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 unsigned int
 611 default_function_arg_boundary (enum machine_mode mode ATTRIBUTE_UNUSED,
 612                                const_tree type ATTRIBUTE_UNUSED)
 613 {
 614   return PARM_BOUNDARY;
 615 }
 616
 617 void
 618 hook_void_bitmap (bitmap regs ATTRIBUTE_UNUSED)
 619 {
 620 }
 621
 622 const char *
 623 hook_invalid_arg_for_unprototyped_fn (
 624         const_tree typelist ATTRIBUTE_UNUSED,
 625         const_tree funcdecl ATTRIBUTE_UNUSED,
 626         const_tree val ATTRIBUTE_UNUSED)
 627 {
 628   return NULL;
 629 }
 630
 631 /* Initialize the stack protection decls.  */
 632
 633 /* Stack protection related decls living in libgcc.  */
 634 static GTY(()) tree stack_chk_guard_decl;
 635
 636 tree
 637 default_stack_protect_guard (void)
 638 {
 639   tree t = stack_chk_guard_decl;
 640
 641   if (t == NULL)
 642     {
 643       rtx x;
 644
 645       t = build_decl (UNKNOWN_LOCATION,
 646                       VAR_DECL, get_identifier ("__stack_chk_guard"),
 647                       ptr_type_node);
 648       TREE_STATIC (t) = 1;
 649       TREE_PUBLIC (t) = 1;
 650       DECL_EXTERNAL (t) = 1;
 651       TREE_USED (t) = 1;
 652       TREE_THIS_VOLATILE (t) = 1;
 653       DECL_ARTIFICIAL (t) = 1;
 654       DECL_IGNORED_P (t) = 1;
 655
 656       /* Do not share RTL as the declaration is visible outside of
 657          current function.  */
 658       x = DECL_RTL (t);
 659       RTX_FLAG (x, used) = 1;
 660
 661       stack_chk_guard_decl = t;
 662     }
 663
 664   return t;
 665 }
 666
 667 static GTY(()) tree stack_chk_fail_decl;
 668
 669 tree
 670 default_external_stack_protect_fail (void)
 671 {
 672   tree t = stack_chk_fail_decl;
 673
 674   if (t == NULL_TREE)
 675     {
 676       t = build_function_type_list (void_type_node, NULL_TREE);
 677       t = build_decl (UNKNOWN_LOCATION,
 678                       FUNCTION_DECL, get_identifier ("__stack_chk_fail"), t);
 679       TREE_STATIC (t) = 1;
 680       TREE_PUBLIC (t) = 1;
 681       DECL_EXTERNAL (t) = 1;
 682       TREE_USED (t) = 1;
 683       TREE_THIS_VOLATILE (t) = 1;
 684       TREE_NOTHROW (t) = 1;
 685       DECL_ARTIFICIAL (t) = 1;
 686       DECL_IGNORED_P (t) = 1;
 687       DECL_VISIBILITY (t) = VISIBILITY_DEFAULT;
 688       DECL_VISIBILITY_SPECIFIED (t) = 1;
 689
 690       stack_chk_fail_decl = t;
 691     }
 692
 693   return build_call_expr (t, 0);
 694 }
 695
 696 tree
 697 default_hidden_stack_protect_fail (void)
 698 {
 699 #ifndef HAVE_GAS_HIDDEN
 700   return default_external_stack_protect_fail ();
 701 #else
 702   tree t = stack_chk_fail_decl;
 703
 704   if (!flag_pic)
 705     return default_external_stack_protect_fail ();
 706
 707   if (t == NULL_TREE)
 708     {
 709       t = build_function_type_list (void_type_node, NULL_TREE);
 710       t = build_decl (UNKNOWN_LOCATION, FUNCTION_DECL,
 711                       get_identifier ("__stack_chk_fail_local"), t);
 712       TREE_STATIC (t) = 1;
 713       TREE_PUBLIC (t) = 1;
 714       DECL_EXTERNAL (t) = 1;
 715       TREE_USED (t) = 1;
 716       TREE_THIS_VOLATILE (t) = 1;
 717       TREE_NOTHROW (t) = 1;
 718       DECL_ARTIFICIAL (t) = 1;
 719       DECL_IGNORED_P (t) = 1;
 720       DECL_VISIBILITY_SPECIFIED (t) = 1;
 721       DECL_VISIBILITY (t) = VISIBILITY_HIDDEN;
 722
 723       stack_chk_fail_decl = t;
 724     }
 725
 726   return build_call_expr (t, 0);
 727 #endif
 728 }
 729
 730 bool
 731 hook_bool_const_rtx_commutative_p (const_rtx x,
 732                                    int outer_code ATTRIBUTE_UNUSED)
 733 {
 734   return COMMUTATIVE_P (x);
 735 }
 736
 737 rtx
 738 default_function_value (const_tree ret_type ATTRIBUTE_UNUSED,
 739                         const_tree fn_decl_or_type,
 740                         bool outgoing ATTRIBUTE_UNUSED)
 741 {
 742   /* The old interface doesn't handle receiving the function type.  */
 743   if (fn_decl_or_type
 744       && !DECL_P (fn_decl_or_type))
 745     fn_decl_or_type = NULL;
 746
 747 #ifdef FUNCTION_VALUE
 748   return FUNCTION_VALUE (ret_type, fn_decl_or_type);
 749 #else
 750   gcc_unreachable ();
 751 #endif
 752 }
 753
 754 rtx
 755 default_libcall_value (enum machine_mode mode ATTRIBUTE_UNUSED,
 756                        const_rtx fun ATTRIBUTE_UNUSED)
 757 {
 758 #ifdef LIBCALL_VALUE
 759   return LIBCALL_VALUE (mode);
 760 #else
 761   gcc_unreachable ();
 762 #endif
 763 }
 764
 765 /* The default hook for TARGET_FUNCTION_VALUE_REGNO_P.  */
 766
 767 bool
 768 default_function_value_regno_p (const unsigned int regno ATTRIBUTE_UNUSED)
 769 {
 770 #ifdef FUNCTION_VALUE_REGNO_P
 771   return FUNCTION_VALUE_REGNO_P (regno);
 772 #else
 773   gcc_unreachable ();
 774 #endif
 775 }
 776
 777 rtx
 778 default_internal_arg_pointer (void)
 779 {
 780   /* If the reg that the virtual arg pointer will be translated into is
 781      not a fixed reg or is the stack pointer, make a copy of the virtual
 782      arg pointer, and address parms via the copy.  The frame pointer is
 783      considered fixed even though it is not marked as such.  */
 784   if ((ARG_POINTER_REGNUM == STACK_POINTER_REGNUM
 785        || ! (fixed_regs[ARG_POINTER_REGNUM]
 786              || ARG_POINTER_REGNUM == FRAME_POINTER_REGNUM)))
 787     return copy_to_reg (virtual_incoming_args_rtx);
 788   else
 789     return virtual_incoming_args_rtx;
 790 }
 791
 792 rtx
 793 default_static_chain (const_tree fndecl, bool incoming_p)
 794 {
 795   if (!DECL_STATIC_CHAIN (fndecl))
 796     return NULL;
 797
 798   if (incoming_p)
 799     {
 800 #ifdef STATIC_CHAIN_INCOMING_REGNUM
 801       return gen_rtx_REG (Pmode, STATIC_CHAIN_INCOMING_REGNUM);
 802 #endif
 803     }
 804
 805 #ifdef STATIC_CHAIN_REGNUM
 806   return gen_rtx_REG (Pmode, STATIC_CHAIN_REGNUM);
 807 #endif
 808
 809   {
 810     static bool issued_error;
 811     if (!issued_error)
 812       {
 813         issued_error = true;
 814         sorry ("nested functions not supported on this target");
 815       }
 816
 817     /* It really doesn't matter what we return here, so long at it
 818        doesn't cause the rest of the compiler to crash.  */
 819     return gen_rtx_MEM (Pmode, stack_pointer_rtx);
 820   }
 821 }
 822
 823 void
 824 default_trampoline_init (rtx ARG_UNUSED (m_tramp), tree ARG_UNUSED (t_func),
 825                          rtx ARG_UNUSED (r_chain))
 826 {
 827   sorry ("nested function trampolines not supported on this target");
 828 }
 829
 830 int
 831 default_return_pops_args (tree fundecl ATTRIBUTE_UNUSED,
 832                           tree funtype ATTRIBUTE_UNUSED,
 833                           int size ATTRIBUTE_UNUSED)
 834 {
 835   return 0;
 836 }
 837
 838 reg_class_t
 839 default_branch_target_register_class (void)
 840 {
 841   return NO_REGS;
 842 }
 843
 844 #ifdef IRA_COVER_CLASSES
 845 const reg_class_t *
 846 default_ira_cover_classes (void)
 847 {
 848   static reg_class_t classes[] = IRA_COVER_CLASSES;
 849   return classes;
 850 }
 851 #endif
 852
 853 reg_class_t
 854 default_secondary_reload (bool in_p ATTRIBUTE_UNUSED, rtx x ATTRIBUTE_UNUSED,
 855                           reg_class_t reload_class_i ATTRIBUTE_UNUSED,
 856                           enum machine_mode reload_mode ATTRIBUTE_UNUSED,
 857                           secondary_reload_info *sri)
 858 {
 859   enum reg_class rclass = NO_REGS;
 860   enum reg_class reload_class = (enum reg_class) reload_class_i;
 861
 862   if (sri->prev_sri && sri->prev_sri->t_icode != CODE_FOR_nothing)
 863     {
 864       sri->icode = sri->prev_sri->t_icode;
 865       return NO_REGS;
 866     }
 867 #ifdef SECONDARY_INPUT_RELOAD_CLASS
 868   if (in_p)
 869     rclass = SECONDARY_INPUT_RELOAD_CLASS (reload_class, reload_mode, x);
 870 #endif
 871 #ifdef SECONDARY_OUTPUT_RELOAD_CLASS
 872   if (! in_p)
 873     rclass = SECONDARY_OUTPUT_RELOAD_CLASS (reload_class, reload_mode, x);
 874 #endif
 875   if (rclass != NO_REGS)
 876     {
 877       enum insn_code icode
 878         = direct_optab_handler (in_p ? reload_in_optab : reload_out_optab,
 879                                 reload_mode);
 880
 881       if (icode != CODE_FOR_nothing
 882           && insn_data[(int) icode].operand[in_p].predicate
 883           && ! insn_data[(int) icode].operand[in_p].predicate (x, reload_mode))
 884         icode = CODE_FOR_nothing;
 885       else if (icode != CODE_FOR_nothing)
 886         {
 887           const char *insn_constraint, *scratch_constraint;
 888           char insn_letter, scratch_letter;
 889           enum reg_class insn_class, scratch_class;
 890
 891           gcc_assert (insn_data[(int) icode].n_operands == 3);
 892           insn_constraint = insn_data[(int) icode].operand[!in_p].constraint;
 893           if (!*insn_constraint)
 894             insn_class = ALL_REGS;
 895           else
 896             {
 897               if (in_p)
 898                 {
 899                   gcc_assert (*insn_constraint == '=');
 900                   insn_constraint++;
 901                 }
 902               insn_letter = *insn_constraint;
 903               insn_class
 904                 = (insn_letter == 'r' ? GENERAL_REGS
 905                    : REG_CLASS_FROM_CONSTRAINT ((unsigned char) insn_letter,
 906                                                 insn_constraint));
 907               gcc_assert (insn_class != NO_REGS);
 908             }
 909
 910           scratch_constraint = insn_data[(int) icode].operand[2].constraint;
 911           /* The scratch register's constraint must start with "=&",
 912              except for an input reload, where only "=" is necessary,
 913              and where it might be beneficial to re-use registers from
 914              the input.  */
 915           gcc_assert (scratch_constraint[0] == '='
 916                       && (in_p || scratch_constraint[1] == '&'));
 917           scratch_constraint++;
 918           if (*scratch_constraint == '&')
 919             scratch_constraint++;
 920           scratch_letter = *scratch_constraint;
 921           scratch_class
 922             = (scratch_letter == 'r' ? GENERAL_REGS
 923                : REG_CLASS_FROM_CONSTRAINT ((unsigned char) scratch_letter,
 924                                             scratch_constraint));
 925
 926           if (reg_class_subset_p (reload_class, insn_class))
 927             {
 928               gcc_assert (scratch_class == rclass);
 929               rclass = NO_REGS;
 930             }
 931           else
 932             rclass = insn_class;
 933
 934         }
 935       if (rclass == NO_REGS)
 936         sri->icode = icode;
 937       else
 938         sri->t_icode = icode;
 939     }
 940   return rclass;
 941 }
 942
 943 bool
 944 default_handle_c_option (size_t code ATTRIBUTE_UNUSED,
 945                          const char *arg ATTRIBUTE_UNUSED,
 946                          int value ATTRIBUTE_UNUSED)
 947 {
 948   return false;
 949 }
 950
 951 /* By default, if flag_pic is true, then neither local nor global relocs
 952    should be placed in readonly memory.  */
 953
 954 int
 955 default_reloc_rw_mask (void)
 956 {
 957   return flag_pic ? 3 : 0;
 958 }
 959
 960 /* By default, do no modification. */
 961 tree default_mangle_decl_assembler_name (tree decl ATTRIBUTE_UNUSED,
 962                                          tree id)
 963 {
 964    return id;
 965 }
 966
 967 bool
 968 default_builtin_vector_alignment_reachable (const_tree type, bool is_packed)
 969 {
 970   if (is_packed)
 971     return false;
 972
 973   /* Assuming that types whose size is > pointer-size are not guaranteed to be
 974      naturally aligned.  */
 975   if (tree_int_cst_compare (TYPE_SIZE (type), bitsize_int (POINTER_SIZE)) > 0)
 976     return false;
 977
 978   /* Assuming that types whose size is <= pointer-size
 979      are naturally aligned.  */
 980   return true;
 981 }
 982
 983 /* By default, assume that a target supports any factor of misalignment
 984    memory access if it supports movmisalign patten.
 985    is_packed is true if the memory access is defined in a packed struct.  */
 986 bool
 987 default_builtin_support_vector_misalignment (enum machine_mode mode,
 988                                              const_tree type
 989                                              ATTRIBUTE_UNUSED,
 990                                              int misalignment
 991                                              ATTRIBUTE_UNUSED,
 992                                              bool is_packed
 993                                              ATTRIBUTE_UNUSED)
 994 {
 995   if (optab_handler (movmisalign_optab, mode) != CODE_FOR_nothing)
 996     return true;
 997   return false;
 998 }
 999
1000 /* By default, only attempt to parallelize bitwise operations, and
1001    possibly adds/subtracts using bit-twiddling.  */
1002
1003 enum machine_mode
1004 default_preferred_simd_mode (enum machine_mode mode ATTRIBUTE_UNUSED)
1005 {
1006   return word_mode;
1007 }
1008
1009 /* By default only the size derived from the preferred vector mode
1010    is tried.  */
1011
1012 unsigned int
1013 default_autovectorize_vector_sizes (void)
1014 {
1015   return 0;
1016 }
1017
1018 /* Determine whether or not a pointer mode is valid. Assume defaults
1019    of ptr_mode or Pmode - can be overridden.  */
1020 bool
1021 default_valid_pointer_mode (enum machine_mode mode)
1022 {
1023   return (mode == ptr_mode || mode == Pmode);
1024 }
1025
1026 /* Return the mode for a pointer to a given ADDRSPACE, defaulting to ptr_mode
1027    for the generic address space only.  */
1028
1029 enum machine_mode
1030 default_addr_space_pointer_mode (addr_space_t addrspace ATTRIBUTE_UNUSED)
1031 {
1032   gcc_assert (ADDR_SPACE_GENERIC_P (addrspace));
1033   return ptr_mode;
1034 }
1035
1036 /* Return the mode for an address in a given ADDRSPACE, defaulting to Pmode
1037    for the generic address space only.  */
1038
1039 enum machine_mode
1040 default_addr_space_address_mode (addr_space_t addrspace ATTRIBUTE_UNUSED)
1041 {
1042   gcc_assert (ADDR_SPACE_GENERIC_P (addrspace));
1043   return Pmode;
1044 }
1045
1046 /* Named address space version of valid_pointer_mode.  */
1047
1048 bool
1049 default_addr_space_valid_pointer_mode (enum machine_mode mode, addr_space_t as)
1050 {
1051   if (!ADDR_SPACE_GENERIC_P (as))
1052     return (mode == targetm.addr_space.pointer_mode (as)
1053             || mode == targetm.addr_space.address_mode (as));
1054
1055   return targetm.valid_pointer_mode (mode);
1056 }
1057
1058 /* Some places still assume that all pointer or address modes are the
1059    standard Pmode and ptr_mode.  These optimizations become invalid if
1060    the target actually supports multiple different modes.  For now,
1061    we disable such optimizations on such targets, using this function.  */
1062
1063 bool
1064 target_default_pointer_address_modes_p (void)
1065 {
1066   if (targetm.addr_space.address_mode != default_addr_space_address_mode)
1067     return false;
1068   if (targetm.addr_space.pointer_mode != default_addr_space_pointer_mode)
1069     return false;
1070
1071   return true;
1072 }
1073
1074 /* Named address space version of legitimate_address_p.  */
1075
1076 bool
1077 default_addr_space_legitimate_address_p (enum machine_mode mode, rtx mem,
1078                                          bool strict, addr_space_t as)
1079 {
1080   if (!ADDR_SPACE_GENERIC_P (as))
1081     gcc_unreachable ();
1082
1083   return targetm.legitimate_address_p (mode, mem, strict);
1084 }
1085
1086 /* Named address space version of LEGITIMIZE_ADDRESS.  */
1087
1088 rtx
1089 default_addr_space_legitimize_address (rtx x, rtx oldx,
1090                                        enum machine_mode mode, addr_space_t as)
1091 {
1092   if (!ADDR_SPACE_GENERIC_P (as))
1093     return x;
1094
1095   return targetm.legitimize_address (x, oldx, mode);
1096 }
1097
1098 /* The default hook for determining if one named address space is a subset of
1099    another and to return which address space to use as the common address
1100    space.  */
1101
1102 bool
1103 default_addr_space_subset_p (addr_space_t subset, addr_space_t superset)
1104 {
1105   return (subset == superset);
1106 }
1107
1108 /* The default hook for TARGET_ADDR_SPACE_CONVERT. This hook should never be
1109    called for targets with only a generic address space.  */
1110
1111 rtx
1112 default_addr_space_convert (rtx op ATTRIBUTE_UNUSED,
1113                             tree from_type ATTRIBUTE_UNUSED,
1114                             tree to_type ATTRIBUTE_UNUSED)
1115 {
1116   gcc_unreachable ();
1117 }
1118
1119 bool
1120 default_hard_regno_scratch_ok (unsigned int regno ATTRIBUTE_UNUSED)
1121 {
1122   return true;
1123 }
1124
1125 /* The default implementation of TARGET_MODE_DEPENDENT_ADDRESS_P.  */
1126
1127 bool
1128 default_mode_dependent_address_p (const_rtx addr ATTRIBUTE_UNUSED)
1129 {
1130 #ifdef GO_IF_MODE_DEPENDENT_ADDRESS
1131
1132   GO_IF_MODE_DEPENDENT_ADDRESS (CONST_CAST_RTX (addr), win);
1133   return false;
1134   /* Label `win' might (not) be used via GO_IF_MODE_DEPENDENT_ADDRESS.  */
1135  win: ATTRIBUTE_UNUSED_LABEL
1136   return true;
1137
1138 #else
1139
1140   return false;
1141
1142 #endif
1143 }
1144
1145 bool
1146 default_target_option_valid_attribute_p (tree ARG_UNUSED (fndecl),
1147                                          tree ARG_UNUSED (name),
1148                                          tree ARG_UNUSED (args),
1149                                          int ARG_UNUSED (flags))
1150 {
1151   warning (OPT_Wattributes,
1152            "target attribute is not supported on this machine");
1153
1154   return false;
1155 }
1156
1157 bool
1158 default_target_option_pragma_parse (tree ARG_UNUSED (args),
1159                                     tree ARG_UNUSED (pop_target))
1160 {
1161   warning (OPT_Wpragmas,
1162            "#pragma GCC target is not supported for this machine");
1163
1164   return false;
1165 }
1166
1167 bool
1168 default_target_can_inline_p (tree caller, tree callee)
1169 {
1170   bool ret = false;
1171   tree callee_opts = DECL_FUNCTION_SPECIFIC_TARGET (callee);
1172   tree caller_opts = DECL_FUNCTION_SPECIFIC_TARGET (caller);
1173
1174   /* If callee has no option attributes, then it is ok to inline */
1175   if (!callee_opts)
1176     ret = true;
1177
1178   /* If caller has no option attributes, but callee does then it is not ok to
1179      inline */
1180   else if (!caller_opts)
1181     ret = false;
1182
1183   /* If both caller and callee have attributes, assume that if the pointer is
1184      different, the the two functions have different target options since
1185      build_target_option_node uses a hash table for the options.  */
1186   else
1187     ret = (callee_opts == caller_opts);
1188
1189   return ret;
1190 }
1191
1192 #ifndef HAVE_casesi
1193 # define HAVE_casesi 0
1194 #endif
1195
1196 /* If the machine does not have a case insn that compares the bounds,
1197    this means extra overhead for dispatch tables, which raises the
1198    threshold for using them.  */
1199
1200 unsigned int default_case_values_threshold (void)
1201 {
1202   return (HAVE_casesi ? 4 : 5);
1203 }
1204
1205 bool
1206 default_have_conditional_execution (void)
1207 {
1208 #ifdef HAVE_conditional_execution
1209   return HAVE_conditional_execution;
1210 #else
1211   return false;
1212 #endif
1213 }
1214
1215 /* Compute cost of moving registers to/from memory.  */
1216
1217 int
1218 default_memory_move_cost (enum machine_mode mode ATTRIBUTE_UNUSED,
1219                           reg_class_t rclass ATTRIBUTE_UNUSED,
1220                           bool in ATTRIBUTE_UNUSED)
1221 {
1222 #ifndef MEMORY_MOVE_COST
1223     return (4 + memory_move_secondary_cost (mode, (enum reg_class) rclass, in));
1224 #else
1225     return MEMORY_MOVE_COST (mode, (enum reg_class) rclass, in);
1226 #endif
1227 }
1228
1229 /* Compute cost of moving data from a register of class FROM to one of
1230    TO, using MODE.  */
1231
1232 int
1233 default_register_move_cost (enum machine_mode mode ATTRIBUTE_UNUSED,
1234                             reg_class_t from ATTRIBUTE_UNUSED,
1235                             reg_class_t to ATTRIBUTE_UNUSED)
1236 {
1237 #ifndef REGISTER_MOVE_COST
1238   return 2;
1239 #else
1240   return REGISTER_MOVE_COST (mode, (enum reg_class) from, (enum reg_class) to);
1241 #endif
1242 }
1243
1244 bool
1245 default_profile_before_prologue (void)
1246 {
1247 #ifdef PROFILE_BEFORE_PROLOGUE
1248   return true;
1249 #else
1250   return false;
1251 #endif
1252 }
1253
1254 /* The default implementation of TARGET_PREFERRED_RELOAD_CLASS.  */
1255
1256 reg_class_t
1257 default_preferred_reload_class (rtx x ATTRIBUTE_UNUSED,
1258                                 reg_class_t rclass)
1259 {
1260 #ifdef PREFERRED_RELOAD_CLASS
1261   return (reg_class_t) PREFERRED_RELOAD_CLASS (x, (enum reg_class) rclass);
1262 #else
1263   return rclass;
1264 #endif
1265 }
1266
1267 /* The default implementation of TARGET_OUTPUT_PREFERRED_RELOAD_CLASS.  */
1268
1269 reg_class_t
1270 default_preferred_output_reload_class (rtx x ATTRIBUTE_UNUSED,
1271                                        reg_class_t rclass)
1272 {
1273 #ifdef PREFERRED_OUTPUT_RELOAD_CLASS
1274   return PREFERRED_OUTPUT_RELOAD_CLASS (x, (enum reg_class) rclass);
1275 #else
1276   return rclass;
1277 #endif
1278 }
1279
1280 /* The default implementation of TARGET_CLASS_LIKELY_SPILLED_P.  */
1281
1282 bool
1283 default_class_likely_spilled_p (reg_class_t rclass)
1284 {
1285   return (reg_class_size[(int) rclass] == 1);
1286 }
1287
1288 /* Determine the debugging unwind mechanism for the target.  */
1289
1290 enum unwind_info_type
1291 default_debug_unwind_info (void)
1292 {
1293   /* If the target wants to force the use of dwarf2 unwind info, let it.  */
1294   /* ??? Change all users to the hook, then poison this.  */
1295 #ifdef DWARF2_FRAME_INFO
1296   if (DWARF2_FRAME_INFO)
1297     return UI_DWARF2;
1298 #endif
1299
1300   /* Otherwise, only turn it on if dwarf2 debugging is enabled.  */
1301 #ifdef DWARF2_DEBUGGING_INFO
1302   if (write_symbols == DWARF2_DEBUG || write_symbols == VMS_AND_DWARF2_DEBUG)
1303     return UI_DWARF2;
1304 #endif
1305
1306   return UI_NONE;
1307 }
1308
1309 /* Determine the exception handling mechanism for the target.  */
1310
1311 enum unwind_info_type
1312 default_except_unwind_info (struct gcc_options *opts ATTRIBUTE_UNUSED)
1313 {
1314   /* Obey the configure switch to turn on sjlj exceptions.  */
1315 #ifdef CONFIG_SJLJ_EXCEPTIONS
1316   if (CONFIG_SJLJ_EXCEPTIONS)
1317     return UI_SJLJ;
1318 #endif
1319
1320   /* ??? Change all users to the hook, then poison this.  */
1321 #ifdef DWARF2_UNWIND_INFO
1322   if (DWARF2_UNWIND_INFO)
1323     return UI_DWARF2;
1324 #endif
1325
1326   return UI_SJLJ;
1327 }
1328
1329 /* To be used by targets that force dwarf2 unwind enabled.  */
1330
1331 enum unwind_info_type
1332 dwarf2_except_unwind_info (struct gcc_options *opts ATTRIBUTE_UNUSED)
1333 {
1334   /* Obey the configure switch to turn on sjlj exceptions.  */
1335 #ifdef CONFIG_SJLJ_EXCEPTIONS
1336   if (CONFIG_SJLJ_EXCEPTIONS)
1337     return UI_SJLJ;
1338 #endif
1339
1340   return UI_DWARF2;
1341 }
1342
1343 /* To be used by targets that force sjlj unwind enabled.  */
1344
1345 enum unwind_info_type
1346 sjlj_except_unwind_info (struct gcc_options *opts ATTRIBUTE_UNUSED)
1347 {
1348   return UI_SJLJ;
1349 }
1350
1351 /* To be used by targets where reg_raw_mode doesn't return the right
1352    mode for registers used in apply_builtin_return and apply_builtin_arg.  */
1353
1354 enum machine_mode
1355 default_get_reg_raw_mode(int regno)
1356 {
1357   return reg_raw_mode[regno];
1358 }
1359
1360 const struct default_options empty_optimization_table[] =
1361   {
1362     { OPT_LEVELS_NONE, 0, NULL, 0 }
1363   };
1364
1365 #include "gt-targhooks.h"