1 /* Data structure definitions for a generic GCC target.
2 Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
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);
248 /* Some target machines need to postscan each insn after it is output. */
249 void (*final_postscan_insn) (FILE *, rtx, rtx *, int);
252 /* Functions relating to instruction scheduling. */
255 /* Given the current cost, COST, of an insn, INSN, calculate and
256 return a new cost based on its relationship to DEP_INSN through
257 the dependence LINK. The default is to make no adjustment. */
258 int (* adjust_cost) (rtx insn, rtx link, rtx dep_insn, int cost);
260 /* Adjust the priority of an insn as you see fit. Returns the new
262 int (* adjust_priority) (rtx, int);
264 /* Function which returns the maximum number of insns that can be
265 scheduled in the same machine cycle. This must be constant
266 over an entire compilation. The default is 1. */
267 int (* issue_rate) (void);
269 /* Calculate how much this insn affects how many more insns we
270 can emit this cycle. Default is they all cost the same. */
271 int (* variable_issue) (FILE *, int, rtx, int);
273 /* Initialize machine-dependent scheduling code. */
274 void (* md_init) (FILE *, int, int);
276 /* Finalize machine-dependent scheduling code. */
277 void (* md_finish) (FILE *, int);
279 /* Initialize machine-dependent function wide scheduling code. */
280 void (* md_init_global) (FILE *, int, int);
282 /* Finalize machine-dependent function wide scheduling code. */
283 void (* md_finish_global) (FILE *, int);
285 /* Reorder insns in a machine-dependent fashion, in two different
286 places. Default does nothing. */
287 int (* reorder) (FILE *, int, rtx *, int *, int);
288 int (* reorder2) (FILE *, int, rtx *, int *, int);
290 /* The following member value is a pointer to a function called
291 after evaluation forward dependencies of insns in chain given
292 by two parameter values (head and tail correspondingly). */
293 void (* dependencies_evaluation_hook) (rtx, rtx);
295 /* The values of the following four members are pointers to
296 functions used to simplify the automaton descriptions.
297 dfa_pre_cycle_insn and dfa_post_cycle_insn give functions
298 returning insns which are used to change the pipeline hazard
299 recognizer state when the new simulated processor cycle
300 correspondingly starts and finishes. The function defined by
301 init_dfa_pre_cycle_insn and init_dfa_post_cycle_insn are used
302 to initialize the corresponding insns. The default values of
303 the members result in not changing the automaton state when
304 the new simulated processor cycle correspondingly starts and
306 void (* init_dfa_pre_cycle_insn) (void);
307 rtx (* dfa_pre_cycle_insn) (void);
308 void (* init_dfa_post_cycle_insn) (void);
309 rtx (* dfa_post_cycle_insn) (void);
311 /* The values of the following two members are pointers to
312 functions used to simplify the automaton descriptions.
313 dfa_pre_advance_cycle and dfa_post_advance_cycle are getting called
314 immediately before and after cycle is advanced. */
315 void (* dfa_pre_advance_cycle) (void);
316 void (* dfa_post_advance_cycle) (void);
318 /* The following member value is a pointer to a function returning value
319 which defines how many insns in queue `ready' will we try for
320 multi-pass scheduling. If the member value is nonzero and the
321 function returns positive value, the DFA based scheduler will make
322 multi-pass scheduling for the first cycle. In other words, we will
323 try to choose ready insn which permits to start maximum number of
324 insns on the same cycle. */
325 int (* first_cycle_multipass_dfa_lookahead) (void);
327 /* The following member value is pointer to a function controlling
328 what insns from the ready insn queue will be considered for the
329 multipass insn scheduling. If the hook returns zero for insn
330 passed as the parameter, the insn will be not chosen to be
332 int (* first_cycle_multipass_dfa_lookahead_guard) (rtx);
334 /* The following member value is pointer to a function called by
335 the insn scheduler before issuing insn passed as the third
336 parameter on given cycle. If the hook returns nonzero, the
337 insn is not issued on given processors cycle. Instead of that,
338 the processor cycle is advanced. If the value passed through
339 the last parameter is zero, the insn ready queue is not sorted
340 on the new cycle start as usually. The first parameter passes
341 file for debugging output. The second one passes the scheduler
342 verbose level of the debugging output. The forth and the fifth
343 parameter values are correspondingly processor cycle on which
344 the previous insn has been issued and the current processor
346 int (* dfa_new_cycle) (FILE *, int, rtx, int, int, int *);
348 /* The following member value is a pointer to a function called by the
349 insn scheduler. It should return true if there exists a dependence
350 which is considered costly by the target, between the insn
351 DEP_PRO (&_DEP), and the insn DEP_CON (&_DEP). The first parameter is
352 the dep that represents the dependence between the two insns. The
353 second argument is the cost of the dependence as estimated by
354 the scheduler. The last argument is the distance in cycles
355 between the already scheduled insn (first parameter) and the
356 second insn (second parameter). */
357 bool (* is_costly_dependence) (struct _dep *_dep, int, int);
359 /* Given the current cost, COST, of an insn, INSN, calculate and
360 return a new cost based on its relationship to DEP_INSN through the
361 dependence of type DEP_TYPE. The default is to make no adjustment. */
362 int (* adjust_cost_2) (rtx insn, int, rtx dep_insn, int cost, int dw);
364 /* The following member value is a pointer to a function called
365 by the insn scheduler. This hook is called to notify the backend
366 that new instructions were emitted. */
367 void (* h_i_d_extended) (void);
369 /* Next 5 functions are for multi-point scheduling. */
371 /* Allocate memory for scheduler context. */
372 void *(* alloc_sched_context) (void);
374 /* Fills the context from the local machine scheduler context. */
375 void (* init_sched_context) (void *, bool);
377 /* Sets local machine scheduler context to a saved value. */
378 void (* set_sched_context) (void *);
380 /* Clears a scheduler context so it becomes like after init. */
381 void (* clear_sched_context) (void *);
383 /* Frees the scheduler context. */
384 void (* free_sched_context) (void *);
386 /* The following member value is a pointer to a function called
387 by the insn scheduler.
388 The first parameter is an instruction, the second parameter is the type
389 of the requested speculation, and the third parameter is a pointer to the
390 speculative pattern of the corresponding type (set if return value == 1).
392 -1, if there is no pattern, that will satisfy the requested speculation
394 0, if current pattern satisfies the requested speculation type,
395 1, if pattern of the instruction should be changed to the newly
397 int (* speculate_insn) (rtx, int, rtx *);
399 /* The following member value is a pointer to a function called
400 by the insn scheduler. It should return true if the check instruction
401 passed as the parameter needs a recovery block. */
402 bool (* needs_block_p) (int);
404 /* The following member value is a pointer to a function called
405 by the insn scheduler. It should return a pattern for the check
407 The first parameter is a speculative instruction, the second parameter
408 is the label of the corresponding recovery block (or null, if it is a
409 simple check). If the mutation of the check is requested (e.g. from
410 ld.c to chk.a), the third parameter is true - in this case the first
411 parameter is the previous check. */
412 rtx (* gen_spec_check) (rtx, rtx, int);
414 /* The following member value is a pointer to a function controlling
415 what insns from the ready insn queue will be considered for the
416 multipass insn scheduling. If the hook returns zero for the insn
417 passed as the parameter, the insn will not be chosen to be
418 issued. This hook is used to discard speculative instructions,
419 that stand at the first position of the ready list. */
420 bool (* first_cycle_multipass_dfa_lookahead_guard_spec) (const_rtx);
422 /* The following member value is a pointer to a function that provides
423 information about the speculation capabilities of the target.
424 The parameter is a pointer to spec_info variable. */
425 void (* set_sched_flags) (struct spec_info_def *);
427 /* Return speculation types of the instruction passed as the parameter. */
428 int (* get_insn_spec_ds) (rtx);
430 /* Return speculation types that are checked for the instruction passed as
432 int (* get_insn_checked_ds) (rtx);
434 /* Return bool if rtx scanning should just skip current layer and
435 advance to the inner rtxes. */
436 bool (* skip_rtx_p) (const_rtx);
438 /* The following member value is a pointer to a function that provides
439 information about the target resource-based lower bound which is
440 used by the swing modulo scheduler. The parameter is a pointer
442 int (* sms_res_mii) (struct ddg *);
445 /* Functions relating to vectorization. */
448 /* The following member value is a pointer to a function called
449 by the vectorizer, and return the decl of the target builtin
451 tree (* builtin_mask_for_load) (void);
453 /* Returns a code for builtin that realizes vectorized version of
454 function, or NULL_TREE if not available. */
455 tree (* builtin_vectorized_function) (unsigned, tree, tree);
457 /* Returns a code for builtin that realizes vectorized version of
458 conversion, or NULL_TREE if not available. */
459 tree (* builtin_conversion) (unsigned, tree);
461 /* Target builtin that implements vector widening multiplication.
462 builtin_mul_widen_eve computes the element-by-element products
463 for the even elements, and builtin_mul_widen_odd computes the
464 element-by-element products for the odd elements. */
465 tree (* builtin_mul_widen_even) (tree);
466 tree (* builtin_mul_widen_odd) (tree);
468 /* Returns the cost to be added to the overheads involved with
469 executing the vectorized version of a loop. */
470 int (*builtin_vectorization_cost) (bool);
472 /* Return true if vector alignment is reachable (by peeling N
473 iterations) for the given type. */
474 bool (* vector_alignment_reachable) (const_tree, bool);
476 /* Target builtin that implements vector permute. */
477 tree (* builtin_vec_perm) (tree, tree*);
480 /* The initial value of target_flags. */
481 int default_target_flags;
483 /* Handle target switch CODE (an OPT_* value). ARG is the argument
484 passed to the switch; it is NULL if no argument was. VALUE is the
485 value of ARG if CODE specifies a UInteger option, otherwise it is
486 1 if the positive form of the switch was used and 0 if the negative
487 form was. Return true if the switch was valid. */
488 bool (* handle_option) (size_t code, const char *arg, int value);
490 /* Display extra, target specific information in response to a
491 --target-help switch. */
492 void (* target_help) (void);
494 /* Return machine mode for filter value. */
495 enum machine_mode (* eh_return_filter_mode) (void);
497 /* Return machine mode for libgcc expanded cmp instructions. */
498 enum machine_mode (* libgcc_cmp_return_mode) (void);
500 /* Return machine mode for libgcc expanded shift instructions. */
501 enum machine_mode (* libgcc_shift_count_mode) (void);
503 /* Return machine mode to be used for _Unwind_Word type. */
504 enum machine_mode (* unwind_word_mode) (void);
506 /* Given two decls, merge their attributes and return the result. */
507 tree (* merge_decl_attributes) (tree, tree);
509 /* Given two types, merge their attributes and return the result. */
510 tree (* merge_type_attributes) (tree, tree);
512 /* Table of machine attributes and functions to handle them.
514 const struct attribute_spec *attribute_table;
516 /* Return zero if the attributes on TYPE1 and TYPE2 are incompatible,
517 one if they are compatible and two if they are nearly compatible
518 (which causes a warning to be generated). */
519 int (* comp_type_attributes) (const_tree type1, const_tree type2);
521 /* Assign default attributes to the newly defined TYPE. */
522 void (* set_default_type_attributes) (tree type);
524 /* Insert attributes on the newly created DECL. */
525 void (* insert_attributes) (tree decl, tree *attributes);
527 /* Return true if FNDECL (which has at least one machine attribute)
528 can be inlined despite its machine attributes, false otherwise. */
529 bool (* function_attribute_inlinable_p) (const_tree fndecl);
531 /* Return true if bitfields in RECORD_TYPE should follow the
532 Microsoft Visual C++ bitfield layout rules. */
533 bool (* ms_bitfield_layout_p) (const_tree record_type);
535 /* True if the target supports decimal floating point. */
536 bool (* decimal_float_supported_p) (void);
538 /* True if the target supports fixed-point. */
539 bool (* fixed_point_supported_p) (void);
541 /* Return true if anonymous bitfields affect structure alignment. */
542 bool (* align_anon_bitfield) (void);
544 /* Return true if volatile bitfields should use the narrowest type possible.
545 Return false if they should use the container type. */
546 bool (* narrow_volatile_bitfield) (void);
548 /* Set up target-specific built-in functions. */
549 void (* init_builtins) (void);
551 /* Expand a target-specific builtin. */
552 rtx (* expand_builtin) (tree exp, rtx target, rtx subtarget,
553 enum machine_mode mode, int ignore);
555 /* Select a replacement for a target-specific builtin. This is done
556 *before* regular type checking, and so allows the target to
557 implement a crude form of function overloading. The result is a
558 complete expression that implements the operation. PARAMS really
559 has type VEC(tree,gc)*, but we don't want to include tree.h
561 tree (*resolve_overloaded_builtin) (tree decl, void *params);
563 /* Fold a target-specific builtin. */
564 tree (* fold_builtin) (tree fndecl, tree arglist, bool ignore);
566 /* Returns a code for a target-specific builtin that implements
567 reciprocal of the function, or NULL_TREE if not available. */
568 tree (* builtin_reciprocal) (unsigned, bool, bool);
570 /* For a vendor-specific TYPE, return a pointer to a statically-allocated
571 string containing the C++ mangling for TYPE. In all other cases, return
573 const char * (* mangle_type) (const_tree type);
575 /* Make any adjustments to libfunc names needed for this target. */
576 void (* init_libfuncs) (void);
578 /* Given a decl, a section name, and whether the decl initializer
579 has relocs, choose attributes for the section. */
580 /* ??? Should be merged with SELECT_SECTION and UNIQUE_SECTION. */
581 unsigned int (* section_type_flags) (tree, const char *, int);
583 /* True if new jumps cannot be created, to replace existing ones or
584 not, at the current point in the compilation. */
585 bool (* cannot_modify_jumps_p) (void);
587 /* Return a register class for which branch target register
588 optimizations should be applied. */
589 enum reg_class (* branch_target_register_class) (void);
591 /* Return true if branch target register optimizations should include
592 callee-saved registers that are not already live during the current
593 function. AFTER_PE_GEN is true if prologues and epilogues have
594 already been generated. */
595 bool (* branch_target_register_callee_saved) (bool after_pe_gen);
597 /* True if the constant X cannot be placed in the constant pool. */
598 bool (* cannot_force_const_mem) (rtx);
600 /* True if the insn X cannot be duplicated. */
601 bool (* cannot_copy_insn_p) (rtx);
603 /* True if X is considered to be commutative. */
604 bool (* commutative_p) (const_rtx, int);
606 /* Given an address RTX, undo the effects of LEGITIMIZE_ADDRESS. */
607 rtx (* delegitimize_address) (rtx);
609 /* True if the given constant can be put into an object_block. */
610 bool (* use_blocks_for_constant_p) (enum machine_mode, const_rtx);
612 /* The minimum and maximum byte offsets for anchored addresses. */
613 HOST_WIDE_INT min_anchor_offset;
614 HOST_WIDE_INT max_anchor_offset;
616 /* True if section anchors can be used to access the given symbol. */
617 bool (* use_anchors_for_symbol_p) (const_rtx);
619 /* True if it is OK to do sibling call optimization for the specified
620 call expression EXP. DECL will be the called function, or NULL if
621 this is an indirect call. */
622 bool (*function_ok_for_sibcall) (tree decl, tree exp);
624 /* Establish appropriate back-end context for processing the function
625 FNDECL. The argument might be NULL to indicate processing at top
626 level, outside of any function scope. */
627 void (*set_current_function) (tree fndecl);
629 /* True if EXP should be placed in a "small data" section. */
630 bool (* in_small_data_p) (const_tree);
632 /* True if EXP names an object for which name resolution must resolve
633 to the current executable or shared library. */
634 bool (* binds_local_p) (const_tree);
636 /* Modify and return the identifier of a DECL's external name,
637 originally identified by ID, as required by the target,
638 (eg, append @nn to windows32 stdcall function names).
639 The default is to return ID without modification. */
640 tree (* mangle_decl_assembler_name) (tree decl, tree id);
642 /* Do something target-specific to record properties of the DECL into
643 the associated SYMBOL_REF. */
644 void (* encode_section_info) (tree, rtx, int);
646 /* Undo the effects of encode_section_info on the symbol string. */
647 const char * (* strip_name_encoding) (const char *);
649 /* If shift optabs for MODE are known to always truncate the shift count,
650 return the mask that they apply. Return 0 otherwise. */
651 unsigned HOST_WIDE_INT (* shift_truncation_mask) (enum machine_mode mode);
653 /* Return the number of divisions in the given MODE that should be present,
654 so that it is profitable to turn the division into a multiplication by
656 unsigned int (* min_divisions_for_recip_mul) (enum machine_mode mode);
658 /* If the representation of integral MODE is such that values are
659 always sign-extended to a wider mode MODE_REP then return
660 SIGN_EXTEND. Return UNKNOWN otherwise. */
661 /* Note that the return type ought to be RTX_CODE, but that's not
662 necessarily defined at this point. */
663 int (* mode_rep_extended) (enum machine_mode mode,
664 enum machine_mode mode_rep);
666 /* True if MODE is valid for a pointer in __attribute__((mode("MODE"))). */
667 bool (* valid_pointer_mode) (enum machine_mode mode);
669 /* True if MODE is valid for the target. By "valid", we mean able to
670 be manipulated in non-trivial ways. In particular, this means all
671 the arithmetic is supported. */
672 bool (* scalar_mode_supported_p) (enum machine_mode mode);
674 /* Similarly for vector modes. "Supported" here is less strict. At
675 least some operations are supported; need to check optabs or builtins
676 for further details. */
677 bool (* vector_mode_supported_p) (enum machine_mode mode);
679 /* Compute a (partial) cost for rtx X. Return true if the complete
680 cost has been computed, and false if subexpressions should be
681 scanned. In either case, *TOTAL contains the cost result. */
682 /* Note that CODE and OUTER_CODE ought to be RTX_CODE, but that's
683 not necessarily defined at this point. */
684 bool (* rtx_costs) (rtx x, int code, int outer_code, int *total, bool speed);
686 /* Compute the cost of X, used as an address. Never called with
687 invalid addresses. */
688 int (* address_cost) (rtx x, bool speed);
690 /* Return where to allocate pseudo for a given hard register initial
692 rtx (* allocate_initial_value) (rtx x);
694 /* Return nonzero if evaluating UNSPEC[_VOLATILE] X might cause a trap.
695 FLAGS has the same meaning as in rtlanal.c: may_trap_p_1. */
696 int (* unspec_may_trap_p) (const_rtx x, unsigned flags);
698 /* Given a register, this hook should return a parallel of registers
699 to represent where to find the register pieces. Define this hook
700 if the register and its mode are represented in Dwarf in
701 non-contiguous locations, or if the register should be
702 represented in more than one register in Dwarf. Otherwise, this
703 hook should return NULL_RTX. */
704 rtx (* dwarf_register_span) (rtx);
706 /* If expand_builtin_init_dwarf_reg_sizes needs to fill in table
707 entries not corresponding directly to registers below
708 FIRST_PSEUDO_REGISTER, this hook should generate the necessary
709 code, given the address of the table. */
710 void (* init_dwarf_reg_sizes_extra) (tree);
712 /* Fetch the fixed register(s) which hold condition codes, for
713 targets where it makes sense to look for duplicate assignments to
714 the condition codes. This should return true if there is such a
715 register, false otherwise. The arguments should be set to the
716 fixed register numbers. Up to two condition code registers are
717 supported. If there is only one for this target, the int pointed
718 at by the second argument should be set to -1. */
719 bool (* fixed_condition_code_regs) (unsigned int *, unsigned int *);
721 /* If two condition code modes are compatible, return a condition
722 code mode which is compatible with both, such that a comparison
723 done in the returned mode will work for both of the original
724 modes. If the condition code modes are not compatible, return
726 enum machine_mode (* cc_modes_compatible) (enum machine_mode,
729 /* Do machine-dependent code transformations. Called just before
730 delayed-branch scheduling. */
731 void (* machine_dependent_reorg) (void);
733 /* Create the __builtin_va_list type. */
734 tree (* build_builtin_va_list) (void);
736 /* Get the cfun/fndecl calling abi __builtin_va_list type. */
737 tree (* fn_abi_va_list) (tree);
739 /* Get the __builtin_va_list type dependent on input type. */
740 tree (* canonical_va_list_type) (tree);
742 /* Expand the __builtin_va_start builtin. */
743 void (* expand_builtin_va_start) (tree valist, rtx nextarg);
745 /* Gimplifies a VA_ARG_EXPR. */
746 tree (* gimplify_va_arg_expr) (tree valist, tree type, gimple_seq *pre_p,
749 /* Validity-checking routines for PCH files, target-specific.
750 get_pch_validity returns a pointer to the data to be stored,
751 and stores the size in its argument. pch_valid_p gets the same
752 information back and returns NULL if the PCH is valid,
753 or an error message if not.
755 void * (* get_pch_validity) (size_t *);
756 const char * (* pch_valid_p) (const void *, size_t);
758 /* If nonnull, this function checks whether a PCH file with the
759 given set of target flags can be used. It returns NULL if so,
760 otherwise it returns an error message. */
761 const char *(*check_pch_target_flags) (int);
763 /* True if the compiler should give an enum type only as many
764 bytes as it takes to represent the range of possible values of
766 bool (* default_short_enums) (void);
768 /* This target hook returns an rtx that is used to store the address
769 of the current frame into the built-in setjmp buffer. */
770 rtx (* builtin_setjmp_frame_value) (void);
772 /* This target hook should add STRING_CST trees for any hard regs
773 the port wishes to automatically clobber for an asm. */
774 tree (* md_asm_clobbers) (tree, tree, tree);
776 /* This target hook allows the backend to specify a calling convention
777 in the debug information. This function actually returns an
778 enum dwarf_calling_convention, but because of forward declarations
779 and not wanting to include dwarf2.h everywhere target.h is included
780 the function is being declared as an int. */
781 int (* dwarf_calling_convention) (const_tree);
783 /* This target hook allows the backend to emit frame-related insns that
784 contain UNSPECs or UNSPEC_VOLATILEs. The call frame debugging info
785 engine will invoke it on insns of the form
786 (set (reg) (unspec [...] UNSPEC_INDEX))
788 (set (reg) (unspec_volatile [...] UNSPECV_INDEX))
789 to let the backend emit the call frame instructions. */
790 void (* dwarf_handle_frame_unspec) (const char *, rtx, int);
792 /* Perform architecture specific checking of statements gimplified
793 from VA_ARG_EXPR. STMT is the statement. Returns true if the statement
794 doesn't need to be checked for va_list references. */
795 bool (* stdarg_optimize_hook) (struct stdarg_info *ai, const_gimple stmt);
797 /* This target hook allows the operating system to override the DECL
798 that represents the external variable that contains the stack
799 protection guard variable. The type of this DECL is ptr_type_node. */
800 tree (* stack_protect_guard) (void);
802 /* This target hook allows the operating system to override the CALL_EXPR
803 that is invoked when a check vs the guard variable fails. */
804 tree (* stack_protect_fail) (void);
806 /* Returns NULL if target supports the insn within a doloop block,
807 otherwise it returns an error message. */
808 const char * (*invalid_within_doloop) (const_rtx);
810 /* DECL is a variable or function with __attribute__((dllimport))
811 specified. Use this hook if the target needs to add extra validation
812 checks to handle_dll_attribute (). */
813 bool (* valid_dllimport_attribute_p) (const_tree decl);
815 /* Functions relating to calls - argument passing, returns, etc. */
817 bool (*promote_function_args) (const_tree fntype);
818 bool (*promote_function_return) (const_tree fntype);
819 bool (*promote_prototypes) (const_tree fntype);
820 rtx (*struct_value_rtx) (tree fndecl, int incoming);
821 bool (*return_in_memory) (const_tree type, const_tree fndecl);
822 bool (*return_in_msb) (const_tree type);
824 /* Return true if a parameter must be passed by reference. TYPE may
825 be null if this is a libcall. CA may be null if this query is
826 from __builtin_va_arg. */
827 bool (*pass_by_reference) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
828 const_tree type, bool named_arg);
830 rtx (*expand_builtin_saveregs) (void);
831 /* Returns pretend_argument_size. */
832 void (*setup_incoming_varargs) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
833 tree type, int *pretend_arg_size,
835 bool (*strict_argument_naming) (CUMULATIVE_ARGS *ca);
836 /* Returns true if we should use
837 targetm.calls.setup_incoming_varargs() and/or
838 targetm.calls.strict_argument_naming(). */
839 bool (*pretend_outgoing_varargs_named) (CUMULATIVE_ARGS *ca);
841 /* Given a complex type T, return true if a parameter of type T
842 should be passed as two scalars. */
843 bool (* split_complex_arg) (const_tree type);
845 /* Return true if type T, mode MODE, may not be passed in registers,
846 but must be passed on the stack. */
847 /* ??? This predicate should be applied strictly after pass-by-reference.
848 Need audit to verify that this is the case. */
849 bool (* must_pass_in_stack) (enum machine_mode mode, const_tree t);
851 /* Return true if type TYPE, mode MODE, which is passed by reference,
852 should have the object copy generated by the callee rather than
853 the caller. It is never called for TYPE requiring constructors. */
854 bool (* callee_copies) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
855 const_tree type, bool named);
857 /* Return zero for arguments passed entirely on the stack or entirely
858 in registers. If passed in both, return the number of bytes passed
859 in registers; the balance is therefore passed on the stack. */
860 int (* arg_partial_bytes) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
861 tree type, bool named);
863 /* Return the diagnostic message string if function without a prototype
864 is not allowed for this 'val' argument; NULL otherwise. */
865 const char *(*invalid_arg_for_unprototyped_fn) (const_tree typelist,
869 /* Return an rtx for the return value location of the function
870 specified by FN_DECL_OR_TYPE with a return type of RET_TYPE. */
871 rtx (*function_value) (const_tree ret_type, const_tree fn_decl_or_type,
874 /* Return an rtx for the argument pointer incoming to the
876 rtx (*internal_arg_pointer) (void);
878 /* Update the current function stack boundary if needed. */
879 void (*update_stack_boundary) (void);
881 /* Handle stack alignment and return an rtx for Dynamic Realign
882 Argument Pointer if necessary. */
883 rtx (*get_drap_rtx) (void);
885 /* Return true if all function parameters should be spilled to the
887 bool (*allocate_stack_slots_for_args) (void);
891 /* Return the diagnostic message string if conversion from FROMTYPE
892 to TOTYPE is not allowed, NULL otherwise. */
893 const char *(*invalid_conversion) (const_tree fromtype, const_tree totype);
895 /* Return the diagnostic message string if the unary operation OP is
896 not permitted on TYPE, NULL otherwise. */
897 const char *(*invalid_unary_op) (int op, const_tree type);
899 /* Return the diagnostic message string if the binary operation OP
900 is not permitted on TYPE1 and TYPE2, NULL otherwise. */
901 const char *(*invalid_binary_op) (int op, const_tree type1, const_tree type2);
903 /* Return the array of IRA cover classes for the current target. */
904 const enum reg_class *(*ira_cover_classes) (void);
906 /* Return the class for a secondary reload, and fill in extra information. */
907 enum reg_class (*secondary_reload) (bool, rtx, enum reg_class,
909 struct secondary_reload_info *);
911 /* This target hook allows the backend to perform additional
912 processing while initializing for variable expansion. */
913 void (* expand_to_rtl_hook) (void);
915 /* This target hook allows the backend to perform additional
916 instantiations on rtx that are not actually in insns yet,
917 but will be later. */
918 void (* instantiate_decls) (void);
920 /* Return true if is OK to use a hard register REGNO as scratch register
922 bool (* hard_regno_scratch_ok) (unsigned int regno);
924 /* Return the smallest number of different values for which it is best to
925 use a jump-table instead of a tree of conditional branches. */
926 unsigned int (* case_values_threshold) (void);
928 /* Functions specific to the C family of frontends. */
930 /* Return machine mode for non-standard suffix
931 or VOIDmode if non-standard suffixes are unsupported. */
932 enum machine_mode (*mode_for_suffix) (char);
935 /* Functions specific to the C++ frontend. */
937 /* Return the integer type used for guard variables. */
938 tree (*guard_type) (void);
939 /* Return true if only the low bit of the guard should be tested. */
940 bool (*guard_mask_bit) (void);
941 /* Returns the size of the array cookie for an array of type. */
942 tree (*get_cookie_size) (tree);
943 /* Returns true if the element size should be stored in the
945 bool (*cookie_has_size) (void);
946 /* Allows backends to perform additional processing when
947 deciding if a class should be exported or imported. */
948 int (*import_export_class) (tree, int);
949 /* Returns true if constructors and destructors return "this". */
950 bool (*cdtor_returns_this) (void);
951 /* Returns true if the key method for a class can be an inline
952 function, so long as it is not declared inline in the class
953 itself. Returning true is the behavior required by the Itanium
955 bool (*key_method_may_be_inline) (void);
956 /* DECL is a virtual table, virtual table table, typeinfo object,
957 or other similar implicit class data object that will be
958 emitted with external linkage in this translation unit. No ELF
959 visibility has been explicitly specified. If the target needs
960 to specify a visibility other than that of the containing class,
961 use this hook to set DECL_VISIBILITY and
962 DECL_VISIBILITY_SPECIFIED. */
963 void (*determine_class_data_visibility) (tree decl);
964 /* Returns true (the default) if virtual tables and other
965 similar implicit class data objects are always COMDAT if they
966 have external linkage. If this hook returns false, then
967 class data for classes whose virtual table will be emitted in
968 only one translation unit will not be COMDAT. */
969 bool (*class_data_always_comdat) (void);
970 /* Returns true (the default) if the RTTI for the basic types,
971 which is always defined in the C++ runtime, should be COMDAT;
972 false if it should not be COMDAT. */
973 bool (*library_rtti_comdat) (void);
974 /* Returns true if __aeabi_atexit should be used to register static
976 bool (*use_aeabi_atexit) (void);
977 /* Returns true if target may use atexit in the same manner as
978 __cxa_atexit to register static destructors. */
979 bool (*use_atexit_for_cxa_atexit) (void);
980 /* TYPE is a C++ class (i.e., RECORD_TYPE or UNION_TYPE) that
981 has just been defined. Use this hook to make adjustments to the
982 class (eg, tweak visibility or perform any other required
983 target modifications). */
984 void (*adjust_class_at_definition) (tree type);
987 /* Functions and data for emulated TLS support. */
989 /* Name of the address and common functions. */
990 const char *get_address;
991 const char *register_common;
993 /* Prefixes for proxy variable and template. */
994 const char *var_section;
995 const char *tmpl_section;
997 /* Prefixes for proxy variable and template. */
998 const char *var_prefix;
999 const char *tmpl_prefix;
1001 /* Function to generate field definitions of the proxy variable. */
1002 tree (*var_fields) (tree, tree *);
1004 /* Function to initialize a proxy variable. */
1005 tree (*var_init) (tree, tree, tree);
1007 /* Whether we are allowed to alter the usual alignment of the
1009 bool var_align_fixed;
1011 /* Whether we can emit debug information for TLS vars. */
1012 bool debug_form_tls_address;
1015 struct target_option_hooks {
1016 /* Function to validate the attribute((option(...))) strings or NULL. If
1017 the option is validated, it is assumed that DECL_FUNCTION_SPECIFIC will
1018 be filled in in the function decl node. */
1019 bool (*valid_attribute_p) (tree, tree, tree, int);
1021 /* Function to save any extra target state in the target options
1023 void (*save) (struct cl_target_option *);
1025 /* Function to restore any extra target state from the target options
1027 void (*restore) (struct cl_target_option *);
1029 /* Function to print any extra target state from the target options
1031 void (*print) (FILE *, int, struct cl_target_option *);
1033 /* Function to parse arguments to be validated for #pragma option, and to
1034 change the state if the options are valid. If the first argument is
1035 NULL, the second argument specifies the default options to use. Return
1036 true if the options are valid, and set the current state. */
1037 bool (*pragma_parse) (tree, tree);
1039 /* Function to determine if one function can inline another function. */
1040 bool (*can_inline_p) (tree, tree);
1043 /* For targets that need to mark extra registers as live on entry to
1044 the function, they should define this target hook and set their
1045 bits in the bitmap passed in. */
1046 void (*live_on_entry) (bitmap);
1048 /* True if unwinding tables should be generated by default. */
1049 bool unwind_tables_default;
1051 /* Leave the boolean fields at the end. */
1053 /* True if arbitrary sections are supported. */
1054 bool have_named_sections;
1056 /* True if we can create zeroed data by switching to a BSS section
1057 and then using ASM_OUTPUT_SKIP to allocate the space. */
1058 bool have_switchable_bss_sections;
1060 /* True if "native" constructors and destructors are supported,
1061 false if we're using collect2 for the job. */
1062 bool have_ctors_dtors;
1064 /* True if thread-local storage is supported. */
1067 /* True if a small readonly data section is supported. */
1068 bool have_srodata_section;
1070 /* True if EH frame info sections should be zero-terminated. */
1071 bool terminate_dw2_eh_frame_info;
1073 /* True if #NO_APP should be emitted at the beginning of
1075 bool file_start_app_off;
1077 /* True if output_file_directive should be called for main_input_filename
1078 at the beginning of assembly output. */
1079 bool file_start_file_directive;
1081 /* True if #pragma redefine_extname is to be supported. */
1082 bool handle_pragma_redefine_extname;
1084 /* True if #pragma extern_prefix is to be supported. */
1085 bool handle_pragma_extern_prefix;
1087 /* True if the target is allowed to reorder memory accesses unless
1088 synchronization is explicitly requested. */
1089 bool relaxed_ordering;
1091 /* Returns true if we should generate exception tables for use with the
1092 ARM EABI. The effects the encoding of function exception specifications.
1094 bool arm_eabi_unwinder;
1096 /* Leave the boolean fields at the end. */
1099 extern struct gcc_target targetm;
1101 struct gcc_targetcm {
1102 /* Handle target switch CODE (an OPT_* value). ARG is the argument
1103 passed to the switch; it is NULL if no argument was. VALUE is the
1104 value of ARG if CODE specifies a UInteger option, otherwise it is
1105 1 if the positive form of the switch was used and 0 if the negative
1106 form was. Return true if the switch was valid. */
1107 bool (*handle_c_option) (size_t code, const char *arg, int value);
1110 /* Each target can provide their own. */
1111 extern struct gcc_targetcm targetcm;
1113 #endif /* GCC_TARGET_H */
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