2007-12-17 Vladimir Makarov <vmakarov@redhat.com>
[official-gcc.git] / gcc / targhooks.c
blobb4469403c53980b6c50d25fa4c3f26ca9f417cea
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 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 "tm.h"
53 #include "machmode.h"
54 #include "rtl.h"
55 #include "tree.h"
56 #include "expr.h"
57 #include "output.h"
58 #include "toplev.h"
59 #include "function.h"
60 #include "target.h"
61 #include "tm_p.h"
62 #include "target-def.h"
63 #include "ggc.h"
64 #include "hard-reg-set.h"
65 #include "reload.h"
66 #include "optabs.h"
67 #include "recog.h"
70 void
71 default_external_libcall (rtx fun ATTRIBUTE_UNUSED)
73 #ifdef ASM_OUTPUT_EXTERNAL_LIBCALL
74 ASM_OUTPUT_EXTERNAL_LIBCALL(asm_out_file, fun);
75 #endif
78 enum machine_mode
79 default_cc_modes_compatible (enum machine_mode m1, enum machine_mode m2)
81 if (m1 == m2)
82 return m1;
83 return VOIDmode;
86 bool
87 default_return_in_memory (const_tree type,
88 const_tree fntype ATTRIBUTE_UNUSED)
90 #ifndef RETURN_IN_MEMORY
91 return (TYPE_MODE (type) == BLKmode);
92 #else
93 return RETURN_IN_MEMORY (type);
94 #endif
97 rtx
98 default_expand_builtin_saveregs (void)
100 error ("__builtin_saveregs not supported by this target");
101 return const0_rtx;
104 void
105 default_setup_incoming_varargs (CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
106 enum machine_mode mode ATTRIBUTE_UNUSED,
107 tree type ATTRIBUTE_UNUSED,
108 int *pretend_arg_size ATTRIBUTE_UNUSED,
109 int second_time ATTRIBUTE_UNUSED)
113 /* The default implementation of TARGET_BUILTIN_SETJMP_FRAME_VALUE. */
116 default_builtin_setjmp_frame_value (void)
118 return virtual_stack_vars_rtx;
121 /* Generic hook that takes a CUMULATIVE_ARGS pointer and returns false. */
123 bool
124 hook_bool_CUMULATIVE_ARGS_false (CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED)
126 return false;
129 bool
130 default_pretend_outgoing_varargs_named (CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED)
132 return (targetm.calls.setup_incoming_varargs
133 != default_setup_incoming_varargs);
136 enum machine_mode
137 default_eh_return_filter_mode (void)
139 return word_mode;
142 enum machine_mode
143 default_libgcc_cmp_return_mode (void)
145 return word_mode;
148 enum machine_mode
149 default_libgcc_shift_count_mode (void)
151 return word_mode;
154 /* The default implementation of TARGET_SHIFT_TRUNCATION_MASK. */
156 unsigned HOST_WIDE_INT
157 default_shift_truncation_mask (enum machine_mode mode)
159 return SHIFT_COUNT_TRUNCATED ? GET_MODE_BITSIZE (mode) - 1 : 0;
162 /* The default implementation of TARGET_MIN_DIVISIONS_FOR_RECIP_MUL. */
164 unsigned int
165 default_min_divisions_for_recip_mul (enum machine_mode mode ATTRIBUTE_UNUSED)
167 return have_insn_for (DIV, mode) ? 3 : 2;
170 /* The default implementation of TARGET_MODE_REP_EXTENDED. */
173 default_mode_rep_extended (enum machine_mode mode ATTRIBUTE_UNUSED,
174 enum machine_mode mode_rep ATTRIBUTE_UNUSED)
176 return UNKNOWN;
179 /* Generic hook that takes a CUMULATIVE_ARGS pointer and returns true. */
181 bool
182 hook_bool_CUMULATIVE_ARGS_true (CUMULATIVE_ARGS * a ATTRIBUTE_UNUSED)
184 return true;
187 /* Return machine mode for non-standard suffix
188 or VOIDmode if non-standard suffixes are unsupported. */
189 enum machine_mode
190 default_mode_for_suffix (char suffix ATTRIBUTE_UNUSED)
192 return VOIDmode;
195 /* The generic C++ ABI specifies this is a 64-bit value. */
196 tree
197 default_cxx_guard_type (void)
199 return long_long_integer_type_node;
203 /* Returns the size of the cookie to use when allocating an array
204 whose elements have the indicated TYPE. Assumes that it is already
205 known that a cookie is needed. */
207 tree
208 default_cxx_get_cookie_size (tree type)
210 tree cookie_size;
212 /* We need to allocate an additional max (sizeof (size_t), alignof
213 (true_type)) bytes. */
214 tree sizetype_size;
215 tree type_align;
217 sizetype_size = size_in_bytes (sizetype);
218 type_align = size_int (TYPE_ALIGN_UNIT (type));
219 if (INT_CST_LT_UNSIGNED (type_align, sizetype_size))
220 cookie_size = sizetype_size;
221 else
222 cookie_size = type_align;
224 return cookie_size;
227 /* Return true if a parameter must be passed by reference. This version
228 of the TARGET_PASS_BY_REFERENCE hook uses just MUST_PASS_IN_STACK. */
230 bool
231 hook_pass_by_reference_must_pass_in_stack (CUMULATIVE_ARGS *c ATTRIBUTE_UNUSED,
232 enum machine_mode mode ATTRIBUTE_UNUSED, const_tree type ATTRIBUTE_UNUSED,
233 bool named_arg ATTRIBUTE_UNUSED)
235 return targetm.calls.must_pass_in_stack (mode, type);
238 /* Return true if a parameter follows callee copies conventions. This
239 version of the hook is true for all named arguments. */
241 bool
242 hook_callee_copies_named (CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
243 enum machine_mode mode ATTRIBUTE_UNUSED,
244 const_tree type ATTRIBUTE_UNUSED, bool named)
246 return named;
249 /* Emit any directives required to unwind this instruction. */
251 void
252 default_unwind_emit (FILE * stream ATTRIBUTE_UNUSED,
253 rtx insn ATTRIBUTE_UNUSED)
255 /* Should never happen. */
256 gcc_unreachable ();
259 /* True if MODE is valid for the target. By "valid", we mean able to
260 be manipulated in non-trivial ways. In particular, this means all
261 the arithmetic is supported.
263 By default we guess this means that any C type is supported. If
264 we can't map the mode back to a type that would be available in C,
265 then reject it. Special case, here, is the double-word arithmetic
266 supported by optabs.c. */
268 bool
269 default_scalar_mode_supported_p (enum machine_mode mode)
271 int precision = GET_MODE_PRECISION (mode);
273 switch (GET_MODE_CLASS (mode))
275 case MODE_PARTIAL_INT:
276 case MODE_INT:
277 if (precision == CHAR_TYPE_SIZE)
278 return true;
279 if (precision == SHORT_TYPE_SIZE)
280 return true;
281 if (precision == INT_TYPE_SIZE)
282 return true;
283 if (precision == LONG_TYPE_SIZE)
284 return true;
285 if (precision == LONG_LONG_TYPE_SIZE)
286 return true;
287 if (precision == 2 * BITS_PER_WORD)
288 return true;
289 return false;
291 case MODE_FLOAT:
292 if (precision == FLOAT_TYPE_SIZE)
293 return true;
294 if (precision == DOUBLE_TYPE_SIZE)
295 return true;
296 if (precision == LONG_DOUBLE_TYPE_SIZE)
297 return true;
298 return false;
300 case MODE_DECIMAL_FLOAT:
301 case MODE_FRACT:
302 case MODE_UFRACT:
303 case MODE_ACCUM:
304 case MODE_UACCUM:
305 return false;
307 default:
308 gcc_unreachable ();
312 /* True if the target supports decimal floating point. */
314 bool
315 default_decimal_float_supported_p (void)
317 return ENABLE_DECIMAL_FLOAT;
320 /* True if the target supports fixed-point arithmetic. */
322 bool
323 default_fixed_point_supported_p (void)
325 return ENABLE_FIXED_POINT;
328 /* NULL if INSN insn is valid within a low-overhead loop, otherwise returns
329 an error message.
331 This function checks whether a given INSN is valid within a low-overhead
332 loop. If INSN is invalid it returns the reason for that, otherwise it
333 returns NULL. A called function may clobber any special registers required
334 for low-overhead looping. Additionally, some targets (eg, PPC) use the count
335 register for branch on table instructions. We reject the doloop pattern in
336 these cases. */
338 const char *
339 default_invalid_within_doloop (const_rtx insn)
341 if (CALL_P (insn))
342 return "Function call in loop.";
344 if (JUMP_P (insn)
345 && (GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC
346 || GET_CODE (PATTERN (insn)) == ADDR_VEC))
347 return "Computed branch in the loop.";
349 return NULL;
352 /* Mapping of builtin functions to vectorized variants. */
354 tree
355 default_builtin_vectorized_function (enum built_in_function fn ATTRIBUTE_UNUSED,
356 tree type_out ATTRIBUTE_UNUSED,
357 tree type_in ATTRIBUTE_UNUSED)
359 return NULL_TREE;
362 /* Vectorized conversion. */
364 tree
365 default_builtin_vectorized_conversion (enum tree_code code ATTRIBUTE_UNUSED,
366 tree type ATTRIBUTE_UNUSED)
368 return NULL_TREE;
371 /* Reciprocal. */
373 tree
374 default_builtin_reciprocal (enum built_in_function fn ATTRIBUTE_UNUSED,
375 bool md_fn ATTRIBUTE_UNUSED,
376 bool sqrt ATTRIBUTE_UNUSED)
378 return NULL_TREE;
381 bool
382 hook_bool_CUMULATIVE_ARGS_mode_tree_bool_false (
383 CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
384 enum machine_mode mode ATTRIBUTE_UNUSED,
385 const_tree type ATTRIBUTE_UNUSED, bool named ATTRIBUTE_UNUSED)
387 return false;
390 bool
391 hook_bool_CUMULATIVE_ARGS_mode_tree_bool_true (
392 CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
393 enum machine_mode mode ATTRIBUTE_UNUSED,
394 const_tree type ATTRIBUTE_UNUSED, bool named ATTRIBUTE_UNUSED)
396 return true;
400 hook_int_CUMULATIVE_ARGS_mode_tree_bool_0 (
401 CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
402 enum machine_mode mode ATTRIBUTE_UNUSED,
403 tree type ATTRIBUTE_UNUSED, bool named ATTRIBUTE_UNUSED)
405 return 0;
408 void
409 hook_void_bitmap (bitmap regs ATTRIBUTE_UNUSED)
413 const char *
414 hook_invalid_arg_for_unprototyped_fn (
415 const_tree typelist ATTRIBUTE_UNUSED,
416 const_tree funcdecl ATTRIBUTE_UNUSED,
417 const_tree val ATTRIBUTE_UNUSED)
419 return NULL;
422 /* Initialize the stack protection decls. */
424 /* Stack protection related decls living in libgcc. */
425 static GTY(()) tree stack_chk_guard_decl;
427 tree
428 default_stack_protect_guard (void)
430 tree t = stack_chk_guard_decl;
432 if (t == NULL)
434 t = build_decl (VAR_DECL, get_identifier ("__stack_chk_guard"),
435 ptr_type_node);
436 TREE_STATIC (t) = 1;
437 TREE_PUBLIC (t) = 1;
438 DECL_EXTERNAL (t) = 1;
439 TREE_USED (t) = 1;
440 TREE_THIS_VOLATILE (t) = 1;
441 DECL_ARTIFICIAL (t) = 1;
442 DECL_IGNORED_P (t) = 1;
444 stack_chk_guard_decl = t;
447 return t;
450 static GTY(()) tree stack_chk_fail_decl;
452 tree
453 default_external_stack_protect_fail (void)
455 tree t = stack_chk_fail_decl;
457 if (t == NULL_TREE)
459 t = build_function_type_list (void_type_node, NULL_TREE);
460 t = build_decl (FUNCTION_DECL, get_identifier ("__stack_chk_fail"), t);
461 TREE_STATIC (t) = 1;
462 TREE_PUBLIC (t) = 1;
463 DECL_EXTERNAL (t) = 1;
464 TREE_USED (t) = 1;
465 TREE_THIS_VOLATILE (t) = 1;
466 TREE_NOTHROW (t) = 1;
467 DECL_ARTIFICIAL (t) = 1;
468 DECL_IGNORED_P (t) = 1;
469 DECL_VISIBILITY (t) = VISIBILITY_DEFAULT;
470 DECL_VISIBILITY_SPECIFIED (t) = 1;
472 stack_chk_fail_decl = t;
475 return build_call_expr (t, 0);
478 tree
479 default_hidden_stack_protect_fail (void)
481 #ifndef HAVE_GAS_HIDDEN
482 return default_external_stack_protect_fail ();
483 #else
484 tree t = stack_chk_fail_decl;
486 if (!flag_pic)
487 return default_external_stack_protect_fail ();
489 if (t == NULL_TREE)
491 t = build_function_type_list (void_type_node, NULL_TREE);
492 t = build_decl (FUNCTION_DECL,
493 get_identifier ("__stack_chk_fail_local"), t);
494 TREE_STATIC (t) = 1;
495 TREE_PUBLIC (t) = 1;
496 DECL_EXTERNAL (t) = 1;
497 TREE_USED (t) = 1;
498 TREE_THIS_VOLATILE (t) = 1;
499 TREE_NOTHROW (t) = 1;
500 DECL_ARTIFICIAL (t) = 1;
501 DECL_IGNORED_P (t) = 1;
502 DECL_VISIBILITY_SPECIFIED (t) = 1;
503 DECL_VISIBILITY (t) = VISIBILITY_HIDDEN;
505 stack_chk_fail_decl = t;
508 return build_call_expr (t, 0);
509 #endif
512 bool
513 hook_bool_const_rtx_commutative_p (const_rtx x,
514 int outer_code ATTRIBUTE_UNUSED)
516 return COMMUTATIVE_P (x);
520 default_function_value (const_tree ret_type ATTRIBUTE_UNUSED,
521 const_tree fn_decl_or_type,
522 bool outgoing ATTRIBUTE_UNUSED)
524 /* The old interface doesn't handle receiving the function type. */
525 if (fn_decl_or_type
526 && !DECL_P (fn_decl_or_type))
527 fn_decl_or_type = NULL;
529 #ifdef FUNCTION_OUTGOING_VALUE
530 if (outgoing)
531 return FUNCTION_OUTGOING_VALUE (ret_type, fn_decl_or_type);
532 #endif
534 #ifdef FUNCTION_VALUE
535 return FUNCTION_VALUE (ret_type, fn_decl_or_type);
536 #else
537 return NULL_RTX;
538 #endif
542 default_internal_arg_pointer (void)
544 /* If the reg that the virtual arg pointer will be translated into is
545 not a fixed reg or is the stack pointer, make a copy of the virtual
546 arg pointer, and address parms via the copy. The frame pointer is
547 considered fixed even though it is not marked as such. */
548 if ((ARG_POINTER_REGNUM == STACK_POINTER_REGNUM
549 || ! (fixed_regs[ARG_POINTER_REGNUM]
550 || ARG_POINTER_REGNUM == FRAME_POINTER_REGNUM)))
551 return copy_to_reg (virtual_incoming_args_rtx);
552 else
553 return virtual_incoming_args_rtx;
556 enum reg_class
557 default_secondary_reload (bool in_p ATTRIBUTE_UNUSED, rtx x ATTRIBUTE_UNUSED,
558 enum reg_class reload_class ATTRIBUTE_UNUSED,
559 enum machine_mode reload_mode ATTRIBUTE_UNUSED,
560 secondary_reload_info *sri)
562 enum reg_class class = NO_REGS;
564 if (sri->prev_sri && sri->prev_sri->t_icode != CODE_FOR_nothing)
566 sri->icode = sri->prev_sri->t_icode;
567 return NO_REGS;
569 #ifdef SECONDARY_INPUT_RELOAD_CLASS
570 if (in_p)
571 class = SECONDARY_INPUT_RELOAD_CLASS (reload_class, reload_mode, x);
572 #endif
573 #ifdef SECONDARY_OUTPUT_RELOAD_CLASS
574 if (! in_p)
575 class = SECONDARY_OUTPUT_RELOAD_CLASS (reload_class, reload_mode, x);
576 #endif
577 if (class != NO_REGS)
579 enum insn_code icode = (in_p ? reload_in_optab[(int) reload_mode]
580 : reload_out_optab[(int) reload_mode]);
582 if (icode != CODE_FOR_nothing
583 && insn_data[(int) icode].operand[in_p].predicate
584 && ! insn_data[(int) icode].operand[in_p].predicate (x, reload_mode))
585 icode = CODE_FOR_nothing;
586 else if (icode != CODE_FOR_nothing)
588 const char *insn_constraint, *scratch_constraint;
589 char insn_letter, scratch_letter;
590 enum reg_class insn_class, scratch_class;
592 gcc_assert (insn_data[(int) icode].n_operands == 3);
593 insn_constraint = insn_data[(int) icode].operand[!in_p].constraint;
594 if (!*insn_constraint)
595 insn_class = ALL_REGS;
596 else
598 if (in_p)
600 gcc_assert (*insn_constraint == '=');
601 insn_constraint++;
603 insn_letter = *insn_constraint;
604 insn_class
605 = (insn_letter == 'r' ? GENERAL_REGS
606 : REG_CLASS_FROM_CONSTRAINT ((unsigned char) insn_letter,
607 insn_constraint));
608 gcc_assert (insn_class != NO_REGS);
611 scratch_constraint = insn_data[(int) icode].operand[2].constraint;
612 /* The scratch register's constraint must start with "=&",
613 except for an input reload, where only "=" is necessary,
614 and where it might be beneficial to re-use registers from
615 the input. */
616 gcc_assert (scratch_constraint[0] == '='
617 && (in_p || scratch_constraint[1] == '&'));
618 scratch_constraint++;
619 if (*scratch_constraint == '&')
620 scratch_constraint++;
621 scratch_letter = *scratch_constraint;
622 scratch_class
623 = (scratch_letter == 'r' ? GENERAL_REGS
624 : REG_CLASS_FROM_CONSTRAINT ((unsigned char) scratch_letter,
625 scratch_constraint));
627 if (reg_class_subset_p (reload_class, insn_class))
629 gcc_assert (scratch_class == class);
630 class = NO_REGS;
632 else
633 class = insn_class;
636 if (class == NO_REGS)
637 sri->icode = icode;
638 else
639 sri->t_icode = icode;
641 return class;
644 bool
645 default_handle_c_option (size_t code ATTRIBUTE_UNUSED,
646 const char *arg ATTRIBUTE_UNUSED,
647 int value ATTRIBUTE_UNUSED)
649 return false;
652 /* By default, if flag_pic is true, then neither local nor global relocs
653 should be placed in readonly memory. */
656 default_reloc_rw_mask (void)
658 return flag_pic ? 3 : 0;
661 /* By default, do no modification. */
662 tree default_mangle_decl_assembler_name (tree decl ATTRIBUTE_UNUSED,
663 tree id)
665 return id;
668 bool
669 default_builtin_vector_alignment_reachable (const_tree type, bool is_packed)
671 if (is_packed)
672 return false;
674 /* Assuming that types whose size is > pointer-size are not guaranteed to be
675 naturally aligned. */
676 if (tree_int_cst_compare (TYPE_SIZE (type), bitsize_int (POINTER_SIZE)) > 0)
677 return false;
679 /* Assuming that types whose size is <= pointer-size
680 are naturally aligned. */
681 return true;
684 #include "gt-targhooks.h"