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);
257 /* Emit the trampoline template. This hook may be NULL. */
258 void (*trampoline_template) (FILE *);
261 /* Functions relating to instruction scheduling. */
264 /* Given the current cost, COST, of an insn, INSN, calculate and
265 return a new cost based on its relationship to DEP_INSN through
266 the dependence LINK. The default is to make no adjustment. */
267 int (* adjust_cost) (rtx insn, rtx link, rtx dep_insn, int cost);
269 /* Adjust the priority of an insn as you see fit. Returns the new
271 int (* adjust_priority) (rtx, int);
273 /* Function which returns the maximum number of insns that can be
274 scheduled in the same machine cycle. This must be constant
275 over an entire compilation. The default is 1. */
276 int (* issue_rate) (void);
278 /* Calculate how much this insn affects how many more insns we
279 can emit this cycle. Default is they all cost the same. */
280 int (* variable_issue) (FILE *, int, rtx, int);
282 /* Initialize machine-dependent scheduling code. */
283 void (* md_init) (FILE *, int, int);
285 /* Finalize machine-dependent scheduling code. */
286 void (* md_finish) (FILE *, int);
288 /* Initialize machine-dependent function wide scheduling code. */
289 void (* md_init_global) (FILE *, int, int);
291 /* Finalize machine-dependent function wide scheduling code. */
292 void (* md_finish_global) (FILE *, int);
294 /* Reorder insns in a machine-dependent fashion, in two different
295 places. Default does nothing. */
296 int (* reorder) (FILE *, int, rtx *, int *, int);
297 int (* reorder2) (FILE *, int, rtx *, int *, int);
299 /* The following member value is a pointer to a function called
300 after evaluation forward dependencies of insns in chain given
301 by two parameter values (head and tail correspondingly). */
302 void (* dependencies_evaluation_hook) (rtx, rtx);
304 /* The values of the following four members are pointers to
305 functions used to simplify the automaton descriptions.
306 dfa_pre_cycle_insn and dfa_post_cycle_insn give functions
307 returning insns which are used to change the pipeline hazard
308 recognizer state when the new simulated processor cycle
309 correspondingly starts and finishes. The function defined by
310 init_dfa_pre_cycle_insn and init_dfa_post_cycle_insn are used
311 to initialize the corresponding insns. The default values of
312 the members result in not changing the automaton state when
313 the new simulated processor cycle correspondingly starts and
315 void (* init_dfa_pre_cycle_insn) (void);
316 rtx (* dfa_pre_cycle_insn) (void);
317 void (* init_dfa_post_cycle_insn) (void);
318 rtx (* dfa_post_cycle_insn) (void);
320 /* The values of the following two members are pointers to
321 functions used to simplify the automaton descriptions.
322 dfa_pre_advance_cycle and dfa_post_advance_cycle are getting called
323 immediately before and after cycle is advanced. */
324 void (* dfa_pre_advance_cycle) (void);
325 void (* dfa_post_advance_cycle) (void);
327 /* The following member value is a pointer to a function returning value
328 which defines how many insns in queue `ready' will we try for
329 multi-pass scheduling. If the member value is nonzero and the
330 function returns positive value, the DFA based scheduler will make
331 multi-pass scheduling for the first cycle. In other words, we will
332 try to choose ready insn which permits to start maximum number of
333 insns on the same cycle. */
334 int (* first_cycle_multipass_dfa_lookahead) (void);
336 /* The following member value is pointer to a function controlling
337 what insns from the ready insn queue will be considered for the
338 multipass insn scheduling. If the hook returns zero for insn
339 passed as the parameter, the insn will be not chosen to be
341 int (* first_cycle_multipass_dfa_lookahead_guard) (rtx);
343 /* The following member value is pointer to a function called by
344 the insn scheduler before issuing insn passed as the third
345 parameter on given cycle. If the hook returns nonzero, the
346 insn is not issued on given processors cycle. Instead of that,
347 the processor cycle is advanced. If the value passed through
348 the last parameter is zero, the insn ready queue is not sorted
349 on the new cycle start as usually. The first parameter passes
350 file for debugging output. The second one passes the scheduler
351 verbose level of the debugging output. The forth and the fifth
352 parameter values are correspondingly processor cycle on which
353 the previous insn has been issued and the current processor
355 int (* dfa_new_cycle) (FILE *, int, rtx, int, int, int *);
357 /* The following member value is a pointer to a function called by the
358 insn scheduler. It should return true if there exists a dependence
359 which is considered costly by the target, between the insn
360 DEP_PRO (&_DEP), and the insn DEP_CON (&_DEP). The first parameter is
361 the dep that represents the dependence between the two insns. The
362 second argument is the cost of the dependence as estimated by
363 the scheduler. The last argument is the distance in cycles
364 between the already scheduled insn (first parameter) and the
365 second insn (second parameter). */
366 bool (* is_costly_dependence) (struct _dep *_dep, int, int);
368 /* Given the current cost, COST, of an insn, INSN, calculate and
369 return a new cost based on its relationship to DEP_INSN through the
370 dependence of type DEP_TYPE. The default is to make no adjustment. */
371 int (* adjust_cost_2) (rtx insn, int, rtx dep_insn, int cost, int dw);
373 /* The following member value is a pointer to a function called
374 by the insn scheduler. This hook is called to notify the backend
375 that new instructions were emitted. */
376 void (* h_i_d_extended) (void);
378 /* Next 5 functions are for multi-point scheduling. */
380 /* Allocate memory for scheduler context. */
381 void *(* alloc_sched_context) (void);
383 /* Fills the context from the local machine scheduler context. */
384 void (* init_sched_context) (void *, bool);
386 /* Sets local machine scheduler context to a saved value. */
387 void (* set_sched_context) (void *);
389 /* Clears a scheduler context so it becomes like after init. */
390 void (* clear_sched_context) (void *);
392 /* Frees the scheduler context. */
393 void (* free_sched_context) (void *);
395 /* The following member value is a pointer to a function called
396 by the insn scheduler.
397 The first parameter is an instruction, the second parameter is the type
398 of the requested speculation, and the third parameter is a pointer to the
399 speculative pattern of the corresponding type (set if return value == 1).
401 -1, if there is no pattern, that will satisfy the requested speculation
403 0, if current pattern satisfies the requested speculation type,
404 1, if pattern of the instruction should be changed to the newly
406 int (* speculate_insn) (rtx, int, rtx *);
408 /* The following member value is a pointer to a function called
409 by the insn scheduler. It should return true if the check instruction
410 passed as the parameter needs a recovery block. */
411 bool (* needs_block_p) (int);
413 /* The following member value is a pointer to a function called
414 by the insn scheduler. It should return a pattern for the check
416 The first parameter is a speculative instruction, the second parameter
417 is the label of the corresponding recovery block (or null, if it is a
418 simple check). If the mutation of the check is requested (e.g. from
419 ld.c to chk.a), the third parameter is true - in this case the first
420 parameter is the previous check. */
421 rtx (* gen_spec_check) (rtx, rtx, int);
423 /* The following member value is a pointer to a function controlling
424 what insns from the ready insn queue will be considered for the
425 multipass insn scheduling. If the hook returns zero for the insn
426 passed as the parameter, the insn will not be chosen to be
427 issued. This hook is used to discard speculative instructions,
428 that stand at the first position of the ready list. */
429 bool (* first_cycle_multipass_dfa_lookahead_guard_spec) (const_rtx);
431 /* The following member value is a pointer to a function that provides
432 information about the speculation capabilities of the target.
433 The parameter is a pointer to spec_info variable. */
434 void (* set_sched_flags) (struct spec_info_def *);
436 /* Return speculation types of the instruction passed as the parameter. */
437 int (* get_insn_spec_ds) (rtx);
439 /* Return speculation types that are checked for the instruction passed as
441 int (* get_insn_checked_ds) (rtx);
443 /* Return bool if rtx scanning should just skip current layer and
444 advance to the inner rtxes. */
445 bool (* skip_rtx_p) (const_rtx);
447 /* The following member value is a pointer to a function that provides
448 information about the target resource-based lower bound which is
449 used by the swing modulo scheduler. The parameter is a pointer
451 int (* sms_res_mii) (struct ddg *);
454 /* Functions relating to vectorization. */
457 /* The following member value is a pointer to a function called
458 by the vectorizer, and return the decl of the target builtin
460 tree (* builtin_mask_for_load) (void);
462 /* Returns a code for builtin that realizes vectorized version of
463 function, or NULL_TREE if not available. */
464 tree (* builtin_vectorized_function) (unsigned, tree, tree);
466 /* Returns a code for builtin that realizes vectorized version of
467 conversion, or NULL_TREE if not available. */
468 tree (* builtin_conversion) (unsigned, tree);
470 /* Target builtin that implements vector widening multiplication.
471 builtin_mul_widen_eve computes the element-by-element products
472 for the even elements, and builtin_mul_widen_odd computes the
473 element-by-element products for the odd elements. */
474 tree (* builtin_mul_widen_even) (tree);
475 tree (* builtin_mul_widen_odd) (tree);
477 /* Returns the cost to be added to the overheads involved with
478 executing the vectorized version of a loop. */
479 int (*builtin_vectorization_cost) (bool);
481 /* Return true if vector alignment is reachable (by peeling N
482 iterations) for the given type. */
483 bool (* vector_alignment_reachable) (const_tree, bool);
485 /* Target builtin that implements vector permute. */
486 tree (* builtin_vec_perm) (tree, tree*);
487 /* Return true if the target supports misaligned store/load of a
488 specific factor denoted in the third parameter. The last parameter
489 is true if the access is defined in a packed struct. */
490 bool (* builtin_support_vector_misalignment) (enum machine_mode,
491 const_tree, int, bool);
494 /* The initial value of target_flags. */
495 int default_target_flags;
497 /* Handle target switch CODE (an OPT_* value). ARG is the argument
498 passed to the switch; it is NULL if no argument was. VALUE is the
499 value of ARG if CODE specifies a UInteger option, otherwise it is
500 1 if the positive form of the switch was used and 0 if the negative
501 form was. Return true if the switch was valid. */
502 bool (* handle_option) (size_t code, const char *arg, int value);
504 /* Display extra, target specific information in response to a
505 --target-help switch. */
506 void (* target_help) (void);
508 /* Return machine mode for filter value. */
509 enum machine_mode (* eh_return_filter_mode) (void);
511 /* Return machine mode for libgcc expanded cmp instructions. */
512 enum machine_mode (* libgcc_cmp_return_mode) (void);
514 /* Return machine mode for libgcc expanded shift instructions. */
515 enum machine_mode (* libgcc_shift_count_mode) (void);
517 /* Return machine mode to be used for _Unwind_Word type. */
518 enum machine_mode (* unwind_word_mode) (void);
520 /* Given two decls, merge their attributes and return the result. */
521 tree (* merge_decl_attributes) (tree, tree);
523 /* Given two types, merge their attributes and return the result. */
524 tree (* merge_type_attributes) (tree, tree);
526 /* Table of machine attributes and functions to handle them.
528 const struct attribute_spec *attribute_table;
530 /* Return zero if the attributes on TYPE1 and TYPE2 are incompatible,
531 one if they are compatible and two if they are nearly compatible
532 (which causes a warning to be generated). */
533 int (* comp_type_attributes) (const_tree type1, const_tree type2);
535 /* Assign default attributes to the newly defined TYPE. */
536 void (* set_default_type_attributes) (tree type);
538 /* Insert attributes on the newly created DECL. */
539 void (* insert_attributes) (tree decl, tree *attributes);
541 /* Return true if FNDECL (which has at least one machine attribute)
542 can be inlined despite its machine attributes, false otherwise. */
543 bool (* function_attribute_inlinable_p) (const_tree fndecl);
545 /* Return true if bitfields in RECORD_TYPE should follow the
546 Microsoft Visual C++ bitfield layout rules. */
547 bool (* ms_bitfield_layout_p) (const_tree record_type);
549 /* True if the target supports decimal floating point. */
550 bool (* decimal_float_supported_p) (void);
552 /* True if the target supports fixed-point. */
553 bool (* fixed_point_supported_p) (void);
555 /* Return true if anonymous bitfields affect structure alignment. */
556 bool (* align_anon_bitfield) (void);
558 /* Return true if volatile bitfields should use the narrowest type possible.
559 Return false if they should use the container type. */
560 bool (* narrow_volatile_bitfield) (void);
562 /* Set up target-specific built-in functions. */
563 void (* init_builtins) (void);
565 /* Initialize (if INITIALIZE_P is true) and return the target-specific
566 built-in function decl for CODE.
567 Return NULL if that is not possible. Return error_mark_node if CODE
568 is outside of the range of valid target builtin function codes. */
569 tree (* builtin_decl) (unsigned code, bool initialize_p);
571 /* Expand a target-specific builtin. */
572 rtx (* expand_builtin) (tree exp, rtx target, rtx subtarget,
573 enum machine_mode mode, int ignore);
575 /* Select a replacement for a target-specific builtin. This is done
576 *before* regular type checking, and so allows the target to
577 implement a crude form of function overloading. The result is a
578 complete expression that implements the operation. PARAMS really
579 has type VEC(tree,gc)*, but we don't want to include tree.h
581 tree (*resolve_overloaded_builtin) (unsigned int /*location_t*/,
582 tree decl, void *params);
584 /* Fold a target-specific builtin. */
585 tree (* fold_builtin) (tree fndecl, tree arglist, bool ignore);
587 /* Returns a code for a target-specific builtin that implements
588 reciprocal of the function, or NULL_TREE if not available. */
589 tree (* builtin_reciprocal) (unsigned, bool, bool);
591 /* For a vendor-specific TYPE, return a pointer to a statically-allocated
592 string containing the C++ mangling for TYPE. In all other cases, return
594 const char * (* mangle_type) (const_tree type);
596 /* Make any adjustments to libfunc names needed for this target. */
597 void (* init_libfuncs) (void);
599 /* Given a decl, a section name, and whether the decl initializer
600 has relocs, choose attributes for the section. */
601 /* ??? Should be merged with SELECT_SECTION and UNIQUE_SECTION. */
602 unsigned int (* section_type_flags) (tree, const char *, int);
604 /* True if new jumps cannot be created, to replace existing ones or
605 not, at the current point in the compilation. */
606 bool (* cannot_modify_jumps_p) (void);
608 /* Return a register class for which branch target register
609 optimizations should be applied. */
610 enum reg_class (* branch_target_register_class) (void);
612 /* Return true if branch target register optimizations should include
613 callee-saved registers that are not already live during the current
614 function. AFTER_PE_GEN is true if prologues and epilogues have
615 already been generated. */
616 bool (* branch_target_register_callee_saved) (bool after_pe_gen);
618 /* True if the constant X cannot be placed in the constant pool. */
619 bool (* cannot_force_const_mem) (rtx);
621 /* True if the insn X cannot be duplicated. */
622 bool (* cannot_copy_insn_p) (rtx);
624 /* True if X is considered to be commutative. */
625 bool (* commutative_p) (const_rtx, int);
627 /* Given an invalid address X for a given machine mode, try machine-specific
628 ways to make it legitimate. Return X or an invalid address on failure. */
629 rtx (* legitimize_address) (rtx, rtx, enum machine_mode);
631 /* Given an address RTX, undo the effects of LEGITIMIZE_ADDRESS. */
632 rtx (* delegitimize_address) (rtx);
634 /* Given an address RTX, say whether it is valid. */
635 bool (* legitimate_address_p) (enum machine_mode, rtx, bool);
637 /* True if the given constant can be put into an object_block. */
638 bool (* use_blocks_for_constant_p) (enum machine_mode, const_rtx);
640 /* The minimum and maximum byte offsets for anchored addresses. */
641 HOST_WIDE_INT min_anchor_offset;
642 HOST_WIDE_INT max_anchor_offset;
644 /* True if section anchors can be used to access the given symbol. */
645 bool (* use_anchors_for_symbol_p) (const_rtx);
647 /* True if it is OK to do sibling call optimization for the specified
648 call expression EXP. DECL will be the called function, or NULL if
649 this is an indirect call. */
650 bool (*function_ok_for_sibcall) (tree decl, tree exp);
652 /* Establish appropriate back-end context for processing the function
653 FNDECL. The argument might be NULL to indicate processing at top
654 level, outside of any function scope. */
655 void (*set_current_function) (tree fndecl);
657 /* True if EXP should be placed in a "small data" section. */
658 bool (* in_small_data_p) (const_tree);
660 /* True if EXP names an object for which name resolution must resolve
661 to the current executable or shared library. */
662 bool (* binds_local_p) (const_tree);
664 /* Modify and return the identifier of a DECL's external name,
665 originally identified by ID, as required by the target,
666 (eg, append @nn to windows32 stdcall function names).
667 The default is to return ID without modification. */
668 tree (* mangle_decl_assembler_name) (tree decl, tree id);
670 /* Do something target-specific to record properties of the DECL into
671 the associated SYMBOL_REF. */
672 void (* encode_section_info) (tree, rtx, int);
674 /* Undo the effects of encode_section_info on the symbol string. */
675 const char * (* strip_name_encoding) (const char *);
677 /* If shift optabs for MODE are known to always truncate the shift count,
678 return the mask that they apply. Return 0 otherwise. */
679 unsigned HOST_WIDE_INT (* shift_truncation_mask) (enum machine_mode mode);
681 /* Return the number of divisions in the given MODE that should be present,
682 so that it is profitable to turn the division into a multiplication by
684 unsigned int (* min_divisions_for_recip_mul) (enum machine_mode mode);
686 /* If the representation of integral MODE is such that values are
687 always sign-extended to a wider mode MODE_REP then return
688 SIGN_EXTEND. Return UNKNOWN otherwise. */
689 /* Note that the return type ought to be RTX_CODE, but that's not
690 necessarily defined at this point. */
691 int (* mode_rep_extended) (enum machine_mode mode,
692 enum machine_mode mode_rep);
694 /* True if MODE is valid for a pointer in __attribute__((mode("MODE"))). */
695 bool (* valid_pointer_mode) (enum machine_mode mode);
697 /* True if MODE is valid for the target. By "valid", we mean able to
698 be manipulated in non-trivial ways. In particular, this means all
699 the arithmetic is supported. */
700 bool (* scalar_mode_supported_p) (enum machine_mode mode);
702 /* Similarly for vector modes. "Supported" here is less strict. At
703 least some operations are supported; need to check optabs or builtins
704 for further details. */
705 bool (* vector_mode_supported_p) (enum machine_mode mode);
707 /* Compute a (partial) cost for rtx X. Return true if the complete
708 cost has been computed, and false if subexpressions should be
709 scanned. In either case, *TOTAL contains the cost result. */
710 /* Note that CODE and OUTER_CODE ought to be RTX_CODE, but that's
711 not necessarily defined at this point. */
712 bool (* rtx_costs) (rtx x, int code, int outer_code, int *total, bool speed);
714 /* Compute the cost of X, used as an address. Never called with
715 invalid addresses. */
716 int (* address_cost) (rtx x, bool speed);
718 /* Return where to allocate pseudo for a given hard register initial
720 rtx (* allocate_initial_value) (rtx x);
722 /* Return nonzero if evaluating UNSPEC[_VOLATILE] X might cause a trap.
723 FLAGS has the same meaning as in rtlanal.c: may_trap_p_1. */
724 int (* unspec_may_trap_p) (const_rtx x, unsigned flags);
726 /* Given a register, this hook should return a parallel of registers
727 to represent where to find the register pieces. Define this hook
728 if the register and its mode are represented in Dwarf in
729 non-contiguous locations, or if the register should be
730 represented in more than one register in Dwarf. Otherwise, this
731 hook should return NULL_RTX. */
732 rtx (* dwarf_register_span) (rtx);
734 /* If expand_builtin_init_dwarf_reg_sizes needs to fill in table
735 entries not corresponding directly to registers below
736 FIRST_PSEUDO_REGISTER, this hook should generate the necessary
737 code, given the address of the table. */
738 void (* init_dwarf_reg_sizes_extra) (tree);
740 /* Fetch the fixed register(s) which hold condition codes, for
741 targets where it makes sense to look for duplicate assignments to
742 the condition codes. This should return true if there is such a
743 register, false otherwise. The arguments should be set to the
744 fixed register numbers. Up to two condition code registers are
745 supported. If there is only one for this target, the int pointed
746 at by the second argument should be set to -1. */
747 bool (* fixed_condition_code_regs) (unsigned int *, unsigned int *);
749 /* If two condition code modes are compatible, return a condition
750 code mode which is compatible with both, such that a comparison
751 done in the returned mode will work for both of the original
752 modes. If the condition code modes are not compatible, return
754 enum machine_mode (* cc_modes_compatible) (enum machine_mode,
757 /* Do machine-dependent code transformations. Called just before
758 delayed-branch scheduling. */
759 void (* machine_dependent_reorg) (void);
761 /* Create the __builtin_va_list type. */
762 tree (* build_builtin_va_list) (void);
764 /* Get the cfun/fndecl calling abi __builtin_va_list type. */
765 tree (* fn_abi_va_list) (tree);
767 /* Get the __builtin_va_list type dependent on input type. */
768 tree (* canonical_va_list_type) (tree);
770 /* Expand the __builtin_va_start builtin. */
771 void (* expand_builtin_va_start) (tree valist, rtx nextarg);
773 /* Gimplifies a VA_ARG_EXPR. */
774 tree (* gimplify_va_arg_expr) (tree valist, tree type, gimple_seq *pre_p,
777 /* Validity-checking routines for PCH files, target-specific.
778 get_pch_validity returns a pointer to the data to be stored,
779 and stores the size in its argument. pch_valid_p gets the same
780 information back and returns NULL if the PCH is valid,
781 or an error message if not.
783 void * (* get_pch_validity) (size_t *);
784 const char * (* pch_valid_p) (const void *, size_t);
786 /* If nonnull, this function checks whether a PCH file with the
787 given set of target flags can be used. It returns NULL if so,
788 otherwise it returns an error message. */
789 const char *(*check_pch_target_flags) (int);
791 /* True if the compiler should give an enum type only as many
792 bytes as it takes to represent the range of possible values of
794 bool (* default_short_enums) (void);
796 /* This target hook returns an rtx that is used to store the address
797 of the current frame into the built-in setjmp buffer. */
798 rtx (* builtin_setjmp_frame_value) (void);
800 /* This target hook should add STRING_CST trees for any hard regs
801 the port wishes to automatically clobber for an asm. */
802 tree (* md_asm_clobbers) (tree, tree, tree);
804 /* This target hook allows the backend to specify a calling convention
805 in the debug information. This function actually returns an
806 enum dwarf_calling_convention, but because of forward declarations
807 and not wanting to include dwarf2.h everywhere target.h is included
808 the function is being declared as an int. */
809 int (* dwarf_calling_convention) (const_tree);
811 /* This target hook allows the backend to emit frame-related insns that
812 contain UNSPECs or UNSPEC_VOLATILEs. The call frame debugging info
813 engine will invoke it on insns of the form
814 (set (reg) (unspec [...] UNSPEC_INDEX))
816 (set (reg) (unspec_volatile [...] UNSPECV_INDEX))
817 to let the backend emit the call frame instructions. */
818 void (* dwarf_handle_frame_unspec) (const char *, rtx, int);
820 /* Perform architecture specific checking of statements gimplified
821 from VA_ARG_EXPR. STMT is the statement. Returns true if the statement
822 doesn't need to be checked for va_list references. */
823 bool (* stdarg_optimize_hook) (struct stdarg_info *ai, const_gimple stmt);
825 /* This target hook allows the operating system to override the DECL
826 that represents the external variable that contains the stack
827 protection guard variable. The type of this DECL is ptr_type_node. */
828 tree (* stack_protect_guard) (void);
830 /* This target hook allows the operating system to override the CALL_EXPR
831 that is invoked when a check vs the guard variable fails. */
832 tree (* stack_protect_fail) (void);
834 /* Returns NULL if target supports the insn within a doloop block,
835 otherwise it returns an error message. */
836 const char * (*invalid_within_doloop) (const_rtx);
838 /* DECL is a variable or function with __attribute__((dllimport))
839 specified. Use this hook if the target needs to add extra validation
840 checks to handle_dll_attribute (). */
841 bool (* valid_dllimport_attribute_p) (const_tree decl);
843 /* If non-zero, align constant anchors in CSE to a multiple of this
845 unsigned HOST_WIDE_INT const_anchor;
847 /* Functions relating to calls - argument passing, returns, etc. */
849 enum machine_mode (*promote_function_mode) (const_tree type,
850 enum machine_mode mode,
854 bool (*promote_prototypes) (const_tree fntype);
855 rtx (*struct_value_rtx) (tree fndecl, int incoming);
856 bool (*return_in_memory) (const_tree type, const_tree fndecl);
857 bool (*return_in_msb) (const_tree type);
859 /* Return true if a parameter must be passed by reference. TYPE may
860 be null if this is a libcall. CA may be null if this query is
861 from __builtin_va_arg. */
862 bool (*pass_by_reference) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
863 const_tree type, bool named_arg);
865 rtx (*expand_builtin_saveregs) (void);
866 /* Returns pretend_argument_size. */
867 void (*setup_incoming_varargs) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
868 tree type, int *pretend_arg_size,
870 bool (*strict_argument_naming) (CUMULATIVE_ARGS *ca);
871 /* Returns true if we should use
872 targetm.calls.setup_incoming_varargs() and/or
873 targetm.calls.strict_argument_naming(). */
874 bool (*pretend_outgoing_varargs_named) (CUMULATIVE_ARGS *ca);
876 /* Given a complex type T, return true if a parameter of type T
877 should be passed as two scalars. */
878 bool (* split_complex_arg) (const_tree type);
880 /* Return true if type T, mode MODE, may not be passed in registers,
881 but must be passed on the stack. */
882 /* ??? This predicate should be applied strictly after pass-by-reference.
883 Need audit to verify that this is the case. */
884 bool (* must_pass_in_stack) (enum machine_mode mode, const_tree t);
886 /* Return true if type TYPE, mode MODE, which is passed by reference,
887 should have the object copy generated by the callee rather than
888 the caller. It is never called for TYPE requiring constructors. */
889 bool (* callee_copies) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
890 const_tree type, bool named);
892 /* Return zero for arguments passed entirely on the stack or entirely
893 in registers. If passed in both, return the number of bytes passed
894 in registers; the balance is therefore passed on the stack. */
895 int (* arg_partial_bytes) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
896 tree type, bool named);
898 /* Return the diagnostic message string if function without a prototype
899 is not allowed for this 'val' argument; NULL otherwise. */
900 const char *(*invalid_arg_for_unprototyped_fn) (const_tree typelist,
904 /* Return an rtx for the return value location of the function
905 specified by FN_DECL_OR_TYPE with a return type of RET_TYPE. */
906 rtx (*function_value) (const_tree ret_type, const_tree fn_decl_or_type,
909 /* Return the rtx for the result of a libcall of mode MODE,
910 calling the function FN_NAME. */
911 rtx (*libcall_value) (enum machine_mode, const_rtx);
913 /* Return an rtx for the argument pointer incoming to the
915 rtx (*internal_arg_pointer) (void);
917 /* Update the current function stack boundary if needed. */
918 void (*update_stack_boundary) (void);
920 /* Handle stack alignment and return an rtx for Dynamic Realign
921 Argument Pointer if necessary. */
922 rtx (*get_drap_rtx) (void);
924 /* Return true if all function parameters should be spilled to the
926 bool (*allocate_stack_slots_for_args) (void);
928 /* Return an rtx for the static chain for FNDECL. If INCOMING_P is true,
929 then it should be for the callee; otherwise for the caller. */
930 rtx (*static_chain) (const_tree fndecl, bool incoming_p);
932 /* Fill in the trampoline at MEM with a call to FNDECL and a
933 static chain value of CHAIN. */
934 void (*trampoline_init) (rtx mem, tree fndecl, rtx chain);
936 /* Adjust the address of the trampoline in a target-specific way. */
937 rtx (*trampoline_adjust_address) (rtx addr);
940 /* Return the diagnostic message string if conversion from FROMTYPE
941 to TOTYPE is not allowed, NULL otherwise. */
942 const char *(*invalid_conversion) (const_tree fromtype, const_tree totype);
944 /* Return the diagnostic message string if the unary operation OP is
945 not permitted on TYPE, NULL otherwise. */
946 const char *(*invalid_unary_op) (int op, const_tree type);
948 /* Return the diagnostic message string if the binary operation OP
949 is not permitted on TYPE1 and TYPE2, NULL otherwise. */
950 const char *(*invalid_binary_op) (int op, const_tree type1, const_tree type2);
952 /* Return the diagnostic message string if TYPE is not valid as a
953 function parameter type, NULL otherwise. */
954 const char *(*invalid_parameter_type) (const_tree type);
956 /* Return the diagnostic message string if TYPE is not valid as a
957 function return type, NULL otherwise. */
958 const char *(*invalid_return_type) (const_tree type);
960 /* If values of TYPE are promoted to some other type when used in
961 expressions (analogous to the integer promotions), return that type,
962 or NULL_TREE otherwise. */
963 tree (*promoted_type) (const_tree type);
965 /* Convert EXPR to TYPE, if target-specific types with special conversion
966 rules are involved. Return the converted expression, or NULL to apply
967 the standard conversion rules. */
968 tree (*convert_to_type) (tree type, tree expr);
970 /* Return the array of IRA cover classes for the current target. */
971 const enum reg_class *(*ira_cover_classes) (void);
973 /* Return the class for a secondary reload, and fill in extra information. */
974 enum reg_class (*secondary_reload) (bool, rtx, enum reg_class,
976 struct secondary_reload_info *);
978 /* This target hook allows the backend to perform additional
979 processing while initializing for variable expansion. */
980 void (* expand_to_rtl_hook) (void);
982 /* This target hook allows the backend to perform additional
983 instantiations on rtx that are not actually in insns yet,
984 but will be later. */
985 void (* instantiate_decls) (void);
987 /* Return true if is OK to use a hard register REGNO as scratch register
989 bool (* hard_regno_scratch_ok) (unsigned int regno);
991 /* Return the smallest number of different values for which it is best to
992 use a jump-table instead of a tree of conditional branches. */
993 unsigned int (* case_values_threshold) (void);
995 /* Retutn true if a function must have and use a frame pointer. */
996 bool (* frame_pointer_required) (void);
998 /* Returns true if the compiler is allowed to try to replace register number
999 from-reg with register number to-reg. */
1000 bool (* can_eliminate) (const int, const int);
1002 /* Functions specific to the C family of frontends. */
1004 /* Return machine mode for non-standard suffix
1005 or VOIDmode if non-standard suffixes are unsupported. */
1006 enum machine_mode (*mode_for_suffix) (char);
1009 /* Functions specific to the C++ frontend. */
1011 /* Return the integer type used for guard variables. */
1012 tree (*guard_type) (void);
1013 /* Return true if only the low bit of the guard should be tested. */
1014 bool (*guard_mask_bit) (void);
1015 /* Returns the size of the array cookie for an array of type. */
1016 tree (*get_cookie_size) (tree);
1017 /* Returns true if the element size should be stored in the
1019 bool (*cookie_has_size) (void);
1020 /* Allows backends to perform additional processing when
1021 deciding if a class should be exported or imported. */
1022 int (*import_export_class) (tree, int);
1023 /* Returns true if constructors and destructors return "this". */
1024 bool (*cdtor_returns_this) (void);
1025 /* Returns true if the key method for a class can be an inline
1026 function, so long as it is not declared inline in the class
1027 itself. Returning true is the behavior required by the Itanium
1029 bool (*key_method_may_be_inline) (void);
1030 /* DECL is a virtual table, virtual table table, typeinfo object,
1031 or other similar implicit class data object that will be
1032 emitted with external linkage in this translation unit. No ELF
1033 visibility has been explicitly specified. If the target needs
1034 to specify a visibility other than that of the containing class,
1035 use this hook to set DECL_VISIBILITY and
1036 DECL_VISIBILITY_SPECIFIED. */
1037 void (*determine_class_data_visibility) (tree decl);
1038 /* Returns true (the default) if virtual tables and other
1039 similar implicit class data objects are always COMDAT if they
1040 have external linkage. If this hook returns false, then
1041 class data for classes whose virtual table will be emitted in
1042 only one translation unit will not be COMDAT. */
1043 bool (*class_data_always_comdat) (void);
1044 /* Returns true (the default) if the RTTI for the basic types,
1045 which is always defined in the C++ runtime, should be COMDAT;
1046 false if it should not be COMDAT. */
1047 bool (*library_rtti_comdat) (void);
1048 /* Returns true if __aeabi_atexit should be used to register static
1050 bool (*use_aeabi_atexit) (void);
1051 /* Returns true if target may use atexit in the same manner as
1052 __cxa_atexit to register static destructors. */
1053 bool (*use_atexit_for_cxa_atexit) (void);
1054 /* TYPE is a C++ class (i.e., RECORD_TYPE or UNION_TYPE) that
1055 has just been defined. Use this hook to make adjustments to the
1056 class (eg, tweak visibility or perform any other required
1057 target modifications). */
1058 void (*adjust_class_at_definition) (tree type);
1061 /* Functions and data for emulated TLS support. */
1063 /* Name of the address and common functions. */
1064 const char *get_address;
1065 const char *register_common;
1067 /* Prefixes for proxy variable and template. */
1068 const char *var_section;
1069 const char *tmpl_section;
1071 /* Prefixes for proxy variable and template. */
1072 const char *var_prefix;
1073 const char *tmpl_prefix;
1075 /* Function to generate field definitions of the proxy variable. */
1076 tree (*var_fields) (tree, tree *);
1078 /* Function to initialize a proxy variable. */
1079 tree (*var_init) (tree, tree, tree);
1081 /* Whether we are allowed to alter the usual alignment of the
1083 bool var_align_fixed;
1085 /* Whether we can emit debug information for TLS vars. */
1086 bool debug_form_tls_address;
1089 struct target_option_hooks {
1090 /* Function to validate the attribute((option(...))) strings or NULL. If
1091 the option is validated, it is assumed that DECL_FUNCTION_SPECIFIC will
1092 be filled in in the function decl node. */
1093 bool (*valid_attribute_p) (tree, tree, tree, int);
1095 /* Function to save any extra target state in the target options
1097 void (*save) (struct cl_target_option *);
1099 /* Function to restore any extra target state from the target options
1101 void (*restore) (struct cl_target_option *);
1103 /* Function to print any extra target state from the target options
1105 void (*print) (FILE *, int, struct cl_target_option *);
1107 /* Function to parse arguments to be validated for #pragma option, and to
1108 change the state if the options are valid. If the first argument is
1109 NULL, the second argument specifies the default options to use. Return
1110 true if the options are valid, and set the current state. */
1111 bool (*pragma_parse) (tree, tree);
1113 /* Function to determine if one function can inline another function. */
1114 bool (*can_inline_p) (tree, tree);
1117 /* For targets that need to mark extra registers as live on entry to
1118 the function, they should define this target hook and set their
1119 bits in the bitmap passed in. */
1120 void (*live_on_entry) (bitmap);
1122 /* True if unwinding tables should be generated by default. */
1123 bool unwind_tables_default;
1125 /* Leave the boolean fields at the end. */
1127 /* True if arbitrary sections are supported. */
1128 bool have_named_sections;
1130 /* True if we can create zeroed data by switching to a BSS section
1131 and then using ASM_OUTPUT_SKIP to allocate the space. */
1132 bool have_switchable_bss_sections;
1134 /* True if "native" constructors and destructors are supported,
1135 false if we're using collect2 for the job. */
1136 bool have_ctors_dtors;
1138 /* True if thread-local storage is supported. */
1141 /* True if a small readonly data section is supported. */
1142 bool have_srodata_section;
1144 /* True if EH frame info sections should be zero-terminated. */
1145 bool terminate_dw2_eh_frame_info;
1147 /* True if #NO_APP should be emitted at the beginning of
1149 bool file_start_app_off;
1151 /* True if output_file_directive should be called for main_input_filename
1152 at the beginning of assembly output. */
1153 bool file_start_file_directive;
1155 /* True if #pragma extern_prefix is to be supported. */
1156 bool handle_pragma_extern_prefix;
1158 /* True if the target is allowed to reorder memory accesses unless
1159 synchronization is explicitly requested. */
1160 bool relaxed_ordering;
1162 /* Returns true if we should generate exception tables for use with the
1163 ARM EABI. The effects the encoding of function exception specifications.
1165 bool arm_eabi_unwinder;
1167 /* Leave the boolean fields at the end. */
1170 extern struct gcc_target targetm;
1172 struct gcc_targetcm {
1173 /* Handle target switch CODE (an OPT_* value). ARG is the argument
1174 passed to the switch; it is NULL if no argument was. VALUE is the
1175 value of ARG if CODE specifies a UInteger option, otherwise it is
1176 1 if the positive form of the switch was used and 0 if the negative
1177 form was. Return true if the switch was valid. */
1178 bool (*handle_c_option) (size_t code, const char *arg, int value);
1181 /* Each target can provide their own. */
1182 extern struct gcc_targetcm targetcm;
1184 #endif /* GCC_TARGET_H */
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