1 /* Default target hook functions.
2 Copyright (C) 2003, 2004, 2005 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);
99 default_expand_builtin_saveregs (void)
101 error ("__builtin_saveregs not supported by this target");
106 default_setup_incoming_varargs (CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
107 enum machine_mode mode ATTRIBUTE_UNUSED,
108 tree type ATTRIBUTE_UNUSED,
109 int *pretend_arg_size ATTRIBUTE_UNUSED,
110 int second_time ATTRIBUTE_UNUSED)
114 /* The default implementation of TARGET_BUILTIN_SETJMP_FRAME_VALUE. */
117 default_builtin_setjmp_frame_value (void)
119 return virtual_stack_vars_rtx;
122 /* Generic hook that takes a CUMULATIVE_ARGS pointer and returns false. */
125 hook_bool_CUMULATIVE_ARGS_false (CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED)
131 default_pretend_outgoing_varargs_named (CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED)
133 return (targetm.calls.setup_incoming_varargs
134 != default_setup_incoming_varargs);
138 default_eh_return_filter_mode (void)
143 /* The default implementation of TARGET_SHIFT_TRUNCATION_MASK. */
145 unsigned HOST_WIDE_INT
146 default_shift_truncation_mask (enum machine_mode mode)
148 return SHIFT_COUNT_TRUNCATED ? GET_MODE_BITSIZE (mode) - 1 : 0;
151 /* The default implementation of TARGET_MIN_DIVISIONS_FOR_RECIP_MUL. */
154 default_min_divisions_for_recip_mul (enum machine_mode mode ATTRIBUTE_UNUSED)
156 return have_insn_for (DIV, mode) ? 3 : 2;
159 /* Generic hook that takes a CUMULATIVE_ARGS pointer and returns true. */
162 hook_bool_CUMULATIVE_ARGS_true (CUMULATIVE_ARGS * a ATTRIBUTE_UNUSED)
168 /* The generic C++ ABI specifies this is a 64-bit value. */
170 default_cxx_guard_type (void)
172 return long_long_integer_type_node;
176 /* Returns the size of the cookie to use when allocating an array
177 whose elements have the indicated TYPE. Assumes that it is already
178 known that a cookie is needed. */
181 default_cxx_get_cookie_size (tree type)
185 /* We need to allocate an additional max (sizeof (size_t), alignof
186 (true_type)) bytes. */
190 sizetype_size = size_in_bytes (sizetype);
191 type_align = size_int (TYPE_ALIGN_UNIT (type));
192 if (INT_CST_LT_UNSIGNED (type_align, sizetype_size))
193 cookie_size = sizetype_size;
195 cookie_size = type_align;
200 /* Return true if a parameter must be passed by reference. This version
201 of the TARGET_PASS_BY_REFERENCE hook uses just MUST_PASS_IN_STACK. */
204 hook_pass_by_reference_must_pass_in_stack (CUMULATIVE_ARGS *c ATTRIBUTE_UNUSED,
205 enum machine_mode mode ATTRIBUTE_UNUSED, tree type ATTRIBUTE_UNUSED,
206 bool named_arg ATTRIBUTE_UNUSED)
208 return targetm.calls.must_pass_in_stack (mode, type);
211 /* Return true if a parameter follows callee copies conventions. This
212 version of the hook is true for all named arguments. */
215 hook_callee_copies_named (CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
216 enum machine_mode mode ATTRIBUTE_UNUSED,
217 tree type ATTRIBUTE_UNUSED, bool named)
222 /* Emit any directives required to unwind this instruction. */
225 default_unwind_emit (FILE * stream ATTRIBUTE_UNUSED,
226 rtx insn ATTRIBUTE_UNUSED)
228 /* Should never happen. */
232 /* True if MODE is valid for the target. By "valid", we mean able to
233 be manipulated in non-trivial ways. In particular, this means all
234 the arithmetic is supported.
236 By default we guess this means that any C type is supported. If
237 we can't map the mode back to a type that would be available in C,
238 then reject it. Special case, here, is the double-word arithmetic
239 supported by optabs.c. */
242 default_scalar_mode_supported_p (enum machine_mode mode)
244 int precision = GET_MODE_PRECISION (mode);
246 switch (GET_MODE_CLASS (mode))
248 case MODE_PARTIAL_INT:
250 if (precision == CHAR_TYPE_SIZE)
252 if (precision == SHORT_TYPE_SIZE)
254 if (precision == INT_TYPE_SIZE)
256 if (precision == LONG_TYPE_SIZE)
258 if (precision == LONG_LONG_TYPE_SIZE)
260 if (precision == 2 * BITS_PER_WORD)
265 if (precision == FLOAT_TYPE_SIZE)
267 if (precision == DOUBLE_TYPE_SIZE)
269 if (precision == LONG_DOUBLE_TYPE_SIZE)
273 case MODE_DECIMAL_FLOAT:
281 /* True if the target supports decimal floating point. */
284 default_decimal_float_supported_p (void)
286 return ENABLE_DECIMAL_FLOAT;
289 /* NULL if INSN insn is valid within a low-overhead loop, otherwise returns
292 This function checks whether a given INSN is valid within a low-overhead
293 loop. If INSN is invalid it returns the reason for that, otherwise it
294 returns NULL. A called function may clobber any special registers required
295 for low-overhead looping. Additionally, some targets (eg, PPC) use the count
296 register for branch on table instructions. We reject the doloop pattern in
300 default_invalid_within_doloop (rtx insn)
303 return "Function call in loop.";
306 && (GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC
307 || GET_CODE (PATTERN (insn)) == ADDR_VEC))
308 return "Computed branch in the loop.";
314 hook_bool_CUMULATIVE_ARGS_mode_tree_bool_false (
315 CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
316 enum machine_mode mode ATTRIBUTE_UNUSED,
317 tree type ATTRIBUTE_UNUSED, bool named ATTRIBUTE_UNUSED)
323 hook_bool_CUMULATIVE_ARGS_mode_tree_bool_true (
324 CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
325 enum machine_mode mode ATTRIBUTE_UNUSED,
326 tree type ATTRIBUTE_UNUSED, bool named ATTRIBUTE_UNUSED)
332 hook_int_CUMULATIVE_ARGS_mode_tree_bool_0 (
333 CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED,
334 enum machine_mode mode ATTRIBUTE_UNUSED,
335 tree type ATTRIBUTE_UNUSED, bool named ATTRIBUTE_UNUSED)
341 hook_invalid_arg_for_unprototyped_fn (
342 tree typelist ATTRIBUTE_UNUSED,
343 tree funcdecl ATTRIBUTE_UNUSED,
344 tree val ATTRIBUTE_UNUSED)
349 /* Initialize the stack protection decls. */
351 /* Stack protection related decls living in libgcc. */
352 static GTY(()) tree stack_chk_guard_decl;
355 default_stack_protect_guard (void)
357 tree t = stack_chk_guard_decl;
361 t = build_decl (VAR_DECL, get_identifier ("__stack_chk_guard"),
365 DECL_EXTERNAL (t) = 1;
367 TREE_THIS_VOLATILE (t) = 1;
368 DECL_ARTIFICIAL (t) = 1;
369 DECL_IGNORED_P (t) = 1;
371 stack_chk_guard_decl = t;
377 static GTY(()) tree stack_chk_fail_decl;
380 default_external_stack_protect_fail (void)
382 tree t = stack_chk_fail_decl;
386 t = build_function_type_list (void_type_node, NULL_TREE);
387 t = build_decl (FUNCTION_DECL, get_identifier ("__stack_chk_fail"), t);
390 DECL_EXTERNAL (t) = 1;
392 TREE_THIS_VOLATILE (t) = 1;
393 TREE_NOTHROW (t) = 1;
394 DECL_ARTIFICIAL (t) = 1;
395 DECL_IGNORED_P (t) = 1;
397 stack_chk_fail_decl = t;
400 return build_function_call_expr (t, NULL_TREE);
404 default_hidden_stack_protect_fail (void)
406 #ifndef HAVE_GAS_HIDDEN
407 return default_external_stack_protect_fail ();
409 tree t = stack_chk_fail_decl;
412 return default_external_stack_protect_fail ();
416 t = build_function_type_list (void_type_node, NULL_TREE);
417 t = build_decl (FUNCTION_DECL,
418 get_identifier ("__stack_chk_fail_local"), t);
421 DECL_EXTERNAL (t) = 1;
423 TREE_THIS_VOLATILE (t) = 1;
424 TREE_NOTHROW (t) = 1;
425 DECL_ARTIFICIAL (t) = 1;
426 DECL_IGNORED_P (t) = 1;
427 DECL_VISIBILITY_SPECIFIED (t) = 1;
428 DECL_VISIBILITY (t) = VISIBILITY_HIDDEN;
430 stack_chk_fail_decl = t;
433 return build_function_call_expr (t, NULL_TREE);
438 hook_bool_rtx_commutative_p (rtx x, int outer_code ATTRIBUTE_UNUSED)
440 return COMMUTATIVE_P (x);
444 default_function_value (tree ret_type ATTRIBUTE_UNUSED,
445 tree fn_decl_or_type,
446 bool outgoing ATTRIBUTE_UNUSED)
448 /* The old interface doesn't handle receiving the function type. */
450 && !DECL_P (fn_decl_or_type))
451 fn_decl_or_type = NULL;
453 #ifdef FUNCTION_OUTGOING_VALUE
455 return FUNCTION_OUTGOING_VALUE (ret_type, fn_decl_or_type);
458 #ifdef FUNCTION_VALUE
459 return FUNCTION_VALUE (ret_type, fn_decl_or_type);
466 default_internal_arg_pointer (void)
468 /* If the reg that the virtual arg pointer will be translated into is
469 not a fixed reg or is the stack pointer, make a copy of the virtual
470 arg pointer, and address parms via the copy. The frame pointer is
471 considered fixed even though it is not marked as such. */
472 if ((ARG_POINTER_REGNUM == STACK_POINTER_REGNUM
473 || ! (fixed_regs[ARG_POINTER_REGNUM]
474 || ARG_POINTER_REGNUM == FRAME_POINTER_REGNUM)))
475 return copy_to_reg (virtual_incoming_args_rtx);
477 return virtual_incoming_args_rtx;
481 default_secondary_reload (bool in_p ATTRIBUTE_UNUSED, rtx x ATTRIBUTE_UNUSED,
482 enum reg_class reload_class ATTRIBUTE_UNUSED,
483 enum machine_mode reload_mode ATTRIBUTE_UNUSED,
484 secondary_reload_info *sri)
486 enum reg_class class = NO_REGS;
488 if (sri->prev_sri && sri->prev_sri->t_icode != CODE_FOR_nothing)
490 sri->icode = sri->prev_sri->t_icode;
493 #ifdef SECONDARY_INPUT_RELOAD_CLASS
495 class = SECONDARY_INPUT_RELOAD_CLASS (reload_class, reload_mode, x);
497 #ifdef SECONDARY_OUTPUT_RELOAD_CLASS
499 class = SECONDARY_OUTPUT_RELOAD_CLASS (reload_class, reload_mode, x);
501 if (class != NO_REGS)
503 enum insn_code icode = (in_p ? reload_in_optab[(int) reload_mode]
504 : reload_out_optab[(int) reload_mode]);
506 if (icode != CODE_FOR_nothing
507 && insn_data[(int) icode].operand[in_p].predicate
508 && ! insn_data[(int) icode].operand[in_p].predicate (x, reload_mode))
509 icode = CODE_FOR_nothing;
510 else if (icode != CODE_FOR_nothing)
512 const char *insn_constraint, *scratch_constraint;
513 char insn_letter, scratch_letter;
514 enum reg_class insn_class, scratch_class;
516 gcc_assert (insn_data[(int) icode].n_operands == 3);
517 insn_constraint = insn_data[(int) icode].operand[!in_p].constraint;
518 if (!*insn_constraint)
519 insn_class = ALL_REGS;
524 gcc_assert (*insn_constraint == '=');
527 insn_letter = *insn_constraint;
529 = (insn_letter == 'r' ? GENERAL_REGS
530 : REG_CLASS_FROM_CONSTRAINT ((unsigned char) insn_letter,
532 gcc_assert (insn_class != NO_REGS);
535 scratch_constraint = insn_data[(int) icode].operand[2].constraint;
536 /* The scratch register's constraint must start with "=&",
537 except for an input reload, where only "=" is necessary,
538 and where it might be beneficial to re-use registers from
540 gcc_assert (scratch_constraint[0] == '='
541 && (in_p || scratch_constraint[1] == '&'));
542 scratch_constraint++;
543 if (*scratch_constraint == '&')
544 scratch_constraint++;
545 scratch_letter = *scratch_constraint;
547 = (scratch_letter == 'r' ? GENERAL_REGS
548 : REG_CLASS_FROM_CONSTRAINT ((unsigned char) scratch_letter,
549 scratch_constraint));
551 if (reg_class_subset_p (reload_class, insn_class))
553 gcc_assert (scratch_class == class);
560 if (class == NO_REGS)
563 sri->t_icode = icode;
568 #include "gt-targhooks.h"