1 /* Data structure definitions for a generic GCC target.
2 Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
3 Free Software Foundation, Inc.
5 This program is free software; you can redistribute it and/or modify it
6 under the terms of the GNU General Public License as published by the
7 Free Software Foundation; either version 3, or (at your option) any
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with this program; see the file COPYING3. If not see
17 <http://www.gnu.org/licenses/>.
19 In other words, you are welcome to use, share and improve this program.
20 You are forbidden to forbid anyone else to use, share and improve
21 what you give them. Help stamp out software-hoarding! */
24 /* This file contains a data structure that describes a GCC target.
25 At present it is incomplete, but in future it should grow to
26 contain most or all target machine and target O/S specific
29 This structure has its initializer declared in target-def.h in the
30 form of large macro TARGET_INITIALIZER that expands to many smaller
33 The smaller macros each initialize one component of the structure,
34 and each has a default. Each target should have a file that
35 includes target.h and target-def.h, and overrides any inappropriate
36 defaults by undefining the relevant macro and defining a suitable
37 replacement. That file should then contain the definition of
40 struct gcc_target targetm = TARGET_INITIALIZER;
42 Doing things this way allows us to bring together everything that
43 defines a GCC target. By supplying a default that is appropriate
44 to most targets, we can easily add new items without needing to
45 edit dozens of target configuration files. It should also allow us
46 to gradually reduce the amount of conditional compilation that is
47 scattered throughout GCC. */
53 #include "insn-modes.h"
55 /* Types used by the record_gcc_switches() target function. */
58 SWITCH_TYPE_PASSED, /* A switch passed on the command line. */
59 SWITCH_TYPE_ENABLED, /* An option that is currently enabled. */
60 SWITCH_TYPE_DESCRIPTIVE, /* Descriptive text, not a switch or option. */
61 SWITCH_TYPE_LINE_START, /* Please emit any necessary text at the start of a line. */
62 SWITCH_TYPE_LINE_END /* Please emit a line terminator. */
66 typedef int (* print_switch_fn_type) (print_switch_type, const char *);
68 /* An example implementation for ELF targets. Defined in varasm.c */
69 extern int elf_record_gcc_switches (print_switch_type type, const char *);
74 /* The struct used by the secondary_reload target hook. */
75 typedef struct secondary_reload_info
77 /* icode is actually an enum insn_code, but we don't want to force every
78 file that includes target.h to include optabs.h . */
80 int extra_cost; /* Cost for using (a) scratch register(s) to be taken
81 into account by copy_cost. */
82 /* The next two members are for the use of the backward
83 compatibility hook. */
84 struct secondary_reload_info *prev_sri;
85 int t_icode; /* Actually an enum insn_code - see above. */
86 } secondary_reload_info;
88 /* This is defined in sched-int.h . */
91 /* This is defined in ddg.h . */
94 /* Assembler instructions for creating various kinds of integer object. */
104 /* The target structure. This holds all the backend hooks. */
108 /* Functions that output assembler for the target. */
111 /* Opening and closing parentheses for asm expression grouping. */
112 const char *open_paren, *close_paren;
114 /* Assembler instructions for creating various kinds of integer object. */
116 struct asm_int_op aligned_op, unaligned_op;
118 /* Try to output the assembler code for an integer object whose
119 value is given by X. SIZE is the size of the object in bytes and
120 ALIGNED_P indicates whether it is aligned. Return true if
121 successful. Only handles cases for which BYTE_OP, ALIGNED_OP
122 and UNALIGNED_OP are NULL. */
123 bool (* integer) (rtx x, unsigned int size, int aligned_p);
125 /* Output code that will globalize a label. */
126 void (* globalize_label) (FILE *, const char *);
128 /* Output code that will globalize a declaration. */
129 void (* globalize_decl_name) (FILE *, tree);
131 /* Output code that will emit a label for unwind info, if this
132 target requires such labels. Second argument is the decl the
133 unwind info is associated with, third is a boolean: true if
134 this is for exception handling, fourth is a boolean: true if
135 this is only a placeholder for an omitted FDE. */
136 void (* unwind_label) (FILE *, tree, int, int);
138 /* Output code that will emit a label to divide up the exception
140 void (* except_table_label) (FILE *);
142 /* Emit any directives required to unwind this instruction. */
143 void (* unwind_emit) (FILE *, rtx);
145 /* Output an internal label. */
146 void (* internal_label) (FILE *, const char *, unsigned long);
148 /* Emit a ttype table reference to a typeinfo object. */
149 bool (* ttype) (rtx);
151 /* Emit an assembler directive to set visibility for the symbol
152 associated with the tree decl. */
153 void (* visibility) (tree, int);
155 /* Output the assembler code for entry to a function. */
156 void (* function_prologue) (FILE *, HOST_WIDE_INT);
158 /* Output the assembler code for end of prologue. */
159 void (* function_end_prologue) (FILE *);
161 /* Output the assembler code for start of epilogue. */
162 void (* function_begin_epilogue) (FILE *);
164 /* Output the assembler code for function exit. */
165 void (* function_epilogue) (FILE *, HOST_WIDE_INT);
167 /* Initialize target-specific sections. */
168 void (* init_sections) (void);
170 /* Tell assembler to change to section NAME with attributes FLAGS.
171 If DECL is non-NULL, it is the VAR_DECL or FUNCTION_DECL with
172 which this section is associated. */
173 void (* named_section) (const char *name, unsigned int flags, tree decl);
175 /* Return a mask describing how relocations should be treated when
176 selecting sections. Bit 1 should be set if global relocations
177 should be placed in a read-write section; bit 0 should be set if
178 local relocations should be placed in a read-write section. */
179 int (*reloc_rw_mask) (void);
181 /* Return a section for EXP. It may be a DECL or a constant. RELOC
182 is nonzero if runtime relocations must be applied; bit 1 will be
183 set if the runtime relocations require non-local name resolution.
184 ALIGN is the required alignment of the data. */
185 section *(* select_section) (tree, int, unsigned HOST_WIDE_INT);
187 /* Return a section for X. MODE is X's mode and ALIGN is its
188 alignment in bits. */
189 section *(* select_rtx_section) (enum machine_mode, rtx,
190 unsigned HOST_WIDE_INT);
192 /* Select a unique section name for DECL. RELOC is the same as
193 for SELECT_SECTION. */
194 void (* unique_section) (tree, int);
196 /* Return the readonly data section associated with function DECL. */
197 section *(* function_rodata_section) (tree);
199 /* Output a constructor for a symbol with a given priority. */
200 void (* constructor) (rtx, int);
202 /* Output a destructor for a symbol with a given priority. */
203 void (* destructor) (rtx, int);
205 /* Output the assembler code for a thunk function. THUNK_DECL is the
206 declaration for the thunk function itself, FUNCTION is the decl for
207 the target function. DELTA is an immediate constant offset to be
208 added to THIS. If VCALL_OFFSET is nonzero, the word at
209 *(*this + vcall_offset) should be added to THIS. */
210 void (* output_mi_thunk) (FILE *file, tree thunk_decl,
211 HOST_WIDE_INT delta, HOST_WIDE_INT vcall_offset,
214 /* Determine whether output_mi_thunk would succeed. */
215 /* ??? Ideally, this hook would not exist, and success or failure
216 would be returned from output_mi_thunk directly. But there's
217 too much undo-able setup involved in invoking output_mi_thunk.
218 Could be fixed by making output_mi_thunk emit rtl instead of
219 text to the output file. */
220 bool (* can_output_mi_thunk) (const_tree thunk_decl, HOST_WIDE_INT delta,
221 HOST_WIDE_INT vcall_offset,
222 const_tree function_decl);
224 /* Output any boilerplate text needed at the beginning of a
226 void (*file_start) (void);
228 /* Output any boilerplate text needed at the end of a
230 void (*file_end) (void);
232 /* Output an assembler pseudo-op to declare a library function name
234 void (*external_libcall) (rtx);
236 /* Output an assembler directive to mark decl live. This instructs
237 linker to not dead code strip this symbol. */
238 void (*mark_decl_preserved) (const char *);
240 /* Output a record of the command line switches that have been passed. */
241 print_switch_fn_type record_gcc_switches;
242 /* The name of the section that the example ELF implementation of
243 record_gcc_switches will use to store the information. Target
244 specific versions of record_gcc_switches may or may not use
246 const char * record_gcc_switches_section;
248 /* Output the definition of a section anchor. */
249 void (*output_anchor) (rtx);
251 /* Output a DTP-relative reference to a TLS symbol. */
252 void (*output_dwarf_dtprel) (FILE *file, int size, rtx x);
254 /* Some target machines need to postscan each insn after it is output. */
255 void (*final_postscan_insn) (FILE *, rtx, rtx *, int);
258 /* Functions relating to instruction scheduling. */
261 /* Given the current cost, COST, of an insn, INSN, calculate and
262 return a new cost based on its relationship to DEP_INSN through
263 the dependence LINK. The default is to make no adjustment. */
264 int (* adjust_cost) (rtx insn, rtx link, rtx dep_insn, int cost);
266 /* Adjust the priority of an insn as you see fit. Returns the new
268 int (* adjust_priority) (rtx, int);
270 /* Function which returns the maximum number of insns that can be
271 scheduled in the same machine cycle. This must be constant
272 over an entire compilation. The default is 1. */
273 int (* issue_rate) (void);
275 /* Calculate how much this insn affects how many more insns we
276 can emit this cycle. Default is they all cost the same. */
277 int (* variable_issue) (FILE *, int, rtx, int);
279 /* Initialize machine-dependent scheduling code. */
280 void (* md_init) (FILE *, int, int);
282 /* Finalize machine-dependent scheduling code. */
283 void (* md_finish) (FILE *, int);
285 /* Initialize machine-dependent function wide scheduling code. */
286 void (* md_init_global) (FILE *, int, int);
288 /* Finalize machine-dependent function wide scheduling code. */
289 void (* md_finish_global) (FILE *, int);
291 /* Reorder insns in a machine-dependent fashion, in two different
292 places. Default does nothing. */
293 int (* reorder) (FILE *, int, rtx *, int *, int);
294 int (* reorder2) (FILE *, int, rtx *, int *, int);
296 /* The following member value is a pointer to a function called
297 after evaluation forward dependencies of insns in chain given
298 by two parameter values (head and tail correspondingly). */
299 void (* dependencies_evaluation_hook) (rtx, rtx);
301 /* The values of the following four members are pointers to
302 functions used to simplify the automaton descriptions.
303 dfa_pre_cycle_insn and dfa_post_cycle_insn give functions
304 returning insns which are used to change the pipeline hazard
305 recognizer state when the new simulated processor cycle
306 correspondingly starts and finishes. The function defined by
307 init_dfa_pre_cycle_insn and init_dfa_post_cycle_insn are used
308 to initialize the corresponding insns. The default values of
309 the members result in not changing the automaton state when
310 the new simulated processor cycle correspondingly starts and
312 void (* init_dfa_pre_cycle_insn) (void);
313 rtx (* dfa_pre_cycle_insn) (void);
314 void (* init_dfa_post_cycle_insn) (void);
315 rtx (* dfa_post_cycle_insn) (void);
317 /* The values of the following two members are pointers to
318 functions used to simplify the automaton descriptions.
319 dfa_pre_advance_cycle and dfa_post_advance_cycle are getting called
320 immediately before and after cycle is advanced. */
321 void (* dfa_pre_advance_cycle) (void);
322 void (* dfa_post_advance_cycle) (void);
324 /* The following member value is a pointer to a function returning value
325 which defines how many insns in queue `ready' will we try for
326 multi-pass scheduling. If the member value is nonzero and the
327 function returns positive value, the DFA based scheduler will make
328 multi-pass scheduling for the first cycle. In other words, we will
329 try to choose ready insn which permits to start maximum number of
330 insns on the same cycle. */
331 int (* first_cycle_multipass_dfa_lookahead) (void);
333 /* The following member value is pointer to a function controlling
334 what insns from the ready insn queue will be considered for the
335 multipass insn scheduling. If the hook returns zero for insn
336 passed as the parameter, the insn will be not chosen to be
338 int (* first_cycle_multipass_dfa_lookahead_guard) (rtx);
340 /* The following member value is pointer to a function called by
341 the insn scheduler before issuing insn passed as the third
342 parameter on given cycle. If the hook returns nonzero, the
343 insn is not issued on given processors cycle. Instead of that,
344 the processor cycle is advanced. If the value passed through
345 the last parameter is zero, the insn ready queue is not sorted
346 on the new cycle start as usually. The first parameter passes
347 file for debugging output. The second one passes the scheduler
348 verbose level of the debugging output. The forth and the fifth
349 parameter values are correspondingly processor cycle on which
350 the previous insn has been issued and the current processor
352 int (* dfa_new_cycle) (FILE *, int, rtx, int, int, int *);
354 /* The following member value is a pointer to a function called by the
355 insn scheduler. It should return true if there exists a dependence
356 which is considered costly by the target, between the insn
357 DEP_PRO (&_DEP), and the insn DEP_CON (&_DEP). The first parameter is
358 the dep that represents the dependence between the two insns. The
359 second argument is the cost of the dependence as estimated by
360 the scheduler. The last argument is the distance in cycles
361 between the already scheduled insn (first parameter) and the
362 second insn (second parameter). */
363 bool (* is_costly_dependence) (struct _dep *_dep, int, int);
365 /* Given the current cost, COST, of an insn, INSN, calculate and
366 return a new cost based on its relationship to DEP_INSN through the
367 dependence of type DEP_TYPE. The default is to make no adjustment. */
368 int (* adjust_cost_2) (rtx insn, int, rtx dep_insn, int cost, int dw);
370 /* The following member value is a pointer to a function called
371 by the insn scheduler. This hook is called to notify the backend
372 that new instructions were emitted. */
373 void (* h_i_d_extended) (void);
375 /* Next 5 functions are for multi-point scheduling. */
377 /* Allocate memory for scheduler context. */
378 void *(* alloc_sched_context) (void);
380 /* Fills the context from the local machine scheduler context. */
381 void (* init_sched_context) (void *, bool);
383 /* Sets local machine scheduler context to a saved value. */
384 void (* set_sched_context) (void *);
386 /* Clears a scheduler context so it becomes like after init. */
387 void (* clear_sched_context) (void *);
389 /* Frees the scheduler context. */
390 void (* free_sched_context) (void *);
392 /* The following member value is a pointer to a function called
393 by the insn scheduler.
394 The first parameter is an instruction, the second parameter is the type
395 of the requested speculation, and the third parameter is a pointer to the
396 speculative pattern of the corresponding type (set if return value == 1).
398 -1, if there is no pattern, that will satisfy the requested speculation
400 0, if current pattern satisfies the requested speculation type,
401 1, if pattern of the instruction should be changed to the newly
403 int (* speculate_insn) (rtx, int, rtx *);
405 /* The following member value is a pointer to a function called
406 by the insn scheduler. It should return true if the check instruction
407 passed as the parameter needs a recovery block. */
408 bool (* needs_block_p) (int);
410 /* The following member value is a pointer to a function called
411 by the insn scheduler. It should return a pattern for the check
413 The first parameter is a speculative instruction, the second parameter
414 is the label of the corresponding recovery block (or null, if it is a
415 simple check). If the mutation of the check is requested (e.g. from
416 ld.c to chk.a), the third parameter is true - in this case the first
417 parameter is the previous check. */
418 rtx (* gen_spec_check) (rtx, rtx, int);
420 /* The following member value is a pointer to a function controlling
421 what insns from the ready insn queue will be considered for the
422 multipass insn scheduling. If the hook returns zero for the insn
423 passed as the parameter, the insn will not be chosen to be
424 issued. This hook is used to discard speculative instructions,
425 that stand at the first position of the ready list. */
426 bool (* first_cycle_multipass_dfa_lookahead_guard_spec) (const_rtx);
428 /* The following member value is a pointer to a function that provides
429 information about the speculation capabilities of the target.
430 The parameter is a pointer to spec_info variable. */
431 void (* set_sched_flags) (struct spec_info_def *);
433 /* Return speculation types of the instruction passed as the parameter. */
434 int (* get_insn_spec_ds) (rtx);
436 /* Return speculation types that are checked for the instruction passed as
438 int (* get_insn_checked_ds) (rtx);
440 /* Return bool if rtx scanning should just skip current layer and
441 advance to the inner rtxes. */
442 bool (* skip_rtx_p) (const_rtx);
444 /* The following member value is a pointer to a function that provides
445 information about the target resource-based lower bound which is
446 used by the swing modulo scheduler. The parameter is a pointer
448 int (* sms_res_mii) (struct ddg *);
451 /* Functions relating to vectorization. */
454 /* The following member value is a pointer to a function called
455 by the vectorizer, and return the decl of the target builtin
457 tree (* builtin_mask_for_load) (void);
459 /* Returns a code for builtin that realizes vectorized version of
460 function, or NULL_TREE if not available. */
461 tree (* builtin_vectorized_function) (unsigned, tree, tree);
463 /* Returns a code for builtin that realizes vectorized version of
464 conversion, or NULL_TREE if not available. */
465 tree (* builtin_conversion) (unsigned, tree);
467 /* Target builtin that implements vector widening multiplication.
468 builtin_mul_widen_eve computes the element-by-element products
469 for the even elements, and builtin_mul_widen_odd computes the
470 element-by-element products for the odd elements. */
471 tree (* builtin_mul_widen_even) (tree);
472 tree (* builtin_mul_widen_odd) (tree);
474 /* Returns the cost to be added to the overheads involved with
475 executing the vectorized version of a loop. */
476 int (*builtin_vectorization_cost) (bool);
478 /* Return true if vector alignment is reachable (by peeling N
479 iterations) for the given type. */
480 bool (* vector_alignment_reachable) (const_tree, bool);
482 /* Target builtin that implements vector permute. */
483 tree (* builtin_vec_perm) (tree, tree*);
486 /* The initial value of target_flags. */
487 int default_target_flags;
489 /* Handle target switch CODE (an OPT_* value). ARG is the argument
490 passed to the switch; it is NULL if no argument was. VALUE is the
491 value of ARG if CODE specifies a UInteger option, otherwise it is
492 1 if the positive form of the switch was used and 0 if the negative
493 form was. Return true if the switch was valid. */
494 bool (* handle_option) (size_t code, const char *arg, int value);
496 /* Display extra, target specific information in response to a
497 --target-help switch. */
498 void (* target_help) (void);
500 /* Return machine mode for filter value. */
501 enum machine_mode (* eh_return_filter_mode) (void);
503 /* Return machine mode for libgcc expanded cmp instructions. */
504 enum machine_mode (* libgcc_cmp_return_mode) (void);
506 /* Return machine mode for libgcc expanded shift instructions. */
507 enum machine_mode (* libgcc_shift_count_mode) (void);
509 /* Return machine mode to be used for _Unwind_Word type. */
510 enum machine_mode (* unwind_word_mode) (void);
512 /* Given two decls, merge their attributes and return the result. */
513 tree (* merge_decl_attributes) (tree, tree);
515 /* Given two types, merge their attributes and return the result. */
516 tree (* merge_type_attributes) (tree, tree);
518 /* Table of machine attributes and functions to handle them.
520 const struct attribute_spec *attribute_table;
522 /* Return zero if the attributes on TYPE1 and TYPE2 are incompatible,
523 one if they are compatible and two if they are nearly compatible
524 (which causes a warning to be generated). */
525 int (* comp_type_attributes) (const_tree type1, const_tree type2);
527 /* Assign default attributes to the newly defined TYPE. */
528 void (* set_default_type_attributes) (tree type);
530 /* Insert attributes on the newly created DECL. */
531 void (* insert_attributes) (tree decl, tree *attributes);
533 /* Return true if FNDECL (which has at least one machine attribute)
534 can be inlined despite its machine attributes, false otherwise. */
535 bool (* function_attribute_inlinable_p) (const_tree fndecl);
537 /* Return true if bitfields in RECORD_TYPE should follow the
538 Microsoft Visual C++ bitfield layout rules. */
539 bool (* ms_bitfield_layout_p) (const_tree record_type);
541 /* True if the target supports decimal floating point. */
542 bool (* decimal_float_supported_p) (void);
544 /* True if the target supports fixed-point. */
545 bool (* fixed_point_supported_p) (void);
547 /* Return true if anonymous bitfields affect structure alignment. */
548 bool (* align_anon_bitfield) (void);
550 /* Return true if volatile bitfields should use the narrowest type possible.
551 Return false if they should use the container type. */
552 bool (* narrow_volatile_bitfield) (void);
554 /* Set up target-specific built-in functions. */
555 void (* init_builtins) (void);
557 /* Expand a target-specific builtin. */
558 rtx (* expand_builtin) (tree exp, rtx target, rtx subtarget,
559 enum machine_mode mode, int ignore);
561 /* Select a replacement for a target-specific builtin. This is done
562 *before* regular type checking, and so allows the target to
563 implement a crude form of function overloading. The result is a
564 complete expression that implements the operation. PARAMS really
565 has type VEC(tree,gc)*, but we don't want to include tree.h
567 tree (*resolve_overloaded_builtin) (tree decl, void *params);
569 /* Fold a target-specific builtin. */
570 tree (* fold_builtin) (tree fndecl, tree arglist, bool ignore);
572 /* Returns a code for a target-specific builtin that implements
573 reciprocal of the function, or NULL_TREE if not available. */
574 tree (* builtin_reciprocal) (unsigned, bool, bool);
576 /* For a vendor-specific TYPE, return a pointer to a statically-allocated
577 string containing the C++ mangling for TYPE. In all other cases, return
579 const char * (* mangle_type) (const_tree type);
581 /* Make any adjustments to libfunc names needed for this target. */
582 void (* init_libfuncs) (void);
584 /* Given a decl, a section name, and whether the decl initializer
585 has relocs, choose attributes for the section. */
586 /* ??? Should be merged with SELECT_SECTION and UNIQUE_SECTION. */
587 unsigned int (* section_type_flags) (tree, const char *, int);
589 /* True if new jumps cannot be created, to replace existing ones or
590 not, at the current point in the compilation. */
591 bool (* cannot_modify_jumps_p) (void);
593 /* Return a register class for which branch target register
594 optimizations should be applied. */
595 enum reg_class (* branch_target_register_class) (void);
597 /* Return true if branch target register optimizations should include
598 callee-saved registers that are not already live during the current
599 function. AFTER_PE_GEN is true if prologues and epilogues have
600 already been generated. */
601 bool (* branch_target_register_callee_saved) (bool after_pe_gen);
603 /* True if the constant X cannot be placed in the constant pool. */
604 bool (* cannot_force_const_mem) (rtx);
606 /* True if the insn X cannot be duplicated. */
607 bool (* cannot_copy_insn_p) (rtx);
609 /* True if X is considered to be commutative. */
610 bool (* commutative_p) (const_rtx, int);
612 /* Given an invalid address X for a given machine mode, try machine-specific
613 ways to make it legitimate. Return X or an invalid address on failure. */
614 rtx (* legitimize_address) (rtx, rtx, enum machine_mode);
616 /* Given an address RTX, undo the effects of LEGITIMIZE_ADDRESS. */
617 rtx (* delegitimize_address) (rtx);
619 /* Given an address RTX, say whether it is valid. */
620 bool (* legitimate_address_p) (enum machine_mode, rtx, bool);
622 /* True if the given constant can be put into an object_block. */
623 bool (* use_blocks_for_constant_p) (enum machine_mode, const_rtx);
625 /* The minimum and maximum byte offsets for anchored addresses. */
626 HOST_WIDE_INT min_anchor_offset;
627 HOST_WIDE_INT max_anchor_offset;
629 /* True if section anchors can be used to access the given symbol. */
630 bool (* use_anchors_for_symbol_p) (const_rtx);
632 /* True if it is OK to do sibling call optimization for the specified
633 call expression EXP. DECL will be the called function, or NULL if
634 this is an indirect call. */
635 bool (*function_ok_for_sibcall) (tree decl, tree exp);
637 /* Establish appropriate back-end context for processing the function
638 FNDECL. The argument might be NULL to indicate processing at top
639 level, outside of any function scope. */
640 void (*set_current_function) (tree fndecl);
642 /* True if EXP should be placed in a "small data" section. */
643 bool (* in_small_data_p) (const_tree);
645 /* True if EXP names an object for which name resolution must resolve
646 to the current executable or shared library. */
647 bool (* binds_local_p) (const_tree);
649 /* Modify and return the identifier of a DECL's external name,
650 originally identified by ID, as required by the target,
651 (eg, append @nn to windows32 stdcall function names).
652 The default is to return ID without modification. */
653 tree (* mangle_decl_assembler_name) (tree decl, tree id);
655 /* Do something target-specific to record properties of the DECL into
656 the associated SYMBOL_REF. */
657 void (* encode_section_info) (tree, rtx, int);
659 /* Undo the effects of encode_section_info on the symbol string. */
660 const char * (* strip_name_encoding) (const char *);
662 /* If shift optabs for MODE are known to always truncate the shift count,
663 return the mask that they apply. Return 0 otherwise. */
664 unsigned HOST_WIDE_INT (* shift_truncation_mask) (enum machine_mode mode);
666 /* Return the number of divisions in the given MODE that should be present,
667 so that it is profitable to turn the division into a multiplication by
669 unsigned int (* min_divisions_for_recip_mul) (enum machine_mode mode);
671 /* If the representation of integral MODE is such that values are
672 always sign-extended to a wider mode MODE_REP then return
673 SIGN_EXTEND. Return UNKNOWN otherwise. */
674 /* Note that the return type ought to be RTX_CODE, but that's not
675 necessarily defined at this point. */
676 int (* mode_rep_extended) (enum machine_mode mode,
677 enum machine_mode mode_rep);
679 /* True if MODE is valid for a pointer in __attribute__((mode("MODE"))). */
680 bool (* valid_pointer_mode) (enum machine_mode mode);
682 /* True if MODE is valid for the target. By "valid", we mean able to
683 be manipulated in non-trivial ways. In particular, this means all
684 the arithmetic is supported. */
685 bool (* scalar_mode_supported_p) (enum machine_mode mode);
687 /* Similarly for vector modes. "Supported" here is less strict. At
688 least some operations are supported; need to check optabs or builtins
689 for further details. */
690 bool (* vector_mode_supported_p) (enum machine_mode mode);
692 /* Compute a (partial) cost for rtx X. Return true if the complete
693 cost has been computed, and false if subexpressions should be
694 scanned. In either case, *TOTAL contains the cost result. */
695 /* Note that CODE and OUTER_CODE ought to be RTX_CODE, but that's
696 not necessarily defined at this point. */
697 bool (* rtx_costs) (rtx x, int code, int outer_code, int *total, bool speed);
699 /* Compute the cost of X, used as an address. Never called with
700 invalid addresses. */
701 int (* address_cost) (rtx x, bool speed);
703 /* Return where to allocate pseudo for a given hard register initial
705 rtx (* allocate_initial_value) (rtx x);
707 /* Return nonzero if evaluating UNSPEC[_VOLATILE] X might cause a trap.
708 FLAGS has the same meaning as in rtlanal.c: may_trap_p_1. */
709 int (* unspec_may_trap_p) (const_rtx x, unsigned flags);
711 /* Given a register, this hook should return a parallel of registers
712 to represent where to find the register pieces. Define this hook
713 if the register and its mode are represented in Dwarf in
714 non-contiguous locations, or if the register should be
715 represented in more than one register in Dwarf. Otherwise, this
716 hook should return NULL_RTX. */
717 rtx (* dwarf_register_span) (rtx);
719 /* If expand_builtin_init_dwarf_reg_sizes needs to fill in table
720 entries not corresponding directly to registers below
721 FIRST_PSEUDO_REGISTER, this hook should generate the necessary
722 code, given the address of the table. */
723 void (* init_dwarf_reg_sizes_extra) (tree);
725 /* Fetch the fixed register(s) which hold condition codes, for
726 targets where it makes sense to look for duplicate assignments to
727 the condition codes. This should return true if there is such a
728 register, false otherwise. The arguments should be set to the
729 fixed register numbers. Up to two condition code registers are
730 supported. If there is only one for this target, the int pointed
731 at by the second argument should be set to -1. */
732 bool (* fixed_condition_code_regs) (unsigned int *, unsigned int *);
734 /* If two condition code modes are compatible, return a condition
735 code mode which is compatible with both, such that a comparison
736 done in the returned mode will work for both of the original
737 modes. If the condition code modes are not compatible, return
739 enum machine_mode (* cc_modes_compatible) (enum machine_mode,
742 /* Do machine-dependent code transformations. Called just before
743 delayed-branch scheduling. */
744 void (* machine_dependent_reorg) (void);
746 /* Create the __builtin_va_list type. */
747 tree (* build_builtin_va_list) (void);
749 /* Get the cfun/fndecl calling abi __builtin_va_list type. */
750 tree (* fn_abi_va_list) (tree);
752 /* Get the __builtin_va_list type dependent on input type. */
753 tree (* canonical_va_list_type) (tree);
755 /* Expand the __builtin_va_start builtin. */
756 void (* expand_builtin_va_start) (tree valist, rtx nextarg);
758 /* Gimplifies a VA_ARG_EXPR. */
759 tree (* gimplify_va_arg_expr) (tree valist, tree type, gimple_seq *pre_p,
762 /* Validity-checking routines for PCH files, target-specific.
763 get_pch_validity returns a pointer to the data to be stored,
764 and stores the size in its argument. pch_valid_p gets the same
765 information back and returns NULL if the PCH is valid,
766 or an error message if not.
768 void * (* get_pch_validity) (size_t *);
769 const char * (* pch_valid_p) (const void *, size_t);
771 /* If nonnull, this function checks whether a PCH file with the
772 given set of target flags can be used. It returns NULL if so,
773 otherwise it returns an error message. */
774 const char *(*check_pch_target_flags) (int);
776 /* True if the compiler should give an enum type only as many
777 bytes as it takes to represent the range of possible values of
779 bool (* default_short_enums) (void);
781 /* This target hook returns an rtx that is used to store the address
782 of the current frame into the built-in setjmp buffer. */
783 rtx (* builtin_setjmp_frame_value) (void);
785 /* This target hook should add STRING_CST trees for any hard regs
786 the port wishes to automatically clobber for an asm. */
787 tree (* md_asm_clobbers) (tree, tree, tree);
789 /* This target hook allows the backend to specify a calling convention
790 in the debug information. This function actually returns an
791 enum dwarf_calling_convention, but because of forward declarations
792 and not wanting to include dwarf2.h everywhere target.h is included
793 the function is being declared as an int. */
794 int (* dwarf_calling_convention) (const_tree);
796 /* This target hook allows the backend to emit frame-related insns that
797 contain UNSPECs or UNSPEC_VOLATILEs. The call frame debugging info
798 engine will invoke it on insns of the form
799 (set (reg) (unspec [...] UNSPEC_INDEX))
801 (set (reg) (unspec_volatile [...] UNSPECV_INDEX))
802 to let the backend emit the call frame instructions. */
803 void (* dwarf_handle_frame_unspec) (const char *, rtx, int);
805 /* Perform architecture specific checking of statements gimplified
806 from VA_ARG_EXPR. STMT is the statement. Returns true if the statement
807 doesn't need to be checked for va_list references. */
808 bool (* stdarg_optimize_hook) (struct stdarg_info *ai, const_gimple stmt);
810 /* This target hook allows the operating system to override the DECL
811 that represents the external variable that contains the stack
812 protection guard variable. The type of this DECL is ptr_type_node. */
813 tree (* stack_protect_guard) (void);
815 /* This target hook allows the operating system to override the CALL_EXPR
816 that is invoked when a check vs the guard variable fails. */
817 tree (* stack_protect_fail) (void);
819 /* Returns NULL if target supports the insn within a doloop block,
820 otherwise it returns an error message. */
821 const char * (*invalid_within_doloop) (const_rtx);
823 /* DECL is a variable or function with __attribute__((dllimport))
824 specified. Use this hook if the target needs to add extra validation
825 checks to handle_dll_attribute (). */
826 bool (* valid_dllimport_attribute_p) (const_tree decl);
828 /* If non-zero, align constant anchors in CSE to a multiple of this
830 unsigned HOST_WIDE_INT const_anchor;
832 /* Functions relating to calls - argument passing, returns, etc. */
834 bool (*promote_function_args) (const_tree fntype);
835 bool (*promote_function_return) (const_tree fntype);
836 bool (*promote_prototypes) (const_tree fntype);
837 rtx (*struct_value_rtx) (tree fndecl, int incoming);
838 bool (*return_in_memory) (const_tree type, const_tree fndecl);
839 bool (*return_in_msb) (const_tree type);
841 /* Return true if a parameter must be passed by reference. TYPE may
842 be null if this is a libcall. CA may be null if this query is
843 from __builtin_va_arg. */
844 bool (*pass_by_reference) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
845 const_tree type, bool named_arg);
847 rtx (*expand_builtin_saveregs) (void);
848 /* Returns pretend_argument_size. */
849 void (*setup_incoming_varargs) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
850 tree type, int *pretend_arg_size,
852 bool (*strict_argument_naming) (CUMULATIVE_ARGS *ca);
853 /* Returns true if we should use
854 targetm.calls.setup_incoming_varargs() and/or
855 targetm.calls.strict_argument_naming(). */
856 bool (*pretend_outgoing_varargs_named) (CUMULATIVE_ARGS *ca);
858 /* Given a complex type T, return true if a parameter of type T
859 should be passed as two scalars. */
860 bool (* split_complex_arg) (const_tree type);
862 /* Return true if type T, mode MODE, may not be passed in registers,
863 but must be passed on the stack. */
864 /* ??? This predicate should be applied strictly after pass-by-reference.
865 Need audit to verify that this is the case. */
866 bool (* must_pass_in_stack) (enum machine_mode mode, const_tree t);
868 /* Return true if type TYPE, mode MODE, which is passed by reference,
869 should have the object copy generated by the callee rather than
870 the caller. It is never called for TYPE requiring constructors. */
871 bool (* callee_copies) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
872 const_tree type, bool named);
874 /* Return zero for arguments passed entirely on the stack or entirely
875 in registers. If passed in both, return the number of bytes passed
876 in registers; the balance is therefore passed on the stack. */
877 int (* arg_partial_bytes) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
878 tree type, bool named);
880 /* Return the diagnostic message string if function without a prototype
881 is not allowed for this 'val' argument; NULL otherwise. */
882 const char *(*invalid_arg_for_unprototyped_fn) (const_tree typelist,
886 /* Return an rtx for the return value location of the function
887 specified by FN_DECL_OR_TYPE with a return type of RET_TYPE. */
888 rtx (*function_value) (const_tree ret_type, const_tree fn_decl_or_type,
891 /* Return an rtx for the argument pointer incoming to the
893 rtx (*internal_arg_pointer) (void);
895 /* Update the current function stack boundary if needed. */
896 void (*update_stack_boundary) (void);
898 /* Handle stack alignment and return an rtx for Dynamic Realign
899 Argument Pointer if necessary. */
900 rtx (*get_drap_rtx) (void);
902 /* Return true if all function parameters should be spilled to the
904 bool (*allocate_stack_slots_for_args) (void);
908 /* Return the diagnostic message string if conversion from FROMTYPE
909 to TOTYPE is not allowed, NULL otherwise. */
910 const char *(*invalid_conversion) (const_tree fromtype, const_tree totype);
912 /* Return the diagnostic message string if the unary operation OP is
913 not permitted on TYPE, NULL otherwise. */
914 const char *(*invalid_unary_op) (int op, const_tree type);
916 /* Return the diagnostic message string if the binary operation OP
917 is not permitted on TYPE1 and TYPE2, NULL otherwise. */
918 const char *(*invalid_binary_op) (int op, const_tree type1, const_tree type2);
920 /* Return the diagnostic message string if TYPE is not valid as a
921 function parameter type, NULL otherwise. */
922 const char *(*invalid_parameter_type) (const_tree type);
924 /* Return the diagnostic message string if TYPE is not valid as a
925 function return type, NULL otherwise. */
926 const char *(*invalid_return_type) (const_tree type);
928 /* If values of TYPE are promoted to some other type when used in
929 expressions (analogous to the integer promotions), return that type,
930 or NULL_TREE otherwise. */
931 tree (*promoted_type) (const_tree type);
933 /* Convert EXPR to TYPE, if target-specific types with special conversion
934 rules are involved. Return the converted expression, or NULL to apply
935 the standard conversion rules. */
936 tree (*convert_to_type) (tree type, tree expr);
938 /* Return the array of IRA cover classes for the current target. */
939 const enum reg_class *(*ira_cover_classes) (void);
941 /* Return the class for a secondary reload, and fill in extra information. */
942 enum reg_class (*secondary_reload) (bool, rtx, enum reg_class,
944 struct secondary_reload_info *);
946 /* This target hook allows the backend to perform additional
947 processing while initializing for variable expansion. */
948 void (* expand_to_rtl_hook) (void);
950 /* This target hook allows the backend to perform additional
951 instantiations on rtx that are not actually in insns yet,
952 but will be later. */
953 void (* instantiate_decls) (void);
955 /* Return true if is OK to use a hard register REGNO as scratch register
957 bool (* hard_regno_scratch_ok) (unsigned int regno);
959 /* Return the smallest number of different values for which it is best to
960 use a jump-table instead of a tree of conditional branches. */
961 unsigned int (* case_values_threshold) (void);
963 /* Functions specific to the C family of frontends. */
965 /* Return machine mode for non-standard suffix
966 or VOIDmode if non-standard suffixes are unsupported. */
967 enum machine_mode (*mode_for_suffix) (char);
970 /* Functions specific to the C++ frontend. */
972 /* Return the integer type used for guard variables. */
973 tree (*guard_type) (void);
974 /* Return true if only the low bit of the guard should be tested. */
975 bool (*guard_mask_bit) (void);
976 /* Returns the size of the array cookie for an array of type. */
977 tree (*get_cookie_size) (tree);
978 /* Returns true if the element size should be stored in the
980 bool (*cookie_has_size) (void);
981 /* Allows backends to perform additional processing when
982 deciding if a class should be exported or imported. */
983 int (*import_export_class) (tree, int);
984 /* Returns true if constructors and destructors return "this". */
985 bool (*cdtor_returns_this) (void);
986 /* Returns true if the key method for a class can be an inline
987 function, so long as it is not declared inline in the class
988 itself. Returning true is the behavior required by the Itanium
990 bool (*key_method_may_be_inline) (void);
991 /* DECL is a virtual table, virtual table table, typeinfo object,
992 or other similar implicit class data object that will be
993 emitted with external linkage in this translation unit. No ELF
994 visibility has been explicitly specified. If the target needs
995 to specify a visibility other than that of the containing class,
996 use this hook to set DECL_VISIBILITY and
997 DECL_VISIBILITY_SPECIFIED. */
998 void (*determine_class_data_visibility) (tree decl);
999 /* Returns true (the default) if virtual tables and other
1000 similar implicit class data objects are always COMDAT if they
1001 have external linkage. If this hook returns false, then
1002 class data for classes whose virtual table will be emitted in
1003 only one translation unit will not be COMDAT. */
1004 bool (*class_data_always_comdat) (void);
1005 /* Returns true (the default) if the RTTI for the basic types,
1006 which is always defined in the C++ runtime, should be COMDAT;
1007 false if it should not be COMDAT. */
1008 bool (*library_rtti_comdat) (void);
1009 /* Returns true if __aeabi_atexit should be used to register static
1011 bool (*use_aeabi_atexit) (void);
1012 /* Returns true if target may use atexit in the same manner as
1013 __cxa_atexit to register static destructors. */
1014 bool (*use_atexit_for_cxa_atexit) (void);
1015 /* TYPE is a C++ class (i.e., RECORD_TYPE or UNION_TYPE) that
1016 has just been defined. Use this hook to make adjustments to the
1017 class (eg, tweak visibility or perform any other required
1018 target modifications). */
1019 void (*adjust_class_at_definition) (tree type);
1022 /* Functions and data for emulated TLS support. */
1024 /* Name of the address and common functions. */
1025 const char *get_address;
1026 const char *register_common;
1028 /* Prefixes for proxy variable and template. */
1029 const char *var_section;
1030 const char *tmpl_section;
1032 /* Prefixes for proxy variable and template. */
1033 const char *var_prefix;
1034 const char *tmpl_prefix;
1036 /* Function to generate field definitions of the proxy variable. */
1037 tree (*var_fields) (tree, tree *);
1039 /* Function to initialize a proxy variable. */
1040 tree (*var_init) (tree, tree, tree);
1042 /* Whether we are allowed to alter the usual alignment of the
1044 bool var_align_fixed;
1046 /* Whether we can emit debug information for TLS vars. */
1047 bool debug_form_tls_address;
1050 struct target_option_hooks {
1051 /* Function to validate the attribute((option(...))) strings or NULL. If
1052 the option is validated, it is assumed that DECL_FUNCTION_SPECIFIC will
1053 be filled in in the function decl node. */
1054 bool (*valid_attribute_p) (tree, tree, tree, int);
1056 /* Function to save any extra target state in the target options
1058 void (*save) (struct cl_target_option *);
1060 /* Function to restore any extra target state from the target options
1062 void (*restore) (struct cl_target_option *);
1064 /* Function to print any extra target state from the target options
1066 void (*print) (FILE *, int, struct cl_target_option *);
1068 /* Function to parse arguments to be validated for #pragma option, and to
1069 change the state if the options are valid. If the first argument is
1070 NULL, the second argument specifies the default options to use. Return
1071 true if the options are valid, and set the current state. */
1072 bool (*pragma_parse) (tree, tree);
1074 /* Function to determine if one function can inline another function. */
1075 bool (*can_inline_p) (tree, tree);
1078 /* For targets that need to mark extra registers as live on entry to
1079 the function, they should define this target hook and set their
1080 bits in the bitmap passed in. */
1081 void (*live_on_entry) (bitmap);
1083 /* True if unwinding tables should be generated by default. */
1084 bool unwind_tables_default;
1086 /* Leave the boolean fields at the end. */
1088 /* True if arbitrary sections are supported. */
1089 bool have_named_sections;
1091 /* True if we can create zeroed data by switching to a BSS section
1092 and then using ASM_OUTPUT_SKIP to allocate the space. */
1093 bool have_switchable_bss_sections;
1095 /* True if "native" constructors and destructors are supported,
1096 false if we're using collect2 for the job. */
1097 bool have_ctors_dtors;
1099 /* True if thread-local storage is supported. */
1102 /* True if a small readonly data section is supported. */
1103 bool have_srodata_section;
1105 /* True if EH frame info sections should be zero-terminated. */
1106 bool terminate_dw2_eh_frame_info;
1108 /* True if #NO_APP should be emitted at the beginning of
1110 bool file_start_app_off;
1112 /* True if output_file_directive should be called for main_input_filename
1113 at the beginning of assembly output. */
1114 bool file_start_file_directive;
1116 /* True if #pragma redefine_extname is to be supported. */
1117 bool handle_pragma_redefine_extname;
1119 /* True if #pragma extern_prefix is to be supported. */
1120 bool handle_pragma_extern_prefix;
1122 /* True if the target is allowed to reorder memory accesses unless
1123 synchronization is explicitly requested. */
1124 bool relaxed_ordering;
1126 /* Returns true if we should generate exception tables for use with the
1127 ARM EABI. The effects the encoding of function exception specifications.
1129 bool arm_eabi_unwinder;
1131 /* Leave the boolean fields at the end. */
1134 extern struct gcc_target targetm;
1136 struct gcc_targetcm {
1137 /* Handle target switch CODE (an OPT_* value). ARG is the argument
1138 passed to the switch; it is NULL if no argument was. VALUE is the
1139 value of ARG if CODE specifies a UInteger option, otherwise it is
1140 1 if the positive form of the switch was used and 0 if the negative
1141 form was. Return true if the switch was valid. */
1142 bool (*handle_c_option) (size_t code, const char *arg, int value);
1145 /* Each target can provide their own. */
1146 extern struct gcc_targetcm targetcm;
1148 #endif /* GCC_TARGET_H */
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