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 "reload.h"
  68 #include "optabs.h"
  69 #include "recog.h"
  70
  71
  72 bool
  73 default_legitimate_address_p (enum machine_mode mode ATTRIBUTE_UNUSED,
  74                               rtx addr ATTRIBUTE_UNUSED,
  75                               bool strict ATTRIBUTE_UNUSED)
  76 {
  77 #ifdef GO_IF_LEGITIMATE_ADDRESS
  78   /* Defer to the old implementation using a goto.  */
  79   if (strict)
  80     return strict_memory_address_p (mode, addr);
  81   else
  82     return memory_address_p (mode, addr);
  83 #else
  84   gcc_unreachable ();
  85 #endif
  86 }
  87
  88 void
  89 default_external_libcall (rtx fun ATTRIBUTE_UNUSED)
  90 {
  91 #ifdef ASM_OUTPUT_EXTERNAL_LIBCALL
  92   ASM_OUTPUT_EXTERNAL_LIBCALL(asm_out_file, fun);
  93 #endif
  94 }
  95
  96 int
  97 default_unspec_may_trap_p (const_rtx x, unsigned flags)
  98 {
  99   int i;
 100
 101   if (GET_CODE (x) == UNSPEC_VOLATILE
 102       /* Any floating arithmetic may trap.  */
 103       || (SCALAR_FLOAT_MODE_P (GET_MODE (x))
 104           && flag_trapping_math))
 105     return 1;
 106
 107   for (i = 0; i < XVECLEN (x, 0); ++i)
 108     {
 109       if (may_trap_p_1 (XVECEXP (x, 0, i), flags))
 110         return 1;
 111     }
 112
 113   return 0;
 114 }
 115
 116 enum machine_mode
 117 default_promote_function_mode (const_tree type ATTRIBUTE_UNUSED,
 118                                enum machine_mode mode,
 119                                int *punsignedp ATTRIBUTE_UNUSED,
 120                                const_tree funtype ATTRIBUTE_UNUSED,
 121                                int for_return ATTRIBUTE_UNUSED)
 122 {
 123   if (for_return == 2)
 124     return promote_mode (type, mode, punsignedp);
 125   return mode;
 126 }
 127
 128 enum machine_mode
 129 default_promote_function_mode_always_promote (const_tree type,
 130                                               enum machine_mode mode,
 131                                               int *punsignedp,
 132                                               const_tree funtype ATTRIBUTE_UNUSED,
 133                                               int for_return ATTRIBUTE_UNUSED)
 134 {
 135   return promote_mode (type, mode, punsignedp);
 136 }
 137
 138
 139 enum machine_mode
 140 default_cc_modes_compatible (enum machine_mode m1, enum machine_mode m2)
 141 {
 142   if (m1 == m2)
 143     return m1;
 144   return VOIDmode;
 145 }
 146
 147 bool
 148 default_return_in_memory (const_tree type,
 149                           const_tree fntype ATTRIBUTE_UNUSED)
 150 {
 151   return (TYPE_MODE (type) == BLKmode);
 152 }
 153
 154 rtx
 155 default_legitimize_address (rtx x, rtx orig_x ATTRIBUTE_UNUSED,
 156                             enum machine_mode mode ATTRIBUTE_UNUSED)
 157 {
 158   return x;
 159 }
 160
 161 rtx
 162 default_expand_builtin_saveregs (void)
 163 {
 164   error ("__builtin_saveregs not supported by this target");
 165   return const0_rtx;
 166 }
 167
 168 void
 169 default_setup_incoming_varargs (CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
 170                                 enum machine_mode mode ATTRIBUTE_UNUSED,
 171                                 tree type ATTRIBUTE_UNUSED,
 172                                 int *pretend_arg_size ATTRIBUTE_UNUSED,
 173                                 int second_time ATTRIBUTE_UNUSED)
 174 {
 175 }
 176
 177 /* The default implementation of TARGET_BUILTIN_SETJMP_FRAME_VALUE.  */
 178
 179 rtx
 180 default_builtin_setjmp_frame_value (void)
 181 {
 182   return virtual_stack_vars_rtx;
 183 }
 184
 185 /* Generic hook that takes a CUMULATIVE_ARGS pointer and returns false.  */
 186
 187 bool
 188 hook_bool_CUMULATIVE_ARGS_false (CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED)
 189 {
 190   return false;
 191 }
 192
 193 bool
 194 default_pretend_outgoing_varargs_named (CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED)
 195 {
 196   return (targetm.calls.setup_incoming_varargs
 197           != default_setup_incoming_varargs);
 198 }
 199
 200 enum machine_mode
 201 default_eh_return_filter_mode (void)
 202 {
 203   return targetm.unwind_word_mode ();
 204 }
 205
 206 enum machine_mode
 207 default_libgcc_cmp_return_mode (void)
 208 {
 209   return word_mode;
 210 }
 211
 212 enum machine_mode
 213 default_libgcc_shift_count_mode (void)
 214 {
 215   return word_mode;
 216 }
 217
 218 enum machine_mode
 219 default_unwind_word_mode (void)
 220 {
 221   return word_mode;
 222 }
 223
 224 /* The default implementation of TARGET_SHIFT_TRUNCATION_MASK.  */
 225
 226 unsigned HOST_WIDE_INT
 227 default_shift_truncation_mask (enum machine_mode mode)
 228 {
 229   return SHIFT_COUNT_TRUNCATED ? GET_MODE_BITSIZE (mode) - 1 : 0;
 230 }
 231
 232 /* The default implementation of TARGET_MIN_DIVISIONS_FOR_RECIP_MUL.  */
 233
 234 unsigned int
 235 default_min_divisions_for_recip_mul (enum machine_mode mode ATTRIBUTE_UNUSED)
 236 {
 237   return have_insn_for (DIV, mode) ? 3 : 2;
 238 }
 239
 240 /* The default implementation of TARGET_MODE_REP_EXTENDED.  */
 241
 242 int
 243 default_mode_rep_extended (enum machine_mode mode ATTRIBUTE_UNUSED,
 244                            enum machine_mode mode_rep ATTRIBUTE_UNUSED)
 245 {
 246   return UNKNOWN;
 247 }
 248
 249 /* Generic hook that takes a CUMULATIVE_ARGS pointer and returns true.  */
 250
 251 bool
 252 hook_bool_CUMULATIVE_ARGS_true (CUMULATIVE_ARGS * a ATTRIBUTE_UNUSED)
 253 {
 254   return true;
 255 }
 256
 257 /* Return machine mode for non-standard suffix
 258    or VOIDmode if non-standard suffixes are unsupported.  */
 259 enum machine_mode
 260 default_mode_for_suffix (char suffix ATTRIBUTE_UNUSED)
 261 {
 262   return VOIDmode;
 263 }
 264
 265 /* The generic C++ ABI specifies this is a 64-bit value.  */
 266 tree
 267 default_cxx_guard_type (void)
 268 {
 269   return long_long_integer_type_node;
 270 }
 271
 272
 273 /* Returns the size of the cookie to use when allocating an array
 274    whose elements have the indicated TYPE.  Assumes that it is already
 275    known that a cookie is needed.  */
 276
 277 tree
 278 default_cxx_get_cookie_size (tree type)
 279 {
 280   tree cookie_size;
 281
 282   /* We need to allocate an additional max (sizeof (size_t), alignof
 283      (true_type)) bytes.  */
 284   tree sizetype_size;
 285   tree type_align;
 286
 287   sizetype_size = size_in_bytes (sizetype);
 288   type_align = size_int (TYPE_ALIGN_UNIT (type));
 289   if (INT_CST_LT_UNSIGNED (type_align, sizetype_size))
 290     cookie_size = sizetype_size;
 291   else
 292     cookie_size = type_align;
 293
 294   return cookie_size;
 295 }
 296
 297 /* Return true if a parameter must be passed by reference.  This version
 298    of the TARGET_PASS_BY_REFERENCE hook uses just MUST_PASS_IN_STACK.  */
 299
 300 bool
 301 hook_pass_by_reference_must_pass_in_stack (CUMULATIVE_ARGS *c ATTRIBUTE_UNUSED,
 302         enum machine_mode mode ATTRIBUTE_UNUSED, const_tree type ATTRIBUTE_UNUSED,
 303         bool named_arg ATTRIBUTE_UNUSED)
 304 {
 305   return targetm.calls.must_pass_in_stack (mode, type);
 306 }
 307
 308 /* Return true if a parameter follows callee copies conventions.  This
 309    version of the hook is true for all named arguments.  */
 310
 311 bool
 312 hook_callee_copies_named (CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
 313                           enum machine_mode mode ATTRIBUTE_UNUSED,
 314                           const_tree type ATTRIBUTE_UNUSED, bool named)
 315 {
 316   return named;
 317 }
 318
 319 /* Emit to STREAM the assembler syntax for insn operand X.  */
 320
 321 void
 322 default_print_operand (FILE *stream ATTRIBUTE_UNUSED, rtx x ATTRIBUTE_UNUSED,
 323                        int code ATTRIBUTE_UNUSED)
 324 {
 325 #ifdef PRINT_OPERAND
 326   PRINT_OPERAND (stream, x, code);
 327 #else
 328   gcc_unreachable ();
 329 #endif
 330 }
 331
 332 /* Emit to STREAM the assembler syntax for an insn operand whose memory
 333    address is X.  */
 334
 335 void
 336 default_print_operand_address (FILE *stream ATTRIBUTE_UNUSED,
 337                                rtx x ATTRIBUTE_UNUSED)
 338 {
 339 #ifdef PRINT_OPERAND_ADDRESS
 340   PRINT_OPERAND_ADDRESS (stream, x);
 341 #else
 342   gcc_unreachable ();
 343 #endif
 344 }
 345
 346 /* Return true if CODE is a valid punctuation character for the
 347    `print_operand' hook.  */
 348
 349 bool
 350 default_print_operand_punct_valid_p (unsigned char code ATTRIBUTE_UNUSED)
 351 {
 352 #ifdef PRINT_OPERAND_PUNCT_VALID_P
 353   return PRINT_OPERAND_PUNCT_VALID_P (code);
 354 #else
 355   return false;
 356 #endif
 357 }
 358
 359 /* The default implementation of TARGET_ASM_OUTPUT_ADDR_CONST_EXTRA.  */
 360
 361 bool
 362 default_asm_output_addr_const_extra (FILE *file ATTRIBUTE_UNUSED,
 363                                      rtx x ATTRIBUTE_UNUSED)
 364 {
 365 #ifdef OUTPUT_ADDR_CONST_EXTRA
 366   OUTPUT_ADDR_CONST_EXTRA (file, x, fail);
 367   return true;
 368
 369 fail:
 370 #endif
 371   return false;
 372 }
 373
 374 /* True if MODE is valid for the target.  By "valid", we mean able to
 375    be manipulated in non-trivial ways.  In particular, this means all
 376    the arithmetic is supported.
 377
 378    By default we guess this means that any C type is supported.  If
 379    we can't map the mode back to a type that would be available in C,
 380    then reject it.  Special case, here, is the double-word arithmetic
 381    supported by optabs.c.  */
 382
 383 bool
 384 default_scalar_mode_supported_p (enum machine_mode mode)
 385 {
 386   int precision = GET_MODE_PRECISION (mode);
 387
 388   switch (GET_MODE_CLASS (mode))
 389     {
 390     case MODE_PARTIAL_INT:
 391     case MODE_INT:
 392       if (precision == CHAR_TYPE_SIZE)
 393         return true;
 394       if (precision == SHORT_TYPE_SIZE)
 395         return true;
 396       if (precision == INT_TYPE_SIZE)
 397         return true;
 398       if (precision == LONG_TYPE_SIZE)
 399         return true;
 400       if (precision == LONG_LONG_TYPE_SIZE)
 401         return true;
 402       if (precision == 2 * BITS_PER_WORD)
 403         return true;
 404       return false;
 405
 406     case MODE_FLOAT:
 407       if (precision == FLOAT_TYPE_SIZE)
 408         return true;
 409       if (precision == DOUBLE_TYPE_SIZE)
 410         return true;
 411       if (precision == LONG_DOUBLE_TYPE_SIZE)
 412         return true;
 413       return false;
 414
 415     case MODE_DECIMAL_FLOAT:
 416     case MODE_FRACT:
 417     case MODE_UFRACT:
 418     case MODE_ACCUM:
 419     case MODE_UACCUM:
 420       return false;
 421
 422     default:
 423       gcc_unreachable ();
 424     }
 425 }
 426
 427 /* True if the target supports decimal floating point.  */
 428
 429 bool
 430 default_decimal_float_supported_p (void)
 431 {
 432   return ENABLE_DECIMAL_FLOAT;
 433 }
 434
 435 /* True if the target supports fixed-point arithmetic.  */
 436
 437 bool
 438 default_fixed_point_supported_p (void)
 439 {
 440   return ENABLE_FIXED_POINT;
 441 }
 442
 443 /* NULL if INSN insn is valid within a low-overhead loop, otherwise returns
 444    an error message.
 445
 446    This function checks whether a given INSN is valid within a low-overhead
 447    loop.  If INSN is invalid it returns the reason for that, otherwise it
 448    returns NULL. A called function may clobber any special registers required
 449    for low-overhead looping. Additionally, some targets (eg, PPC) use the count
 450    register for branch on table instructions. We reject the doloop pattern in
 451    these cases.  */
 452
 453 const char *
 454 default_invalid_within_doloop (const_rtx insn)
 455 {
 456   if (CALL_P (insn))
 457     return "Function call in loop.";
 458
 459   if (JUMP_TABLE_DATA_P (insn))
 460     return "Computed branch in the loop.";
 461
 462   return NULL;
 463 }
 464
 465 /* Mapping of builtin functions to vectorized variants.  */
 466
 467 tree
 468 default_builtin_vectorized_function (tree fndecl ATTRIBUTE_UNUSED,
 469                                      tree type_out ATTRIBUTE_UNUSED,
 470                                      tree type_in ATTRIBUTE_UNUSED)
 471 {
 472   return NULL_TREE;
 473 }
 474
 475 /* Vectorized conversion.  */
 476
 477 tree
 478 default_builtin_vectorized_conversion (unsigned int code ATTRIBUTE_UNUSED,
 479                                        tree dest_type ATTRIBUTE_UNUSED,
 480                                        tree src_type ATTRIBUTE_UNUSED)
 481 {
 482   return NULL_TREE;
 483 }
 484
 485 /* Default vectorizer cost model values.  */
 486
 487 int
 488 default_builtin_vectorization_cost (enum vect_cost_for_stmt type_of_cost,
 489                                     tree vectype ATTRIBUTE_UNUSED,
 490                                     int misalign ATTRIBUTE_UNUSED)
 491 {
 492   switch (type_of_cost)
 493     {
 494       case scalar_stmt:
 495       case scalar_load:
 496       case scalar_store:
 497       case vector_stmt:
 498       case vector_load:
 499       case vector_store:
 500       case vec_to_scalar:
 501       case scalar_to_vec:
 502       case cond_branch_not_taken:
 503       case vec_perm:
 504         return 1;
 505
 506       case unaligned_load:
 507       case unaligned_store:
 508         return 2;
 509
 510       case cond_branch_taken:
 511         return 3;
 512
 513       default:
 514         gcc_unreachable ();
 515     }
 516 }
 517
 518 /* Reciprocal.  */
 519
 520 tree
 521 default_builtin_reciprocal (unsigned int fn ATTRIBUTE_UNUSED,
 522                             bool md_fn ATTRIBUTE_UNUSED,
 523                             bool sqrt ATTRIBUTE_UNUSED)
 524 {
 525   return NULL_TREE;
 526 }
 527
 528 bool
 529 hook_bool_CUMULATIVE_ARGS_mode_tree_bool_false (
 530         CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
 531         enum machine_mode mode ATTRIBUTE_UNUSED,
 532         const_tree type ATTRIBUTE_UNUSED, bool named ATTRIBUTE_UNUSED)
 533 {
 534   return false;
 535 }
 536
 537 bool
 538 hook_bool_CUMULATIVE_ARGS_mode_tree_bool_true (
 539         CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
 540         enum machine_mode mode ATTRIBUTE_UNUSED,
 541         const_tree type ATTRIBUTE_UNUSED, bool named ATTRIBUTE_UNUSED)
 542 {
 543   return true;
 544 }
 545
 546 int
 547 hook_int_CUMULATIVE_ARGS_mode_tree_bool_0 (
 548         CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
 549         enum machine_mode mode ATTRIBUTE_UNUSED,
 550         tree type ATTRIBUTE_UNUSED, bool named ATTRIBUTE_UNUSED)
 551 {
 552   return 0;
 553 }
 554
 555 void
 556 default_function_arg_advance (CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
 557                               enum machine_mode mode ATTRIBUTE_UNUSED,
 558                               const_tree type ATTRIBUTE_UNUSED,
 559                               bool named ATTRIBUTE_UNUSED)
 560 {
 561 #ifdef FUNCTION_ARG_ADVANCE
 562   CUMULATIVE_ARGS args = *ca;
 563   FUNCTION_ARG_ADVANCE (args, mode, CONST_CAST_TREE (type), named);
 564   *ca = args;
 565 #else
 566   gcc_unreachable ();
 567 #endif
 568 }
 569
 570 rtx
 571 default_function_arg (const CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
 572                       enum machine_mode mode ATTRIBUTE_UNUSED,
 573                       const_tree type ATTRIBUTE_UNUSED,
 574                       bool named ATTRIBUTE_UNUSED)
 575 {
 576 #ifdef FUNCTION_ARG
 577   return FUNCTION_ARG (*(CONST_CAST (CUMULATIVE_ARGS *, ca)), mode,
 578                        CONST_CAST_TREE (type), named);
 579 #else
 580   gcc_unreachable ();
 581 #endif
 582 }
 583
 584 rtx
 585 default_function_incoming_arg (const 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 (*(CONST_CAST (CUMULATIVE_ARGS *, ca)), mode,
 592                                 CONST_CAST_TREE (type), named);
 593 #else
 594   gcc_unreachable ();
 595 #endif
 596 }
 597
 598 void
 599 hook_void_bitmap (bitmap regs ATTRIBUTE_UNUSED)
 600 {
 601 }
 602
 603 const char *
 604 hook_invalid_arg_for_unprototyped_fn (
 605         const_tree typelist ATTRIBUTE_UNUSED,
 606         const_tree funcdecl ATTRIBUTE_UNUSED,
 607         const_tree val ATTRIBUTE_UNUSED)
 608 {
 609   return NULL;
 610 }
 611
 612 /* Initialize the stack protection decls.  */
 613
 614 /* Stack protection related decls living in libgcc.  */
 615 static GTY(()) tree stack_chk_guard_decl;
 616
 617 tree
 618 default_stack_protect_guard (void)
 619 {
 620   tree t = stack_chk_guard_decl;
 621
 622   if (t == NULL)
 623     {
 624       rtx x;
 625
 626       t = build_decl (UNKNOWN_LOCATION,
 627                       VAR_DECL, get_identifier ("__stack_chk_guard"),
 628                       ptr_type_node);
 629       TREE_STATIC (t) = 1;
 630       TREE_PUBLIC (t) = 1;
 631       DECL_EXTERNAL (t) = 1;
 632       TREE_USED (t) = 1;
 633       TREE_THIS_VOLATILE (t) = 1;
 634       DECL_ARTIFICIAL (t) = 1;
 635       DECL_IGNORED_P (t) = 1;
 636
 637       /* Do not share RTL as the declaration is visible outside of
 638          current function.  */
 639       x = DECL_RTL (t);
 640       RTX_FLAG (x, used) = 1;
 641
 642       stack_chk_guard_decl = t;
 643     }
 644
 645   return t;
 646 }
 647
 648 static GTY(()) tree stack_chk_fail_decl;
 649
 650 tree
 651 default_external_stack_protect_fail (void)
 652 {
 653   tree t = stack_chk_fail_decl;
 654
 655   if (t == NULL_TREE)
 656     {
 657       t = build_function_type_list (void_type_node, NULL_TREE);
 658       t = build_decl (UNKNOWN_LOCATION,
 659                       FUNCTION_DECL, get_identifier ("__stack_chk_fail"), t);
 660       TREE_STATIC (t) = 1;
 661       TREE_PUBLIC (t) = 1;
 662       DECL_EXTERNAL (t) = 1;
 663       TREE_USED (t) = 1;
 664       TREE_THIS_VOLATILE (t) = 1;
 665       TREE_NOTHROW (t) = 1;
 666       DECL_ARTIFICIAL (t) = 1;
 667       DECL_IGNORED_P (t) = 1;
 668       DECL_VISIBILITY (t) = VISIBILITY_DEFAULT;
 669       DECL_VISIBILITY_SPECIFIED (t) = 1;
 670
 671       stack_chk_fail_decl = t;
 672     }
 673
 674   return build_call_expr (t, 0);
 675 }
 676
 677 tree
 678 default_hidden_stack_protect_fail (void)
 679 {
 680 #ifndef HAVE_GAS_HIDDEN
 681   return default_external_stack_protect_fail ();
 682 #else
 683   tree t = stack_chk_fail_decl;
 684
 685   if (!flag_pic)
 686     return default_external_stack_protect_fail ();
 687
 688   if (t == NULL_TREE)
 689     {
 690       t = build_function_type_list (void_type_node, NULL_TREE);
 691       t = build_decl (UNKNOWN_LOCATION, FUNCTION_DECL,
 692                       get_identifier ("__stack_chk_fail_local"), 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_SPECIFIED (t) = 1;
 702       DECL_VISIBILITY (t) = VISIBILITY_HIDDEN;
 703
 704       stack_chk_fail_decl = t;
 705     }
 706
 707   return build_call_expr (t, 0);
 708 #endif
 709 }
 710
 711 bool
 712 hook_bool_const_rtx_commutative_p (const_rtx x,
 713                                    int outer_code ATTRIBUTE_UNUSED)
 714 {
 715   return COMMUTATIVE_P (x);
 716 }
 717
 718 rtx
 719 default_function_value (const_tree ret_type ATTRIBUTE_UNUSED,
 720                         const_tree fn_decl_or_type,
 721                         bool outgoing ATTRIBUTE_UNUSED)
 722 {
 723   /* The old interface doesn't handle receiving the function type.  */
 724   if (fn_decl_or_type
 725       && !DECL_P (fn_decl_or_type))
 726     fn_decl_or_type = NULL;
 727
 728 #ifdef FUNCTION_VALUE
 729   return FUNCTION_VALUE (ret_type, fn_decl_or_type);
 730 #else
 731   gcc_unreachable ();
 732 #endif
 733 }
 734
 735 rtx
 736 default_libcall_value (enum machine_mode mode ATTRIBUTE_UNUSED,
 737                        const_rtx fun ATTRIBUTE_UNUSED)
 738 {
 739 #ifdef LIBCALL_VALUE
 740   return LIBCALL_VALUE (mode);
 741 #else
 742   gcc_unreachable ();
 743 #endif
 744 }
 745
 746 /* The default hook for TARGET_FUNCTION_VALUE_REGNO_P.  */
 747
 748 bool
 749 default_function_value_regno_p (const unsigned int regno ATTRIBUTE_UNUSED)
 750 {
 751 #ifdef FUNCTION_VALUE_REGNO_P
 752   return FUNCTION_VALUE_REGNO_P (regno);
 753 #else
 754   gcc_unreachable ();
 755 #endif
 756 }
 757
 758 rtx
 759 default_internal_arg_pointer (void)
 760 {
 761   /* If the reg that the virtual arg pointer will be translated into is
 762      not a fixed reg or is the stack pointer, make a copy of the virtual
 763      arg pointer, and address parms via the copy.  The frame pointer is
 764      considered fixed even though it is not marked as such.  */
 765   if ((ARG_POINTER_REGNUM == STACK_POINTER_REGNUM
 766        || ! (fixed_regs[ARG_POINTER_REGNUM]
 767              || ARG_POINTER_REGNUM == FRAME_POINTER_REGNUM)))
 768     return copy_to_reg (virtual_incoming_args_rtx);
 769   else
 770     return virtual_incoming_args_rtx;
 771 }
 772
 773 rtx
 774 default_static_chain (const_tree fndecl, bool incoming_p)
 775 {
 776   if (!DECL_STATIC_CHAIN (fndecl))
 777     return NULL;
 778
 779   if (incoming_p)
 780     {
 781 #ifdef STATIC_CHAIN_INCOMING_REGNUM
 782       return gen_rtx_REG (Pmode, STATIC_CHAIN_INCOMING_REGNUM);
 783 #endif
 784     }
 785
 786 #ifdef STATIC_CHAIN_REGNUM
 787   return gen_rtx_REG (Pmode, STATIC_CHAIN_REGNUM);
 788 #endif
 789
 790   {
 791     static bool issued_error;
 792     if (!issued_error)
 793       {
 794         issued_error = true;
 795         sorry ("nested functions not supported on this target");
 796       }
 797
 798     /* It really doesn't matter what we return here, so long at it
 799        doesn't cause the rest of the compiler to crash.  */
 800     return gen_rtx_MEM (Pmode, stack_pointer_rtx);
 801   }
 802 }
 803
 804 void
 805 default_trampoline_init (rtx ARG_UNUSED (m_tramp), tree ARG_UNUSED (t_func),
 806                          rtx ARG_UNUSED (r_chain))
 807 {
 808   sorry ("nested function trampolines not supported on this target");
 809 }
 810
 811 int
 812 default_return_pops_args (tree fundecl ATTRIBUTE_UNUSED,
 813                           tree funtype ATTRIBUTE_UNUSED,
 814                           int size ATTRIBUTE_UNUSED)
 815 {
 816   return 0;
 817 }
 818
 819 reg_class_t
 820 default_branch_target_register_class (void)
 821 {
 822   return NO_REGS;
 823 }
 824
 825 #ifdef IRA_COVER_CLASSES
 826 const reg_class_t *
 827 default_ira_cover_classes (void)
 828 {
 829   static reg_class_t classes[] = IRA_COVER_CLASSES;
 830   return classes;
 831 }
 832 #endif
 833
 834 reg_class_t
 835 default_secondary_reload (bool in_p ATTRIBUTE_UNUSED, rtx x ATTRIBUTE_UNUSED,
 836                           reg_class_t reload_class_i ATTRIBUTE_UNUSED,
 837                           enum machine_mode reload_mode ATTRIBUTE_UNUSED,
 838                           secondary_reload_info *sri)
 839 {
 840   enum reg_class rclass = NO_REGS;
 841   enum reg_class reload_class = (enum reg_class) reload_class_i;
 842
 843   if (sri->prev_sri && sri->prev_sri->t_icode != CODE_FOR_nothing)
 844     {
 845       sri->icode = sri->prev_sri->t_icode;
 846       return NO_REGS;
 847     }
 848 #ifdef SECONDARY_INPUT_RELOAD_CLASS
 849   if (in_p)
 850     rclass = SECONDARY_INPUT_RELOAD_CLASS (reload_class, reload_mode, x);
 851 #endif
 852 #ifdef SECONDARY_OUTPUT_RELOAD_CLASS
 853   if (! in_p)
 854     rclass = SECONDARY_OUTPUT_RELOAD_CLASS (reload_class, reload_mode, x);
 855 #endif
 856   if (rclass != NO_REGS)
 857     {
 858       enum insn_code icode
 859         = direct_optab_handler (in_p ? reload_in_optab : reload_out_optab,
 860                                 reload_mode);
 861
 862       if (icode != CODE_FOR_nothing
 863           && insn_data[(int) icode].operand[in_p].predicate
 864           && ! insn_data[(int) icode].operand[in_p].predicate (x, reload_mode))
 865         icode = CODE_FOR_nothing;
 866       else if (icode != CODE_FOR_nothing)
 867         {
 868           const char *insn_constraint, *scratch_constraint;
 869           char insn_letter, scratch_letter;
 870           enum reg_class insn_class, scratch_class;
 871
 872           gcc_assert (insn_data[(int) icode].n_operands == 3);
 873           insn_constraint = insn_data[(int) icode].operand[!in_p].constraint;
 874           if (!*insn_constraint)
 875             insn_class = ALL_REGS;
 876           else
 877             {
 878               if (in_p)
 879                 {
 880                   gcc_assert (*insn_constraint == '=');
 881                   insn_constraint++;
 882                 }
 883               insn_letter = *insn_constraint;
 884               insn_class
 885                 = (insn_letter == 'r' ? GENERAL_REGS
 886                    : REG_CLASS_FROM_CONSTRAINT ((unsigned char) insn_letter,
 887                                                 insn_constraint));
 888               gcc_assert (insn_class != NO_REGS);
 889             }
 890
 891           scratch_constraint = insn_data[(int) icode].operand[2].constraint;
 892           /* The scratch register's constraint must start with "=&",
 893              except for an input reload, where only "=" is necessary,
 894              and where it might be beneficial to re-use registers from
 895              the input.  */
 896           gcc_assert (scratch_constraint[0] == '='
 897                       && (in_p || scratch_constraint[1] == '&'));
 898           scratch_constraint++;
 899           if (*scratch_constraint == '&')
 900             scratch_constraint++;
 901           scratch_letter = *scratch_constraint;
 902           scratch_class
 903             = (scratch_letter == 'r' ? GENERAL_REGS
 904                : REG_CLASS_FROM_CONSTRAINT ((unsigned char) scratch_letter,
 905                                             scratch_constraint));
 906
 907           if (reg_class_subset_p (reload_class, insn_class))
 908             {
 909               gcc_assert (scratch_class == rclass);
 910               rclass = NO_REGS;
 911             }
 912           else
 913             rclass = insn_class;
 914
 915         }
 916       if (rclass == NO_REGS)
 917         sri->icode = icode;
 918       else
 919         sri->t_icode = icode;
 920     }
 921   return rclass;
 922 }
 923
 924 void
 925 default_target_option_override (void)
 926 {
 927 #ifdef OVERRIDE_OPTIONS
 928   OVERRIDE_OPTIONS;
 929 #endif
 930 }
 931
 932 bool
 933 default_handle_c_option (size_t code ATTRIBUTE_UNUSED,
 934                          const char *arg ATTRIBUTE_UNUSED,
 935                          int value ATTRIBUTE_UNUSED)
 936 {
 937   return false;
 938 }
 939
 940 /* By default, if flag_pic is true, then neither local nor global relocs
 941    should be placed in readonly memory.  */
 942
 943 int
 944 default_reloc_rw_mask (void)
 945 {
 946   return flag_pic ? 3 : 0;
 947 }
 948
 949 /* By default, do no modification. */
 950 tree default_mangle_decl_assembler_name (tree decl ATTRIBUTE_UNUSED,
 951                                          tree id)
 952 {
 953    return id;
 954 }
 955
 956 bool
 957 default_builtin_vector_alignment_reachable (const_tree type, bool is_packed)
 958 {
 959   if (is_packed)
 960     return false;
 961
 962   /* Assuming that types whose size is > pointer-size are not guaranteed to be
 963      naturally aligned.  */
 964   if (tree_int_cst_compare (TYPE_SIZE (type), bitsize_int (POINTER_SIZE)) > 0)
 965     return false;
 966
 967   /* Assuming that types whose size is <= pointer-size
 968      are naturally aligned.  */
 969   return true;
 970 }
 971
 972 /* By default, assume that a target supports any factor of misalignment
 973    memory access if it supports movmisalign patten.
 974    is_packed is true if the memory access is defined in a packed struct.  */
 975 bool
 976 default_builtin_support_vector_misalignment (enum machine_mode mode,
 977                                              const_tree type
 978                                              ATTRIBUTE_UNUSED,
 979                                              int misalignment
 980                                              ATTRIBUTE_UNUSED,
 981                                              bool is_packed
 982                                              ATTRIBUTE_UNUSED)
 983 {
 984   if (optab_handler (movmisalign_optab, mode) != CODE_FOR_nothing)
 985     return true;
 986   return false;
 987 }
 988
 989 /* Determine whether or not a pointer mode is valid. Assume defaults
 990    of ptr_mode or Pmode - can be overridden.  */
 991 bool
 992 default_valid_pointer_mode (enum machine_mode mode)
 993 {
 994   return (mode == ptr_mode || mode == Pmode);
 995 }
 996
 997 /* Return the mode for a pointer to a given ADDRSPACE, defaulting to ptr_mode
 998    for the generic address space only.  */
 999
1000 enum machine_mode
1001 default_addr_space_pointer_mode (addr_space_t addrspace ATTRIBUTE_UNUSED)
1002 {
1003   gcc_assert (ADDR_SPACE_GENERIC_P (addrspace));
1004   return ptr_mode;
1005 }
1006
1007 /* Return the mode for an address in a given ADDRSPACE, defaulting to Pmode
1008    for the generic address space only.  */
1009
1010 enum machine_mode
1011 default_addr_space_address_mode (addr_space_t addrspace ATTRIBUTE_UNUSED)
1012 {
1013   gcc_assert (ADDR_SPACE_GENERIC_P (addrspace));
1014   return Pmode;
1015 }
1016
1017 /* Named address space version of valid_pointer_mode.  */
1018
1019 bool
1020 default_addr_space_valid_pointer_mode (enum machine_mode mode, addr_space_t as)
1021 {
1022   if (!ADDR_SPACE_GENERIC_P (as))
1023     return (mode == targetm.addr_space.pointer_mode (as)
1024             || mode == targetm.addr_space.address_mode (as));
1025
1026   return targetm.valid_pointer_mode (mode);
1027 }
1028
1029 /* Some places still assume that all pointer or address modes are the
1030    standard Pmode and ptr_mode.  These optimizations become invalid if
1031    the target actually supports multiple different modes.  For now,
1032    we disable such optimizations on such targets, using this function.  */
1033
1034 bool
1035 target_default_pointer_address_modes_p (void)
1036 {
1037   if (targetm.addr_space.address_mode != default_addr_space_address_mode)
1038     return false;
1039   if (targetm.addr_space.pointer_mode != default_addr_space_pointer_mode)
1040     return false;
1041
1042   return true;
1043 }
1044
1045 /* Named address space version of legitimate_address_p.  */
1046
1047 bool
1048 default_addr_space_legitimate_address_p (enum machine_mode mode, rtx mem,
1049                                          bool strict, addr_space_t as)
1050 {
1051   if (!ADDR_SPACE_GENERIC_P (as))
1052     gcc_unreachable ();
1053
1054   return targetm.legitimate_address_p (mode, mem, strict);
1055 }
1056
1057 /* Named address space version of LEGITIMIZE_ADDRESS.  */
1058
1059 rtx
1060 default_addr_space_legitimize_address (rtx x, rtx oldx,
1061                                        enum machine_mode mode, addr_space_t as)
1062 {
1063   if (!ADDR_SPACE_GENERIC_P (as))
1064     return x;
1065
1066   return targetm.legitimize_address (x, oldx, mode);
1067 }
1068
1069 /* The default hook for determining if one named address space is a subset of
1070    another and to return which address space to use as the common address
1071    space.  */
1072
1073 bool
1074 default_addr_space_subset_p (addr_space_t subset, addr_space_t superset)
1075 {
1076   return (subset == superset);
1077 }
1078
1079 /* The default hook for TARGET_ADDR_SPACE_CONVERT. This hook should never be
1080    called for targets with only a generic address space.  */
1081
1082 rtx
1083 default_addr_space_convert (rtx op ATTRIBUTE_UNUSED,
1084                             tree from_type ATTRIBUTE_UNUSED,
1085                             tree to_type ATTRIBUTE_UNUSED)
1086 {
1087   gcc_unreachable ();
1088 }
1089
1090 bool
1091 default_hard_regno_scratch_ok (unsigned int regno ATTRIBUTE_UNUSED)
1092 {
1093   return true;
1094 }
1095
1096 /* The default implementation of TARGET_MODE_DEPENDENT_ADDRESS_P.  */
1097
1098 bool
1099 default_mode_dependent_address_p (const_rtx addr ATTRIBUTE_UNUSED)
1100 {
1101 #ifdef GO_IF_MODE_DEPENDENT_ADDRESS
1102
1103   GO_IF_MODE_DEPENDENT_ADDRESS (CONST_CAST_RTX (addr), win);
1104   return false;
1105   /* Label `win' might (not) be used via GO_IF_MODE_DEPENDENT_ADDRESS.  */
1106  win: ATTRIBUTE_UNUSED_LABEL
1107   return true;
1108
1109 #else
1110
1111   return false;
1112
1113 #endif
1114 }
1115
1116 bool
1117 default_target_option_valid_attribute_p (tree ARG_UNUSED (fndecl),
1118                                          tree ARG_UNUSED (name),
1119                                          tree ARG_UNUSED (args),
1120                                          int ARG_UNUSED (flags))
1121 {
1122   warning (OPT_Wattributes,
1123            "target attribute is not supported on this machine");
1124
1125   return false;
1126 }
1127
1128 bool
1129 default_target_option_pragma_parse (tree ARG_UNUSED (args),
1130                                     tree ARG_UNUSED (pop_target))
1131 {
1132   warning (OPT_Wpragmas,
1133            "#pragma GCC target is not supported for this machine");
1134
1135   return false;
1136 }
1137
1138 bool
1139 default_target_can_inline_p (tree caller, tree callee)
1140 {
1141   bool ret = false;
1142   tree callee_opts = DECL_FUNCTION_SPECIFIC_TARGET (callee);
1143   tree caller_opts = DECL_FUNCTION_SPECIFIC_TARGET (caller);
1144
1145   /* If callee has no option attributes, then it is ok to inline */
1146   if (!callee_opts)
1147     ret = true;
1148
1149   /* If caller has no option attributes, but callee does then it is not ok to
1150      inline */
1151   else if (!caller_opts)
1152     ret = false;
1153
1154   /* If both caller and callee have attributes, assume that if the pointer is
1155      different, the the two functions have different target options since
1156      build_target_option_node uses a hash table for the options.  */
1157   else
1158     ret = (callee_opts == caller_opts);
1159
1160   return ret;
1161 }
1162
1163 #ifndef HAVE_casesi
1164 # define HAVE_casesi 0
1165 #endif
1166
1167 /* If the machine does not have a case insn that compares the bounds,
1168    this means extra overhead for dispatch tables, which raises the
1169    threshold for using them.  */
1170
1171 unsigned int default_case_values_threshold (void)
1172 {
1173   return (HAVE_casesi ? 4 : 5);
1174 }
1175
1176 bool
1177 default_have_conditional_execution (void)
1178 {
1179 #ifdef HAVE_conditional_execution
1180   return HAVE_conditional_execution;
1181 #else
1182   return false;
1183 #endif
1184 }
1185
1186 /* Compute cost of moving registers to/from memory.  */
1187
1188 int
1189 default_memory_move_cost (enum machine_mode mode ATTRIBUTE_UNUSED,
1190                           reg_class_t rclass ATTRIBUTE_UNUSED,
1191                           bool in ATTRIBUTE_UNUSED)
1192 {
1193 #ifndef MEMORY_MOVE_COST
1194     return (4 + memory_move_secondary_cost (mode, (enum reg_class) rclass, in));
1195 #else
1196     return MEMORY_MOVE_COST (mode, (enum reg_class) rclass, in);
1197 #endif
1198 }
1199
1200 /* Compute cost of moving data from a register of class FROM to one of
1201    TO, using MODE.  */
1202
1203 int
1204 default_register_move_cost (enum machine_mode mode ATTRIBUTE_UNUSED,
1205                             reg_class_t from ATTRIBUTE_UNUSED,
1206                             reg_class_t to ATTRIBUTE_UNUSED)
1207 {
1208 #ifndef REGISTER_MOVE_COST
1209   return 2;
1210 #else
1211   return REGISTER_MOVE_COST (mode, (enum reg_class) from, (enum reg_class) to);
1212 #endif
1213 }
1214
1215 bool
1216 default_profile_before_prologue (void)
1217 {
1218 #ifdef PROFILE_BEFORE_PROLOGUE
1219   return true;
1220 #else
1221   return false;
1222 #endif
1223 }
1224
1225 #include "gt-targhooks.h"