gcc/targhooks.c

   1 /* Default target hook functions.
   2    Copyright (C) 2003-2013 Free Software Foundation, Inc.
   3
   4 This file is part of GCC.
   5
   6 GCC is free software; you can redistribute it and/or modify it under
   7 the terms of the GNU General Public License as published by the Free
   8 Software Foundation; either version 3, or (at your option) any later
   9 version.
  10
  11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14 for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GCC; see the file COPYING3.  If not see
  18 <http://www.gnu.org/licenses/>.  */
  19
  20 /* The migration of target macros to target hooks works as follows:
  21
  22    1. Create a target hook that uses the existing target macros to
  23       implement the same functionality.
  24
  25    2. Convert all the MI files to use the hook instead of the macro.
  26
  27    3. Repeat for a majority of the remaining target macros.  This will
  28       take some time.
  29
  30    4. Tell target maintainers to start migrating.
  31
  32    5. Eventually convert the backends to override the hook instead of
  33       defining the macros.  This will take some time too.
  34
  35    6. TBD when, poison the macros.  Unmigrated targets will break at
  36       this point.
  37
  38    Note that we expect steps 1-3 to be done by the people that
  39    understand what the MI does with each macro, and step 5 to be done
  40    by the target maintainers for their respective targets.
  41
  42    Note that steps 1 and 2 don't have to be done together, but no
  43    target can override the new hook until step 2 is complete for it.
  44
  45    Once the macros are poisoned, we will revert to the old migration
  46    rules - migrate the macro, callers, and targets all at once.  This
  47    comment can thus be removed at that point.  */
  48
  49 #include "config.h"
  50 #include "system.h"
  51 #include "coretypes.h"
  52 #include "tm.h"
  53 #include "machmode.h"
  54 #include "rtl.h"
  55 #include "tree.h"
  56 #include "expr.h"
  57 #include "output.h"
  58 #include "diagnostic-core.h"
  59 #include "function.h"
  60 #include "target.h"
  61 #include "tm_p.h"
  62 #include "target-def.h"
  63 #include "ggc.h"
  64 #include "hard-reg-set.h"
  65 #include "regs.h"
  66 #include "reload.h"
  67 #include "optabs.h"
  68 #include "recog.h"
  69 #include "intl.h"
  70 #include "opts.h"
  71 #include "tree-flow.h"
  72 #include "tree-ssa-alias.h"
  73
  74
  75 bool
  76 default_legitimate_address_p (enum machine_mode mode ATTRIBUTE_UNUSED,
  77                               rtx addr ATTRIBUTE_UNUSED,
  78                               bool strict ATTRIBUTE_UNUSED)
  79 {
  80 #ifdef GO_IF_LEGITIMATE_ADDRESS
  81   /* Defer to the old implementation using a goto.  */
  82   if (strict)
  83     return strict_memory_address_p (mode, addr);
  84   else
  85     return memory_address_p (mode, addr);
  86 #else
  87   gcc_unreachable ();
  88 #endif
  89 }
  90
  91 void
  92 default_external_libcall (rtx fun ATTRIBUTE_UNUSED)
  93 {
  94 #ifdef ASM_OUTPUT_EXTERNAL_LIBCALL
  95   ASM_OUTPUT_EXTERNAL_LIBCALL(asm_out_file, fun);
  96 #endif
  97 }
  98
  99 int
 100 default_unspec_may_trap_p (const_rtx x, unsigned flags)
 101 {
 102   int i;
 103
 104   /* Any floating arithmetic may trap.  */
 105   if ((SCALAR_FLOAT_MODE_P (GET_MODE (x)) && flag_trapping_math))
 106     return 1;
 107
 108   for (i = 0; i < XVECLEN (x, 0); ++i)
 109     {
 110       if (may_trap_p_1 (XVECEXP (x, 0, i), flags))
 111         return 1;
 112     }
 113
 114   return 0;
 115 }
 116
 117 enum machine_mode
 118 default_promote_function_mode (const_tree type ATTRIBUTE_UNUSED,
 119                                enum machine_mode mode,
 120                                int *punsignedp ATTRIBUTE_UNUSED,
 121                                const_tree funtype ATTRIBUTE_UNUSED,
 122                                int for_return ATTRIBUTE_UNUSED)
 123 {
 124   if (type != NULL_TREE && for_return == 2)
 125     return promote_mode (type, mode, punsignedp);
 126   return mode;
 127 }
 128
 129 enum machine_mode
 130 default_promote_function_mode_always_promote (const_tree type,
 131                                               enum machine_mode mode,
 132                                               int *punsignedp,
 133                                               const_tree funtype ATTRIBUTE_UNUSED,
 134                                               int for_return ATTRIBUTE_UNUSED)
 135 {
 136   return promote_mode (type, mode, punsignedp);
 137 }
 138
 139
 140 enum machine_mode
 141 default_cc_modes_compatible (enum machine_mode m1, enum machine_mode m2)
 142 {
 143   if (m1 == m2)
 144     return m1;
 145   return VOIDmode;
 146 }
 147
 148 bool
 149 default_return_in_memory (const_tree type,
 150                           const_tree fntype ATTRIBUTE_UNUSED)
 151 {
 152   return (TYPE_MODE (type) == BLKmode);
 153 }
 154
 155 rtx
 156 default_legitimize_address (rtx x, rtx orig_x ATTRIBUTE_UNUSED,
 157                             enum machine_mode mode ATTRIBUTE_UNUSED)
 158 {
 159   return x;
 160 }
 161
 162 rtx
 163 default_expand_builtin_saveregs (void)
 164 {
 165   error ("__builtin_saveregs not supported by this target");
 166   return const0_rtx;
 167 }
 168
 169 void
 170 default_setup_incoming_varargs (cumulative_args_t ca ATTRIBUTE_UNUSED,
 171                                 enum machine_mode mode ATTRIBUTE_UNUSED,
 172                                 tree type ATTRIBUTE_UNUSED,
 173                                 int *pretend_arg_size ATTRIBUTE_UNUSED,
 174                                 int second_time ATTRIBUTE_UNUSED)
 175 {
 176 }
 177
 178 /* The default implementation of TARGET_BUILTIN_SETJMP_FRAME_VALUE.  */
 179
 180 rtx
 181 default_builtin_setjmp_frame_value (void)
 182 {
 183   return virtual_stack_vars_rtx;
 184 }
 185
 186 /* Generic hook that takes a CUMULATIVE_ARGS pointer and returns false.  */
 187
 188 bool
 189 hook_bool_CUMULATIVE_ARGS_false (cumulative_args_t ca ATTRIBUTE_UNUSED)
 190 {
 191   return false;
 192 }
 193
 194 bool
 195 default_pretend_outgoing_varargs_named (cumulative_args_t ca ATTRIBUTE_UNUSED)
 196 {
 197   return (targetm.calls.setup_incoming_varargs
 198           != default_setup_incoming_varargs);
 199 }
 200
 201 enum machine_mode
 202 default_eh_return_filter_mode (void)
 203 {
 204   return targetm.unwind_word_mode ();
 205 }
 206
 207 enum machine_mode
 208 default_libgcc_cmp_return_mode (void)
 209 {
 210   return word_mode;
 211 }
 212
 213 enum machine_mode
 214 default_libgcc_shift_count_mode (void)
 215 {
 216   return word_mode;
 217 }
 218
 219 enum machine_mode
 220 default_unwind_word_mode (void)
 221 {
 222   return word_mode;
 223 }
 224
 225 /* The default implementation of TARGET_SHIFT_TRUNCATION_MASK.  */
 226
 227 unsigned HOST_WIDE_INT
 228 default_shift_truncation_mask (enum machine_mode mode)
 229 {
 230   return SHIFT_COUNT_TRUNCATED ? GET_MODE_BITSIZE (mode) - 1 : 0;
 231 }
 232
 233 /* The default implementation of TARGET_MIN_DIVISIONS_FOR_RECIP_MUL.  */
 234
 235 unsigned int
 236 default_min_divisions_for_recip_mul (enum machine_mode mode ATTRIBUTE_UNUSED)
 237 {
 238   return have_insn_for (DIV, mode) ? 3 : 2;
 239 }
 240
 241 /* The default implementation of TARGET_MODE_REP_EXTENDED.  */
 242
 243 int
 244 default_mode_rep_extended (enum machine_mode mode ATTRIBUTE_UNUSED,
 245                            enum machine_mode mode_rep ATTRIBUTE_UNUSED)
 246 {
 247   return UNKNOWN;
 248 }
 249
 250 /* Generic hook that takes a CUMULATIVE_ARGS pointer and returns true.  */
 251
 252 bool
 253 hook_bool_CUMULATIVE_ARGS_true (cumulative_args_t a ATTRIBUTE_UNUSED)
 254 {
 255   return true;
 256 }
 257
 258 /* Return machine mode for non-standard suffix
 259    or VOIDmode if non-standard suffixes are unsupported.  */
 260 enum machine_mode
 261 default_mode_for_suffix (char suffix ATTRIBUTE_UNUSED)
 262 {
 263   return VOIDmode;
 264 }
 265
 266 /* The generic C++ ABI specifies this is a 64-bit value.  */
 267 tree
 268 default_cxx_guard_type (void)
 269 {
 270   return long_long_integer_type_node;
 271 }
 272
 273
 274 /* Returns the size of the cookie to use when allocating an array
 275    whose elements have the indicated TYPE.  Assumes that it is already
 276    known that a cookie is needed.  */
 277
 278 tree
 279 default_cxx_get_cookie_size (tree type)
 280 {
 281   tree cookie_size;
 282
 283   /* We need to allocate an additional max (sizeof (size_t), alignof
 284      (true_type)) bytes.  */
 285   tree sizetype_size;
 286   tree type_align;
 287
 288   sizetype_size = size_in_bytes (sizetype);
 289   type_align = size_int (TYPE_ALIGN_UNIT (type));
 290   if (INT_CST_LT_UNSIGNED (type_align, sizetype_size))
 291     cookie_size = sizetype_size;
 292   else
 293     cookie_size = type_align;
 294
 295   return cookie_size;
 296 }
 297
 298 /* Return true if a parameter must be passed by reference.  This version
 299    of the TARGET_PASS_BY_REFERENCE hook uses just MUST_PASS_IN_STACK.  */
 300
 301 bool
 302 hook_pass_by_reference_must_pass_in_stack (cumulative_args_t c ATTRIBUTE_UNUSED,
 303         enum machine_mode mode ATTRIBUTE_UNUSED, const_tree type ATTRIBUTE_UNUSED,
 304         bool named_arg ATTRIBUTE_UNUSED)
 305 {
 306   return targetm.calls.must_pass_in_stack (mode, type);
 307 }
 308
 309 /* Return true if a parameter follows callee copies conventions.  This
 310    version of the hook is true for all named arguments.  */
 311
 312 bool
 313 hook_callee_copies_named (cumulative_args_t ca ATTRIBUTE_UNUSED,
 314                           enum machine_mode mode ATTRIBUTE_UNUSED,
 315                           const_tree type ATTRIBUTE_UNUSED, bool named)
 316 {
 317   return named;
 318 }
 319
 320 /* Emit to STREAM the assembler syntax for insn operand X.  */
 321
 322 void
 323 default_print_operand (FILE *stream ATTRIBUTE_UNUSED, rtx x ATTRIBUTE_UNUSED,
 324                        int code ATTRIBUTE_UNUSED)
 325 {
 326 #ifdef PRINT_OPERAND
 327   PRINT_OPERAND (stream, x, code);
 328 #else
 329   gcc_unreachable ();
 330 #endif
 331 }
 332
 333 /* Emit to STREAM the assembler syntax for an insn operand whose memory
 334    address is X.  */
 335
 336 void
 337 default_print_operand_address (FILE *stream ATTRIBUTE_UNUSED,
 338                                rtx x ATTRIBUTE_UNUSED)
 339 {
 340 #ifdef PRINT_OPERAND_ADDRESS
 341   PRINT_OPERAND_ADDRESS (stream, x);
 342 #else
 343   gcc_unreachable ();
 344 #endif
 345 }
 346
 347 /* Return true if CODE is a valid punctuation character for the
 348    `print_operand' hook.  */
 349
 350 bool
 351 default_print_operand_punct_valid_p (unsigned char code ATTRIBUTE_UNUSED)
 352 {
 353 #ifdef PRINT_OPERAND_PUNCT_VALID_P
 354   return PRINT_OPERAND_PUNCT_VALID_P (code);
 355 #else
 356   return false;
 357 #endif
 358 }
 359
 360 /* The default implementation of TARGET_MANGLE_ASSEMBLER_NAME.  */
 361 tree
 362 default_mangle_assembler_name (const char *name ATTRIBUTE_UNUSED)
 363 {
 364   const char *skipped = name + (*name == '*' ? 1 : 0);
 365   const char *stripped = targetm.strip_name_encoding (skipped);
 366   if (*name != '*' && user_label_prefix[0])
 367     stripped = ACONCAT ((user_label_prefix, stripped, NULL));
 368   return get_identifier (stripped);
 369 }
 370
 371 /* True if MODE is valid for the target.  By "valid", we mean able to
 372    be manipulated in non-trivial ways.  In particular, this means all
 373    the arithmetic is supported.
 374
 375    By default we guess this means that any C type is supported.  If
 376    we can't map the mode back to a type that would be available in C,
 377    then reject it.  Special case, here, is the double-word arithmetic
 378    supported by optabs.c.  */
 379
 380 bool
 381 default_scalar_mode_supported_p (enum machine_mode mode)
 382 {
 383   int precision = GET_MODE_PRECISION (mode);
 384
 385   switch (GET_MODE_CLASS (mode))
 386     {
 387     case MODE_PARTIAL_INT:
 388     case MODE_INT:
 389       if (precision == CHAR_TYPE_SIZE)
 390         return true;
 391       if (precision == SHORT_TYPE_SIZE)
 392         return true;
 393       if (precision == INT_TYPE_SIZE)
 394         return true;
 395       if (precision == LONG_TYPE_SIZE)
 396         return true;
 397       if (precision == LONG_LONG_TYPE_SIZE)
 398         return true;
 399       if (precision == 2 * BITS_PER_WORD)
 400         return true;
 401       return false;
 402
 403     case MODE_FLOAT:
 404       if (precision == FLOAT_TYPE_SIZE)
 405         return true;
 406       if (precision == DOUBLE_TYPE_SIZE)
 407         return true;
 408       if (precision == LONG_DOUBLE_TYPE_SIZE)
 409         return true;
 410       return false;
 411
 412     case MODE_DECIMAL_FLOAT:
 413     case MODE_FRACT:
 414     case MODE_UFRACT:
 415     case MODE_ACCUM:
 416     case MODE_UACCUM:
 417       return false;
 418
 419     default:
 420       gcc_unreachable ();
 421     }
 422 }
 423
 424 /* Make some target macros useable by target-independent code.  */
 425 bool
 426 targhook_words_big_endian (void)
 427 {
 428   return !!WORDS_BIG_ENDIAN;
 429 }
 430
 431 bool
 432 targhook_float_words_big_endian (void)
 433 {
 434   return !!FLOAT_WORDS_BIG_ENDIAN;
 435 }
 436
 437 /* True if the target supports decimal floating point.  */
 438
 439 bool
 440 default_decimal_float_supported_p (void)
 441 {
 442   return ENABLE_DECIMAL_FLOAT;
 443 }
 444
 445 /* True if the target supports fixed-point arithmetic.  */
 446
 447 bool
 448 default_fixed_point_supported_p (void)
 449 {
 450   return ENABLE_FIXED_POINT;
 451 }
 452
 453 /* NULL if INSN insn is valid within a low-overhead loop, otherwise returns
 454    an error message.
 455
 456    This function checks whether a given INSN is valid within a low-overhead
 457    loop.  If INSN is invalid it returns the reason for that, otherwise it
 458    returns NULL. A called function may clobber any special registers required
 459    for low-overhead looping. Additionally, some targets (eg, PPC) use the count
 460    register for branch on table instructions. We reject the doloop pattern in
 461    these cases.  */
 462
 463 const char *
 464 default_invalid_within_doloop (const_rtx insn)
 465 {
 466   if (CALL_P (insn))
 467     return "Function call in loop.";
 468
 469   if (JUMP_TABLE_DATA_P (insn))
 470     return "Computed branch in the loop.";
 471
 472   return NULL;
 473 }
 474
 475 /* Mapping of builtin functions to vectorized variants.  */
 476
 477 tree
 478 default_builtin_vectorized_function (tree fndecl ATTRIBUTE_UNUSED,
 479                                      tree type_out ATTRIBUTE_UNUSED,
 480                                      tree type_in ATTRIBUTE_UNUSED)
 481 {
 482   return NULL_TREE;
 483 }
 484
 485 /* Vectorized conversion.  */
 486
 487 tree
 488 default_builtin_vectorized_conversion (unsigned int code ATTRIBUTE_UNUSED,
 489                                        tree dest_type ATTRIBUTE_UNUSED,
 490                                        tree src_type ATTRIBUTE_UNUSED)
 491 {
 492   return NULL_TREE;
 493 }
 494
 495 /* Default vectorizer cost model values.  */
 496
 497 int
 498 default_builtin_vectorization_cost (enum vect_cost_for_stmt type_of_cost,
 499                                     tree vectype,
 500                                     int misalign ATTRIBUTE_UNUSED)
 501 {
 502   unsigned elements;
 503
 504   switch (type_of_cost)
 505     {
 506       case scalar_stmt:
 507       case scalar_load:
 508       case scalar_store:
 509       case vector_stmt:
 510       case vector_load:
 511       case vector_store:
 512       case vec_to_scalar:
 513       case scalar_to_vec:
 514       case cond_branch_not_taken:
 515       case vec_perm:
 516       case vec_promote_demote:
 517         return 1;
 518
 519       case unaligned_load:
 520       case unaligned_store:
 521         return 2;
 522
 523       case cond_branch_taken:
 524         return 3;
 525
 526       case vec_construct:
 527         elements = TYPE_VECTOR_SUBPARTS (vectype);
 528         return elements / 2 + 1;
 529
 530       default:
 531         gcc_unreachable ();
 532     }
 533 }
 534
 535 /* Reciprocal.  */
 536
 537 tree
 538 default_builtin_reciprocal (unsigned int fn ATTRIBUTE_UNUSED,
 539                             bool md_fn ATTRIBUTE_UNUSED,
 540                             bool sqrt ATTRIBUTE_UNUSED)
 541 {
 542   return NULL_TREE;
 543 }
 544
 545 bool
 546 hook_bool_CUMULATIVE_ARGS_mode_tree_bool_false (
 547         cumulative_args_t ca ATTRIBUTE_UNUSED,
 548         enum machine_mode mode ATTRIBUTE_UNUSED,
 549         const_tree type ATTRIBUTE_UNUSED, bool named ATTRIBUTE_UNUSED)
 550 {
 551   return false;
 552 }
 553
 554 bool
 555 hook_bool_CUMULATIVE_ARGS_mode_tree_bool_true (
 556         cumulative_args_t ca ATTRIBUTE_UNUSED,
 557         enum machine_mode mode ATTRIBUTE_UNUSED,
 558         const_tree type ATTRIBUTE_UNUSED, bool named ATTRIBUTE_UNUSED)
 559 {
 560   return true;
 561 }
 562
 563 int
 564 hook_int_CUMULATIVE_ARGS_mode_tree_bool_0 (
 565         cumulative_args_t ca ATTRIBUTE_UNUSED,
 566         enum machine_mode mode ATTRIBUTE_UNUSED,
 567         tree type ATTRIBUTE_UNUSED, bool named ATTRIBUTE_UNUSED)
 568 {
 569   return 0;
 570 }
 571
 572 void
 573 default_function_arg_advance (cumulative_args_t ca ATTRIBUTE_UNUSED,
 574                               enum machine_mode mode ATTRIBUTE_UNUSED,
 575                               const_tree type ATTRIBUTE_UNUSED,
 576                               bool named ATTRIBUTE_UNUSED)
 577 {
 578   gcc_unreachable ();
 579 }
 580
 581 rtx
 582 default_function_arg (cumulative_args_t ca ATTRIBUTE_UNUSED,
 583                       enum machine_mode mode ATTRIBUTE_UNUSED,
 584                       const_tree type ATTRIBUTE_UNUSED,
 585                       bool named ATTRIBUTE_UNUSED)
 586 {
 587   gcc_unreachable ();
 588 }
 589
 590 rtx
 591 default_function_incoming_arg (cumulative_args_t ca ATTRIBUTE_UNUSED,
 592                                enum machine_mode mode ATTRIBUTE_UNUSED,
 593                                const_tree type ATTRIBUTE_UNUSED,
 594                                bool named ATTRIBUTE_UNUSED)
 595 {
 596   gcc_unreachable ();
 597 }
 598
 599 unsigned int
 600 default_function_arg_boundary (enum machine_mode mode ATTRIBUTE_UNUSED,
 601                                const_tree type ATTRIBUTE_UNUSED)
 602 {
 603   return PARM_BOUNDARY;
 604 }
 605
 606 unsigned int
 607 default_function_arg_round_boundary (enum machine_mode mode ATTRIBUTE_UNUSED,
 608                                      const_tree type ATTRIBUTE_UNUSED)
 609 {
 610   return PARM_BOUNDARY;
 611 }
 612
 613 void
 614 hook_void_bitmap (bitmap regs ATTRIBUTE_UNUSED)
 615 {
 616 }
 617
 618 const char *
 619 hook_invalid_arg_for_unprototyped_fn (
 620         const_tree typelist ATTRIBUTE_UNUSED,
 621         const_tree funcdecl ATTRIBUTE_UNUSED,
 622         const_tree val ATTRIBUTE_UNUSED)
 623 {
 624   return NULL;
 625 }
 626
 627 /* Initialize the stack protection decls.  */
 628
 629 /* Stack protection related decls living in libgcc.  */
 630 static GTY(()) tree stack_chk_guard_decl;
 631
 632 tree
 633 default_stack_protect_guard (void)
 634 {
 635   tree t = stack_chk_guard_decl;
 636
 637   if (t == NULL)
 638     {
 639       rtx x;
 640
 641       t = build_decl (UNKNOWN_LOCATION,
 642                       VAR_DECL, get_identifier ("__stack_chk_guard"),
 643                       ptr_type_node);
 644       TREE_STATIC (t) = 1;
 645       TREE_PUBLIC (t) = 1;
 646       DECL_EXTERNAL (t) = 1;
 647       TREE_USED (t) = 1;
 648       TREE_THIS_VOLATILE (t) = 1;
 649       DECL_ARTIFICIAL (t) = 1;
 650       DECL_IGNORED_P (t) = 1;
 651
 652       /* Do not share RTL as the declaration is visible outside of
 653          current function.  */
 654       x = DECL_RTL (t);
 655       RTX_FLAG (x, used) = 1;
 656
 657       stack_chk_guard_decl = t;
 658     }
 659
 660   return t;
 661 }
 662
 663 static GTY(()) tree stack_chk_fail_decl;
 664
 665 tree
 666 default_external_stack_protect_fail (void)
 667 {
 668   tree t = stack_chk_fail_decl;
 669
 670   if (t == NULL_TREE)
 671     {
 672       t = build_function_type_list (void_type_node, NULL_TREE);
 673       t = build_decl (UNKNOWN_LOCATION,
 674                       FUNCTION_DECL, get_identifier ("__stack_chk_fail"), t);
 675       TREE_STATIC (t) = 1;
 676       TREE_PUBLIC (t) = 1;
 677       DECL_EXTERNAL (t) = 1;
 678       TREE_USED (t) = 1;
 679       TREE_THIS_VOLATILE (t) = 1;
 680       TREE_NOTHROW (t) = 1;
 681       DECL_ARTIFICIAL (t) = 1;
 682       DECL_IGNORED_P (t) = 1;
 683       DECL_VISIBILITY (t) = VISIBILITY_DEFAULT;
 684       DECL_VISIBILITY_SPECIFIED (t) = 1;
 685
 686       stack_chk_fail_decl = t;
 687     }
 688
 689   return build_call_expr (t, 0);
 690 }
 691
 692 tree
 693 default_hidden_stack_protect_fail (void)
 694 {
 695 #ifndef HAVE_GAS_HIDDEN
 696   return default_external_stack_protect_fail ();
 697 #else
 698   tree t = stack_chk_fail_decl;
 699
 700   if (!flag_pic)
 701     return default_external_stack_protect_fail ();
 702
 703   if (t == NULL_TREE)
 704     {
 705       t = build_function_type_list (void_type_node, NULL_TREE);
 706       t = build_decl (UNKNOWN_LOCATION, FUNCTION_DECL,
 707                       get_identifier ("__stack_chk_fail_local"), t);
 708       TREE_STATIC (t) = 1;
 709       TREE_PUBLIC (t) = 1;
 710       DECL_EXTERNAL (t) = 1;
 711       TREE_USED (t) = 1;
 712       TREE_THIS_VOLATILE (t) = 1;
 713       TREE_NOTHROW (t) = 1;
 714       DECL_ARTIFICIAL (t) = 1;
 715       DECL_IGNORED_P (t) = 1;
 716       DECL_VISIBILITY_SPECIFIED (t) = 1;
 717       DECL_VISIBILITY (t) = VISIBILITY_HIDDEN;
 718
 719       stack_chk_fail_decl = t;
 720     }
 721
 722   return build_call_expr (t, 0);
 723 #endif
 724 }
 725
 726 bool
 727 hook_bool_const_rtx_commutative_p (const_rtx x,
 728                                    int outer_code ATTRIBUTE_UNUSED)
 729 {
 730   return COMMUTATIVE_P (x);
 731 }
 732
 733 rtx
 734 default_function_value (const_tree ret_type ATTRIBUTE_UNUSED,
 735                         const_tree fn_decl_or_type,
 736                         bool outgoing ATTRIBUTE_UNUSED)
 737 {
 738   /* The old interface doesn't handle receiving the function type.  */
 739   if (fn_decl_or_type
 740       && !DECL_P (fn_decl_or_type))
 741     fn_decl_or_type = NULL;
 742
 743 #ifdef FUNCTION_VALUE
 744   return FUNCTION_VALUE (ret_type, fn_decl_or_type);
 745 #else
 746   gcc_unreachable ();
 747 #endif
 748 }
 749
 750 rtx
 751 default_libcall_value (enum machine_mode mode ATTRIBUTE_UNUSED,
 752                        const_rtx fun ATTRIBUTE_UNUSED)
 753 {
 754 #ifdef LIBCALL_VALUE
 755   return LIBCALL_VALUE (mode);
 756 #else
 757   gcc_unreachable ();
 758 #endif
 759 }
 760
 761 /* The default hook for TARGET_FUNCTION_VALUE_REGNO_P.  */
 762
 763 bool
 764 default_function_value_regno_p (const unsigned int regno ATTRIBUTE_UNUSED)
 765 {
 766 #ifdef FUNCTION_VALUE_REGNO_P
 767   return FUNCTION_VALUE_REGNO_P (regno);
 768 #else
 769   gcc_unreachable ();
 770 #endif
 771 }
 772
 773 rtx
 774 default_internal_arg_pointer (void)
 775 {
 776   /* If the reg that the virtual arg pointer will be translated into is
 777      not a fixed reg or is the stack pointer, make a copy of the virtual
 778      arg pointer, and address parms via the copy.  The frame pointer is
 779      considered fixed even though it is not marked as such.  */
 780   if ((ARG_POINTER_REGNUM == STACK_POINTER_REGNUM
 781        || ! (fixed_regs[ARG_POINTER_REGNUM]
 782              || ARG_POINTER_REGNUM == FRAME_POINTER_REGNUM)))
 783     return copy_to_reg (virtual_incoming_args_rtx);
 784   else
 785     return virtual_incoming_args_rtx;
 786 }
 787
 788 rtx
 789 default_static_chain (const_tree fndecl, bool incoming_p)
 790 {
 791   if (!DECL_STATIC_CHAIN (fndecl))
 792     return NULL;
 793
 794   if (incoming_p)
 795     {
 796 #ifdef STATIC_CHAIN_INCOMING_REGNUM
 797       return gen_rtx_REG (Pmode, STATIC_CHAIN_INCOMING_REGNUM);
 798 #endif
 799     }
 800
 801 #ifdef STATIC_CHAIN_REGNUM
 802   return gen_rtx_REG (Pmode, STATIC_CHAIN_REGNUM);
 803 #endif
 804
 805   {
 806     static bool issued_error;
 807     if (!issued_error)
 808       {
 809         issued_error = true;
 810         sorry ("nested functions not supported on this target");
 811       }
 812
 813     /* It really doesn't matter what we return here, so long at it
 814        doesn't cause the rest of the compiler to crash.  */
 815     return gen_rtx_MEM (Pmode, stack_pointer_rtx);
 816   }
 817 }
 818
 819 void
 820 default_trampoline_init (rtx ARG_UNUSED (m_tramp), tree ARG_UNUSED (t_func),
 821                          rtx ARG_UNUSED (r_chain))
 822 {
 823   sorry ("nested function trampolines not supported on this target");
 824 }
 825
 826 int
 827 default_return_pops_args (tree fundecl ATTRIBUTE_UNUSED,
 828                           tree funtype ATTRIBUTE_UNUSED,
 829                           int size ATTRIBUTE_UNUSED)
 830 {
 831   return 0;
 832 }
 833
 834 reg_class_t
 835 default_branch_target_register_class (void)
 836 {
 837   return NO_REGS;
 838 }
 839
 840 extern bool
 841 default_lra_p (void)
 842 {
 843   return false;
 844 }
 845
 846 int
 847 default_register_priority (int hard_regno ATTRIBUTE_UNUSED)
 848 {
 849   return 0;
 850 }
 851
 852 extern bool
 853 default_different_addr_displacement_p (void)
 854 {
 855   return false;
 856 }
 857
 858 reg_class_t
 859 default_secondary_reload (bool in_p ATTRIBUTE_UNUSED, rtx x ATTRIBUTE_UNUSED,
 860                           reg_class_t reload_class_i ATTRIBUTE_UNUSED,
 861                           enum machine_mode reload_mode ATTRIBUTE_UNUSED,
 862                           secondary_reload_info *sri)
 863 {
 864   enum reg_class rclass = NO_REGS;
 865   enum reg_class reload_class = (enum reg_class) reload_class_i;
 866
 867   if (sri->prev_sri && sri->prev_sri->t_icode != CODE_FOR_nothing)
 868     {
 869       sri->icode = sri->prev_sri->t_icode;
 870       return NO_REGS;
 871     }
 872 #ifdef SECONDARY_INPUT_RELOAD_CLASS
 873   if (in_p)
 874     rclass = SECONDARY_INPUT_RELOAD_CLASS (reload_class, reload_mode, x);
 875 #endif
 876 #ifdef SECONDARY_OUTPUT_RELOAD_CLASS
 877   if (! in_p)
 878     rclass = SECONDARY_OUTPUT_RELOAD_CLASS (reload_class, reload_mode, x);
 879 #endif
 880   if (rclass != NO_REGS)
 881     {
 882       enum insn_code icode
 883         = direct_optab_handler (in_p ? reload_in_optab : reload_out_optab,
 884                                 reload_mode);
 885
 886       if (icode != CODE_FOR_nothing
 887           && !insn_operand_matches (icode, in_p, x))
 888         icode = CODE_FOR_nothing;
 889       else if (icode != CODE_FOR_nothing)
 890         {
 891           const char *insn_constraint, *scratch_constraint;
 892           char insn_letter, scratch_letter;
 893           enum reg_class insn_class, scratch_class;
 894
 895           gcc_assert (insn_data[(int) icode].n_operands == 3);
 896           insn_constraint = insn_data[(int) icode].operand[!in_p].constraint;
 897           if (!*insn_constraint)
 898             insn_class = ALL_REGS;
 899           else
 900             {
 901               if (in_p)
 902                 {
 903                   gcc_assert (*insn_constraint == '=');
 904                   insn_constraint++;
 905                 }
 906               insn_letter = *insn_constraint;
 907               insn_class
 908                 = (insn_letter == 'r' ? GENERAL_REGS
 909                    : REG_CLASS_FROM_CONSTRAINT ((unsigned char) insn_letter,
 910                                                 insn_constraint));
 911               gcc_assert (insn_class != NO_REGS);
 912             }
 913
 914           scratch_constraint = insn_data[(int) icode].operand[2].constraint;
 915           /* The scratch register's constraint must start with "=&",
 916              except for an input reload, where only "=" is necessary,
 917              and where it might be beneficial to re-use registers from
 918              the input.  */
 919           gcc_assert (scratch_constraint[0] == '='
 920                       && (in_p || scratch_constraint[1] == '&'));
 921           scratch_constraint++;
 922           if (*scratch_constraint == '&')
 923             scratch_constraint++;
 924           scratch_letter = *scratch_constraint;
 925           scratch_class
 926             = (scratch_letter == 'r' ? GENERAL_REGS
 927                : REG_CLASS_FROM_CONSTRAINT ((unsigned char) scratch_letter,
 928                                             scratch_constraint));
 929
 930           if (reg_class_subset_p (reload_class, insn_class))
 931             {
 932               gcc_assert (scratch_class == rclass);
 933               rclass = NO_REGS;
 934             }
 935           else
 936             rclass = insn_class;
 937
 938         }
 939       if (rclass == NO_REGS)
 940         sri->icode = icode;
 941       else
 942         sri->t_icode = icode;
 943     }
 944   return rclass;
 945 }
 946
 947 /* By default, if flag_pic is true, then neither local nor global relocs
 948    should be placed in readonly memory.  */
 949
 950 int
 951 default_reloc_rw_mask (void)
 952 {
 953   return flag_pic ? 3 : 0;
 954 }
 955
 956 /* By default, do no modification. */
 957 tree default_mangle_decl_assembler_name (tree decl ATTRIBUTE_UNUSED,
 958                                          tree id)
 959 {
 960    return id;
 961 }
 962
 963 /* Default to natural alignment for vector types.  */
 964 HOST_WIDE_INT
 965 default_vector_alignment (const_tree type)
 966 {
 967   return tree_low_cst (TYPE_SIZE (type), 0);
 968 }
 969
 970 bool
 971 default_builtin_vector_alignment_reachable (const_tree type, bool is_packed)
 972 {
 973   if (is_packed)
 974     return false;
 975
 976   /* Assuming that types whose size is > pointer-size are not guaranteed to be
 977      naturally aligned.  */
 978   if (tree_int_cst_compare (TYPE_SIZE (type), bitsize_int (POINTER_SIZE)) > 0)
 979     return false;
 980
 981   /* Assuming that types whose size is <= pointer-size
 982      are naturally aligned.  */
 983   return true;
 984 }
 985
 986 /* By default, assume that a target supports any factor of misalignment
 987    memory access if it supports movmisalign patten.
 988    is_packed is true if the memory access is defined in a packed struct.  */
 989 bool
 990 default_builtin_support_vector_misalignment (enum machine_mode mode,
 991                                              const_tree type
 992                                              ATTRIBUTE_UNUSED,
 993                                              int misalignment
 994                                              ATTRIBUTE_UNUSED,
 995                                              bool is_packed
 996                                              ATTRIBUTE_UNUSED)
 997 {
 998   if (optab_handler (movmisalign_optab, mode) != CODE_FOR_nothing)
 999     return true;
1000   return false;
1001 }
1002
1003 /* By default, only attempt to parallelize bitwise operations, and
1004    possibly adds/subtracts using bit-twiddling.  */
1005
1006 enum machine_mode
1007 default_preferred_simd_mode (enum machine_mode mode ATTRIBUTE_UNUSED)
1008 {
1009   return word_mode;
1010 }
1011
1012 /* By default only the size derived from the preferred vector mode
1013    is tried.  */
1014
1015 unsigned int
1016 default_autovectorize_vector_sizes (void)
1017 {
1018   return 0;
1019 }
1020
1021 /* By default, the cost model accumulates three separate costs (prologue,
1022    loop body, and epilogue) for a vectorized loop or block.  So allocate an
1023    array of three unsigned ints, set it to zero, and return its address.  */
1024
1025 void *
1026 default_init_cost (struct loop *loop_info ATTRIBUTE_UNUSED)
1027 {
1028   unsigned *cost = XNEWVEC (unsigned, 3);
1029   cost[vect_prologue] = cost[vect_body] = cost[vect_epilogue] = 0;
1030   return cost;
1031 }
1032
1033 /* By default, the cost model looks up the cost of the given statement
1034    kind and mode, multiplies it by the occurrence count, accumulates
1035    it into the cost specified by WHERE, and returns the cost added.  */
1036
1037 unsigned
1038 default_add_stmt_cost (void *data, int count, enum vect_cost_for_stmt kind,
1039                        struct _stmt_vec_info *stmt_info, int misalign,
1040                        enum vect_cost_model_location where)
1041 {
1042   unsigned *cost = (unsigned *) data;
1043   unsigned retval = 0;
1044
1045   if (flag_vect_cost_model)
1046     {
1047       tree vectype = stmt_info ? stmt_vectype (stmt_info) : NULL_TREE;
1048       int stmt_cost = default_builtin_vectorization_cost (kind, vectype,
1049                                                           misalign);
1050       /* Statements in an inner loop relative to the loop being
1051          vectorized are weighted more heavily.  The value here is
1052          arbitrary and could potentially be improved with analysis.  */
1053       if (where == vect_body && stmt_info && stmt_in_inner_loop_p (stmt_info))
1054         count *= 50;  /* FIXME.  */
1055
1056       retval = (unsigned) (count * stmt_cost);
1057       cost[where] += retval;
1058     }
1059
1060   return retval;
1061 }
1062
1063 /* By default, the cost model just returns the accumulated costs.  */
1064
1065 void
1066 default_finish_cost (void *data, unsigned *prologue_cost,
1067                      unsigned *body_cost, unsigned *epilogue_cost)
1068 {
1069   unsigned *cost = (unsigned *) data;
1070   *prologue_cost = cost[vect_prologue];
1071   *body_cost     = cost[vect_body];
1072   *epilogue_cost = cost[vect_epilogue];
1073 }
1074
1075 /* Free the cost data.  */
1076
1077 void
1078 default_destroy_cost_data (void *data)
1079 {
1080   free (data);
1081 }
1082
1083 /* Determine whether or not a pointer mode is valid. Assume defaults
1084    of ptr_mode or Pmode - can be overridden.  */
1085 bool
1086 default_valid_pointer_mode (enum machine_mode mode)
1087 {
1088   return (mode == ptr_mode || mode == Pmode);
1089 }
1090
1091 /* Determine whether the memory reference specified by REF may alias
1092    the C libraries errno location.  */
1093 bool
1094 default_ref_may_alias_errno (ao_ref *ref)
1095 {
1096   tree base = ao_ref_base (ref);
1097   /* The default implementation assumes the errno location is
1098      a declaration of type int or is always accessed via a
1099      pointer to int.  We assume that accesses to errno are
1100      not deliberately obfuscated (even in conforming ways).  */
1101   if (TYPE_UNSIGNED (TREE_TYPE (base))
1102       || TYPE_MODE (TREE_TYPE (base)) != TYPE_MODE (integer_type_node))
1103     return false;
1104   /* The default implementation assumes an errno location
1105      declaration is never defined in the current compilation unit.  */
1106   if (DECL_P (base)
1107       && !TREE_STATIC (base))
1108     return true;
1109   else if (TREE_CODE (base) == MEM_REF
1110            && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME)
1111     {
1112       struct ptr_info_def *pi = SSA_NAME_PTR_INFO (TREE_OPERAND (base, 0));
1113       return !pi || pi->pt.anything || pi->pt.nonlocal;
1114     }
1115   return false;
1116 }
1117
1118 /* Return the mode for a pointer to a given ADDRSPACE, defaulting to ptr_mode
1119    for the generic address space only.  */
1120
1121 enum machine_mode
1122 default_addr_space_pointer_mode (addr_space_t addrspace ATTRIBUTE_UNUSED)
1123 {
1124   gcc_assert (ADDR_SPACE_GENERIC_P (addrspace));
1125   return ptr_mode;
1126 }
1127
1128 /* Return the mode for an address in a given ADDRSPACE, defaulting to Pmode
1129    for the generic address space only.  */
1130
1131 enum machine_mode
1132 default_addr_space_address_mode (addr_space_t addrspace ATTRIBUTE_UNUSED)
1133 {
1134   gcc_assert (ADDR_SPACE_GENERIC_P (addrspace));
1135   return Pmode;
1136 }
1137
1138 /* Named address space version of valid_pointer_mode.  */
1139
1140 bool
1141 default_addr_space_valid_pointer_mode (enum machine_mode mode, addr_space_t as)
1142 {
1143   if (!ADDR_SPACE_GENERIC_P (as))
1144     return (mode == targetm.addr_space.pointer_mode (as)
1145             || mode == targetm.addr_space.address_mode (as));
1146
1147   return targetm.valid_pointer_mode (mode);
1148 }
1149
1150 /* Some places still assume that all pointer or address modes are the
1151    standard Pmode and ptr_mode.  These optimizations become invalid if
1152    the target actually supports multiple different modes.  For now,
1153    we disable such optimizations on such targets, using this function.  */
1154
1155 bool
1156 target_default_pointer_address_modes_p (void)
1157 {
1158   if (targetm.addr_space.address_mode != default_addr_space_address_mode)
1159     return false;
1160   if (targetm.addr_space.pointer_mode != default_addr_space_pointer_mode)
1161     return false;
1162
1163   return true;
1164 }
1165
1166 /* Named address space version of legitimate_address_p.  */
1167
1168 bool
1169 default_addr_space_legitimate_address_p (enum machine_mode mode, rtx mem,
1170                                          bool strict, addr_space_t as)
1171 {
1172   if (!ADDR_SPACE_GENERIC_P (as))
1173     gcc_unreachable ();
1174
1175   return targetm.legitimate_address_p (mode, mem, strict);
1176 }
1177
1178 /* Named address space version of LEGITIMIZE_ADDRESS.  */
1179
1180 rtx
1181 default_addr_space_legitimize_address (rtx x, rtx oldx,
1182                                        enum machine_mode mode, addr_space_t as)
1183 {
1184   if (!ADDR_SPACE_GENERIC_P (as))
1185     return x;
1186
1187   return targetm.legitimize_address (x, oldx, mode);
1188 }
1189
1190 /* The default hook for determining if one named address space is a subset of
1191    another and to return which address space to use as the common address
1192    space.  */
1193
1194 bool
1195 default_addr_space_subset_p (addr_space_t subset, addr_space_t superset)
1196 {
1197   return (subset == superset);
1198 }
1199
1200 /* The default hook for TARGET_ADDR_SPACE_CONVERT. This hook should never be
1201    called for targets with only a generic address space.  */
1202
1203 rtx
1204 default_addr_space_convert (rtx op ATTRIBUTE_UNUSED,
1205                             tree from_type ATTRIBUTE_UNUSED,
1206                             tree to_type ATTRIBUTE_UNUSED)
1207 {
1208   gcc_unreachable ();
1209 }
1210
1211 bool
1212 default_hard_regno_scratch_ok (unsigned int regno ATTRIBUTE_UNUSED)
1213 {
1214   return true;
1215 }
1216
1217 /* The default implementation of TARGET_MODE_DEPENDENT_ADDRESS_P.  */
1218
1219 bool
1220 default_mode_dependent_address_p (const_rtx addr ATTRIBUTE_UNUSED,
1221                                   addr_space_t addrspace ATTRIBUTE_UNUSED)
1222 {
1223   return false;
1224 }
1225
1226 bool
1227 default_target_option_valid_attribute_p (tree ARG_UNUSED (fndecl),
1228                                          tree ARG_UNUSED (name),
1229                                          tree ARG_UNUSED (args),
1230                                          int ARG_UNUSED (flags))
1231 {
1232   warning (OPT_Wattributes,
1233            "target attribute is not supported on this machine");
1234
1235   return false;
1236 }
1237
1238 bool
1239 default_target_option_pragma_parse (tree ARG_UNUSED (args),
1240                                     tree ARG_UNUSED (pop_target))
1241 {
1242   warning (OPT_Wpragmas,
1243            "#pragma GCC target is not supported for this machine");
1244
1245   return false;
1246 }
1247
1248 bool
1249 default_target_can_inline_p (tree caller, tree callee)
1250 {
1251   bool ret = false;
1252   tree callee_opts = DECL_FUNCTION_SPECIFIC_TARGET (callee);
1253   tree caller_opts = DECL_FUNCTION_SPECIFIC_TARGET (caller);
1254
1255   /* If callee has no option attributes, then it is ok to inline */
1256   if (!callee_opts)
1257     ret = true;
1258
1259   /* If caller has no option attributes, but callee does then it is not ok to
1260      inline */
1261   else if (!caller_opts)
1262     ret = false;
1263
1264   /* If both caller and callee have attributes, assume that if the
1265      pointer is different, the two functions have different target
1266      options since build_target_option_node uses a hash table for the
1267      options.  */
1268   else
1269     ret = (callee_opts == caller_opts);
1270
1271   return ret;
1272 }
1273
1274 #ifndef HAVE_casesi
1275 # define HAVE_casesi 0
1276 #endif
1277
1278 /* If the machine does not have a case insn that compares the bounds,
1279    this means extra overhead for dispatch tables, which raises the
1280    threshold for using them.  */
1281
1282 unsigned int
1283 default_case_values_threshold (void)
1284 {
1285   return (HAVE_casesi ? 4 : 5);
1286 }
1287
1288 bool
1289 default_have_conditional_execution (void)
1290 {
1291 #ifdef HAVE_conditional_execution
1292   return HAVE_conditional_execution;
1293 #else
1294   return false;
1295 #endif
1296 }
1297
1298 tree
1299 default_builtin_tm_load_store (tree ARG_UNUSED (type))
1300 {
1301   return NULL_TREE;
1302 }
1303
1304 /* Compute cost of moving registers to/from memory.  */
1305
1306 int
1307 default_memory_move_cost (enum machine_mode mode ATTRIBUTE_UNUSED,
1308                           reg_class_t rclass ATTRIBUTE_UNUSED,
1309                           bool in ATTRIBUTE_UNUSED)
1310 {
1311 #ifndef MEMORY_MOVE_COST
1312     return (4 + memory_move_secondary_cost (mode, (enum reg_class) rclass, in));
1313 #else
1314     return MEMORY_MOVE_COST (mode, (enum reg_class) rclass, in);
1315 #endif
1316 }
1317
1318 /* Compute cost of moving data from a register of class FROM to one of
1319    TO, using MODE.  */
1320
1321 int
1322 default_register_move_cost (enum machine_mode mode ATTRIBUTE_UNUSED,
1323                             reg_class_t from ATTRIBUTE_UNUSED,
1324                             reg_class_t to ATTRIBUTE_UNUSED)
1325 {
1326 #ifndef REGISTER_MOVE_COST
1327   return 2;
1328 #else
1329   return REGISTER_MOVE_COST (mode, (enum reg_class) from, (enum reg_class) to);
1330 #endif
1331 }
1332
1333 bool
1334 default_profile_before_prologue (void)
1335 {
1336 #ifdef PROFILE_BEFORE_PROLOGUE
1337   return true;
1338 #else
1339   return false;
1340 #endif
1341 }
1342
1343 /* The default implementation of TARGET_PREFERRED_RELOAD_CLASS.  */
1344
1345 reg_class_t
1346 default_preferred_reload_class (rtx x ATTRIBUTE_UNUSED,
1347                                 reg_class_t rclass)
1348 {
1349 #ifdef PREFERRED_RELOAD_CLASS
1350   return (reg_class_t) PREFERRED_RELOAD_CLASS (x, (enum reg_class) rclass);
1351 #else
1352   return rclass;
1353 #endif
1354 }
1355
1356 /* The default implementation of TARGET_OUTPUT_PREFERRED_RELOAD_CLASS.  */
1357
1358 reg_class_t
1359 default_preferred_output_reload_class (rtx x ATTRIBUTE_UNUSED,
1360                                        reg_class_t rclass)
1361 {
1362   return rclass;
1363 }
1364
1365 /* The default implementation of TARGET_PREFERRED_RENAME_CLASS.  */
1366 reg_class_t
1367 default_preferred_rename_class (reg_class_t rclass ATTRIBUTE_UNUSED)
1368 {
1369   return NO_REGS;
1370 }
1371
1372 /* The default implementation of TARGET_CLASS_LIKELY_SPILLED_P.  */
1373
1374 bool
1375 default_class_likely_spilled_p (reg_class_t rclass)
1376 {
1377   return (reg_class_size[(int) rclass] == 1);
1378 }
1379
1380 /* The default implementation of TARGET_CLASS_MAX_NREGS.  */
1381
1382 unsigned char
1383 default_class_max_nregs (reg_class_t rclass ATTRIBUTE_UNUSED,
1384                          enum machine_mode mode ATTRIBUTE_UNUSED)
1385 {
1386 #ifdef CLASS_MAX_NREGS
1387   return (unsigned char) CLASS_MAX_NREGS ((enum reg_class) rclass, mode);
1388 #else
1389   return ((GET_MODE_SIZE (mode) + UNITS_PER_WORD - 1) / UNITS_PER_WORD);
1390 #endif
1391 }
1392
1393 /* Determine the debugging unwind mechanism for the target.  */
1394
1395 enum unwind_info_type
1396 default_debug_unwind_info (void)
1397 {
1398   /* If the target wants to force the use of dwarf2 unwind info, let it.  */
1399   /* ??? Change all users to the hook, then poison this.  */
1400 #ifdef DWARF2_FRAME_INFO
1401   if (DWARF2_FRAME_INFO)
1402     return UI_DWARF2;
1403 #endif
1404
1405   /* Otherwise, only turn it on if dwarf2 debugging is enabled.  */
1406 #ifdef DWARF2_DEBUGGING_INFO
1407   if (write_symbols == DWARF2_DEBUG || write_symbols == VMS_AND_DWARF2_DEBUG)
1408     return UI_DWARF2;
1409 #endif
1410
1411   return UI_NONE;
1412 }
1413
1414 /* To be used by targets where reg_raw_mode doesn't return the right
1415    mode for registers used in apply_builtin_return and apply_builtin_arg.  */
1416
1417 enum machine_mode
1418 default_get_reg_raw_mode(int regno)
1419 {
1420   return reg_raw_mode[regno];
1421 }
1422
1423 /* Return true if the state of option OPTION should be stored in PCH files
1424    and checked by default_pch_valid_p.  Store the option's current state
1425    in STATE if so.  */
1426
1427 static inline bool
1428 option_affects_pch_p (int option, struct cl_option_state *state)
1429 {
1430   if ((cl_options[option].flags & CL_TARGET) == 0)
1431     return false;
1432   if (option_flag_var (option, &global_options) == &target_flags)
1433     if (targetm.check_pch_target_flags)
1434       return false;
1435   return get_option_state (&global_options, option, state);
1436 }
1437
1438 /* Default version of get_pch_validity.
1439    By default, every flag difference is fatal; that will be mostly right for
1440    most targets, but completely right for very few.  */
1441
1442 void *
1443 default_get_pch_validity (size_t *sz)
1444 {
1445   struct cl_option_state state;
1446   size_t i;
1447   char *result, *r;
1448
1449   *sz = 2;
1450   if (targetm.check_pch_target_flags)
1451     *sz += sizeof (target_flags);
1452   for (i = 0; i < cl_options_count; i++)
1453     if (option_affects_pch_p (i, &state))
1454       *sz += state.size;
1455
1456   result = r = XNEWVEC (char, *sz);
1457   r[0] = flag_pic;
1458   r[1] = flag_pie;
1459   r += 2;
1460   if (targetm.check_pch_target_flags)
1461     {
1462       memcpy (r, &target_flags, sizeof (target_flags));
1463       r += sizeof (target_flags);
1464     }
1465
1466   for (i = 0; i < cl_options_count; i++)
1467     if (option_affects_pch_p (i, &state))
1468       {
1469         memcpy (r, state.data, state.size);
1470         r += state.size;
1471       }
1472
1473   return result;
1474 }
1475
1476 /* Return a message which says that a PCH file was created with a different
1477    setting of OPTION.  */
1478
1479 static const char *
1480 pch_option_mismatch (const char *option)
1481 {
1482   char *r;
1483
1484   asprintf (&r, _("created and used with differing settings of '%s'"), option);
1485   if (r == NULL)
1486     return _("out of memory");
1487   return r;
1488 }
1489
1490 /* Default version of pch_valid_p.  */
1491
1492 const char *
1493 default_pch_valid_p (const void *data_p, size_t len)
1494 {
1495   struct cl_option_state state;
1496   const char *data = (const char *)data_p;
1497   size_t i;
1498
1499   /* -fpic and -fpie also usually make a PCH invalid.  */
1500   if (data[0] != flag_pic)
1501     return _("created and used with different settings of -fpic");
1502   if (data[1] != flag_pie)
1503     return _("created and used with different settings of -fpie");
1504   data += 2;
1505
1506   /* Check target_flags.  */
1507   if (targetm.check_pch_target_flags)
1508     {
1509       int tf;
1510       const char *r;
1511
1512       memcpy (&tf, data, sizeof (target_flags));
1513       data += sizeof (target_flags);
1514       len -= sizeof (target_flags);
1515       r = targetm.check_pch_target_flags (tf);
1516       if (r != NULL)
1517         return r;
1518     }
1519
1520   for (i = 0; i < cl_options_count; i++)
1521     if (option_affects_pch_p (i, &state))
1522       {
1523         if (memcmp (data, state.data, state.size) != 0)
1524           return pch_option_mismatch (cl_options[i].opt_text);
1525         data += state.size;
1526         len -= state.size;
1527       }
1528
1529   return NULL;
1530 }
1531
1532 /* Default version of member_type_forces_blk.  */
1533
1534 bool
1535 default_member_type_forces_blk (const_tree, enum machine_mode)
1536 {
1537   return false;
1538 }
1539
1540 /* Default version of canonicalize_comparison.  */
1541
1542 void
1543 default_canonicalize_comparison (int *, rtx *, rtx *, bool)
1544 {
1545 }
1546
1547 #include "gt-targhooks.h"