1 /* Default target hook functions.
2 Copyright (C) 2003, 2004, 2005, 2007, 2008, 2009
3 Free Software Foundation, Inc.
5 This file is part of GCC.
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
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
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/>. */
21 /* The migration of target macros to target hooks works as follows:
23 1. Create a target hook that uses the existing target macros to
24 implement the same functionality.
26 2. Convert all the MI files to use the hook instead of the macro.
28 3. Repeat for a majority of the remaining target macros. This will
31 4. Tell target maintainers to start migrating.
33 5. Eventually convert the backends to override the hook instead of
34 defining the macros. This will take some time too.
36 6. TBD when, poison the macros. Unmigrated targets will break at
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.
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.
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. */
52 #include "coretypes.h"
63 #include "target-def.h"
65 #include "hard-reg-set.h"
72 default_legitimate_address_p (enum machine_mode mode ATTRIBUTE_UNUSED,
73 rtx addr ATTRIBUTE_UNUSED,
74 bool strict ATTRIBUTE_UNUSED)
76 #ifdef GO_IF_LEGITIMATE_ADDRESS
77 /* Defer to the old implementation using a goto. */
79 return strict_memory_address_p (mode, addr);
81 return memory_address_p (mode, addr);
88 default_external_libcall (rtx fun ATTRIBUTE_UNUSED)
90 #ifdef ASM_OUTPUT_EXTERNAL_LIBCALL
91 ASM_OUTPUT_EXTERNAL_LIBCALL(asm_out_file, fun);
96 default_unspec_may_trap_p (const_rtx x, unsigned flags)
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))
106 for (i = 0; i < XVECLEN (x, 0); ++i)
108 if (may_trap_p_1 (XVECEXP (x, 0, i), flags))
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)
126 default_promote_function_mode_always_promote (const_tree type,
127 enum machine_mode mode,
129 const_tree funtype ATTRIBUTE_UNUSED,
130 int for_return ATTRIBUTE_UNUSED)
132 return promote_mode (type, mode, punsignedp);
137 default_cc_modes_compatible (enum machine_mode m1, enum machine_mode m2)
145 default_return_in_memory (const_tree type,
146 const_tree fntype ATTRIBUTE_UNUSED)
148 return (TYPE_MODE (type) == BLKmode);
152 default_legitimize_address (rtx x, rtx orig_x ATTRIBUTE_UNUSED,
153 enum machine_mode mode ATTRIBUTE_UNUSED)
159 default_expand_builtin_saveregs (void)
161 error ("__builtin_saveregs not supported by this target");
166 default_setup_incoming_varargs (CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
167 enum machine_mode mode ATTRIBUTE_UNUSED,
168 tree type ATTRIBUTE_UNUSED,
169 int *pretend_arg_size ATTRIBUTE_UNUSED,
170 int second_time ATTRIBUTE_UNUSED)
174 /* The default implementation of TARGET_BUILTIN_SETJMP_FRAME_VALUE. */
177 default_builtin_setjmp_frame_value (void)
179 return virtual_stack_vars_rtx;
182 /* Generic hook that takes a CUMULATIVE_ARGS pointer and returns false. */
185 hook_bool_CUMULATIVE_ARGS_false (CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED)
191 default_pretend_outgoing_varargs_named (CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED)
193 return (targetm.calls.setup_incoming_varargs
194 != default_setup_incoming_varargs);
198 default_eh_return_filter_mode (void)
200 return targetm.unwind_word_mode ();
204 default_libgcc_cmp_return_mode (void)
210 default_libgcc_shift_count_mode (void)
216 default_unwind_word_mode (void)
221 /* The default implementation of TARGET_SHIFT_TRUNCATION_MASK. */
223 unsigned HOST_WIDE_INT
224 default_shift_truncation_mask (enum machine_mode mode)
226 return SHIFT_COUNT_TRUNCATED ? GET_MODE_BITSIZE (mode) - 1 : 0;
229 /* The default implementation of TARGET_MIN_DIVISIONS_FOR_RECIP_MUL. */
232 default_min_divisions_for_recip_mul (enum machine_mode mode ATTRIBUTE_UNUSED)
234 return have_insn_for (DIV, mode) ? 3 : 2;
237 /* The default implementation of TARGET_MODE_REP_EXTENDED. */
240 default_mode_rep_extended (enum machine_mode mode ATTRIBUTE_UNUSED,
241 enum machine_mode mode_rep ATTRIBUTE_UNUSED)
246 /* Generic hook that takes a CUMULATIVE_ARGS pointer and returns true. */
249 hook_bool_CUMULATIVE_ARGS_true (CUMULATIVE_ARGS * a ATTRIBUTE_UNUSED)
254 /* Return machine mode for non-standard suffix
255 or VOIDmode if non-standard suffixes are unsupported. */
257 default_mode_for_suffix (char suffix ATTRIBUTE_UNUSED)
262 /* The generic C++ ABI specifies this is a 64-bit value. */
264 default_cxx_guard_type (void)
266 return long_long_integer_type_node;
270 /* Returns the size of the cookie to use when allocating an array
271 whose elements have the indicated TYPE. Assumes that it is already
272 known that a cookie is needed. */
275 default_cxx_get_cookie_size (tree type)
279 /* We need to allocate an additional max (sizeof (size_t), alignof
280 (true_type)) bytes. */
284 sizetype_size = size_in_bytes (sizetype);
285 type_align = size_int (TYPE_ALIGN_UNIT (type));
286 if (INT_CST_LT_UNSIGNED (type_align, sizetype_size))
287 cookie_size = sizetype_size;
289 cookie_size = type_align;
294 /* Return true if a parameter must be passed by reference. This version
295 of the TARGET_PASS_BY_REFERENCE hook uses just MUST_PASS_IN_STACK. */
298 hook_pass_by_reference_must_pass_in_stack (CUMULATIVE_ARGS *c ATTRIBUTE_UNUSED,
299 enum machine_mode mode ATTRIBUTE_UNUSED, const_tree type ATTRIBUTE_UNUSED,
300 bool named_arg ATTRIBUTE_UNUSED)
302 return targetm.calls.must_pass_in_stack (mode, type);
305 /* Return true if a parameter follows callee copies conventions. This
306 version of the hook is true for all named arguments. */
309 hook_callee_copies_named (CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
310 enum machine_mode mode ATTRIBUTE_UNUSED,
311 const_tree type ATTRIBUTE_UNUSED, bool named)
316 /* Emit any directives required to unwind this instruction. */
319 default_unwind_emit (FILE * stream ATTRIBUTE_UNUSED,
320 rtx insn ATTRIBUTE_UNUSED)
322 /* Should never happen. */
326 /* True if MODE is valid for the target. By "valid", we mean able to
327 be manipulated in non-trivial ways. In particular, this means all
328 the arithmetic is supported.
330 By default we guess this means that any C type is supported. If
331 we can't map the mode back to a type that would be available in C,
332 then reject it. Special case, here, is the double-word arithmetic
333 supported by optabs.c. */
336 default_scalar_mode_supported_p (enum machine_mode mode)
338 int precision = GET_MODE_PRECISION (mode);
340 switch (GET_MODE_CLASS (mode))
342 case MODE_PARTIAL_INT:
344 if (precision == CHAR_TYPE_SIZE)
346 if (precision == SHORT_TYPE_SIZE)
348 if (precision == INT_TYPE_SIZE)
350 if (precision == LONG_TYPE_SIZE)
352 if (precision == LONG_LONG_TYPE_SIZE)
354 if (precision == 2 * BITS_PER_WORD)
359 if (precision == FLOAT_TYPE_SIZE)
361 if (precision == DOUBLE_TYPE_SIZE)
363 if (precision == LONG_DOUBLE_TYPE_SIZE)
367 case MODE_DECIMAL_FLOAT:
379 /* True if the target supports decimal floating point. */
382 default_decimal_float_supported_p (void)
384 return ENABLE_DECIMAL_FLOAT;
387 /* True if the target supports fixed-point arithmetic. */
390 default_fixed_point_supported_p (void)
392 return ENABLE_FIXED_POINT;
395 /* NULL if INSN insn is valid within a low-overhead loop, otherwise returns
398 This function checks whether a given INSN is valid within a low-overhead
399 loop. If INSN is invalid it returns the reason for that, otherwise it
400 returns NULL. A called function may clobber any special registers required
401 for low-overhead looping. Additionally, some targets (eg, PPC) use the count
402 register for branch on table instructions. We reject the doloop pattern in
406 default_invalid_within_doloop (const_rtx insn)
409 return "Function call in loop.";
411 if (JUMP_TABLE_DATA_P (insn))
412 return "Computed branch in the loop.";
417 /* Mapping of builtin functions to vectorized variants. */
420 default_builtin_vectorized_function (unsigned int fn ATTRIBUTE_UNUSED,
421 tree type_out ATTRIBUTE_UNUSED,
422 tree type_in ATTRIBUTE_UNUSED)
427 /* Vectorized conversion. */
430 default_builtin_vectorized_conversion (unsigned int code ATTRIBUTE_UNUSED,
431 tree type ATTRIBUTE_UNUSED)
439 default_builtin_reciprocal (unsigned int fn ATTRIBUTE_UNUSED,
440 bool md_fn ATTRIBUTE_UNUSED,
441 bool sqrt ATTRIBUTE_UNUSED)
447 hook_bool_CUMULATIVE_ARGS_mode_tree_bool_false (
448 CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
449 enum machine_mode mode ATTRIBUTE_UNUSED,
450 const_tree type ATTRIBUTE_UNUSED, bool named ATTRIBUTE_UNUSED)
456 hook_bool_CUMULATIVE_ARGS_mode_tree_bool_true (
457 CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
458 enum machine_mode mode ATTRIBUTE_UNUSED,
459 const_tree type ATTRIBUTE_UNUSED, bool named ATTRIBUTE_UNUSED)
465 hook_int_CUMULATIVE_ARGS_mode_tree_bool_0 (
466 CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
467 enum machine_mode mode ATTRIBUTE_UNUSED,
468 tree type ATTRIBUTE_UNUSED, bool named ATTRIBUTE_UNUSED)
474 hook_void_bitmap (bitmap regs ATTRIBUTE_UNUSED)
479 hook_invalid_arg_for_unprototyped_fn (
480 const_tree typelist ATTRIBUTE_UNUSED,
481 const_tree funcdecl ATTRIBUTE_UNUSED,
482 const_tree val ATTRIBUTE_UNUSED)
487 /* Initialize the stack protection decls. */
489 /* Stack protection related decls living in libgcc. */
490 static GTY(()) tree stack_chk_guard_decl;
493 default_stack_protect_guard (void)
495 tree t = stack_chk_guard_decl;
499 t = build_decl (UNKNOWN_LOCATION,
500 VAR_DECL, get_identifier ("__stack_chk_guard"),
504 DECL_EXTERNAL (t) = 1;
506 TREE_THIS_VOLATILE (t) = 1;
507 DECL_ARTIFICIAL (t) = 1;
508 DECL_IGNORED_P (t) = 1;
510 stack_chk_guard_decl = t;
516 static GTY(()) tree stack_chk_fail_decl;
519 default_external_stack_protect_fail (void)
521 tree t = stack_chk_fail_decl;
525 t = build_function_type_list (void_type_node, NULL_TREE);
526 t = build_decl (UNKNOWN_LOCATION,
527 FUNCTION_DECL, get_identifier ("__stack_chk_fail"), t);
530 DECL_EXTERNAL (t) = 1;
532 TREE_THIS_VOLATILE (t) = 1;
533 TREE_NOTHROW (t) = 1;
534 DECL_ARTIFICIAL (t) = 1;
535 DECL_IGNORED_P (t) = 1;
536 DECL_VISIBILITY (t) = VISIBILITY_DEFAULT;
537 DECL_VISIBILITY_SPECIFIED (t) = 1;
539 stack_chk_fail_decl = t;
542 return build_call_expr (t, 0);
546 default_hidden_stack_protect_fail (void)
548 #ifndef HAVE_GAS_HIDDEN
549 return default_external_stack_protect_fail ();
551 tree t = stack_chk_fail_decl;
554 return default_external_stack_protect_fail ();
558 t = build_function_type_list (void_type_node, NULL_TREE);
559 t = build_decl (UNKNOWN_LOCATION, FUNCTION_DECL,
560 get_identifier ("__stack_chk_fail_local"), t);
563 DECL_EXTERNAL (t) = 1;
565 TREE_THIS_VOLATILE (t) = 1;
566 TREE_NOTHROW (t) = 1;
567 DECL_ARTIFICIAL (t) = 1;
568 DECL_IGNORED_P (t) = 1;
569 DECL_VISIBILITY_SPECIFIED (t) = 1;
570 DECL_VISIBILITY (t) = VISIBILITY_HIDDEN;
572 stack_chk_fail_decl = t;
575 return build_call_expr (t, 0);
580 hook_bool_const_rtx_commutative_p (const_rtx x,
581 int outer_code ATTRIBUTE_UNUSED)
583 return COMMUTATIVE_P (x);
587 default_function_value (const_tree ret_type ATTRIBUTE_UNUSED,
588 const_tree fn_decl_or_type,
589 bool outgoing ATTRIBUTE_UNUSED)
591 /* The old interface doesn't handle receiving the function type. */
593 && !DECL_P (fn_decl_or_type))
594 fn_decl_or_type = NULL;
596 #ifdef FUNCTION_OUTGOING_VALUE
598 return FUNCTION_OUTGOING_VALUE (ret_type, fn_decl_or_type);
601 #ifdef FUNCTION_VALUE
602 return FUNCTION_VALUE (ret_type, fn_decl_or_type);
609 default_libcall_value (enum machine_mode mode, rtx fun ATTRIBUTE_UNUSED)
611 return LIBCALL_VALUE (mode);
615 default_internal_arg_pointer (void)
617 /* If the reg that the virtual arg pointer will be translated into is
618 not a fixed reg or is the stack pointer, make a copy of the virtual
619 arg pointer, and address parms via the copy. The frame pointer is
620 considered fixed even though it is not marked as such. */
621 if ((ARG_POINTER_REGNUM == STACK_POINTER_REGNUM
622 || ! (fixed_regs[ARG_POINTER_REGNUM]
623 || ARG_POINTER_REGNUM == FRAME_POINTER_REGNUM)))
624 return copy_to_reg (virtual_incoming_args_rtx);
626 return virtual_incoming_args_rtx;
630 default_branch_target_register_class (void)
635 #ifdef IRA_COVER_CLASSES
636 const enum reg_class *
637 default_ira_cover_classes (void)
639 static enum reg_class classes[] = IRA_COVER_CLASSES;
645 default_secondary_reload (bool in_p ATTRIBUTE_UNUSED, rtx x ATTRIBUTE_UNUSED,
646 enum reg_class reload_class ATTRIBUTE_UNUSED,
647 enum machine_mode reload_mode ATTRIBUTE_UNUSED,
648 secondary_reload_info *sri)
650 enum reg_class rclass = NO_REGS;
652 if (sri->prev_sri && sri->prev_sri->t_icode != CODE_FOR_nothing)
654 sri->icode = sri->prev_sri->t_icode;
657 #ifdef SECONDARY_INPUT_RELOAD_CLASS
659 rclass = SECONDARY_INPUT_RELOAD_CLASS (reload_class, reload_mode, x);
661 #ifdef SECONDARY_OUTPUT_RELOAD_CLASS
663 rclass = SECONDARY_OUTPUT_RELOAD_CLASS (reload_class, reload_mode, x);
665 if (rclass != NO_REGS)
667 enum insn_code icode = (in_p ? reload_in_optab[(int) reload_mode]
668 : reload_out_optab[(int) reload_mode]);
670 if (icode != CODE_FOR_nothing
671 && insn_data[(int) icode].operand[in_p].predicate
672 && ! insn_data[(int) icode].operand[in_p].predicate (x, reload_mode))
673 icode = CODE_FOR_nothing;
674 else if (icode != CODE_FOR_nothing)
676 const char *insn_constraint, *scratch_constraint;
677 char insn_letter, scratch_letter;
678 enum reg_class insn_class, scratch_class;
680 gcc_assert (insn_data[(int) icode].n_operands == 3);
681 insn_constraint = insn_data[(int) icode].operand[!in_p].constraint;
682 if (!*insn_constraint)
683 insn_class = ALL_REGS;
688 gcc_assert (*insn_constraint == '=');
691 insn_letter = *insn_constraint;
693 = (insn_letter == 'r' ? GENERAL_REGS
694 : REG_CLASS_FROM_CONSTRAINT ((unsigned char) insn_letter,
696 gcc_assert (insn_class != NO_REGS);
699 scratch_constraint = insn_data[(int) icode].operand[2].constraint;
700 /* The scratch register's constraint must start with "=&",
701 except for an input reload, where only "=" is necessary,
702 and where it might be beneficial to re-use registers from
704 gcc_assert (scratch_constraint[0] == '='
705 && (in_p || scratch_constraint[1] == '&'));
706 scratch_constraint++;
707 if (*scratch_constraint == '&')
708 scratch_constraint++;
709 scratch_letter = *scratch_constraint;
711 = (scratch_letter == 'r' ? GENERAL_REGS
712 : REG_CLASS_FROM_CONSTRAINT ((unsigned char) scratch_letter,
713 scratch_constraint));
715 if (reg_class_subset_p (reload_class, insn_class))
717 gcc_assert (scratch_class == rclass);
724 if (rclass == NO_REGS)
727 sri->t_icode = icode;
733 default_handle_c_option (size_t code ATTRIBUTE_UNUSED,
734 const char *arg ATTRIBUTE_UNUSED,
735 int value ATTRIBUTE_UNUSED)
740 /* By default, if flag_pic is true, then neither local nor global relocs
741 should be placed in readonly memory. */
744 default_reloc_rw_mask (void)
746 return flag_pic ? 3 : 0;
749 /* By default, do no modification. */
750 tree default_mangle_decl_assembler_name (tree decl ATTRIBUTE_UNUSED,
757 default_builtin_vector_alignment_reachable (const_tree type, bool is_packed)
762 /* Assuming that types whose size is > pointer-size are not guaranteed to be
763 naturally aligned. */
764 if (tree_int_cst_compare (TYPE_SIZE (type), bitsize_int (POINTER_SIZE)) > 0)
767 /* Assuming that types whose size is <= pointer-size
768 are naturally aligned. */
773 default_hard_regno_scratch_ok (unsigned int regno ATTRIBUTE_UNUSED)
779 default_target_option_valid_attribute_p (tree ARG_UNUSED (fndecl),
780 tree ARG_UNUSED (name),
781 tree ARG_UNUSED (args),
782 int ARG_UNUSED (flags))
784 warning (OPT_Wattributes,
785 "target attribute is not supported on this machine");
791 default_target_option_pragma_parse (tree ARG_UNUSED (args),
792 tree ARG_UNUSED (pop_target))
794 warning (OPT_Wpragmas,
795 "#pragma GCC target is not supported for this machine");
801 default_target_can_inline_p (tree caller, tree callee)
804 tree callee_opts = DECL_FUNCTION_SPECIFIC_TARGET (callee);
805 tree caller_opts = DECL_FUNCTION_SPECIFIC_TARGET (caller);
807 /* If callee has no option attributes, then it is ok to inline */
811 /* If caller has no option attributes, but callee does then it is not ok to
813 else if (!caller_opts)
816 /* If both caller and callee have attributes, assume that if the pointer is
817 different, the the two functions have different target options since
818 build_target_option_node uses a hash table for the options. */
820 ret = (callee_opts == caller_opts);
826 # define HAVE_casesi 0
829 /* If the machine does not have a case insn that compares the bounds,
830 this means extra overhead for dispatch tables, which raises the
831 threshold for using them. */
833 unsigned int default_case_values_threshold (void)
835 return (HAVE_casesi ? 4 : 5);
838 #include "gt-targhooks.h"