Daily bump.
[official-gcc.git] / gcc / targhooks.c
blob6f071f80231c71dbcb44e39ce338533fd2f19cf6
1 /* Default target hook functions.
2 Copyright (C) 2003-2021 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify it under
7 the terms of the GNU General Public License as published by the Free
8 Software Foundation; either version 3, or (at your option) any later
9 version.
11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 for more details.
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
20 /* The migration of target macros to target hooks works as follows:
22 1. Create a target hook that uses the existing target macros to
23 implement the same functionality.
25 2. Convert all the MI files to use the hook instead of the macro.
27 3. Repeat for a majority of the remaining target macros. This will
28 take some time.
30 4. Tell target maintainers to start migrating.
32 5. Eventually convert the backends to override the hook instead of
33 defining the macros. This will take some time too.
35 6. TBD when, poison the macros. Unmigrated targets will break at
36 this point.
38 Note that we expect steps 1-3 to be done by the people that
39 understand what the MI does with each macro, and step 5 to be done
40 by the target maintainers for their respective targets.
42 Note that steps 1 and 2 don't have to be done together, but no
43 target can override the new hook until step 2 is complete for it.
45 Once the macros are poisoned, we will revert to the old migration
46 rules - migrate the macro, callers, and targets all at once. This
47 comment can thus be removed at that point. */
49 #include "config.h"
50 #include "system.h"
51 #include "coretypes.h"
52 #include "target.h"
53 #include "function.h"
54 #include "rtl.h"
55 #include "tree.h"
56 #include "tree-ssa-alias.h"
57 #include "gimple-expr.h"
58 #include "memmodel.h"
59 #include "backend.h"
60 #include "emit-rtl.h"
61 #include "df.h"
62 #include "tm_p.h"
63 #include "stringpool.h"
64 #include "tree-vrp.h"
65 #include "tree-ssanames.h"
66 #include "profile-count.h"
67 #include "optabs.h"
68 #include "regs.h"
69 #include "recog.h"
70 #include "diagnostic-core.h"
71 #include "fold-const.h"
72 #include "stor-layout.h"
73 #include "varasm.h"
74 #include "flags.h"
75 #include "explow.h"
76 #include "expmed.h"
77 #include "calls.h"
78 #include "expr.h"
79 #include "output.h"
80 #include "common/common-target.h"
81 #include "reload.h"
82 #include "intl.h"
83 #include "opts.h"
84 #include "gimplify.h"
85 #include "predict.h"
86 #include "real.h"
87 #include "langhooks.h"
88 #include "sbitmap.h"
89 #include "function-abi.h"
90 #include "attribs.h"
91 #include "asan.h"
92 #include "emit-rtl.h"
93 #include "gimple.h"
94 #include "cfgloop.h"
95 #include "tree-vectorizer.h"
97 bool
98 default_legitimate_address_p (machine_mode mode ATTRIBUTE_UNUSED,
99 rtx addr ATTRIBUTE_UNUSED,
100 bool strict ATTRIBUTE_UNUSED)
102 #ifdef GO_IF_LEGITIMATE_ADDRESS
103 /* Defer to the old implementation using a goto. */
104 if (strict)
105 return strict_memory_address_p (mode, addr);
106 else
107 return memory_address_p (mode, addr);
108 #else
109 gcc_unreachable ();
110 #endif
113 void
114 default_external_libcall (rtx fun ATTRIBUTE_UNUSED)
116 #ifdef ASM_OUTPUT_EXTERNAL_LIBCALL
117 ASM_OUTPUT_EXTERNAL_LIBCALL (asm_out_file, fun);
118 #endif
122 default_unspec_may_trap_p (const_rtx x, unsigned flags)
124 int i;
126 /* Any floating arithmetic may trap. */
127 if ((SCALAR_FLOAT_MODE_P (GET_MODE (x)) && flag_trapping_math))
128 return 1;
130 for (i = 0; i < XVECLEN (x, 0); ++i)
132 if (may_trap_p_1 (XVECEXP (x, 0, i), flags))
133 return 1;
136 return 0;
139 machine_mode
140 default_promote_function_mode (const_tree type ATTRIBUTE_UNUSED,
141 machine_mode mode,
142 int *punsignedp ATTRIBUTE_UNUSED,
143 const_tree funtype ATTRIBUTE_UNUSED,
144 int for_return ATTRIBUTE_UNUSED)
146 if (type != NULL_TREE && for_return == 2)
147 return promote_mode (type, mode, punsignedp);
148 return mode;
151 machine_mode
152 default_promote_function_mode_always_promote (const_tree type,
153 machine_mode mode,
154 int *punsignedp,
155 const_tree funtype ATTRIBUTE_UNUSED,
156 int for_return ATTRIBUTE_UNUSED)
158 return promote_mode (type, mode, punsignedp);
161 machine_mode
162 default_cc_modes_compatible (machine_mode m1, machine_mode m2)
164 if (m1 == m2)
165 return m1;
166 return VOIDmode;
169 bool
170 default_return_in_memory (const_tree type,
171 const_tree fntype ATTRIBUTE_UNUSED)
173 return (TYPE_MODE (type) == BLKmode);
177 default_legitimize_address (rtx x, rtx orig_x ATTRIBUTE_UNUSED,
178 machine_mode mode ATTRIBUTE_UNUSED)
180 return x;
183 bool
184 default_legitimize_address_displacement (rtx *, rtx *, poly_int64,
185 machine_mode)
187 return false;
190 bool
191 default_const_not_ok_for_debug_p (rtx x)
193 if (GET_CODE (x) == UNSPEC)
194 return true;
195 return false;
199 default_expand_builtin_saveregs (void)
201 error ("%<__builtin_saveregs%> not supported by this target");
202 return const0_rtx;
205 void
206 default_setup_incoming_varargs (cumulative_args_t,
207 const function_arg_info &, int *, int)
211 /* The default implementation of TARGET_BUILTIN_SETJMP_FRAME_VALUE. */
214 default_builtin_setjmp_frame_value (void)
216 return virtual_stack_vars_rtx;
219 /* Generic hook that takes a CUMULATIVE_ARGS pointer and returns false. */
221 bool
222 hook_bool_CUMULATIVE_ARGS_false (cumulative_args_t ca ATTRIBUTE_UNUSED)
224 return false;
227 bool
228 default_pretend_outgoing_varargs_named (cumulative_args_t ca ATTRIBUTE_UNUSED)
230 return (targetm.calls.setup_incoming_varargs
231 != default_setup_incoming_varargs);
234 scalar_int_mode
235 default_eh_return_filter_mode (void)
237 return targetm.unwind_word_mode ();
240 scalar_int_mode
241 default_libgcc_cmp_return_mode (void)
243 return word_mode;
246 scalar_int_mode
247 default_libgcc_shift_count_mode (void)
249 return word_mode;
252 scalar_int_mode
253 default_unwind_word_mode (void)
255 return word_mode;
258 /* The default implementation of TARGET_SHIFT_TRUNCATION_MASK. */
260 unsigned HOST_WIDE_INT
261 default_shift_truncation_mask (machine_mode mode)
263 return SHIFT_COUNT_TRUNCATED ? GET_MODE_UNIT_BITSIZE (mode) - 1 : 0;
266 /* The default implementation of TARGET_MIN_DIVISIONS_FOR_RECIP_MUL. */
268 unsigned int
269 default_min_divisions_for_recip_mul (machine_mode mode ATTRIBUTE_UNUSED)
271 return have_insn_for (DIV, mode) ? 3 : 2;
274 /* The default implementation of TARGET_MODE_REP_EXTENDED. */
277 default_mode_rep_extended (scalar_int_mode, scalar_int_mode)
279 return UNKNOWN;
282 /* Generic hook that takes a CUMULATIVE_ARGS pointer and returns true. */
284 bool
285 hook_bool_CUMULATIVE_ARGS_true (cumulative_args_t a ATTRIBUTE_UNUSED)
287 return true;
290 /* Return machine mode for non-standard suffix
291 or VOIDmode if non-standard suffixes are unsupported. */
292 machine_mode
293 default_mode_for_suffix (char suffix ATTRIBUTE_UNUSED)
295 return VOIDmode;
298 /* The generic C++ ABI specifies this is a 64-bit value. */
299 tree
300 default_cxx_guard_type (void)
302 return long_long_integer_type_node;
305 /* Returns the size of the cookie to use when allocating an array
306 whose elements have the indicated TYPE. Assumes that it is already
307 known that a cookie is needed. */
309 tree
310 default_cxx_get_cookie_size (tree type)
312 tree cookie_size;
314 /* We need to allocate an additional max (sizeof (size_t), alignof
315 (true_type)) bytes. */
316 tree sizetype_size;
317 tree type_align;
319 sizetype_size = size_in_bytes (sizetype);
320 type_align = size_int (TYPE_ALIGN_UNIT (type));
321 if (tree_int_cst_lt (type_align, sizetype_size))
322 cookie_size = sizetype_size;
323 else
324 cookie_size = type_align;
326 return cookie_size;
329 /* Return true if a parameter must be passed by reference. This version
330 of the TARGET_PASS_BY_REFERENCE hook uses just MUST_PASS_IN_STACK. */
332 bool
333 hook_pass_by_reference_must_pass_in_stack (cumulative_args_t,
334 const function_arg_info &arg)
336 return targetm.calls.must_pass_in_stack (arg);
339 /* Return true if a parameter follows callee copies conventions. This
340 version of the hook is true for all named arguments. */
342 bool
343 hook_callee_copies_named (cumulative_args_t, const function_arg_info &arg)
345 return arg.named;
348 /* Emit to STREAM the assembler syntax for insn operand X. */
350 void
351 default_print_operand (FILE *stream ATTRIBUTE_UNUSED, rtx x ATTRIBUTE_UNUSED,
352 int code ATTRIBUTE_UNUSED)
354 #ifdef PRINT_OPERAND
355 PRINT_OPERAND (stream, x, code);
356 #else
357 gcc_unreachable ();
358 #endif
361 /* Emit to STREAM the assembler syntax for an insn operand whose memory
362 address is X. */
364 void
365 default_print_operand_address (FILE *stream ATTRIBUTE_UNUSED,
366 machine_mode /*mode*/,
367 rtx x ATTRIBUTE_UNUSED)
369 #ifdef PRINT_OPERAND_ADDRESS
370 PRINT_OPERAND_ADDRESS (stream, x);
371 #else
372 gcc_unreachable ();
373 #endif
376 /* Return true if CODE is a valid punctuation character for the
377 `print_operand' hook. */
379 bool
380 default_print_operand_punct_valid_p (unsigned char code ATTRIBUTE_UNUSED)
382 #ifdef PRINT_OPERAND_PUNCT_VALID_P
383 return PRINT_OPERAND_PUNCT_VALID_P (code);
384 #else
385 return false;
386 #endif
389 /* The default implementation of TARGET_MANGLE_ASSEMBLER_NAME. */
390 tree
391 default_mangle_assembler_name (const char *name ATTRIBUTE_UNUSED)
393 const char *skipped = name + (*name == '*' ? 1 : 0);
394 const char *stripped = targetm.strip_name_encoding (skipped);
395 if (*name != '*' && user_label_prefix[0])
396 stripped = ACONCAT ((user_label_prefix, stripped, NULL));
397 return get_identifier (stripped);
400 /* The default implementation of TARGET_TRANSLATE_MODE_ATTRIBUTE. */
402 machine_mode
403 default_translate_mode_attribute (machine_mode mode)
405 return mode;
408 /* True if MODE is valid for the target. By "valid", we mean able to
409 be manipulated in non-trivial ways. In particular, this means all
410 the arithmetic is supported.
412 By default we guess this means that any C type is supported. If
413 we can't map the mode back to a type that would be available in C,
414 then reject it. Special case, here, is the double-word arithmetic
415 supported by optabs.c. */
417 bool
418 default_scalar_mode_supported_p (scalar_mode mode)
420 int precision = GET_MODE_PRECISION (mode);
422 switch (GET_MODE_CLASS (mode))
424 case MODE_PARTIAL_INT:
425 case MODE_INT:
426 if (precision == CHAR_TYPE_SIZE)
427 return true;
428 if (precision == SHORT_TYPE_SIZE)
429 return true;
430 if (precision == INT_TYPE_SIZE)
431 return true;
432 if (precision == LONG_TYPE_SIZE)
433 return true;
434 if (precision == LONG_LONG_TYPE_SIZE)
435 return true;
436 if (precision == 2 * BITS_PER_WORD)
437 return true;
438 return false;
440 case MODE_FLOAT:
441 if (precision == FLOAT_TYPE_SIZE)
442 return true;
443 if (precision == DOUBLE_TYPE_SIZE)
444 return true;
445 if (precision == LONG_DOUBLE_TYPE_SIZE)
446 return true;
447 return false;
449 case MODE_DECIMAL_FLOAT:
450 case MODE_FRACT:
451 case MODE_UFRACT:
452 case MODE_ACCUM:
453 case MODE_UACCUM:
454 return false;
456 default:
457 gcc_unreachable ();
461 /* Return true if libgcc supports floating-point mode MODE (known to
462 be supported as a scalar mode). */
464 bool
465 default_libgcc_floating_mode_supported_p (scalar_float_mode mode)
467 switch (mode)
469 #ifdef HAVE_SFmode
470 case E_SFmode:
471 #endif
472 #ifdef HAVE_DFmode
473 case E_DFmode:
474 #endif
475 #ifdef HAVE_XFmode
476 case E_XFmode:
477 #endif
478 #ifdef HAVE_TFmode
479 case E_TFmode:
480 #endif
481 return true;
483 default:
484 return false;
488 /* Return the machine mode to use for the type _FloatN, if EXTENDED is
489 false, or _FloatNx, if EXTENDED is true, or VOIDmode if not
490 supported. */
491 opt_scalar_float_mode
492 default_floatn_mode (int n, bool extended)
494 if (extended)
496 opt_scalar_float_mode cand1, cand2;
497 scalar_float_mode mode;
498 switch (n)
500 case 32:
501 #ifdef HAVE_DFmode
502 cand1 = DFmode;
503 #endif
504 break;
506 case 64:
507 #ifdef HAVE_XFmode
508 cand1 = XFmode;
509 #endif
510 #ifdef HAVE_TFmode
511 cand2 = TFmode;
512 #endif
513 break;
515 case 128:
516 break;
518 default:
519 /* Those are the only valid _FloatNx types. */
520 gcc_unreachable ();
522 if (cand1.exists (&mode)
523 && REAL_MODE_FORMAT (mode)->ieee_bits > n
524 && targetm.scalar_mode_supported_p (mode)
525 && targetm.libgcc_floating_mode_supported_p (mode))
526 return cand1;
527 if (cand2.exists (&mode)
528 && REAL_MODE_FORMAT (mode)->ieee_bits > n
529 && targetm.scalar_mode_supported_p (mode)
530 && targetm.libgcc_floating_mode_supported_p (mode))
531 return cand2;
533 else
535 opt_scalar_float_mode cand;
536 scalar_float_mode mode;
537 switch (n)
539 case 16:
540 /* Always enable _Float16 if we have basic support for the mode.
541 Targets can control the range and precision of operations on
542 the _Float16 type using TARGET_C_EXCESS_PRECISION. */
543 #ifdef HAVE_HFmode
544 cand = HFmode;
545 #endif
546 break;
548 case 32:
549 #ifdef HAVE_SFmode
550 cand = SFmode;
551 #endif
552 break;
554 case 64:
555 #ifdef HAVE_DFmode
556 cand = DFmode;
557 #endif
558 break;
560 case 128:
561 #ifdef HAVE_TFmode
562 cand = TFmode;
563 #endif
564 break;
566 default:
567 break;
569 if (cand.exists (&mode)
570 && REAL_MODE_FORMAT (mode)->ieee_bits == n
571 && targetm.scalar_mode_supported_p (mode)
572 && targetm.libgcc_floating_mode_supported_p (mode))
573 return cand;
575 return opt_scalar_float_mode ();
578 /* Define this to return true if the _Floatn and _Floatnx built-in functions
579 should implicitly enable the built-in function without the __builtin_ prefix
580 in addition to the normal built-in function with the __builtin_ prefix. The
581 default is to only enable built-in functions without the __builtin_ prefix
582 for the GNU C langauge. The argument FUNC is the enum builtin_in_function
583 id of the function to be enabled. */
585 bool
586 default_floatn_builtin_p (int func ATTRIBUTE_UNUSED)
588 static bool first_time_p = true;
589 static bool c_or_objective_c;
591 if (first_time_p)
593 first_time_p = false;
594 c_or_objective_c = lang_GNU_C () || lang_GNU_OBJC ();
597 return c_or_objective_c;
600 /* Make some target macros useable by target-independent code. */
601 bool
602 targhook_words_big_endian (void)
604 return !!WORDS_BIG_ENDIAN;
607 bool
608 targhook_float_words_big_endian (void)
610 return !!FLOAT_WORDS_BIG_ENDIAN;
613 /* True if the target supports floating-point exceptions and rounding
614 modes. */
616 bool
617 default_float_exceptions_rounding_supported_p (void)
619 #ifdef HAVE_adddf3
620 return HAVE_adddf3;
621 #else
622 return false;
623 #endif
626 /* True if the target supports decimal floating point. */
628 bool
629 default_decimal_float_supported_p (void)
631 return ENABLE_DECIMAL_FLOAT;
634 /* True if the target supports fixed-point arithmetic. */
636 bool
637 default_fixed_point_supported_p (void)
639 return ENABLE_FIXED_POINT;
642 /* True if the target supports GNU indirect functions. */
644 bool
645 default_has_ifunc_p (void)
647 return HAVE_GNU_INDIRECT_FUNCTION;
650 /* Return true if we predict the loop LOOP will be transformed to a
651 low-overhead loop, otherwise return false.
653 By default, false is returned, as this hook's applicability should be
654 verified for each target. Target maintainers should re-define the hook
655 if the target can take advantage of it. */
657 bool
658 default_predict_doloop_p (class loop *loop ATTRIBUTE_UNUSED)
660 return false;
663 /* By default, just use the input MODE itself. */
665 machine_mode
666 default_preferred_doloop_mode (machine_mode mode)
668 return mode;
671 /* NULL if INSN insn is valid within a low-overhead loop, otherwise returns
672 an error message.
674 This function checks whether a given INSN is valid within a low-overhead
675 loop. If INSN is invalid it returns the reason for that, otherwise it
676 returns NULL. A called function may clobber any special registers required
677 for low-overhead looping. Additionally, some targets (eg, PPC) use the count
678 register for branch on table instructions. We reject the doloop pattern in
679 these cases. */
681 const char *
682 default_invalid_within_doloop (const rtx_insn *insn)
684 if (CALL_P (insn))
685 return "Function call in loop.";
687 if (tablejump_p (insn, NULL, NULL) || computed_jump_p (insn))
688 return "Computed branch in the loop.";
690 return NULL;
693 /* Mapping of builtin functions to vectorized variants. */
695 tree
696 default_builtin_vectorized_function (unsigned int, tree, tree)
698 return NULL_TREE;
701 /* Mapping of target builtin functions to vectorized variants. */
703 tree
704 default_builtin_md_vectorized_function (tree, tree, tree)
706 return NULL_TREE;
709 /* Default vectorizer cost model values. */
712 default_builtin_vectorization_cost (enum vect_cost_for_stmt type_of_cost,
713 tree vectype,
714 int misalign ATTRIBUTE_UNUSED)
716 switch (type_of_cost)
718 case scalar_stmt:
719 case scalar_load:
720 case scalar_store:
721 case vector_stmt:
722 case vector_load:
723 case vector_store:
724 case vec_to_scalar:
725 case scalar_to_vec:
726 case cond_branch_not_taken:
727 case vec_perm:
728 case vec_promote_demote:
729 return 1;
731 case unaligned_load:
732 case unaligned_store:
733 return 2;
735 case cond_branch_taken:
736 return 3;
738 case vec_construct:
739 return estimated_poly_value (TYPE_VECTOR_SUBPARTS (vectype)) - 1;
741 default:
742 gcc_unreachable ();
746 /* Reciprocal. */
748 tree
749 default_builtin_reciprocal (tree)
751 return NULL_TREE;
754 bool
755 hook_bool_CUMULATIVE_ARGS_arg_info_false (cumulative_args_t,
756 const function_arg_info &)
758 return false;
761 bool
762 hook_bool_CUMULATIVE_ARGS_arg_info_true (cumulative_args_t,
763 const function_arg_info &)
765 return true;
769 hook_int_CUMULATIVE_ARGS_arg_info_0 (cumulative_args_t,
770 const function_arg_info &)
772 return 0;
775 void
776 hook_void_CUMULATIVE_ARGS_tree (cumulative_args_t ca ATTRIBUTE_UNUSED,
777 tree ATTRIBUTE_UNUSED)
781 /* Default implementation of TARGET_PUSH_ARGUMENT. */
783 bool
784 default_push_argument (unsigned int)
786 #ifdef PUSH_ROUNDING
787 return !ACCUMULATE_OUTGOING_ARGS;
788 #else
789 return false;
790 #endif
793 void
794 default_function_arg_advance (cumulative_args_t, const function_arg_info &)
796 gcc_unreachable ();
799 /* Default implementation of TARGET_FUNCTION_ARG_OFFSET. */
801 HOST_WIDE_INT
802 default_function_arg_offset (machine_mode, const_tree)
804 return 0;
807 /* Default implementation of TARGET_FUNCTION_ARG_PADDING: usually pad
808 upward, but pad short args downward on big-endian machines. */
810 pad_direction
811 default_function_arg_padding (machine_mode mode, const_tree type)
813 if (!BYTES_BIG_ENDIAN)
814 return PAD_UPWARD;
816 unsigned HOST_WIDE_INT size;
817 if (mode == BLKmode)
819 if (!type || TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
820 return PAD_UPWARD;
821 size = int_size_in_bytes (type);
823 else
824 /* Targets with variable-sized modes must override this hook
825 and handle variable-sized modes explicitly. */
826 size = GET_MODE_SIZE (mode).to_constant ();
828 if (size < (PARM_BOUNDARY / BITS_PER_UNIT))
829 return PAD_DOWNWARD;
831 return PAD_UPWARD;
835 default_function_arg (cumulative_args_t, const function_arg_info &)
837 gcc_unreachable ();
841 default_function_incoming_arg (cumulative_args_t, const function_arg_info &)
843 gcc_unreachable ();
846 unsigned int
847 default_function_arg_boundary (machine_mode mode ATTRIBUTE_UNUSED,
848 const_tree type ATTRIBUTE_UNUSED)
850 return PARM_BOUNDARY;
853 unsigned int
854 default_function_arg_round_boundary (machine_mode mode ATTRIBUTE_UNUSED,
855 const_tree type ATTRIBUTE_UNUSED)
857 return PARM_BOUNDARY;
860 void
861 hook_void_bitmap (bitmap regs ATTRIBUTE_UNUSED)
865 const char *
866 hook_invalid_arg_for_unprototyped_fn (
867 const_tree typelist ATTRIBUTE_UNUSED,
868 const_tree funcdecl ATTRIBUTE_UNUSED,
869 const_tree val ATTRIBUTE_UNUSED)
871 return NULL;
874 /* Initialize the stack protection decls. */
876 /* Stack protection related decls living in libgcc. */
877 static GTY(()) tree stack_chk_guard_decl;
879 tree
880 default_stack_protect_guard (void)
882 tree t = stack_chk_guard_decl;
884 if (t == NULL)
886 rtx x;
888 t = build_decl (UNKNOWN_LOCATION,
889 VAR_DECL, get_identifier ("__stack_chk_guard"),
890 ptr_type_node);
891 TREE_STATIC (t) = 1;
892 TREE_PUBLIC (t) = 1;
893 DECL_EXTERNAL (t) = 1;
894 TREE_USED (t) = 1;
895 TREE_THIS_VOLATILE (t) = 1;
896 DECL_ARTIFICIAL (t) = 1;
897 DECL_IGNORED_P (t) = 1;
899 /* Do not share RTL as the declaration is visible outside of
900 current function. */
901 x = DECL_RTL (t);
902 RTX_FLAG (x, used) = 1;
904 stack_chk_guard_decl = t;
907 return t;
910 static GTY(()) tree stack_chk_fail_decl;
912 tree
913 default_external_stack_protect_fail (void)
915 tree t = stack_chk_fail_decl;
917 if (t == NULL_TREE)
919 t = build_function_type_list (void_type_node, NULL_TREE);
920 t = build_decl (UNKNOWN_LOCATION,
921 FUNCTION_DECL, get_identifier ("__stack_chk_fail"), t);
922 TREE_STATIC (t) = 1;
923 TREE_PUBLIC (t) = 1;
924 DECL_EXTERNAL (t) = 1;
925 TREE_USED (t) = 1;
926 TREE_THIS_VOLATILE (t) = 1;
927 TREE_NOTHROW (t) = 1;
928 DECL_ARTIFICIAL (t) = 1;
929 DECL_IGNORED_P (t) = 1;
930 DECL_VISIBILITY (t) = VISIBILITY_DEFAULT;
931 DECL_VISIBILITY_SPECIFIED (t) = 1;
933 stack_chk_fail_decl = t;
936 return build_call_expr (t, 0);
939 tree
940 default_hidden_stack_protect_fail (void)
942 #ifndef HAVE_GAS_HIDDEN
943 return default_external_stack_protect_fail ();
944 #else
945 tree t = stack_chk_fail_decl;
947 if (!flag_pic)
948 return default_external_stack_protect_fail ();
950 if (t == NULL_TREE)
952 t = build_function_type_list (void_type_node, NULL_TREE);
953 t = build_decl (UNKNOWN_LOCATION, FUNCTION_DECL,
954 get_identifier ("__stack_chk_fail_local"), t);
955 TREE_STATIC (t) = 1;
956 TREE_PUBLIC (t) = 1;
957 DECL_EXTERNAL (t) = 1;
958 TREE_USED (t) = 1;
959 TREE_THIS_VOLATILE (t) = 1;
960 TREE_NOTHROW (t) = 1;
961 DECL_ARTIFICIAL (t) = 1;
962 DECL_IGNORED_P (t) = 1;
963 DECL_VISIBILITY_SPECIFIED (t) = 1;
964 DECL_VISIBILITY (t) = VISIBILITY_HIDDEN;
966 stack_chk_fail_decl = t;
969 return build_call_expr (t, 0);
970 #endif
973 bool
974 hook_bool_const_rtx_commutative_p (const_rtx x,
975 int outer_code ATTRIBUTE_UNUSED)
977 return COMMUTATIVE_P (x);
981 default_function_value (const_tree ret_type ATTRIBUTE_UNUSED,
982 const_tree fn_decl_or_type,
983 bool outgoing ATTRIBUTE_UNUSED)
985 /* The old interface doesn't handle receiving the function type. */
986 if (fn_decl_or_type
987 && !DECL_P (fn_decl_or_type))
988 fn_decl_or_type = NULL;
990 #ifdef FUNCTION_VALUE
991 return FUNCTION_VALUE (ret_type, fn_decl_or_type);
992 #else
993 gcc_unreachable ();
994 #endif
998 default_libcall_value (machine_mode mode ATTRIBUTE_UNUSED,
999 const_rtx fun ATTRIBUTE_UNUSED)
1001 #ifdef LIBCALL_VALUE
1002 return LIBCALL_VALUE (MACRO_MODE (mode));
1003 #else
1004 gcc_unreachable ();
1005 #endif
1008 /* The default hook for TARGET_FUNCTION_VALUE_REGNO_P. */
1010 bool
1011 default_function_value_regno_p (const unsigned int regno ATTRIBUTE_UNUSED)
1013 #ifdef FUNCTION_VALUE_REGNO_P
1014 return FUNCTION_VALUE_REGNO_P (regno);
1015 #else
1016 gcc_unreachable ();
1017 #endif
1020 /* The default hook for TARGET_ZERO_CALL_USED_REGS. */
1022 HARD_REG_SET
1023 default_zero_call_used_regs (HARD_REG_SET need_zeroed_hardregs)
1025 gcc_assert (!hard_reg_set_empty_p (need_zeroed_hardregs));
1027 HARD_REG_SET failed;
1028 CLEAR_HARD_REG_SET (failed);
1029 bool progress = false;
1031 /* First, try to zero each register in need_zeroed_hardregs by
1032 loading a zero into it, taking note of any failures in
1033 FAILED. */
1034 for (unsigned int regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
1035 if (TEST_HARD_REG_BIT (need_zeroed_hardregs, regno))
1037 rtx_insn *last_insn = get_last_insn ();
1038 machine_mode mode = GET_MODE (regno_reg_rtx[regno]);
1039 rtx zero = CONST0_RTX (mode);
1040 rtx_insn *insn = emit_move_insn (regno_reg_rtx[regno], zero);
1041 if (!valid_insn_p (insn))
1043 SET_HARD_REG_BIT (failed, regno);
1044 delete_insns_since (last_insn);
1046 else
1047 progress = true;
1050 /* Now retry with copies from zeroed registers, as long as we've
1051 made some PROGRESS, and registers remain to be zeroed in
1052 FAILED. */
1053 while (progress && !hard_reg_set_empty_p (failed))
1055 HARD_REG_SET retrying = failed;
1057 CLEAR_HARD_REG_SET (failed);
1058 progress = false;
1060 for (unsigned int regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
1061 if (TEST_HARD_REG_BIT (retrying, regno))
1063 machine_mode mode = GET_MODE (regno_reg_rtx[regno]);
1064 bool success = false;
1065 /* Look for a source. */
1066 for (unsigned int src = 0; src < FIRST_PSEUDO_REGISTER; src++)
1068 /* If SRC hasn't been zeroed (yet?), skip it. */
1069 if (! TEST_HARD_REG_BIT (need_zeroed_hardregs, src))
1070 continue;
1071 if (TEST_HARD_REG_BIT (retrying, src))
1072 continue;
1074 /* Check that SRC can hold MODE, and that any other
1075 registers needed to hold MODE in SRC have also been
1076 zeroed. */
1077 if (!targetm.hard_regno_mode_ok (src, mode))
1078 continue;
1079 unsigned n = targetm.hard_regno_nregs (src, mode);
1080 bool ok = true;
1081 for (unsigned i = 1; ok && i < n; i++)
1082 ok = (TEST_HARD_REG_BIT (need_zeroed_hardregs, src + i)
1083 && !TEST_HARD_REG_BIT (retrying, src + i));
1084 if (!ok)
1085 continue;
1087 /* SRC is usable, try to copy from it. */
1088 rtx_insn *last_insn = get_last_insn ();
1089 rtx zsrc = gen_rtx_REG (mode, src);
1090 rtx_insn *insn = emit_move_insn (regno_reg_rtx[regno], zsrc);
1091 if (!valid_insn_p (insn))
1092 /* It didn't work, remove any inserts. We'll look
1093 for another SRC. */
1094 delete_insns_since (last_insn);
1095 else
1097 /* We're done for REGNO. */
1098 success = true;
1099 break;
1103 /* If nothing worked for REGNO this round, marked it to be
1104 retried if we get another round. */
1105 if (!success)
1106 SET_HARD_REG_BIT (failed, regno);
1107 else
1108 /* Take note so as to enable another round if needed. */
1109 progress = true;
1113 /* If any register remained, report it. */
1114 if (!progress)
1116 static bool issued_error;
1117 if (!issued_error)
1119 issued_error = true;
1120 sorry ("%qs not supported on this target",
1121 "-fzero-call-used-regs");
1125 return need_zeroed_hardregs;
1129 default_internal_arg_pointer (void)
1131 /* If the reg that the virtual arg pointer will be translated into is
1132 not a fixed reg or is the stack pointer, make a copy of the virtual
1133 arg pointer, and address parms via the copy. The frame pointer is
1134 considered fixed even though it is not marked as such. */
1135 if ((ARG_POINTER_REGNUM == STACK_POINTER_REGNUM
1136 || ! (fixed_regs[ARG_POINTER_REGNUM]
1137 || ARG_POINTER_REGNUM == FRAME_POINTER_REGNUM)))
1138 return copy_to_reg (virtual_incoming_args_rtx);
1139 else
1140 return virtual_incoming_args_rtx;
1144 default_static_chain (const_tree ARG_UNUSED (fndecl_or_type), bool incoming_p)
1146 if (incoming_p)
1148 #ifdef STATIC_CHAIN_INCOMING_REGNUM
1149 return gen_rtx_REG (Pmode, STATIC_CHAIN_INCOMING_REGNUM);
1150 #endif
1153 #ifdef STATIC_CHAIN_REGNUM
1154 return gen_rtx_REG (Pmode, STATIC_CHAIN_REGNUM);
1155 #endif
1158 static bool issued_error;
1159 if (!issued_error)
1161 issued_error = true;
1162 sorry ("nested functions not supported on this target");
1165 /* It really doesn't matter what we return here, so long at it
1166 doesn't cause the rest of the compiler to crash. */
1167 return gen_rtx_MEM (Pmode, stack_pointer_rtx);
1171 void
1172 default_trampoline_init (rtx ARG_UNUSED (m_tramp), tree ARG_UNUSED (t_func),
1173 rtx ARG_UNUSED (r_chain))
1175 sorry ("nested function trampolines not supported on this target");
1178 poly_int64
1179 default_return_pops_args (tree, tree, poly_int64)
1181 return 0;
1184 reg_class_t
1185 default_ira_change_pseudo_allocno_class (int regno ATTRIBUTE_UNUSED,
1186 reg_class_t cl,
1187 reg_class_t best_cl ATTRIBUTE_UNUSED)
1189 return cl;
1192 extern bool
1193 default_lra_p (void)
1195 return true;
1199 default_register_priority (int hard_regno ATTRIBUTE_UNUSED)
1201 return 0;
1204 extern bool
1205 default_register_usage_leveling_p (void)
1207 return false;
1210 extern bool
1211 default_different_addr_displacement_p (void)
1213 return false;
1216 reg_class_t
1217 default_secondary_reload (bool in_p ATTRIBUTE_UNUSED, rtx x ATTRIBUTE_UNUSED,
1218 reg_class_t reload_class_i ATTRIBUTE_UNUSED,
1219 machine_mode reload_mode ATTRIBUTE_UNUSED,
1220 secondary_reload_info *sri)
1222 enum reg_class rclass = NO_REGS;
1223 enum reg_class reload_class = (enum reg_class) reload_class_i;
1225 if (sri->prev_sri && sri->prev_sri->t_icode != CODE_FOR_nothing)
1227 sri->icode = sri->prev_sri->t_icode;
1228 return NO_REGS;
1230 #ifdef SECONDARY_INPUT_RELOAD_CLASS
1231 if (in_p)
1232 rclass = SECONDARY_INPUT_RELOAD_CLASS (reload_class,
1233 MACRO_MODE (reload_mode), x);
1234 #endif
1235 #ifdef SECONDARY_OUTPUT_RELOAD_CLASS
1236 if (! in_p)
1237 rclass = SECONDARY_OUTPUT_RELOAD_CLASS (reload_class,
1238 MACRO_MODE (reload_mode), x);
1239 #endif
1240 if (rclass != NO_REGS)
1242 enum insn_code icode
1243 = direct_optab_handler (in_p ? reload_in_optab : reload_out_optab,
1244 reload_mode);
1246 if (icode != CODE_FOR_nothing
1247 && !insn_operand_matches (icode, in_p, x))
1248 icode = CODE_FOR_nothing;
1249 else if (icode != CODE_FOR_nothing)
1251 const char *insn_constraint, *scratch_constraint;
1252 enum reg_class insn_class, scratch_class;
1254 gcc_assert (insn_data[(int) icode].n_operands == 3);
1255 insn_constraint = insn_data[(int) icode].operand[!in_p].constraint;
1256 if (!*insn_constraint)
1257 insn_class = ALL_REGS;
1258 else
1260 if (in_p)
1262 gcc_assert (*insn_constraint == '=');
1263 insn_constraint++;
1265 insn_class = (reg_class_for_constraint
1266 (lookup_constraint (insn_constraint)));
1267 gcc_assert (insn_class != NO_REGS);
1270 scratch_constraint = insn_data[(int) icode].operand[2].constraint;
1271 /* The scratch register's constraint must start with "=&",
1272 except for an input reload, where only "=" is necessary,
1273 and where it might be beneficial to re-use registers from
1274 the input. */
1275 gcc_assert (scratch_constraint[0] == '='
1276 && (in_p || scratch_constraint[1] == '&'));
1277 scratch_constraint++;
1278 if (*scratch_constraint == '&')
1279 scratch_constraint++;
1280 scratch_class = (reg_class_for_constraint
1281 (lookup_constraint (scratch_constraint)));
1283 if (reg_class_subset_p (reload_class, insn_class))
1285 gcc_assert (scratch_class == rclass);
1286 rclass = NO_REGS;
1288 else
1289 rclass = insn_class;
1292 if (rclass == NO_REGS)
1293 sri->icode = icode;
1294 else
1295 sri->t_icode = icode;
1297 return rclass;
1300 /* The default implementation of TARGET_SECONDARY_MEMORY_NEEDED_MODE. */
1302 machine_mode
1303 default_secondary_memory_needed_mode (machine_mode mode)
1305 if (!targetm.lra_p ()
1306 && known_lt (GET_MODE_BITSIZE (mode), BITS_PER_WORD)
1307 && INTEGRAL_MODE_P (mode))
1308 return mode_for_size (BITS_PER_WORD, GET_MODE_CLASS (mode), 0).require ();
1309 return mode;
1312 /* By default, if flag_pic is true, then neither local nor global relocs
1313 should be placed in readonly memory. */
1316 default_reloc_rw_mask (void)
1318 return flag_pic ? 3 : 0;
1321 /* By default, address diff vectors are generated
1322 for jump tables when flag_pic is true. */
1324 bool
1325 default_generate_pic_addr_diff_vec (void)
1327 return flag_pic;
1330 /* By default, do no modification. */
1331 tree default_mangle_decl_assembler_name (tree decl ATTRIBUTE_UNUSED,
1332 tree id)
1334 return id;
1337 /* The default implementation of TARGET_STATIC_RTX_ALIGNMENT. */
1339 HOST_WIDE_INT
1340 default_static_rtx_alignment (machine_mode mode)
1342 return GET_MODE_ALIGNMENT (mode);
1345 /* The default implementation of TARGET_CONSTANT_ALIGNMENT. */
1347 HOST_WIDE_INT
1348 default_constant_alignment (const_tree, HOST_WIDE_INT align)
1350 return align;
1353 /* An implementation of TARGET_CONSTANT_ALIGNMENT that aligns strings
1354 to at least BITS_PER_WORD but otherwise makes no changes. */
1356 HOST_WIDE_INT
1357 constant_alignment_word_strings (const_tree exp, HOST_WIDE_INT align)
1359 if (TREE_CODE (exp) == STRING_CST)
1360 return MAX (align, BITS_PER_WORD);
1361 return align;
1364 /* Default to natural alignment for vector types, bounded by
1365 MAX_OFILE_ALIGNMENT. */
1367 HOST_WIDE_INT
1368 default_vector_alignment (const_tree type)
1370 unsigned HOST_WIDE_INT align = MAX_OFILE_ALIGNMENT;
1371 tree size = TYPE_SIZE (type);
1372 if (tree_fits_uhwi_p (size))
1373 align = tree_to_uhwi (size);
1374 if (align >= MAX_OFILE_ALIGNMENT)
1375 return MAX_OFILE_ALIGNMENT;
1376 return MAX (align, GET_MODE_ALIGNMENT (TYPE_MODE (type)));
1379 /* The default implementation of
1380 TARGET_VECTORIZE_PREFERRED_VECTOR_ALIGNMENT. */
1382 poly_uint64
1383 default_preferred_vector_alignment (const_tree type)
1385 return TYPE_ALIGN (type);
1388 /* By default assume vectors of element TYPE require a multiple of the natural
1389 alignment of TYPE. TYPE is naturally aligned if IS_PACKED is false. */
1390 bool
1391 default_builtin_vector_alignment_reachable (const_tree /*type*/, bool is_packed)
1393 return ! is_packed;
1396 /* By default, assume that a target supports any factor of misalignment
1397 memory access if it supports movmisalign patten.
1398 is_packed is true if the memory access is defined in a packed struct. */
1399 bool
1400 default_builtin_support_vector_misalignment (machine_mode mode,
1401 const_tree type
1402 ATTRIBUTE_UNUSED,
1403 int misalignment
1404 ATTRIBUTE_UNUSED,
1405 bool is_packed
1406 ATTRIBUTE_UNUSED)
1408 if (optab_handler (movmisalign_optab, mode) != CODE_FOR_nothing)
1409 return true;
1410 return false;
1413 /* By default, only attempt to parallelize bitwise operations, and
1414 possibly adds/subtracts using bit-twiddling. */
1416 machine_mode
1417 default_preferred_simd_mode (scalar_mode)
1419 return word_mode;
1422 /* By default do not split reductions further. */
1424 machine_mode
1425 default_split_reduction (machine_mode mode)
1427 return mode;
1430 /* By default only the preferred vector mode is tried. */
1432 unsigned int
1433 default_autovectorize_vector_modes (vector_modes *, bool)
1435 return 0;
1438 /* The default implementation of TARGET_VECTORIZE_RELATED_MODE. */
1440 opt_machine_mode
1441 default_vectorize_related_mode (machine_mode vector_mode,
1442 scalar_mode element_mode,
1443 poly_uint64 nunits)
1445 machine_mode result_mode;
1446 if ((maybe_ne (nunits, 0U)
1447 || multiple_p (GET_MODE_SIZE (vector_mode),
1448 GET_MODE_SIZE (element_mode), &nunits))
1449 && mode_for_vector (element_mode, nunits).exists (&result_mode)
1450 && VECTOR_MODE_P (result_mode)
1451 && targetm.vector_mode_supported_p (result_mode))
1452 return result_mode;
1454 return opt_machine_mode ();
1457 /* By default a vector of integers is used as a mask. */
1459 opt_machine_mode
1460 default_get_mask_mode (machine_mode mode)
1462 return related_int_vector_mode (mode);
1465 /* By default consider masked stores to be expensive. */
1467 bool
1468 default_empty_mask_is_expensive (unsigned ifn)
1470 return ifn == IFN_MASK_STORE;
1473 /* By default, the cost model accumulates three separate costs (prologue,
1474 loop body, and epilogue) for a vectorized loop or block. So allocate an
1475 array of three unsigned ints, set it to zero, and return its address. */
1477 vector_costs *
1478 default_vectorize_create_costs (vec_info *vinfo, bool costing_for_scalar)
1480 return new vector_costs (vinfo, costing_for_scalar);
1483 /* Determine whether or not a pointer mode is valid. Assume defaults
1484 of ptr_mode or Pmode - can be overridden. */
1485 bool
1486 default_valid_pointer_mode (scalar_int_mode mode)
1488 return (mode == ptr_mode || mode == Pmode);
1491 /* Determine whether the memory reference specified by REF may alias
1492 the C libraries errno location. */
1493 bool
1494 default_ref_may_alias_errno (ao_ref *ref)
1496 tree base = ao_ref_base (ref);
1497 /* The default implementation assumes the errno location is
1498 a declaration of type int or is always accessed via a
1499 pointer to int. We assume that accesses to errno are
1500 not deliberately obfuscated (even in conforming ways). */
1501 if (TYPE_UNSIGNED (TREE_TYPE (base))
1502 || TYPE_MODE (TREE_TYPE (base)) != TYPE_MODE (integer_type_node))
1503 return false;
1504 /* The default implementation assumes an errno location declaration
1505 is never defined in the current compilation unit and may not be
1506 aliased by a local variable. */
1507 if (DECL_P (base)
1508 && DECL_EXTERNAL (base)
1509 && !TREE_STATIC (base))
1510 return true;
1511 else if (TREE_CODE (base) == MEM_REF
1512 && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME)
1514 struct ptr_info_def *pi = SSA_NAME_PTR_INFO (TREE_OPERAND (base, 0));
1515 return !pi || pi->pt.anything || pi->pt.nonlocal;
1517 return false;
1520 /* Return the mode for a pointer to a given ADDRSPACE,
1521 defaulting to ptr_mode for all address spaces. */
1523 scalar_int_mode
1524 default_addr_space_pointer_mode (addr_space_t addrspace ATTRIBUTE_UNUSED)
1526 return ptr_mode;
1529 /* Return the mode for an address in a given ADDRSPACE,
1530 defaulting to Pmode for all address spaces. */
1532 scalar_int_mode
1533 default_addr_space_address_mode (addr_space_t addrspace ATTRIBUTE_UNUSED)
1535 return Pmode;
1538 /* Named address space version of valid_pointer_mode.
1539 To match the above, the same modes apply to all address spaces. */
1541 bool
1542 default_addr_space_valid_pointer_mode (scalar_int_mode mode,
1543 addr_space_t as ATTRIBUTE_UNUSED)
1545 return targetm.valid_pointer_mode (mode);
1548 /* Some places still assume that all pointer or address modes are the
1549 standard Pmode and ptr_mode. These optimizations become invalid if
1550 the target actually supports multiple different modes. For now,
1551 we disable such optimizations on such targets, using this function. */
1553 bool
1554 target_default_pointer_address_modes_p (void)
1556 if (targetm.addr_space.address_mode != default_addr_space_address_mode)
1557 return false;
1558 if (targetm.addr_space.pointer_mode != default_addr_space_pointer_mode)
1559 return false;
1561 return true;
1564 /* Named address space version of legitimate_address_p.
1565 By default, all address spaces have the same form. */
1567 bool
1568 default_addr_space_legitimate_address_p (machine_mode mode, rtx mem,
1569 bool strict,
1570 addr_space_t as ATTRIBUTE_UNUSED)
1572 return targetm.legitimate_address_p (mode, mem, strict);
1575 /* Named address space version of LEGITIMIZE_ADDRESS.
1576 By default, all address spaces have the same form. */
1579 default_addr_space_legitimize_address (rtx x, rtx oldx, machine_mode mode,
1580 addr_space_t as ATTRIBUTE_UNUSED)
1582 return targetm.legitimize_address (x, oldx, mode);
1585 /* The default hook for determining if one named address space is a subset of
1586 another and to return which address space to use as the common address
1587 space. */
1589 bool
1590 default_addr_space_subset_p (addr_space_t subset, addr_space_t superset)
1592 return (subset == superset);
1595 /* The default hook for determining if 0 within a named address
1596 space is a valid address. */
1598 bool
1599 default_addr_space_zero_address_valid (addr_space_t as ATTRIBUTE_UNUSED)
1601 return false;
1604 /* The default hook for debugging the address space is to return the
1605 address space number to indicate DW_AT_address_class. */
1607 default_addr_space_debug (addr_space_t as)
1609 return as;
1612 /* The default hook implementation for TARGET_ADDR_SPACE_DIAGNOSE_USAGE.
1613 Don't complain about any address space. */
1615 void
1616 default_addr_space_diagnose_usage (addr_space_t, location_t)
1621 /* The default hook for TARGET_ADDR_SPACE_CONVERT. This hook should never be
1622 called for targets with only a generic address space. */
1625 default_addr_space_convert (rtx op ATTRIBUTE_UNUSED,
1626 tree from_type ATTRIBUTE_UNUSED,
1627 tree to_type ATTRIBUTE_UNUSED)
1629 gcc_unreachable ();
1632 /* The defualt implementation of TARGET_HARD_REGNO_NREGS. */
1634 unsigned int
1635 default_hard_regno_nregs (unsigned int, machine_mode mode)
1637 /* Targets with variable-sized modes must provide their own definition
1638 of this hook. */
1639 return CEIL (GET_MODE_SIZE (mode).to_constant (), UNITS_PER_WORD);
1642 bool
1643 default_hard_regno_scratch_ok (unsigned int regno ATTRIBUTE_UNUSED)
1645 return true;
1648 /* The default implementation of TARGET_MODE_DEPENDENT_ADDRESS_P. */
1650 bool
1651 default_mode_dependent_address_p (const_rtx addr ATTRIBUTE_UNUSED,
1652 addr_space_t addrspace ATTRIBUTE_UNUSED)
1654 return false;
1657 extern bool default_new_address_profitable_p (rtx, rtx);
1660 /* The default implementation of TARGET_NEW_ADDRESS_PROFITABLE_P. */
1662 bool
1663 default_new_address_profitable_p (rtx memref ATTRIBUTE_UNUSED,
1664 rtx_insn *insn ATTRIBUTE_UNUSED,
1665 rtx new_addr ATTRIBUTE_UNUSED)
1667 return true;
1670 bool
1671 default_target_option_valid_attribute_p (tree ARG_UNUSED (fndecl),
1672 tree ARG_UNUSED (name),
1673 tree ARG_UNUSED (args),
1674 int ARG_UNUSED (flags))
1676 warning (OPT_Wattributes,
1677 "target attribute is not supported on this machine");
1679 return false;
1682 bool
1683 default_target_option_pragma_parse (tree ARG_UNUSED (args),
1684 tree ARG_UNUSED (pop_target))
1686 /* If args is NULL the caller is handle_pragma_pop_options (). In that case,
1687 emit no warning because "#pragma GCC pop_target" is valid on targets that
1688 do not have the "target" pragma. */
1689 if (args)
1690 warning (OPT_Wpragmas,
1691 "%<#pragma GCC target%> is not supported for this machine");
1693 return false;
1696 bool
1697 default_target_can_inline_p (tree caller, tree callee)
1699 tree callee_opts = DECL_FUNCTION_SPECIFIC_TARGET (callee);
1700 tree caller_opts = DECL_FUNCTION_SPECIFIC_TARGET (caller);
1701 if (! callee_opts)
1702 callee_opts = target_option_default_node;
1703 if (! caller_opts)
1704 caller_opts = target_option_default_node;
1706 /* If both caller and callee have attributes, assume that if the
1707 pointer is different, the two functions have different target
1708 options since build_target_option_node uses a hash table for the
1709 options. */
1710 return callee_opts == caller_opts;
1713 /* If the machine does not have a case insn that compares the bounds,
1714 this means extra overhead for dispatch tables, which raises the
1715 threshold for using them. */
1717 unsigned int
1718 default_case_values_threshold (void)
1720 return (targetm.have_casesi () ? 4 : 5);
1723 bool
1724 default_have_conditional_execution (void)
1726 return HAVE_conditional_execution;
1729 /* By default we assume that c99 functions are present at the runtime,
1730 but sincos is not. */
1731 bool
1732 default_libc_has_function (enum function_class fn_class,
1733 tree type ATTRIBUTE_UNUSED)
1735 if (fn_class == function_c94
1736 || fn_class == function_c99_misc
1737 || fn_class == function_c99_math_complex)
1738 return true;
1740 return false;
1743 /* By default assume that libc has not a fast implementation. */
1745 bool
1746 default_libc_has_fast_function (int fcode ATTRIBUTE_UNUSED)
1748 return false;
1751 bool
1752 gnu_libc_has_function (enum function_class fn_class ATTRIBUTE_UNUSED,
1753 tree type ATTRIBUTE_UNUSED)
1755 return true;
1758 bool
1759 no_c99_libc_has_function (enum function_class fn_class ATTRIBUTE_UNUSED,
1760 tree type ATTRIBUTE_UNUSED)
1762 return false;
1765 tree
1766 default_builtin_tm_load_store (tree ARG_UNUSED (type))
1768 return NULL_TREE;
1771 /* Compute cost of moving registers to/from memory. */
1774 default_memory_move_cost (machine_mode mode ATTRIBUTE_UNUSED,
1775 reg_class_t rclass ATTRIBUTE_UNUSED,
1776 bool in ATTRIBUTE_UNUSED)
1778 #ifndef MEMORY_MOVE_COST
1779 return (4 + memory_move_secondary_cost (mode, (enum reg_class) rclass, in));
1780 #else
1781 return MEMORY_MOVE_COST (MACRO_MODE (mode), (enum reg_class) rclass, in);
1782 #endif
1785 /* Compute cost of moving data from a register of class FROM to one of
1786 TO, using MODE. */
1789 default_register_move_cost (machine_mode mode ATTRIBUTE_UNUSED,
1790 reg_class_t from ATTRIBUTE_UNUSED,
1791 reg_class_t to ATTRIBUTE_UNUSED)
1793 #ifndef REGISTER_MOVE_COST
1794 return 2;
1795 #else
1796 return REGISTER_MOVE_COST (MACRO_MODE (mode),
1797 (enum reg_class) from, (enum reg_class) to);
1798 #endif
1801 /* The default implementation of TARGET_SLOW_UNALIGNED_ACCESS. */
1803 bool
1804 default_slow_unaligned_access (machine_mode, unsigned int)
1806 return STRICT_ALIGNMENT;
1809 /* The default implementation of TARGET_ESTIMATED_POLY_VALUE. */
1811 HOST_WIDE_INT
1812 default_estimated_poly_value (poly_int64 x, poly_value_estimate_kind)
1814 return x.coeffs[0];
1817 /* For hooks which use the MOVE_RATIO macro, this gives the legacy default
1818 behavior. SPEED_P is true if we are compiling for speed. */
1820 unsigned int
1821 get_move_ratio (bool speed_p ATTRIBUTE_UNUSED)
1823 unsigned int move_ratio;
1824 #ifdef MOVE_RATIO
1825 move_ratio = (unsigned int) MOVE_RATIO (speed_p);
1826 #else
1827 #if defined (HAVE_cpymemqi) || defined (HAVE_cpymemhi) || defined (HAVE_cpymemsi) || defined (HAVE_cpymemdi) || defined (HAVE_cpymemti)
1828 move_ratio = 2;
1829 #else /* No cpymem patterns, pick a default. */
1830 move_ratio = ((speed_p) ? 15 : 3);
1831 #endif
1832 #endif
1833 return move_ratio;
1836 /* Return TRUE if the move_by_pieces/set_by_pieces infrastructure should be
1837 used; return FALSE if the cpymem/setmem optab should be expanded, or
1838 a call to memcpy emitted. */
1840 bool
1841 default_use_by_pieces_infrastructure_p (unsigned HOST_WIDE_INT size,
1842 unsigned int alignment,
1843 enum by_pieces_operation op,
1844 bool speed_p)
1846 unsigned int max_size = 0;
1847 unsigned int ratio = 0;
1849 switch (op)
1851 case CLEAR_BY_PIECES:
1852 max_size = STORE_MAX_PIECES;
1853 ratio = CLEAR_RATIO (speed_p);
1854 break;
1855 case MOVE_BY_PIECES:
1856 max_size = MOVE_MAX_PIECES;
1857 ratio = get_move_ratio (speed_p);
1858 break;
1859 case SET_BY_PIECES:
1860 max_size = STORE_MAX_PIECES;
1861 ratio = SET_RATIO (speed_p);
1862 break;
1863 case STORE_BY_PIECES:
1864 max_size = STORE_MAX_PIECES;
1865 ratio = get_move_ratio (speed_p);
1866 break;
1867 case COMPARE_BY_PIECES:
1868 max_size = COMPARE_MAX_PIECES;
1869 /* Pick a likely default, just as in get_move_ratio. */
1870 ratio = speed_p ? 15 : 3;
1871 break;
1874 return by_pieces_ninsns (size, alignment, max_size + 1, op) < ratio;
1877 /* This hook controls code generation for expanding a memcmp operation by
1878 pieces. Return 1 for the normal pattern of compare/jump after each pair
1879 of loads, or a higher number to reduce the number of branches. */
1882 default_compare_by_pieces_branch_ratio (machine_mode)
1884 return 1;
1887 /* Helper for default_print_patchable_function_entry and other
1888 print_patchable_function_entry hook implementations. */
1890 void
1891 default_print_patchable_function_entry_1 (FILE *file,
1892 unsigned HOST_WIDE_INT
1893 patch_area_size,
1894 bool record_p,
1895 unsigned int flags)
1897 const char *nop_templ = 0;
1898 int code_num;
1899 rtx_insn *my_nop = make_insn_raw (gen_nop ());
1901 /* We use the template alone, relying on the (currently sane) assumption
1902 that the NOP template does not have variable operands. */
1903 code_num = recog_memoized (my_nop);
1904 nop_templ = get_insn_template (code_num, my_nop);
1906 if (record_p && targetm_common.have_named_sections)
1908 char buf[256];
1909 static int patch_area_number;
1910 section *previous_section = in_section;
1911 const char *asm_op = integer_asm_op (POINTER_SIZE_UNITS, false);
1913 gcc_assert (asm_op != NULL);
1914 patch_area_number++;
1915 ASM_GENERATE_INTERNAL_LABEL (buf, "LPFE", patch_area_number);
1917 switch_to_section (get_section ("__patchable_function_entries",
1918 flags, current_function_decl));
1919 assemble_align (POINTER_SIZE);
1920 fputs (asm_op, file);
1921 assemble_name_raw (file, buf);
1922 fputc ('\n', file);
1924 switch_to_section (previous_section);
1925 ASM_OUTPUT_LABEL (file, buf);
1928 unsigned i;
1929 for (i = 0; i < patch_area_size; ++i)
1930 output_asm_insn (nop_templ, NULL);
1933 /* Write PATCH_AREA_SIZE NOPs into the asm outfile FILE around a function
1934 entry. If RECORD_P is true and the target supports named sections,
1935 the location of the NOPs will be recorded in a special object section
1936 called "__patchable_function_entries". This routine may be called
1937 twice per function to put NOPs before and after the function
1938 entry. */
1940 void
1941 default_print_patchable_function_entry (FILE *file,
1942 unsigned HOST_WIDE_INT patch_area_size,
1943 bool record_p)
1945 unsigned int flags = SECTION_WRITE | SECTION_RELRO;
1946 if (HAVE_GAS_SECTION_LINK_ORDER)
1947 flags |= SECTION_LINK_ORDER;
1948 default_print_patchable_function_entry_1 (file, patch_area_size, record_p,
1949 flags);
1952 bool
1953 default_profile_before_prologue (void)
1955 #ifdef PROFILE_BEFORE_PROLOGUE
1956 return true;
1957 #else
1958 return false;
1959 #endif
1962 /* The default implementation of TARGET_PREFERRED_RELOAD_CLASS. */
1964 reg_class_t
1965 default_preferred_reload_class (rtx x ATTRIBUTE_UNUSED,
1966 reg_class_t rclass)
1968 #ifdef PREFERRED_RELOAD_CLASS
1969 return (reg_class_t) PREFERRED_RELOAD_CLASS (x, (enum reg_class) rclass);
1970 #else
1971 return rclass;
1972 #endif
1975 /* The default implementation of TARGET_OUTPUT_PREFERRED_RELOAD_CLASS. */
1977 reg_class_t
1978 default_preferred_output_reload_class (rtx x ATTRIBUTE_UNUSED,
1979 reg_class_t rclass)
1981 return rclass;
1984 /* The default implementation of TARGET_PREFERRED_RENAME_CLASS. */
1985 reg_class_t
1986 default_preferred_rename_class (reg_class_t rclass ATTRIBUTE_UNUSED)
1988 return NO_REGS;
1991 /* The default implementation of TARGET_CLASS_LIKELY_SPILLED_P. */
1993 bool
1994 default_class_likely_spilled_p (reg_class_t rclass)
1996 return (reg_class_size[(int) rclass] == 1);
1999 /* The default implementation of TARGET_CLASS_MAX_NREGS. */
2001 unsigned char
2002 default_class_max_nregs (reg_class_t rclass ATTRIBUTE_UNUSED,
2003 machine_mode mode ATTRIBUTE_UNUSED)
2005 #ifdef CLASS_MAX_NREGS
2006 return (unsigned char) CLASS_MAX_NREGS ((enum reg_class) rclass,
2007 MACRO_MODE (mode));
2008 #else
2009 /* Targets with variable-sized modes must provide their own definition
2010 of this hook. */
2011 unsigned int size = GET_MODE_SIZE (mode).to_constant ();
2012 return (size + UNITS_PER_WORD - 1) / UNITS_PER_WORD;
2013 #endif
2016 /* Determine the debugging unwind mechanism for the target. */
2018 enum unwind_info_type
2019 default_debug_unwind_info (void)
2021 /* If the target wants to force the use of dwarf2 unwind info, let it. */
2022 /* ??? Change all users to the hook, then poison this. */
2023 #ifdef DWARF2_FRAME_INFO
2024 if (DWARF2_FRAME_INFO)
2025 return UI_DWARF2;
2026 #endif
2028 /* Otherwise, only turn it on if dwarf2 debugging is enabled. */
2029 #ifdef DWARF2_DEBUGGING_INFO
2030 if (dwarf_debuginfo_p ())
2031 return UI_DWARF2;
2032 #endif
2034 return UI_NONE;
2037 /* Targets that set NUM_POLY_INT_COEFFS to something greater than 1
2038 must define this hook. */
2040 unsigned int
2041 default_dwarf_poly_indeterminate_value (unsigned int, unsigned int *, int *)
2043 gcc_unreachable ();
2046 /* Determine the correct mode for a Dwarf frame register that represents
2047 register REGNO. */
2049 machine_mode
2050 default_dwarf_frame_reg_mode (int regno)
2052 machine_mode save_mode = reg_raw_mode[regno];
2054 if (targetm.hard_regno_call_part_clobbered (eh_edge_abi.id (),
2055 regno, save_mode))
2056 save_mode = choose_hard_reg_mode (regno, 1, &eh_edge_abi);
2057 return save_mode;
2060 /* To be used by targets where reg_raw_mode doesn't return the right
2061 mode for registers used in apply_builtin_return and apply_builtin_arg. */
2063 fixed_size_mode
2064 default_get_reg_raw_mode (int regno)
2066 /* Targets must override this hook if the underlying register is
2067 variable-sized. */
2068 return as_a <fixed_size_mode> (reg_raw_mode[regno]);
2071 /* Return true if a leaf function should stay leaf even with profiling
2072 enabled. */
2074 bool
2075 default_keep_leaf_when_profiled ()
2077 return false;
2080 /* Return true if the state of option OPTION should be stored in PCH files
2081 and checked by default_pch_valid_p. Store the option's current state
2082 in STATE if so. */
2084 static inline bool
2085 option_affects_pch_p (int option, struct cl_option_state *state)
2087 if ((cl_options[option].flags & CL_TARGET) == 0)
2088 return false;
2089 if ((cl_options[option].flags & CL_PCH_IGNORE) != 0)
2090 return false;
2091 if (option_flag_var (option, &global_options) == &target_flags)
2092 if (targetm.check_pch_target_flags)
2093 return false;
2094 return get_option_state (&global_options, option, state);
2097 /* Default version of get_pch_validity.
2098 By default, every flag difference is fatal; that will be mostly right for
2099 most targets, but completely right for very few. */
2101 void *
2102 default_get_pch_validity (size_t *sz)
2104 struct cl_option_state state;
2105 size_t i;
2106 char *result, *r;
2108 *sz = 2;
2109 if (targetm.check_pch_target_flags)
2110 *sz += sizeof (target_flags);
2111 for (i = 0; i < cl_options_count; i++)
2112 if (option_affects_pch_p (i, &state))
2113 *sz += state.size;
2115 result = r = XNEWVEC (char, *sz);
2116 r[0] = flag_pic;
2117 r[1] = flag_pie;
2118 r += 2;
2119 if (targetm.check_pch_target_flags)
2121 memcpy (r, &target_flags, sizeof (target_flags));
2122 r += sizeof (target_flags);
2125 for (i = 0; i < cl_options_count; i++)
2126 if (option_affects_pch_p (i, &state))
2128 memcpy (r, state.data, state.size);
2129 r += state.size;
2132 return result;
2135 /* Return a message which says that a PCH file was created with a different
2136 setting of OPTION. */
2138 static const char *
2139 pch_option_mismatch (const char *option)
2141 return xasprintf (_("created and used with differing settings of '%s'"),
2142 option);
2145 /* Default version of pch_valid_p. */
2147 const char *
2148 default_pch_valid_p (const void *data_p, size_t len ATTRIBUTE_UNUSED)
2150 struct cl_option_state state;
2151 const char *data = (const char *)data_p;
2152 size_t i;
2154 /* -fpic and -fpie also usually make a PCH invalid. */
2155 if (data[0] != flag_pic)
2156 return _("created and used with different settings of %<-fpic%>");
2157 if (data[1] != flag_pie)
2158 return _("created and used with different settings of %<-fpie%>");
2159 data += 2;
2161 /* Check target_flags. */
2162 if (targetm.check_pch_target_flags)
2164 int tf;
2165 const char *r;
2167 memcpy (&tf, data, sizeof (target_flags));
2168 data += sizeof (target_flags);
2169 r = targetm.check_pch_target_flags (tf);
2170 if (r != NULL)
2171 return r;
2174 for (i = 0; i < cl_options_count; i++)
2175 if (option_affects_pch_p (i, &state))
2177 if (memcmp (data, state.data, state.size) != 0)
2178 return pch_option_mismatch (cl_options[i].opt_text);
2179 data += state.size;
2182 return NULL;
2185 /* Default version of cstore_mode. */
2187 scalar_int_mode
2188 default_cstore_mode (enum insn_code icode)
2190 return as_a <scalar_int_mode> (insn_data[(int) icode].operand[0].mode);
2193 /* Default version of member_type_forces_blk. */
2195 bool
2196 default_member_type_forces_blk (const_tree, machine_mode)
2198 return false;
2201 /* Default version of canonicalize_comparison. */
2203 void
2204 default_canonicalize_comparison (int *, rtx *, rtx *, bool)
2208 /* Default implementation of TARGET_ATOMIC_ASSIGN_EXPAND_FENV. */
2210 void
2211 default_atomic_assign_expand_fenv (tree *, tree *, tree *)
2215 #ifndef PAD_VARARGS_DOWN
2216 #define PAD_VARARGS_DOWN BYTES_BIG_ENDIAN
2217 #endif
2219 /* Build an indirect-ref expression over the given TREE, which represents a
2220 piece of a va_arg() expansion. */
2221 tree
2222 build_va_arg_indirect_ref (tree addr)
2224 addr = build_simple_mem_ref_loc (EXPR_LOCATION (addr), addr);
2225 return addr;
2228 /* The "standard" implementation of va_arg: read the value from the
2229 current (padded) address and increment by the (padded) size. */
2231 tree
2232 std_gimplify_va_arg_expr (tree valist, tree type, gimple_seq *pre_p,
2233 gimple_seq *post_p)
2235 tree addr, t, type_size, rounded_size, valist_tmp;
2236 unsigned HOST_WIDE_INT align, boundary;
2237 bool indirect;
2239 /* All of the alignment and movement below is for args-grow-up machines.
2240 As of 2004, there are only 3 ARGS_GROW_DOWNWARD targets, and they all
2241 implement their own specialized gimplify_va_arg_expr routines. */
2242 if (ARGS_GROW_DOWNWARD)
2243 gcc_unreachable ();
2245 indirect = pass_va_arg_by_reference (type);
2246 if (indirect)
2247 type = build_pointer_type (type);
2249 if (targetm.calls.split_complex_arg
2250 && TREE_CODE (type) == COMPLEX_TYPE
2251 && targetm.calls.split_complex_arg (type))
2253 tree real_part, imag_part;
2255 real_part = std_gimplify_va_arg_expr (valist,
2256 TREE_TYPE (type), pre_p, NULL);
2257 real_part = get_initialized_tmp_var (real_part, pre_p);
2259 imag_part = std_gimplify_va_arg_expr (unshare_expr (valist),
2260 TREE_TYPE (type), pre_p, NULL);
2261 imag_part = get_initialized_tmp_var (imag_part, pre_p);
2263 return build2 (COMPLEX_EXPR, type, real_part, imag_part);
2266 align = PARM_BOUNDARY / BITS_PER_UNIT;
2267 boundary = targetm.calls.function_arg_boundary (TYPE_MODE (type), type);
2269 /* When we align parameter on stack for caller, if the parameter
2270 alignment is beyond MAX_SUPPORTED_STACK_ALIGNMENT, it will be
2271 aligned at MAX_SUPPORTED_STACK_ALIGNMENT. We will match callee
2272 here with caller. */
2273 if (boundary > MAX_SUPPORTED_STACK_ALIGNMENT)
2274 boundary = MAX_SUPPORTED_STACK_ALIGNMENT;
2276 boundary /= BITS_PER_UNIT;
2278 /* Hoist the valist value into a temporary for the moment. */
2279 valist_tmp = get_initialized_tmp_var (valist, pre_p);
2281 /* va_list pointer is aligned to PARM_BOUNDARY. If argument actually
2282 requires greater alignment, we must perform dynamic alignment. */
2283 if (boundary > align
2284 && !TYPE_EMPTY_P (type)
2285 && !integer_zerop (TYPE_SIZE (type)))
2287 t = build2 (MODIFY_EXPR, TREE_TYPE (valist), valist_tmp,
2288 fold_build_pointer_plus_hwi (valist_tmp, boundary - 1));
2289 gimplify_and_add (t, pre_p);
2291 t = build2 (MODIFY_EXPR, TREE_TYPE (valist), valist_tmp,
2292 fold_build2 (BIT_AND_EXPR, TREE_TYPE (valist),
2293 valist_tmp,
2294 build_int_cst (TREE_TYPE (valist), -boundary)));
2295 gimplify_and_add (t, pre_p);
2297 else
2298 boundary = align;
2300 /* If the actual alignment is less than the alignment of the type,
2301 adjust the type accordingly so that we don't assume strict alignment
2302 when dereferencing the pointer. */
2303 boundary *= BITS_PER_UNIT;
2304 if (boundary < TYPE_ALIGN (type))
2306 type = build_variant_type_copy (type);
2307 SET_TYPE_ALIGN (type, boundary);
2310 /* Compute the rounded size of the type. */
2311 type_size = arg_size_in_bytes (type);
2312 rounded_size = round_up (type_size, align);
2314 /* Reduce rounded_size so it's sharable with the postqueue. */
2315 gimplify_expr (&rounded_size, pre_p, post_p, is_gimple_val, fb_rvalue);
2317 /* Get AP. */
2318 addr = valist_tmp;
2319 if (PAD_VARARGS_DOWN && !integer_zerop (rounded_size))
2321 /* Small args are padded downward. */
2322 t = fold_build2_loc (input_location, GT_EXPR, sizetype,
2323 rounded_size, size_int (align));
2324 t = fold_build3 (COND_EXPR, sizetype, t, size_zero_node,
2325 size_binop (MINUS_EXPR, rounded_size, type_size));
2326 addr = fold_build_pointer_plus (addr, t);
2329 /* Compute new value for AP. */
2330 t = fold_build_pointer_plus (valist_tmp, rounded_size);
2331 t = build2 (MODIFY_EXPR, TREE_TYPE (valist), valist, t);
2332 gimplify_and_add (t, pre_p);
2334 addr = fold_convert (build_pointer_type (type), addr);
2336 if (indirect)
2337 addr = build_va_arg_indirect_ref (addr);
2339 return build_va_arg_indirect_ref (addr);
2342 /* An implementation of TARGET_CAN_USE_DOLOOP_P for targets that do
2343 not support nested low-overhead loops. */
2345 bool
2346 can_use_doloop_if_innermost (const widest_int &, const widest_int &,
2347 unsigned int loop_depth, bool)
2349 return loop_depth == 1;
2352 /* Default implementation of TARGET_OPTAB_SUPPORTED_P. */
2354 bool
2355 default_optab_supported_p (int, machine_mode, machine_mode, optimization_type)
2357 return true;
2360 /* Default implementation of TARGET_MAX_NOCE_IFCVT_SEQ_COST. */
2362 unsigned int
2363 default_max_noce_ifcvt_seq_cost (edge e)
2365 bool predictable_p = predictable_edge_p (e);
2367 if (predictable_p)
2369 if (OPTION_SET_P (param_max_rtl_if_conversion_predictable_cost))
2370 return param_max_rtl_if_conversion_predictable_cost;
2372 else
2374 if (OPTION_SET_P (param_max_rtl_if_conversion_unpredictable_cost))
2375 return param_max_rtl_if_conversion_unpredictable_cost;
2378 return BRANCH_COST (true, predictable_p) * COSTS_N_INSNS (3);
2381 /* Default implementation of TARGET_MIN_ARITHMETIC_PRECISION. */
2383 unsigned int
2384 default_min_arithmetic_precision (void)
2386 return WORD_REGISTER_OPERATIONS ? BITS_PER_WORD : BITS_PER_UNIT;
2389 /* Default implementation of TARGET_C_EXCESS_PRECISION. */
2391 enum flt_eval_method
2392 default_excess_precision (enum excess_precision_type ATTRIBUTE_UNUSED)
2394 return FLT_EVAL_METHOD_PROMOTE_TO_FLOAT;
2397 /* Default implementation for
2398 TARGET_STACK_CLASH_PROTECTION_ALLOCA_PROBE_RANGE. */
2399 HOST_WIDE_INT
2400 default_stack_clash_protection_alloca_probe_range (void)
2402 return 0;
2405 /* The default implementation of TARGET_EARLY_REMAT_MODES. */
2407 void
2408 default_select_early_remat_modes (sbitmap)
2412 /* The default implementation of TARGET_PREFERRED_ELSE_VALUE. */
2414 tree
2415 default_preferred_else_value (unsigned, tree type, unsigned, tree *)
2417 return build_zero_cst (type);
2420 /* Default implementation of TARGET_HAVE_SPECULATION_SAFE_VALUE. */
2421 bool
2422 default_have_speculation_safe_value (bool active ATTRIBUTE_UNUSED)
2424 #ifdef HAVE_speculation_barrier
2425 return active ? HAVE_speculation_barrier : true;
2426 #else
2427 return false;
2428 #endif
2430 /* Alternative implementation of TARGET_HAVE_SPECULATION_SAFE_VALUE
2431 that can be used on targets that never have speculative execution. */
2432 bool
2433 speculation_safe_value_not_needed (bool active)
2435 return !active;
2438 /* Default implementation of the speculation-safe-load builtin. This
2439 implementation simply copies val to result and generates a
2440 speculation_barrier insn, if such a pattern is defined. */
2442 default_speculation_safe_value (machine_mode mode ATTRIBUTE_UNUSED,
2443 rtx result, rtx val,
2444 rtx failval ATTRIBUTE_UNUSED)
2446 emit_move_insn (result, val);
2448 #ifdef HAVE_speculation_barrier
2449 /* Assume the target knows what it is doing: if it defines a
2450 speculation barrier, but it is not enabled, then assume that one
2451 isn't needed. */
2452 if (HAVE_speculation_barrier)
2453 emit_insn (gen_speculation_barrier ());
2454 #endif
2456 return result;
2459 /* How many bits to shift in order to access the tag bits.
2460 The default is to store the tag in the top 8 bits of a 64 bit pointer, hence
2461 shifting 56 bits will leave just the tag. */
2462 #define HWASAN_SHIFT (GET_MODE_PRECISION (Pmode) - 8)
2463 #define HWASAN_SHIFT_RTX GEN_INT (HWASAN_SHIFT)
2465 bool
2466 default_memtag_can_tag_addresses ()
2468 return false;
2471 uint8_t
2472 default_memtag_tag_size ()
2474 return 8;
2477 uint8_t
2478 default_memtag_granule_size ()
2480 return 16;
2483 /* The default implementation of TARGET_MEMTAG_INSERT_RANDOM_TAG. */
2485 default_memtag_insert_random_tag (rtx untagged, rtx target)
2487 gcc_assert (param_hwasan_instrument_stack);
2488 if (param_hwasan_random_frame_tag)
2490 rtx fn = init_one_libfunc ("__hwasan_generate_tag");
2491 rtx new_tag = emit_library_call_value (fn, NULL_RTX, LCT_NORMAL, QImode);
2492 return targetm.memtag.set_tag (untagged, new_tag, target);
2494 else
2496 /* NOTE: The kernel API does not have __hwasan_generate_tag exposed.
2497 In the future we may add the option emit random tags with inline
2498 instrumentation instead of function calls. This would be the same
2499 between the kernel and userland. */
2500 return untagged;
2504 /* The default implementation of TARGET_MEMTAG_ADD_TAG. */
2506 default_memtag_add_tag (rtx base, poly_int64 offset, uint8_t tag_offset)
2508 /* Need to look into what the most efficient code sequence is.
2509 This is a code sequence that would be emitted *many* times, so we
2510 want it as small as possible.
2512 There are two places where tag overflow is a question:
2513 - Tagging the shadow stack.
2514 (both tagging and untagging).
2515 - Tagging addressable pointers.
2517 We need to ensure both behaviors are the same (i.e. that the tag that
2518 ends up in a pointer after "overflowing" the tag bits with a tag addition
2519 is the same that ends up in the shadow space).
2521 The aim is that the behavior of tag addition should follow modulo
2522 wrapping in both instances.
2524 The libhwasan code doesn't have any path that increments a pointer's tag,
2525 which means it has no opinion on what happens when a tag increment
2526 overflows (and hence we can choose our own behavior). */
2528 offset += ((uint64_t)tag_offset << HWASAN_SHIFT);
2529 return plus_constant (Pmode, base, offset);
2532 /* The default implementation of TARGET_MEMTAG_SET_TAG. */
2534 default_memtag_set_tag (rtx untagged, rtx tag, rtx target)
2536 gcc_assert (GET_MODE (untagged) == Pmode && GET_MODE (tag) == QImode);
2537 tag = expand_simple_binop (Pmode, ASHIFT, tag, HWASAN_SHIFT_RTX, NULL_RTX,
2538 /* unsignedp = */1, OPTAB_WIDEN);
2539 rtx ret = expand_simple_binop (Pmode, IOR, untagged, tag, target,
2540 /* unsignedp = */1, OPTAB_DIRECT);
2541 gcc_assert (ret);
2542 return ret;
2545 /* The default implementation of TARGET_MEMTAG_EXTRACT_TAG. */
2547 default_memtag_extract_tag (rtx tagged_pointer, rtx target)
2549 rtx tag = expand_simple_binop (Pmode, LSHIFTRT, tagged_pointer,
2550 HWASAN_SHIFT_RTX, target,
2551 /* unsignedp = */0,
2552 OPTAB_DIRECT);
2553 rtx ret = gen_lowpart (QImode, tag);
2554 gcc_assert (ret);
2555 return ret;
2558 /* The default implementation of TARGET_MEMTAG_UNTAGGED_POINTER. */
2560 default_memtag_untagged_pointer (rtx tagged_pointer, rtx target)
2562 rtx tag_mask = gen_int_mode ((HOST_WIDE_INT_1U << HWASAN_SHIFT) - 1, Pmode);
2563 rtx untagged_base = expand_simple_binop (Pmode, AND, tagged_pointer,
2564 tag_mask, target, true,
2565 OPTAB_DIRECT);
2566 gcc_assert (untagged_base);
2567 return untagged_base;
2570 /* The default implementation of TARGET_GCOV_TYPE_SIZE. */
2571 HOST_WIDE_INT
2572 default_gcov_type_size (void)
2574 return TYPE_PRECISION (long_long_integer_type_node) > 32 ? 64 : 32;
2577 #include "gt-targhooks.h"