1 /* Data structure definitions for a generic GCC target.
2 Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007
3 Free Software Foundation, Inc.
5 This program is free software; you can redistribute it and/or modify it
6 under the terms of the GNU General Public License as published by the
7 Free Software Foundation; either version 3, or (at your option) any
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with this program; see the file COPYING3. If not see
17 <http://www.gnu.org/licenses/>.
19 In other words, you are welcome to use, share and improve this program.
20 You are forbidden to forbid anyone else to use, share and improve
21 what you give them. Help stamp out software-hoarding! */
24 /* This file contains a data structure that describes a GCC target.
25 At present it is incomplete, but in future it should grow to
26 contain most or all target machine and target O/S specific
29 This structure has its initializer declared in target-def.h in the
30 form of large macro TARGET_INITIALIZER that expands to many smaller
33 The smaller macros each initialize one component of the structure,
34 and each has a default. Each target should have a file that
35 includes target.h and target-def.h, and overrides any inappropriate
36 defaults by undefining the relevant macro and defining a suitable
37 replacement. That file should then contain the definition of
40 struct gcc_target targetm = TARGET_INITIALIZER;
42 Doing things this way allows us to bring together everything that
43 defines a GCC target. By supplying a default that is appropriate
44 to most targets, we can easily add new items without needing to
45 edit dozens of target configuration files. It should also allow us
46 to gradually reduce the amount of conditional compilation that is
47 scattered throughout GCC. */
53 #include "insn-modes.h"
55 /* Types used by the record_gcc_switches() target function. */
58 SWITCH_TYPE_PASSED, /* A switch passed on the command line. */
59 SWITCH_TYPE_ENABLED, /* An option that is currently enabled. */
60 SWITCH_TYPE_DESCRIPTIVE, /* Descriptive text, not a switch or option. */
61 SWITCH_TYPE_LINE_START, /* Please emit any necessary text at the start of a line. */
62 SWITCH_TYPE_LINE_END /* Please emit a line terminator. */
66 typedef int (* print_switch_fn_type) (print_switch_type, const char *);
68 /* An example implementation for ELF targets. Defined in varasm.c */
69 extern int elf_record_gcc_switches (print_switch_type type, const char *);
74 /* The struct used by the secondary_reload target hook. */
75 typedef struct secondary_reload_info
77 /* icode is actually an enum insn_code, but we don't want to force every
78 file that includes target.h to include optabs.h . */
80 int extra_cost; /* Cost for using (a) scratch register(s) to be taken
81 into account by copy_cost. */
82 /* The next two members are for the use of the backward
83 compatibility hook. */
84 struct secondary_reload_info *prev_sri;
85 int t_icode; /* Actually an enum insn_code - see above. */
86 } secondary_reload_info;
88 /* This is defined in sched-int.h . */
91 /* This is defined in ddg.h . */
96 /* Functions that output assembler for the target. */
99 /* Opening and closing parentheses for asm expression grouping. */
100 const char *open_paren, *close_paren;
102 /* Assembler instructions for creating various kinds of integer object. */
110 } aligned_op, unaligned_op;
112 /* Try to output the assembler code for an integer object whose
113 value is given by X. SIZE is the size of the object in bytes and
114 ALIGNED_P indicates whether it is aligned. Return true if
115 successful. Only handles cases for which BYTE_OP, ALIGNED_OP
116 and UNALIGNED_OP are NULL. */
117 bool (* integer) (rtx x, unsigned int size, int aligned_p);
119 /* Output code that will globalize a label. */
120 void (* globalize_label) (FILE *, const char *);
122 /* Output code that will globalize a declaration. */
123 void (* globalize_decl_name) (FILE *, tree);
125 /* Output code that will emit a label for unwind info, if this
126 target requires such labels. Second argument is the decl the
127 unwind info is associated with, third is a boolean: true if
128 this is for exception handling, fourth is a boolean: true if
129 this is only a placeholder for an omitted FDE. */
130 void (* unwind_label) (FILE *, tree, int, int);
132 /* Output code that will emit a label to divide up the exception
134 void (* except_table_label) (FILE *);
136 /* Emit any directives required to unwind this instruction. */
137 void (* unwind_emit) (FILE *, rtx);
139 /* Output an internal label. */
140 void (* internal_label) (FILE *, const char *, unsigned long);
142 /* Emit a ttype table reference to a typeinfo object. */
143 bool (* ttype) (rtx);
145 /* Emit an assembler directive to set visibility for the symbol
146 associated with the tree decl. */
147 void (* visibility) (tree, int);
149 /* Output the assembler code for entry to a function. */
150 void (* function_prologue) (FILE *, HOST_WIDE_INT);
152 /* Output the assembler code for end of prologue. */
153 void (* function_end_prologue) (FILE *);
155 /* Output the assembler code for start of epilogue. */
156 void (* function_begin_epilogue) (FILE *);
158 /* Output the assembler code for function exit. */
159 void (* function_epilogue) (FILE *, HOST_WIDE_INT);
161 /* Initialize target-specific sections. */
162 void (* init_sections) (void);
164 /* Tell assembler to change to section NAME with attributes FLAGS.
165 If DECL is non-NULL, it is the VAR_DECL or FUNCTION_DECL with
166 which this section is associated. */
167 void (* named_section) (const char *name, unsigned int flags, tree decl);
169 /* Return a mask describing how relocations should be treated when
170 selecting sections. Bit 1 should be set if global relocations
171 should be placed in a read-write section; bit 0 should be set if
172 local relocations should be placed in a read-write section. */
173 int (*reloc_rw_mask) (void);
175 /* Return a section for EXP. It may be a DECL or a constant. RELOC
176 is nonzero if runtime relocations must be applied; bit 1 will be
177 set if the runtime relocations require non-local name resolution.
178 ALIGN is the required alignment of the data. */
179 section *(* select_section) (tree, int, unsigned HOST_WIDE_INT);
181 /* Return a section for X. MODE is X's mode and ALIGN is its
182 alignment in bits. */
183 section *(* select_rtx_section) (enum machine_mode, rtx,
184 unsigned HOST_WIDE_INT);
186 /* Select a unique section name for DECL. RELOC is the same as
187 for SELECT_SECTION. */
188 void (* unique_section) (tree, int);
190 /* Return the readonly data section associated with function DECL. */
191 section *(* function_rodata_section) (tree);
193 /* Output a constructor for a symbol with a given priority. */
194 void (* constructor) (rtx, int);
196 /* Output a destructor for a symbol with a given priority. */
197 void (* destructor) (rtx, int);
199 /* Output the assembler code for a thunk function. THUNK_DECL is the
200 declaration for the thunk function itself, FUNCTION is the decl for
201 the target function. DELTA is an immediate constant offset to be
202 added to THIS. If VCALL_OFFSET is nonzero, the word at
203 *(*this + vcall_offset) should be added to THIS. */
204 void (* output_mi_thunk) (FILE *file, tree thunk_decl,
205 HOST_WIDE_INT delta, HOST_WIDE_INT vcall_offset,
208 /* Determine whether output_mi_thunk would succeed. */
209 /* ??? Ideally, this hook would not exist, and success or failure
210 would be returned from output_mi_thunk directly. But there's
211 too much undo-able setup involved in invoking output_mi_thunk.
212 Could be fixed by making output_mi_thunk emit rtl instead of
213 text to the output file. */
214 bool (* can_output_mi_thunk) (const_tree thunk_decl, HOST_WIDE_INT delta,
215 HOST_WIDE_INT vcall_offset,
216 const_tree function_decl);
218 /* Output any boilerplate text needed at the beginning of a
220 void (*file_start) (void);
222 /* Output any boilerplate text needed at the end of a
224 void (*file_end) (void);
226 /* Output an assembler pseudo-op to declare a library function name
228 void (*external_libcall) (rtx);
230 /* Output an assembler directive to mark decl live. This instructs
231 linker to not dead code strip this symbol. */
232 void (*mark_decl_preserved) (const char *);
234 /* Output a record of the command line switches that have been passed. */
235 print_switch_fn_type record_gcc_switches;
236 /* The name of the section that the example ELF implementation of
237 record_gcc_switches will use to store the information. Target
238 specific versions of record_gcc_switches may or may not use
240 const char * record_gcc_switches_section;
242 /* Output the definition of a section anchor. */
243 void (*output_anchor) (rtx);
245 /* Output a DTP-relative reference to a TLS symbol. */
246 void (*output_dwarf_dtprel) (FILE *file, int size, rtx x);
250 /* Functions relating to instruction scheduling. */
253 /* Given the current cost, COST, of an insn, INSN, calculate and
254 return a new cost based on its relationship to DEP_INSN through
255 the dependence LINK. The default is to make no adjustment. */
256 int (* adjust_cost) (rtx insn, rtx link, rtx dep_insn, int cost);
258 /* Adjust the priority of an insn as you see fit. Returns the new
260 int (* adjust_priority) (rtx, int);
262 /* Function which returns the maximum number of insns that can be
263 scheduled in the same machine cycle. This must be constant
264 over an entire compilation. The default is 1. */
265 int (* issue_rate) (void);
267 /* Calculate how much this insn affects how many more insns we
268 can emit this cycle. Default is they all cost the same. */
269 int (* variable_issue) (FILE *, int, rtx, int);
271 /* Initialize machine-dependent scheduling code. */
272 void (* md_init) (FILE *, int, int);
274 /* Finalize machine-dependent scheduling code. */
275 void (* md_finish) (FILE *, int);
277 /* Initialize machine-dependent function while scheduling code. */
278 void (* md_init_global) (FILE *, int, int);
280 /* Finalize machine-dependent function wide scheduling code. */
281 void (* md_finish_global) (FILE *, int);
283 /* Reorder insns in a machine-dependent fashion, in two different
284 places. Default does nothing. */
285 int (* reorder) (FILE *, int, rtx *, int *, int);
286 int (* reorder2) (FILE *, int, rtx *, int *, int);
288 /* The following member value is a pointer to a function called
289 after evaluation forward dependencies of insns in chain given
290 by two parameter values (head and tail correspondingly). */
291 void (* dependencies_evaluation_hook) (rtx, rtx);
293 /* The values of the following four members are pointers to
294 functions used to simplify the automaton descriptions.
295 dfa_pre_cycle_insn and dfa_post_cycle_insn give functions
296 returning insns which are used to change the pipeline hazard
297 recognizer state when the new simulated processor cycle
298 correspondingly starts and finishes. The function defined by
299 init_dfa_pre_cycle_insn and init_dfa_post_cycle_insn are used
300 to initialize the corresponding insns. The default values of
301 the members result in not changing the automaton state when
302 the new simulated processor cycle correspondingly starts and
304 void (* init_dfa_pre_cycle_insn) (void);
305 rtx (* dfa_pre_cycle_insn) (void);
306 void (* init_dfa_post_cycle_insn) (void);
307 rtx (* dfa_post_cycle_insn) (void);
309 /* The values of the following two members are pointers to
310 functions used to simplify the automaton descriptions.
311 dfa_pre_advance_cycle and dfa_post_advance_cycle are getting called
312 immediately before and after cycle is advanced. */
313 void (* dfa_pre_advance_cycle) (void);
314 void (* dfa_post_advance_cycle) (void);
316 /* The following member value is a pointer to a function returning value
317 which defines how many insns in queue `ready' will we try for
318 multi-pass scheduling. If the member value is nonzero and the
319 function returns positive value, the DFA based scheduler will make
320 multi-pass scheduling for the first cycle. In other words, we will
321 try to choose ready insn which permits to start maximum number of
322 insns on the same cycle. */
323 int (* first_cycle_multipass_dfa_lookahead) (void);
325 /* The following member value is pointer to a function controlling
326 what insns from the ready insn queue will be considered for the
327 multipass insn scheduling. If the hook returns zero for insn
328 passed as the parameter, the insn will be not chosen to be
330 int (* first_cycle_multipass_dfa_lookahead_guard) (rtx);
332 /* The following member value is pointer to a function called by
333 the insn scheduler before issuing insn passed as the third
334 parameter on given cycle. If the hook returns nonzero, the
335 insn is not issued on given processors cycle. Instead of that,
336 the processor cycle is advanced. If the value passed through
337 the last parameter is zero, the insn ready queue is not sorted
338 on the new cycle start as usually. The first parameter passes
339 file for debugging output. The second one passes the scheduler
340 verbose level of the debugging output. The forth and the fifth
341 parameter values are correspondingly processor cycle on which
342 the previous insn has been issued and the current processor
344 int (* dfa_new_cycle) (FILE *, int, rtx, int, int, int *);
346 /* The following member value is a pointer to a function called by the
347 insn scheduler. It should return true if there exists a dependence
348 which is considered costly by the target, between the insn
349 DEP_PRO (&_DEP), and the insn DEP_CON (&_DEP). The first parameter is
350 the dep that represents the dependence between the two insns. The
351 second argument is the cost of the dependence as estimated by
352 the scheduler. The last argument is the distance in cycles
353 between the already scheduled insn (first parameter) and the
354 the second insn (second parameter). */
355 bool (* is_costly_dependence) (struct _dep *_dep, int, int);
357 /* The following member value is a pointer to a function called
358 by the insn scheduler. This hook is called to notify the backend
359 that new instructions were emitted. */
360 void (* h_i_d_extended) (void);
362 /* The following member value is a pointer to a function called
363 by the insn scheduler.
364 The first parameter is an instruction, the second parameter is the type
365 of the requested speculation, and the third parameter is a pointer to the
366 speculative pattern of the corresponding type (set if return value == 1).
368 -1, if there is no pattern, that will satisfy the requested speculation
370 0, if current pattern satisfies the requested speculation type,
371 1, if pattern of the instruction should be changed to the newly
373 int (* speculate_insn) (rtx, int, rtx *);
375 /* The following member value is a pointer to a function called
376 by the insn scheduler. It should return true if the check instruction
377 corresponding to the instruction passed as the parameter needs a
379 bool (* needs_block_p) (const_rtx);
381 /* The following member value is a pointer to a function called
382 by the insn scheduler. It should return a pattern for the check
384 The first parameter is a speculative instruction, the second parameter
385 is the label of the corresponding recovery block (or null, if it is a
386 simple check). If the mutation of the check is requested (e.g. from
387 ld.c to chk.a), the third parameter is true - in this case the first
388 parameter is the previous check. */
389 rtx (* gen_check) (rtx, rtx, bool);
391 /* The following member value is a pointer to a function controlling
392 what insns from the ready insn queue will be considered for the
393 multipass insn scheduling. If the hook returns zero for the insn
394 passed as the parameter, the insn will not be chosen to be
395 issued. This hook is used to discard speculative instructions,
396 that stand at the first position of the ready list. */
397 bool (* first_cycle_multipass_dfa_lookahead_guard_spec) (const_rtx);
399 /* The following member value is a pointer to a function that provides
400 information about the speculation capabilities of the target.
401 The parameter is a pointer to spec_info variable. */
402 void (* set_sched_flags) (struct spec_info_def *);
404 /* The following member value is a pointer to a function that provides
405 information about the target resource-based lower bound which is
406 used by the swing modulo scheduler. The parameter is a pointer
408 int (* sms_res_mii) (struct ddg *);
411 /* Functions relating to vectorization. */
414 /* The following member value is a pointer to a function called
415 by the vectorizer, and return the decl of the target builtin
417 tree (* builtin_mask_for_load) (void);
419 /* Returns a code for builtin that realizes vectorized version of
420 function, or NULL_TREE if not available. */
421 tree (* builtin_vectorized_function) (unsigned, tree, tree);
423 /* Returns a code for builtin that realizes vectorized version of
424 conversion, or NULL_TREE if not available. */
425 tree (* builtin_conversion) (unsigned, tree);
427 /* Target builtin that implements vector widening multiplication.
428 builtin_mul_widen_eve computes the element-by-element products
429 for the even elements, and builtin_mul_widen_odd computes the
430 element-by-element products for the odd elements. */
431 tree (* builtin_mul_widen_even) (tree);
432 tree (* builtin_mul_widen_odd) (tree);
434 /* Returns the cost to be added to the overheads involved with
435 executing the vectorized version of a loop. */
436 int (*builtin_vectorization_cost) (bool);
438 /* Return true if vector alignment is reachable (by peeling N
439 iterations) for the given type. */
440 bool (* vector_alignment_reachable) (const_tree, bool);
443 /* The initial value of target_flags. */
444 int default_target_flags;
446 /* Handle target switch CODE (an OPT_* value). ARG is the argument
447 passed to the switch; it is NULL if no argument was. VALUE is the
448 value of ARG if CODE specifies a UInteger option, otherwise it is
449 1 if the positive form of the switch was used and 0 if the negative
450 form was. Return true if the switch was valid. */
451 bool (* handle_option) (size_t code, const char *arg, int value);
453 /* Display extra, target specific information in response to a
454 --target-help switch. */
455 void (* target_help) (void);
457 /* Return machine mode for filter value. */
458 enum machine_mode (* eh_return_filter_mode) (void);
460 /* Return machine mode for libgcc expanded cmp instructions. */
461 enum machine_mode (* libgcc_cmp_return_mode) (void);
463 /* Return machine mode for libgcc expanded shift instructions. */
464 enum machine_mode (* libgcc_shift_count_mode) (void);
466 /* Given two decls, merge their attributes and return the result. */
467 tree (* merge_decl_attributes) (tree, tree);
469 /* Given two types, merge their attributes and return the result. */
470 tree (* merge_type_attributes) (tree, tree);
472 /* Table of machine attributes and functions to handle them.
474 const struct attribute_spec *attribute_table;
476 /* Return zero if the attributes on TYPE1 and TYPE2 are incompatible,
477 one if they are compatible and two if they are nearly compatible
478 (which causes a warning to be generated). */
479 int (* comp_type_attributes) (const_tree type1, const_tree type2);
481 /* Assign default attributes to the newly defined TYPE. */
482 void (* set_default_type_attributes) (tree type);
484 /* Insert attributes on the newly created DECL. */
485 void (* insert_attributes) (tree decl, tree *attributes);
487 /* Return true if FNDECL (which has at least one machine attribute)
488 can be inlined despite its machine attributes, false otherwise. */
489 bool (* function_attribute_inlinable_p) (const_tree fndecl);
491 /* Return true if bitfields in RECORD_TYPE should follow the
492 Microsoft Visual C++ bitfield layout rules. */
493 bool (* ms_bitfield_layout_p) (const_tree record_type);
495 /* True if the target supports decimal floating point. */
496 bool (* decimal_float_supported_p) (void);
498 /* True if the target supports fixed-point. */
499 bool (* fixed_point_supported_p) (void);
501 /* Return true if anonymous bitfields affect structure alignment. */
502 bool (* align_anon_bitfield) (void);
504 /* Return true if volatile bitfields should use the narrowest type possible.
505 Return false if they should use the container type. */
506 bool (* narrow_volatile_bitfield) (void);
508 /* Set up target-specific built-in functions. */
509 void (* init_builtins) (void);
511 /* Expand a target-specific builtin. */
512 rtx (* expand_builtin) (tree exp, rtx target, rtx subtarget,
513 enum machine_mode mode, int ignore);
515 /* Select a replacement for a target-specific builtin. This is done
516 *before* regular type checking, and so allows the target to implement
517 a crude form of function overloading. The result is a complete
518 expression that implements the operation. */
519 tree (*resolve_overloaded_builtin) (tree decl, tree params);
521 /* Fold a target-specific builtin. */
522 tree (* fold_builtin) (tree fndecl, tree arglist, bool ignore);
524 /* Returns a code for a target-specific builtin that implements
525 reciprocal of the function, or NULL_TREE if not available. */
526 tree (* builtin_reciprocal) (unsigned, bool, bool);
528 /* For a vendor-specific TYPE, return a pointer to a statically-allocated
529 string containing the C++ mangling for TYPE. In all other cases, return
531 const char * (* mangle_type) (const_tree type);
533 /* Make any adjustments to libfunc names needed for this target. */
534 void (* init_libfuncs) (void);
536 /* Given a decl, a section name, and whether the decl initializer
537 has relocs, choose attributes for the section. */
538 /* ??? Should be merged with SELECT_SECTION and UNIQUE_SECTION. */
539 unsigned int (* section_type_flags) (tree, const char *, int);
541 /* True if new jumps cannot be created, to replace existing ones or
542 not, at the current point in the compilation. */
543 bool (* cannot_modify_jumps_p) (void);
545 /* Return a register class for which branch target register
546 optimizations should be applied. */
547 int (* branch_target_register_class) (void);
549 /* Return true if branch target register optimizations should include
550 callee-saved registers that are not already live during the current
551 function. AFTER_PE_GEN is true if prologues and epilogues have
552 already been generated. */
553 bool (* branch_target_register_callee_saved) (bool after_pe_gen);
555 /* True if the constant X cannot be placed in the constant pool. */
556 bool (* cannot_force_const_mem) (rtx);
558 /* True if the insn X cannot be duplicated. */
559 bool (* cannot_copy_insn_p) (rtx);
561 /* True if X is considered to be commutative. */
562 bool (* commutative_p) (const_rtx, int);
564 /* Given an address RTX, undo the effects of LEGITIMIZE_ADDRESS. */
565 rtx (* delegitimize_address) (rtx);
567 /* True if the given constant can be put into an object_block. */
568 bool (* use_blocks_for_constant_p) (enum machine_mode, const_rtx);
570 /* The minimum and maximum byte offsets for anchored addresses. */
571 HOST_WIDE_INT min_anchor_offset;
572 HOST_WIDE_INT max_anchor_offset;
574 /* True if section anchors can be used to access the given symbol. */
575 bool (* use_anchors_for_symbol_p) (const_rtx);
577 /* True if it is OK to do sibling call optimization for the specified
578 call expression EXP. DECL will be the called function, or NULL if
579 this is an indirect call. */
580 bool (*function_ok_for_sibcall) (tree decl, tree exp);
582 /* Establish appropriate back-end context for processing the function
583 FNDECL. The argument might be NULL to indicate processing at top
584 level, outside of any function scope. */
585 void (*set_current_function) (tree fndecl);
587 /* True if EXP should be placed in a "small data" section. */
588 bool (* in_small_data_p) (const_tree);
590 /* True if EXP names an object for which name resolution must resolve
591 to the current module. */
592 bool (* binds_local_p) (const_tree);
594 /* Modify and return the identifier of a DECL's external name,
595 originally identified by ID, as required by the target,
596 (eg, append @nn to windows32 stdcall function names).
597 The default is to return ID without modification. */
598 tree (* mangle_decl_assembler_name) (tree decl, tree id);
600 /* Do something target-specific to record properties of the DECL into
601 the associated SYMBOL_REF. */
602 void (* encode_section_info) (tree, rtx, int);
604 /* Undo the effects of encode_section_info on the symbol string. */
605 const char * (* strip_name_encoding) (const char *);
607 /* If shift optabs for MODE are known to always truncate the shift count,
608 return the mask that they apply. Return 0 otherwise. */
609 unsigned HOST_WIDE_INT (* shift_truncation_mask) (enum machine_mode mode);
611 /* Return the number of divisions in the given MODE that should be present,
612 so that it is profitable to turn the division into a multiplication by
614 unsigned int (* min_divisions_for_recip_mul) (enum machine_mode mode);
616 /* If the representation of integral MODE is such that values are
617 always sign-extended to a wider mode MODE_REP then return
618 SIGN_EXTEND. Return UNKNOWN otherwise. */
619 /* Note that the return type ought to be RTX_CODE, but that's not
620 necessarily defined at this point. */
621 int (* mode_rep_extended) (enum machine_mode mode,
622 enum machine_mode mode_rep);
624 /* True if MODE is valid for a pointer in __attribute__((mode("MODE"))). */
625 bool (* valid_pointer_mode) (enum machine_mode mode);
627 /* True if MODE is valid for the target. By "valid", we mean able to
628 be manipulated in non-trivial ways. In particular, this means all
629 the arithmetic is supported. */
630 bool (* scalar_mode_supported_p) (enum machine_mode mode);
632 /* Similarly for vector modes. "Supported" here is less strict. At
633 least some operations are supported; need to check optabs or builtins
634 for further details. */
635 bool (* vector_mode_supported_p) (enum machine_mode mode);
637 /* True if a vector is opaque. */
638 bool (* vector_opaque_p) (const_tree);
640 /* Compute a (partial) cost for rtx X. Return true if the complete
641 cost has been computed, and false if subexpressions should be
642 scanned. In either case, *TOTAL contains the cost result. */
643 /* Note that CODE and OUTER_CODE ought to be RTX_CODE, but that's
644 not necessarily defined at this point. */
645 bool (* rtx_costs) (rtx x, int code, int outer_code, int *total);
647 /* Compute the cost of X, used as an address. Never called with
648 invalid addresses. */
649 int (* address_cost) (rtx x);
651 /* Return where to allocate pseudo for a given hard register initial
653 rtx (* allocate_initial_value) (rtx x);
655 /* Return nonzero if evaluating UNSPEC[_VOLATILE] X might cause a trap.
656 FLAGS has the same meaning as in rtlanal.c: may_trap_p_1. */
657 int (* unspec_may_trap_p) (const_rtx x, unsigned flags);
659 /* Given a register, this hook should return a parallel of registers
660 to represent where to find the register pieces. Define this hook
661 if the register and its mode are represented in Dwarf in
662 non-contiguous locations, or if the register should be
663 represented in more than one register in Dwarf. Otherwise, this
664 hook should return NULL_RTX. */
665 rtx (* dwarf_register_span) (rtx);
667 /* If expand_builtin_init_dwarf_reg_sizes needs to fill in table
668 entries not corresponding directly to registers below
669 FIRST_PSEUDO_REGISTER, this hook should generate the necessary
670 code, given the address of the table. */
671 void (* init_dwarf_reg_sizes_extra) (tree);
673 /* Fetch the fixed register(s) which hold condition codes, for
674 targets where it makes sense to look for duplicate assignments to
675 the condition codes. This should return true if there is such a
676 register, false otherwise. The arguments should be set to the
677 fixed register numbers. Up to two condition code registers are
678 supported. If there is only one for this target, the int pointed
679 at by the second argument should be set to -1. */
680 bool (* fixed_condition_code_regs) (unsigned int *, unsigned int *);
682 /* If two condition code modes are compatible, return a condition
683 code mode which is compatible with both, such that a comparison
684 done in the returned mode will work for both of the original
685 modes. If the condition code modes are not compatible, return
687 enum machine_mode (* cc_modes_compatible) (enum machine_mode,
690 /* Do machine-dependent code transformations. Called just before
691 delayed-branch scheduling. */
692 void (* machine_dependent_reorg) (void);
694 /* Create the __builtin_va_list type. */
695 tree (* build_builtin_va_list) (void);
697 /* Expand the __builtin_va_start builtin. */
698 void (* expand_builtin_va_start) (tree valist, rtx nextarg);
700 /* Gimplifies a VA_ARG_EXPR. */
701 tree (* gimplify_va_arg_expr) (tree valist, tree type, tree *pre_p,
704 /* Validity-checking routines for PCH files, target-specific.
705 get_pch_validity returns a pointer to the data to be stored,
706 and stores the size in its argument. pch_valid_p gets the same
707 information back and returns NULL if the PCH is valid,
708 or an error message if not.
710 void * (* get_pch_validity) (size_t *);
711 const char * (* pch_valid_p) (const void *, size_t);
713 /* If nonnull, this function checks whether a PCH file with the
714 given set of target flags can be used. It returns NULL if so,
715 otherwise it returns an error message. */
716 const char *(*check_pch_target_flags) (int);
718 /* True if the compiler should give an enum type only as many
719 bytes as it takes to represent the range of possible values of
721 bool (* default_short_enums) (void);
723 /* This target hook returns an rtx that is used to store the address
724 of the current frame into the built-in setjmp buffer. */
725 rtx (* builtin_setjmp_frame_value) (void);
727 /* This target hook should add STRING_CST trees for any hard regs
728 the port wishes to automatically clobber for an asm. */
729 tree (* md_asm_clobbers) (tree, tree, tree);
731 /* This target hook allows the backend to specify a calling convention
732 in the debug information. This function actually returns an
733 enum dwarf_calling_convention, but because of forward declarations
734 and not wanting to include dwarf2.h everywhere target.h is included
735 the function is being declared as an int. */
736 int (* dwarf_calling_convention) (const_tree);
738 /* This target hook allows the backend to emit frame-related insns that
739 contain UNSPECs or UNSPEC_VOLATILEs. The call frame debugging info
740 engine will invoke it on insns of the form
741 (set (reg) (unspec [...] UNSPEC_INDEX))
743 (set (reg) (unspec_volatile [...] UNSPECV_INDEX))
744 to let the backend emit the call frame instructions. */
745 void (* dwarf_handle_frame_unspec) (const char *, rtx, int);
747 /* Perform architecture specific checking of statements gimplified
748 from VA_ARG_EXPR. LHS is left hand side of MODIFY_EXPR, RHS
749 is right hand side. Returns true if the statements doesn't need
750 to be checked for va_list references. */
751 bool (* stdarg_optimize_hook) (struct stdarg_info *ai, const_tree lhs, const_tree rhs);
753 /* This target hook allows the operating system to override the DECL
754 that represents the external variable that contains the stack
755 protection guard variable. The type of this DECL is ptr_type_node. */
756 tree (* stack_protect_guard) (void);
758 /* This target hook allows the operating system to override the CALL_EXPR
759 that is invoked when a check vs the guard variable fails. */
760 tree (* stack_protect_fail) (void);
762 /* Returns NULL if target supports the insn within a doloop block,
763 otherwise it returns an error message. */
764 const char * (*invalid_within_doloop) (const_rtx);
766 /* DECL is a variable or function with __attribute__((dllimport))
767 specified. Use this hook if the target needs to add extra validation
768 checks to handle_dll_attribute (). */
769 bool (* valid_dllimport_attribute_p) (const_tree decl);
771 /* Functions relating to calls - argument passing, returns, etc. */
773 bool (*promote_function_args) (const_tree fntype);
774 bool (*promote_function_return) (const_tree fntype);
775 bool (*promote_prototypes) (const_tree fntype);
776 rtx (*struct_value_rtx) (tree fndecl, int incoming);
777 bool (*return_in_memory) (const_tree type, const_tree fndecl);
778 bool (*return_in_msb) (const_tree type);
780 /* Return true if a parameter must be passed by reference. TYPE may
781 be null if this is a libcall. CA may be null if this query is
782 from __builtin_va_arg. */
783 bool (*pass_by_reference) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
784 const_tree type, bool named_arg);
786 rtx (*expand_builtin_saveregs) (void);
787 /* Returns pretend_argument_size. */
788 void (*setup_incoming_varargs) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
789 tree type, int *pretend_arg_size,
791 bool (*strict_argument_naming) (CUMULATIVE_ARGS *ca);
792 /* Returns true if we should use
793 targetm.calls.setup_incoming_varargs() and/or
794 targetm.calls.strict_argument_naming(). */
795 bool (*pretend_outgoing_varargs_named) (CUMULATIVE_ARGS *ca);
797 /* Given a complex type T, return true if a parameter of type T
798 should be passed as two scalars. */
799 bool (* split_complex_arg) (const_tree type);
801 /* Return true if type T, mode MODE, may not be passed in registers,
802 but must be passed on the stack. */
803 /* ??? This predicate should be applied strictly after pass-by-reference.
804 Need audit to verify that this is the case. */
805 bool (* must_pass_in_stack) (enum machine_mode mode, const_tree t);
807 /* Return true if type TYPE, mode MODE, which is passed by reference,
808 should have the object copy generated by the callee rather than
809 the caller. It is never called for TYPE requiring constructors. */
810 bool (* callee_copies) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
811 const_tree type, bool named);
813 /* Return zero for arguments passed entirely on the stack or entirely
814 in registers. If passed in both, return the number of bytes passed
815 in registers; the balance is therefore passed on the stack. */
816 int (* arg_partial_bytes) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
817 tree type, bool named);
819 /* Return the diagnostic message string if function without a prototype
820 is not allowed for this 'val' argument; NULL otherwise. */
821 const char *(*invalid_arg_for_unprototyped_fn) (const_tree typelist,
825 /* Return an rtx for the return value location of the function
826 specified by FN_DECL_OR_TYPE with a return type of RET_TYPE. */
827 rtx (*function_value) (const_tree ret_type, const_tree fn_decl_or_type,
830 /* Return an rtx for the argument pointer incoming to the
832 rtx (*internal_arg_pointer) (void);
835 /* Return the diagnostic message string if conversion from FROMTYPE
836 to TOTYPE is not allowed, NULL otherwise. */
837 const char *(*invalid_conversion) (const_tree fromtype, const_tree totype);
839 /* Return the diagnostic message string if the unary operation OP is
840 not permitted on TYPE, NULL otherwise. */
841 const char *(*invalid_unary_op) (int op, const_tree type);
843 /* Return the diagnostic message string if the binary operation OP
844 is not permitted on TYPE1 and TYPE2, NULL otherwise. */
845 const char *(*invalid_binary_op) (int op, const_tree type1, const_tree type2);
847 /* Return the class for a secondary reload, and fill in extra information. */
848 enum reg_class (*secondary_reload) (bool, rtx, enum reg_class,
850 struct secondary_reload_info *);
852 /* This target hook allows the backend to perform additional
853 processing while initializing for variable expansion. */
854 void (* expand_to_rtl_hook) (void);
856 /* This target hook allows the backend to perform additional
857 instantiations on rtx that are not actually in insns yet,
858 but will be later. */
859 void (* instantiate_decls) (void);
861 /* Functions specific to the C family of frontends. */
863 /* Return machine mode for non-standard suffix
864 or VOIDmode if non-standard suffixes are unsupported. */
865 enum machine_mode (*mode_for_suffix) (char);
868 /* Functions specific to the C++ frontend. */
870 /* Return the integer type used for guard variables. */
871 tree (*guard_type) (void);
872 /* Return true if only the low bit of the guard should be tested. */
873 bool (*guard_mask_bit) (void);
874 /* Returns the size of the array cookie for an array of type. */
875 tree (*get_cookie_size) (tree);
876 /* Returns true if the element size should be stored in the
878 bool (*cookie_has_size) (void);
879 /* Allows backends to perform additional processing when
880 deciding if a class should be exported or imported. */
881 int (*import_export_class) (tree, int);
882 /* Returns true if constructors and destructors return "this". */
883 bool (*cdtor_returns_this) (void);
884 /* Returns true if the key method for a class can be an inline
885 function, so long as it is not declared inline in the class
886 itself. Returning true is the behavior required by the Itanium
888 bool (*key_method_may_be_inline) (void);
889 /* DECL is a virtual table, virtual table table, typeinfo object,
890 or other similar implicit class data object that will be
891 emitted with external linkage in this translation unit. No ELF
892 visibility has been explicitly specified. If the target needs
893 to specify a visibility other than that of the containing class,
894 use this hook to set DECL_VISIBILITY and
895 DECL_VISIBILITY_SPECIFIED. */
896 void (*determine_class_data_visibility) (tree decl);
897 /* Returns true (the default) if virtual tables and other
898 similar implicit class data objects are always COMDAT if they
899 have external linkage. If this hook returns false, then
900 class data for classes whose virtual table will be emitted in
901 only one translation unit will not be COMDAT. */
902 bool (*class_data_always_comdat) (void);
903 /* Returns true (the default) if the RTTI for the basic types,
904 which is always defined in the C++ runtime, should be COMDAT;
905 false if it should not be COMDAT. */
906 bool (*library_rtti_comdat) (void);
907 /* Returns true if __aeabi_atexit should be used to register static
909 bool (*use_aeabi_atexit) (void);
910 /* Returns true if target may use atexit in the same manner as
911 __cxa_atexit to register static destructors. */
912 bool (*use_atexit_for_cxa_atexit) (void);
913 /* TYPE is a C++ class (i.e., RECORD_TYPE or UNION_TYPE) that
914 has just been defined. Use this hook to make adjustments to the
915 class (eg, tweak visibility or perform any other required
916 target modifications). */
917 void (*adjust_class_at_definition) (tree type);
920 /* For targets that need to mark extra registers as live on entry to
921 the function, they should define this target hook and set their
922 bits in the bitmap passed in. */
923 void (*live_on_entry) (bitmap);
925 /* True if unwinding tables should be generated by default. */
926 bool unwind_tables_default;
928 /* Leave the boolean fields at the end. */
930 /* True if arbitrary sections are supported. */
931 bool have_named_sections;
933 /* True if we can create zeroed data by switching to a BSS section
934 and then using ASM_OUTPUT_SKIP to allocate the space. */
935 bool have_switchable_bss_sections;
937 /* True if "native" constructors and destructors are supported,
938 false if we're using collect2 for the job. */
939 bool have_ctors_dtors;
941 /* True if thread-local storage is supported. */
944 /* True if a small readonly data section is supported. */
945 bool have_srodata_section;
947 /* True if EH frame info sections should be zero-terminated. */
948 bool terminate_dw2_eh_frame_info;
950 /* True if #NO_APP should be emitted at the beginning of
952 bool file_start_app_off;
954 /* True if output_file_directive should be called for main_input_filename
955 at the beginning of assembly output. */
956 bool file_start_file_directive;
958 /* True if #pragma redefine_extname is to be supported. */
959 bool handle_pragma_redefine_extname;
961 /* True if #pragma extern_prefix is to be supported. */
962 bool handle_pragma_extern_prefix;
964 /* True if the target is allowed to reorder memory accesses unless
965 synchronization is explicitly requested. */
966 bool relaxed_ordering;
968 /* Returns true if we should generate exception tables for use with the
969 ARM EABI. The effects the encoding of function exception specifications.
971 bool arm_eabi_unwinder;
973 /* Leave the boolean fields at the end. */
976 extern struct gcc_target targetm;
978 struct gcc_targetcm {
979 /* Handle target switch CODE (an OPT_* value). ARG is the argument
980 passed to the switch; it is NULL if no argument was. VALUE is the
981 value of ARG if CODE specifies a UInteger option, otherwise it is
982 1 if the positive form of the switch was used and 0 if the negative
983 form was. Return true if the switch was valid. */
984 bool (*handle_c_option) (size_t code, const char *arg, int value);
987 /* Each target can provide their own. */
988 extern struct gcc_targetcm targetcm;
990 #endif /* GCC_TARGET_H */
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