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 "toplev.h"
  60 #include "function.h"
  61 #include "target.h"
  62 #include "tm_p.h"
  63 #include "target-def.h"
  64 #include "ggc.h"
  65 #include "hard-reg-set.h"
  66 #include "reload.h"
  67 #include "optabs.h"
  68 #include "recog.h"
  69
  70
  71 bool
  72 default_legitimate_address_p (enum machine_mode mode ATTRIBUTE_UNUSED,
  73                               rtx addr ATTRIBUTE_UNUSED,
  74                               bool strict ATTRIBUTE_UNUSED)
  75 {
  76 #ifdef GO_IF_LEGITIMATE_ADDRESS
  77   /* Defer to the old implementation using a goto.  */
  78   if (strict)
  79     return strict_memory_address_p (mode, addr);
  80   else
  81     return memory_address_p (mode, addr);
  82 #else
  83   gcc_unreachable ();
  84 #endif
  85 }
  86
  87 void
  88 default_external_libcall (rtx fun ATTRIBUTE_UNUSED)
  89 {
  90 #ifdef ASM_OUTPUT_EXTERNAL_LIBCALL
  91   ASM_OUTPUT_EXTERNAL_LIBCALL(asm_out_file, fun);
  92 #endif
  93 }
  94
  95 int
  96 default_unspec_may_trap_p (const_rtx x, unsigned flags)
  97 {
  98   int i;
  99
 100   if (GET_CODE (x) == UNSPEC_VOLATILE
 101       /* Any floating arithmetic may trap.  */
 102       || (SCALAR_FLOAT_MODE_P (GET_MODE (x))
 103           && flag_trapping_math))
 104     return 1;
 105
 106   for (i = 0; i < XVECLEN (x, 0); ++i)
 107     {
 108       if (may_trap_p_1 (XVECEXP (x, 0, i), flags))
 109         return 1;
 110     }
 111
 112   return 0;
 113 }
 114
 115 enum machine_mode
 116 default_promote_function_mode (const_tree type ATTRIBUTE_UNUSED,
 117                                enum machine_mode mode,
 118                                int *punsignedp ATTRIBUTE_UNUSED,
 119                                const_tree funtype ATTRIBUTE_UNUSED,
 120                                int for_return ATTRIBUTE_UNUSED)
 121 {
 122   if (for_return == 2)
 123     return promote_mode (type, mode, punsignedp);
 124   return mode;
 125 }
 126
 127 enum machine_mode
 128 default_promote_function_mode_always_promote (const_tree type,
 129                                               enum machine_mode mode,
 130                                               int *punsignedp,
 131                                               const_tree funtype ATTRIBUTE_UNUSED,
 132                                               int for_return ATTRIBUTE_UNUSED)
 133 {
 134   return promote_mode (type, mode, punsignedp);
 135 }
 136
 137
 138 enum machine_mode
 139 default_cc_modes_compatible (enum machine_mode m1, enum machine_mode m2)
 140 {
 141   if (m1 == m2)
 142     return m1;
 143   return VOIDmode;
 144 }
 145
 146 bool
 147 default_return_in_memory (const_tree type,
 148                           const_tree fntype ATTRIBUTE_UNUSED)
 149 {
 150   return (TYPE_MODE (type) == BLKmode);
 151 }
 152
 153 rtx
 154 default_legitimize_address (rtx x, rtx orig_x ATTRIBUTE_UNUSED,
 155                             enum machine_mode mode ATTRIBUTE_UNUSED)
 156 {
 157   return x;
 158 }
 159
 160 rtx
 161 default_expand_builtin_saveregs (void)
 162 {
 163   error ("__builtin_saveregs not supported by this target");
 164   return const0_rtx;
 165 }
 166
 167 void
 168 default_setup_incoming_varargs (CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
 169                                 enum machine_mode mode ATTRIBUTE_UNUSED,
 170                                 tree type ATTRIBUTE_UNUSED,
 171                                 int *pretend_arg_size ATTRIBUTE_UNUSED,
 172                                 int second_time ATTRIBUTE_UNUSED)
 173 {
 174 }
 175
 176 /* The default implementation of TARGET_BUILTIN_SETJMP_FRAME_VALUE.  */
 177
 178 rtx
 179 default_builtin_setjmp_frame_value (void)
 180 {
 181   return virtual_stack_vars_rtx;
 182 }
 183
 184 /* Generic hook that takes a CUMULATIVE_ARGS pointer and returns false.  */
 185
 186 bool
 187 hook_bool_CUMULATIVE_ARGS_false (CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED)
 188 {
 189   return false;
 190 }
 191
 192 bool
 193 default_pretend_outgoing_varargs_named (CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED)
 194 {
 195   return (targetm.calls.setup_incoming_varargs
 196           != default_setup_incoming_varargs);
 197 }
 198
 199 enum machine_mode
 200 default_eh_return_filter_mode (void)
 201 {
 202   return targetm.unwind_word_mode ();
 203 }
 204
 205 enum machine_mode
 206 default_libgcc_cmp_return_mode (void)
 207 {
 208   return word_mode;
 209 }
 210
 211 enum machine_mode
 212 default_libgcc_shift_count_mode (void)
 213 {
 214   return word_mode;
 215 }
 216
 217 enum machine_mode
 218 default_unwind_word_mode (void)
 219 {
 220   return word_mode;
 221 }
 222
 223 /* The default implementation of TARGET_SHIFT_TRUNCATION_MASK.  */
 224
 225 unsigned HOST_WIDE_INT
 226 default_shift_truncation_mask (enum machine_mode mode)
 227 {
 228   return SHIFT_COUNT_TRUNCATED ? GET_MODE_BITSIZE (mode) - 1 : 0;
 229 }
 230
 231 /* The default implementation of TARGET_MIN_DIVISIONS_FOR_RECIP_MUL.  */
 232
 233 unsigned int
 234 default_min_divisions_for_recip_mul (enum machine_mode mode ATTRIBUTE_UNUSED)
 235 {
 236   return have_insn_for (DIV, mode) ? 3 : 2;
 237 }
 238
 239 /* The default implementation of TARGET_MODE_REP_EXTENDED.  */
 240
 241 int
 242 default_mode_rep_extended (enum machine_mode mode ATTRIBUTE_UNUSED,
 243                            enum machine_mode mode_rep ATTRIBUTE_UNUSED)
 244 {
 245   return UNKNOWN;
 246 }
 247
 248 /* Generic hook that takes a CUMULATIVE_ARGS pointer and returns true.  */
 249
 250 bool
 251 hook_bool_CUMULATIVE_ARGS_true (CUMULATIVE_ARGS * a ATTRIBUTE_UNUSED)
 252 {
 253   return true;
 254 }
 255
 256 /* Return machine mode for non-standard suffix
 257    or VOIDmode if non-standard suffixes are unsupported.  */
 258 enum machine_mode
 259 default_mode_for_suffix (char suffix ATTRIBUTE_UNUSED)
 260 {
 261   return VOIDmode;
 262 }
 263
 264 /* The generic C++ ABI specifies this is a 64-bit value.  */
 265 tree
 266 default_cxx_guard_type (void)
 267 {
 268   return long_long_integer_type_node;
 269 }
 270
 271
 272 /* Returns the size of the cookie to use when allocating an array
 273    whose elements have the indicated TYPE.  Assumes that it is already
 274    known that a cookie is needed.  */
 275
 276 tree
 277 default_cxx_get_cookie_size (tree type)
 278 {
 279   tree cookie_size;
 280
 281   /* We need to allocate an additional max (sizeof (size_t), alignof
 282      (true_type)) bytes.  */
 283   tree sizetype_size;
 284   tree type_align;
 285
 286   sizetype_size = size_in_bytes (sizetype);
 287   type_align = size_int (TYPE_ALIGN_UNIT (type));
 288   if (INT_CST_LT_UNSIGNED (type_align, sizetype_size))
 289     cookie_size = sizetype_size;
 290   else
 291     cookie_size = type_align;
 292
 293   return cookie_size;
 294 }
 295
 296 /* Return true if a parameter must be passed by reference.  This version
 297    of the TARGET_PASS_BY_REFERENCE hook uses just MUST_PASS_IN_STACK.  */
 298
 299 bool
 300 hook_pass_by_reference_must_pass_in_stack (CUMULATIVE_ARGS *c ATTRIBUTE_UNUSED,
 301         enum machine_mode mode ATTRIBUTE_UNUSED, const_tree type ATTRIBUTE_UNUSED,
 302         bool named_arg ATTRIBUTE_UNUSED)
 303 {
 304   return targetm.calls.must_pass_in_stack (mode, type);
 305 }
 306
 307 /* Return true if a parameter follows callee copies conventions.  This
 308    version of the hook is true for all named arguments.  */
 309
 310 bool
 311 hook_callee_copies_named (CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
 312                           enum machine_mode mode ATTRIBUTE_UNUSED,
 313                           const_tree type ATTRIBUTE_UNUSED, bool named)
 314 {
 315   return named;
 316 }
 317
 318 /* Emit any directives required to unwind this instruction.  */
 319
 320 void
 321 default_unwind_emit (FILE * stream ATTRIBUTE_UNUSED,
 322                      rtx insn ATTRIBUTE_UNUSED)
 323 {
 324   /* Should never happen.  */
 325   gcc_unreachable ();
 326 }
 327
 328 /* Emit to STREAM the assembler syntax for insn operand X.  */
 329
 330 void
 331 default_print_operand (FILE *stream ATTRIBUTE_UNUSED, rtx x ATTRIBUTE_UNUSED,
 332                        int code ATTRIBUTE_UNUSED)
 333 {
 334 #ifdef PRINT_OPERAND
 335   PRINT_OPERAND (stream, x, code);
 336 #else
 337   gcc_unreachable ();
 338 #endif
 339 }
 340
 341 /* Emit to STREAM the assembler syntax for an insn operand whose memory
 342    address is X.  */
 343
 344 void
 345 default_print_operand_address (FILE *stream ATTRIBUTE_UNUSED,
 346                                rtx x ATTRIBUTE_UNUSED)
 347 {
 348 #ifdef PRINT_OPERAND_ADDRESS
 349   PRINT_OPERAND_ADDRESS (stream, x);
 350 #else
 351   gcc_unreachable ();
 352 #endif
 353 }
 354
 355 /* Return true if CODE is a valid punctuation character for the
 356    `print_operand' hook.  */
 357
 358 bool
 359 default_print_operand_punct_valid_p (unsigned char code ATTRIBUTE_UNUSED)
 360 {
 361 #ifdef PRINT_OPERAND_PUNCT_VALID_P
 362   return PRINT_OPERAND_PUNCT_VALID_P (code);
 363 #else
 364   return false;
 365 #endif
 366 }
 367
 368 /* True if MODE is valid for the target.  By "valid", we mean able to
 369    be manipulated in non-trivial ways.  In particular, this means all
 370    the arithmetic is supported.
 371
 372    By default we guess this means that any C type is supported.  If
 373    we can't map the mode back to a type that would be available in C,
 374    then reject it.  Special case, here, is the double-word arithmetic
 375    supported by optabs.c.  */
 376
 377 bool
 378 default_scalar_mode_supported_p (enum machine_mode mode)
 379 {
 380   int precision = GET_MODE_PRECISION (mode);
 381
 382   switch (GET_MODE_CLASS (mode))
 383     {
 384     case MODE_PARTIAL_INT:
 385     case MODE_INT:
 386       if (precision == CHAR_TYPE_SIZE)
 387         return true;
 388       if (precision == SHORT_TYPE_SIZE)
 389         return true;
 390       if (precision == INT_TYPE_SIZE)
 391         return true;
 392       if (precision == LONG_TYPE_SIZE)
 393         return true;
 394       if (precision == LONG_LONG_TYPE_SIZE)
 395         return true;
 396       if (precision == 2 * BITS_PER_WORD)
 397         return true;
 398       return false;
 399
 400     case MODE_FLOAT:
 401       if (precision == FLOAT_TYPE_SIZE)
 402         return true;
 403       if (precision == DOUBLE_TYPE_SIZE)
 404         return true;
 405       if (precision == LONG_DOUBLE_TYPE_SIZE)
 406         return true;
 407       return false;
 408
 409     case MODE_DECIMAL_FLOAT:
 410     case MODE_FRACT:
 411     case MODE_UFRACT:
 412     case MODE_ACCUM:
 413     case MODE_UACCUM:
 414       return false;
 415
 416     default:
 417       gcc_unreachable ();
 418     }
 419 }
 420
 421 /* True if the target supports decimal floating point.  */
 422
 423 bool
 424 default_decimal_float_supported_p (void)
 425 {
 426   return ENABLE_DECIMAL_FLOAT;
 427 }
 428
 429 /* True if the target supports fixed-point arithmetic.  */
 430
 431 bool
 432 default_fixed_point_supported_p (void)
 433 {
 434   return ENABLE_FIXED_POINT;
 435 }
 436
 437 /* NULL if INSN insn is valid within a low-overhead loop, otherwise returns
 438    an error message.
 439
 440    This function checks whether a given INSN is valid within a low-overhead
 441    loop.  If INSN is invalid it returns the reason for that, otherwise it
 442    returns NULL. A called function may clobber any special registers required
 443    for low-overhead looping. Additionally, some targets (eg, PPC) use the count
 444    register for branch on table instructions. We reject the doloop pattern in
 445    these cases.  */
 446
 447 const char *
 448 default_invalid_within_doloop (const_rtx insn)
 449 {
 450   if (CALL_P (insn))
 451     return "Function call in loop.";
 452
 453   if (JUMP_TABLE_DATA_P (insn))
 454     return "Computed branch in the loop.";
 455
 456   return NULL;
 457 }
 458
 459 /* Mapping of builtin functions to vectorized variants.  */
 460
 461 tree
 462 default_builtin_vectorized_function (tree fndecl ATTRIBUTE_UNUSED,
 463                                      tree type_out ATTRIBUTE_UNUSED,
 464                                      tree type_in ATTRIBUTE_UNUSED)
 465 {
 466   return NULL_TREE;
 467 }
 468
 469 /* Vectorized conversion.  */
 470
 471 tree
 472 default_builtin_vectorized_conversion (unsigned int code ATTRIBUTE_UNUSED,
 473                                        tree dest_type ATTRIBUTE_UNUSED,
 474                                        tree src_type ATTRIBUTE_UNUSED)
 475 {
 476   return NULL_TREE;
 477 }
 478
 479 /* Default vectorizer cost model values.  */
 480
 481 int
 482 default_builtin_vectorization_cost (enum vect_cost_for_stmt type_of_cost)
 483 {
 484   switch (type_of_cost)
 485     {
 486       case scalar_stmt:
 487       case scalar_load:
 488       case scalar_store:
 489       case vector_stmt:
 490       case vector_load:
 491       case vector_store:
 492       case vec_to_scalar:
 493       case scalar_to_vec:
 494       case cond_branch_not_taken:
 495       case vec_perm:
 496         return 1;
 497
 498       case unaligned_load:
 499         return 2;
 500
 501       case cond_branch_taken:
 502         return 3;
 503
 504       default:
 505         gcc_unreachable ();
 506     }
 507 }
 508
 509 /* Reciprocal.  */
 510
 511 tree
 512 default_builtin_reciprocal (unsigned int fn ATTRIBUTE_UNUSED,
 513                             bool md_fn ATTRIBUTE_UNUSED,
 514                             bool sqrt ATTRIBUTE_UNUSED)
 515 {
 516   return NULL_TREE;
 517 }
 518
 519 bool
 520 hook_bool_CUMULATIVE_ARGS_mode_tree_bool_false (
 521         CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
 522         enum machine_mode mode ATTRIBUTE_UNUSED,
 523         const_tree type ATTRIBUTE_UNUSED, bool named ATTRIBUTE_UNUSED)
 524 {
 525   return false;
 526 }
 527
 528 bool
 529 hook_bool_CUMULATIVE_ARGS_mode_tree_bool_true (
 530         CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
 531         enum machine_mode mode ATTRIBUTE_UNUSED,
 532         const_tree type ATTRIBUTE_UNUSED, bool named ATTRIBUTE_UNUSED)
 533 {
 534   return true;
 535 }
 536
 537 int
 538 hook_int_CUMULATIVE_ARGS_mode_tree_bool_0 (
 539         CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
 540         enum machine_mode mode ATTRIBUTE_UNUSED,
 541         tree type ATTRIBUTE_UNUSED, bool named ATTRIBUTE_UNUSED)
 542 {
 543   return 0;
 544 }
 545
 546 void
 547 hook_void_bitmap (bitmap regs ATTRIBUTE_UNUSED)
 548 {
 549 }
 550
 551 const char *
 552 hook_invalid_arg_for_unprototyped_fn (
 553         const_tree typelist ATTRIBUTE_UNUSED,
 554         const_tree funcdecl ATTRIBUTE_UNUSED,
 555         const_tree val ATTRIBUTE_UNUSED)
 556 {
 557   return NULL;
 558 }
 559
 560 /* Initialize the stack protection decls.  */
 561
 562 /* Stack protection related decls living in libgcc.  */
 563 static GTY(()) tree stack_chk_guard_decl;
 564
 565 tree
 566 default_stack_protect_guard (void)
 567 {
 568   tree t = stack_chk_guard_decl;
 569
 570   if (t == NULL)
 571     {
 572       rtx x;
 573
 574       t = build_decl (UNKNOWN_LOCATION,
 575                       VAR_DECL, get_identifier ("__stack_chk_guard"),
 576                       ptr_type_node);
 577       TREE_STATIC (t) = 1;
 578       TREE_PUBLIC (t) = 1;
 579       DECL_EXTERNAL (t) = 1;
 580       TREE_USED (t) = 1;
 581       TREE_THIS_VOLATILE (t) = 1;
 582       DECL_ARTIFICIAL (t) = 1;
 583       DECL_IGNORED_P (t) = 1;
 584
 585       /* Do not share RTL as the declaration is visible outside of
 586          current function.  */
 587       x = DECL_RTL (t);
 588       RTX_FLAG (x, used) = 1;
 589
 590       stack_chk_guard_decl = t;
 591     }
 592
 593   return t;
 594 }
 595
 596 static GTY(()) tree stack_chk_fail_decl;
 597
 598 tree
 599 default_external_stack_protect_fail (void)
 600 {
 601   tree t = stack_chk_fail_decl;
 602
 603   if (t == NULL_TREE)
 604     {
 605       t = build_function_type_list (void_type_node, NULL_TREE);
 606       t = build_decl (UNKNOWN_LOCATION,
 607                       FUNCTION_DECL, get_identifier ("__stack_chk_fail"), t);
 608       TREE_STATIC (t) = 1;
 609       TREE_PUBLIC (t) = 1;
 610       DECL_EXTERNAL (t) = 1;
 611       TREE_USED (t) = 1;
 612       TREE_THIS_VOLATILE (t) = 1;
 613       TREE_NOTHROW (t) = 1;
 614       DECL_ARTIFICIAL (t) = 1;
 615       DECL_IGNORED_P (t) = 1;
 616       DECL_VISIBILITY (t) = VISIBILITY_DEFAULT;
 617       DECL_VISIBILITY_SPECIFIED (t) = 1;
 618
 619       stack_chk_fail_decl = t;
 620     }
 621
 622   return build_call_expr (t, 0);
 623 }
 624
 625 tree
 626 default_hidden_stack_protect_fail (void)
 627 {
 628 #ifndef HAVE_GAS_HIDDEN
 629   return default_external_stack_protect_fail ();
 630 #else
 631   tree t = stack_chk_fail_decl;
 632
 633   if (!flag_pic)
 634     return default_external_stack_protect_fail ();
 635
 636   if (t == NULL_TREE)
 637     {
 638       t = build_function_type_list (void_type_node, NULL_TREE);
 639       t = build_decl (UNKNOWN_LOCATION, FUNCTION_DECL,
 640                       get_identifier ("__stack_chk_fail_local"), t);
 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       TREE_NOTHROW (t) = 1;
 647       DECL_ARTIFICIAL (t) = 1;
 648       DECL_IGNORED_P (t) = 1;
 649       DECL_VISIBILITY_SPECIFIED (t) = 1;
 650       DECL_VISIBILITY (t) = VISIBILITY_HIDDEN;
 651
 652       stack_chk_fail_decl = t;
 653     }
 654
 655   return build_call_expr (t, 0);
 656 #endif
 657 }
 658
 659 bool
 660 hook_bool_const_rtx_commutative_p (const_rtx x,
 661                                    int outer_code ATTRIBUTE_UNUSED)
 662 {
 663   return COMMUTATIVE_P (x);
 664 }
 665
 666 rtx
 667 default_function_value (const_tree ret_type ATTRIBUTE_UNUSED,
 668                         const_tree fn_decl_or_type,
 669                         bool outgoing ATTRIBUTE_UNUSED)
 670 {
 671   /* The old interface doesn't handle receiving the function type.  */
 672   if (fn_decl_or_type
 673       && !DECL_P (fn_decl_or_type))
 674     fn_decl_or_type = NULL;
 675
 676 #ifdef FUNCTION_OUTGOING_VALUE
 677   if (outgoing)
 678     return FUNCTION_OUTGOING_VALUE (ret_type, fn_decl_or_type);
 679 #endif
 680
 681 #ifdef FUNCTION_VALUE
 682   return FUNCTION_VALUE (ret_type, fn_decl_or_type);
 683 #else
 684   gcc_unreachable ();
 685 #endif
 686 }
 687
 688 rtx
 689 default_libcall_value (enum machine_mode mode ATTRIBUTE_UNUSED,
 690                        const_rtx fun ATTRIBUTE_UNUSED)
 691 {
 692 #ifdef LIBCALL_VALUE
 693   return LIBCALL_VALUE (mode);
 694 #else
 695   gcc_unreachable ();
 696 #endif
 697 }
 698
 699 /* The default hook for TARGET_FUNCTION_VALUE_REGNO_P.  */
 700
 701 bool
 702 default_function_value_regno_p (const unsigned int regno ATTRIBUTE_UNUSED)
 703 {
 704 #ifdef FUNCTION_VALUE_REGNO_P
 705   return FUNCTION_VALUE_REGNO_P (regno);
 706 #else
 707   gcc_unreachable ();
 708 #endif
 709 }
 710
 711 rtx
 712 default_internal_arg_pointer (void)
 713 {
 714   /* If the reg that the virtual arg pointer will be translated into is
 715      not a fixed reg or is the stack pointer, make a copy of the virtual
 716      arg pointer, and address parms via the copy.  The frame pointer is
 717      considered fixed even though it is not marked as such.  */
 718   if ((ARG_POINTER_REGNUM == STACK_POINTER_REGNUM
 719        || ! (fixed_regs[ARG_POINTER_REGNUM]
 720              || ARG_POINTER_REGNUM == FRAME_POINTER_REGNUM)))
 721     return copy_to_reg (virtual_incoming_args_rtx);
 722   else
 723     return virtual_incoming_args_rtx;
 724 }
 725
 726 rtx
 727 default_static_chain (const_tree fndecl, bool incoming_p)
 728 {
 729   if (!DECL_STATIC_CHAIN (fndecl))
 730     return NULL;
 731
 732   if (incoming_p)
 733     {
 734 #ifdef STATIC_CHAIN_INCOMING_REGNUM
 735       return gen_rtx_REG (Pmode, STATIC_CHAIN_INCOMING_REGNUM);
 736 #endif
 737     }
 738
 739 #ifdef STATIC_CHAIN_REGNUM
 740   return gen_rtx_REG (Pmode, STATIC_CHAIN_REGNUM);
 741 #endif
 742
 743   {
 744     static bool issued_error;
 745     if (!issued_error)
 746       {
 747         issued_error = true;
 748         sorry ("nested functions not supported on this target");
 749       }
 750
 751     /* It really doesn't matter what we return here, so long at it
 752        doesn't cause the rest of the compiler to crash.  */
 753     return gen_rtx_MEM (Pmode, stack_pointer_rtx);
 754   }
 755 }
 756
 757 void
 758 default_trampoline_init (rtx ARG_UNUSED (m_tramp), tree ARG_UNUSED (t_func),
 759                          rtx ARG_UNUSED (r_chain))
 760 {
 761   sorry ("nested function trampolines not supported on this target");
 762 }
 763
 764 enum reg_class
 765 default_branch_target_register_class (void)
 766 {
 767   return NO_REGS;
 768 }
 769
 770 #ifdef IRA_COVER_CLASSES
 771 const enum reg_class *
 772 default_ira_cover_classes (void)
 773 {
 774   static enum reg_class classes[] = IRA_COVER_CLASSES;
 775   return classes;
 776 }
 777 #endif
 778
 779 enum reg_class
 780 default_secondary_reload (bool in_p ATTRIBUTE_UNUSED, rtx x ATTRIBUTE_UNUSED,
 781                           enum reg_class reload_class ATTRIBUTE_UNUSED,
 782                           enum machine_mode reload_mode ATTRIBUTE_UNUSED,
 783                           secondary_reload_info *sri)
 784 {
 785   enum reg_class rclass = NO_REGS;
 786
 787   if (sri->prev_sri && sri->prev_sri->t_icode != CODE_FOR_nothing)
 788     {
 789       sri->icode = sri->prev_sri->t_icode;
 790       return NO_REGS;
 791     }
 792 #ifdef SECONDARY_INPUT_RELOAD_CLASS
 793   if (in_p)
 794     rclass = SECONDARY_INPUT_RELOAD_CLASS (reload_class, reload_mode, x);
 795 #endif
 796 #ifdef SECONDARY_OUTPUT_RELOAD_CLASS
 797   if (! in_p)
 798     rclass = SECONDARY_OUTPUT_RELOAD_CLASS (reload_class, reload_mode, x);
 799 #endif
 800   if (rclass != NO_REGS)
 801     {
 802       enum insn_code icode = (in_p ? reload_in_optab[(int) reload_mode]
 803                               : reload_out_optab[(int) reload_mode]);
 804
 805       if (icode != CODE_FOR_nothing
 806           && insn_data[(int) icode].operand[in_p].predicate
 807           && ! insn_data[(int) icode].operand[in_p].predicate (x, reload_mode))
 808         icode = CODE_FOR_nothing;
 809       else if (icode != CODE_FOR_nothing)
 810         {
 811           const char *insn_constraint, *scratch_constraint;
 812           char insn_letter, scratch_letter;
 813           enum reg_class insn_class, scratch_class;
 814
 815           gcc_assert (insn_data[(int) icode].n_operands == 3);
 816           insn_constraint = insn_data[(int) icode].operand[!in_p].constraint;
 817           if (!*insn_constraint)
 818             insn_class = ALL_REGS;
 819           else
 820             {
 821               if (in_p)
 822                 {
 823                   gcc_assert (*insn_constraint == '=');
 824                   insn_constraint++;
 825                 }
 826               insn_letter = *insn_constraint;
 827               insn_class
 828                 = (insn_letter == 'r' ? GENERAL_REGS
 829                    : REG_CLASS_FROM_CONSTRAINT ((unsigned char) insn_letter,
 830                                                 insn_constraint));
 831               gcc_assert (insn_class != NO_REGS);
 832             }
 833
 834           scratch_constraint = insn_data[(int) icode].operand[2].constraint;
 835           /* The scratch register's constraint must start with "=&",
 836              except for an input reload, where only "=" is necessary,
 837              and where it might be beneficial to re-use registers from
 838              the input.  */
 839           gcc_assert (scratch_constraint[0] == '='
 840                       && (in_p || scratch_constraint[1] == '&'));
 841           scratch_constraint++;
 842           if (*scratch_constraint == '&')
 843             scratch_constraint++;
 844           scratch_letter = *scratch_constraint;
 845           scratch_class
 846             = (scratch_letter == 'r' ? GENERAL_REGS
 847                : REG_CLASS_FROM_CONSTRAINT ((unsigned char) scratch_letter,
 848                                             scratch_constraint));
 849
 850           if (reg_class_subset_p (reload_class, insn_class))
 851             {
 852               gcc_assert (scratch_class == rclass);
 853               rclass = NO_REGS;
 854             }
 855           else
 856             rclass = insn_class;
 857
 858         }
 859       if (rclass == NO_REGS)
 860         sri->icode = icode;
 861       else
 862         sri->t_icode = icode;
 863     }
 864   return rclass;
 865 }
 866
 867 bool
 868 default_handle_c_option (size_t code ATTRIBUTE_UNUSED,
 869                          const char *arg ATTRIBUTE_UNUSED,
 870                          int value ATTRIBUTE_UNUSED)
 871 {
 872   return false;
 873 }
 874
 875 /* By default, if flag_pic is true, then neither local nor global relocs
 876    should be placed in readonly memory.  */
 877
 878 int
 879 default_reloc_rw_mask (void)
 880 {
 881   return flag_pic ? 3 : 0;
 882 }
 883
 884 /* By default, do no modification. */
 885 tree default_mangle_decl_assembler_name (tree decl ATTRIBUTE_UNUSED,
 886                                          tree id)
 887 {
 888    return id;
 889 }
 890
 891 bool
 892 default_builtin_vector_alignment_reachable (const_tree type, bool is_packed)
 893 {
 894   if (is_packed)
 895     return false;
 896
 897   /* Assuming that types whose size is > pointer-size are not guaranteed to be
 898      naturally aligned.  */
 899   if (tree_int_cst_compare (TYPE_SIZE (type), bitsize_int (POINTER_SIZE)) > 0)
 900     return false;
 901
 902   /* Assuming that types whose size is <= pointer-size
 903      are naturally aligned.  */
 904   return true;
 905 }
 906
 907 /* By default, assume that a target supports any factor of misalignment
 908    memory access if it supports movmisalign patten.
 909    is_packed is true if the memory access is defined in a packed struct.  */
 910 bool
 911 default_builtin_support_vector_misalignment (enum machine_mode mode,
 912                                              const_tree type
 913                                              ATTRIBUTE_UNUSED,
 914                                              int misalignment
 915                                              ATTRIBUTE_UNUSED,
 916                                              bool is_packed
 917                                              ATTRIBUTE_UNUSED)
 918 {
 919   if (optab_handler (movmisalign_optab, mode)->insn_code != CODE_FOR_nothing)
 920     return true;
 921   return false;
 922 }
 923
 924 /* Determine whether or not a pointer mode is valid. Assume defaults
 925    of ptr_mode or Pmode - can be overridden.  */
 926 bool
 927 default_valid_pointer_mode (enum machine_mode mode)
 928 {
 929   return (mode == ptr_mode || mode == Pmode);
 930 }
 931
 932 /* Return the mode for a pointer to a given ADDRSPACE, defaulting to ptr_mode
 933    for the generic address space only.  */
 934
 935 enum machine_mode
 936 default_addr_space_pointer_mode (addr_space_t addrspace ATTRIBUTE_UNUSED)
 937 {
 938   gcc_assert (ADDR_SPACE_GENERIC_P (addrspace));
 939   return ptr_mode;
 940 }
 941
 942 /* Return the mode for an address in a given ADDRSPACE, defaulting to Pmode
 943    for the generic address space only.  */
 944
 945 enum machine_mode
 946 default_addr_space_address_mode (addr_space_t addrspace ATTRIBUTE_UNUSED)
 947 {
 948   gcc_assert (ADDR_SPACE_GENERIC_P (addrspace));
 949   return Pmode;
 950 }
 951
 952 /* Named address space version of valid_pointer_mode.  */
 953
 954 bool
 955 default_addr_space_valid_pointer_mode (enum machine_mode mode, addr_space_t as)
 956 {
 957   if (!ADDR_SPACE_GENERIC_P (as))
 958     return (mode == targetm.addr_space.pointer_mode (as)
 959             || mode == targetm.addr_space.address_mode (as));
 960
 961   return targetm.valid_pointer_mode (mode);
 962 }
 963
 964 /* Some places still assume that all pointer or address modes are the
 965    standard Pmode and ptr_mode.  These optimizations become invalid if
 966    the target actually supports multiple different modes.  For now,
 967    we disable such optimizations on such targets, using this function.  */
 968
 969 bool
 970 target_default_pointer_address_modes_p (void)
 971 {
 972   if (targetm.addr_space.address_mode != default_addr_space_address_mode)
 973     return false;
 974   if (targetm.addr_space.pointer_mode != default_addr_space_pointer_mode)
 975     return false;
 976
 977   return true;
 978 }
 979
 980 /* Named address space version of legitimate_address_p.  */
 981
 982 bool
 983 default_addr_space_legitimate_address_p (enum machine_mode mode, rtx mem,
 984                                          bool strict, addr_space_t as)
 985 {
 986   if (!ADDR_SPACE_GENERIC_P (as))
 987     gcc_unreachable ();
 988
 989   return targetm.legitimate_address_p (mode, mem, strict);
 990 }
 991
 992 /* Named address space version of LEGITIMIZE_ADDRESS.  */
 993
 994 rtx
 995 default_addr_space_legitimize_address (rtx x, rtx oldx,
 996                                        enum machine_mode mode, addr_space_t as)
 997 {
 998   if (!ADDR_SPACE_GENERIC_P (as))
 999     return x;
1000
1001   return targetm.legitimize_address (x, oldx, mode);
1002 }
1003
1004 /* The default hook for determining if one named address space is a subset of
1005    another and to return which address space to use as the common address
1006    space.  */
1007
1008 bool
1009 default_addr_space_subset_p (addr_space_t subset, addr_space_t superset)
1010 {
1011   return (subset == superset);
1012 }
1013
1014 /* The default hook for TARGET_ADDR_SPACE_CONVERT. This hook should never be
1015    called for targets with only a generic address space.  */
1016
1017 rtx
1018 default_addr_space_convert (rtx op ATTRIBUTE_UNUSED,
1019                             tree from_type ATTRIBUTE_UNUSED,
1020                             tree to_type ATTRIBUTE_UNUSED)
1021 {
1022   gcc_unreachable ();
1023 }
1024
1025 bool
1026 default_hard_regno_scratch_ok (unsigned int regno ATTRIBUTE_UNUSED)
1027 {
1028   return true;
1029 }
1030
1031 /* The default implementation of TARGET_MODE_DEPENDENT_ADDRESS_P.  */
1032
1033 bool
1034 default_mode_dependent_address_p (const_rtx addr ATTRIBUTE_UNUSED)
1035 {
1036 #ifdef GO_IF_MODE_DEPENDENT_ADDRESS
1037
1038   GO_IF_MODE_DEPENDENT_ADDRESS (CONST_CAST_RTX (addr), win);
1039   return false;
1040   /* Label `win' might (not) be used via GO_IF_MODE_DEPENDENT_ADDRESS.  */
1041  win: ATTRIBUTE_UNUSED_LABEL
1042   return true;
1043
1044 #else
1045
1046   return false;
1047
1048 #endif
1049 }
1050
1051 bool
1052 default_target_option_valid_attribute_p (tree ARG_UNUSED (fndecl),
1053                                          tree ARG_UNUSED (name),
1054                                          tree ARG_UNUSED (args),
1055                                          int ARG_UNUSED (flags))
1056 {
1057   warning (OPT_Wattributes,
1058            "target attribute is not supported on this machine");
1059
1060   return false;
1061 }
1062
1063 bool
1064 default_target_option_pragma_parse (tree ARG_UNUSED (args),
1065                                     tree ARG_UNUSED (pop_target))
1066 {
1067   warning (OPT_Wpragmas,
1068            "#pragma GCC target is not supported for this machine");
1069
1070   return false;
1071 }
1072
1073 bool
1074 default_target_can_inline_p (tree caller, tree callee)
1075 {
1076   bool ret = false;
1077   tree callee_opts = DECL_FUNCTION_SPECIFIC_TARGET (callee);
1078   tree caller_opts = DECL_FUNCTION_SPECIFIC_TARGET (caller);
1079
1080   /* If callee has no option attributes, then it is ok to inline */
1081   if (!callee_opts)
1082     ret = true;
1083
1084   /* If caller has no option attributes, but callee does then it is not ok to
1085      inline */
1086   else if (!caller_opts)
1087     ret = false;
1088
1089   /* If both caller and callee have attributes, assume that if the pointer is
1090      different, the the two functions have different target options since
1091      build_target_option_node uses a hash table for the options.  */
1092   else
1093     ret = (callee_opts == caller_opts);
1094
1095   return ret;
1096 }
1097
1098 #ifndef HAVE_casesi
1099 # define HAVE_casesi 0
1100 #endif
1101
1102 /* If the machine does not have a case insn that compares the bounds,
1103    this means extra overhead for dispatch tables, which raises the
1104    threshold for using them.  */
1105
1106 unsigned int default_case_values_threshold (void)
1107 {
1108   return (HAVE_casesi ? 4 : 5);
1109 }
1110
1111 bool
1112 default_have_conditional_execution (void)
1113 {
1114 #ifdef HAVE_conditional_execution
1115   return HAVE_conditional_execution;
1116 #else
1117   return false;
1118 #endif
1119 }
1120
1121 /* Compute cost of moving registers to/from memory.  */
1122
1123 int
1124 default_memory_move_cost (enum machine_mode mode ATTRIBUTE_UNUSED,
1125                           enum reg_class rclass ATTRIBUTE_UNUSED,
1126                           bool in ATTRIBUTE_UNUSED)
1127 {
1128 #ifndef MEMORY_MOVE_COST
1129     return (4 + memory_move_secondary_cost (mode, rclass, in));
1130 #else
1131     return MEMORY_MOVE_COST (mode, rclass, in);
1132 #endif
1133 }
1134
1135 #include "gt-targhooks.h"