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 boilerplace text needed at the end of a
242 translation unit before debug and unwind info is emitted. */
243 void (*code_end) (void);
245 /* Output an assembler pseudo-op to declare a library function name
247 void (*external_libcall) (rtx);
249 /* Output an assembler directive to mark decl live. This instructs
250 linker to not dead code strip this symbol. */
251 void (*mark_decl_preserved) (const char *);
253 /* Output a record of the command line switches that have been passed. */
254 print_switch_fn_type record_gcc_switches;
255 /* The name of the section that the example ELF implementation of
256 record_gcc_switches will use to store the information. Target
257 specific versions of record_gcc_switches may or may not use
259 const char * record_gcc_switches_section;
261 /* Output the definition of a section anchor. */
262 void (*output_anchor) (rtx);
264 /* Output a DTP-relative reference to a TLS symbol. */
265 void (*output_dwarf_dtprel) (FILE *file, int size, rtx x);
267 /* Some target machines need to postscan each insn after it is output. */
268 void (*final_postscan_insn) (FILE *, rtx, rtx *, int);
270 /* Emit the trampoline template. This hook may be NULL. */
271 void (*trampoline_template) (FILE *);
274 /* Functions relating to instruction scheduling. */
277 /* Given the current cost, COST, of an insn, INSN, calculate and
278 return a new cost based on its relationship to DEP_INSN through
279 the dependence LINK. The default is to make no adjustment. */
280 int (* adjust_cost) (rtx insn, rtx link, rtx dep_insn, int cost);
282 /* Adjust the priority of an insn as you see fit. Returns the new
284 int (* adjust_priority) (rtx, int);
286 /* Function which returns the maximum number of insns that can be
287 scheduled in the same machine cycle. This must be constant
288 over an entire compilation. The default is 1. */
289 int (* issue_rate) (void);
291 /* Calculate how much this insn affects how many more insns we
292 can emit this cycle. Default is they all cost the same. */
293 int (* variable_issue) (FILE *, int, rtx, int);
295 /* Initialize machine-dependent scheduling code. */
296 void (* md_init) (FILE *, int, int);
298 /* Finalize machine-dependent scheduling code. */
299 void (* md_finish) (FILE *, int);
301 /* Initialize machine-dependent function wide scheduling code. */
302 void (* md_init_global) (FILE *, int, int);
304 /* Finalize machine-dependent function wide scheduling code. */
305 void (* md_finish_global) (FILE *, int);
307 /* Reorder insns in a machine-dependent fashion, in two different
308 places. Default does nothing. */
309 int (* reorder) (FILE *, int, rtx *, int *, int);
310 int (* reorder2) (FILE *, int, rtx *, int *, int);
312 /* The following member value is a pointer to a function called
313 after evaluation forward dependencies of insns in chain given
314 by two parameter values (head and tail correspondingly). */
315 void (* dependencies_evaluation_hook) (rtx, rtx);
317 /* The values of the following four members are pointers to
318 functions used to simplify the automaton descriptions.
319 dfa_pre_cycle_insn and dfa_post_cycle_insn give functions
320 returning insns which are used to change the pipeline hazard
321 recognizer state when the new simulated processor cycle
322 correspondingly starts and finishes. The function defined by
323 init_dfa_pre_cycle_insn and init_dfa_post_cycle_insn are used
324 to initialize the corresponding insns. The default values of
325 the members result in not changing the automaton state when
326 the new simulated processor cycle correspondingly starts and
328 void (* init_dfa_pre_cycle_insn) (void);
329 rtx (* dfa_pre_cycle_insn) (void);
330 void (* init_dfa_post_cycle_insn) (void);
331 rtx (* dfa_post_cycle_insn) (void);
333 /* The values of the following two members are pointers to
334 functions used to simplify the automaton descriptions.
335 dfa_pre_advance_cycle and dfa_post_advance_cycle are getting called
336 immediately before and after cycle is advanced. */
337 void (* dfa_pre_advance_cycle) (void);
338 void (* dfa_post_advance_cycle) (void);
340 /* The following member value is a pointer to a function returning value
341 which defines how many insns in queue `ready' will we try for
342 multi-pass scheduling. If the member value is nonzero and the
343 function returns positive value, the DFA based scheduler will make
344 multi-pass scheduling for the first cycle. In other words, we will
345 try to choose ready insn which permits to start maximum number of
346 insns on the same cycle. */
347 int (* first_cycle_multipass_dfa_lookahead) (void);
349 /* The following member value is pointer to a function controlling
350 what insns from the ready insn queue will be considered for the
351 multipass insn scheduling. If the hook returns zero for insn
352 passed as the parameter, the insn will be not chosen to be
354 int (* first_cycle_multipass_dfa_lookahead_guard) (rtx);
356 /* The following member value is pointer to a function called by
357 the insn scheduler before issuing insn passed as the third
358 parameter on given cycle. If the hook returns nonzero, the
359 insn is not issued on given processors cycle. Instead of that,
360 the processor cycle is advanced. If the value passed through
361 the last parameter is zero, the insn ready queue is not sorted
362 on the new cycle start as usually. The first parameter passes
363 file for debugging output. The second one passes the scheduler
364 verbose level of the debugging output. The forth and the fifth
365 parameter values are correspondingly processor cycle on which
366 the previous insn has been issued and the current processor
368 int (* dfa_new_cycle) (FILE *, int, rtx, int, int, int *);
370 /* The following member value is a pointer to a function called by the
371 insn scheduler. It should return true if there exists a dependence
372 which is considered costly by the target, between the insn
373 DEP_PRO (&_DEP), and the insn DEP_CON (&_DEP). The first parameter is
374 the dep that represents the dependence between the two insns. The
375 second argument is the cost of the dependence as estimated by
376 the scheduler. The last argument is the distance in cycles
377 between the already scheduled insn (first parameter) and the
378 second insn (second parameter). */
379 bool (* is_costly_dependence) (struct _dep *_dep, int, int);
381 /* Given the current cost, COST, of an insn, INSN, calculate and
382 return a new cost based on its relationship to DEP_INSN through the
383 dependence of type DEP_TYPE. The default is to make no adjustment. */
384 int (* adjust_cost_2) (rtx insn, int, rtx dep_insn, int cost, int dw);
386 /* The following member value is a pointer to a function called
387 by the insn scheduler. This hook is called to notify the backend
388 that new instructions were emitted. */
389 void (* h_i_d_extended) (void);
391 /* Next 5 functions are for multi-point scheduling. */
393 /* Allocate memory for scheduler context. */
394 void *(* alloc_sched_context) (void);
396 /* Fills the context from the local machine scheduler context. */
397 void (* init_sched_context) (void *, bool);
399 /* Sets local machine scheduler context to a saved value. */
400 void (* set_sched_context) (void *);
402 /* Clears a scheduler context so it becomes like after init. */
403 void (* clear_sched_context) (void *);
405 /* Frees the scheduler context. */
406 void (* free_sched_context) (void *);
408 /* The following member value is a pointer to a function called
409 by the insn scheduler.
410 The first parameter is an instruction, the second parameter is the type
411 of the requested speculation, and the third parameter is a pointer to the
412 speculative pattern of the corresponding type (set if return value == 1).
414 -1, if there is no pattern, that will satisfy the requested speculation
416 0, if current pattern satisfies the requested speculation type,
417 1, if pattern of the instruction should be changed to the newly
419 int (* speculate_insn) (rtx, int, rtx *);
421 /* The following member value is a pointer to a function called
422 by the insn scheduler. It should return true if the check instruction
423 passed as the parameter needs a recovery block. */
424 bool (* needs_block_p) (int);
426 /* The following member value is a pointer to a function called
427 by the insn scheduler. It should return a pattern for the check
429 The first parameter is a speculative instruction, the second parameter
430 is the label of the corresponding recovery block (or null, if it is a
431 simple check). If the mutation of the check is requested (e.g. from
432 ld.c to chk.a), the third parameter is true - in this case the first
433 parameter is the previous check. */
434 rtx (* gen_spec_check) (rtx, rtx, int);
436 /* The following member value is a pointer to a function controlling
437 what insns from the ready insn queue will be considered for the
438 multipass insn scheduling. If the hook returns zero for the insn
439 passed as the parameter, the insn will not be chosen to be
440 issued. This hook is used to discard speculative instructions,
441 that stand at the first position of the ready list. */
442 bool (* first_cycle_multipass_dfa_lookahead_guard_spec) (const_rtx);
444 /* The following member value is a pointer to a function that provides
445 information about the speculation capabilities of the target.
446 The parameter is a pointer to spec_info variable. */
447 void (* set_sched_flags) (struct spec_info_def *);
449 /* Return speculation types of the instruction passed as the parameter. */
450 int (* get_insn_spec_ds) (rtx);
452 /* Return speculation types that are checked for the instruction passed as
454 int (* get_insn_checked_ds) (rtx);
456 /* Return bool if rtx scanning should just skip current layer and
457 advance to the inner rtxes. */
458 bool (* skip_rtx_p) (const_rtx);
460 /* The following member value is a pointer to a function that provides
461 information about the target resource-based lower bound which is
462 used by the swing modulo scheduler. The parameter is a pointer
464 int (* sms_res_mii) (struct ddg *);
467 /* Functions relating to vectorization. */
470 /* The following member value is a pointer to a function called
471 by the vectorizer, and return the decl of the target builtin
473 tree (* builtin_mask_for_load) (void);
475 /* Returns a code for builtin that realizes vectorized version of
476 function, or NULL_TREE if not available. */
477 tree (* builtin_vectorized_function) (tree, tree, tree);
479 /* Returns a function declaration for a builtin that realizes the
480 vector conversion, or NULL_TREE if not available. */
481 tree (* builtin_conversion) (unsigned, tree, tree);
483 /* Target builtin that implements vector widening multiplication.
484 builtin_mul_widen_eve computes the element-by-element products
485 for the even elements, and builtin_mul_widen_odd computes the
486 element-by-element products for the odd elements. */
487 tree (* builtin_mul_widen_even) (tree);
488 tree (* builtin_mul_widen_odd) (tree);
490 /* Returns the cost to be added to the overheads involved with
491 executing the vectorized version of a loop. */
492 int (*builtin_vectorization_cost) (bool);
494 /* Return true if vector alignment is reachable (by peeling N
495 iterations) for the given type. */
496 bool (* vector_alignment_reachable) (const_tree, bool);
498 /* Target builtin that implements vector permute. */
499 tree (* builtin_vec_perm) (tree, tree*);
501 /* Return true if a vector created for builtin_vec_perm is valid. */
502 bool (* builtin_vec_perm_ok) (tree, tree);
504 /* Return true if the target supports misaligned store/load of a
505 specific factor denoted in the third parameter. The last parameter
506 is true if the access is defined in a packed struct. */
507 bool (* builtin_support_vector_misalignment) (enum machine_mode,
508 const_tree, int, bool);
511 /* The initial value of target_flags. */
512 int default_target_flags;
514 /* Allow target specific overriding of option settings after options have
515 been changed by an attribute or pragma or when it is reset at the
516 end of the code affected by an attribute or pragma. */
517 void (* override_options_after_change) (void);
519 /* Handle target switch CODE (an OPT_* value). ARG is the argument
520 passed to the switch; it is NULL if no argument was. VALUE is the
521 value of ARG if CODE specifies a UInteger option, otherwise it is
522 1 if the positive form of the switch was used and 0 if the negative
523 form was. Return true if the switch was valid. */
524 bool (* handle_option) (size_t code, const char *arg, int value);
526 /* Display extra, target specific information in response to a
527 --target-help switch. */
528 void (* target_help) (void);
530 /* Return machine mode for filter value. */
531 enum machine_mode (* eh_return_filter_mode) (void);
533 /* Return machine mode for libgcc expanded cmp instructions. */
534 enum machine_mode (* libgcc_cmp_return_mode) (void);
536 /* Return machine mode for libgcc expanded shift instructions. */
537 enum machine_mode (* libgcc_shift_count_mode) (void);
539 /* Return machine mode to be used for _Unwind_Word type. */
540 enum machine_mode (* unwind_word_mode) (void);
542 /* Given two decls, merge their attributes and return the result. */
543 tree (* merge_decl_attributes) (tree, tree);
545 /* Given two types, merge their attributes and return the result. */
546 tree (* merge_type_attributes) (tree, tree);
548 /* Table of machine attributes and functions to handle them.
550 const struct attribute_spec *attribute_table;
552 /* Return true iff attribute NAME expects a plain identifier as its first
554 bool (*attribute_takes_identifier_p) (const_tree name);
556 /* Return zero if the attributes on TYPE1 and TYPE2 are incompatible,
557 one if they are compatible and two if they are nearly compatible
558 (which causes a warning to be generated). */
559 int (* comp_type_attributes) (const_tree type1, const_tree type2);
561 /* Assign default attributes to the newly defined TYPE. */
562 void (* set_default_type_attributes) (tree type);
564 /* Insert attributes on the newly created DECL. */
565 void (* insert_attributes) (tree decl, tree *attributes);
567 /* Return true if FNDECL (which has at least one machine attribute)
568 can be inlined despite its machine attributes, false otherwise. */
569 bool (* function_attribute_inlinable_p) (const_tree fndecl);
571 /* Return true if bitfields in RECORD_TYPE should follow the
572 Microsoft Visual C++ bitfield layout rules. */
573 bool (* ms_bitfield_layout_p) (const_tree record_type);
575 /* True if the target supports decimal floating point. */
576 bool (* decimal_float_supported_p) (void);
578 /* True if the target supports fixed-point. */
579 bool (* fixed_point_supported_p) (void);
581 /* Return true if anonymous bitfields affect structure alignment. */
582 bool (* align_anon_bitfield) (void);
584 /* Return true if volatile bitfields should use the narrowest type possible.
585 Return false if they should use the container type. */
586 bool (* narrow_volatile_bitfield) (void);
588 /* Set up target-specific built-in functions. */
589 void (* init_builtins) (void);
591 /* Initialize (if INITIALIZE_P is true) and return the target-specific
592 built-in function decl for CODE.
593 Return NULL if that is not possible. Return error_mark_node if CODE
594 is outside of the range of valid target builtin function codes. */
595 tree (* builtin_decl) (unsigned code, bool initialize_p);
597 /* Expand a target-specific builtin. */
598 rtx (* expand_builtin) (tree exp, rtx target, rtx subtarget,
599 enum machine_mode mode, int ignore);
601 /* Select a replacement for a target-specific builtin. This is done
602 *before* regular type checking, and so allows the target to
603 implement a crude form of function overloading. The result is a
604 complete expression that implements the operation. PARAMS really
605 has type VEC(tree,gc)*, but we don't want to include tree.h
607 tree (*resolve_overloaded_builtin) (unsigned int /*location_t*/,
608 tree decl, void *params);
610 /* Fold a target-specific builtin. */
611 tree (* fold_builtin) (tree fndecl, tree arglist, bool ignore);
613 /* Returns a code for a target-specific builtin that implements
614 reciprocal of the function, or NULL_TREE if not available. */
615 tree (* builtin_reciprocal) (unsigned, bool, bool);
617 /* For a vendor-specific TYPE, return a pointer to a statically-allocated
618 string containing the C++ mangling for TYPE. In all other cases, return
620 const char * (* mangle_type) (const_tree type);
622 /* Make any adjustments to libfunc names needed for this target. */
623 void (* init_libfuncs) (void);
625 /* Given a decl, a section name, and whether the decl initializer
626 has relocs, choose attributes for the section. */
627 /* ??? Should be merged with SELECT_SECTION and UNIQUE_SECTION. */
628 unsigned int (* section_type_flags) (tree, const char *, int);
630 /* True if new jumps cannot be created, to replace existing ones or
631 not, at the current point in the compilation. */
632 bool (* cannot_modify_jumps_p) (void);
634 /* Return a register class for which branch target register
635 optimizations should be applied. */
636 enum reg_class (* branch_target_register_class) (void);
638 /* Return true if branch target register optimizations should include
639 callee-saved registers that are not already live during the current
640 function. AFTER_PE_GEN is true if prologues and epilogues have
641 already been generated. */
642 bool (* branch_target_register_callee_saved) (bool after_pe_gen);
644 /* Return true if the target supports conditional execution. */
645 bool (* have_conditional_execution) (void);
647 /* Return a new value for loop unroll size. */
648 unsigned (* loop_unroll_adjust) (unsigned nunroll, struct loop *loop);
650 /* True if the constant X cannot be placed in the constant pool. */
651 bool (* cannot_force_const_mem) (rtx);
653 /* True if the insn X cannot be duplicated. */
654 bool (* cannot_copy_insn_p) (rtx);
656 /* True if X is considered to be commutative. */
657 bool (* commutative_p) (const_rtx, int);
659 /* Given an invalid address X for a given machine mode, try machine-specific
660 ways to make it legitimate. Return X or an invalid address on failure. */
661 rtx (* legitimize_address) (rtx, rtx, enum machine_mode);
663 /* Given an address RTX, undo the effects of LEGITIMIZE_ADDRESS. */
664 rtx (* delegitimize_address) (rtx);
666 /* Given an address RTX, say whether it is valid. */
667 bool (* legitimate_address_p) (enum machine_mode, rtx, bool);
669 /* True if the given constant can be put into an object_block. */
670 bool (* use_blocks_for_constant_p) (enum machine_mode, const_rtx);
672 /* The minimum and maximum byte offsets for anchored addresses. */
673 HOST_WIDE_INT min_anchor_offset;
674 HOST_WIDE_INT max_anchor_offset;
676 /* True if section anchors can be used to access the given symbol. */
677 bool (* use_anchors_for_symbol_p) (const_rtx);
679 /* True if it is OK to do sibling call optimization for the specified
680 call expression EXP. DECL will be the called function, or NULL if
681 this is an indirect call. */
682 bool (*function_ok_for_sibcall) (tree decl, tree exp);
684 /* Establish appropriate back-end context for processing the function
685 FNDECL. The argument might be NULL to indicate processing at top
686 level, outside of any function scope. */
687 void (*set_current_function) (tree fndecl);
689 /* True if EXP should be placed in a "small data" section. */
690 bool (* in_small_data_p) (const_tree);
692 /* True if EXP names an object for which name resolution must resolve
693 to the current executable or shared library. */
694 bool (* binds_local_p) (const_tree);
696 /* Modify and return the identifier of a DECL's external name,
697 originally identified by ID, as required by the target,
698 (eg, append @nn to windows32 stdcall function names).
699 The default is to return ID without modification. */
700 tree (* mangle_decl_assembler_name) (tree decl, tree id);
702 /* Do something target-specific to record properties of the DECL into
703 the associated SYMBOL_REF. */
704 void (* encode_section_info) (tree, rtx, int);
706 /* Undo the effects of encode_section_info on the symbol string. */
707 const char * (* strip_name_encoding) (const char *);
709 /* If shift optabs for MODE are known to always truncate the shift count,
710 return the mask that they apply. Return 0 otherwise. */
711 unsigned HOST_WIDE_INT (* shift_truncation_mask) (enum machine_mode mode);
713 /* Return the number of divisions in the given MODE that should be present,
714 so that it is profitable to turn the division into a multiplication by
716 unsigned int (* min_divisions_for_recip_mul) (enum machine_mode mode);
718 /* If the representation of integral MODE is such that values are
719 always sign-extended to a wider mode MODE_REP then return
720 SIGN_EXTEND. Return UNKNOWN otherwise. */
721 /* Note that the return type ought to be RTX_CODE, but that's not
722 necessarily defined at this point. */
723 int (* mode_rep_extended) (enum machine_mode mode,
724 enum machine_mode mode_rep);
726 /* True if MODE is valid for a pointer in __attribute__((mode("MODE"))). */
727 bool (* valid_pointer_mode) (enum machine_mode mode);
729 /* Support for named address spaces. */
731 /* MODE to use for a pointer into another address space. */
732 enum machine_mode (* pointer_mode) (addr_space_t);
734 /* MODE to use for an address in another address space. */
735 enum machine_mode (* address_mode) (addr_space_t);
737 /* True if MODE is valid for a pointer in __attribute__((mode("MODE")))
738 in another address space. */
739 bool (* valid_pointer_mode) (enum machine_mode, addr_space_t);
741 /* True if an address is a valid memory address to a given named address
742 space for a given mode. */
743 bool (* legitimate_address_p) (enum machine_mode, rtx, bool, addr_space_t);
745 /* Return an updated address to convert an invalid pointer to a named
746 address space to a valid one. If NULL_RTX is returned use machine
747 independent methods to make the address valid. */
748 rtx (* legitimize_address) (rtx, rtx, enum machine_mode, addr_space_t);
750 /* True if one named address space is a subset of another named address. */
751 bool (* subset_p) (addr_space_t, addr_space_t);
753 /* Function to convert an rtl expression from one address space to
755 rtx (* convert) (rtx, tree, tree);
759 /* True if MODE is valid for the target. By "valid", we mean able to
760 be manipulated in non-trivial ways. In particular, this means all
761 the arithmetic is supported. */
762 bool (* scalar_mode_supported_p) (enum machine_mode mode);
764 /* Similarly for vector modes. "Supported" here is less strict. At
765 least some operations are supported; need to check optabs or builtins
766 for further details. */
767 bool (* vector_mode_supported_p) (enum machine_mode mode);
769 /* True for MODE if the target expects that registers in this mode will
770 be allocated to registers in a small register class. The compiler is
771 allowed to use registers explicitly used in the rtl as spill registers
772 but it should prevent extending the lifetime of these registers. */
773 bool (* small_register_classes_for_mode_p) (enum machine_mode mode);
775 /* Compute a (partial) cost for rtx X. Return true if the complete
776 cost has been computed, and false if subexpressions should be
777 scanned. In either case, *TOTAL contains the cost result. */
778 /* Note that CODE and OUTER_CODE ought to be RTX_CODE, but that's
779 not necessarily defined at this point. */
780 bool (* rtx_costs) (rtx x, int code, int outer_code, int *total, bool speed);
782 /* Compute the cost of X, used as an address. Never called with
783 invalid addresses. */
784 int (* address_cost) (rtx x, bool speed);
786 /* Return where to allocate pseudo for a given hard register initial
788 rtx (* allocate_initial_value) (rtx x);
790 /* Return nonzero if evaluating UNSPEC[_VOLATILE] X might cause a trap.
791 FLAGS has the same meaning as in rtlanal.c: may_trap_p_1. */
792 int (* unspec_may_trap_p) (const_rtx x, unsigned flags);
794 /* Given a register, this hook should return a parallel of registers
795 to represent where to find the register pieces. Define this hook
796 if the register and its mode are represented in Dwarf in
797 non-contiguous locations, or if the register should be
798 represented in more than one register in Dwarf. Otherwise, this
799 hook should return NULL_RTX. */
800 rtx (* dwarf_register_span) (rtx);
802 /* If expand_builtin_init_dwarf_reg_sizes needs to fill in table
803 entries not corresponding directly to registers below
804 FIRST_PSEUDO_REGISTER, this hook should generate the necessary
805 code, given the address of the table. */
806 void (* init_dwarf_reg_sizes_extra) (tree);
808 /* Fetch the fixed register(s) which hold condition codes, for
809 targets where it makes sense to look for duplicate assignments to
810 the condition codes. This should return true if there is such a
811 register, false otherwise. The arguments should be set to the
812 fixed register numbers. Up to two condition code registers are
813 supported. If there is only one for this target, the int pointed
814 at by the second argument should be set to -1. */
815 bool (* fixed_condition_code_regs) (unsigned int *, unsigned int *);
817 /* If two condition code modes are compatible, return a condition
818 code mode which is compatible with both, such that a comparison
819 done in the returned mode will work for both of the original
820 modes. If the condition code modes are not compatible, return
822 enum machine_mode (* cc_modes_compatible) (enum machine_mode,
825 /* Do machine-dependent code transformations. Called just before
826 delayed-branch scheduling. */
827 void (* machine_dependent_reorg) (void);
829 /* Create the __builtin_va_list type. */
830 tree (* build_builtin_va_list) (void);
832 /* Get the cfun/fndecl calling abi __builtin_va_list type. */
833 tree (* fn_abi_va_list) (tree);
835 /* Get the __builtin_va_list type dependent on input type. */
836 tree (* canonical_va_list_type) (tree);
838 /* Expand the __builtin_va_start builtin. */
839 void (* expand_builtin_va_start) (tree valist, rtx nextarg);
841 /* Gimplifies a VA_ARG_EXPR. */
842 tree (* gimplify_va_arg_expr) (tree valist, tree type, gimple_seq *pre_p,
845 /* Validity-checking routines for PCH files, target-specific.
846 get_pch_validity returns a pointer to the data to be stored,
847 and stores the size in its argument. pch_valid_p gets the same
848 information back and returns NULL if the PCH is valid,
849 or an error message if not.
851 void * (* get_pch_validity) (size_t *);
852 const char * (* pch_valid_p) (const void *, size_t);
854 /* If nonnull, this function checks whether a PCH file with the
855 given set of target flags can be used. It returns NULL if so,
856 otherwise it returns an error message. */
857 const char *(*check_pch_target_flags) (int);
859 /* True if the compiler should give an enum type only as many
860 bytes as it takes to represent the range of possible values of
862 bool (* default_short_enums) (void);
864 /* This target hook returns an rtx that is used to store the address
865 of the current frame into the built-in setjmp buffer. */
866 rtx (* builtin_setjmp_frame_value) (void);
868 /* This target hook should add STRING_CST trees for any hard regs
869 the port wishes to automatically clobber for an asm. */
870 tree (* md_asm_clobbers) (tree, tree, tree);
872 /* This target hook allows the backend to specify a calling convention
873 in the debug information. This function actually returns an
874 enum dwarf_calling_convention, but because of forward declarations
875 and not wanting to include dwarf2.h everywhere target.h is included
876 the function is being declared as an int. */
877 int (* dwarf_calling_convention) (const_tree);
879 /* This target hook allows the backend to emit frame-related insns that
880 contain UNSPECs or UNSPEC_VOLATILEs. The call frame debugging info
881 engine will invoke it on insns of the form
882 (set (reg) (unspec [...] UNSPEC_INDEX))
884 (set (reg) (unspec_volatile [...] UNSPECV_INDEX))
885 to let the backend emit the call frame instructions. */
886 void (* dwarf_handle_frame_unspec) (const char *, rtx, int);
888 /* Perform architecture specific checking of statements gimplified
889 from VA_ARG_EXPR. STMT is the statement. Returns true if the statement
890 doesn't need to be checked for va_list references. */
891 bool (* stdarg_optimize_hook) (struct stdarg_info *ai, const_gimple stmt);
893 /* This target hook allows the operating system to override the DECL
894 that represents the external variable that contains the stack
895 protection guard variable. The type of this DECL is ptr_type_node. */
896 tree (* stack_protect_guard) (void);
898 /* This target hook allows the operating system to override the CALL_EXPR
899 that is invoked when a check vs the guard variable fails. */
900 tree (* stack_protect_fail) (void);
902 /* Returns NULL if target supports the insn within a doloop block,
903 otherwise it returns an error message. */
904 const char * (*invalid_within_doloop) (const_rtx);
906 /* DECL is a variable or function with __attribute__((dllimport))
907 specified. Use this hook if the target needs to add extra validation
908 checks to handle_dll_attribute (). */
909 bool (* valid_dllimport_attribute_p) (const_tree decl);
911 /* If non-zero, align constant anchors in CSE to a multiple of this
913 unsigned HOST_WIDE_INT const_anchor;
915 /* Functions relating to calls - argument passing, returns, etc. */
917 enum machine_mode (*promote_function_mode) (const_tree type,
918 enum machine_mode mode,
922 bool (*promote_prototypes) (const_tree fntype);
923 rtx (*struct_value_rtx) (tree fndecl, int incoming);
924 bool (*return_in_memory) (const_tree type, const_tree fndecl);
925 bool (*return_in_msb) (const_tree type);
927 /* Return true if a parameter must be passed by reference. TYPE may
928 be null if this is a libcall. CA may be null if this query is
929 from __builtin_va_arg. */
930 bool (*pass_by_reference) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
931 const_tree type, bool named_arg);
933 rtx (*expand_builtin_saveregs) (void);
934 /* Returns pretend_argument_size. */
935 void (*setup_incoming_varargs) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
936 tree type, int *pretend_arg_size,
938 bool (*strict_argument_naming) (CUMULATIVE_ARGS *ca);
939 /* Returns true if we should use
940 targetm.calls.setup_incoming_varargs() and/or
941 targetm.calls.strict_argument_naming(). */
942 bool (*pretend_outgoing_varargs_named) (CUMULATIVE_ARGS *ca);
944 /* Given a complex type T, return true if a parameter of type T
945 should be passed as two scalars. */
946 bool (* split_complex_arg) (const_tree type);
948 /* Return true if type T, mode MODE, may not be passed in registers,
949 but must be passed on the stack. */
950 /* ??? This predicate should be applied strictly after pass-by-reference.
951 Need audit to verify that this is the case. */
952 bool (* must_pass_in_stack) (enum machine_mode mode, const_tree t);
954 /* Return true if type TYPE, mode MODE, which is passed by reference,
955 should have the object copy generated by the callee rather than
956 the caller. It is never called for TYPE requiring constructors. */
957 bool (* callee_copies) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
958 const_tree type, bool named);
960 /* Return zero for arguments passed entirely on the stack or entirely
961 in registers. If passed in both, return the number of bytes passed
962 in registers; the balance is therefore passed on the stack. */
963 int (* arg_partial_bytes) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
964 tree type, bool named);
966 /* Return the diagnostic message string if function without a prototype
967 is not allowed for this 'val' argument; NULL otherwise. */
968 const char *(*invalid_arg_for_unprototyped_fn) (const_tree typelist,
972 /* Return an rtx for the return value location of the function
973 specified by FN_DECL_OR_TYPE with a return type of RET_TYPE. */
974 rtx (*function_value) (const_tree ret_type, const_tree fn_decl_or_type,
977 /* Return the rtx for the result of a libcall of mode MODE,
978 calling the function FN_NAME. */
979 rtx (*libcall_value) (enum machine_mode, const_rtx);
981 /* Return true if REGNO is a possible register number for
982 a function value as seen by the caller. */
983 bool (*function_value_regno_p) (const unsigned int);
985 /* Return an rtx for the argument pointer incoming to the
987 rtx (*internal_arg_pointer) (void);
989 /* Update the current function stack boundary if needed. */
990 void (*update_stack_boundary) (void);
992 /* Handle stack alignment and return an rtx for Dynamic Realign
993 Argument Pointer if necessary. */
994 rtx (*get_drap_rtx) (void);
996 /* Return true if all function parameters should be spilled to the
998 bool (*allocate_stack_slots_for_args) (void);
1000 /* Return an rtx for the static chain for FNDECL. If INCOMING_P is true,
1001 then it should be for the callee; otherwise for the caller. */
1002 rtx (*static_chain) (const_tree fndecl, bool incoming_p);
1004 /* Fill in the trampoline at MEM with a call to FNDECL and a
1005 static chain value of CHAIN. */
1006 void (*trampoline_init) (rtx mem, tree fndecl, rtx chain);
1008 /* Adjust the address of the trampoline in a target-specific way. */
1009 rtx (*trampoline_adjust_address) (rtx addr);
1012 /* Return the diagnostic message string if conversion from FROMTYPE
1013 to TOTYPE is not allowed, NULL otherwise. */
1014 const char *(*invalid_conversion) (const_tree fromtype, const_tree totype);
1016 /* Return the diagnostic message string if the unary operation OP is
1017 not permitted on TYPE, NULL otherwise. */
1018 const char *(*invalid_unary_op) (int op, const_tree type);
1020 /* Return the diagnostic message string if the binary operation OP
1021 is not permitted on TYPE1 and TYPE2, NULL otherwise. */
1022 const char *(*invalid_binary_op) (int op, const_tree type1, const_tree type2);
1024 /* Return the diagnostic message string if TYPE is not valid as a
1025 function parameter type, NULL otherwise. */
1026 const char *(*invalid_parameter_type) (const_tree type);
1028 /* Return the diagnostic message string if TYPE is not valid as a
1029 function return type, NULL otherwise. */
1030 const char *(*invalid_return_type) (const_tree type);
1032 /* If values of TYPE are promoted to some other type when used in
1033 expressions (analogous to the integer promotions), return that type,
1034 or NULL_TREE otherwise. */
1035 tree (*promoted_type) (const_tree type);
1037 /* Convert EXPR to TYPE, if target-specific types with special conversion
1038 rules are involved. Return the converted expression, or NULL to apply
1039 the standard conversion rules. */
1040 tree (*convert_to_type) (tree type, tree expr);
1042 /* Return the array of IRA cover classes for the current target. */
1043 const enum reg_class *(*ira_cover_classes) (void);
1045 /* Return the class for a secondary reload, and fill in extra information. */
1046 enum reg_class (*secondary_reload) (bool, rtx, enum reg_class,
1048 secondary_reload_info *);
1050 /* This target hook allows the backend to perform additional
1051 processing while initializing for variable expansion. */
1052 void (* expand_to_rtl_hook) (void);
1054 /* This target hook allows the backend to perform additional
1055 instantiations on rtx that are not actually in insns yet,
1056 but will be later. */
1057 void (* instantiate_decls) (void);
1059 /* Return true if is OK to use a hard register REGNO as scratch register
1061 bool (* hard_regno_scratch_ok) (unsigned int regno);
1063 /* Return the smallest number of different values for which it is best to
1064 use a jump-table instead of a tree of conditional branches. */
1065 unsigned int (* case_values_threshold) (void);
1067 /* Retutn true if a function must have and use a frame pointer. */
1068 bool (* frame_pointer_required) (void);
1070 /* Returns true if the compiler is allowed to try to replace register number
1071 from-reg with register number to-reg. */
1072 bool (* can_eliminate) (const int, const int);
1074 /* Functions specific to the C family of frontends. */
1076 /* Return machine mode for non-standard suffix
1077 or VOIDmode if non-standard suffixes are unsupported. */
1078 enum machine_mode (*mode_for_suffix) (char);
1081 /* Functions specific to the C++ frontend. */
1083 /* Return the integer type used for guard variables. */
1084 tree (*guard_type) (void);
1085 /* Return true if only the low bit of the guard should be tested. */
1086 bool (*guard_mask_bit) (void);
1087 /* Returns the size of the array cookie for an array of type. */
1088 tree (*get_cookie_size) (tree);
1089 /* Returns true if the element size should be stored in the
1091 bool (*cookie_has_size) (void);
1092 /* Allows backends to perform additional processing when
1093 deciding if a class should be exported or imported. */
1094 int (*import_export_class) (tree, int);
1095 /* Returns true if constructors and destructors return "this". */
1096 bool (*cdtor_returns_this) (void);
1097 /* Returns true if the key method for a class can be an inline
1098 function, so long as it is not declared inline in the class
1099 itself. Returning true is the behavior required by the Itanium
1101 bool (*key_method_may_be_inline) (void);
1102 /* DECL is a virtual table, virtual table table, typeinfo object,
1103 or other similar implicit class data object that will be
1104 emitted with external linkage in this translation unit. No ELF
1105 visibility has been explicitly specified. If the target needs
1106 to specify a visibility other than that of the containing class,
1107 use this hook to set DECL_VISIBILITY and
1108 DECL_VISIBILITY_SPECIFIED. */
1109 void (*determine_class_data_visibility) (tree decl);
1110 /* Returns true (the default) if virtual tables and other
1111 similar implicit class data objects are always COMDAT if they
1112 have external linkage. If this hook returns false, then
1113 class data for classes whose virtual table will be emitted in
1114 only one translation unit will not be COMDAT. */
1115 bool (*class_data_always_comdat) (void);
1116 /* Returns true (the default) if the RTTI for the basic types,
1117 which is always defined in the C++ runtime, should be COMDAT;
1118 false if it should not be COMDAT. */
1119 bool (*library_rtti_comdat) (void);
1120 /* Returns true if __aeabi_atexit should be used to register static
1122 bool (*use_aeabi_atexit) (void);
1123 /* Returns true if target may use atexit in the same manner as
1124 __cxa_atexit to register static destructors. */
1125 bool (*use_atexit_for_cxa_atexit) (void);
1126 /* TYPE is a C++ class (i.e., RECORD_TYPE or UNION_TYPE) that
1127 has just been defined. Use this hook to make adjustments to the
1128 class (eg, tweak visibility or perform any other required
1129 target modifications). */
1130 void (*adjust_class_at_definition) (tree type);
1133 /* Functions and data for emulated TLS support. */
1135 /* Name of the address and common functions. */
1136 const char *get_address;
1137 const char *register_common;
1139 /* Prefixes for proxy variable and template. */
1140 const char *var_section;
1141 const char *tmpl_section;
1143 /* Prefixes for proxy variable and template. */
1144 const char *var_prefix;
1145 const char *tmpl_prefix;
1147 /* Function to generate field definitions of the proxy variable. */
1148 tree (*var_fields) (tree, tree *);
1150 /* Function to initialize a proxy variable. */
1151 tree (*var_init) (tree, tree, tree);
1153 /* Whether we are allowed to alter the usual alignment of the
1155 bool var_align_fixed;
1157 /* Whether we can emit debug information for TLS vars. */
1158 bool debug_form_tls_address;
1161 struct target_option_hooks {
1162 /* Function to validate the attribute((option(...))) strings or NULL. If
1163 the option is validated, it is assumed that DECL_FUNCTION_SPECIFIC will
1164 be filled in in the function decl node. */
1165 bool (*valid_attribute_p) (tree, tree, tree, int);
1167 /* Function to save any extra target state in the target options
1169 void (*save) (struct cl_target_option *);
1171 /* Function to restore any extra target state from the target options
1173 void (*restore) (struct cl_target_option *);
1175 /* Function to print any extra target state from the target options
1177 void (*print) (FILE *, int, struct cl_target_option *);
1179 /* Function to parse arguments to be validated for #pragma option, and to
1180 change the state if the options are valid. If the first argument is
1181 NULL, the second argument specifies the default options to use. Return
1182 true if the options are valid, and set the current state. */
1183 bool (*pragma_parse) (tree, tree);
1185 /* Function to determine if one function can inline another function. */
1186 bool (*can_inline_p) (tree, tree);
1189 /* For targets that need to mark extra registers as live on entry to
1190 the function, they should define this target hook and set their
1191 bits in the bitmap passed in. */
1192 void (*live_on_entry) (bitmap);
1194 /* True if unwinding tables should be generated by default. */
1195 bool unwind_tables_default;
1197 /* Leave the boolean fields at the end. */
1199 /* True if arbitrary sections are supported. */
1200 bool have_named_sections;
1202 /* True if we can create zeroed data by switching to a BSS section
1203 and then using ASM_OUTPUT_SKIP to allocate the space. */
1204 bool have_switchable_bss_sections;
1206 /* True if "native" constructors and destructors are supported,
1207 false if we're using collect2 for the job. */
1208 bool have_ctors_dtors;
1210 /* True if thread-local storage is supported. */
1213 /* True if a small readonly data section is supported. */
1214 bool have_srodata_section;
1216 /* True if EH frame info sections should be zero-terminated. */
1217 bool terminate_dw2_eh_frame_info;
1219 /* True if #NO_APP should be emitted at the beginning of
1221 bool file_start_app_off;
1223 /* True if output_file_directive should be called for main_input_filename
1224 at the beginning of assembly output. */
1225 bool file_start_file_directive;
1227 /* True if #pragma extern_prefix is to be supported. */
1228 bool handle_pragma_extern_prefix;
1230 /* True if the target is allowed to reorder memory accesses unless
1231 synchronization is explicitly requested. */
1232 bool relaxed_ordering;
1234 /* Returns true if we should generate exception tables for use with the
1235 ARM EABI. The effects the encoding of function exception specifications.
1237 bool arm_eabi_unwinder;
1239 /* Leave the boolean fields at the end. */
1242 extern struct gcc_target targetm;
1244 struct gcc_targetcm {
1245 /* Handle target switch CODE (an OPT_* value). ARG is the argument
1246 passed to the switch; it is NULL if no argument was. VALUE is the
1247 value of ARG if CODE specifies a UInteger option, otherwise it is
1248 1 if the positive form of the switch was used and 0 if the negative
1249 form was. Return true if the switch was valid. */
1250 bool (*handle_c_option) (size_t code, const char *arg, int value);
1253 /* Each target can provide their own. */
1254 extern struct gcc_targetcm targetcm;
1256 #endif /* GCC_TARGET_H */
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