gcc/targhooks.c

   1 /* Default target hook functions.
   2    Copyright (C) 2003, 2004, 2005, 2007, 2008, 2009, 2010
   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 "toplev.h"
  61 #include "function.h"
  62 #include "target.h"
  63 #include "tm_p.h"
  64 #include "target-def.h"
  65 #include "ggc.h"
  66 #include "hard-reg-set.h"
  67 #include "regs.h"
  68 #include "reload.h"
  69 #include "optabs.h"
  70 #include "recog.h"
  71
  72
  73 bool
  74 default_legitimate_address_p (enum machine_mode mode ATTRIBUTE_UNUSED,
  75                               rtx addr ATTRIBUTE_UNUSED,
  76                               bool strict ATTRIBUTE_UNUSED)
  77 {
  78 #ifdef GO_IF_LEGITIMATE_ADDRESS
  79   /* Defer to the old implementation using a goto.  */
  80   if (strict)
  81     return strict_memory_address_p (mode, addr);
  82   else
  83     return memory_address_p (mode, addr);
  84 #else
  85   gcc_unreachable ();
  86 #endif
  87 }
  88
  89 void
  90 default_external_libcall (rtx fun ATTRIBUTE_UNUSED)
  91 {
  92 #ifdef ASM_OUTPUT_EXTERNAL_LIBCALL
  93   ASM_OUTPUT_EXTERNAL_LIBCALL(asm_out_file, fun);
  94 #endif
  95 }
  96
  97 int
  98 default_unspec_may_trap_p (const_rtx x, unsigned flags)
  99 {
 100   int i;
 101
 102   if (GET_CODE (x) == UNSPEC_VOLATILE
 103       /* Any floating arithmetic may trap.  */
 104       || (SCALAR_FLOAT_MODE_P (GET_MODE (x))
 105           && 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 (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 *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 *ca ATTRIBUTE_UNUSED)
 190 {
 191   return false;
 192 }
 193
 194 bool
 195 default_pretend_outgoing_varargs_named (CUMULATIVE_ARGS *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 * 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 *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 *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_ASM_OUTPUT_ADDR_CONST_EXTRA.  */
 361
 362 bool
 363 default_asm_output_addr_const_extra (FILE *file ATTRIBUTE_UNUSED,
 364                                      rtx x ATTRIBUTE_UNUSED)
 365 {
 366 #ifdef OUTPUT_ADDR_CONST_EXTRA
 367   OUTPUT_ADDR_CONST_EXTRA (file, x, fail);
 368   return true;
 369
 370 fail:
 371 #endif
 372   return false;
 373 }
 374
 375 /* True if MODE is valid for the target.  By "valid", we mean able to
 376    be manipulated in non-trivial ways.  In particular, this means all
 377    the arithmetic is supported.
 378
 379    By default we guess this means that any C type is supported.  If
 380    we can't map the mode back to a type that would be available in C,
 381    then reject it.  Special case, here, is the double-word arithmetic
 382    supported by optabs.c.  */
 383
 384 bool
 385 default_scalar_mode_supported_p (enum machine_mode mode)
 386 {
 387   int precision = GET_MODE_PRECISION (mode);
 388
 389   switch (GET_MODE_CLASS (mode))
 390     {
 391     case MODE_PARTIAL_INT:
 392     case MODE_INT:
 393       if (precision == CHAR_TYPE_SIZE)
 394         return true;
 395       if (precision == SHORT_TYPE_SIZE)
 396         return true;
 397       if (precision == INT_TYPE_SIZE)
 398         return true;
 399       if (precision == LONG_TYPE_SIZE)
 400         return true;
 401       if (precision == LONG_LONG_TYPE_SIZE)
 402         return true;
 403       if (precision == 2 * BITS_PER_WORD)
 404         return true;
 405       return false;
 406
 407     case MODE_FLOAT:
 408       if (precision == FLOAT_TYPE_SIZE)
 409         return true;
 410       if (precision == DOUBLE_TYPE_SIZE)
 411         return true;
 412       if (precision == LONG_DOUBLE_TYPE_SIZE)
 413         return true;
 414       return false;
 415
 416     case MODE_DECIMAL_FLOAT:
 417     case MODE_FRACT:
 418     case MODE_UFRACT:
 419     case MODE_ACCUM:
 420     case MODE_UACCUM:
 421       return false;
 422
 423     default:
 424       gcc_unreachable ();
 425     }
 426 }
 427
 428 /* True if the target supports decimal floating point.  */
 429
 430 bool
 431 default_decimal_float_supported_p (void)
 432 {
 433   return ENABLE_DECIMAL_FLOAT;
 434 }
 435
 436 /* True if the target supports fixed-point arithmetic.  */
 437
 438 bool
 439 default_fixed_point_supported_p (void)
 440 {
 441   return ENABLE_FIXED_POINT;
 442 }
 443
 444 /* NULL if INSN insn is valid within a low-overhead loop, otherwise returns
 445    an error message.
 446
 447    This function checks whether a given INSN is valid within a low-overhead
 448    loop.  If INSN is invalid it returns the reason for that, otherwise it
 449    returns NULL. A called function may clobber any special registers required
 450    for low-overhead looping. Additionally, some targets (eg, PPC) use the count
 451    register for branch on table instructions. We reject the doloop pattern in
 452    these cases.  */
 453
 454 const char *
 455 default_invalid_within_doloop (const_rtx insn)
 456 {
 457   if (CALL_P (insn))
 458     return "Function call in loop.";
 459
 460   if (JUMP_TABLE_DATA_P (insn))
 461     return "Computed branch in the loop.";
 462
 463   return NULL;
 464 }
 465
 466 /* Mapping of builtin functions to vectorized variants.  */
 467
 468 tree
 469 default_builtin_vectorized_function (tree fndecl ATTRIBUTE_UNUSED,
 470                                      tree type_out ATTRIBUTE_UNUSED,
 471                                      tree type_in ATTRIBUTE_UNUSED)
 472 {
 473   return NULL_TREE;
 474 }
 475
 476 /* Vectorized conversion.  */
 477
 478 tree
 479 default_builtin_vectorized_conversion (unsigned int code ATTRIBUTE_UNUSED,
 480                                        tree dest_type ATTRIBUTE_UNUSED,
 481                                        tree src_type ATTRIBUTE_UNUSED)
 482 {
 483   return NULL_TREE;
 484 }
 485
 486 /* Default vectorizer cost model values.  */
 487
 488 int
 489 default_builtin_vectorization_cost (enum vect_cost_for_stmt type_of_cost,
 490                                     tree vectype ATTRIBUTE_UNUSED,
 491                                     int misalign ATTRIBUTE_UNUSED)
 492 {
 493   switch (type_of_cost)
 494     {
 495       case scalar_stmt:
 496       case scalar_load:
 497       case scalar_store:
 498       case vector_stmt:
 499       case vector_load:
 500       case vector_store:
 501       case vec_to_scalar:
 502       case scalar_to_vec:
 503       case cond_branch_not_taken:
 504       case vec_perm:
 505         return 1;
 506
 507       case unaligned_load:
 508       case unaligned_store:
 509         return 2;
 510
 511       case cond_branch_taken:
 512         return 3;
 513
 514       default:
 515         gcc_unreachable ();
 516     }
 517 }
 518
 519 /* Reciprocal.  */
 520
 521 tree
 522 default_builtin_reciprocal (unsigned int fn ATTRIBUTE_UNUSED,
 523                             bool md_fn ATTRIBUTE_UNUSED,
 524                             bool sqrt ATTRIBUTE_UNUSED)
 525 {
 526   return NULL_TREE;
 527 }
 528
 529 bool
 530 hook_bool_CUMULATIVE_ARGS_mode_tree_bool_false (
 531         CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
 532         enum machine_mode mode ATTRIBUTE_UNUSED,
 533         const_tree type ATTRIBUTE_UNUSED, bool named ATTRIBUTE_UNUSED)
 534 {
 535   return false;
 536 }
 537
 538 bool
 539 hook_bool_CUMULATIVE_ARGS_mode_tree_bool_true (
 540         CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
 541         enum machine_mode mode ATTRIBUTE_UNUSED,
 542         const_tree type ATTRIBUTE_UNUSED, bool named ATTRIBUTE_UNUSED)
 543 {
 544   return true;
 545 }
 546
 547 int
 548 hook_int_CUMULATIVE_ARGS_mode_tree_bool_0 (
 549         CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
 550         enum machine_mode mode ATTRIBUTE_UNUSED,
 551         tree type ATTRIBUTE_UNUSED, bool named ATTRIBUTE_UNUSED)
 552 {
 553   return 0;
 554 }
 555
 556 void
 557 default_function_arg_advance (CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
 558                               enum machine_mode mode ATTRIBUTE_UNUSED,
 559                               const_tree type ATTRIBUTE_UNUSED,
 560                               bool named ATTRIBUTE_UNUSED)
 561 {
 562 #ifdef FUNCTION_ARG_ADVANCE
 563   CUMULATIVE_ARGS args = *ca;
 564   FUNCTION_ARG_ADVANCE (args, mode, CONST_CAST_TREE (type), named);
 565   *ca = args;
 566 #else
 567   gcc_unreachable ();
 568 #endif
 569 }
 570
 571 rtx
 572 default_function_arg (CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
 573                       enum machine_mode mode ATTRIBUTE_UNUSED,
 574                       const_tree type ATTRIBUTE_UNUSED,
 575                       bool named ATTRIBUTE_UNUSED)
 576 {
 577 #ifdef FUNCTION_ARG
 578   return FUNCTION_ARG (*ca, mode, CONST_CAST_TREE (type), named);
 579 #else
 580   gcc_unreachable ();
 581 #endif
 582 }
 583
 584 rtx
 585 default_function_incoming_arg (CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
 586                                enum machine_mode mode ATTRIBUTE_UNUSED,
 587                                const_tree type ATTRIBUTE_UNUSED,
 588                                bool named ATTRIBUTE_UNUSED)
 589 {
 590 #ifdef FUNCTION_INCOMING_ARG
 591   return FUNCTION_INCOMING_ARG (*ca, mode, CONST_CAST_TREE (type), named);
 592 #else
 593   gcc_unreachable ();
 594 #endif
 595 }
 596
 597 void
 598 hook_void_bitmap (bitmap regs ATTRIBUTE_UNUSED)
 599 {
 600 }
 601
 602 const char *
 603 hook_invalid_arg_for_unprototyped_fn (
 604         const_tree typelist ATTRIBUTE_UNUSED,
 605         const_tree funcdecl ATTRIBUTE_UNUSED,
 606         const_tree val ATTRIBUTE_UNUSED)
 607 {
 608   return NULL;
 609 }
 610
 611 /* Initialize the stack protection decls.  */
 612
 613 /* Stack protection related decls living in libgcc.  */
 614 static GTY(()) tree stack_chk_guard_decl;
 615
 616 tree
 617 default_stack_protect_guard (void)
 618 {
 619   tree t = stack_chk_guard_decl;
 620
 621   if (t == NULL)
 622     {
 623       rtx x;
 624
 625       t = build_decl (UNKNOWN_LOCATION,
 626                       VAR_DECL, get_identifier ("__stack_chk_guard"),
 627                       ptr_type_node);
 628       TREE_STATIC (t) = 1;
 629       TREE_PUBLIC (t) = 1;
 630       DECL_EXTERNAL (t) = 1;
 631       TREE_USED (t) = 1;
 632       TREE_THIS_VOLATILE (t) = 1;
 633       DECL_ARTIFICIAL (t) = 1;
 634       DECL_IGNORED_P (t) = 1;
 635
 636       /* Do not share RTL as the declaration is visible outside of
 637          current function.  */
 638       x = DECL_RTL (t);
 639       RTX_FLAG (x, used) = 1;
 640
 641       stack_chk_guard_decl = t;
 642     }
 643
 644   return t;
 645 }
 646
 647 static GTY(()) tree stack_chk_fail_decl;
 648
 649 tree
 650 default_external_stack_protect_fail (void)
 651 {
 652   tree t = stack_chk_fail_decl;
 653
 654   if (t == NULL_TREE)
 655     {
 656       t = build_function_type_list (void_type_node, NULL_TREE);
 657       t = build_decl (UNKNOWN_LOCATION,
 658                       FUNCTION_DECL, get_identifier ("__stack_chk_fail"), t);
 659       TREE_STATIC (t) = 1;
 660       TREE_PUBLIC (t) = 1;
 661       DECL_EXTERNAL (t) = 1;
 662       TREE_USED (t) = 1;
 663       TREE_THIS_VOLATILE (t) = 1;
 664       TREE_NOTHROW (t) = 1;
 665       DECL_ARTIFICIAL (t) = 1;
 666       DECL_IGNORED_P (t) = 1;
 667       DECL_VISIBILITY (t) = VISIBILITY_DEFAULT;
 668       DECL_VISIBILITY_SPECIFIED (t) = 1;
 669
 670       stack_chk_fail_decl = t;
 671     }
 672
 673   return build_call_expr (t, 0);
 674 }
 675
 676 tree
 677 default_hidden_stack_protect_fail (void)
 678 {
 679 #ifndef HAVE_GAS_HIDDEN
 680   return default_external_stack_protect_fail ();
 681 #else
 682   tree t = stack_chk_fail_decl;
 683
 684   if (!flag_pic)
 685     return default_external_stack_protect_fail ();
 686
 687   if (t == NULL_TREE)
 688     {
 689       t = build_function_type_list (void_type_node, NULL_TREE);
 690       t = build_decl (UNKNOWN_LOCATION, FUNCTION_DECL,
 691                       get_identifier ("__stack_chk_fail_local"), t);
 692       TREE_STATIC (t) = 1;
 693       TREE_PUBLIC (t) = 1;
 694       DECL_EXTERNAL (t) = 1;
 695       TREE_USED (t) = 1;
 696       TREE_THIS_VOLATILE (t) = 1;
 697       TREE_NOTHROW (t) = 1;
 698       DECL_ARTIFICIAL (t) = 1;
 699       DECL_IGNORED_P (t) = 1;
 700       DECL_VISIBILITY_SPECIFIED (t) = 1;
 701       DECL_VISIBILITY (t) = VISIBILITY_HIDDEN;
 702
 703       stack_chk_fail_decl = t;
 704     }
 705
 706   return build_call_expr (t, 0);
 707 #endif
 708 }
 709
 710 bool
 711 hook_bool_const_rtx_commutative_p (const_rtx x,
 712                                    int outer_code ATTRIBUTE_UNUSED)
 713 {
 714   return COMMUTATIVE_P (x);
 715 }
 716
 717 rtx
 718 default_function_value (const_tree ret_type ATTRIBUTE_UNUSED,
 719                         const_tree fn_decl_or_type,
 720                         bool outgoing ATTRIBUTE_UNUSED)
 721 {
 722   /* The old interface doesn't handle receiving the function type.  */
 723   if (fn_decl_or_type
 724       && !DECL_P (fn_decl_or_type))
 725     fn_decl_or_type = NULL;
 726
 727 #ifdef FUNCTION_VALUE
 728   return FUNCTION_VALUE (ret_type, fn_decl_or_type);
 729 #else
 730   gcc_unreachable ();
 731 #endif
 732 }
 733
 734 rtx
 735 default_libcall_value (enum machine_mode mode ATTRIBUTE_UNUSED,
 736                        const_rtx fun ATTRIBUTE_UNUSED)
 737 {
 738 #ifdef LIBCALL_VALUE
 739   return LIBCALL_VALUE (mode);
 740 #else
 741   gcc_unreachable ();
 742 #endif
 743 }
 744
 745 /* The default hook for TARGET_FUNCTION_VALUE_REGNO_P.  */
 746
 747 bool
 748 default_function_value_regno_p (const unsigned int regno ATTRIBUTE_UNUSED)
 749 {
 750 #ifdef FUNCTION_VALUE_REGNO_P
 751   return FUNCTION_VALUE_REGNO_P (regno);
 752 #else
 753   gcc_unreachable ();
 754 #endif
 755 }
 756
 757 rtx
 758 default_internal_arg_pointer (void)
 759 {
 760   /* If the reg that the virtual arg pointer will be translated into is
 761      not a fixed reg or is the stack pointer, make a copy of the virtual
 762      arg pointer, and address parms via the copy.  The frame pointer is
 763      considered fixed even though it is not marked as such.  */
 764   if ((ARG_POINTER_REGNUM == STACK_POINTER_REGNUM
 765        || ! (fixed_regs[ARG_POINTER_REGNUM]
 766              || ARG_POINTER_REGNUM == FRAME_POINTER_REGNUM)))
 767     return copy_to_reg (virtual_incoming_args_rtx);
 768   else
 769     return virtual_incoming_args_rtx;
 770 }
 771
 772 rtx
 773 default_static_chain (const_tree fndecl, bool incoming_p)
 774 {
 775   if (!DECL_STATIC_CHAIN (fndecl))
 776     return NULL;
 777
 778   if (incoming_p)
 779     {
 780 #ifdef STATIC_CHAIN_INCOMING_REGNUM
 781       return gen_rtx_REG (Pmode, STATIC_CHAIN_INCOMING_REGNUM);
 782 #endif
 783     }
 784
 785 #ifdef STATIC_CHAIN_REGNUM
 786   return gen_rtx_REG (Pmode, STATIC_CHAIN_REGNUM);
 787 #endif
 788
 789   {
 790     static bool issued_error;
 791     if (!issued_error)
 792       {
 793         issued_error = true;
 794         sorry ("nested functions not supported on this target");
 795       }
 796
 797     /* It really doesn't matter what we return here, so long at it
 798        doesn't cause the rest of the compiler to crash.  */
 799     return gen_rtx_MEM (Pmode, stack_pointer_rtx);
 800   }
 801 }
 802
 803 void
 804 default_trampoline_init (rtx ARG_UNUSED (m_tramp), tree ARG_UNUSED (t_func),
 805                          rtx ARG_UNUSED (r_chain))
 806 {
 807   sorry ("nested function trampolines not supported on this target");
 808 }
 809
 810 int
 811 default_return_pops_args (tree fundecl ATTRIBUTE_UNUSED,
 812                           tree funtype ATTRIBUTE_UNUSED,
 813                           int size ATTRIBUTE_UNUSED)
 814 {
 815   return 0;
 816 }
 817
 818 reg_class_t
 819 default_branch_target_register_class (void)
 820 {
 821   return NO_REGS;
 822 }
 823
 824 #ifdef IRA_COVER_CLASSES
 825 const reg_class_t *
 826 default_ira_cover_classes (void)
 827 {
 828   static reg_class_t classes[] = IRA_COVER_CLASSES;
 829   return classes;
 830 }
 831 #endif
 832
 833 reg_class_t
 834 default_secondary_reload (bool in_p ATTRIBUTE_UNUSED, rtx x ATTRIBUTE_UNUSED,
 835                           reg_class_t reload_class_i ATTRIBUTE_UNUSED,
 836                           enum machine_mode reload_mode ATTRIBUTE_UNUSED,
 837                           secondary_reload_info *sri)
 838 {
 839   enum reg_class rclass = NO_REGS;
 840   enum reg_class reload_class = (enum reg_class) reload_class_i;
 841
 842   if (sri->prev_sri && sri->prev_sri->t_icode != CODE_FOR_nothing)
 843     {
 844       sri->icode = sri->prev_sri->t_icode;
 845       return NO_REGS;
 846     }
 847 #ifdef SECONDARY_INPUT_RELOAD_CLASS
 848   if (in_p)
 849     rclass = SECONDARY_INPUT_RELOAD_CLASS (reload_class, reload_mode, x);
 850 #endif
 851 #ifdef SECONDARY_OUTPUT_RELOAD_CLASS
 852   if (! in_p)
 853     rclass = SECONDARY_OUTPUT_RELOAD_CLASS (reload_class, reload_mode, x);
 854 #endif
 855   if (rclass != NO_REGS)
 856     {
 857       enum insn_code icode
 858         = direct_optab_handler (in_p ? reload_in_optab : reload_out_optab,
 859                                 reload_mode);
 860
 861       if (icode != CODE_FOR_nothing
 862           && insn_data[(int) icode].operand[in_p].predicate
 863           && ! insn_data[(int) icode].operand[in_p].predicate (x, reload_mode))
 864         icode = CODE_FOR_nothing;
 865       else if (icode != CODE_FOR_nothing)
 866         {
 867           const char *insn_constraint, *scratch_constraint;
 868           char insn_letter, scratch_letter;
 869           enum reg_class insn_class, scratch_class;
 870
 871           gcc_assert (insn_data[(int) icode].n_operands == 3);
 872           insn_constraint = insn_data[(int) icode].operand[!in_p].constraint;
 873           if (!*insn_constraint)
 874             insn_class = ALL_REGS;
 875           else
 876             {
 877               if (in_p)
 878                 {
 879                   gcc_assert (*insn_constraint == '=');
 880                   insn_constraint++;
 881                 }
 882               insn_letter = *insn_constraint;
 883               insn_class
 884                 = (insn_letter == 'r' ? GENERAL_REGS
 885                    : REG_CLASS_FROM_CONSTRAINT ((unsigned char) insn_letter,
 886                                                 insn_constraint));
 887               gcc_assert (insn_class != NO_REGS);
 888             }
 889
 890           scratch_constraint = insn_data[(int) icode].operand[2].constraint;
 891           /* The scratch register's constraint must start with "=&",
 892              except for an input reload, where only "=" is necessary,
 893              and where it might be beneficial to re-use registers from
 894              the input.  */
 895           gcc_assert (scratch_constraint[0] == '='
 896                       && (in_p || scratch_constraint[1] == '&'));
 897           scratch_constraint++;
 898           if (*scratch_constraint == '&')
 899             scratch_constraint++;
 900           scratch_letter = *scratch_constraint;
 901           scratch_class
 902             = (scratch_letter == 'r' ? GENERAL_REGS
 903                : REG_CLASS_FROM_CONSTRAINT ((unsigned char) scratch_letter,
 904                                             scratch_constraint));
 905
 906           if (reg_class_subset_p (reload_class, insn_class))
 907             {
 908               gcc_assert (scratch_class == rclass);
 909               rclass = NO_REGS;
 910             }
 911           else
 912             rclass = insn_class;
 913
 914         }
 915       if (rclass == NO_REGS)
 916         sri->icode = icode;
 917       else
 918         sri->t_icode = icode;
 919     }
 920   return rclass;
 921 }
 922
 923 bool
 924 default_handle_c_option (size_t code ATTRIBUTE_UNUSED,
 925                          const char *arg ATTRIBUTE_UNUSED,
 926                          int value ATTRIBUTE_UNUSED)
 927 {
 928   return false;
 929 }
 930
 931 /* By default, if flag_pic is true, then neither local nor global relocs
 932    should be placed in readonly memory.  */
 933
 934 int
 935 default_reloc_rw_mask (void)
 936 {
 937   return flag_pic ? 3 : 0;
 938 }
 939
 940 /* By default, do no modification. */
 941 tree default_mangle_decl_assembler_name (tree decl ATTRIBUTE_UNUSED,
 942                                          tree id)
 943 {
 944    return id;
 945 }
 946
 947 bool
 948 default_builtin_vector_alignment_reachable (const_tree type, bool is_packed)
 949 {
 950   if (is_packed)
 951     return false;
 952
 953   /* Assuming that types whose size is > pointer-size are not guaranteed to be
 954      naturally aligned.  */
 955   if (tree_int_cst_compare (TYPE_SIZE (type), bitsize_int (POINTER_SIZE)) > 0)
 956     return false;
 957
 958   /* Assuming that types whose size is <= pointer-size
 959      are naturally aligned.  */
 960   return true;
 961 }
 962
 963 /* By default, assume that a target supports any factor of misalignment
 964    memory access if it supports movmisalign patten.
 965    is_packed is true if the memory access is defined in a packed struct.  */
 966 bool
 967 default_builtin_support_vector_misalignment (enum machine_mode mode,
 968                                              const_tree type
 969                                              ATTRIBUTE_UNUSED,
 970                                              int misalignment
 971                                              ATTRIBUTE_UNUSED,
 972                                              bool is_packed
 973                                              ATTRIBUTE_UNUSED)
 974 {
 975   if (optab_handler (movmisalign_optab, mode) != CODE_FOR_nothing)
 976     return true;
 977   return false;
 978 }
 979
 980 /* By default, only attempt to parallelize bitwise operations, and
 981    possibly adds/subtracts using bit-twiddling.  */
 982
 983 enum machine_mode
 984 default_preferred_simd_mode (enum machine_mode mode ATTRIBUTE_UNUSED)
 985 {
 986   return word_mode;
 987 }
 988
 989 /* By default only the size derived from the preferred vector mode
 990    is tried.  */
 991
 992 unsigned int
 993 default_autovectorize_vector_sizes (void)
 994 {
 995   return 0;
 996 }
 997
 998 /* Determine whether or not a pointer mode is valid. Assume defaults
 999    of ptr_mode or Pmode - can be overridden.  */
1000 bool
1001 default_valid_pointer_mode (enum machine_mode mode)
1002 {
1003   return (mode == ptr_mode || mode == Pmode);
1004 }
1005
1006 /* Return the mode for a pointer to a given ADDRSPACE, defaulting to ptr_mode
1007    for the generic address space only.  */
1008
1009 enum machine_mode
1010 default_addr_space_pointer_mode (addr_space_t addrspace ATTRIBUTE_UNUSED)
1011 {
1012   gcc_assert (ADDR_SPACE_GENERIC_P (addrspace));
1013   return ptr_mode;
1014 }
1015
1016 /* Return the mode for an address in a given ADDRSPACE, defaulting to Pmode
1017    for the generic address space only.  */
1018
1019 enum machine_mode
1020 default_addr_space_address_mode (addr_space_t addrspace ATTRIBUTE_UNUSED)
1021 {
1022   gcc_assert (ADDR_SPACE_GENERIC_P (addrspace));
1023   return Pmode;
1024 }
1025
1026 /* Named address space version of valid_pointer_mode.  */
1027
1028 bool
1029 default_addr_space_valid_pointer_mode (enum machine_mode mode, addr_space_t as)
1030 {
1031   if (!ADDR_SPACE_GENERIC_P (as))
1032     return (mode == targetm.addr_space.pointer_mode (as)
1033             || mode == targetm.addr_space.address_mode (as));
1034
1035   return targetm.valid_pointer_mode (mode);
1036 }
1037
1038 /* Some places still assume that all pointer or address modes are the
1039    standard Pmode and ptr_mode.  These optimizations become invalid if
1040    the target actually supports multiple different modes.  For now,
1041    we disable such optimizations on such targets, using this function.  */
1042
1043 bool
1044 target_default_pointer_address_modes_p (void)
1045 {
1046   if (targetm.addr_space.address_mode != default_addr_space_address_mode)
1047     return false;
1048   if (targetm.addr_space.pointer_mode != default_addr_space_pointer_mode)
1049     return false;
1050
1051   return true;
1052 }
1053
1054 /* Named address space version of legitimate_address_p.  */
1055
1056 bool
1057 default_addr_space_legitimate_address_p (enum machine_mode mode, rtx mem,
1058                                          bool strict, addr_space_t as)
1059 {
1060   if (!ADDR_SPACE_GENERIC_P (as))
1061     gcc_unreachable ();
1062
1063   return targetm.legitimate_address_p (mode, mem, strict);
1064 }
1065
1066 /* Named address space version of LEGITIMIZE_ADDRESS.  */
1067
1068 rtx
1069 default_addr_space_legitimize_address (rtx x, rtx oldx,
1070                                        enum machine_mode mode, addr_space_t as)
1071 {
1072   if (!ADDR_SPACE_GENERIC_P (as))
1073     return x;
1074
1075   return targetm.legitimize_address (x, oldx, mode);
1076 }
1077
1078 /* The default hook for determining if one named address space is a subset of
1079    another and to return which address space to use as the common address
1080    space.  */
1081
1082 bool
1083 default_addr_space_subset_p (addr_space_t subset, addr_space_t superset)
1084 {
1085   return (subset == superset);
1086 }
1087
1088 /* The default hook for TARGET_ADDR_SPACE_CONVERT. This hook should never be
1089    called for targets with only a generic address space.  */
1090
1091 rtx
1092 default_addr_space_convert (rtx op ATTRIBUTE_UNUSED,
1093                             tree from_type ATTRIBUTE_UNUSED,
1094                             tree to_type ATTRIBUTE_UNUSED)
1095 {
1096   gcc_unreachable ();
1097 }
1098
1099 bool
1100 default_hard_regno_scratch_ok (unsigned int regno ATTRIBUTE_UNUSED)
1101 {
1102   return true;
1103 }
1104
1105 /* The default implementation of TARGET_MODE_DEPENDENT_ADDRESS_P.  */
1106
1107 bool
1108 default_mode_dependent_address_p (const_rtx addr ATTRIBUTE_UNUSED)
1109 {
1110 #ifdef GO_IF_MODE_DEPENDENT_ADDRESS
1111
1112   GO_IF_MODE_DEPENDENT_ADDRESS (CONST_CAST_RTX (addr), win);
1113   return false;
1114   /* Label `win' might (not) be used via GO_IF_MODE_DEPENDENT_ADDRESS.  */
1115  win: ATTRIBUTE_UNUSED_LABEL
1116   return true;
1117
1118 #else
1119
1120   return false;
1121
1122 #endif
1123 }
1124
1125 bool
1126 default_target_option_valid_attribute_p (tree ARG_UNUSED (fndecl),
1127                                          tree ARG_UNUSED (name),
1128                                          tree ARG_UNUSED (args),
1129                                          int ARG_UNUSED (flags))
1130 {
1131   warning (OPT_Wattributes,
1132            "target attribute is not supported on this machine");
1133
1134   return false;
1135 }
1136
1137 bool
1138 default_target_option_pragma_parse (tree ARG_UNUSED (args),
1139                                     tree ARG_UNUSED (pop_target))
1140 {
1141   warning (OPT_Wpragmas,
1142            "#pragma GCC target is not supported for this machine");
1143
1144   return false;
1145 }
1146
1147 bool
1148 default_target_can_inline_p (tree caller, tree callee)
1149 {
1150   bool ret = false;
1151   tree callee_opts = DECL_FUNCTION_SPECIFIC_TARGET (callee);
1152   tree caller_opts = DECL_FUNCTION_SPECIFIC_TARGET (caller);
1153
1154   /* If callee has no option attributes, then it is ok to inline */
1155   if (!callee_opts)
1156     ret = true;
1157
1158   /* If caller has no option attributes, but callee does then it is not ok to
1159      inline */
1160   else if (!caller_opts)
1161     ret = false;
1162
1163   /* If both caller and callee have attributes, assume that if the pointer is
1164      different, the the two functions have different target options since
1165      build_target_option_node uses a hash table for the options.  */
1166   else
1167     ret = (callee_opts == caller_opts);
1168
1169   return ret;
1170 }
1171
1172 #ifndef HAVE_casesi
1173 # define HAVE_casesi 0
1174 #endif
1175
1176 /* If the machine does not have a case insn that compares the bounds,
1177    this means extra overhead for dispatch tables, which raises the
1178    threshold for using them.  */
1179
1180 unsigned int default_case_values_threshold (void)
1181 {
1182   return (HAVE_casesi ? 4 : 5);
1183 }
1184
1185 bool
1186 default_have_conditional_execution (void)
1187 {
1188 #ifdef HAVE_conditional_execution
1189   return HAVE_conditional_execution;
1190 #else
1191   return false;
1192 #endif
1193 }
1194
1195 /* Compute cost of moving registers to/from memory.  */
1196
1197 int
1198 default_memory_move_cost (enum machine_mode mode ATTRIBUTE_UNUSED,
1199                           reg_class_t rclass ATTRIBUTE_UNUSED,
1200                           bool in ATTRIBUTE_UNUSED)
1201 {
1202 #ifndef MEMORY_MOVE_COST
1203     return (4 + memory_move_secondary_cost (mode, (enum reg_class) rclass, in));
1204 #else
1205     return MEMORY_MOVE_COST (mode, (enum reg_class) rclass, in);
1206 #endif
1207 }
1208
1209 /* Compute cost of moving data from a register of class FROM to one of
1210    TO, using MODE.  */
1211
1212 int
1213 default_register_move_cost (enum machine_mode mode ATTRIBUTE_UNUSED,
1214                             reg_class_t from ATTRIBUTE_UNUSED,
1215                             reg_class_t to ATTRIBUTE_UNUSED)
1216 {
1217 #ifndef REGISTER_MOVE_COST
1218   return 2;
1219 #else
1220   return REGISTER_MOVE_COST (mode, (enum reg_class) from, (enum reg_class) to);
1221 #endif
1222 }
1223
1224 bool
1225 default_profile_before_prologue (void)
1226 {
1227 #ifdef PROFILE_BEFORE_PROLOGUE
1228   return true;
1229 #else
1230   return false;
1231 #endif
1232 }
1233
1234 /* The default implementation of TARGET_PREFERRED_RELOAD_CLASS.  */
1235
1236 reg_class_t
1237 default_preferred_reload_class (rtx x ATTRIBUTE_UNUSED,
1238                                 reg_class_t rclass)
1239 {
1240 #ifdef PREFERRED_RELOAD_CLASS
1241   return (reg_class_t) PREFERRED_RELOAD_CLASS (x, (enum reg_class) rclass);
1242 #else
1243   return rclass;
1244 #endif
1245 }
1246
1247 /* The default implementation of TARGET_OUTPUT_PREFERRED_RELOAD_CLASS.  */
1248
1249 reg_class_t
1250 default_preferred_output_reload_class (rtx x ATTRIBUTE_UNUSED,
1251                                        reg_class_t rclass)
1252 {
1253 #ifdef PREFERRED_OUTPUT_RELOAD_CLASS
1254   return PREFERRED_OUTPUT_RELOAD_CLASS (x, (enum reg_class) rclass);
1255 #else
1256   return rclass;
1257 #endif
1258 }
1259
1260 /* The default implementation of TARGET_CLASS_LIKELY_SPILLED_P.  */
1261
1262 bool
1263 default_class_likely_spilled_p (reg_class_t rclass)
1264 {
1265   return (reg_class_size[(int) rclass] == 1);
1266 }
1267
1268 /* Determine the debugging unwind mechanism for the target.  */
1269
1270 enum unwind_info_type
1271 default_debug_unwind_info (void)
1272 {
1273   /* If the target wants to force the use of dwarf2 unwind info, let it.  */
1274   /* ??? Change all users to the hook, then poison this.  */
1275 #ifdef DWARF2_FRAME_INFO
1276   if (DWARF2_FRAME_INFO)
1277     return UI_DWARF2;
1278 #endif
1279
1280   /* Otherwise, only turn it on if dwarf2 debugging is enabled.  */
1281 #ifdef DWARF2_DEBUGGING_INFO
1282   if (write_symbols == DWARF2_DEBUG || write_symbols == VMS_AND_DWARF2_DEBUG)
1283     return UI_DWARF2;
1284 #endif
1285
1286   return UI_NONE;
1287 }
1288
1289 /* Determine the exception handling mechanism for the target.  */
1290
1291 enum unwind_info_type
1292 default_except_unwind_info (void)
1293 {
1294   /* ??? Change the one user to the hook, then poison this.  */
1295 #ifdef MUST_USE_SJLJ_EXCEPTIONS
1296   if (MUST_USE_SJLJ_EXCEPTIONS)
1297     return UI_SJLJ;
1298 #endif
1299
1300   /* Obey the configure switch to turn on sjlj exceptions.  */
1301 #ifdef CONFIG_SJLJ_EXCEPTIONS
1302   if (CONFIG_SJLJ_EXCEPTIONS)
1303     return UI_SJLJ;
1304 #endif
1305
1306   /* ??? Change all users to the hook, then poison this.  */
1307 #ifdef DWARF2_UNWIND_INFO
1308   if (DWARF2_UNWIND_INFO)
1309     return UI_DWARF2;
1310 #endif
1311
1312   return UI_SJLJ;
1313 }
1314
1315 /* To be used by targets that force dwarf2 unwind enabled.  */
1316
1317 enum unwind_info_type
1318 dwarf2_except_unwind_info (void)
1319 {
1320   /* Obey the configure switch to turn on sjlj exceptions.  */
1321 #ifdef CONFIG_SJLJ_EXCEPTIONS
1322   if (CONFIG_SJLJ_EXCEPTIONS)
1323     return UI_SJLJ;
1324 #endif
1325
1326   return UI_DWARF2;
1327 }
1328
1329 /* To be used by targets that force sjlj unwind enabled.  */
1330
1331 enum unwind_info_type
1332 sjlj_except_unwind_info (void)
1333 {
1334   return UI_SJLJ;
1335 }
1336
1337 /* To be used by targets where reg_raw_mode doesn't return the right
1338    mode for registers used in apply_builtin_return and apply_builtin_arg.  */
1339
1340 enum machine_mode
1341 default_get_reg_raw_mode(int regno)
1342 {
1343   return reg_raw_mode[regno];
1344 }
1345
1346 const struct default_options empty_optimization_table[] =
1347   {
1348     { OPT_LEVELS_NONE, 0, NULL, 0 }
1349   };
1350
1351 #include "gt-targhooks.h"