_POINTER (id), "global-dynamic"))
4666         {
4667           error ("tls_model argument must be one of \"local-exec\", \"initial-exec\", \"local-dynamic\" or \"global-dynamic\"");
4668           *no_add_attrs = true;
4669           return NULL_TREE;
4670         }
4671     }
4672
4673   return NULL_TREE;
4674 }
4675
4676 /* Handle a "no_instrument_function" attribute; arguments as in
4677    struct attribute_spec.handler.  */
4678
4679 static tree
4680 handle_no_instrument_function_attribute (tree *node, tree name,
4681                                          tree ARG_UNUSED (args),
4682                                          int ARG_UNUSED (flags),
4683                                          bool *no_add_attrs)
4684 {
4685   tree decl = *node;
4686
4687   if (TREE_CODE (decl) != FUNCTION_DECL)
4688     {
4689       error ("%J%qE attribute applies only to functions", decl, name);
4690       *no_add_attrs = true;
4691     }
4692   else if (DECL_INITIAL (decl))
4693     {
4694       error ("%Jcan%'t set %qE attribute after definition", decl, name);
4695       *no_add_attrs = true;
4696     }
4697   else
4698     DECL_NO_INSTRUMENT_FUNCTION_ENTRY_EXIT (decl) = 1;
4699
4700   return NULL_TREE;
4701 }
4702
4703 /* Handle a "malloc" attribute; arguments as in
4704    struct attribute_spec.handler.  */
4705
4706 static tree
4707 handle_malloc_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4708                          int ARG_UNUSED (flags), bool *no_add_attrs)
4709 {
4710   if (TREE_CODE (*node) == FUNCTION_DECL)
4711     DECL_IS_MALLOC (*node) = 1;
4712   /* ??? TODO: Support types.  */
4713   else
4714     {
4715       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
4716       *no_add_attrs = true;
4717     }
4718
4719   return NULL_TREE;
4720 }
4721
4722 /* Handle a "no_limit_stack" attribute; arguments as in
4723    struct attribute_spec.handler.  */
4724
4725 static tree
4726 handle_no_limit_stack_attribute (tree *node, tree name,
4727                                  tree ARG_UNUSED (args),
4728                                  int ARG_UNUSED (flags),
4729                                  bool *no_add_attrs)
4730 {
4731   tree decl = *node;
4732
4733   if (TREE_CODE (decl) != FUNCTION_DECL)
4734     {
4735       error ("%J%qE attribute applies only to functions", decl, name);
4736       *no_add_attrs = true;
4737     }
4738   else if (DECL_INITIAL (decl))
4739     {
4740       error ("%Jcan%'t set %qE attribute after definition", decl, name);
4741       *no_add_attrs = true;
4742     }
4743   else
4744     DECL_NO_LIMIT_STACK (decl) = 1;
4745
4746   return NULL_TREE;
4747 }
4748
4749 /* Handle a "pure" attribute; arguments as in
4750    struct attribute_spec.handler.  */
4751
4752 static tree
4753 handle_pure_attribute (tree *node, tree name, tree ARG_UNUSED (args),
4754                        int ARG_UNUSED (flags), bool *no_add_attrs)
4755 {
4756   if (TREE_CODE (*node) == FUNCTION_DECL)
4757     DECL_IS_PURE (*node) = 1;
4758   /* ??? TODO: Support types.  */
4759   else
4760     {
4761       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
4762       *no_add_attrs = true;
4763     }
4764
4765   return NULL_TREE;
4766 }
4767
4768 /* Handle a "deprecated" attribute; arguments as in
4769    struct attribute_spec.handler.  */
4770
4771 static tree
4772 handle_deprecated_attribute (tree *node, tree name,
4773                              tree ARG_UNUSED (args), int flags,
4774                              bool *no_add_attrs)
4775 {
4776   tree type = NULL_TREE;
4777   int warn = 0;
4778   const char *what = NULL;
4779
4780   if (DECL_P (*node))
4781     {
4782       tree decl = *node;
4783       type = TREE_TYPE (decl);
4784
4785       if (TREE_CODE (decl) == TYPE_DECL
4786           || TREE_CODE (decl) == PARM_DECL
4787           || TREE_CODE (decl) == VAR_DECL
4788           || TREE_CODE (decl) == FUNCTION_DECL
4789           || TREE_CODE (decl) == FIELD_DECL)
4790         TREE_DEPRECATED (decl) = 1;
4791       else
4792         warn = 1;
4793     }
4794   else if (TYPE_P (*node))
4795     {
4796       if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
4797         *node = build_variant_type_copy (*node);
4798       TREE_DEPRECATED (*node) = 1;
4799       type = *node;
4800     }
4801   else
4802     warn = 1;
4803
4804   if (warn)
4805     {
4806       *no_add_attrs = true;
4807       if (type && TYPE_NAME (type))
4808         {
4809           if (TREE_CODE (TYPE_NAME (type)) == IDENTIFIER_NODE)
4810             what = IDENTIFIER_POINTER (TYPE_NAME (*node));
4811           else if (TREE_CODE (TYPE_NAME (type)) == TYPE_DECL
4812                    && DECL_NAME (TYPE_NAME (type)))
4813             what = IDENTIFIER_POINTER (DECL_NAME (TYPE_NAME (type)));
4814         }
4815       if (what)
4816         warning ("%qs attribute ignored for %qs",
4817                   IDENTIFIER_POINTER (name), what);
4818       else
4819         warning ("%qs attribute ignored",
4820                       IDENTIFIER_POINTER (name));
4821     }
4822
4823   return NULL_TREE;
4824 }
4825
4826 /* Handle a "vector_size" attribute; arguments as in
4827    struct attribute_spec.handler.  */
4828
4829 static tree
4830 handle_vector_size_attribute (tree *node, tree name, tree args,
4831                               int ARG_UNUSED (flags),
4832                               bool *no_add_attrs)
4833 {
4834   unsigned HOST_WIDE_INT vecsize, nunits;
4835   enum machine_mode orig_mode;
4836   tree type = *node, new_type, size;
4837
4838   *no_add_attrs = true;
4839
4840   /* Stripping NON_LVALUE_EXPR allows declarations such as
4841      typedef short v4si __attribute__((vector_size (4 * sizeof(short)))).  */
4842   size = TREE_VALUE (args);
4843   if (TREE_CODE (size) == NON_LVALUE_EXPR)
4844     size = TREE_OPERAND (size, 0);
4845
4846   if (!host_integerp (size, 1))
4847     {
4848       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
4849       return NULL_TREE;
4850     }
4851
4852   /* Get the vector size (in bytes).  */
4853   vecsize = tree_low_cst (size, 1);
4854
4855   /* We need to provide for vector pointers, vector arrays, and
4856      functions returning vectors.  For example:
4857
4858        __attribute__((vector_size(16))) short *foo;
4859
4860      In this case, the mode is SI, but the type being modified is
4861      HI, so we need to look further.  */
4862
4863   while (POINTER_TYPE_P (type)
4864          || TREE_CODE (type) == FUNCTION_TYPE
4865          || TREE_CODE (type) == METHOD_TYPE
4866          || TREE_CODE (type) == ARRAY_TYPE)
4867     type = TREE_TYPE (type);
4868
4869   /* Get the mode of the type being modified.  */
4870   orig_mode = TYPE_MODE (type);
4871
4872   if (TREE_CODE (type) == RECORD_TYPE
4873       || (GET_MODE_CLASS (orig_mode) != MODE_FLOAT
4874           && GET_MODE_CLASS (orig_mode) != MODE_INT)
4875       || !host_integerp (TYPE_SIZE_UNIT (type), 1))
4876     {
4877       error ("invalid vector type for attribute %qs",
4878              IDENTIFIER_POINTER (name));
4879       return NULL_TREE;
4880     }
4881
4882   /* Calculate how many units fit in the vector.  */
4883   nunits = vecsize / tree_low_cst (TYPE_SIZE_UNIT (type), 1);
4884   if (nunits & (nunits - 1))
4885     {
4886       error ("number of components of the vector not a power of two");
4887       return NULL_TREE;
4888     }
4889
4890   new_type = build_vector_type (type, nunits);
4891
4892   /* Build back pointers if needed.  */
4893   *node = reconstruct_complex_type (*node, new_type);
4894
4895   return NULL_TREE;
4896 }
4897
4898 /* Handle the "nonnull" attribute.  */
4899 static tree
4900 handle_nonnull_attribute (tree *node, tree ARG_UNUSED (name),
4901                           tree args, int ARG_UNUSED (flags),
4902                           bool *no_add_attrs)
4903 {
4904   tree type = *node;
4905   unsigned HOST_WIDE_INT attr_arg_num;
4906
4907   /* If no arguments are specified, all pointer arguments should be
4908      non-null.  Verify a full prototype is given so that the arguments
4909      will have the correct types when we actually check them later.  */
4910   if (!args)
4911     {
4912       if (!TYPE_ARG_TYPES (type))
4913         {
4914           error ("nonnull attribute without arguments on a non-prototype");
4915           *no_add_attrs = true;
4916         }
4917       return NULL_TREE;
4918     }
4919
4920   /* Argument list specified.  Verify that each argument number references
4921      a pointer argument.  */
4922   for (attr_arg_num = 1; args; args = TREE_CHAIN (args))
4923     {
4924       tree argument;
4925       unsigned HOST_WIDE_INT arg_num = 0, ck_num;
4926
4927       if (!get_nonnull_operand (TREE_VALUE (args), &arg_num))
4928         {
4929           error ("nonnull argument has invalid operand number (argument %lu)",
4930                  (unsigned long) attr_arg_num);
4931           *no_add_attrs = true;
4932           return NULL_TREE;
4933         }
4934
4935       argument = TYPE_ARG_TYPES (type);
4936       if (argument)
4937         {
4938           for (ck_num = 1; ; ck_num++)
4939             {
4940               if (!argument || ck_num == arg_num)
4941                 break;
4942               argument = TREE_CHAIN (argument);
4943             }
4944
4945           if (!argument
4946               || TREE_CODE (TREE_VALUE (argument)) == VOID_TYPE)
4947             {
4948               error ("nonnull argument with out-of-range operand number (argument %lu, operand %lu)",
4949                      (unsigned long) attr_arg_num, (unsigned long) arg_num);
4950               *no_add_attrs = true;
4951               return NULL_TREE;
4952             }
4953
4954           if (TREE_CODE (TREE_VALUE (argument)) != POINTER_TYPE)
4955             {
4956               error ("nonnull argument references non-pointer operand (argument %lu, operand %lu)",
4957                    (unsigned long) attr_arg_num, (unsigned long) arg_num);
4958               *no_add_attrs = true;
4959               return NULL_TREE;
4960             }
4961         }
4962     }
4963
4964   return NULL_TREE;
4965 }
4966
4967 /* Check the argument list of a function call for null in argument slots
4968    that are marked as requiring a non-null pointer argument.  */
4969
4970 static void
4971 check_function_nonnull (tree attrs, tree params)
4972 {
4973   tree a, args, param;
4974   int param_num;
4975
4976   for (a = attrs; a; a = TREE_CHAIN (a))
4977     {
4978       if (is_attribute_p ("nonnull", TREE_PURPOSE (a)))
4979         {
4980           args = TREE_VALUE (a);
4981
4982           /* Walk the argument list.  If we encounter an argument number we
4983              should check for non-null, do it.  If the attribute has no args,
4984              then every pointer argument is checked (in which case the check
4985              for pointer type is done in check_nonnull_arg).  */
4986           for (param = params, param_num = 1; ;
4987                param_num++, param = TREE_CHAIN (param))
4988             {
4989               if (!param)
4990         break;
4991               if (!args || nonnull_check_p (args, param_num))
4992         check_function_arguments_recurse (check_nonnull_arg, NULL,
4993                                           TREE_VALUE (param),
4994                                           param_num);
4995             }
4996         }
4997     }
4998 }
4999
5000 /* Check that the Nth argument of a function call (counting backwards
5001    from the end) is a (pointer)0.  */
5002
5003 static void
5004 check_function_sentinel (tree attrs, tree params)
5005 {
5006   tree attr = lookup_attribute ("sentinel", attrs);
5007
5008   if (attr)
5009     {
5010       if (!params)
5011         warning ("missing sentinel in function call");
5012       else
5013         {
5014           tree sentinel, end;
5015           unsigned pos = 0;
5016
5017           if (TREE_VALUE (attr))
5018             {
5019               tree p = TREE_VALUE (TREE_VALUE (attr));
5020               STRIP_NOPS (p);
5021               pos = TREE_INT_CST_LOW (p);
5022             }
5023
5024           sentinel = end = params;
5025
5026           /* Advance `end' ahead of `sentinel' by `pos' positions.  */
5027           while (pos > 0 && TREE_CHAIN (end))
5028             {
5029               pos--;
5030               end = TREE_CHAIN (end);
5031             }
5032           if (pos > 0)
5033             {
5034               warning ("not enough arguments to fit a sentinel");
5035               return;
5036             }
5037
5038           /* Now advance both until we find the last parameter.  */
5039           while (TREE_CHAIN (end))
5040             {
5041               end = TREE_CHAIN (end);
5042               sentinel = TREE_CHAIN (sentinel);
5043             }
5044
5045           /* Validate the sentinel.  */
5046           if (!POINTER_TYPE_P (TREE_TYPE (TREE_VALUE (sentinel)))
5047               || !integer_zerop (TREE_VALUE (sentinel)))
5048             warning ("missing sentinel in function call");
5049         }
5050     }
5051 }
5052
5053 /* Helper for check_function_nonnull; given a list of operands which
5054    must be non-null in ARGS, determine if operand PARAM_NUM should be
5055    checked.  */
5056
5057 static bool
5058 nonnull_check_p (tree args, unsigned HOST_WIDE_INT param_num)
5059 {
5060   unsigned HOST_WIDE_INT arg_num = 0;
5061
5062   for (; args; args = TREE_CHAIN (args))
5063     {
5064       bool found = get_nonnull_operand (TREE_VALUE (args), &arg_num);
5065
5066       gcc_assert (found);
5067
5068       if (arg_num == param_num)
5069         return true;
5070     }
5071   return false;
5072 }
5073
5074 /* Check that the function argument PARAM (which is operand number
5075    PARAM_NUM) is non-null.  This is called by check_function_nonnull
5076    via check_function_arguments_recurse.  */
5077
5078 static void
5079 check_nonnull_arg (void * ARG_UNUSED (ctx), tree param,
5080                    unsigned HOST_WIDE_INT param_num)
5081 {
5082   /* Just skip checking the argument if it's not a pointer.  This can
5083      happen if the "nonnull" attribute was given without an operand
5084      list (which means to check every pointer argument).  */
5085
5086   if (TREE_CODE (TREE_TYPE (param)) != POINTER_TYPE)
5087     return;
5088
5089   if (integer_zerop (param))
5090     warning ("null argument where non-null required (argument %lu)",
5091              (unsigned long) param_num);
5092 }
5093
5094 /* Helper for nonnull attribute handling; fetch the operand number
5095    from the attribute argument list.  */
5096
5097 static bool
5098 get_nonnull_operand (tree arg_num_expr, unsigned HOST_WIDE_INT *valp)
5099 {
5100   /* Strip any conversions from the arg number and verify they
5101      are constants.  */
5102   while (TREE_CODE (arg_num_expr) == NOP_EXPR
5103          || TREE_CODE (arg_num_expr) == CONVERT_EXPR
5104          || TREE_CODE (arg_num_expr) == NON_LVALUE_EXPR)
5105     arg_num_expr = TREE_OPERAND (arg_num_expr, 0);
5106
5107   if (TREE_CODE (arg_num_expr) != INTEGER_CST
5108       || TREE_INT_CST_HIGH (arg_num_expr) != 0)
5109     return false;
5110
5111   *valp = TREE_INT_CST_LOW (arg_num_expr);
5112   return true;
5113 }
5114
5115 /* Handle a "nothrow" attribute; arguments as in
5116    struct attribute_spec.handler.  */
5117
5118 static tree
5119 handle_nothrow_attribute (tree *node, tree name, tree ARG_UNUSED (args),
5120                           int ARG_UNUSED (flags), bool *no_add_attrs)
5121 {
5122   if (TREE_CODE (*node) == FUNCTION_DECL)
5123     TREE_NOTHROW (*node) = 1;
5124   /* ??? TODO: Support types.  */
5125   else
5126     {
5127       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
5128       *no_add_attrs = true;
5129     }
5130
5131   return NULL_TREE;
5132 }
5133
5134 /* Handle a "cleanup" attribute; arguments as in
5135    struct attribute_spec.handler.  */
5136
5137 static tree
5138 handle_cleanup_attribute (tree *node, tree name, tree args,
5139                           int ARG_UNUSED (flags), bool *no_add_attrs)
5140 {
5141   tree decl = *node;
5142   tree cleanup_id, cleanup_decl;
5143
5144   /* ??? Could perhaps support cleanups on TREE_STATIC, much like we do
5145      for global destructors in C++.  This requires infrastructure that
5146      we don't have generically at the moment.  It's also not a feature
5147      we'd be missing too much, since we do have attribute constructor.  */
5148   if (TREE_CODE (decl) != VAR_DECL || TREE_STATIC (decl))
5149     {
5150       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
5151       *no_add_attrs = true;
5152       return NULL_TREE;
5153     }
5154
5155   /* Verify that the argument is a function in scope.  */
5156   /* ??? We could support pointers to functions here as well, if
5157      that was considered desirable.  */
5158   cleanup_id = TREE_VALUE (args);
5159   if (TREE_CODE (cleanup_id) != IDENTIFIER_NODE)
5160     {
5161       error ("cleanup argument not an identifier");
5162       *no_add_attrs = true;
5163       return NULL_TREE;
5164     }
5165   cleanup_decl = lookup_name (cleanup_id);
5166   if (!cleanup_decl || TREE_CODE (cleanup_decl) != FUNCTION_DECL)
5167     {
5168       error ("cleanup argument not a function");
5169       *no_add_attrs = true;
5170       return NULL_TREE;
5171     }
5172
5173   /* That the function has proper type is checked with the
5174      eventual call to build_function_call.  */
5175
5176   return NULL_TREE;
5177 }
5178
5179 /* Handle a "warn_unused_result" attribute.  No special handling.  */
5180
5181 static tree
5182 handle_warn_unused_result_attribute (tree *node, tree name,
5183                                tree ARG_UNUSED (args),
5184                                int ARG_UNUSED (flags), bool *no_add_attrs)
5185 {
5186   /* Ignore the attribute for functions not returning any value.  */
5187   if (VOID_TYPE_P (TREE_TYPE (*node)))
5188     {
5189       warning ("%qs attribute ignored", IDENTIFIER_POINTER (name));
5190       *no_add_attrs = true;
5191     }
5192
5193   return NULL_TREE;
5194 }
5195
5196 /* Handle a "sentinel" attribute.  */
5197
5198 static tree
5199 handle_sentinel_attribute (tree *node, tree name, tree args,
5200                            int ARG_UNUSED (flags), bool *no_add_attrs)
5201 {
5202   tree params = TYPE_ARG_TYPES (*node);
5203
5204   if (!params)
5205     {
5206       warning ("%qs attribute requires prototypes with named arguments",
5207                IDENTIFIER_POINTER (name));
5208       *no_add_attrs = true;
5209     }
5210   else
5211     {
5212       while (TREE_CHAIN (params))
5213         params = TREE_CHAIN (params);
5214
5215       if (VOID_TYPE_P (TREE_VALUE (params)))
5216         {
5217           warning ("%qs attribute only applies to variadic functions",
5218                    IDENTIFIER_POINTER (name));
5219           *no_add_attrs = true;
5220         }
5221     }
5222
5223   if (args)
5224     {
5225       tree position = TREE_VALUE (args);
5226
5227       STRIP_NOPS (position);
5228       if (TREE_CODE (position) != INTEGER_CST)
5229         {
5230           warning ("requested position is not an integer constant");
5231           *no_add_attrs = true;
5232         }
5233       else
5234         {
5235           if (tree_int_cst_lt (position, integer_zero_node))
5236             {
5237               warning ("requested position is less than zero");
5238               *no_add_attrs = true;
5239             }
5240         }
5241     }
5242
5243   return NULL_TREE;
5244 }
5245 \f
5246 /* Check for valid arguments being passed to a function.  */
5247 void
5248 check_function_arguments (tree attrs, tree params)
5249 {
5250   /* Check for null being passed in a pointer argument that must be
5251      non-null.  We also need to do this if format checking is enabled.  */
5252
5253   if (warn_nonnull)
5254     check_function_nonnull (attrs, params);
5255
5256   /* Check for errors in format strings.  */
5257
5258   if (warn_format)
5259     {
5260       check_function_format (attrs, params);
5261       check_function_sentinel (attrs, params);
5262     }
5263 }
5264
5265 /* Generic argument checking recursion routine.  PARAM is the argument to
5266    be checked.  PARAM_NUM is the number of the argument.  CALLBACK is invoked
5267    once the argument is resolved.  CTX is context for the callback.  */
5268 void
5269 check_function_arguments_recurse (void (*callback)
5270                                   (void *, tree, unsigned HOST_WIDE_INT),
5271                                   void *ctx, tree param,
5272                                   unsigned HOST_WIDE_INT param_num)
5273 {
5274   if (TREE_CODE (param) == NOP_EXPR)
5275     {
5276       /* Strip coercion.  */
5277       check_function_arguments_recurse (callback, ctx,
5278                                         TREE_OPERAND (param, 0), param_num);
5279       return;
5280     }
5281
5282   if (TREE_CODE (param) == CALL_EXPR)
5283     {
5284       tree type = TREE_TYPE (TREE_TYPE (TREE_OPERAND (param, 0)));
5285       tree attrs;
5286       bool found_format_arg = false;
5287
5288       /* See if this is a call to a known internationalization function
5289          that modifies a format arg.  Such a function may have multiple
5290          format_arg attributes (for example, ngettext).  */
5291
5292       for (attrs = TYPE_ATTRIBUTES (type);
5293            attrs;
5294            attrs = TREE_CHAIN (attrs))
5295         if (is_attribute_p ("format_arg", TREE_PURPOSE (attrs)))
5296           {
5297             tree inner_args;
5298             tree format_num_expr;
5299             int format_num;
5300             int i;
5301
5302             /* Extract the argument number, which was previously checked
5303                to be valid.  */
5304             format_num_expr = TREE_VALUE (TREE_VALUE (attrs));
5305             while (TREE_CODE (format_num_expr) == NOP_EXPR
5306                    || TREE_CODE (format_num_expr) == CONVERT_EXPR
5307                    || TREE_CODE (format_num_expr) == NON_LVALUE_EXPR)
5308               format_num_expr = TREE_OPERAND (format_num_expr, 0);
5309
5310             gcc_assert (TREE_CODE (format_num_expr) == INTEGER_CST
5311                         && !TREE_INT_CST_HIGH (format_num_expr));
5312
5313             format_num = TREE_INT_CST_LOW (format_num_expr);
5314
5315             for (inner_args = TREE_OPERAND (param, 1), i = 1;
5316                  inner_args != 0;
5317                  inner_args = TREE_CHAIN (inner_args), i++)
5318               if (i == format_num)
5319                 {
5320                   check_function_arguments_recurse (callback, ctx,
5321                                                     TREE_VALUE (inner_args),
5322                                                     param_num);
5323                   found_format_arg = true;
5324                   break;
5325                 }
5326           }
5327
5328       /* If we found a format_arg attribute and did a recursive check,
5329          we are done with checking this argument.  Otherwise, we continue
5330          and this will be considered a non-literal.  */
5331       if (found_format_arg)
5332         return;
5333     }
5334
5335   if (TREE_CODE (param) == COND_EXPR)
5336     {
5337       /* Check both halves of the conditional expression.  */
5338       check_function_arguments_recurse (callback, ctx,
5339                                         TREE_OPERAND (param, 1), param_num);
5340       check_function_arguments_recurse (callback, ctx,
5341                                         TREE_OPERAND (param, 2), param_num);
5342       return;
5343     }
5344
5345   (*callback) (ctx, param, param_num);
5346 }
5347
5348 /* Function to help qsort sort FIELD_DECLs by name order.  */
5349
5350 int
5351 field_decl_cmp (const void *x_p, const void *y_p)
5352 {
5353   const tree *const x = (const tree *const) x_p;
5354   const tree *const y = (const tree *const) y_p;
5355
5356   if (DECL_NAME (*x) == DECL_NAME (*y))
5357     /* A nontype is "greater" than a type.  */
5358     return (TREE_CODE (*y) == TYPE_DECL) - (TREE_CODE (*x) == TYPE_DECL);
5359   if (DECL_NAME (*x) == NULL_TREE)
5360     return -1;
5361   if (DECL_NAME (*y) == NULL_TREE)
5362     return 1;
5363   if (DECL_NAME (*x) < DECL_NAME (*y))
5364     return -1;
5365   return 1;
5366 }
5367
5368 static struct {
5369   gt_pointer_operator new_value;
5370   void *cookie;
5371 } resort_data;
5372
5373 /* This routine compares two fields like field_decl_cmp but using the
5374 pointer operator in resort_data.  */
5375
5376 static int
5377 resort_field_decl_cmp (const void *x_p, const void *y_p)
5378 {
5379   const tree *const x = (const tree *const) x_p;
5380   const tree *const y = (const tree *const) y_p;
5381
5382   if (DECL_NAME (*x) == DECL_NAME (*y))
5383     /* A nontype is "greater" than a type.  */
5384     return (TREE_CODE (*y) == TYPE_DECL) - (TREE_CODE (*x) == TYPE_DECL);
5385   if (DECL_NAME (*x) == NULL_TREE)
5386     return -1;
5387   if (DECL_NAME (*y) == NULL_TREE)
5388     return 1;
5389   {
5390     tree d1 = DECL_NAME (*x);
5391     tree d2 = DECL_NAME (*y);
5392     resort_data.new_value (&d1, resort_data.cookie);
5393     resort_data.new_value (&d2, resort_data.cookie);
5394     if (d1 < d2)
5395       return -1;
5396   }
5397   return 1;
5398 }
5399
5400 /* Resort DECL_SORTED_FIELDS because pointers have been reordered.  */
5401
5402 void
5403 resort_sorted_fields (void *obj,
5404                       void * ARG_UNUSED (orig_obj),
5405                       gt_pointer_operator new_value,
5406                       void *cookie)
5407 {
5408   struct sorted_fields_type *sf = (struct sorted_fields_type *) obj;
5409   resort_data.new_value = new_value;
5410   resort_data.cookie = cookie;
5411   qsort (&sf->elts[0], sf->len, sizeof (tree),
5412          resort_field_decl_cmp);
5413 }
5414
5415 /* Subroutine of c_parse_error.
5416    Return the result of concatenating LHS and RHS. RHS is really
5417    a string literal, its first character is indicated by RHS_START and
5418    RHS_SIZE is its length (including the terminating NUL character).
5419
5420    The caller is responsible for deleting the returned pointer.  */
5421
5422 static char *
5423 catenate_strings (const char *lhs, const char *rhs_start, int rhs_size)
5424 {
5425   const int lhs_size = strlen (lhs);
5426   char *result = XNEWVEC (char, lhs_size + rhs_size);
5427   strncpy (result, lhs, lhs_size);
5428   strncpy (result + lhs_size, rhs_start, rhs_size);
5429   return result;
5430 }
5431
5432 /* Issue the error given by MSGID, indicating that it occurred before
5433    TOKEN, which had the associated VALUE.  */
5434
5435 void
5436 c_parse_error (const char *msgid, enum cpp_ttype token, tree value)
5437 {
5438 #define catenate_messages(M1, M2) catenate_strings ((M1), (M2), sizeof (M2))
5439
5440   char *message = NULL;
5441
5442   if (token == CPP_EOF)
5443     message = catenate_messages (msgid, " at end of input");
5444   else if (token == CPP_CHAR || token == CPP_WCHAR)
5445     {
5446       unsigned int val = TREE_INT_CST_LOW (value);
5447       const char *const ell = (token == CPP_CHAR) ? "" : "L";
5448       if (val <= UCHAR_MAX && ISGRAPH (val))
5449         message = catenate_messages (msgid, " before %s'%c'");
5450       else
5451         message = catenate_messages (msgid, " before %s'\\x%x'");
5452
5453       error (message, ell, val);
5454       free (message);
5455       message = NULL;
5456     }
5457   else if (token == CPP_STRING || token == CPP_WSTRING)
5458     message = catenate_messages (msgid, " before string constant");
5459   else if (token == CPP_NUMBER)
5460     message = catenate_messages (msgid, " before numeric constant");
5461   else if (token == CPP_NAME)
5462     {
5463       message = catenate_messages (msgid, " before %qs");
5464       error (message, IDENTIFIER_POINTER (value));
5465       free (message);
5466       message = NULL;
5467     }
5468   else if (token < N_TTYPES)
5469     {
5470       message = catenate_messages (msgid, " before %qs token");
5471       error (message, cpp_type2name (token));
5472       free (message);
5473       message = NULL;
5474     }
5475   else
5476     error (msgid);
5477
5478   if (message)
5479     {
5480       error (message);
5481       free (message);
5482     }
5483 #undef catenate_messages
5484 }
5485
5486 /* Walk a gimplified function and warn for functions whose return value is
5487    ignored and attribute((warn_unused_result)) is set.  This is done before
5488    inlining, so we don't have to worry about that.  */
5489
5490 void
5491 c_warn_unused_result (tree *top_p)
5492 {
5493   tree t = *top_p;
5494   tree_stmt_iterator i;
5495   tree fdecl, ftype;
5496
5497   switch (TREE_CODE (t))
5498     {
5499     case STATEMENT_LIST:
5500       for (i = tsi_start (*top_p); !tsi_end_p (i); tsi_next (&i))
5501         c_warn_unused_result (tsi_stmt_ptr (i));
5502       break;
5503
5504     case COND_EXPR:
5505       c_warn_unused_result (&COND_EXPR_THEN (t));
5506       c_warn_unused_result (&COND_EXPR_ELSE (t));
5507       break;
5508     case BIND_EXPR:
5509       c_warn_unused_result (&BIND_EXPR_BODY (t));
5510       break;
5511     case TRY_FINALLY_EXPR:
5512     case TRY_CATCH_EXPR:
5513       c_warn_unused_result (&TREE_OPERAND (t, 0));
5514       c_warn_unused_result (&TREE_OPERAND (t, 1));
5515       break;
5516     case CATCH_EXPR:
5517       c_warn_unused_result (&CATCH_BODY (t));
5518       break;
5519     case EH_FILTER_EXPR:
5520       c_warn_unused_result (&EH_FILTER_FAILURE (t));
5521       break;
5522
5523     case CALL_EXPR:
5524       if (TREE_USED (t))
5525         break;
5526
5527       /* This is a naked call, as opposed to a CALL_EXPR nested inside
5528          a MODIFY_EXPR.  All calls whose value is ignored should be
5529          represented like this.  Look for the attribute.  */
5530       fdecl = get_callee_fndecl (t);
5531       if (fdecl)
5532         ftype = TREE_TYPE (fdecl);
5533       else
5534         {
5535           ftype = TREE_TYPE (TREE_OPERAND (t, 0));
5536           /* Look past pointer-to-function to the function type itself.  */
5537           ftype = TREE_TYPE (ftype);
5538         }
5539
5540       if (lookup_attribute ("warn_unused_result", TYPE_ATTRIBUTES (ftype)))
5541         {
5542           if (fdecl)
5543             warning ("%Hignoring return value of %qD, "
5544                      "declared with attribute warn_unused_result",
5545                      EXPR_LOCUS (t), fdecl);
5546           else
5547             warning ("%Hignoring return value of function "
5548                      "declared with attribute warn_unused_result",
5549                      EXPR_LOCUS (t));
5550         }
5551       break;
5552
5553     default:
5554       /* Not a container, not a call, or a call whose value is used.  */
5555       break;
5556     }
5557 }
5558
5559 /* Build the result of __builtin_offsetof.  EXPR is a nested sequence of
5560    component references, with an INDIRECT_REF at the bottom; much like
5561    the traditional rendering of offsetof as a macro.  Returns the folded
5562    and properly cast result.  */
5563
5564 static tree
5565 fold_offsetof_1 (tree expr)
5566 {
5567   enum tree_code code = PLUS_EXPR;
5568   tree base, off, t;
5569
5570   switch (TREE_CODE (expr))
5571     {
5572     case ERROR_MARK:
5573       return expr;
5574
5575     case INDIRECT_REF:
5576       return size_zero_node;
5577
5578     case COMPONENT_REF:
5579       base = fold_offsetof_1 (TREE_OPERAND (expr, 0));
5580       if (base == error_mark_node)
5581         return base;
5582
5583       t = TREE_OPERAND (expr, 1);
5584       if (DECL_C_BIT_FIELD (t))
5585         {
5586           error ("attempt to take address of bit-field structure "
5587                  "member %qs", IDENTIFIER_POINTER (DECL_NAME (t)));
5588           return error_mark_node;
5589         }
5590       off = size_binop (PLUS_EXPR, DECL_FIELD_OFFSET (t),
5591                         size_int (tree_low_cst (DECL_FIELD_BIT_OFFSET (t), 1)
5592                                   / BITS_PER_UNIT));
5593       break;
5594
5595     case ARRAY_REF:
5596       base = fold_offsetof_1 (TREE_OPERAND (expr, 0));
5597       if (base == error_mark_node)
5598         return base;
5599
5600       t = TREE_OPERAND (expr, 1);
5601       if (TREE_CODE (t) == INTEGER_CST && tree_int_cst_sgn (t) < 0)
5602         {
5603           code = MINUS_EXPR;
5604           t = fold (build1 (NEGATE_EXPR, TREE_TYPE (t), t));
5605         }
5606       t = convert (sizetype, t);
5607       off = size_binop (MULT_EXPR, TYPE_SIZE_UNIT (TREE_TYPE (expr)), t);
5608       break;
5609
5610     default:
5611       gcc_unreachable ();
5612     }
5613
5614   return size_binop (code, base, off);
5615 }
5616
5617 tree
5618 fold_offsetof (tree expr)
5619 {
5620   /* Convert back from the internal sizetype to size_t.  */
5621   return convert (size_type_node, fold_offsetof_1 (expr));
5622 }
5623
5624 /* Return nonzero if REF is an lvalue valid for this language;
5625    otherwise, print an error message and return zero.  USE says
5626    how the lvalue is being used and so selects the error message.  */
5627
5628 int
5629 lvalue_or_else (tree ref, enum lvalue_use use)
5630 {
5631   int win = lvalue_p (ref);
5632
5633   if (!win)
5634     {
5635       switch (use)
5636         {
5637         case lv_assign:
5638           error ("invalid lvalue in assignment");
5639           break;
5640         case lv_increment:
5641           error ("invalid lvalue in increment");
5642           break;
5643         case lv_decrement:
5644           error ("invalid lvalue in decrement");
5645           break;
5646         case lv_addressof:
5647           error ("invalid lvalue in unary %<&%>");
5648           break;
5649         case lv_asm:
5650           error ("invalid lvalue in asm statement");
5651           break;
5652         default:
5653           gcc_unreachable ();
5654         }
5655     }
5656
5657   return win;
5658 }
5659
5660 #include "gt-c-common.h"