gcc/targhooks.c

   1 /* Default target hook functions.
   2    Copyright (C) 2003, 2004, 2005, 2007, 2008, 2009, 2010
   3    Free Software Foundation, Inc.
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify it under
   8 the terms of the GNU General Public License as published by the Free
   9 Software Foundation; either version 3, or (at your option) any later
  10 version.
  11
  12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15 for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GCC; see the file COPYING3.  If not see
  19 <http://www.gnu.org/licenses/>.  */
  20
  21 /* The migration of target macros to target hooks works as follows:
  22
  23    1. Create a target hook that uses the existing target macros to
  24       implement the same functionality.
  25
  26    2. Convert all the MI files to use the hook instead of the macro.
  27
  28    3. Repeat for a majority of the remaining target macros.  This will
  29       take some time.
  30
  31    4. Tell target maintainers to start migrating.
  32
  33    5. Eventually convert the backends to override the hook instead of
  34       defining the macros.  This will take some time too.
  35
  36    6. TBD when, poison the macros.  Unmigrated targets will break at
  37       this point.
  38
  39    Note that we expect steps 1-3 to be done by the people that
  40    understand what the MI does with each macro, and step 5 to be done
  41    by the target maintainers for their respective targets.
  42
  43    Note that steps 1 and 2 don't have to be done together, but no
  44    target can override the new hook until step 2 is complete for it.
  45
  46    Once the macros are poisoned, we will revert to the old migration
  47    rules - migrate the macro, callers, and targets all at once.  This
  48    comment can thus be removed at that point.  */
  49
  50 #include "config.h"
  51 #include "system.h"
  52 #include "coretypes.h"
  53 #include "tm.h"
  54 #include "machmode.h"
  55 #include "rtl.h"
  56 #include "tree.h"
  57 #include "expr.h"
  58 #include "output.h"
  59 #include "diagnostic-core.h"
  60 #include "toplev.h"
  61 #include "function.h"
  62 #include "target.h"
  63 #include "tm_p.h"
  64 #include "target-def.h"
  65 #include "ggc.h"
  66 #include "hard-reg-set.h"
  67 #include "regs.h"
  68 #include "reload.h"
  69 #include "optabs.h"
  70 #include "recog.h"
  71
  72
  73 bool
  74 default_legitimate_address_p (enum machine_mode mode ATTRIBUTE_UNUSED,
  75                               rtx addr ATTRIBUTE_UNUSED,
  76                               bool strict ATTRIBUTE_UNUSED)
  77 {
  78 #ifdef GO_IF_LEGITIMATE_ADDRESS
  79   /* Defer to the old implementation using a goto.  */
  80   if (strict)
  81     return strict_memory_address_p (mode, addr);
  82   else
  83     return memory_address_p (mode, addr);
  84 #else
  85   gcc_unreachable ();
  86 #endif
  87 }
  88
  89 void
  90 default_external_libcall (rtx fun ATTRIBUTE_UNUSED)
  91 {
  92 #ifdef ASM_OUTPUT_EXTERNAL_LIBCALL
  93   ASM_OUTPUT_EXTERNAL_LIBCALL(asm_out_file, fun);
  94 #endif
  95 }
  96
  97 int
  98 default_unspec_may_trap_p (const_rtx x, unsigned flags)
  99 {
 100   int i;
 101
 102   if (GET_CODE (x) == UNSPEC_VOLATILE
 103       /* Any floating arithmetic may trap.  */
 104       || (SCALAR_FLOAT_MODE_P (GET_MODE (x))
 105           && flag_trapping_math))
 106     return 1;
 107
 108   for (i = 0; i < XVECLEN (x, 0); ++i)
 109     {
 110       if (may_trap_p_1 (XVECEXP (x, 0, i), flags))
 111         return 1;
 112     }
 113
 114   return 0;
 115 }
 116
 117 enum machine_mode
 118 default_promote_function_mode (const_tree type ATTRIBUTE_UNUSED,
 119                                enum machine_mode mode,
 120                                int *punsignedp ATTRIBUTE_UNUSED,
 121                                const_tree funtype ATTRIBUTE_UNUSED,
 122                                int for_return ATTRIBUTE_UNUSED)
 123 {
 124   if (for_return == 2)
 125     return promote_mode (type, mode, punsignedp);
 126   return mode;
 127 }
 128
 129 enum machine_mode
 130 default_promote_function_mode_always_promote (const_tree type,
 131                                               enum machine_mode mode,
 132                                               int *punsignedp,
 133                                               const_tree funtype ATTRIBUTE_UNUSED,
 134                                               int for_return ATTRIBUTE_UNUSED)
 135 {
 136   return promote_mode (type, mode, punsignedp);
 137 }
 138
 139
 140 enum machine_mode
 141 default_cc_modes_compatible (enum machine_mode m1, enum machine_mode m2)
 142 {
 143   if (m1 == m2)
 144     return m1;
 145   return VOIDmode;
 146 }
 147
 148 bool
 149 default_return_in_memory (const_tree type,
 150                           const_tree fntype ATTRIBUTE_UNUSED)
 151 {
 152   return (TYPE_MODE (type) == BLKmode);
 153 }
 154
 155 rtx
 156 default_legitimize_address (rtx x, rtx orig_x ATTRIBUTE_UNUSED,
 157                             enum machine_mode mode ATTRIBUTE_UNUSED)
 158 {
 159   return x;
 160 }
 161
 162 rtx
 163 default_expand_builtin_saveregs (void)
 164 {
 165   error ("__builtin_saveregs not supported by this target");
 166   return const0_rtx;
 167 }
 168
 169 void
 170 default_setup_incoming_varargs (CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
 171                                 enum machine_mode mode ATTRIBUTE_UNUSED,
 172                                 tree type ATTRIBUTE_UNUSED,
 173                                 int *pretend_arg_size ATTRIBUTE_UNUSED,
 174                                 int second_time ATTRIBUTE_UNUSED)
 175 {
 176 }
 177
 178 /* The default implementation of TARGET_BUILTIN_SETJMP_FRAME_VALUE.  */
 179
 180 rtx
 181 default_builtin_setjmp_frame_value (void)
 182 {
 183   return virtual_stack_vars_rtx;
 184 }
 185
 186 /* Generic hook that takes a CUMULATIVE_ARGS pointer and returns false.  */
 187
 188 bool
 189 hook_bool_CUMULATIVE_ARGS_false (CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED)
 190 {
 191   return false;
 192 }
 193
 194 bool
 195 default_pretend_outgoing_varargs_named (CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED)
 196 {
 197   return (targetm.calls.setup_incoming_varargs
 198           != default_setup_incoming_varargs);
 199 }
 200
 201 enum machine_mode
 202 default_eh_return_filter_mode (void)
 203 {
 204   return targetm.unwind_word_mode ();
 205 }
 206
 207 enum machine_mode
 208 default_libgcc_cmp_return_mode (void)
 209 {
 210   return word_mode;
 211 }
 212
 213 enum machine_mode
 214 default_libgcc_shift_count_mode (void)
 215 {
 216   return word_mode;
 217 }
 218
 219 enum machine_mode
 220 default_unwind_word_mode (void)
 221 {
 222   return word_mode;
 223 }
 224
 225 /* The default implementation of TARGET_SHIFT_TRUNCATION_MASK.  */
 226
 227 unsigned HOST_WIDE_INT
 228 default_shift_truncation_mask (enum machine_mode mode)
 229 {
 230   return SHIFT_COUNT_TRUNCATED ? GET_MODE_BITSIZE (mode) - 1 : 0;
 231 }
 232
 233 /* The default implementation of TARGET_MIN_DIVISIONS_FOR_RECIP_MUL.  */
 234
 235 unsigned int
 236 default_min_divisions_for_recip_mul (enum machine_mode mode ATTRIBUTE_UNUSED)
 237 {
 238   return have_insn_for (DIV, mode) ? 3 : 2;
 239 }
 240
 241 /* The default implementation of TARGET_MODE_REP_EXTENDED.  */
 242
 243 int
 244 default_mode_rep_extended (enum machine_mode mode ATTRIBUTE_UNUSED,
 245                            enum machine_mode mode_rep ATTRIBUTE_UNUSED)
 246 {
 247   return UNKNOWN;
 248 }
 249
 250 /* Generic hook that takes a CUMULATIVE_ARGS pointer and returns true.  */
 251
 252 bool
 253 hook_bool_CUMULATIVE_ARGS_true (CUMULATIVE_ARGS * a ATTRIBUTE_UNUSED)
 254 {
 255   return true;
 256 }
 257
 258 /* Return machine mode for non-standard suffix
 259    or VOIDmode if non-standard suffixes are unsupported.  */
 260 enum machine_mode
 261 default_mode_for_suffix (char suffix ATTRIBUTE_UNUSED)
 262 {
 263   return VOIDmode;
 264 }
 265
 266 /* The generic C++ ABI specifies this is a 64-bit value.  */
 267 tree
 268 default_cxx_guard_type (void)
 269 {
 270   return long_long_integer_type_node;
 271 }
 272
 273
 274 /* Returns the size of the cookie to use when allocating an array
 275    whose elements have the indicated TYPE.  Assumes that it is already
 276    known that a cookie is needed.  */
 277
 278 tree
 279 default_cxx_get_cookie_size (tree type)
 280 {
 281   tree cookie_size;
 282
 283   /* We need to allocate an additional max (sizeof (size_t), alignof
 284      (true_type)) bytes.  */
 285   tree sizetype_size;
 286   tree type_align;
 287
 288   sizetype_size = size_in_bytes (sizetype);
 289   type_align = size_int (TYPE_ALIGN_UNIT (type));
 290   if (INT_CST_LT_UNSIGNED (type_align, sizetype_size))
 291     cookie_size = sizetype_size;
 292   else
 293     cookie_size = type_align;
 294
 295   return cookie_size;
 296 }
 297
 298 /* Return true if a parameter must be passed by reference.  This version
 299    of the TARGET_PASS_BY_REFERENCE hook uses just MUST_PASS_IN_STACK.  */
 300
 301 bool
 302 hook_pass_by_reference_must_pass_in_stack (CUMULATIVE_ARGS *c ATTRIBUTE_UNUSED,
 303         enum machine_mode mode ATTRIBUTE_UNUSED, const_tree type ATTRIBUTE_UNUSED,
 304         bool named_arg ATTRIBUTE_UNUSED)
 305 {
 306   return targetm.calls.must_pass_in_stack (mode, type);
 307 }
 308
 309 /* Return true if a parameter follows callee copies conventions.  This
 310    version of the hook is true for all named arguments.  */
 311
 312 bool
 313 hook_callee_copies_named (CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
 314                           enum machine_mode mode ATTRIBUTE_UNUSED,
 315                           const_tree type ATTRIBUTE_UNUSED, bool named)
 316 {
 317   return named;
 318 }
 319
 320 /* Emit to STREAM the assembler syntax for insn operand X.  */
 321
 322 void
 323 default_print_operand (FILE *stream ATTRIBUTE_UNUSED, rtx x ATTRIBUTE_UNUSED,
 324                        int code ATTRIBUTE_UNUSED)
 325 {
 326 #ifdef PRINT_OPERAND
 327   PRINT_OPERAND (stream, x, code);
 328 #else
 329   gcc_unreachable ();
 330 #endif
 331 }
 332
 333 /* Emit to STREAM the assembler syntax for an insn operand whose memory
 334    address is X.  */
 335
 336 void
 337 default_print_operand_address (FILE *stream ATTRIBUTE_UNUSED,
 338                                rtx x ATTRIBUTE_UNUSED)
 339 {
 340 #ifdef PRINT_OPERAND_ADDRESS
 341   PRINT_OPERAND_ADDRESS (stream, x);
 342 #else
 343   gcc_unreachable ();
 344 #endif
 345 }
 346
 347 /* Return true if CODE is a valid punctuation character for the
 348    `print_operand' hook.  */
 349
 350 bool
 351 default_print_operand_punct_valid_p (unsigned char code ATTRIBUTE_UNUSED)
 352 {
 353 #ifdef PRINT_OPERAND_PUNCT_VALID_P
 354   return PRINT_OPERAND_PUNCT_VALID_P (code);
 355 #else
 356   return false;
 357 #endif
 358 }
 359
 360 /* The default implementation of TARGET_ASM_OUTPUT_ADDR_CONST_EXTRA.  */
 361
 362 bool
 363 default_asm_output_addr_const_extra (FILE *file ATTRIBUTE_UNUSED,
 364                                      rtx x ATTRIBUTE_UNUSED)
 365 {
 366 #ifdef OUTPUT_ADDR_CONST_EXTRA
 367   OUTPUT_ADDR_CONST_EXTRA (file, x, fail);
 368   return true;
 369
 370 fail:
 371 #endif
 372   return false;
 373 }
 374
 375 /* True if MODE is valid for the target.  By "valid", we mean able to
 376    be manipulated in non-trivial ways.  In particular, this means all
 377    the arithmetic is supported.
 378
 379    By default we guess this means that any C type is supported.  If
 380    we can't map the mode back to a type that would be available in C,
 381    then reject it.  Special case, here, is the double-word arithmetic
 382    supported by optabs.c.  */
 383
 384 bool
 385 default_scalar_mode_supported_p (enum machine_mode mode)
 386 {
 387   int precision = GET_MODE_PRECISION (mode);
 388
 389   switch (GET_MODE_CLASS (mode))
 390     {
 391     case MODE_PARTIAL_INT:
 392     case MODE_INT:
 393       if (precision == CHAR_TYPE_SIZE)
 394         return true;
 395       if (precision == SHORT_TYPE_SIZE)
 396         return true;
 397       if (precision == INT_TYPE_SIZE)
 398         return true;
 399       if (precision == LONG_TYPE_SIZE)
 400         return true;
 401       if (precision == LONG_LONG_TYPE_SIZE)
 402         return true;
 403       if (precision == 2 * BITS_PER_WORD)
 404         return true;
 405       return false;
 406
 407     case MODE_FLOAT:
 408       if (precision == FLOAT_TYPE_SIZE)
 409         return true;
 410       if (precision == DOUBLE_TYPE_SIZE)
 411         return true;
 412       if (precision == LONG_DOUBLE_TYPE_SIZE)
 413         return true;
 414       return false;
 415
 416     case MODE_DECIMAL_FLOAT:
 417     case MODE_FRACT:
 418     case MODE_UFRACT:
 419     case MODE_ACCUM:
 420     case MODE_UACCUM:
 421       return false;
 422
 423     default:
 424       gcc_unreachable ();
 425     }
 426 }
 427
 428 /* Make some target macros useable by target-independent code.  */
 429 bool
 430 targhook_words_big_endian (void)
 431 {
 432   return !!WORDS_BIG_ENDIAN;
 433 }
 434
 435 bool
 436 targhook_float_words_big_endian (void)
 437 {
 438   return !!FLOAT_WORDS_BIG_ENDIAN;
 439 }
 440
 441 /* True if the target supports decimal floating point.  */
 442
 443 bool
 444 default_decimal_float_supported_p (void)
 445 {
 446   return ENABLE_DECIMAL_FLOAT;
 447 }
 448
 449 /* True if the target supports fixed-point arithmetic.  */
 450
 451 bool
 452 default_fixed_point_supported_p (void)
 453 {
 454   return ENABLE_FIXED_POINT;
 455 }
 456
 457 /* NULL if INSN insn is valid within a low-overhead loop, otherwise returns
 458    an error message.
 459
 460    This function checks whether a given INSN is valid within a low-overhead
 461    loop.  If INSN is invalid it returns the reason for that, otherwise it
 462    returns NULL. A called function may clobber any special registers required
 463    for low-overhead looping. Additionally, some targets (eg, PPC) use the count
 464    register for branch on table instructions. We reject the doloop pattern in
 465    these cases.  */
 466
 467 const char *
 468 default_invalid_within_doloop (const_rtx insn)
 469 {
 470   if (CALL_P (insn))
 471     return "Function call in loop.";
 472
 473   if (JUMP_TABLE_DATA_P (insn))
 474     return "Computed branch in the loop.";
 475
 476   return NULL;
 477 }
 478
 479 /* Mapping of builtin functions to vectorized variants.  */
 480
 481 tree
 482 default_builtin_vectorized_function (tree fndecl ATTRIBUTE_UNUSED,
 483                                      tree type_out ATTRIBUTE_UNUSED,
 484                                      tree type_in ATTRIBUTE_UNUSED)
 485 {
 486   return NULL_TREE;
 487 }
 488
 489 /* Vectorized conversion.  */
 490
 491 tree
 492 default_builtin_vectorized_conversion (unsigned int code ATTRIBUTE_UNUSED,
 493                                        tree dest_type ATTRIBUTE_UNUSED,
 494                                        tree src_type ATTRIBUTE_UNUSED)
 495 {
 496   return NULL_TREE;
 497 }
 498
 499 /* Default vectorizer cost model values.  */
 500
 501 int
 502 default_builtin_vectorization_cost (enum vect_cost_for_stmt type_of_cost,
 503                                     tree vectype ATTRIBUTE_UNUSED,
 504                                     int misalign ATTRIBUTE_UNUSED)
 505 {
 506   switch (type_of_cost)
 507     {
 508       case scalar_stmt:
 509       case scalar_load:
 510       case scalar_store:
 511       case vector_stmt:
 512       case vector_load:
 513       case vector_store:
 514       case vec_to_scalar:
 515       case scalar_to_vec:
 516       case cond_branch_not_taken:
 517       case vec_perm:
 518         return 1;
 519
 520       case unaligned_load:
 521       case unaligned_store:
 522         return 2;
 523
 524       case cond_branch_taken:
 525         return 3;
 526
 527       default:
 528         gcc_unreachable ();
 529     }
 530 }
 531
 532 /* Reciprocal.  */
 533
 534 tree
 535 default_builtin_reciprocal (unsigned int fn ATTRIBUTE_UNUSED,
 536                             bool md_fn ATTRIBUTE_UNUSED,
 537                             bool sqrt ATTRIBUTE_UNUSED)
 538 {
 539   return NULL_TREE;
 540 }
 541
 542 bool
 543 hook_bool_CUMULATIVE_ARGS_mode_tree_bool_false (
 544         CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
 545         enum machine_mode mode ATTRIBUTE_UNUSED,
 546         const_tree type ATTRIBUTE_UNUSED, bool named ATTRIBUTE_UNUSED)
 547 {
 548   return false;
 549 }
 550
 551 bool
 552 hook_bool_CUMULATIVE_ARGS_mode_tree_bool_true (
 553         CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
 554         enum machine_mode mode ATTRIBUTE_UNUSED,
 555         const_tree type ATTRIBUTE_UNUSED, bool named ATTRIBUTE_UNUSED)
 556 {
 557   return true;
 558 }
 559
 560 int
 561 hook_int_CUMULATIVE_ARGS_mode_tree_bool_0 (
 562         CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
 563         enum machine_mode mode ATTRIBUTE_UNUSED,
 564         tree type ATTRIBUTE_UNUSED, bool named ATTRIBUTE_UNUSED)
 565 {
 566   return 0;
 567 }
 568
 569 void
 570 default_function_arg_advance (CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
 571                               enum machine_mode mode ATTRIBUTE_UNUSED,
 572                               const_tree type ATTRIBUTE_UNUSED,
 573                               bool named ATTRIBUTE_UNUSED)
 574 {
 575 #ifdef FUNCTION_ARG_ADVANCE
 576   CUMULATIVE_ARGS args = *ca;
 577   FUNCTION_ARG_ADVANCE (args, mode, CONST_CAST_TREE (type), named);
 578   *ca = args;
 579 #else
 580   gcc_unreachable ();
 581 #endif
 582 }
 583
 584 rtx
 585 default_function_arg (CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
 586                       enum machine_mode mode ATTRIBUTE_UNUSED,
 587                       const_tree type ATTRIBUTE_UNUSED,
 588                       bool named ATTRIBUTE_UNUSED)
 589 {
 590 #ifdef FUNCTION_ARG
 591   return FUNCTION_ARG (*ca, mode, CONST_CAST_TREE (type), named);
 592 #else
 593   gcc_unreachable ();
 594 #endif
 595 }
 596
 597 rtx
 598 default_function_incoming_arg (CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
 599                                enum machine_mode mode ATTRIBUTE_UNUSED,
 600                                const_tree type ATTRIBUTE_UNUSED,
 601                                bool named ATTRIBUTE_UNUSED)
 602 {
 603 #ifdef FUNCTION_INCOMING_ARG
 604   return FUNCTION_INCOMING_ARG (*ca, mode, CONST_CAST_TREE (type), named);
 605 #else
 606   gcc_unreachable ();
 607 #endif
 608 }
 609
 610 void
 611 hook_void_bitmap (bitmap regs ATTRIBUTE_UNUSED)
 612 {
 613 }
 614
 615 const char *
 616 hook_invalid_arg_for_unprototyped_fn (
 617         const_tree typelist ATTRIBUTE_UNUSED,
 618         const_tree funcdecl ATTRIBUTE_UNUSED,
 619         const_tree val ATTRIBUTE_UNUSED)
 620 {
 621   return NULL;
 622 }
 623
 624 /* Initialize the stack protection decls.  */
 625
 626 /* Stack protection related decls living in libgcc.  */
 627 static GTY(()) tree stack_chk_guard_decl;
 628
 629 tree
 630 default_stack_protect_guard (void)
 631 {
 632   tree t = stack_chk_guard_decl;
 633
 634   if (t == NULL)
 635     {
 636       rtx x;
 637
 638       t = build_decl (UNKNOWN_LOCATION,
 639                       VAR_DECL, get_identifier ("__stack_chk_guard"),
 640                       ptr_type_node);
 641       TREE_STATIC (t) = 1;
 642       TREE_PUBLIC (t) = 1;
 643       DECL_EXTERNAL (t) = 1;
 644       TREE_USED (t) = 1;
 645       TREE_THIS_VOLATILE (t) = 1;
 646       DECL_ARTIFICIAL (t) = 1;
 647       DECL_IGNORED_P (t) = 1;
 648
 649       /* Do not share RTL as the declaration is visible outside of
 650          current function.  */
 651       x = DECL_RTL (t);
 652       RTX_FLAG (x, used) = 1;
 653
 654       stack_chk_guard_decl = t;
 655     }
 656
 657   return t;
 658 }
 659
 660 static GTY(()) tree stack_chk_fail_decl;
 661
 662 tree
 663 default_external_stack_protect_fail (void)
 664 {
 665   tree t = stack_chk_fail_decl;
 666
 667   if (t == NULL_TREE)
 668     {
 669       t = build_function_type_list (void_type_node, NULL_TREE);
 670       t = build_decl (UNKNOWN_LOCATION,
 671                       FUNCTION_DECL, get_identifier ("__stack_chk_fail"), t);
 672       TREE_STATIC (t) = 1;
 673       TREE_PUBLIC (t) = 1;
 674       DECL_EXTERNAL (t) = 1;
 675       TREE_USED (t) = 1;
 676       TREE_THIS_VOLATILE (t) = 1;
 677       TREE_NOTHROW (t) = 1;
 678       DECL_ARTIFICIAL (t) = 1;
 679       DECL_IGNORED_P (t) = 1;
 680       DECL_VISIBILITY (t) = VISIBILITY_DEFAULT;
 681       DECL_VISIBILITY_SPECIFIED (t) = 1;
 682
 683       stack_chk_fail_decl = t;
 684     }
 685
 686   return build_call_expr (t, 0);
 687 }
 688
 689 tree
 690 default_hidden_stack_protect_fail (void)
 691 {
 692 #ifndef HAVE_GAS_HIDDEN
 693   return default_external_stack_protect_fail ();
 694 #else
 695   tree t = stack_chk_fail_decl;
 696
 697   if (!flag_pic)
 698     return default_external_stack_protect_fail ();
 699
 700   if (t == NULL_TREE)
 701     {
 702       t = build_function_type_list (void_type_node, NULL_TREE);
 703       t = build_decl (UNKNOWN_LOCATION, FUNCTION_DECL,
 704                       get_identifier ("__stack_chk_fail_local"), t);
 705       TREE_STATIC (t) = 1;
 706       TREE_PUBLIC (t) = 1;
 707       DECL_EXTERNAL (t) = 1;
 708       TREE_USED (t) = 1;
 709       TREE_THIS_VOLATILE (t) = 1;
 710       TREE_NOTHROW (t) = 1;
 711       DECL_ARTIFICIAL (t) = 1;
 712       DECL_IGNORED_P (t) = 1;
 713       DECL_VISIBILITY_SPECIFIED (t) = 1;
 714       DECL_VISIBILITY (t) = VISIBILITY_HIDDEN;
 715
 716       stack_chk_fail_decl = t;
 717     }
 718
 719   return build_call_expr (t, 0);
 720 #endif
 721 }
 722
 723 bool
 724 hook_bool_const_rtx_commutative_p (const_rtx x,
 725                                    int outer_code ATTRIBUTE_UNUSED)
 726 {
 727   return COMMUTATIVE_P (x);
 728 }
 729
 730 rtx
 731 default_function_value (const_tree ret_type ATTRIBUTE_UNUSED,
 732                         const_tree fn_decl_or_type,
 733                         bool outgoing ATTRIBUTE_UNUSED)
 734 {
 735   /* The old interface doesn't handle receiving the function type.  */
 736   if (fn_decl_or_type
 737       && !DECL_P (fn_decl_or_type))
 738     fn_decl_or_type = NULL;
 739
 740 #ifdef FUNCTION_VALUE
 741   return FUNCTION_VALUE (ret_type, fn_decl_or_type);
 742 #else
 743   gcc_unreachable ();
 744 #endif
 745 }
 746
 747 rtx
 748 default_libcall_value (enum machine_mode mode ATTRIBUTE_UNUSED,
 749                        const_rtx fun ATTRIBUTE_UNUSED)
 750 {
 751 #ifdef LIBCALL_VALUE
 752   return LIBCALL_VALUE (mode);
 753 #else
 754   gcc_unreachable ();
 755 #endif
 756 }
 757
 758 /* The default hook for TARGET_FUNCTION_VALUE_REGNO_P.  */
 759
 760 bool
 761 default_function_value_regno_p (const unsigned int regno ATTRIBUTE_UNUSED)
 762 {
 763 #ifdef FUNCTION_VALUE_REGNO_P
 764   return FUNCTION_VALUE_REGNO_P (regno);
 765 #else
 766   gcc_unreachable ();
 767 #endif
 768 }
 769
 770 rtx
 771 default_internal_arg_pointer (void)
 772 {
 773   /* If the reg that the virtual arg pointer will be translated into is
 774      not a fixed reg or is the stack pointer, make a copy of the virtual
 775      arg pointer, and address parms via the copy.  The frame pointer is
 776      considered fixed even though it is not marked as such.  */
 777   if ((ARG_POINTER_REGNUM == STACK_POINTER_REGNUM
 778        || ! (fixed_regs[ARG_POINTER_REGNUM]
 779              || ARG_POINTER_REGNUM == FRAME_POINTER_REGNUM)))
 780     return copy_to_reg (virtual_incoming_args_rtx);
 781   else
 782     return virtual_incoming_args_rtx;
 783 }
 784
 785 rtx
 786 default_static_chain (const_tree fndecl, bool incoming_p)
 787 {
 788   if (!DECL_STATIC_CHAIN (fndecl))
 789     return NULL;
 790
 791   if (incoming_p)
 792     {
 793 #ifdef STATIC_CHAIN_INCOMING_REGNUM
 794       return gen_rtx_REG (Pmode, STATIC_CHAIN_INCOMING_REGNUM);
 795 #endif
 796     }
 797
 798 #ifdef STATIC_CHAIN_REGNUM
 799   return gen_rtx_REG (Pmode, STATIC_CHAIN_REGNUM);
 800 #endif
 801
 802   {
 803     static bool issued_error;
 804     if (!issued_error)
 805       {
 806         issued_error = true;
 807         sorry ("nested functions not supported on this target");
 808       }
 809
 810     /* It really doesn't matter what we return here, so long at it
 811        doesn't cause the rest of the compiler to crash.  */
 812     return gen_rtx_MEM (Pmode, stack_pointer_rtx);
 813   }
 814 }
 815
 816 void
 817 default_trampoline_init (rtx ARG_UNUSED (m_tramp), tree ARG_UNUSED (t_func),
 818                          rtx ARG_UNUSED (r_chain))
 819 {
 820   sorry ("nested function trampolines not supported on this target");
 821 }
 822
 823 int
 824 default_return_pops_args (tree fundecl ATTRIBUTE_UNUSED,
 825                           tree funtype ATTRIBUTE_UNUSED,
 826                           int size ATTRIBUTE_UNUSED)
 827 {
 828   return 0;
 829 }
 830
 831 reg_class_t
 832 default_branch_target_register_class (void)
 833 {
 834   return NO_REGS;
 835 }
 836
 837 #ifdef IRA_COVER_CLASSES
 838 const reg_class_t *
 839 default_ira_cover_classes (void)
 840 {
 841   static reg_class_t classes[] = IRA_COVER_CLASSES;
 842   return classes;
 843 }
 844 #endif
 845
 846 reg_class_t
 847 default_secondary_reload (bool in_p ATTRIBUTE_UNUSED, rtx x ATTRIBUTE_UNUSED,
 848                           reg_class_t reload_class_i ATTRIBUTE_UNUSED,
 849                           enum machine_mode reload_mode ATTRIBUTE_UNUSED,
 850                           secondary_reload_info *sri)
 851 {
 852   enum reg_class rclass = NO_REGS;
 853   enum reg_class reload_class = (enum reg_class) reload_class_i;
 854
 855   if (sri->prev_sri && sri->prev_sri->t_icode != CODE_FOR_nothing)
 856     {
 857       sri->icode = sri->prev_sri->t_icode;
 858       return NO_REGS;
 859     }
 860 #ifdef SECONDARY_INPUT_RELOAD_CLASS
 861   if (in_p)
 862     rclass = SECONDARY_INPUT_RELOAD_CLASS (reload_class, reload_mode, x);
 863 #endif
 864 #ifdef SECONDARY_OUTPUT_RELOAD_CLASS
 865   if (! in_p)
 866     rclass = SECONDARY_OUTPUT_RELOAD_CLASS (reload_class, reload_mode, x);
 867 #endif
 868   if (rclass != NO_REGS)
 869     {
 870       enum insn_code icode
 871         = direct_optab_handler (in_p ? reload_in_optab : reload_out_optab,
 872                                 reload_mode);
 873
 874       if (icode != CODE_FOR_nothing
 875           && insn_data[(int) icode].operand[in_p].predicate
 876           && ! insn_data[(int) icode].operand[in_p].predicate (x, reload_mode))
 877         icode = CODE_FOR_nothing;
 878       else if (icode != CODE_FOR_nothing)
 879         {
 880           const char *insn_constraint, *scratch_constraint;
 881           char insn_letter, scratch_letter;
 882           enum reg_class insn_class, scratch_class;
 883
 884           gcc_assert (insn_data[(int) icode].n_operands == 3);
 885           insn_constraint = insn_data[(int) icode].operand[!in_p].constraint;
 886           if (!*insn_constraint)
 887             insn_class = ALL_REGS;
 888           else
 889             {
 890               if (in_p)
 891                 {
 892                   gcc_assert (*insn_constraint == '=');
 893                   insn_constraint++;
 894                 }
 895               insn_letter = *insn_constraint;
 896               insn_class
 897                 = (insn_letter == 'r' ? GENERAL_REGS
 898                    : REG_CLASS_FROM_CONSTRAINT ((unsigned char) insn_letter,
 899                                                 insn_constraint));
 900               gcc_assert (insn_class != NO_REGS);
 901             }
 902
 903           scratch_constraint = insn_data[(int) icode].operand[2].constraint;
 904           /* The scratch register's constraint must start with "=&",
 905              except for an input reload, where only "=" is necessary,
 906              and where it might be beneficial to re-use registers from
 907              the input.  */
 908           gcc_assert (scratch_constraint[0] == '='
 909                       && (in_p || scratch_constraint[1] == '&'));
 910           scratch_constraint++;
 911           if (*scratch_constraint == '&')
 912             scratch_constraint++;
 913           scratch_letter = *scratch_constraint;
 914           scratch_class
 915             = (scratch_letter == 'r' ? GENERAL_REGS
 916                : REG_CLASS_FROM_CONSTRAINT ((unsigned char) scratch_letter,
 917                                             scratch_constraint));
 918
 919           if (reg_class_subset_p (reload_class, insn_class))
 920             {
 921               gcc_assert (scratch_class == rclass);
 922               rclass = NO_REGS;
 923             }
 924           else
 925             rclass = insn_class;
 926
 927         }
 928       if (rclass == NO_REGS)
 929         sri->icode = icode;
 930       else
 931         sri->t_icode = icode;
 932     }
 933   return rclass;
 934 }
 935
 936 bool
 937 default_handle_c_option (size_t code ATTRIBUTE_UNUSED,
 938                          const char *arg ATTRIBUTE_UNUSED,
 939                          int value ATTRIBUTE_UNUSED)
 940 {
 941   return false;
 942 }
 943
 944 /* By default, if flag_pic is true, then neither local nor global relocs
 945    should be placed in readonly memory.  */
 946
 947 int
 948 default_reloc_rw_mask (void)
 949 {
 950   return flag_pic ? 3 : 0;
 951 }
 952
 953 /* By default, do no modification. */
 954 tree default_mangle_decl_assembler_name (tree decl ATTRIBUTE_UNUSED,
 955                                          tree id)
 956 {
 957    return id;
 958 }
 959
 960 bool
 961 default_builtin_vector_alignment_reachable (const_tree type, bool is_packed)
 962 {
 963   if (is_packed)
 964     return false;
 965
 966   /* Assuming that types whose size is > pointer-size are not guaranteed to be
 967      naturally aligned.  */
 968   if (tree_int_cst_compare (TYPE_SIZE (type), bitsize_int (POINTER_SIZE)) > 0)
 969     return false;
 970
 971   /* Assuming that types whose size is <= pointer-size
 972      are naturally aligned.  */
 973   return true;
 974 }
 975
 976 /* By default, assume that a target supports any factor of misalignment
 977    memory access if it supports movmisalign patten.
 978    is_packed is true if the memory access is defined in a packed struct.  */
 979 bool
 980 default_builtin_support_vector_misalignment (enum machine_mode mode,
 981                                              const_tree type
 982                                              ATTRIBUTE_UNUSED,
 983                                              int misalignment
 984                                              ATTRIBUTE_UNUSED,
 985                                              bool is_packed
 986                                              ATTRIBUTE_UNUSED)
 987 {
 988   if (optab_handler (movmisalign_optab, mode) != CODE_FOR_nothing)
 989     return true;
 990   return false;
 991 }
 992
 993 /* By default, only attempt to parallelize bitwise operations, and
 994    possibly adds/subtracts using bit-twiddling.  */
 995
 996 enum machine_mode
 997 default_preferred_simd_mode (enum machine_mode mode ATTRIBUTE_UNUSED)
 998 {
 999   return word_mode;
1000 }
1001
1002 /* By default only the size derived from the preferred vector mode
1003    is tried.  */
1004
1005 unsigned int
1006 default_autovectorize_vector_sizes (void)
1007 {
1008   return 0;
1009 }
1010
1011 /* Determine whether or not a pointer mode is valid. Assume defaults
1012    of ptr_mode or Pmode - can be overridden.  */
1013 bool
1014 default_valid_pointer_mode (enum machine_mode mode)
1015 {
1016   return (mode == ptr_mode || mode == Pmode);
1017 }
1018
1019 /* Return the mode for a pointer to a given ADDRSPACE, defaulting to ptr_mode
1020    for the generic address space only.  */
1021
1022 enum machine_mode
1023 default_addr_space_pointer_mode (addr_space_t addrspace ATTRIBUTE_UNUSED)
1024 {
1025   gcc_assert (ADDR_SPACE_GENERIC_P (addrspace));
1026   return ptr_mode;
1027 }
1028
1029 /* Return the mode for an address in a given ADDRSPACE, defaulting to Pmode
1030    for the generic address space only.  */
1031
1032 enum machine_mode
1033 default_addr_space_address_mode (addr_space_t addrspace ATTRIBUTE_UNUSED)
1034 {
1035   gcc_assert (ADDR_SPACE_GENERIC_P (addrspace));
1036   return Pmode;
1037 }
1038
1039 /* Named address space version of valid_pointer_mode.  */
1040
1041 bool
1042 default_addr_space_valid_pointer_mode (enum machine_mode mode, addr_space_t as)
1043 {
1044   if (!ADDR_SPACE_GENERIC_P (as))
1045     return (mode == targetm.addr_space.pointer_mode (as)
1046             || mode == targetm.addr_space.address_mode (as));
1047
1048   return targetm.valid_pointer_mode (mode);
1049 }
1050
1051 /* Some places still assume that all pointer or address modes are the
1052    standard Pmode and ptr_mode.  These optimizations become invalid if
1053    the target actually supports multiple different modes.  For now,
1054    we disable such optimizations on such targets, using this function.  */
1055
1056 bool
1057 target_default_pointer_address_modes_p (void)
1058 {
1059   if (targetm.addr_space.address_mode != default_addr_space_address_mode)
1060     return false;
1061   if (targetm.addr_space.pointer_mode != default_addr_space_pointer_mode)
1062     return false;
1063
1064   return true;
1065 }
1066
1067 /* Named address space version of legitimate_address_p.  */
1068
1069 bool
1070 default_addr_space_legitimate_address_p (enum machine_mode mode, rtx mem,
1071                                          bool strict, addr_space_t as)
1072 {
1073   if (!ADDR_SPACE_GENERIC_P (as))
1074     gcc_unreachable ();
1075
1076   return targetm.legitimate_address_p (mode, mem, strict);
1077 }
1078
1079 /* Named address space version of LEGITIMIZE_ADDRESS.  */
1080
1081 rtx
1082 default_addr_space_legitimize_address (rtx x, rtx oldx,
1083                                        enum machine_mode mode, addr_space_t as)
1084 {
1085   if (!ADDR_SPACE_GENERIC_P (as))
1086     return x;
1087
1088   return targetm.legitimize_address (x, oldx, mode);
1089 }
1090
1091 /* The default hook for determining if one named address space is a subset of
1092    another and to return which address space to use as the common address
1093    space.  */
1094
1095 bool
1096 default_addr_space_subset_p (addr_space_t subset, addr_space_t superset)
1097 {
1098   return (subset == superset);
1099 }
1100
1101 /* The default hook for TARGET_ADDR_SPACE_CONVERT. This hook should never be
1102    called for targets with only a generic address space.  */
1103
1104 rtx
1105 default_addr_space_convert (rtx op ATTRIBUTE_UNUSED,
1106                             tree from_type ATTRIBUTE_UNUSED,
1107                             tree to_type ATTRIBUTE_UNUSED)
1108 {
1109   gcc_unreachable ();
1110 }
1111
1112 bool
1113 default_hard_regno_scratch_ok (unsigned int regno ATTRIBUTE_UNUSED)
1114 {
1115   return true;
1116 }
1117
1118 /* The default implementation of TARGET_MODE_DEPENDENT_ADDRESS_P.  */
1119
1120 bool
1121 default_mode_dependent_address_p (const_rtx addr ATTRIBUTE_UNUSED)
1122 {
1123 #ifdef GO_IF_MODE_DEPENDENT_ADDRESS
1124
1125   GO_IF_MODE_DEPENDENT_ADDRESS (CONST_CAST_RTX (addr), win);
1126   return false;
1127   /* Label `win' might (not) be used via GO_IF_MODE_DEPENDENT_ADDRESS.  */
1128  win: ATTRIBUTE_UNUSED_LABEL
1129   return true;
1130
1131 #else
1132
1133   return false;
1134
1135 #endif
1136 }
1137
1138 bool
1139 default_target_option_valid_attribute_p (tree ARG_UNUSED (fndecl),
1140                                          tree ARG_UNUSED (name),
1141                                          tree ARG_UNUSED (args),
1142                                          int ARG_UNUSED (flags))
1143 {
1144   warning (OPT_Wattributes,
1145            "target attribute is not supported on this machine");
1146
1147   return false;
1148 }
1149
1150 bool
1151 default_target_option_pragma_parse (tree ARG_UNUSED (args),
1152                                     tree ARG_UNUSED (pop_target))
1153 {
1154   warning (OPT_Wpragmas,
1155            "#pragma GCC target is not supported for this machine");
1156
1157   return false;
1158 }
1159
1160 bool
1161 default_target_can_inline_p (tree caller, tree callee)
1162 {
1163   bool ret = false;
1164   tree callee_opts = DECL_FUNCTION_SPECIFIC_TARGET (callee);
1165   tree caller_opts = DECL_FUNCTION_SPECIFIC_TARGET (caller);
1166
1167   /* If callee has no option attributes, then it is ok to inline */
1168   if (!callee_opts)
1169     ret = true;
1170
1171   /* If caller has no option attributes, but callee does then it is not ok to
1172      inline */
1173   else if (!caller_opts)
1174     ret = false;
1175
1176   /* If both caller and callee have attributes, assume that if the pointer is
1177      different, the the two functions have different target options since
1178      build_target_option_node uses a hash table for the options.  */
1179   else
1180     ret = (callee_opts == caller_opts);
1181
1182   return ret;
1183 }
1184
1185 #ifndef HAVE_casesi
1186 # define HAVE_casesi 0
1187 #endif
1188
1189 /* If the machine does not have a case insn that compares the bounds,
1190    this means extra overhead for dispatch tables, which raises the
1191    threshold for using them.  */
1192
1193 unsigned int default_case_values_threshold (void)
1194 {
1195   return (HAVE_casesi ? 4 : 5);
1196 }
1197
1198 bool
1199 default_have_conditional_execution (void)
1200 {
1201 #ifdef HAVE_conditional_execution
1202   return HAVE_conditional_execution;
1203 #else
1204   return false;
1205 #endif
1206 }
1207
1208 /* Compute cost of moving registers to/from memory.  */
1209
1210 int
1211 default_memory_move_cost (enum machine_mode mode ATTRIBUTE_UNUSED,
1212                           reg_class_t rclass ATTRIBUTE_UNUSED,
1213                           bool in ATTRIBUTE_UNUSED)
1214 {
1215 #ifndef MEMORY_MOVE_COST
1216     return (4 + memory_move_secondary_cost (mode, (enum reg_class) rclass, in));
1217 #else
1218     return MEMORY_MOVE_COST (mode, (enum reg_class) rclass, in);
1219 #endif
1220 }
1221
1222 /* Compute cost of moving data from a register of class FROM to one of
1223    TO, using MODE.  */
1224
1225 int
1226 default_register_move_cost (enum machine_mode mode ATTRIBUTE_UNUSED,
1227                             reg_class_t from ATTRIBUTE_UNUSED,
1228                             reg_class_t to ATTRIBUTE_UNUSED)
1229 {
1230 #ifndef REGISTER_MOVE_COST
1231   return 2;
1232 #else
1233   return REGISTER_MOVE_COST (mode, (enum reg_class) from, (enum reg_class) to);
1234 #endif
1235 }
1236
1237 bool
1238 default_profile_before_prologue (void)
1239 {
1240 #ifdef PROFILE_BEFORE_PROLOGUE
1241   return true;
1242 #else
1243   return false;
1244 #endif
1245 }
1246
1247 /* The default implementation of TARGET_PREFERRED_RELOAD_CLASS.  */
1248
1249 reg_class_t
1250 default_preferred_reload_class (rtx x ATTRIBUTE_UNUSED,
1251                                 reg_class_t rclass)
1252 {
1253 #ifdef PREFERRED_RELOAD_CLASS
1254   return (reg_class_t) PREFERRED_RELOAD_CLASS (x, (enum reg_class) rclass);
1255 #else
1256   return rclass;
1257 #endif
1258 }
1259
1260 /* The default implementation of TARGET_OUTPUT_PREFERRED_RELOAD_CLASS.  */
1261
1262 reg_class_t
1263 default_preferred_output_reload_class (rtx x ATTRIBUTE_UNUSED,
1264                                        reg_class_t rclass)
1265 {
1266 #ifdef PREFERRED_OUTPUT_RELOAD_CLASS
1267   return PREFERRED_OUTPUT_RELOAD_CLASS (x, (enum reg_class) rclass);
1268 #else
1269   return rclass;
1270 #endif
1271 }
1272
1273 /* The default implementation of TARGET_CLASS_LIKELY_SPILLED_P.  */
1274
1275 bool
1276 default_class_likely_spilled_p (reg_class_t rclass)
1277 {
1278   return (reg_class_size[(int) rclass] == 1);
1279 }
1280
1281 /* Determine the debugging unwind mechanism for the target.  */
1282
1283 enum unwind_info_type
1284 default_debug_unwind_info (void)
1285 {
1286   /* If the target wants to force the use of dwarf2 unwind info, let it.  */
1287   /* ??? Change all users to the hook, then poison this.  */
1288 #ifdef DWARF2_FRAME_INFO
1289   if (DWARF2_FRAME_INFO)
1290     return UI_DWARF2;
1291 #endif
1292
1293   /* Otherwise, only turn it on if dwarf2 debugging is enabled.  */
1294 #ifdef DWARF2_DEBUGGING_INFO
1295   if (write_symbols == DWARF2_DEBUG || write_symbols == VMS_AND_DWARF2_DEBUG)
1296     return UI_DWARF2;
1297 #endif
1298
1299   return UI_NONE;
1300 }
1301
1302 /* Determine the exception handling mechanism for the target.  */
1303
1304 enum unwind_info_type
1305 default_except_unwind_info (void)
1306 {
1307   /* ??? Change the one user to the hook, then poison this.  */
1308 #ifdef MUST_USE_SJLJ_EXCEPTIONS
1309   if (MUST_USE_SJLJ_EXCEPTIONS)
1310     return UI_SJLJ;
1311 #endif
1312
1313   /* Obey the configure switch to turn on sjlj exceptions.  */
1314 #ifdef CONFIG_SJLJ_EXCEPTIONS
1315   if (CONFIG_SJLJ_EXCEPTIONS)
1316     return UI_SJLJ;
1317 #endif
1318
1319   /* ??? Change all users to the hook, then poison this.  */
1320 #ifdef DWARF2_UNWIND_INFO
1321   if (DWARF2_UNWIND_INFO)
1322     return UI_DWARF2;
1323 #endif
1324
1325   return UI_SJLJ;
1326 }
1327
1328 /* To be used by targets that force dwarf2 unwind enabled.  */
1329
1330 enum unwind_info_type
1331 dwarf2_except_unwind_info (void)
1332 {
1333   /* Obey the configure switch to turn on sjlj exceptions.  */
1334 #ifdef CONFIG_SJLJ_EXCEPTIONS
1335   if (CONFIG_SJLJ_EXCEPTIONS)
1336     return UI_SJLJ;
1337 #endif
1338
1339   return UI_DWARF2;
1340 }
1341
1342 /* To be used by targets that force sjlj unwind enabled.  */
1343
1344 enum unwind_info_type
1345 sjlj_except_unwind_info (void)
1346 {
1347   return UI_SJLJ;
1348 }
1349
1350 /* To be used by targets where reg_raw_mode doesn't return the right
1351    mode for registers used in apply_builtin_return and apply_builtin_arg.  */
1352
1353 enum machine_mode
1354 default_get_reg_raw_mode(int regno)
1355 {
1356   return reg_raw_mode[regno];
1357 }
1358
1359 const struct default_options empty_optimization_table[] =
1360   {
1361     { OPT_LEVELS_NONE, 0, NULL, 0 }
1362   };
1363
1364 #include "gt-targhooks.h"