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.
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 *);
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);
80 /* The struct used by the secondary_reload target hook. */
81 typedef struct secondary_reload_info
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 . */
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;
94 /* This is defined in sched-int.h . */
97 /* This is defined in ddg.h . */
100 /* This is defined in cfgloop.h . */
103 /* Assembler instructions for creating various kinds of integer object. */
113 /* The target structure. This holds all the backend hooks. */
117 /* Functions that output assembler for the target. */
120 /* Opening and closing parentheses for asm expression grouping. */
121 const char *open_paren, *close_paren;
123 /* Assembler instructions for creating various kinds of integer object. */
125 struct asm_int_op aligned_op, unaligned_op;
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);
134 /* Output code that will globalize a label. */
135 void (* globalize_label) (FILE *, const char *);
137 /* Output code that will globalize a declaration. */
138 void (* globalize_decl_name) (FILE *, tree);
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);
147 /* Output code that will emit a label to divide up the exception
149 void (* except_table_label) (FILE *);
151 /* Emit any directives required to unwind this instruction. */
152 void (* unwind_emit) (FILE *, rtx);
154 /* Output an internal label. */
155 void (* internal_label) (FILE *, const char *, unsigned long);
157 /* Emit a ttype table reference to a typeinfo object. */
158 bool (* ttype) (rtx);
160 /* Emit an assembler directive to set visibility for the symbol
161 associated with the tree decl. */
162 void (* visibility) (tree, int);
164 /* Output the assembler code for entry to a function. */
165 void (* function_prologue) (FILE *, HOST_WIDE_INT);
167 /* Output the assembler code for end of prologue. */
168 void (* function_end_prologue) (FILE *);
170 /* Output the assembler code for start of epilogue. */
171 void (* function_begin_epilogue) (FILE *);
173 /* Output the assembler code for function exit. */
174 void (* function_epilogue) (FILE *, HOST_WIDE_INT);
176 /* Initialize target-specific sections. */
177 void (* init_sections) (void);
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);
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);
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);
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);
201 /* Select a unique section name for DECL. RELOC is the same as
202 for SELECT_SECTION. */
203 void (* unique_section) (tree, int);
205 /* Return the readonly data section associated with function DECL. */
206 section *(* function_rodata_section) (tree);
208 /* Output a constructor for a symbol with a given priority. */
209 void (* constructor) (rtx, int);
211 /* Output a destructor for a symbol with a given priority. */
212 void (* destructor) (rtx, int);
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,
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);
233 /* Output any boilerplate text needed at the beginning of a
235 void (*file_start) (void);
237 /* Output any boilerplate text needed at the end of a
239 void (*file_end) (void);
241 /* Output any boilerplate text needed at the beginning of an
242 LTO output stream. */
243 void (*lto_start) (void);
245 /* Output any boilerplate text needed at the end of an
246 LTO output stream. */
247 void (*lto_end) (void);
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);
253 /* Output an assembler pseudo-op to declare a library function name
255 void (*external_libcall) (rtx);
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 *);
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
267 const char * record_gcc_switches_section;
269 /* Output the definition of a section anchor. */
270 void (*output_anchor) (rtx);
272 /* Output a DTP-relative reference to a TLS symbol. */
273 void (*output_dwarf_dtprel) (FILE *file, int size, rtx x);
275 /* Some target machines need to postscan each insn after it is output. */
276 void (*final_postscan_insn) (FILE *, rtx, rtx *, int);
278 /* Emit the trampoline template. This hook may be NULL. */
279 void (*trampoline_template) (FILE *);
282 /* Functions relating to instruction scheduling. */
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);
290 /* Adjust the priority of an insn as you see fit. Returns the new
292 int (* adjust_priority) (rtx, int);
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);
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);
303 /* Initialize machine-dependent scheduling code. */
304 void (* md_init) (FILE *, int, int);
306 /* Finalize machine-dependent scheduling code. */
307 void (* md_finish) (FILE *, int);
309 /* Initialize machine-dependent function wide scheduling code. */
310 void (* md_init_global) (FILE *, int, int);
312 /* Finalize machine-dependent function wide scheduling code. */
313 void (* md_finish_global) (FILE *, int);
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);
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);
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
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);
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);
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);
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
362 int (* first_cycle_multipass_dfa_lookahead_guard) (rtx);
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
376 int (* dfa_new_cycle) (FILE *, int, rtx, int, int, int *);
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);
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);
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);
399 /* Next 5 functions are for multi-point scheduling. */
401 /* Allocate memory for scheduler context. */
402 void *(* alloc_sched_context) (void);
404 /* Fills the context from the local machine scheduler context. */
405 void (* init_sched_context) (void *, bool);
407 /* Sets local machine scheduler context to a saved value. */
408 void (* set_sched_context) (void *);
410 /* Clears a scheduler context so it becomes like after init. */
411 void (* clear_sched_context) (void *);
413 /* Frees the scheduler context. */
414 void (* free_sched_context) (void *);
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).
422 -1, if there is no pattern, that will satisfy the requested speculation
424 0, if current pattern satisfies the requested speculation type,
425 1, if pattern of the instruction should be changed to the newly
427 int (* speculate_insn) (rtx, int, rtx *);
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);
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
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);
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);
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 *);
457 /* Return speculation types of the instruction passed as the parameter. */
458 int (* get_insn_spec_ds) (rtx);
460 /* Return speculation types that are checked for the instruction passed as
462 int (* get_insn_checked_ds) (rtx);
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);
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
472 int (* sms_res_mii) (struct ddg *);
475 /* Functions relating to vectorization. */
478 /* The following member value is a pointer to a function called
479 by the vectorizer, and return the decl of the target builtin
481 tree (* builtin_mask_for_load) (void);
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);
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);
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);
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);
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);
506 /* Target builtin that implements vector permute. */
507 tree (* builtin_vec_perm) (tree, tree*);
509 /* Return true if a vector created for builtin_vec_perm is valid. */
510 bool (* builtin_vec_perm_ok) (tree, tree);
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);
519 /* The initial value of target_flags. */
520 int default_target_flags;
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);
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);
534 /* Display extra, target specific information in response to a
535 --target-help switch. */
536 void (* target_help) (void);
538 /* Return machine mode for filter value. */
539 enum machine_mode (* eh_return_filter_mode) (void);
541 /* Return machine mode for libgcc expanded cmp instructions. */
542 enum machine_mode (* libgcc_cmp_return_mode) (void);
544 /* Return machine mode for libgcc expanded shift instructions. */
545 enum machine_mode (* libgcc_shift_count_mode) (void);
547 /* Return machine mode to be used for _Unwind_Word type. */
548 enum machine_mode (* unwind_word_mode) (void);
550 /* Given two decls, merge their attributes and return the result. */
551 tree (* merge_decl_attributes) (tree, tree);
553 /* Given two types, merge their attributes and return the result. */
554 tree (* merge_type_attributes) (tree, tree);
556 /* Table of machine attributes and functions to handle them.
558 const struct attribute_spec *attribute_table;
560 /* Return true iff attribute NAME expects a plain identifier as its first
562 bool (*attribute_takes_identifier_p) (const_tree name);
564 /* Return zero if the attributes on TYPE1 and TYPE2 are incompatible,
565 one if they are compatible and two if they are nearly compatible
566 (which causes a warning to be generated). */
567 int (* comp_type_attributes) (const_tree type1, const_tree type2);
569 /* Assign default attributes to the newly defined TYPE. */
570 void (* set_default_type_attributes) (tree type);
572 /* Insert attributes on the newly created DECL. */
573 void (* insert_attributes) (tree decl, tree *attributes);
575 /* Return true if FNDECL (which has at least one machine attribute)
576 can be inlined despite its machine attributes, false otherwise. */
577 bool (* function_attribute_inlinable_p) (const_tree fndecl);
579 /* Return true if bitfields in RECORD_TYPE should follow the
580 Microsoft Visual C++ bitfield layout rules. */
581 bool (* ms_bitfield_layout_p) (const_tree record_type);
583 /* True if the target supports decimal floating point. */
584 bool (* decimal_float_supported_p) (void);
586 /* True if the target supports fixed-point. */
587 bool (* fixed_point_supported_p) (void);
589 /* Return true if anonymous bitfields affect structure alignment. */
590 bool (* align_anon_bitfield) (void);
592 /* Return true if volatile bitfields should use the narrowest type possible.
593 Return false if they should use the container type. */
594 bool (* narrow_volatile_bitfield) (void);
596 /* Set up target-specific built-in functions. */
597 void (* init_builtins) (void);
599 /* Initialize (if INITIALIZE_P is true) and return the target-specific
600 built-in function decl for CODE.
601 Return NULL if that is not possible. Return error_mark_node if CODE
602 is outside of the range of valid target builtin function codes. */
603 tree (* builtin_decl) (unsigned code, bool initialize_p);
605 /* Expand a target-specific builtin. */
606 rtx (* expand_builtin) (tree exp, rtx target, rtx subtarget,
607 enum machine_mode mode, int ignore);
609 /* Select a replacement for a target-specific builtin. This is done
610 *before* regular type checking, and so allows the target to
611 implement a crude form of function overloading. The result is a
612 complete expression that implements the operation. PARAMS really
613 has type VEC(tree,gc)*, but we don't want to include tree.h
615 tree (*resolve_overloaded_builtin) (unsigned int /*location_t*/,
616 tree decl, void *params);
618 /* Fold a target-specific builtin. */
619 tree (* fold_builtin) (tree fndecl, tree arglist, bool ignore);
621 /* Returns a code for a target-specific builtin that implements
622 reciprocal of the function, or NULL_TREE if not available. */
623 tree (* builtin_reciprocal) (unsigned, bool, bool);
625 /* For a vendor-specific TYPE, return a pointer to a statically-allocated
626 string containing the C++ mangling for TYPE. In all other cases, return
628 const char * (* mangle_type) (const_tree type);
630 /* Make any adjustments to libfunc names needed for this target. */
631 void (* init_libfuncs) (void);
633 /* Given a decl, a section name, and whether the decl initializer
634 has relocs, choose attributes for the section. */
635 /* ??? Should be merged with SELECT_SECTION and UNIQUE_SECTION. */
636 unsigned int (* section_type_flags) (tree, const char *, int);
638 /* True if new jumps cannot be created, to replace existing ones or
639 not, at the current point in the compilation. */
640 bool (* cannot_modify_jumps_p) (void);
642 /* Return a register class for which branch target register
643 optimizations should be applied. */
644 enum reg_class (* branch_target_register_class) (void);
646 /* Return true if branch target register optimizations should include
647 callee-saved registers that are not already live during the current
648 function. AFTER_PE_GEN is true if prologues and epilogues have
649 already been generated. */
650 bool (* branch_target_register_callee_saved) (bool after_pe_gen);
652 /* Return true if the target supports conditional execution. */
653 bool (* have_conditional_execution) (void);
655 /* Return a new value for loop unroll size. */
656 unsigned (* loop_unroll_adjust) (unsigned nunroll, struct loop *loop);
658 /* True if the constant X cannot be placed in the constant pool. */
659 bool (* cannot_force_const_mem) (rtx);
661 /* True if the insn X cannot be duplicated. */
662 bool (* cannot_copy_insn_p) (rtx);
664 /* True if X is considered to be commutative. */
665 bool (* commutative_p) (const_rtx, int);
667 /* Given an invalid address X for a given machine mode, try machine-specific
668 ways to make it legitimate. Return X or an invalid address on failure. */
669 rtx (* legitimize_address) (rtx, rtx, enum machine_mode);
671 /* Given an address RTX, undo the effects of LEGITIMIZE_ADDRESS. */
672 rtx (* delegitimize_address) (rtx);
674 /* Given an address RTX, say whether it is valid. */
675 bool (* legitimate_address_p) (enum machine_mode, rtx, bool);
677 /* True if the given constant can be put into an object_block. */
678 bool (* use_blocks_for_constant_p) (enum machine_mode, const_rtx);
680 /* The minimum and maximum byte offsets for anchored addresses. */
681 HOST_WIDE_INT min_anchor_offset;
682 HOST_WIDE_INT max_anchor_offset;
684 /* True if section anchors can be used to access the given symbol. */
685 bool (* use_anchors_for_symbol_p) (const_rtx);
687 /* True if it is OK to do sibling call optimization for the specified
688 call expression EXP. DECL will be the called function, or NULL if
689 this is an indirect call. */
690 bool (*function_ok_for_sibcall) (tree decl, tree exp);
692 /* Establish appropriate back-end context for processing the function
693 FNDECL. The argument might be NULL to indicate processing at top
694 level, outside of any function scope. */
695 void (*set_current_function) (tree fndecl);
697 /* True if EXP should be placed in a "small data" section. */
698 bool (* in_small_data_p) (const_tree);
700 /* True if EXP names an object for which name resolution must resolve
701 to the current executable or shared library. */
702 bool (* binds_local_p) (const_tree);
704 /* Modify and return the identifier of a DECL's external name,
705 originally identified by ID, as required by the target,
706 (eg, append @nn to windows32 stdcall function names).
707 The default is to return ID without modification. */
708 tree (* mangle_decl_assembler_name) (tree decl, tree id);
710 /* Do something target-specific to record properties of the DECL into
711 the associated SYMBOL_REF. */
712 void (* encode_section_info) (tree, rtx, int);
714 /* Undo the effects of encode_section_info on the symbol string. */
715 const char * (* strip_name_encoding) (const char *);
717 /* If shift optabs for MODE are known to always truncate the shift count,
718 return the mask that they apply. Return 0 otherwise. */
719 unsigned HOST_WIDE_INT (* shift_truncation_mask) (enum machine_mode mode);
721 /* Return the number of divisions in the given MODE that should be present,
722 so that it is profitable to turn the division into a multiplication by
724 unsigned int (* min_divisions_for_recip_mul) (enum machine_mode mode);
726 /* If the representation of integral MODE is such that values are
727 always sign-extended to a wider mode MODE_REP then return
728 SIGN_EXTEND. Return UNKNOWN otherwise. */
729 /* Note that the return type ought to be RTX_CODE, but that's not
730 necessarily defined at this point. */
731 int (* mode_rep_extended) (enum machine_mode mode,
732 enum machine_mode mode_rep);
734 /* True if MODE is valid for a pointer in __attribute__((mode("MODE"))). */
735 bool (* valid_pointer_mode) (enum machine_mode mode);
737 /* Support for named address spaces. */
739 /* MODE to use for a pointer into another address space. */
740 enum machine_mode (* pointer_mode) (addr_space_t);
742 /* MODE to use for an address in another address space. */
743 enum machine_mode (* address_mode) (addr_space_t);
745 /* True if MODE is valid for a pointer in __attribute__((mode("MODE")))
746 in another address space. */
747 bool (* valid_pointer_mode) (enum machine_mode, addr_space_t);
749 /* True if an address is a valid memory address to a given named address
750 space for a given mode. */
751 bool (* legitimate_address_p) (enum machine_mode, rtx, bool, addr_space_t);
753 /* Return an updated address to convert an invalid pointer to a named
754 address space to a valid one. If NULL_RTX is returned use machine
755 independent methods to make the address valid. */
756 rtx (* legitimize_address) (rtx, rtx, enum machine_mode, addr_space_t);
758 /* True if one named address space is a subset of another named address. */
759 bool (* subset_p) (addr_space_t, addr_space_t);
761 /* Function to convert an rtl expression from one address space to
763 rtx (* convert) (rtx, tree, tree);
767 /* True if MODE is valid for the target. By "valid", we mean able to
768 be manipulated in non-trivial ways. In particular, this means all
769 the arithmetic is supported. */
770 bool (* scalar_mode_supported_p) (enum machine_mode mode);
772 /* Similarly for vector modes. "Supported" here is less strict. At
773 least some operations are supported; need to check optabs or builtins
774 for further details. */
775 bool (* vector_mode_supported_p) (enum machine_mode mode);
777 /* True for MODE if the target expects that registers in this mode will
778 be allocated to registers in a small register class. The compiler is
779 allowed to use registers explicitly used in the rtl as spill registers
780 but it should prevent extending the lifetime of these registers. */
781 bool (* small_register_classes_for_mode_p) (enum machine_mode mode);
783 /* Compute a (partial) cost for rtx X. Return true if the complete
784 cost has been computed, and false if subexpressions should be
785 scanned. In either case, *TOTAL contains the cost result. */
786 /* Note that CODE and OUTER_CODE ought to be RTX_CODE, but that's
787 not necessarily defined at this point. */
788 bool (* rtx_costs) (rtx x, int code, int outer_code, int *total, bool speed);
790 /* Compute the cost of X, used as an address. Never called with
791 invalid addresses. */
792 int (* address_cost) (rtx x, bool speed);
794 /* Return where to allocate pseudo for a given hard register initial
796 rtx (* allocate_initial_value) (rtx x);
798 /* Return nonzero if evaluating UNSPEC[_VOLATILE] X might cause a trap.
799 FLAGS has the same meaning as in rtlanal.c: may_trap_p_1. */
800 int (* unspec_may_trap_p) (const_rtx x, unsigned flags);
802 /* Given a register, this hook should return a parallel of registers
803 to represent where to find the register pieces. Define this hook
804 if the register and its mode are represented in Dwarf in
805 non-contiguous locations, or if the register should be
806 represented in more than one register in Dwarf. Otherwise, this
807 hook should return NULL_RTX. */
808 rtx (* dwarf_register_span) (rtx);
810 /* If expand_builtin_init_dwarf_reg_sizes needs to fill in table
811 entries not corresponding directly to registers below
812 FIRST_PSEUDO_REGISTER, this hook should generate the necessary
813 code, given the address of the table. */
814 void (* init_dwarf_reg_sizes_extra) (tree);
816 /* Fetch the fixed register(s) which hold condition codes, for
817 targets where it makes sense to look for duplicate assignments to
818 the condition codes. This should return true if there is such a
819 register, false otherwise. The arguments should be set to the
820 fixed register numbers. Up to two condition code registers are
821 supported. If there is only one for this target, the int pointed
822 at by the second argument should be set to -1. */
823 bool (* fixed_condition_code_regs) (unsigned int *, unsigned int *);
825 /* If two condition code modes are compatible, return a condition
826 code mode which is compatible with both, such that a comparison
827 done in the returned mode will work for both of the original
828 modes. If the condition code modes are not compatible, return
830 enum machine_mode (* cc_modes_compatible) (enum machine_mode,
833 /* Do machine-dependent code transformations. Called just before
834 delayed-branch scheduling. */
835 void (* machine_dependent_reorg) (void);
837 /* Create the __builtin_va_list type. */
838 tree (* build_builtin_va_list) (void);
840 /* Get the cfun/fndecl calling abi __builtin_va_list type. */
841 tree (* fn_abi_va_list) (tree);
843 /* Get the __builtin_va_list type dependent on input type. */
844 tree (* canonical_va_list_type) (tree);
846 /* Expand the __builtin_va_start builtin. */
847 void (* expand_builtin_va_start) (tree valist, rtx nextarg);
849 /* Gimplifies a VA_ARG_EXPR. */
850 tree (* gimplify_va_arg_expr) (tree valist, tree type, gimple_seq *pre_p,
853 /* Validity-checking routines for PCH files, target-specific.
854 get_pch_validity returns a pointer to the data to be stored,
855 and stores the size in its argument. pch_valid_p gets the same
856 information back and returns NULL if the PCH is valid,
857 or an error message if not.
859 void * (* get_pch_validity) (size_t *);
860 const char * (* pch_valid_p) (const void *, size_t);
862 /* If nonnull, this function checks whether a PCH file with the
863 given set of target flags can be used. It returns NULL if so,
864 otherwise it returns an error message. */
865 const char *(*check_pch_target_flags) (int);
867 /* True if the compiler should give an enum type only as many
868 bytes as it takes to represent the range of possible values of
870 bool (* default_short_enums) (void);
872 /* This target hook returns an rtx that is used to store the address
873 of the current frame into the built-in setjmp buffer. */
874 rtx (* builtin_setjmp_frame_value) (void);
876 /* This target hook should add STRING_CST trees for any hard regs
877 the port wishes to automatically clobber for an asm. */
878 tree (* md_asm_clobbers) (tree, tree, tree);
880 /* This target hook allows the backend to specify a calling convention
881 in the debug information. This function actually returns an
882 enum dwarf_calling_convention, but because of forward declarations
883 and not wanting to include dwarf2.h everywhere target.h is included
884 the function is being declared as an int. */
885 int (* dwarf_calling_convention) (const_tree);
887 /* This target hook allows the backend to emit frame-related insns that
888 contain UNSPECs or UNSPEC_VOLATILEs. The call frame debugging info
889 engine will invoke it on insns of the form
890 (set (reg) (unspec [...] UNSPEC_INDEX))
892 (set (reg) (unspec_volatile [...] UNSPECV_INDEX))
893 to let the backend emit the call frame instructions. */
894 void (* dwarf_handle_frame_unspec) (const char *, rtx, int);
896 /* Perform architecture specific checking of statements gimplified
897 from VA_ARG_EXPR. STMT is the statement. Returns true if the statement
898 doesn't need to be checked for va_list references. */
899 bool (* stdarg_optimize_hook) (struct stdarg_info *ai, const_gimple stmt);
901 /* This target hook allows the operating system to override the DECL
902 that represents the external variable that contains the stack
903 protection guard variable. The type of this DECL is ptr_type_node. */
904 tree (* stack_protect_guard) (void);
906 /* This target hook allows the operating system to override the CALL_EXPR
907 that is invoked when a check vs the guard variable fails. */
908 tree (* stack_protect_fail) (void);
910 /* Returns NULL if target supports the insn within a doloop block,
911 otherwise it returns an error message. */
912 const char * (*invalid_within_doloop) (const_rtx);
914 /* DECL is a variable or function with __attribute__((dllimport))
915 specified. Use this hook if the target needs to add extra validation
916 checks to handle_dll_attribute (). */
917 bool (* valid_dllimport_attribute_p) (const_tree decl);
919 /* If non-zero, align constant anchors in CSE to a multiple of this
921 unsigned HOST_WIDE_INT const_anchor;
923 /* Functions relating to calls - argument passing, returns, etc. */
925 enum machine_mode (*promote_function_mode) (const_tree type,
926 enum machine_mode mode,
930 bool (*promote_prototypes) (const_tree fntype);
931 rtx (*struct_value_rtx) (tree fndecl, int incoming);
932 bool (*return_in_memory) (const_tree type, const_tree fndecl);
933 bool (*return_in_msb) (const_tree type);
935 /* Return true if a parameter must be passed by reference. TYPE may
936 be null if this is a libcall. CA may be null if this query is
937 from __builtin_va_arg. */
938 bool (*pass_by_reference) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
939 const_tree type, bool named_arg);
941 rtx (*expand_builtin_saveregs) (void);
942 /* Returns pretend_argument_size. */
943 void (*setup_incoming_varargs) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
944 tree type, int *pretend_arg_size,
946 bool (*strict_argument_naming) (CUMULATIVE_ARGS *ca);
947 /* Returns true if we should use
948 targetm.calls.setup_incoming_varargs() and/or
949 targetm.calls.strict_argument_naming(). */
950 bool (*pretend_outgoing_varargs_named) (CUMULATIVE_ARGS *ca);
952 /* Given a complex type T, return true if a parameter of type T
953 should be passed as two scalars. */
954 bool (* split_complex_arg) (const_tree type);
956 /* Return true if type T, mode MODE, may not be passed in registers,
957 but must be passed on the stack. */
958 /* ??? This predicate should be applied strictly after pass-by-reference.
959 Need audit to verify that this is the case. */
960 bool (* must_pass_in_stack) (enum machine_mode mode, const_tree t);
962 /* Return true if type TYPE, mode MODE, which is passed by reference,
963 should have the object copy generated by the callee rather than
964 the caller. It is never called for TYPE requiring constructors. */
965 bool (* callee_copies) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
966 const_tree type, bool named);
968 /* Return zero for arguments passed entirely on the stack or entirely
969 in registers. If passed in both, return the number of bytes passed
970 in registers; the balance is therefore passed on the stack. */
971 int (* arg_partial_bytes) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
972 tree type, bool named);
974 /* Return the diagnostic message string if function without a prototype
975 is not allowed for this 'val' argument; NULL otherwise. */
976 const char *(*invalid_arg_for_unprototyped_fn) (const_tree typelist,
980 /* Return an rtx for the return value location of the function
981 specified by FN_DECL_OR_TYPE with a return type of RET_TYPE. */
982 rtx (*function_value) (const_tree ret_type, const_tree fn_decl_or_type,
985 /* Return the rtx for the result of a libcall of mode MODE,
986 calling the function FN_NAME. */
987 rtx (*libcall_value) (enum machine_mode, const_rtx);
989 /* Return true if REGNO is a possible register number for
990 a function value as seen by the caller. */
991 bool (*function_value_regno_p) (const unsigned int);
993 /* Return an rtx for the argument pointer incoming to the
995 rtx (*internal_arg_pointer) (void);
997 /* Update the current function stack boundary if needed. */
998 void (*update_stack_boundary) (void);
1000 /* Handle stack alignment and return an rtx for Dynamic Realign
1001 Argument Pointer if necessary. */
1002 rtx (*get_drap_rtx) (void);
1004 /* Return true if all function parameters should be spilled to the
1006 bool (*allocate_stack_slots_for_args) (void);
1008 /* Return an rtx for the static chain for FNDECL. If INCOMING_P is true,
1009 then it should be for the callee; otherwise for the caller. */
1010 rtx (*static_chain) (const_tree fndecl, bool incoming_p);
1012 /* Fill in the trampoline at MEM with a call to FNDECL and a
1013 static chain value of CHAIN. */
1014 void (*trampoline_init) (rtx mem, tree fndecl, rtx chain);
1016 /* Adjust the address of the trampoline in a target-specific way. */
1017 rtx (*trampoline_adjust_address) (rtx addr);
1020 /* Return the diagnostic message string if conversion from FROMTYPE
1021 to TOTYPE is not allowed, NULL otherwise. */
1022 const char *(*invalid_conversion) (const_tree fromtype, const_tree totype);
1024 /* Return the diagnostic message string if the unary operation OP is
1025 not permitted on TYPE, NULL otherwise. */
1026 const char *(*invalid_unary_op) (int op, const_tree type);
1028 /* Return the diagnostic message string if the binary operation OP
1029 is not permitted on TYPE1 and TYPE2, NULL otherwise. */
1030 const char *(*invalid_binary_op) (int op, const_tree type1, const_tree type2);
1032 /* Return the diagnostic message string if TYPE is not valid as a
1033 function parameter type, NULL otherwise. */
1034 const char *(*invalid_parameter_type) (const_tree type);
1036 /* Return the diagnostic message string if TYPE is not valid as a
1037 function return type, NULL otherwise. */
1038 const char *(*invalid_return_type) (const_tree type);
1040 /* If values of TYPE are promoted to some other type when used in
1041 expressions (analogous to the integer promotions), return that type,
1042 or NULL_TREE otherwise. */
1043 tree (*promoted_type) (const_tree type);
1045 /* Convert EXPR to TYPE, if target-specific types with special conversion
1046 rules are involved. Return the converted expression, or NULL to apply
1047 the standard conversion rules. */
1048 tree (*convert_to_type) (tree type, tree expr);
1050 /* Return the array of IRA cover classes for the current target. */
1051 const enum reg_class *(*ira_cover_classes) (void);
1053 /* Return the class for a secondary reload, and fill in extra information. */
1054 enum reg_class (*secondary_reload) (bool, rtx, enum reg_class,
1056 secondary_reload_info *);
1058 /* This target hook allows the backend to perform additional
1059 processing while initializing for variable expansion. */
1060 void (* expand_to_rtl_hook) (void);
1062 /* This target hook allows the backend to perform additional
1063 instantiations on rtx that are not actually in insns yet,
1064 but will be later. */
1065 void (* instantiate_decls) (void);
1067 /* Return true if is OK to use a hard register REGNO as scratch register
1069 bool (* hard_regno_scratch_ok) (unsigned int regno);
1071 /* Return the smallest number of different values for which it is best to
1072 use a jump-table instead of a tree of conditional branches. */
1073 unsigned int (* case_values_threshold) (void);
1075 /* Retutn true if a function must have and use a frame pointer. */
1076 bool (* frame_pointer_required) (void);
1078 /* Returns true if the compiler is allowed to try to replace register number
1079 from-reg with register number to-reg. */
1080 bool (* can_eliminate) (const int, const int);
1082 /* Functions specific to the C family of frontends. */
1084 /* Return machine mode for non-standard suffix
1085 or VOIDmode if non-standard suffixes are unsupported. */
1086 enum machine_mode (*mode_for_suffix) (char);
1089 /* Functions specific to the C++ frontend. */
1091 /* Return the integer type used for guard variables. */
1092 tree (*guard_type) (void);
1093 /* Return true if only the low bit of the guard should be tested. */
1094 bool (*guard_mask_bit) (void);
1095 /* Returns the size of the array cookie for an array of type. */
1096 tree (*get_cookie_size) (tree);
1097 /* Returns true if the element size should be stored in the
1099 bool (*cookie_has_size) (void);
1100 /* Allows backends to perform additional processing when
1101 deciding if a class should be exported or imported. */
1102 int (*import_export_class) (tree, int);
1103 /* Returns true if constructors and destructors return "this". */
1104 bool (*cdtor_returns_this) (void);
1105 /* Returns true if the key method for a class can be an inline
1106 function, so long as it is not declared inline in the class
1107 itself. Returning true is the behavior required by the Itanium
1109 bool (*key_method_may_be_inline) (void);
1110 /* DECL is a virtual table, virtual table table, typeinfo object,
1111 or other similar implicit class data object that will be
1112 emitted with external linkage in this translation unit. No ELF
1113 visibility has been explicitly specified. If the target needs
1114 to specify a visibility other than that of the containing class,
1115 use this hook to set DECL_VISIBILITY and
1116 DECL_VISIBILITY_SPECIFIED. */
1117 void (*determine_class_data_visibility) (tree decl);
1118 /* Returns true (the default) if virtual tables and other
1119 similar implicit class data objects are always COMDAT if they
1120 have external linkage. If this hook returns false, then
1121 class data for classes whose virtual table will be emitted in
1122 only one translation unit will not be COMDAT. */
1123 bool (*class_data_always_comdat) (void);
1124 /* Returns true (the default) if the RTTI for the basic types,
1125 which is always defined in the C++ runtime, should be COMDAT;
1126 false if it should not be COMDAT. */
1127 bool (*library_rtti_comdat) (void);
1128 /* Returns true if __aeabi_atexit should be used to register static
1130 bool (*use_aeabi_atexit) (void);
1131 /* Returns true if target may use atexit in the same manner as
1132 __cxa_atexit to register static destructors. */
1133 bool (*use_atexit_for_cxa_atexit) (void);
1134 /* TYPE is a C++ class (i.e., RECORD_TYPE or UNION_TYPE) that
1135 has just been defined. Use this hook to make adjustments to the
1136 class (eg, tweak visibility or perform any other required
1137 target modifications). */
1138 void (*adjust_class_at_definition) (tree type);
1141 /* Functions and data for emulated TLS support. */
1143 /* Name of the address and common functions. */
1144 const char *get_address;
1145 const char *register_common;
1147 /* Prefixes for proxy variable and template. */
1148 const char *var_section;
1149 const char *tmpl_section;
1151 /* Prefixes for proxy variable and template. */
1152 const char *var_prefix;
1153 const char *tmpl_prefix;
1155 /* Function to generate field definitions of the proxy variable. */
1156 tree (*var_fields) (tree, tree *);
1158 /* Function to initialize a proxy variable. */
1159 tree (*var_init) (tree, tree, tree);
1161 /* Whether we are allowed to alter the usual alignment of the
1163 bool var_align_fixed;
1165 /* Whether we can emit debug information for TLS vars. */
1166 bool debug_form_tls_address;
1169 struct target_option_hooks {
1170 /* Function to validate the attribute((option(...))) strings or NULL. If
1171 the option is validated, it is assumed that DECL_FUNCTION_SPECIFIC will
1172 be filled in in the function decl node. */
1173 bool (*valid_attribute_p) (tree, tree, tree, int);
1175 /* Function to save any extra target state in the target options
1177 void (*save) (struct cl_target_option *);
1179 /* Function to restore any extra target state from the target options
1181 void (*restore) (struct cl_target_option *);
1183 /* Function to print any extra target state from the target options
1185 void (*print) (FILE *, int, struct cl_target_option *);
1187 /* Function to parse arguments to be validated for #pragma option, and to
1188 change the state if the options are valid. If the first argument is
1189 NULL, the second argument specifies the default options to use. Return
1190 true if the options are valid, and set the current state. */
1191 bool (*pragma_parse) (tree, tree);
1193 /* Function to determine if one function can inline another function. */
1194 bool (*can_inline_p) (tree, tree);
1197 /* For targets that need to mark extra registers as live on entry to
1198 the function, they should define this target hook and set their
1199 bits in the bitmap passed in. */
1200 void (*live_on_entry) (bitmap);
1202 /* True if unwinding tables should be generated by default. */
1203 bool unwind_tables_default;
1205 /* Leave the boolean fields at the end. */
1207 /* True if arbitrary sections are supported. */
1208 bool have_named_sections;
1210 /* True if we can create zeroed data by switching to a BSS section
1211 and then using ASM_OUTPUT_SKIP to allocate the space. */
1212 bool have_switchable_bss_sections;
1214 /* True if "native" constructors and destructors are supported,
1215 false if we're using collect2 for the job. */
1216 bool have_ctors_dtors;
1218 /* True if thread-local storage is supported. */
1221 /* True if a small readonly data section is supported. */
1222 bool have_srodata_section;
1224 /* True if EH frame info sections should be zero-terminated. */
1225 bool terminate_dw2_eh_frame_info;
1227 /* True if #NO_APP should be emitted at the beginning of
1229 bool file_start_app_off;
1231 /* True if output_file_directive should be called for main_input_filename
1232 at the beginning of assembly output. */
1233 bool file_start_file_directive;
1235 /* True if #pragma extern_prefix is to be supported. */
1236 bool handle_pragma_extern_prefix;
1238 /* True if the target is allowed to reorder memory accesses unless
1239 synchronization is explicitly requested. */
1240 bool relaxed_ordering;
1242 /* Returns true if we should generate exception tables for use with the
1243 ARM EABI. The effects the encoding of function exception specifications.
1245 bool arm_eabi_unwinder;
1247 /* Leave the boolean fields at the end. */
1250 extern struct gcc_target targetm;
1252 struct gcc_targetcm {
1253 /* Handle target switch CODE (an OPT_* value). ARG is the argument
1254 passed to the switch; it is NULL if no argument was. VALUE is the
1255 value of ARG if CODE specifies a UInteger option, otherwise it is
1256 1 if the positive form of the switch was used and 0 if the negative
1257 form was. Return true if the switch was valid. */
1258 bool (*handle_c_option) (size_t code, const char *arg, int value);
1261 /* Each target can provide their own. */
1262 extern struct gcc_targetcm targetcm;
1264 #endif /* GCC_TARGET_H */
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