1 /* Default target hook functions.
2 Copyright (C) 2003, 2004, 2005, 2007 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 2, or (at your option) any later
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
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING. If not, write to the Free
18 Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
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_external_libcall (rtx fun ATTRIBUTE_UNUSED)
74 #ifdef ASM_OUTPUT_EXTERNAL_LIBCALL
75 ASM_OUTPUT_EXTERNAL_LIBCALL(asm_out_file, fun);
80 default_cc_modes_compatible (enum machine_mode m1, enum machine_mode m2)
88 default_return_in_memory (tree type,
89 tree fntype ATTRIBUTE_UNUSED)
91 #ifndef RETURN_IN_MEMORY
92 return (TYPE_MODE (type) == BLKmode);
94 return RETURN_IN_MEMORY (type);
98 /* APPLE LOCAL begin radar 4781080 */
100 default_objc_fpreturn_msgcall (tree type, bool no_long_double)
102 #ifndef OBJC_FPRETURN_MSGCALL
103 return type == NULL_TREE && no_long_double;
105 return OBJC_FPRETURN_MSGCALL (type, no_long_double);
108 /* APPLE LOCAL end radar 4781080 */
111 default_expand_builtin_saveregs (void)
113 error ("__builtin_saveregs not supported by this target");
118 default_setup_incoming_varargs (CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
119 enum machine_mode mode ATTRIBUTE_UNUSED,
120 tree type ATTRIBUTE_UNUSED,
121 int *pretend_arg_size ATTRIBUTE_UNUSED,
122 int second_time ATTRIBUTE_UNUSED)
126 /* The default implementation of TARGET_BUILTIN_SETJMP_FRAME_VALUE. */
129 default_builtin_setjmp_frame_value (void)
131 return virtual_stack_vars_rtx;
134 /* Generic hook that takes a CUMULATIVE_ARGS pointer and returns false. */
137 hook_bool_CUMULATIVE_ARGS_false (CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED)
143 default_pretend_outgoing_varargs_named (CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED)
145 return (targetm.calls.setup_incoming_varargs
146 != default_setup_incoming_varargs);
150 default_eh_return_filter_mode (void)
155 /* The default implementation of TARGET_SHIFT_TRUNCATION_MASK. */
157 unsigned HOST_WIDE_INT
158 default_shift_truncation_mask (enum machine_mode mode)
160 return SHIFT_COUNT_TRUNCATED ? GET_MODE_BITSIZE (mode) - 1 : 0;
163 /* The default implementation of TARGET_MIN_DIVISIONS_FOR_RECIP_MUL. */
166 default_min_divisions_for_recip_mul (enum machine_mode mode ATTRIBUTE_UNUSED)
168 return have_insn_for (DIV, mode) ? 3 : 2;
171 /* The default implementation of TARGET_MODE_REP_EXTENDED. */
174 default_mode_rep_extended (enum machine_mode mode ATTRIBUTE_UNUSED,
175 enum machine_mode mode_rep ATTRIBUTE_UNUSED)
180 /* Generic hook that takes a CUMULATIVE_ARGS pointer and returns true. */
183 hook_bool_CUMULATIVE_ARGS_true (CUMULATIVE_ARGS * a ATTRIBUTE_UNUSED)
189 /* The generic C++ ABI specifies this is a 64-bit value. */
191 default_cxx_guard_type (void)
193 return long_long_integer_type_node;
197 /* Returns the size of the cookie to use when allocating an array
198 whose elements have the indicated TYPE. Assumes that it is already
199 known that a cookie is needed. */
202 default_cxx_get_cookie_size (tree type)
206 /* We need to allocate an additional max (sizeof (size_t), alignof
207 (true_type)) bytes. */
211 sizetype_size = size_in_bytes (sizetype);
212 type_align = size_int (TYPE_ALIGN_UNIT (type));
213 if (INT_CST_LT_UNSIGNED (type_align, sizetype_size))
214 cookie_size = sizetype_size;
216 cookie_size = type_align;
221 /* Return true if a parameter must be passed by reference. This version
222 of the TARGET_PASS_BY_REFERENCE hook uses just MUST_PASS_IN_STACK. */
225 hook_pass_by_reference_must_pass_in_stack (CUMULATIVE_ARGS *c ATTRIBUTE_UNUSED,
226 enum machine_mode mode ATTRIBUTE_UNUSED, tree type ATTRIBUTE_UNUSED,
227 bool named_arg ATTRIBUTE_UNUSED)
229 return targetm.calls.must_pass_in_stack (mode, type);
232 /* Return true if a parameter follows callee copies conventions. This
233 version of the hook is true for all named arguments. */
236 hook_callee_copies_named (CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
237 enum machine_mode mode ATTRIBUTE_UNUSED,
238 tree type ATTRIBUTE_UNUSED, bool named)
243 /* Emit any directives required to unwind this instruction. */
246 default_unwind_emit (FILE * stream ATTRIBUTE_UNUSED,
247 rtx insn ATTRIBUTE_UNUSED)
249 /* Should never happen. */
253 /* True if MODE is valid for the target. By "valid", we mean able to
254 be manipulated in non-trivial ways. In particular, this means all
255 the arithmetic is supported.
257 By default we guess this means that any C type is supported. If
258 we can't map the mode back to a type that would be available in C,
259 then reject it. Special case, here, is the double-word arithmetic
260 supported by optabs.c. */
263 default_scalar_mode_supported_p (enum machine_mode mode)
265 int precision = GET_MODE_PRECISION (mode);
267 switch (GET_MODE_CLASS (mode))
269 case MODE_PARTIAL_INT:
271 if (precision == CHAR_TYPE_SIZE)
273 if (precision == SHORT_TYPE_SIZE)
275 if (precision == INT_TYPE_SIZE)
277 if (precision == LONG_TYPE_SIZE)
279 if (precision == LONG_LONG_TYPE_SIZE)
281 if (precision == 2 * BITS_PER_WORD)
286 if (precision == FLOAT_TYPE_SIZE)
288 if (precision == DOUBLE_TYPE_SIZE)
290 if (precision == LONG_DOUBLE_TYPE_SIZE)
294 case MODE_DECIMAL_FLOAT:
302 /* True if the target supports decimal floating point. */
305 default_decimal_float_supported_p (void)
307 return ENABLE_DECIMAL_FLOAT;
310 /* NULL if INSN insn is valid within a low-overhead loop, otherwise returns
313 This function checks whether a given INSN is valid within a low-overhead
314 loop. If INSN is invalid it returns the reason for that, otherwise it
315 returns NULL. A called function may clobber any special registers required
316 for low-overhead looping. Additionally, some targets (eg, PPC) use the count
317 register for branch on table instructions. We reject the doloop pattern in
321 default_invalid_within_doloop (rtx insn)
324 return "Function call in loop.";
327 && (GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC
328 || GET_CODE (PATTERN (insn)) == ADDR_VEC))
329 return "Computed branch in the loop.";
335 hook_bool_CUMULATIVE_ARGS_mode_tree_bool_false (
336 CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
337 enum machine_mode mode ATTRIBUTE_UNUSED,
338 tree type ATTRIBUTE_UNUSED, bool named ATTRIBUTE_UNUSED)
344 hook_bool_CUMULATIVE_ARGS_mode_tree_bool_true (
345 CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
346 enum machine_mode mode ATTRIBUTE_UNUSED,
347 tree type ATTRIBUTE_UNUSED, bool named ATTRIBUTE_UNUSED)
353 hook_int_CUMULATIVE_ARGS_mode_tree_bool_0 (
354 CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
355 enum machine_mode mode ATTRIBUTE_UNUSED,
356 tree type ATTRIBUTE_UNUSED, bool named ATTRIBUTE_UNUSED)
362 hook_void_bitmap (bitmap regs ATTRIBUTE_UNUSED)
367 hook_invalid_arg_for_unprototyped_fn (
368 tree typelist ATTRIBUTE_UNUSED,
369 tree funcdecl ATTRIBUTE_UNUSED,
370 tree val ATTRIBUTE_UNUSED)
375 /* Initialize the stack protection decls. */
377 /* Stack protection related decls living in libgcc. */
378 static GTY(()) tree stack_chk_guard_decl;
381 default_stack_protect_guard (void)
383 tree t = stack_chk_guard_decl;
387 t = build_decl (VAR_DECL, get_identifier ("__stack_chk_guard"),
391 DECL_EXTERNAL (t) = 1;
393 TREE_THIS_VOLATILE (t) = 1;
394 DECL_ARTIFICIAL (t) = 1;
395 DECL_IGNORED_P (t) = 1;
397 stack_chk_guard_decl = t;
403 static GTY(()) tree stack_chk_fail_decl;
406 default_external_stack_protect_fail (void)
408 tree t = stack_chk_fail_decl;
412 t = build_function_type_list (void_type_node, NULL_TREE);
413 t = build_decl (FUNCTION_DECL, get_identifier ("__stack_chk_fail"), t);
416 DECL_EXTERNAL (t) = 1;
418 TREE_THIS_VOLATILE (t) = 1;
419 TREE_NOTHROW (t) = 1;
420 DECL_ARTIFICIAL (t) = 1;
421 DECL_IGNORED_P (t) = 1;
422 DECL_VISIBILITY (t) = VISIBILITY_DEFAULT;
423 DECL_VISIBILITY_SPECIFIED (t) = 1;
425 stack_chk_fail_decl = t;
428 return build_function_call_expr (t, NULL_TREE);
432 default_hidden_stack_protect_fail (void)
434 #ifndef HAVE_GAS_HIDDEN
435 return default_external_stack_protect_fail ();
437 tree t = stack_chk_fail_decl;
440 return default_external_stack_protect_fail ();
444 t = build_function_type_list (void_type_node, NULL_TREE);
445 t = build_decl (FUNCTION_DECL,
446 get_identifier ("__stack_chk_fail_local"), t);
449 DECL_EXTERNAL (t) = 1;
451 TREE_THIS_VOLATILE (t) = 1;
452 TREE_NOTHROW (t) = 1;
453 DECL_ARTIFICIAL (t) = 1;
454 DECL_IGNORED_P (t) = 1;
455 DECL_VISIBILITY_SPECIFIED (t) = 1;
456 DECL_VISIBILITY (t) = VISIBILITY_HIDDEN;
458 stack_chk_fail_decl = t;
461 return build_function_call_expr (t, NULL_TREE);
466 hook_bool_rtx_commutative_p (rtx x, int outer_code ATTRIBUTE_UNUSED)
468 return COMMUTATIVE_P (x);
472 default_function_value (tree ret_type ATTRIBUTE_UNUSED,
473 tree fn_decl_or_type,
474 bool outgoing ATTRIBUTE_UNUSED)
476 /* The old interface doesn't handle receiving the function type. */
478 && !DECL_P (fn_decl_or_type))
479 fn_decl_or_type = NULL;
481 #ifdef FUNCTION_OUTGOING_VALUE
483 return FUNCTION_OUTGOING_VALUE (ret_type, fn_decl_or_type);
486 #ifdef FUNCTION_VALUE
487 return FUNCTION_VALUE (ret_type, fn_decl_or_type);
494 default_internal_arg_pointer (void)
496 /* If the reg that the virtual arg pointer will be translated into is
497 not a fixed reg or is the stack pointer, make a copy of the virtual
498 arg pointer, and address parms via the copy. The frame pointer is
499 considered fixed even though it is not marked as such. */
500 if ((ARG_POINTER_REGNUM == STACK_POINTER_REGNUM
501 || ! (fixed_regs[ARG_POINTER_REGNUM]
502 || ARG_POINTER_REGNUM == FRAME_POINTER_REGNUM)))
503 return copy_to_reg (virtual_incoming_args_rtx);
505 return virtual_incoming_args_rtx;
509 default_secondary_reload (bool in_p ATTRIBUTE_UNUSED, rtx x ATTRIBUTE_UNUSED,
510 enum reg_class reload_class ATTRIBUTE_UNUSED,
511 enum machine_mode reload_mode ATTRIBUTE_UNUSED,
512 secondary_reload_info *sri)
514 enum reg_class class = NO_REGS;
516 if (sri->prev_sri && sri->prev_sri->t_icode != CODE_FOR_nothing)
518 sri->icode = sri->prev_sri->t_icode;
521 #ifdef SECONDARY_INPUT_RELOAD_CLASS
523 class = SECONDARY_INPUT_RELOAD_CLASS (reload_class, reload_mode, x);
525 #ifdef SECONDARY_OUTPUT_RELOAD_CLASS
527 class = SECONDARY_OUTPUT_RELOAD_CLASS (reload_class, reload_mode, x);
529 if (class != NO_REGS)
531 enum insn_code icode = (in_p ? reload_in_optab[(int) reload_mode]
532 : reload_out_optab[(int) reload_mode]);
534 if (icode != CODE_FOR_nothing
535 && insn_data[(int) icode].operand[in_p].predicate
536 && ! insn_data[(int) icode].operand[in_p].predicate (x, reload_mode))
537 icode = CODE_FOR_nothing;
538 else if (icode != CODE_FOR_nothing)
540 const char *insn_constraint, *scratch_constraint;
541 char insn_letter, scratch_letter;
542 enum reg_class insn_class, scratch_class;
544 gcc_assert (insn_data[(int) icode].n_operands == 3);
545 insn_constraint = insn_data[(int) icode].operand[!in_p].constraint;
546 if (!*insn_constraint)
547 insn_class = ALL_REGS;
552 gcc_assert (*insn_constraint == '=');
555 insn_letter = *insn_constraint;
557 = (insn_letter == 'r' ? GENERAL_REGS
558 : REG_CLASS_FROM_CONSTRAINT ((unsigned char) insn_letter,
560 gcc_assert (insn_class != NO_REGS);
563 scratch_constraint = insn_data[(int) icode].operand[2].constraint;
564 /* The scratch register's constraint must start with "=&",
565 except for an input reload, where only "=" is necessary,
566 and where it might be beneficial to re-use registers from
568 gcc_assert (scratch_constraint[0] == '='
569 && (in_p || scratch_constraint[1] == '&'));
570 scratch_constraint++;
571 if (*scratch_constraint == '&')
572 scratch_constraint++;
573 scratch_letter = *scratch_constraint;
575 = (scratch_letter == 'r' ? GENERAL_REGS
576 : REG_CLASS_FROM_CONSTRAINT ((unsigned char) scratch_letter,
577 scratch_constraint));
579 if (reg_class_subset_p (reload_class, insn_class))
581 gcc_assert (scratch_class == class);
588 if (class == NO_REGS)
591 sri->t_icode = icode;
597 /* If STRICT_ALIGNMENT is true we use the container type for accessing
598 volatile bitfields. This is generally the preferred behavior for memory
599 mapped peripherals on RISC architectures.
600 If STRICT_ALIGNMENT is false we use the narrowest type possible. This
601 is typically used to avoid spurious page faults and extra memory accesses
602 due to unaligned accesses on CISC architectures. */
605 default_narrow_bitfield (void)
607 return !STRICT_ALIGNMENT;
610 /* By default, if flag_pic is true, then neither local nor global relocs
611 should be placed in readonly memory. */
614 default_reloc_rw_mask (void)
616 return flag_pic ? 3 : 0;
620 default_builtin_vector_alignment_reachable (tree type, bool is_packed)
625 /* Assuming that types whose size is > pointer-size are not guaranteed to be
626 naturally aligned. */
627 if (tree_int_cst_compare (TYPE_SIZE (type), bitsize_int (POINTER_SIZE)) > 0)
630 /* Assuming that types whose size is <= pointer-size
631 are naturally aligned. */
635 #include "gt-targhooks.h"