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 (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 (*ca, mode, CONST_CAST_TREE (type), named);
 578 #else
 579   gcc_unreachable ();
 580 #endif
 581 }
 582
 583 rtx
 584 default_function_incoming_arg (CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
 585                                enum machine_mode mode ATTRIBUTE_UNUSED,
 586                                const_tree type ATTRIBUTE_UNUSED,
 587                                bool named ATTRIBUTE_UNUSED)
 588 {
 589 #ifdef FUNCTION_INCOMING_ARG
 590   return FUNCTION_INCOMING_ARG (*ca, mode, CONST_CAST_TREE (type), named);
 591 #else
 592   gcc_unreachable ();
 593 #endif
 594 }
 595
 596 void
 597 hook_void_bitmap (bitmap regs ATTRIBUTE_UNUSED)
 598 {
 599 }
 600
 601 const char *
 602 hook_invalid_arg_for_unprototyped_fn (
 603         const_tree typelist ATTRIBUTE_UNUSED,
 604         const_tree funcdecl ATTRIBUTE_UNUSED,
 605         const_tree val ATTRIBUTE_UNUSED)
 606 {
 607   return NULL;
 608 }
 609
 610 /* Initialize the stack protection decls.  */
 611
 612 /* Stack protection related decls living in libgcc.  */
 613 static GTY(()) tree stack_chk_guard_decl;
 614
 615 tree
 616 default_stack_protect_guard (void)
 617 {
 618   tree t = stack_chk_guard_decl;
 619
 620   if (t == NULL)
 621     {
 622       rtx x;
 623
 624       t = build_decl (UNKNOWN_LOCATION,
 625                       VAR_DECL, get_identifier ("__stack_chk_guard"),
 626                       ptr_type_node);
 627       TREE_STATIC (t) = 1;
 628       TREE_PUBLIC (t) = 1;
 629       DECL_EXTERNAL (t) = 1;
 630       TREE_USED (t) = 1;
 631       TREE_THIS_VOLATILE (t) = 1;
 632       DECL_ARTIFICIAL (t) = 1;
 633       DECL_IGNORED_P (t) = 1;
 634
 635       /* Do not share RTL as the declaration is visible outside of
 636          current function.  */
 637       x = DECL_RTL (t);
 638       RTX_FLAG (x, used) = 1;
 639
 640       stack_chk_guard_decl = t;
 641     }
 642
 643   return t;
 644 }
 645
 646 static GTY(()) tree stack_chk_fail_decl;
 647
 648 tree
 649 default_external_stack_protect_fail (void)
 650 {
 651   tree t = stack_chk_fail_decl;
 652
 653   if (t == NULL_TREE)
 654     {
 655       t = build_function_type_list (void_type_node, NULL_TREE);
 656       t = build_decl (UNKNOWN_LOCATION,
 657                       FUNCTION_DECL, get_identifier ("__stack_chk_fail"), t);
 658       TREE_STATIC (t) = 1;
 659       TREE_PUBLIC (t) = 1;
 660       DECL_EXTERNAL (t) = 1;
 661       TREE_USED (t) = 1;
 662       TREE_THIS_VOLATILE (t) = 1;
 663       TREE_NOTHROW (t) = 1;
 664       DECL_ARTIFICIAL (t) = 1;
 665       DECL_IGNORED_P (t) = 1;
 666       DECL_VISIBILITY (t) = VISIBILITY_DEFAULT;
 667       DECL_VISIBILITY_SPECIFIED (t) = 1;
 668
 669       stack_chk_fail_decl = t;
 670     }
 671
 672   return build_call_expr (t, 0);
 673 }
 674
 675 tree
 676 default_hidden_stack_protect_fail (void)
 677 {
 678 #ifndef HAVE_GAS_HIDDEN
 679   return default_external_stack_protect_fail ();
 680 #else
 681   tree t = stack_chk_fail_decl;
 682
 683   if (!flag_pic)
 684     return default_external_stack_protect_fail ();
 685
 686   if (t == NULL_TREE)
 687     {
 688       t = build_function_type_list (void_type_node, NULL_TREE);
 689       t = build_decl (UNKNOWN_LOCATION, FUNCTION_DECL,
 690                       get_identifier ("__stack_chk_fail_local"), t);
 691       TREE_STATIC (t) = 1;
 692       TREE_PUBLIC (t) = 1;
 693       DECL_EXTERNAL (t) = 1;
 694       TREE_USED (t) = 1;
 695       TREE_THIS_VOLATILE (t) = 1;
 696       TREE_NOTHROW (t) = 1;
 697       DECL_ARTIFICIAL (t) = 1;
 698       DECL_IGNORED_P (t) = 1;
 699       DECL_VISIBILITY_SPECIFIED (t) = 1;
 700       DECL_VISIBILITY (t) = VISIBILITY_HIDDEN;
 701
 702       stack_chk_fail_decl = t;
 703     }
 704
 705   return build_call_expr (t, 0);
 706 #endif
 707 }
 708
 709 bool
 710 hook_bool_const_rtx_commutative_p (const_rtx x,
 711                                    int outer_code ATTRIBUTE_UNUSED)
 712 {
 713   return COMMUTATIVE_P (x);
 714 }
 715
 716 rtx
 717 default_function_value (const_tree ret_type ATTRIBUTE_UNUSED,
 718                         const_tree fn_decl_or_type,
 719                         bool outgoing ATTRIBUTE_UNUSED)
 720 {
 721   /* The old interface doesn't handle receiving the function type.  */
 722   if (fn_decl_or_type
 723       && !DECL_P (fn_decl_or_type))
 724     fn_decl_or_type = NULL;
 725
 726 #ifdef FUNCTION_VALUE
 727   return FUNCTION_VALUE (ret_type, fn_decl_or_type);
 728 #else
 729   gcc_unreachable ();
 730 #endif
 731 }
 732
 733 rtx
 734 default_libcall_value (enum machine_mode mode ATTRIBUTE_UNUSED,
 735                        const_rtx fun ATTRIBUTE_UNUSED)
 736 {
 737 #ifdef LIBCALL_VALUE
 738   return LIBCALL_VALUE (mode);
 739 #else
 740   gcc_unreachable ();
 741 #endif
 742 }
 743
 744 /* The default hook for TARGET_FUNCTION_VALUE_REGNO_P.  */
 745
 746 bool
 747 default_function_value_regno_p (const unsigned int regno ATTRIBUTE_UNUSED)
 748 {
 749 #ifdef FUNCTION_VALUE_REGNO_P
 750   return FUNCTION_VALUE_REGNO_P (regno);
 751 #else
 752   gcc_unreachable ();
 753 #endif
 754 }
 755
 756 rtx
 757 default_internal_arg_pointer (void)
 758 {
 759   /* If the reg that the virtual arg pointer will be translated into is
 760      not a fixed reg or is the stack pointer, make a copy of the virtual
 761      arg pointer, and address parms via the copy.  The frame pointer is
 762      considered fixed even though it is not marked as such.  */
 763   if ((ARG_POINTER_REGNUM == STACK_POINTER_REGNUM
 764        || ! (fixed_regs[ARG_POINTER_REGNUM]
 765              || ARG_POINTER_REGNUM == FRAME_POINTER_REGNUM)))
 766     return copy_to_reg (virtual_incoming_args_rtx);
 767   else
 768     return virtual_incoming_args_rtx;
 769 }
 770
 771 rtx
 772 default_static_chain (const_tree fndecl, bool incoming_p)
 773 {
 774   if (!DECL_STATIC_CHAIN (fndecl))
 775     return NULL;
 776
 777   if (incoming_p)
 778     {
 779 #ifdef STATIC_CHAIN_INCOMING_REGNUM
 780       return gen_rtx_REG (Pmode, STATIC_CHAIN_INCOMING_REGNUM);
 781 #endif
 782     }
 783
 784 #ifdef STATIC_CHAIN_REGNUM
 785   return gen_rtx_REG (Pmode, STATIC_CHAIN_REGNUM);
 786 #endif
 787
 788   {
 789     static bool issued_error;
 790     if (!issued_error)
 791       {
 792         issued_error = true;
 793         sorry ("nested functions not supported on this target");
 794       }
 795
 796     /* It really doesn't matter what we return here, so long at it
 797        doesn't cause the rest of the compiler to crash.  */
 798     return gen_rtx_MEM (Pmode, stack_pointer_rtx);
 799   }
 800 }
 801
 802 void
 803 default_trampoline_init (rtx ARG_UNUSED (m_tramp), tree ARG_UNUSED (t_func),
 804                          rtx ARG_UNUSED (r_chain))
 805 {
 806   sorry ("nested function trampolines not supported on this target");
 807 }
 808
 809 int
 810 default_return_pops_args (tree fundecl ATTRIBUTE_UNUSED,
 811                           tree funtype ATTRIBUTE_UNUSED,
 812                           int size ATTRIBUTE_UNUSED)
 813 {
 814   return 0;
 815 }
 816
 817 reg_class_t
 818 default_branch_target_register_class (void)
 819 {
 820   return NO_REGS;
 821 }
 822
 823 #ifdef IRA_COVER_CLASSES
 824 const reg_class_t *
 825 default_ira_cover_classes (void)
 826 {
 827   static reg_class_t classes[] = IRA_COVER_CLASSES;
 828   return classes;
 829 }
 830 #endif
 831
 832 reg_class_t
 833 default_secondary_reload (bool in_p ATTRIBUTE_UNUSED, rtx x ATTRIBUTE_UNUSED,
 834                           reg_class_t reload_class_i ATTRIBUTE_UNUSED,
 835                           enum machine_mode reload_mode ATTRIBUTE_UNUSED,
 836                           secondary_reload_info *sri)
 837 {
 838   enum reg_class rclass = NO_REGS;
 839   enum reg_class reload_class = (enum reg_class) reload_class_i;
 840
 841   if (sri->prev_sri && sri->prev_sri->t_icode != CODE_FOR_nothing)
 842     {
 843       sri->icode = sri->prev_sri->t_icode;
 844       return NO_REGS;
 845     }
 846 #ifdef SECONDARY_INPUT_RELOAD_CLASS
 847   if (in_p)
 848     rclass = SECONDARY_INPUT_RELOAD_CLASS (reload_class, reload_mode, x);
 849 #endif
 850 #ifdef SECONDARY_OUTPUT_RELOAD_CLASS
 851   if (! in_p)
 852     rclass = SECONDARY_OUTPUT_RELOAD_CLASS (reload_class, reload_mode, x);
 853 #endif
 854   if (rclass != NO_REGS)
 855     {
 856       enum insn_code icode
 857         = direct_optab_handler (in_p ? reload_in_optab : reload_out_optab,
 858                                 reload_mode);
 859
 860       if (icode != CODE_FOR_nothing
 861           && insn_data[(int) icode].operand[in_p].predicate
 862           && ! insn_data[(int) icode].operand[in_p].predicate (x, reload_mode))
 863         icode = CODE_FOR_nothing;
 864       else if (icode != CODE_FOR_nothing)
 865         {
 866           const char *insn_constraint, *scratch_constraint;
 867           char insn_letter, scratch_letter;
 868           enum reg_class insn_class, scratch_class;
 869
 870           gcc_assert (insn_data[(int) icode].n_operands == 3);
 871           insn_constraint = insn_data[(int) icode].operand[!in_p].constraint;
 872           if (!*insn_constraint)
 873             insn_class = ALL_REGS;
 874           else
 875             {
 876               if (in_p)
 877                 {
 878                   gcc_assert (*insn_constraint == '=');
 879                   insn_constraint++;
 880                 }
 881               insn_letter = *insn_constraint;
 882               insn_class
 883                 = (insn_letter == 'r' ? GENERAL_REGS
 884                    : REG_CLASS_FROM_CONSTRAINT ((unsigned char) insn_letter,
 885                                                 insn_constraint));
 886               gcc_assert (insn_class != NO_REGS);
 887             }
 888
 889           scratch_constraint = insn_data[(int) icode].operand[2].constraint;
 890           /* The scratch register's constraint must start with "=&",
 891              except for an input reload, where only "=" is necessary,
 892              and where it might be beneficial to re-use registers from
 893              the input.  */
 894           gcc_assert (scratch_constraint[0] == '='
 895                       && (in_p || scratch_constraint[1] == '&'));
 896           scratch_constraint++;
 897           if (*scratch_constraint == '&')
 898             scratch_constraint++;
 899           scratch_letter = *scratch_constraint;
 900           scratch_class
 901             = (scratch_letter == 'r' ? GENERAL_REGS
 902                : REG_CLASS_FROM_CONSTRAINT ((unsigned char) scratch_letter,
 903                                             scratch_constraint));
 904
 905           if (reg_class_subset_p (reload_class, insn_class))
 906             {
 907               gcc_assert (scratch_class == rclass);
 908               rclass = NO_REGS;
 909             }
 910           else
 911             rclass = insn_class;
 912
 913         }
 914       if (rclass == NO_REGS)
 915         sri->icode = icode;
 916       else
 917         sri->t_icode = icode;
 918     }
 919   return rclass;
 920 }
 921
 922 bool
 923 default_handle_c_option (size_t code ATTRIBUTE_UNUSED,
 924                          const char *arg ATTRIBUTE_UNUSED,
 925                          int value ATTRIBUTE_UNUSED)
 926 {
 927   return false;
 928 }
 929
 930 /* By default, if flag_pic is true, then neither local nor global relocs
 931    should be placed in readonly memory.  */
 932
 933 int
 934 default_reloc_rw_mask (void)
 935 {
 936   return flag_pic ? 3 : 0;
 937 }
 938
 939 /* By default, do no modification. */
 940 tree default_mangle_decl_assembler_name (tree decl ATTRIBUTE_UNUSED,
 941                                          tree id)
 942 {
 943    return id;
 944 }
 945
 946 bool
 947 default_builtin_vector_alignment_reachable (const_tree type, bool is_packed)
 948 {
 949   if (is_packed)
 950     return false;
 951
 952   /* Assuming that types whose size is > pointer-size are not guaranteed to be
 953      naturally aligned.  */
 954   if (tree_int_cst_compare (TYPE_SIZE (type), bitsize_int (POINTER_SIZE)) > 0)
 955     return false;
 956
 957   /* Assuming that types whose size is <= pointer-size
 958      are naturally aligned.  */
 959   return true;
 960 }
 961
 962 /* By default, assume that a target supports any factor of misalignment
 963    memory access if it supports movmisalign patten.
 964    is_packed is true if the memory access is defined in a packed struct.  */
 965 bool
 966 default_builtin_support_vector_misalignment (enum machine_mode mode,
 967                                              const_tree type
 968                                              ATTRIBUTE_UNUSED,
 969                                              int misalignment
 970                                              ATTRIBUTE_UNUSED,
 971                                              bool is_packed
 972                                              ATTRIBUTE_UNUSED)
 973 {
 974   if (optab_handler (movmisalign_optab, mode) != CODE_FOR_nothing)
 975     return true;
 976   return false;
 977 }
 978
 979 /* By default, only attempt to parallelize bitwise operations, and
 980    possibly adds/subtracts using bit-twiddling.  */
 981
 982 enum machine_mode
 983 default_preferred_simd_mode (enum machine_mode mode ATTRIBUTE_UNUSED)
 984 {
 985   return word_mode;
 986 }
 987
 988 /* Determine whether or not a pointer mode is valid. Assume defaults
 989    of ptr_mode or Pmode - can be overridden.  */
 990 bool
 991 default_valid_pointer_mode (enum machine_mode mode)
 992 {
 993   return (mode == ptr_mode || mode == Pmode);
 994 }
 995
 996 /* Return the mode for a pointer to a given ADDRSPACE, defaulting to ptr_mode
 997    for the generic address space only.  */
 998
 999 enum machine_mode
1000 default_addr_space_pointer_mode (addr_space_t addrspace ATTRIBUTE_UNUSED)
1001 {
1002   gcc_assert (ADDR_SPACE_GENERIC_P (addrspace));
1003   return ptr_mode;
1004 }
1005
1006 /* Return the mode for an address in a given ADDRSPACE, defaulting to Pmode
1007    for the generic address space only.  */
1008
1009 enum machine_mode
1010 default_addr_space_address_mode (addr_space_t addrspace ATTRIBUTE_UNUSED)
1011 {
1012   gcc_assert (ADDR_SPACE_GENERIC_P (addrspace));
1013   return Pmode;
1014 }
1015
1016 /* Named address space version of valid_pointer_mode.  */
1017
1018 bool
1019 default_addr_space_valid_pointer_mode (enum machine_mode mode, addr_space_t as)
1020 {
1021   if (!ADDR_SPACE_GENERIC_P (as))
1022     return (mode == targetm.addr_space.pointer_mode (as)
1023             || mode == targetm.addr_space.address_mode (as));
1024
1025   return targetm.valid_pointer_mode (mode);
1026 }
1027
1028 /* Some places still assume that all pointer or address modes are the
1029    standard Pmode and ptr_mode.  These optimizations become invalid if
1030    the target actually supports multiple different modes.  For now,
1031    we disable such optimizations on such targets, using this function.  */
1032
1033 bool
1034 target_default_pointer_address_modes_p (void)
1035 {
1036   if (targetm.addr_space.address_mode != default_addr_space_address_mode)
1037     return false;
1038   if (targetm.addr_space.pointer_mode != default_addr_space_pointer_mode)
1039     return false;
1040
1041   return true;
1042 }
1043
1044 /* Named address space version of legitimate_address_p.  */
1045
1046 bool
1047 default_addr_space_legitimate_address_p (enum machine_mode mode, rtx mem,
1048                                          bool strict, addr_space_t as)
1049 {
1050   if (!ADDR_SPACE_GENERIC_P (as))
1051     gcc_unreachable ();
1052
1053   return targetm.legitimate_address_p (mode, mem, strict);
1054 }
1055
1056 /* Named address space version of LEGITIMIZE_ADDRESS.  */
1057
1058 rtx
1059 default_addr_space_legitimize_address (rtx x, rtx oldx,
1060                                        enum machine_mode mode, addr_space_t as)
1061 {
1062   if (!ADDR_SPACE_GENERIC_P (as))
1063     return x;
1064
1065   return targetm.legitimize_address (x, oldx, mode);
1066 }
1067
1068 /* The default hook for determining if one named address space is a subset of
1069    another and to return which address space to use as the common address
1070    space.  */
1071
1072 bool
1073 default_addr_space_subset_p (addr_space_t subset, addr_space_t superset)
1074 {
1075   return (subset == superset);
1076 }
1077
1078 /* The default hook for TARGET_ADDR_SPACE_CONVERT. This hook should never be
1079    called for targets with only a generic address space.  */
1080
1081 rtx
1082 default_addr_space_convert (rtx op ATTRIBUTE_UNUSED,
1083                             tree from_type ATTRIBUTE_UNUSED,
1084                             tree to_type ATTRIBUTE_UNUSED)
1085 {
1086   gcc_unreachable ();
1087 }
1088
1089 bool
1090 default_hard_regno_scratch_ok (unsigned int regno ATTRIBUTE_UNUSED)
1091 {
1092   return true;
1093 }
1094
1095 /* The default implementation of TARGET_MODE_DEPENDENT_ADDRESS_P.  */
1096
1097 bool
1098 default_mode_dependent_address_p (const_rtx addr ATTRIBUTE_UNUSED)
1099 {
1100 #ifdef GO_IF_MODE_DEPENDENT_ADDRESS
1101
1102   GO_IF_MODE_DEPENDENT_ADDRESS (CONST_CAST_RTX (addr), win);
1103   return false;
1104   /* Label `win' might (not) be used via GO_IF_MODE_DEPENDENT_ADDRESS.  */
1105  win: ATTRIBUTE_UNUSED_LABEL
1106   return true;
1107
1108 #else
1109
1110   return false;
1111
1112 #endif
1113 }
1114
1115 bool
1116 default_target_option_valid_attribute_p (tree ARG_UNUSED (fndecl),
1117                                          tree ARG_UNUSED (name),
1118                                          tree ARG_UNUSED (args),
1119                                          int ARG_UNUSED (flags))
1120 {
1121   warning (OPT_Wattributes,
1122            "target attribute is not supported on this machine");
1123
1124   return false;
1125 }
1126
1127 bool
1128 default_target_option_pragma_parse (tree ARG_UNUSED (args),
1129                                     tree ARG_UNUSED (pop_target))
1130 {
1131   warning (OPT_Wpragmas,
1132            "#pragma GCC target is not supported for this machine");
1133
1134   return false;
1135 }
1136
1137 bool
1138 default_target_can_inline_p (tree caller, tree callee)
1139 {
1140   bool ret = false;
1141   tree callee_opts = DECL_FUNCTION_SPECIFIC_TARGET (callee);
1142   tree caller_opts = DECL_FUNCTION_SPECIFIC_TARGET (caller);
1143
1144   /* If callee has no option attributes, then it is ok to inline */
1145   if (!callee_opts)
1146     ret = true;
1147
1148   /* If caller has no option attributes, but callee does then it is not ok to
1149      inline */
1150   else if (!caller_opts)
1151     ret = false;
1152
1153   /* If both caller and callee have attributes, assume that if the pointer is
1154      different, the the two functions have different target options since
1155      build_target_option_node uses a hash table for the options.  */
1156   else
1157     ret = (callee_opts == caller_opts);
1158
1159   return ret;
1160 }
1161
1162 #ifndef HAVE_casesi
1163 # define HAVE_casesi 0
1164 #endif
1165
1166 /* If the machine does not have a case insn that compares the bounds,
1167    this means extra overhead for dispatch tables, which raises the
1168    threshold for using them.  */
1169
1170 unsigned int default_case_values_threshold (void)
1171 {
1172   return (HAVE_casesi ? 4 : 5);
1173 }
1174
1175 bool
1176 default_have_conditional_execution (void)
1177 {
1178 #ifdef HAVE_conditional_execution
1179   return HAVE_conditional_execution;
1180 #else
1181   return false;
1182 #endif
1183 }
1184
1185 /* Compute cost of moving registers to/from memory.  */
1186
1187 int
1188 default_memory_move_cost (enum machine_mode mode ATTRIBUTE_UNUSED,
1189                           reg_class_t rclass ATTRIBUTE_UNUSED,
1190                           bool in ATTRIBUTE_UNUSED)
1191 {
1192 #ifndef MEMORY_MOVE_COST
1193     return (4 + memory_move_secondary_cost (mode, (enum reg_class) rclass, in));
1194 #else
1195     return MEMORY_MOVE_COST (mode, (enum reg_class) rclass, in);
1196 #endif
1197 }
1198
1199 /* Compute cost of moving data from a register of class FROM to one of
1200    TO, using MODE.  */
1201
1202 int
1203 default_register_move_cost (enum machine_mode mode ATTRIBUTE_UNUSED,
1204                             reg_class_t from ATTRIBUTE_UNUSED,
1205                             reg_class_t to ATTRIBUTE_UNUSED)
1206 {
1207 #ifndef REGISTER_MOVE_COST
1208   return 2;
1209 #else
1210   return REGISTER_MOVE_COST (mode, (enum reg_class) from, (enum reg_class) to);
1211 #endif
1212 }
1213
1214 bool
1215 default_profile_before_prologue (void)
1216 {
1217 #ifdef PROFILE_BEFORE_PROLOGUE
1218   return true;
1219 #else
1220   return false;
1221 #endif
1222 }
1223
1224 /* The default implementation of TARGET_CLASS_LIKELY_SPILLED_P.  */
1225
1226 bool
1227 default_class_likely_spilled_p (reg_class_t rclass)
1228 {
1229   return (reg_class_size[(int) rclass] == 1);
1230 }
1231
1232 /* Determine the debugging unwind mechanism for the target.  */
1233
1234 enum unwind_info_type
1235 default_debug_unwind_info (void)
1236 {
1237   /* If the target wants to force the use of dwarf2 unwind info, let it.  */
1238   /* ??? Change all users to the hook, then poison this.  */
1239 #ifdef DWARF2_FRAME_INFO
1240   if (DWARF2_FRAME_INFO)
1241     return UI_DWARF2;
1242 #endif
1243
1244   /* Otherwise, only turn it on if dwarf2 debugging is enabled.  */
1245 #ifdef DWARF2_DEBUGGING_INFO
1246   if (write_symbols == DWARF2_DEBUG || write_symbols == VMS_AND_DWARF2_DEBUG)
1247     return UI_DWARF2;
1248 #endif
1249
1250   return UI_NONE;
1251 }
1252
1253 /* Determine the exception handling mechanism for the target.  */
1254
1255 enum unwind_info_type
1256 default_except_unwind_info (void)
1257 {
1258   /* ??? Change the one user to the hook, then poison this.  */
1259 #ifdef MUST_USE_SJLJ_EXCEPTIONS
1260   if (MUST_USE_SJLJ_EXCEPTIONS)
1261     return UI_SJLJ;
1262 #endif
1263
1264   /* Obey the configure switch to turn on sjlj exceptions.  */
1265 #ifdef CONFIG_SJLJ_EXCEPTIONS
1266   if (CONFIG_SJLJ_EXCEPTIONS)
1267     return UI_SJLJ;
1268 #endif
1269
1270   /* ??? Change all users to the hook, then poison this.  */
1271 #ifdef DWARF2_UNWIND_INFO
1272   if (DWARF2_UNWIND_INFO)
1273     return UI_DWARF2;
1274 #endif
1275
1276   return UI_SJLJ;
1277 }
1278
1279 /* To be used by targets that force dwarf2 unwind enabled.  */
1280
1281 enum unwind_info_type
1282 dwarf2_except_unwind_info (void)
1283 {
1284   /* Obey the configure switch to turn on sjlj exceptions.  */
1285 #ifdef CONFIG_SJLJ_EXCEPTIONS
1286   if (CONFIG_SJLJ_EXCEPTIONS)
1287     return UI_SJLJ;
1288 #endif
1289
1290   return UI_DWARF2;
1291 }
1292
1293 /* To be used by targets that force sjlj unwind enabled.  */
1294
1295 enum unwind_info_type
1296 sjlj_except_unwind_info (void)
1297 {
1298   return UI_SJLJ;
1299 }
1300
1301 #include "gt-targhooks.h"