gcc/targhooks.c

   1 /* Default target hook functions.
   2    Copyright (C) 2003, 2004, 2005, 2007, 2008, 2009, 2010, 2011
   3    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 3, 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 COPYING3.  If not see
  19 <http://www.gnu.org/licenses/>.  */
  20
  21 /* The migration of target macros to target hooks works as follows:
  22
  23    1. Create a target hook that uses the existing target macros to
  24       implement the same functionality.
  25
  26    2. Convert all the MI files to use the hook instead of the macro.
  27
  28    3. Repeat for a majority of the remaining target macros.  This will
  29       take some time.
  30
  31    4. Tell target maintainers to start migrating.
  32
  33    5. Eventually convert the backends to override the hook instead of
  34       defining the macros.  This will take some time too.
  35
  36    6. TBD when, poison the macros.  Unmigrated targets will break at
  37       this point.
  38
  39    Note that we expect steps 1-3 to be done by the people that
  40    understand what the MI does with each macro, and step 5 to be done
  41    by the target maintainers for their respective targets.
  42
  43    Note that steps 1 and 2 don't have to be done together, but no
  44    target can override the new hook until step 2 is complete for it.
  45
  46    Once the macros are poisoned, we will revert to the old migration
  47    rules - migrate the macro, callers, and targets all at once.  This
  48    comment can thus be removed at that point.  */
  49
  50 #include "config.h"
  51 #include "system.h"
  52 #include "coretypes.h"
  53 #include "tm.h"
  54 #include "machmode.h"
  55 #include "rtl.h"
  56 #include "tree.h"
  57 #include "expr.h"
  58 #include "output.h"
  59 #include "diagnostic-core.h"
  60 #include "function.h"
  61 #include "target.h"
  62 #include "tm_p.h"
  63 #include "target-def.h"
  64 #include "ggc.h"
  65 #include "hard-reg-set.h"
  66 #include "regs.h"
  67 #include "reload.h"
  68 #include "optabs.h"
  69 #include "recog.h"
  70 #include "intl.h"
  71 #include "opts.h"
  72 #include "tree-flow.h"
  73 #include "tree-ssa-alias.h"
  74
  75
  76 bool
  77 default_legitimate_address_p (enum machine_mode mode ATTRIBUTE_UNUSED,
  78                               rtx addr ATTRIBUTE_UNUSED,
  79                               bool strict ATTRIBUTE_UNUSED)
  80 {
  81 #ifdef GO_IF_LEGITIMATE_ADDRESS
  82   /* Defer to the old implementation using a goto.  */
  83   if (strict)
  84     return strict_memory_address_p (mode, addr);
  85   else
  86     return memory_address_p (mode, addr);
  87 #else
  88   gcc_unreachable ();
  89 #endif
  90 }
  91
  92 void
  93 default_external_libcall (rtx fun ATTRIBUTE_UNUSED)
  94 {
  95 #ifdef ASM_OUTPUT_EXTERNAL_LIBCALL
  96   ASM_OUTPUT_EXTERNAL_LIBCALL(asm_out_file, fun);
  97 #endif
  98 }
  99
 100 int
 101 default_unspec_may_trap_p (const_rtx x, unsigned flags)
 102 {
 103   int i;
 104
 105   if (GET_CODE (x) == UNSPEC_VOLATILE
 106       /* Any floating arithmetic may trap.  */
 107       || (SCALAR_FLOAT_MODE_P (GET_MODE (x))
 108           && flag_trapping_math))
 109     return 1;
 110
 111   for (i = 0; i < XVECLEN (x, 0); ++i)
 112     {
 113       if (may_trap_p_1 (XVECEXP (x, 0, i), flags))
 114         return 1;
 115     }
 116
 117   return 0;
 118 }
 119
 120 enum machine_mode
 121 default_promote_function_mode (const_tree type ATTRIBUTE_UNUSED,
 122                                enum machine_mode mode,
 123                                int *punsignedp ATTRIBUTE_UNUSED,
 124                                const_tree funtype ATTRIBUTE_UNUSED,
 125                                int for_return ATTRIBUTE_UNUSED)
 126 {
 127   if (for_return == 2)
 128     return promote_mode (type, mode, punsignedp);
 129   return mode;
 130 }
 131
 132 enum machine_mode
 133 default_promote_function_mode_always_promote (const_tree type,
 134                                               enum machine_mode mode,
 135                                               int *punsignedp,
 136                                               const_tree funtype ATTRIBUTE_UNUSED,
 137                                               int for_return ATTRIBUTE_UNUSED)
 138 {
 139   return promote_mode (type, mode, punsignedp);
 140 }
 141
 142
 143 enum machine_mode
 144 default_cc_modes_compatible (enum machine_mode m1, enum machine_mode m2)
 145 {
 146   if (m1 == m2)
 147     return m1;
 148   return VOIDmode;
 149 }
 150
 151 bool
 152 default_return_in_memory (const_tree type,
 153                           const_tree fntype ATTRIBUTE_UNUSED)
 154 {
 155   return (TYPE_MODE (type) == BLKmode);
 156 }
 157
 158 rtx
 159 default_legitimize_address (rtx x, rtx orig_x ATTRIBUTE_UNUSED,
 160                             enum machine_mode mode ATTRIBUTE_UNUSED)
 161 {
 162   return x;
 163 }
 164
 165 rtx
 166 default_expand_builtin_saveregs (void)
 167 {
 168   error ("__builtin_saveregs not supported by this target");
 169   return const0_rtx;
 170 }
 171
 172 void
 173 default_setup_incoming_varargs (CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
 174                                 enum machine_mode mode ATTRIBUTE_UNUSED,
 175                                 tree type ATTRIBUTE_UNUSED,
 176                                 int *pretend_arg_size ATTRIBUTE_UNUSED,
 177                                 int second_time ATTRIBUTE_UNUSED)
 178 {
 179 }
 180
 181 /* The default implementation of TARGET_BUILTIN_SETJMP_FRAME_VALUE.  */
 182
 183 rtx
 184 default_builtin_setjmp_frame_value (void)
 185 {
 186   return virtual_stack_vars_rtx;
 187 }
 188
 189 /* Generic hook that takes a CUMULATIVE_ARGS pointer and returns false.  */
 190
 191 bool
 192 hook_bool_CUMULATIVE_ARGS_false (CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED)
 193 {
 194   return false;
 195 }
 196
 197 bool
 198 default_pretend_outgoing_varargs_named (CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED)
 199 {
 200   return (targetm.calls.setup_incoming_varargs
 201           != default_setup_incoming_varargs);
 202 }
 203
 204 enum machine_mode
 205 default_eh_return_filter_mode (void)
 206 {
 207   return targetm.unwind_word_mode ();
 208 }
 209
 210 enum machine_mode
 211 default_libgcc_cmp_return_mode (void)
 212 {
 213   return word_mode;
 214 }
 215
 216 enum machine_mode
 217 default_libgcc_shift_count_mode (void)
 218 {
 219   return word_mode;
 220 }
 221
 222 enum machine_mode
 223 default_unwind_word_mode (void)
 224 {
 225   return word_mode;
 226 }
 227
 228 /* The default implementation of TARGET_SHIFT_TRUNCATION_MASK.  */
 229
 230 unsigned HOST_WIDE_INT
 231 default_shift_truncation_mask (enum machine_mode mode)
 232 {
 233   return SHIFT_COUNT_TRUNCATED ? GET_MODE_BITSIZE (mode) - 1 : 0;
 234 }
 235
 236 /* The default implementation of TARGET_MIN_DIVISIONS_FOR_RECIP_MUL.  */
 237
 238 unsigned int
 239 default_min_divisions_for_recip_mul (enum machine_mode mode ATTRIBUTE_UNUSED)
 240 {
 241   return have_insn_for (DIV, mode) ? 3 : 2;
 242 }
 243
 244 /* The default implementation of TARGET_MODE_REP_EXTENDED.  */
 245
 246 int
 247 default_mode_rep_extended (enum machine_mode mode ATTRIBUTE_UNUSED,
 248                            enum machine_mode mode_rep ATTRIBUTE_UNUSED)
 249 {
 250   return UNKNOWN;
 251 }
 252
 253 /* Generic hook that takes a CUMULATIVE_ARGS pointer and returns true.  */
 254
 255 bool
 256 hook_bool_CUMULATIVE_ARGS_true (CUMULATIVE_ARGS * a ATTRIBUTE_UNUSED)
 257 {
 258   return true;
 259 }
 260
 261 /* Return machine mode for non-standard suffix
 262    or VOIDmode if non-standard suffixes are unsupported.  */
 263 enum machine_mode
 264 default_mode_for_suffix (char suffix ATTRIBUTE_UNUSED)
 265 {
 266   return VOIDmode;
 267 }
 268
 269 /* The generic C++ ABI specifies this is a 64-bit value.  */
 270 tree
 271 default_cxx_guard_type (void)
 272 {
 273   return long_long_integer_type_node;
 274 }
 275
 276
 277 /* Returns the size of the cookie to use when allocating an array
 278    whose elements have the indicated TYPE.  Assumes that it is already
 279    known that a cookie is needed.  */
 280
 281 tree
 282 default_cxx_get_cookie_size (tree type)
 283 {
 284   tree cookie_size;
 285
 286   /* We need to allocate an additional max (sizeof (size_t), alignof
 287      (true_type)) bytes.  */
 288   tree sizetype_size;
 289   tree type_align;
 290
 291   sizetype_size = size_in_bytes (sizetype);
 292   type_align = size_int (TYPE_ALIGN_UNIT (type));
 293   if (INT_CST_LT_UNSIGNED (type_align, sizetype_size))
 294     cookie_size = sizetype_size;
 295   else
 296     cookie_size = type_align;
 297
 298   return cookie_size;
 299 }
 300
 301 /* Return true if a parameter must be passed by reference.  This version
 302    of the TARGET_PASS_BY_REFERENCE hook uses just MUST_PASS_IN_STACK.  */
 303
 304 bool
 305 hook_pass_by_reference_must_pass_in_stack (CUMULATIVE_ARGS *c ATTRIBUTE_UNUSED,
 306         enum machine_mode mode ATTRIBUTE_UNUSED, const_tree type ATTRIBUTE_UNUSED,
 307         bool named_arg ATTRIBUTE_UNUSED)
 308 {
 309   return targetm.calls.must_pass_in_stack (mode, type);
 310 }
 311
 312 /* Return true if a parameter follows callee copies conventions.  This
 313    version of the hook is true for all named arguments.  */
 314
 315 bool
 316 hook_callee_copies_named (CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
 317                           enum machine_mode mode ATTRIBUTE_UNUSED,
 318                           const_tree type ATTRIBUTE_UNUSED, bool named)
 319 {
 320   return named;
 321 }
 322
 323 /* Emit to STREAM the assembler syntax for insn operand X.  */
 324
 325 void
 326 default_print_operand (FILE *stream ATTRIBUTE_UNUSED, rtx x ATTRIBUTE_UNUSED,
 327                        int code ATTRIBUTE_UNUSED)
 328 {
 329 #ifdef PRINT_OPERAND
 330   PRINT_OPERAND (stream, x, code);
 331 #else
 332   gcc_unreachable ();
 333 #endif
 334 }
 335
 336 /* Emit to STREAM the assembler syntax for an insn operand whose memory
 337    address is X.  */
 338
 339 void
 340 default_print_operand_address (FILE *stream ATTRIBUTE_UNUSED,
 341                                rtx x ATTRIBUTE_UNUSED)
 342 {
 343 #ifdef PRINT_OPERAND_ADDRESS
 344   PRINT_OPERAND_ADDRESS (stream, x);
 345 #else
 346   gcc_unreachable ();
 347 #endif
 348 }
 349
 350 /* Return true if CODE is a valid punctuation character for the
 351    `print_operand' hook.  */
 352
 353 bool
 354 default_print_operand_punct_valid_p (unsigned char code ATTRIBUTE_UNUSED)
 355 {
 356 #ifdef PRINT_OPERAND_PUNCT_VALID_P
 357   return PRINT_OPERAND_PUNCT_VALID_P (code);
 358 #else
 359   return false;
 360 #endif
 361 }
 362
 363 /* The default implementation of TARGET_MANGLE_ASSEMBLER_NAME.  */
 364 tree
 365 default_mangle_assembler_name (const char *name ATTRIBUTE_UNUSED)
 366 {
 367   const char *skipped = name + (*name == '*' ? 1 : 0);
 368   const char *stripped = targetm.strip_name_encoding (skipped);
 369   if (*name != '*' && user_label_prefix[0])
 370     stripped = ACONCAT ((user_label_prefix, stripped, NULL));
 371   return get_identifier (stripped);
 372 }
 373
 374 /* The default implementation of TARGET_ASM_OUTPUT_ADDR_CONST_EXTRA.  */
 375
 376 bool
 377 default_asm_output_addr_const_extra (FILE *file ATTRIBUTE_UNUSED,
 378                                      rtx x ATTRIBUTE_UNUSED)
 379 {
 380 #ifdef OUTPUT_ADDR_CONST_EXTRA
 381   OUTPUT_ADDR_CONST_EXTRA (file, x, fail);
 382   return true;
 383
 384 fail:
 385 #endif
 386   return false;
 387 }
 388
 389 /* True if MODE is valid for the target.  By "valid", we mean able to
 390    be manipulated in non-trivial ways.  In particular, this means all
 391    the arithmetic is supported.
 392
 393    By default we guess this means that any C type is supported.  If
 394    we can't map the mode back to a type that would be available in C,
 395    then reject it.  Special case, here, is the double-word arithmetic
 396    supported by optabs.c.  */
 397
 398 bool
 399 default_scalar_mode_supported_p (enum machine_mode mode)
 400 {
 401   int precision = GET_MODE_PRECISION (mode);
 402
 403   switch (GET_MODE_CLASS (mode))
 404     {
 405     case MODE_PARTIAL_INT:
 406     case MODE_INT:
 407       if (precision == CHAR_TYPE_SIZE)
 408         return true;
 409       if (precision == SHORT_TYPE_SIZE)
 410         return true;
 411       if (precision == INT_TYPE_SIZE)
 412         return true;
 413       if (precision == LONG_TYPE_SIZE)
 414         return true;
 415       if (precision == LONG_LONG_TYPE_SIZE)
 416         return true;
 417       if (precision == 2 * BITS_PER_WORD)
 418         return true;
 419       return false;
 420
 421     case MODE_FLOAT:
 422       if (precision == FLOAT_TYPE_SIZE)
 423         return true;
 424       if (precision == DOUBLE_TYPE_SIZE)
 425         return true;
 426       if (precision == LONG_DOUBLE_TYPE_SIZE)
 427         return true;
 428       return false;
 429
 430     case MODE_DECIMAL_FLOAT:
 431     case MODE_FRACT:
 432     case MODE_UFRACT:
 433     case MODE_ACCUM:
 434     case MODE_UACCUM:
 435       return false;
 436
 437     default:
 438       gcc_unreachable ();
 439     }
 440 }
 441
 442 /* Make some target macros useable by target-independent code.  */
 443 bool
 444 targhook_words_big_endian (void)
 445 {
 446   return !!WORDS_BIG_ENDIAN;
 447 }
 448
 449 bool
 450 targhook_float_words_big_endian (void)
 451 {
 452   return !!FLOAT_WORDS_BIG_ENDIAN;
 453 }
 454
 455 /* True if the target supports decimal floating point.  */
 456
 457 bool
 458 default_decimal_float_supported_p (void)
 459 {
 460   return ENABLE_DECIMAL_FLOAT;
 461 }
 462
 463 /* True if the target supports fixed-point arithmetic.  */
 464
 465 bool
 466 default_fixed_point_supported_p (void)
 467 {
 468   return ENABLE_FIXED_POINT;
 469 }
 470
 471 /* NULL if INSN insn is valid within a low-overhead loop, otherwise returns
 472    an error message.
 473
 474    This function checks whether a given INSN is valid within a low-overhead
 475    loop.  If INSN is invalid it returns the reason for that, otherwise it
 476    returns NULL. A called function may clobber any special registers required
 477    for low-overhead looping. Additionally, some targets (eg, PPC) use the count
 478    register for branch on table instructions. We reject the doloop pattern in
 479    these cases.  */
 480
 481 const char *
 482 default_invalid_within_doloop (const_rtx insn)
 483 {
 484   if (CALL_P (insn))
 485     return "Function call in loop.";
 486
 487   if (JUMP_TABLE_DATA_P (insn))
 488     return "Computed branch in the loop.";
 489
 490   return NULL;
 491 }
 492
 493 /* Mapping of builtin functions to vectorized variants.  */
 494
 495 tree
 496 default_builtin_vectorized_function (tree fndecl ATTRIBUTE_UNUSED,
 497                                      tree type_out ATTRIBUTE_UNUSED,
 498                                      tree type_in ATTRIBUTE_UNUSED)
 499 {
 500   return NULL_TREE;
 501 }
 502
 503 /* Vectorized conversion.  */
 504
 505 tree
 506 default_builtin_vectorized_conversion (unsigned int code ATTRIBUTE_UNUSED,
 507                                        tree dest_type ATTRIBUTE_UNUSED,
 508                                        tree src_type ATTRIBUTE_UNUSED)
 509 {
 510   return NULL_TREE;
 511 }
 512
 513 /* Default vectorizer cost model values.  */
 514
 515 int
 516 default_builtin_vectorization_cost (enum vect_cost_for_stmt type_of_cost,
 517                                     tree vectype ATTRIBUTE_UNUSED,
 518                                     int misalign ATTRIBUTE_UNUSED)
 519 {
 520   switch (type_of_cost)
 521     {
 522       case scalar_stmt:
 523       case scalar_load:
 524       case scalar_store:
 525       case vector_stmt:
 526       case vector_load:
 527       case vector_store:
 528       case vec_to_scalar:
 529       case scalar_to_vec:
 530       case cond_branch_not_taken:
 531       case vec_perm:
 532         return 1;
 533
 534       case unaligned_load:
 535       case unaligned_store:
 536         return 2;
 537
 538       case cond_branch_taken:
 539         return 3;
 540
 541       default:
 542         gcc_unreachable ();
 543     }
 544 }
 545
 546 /* Reciprocal.  */
 547
 548 tree
 549 default_builtin_reciprocal (unsigned int fn ATTRIBUTE_UNUSED,
 550                             bool md_fn ATTRIBUTE_UNUSED,
 551                             bool sqrt ATTRIBUTE_UNUSED)
 552 {
 553   return NULL_TREE;
 554 }
 555
 556 bool
 557 hook_bool_CUMULATIVE_ARGS_mode_tree_bool_false (
 558         CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
 559         enum machine_mode mode ATTRIBUTE_UNUSED,
 560         const_tree type ATTRIBUTE_UNUSED, bool named ATTRIBUTE_UNUSED)
 561 {
 562   return false;
 563 }
 564
 565 bool
 566 hook_bool_CUMULATIVE_ARGS_mode_tree_bool_true (
 567         CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
 568         enum machine_mode mode ATTRIBUTE_UNUSED,
 569         const_tree type ATTRIBUTE_UNUSED, bool named ATTRIBUTE_UNUSED)
 570 {
 571   return true;
 572 }
 573
 574 int
 575 hook_int_CUMULATIVE_ARGS_mode_tree_bool_0 (
 576         CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
 577         enum machine_mode mode ATTRIBUTE_UNUSED,
 578         tree type ATTRIBUTE_UNUSED, bool named ATTRIBUTE_UNUSED)
 579 {
 580   return 0;
 581 }
 582
 583 void
 584 default_function_arg_advance (CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
 585                               enum machine_mode mode ATTRIBUTE_UNUSED,
 586                               const_tree type ATTRIBUTE_UNUSED,
 587                               bool named ATTRIBUTE_UNUSED)
 588 {
 589 #ifdef FUNCTION_ARG_ADVANCE
 590   CUMULATIVE_ARGS args = *ca;
 591   FUNCTION_ARG_ADVANCE (args, mode, CONST_CAST_TREE (type), named);
 592   *ca = args;
 593 #else
 594   gcc_unreachable ();
 595 #endif
 596 }
 597
 598 rtx
 599 default_function_arg (CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
 600                       enum machine_mode mode ATTRIBUTE_UNUSED,
 601                       const_tree type ATTRIBUTE_UNUSED,
 602                       bool named ATTRIBUTE_UNUSED)
 603 {
 604 #ifdef FUNCTION_ARG
 605   return FUNCTION_ARG (*ca, mode, CONST_CAST_TREE (type), named);
 606 #else
 607   gcc_unreachable ();
 608 #endif
 609 }
 610
 611 rtx
 612 default_function_incoming_arg (CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
 613                                enum machine_mode mode ATTRIBUTE_UNUSED,
 614                                const_tree type ATTRIBUTE_UNUSED,
 615                                bool named ATTRIBUTE_UNUSED)
 616 {
 617 #ifdef FUNCTION_INCOMING_ARG
 618   return FUNCTION_INCOMING_ARG (*ca, mode, CONST_CAST_TREE (type), named);
 619 #else
 620   gcc_unreachable ();
 621 #endif
 622 }
 623
 624 unsigned int
 625 default_function_arg_boundary (enum machine_mode mode ATTRIBUTE_UNUSED,
 626                                const_tree type ATTRIBUTE_UNUSED)
 627 {
 628   return PARM_BOUNDARY;
 629 }
 630
 631 void
 632 hook_void_bitmap (bitmap regs ATTRIBUTE_UNUSED)
 633 {
 634 }
 635
 636 const char *
 637 hook_invalid_arg_for_unprototyped_fn (
 638         const_tree typelist ATTRIBUTE_UNUSED,
 639         const_tree funcdecl ATTRIBUTE_UNUSED,
 640         const_tree val ATTRIBUTE_UNUSED)
 641 {
 642   return NULL;
 643 }
 644
 645 /* Initialize the stack protection decls.  */
 646
 647 /* Stack protection related decls living in libgcc.  */
 648 static GTY(()) tree stack_chk_guard_decl;
 649
 650 tree
 651 default_stack_protect_guard (void)
 652 {
 653   tree t = stack_chk_guard_decl;
 654
 655   if (t == NULL)
 656     {
 657       rtx x;
 658
 659       t = build_decl (UNKNOWN_LOCATION,
 660                       VAR_DECL, get_identifier ("__stack_chk_guard"),
 661                       ptr_type_node);
 662       TREE_STATIC (t) = 1;
 663       TREE_PUBLIC (t) = 1;
 664       DECL_EXTERNAL (t) = 1;
 665       TREE_USED (t) = 1;
 666       TREE_THIS_VOLATILE (t) = 1;
 667       DECL_ARTIFICIAL (t) = 1;
 668       DECL_IGNORED_P (t) = 1;
 669
 670       /* Do not share RTL as the declaration is visible outside of
 671          current function.  */
 672       x = DECL_RTL (t);
 673       RTX_FLAG (x, used) = 1;
 674
 675       stack_chk_guard_decl = t;
 676     }
 677
 678   return t;
 679 }
 680
 681 static GTY(()) tree stack_chk_fail_decl;
 682
 683 tree
 684 default_external_stack_protect_fail (void)
 685 {
 686   tree t = stack_chk_fail_decl;
 687
 688   if (t == NULL_TREE)
 689     {
 690       t = build_function_type_list (void_type_node, NULL_TREE);
 691       t = build_decl (UNKNOWN_LOCATION,
 692                       FUNCTION_DECL, get_identifier ("__stack_chk_fail"), t);
 693       TREE_STATIC (t) = 1;
 694       TREE_PUBLIC (t) = 1;
 695       DECL_EXTERNAL (t) = 1;
 696       TREE_USED (t) = 1;
 697       TREE_THIS_VOLATILE (t) = 1;
 698       TREE_NOTHROW (t) = 1;
 699       DECL_ARTIFICIAL (t) = 1;
 700       DECL_IGNORED_P (t) = 1;
 701       DECL_VISIBILITY (t) = VISIBILITY_DEFAULT;
 702       DECL_VISIBILITY_SPECIFIED (t) = 1;
 703
 704       stack_chk_fail_decl = t;
 705     }
 706
 707   return build_call_expr (t, 0);
 708 }
 709
 710 tree
 711 default_hidden_stack_protect_fail (void)
 712 {
 713 #ifndef HAVE_GAS_HIDDEN
 714   return default_external_stack_protect_fail ();
 715 #else
 716   tree t = stack_chk_fail_decl;
 717
 718   if (!flag_pic)
 719     return default_external_stack_protect_fail ();
 720
 721   if (t == NULL_TREE)
 722     {
 723       t = build_function_type_list (void_type_node, NULL_TREE);
 724       t = build_decl (UNKNOWN_LOCATION, FUNCTION_DECL,
 725                       get_identifier ("__stack_chk_fail_local"), t);
 726       TREE_STATIC (t) = 1;
 727       TREE_PUBLIC (t) = 1;
 728       DECL_EXTERNAL (t) = 1;
 729       TREE_USED (t) = 1;
 730       TREE_THIS_VOLATILE (t) = 1;
 731       TREE_NOTHROW (t) = 1;
 732       DECL_ARTIFICIAL (t) = 1;
 733       DECL_IGNORED_P (t) = 1;
 734       DECL_VISIBILITY_SPECIFIED (t) = 1;
 735       DECL_VISIBILITY (t) = VISIBILITY_HIDDEN;
 736
 737       stack_chk_fail_decl = t;
 738     }
 739
 740   return build_call_expr (t, 0);
 741 #endif
 742 }
 743
 744 bool
 745 hook_bool_const_rtx_commutative_p (const_rtx x,
 746                                    int outer_code ATTRIBUTE_UNUSED)
 747 {
 748   return COMMUTATIVE_P (x);
 749 }
 750
 751 rtx
 752 default_function_value (const_tree ret_type ATTRIBUTE_UNUSED,
 753                         const_tree fn_decl_or_type,
 754                         bool outgoing ATTRIBUTE_UNUSED)
 755 {
 756   /* The old interface doesn't handle receiving the function type.  */
 757   if (fn_decl_or_type
 758       && !DECL_P (fn_decl_or_type))
 759     fn_decl_or_type = NULL;
 760
 761 #ifdef FUNCTION_VALUE
 762   return FUNCTION_VALUE (ret_type, fn_decl_or_type);
 763 #else
 764   gcc_unreachable ();
 765 #endif
 766 }
 767
 768 rtx
 769 default_libcall_value (enum machine_mode mode ATTRIBUTE_UNUSED,
 770                        const_rtx fun ATTRIBUTE_UNUSED)
 771 {
 772 #ifdef LIBCALL_VALUE
 773   return LIBCALL_VALUE (mode);
 774 #else
 775   gcc_unreachable ();
 776 #endif
 777 }
 778
 779 /* The default hook for TARGET_FUNCTION_VALUE_REGNO_P.  */
 780
 781 bool
 782 default_function_value_regno_p (const unsigned int regno ATTRIBUTE_UNUSED)
 783 {
 784 #ifdef FUNCTION_VALUE_REGNO_P
 785   return FUNCTION_VALUE_REGNO_P (regno);
 786 #else
 787   gcc_unreachable ();
 788 #endif
 789 }
 790
 791 rtx
 792 default_internal_arg_pointer (void)
 793 {
 794   /* If the reg that the virtual arg pointer will be translated into is
 795      not a fixed reg or is the stack pointer, make a copy of the virtual
 796      arg pointer, and address parms via the copy.  The frame pointer is
 797      considered fixed even though it is not marked as such.  */
 798   if ((ARG_POINTER_REGNUM == STACK_POINTER_REGNUM
 799        || ! (fixed_regs[ARG_POINTER_REGNUM]
 800              || ARG_POINTER_REGNUM == FRAME_POINTER_REGNUM)))
 801     return copy_to_reg (virtual_incoming_args_rtx);
 802   else
 803     return virtual_incoming_args_rtx;
 804 }
 805
 806 rtx
 807 default_static_chain (const_tree fndecl, bool incoming_p)
 808 {
 809   if (!DECL_STATIC_CHAIN (fndecl))
 810     return NULL;
 811
 812   if (incoming_p)
 813     {
 814 #ifdef STATIC_CHAIN_INCOMING_REGNUM
 815       return gen_rtx_REG (Pmode, STATIC_CHAIN_INCOMING_REGNUM);
 816 #endif
 817     }
 818
 819 #ifdef STATIC_CHAIN_REGNUM
 820   return gen_rtx_REG (Pmode, STATIC_CHAIN_REGNUM);
 821 #endif
 822
 823   {
 824     static bool issued_error;
 825     if (!issued_error)
 826       {
 827         issued_error = true;
 828         sorry ("nested functions not supported on this target");
 829       }
 830
 831     /* It really doesn't matter what we return here, so long at it
 832        doesn't cause the rest of the compiler to crash.  */
 833     return gen_rtx_MEM (Pmode, stack_pointer_rtx);
 834   }
 835 }
 836
 837 void
 838 default_trampoline_init (rtx ARG_UNUSED (m_tramp), tree ARG_UNUSED (t_func),
 839                          rtx ARG_UNUSED (r_chain))
 840 {
 841   sorry ("nested function trampolines not supported on this target");
 842 }
 843
 844 int
 845 default_return_pops_args (tree fundecl ATTRIBUTE_UNUSED,
 846                           tree funtype ATTRIBUTE_UNUSED,
 847                           int size ATTRIBUTE_UNUSED)
 848 {
 849   return 0;
 850 }
 851
 852 reg_class_t
 853 default_branch_target_register_class (void)
 854 {
 855   return NO_REGS;
 856 }
 857
 858 #ifdef IRA_COVER_CLASSES
 859 const reg_class_t *
 860 default_ira_cover_classes (void)
 861 {
 862   static reg_class_t classes[] = IRA_COVER_CLASSES;
 863   return classes;
 864 }
 865 #endif
 866
 867 reg_class_t
 868 default_secondary_reload (bool in_p ATTRIBUTE_UNUSED, rtx x ATTRIBUTE_UNUSED,
 869                           reg_class_t reload_class_i ATTRIBUTE_UNUSED,
 870                           enum machine_mode reload_mode ATTRIBUTE_UNUSED,
 871                           secondary_reload_info *sri)
 872 {
 873   enum reg_class rclass = NO_REGS;
 874   enum reg_class reload_class = (enum reg_class) reload_class_i;
 875
 876   if (sri->prev_sri && sri->prev_sri->t_icode != CODE_FOR_nothing)
 877     {
 878       sri->icode = sri->prev_sri->t_icode;
 879       return NO_REGS;
 880     }
 881 #ifdef SECONDARY_INPUT_RELOAD_CLASS
 882   if (in_p)
 883     rclass = SECONDARY_INPUT_RELOAD_CLASS (reload_class, reload_mode, x);
 884 #endif
 885 #ifdef SECONDARY_OUTPUT_RELOAD_CLASS
 886   if (! in_p)
 887     rclass = SECONDARY_OUTPUT_RELOAD_CLASS (reload_class, reload_mode, x);
 888 #endif
 889   if (rclass != NO_REGS)
 890     {
 891       enum insn_code icode
 892         = direct_optab_handler (in_p ? reload_in_optab : reload_out_optab,
 893                                 reload_mode);
 894
 895       if (icode != CODE_FOR_nothing
 896           && !insn_operand_matches (icode, in_p, x))
 897         icode = CODE_FOR_nothing;
 898       else if (icode != CODE_FOR_nothing)
 899         {
 900           const char *insn_constraint, *scratch_constraint;
 901           char insn_letter, scratch_letter;
 902           enum reg_class insn_class, scratch_class;
 903
 904           gcc_assert (insn_data[(int) icode].n_operands == 3);
 905           insn_constraint = insn_data[(int) icode].operand[!in_p].constraint;
 906           if (!*insn_constraint)
 907             insn_class = ALL_REGS;
 908           else
 909             {
 910               if (in_p)
 911                 {
 912                   gcc_assert (*insn_constraint == '=');
 913                   insn_constraint++;
 914                 }
 915               insn_letter = *insn_constraint;
 916               insn_class
 917                 = (insn_letter == 'r' ? GENERAL_REGS
 918                    : REG_CLASS_FROM_CONSTRAINT ((unsigned char) insn_letter,
 919                                                 insn_constraint));
 920               gcc_assert (insn_class != NO_REGS);
 921             }
 922
 923           scratch_constraint = insn_data[(int) icode].operand[2].constraint;
 924           /* The scratch register's constraint must start with "=&",
 925              except for an input reload, where only "=" is necessary,
 926              and where it might be beneficial to re-use registers from
 927              the input.  */
 928           gcc_assert (scratch_constraint[0] == '='
 929                       && (in_p || scratch_constraint[1] == '&'));
 930           scratch_constraint++;
 931           if (*scratch_constraint == '&')
 932             scratch_constraint++;
 933           scratch_letter = *scratch_constraint;
 934           scratch_class
 935             = (scratch_letter == 'r' ? GENERAL_REGS
 936                : REG_CLASS_FROM_CONSTRAINT ((unsigned char) scratch_letter,
 937                                             scratch_constraint));
 938
 939           if (reg_class_subset_p (reload_class, insn_class))
 940             {
 941               gcc_assert (scratch_class == rclass);
 942               rclass = NO_REGS;
 943             }
 944           else
 945             rclass = insn_class;
 946
 947         }
 948       if (rclass == NO_REGS)
 949         sri->icode = icode;
 950       else
 951         sri->t_icode = icode;
 952     }
 953   return rclass;
 954 }
 955
 956 bool
 957 default_handle_c_option (size_t code ATTRIBUTE_UNUSED,
 958                          const char *arg ATTRIBUTE_UNUSED,
 959                          int value ATTRIBUTE_UNUSED)
 960 {
 961   return false;
 962 }
 963
 964 /* By default, if flag_pic is true, then neither local nor global relocs
 965    should be placed in readonly memory.  */
 966
 967 int
 968 default_reloc_rw_mask (void)
 969 {
 970   return flag_pic ? 3 : 0;
 971 }
 972
 973 /* By default, do no modification. */
 974 tree default_mangle_decl_assembler_name (tree decl ATTRIBUTE_UNUSED,
 975                                          tree id)
 976 {
 977    return id;
 978 }
 979
 980 bool
 981 default_builtin_vector_alignment_reachable (const_tree type, bool is_packed)
 982 {
 983   if (is_packed)
 984     return false;
 985
 986   /* Assuming that types whose size is > pointer-size are not guaranteed to be
 987      naturally aligned.  */
 988   if (tree_int_cst_compare (TYPE_SIZE (type), bitsize_int (POINTER_SIZE)) > 0)
 989     return false;
 990
 991   /* Assuming that types whose size is <= pointer-size
 992      are naturally aligned.  */
 993   return true;
 994 }
 995
 996 /* By default, assume that a target supports any factor of misalignment
 997    memory access if it supports movmisalign patten.
 998    is_packed is true if the memory access is defined in a packed struct.  */
 999 bool
1000 default_builtin_support_vector_misalignment (enum machine_mode mode,
1001                                              const_tree type
1002                                              ATTRIBUTE_UNUSED,
1003                                              int misalignment
1004                                              ATTRIBUTE_UNUSED,
1005                                              bool is_packed
1006                                              ATTRIBUTE_UNUSED)
1007 {
1008   if (optab_handler (movmisalign_optab, mode) != CODE_FOR_nothing)
1009     return true;
1010   return false;
1011 }
1012
1013 /* By default, only attempt to parallelize bitwise operations, and
1014    possibly adds/subtracts using bit-twiddling.  */
1015
1016 enum machine_mode
1017 default_preferred_simd_mode (enum machine_mode mode ATTRIBUTE_UNUSED)
1018 {
1019   return word_mode;
1020 }
1021
1022 /* By default only the size derived from the preferred vector mode
1023    is tried.  */
1024
1025 unsigned int
1026 default_autovectorize_vector_sizes (void)
1027 {
1028   return 0;
1029 }
1030
1031 /* Determine whether or not a pointer mode is valid. Assume defaults
1032    of ptr_mode or Pmode - can be overridden.  */
1033 bool
1034 default_valid_pointer_mode (enum machine_mode mode)
1035 {
1036   return (mode == ptr_mode || mode == Pmode);
1037 }
1038
1039 /* Determine whether the memory reference specified by REF may alias
1040    the C libraries errno location.  */
1041 bool
1042 default_ref_may_alias_errno (ao_ref *ref)
1043 {
1044   tree base = ao_ref_base (ref);
1045   /* The default implementation assumes the errno location is
1046      a declaration of type int or is always accessed via a
1047      pointer to int.  We assume that accesses to errno are
1048      not deliberately obfuscated (even in conforming ways).  */
1049   if (TYPE_UNSIGNED (TREE_TYPE (base))
1050       || TYPE_MODE (TREE_TYPE (base)) != TYPE_MODE (integer_type_node))
1051     return false;
1052   /* The default implementation assumes an errno location
1053      declaration is never defined in the current compilation unit.  */
1054   if (DECL_P (base)
1055       && !TREE_STATIC (base))
1056     return true;
1057   else if (TREE_CODE (base) == MEM_REF
1058            && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME)
1059     {
1060       struct ptr_info_def *pi = SSA_NAME_PTR_INFO (TREE_OPERAND (base, 0));
1061       return !pi || pi->pt.anything || pi->pt.nonlocal;
1062     }
1063   return false;
1064 }
1065
1066 /* Return the mode for a pointer to a given ADDRSPACE, defaulting to ptr_mode
1067    for the generic address space only.  */
1068
1069 enum machine_mode
1070 default_addr_space_pointer_mode (addr_space_t addrspace ATTRIBUTE_UNUSED)
1071 {
1072   gcc_assert (ADDR_SPACE_GENERIC_P (addrspace));
1073   return ptr_mode;
1074 }
1075
1076 /* Return the mode for an address in a given ADDRSPACE, defaulting to Pmode
1077    for the generic address space only.  */
1078
1079 enum machine_mode
1080 default_addr_space_address_mode (addr_space_t addrspace ATTRIBUTE_UNUSED)
1081 {
1082   gcc_assert (ADDR_SPACE_GENERIC_P (addrspace));
1083   return Pmode;
1084 }
1085
1086 /* Named address space version of valid_pointer_mode.  */
1087
1088 bool
1089 default_addr_space_valid_pointer_mode (enum machine_mode mode, addr_space_t as)
1090 {
1091   if (!ADDR_SPACE_GENERIC_P (as))
1092     return (mode == targetm.addr_space.pointer_mode (as)
1093             || mode == targetm.addr_space.address_mode (as));
1094
1095   return targetm.valid_pointer_mode (mode);
1096 }
1097
1098 /* Some places still assume that all pointer or address modes are the
1099    standard Pmode and ptr_mode.  These optimizations become invalid if
1100    the target actually supports multiple different modes.  For now,
1101    we disable such optimizations on such targets, using this function.  */
1102
1103 bool
1104 target_default_pointer_address_modes_p (void)
1105 {
1106   if (targetm.addr_space.address_mode != default_addr_space_address_mode)
1107     return false;
1108   if (targetm.addr_space.pointer_mode != default_addr_space_pointer_mode)
1109     return false;
1110
1111   return true;
1112 }
1113
1114 /* Named address space version of legitimate_address_p.  */
1115
1116 bool
1117 default_addr_space_legitimate_address_p (enum machine_mode mode, rtx mem,
1118                                          bool strict, addr_space_t as)
1119 {
1120   if (!ADDR_SPACE_GENERIC_P (as))
1121     gcc_unreachable ();
1122
1123   return targetm.legitimate_address_p (mode, mem, strict);
1124 }
1125
1126 /* Named address space version of LEGITIMIZE_ADDRESS.  */
1127
1128 rtx
1129 default_addr_space_legitimize_address (rtx x, rtx oldx,
1130                                        enum machine_mode mode, addr_space_t as)
1131 {
1132   if (!ADDR_SPACE_GENERIC_P (as))
1133     return x;
1134
1135   return targetm.legitimize_address (x, oldx, mode);
1136 }
1137
1138 /* The default hook for determining if one named address space is a subset of
1139    another and to return which address space to use as the common address
1140    space.  */
1141
1142 bool
1143 default_addr_space_subset_p (addr_space_t subset, addr_space_t superset)
1144 {
1145   return (subset == superset);
1146 }
1147
1148 /* The default hook for TARGET_ADDR_SPACE_CONVERT. This hook should never be
1149    called for targets with only a generic address space.  */
1150
1151 rtx
1152 default_addr_space_convert (rtx op ATTRIBUTE_UNUSED,
1153                             tree from_type ATTRIBUTE_UNUSED,
1154                             tree to_type ATTRIBUTE_UNUSED)
1155 {
1156   gcc_unreachable ();
1157 }
1158
1159 bool
1160 default_hard_regno_scratch_ok (unsigned int regno ATTRIBUTE_UNUSED)
1161 {
1162   return true;
1163 }
1164
1165 /* The default implementation of TARGET_MODE_DEPENDENT_ADDRESS_P.  */
1166
1167 bool
1168 default_mode_dependent_address_p (const_rtx addr ATTRIBUTE_UNUSED)
1169 {
1170 #ifdef GO_IF_MODE_DEPENDENT_ADDRESS
1171
1172   GO_IF_MODE_DEPENDENT_ADDRESS (CONST_CAST_RTX (addr), win);
1173   return false;
1174   /* Label `win' might (not) be used via GO_IF_MODE_DEPENDENT_ADDRESS.  */
1175  win: ATTRIBUTE_UNUSED_LABEL
1176   return true;
1177
1178 #else
1179
1180   return false;
1181
1182 #endif
1183 }
1184
1185 bool
1186 default_target_option_valid_attribute_p (tree ARG_UNUSED (fndecl),
1187                                          tree ARG_UNUSED (name),
1188                                          tree ARG_UNUSED (args),
1189                                          int ARG_UNUSED (flags))
1190 {
1191   warning (OPT_Wattributes,
1192            "target attribute is not supported on this machine");
1193
1194   return false;
1195 }
1196
1197 bool
1198 default_target_option_pragma_parse (tree ARG_UNUSED (args),
1199                                     tree ARG_UNUSED (pop_target))
1200 {
1201   warning (OPT_Wpragmas,
1202            "#pragma GCC target is not supported for this machine");
1203
1204   return false;
1205 }
1206
1207 bool
1208 default_target_can_inline_p (tree caller, tree callee)
1209 {
1210   bool ret = false;
1211   tree callee_opts = DECL_FUNCTION_SPECIFIC_TARGET (callee);
1212   tree caller_opts = DECL_FUNCTION_SPECIFIC_TARGET (caller);
1213
1214   /* If callee has no option attributes, then it is ok to inline */
1215   if (!callee_opts)
1216     ret = true;
1217
1218   /* If caller has no option attributes, but callee does then it is not ok to
1219      inline */
1220   else if (!caller_opts)
1221     ret = false;
1222
1223   /* If both caller and callee have attributes, assume that if the pointer is
1224      different, the the two functions have different target options since
1225      build_target_option_node uses a hash table for the options.  */
1226   else
1227     ret = (callee_opts == caller_opts);
1228
1229   return ret;
1230 }
1231
1232 #ifndef HAVE_casesi
1233 # define HAVE_casesi 0
1234 #endif
1235
1236 /* If the machine does not have a case insn that compares the bounds,
1237    this means extra overhead for dispatch tables, which raises the
1238    threshold for using them.  */
1239
1240 unsigned int default_case_values_threshold (void)
1241 {
1242   return (HAVE_casesi ? 4 : 5);
1243 }
1244
1245 bool
1246 default_have_conditional_execution (void)
1247 {
1248 #ifdef HAVE_conditional_execution
1249   return HAVE_conditional_execution;
1250 #else
1251   return false;
1252 #endif
1253 }
1254
1255 /* Compute cost of moving registers to/from memory.  */
1256
1257 int
1258 default_memory_move_cost (enum machine_mode mode ATTRIBUTE_UNUSED,
1259                           reg_class_t rclass ATTRIBUTE_UNUSED,
1260                           bool in ATTRIBUTE_UNUSED)
1261 {
1262 #ifndef MEMORY_MOVE_COST
1263     return (4 + memory_move_secondary_cost (mode, (enum reg_class) rclass, in));
1264 #else
1265     return MEMORY_MOVE_COST (mode, (enum reg_class) rclass, in);
1266 #endif
1267 }
1268
1269 /* Compute cost of moving data from a register of class FROM to one of
1270    TO, using MODE.  */
1271
1272 int
1273 default_register_move_cost (enum machine_mode mode ATTRIBUTE_UNUSED,
1274                             reg_class_t from ATTRIBUTE_UNUSED,
1275                             reg_class_t to ATTRIBUTE_UNUSED)
1276 {
1277 #ifndef REGISTER_MOVE_COST
1278   return 2;
1279 #else
1280   return REGISTER_MOVE_COST (mode, (enum reg_class) from, (enum reg_class) to);
1281 #endif
1282 }
1283
1284 bool
1285 default_profile_before_prologue (void)
1286 {
1287 #ifdef PROFILE_BEFORE_PROLOGUE
1288   return true;
1289 #else
1290   return false;
1291 #endif
1292 }
1293
1294 /* The default implementation of TARGET_PREFERRED_RELOAD_CLASS.  */
1295
1296 reg_class_t
1297 default_preferred_reload_class (rtx x ATTRIBUTE_UNUSED,
1298                                 reg_class_t rclass)
1299 {
1300 #ifdef PREFERRED_RELOAD_CLASS
1301   return (reg_class_t) PREFERRED_RELOAD_CLASS (x, (enum reg_class) rclass);
1302 #else
1303   return rclass;
1304 #endif
1305 }
1306
1307 /* The default implementation of TARGET_OUTPUT_PREFERRED_RELOAD_CLASS.  */
1308
1309 reg_class_t
1310 default_preferred_output_reload_class (rtx x ATTRIBUTE_UNUSED,
1311                                        reg_class_t rclass)
1312 {
1313 #ifdef PREFERRED_OUTPUT_RELOAD_CLASS
1314   return PREFERRED_OUTPUT_RELOAD_CLASS (x, (enum reg_class) rclass);
1315 #else
1316   return rclass;
1317 #endif
1318 }
1319
1320 /* The default implementation of TARGET_PREFERRED_RENAME_CLASS.  */
1321 reg_class_t
1322 default_preferred_rename_class (reg_class_t rclass ATTRIBUTE_UNUSED)
1323 {
1324   return NO_REGS;
1325 }
1326
1327 /* The default implementation of TARGET_CLASS_LIKELY_SPILLED_P.  */
1328
1329 bool
1330 default_class_likely_spilled_p (reg_class_t rclass)
1331 {
1332   return (reg_class_size[(int) rclass] == 1);
1333 }
1334
1335 /* Determine the debugging unwind mechanism for the target.  */
1336
1337 enum unwind_info_type
1338 default_debug_unwind_info (void)
1339 {
1340   /* If the target wants to force the use of dwarf2 unwind info, let it.  */
1341   /* ??? Change all users to the hook, then poison this.  */
1342 #ifdef DWARF2_FRAME_INFO
1343   if (DWARF2_FRAME_INFO)
1344     return UI_DWARF2;
1345 #endif
1346
1347   /* Otherwise, only turn it on if dwarf2 debugging is enabled.  */
1348 #ifdef DWARF2_DEBUGGING_INFO
1349   if (write_symbols == DWARF2_DEBUG || write_symbols == VMS_AND_DWARF2_DEBUG)
1350     return UI_DWARF2;
1351 #endif
1352
1353   return UI_NONE;
1354 }
1355
1356 /* Determine the exception handling mechanism for the target.  */
1357
1358 enum unwind_info_type
1359 default_except_unwind_info (struct gcc_options *opts ATTRIBUTE_UNUSED)
1360 {
1361   /* Obey the configure switch to turn on sjlj exceptions.  */
1362 #ifdef CONFIG_SJLJ_EXCEPTIONS
1363   if (CONFIG_SJLJ_EXCEPTIONS)
1364     return UI_SJLJ;
1365 #endif
1366
1367   /* ??? Change all users to the hook, then poison this.  */
1368 #ifdef DWARF2_UNWIND_INFO
1369   if (DWARF2_UNWIND_INFO)
1370     return UI_DWARF2;
1371 #endif
1372
1373   return UI_SJLJ;
1374 }
1375
1376 /* To be used by targets that force dwarf2 unwind enabled.  */
1377
1378 enum unwind_info_type
1379 dwarf2_except_unwind_info (struct gcc_options *opts ATTRIBUTE_UNUSED)
1380 {
1381   /* Obey the configure switch to turn on sjlj exceptions.  */
1382 #ifdef CONFIG_SJLJ_EXCEPTIONS
1383   if (CONFIG_SJLJ_EXCEPTIONS)
1384     return UI_SJLJ;
1385 #endif
1386
1387   return UI_DWARF2;
1388 }
1389
1390 /* To be used by targets that force sjlj unwind enabled.  */
1391
1392 enum unwind_info_type
1393 sjlj_except_unwind_info (struct gcc_options *opts ATTRIBUTE_UNUSED)
1394 {
1395   return UI_SJLJ;
1396 }
1397
1398 /* To be used by targets where reg_raw_mode doesn't return the right
1399    mode for registers used in apply_builtin_return and apply_builtin_arg.  */
1400
1401 enum machine_mode
1402 default_get_reg_raw_mode(int regno)
1403 {
1404   return reg_raw_mode[regno];
1405 }
1406
1407 /* Return true if the state of option OPTION should be stored in PCH files
1408    and checked by default_pch_valid_p.  Store the option's current state
1409    in STATE if so.  */
1410
1411 static inline bool
1412 option_affects_pch_p (int option, struct cl_option_state *state)
1413 {
1414   if ((cl_options[option].flags & CL_TARGET) == 0)
1415     return false;
1416   if (option_flag_var (option, &global_options) == &target_flags)
1417     if (targetm.check_pch_target_flags)
1418       return false;
1419   return get_option_state (&global_options, option, state);
1420 }
1421
1422 /* Default version of get_pch_validity.
1423    By default, every flag difference is fatal; that will be mostly right for
1424    most targets, but completely right for very few.  */
1425
1426 void *
1427 default_get_pch_validity (size_t *sz)
1428 {
1429   struct cl_option_state state;
1430   size_t i;
1431   char *result, *r;
1432
1433   *sz = 2;
1434   if (targetm.check_pch_target_flags)
1435     *sz += sizeof (target_flags);
1436   for (i = 0; i < cl_options_count; i++)
1437     if (option_affects_pch_p (i, &state))
1438       *sz += state.size;
1439
1440   result = r = XNEWVEC (char, *sz);
1441   r[0] = flag_pic;
1442   r[1] = flag_pie;
1443   r += 2;
1444   if (targetm.check_pch_target_flags)
1445     {
1446       memcpy (r, &target_flags, sizeof (target_flags));
1447       r += sizeof (target_flags);
1448     }
1449
1450   for (i = 0; i < cl_options_count; i++)
1451     if (option_affects_pch_p (i, &state))
1452       {
1453         memcpy (r, state.data, state.size);
1454         r += state.size;
1455       }
1456
1457   return result;
1458 }
1459
1460 /* Return a message which says that a PCH file was created with a different
1461    setting of OPTION.  */
1462
1463 static const char *
1464 pch_option_mismatch (const char *option)
1465 {
1466   char *r;
1467
1468   asprintf (&r, _("created and used with differing settings of '%s'"), option);
1469   if (r == NULL)
1470     return _("out of memory");
1471   return r;
1472 }
1473
1474 /* Default version of pch_valid_p.  */
1475
1476 const char *
1477 default_pch_valid_p (const void *data_p, size_t len)
1478 {
1479   struct cl_option_state state;
1480   const char *data = (const char *)data_p;
1481   size_t i;
1482
1483   /* -fpic and -fpie also usually make a PCH invalid.  */
1484   if (data[0] != flag_pic)
1485     return _("created and used with different settings of -fpic");
1486   if (data[1] != flag_pie)
1487     return _("created and used with different settings of -fpie");
1488   data += 2;
1489
1490   /* Check target_flags.  */
1491   if (targetm.check_pch_target_flags)
1492     {
1493       int tf;
1494       const char *r;
1495
1496       memcpy (&tf, data, sizeof (target_flags));
1497       data += sizeof (target_flags);
1498       len -= sizeof (target_flags);
1499       r = targetm.check_pch_target_flags (tf);
1500       if (r != NULL)
1501         return r;
1502     }
1503
1504   for (i = 0; i < cl_options_count; i++)
1505     if (option_affects_pch_p (i, &state))
1506       {
1507         if (memcmp (data, state.data, state.size) != 0)
1508           return pch_option_mismatch (cl_options[i].opt_text);
1509         data += state.size;
1510         len -= state.size;
1511       }
1512
1513   return NULL;
1514 }
1515
1516 /* Default version of TARGET_HANDLE_OPTION.  */
1517
1518 bool
1519 default_target_handle_option (struct gcc_options *opts ATTRIBUTE_UNUSED,
1520                               struct gcc_options *opts_set ATTRIBUTE_UNUSED,
1521                               const struct cl_decoded_option *decoded ATTRIBUTE_UNUSED,
1522                               location_t loc ATTRIBUTE_UNUSED)
1523 {
1524   return true;
1525 }
1526
1527 const struct default_options empty_optimization_table[] =
1528   {
1529     { OPT_LEVELS_NONE, 0, NULL, 0 }
1530   };
1531
1532 #include "gt-targhooks.h"