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 /* True if MODE is valid for the target.  By "valid", we mean able to
 329    be manipulated in non-trivial ways.  In particular, this means all
 330    the arithmetic is supported.
 331
 332    By default we guess this means that any C type is supported.  If
 333    we can't map the mode back to a type that would be available in C,
 334    then reject it.  Special case, here, is the double-word arithmetic
 335    supported by optabs.c.  */
 336
 337 bool
 338 default_scalar_mode_supported_p (enum machine_mode mode)
 339 {
 340   int precision = GET_MODE_PRECISION (mode);
 341
 342   switch (GET_MODE_CLASS (mode))
 343     {
 344     case MODE_PARTIAL_INT:
 345     case MODE_INT:
 346       if (precision == CHAR_TYPE_SIZE)
 347         return true;
 348       if (precision == SHORT_TYPE_SIZE)
 349         return true;
 350       if (precision == INT_TYPE_SIZE)
 351         return true;
 352       if (precision == LONG_TYPE_SIZE)
 353         return true;
 354       if (precision == LONG_LONG_TYPE_SIZE)
 355         return true;
 356       if (precision == 2 * BITS_PER_WORD)
 357         return true;
 358       return false;
 359
 360     case MODE_FLOAT:
 361       if (precision == FLOAT_TYPE_SIZE)
 362         return true;
 363       if (precision == DOUBLE_TYPE_SIZE)
 364         return true;
 365       if (precision == LONG_DOUBLE_TYPE_SIZE)
 366         return true;
 367       return false;
 368
 369     case MODE_DECIMAL_FLOAT:
 370     case MODE_FRACT:
 371     case MODE_UFRACT:
 372     case MODE_ACCUM:
 373     case MODE_UACCUM:
 374       return false;
 375
 376     default:
 377       gcc_unreachable ();
 378     }
 379 }
 380
 381 /* True if the target supports decimal floating point.  */
 382
 383 bool
 384 default_decimal_float_supported_p (void)
 385 {
 386   return ENABLE_DECIMAL_FLOAT;
 387 }
 388
 389 /* True if the target supports fixed-point arithmetic.  */
 390
 391 bool
 392 default_fixed_point_supported_p (void)
 393 {
 394   return ENABLE_FIXED_POINT;
 395 }
 396
 397 /* NULL if INSN insn is valid within a low-overhead loop, otherwise returns
 398    an error message.
 399
 400    This function checks whether a given INSN is valid within a low-overhead
 401    loop.  If INSN is invalid it returns the reason for that, otherwise it
 402    returns NULL. A called function may clobber any special registers required
 403    for low-overhead looping. Additionally, some targets (eg, PPC) use the count
 404    register for branch on table instructions. We reject the doloop pattern in
 405    these cases.  */
 406
 407 const char *
 408 default_invalid_within_doloop (const_rtx insn)
 409 {
 410   if (CALL_P (insn))
 411     return "Function call in loop.";
 412
 413   if (JUMP_TABLE_DATA_P (insn))
 414     return "Computed branch in the loop.";
 415
 416   return NULL;
 417 }
 418
 419 /* Mapping of builtin functions to vectorized variants.  */
 420
 421 tree
 422 default_builtin_vectorized_function (tree fndecl ATTRIBUTE_UNUSED,
 423                                      tree type_out ATTRIBUTE_UNUSED,
 424                                      tree type_in ATTRIBUTE_UNUSED)
 425 {
 426   return NULL_TREE;
 427 }
 428
 429 /* Vectorized conversion.  */
 430
 431 tree
 432 default_builtin_vectorized_conversion (unsigned int code ATTRIBUTE_UNUSED,
 433                                        tree dest_type ATTRIBUTE_UNUSED,
 434                                        tree src_type ATTRIBUTE_UNUSED)
 435 {
 436   return NULL_TREE;
 437 }
 438
 439 /* Reciprocal.  */
 440
 441 tree
 442 default_builtin_reciprocal (unsigned int fn ATTRIBUTE_UNUSED,
 443                             bool md_fn ATTRIBUTE_UNUSED,
 444                             bool sqrt ATTRIBUTE_UNUSED)
 445 {
 446   return NULL_TREE;
 447 }
 448
 449 bool
 450 hook_bool_CUMULATIVE_ARGS_mode_tree_bool_false (
 451         CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
 452         enum machine_mode mode ATTRIBUTE_UNUSED,
 453         const_tree type ATTRIBUTE_UNUSED, bool named ATTRIBUTE_UNUSED)
 454 {
 455   return false;
 456 }
 457
 458 bool
 459 hook_bool_CUMULATIVE_ARGS_mode_tree_bool_true (
 460         CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
 461         enum machine_mode mode ATTRIBUTE_UNUSED,
 462         const_tree type ATTRIBUTE_UNUSED, bool named ATTRIBUTE_UNUSED)
 463 {
 464   return true;
 465 }
 466
 467 int
 468 hook_int_CUMULATIVE_ARGS_mode_tree_bool_0 (
 469         CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
 470         enum machine_mode mode ATTRIBUTE_UNUSED,
 471         tree type ATTRIBUTE_UNUSED, bool named ATTRIBUTE_UNUSED)
 472 {
 473   return 0;
 474 }
 475
 476 void
 477 hook_void_bitmap (bitmap regs ATTRIBUTE_UNUSED)
 478 {
 479 }
 480
 481 const char *
 482 hook_invalid_arg_for_unprototyped_fn (
 483         const_tree typelist ATTRIBUTE_UNUSED,
 484         const_tree funcdecl ATTRIBUTE_UNUSED,
 485         const_tree val ATTRIBUTE_UNUSED)
 486 {
 487   return NULL;
 488 }
 489
 490 /* Initialize the stack protection decls.  */
 491
 492 /* Stack protection related decls living in libgcc.  */
 493 static GTY(()) tree stack_chk_guard_decl;
 494
 495 tree
 496 default_stack_protect_guard (void)
 497 {
 498   tree t = stack_chk_guard_decl;
 499
 500   if (t == NULL)
 501     {
 502       rtx x;
 503
 504       t = build_decl (UNKNOWN_LOCATION,
 505                       VAR_DECL, get_identifier ("__stack_chk_guard"),
 506                       ptr_type_node);
 507       TREE_STATIC (t) = 1;
 508       TREE_PUBLIC (t) = 1;
 509       DECL_EXTERNAL (t) = 1;
 510       TREE_USED (t) = 1;
 511       TREE_THIS_VOLATILE (t) = 1;
 512       DECL_ARTIFICIAL (t) = 1;
 513       DECL_IGNORED_P (t) = 1;
 514
 515       /* Do not share RTL as the declaration is visible outside of
 516          current function.  */
 517       x = DECL_RTL (t);
 518       RTX_FLAG (x, used) = 1;
 519
 520       stack_chk_guard_decl = t;
 521     }
 522
 523   return t;
 524 }
 525
 526 static GTY(()) tree stack_chk_fail_decl;
 527
 528 tree
 529 default_external_stack_protect_fail (void)
 530 {
 531   tree t = stack_chk_fail_decl;
 532
 533   if (t == NULL_TREE)
 534     {
 535       t = build_function_type_list (void_type_node, NULL_TREE);
 536       t = build_decl (UNKNOWN_LOCATION,
 537                       FUNCTION_DECL, get_identifier ("__stack_chk_fail"), t);
 538       TREE_STATIC (t) = 1;
 539       TREE_PUBLIC (t) = 1;
 540       DECL_EXTERNAL (t) = 1;
 541       TREE_USED (t) = 1;
 542       TREE_THIS_VOLATILE (t) = 1;
 543       TREE_NOTHROW (t) = 1;
 544       DECL_ARTIFICIAL (t) = 1;
 545       DECL_IGNORED_P (t) = 1;
 546       DECL_VISIBILITY (t) = VISIBILITY_DEFAULT;
 547       DECL_VISIBILITY_SPECIFIED (t) = 1;
 548
 549       stack_chk_fail_decl = t;
 550     }
 551
 552   return build_call_expr (t, 0);
 553 }
 554
 555 tree
 556 default_hidden_stack_protect_fail (void)
 557 {
 558 #ifndef HAVE_GAS_HIDDEN
 559   return default_external_stack_protect_fail ();
 560 #else
 561   tree t = stack_chk_fail_decl;
 562
 563   if (!flag_pic)
 564     return default_external_stack_protect_fail ();
 565
 566   if (t == NULL_TREE)
 567     {
 568       t = build_function_type_list (void_type_node, NULL_TREE);
 569       t = build_decl (UNKNOWN_LOCATION, FUNCTION_DECL,
 570                       get_identifier ("__stack_chk_fail_local"), t);
 571       TREE_STATIC (t) = 1;
 572       TREE_PUBLIC (t) = 1;
 573       DECL_EXTERNAL (t) = 1;
 574       TREE_USED (t) = 1;
 575       TREE_THIS_VOLATILE (t) = 1;
 576       TREE_NOTHROW (t) = 1;
 577       DECL_ARTIFICIAL (t) = 1;
 578       DECL_IGNORED_P (t) = 1;
 579       DECL_VISIBILITY_SPECIFIED (t) = 1;
 580       DECL_VISIBILITY (t) = VISIBILITY_HIDDEN;
 581
 582       stack_chk_fail_decl = t;
 583     }
 584
 585   return build_call_expr (t, 0);
 586 #endif
 587 }
 588
 589 bool
 590 hook_bool_const_rtx_commutative_p (const_rtx x,
 591                                    int outer_code ATTRIBUTE_UNUSED)
 592 {
 593   return COMMUTATIVE_P (x);
 594 }
 595
 596 rtx
 597 default_function_value (const_tree ret_type ATTRIBUTE_UNUSED,
 598                         const_tree fn_decl_or_type,
 599                         bool outgoing ATTRIBUTE_UNUSED)
 600 {
 601   /* The old interface doesn't handle receiving the function type.  */
 602   if (fn_decl_or_type
 603       && !DECL_P (fn_decl_or_type))
 604     fn_decl_or_type = NULL;
 605
 606 #ifdef FUNCTION_OUTGOING_VALUE
 607   if (outgoing)
 608     return FUNCTION_OUTGOING_VALUE (ret_type, fn_decl_or_type);
 609 #endif
 610
 611 #ifdef FUNCTION_VALUE
 612   return FUNCTION_VALUE (ret_type, fn_decl_or_type);
 613 #else
 614   gcc_unreachable ();
 615 #endif
 616 }
 617
 618 rtx
 619 default_libcall_value (enum machine_mode mode ATTRIBUTE_UNUSED,
 620                        const_rtx fun ATTRIBUTE_UNUSED)
 621 {
 622 #ifdef LIBCALL_VALUE
 623   return LIBCALL_VALUE (mode);
 624 #else
 625   gcc_unreachable ();
 626 #endif
 627 }
 628
 629 /* The default hook for TARGET_FUNCTION_VALUE_REGNO_P.  */
 630
 631 bool
 632 default_function_value_regno_p (const unsigned int regno ATTRIBUTE_UNUSED)
 633 {
 634 #ifdef FUNCTION_VALUE_REGNO_P
 635   return FUNCTION_VALUE_REGNO_P (regno);
 636 #else
 637   gcc_unreachable ();
 638 #endif
 639 }
 640
 641 rtx
 642 default_internal_arg_pointer (void)
 643 {
 644   /* If the reg that the virtual arg pointer will be translated into is
 645      not a fixed reg or is the stack pointer, make a copy of the virtual
 646      arg pointer, and address parms via the copy.  The frame pointer is
 647      considered fixed even though it is not marked as such.  */
 648   if ((ARG_POINTER_REGNUM == STACK_POINTER_REGNUM
 649        || ! (fixed_regs[ARG_POINTER_REGNUM]
 650              || ARG_POINTER_REGNUM == FRAME_POINTER_REGNUM)))
 651     return copy_to_reg (virtual_incoming_args_rtx);
 652   else
 653     return virtual_incoming_args_rtx;
 654 }
 655
 656 rtx
 657 default_static_chain (const_tree fndecl, bool incoming_p)
 658 {
 659   if (!DECL_STATIC_CHAIN (fndecl))
 660     return NULL;
 661
 662   if (incoming_p)
 663     {
 664 #ifdef STATIC_CHAIN_INCOMING_REGNUM
 665       return gen_rtx_REG (Pmode, STATIC_CHAIN_INCOMING_REGNUM);
 666 #endif
 667     }
 668
 669 #ifdef STATIC_CHAIN_REGNUM
 670   return gen_rtx_REG (Pmode, STATIC_CHAIN_REGNUM);
 671 #endif
 672
 673   {
 674     static bool issued_error;
 675     if (!issued_error)
 676       {
 677         issued_error = true;
 678         sorry ("nested functions not supported on this target");
 679       }
 680
 681     /* It really doesn't matter what we return here, so long at it
 682        doesn't cause the rest of the compiler to crash.  */
 683     return gen_rtx_MEM (Pmode, stack_pointer_rtx);
 684   }
 685 }
 686
 687 void
 688 default_trampoline_init (rtx ARG_UNUSED (m_tramp), tree ARG_UNUSED (t_func),
 689                          rtx ARG_UNUSED (r_chain))
 690 {
 691   sorry ("nested function trampolines not supported on this target");
 692 }
 693
 694 enum reg_class
 695 default_branch_target_register_class (void)
 696 {
 697   return NO_REGS;
 698 }
 699
 700 #ifdef IRA_COVER_CLASSES
 701 const enum reg_class *
 702 default_ira_cover_classes (void)
 703 {
 704   static enum reg_class classes[] = IRA_COVER_CLASSES;
 705   return classes;
 706 }
 707 #endif
 708
 709 enum reg_class
 710 default_secondary_reload (bool in_p ATTRIBUTE_UNUSED, rtx x ATTRIBUTE_UNUSED,
 711                           enum reg_class reload_class ATTRIBUTE_UNUSED,
 712                           enum machine_mode reload_mode ATTRIBUTE_UNUSED,
 713                           secondary_reload_info *sri)
 714 {
 715   enum reg_class rclass = NO_REGS;
 716
 717   if (sri->prev_sri && sri->prev_sri->t_icode != CODE_FOR_nothing)
 718     {
 719       sri->icode = sri->prev_sri->t_icode;
 720       return NO_REGS;
 721     }
 722 #ifdef SECONDARY_INPUT_RELOAD_CLASS
 723   if (in_p)
 724     rclass = SECONDARY_INPUT_RELOAD_CLASS (reload_class, reload_mode, x);
 725 #endif
 726 #ifdef SECONDARY_OUTPUT_RELOAD_CLASS
 727   if (! in_p)
 728     rclass = SECONDARY_OUTPUT_RELOAD_CLASS (reload_class, reload_mode, x);
 729 #endif
 730   if (rclass != NO_REGS)
 731     {
 732       enum insn_code icode = (in_p ? reload_in_optab[(int) reload_mode]
 733                               : reload_out_optab[(int) reload_mode]);
 734
 735       if (icode != CODE_FOR_nothing
 736           && insn_data[(int) icode].operand[in_p].predicate
 737           && ! insn_data[(int) icode].operand[in_p].predicate (x, reload_mode))
 738         icode = CODE_FOR_nothing;
 739       else if (icode != CODE_FOR_nothing)
 740         {
 741           const char *insn_constraint, *scratch_constraint;
 742           char insn_letter, scratch_letter;
 743           enum reg_class insn_class, scratch_class;
 744
 745           gcc_assert (insn_data[(int) icode].n_operands == 3);
 746           insn_constraint = insn_data[(int) icode].operand[!in_p].constraint;
 747           if (!*insn_constraint)
 748             insn_class = ALL_REGS;
 749           else
 750             {
 751               if (in_p)
 752                 {
 753                   gcc_assert (*insn_constraint == '=');
 754                   insn_constraint++;
 755                 }
 756               insn_letter = *insn_constraint;
 757               insn_class
 758                 = (insn_letter == 'r' ? GENERAL_REGS
 759                    : REG_CLASS_FROM_CONSTRAINT ((unsigned char) insn_letter,
 760                                                 insn_constraint));
 761               gcc_assert (insn_class != NO_REGS);
 762             }
 763
 764           scratch_constraint = insn_data[(int) icode].operand[2].constraint;
 765           /* The scratch register's constraint must start with "=&",
 766              except for an input reload, where only "=" is necessary,
 767              and where it might be beneficial to re-use registers from
 768              the input.  */
 769           gcc_assert (scratch_constraint[0] == '='
 770                       && (in_p || scratch_constraint[1] == '&'));
 771           scratch_constraint++;
 772           if (*scratch_constraint == '&')
 773             scratch_constraint++;
 774           scratch_letter = *scratch_constraint;
 775           scratch_class
 776             = (scratch_letter == 'r' ? GENERAL_REGS
 777                : REG_CLASS_FROM_CONSTRAINT ((unsigned char) scratch_letter,
 778                                             scratch_constraint));
 779
 780           if (reg_class_subset_p (reload_class, insn_class))
 781             {
 782               gcc_assert (scratch_class == rclass);
 783               rclass = NO_REGS;
 784             }
 785           else
 786             rclass = insn_class;
 787
 788         }
 789       if (rclass == NO_REGS)
 790         sri->icode = icode;
 791       else
 792         sri->t_icode = icode;
 793     }
 794   return rclass;
 795 }
 796
 797 bool
 798 default_handle_c_option (size_t code ATTRIBUTE_UNUSED,
 799                          const char *arg ATTRIBUTE_UNUSED,
 800                          int value ATTRIBUTE_UNUSED)
 801 {
 802   return false;
 803 }
 804
 805 /* By default, if flag_pic is true, then neither local nor global relocs
 806    should be placed in readonly memory.  */
 807
 808 int
 809 default_reloc_rw_mask (void)
 810 {
 811   return flag_pic ? 3 : 0;
 812 }
 813
 814 /* By default, do no modification. */
 815 tree default_mangle_decl_assembler_name (tree decl ATTRIBUTE_UNUSED,
 816                                          tree id)
 817 {
 818    return id;
 819 }
 820
 821 bool
 822 default_builtin_vector_alignment_reachable (const_tree type, bool is_packed)
 823 {
 824   if (is_packed)
 825     return false;
 826
 827   /* Assuming that types whose size is > pointer-size are not guaranteed to be
 828      naturally aligned.  */
 829   if (tree_int_cst_compare (TYPE_SIZE (type), bitsize_int (POINTER_SIZE)) > 0)
 830     return false;
 831
 832   /* Assuming that types whose size is <= pointer-size
 833      are naturally aligned.  */
 834   return true;
 835 }
 836
 837 /* By default, assume that a target supports any factor of misalignment
 838    memory access if it supports movmisalign patten.
 839    is_packed is true if the memory access is defined in a packed struct.  */
 840 bool
 841 default_builtin_support_vector_misalignment (enum machine_mode mode,
 842                                              const_tree type
 843                                              ATTRIBUTE_UNUSED,
 844                                              int misalignment
 845                                              ATTRIBUTE_UNUSED,
 846                                              bool is_packed
 847                                              ATTRIBUTE_UNUSED)
 848 {
 849   if (optab_handler (movmisalign_optab, mode)->insn_code != CODE_FOR_nothing)
 850     return true;
 851   return false;
 852 }
 853
 854 /* Determine whether or not a pointer mode is valid. Assume defaults
 855    of ptr_mode or Pmode - can be overridden.  */
 856 bool
 857 default_valid_pointer_mode (enum machine_mode mode)
 858 {
 859   return (mode == ptr_mode || mode == Pmode);
 860 }
 861
 862 /* Return the mode for a pointer to a given ADDRSPACE, defaulting to ptr_mode
 863    for the generic address space only.  */
 864
 865 enum machine_mode
 866 default_addr_space_pointer_mode (addr_space_t addrspace ATTRIBUTE_UNUSED)
 867 {
 868   gcc_assert (ADDR_SPACE_GENERIC_P (addrspace));
 869   return ptr_mode;
 870 }
 871
 872 /* Return the mode for an address in a given ADDRSPACE, defaulting to Pmode
 873    for the generic address space only.  */
 874
 875 enum machine_mode
 876 default_addr_space_address_mode (addr_space_t addrspace ATTRIBUTE_UNUSED)
 877 {
 878   gcc_assert (ADDR_SPACE_GENERIC_P (addrspace));
 879   return Pmode;
 880 }
 881
 882 /* Named address space version of valid_pointer_mode.  */
 883
 884 bool
 885 default_addr_space_valid_pointer_mode (enum machine_mode mode, addr_space_t as)
 886 {
 887   if (!ADDR_SPACE_GENERIC_P (as))
 888     return (mode == targetm.addr_space.pointer_mode (as)
 889             || mode == targetm.addr_space.address_mode (as));
 890
 891   return targetm.valid_pointer_mode (mode);
 892 }
 893
 894 /* Some places still assume that all pointer or address modes are the
 895    standard Pmode and ptr_mode.  These optimizations become invalid if
 896    the target actually supports multiple different modes.  For now,
 897    we disable such optimizations on such targets, using this function.  */
 898
 899 bool
 900 target_default_pointer_address_modes_p (void)
 901 {
 902   if (targetm.addr_space.address_mode != default_addr_space_address_mode)
 903     return false;
 904   if (targetm.addr_space.pointer_mode != default_addr_space_pointer_mode)
 905     return false;
 906
 907   return true;
 908 }
 909
 910 /* Named address space version of legitimate_address_p.  */
 911
 912 bool
 913 default_addr_space_legitimate_address_p (enum machine_mode mode, rtx mem,
 914                                          bool strict, addr_space_t as)
 915 {
 916   if (!ADDR_SPACE_GENERIC_P (as))
 917     gcc_unreachable ();
 918
 919   return targetm.legitimate_address_p (mode, mem, strict);
 920 }
 921
 922 /* Named address space version of LEGITIMIZE_ADDRESS.  */
 923
 924 rtx
 925 default_addr_space_legitimize_address (rtx x, rtx oldx,
 926                                        enum machine_mode mode, addr_space_t as)
 927 {
 928   if (!ADDR_SPACE_GENERIC_P (as))
 929     return x;
 930
 931   return targetm.legitimize_address (x, oldx, mode);
 932 }
 933
 934 /* The default hook for determining if one named address space is a subset of
 935    another and to return which address space to use as the common address
 936    space.  */
 937
 938 bool
 939 default_addr_space_subset_p (addr_space_t subset, addr_space_t superset)
 940 {
 941   return (subset == superset);
 942 }
 943
 944 /* The default hook for TARGET_ADDR_SPACE_CONVERT. This hook should never be
 945    called for targets with only a generic address space.  */
 946
 947 rtx
 948 default_addr_space_convert (rtx op ATTRIBUTE_UNUSED,
 949                             tree from_type ATTRIBUTE_UNUSED,
 950                             tree to_type ATTRIBUTE_UNUSED)
 951 {
 952   gcc_unreachable ();
 953 }
 954
 955 bool
 956 default_hard_regno_scratch_ok (unsigned int regno ATTRIBUTE_UNUSED)
 957 {
 958   return true;
 959 }
 960
 961 /* The default implementation of TARGET_MODE_DEPENDENT_ADDRESS_P.  */
 962
 963 bool
 964 default_mode_dependent_address_p (const_rtx addr ATTRIBUTE_UNUSED)
 965 {
 966 #ifdef GO_IF_MODE_DEPENDENT_ADDRESS
 967
 968   GO_IF_MODE_DEPENDENT_ADDRESS (CONST_CAST_RTX (addr), win);
 969   return false;
 970   /* Label `win' might (not) be used via GO_IF_MODE_DEPENDENT_ADDRESS.  */
 971  win: ATTRIBUTE_UNUSED_LABEL
 972   return true;
 973
 974 #else
 975
 976   return false;
 977
 978 #endif
 979 }
 980
 981 bool
 982 default_target_option_valid_attribute_p (tree ARG_UNUSED (fndecl),
 983                                          tree ARG_UNUSED (name),
 984                                          tree ARG_UNUSED (args),
 985                                          int ARG_UNUSED (flags))
 986 {
 987   warning (OPT_Wattributes,
 988            "target attribute is not supported on this machine");
 989
 990   return false;
 991 }
 992
 993 bool
 994 default_target_option_pragma_parse (tree ARG_UNUSED (args),
 995                                     tree ARG_UNUSED (pop_target))
 996 {
 997   warning (OPT_Wpragmas,
 998            "#pragma GCC target is not supported for this machine");
 999
1000   return false;
1001 }
1002
1003 bool
1004 default_target_can_inline_p (tree caller, tree callee)
1005 {
1006   bool ret = false;
1007   tree callee_opts = DECL_FUNCTION_SPECIFIC_TARGET (callee);
1008   tree caller_opts = DECL_FUNCTION_SPECIFIC_TARGET (caller);
1009
1010   /* If callee has no option attributes, then it is ok to inline */
1011   if (!callee_opts)
1012     ret = true;
1013
1014   /* If caller has no option attributes, but callee does then it is not ok to
1015      inline */
1016   else if (!caller_opts)
1017     ret = false;
1018
1019   /* If both caller and callee have attributes, assume that if the pointer is
1020      different, the the two functions have different target options since
1021      build_target_option_node uses a hash table for the options.  */
1022   else
1023     ret = (callee_opts == caller_opts);
1024
1025   return ret;
1026 }
1027
1028 #ifndef HAVE_casesi
1029 # define HAVE_casesi 0
1030 #endif
1031
1032 /* If the machine does not have a case insn that compares the bounds,
1033    this means extra overhead for dispatch tables, which raises the
1034    threshold for using them.  */
1035
1036 unsigned int default_case_values_threshold (void)
1037 {
1038   return (HAVE_casesi ? 4 : 5);
1039 }
1040
1041 bool
1042 default_have_conditional_execution (void)
1043 {
1044 #ifdef HAVE_conditional_execution
1045   return HAVE_conditional_execution;
1046 #else
1047   return false;
1048 #endif
1049 }
1050
1051 #include "gt-targhooks.h"