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*);
484 /* Return true if the target supports misaligned store/load of a
485 specific factor denoted in the third parameter. The last parameter
486 is true if the access is defined in a packed struct. */
487 bool (* builtin_support_vector_misalignment) (enum machine_mode,
488 const_tree, int, bool);
491 /* The initial value of target_flags. */
492 int default_target_flags;
494 /* Handle target switch CODE (an OPT_* value). ARG is the argument
495 passed to the switch; it is NULL if no argument was. VALUE is the
496 value of ARG if CODE specifies a UInteger option, otherwise it is
497 1 if the positive form of the switch was used and 0 if the negative
498 form was. Return true if the switch was valid. */
499 bool (* handle_option) (size_t code, const char *arg, int value);
501 /* Display extra, target specific information in response to a
502 --target-help switch. */
503 void (* target_help) (void);
505 /* Return machine mode for filter value. */
506 enum machine_mode (* eh_return_filter_mode) (void);
508 /* Return machine mode for libgcc expanded cmp instructions. */
509 enum machine_mode (* libgcc_cmp_return_mode) (void);
511 /* Return machine mode for libgcc expanded shift instructions. */
512 enum machine_mode (* libgcc_shift_count_mode) (void);
514 /* Return machine mode to be used for _Unwind_Word type. */
515 enum machine_mode (* unwind_word_mode) (void);
517 /* Given two decls, merge their attributes and return the result. */
518 tree (* merge_decl_attributes) (tree, tree);
520 /* Given two types, merge their attributes and return the result. */
521 tree (* merge_type_attributes) (tree, tree);
523 /* Table of machine attributes and functions to handle them.
525 const struct attribute_spec *attribute_table;
527 /* Return zero if the attributes on TYPE1 and TYPE2 are incompatible,
528 one if they are compatible and two if they are nearly compatible
529 (which causes a warning to be generated). */
530 int (* comp_type_attributes) (const_tree type1, const_tree type2);
532 /* Assign default attributes to the newly defined TYPE. */
533 void (* set_default_type_attributes) (tree type);
535 /* Insert attributes on the newly created DECL. */
536 void (* insert_attributes) (tree decl, tree *attributes);
538 /* Return true if FNDECL (which has at least one machine attribute)
539 can be inlined despite its machine attributes, false otherwise. */
540 bool (* function_attribute_inlinable_p) (const_tree fndecl);
542 /* Return true if bitfields in RECORD_TYPE should follow the
543 Microsoft Visual C++ bitfield layout rules. */
544 bool (* ms_bitfield_layout_p) (const_tree record_type);
546 /* True if the target supports decimal floating point. */
547 bool (* decimal_float_supported_p) (void);
549 /* True if the target supports fixed-point. */
550 bool (* fixed_point_supported_p) (void);
552 /* Return true if anonymous bitfields affect structure alignment. */
553 bool (* align_anon_bitfield) (void);
555 /* Return true if volatile bitfields should use the narrowest type possible.
556 Return false if they should use the container type. */
557 bool (* narrow_volatile_bitfield) (void);
559 /* Set up target-specific built-in functions. */
560 void (* init_builtins) (void);
562 /* Expand a target-specific builtin. */
563 rtx (* expand_builtin) (tree exp, rtx target, rtx subtarget,
564 enum machine_mode mode, int ignore);
566 /* Select a replacement for a target-specific builtin. This is done
567 *before* regular type checking, and so allows the target to
568 implement a crude form of function overloading. The result is a
569 complete expression that implements the operation. PARAMS really
570 has type VEC(tree,gc)*, but we don't want to include tree.h
572 tree (*resolve_overloaded_builtin) (unsigned int /*location_t*/,
573 tree decl, void *params);
575 /* Fold a target-specific builtin. */
576 tree (* fold_builtin) (tree fndecl, tree arglist, bool ignore);
578 /* Returns a code for a target-specific builtin that implements
579 reciprocal of the function, or NULL_TREE if not available. */
580 tree (* builtin_reciprocal) (unsigned, bool, bool);
582 /* For a vendor-specific TYPE, return a pointer to a statically-allocated
583 string containing the C++ mangling for TYPE. In all other cases, return
585 const char * (* mangle_type) (const_tree type);
587 /* Make any adjustments to libfunc names needed for this target. */
588 void (* init_libfuncs) (void);
590 /* Given a decl, a section name, and whether the decl initializer
591 has relocs, choose attributes for the section. */
592 /* ??? Should be merged with SELECT_SECTION and UNIQUE_SECTION. */
593 unsigned int (* section_type_flags) (tree, const char *, int);
595 /* True if new jumps cannot be created, to replace existing ones or
596 not, at the current point in the compilation. */
597 bool (* cannot_modify_jumps_p) (void);
599 /* Return a register class for which branch target register
600 optimizations should be applied. */
601 enum reg_class (* branch_target_register_class) (void);
603 /* Return true if branch target register optimizations should include
604 callee-saved registers that are not already live during the current
605 function. AFTER_PE_GEN is true if prologues and epilogues have
606 already been generated. */
607 bool (* branch_target_register_callee_saved) (bool after_pe_gen);
609 /* True if the constant X cannot be placed in the constant pool. */
610 bool (* cannot_force_const_mem) (rtx);
612 /* True if the insn X cannot be duplicated. */
613 bool (* cannot_copy_insn_p) (rtx);
615 /* True if X is considered to be commutative. */
616 bool (* commutative_p) (const_rtx, int);
618 /* Given an invalid address X for a given machine mode, try machine-specific
619 ways to make it legitimate. Return X or an invalid address on failure. */
620 rtx (* legitimize_address) (rtx, rtx, enum machine_mode);
622 /* Given an address RTX, undo the effects of LEGITIMIZE_ADDRESS. */
623 rtx (* delegitimize_address) (rtx);
625 /* Given an address RTX, say whether it is valid. */
626 bool (* legitimate_address_p) (enum machine_mode, rtx, bool);
628 /* True if the given constant can be put into an object_block. */
629 bool (* use_blocks_for_constant_p) (enum machine_mode, const_rtx);
631 /* The minimum and maximum byte offsets for anchored addresses. */
632 HOST_WIDE_INT min_anchor_offset;
633 HOST_WIDE_INT max_anchor_offset;
635 /* True if section anchors can be used to access the given symbol. */
636 bool (* use_anchors_for_symbol_p) (const_rtx);
638 /* True if it is OK to do sibling call optimization for the specified
639 call expression EXP. DECL will be the called function, or NULL if
640 this is an indirect call. */
641 bool (*function_ok_for_sibcall) (tree decl, tree exp);
643 /* Establish appropriate back-end context for processing the function
644 FNDECL. The argument might be NULL to indicate processing at top
645 level, outside of any function scope. */
646 void (*set_current_function) (tree fndecl);
648 /* True if EXP should be placed in a "small data" section. */
649 bool (* in_small_data_p) (const_tree);
651 /* True if EXP names an object for which name resolution must resolve
652 to the current executable or shared library. */
653 bool (* binds_local_p) (const_tree);
655 /* Modify and return the identifier of a DECL's external name,
656 originally identified by ID, as required by the target,
657 (eg, append @nn to windows32 stdcall function names).
658 The default is to return ID without modification. */
659 tree (* mangle_decl_assembler_name) (tree decl, tree id);
661 /* Do something target-specific to record properties of the DECL into
662 the associated SYMBOL_REF. */
663 void (* encode_section_info) (tree, rtx, int);
665 /* Undo the effects of encode_section_info on the symbol string. */
666 const char * (* strip_name_encoding) (const char *);
668 /* If shift optabs for MODE are known to always truncate the shift count,
669 return the mask that they apply. Return 0 otherwise. */
670 unsigned HOST_WIDE_INT (* shift_truncation_mask) (enum machine_mode mode);
672 /* Return the number of divisions in the given MODE that should be present,
673 so that it is profitable to turn the division into a multiplication by
675 unsigned int (* min_divisions_for_recip_mul) (enum machine_mode mode);
677 /* If the representation of integral MODE is such that values are
678 always sign-extended to a wider mode MODE_REP then return
679 SIGN_EXTEND. Return UNKNOWN otherwise. */
680 /* Note that the return type ought to be RTX_CODE, but that's not
681 necessarily defined at this point. */
682 int (* mode_rep_extended) (enum machine_mode mode,
683 enum machine_mode mode_rep);
685 /* True if MODE is valid for a pointer in __attribute__((mode("MODE"))). */
686 bool (* valid_pointer_mode) (enum machine_mode mode);
688 /* True if MODE is valid for the target. By "valid", we mean able to
689 be manipulated in non-trivial ways. In particular, this means all
690 the arithmetic is supported. */
691 bool (* scalar_mode_supported_p) (enum machine_mode mode);
693 /* Similarly for vector modes. "Supported" here is less strict. At
694 least some operations are supported; need to check optabs or builtins
695 for further details. */
696 bool (* vector_mode_supported_p) (enum machine_mode mode);
698 /* Compute a (partial) cost for rtx X. Return true if the complete
699 cost has been computed, and false if subexpressions should be
700 scanned. In either case, *TOTAL contains the cost result. */
701 /* Note that CODE and OUTER_CODE ought to be RTX_CODE, but that's
702 not necessarily defined at this point. */
703 bool (* rtx_costs) (rtx x, int code, int outer_code, int *total, bool speed);
705 /* Compute the cost of X, used as an address. Never called with
706 invalid addresses. */
707 int (* address_cost) (rtx x, bool speed);
709 /* Return where to allocate pseudo for a given hard register initial
711 rtx (* allocate_initial_value) (rtx x);
713 /* Return nonzero if evaluating UNSPEC[_VOLATILE] X might cause a trap.
714 FLAGS has the same meaning as in rtlanal.c: may_trap_p_1. */
715 int (* unspec_may_trap_p) (const_rtx x, unsigned flags);
717 /* Given a register, this hook should return a parallel of registers
718 to represent where to find the register pieces. Define this hook
719 if the register and its mode are represented in Dwarf in
720 non-contiguous locations, or if the register should be
721 represented in more than one register in Dwarf. Otherwise, this
722 hook should return NULL_RTX. */
723 rtx (* dwarf_register_span) (rtx);
725 /* If expand_builtin_init_dwarf_reg_sizes needs to fill in table
726 entries not corresponding directly to registers below
727 FIRST_PSEUDO_REGISTER, this hook should generate the necessary
728 code, given the address of the table. */
729 void (* init_dwarf_reg_sizes_extra) (tree);
731 /* Fetch the fixed register(s) which hold condition codes, for
732 targets where it makes sense to look for duplicate assignments to
733 the condition codes. This should return true if there is such a
734 register, false otherwise. The arguments should be set to the
735 fixed register numbers. Up to two condition code registers are
736 supported. If there is only one for this target, the int pointed
737 at by the second argument should be set to -1. */
738 bool (* fixed_condition_code_regs) (unsigned int *, unsigned int *);
740 /* If two condition code modes are compatible, return a condition
741 code mode which is compatible with both, such that a comparison
742 done in the returned mode will work for both of the original
743 modes. If the condition code modes are not compatible, return
745 enum machine_mode (* cc_modes_compatible) (enum machine_mode,
748 /* Do machine-dependent code transformations. Called just before
749 delayed-branch scheduling. */
750 void (* machine_dependent_reorg) (void);
752 /* Create the __builtin_va_list type. */
753 tree (* build_builtin_va_list) (void);
755 /* Get the cfun/fndecl calling abi __builtin_va_list type. */
756 tree (* fn_abi_va_list) (tree);
758 /* Get the __builtin_va_list type dependent on input type. */
759 tree (* canonical_va_list_type) (tree);
761 /* Expand the __builtin_va_start builtin. */
762 void (* expand_builtin_va_start) (tree valist, rtx nextarg);
764 /* Gimplifies a VA_ARG_EXPR. */
765 tree (* gimplify_va_arg_expr) (tree valist, tree type, gimple_seq *pre_p,
768 /* Validity-checking routines for PCH files, target-specific.
769 get_pch_validity returns a pointer to the data to be stored,
770 and stores the size in its argument. pch_valid_p gets the same
771 information back and returns NULL if the PCH is valid,
772 or an error message if not.
774 void * (* get_pch_validity) (size_t *);
775 const char * (* pch_valid_p) (const void *, size_t);
777 /* If nonnull, this function checks whether a PCH file with the
778 given set of target flags can be used. It returns NULL if so,
779 otherwise it returns an error message. */
780 const char *(*check_pch_target_flags) (int);
782 /* True if the compiler should give an enum type only as many
783 bytes as it takes to represent the range of possible values of
785 bool (* default_short_enums) (void);
787 /* This target hook returns an rtx that is used to store the address
788 of the current frame into the built-in setjmp buffer. */
789 rtx (* builtin_setjmp_frame_value) (void);
791 /* This target hook should add STRING_CST trees for any hard regs
792 the port wishes to automatically clobber for an asm. */
793 tree (* md_asm_clobbers) (tree, tree, tree);
795 /* This target hook allows the backend to specify a calling convention
796 in the debug information. This function actually returns an
797 enum dwarf_calling_convention, but because of forward declarations
798 and not wanting to include dwarf2.h everywhere target.h is included
799 the function is being declared as an int. */
800 int (* dwarf_calling_convention) (const_tree);
802 /* This target hook allows the backend to emit frame-related insns that
803 contain UNSPECs or UNSPEC_VOLATILEs. The call frame debugging info
804 engine will invoke it on insns of the form
805 (set (reg) (unspec [...] UNSPEC_INDEX))
807 (set (reg) (unspec_volatile [...] UNSPECV_INDEX))
808 to let the backend emit the call frame instructions. */
809 void (* dwarf_handle_frame_unspec) (const char *, rtx, int);
811 /* Perform architecture specific checking of statements gimplified
812 from VA_ARG_EXPR. STMT is the statement. Returns true if the statement
813 doesn't need to be checked for va_list references. */
814 bool (* stdarg_optimize_hook) (struct stdarg_info *ai, const_gimple stmt);
816 /* This target hook allows the operating system to override the DECL
817 that represents the external variable that contains the stack
818 protection guard variable. The type of this DECL is ptr_type_node. */
819 tree (* stack_protect_guard) (void);
821 /* This target hook allows the operating system to override the CALL_EXPR
822 that is invoked when a check vs the guard variable fails. */
823 tree (* stack_protect_fail) (void);
825 /* Returns NULL if target supports the insn within a doloop block,
826 otherwise it returns an error message. */
827 const char * (*invalid_within_doloop) (const_rtx);
829 /* DECL is a variable or function with __attribute__((dllimport))
830 specified. Use this hook if the target needs to add extra validation
831 checks to handle_dll_attribute (). */
832 bool (* valid_dllimport_attribute_p) (const_tree decl);
834 /* If non-zero, align constant anchors in CSE to a multiple of this
836 unsigned HOST_WIDE_INT const_anchor;
838 /* Functions relating to calls - argument passing, returns, etc. */
840 enum machine_mode (*promote_function_mode) (const_tree type,
841 enum machine_mode mode,
845 bool (*promote_prototypes) (const_tree fntype);
846 rtx (*struct_value_rtx) (tree fndecl, int incoming);
847 bool (*return_in_memory) (const_tree type, const_tree fndecl);
848 bool (*return_in_msb) (const_tree type);
850 /* Return true if a parameter must be passed by reference. TYPE may
851 be null if this is a libcall. CA may be null if this query is
852 from __builtin_va_arg. */
853 bool (*pass_by_reference) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
854 const_tree type, bool named_arg);
856 rtx (*expand_builtin_saveregs) (void);
857 /* Returns pretend_argument_size. */
858 void (*setup_incoming_varargs) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
859 tree type, int *pretend_arg_size,
861 bool (*strict_argument_naming) (CUMULATIVE_ARGS *ca);
862 /* Returns true if we should use
863 targetm.calls.setup_incoming_varargs() and/or
864 targetm.calls.strict_argument_naming(). */
865 bool (*pretend_outgoing_varargs_named) (CUMULATIVE_ARGS *ca);
867 /* Given a complex type T, return true if a parameter of type T
868 should be passed as two scalars. */
869 bool (* split_complex_arg) (const_tree type);
871 /* Return true if type T, mode MODE, may not be passed in registers,
872 but must be passed on the stack. */
873 /* ??? This predicate should be applied strictly after pass-by-reference.
874 Need audit to verify that this is the case. */
875 bool (* must_pass_in_stack) (enum machine_mode mode, const_tree t);
877 /* Return true if type TYPE, mode MODE, which is passed by reference,
878 should have the object copy generated by the callee rather than
879 the caller. It is never called for TYPE requiring constructors. */
880 bool (* callee_copies) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
881 const_tree type, bool named);
883 /* Return zero for arguments passed entirely on the stack or entirely
884 in registers. If passed in both, return the number of bytes passed
885 in registers; the balance is therefore passed on the stack. */
886 int (* arg_partial_bytes) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
887 tree type, bool named);
889 /* Return the diagnostic message string if function without a prototype
890 is not allowed for this 'val' argument; NULL otherwise. */
891 const char *(*invalid_arg_for_unprototyped_fn) (const_tree typelist,
895 /* Return an rtx for the return value location of the function
896 specified by FN_DECL_OR_TYPE with a return type of RET_TYPE. */
897 rtx (*function_value) (const_tree ret_type, const_tree fn_decl_or_type,
900 /* Return the rtx for the result of a libcall of mode MODE,
901 calling the function FN_NAME. */
902 rtx (*libcall_value) (enum machine_mode, rtx);
904 /* Return an rtx for the argument pointer incoming to the
906 rtx (*internal_arg_pointer) (void);
908 /* Update the current function stack boundary if needed. */
909 void (*update_stack_boundary) (void);
911 /* Handle stack alignment and return an rtx for Dynamic Realign
912 Argument Pointer if necessary. */
913 rtx (*get_drap_rtx) (void);
915 /* Return true if all function parameters should be spilled to the
917 bool (*allocate_stack_slots_for_args) (void);
921 /* Return the diagnostic message string if conversion from FROMTYPE
922 to TOTYPE is not allowed, NULL otherwise. */
923 const char *(*invalid_conversion) (const_tree fromtype, const_tree totype);
925 /* Return the diagnostic message string if the unary operation OP is
926 not permitted on TYPE, NULL otherwise. */
927 const char *(*invalid_unary_op) (int op, const_tree type);
929 /* Return the diagnostic message string if the binary operation OP
930 is not permitted on TYPE1 and TYPE2, NULL otherwise. */
931 const char *(*invalid_binary_op) (int op, const_tree type1, const_tree type2);
933 /* Return the diagnostic message string if TYPE is not valid as a
934 function parameter type, NULL otherwise. */
935 const char *(*invalid_parameter_type) (const_tree type);
937 /* Return the diagnostic message string if TYPE is not valid as a
938 function return type, NULL otherwise. */
939 const char *(*invalid_return_type) (const_tree type);
941 /* If values of TYPE are promoted to some other type when used in
942 expressions (analogous to the integer promotions), return that type,
943 or NULL_TREE otherwise. */
944 tree (*promoted_type) (const_tree type);
946 /* Convert EXPR to TYPE, if target-specific types with special conversion
947 rules are involved. Return the converted expression, or NULL to apply
948 the standard conversion rules. */
949 tree (*convert_to_type) (tree type, tree expr);
951 /* Return the array of IRA cover classes for the current target. */
952 const enum reg_class *(*ira_cover_classes) (void);
954 /* Return the class for a secondary reload, and fill in extra information. */
955 enum reg_class (*secondary_reload) (bool, rtx, enum reg_class,
957 struct secondary_reload_info *);
959 /* This target hook allows the backend to perform additional
960 processing while initializing for variable expansion. */
961 void (* expand_to_rtl_hook) (void);
963 /* This target hook allows the backend to perform additional
964 instantiations on rtx that are not actually in insns yet,
965 but will be later. */
966 void (* instantiate_decls) (void);
968 /* Return true if is OK to use a hard register REGNO as scratch register
970 bool (* hard_regno_scratch_ok) (unsigned int regno);
972 /* Return the smallest number of different values for which it is best to
973 use a jump-table instead of a tree of conditional branches. */
974 unsigned int (* case_values_threshold) (void);
976 /* Retutn true if a function must have and use a frame pointer. */
977 bool (* frame_pointer_required) (void);
979 /* Returns true if the compiler is allowed to try to replace register number
980 from-reg with register number to-reg. */
981 bool (* can_eliminate) (const int, const int);
983 /* Functions specific to the C family of frontends. */
985 /* Return machine mode for non-standard suffix
986 or VOIDmode if non-standard suffixes are unsupported. */
987 enum machine_mode (*mode_for_suffix) (char);
990 /* Functions specific to the C++ frontend. */
992 /* Return the integer type used for guard variables. */
993 tree (*guard_type) (void);
994 /* Return true if only the low bit of the guard should be tested. */
995 bool (*guard_mask_bit) (void);
996 /* Returns the size of the array cookie for an array of type. */
997 tree (*get_cookie_size) (tree);
998 /* Returns true if the element size should be stored in the
1000 bool (*cookie_has_size) (void);
1001 /* Allows backends to perform additional processing when
1002 deciding if a class should be exported or imported. */
1003 int (*import_export_class) (tree, int);
1004 /* Returns true if constructors and destructors return "this". */
1005 bool (*cdtor_returns_this) (void);
1006 /* Returns true if the key method for a class can be an inline
1007 function, so long as it is not declared inline in the class
1008 itself. Returning true is the behavior required by the Itanium
1010 bool (*key_method_may_be_inline) (void);
1011 /* DECL is a virtual table, virtual table table, typeinfo object,
1012 or other similar implicit class data object that will be
1013 emitted with external linkage in this translation unit. No ELF
1014 visibility has been explicitly specified. If the target needs
1015 to specify a visibility other than that of the containing class,
1016 use this hook to set DECL_VISIBILITY and
1017 DECL_VISIBILITY_SPECIFIED. */
1018 void (*determine_class_data_visibility) (tree decl);
1019 /* Returns true (the default) if virtual tables and other
1020 similar implicit class data objects are always COMDAT if they
1021 have external linkage. If this hook returns false, then
1022 class data for classes whose virtual table will be emitted in
1023 only one translation unit will not be COMDAT. */
1024 bool (*class_data_always_comdat) (void);
1025 /* Returns true (the default) if the RTTI for the basic types,
1026 which is always defined in the C++ runtime, should be COMDAT;
1027 false if it should not be COMDAT. */
1028 bool (*library_rtti_comdat) (void);
1029 /* Returns true if __aeabi_atexit should be used to register static
1031 bool (*use_aeabi_atexit) (void);
1032 /* Returns true if target may use atexit in the same manner as
1033 __cxa_atexit to register static destructors. */
1034 bool (*use_atexit_for_cxa_atexit) (void);
1035 /* TYPE is a C++ class (i.e., RECORD_TYPE or UNION_TYPE) that
1036 has just been defined. Use this hook to make adjustments to the
1037 class (eg, tweak visibility or perform any other required
1038 target modifications). */
1039 void (*adjust_class_at_definition) (tree type);
1042 /* Functions and data for emulated TLS support. */
1044 /* Name of the address and common functions. */
1045 const char *get_address;
1046 const char *register_common;
1048 /* Prefixes for proxy variable and template. */
1049 const char *var_section;
1050 const char *tmpl_section;
1052 /* Prefixes for proxy variable and template. */
1053 const char *var_prefix;
1054 const char *tmpl_prefix;
1056 /* Function to generate field definitions of the proxy variable. */
1057 tree (*var_fields) (tree, tree *);
1059 /* Function to initialize a proxy variable. */
1060 tree (*var_init) (tree, tree, tree);
1062 /* Whether we are allowed to alter the usual alignment of the
1064 bool var_align_fixed;
1066 /* Whether we can emit debug information for TLS vars. */
1067 bool debug_form_tls_address;
1070 struct target_option_hooks {
1071 /* Function to validate the attribute((option(...))) strings or NULL. If
1072 the option is validated, it is assumed that DECL_FUNCTION_SPECIFIC will
1073 be filled in in the function decl node. */
1074 bool (*valid_attribute_p) (tree, tree, tree, int);
1076 /* Function to save any extra target state in the target options
1078 void (*save) (struct cl_target_option *);
1080 /* Function to restore any extra target state from the target options
1082 void (*restore) (struct cl_target_option *);
1084 /* Function to print any extra target state from the target options
1086 void (*print) (FILE *, int, struct cl_target_option *);
1088 /* Function to parse arguments to be validated for #pragma option, and to
1089 change the state if the options are valid. If the first argument is
1090 NULL, the second argument specifies the default options to use. Return
1091 true if the options are valid, and set the current state. */
1092 bool (*pragma_parse) (tree, tree);
1094 /* Function to determine if one function can inline another function. */
1095 bool (*can_inline_p) (tree, tree);
1098 /* For targets that need to mark extra registers as live on entry to
1099 the function, they should define this target hook and set their
1100 bits in the bitmap passed in. */
1101 void (*live_on_entry) (bitmap);
1103 /* True if unwinding tables should be generated by default. */
1104 bool unwind_tables_default;
1106 /* Leave the boolean fields at the end. */
1108 /* True if arbitrary sections are supported. */
1109 bool have_named_sections;
1111 /* True if we can create zeroed data by switching to a BSS section
1112 and then using ASM_OUTPUT_SKIP to allocate the space. */
1113 bool have_switchable_bss_sections;
1115 /* True if "native" constructors and destructors are supported,
1116 false if we're using collect2 for the job. */
1117 bool have_ctors_dtors;
1119 /* True if thread-local storage is supported. */
1122 /* True if a small readonly data section is supported. */
1123 bool have_srodata_section;
1125 /* True if EH frame info sections should be zero-terminated. */
1126 bool terminate_dw2_eh_frame_info;
1128 /* True if #NO_APP should be emitted at the beginning of
1130 bool file_start_app_off;
1132 /* True if output_file_directive should be called for main_input_filename
1133 at the beginning of assembly output. */
1134 bool file_start_file_directive;
1136 /* True if #pragma extern_prefix is to be supported. */
1137 bool handle_pragma_extern_prefix;
1139 /* True if the target is allowed to reorder memory accesses unless
1140 synchronization is explicitly requested. */
1141 bool relaxed_ordering;
1143 /* Returns true if we should generate exception tables for use with the
1144 ARM EABI. The effects the encoding of function exception specifications.
1146 bool arm_eabi_unwinder;
1148 /* Leave the boolean fields at the end. */
1151 extern struct gcc_target targetm;
1153 struct gcc_targetcm {
1154 /* Handle target switch CODE (an OPT_* value). ARG is the argument
1155 passed to the switch; it is NULL if no argument was. VALUE is the
1156 value of ARG if CODE specifies a UInteger option, otherwise it is
1157 1 if the positive form of the switch was used and 0 if the negative
1158 form was. Return true if the switch was valid. */
1159 bool (*handle_c_option) (size_t code, const char *arg, int value);
1162 /* Each target can provide their own. */
1163 extern struct gcc_targetcm targetcm;
1165 #endif /* GCC_TARGET_H */