1 /* Data structure definitions for a generic GCC target.
2 Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007
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 2, 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; if not, write to the Free Software
17 Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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! */
23 /* This file contains a data structure that describes a GCC target.
24 At present it is incomplete, but in future it should grow to
25 contain most or all target machine and target O/S specific
28 This structure has its initializer declared in target-def.h in the
29 form of large macro TARGET_INITIALIZER that expands to many smaller
32 The smaller macros each initialize one component of the structure,
33 and each has a default. Each target should have a file that
34 includes target.h and target-def.h, and overrides any inappropriate
35 defaults by undefining the relevant macro and defining a suitable
36 replacement. That file should then contain the definition of
39 struct gcc_target targetm = TARGET_INITIALIZER;
41 Doing things this way allows us to bring together everything that
42 defines a GCC target. By supplying a default that is appropriate
43 to most targets, we can easily add new items without needing to
44 edit dozens of target configuration files. It should also allow us
45 to gradually reduce the amount of conditional compilation that is
46 scattered throughout GCC. */
52 #include "insn-modes.h"
57 /* The struct used by the secondary_reload target hook. */
58 typedef struct secondary_reload_info
60 /* icode is actually an enum insn_code, but we don't want to force every
61 file that includes target.h to include optabs.h . */
63 int extra_cost; /* Cost for using (a) scratch register(s) to be taken
64 into account by copy_cost. */
65 /* The next two members are for the use of the backward
66 compatibility hook. */
67 struct secondary_reload_info *prev_sri;
68 int t_icode; /* Actually an enum insn_code - see above. */
69 } secondary_reload_info;
74 /* Functions that output assembler for the target. */
77 /* Opening and closing parentheses for asm expression grouping. */
78 const char *open_paren, *close_paren;
80 /* Assembler instructions for creating various kinds of integer object. */
88 } aligned_op, unaligned_op;
90 /* Try to output the assembler code for an integer object whose
91 value is given by X. SIZE is the size of the object in bytes and
92 ALIGNED_P indicates whether it is aligned. Return true if
93 successful. Only handles cases for which BYTE_OP, ALIGNED_OP
94 and UNALIGNED_OP are NULL. */
95 bool (* integer) (rtx x, unsigned int size, int aligned_p);
97 /* Output code that will globalize a label. */
98 void (* globalize_label) (FILE *, const char *);
100 /* Output code that will emit a label for unwind info, if this
101 target requires such labels. Second argument is the decl the
102 unwind info is associated with, third is a boolean: true if
103 this is for exception handling, fourth is a boolean: true if
104 this is only a placeholder for an omitted FDE. */
105 void (* unwind_label) (FILE *, tree, int, int);
107 /* Output code that will emit a label to divide up the exception
109 void (* except_table_label) (FILE *);
111 /* Emit any directives required to unwind this instruction. */
112 void (* unwind_emit) (FILE *, rtx);
114 /* Output an internal label. */
115 void (* internal_label) (FILE *, const char *, unsigned long);
117 /* Emit a ttype table reference to a typeinfo object. */
118 bool (* ttype) (rtx);
120 /* Emit an assembler directive to set visibility for the symbol
121 associated with the tree decl. */
122 void (* visibility) (tree, int);
124 /* Output the assembler code for entry to a function. */
125 void (* function_prologue) (FILE *, HOST_WIDE_INT);
127 /* Output the assembler code for end of prologue. */
128 void (* function_end_prologue) (FILE *);
130 /* Output the assembler code for start of epilogue. */
131 void (* function_begin_epilogue) (FILE *);
133 /* Output the assembler code for function exit. */
134 void (* function_epilogue) (FILE *, HOST_WIDE_INT);
136 /* Initialize target-specific sections. */
137 void (* init_sections) (void);
139 /* Tell assembler to change to section NAME with attributes FLAGS.
140 If DECL is non-NULL, it is the VAR_DECL or FUNCTION_DECL with
141 which this section is associated. */
142 void (* named_section) (const char *name, unsigned int flags, tree decl);
144 /* Return a mask describing how relocations should be treated when
145 selecting sections. Bit 1 should be set if global relocations
146 should be placed in a read-write section; bit 0 should be set if
147 local relocations should be placed in a read-write section. */
148 int (*reloc_rw_mask) (void);
150 /* Return a section for EXP. It may be a DECL or a constant. RELOC
151 is nonzero if runtime relocations must be applied; bit 1 will be
152 set if the runtime relocations require non-local name resolution.
153 ALIGN is the required alignment of the data. */
154 section *(* select_section) (tree, int, unsigned HOST_WIDE_INT);
156 /* Return a section for X. MODE is X's mode and ALIGN is its
157 alignment in bits. */
158 section *(* select_rtx_section) (enum machine_mode, rtx,
159 unsigned HOST_WIDE_INT);
161 /* Select a unique section name for DECL. RELOC is the same as
162 for SELECT_SECTION. */
163 void (* unique_section) (tree, int);
165 /* Return the readonly data section associated with function DECL. */
166 section *(* function_rodata_section) (tree);
168 /* Output a constructor for a symbol with a given priority. */
169 void (* constructor) (rtx, int);
171 /* Output a destructor for a symbol with a given priority. */
172 void (* destructor) (rtx, int);
174 /* Output the assembler code for a thunk function. THUNK_DECL is the
175 declaration for the thunk function itself, FUNCTION is the decl for
176 the target function. DELTA is an immediate constant offset to be
177 added to THIS. If VCALL_OFFSET is nonzero, the word at
178 *(*this + vcall_offset) should be added to THIS. */
179 void (* output_mi_thunk) (FILE *file, tree thunk_decl,
180 HOST_WIDE_INT delta, HOST_WIDE_INT vcall_offset,
183 /* Determine whether output_mi_thunk would succeed. */
184 /* ??? Ideally, this hook would not exist, and success or failure
185 would be returned from output_mi_thunk directly. But there's
186 too much undo-able setup involved in invoking output_mi_thunk.
187 Could be fixed by making output_mi_thunk emit rtl instead of
188 text to the output file. */
189 bool (* can_output_mi_thunk) (tree thunk_decl, HOST_WIDE_INT delta,
190 HOST_WIDE_INT vcall_offset,
193 /* Output any boilerplate text needed at the beginning of a
195 void (*file_start) (void);
197 /* Output any boilerplate text needed at the end of a
199 void (*file_end) (void);
201 /* Output an assembler pseudo-op to declare a library function name
203 void (*external_libcall) (rtx);
205 /* Output an assembler directive to mark decl live. This instructs
206 linker to not dead code strip this symbol. */
207 void (*mark_decl_preserved) (const char *);
209 /* Output the definition of a section anchor. */
210 void (*output_anchor) (rtx);
212 /* Output a DTP-relative reference to a TLS symbol. */
213 void (*output_dwarf_dtprel) (FILE *file, int size, rtx x);
217 /* Functions relating to instruction scheduling. */
220 /* Given the current cost, COST, of an insn, INSN, calculate and
221 return a new cost based on its relationship to DEP_INSN through
222 the dependence LINK. The default is to make no adjustment. */
223 int (* adjust_cost) (rtx insn, rtx link, rtx def_insn, int cost);
225 /* Adjust the priority of an insn as you see fit. Returns the new
227 int (* adjust_priority) (rtx, int);
229 /* Function which returns the maximum number of insns that can be
230 scheduled in the same machine cycle. This must be constant
231 over an entire compilation. The default is 1. */
232 int (* issue_rate) (void);
234 /* Calculate how much this insn affects how many more insns we
235 can emit this cycle. Default is they all cost the same. */
236 int (* variable_issue) (FILE *, int, rtx, int);
238 /* Initialize machine-dependent scheduling code. */
239 void (* md_init) (FILE *, int, int);
241 /* Finalize machine-dependent scheduling code. */
242 void (* md_finish) (FILE *, int);
244 /* Initialize machine-dependent function while scheduling code. */
245 void (* md_init_global) (FILE *, int, int);
247 /* Finalize machine-dependent function wide scheduling code. */
248 void (* md_finish_global) (FILE *, int);
250 /* Reorder insns in a machine-dependent fashion, in two different
251 places. Default does nothing. */
252 int (* reorder) (FILE *, int, rtx *, int *, int);
253 int (* reorder2) (FILE *, int, rtx *, int *, int);
255 /* The following member value is a pointer to a function called
256 after evaluation forward dependencies of insns in chain given
257 by two parameter values (head and tail correspondingly). */
258 void (* dependencies_evaluation_hook) (rtx, rtx);
260 /* The values of the following four members are pointers to
261 functions used to simplify the automaton descriptions.
262 dfa_pre_cycle_insn and dfa_post_cycle_insn give functions
263 returning insns which are used to change the pipeline hazard
264 recognizer state when the new simulated processor cycle
265 correspondingly starts and finishes. The function defined by
266 init_dfa_pre_cycle_insn and init_dfa_post_cycle_insn are used
267 to initialize the corresponding insns. The default values of
268 the members result in not changing the automaton state when
269 the new simulated processor cycle correspondingly starts and
271 void (* init_dfa_pre_cycle_insn) (void);
272 rtx (* dfa_pre_cycle_insn) (void);
273 void (* init_dfa_post_cycle_insn) (void);
274 rtx (* dfa_post_cycle_insn) (void);
276 /* The following member value is a pointer to a function returning value
277 which defines how many insns in queue `ready' will we try for
278 multi-pass scheduling. If the member value is nonzero and the
279 function returns positive value, the DFA based scheduler will make
280 multi-pass scheduling for the first cycle. In other words, we will
281 try to choose ready insn which permits to start maximum number of
282 insns on the same cycle. */
283 int (* first_cycle_multipass_dfa_lookahead) (void);
285 /* The following member value is pointer to a function controlling
286 what insns from the ready insn queue will be considered for the
287 multipass insn scheduling. If the hook returns zero for insn
288 passed as the parameter, the insn will be not chosen to be
290 int (* first_cycle_multipass_dfa_lookahead_guard) (rtx);
292 /* The following member value is pointer to a function called by
293 the insn scheduler before issuing insn passed as the third
294 parameter on given cycle. If the hook returns nonzero, the
295 insn is not issued on given processors cycle. Instead of that,
296 the processor cycle is advanced. If the value passed through
297 the last parameter is zero, the insn ready queue is not sorted
298 on the new cycle start as usually. The first parameter passes
299 file for debugging output. The second one passes the scheduler
300 verbose level of the debugging output. The forth and the fifth
301 parameter values are correspondingly processor cycle on which
302 the previous insn has been issued and the current processor
304 int (* dfa_new_cycle) (FILE *, int, rtx, int, int, int *);
306 /* The following member value is a pointer to a function called
307 by the insn scheduler. It should return true if there exists a
308 dependence which is considered costly by the target, between
309 the insn passed as the first parameter, and the insn passed as
310 the second parameter. The third parameter is the INSN_DEPEND
311 link that represents the dependence between the two insns. The
312 fourth argument is the cost of the dependence as estimated by
313 the scheduler. The last argument is the distance in cycles
314 between the already scheduled insn (first parameter) and the
315 the second insn (second parameter). */
316 bool (* is_costly_dependence) (rtx, rtx, rtx, int, int);
318 /* Given the current cost, COST, of an insn, INSN, calculate and
319 return a new cost based on its relationship to DEP_INSN through the
320 dependence of type DEP_TYPE. The default is to make no adjustment. */
321 int (* adjust_cost_2) (rtx insn, int, rtx def_insn, int cost);
323 /* The following member value is a pointer to a function called
324 by the insn scheduler. This hook is called to notify the backend
325 that new instructions were emitted. */
326 void (* h_i_d_extended) (void);
328 /* The following member value is a pointer to a function called
329 by the insn scheduler.
330 The first parameter is an instruction, the second parameter is the type
331 of the requested speculation, and the third parameter is a pointer to the
332 speculative pattern of the corresponding type (set if return value == 1).
334 -1, if there is no pattern, that will satisfy the requested speculation
336 0, if current pattern satisfies the requested speculation type,
337 1, if pattern of the instruction should be changed to the newly
339 int (* speculate_insn) (rtx, int, rtx *);
341 /* The following member value is a pointer to a function called
342 by the insn scheduler. It should return true if the check instruction
343 corresponding to the instruction passed as the parameter needs a
345 bool (* needs_block_p) (rtx);
347 /* The following member value is a pointer to a function called
348 by the insn scheduler. It should return a pattern for the check
350 The first parameter is a speculative instruction, the second parameter
351 is the label of the corresponding recovery block (or null, if it is a
352 simple check). If the mutation of the check is requested (e.g. from
353 ld.c to chk.a), the third parameter is true - in this case the first
354 parameter is the previous check. */
355 rtx (* gen_check) (rtx, rtx, bool);
357 /* The following member value is a pointer to a function controlling
358 what insns from the ready insn queue will be considered for the
359 multipass insn scheduling. If the hook returns zero for the insn
360 passed as the parameter, the insn will not be chosen to be
361 issued. This hook is used to discard speculative instructions,
362 that stand at the first position of the ready list. */
363 bool (* first_cycle_multipass_dfa_lookahead_guard_spec) (rtx);
365 /* The following member value is a pointer to a function that provides
366 information about the speculation capabilities of the target.
367 The parameter is a pointer to spec_info variable. */
368 void (* set_sched_flags) (struct spec_info_def *);
371 /* Functions relating to vectorization. */
374 /* The following member value is a pointer to a function called
375 by the vectorizer, and return the decl of the target builtin
377 tree (* builtin_mask_for_load) (void);
379 /* Return true if vector alignment is reachable (by peeling N
380 interations) for the given type. */
381 bool (* vector_alignment_reachable) (tree, bool);
384 /* The initial value of target_flags. */
385 int default_target_flags;
387 /* Handle target switch CODE (an OPT_* value). ARG is the argument
388 passed to the switch; it is NULL if no argument was. VALUE is the
389 value of ARG if CODE specifies a UInteger option, otherwise it is
390 1 if the positive form of the switch was used and 0 if the negative
391 form was. Return true if the switch was valid. */
392 bool (* handle_option) (size_t code, const char *arg, int value);
394 /* Return machine mode for filter value. */
395 enum machine_mode (* eh_return_filter_mode) (void);
397 /* Given two decls, merge their attributes and return the result. */
398 tree (* merge_decl_attributes) (tree, tree);
400 /* Given two types, merge their attributes and return the result. */
401 tree (* merge_type_attributes) (tree, tree);
403 /* Table of machine attributes and functions to handle them.
405 const struct attribute_spec *attribute_table;
407 /* Return zero if the attributes on TYPE1 and TYPE2 are incompatible,
408 one if they are compatible and two if they are nearly compatible
409 (which causes a warning to be generated). */
410 int (* comp_type_attributes) (tree type1, tree type2);
412 /* Assign default attributes to the newly defined TYPE. */
413 void (* set_default_type_attributes) (tree type);
415 /* Insert attributes on the newly created DECL. */
416 void (* insert_attributes) (tree decl, tree *attributes);
418 /* Return true if FNDECL (which has at least one machine attribute)
419 can be inlined despite its machine attributes, false otherwise. */
420 bool (* function_attribute_inlinable_p) (tree fndecl);
422 /* Return true if bitfields in RECORD_TYPE should follow the
423 Microsoft Visual C++ bitfield layout rules. */
424 bool (* ms_bitfield_layout_p) (tree record_type);
426 /* True if the target supports decimal floating point. */
427 bool (* decimal_float_supported_p) (void);
429 /* Return true if anonymous bitfields affect structure alignment. */
430 bool (* align_anon_bitfield) (void);
432 /* Return true if volatile bitfields should use the narrowest type possible.
433 Return false if they should use the container type. */
434 bool (* narrow_volatile_bitfield) (void);
436 /* Set up target-specific built-in functions. */
437 void (* init_builtins) (void);
439 /* Expand a target-specific builtin. */
440 rtx (* expand_builtin) (tree exp, rtx target, rtx subtarget,
441 enum machine_mode mode, int ignore);
443 /* Select a replacement for a target-specific builtin. This is done
444 *before* regular type checking, and so allows the target to implement
445 a crude form of function overloading. The result is a complete
446 expression that implements the operation. */
447 tree (*resolve_overloaded_builtin) (tree decl, tree params);
449 /* Fold a target-specific builtin. */
450 tree (* fold_builtin) (tree fndecl, tree arglist, bool ignore);
452 /* For a vendor-specific fundamental TYPE, return a pointer to
453 a statically-allocated string containing the C++ mangling for
454 TYPE. In all other cases, return NULL. */
455 const char * (* mangle_fundamental_type) (tree type);
457 /* Make any adjustments to libfunc names needed for this target. */
458 void (* init_libfuncs) (void);
460 /* Given a decl, a section name, and whether the decl initializer
461 has relocs, choose attributes for the section. */
462 /* ??? Should be merged with SELECT_SECTION and UNIQUE_SECTION. */
463 unsigned int (* section_type_flags) (tree, const char *, int);
465 /* True if new jumps cannot be created, to replace existing ones or
466 not, at the current point in the compilation. */
467 bool (* cannot_modify_jumps_p) (void);
469 /* Return a register class for which branch target register
470 optimizations should be applied. */
471 int (* branch_target_register_class) (void);
473 /* Return true if branch target register optimizations should include
474 callee-saved registers that are not already live during the current
475 function. AFTER_PE_GEN is true if prologues and epilogues have
476 already been generated. */
477 bool (* branch_target_register_callee_saved) (bool after_pe_gen);
479 /* True if the constant X cannot be placed in the constant pool. */
480 bool (* cannot_force_const_mem) (rtx);
482 /* True if the insn X cannot be duplicated. */
483 bool (* cannot_copy_insn_p) (rtx);
485 /* True if X is considered to be commutative. */
486 bool (* commutative_p) (rtx, int);
488 /* Given an address RTX, undo the effects of LEGITIMIZE_ADDRESS. */
489 rtx (* delegitimize_address) (rtx);
491 /* True if the given constant can be put into an object_block. */
492 bool (* use_blocks_for_constant_p) (enum machine_mode, rtx);
494 /* The minimum and maximum byte offsets for anchored addresses. */
495 HOST_WIDE_INT min_anchor_offset;
496 HOST_WIDE_INT max_anchor_offset;
498 /* True if section anchors can be used to access the given symbol. */
499 bool (* use_anchors_for_symbol_p) (rtx);
501 /* True if it is OK to do sibling call optimization for the specified
502 call expression EXP. DECL will be the called function, or NULL if
503 this is an indirect call. */
504 bool (*function_ok_for_sibcall) (tree decl, tree exp);
506 /* True if EXP should be placed in a "small data" section. */
507 bool (* in_small_data_p) (tree);
509 /* True if EXP names an object for which name resolution must resolve
510 to the current module. */
511 bool (* binds_local_p) (tree);
513 /* Do something target-specific to record properties of the DECL into
514 the associated SYMBOL_REF. */
515 void (* encode_section_info) (tree, rtx, int);
517 /* Undo the effects of encode_section_info on the symbol string. */
518 const char * (* strip_name_encoding) (const char *);
520 /* If shift optabs for MODE are known to always truncate the shift count,
521 return the mask that they apply. Return 0 otherwise. */
522 unsigned HOST_WIDE_INT (* shift_truncation_mask) (enum machine_mode mode);
524 /* Return the number of divisions in the given MODE that should be present,
525 so that it is profitable to turn the division into a multiplication by
527 unsigned int (* min_divisions_for_recip_mul) (enum machine_mode mode);
529 /* If the representation of integral MODE is such that values are
530 always sign-extended to a wider mode MODE_REP then return
531 SIGN_EXTEND. Return UNKNOWN otherwise. */
532 /* Note that the return type ought to be RTX_CODE, but that's not
533 necessarily defined at this point. */
534 int (* mode_rep_extended) (enum machine_mode mode,
535 enum machine_mode mode_rep);
537 /* True if MODE is valid for a pointer in __attribute__((mode("MODE"))). */
538 bool (* valid_pointer_mode) (enum machine_mode mode);
540 /* True if MODE is valid for the target. By "valid", we mean able to
541 be manipulated in non-trivial ways. In particular, this means all
542 the arithmetic is supported. */
543 bool (* scalar_mode_supported_p) (enum machine_mode mode);
545 /* Similarly for vector modes. "Supported" here is less strict. At
546 least some operations are supported; need to check optabs or builtins
547 for further details. */
548 bool (* vector_mode_supported_p) (enum machine_mode mode);
550 /* True if a vector is opaque. */
551 bool (* vector_opaque_p) (tree);
553 /* Compute a (partial) cost for rtx X. Return true if the complete
554 cost has been computed, and false if subexpressions should be
555 scanned. In either case, *TOTAL contains the cost result. */
556 /* Note that CODE and OUTER_CODE ought to be RTX_CODE, but that's
557 not necessarily defined at this point. */
558 bool (* rtx_costs) (rtx x, int code, int outer_code, int *total);
560 /* Compute the cost of X, used as an address. Never called with
561 invalid addresses. */
562 int (* address_cost) (rtx x);
564 /* Return where to allocate pseudo for a given hard register initial
566 rtx (* allocate_initial_value) (rtx x);
568 /* Given a register, this hook should return a parallel of registers
569 to represent where to find the register pieces. Define this hook
570 if the register and its mode are represented in Dwarf in
571 non-contiguous locations, or if the register should be
572 represented in more than one register in Dwarf. Otherwise, this
573 hook should return NULL_RTX. */
574 rtx (* dwarf_register_span) (rtx);
576 /* Fetch the fixed register(s) which hold condition codes, for
577 targets where it makes sense to look for duplicate assignments to
578 the condition codes. This should return true if there is such a
579 register, false otherwise. The arguments should be set to the
580 fixed register numbers. Up to two condition code registers are
581 supported. If there is only one for this target, the int pointed
582 at by the second argument should be set to -1. */
583 bool (* fixed_condition_code_regs) (unsigned int *, unsigned int *);
585 /* If two condition code modes are compatible, return a condition
586 code mode which is compatible with both, such that a comparison
587 done in the returned mode will work for both of the original
588 modes. If the condition code modes are not compatible, return
590 enum machine_mode (* cc_modes_compatible) (enum machine_mode,
593 /* Do machine-dependent code transformations. Called just before
594 delayed-branch scheduling. */
595 void (* machine_dependent_reorg) (void);
597 /* Create the __builtin_va_list type. */
598 tree (* build_builtin_va_list) (void);
600 /* Gimplifies a VA_ARG_EXPR. */
601 tree (* gimplify_va_arg_expr) (tree valist, tree type, tree *pre_p,
604 /* Validity-checking routines for PCH files, target-specific.
605 get_pch_validity returns a pointer to the data to be stored,
606 and stores the size in its argument. pch_valid_p gets the same
607 information back and returns NULL if the PCH is valid,
608 or an error message if not.
610 void * (* get_pch_validity) (size_t *);
611 const char * (* pch_valid_p) (const void *, size_t);
613 /* If nonnull, this function checks whether a PCH file with the
614 given set of target flags can be used. It returns NULL if so,
615 otherwise it returns an error message. */
616 const char *(*check_pch_target_flags) (int);
618 /* True if the compiler should give an enum type only as many
619 bytes as it takes to represent the range of possible values of
621 bool (* default_short_enums) (void);
623 /* This target hook returns an rtx that is used to store the address
624 of the current frame into the built-in setjmp buffer. */
625 rtx (* builtin_setjmp_frame_value) (void);
627 /* This target hook should add STRING_CST trees for any hard regs
628 the port wishes to automatically clobber for an asm. */
629 tree (* md_asm_clobbers) (tree, tree, tree);
631 /* This target hook allows the backend to specify a calling convention
632 in the debug information. This function actually returns an
633 enum dwarf_calling_convention, but because of forward declarations
634 and not wanting to include dwarf2.h everywhere target.h is included
635 the function is being declared as an int. */
636 int (* dwarf_calling_convention) (tree);
638 /* This target hook allows the backend to emit frame-related insns that
639 contain UNSPECs or UNSPEC_VOLATILEs. The call frame debugging info
640 engine will invoke it on insns of the form
641 (set (reg) (unspec [...] UNSPEC_INDEX))
643 (set (reg) (unspec_volatile [...] UNSPECV_INDEX))
644 to let the backend emit the call frame instructions. */
645 void (* dwarf_handle_frame_unspec) (const char *, rtx, int);
647 /* Perform architecture specific checking of statements gimplified
648 from VA_ARG_EXPR. LHS is left hand side of MODIFY_EXPR, RHS
649 is right hand side. Returns true if the statements doesn't need
650 to be checked for va_list references. */
651 bool (* stdarg_optimize_hook) (struct stdarg_info *ai, tree lhs, tree rhs);
653 /* This target hook allows the operating system to override the DECL
654 that represents the external variable that contains the stack
655 protection guard variable. The type of this DECL is ptr_type_node. */
656 tree (* stack_protect_guard) (void);
658 /* This target hook allows the operating system to override the CALL_EXPR
659 that is invoked when a check vs the guard variable fails. */
660 tree (* stack_protect_fail) (void);
662 /* Returns NULL if target supports the insn within a doloop block,
663 otherwise it returns an error message. */
664 const char * (*invalid_within_doloop) (rtx);
666 /* DECL is a variable or function with __attribute__((dllimport))
667 specified. Use this hook if the target needs to add extra validation
668 checks to handle_dll_attribute (). */
669 bool (* valid_dllimport_attribute_p) (tree decl);
671 /* Functions relating to calls - argument passing, returns, etc. */
673 bool (*promote_function_args) (tree fntype);
674 bool (*promote_function_return) (tree fntype);
675 bool (*promote_prototypes) (tree fntype);
676 rtx (*struct_value_rtx) (tree fndecl, int incoming);
677 bool (*return_in_memory) (tree type, tree fndecl);
678 bool (*return_in_msb) (tree type);
680 /* Return true if a parameter must be passed by reference. TYPE may
681 be null if this is a libcall. CA may be null if this query is
682 from __builtin_va_arg. */
683 bool (*pass_by_reference) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
684 tree type, bool named_arg);
686 rtx (*expand_builtin_saveregs) (void);
687 /* Returns pretend_argument_size. */
688 void (*setup_incoming_varargs) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
689 tree type, int *pretend_arg_size,
691 bool (*strict_argument_naming) (CUMULATIVE_ARGS *ca);
692 /* Returns true if we should use
693 targetm.calls.setup_incoming_varargs() and/or
694 targetm.calls.strict_argument_naming(). */
695 bool (*pretend_outgoing_varargs_named) (CUMULATIVE_ARGS *ca);
697 /* Given a complex type T, return true if a parameter of type T
698 should be passed as two scalars. */
699 bool (* split_complex_arg) (tree type);
701 /* Return true if type T, mode MODE, may not be passed in registers,
702 but must be passed on the stack. */
703 /* ??? This predicate should be applied strictly after pass-by-reference.
704 Need audit to verify that this is the case. */
705 bool (* must_pass_in_stack) (enum machine_mode mode, tree t);
707 /* Return true if type TYPE, mode MODE, which is passed by reference,
708 should have the object copy generated by the callee rather than
709 the caller. It is never called for TYPE requiring constructors. */
710 bool (* callee_copies) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
711 tree type, bool named);
713 /* Return zero for arguments passed entirely on the stack or entirely
714 in registers. If passed in both, return the number of bytes passed
715 in registers; the balance is therefore passed on the stack. */
716 int (* arg_partial_bytes) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
717 tree type, bool named);
719 /* Return the diagnostic message string if function without a prototype
720 is not allowed for this 'val' argument; NULL otherwise. */
721 const char *(*invalid_arg_for_unprototyped_fn) (tree typelist,
722 tree funcdecl, tree val);
724 /* Return an rtx for the return value location of the function
725 specified by FN_DECL_OR_TYPE with a return type of RET_TYPE. */
726 rtx (*function_value) (tree ret_type, tree fn_decl_or_type,
729 /* Return an rtx for the argument pointer incoming to the
731 rtx (*internal_arg_pointer) (void);
734 /* Return the diagnostic message string if conversion from FROMTYPE
735 to TOTYPE is not allowed, NULL otherwise. */
736 const char *(*invalid_conversion) (tree fromtype, tree totype);
738 /* Return the diagnostic message string if the unary operation OP is
739 not permitted on TYPE, NULL otherwise. */
740 const char *(*invalid_unary_op) (int op, tree type);
742 /* Return the diagnostic message string if the binary operation OP
743 is not permitted on TYPE1 and TYPE2, NULL otherwise. */
744 const char *(*invalid_binary_op) (int op, tree type1, tree type2);
746 /* Return the class for a secondary reload, and fill in extra information. */
747 enum reg_class (*secondary_reload) (bool, rtx, enum reg_class,
749 struct secondary_reload_info *);
751 /* Functions specific to the C++ frontend. */
753 /* Return the integer type used for guard variables. */
754 tree (*guard_type) (void);
755 /* Return true if only the low bit of the guard should be tested. */
756 bool (*guard_mask_bit) (void);
757 /* Returns the size of the array cookie for an array of type. */
758 tree (*get_cookie_size) (tree);
759 /* Returns true if the element size should be stored in the
761 bool (*cookie_has_size) (void);
762 /* Allows backends to perform additional processing when
763 deciding if a class should be exported or imported. */
764 int (*import_export_class) (tree, int);
765 /* Returns true if constructors and destructors return "this". */
766 bool (*cdtor_returns_this) (void);
767 /* Returns true if the key method for a class can be an inline
768 function, so long as it is not declared inline in the class
769 itself. Returning true is the behavior required by the Itanium
771 bool (*key_method_may_be_inline) (void);
772 /* DECL is a virtual table, virtual table table, typeinfo object,
773 or other similar implicit class data object that will be
774 emitted with external linkage in this translation unit. No ELF
775 visibility has been explicitly specified. If the target needs
776 to specify a visibility other than that of the containing class,
777 use this hook to set DECL_VISIBILITY and
778 DECL_VISIBILITY_SPECIFIED. */
779 void (*determine_class_data_visibility) (tree decl);
780 /* Returns true (the default) if virtual tables and other
781 similar implicit class data objects are always COMDAT if they
782 have external linkage. If this hook returns false, then
783 class data for classes whose virtual table will be emitted in
784 only one translation unit will not be COMDAT. */
785 bool (*class_data_always_comdat) (void);
786 /* Returns true (the default) if the RTTI for the basic types,
787 which is always defined in the C++ runtime, should be COMDAT;
788 false if it should not be COMDAT. */
789 bool (*library_rtti_comdat) (void);
790 /* Returns true if __aeabi_atexit should be used to register static
792 bool (*use_aeabi_atexit) (void);
793 /* TYPE is a C++ class (i.e., RECORD_TYPE or UNION_TYPE) that
794 has just been defined. Use this hook to make adjustments to the
795 class (eg, tweak visibility or perform any other required
796 target modifications). */
797 void (*adjust_class_at_definition) (tree type);
800 /* For targets that need to mark extra registers as live on entry to
801 the function, they should define this target hook and set their
802 bits in the bitmap passed in. */
803 void (*live_on_entry) (bitmap);
805 /* True if unwinding tables should be generated by default. */
806 bool unwind_tables_default;
808 /* Leave the boolean fields at the end. */
810 /* True if arbitrary sections are supported. */
811 bool have_named_sections;
813 /* True if we can create zeroed data by switching to a BSS section
814 and then using ASM_OUTPUT_SKIP to allocate the space. */
815 bool have_switchable_bss_sections;
817 /* True if "native" constructors and destructors are supported,
818 false if we're using collect2 for the job. */
819 bool have_ctors_dtors;
821 /* True if thread-local storage is supported. */
824 /* True if a small readonly data section is supported. */
825 bool have_srodata_section;
827 /* True if EH frame info sections should be zero-terminated. */
828 bool terminate_dw2_eh_frame_info;
830 /* True if #NO_APP should be emitted at the beginning of
832 bool file_start_app_off;
834 /* True if output_file_directive should be called for main_input_filename
835 at the beginning of assembly output. */
836 bool file_start_file_directive;
838 /* True if #pragma redefine_extname is to be supported. */
839 bool handle_pragma_redefine_extname;
841 /* True if #pragma extern_prefix is to be supported. */
842 bool handle_pragma_extern_prefix;
844 /* True if the target is allowed to reorder memory accesses unless
845 synchronization is explicitly requested. */
846 bool relaxed_ordering;
848 /* Returns true if we should generate exception tables for use with the
849 ARM EABI. The effects the encoding of function exception specifications.
851 bool arm_eabi_unwinder;
853 /* Leave the boolean fields at the end. */
856 extern struct gcc_target targetm;
858 #endif /* GCC_TARGET_H */