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1 /* Data structure definitions for a generic GCC target.
2 Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
3 Free Software Foundation, Inc.
4
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
8 later version.
9
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.
14
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/>.
18
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! */
22
23
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
27 information.
28
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
31 macros.
32
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
38 "targetm" like so:
39
40 struct gcc_target targetm = TARGET_INITIALIZER;
41
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. */
48
49 #ifndef GCC_TARGET_H
50 #define GCC_TARGET_H
51
52 #include "tm.h"
53 #include "insn-modes.h"
54
55 /* Types used by the record_gcc_switches() target function. */
56 typedef enum
57 {
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. */
63 }
64 print_switch_type;
65
66 typedef int (* print_switch_fn_type) (print_switch_type, const char *);
67
68 /* An example implementation for ELF targets. Defined in varasm.c */
69 extern int elf_record_gcc_switches (print_switch_type type, const char *);
70
71 /* Some places still assume that all pointer or address modes are the
72 standard Pmode and ptr_mode. These optimizations become invalid if
73 the target actually supports multiple different modes. For now,
74 we disable such optimizations on such targets, using this function. */
75 extern bool target_default_pointer_address_modes_p (void);
76
77 struct stdarg_info;
78 struct spec_info_def;
79
80 /* The struct used by the secondary_reload target hook. */
81 typedef struct secondary_reload_info
82 {
83 /* icode is actually an enum insn_code, but we don't want to force every
84 file that includes target.h to include optabs.h . */
85 int icode;
86 int extra_cost; /* Cost for using (a) scratch register(s) to be taken
87 into account by copy_cost. */
88 /* The next two members are for the use of the backward
89 compatibility hook. */
90 struct secondary_reload_info *prev_sri;
91 int t_icode; /* Actually an enum insn_code - see above. */
92 } secondary_reload_info;
93
94 /* This is defined in sched-int.h . */
95 struct _dep;
96
97 /* This is defined in ddg.h . */
98 struct ddg;
99
100 /* This is defined in cfgloop.h . */
101 struct loop;
102
103 /* Assembler instructions for creating various kinds of integer object. */
104
105 struct asm_int_op
106 {
107 const char *hi;
108 const char *si;
109 const char *di;
110 const char *ti;
111 };
112
113 /* The target structure. This holds all the backend hooks. */
114
115 struct gcc_target
116 {
117 /* Functions that output assembler for the target. */
118 struct asm_out
119 {
120 /* Opening and closing parentheses for asm expression grouping. */
121 const char *open_paren, *close_paren;
122
123 /* Assembler instructions for creating various kinds of integer object. */
124 const char *byte_op;
125 struct asm_int_op aligned_op, unaligned_op;
126
127 /* Try to output the assembler code for an integer object whose
128 value is given by X. SIZE is the size of the object in bytes and
129 ALIGNED_P indicates whether it is aligned. Return true if
130 successful. Only handles cases for which BYTE_OP, ALIGNED_OP
131 and UNALIGNED_OP are NULL. */
132 bool (* integer) (rtx x, unsigned int size, int aligned_p);
133
134 /* Output code that will globalize a label. */
135 void (* globalize_label) (FILE *, const char *);
136
137 /* Output code that will globalize a declaration. */
138 void (* globalize_decl_name) (FILE *, tree);
139
140 /* Output code that will emit a label for unwind info, if this
141 target requires such labels. Second argument is the decl the
142 unwind info is associated with, third is a boolean: true if
143 this is for exception handling, fourth is a boolean: true if
144 this is only a placeholder for an omitted FDE. */
145 void (* unwind_label) (FILE *, tree, int, int);
146
147 /* Output code that will emit a label to divide up the exception
148 table. */
149 void (* except_table_label) (FILE *);
150
151 /* Emit any directives required to unwind this instruction. */
152 void (* unwind_emit) (FILE *, rtx);
153
154 /* Output an internal label. */
155 void (* internal_label) (FILE *, const char *, unsigned long);
156
157 /* Emit a ttype table reference to a typeinfo object. */
158 bool (* ttype) (rtx);
159
160 /* Emit an assembler directive to set visibility for the symbol
161 associated with the tree decl. */
162 void (* visibility) (tree, int);
163
164 /* Output the assembler code for entry to a function. */
165 void (* function_prologue) (FILE *, HOST_WIDE_INT);
166
167 /* Output the assembler code for end of prologue. */
168 void (* function_end_prologue) (FILE *);
169
170 /* Output the assembler code for start of epilogue. */
171 void (* function_begin_epilogue) (FILE *);
172
173 /* Output the assembler code for function exit. */
174 void (* function_epilogue) (FILE *, HOST_WIDE_INT);
175
176 /* Initialize target-specific sections. */
177 void (* init_sections) (void);
178
179 /* Tell assembler to change to section NAME with attributes FLAGS.
180 If DECL is non-NULL, it is the VAR_DECL or FUNCTION_DECL with
181 which this section is associated. */
182 void (* named_section) (const char *name, unsigned int flags, tree decl);
183
184 /* Return a mask describing how relocations should be treated when
185 selecting sections. Bit 1 should be set if global relocations
186 should be placed in a read-write section; bit 0 should be set if
187 local relocations should be placed in a read-write section. */
188 int (*reloc_rw_mask) (void);
189
190 /* Return a section for EXP. It may be a DECL or a constant. RELOC
191 is nonzero if runtime relocations must be applied; bit 1 will be
192 set if the runtime relocations require non-local name resolution.
193 ALIGN is the required alignment of the data. */
194 section *(* select_section) (tree, int, unsigned HOST_WIDE_INT);
195
196 /* Return a section for X. MODE is X's mode and ALIGN is its
197 alignment in bits. */
198 section *(* select_rtx_section) (enum machine_mode, rtx,
199 unsigned HOST_WIDE_INT);
200
201 /* Select a unique section name for DECL. RELOC is the same as
202 for SELECT_SECTION. */
203 void (* unique_section) (tree, int);
204
205 /* Return the readonly data section associated with function DECL. */
206 section *(* function_rodata_section) (tree);
207
208 /* Output a constructor for a symbol with a given priority. */
209 void (* constructor) (rtx, int);
210
211 /* Output a destructor for a symbol with a given priority. */
212 void (* destructor) (rtx, int);
213
214 /* Output the assembler code for a thunk function. THUNK_DECL is the
215 declaration for the thunk function itself, FUNCTION is the decl for
216 the target function. DELTA is an immediate constant offset to be
217 added to THIS. If VCALL_OFFSET is nonzero, the word at
218 *(*this + vcall_offset) should be added to THIS. */
219 void (* output_mi_thunk) (FILE *file, tree thunk_decl,
220 HOST_WIDE_INT delta, HOST_WIDE_INT vcall_offset,
221 tree function_decl);
222
223 /* Determine whether output_mi_thunk would succeed. */
224 /* ??? Ideally, this hook would not exist, and success or failure
225 would be returned from output_mi_thunk directly. But there's
226 too much undo-able setup involved in invoking output_mi_thunk.
227 Could be fixed by making output_mi_thunk emit rtl instead of
228 text to the output file. */
229 bool (* can_output_mi_thunk) (const_tree thunk_decl, HOST_WIDE_INT delta,
230 HOST_WIDE_INT vcall_offset,
231 const_tree function_decl);
232
233 /* Output any boilerplate text needed at the beginning of a
234 translation unit. */
235 void (*file_start) (void);
236
237 /* Output any boilerplate text needed at the end of a
238 translation unit. */
239 void (*file_end) (void);
240
241 /* Output any boilerplate text needed at the beginning of an
242 LTO output stream. */
243 void (*lto_start) (void);
244
245 /* Output any boilerplate text needed at the end of an
246 LTO output stream. */
247 void (*lto_end) (void);
248
249 /* Output any boilerplace text needed at the end of a
250 translation unit before debug and unwind info is emitted. */
251 void (*code_end) (void);
252
253 /* Output an assembler pseudo-op to declare a library function name
254 external. */
255 void (*external_libcall) (rtx);
256
257 /* Output an assembler directive to mark decl live. This instructs
258 linker to not dead code strip this symbol. */
259 void (*mark_decl_preserved) (const char *);
260
261 /* Output a record of the command line switches that have been passed. */
262 print_switch_fn_type record_gcc_switches;
263 /* The name of the section that the example ELF implementation of
264 record_gcc_switches will use to store the information. Target
265 specific versions of record_gcc_switches may or may not use
266 this information. */
267 const char * record_gcc_switches_section;
268
269 /* Output the definition of a section anchor. */
270 void (*output_anchor) (rtx);
271
272 /* Output a DTP-relative reference to a TLS symbol. */
273 void (*output_dwarf_dtprel) (FILE *file, int size, rtx x);
274
275 /* Some target machines need to postscan each insn after it is output. */
276 void (*final_postscan_insn) (FILE *, rtx, rtx *, int);
277
278 /* Emit the trampoline template. This hook may be NULL. */
279 void (*trampoline_template) (FILE *);
280 } asm_out;
281
282 /* Functions relating to instruction scheduling. */
283 struct sched
284 {
285 /* Given the current cost, COST, of an insn, INSN, calculate and
286 return a new cost based on its relationship to DEP_INSN through
287 the dependence LINK. The default is to make no adjustment. */
288 int (* adjust_cost) (rtx insn, rtx link, rtx dep_insn, int cost);
289
290 /* Adjust the priority of an insn as you see fit. Returns the new
291 priority. */
292 int (* adjust_priority) (rtx, int);
293
294 /* Function which returns the maximum number of insns that can be
295 scheduled in the same machine cycle. This must be constant
296 over an entire compilation. The default is 1. */
297 int (* issue_rate) (void);
298
299 /* Calculate how much this insn affects how many more insns we
300 can emit this cycle. Default is they all cost the same. */
301 int (* variable_issue) (FILE *, int, rtx, int);
302
303 /* Initialize machine-dependent scheduling code. */
304 void (* md_init) (FILE *, int, int);
305
306 /* Finalize machine-dependent scheduling code. */
307 void (* md_finish) (FILE *, int);
308
309 /* Initialize machine-dependent function wide scheduling code. */
310 void (* md_init_global) (FILE *, int, int);
311
312 /* Finalize machine-dependent function wide scheduling code. */
313 void (* md_finish_global) (FILE *, int);
314
315 /* Reorder insns in a machine-dependent fashion, in two different
316 places. Default does nothing. */
317 int (* reorder) (FILE *, int, rtx *, int *, int);
318 int (* reorder2) (FILE *, int, rtx *, int *, int);
319
320 /* The following member value is a pointer to a function called
321 after evaluation forward dependencies of insns in chain given
322 by two parameter values (head and tail correspondingly). */
323 void (* dependencies_evaluation_hook) (rtx, rtx);
324
325 /* The values of the following four members are pointers to
326 functions used to simplify the automaton descriptions.
327 dfa_pre_cycle_insn and dfa_post_cycle_insn give functions
328 returning insns which are used to change the pipeline hazard
329 recognizer state when the new simulated processor cycle
330 correspondingly starts and finishes. The function defined by
331 init_dfa_pre_cycle_insn and init_dfa_post_cycle_insn are used
332 to initialize the corresponding insns. The default values of
333 the members result in not changing the automaton state when
334 the new simulated processor cycle correspondingly starts and
335 finishes. */
336 void (* init_dfa_pre_cycle_insn) (void);
337 rtx (* dfa_pre_cycle_insn) (void);
338 void (* init_dfa_post_cycle_insn) (void);
339 rtx (* dfa_post_cycle_insn) (void);
340
341 /* The values of the following two members are pointers to
342 functions used to simplify the automaton descriptions.
343 dfa_pre_advance_cycle and dfa_post_advance_cycle are getting called
344 immediately before and after cycle is advanced. */
345 void (* dfa_pre_advance_cycle) (void);
346 void (* dfa_post_advance_cycle) (void);
347
348 /* The following member value is a pointer to a function returning value
349 which defines how many insns in queue `ready' will we try for
350 multi-pass scheduling. If the member value is nonzero and the
351 function returns positive value, the DFA based scheduler will make
352 multi-pass scheduling for the first cycle. In other words, we will
353 try to choose ready insn which permits to start maximum number of
354 insns on the same cycle. */
355 int (* first_cycle_multipass_dfa_lookahead) (void);
356
357 /* The following member value is pointer to a function controlling
358 what insns from the ready insn queue will be considered for the
359 multipass insn scheduling. If the hook returns zero for insn
360 passed as the parameter, the insn will be not chosen to be
361 issued. */
362 int (* first_cycle_multipass_dfa_lookahead_guard) (rtx);
363
364 /* The following member value is pointer to a function called by
365 the insn scheduler before issuing insn passed as the third
366 parameter on given cycle. If the hook returns nonzero, the
367 insn is not issued on given processors cycle. Instead of that,
368 the processor cycle is advanced. If the value passed through
369 the last parameter is zero, the insn ready queue is not sorted
370 on the new cycle start as usually. The first parameter passes
371 file for debugging output. The second one passes the scheduler
372 verbose level of the debugging output. The forth and the fifth
373 parameter values are correspondingly processor cycle on which
374 the previous insn has been issued and the current processor
375 cycle. */
376 int (* dfa_new_cycle) (FILE *, int, rtx, int, int, int *);
377
378 /* The following member value is a pointer to a function called by the
379 insn scheduler. It should return true if there exists a dependence
380 which is considered costly by the target, between the insn
381 DEP_PRO (&_DEP), and the insn DEP_CON (&_DEP). The first parameter is
382 the dep that represents the dependence between the two insns. The
383 second argument is the cost of the dependence as estimated by
384 the scheduler. The last argument is the distance in cycles
385 between the already scheduled insn (first parameter) and the
386 second insn (second parameter). */
387 bool (* is_costly_dependence) (struct _dep *_dep, int, int);
388
389 /* Given the current cost, COST, of an insn, INSN, calculate and
390 return a new cost based on its relationship to DEP_INSN through the
391 dependence of type DEP_TYPE. The default is to make no adjustment. */
392 int (* adjust_cost_2) (rtx insn, int, rtx dep_insn, int cost, int dw);
393
394 /* The following member value is a pointer to a function called
395 by the insn scheduler. This hook is called to notify the backend
396 that new instructions were emitted. */
397 void (* h_i_d_extended) (void);
398
399 /* Next 5 functions are for multi-point scheduling. */
400
401 /* Allocate memory for scheduler context. */
402 void *(* alloc_sched_context) (void);
403
404 /* Fills the context from the local machine scheduler context. */
405 void (* init_sched_context) (void *, bool);
406
407 /* Sets local machine scheduler context to a saved value. */
408 void (* set_sched_context) (void *);
409
410 /* Clears a scheduler context so it becomes like after init. */
411 void (* clear_sched_context) (void *);
412
413 /* Frees the scheduler context. */
414 void (* free_sched_context) (void *);
415
416 /* The following member value is a pointer to a function called
417 by the insn scheduler.
418 The first parameter is an instruction, the second parameter is the type
419 of the requested speculation, and the third parameter is a pointer to the
420 speculative pattern of the corresponding type (set if return value == 1).
421 It should return
422 -1, if there is no pattern, that will satisfy the requested speculation
423 type,
424 0, if current pattern satisfies the requested speculation type,
425 1, if pattern of the instruction should be changed to the newly
426 generated one. */
427 int (* speculate_insn) (rtx, int, rtx *);
428
429 /* The following member value is a pointer to a function called
430 by the insn scheduler. It should return true if the check instruction
431 passed as the parameter needs a recovery block. */
432 bool (* needs_block_p) (int);
433
434 /* The following member value is a pointer to a function called
435 by the insn scheduler. It should return a pattern for the check
436 instruction.
437 The first parameter is a speculative instruction, the second parameter
438 is the label of the corresponding recovery block (or null, if it is a
439 simple check). If the mutation of the check is requested (e.g. from
440 ld.c to chk.a), the third parameter is true - in this case the first
441 parameter is the previous check. */
442 rtx (* gen_spec_check) (rtx, rtx, int);
443
444 /* The following member value is a pointer to a function controlling
445 what insns from the ready insn queue will be considered for the
446 multipass insn scheduling. If the hook returns zero for the insn
447 passed as the parameter, the insn will not be chosen to be
448 issued. This hook is used to discard speculative instructions,
449 that stand at the first position of the ready list. */
450 bool (* first_cycle_multipass_dfa_lookahead_guard_spec) (const_rtx);
451
452 /* The following member value is a pointer to a function that provides
453 information about the speculation capabilities of the target.
454 The parameter is a pointer to spec_info variable. */
455 void (* set_sched_flags) (struct spec_info_def *);
456
457 /* Return speculation types of the instruction passed as the parameter. */
458 int (* get_insn_spec_ds) (rtx);
459
460 /* Return speculation types that are checked for the instruction passed as
461 the parameter. */
462 int (* get_insn_checked_ds) (rtx);
463
464 /* Return bool if rtx scanning should just skip current layer and
465 advance to the inner rtxes. */
466 bool (* skip_rtx_p) (const_rtx);
467
468 /* The following member value is a pointer to a function that provides
469 information about the target resource-based lower bound which is
470 used by the swing modulo scheduler. The parameter is a pointer
471 to ddg variable. */
472 int (* sms_res_mii) (struct ddg *);
473 } sched;
474
475 /* Functions relating to vectorization. */
476 struct vectorize
477 {
478 /* The following member value is a pointer to a function called
479 by the vectorizer, and return the decl of the target builtin
480 function. */
481 tree (* builtin_mask_for_load) (void);
482
483 /* Returns a code for builtin that realizes vectorized version of
484 function, or NULL_TREE if not available. */
485 tree (* builtin_vectorized_function) (tree, tree, tree);
486
487 /* Returns a function declaration for a builtin that realizes the
488 vector conversion, or NULL_TREE if not available. */
489 tree (* builtin_conversion) (unsigned, tree, tree);
490
491 /* Target builtin that implements vector widening multiplication.
492 builtin_mul_widen_eve computes the element-by-element products
493 for the even elements, and builtin_mul_widen_odd computes the
494 element-by-element products for the odd elements. */
495 tree (* builtin_mul_widen_even) (tree);
496 tree (* builtin_mul_widen_odd) (tree);
497
498 /* Returns the cost to be added to the overheads involved with
499 executing the vectorized version of a loop. */
500 int (*builtin_vectorization_cost) (bool);
501
502 /* Return true if vector alignment is reachable (by peeling N
503 iterations) for the given type. */
504 bool (* vector_alignment_reachable) (const_tree, bool);
505
506 /* Target builtin that implements vector permute. */
507 tree (* builtin_vec_perm) (tree, tree*);
508
509 /* Return true if a vector created for builtin_vec_perm is valid. */
510 bool (* builtin_vec_perm_ok) (tree, tree);
511
512 /* Return true if the target supports misaligned store/load of a
513 specific factor denoted in the third parameter. The last parameter
514 is true if the access is defined in a packed struct. */
515 bool (* builtin_support_vector_misalignment) (enum machine_mode,
516 const_tree, int, bool);
517 } vectorize;
518
519 /* The initial value of target_flags. */
520 int default_target_flags;
521
522 /* Allow target specific overriding of option settings after options have
523 been changed by an attribute or pragma or when it is reset at the
524 end of the code affected by an attribute or pragma. */
525 void (* override_options_after_change) (void);
526
527 /* Handle target switch CODE (an OPT_* value). ARG is the argument
528 passed to the switch; it is NULL if no argument was. VALUE is the
529 value of ARG if CODE specifies a UInteger option, otherwise it is
530 1 if the positive form of the switch was used and 0 if the negative
531 form was. Return true if the switch was valid. */
532 bool (* handle_option) (size_t code, const char *arg, int value);
533
534 /* Handle target-specific parts of specifying -Ofast. */
535 void (* handle_ofast) (void);
536
537 /* Display extra, target specific information in response to a
538 --target-help switch. */
539 void (* target_help) (void);
540
541 /* Return machine mode for filter value. */
542 enum machine_mode (* eh_return_filter_mode) (void);
543
544 /* Return machine mode for libgcc expanded cmp instructions. */
545 enum machine_mode (* libgcc_cmp_return_mode) (void);
546
547 /* Return machine mode for libgcc expanded shift instructions. */
548 enum machine_mode (* libgcc_shift_count_mode) (void);
549
550 /* Return machine mode to be used for _Unwind_Word type. */
551 enum machine_mode (* unwind_word_mode) (void);
552
553 /* Given two decls, merge their attributes and return the result. */
554 tree (* merge_decl_attributes) (tree, tree);
555
556 /* Given two types, merge their attributes and return the result. */
557 tree (* merge_type_attributes) (tree, tree);
558
559 /* Table of machine attributes and functions to handle them.
560 Ignored if NULL. */
561 const struct attribute_spec *attribute_table;
562
563 /* Return true iff attribute NAME expects a plain identifier as its first
564 argument. */
565 bool (*attribute_takes_identifier_p) (const_tree name);
566
567 /* Return zero if the attributes on TYPE1 and TYPE2 are incompatible,
568 one if they are compatible and two if they are nearly compatible
569 (which causes a warning to be generated). */
570 int (* comp_type_attributes) (const_tree type1, const_tree type2);
571
572 /* Assign default attributes to the newly defined TYPE. */
573 void (* set_default_type_attributes) (tree type);
574
575 /* Insert attributes on the newly created DECL. */
576 void (* insert_attributes) (tree decl, tree *attributes);
577
578 /* Return true if FNDECL (which has at least one machine attribute)
579 can be inlined despite its machine attributes, false otherwise. */
580 bool (* function_attribute_inlinable_p) (const_tree fndecl);
581
582 /* Return true if bitfields in RECORD_TYPE should follow the
583 Microsoft Visual C++ bitfield layout rules. */
584 bool (* ms_bitfield_layout_p) (const_tree record_type);
585
586 /* True if the target supports decimal floating point. */
587 bool (* decimal_float_supported_p) (void);
588
589 /* True if the target supports fixed-point. */
590 bool (* fixed_point_supported_p) (void);
591
592 /* Return true if anonymous bitfields affect structure alignment. */
593 bool (* align_anon_bitfield) (void);
594
595 /* Return true if volatile bitfields should use the narrowest type possible.
596 Return false if they should use the container type. */
597 bool (* narrow_volatile_bitfield) (void);
598
599 /* Set up target-specific built-in functions. */
600 void (* init_builtins) (void);
601
602 /* Initialize (if INITIALIZE_P is true) and return the target-specific
603 built-in function decl for CODE.
604 Return NULL if that is not possible. Return error_mark_node if CODE
605 is outside of the range of valid target builtin function codes. */
606 tree (* builtin_decl) (unsigned code, bool initialize_p);
607
608 /* Expand a target-specific builtin. */
609 rtx (* expand_builtin) (tree exp, rtx target, rtx subtarget,
610 enum machine_mode mode, int ignore);
611
612 /* Select a replacement for a target-specific builtin. This is done
613 *before* regular type checking, and so allows the target to
614 implement a crude form of function overloading. The result is a
615 complete expression that implements the operation. PARAMS really
616 has type VEC(tree,gc)*, but we don't want to include tree.h
617 here. */
618 tree (*resolve_overloaded_builtin) (unsigned int /*location_t*/,
619 tree decl, void *params);
620
621 /* Fold a target-specific builtin. */
622 tree (* fold_builtin) (tree fndecl, int nargs, tree *argp, bool ignore);
623
624 /* Returns a code for a target-specific builtin that implements
625 reciprocal of the function, or NULL_TREE if not available. */
626 tree (* builtin_reciprocal) (unsigned, bool, bool);
627
628 /* For a vendor-specific TYPE, return a pointer to a statically-allocated
629 string containing the C++ mangling for TYPE. In all other cases, return
630 NULL. */
631 const char * (* mangle_type) (const_tree type);
632
633 /* Make any adjustments to libfunc names needed for this target. */
634 void (* init_libfuncs) (void);
635
636 /* Given a decl, a section name, and whether the decl initializer
637 has relocs, choose attributes for the section. */
638 /* ??? Should be merged with SELECT_SECTION and UNIQUE_SECTION. */
639 unsigned int (* section_type_flags) (tree, const char *, int);
640
641 /* True if new jumps cannot be created, to replace existing ones or
642 not, at the current point in the compilation. */
643 bool (* cannot_modify_jumps_p) (void);
644
645 /* Return a register class for which branch target register
646 optimizations should be applied. */
647 enum reg_class (* branch_target_register_class) (void);
648
649 /* Return true if branch target register optimizations should include
650 callee-saved registers that are not already live during the current
651 function. AFTER_PE_GEN is true if prologues and epilogues have
652 already been generated. */
653 bool (* branch_target_register_callee_saved) (bool after_pe_gen);
654
655 /* Return true if the target supports conditional execution. */
656 bool (* have_conditional_execution) (void);
657
658 /* Return a new value for loop unroll size. */
659 unsigned (* loop_unroll_adjust) (unsigned nunroll, struct loop *loop);
660
661 /* True if the constant X cannot be placed in the constant pool. */
662 bool (* cannot_force_const_mem) (rtx);
663
664 /* True if the insn X cannot be duplicated. */
665 bool (* cannot_copy_insn_p) (rtx);
666
667 /* True if X is considered to be commutative. */
668 bool (* commutative_p) (const_rtx, int);
669
670 /* True if ADDR is an address-expression whose effect depends
671 on the mode of the memory reference it is used in. */
672 bool (* mode_dependent_address_p) (const_rtx addr);
673
674 /* Given an invalid address X for a given machine mode, try machine-specific
675 ways to make it legitimate. Return X or an invalid address on failure. */
676 rtx (* legitimize_address) (rtx, rtx, enum machine_mode);
677
678 /* Given an address RTX, undo the effects of LEGITIMIZE_ADDRESS. */
679 rtx (* delegitimize_address) (rtx);
680
681 /* Given an address RTX, say whether it is valid. */
682 bool (* legitimate_address_p) (enum machine_mode, rtx, bool);
683
684 /* True if the given constant can be put into an object_block. */
685 bool (* use_blocks_for_constant_p) (enum machine_mode, const_rtx);
686
687 /* The minimum and maximum byte offsets for anchored addresses. */
688 HOST_WIDE_INT min_anchor_offset;
689 HOST_WIDE_INT max_anchor_offset;
690
691 /* True if section anchors can be used to access the given symbol. */
692 bool (* use_anchors_for_symbol_p) (const_rtx);
693
694 /* True if it is OK to do sibling call optimization for the specified
695 call expression EXP. DECL will be the called function, or NULL if
696 this is an indirect call. */
697 bool (*function_ok_for_sibcall) (tree decl, tree exp);
698
699 /* Establish appropriate back-end context for processing the function
700 FNDECL. The argument might be NULL to indicate processing at top
701 level, outside of any function scope. */
702 void (*set_current_function) (tree fndecl);
703
704 /* True if EXP should be placed in a "small data" section. */
705 bool (* in_small_data_p) (const_tree);
706
707 /* True if EXP names an object for which name resolution must resolve
708 to the current executable or shared library. */
709 bool (* binds_local_p) (const_tree);
710
711 /* Modify and return the identifier of a DECL's external name,
712 originally identified by ID, as required by the target,
713 (eg, append @nn to windows32 stdcall function names).
714 The default is to return ID without modification. */
715 tree (* mangle_decl_assembler_name) (tree decl, tree id);
716
717 /* Do something target-specific to record properties of the DECL into
718 the associated SYMBOL_REF. */
719 void (* encode_section_info) (tree, rtx, int);
720
721 /* Undo the effects of encode_section_info on the symbol string. */
722 const char * (* strip_name_encoding) (const char *);
723
724 /* If shift optabs for MODE are known to always truncate the shift count,
725 return the mask that they apply. Return 0 otherwise. */
726 unsigned HOST_WIDE_INT (* shift_truncation_mask) (enum machine_mode mode);
727
728 /* Return the number of divisions in the given MODE that should be present,
729 so that it is profitable to turn the division into a multiplication by
730 the reciprocal. */
731 unsigned int (* min_divisions_for_recip_mul) (enum machine_mode mode);
732
733 /* If the representation of integral MODE is such that values are
734 always sign-extended to a wider mode MODE_REP then return
735 SIGN_EXTEND. Return UNKNOWN otherwise. */
736 /* Note that the return type ought to be RTX_CODE, but that's not
737 necessarily defined at this point. */
738 int (* mode_rep_extended) (enum machine_mode mode,
739 enum machine_mode mode_rep);
740
741 /* True if MODE is valid for a pointer in __attribute__((mode("MODE"))). */
742 bool (* valid_pointer_mode) (enum machine_mode mode);
743
744 /* Support for named address spaces. */
745 struct addr_space {
746 /* MODE to use for a pointer into another address space. */
747 enum machine_mode (* pointer_mode) (addr_space_t);
748
749 /* MODE to use for an address in another address space. */
750 enum machine_mode (* address_mode) (addr_space_t);
751
752 /* True if MODE is valid for a pointer in __attribute__((mode("MODE")))
753 in another address space. */
754 bool (* valid_pointer_mode) (enum machine_mode, addr_space_t);
755
756 /* True if an address is a valid memory address to a given named address
757 space for a given mode. */
758 bool (* legitimate_address_p) (enum machine_mode, rtx, bool, addr_space_t);
759
760 /* Return an updated address to convert an invalid pointer to a named
761 address space to a valid one. If NULL_RTX is returned use machine
762 independent methods to make the address valid. */
763 rtx (* legitimize_address) (rtx, rtx, enum machine_mode, addr_space_t);
764
765 /* True if one named address space is a subset of another named address. */
766 bool (* subset_p) (addr_space_t, addr_space_t);
767
768 /* Function to convert an rtl expression from one address space to
769 another. */
770 rtx (* convert) (rtx, tree, tree);
771
772 } addr_space;
773
774 /* True if MODE is valid for the target. By "valid", we mean able to
775 be manipulated in non-trivial ways. In particular, this means all
776 the arithmetic is supported. */
777 bool (* scalar_mode_supported_p) (enum machine_mode mode);
778
779 /* Similarly for vector modes. "Supported" here is less strict. At
780 least some operations are supported; need to check optabs or builtins
781 for further details. */
782 bool (* vector_mode_supported_p) (enum machine_mode mode);
783
784 /* True for MODE if the target expects that registers in this mode will
785 be allocated to registers in a small register class. The compiler is
786 allowed to use registers explicitly used in the rtl as spill registers
787 but it should prevent extending the lifetime of these registers. */
788 bool (* small_register_classes_for_mode_p) (enum machine_mode mode);
789
790 /* Compute a (partial) cost for rtx X. Return true if the complete
791 cost has been computed, and false if subexpressions should be
792 scanned. In either case, *TOTAL contains the cost result. */
793 /* Note that CODE and OUTER_CODE ought to be RTX_CODE, but that's
794 not necessarily defined at this point. */
795 bool (* rtx_costs) (rtx x, int code, int outer_code, int *total, bool speed);
796
797 /* Compute the cost of X, used as an address. Never called with
798 invalid addresses. */
799 int (* address_cost) (rtx x, bool speed);
800
801 /* Return where to allocate pseudo for a given hard register initial
802 value. */
803 rtx (* allocate_initial_value) (rtx x);
804
805 /* Return nonzero if evaluating UNSPEC[_VOLATILE] X might cause a trap.
806 FLAGS has the same meaning as in rtlanal.c: may_trap_p_1. */
807 int (* unspec_may_trap_p) (const_rtx x, unsigned flags);
808
809 /* Given a register, this hook should return a parallel of registers
810 to represent where to find the register pieces. Define this hook
811 if the register and its mode are represented in Dwarf in
812 non-contiguous locations, or if the register should be
813 represented in more than one register in Dwarf. Otherwise, this
814 hook should return NULL_RTX. */
815 rtx (* dwarf_register_span) (rtx);
816
817 /* If expand_builtin_init_dwarf_reg_sizes needs to fill in table
818 entries not corresponding directly to registers below
819 FIRST_PSEUDO_REGISTER, this hook should generate the necessary
820 code, given the address of the table. */
821 void (* init_dwarf_reg_sizes_extra) (tree);
822
823 /* Fetch the fixed register(s) which hold condition codes, for
824 targets where it makes sense to look for duplicate assignments to
825 the condition codes. This should return true if there is such a
826 register, false otherwise. The arguments should be set to the
827 fixed register numbers. Up to two condition code registers are
828 supported. If there is only one for this target, the int pointed
829 at by the second argument should be set to -1. */
830 bool (* fixed_condition_code_regs) (unsigned int *, unsigned int *);
831
832 /* If two condition code modes are compatible, return a condition
833 code mode which is compatible with both, such that a comparison
834 done in the returned mode will work for both of the original
835 modes. If the condition code modes are not compatible, return
836 VOIDmode. */
837 enum machine_mode (* cc_modes_compatible) (enum machine_mode,
838 enum machine_mode);
839
840 /* Do machine-dependent code transformations. Called just before
841 delayed-branch scheduling. */
842 void (* machine_dependent_reorg) (void);
843
844 /* Create the __builtin_va_list type. */
845 tree (* build_builtin_va_list) (void);
846
847 /* Get the cfun/fndecl calling abi __builtin_va_list type. */
848 tree (* fn_abi_va_list) (tree);
849
850 /* Get the __builtin_va_list type dependent on input type. */
851 tree (* canonical_va_list_type) (tree);
852
853 /* Expand the __builtin_va_start builtin. */
854 void (* expand_builtin_va_start) (tree valist, rtx nextarg);
855
856 /* Gimplifies a VA_ARG_EXPR. */
857 tree (* gimplify_va_arg_expr) (tree valist, tree type, gimple_seq *pre_p,
858 gimple_seq *post_p);
859
860 /* Validity-checking routines for PCH files, target-specific.
861 get_pch_validity returns a pointer to the data to be stored,
862 and stores the size in its argument. pch_valid_p gets the same
863 information back and returns NULL if the PCH is valid,
864 or an error message if not.
865 */
866 void * (* get_pch_validity) (size_t *);
867 const char * (* pch_valid_p) (const void *, size_t);
868
869 /* If nonnull, this function checks whether a PCH file with the
870 given set of target flags can be used. It returns NULL if so,
871 otherwise it returns an error message. */
872 const char *(*check_pch_target_flags) (int);
873
874 /* True if the compiler should give an enum type only as many
875 bytes as it takes to represent the range of possible values of
876 that type. */
877 bool (* default_short_enums) (void);
878
879 /* This target hook returns an rtx that is used to store the address
880 of the current frame into the built-in setjmp buffer. */
881 rtx (* builtin_setjmp_frame_value) (void);
882
883 /* This target hook should add STRING_CST trees for any hard regs
884 the port wishes to automatically clobber for an asm. */
885 tree (* md_asm_clobbers) (tree, tree, tree);
886
887 /* This target hook allows the backend to specify a calling convention
888 in the debug information. This function actually returns an
889 enum dwarf_calling_convention, but because of forward declarations
890 and not wanting to include dwarf2.h everywhere target.h is included
891 the function is being declared as an int. */
892 int (* dwarf_calling_convention) (const_tree);
893
894 /* This target hook allows the backend to emit frame-related insns that
895 contain UNSPECs or UNSPEC_VOLATILEs. The call frame debugging info
896 engine will invoke it on insns of the form
897 (set (reg) (unspec [...] UNSPEC_INDEX))
898 and
899 (set (reg) (unspec_volatile [...] UNSPECV_INDEX))
900 to let the backend emit the call frame instructions. */
901 void (* dwarf_handle_frame_unspec) (const char *, rtx, int);
902
903 /* Perform architecture specific checking of statements gimplified
904 from VA_ARG_EXPR. STMT is the statement. Returns true if the statement
905 doesn't need to be checked for va_list references. */
906 bool (* stdarg_optimize_hook) (struct stdarg_info *ai, const_gimple stmt);
907
908 /* This target hook allows the operating system to override the DECL
909 that represents the external variable that contains the stack
910 protection guard variable. The type of this DECL is ptr_type_node. */
911 tree (* stack_protect_guard) (void);
912
913 /* This target hook allows the operating system to override the CALL_EXPR
914 that is invoked when a check vs the guard variable fails. */
915 tree (* stack_protect_fail) (void);
916
917 /* Returns NULL if target supports the insn within a doloop block,
918 otherwise it returns an error message. */
919 const char * (*invalid_within_doloop) (const_rtx);
920
921 /* DECL is a variable or function with __attribute__((dllimport))
922 specified. Use this hook if the target needs to add extra validation
923 checks to handle_dll_attribute (). */
924 bool (* valid_dllimport_attribute_p) (const_tree decl);
925
926 /* If non-zero, align constant anchors in CSE to a multiple of this
927 value. */
928 unsigned HOST_WIDE_INT const_anchor;
929
930 /* Functions relating to calls - argument passing, returns, etc. */
931 struct calls {
932 enum machine_mode (*promote_function_mode) (const_tree type,
933 enum machine_mode mode,
934 int *punsignedp,
935 const_tree fntype,
936 int for_return);
937 bool (*promote_prototypes) (const_tree fntype);
938 rtx (*struct_value_rtx) (tree fndecl, int incoming);
939 bool (*return_in_memory) (const_tree type, const_tree fndecl);
940 bool (*return_in_msb) (const_tree type);
941
942 /* Return true if a parameter must be passed by reference. TYPE may
943 be null if this is a libcall. CA may be null if this query is
944 from __builtin_va_arg. */
945 bool (*pass_by_reference) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
946 const_tree type, bool named_arg);
947
948 rtx (*expand_builtin_saveregs) (void);
949 /* Returns pretend_argument_size. */
950 void (*setup_incoming_varargs) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
951 tree type, int *pretend_arg_size,
952 int second_time);
953 bool (*strict_argument_naming) (CUMULATIVE_ARGS *ca);
954 /* Returns true if we should use
955 targetm.calls.setup_incoming_varargs() and/or
956 targetm.calls.strict_argument_naming(). */
957 bool (*pretend_outgoing_varargs_named) (CUMULATIVE_ARGS *ca);
958
959 /* Given a complex type T, return true if a parameter of type T
960 should be passed as two scalars. */
961 bool (* split_complex_arg) (const_tree type);
962
963 /* Return true if type T, mode MODE, may not be passed in registers,
964 but must be passed on the stack. */
965 /* ??? This predicate should be applied strictly after pass-by-reference.
966 Need audit to verify that this is the case. */
967 bool (* must_pass_in_stack) (enum machine_mode mode, const_tree t);
968
969 /* Return true if type TYPE, mode MODE, which is passed by reference,
970 should have the object copy generated by the callee rather than
971 the caller. It is never called for TYPE requiring constructors. */
972 bool (* callee_copies) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
973 const_tree type, bool named);
974
975 /* Return zero for arguments passed entirely on the stack or entirely
976 in registers. If passed in both, return the number of bytes passed
977 in registers; the balance is therefore passed on the stack. */
978 int (* arg_partial_bytes) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
979 tree type, bool named);
980
981 /* Return the diagnostic message string if function without a prototype
982 is not allowed for this 'val' argument; NULL otherwise. */
983 const char *(*invalid_arg_for_unprototyped_fn) (const_tree typelist,
984 const_tree funcdecl,
985 const_tree val);
986
987 /* Return an rtx for the return value location of the function
988 specified by FN_DECL_OR_TYPE with a return type of RET_TYPE. */
989 rtx (*function_value) (const_tree ret_type, const_tree fn_decl_or_type,
990 bool outgoing);
991
992 /* Return the rtx for the result of a libcall of mode MODE,
993 calling the function FN_NAME. */
994 rtx (*libcall_value) (enum machine_mode, const_rtx);
995
996 /* Return true if REGNO is a possible register number for
997 a function value as seen by the caller. */
998 bool (*function_value_regno_p) (const unsigned int);
999
1000 /* Return an rtx for the argument pointer incoming to the
1001 current function. */
1002 rtx (*internal_arg_pointer) (void);
1003
1004 /* Update the current function stack boundary if needed. */
1005 void (*update_stack_boundary) (void);
1006
1007 /* Handle stack alignment and return an rtx for Dynamic Realign
1008 Argument Pointer if necessary. */
1009 rtx (*get_drap_rtx) (void);
1010
1011 /* Return true if all function parameters should be spilled to the
1012 stack. */
1013 bool (*allocate_stack_slots_for_args) (void);
1014
1015 /* Return an rtx for the static chain for FNDECL. If INCOMING_P is true,
1016 then it should be for the callee; otherwise for the caller. */
1017 rtx (*static_chain) (const_tree fndecl, bool incoming_p);
1018
1019 /* Fill in the trampoline at MEM with a call to FNDECL and a
1020 static chain value of CHAIN. */
1021 void (*trampoline_init) (rtx mem, tree fndecl, rtx chain);
1022
1023 /* Adjust the address of the trampoline in a target-specific way. */
1024 rtx (*trampoline_adjust_address) (rtx addr);
1025 } calls;
1026
1027 /* Return the diagnostic message string if conversion from FROMTYPE
1028 to TOTYPE is not allowed, NULL otherwise. */
1029 const char *(*invalid_conversion) (const_tree fromtype, const_tree totype);
1030
1031 /* Return the diagnostic message string if the unary operation OP is
1032 not permitted on TYPE, NULL otherwise. */
1033 const char *(*invalid_unary_op) (int op, const_tree type);
1034
1035 /* Return the diagnostic message string if the binary operation OP
1036 is not permitted on TYPE1 and TYPE2, NULL otherwise. */
1037 const char *(*invalid_binary_op) (int op, const_tree type1, const_tree type2);
1038
1039 /* Return the diagnostic message string if TYPE is not valid as a
1040 function parameter type, NULL otherwise. */
1041 const char *(*invalid_parameter_type) (const_tree type);
1042
1043 /* Return the diagnostic message string if TYPE is not valid as a
1044 function return type, NULL otherwise. */
1045 const char *(*invalid_return_type) (const_tree type);
1046
1047 /* If values of TYPE are promoted to some other type when used in
1048 expressions (analogous to the integer promotions), return that type,
1049 or NULL_TREE otherwise. */
1050 tree (*promoted_type) (const_tree type);
1051
1052 /* Convert EXPR to TYPE, if target-specific types with special conversion
1053 rules are involved. Return the converted expression, or NULL to apply
1054 the standard conversion rules. */
1055 tree (*convert_to_type) (tree type, tree expr);
1056
1057 /* Return the array of IRA cover classes for the current target. */
1058 const enum reg_class *(*ira_cover_classes) (void);
1059
1060 /* Return the class for a secondary reload, and fill in extra information. */
1061 enum reg_class (*secondary_reload) (bool, rtx, enum reg_class,
1062 enum machine_mode,
1063 secondary_reload_info *);
1064
1065 /* This target hook allows the backend to perform additional
1066 processing while initializing for variable expansion. */
1067 void (* expand_to_rtl_hook) (void);
1068
1069 /* This target hook allows the backend to perform additional
1070 instantiations on rtx that are not actually in insns yet,
1071 but will be later. */
1072 void (* instantiate_decls) (void);
1073
1074 /* Return true if is OK to use a hard register REGNO as scratch register
1075 in peephole2. */
1076 bool (* hard_regno_scratch_ok) (unsigned int regno);
1077
1078 /* Return the smallest number of different values for which it is best to
1079 use a jump-table instead of a tree of conditional branches. */
1080 unsigned int (* case_values_threshold) (void);
1081
1082 /* Retutn true if a function must have and use a frame pointer. */
1083 bool (* frame_pointer_required) (void);
1084
1085 /* Returns true if the compiler is allowed to try to replace register number
1086 from-reg with register number to-reg. */
1087 bool (* can_eliminate) (const int, const int);
1088
1089 /* Functions specific to the C family of frontends. */
1090 struct c {
1091 /* Return machine mode for non-standard suffix
1092 or VOIDmode if non-standard suffixes are unsupported. */
1093 enum machine_mode (*mode_for_suffix) (char);
1094 } c;
1095
1096 /* Functions specific to the C++ frontend. */
1097 struct cxx {
1098 /* Return the integer type used for guard variables. */
1099 tree (*guard_type) (void);
1100 /* Return true if only the low bit of the guard should be tested. */
1101 bool (*guard_mask_bit) (void);
1102 /* Returns the size of the array cookie for an array of type. */
1103 tree (*get_cookie_size) (tree);
1104 /* Returns true if the element size should be stored in the
1105 array cookie. */
1106 bool (*cookie_has_size) (void);
1107 /* Allows backends to perform additional processing when
1108 deciding if a class should be exported or imported. */
1109 int (*import_export_class) (tree, int);
1110 /* Returns true if constructors and destructors return "this". */
1111 bool (*cdtor_returns_this) (void);
1112 /* Returns true if the key method for a class can be an inline
1113 function, so long as it is not declared inline in the class
1114 itself. Returning true is the behavior required by the Itanium
1115 C++ ABI. */
1116 bool (*key_method_may_be_inline) (void);
1117 /* DECL is a virtual table, virtual table table, typeinfo object,
1118 or other similar implicit class data object that will be
1119 emitted with external linkage in this translation unit. No ELF
1120 visibility has been explicitly specified. If the target needs
1121 to specify a visibility other than that of the containing class,
1122 use this hook to set DECL_VISIBILITY and
1123 DECL_VISIBILITY_SPECIFIED. */
1124 void (*determine_class_data_visibility) (tree decl);
1125 /* Returns true (the default) if virtual tables and other
1126 similar implicit class data objects are always COMDAT if they
1127 have external linkage. If this hook returns false, then
1128 class data for classes whose virtual table will be emitted in
1129 only one translation unit will not be COMDAT. */
1130 bool (*class_data_always_comdat) (void);
1131 /* Returns true (the default) if the RTTI for the basic types,
1132 which is always defined in the C++ runtime, should be COMDAT;
1133 false if it should not be COMDAT. */
1134 bool (*library_rtti_comdat) (void);
1135 /* Returns true if __aeabi_atexit should be used to register static
1136 destructors. */
1137 bool (*use_aeabi_atexit) (void);
1138 /* Returns true if target may use atexit in the same manner as
1139 __cxa_atexit to register static destructors. */
1140 bool (*use_atexit_for_cxa_atexit) (void);
1141 /* TYPE is a C++ class (i.e., RECORD_TYPE or UNION_TYPE) that
1142 has just been defined. Use this hook to make adjustments to the
1143 class (eg, tweak visibility or perform any other required
1144 target modifications). */
1145 void (*adjust_class_at_definition) (tree type);
1146 } cxx;
1147
1148 /* Functions and data for emulated TLS support. */
1149 struct emutls {
1150 /* Name of the address and common functions. */
1151 const char *get_address;
1152 const char *register_common;
1153
1154 /* Prefixes for proxy variable and template. */
1155 const char *var_section;
1156 const char *tmpl_section;
1157
1158 /* Prefixes for proxy variable and template. */
1159 const char *var_prefix;
1160 const char *tmpl_prefix;
1161
1162 /* Function to generate field definitions of the proxy variable. */
1163 tree (*var_fields) (tree, tree *);
1164
1165 /* Function to initialize a proxy variable. */
1166 tree (*var_init) (tree, tree, tree);
1167
1168 /* Whether we are allowed to alter the usual alignment of the
1169 proxy variable. */
1170 bool var_align_fixed;
1171
1172 /* Whether we can emit debug information for TLS vars. */
1173 bool debug_form_tls_address;
1174 } emutls;
1175
1176 struct target_option_hooks {
1177 /* Function to validate the attribute((option(...))) strings or NULL. If
1178 the option is validated, it is assumed that DECL_FUNCTION_SPECIFIC will
1179 be filled in in the function decl node. */
1180 bool (*valid_attribute_p) (tree, tree, tree, int);
1181
1182 /* Function to save any extra target state in the target options
1183 structure. */
1184 void (*save) (struct cl_target_option *);
1185
1186 /* Function to restore any extra target state from the target options
1187 structure. */
1188 void (*restore) (struct cl_target_option *);
1189
1190 /* Function to print any extra target state from the target options
1191 structure. */
1192 void (*print) (FILE *, int, struct cl_target_option *);
1193
1194 /* Function to parse arguments to be validated for #pragma option, and to
1195 change the state if the options are valid. If the first argument is
1196 NULL, the second argument specifies the default options to use. Return
1197 true if the options are valid, and set the current state. */
1198 bool (*pragma_parse) (tree, tree);
1199
1200 /* Function to determine if one function can inline another function. */
1201 bool (*can_inline_p) (tree, tree);
1202 } target_option;
1203
1204 /* For targets that need to mark extra registers as live on entry to
1205 the function, they should define this target hook and set their
1206 bits in the bitmap passed in. */
1207 void (*live_on_entry) (bitmap);
1208
1209 /* True if unwinding tables should be generated by default. */
1210 bool unwind_tables_default;
1211
1212 /* Leave the boolean fields at the end. */
1213
1214 /* True if arbitrary sections are supported. */
1215 bool have_named_sections;
1216
1217 /* True if we can create zeroed data by switching to a BSS section
1218 and then using ASM_OUTPUT_SKIP to allocate the space. */
1219 bool have_switchable_bss_sections;
1220
1221 /* True if "native" constructors and destructors are supported,
1222 false if we're using collect2 for the job. */
1223 bool have_ctors_dtors;
1224
1225 /* True if thread-local storage is supported. */
1226 bool have_tls;
1227
1228 /* True if a small readonly data section is supported. */
1229 bool have_srodata_section;
1230
1231 /* True if EH frame info sections should be zero-terminated. */
1232 bool terminate_dw2_eh_frame_info;
1233
1234 /* True if #NO_APP should be emitted at the beginning of
1235 assembly output. */
1236 bool file_start_app_off;
1237
1238 /* True if output_file_directive should be called for main_input_filename
1239 at the beginning of assembly output. */
1240 bool file_start_file_directive;
1241
1242 /* True if #pragma extern_prefix is to be supported. */
1243 bool handle_pragma_extern_prefix;
1244
1245 /* True if the target is allowed to reorder memory accesses unless
1246 synchronization is explicitly requested. */
1247 bool relaxed_ordering;
1248
1249 /* Returns true if we should generate exception tables for use with the
1250 ARM EABI. The effects the encoding of function exception specifications.
1251 */
1252 bool arm_eabi_unwinder;
1253
1254 /* Leave the boolean fields at the end. */
1255 };
1256
1257 extern struct gcc_target targetm;
1258
1259 struct gcc_targetcm {
1260 /* Handle target switch CODE (an OPT_* value). ARG is the argument
1261 passed to the switch; it is NULL if no argument was. VALUE is the
1262 value of ARG if CODE specifies a UInteger option, otherwise it is
1263 1 if the positive form of the switch was used and 0 if the negative
1264 form was. Return true if the switch was valid. */
1265 bool (*handle_c_option) (size_t code, const char *arg, int value);
1266 };
1267
1268 /* Each target can provide their own. */
1269 extern struct gcc_targetcm targetcm;
1270
1271 #endif /* GCC_TARGET_H */