gcc/targhooks.c

   1 /* Default target hook functions.
   2    Copyright (C) 2003-2015 Free Software Foundation, Inc.
   3
   4 This file is part of GCC.
   5
   6 GCC is free software; you can redistribute it and/or modify it under
   7 the terms of the GNU General Public License as published by the Free
   8 Software Foundation; either version 3, or (at your option) any later
   9 version.
  10
  11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14 for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GCC; see the file COPYING3.  If not see
  18 <http://www.gnu.org/licenses/>.  */
  19
  20 /* The migration of target macros to target hooks works as follows:
  21
  22    1. Create a target hook that uses the existing target macros to
  23       implement the same functionality.
  24
  25    2. Convert all the MI files to use the hook instead of the macro.
  26
  27    3. Repeat for a majority of the remaining target macros.  This will
  28       take some time.
  29
  30    4. Tell target maintainers to start migrating.
  31
  32    5. Eventually convert the backends to override the hook instead of
  33       defining the macros.  This will take some time too.
  34
  35    6. TBD when, poison the macros.  Unmigrated targets will break at
  36       this point.
  37
  38    Note that we expect steps 1-3 to be done by the people that
  39    understand what the MI does with each macro, and step 5 to be done
  40    by the target maintainers for their respective targets.
  41
  42    Note that steps 1 and 2 don't have to be done together, but no
  43    target can override the new hook until step 2 is complete for it.
  44
  45    Once the macros are poisoned, we will revert to the old migration
  46    rules - migrate the macro, callers, and targets all at once.  This
  47    comment can thus be removed at that point.  */
  48
  49 #include "config.h"
  50 #include "system.h"
  51 #include "coretypes.h"
  52 #include "tm.h"
  53 #include "machmode.h"
  54 #include "rtl.h"
  55 #include "hash-set.h"
  56 #include "vec.h"
  57 #include "double-int.h"
  58 #include "input.h"
  59 #include "alias.h"
  60 #include "symtab.h"
  61 #include "wide-int.h"
  62 #include "inchash.h"
  63 #include "tree.h"
  64 #include "fold-const.h"
  65 #include "stor-layout.h"
  66 #include "varasm.h"
  67 #include "hashtab.h"
  68 #include "hard-reg-set.h"
  69 #include "function.h"
  70 #include "flags.h"
  71 #include "statistics.h"
  72 #include "real.h"
  73 #include "fixed-value.h"
  74 #include "insn-config.h"
  75 #include "expmed.h"
  76 #include "dojump.h"
  77 #include "explow.h"
  78 #include "calls.h"
  79 #include "emit-rtl.h"
  80 #include "stmt.h"
  81 #include "expr.h"
  82 #include "output.h"
  83 #include "diagnostic-core.h"
  84 #include "target.h"
  85 #include "tm_p.h"
  86 #include "target-def.h"
  87 #include "regs.h"
  88 #include "reload.h"
  89 #include "insn-codes.h"
  90 #include "optabs.h"
  91 #include "recog.h"
  92 #include "intl.h"
  93 #include "opts.h"
  94 #include "tree-ssa-alias.h"
  95 #include "gimple-expr.h"
  96 #include "gimplify.h"
  97 #include "stringpool.h"
  98 #include "tree-ssanames.h"
  99
 100
 101 bool
 102 default_legitimate_address_p (machine_mode mode ATTRIBUTE_UNUSED,
 103                               rtx addr ATTRIBUTE_UNUSED,
 104                               bool strict ATTRIBUTE_UNUSED)
 105 {
 106 #ifdef GO_IF_LEGITIMATE_ADDRESS
 107   /* Defer to the old implementation using a goto.  */
 108   if (strict)
 109     return strict_memory_address_p (mode, addr);
 110   else
 111     return memory_address_p (mode, addr);
 112 #else
 113   gcc_unreachable ();
 114 #endif
 115 }
 116
 117 void
 118 default_external_libcall (rtx fun ATTRIBUTE_UNUSED)
 119 {
 120 #ifdef ASM_OUTPUT_EXTERNAL_LIBCALL
 121   ASM_OUTPUT_EXTERNAL_LIBCALL (asm_out_file, fun);
 122 #endif
 123 }
 124
 125 int
 126 default_unspec_may_trap_p (const_rtx x, unsigned flags)
 127 {
 128   int i;
 129
 130   /* Any floating arithmetic may trap.  */
 131   if ((SCALAR_FLOAT_MODE_P (GET_MODE (x)) && flag_trapping_math))
 132     return 1;
 133
 134   for (i = 0; i < XVECLEN (x, 0); ++i)
 135     {
 136       if (may_trap_p_1 (XVECEXP (x, 0, i), flags))
 137         return 1;
 138     }
 139
 140   return 0;
 141 }
 142
 143 machine_mode
 144 default_promote_function_mode (const_tree type ATTRIBUTE_UNUSED,
 145                                machine_mode mode,
 146                                int *punsignedp ATTRIBUTE_UNUSED,
 147                                const_tree funtype ATTRIBUTE_UNUSED,
 148                                int for_return ATTRIBUTE_UNUSED)
 149 {
 150   if (type != NULL_TREE && for_return == 2)
 151     return promote_mode (type, mode, punsignedp);
 152   return mode;
 153 }
 154
 155 machine_mode
 156 default_promote_function_mode_always_promote (const_tree type,
 157                                               machine_mode mode,
 158                                               int *punsignedp,
 159                                               const_tree funtype ATTRIBUTE_UNUSED,
 160                                               int for_return ATTRIBUTE_UNUSED)
 161 {
 162   return promote_mode (type, mode, punsignedp);
 163 }
 164
 165 machine_mode
 166 default_cc_modes_compatible (machine_mode m1, machine_mode m2)
 167 {
 168   if (m1 == m2)
 169     return m1;
 170   return VOIDmode;
 171 }
 172
 173 bool
 174 default_return_in_memory (const_tree type,
 175                           const_tree fntype ATTRIBUTE_UNUSED)
 176 {
 177   return (TYPE_MODE (type) == BLKmode);
 178 }
 179
 180 rtx
 181 default_legitimize_address (rtx x, rtx orig_x ATTRIBUTE_UNUSED,
 182                             machine_mode mode ATTRIBUTE_UNUSED)
 183 {
 184   return x;
 185 }
 186
 187 bool
 188 default_legitimize_address_displacement (rtx *disp ATTRIBUTE_UNUSED,
 189                                          rtx *offset ATTRIBUTE_UNUSED,
 190                                          machine_mode mode ATTRIBUTE_UNUSED)
 191 {
 192   return false;
 193 }
 194
 195 rtx
 196 default_expand_builtin_saveregs (void)
 197 {
 198   error ("__builtin_saveregs not supported by this target");
 199   return const0_rtx;
 200 }
 201
 202 void
 203 default_setup_incoming_varargs (cumulative_args_t ca ATTRIBUTE_UNUSED,
 204                                 machine_mode mode ATTRIBUTE_UNUSED,
 205                                 tree type ATTRIBUTE_UNUSED,
 206                                 int *pretend_arg_size ATTRIBUTE_UNUSED,
 207                                 int second_time ATTRIBUTE_UNUSED)
 208 {
 209 }
 210
 211 /* The default implementation of TARGET_BUILTIN_SETJMP_FRAME_VALUE.  */
 212
 213 rtx
 214 default_builtin_setjmp_frame_value (void)
 215 {
 216   return virtual_stack_vars_rtx;
 217 }
 218
 219 /* Generic hook that takes a CUMULATIVE_ARGS pointer and returns false.  */
 220
 221 bool
 222 hook_bool_CUMULATIVE_ARGS_false (cumulative_args_t ca ATTRIBUTE_UNUSED)
 223 {
 224   return false;
 225 }
 226
 227 bool
 228 default_pretend_outgoing_varargs_named (cumulative_args_t ca ATTRIBUTE_UNUSED)
 229 {
 230   return (targetm.calls.setup_incoming_varargs
 231           != default_setup_incoming_varargs);
 232 }
 233
 234 machine_mode
 235 default_eh_return_filter_mode (void)
 236 {
 237   return targetm.unwind_word_mode ();
 238 }
 239
 240 machine_mode
 241 default_libgcc_cmp_return_mode (void)
 242 {
 243   return word_mode;
 244 }
 245
 246 machine_mode
 247 default_libgcc_shift_count_mode (void)
 248 {
 249   return word_mode;
 250 }
 251
 252 machine_mode
 253 default_unwind_word_mode (void)
 254 {
 255   return word_mode;
 256 }
 257
 258 /* The default implementation of TARGET_SHIFT_TRUNCATION_MASK.  */
 259
 260 unsigned HOST_WIDE_INT
 261 default_shift_truncation_mask (machine_mode mode)
 262 {
 263   return SHIFT_COUNT_TRUNCATED ? GET_MODE_BITSIZE (mode) - 1 : 0;
 264 }
 265
 266 /* The default implementation of TARGET_MIN_DIVISIONS_FOR_RECIP_MUL.  */
 267
 268 unsigned int
 269 default_min_divisions_for_recip_mul (machine_mode mode ATTRIBUTE_UNUSED)
 270 {
 271   return have_insn_for (DIV, mode) ? 3 : 2;
 272 }
 273
 274 /* The default implementation of TARGET_MODE_REP_EXTENDED.  */
 275
 276 int
 277 default_mode_rep_extended (machine_mode mode ATTRIBUTE_UNUSED,
 278                            machine_mode mode_rep ATTRIBUTE_UNUSED)
 279 {
 280   return UNKNOWN;
 281 }
 282
 283 /* Generic hook that takes a CUMULATIVE_ARGS pointer and returns true.  */
 284
 285 bool
 286 hook_bool_CUMULATIVE_ARGS_true (cumulative_args_t a ATTRIBUTE_UNUSED)
 287 {
 288   return true;
 289 }
 290
 291 /* Return machine mode for non-standard suffix
 292    or VOIDmode if non-standard suffixes are unsupported.  */
 293 machine_mode
 294 default_mode_for_suffix (char suffix ATTRIBUTE_UNUSED)
 295 {
 296   return VOIDmode;
 297 }
 298
 299 /* The generic C++ ABI specifies this is a 64-bit value.  */
 300 tree
 301 default_cxx_guard_type (void)
 302 {
 303   return long_long_integer_type_node;
 304 }
 305
 306 /* Returns the size of the cookie to use when allocating an array
 307    whose elements have the indicated TYPE.  Assumes that it is already
 308    known that a cookie is needed.  */
 309
 310 tree
 311 default_cxx_get_cookie_size (tree type)
 312 {
 313   tree cookie_size;
 314
 315   /* We need to allocate an additional max (sizeof (size_t), alignof
 316      (true_type)) bytes.  */
 317   tree sizetype_size;
 318   tree type_align;
 319
 320   sizetype_size = size_in_bytes (sizetype);
 321   type_align = size_int (TYPE_ALIGN_UNIT (type));
 322   if (tree_int_cst_lt (type_align, sizetype_size))
 323     cookie_size = sizetype_size;
 324   else
 325     cookie_size = type_align;
 326
 327   return cookie_size;
 328 }
 329
 330 /* Return true if a parameter must be passed by reference.  This version
 331    of the TARGET_PASS_BY_REFERENCE hook uses just MUST_PASS_IN_STACK.  */
 332
 333 bool
 334 hook_pass_by_reference_must_pass_in_stack (cumulative_args_t c ATTRIBUTE_UNUSED,
 335         machine_mode mode ATTRIBUTE_UNUSED, const_tree type ATTRIBUTE_UNUSED,
 336         bool named_arg ATTRIBUTE_UNUSED)
 337 {
 338   return targetm.calls.must_pass_in_stack (mode, type);
 339 }
 340
 341 /* Return true if a parameter follows callee copies conventions.  This
 342    version of the hook is true for all named arguments.  */
 343
 344 bool
 345 hook_callee_copies_named (cumulative_args_t ca ATTRIBUTE_UNUSED,
 346                           machine_mode mode ATTRIBUTE_UNUSED,
 347                           const_tree type ATTRIBUTE_UNUSED, bool named)
 348 {
 349   return named;
 350 }
 351
 352 /* Emit to STREAM the assembler syntax for insn operand X.  */
 353
 354 void
 355 default_print_operand (FILE *stream ATTRIBUTE_UNUSED, rtx x ATTRIBUTE_UNUSED,
 356                        int code ATTRIBUTE_UNUSED)
 357 {
 358 #ifdef PRINT_OPERAND
 359   PRINT_OPERAND (stream, x, code);
 360 #else
 361   gcc_unreachable ();
 362 #endif
 363 }
 364
 365 /* Emit to STREAM the assembler syntax for an insn operand whose memory
 366    address is X.  */
 367
 368 void
 369 default_print_operand_address (FILE *stream ATTRIBUTE_UNUSED,
 370                                rtx x ATTRIBUTE_UNUSED)
 371 {
 372 #ifdef PRINT_OPERAND_ADDRESS
 373   PRINT_OPERAND_ADDRESS (stream, x);
 374 #else
 375   gcc_unreachable ();
 376 #endif
 377 }
 378
 379 /* Return true if CODE is a valid punctuation character for the
 380    `print_operand' hook.  */
 381
 382 bool
 383 default_print_operand_punct_valid_p (unsigned char code ATTRIBUTE_UNUSED)
 384 {
 385 #ifdef PRINT_OPERAND_PUNCT_VALID_P
 386   return PRINT_OPERAND_PUNCT_VALID_P (code);
 387 #else
 388   return false;
 389 #endif
 390 }
 391
 392 /* The default implementation of TARGET_MANGLE_ASSEMBLER_NAME.  */
 393 tree
 394 default_mangle_assembler_name (const char *name ATTRIBUTE_UNUSED)
 395 {
 396   const char *skipped = name + (*name == '*' ? 1 : 0);
 397   const char *stripped = targetm.strip_name_encoding (skipped);
 398   if (*name != '*' && user_label_prefix[0])
 399     stripped = ACONCAT ((user_label_prefix, stripped, NULL));
 400   return get_identifier (stripped);
 401 }
 402
 403 /* True if MODE is valid for the target.  By "valid", we mean able to
 404    be manipulated in non-trivial ways.  In particular, this means all
 405    the arithmetic is supported.
 406
 407    By default we guess this means that any C type is supported.  If
 408    we can't map the mode back to a type that would be available in C,
 409    then reject it.  Special case, here, is the double-word arithmetic
 410    supported by optabs.c.  */
 411
 412 bool
 413 default_scalar_mode_supported_p (machine_mode mode)
 414 {
 415   int precision = GET_MODE_PRECISION (mode);
 416
 417   switch (GET_MODE_CLASS (mode))
 418     {
 419     case MODE_PARTIAL_INT:
 420     case MODE_INT:
 421       if (precision == CHAR_TYPE_SIZE)
 422         return true;
 423       if (precision == SHORT_TYPE_SIZE)
 424         return true;
 425       if (precision == INT_TYPE_SIZE)
 426         return true;
 427       if (precision == LONG_TYPE_SIZE)
 428         return true;
 429       if (precision == LONG_LONG_TYPE_SIZE)
 430         return true;
 431       if (precision == 2 * BITS_PER_WORD)
 432         return true;
 433       return false;
 434
 435     case MODE_FLOAT:
 436       if (precision == FLOAT_TYPE_SIZE)
 437         return true;
 438       if (precision == DOUBLE_TYPE_SIZE)
 439         return true;
 440       if (precision == LONG_DOUBLE_TYPE_SIZE)
 441         return true;
 442       return false;
 443
 444     case MODE_DECIMAL_FLOAT:
 445     case MODE_FRACT:
 446     case MODE_UFRACT:
 447     case MODE_ACCUM:
 448     case MODE_UACCUM:
 449       return false;
 450
 451     default:
 452       gcc_unreachable ();
 453     }
 454 }
 455
 456 /* Return true if libgcc supports floating-point mode MODE (known to
 457    be supported as a scalar mode).  */
 458
 459 bool
 460 default_libgcc_floating_mode_supported_p (machine_mode mode)
 461 {
 462   switch (mode)
 463     {
 464 #ifdef HAVE_SFmode
 465     case SFmode:
 466 #endif
 467 #ifdef HAVE_DFmode
 468     case DFmode:
 469 #endif
 470 #ifdef HAVE_XFmode
 471     case XFmode:
 472 #endif
 473 #ifdef HAVE_TFmode
 474     case TFmode:
 475 #endif
 476       return true;
 477
 478     default:
 479       return false;
 480     }
 481 }
 482
 483 /* Make some target macros useable by target-independent code.  */
 484 bool
 485 targhook_words_big_endian (void)
 486 {
 487   return !!WORDS_BIG_ENDIAN;
 488 }
 489
 490 bool
 491 targhook_float_words_big_endian (void)
 492 {
 493   return !!FLOAT_WORDS_BIG_ENDIAN;
 494 }
 495
 496 /* True if the target supports floating-point exceptions and rounding
 497    modes.  */
 498
 499 bool
 500 default_float_exceptions_rounding_supported_p (void)
 501 {
 502 #ifdef HAVE_adddf3
 503   return HAVE_adddf3;
 504 #else
 505   return false;
 506 #endif
 507 }
 508
 509 /* True if the target supports decimal floating point.  */
 510
 511 bool
 512 default_decimal_float_supported_p (void)
 513 {
 514   return ENABLE_DECIMAL_FLOAT;
 515 }
 516
 517 /* True if the target supports fixed-point arithmetic.  */
 518
 519 bool
 520 default_fixed_point_supported_p (void)
 521 {
 522   return ENABLE_FIXED_POINT;
 523 }
 524
 525 /* True if the target supports GNU indirect functions.  */
 526
 527 bool
 528 default_has_ifunc_p (void)
 529 {
 530   return HAVE_GNU_INDIRECT_FUNCTION;
 531 }
 532
 533 /* NULL if INSN insn is valid within a low-overhead loop, otherwise returns
 534    an error message.
 535
 536    This function checks whether a given INSN is valid within a low-overhead
 537    loop.  If INSN is invalid it returns the reason for that, otherwise it
 538    returns NULL. A called function may clobber any special registers required
 539    for low-overhead looping. Additionally, some targets (eg, PPC) use the count
 540    register for branch on table instructions. We reject the doloop pattern in
 541    these cases.  */
 542
 543 const char *
 544 default_invalid_within_doloop (const rtx_insn *insn)
 545 {
 546   if (CALL_P (insn))
 547     return "Function call in loop.";
 548
 549   if (tablejump_p (insn, NULL, NULL) || computed_jump_p (insn))
 550     return "Computed branch in the loop.";
 551
 552   return NULL;
 553 }
 554
 555 /* Mapping of builtin functions to vectorized variants.  */
 556
 557 tree
 558 default_builtin_vectorized_function (tree fndecl ATTRIBUTE_UNUSED,
 559                                      tree type_out ATTRIBUTE_UNUSED,
 560                                      tree type_in ATTRIBUTE_UNUSED)
 561 {
 562   return NULL_TREE;
 563 }
 564
 565 /* Vectorized conversion.  */
 566
 567 tree
 568 default_builtin_vectorized_conversion (unsigned int code ATTRIBUTE_UNUSED,
 569                                        tree dest_type ATTRIBUTE_UNUSED,
 570                                        tree src_type ATTRIBUTE_UNUSED)
 571 {
 572   return NULL_TREE;
 573 }
 574
 575 /* Default vectorizer cost model values.  */
 576
 577 int
 578 default_builtin_vectorization_cost (enum vect_cost_for_stmt type_of_cost,
 579                                     tree vectype,
 580                                     int misalign ATTRIBUTE_UNUSED)
 581 {
 582   unsigned elements;
 583
 584   switch (type_of_cost)
 585     {
 586       case scalar_stmt:
 587       case scalar_load:
 588       case scalar_store:
 589       case vector_stmt:
 590       case vector_load:
 591       case vector_store:
 592       case vec_to_scalar:
 593       case scalar_to_vec:
 594       case cond_branch_not_taken:
 595       case vec_perm:
 596       case vec_promote_demote:
 597         return 1;
 598
 599       case unaligned_load:
 600       case unaligned_store:
 601         return 2;
 602
 603       case cond_branch_taken:
 604         return 3;
 605
 606       case vec_construct:
 607         elements = TYPE_VECTOR_SUBPARTS (vectype);
 608         return elements / 2 + 1;
 609
 610       default:
 611         gcc_unreachable ();
 612     }
 613 }
 614
 615 /* Reciprocal.  */
 616
 617 tree
 618 default_builtin_reciprocal (unsigned int fn ATTRIBUTE_UNUSED,
 619                             bool md_fn ATTRIBUTE_UNUSED,
 620                             bool sqrt ATTRIBUTE_UNUSED)
 621 {
 622   return NULL_TREE;
 623 }
 624
 625 bool
 626 hook_bool_CUMULATIVE_ARGS_mode_tree_bool_false (
 627         cumulative_args_t ca ATTRIBUTE_UNUSED,
 628         machine_mode mode ATTRIBUTE_UNUSED,
 629         const_tree type ATTRIBUTE_UNUSED, bool named ATTRIBUTE_UNUSED)
 630 {
 631   return false;
 632 }
 633
 634 bool
 635 hook_bool_CUMULATIVE_ARGS_mode_tree_bool_true (
 636         cumulative_args_t ca ATTRIBUTE_UNUSED,
 637         machine_mode mode ATTRIBUTE_UNUSED,
 638         const_tree type ATTRIBUTE_UNUSED, bool named ATTRIBUTE_UNUSED)
 639 {
 640   return true;
 641 }
 642
 643 int
 644 hook_int_CUMULATIVE_ARGS_mode_tree_bool_0 (
 645         cumulative_args_t ca ATTRIBUTE_UNUSED,
 646         machine_mode mode ATTRIBUTE_UNUSED,
 647         tree type ATTRIBUTE_UNUSED, bool named ATTRIBUTE_UNUSED)
 648 {
 649   return 0;
 650 }
 651
 652 void
 653 default_function_arg_advance (cumulative_args_t ca ATTRIBUTE_UNUSED,
 654                               machine_mode mode ATTRIBUTE_UNUSED,
 655                               const_tree type ATTRIBUTE_UNUSED,
 656                               bool named ATTRIBUTE_UNUSED)
 657 {
 658   gcc_unreachable ();
 659 }
 660
 661 rtx
 662 default_function_arg (cumulative_args_t ca ATTRIBUTE_UNUSED,
 663                       machine_mode mode ATTRIBUTE_UNUSED,
 664                       const_tree type ATTRIBUTE_UNUSED,
 665                       bool named ATTRIBUTE_UNUSED)
 666 {
 667   gcc_unreachable ();
 668 }
 669
 670 rtx
 671 default_function_incoming_arg (cumulative_args_t ca ATTRIBUTE_UNUSED,
 672                                machine_mode mode ATTRIBUTE_UNUSED,
 673                                const_tree type ATTRIBUTE_UNUSED,
 674                                bool named ATTRIBUTE_UNUSED)
 675 {
 676   gcc_unreachable ();
 677 }
 678
 679 unsigned int
 680 default_function_arg_boundary (machine_mode mode ATTRIBUTE_UNUSED,
 681                                const_tree type ATTRIBUTE_UNUSED)
 682 {
 683   return PARM_BOUNDARY;
 684 }
 685
 686 unsigned int
 687 default_function_arg_round_boundary (machine_mode mode ATTRIBUTE_UNUSED,
 688                                      const_tree type ATTRIBUTE_UNUSED)
 689 {
 690   return PARM_BOUNDARY;
 691 }
 692
 693 void
 694 hook_void_bitmap (bitmap regs ATTRIBUTE_UNUSED)
 695 {
 696 }
 697
 698 const char *
 699 hook_invalid_arg_for_unprototyped_fn (
 700         const_tree typelist ATTRIBUTE_UNUSED,
 701         const_tree funcdecl ATTRIBUTE_UNUSED,
 702         const_tree val ATTRIBUTE_UNUSED)
 703 {
 704   return NULL;
 705 }
 706
 707 /* Initialize the stack protection decls.  */
 708
 709 /* Stack protection related decls living in libgcc.  */
 710 static GTY(()) tree stack_chk_guard_decl;
 711
 712 tree
 713 default_stack_protect_guard (void)
 714 {
 715   tree t = stack_chk_guard_decl;
 716
 717   if (t == NULL)
 718     {
 719       rtx x;
 720
 721       t = build_decl (UNKNOWN_LOCATION,
 722                       VAR_DECL, get_identifier ("__stack_chk_guard"),
 723                       ptr_type_node);
 724       TREE_STATIC (t) = 1;
 725       TREE_PUBLIC (t) = 1;
 726       DECL_EXTERNAL (t) = 1;
 727       TREE_USED (t) = 1;
 728       TREE_THIS_VOLATILE (t) = 1;
 729       DECL_ARTIFICIAL (t) = 1;
 730       DECL_IGNORED_P (t) = 1;
 731
 732       /* Do not share RTL as the declaration is visible outside of
 733          current function.  */
 734       x = DECL_RTL (t);
 735       RTX_FLAG (x, used) = 1;
 736
 737       stack_chk_guard_decl = t;
 738     }
 739
 740   return t;
 741 }
 742
 743 static GTY(()) tree stack_chk_fail_decl;
 744
 745 tree
 746 default_external_stack_protect_fail (void)
 747 {
 748   tree t = stack_chk_fail_decl;
 749
 750   if (t == NULL_TREE)
 751     {
 752       t = build_function_type_list (void_type_node, NULL_TREE);
 753       t = build_decl (UNKNOWN_LOCATION,
 754                       FUNCTION_DECL, get_identifier ("__stack_chk_fail"), t);
 755       TREE_STATIC (t) = 1;
 756       TREE_PUBLIC (t) = 1;
 757       DECL_EXTERNAL (t) = 1;
 758       TREE_USED (t) = 1;
 759       TREE_THIS_VOLATILE (t) = 1;
 760       TREE_NOTHROW (t) = 1;
 761       DECL_ARTIFICIAL (t) = 1;
 762       DECL_IGNORED_P (t) = 1;
 763       DECL_VISIBILITY (t) = VISIBILITY_DEFAULT;
 764       DECL_VISIBILITY_SPECIFIED (t) = 1;
 765
 766       stack_chk_fail_decl = t;
 767     }
 768
 769   return build_call_expr (t, 0);
 770 }
 771
 772 tree
 773 default_hidden_stack_protect_fail (void)
 774 {
 775 #ifndef HAVE_GAS_HIDDEN
 776   return default_external_stack_protect_fail ();
 777 #else
 778   tree t = stack_chk_fail_decl;
 779
 780   if (!flag_pic)
 781     return default_external_stack_protect_fail ();
 782
 783   if (t == NULL_TREE)
 784     {
 785       t = build_function_type_list (void_type_node, NULL_TREE);
 786       t = build_decl (UNKNOWN_LOCATION, FUNCTION_DECL,
 787                       get_identifier ("__stack_chk_fail_local"), t);
 788       TREE_STATIC (t) = 1;
 789       TREE_PUBLIC (t) = 1;
 790       DECL_EXTERNAL (t) = 1;
 791       TREE_USED (t) = 1;
 792       TREE_THIS_VOLATILE (t) = 1;
 793       TREE_NOTHROW (t) = 1;
 794       DECL_ARTIFICIAL (t) = 1;
 795       DECL_IGNORED_P (t) = 1;
 796       DECL_VISIBILITY_SPECIFIED (t) = 1;
 797       DECL_VISIBILITY (t) = VISIBILITY_HIDDEN;
 798
 799       stack_chk_fail_decl = t;
 800     }
 801
 802   return build_call_expr (t, 0);
 803 #endif
 804 }
 805
 806 bool
 807 hook_bool_const_rtx_commutative_p (const_rtx x,
 808                                    int outer_code ATTRIBUTE_UNUSED)
 809 {
 810   return COMMUTATIVE_P (x);
 811 }
 812
 813 rtx
 814 default_function_value (const_tree ret_type ATTRIBUTE_UNUSED,
 815                         const_tree fn_decl_or_type,
 816                         bool outgoing ATTRIBUTE_UNUSED)
 817 {
 818   /* The old interface doesn't handle receiving the function type.  */
 819   if (fn_decl_or_type
 820       && !DECL_P (fn_decl_or_type))
 821     fn_decl_or_type = NULL;
 822
 823 #ifdef FUNCTION_VALUE
 824   return FUNCTION_VALUE (ret_type, fn_decl_or_type);
 825 #else
 826   gcc_unreachable ();
 827 #endif
 828 }
 829
 830 rtx
 831 default_libcall_value (machine_mode mode ATTRIBUTE_UNUSED,
 832                        const_rtx fun ATTRIBUTE_UNUSED)
 833 {
 834 #ifdef LIBCALL_VALUE
 835   return LIBCALL_VALUE (mode);
 836 #else
 837   gcc_unreachable ();
 838 #endif
 839 }
 840
 841 /* The default hook for TARGET_FUNCTION_VALUE_REGNO_P.  */
 842
 843 bool
 844 default_function_value_regno_p (const unsigned int regno ATTRIBUTE_UNUSED)
 845 {
 846 #ifdef FUNCTION_VALUE_REGNO_P
 847   return FUNCTION_VALUE_REGNO_P (regno);
 848 #else
 849   gcc_unreachable ();
 850 #endif
 851 }
 852
 853 rtx
 854 default_internal_arg_pointer (void)
 855 {
 856   /* If the reg that the virtual arg pointer will be translated into is
 857      not a fixed reg or is the stack pointer, make a copy of the virtual
 858      arg pointer, and address parms via the copy.  The frame pointer is
 859      considered fixed even though it is not marked as such.  */
 860   if ((ARG_POINTER_REGNUM == STACK_POINTER_REGNUM
 861        || ! (fixed_regs[ARG_POINTER_REGNUM]
 862              || ARG_POINTER_REGNUM == FRAME_POINTER_REGNUM)))
 863     return copy_to_reg (virtual_incoming_args_rtx);
 864   else
 865     return virtual_incoming_args_rtx;
 866 }
 867
 868 rtx
 869 default_static_chain (const_tree ARG_UNUSED (fndecl_or_type), bool incoming_p)
 870 {
 871   if (incoming_p)
 872     {
 873 #ifdef STATIC_CHAIN_INCOMING_REGNUM
 874       return gen_rtx_REG (Pmode, STATIC_CHAIN_INCOMING_REGNUM);
 875 #endif
 876     }
 877
 878 #ifdef STATIC_CHAIN_REGNUM
 879   return gen_rtx_REG (Pmode, STATIC_CHAIN_REGNUM);
 880 #endif
 881
 882   {
 883     static bool issued_error;
 884     if (!issued_error)
 885       {
 886         issued_error = true;
 887         sorry ("nested functions not supported on this target");
 888       }
 889
 890     /* It really doesn't matter what we return here, so long at it
 891        doesn't cause the rest of the compiler to crash.  */
 892     return gen_rtx_MEM (Pmode, stack_pointer_rtx);
 893   }
 894 }
 895
 896 void
 897 default_trampoline_init (rtx ARG_UNUSED (m_tramp), tree ARG_UNUSED (t_func),
 898                          rtx ARG_UNUSED (r_chain))
 899 {
 900   sorry ("nested function trampolines not supported on this target");
 901 }
 902
 903 int
 904 default_return_pops_args (tree fundecl ATTRIBUTE_UNUSED,
 905                           tree funtype ATTRIBUTE_UNUSED,
 906                           int size ATTRIBUTE_UNUSED)
 907 {
 908   return 0;
 909 }
 910
 911 reg_class_t
 912 default_branch_target_register_class (void)
 913 {
 914   return NO_REGS;
 915 }
 916
 917 reg_class_t
 918 default_ira_change_pseudo_allocno_class (int regno ATTRIBUTE_UNUSED,
 919                                          reg_class_t cl)
 920 {
 921   return cl;
 922 }
 923
 924 extern bool
 925 default_lra_p (void)
 926 {
 927   return false;
 928 }
 929
 930 int
 931 default_register_priority (int hard_regno ATTRIBUTE_UNUSED)
 932 {
 933   return 0;
 934 }
 935
 936 extern bool
 937 default_register_usage_leveling_p (void)
 938 {
 939   return false;
 940 }
 941
 942 extern bool
 943 default_different_addr_displacement_p (void)
 944 {
 945   return false;
 946 }
 947
 948 reg_class_t
 949 default_secondary_reload (bool in_p ATTRIBUTE_UNUSED, rtx x ATTRIBUTE_UNUSED,
 950                           reg_class_t reload_class_i ATTRIBUTE_UNUSED,
 951                           machine_mode reload_mode ATTRIBUTE_UNUSED,
 952                           secondary_reload_info *sri)
 953 {
 954   enum reg_class rclass = NO_REGS;
 955   enum reg_class reload_class = (enum reg_class) reload_class_i;
 956
 957   if (sri->prev_sri && sri->prev_sri->t_icode != CODE_FOR_nothing)
 958     {
 959       sri->icode = sri->prev_sri->t_icode;
 960       return NO_REGS;
 961     }
 962 #ifdef SECONDARY_INPUT_RELOAD_CLASS
 963   if (in_p)
 964     rclass = SECONDARY_INPUT_RELOAD_CLASS (reload_class, reload_mode, x);
 965 #endif
 966 #ifdef SECONDARY_OUTPUT_RELOAD_CLASS
 967   if (! in_p)
 968     rclass = SECONDARY_OUTPUT_RELOAD_CLASS (reload_class, reload_mode, x);
 969 #endif
 970   if (rclass != NO_REGS)
 971     {
 972       enum insn_code icode
 973         = direct_optab_handler (in_p ? reload_in_optab : reload_out_optab,
 974                                 reload_mode);
 975
 976       if (icode != CODE_FOR_nothing
 977           && !insn_operand_matches (icode, in_p, x))
 978         icode = CODE_FOR_nothing;
 979       else if (icode != CODE_FOR_nothing)
 980         {
 981           const char *insn_constraint, *scratch_constraint;
 982           enum reg_class insn_class, scratch_class;
 983
 984           gcc_assert (insn_data[(int) icode].n_operands == 3);
 985           insn_constraint = insn_data[(int) icode].operand[!in_p].constraint;
 986           if (!*insn_constraint)
 987             insn_class = ALL_REGS;
 988           else
 989             {
 990               if (in_p)
 991                 {
 992                   gcc_assert (*insn_constraint == '=');
 993                   insn_constraint++;
 994                 }
 995               insn_class = (reg_class_for_constraint
 996                             (lookup_constraint (insn_constraint)));
 997               gcc_assert (insn_class != NO_REGS);
 998             }
 999
1000           scratch_constraint = insn_data[(int) icode].operand[2].constraint;
1001           /* The scratch register's constraint must start with "=&",
1002              except for an input reload, where only "=" is necessary,
1003              and where it might be beneficial to re-use registers from
1004              the input.  */
1005           gcc_assert (scratch_constraint[0] == '='
1006                       && (in_p || scratch_constraint[1] == '&'));
1007           scratch_constraint++;
1008           if (*scratch_constraint == '&')
1009             scratch_constraint++;
1010           scratch_class = (reg_class_for_constraint
1011                            (lookup_constraint (scratch_constraint)));
1012
1013           if (reg_class_subset_p (reload_class, insn_class))
1014             {
1015               gcc_assert (scratch_class == rclass);
1016               rclass = NO_REGS;
1017             }
1018           else
1019             rclass = insn_class;
1020
1021         }
1022       if (rclass == NO_REGS)
1023         sri->icode = icode;
1024       else
1025         sri->t_icode = icode;
1026     }
1027   return rclass;
1028 }
1029
1030 /* By default, if flag_pic is true, then neither local nor global relocs
1031    should be placed in readonly memory.  */
1032
1033 int
1034 default_reloc_rw_mask (void)
1035 {
1036   return flag_pic ? 3 : 0;
1037 }
1038
1039 /* By default, do no modification. */
1040 tree default_mangle_decl_assembler_name (tree decl ATTRIBUTE_UNUSED,
1041                                          tree id)
1042 {
1043    return id;
1044 }
1045
1046 /* Default to natural alignment for vector types.  */
1047 HOST_WIDE_INT
1048 default_vector_alignment (const_tree type)
1049 {
1050   return tree_to_shwi (TYPE_SIZE (type));
1051 }
1052
1053 bool
1054 default_builtin_vector_alignment_reachable (const_tree type, bool is_packed)
1055 {
1056   if (is_packed)
1057     return false;
1058
1059   /* Assuming that types whose size is > pointer-size are not guaranteed to be
1060      naturally aligned.  */
1061   if (tree_int_cst_compare (TYPE_SIZE (type), bitsize_int (POINTER_SIZE)) > 0)
1062     return false;
1063
1064   /* Assuming that types whose size is <= pointer-size
1065      are naturally aligned.  */
1066   return true;
1067 }
1068
1069 /* By default, assume that a target supports any factor of misalignment
1070    memory access if it supports movmisalign patten.
1071    is_packed is true if the memory access is defined in a packed struct.  */
1072 bool
1073 default_builtin_support_vector_misalignment (machine_mode mode,
1074                                              const_tree type
1075                                              ATTRIBUTE_UNUSED,
1076                                              int misalignment
1077                                              ATTRIBUTE_UNUSED,
1078                                              bool is_packed
1079                                              ATTRIBUTE_UNUSED)
1080 {
1081   if (optab_handler (movmisalign_optab, mode) != CODE_FOR_nothing)
1082     return true;
1083   return false;
1084 }
1085
1086 /* By default, only attempt to parallelize bitwise operations, and
1087    possibly adds/subtracts using bit-twiddling.  */
1088
1089 machine_mode
1090 default_preferred_simd_mode (machine_mode mode ATTRIBUTE_UNUSED)
1091 {
1092   return word_mode;
1093 }
1094
1095 /* By default only the size derived from the preferred vector mode
1096    is tried.  */
1097
1098 unsigned int
1099 default_autovectorize_vector_sizes (void)
1100 {
1101   return 0;
1102 }
1103
1104 /* By default, the cost model accumulates three separate costs (prologue,
1105    loop body, and epilogue) for a vectorized loop or block.  So allocate an
1106    array of three unsigned ints, set it to zero, and return its address.  */
1107
1108 void *
1109 default_init_cost (struct loop *loop_info ATTRIBUTE_UNUSED)
1110 {
1111   unsigned *cost = XNEWVEC (unsigned, 3);
1112   cost[vect_prologue] = cost[vect_body] = cost[vect_epilogue] = 0;
1113   return cost;
1114 }
1115
1116 /* By default, the cost model looks up the cost of the given statement
1117    kind and mode, multiplies it by the occurrence count, accumulates
1118    it into the cost specified by WHERE, and returns the cost added.  */
1119
1120 unsigned
1121 default_add_stmt_cost (void *data, int count, enum vect_cost_for_stmt kind,
1122                        struct _stmt_vec_info *stmt_info, int misalign,
1123                        enum vect_cost_model_location where)
1124 {
1125   unsigned *cost = (unsigned *) data;
1126   unsigned retval = 0;
1127
1128   tree vectype = stmt_info ? stmt_vectype (stmt_info) : NULL_TREE;
1129   int stmt_cost = targetm.vectorize.builtin_vectorization_cost (kind, vectype,
1130                                                                 misalign);
1131    /* Statements in an inner loop relative to the loop being
1132       vectorized are weighted more heavily.  The value here is
1133       arbitrary and could potentially be improved with analysis.  */
1134   if (where == vect_body && stmt_info && stmt_in_inner_loop_p (stmt_info))
1135     count *= 50;  /* FIXME.  */
1136
1137   retval = (unsigned) (count * stmt_cost);
1138   cost[where] += retval;
1139
1140   return retval;
1141 }
1142
1143 /* By default, the cost model just returns the accumulated costs.  */
1144
1145 void
1146 default_finish_cost (void *data, unsigned *prologue_cost,
1147                      unsigned *body_cost, unsigned *epilogue_cost)
1148 {
1149   unsigned *cost = (unsigned *) data;
1150   *prologue_cost = cost[vect_prologue];
1151   *body_cost     = cost[vect_body];
1152   *epilogue_cost = cost[vect_epilogue];
1153 }
1154
1155 /* Free the cost data.  */
1156
1157 void
1158 default_destroy_cost_data (void *data)
1159 {
1160   free (data);
1161 }
1162
1163 /* Determine whether or not a pointer mode is valid. Assume defaults
1164    of ptr_mode or Pmode - can be overridden.  */
1165 bool
1166 default_valid_pointer_mode (machine_mode mode)
1167 {
1168   return (mode == ptr_mode || mode == Pmode);
1169 }
1170
1171 /* Determine whether the memory reference specified by REF may alias
1172    the C libraries errno location.  */
1173 bool
1174 default_ref_may_alias_errno (ao_ref *ref)
1175 {
1176   tree base = ao_ref_base (ref);
1177   /* The default implementation assumes the errno location is
1178      a declaration of type int or is always accessed via a
1179      pointer to int.  We assume that accesses to errno are
1180      not deliberately obfuscated (even in conforming ways).  */
1181   if (TYPE_UNSIGNED (TREE_TYPE (base))
1182       || TYPE_MODE (TREE_TYPE (base)) != TYPE_MODE (integer_type_node))
1183     return false;
1184   /* The default implementation assumes an errno location
1185      declaration is never defined in the current compilation unit.  */
1186   if (DECL_P (base)
1187       && !TREE_STATIC (base))
1188     return true;
1189   else if (TREE_CODE (base) == MEM_REF
1190            && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME)
1191     {
1192       struct ptr_info_def *pi = SSA_NAME_PTR_INFO (TREE_OPERAND (base, 0));
1193       return !pi || pi->pt.anything || pi->pt.nonlocal;
1194     }
1195   return false;
1196 }
1197
1198 /* Return the mode for a pointer to a given ADDRSPACE, defaulting to ptr_mode
1199    for the generic address space only.  */
1200
1201 machine_mode
1202 default_addr_space_pointer_mode (addr_space_t addrspace ATTRIBUTE_UNUSED)
1203 {
1204   gcc_assert (ADDR_SPACE_GENERIC_P (addrspace));
1205   return ptr_mode;
1206 }
1207
1208 /* Return the mode for an address in a given ADDRSPACE, defaulting to Pmode
1209    for the generic address space only.  */
1210
1211 machine_mode
1212 default_addr_space_address_mode (addr_space_t addrspace ATTRIBUTE_UNUSED)
1213 {
1214   gcc_assert (ADDR_SPACE_GENERIC_P (addrspace));
1215   return Pmode;
1216 }
1217
1218 /* Named address space version of valid_pointer_mode.  */
1219
1220 bool
1221 default_addr_space_valid_pointer_mode (machine_mode mode, addr_space_t as)
1222 {
1223   if (!ADDR_SPACE_GENERIC_P (as))
1224     return (mode == targetm.addr_space.pointer_mode (as)
1225             || mode == targetm.addr_space.address_mode (as));
1226
1227   return targetm.valid_pointer_mode (mode);
1228 }
1229
1230 /* Some places still assume that all pointer or address modes are the
1231    standard Pmode and ptr_mode.  These optimizations become invalid if
1232    the target actually supports multiple different modes.  For now,
1233    we disable such optimizations on such targets, using this function.  */
1234
1235 bool
1236 target_default_pointer_address_modes_p (void)
1237 {
1238   if (targetm.addr_space.address_mode != default_addr_space_address_mode)
1239     return false;
1240   if (targetm.addr_space.pointer_mode != default_addr_space_pointer_mode)
1241     return false;
1242
1243   return true;
1244 }
1245
1246 /* Named address space version of legitimate_address_p.  */
1247
1248 bool
1249 default_addr_space_legitimate_address_p (machine_mode mode, rtx mem,
1250                                          bool strict, addr_space_t as)
1251 {
1252   if (!ADDR_SPACE_GENERIC_P (as))
1253     gcc_unreachable ();
1254
1255   return targetm.legitimate_address_p (mode, mem, strict);
1256 }
1257
1258 /* Named address space version of LEGITIMIZE_ADDRESS.  */
1259
1260 rtx
1261 default_addr_space_legitimize_address (rtx x, rtx oldx,
1262                                        machine_mode mode, addr_space_t as)
1263 {
1264   if (!ADDR_SPACE_GENERIC_P (as))
1265     return x;
1266
1267   return targetm.legitimize_address (x, oldx, mode);
1268 }
1269
1270 /* The default hook for determining if one named address space is a subset of
1271    another and to return which address space to use as the common address
1272    space.  */
1273
1274 bool
1275 default_addr_space_subset_p (addr_space_t subset, addr_space_t superset)
1276 {
1277   return (subset == superset);
1278 }
1279
1280 /* The default hook for TARGET_ADDR_SPACE_CONVERT. This hook should never be
1281    called for targets with only a generic address space.  */
1282
1283 rtx
1284 default_addr_space_convert (rtx op ATTRIBUTE_UNUSED,
1285                             tree from_type ATTRIBUTE_UNUSED,
1286                             tree to_type ATTRIBUTE_UNUSED)
1287 {
1288   gcc_unreachable ();
1289 }
1290
1291 bool
1292 default_hard_regno_scratch_ok (unsigned int regno ATTRIBUTE_UNUSED)
1293 {
1294   return true;
1295 }
1296
1297 /* The default implementation of TARGET_MODE_DEPENDENT_ADDRESS_P.  */
1298
1299 bool
1300 default_mode_dependent_address_p (const_rtx addr ATTRIBUTE_UNUSED,
1301                                   addr_space_t addrspace ATTRIBUTE_UNUSED)
1302 {
1303   return false;
1304 }
1305
1306 bool
1307 default_target_option_valid_attribute_p (tree ARG_UNUSED (fndecl),
1308                                          tree ARG_UNUSED (name),
1309                                          tree ARG_UNUSED (args),
1310                                          int ARG_UNUSED (flags))
1311 {
1312   warning (OPT_Wattributes,
1313            "target attribute is not supported on this machine");
1314
1315   return false;
1316 }
1317
1318 bool
1319 default_target_option_pragma_parse (tree ARG_UNUSED (args),
1320                                     tree ARG_UNUSED (pop_target))
1321 {
1322   warning (OPT_Wpragmas,
1323            "#pragma GCC target is not supported for this machine");
1324
1325   return false;
1326 }
1327
1328 bool
1329 default_target_can_inline_p (tree caller, tree callee)
1330 {
1331   bool ret = false;
1332   tree callee_opts = DECL_FUNCTION_SPECIFIC_TARGET (callee);
1333   tree caller_opts = DECL_FUNCTION_SPECIFIC_TARGET (caller);
1334
1335   /* If callee has no option attributes, then it is ok to inline */
1336   if (!callee_opts)
1337     ret = true;
1338
1339   /* If caller has no option attributes, but callee does then it is not ok to
1340      inline */
1341   else if (!caller_opts)
1342     ret = false;
1343
1344   /* If both caller and callee have attributes, assume that if the
1345      pointer is different, the two functions have different target
1346      options since build_target_option_node uses a hash table for the
1347      options.  */
1348   else
1349     ret = (callee_opts == caller_opts);
1350
1351   return ret;
1352 }
1353
1354 #ifndef HAVE_casesi
1355 # define HAVE_casesi 0
1356 #endif
1357
1358 /* If the machine does not have a case insn that compares the bounds,
1359    this means extra overhead for dispatch tables, which raises the
1360    threshold for using them.  */
1361
1362 unsigned int
1363 default_case_values_threshold (void)
1364 {
1365   return (HAVE_casesi ? 4 : 5);
1366 }
1367
1368 bool
1369 default_have_conditional_execution (void)
1370 {
1371 #ifdef HAVE_conditional_execution
1372   return HAVE_conditional_execution;
1373 #else
1374   return false;
1375 #endif
1376 }
1377
1378 /* By default we assume that c99 functions are present at the runtime,
1379    but sincos is not.  */
1380 bool
1381 default_libc_has_function (enum function_class fn_class)
1382 {
1383   if (fn_class == function_c94
1384       || fn_class == function_c99_misc
1385       || fn_class == function_c99_math_complex)
1386     return true;
1387
1388   return false;
1389 }
1390
1391 bool
1392 gnu_libc_has_function (enum function_class fn_class ATTRIBUTE_UNUSED)
1393 {
1394   return true;
1395 }
1396
1397 bool
1398 no_c99_libc_has_function (enum function_class fn_class ATTRIBUTE_UNUSED)
1399 {
1400   return false;
1401 }
1402
1403 tree
1404 default_builtin_tm_load_store (tree ARG_UNUSED (type))
1405 {
1406   return NULL_TREE;
1407 }
1408
1409 /* Compute cost of moving registers to/from memory.  */
1410
1411 int
1412 default_memory_move_cost (machine_mode mode ATTRIBUTE_UNUSED,
1413                           reg_class_t rclass ATTRIBUTE_UNUSED,
1414                           bool in ATTRIBUTE_UNUSED)
1415 {
1416 #ifndef MEMORY_MOVE_COST
1417     return (4 + memory_move_secondary_cost (mode, (enum reg_class) rclass, in));
1418 #else
1419     return MEMORY_MOVE_COST (mode, (enum reg_class) rclass, in);
1420 #endif
1421 }
1422
1423 /* Compute cost of moving data from a register of class FROM to one of
1424    TO, using MODE.  */
1425
1426 int
1427 default_register_move_cost (machine_mode mode ATTRIBUTE_UNUSED,
1428                             reg_class_t from ATTRIBUTE_UNUSED,
1429                             reg_class_t to ATTRIBUTE_UNUSED)
1430 {
1431 #ifndef REGISTER_MOVE_COST
1432   return 2;
1433 #else
1434   return REGISTER_MOVE_COST (mode, (enum reg_class) from, (enum reg_class) to);
1435 #endif
1436 }
1437
1438 /* For hooks which use the MOVE_RATIO macro, this gives the legacy default
1439    behaviour.  SPEED_P is true if we are compiling for speed.  */
1440
1441 unsigned int
1442 get_move_ratio (bool speed_p ATTRIBUTE_UNUSED)
1443 {
1444   unsigned int move_ratio;
1445 #ifdef MOVE_RATIO
1446   move_ratio = (unsigned int) MOVE_RATIO (speed_p);
1447 #else
1448 #if defined (HAVE_movmemqi) || defined (HAVE_movmemhi) || defined (HAVE_movmemsi) || defined (HAVE_movmemdi) || defined (HAVE_movmemti)
1449   move_ratio = 2;
1450 #else /* No movmem patterns, pick a default.  */
1451   move_ratio = ((speed_p) ? 15 : 3);
1452 #endif
1453 #endif
1454   return move_ratio;
1455 }
1456
1457 /* Return TRUE if the move_by_pieces/set_by_pieces infrastructure should be
1458    used; return FALSE if the movmem/setmem optab should be expanded, or
1459    a call to memcpy emitted.  */
1460
1461 bool
1462 default_use_by_pieces_infrastructure_p (unsigned HOST_WIDE_INT size,
1463                                         unsigned int alignment,
1464                                         enum by_pieces_operation op,
1465                                         bool speed_p)
1466 {
1467   unsigned int max_size = 0;
1468   unsigned int ratio = 0;
1469
1470   switch (op)
1471     {
1472       case CLEAR_BY_PIECES:
1473         max_size = STORE_MAX_PIECES;
1474         ratio = CLEAR_RATIO (speed_p);
1475         break;
1476       case MOVE_BY_PIECES:
1477         max_size = MOVE_MAX_PIECES;
1478         ratio = get_move_ratio (speed_p);
1479         break;
1480       case SET_BY_PIECES:
1481         max_size = STORE_MAX_PIECES;
1482         ratio = SET_RATIO (speed_p);
1483         break;
1484       case STORE_BY_PIECES:
1485         max_size = STORE_MAX_PIECES;
1486         ratio = get_move_ratio (speed_p);
1487         break;
1488     }
1489
1490   return move_by_pieces_ninsns (size, alignment, max_size + 1) < ratio;
1491 }
1492
1493 bool
1494 default_profile_before_prologue (void)
1495 {
1496 #ifdef PROFILE_BEFORE_PROLOGUE
1497   return true;
1498 #else
1499   return false;
1500 #endif
1501 }
1502
1503 /* The default implementation of TARGET_PREFERRED_RELOAD_CLASS.  */
1504
1505 reg_class_t
1506 default_preferred_reload_class (rtx x ATTRIBUTE_UNUSED,
1507                                 reg_class_t rclass)
1508 {
1509 #ifdef PREFERRED_RELOAD_CLASS
1510   return (reg_class_t) PREFERRED_RELOAD_CLASS (x, (enum reg_class) rclass);
1511 #else
1512   return rclass;
1513 #endif
1514 }
1515
1516 /* The default implementation of TARGET_OUTPUT_PREFERRED_RELOAD_CLASS.  */
1517
1518 reg_class_t
1519 default_preferred_output_reload_class (rtx x ATTRIBUTE_UNUSED,
1520                                        reg_class_t rclass)
1521 {
1522   return rclass;
1523 }
1524
1525 /* The default implementation of TARGET_PREFERRED_RENAME_CLASS.  */
1526 reg_class_t
1527 default_preferred_rename_class (reg_class_t rclass ATTRIBUTE_UNUSED)
1528 {
1529   return NO_REGS;
1530 }
1531
1532 /* The default implementation of TARGET_CLASS_LIKELY_SPILLED_P.  */
1533
1534 bool
1535 default_class_likely_spilled_p (reg_class_t rclass)
1536 {
1537   return (reg_class_size[(int) rclass] == 1);
1538 }
1539
1540 /* The default implementation of TARGET_CLASS_MAX_NREGS.  */
1541
1542 unsigned char
1543 default_class_max_nregs (reg_class_t rclass ATTRIBUTE_UNUSED,
1544                          machine_mode mode ATTRIBUTE_UNUSED)
1545 {
1546 #ifdef CLASS_MAX_NREGS
1547   return (unsigned char) CLASS_MAX_NREGS ((enum reg_class) rclass, mode);
1548 #else
1549   return ((GET_MODE_SIZE (mode) + UNITS_PER_WORD - 1) / UNITS_PER_WORD);
1550 #endif
1551 }
1552
1553 /* Determine the debugging unwind mechanism for the target.  */
1554
1555 enum unwind_info_type
1556 default_debug_unwind_info (void)
1557 {
1558   /* If the target wants to force the use of dwarf2 unwind info, let it.  */
1559   /* ??? Change all users to the hook, then poison this.  */
1560 #ifdef DWARF2_FRAME_INFO
1561   if (DWARF2_FRAME_INFO)
1562     return UI_DWARF2;
1563 #endif
1564
1565   /* Otherwise, only turn it on if dwarf2 debugging is enabled.  */
1566 #ifdef DWARF2_DEBUGGING_INFO
1567   if (write_symbols == DWARF2_DEBUG || write_symbols == VMS_AND_DWARF2_DEBUG)
1568     return UI_DWARF2;
1569 #endif
1570
1571   return UI_NONE;
1572 }
1573
1574 /* Determine the correct mode for a Dwarf frame register that represents
1575    register REGNO.  */
1576
1577 machine_mode
1578 default_dwarf_frame_reg_mode (int regno)
1579 {
1580   machine_mode save_mode = reg_raw_mode[regno];
1581
1582   if (HARD_REGNO_CALL_PART_CLOBBERED (regno, save_mode))
1583     save_mode = choose_hard_reg_mode (regno, 1, true);
1584   return save_mode;
1585 }
1586
1587 /* To be used by targets where reg_raw_mode doesn't return the right
1588    mode for registers used in apply_builtin_return and apply_builtin_arg.  */
1589
1590 machine_mode
1591 default_get_reg_raw_mode (int regno)
1592 {
1593   return reg_raw_mode[regno];
1594 }
1595
1596 /* Return true if a leaf function should stay leaf even with profiling
1597    enabled.  */
1598
1599 bool
1600 default_keep_leaf_when_profiled ()
1601 {
1602   return false;
1603 }
1604
1605 /* Return true if the state of option OPTION should be stored in PCH files
1606    and checked by default_pch_valid_p.  Store the option's current state
1607    in STATE if so.  */
1608
1609 static inline bool
1610 option_affects_pch_p (int option, struct cl_option_state *state)
1611 {
1612   if ((cl_options[option].flags & CL_TARGET) == 0)
1613     return false;
1614   if ((cl_options[option].flags & CL_PCH_IGNORE) != 0)
1615     return false;
1616   if (option_flag_var (option, &global_options) == &target_flags)
1617     if (targetm.check_pch_target_flags)
1618       return false;
1619   return get_option_state (&global_options, option, state);
1620 }
1621
1622 /* Default version of get_pch_validity.
1623    By default, every flag difference is fatal; that will be mostly right for
1624    most targets, but completely right for very few.  */
1625
1626 void *
1627 default_get_pch_validity (size_t *sz)
1628 {
1629   struct cl_option_state state;
1630   size_t i;
1631   char *result, *r;
1632
1633   *sz = 2;
1634   if (targetm.check_pch_target_flags)
1635     *sz += sizeof (target_flags);
1636   for (i = 0; i < cl_options_count; i++)
1637     if (option_affects_pch_p (i, &state))
1638       *sz += state.size;
1639
1640   result = r = XNEWVEC (char, *sz);
1641   r[0] = flag_pic;
1642   r[1] = flag_pie;
1643   r += 2;
1644   if (targetm.check_pch_target_flags)
1645     {
1646       memcpy (r, &target_flags, sizeof (target_flags));
1647       r += sizeof (target_flags);
1648     }
1649
1650   for (i = 0; i < cl_options_count; i++)
1651     if (option_affects_pch_p (i, &state))
1652       {
1653         memcpy (r, state.data, state.size);
1654         r += state.size;
1655       }
1656
1657   return result;
1658 }
1659
1660 /* Return a message which says that a PCH file was created with a different
1661    setting of OPTION.  */
1662
1663 static const char *
1664 pch_option_mismatch (const char *option)
1665 {
1666   return xasprintf (_("created and used with differing settings of '%s'"),
1667                     option);
1668 }
1669
1670 /* Default version of pch_valid_p.  */
1671
1672 const char *
1673 default_pch_valid_p (const void *data_p, size_t len)
1674 {
1675   struct cl_option_state state;
1676   const char *data = (const char *)data_p;
1677   size_t i;
1678
1679   /* -fpic and -fpie also usually make a PCH invalid.  */
1680   if (data[0] != flag_pic)
1681     return _("created and used with different settings of -fpic");
1682   if (data[1] != flag_pie)
1683     return _("created and used with different settings of -fpie");
1684   data += 2;
1685
1686   /* Check target_flags.  */
1687   if (targetm.check_pch_target_flags)
1688     {
1689       int tf;
1690       const char *r;
1691
1692       memcpy (&tf, data, sizeof (target_flags));
1693       data += sizeof (target_flags);
1694       len -= sizeof (target_flags);
1695       r = targetm.check_pch_target_flags (tf);
1696       if (r != NULL)
1697         return r;
1698     }
1699
1700   for (i = 0; i < cl_options_count; i++)
1701     if (option_affects_pch_p (i, &state))
1702       {
1703         if (memcmp (data, state.data, state.size) != 0)
1704           return pch_option_mismatch (cl_options[i].opt_text);
1705         data += state.size;
1706         len -= state.size;
1707       }
1708
1709   return NULL;
1710 }
1711
1712 /* Default version of cstore_mode.  */
1713
1714 machine_mode
1715 default_cstore_mode (enum insn_code icode)
1716 {
1717   return insn_data[(int) icode].operand[0].mode;
1718 }
1719
1720 /* Default version of member_type_forces_blk.  */
1721
1722 bool
1723 default_member_type_forces_blk (const_tree, machine_mode)
1724 {
1725   return false;
1726 }
1727
1728 rtx
1729 default_load_bounds_for_arg (rtx addr ATTRIBUTE_UNUSED,
1730                              rtx ptr ATTRIBUTE_UNUSED,
1731                              rtx bnd ATTRIBUTE_UNUSED)
1732 {
1733   gcc_unreachable ();
1734 }
1735
1736 void
1737 default_store_bounds_for_arg (rtx val ATTRIBUTE_UNUSED,
1738                               rtx addr ATTRIBUTE_UNUSED,
1739                               rtx bounds ATTRIBUTE_UNUSED,
1740                               rtx to ATTRIBUTE_UNUSED)
1741 {
1742   gcc_unreachable ();
1743 }
1744
1745 rtx
1746 default_load_returned_bounds (rtx slot ATTRIBUTE_UNUSED)
1747 {
1748   gcc_unreachable ();
1749 }
1750
1751 void
1752 default_store_returned_bounds (rtx slot ATTRIBUTE_UNUSED,
1753                                rtx bounds ATTRIBUTE_UNUSED)
1754 {
1755   gcc_unreachable ();
1756 }
1757
1758 /* Default version of canonicalize_comparison.  */
1759
1760 void
1761 default_canonicalize_comparison (int *, rtx *, rtx *, bool)
1762 {
1763 }
1764
1765 /* Default implementation of TARGET_ATOMIC_ASSIGN_EXPAND_FENV.  */
1766
1767 void
1768 default_atomic_assign_expand_fenv (tree *, tree *, tree *)
1769 {
1770 }
1771
1772 #ifndef PAD_VARARGS_DOWN
1773 #define PAD_VARARGS_DOWN BYTES_BIG_ENDIAN
1774 #endif
1775
1776 /* Build an indirect-ref expression over the given TREE, which represents a
1777    piece of a va_arg() expansion.  */
1778 tree
1779 build_va_arg_indirect_ref (tree addr)
1780 {
1781   addr = build_simple_mem_ref_loc (EXPR_LOCATION (addr), addr);
1782   return addr;
1783 }
1784
1785 /* The "standard" implementation of va_arg: read the value from the
1786    current (padded) address and increment by the (padded) size.  */
1787
1788 tree
1789 std_gimplify_va_arg_expr (tree valist, tree type, gimple_seq *pre_p,
1790                           gimple_seq *post_p)
1791 {
1792   tree addr, t, type_size, rounded_size, valist_tmp;
1793   unsigned HOST_WIDE_INT align, boundary;
1794   bool indirect;
1795
1796   /* All of the alignment and movement below is for args-grow-up machines.
1797      As of 2004, there are only 3 ARGS_GROW_DOWNWARD targets, and they all
1798      implement their own specialized gimplify_va_arg_expr routines.  */
1799   if (ARGS_GROW_DOWNWARD)
1800     gcc_unreachable ();
1801
1802   indirect = pass_by_reference (NULL, TYPE_MODE (type), type, false);
1803   if (indirect)
1804     type = build_pointer_type (type);
1805
1806   align = PARM_BOUNDARY / BITS_PER_UNIT;
1807   boundary = targetm.calls.function_arg_boundary (TYPE_MODE (type), type);
1808
1809   /* When we align parameter on stack for caller, if the parameter
1810      alignment is beyond MAX_SUPPORTED_STACK_ALIGNMENT, it will be
1811      aligned at MAX_SUPPORTED_STACK_ALIGNMENT.  We will match callee
1812      here with caller.  */
1813   if (boundary > MAX_SUPPORTED_STACK_ALIGNMENT)
1814     boundary = MAX_SUPPORTED_STACK_ALIGNMENT;
1815
1816   boundary /= BITS_PER_UNIT;
1817
1818   /* Hoist the valist value into a temporary for the moment.  */
1819   valist_tmp = get_initialized_tmp_var (valist, pre_p, NULL);
1820
1821   /* va_list pointer is aligned to PARM_BOUNDARY.  If argument actually
1822      requires greater alignment, we must perform dynamic alignment.  */
1823   if (boundary > align
1824       && !integer_zerop (TYPE_SIZE (type)))
1825     {
1826       t = build2 (MODIFY_EXPR, TREE_TYPE (valist), valist_tmp,
1827                   fold_build_pointer_plus_hwi (valist_tmp, boundary - 1));
1828       gimplify_and_add (t, pre_p);
1829
1830       t = build2 (MODIFY_EXPR, TREE_TYPE (valist), valist_tmp,
1831                   fold_build2 (BIT_AND_EXPR, TREE_TYPE (valist),
1832                                valist_tmp,
1833                                build_int_cst (TREE_TYPE (valist), -boundary)));
1834       gimplify_and_add (t, pre_p);
1835     }
1836   else
1837     boundary = align;
1838
1839   /* If the actual alignment is less than the alignment of the type,
1840      adjust the type accordingly so that we don't assume strict alignment
1841      when dereferencing the pointer.  */
1842   boundary *= BITS_PER_UNIT;
1843   if (boundary < TYPE_ALIGN (type))
1844     {
1845       type = build_variant_type_copy (type);
1846       TYPE_ALIGN (type) = boundary;
1847     }
1848
1849   /* Compute the rounded size of the type.  */
1850   type_size = size_in_bytes (type);
1851   rounded_size = round_up (type_size, align);
1852
1853   /* Reduce rounded_size so it's sharable with the postqueue.  */
1854   gimplify_expr (&rounded_size, pre_p, post_p, is_gimple_val, fb_rvalue);
1855
1856   /* Get AP.  */
1857   addr = valist_tmp;
1858   if (PAD_VARARGS_DOWN && !integer_zerop (rounded_size))
1859     {
1860       /* Small args are padded downward.  */
1861       t = fold_build2_loc (input_location, GT_EXPR, sizetype,
1862                        rounded_size, size_int (align));
1863       t = fold_build3 (COND_EXPR, sizetype, t, size_zero_node,
1864                        size_binop (MINUS_EXPR, rounded_size, type_size));
1865       addr = fold_build_pointer_plus (addr, t);
1866     }
1867
1868   /* Compute new value for AP.  */
1869   t = fold_build_pointer_plus (valist_tmp, rounded_size);
1870   t = build2 (MODIFY_EXPR, TREE_TYPE (valist), valist, t);
1871   gimplify_and_add (t, pre_p);
1872
1873   addr = fold_convert (build_pointer_type (type), addr);
1874
1875   if (indirect)
1876     addr = build_va_arg_indirect_ref (addr);
1877
1878   return build_va_arg_indirect_ref (addr);
1879 }
1880
1881 tree
1882 default_chkp_bound_type (void)
1883 {
1884   tree res = make_node (POINTER_BOUNDS_TYPE);
1885   TYPE_PRECISION (res) = TYPE_PRECISION (size_type_node) * 2;
1886   TYPE_NAME (res) = get_identifier ("__bounds_type");
1887   SET_TYPE_MODE (res, targetm.chkp_bound_mode ());
1888   layout_type (res);
1889   return res;
1890 }
1891
1892 enum machine_mode
1893 default_chkp_bound_mode (void)
1894 {
1895   return VOIDmode;
1896 }
1897
1898 tree
1899 default_builtin_chkp_function (unsigned int fcode ATTRIBUTE_UNUSED)
1900 {
1901   return NULL_TREE;
1902 }
1903
1904 rtx
1905 default_chkp_function_value_bounds (const_tree ret_type ATTRIBUTE_UNUSED,
1906                                     const_tree fn_decl_or_type ATTRIBUTE_UNUSED,
1907                                     bool outgoing ATTRIBUTE_UNUSED)
1908 {
1909   gcc_unreachable ();
1910 }
1911
1912 tree
1913 default_chkp_make_bounds_constant (HOST_WIDE_INT lb ATTRIBUTE_UNUSED,
1914                                    HOST_WIDE_INT ub ATTRIBUTE_UNUSED)
1915 {
1916   return NULL_TREE;
1917 }
1918
1919 int
1920 default_chkp_initialize_bounds (tree var ATTRIBUTE_UNUSED,
1921                                 tree lb ATTRIBUTE_UNUSED,
1922                                 tree ub ATTRIBUTE_UNUSED,
1923                                 tree *stmts ATTRIBUTE_UNUSED)
1924 {
1925   return 0;
1926 }
1927
1928 void
1929 default_setup_incoming_vararg_bounds (cumulative_args_t ca ATTRIBUTE_UNUSED,
1930                                       enum machine_mode mode ATTRIBUTE_UNUSED,
1931                                       tree type ATTRIBUTE_UNUSED,
1932                                       int *pretend_arg_size ATTRIBUTE_UNUSED,
1933                                       int second_time ATTRIBUTE_UNUSED)
1934 {
1935 }
1936
1937 /* An implementation of TARGET_CAN_USE_DOLOOP_P for targets that do
1938    not support nested low-overhead loops.  */
1939
1940 bool
1941 can_use_doloop_if_innermost (const widest_int &, const widest_int &,
1942                              unsigned int loop_depth, bool)
1943 {
1944   return loop_depth == 1;
1945 }
1946
1947 #include "gt-targhooks.h"