gcc/targhooks.c

   1 /* Default target hook functions.
   2    Copyright (C) 2003, 2004, 2005, 2007, 2008, 2009
   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 "toplev.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 "reload.h"
  67 #include "optabs.h"
  68 #include "recog.h"
  69
  70
  71 void
  72 default_external_libcall (rtx fun ATTRIBUTE_UNUSED)
  73 {
  74 #ifdef ASM_OUTPUT_EXTERNAL_LIBCALL
  75   ASM_OUTPUT_EXTERNAL_LIBCALL(asm_out_file, fun);
  76 #endif
  77 }
  78
  79 int
  80 default_unspec_may_trap_p (const_rtx x, unsigned flags)
  81 {
  82   int i;
  83
  84   if (GET_CODE (x) == UNSPEC_VOLATILE
  85       /* Any floating arithmetic may trap.  */
  86       || (SCALAR_FLOAT_MODE_P (GET_MODE (x))
  87           && flag_trapping_math))
  88     return 1;
  89
  90   for (i = 0; i < XVECLEN (x, 0); ++i)
  91     {
  92       if (may_trap_p_1 (XVECEXP (x, 0, i), flags))
  93         return 1;
  94     }
  95
  96   return 0;
  97 }
  98
  99 enum machine_mode
 100 default_cc_modes_compatible (enum machine_mode m1, enum machine_mode m2)
 101 {
 102   if (m1 == m2)
 103     return m1;
 104   return VOIDmode;
 105 }
 106
 107 bool
 108 default_return_in_memory (const_tree type,
 109                           const_tree fntype ATTRIBUTE_UNUSED)
 110 {
 111   return (TYPE_MODE (type) == BLKmode);
 112 }
 113
 114 rtx
 115 default_expand_builtin_saveregs (void)
 116 {
 117   error ("__builtin_saveregs not supported by this target");
 118   return const0_rtx;
 119 }
 120
 121 void
 122 default_setup_incoming_varargs (CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
 123                                 enum machine_mode mode ATTRIBUTE_UNUSED,
 124                                 tree type ATTRIBUTE_UNUSED,
 125                                 int *pretend_arg_size ATTRIBUTE_UNUSED,
 126                                 int second_time ATTRIBUTE_UNUSED)
 127 {
 128 }
 129
 130 /* The default implementation of TARGET_BUILTIN_SETJMP_FRAME_VALUE.  */
 131
 132 rtx
 133 default_builtin_setjmp_frame_value (void)
 134 {
 135   return virtual_stack_vars_rtx;
 136 }
 137
 138 /* Generic hook that takes a CUMULATIVE_ARGS pointer and returns false.  */
 139
 140 bool
 141 hook_bool_CUMULATIVE_ARGS_false (CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED)
 142 {
 143   return false;
 144 }
 145
 146 bool
 147 default_pretend_outgoing_varargs_named (CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED)
 148 {
 149   return (targetm.calls.setup_incoming_varargs
 150           != default_setup_incoming_varargs);
 151 }
 152
 153 enum machine_mode
 154 default_eh_return_filter_mode (void)
 155 {
 156   return targetm.unwind_word_mode ();
 157 }
 158
 159 enum machine_mode
 160 default_libgcc_cmp_return_mode (void)
 161 {
 162   return word_mode;
 163 }
 164
 165 enum machine_mode
 166 default_libgcc_shift_count_mode (void)
 167 {
 168   return word_mode;
 169 }
 170
 171 enum machine_mode
 172 default_unwind_word_mode (void)
 173 {
 174   return word_mode;
 175 }
 176
 177 /* The default implementation of TARGET_SHIFT_TRUNCATION_MASK.  */
 178
 179 unsigned HOST_WIDE_INT
 180 default_shift_truncation_mask (enum machine_mode mode)
 181 {
 182   return SHIFT_COUNT_TRUNCATED ? GET_MODE_BITSIZE (mode) - 1 : 0;
 183 }
 184
 185 /* The default implementation of TARGET_MIN_DIVISIONS_FOR_RECIP_MUL.  */
 186
 187 unsigned int
 188 default_min_divisions_for_recip_mul (enum machine_mode mode ATTRIBUTE_UNUSED)
 189 {
 190   return have_insn_for (DIV, mode) ? 3 : 2;
 191 }
 192
 193 /* The default implementation of TARGET_MODE_REP_EXTENDED.  */
 194
 195 int
 196 default_mode_rep_extended (enum machine_mode mode ATTRIBUTE_UNUSED,
 197                            enum machine_mode mode_rep ATTRIBUTE_UNUSED)
 198 {
 199   return UNKNOWN;
 200 }
 201
 202 /* Generic hook that takes a CUMULATIVE_ARGS pointer and returns true.  */
 203
 204 bool
 205 hook_bool_CUMULATIVE_ARGS_true (CUMULATIVE_ARGS * a ATTRIBUTE_UNUSED)
 206 {
 207   return true;
 208 }
 209
 210 /* Return machine mode for non-standard suffix
 211    or VOIDmode if non-standard suffixes are unsupported.  */
 212 enum machine_mode
 213 default_mode_for_suffix (char suffix ATTRIBUTE_UNUSED)
 214 {
 215   return VOIDmode;
 216 }
 217
 218 /* The generic C++ ABI specifies this is a 64-bit value.  */
 219 tree
 220 default_cxx_guard_type (void)
 221 {
 222   return long_long_integer_type_node;
 223 }
 224
 225
 226 /* Returns the size of the cookie to use when allocating an array
 227    whose elements have the indicated TYPE.  Assumes that it is already
 228    known that a cookie is needed.  */
 229
 230 tree
 231 default_cxx_get_cookie_size (tree type)
 232 {
 233   tree cookie_size;
 234
 235   /* We need to allocate an additional max (sizeof (size_t), alignof
 236      (true_type)) bytes.  */
 237   tree sizetype_size;
 238   tree type_align;
 239
 240   sizetype_size = size_in_bytes (sizetype);
 241   type_align = size_int (TYPE_ALIGN_UNIT (type));
 242   if (INT_CST_LT_UNSIGNED (type_align, sizetype_size))
 243     cookie_size = sizetype_size;
 244   else
 245     cookie_size = type_align;
 246
 247   return cookie_size;
 248 }
 249
 250 /* Return true if a parameter must be passed by reference.  This version
 251    of the TARGET_PASS_BY_REFERENCE hook uses just MUST_PASS_IN_STACK.  */
 252
 253 bool
 254 hook_pass_by_reference_must_pass_in_stack (CUMULATIVE_ARGS *c ATTRIBUTE_UNUSED,
 255         enum machine_mode mode ATTRIBUTE_UNUSED, const_tree type ATTRIBUTE_UNUSED,
 256         bool named_arg ATTRIBUTE_UNUSED)
 257 {
 258   return targetm.calls.must_pass_in_stack (mode, type);
 259 }
 260
 261 /* Return true if a parameter follows callee copies conventions.  This
 262    version of the hook is true for all named arguments.  */
 263
 264 bool
 265 hook_callee_copies_named (CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
 266                           enum machine_mode mode ATTRIBUTE_UNUSED,
 267                           const_tree type ATTRIBUTE_UNUSED, bool named)
 268 {
 269   return named;
 270 }
 271
 272 /* Emit any directives required to unwind this instruction.  */
 273
 274 void
 275 default_unwind_emit (FILE * stream ATTRIBUTE_UNUSED,
 276                      rtx insn ATTRIBUTE_UNUSED)
 277 {
 278   /* Should never happen.  */
 279   gcc_unreachable ();
 280 }
 281
 282 /* True if MODE is valid for the target.  By "valid", we mean able to
 283    be manipulated in non-trivial ways.  In particular, this means all
 284    the arithmetic is supported.
 285
 286    By default we guess this means that any C type is supported.  If
 287    we can't map the mode back to a type that would be available in C,
 288    then reject it.  Special case, here, is the double-word arithmetic
 289    supported by optabs.c.  */
 290
 291 bool
 292 default_scalar_mode_supported_p (enum machine_mode mode)
 293 {
 294   int precision = GET_MODE_PRECISION (mode);
 295
 296   switch (GET_MODE_CLASS (mode))
 297     {
 298     case MODE_PARTIAL_INT:
 299     case MODE_INT:
 300       if (precision == CHAR_TYPE_SIZE)
 301         return true;
 302       if (precision == SHORT_TYPE_SIZE)
 303         return true;
 304       if (precision == INT_TYPE_SIZE)
 305         return true;
 306       if (precision == LONG_TYPE_SIZE)
 307         return true;
 308       if (precision == LONG_LONG_TYPE_SIZE)
 309         return true;
 310       if (precision == 2 * BITS_PER_WORD)
 311         return true;
 312       return false;
 313
 314     case MODE_FLOAT:
 315       if (precision == FLOAT_TYPE_SIZE)
 316         return true;
 317       if (precision == DOUBLE_TYPE_SIZE)
 318         return true;
 319       if (precision == LONG_DOUBLE_TYPE_SIZE)
 320         return true;
 321       return false;
 322
 323     case MODE_DECIMAL_FLOAT:
 324     case MODE_FRACT:
 325     case MODE_UFRACT:
 326     case MODE_ACCUM:
 327     case MODE_UACCUM:
 328       return false;
 329
 330     default:
 331       gcc_unreachable ();
 332     }
 333 }
 334
 335 /* True if the target supports decimal floating point.  */
 336
 337 bool
 338 default_decimal_float_supported_p (void)
 339 {
 340   return ENABLE_DECIMAL_FLOAT;
 341 }
 342
 343 /* True if the target supports fixed-point arithmetic.  */
 344
 345 bool
 346 default_fixed_point_supported_p (void)
 347 {
 348   return ENABLE_FIXED_POINT;
 349 }
 350
 351 /* NULL if INSN insn is valid within a low-overhead loop, otherwise returns
 352    an error message.
 353
 354    This function checks whether a given INSN is valid within a low-overhead
 355    loop.  If INSN is invalid it returns the reason for that, otherwise it
 356    returns NULL. A called function may clobber any special registers required
 357    for low-overhead looping. Additionally, some targets (eg, PPC) use the count
 358    register for branch on table instructions. We reject the doloop pattern in
 359    these cases.  */
 360
 361 const char *
 362 default_invalid_within_doloop (const_rtx insn)
 363 {
 364   if (CALL_P (insn))
 365     return "Function call in loop.";
 366
 367   if (JUMP_P (insn)
 368       && (GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC
 369           || GET_CODE (PATTERN (insn)) == ADDR_VEC))
 370     return "Computed branch in the loop.";
 371
 372   return NULL;
 373 }
 374
 375 /* Mapping of builtin functions to vectorized variants.  */
 376
 377 tree
 378 default_builtin_vectorized_function (enum built_in_function fn ATTRIBUTE_UNUSED,
 379                                      tree type_out ATTRIBUTE_UNUSED,
 380                                      tree type_in ATTRIBUTE_UNUSED)
 381 {
 382   return NULL_TREE;
 383 }
 384
 385 /* Vectorized conversion.  */
 386
 387 tree
 388 default_builtin_vectorized_conversion (enum tree_code code ATTRIBUTE_UNUSED,
 389                                        tree type ATTRIBUTE_UNUSED)
 390 {
 391   return NULL_TREE;
 392 }
 393
 394 /* Reciprocal.  */
 395
 396 tree
 397 default_builtin_reciprocal (enum built_in_function fn ATTRIBUTE_UNUSED,
 398                             bool md_fn ATTRIBUTE_UNUSED,
 399                             bool sqrt ATTRIBUTE_UNUSED)
 400 {
 401   return NULL_TREE;
 402 }
 403
 404 bool
 405 hook_bool_CUMULATIVE_ARGS_mode_tree_bool_false (
 406         CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
 407         enum machine_mode mode ATTRIBUTE_UNUSED,
 408         const_tree type ATTRIBUTE_UNUSED, bool named ATTRIBUTE_UNUSED)
 409 {
 410   return false;
 411 }
 412
 413 bool
 414 hook_bool_CUMULATIVE_ARGS_mode_tree_bool_true (
 415         CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
 416         enum machine_mode mode ATTRIBUTE_UNUSED,
 417         const_tree type ATTRIBUTE_UNUSED, bool named ATTRIBUTE_UNUSED)
 418 {
 419   return true;
 420 }
 421
 422 int
 423 hook_int_CUMULATIVE_ARGS_mode_tree_bool_0 (
 424         CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
 425         enum machine_mode mode ATTRIBUTE_UNUSED,
 426         tree type ATTRIBUTE_UNUSED, bool named ATTRIBUTE_UNUSED)
 427 {
 428   return 0;
 429 }
 430
 431 void
 432 hook_void_bitmap (bitmap regs ATTRIBUTE_UNUSED)
 433 {
 434 }
 435
 436 const char *
 437 hook_invalid_arg_for_unprototyped_fn (
 438         const_tree typelist ATTRIBUTE_UNUSED,
 439         const_tree funcdecl ATTRIBUTE_UNUSED,
 440         const_tree val ATTRIBUTE_UNUSED)
 441 {
 442   return NULL;
 443 }
 444
 445 /* Initialize the stack protection decls.  */
 446
 447 /* Stack protection related decls living in libgcc.  */
 448 static GTY(()) tree stack_chk_guard_decl;
 449
 450 tree
 451 default_stack_protect_guard (void)
 452 {
 453   tree t = stack_chk_guard_decl;
 454
 455   if (t == NULL)
 456     {
 457       t = build_decl (VAR_DECL, get_identifier ("__stack_chk_guard"),
 458                       ptr_type_node);
 459       TREE_STATIC (t) = 1;
 460       TREE_PUBLIC (t) = 1;
 461       DECL_EXTERNAL (t) = 1;
 462       TREE_USED (t) = 1;
 463       TREE_THIS_VOLATILE (t) = 1;
 464       DECL_ARTIFICIAL (t) = 1;
 465       DECL_IGNORED_P (t) = 1;
 466
 467       stack_chk_guard_decl = t;
 468     }
 469
 470   return t;
 471 }
 472
 473 static GTY(()) tree stack_chk_fail_decl;
 474
 475 tree
 476 default_external_stack_protect_fail (void)
 477 {
 478   tree t = stack_chk_fail_decl;
 479
 480   if (t == NULL_TREE)
 481     {
 482       t = build_function_type_list (void_type_node, NULL_TREE);
 483       t = build_decl (FUNCTION_DECL, get_identifier ("__stack_chk_fail"), t);
 484       TREE_STATIC (t) = 1;
 485       TREE_PUBLIC (t) = 1;
 486       DECL_EXTERNAL (t) = 1;
 487       TREE_USED (t) = 1;
 488       TREE_THIS_VOLATILE (t) = 1;
 489       TREE_NOTHROW (t) = 1;
 490       DECL_ARTIFICIAL (t) = 1;
 491       DECL_IGNORED_P (t) = 1;
 492       DECL_VISIBILITY (t) = VISIBILITY_DEFAULT;
 493       DECL_VISIBILITY_SPECIFIED (t) = 1;
 494
 495       stack_chk_fail_decl = t;
 496     }
 497
 498   return build_call_expr (t, 0);
 499 }
 500
 501 tree
 502 default_hidden_stack_protect_fail (void)
 503 {
 504 #ifndef HAVE_GAS_HIDDEN
 505   return default_external_stack_protect_fail ();
 506 #else
 507   tree t = stack_chk_fail_decl;
 508
 509   if (!flag_pic)
 510     return default_external_stack_protect_fail ();
 511
 512   if (t == NULL_TREE)
 513     {
 514       t = build_function_type_list (void_type_node, NULL_TREE);
 515       t = build_decl (FUNCTION_DECL,
 516                       get_identifier ("__stack_chk_fail_local"), t);
 517       TREE_STATIC (t) = 1;
 518       TREE_PUBLIC (t) = 1;
 519       DECL_EXTERNAL (t) = 1;
 520       TREE_USED (t) = 1;
 521       TREE_THIS_VOLATILE (t) = 1;
 522       TREE_NOTHROW (t) = 1;
 523       DECL_ARTIFICIAL (t) = 1;
 524       DECL_IGNORED_P (t) = 1;
 525       DECL_VISIBILITY_SPECIFIED (t) = 1;
 526       DECL_VISIBILITY (t) = VISIBILITY_HIDDEN;
 527
 528       stack_chk_fail_decl = t;
 529     }
 530
 531   return build_call_expr (t, 0);
 532 #endif
 533 }
 534
 535 bool
 536 hook_bool_const_rtx_commutative_p (const_rtx x,
 537                                    int outer_code ATTRIBUTE_UNUSED)
 538 {
 539   return COMMUTATIVE_P (x);
 540 }
 541
 542 rtx
 543 default_function_value (const_tree ret_type ATTRIBUTE_UNUSED,
 544                         const_tree fn_decl_or_type,
 545                         bool outgoing ATTRIBUTE_UNUSED)
 546 {
 547   /* The old interface doesn't handle receiving the function type.  */
 548   if (fn_decl_or_type
 549       && !DECL_P (fn_decl_or_type))
 550     fn_decl_or_type = NULL;
 551
 552 #ifdef FUNCTION_OUTGOING_VALUE
 553   if (outgoing)
 554     return FUNCTION_OUTGOING_VALUE (ret_type, fn_decl_or_type);
 555 #endif
 556
 557 #ifdef FUNCTION_VALUE
 558   return FUNCTION_VALUE (ret_type, fn_decl_or_type);
 559 #else
 560   return NULL_RTX;
 561 #endif
 562 }
 563
 564 rtx
 565 default_internal_arg_pointer (void)
 566 {
 567   /* If the reg that the virtual arg pointer will be translated into is
 568      not a fixed reg or is the stack pointer, make a copy of the virtual
 569      arg pointer, and address parms via the copy.  The frame pointer is
 570      considered fixed even though it is not marked as such.  */
 571   if ((ARG_POINTER_REGNUM == STACK_POINTER_REGNUM
 572        || ! (fixed_regs[ARG_POINTER_REGNUM]
 573              || ARG_POINTER_REGNUM == FRAME_POINTER_REGNUM)))
 574     return copy_to_reg (virtual_incoming_args_rtx);
 575   else
 576     return virtual_incoming_args_rtx;
 577 }
 578
 579 enum reg_class
 580 default_branch_target_register_class (void)
 581 {
 582   return NO_REGS;
 583 }
 584
 585 #ifdef IRA_COVER_CLASSES
 586 const enum reg_class *
 587 default_ira_cover_classes (void)
 588 {
 589   static enum reg_class classes[] = IRA_COVER_CLASSES;
 590   return classes;
 591 }
 592 #endif
 593
 594 enum reg_class
 595 default_secondary_reload (bool in_p ATTRIBUTE_UNUSED, rtx x ATTRIBUTE_UNUSED,
 596                           enum reg_class reload_class ATTRIBUTE_UNUSED,
 597                           enum machine_mode reload_mode ATTRIBUTE_UNUSED,
 598                           secondary_reload_info *sri)
 599 {
 600   enum reg_class rclass = NO_REGS;
 601
 602   if (sri->prev_sri && sri->prev_sri->t_icode != CODE_FOR_nothing)
 603     {
 604       sri->icode = sri->prev_sri->t_icode;
 605       return NO_REGS;
 606     }
 607 #ifdef SECONDARY_INPUT_RELOAD_CLASS
 608   if (in_p)
 609     rclass = SECONDARY_INPUT_RELOAD_CLASS (reload_class, reload_mode, x);
 610 #endif
 611 #ifdef SECONDARY_OUTPUT_RELOAD_CLASS
 612   if (! in_p)
 613     rclass = SECONDARY_OUTPUT_RELOAD_CLASS (reload_class, reload_mode, x);
 614 #endif
 615   if (rclass != NO_REGS)
 616     {
 617       enum insn_code icode = (in_p ? reload_in_optab[(int) reload_mode]
 618                               : reload_out_optab[(int) reload_mode]);
 619
 620       if (icode != CODE_FOR_nothing
 621           && insn_data[(int) icode].operand[in_p].predicate
 622           && ! insn_data[(int) icode].operand[in_p].predicate (x, reload_mode))
 623         icode = CODE_FOR_nothing;
 624       else if (icode != CODE_FOR_nothing)
 625         {
 626           const char *insn_constraint, *scratch_constraint;
 627           char insn_letter, scratch_letter;
 628           enum reg_class insn_class, scratch_class;
 629
 630           gcc_assert (insn_data[(int) icode].n_operands == 3);
 631           insn_constraint = insn_data[(int) icode].operand[!in_p].constraint;
 632           if (!*insn_constraint)
 633             insn_class = ALL_REGS;
 634           else
 635             {
 636               if (in_p)
 637                 {
 638                   gcc_assert (*insn_constraint == '=');
 639                   insn_constraint++;
 640                 }
 641               insn_letter = *insn_constraint;
 642               insn_class
 643                 = (insn_letter == 'r' ? GENERAL_REGS
 644                    : REG_CLASS_FROM_CONSTRAINT ((unsigned char) insn_letter,
 645                                                 insn_constraint));
 646               gcc_assert (insn_class != NO_REGS);
 647             }
 648
 649           scratch_constraint = insn_data[(int) icode].operand[2].constraint;
 650           /* The scratch register's constraint must start with "=&",
 651              except for an input reload, where only "=" is necessary,
 652              and where it might be beneficial to re-use registers from
 653              the input.  */
 654           gcc_assert (scratch_constraint[0] == '='
 655                       && (in_p || scratch_constraint[1] == '&'));
 656           scratch_constraint++;
 657           if (*scratch_constraint == '&')
 658             scratch_constraint++;
 659           scratch_letter = *scratch_constraint;
 660           scratch_class
 661             = (scratch_letter == 'r' ? GENERAL_REGS
 662                : REG_CLASS_FROM_CONSTRAINT ((unsigned char) scratch_letter,
 663                                             scratch_constraint));
 664
 665           if (reg_class_subset_p (reload_class, insn_class))
 666             {
 667               gcc_assert (scratch_class == rclass);
 668               rclass = NO_REGS;
 669             }
 670           else
 671             rclass = insn_class;
 672
 673         }
 674       if (rclass == NO_REGS)
 675         sri->icode = icode;
 676       else
 677         sri->t_icode = icode;
 678     }
 679   return rclass;
 680 }
 681
 682 bool
 683 default_handle_c_option (size_t code ATTRIBUTE_UNUSED,
 684                          const char *arg ATTRIBUTE_UNUSED,
 685                          int value ATTRIBUTE_UNUSED)
 686 {
 687   return false;
 688 }
 689
 690 /* By default, if flag_pic is true, then neither local nor global relocs
 691    should be placed in readonly memory.  */
 692
 693 int
 694 default_reloc_rw_mask (void)
 695 {
 696   return flag_pic ? 3 : 0;
 697 }
 698
 699 /* By default, do no modification. */
 700 tree default_mangle_decl_assembler_name (tree decl ATTRIBUTE_UNUSED,
 701                                          tree id)
 702 {
 703    return id;
 704 }
 705
 706 bool
 707 default_builtin_vector_alignment_reachable (const_tree type, bool is_packed)
 708 {
 709   if (is_packed)
 710     return false;
 711
 712   /* Assuming that types whose size is > pointer-size are not guaranteed to be
 713      naturally aligned.  */
 714   if (tree_int_cst_compare (TYPE_SIZE (type), bitsize_int (POINTER_SIZE)) > 0)
 715     return false;
 716
 717   /* Assuming that types whose size is <= pointer-size
 718      are naturally aligned.  */
 719   return true;
 720 }
 721
 722 bool
 723 default_hard_regno_scratch_ok (unsigned int regno ATTRIBUTE_UNUSED)
 724 {
 725   return true;
 726 }
 727
 728 bool
 729 default_target_option_valid_attribute_p (tree ARG_UNUSED (fndecl),
 730                                          tree ARG_UNUSED (name),
 731                                          tree ARG_UNUSED (args),
 732                                          int ARG_UNUSED (flags))
 733 {
 734   warning (OPT_Wattributes,
 735            "target attribute is not supported on this machine");
 736
 737   return false;
 738 }
 739
 740 bool
 741 default_target_option_pragma_parse (tree ARG_UNUSED (args),
 742                                     tree ARG_UNUSED (pop_target))
 743 {
 744   warning (OPT_Wpragmas,
 745            "#pragma GCC target is not supported for this machine");
 746
 747   return false;
 748 }
 749
 750 bool
 751 default_target_option_can_inline_p (tree caller, tree callee)
 752 {
 753   bool ret = false;
 754   tree callee_opts = DECL_FUNCTION_SPECIFIC_TARGET (callee);
 755   tree caller_opts = DECL_FUNCTION_SPECIFIC_TARGET (caller);
 756
 757   /* If callee has no option attributes, then it is ok to inline */
 758   if (!callee_opts)
 759     ret = true;
 760
 761   /* If caller has no option attributes, but callee does then it is not ok to
 762      inline */
 763   else if (!caller_opts)
 764     ret = false;
 765
 766   /* If both caller and callee have attributes, assume that if the pointer is
 767      different, the the two functions have different target options since
 768      build_target_option_node uses a hash table for the options.  */
 769   else
 770     ret = (callee_opts == caller_opts);
 771
 772   return ret;
 773 }
 774
 775 #ifndef HAVE_casesi
 776 # define HAVE_casesi 0
 777 #endif
 778
 779 /* If the machine does not have a case insn that compares the bounds,
 780    this means extra overhead for dispatch tables, which raises the
 781    threshold for using them.  */
 782
 783 unsigned int default_case_values_threshold (void)
 784 {
 785   return (HAVE_casesi ? 4 : 5);
 786 }
 787
 788 #include "gt-targhooks.h"